7,178 research outputs found
Sea breeze: Induced mesoscale systems and severe weather
Sea-breeze-deep convective interactions over the Florida peninsula were investigated using a cloud/mesoscale numerical model. The objective was to gain a better understanding of sea-breeze and deep convective interactions over the Florida peninsula using a high resolution convectively explicit model and to use these results to evaluate convective parameterization schemes. A 3-D numerical investigation of Florida convection was completed. The Kuo and Fritsch-Chappell parameterization schemes are summarized and evaluated
Heart failure after conventional metal-on-metal hip replacements: a retrospective cohort study
Background and purpose - It is unclear whether metal particles and ions produced by mechanical wear and corrosion of hip prostheses with metal-on-metal (MoM) bearings have systemic adverse effects on health. We compared the risk of heart failure in patients with conventional MoM total hip arthroplasty (THA) and in those with metal-on-polyethylene (MoP) THA. Patients and methods - We conducted a retrospective cohort study using data from the Australian Government Department of Veterans' Affairs health claims database on patients who received conventional THA for osteoarthritis between 2004 and 2012. The MoM THAs were classified into groups: Articular Surface Replacement (ASR) XL Acetabular System, other large-head (LH) (> 32 mm) MoM, and small-head (SH) (≤ 32 mm) MoM. The primary outcome was hospitalization for heart failure after THA. Results - 4,019 patients with no history of heart failure were included (56% women). Men with an ASR XL THA had a higher rate of hospitalization for heart failure than men with MoP THA (hazard ratio (HR) = 3.2, 95% CI: 1.6-6.5). No statistically significant difference in the rate of heart failure was found with the other LH MoM or SH MoM compared to MoP in men. There was no statistically significant difference in heart failure rate between exposure groups in women. Interpretation - An association between ASR XL and hospitalization for heart failure was found in men. While causality between ASR XL and heart failure could not be established in this study, it highlights an urgent need for further studies to investigate the possibility of systemic effects associated with MoM THA.Marianne H Gillam, Nicole L Pratt, Maria C S Inacio, Elizabeth E Roughead, Sepehr Shakib, Stephen J Nicholls & Stephen E Grave
CYP-mediated drug-drug interactions with evacetrapib, an investigational CETP inhibitor: in vitro prediction and clinical outcome
AIMS Evacetrapib is a cholesteryl ester transfer protein (CETP) inhibitor under development for reducing cardiovascular events in patients with high risk vascular disease. CETP inhibitors are likely to be utilized as ‘add-on’ therapy to statins in patients receiving concomitant medications, so the potential for evacetrapib to cause clinically important drug–drug interactions (DDIs) with cytochromes P450 (CYP) was evaluated. METHODS The DDI potential of evacetrapib was investigated in vitro, followed by predictions to determine clinical relevance. Potential DDIs with possible clinical implications were then investigated in the clinic. RESULTS In vitro, evacetrapib inhibited all of the major CYPs, with inhibition constants (Ki) ranging from 0.57 μM (CYP2C9) to 7.6 μM (CYP2C19). Evacetrapib was a time-dependent inhibitor and inducer of CYP3A. The effects of evacetrapib on CYP3A and CYP2C9 were assessed in a phase 1 study using midazolam and tolbutamide as probe substrates, respectively. After 14 days of daily dosing with evacetrapib (100 or 300 mg), midazolam exposures (AUC) changed by factors (95% CI) of 1.19 (1.06, 1.33) and 1.44 (1.28, 1.62), respectively. Tolbutamide exposures (AUC) changed by factors of 0.85 (0.77, 0.94) and 1.06 (0.95, 1.18), respectively. In a phase 2 study, evacetrapib 100 mg had minimal impact on AUC of co-administered simvastatin vs. simvastatin alone with a ratio of 1.25 (1.03, 1.53) at steady-state, with no differences in reported hepatic or muscular adverse events. CONCLUSIONS Taken together, the extent of CYP-mediated DDI with the potential clinical dose of evacetrapib is weak and clinically important DDIs are not expected to occur in patients taking concomitant medications.Ellen A. Cannady, Jeffrey G. Suico, Ming-Dauh Wang, Stuart Friedrich, Jessica R. F. Rehmel, Stephen J. Nicholls, Kathryn A. Kruege
EVIDENCE AGAINST AN INTERACTION OF ANGIOTENSIN II WITH THE SYMPATHETIC NERVOUS SYSTEM IN MAN
Animal experiments indicate that angiotensin II can, under some circumstances stimulate the sympathetic nervous system at a number of different sites. In order to determine whether such a relationship of the renin-angiotensin and sympathetic nervous system exists in man, we increased (by intravenous infusion), or decreased (by administering the oral converting enzyme inhibitor captopril) circulating angiotensin II levels and monitored plasma adrenaline and nor-adrenaline responses. Angiotensin II infusions did not increase plasma catechol-amines, and lowering of angiotensin II by captopril treatment in patients with severe hypertension or congestive heart failure failed to alter plasma adrenaline or nor-adrenaline levels. Whether physiological levels of angiotensin II are capable of interacting directly with the sympathetic nervous system in man remains to be demonstrated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73600/1/j.1365-2265.1981.tb00684.x.pd
Measuring Temperature Gradients over Nanometer Length Scales
When a quantum dot is subjected to a thermal gradient, the temperature of
electrons entering the dot can be determined from the dot's thermocurrent if
the conductance spectrum and background temperature are known. We demonstrate
this technique by measuring the temperature difference across a 15 nm quantum
dot embedded in a nanowire. This technique can be used when the dot's energy
states are separated by many kT and will enable future quantitative
investigations of electron-phonon interaction, nonlinear thermoelectric
effects, and the effciency of thermoelectric energy conversion in quantum dots.Comment: 6 pages, 5 figure
Setting the stage: social-environmental and motivational predictors of optimal training engagement
In this paper, we will firstly explore the central tenets of SDT. Research that has examined the social-environmental and motivation-related correlates of optimal training, performance and health-related engagement through the theoretical lens of SDT will be reviewed. Drawing from SDT-driven work undertaken in educational, sport and dance settings, we will draw conclusions and suggest future directions from a research and applied perspective
- …