2,231 research outputs found
Preliminary Results from an Experimental Assessment of a Natural Laminar Flow Design Method
A 5.2% scale semispan model of the new Common Research Model with Natural Laminar Flow (CRM-NLF) was tested in the National Transonic Facility (NTF) at the NASA Langley Research Center. The model was tested at transonic cruise flight conditions with Reynolds numbers based on mean aerodynamic chord ranging from 10 to 30 million. The goal of the test was to experimentally validate a new design method, referred to as Crossflow Attenuated NLF (CATNLF), which shapes airfoils to have pressure distributions that delay transition on wings with high sweep and Reynolds numbers. Additionally, the test aimed to characterize the NTF laminar flow testing capabilities, as well as establish best practices for laminar flow wind tunnel testing. Preliminary results regarding the first goal of validating the new design method are presented in this paper. Experimental data analyzed in this assessment include surface pressure data and transition images. The surface pressure data acquired during the test agree well with computational fluid dynamics (CFD) results. Transition images at a variety of Reynolds numbers and angles of attack are presented and compared to computational transition predictions. The experimental data are used to assess transition due to a turbulent attachment line, as well as crossflow and Tollmien-Schlichting modal instabilities. Preliminary results suggest the CATNLF design method is successful at delaying transition on wings with high sweep. Initial analysis of the transition front images showed transition Reynolds numbers that exceed historic experimental values at similar sweep angles.
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Hubble flow variance and the cosmic rest frame
We characterize the radial and angular variance of the Hubble flow in the
COMPOSITE sample of 4534 galaxies, on scales in which much of the flow is in
the nonlinear regime. With no cosmological assumptions other than the existence
of a suitably averaged linear Hubble law, we find with decisive Bayesian
evidence (ln B >> 5) that the Hubble constant averaged in independent spherical
radial shells is closer to its asymptotic value when referred to the rest frame
of the Local Group, rather than the standard rest frame of the Cosmic Microwave
Background. An exception occurs for radial shells in the range 40/h-60/h Mpc.
Angular averages reveal a dipole structure in the Hubble flow, whose amplitude
changes markedly over the range 32/h-62/h Mpc. Whereas the LG frame dipole is
initially constant and then decreases significantly, the CMB frame dipole
initially decreases but then increases. The map of angular Hubble flow
variation in the LG rest frame is found to coincide with that of the residual
CMB temperature dipole, with correlation coefficient -0.92. These results are
difficult to reconcile with the standard kinematic interpretation of the motion
of the Local Group in response to the clustering dipole, but are consistent
with a foreground non-kinematic anisotropy in the distance-redshift relation of
0.5% on scales up to 65/h Mpc. Effectively, the differential expansion of space
produced by nearby nonlinear structures of local voids and denser walls and
filaments cannot be reduced to a local boost. This hypothesis suggests a
reinterpretation of bulk flows, which may potentially impact on calibration of
supernovae distances, anomalies associated with large angles in the CMB
anisotropy spectrum, and the dark flow inferred from the kinematic
Sunyaev-Zel'dovich effect. It is consistent with recent studies that find
evidence for a non-kinematic dipole in the distribution of distant radio
sources.Comment: 37 pages, 9 tables, 13 figures; v2 adds extensive new analysis
(including additional subsections, tables, figures); v3 adds a Monte Carlo
analysis (with additional table, figure) which further tightens the
statistical robustness of the dipole results; v4 adds further clarifications,
small corrections, references and discussion of Planck satellite results; v5
typos fixed, matches published versio
Human leukocyte antigen (HLA) class I frequencies in human T-cell lymphotropic virus type 1 (HTLV-1)-infected patients from Salvador-Brazil
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Previous issue date: 2011Escola Bahiana de Medicina e Saúde Pública. Salvador, BA, BrasilEscola Bahiana de Medicina e Saúde Pública. Salvador, BA, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Laboratório Avançado de Saúde Pública. Salvador, BA, BrasilEscola Bahiana de Medicina e Saúde Pública. Salvador, BA, BrasilNational Cancer Institute. Laboratory of Genomic Diversity. SAIC-Frederick, Inc. Frederick, Maryland, USAEscola Bahiana de Medicina e Saúde Pública. Salvador, BA, BrasilUniversity of Wisconsin–Madison. Wisconsin National Primate Center. Madison, Wisconsin, USANational Cancer Institute. Laboratory of Genomic Diversity. SAIC-Frederick, Inc. Frederick, Maryland, USAEscola Bahiana de Medicina e Saúde Pública. Salvador, BA, Brasil / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Laboratório Avançado de Saúde Pública. Salvador, BA, Brasi
Sustained low-dose treatment with the histone deacetylase inhibitor LBH589 induces terminal differentation of osteosarcoma cells
Histone deacetylase inhibitors (HDACi) were identified nearly four decades ago based on their ability to induce cellular differentiation. However, the clinical development of these compounds as cancer therapies has focused on their capacity to induce apoptosis in hematologic and lymphoid malignancies, often in combination with conventional cytotoxic agents. In many cases, HDACi doses necessary to induce these effects result in significant toxicity. Since osteosarcoma cells express markers of terminal osteoblast differentiation in response to DNA methyltransferase inhibitors, we reasoned that the epigenetic reprogramming capacity of HDACi might be exploited for therapeutic benefit. Here, we show that continuous exposure of osteosarcoma cells to low concentrations of HDACi LBH589 (Panobinostat) over a three-week period induces terminal osteoblast differentiation and irreversible senescence without inducing cell death. Remarkably, transcriptional profiling revealed that HDACi therapy initiated gene signatures characteristic of chondrocyte and adipocyte lineages in addition to marked upregulation of mature osteoblast markers. In a mouse xenograft model, continuous low dose treatment with LBH589 induced a sustained cytostatic response accompanied by induction of mature osteoblast gene expression. These data suggest that the remarkable capacity of osteosarcoma cells to differentiate in response to HDACi therapy could be exploited for therapeutic benefit without inducing systemic toxicity
Was the Progenitor of the Sagittarius Stream a Disc Galaxy?
