Physical processes associated with current collection by plasma contactors

Recent flight data confirms laboratory observations that the release of neutral gas increases plasma sheath currents. Plasma contactors are devices which release a partially ionized gas in order to enhance the current flow between a spacecraft and the space plasma. Ionization of the expellant gas and the formation of a double layer between the anode plasma and the space plasma are the dominant physical processes. A theory is presented of the interaction between the contactor plasma and the background plasma. The conditions for formation of a double layer between the two plasmas are derived. Double layer formation is shown to be a consequence of the nonlinear response of the plasmas to changes in potential. Numerical calculations based upon this model are compared with laboratory measurements of current collection by hollow cathode-based plasma contactors

NASCAP/LEO calculations of current collection

NASCAP/LEO is a 3-dimensional computer code for calculating the interaction of a high-voltage spacecraft with the cold dense plasma found in Low Earth Orbit. Although based on a cubic grid structure, NASCAP/LEO accepts object definition input from standard computer aided design (CAD) programs so that a model may be correctly proportioned and important features resolved. The potential around the model is calculated by solving the finite element formulation of Poisson's equation with an analytic space charge function. Five previously published NASCAP/LEO calculations for three ground test experiments and two space flight experiments are presented. The three ground test experiments are a large simulated panel, a simulated pinhole, and a 2-slit experiment with overlapping sheaths. The two space flight experiments are a solar panel biased up to 1000 volts, and a rocket-mounted sphere biased up to 46 kilovolts. In all cases, the authors find good agreement between calculation and measurement

Our Taz

In memory of Professor Andrew Taslit

Prospectus, March 12, 1997

https://spark.parkland.edu/prospectus_1997/1008/thumbnail.jp

Prospectus, September 1, 1993

https://spark.parkland.edu/prospectus_1993/1012/thumbnail.jp

Cholesterol-induced macrophage apoptosis requires ER stress pathways and engagement of the type A scavenger receptor

Macrophage death in advanced atherosclerosis promotes necrosis and plaque destabilization. A likely cause of macrophage death is accumulation of free cholesterol (FC) in the ER, leading to activation of the unfolded protein response (UPR) and C/EBP homologous protein (CHOP)–induced apoptosis. Here we show that p38 MAPK signaling is necessary for CHOP induction and apoptosis. Additionally, two other signaling pathways must cooperate with p38-CHOP to effect apoptosis. One involves the type A scavenger receptor (SRA). As evidence, FC loading by non-SRA mechanisms activates p38 and CHOP, but not apoptosis unless the SRA is engaged. The other pathway involves c-Jun NH2-terminal kinase (JNK)2, which is activated by cholesterol trafficking to the ER, but is independent of CHOP. Thus, FC-induced apoptosis requires cholesterol trafficking to the ER, which triggers p38-CHOP and JNK2, and engagement of the SRA. These findings have important implications for understanding how the UPR, MAPKs, and the SRA might conspire to cause macrophage death, lesional necrosis, and plaque destabilization in advanced atherosclerotic lesions

Efficacy and Safety of Ertugliflozin in Patients With Type 2 Diabetes Mellitus and Established Cardiovascular Disease Treated With Metformin and Sulfonylurea

Abstract Introduction: Ertugliflozin (ERTU), a sodium-glucose cotransporter 2 (SGLT2) inhibitor, is approved as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus (T2DM). Aim: As a pre-specified sub-study of the Phase 3 VERTIS CV trial (NCT01986881), the efficacy and safety of ERTU were assessed in patients with T2DM and established atherosclerotic cardiovascular disease (ASCVD) inadequately controlled with metformin and sulfonylurea (SU). Methods: Patients with T2DM, established ASCVD, and HbA1c 7.0–10.5% on stable metformin (≥1500 mg/day) and SU doses as defined per protocol were randomized to once-daily ERTU (5 mg or 15 mg) or placebo. The primary sub-study objectives were to assess the effect of ERTU on HbA1c compared with placebo and to evaluate safety and tolerability during 18-week follow-up. Key secondary endpoints included proportion of patients achieving HbA1c <7%, fasting plasma glucose (FPG), body weight, and systolic blood pressure. Changes from baseline at Week 18 for continuous efficacy endpoints were assessed using a constrained longitudinal data analysis model. Results: Of the 8246 patients enrolled in the VERTIS CV trial, 330 patients were eligible for this sub-study (ERTU 5 mg, n=100; ERTU 15 mg, n=113; placebo, n=117). Patients had a mean (SD) age of 63.2 (8.4) years, T2DM duration 11.4 (7.4) years, estimated glomerular filtration rate 83.5 (17.8) mL/min/1.73 m2, and HbA1c 8.3% (1.0) (67.4 [10.6] mmol/mol). At Week 18, ERTU 5 mg and 15 mg were each associated with a significantly greater least squares mean (95% CI) HbA1c reduction from baseline versus placebo; the placebo-adjusted differences for ERTU 5 mg and 15 mg were –0.7% (–0.9, –0.4) and –0.8% (–1.0, –0.5), respectively (P<0.001). A higher proportion of patients in each ERTU group achieved HbA1c <7% relative to placebo (P<0.001). ERTU significantly reduced FPG and body weight (P<0.001, for each dose versus placebo), but not systolic blood pressure. Adverse events were reported in 48.0%, 54.9%, and 47.0% of patients in the ERTU 5 mg, 15 mg, and placebo groups, respectively. Genital mycotic infections were experienced by significantly higher proportions of male patients who received ERTU 5 mg and 15 mg (4.2% and 4.8%, respectively) versus placebo (0.0%; P≤0.05) and by a numerically, but not significantly, higher proportion of female patients who received ERTU 15 mg (10.3%) compared with placebo (3.8%) (P=0.36). The incidences of symptomatic hypoglycemia were 11.0% (5 mg), 12.4% (15 mg), and 7.7% (placebo), and of severe hypoglycemia 2.0% (5 mg), 1.8% (15 mg), and 0.9% (placebo). Conclusion: Among patients with T2DM and ASCVD, ERTU (5 mg and 15 mg) added to metformin and SU for 18 weeks improved glycemic control (HbA1c and FPG) and reduced body weight, and was generally well tolerated with a safety profile consistent with the SGLT2 inhibitor class

A Hall effect thruster plume model including large-angle elastic scattering

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76556/1/AIAA-2001-3355-806.pd

Fiction Fix 14

https://digitalcommons.unf.edu/fiction_fix/1009/thumbnail.jp