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Analytical solutions for viscoelectric effects in electrokinetic nanochannels. Electrophoresis 2024; 45:676-686. [PMID: 38350722 DOI: 10.1002/elps.202300204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/21/2023] [Accepted: 12/18/2023] [Indexed: 02/15/2024]
Abstract
Understanding electrokinetic transport in nanochannels and nanopores is essential for emerging biological and electrochemical applications. The viscoelectric effect is an important mechanism implicated in the increase of local viscosity due to the polarization of a solvent under a strong electric field. However, most analyses of the viscoelectric effect have been limited to numerical analyses. In this work, we present a set of analytical solutions applicable to the physical description of viscoelectric effects in nanochannel electrokinetic systems. To achieve such closed-form solutions, we employ the Debye-Hückel approximation of small diffuse charge layer potentials compared to the thermal potential. We analyze critical parameters, including electroosmotic flow profiles, electroosmotic mobility, flow rate, and channel conductance. We compare and benchmark our analytical solutions with published predictions from numerical models. Importantly, we leverage these analytical solutions to identify essential thermophysical and nondimensional parameters that govern the behavior of these systems. We identify scaling parameters and relations among surface charge density, ionic strength, and nanochannel height.
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Appendectomy and asthma: a search for an association in older subjects. THE MEDICAL JOURNAL OF MALAYSIA 2024; 79:47-51. [PMID: 38287757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
INTRODUCTION Several risk factors found to be associated with postoperative complications and cancer surgery, which carry a significant morbidity risk to cancer patients. Therefore, prehabilitation is necessary to improve the functional capability and nutritional status of a patient prior to surgery, so that the patient can withstand any postoperative activity and associated deterioration. Thus, this study aims to assess the effectiveness of prehabilitation interventions on the functional status of patients with gastric and oesophageal cancer who underwent esophagectomy and gastrectomy. MATERIAL AND METHODS An interventional study was carried out among oesophageal and gastric cancer patients who had undergone surgery at the National Cancer Institute of Malaysia. The prehabilitation process took a maximum of two weeks, depending on the patient's optimisation before surgery. The prehabilitation is based on functional capacity (ECOG performance status), muscle function (handgrip strength), cardio-respiratory function (peak flow meter) and nutritional status (calorie and protein). Postoperative outcomes are measured based on the length of hospital stay, complications, and Clavien-Dindo Classification. RESULTS Thirty-one patients were recruited to undergo a prehabilitation intervention prior to gastrectomy (n=21) and esophagectomy (n=10). Demographically, most of the cancer patients were males (67.7%) with an ideal mean of BMI (23.5±6.0). Physically, the majority of them had physical class (ASA grade) Grade 2 (67.7%), ECOG performance status of 1 (61.3%) and SGA grade B (51.6%). The functional capacity and nutritional status showed a significant improvement after one week of prehabilitation interventions: peak expiratory flow meter (p<0.001), handgrip (p<0.001), ECOG performance (p<0.001), walking distance (p<0.001), incentive spirometry (p<0.001), total body calorie (p<0.001) and total body protein (p=0.004). However, those patients who required two weeks of prehabilitation for optimization showed only significant improvement in peak expiratory flow meter (p<0.001), handgrip (p<0.001), and incentive spirometry (p<0.001). Prehabilitation is significantly associated postoperatively with the length of hospital stay (p=0.028), complications (p=0.011) and Clavien-Dindo Classification (p=0.029). CONCLUSION Prehabilitation interventions significantly increase the functional capacity and nutritional status of cancer patients preoperatively; concurrently reducing hospital stays and complications postoperatively. However, certain cancer patients might require over two weeks of prehabilitation to improve the patient's functional capacity and reduce complications postoperatively.
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Gastrojejunostomy as a treatment for gastric outflow disorders in four adult horses. Aust Vet J 2023. [PMID: 37253644 DOI: 10.1111/avj.13249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 04/12/2023] [Accepted: 04/30/2023] [Indexed: 06/01/2023]
Abstract
Four adult horses with histories of moderate abdominal pain and inappetence were diagnosed with delayed gastric emptying and gastric impaction attributed to pyloroduodenal obstruction (three cases) or duodenitis (one case). A stapled side-to-side gastrojejunostomy was performed on all horses. Two horses returned to work and survived ≥3 years. One horse was euthanased 6 months post-surgery due to recurrent abdominal pain, and one was found dead 5 months postsurgery after an unattended foaling.
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A metagenomic-based study of two sites from the Barbadian reef system. CORAL REEFS (ONLINE) 2023; 42:359-366. [PMID: 37009568 PMCID: PMC10060342 DOI: 10.1007/s00338-022-02330-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 11/05/2022] [Indexed: 06/19/2023]
Abstract
UNLABELLED We study the microbiome of sea water collected from two locations of the Barbadian coral reefs. The two sites differ in several environmental and ecological variables including their endogenous benthic community and their proximity to urban development and runoffs from inland watersheds. The composition of the microbial communities was estimated using whole genome DNA shotgun sequencing with adjuvant measurements of chemical and environmental qualities. Although both sites exhibit a similar degree of richness, the less urbanized site (Maycocks reef at Hangman's Bay) has a strong concentration of phototrophs whereas the more urbanized location (Bellairs reef at Folkstone) is enriched for copiotrophs, macroalgal symbionts and marine-related disease-bearing organisms from taxa scattered across the tree of life. Our results are concordant with previous profiles of warm ocean surface waters, suggesting our approach captures the state of each coral reef site, setting the stage for longitudinal studies of marine microbiome dynamics in Barbados. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s00338-022-02330-y.
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Detection and Discrimination of Single Nucleotide Polymorphisms by Quantification of CRISPR-Cas Catalytic Efficiency. Anal Chem 2022; 94:15117-15123. [PMID: 36251847 DOI: 10.1021/acs.analchem.2c03338] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The specificity of CRISPR-Cas12 assays is attractive for the detection of single nucleotide polymorphisms (SNPs) implicated in, e.g., cancer and SARS-CoV-2 variants. Such assays often employ endpoint measurements of SNP or wild type (WT) activated Cas12 trans-cleavage activity; however, the fundamental kinetic effects of SNP versus WT activation remain unknown. We here show that endpoint-based assays are limited by arbitrary experimental choices (like used reporter concentration and assay duration) and work best for known target concentrations. More importantly, we show that SNP (versus WT) activation results in measurable kinetic shifts in the Cas12 trans-cleavage substrate affinity (KM) and apparent catalytic efficiency (kcat*/KM). To address endpoint-based assay limitations, we then develop an assay based on the quantification of Michaelis-Menten parameters and apply this assay to a 20 base pair WT target of the SARS-CoV-2 E gene. We find that the kcat*/KM measured for WT is 130-fold greater than the lowest kcat*/KM among all 60 measured SNPs (compared to a 4.8-fold for endpoint fluorescence of the same SNP). KM also offers a strong ability to distinguish SNPs, varies 27-fold over all the cases, and, importantly, is insensitive to the target concentration. Last, we point out trends among kinetic rates and SNP base and location within the CRISPR-Cas12 targeted region.
