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.     

Cascaded production of biogas and hydrochar from wheat straw: Energetic potential and recovery of carbon and plant nutrients

The increasing interest in biogas production has brought notable attention to lignocellulosic wastes as a promising and yet unexploited feedstock. As these materials are usually highly recalcitrant the energetic efficiency of biogas production, however, is comparatively low. With the aim to overcome this drawback, a novel cascaded approach was investigated that combines anaerobic digestion with hydrothermal carbonization (HTC). The latter is used to convert the digestate into a carbon-rich product termed hydrochar. An energetic evaluation of this cascaded treatment shows that the energy recovery can be nearly doubled compared to single anaerobic digestion.Furthermore, systematic HTC experiments with both fresh and digested wheat straw and with reaction temperatures of 190 °C, 210 °C, 230 °C, and 250 °C revealed an effect of reaction temperature on carbon, nitrogen, and phosphorus concentration in the final hydrochar. Carbon, nitrogen and phosphorus are primarily retained in the hydrochar, which could favor its use as soil ameliorant instead of an energy carrier.     

Z-identification of charged particles by signal risetime in silicon surface barrier detectors

The risetimes of the signals collected from totally depleted silicon surface barrier detectors have been measured and show strong dependence on the Z of the incident charged particles. This dependence has been observed for incident ions ranging from tritons to fluorine. A simple theoretical model has been used to predict the observed risetimes for ions whose range is long compared to the diameter of the ionization column which they produce in silicon. For particles with ranges short compared to the depletion depth of the detector it is found that the Z-dependence can be enhanced by allowing these ions to enter through the rear face of the totally depleted detector. For hydrogen and helium ions the dependence of the risetime on the mass M of the ion is also observed.     

ALTAR: achieving learning through action research

This paper describes a collaborative action research (AR) study that took place between a U.K. university and a large U.K. manufacturing organisation, Britvic Soft Drinks Ltd. The ALTAR (Achieving Learning Through Action Research) project involved a number of AR cycles involving participants at different levels of the collaborating organisation. Britvic was already in the process of adopting knowledge management (KM) software but it was recognised that they could better exploit KM technologies by undertaking the AR project described in the paper. The project involved developing academic theory into practical concepts that influenced actions in the organisation and fed back into the academic research. The ALTAR approach and findings are described in this paper and conclusions are drawn about the AR study and its implications for AR, KM and for the future study of organisational learning through AR. The conclusions of the work are of practical use to managers in a variety of organisations and will inform academic research into cognate disciplines using the AR process.     

Molecular dynamics of stage 3 cesium intercalated graphite C36Cs

Stage 3 casium intercalated graphite is simulated. The dependence of the structural properties of the simulated system on the barrier height of the graphite periodic potential is shown. The periodic component of the radial distribution function g(r) due to the substrate modulation potential is clearly visible. It appears as a result of the delicate balance between the in-plane cesium-cesium interactions and the substrate modulation potential.     

Rethinking organisational size in IS research: meaning,measurement and redevelopment

While organisational size is a popular construct in information systems (IS) research, findings from its use have been inconsistent. Few studies have explored this inconsistency or attempted to address this problem. This paper uses Churchill's measure development paradigm to conduct three separate but related investigations into the size construct. Study 1 explored the domain and dimensions of size. Some 2000 research papers published in six leading IS journals over an 11-year period were read in order to determine what researchers thought size meant and how they measured it. The study found 21 constructs underpinning the size construct and 25 ways of measuring size, but no clear relationship between size meaning and measurement. Study 2 assessed the construct's content validity using a concept map exercise involving 41 participants. Multidimensional scaling clustered the constructs into three conceptual groups. Study 3 administered the size construct in a survey with a sample of 163 Australian firms. The study found that the data supported the constructs observed in Study 2 and that a group of eight constructs could be used to differentiate between smaller and larger firms in the sample. Analysis revealed that organisational levels, risk aversion, geographic distribution and employment reflected respondents’ self-nominated size.     

Extended stochastic resonance (SR) and its applications in weak mechanical signal processing

To catch symptoms of machine failure as early as possible, one of the most important strategies is to apply more progressive techniques during signal processing. This paper presents a method based on stochastic resonance (SR) to detect weak fault signal. First, a discrete model of a bistable system that can demonstrate SR is researched, and the stability condition for controlling the selection of model parameters of the discrete model and guarantee the solving convergence are established. Then, the frequency range of the weak signals that the SR model can detect is extended through a type of normalized scale transformation. Finally, the method is applied to extract the weak characteristic component from heavy noise to indicate the little crack fault in a bearing outer circle.     

Problems With Hydrological Monitoring: Case of the Australian Representative Basins Program

ABSRTACT

Hydrologic and geomorphological monitoring for the ambitious mega Australia-wide Representative Basins Program began with a shaky start. While a wider view of Australia's diverse water resource base was most imperative by the 60's the Program collapsed under the weight of data inadequacies along with administrative and political problems that only states, territories and federal governments can together generate. Since then state focused programs have continued to dominate environmental monitoring.