138 research outputs found

    Quantitative Structure-Activity Relationship Analysis of the Anticonvulsant Activity of Some Benzylacetamides Based on Genetic Algorithm-Based Multiple Linear Regression

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    Purpose: To develop the quantitative structure-activity relationship (QSAR) for predicting the anticonvulsant activity of α-substituted acetamido-N-benzylacetamide derivatives.Methods: AM1 semiempirical quantum chemical calculation method was used to find the optimum 3D geometry of the studied molecules. Two types of molecular descriptors, including the 2D autocorrelation and GETAWAY descriptors, were used to derive a quantitative relation between anticonvulsant activity and structural properties. The relevant molecular descriptors were selected by genetic algorithm-based multiple linear regression (GA-MLR) approach.Results: The high value of the correlation coefficient, R2 (0.900), indicate that the model was satisfactory.Conclusion: The proposed model has good stability, robustness and predictability when verified by internal and external validation.Keywords: Anticonvulsant, Benzylacetamides, 2D Autocorrelation, Quantitative structure-activity relationships, Multiple linear regression

    A combination of three surface modifiers for the optimal generation and application of natural hybrid nanopigments in a biodegradable resin

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    Our purpose was to improve the thermal, mechanical and optimal properties of an epoxy bioresin using optimum hybrid natural pigments previously synthesised in our lab. Next, we searched for the best combinations of factors in the synthesis of natural hybrid nanopigments and then incorporated them into the bioresin. We combined three structural modifiers in the nanopigment synthesis, surfactant, coupling agent (silane) and a mordant salt (alum), selected to replicate mordant textile dyeing with natural dyes. We used Taguchi s design L8 to seek final performance optimisation. We selected three natural dyes, chlorophyll, beta-carotene and beetroot extract, and used two laminar nanoclay types, montmorillonite and hydrotalcite. The thermal, mechanical and colorimetric characterisation of the composite obtained by mixing natural hybrid nanopigments (bionanocomposite) was made. The natural dye interactions with both nanoclays improved the thermal stabilities, colour performance and UV VIS light exposure stability of natural dyes and bioresins. The best bionanocomposite materials were found in an acidic pH [3, 4] environment and by modifying nanoclays with mordant and surfactant during the nanopigment synthesis processWe thank the Spanish Ministry of Economy and Competitiveness for funding Projects DPI2011-30090-C02-02 and DPI2015-68514-R.Micó Vicent, B.; Jordán Núñez, J.; Martinez Verdu, FM.; Balart Gimeno, RA. (2017). A combination of three surface modifiers for the optimal generation and application of natural hybrid nanopigments in a biodegradable resin. Journal of Materials Science. 52(2):889-898. https://doi.org/10.1007/s10853-016-0384-8S889898522Majdzadeh-Ardakani K, Nazari B (2010) Improving the mechanical properties of thermoplastic starch/poly(vinyl alcohol)/clay nanocomposites. 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Factors influencing thermal stability and mechanisms of thermal stability improvement. Thermochim Acta 453(2):75–96. doi: 10.1016/j.tca.2006.11.002Park HM, Lee WK, Park CY, Cho WJ, Ha CS (2003) Environmentally friendly polymer hybrids Part I Mechanical, thermal, and barrier properties of thermoplastic starch/clay nanocomposites. J Mater Sci 38(5):909–915. doi: 10.1023/a:1022308705231Porter D, Metcalfe E, Thomas MJK (2000) Nanocomposite fire retardants—a review. Fire Mater 24(1):45–52. doi: 10.1002/(sici)1099-1018(200001/02)24:13.0.co;2-sRay SS, Okamoto M (2003) Polymer/layered silicate nanocomposites: a review from preparation to processing. Prog Polym Sci 28(11):1539–1641. doi: 10.1016/j.progpolymsci.2003.08.002Gao D, Li R, Lv B, Ma J, Tian F, Zhang J (2015) Flammability, thermal and physical-mechanical properties of cationic polymer/montmorillonite composite on cotton fabric. Compos B Eng 77:329–337. doi: 10.1016/j.compositesb.2015.03.061LeBaron PC, Wang