Ornithine decarboxylase inactivation by putrescine: involvement of lipid peroxidation

Effect of polyamines on 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced reduction of lipid peroxidation was studied. Putrescine protected this lowering of lipid peroxidation in a concentration-dependent manner, but spermidine or spermine could not do so. Putrescine also inhibited the TPA-induced ornithine decarboxylase (ODC) activity and lowered the free sulfhydryl content of TPA exposed mouse skin. These observations indicate that putrescine inactivates ODC probably by lowering SH groups through lipid peroxidation.     

Fouling of RO membranes in wastewater applications

Organic and inorganic fouling problems associated with reverse osmosis treatment of municipal wastewater were studied at the Advanced Wastewater Treatment facilities at Hoover Dam. This study indicated that the severity of organic fouling can be reduced by improving the quality of the RO feedwater; namely, by removal of food sources for bacterial growth including BOD, TOC, and ammonia. This, besides the normal secondary treatment, required lime softening and filtration. Lime softening and filtration alone, without secondary treatment, were not found to be effective. Chlorination is necessary to discourage bacterial and fungal growth. Where dechlorination is required to protect the membrane, in the case of polyamide membranes for example, sodium bisulfite was found to be superior to sodium thiosulfate. Use of ultraviolet radiation showed promise as an alternate to chlorination for RO feedwater disinfection. Inorganic fouling can be controlled by pretreatment processes including softening and removal of iron and manganese, and by reducing water recovery.     

Synthesis and property evaluation of Y-Ba-Cu-O superconductors

Fine powders of yttrium, barium and copper oxide were synthesized by two different chemical precipitation methods using a spray atomizer. The average particle size in the sintered ceramic was in the range 1–2.5 microns and the superconducting transition temperature of different powders was in the range 60–90 K. With few exceptions, it was found that recalcination and annealing in oxygen will not improve the superconducting transition temperature.     

Buprenorphine-induced alterations of cocaine's reinforcing effects in rhesus monkey: a dose-response analysis

Buprenorphine reduces cocaine self-administration by rhesus monkeys, opiate- and cocaine-dependent men and polydrug abusers, but the mechanisms underlying these cocaine-opiate interactions are not well understood. In the present study, the effects of daily placebo or buprenorphine (0.1, 0.3 and 1.0 mg/kg) treatment on cocaine self-administration (0.001-0.3 mg/kg/inject) were examined in five cocaine-experienced rhesus monkeys. Saline and each of six cocaine doses were available in an irregular order. Responding for cocaine (or saline) and food was maintained on a second order FR4 (VR 16:5) schedule of reinforcement. During placebo treatment, the daily number of cocaine injections increased as the unit dose was increased and then decreased at higher doses. Cocaine doses that maintained the highest rates of responding during placebo treatment were more resistant to buprenorphine's effects. The typical increase in response rate during the first five cocaine injections of a session also was attenuated by buprenorphine. The ascending limb of the cocaine dose-response curve was shifted downward and approximately one log unit to the right during low-dose buprenorphine treatment (0.1 mg/kg/day). In contrast, individual response rates for food pellets were unaffected. We conclude that buprenorphine selectively decreases self-administration of some unit doses of cocaine at doses that have minimal effects on food-maintained responding.     

A high resolution electron spectrometer facility for studying the spectra of microscopically localized field emission sites on planar cathodes

A high resolution (?30 me V) electron spectrometer originally designed for studying micropoint emitters, has been adapted to measure the electron spectra of the microscopically localized field electron emission processes that occur on broad-area high voltage electrodes. Details are given of the redesigned electron optical and mechanical systems, including a new electrostatic interfacing lens and a micromanipulator assembly for scanning the specimen cathode. The performance of the new facility has been evaluated, and its resolution has been estimated to be <80 meV.A micropoint anode probe and an associated image intensifier viewing system has been used for recording the complementary electroluminescent optical emission spectra. Facilities for the in situ treatment of electrode surfaces, viz, electron bombardment heating and ion etching, have also been incorporated and their effect on the emission characteristics of broad-area sites has been investigated.