We use N-body simulations to explore the possibility that the Sagittarius
(Sgr) dwarf galaxy was originally a late-type, rotating disc galaxy, rather
than a non-rotating, pressure-supported dwarf spheroidal galaxy, as previously
thought. We find that bifurcations in the leading tail of the Sgr stream,
similar to those detected by the SDSS survey, naturally arise in models where
the Sgr disc is misaligned with respect to the orbital plane. Moreover, we show
that the internal rotation of the progenitor may strongly alter the location of
the leading tail projected on the sky, and thus affect the constraints on the
shape of the Milky Way dark matter halo that may be derived from modelling the
Sgr stream. Our models provide a clear, easily-tested prediction: although
tidal mass stripping removes a large fraction of the original angular momentum
in the progenitor dwarf galaxy, the remnant core should still rotate with a
velocity amplitude ~20 km/s that could be readily detected in future,
wide-field kinematic surveys of the Sgr dwarf.Comment: Letter accepted by MNRAS. N-body model animations can be downloaded
from http://www.ast.cam.ac.uk/~jorpega/files/sgr
Methodology for the effective stabilization of tin-oxide-based oxidation/reduction catalysts
The invention described herein involves a novel approach to the production of oxidation/reduction catalytic systems. The present invention serves to stabilize the tin oxide reducible metal-oxide coating by co-incorporating at least another metal-oxide species, such as zirconium. In one embodiment, a third metal-oxide species is incorporated, selected from the group consisting of cerium, lanthanum, hafnium, and ruthenium. The incorporation of the additional metal oxide components serves to stabilize the active tin-oxide layer in the catalytic process during high-temperature operation in a reducing environment (e.g., automobile exhaust). Moreover, the additional metal oxides are active components due to their oxygen-retention capabilities. Together, these features provide a mechanism to extend the range of operation of the tin-oxide-based catalyst system for automotive applications, while maintaining the existing advantages
Repeated Plyometric Exercise Attenuates Blood Glucose in Healthy Adults
International Journal of Exercise Science 10(7): 1076-1084, 2017. Plyometric exercise is popular in commercial exercise programs aiming to maximize energy expenditure for weight loss. However, the effect of plyometric exercise on blood glucose is unknown. The purpose of this study was to investigate the effect of relatively high intensity plyometric exercise on blood glucose. Thirteen subjects (6 females age= 21.8 ± 1.0 yrs.; height= 163.7 ± 7.8 cm; mass= 60.8 ± 6.7 kg and 7 males age= 22.0 ± 2.6 yrs.; height= 182.3 ± 3.6 cm; mass= 87.4 ± 12.5 kg) volunteered to participate. Subjects completed two random conditions on two separate days, consisting of either five sets of 10 maximal effort countermovement squat jumps (SJ) with 50 seconds’ rest between sets or quiet sitting (SIT) for the time equated to the SJ duration (~4min). Immediately after each condition, subjects drank 75g of anhydrous glucose (CHO) in 100ml of water. Blood glucose measurements were taken via finger prick pre and immediately post SJ or SIT, and 5, 15, 30, and 60 min post. A 2x6 (condition x time) ANOVA revealed a significant interaction where SJ blood glucose was lower at 15 (114.0 ± 14.6 mg/dl) and 30 (142.1 ± 22.5 mg/dl) min compared to SIT (15min 130.8 ± 14.0 mg/dl and 30min 159.3 ± 21.0 mg/dl). The current plyometric protocol attenuated CHO-induced blood glucose at 15 and 30 min. This may be due to increased physiological stress applied to the muscles, thus increasing muscular glucose uptake
Extracellular matrix remodelling in response to venous hypertension: proteomics of human varicose veins.
