492 research outputs found

    Geohydrology of the McVille Aquifer Nelson County, Northeastern North Dakota

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    The McVille aquifer occupies a preglacial diversion trench in Upper Cretaceous shales. The trench is approximately 30 miles long, 1/4 to 3/4 miles wide, and crosses the southwestern half of the county in a southeasterly direction from T.152N., R.61W., to T.149N., R.58W. The aquifer materials are pleistocene glaciofluvial sands and gravel. Till, silt, and clay are also found in the trench and overlying the aquifer. Recharge is primarily through glacial outwash overlying the aquifer and occurs in the spring. Water is discharged to Stump Lake, a large closed lake, and to the Sheyenne River. A generalized representation of the flow system shows that water entering the aquifer in the south-central part of the country flows in two directions; southeast toward Griggs County and northwest toward Ramsey County. The water is mostly of the calcium-bicarbonate type in the southeastern section of the aquifer with a range of 273-935 mg/l total dissolved solids. Water in the northwestern section is of the sodium-bicarbonate or sulfate type with a range of 1200-2400 mg/l total dissolved solids

    Neurogenic Shock

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    Neurogenic shock is a state characterized by hypotension, bradycardia, and other evidence of autonomic dysfunction. The most common cause is acute spinal cord injury (SCI), which will be the subject of our focus. Because the typical autonomic reflexes may be either abolished or dysregulated, appropriate treatment requires an understanding of the neuroanatomic substrate for the change. In this chapter, we will explore the root cause for neurogenic shock, differentiating it from spinal shock, and discuss those patients at risk and generally accepted treatment paradigms. The timeframe for manifestation of neurogenic shock is variable and it can quickly progress to cause secondary injury or death, so appropriate monitoring requires a high level of suspicion and diligence

    Design approaches and materials processes for ultrahigh efficiency lattice mismatched multi-junction solar cells

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    In this study, we report synthesis of large area (>2cm^2), crack-free GaAs and GaInP double heterostructures grown in a multi-junction solar cell-like structure by MOCVD. Initial solar cell data are also reported for GaInP top cells. These samples were grown on Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer techniques. The double heterostructures exhibit radiative emission with uniform intensity and wavelength in regions not containing interfacial bubble defects. The minority carrier lifetime of ~1ns was estimated from photoluminescence decay measurements in both double heterostructures. We also report on the structural characteristics of heterostructures, determined via atomic force microscopy and transmission electron microscopy, and correlate these characteristics to the spatial variation of the minority carrier lifetime

    Surfing the Next Wave: Design and Implementation Challenges of Ubiquitous Computing

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    As computing becomes more mobile and pervasive, designing and implementing ubiquitous computing environments emerge as key challenges for information systems research and practice. The four short papers in this article report the highlights of the second Ubiquitous Computing Workshop at Case Western Reserve University in October 2003. The objectives of the papers are to set up a research agenda in this emerging interdisciplinary field, to share current level of understanding of leading edge research topics, and to create cumulative research streams in this field. Note: This paper consists of an overview of the second Ubiquitous Computing Workshop by its organizers, Kalle Lyytinen and Youngjin Yoo, followed by four papers summarizing its four major working groups. The four papers were prepared and can be read independently. They are not integrated

    Triglycerides promote lipid homeostasis during hypoxic stress by balancing fatty acid saturation

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    Lipid droplets, which store triglycerides and cholesterol esters, are a prominent feature of clear cell renal cell carcinoma (ccRCC). Although their presence in ccRCC is critical for sustained tumorigenesis, their contribution to lipid homeostasis and tumor cell viability is incompletely understood. Here we show that disrupting triglyceride synthesis compromises the growth of both ccRCC tumors and ccRCC cells exposed to tumor-like conditions. Functionally, hypoxia leads to increased fatty acid saturation through inhibition of the oxygen-dependent stearoyl-CoA desaturase (SCD) enzyme. Triglycerides counter a toxic buildup of saturated lipids, primarily by releasing the unsaturated fatty acid oleate (the principal product of SCD activity) from lipid droplets into phospholipid pools. Disrupting this process derails lipid homeostasis, causing overproduction of toxic saturated ceramides and acyl-carnitines as well as activation of the NF-κB transcription factor. Our work demonstrates that triglycerides promote homeostasis by “buffering” specific fatty acids

    GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates

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    In this study, we report synthesis of large area (> 2 cm^2) crack-free GaInP/GaAs double junction solar cells on 50 mm diameter Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer techniques. Defect removal from the template film and film surface prior to epitaxial growth was found to be critical to achievement of high open circuit voltage and efficiency. Cells grown on templates prepared with chemical mechanical polishing in addition a wet chemical etch show comparable performance to control devices grown on bulk Ge substrates. Current-voltage (I–V) data under AM 1.5 illumination indicate that the short circuit current is comparable in templated and control cells, but the open circuit voltage is slightly lower (2.08V vs. 2.16V). Spectral response measurements indicate a drop in open circuit voltage due to a slight lowering of the top GaInP cell band gap. The drop in band gap is due to a difference in the indium composition in the two samples caused by the different miscut (9° vs. 6°) of the two kinds of substrates

    Patient-reported outcomes of periacetabular osteotomy from the prospective ANCHOR cohort study

