126
|
Rey-Campos M, Moreira R, Romero A, Medina-Gali RM, Novoa B, Gasset M, Figueras A. Transcriptomic Analysis Reveals the Wound Healing Activity of Mussel Myticin C. Biomolecules 2020; 10:biom10010133. [PMID: 31947557 PMCID: PMC7023338 DOI: 10.3390/biom10010133] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 12/13/2022] Open
Abstract
Myticin C is the most studied antimicrobial peptide in the marine mussel Mytilus galloprovincialis. Although it is constitutively expressed in mussel hemocytes and displays antibacterial, antiviral, and chemotactic functions, recent work has suggested that this molecule is mainly activated after tissue injury. Therefore, the main objective of this work was to characterize the hemocytes’ transcriptomic response after a myticin C treatment, in order to understand the molecular changes induced by this cytokine-like molecule. The transcriptome analysis revealed the modulation of genes related to cellular movement, such as myosin, transgelin, and calponin-like proteins, in agreement with results of functional assays, where an implication of myticin C in the in vitro activation of hemocytes and migration was evidenced. This was also observed in vivo after a tissue injury, when hemocytes, with high concentrations of myticin C, migrated to the damaged area to heal the wound. All these properties allowed us to think about the biotechnological application of these molecules as wound healers. Human keratinocytes and larvae zebrafish models were used to confirm this hypothesis. Accelerated regeneration after a wound or tail fin amputation was observed after treatment with the myticin C peptide, supporting the chemotactic and healing activity of myticin C.
Collapse
|
127
|
Collin DE, Folgueiras‐Amador AA, Pletcher D, Light ME, Linclau B, Brown RCD. Cubane Electrochemistry: Direct Conversion of Cubane Carboxylic Acids to Alkoxy Cubanes Using the Hofer-Moest Reaction under Flow Conditions. Chemistry 2020; 26:374-378. [PMID: 31593312 PMCID: PMC6973092 DOI: 10.1002/chem.201904479] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Indexed: 12/12/2022]
Abstract
The highly strained cubane system is of great interest as a scaffold and rigid linker in both pharmaceutical and materials chemistry. The first electrochemical functionalisation of cubane by oxidative decarboxylative ether formation (Hofer-Moest reaction) was demonstrated. The mild conditions are compatible with the presence of other oxidisable functional groups, and the use of flow electrochemical conditions allows straightforward upscaling.
Collapse
|
128
|
Carretero LM, Latorre JM, Fernández D, Barry TJ, Ricarte JJ. Effects of positive personal and non-personal autobiographical stimuli on emotional regulation in older adults. Aging Clin Exp Res 2020; 32:157-164. [PMID: 30805866 PMCID: PMC6974493 DOI: 10.1007/s40520-019-01147-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 02/09/2019] [Indexed: 11/29/2022]
Abstract
People can regulate negative emotional states using personal episodic information stored in memory. However, amongst older adults, assistance in retrieving personal memories might be needed. As such, positive personal images might better facilitate the retrieval of positive personal memories, relative to generic positive images. The present study induced older adults (N = 40; Mage = 76.28) into a negative mood state using a validated film clip ("Dead Man Walking"; Robbins et al. in Dead Man Walking [Cinta Cinematográfica]. PolyGram Filmed Entertainment, Working Title Films, Estados Unidos, 1995). Participants were then shown positive personal images (album photos) or positive non-personal images from the International Affective Picture System (IAPS) and between-group differences in their mood state and their ability to retrieve positive autobiographical memories were measured. Although participants' moods decreased after the negative mood induction, their mood then recovered after picture cuing regardless of whether images were personal or non-personal. Furthermore, the positive mood evoked by non-personal, but not personal, images was significantly positively associated with self-reported feelings of reliving of the memories evoked by those images. These results suggest that, when pictures from personal life are not available, the selection of images able to generate positive autobiographical memories with a sense of reliving, is a feasible tool for older adult's emotional regulation.
Collapse
|
129
|
Krska D, Larsbrink J. Investigation of a thermostable multi-domain xylanase-glucuronoyl esterase enzyme from Caldicellulosiruptor kristjanssonii incorporating multiple carbohydrate-binding modules. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:68. [PMID: 32308737 PMCID: PMC7151638 DOI: 10.1186/s13068-020-01709-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/02/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Efficient degradation of lignocellulosic biomass has become a major bottleneck in industrial processes which attempt to use biomass as a carbon source for the production of biofuels and materials. To make the most effective use of the source material, both the hemicellulosic as well as cellulosic parts of the biomass should be targeted, and as such both hemicellulases and cellulases are important enzymes in biorefinery processes. Using thermostable versions of these enzymes can also prove beneficial in biomass degradation, as they can be expected to act faster than mesophilic enzymes and the process can also be improved by lower viscosities at higher temperatures, as well as prevent the introduction of microbial contamination. RESULTS This study presents the investigation of the thermostable, dual-function xylanase-glucuronoyl esterase enzyme CkXyn10C-GE15A from the hyperthermophilic bacterium Caldicellulosiruptor kristjanssonii. Biochemical characterization of the enzyme was performed, including assays for establishing the melting points for the different protein domains, activity assays for the two catalytic domains, as well as binding assays for the multiple carbohydrate-binding domains present in CkXyn10C-GE15A. Although the enzyme domains are naturally linked together, when added separately to biomass, the expected boosting of the xylanase action was not seen. This lack of intramolecular synergy might suggest, together with previous data, that increased xylose release is not the main beneficial trait given by glucuronoyl esterases. CONCLUSIONS Due to its thermostability, CkXyn10C-GE15A is a promising candidate for industrial processes, with both catalytic domains exhibiting melting temperatures over 70 °C. Of particular interest is the glucuronoyl esterase domain, as it represents the first studied thermostable enzyme displaying this activity.