AIMS: Extracellular matrix remodelling has been implicated in a number of vascular conditions, including venous hypertension and varicose veins. However, to date, no systematic analysis of matrix remodelling in human veins has been performed. METHODS AND RESULTS: To understand the consequences of venous hypertension, normal and varicose veins were evaluated using proteomics approaches targeting the extracellular matrix. Varicose saphenous veins removed during phlebectomy and normal saphenous veins obtained during coronary artery bypass surgery were collected for proteomics analysis. Extracellular matrix proteins were enriched from venous tissues. The proteomics analysis revealed the presence of >150 extracellular matrix proteins, of which 48 had not been previously detected in venous tissue. Extracellular matrix remodelling in varicose veins was characterized by a loss of aggrecan and several small leucine-rich proteoglycans and a compensatory increase in collagen I and laminins. Gene expression analysis of the same tissues suggested that the remodelling process associated with venous hypertension predominantly occurs at the protein rather than the transcript level. The loss of aggrecan in varicose veins was paralleled by a reduced expression of aggrecanases. Chymase and tryptase β1 were among the up-regulated proteases. The effect of these serine proteases on the venous extracellular matrix was further explored by incubating normal saphenous veins with recombinant enzymes. Proteomics analysis revealed extensive extracellular matrix degradation after digestion with tryptase β1. In comparison, chymase was less potent and degraded predominantly basement membrane-associated proteins. CONCLUSION: The present proteomics study provides unprecedented insights into the expression and degradation of structural and regulatory components of the vascular extracellular matrix in varicosis
Complex exon-intron marking by histone modifications is not determined solely by nucleosome distribution
It has recently been shown that nucleosome distribution, histone modifications and RNA polymerase II (Pol II) occupancy show preferential association with exons (“exon-intron marking”), linking chromatin structure and function to co-transcriptional splicing in a variety of eukaryotes. Previous ChIP-sequencing studies suggested that these marking patterns reflect the nucleosomal landscape. By analyzing ChIP-chip datasets across the human genome in three cell types, we have found that this marking system is far more complex than previously observed. We show here that a range of histone modifications and Pol II are preferentially associated with exons. However, there is noticeable cell-type specificity in the degree of exon marking by histone modifications and, surprisingly, this is also reflected in some histone modifications patterns showing biases towards introns. Exon-intron marking is laid down in the absence of transcription on silent genes, with some marking biases changing or becoming reversed for genes expressed at different levels. Furthermore, the relationship of this marking system with splicing is not simple, with only some histone modifications reflecting exon usage/inclusion, while others mirror patterns of exon exclusion. By examining nucleosomal distributions in all three cell types, we demonstrate that these histone modification patterns cannot solely be accounted for by differences in nucleosome levels between exons and introns. In addition, because of inherent differences between ChIP-chip array and ChIP-sequencing approaches, these platforms report different nucleosome distribution patterns across the human genome. Our findings confound existing views and point to active cellular mechanisms which dynamically regulate histone modification levels and account for exon-intron marking. We believe that these histone modification patterns provide links between chromatin accessibility, Pol II movement and co-transcriptional splicing
Council tax valuation bands, socio-economic status and health outcome: a cross-sectional analysis from the Caerphilly Health and Social Needs Study
Council tax valuation bands (CTVBs) are a categorisation of household property value in Great Britain. The aim of the study was to assess the CTVB as a measure of socio-economic status by comparing the strength of the associations between selected health and lifestyle outcomes and CTVBs with two measures of socio-economic status: the National Statistics Socio-Economic Classification (NS-SEC) and the 2001 UK census-based Townsend deprivation index. METHODS: Cross-sectional analysis of data on 12,092 respondents (adjusted response 62.7%) to the Caerphilly Health and Social Needs Study, a postal questionnaire survey undertaken in Caerphilly county borough, south-east Wales, UK. The CTVB was assigned to each individual by matching the sampling frame to the local authority council tax register. Crude and age-gender adjusted odds ratios for each category of CTVB, NS-SEC and fifth of the ward distribution of Townsend scores were estimated for smoking, poor diet, obesity, and limiting long-term illness using logistic regression. Mean mental (MCS) and physical (PCS) component summary scores of the Short-Form SF-36 health status questionnaire were estimated in general linear models. RESULTS: There were significant trends in odds ratios across the CTVB categories for all outcomes, most marked for smoking and mental and physical health status. The adjusted odds ratio for being a smoker in the lowest versus highest CTVB category was 3.80 (95% CI: 3.06, 4.71), compared to 3.00 (95% CI: 2.30, 3.90) for the NS-SEC 'never worked and long-term unemployed' versus 'higher managerial and professional' categories, and 1.61 (95% CI: 1.42, 1.83) for the most deprived versus the least deprived Townsend fifth. The difference in adjusted mean MCS scores was 5.9 points on the scale for CTVB, 9.2 for NS-SEC and 3.2 for the Townsend score. The values for the adjusted mean PCS scores were 6.3 points for CTVB, 11.3 for NS-SEC, and 2.5 for the Townsend score. CONCLUSION: CTVBs assigned to individuals were strongly associated with the health and lifestyle outcomes modelled in this study. CTVBs are readily available for all residential properties and deserve further consideration as a proxy for socio-economic status in epidemiological studies in Great Britain
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