AC impedance study of degradation of porous nickel battery electrodes

AC impedance spectra of porous nickel battery electrodes were recorded periodically during charge/discharge cycling in concentrated KOH solution at various temperatures. A transmission line model (TLM) was adopted to represent the impedance of the porous electrodes, and various model parameters were adjusted in a curve fitting routine to reproduce the experimental impedances. Degradation processes were deduced from changes in model parameters with electrode cycling time. In developing the TLM, impedance spectra of planar (nonporous) electrodes were used to represent the pore wall and backing plate interfacial impedances. These data were measured over a range of potentials and temperatures, and an equivalent circuit model was adopted to represent the planar electrode data. Cyclic voltammetry was used to study the characteristics of the oxygen evolution reaction on planar nickel electrodes during charging, since oxygen evolution can affect battery electrode charging efficiency and ultimately electrode cycle life if the overpotential for oxygen evolution is sufficiently low

Comparison of Planted Loblolly and Slash Pine Performance in Southeast Texas

The performance of young (less than 10 yr) loblolly (Pinus taeda L.) and slash (Pinus elliottii Engelm.) pine trees was compared on planted sites in southeast Texas. Performance was compared for: total tree height; tree diameter; heigh to live tree crown; tree volume index,; incidence of fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shira if. sp. fusiforme); crookedness of stems; and survival rates. For these young trees, slash pine tended to perform better in southeast Texas than loblolly pine in total tree height, tree diameter, stem size, height to first live branch and stem straightness. However, loblolly pine was less susceptible to fusiform rust than slash pine, and its mortality rate was lower than slash pine. However, based on the performance of these young plantations, a recommendation the preferred pine species to plant in southeast Texas might be premature. South. J. Appl. For. 17(1): 26-31

Characterizing Fusiform Rust Incidence and Distribution in East Texas

Three measurement cycles were completed on an extensive network of loblolly( Pinus taeda L.) pine and slash (Pinus elliottii Engelm.) pine plots in industrial plantations throughout East Texas in 1984, 1987, and 1990.Because the incidence of fusiform rust caused by Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme had been recorded at each measurement, it is possible to characterize the temporal and geographic distribution of fusiform rust among these industrial pine plantations in East Texas. Average rust incidence for each species by two year age classes is presented. For loblolly pine, there is no apparent change in overall average incidence between 1987 and 1990, whereas for slash pine, there is an apparent overall average decline of about 7-8 percentage points. For some slash pine age classes, the incidence decline is 20-30 percentage points. Loblolly and slash pine rust incidence maps depict the geographic distribution of rust infection by plantation age groups in East Texas. South. J. Appl. For. 18(1):29-3

Identification of Protein Palmitoylation Inhibitors from a Scaffold Ranking Library

The addition of palmitoyl moieties to proteins regulates their membrane targeting, subcellular localization, and stability. Dysregulation of the enzymes which catalyzed the palmitoyl addition and/or the substrates of these enzymes have been linked to cancer, cardiovascular, and neurological disorders, implying these enzymes and substrates are valid targets for pharmaceutical intervention. However, current chemical modulators of zDHHC PAT enzymes lack specificity and affinity, underscoring the need for screening campaigns to identify new specific, high affinity modulators. This report describes a mixture based screening approach to identify inhibitors of Erf2 activity. Erf2 is the Saccharomyces cerevisiae PAT responsible for catalyzing the palmitoylation of Ras2, an ortholog of the human Ras oncogene proteins. A chemical library developed by the Torrey Pines Institute for Molecular Studies consists of more than 30 million compounds designed around 68 molecular scaffolds that are systematically arranged into positional scanning and scaffold ranking formats. We have used this approach to identify and characterize several scaffold backbones and R-groups that reduce or eliminate the activity of Erf2 in vitro. Here, we present the analysis of one of the scaffold backbones, bis-cyclic piperazine. We identified compounds that inhibited Erf2 auto-palmitoylation activity using a fluorescence-based, coupled assay in a high throughput screening (HTS) format and validated the hits utilizing an orthogonal gel-based assay. Finally, we examined the effects of the compounds on cell growth in a yeast cell-based assay. Based on our results, we have identified specific, high affinity palmitoyl transferase inhibitors that will serve as a foundation for future compound design

Primary care physicians are under-testing for celiac disease in patients with iron deficiency anemia: Results of a national survey

