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Chideme C, Chikobvu D, Makoni T. Blood donation projections using hierarchical time series forecasting: the case of Zimbabwe's national blood bank. BMC Public Health 2024; 24:928. [PMID: 38556866 PMCID: PMC10983681 DOI: 10.1186/s12889-024-18185-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 02/22/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND The discrepancy between blood supply and demand requires accurate forecasts of the blood supply at any blood bank. Accurate blood donation forecasting gives blood managers empirical evidence in blood inventory management. The study aims to model and predict blood donations in Zimbabwe using hierarchical time series. The modelling technique allows one to identify, say, a declining donor category, and in that way, the method offers feasible and targeted solutions for blood managers to work on. METHODS The monthly blood donation data covering the period 2007 to 2018, collected from the National Blood Service Zimbabwe (NBSZ) was used. The data was disaggregated by gender and blood groups types within each gender category. The model validation involved utilising actual blood donation data from 2019 and 2020. The model's performance was evaluated through the Mean Absolute Percentage Error (MAPE), uncovering expected and notable discrepancies during the Covid-19 pandemic period only. RESULTS Blood group O had the highest monthly yield mean of 1507.85 and 1230.03 blood units for male and female donors, respectively. The top-down forecasting proportions (TDFP) under ARIMA, with a MAPE value of 11.30, was selected as the best approach and the model was then used to forecast future blood donations. The blood donation predictions for 2019 had a MAPE value of 14.80, suggesting alignment with previous years' donations. However, starting in April 2020, the Covid-19 pandemic disrupted blood collection, leading to a significant decrease in blood donation and hence a decrease in model accuracy. CONCLUSIONS The gradual decrease in future blood donations exhibited by the predictions calls for blood authorities in Zimbabwe to develop interventions that encourage blood donor retention and regular donations. The impact of the Covid-19 pandemic distorted the blood donation patterns such that the developed model did not capture the significant drop in blood donations during the pandemic period. Other shocks such as, a surge in global pandemics and other disasters, will inevitably affect the blood donation system. Thus, forecasting future blood collections with a high degree of accuracy requires robust mathematical models which factor in, the impact of various shocks to the system, on short notice.
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Affiliation(s)
- Coster Chideme
- Department of Mathematical Statistics and Actuarial Sciences, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa.
| | - Delson Chikobvu
- Department of Mathematical Statistics and Actuarial Sciences, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
| | - Tendai Makoni
- Department of Mathematical Statistics and Actuarial Sciences, University of the Free State, P.O. Box 339, Bloemfontein, 9300, South Africa
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Park W, Lee S, Oh MJ, Zhao Q, Kim J, Lee S, Haddadnezhad M, Jung I, Park S. Step-by-Step Nanoscale Top-Down Blocking and Etching Lead to Nanohexapods with Cartesian Geometry. ACS Nano 2024; 18:7402-7410. [PMID: 38411049 DOI: 10.1021/acsnano.3c09844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
In this research, we designed a stepwise synthetic method for Au@Pt hexapods where six elongated Au pods are arranged in a pairwise perpendicular fashion, sharing a common point (the central origin in a Cartesian-coordinate-like hexapod shape), featured with tip-selectively decorated Pt square nanoplates. Au@Pt hexapods were successfully synthesized by applying three distinctive chemical reactions in a stepwise manner. The Pt adatoms formed discontinuous thin nanoplates that selectively covered six concave facets of a Au truncated octahedron and served as etching masks in the succeeding etching process, which prevented underlying Au atoms from being oxidized. The subsequent isotropic etching proceeded radially, starting from the bare Au surface, carving the central nanocrystal in a concave manner. By controlling the etching conditions, Au@Pt hexapods were successfully fabricated, wherein the core Au domain is connected to six protruding arms, which hold Pt nanoplates at the ends. Due to their morphology, Au@Pt hexapods feature distinctive optical properties in the near-infrared region, as a proof of concept, allowing for surface-enhanced Raman spectroscopy (SERS)-based monitoring of in situ CO electrooxidation. We further extended our synthetic library by tailoring the size of the Pt nanoplates and neck widths of Au branches, demonstrating the validity of selective blocking and etching-based colloidal synthesis.
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Affiliation(s)
- Woocheol Park
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Soohyun Lee
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Myeong Jin Oh
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Qiang Zhao
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Jeongwon Kim
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Sungwoo Lee
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | | | - Insub Jung
- Department of Chemistry, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
- Institute of Basic Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Sungho Park
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
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3
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Giffard E, Jannin P, Baxter JSH. A preliminary exploration into top-down and bottom-up deep-learning approaches to localising neuro-interventional point targets in volumetric MRI. Int J Comput Assist Radiol Surg 2024; 19:283-296. [PMID: 37815676 DOI: 10.1007/s11548-023-03023-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 09/12/2023] [Indexed: 10/11/2023]
Abstract
PURPOSE Point localisation is a critical aspect of many interventional planning procedures, specifically representing anatomical regions of interest or landmarks as individual points. This could be seen as analogous to the problem of visual search in cognitive psychology, in which this search is performed either: bottom-up, constructing increasingly abstract and coarse-resolution features over the entire image; or top-down, using contextual cues from the entire image to refine the scope of the region being investigated. Traditional convolutional neural networks use the former, but it is not clear if this is optimal. This article is a preliminary investigation as to how this motivation affects 3D point localisation in neuro-interventional planning. METHODS Two neuro-imaging datasets were collected: one for cortical point localisation for repetitive transcranial magnetic stimulation and the other for sub-cortical anatomy localisation for deep brain stimulation. Four different frameworks were developed using top-down versus bottom-up paradigms as well as representing points as co-ordinates or heatmaps. These networks were applied to point localisation for transcranial magnetic stimulation and subcortical anatomy localisation. These networks were evaluated using cross-validation and a varying number of training datasets to analyse their sensitivity to quantity of training data. RESULTS Each network shows increasing performance as the amount of available training data increases, with the co-ordinate-based top-down network consistently outperforming the others. Specifically, the top-down architectures tend to outperform the bottom-up ones. An analysis of their memory consumption also encourages the top-down co-ordinate based architecture as it requires significantly less memory than either bottom-up architectures or those representing their predictions via heatmaps. CONCLUSION This paper is a preliminary foray into a fundamental aspect of machine learning architectural design: that of the top-down/bottom-up divide from cognitive psychology. Although there are additional considerations within the particular architectures investigated that could affect these results and the number of architectures investigated is limited, our results do indicate that the less commonly used top-down paradigm could lead to more efficient and effective architectures in the future.
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Affiliation(s)
- Enora Giffard
- LTSI - INSERM UMR 1099, Université de Rennes, 35000, Rennes, France
| | - Pierre Jannin
- LTSI - INSERM UMR 1099, Université de Rennes, 35000, Rennes, France
| | - John S H Baxter
- LTSI - INSERM UMR 1099, Université de Rennes, 35000, Rennes, France.
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Schulz R, Bundschuh M, Entling MH, Jungkunst HF, Lorke A, Schwenk K, Schäfer RB. A synthesis of anthropogenic stress effects on emergence-mediated aquatic-terrestrial linkages and riparian food webs. Sci Total Environ 2024; 908:168186. [PMID: 37914130 DOI: 10.1016/j.scitotenv.2023.168186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
Anthropogenic stress alters the linkage between aquatic and terrestrial ecosystems in various ways. Here, we review the contemporary literature on how alterations in aquatic systems through environmental pollution, invasive species and hydromorphological changes carry-over to terrestrial ecosystems and the food webs therein. We consider both the aquatic insect emergence and flooding as pathways through which stressors can propagate from the aquatic to the terrestrial system. We specifically synthesize and contextualize results on the roles of pollutants in the emergence pathway and their top-down consequences. Our review revealed that the emergence and flooding pathway are only considered in isolation and that the overall effects of invasive species or pollutants on food webs at the water-land interface require further attention. While very few recent studies looked at invasive species, a larger number of studies focused on metal transfer compared to pesticides, pharmaceuticals or PCBs, and multiple stress studies up to now left aquatic-terrestrial linkages unconsidered. Recent research on pollutants and emergence used aquatic-terrestrial mesocosms to elucidate the effects of aquatic stressors such as the mosquito control agent Bti, metals or pesticides to understand the effects on riparian spiders. Quality parameters, such as the structural and functional composition of emergent insect communities, the fatty acid profiles, yet also the composition of pollutants transferred to land prove to be important for the effects on riparian spiders. Process-based models including quality of emergence are useful to predict the resulting top-down directed food web effects in the terrestrial recipient ecosystem. In conclusion, we present and recommend a combination of empirical and modelling approaches in order to understand the complexity of aquatic-terrestrial stressor propagation and its spatial and temporal variation.
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Affiliation(s)
- Ralf Schulz
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany.
| | - Mirco Bundschuh
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Martin H Entling
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Hermann F Jungkunst
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Andreas Lorke
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Klaus Schwenk
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Ralf B Schäfer
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
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Mohite V, Prasad S, Mishra RK. Investigating the role of spatial filtering on distractor suppression. Atten Percept Psychophys 2023:10.3758/s13414-023-02831-0. [PMID: 38148431 DOI: 10.3758/s13414-023-02831-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2023] [Indexed: 12/28/2023]
Abstract
In recent years, evidence has accumulated towards a distractor suppression mechanism that enables efficient selection of targets in a visual search task. According to these findings, the search for a target is faster in the presence of a salient distractor in a display among homogenous distractors as opposed to its absence. Studies have also shown that distractor suppression not only operates on the feature level but can also be spatially guided. The motivation of the current study was to examine if spatially guided distractor suppression can be goal-driven. We tested this across four experiments. In Experiment 1A, the task was to search for a shape target (e.g., a circle) and discriminate the orientation of the line within it. In some trials, a salient color distractor was presented in the display while participants were told that it appeared in one of the two locations on the horizontal axis (or the vertical axis, counterbalanced across participants). We expected enhanced distractor suppression when the salient distractor appeared within this "spatial filter" but did not find it since the target was also presented at the filtered locations. Experiment 1B replicated Experiment 1A, except that the target was always presented outside the filter; filtering enhanced search performance. In Experiment 2 even when the filter contained the salient distractor in only 65% of the filtered trials, filtering benefited search performance. In Experiment 3, the filter changed on every trial and did not benefit suppression.
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Affiliation(s)
- Vaishnavi Mohite
- Centre for Neural and Cognitive Sciences, University of Hyderabad, Prof. C R Rao Road, Gachibowli, Hyderabad, Telangana, 500 046, India.
| | - Seema Prasad
- Cognitive Neurophysiology, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Ramesh Kumar Mishra
- Centre for Neural and Cognitive Sciences, University of Hyderabad, Prof. C R Rao Road, Gachibowli, Hyderabad, Telangana, 500 046, India
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Pak V, Hashmi JA. Top-down threat bias in pain perception is predicted by higher segregation between resting-state networks. Netw Neurosci 2023; 7:1248-1265. [PMID: 38144683 PMCID: PMC10631789 DOI: 10.1162/netn_a_00328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 06/23/2023] [Indexed: 12/26/2023] Open
Abstract
Top-down processes such as expectations have a strong influence on pain perception. Predicted threat of impending pain can affect perceived pain even more than the actual intensity of a noxious event. This type of threat bias in pain perception is associated with fear of pain and low pain tolerance, and hence the extent of bias varies between individuals. Large-scale patterns of functional brain connectivity are important for integrating expectations with sensory data. Greater integration is necessary for sensory integration; therefore, here we investigate the association between system segregation and top-down threat bias in healthy individuals. We show that top-down threat bias is predicted by less functional connectivity between resting-state networks. This effect was significant at a wide range of network thresholds and specifically in predefined parcellations of resting-state networks. Greater system segregation in brain networks also predicted higher anxiety and pain catastrophizing. These findings highlight the role of integration in brain networks in mediating threat bias in pain perception.
