Competitive partitioning of rotational energy in gas ensemble equilibration

A wide-ranging computational study of equilibration in binary mixtures of diatomic gases reveals the existence of competition between the constituent species for the orbital angular momentum and energy available on collision with the bath gas. The ensembles consist of a bath gas AB(v;j), and a highly excited minor component CD(v';j'), present in the ratio AB:CD = 10:1. Each ensemble contains 8000 molecules. Rotational temperatures (T(r)) are found to differ widely at equilibration with T(r)(AB)/T(r)(CD) varying from 2.74 to 0.92, indicating unequal partitioning of rotational energy and angular momentum between the two species. Unusually, low values of T(r) are found generally to be associated with diatomics of low reduced mass. To test effects of the equi-partition theorem on low T(r) we undertook calculations on HF(6;4) in N(2)(0;10) over the range 100-2000 K. No significant change in T(r)(N2)/T(r)(HF) was found. Two potential sources of rotational inequality are examined in detail. The first is possible asymmetry of -Δj and +Δj probabilities for molecules in mid- to high j states resulting from the quadratic dependence of rotational energy on j. The second is the efficiency of conversion of orbital angular momentum, generated on collision with bath gas molecules, into molecular rotation. Comparison of these two possible effects with computed T(r)(AB)/T(r)(CD) shows the efficiency factor to be an excellent predictor of partitioning between the two species. Our finding that T(r) values for molecules such as HF and OH are considerably lower than other modal temperatures suggests that the determination of gas ensemble temperatures from Boltzmann fits to rotational distributions of diatomics of low reduced mass may require a degree of caution

Enhancing quality of life in older adults: A comparison of muscular strength and power training

<p>Abstract</p> <p>Background</p> <p>Although progressive resistance strength training (ST) has been found to improve various measures of physical functioning in older adults, the benefit to quality of life is unclear. Additionally, recent evidence suggests that high velocity power training (PT) may be more beneficial for physical functioning than ST, but it is not known whether this type of training impacts quality of life. The purpose of this study was to compare changes in multiple measures of quality of life resulting from ST vs. PT in older adults. A no exercise group was also included as control comparison condition.</p> <p>Methods</p> <p>Forty-five older adults (M age = 74.8 years; SD = 5.7) were randomly assigned to either a) PT, b) ST, or c) control group (no exercise). Measures of self-efficacy (SE), satisfaction with physical function (SPF), and the Satisfaction with Life Scale (SWL) were assessed at baseline and following training. The resistance training conditions met 3 times per week for 12 weeks at an intensity of 70% 1 repetition maximum.</p> <p>Results</p> <p>A series of ANCOVA's comparing between group differences in change and controlling for baseline values revealed significant group differences in all three measures: SE (F_(2,31)= 9.77; p < .001); SPF (F_(2,32)= 3.36; p = .047); SWL (F_(2,31)= 4.76; p = .016). Follow up analyses indicated that the PT group reported significantly more change in SE, SPF, and SWL than the control group whereas the ST group reported greater change than the control group only in SE.</p> <p>Conclusion</p> <p>These pilot data indicate that high velocity power training may influence multiple levels of quality of life over and above the benefits gained through traditional strength training.</p

Investigation and assimilation of nitrogen from benthic sediments by threee species of coral

We quantified the nitrogen and enzyme hydrolyzable amino acid (EHAA) concentrations of sediments prior to and after corals sloughed, ingested, and egested sediments layered onto their surfaces, for the three coral species Siderastrea siderea, Agaricia agaricites, and Porites astreoides in Jamaica. The percent nitrogen of the sediments egested by all three species was lower than in the sediments available to the corals. Additionally, the sediments sloughed (not ingested) by A. agaricites and P. astreoides were lower in percent nitrogen, while the sediments sloughed by S. siderea had the same percent nitrogen as that of the available sediments. The percent nitrogen of the sediments sloughed and egested by P. astreoides showed significant negative and positive relationships, respectively, to increasing sediment loads, while the percent nitrogen of the sediments sloughed and egested by both S. siderea and A. agaricites showed no relationship to sediment load. EHAA concentrations were not significantly different between the sloughed and available sediments but were significantly lower in the sediments egested by S. siderea and A. agaricites (EHAA concentrations were not measured for P. astreodies sediment fractions). Comparisons of the nitrogen and EHAA concentrations in the sloughed and egested sediments to what was available prior to coral processing show that maximum ingestion was between 0.1 and 0.2 µg N µg−1 coral N cm−2 and between 0.5 and 0.6 µg EHAA·cm−2. Maximum assimilation efficiencies were estimated to be 30–60% of the available nitrogen. The data show that corals ingest and alter the nitrogen concentration of particles that land on their surfaces. The corals’ abilities to process these sediments, and the sediments’ possible contributions to coral nutrition, are discussed based on these results

Kinematics of gait in Golden Retriever Muscular Dystrophy

The goal of this study was to quantify the two-dimensional kinematics of pathologic gait during overground walking at a self-selected speed at the stifle (knee) and hock (ankle) joints in six Golden Retriever Muscular Dystrophy (GRMD) dogs and six carrier littermates (controls). We found that GRMD dogs walked significantly slower than controls (p < 0.01). At the stifle joint, both groups displayed similar ROM (range of motion), but compared to controls, GRMD dogs walked with the stifle joint relatively more extended. At the hock joint, GRMD dogs displayed less ROM (range of motion) and walked with the joint relatively less flexed compared to controls. We controlled for gait speed in all analyses, so the differences we observed in joint kinematics between groups cannot be attributed solely to the slower walking speed of the GRMD dogs. This is the first kinematic study of gait in the GRMD dog, an important step in using this model in pre-clinical trials

