7,209 research outputs found
The United States Commercial Space Launch Competitiveness Act: The Creation of Private Space Property Rights and the Omission of the Right to Freedom From Harmful Interference
In March 2004, the European Space Agency successfully launched the Rosetta Spacecraft from Kourou, French Guiana. Over $1.5 billion dollars, ten years, and four billion miles later, the Rosetta Spacecraft released a sophisticated 220-pound probe called the “Philae,” which landed on Comet 67P/Churyumov-Gerasimenko on November 12, 2014. The landing on Comet 67P, the first of its kind, is one of the most recent technological advancements in space travel and exploration. During its year-long stay on Comet 67P, the Philae probe has drilled into the surface to collect samples, taken a series of photographs, and conducted a swath of experiments, all of which have provided never-before-seen data that has the potential to shed light on the origins of the universe.
Perhaps more important than the information gleaned from the Philae landing is the symbolic impact of the mission. The Philae landing establishes that humans possess—or will soon possess—the technology for extensive commercial enterprises in space. Specifically, proof of our ability to land on a comet makes the idea of landing on and potentially excavating an asteroid more realistic. Asteroids, comets’ similarly-situated cousins, present potentially extraordinary incentives for mining and exploitation. There are three types of asteroids: rare “M-class” asteroids, which contain ten times as much metal as other asteroids; “S-type” or stony asteroids; and “C-type” asteroids, which contain significant amounts of hydrated clay minerals. According to some estimates, certain “platinum-rich asteroids just 500 meters across could contain more than the entire known reserves of platinum group metals.” Additionally, because asteroids have very low gravity, the fuel required for landing and exiting is greatly diminished, making the potential cost of asteroid mining more palatable. Despite the tremendous amount of rare and precious minerals contained within asteroids, asteroid mining’s most valuable purpose may be derived from something that is already abundant on earth: water. Water, extracted from hydrated clay minerals present on asteroids, can be harvested and turned into hydrogen rocket fuel, giving asteroids the potential to be deep space gas stations. Plans to mine asteroids are not entirely new, as evidenced by the formation of several companies looking to extract resources from space enterprises
High-level endoscope disinfection processes in emerging economies: financial impact of manual process versus automated endoscope reprocessing
SummaryBackgroundThe use of flexible endoscopes is growing rapidly around the world. Dominant approaches to high-level disinfection among resource-constrained countries include fully manual cleaning and disinfection and the use of automated endoscope reprocessors (AERs). Suboptimal reprocessing at any step can potentially lead to contamination, with consequences to patients and healthcare systems.AimTo compare the potential results of guideline-recommended AERs to manual disinfection along three dimensions – productivity, need for endoscope repair, and infection transmission risk in India, China, and Russia.MethodsFinancial modelling using data from peer-reviewed published literature and country-specific market research.FindingsIn countries where revenue can be gained through productivity improvements, conversion to automated reprocessing has a positive direct impact on financial performance, paying back the capital investment within 14 months in China and seven months in Russia. In India, AER-generated savings and revenue offset nearly all of the additional operating costs needed to support automated reprocessing.ConclusionAmong endoscopy facilities in India and China, current survey-reported practices in endoscope reprocessing using manual soaking may place patients at risk of exposure to pathogens leading to infections. Conversion from manual soak to use of AERs, as recommended by the World Gastroenterology Organization, may generate cost and revenue offsets that could produce direct financial gains for some endoscopy units in Russia and China
Postprandial hyperlipidemia, endothelial dysfunction and cardiovascular risk: focus on incretins
Cardiovascular disease (CVD) risk in type 2 diabetes (T2DM) is only partially reduced by intensive glycemic control. Diabetic dyslipidemia is suggested to be an additional important contributor to CVD risk in T2DM. Multiple lipid lowering medications effectively reduce fasting LDL cholesterol and triglycerides concentrations and several of them routinely reduce CVD risk. However, in contemporary Western societies the vasculature is commonly exposed to prolonged postprandial hyperlipidemia. Metabolism of these postprandial carbohydrates and lipids yields multiple proatherogenic products. Even a transient increase in these factors may worsen vascular function and induces impaired endothelial dependent vasodilatation, a predictor of atherosclerosis and future cardiovascular events. There is a recent increased appreciation for the role of gut-derived incretin hormones in controlling the postprandial metabolic milieu. Incretin-based medications have been developed and are now used to control postprandial hyperglycemia in T2DM. Recent data indicate that these medications may also have profound effects on postprandial lipid metabolism and may favorably influence several cardiovascular functions. This review discusses (1) the postprandial state with special emphasis on postprandial lipid metabolism and its role in endothelial dysfunction and cardiovascular risk, (2) the ability of incretins to modulate postprandial hyperlipidemia and (3) the potential of incretin-based therapeutic strategies to improve vascular function and reduce CVD risk
Consequences of over-expression of rat Scavenger Receptor, SR-BI, in an adrenal cell model
BACKGROUND: The plasma membrane scavenger receptor, SR-BI, mediates the 'selective uptake' process by which cholesteryl esters (CE) from exogenously supplied HDL are taken up by target cells. Recent work suggests that dimer and higher order oligomeric forms of the SR-BI protein are important to this process. SR-BI has been shown to be particularly associated with microvilli and microvillar channels found at the cell surface of steroidogenic cells, and a study with the hormone stimulated adrenal gland has shown impressive changes in the size and complexity of the microvillar compartment as the mass of CE uptake (and accompanying steroidogenesis) fluctuates. In the present study, we examine a cell line in which we overexpress the SR-BI protein to determine if morphological, biochemical and functional events associated with SR-BI in a controlled cell system are similar to those observed in the intact mammalian adrenal which is responsive to systemic factors. METHODS: Y1-BS1 mouse adrenocortical cells were transiently transfected using rat SR-BI-pcDNA6-V5-His, rat SR-BI-pcDNA6-cMyc-His or control pcDNA6-V5-His vector construct using a CaPO(4 )precipitation technique. Twenty four hours after transfection, cells were treated with, or without, Bt(2)cAMP, and SR-BI expression, CE uptake, and steroidogenesis was measured. SR-BI dimerization and cell surface architectural changes were assessed using immunoelectron microscopic techniques. RESULTS: Overexpression of the scavenger receptor protein, SR-BI, in Y1-BS1 cells results in major alterations in cell surface architecture designed to increase uptake of HDL supplied-CEs. Changes include [1] the formation of crater-like erosions of the surface with multiple double membraned channel structures lining the craters, and [2] dimerized formations of SR-BI lining the newly formed craters and associated double membraned channels. CONCLUSION: These data show that overexpression of the scavenger receptor protein, SR-BI (accompanied by suitable hormone treatment and lipoproteins) in susceptible mammalian cells – is associated with increased cholesterol uptake and SR-BI dimerization within a much enlarged and architecturally complex microvillar compartment. These changes duplicate the structural, biochemical and functional changes related to the uptake of HDL CEs normally signaled by the action of ACTH on intact adrenal tissue
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