Z, Pinnavaia TJ (1999) Polymer-layered silicate nanocomposites: an overview. Appl Clay Sci 15(1–2):11–29. doi: 10.1016/s0169-1317(99)00017-4Karuntarut Sermsantiwanita SP (2012) Preparation of bio-based nanocomposite emulsions: effect of clay type. Prog Org Coat 74:660–666Pascual J, Fages E, Fenollar O, Garcia D, Balart R (2009) Influence of the compatibilizer/nanoclay ratio on final properties of polypropylene matrix modified with montmorillonite-based organoclay. Polym Bull 62(3):367–380. doi: 10.1007/s00289-008-0018-7Beltrán MI, Benavente V, Marchante V, Marcilla A (2013) The influence of surfactant loading level in a montmorillonite on the thermal, mechanical and rheological properties of EVA nanocomposites. Appl Clay Sci 83–84:153–161. doi: 10.1016/j.clay.2013.08.028Bitinis N, Verdejo R, Maya EM, Espuche E, Cassagnau P, Lopez-Manchado MA (2012) Physicochemical properties of organoclay filled polylactic acid/natural rubber blend bionanocomposites. Compos Sci Technol 72(2):305–313. doi: 10.1016/j.compscitech.2011.11.018Sanchez-Garcia MD, Lopez-Rubio A, Lagaron JM (2010) Natural micro and nanobiocomposites with enhanced barrier properties and novel functionalities for food biopackaging applications. Trends Food Sci Technol 21(11):528–536. doi: 10.1016/j.tifs.2010.07.008Huskić M, Žigon M, Ivanković M (2013) Comparison of the properties of clay polymer nanocomposites prepared by montmorillonite modified by silane and by quaternary ammonium salts. Appl Clay Sci 85:109–115. doi: 10.1016/j.clay.2013.09.004Osman MA, Rupp JEP, Suter UW (2005) Effect of non-ionic surfactants on the exfoliation and properties of polyethylene-layered silicate nanocomposites. Polymer 46(19):8202–8209. doi: 10.1016/j.polymer.2005.06.101Wang H, Fang P, Chen Z, Wang S, Xu Y, Fang Z (2008) Effect of silane grafting on the microstructure of high-density polyethylene/organically modified montmorillonite nanocomposites. Polym Int 57(1):50–56. doi: 10.1002/pi.2310Montgomery DC (2008) Design and analysis of experiments. Wiley, HobokenBaena-Murillo E, Micó-Vicent B, Martínez-Verdú FM (2013) Method for the synthesis of nanostructured hybrid pigments having properties that can be syntonized. https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2013110841&recNum=229&docAn=ES2013070026&queryString=(ANA:ES)&maxRec=25813Kohno Y, Inagawa M, Ikoma S, Shibata M, Matsushima R, Fukuhara C, Tomita Y, Maeda Y, Kobayashi K (2011) Stabilization of a hydrophobic natural dye by intercalation into organo-montmorillonite. Appl Clay Sci 54(3):202–205. doi: 10.1016/j.clay.2011.09.001Kaneko Y, Iyi N, Bujdak J, Sasai R, Fujita T (2004) Effect of layer charge density on orientation and aggregation of a cationic laser dye incorporated in the interlayer space of montmorillonites. J Colloid Interface Sci 269(1):22–25. doi: 10.1016/s0021-9797(03)00602-7Silva AA, Dahmouche K, Soares BG (2011) Nanostructure and dynamic mechanical properties of silane-functionalized montmorillonite/epoxy nanocomposites. Appl Clay Sci 54(2):151–158. doi: 10.1016/j.clay.2011.08.002Park S-J, Kim B-J, Seo D-I, Rhee K-Y, Lyu Y-Y (2009) Effects of a silane treatment on the mechanical interfacial properties of montmorillonite/epoxy nanocomposites. Mater Sci Eng A 526(1–2):74–78. doi: 10.1016/j.msea.2009.07.023Khraisheh MAM, Al-Ghouti MA, Allen SJ, Ahmad MN (2005) Effect of OH and silanol groups in the removal of dyes from aqueous solution using diatomite. Water Res 39(5):922–932. doi: 10.1016/j.watres.2004.12.008Fahn R, Fenderl K (1983) Reaction-products of organic-dye molecules with acid-treated montmorillonite. Clay Miner 18(4):447–458. doi: 10.1180/claymin.1983.018.4.10Kohno Y, Totsuka K, Ikoma S, Yoda K, Shibata M, Matsushima R, Tomita Y, Maeda Y, Kobayashi K (2009) Photostability enhancement of anionic natural dye by intercalation into hydrotalcite. J Colloid Interface Sci 337(1):117–121. doi: 10.1016/j.jcis.2009.04.065Capilla P, Pujol J (2002) Fundamentos de Colorimetría. Universitat de ValenciaGilabert EJ, Verdú FMM (2007) Medida de la luz y el color. Editorial de la UPV. In: Color psicofísico, pp 185–221Zhao H, Nagy KL (2004) Dodecyl sulfate–hydrotalcite nanocomposites for trapping chlorinated organic pollutants in water. J Colloid Interface Sci 274(2):613–624. doi: 10.1016/j.jcis.2004.03.05

