1,305 research outputs found

    Development of heat flux sensors for turbine airfoils

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    The objectives of this program are to develop heat flux sensors suitable for installation in hot section airfoils of advanced aircraft turbine engines and to experimentally verify the operation of these heat flux sensors in a cylinder in a cross flow experiment. Embedded thermocouple and Gardon gauge sensors were developed and fabricated into both blades and vanes. These were then calibrated using a quartz lamp bank heat source and finally subjected to thermal cycle and thermal soak testing. These sensors were also fabricated into cylindrical test pieces and tested in a burner exhaust to verify heat flux measurements produced by these sensors. The results of the cylinder in cross flow tests are given

    Functional interaction between BMPR-II and Tctex-1, a light chain of Dynein, is isoform-specific and disrupted by mutations underlying primary pulmonary hypertension

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    Diverse heterozygous mutations of bone morphogenetic receptor type II (BMPR-II) underlie the inherited form of the vascular disorder primary pulmonary hypertension (PPH). As yet, the molecular detail of how such defects contribute to the pathogenesis of PPH remains unclear. BMPR-II is a member of the transforming growth factor-beta cell signalling superfamily. Ligand binding induces cell surface receptor complex formation and activates a cascade of phosphorylation events of intracellular intermediaries termed Smads, which initiate transcriptional regulation. Some 30% of PPH-causing mutations localize to exon 12, which may be spliced out forming an isoform depleted of the unusually long BMPR-II cytoplasmic tail. To further elucidate the consequences of BMPR2 mutation, we sought to characterize aspects of the cytoplasmic domain function by seeking intracellular binding partners. We now report that Tctex-1, a light chain of the motor complex dynein, interacts with the cytoplasmic domain of BMPR-II and demonstrate that Tctex-1 is phosphorylated by BMPR-II, a function disrupted by PPH disease causing mutations within exon 12. Finally we show that BMPR-II and Tctex-1 co-localize to endothelium and smooth muscle within the media of pulmonary arterioles, key sites of vascular remodelling in PPH. Taken together, these data demonstrate a discrete function for the cytoplasmic domain of BMPR-II and justify further investigation of whether the interaction with and phosphorylation of Tctex-1 contributes to the pathogenesis of PPH

    Halocarbon ozone depletion and global warming potentials

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    Concern over the global environmental consequences of fully halogenated chlorofluorocarbons (CFCs) has created a need to determine the potential impacts of other halogenated organic compounds on stratospheric ozone and climate. The CFCs, which do not contain an H atom, are not oxidized or photolyzed in the troposphere. These compounds are transported into the stratosphere where they decompose and can lead to chlorine catalyzed ozone depletion. The hydrochlorofluorocarbons (HCFCs or HFCs), in particular those proposed as substitutes for CFCs, contain at least one hydrogen atom in the molecule, which confers on these compounds a much greater sensitivity toward oxidation by hydroxyl radicals in the troposphere, resulting in much shorter atmospheric lifetimes than CFCs, and consequently lower potential for depleting ozone. The available information is reviewed which relates to the lifetime of these compounds (HCFCs and HFCs) in the troposphere, and up-to-date assessments are reported of the potential relative effects of CFCs, HCFCs, HFCs, and halons on stratospheric ozone and global climate (through 'greenhouse' global warming)

    The Effect of Information Feedback Upon Psychophysical Judgments

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    An analysis was made of the role of presentation schedules and information feedback on performance in a forced-choice signal detection task. The experimental results indicate that information feedback facilitates performance, but only for certain presentation schedules. The present study was designed to assess performance in a signal detection task under two conditions of information feedback. In the I-condition, S was told on each trial whether his detection response was correct or incorrect; in the !-condition S was given no feedback regarding the correctness of his response. The task involved a 2-response, forced-choice auditory detection problem. On each trial 2 temporal intervals were defined and S was required to report which interval he believed contained the signal; i. e., in one interval a tone burst in a background of white noise was presented, while the other interval contained only white noise. A trial will be denoted as s1 or s2, depending on whether the signal was embedded in the 1st or 2nd interval; the S's response will be denoted A1 or A2 to indicate which interval he reported contained the signal. The probability of an s1 trial will be denoted as y. In this study two values of y were used (.50 and.75) and, as indicated above, two conditions of information feedback. Thus there were 4 experimental conditions (501, 50I, 751, 75I); each S was run under all 4 conditions. Method Gaussian noise was presented binaurally in S's headphones throughout a test session and the signal was a 1000-cps sinusoid tone; the tone was presented for 100 msec. including equal fall and rise times of 20 msec. The ratio of signal energy to noise power in a unit bandwidth was 2.9, and was constant throughout the study. The. S was seated before a stimulus display board. On each trial a red warning light was flashed for 100 msec. Two amber lights then came on successively each for 1 sec.; these lights defined the 2 observation intervals. The onset of the signal occurred 500 msec. after the onset of one of the observation intervals. After the second amber light went off, S indicated his response by pressing 1 of 2 wand switches under cards reading "1st interval" and "2nd interval." For the !-condition a green light flashed on above the correct response key after S's response; the green light was omitted in the !-condition. Each trial lasted 6 sec. The S's were 12 male college students with normal hearing. They were run for two practice sessions followed by 20 test sessions. Test sessions were run on consecutive days, 350 trials/day. Each day S ran on 1 of the 4 experimental conditions; in successive 4-day blocks S ran one day on each of the 4 experimental conditions in a random order. Thus, over 20 days each of the experimental conditions was repeated 5 times