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Affiliation(s)
- Veronika Pak
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, QC, Canada
| | - Javeria Ali Hashmi
- Department of Anesthesia, Pain Management, and Perioperative Medicine, Nova Scotia Health Authority, Halifax, NS, Canada
- Dalhousie University, Halifax, NS, Canada
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Lakis R, Sauvage FL, Pinault E, Marquet P, Saint-Marcoux F, El Balkhi S. Semi-synthetic human albumin isoforms: Production, structure, binding capacities and influence on a routine laboratory test. Int J Biol Macromol 2023; 250:126239. [PMID: 37572814 DOI: 10.1016/j.ijbiomac.2023.126239] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/02/2023] [Accepted: 08/07/2023] [Indexed: 08/14/2023]
Abstract
Human Serum Albumin (HSA) undergoes Post-Translational-Modifications (PTMs) leading to isoforms affecting its oncotic and non-oncotic properties. HSA is comprised of several isoforms whose abundance may vary with pathologies such as diabetes, kidney and liver diseases. Studying their impact separately may help to understand their sources and potential pathogenicity and further their evaluation as biomarkers. The present study examined semi-synthetic HSA isoforms to investigate independently their structure by means of advanced mass spectrometry techniques (LC-TOF-MS and ICP-MS), influence on the HSA binding/antioxidant activities using a binding capacity test, and potential impact on albumin quantification by a routine immunoturbidimetric assay. Applying different chemical reactions to a commercial HSA solution, we obtained different solutions enriched up to 53 % of native HSA, 78 % of acetylated HSA, 71 % of cysteinylated HSA, 94 % of oxidized HSA, 58 % of nitrosylated HSA and 96 % of glycated HSA, respectively. Moreover, the semi-synthetic isoforms showed differently altered binding capacities for a panel of ligands (Cu, Cd, Au, Ds and L-T4). Furthermore, immunoturbidimetry was found to be insensitive to the presence and abundance of the different isoforms. The fully characterized semi synthetic HSA isoforms obtained should be useful to further investigate their pathogenicity and potential roles as biomarkers.
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Affiliation(s)
- Roy Lakis
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France
| | - François-Ludovic Sauvage
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France
| | - Emilie Pinault
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France
| | - Pierre Marquet
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France; Department of Pharmacology, Toxicology and Pharmacovigilance, CHU Limoges, Limoges, France
| | - Franck Saint-Marcoux
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France; Department of Pharmacology, Toxicology and Pharmacovigilance, CHU Limoges, Limoges, France
| | - Souleiman El Balkhi
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France; Department of Pharmacology, Toxicology and Pharmacovigilance, CHU Limoges, Limoges, France.
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Ortiz-Tudela J, Nicholls VI, Clarke A. Parameters of prediction: Multidimensional characterization of top-down influence in visual perception. Neurosci Biobehav Rev 2023; 153:105369. [PMID: 37619646 PMCID: PMC7615211 DOI: 10.1016/j.neubiorev.2023.105369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/12/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
Despite the recent popularity of predictive processing models of brain function, the term prediction is often instantiated very differently across studies. These differences in definition can substantially change the type of cognitive or neural operation hypothesised and thus have critical implications for the corresponding behavioural and neural correlates during visual perception. Here, we propose a five-dimensional scheme to characterise different parameters of prediction. Namely, flow of information, mnemonic origin, specificity, complexity, and temporal precision. We describe these dimensions and provide examples of their application to previous work. Such a characterisation not only facilitates the integration of findings across studies, but also helps stimulate new research questions.
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Affiliation(s)
- Javier Ortiz-Tudela
- Department of Psychology, Goethe University Frankfurt, Germany; Mind, Brain, and Behavior Research Center, Department of Experimental Psychology, University of Granada, Spain
| | | | - Alex Clarke
- Department of Psychology, University of Cambridge, UK.
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Meehan CE, Schantell M, Springer SD, Wiesman AI, Wolfson SL, O'Neill J, Murman DL, Bares SH, May PE, Johnson CM, Wilson TW. Movement-related beta and gamma oscillations indicate parallels and disparities between Alzheimer's disease and HIV-associated neurocognitive disorder. Neurobiol Dis 2023; 186:106283. [PMID: 37683957 PMCID: PMC10545947 DOI: 10.1016/j.nbd.2023.106283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/02/2023] [Accepted: 09/05/2023] [Indexed: 09/10/2023] Open
Abstract
People with HIV (PWH) often develop HIV-related neurological impairments known as HIV-associated neurocognitive disorder (HAND), but cognitive dysfunction in older PWH may also be due to age-related disorders such as Alzheimer's disease (AD). Discerning these two conditions is challenging since the specific neural characteristics are not well understood and limited studies have probed HAND and AD spectrum (ADS) directly. We examined the neural dynamics underlying motor processing during cognitive interference using magnetoencephalography (MEG) in 22 biomarker-confirmed patients on the ADS, 22 older participants diagnosed with HAND, and 30 healthy aging controls. MEG data were transformed into the time-frequency domain to examine movement-related oscillatory activity and the impact of cognitive interference on distinct stages of motor programming. Both cognitively impaired groups (ADS/HAND) performed significantly worse on the task (e.g., less accurate and slower reaction time) and exhibited reductions in frontal and cerebellar beta and parietal gamma activity relative to controls. Disease-specific aberrations were also detected such that those with HAND exhibited weaker gamma interference effects than those on the ADS in frontoparietal and motor areas. Additionally, temporally distinct beta interference effects were identified, with ADS participants exhibiting stronger beta interference activity in the temporal cortex during motor planning, along with weaker beta interference oscillations dispersed across frontoparietal and cerebellar cortices during movement execution relative to those with HAND. These results indicate both overlapping and distinct neurophysiological aberrations in those with ADS disorders or HAND in key motor and top-down cognitive processing regions during cognitive interference and provide new evidence for distinct neuropathology.
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Affiliation(s)
- Chloe E Meehan
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA
| | - Mikki Schantell
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA; College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Seth D Springer
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA; College of Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Alex I Wiesman
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | | | - Jennifer O'Neill
- Department of Internal Medicine, Division of Infectious Diseases, UNMC, Omaha, NE, USA
| | - Daniel L Murman
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, USA; Memory Disorders & Behavioral Neurology Program, UNMC, Omaha, NE, USA
| | - Sara H Bares
- Department of Internal Medicine, Division of Infectious Diseases, UNMC, Omaha, NE, USA
| | - Pamela E May
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | | | - Tony W Wilson
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE, USA; Department of Pharmacology & Neuroscience, Creighton University, Omaha, NE, USA.
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Rahali MA, Lakis R, Sauvage FL, Pinault E, Marquet P, Saint-Marcoux F, El Balkhi S. Posttranslational-modifications of human-serum-albumin analysis by a top-down approach validated by a comprehensive bottom-up analysis. J Chromatogr B Analyt Technol Biomed Life Sci 2023; 1224:123740. [PMID: 37182409 DOI: 10.1016/j.jchromb.2023.123740] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/03/2023] [Accepted: 05/05/2023] [Indexed: 05/16/2023]
Abstract
The posttranslational modifications (PTM) of human serum albumin (HSA) can result in the development of isoforms that have been identified as potential biomarkers for advanced hepatic diseases. However, previous approaches using top-down (TD) analysis to identify isoforms based on molecular weight may have resulted in misidentifications. The nature of the identified isoforms has never been confirmed in previous works. Here, we aimed to critically evaluate TD for the characterization and determination of HSA isoforms in patients and make an inventory of HSA-PTM. Serum samples from control subjects and patients with liver dysfunctions were analyzed using both top-down (TD) and bottom-up (BU) approaches. TD analysis involved using a LC-TOF-MS system to obtain a multicharged spectrum of HSA, which was deconvoluted to identify isoforms. Spectra were then used for relative quantitation analysis of albumin isoform abundances based on trapezoidal integration. For BU analysis, serums were reduced +/- alkylated, digested with trypsin and analyzed in the Q-TOF, data-dependent acquisition (DDA) mode to generate a SWATH-MS high-resolution mass spectral library of all HSA peptides. Tryptic digests of another set of serum samples were then analyzed using data-independent acquisition (DIA) mode to confirm the presence of HSA isoforms and their modification sites. TD detected 15 isoforms corresponding to various modifications, including glycation, cysteinylation, nitrosylation, and oxidation (di- and tri-). In BU, the spectral library containing 127 peptides allowed for the characterization of the important isoforms with their modified sites, including some modifications that were only characterized in BU (carbamylation, deamidation, and amino-acid substitution). The method used for determining isoforms offered acceptable reproducibility (intra-/inter-assay CVs < 15%) for all isoforms present at relative abundances higher than 2%. Overall, the study found that several isoforms could be missed or misidentified by TD. However, all HSA isoforms identified by TD and reported to be relevant in liver dysfunctions were confirmed by BU. This critical evaluation of TD approach helped design an adequate and reliable method for the characterization of HSA isoforms in patients and offers the possibility to estimate isoform abundances within 3 min. These findings have significant implications for the diagnosis and treatment of liver dysfunctions.
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Affiliation(s)
- Mohamad-Ali Rahali
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France
| | - Roy Lakis
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France
| | - François-Ludovic Sauvage
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France
| | - Emilie Pinault
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France
| | - Pierre Marquet
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France; Department of pharmacology, toxicology and pharmacovigilance, CHU Limoges, Limoges, France
| | - Franck Saint-Marcoux
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France; Department of pharmacology, toxicology and pharmacovigilance, CHU Limoges, Limoges, France
| | - Souleiman El Balkhi
- P&T, UMR1248, University of Limoges, National Institute for Health and Medical Research (INSERM), Limoges, France; Department of pharmacology, toxicology and pharmacovigilance, CHU Limoges, Limoges, France.
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Becker SI, Grubert A, Horstmann G, Ansorge U. Which processes dominate visual search: Bottom-up feature contrast, top-down tuning or trial history? Cognition 2023; 236:105420. [PMID: 36905828 DOI: 10.1016/j.cognition.2023.105420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/11/2023]
Abstract
Previous research has identified three mechanisms that guide visual attention: bottom-up feature contrasts, top-down tuning, and the trial history (e.g., priming effects). However, only few studies have simultaneously examined all three mechanisms. Hence, it is currently unclear how they interact or which mechanisms dominate over others. With respect to local feature contrasts, it has been claimed that a pop-out target can only be selected immediately in dense displays when the target has a high local feature contrast, but not when the displays are sparse, which leads to an inverse set-size effect. The present study critically evaluated this view by systematically varying local feature contrasts (i.e., set size), top-down knowledge, and the trial history in pop-out search. We used eye tracking to distinguish between early selection and later identification-related processes. The results revealed that early visual selection was mainly dominated by top-down knowledge and the trial history: When attention was biased to the target feature, either by valid pre-cueing (top-down) or automatic priming, the target could be localised immediately, regardless of display density. Bottom-up feature contrasts only modulated selection when the target was unknown and attention was biased to the non-targets. We also replicated the often-reported finding of reliable feature contrast effects in the mean RTs, but showed that these were due to later, target identification processes (e.g., in the target dwell times). Thus, contrary to the prevalent view, bottom-up feature contrasts in dense displays do not seem to directly guide attention, but only facilitate nontarget rejection, probably by facilitating nontarget grouping.
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Forstinger M, Ansorge U. Evidence for top-down suppression of negative features in the target feature dimension. Cognition 2023; 235:105415. [PMID: 36827730 DOI: 10.1016/j.cognition.2023.105415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 01/23/2023] [Accepted: 02/14/2023] [Indexed: 02/24/2023]
Abstract
While searching for a goal-relevant object, an internal representation of the features necessary to identify the to-be-searched-for object (i.e., target) guides attention towards visual stimuli with matching properties. Recent evidence suggests that features that negatively define a target (i.e., negative features) also bias attentional allocation through top-down suppression. Since humans usually know what to look for, it will rarely, if ever, be the case that a negative feature defines a goal-relevant object alone. Thus, to better understand the relevance of top-down suppression, our participants searched for a target conjunctively defined by a positive (e.g., a blue bar) and a negative feature (e.g., a nonred bar) with both features realized within the same dimension (color in Experiments 1, 3 and 4, orientation in Experiment 2). Experiments 1 and 2 showed that reaction times were slower if cues with a negative feature preceded the target at the same versus a different position (i.e., validly vs. invalidly cued targets), indicating suppression. In contrast, cues with a task-irrelevant different-dimension feature elicited no significant reaction time difference between validly cued and invalidly cued trials. In addition, Experiment 3 showed that while negative cues were top-down suppressed, cues with a positive feature captured attention. This finding indicated that both positive and negative features guide visual attention through capture and suppression, respectively, during the search for a target defined by the presence of one and the absence of another feature from the same dimension. However, suppression seems to apply to the negative and all nontarget features in the task-relevant dimension. This was shown in Experiment 4, in which participants suppressed cues with a task-irrelevant color similarly to cues with a negative color.