    Enzymatic Depilation of Animal Hide: Identification of Elastase (LasB) from Pseudomonas aeruginosa MCM B-327 as a Depilating Protease

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    Conventional leather processing involving depilation of animal hide by lime and sulphide treatment generates considerable amounts of chemical waste causing severe environmental pollution. Enzymatic depilation is an environmentally friendly process and has been considered to be a viable alternative to the chemical depilation process. We isolated an extracellular protease from Pseudomonas aeruginosa strain MCM B-327 with high depilation activity using buffalo hide as a substrate. This 33 kDa protease generated a peptide mass fingerprint and de novo sequence that matched perfectly with LasB (elastase), of Pseudomonas aeruginosa. In support of this data a lasB mutant of MCM B-327 strain lacked depilatory activity and failed to produce LasB. LasB heterologously over-produced and purified from Escherichia coli also exhibited high depilating activity. Moreover, reintroduction of the lasB gene to the P. aeruginosa lasB mutant via a knock-in strategy also successfully restored depilation activity thus confirming the role of LasB as the depilating enzyme

    From Cleanroom to Desktop: Emerging Micro-Nanofabrication Technology for Biomedical Applications

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    This review is motivated by the growing demand for low-cost, easy-to-use, compact-size yet powerful micro-nanofabrication technology to address emerging challenges of fundamental biology and translational medicine in regular laboratory settings. Recent advancements in the field benefit considerably from rapidly expanding material selections, ranging from inorganics to organics and from nanoparticles to self-assembled molecules. Meanwhile a great number of novel methodologies, employing off-the-shelf consumer electronics, intriguing interfacial phenomena, bottom-up self-assembly principles, etc., have been implemented to transit micro-nanofabrication from a cleanroom environment to a desktop setup. Furthermore, the latest application of micro-nanofabrication to emerging biomedical research will be presented in detail, which includes point-of-care diagnostics, on-chip cell culture as well as bio-manipulation. While significant progresses have been made in the rapidly growing field, both apparent and unrevealed roadblocks will need to be addressed in the future. We conclude this review by offering our perspectives on the current technical challenges and future research opportunities

    Global, regional, and national incidence, prevalence, and mortality of HIV, 1980–2017, and forecasts to 2030, for 195 countries and territories: a systematic analysis for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017

