47 research outputs found

    Design study of a novel regenerative pump using experimental and numerical techniques

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    This paper presents a numerical and experimental analysis of a new regenerative pump design. The complex flow-field within regenerative pumps represents a significant challenge to previous published mathematical models. The new pump design incorporates a new axial inlet and outlet port. The experimental and numerical results demonstrate that it is not only possible to resolve the flowfield for this pump type but also demonstrates this pump as a viable alternative to other kinetic rotodynamic machines. The use of the latest rapid manufacturing techniques have enabled the production of the complex geometry of the axial ports required for the new configuration

    Effectiveness of a web-based self-help tool to reduce problem gambling: A randomized controlled trial.

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    Problem gambling constitutes a public health concern associated with psychopathological comorbidity, substance use, and financial difficulties. Most individuals with gambling problems avoid counseling services due to perceived stigma and their preference for self-reliance. Treatment accessibility could be improved through web-based interventions. We recruited 360 individuals with gambling problems and randomized them to a web-based intervention (n = 185) or an active control group consisting of a self-help manual for problem gambling (n = 175). The primary outcome was the number of days of gambling in the last 30 days. Secondary outcomes included money spent in the last 30 days, time gambling in the last 7 days, gambling-related problems, consumption of alcohol and cigarettes, and psychopathological comorbidity measured at posttreatment and 6-month follow-up. The primary outcome decreased significantly for both groups, with no significant difference between the groups. There were significant group × time interactions according to the Gambling Symptom Assessment Scale (F = 8.83, p <0 .001), the Problem Gambling Severity Index (F = 3.54, p = 0.030), for cigarettes smoked in the last 7 days (F = 26.68, p < 0.001), the Patient Health Questionnaire-9 (F = 19.41, p <0 .001), and the Generalized Anxiety Disorder-7 (F = 41.09, p <0 .001) favoring the intervention group. We experienced an overall high dropout rate (76%). Win Back Control seems to be an effective low-threshold treatment option for individuals with gambling problems that might otherwise be unapproachable for outpatient treatment services. Nevertheless, the high dropout rate should be considered when interpreting the study results, as they may have introduced a degree of variability

    Entropy Crisis, Ideal Glass Transition and Polymer Melting: Exact Solution on a Husimi Cactus

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    We introduce an extension of the lattice model of melting of semiflexible polymers originally proposed by Flory. Along with a bending penalty, present in the original model and involving three sites of the lattice, we introduce an interaction energy that corresponds to the presence of a pair of parallel bonds and a second interaction energy associated with the presence of a hairpin turn. Both these new terms represent four-site interactions. The model is solved exactly on a Husimi cactus, which approximates a square lattice. We study the phase diagram of the system as a function of the energies. For a proper choice of the interaction energies, the model exhibits a first-order melting transition between a liquid and a crystalline phase. The continuation of the liquid phase below this temperature gives rise to a supercooled liquid, which turns continuously into a new low-temperature phase, called metastable liquid. This liquid-liquid transition seems to have some features that are characteristic of the critical transition predicted by the mode-coupling theory.Comment: To be published in Physical Review E, 68 (2) (2003

    Effect of Sn on the Dehydrogenation Process of TiH2 in Al Foams

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    The study of the dehydrogenation process of TiH2 in aluminum foams produced by the powder metallurgy technique is essential to understanding its foaming behavior. Tin was added to the Al foam to modify the dehydrogenation process and stabilize the foam. A gradual decomposition and more retention of hydrogen gas can be achieved with Sn addition resulting in a gradual and larger expansion of the foam

    Cardiovascular risk factor control and outcomes in peripheral artery disease patients in the Reduction of Atherothrombosis for Continued Health (REACH) Registry