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Enzyme Kinetics and Detector Sensitivity Determine Limits of Detection of Amplification-Free CRISPR-Cas12 and CRISPR-Cas13 Diagnostics. Anal Chem 2022; 94:9826-9834. [PMID: 35759403 DOI: 10.1021/acs.analchem.2c01670] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Interest in CRISPR-Cas12 and CRISPR-Cas13 detection continues to increase as these detection schemes enable the specific recognition of nucleic acids. The fundamental sensitivity limits of these schemes (and their applicability in amplification-free assays) are governed by kinetic rates. However, these kinetic rates remain poorly understood, and their reporting has been inconsistent. We quantify kinetic parameters for several enzymes (LbCas12a, AsCas12a, AapCas12b, LwaCas13a, and LbuCas13a) and their corresponding limits of detection (LoD). Collectively, we present quantification of enzyme kinetics for 14 guide RNAs (gRNAs) and nucleic acid targets for a total of 50 sets of kinetic rate parameters and 25 LoDs. We validate the self-consistency of our measurements by comparing trends and limiting behaviors with a Michaelis-Menten trans-cleavage reaction kinetics model. For our assay conditions, activated Cas12 and Cas13 enzymes exhibit trans-cleavage catalytic efficiencies between order 105 and 106 M-1 s-1. For assays that use fluorescent reporter molecules (ssDNA and ssRNA) for target detection, the kinetic rates at the current assay conditions result in an amplification-free LoD in the picomolar range. The results suggest that successful detection of target requires cleavage (by an activated CRISPR enzyme) of the order of at least 0.1% of the fluorescent reporter molecules. This fraction of reporters cleaved is required to differentiate the signal from the background, and we hypothesize that this required fraction is largely independent of the detection method (e.g., endpoint vs reaction velocity) and detector sensitivity. Our results demonstrate the fundamental nature by which kinetic rates and background signal limit LoDs and thus highlight areas of improvement for the emerging field of CRISPR diagnostics.
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Abstract
Isotachophoresis (ITP) is a versatile electrophoretic technique that can be used for sample preconcentration, separation, purification, and mixing, and to control and accelerate chemical reactions. Although the basic technique is nearly a century old and widely used, there is a persistent need for an easily approachable, succinct, and rigorous review of ITP theory and analysis. This is important because the interest and adoption of the technique has grown over the last two decades, especially with its implementation in microfluidics and integration with on-chip chemical and biochemical assays. We here provide a review of ITP theory starting from physicochemical first-principles, including conservation of species, conservation of current, approximation of charge neutrality, pH equilibrium of weak electrolytes, and so-called regulating functions that govern transport dynamics, with a strong emphasis on steady and unsteady transport. We combine these generally applicable (to all types of ITP) theoretical discussions with applications of ITP in the field of microfluidic systems, particularly on-chip biochemical analyses. Our discussion includes principles that govern the ITP focusing of weak and strong electrolytes; ITP dynamics in peak and plateau modes; a review of simulation tools, experimental tools, and detection methods; applications of ITP for on-chip separations and trace analyte manipulation; and design considerations and challenges for microfluidic ITP systems. We conclude with remarks on possible future research directions. The intent of this review is to help make ITP analysis and design principles more accessible to the scientific and engineering communities and to provide a rigorous basis for the increased adoption of ITP in microfluidics.
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Millisecond timescale reactions observed via X-ray spectroscopy in a 3D microfabricated fused silica mixer. Corrigendum. JOURNAL OF SYNCHROTRON RADIATION 2022; 29:930. [PMID: 35511027 PMCID: PMC9070710 DOI: 10.1107/s1600577522002806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A figure in the article by Huyke et al. [(2021), J. Synchrotron Rad. 28, 1100-1113] is corrected.
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Increased exposure to loading is associated with decreased plantar soft tissue hardness in people with diabetes and neuropathy. Diabetes Res Clin Pract 2022; 187:109865. [PMID: 35398144 DOI: 10.1016/j.diabres.2022.109865] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/30/2022] [Accepted: 04/02/2022] [Indexed: 11/03/2022]
Abstract
AIMS Literature indicates that altered plantar loading in people with diabetes could trigger changes in plantar soft tissue biomechanics which, in turn, could affect the risk for ulceration. To stimulate more research in this area, this study uses in vivo testing to investigate the link between plantar loading and tissue hardness. METHODS Tissue hardness and plantar pressure distribution were measured for six plantar areas in 39 people with diabetes and peripheral neuropathy. RESULTS Spearman correlation analysis revealed that increased pressure time integral at the 1st metatarsal-head region (r = -0.354, n = 39, P = 0.027) or at the heel (r = -0.378, n = 39, P = 0.018) was associated with reduced hardness in the same regions. After accounting for confounding parameters, generalised estimating equations analysis also showed that 10% increase in pressure time integral at the heel was associated with ≈ 1 unit reduction in hardness in the same region. CONCLUSIONS For the first time, this study reveals that people with diabetes and neuropathy who tend to load their feet more heavily also tend to have plantar soft tissues with lower hardness. The observed difference in tissue hardness is likely to affect the tissue's vulnerability to overload injury. More research will be needed to explore the implications of the observed association for the risk of ulceration.
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Transplant Outcomes in Hearts with Moderate to Severe Left Ventricular Hypertrophy After the 2018 OPTN/UNOS Allocation Changes. J Heart Lung Transplant 2022. [DOI: 10.1016/j.healun.2022.01.1690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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A modular and reconfigurable open-channel gated device for the electrokinetic extraction of cell-free DNA assays. Anal Chim Acta 2022; 1200:339435. [DOI: 10.1016/j.aca.2022.339435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/06/2021] [Accepted: 01/02/2022] [Indexed: 11/01/2022]
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Species Abundance and Reaction Off-Rate Regulate Product Formation in Reactions Accelerated Using Isotachophoresis. Anal Chem 2021; 93:12541-12548. [PMID: 34492181 DOI: 10.1021/acs.analchem.1c01805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We present a model for second-order and pseudo-first-order reversible chemical reactions accelerated using peak-mode isotachophoresis (ITP). In such systems, ITP preconcentrates and co-locates the reactants between the leading and trailing electrolyte zones, and this significantly accelerates chemical reactions. Our model quantifies the effects of reaction rate constants and species abundance on product formation rate. We identify two key non-dimensional parameters, which are specific groupings of reaction rate constants, species concentrations, and influx rates. We then use a regular perturbation to study the effects of reverse reaction rate and relative species abundance (and relative rates of species accumulation) on production rate. We also use this perturbation method to derive an analytical expression for the quasi-steady-state production rate achievable by ITP. Our analytical models and numerical solutions are generally applicable to a wide range of systems, which use ITP to enhance reactions. The model is also an interesting case study of the complex coupling of electric field-driven species transport and reaction kinetics.
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Paracetamol hepatotoxicity: Discovering new drugs based on mechanistic insight from animal studies. Toxicol Lett 2021. [DOI: 10.1016/s0378-4274(21)00380-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Evaluation of potable groundwater zones identification based on WQI and GIS techniques in Adyar River basin, Chennai, Tamilnadu, India. ACTA ACUST UNITED AC 2021. [DOI: 10.1016/j.chnaes.2020.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Millisecond timescale reactions observed via X-ray spectroscopy in a 3D microfabricated fused silica mixer. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1100-1113. [PMID: 34212873 PMCID: PMC8284405 DOI: 10.1107/s1600577521003830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 04/09/2021] [Indexed: 06/13/2023]
Abstract
Determination of electronic structures during chemical reactions remains challenging in studies which involve reactions in the millisecond timescale, toxic chemicals, and/or anaerobic conditions. In this study, a three-dimensionally (3D) microfabricated microfluidic mixer platform that is compatible with time-resolved X-ray absorption and emission spectroscopy (XAS and XES, respectively) is presented. This platform, to initiate reactions and study their progression, mixes a high flow rate (0.50-1.5 ml min-1) sheath stream with a low-flow-rate (5-90 µl min-1) sample stream within a monolithic fused silica chip. The chip geometry enables hydrodynamic focusing of the sample stream in 3D and sample widths as small as 5 µm. The chip is also connected to a polyimide capillary downstream to enable sample stream deceleration, expansion, and X-ray detection. In this capillary, sample widths of 50 µm are demonstrated. Further, convection-diffusion-reaction models of the mixer are presented. The models are experimentally validated using confocal epifluorescence microscopy and XAS/XES measurements of a ferricyanide and ascorbic acid reaction. The models additionally enable prediction of the residence time and residence time uncertainty of reactive species as well as mixing times. Residence times (from initiation of mixing to the point of X-ray detection) during sample stream expansion as small as 2.1 ± 0.3 ms are also demonstrated. Importantly, an exploration of the mixer operational space reveals a theoretical minimum mixing time of 0.91 ms. The proposed platform is applicable to the determination of the electronic structure of conventionally inaccessible reaction intermediates.