Collapse
|
130
|
Tondi G, Cefarin N, Sepperer T, D’Amico F, Berger RJF, Musso M, Birarda G, Reyer A, Schnabel T, Vaccari L. Understanding the Polymerization of Polyfurfuryl Alcohol: Ring Opening and Diels-Alder Reactions. Polymers (Basel) 2019; 11:E2126. [PMID: 31861244 PMCID: PMC6969920 DOI: 10.3390/polym11122126] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/09/2019] [Accepted: 12/09/2019] [Indexed: 11/23/2022] Open
Abstract
Polyfurfuryl alcohol (PFA) is one of the most intriguing polymers because, despite its easy polymerization in acid environment, its molecular structure is definitely not obvious. Many studies have been performed in recent decades, and every time, surprising aspects came out. With the present study, we aim to take advantage of all of the findings of previous investigations and exploit them for the interpretation of the completely cured PFA spectra registered with three of the most powerful techniques for the characterization of solid, insoluble polymers: Solid-State 13C-NMR, Attenuated Total Reflectance (ATR), Fourier Transform Infrared (FTIR) spectroscopy, and UV-resonant Raman spectroscopy at different excitation wavelengths, using both an UV laser source and UV synchrotron radiation. In addition, the foreseen structures were modeled and the corresponding 13C-NMR and FTIR spectra were simulated with first-principles and semi-empiric methods to evaluate their matching with experimental ones. Thanks to this multi-technique approach, based on complementary analytical tools and computational support, it was possible to conclude that, in addition to the major linear unconjugated polymerization, the PFA structure consists of Diels-Alder rearrangements occurring after the opening of some furanic units, while the terminal moieties of the chain involves γ-lactone arrangements. The occurrence of head-head methylene ether bridges and free hydroxyl groups (from unreacted furfuryl alcohol, FA, or terminal chains) could be excluded, while the conjugated systems could be considered rather limited.
Collapse
|
131
|
Olsen PØ, Termannsen AD, Bramming M, Tully MA, Caserotti P. Effects of resistance training on self-reported disability in older adults with functional limitations or disability - a systematic review and meta-analysis. Eur Rev Aging Phys Act 2019; 16:24. [PMID: 31867068 PMCID: PMC6898935 DOI: 10.1186/s11556-019-0230-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/08/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Self-reported disability has a strong negative impact on older people's quality of life and is often associated with the need for assistance and health care services. Resistance training (RT) has been repeatedly shown to improve muscle function (e.g. strength) and functional capacity (e.g. gait speed, chair-rise) in older adults with functional limitations. Nevertheless, it is unclear whether such objectively assessed improvements translate into a reduction in self-reported disability. OBJECTIVES To assess: i) whether and to what extent RT interventions have an effect on self-reported disability in older adults (≥65 years) with functional limitations or disability; and ii) whether the effects on self-reported disability are associated with changes in objective measures of muscle strength and functional capacity across studies. METHODS PubMed, Embase, Web of Science, CINAHL and SPORTDiscus electronic databases were searched in June 2018. Randomized controlled trials reporting effects of RT on self-reported disability/function in ≥65 year-old adults with defined, functional limitations or self-reported disability were eligible. Data on self-reported disability/function were pooled by calculating adjusted standardized mean differences (SMD) using Hedges'g. Likewise, effect sizes for three secondary outcomes: knee extensor muscle strength; gait capacity; and lower body functional capacity were calculated and fit as covariates in separate meta-regressions with self-reported disability as the dependent factor. RESULTS Fourteen RCTs were eligible for the primary meta-analysis on self-reported disability. The total number of participants was 651 (intervention n = 354; control n = 297). A significant moderate positive effect of RT was found (SMD: 0.59, 95% CI: 0.253 to 0.925, p = 0.001). Between-study heterogeneity was present (I2 statistic = 75,1%, p < 0.001). RT effects on objective measures of lower body functional capacity were significantly associated with effects on self-reported disability (Adj. R2 = 99%, p = 0.002, n = 12 studies), whereas no significant associations with gait capacity or knee extensor strength were found. CONCLUSIONS This review provides evidence that RT has a moderate positive effect on self-reported disability/function in old people with or at risk for disability. The effects are strongly associated with effects on objective measures of lower body functional capacity.
