16,057 research outputs found
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Effect of Intravenous or Perivascular Injection of Synthetic Adrenocorticotropic Hormone on Stimulation Test Results in Dogs.
BackgroundStandard protocols for adrenocorticotropic hormone (ACTH) stimulation testing (ACTHst) often involve intravenous (IV) injection of corticotropin. ACTH might be unintentionally injected into the perivascular (PV) space.ObjectiveTo compare stimulation test results after IV and PV injections of ACTH.AnimalsTwenty privately owned dogs were studied: 10 healthy and 10 with trilostane-treated naturally occurring hyperadrenocorticism (HAC).MethodsProspective study. Each of 20 dogs underwent 2 ACTHst not <4 nor more than 14 days apart. Five healthy and 5 HAC dogs had an IV ACTHst first and PV second; 5 healthy and 5 HAC dogs had a PV ACTHst first and IV second. Blood samples for measurement of serum cortisol concentration were collected before and 1 hour after ACTH administration.ResultsNo significant difference in results was demonstrated when comparing serum cortisol concentrations after IV and PV ACTH administration in all 20 dogs (median Ī¼g/dL; interval Ī¼g/dL: 8.2; 1.4-17.4 versus 7.8; 0.9-16.9; P = .23). No significant difference in results was demonstrated when comparing serum cortisol concentrations after IV and PV ACTH administration in the 10 healthy dogs (median Ī¼g/dL; interval Ī¼g/dL: 10.9; 7.3-17.4 versus 10.6; 7.1-16.9; P = .54) or in the 10 HAC dogs (median Ī¼g/dL; interval Ī¼g/dL: 6.3; 1.4-8.6 versus 5.2; 0.9-8.7; P = .061).Conclusions and clinical importancePerivascular administration of ACTH does not significantly alter stimulation test results in healthy dogs or in dogs with HAC undergoing therapy with trilostane
Fast physical models for Si LDMOS power transistor characterization
A new nonlinear, process-oriented, quasi-two-dimensional (Q2D) model is described for microwave laterally diffused MOS (LDMOS) power transistors. A set of one-dimensional energy transport equations are solved across a two-dimensional cross-section in a ācurrent-drivenā form. The model accounts for avalanche breakdown and gate conduction, and accurately predicts DC and microwave characteristics at execution speeds sufficiently fast for circuit simulation applications
Reflected Light from Sand Grains in the Terrestrial Zone of a Protoplanetary Disk
We show that grains have grown to ~mm size (sand sized) or larger in the
terrestrial zone (within ~3 AU) of the protoplanetary disk surrounding the 3
Myr old binary star KH 15D. We also argue that the reflected light in the
system reaches us by back scattering off the far side of the same ring whose
near side causes the obscuration.Comment: 22 pages, 5 figures. To be published in Nature, March 13, 2008.
Contains a Supplemen
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A cryptotephra record from the Lake Victoria sediment core record of holocene palaeoenvironmental change
The sediment record from Lake Victoria is an important archive of regional environmental and climatic conditions, reaching back more than 15,000 cal. years before present (15 ka BP). As the largest lake by area in East Africa, its evolution is key to understanding regional palaeohydrological change during the late Pleistocene and Holocene, including controls on the Nile River flow. As well as important palaeoenvironmental proxies, the lake contains a unique record of explosive volcanism from the central Kenyan Rift, in the form of fine-grained volcanic ash (tephra) layers, interpreted as airfall deposits. In the V95-1P core, collected from the central northern basin of the lake, tephra layers vary in concentration from 10s to 10s of 1000s of glass shards per gram of sediment. None of the tephra are visible to the naked eye, and have only been revealed through careful laboratory processing. Compositional analyses of tephra glass shards has allowed the tephra layers to be correlated to previously unrecognized eruptions of Eburru volcano around 1.2 and 3.8 ka, and Olkaria volcano, prior to 15 ka. These volcanoes lie ~300 km east of the core site in the Kenyan Rift. Our results highlight the potential for developing cryptotephra analysis as a key tool in East African palaeolimnological research. Tephra layers offer opportunities for precise correlation of palaeoenvironmental sequences, as well as windows into the eruption frequency of regional volcanoes and the dispersal of volcanic ash. Leverhulme Trust Early Career Fellowshi
Structural performance of hybrid sandwich slabs under shear loading
In a hybrid panel with glass fiber reinforced polymer (GFRP) bottom skin and ribs, and deflection hardening cementitious composites (DHCC) top layer, it is very important to provide good shear connection between these various components in order to increase the load carrying capacity of the resulting hybrid slabs and a larger increment of deflection before the occurrence of the structural softening of this panel. The effectiveness of the proposed hybrid sandwich panels strongly depends on the performance of the shear connectors. The efficiency of indented shear connectors in improving the flexural performance of hybrid sandwich panels is here demonstrated. Since the efficiency of indented shear connectors in the hybrid sandwich panels is unknown, efforts are made in this paper in investigating the shear performance of hybrid slabs. A special focus is given on the indented shear connectorās behavior, considering different shear span ratios in ranges of 2.00, 1.39, and 0.77. In this regard, six hybrid sandwich panels were manufactured and experimentally tested under different shear loads. Then, the results are interpreted comprehensively.
