589 research outputs found
Textile Diamond Dipole and Artificial Magnetic Conductor Performance under Bending, Wetness and Specific Absorption Rate Measurements
Textile diamond dipole and Artificial Magnetic Conductor (AMC) have been proposed and tested under wearable and body centric measurements. The proposed antenna and AMC sheet are entirely made of textiles for both the substrate and conducting parts, thus making it suitable for wearable communications. Directive radiation patterns with high gain are obtained with the proposed AMC sheet, hence minimizing the radiation towards the human body. In this study, wearable and body centric measurements are investigated which include bending, wetness and Specific Absorption Rate (SAR). Bending is found not to give significant effect to the antenna and AMC performance, as opposed to wetness that yields severe performance distortion. However, the original performance is retrieved once the antenna and AMC dried. Moreover, notable SAR reduction is achieved with the introduction of the AMC sheet, which is appropriate to reduce the radiation that penetrates into human flesh
Textile diamond dipoles for body centric communications at 2.45GHZ and 5.8GHZ
This study proposes textile diamond dipoles for body centric communication that operate at 2.45GHz and 5.8GHz. The proposed antennas have been rigorously tested under wearable and body centric measurements. Both substrates and conducting parts of the diamond dipoles are entirely made of textiles; which is deemed fit for wearable communications. Experiments such as bending, wetness and SAR were performed to investigate the antennas' performance for body communication realization. Bending was found not to cause any significant performance disruption. On the other hand, since the proposed antenna is not made of water-proof material, the performance was distorted under wet condition. However, once the antenna was dried out, the original performance was achieved. SAR measurement was also conducted and significant SAR values were observed when placing the proposed diamond dipoles close to human body
A parametric study of textile artificial magnetic conductor with wire dipole at 2.45GHZ and 5.8GHZ
Textile Artificial Magnetic Conductor (AMC) with wire dipole is presented. The AMCs are made of fleece and Shieldit fabrics and were designed to have in-phase reflections at 2.45GHz and 5.8GHz. Thorough parametric studies based on AMC unit cell have been performed to obtain the optimized design. Performance comparison between different types of environments, fabrics and arrays size were also conducted. The proposed AMC and wire dipole are designed, simulated, fabricated and tested. Results of return loss, radiation pattern and gain are presented. Results show that forward directive radiation pattern with improved gain are achieved with the introduction of the AMC at both 2.45GHz and 5.8GHz. The proposed textile AMC is suitable for body centric communication systems
Early-life Risk Factors for Adult Chronic Disease: Follow-up of a Cohort Born During 1964–1978 in an Urban Slum of Lahore, Pakistan
Evidence suggests that risk of chronic diseases may be programmed during the foetal and early life of the infant. With high rates of low birthweight coupled with a rapid nutritional transition, low-income countries are facing an epidemic of chronic diseases. Follow-up of a cohort of adults born during 1964–1978 in an urban slum in Lahore, Pakistan, is presented in this paper. In 695 of these adults (mean age=29.0 years, males=56%), blood pressure, fasting blood glucose, and body mass index (BMI) were measured to assess early-life predictors of risk of chronic diseases. Sixteen percent of the study population was born with a low birthweight (<2,500 g). A significant positive association (p=0.007) was observed between birthweight and BMI; additionally, adjusting for age and gender, the association with BMI was highly significant (p=0.000). Conversely, a significant negative association (p=0.016) was observed between birthweight and adult levels of fasting plasma glucose; after adjustment for age and gender, the association was more significant (p=0.005) No association was observed between birthweight and adult blood pressure. The results suggest that low birthweight may increase later risk of impaired glucose tolerance in urban Pakistani adults. Further research in this area is warranted
Detrimental effects of tropisetron on permanent ischemic stroke in the rat
<p>Abstract</p> <p>Background</p> <p>Recent <it>in vitro </it>evidence indicates that blockade of 5-hydroxytryptamine (5-HT) receptor 3 (5-HT<sub>3</sub>) is able to confer protection in different models of neuronal injury. The purpose of the present study was to investigate the effect of tropisetron, a 5-HT<sub>3 </sub>receptor antagonist, on infarct size and neurological score in a model of ischemic stroke induced by permanent middle cerebral artery occlusion (pMCAO) in the rat.</p> <p>Methods</p> <p>Two different doses of tropisetron (5 and 10 mg/kg) or vehicle were administered intraperitoneally 30 min before pMCAO. Neurological deficit scores, mortality rate and infarct volume were determined 24 h after permanent focal cerebral ischemia.</p> <p>Results</p> <p>Tropisetron failed to reduce cerebral infarction. Animals receiving tropisetron showed a significant increase (p < 0.05) in neurological deficits and mortality rate.</p> <p>Conclusion</p> <p>Data from this study indicate that blockade of 5-HT<sub>3 </sub>receptors with tropisetron worsens ischemic brain injury induced by pMCAO. These findings could have important clinical implications. Patients taking tropisetron, and possibly other 5-HT<sub>3 </sub>antagonists, could potentially have a worse outcome following a brain infarct.</p
Nuclear Transparency to Intermediate-Energy Protons
Nuclear transparency in the (e,e'p) reaction for 135 < Tp < 800 MeV is
investigated using the distorted wave approximation. Calculations using
density-dependent effective interactions are compared with phenomenological
optical potentials. Nuclear transparency is well correlated with proton
absorption and neutron total cross sections. For Tp < 300 MeV there is
considerable sensitivity to the choice of optical model, with the empirical
effective interaction providing the best agreement with transparency data. For
Tp > 300 MeV there is much less difference between optical models, but the
calculations substantially underpredict transparency data and the discrepancy
increases with A. The differences between Glauber and optical model
calculations are related to their respective definitions of the semi-inclusive
cross section. By using a more inclusive summation over final states the
Glauber model emphasizes nucleon-nucleon inelasticity, whereas with a more
restrictive summation the optical model emphasizes nucleon-nucleus
inelasticity; experimental definitions of the semi-inclusive cross section lie
between these extremes.Comment: uuencoded gz-compressed tar file containing revtex and bbl files and
5 postscript figures, totalling 31 pages. Uses psfi
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