Ekotoksikološko pomembni ciklični peptidi iz cianobakterijskega cveta (Planktothrix rubescens) - grožnja človeškemu in okoljskemu zdravju

Background. The information of the overall production of major cyanobacterial cyclic peptides in a water body is essential for risk assessment and for the prediction of future development of the bloom. A procedure that gives a reviewof both toxic and non-hepatotoxic hydrophilic cyclic peptide production is important to evaluate the ecological conditions in the water environment and to predict the release of dangerous toxic and tumour promoting substances.Methods. The cyclic peptides were identified on the basis of their retention times, characteristic spectra, molecular masses and biological activity. The non-hepatotoxic cyclic peptides were characterised by their inhibition of porcine pancreatic elastase, while cytotoxicity to mammalian cells was tested with the MTT test on B16 cell line. Conclusions. The method presented gives a rapid, simultaneous assessment, preliminary identification and estimation of bioactive cyclic peptides. The synthesis of non-hepatotoxic cyclic peptides can mediate the release various toxic and otherwise biologically active substances that induce systemic genotoxicity in mammals

Desarrollo de un sistema alternativo de medición distribuida: experiencia piloto en un horno solar híbrido

El objetivo del trabajo está dirigido al desarrollo de un sistema que en tiempo real, facilite la medición en varios puntos de sensado, y permita como experiencia piloto el análisis en forma experimental de pérdidas de calor de un Horno Solar Híbrido, mediante el seguimiento del comportamiento térmico en PC. La metodología considera el relevamiento de antecedentes, y creación del sistema piloto de mediciones en forma distribuida. Los resultados de las experiencias de campo, respecto a la instalación y operación del instrumental demostraron un comportamiento adecuado aún con temperaturas superiores a 105 °C. Finalmente, el sistema demuestra ser una herramienta útil para el investigador, al posibilitar la adopción de decisiones dirigidas a hacer eficiente la energía termosolar.The objective of this work is aimed at developing a system in real time, facilitates the measurement at several points of sensing, and allow a pilot in an experimental analysis of heat losses of a Hybrid Solar Oven by tracking thermal behavior of PC. The methodology considers the survey background, and establishment of pilot measurements in a distributed manner. The results of field experiences, regarding the installation and operation of the instrument showed appropriate behavior even at temperatures above 105 ° C. Finally, the system proves to be a useful tool for researchers, by enabling the adoption of decisions to make efficient solar thermal power.Fil: Buigues Nollens, Arturo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Mecánica Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Pogrebinsky Mazarico, Leonardo Ariel. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Mecánica Aplicada; Argentin

Diseño de materiales multimedia adecuados al contexto de aprendizaje

La red provee de innumerables recursos interactivos que el docente puede utilizar en el trabajo con sus alumnos. Los applets java representan un método tremendamente versátil para incluir contenido multimedia en las páginas web. Su gran ventaja respecto al resto de mecanismos radica en la posibilidad infinita de interacción con el usuario. Se propone un método sencillo para que cualquier profesor, con conocimientos informáticos mínimos pueda elaborar actividades didácticas virtuales, para que sus estudiantes las utilicen fuera de línea, aprovechando una de las características más sobresalientes de Internet, la interactividad. De este modo las actividades diseñadas por el docente se adaptarán perfectamente a la realidad de sus alumnos y a sus necesidades de enseñanza y aprendizaje. Además presentamos aquí una de las actividades que hemos diseñado aplicando este método.Red de Universidades con Carreras en Informática (RedUNCI

Diseño de materiales multimedia adecuados al contexto de aprendizaje

La red provee de innumerables recursos interactivos que el docente puede utilizar en el trabajo con sus alumnos. Los applets java representan un método tremendamente versátil para incluir contenido multimedia en las páginas web. Su gran ventaja respecto al resto de mecanismos radica en la posibilidad infinita de interacción con el usuario. Se propone un método sencillo para que cualquier profesor, con conocimientos informáticos mínimos pueda elaborar actividades didácticas virtuales, para que sus estudiantes las utilicen fuera de línea, aprovechando una de las características más sobresalientes de Internet, la interactividad. De este modo las actividades diseñadas por el docente se adaptarán perfectamente a la realidad de sus alumnos y a sus necesidades de enseñanza y aprendizaje. Además presentamos aquí una de las actividades que hemos diseñado aplicando este método.Red de Universidades con Carreras en Informática (RedUNCI