BACKGROUND: Iron deficiency anemia (IDA) is a common extra-intestinal manifestation of celiac disease (CD). Little is known about the frequency with which primary care physicians (PCPs) test for CD in patients with IDA. We aimed to describe how PCPs approach testing for CD in asymptomatic patients with IDA. METHODS: We electronically distributed a survey to PCPs who are members of the American College of Physicians. Respondents were asked whether they would test for CD (serologic testing, refer for esophagogastroduodenoscopy [EGD], or refer to GI) in hypothetical patients with new IDA, including: (1) a young Caucasian man, (2) a premenopausal Caucasian woman, (3) an elderly Caucasian man, and (4) a young African American man. These scenarios were chosen to assess for differences in testing for CD based on age, gender, and race. Multivariable logistic regression was used to identify independent predictors of testing. RESULTS: Testing for CD varied significantly according to patient characteristics, with young Caucasian men being the most frequently tested (61% of respondents reporting they would perform serologic testing in this subgroup (p CONCLUSIONS: PCPs are under-testing for CD in patients with IDA, regardless of age, gender, race, or post-menopausal status. The majority of PCPs surveyed reported they do not strictly adhere to established guidelines regarding a confirmatory duodenal biopsy in a patient with positive serology for CD

Unified analysis of terminal-time control in classical and quantum systems

Many phenomena in physics, chemistry, and biology involve seeking an optimal control to maximize an objective for a classical or quantum system which is open and interacting with its environment. The complexity of finding an optimal control for maximizing an objective is strongly affected by the possible existence of sub-optimal maxima. Within a unified framework under specified conditions, control objectives for maximizing at a terminal time physical observables of open classical and quantum systems are shown to be inherently free of sub-optimal maxima. This attractive feature is of central importance for enabling the discovery of controls in a seamless fashion in a wide range of phenomena transcending the quantum and classical regimes.Comment: 10 page

Optimal fishery with coastal catch

In many spatial resource models, it is assumed that an agent is able to harvest the resource over the complete spatial domain. However, agents frequently only have access to a resource at particular locations at which a moving biomass, such as fish or game, may be caught or hunted. Here, we analyze an infinite time‐horizon optimal control problem with boundary harvesting and (systems of) parabolic partial differential equations as state dynamics. We formally derive the associated canonical system, consisting of a forward–backward diffusion system with boundary controls, and numerically compute the canonical steady states and the optimal time‐dependent paths, and their dependence on parameters. We start with some one‐species fishing models, and then extend the analysis to a predator–prey model of the Lotka–Volterra type. The models are rather generic, and our methods are quite general, and thus should be applicable to large classes of structurally similar bioeconomic problems with boundary controls. Recommedations for Resource Managers Just like ordinary differential equation‐constrained (optimal) control problems and distributed partial differential equation (PDE) constrained control problems, boundary control problems with PDE state dynamics may be formally treated by the Pontryagin's maximum principle or canonical system formalism (state and adjoint PDEs). These problems may have multiple (locally) optimal solutions; a first overview of suitable choices can be obtained by identifying canonical steady states. The computation of canonical paths toward some optimal steady state yields temporal information about the optimal harvesting, possibly including waiting time behavior for the stock to recover from a low‐stock initial state, and nonmonotonic (in time) harvesting efforts. Multispecies fishery models may lead to asymmetric effects; for instance, it may be optimal to capture a predator species to protect the prey, even for high costs and low market values of the predators

Social media and young people’s involvement in social work education

While service-user involvement in social work education generally is increasing, young people’s involvement has, to date, been limited, and as such their voice is missing. Social media potentially offers mechanisms for addressing this, widening young people’s participation. This article presents the findings of research, conducted in partnership with young people, exploring different types of social media currently available that may have the potential to be used in social work education to provide young people with a voice. Using methods developed from systematic review processes, the research set out to find, synthesise and collate these different resources. The findings suggest social media could provide an appropriate mechanism for enabling young people to share experiences relevant to social care. However, whilst some resources do exist, there are fewer than expected. A need is identified to develop new sustainable ways of enabling young people to have a voice. Current approaches were found to replicate barriers associated with service provision being compartmentalised, service led, and framed by eligibility criteria. Recommendations are made for a united response from social work education institutions supporting approaches that give ownership to young people themselves whilst promoting sustainability and continuity