The Oxidation State of Sulfur in Lunar Apatite

Lunar apatites contain hundreds to thousands of parts per million of sulfur. This is puzzling because lunar basalts are thought to form in low oxygen fugacity (f(sub O2)) conditions where sulfur can only exist in its reduced form (S2()), a substitution not previously observed in natural apatite. We present measurements of the oxidation state of S in lunar apatites and associated mesostasis glass that show that lunar apatites and glass contain dominantly S2(), whereas natural apatites from Earth are only known to contain S6+. It is likely that many terrestrial and martian igneous rocks contain apatites with mixed sulfur oxidation states. The S6(+)/S2() ratios of such apatites could be used to quantify the f(sub O2) values at which they crystallized, given information on the portioning of S6(+) and S2() between apatite and melt and on the S6(+)/S2() ratios of melts as functions of f(sub O2) and melt composition. Such a well-calibrated oxybarometer based on this the oxidation state of S in apatite would have wide application

Examination of Maskelynite through Static Recompression and Dynamic Compression

This is an experimental study that aims to clarify the possible formation mechanisms of maskelynite. Maskelynite is a diaplectic glass, that forms during shock compression of feldspar far below the melting point, and without fusion. Maskelynite also paramorphises precursor feldspar grains. Maskelynite is an important probe of shock-pressures at terrestrial impact sites and in many meteorites. Two mechanisms of formation of maskelynite are examined here: 1) maskelynite is result of a pressure-induced amorphization of feldspar compressed beyond its mechanical stability where the formation of thermodynamically stable phases is kinetically inhibited [1, 2]. 2) Feldspar transforms upon dynamic compression into a high-pressure polymorph. Upon release from the peak shock pressure, this crystalline polymorph transforms back either into a dense glass or a highly disordered solid that appears amorphous in common probes (optical microscope, optical spectroscopy, diffraction). The latter scenario avails for diaplectic silica that formed in shock-experiments on quartz. Upon static compression of synthetic diaplectic silica at 300 K the material resumes the crystalline structure of stishovite [3], a high-pressure polymorph of silica which has also been observed in situ during shock compression of fused quartz [4]. Hence, the second scenario implies a memory effect of the high-pressure crystalline structure in the diaplectic glass. In the present study, we test this hypothesis for maskelynite by a) X-ray diffraction of maskelynite similar to the study of diaplectic silica in [3], b) synchrotron X-ray diffraction analysis of synthetic maskelynite at ambient pressure, both with the goal of identifying possible crystalline states. If no crystalline state is observed, the second proposed mechanism of maskelynite formation is not supported and the first mechanism appears more likely. In the static compression experiment I find indications of a change in middle-range order of maskelynite but no transition to long-range crystalline order upon compression to 19 GPa. In the shock-recovered maskelynite I observe crystalline material, even in material recovered from 38.5 GPa. The crystalline material is disseminated in an amorphous matrix and has feldspar-like structure rather than a structure related to a high-pressure polymorph of feldspar. Hence this crystalline material is remnant crystalline feldspar rather than a phase that formed upon shock-compression

4,6-Bis(diphenyl­phosphan­yl)dibenzo[b,d]furan

The asymmetric unit of the title compound, C36H26OP2, comprises two mol­ecules which have slightly different conformations of the phenyl ring substituents. In both mol­ecules, the dibenzofuran unit is close to being planar, with dihedral angles of 3.20 (3) and 1.86 (2)° for the two mol­ecules. Its planarity affects the intra­molecular distances between P atoms, with P⋯P distances of 5.574 (2) and 5.485 (2) Å for the two mol­ecules

New Tetromycin Derivatives with Anti-Trypanosomal and Protease Inhibitory Activities †

Four new tetromycin derivatives, tetromycins 1–4 and a previously known one, tetromycin B (5) were isolated from Streptomyces axinellae Pol001T cultivated from the Mediterranean sponge Axinella polypoides. Structures were assigned using extensive 1D and 2D NMR spectroscopy as well as HRESIMS analysis. The compounds were tested for antiparasitic activities against Leishmania major and Trypanosoma brucei, and for protease inhibition against several cysteine proteases such as falcipain, rhodesain, cathepsin L, cathepsin B, and viral proteases SARS-CoV Mpro, and PLpro. The compounds showed antiparasitic activities against T. brucei and time-dependent inhibition of cathepsin L-like proteases with Ki values in the low micromolar range

A Model for Improving the Health and Quality of Life of Single Mothers in the Developing World