The results obtained show that the GFRP rib thickness and height, and shear span ratios influence the damage events and the structural performance of the hybrid sandwich panels. Moreover, it was observed that using indented shear connectors in the hybrid slabs, regardless of the shear span ratios, provides high load capacity, high stiffness, and large residual deflection.The study presented in this paper is a part of the research project āRehabGFRP -
Rehabilitation of Building Floors with Lightweight High Performance GFRP Sandwich
Panelsā, with reference number of PTDC/ECM/113041/2009
Prostate Cancer Screening, Detection and Treatment Practices, Among Sub-Saharan African Urologists
Introduction: Prostate cancer is reported to be the leading cancer in men in Sub-Saharan Africa (SSA) and the number of prostate cancer deaths is expected to double in the next 20 years. Despite the importance of this public health issue in SSA, there remains relatively limited information about practices related to prostate cancer treatment in this population. Objective: We conducted a survey of 28 urology practices in SSA to evaluate the scope of available screening, detection and treatment. Materials and Methods: Screening was more commonly reported as a part of general medical care in South Africa (SA) compared with East or West (EW) Africa. However, use of digital Rectal Examination (DRE) and Prostate Specific Antigen (PSA) were used at similar rates for screening in all locations. Screening is primarily focused in men over age 50 and those with symptoms. Routine screening was the primary reason for screening use in SA, while symptoms were the primary reason for screening use in EW. Financial and cultural barriers to screening were more commonly reported in EW than SA. Similar detection approaches were used in all regions, with free PSA and PSA velocity being more commonly used in SA than EW. Six core biopsies were more commonly used in EW and 12 core biopsies were more common in SA. Trans urethral ultrasounds and bone scans were more commonly used in SA than EW. Treatment options were similar in all regions, with brachytherapy less likely to be used in EW than SA. Results: The descriptive data suggest that differences in patterns of screening, detection and treatment exist across Africa. Differences by geography may also reflect differences in SES and racial composition of the populations in each region.Key Words: Prostate cancer, Screening and Detection, Practice guidelines, Sub-Saharan Afric
The Association Between Menās Heath Behaviors and Interest in Workplace Health Promotion
Ā© 2019 The Author(s). Background: Predictors of menās health behaviors and interest in workplace health promotion are not well known. The aim of this study was to describe menās interest in workplace health promotion and associated health behaviors. Method: Male employees (N = 781) at six workplaces in British Columbia, Canada, were invited to complete a survey of their health behaviors, demographics, and interest in health promotion prior to implementation of a workplace health program. Findings: A total of 227 male employees (Mage = 43.6 years; SD = 12.1) completed the survey (response rate = 29%). Regarding health behaviors, 62.1% reported 150 weekly minutes of moderate-to-vigorous physical activity (MVPA), 29.3% consumed 5+ servings of fruit/vegetables per day, 56.8% reported 7+ hours sleep/night, 14.4% smoked, and 81.3% consumed alcohol. Men spent 50% of their workday sitting, and higher body mass index (BMI), higher income, and greater hours worked were related to greater hours sitting. Age was inversely related to MVPA. Alcohol consumption was lower among men who were older, had higher income, and worked fewer hours. Most men were interested in being physically active (85%), managing stress (85%), eating healthy (89%), and cancer screening (91%). Higher stage of change for physical activity (Ī² =.20, p =.003) and fruit/vegetable consumption (Ī² =.18, p =.027) were related to interest in these activities. Conclusions/Application to Practice: Occupational health providers should consider worker demographics and could support interventions that target individuals with varying levels of health behaviors given the importance of meeting the needs of often sedentary workers
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Unusual Formation of Point-Defect Complexes in the Ultrawide-Band-Gap Semiconductor Ī²-Ga2 O3
Understanding the unique properties of ultra-wide band gap semiconductors requires detailed information about the exact nature of point defects and their role in determining the properties. Here, we report the first direct microscopic observation of an unusual formation of point defect complexes within the atomic-scale structure of Ī²-Ga2O3 using high resolution scanning transmission electron microscopy (STEM). Each complex involves one cation interstitial atom paired with two cation vacancies. These divacancy-interstitial complexes correlate directly with structures obtained by density functional theory, which predicts them to be compensating acceptors in Ī²-Ga2O3. This prediction is confirmed by a comparison between STEM data and deep level optical spectroscopy results, which reveals that these complexes correspond to a deep trap within the band gap, and that the development of the complexes is facilitated by Sn doping through increased vacancy concentration. These findings provide new insight on this emerging material's unique response to the incorporation of impurities that can critically influence their properties
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