Gas transport in a model derived from Hansen-Ampaya anatomical data of the human lung

The anatomical data of the human lung published by Hansen and Ampaya are used in a model of gas transport in the lung. The Bohr dead space is calculated from solutions of a transport equation where diffusivity is given by an empirical formula obtained by Sherer et al. A satisfactory agreement is found with experimental data obtained from simultaneous washouts of H2 and SF6 for respiratory frequencies ranging between 15 and 60 min-1 and tidal volumes between 200 and 1,800 ml. The results support the idea that molecular diffusion is the main but not the only physical phenomenom which intervenes in gas mixing during breathing.     

Evolution of a state occupational lead exposure registry: 1986-1996

In the first 11 full years of operation (January 1, 1986, through December 31, 1996) of an adult lead registry in New Jersey, 23,456 reports of occupational lead toxicity (blood lead level > or = 1.21 mumol/L) in 4,011 workers, involving 496 workplaces, were received. The majority of the reports and workers were from the manufacturing and construction industries. Over the 11 years, the annual numbers of reports and workers declined, although the annual numbers of involved workplaces remained stable, as did the number of newly identified workers and workplaces. The decline occurred primarily in the manufacturing industry; the construction industry experienced an increase in reports and reported workers. For all years combined, 36% of reported workers had at least one blood lead level equal to or greater than 1.93 mumol/L, although in the most recent years the percentage dropped overall and in both the manufacturing and construction industries.     

Time resolved measurements by the pulse height analysis soft x-ray diagnostic on TCV

A single chord, single processing chain, hybrid (analog/digital) pulse height analysis diagnostic has been developed for the TCV tokamak, aiming to provide the evolution of the plasma electron temperature with a software selectable minimum temporal resolution of 100 ms. The high count rate (approximately 65 kHz) together with an energy resolution of 190 eV (at 5.9 keV) were achieved by encoding the data stream with an on-site developed interface amplifier and time generator. The diagnostic was also used to investigate the non-Maxwellian behavior of the electron energy distribution function with strong electron cyclotron resonance heating and to monitor the presence of intrinsic and injected impurities in the 700 eV-20 keV energy range. The conversion of this diagnostic into a real-time control tool is under development.     

底流消能的跌坎型消力池再附长度的试验研究

再附长度是衡量坎后底滚回流区水流特征的一个重要参数,再附长度随水流入射角度、跌坎深度的变化而变化。根据平面紊动射流理论,建立淹没紊动射流的扩散方程,推导出再附长度计算的半经验公式,并结合水力学试验,对公式进行验证。结果表明,通过试验观测所得观测值与通过半经验公式计算所得理论值吻合较好。     

Studies of prosody perception by cochlear implant patients

Prosodic information is conveyed to normally-hearing listeners by variations in acoustic fundamental frequency, amplitude envelope, and duration of speech segments. This study measured cochlear implant patients' sensitivity to these parameters in electrically coded speech. The psychophysical discrimination of electric parameters used to code prosodic information, were examined, together with prosody perception using speech processing strategies which modified the contributions of these parameters. Patients were implanted with the Cochlear Limited prosthesis and used the MPEAK speech processing strategy. In the psychophysical studies, difference limens were measured for steady-state and time-varying stimuli, of different pulse rates and pulse durations, over a series of different stimulus durations. These limens were obtained using an adaptive procedure which converged on the 50 per cent correct point. In the prosody perception studies, performance was measured for the MPEAK strategy and for strategies which modified the contributions of pulse rate and pulse duration. Data were collected for five tests of prosodic contrasts. Difference limens for steady-state pulse rates were larger at higher rates (17 per cent at 400 pulses/s) than at lower rates (6 per cent at 100 pulses/s). For some patients, limens for the time-varying pulse rates were larger than those for the steady-state pulse rates while for the other patients, the limens were similar. Difference limens for pulse duration were 0.3 dB, corresponding to 4 per cent of the dynamic range, for steady-state stimuli and doubled in size for the time-varying stimuli. Prosody perception performance was generally poorer for the modified strategies than for the MPEAK strategy, suggesting that the removal of information coded by pulse rate and pulse duration reduced the perception of prosodic contrasts.     

Case managed residential care for homeless addicted veterans. Results of a true experiment

There is an interesting relationship between the HIV virus, the health of the gastrointestinal tract, and AIDS wasting syndrome, involving Tumor Necrosis Factor alpha (TNF alpha), specific and non-specific immunity in the gut, gut permeability, and oxidative stress. It is hypothesized that the progression of HIV to full-blown AIDS may be impacted by maintaining a healthy gut. A therapeutic protocol which decreases oxidative stress, inhibits TNF alpha, enhances phase I and II liver detoxification, and improves specific and non-specific immunity in the gut should be part of a therapeutic protocol for HIV-infected individuals. Through a better understanding of the pathophysiology of HIV advancing to AIDS, the practitioner can develop a treatment strategy of nutritional and lifestyle changes which could theoretically prevent an HIV infection from advancing to full-blown AIDS.     

Health services research clinical trials: issues in the evaluation of economic costs and benefits

The endoplasmic reticulum chaperone glucose-regulated protein 78 (GRP78) is essential for the proper glycosylation, folding and assembly of many membrane bound and secreted proteins. GRP78 mRNA is well known to be induced in cultured cells by lowering medium glucose concentrations from 4.5 to 0 mg/ml. Here we report a study designed to determine the effects of intermediate concentrations of glucose on GRP78 mRNA abundance. Progressive reduction in culture medium glucose from 4.5 to 1.0 mg/ml progressively reduced GRP78 mRNA to approximately 30% of the initial level. Induction of GRP78 mRNA by glucose starvation was observed in medium containing less than 1 mg/ml glucose. Determination of the amount of glucose consumed in these cultures showed that reduction of glucose concentrations led first to repression of GRP78 mRNA abundance, followed by induction of the mRNA only when glucose is nearly exhausted. Caloric restriction in mice both reduces fasting and mean 24 h glucose blood concentrations and GRP78 mRNA abundance in the liver. Thus, it is possible that negative regulation of GRP78 mRNA in the liver is due directly to reduced blood glucose concentrations.