Among the impoverished population of coastal Kenya, there is a rapidly growing group of young single mothers who suffer from adverse health outcomes, incomplete schooling, social ostracism by their communities, and economic hardship. To address this problem, in 2008 the Single Mothers Program (SMP) selected a group of vulnerable single mothers, provided them with basic relief and education, equipped them with training and start-up capital to run their own businesses, and assessed the impact of the program via a pre- and post-implementation survey. After two years in the program, a majority of the single mothers increased their contraceptive use, increased their degree of literacy, increased their individual incomes, and were more positively perceived by their communities. This study demonstrates a program model that can be used to improve the health and quality of life of single mothers and their children in similar communities throughout the world. Keywords: single mothers, Kenya, quality of life, women’s health, microfinance, AfricaAfr J Reprod Health 2013; 17[4]: 14-2

A Model for Improving the Health and Quality of Life of Single Mothers in the Developing World

Among the impoverished population of coastal Kenya, there is a rapidly growing group of young single mothers who suffer from adverse health outcomes, incomplete schooling, social ostracism by their communities, and economic hardship. To address this problem, in 2008 the Single Mothers Program (SMP) selected a group of vulnerable single mothers, provided them with basic relief and education, equipped them with training and start-up capital to run their own businesses, and assessed the impact of the program via a pre- and post-implementation survey. After two years in the program, a majority of the single mothers increased their contraceptive use, increased their degree of literacy, increased their individual incomes, and were more positively perceived by their communities. This study demonstrates a program model that can be used to improve the health and quality of life of single mothers and their children in similar communities throughout the world.Parmi la population pauvre de la côte du Kenya, il y a un groupe en pleine croissance des jeunes mères célibataires qui souffrent de conséquences nocives sur la santé, la scolarisation abandonnée, l'ostracisme social par leurs communautés, et des difficultés économiques. Pour résoudre ce problème, en 2008, le Programme des Mères Célibataires (PMC) a sélectionné un groupe de mères célibataires vulnérables, leur a fourni des secours et de l'éducation de base, leur a donné une formation et le capital initial pour leur permettre de fonctionner leurs propres entreprises et d'évaluer l'impact du programme à travers une enquête pré- et post- exécution. Après deux ans dans le programme, la majorité des mères célibataires ont augmenté leur utilisation de la contraception, ont augmenté leur niveau d’alphabétisation, de leurs revenus individuels et ont perçu plus positivement par leurs communautés. Cette étude démontre un modèle de programme qui peut être utilisé pour améliorer la santé et la qualité de vie des mères célibataires et de leurs enfants dans les communautés pareilles à travers le monde

The oxidation state of sulfur in lunar apatite

Lunar apatites contain hundreds to thousands of parts per million of sulfur. This is puzzling because lunar basalts are thought to form in low oxygen fugacity (f_(O_2)) conditions where sulfur can only exist in its reduced form (S^(2–)), a substitution not previously observed in natural apatite. We present measurements of the oxidation state of S in lunar apatites and associated mesostasis glass that show that lunar apatites and glass contain dominantly S^(2–), whereas natural apatites from Earth are only known to contain S^(6+). It is likely that many terrestrial and martian igneous rocks contain apatites with mixed sulfur oxidation states. The S^(6+)/S^(2–) ratios of such apatites could be used to quantify the f_(O_2) values at which they crystallized, given information on the portioning of S^(6+) and S^(2–) between apatite and melt and on the S^(6+)/S^(2–) ratios of melts as functions of f_(O_2) and melt composition. Such a well-calibrated oxybarometer based on this the oxidation state of S in apatite would have wide application

The oxidation state of sulfur in lunar apatite

Lunar apatites contain hundreds to thousands of parts per million of sulfur. This is puzzling because lunar basalts are thought to form in low oxygen fugacity (f_(O_2)) conditions where sulfur can only exist in its reduced form (S^(2–)), a substitution not previously observed in natural apatite. We present measurements of the oxidation state of S in lunar apatites and associated mesostasis glass that show that lunar apatites and glass contain dominantly S^(2–), whereas natural apatites from Earth are only known to contain S^(6+). It is likely that many terrestrial and martian igneous rocks contain apatites with mixed sulfur oxidation states. The S^(6+)/S^(2–) ratios of such apatites could be used to quantify the f_(O_2) values at which they crystallized, given information on the portioning of S^(6+) and S^(2–) between apatite and melt and on the S^(6+)/S^(2–) ratios of melts as functions of f_(O_2) and melt composition. Such a well-calibrated oxybarometer based on this the oxidation state of S in apatite would have wide application

Fractionated marine invertebrate extract libraries for drug discovery

The high-throughput screening and drug discovery paradigm has necessitated a change in preparation of natural product samples for screening programs. In an attempt to improve the quality of marine natural products samples for screening, several fractionation strategies were investigated. The final method used HP20SS as a solid support to effectively desalt extracts and fractionate the organic components. Additionally, methods to integrate an automated LCMS fractionation approach to shorten discovery time lines have been implemented