Low-profile helical array antenna fed from a radial waveguide

A low-profile array antenna composed of two-turn 4° pitch angle helices is designed for a frequency band of 11.7 GHz to 12.0 GHz. The feed wire of each helix is inserted into a radial waveguide through a small hole and excited by a traveling wave flowing in the transverse electromagnetic mode between the two parallel plates of the waveguide. The measured aperture efficiency shows a maximum value of 77% for a beam radiated in the normal direction and 69% for a 30° beam tilt     

Pitfalls and complications of colon interposition

Colon interposition is a complex operation that requires meticulous technique and attention to detail. In experienced hands, the colon is a valuable conduit for esophageal reconstruction, particularly in patients with benign disease.     

Compliance of secondary prophylaxis for controlling rheumatic fever and rheumatic heart disease in a rural area of northern India

Using the methods of recombination and gene disruption, the effects of degUS gene in Bacillus subtilis Ki-2-132 were studied. The results showed that the gene could affect all protease-producing, competence formation, cell mobility and repression effects of glucose on protease-production. This implies that it is a pleitropic gene in Bacillus subtilis Ki-2-132. The disruption of the gene caused morphological changes and repressed the expression of aprE in vectors.     

Dopamine infusion does not alter LH levels before or after chronic cocaine exposure in female rhesus monkeys

Cocaine stimulates release of luteinizing hormone (LH) in preclinical and clinical studies but the contribution of the indirect dopamine agonist actions of cocaine to its effects on LH are unclear. In the present study, we examined the effects of exogenous dopamine infusions on LH release in drug-naive, normally cycling, female rhesus monkeys. All studies were conducted during the mid-follicular phase (cycle days 6-8). Three successive 80-min dopamine infusions (10 micrograms/kg/min, intravenous) were alternated with 20- or 40-min interruptions of dopamine infusions. There were no significant changes in LH during or following dopamine infusions. Predopamine baseline LH levels averaged 30 +/- 5.4 ng/ml. LH averaged 31.7 +/- 1.3 ng/ml during dopamine infusions and 31.4 +/- 1.3 ng/ml after dopamine infusions stopped. To determine whether chronic cocaine exposure influenced the effect of dopamine on LH, rhesus females were studied after more than 2 years of cocaine self-administration at an average dose of 6.5 +/- 0.2 mg/kg/day. LH averaged 27.3 +/- 3.3 ng/ml during baseline and 26.9 +/- 0.7 ng/ml and 26.1 +/- 0.7 ng/ml during dopamine infusions and interruptions, respectively. Similarly, during withdrawal from cocaine, baseline LH levels averaged 32.1 +/- 4.5 ng/ml, and LH did not change significantly during dopamine infusions (31.2 +/- 1.1 ng/ml) and infusion interruptions (32.1 +/- 1.1 ng/ml). Under the conditions of the present study, dopamine administration did not change LH levels in gonadally intact rhesus monkeys, and these findings are consistent with previous studies in ovariectomized rhesus females. However, these data are not consistent with clinical reports, and some possible implications of this species difference are discussed. Moreover, these data suggest that the stimulation of LH by cocaine may not be explained by its indirect dopamine agonist actions.     

Relationship between grade and stage of renal pelvic and/or ureteral tumor and associated bladder tumor

The use of proxy respondents in surveys designed to provide population estimates of smoking prevalence offers an inexpensive way to obtain these data. The accuracy of this information is examined in analyzing data from tobacco use surveys of adults conducted in 22 North American communities as part of the National Cancer Institute's Community Intervention Trial for Smoking Cessation. Proxy-reported smoking status was obtained in a cross-sectional telephone survey conducted from August 1993 to January 1994 (n = 99,682). Self-reported smoking status was obtained from an in-depth interview of a sample of the respondents aged 25-64 years enumerated from the telephone survey (n = 31,417). Discrepancy rates were calculated by comparing the proxy-reported and self-reported smoking statuses of a given individual (n = 10,226). In both surveys, respondents were categorized as current smokers (those who currently smoke and have smoked at least 100 cigarettes in their lifetime), recent quitters (< or = 8 years since cessation), long-term quitters (> 8 years since cessation), and never smokers. The overall discrepancy rate between the self-report and the proxy report was 5.4%. Self-respondents who were black, Hispanic, Asian, recent quitters, or aged 25-34 years were more likely to have inconsistent proxy reports. The authors estimate that the screener interview underestimated the true smoking prevalence by 0.1% when they corrected for smoking status discrepancies. These results confirm that proxy-reported smoking status is an accurate and effective means to monitor populationwide smoking prevalence of adults.     

Sodium pump isoform specificity for the digitalis-like factor isolated from human peritoneal dialysate

We have isolated a labile, specific sodium pump inhibitor or digitalis-like factor from the peritoneal dialysate of volume-expanded renal failure patients whose levels correlated closely with volume status and blood pressure. This study characterizes the inhibitory profile of this agent compared with that of ouabain against the three alpha-isoforms of the sodium pump. We prepared microsomal Na,K-ATPase from rat tissues representing the highest proportion of one of the alpha-isoforms. Both Northern and Western blot analyses confirmed that kidney had predominantly the alpha1-isoform, skeletal muscle the alpha2-isoform, and fetal brain the alpha3-isoform. Ouabain (5 x 10(-6) mol/L) produced little inhibition of kidney Na,K-ATPase (3.4+/-2.0%) but significant inhibition of skeletal muscle (37.2+/-3.7%, P<.001) and fetal brain (38.8+/-3.5%, P<.001) activity. In contrast, the labile digitalis-like factor, causing comparable inhibition of fetal brain Na,K-ATPase activity (33.3+/-4.7%), produced markedly greater inhibition of kidney (42.5+/-5.6%, P<.001) and moderately greater inhibition of skeletal muscle pump activity (57.7+/-6.3%, P<.05). In addition, the labile digitalis-like factor produced a marked concentration-dependent inhibition of the alpha2- and alpha3-isoforms (r=.79, P=.00005). Experiments combining the labile digitalis-like factor and ouabain confirmed that digitalis-like factor, unlike ouabain, was an effective inhibitor of all three isoforms in rat, in particular alpha2. The different pattern of isoform sensitivity displayed by the labile digitalis-like factor and ouabain further differentiates the two agents and raises some interesting possibilities about the functional implications of the endogenous factor.     

Numerical simulation and PIV measurement of the flow-field in optical disc drives

A system of numerical flow simulation with an automated mesh generator and parallelized solver was developed and applied to the flow-field inside an optical disc drive. In this simulation system, a uniformly spaced Cartesian grid is used to reduce time and automatically generate a mesh from CAD data for complicated geometries, such as optical disc drives. The simulation results of optical disc drives are validated by particle image velocimetry (PIV) and pressure-distribution measurements. The measured velocity distributions above a rotating disc and around a pick-up unit show quantitative agreement with the simulated distributions. For the pressure distributions on a top case of an optical disc drive, although there is an error of 10% between simulated and measured results, the position of the peaks and distribution of pressure show good agreement. Comparing both sets of measurements, the simulation results in a Cartesian grid system are sufficiently accurate to enable the flow-field to be quantitatively assessed. This numerical flow simulation is applied to investigate the detailed flow-field in a commercial optical disc drive.