Benchmark low-mass objects in Moving Groups

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.In order to compile a sample of ultracool dwarfs that will serve as benchmarks for testing theoretical formation and evolutionary models, we selected low-mass cool (>M7) objects that are potentially members of five known young Moving Groups in the solar neighbourhood. We have studied the kinematics of the sample, finding that 49 targets belong to the young disk area, from which 36 are kinematic member of one of the five moving groups under study. Some of the identified low-mass members have been spectroscopically characterised (T-eff, log g) and confirmed as young members through a detailed study of age indicators

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

Optimized enzymatic synthesis of C-terminal peptide amides using subtilisin A from Bacillus licheniformis

A mild and efficient method for the conversion of C-terminal esters of side-chain protected peptides into an amide function via enzyme-catalysed ammonolysis in organic media with low water content is described. Subtilisin A, the alkaline serine protease from Bacillus licheniformis, was used as biocatalyst and ammonium carbamate as source of ammonia. Response surface methodology (RSM) and central composite design were employed to estimate the effects of reaction parameters such as molar ratio of ammonia source to peptide methyl ester (2:1–10:1), composition of the solvent system (ButOH/DMF, % v/v, 70:30–95:5) and water concentration (0.2–0.8%) at different temperatures (30–50 °C) for the preparation of Z-Ala-Phe-NH2 starting from Z-Ala-Phe-OMe. Optimum reaction conditions for maximum amide yield and minimum secondary hydrolysis were determined from cross-section analysis: temperature 30 °C, solvent composition ButOH/DMF 82.5:17.5 (v/v) containing 0.2% water (v/v) and molar ratio of ammonia source to peptide methyl ester of 10:1. The maximum yield of Z-Ala-Phe-NH2 was 87% after 21 h for a quantitative substrate conversion. The method proved to be generally applicable for the synthesis of C-terminal amides of dipeptides with different terminal amino acids and sequence

Optimized enzymatic synthesis of C-terminal peptide amides using subtilisin A from Bacillus licheniformis

A mild and efficient method for the conversion of C-terminal esters of side-chain protected peptides into an amide function via enzyme-catalysed ammonolysis in organic media with low water content is described. Subtilisin A, the alkaline serine protease from Bacillus licheniformis, was used as biocatalyst and ammonium carbamate as source of ammonia. Response surface methodology (RSM) and central composite design were employed to estimate the effects of reaction parameters such as molar ratio of ammonia source to peptide methyl ester (2:1–10:1), composition of the solvent system (ButOH/DMF, % v/v, 70:30–95:5) and water concentration (0.2–0.8%) at different temperatures (30–50 °C) for the preparation of Z-Ala-Phe-NH2 starting from Z-Ala-Phe-OMe. Optimum reaction conditions for maximum amide yield and minimum secondary hydrolysis were determined from cross-section analysis: temperature 30 °C, solvent composition ButOH/DMF 82.5:17.5 (v/v) containing 0.2% water (v/v) and molar ratio of ammonia source to peptide methyl ester of 10:1. The maximum yield of Z-Ala-Phe-NH2 was 87% after 21 h for a quantitative substrate conversion. The method proved to be generally applicable for the synthesis of C-terminal amides of dipeptides with different terminal amino acids and sequence

Sol–gel immobilization of Alcalase from Bacillus licheniformis for application in the synthesis of C-terminal peptide amides

Alcalase 2.4L FG, a commercial preparation of Subtilisin A, was physically entrapped in glass sol–gel matrices using alkoxysilanes of different types mixed with tetramethoxysilane (TMOS). The materials were used for catalyzing C-terminal amidation of Z-Ala-Phe-OMe in a mixture of tert-butanol/DMF. From the screening of silane monomers in the sol–gel coating process, it was concluded that dimethyldimethoxysilane (DMDMOS) gave the best performance, and Alcalase immobilized therein exhibited the highest activity in the ammonolysis of Z-Ala-Phe-OMe. The percentage of protein immobilization was in the range of 68–98%, and total amidation activity of the immobilized Alcalase was up to 1.76 µmol/h/mg gel. We investigated the immobilization efficiency for a protein mass range of 2.8–9.7 mg per mmol total silanes, to determine the immobilization capacity of the biosilica support. The optimum enzyme loading capacity in the silica matrix was 115 mg/g dry silica xerogel (11.5%, w/w). The amount of the DMDMOS silicate was optimized by adjusting the molar ratio of silane mixture (DMDMOS and TMOS at 1:1). Biocatalyst sol–gel particles prepared at optimum immobilization conditions retained 100% of the original activity even after 14 cycles of repeated use. Reproducibility of the immobilization technique was also investigated by evaluating the catalytic efficiency of the obtained preparations. The thermal stability of the protease at 70 °C increased threefold upon entrapment in sol–gel materials, and twofold under storage for 50 days at ambient temperature

The effect of cooperative learning on the thinking skills development of Foundation Phase learners

We report on the findings obtained from a mixed-method study conducted in South Africa with a conveniently and purposively selected sample of 60 Grade 3 learners and their two teachers. The aim was to establish the thinking skills development of the learners and to determine the merits of a curriculum-based cooperative teaching and learning intervention programme for enhancing and/or improving the thinking skills of the learners. Quantitative data were collected by means of pre- and post-testing, as well as by means of structured observations during the fifteen-week implementation period of the intervention. Qualitative data were collected by means of semi-structured interviews with the teachers and focus group interviews with the learners. The research findings have significant implications for enhancing teaching practice in the Foundation Phase to improve thinking skills by means of a cooperative teaching and learning approach.http://dx.doi.org/10.1080/16823206.2013.84701