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Abstract
CRISPR-diagnostic assays have gained significant interest in the last few years. This interest has grown rapidly during the current COVID-19 pandemic, where CRISPR-diagnostics have been frontline contenders for rapid testing solutions. This surge in CRISPR-diagnostic research prompts the following question: what exactly are the achievable limits of detection and associated assay times enabled by the kinetics of enzymes such as Cas12 and Cas13? To explore this question, we here present a model based on Michaelis-Menten enzyme kinetics theory applied to CRISPR enzymes. We use the model to develop analytical solutions for reaction kinetics and develop back-of-the-envelope criteria to validate and check for consistency in reported enzyme kinetic parameters. We applied our analyses to all studies known to us, which report Michaelis-Menten-type kinetic data for CRISPR-associated enzymes. These studies include all subtypes of Cas12 and Cas13 and orthologs. We found all but one study clearly violate at least two of our three rules and therefore present data that violate basic physical limits. We performed an experimental study of reaction kinetics of LbCas12a with both ssDNA and dsDNA activators and use these data to validate our model and its predicted scaling. The validated model is used to explore CRISPR reaction time scales and the degree of reaction completion for practically relevant target concentrations applicable to CRISPR-diagnostic assays. The results have broad implications for achievable limits of detection and assay times of emerging, amplification-free CRISPR-detection methods.
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Suppression of decoherence tied to electron-phonon coupling in telecom-compatible quantum dots: low-threshold reappearance regime for quantum state inversion. OPTICS LETTERS 2020; 45:6498-6501. [PMID: 33258845 DOI: 10.1364/ol.403590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/01/2020] [Indexed: 06/12/2023]
Abstract
We demonstrate suppression of dephasing tied to deformation potential coupling of confined electrons to longitudinal acoustic (LA) phonons in optical control experiments on large semiconductor quantum dots (QDs) with emission compatible with the low-dispersion telecommunications band at 1.3 µm. By exploiting the sensitivity of the electron-phonon spectral density to the size and shape of the QD, we demonstrate a fourfold reduction in the threshold pulse area required to enter the decoupled regime for exciton inversion using adiabatic rapid passage (ARP). Our calculations of the quantum state dynamics indicate that the symmetry of the QD wave function provides an additional means to engineer the electron-phonon interaction. Our findings will support the development of solid-state quantum emitters in future distributed quantum networks using semiconductor QDs.
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Simultaneous optical and infrared thermal imaging of isotachophoresis. Anal Chim Acta 2020; 1131:9-17. [PMID: 32928483 DOI: 10.1016/j.aca.2020.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/05/2020] [Accepted: 07/06/2020] [Indexed: 11/28/2022]
Abstract
Joule heating in isotachophoresis (ITP) can limit minimum assay times and efforts to scale up processed sample volumes. Despite its significance, the dynamics of Joule heating on spatiotemporal temperature fields in ITP systems have not been investigated. We here present novel measurements of spatiotemporal temperature and electromigration fields in ITP. To achieve this, we obtain simultaneous and registered optical and infrared thermal images of the ITP process. We conduct a series of experiments at constant current operation and vary the leading electrolyte concentration to study and highlight the importance of buffer-dependent ionic conductivity on the resulted temperature rise. The measurements demonstrate a substantial increase of temperature in the adjusted trailing electrolyte region, and the propagation of a thermal wave in the ITP channel with a velocity equal to that of the electromigration front. We present scaling of the experimental data that indicates the dependence of front velocity and temperature rise on current density and ionic conductivity. The current study has direct application to the design and optimization of scaled-up ITP systems and the validation of numerical models of Joule heating.
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Sarcoidosis, steroids and Strongyloides-what's the catch? Clin Microbiol Infect 2020; 27:S1198-743X(20)30561-9. [PMID: 32950714 PMCID: PMC7497548 DOI: 10.1016/j.cmi.2020.09.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/02/2020] [Accepted: 09/06/2020] [Indexed: 10/29/2022]
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SARS-CoV-2 antibodies in healthcare workers in a large university hospital, Kerala, India. Clin Microbiol Infect 2020; 27:481-483. [PMID: 32949718 PMCID: PMC7493758 DOI: 10.1016/j.cmi.2020.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/02/2020] [Accepted: 09/06/2020] [Indexed: 11/01/2022]
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Process design tools and techno-economic analysis for capacitive deionization. WATER RESEARCH 2020; 183:116034. [PMID: 32736269 DOI: 10.1016/j.watres.2020.116034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 05/03/2023]
Abstract
Capacitive deionization (CDI) devices use cyclical electrosorption on porous electrode surfaces to achieve water desalination. Process modeling and design of CDI systems requires accurate treatment of the coupling among input electrical forcing, input flow rates, and system responses including salt removal dynamics, water recovery, energy storage, and dissipation. Techno-economic analyses of CDI further require a method to calculate and compare between a produced commodity (e.g. desalted water) versus capital and operational costs of the system. We here demonstrate a new modeling and analysis tool for CDI developed as an installable Matlab program that allows direct numerical simulation of CDI dynamics and calculation of key performance and cost parameters. The program is provided for free and is used to run open-source Simulink models. The Simulink environment sends information to the program and allows for a drag and drop design space where users can connect CDI cells to relevant periphery blocks such as grid energy, battery, solar panel, waste disposal, and maintenance/labor cost streams. The program allows for simulation of arbitrary current forcing and arbitrary flow rate forcing of one or more CDI cells. We employ validated well-mixed reactor formulations together with a non-linear circuit model formulation that can accommodate a variety of electric double layer sub-models (e.g. for charge efficiency). The program includes a graphical user interface (GUI) to specify CDI plant parameters, specify operating conditions, run individual tests or parameter batch-mode simulations, and plot relevant results. The techno-economic models convert among dimensional streams of species (e.g. feed, desalted water, and brine), energy, and cost and enable a variety of economic estimates including levelized water costs.
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Anticorrosion Behavior of ZnO Nanoparticles Coated on Mild Steel in NaCl Solution. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2020; 20:4061-4068. [PMID: 31968421 DOI: 10.1166/jnn.2020.17526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This work focuses on the environment protected, ecological procedure by the combination of ZnO nanoparticles utilizing the extraction of Ocimum sanctum. The prepared nanoparticles are examined by different methods like Fourier-transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Energy Dispersive X-ray Analysis (EDAX). A systematic study has been made on the result of ZnO nano-coating for the corrosion behavior of mild steel. The ZnO nanoparticles of average diameter in the range 18-22 nm were coated on mild steel in nickel bath solution. The anticorrosion properties on the coated mild steel was carefully tested in 3.5% NaCl solution by performing potentio-dynamic polarization measurement and electrochemical impedance spectroscopy. Surface morphology of the coated mild steel immersed in corrosive solution was judged by using SEM with EDAX. The ZnO nano coating has shown a perfect protection against corrosion and the shielding capability is in the range between 86-95%. The incorporation of ZnO nanoparticles has upgraded the process of mild steel in all corrosion media are subjected to investigation.
