400 research outputs found

    Exposure to High Levels of Noise Poses Hazards and Risks for Development of Hypertension and Heart Disease: Potential Roles of Unrecognized Ionized Hypomagnesemia and Release of Ceramides and Platelet-Activating Factor

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    It has been demonstrated in numerous human and animal studies that audiogenic stress (AS) can induce elevation of arterial blood pressure and cardiac damage and that noise –induced hearing loss may be associated with alterations in magnesium (Mg) metabolism. Our laboratories, over a period of approximately 40 years, have been investigating why AS causes high blood pressure and cardiac damage. This review focuses on a number of newer discoveries on why AS causes dysfunctions of the cardiovascular system (CVS) This review discusses the pivotal physiological and biochemical importance of Mg to body health and the fact that most Americans and Europeans are deficient in daily Mg intake which perforce can cause severe dysfunctions of the CVS. Our ongoing studies clearly provide a solid microcirculatory basis for how and why AS above 65dB(A) often induces elevated blood pressure and cardiac damage. We review a body of data that points to the fact that AS does the latter, but appears to do so because noise stress levels result in Mg deficiency followed by release of certain sphingolipids (e.g., ceramides) and generation and release of platelet- activating factor (PDF). It is our opinion that all people exposed to high degrees of noise stress should be monitored for cardiovascular functions, ionized Mg levels, blood ceramide levels and levels of PDF. Lastly, we believe all people exposed to high levels of AS (i.e., maintenance people and pilots on aircraft carriers, musicians [particularly at rock concerts], motorman and conductors on trains and subways, construction site workers, etc.) should have at least the equivalent daily intake of 500-600 mg of Mg/day

    Potential Roles of Magnesium Deficiency in Inflammation and Atherogenesis: Importance and Cross-Talk of Platelet-Activating Factor and Ceramide

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    Epidemiologic studies in North America and Europe have shown that people consuming Western-type diets are low in magnesium (Mg) content (i.e., \u3c 30 - 65% of the RDA for Mg); most such diets in the USA show that 60 - 80% of Americans are consuming only 185 - 235 mg/day of Mg. Low Mg content in areas of soft-water, and Mg-poor soil, is associated with high incidences of ischemic heart disease (IHD), coronary artery disease, hypertension, and sudden cardiac death (SCD). It is clear that the leading underlying cause of death worldwide is atherosclerosis. Importantly, both animal and human studies have shown an inverse relationship between dietary intake of Mg and atherosclerosis. The myocardial level of Mg has consistently been observed to be lower in subjects dying from IHD and SCD in soft-water areas than those in hard-water areas. Over the past 20 years, our laboratories, using several types of primary cultured vascular smooth muscle (VSM) cells, and myocardial cells, demonstrated that declining levels of extracellular Mg ([Mg2+]0) activated several enzymatic pathways to produce increases in cellular sphingolipids, particularly ceramides which are known to exert numerous types of cardiovascular manifestations including inflammatory effects; the latter play important roles in atherogenesis and cardiovascular diseases. Approximately 20 years ago, we reported that low [Mg2+]0 caused formation of platelet-activating factor (PAF) as well as other types of PAF-like molecules and suggested that these molecules might be causative agents in low Mg2+- induced IHD and SCD. Herein, we review results and data from our labs which strongly support roles for ceramides, PAF and PAF-like lipids in low [Mg2+]0-induced IHD and SCD

    Solvent-Washable Polymer Templated Synthesis of Mesoporous Materials and Solic-Acid Nanocatalysts in One-Pot

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    We report a new and simple one-pot synthetic method to produce mesoporous silica and nanoporous solid acid catalyst capable of catalyzing pinacole-pinacolone rearrangement and esterification reactions, by preparing a solvent washable phosphonated triblock copolymer template and self-assembling it in the presence of alkoxysilane

    Euphoria from Drinking Alcoholic Beverages May Be Due to Reversible Constriction of Cerebral Blood Vessels: Potential Roles of Unrecognized Ionized Hypomagnesemia, and Release of Ceramides and Platelet-Activating Factor

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    The authors discuss the feeling of euphoria when drinking alcohol. They summarize studies that suggest this feeling is due to blood vessel constriction, and explain why they believe that the specific mechanism that results in euphoria is the rapid, reversible release o free magnesium ions ([Mg2+]) coupled to the release of ceramides and platelet-activating factor (PAF)

    Why Is There an Association Between Retinal Vein Occlusion, Vision Loss, Myocardial Infarction, Stroke and Mortality: Potential Roles of Hypomagnesaemia, Release of Sphingolipids, and Platelet-Activating Factor

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    Although numerous hypotheses (and potential risk factors), have been offered to explain the origins and potential mechanism(s) for central retinal vein occlusion (RVO) in patients of diverse ages, there is no agreement. Recently, considerable epidemiological evidence has been brought forth which indicates a strong association between RVO, myocardial infarctions, heart failure, and stroke. Magnesium (Mg) deficiency (mgD) has long-been associated with glaucoma and diabetic retinopathy. Over the past three decades, our laboratories have found strong associations of mgD linked to morbidity/ mortality in cardiovascular diseases such as myocardial infarctions, cardiac failure, atherogenesis, and strokes, both experimentally and clinically. More recently, we have reported direct links of mgD in these disease syndromes with generation and release of ceramides and platelet-activating factor (PAF). In this report, we present a novel hypothesis for a probable underlying mgD and release of ceramides and PAF as causal factors in development and progression of RVO. We believe this hypothesis could prove useful in the diagnosis and treatment of RVO