Exciton Condensation and Perfect Coulomb Drag

Coulomb drag is a process whereby the repulsive interactions between electrons in spatially separated conductors enable a current flowing in one of the conductors to induce a voltage drop in the other. If the second conductor is part of a closed circuit, a net current will flow in that circuit. The drag current is typically much smaller than the drive current owing to the heavy screening of the Coulomb interaction. There are, however, rare situations in which strong electronic correlations exist between the two conductors. For example, bilayer two-dimensional electron systems can support an exciton condensate consisting of electrons in one layer tightly bound to holes in the other. One thus expects "perfect" drag; a transport current of electrons driven through one layer is accompanied by an equal one of holes in the other. (The electrical currents are therefore opposite in sign.) Here we demonstrate just this effect, taking care to ensure that the electron-hole pairs dominate the transport and that tunneling of charge between the layers is negligible.Comment: 12 pages, 4 figure

Anomalous Coulomb Drag in Electron-Hole Bilayers

We report Coulomb drag measurements on GaAs-AlGaAs electron-hole bilayers. The two layers are separated by a 10 or 25 nm barrier. Below T approximate to 1 K we find two features that a Fermi-liquid picture cannot explain. First, the drag on the hole layer shows an upturn, which may be followed by a downturn. Second, the effect is either absent or much weaker in the electron layer, even though the measurements are within the linear response regime. Correlated phases have been anticipated in these, but surprisingly, the experimental results appear to contradict Onsager's reciprocity theorem

Intramolecular Modulation of Serine Protease Inhibitor Activity in a Marine Cyanobacterium with Antifeedant Properties

Extracts of the Floridian marine cyanobacterium Lyngbya cf. confervoides were found to deter feeding by reef fish and sea urchins (Diadema antillarum). This antifeedant activity may be a reflection of the secondary metabolite content, known to be comprised of many serine protease inhibitors. Further chemical and NMR spectroscopic investigation led us to isolate and structurally characterize a new serine protease inhibitor 1 that is formally derived from an intramolecular condensation of largamide D (2). The cyclization resulted in diminished activity, but to different extents against two serine proteases tested. This finding suggests that cyanobacteria can endogenously modulate the activity of their protease inhibitors

Outcomes of renal transplantation in patients with AL amyloidosis: an international collaboration through The International Kidney and Monoclonal Gammopathy Research Group

Effective systemic therapies suppress toxic light chain production leading to an increased proportion of patients with light chain (AL) amyloidosis who survive longer albeit with end-stage renal disease. There is a critical need to identify patients in this population who benefit from renal transplantation. This multicenter, observational study from five countries includes 237 patients with AL amyloidosis who underwent renal transplantation between 1987 and 2020. With a median follow-up of 8.5 years, the median overall survival from renal transplantation was 8.6 years and was significantly longer in patients with complete and very good partial hematologic responses (CR + VGPR) compared to less than VGPR (9 versus 6.8 years; HR: 1.5, P = 0.04 [95% CI: 1–2.1]) at renal transplantation. Median graft survival was 7.8 years and was better in the CR + VGPR group (8.3 vs 5.7 years, HR: 1.4, P = 0.05 [95% CI: 1–2]). The frequency and time to amyloid recurrence in the graft was also lower (16% vs 37%, p = 0.01) and longer (median time not achieved vs 10 years, p = 0.001) in the CR + VGPR group. Comparing CR vs. VGPR there was no difference in overall or graft survival. Although 69 patients (29%) experienced hematologic relapse, treatment effectively prevented graft loss in the majority (87%). Renal transplantation in selected AL amyloidosis patients is associated with extended overall and renal graft survival. Patients with hematologic CR or VGPR have the most favorable outcomes, and these patients should be considered for renal transplantation