1,215 research outputs found
Lord of the Mood Rings
Our main objective is to study the mechanisms by which heat transfer taking place
in the human finger will affect the color change in the mood ring. This project uses
GAMBIT and FIDAP to model the heat transfer from the finger to the ring. Finding the
possible range of heat generations, one can estimate the temperature range of the surface
and thus the best type of LC to be used in a ring. By determining the temperature in the
ring at steady state the blood flow rate can be quantified, which will provide the required
heat generation to change the mood ring to any desired color. We obtained several Q?s
ranging from 6800 to 7200 W/m^3 appropriate to blood flow rate, and ambient conditions
with no forced convection for the model. Further sensitivity analysis was done for selected
data input, such as conductivity and source term, to assess their impact on the results. It
was concluded that blood flow rate corresponding to the heat generation values used
ranged from 0.245 to 0.265 cm^3/min. From the results it is recommended that the color
change in the LCD crystal should be most sensitive over the range of 32 to 35 ?C
Ferromagnetic properties of Zn1-xMnxO epitaxial thin films
We report on ferromagnetic characteristics of Zn1-xMnxO (x=0.1 and 0.3) thin films grown on Al2O3(00.1) substrates using laser molecular-beam epitaxy. By increasing the Mn content, the films exhibited increases in both the c-axis lattice constant and fundamental band gap energy. The Curie temperature obtained from temperature-dependent magnetization curves was 45 K for the film with x=0.3, depending on the Mn composition in the films. The remanent magnetization and coercive field of Zn0.9Mn0.1O at 5 K were 0.9 emu/g and 300 Oe, respectively. For Zn0.7Mn0.3O, the remanent magnetization at 5 K increased to 3.4 emu/g. (C) 2002 American Institute of Physics.open11509532sciescopu
Design, analysis, tools and applications for programmable high-speed and power-aware 4G processors
Data rate traffic and communication capacity demand have been increased continuously. Therefore, a highly advanced 4G wireless system is required to meet a high demand for modern mobile terminals. For getting a further improvement for 4G communication systems, new paradigms of design, analysis tools and applications for 4G communication processors are necessary. In this paper, some of these new paradigms are discussed. Furthermore, a single-step discrete cosine transform truncation (DCTT) method is proposed for the modeling-simulation in signal integrity verification for high-speed communication processors. ©2011 IEEE.published_or_final_versio
Association between Semen Exposure and Incident Bacterial Vaginosis
Objective. To identify correlates of incident bacterial vaginosis (BV) diagnosed with Nugent scoring among high-risk women.
Study Design. We conducted both cohort and case-crossover analyses, stratified by HIV infection status, based on 871 HIV-infected and 439 HIV-uninfected participants in the HIV Epidemiology Research Study, conducted in 4 US sites in 1993–2000. Results. BV incidence was 21% and 19% among HIV-infected and -uninfected women, respectively. Fewer correlates of BV were found with case-crossover than with cohort design. Reporting frequent coitus (regardless of consistency of condom use) was correlated with BV in cohort analyses but not in case-crossover analyses. The sole correlate of BV in both types of analyses was the detection of spermatozoa on Gram stain, which is a marker of semen exposure. Conclusion. The inconsistent association between condom use and BV in prior studies could be from reporting bias. We found evidence of a relationship between semen exposure and incident BV
Plasmonic excitations in noble metals: The case of Ag
The delicate interplay between plasmonic excitations and interband
transitions in noble metals is described by means of {\it ab initio}
calculations and a simple model in which the conduction electron plasmon is
coupled to the continuum of electron-hole pairs. Band structure effects,
specially the energy at which the excitation of the -like bands takes place,
determine the existence of a subthreshold plasmonic mode, which manifests
itself in Ag as a sharp resonance at 3.8 eV. However, such a resonance is not
observed in the other noble metals. Here, this different behavior is also
analyzed and an explanation is provided.Comment: 9 pages, 8 figure
Reduced Neutrophil Apoptosis in Diabetic Mice during Staphylococcal Infection Leads to Prolonged Tnfα Production and Reduced Neutrophil Clearance
Diabetes is a frequent underlying medical condition among individuals with Staphylococcus aureus infections, and diabetic patients often suffer from chronic inflammation and prolonged infections. Neutrophils are the most abundant inflammatory cells during the early stages of bacterial diseases, and previous studies have reported deficiencies in neutrophil function in diabetic hosts. We challenged age-matched hyperglycemic and normoglycemic NOD mice intraperitoneally with S. aureus and evaluated the fate of neutrophils recruited to the peritoneal cavity. Neutrophils were more abundant in the peritoneal fluids of infected diabetic mice by 48 h after bacterial inoculation, and they showed prolonged viability ex vivo compared to neutrophils from infected nondiabetic mice. These differences correlated with reduced apoptosis of neutrophils from diabetic mice and were dependent upon the presence of S. aureus and a functional neutrophil respiratory burst. Decreased apoptosis correlated with impaired clearance of neutrophils by macrophages both in vitro and in vivo and prolonged production of proinflammatory tumor necrosis factor alpha by neutrophils from diabetic mice. Our results suggest that defects in neutrophil apoptosis may contribute to the chronic inflammation and the inability to clear staphylococcal infections observed in diabetic patients
