438 research outputs found

    Some one dimensional solutions of nonlinear waves of a rate sensitive, elastoplastic material Technical report, 1 Sep. 1967 - 31 Aug. 1972

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    One dimensional solution of nonlinear waves of rate sensitive, elastoplastic materia

    Pre-Privacy Amplification: A Post-Processing Technique for Quantum Key Distribution with Application to the Simplified Trusted Relay

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    Until quantum repeaters and quantum error correcting codes can be made commercially viable, long distance quantum key distribution (QKD) will continue to rely on trusted relay satellites. Strongly constrained by weight and power efficiency, little room is left for raw computational power, lowering the key rate per second. Efforts to reduce the computational burden on satellites, such as the simplified trusted relay (which does not participate in privacy amplification), come at a significant cost to their key rate per bit sent and maximum tolerable error rate. We construct a post processing technique, that acts as a sort of pre-privacy amplification that is performed before the usual error correction and privacy amplification steps. Loosely speaking, it provides a way to scale between the simplified trusted relay and the usual full trusted relay. For the asymptotic qubit six-state protocol, we demonstrate an increase in the maximum tolerable error rate from ∼12.62% to ∼12.83% for the full trusted relay, and from ∼9.05% to ∼11.7% for the simplified trusted relay. We also provide several sufficient conditions to determine when unique reduction matrices will yield identical key rates

    The Effects of Case-Based Instruction on Undergraduate Biology Students’ Understanding of the Nature of Science

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    Undergraduate science education is currently seeing a dramatic pedagogical push towards teaching the philosophies underpinning science as well as an increase in strategies that employ active learning. Many active learning strategies stem from constructivist ideals and have been shown to affect a student’s understanding of how science operates and its impact on society- commonly referred to as the nature of science (NOS). One particular constructivist teaching strategy, case-based instruction (CBI), has been recommended by researchers and science education reformists as an effective instructional strategy for teaching NOS. Furthermore, when coupled with explicit-reflective instruction, CBI has been found to significantly increasing understanding of NOS in elementary and secondary students. However, few studies aimed their research on CBI and NOS towards higher education. Thus, this study uses a quasi-experimental, nonequivalent group design to study the effects of CBI on undergraduate science students understandings of NOS. Undergraduate biology student’s understanding of NOS were assessed using the Views of Science Education (VOSE) instrument pre and post CBI intervention in Cellular and Molecular Biology and Human Anatomy and Physiology II. Data analysis indicated statistically significant differences between students NOS scores in experimental versus control sections for both courses, with experimental groups obtaining higher posttest scores. The results of this study indicate that undergraduate male and female students have similarly poor understandings of NOS and the use of historical case based instruction can be used as a means to increase undergraduate understanding of NOS

    A Systematic Review and Meta-Analysis of Proteomics Literature on the Response of Human Skeletal Muscle to Obesity/Type 2 Diabetes Mellitus (T2DM) Versus Exercise Training.

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    We performed a systematic review and meta-analysis of proteomics literature that reports human skeletal muscle responses in the context of either pathological decline associated with obesity/T2DM and physiological adaptations to exercise training. Literature was collected from PubMed and DOAJ databases following PRISMA guidelines using the search terms 'proteom*', and 'skeletal muscle' combined with either 'obesity, insulin resistance, diabetes, impaired glucose tolerance' or 'exercise, training'. Eleven studies were included in the systematic review, and meta-analysis was performed on a sub-set (four studies) of the reviewed literature that reported the necessary primary data. The majority of proteins (n = 73) more abundant in the muscle of obese/T2DM individuals were unique to this group and not reported to be responsive to exercise training. The main response of skeletal muscle to exercise training was a greater abundance of proteins of the mitochondrial electron transport chain, tricarboxylic acid cycle and mitochondrial respiratory chain complex I assembly. In total, five proteins were less abundant in muscle of obese/T2DM individuals and were also reported to be more abundant in the muscle of endurance-trained individuals, suggesting one of the major mechanisms of exercise-induced protection against the deleterious effects of obesity/T2DM occurs at complex I of the electron transport chain

    Age- and activity-related differences in the abundance of Myosin essential and regulatory light chains in human muscle