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    OBJECTIVES: To examine differences in risk factor (RF) management between peripheral artery disease (PAD) and coronary artery (CAD) or cerebrovascular disease (CVD), as well as the impact of RF control on major 1-year cardiovascular (CV) event rates. METHODS: The REACH Registry recruited >68000 outpatients aged >/=45 years with established atherothrombotic disease or >/=3 RFs for atherothrombosis. The predictors of RF control that were evaluated included: (1) patient demographics, (2) mode of PAD diagnosis, and (3) concomitant CAD and/or CVD. RESULTS: RF control was less frequent in patients with PAD (n=8322), compared with those with CAD or CVD (but no PAD, n=47492) [blood pressure; glycemia; total cholesterol; smoking cessation (each P<0.001)]. Factors independently associated with optimal RF control in patients with PAD were male gender (OR=1.9); residence in North America (OR=3.5), Japan (OR=2.5) or Latin America (OR=1.5); previous coronary revascularization (OR=1.3); and statin use (OR=1.4); whereas prior leg amputation was a negative predictor (OR=0.7) (P<0.001). Optimal RF control was associated with fewer 1-year CV ischemic symptoms or events. CONCLUSIONS: Patients with PAD do not achieve RF control as frequently as individuals with CAD or CVD. Improved RF control is associated with a positive impact on 1-year CV event rates

    HNF4a-deficient fatty liver provides a permissive environment for sex-independent hepatocellular carcinoma

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    ©©2019 American Association for Cancer Research. The incidence of hepatocellular carcinoma (HCC) is on the rise worldwide. Although the incidence of HCC in males is considerably higher than in females, the projected rates of HCC incidence are increasing for both sexes. A recently appreciated risk factor for HCC is the growing problem of nonalcoholic fatty liver disease, which is usually associated with obesity and the metabolic syndrome. In this study, we showed that under conditions of fatty liver, female mice were more likely to develop HCC than expected from previous models. Using an inducible knockout model of the tumor-suppressive isoform of hepatocyte nuclear factor 4 alpha ( P1-HNF4α ) in the liver in combination with prolonged high fat (HF) diet, we found that HCC developed equally in male and female mice as early as 38 weeks of age. Similar sex-independent HCC occurred in the STAM model of mice, in which severe hyperglycemia and HF feeding results in rapid hepatic lipid deposition, fibrosis, and ultimately HCC. In both sexes, reduced P1-HNF4α activity, which also occurs under chronic HF diet feeding, increased hepatic lipid deposition and produced a greatly augmented circadian rhythm in IL6, a factor previously linked with higher HCC incidence in males. Loss of HNF4α combined with HF feeding induced epithelial–mesenchymal transition in an IL6-dependent manner. Collectively, these data provide a mechanism-based working hypothesis that could explain the rising incidence of aggressive HCC. Significance: This study provides a mechanism for the growing incidence of hepatocellular carcinoma in both men and women, which is linked to nonalcoholic fatty liver disease

    Summer and fall habitat of North Atlantic right whales (Eubalaena glacialis) inferred from satellite telemetry

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    Author Posting. © National Research Council Canada, 2005. This article is posted here by permission of National Research Council Canada for personal use, not for redistribution. The definitive version was published in Canadian Journal of Fisheries and Aquatic Sciences 62 (2005): 527-543, doi:10.1139/F04-238.Satellite-monitored radio tags were attached to North Atlantic right whales (Eubalaena glacialis) in Grand Manan Basin of the lower Bay of Fundy during the summer and early fall seasons of 1989–1991 and 2000. Monte Carlo tests were used to examine the distribution of the tagged whales in space and time and with respect to a variety of environmental variables to characterize right whale habitat on their northern feeding grounds. These environmental variables included depth, depth gradient, climatological surface and bottom hydrographic properties, and remotely sensed surface temperature, chlorophyll concentration, and their respective horizontal gradients. Site fidelity in the Bay of Fundy was very low during 1989–1991 and high during 2000. When the tagged animals left the Bay, they did not frequently visit the deep basins of the Gulf of Maine and Scotian Shelf, where abundances of their primary copepod prey, Calanus finmarchicus, are thought to be high. Instead, right whales visited areas characterized by low bottom water temperatures, high surface salinity, and high surface stratification. No evidence was found that the tagged right whales associated with oceanic fronts or regions with high standing stocks of phytoplankton.This study was supported by the Office of Naval Research, National Marine Fisheries Service, Oregon State University Marine Mammal Endowment, and the Space Grant and Earth System Science fellowship programs of the National Aeronautics and Space Administration
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