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Affiliation(s)
- Marlene Forstinger
- Department of Cognition, Emotion, and Methods in Psychology, University of Vienna, Austria.
| | - Ulrich Ansorge
- Department of Cognition, Emotion, and Methods in Psychology, University of Vienna, Austria; Vienna Cognitive Science Hub, University of Vienna, Austria; Research Platform Mediatised Lifeworlds, University of Vienna, Austria
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13
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Lin Y, Agarwal AM, Anderson LC, Marshall AG. Discovery of a biomarker for β-Thalassemia by HPLC-MS and improvement from Proton Transfer Reaction - Parallel Ion Parking. J Mass Spectrom Adv Clin Lab 2023; 28:20-26. [PMID: 36814695 PMCID: PMC9939715 DOI: 10.1016/j.jmsacl.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 02/05/2023] Open
Abstract
β-thalassemia is a quantitative hemoglobin (Hb) disorder resulting in reduced production of Hb A and increased levels of Hb A2. Diagnosis of β-thalassemia can be problematic when combined with other structural Hb variants, so that the separation approaches in routine clinical centers are not sufficiently decisive to obtain accurate results. Here, we separate the intact Hb subunits by high-performance liquid chromatography, followed by top-down tandem mass spectrometry of intact subunits to distinguish Hb variants. Proton transfer reaction-parallel ion parking (PTR-PIP), in which a radical anion removes protons from multiply charged precursor ions and produces charge-reduced ions spanning a limited m/z range, was used to increase the signal-to-noise ratio of the subunits of interest. We demonstrate that the δ/β ratio can act as a biomarker to identify β-thalassemia in normal electrospray ionization MS1 and PTR-PIP MS1. The application of PTR-PIP significantly increases the sensitivity and specificity of the HPLC-MS method to identify δ/β ratio as a thalassemia biomarker.
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Key Words
- ACN, Acetonitrile
- AUC, Areas under the curve
- CID, Collision-induced dissociation
- ESI, Electrospray ionization
- ETD, Electron-transfer dissociation
- FA, Formic acid
- FN, False-negative
- FP, False-positive
- FT-ICR
- FT-ICR, MS Fourier transform ion cyclotron resonance mass spectrometer
- FTMS
- Fourier transform ion cyclotron resonance
- Hb A, Normal adult Hb
- Hb, Hemoglobin
- HbA1d, Hb β with glutathione
- IFCC, International Federation of Clinical Chemistry and Laboratory Medicine
- IQR, Interquartile range
- J, Youden Index
- MCW, Methanol/chloroform/water
- MS, Mass spectrometry
- PTM, Post-translational modification
- PTR-PIP, Proton transfer reaction-parallel ion parking
- ROC, Receiver operating characteristic
- S/N, Signal-to-noise ratios
- Se(c), Sensitivity, the probability of a true positive)
- Sp(c), Specificity, the probability of a true negative)
- TIC, Total ion chromatogram
- TN, True negative
- TP, True positive
- Top-down
- XIC, Extracted ion chromatograms
- m/z, Mass-to-charge ratios
- δ/β ratio
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Affiliation(s)
- Yuan Lin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32308, United States
| | - Archana M. Agarwal
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132, United States,ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT 84108, United States
| | - Lissa C. Anderson
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, United States,Corresponding authors at: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32308, United States (A.G. Marshall).
| | - Alan G. Marshall
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32308, United States,Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, United States,Corresponding authors at: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32308, United States (A.G. Marshall).
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Cochrane BA, Pratt J, Milliken B. Top-down then automatic: Instructions can continue to influence visual search when no longer actively implemented. Atten Percept Psychophys 2023; 85:76-87. [PMID: 36045313 DOI: 10.3758/s13414-022-02558-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2022] [Indexed: 01/10/2023]
Abstract
The present study investigated the automaticity of top-down instructions in visual search when the instruction was no longer actively implemented. To do so, we exploited the Priming of Pop-out (PoP) effect, a selection history phenomenon that reflects faster responses when the target and distractor colors are repeated than switched across trials of singleton search. We then had participants perform a color singleton search task where they implemented the instruction of imagining the opposite color of the previous target, which put the target colors underlying PoP and the imagery instruction in opposition. To assess automaticity, on some trials participants were instructed to stop implementing the imagery instruction. When the imagery instruction was implemented, responses were faster when the target and distractor colors switched (i.e., imagery congruent) than repeated (i.e., imagery incongruent) across search displays - a pattern of results opposite to the PoP effect. When participants were to not implement this instruction, the PoP effect was absent, indicating the imagery instruction had a lingering influence on visual search. This remained true even when participants reported successfully not implementing the instruction, and only when the imagery abandonment instruction was supplanted by a different top-down task was the lingering influence removed such that the PoP effect returned. Overall, the present study demonstrates that top-down instructions can continue to influence visual search despite the will of the observer.
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15
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Lignieres L, Legros V, Khelil M, Senecaut N, Lauber MA, Camadro JM, Chevreux G. Capillary liquid chromatography coupled with mass spectrometry for analysis of nanogram protein quantities on a wide-pore superficially porous particle column in top-down proteomics. J Chromatogr B Analyt Technol Biomed Life Sci 2023; 1214:123566. [PMID: 36516651 DOI: 10.1016/j.jchromb.2022.123566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 12/01/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
Abstract
In top-down proteomics experiments, intact protein ions are subjected to gas-phase fragmentation for MS analysis without prior digestion. This approach is used to characterize post-translational modifications and clipped forms of proteins, avoids several "inference" problems associated with bottom-up proteomics, and is well suited to the study of proteoforms. In the past decade, top-down proteomics has progressed rapidly, taking advantage of MS instrumentation improvements and the efforts of pioneering groups working to improve sample handling and data processing. The potential of this technology has been established through its successful use in a number of important biological studies. However, many challenges remain to be addressed like improving protein separation capabilities such that it might become possible to expand the dynamic range of whole proteome analysis, address co-elution and convoluted mass spectral data, and aid final data processing from peak identification to quantification. In this study, we investigated the use of a wide-pore silica-based superficially porous media with a high coverage phenyl bonding, commercially packed into customized capillary columns for the purpose of top-down proteomics. Protein samples of increasing complexity were tested, namely subunit digests of a monoclonal antibody, components of purified histones and proteins extracted from eukaryotic ribosomes. High quality mass spectra were obtained from only 100 ng of protein sample while using difluoroacetic acid as an ion pairing agent to improve peak shape and chromatographic resolution. A peak width at half height of about 15 s for a 45 min gradient time was observed on a complex mixture giving an estimated peak capacity close to 100. Most importantly, efficient separations were obtained for highly diverse proteins and there was no need to make method specific adjustments, suggesting this is a highly versatile and easy-to-use setup for top-down proteomics.
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Affiliation(s)
- Laurent Lignieres
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Véronique Legros
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Manel Khelil
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Nicolas Senecaut
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Matthew A Lauber
- Waters Corporation, 34, Maple Street, Milford, MA 01757-3696, United States
| | | | - Guillaume Chevreux
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France.
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16
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Yang Y, Sha L, Zhao H, Guo Z, Wu M, Lu P. Recent advances in cellulose microgels: Preparations and functionalized applications. Adv Colloid Interface Sci 2023; 311:102815. [PMID: 36427465 DOI: 10.1016/j.cis.2022.102815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/02/2022] [Accepted: 11/15/2022] [Indexed: 11/20/2022]
Abstract
Microgels are soft, deformable, permeable, and stimuli-responsive microscopic polymeric particles that are now emerging as prospective multifunctional soft materials for delivery systems, interface stabilization, cell cultures and tissue engineering. Cellulose microgels are emerging biopolymeric microgels with unique characteristics such as abound hydroxyl structure, admirable designability, multiscale pore network and excellent biocompatibility. This review summarizes the fabrication strategies for microgel, then highlights the fabrication routes for cellulose microgels, and finally elaborates cellulose microgels' bright application prospects with unique characteristics in the fields of controlled release, interface stabilization, coating, purification, nutrition/drug delivery, and bio-fabrication. The challenges to be addressed for further applications and considerable scope for development in future of cellulose microgels are also discussed.
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Affiliation(s)
- Yang Yang
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Lishan Sha
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Han Zhao
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Zhaojun Guo
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Min Wu
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China
| | - Peng Lu
- College of Light Industry and Food Engineering, Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control, Guangxi University, Nanning, Guangxi 530004, China.
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17
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Zhang B, Brascamp JW. Modest effect of knowledge on bistable perception of structure-from-motion. Vision Res 2022; 201:108118. [PMID: 36058203 DOI: 10.1016/j.visres.2022.108118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 01/25/2023]
Abstract
When faced with ambiguous visual input, observers may experience various perceptual interpretations of the same input. Indeed, such input can cause perception to unpredictably switch between interpretations over time. Theories of such so-called multistable perception broadly fall into two categories: top-down theories that emphasize dependence on higher-level cognitive factors such as knowledge, and bottom-up theories that suggest more vital involvement of aspects of lower-order information processing such as adaptation in the visual system. Most present-day accounts hold that both factors play a role, so that perceptual reversals arise inevitably due to factors like adaptation, yet can be delayed or hastened by higher-level cognitive influences. We revisited a body of work that shows the occurrence of perceptual reversals to depend dramatically on the observer's knowledge that the input is, indeed, ambiguous: without such knowledge many observers in that work did not experience any reversals, in apparent conflict with the idea that reversals are inevitable. We used an ambiguous animation that allowed subjects to report perceptual reversals without realizing the ambiguity. We found that subjects who were aware of the animation's ambiguity reported slightly more perceptual reversals than uninformed subjects, but that this between-group difference was small, and was overshadowed by inter-observer variability within each group. These findings suggest that knowledge of ambiguity can influence perception of ambiguous stimuli, but only mildly, in keeping with most present-day accounts. We discuss potential explanations for the discrepancy with the earlier work.
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Affiliation(s)
- Bobicheng Zhang
- Department of Psychology, Michigan State University, 316 Physics Rd, East Lansing 48823, MI, United States.
| | - Jan W Brascamp
- Department of Psychology, Michigan State University, 316 Physics Rd, East Lansing 48823, MI, United States.
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18
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Gallant SN, Kennedy BL, Bachman SL, Huang R, Cho C, Lee TH, Mather M. Behavioral and fMRI evidence that arousal enhances bottom-up selectivity in young but not older adults. Neurobiol Aging 2022; 120:149-166. [PMID: 36198230 PMCID: PMC9805381 DOI: 10.1016/j.neurobiolaging.2022.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 01/03/2023]
Abstract
The locus coeruleus-noradrenergic system integrates signals about arousal states throughout the brain and helps coordinate cognitive selectivity. However, age-related changes in this system may impact how arousal coordinates selectivity in older adults. To examine this, we compared how increases in emotional arousal modulates cognitive selectivity for images differing in perceptual salience in young and older adults. Using functional magnetic resonance imaging, we found that relative to older adults, hearing an arousing sound enhanced young adults' bottom-up processing and incidental memory for high versus low salience category-selective body images. We also examined how arousing sounds impacted a top-down goal to detect dot-probes that appeared immediately after high or low salience images. We found that young adults were slower to detect probes appearing after high salience body images on arousing trials, whereas older adults showed this pattern on non-arousing trials. Taken together, our findings show that arousal's effect on selectivity changes with age and differs across bottom-up and top-down processing.