    Evaluation of impacts of future climate change and water use scenarios on regional hydrology

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    General circulation models (GCMs) have been widely used to simulate current and future climate at the global scale. However, the development of frameworks to apply GCMs to assess potential climate change impacts on regional hydrologic systems, ability to meet future water demand, and compliance with water resource regulations is more recent. In this study eight GCMs were bias-corrected and downscaled using the bias correction and stochastic analog (BCSA) downscaling method and then used, together with three ET0 methods and eight different water use scenarios, to drive an integrated hydrologic model previously developed for the Tampa Bay region in western central Florida. Variance-based sensitivity analysis showed that changes in projected streamflow were very sensitive to GCM selection, but relatively insensitive to ET0 method or water use scenario. Changes in projections of groundwater level were sensitive to both GCM and water use scenario, but relatively insensitive to ET0 method. Five of eight GCMs projected a decrease in streamflow and groundwater availability in the future regardless of water use scenario or ET method. For the business as usual water use scenario all eight GCMs indicated that, even with active water conservation programs, increases in public water demand projected for 2045 could not be met from ground and surface water supplies while achieving current groundwater level and surface water flow regulations. With adoption of 40&thinsp;% wastewater reuse for public supply and active conservation four of the eight GCMs indicate that 2045 public water demand could be met while achieving current environmental regulations; however, drier climates would require a switch from groundwater to surface water use. These results indicate a high probability of a reduction in future freshwater supply in the Tampa Bay region if environmental regulations intended to protect current aquatic ecosystems do not adapt to the changing climate. Broad interpretation of the results of this study may be limited by the fact that all future water use scenarios assumed that increases in water demand would be the result of intensification of water use on existing agricultural, industrial, and urban lands. Future work should evaluate the impacts of a range of potential land use change scenarios, with associated water use change projections, over a larger number of GCMs.</p

    Periodic Mesoporous Organosilica Nanorice

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    A periodic mesoporous organosilica (PMO) with nanorice morphology was successfully synthesized by a template assisted sol–gel method using a chain-type precursor. The PMO is composed of D and T sites in the ratio 1:2. The obtained mesoporous nanorice has a surface area of 753 m2 g−1, one-dimensional channels, and a narrow pore size distribution centered at 4.3 nm. The nanorice particles have a length of ca. 600 nm and width of ca. 200 nm

    Simple Systematic Synthesis of Periodic Mesoporous Organosilica Nanoparticles with Adjustable Aspect Ratios

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    One-dimensional periodic mesoporous organosilica (PMO) nanoparticles with tunable aspect ratios are obtained from a chain-type molecular precursor octaethoxy-1,3,5-trisilapentane. The aspect ratio can be tuned from 2:1 to >20:1 simply by variation in the precursor concentration in acidic aqueous solutions containing constant amounts of triblock copolymer Pluronic P123. The mesochannels are highly ordered and are oriented parallel to the longitudinal axis of the PMO particles. No significant Si–C bond cleavage occurs during the synthesis according to29Si MAS NMR. The materials exhibit surface areas between 181 and 936 m2 g−1

    Estimation of hydraulic conductivity and its uncertainty from grain-size data using GLUE and artificial neural networks

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    peer reviewedaudience: researcher, professionalVarious approaches exist to relate saturated hydraulic conductivity (Ks) to grain-size data. Most methods use a single grain-size parameter and hence omit the information encompassed by the entire grain-size distribution. This study compares two data-driven modelling methods, i.e.multiple linear regression and artificial neural networks, that use the entire grain-size distribution data as input for Ks prediction. Besides the predictive capacity of the methods, the uncertainty associated with the model predictions is also evaluated, since such information is important for stochastic groundwater flow and contaminant transport modelling. Artificial neural networks (ANNs) are combined with a generalized likelihood uncertainty estimation (GLUE) approach to predict Ks from grain-size data. The resulting GLUE-ANN hydraulic conductivity predictions and associated uncertainty estimates are compared with those obtained from the multiple linear regression models by a leave-one-out cross-validation. The GLUE-ANN ensemble prediction proved to be slightly better than multiple linear regression. The prediction uncertainty, however, was reduced by half an order of magnitude on average, and decreased at most by an order of magnitude. This demonstrates that the proposed method outperforms classical data-driven modelling techniques. Moreover, a comparison with methods from literature demonstrates the importance of site specific calibration. The dataset used for this purpose originates mainly from unconsolidated sandy sediments of the Neogene aquifer, northern Belgium. The proposed predictive models are developed for 173 grain-size -Ks pairs. Finally, an application with the optimized models is presented for a borehole lacking Ks data
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