12,984 research outputs found
CCAAT/Enhancer Binding Proteins Are Not Required for HIV-1 Entry but Regulate Proviral Transcription by Recruiting Coactivators to the Long-Terminal Repeat in Monocytic Cells
AbstractCCAAT/enhancer binding proteins (C/EBP) have been shown to be required for HIV-1 transcription and replication in macrophages. However, whether these transcription factors influence the ability of virus to establish infection by altering cytokine or receptor expression or primarily regulate HIV-1 transcription has not been determined. By inhibiting endogenous C/EBP activity with a dominant-negative protein, we demonstrate that functional C/EBPs are not required for HIV-1 infection and that these factors influence replication by a transcriptional mechanism. C/EBPβ recruits coactivators to the HIV-1 long-terminal repeat (LTR) and physically interacts with histone acetyltransferase (HAT) complexes, suggesting that C/EBPs participate in remodeling the chromatin organization of the HIV-1 provirus. Furthermore, overexpression of a C/EBP dominant-negative inhibits displacement of nucleosomes located at the HIV-1 transcriptional start site. These results provide insight into the general mechanisms by which C/EBPs regulate macrophage-restricted HIV-1 transcription
The Effects of a High Fat Meal on Blood Flow Regulation during Arm Exercise
A diet high in saturated fats results in endothelial dysfunction and can lead to atherosclerosis, a precursor to cardiovascular disease. Exercise training is a potent stimulus though to mitigate the negative effects of a high saturated fat diet; however, it is unclear how high-saturated fat meal (HSFM) consumption impacts blood flow regulation during a single exercise session.
PURPOSE: This study sought to examine the impact of a single HSFM on peripheral vascular function during an acute upper limb exercise bout.
METHODS: Ten young healthy individuals completed two sessions of progressive handgrip exercise. Subjects either consumed a HSFM (0.84 g of fat/kg of body weight) 4 hours prior or remained fasted before the exercise bout. Progressive rhythmic handgrip exercise (6kg, 12kg, 18kg) was performed for 3 minutes per stage at rate of 1 Hz. The brachial artery (BA) diameter and blood velocity was obtained using Doppler Ultrasound (GE Logiq e) and BA blood flow was calculated with these values.
RESULTS: BA blood flow and flow mediated dilation (normalized for shear rate) during the handgrip exercise significant increased from baseline in all workloads, but no differences were revealed in response to the HSFM consumption.
CONCLUSION: Progressive handgrip exercise augmented BA blood flow and flow mediated dilation in both testing days; however, there was no significant differences following the HSFM consumption. This suggests that upper limb blood flow regulation during exercise is unaltered by a high fat meal in young healthy individuals.https://scholarscompass.vcu.edu/gradposters/1060/thumbnail.jp
KMT-2016-BLG-2052L: Microlensing Binary Composed of M Dwarfs Revealed from a Very Long Time-scale Event
We present the analysis of a binary microlensing event KMT-2016-BLG-2052, for
which the lensing-induced brightening of the source star lasted for 2 seasons.
We determine the lens mass from the combined measurements of the microlens
parallax \pie and angular Einstein radius \thetae. The measured mass
indicates that the lens is a binary composed of M dwarfs with masses of
and . The measured relative
lens-source proper motion of is smaller
than of typical Galactic lensing events, while
the estimated angular Einstein radius of \thetae\sim 1.2~{\rm mas} is
substantially greater than the typical value of .
Therefore, it turns out that the long time scale of the event is caused by the
combination of the slow and large \thetae rather than the heavy mass of
the lens. From the simulation of Galactic lensing events with very long time
scales ( days), we find that the probabilities that long
time-scale events are produced by lenses with masses and
are and 2.6\%, respectively, indicating that
events produced by heavy lenses comprise a minor fraction of long time-scale
events. The results indicate that it is essential to determine lens masses by
measuring both \pie and \thetae in order to firmly identify heavy stellar
remnants such as neutron stars and black holes.Comment: 9 pages, 11 figure
Fractional flow reserve vs. angiography in guiding management to optimize outcomes in non-ST-segment elevation myocardial infarction: the British Heart Foundation FAMOUS-NSTEMI randomized trial
Aim: We assessed the management and outcomes of non-ST segment elevation myocardial infarction (NSTEMI) patients randomly assigned to fractional flow reserve (FFR)-guided management or angiography-guided standard care.
Methods and results: We conducted a prospective, multicentre, parallel group, 1 : 1 randomized, controlled trial in 350 NSTEMI patients with ≥ coronary stenosis ≥30% of the lumen diameter assessed visually (threshold for FFR measurement) (NCT01764334). Enrolment took place in six UK hospitals from October 2011 to May 2013. Fractional flow reserve was disclosed to the operator in the FFR-guided group (n = 176). Fractional flow reserve was measured but not disclosed in the angiography-guided group (n = 174). Fractional flow reserve ≤0.80 was an indication for revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG). The median (IQR) time from the index episode of myocardial ischaemia to angiography was 3 (2, 5) days. For the primary outcome, the proportion of patients treated initially by medical therapy was higher in the FFR-guided group than in the angiography-guided group [40 (22.7%) vs. 23 (13.2%), difference 95% (95% CI: 1.4%, 17.7%), P = 0.022]. Fractional flow reserve disclosure resulted in a change in treatment between medical therapy, PCI or CABG in 38 (21.6%) patients. At 12 months, revascularization remained lower in the FFR-guided group [79.0 vs. 86.8%, difference 7.8% (−0.2%, 15.8%), P = 0.054]. There were no statistically significant differences in health outcomes and quality of life between the groups.
Conclusion: In NSTEMI patients, angiography-guided management was associated with higher rates of coronary revascularization compared with FFR-guided management. A larger trial is necessary to assess health outcomes and cost-effectiveness
OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected From Spitzer Only
We analyze the binary gravitational microlensing event OGLE-2017-BLG-1130
(mass ratio q~0.45), the first published case in which the binary anomaly was
only detected by the Spitzer Space Telescope. This event provides strong
evidence that some binary signals can be missed by observations from the ground
alone but detected by Spitzer. We therefore invert the normal procedure, first
finding the lens parameters by fitting the space-based data and then measuring
the microlensing parallax using ground-based observations. We also show that
the normal four-fold space-based degeneracy in the single-lens case can become
a weak eight-fold degeneracy in binary-lens events. Although this degeneracy is
resolved in event OGLE-2017-BLG-1130, it might persist in other events.Comment: 14 pages, 5 figure
Active cooling control of the CLEO detector using a hydrocarbon coolant farm
We describe a novel approach to particle-detector cooling in which a modular
farm of active coolant-control platforms provides independent and regulated
heat removal from four recently upgraded subsystems of the CLEO detector: the
ring-imaging Cherenkov detector, the drift chamber, the silicon vertex
detector, and the beryllium beam pipe. We report on several aspects of the
system: the suitability of using the aliphatic-hydrocarbon solvent PF(TM)-200IG
as a heat-transfer fluid, the sensor elements and the mechanical design of the
farm platforms, a control system that is founded upon a commercial programmable
logic controller employed in industrial process-control applications, and a
diagnostic system based on virtual instrumentation. We summarize the system's
performance and point out the potential application of the design to future
high-energy physics apparatus.Comment: 21 pages, LaTeX, 5 PostScript figures; version accepted for
publication in Nuclear Instruments and Methods in Physics Research
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