494 research outputs found
Radial optical emission profiles of radio frequency glow discharges
Radial optical emission profiles are determined from Abel inverted emission spectroscopy of a parallel plate radio frequency system known as a GEC Reference Cell. These profiles in general show a nonuniform plasma, annular in shape. Etching results of silicon wafers also follow this annular pattern. This effect is explained by numerically computed large radial and axial electric fields near the edge of the electrodes, produced by the presence of the grounded dark shields.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71294/2/JAPIAU-74-5-3590-1.pd
EGF regulates survivin stability through the Raf-1/ERK pathway in insulin-secreting pancreatic β-cells
<p>Abstract</p> <p>Background</p> <p>Postnatal expansion of the pancreatic β-cell mass is required to maintain glucose homeostasis immediately after birth. This β-cell expansion is regulated by multiple growth factors, including glucose, insulin, insulin-like growth factor (IGF-1) and epidermal growth factor (EGF). These mitogens signal through several downstream pathways (AKT, ERK, STAT3, and JNK) to regulate the survival and proliferation of β-cells. Survivin, an oncofetal protein with both pro-proliferative and anti-apoptotic properties, is a known transcriptional target of both IGF-1 and EGF in cancer cells. Here, we analyzed the effects of the β-cell mitogens IGF-1 and EGF on survivin regulation in the established pancreatic β-cell model cell lines, MIN6 and INS-1 and in primary mouse islets.</p> <p>Results</p> <p>In pancreatic β-cells, treatment with glucose, insulin, or EGF increased survivin protein levels at early time points. By contrast, no significant effects on survivin were observed following IGF-1 treatment. EGF-stimulated increases in survivin protein were abrogated in the presence of downstream inhibitors of the Raf-1/MEK/ERK pathway. EGF had no significant effect on <it>survivin </it>transcription however it prolonged the half-life of the survivin protein and stabilized survivin protein levels by inhibiting surviving ubiquitination.</p> <p>Conclusions</p> <p>This study defines a novel mechanism of survivin regulation by EGF through the Raf-1/MEK/ERK pathway in pancreatic β-cells, via prolongation of survivin protein half-life and inhibition of the ubiquitin-mediated proteasomal degradation pathway. This mechanism may be important for regulating β-cell expansion after birth.</p
Validation of a Multivariate Serum Profile for Epithelial Ovarian Cancer Using a Prospective Multi-Site Collection
In previous studies we described the use of a retrospective collection of ovarian cancer and benign disease samples, in combination with a large set of multiplexed immunoassays and a multivariate pattern recognition algorithm, to develop an 11-biomarker classification profile that is predictive for the presence of epithelial ovarian cancer. In this study, customized, Luminex-based multiplexed immunoassay kits were GMP-manufactured and the classification profile was refined from 11 to 8 biomarkers (CA-125, epidermal growth factor receptor, CA 19-9, C-reactive protein, tenascin C, apolipoprotein AI, apolipoprotein CIII, and myoglobin). The customized kits and the 8-biomarker profile were then validated in a double-blinded manner using prospective samples collected from women scheduled for surgery, with a gynecologic oncologist, for suspicion of having ovarian cancer. The performance observed in model development held in validation, demonstrating 81.1% sensitivity (95% CI 72.6 – 87.9%) for invasive epithelial ovarian cancer and 85.4% specificity (95% CI 81.1 – 88.9%) for benign ovarian conditions. The specificity for normal healthy women was 95.6% (95% CI 83.6 – 99.2%). These results have encouraged us to undertake a second validation study arm, currently in progress, to examine the performance of the 8-biomarker profile on the population of women not under the surgical care of a gynecologic oncologist
NASA Goddard Space Flight Center's Compendium of Recent Single Event Effects Results
We present the results of single event effects (SEE) testing and analysis investigating the effects of radiation on electronics. This paper is a summary of test results
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Surface and Lightning Sources of Nitrogen Oxides over the United States: Magnitudes, Chemical Evolution, and Outflow