Collapse
|
132
|
Rades D, Hansen O, Jensen LH, Dziggel L, Staackmann C, Doemer C, Cacicedo J, Conde-Moreno AJ, Segedin B, Ciervide-Jurio R, Rubio-Rodriguez C, Perez-Romasanta LA, Alvarez-Gracia A, Dennis K, Ferrer-Albiach C, Navarro-Martin A, Lopez-Campos F, Jankarashvili N, Janssen S, Olbrich D, Holländer NH. Radiotherapy for metastatic spinal cord compression with increased radiation doses (RAMSES-01): a prospective multicenter study. BMC Cancer 2019; 19:1163. [PMID: 31783816 PMCID: PMC6884857 DOI: 10.1186/s12885-019-6390-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 11/21/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Patients with metastatic spinal cord compression (MSCC) and favorable survival prognoses can benefit from radiation doses greater than 30Gy in 10 fractions in terms of improved local progression-free survival (LPFS) and overall survival (OS). METHODS/DESIGN This prospective study mainly investigates LPFS after precision radiotherapy (volumetric modulated arc therapy or stereotactic body radiotherapy) with 18 × 2.33Gy in 3.5 weeks. LPFS is defined as freedom from progression of motor deficits during radiotherapy and an in-field recurrence of MSCC following radiotherapy. The maximum relative dose allowed to the spinal cord is 101.5% of the prescribed dose, resulting in an equivalent dose in 2Gy-fractions (EQD2) for radiation myelopathy is 45.5Gy, which is below the tolerance dose of 50Gy according to the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC). The EQD2 of this regimen for tumor cell kill is 43.1Gy, which is 33% higher than for 30Gy in 10 fractions (EQD2 = 32.5Gy). Primary endpoint is LPFS at 12 months after radiotherapy. Secondary endpoints include the effect of 18 × 2.33Gy on motor function, ambulatory status, sensory function, sphincter dysfunction, LPFS at other follow-up times, overall survival, pain relief, relief of distress and toxicity. Follow-up visits for all endpoints will be performed directly and at 1, 3, 6, 9 and 12 months after radiotherapy. A total of 65 patients are required for the prospective part of the study. These patients will be compared to a historical control group of at least 235 patients receiving conventional radiotherapy with 10x3Gy in 2 weeks. DISCUSSION If precision radiotherapy with 18 × 2.33Gy results in significantly better LPFS than 10x3Gy of conventional radiotherapy, this regimen should be strongly considered for patients with MSCC and favorable survival prognoses. TRIAL REGISTRATION Clinicaltrials.gov NCT04043156. Registered 30-07-2019.
Collapse
|
133
|
Faict S, Oudaert I, D’Auria L, Dehairs J, Maes K, Vlummens P, De Veirman K, De Bruyne E, Fostier K, Vande Broek I, Schots R, Vanderkerken K, Swinnen JV, Menu E. The Transfer of Sphingomyelinase Contributes to Drug Resistance in Multiple Myeloma. Cancers (Basel) 2019; 11:cancers11121823. [PMID: 31756922 PMCID: PMC6966559 DOI: 10.3390/cancers11121823] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 02/07/2023] Open
Abstract
Multiple myeloma (MM) is well-known for the development of drug resistance, leading to relapse. Therefore, finding novel treatment strategies remains necessary. By performing a lipidomics assay on MM patient plasma, we aimed to identify new targets. We observed a dysregulation in the sphingolipid metabolism, with the upregulation of several ceramides and downregulation of sphingomyelin. This imbalance suggests an increase in sphingomyelinase, the enzyme responsible for hydrolyzing sphingomyelin into ceramide. We confirmed the upregulation of acid sphingomyelinase (ASM) in primary MM cells. Furthermore, we observed an increase in ASM expression in MM cell lines treated with melphalan or bortezomib, as well as in their exosomes. Exosomes high in ASM content were able to transfer the drug-resistant phenotype to chemosensitive cells, hereby suggesting a tumor-protective role for ASM. Finally, inhibition of ASM by amitriptyline improved drug sensitivity in MM cell lines and primary MM cells. In summary, this study is the first to analyze differences in plasma lipid composition of MM patients and match the observed differences to an upregulation of ASM. Moreover, we demonstrate that amitriptyline is able to inhibit ASM and increase sensitivity to anti-myeloma drugs. This study, therefore, provides a rational to include ASM-targeting-drugs in combination strategies in myeloma patients.
Collapse
|
134
|
Shi D, Nguyen DV, Maaloum M, Gallani JL, Felder-Flesch D, Krafft MP. Interfacial Behavior of Oligo(Ethylene Glycol) Dendrons Spread Alone and in Combination with a Phospholipid as Langmuir Monolayers at the Air/Water Interface. Molecules 2019; 24:E4114. [PMID: 31739495 PMCID: PMC6891365 DOI: 10.3390/molecules24224114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/09/2019] [Accepted: 11/11/2019] [Indexed: 01/11/2023] Open
Abstract
Dendrons consisting of two phosphonate functions and three oligo(ethylene glycol) (OEG) chains grafted on a central phenoxyethylcarbamoylphenoxy group were synthesized and investigated as Langmuir monolayers at the surface of water. The OEG chain in the para position was grafted with a t-Bu end-group, a hydrocarbon chain, or a partially fluorinated chain. These dendrons are models of structurally related OEG dendrons that were found to significantly improve the stability of aqueous dispersions of iron oxide nanoparticles when grafted on their surface. Compression isotherms showed that all OEG dendrons formed liquid-expanded Langmuir monolayers at large molecular areas. Further compression led to a transition ascribed to the solubilization of the OEG chains in the aqueous phase. Brewster angle microscopy (BAM) provided evidence that the dendrons fitted with hydrocarbon chains formed liquid-expanded monolayers throughout compression, whilst those fitted with fluorinated end-groups formed crystalline-like domains, even at large molecular areas. Dimyristoylphosphatidylcholine and dendron molecules were partially miscible in monolayers. The deviations to ideality were larger for the dendrons fitted with a fluorocarbon end-group chain than for those fitted with a hydrocarbon chain. Brewster angle microscopy and atomic force microscopy supported the view that the dendrons were ejected from the phospholipid monolayer during the OEG conformational transition and formed crystalline domains on the surface of the monolayer.
