Electrodermal level asymmetry in a unilateral brain-damaged patient

To compare the effectiveness of various sperm preparation methods, we examined sperm concentration, percentage of progressive motility, recovery rate, and various motion characteristics in 32 semen samples after Percoll and IxaPrep preparations. Except for sperm concentration, which was much higher after IxaPrep preparation, no statistical differences existed between these two methods in terms of motile sperm concentration (MSC), recovery rate, mean curvilinear velocity (VCL), mean straight-line velocity (VSL) and mean amplitude of lateral head displacement (ALH). Among 22 samples that were allocated in a 37 degrees C, 5% CO2 incubator, the mean MSC after 3 hours was significantly higher following IxaPrep preparation than following Percoll preparation (63.2 x 10(6)/mL vs. 42.8 x 10(6)/mL, p < .03). VCL and VSL were much higher after IxaPrep preparation than after Percoll preparation, both at 3 hours (p < .01) and at 24 hours (p < .03). ALH was also higher after IxaPrep preparation than after Percoll preparation, and it was statistically significant after 3 hours of incubation (p < .03). We conclude that the IxaPrep gradient may be adopted as the preferred method to the Percoll gradient in preparing spermatozoa for assisted reproduction because of the spermatozoa's persistent and better motion activities after incubation.     

Photoinduced oxidation of Hg0(aq) in the waters from the St. Lawrence estuary

The oxidation of volatile aqueous Hg0 in aquatic systems may be important in decreasing the fluxes of Hg out of the water column. Using incubations of natural samples from the St. Lawrence River, we examined some of the parameters that control this oxidation. Hg0 was found to be chiefly mediated by UV radiation since (i) "dark" oxidation was not found to be statistically significant; (ii) visible light induced a significant but slow photooxidation (k = 0.09 h(-1)); and (iii) visible + UV radiation led to a faster photooxidation (k = 0.6-0.7 h(-1)), mainly because of UV-A induced reactions. Doubling UV irradiation did not increase the reaction rate of Hg0 photooxidation in natural water samples, indicating that some factor other than photon flux was rate limiting and suggesting that the reaction involves intermediate photoproduced oxidant(s). The addition of methanol, a *OH scavenger, decreased Hg photooxidation rates by 25% in brackish waters and by 19% in artificial saline water containing semiquinones, indicating that *OH may be partly responsible for Hg0 oxidation. Photooxidation rates were not affected by oxygen concentrations and did not decrease when samples were heat-sterilized, treated with chloroform, or filtered prior to exposure to light.     

Temperature effects on in vitro lipid accumulation in asexual embryos ofTheobroma cacao L.

Asexual embryos of cacao were grown for 40–50 days in a modified Murashige and Skoog liquid medium with sucrose concentration increased stepwise from 3 to 27% at temperatures of 10, 17, 20, 23, 26, 29, 32 or 35 C. Temperature influenced overall embryo growth as well as lipid accumulation and composition. Maximum growth occurred at 29 C, whereas maximum lipid and fatty acid accumulation occurred at 26 C. The proportion of individual fatty acids as total fatty acids accumulated per asexual embryo was constant at each temperature but varied with temperature from 10 to 35 C. The fatty acid composition of asexual embryos grown at 26 C was the most similar to that of cocoa butter, the lipid from mature zygotic embryos produced in vivo.     

The role of mercury redox reactions in snow on snow-to-air mercury transfer

Wet deposition of Hg in snow represents a major air-to-land flux of Hg in temperate and polar environments. However, the chemical speciation of Hg in snow and its chemical and physical behavior after deposition are poorly understood. To investigate Hg dynamics in snow, we followed Hg0 and total Hg concentrations in a snowpack above a frozen lake over 1 month. Our results indicate that newly deposited Hg is highly labile in snowpacks. On average, Hg levels in particular snow episodes decrease by 54% within 24 h after deposition. We hypothesize that Hg depletion in snow could be caused by a rapid snow-to-air Hg transfer resulting from Hg(II) photoinduced reduction to volatile Hg0. Both snowmelt incubated under a UV lamp at 17 degrees C and solid snow incubated under the sun at -10 degrees C in clear reaction vessels yielded a statistically significant increase in Hg0(aq) with time of exposure, while the Hg0(aq) levels remained constant in the dark controls. The snow-to-air Hg transfer we observed in this study suggests that the massive Hg deposition events observed in springtime in northern environments may have less impact than previously anticipated, since once deposited, Hg could be rapidly reduced and re-emitted.     

Deficit irrigation of a landscape halophyte for reuse of saline waste water in a desert city

Saline waste waters from industrial and water treatment processes are an under-utilized resource in desert urban environments. Management practices to safely use these water sources are still in development. We used a deeprooted native halophyte, Atriplex lentiformis (quailbush), to absorb mildly saline effluent (1800 mg l^?1 total dissolved solids, mainly sodium sulfate) from a water treatment plant in the desert community of Twentynine Palms, California. We developed a deficit irrigation strategy to avoid discharging water past the root zone to the aquifer. The plants were irrigated at about one-third the rate of reference evapotranspiration (ET_o) calculated from meteorological data over five years and soil moisture levels were monitored to a soil depth of 4.7 m at monthly intervals with a neutron hydroprobe. The deficit irrigation schedule maintained the soil below field capacity throughout the study. Water was presented on a more or less constant schedule, so that the application rates were less than ET_o in summer and equal to or slightly greater than ET_o in winter, but the plants were able to consume water stored in the profile in winter to support summer ET. Sodium salts gradually increased in the soil profile over the study but sulfate levels remained low, due to formation of gypsum in the calcic soil. The high salt tolerance, deep roots, and drought tolerance of desert halophytes such as A. lentiformis lend these plants to use as deficit-irrigated landscape plants for disposal of effluents in urban setting when protection of the aquifer is important.     

Accumulation of lipids,proteins, alkaloids and anthocyanins during embryo development in vivo ofTheobroma cacao L.

Developing embryos ofTheobroma cacao ranging in weight from 0.01–2.2 g dry weight, equivalent to 100–180 days postpollination, were analyzed for lipids, alkaloids, proteins, and anthocyanins. Total lipid, fatty acid, triglyceride, alkaloid, and anthocyanin accumulation increased linearly after an initial lag with embryo dry weight. Palmitic, stearic, arachidic, and oleic acids had constant rates of accumulation per micromole of total fatty acid (0.29, 0.27, 0.38, and 0.01, respectively); however, linoleic and linolenic acid accumulation decreased from 0.2 and 0.02 below 0.2 g dry weight to 0.035 and 0.0035 above 0.2 g dry weight, respectively. Monounsaturated triglycerides [palmito-oleo-stearin (POS), oleo-distearin (SOS), and oleo-dipalmitin (POP)] continued to accumulate as dry weight increased but polyunsaturated triglycerides [palmito-diolein (POO), stearo-diolein (SOO), linoleo-dipalmitin (PLP), and palmito-linoleo-olein (PLO)] ceased to accumulate at about 0.4 g dry weight. Theobromine accumulation increased linearly with dry weight after an initial lag but the rate differed with cultivar. Caffeine accumulation was low until the final stages of development. The protein pattern became dominated by 4 protein species with apparent molecular weights of 43, 34, 22, and 14 kDa as embryos matured.     

高压输电线绝缘子的革新——用合成材料代替瓷

高压输电线路的故障会引起大面积停电，并造成严重的经济损失，因此，电力公司的工程师必须关注运行的可靠性，重视输电系统的合理设计。可靠输电的一个关键因素是选择高压悬挂式绝缘子。实际上，输电系统大多数意外停电都是由绝缘子事故引起的。