Studies of reaction geometry in oxidation and reduction of the alkaline silver electrode

Reaction geometry in oxidation and reduction of alkaline silver electrod

Online reflective diaries - using technology to strengthen the learning experience

Internet based technologies have benefits for students and staff in terms of time and information sharing. Students at the University of Glasgow were required to engage in reflective writing, with tutor support, as part of their course assessment. We examine the benefits of this approach in fostering a deep, holistic approach to learning, student contribution to course development through this reflection, and the issues in support of these activities

Studies of reaction geometry in oxidation and reduction of the alkaline silver electrode

Two methods of surface area estimations of sintered silver electrodes have given roughness factors of 58 and 81. One method is based on constant current oxidation, the other is based on potentiostatic oxidation. Examination of both wire and sintered silver electrodes via scanning electron microscopy at various stages of oxidation have shown that important structural features are mounds of oxide. In potentiostatic oxidations these appear to form on sites instantaneously nucleated while in constant current oxidations progressive nucleation is indicated

Studies of reaction geometry in oxidation and reduction of the alkaline silver electrode Quarterly report

Reaction kinetics in oxidation and reduction of alkaline silver electrod

Detecting adaptive evolution in phylogenetic comparative analysis using the Ornstein-Uhlenbeck model

Phylogenetic comparative analysis is an approach to inferring evolutionary process from a combination of phylogenetic and phenotypic data. The last few years have seen increasingly sophisticated models employed in the evaluation of more and more detailed evolutionary hypotheses, including adaptive hypotheses with multiple selective optima and hypotheses with rate variation within and across lineages. The statistical performance of these sophisticated models has received relatively little systematic attention, however. We conducted an extensive simulation study to quantify the statistical properties of a class of models toward the simpler end of the spectrum that model phenotypic evolution using Ornstein-Uhlenbeck processes. We focused on identifying where, how, and why these methods break down so that users can apply them with greater understanding of their strengths and weaknesses. Our analysis identifies three key determinants of performance: a discriminability ratio, a signal-to-noise ratio, and the number of taxa sampled. Interestingly, we find that model-selection power can be high even in regions that were previously thought to be difficult, such as when tree size is small. On the other hand, we find that model parameters are in many circumstances difficult to estimate accurately, indicating a relative paucity of information in the data relative to these parameters. Nevertheless, we note that accurate model selection is often possible when parameters are only weakly identified. Our results have implications for more sophisticated methods inasmuch as the latter are generalizations of the case we study.Comment: 38 pages, in press at Systematic Biolog

Thermal Control Characteristics of a Diffuse Bladed, Specular Base Louver System Status Report, Jul. - Dec. 1967

Heat transfer, and thermal control characteristics of diffuse bladed louver system for spacecraf

Thermal control characteristics of a diffuse bladed specular base louver system Final report

Diffuse bladed specular base louver system for spacecraft temperature contro

ScotPID - a model of collaboration

ScotPID is a national personal development initiative in Scotland, with thirteen higher education institutions taking part in the development of case studies which enhance personal development planning for students. As a model of collaboration, ScotPID involves all stakeholders: each core project group is composed of an academic, IT support manager, careers service adviser and undergraduate student, with support from QAA Scotland. The case study is developed by the contribution of all of the members of the team. The strength of the ScotPID collaboration is the varied background of the team members. However, collaboration between the ScotPID teams should also be encouraged, to strengthen the inter-institutional approach further

Exploring Io's atmospheric composition with APEX: first measurement of 34SO2 and tentative detection of KCl

The composition of Io's tenuous atmosphere is poorly constrained. Only the major species SO2 and a handful of minor species have been positively identified, but a variety of other molecular species should be present, based on thermochemical equilibrium models of volcanic gas chemistry and the composition of Io's environment. This paper focuses on the spectral search for expected yet undetected molecular species (KCl, SiO, S2O) and isotopes (34SO2). We analyze a disk-averaged spectrum of a potentially line-rich spectral window around 345 GHz, obtained in 2010 at the APEX-12m antenna (Atacama Pathfinder EXperiment). Using different models assuming either extended atmospheric distributions or a purely volcanically-sustained atmosphere, we tentatively measure the KCl relative abundance with respect to SO2 and derive a range of 4x10^{-4}-8x10^{-3}. We do not detect SiO or S2O and present new upper limits on their abundances. We also present the first measurement of the 34S/32S isotopic ratio in gas phase on Io, which appears to be twice as high as the Earth and ISM reference values. Strong lines of SO2 and SO are also analyzed to check for longitudinal variations of column density and relative abundance. Our models show that, based on their predicted relative abundance with respect to SO2 in volcanic plumes, both the tentative KCl detection and SiO upper limit are compatible with a purely volcanic origin for these species.Comment: Accepted for publication in ApJ. 11 pages, 4 figure

β-cell dysfunctional ERAD/ubiquitin/proteasome system in type 2 diabetes mediated by islet amyloid polypeptide-induced UCH-L1 deficiency.

ObjectiveThe islet in type 2 diabetes is characterized by β-cell apoptosis, β-cell endoplasmic reticulum stress, and islet amyloid deposits derived from islet amyloid polypeptide (IAPP). Toxic oligomers of IAPP form intracellularly in β-cells in humans with type 2 diabetes, suggesting impaired clearance of misfolded proteins. In this study, we investigated whether human-IAPP (h-IAPP) disrupts the endoplasmic reticulum-associated degradation/ubiquitin/proteasome system.Research design and methodsWe used pancreatic tissue from humans with and without type 2 diabetes, isolated islets from h-IAPP transgenic rats, isolated human islets, and INS 832/13 cells transduced with adenoviruses expressing either h-IAPP or a comparable expression of rodent-IAPP. Immunofluorescence and Western blotting were used to detect polyubiquitinated proteins and ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1) protein levels. Proteasome activity was measured in isolated rat and human islets. UCH-L1 was knocked down by small-interfering RNA in INS 832/13 cells and apoptosis was evaluated.ResultsWe report accumulation of polyubiquinated proteins and UCH-L1 deficiency in β-cells of humans with type 2 diabetes. These findings were reproduced by expression of oligomeric h-IAPP but not soluble rat-IAPP. Downregulation of UCH-L1 expression and activity to reproduce that caused by h-IAPP in β-cells induced endoplasmic reticulum stress leading to apoptosis.ConclusionsOur results indicate that defective protein degradation in β-cells in type 2 diabetes can, at least in part, be attributed to misfolded h-IAPP leading to UCH-L1 deficiency, which in turn further compromises β-cell viability