Collapse
|
135
|
Tamburello L, Papa L, Guarnieri G, Basconi L, Zampardi S, Scipione MB, Terlizzi A, Zupo V, Fraschetti S. Are we ready for scaling up restoration actions? An insight from Mediterranean macroalgal canopies. PLoS One 2019; 14:e0224477. [PMID: 31652294 PMCID: PMC6814225 DOI: 10.1371/journal.pone.0224477] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 10/15/2019] [Indexed: 11/23/2022] Open
Abstract
Extensive loss of macroalgal forests advocates for large-scale restoration interventions, to compensate habitat degradation and recover the associated ecological functions and services. Yet, restoration attempts have generally been limited to small spatial extensions, with the principal aim of developing efficient restoration techniques. Here, the success of outplanting Cystoseira amentacea v. stricta germlings cultured in aquaria was experimentally explored at a scale of tens of kms, by means of a multifactorial experimental design. In the intertidal rocky shores of SE Italy, locations with a continuous distribution for hundreds of meters or with few thalli forming patches of few centimeters of C. amentacea canopy were selected. In each location, the effects of adult conspecifics and the exclusion of macrograzers (salema fish and sea urchins) on the survival of germlings were tested. We evaluated the most critical determinants of mortality for germlings, including the overlooked pressure of mesograzers (e.g. amphipods, small mollusks, polychaetes). Despite the high mortality observed during outplanting and early settlement stages, survival of C. amentacea germlings was consistently favored by the exclusion of macrograzers, while the presence of adult conspecifics had no effects. In addition, the cost analysis of the interventions showed the feasibility of the ex-situ method, representing an essential tool for preserving Cystoseira forests. Large scale restoration is possible but requires baseline information with an in-depth knowledge of the species ecology and of the areas to be restored, together with the development of specific cultivation protocols to make consistently efficient restoration interventions.
Collapse
|
136
|
Segovia-Verjel ML, Requena-García-Cruz MV, de-Justo-Moscardó E, Morales-Esteban A. Optimal seismic retrofitting techniques for URM school buildings located in the southwestern Iberian peninsula. PLoS One 2019; 14:e0223491. [PMID: 31618221 PMCID: PMC6795483 DOI: 10.1371/journal.pone.0223491] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 09/22/2019] [Indexed: 11/20/2022] Open
Abstract
This paper aims to study different seismic retrofitting techniques to test the reduction of the seismic vulnerability of unreinforced masonry buildings. Three techniques have been considered in a case study: adding steel or carbon fibre reinforced polymer grids in the walls and steel encirclements in the openings. The performance-based method has been used to that purpose. Nonlinear static analyses have been performed to obtain the capacity and fragility curves, the performance point and the damage level states. Moreover, an analysis of the cost-benefit ratio has been carried out. Results have shown that the three techniques have produced considerable improvements. The addition of encirclements has reduced the deformation resulting in a slight increase of the structure’s stiffness. Adding steel grids has produced the maximum peak strength increase while adding polymer grids has produced the largest ultimate displacements. Adding encirclement has had the best cost-benefit ratio.
Collapse
|
137
|
Pereira H, Silva J, Santos T, Gangadhar KN, Raposo A, Nunes C, Coimbra MA, Gouveia L, Barreira L, Varela J. Nutritional Potential and Toxicological Evaluation of Tetraselmis sp. CTP4 Microalgal Biomass Produced in Industrial Photobioreactors. Molecules 2019; 24:E3192. [PMID: 31484299 PMCID: PMC6749414 DOI: 10.3390/molecules24173192] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/22/2019] [Accepted: 08/27/2019] [Indexed: 12/26/2022] Open
Abstract
Commercial production of microalgal biomass for food and feed is a recent worldwide trend. Although it is common to publish nutritional data for microalgae grown at the lab-scale, data about industrial strains cultivated in an industrial setting are scarce in the literature. Thus, here we present the nutritional composition and a microbiological and toxicological evaluation of Tetraselmis sp. CTP4 biomass, cultivated in 100-m3 photobioreactors at an industrial production facility (AlgaFarm). This microalga contained high amounts of protein (31.2 g/100 g), dietary fibres (24.6 g/100 g), digestible carbohydrates (18.1 g/100 g) and ashes (15.2 g/100 g), but low lipid content (7.04 g/100 g). The biomass displayed a balanced amount of essential amino acids, n-3 polyunsaturated fatty acids, and starch-like polysaccharides. Significant levels of chlorophyll (3.5 g/100 g), carotenoids (0.61 g/100 g), and vitamins (e.g., 79.2 mg ascorbic acid /100 g) were also found in the biomass. Conversely, pathogenic bacteria, heavy metals, cyanotoxins, mycotoxins, polycyclic aromatic hydrocarbons, and pesticides were absent. The biomass showed moderate antioxidant activity in several in vitro assays. Taken together, as the biomass produced has a balanced biochemical composition of macronutrients and (pro-)vitamins, lacking any toxic contaminants, these results suggest that this strain can be used for nutritional applications.
