1,252 research outputs found

    Autonomous space processor for orbital debris

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    This work continues to develop advanced designs toward the ultimate goal of a GETAWAY SPECIAL to demonstrate economical removal of orbital debris utilizing local resources in orbit. The fundamental technical feasibility was demonstrated last year through theoretical calculations, quantitative computer animation, a solar focal point cutter, a robotic arm design and a subscale model. During this reporting period, several improvements are made in the solar cutter, such as auto track capabilities, better quality reflectors and a more versatile framework. The major advance has been in the design, fabrication and working demonstration of a ROBOTIC ARM that has several degrees of freedom. The functions were specifically tailored for the orbital debris handling. These advances are discussed here. Also a small fraction of the resources were allocated towards research in flame augmentation in SCRAMJETS for the NASP. Here, the fundamental advance was the attainment of Mach numbers up to 0.6 in the flame zone and a vastly improved injection system; the current work is expected to achieve supersonic combustion in the laboratory and an advanced monitoring system

    Characterization of the Lateral Distribution of Fluorescent Lipid in Binary-Constituent Lipid Monolayers by Principal Component Analysis

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    Lipid lateral organization in binary-constituent monolayers consisting of fluorescent and nonfluorescent lipids has been investigated by acquiring multiple emission spectra during measurement of each force-area isotherm. The emission spectra reflect BODIPY-labeled lipid surface concentration and lateral mixing with different nonfluorescent lipid species. Using principal component analysis (PCA) each spectrum could be approximated as the linear combination of only two principal vectors. One point on a plane could be associated with each spectrum, where the coordinates of the point are the coefficients of the linear combination. Points belonging to the same lipid constituents and experimental conditions form a curve on the plane, where each point belongs to a different mole fraction. The location and shape of the curve reflects the lateral organization of the fluorescent lipid mixed with a specific nonfluorescent lipid. The method provides massive data compression that preserves and emphasizes key information pertaining to lipid distribution in different lipid monolayer phases. Collectively, the capacity of PCA for handling large spectral data sets, the nanoscale resolution afforded by the fluorescence signal, and the inherent versatility of monolayers for characterization of lipid lateral interactions enable significantly enhanced resolution of lipid lateral organizational changes induced by different lipid compositions

    Using the Power of Questions to Organize for Progressive Education

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    Progressive education is widely admired and rarely implemented in schools. In this commentary, a group of educators—K-8 teachers and administrators and teacher education students and faculty—discuss their shared journey as they come together to study their own practice in schools committed to this model of teaching and learning. While acknowledging the reality that progressive education is most often found in in areas of economic privilege, they nonetheless challenge teachers to engage in “thoughtful participation, description, and dialogue,” in some fashion, as a means of counteracting the demands of the current reform climate

    PHOTOCHEMICAL RING-OPENING IN meso-CHLORINATED CHLOROPHYLLS

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    Irradiation of 20-chloro-chlorophylls of the a-type with visible light produces long-wavelength shifted photoproducts, which transform in the dark to linear tetrapyrroles (bile pigments). The possible significance for chlorophyll degradation is discussed

    Everything But the Merits: Analyzing the Procedural Aspects of the Healthcare Litigation

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    The role of States as Litigants in the Mandate Litigation Panel featured E. Duncan Getchell, Jr., Solicitor General of Virginia; William F. Brockman, Acting Solicitor General of Maryland; and William P. Marshall, the William Rand Kenan, Jr. Distinguished Professor of Law at the University of North Carolina School of Law. The Defining the Scope and Legal Effect of the Challenges to the Individual Mandate Panel featured Edward A. Hartnett, Richard J. Hughes Professor at the Seton Hall University School of Law; Tobias A. Dorsey, Special Counsel for the United States Sentencing Commission (USSC); and Kevin C. Walsh, Assistant Professor of Law at the University of Richmond School of Law The Situating the Mandate Litigation in the Broader Regulatory and Political Landscape Panel featured Bradley W. Joondeph, Santa Clara University School of Law, Creator of the ACA litigation blog; A. Christopher Bryant, Professor of Law at the University of Cincinnati College of Law; and Elizabeth Weeks Leonard, Associate Professor of Law at the University of Georgia Law School