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On the competition between mixing rate and uniformity in a coaxial hydrodynamic focusing mixer. Anal Chim Acta 2020; 1103:1-10. [PMID: 32081173 DOI: 10.1016/j.aca.2020.01.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/26/2019] [Accepted: 01/06/2020] [Indexed: 02/07/2023]
Abstract
Fast microfluidic mixers for use with line-of-sight integrating detection schemes pose unique challenges. Such detectors typically cannot discriminate signal from slow moving (e.g. near internal walls) and fast-moving portions of the fluid stream. This convolves reaction rate dynamics with fluid flow residence time dynamics. Further, the small cross sections of typical three-dimensional hydrodynamic focusing devices lead to lower detection signals. The current study focuses on achieving both small time scales of mixing and homogenous residence times. This is achieved by injecting sample through a center capillary and hydrodynamically focusing using a sheath flow within a tapered second capillary. The current design also features a third, larger coaxial capillary. The mixed stream flows into the large cross-section of this third capillary to decelerate and expand the stream by up to 14-fold to improve line-of-sight signal strength of reaction products. Hydrodynamic focusing, mixing, and expansion are studied using analytical and numerical models and also studied experimentally using a fluorescein-iodide quenching reaction. The experimentally validated models are used to explore trade-offs between mixing rate and uniformity. For the first time, this work presents detailed analysis of the Lagrangian time history of species transport during mixing inside coaxial capillaries to measure mixing nonuniformity. The mixing region enables order 100 μs mixing times and residence time widths of the same order (140 μs).
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Cardiovascular disease management in people with diabetes outside North America and Western Europe in 2006 and 2015. Diabet Med 2019; 36:878-887. [PMID: 30402961 PMCID: PMC6618273 DOI: 10.1111/dme.13858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/02/2018] [Indexed: 01/07/2023]
Abstract
AIM Optimal treatment of cardiovascular disease is essential to decrease mortality among people with diabetes, but information is limited on how actual treatment relates to guidelines. We analysed changes in therapeutic approaches to anti-hypertensive and lipid-lowering medications in people with Type 2 diabetes from 2006 and 2015. METHODS Summary data from clinical services in seven countries outside North America and Western Europe were collected for 39 684 people. Each site summarized individual-level data from outpatient medical records for 2006 and 2015. Data included: demographic information, blood pressure (BP), total cholesterol levels and percentage of people taking statins, anti-hypertensive medication (angiotensin-converting enzyme inhibitors, calcium channel blockers, angiotensin II receptor blockers, thiazide diuretics) and antiplatelet drugs. RESULTS From 2006 to 2015, mean cholesterol levels decreased in six of eight sites (range: -0.5 to -0.2), whereas the proportion with BP levels > 140/90 mmHg increased in seven of eight sites. Decreases in cholesterol paralleled increases in statin use (range: 3.1 to 47.0 percentage points). Overall, utilization of anti-hypertensive medication did not change. However, there was an increase in the use of angiotensin II receptor blockers and a decrease in angiotensin-converting enzyme inhibitors. The percentage of individuals receiving calcium channel blockers and aspirin remained unchanged. CONCLUSIONS Our findings indicate that control of cholesterol levels improved and coincided with increased use of statins. The percentage of people with BP > 140/90 mmHg was higher in 2015 than in 2006. Hypertension treatment shifted from using angiotensin-converting enzyme inhibitors to angiotensin II receptor blockers. Despite the potentially greater tolerability of angiotensin II receptor blockers, there was no associated improvement in BP levels.
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High water recovery and improved thermodynamic efficiency for capacitive deionization using variable flowrate operation. WATER RESEARCH 2019; 155:76-85. [PMID: 30831426 DOI: 10.1016/j.watres.2019.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 06/09/2023]
Abstract
Water recovery is a measure of the amount of treated water produced relative to the total amount of water processed through the system, and is an important performance metric for any desalination method. Conventional operating methods for desalination using capacitive deionization (CDI) have so far limited water recovery to be about 50%. To improve water recovery for CDI, we here introduce a new operating scheme based on a variable (in time) flow rate wherein a low flow rate during discharge is used to produce a brine volume which is significantly less than the volume of diluent produced. We demonstrate experimentally and study systematically this novel variable flowrate operating scheme in the framework of both constant current and constant voltage charge-discharge modes. We show that the variable flowrate operation can increase water recovery for CDI to very high values of ∼90% and can improve thermodynamic efficiency by about 2- to 3-fold compared to conventional constant flowrate operation. Importantly, this is achieved with minimal performance reductions in salt removal, energy consumption, and volume throughput. Our work highlights that water recovery can be readily improved for CDI at very minimal additional cost using simple flow control schemes.
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Performance metrics for the objective assessment of capacitive deionization systems. WATER RESEARCH 2019; 152:126-137. [PMID: 30665159 DOI: 10.1016/j.watres.2018.10.074] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/25/2018] [Accepted: 10/28/2018] [Indexed: 06/09/2023]
Abstract
In the growing field of capacitive deionization (CDI), a number of performance metrics have emerged to describe the desalination process. Unfortunately, the separation conditions under which these metrics are measured are often not specified, resulting in optimal performance at minimal removal. Here we outline a system of performance metrics and reporting conditions that resolves this issue. Our proposed system is based on volumetric energy consumption (Wh/m3) and throughput productivity (L/h/m2) reported for a specific average concentration reduction, water recovery, and feed salinity. To facilitate and rationalize comparisons between devices, materials, and operation modes, we propose a nominal standard separation of removing 5 mM from a 20 mM NaCl feed solution at 50% water recovery. We propose this particular separation as a standard, but emphasize that the rationale presented here applies irrespective of separation details. Using our proposed separation, we compare the desalination performance of a flow-through electrode (fte-CDI) cell and a flow between membrane (fb-MCDI) device, showing how significantly different systems can be compared in terms of generally desirable desalination characteristics. In general, we find that performance analysis must be considered carefully so to not allow for ambiguous separation conditions or the maximization of one metric at the expense of another. Additionally, for context and clarity, we discuss a number of important underlying performance indicators and cell characteristics that are not performance measures in and of themselves but can be examined to better understand differences in performance.
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Frequency analysis and resonant operation for efficient capacitive deionization. WATER RESEARCH 2018; 144:581-591. [PMID: 30092504 DOI: 10.1016/j.watres.2018.07.066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
Capacitive deionization (CDI) performance metrics can vary widely with operating methods. Conventional CDI operating methods such as constant current and constant voltage show advantages in either energy or salt removal performance, but not both. We here develop a theory around and experimentally demonstrate a new operation for CDI that uses sinusoidal forcing voltage (or sinusoidal current). We use a dynamic system modeling approach, and quantify the frequency response (amplitude and phase) of CDI effluent concentration. Using a wide range of operating conditions, we demonstrate that CDI can be modeled as a linear time invariant system. We validate this model with experiments, and show that a sinusoid voltage operation can simultaneously achieve high salt removal and strong energy performance, thus very likely making it superior to other conventional operating methods. Based on the underlying coupled phenomena of electrical charge (and ionic) transfer with bulk advection in CDI, we derive and validate experimentally the concept of using sinusoidal voltage forcing functions to achieve resonance-type operation for CDI. Despite the complexities of the system, we find a simple relation for the resonant time scale: the resonant time period (frequency) is proportional (inversely proportional) to the geometric mean of the flow residence time and the electrical (RC) charging time. Operation at resonance implies the optimal balance between absolute amount of salt removed (in moles) and dilution (depending on the feed volume processed), thus resulting in the maximum average concentration reduction for the desalinated water. We further develop our model to generalize the resonant time-scale operation, and provide responses for square and triangular voltage waveforms as two examples. To this end, we develop a general tool that uses Fourier analysis to construct CDI effluent dynamics for arbitrary input waveforms. Using this tool, we show that most of the salt removal (∼95%) for square and triangular voltage forcing waveforms is achieved by the fundamental Fourier (sinusoidal) mode. The frequency of higher Fourier modes precludes high flow efficiency for these modes, so these modes consume additional energy for minimal additional salt removed. This deficiency of higher frequency modes further highlights the advantage of DC-offset sinusoidal forcing for CDI operation.