Collapse
|
138
|
Regan B, Boyle F, O'Kennedy R, Collins D. Evaluation of Molecularly Imprinted Polymers for Point-of-Care Testing for Cardiovascular Disease. SENSORS (BASEL, SWITZERLAND) 2019; 19:E3485. [PMID: 31395843 PMCID: PMC6720456 DOI: 10.3390/s19163485] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 07/29/2019] [Accepted: 08/06/2019] [Indexed: 12/13/2022]
Abstract
Molecular imprinting is a rapidly growing area of interest involving the synthesis of artificial recognition elements that enable the separation of analyte from a sample matrix and its determination. Traditionally, this approach can be successfully applied to small analyte (<1.5 kDa) separation/ extraction, but, more recently it is finding utility in biomimetic sensors. These sensors consist of a recognition element and a transducer similar to their biosensor counterparts, however, the fundamental distinction is that biomimetic sensors employ an artificial recognition element. Molecularly imprinted polymers (MIPs) employed as the recognition elements in biomimetic sensors contain binding sites complementary in shape and functionality to their target analyte. Despite the growing interest in molecularly imprinting techniques, the commercial adoption of this technology is yet to be widely realised for blood sample analysis. This review aims to assess the applicability of this technology for the point-of-care testing (POCT) of cardiovascular disease-related biomarkers. More specifically, molecular imprinting is critically evaluated with respect to the detection of cardiac biomarkers indicative of acute coronary syndrome (ACS), such as the cardiac troponins (cTns). The challenges associated with the synthesis of MIPs for protein detection are outlined, in addition to enhancement techniques that ultimately improve the analytical performance of biomimetic sensors. The mechanism of detection employed to convert the analyte concentration into a measurable signal in biomimetic sensors will be discussed. Furthermore, the analytical performance of these sensors will be compared with biosensors and their potential implementation within clinical settings will be considered. In addition, the most suitable application of these sensors for cardiovascular assessment will be presented.
Collapse
|
139
|
Eisenmann B, Czemmel S, Ziegler T, Buchholz G, Kortekamp A, Trapp O, Rausch T, Dry I, Bogs J. Rpv3-1 mediated resistance to grapevine downy mildew is associated with specific host transcriptional responses and the accumulation of stilbenes. BMC PLANT BIOLOGY 2019; 19:343. [PMID: 31387524 PMCID: PMC6685164 DOI: 10.1186/s12870-019-1935-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/11/2019] [Indexed: 05/05/2023]
Abstract
BACKGROUND European grapevine cultivars (Vitis vinifera spp.) are highly susceptible to the downy mildew pathogen Plasmopara viticola. Breeding of resistant V. vinifera cultivars is a promising strategy to reduce the impact of disease management. Most cultivars that have been bred for resistance to downy mildew, rely on resistance mediated by the Rpv3 (Resistance to P. viticola) locus. However, despite the extensive use of this locus, little is known about the mechanism of Rpv3-mediated resistance. RESULTS In this study, Rpv3-mediated defense responses were investigated in Rpv3+ and Rpv3- grapevine cultivars following inoculation with two distinct P. viticola isolates avrRpv3+ and avrRpv3-, with the latter being able to overcome Rpv3 resistance. Based on comparative microscopic, metabolomic and transcriptomic analyses, our results show that the Rpv3-1-mediated resistance is associated with a defense mechanism that triggers synthesis of fungi-toxic stilbenes and programmed cell death (PCD), resulting in reduced but not suppressed pathogen growth and development. Functional annotation of the encoded protein sequence of genes significantly upregulated during the Rpv3-1-mediated defense response revealed putative roles in pathogen recognition, signal transduction and defense responses. CONCLUSION This study used histochemical, transcriptomic and metabolomic analyses of Rpv3+ and susceptible cultivars inoculated with avirulent and virulent P. viticola isolates to investigate mechanism underlying the Rpv3-1-mediated resistance response. We demonstrated a strong correlation between the expressions of stilbene biosynthesis related genes, the accumulation of fungi-toxic stilbenes, pathogen growth inhibition and PCD.
Collapse
|
140
|
De Meyer S, Vanmeert F, Vertongen R, Van Loon A, Gonzalez V, Delaney J, Dooley K, Dik J, Van der Snickt G, Vandivere A, Janssens K. Macroscopic x-ray powder diffraction imaging reveals Vermeer's discriminating use of lead white pigments in Girl with a Pearl Earring. SCIENCE ADVANCES 2019; 5:eaax1975. [PMID: 31497648 PMCID: PMC6716954 DOI: 10.1126/sciadv.aax1975] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
Until the 19th century, lead white was the most important white pigment used in oil paintings. Lead white is typically composed of two crystalline lead carbonates: hydrocerussite [2PbCO3·Pb(OH)2] and cerussite (PbCO3). Depending on the ratio between hydrocerussite and cerussite, lead white can be classified into different subtypes, each with different optical properties. Current methods to investigate and differentiate between lead white subtypes involve invasive sampling on a microscopic scale, introducing problems of paint damage and representativeness. In this study, a 17th century painting Girl with a Pearl Earring (by Johannes Vermeer, c. 1665, collection of the Mauritshuis, NL) was analyzed with a recently developed mobile and noninvasive macroscopic x-ray powder diffraction (MA-XRPD) scanner within the project Girl in the Spotlight. Four different subtypes of lead white were identified using XRPD imaging at the macroscopic and microscopic scale, implying that Vermeer was highly discriminatory in his use of lead white.