Multiple Binding Sites for Fatty Acids on the Potassium Channel KcsA

Interactions of fatty acids with the potassium channel KcsA were studied using Trp fluorescence quenching and electron paramagnetic resonance (EPR) techniques. The brominated analogue of oleic acid was shown to bind to annular sites on KcsA and to the nonannular sites at each protein-protein interface in the homotetrameric structure with binding constants relative to dioleoylphosphatidylcholine of 0.67 ± 0.04 and 0.87 ± 0.08, respectively. Mutation of the two Arg residues close to the nonannular binding sites had no effect on fatty acid binding. EPR studies with a spin-labeled analogue of stearic acid detected a high-affinity binding site for the fatty acid with strong immobilization. Fluorescence quenching studies with the spin-labeled analogue showed that the binding site detected in the EPR experiments could not be one of the annular or nonannular binding sites. Instead, it is proposed that the EPR studies detect binding to the central hydrophobic cavity of the channel, with a binding constant in the range of ~0.1-1 ?M

The Third wave in globalization theory

This essay examines a proposition made in the literature that there are three waves in globalization theory—the globalist, skeptical, and postskeptical or transformational waves—and argues that this division requires a new look. The essay is a critique of the third of these waves and its relationship with the second wave. Contributors to the third wave not only defend the idea of globalization from criticism by the skeptics but also try to construct a more complex and qualified theory of globalization than provided by first-wave accounts. The argument made here is that third-wave authors come to conclusions that try to defend globalization yet include qualifications that in practice reaffirm skeptical claims. This feature of the literature has been overlooked in debates and the aim of this essay is to revisit the literature and identify as well as discuss this problem. Such a presentation has political implications. Third wavers propose globalist cosmopolitan democracy when the substance of their arguments does more in practice to bolster the skeptical view of politics based on inequality and conflict, nation-states and regional blocs, and alliances of common interest or ideology rather than cosmopolitan global structures

Geochemistry and petrogenesis of the Etendeka volcanic rocks from SWA Namibia

The volcanic rocks of the Etendeka Formation from north-west SWA/Namibia have a present-day coverage of 70,000 km² and comprise a series of interbedded basalts, latites and quartz latites, together with four varieties of intrusive dolerite. Apart from one group of dolerites (regional dolerites) which have mineralogical and geochemical similarities to the Lesotho Formation lavas from the Central area, the Etendeka volcanics differ from all other Karoo volcanics by virtue of their Cretaceous age, stratigraphy, mineralogy, geochemistry, and range in mineralogical, elemental and isotopic compositions for the basaltic rocks

Disordered macrophage cytokine secretion underlies impaired acute inflammation and bacterial clearance in Crohn's disease

The cause of Crohn's disease (CD) remains poorly understood. Counterintuitively, these patients possess an impaired acute inflammatory response, which could result in delayed clearance of bacteria penetrating the lining of the bowel and predispose to granuloma formation and chronicity. We tested this hypothesis in human subjects by monitoring responses to killed Escherichia coli injected subcutaneously into the forearm. Accumulation of 111In-labeled neutrophils at these sites and clearance of 32P-labeled bacteria from them were markedly impaired in CD. Locally increased blood flow and bacterial clearance were dependent on the numbers of bacteria injected. Secretion of proinflammatory cytokines by CD macrophages was grossly impaired in response to E. coli or specific Toll-like receptor agonists. Despite normal levels and stability of cytokine messenger RNA, intracellular levels of tumor necrosis factor (TNF) were abnormally low in CD macrophages. Coupled with reduced secretion, these findings indicate accelerated intracellular breakdown. Differential transcription profiles identified disease-specific genes, notably including those encoding proteins involved in vesicle trafficking. Intracellular destruction of TNF was decreased by inhibitors of lysosomal function. Together, our findings suggest that in CD macrophages, an abnormal proportion of cytokines are routed to lysosomes and degraded rather than being released through the normal secretory pathway

Susceptibility of hamsters to clostridium difficile isolates of differing toxinotype

Clostridium difficile is the most commonly associated cause of antibiotic associated disease (AAD), which caused ~21,000 cases of AAD in 2011 in the U.K. alone. The golden Syrian hamster model of CDI is an acute model displaying many of the clinical features of C. difficile disease. Using this model we characterised three clinical strains of C. difficile, all differing in toxinotype; CD1342 (PaLoc negative), M68 (toxinotype VIII) and BI-7 (toxinotype III). The naturally occurring non-toxic strain colonised all hamsters within 1-day post challenge (d.p.c.) with high-levels of spores being shed in the faeces of animals that appeared well throughout the entire experiment. However, some changes including increased neutrophil influx and unclotted red blood cells were observed at early time points despite the fact that the known C. difficile toxins (TcdA, TcdB and CDT) are absent from the genome. In contrast, hamsters challenged with strain M68 resulted in a 45% mortality rate, with those that survived challenge remaining highly colonised. It is currently unclear why some hamsters survive infection, as bacterial and toxin levels and histology scores were similar to those culled at a similar time-point. Hamsters challenged with strain BI-7 resulted in a rapid fatal infection in 100% of the hamsters approximately 26 hr post challenge. Severe caecal pathology, including transmural neutrophil infiltrates and extensive submucosal damage correlated with high levels of toxin measured in gut filtrates ex vivo. These data describes the infection kinetics and disease outcomes of 3 clinical C. difficile isolates differing in toxin carriage and provides additional insights to the role of each toxin in disease progression