    New country and state records, and other notes for Mexican Buprestidae (Coleoptera)

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    Treatment is provided for 224 species and subspecies in the genera Acherusia, Acmaeodera, Actenodes, Agaeocera, Agrilus, Anthaxia, Brachys, Buprestis, Chalcangium, Chrysobothris, Colobogaster, Cyphothorax, Dicerca, Dismorpha, Euchroma, Hiperantha, Hylaeogena, Leiopleura, Lius, Mixochlorus, Omochyseus, Pachyschelus, Polycesta, Psiloptera, Spectralia, Taphrocerus, Tetragonoschema, Thrincopyge, Trypantius and Tyndaris. Of these, 44 are recorded for the first time from Mexico and 175 represent new state records. Adult host and/or habitat information is provided, usually from the label data, for 93 of the taxa. Larval host records are indicated for Chrysobothris analis LeConte, C. capitata Gory and Laporte, C. multistigmosa (Mannerheim) and C. sallei Waterhouse. Acmaeodera sinaloensis Duges has been discovered to breed in bamboo. A major taxonomic character of C. multistigmosa is discussed

    Ariel - Volume 4 Number 4

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    Editors David A. Jacoby Eugenia Miller Tom Williams Associate Editors Paul Bialas Terry Burt Michael Leo Gail Tenikat Editor Emeritus and Business Manager Richard J. Bonnano Movie Editor Robert Breckenridge Staff Richard Blutstein Mary F. Buechler Meg Brunt Steve Glinks Len Grasman Alice M. Johnson J.D. Kanofsky Tom Lehman Dave Mayer Bernie Odd

    Genomic and geographical structure of human cytomegalovirus

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    Human cytomegalovirus (CMV) has infected humans since the origin of our species and currently infects most of the world’s population. Variability between CMV genomes is the highest of any human herpesvirus, yet large portions of the genome are conserved. Here, we show that the genome encodes 74 regions of relatively high variability each with 2 to 8 alleles. We then identified two patterns in the CMV genome. Conserved parts of the genome and a minority (32) of variable regions show geographic population structure with evidence for African or European clustering, although hybrid strains are present. We find no evidence that geographic segregation has been driven by host immune pressure affecting known antigenic sites. Forty-two variable regions show no geographical structure, with similar allele distributions across different continental populations. These β€œnongeographical” regions are significantly enriched for genes encoding immunomodulatory functions suggesting a core functional importance. We hypothesize that at least two CMV founder populations account for the geographical differences that are largely seen in the conserved portions of the genome, although the timing of separation and direction of spread between the two are not clear. In contrast, the similar allele frequencies among 42 variable regions of the genome, irrespective of geographical origin, are indicative of a second evolutionary process, namely balancing selection that may preserve properties critical to CMV biological function. Given that genetic differences between CMVs are postulated to alter immunogenicity and potentially function, understanding these two evolutionary processes could contribute important information for the development of globally effective vaccines and the identification of novel drug targets

    Haplotype assignment of longitudinal viral deep-sequencing data using co-variation of variant frequencies

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    Longitudinal deep sequencing of viruses can provide detailed information about intra-host evolutionary dynamics including how viruses interact with and transmit between hosts. Many analyses require haplotype reconstruction, identifying which variants are co-located on the same genomic element. Most current methods to perform this reconstruction are based on a high density of variants and cannot perform this reconstruction for slowly evolving viruses. We present a new approach, HaROLD (HAplotype Reconstruction Of Longitudinal Deep sequencing data), which performs this reconstruction based on identifying co-varying variant frequencies using a probabilistic framework. We illustrate HaROLD on both RNA and DNA viruses with synthetic Illumina paired read data created from mixed human cytomegalovirus and norovirus genomes, and clinical datasets of human cytomegalovirus and norovirus samples, demonstrating high accuracy, especially when longitudinal samples are available

    Black carbon as an additional indicator of the adverse health effects of airborne particles compared with PM10 and PM2.5.

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    Current air quality standards for particulate matter (PM) use the PM mass concentration [PM with aerodynamic diameters ≀ 10 ΞΌm (PM(10)) or ≀ 2.5 ΞΌm (PM(2.5))] as a metric. It has been suggested that particles from combustion sources are more relevant to human health than are particles from other sources, but the impact of policies directed at reducing PM from combustion processes is usually relatively small when effects are estimated for a reduction in the total mass concentration
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