Collapse
|
141
|
Arteaga-Marrero N, Villa E, González-Fernández J, Martín Y, Ruiz-Alzola J. Polyvinyl alcohol cryogel phantoms of biological tissues for wideband operation at microwave frequencies. PLoS One 2019; 14:e0219997. [PMID: 31344092 PMCID: PMC6657873 DOI: 10.1371/journal.pone.0219997] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 07/05/2019] [Indexed: 11/18/2022] Open
Abstract
The aim of this work is to provide a methodology to model the dielectric properties of human tissues based on phantoms prepared with an aqueous solution, in a semi-solid form, by using off-the-shelf components. Polyvinyl alcohol cryogel (PVA-C) has been employed as a novel gelling agent in the fabrication of phantoms for microwave applications in a wide frequency range, from 500 MHz to 20 GHz. Agar-based and deionized water phantoms have also been manufactured for comparison purposes. Mathematical models dependent on frequency and sucrose concentration are proposed to obtain the complex permittivity of the desired mimicked tissues. These models have been validated in the referred bandwidth showing a good agreement to experimental data for different sucrose concentrations. The PVA-C model provides a great performance as compared to agar, increasing the shelf-life of the phantoms and improving their consistency for contact-required devices. In addition, the feasibility of fabricating a multilayer phantom has been demonstrated with a two-layer phantom that exhibits a clear interface between each layer and its properties. Thus, the use of PVA-C extends the option for producing complex multilayer and multimodal phantoms.
Collapse
|
142
|
Giebler M, Radl S, Ules T, Griesser T, Schlögl S. Photopatternable Epoxy-Based Thermosets. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2350. [PMID: 31344852 PMCID: PMC6695657 DOI: 10.3390/ma12152350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/17/2019] [Accepted: 07/22/2019] [Indexed: 01/09/2023]
Abstract
The present work provides a comparative study on the photopatterning of epoxy-based thermosets as a function of network structure and network mobility. Local switching of solubility properties by light of a defined wavelength is achieved by exploiting versatile o-nitrobenzyl ester (o-NBE) chemistry. o-NBE derivatives with terminal epoxy groups are synthetized and thermally cured with different types of cycloaliphatic anhydrides via nucleophilic ring opening reaction. By varying the structure of the anhydride, glass transition temperature (Tg) and surface hardness are adjusted over a broad range. Once the network has been formed, the photolysis of the o-NBE groups enables a well-defined degradation of the 3D network. Fourier transform infrared (FT-IR) spectroscopy studies demonstrate that cleavage rate and cleavage yield increase with rising mobility of the network, which is either facilitated by inherent network properties (Tg below room temperature) or a simultaneous heating of the thermosets above their Tg. The formation of soluble species is evidenced by sol-gel analysis, revealing that low-Tg networks are prone to secondary photoreactions at higher exposure doses, which lead to a re-crosslinking of the cleaved polymer chains. The change in solubility properties is exploited to inscribe positive tone micropatterns within the thermosets by photolithographic techniques. Contrast curves show that the resist performance of rigid networks is superior to flexible ones, with a contrast of 1.17 and a resolution of 8 µm.
Collapse
|
143
|
Ferreira MT, Cardoso P, Borges PAV, Gabriel R, de Azevedo EB, Elias RB. Implications of climate change to the design of protected areas: The case study of small islands (Azores). PLoS One 2019; 14:e0218168. [PMID: 31194805 PMCID: PMC6563998 DOI: 10.1371/journal.pone.0218168] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 05/28/2019] [Indexed: 11/19/2022] Open
Abstract
Climate change is causing shifts in species distributions worldwide. Understanding how species distributions will change with future climate change is thus critical for conservation planning. Impacts on oceanic islands are potentially major given the disproportionate number of endemic species and the consequent risk that local extinctions might become global ones. In this study, we use species climate envelope models to evaluate the current and future potential distributions of Azorean endemic species of bryophytes, vascular plants, and arthropods on the Islands of Terceira and São Miguel in the Azores archipelago (Macaronesia). We examined projections of climate change effects on the future distributions of species with particular focus on the current protected areas. We then used spatial planning optimization software (PRION) to evaluate the effectiveness of protected areas at preserving species both in the present and future. We found that contractions of species distributions in protected areas are more likely in the largest and most populated island of São Miguel, moving from the coastal areas towards inland where the current protected areas are insufficient and inadequate to tackle species distribution shifts. There will be the need for a revision of the current protected areas in São Miguel to allow the sustainable conservation of most species, while in Terceira Island the current protected areas appear to be sufficient. Our study demonstrates the importance of these tools for informing long-term climate change adaptation planning for small islands.