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    Background Understanding the patterns of HIV/AIDS epidemics is crucial to tracking and monitoring the progress of prevention and control efforts in countries. We provide a comprehensive assessment of the levels and trends of HIV/AIDS incidence, prevalence, mortality, and coverage of antiretroviral therapy (ART) for 1980–2017 and forecast these estimates to 2030 for 195 countries and territories. Methods We determined a modelling strategy for each country on the basis of the availability and quality of data. For countries and territories with data from population-based seroprevalence surveys or antenatal care clinics, we estimated prevalence and incidence using an open-source version of the Estimation and Projection Package—a natural history model originally developed by the UNAIDS Reference Group on Estimates, Modelling, and Projections. For countries with cause-specific vital registration data, we corrected data for garbage coding (ie, deaths coded to an intermediate, immediate, or poorly defined cause) and HIV misclassification. We developed a process of cohort incidence bias adjustment to use information on survival and deaths recorded in vital registration to back-calculate HIV incidence. For countries without any representative data on HIV, we produced incidence estimates by pulling information from observed bias in the geographical region. We used a re-coded version of the Spectrum model (a cohort component model that uses rates of disease progression and HIV mortality on and off ART) to produce age-sex-specific incidence, prevalence, and mortality, and treatment coverage results for all countries, and forecast these measures to 2030 using Spectrum with inputs that were extended on the basis of past trends in treatment scale-up and new infections. Findings Global HIV mortality peaked in 2006 with 1·95 million deaths (95% uncertainty interval 1·87–2·04) and has since decreased to 0·95 million deaths (0·91–1·01) in 2017. New cases of HIV globally peaked in 1999 (3·16 million, 2·79–3·67) and since then have gradually decreased to 1·94 million (1·63–2·29) in 2017. These trends, along with ART scale-up, have globally resulted in increased prevalence, with 36·8 million (34·8–39·2) people living with HIV in 2017. Prevalence of HIV was highest in southern sub-Saharan Africa in 2017, and countries in the region had ART coverage ranging from 65·7% in Lesotho to 85·7% in eSwatini. Our forecasts showed that 54 countries will meet the UNAIDS target of 81% ART coverage by 2020 and 12 countries are on track to meet 90% ART coverage by 2030. Forecasted results estimate that few countries will meet the UNAIDS 2020 and 2030 mortality and incidence targets. Interpretation Despite progress in reducing HIV-related mortality over the past decade, slow decreases in incidence, combined with the current context of stagnated funding for related interventions, mean that many countries are not on track to reach the 2020 and 2030 global targets for reduction in incidence and mortality. With a growing population of people living with HIV, it will continue to be a major threat to public health for years to come. The pace of progress needs to be hastened by continuing to expand access to ART and increasing investments in proven HIV prevention initiatives that can be scaled up to have population-level impact

    Estimating global injuries morbidity and mortality: methods and data used in the Global Burden of Disease 2017 study

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    BACKGROUND: While there is a long history of measuring death and disability from injuries, modern research methods must account for the wide spectrum of disability that can occur in an injury, and must provide estimates with sufficient demographic, geographical and temporal detail to be useful for policy makers. The Global Burden of Disease (GBD) 2017 study used methods to provide highly detailed estimates of global injury burden that meet these criteria. METHODS: In this study, we report and discuss the methods used in GBD 2017 for injury morbidity and mortality burden estimation. In summary, these methods included estimating cause-specific mortality for every cause of injury, and then estimating incidence for every cause of injury. Non-fatal disability for each cause is then calculated based on the probabilities of suffering from different types of bodily injury experienced. RESULTS: GBD 2017 produced morbidity and mortality estimates for 38 causes of injury. Estimates were produced in terms of incidence, prevalence, years lived with disability, cause-specific mortality, years of life lost and disability-adjusted life-years for a 28-year period for 22 age groups, 195 countries and both sexes. CONCLUSIONS: GBD 2017 demonstrated a complex and sophisticated series of analytical steps using the largest known database of morbidity and mortality data on injuries. GBD 2017 results should be used to help inform injury prevention policy making and resource allocation. We also identify important avenues for improving injury burden estimation in the future

    Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950-2019 : a comprehensive demographic analysis for the Global Burden of Disease Study 2019