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    Traditional methods for phenotyping skeletal muscle (e.g., immunohistochemistry) are labor-intensive and ill-suited to multixplex analysis, i.e., assays must be performed in a series. Addressing these concerns represents a largely unmet research need but more comprehensive parallel analysis of myofibrillar proteins could advance knowledge regarding age- and activity-dependent changes in human muscle. We report a label-free, semi-automated and time efficient LC-MS proteomic workflow for phenotyping the myofibrillar proteome. Application of this workflow in old and young as well as trained and untrained human skeletal muscle yielded several novel observations that were subsequently verified by multiple reaction monitoring (MRM).We report novel data demonstrating that human ageing is associated with lesser myosin light chain 1 content and greater myosin light chain 3 content, consistent with an age-related reduction in type II muscle fibers. We also disambiguate conflicting data regarding myosin regulatory light chain, revealing that age-related changes in this protein more closely reflect physical activity status than ageing per se. This finding reinforces the need to control for physical activity levels when investigating the natural process of ageing. Taken together, our data confirm and extend knowledge regarding age- and activity-related phenotypes. In addition, the MRM transitions described here provide a methodological platform that can be fine-tuned to suite multiple research needs and thus advance myofibrillar phenotyping

    The reliability of data produced by isokinetic dynamometry (IKD) of knee extension and flexion movement

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    To investigate the feasibility of using isolated knee performance to measure the f-v profile of human muscle in vivo, we were using isokinetic dynamometry (IKD) technique that span the entire f-v profile of skeletal muscle. With institutional ethics approval, eleven healthy males (mean ± SD: age, 24.9 ± 3.1 years; body mass, 80.2 ± 10.1 kg; height, 176.2 ± 7.1 cm) completed this study. The participants were physically active and were familiarized with the techniques and protocol prior to completing 4 experimental sessions (1 introductory session and 3 repeated experiment sessions). The sessions was used a protocol of knee extensor function on IKD at isometric mode and angular velocities of 60˚.s-1, 120˚.s-1, 240˚.s-1 and 450˚.s-1. IKD data were not significantly different across the 3 repeated trials, demonstrating there was no evidence of systematic bias. The average coefficient of variation (CV) of IKD was 9.3 ± 3.0% ranging from 7.0 to 15.7%. Therefore the isolated knee performance to measure the f-v profile of human muscle in vivo using the IKD was feasible.Keywords: f-v profile, isokinetic dynamometry, skeletal muscl

    Mixed methods analysis of pig associated zoonoses in Lao PDR

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    Southeast Asia carries a large burden of endemic zoonotic diseases, in livestock and humans, especially in countries where livestock production is increasing among rural households for income generation and poverty reduction. This thesis explores the risk factors for transmission of pig-associated zoonoses – particularly Q fever, brucellosis, hepatitis E, and Japanese encephalitis – in northern Lao PDR, with a view to development of recommendations for “catch-all” control measures to impact on multiple diseases, improving biosecurity and preventing disease transmission to the human population. Research included (i) a qualitative assessment of the knowledge, attitudes, and practices of villagers related to pig-associated zoonoses and their risk factors using focus group methodology; (ii) an assessment of health seeking behaviour at hospital/health centre and village level to examine factors that influence choice of health care provider and determine the impact of health seeking behaviour on illness and treatment costs, and an examination of non-conventional health care sources to understand the complexity of health seeking behaviour and influences on choice of health care provider and, lastly, (iii) health care provider and service delivery assessments to determine healthcare facility routine service delivery procedures and assess capability in diagnosing and treating illness. In terms of disease, the most common illnesses reportedly seen by all those interviewed were respiratory illness, acute febrile illness and diarrhoea, confirming them as the leading causes of morbidity. Knowledge and awareness of the etiological agent of pig-associated zoonoses among villagers, patients, and health care providers was very poor for brucellosis and Q fever, with limited awareness of hepatitis E. Most were aware of Japanese encephalitis. Clinical diagnosis and symptomatic treatment of illness is the normal practice and identification of causative agents in human illness does not often occur. All three empirical assessments identified poor diagnostic capability as a major concern. Focus group discussions revealed that knowledge and awareness of disease risk factors, and of zoonoses in general, was low among villagers. Practices related to food consumption, latrine usage, hand hygiene and sanitation, which are known disease risk factors, were found to be a concern in study villages. Attitudes and practices adopted by villagers in relation to human and animal health and health seeking behaviours were strongly influenced by financial circumstances, access to appropriate healthcare facilities, spiritual beliefs, and a lack of knowledge and resources to maintain the health of both animals and humans. The first point of care when experiencing illness was often the health centre or a local traditional healer or spiritual healer or pharmacist/drug seller, depending on location. This was followed by the district hospital, if nearby. Many villagers described going back and forth between traditional medicine and modern medicine service providers, with 76% (19/25) of participants reportedly seeing more than one type of healthcare provider for a given episode of illness. Self-medication was the most common practice (84% of all participants) irrespective of the care provider consulted. Attendance at a healthcare facility was dependent on available funds and the perceived severity of illness. Overall household costs ranged between no cost, because of the “poor patient” policy that exempts vulnerable groups from paying for care, and $2500 USD for medical treatment, hospital stay, transportation and sometimes food. Healthcare workers at all facility levels (from health centre to provincial hospital) expressed a lack of confidence in making an accurate diagnosis for these pig associated zoonoses due to poor diagnostic capability in their respective facilities. A One Health approach to zoonotic disease surveillance that incorporates transdisciplinary methods and partnerships will lead to improved understanding of the underlining social determinants of health and their impact on health-seeking behaviours, disease transmission and ultimately disease reporting