Collapse
|
144
|
Tedesco S, Sica M, Ancillao A, Timmons S, Barton J, O’Flynn B. Accuracy of consumer-level and research-grade activity trackers in ambulatory settings in older adults. PLoS One 2019; 14:e0216891. [PMID: 31112585 PMCID: PMC6529154 DOI: 10.1371/journal.pone.0216891] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/30/2019] [Indexed: 11/23/2022] Open
Abstract
Wrist-worn activity trackers have experienced a tremendous growth lately and studies on the accuracy of mainstream trackers used by older adults are needed. This study explores the performance of six trackers (Fitbit Charge2, Garmin VivoSmart HR+, Philips Health Watch, Withings Pulse Ox, ActiGraph GT9X-BT, Omron HJ-72OITC) for estimating: steps, travelled distance, and heart-rate measurements for a cohort of older adults. Eighteen older adults completed a structured protocol involving walking tasks, simulated household activities, and sedentary activities. Less standardized activities were also included, such as: dusting, using a walking aid, or playing cards, in order to simulate real-life scenarios. Wrist-mounted and chest/waist-mounted devices were used. Gold-standards included treadmill, ECG-based chest strap, direct observation or video recording according to the activity and parameter. Every tracker showed a decreasing accuracy with slower walking speed, which resulted in a significant step under-counting. A large mean absolute percentage error (MAPE) was found for every monitor at slower walking speeds with the lowest reported MAPE at 2 km/h being 7.78%, increasing to 20.88% at 1.5 km/h, and 44.53% at 1 km/h. During household activities, the MAPE climbing up/down-stairs ranged from 8.38–19.3% and 10.06–19.01% (dominant and non-dominant arm), respectively. Waist-worn devices showed a more uniform performance. However, unstructured activities (e.g. dusting, playing cards), and using a walking aid represent a challenge for all wrist-worn trackers as evidenced by large MAPE (> 57.66% for dusting, > 67.32% when using a walking aid). Poor performance in travelled distance estimation was also evident during walking at low speeds and climbing up/down-stairs (MAPE > 71.44% and > 48.3%, respectively). Regarding heart-rate measurement, there was no significant difference (p-values > 0.05) in accuracy between trackers placed on the dominant or non-dominant arm. Concordant with existing literature, while the mean error was limited (between -3.57 bpm and 4.21 bpm), a single heart-rate measurement could be underestimated up to 30 beats-per-minute. This study showed a number of limitations of consumer-level wrist-based activity trackers for older adults. Therefore caution is required when used, in healthcare or in research settings, to measure activity in older adults.
Collapse
|
145
|
Porta Siegel T, Ekroos K, Ellis SR. Reshaping Lipid Biochemistry by Pushing Barriers in Structural Lipidomics. Angew Chem Int Ed Engl 2019; 58:6492-6501. [PMID: 30601602 PMCID: PMC6563696 DOI: 10.1002/anie.201812698] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Indexed: 12/14/2022]
Abstract
Lipidomics is a rapidly growing field with numerous examples showing the importance of lipid molecules throughout biology. It has also shed light onto the vast and complex functions performed by many lipids that possess an immense diversity in molecular structures. Mass spectrometry (MS) is the tool of choice for analyzing lipids and has been the key catalyst driving the field forward. However, MS does not yet permit true molecular lipidomics wherein the identification and quantification of lipids having defined molecular structures can be routinely achieved. Here we describe recent advances in MS-based lipidomics that allow access to higher levels of molecular information in lipidomics experiments. These advances will form a key piece of the puzzle as the field moves towards systems characterization of lipids at the molecular level.
Collapse
|
146
|
Chiboub O, Sifaoui I, Lorenzo-Morales J, Abderrabba M, Mejri M, Fernández JJ, Piñero JE, Díaz-Marrero AR. Spiralyde A, an Antikinetoplastid Dolabellane from the Brown Alga Dictyota spiralis. Mar Drugs 2019; 17:E192. [PMID: 30934651 PMCID: PMC6471066 DOI: 10.3390/md17030192] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/18/2019] [Accepted: 03/21/2019] [Indexed: 12/19/2022] Open
Abstract
Bioassay-guided fractionation of the antikinetoplastid extract of the brown alga Dictyota spiralis has led to the isolation of spiralyde A (1), a new dolabellane aldehyde, along with other five known related diterpenes (2⁻6). Their structures were determined by HRESIMS, 1D and 2D NMR spectroscopy, and comparison with data reported in the literature. The antiparasitic activity of all compounds was evaluated. Spiralyde A (1) and the known compound 3,4-epoxy-7,18-dolabelladiene (2) were the most active compounds against Leishmania amazonensis and Trypanosoma cruzi. Spiralyde A (1) was the most potent compound, comparable to benznidazole, the reference drug for trypanocidal activity.
Collapse
|
147
|
Briz-Cid N, Rial-Otero R, Cámara MA, Oliva J, Simal-Gandara J. Dissipation of Three Fungicides and Their Effects on Anthocyanins and Color of Monastrell Red Wines. Int J Mol Sci 2019; 20:E1447. [PMID: 30909373 PMCID: PMC6470954 DOI: 10.3390/ijms20061447] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 11/25/2022] Open
Abstract
The effect of fungicides on fermentation is of paramount importance to control the quality and safety of wines. In this work, the quality (enological parameters, color, phenolic content, antioxidant activity, and fungicide residues) of wines from Monastrell grapes fortified with iprovalicarb, mepanipyrim, and tetraconazole fungicides was evaluated. Along the winemaking process, initial residues of mepanipyrim and tetraconazole were removed in more than 90% while the dissipation of iprovalicarb was around 73%. Significant statistical differences were found in the presence of iprovalicarb and mepanipyrim residues, especially at the highest concentration assayed. For both fungicides, increases in the volatile acidity (between 4 and 8.6 times), the lactic acid content (between 8.6 and 20.5 times), the percentage of polymeric anthocyanins (between 1.3 and 1.7 times), and also a slight increase of the total phenolic index and the total anthocyanin content determined by spectrophotometry were observed. On the contrary, the total monomeric anthocyanins content decreased about 16.3% and 28.6% in the presence of iprovalicarb and mepanipyrim, respectively. These results could be related to a higher development of acetic acid or lactic bacteria in the presence of these fungicides. The color of the final wines was also different in comparison with the control, with a higher yellow component, color intensity, tonality, and hue angle because of pH changes in the medium. Tetraconazole fermentations had a more similar trend to the control wine, probably due to the lower concentration of this fungicide in the grape must at the initial time. No effects on the antioxidant activity was observed for any of the target fungicides. A multivariate statistical analysis was done to view the interrelationships between different variables (color and anthocyanins profile). The obtained model allowed the wines to be separated according to the fungicide treatment applied.