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Abstract
We present a simple, top-down approach for the calculation of minimum energy consumption of electrosorptive ion separation using variational form of the (Gibbs) free energy. We focus and expand on the case of electrostatic capacitive deionization (CDI). The theoretical framework is independent of details of the double-layer charge distribution and is applicable to any thermodynamically consistent model, such as the Gouy-Chapman-Stern and modified Donnan models. We demonstrate that, under certain assumptions, the minimum required electric work energy is indeed equivalent to the free energy of separation. Using the theory, we define the thermodynamic efficiency of CDI. We show that the thermodynamic efficiency of current experimental CDI systems is currently very low, around 1% for most existing systems. We applied this knowledge and constructed and operated a CDI cell to show that judicious selection of the materials, geometry, and process parameters can lead to a 9% thermodynamic efficiency and 4.6 kT per removed ion energy cost. This relatively high thermodynamic efficiency is, to our knowledge, by far the highest thermodynamic efficiency ever demonstrated for traditional CDI. We hypothesize that efficiency can be further improved by further reduction of CDI cell series resistances and optimization of operational parameters.
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Self similarities in desalination dynamics and performance using capacitive deionization. WATER RESEARCH 2018; 140:323-334. [PMID: 29734040 DOI: 10.1016/j.watres.2018.04.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Charge transfer and mass transport are two underlying mechanisms which are coupled in desalination dynamics using capacitive deionization (CDI). We developed simple reduced-order models based on a mixed reactor volume principle which capture the coupled dynamics of CDI operation using closed-form semi-analytical and analytical solutions. We use the models to identify and explore self-similarities in the dynamics among flow rate, current, and voltage for CDI cell operation including both charging and discharging cycles. The similarity approach identifies the specific combination of cell (e.g. capacitance, resistance) and operational parameters (e.g. flow rate, current) which determine a unique effluent dynamic response. We here demonstrate self-similarity using a conventional flow between CDI (fbCDI) architecture, and we hypothesize that our similarity approach has potential application to a wide range of designs. We performed an experimental study of these dynamics and used well-controlled experiments of CDI cell operation to validate and explore limits of the model. For experiments, we used a CDI cell with five electrode pairs and a standard flow between (electrodes) architecture. Guided by the model, we performed a series of experiments that demonstrate natural response of the CDI system. We also identify cell parameters and operation conditions which lead to self-similar dynamics under a constant current forcing function and perform a series of experiments by varying flowrate, currents, and voltage thresholds to demonstrate self-similarity. Based on this study, we hypothesize that the average differential electric double layer (EDL) efficiency (a measure of ion adsorption rate to EDL charging rate) is mainly dependent on user-defined voltage thresholds, whereas flow efficiency (measure of how well desalinated water is recovered from inside the cell) depends on cell volumes flowed during charging, which is determined by flowrate, current and voltage thresholds. Results of experiments strongly support this hypothesis. Results show that cycle efficiency and salt removal for a given flowrate and current are maximum when average EDL and flow efficiencies are approximately equal. We further explored a range of CC operations with varying flowrates, currents, and voltage thresholds using our similarity variables to highlight trade-offs among salt removal, energy, and throughput performance.
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4-Methylpyrazole protects against acetaminophen hepatotoxicity in mice and in primary human hepatocytes. Hum Exp Toxicol 2018; 37:1310-1322. [PMID: 29739258 DOI: 10.1177/0960327118774902] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Liver injury due to acetaminophen (APAP) overdose is the major cause of acute liver failure in the United States. While treatment with N-acetylcysteine is the current standard of care for APAP overdose, anecdotal evidence suggests that administration of 4-methylpyrazole (4MP) may be beneficial in the clinic. The objective of the current study was to examine the protective effect of 4MP and its mechanism of action. Male C57BL/6J mice were co-treated with 300 mg/kg of APAP and 50 mg/kg of 4MP. The severe liver injury induced by APAP at 6 h as indicated by elevated plasma alanine aminotransferase activities, centrilobular necrosis, and nuclear DNA fragmentation was almost completely eliminated by 4MP. In addition, 4MP largely prevented APAP-induced activation of c-Jun N-terminal kinase (JNK), mitochondrial translocation of phospho-JNK and Bax, and the release of mitochondrial intermembrane proteins. Importantly, 4MP inhibited the generation of APAP protein adducts and formation of APAP-glutathione (GSH) conjugates and attenuated the depletion of the hepatic GSH content. These findings are relevant to humans because 4MP also prevented APAP-induced cell death in primary human hepatocytes. In conclusion, early treatment with 4MP can completely prevent liver injury after APAP overdose by inhibiting cytochrome P450 and preventing generation of the reactive metabolite.
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Evidence-based recommendations for insulin intensification strategies after basal insulin in type 2 diabetes. Diabetes Metab Syndr 2017; 11 Suppl 1:S507-S521. [PMID: 28433618 DOI: 10.1016/j.dsx.2017.03.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Indexed: 01/27/2023]
Abstract
Over the time due to progressive nature of diabetes, proactive intensification of the existing insulin therapy becomes imminent as it minimizes patients' exposure to chronic hypo/hyperglycaemia and reduces weight gain while achieving individualized glycaemic targets. This review focuses on the strength of evidence behind various options for intensification, primarily the insulins as also the GLP-1 analogues. The recommendations presented here are meant to serve as a guide for the physician managing type 2 diabetes patients requiring insulin intensification upon failing of basal insulin therapy.
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Can plantar soft tissue mechanics enhance prognosis of diabetic foot ulcer? Diabetes Res Clin Pract 2017; 126:182-191. [PMID: 28259007 DOI: 10.1016/j.diabres.2017.02.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/16/2017] [Accepted: 02/02/2017] [Indexed: 10/20/2022]
Abstract
AIM To investigate if the assessment of the mechanical properties of plantar soft tissue can increase the accuracy of predicting Diabetic Foot Ulceration (DFU). METHODS 40 patients with diabetic neuropathy and no DFU were recruited. Commonly assessed clinical parameters along with plantar soft tissue stiffness and thickness were measured at baseline using ultrasound elastography technique. 7 patients developed foot ulceration during a 12months follow-up. Logistic regression was used to identify parameters that contribute to predicting the DFU incidence. The effect of using parameters related to the mechanical behaviour of plantar soft tissue on the specificity, sensitivity, prediction strength and accuracy of the predicting models for DFU was assessed. RESULTS Patients with higher plantar soft tissue thickness and lower stiffness at the 1st Metatarsal head area showed an increased risk of DFU. Adding plantar soft tissue stiffness and thickness to the model improved its specificity (by 3%), sensitivity (by 14%), prediction accuracy (by 5%) and prognosis strength (by 1%). The model containing all predictors was able to effectively (χ2 (8, N=40)=17.55, P<0.05) distinguish between the patients with and without DFU incidence. CONCLUSION The mechanical properties of plantar soft tissue can be used to improve the predictability of DFU in moderate/high risk patients.
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Impact of lifestyle intervention in primary prevention of Type 2 diabetes did not differ by baseline age and BMI among Asian-Indian people with impaired glucose tolerance. Diabet Med 2016; 33:1700-1704. [PMID: 26773871 DOI: 10.1111/dme.13071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 11/11/2015] [Accepted: 01/11/2016] [Indexed: 01/28/2023]
Abstract
AIM To investigate whether the effectiveness of lifestyle interventions on the incidence of diabetes was influenced by the baseline age and BMI of the Asian-Indian participants with prediabetes. METHODS Pooled data, obtained from two of our Indian Diabetes Prevention Programmes (2006, n=236 and 2013, n=473; total N=709) which had similar baseline characteristics and intervention principles, were analysed. For the present secondary analysis we dichotomously categorized the participants' baseline age (<45 and ≥45 years) and BMI (<25.0 and ≥ 25.0 kg/m2 ). Glycaemic status was ascertained at 6-monthly intervals by oral glucose tolerance tests. The incidence rates of diabetes and relative risk reduction in both the intervention and the control group were calculated for categories of baseline age and BMI. Interactions between the intervention and baseline age and BMI on diabetes risk were also analysed. RESULTS Incident diabetes was diagnosed in 227 of the total 709 participants (32.0%) [control group 139 participants (38.8%) vs intervention group 88 participants (24.2%)] during the median follow-up period of 2 years. The overall relative risk reduction was 35.4% (95% CI 19.3-48.3). Lifestyle intervention was equally effective in both age groups [relative risk reduction in those aged <45 years: 43.7% (95% CI 19.8-60.5) and in those aged ≥ 45 years: 28.9% (95% CI 5.3-46.6) P for interaction = 0.52] and in categories of BMI [BMI <25 kg/m2 : 36.1% (95% CI 9.5-54.9); and BMI ≥ 25 kg/m2 : 34.8% (95% CI 12.9-51.2); P for interaction = 0.95]. CONCLUSIONS In Asian-Indian individuals with prediabetes, the effectiveness of lifestyle intervention was not modified by baseline age and BMI.
