Methanol Electro-Oxidation on Carbon-Supported PtRu Nanowires

One of the key objectives in fuel cell technology is to improve the alcohol oxidation efficiency of Pt-based catalysts. A series of carbon-supported PtRu nanowires with different concentrations of Pt and Ru were prepared for application in methanol oxidation in acid media. The physicochemical properties and electrocatalytic activity of these catalysts during methanol oxidation are function on their structure, morphology and composition. A Pt60Ru40/C catalyst shows the best behaviour towards methanol electro-oxidation allowing decrease the onset potential approximately 0.2 V respect to others PtRu/C synthesised nanowires. The structural modification of Pt by Ru and synergetic character of RuPt are main factors that could contribute to reduction of energy necessary for electro-oxidation process. The Pt and PtRu nanowires have different sizes and distribution on the substrate. The average crystallite sizes, found by XRD, are in the 4.6–5.9 nm range and the lattice parameter is between 0.3903–0.3908 nm. Small differences with the values of the Pt/C catalyst were found. The XPS results show a prevailing presence of metallic Pt and Ru4+ species.The authors thank to CNPq (grants: 304419/2015-0, 402243/2012-9, 400443/2013-9, 407274/2013-8 and 310282/2013-6), CAPES and FAPITEC for the scholarships and financial support

Yam tuber and maize grain yield response to cropping system intensification in south-west Nigeria

Open Access Article; Published online: 11 Dec 2017Four factorial trials were conducted with yam (Dioscorea rotundata Poir.) at Ibadan, Nigeria from 2013 to 2015, investigating effects of (1) tillage (2) fertilizer (3) intercropping (4) yam plant densities. Yam tuber yields varied between years (2013: 16.44 Mg ha−1; 2014: 10.08 Mg ha−1; 2015 26.61 Mg ha−1). In 2013 neither tillage nor fertilizer affected tuber yields. In 2014 tillage increased yields (+25.4%, P < 0.0001), fertilizer reduced yield (−10.5%; P = 0.0046). In 2015 tillage increased tuber yields by 8.1% (ns), fertilizer application increased yield (+17.5%, P = 0.0017). Across the years, tuber yields increased (P < 0.01) with increasing yam density with a constant increase in 2013 up to the highest density, yet yields leveled out above 14,815 plants ha−1 in 2014 and 2015. Intercropping with maize (66,667 plants ha−1) reduced tuber yield by 42.62% in 2013, 44.52% in 2014 and 30.68% in 2015 (P < 0.01 all years) across all yam densities. Maize grain yield was higher in sole crop in 2 years. Fertilizer increased yields in all years (P < 0.0001). Maize yield had no response to the yam densities. Ridging had a negative effect on grain yield in 2015 (−0.3 Mg ha−1, P = 0.0002). Increasing plant density appears a safe measure to increase yam yields

Sustained high serum caspase-3 concentrations and mortality in septic patients

Caspase-3 is the main executor of the apoptotic process. Higher serum caspase-3 concentrations in non-survivor compared to survivor septic patients have been found. The objectives of this work (with the increase of sample size to 308 patients, and the determination of serum caspase-3 concentrations also on days 4 and 8 of diagnosis of severe sepsis) were to know whether an association between serum caspase-3 concentrationss during the first week, degree of apoptosis, sepsis severity, and sepsis mortality exists. We collected serum samples of 308 patients with severe sepsis from eight intensive care units on days 1, 4 and 8 to measure concentrations of caspase-3 and caspase-cleaved cytokeratin (CCCK)-18 (to assess degree of apoptosis). End point was 30-day mortality. We found higher serum concentrations of caspase-3 and CCCK-18 in non-survivors compared to survivors on days 1 (p < 0.001), 4 (p < 0.001), and 8 (p < 0.001). We found an association between serum caspase-3 concentrations on days 1, 4 and 8 of severe sepsis diagnosis and serum CCCK-18 concentrations (p < 0.001), SOFA (p < 0.001), serum acid lactic concentrations (p < 0.001), and 30-day sepsis mortality (p < 0.001). The new findings of this work were that an association between serum caspase-3 concentrations during the first week, apoptosis degree, sepsis severity, and sepsis mortality exists

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Global, regional, and national age-sex-specific mortality and life expectancy, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

BACKGROUND: Assessments of age-specific mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Affairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. METHODS: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specific mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in different components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. FINDINGS: Globally, 18·7% (95% uncertainty interval 18·4–19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2–59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5–49·6) to 70·5 years (70·1–70·8) for men and from 52·9 years (51·7–54·0) to 75·6 years (75·3–75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5–51·7) for men in the Central African Republic to 87·6 years (86·9–88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3–238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6–42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2–5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. INTERPRETATION: This analysis of age-sex-specific mortality shows that there are remarkably complex patterns in population mortality across countries. The findings of this study highlight global successes, such as the large decline in under-5 mortality, which reflects significant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing

Model selection changes the spatial heterogeneity and total potential carbon in a tropical dry forest

Understanding how aboveground biomass (AGB) is spatially distributed in the landscape and what factors are involved is critical to identify the ecological constraints limiting the magnitude and the allocation of carbon (C) stocks. Yet these factors remain poorly quantified for much of the world. The aim of this study is to identify the factors that influence the reconstruction of potential AGB and its spatial heterogeneity under current climate. A range of statistical approaches is used here to reconstruct the spatial distribution of AGB found in a tropical dry forest in Mexico. This is one of the first studies to directly quantify the predictive performance of various techniques within a common framework applied to AGB estimates from field observations and biophysical variables. The results suggest that general linear model (GLM) and the general additive model (GAM) performed similarly and outperformed other more complex approaches, such as automated neural networks, generalized linear mixed models via penalized quasi-likelihood, MaxEnt and random forest. GLM and GAM approaches also showed good performance in comparison to independent field observations over different spatial resolutions. MaxEnt performed poorly against independent validation data. The GLM, GAM, neural networks and regression tree models returned comparable mean AGB, suggesting that the potential AGB in the studied area is ∼132 Mg ha−1. The biomass spatial distribution is represented differently by the different models. Neural networks and regression tree approaches tend to cluster similar AGB estimates with a large range of the spatial autocorrelation, while the GLM is capable of reproducing the spatial distribution of the biomass