    On the Rate of Synthesis of Individual Proteins within and between Different Striated Muscles of the Rat

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    The turnover of muscle protein is responsive to different (patho)-physiological conditions but little is known about the rate of synthesis at the level of individual proteins or whether this varies between different muscles. We investigated the synthesis rate of eight proteins (actin, albumin, ATP synthase alpha, beta enolase, creatine kinase, myosin essential light chain, myosin regulatory light chain and tropomyosin) in the extensor digitorum longus, diaphragm, heart and soleus of male Wistar rats (352 ± 30 g body weight). Animals were assigned to four groups (n = 3, in each), including a control and groups that received deuterium oxide (2H2O) for 4 days, 7 days or 14 days. Deuterium labelling was initiated by an intraperitoneal injection of 10 μL/g body weight of 99.9% 2H2O-saline, and was maintained by administration of 5% (v/v) 2H2O in drinking water provided ad libitum. Homogenates of the isolated muscles were analysed by 2-dimensional gel electrophoresis and matrix-assisted laser desorption ionisation time of flight mass spectrometry. Proteins were identified against the SwissProt database using peptide mass fingerprinting. For each of the eight proteins investigated, the molar percent enrichment (MPE) of 2H and rate constant (k) of protein synthesis was calculated from the mass isotopomer distribution of peptides based on the amino acid sequence and predicted number of exchangeable C–H bonds. The average MPE (2.14% ± 0.2%) was as expected and was consistent across muscles harvested at different times (i.e., steady state enrichment was achieved). The synthesis rate of individual proteins differed markedly within each muscle and the rank-order of synthesis rates differed among the muscles studied. After 14 days the fraction of albumin synthesised (23% ± 5%) was significantly (p < 0.05) greater than for other muscle proteins. These data represent the first attempt to study the synthesis rates of individual proteins across a number of different striated muscles

    Exercise-responsive phosphoproteins in the heart.

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    Endurance exercise improves cardiac performance and affords protection against cardiovascular diseases but the signalling events that mediate these benefits are largely unexplored. Phosphorylation is a widely studied post-translational modification involved in intracellular signalling, and to discover novel phosphorylation events associated with exercise we have profiled the cardiac phosphoproteome response to a standardised exercise test to peak oxygen uptake (VO2peak). Male Wistar rats (346±18g) were assigned to 3 independent groups (n=6, in each) that were familiarised with running on a motorised treadmill within a metabolic chamber. Animals performed a graded exercise test and were killed either immediately (0h) after or 3h after terminating the test at a standardised physiological end point (i.e. peak oxygen uptake; VO2peak). Control rats were killed at a similar time of day to the exercised animals, to minimise possible circadian effects. Cardiac proteins were digested with trypsin and phosphopeptides were enriched by selective binding to titanium dioxide (TiO2). Phosphopeptides were analysed by liquid chromatography and high-resolution tandem mass spectrometry, and phosphopeptides were quantified by MS1 intensities and identified against the UniProt knowledgebase using MaxQuant (data are available via ProteomeXchange, ID PXD006646). The VO2peak of rats in the 0h and 3h groups was 66±5mlkg(-1)min(-1) and 69.8±5mlkg(-1)min(-1), respectively. Proteome profiling detected 1169 phosphopeptides and one-way ANOVA found 141 significant (P<0.05 with a false discovery rate of 10%) differences. Almost all (97%) of the phosphosites that were responsive to exercise are annotated in the PhosphoSitePlus database but, importantly, the majority of these have not previously been associated with the cardiac response to exercise. More than two-thirds of the exercise-responsive phosphosites were different from those identified in previous phosphoproteome profiling of the cardiac response to β1-adrenergic receptor stimulation. Moreover, we report entirely new phosphorylation sites on 4 cardiac proteins, including S81 of muscle LIM protein, and identified 7 exercise-responsive kinases, including myofibrillar protein kinases such as obscurin, titin and the striated-muscle-specific serine/threonine kinase (SPEG) that may be worthwhile targets for future investigation
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