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Rates and predictors of hypoglycaemia in 27 585 people from 24 countries with insulin-treated type 1 and type 2 diabetes: the global HAT study. Diabetes Obes Metab 2016; 18:907-15. [PMID: 27161418 PMCID: PMC5031206 DOI: 10.1111/dom.12689] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/22/2016] [Accepted: 05/04/2016] [Indexed: 12/16/2022]
Abstract
AIMS To determine the global extent of hypoglycaemia experienced by patients with diabetes using insulin, as there is a lack of data on the prevalence of hypoglycaemia in developed and developing countries. METHODS This non-interventional, multicentre, 6-month retrospective and 4-week prospective study using self-assessment questionnaire and patient diaries included 27 585 patients, aged ≥18 years, with type 1 diabetes (T1D; n = 8022) or type 2 diabetes (T2D; n = 19 563) treated with insulin for >12 months, at 2004 sites in 24 countries worldwide. The primary endpoint was the proportion of patients experiencing at least one hypoglycaemic event during the observational period. RESULTS During the prospective period, 83.0% of patients with T1D and 46.5% of patients with T2D reported hypoglycaemia. Rates of any, nocturnal and severe hypoglycaemia were 73.3 [95% confidence interval (CI) 72.6-74.0], 11.3 (95% CI 11.0-11.6) and 4.9 (95% CI 4.7-5.1) events/patient-year for T1D and 19.3 (95% CI 19.1-19.6), 3.7 (95% CI 3.6-3.8) and 2.5 events/patient-year (95% CI 2.4-2.5) for T2D, respectively. The highest rates of any hypoglycaemia were observed in Latin America for T1D and Russia for T2D. Glycated haemoglobin level was not a significant predictor of hypoglycaemia. CONCLUSIONS We report hypoglycaemia rates in a global population, including those in countries without previous data. Overall hypoglycaemia rates were high, with large variations between geographical regions. Further investigation into these differences may help to optimize therapy and reduce the risk of hypoglycaemia.
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Direct mineral carbonation of steelmaking slag for CO2 sequestration at room temperature. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:7349-7359. [PMID: 26681331 DOI: 10.1007/s11356-015-5893-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 11/27/2015] [Indexed: 06/05/2023]
Abstract
Rapid increase of CO2 concentration in the atmosphere has forced the international community towards adopting actions to restrain from the impacts of climate change. Moreover, in India, the dependence on fossil fuels is projected to increase in the future, implying the necessity of capturing CO2 in a safe manner. Alkaline solid wastes can be utilized for CO2 sequestration by which its disposal issues in the country could also be met. The present work focuses to study direct mineral carbonation of steelmaking slag (SS) at room temperature and low-pressure conditions (<10 bar). Direct mineral carbonation of SS was carried out in a batch reactor with pure CO2 gas. The process parameters that may influence the carbonation of SS, namely, CO2 gas pressure, liquid to solid ratio (L/S) and reaction time were also studied. The results showed that maximum sequestration of SS was attained in the aqueous route with a capacity of 82 g of CO2/kg (6 bar, L/S ratio of 10 and 3 h). In the gas-solid route, maximum sequestration capacity of about 11.1 g of CO2/kg of SS (3 bar and 3 h) was achieved indicating that aqueous route is the better one under the conditions studied. These findings demonstrate that SS is a promising resource and this approach could be further developed and used for CO2 sequestration in the country. The carbonation process was evidenced using FT-IR, XRD, SEM and TG analysis.
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Is there a genetic predisposition to new-onset diabetes after kidney transplantation? SAUDI JOURNAL OF KIDNEY DISEASES AND TRANSPLANTATION 2016; 26:1113-20. [PMID: 26586047 DOI: 10.4103/1319-2442.168558] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Kidney transplant recipients may develop new-onset diabetes after transplantation (NODAT) and transplant-associated hyperglycemia (TAH) (NODAT or new-onset impaired glucose tolerance-IGT). We studied 251 consecutive renal transplant South Asian recipients for incidence of NODAT and its risk factors between June 2004 and January 2009. Pre-transplant glucose tolerance test (GTT) identified non-diabetics (n = 102, IGT-24, NGT-78) for analysis. Baseline immunosuppression along with either cyclosporine (CsA) (n = 70) or tacrolimus (Tac) (n = 32) was given. Patients underwent GTT 20 days (mean) post-transplant to identify NODAT, normal (N) or IGT. TAH was observed in 40.2% of the patients (40% in CsA and 40.6% in Tac) (P = 0.5). NODAT developed in 13.7% of the patients (12.9% in CsA and 15.6% in Tac) (P = 0.5). Overall, Hepatitis C (P = 0.007), human leukocyte antigen (HLA) B52 (P = 0.03) and lack of HLA A28 (A68/69) (P = 0.03) were associated with TAH. In the Tac group, higher Day 1 dosage (P <0.001), HLA A1 (P = 0.04), B13 (P = 0.03) and lack of DR2 (P = 0.004) increased the risk of TAH. In the CsA group, HLA A10 (P = 0.03), failure of triglyceride (P = 0.001) or low-density lipoprotein (LDL) (P = 0.03) to lower or high-density lipoprotein to rise (P = 0.001), and higher post-transplant LDL (P <0.001) and cholesterol levels (P = 0.02) were associated with NODAT or TAH. Post-transplant fasting plasma glucose on Day 1 had sensitivity-54.5%, specificity-50.1%, positive predictive value-18.1% and negative predictive value-84.8% for detecting NODAT. In conclusion, there is a genetic predisposition to NODAT and TAH in South Asia as seen by the HLA associations, and a predisposition exists to the individual diabetogenic effects of Tac and CsA based on HLA type. This could lead to more careful selection of calcineurin inhibitors based on HLA types in the South Asian population.
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Projected and Observed Aridity and Climate Change in the East Coast of South India under RCP 4.5. ScientificWorldJournal 2015; 2015:169761. [PMID: 26771002 PMCID: PMC4681802 DOI: 10.1155/2015/169761] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/03/2015] [Accepted: 11/08/2015] [Indexed: 12/03/2022] Open
Abstract
In the purview of global warming, the present study attempts to project changes in climate and quantify the changes in aridity of two coastal districts in south India under the RCP 4.5 trajectory. Projected climate change output generated by RegCM 4.4 model, pertaining to 14 grid points located within the study area, was analyzed and processed for this purpose. The meteorological parameters temperature and precipitations were used to create De Martonne Aridity Index, to assess the spatial distribution of aridity. The original index values ranged from 13.7 to 16.4 mm/°C, characterizing this area as a semidry climate. The outcome from the changed scenario analysis under RCP 4.5 showed that, during the end of the 21st century, the aridity may be increased more as the index values tend to reduce. The increasing trend in the drying phenomenon may be attributed to the rising of mean annual temperatures.