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Affiliation(s)
- Sara N. Gallant
- Davis School of Gerontology, University of Southern California, Los Angeles, CA
| | - Briana L. Kennedy
- School of Psychological Science, University of Western Australia, Perth, Australia
| | - Shelby L. Bachman
- Davis School of Gerontology, University of Southern California, Los Angeles, CA
| | - Ringo Huang
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA
| | - Christine Cho
- Davis School of Gerontology, University of Southern California, Los Angeles, CA
| | - Tae-Ho Lee
- Department of Psychology, Virginia Tech, Blacksburg, VA, United States
| | - Mara Mather
- Davis School of Gerontology, University of Southern California, Los Angeles, CA
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Brodbelt JS. Deciphering combinatorial post-translational modifications by top-down mass spectrometry. Curr Opin Chem Biol 2022; 70:102180. [PMID: 35779351 PMCID: PMC9489649 DOI: 10.1016/j.cbpa.2022.102180] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 12/15/2022]
Abstract
Post-translational modifications (PTMs) create vast structural and functional diversity of proteins, ultimately modulating protein function and degradation, influencing cellular signaling, and regulating transcription. The combinatorial patterns of PTMs increase the heterogeneity of proteins and further mediates their interactions. Advances in mass spectrometry-based proteomics have resulted in identification of thousands of proteins and allowed characterization of numerous types and sites of PTMs. Examination of intact proteins, termed the top-down approach, offers the potential to map protein sequences and localize multiple PTMs on each protein, providing the most comprehensive cataloging of proteoforms. This review describes some of the dividends of using mass spectrometry to analyze intact proteins and showcases innovative strategies that have enhanced the promise of top-down proteomics for exploring the impact of combinatorial PTMs in unsurpassed detail.
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Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
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20
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Trapp S, Guitart-Masip M, Schröger E. A link between age, affect, and predictions? Eur J Ageing 2022; 19:945-952. [PMID: 36692760 PMCID: PMC9729523 DOI: 10.1007/s10433-022-00710-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2022] [Indexed: 01/26/2023] Open
Abstract
The prevalence of depressive symptoms decreases from late adolescence to middle age adulthood. Furthermore, despite significant losses in motor and cognitive functioning, overall emotional well-being tends to increase with age, and a bias to positive information has been observed multiple times. Several causes have been discussed for this age-related development, such as improvement in emotion regulation, less regret, and higher socioeconomic status. Here, we explore a further explanation. Our minds host mental models that generate predictions about forthcoming events to successfully interact with our physical and social environment. To keep these models faithful, the difference between the predicted and the actual event, that is, the prediction error, is computed. We argue that prediction errors are attenuated in the middle age and older mind, which, in turn, may translate to less negative affect, lower susceptibility to affective disorders, and possibly, to a bias to positive information. Our proposal is primarily linked to perceptual inferences, but may hold as well for higher-level, cognitive, and emotional forms of error processing.
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Affiliation(s)
- Sabrina Trapp
- grid.434949.70000 0001 1408 3925Macromedia University of Applied Sciences, Munich, Germany ,grid.4714.60000 0004 1937 0626Aging Research Center, Karolinska Institutet, 17165 Stockholm, Sweden
| | - Marc Guitart-Masip
- grid.4714.60000 0004 1937 0626Aging Research Center, Karolinska Institutet, 17165 Stockholm, Sweden ,grid.467087.a0000 0004 0442 1056Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Stockholm, Sweden ,grid.83440.3b0000000121901201Max Planck University College London Centre for Computational Psychiatry and Ageing Research, University College London, London, WC1B 5EH UK ,grid.9647.c0000 0004 7669 9786Wilhelm Wundt Institute for Psychology, Leipzig University, Leipzig, Germany
| | - Erich Schröger
- grid.4714.60000 0004 1937 0626Aging Research Center, Karolinska Institutet, 17165 Stockholm, Sweden ,grid.9647.c0000 0004 7669 9786Wilhelm Wundt Institute for Psychology, Leipzig University, Leipzig, Germany
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DelGuidice CE, Ismaiel OA, Mylott WR, Yuan M, Halquist MS. Intact quantitative bioanalytical method development and fit-for-purpose validation of a monoclonal antibody and its related fab fragment in human vitreous and aqueous humor using LC-HRMS. Anal Bioanal Chem 2022; 414:4189-4202. [PMID: 35451621 DOI: 10.1007/s00216-022-04071-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 03/27/2022] [Accepted: 04/06/2022] [Indexed: 11/29/2022]
Abstract
Ranibizumab is an FDA-approved drug used to treat wet age-related macular degeneration (AMD), diabetic retinopathy, macular edema, and myopic choroidal neovascularization. Bevacizumab is another drug often used off-label to treat wet AMD. In order to reduce unwanted angiogenesis, ranibizumab and bevacizumab target circulating VEGF-A in the eye. Concentration levels in human vitreous and aqueous humor can be used to provide valuable efficacy information. However, vitreous and aqueous humor's aqueous environment, and vitreous humor's viscosity, as well as the stickiness of the analytes can provide bioanalytical challenges. In this manuscript, we describe the development, optimization, and fit-for-purpose validation of an LC-HRMS method designed for intact quantitative bioanalysis of ranibizumab and bevacizumab in human vitreous and aqueous humor following intravitreal administration. In order to fully develop this method, evaluations were conducted to optimize the conditions, including the data processing model (extracted ion chromatograms (XICs) vs deconvolution), carryover mitigation, sample preparation scheme optimization for surrogate and primary matrices, use of internal standard/immunocapture/deglycosylation, and optimization of the extraction and dilution procedure, as well as optimization of the liquid chromatography and mass spectrometry conditions. Once the method was fully optimized, a fit-for-purpose validation was conducted, including matrix parallelism, with a linear calibration range of 10 to 200 µg/mL. The development of this intact quantitative method using LC-HRMS provides a proof-of-concept template for challenging, but valuable new and exciting bioanalytical techniques.
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Affiliation(s)
- Catherine E DelGuidice
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA. .,PPD Laboratories, Richmond, VA, USA.
| | - Omnia A Ismaiel
- Department of Analytical Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | | | | | - Matthew S Halquist
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
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22
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Caras ML, Happel MFK, Chandrasekaran B, Ripollés P, Keesom SM, Hurley LM, Remage-Healey L, Holt LL, Wright BA. Non-sensory Influences on Auditory Learning and Plasticity. J Assoc Res Otolaryngol 2022. [PMID: 35235100 DOI: 10.1007/s10162-022-00837-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/30/2021] [Indexed: 10/19/2022] Open
Abstract
Distinguishing between regular and irregular heartbeats, conversing with speakers of different accents, and tuning a guitar-all rely on some form of auditory learning. What drives these experience-dependent changes? A growing body of evidence suggests an important role for non-sensory influences, including reward, task engagement, and social or linguistic context. This review is a collection of contributions that highlight how these non-sensory factors shape auditory plasticity and learning at the molecular, physiological, and behavioral level. We begin by presenting evidence that reward signals from the dopaminergic midbrain act on cortico-subcortical networks to shape sound-evoked responses of auditory cortical neurons, facilitate auditory category learning, and modulate the long-term storage of new words and their meanings. We then discuss the role of task engagement in auditory perceptual learning and suggest that plasticity in top-down cortical networks mediates learning-related improvements in auditory cortical and perceptual sensitivity. Finally, we present data that illustrates how social experience impacts sound-evoked activity in the auditory midbrain and forebrain and how the linguistic environment rapidly shapes speech perception. These findings, which are derived from both human and animal models, suggest that non-sensory influences are important regulators of auditory learning and plasticity and are often implemented by shared neural substrates. Application of these principles could improve clinical training strategies and inform the development of treatments that enhance auditory learning in individuals with communication disorders.
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Abid N, Khan AM, Shujait S, Chaudhary K, Ikram M, Imran M, Haider J, Khan M, Khan Q, Maqbool M. Synthesis of nanomaterials using various top-down and bottom-up approaches, influencing factors, advantages, and disadvantages: A review. Adv Colloid Interface Sci 2022; 300:102597. [PMID: 34979471 DOI: 10.1016/j.cis.2021.102597] [Citation(s) in RCA: 89] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/07/2021] [Accepted: 12/25/2021] [Indexed: 12/25/2022]
Abstract
Nanotechnology is one of the emerging fields of the 21st Century. Many new devices and patentable technology is based on nanomaterials (NMs). One of the dominant factors in the use of nanomaterials and their applications in various fields is the synthesis and growth mechanism of nanostructures and nanomaterials. A nanostructured material may have been a good candidate in one application but could be more useful in a different application if synthesized by a different mechanism and technique. Similarly, the structure and morphology of a nanomaterial also depend upon the method of growth and synthesis. For example, it is easy to grow and synthesize amorphous nanostructured thin film using the plasma magnetron sputtering technique, but it may be difficult to obtain a similar structure using the thermal evaporation process due to the nature of the technique itself. In this study, the Top-down and Bottom-up methods and techniques of synthesizing nanostructured materials are reviewed, compared, and analyzed. Both approaches are critically analyzed, and the influencing factors on the synthesis of different nanomaterials, the advantages, and disadvantages of each technique are reported. This review also provides a step-by-step analysis of the choice of method for the synthesis of namomaterials for specific applications.
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Affiliation(s)
- Namra Abid
- Physics Department, Lahore Garrison University, Lahore 54000, Punjab, Pakistan
| | - Aqib Muhammad Khan
- Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, 14 Ali Road, Lahore, Pakistan
| | - Sara Shujait
- Physics Department, Lahore Garrison University, Lahore 54000, Punjab, Pakistan
| | - Kainat Chaudhary
- Physics Department, Lahore Garrison University, Lahore 54000, Punjab, Pakistan
| | - Muhammad Ikram
- Solar Cell Application Research Lab, Department of Physics, Government College University Lahore, Lahore 54000, Punjab, Pakistan.
| | - Muhammad Imran
- State Key Laboratory of Chemical Resource Engineering, Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing Engineering Centre for Hierarchical Catalysts, Beijing University of Chemical Technology, Beijing 100029, China
| | - Junaid Haider
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Maaz Khan
- Nanomaterials Research Group, Physics Division, PINSTECH, Islamabad, Pakistan
| | - Qasim Khan
- Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, Guangdong 518000, China.
| | - Muhammad Maqbool
- Department of Clinical & Diagnostic Sciences, Health Physics Program, the University of Alabama at Birmingham, USA.
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24
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Abstract
Protein encoding genes can undergo modifications posttranscriptionally and posttranslationally, yielding many different "proteoforms." The chemical diversity of such modifications is known to be important biomarkers of function within biological systems but is not completely understood. Top-down mass spectrometry is a valuable tool for the characterization of proteoforms, especially for histones that have complex combinations of posttranslational modifications (PTMs). In this chapter, we present a top-down liquid chromatography-mass spectrometry experimental and data analysis workflow for the identification of novel, unexpected modifications on histones. Proteoforms of interest are first discovered using the "open" modification search in TopPIC. Then target proteoforms are manually confirmed using the data visualization tool-LcMsSpectator, part of the Informed-Proteomics package. The workflow can be very helpful in targeted PTM analysis and can be expanded to other types of proteins for discovery of unknown PTMs.
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Affiliation(s)
- Jesse W Wilson
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Mowei Zhou
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA.
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25
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Abstract
Wastewater-based epidemiology (WBE) has become popular to estimate the use of drugs of abuse and recently to establish the incidence of CoVID 19 in large cities. However, its possibilities have been expanded recently as a technique that allows to establish a fingerprint of the characteristics of a city, such as state of health/disease, healthy/unhealthy living habits, exposure to different types of contaminants, etc. with respect to other cities. This has been thanks to the identification of human biomarkers as well as to the fingerprinting and profiling of the characteristics of the wastewater catchment that determine these circumstances. The purpose of this review is to analyze the different methodological schemes that have been developed to perform this biomarker identification as well as the most characteristic analytical techniques in each scheme, their advantages and disadvantages and the knowledge gaps identified. We also discussed the future scope for development.