    The kinetics and feedback inhibition of cytidine 5′-triphosphate synthetase in wild-type and mutant Chinese hamster cells

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    The kinetics and cytidine 5′-triphosphate (CTP) feedback inhibition of CTP synthetase in wild-type and four mutants of Chinese hamster V79 cells have been studied. The enzymes of the wild type and three of the four mutants exhibited positive cooperativity with the substrate uridine 5′-triphosphate (UTP). Three of the mutants had K m app and S 50 valuves distinctly greater than those of the wild type, while the fourth mutant had values similar to those of the wild type. all four mutants exhibited resistance to CTP feedback inhibition, while the wild type was sensitive to such inhibition. It is postulated that a single mutational event in each mutant had caused a concomitant change of the enzyme in its binding both to the substrate UTP and to the end-product CTP.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44151/1/10528_2004_Article_BF00485855.pd

    Paediatric non-progression following grandmother-to-child HIV transmission

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    Background In contrast to adult HIV infection, where slow disease progression is strongly linked to immune control of HIV mediated by protective HLA class I molecules such as HLA-B*81:01, the mechanisms by which a minority of HIV-infected children maintain normal-for-age CD4 counts and remain clinically healthy appear to be HLA class I-independent and are largely unknown. To better understand these mechanisms, we here studied a HIV-infected South African female, who remained a non-progressor throughout childhood. Results Phylogenetic analysis of viral sequences in the HIV-infected family members, together with the history of grand-maternal breast-feeding, indicated that, unusually, the non-progressor child had been infected via grandmother-to-child transmission. Although HLA-B*81:01 was expressed by both grandmother and grand-daughter, autologous virus in each subject encoded an escape mutation L188F within the immunodominant HLA-B*81:01-restricted Gag-specific epitope TL9 (TPQDLNTML, Gag 180–188). Since the transmitted virus can influence paediatric and adult HIV disease progression, we investigated the impact of the L188F mutant on replicative capacity. When this variant was introduced into three distinct HIV clones in vitro, viral replicative capacity was abrogated altogether. However, a virus constructed using the gag sequence of the non-progressor child replicated as efficiently as wildtype virus. Conclusion These findings suggest alternative sequences of events: the transmission of the uncompensated low fitness L188F to both children, potentially contributing to slow progression in both, consistent with previous studies indicating that disease progression in children can be influenced by the replicative capacity of the transmitted virus; or the transmission of fully compensated virus, and slow progression here principally the result of HLA-independent host-specific factors, yet to be defined

    May Measurement Month 2017: an analysis of blood pressure screening results from Australia - South-East Asia and Australasia

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    Increased blood pressure (BP) is the single biggest contributing risk factor to the global disease burden. May Measurement Month (MMM) is a global initiative of the International Society of Hypertension aimed at raising awareness of high BP. In Australia, hypertension affects around six million adults and continues to remain the greatest attributable cause of cardiovascular mortality and morbidity (48.3%), stroke deaths (28%), and kidney disease (14%). An opportunistic cross-sectional survey was carried out during May 2017 predominantly in capital cities across Australia which included adult volunteers. Blood pressure measurement, the definition of hypertension and statistical analysis followed the standard MMM protocol. Additional information obtained included anthropometric data and responses to questionnaires on demographic, lifestyle, and environmental factors. Data were collected from 3817 individuals. After multiple imputation, of the 3758 individuals for whom a mean of the second and third BP reading was available, 1188 (31.2%) had hypertension. Of 3213 individuals not receiving antihypertensive treatment, 591 (18.4%) were hypertensive, and 239 (40.1%) of the 596 individuals receiving treatment had uncontrolled BP. Adjusted BP was higher in association with antihypertensive medication, cerebrovascular disease, smoking, and alcohol consumption. Blood pressure was higher when measured on the right arm and on Tuesdays. MMM17 was one of the largest BP screening campaigns undertaken in Australia using standardized BP measurements. In line with previous surveys, around one-third of screened adults had hypertension and approximately 40% of treated individuals remained uncontrolled. These results suggest that opportunistic screening can identify significant numbers with raised BP
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