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Abstract
The craniofacial skeleton is derived from both neural crest cells and mesodermal cells; however, the majority of the bone, cartilage, and connective tissue is derived from the neural crest. Dentin sialophosphoprotein (DSPP) is a precursor protein that is expressed by the connective tissues of the craniofacial skeleton, namely, bone and dentin with high expression levels in the dentin matrix. Gene ablation studies have shown severe dental defects in DSPP-null mutant mice. Therefore, to elucidate the role of DSPP on the developing dental-craniofacial complex, we evaluated phenotypic changes in the structure of intramembranous bone and dentin mineralization using 3 different age groups of DSPP-null and wild-type mice. Results from micro-computed tomographic, radiographic, and optical microscopic analyses showed defective dentin, alveolar and calvarial bones, and sutures during development. The impaired mineralization of the cranial bone correlated well with low expression levels of Runx2, Col1, and OPN identified using calvarial cells from DSPP-null and wild-type mice in an in vitro culture system. However, the upregulation of MMP9, MMP2, FN, and BSP was observed. Interestingly, the null mice also displayed low serum phosphate levels, while calcium levels remained unchanged. Alizarin red and von Kossa staining confirmed the dysfunction in the terminal differentiation of osteoblasts obtained from the developing calvaria of DSPP-null mice. Immunohistochemical analysis of the developing molars showed changes in Runx2, Gli1, Numb, and Notch expression in the dental pulp cells and odontoblasts of DSPP-null mice when compared with wild-type mice. Overall, these observations provide insight into the role of DSPP in the normal development of the calvaria, alveolar bone, and dentin-pulp complex.
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Identification of a hypoxia-regulated miRNA signature in bladder cancer and a role for miR-145 in hypoxia-dependent apoptosis. Br J Cancer 2015; 113:634-44. [PMID: 26196183 PMCID: PMC4647685 DOI: 10.1038/bjc.2015.203] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/27/2015] [Accepted: 05/06/2015] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Hypoxia leads to the stabilisation of the hypoxia-inducible factor (HIF) transcription factor that drives the expression of target genes including microRNAs (miRNAs). MicroRNAs are known to regulate many genes involved in tumourigenesis. The aim of this study was to identify hypoxia-regulated miRNAs (HRMs) in bladder cancer and investigate their functional significance. METHODS Bladder cancer cell lines were exposed to normoxic and hypoxic conditions and interrogated for the expression of 384 miRNAs by qPCR. Functional studies were carried out using siRNA-mediated gene knockdown and chromatin immunoprecipitations. Apoptosis was quantified by annexin V staining and flow cytometry. RESULTS The HRM signature for NMI bladder cancer lines includes miR-210, miR-193b, miR-145, miR-125-3p, miR-708 and miR-517a. The most hypoxia-upregulated miRNA was miR-145. The miR-145 was a direct target of HIF-1α and two hypoxia response elements were identified within the promoter region of the gene. Finally, the hypoxic upregulation of miR-145 contributed to increased apoptosis in RT4 cells. CONCLUSIONS We have demonstrated the hypoxic regulation of a number of miRNAs in bladder cancer. We have shown that miR-145 is a novel, robust and direct HIF target gene that in turn leads to increased cell death in NMI bladder cancer cell lines.
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Geographic differences in the associations between impaired glucose regulation and cardiovascular risk factors among young adults. Diabet Med 2015; 32:497-504. [PMID: 25523878 DOI: 10.1111/dme.12674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/11/2014] [Indexed: 01/26/2023]
Abstract
AIMS To assess geographic differences in the association between BMI, blood pressure and lipid levels with impaired glucose regulation among young adults from various geographical regions. METHODS This was a cross-sectional study including data from 6987 participants aged ≤ 30 years from India, Singapore, Australia, Greenland, Kenya and Tanzania. Impaired glucose regulation was determined by the 75-g oral glucose tolerance test. For each geographical region, BMI, blood pressure and lipids were examined and compared between participants with normal glucose tolerance and those with impaired glucose regulation. Multiple logistic regression models were used to assess the association between risk factors and impaired glucose regulation. RESULTS Indian and East African people had a higher prevalence of impaired glucose regulation compared with participants from other regions, despite their lower BMI. Compared with the other regions, blood pressure was lower among Indian and Singaporean people but higher in those from Greenland. Greenlanders had the highest, while Indian and East-African people, had the lowest level of HDL cholesterol. BMI was positively associated with impaired glucose regulation in all regions, and there were no statistically significant geographic differences. In the Indian, Singaporean and Australian participants, there was a positive association between blood pressure and impaired glucose regulation. Triglycerides were positively associated with and HDL cholesterol had no association with impaired glucose regulation in all geographical regions. CONCLUSIONS Higher BMI and triglyceride levels were positively associated with prevalent impaired glucose regulation in all geographical regions. There were geographic differences in the association between impaired glucose regulation and blood pressure and lipids, probably reflecting environmental and genetic factors.
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Abstract
Remineralization of dentin during dental caries is of considerable clinical interest. Dentin matrix protein 1 (DMP1) is a non-collagenous calcium-binding protein that plays a critical role in biomineralization. In the present study, we tested if peptides derived from DMP1 can be used for dentin remineralization. Peptide pA (pA, MW = 1.726 kDa) and peptide pB (pB, MW = 2.185), containing common collagen-binding domains and unique calcium-binding domains, were synthesized by solid-phase chemistry. An extreme caries lesion scenario was created by collagenase digestion, and the biomineral-nucleating potential of these peptides was ascertained when coated on collagenase-treated dentin matrix and control, native human dentin matrix under physiological levels of calcium and phosphate. Scanning electron microscopy analysis suggests that peptide pB was an effective nucleator when compared with pA. However, a 1:4 ratio of pA to pB was determined to be ideal for dentin remineralization, based on hydroxyapatite (HA) morphology and calcium/phosphorus ratios. Interestingly, HA was nucleated on collagenase-challenged dentin with as little as 20 min of 1:4 peptide incubation. Electron diffraction confirmed the presence of large HA crystals that produced a diffraction pattern indicative of a rod-like crystal structure. These findings suggest that DMP1-derived peptides may be useful to modulate mineral deposition and subsequent formation of HA when exposed to physiological concentrations of calcium and phosphate.
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Hypertriglyceridaemic waist phenotype as a simple predictive marker of incident diabetes in Asian-Indian men with prediabetes. Diabet Med 2014; 31:1542-9. [PMID: 24910196 DOI: 10.1111/dme.12517] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/04/2014] [Accepted: 06/03/2014] [Indexed: 02/02/2023]
Abstract
AIM To determine prospectively the association of baseline hypertriglyceridaemic waist phenotype with incident diabetes in Asian-Indian men with impaired glucose tolerance. METHODS In a randomized 2-year diabetes prevention trial in 517 men with impaired glucose tolerance, 123 (23.8%) developed diabetes. Baseline anthropometric, metabolic and clinical variables were estimated. Associations of hypertriglyceridaemic waist phenotype (waist circumference ≥ 90cm and a serum triglyceride level of ≥ 1.7 mmol/l) with insulin resistance and incident diabetes were assessed using multiple linear regression and Cox's proportional hazard models, respectively. RESULTS Men with an isolated enlarged waistline and hypertriglyceridaemic waist phenotype had significantly higher BMI and percentage of total body fat compared with the group with normal waistline and triglyceride levels and the group with isolated hypertriglyceridaemia. The men with hypertriglyceridaemic waist phenotype had higher insulin resistance (mean ± sd homeostasis model assessment of insulin resistance value: 3.6 ± 1.5) compared with those in the isolated enlarged waistline, the isolated hypertriglyceridaemia or the normal waistline and triglyceride level groups (3.1 ± 1.4, 2.7 ± 1.0 and 2.5 ± 1.1, respectively, all P < 0.05 compared with hypertriglyceridaemic waist phenotype). Multiple linear regression analyses showed that hypertriglyceridaemic waist phenotype was significantly associated with insulin resistance after adjusting for age, BMI, family history, percentage of total body fat, smoking, alcohol intake, 2-h plasma glucose and HDL cholesterol level. Hypertriglyceridaemic waist phenotype was independently associated with incident diabetes after adjusting for the above confounders and gamma-glutamyl transferase (hazard ratio 1.49, 95% CI 1.01-2.21; P = 0.047). The association of hypertriglyceridaemic waist phenotype with incident diabetes was abolished when insulin resistance was introduced into the model (hazard ratio 1.39, 95% CI 0.092-2.10; P=0.12). CONCLUSIONS Hypertriglyceridaemic waist phenotype is a simple clinical proxy measurement for insulin resistance and is strongly associated with incident diabetes in Asian-Indian men with impaired glucose tolerance.