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Affiliation(s)
- Yolanda Picó
- Environmental and Food Safety Research Group of the University of Valencia (SAMA-UV), Desertification Research Centre (CIDE), CSIC-GV-UV, Moncada Naquera Road Km 4.3, 46113 Moncada, Valencia, Spain,Corresponding author
| | - Damià Barceló
- Department of Environmental Chemistry, IDAEA-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain,Catalan Institute for Water Research, ICRA – CERCA, Technological Park of the University of Girona, Emili Grahit 101, 17003 Girona, Spain
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26
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Li B, Ho SSH, Li X, Guo L, Chen A, Hu L, Yang Y, Chen D, Lin A, Fang X. A comprehensive review on anthropogenic volatile organic compounds (VOCs) emission estimates in China: Comparison and outlook. Environ Int 2021; 156:106710. [PMID: 34144364 DOI: 10.1016/j.envint.2021.106710] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/31/2021] [Accepted: 06/08/2021] [Indexed: 06/12/2023]
Abstract
Accurate measurement and estimation on the trends and spatial distributions of VOCs emissions in China are critical to establishing efficient local or regional pollution control measures, while less is known about the discrepancies on VOCs emissions estimated by previous studies. In this study, two of the estimation approaches including the bottom-up and top-down methods have been reviewed with the data collected from many studies. The approaches demonstrated that the total anthropogenic VOCs emissions in China have been increasing since 1949. The contributions of industrial and solvent use to total VOCs emissions have been increasing since 2000, whereas the contributions of transportation sector have shown a decreasing trend since 2000. The contributions of fuel combustion have also been decreasing since 1950. The gaps of emission estimates for the industry and solvent use were 99.3 ± 22.7% and 81.5 ± 41.8%, respectively, which distributed in much wider ranges than other sources (e.g. 28.9 ± 16.7% for fuel combustion). In comparison to the top-down method, larger variations on the annual VOCs emission estimates were seen using the bottom-up method that comprised different data sources. For the view of spatial pattern, most hot emission estimate spots were concentrated in the eastern China, consistent to their relatively stronger strengths in the industrialization and urbanization. Although the total VOCs emission in China has been continuously increasing during 2008-2016, the VOCs emissions per gross domestic production (GDP) showed a decreasing trend. As for individual compounds, large discrepancy was seen on formaldehyde, with the coefficient of variation (CV) ranged from 37% to 128% over the years. In overall of view, the importance of industrial process and solvent use is increasing. More focuses must be made to these two sources. Emissions of individual compound, particularly those of oxygenated VOCs, were not completely determined and should be better quantified.
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Affiliation(s)
- Bowei Li
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Steven Sai Hang Ho
- Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada, USA
| | - Xinhe Li
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Liya Guo
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ao Chen
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Liting Hu
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yang Yang
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Di Chen
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Anan Lin
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xuekun Fang
- College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center for Global Change Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
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27
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He H, Chen Y, Li X, Hu X, Wang J, Wu T, Yang D, Guan Q. Decline in the integration of top-down and bottom-up attentional control in older adults with mild cognitive impairment. Neuropsychologia 2021; 161:108014. [PMID: 34478757 DOI: 10.1016/j.neuropsychologia.2021.108014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/27/2021] [Accepted: 08/27/2021] [Indexed: 11/23/2022]
Abstract
Individuals with mild cognitive impairment (MCI) have deficits in goal-directed top-down and stimulus-driven bottom-up attentional control. However, it remains unclear whether and how the interaction between the two processes is altered in individuals with MCI. We collected electroencephalography (EEG) data from 30 older adults with MCI and 30 demographically matched healthy controls (HCs) when they were performing a perceptual decision-making task, in which we manipulated the cognitive load involved in task-relevant top-down processing and the surprise level involved in task-irrelevant bottom-up processing. We found the significant group difference in the interaction between top-down and bottom-up processes. HCs showed enlarged P3 and strengthened event-related microstate C on high (vs. low) surprise level trials under high cognitive load, while there was no such surprise effect suggesting distraction under low cognitive load. In contrast, participants with MCI showed increased P2 and P3 amplitudes and strengthened microstates C and D on high (vs. low) surprise level trials under low cognitive load yet no surprise effect under high load. These results suggested that participants with MCI were distracted by task-irrelevant information under low cognitive load, while under high load, they might experience a passive inhibition on the task-irrelevant bottom-up processing because of the exhaustion of attentional resources; in addition, this altered interaction observed in the MCI group occurred at the stages of selective attention and uncertainty reduction.
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Affiliation(s)
- Hao He
- Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China; Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China
| | - Yiqi Chen
- Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China; Department of Psychology, University of Mannheim, Mannheim, Germany
| | - Xiaoyu Li
- Department of Science and Technology, Shenzhen University, Shenzhen, China
| | - Xiaohui Hu
- Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China
| | - Jing Wang
- Sichuan Provincial Center for Mental Health, Center of Psychosomatic Medicine of Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Tiantian Wu
- Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China
| | - Dandan Yang
- Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China
| | - Qing Guan
- Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China; Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China.
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28
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Hamidli N, Andrasi M, Nagy C, Gaspar A. Analysis of intact proteins with capillary zone electrophoresis coupled to mass spectromery using uncoated and coated capillaries. J Chromatogr A 2021; 1654:462448. [PMID: 34392123 DOI: 10.1016/j.chroma.2021.462448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/28/2021] [Accepted: 07/28/2021] [Indexed: 10/20/2022]
Abstract
Although, in general, the application of coated capillaries is recommended for the separation of intact proteins, bare silica capillary is still the most often used capillary due to its simplicity and cheapness. In this work, the performance of bare fused silica capillary for intact protein analysis was compared to that of different (dynamically coated polybrene (PB) and permanently coated linear polyacrylamide (LPA)) coated capillaries using capillary zone electrophoresis - mass spectrometry (CZE-MS). In cases where low pH (pH=1.8) was used in bare silica capillaries, good precision (0.56-0.78 RSD% and 1.7-6.5 RSD% for migration times and peak areas, respectively), minimal adsorption and separation efficiency (N= 27 000/m - 322 000/m) similar to or even better than those obtained with the coated capillaries (created by an intricate multi-step process) was achieved. The PB and the LPA capillaries demonstrated their slightly better resolving power in terms of separating the different forms/variants of the same protein (e.g., hemoglobin subunits). Among the studied capillaries the one with LPA coating showed the most stable separations in the long term (n=25: 0.18-0.49 RSD% and 3.1-4.9 RSD% for migration times and peak areas, respectively). For the separation of a few proteins or even a larger number of proteins in biological samples (e.g., snake venom) the application of the simple and cheap bare fused silica capillary can be considered as an efficient choice.
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Affiliation(s)
- N Hamidli
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary
| | - M Andrasi
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary
| | - C Nagy
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary
| | - A Gaspar
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem ter 1, H-4032, Debrecen, Hungary.
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29
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Abstract
This paper describes Guided Search 6.0 (GS6), a revised model of visual search. When we encounter a scene, we can see something everywhere. However, we cannot recognize more than a few items at a time. Attention is used to select items so that their features can be "bound" into recognizable objects. Attention is "guided" so that items can be processed in an intelligent order. In GS6, this guidance comes from five sources of preattentive information: (1) top-down and (2) bottom-up feature guidance, (3) prior history (e.g., priming), (4) reward, and (5) scene syntax and semantics. These sources are combined into a spatial "priority map," a dynamic attentional landscape that evolves over the course of search. Selective attention is guided to the most active location in the priority map approximately 20 times per second. Guidance will not be uniform across the visual field. It will favor items near the point of fixation. Three types of functional visual field (FVFs) describe the nature of these foveal biases. There is a resolution FVF, an FVF governing exploratory eye movements, and an FVF governing covert deployments of attention. To be identified as targets or rejected as distractors, items must be compared to target templates held in memory. The binding and recognition of an attended object is modeled as a diffusion process taking > 150 ms/item. Since selection occurs more frequently than that, it follows that multiple items are undergoing recognition at the same time, though asynchronously, making GS6 a hybrid of serial and parallel processes. In GS6, if a target is not found, search terminates when an accumulating quitting signal reaches a threshold. Setting of that threshold is adaptive, allowing feedback about performance to shape subsequent searches. Simulation shows that the combination of asynchronous diffusion and a quitting signal can produce the basic patterns of response time and error data from a range of search experiments.
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Affiliation(s)
- Jeremy M Wolfe
- Ophthalmology and Radiology, Brigham & Women's Hospital/Harvard Medical School, Cambridge, MA, USA.
- Visual Attention Lab, 65 Landsdowne St, 4th Floor, Cambridge, MA, 02139, USA.
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30
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Brown A, Heckman RW. Light alters the impacts of nitrogen and foliar pathogens on the performance of early successional tree seedlings. PeerJ 2021; 9:e11587. [PMID: 34285829 PMCID: PMC8272923 DOI: 10.7717/peerj.11587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 05/20/2021] [Indexed: 11/24/2022] Open
Abstract
Light limitation is a major driver of succession and an important determinant of the performance of shade-intolerant tree seedlings. Shade intolerance may result from a resource allocation strategy characterized by rapid growth and high metabolic costs, which may make shade-intolerant species particularly sensitive to nutrient limitation and pathogen pressure. In this study, we evaluated the degree to which nitrogen availability and fungal pathogen pressure interact to influence plant performance across different light environments. To test this, we manipulated nitrogen availability (high, low) and access by foliar fungal pathogens (sprayed with fungicide, unsprayed) to seedlings of the shade-intolerant tree, Liquidambar styraciflua, growing at low and high light availability, from forest understory to adjacent old field. Foliar fungal damage varied with light and nitrogen availability; in low light, increasing nitrogen availability tripled foliar damage, suggesting that increased nutrient availability in low light makes plants more susceptible to disease. Despite higher foliar damage under low light, spraying fungicide to exclude pathogens promoted 14% greater plant height only under high light conditions. Thus, although nitrogen availability and pathogen pressure each influenced aspects of plant performance, these effects were context dependent and overwhelmed by light limitation. This suggests that failure of shade-intolerant species to invade closed-canopy forest can be explained by light limitation alone.
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Affiliation(s)
- Alexander Brown
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.,Curriculum for the Environment and Ecology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Robert W Heckman
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.,Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States of America
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31
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Quévreux P, Pigeault R, Loreau M. Predator avoidance and foraging for food shape synchrony and response to perturbations in trophic metacommunities. J Theor Biol 2021; 528:110836. [PMID: 34271013 DOI: 10.1016/j.jtbi.2021.110836] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 06/22/2021] [Accepted: 07/07/2021] [Indexed: 11/17/2022]
Abstract
The response of species to perturbations strongly depends on spatial aspects in populations connected by dispersal. Asynchronous fluctuations in biomass among populations lower the risk of simultaneous local extinctions and thus reduce the regional extinction risk. However, dispersal is often seen as passive diffusion that balances species abundance between distant patches, whereas ecological constraints, such as predator avoidance or foraging for food, trigger the movement of individuals. Here, we propose a model in which dispersal rates depend on the abundance of the species interacting with the dispersing species (e.g., prey or predators) to determine how density-dependent dispersal shapes spatial synchrony in trophic metacommunities in response to stochastic perturbations. Thus, unlike those with passive dispersal, this model with density-dependent dispersal bypasses the classic vertical transmission of perturbations due to trophic interactions and deeply alters synchrony patterns. We show that the species with the highest coefficient of variation of biomass governs the dispersal rate of the dispersing species and determines the synchrony of its populations. In addition, we show that this mechanism can be modulated by the relative impact of each species on the growth rate of the dispersing species. Species affected by several constraints disperse to mitigate the strongest constraints (e.g., predation), which does not necessarily experience the highest variations due to perturbations. Our approach can disentangle the joint effects of several factors implied in dispersal and provides a more accurate description of dispersal and its consequences on metacommunity dynamics.
