Anionic lipids enriched at the ExPortal of Streptococcus pyogenes

The ExPortal of Streptococcus pyogenes is a membrane microdomain dedicated to the secretion and folding of proteins. We investigated the lipid composition of the ExPortal by examining the distribution of anionic membrane phospholipids. Staining with 10-N-nonyl-acridine orange revealed a single microdomain enriched with an anionic phospholipid whose staining characteristics and behavior in a cardiolipin-deficient mutant were characteristic of phosphatidylglycerol. Furthermore, the location of the microdomain corresponded to the site of active protein secretion at the ExPortal. These results indicate that the ExPortal is an asymmetric lipid microdomain, whose enriched content of anionic phospholipids may play an important role in ExPortal organization and protein trafficking

Evaluation and treatment of resistant hypertension

Hypertension is a major cause and contributor to stroke, heart and kidney disease. Despite the development of an arsenal of medication to treat hypertension over the past half-century, adequate treatment continues to be a major problem in the United States. The Third National Health and Nutrition Examination Survey (NHANES-III) shows that only 29% of hypertensive patients reach a blood pressure less than 140/90 mm Hg. Resistant hypertension is defined as a blood pressure greater than 140/90 mm Hg despite a rational combination of three or more blood pressure medications including a diuretic. The prevalence of true resistant hypertension in hypertension clinics is only about 11-13%. Higher prevalence rates are evident in populations with evidence of end-organ disease such as cardiac or renal disease where lower blood pressure targets have now been established. Ascertaining the possible cause(s) for resistant hypertension is a challenge to all clinicians, but critical in eventual determination of a therapeutic solution. The following review will hopefully help guide clinicians in their discernment of causes and potential treatments for resistant hypertension. The diagnosis and treatment of the more common secondary causes will be described and treatment options for patients with resistant hypertension are discussed. Newer options, some still under clinical investigation, will be described and their future utility will be discussed. (Cardiol J 2007; 14: 329-339

Endocarditis with aortic root pseudoaneurysm rupture

We report a case of aortic valve endocarditis complicated by aortic root pseudoaneurysm and rupture. (Cardiol J 2007; 14: 202-204

Toxic metal concentrations in cigarettes obtained from U.S. smokers in 2009 : results from the International Tobacco Control (ITC) United States survey cohort

This research was funded by grants from the U.S. National Cancer Institute (R01 CA100362 and P01 CA138389), and the Canadian Institutes of Health Research (115016). Geoffrey T. Fong was supported by a Senior Investigator Award from the Ontario Institute for Cancer Research (OICR) and a Prevention Scientist Award from the Canadian Cancer Society Research Institute.Smoking-related diseases can be attributed to the inhalation of many different toxins, including heavy metals, which have a host of detrimental health effects. The current study reports the levels of arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), and lead (Pb) in cigarettes obtained from adult smokers participating in the 2009 wave of the ITC United States Survey (N = 320). The mean As, Cd, Cr, Ni, and Pb levels were 0.17, 0.86, 2.35, 2.21, and 0.44 mu g/g, respectively. There were some differences in metal concentrations of cigarette brands produced by different manufacturers, suggesting differences in the source of tobaccos used by different companies. For Ni, there were significant pairwise differences between Philip Morris U.S. (PMUSA) and R.J. Reynolds (RJR) brands (PMUSA higher; p 0.10). Because of the variety of toxic heavy metals in cigarette tobacco, and their numerous negative health effects, metal content in cigarette tobacco should be reduced.Publisher PDFPeer reviewe

Autonomous Systems Taxonomy

The purpose of this taxonomy is to provide common definitions and a functional decomposition of the technology that is required for NASA's autonomous systems. The taxonomy serves as a framework for: (1) assessing the state of NASA's autonomous systems capability (workforce, technology, etc.) and (2) assessing the state of the art in autonomy technology

Online Multi-Modal Learning and Adaptive Information Trajectory Planning for Autonomous Exploration

In robotic information gathering missions, scientists are typically interested in understanding variables which require proxy measurements from specialized sensor suites to estimate. However, energy and time constraints limit how often these sensors can be used in a mission. Robots are also equipped with cheaper to use navigation sensors such as cameras. In this paper, we explore a challenging planning problem in which a robot is required to learn about a scientific variable of interest in an initially unknown environment by planning informative paths and deciding when and where to use its sensors. To tackle this we present two innovations: a Bayesian generative model framework to automatically learn correlations between expensive science sensors and cheaper to use navigation sensors online, and a sampling based approach to plan for multiple sensors while handling long horizons and budget constraints. Our approach does not grow in complexity with data and is anytime making it highly applicable to field robotics. We tested our approach extensively in simulation and validated it with real data collected during the 2014 Mojave Volatiles Prospector Mission. Our planning algorithm performs statistically significantly better than myopic approaches and at least as well as a coverage-based algorithm in an initially unknown environment while having added advantages of being able to exploit prior knowledge and handle other intricacies of the real world without further algorithmic modifications

Effect of Temperature on Abrasion Erosion in Particle Based Concentrating Solar Powerplants

The use of solid particles as a heat transfer medium is being explored for concentrated solar power plants (CSP) to increase their efficiency by achieving operating temperature \u3e700 °C. During operation, these hot particles are expected to move along the various components within the collector system, resulting in material degradation from a combination of high-temperature oxidation and erosion. In the present study, the performance of candidate materials was evaluated through a series of abrasion erosion experiments at room temperature as well as at 800 °C. Wear in metallic and refractory type materials was investigated using CarboBead® HSP 40/70 particles inside a resistance heated kiln. Cross-sectional scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) analysis on the specimens tested at 800 °C determined that the specific wear rate in Inconel 740H and stainless steel 316 metallic specimens was influenced by the thermally grown oxide morphology. High chromium Inconel 740H specimens exhibited greater resistance to wear with a steady state specific wear rate of 1.92E-4 mm3N-1m−1 compared to 5.7E-3 mm3N-1m−1 for Stainless Steel 316