We use observations from two aircraft during the ICARTT campaign over the eastern United States and North Atlantic during summer 2004, interpreted with a global 3-D model of tropospheric chemistry (GEOS-Chem) to test current understanding of regional sources, chemical evolution, and export of NOx. The boundary layer NOx data provide top-down verification of a 50% decrease in power plant and industry NOx emissions over the eastern United States between 1999 and 2004. Observed NOx concentrations at 8–12 km altitude were 0.55 ± 0.36 ppbv, much larger than in previous U.S. aircraft campaigns (ELCHEM, SUCCESS, SONEX) though consistent with data from the NOXAR program aboard commercial aircraft. We show that regional lightning is the dominant source of this upper tropospheric NOx and increases upper tropospheric ozone by 10 ppbv. Simulating ICARTT upper tropospheric NOx observations with GEOS-Chem requires a factor of 4 increase in modeled NOx yield per flash (to 500 mol/flash). Observed OH concentrations were a factor of 2 lower than can be explained from current photochemical models, for reasons that are unclear. A NOy-CO correlation analysis of the fraction f of North American NOx emissions vented to the free troposphere as NOy (sum of NOx and its oxidation products) shows observed f = 16 ± 10% and modeled f = 14 ± 9%, consistent with previous studies. Export to the lower free troposphere is mostly HNO3 but at higher altitudes is mostly PAN. The model successfully simulates NOy export efficiency and speciation, supporting previous model estimates of a large U.S. anthropogenic contribution to global tropospheric ozone through PAN export.Earth and Planetary SciencesEngineering and Applied Science
Real-Time Reverse Transcription–Polymerase Chain Reaction Assay for SARS-associated Coronavirus
A real-time reverse transcription–polymerase chain reaction (RT-PCR) assay was developed to rapidly detect the severe acute respiratory syndrome–associated coronavirus (SARS-CoV). The assay, based on multiple primer and probe sets located in different regions of the SARS-CoV genome, could discriminate SARS-CoV from other human and animal coronaviruses with a potential detection limit of <10 genomic copies per reaction. The real-time RT-PCR assay was more sensitive than a conventional RT-PCR assay or culture isolation and proved suitable to detect SARS-CoV in clinical specimens. Application of this assay will aid in diagnosing SARS-CoV infection
An Unusual Radio Galaxy in Abell 428: A Large, Powerful FR I Source in a Disk-Dominated Host
We report the discovery of a powerful (~10^{24} Watts/Hz) FR I radio source
in a highly flattened disk-dominated galaxy. Half of the radio flux from this
source is concentrated within the host galaxy, with the remainder in a pair of
nearly symmetrical lobes with total extent ~200kpc nearly perpendicular to the
disk. The traditional wisdom maintains that powerful, extended radio sources
are found only in ellipticals or recent merger events. We report B,R,J, and K
imaging, optical spectroscopy, a rotation curve, an IRAS detection, and a VLA
20cm image for this galaxy, 0313-192. The optical and NIR images clearly show a
disk. We detect apparent spiral arms and a dust-lane from B band imaging. The
reddened nucleus is consistent with extinction by a similar dust-lane. The
optical spectrum suggests a central AGN and some evidence of a starburst, with
both the AGN and central starlight appearing substantially reddened. From
analysis of the extended line emission in [OIII] and H-alpha we derive a
rotation curve consistent with an early- type, dusty spiral seen edge-on. From
the IRAS detection at 60 and 100 microns, we find that the ratio of Far IR to
radio flux places this object firmly as a radio galaxy (i.e. the radio emission
is not powered by star formation). The radio structure suggests that the radio
source in this galaxy is related to the same physical mechanisms present in
jet-fed powerful radio sources, and that such powerful, extended sources can
(albeit extremely rarely) occur in a disk-dominated host.Comment: 30 pages LaTeX, 1 table, 8 postscript figures. Accepted for
publication in the Astrophysical Journa
Smc5/6 coordinates formation and resolution of joint molecules with chromosome morphology to ensure meiotic divisions
During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4Eme1. Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastroph
Infographic. Clinical recommendations for return to play during the COVID-19 pandemic
COVID-19 AND RETURN TO PLAY
The world of sport has recently returned to training and competition following suspension due to the COVID-19 pandemic. It is concerning that a number of athletes have tested positive for COVID-19 after returning to competition. 1 Numerous authors have attempted to address return to play given the importance and complexity of the issue, with notable attention on possible cardiac implications.2–6
SCOPE OF THE INFOGRAPHIC
The specific recommendations shown in the present infographic (figure 1) have been generated by a panel of international experts and represent a compilation of the numerous approaches used to inform resumption of regular sports during the COVID-19 pandemic. Despite the different regulations around the world and the particular characteristics of each sport, it is essential to provide informative, consistent and specific guidance for safe return to training and competition at this most difficult time. ..
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