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Affiliation(s)
- Pierre Quévreux
- Theoretical and Experimental Ecology Station, UPR 2001, CNRS, 09200 Moulis, France.
| | - Rémi Pigeault
- Theoretical and Experimental Ecology Station, UPR 2001, CNRS, 09200 Moulis, France
| | - Michel Loreau
- Theoretical and Experimental Ecology Station, UPR 2001, CNRS, 09200 Moulis, France
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32
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Cochrane BA, Wang C, Pratt J, Milliken B, Sun HJ. Comparing imagery and perception: Using eye movements to dissociate mechanisms in search. Atten Percept Psychophys 2021. [PMID: 34180031 DOI: 10.3758/s13414-021-02336-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2021] [Indexed: 11/08/2022]
Abstract
It has been demonstrated that color imagery can have a profound impact when generated prior to search, while at the same time, perceptual cues have a somewhat limited influence. Given this discrepancy, the present study evaluated the processes impacted by imagery and perception using a singleton search task where participants had to find an oddball colored target among homogenously colored distractors. Prior to each trial, a perceptual color was displayed or imagery was generated that could match the target, distractors, or neither item in the search array. It was revealed that color imagery led to both a larger benefit when it matched the target and a larger cost when it matched the distractors relative to perceptual cues. By parsing response times into pre-search, search, and response phases based on eye movements, it was revealed that, while imagery and perceptual cues both influenced the search phase, imagery had a significantly greater influence than perceptual cues. Further, imagery influenced pre-search and response phases as well. Overall, the present findings reveal that the influence of imagery is profound as it affects multiple processes in the vision-perception pipeline, while perception only appeared to impact search.
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Cochrane BA, Ng V, Milliken B. Top-down imagery overrides the influence of selection history effects. Conscious Cogn 2021; 93:103153. [PMID: 34049055 DOI: 10.1016/j.concog.2021.103153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 04/27/2021] [Accepted: 05/14/2021] [Indexed: 10/21/2022]
Abstract
The present study investigated whether color imagery could override the representations of the prevalent selection history effect termed Priming of Pop-out (PoP), which is constituted by faster responding when the target color is repeated rather than switched across trials of color singleton search. Participants imagined a color in the interval between trials of a color singleton search task that could be the same as or different to the previous target color, and they were to rate the vividness of these representations following each imagery event. It was revealed that when highly vivid imagery was reported, the PoP effect was attenuated relative to less vivid forms of it (and absent in two out of three experiments), and that color imagery eliminated the build-up of priming following consecutive target color repeats. Overall, the present findings suggest the representations of the selection history system can be overridden by top-down imagery.
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Affiliation(s)
- Brett A Cochrane
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Canada.
| | - Vanessa Ng
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Canada
| | - Bruce Milliken
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Canada
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Römer J, Stolz A, Kiessig S, Moritz B, Neusüß C. Online top-down mass spectrometric identification of CE(SDS)-separated antibody fragments by two-dimensional capillary electrophoresis. J Pharm Biomed Anal 2021; 201:114089. [PMID: 33940498 DOI: 10.1016/j.jpba.2021.114089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/01/2021] [Accepted: 04/19/2021] [Indexed: 12/26/2022]
Abstract
Size heterogeneity analysis by capillary sieving electrophoresis utilizing sodium dodecyl sulfate (CE(SDS)) with optical detection is a major method applied for release and stability testing of monoclonal antibodies (mAbs) in biopharmaceutical applications. Identification of mAb-fragments and impurities observed with CE(SDS) is of outstanding importance for the assessment of critical quality attributes and development of the analytical control system. Mass spectrometric (MS) detection is a powerful tool for protein identification and characterization. Unfortunately, CE(SDS) is incompatible with online MS-hyphenation due to strong ionization suppression of SDS and other separation buffer components. Here, we present a comprehensive platform for full characterization of individual CE(SDS)-separated peaks by CE(SDS)-capillary zone electrophoresis-top-down-MS. The peak of interest is transferred from the first to the second dimension via an 8-port valve to remove MS-incompatible components. Full characterization of mAb byproducts is performed by intact mass determination and fragmentation by electron transfer dissociation, higher-energy collisional dissociation, and ultraviolet photodissociation. This enables online determination of intact mass as well as sequence verification of individual CE(SDS)-separated peaks simultaneously. A more substantiated characterization of unknown CE(SDS) peaks by exact localization of modifications without prior digestion is facilitated. High sensitivity is demonstrated by successful mass and sequence verification of low abundant, unknown CE(SDS) peaks from two stressed mAb samples. Good fragmentation coverages are obtained by MS2, enabling unequivocal identification of these mAb-fragments. Also, the differentiation of reduced/non-reduced intra-protein disulfide bonds is demonstrated. In summary, a reliable and unambiguous online MS2 identification of unknown compounds of low-abundant individual CE(SDS) peaks is enabled.
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Affiliation(s)
- Jennifer Römer
- Faculty of Chemistry, Aalen University, Beethovenstraße 1, 73430, Aalen, Germany; Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, Regensburg, Germany
| | - Alexander Stolz
- Faculty of Chemistry, Aalen University, Beethovenstraße 1, 73430, Aalen, Germany; Department of Pharmaceutical/Medicinal Chemistry, Friedrich Schiller University, Jena, Germany
| | - Steffen Kiessig
- F. Hoffmann-La Roche Ltd, Grenzacherstraße 124, 4070, Basel, Switzerland
| | - Bernd Moritz
- F. Hoffmann-La Roche Ltd, Grenzacherstraße 124, 4070, Basel, Switzerland
| | - Christian Neusüß
- Faculty of Chemistry, Aalen University, Beethovenstraße 1, 73430, Aalen, Germany.
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35
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Nakamura H, Tawatsuji Y, Fang S, Matsui T. Explanation of emotion regulation mechanism of mindfulness using a brain function model. Neural Netw 2021; 138:198-214. [PMID: 33684653 DOI: 10.1016/j.neunet.2021.01.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 01/10/2021] [Accepted: 01/29/2021] [Indexed: 11/21/2022]
Abstract
The emotion regulation mechanism of mindfulness plays an important role in the stress reduction effect. Many researchers in the fields of cognitive psychology and cognitive neuroscience have attempted to elucidate this mechanism by documenting the cognitive processes that occur and the neural activities that characterize each process. However, previous findings have not revealed the mechanism of information propagation in the brain that achieves emotion regulation during mindfulness. In this study, we constructed a functional brain model based on its anatomical network structure and a computational model representing the propagation of information between brain regions. We then examined the effects of mindfulness meditation on information propagation in the brain using simulations of changes in the activity of each region. These simulations of changes represent the degree of processing resource allocation to the neural activity via changes in the weights of each region's output. As a result of the simulations, we reveal how the neural activity characteristic of emotion regulation in mindfulness, which has been reported in previous studies, is realized in the brain. Mindfulness meditation increases the weight of the output from each region of the thalamus and sensory cortex, which processes sensory stimuli from the external world. This sensory information activates the insula and anterior cingulate cortex (ACC). The orbitofrontal cortex and dorsolateral prefrontal cortex inhibit amygdala activity (i.e., top-down emotion regulation). However, when mindfulness meditation dominates bottom-up processing via sensory stimuli from the external world, amygdala activity increases through the insula and ACC activation.
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36
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Thompson C, Pasquini A, Hills PJ. Carry-over of attentional settings between distinct tasks: A transient effect independent of top-down contextual biases. Conscious Cogn 2021; 90:103104. [PMID: 33662677 DOI: 10.1016/j.concog.2021.103104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 02/12/2021] [Accepted: 02/12/2021] [Indexed: 10/22/2022]
Abstract
Top-down attentional settings can persist between two unrelated tasks, influencing visual attention and performance. This study investigated whether top-down contextual information in a second task could moderate this "attentional inertia" effect. Forty participants searched through letter strings arranged horizontally, vertically, or randomly and then made a judgement about road, nature, or fractal images. Eye movements were recorded to the picture search and findings showed greater horizontal search in the pictures following horizontal letter strings and narrower horizontal search following vertical letter strings, but only in the first 1000 ms. This shows a brief persistence of attentional settings, consistent with past findings. Crucially, attentional inertia did not vary according to image type. This indicates that top-down contextual biases within a scene have limited impact on the persistence of previously relevant, but now irrelevant, attentional settings.
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Affiliation(s)
| | - Alessia Pasquini
- School of Health and Society, University of Salford, Salford, UK
| | - Peter J Hills
- Department of Psychology, Bournemouth University, Poole, UK
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Alhassan RK, Nketiah-Amponsah E, Twum-Danso NAY, Bawa J, Kwarah W, Ucer S, Ibn Abass AF. " Top-down bottom-up" estimation of per capita cost of new-born care interventions in four regions of Ghana: beyond implementation to scalability and sustainability. Health Econ Rev 2021; 11:8. [PMID: 33635445 PMCID: PMC7913326 DOI: 10.1186/s13561-021-00307-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Limited financial, human and material health resources coupled with increasing demand for new-born care services require efficiency in health systems to maximize the available sources for improved health outcomes. Making Every Baby Count Initiative (MEBCI) implemented by local and international partners in 2013 in Ghana aimed at attaining neonatal mortality of 21 per 1000 livebirths by 2018 in four administrative regions in Ghana. MEBCI interventions benefited 4027 health providers, out of which 3453 (86%) were clinical healthcare staff. OBJECTIVE Determine the per capita cost of the MEBCI interventions towards enhancing new-born care best practices through capacity trainings for frontline clinical and non-clinical staff. METHODS Parameters for determining per capita cost of the new-born care interventions were estimated using expenditure on trainings, supervisions, monitoring and evaluation, advocacy, administrative/services and medical logistics. Data collection started in October 2017 and ended in September 2018. Data sources for the per capita cost estimations were invoices, expense reports and ledger books at the national, regional and district levels of the health system. RESULTS Total of 4027 healthcare providers benefited from the MEBCI training activities comprising of 3453 clinical staff and 574 non-clinical personnel. Cumulative cost of implementing the MEBCI interventions did not necessarily match the cost per capita in staff capacity building; average cost per capita for all staff (clinical and non-clinical staff) was approximately US$ 982 compared to a per capita cost of US$ 799 for training only core clinical staff. Average cost per capita for all regions was approximately US$ 965 for all staff compared to US$ 777 per capita cost for only clinical staff. Per capita cost of training was relatively lower in regions with more staff than regions with lower numbers, perhaps due to economies of scale. CONCLUSION The MEBCI intervention had a wide coverage in terms of training for frontline healthcare providers albeit the associated cost may be potentially unsustainable for Ghana's health system. Emerging digital training platforms could be leveraged to reduce per capita cost of training. Large-scale on-site batch-training approach could also be replaced with facility-based workshops using training of trainers (TOTs) approach to promote efficiency.
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Affiliation(s)
- Robert Kaba Alhassan
- Centre for Health Policy and Implementation Research, Institute of Health Research, University of Health and Allied Sciences, PMB 31, Ho, Volta Region Ghana
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Dowdle LT, Ghose G, Ugurbil K, Yacoub E, Vizioli L. Clarifying the role of higher-level cortices in resolving perceptual ambiguity using ultra high field fMRI. Neuroimage 2021; 227:117654. [PMID: 33333319 PMCID: PMC10614695 DOI: 10.1016/j.neuroimage.2020.117654] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/17/2020] [Accepted: 12/05/2020] [Indexed: 12/17/2022] Open
Abstract
The brain is organized into distinct, flexible networks. Within these networks, cognitive variables such as attention can modulate sensory representations in accordance with moment-to-moment behavioral requirements. These modulations can be studied by varying task demands; however, the tasks employed are often incongruent with the postulated functions of a sensory system, limiting the characterization of the system in relation to natural behaviors. Here we combine domain-specific task manipulations and ultra-high field fMRI to study the nature of top-down modulations. We exploited faces, a visual category underpinned by a complex cortical network, and instructed participants to perform either a stimulus-relevant/domain-specific or a stimulus-irrelevant task in the scanner. We found that 1. perceptual ambiguity (i.e. difficulty of achieving a stable percept) is encoded in top-down modulations from higher-level cortices; 2. the right inferior-temporal lobe is active under challenging conditions and uniquely encodes trial-by-trial variability in face perception.
