2012-2014 sedimentation data for the Congaree River floodplain, SC, USA

This dataset contains sedimentation data that was collected for the Congaree River floodplain, SC, USA. The study sites were located at floodplain positions with varying flood frequencies and geomorphic positions. Flood frequency was determined using hydrological statistics based on data acquired from USGS gage #02169500 for the Congaree River; sites are classified as having high, intermediate, or low flood frequency. The geomorphic position classification was determined using field observations; sites are classified as abandoned channel, ridge, river margin, and swale positions. Sediment deposition was measured in centimeters and reflects the amount of sediment that was deposited on a feldspar clay pad that was installed at each of the sampling sites. The feldspar pads were installed in the summer of 2012 and cored and measured for deposition amounts in the summer of 2014. In the summer of 2012, soil samples were collected at each of the sampling sites. Each soil sample was analyzed for soil texture (percent sand, silt, and clay), major and micro-nutrients (parts per million), percent organic matter, and pH.

Sistema de adquisición de datos compacto para medidas de extensiometría y posición

En este proyecto se trata el diseño y construcción de un sistema de adquisición de datos compacto y de bajo coste para medidas de extensiometría y posición. Dicho sistema irá embarcado en una bicicleta de montaña con el fin de medir determinados parámetros. Estos parámetros son a) Elongación de las suspensiones, b) Deformación en el cuadro. Para la medida de elongación de las suspensiones se diseña y construye un sensor casero de bajo coste basado en una transparencia y un par de diodos fotoemisor y fotorreceptor infrarrojos. Se imprime un gradiente y se emplean dos tubos coaxiales de PVC. La medida de extensiometría se realiza con galgas extensiométricas, puentes de Wheatstone y amplificador de instrumentación. Las muestras se digitalizan con el ADC del microcontrolador C8051F020 de la casa Silabs, que se usa en una placa de desarrollo, y se almacenan en una memoria flash serie. Se desarrolla un software para PC con LabView para poder recibir, procesar y visualizar las muestras obtenidas de los distintos canales con el fin de analizarlas. Se obtienen conclusiones de los resultados de pruebas básicas. ABSTRACT On this project, the design and construction of a compact, low cost, data adquisition system for strain and position measurements is dealt with. Such system will be embedded on a bicycle in order to measure certain parameters. These are a) Suspension elongation, b) Frame deformation. For suspension elongation measurements, a homemade, low cost sensor based on a photoemitter-photoreceiver diode couple and a transparent sheet is designed and built. A gradient is printed in the transparent sheet, and two coaxial PVC pipes are used. Strain measurements are carried out by means of a strain gage, Wheatstone bridges and an instrumentation amplifier. Samples are digitized with Silabs’ C8051F020’s ADC, which is used in a development board, and are stored in a serial flash memory. Software for PC on LabView is developed in order to receive, process and visualize the obtained samples from each channel in order to analyze them. Results are obtained from basic tests.

Extracellular HIV-1 virus protein R causes a large inward current and cell death in cultured hippocampal neurons: Implications for AIDS pathology

The small HIV-1 accessory protein Vpr (virus protein R) is a multifunctional protein that is present in the serum and cerebrospinal fluid of AIDS patients. We previously showed that Vpr can form cation-selective ion channels across planar lipid bilayers, introducing the possibility that, if incorporated into the membranes of living cells, Vpr might form ion channels and consequently perturb the maintained ionic gradient. In this study, we demonstrate, by a variety of approaches, that Vpr added extracellularly to intact cells does indeed form ion channels. We use confocal laser scanning microscopy to examine the subcellular localization of fluorescently labeled Vpr. Plasmalemma depolarization and damage are examined using the anionic potential-sensitive dye bis(1,3-dibutylbarbituric acid) trimethine oxonol and propidium iodide (PI), respectively, and the effect of Vpr on whole-cell current is demonstrated directly by using the patch-clamp technique. We show that recombinant purified extracellular Vpr associates with the plasmalemma of hippocampal neurons to cause a large inward cation current and depolarization of the plasmalemma, eventually resulting in cell death. Thus, we demonstrate a physiological action of extracellular Vpr and present its mechanistic basis. These findings may have important implications for neuropathologies in AIDS patients who possess significant amounts of Vpr in the cerebrospinal fluid.