Collapse
|
148
|
Molina-Márquez A, Vila M, Vigara J, Borrero A, León R. The Bacterial Phytoene Desaturase-Encoding Gene ( CRTI) is an Efficient Selectable Marker for the Genetic Transformation of Eukaryotic Microalgae. Metabolites 2019; 9:E49. [PMID: 30871061 PMCID: PMC6468381 DOI: 10.3390/metabo9030049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 02/27/2019] [Accepted: 03/05/2019] [Indexed: 12/22/2022] Open
Abstract
Genetic manipulation shows great promise to further boost the productivity of microalgae-based compounds. However, selection of microalgal transformants depends mainly on the use of antibiotics, which have raised concerns about their potential impacts on human health and the environment. We propose the use of a synthetic phytoene desaturase-encoding gene (CRTIop) as a selectable marker and the bleaching herbicide norflurazon as a selective agent for the genetic transformation of microalgae. Bacterial phytoene desaturase (CRTI), which, unlike plant and algae phytoene desaturase (PDS), is not sensitive to norflurazon, catalyzes the conversion of the colorless carotenoid phytoene into lycopene. Although the expression of CRTI has been described to increase the carotenoid content in plant cells, its use as a selectable marker has never been testedin algae or in plants. In this study, a version of the CRTI gene adapted to the codon usage of Chlamydomonas has been synthesized, and its suitability to be used as selectable marker has been shown. The microalgae were transformed by the glass bead agitation method and selected in the presence of norflurazon. Average transformation efficiencies of 550 colonies µg-1 DNA were obtained. All the transformants tested had incorporated the CRTIop gene in their genomes and were able to synthesize colored carotenoids.
Collapse
|
149
|
Flamini G, Pistelli L, Nardoni S, Ebani VV, Zinnai A, Mancianti F, Ascrizzi R, Pistelli L. Essential Oil Composition and Biological Activity of "Pompia", a Sardinian Citrus Ecotype. Molecules 2019; 24:E908. [PMID: 30841559 PMCID: PMC6429368 DOI: 10.3390/molecules24050908] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 02/28/2019] [Accepted: 03/01/2019] [Indexed: 12/02/2022] Open
Abstract
Pompia is a Sardinian citrus ecotype whose botanical classification is still being debated. In the present study, the composition of Pompia peel essential oil (EO) is reported for the first time, along with that of the leaf EO, as a phytochemical contribution to the classification of this ecotype. The peel EO was tested for its antioxidant ability (with both the 2,2-diphenyl-1-picarylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays). Moreover, its antimicrobial activities were tested for the first time on dermatophytes (Microsporum canis, Microsporum gypseum, and Trichophyton mentagrophytes), on potentially toxigenic fungi (Fusarium solani, Aspergillus flavus, and Aspergillus niger) as well on bacteria (Escherichia coli, Staphylococcus aureus, and Staphylococcus pseudointermedius). The dominant abundance of limonene in the peel EO seems to distinguish Pompia from the Citrus spp. to which it had previously been associated. It lacks γ-terpinene, relevant in Citrus medica EO. Its relative content of α- and β-pinene is lower than 0.5%, in contrast to Citrus limon peel EO. Pompia peel and leaf EOs did not show significant amounts of linalool and linalyl acetate, which are typically found in Citrus aurantium. Pompia peel EO antioxidant activity was weak, possibly because of its lack of γ-terpinene. Moreover, it did not exert any antimicrobial effects either towards the tested bacteria strains, or to dermatophytes and environmental fungi.
Collapse
|
150
|
Saeed E, Piñeiro MM, Hermida-Merino C, Pastoriza-Gallego MJ. Determination of Transport Properties of Glycol-Based NanoFluids Derived from Surface Functionalized Graphene. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E252. [PMID: 30759883 PMCID: PMC6409526 DOI: 10.3390/nano9020252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 11/18/2022]
Abstract
Suspensions of nanometric-sized graphene platelets have been proposed recently as potential heat exchange working fluids, due to their remarkably enhanced thermal profile. Nevertheless, their use presents serious long-term stability issues. Due to this limitation, the nanoplatelets surface chemical functionalization has been postulated as a promising alternative to solve this problem. In this work, graphene nanoplatelets were functionalized following an oxidation-reduction process, and then dispersed in glycol as base fluid. The nanoparticles chemical profile was determined using XPS (x-ray photoelectron spectroscopy). The thermo-physical properties characterization of these nanofluids was performed by determining their viscosity and thermal conductivity, because of their impact on practical applications related with fluid flow and heat transfer. The effect of temperature and shearing time on viscosity were analyzed. Viscosity was measured with a stress-controlled rheometer. All samples show shear-thinning behavior with a very remarkable influence of temperature in their viscoelastic profile.
Collapse
|