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Affiliation(s)
- Logan T Dowdle
- Center for Magnetic Resonance Research, University of Minnesota 2021 6th St SE, Minneapolis, MN 55455, United States; Department of Neuroscience, University of Minnesota, 321 Church St SE, Minneapolis, MN 55455.
| | - Geoffrey Ghose
- Center for Magnetic Resonance Research, University of Minnesota 2021 6th St SE, Minneapolis, MN 55455, United States; Department of Neuroscience, University of Minnesota, 321 Church St SE, Minneapolis, MN 55455
| | - Kamil Ugurbil
- Center for Magnetic Resonance Research, University of Minnesota 2021 6th St SE, Minneapolis, MN 55455, United States
| | - Essa Yacoub
- Center for Magnetic Resonance Research, University of Minnesota 2021 6th St SE, Minneapolis, MN 55455, United States
| | - Luca Vizioli
- Center for Magnetic Resonance Research, University of Minnesota 2021 6th St SE, Minneapolis, MN 55455, United States; Department of Neurosurgery, University of Minnesota, 500 SE Harvard St, Minneapolis, MN 55455.
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Mahadas S, Semkewyc C, Suresh S, Hung GK. Scan path during change-detection visual search. Comput Biol Med 2021; 131:104233. [PMID: 33561672 DOI: 10.1016/j.compbiomed.2021.104233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/16/2021] [Accepted: 01/16/2021] [Indexed: 11/25/2022]
Abstract
When observing a particular image or object, one's perception depends upon prior expectations, memory, and cognitive abilities. It is hypothesized that cognitive processing in the form of top-down or bottom-up processing could be determined via analysis of the eye fixation scan path. To assess the variations in scan paths, 7 subjects underwent 5 change-detection trials. During each trial, they were presented with a specific set of images via a MATLAB program, in which the original image alternated with a modified image consisting of a single change. An open-source program called GazeRecorder was used to track the subject's eye movements and to record the eye fixations. The scan path was then analyzed through the use of a 4 by 4 grid pattern superimposed on the image to determine the subject's eye fixation distribution pattern in terms of Boxes Viewed and Concentration within a single area. It was determined that higher Concentration was positively correlated with faster Detection Speed (R = 0.84), while higher number of Boxes Viewed was negatively correlated with Detection Speed (R = -0.71). Among the subjects, the more optimal scan paths were found in those with a balance between Concentration and Boxes Viewed, as subjects with a more balanced approach had the greatest Accuracy (p = 0.02). This indicates an optimal scan path involves both top-down and bottom-up processing to more efficiently identify a change. Moreover, the methodology developed in this study could be used in the home or clinic for quantitative assessment of improvement following therapy in patients with neurological deficits.
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Affiliation(s)
- Srikrishnaraja Mahadas
- Department of Electrical and Computer Engineering, Rutgers University, Piscataway, NJ, USA
| | - Courtney Semkewyc
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, USA
| | - Shradha Suresh
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, USA
| | - George K Hung
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, USA.
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Zhang M, Varga D, Wang X, Krieger-Redwood K, Gouws A, Smallwood J, Jefferies E. Knowing what you need to know in advance: The neural processes underpinning flexible semantic retrieval of thematic and taxonomic relations. Neuroimage 2021; 224:117405. [PMID: 32992002 PMCID: PMC7779371 DOI: 10.1016/j.neuroimage.2020.117405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/22/2020] [Accepted: 09/22/2020] [Indexed: 11/26/2022] Open
Abstract
Semantic retrieval is flexible, allowing us to focus on subsets of features and associations that are relevant to the current task or context: for example, we use taxonomic relations to locate items in the supermarket (carrots are a vegetable), but thematic associations to decide which tools we need when cooking (carrot goes with peeler). We used fMRI to investigate the neural basis of this form of semantic flexibility; in particular, we asked how retrieval unfolds differently when participants have advanced knowledge of the type of link to retrieve between concepts (taxonomic or thematic). Participants performed a semantic relatedness judgement task: on half the trials, they were cued to search for a taxonomic or thematic link, while on the remaining trials, they judged relatedness without knowing which type of semantic relationship would be relevant. Left inferior frontal gyrus showed greater activation when participants knew the trial type in advance. An overlapping region showed a stronger response when the semantic relationship between the items was weaker, suggesting this structure supports both top-down and bottom-up forms of semantic control. Multivariate pattern analysis further revealed that the neural response in left inferior frontal gyrus reflects goal information related to different conceptual relationships. Top-down control specifically modulated the response in visual cortex: when the goal was unknown, there was greater deactivation to the first word, and greater activation to the second word. We conclude that top-down control of semantic retrieval is primarily achieved through the gating of task-relevant 'spoke' regions.
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Affiliation(s)
- Meichao Zhang
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD.
| | - Dominika Varga
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | - Xiuyi Wang
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | | | - Andre Gouws
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | - Jonathan Smallwood
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD
| | - Elizabeth Jefferies
- Department of Psychology, University of York, Heslington, York, UK, YO10 5DD.
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Yuan J, Zhang Q, Cui L. Disgust face captures more attention in individuals with high social anxiety when cognitive resources are abundant: Evidence from N2pc. Neuropsychologia 2020; 151:107731. [PMID: 33347915 DOI: 10.1016/j.neuropsychologia.2020.107731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/12/2020] [Accepted: 12/15/2020] [Indexed: 11/16/2022]
Abstract
There is a debate about the relative contributions of top-down and bottom-up attention to the threat-related attentional bias. In this study we investigated the attentional bias in individuals with social anxiety under conditions of no, low and high visual working memory (WM) load. Event-related potential (ERP) and response time (RT) data were recorded while participants performed the dot-probe task and a concurrent change-detection task. The ERP results revealed that the maximum N2pc effect emerged in no visual WM load condition in individuals with social anxiety. The difference of N2pc effect between high socially anxious (HSA) and low socially anxious (LSA) groups was observed in no visual WM load condition, whereas this difference was eliminated under low and high load conditions. However, no significant main effects or interactions were observed in the behavioral index (reflected by Trial Level-Bias Score variability). Overall, the findings indicate the critical role of top-down attention on social anxiety-related attentional bias, which have important implication for attentional bias modification.
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Affiliation(s)
- Jing Yuan
- Beijing Key Laboratory of Learning and Cognition and School of Psychology, Capital Normal University, Beijing, China; School of Teacher Education, Hebei Normal University for Nationalities, Chengde, China
| | - Qin Zhang
- Beijing Key Laboratory of Learning and Cognition and School of Psychology, Capital Normal University, Beijing, China
| | - Lixia Cui
- Beijing Key Laboratory of Learning and Cognition and School of Psychology, Capital Normal University, Beijing, China.
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Zhao C, Song X, Liu Y, Fu Y, Ye L, Wang N, Wang F, Li L, Mohammadniaei M, Zhang M, Zhang Q, Liu J. Synthesis of graphene quantum dots and their applications in drug delivery. J Nanobiotechnology 2020; 18:142. [PMID: 33008457 PMCID: PMC7532648 DOI: 10.1186/s12951-020-00698-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/24/2020] [Indexed: 12/23/2022] Open
Abstract
This review focuses on the recent advances in the synthesis of graphene quantum dots (GQDs) and their applications in drug delivery. To give a brief understanding about the preparation of GQDs, recent advances in methods of GQDs synthesis are first presented. Afterwards, various drug delivery-release modes of GQDs-based drug delivery systems such as EPR-pH delivery-release mode, ligand-pH delivery-release mode, EPR-Photothermal delivery-Release mode, and Core/Shell-photothermal/magnetic thermal delivery-release mode are reviewed. Finally, the current challenges and the prospective application of GQDs in drug delivery are discussed.
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Affiliation(s)
- Changhong Zhao
- School of Life Sciences and Technology, Xinxiang Medical University, Xinxiang, 453003, P. R. China.
- Electronics Materials and Systems Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
| | - Xuebin Song
- School of Life Sciences and Technology, Xinxiang Medical University, Xinxiang, 453003, P. R. China
| | - Ya Liu
- Electronics Materials and Systems Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Yifeng Fu
- Electronics Materials and Systems Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden
| | - Lilei Ye
- SHT Smart High-Tech AB, 411 33, Gothenburg, Sweden
| | - Nan Wang
- SHT Smart High-Tech AB, 411 33, Gothenburg, Sweden
| | - Fan Wang
- School of Life Sciences and Technology, Xinxiang Medical University, Xinxiang, 453003, P. R. China
| | - Lu Li
- School of Life Sciences and Technology, Xinxiang Medical University, Xinxiang, 453003, P. R. China
| | - Mohsen Mohammadniaei
- Department of Health Technology, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Ming Zhang
- Department of Health Technology, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Qiqing Zhang
- School of Life Sciences and Technology, Xinxiang Medical University, Xinxiang, 453003, P. R. China.
| | - Johan Liu
- Electronics Materials and Systems Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
- School of Automation and Mechanical Engineering, SMIT Center, Shanghai University, No 20, Chengzhong Road, Box 808, ShanghaiShanghai, 201800, China.
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Cleland TP, Schroeter ER, Colleary C. Diagenetiforms: A new term to explain protein changes as a result of diagenesis in paleoproteomics. J Proteomics 2020; 230:103992. [PMID: 32992016 DOI: 10.1016/j.jprot.2020.103992] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 09/11/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022]
Abstract
The term proteoform describes all combinations of change in a protein, as elucidated through intact mass proteomics. Paleoproteomic studies have begun using digestion-free and top-down techniques to access information from ancient and historical remains. However, to discuss protein changes that uniquely occur to archaeological and paleontological proteomes as the result of diagenesis (i.e., physical and chemical change imparted by burial), a novel term is needed that both addresses issues of combinatorics and distinguishes diagenetic-specific alteration. SIGNIFICANCE: The term diagenetiform provides the opportunity to communicate clearly the sets of diagenetic changes found on preserved proteins. The diagenetiform nomenclature will allow for top-down paleoproteomic studies to accurately describe the total changes detected on ancient proteins.
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Affiliation(s)
- Timothy P Cleland
- Museum Conservation Institute, Smithsonian Institution, Suitland, MD 20746, United States of America.
| | - Elena R Schroeter
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States of America
| | - Caitlin Colleary
- Department of Vertebrate Paleontology, Cleveland Museum of Natural History, Cleveland, OH 44106, United States of America
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Cassidy L, Helbig AO, Kaulich PT, Weidenbach K, Schmitz RA, Tholey A. Multidimensional separation schemes enhance the identification and molecular characterization of low molecular weight proteomes and short open reading frame-encoded peptides in top-down proteomics. J Proteomics 2020; 230:103988. [PMID: 32949814 DOI: 10.1016/j.jprot.2020.103988] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/17/2020] [Accepted: 09/14/2020] [Indexed: 12/13/2022]
Abstract
Short open reading frame-encoded peptides (SEP) represent a widely undiscovered part of the proteome. The detailed analysis of SEP has, despite inherent limitations such as incomplete sequence coverage, challenges encountered with protein inference, the identification of posttranslational modifications and the assignment of potential N- and C-terminal truncations, predominantly been assessed using bottom-up proteomic workflows. The use of top-down based proteomic workflows is capable of providing an unparalleled level of characterization information, which is of increased importance in the case of alternatively encoded protein products. However, top-down based analysis is not without its own limitations, for which efficient separation prior to MS analysis is a major issue. We established a sample preparation approach for the combined bottom-up and top-down proteomic analysis of SEP. Key improvements were made by the application of solid phase extraction (SPE), which supported enrichment of proteins below ca. 20 kDa, followed by 2D-LC-MS top-down analysis encompassing both HCD and EThcD ion activation. Bottom-up experiments were used to support and confirm top-down data interpretation. This strategy allowed for the top-down characterization of 36 proteoforms mapping to 12 SEP from the archaeon Methanosarcina mazei strain Gö1, with the concurrent detection and identification of several posttranslational modifications in SEP. BIOLOGICAL SIGNIFICANCE: Small or short open reading frames (sORF) have been widely neglected in genome research in the past. With their increasing discovery, the question about the presence and molecular function of their translation products, the short open reading frame-encoded peptides (SEP), arises. As these small proteins are usually below the 10 kDa range, the number of peptides identifiable by bottom-up proteomics is limited which hampers both the identification and the recognition of potential posttranslational modifications. The presented top-down approach allowed for the detection of full length SEP, as well as of terminally truncated proteoforms, and further enabled the identification of disulfide bonds in these small proteins. This demonstrates, that this yet widely undiscovered part of the proteome undergoes the same modifications as classical proteins which is an essential step for future understanding of the biological functions of these molecules.
