European Space Agency experiments on thermodiffusion of fluid mixtures in space.

This paper describes the European Space Agency (ESA) experiments devoted to study thermodiffusion of fluid mixtures in microgravity environment, where sedimentation and convection do not affect the mass flow induced by the Soret effect. First, the experiments performed on binary mixtures in the IVIDIL and GRADFLEX experiments are described. Then, further experiments on ternary mixtures and complex fluids performed in DCMIX and planned to be performed in the context of the NEUF-DIX project are presented. Finally, multi-component mixtures studied in the SCCO project are detailed.

Assessing and improving data quality from community health workers: a successful intervention in Neno, Malawi.

SETTING: A community health worker (CHW) program was established in Neno District, Malawi, in 2007 by Partners In Health in support of Ministry of Health activities. Routinely generated CHW data provide critical information for program monitoring and evaluation. Informal assessments of the CHW reports indicated poor quality, limiting the usefulness of the data. OBJECTIVES: 1) To establish the quality of aggregated measures contained in CHW reports; 2) to develop interventions to address poor data quality; and 3) to evaluate changes in data quality following the intervention. DESIGN: We developed a lot quality assurance sampling-based data quality assessment tool to identify sites with high or low reporting quality. Following the first assessment, we identified challenges and best practices and followed the interventions with two subsequent assessments. RESULTS: At baseline, four of five areas were classified as low data quality. After 8 months, all five areas had achieved high data quality, and the reports generated from our electronic database became consistent and plausible. CONCLUSION: Program changes included improving the usability of the reporting forms, shifting aggregation responsibility to designated assistants and providing aggregation support tools. Local quality assessments and targeted interventions resulted in immediate improvements in data quality.

Acrylonitrile-sodium methallylsulfonate copolymer. DSC approach to membrane porosity of foam and hollow fibers.

The porosity of membranes formed from acrylonitrile-sodium methallylsulfonate copolymer was characterized from the analysis of the depression of the melting point of absorbed water. Membranes were obtained either as a foam or as a hollow fiber; the foam consisted of interconnected macrocavities (mean diameter about equal to 1 mm) while the hollow fiber was a symmetric membrane used for blood ultrafiltration. Differential scanning calorimetry (DSC) of water revealed both the Gaussian distribution of pore sizes and correspondingly, their mean size: 5.2 nm for the pores through the walls separating macrocavities in the foam and 5.6 and 10.6 nm associated with two distributions representing nearly equal amounts of absorbed water, for the hollow fiber. In addition to DSC, the water magnetic relaxation showed that the isothermal dehydration of the foam was due to the deswelling of macrocavities while the increasing amount of absorbed water in pores reflects its strong interaction with the polymer.

Diphenylamine-2-carboxylate blocks Cl(-)-HCO3- exchange in Necturus gallbladder epithelium.

Intracellular microelectrode techniques were employed to study the effects of diphenylamine-2-carboxylate (DPC) on ion transport in Necturus gallbladder epithelium. Under control conditions, addition of DPC to the mucosal bathing solution caused a concentration-dependent, reversible hyperpolarization of both cell membranes with no measurable resistance changes. In addition, DPC caused the following effects, all consistent with inhibition of apical membrane Cl(-)-HCO3- exchange: fall in intracellular Cl- activity (aCli), increase in intracellular pH (pHi), reduction of the changes in aCli and pHi produced by lowering mucosal solution [Cl-], and reduction of the change in pHi produced by lowering mucosal solution [HCO3-]. Similar studies in theophylline-treated preparations indicate that DPC also inhibits anion exchange under these conditions, but has no effect on the apical membrane electrodiffusive Cl- permeability induced by cyclic AMP. Under these conditions, DPC caused cell membrane hyperpolarization but had no effect on the apparent ratio of membrane resistances. In addition, DPC had no effects on the rapid changes in apical membrane voltage elicited by altering mucosal [Cl-], but caused significant reductions of the slower, secondary voltage changes observed in response to changes in mucosal [Cl-], and the changes in aCli and pHi produced by lowering mucosal [Cl-]. Because others have demonstrated that DPC blocks Cl- channels in other epithelia (Distefano, A., M. Wittner, E. Schlatter, H. J. Lang, H. Englert, and R. Greger. Diphenylamine-2-carboxylate, a blocker of the Cl(-)-conductive pathway in Cl(-)-transporting epithelia. Pfluegers++ Arch. 405: S95-S100, 1985), it is possible that the structures of those channels and that induced by cyclic AMP in Necturus gallbladder are different. Because of its relatively high affinity and rapid reversibility, DPC may become useful in studies of anion exchange in other cells.

[Effect of various blockers of nitrite and nitrogen oxide on the formation of nitrosamines]. / Influence de quelques bloquants du nitrite et de l'oxyde azotique sur la production de nitrosamines.

The effects of galacturonic, gallic, acetylneuraminic acid, ascorbate, cysteine, glutathion and imidazole on the formation of dimethylnitrosamine and diethylnitrosamine was studied in a simple aqueous medium with four different nitrite contents (50, 100, 500 and 1 000 ppm) and the two amines, compared with control samples. The nitrosamines were determined by the TELLING method (confirmed by photolysis). The results observed were compared with the laws of fixing nitrite in the form of nitrogen oxide, studied previously. For sarcosin and imidazole, the fixing takes into account the phenomena observed. The other substances lead to a conclusion that there are two stages in the process: 1) fixing of the nitrite to a greater or lesser degree in the form of a nitrogen oxide complex, 2) direct effect on the nitrosation reaction which is catalysed or slowed down. The discussion based on the literature, concludes that the final nitrosation reaction give rise to free radicals, even in an aqueous medium.

[Preservation of vitamin B1 and B2 during the preparation of pork meat]. / Devenir des vitamines B1 et B2 dans la fabrication des charcuteries.

Thiamin and riboflavin seem to resist fairly well to the proceedings of meat products studied here (cooked hams, patties, dry sausages). This result is normal enough to riboflavin, it is less for thiamin which sensitive to nitrite and to heating is well established by the literature. The origin of these observed phenomenons of protection is probably due to the complexation of these vitamins by the meat proteins. A similar phenomenon has been seen before by several authors on milk proteins, eggs and specially sulfhydril groups. This complexation is confirmed by the important release of both vitamins we noted during processing. They are determined much more easily on processed meat products than on raw materials. The nutritional repercussion of the observed phenomenon is difficult to estimate accurately. The vitamins release we find out, make them more available for the organism but it would be compared to the enzymatic decomplexation which occurs in vivo, during digestion, that we did not studied. Nevertheless such an approach would be necessary for the estimation of the practical value of the analytical determinations generally used.

[Structure of nitroso pigments in meats]. / Structures des pigments nitroso des viandes.

The study is concerned with the nitrosopigments formed during curing time. It concludes that a reductant nitrosohaem is formed, with a breakdown of the bond between haem and histidine, and it gives the accurate sequence of the reactions. This study has been conducted by measurement of the iron-dried material ratio, electrophoresis on acetonic extracts of pigments formed with ascorbate or cystein, measurement, during the photodecomposition of this extract, of photometric spectra, of ionised iron, and characterization of pyrroles functions.