New high-rate dry etch mixture for INP-based heterostructures

A dry etch mixture based on HI/H/sub 2/ is shown to provide smooth, equirate removal of InP and InGaAsP at rates of approximately 2000 AA min/sup -1/ even for very low (-100 V) DC biases on the sample. This is significantly faster than the rates obtained with the more conventional CH/sub 4//H/sub 2/ mixtures commonly used for dry etching of InP-based heterostructures. Metal masks (Ni, Pt, Mo, Ti and Al) show minimal erosion during exposure to HI/H/sub 2/ discharges, and other common masking materials (Au, SiO/sub 2/) also show very low removal rates (<20 AA min/sup -1/) for low (>     

Studies on the hypocalcemic actions of salmon calcitonin and ultimobranchial gland extracts in the freshwater teleost Cyprinus carpio

The equatorial current of the frog lens was studied with microelectrodes and a vibrating probe. Norepinephrine, isoproterenol and terbutaline applied topically at the surface of the cornea as a 1% solution increased the equatorial current of the lens about 80%. This increase was blocked by timolol. Topical forskolin increased the equatorial current by over 80%. This effect of forskolin was not blocked by timolol. These substances did not affect the equatorial current of the lens when the lens was suspended in a frog Ringers solution. 8-Bromo cyclic AMP increased the equatorial current when it was applied topically but not when it was added directly to the medium bathing an isolated lens. The results suggest that beta-adrenergic agonists, applied topically to the cornea, increase the equatorial current of the lens by a mechanism that is mediated by cyclic AMP. The finding that 8-bromo cyclic AMP did not act directly on the lens suggests that a currently unknown substance or process is active at the level of the lens.     

Quantitative bacillary response to treatment in HIV-associated pulmonary tuberculosis

A group of 122 patients with culture-proven pulmonary tuberculosis were recruited to examine the concentrations of Mycobacterium tuberculosis in sputum and the relationship to HIV-1 antibody status. They were followed for up to 28 days from the start of antituberculous chemotherapy to assess the early bacillary response to two chemotherapeutic regimens. Of 67 treated with streptomycin, thiacetazone, and isoniazid 17 were HIV positive, and subsequently 55, of whom 20 were HIV positive, were treated with streptomycin, rifampin, isoniazid, and pyrazinamide. The mean initial concentration of M. tuberculosis in the sputum of the HIV-negative patients was significantly higher than in HIV-positive patients (6.95 and 6.34 log colony-forming units respectively; p = 0.019). The HIV-positive patients had less radiologic evidence of disease and significantly fewer zones of lung affected with cavities. The response to treatment was similar, but with HIV-positive patients more likely to become culture negative by 28 days. The differences that exist between HIV-positive and HIV-negative patients are minor, and standard regimens are at least as effective in HIV-positive patients in the first month of treatment.     

Cemented acetabular reconstruction with the Müller support ring. A minimum five-year clinical and roentgenographic follow-up study

In a previous study, the results of cemented acetabular reconstruction with a Müller support ring were reported after a mean follow-up period of 40 months. The current report concerns a minimum five-year follow-up study of the same 43 patients. Two early failures at four months and at 17 months were related to poor surgical technique. The latest overall functional results, according to the Merle d'Aubigné rating scale, were excellent, very good, or good in 81.82% of the hips: a drop from 86.67% since the previous report. Sequential roentgenographic analysis demonstrated a high incidence of nonprogressive radiolucencies at the cement-bone interface. These nonprogressive radiolucencies did not correlate with the overall functional results. The progression of a radiolucency at the cement-bone interface, however, or the appearance of radiolucencies around the screw threads, always resulted in clinical failure.