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Affiliation(s)
- Liam Cassidy
- Systematic Proteome Research & Bioanalytics, Institute for Experimental Medicine, Christian-Albrechts-Universität zu Kiel, 24105 Kiel, Germany
| | - Andreas O Helbig
- Systematic Proteome Research & Bioanalytics, Institute for Experimental Medicine, Christian-Albrechts-Universität zu Kiel, 24105 Kiel, Germany
| | - Philipp T Kaulich
- Systematic Proteome Research & Bioanalytics, Institute for Experimental Medicine, Christian-Albrechts-Universität zu Kiel, 24105 Kiel, Germany
| | - Kathrin Weidenbach
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany
| | - Ruth A Schmitz
- Institute for General Microbiology, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany
| | - Andreas Tholey
- Systematic Proteome Research & Bioanalytics, Institute for Experimental Medicine, Christian-Albrechts-Universität zu Kiel, 24105 Kiel, Germany.
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Thomas KN, Bardeen JR. The buffering effect of attentional control on the relationship between cognitive fusion and anxiety. Behav Res Ther 2020; 132:103653. [PMID: 32544636 DOI: 10.1016/j.brat.2020.103653] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 05/19/2020] [Accepted: 05/25/2020] [Indexed: 12/30/2022]
Abstract
Cognitive fusion has been identified as a risk factor for anxiety. Evidence suggests that those with better attentional control may be able to flexibly shift attention from an internal to external focus, thus reducing contact with negative self-referent thoughts. As such, attentional control was examined as a moderator of the relation between cognitive fusion and anxiety in this two-part study. Adult participants (N = 597) completed self-report measures in Study 1. In Study 2, adult student participants (N = 173) completed self-report measures of cognitive fusion and anxiety, as well as behavioral measures that assessed three specific attentional control processes (i.e., inhibition, shifting, working memory updating). As predicted, attentional control moderated the relation between cognitive fusion and anxiety such that the strength of the relation decreased as attentional control increased. The results of Study 2 suggest that inhibitory ability is the attentional control process that accounts for this effect. Taken together, results suggest the possibility that attentional control (especially inhibitory ability) may be a protective factor against the development of anxiety among those with higher levels of cognitive fusion. The use of experimental and longitudinal study designs will be an important next step in this line of research to further clarify the nature of relations among cognitive fusion, attentional control, and anxiety. Results from an exploratory analysis, in which depressive symptoms served as the outcome variable, will also be discussed.
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Zhou AB, Sang HB, Wang AJ, Zhang M. Visual aperiodic temporal prediction increases perceptual sensitivity and reduces response latencies. Acta Psychol (Amst) 2020; 209:103129. [PMID: 32619784 DOI: 10.1016/j.actpsy.2020.103129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 06/17/2020] [Accepted: 06/22/2020] [Indexed: 11/23/2022] Open
Abstract
As a predictive organ, the brain can predict upcoming events to guide perception and action in the process of adaptive behavior. The classical models of oscillatory entrainment explain the facilitating effects that occur after periodic stimulation in behavior but cannot explain aperiodic facilitating effects. In the present study, by comparing the behavior performance of participants in periodic predictable (PP), aperiodic predictable (AP) and aperiodic unpredictable (AU) stimulus streams, we investigated the effect of an aperiodic predictable stream on the perceptual sensitivity and response latencies in the visual modality. The results showed that there was no difference between PP and AP conditions in sensitivity (d') and reaction times (RTs), both of which were significantly different from those in the AU condition. Moreover, a significant correlation between d' and RTs was observed when predictability existed. These results indicate that the aperiodic predictable stimulus streams increases perceptual sensitivity and reduces response latencies in a top-down manner. Individuals proactively and flexibly predict upcoming events based on the temporal structure of visual stimuli in the service of adaptive behavior.
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Dunne L, Opitz B. Attention control processes that prioritise task execution may come at the expense of incidental memory encoding. Brain Cogn 2020; 144:105602. [PMID: 32771684 DOI: 10.1016/j.bandc.2020.105602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/14/2020] [Accepted: 07/17/2020] [Indexed: 01/12/2023]
Abstract
Attention underpins episodic memory encoding by gating information processing. However, it is unclear how different forms of attention affect encoding. Using fMRI, we implemented a novel task that separates top-down and bottom-up attention (TDA; BUA) to test how these forms of attention influence encoding. Twenty-seven subjects carried out a scanned incidental encoding task that required semantic categorisation of stimuli. Trials either required visual search (TDA) to locate a target, or the target blinked and captured attention (BUA). After a retention period, subjects performed a surprise recognition test. Univariate analyses showed that ventral visual regions and right hippocampus indexed encoding success. Psychophysiological interaction analyses showed that, during TDA, there was increased coupling between dorsal parietal cortex and fusiform gyrus with encoding failure, and between lateral occipital cortex and fusiform gyrus with encoding success. No significant connectivity modulations were observed during BUA. We propose that increased TDA to objects in space is mediated by parietal cortex and negatively impacts encoding. Also, increases in connectivity within ventral visual cortex index the integration of stimulus features, promoting encoding. Finally, the influences of attention on encoding likely depend on task demands: as cognitive control increases, task execution is emphasised at the expense of memory encoding.
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Affiliation(s)
- Lewis Dunne
- University of Surrey, GU2 7XH, United Kingdom.
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Wang CA, Huang J, Brien DC, Munoz DP. Saliency and priority modulation in a pop-out paradigm: Pupil size and microsaccades. Biol Psychol 2020; 153:107901. [PMID: 32389837 DOI: 10.1016/j.biopsycho.2020.107901] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/16/2020] [Accepted: 04/27/2020] [Indexed: 11/16/2022]
Abstract
A salient stimulus can trigger a coordinated orienting response consisting of a saccade, pupil, and microsaccadic responses. Saliency models predict that the degree of visual conspicuity of all visual stimuli guides visual orienting. By presenting a multiple-item array that included an oddball colored item (pop-out), randomly mixed colored items (mixed-color), or single-color items (single-color), we examined the effects of saliency and priority (saliency + relevancy) on pupil size and microsaccade responses. Larger pupil responses were produced in the pop-out compared to the mixed-color or single-color conditions after stimulus presentation. However, the saliency modulation on microsaccades was not significant. Furthermore, although goal-relevancy information did not modulate pupil responses and microsaccade rate, microsaccade direction was biased toward the pop-out item when it was the subsequent saccadic target. Together, our results demonstrate saliency modulation on pupil size and priority effects on microsaccade direction during visual pop-out.
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Affiliation(s)
- Chin-An Wang
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada; Research Center of Brain and Consciousness, Department of Anesthesiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; Graduate Institute of Mind, Brain, and Consciousness, Taipei Medical University, Taipei, Taiwan.
| | - Jeff Huang
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Donald C Brien
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Douglas P Munoz
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada.
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Russell CG, Russell A. "Food" and "non-food" self-regulation in childhood: a review and reciprocal analysis. Int J Behav Nutr Phys Act 2020; 17:33. [PMID: 32151265 PMCID: PMC7063723 DOI: 10.1186/s12966-020-00928-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/10/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND In developmental science, there is an extensive literature on non-food related self-regulation in childhood, where several domains relating to emotions, actions and cognitions have been identified. There is now growing attention to food related self-regulation in childhood, especially difficulties with ASR, and the consequences for weight gain and adiposity. The aim of this narrative review was to conduct a reciprocal analysis of self-regulation in the food and non-food domains in childhood (referred to as appetite self-regulation (ASR) and general self-regulation (GSR) respectively). The focus was on commonalities and differences in key concepts and underpinning processes. METHODS Databases and major journals were searched using terms such as self-regulation, appetite self-regulation, or self-regulation of energy intake, together with associated constructs (e.g., Executive Function, Effortful Control, delay-of-gratification). This was followed by backward and forward snowballing. RESULTS AND DISCUSSION The scholarship on GSR in childhood has had a focus on the role of the cognitively-oriented Executive Function (EF), the temperamentally-based Effortful Control (EC) and the recursive interplay between bottom-up (reactive, emotion driven, approach or avoidance) and top-down (cognitive, conscious decision-making) processes. "Hot" and "cool/cold" EF and self-regulation situations have been distinguished. There were some parallels between GSR and ASR in these areas, but uncertainty about the contribution of EF and EC to ASR in young children. Possible differences between the contribution to ASR-related outcomes of delay-of-gratification in food and non-food tasks were apparent. Unique elements of ASR were identified; associated with psychological, biological and neurological responses to food and bottom-up processes. A diverse number of situations or elements connected to ASR exist: for example, energy balance homeostasis, caloric compensation, hunger regulation, satiation, satiety, energy density of food, eating in the absence of hunger, emotional eating, etc. CONCLUSIONS: Self-regulation in food and non-food domains are amenable to a reciprocal analysis. We argue that self-regulation of appetite should be added as a domain under the umbrella of self-regulation in childhood along with the other non-food related domains. This could lead to a broader understanding of self-regulation in childhood, and generate novel lines of enquiry.
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Affiliation(s)
- Catherine G Russell
- Faculty of Health, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia.
| | - Alan Russell
- College of Education, Psychology and Social Work, Flinders University, Sturt Rd, Bedford Park, South Australia, 5042, Australia
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Abstract
Exosomes have emerged as appealing candidate therapeutic agents and delivery nanoplatforms due to their endogenous features and unique biological properties. However, obstacles such as low isolation yield, considerable complexity and potential safety concerns, and inefficient drug payload substantially hamper their therapeutic applicability. To this end, developing bioinspired exosome-like nanoparticles has become a promising area to overcome certain limitations of their natural counterparts. Synthetically fabrication of exosome-like nanoparticles that harbor only crucial components of exosomes through controllable protocols strongly increases the pharmaceutical acceptability of these vesicles. Assembly of exosome-like nanovesicles derived from producer cells allows for a promising strategy for scale-up production. To improve the loading capability and delivery efficiency of exosomes, hybrid exosome-like nanovesicles and membrane-camouflaged nanoparticles towards better bridging synthetic nanocarriers with natural exosomes could be designed. Building off these observations, herein, efforts are made to give an overview of bioinspired exosome-like therapeutics and delivery nanoplatforms. We briefly recapitulate the recent advance in exosome biology with focus on tailoring exosomes as therapeutics and delivery vehicles. Furthermore, we elaborately discuss the biomimicry methodologies for preparation of exosome-like nanoparticles with special emphasis on offering insights into strategies for rational design of exosome-like biomaterials as effective and safe therapeutics and delivery nanoplatforms.
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Affiliation(s)
- Mei Lu
- School of Life Science, Advanced Research Institute of Multidisciplinary Science, Institute of Engineering Medicine, Key Laboratory of Molecular Medicine and Biotherapy, Beijing Institute of Technology, Beijing, 100081, PR China
| | - Yuanyu Huang
- School of Life Science, Advanced Research Institute of Multidisciplinary Science, Institute of Engineering Medicine, Key Laboratory of Molecular Medicine and Biotherapy, Beijing Institute of Technology, Beijing, 100081, PR China.
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