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    Background Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019. Methods 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10-14 and 50-54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings The global TFR decreased from 2.72 (95% uncertainty interval [UI] 2.66-2.79) in 2000 to 2.31 (2.17-2.46) in 2019. Global annual livebirths increased from 134.5 million (131.5-137.8) in 2000 to a peak of 139.6 million (133.0-146.9) in 2016. Global livebirths then declined to 135.3 million (127.2-144.1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2.1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27.1% (95% UI 26.4-27.8) of global livebirths. Global life expectancy at birth increased from 67.2 years (95% UI 66.8-67.6) in 2000 to 73.5 years (72.8-74.3) in 2019. The total number of deaths increased from 50.7 million (49.5-51.9) in 2000 to 56.5 million (53.7-59.2) in 2019. Under-5 deaths declined from 9.6 million (9.1-10.3) in 2000 to 5.0 million (4.3-6.0) in 2019. Global population increased by 25.7%, from 6.2 billion (6.0-6.3) in 2000 to 7.7 billion (7.5-8.0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58.6 years (56.1-60.8) in 2000 to 63.5 years (60.8-66.1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019. Interpretation Over the past 20 years, fertility rates have been dropping steadily and life expectancy has been increasing, with few exceptions. Much of this change follows historical patterns linking social and economic determinants, such as those captured by the GBD Socio-demographic Index, with demographic outcomes. More recently, several countries have experienced a combination of low fertility and stagnating improvement in mortality rates, pushing more populations into the late stages of the demographic transition. Tracking demographic change and the emergence of new patterns will be essential for global health monitoring. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd.Peer reviewe

    Global burden of 369 diseases and injuries in 204 countries and territories, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019

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    Five insights from the Global Burden of Disease Study 2019

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    The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a rules-based synthesis of the available evidence on levels and trends in health outcomes, a diverse set of risk factors, and health system responses. GBD 2019 covered 204 countries and territories, as well as first administrative level disaggregations for 22 countries, from 1990 to 2019. Because GBD is highly standardised and comprehensive, spanning both fatal and non-fatal outcomes, and uses a mutually exclusive and collectively exhaustive list of hierarchical disease and injury causes, the study provides a powerful basis for detailed and broad insights on global health trends and emerging challenges. GBD 2019 incorporates data from 281 586 sources and provides more than 3.5 billion estimates of health outcome and health system measures of interest for global, national, and subnational policy dialogue. All GBD estimates are publicly available and adhere to the Guidelines on Accurate and Transparent Health Estimate Reporting. From this vast amount of information, five key insights that are important for health, social, and economic development strategies have been distilled. These insights are subject to the many limitations outlined in each of the component GBD capstone papers.Peer reviewe

    Morbidity and mortality after anaesthesia in early life: results of the European prospective multicentre observational study, neonate and children audit of anaesthesia practice in Europe (NECTARINE)

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    BACKGROUND: Neonates and infants requiring anaesthesia are at risk of physiological instability and complications, but triggers for peri-anaesthetic interventions and associations with subsequent outcome are unknown. METHODS: This prospective, observational study recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. The primary aim was to identify thresholds of pre-determined physiological variables that triggered a medical intervention. The secondary aims were to evaluate morbidities, mortality at 30 and 90 days, or both, and associations with critical events. RESULTS: Infants (n=5609) born at mean (standard deviation [sd]) 36.2 (4.4) weeks postmenstrual age (35.7% preterm) underwent 6542 procedures within 63 (48) days of birth. Critical event(s) requiring intervention occurred in 35.2% of cases, mainly hypotension (>30% decrease in blood pressure) or reduced oxygenation (SpO2 <85%). Postmenstrual age influenced the incidence and thresholds for intervention. Risk of critical events was increased by prior neonatal medical conditions, congenital anomalies, or both (relative risk [RR]=1.16; 95% confidence interval [CI], 1.04–1.28) and in those requiring preoperative intensive support (RR=1.27; 95% CI, 1.15–1.41). Additional complications occurred in 16.3% of patients by 30 days, and overall 90-day mortality was 3.2% (95% CI, 2.7–3.7%). Co-occurrence of intraoperative hypotension, hypoxaemia, and anaemia was associated with increased risk of morbidity (RR=3.56; 95% CI, 1.64–7.71) and mortality (RR=19.80; 95% CI, 5.87–66.7). CONCLUSIONS: Variability in physiological thresholds that triggered an intervention, and the impact of poor tissue oxygenation on patient's outcome, highlight the need for more standardised perioperative management guidelines for neonates and infants
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