Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2–3 ‰ heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures

The comparative responsiveness of Hospital Universitario Princesa Index and other composite indices for assessing rheumatoid arthritis activity

Objective To evaluate the responsiveness in terms of correlation of the Hospital Universitario La Princesa Index (HUPI) comparatively to the traditional composite indices used to assess disease activity in rheumatoid arthritis (RA), and to compare the performance of HUPI-based response criteria with that of the EULAR response criteria. Methods Secondary data analysis from the following studies: ACT-RAY (clinical trial), PROAR (early RA cohort) and EMECAR (pre-biologic era long term RA cohort). Responsiveness was evaluated by: 1) comparing change from baseline (Delta) of HUPI with Delta in other scores by calculating correlation coefficients; 2) calculating standardised effect sizes. The accuracy of response by HUPI and by EULAR criteria was analyzed using linear regressions in which the dependent variable was change in global assessment by physician (Delta GDA-Phy). Results Delta HUPI correlation with change in all other indices ranged from 0.387 to 0.791); HUPI's standardized effect size was larger than those from the other indices in each database used. In ACT-RAY, depending on visit, between 65 and 80% of patients were equally classified by HUPI and EULAR response criteria. However, HUPI criteria were slightly more stringent, with higher percentage of patients classified as non-responder, especially at early visits. HUPI response criteria showed a slightly higher accuracy than EULAR response criteria when using Delta GDA-Phy as gold standard. Conclusion HUPI shows good responsiveness in terms of correlation in each studied scenario (clinical trial, early RA cohort, and established RA cohort). Response criteria by HUPI seem more stringent than EULAR''s

Diseño de reactores semi-batch.

Artículo que estudia el comportamiento de reactores semi-batch en que uno de los reactivos es alimentado a flujo constante sobre el otro, contenido en un reactor bien agitado

Errores en la aplicación del método diferencial a reactores operados a conversión finita.

Trabajo que considera el error introducido cuando se aplica el método diferencial para obtener la ecuación cinética utilizando datos de reactores operados a conversión finita.Aunque los resultados con aplicados a reactores tubulares con flujo pistón, se pueden extender fácilmente a sistemas batch

Activated translation signaling in placenta from pregnant women with gestational diabetes mellitus: possible role of leptin

Placentas from gestational diabetes (GDM) suff er from structural and functional changes including overgrowth. That is why we aimed to study [ 3 H]-leucine incorporation into protein in addition to translation signaling in placenta from GDM. Thus, we investigated the expression of leptin and leptin receptor (LEPR), as well as the activation state of signaling proteins regulating protein synthesis, such as mTOR, S6 Kinase, EIF4E-BP1, EIF4E, and eEF2 by measuring protein phosphorylation by immunoblot. [ 3 H]-Leucine incorporation into protein also was determined in trophoblastic placenta explants from GDM and control pregnancy. We found that leptin and LEPR expression are increased in placentas from GDM and the translation machinery activity as well as [ 3 H]-leucine incorporation into protein were higher in placentas from GDM compared with placentas from control pregnancy. In conclusion, protein synthesis rate is increased in placenta from GDM patients, and this may be due, at least in part, by the activation of translation signaling. The increased expression of leptin and LEPR may contribute to these eff ects. These results may provide a possible mechanism for the previously observed increase in placenta growth in GDM.Fil: Pérez Pérez, A.. Universidad de Sevilla; EspañaFil: Maymo, Julieta Lorena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Gambino, Yésica Paola. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Guadix, P.. Universidad de Sevilla; EspañaFil: Dueñas, J. L.. Universidad de Sevilla; EspañaFil: Varone, Cecilia Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Sánchez Margalet, V.. Universidad de Sevilla; Españ