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    BACKGROUND: Current literature describing the periacetabular osteotomy (PAO) is mostly limited to retrospective case series. Larger, prospective cohort studies are needed to provide better clinical evidence regarding this procedure. The goals of the current study were to (1) report minimum 2-year patient-reported outcomes (pain, hip function, activity, overall health, and quality of life), (2) investigate preoperative clinical and disease characteristics as predictors of clinical outcomes, and (3) report the rate of early failures and reoperations in patients undergoing contemporary PAO surgery. METHODS: A large, prospective, multicenter cohort of PAO procedures was established, and outcomes at a minimum of 2 years were analyzed. A total of 391 hips were included for analysis (79% of the patients were female, and the average patient age was 25.4 years). Patient-reported outcomes, conversion to total hip replacement, reoperations, and major complications were documented. Variables with a p value of ≤0.10 in the univariate linear regressions were included in the multivariate linear regression. The backward stepwise selection method was used to determine the final risk factors of clinical outcomes. RESULTS: Clinical outcome analysis demonstrated major clinically important improvements in pain, function, quality of life, overall health, and activity level. Increasing age and a body mass index status of overweight or obese were predictive of improved results for certain outcome metrics. Male sex and mild acetabular dysplasia were predictive of lesser improvements in certain outcome measures. Three (0.8%) of the hips underwent early conversion to total hip arthroplasty, 12 (3%) required reoperation, and 26 (7%) experienced a major complication. CONCLUSIONS: This large, prospective cohort study demonstrated the clinical success of contemporary PAO surgery for the treatment of symptomatic acetabular dysplasia. Patient and disease characteristics demonstrated predictive value that should be considered in surgical decision-making. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence

    Polyfunctional Hiv-Specific Antibody Responses Are Associated with Spontaneous Hiv Control

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    Elite controllers (ECs) represent a unique model of a functional cure for HIV-1 infection as these individuals develop HIV-specific immunity able to persistently suppress viremia. Because accumulating evidence suggests that HIV controllers generate antibodies with enhanced capacity to drive antibody-dependent cellular cytotoxicity (ADCC) that may contribute to viral containment, we profiled an array of extra-neutralizing antibody effector functions across HIV-infected populations with varying degrees of viral control to define the characteristics of antibodies associated with spontaneous control. While neither the overall magnitude of antibody titer nor individual effector functions were increased in ECs, a more functionally coordinated innate immune–recruiting response was observed. Specifically, ECs demonstrated polyfunctional humoral immune responses able to coordinately recruit ADCC, other NK functions, monocyte and neutrophil phagocytosis, and complement. This functionally coordinated response was associated with qualitatively superior IgG3/IgG1 responses, whereas HIV-specific IgG2/IgG4 responses, prevalent among viremic subjects, were associated with poorer overall antibody activity. Rather than linking viral control to any single activity, this study highlights the critical nature of functionally coordinated antibodies in HIV control and associates this polyfunctionality with preferential induction of potent antibody subclasses, supporting coordinated antibody activity as a goal in strategies directed at an HIV-1 functional cure

    An Autoreactive Antibody from an SLE/HIV-1 Individual Broadly Neutralizes HIV-1

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    Broadly HIV-1–neutralizing antibodies (BnAbs) display one or more unusual traits, including a long heavy chain complementarity-determining region 3 (HCDR3), polyreactivity, and high levels of somatic mutations. These shared characteristics suggest that BnAb development might be limited by immune tolerance controls. It has been postulated that HIV-1–infected individuals with autoimmune disease and defective immune tolerance mechanisms may produce BnAbs more readily than those without autoimmune diseases. In this study, we identified an HIV-1–infected individual with SLE who exhibited controlled viral load (\u3c5,000 copies/ml) in the absence of controlling HLA phenotypes and developed plasma HIV-1 neutralization breadth. We collected memory B cells from this individual and isolated a BnAb, CH98, that targets the CD4 binding site (CD4bs) of HIV-1 envelope glycoprotein 120 (gp120). CH98 bound to human antigens including dsDNA, which is specifically associated with SLE. Anti-dsDNA reactivity was also present in the patient’s plasma. CH98 had a mutation frequency of 25% and 15% nt somatic mutations in the heavy and light chain variable domains, respectively, a long HCDR3, and a deletion in the light chain CDR1. The occurrence of anti-dsDNA reactivity by a HIV-1 CD4bs BnAb in an individual with SLE raises the possibility that some BnAbs and SLE-associated autoantibodies arise from similar pools of B cells

    Effect of promoter architecture on the cell-to-cell variability in gene expression

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    According to recent experimental evidence, the architecture of a promoter, defined as the number, strength and regulatory role of the operators that control the promoter, plays a major role in determining the level of cell-to-cell variability in gene expression. These quantitative experiments call for a corresponding modeling effort that addresses the question of how changes in promoter architecture affect noise in gene expression in a systematic rather than case-by-case fashion. In this article, we make such a systematic investigation, based on a simple microscopic model of gene regulation that incorporates stochastic effects. In particular, we show how operator strength and operator multiplicity affect this variability. We examine different modes of transcription factor binding to complex promoters (cooperative, independent, simultaneous) and how each of these affects the level of variability in transcription product from cell-to-cell. We propose that direct comparison between in vivo single-cell experiments and theoretical predictions for the moments of the probability distribution of mRNA number per cell can discriminate between different kinetic models of gene regulation.Comment: 35 pages, 6 figures, Submitte
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