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Know the signs and symptoms of diabetes. Indian J Med Res 2014; 140:579-81. [PMID: 25579136 PMCID: PMC4311308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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An appraisal of physico-chemical and microbiological characteristics of Nanmangalam Reserve Forest soil. JOURNAL OF ENVIRONMENTAL BIOLOGY 2014; 35:1137-1144. [PMID: 25522517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A detailed evaluation was performed on the soils of Nanmangalam Reserve Forest (NRF) in order to understand its physico-chemical, microbiological and enzymatic characteristics. The results of analysis showed that soil pH was directly proportional to the soil depth and the soil moisture content was irreversibly related to varying soil depth. Soil organic carbon was positively correlated with (p < 0.01) with total nitrogen, total bacterial count, cellulytic microbes, nitrogen-fixing bacteria, microbial biomass carbon, dehydrogenase activity and soil respiration. During summer, microbial population in the organic layer was more diverse than in the deepest layer. Analysis showed that NRF had low organic carbon content (less than 1%), microbial biomass, nutrient and functional microbes. The overall results of the analysis reinstate that Nanmangalam forest soil is undergoing degradation.
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Abstract
Background: Cut-off values for endometrial thickness (ET) in asymptomatic postmenopausal woman have been standardized. However, there are no comprehensive studies to document how various factors can influence the ET after the age of menopause. Aim: To study the various factors influencing the ET in postmenopausal women. Subjects and Methods: This was a prospective observational study. A total of 110 postmenopausal women underwent detailed history taking, clinical examination, and transvaginal scan for uterine volume and ovarian volume. The volumes were calculated by using ellipsoid formula: Width × thickness × height × 0.523. The variation in ET with respect to the influencing factors such as age, duration of menopause, parity, body mass index (BMI), medical illness like diabetes/hypertension, drugs like tamoxifen, presence of myoma, uterine volume, ovarian volume, and serum estradiol (in selected patients) were measured. Descriptive analysis was performed using SPSS software (version 16, Chicago II, USA) to obtain mean, standard deviation (SD), 95% confidence intervals (CIs) and inter quartile ranges. Comparison of means was carried out using analysis of variance. Results: The mean (SD) age of the patients was 55.4 (6.91) years (95% CI, 54.1, 56.7). The mean (SD) age at menopause was 47.95 (3.90) years (95% CI, 47.2, 48.7) and the mean (SD) duration of menopause was 7.27 (6.65) years (95% CI, 6.01, 8.53). The mean (SD) ET was 3.8 (2.3) mm (95% CI, 3.36, 4.23). Medical illness like diabetes and hypertension did not alter the ET. ET increased as BMI increased and it was statistically significant. The presence of myoma increased uterine volume significantly and was associated with thick endometrial stripe. Similarly, whenever the ovaries were visualized and as the ovarian volume increased, there was an increase in ET. When ET was > 4 mm (n = 37), they were offered endocel, of which 16 agreed to undergo the procedure. None were found to have endometrial cancer. Conclusion: This study suggests that parity, BMI, presence of myoma, tamoxifen usage, uterine volume, ovarian volume and serum estradiol influence the ET in postmenopausal women.
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Understanding the safety of the new ultra long acting basal insulin. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 2014; 62:35-42. [PMID: 25330630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Hypoglycaemia is a key safety concern in diabetes management. It is potentially dangerous and the fear of hypoglycaemia may lead to sub-optimal dosing and inadequate glycaemic control. On the other hand, hypoglycaemia may generate adverse effects and disease complications, will compromise the quality of life and will substantially increase the economic burden of treatment budged. Today, treat to target clinical trial designs are mandate for clinical development of any newer anti-diabetic medication. While similar glycaemic targets are expected to be achieved by test and comparator, the newer molecules are definitely expected to show advantage over standard comparator in terms of reduction in frequency and severity of hypoglycaemia. An ultra-long acting basal analogue insulin degludec (IDeg), has been recently approved for the treatment of type 2 and type 1 diabetes mellitus (T2DM and T1DM). The pooled patient-level data for self-reported hypoglycaemia from seven phase 3a trials with IDeg has shown significantly lower episodes of nocturnal confirmed and numerical low overall confirmed hypoglycaemia with IDeg, compared to Insulin glargine (IGlar), which was more pronounced during maintenance phase of treatment in all populations. The most plausible explanation being that, the flat peakless profile of IDeg with least glycaemic variability leads to less hypoglycaemia and adds to the safety profile of this ultra-long acting insulin. The real life practice will further validate the findings of clinical trials.
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Abstract
The major phosphoprotein in dentin is the aspartic acid and serine-rich protein called dentin phosphophoryn (DPP). DPP appears to be synthesized as a part of a larger compound protein, dentin sialophosphoprotein (DSPP). DSPP has never been isolated or detected in dentin extracts. It is now evident that DSPP is a chimeric protein composed of 3 parts: dentin sialoprotein (DSP), DPP, and dentin glycoprotein (DGP). Previous reports have suggested that the BMP1 protease is responsible for processing DSPP. However, unequal amounts of these products are present in the dentin matrix. Here, we provide evidence for an internal ribosome entry site in the DSPP gene that directs the synthesis of DPP. This mechanism would account for unequal amounts of intracellular DSP and DPP. The internal ribosomal entry site (IRES) activity varied in different cell types, suggesting the presence of additional regulatory elements during the translational regulation of DPP. Further, we provide evidence that DPP is transported to the extracellular matrix (ECM) through exosomes. Using tissue recombination and lentivirus-mediated gain-of-function approaches, we also demonstrate that DPP is essential for the formation of well-defined tooth structures with mineralized dentin matrix.
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Estimation of quality of life in haemodialysis patients. Indian J Pharm Sci 2013; 74:583-7. [PMID: 23798788 PMCID: PMC3687932 DOI: 10.4103/0250-474x.110624] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Revised: 12/10/2012] [Accepted: 12/16/2012] [Indexed: 12/26/2022] Open
Abstract
Since haemodialysis is an expensive treatment modality for chronic renal failure patients, it is very essential to assess the outcome of therapy in terms of quality of life. The primary objective of the study was to estimate the effect of patient counselling in quality of life of end stage renal disease patients opting haemodialysis using World Health Organisation Quality of life scale and to assess the variables affecting the quality of life of these patients. Quality of life was determined by World Health Organisation Quality of life scale questionnaire comprised of 26 items which measures four domains: physical, psychological, social and environmental domain. A total of 81 patients were selected and divided into test and control group and the test group patients received counselling regarding their disease, use of medications, importance of adherence and the complications experienced during and after dialysis. The quality of life data was collected at the interval of 1, 2, 3, 6 and 12 months and the patients were counselled at each interval. The demographic profiles revealed that majority of the patients were in the age group of 31-50 and there exists a male predominance. About the socioeconomic status, upper middle class people were mostly affected. Assessment of impact of patient counselling in the quality of life of haemodialysis indicated a significant improvement in each domain after counselling. And also found that the psychological domain showed a significant increase in the score compared to others. Patient counselling helped to gain benefits in terms of improvement in quality of life and delayed progression of renal failure. Early recognition and prevention is necessary to improve the quality of life of chronic renal failure patients. Patient counselling should be made mandatory by incorporating clinical pharmacist in the nephrology team to make the patient understand his illness and modifications in lifestyle also create a positive environment and result in better quality of life.
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