Diagnostic performance of contrast enhanced CT and 18F-FDG PET/CT in suspicious recurrence of biliary tract cancer after curative resection
<p>Abstract</p> <p>Background</p> <p>Because of the late clinical presentation of biliary tract cancer (BTC), only 10% of patients are eligible for curative surgery. Even among those patients who have undergone curative surgery, most patients develop recurrent cancer. This study is to determine the clinical role of <sup>18</sup>F-FDG PET/CT during post-operative surveillance of suspected recurrent BTC based on symptoms, laboratory findings and contrast-enhanced CT (ceCT) findings.</p> <p>Methods</p> <p>We consecutively enrolled 50 patients with BTC who underwent curative surgery. An <sup>18</sup>F-FDG PET/CT was obtained for assessment of recurrence based on clinical suspicion during post-operative surveillance. The final confirmation of recurrence was determined pathologically or clinically. When a pathologic confirmation was impossible or inconclusive, a clinical confirmation was used by radiologic correlation with subsequent follow-up ceCT at a minimum of 3-month intervals. Diagnostic efficacy was evaluated by comparing the results of ceCT and <sup>18</sup>F-FDG PET/CT with the final diagnosis.</p> <p>Results</p> <p>Among the 50 patients, 34(68%) were confirmed to have a recurrence. PET/CT showed higher sensitivity (88% <it>vs</it>. 76%, <it>p </it>= 0.16) and accuracy (82% <it>vs</it>. 66%, <it>p </it>= 0.11) for recurrence compared to ceCT, even though the difference was not significant. The positive (86% <it>vs</it>. 74%, <it>p </it>= 0.72) and negative predictive values for recurrence (73% <it>vs</it>. 47%, <it>p </it>= 0.55) were not significantly different between PET/CT and ceCT. However, an additional PET/CT on ceCT significantly improved the sensitivity than did a ceCT alone (94% [32/34] for PET/CT on ceCT <it>vs</it>. 76% [26/34] for ceCT alone, <it>p </it>= 0.03) without increasing the specificity, positive predictive value, and negative predictive value.</p> <p>Conclusions</p> <p><sup>18</sup>F-FDG PET/CT alone is not more sensitive or specific than ceCT in the detection of recurrent BTC after curative surgery. These results do not reach statistical significance, probably due to the low number of patients. However, an additional <sup>18</sup>F-FDG PET/CT on ceCT significantly improves the sensitivity of detecting recurrences.</p
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A Search for Dark Higgs Bosons
Recent astrophysical and terrestrial experiments have motivated the proposal
of a dark sector with GeV-scale gauge boson force carriers and new Higgs
bosons. We present a search for a dark Higgs boson using 516 fb-1 of data
collected with the BABAR detector. We do not observe a significant signal and
we set 90% confidence level upper limits on the product of the Standard
Model-dark sector mixing angle and the dark sector coupling constant.Comment: 7 pages, 5 postscript figures, published version with improved plots
for b/w printin
Distributed Stochastic Power Control in Ad-hoc Networks: A Nonconvex Case
Utility-based power allocation in wireless ad-hoc networks is inherently
nonconvex because of the global coupling induced by the co-channel
interference. To tackle this challenge, we first show that the globally optimal
point lies on the boundary of the feasible region, which is utilized as a basis
to transform the utility maximization problem into an equivalent max-min
problem with more structure. By using extended duality theory, penalty
multipliers are introduced for penalizing the constraint violations, and the
minimum weighted utility maximization problem is then decomposed into
subproblems for individual users to devise a distributed stochastic power
control algorithm, where each user stochastically adjusts its target utility to
improve the total utility by simulated annealing. The proposed distributed
power control algorithm can guarantee global optimality at the cost of slow
convergence due to simulated annealing involved in the global optimization. The
geometric cooling scheme and suitable penalty parameters are used to improve
the convergence rate. Next, by integrating the stochastic power control
approach with the back-pressure algorithm, we develop a joint scheduling and
power allocation policy to stabilize the queueing systems. Finally, we
generalize the above distributed power control algorithms to multicast
communications, and show their global optimality for multicast traffic.Comment: Contains 12 pages, 10 figures, and 2 tables; work submitted to IEEE
Transactions on Mobile Computin
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