Effect of forming gas anneals on the photoluminescence from nanocrystalline silicon formed by Si implantation into SiO2 matrix

The blue region of the room temperature photoluminescence spectrum from Si nanocrystallites formed in SiO₂ by Si⁺ ion implantation has been observed for the first time after annealing in a forming gas (10% H₂ + 90% N₂) ambient. Thermally grown SiO₂ on Si substrates were implanted with a dose of 2 × 10¹⁷ Si⁺ cm⁻² at energies of 200 keV and 400 keV. For reference purposes, quartz silica was implanted also with the same dose of 200 keV Si⁺ ions. The implanted samples were annealed in nitrogen and forming gas at 900°C for 3 to 180 min. Both the SiO₂ and quartz samples exhibited luminescence at about 380 nm which was weak, but detectable, before annealing. During extended anneals in forming gas, the intensity increased by a factor of about 2 above that recorded after a nitrogen anneal but the peak position was unchanged. The intensity was greater in samples annealed in forming gas which is due to the additional hydrogen. It would seem that this blue luminescence originates from new luminescent centres in the matrix caused by the Si⁺ ion implantation.     

Participants' perceptions of a phase I colon cancer chemoprevention trial

To assess participants' perceptions of a phase I colon cancer chemoprevention trial using a calcium intervention, questionnaires were mailed to trial participants at the conclusion of the study. Responses to questionnaire items reported here include (1) perceived benefits and barriers of participation, (2) interest in participating in future trials, (3) willingness to pay trial expenses out of pocket, and (4) posttrial continuation of the calcium regimen. The study found that the most highly rated trial benefit was the perception of potential colon cancer prevention; the trial barrier reported to be the most troublesome was inappropriate or mistaken billing for study visits. Three fourths of the subjects expressed an interest in future trials of the same duration. For trials of longer duration, this percentage decreased to 66%. Approximately half did not object to participation in future trials involving placebos, and just over one third indicated that they would either definitely (8%) or probably (27%) have joined the calcium trial even if they had to pay some study expenses out of pocket. Over 90% indicated they would continue taking the calcium pills if calcium is shown to be effective. The level of perceived benefits was positively associated with reported interest in participating in future trials of the same and longer durations, and the level of reported difficulty with trial pills and procedures was inversely related to interest in future placebo-controlled trials. The results of this study, in conjunction with results of prospective studies of trial participation, may be applied in future chemoprevention trials to facilitate recruitment, reduce attrition, and promote positive trial experiences for participants by emphasizing frequently reported benefits and minimizing frequently reported barriers.     

Salt reduction in municipal sewage allocated for reuse: the outcome of a new policy in Israel.

Israel is presently reusing about 70% of its sewage and the buildup of salts in soils has been detected in some areas of the country. Prevention of sewage salt enrichment is one of the most immediately available solutions. The discharge of brines to municipal sewers is now prohibited and they are discharged to the sea. Discharge of brines to the sea has increased from 580,000 m3 in 1999 to more than 700,000 m3 in 2002. These salts are thus definitively taken out of the reuse cycle, year after year. The concentration of salts in industrial effluents is presently limited by the national water law and a unique regulation limiting the Boron and Sodium content in detergents has been implemented. Israeli industry has undergone a radical change in recent years. Many factories and all the hospitals have adopted K or Ca for softening and neutralization, while others have shifted to reverse osmosis. The concentration of Cl and Na in the sewage reaching treatment plants is declining. The addition of Cl to sewage has dropped from 120 mg/l to 70 mg/l. The average Boron concentration in sewage has dropped from 0.6 mg/l to 0.3 mg/l and should reach 0.2 mg/l by 2008.     

Sleep-disordered breathing and neuropsychological deficits. A population-based study

The relationship of sleep-disordered breathing (SOB) to neuropsychological deficits was investigated with cross-sectional data from the Wisconsin Sleep Cohort Study, a population-based study of the natural history of SDB. A sample of 841 employed men and women ages 30 to 60 yr was studied by overnight polysomnography to assess the frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index, AHI). Prior to overnight polysomnography, the participants were given a battery of neuropsychological tests for functionally important capacities including motor skills, attention, concentration, information processing, and memory. Principal factor analysis of all the neuro-psychological test data revealed a psychomotor efficiency and a memory factor. Multiple regression analysis showed a significant negative association between logarithmically transformed AHI (LogAHI) and psychomotor efficiency score independent of age, gender, and educational status (p = 0.017). The relationship was not explained by self-reported sleepiness. No significant relationship was seen between LogAHI and memory score. In assessing the clinical significance of mild SDB, we estimate that an AHI of 15 is equivalent to the decrement in psychomotor efficiency associated with 5 additional yr of age, or to 50% of the decrement associated with hypnosedative use.     

Design rules for the wallcooled hydrothermal burner (WHB)

The results of a process analysis and an experimental exploratory study of supercritical water oxidation (SCWO) show that elements of combustion technology are suitable to overcome the technical problems of SCWO. The Film Cooled Hydrothermal Burner (FCHB) which operates at 25 MPa up to 2000 K in the reaction zone keeping wall temperature under stress at 300 to 400 K shows further development potential of the Wallcooled Hydrothermal Burner (WHB) concept for SCWO, a still promising waste treatment process.     

Role of laparoscopy in the management of chronic pelvic pain

OBJECTIVE: The pharmacokinetics of N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, was investigated in patients with septic shock. METHODS: Blood was sampled at intervals before, during and after 12-h infusion of L-NAME 1 mg x kg(-1) x h(-1) in nine septic shock patients for determination of plasma concentrations by high-performance liquid chromatography (HPLC). In three patients the renal clearance of the drug was determined. RESULTS: Incubation of L-NAME with plasma and blood in vitro revealed hydrolysis to N(G)-nitro-L-arginine (L-NOARG), the active inhibitor of NO synthesis. L-NOARG did not undergo further degradation. Continuous intravenous infusion of 1 mg x kg(-1) x h(-1) of L-NAME for 12 h in patients with septic shock increased blood pressure and resulted in increasing plasma concentrations of L-NOARG (Cmax 6.2 microg x ml(-1) at 12 h) whereas L-NAME concentrations reached a plateau within 1.5 h (Cmax 1.0 microg x ml(-1)). After the infusion was stopped L-NAME disappeared from the plasma rapidly (half-life 19.2 min) whereas L-NOARG concentration declined slowly (half-life 22.9 h). The calculated volume of distribution for L-NAME was 0.451 x kg(-1) body weight and 1.961 x kg(-1) for L-NOARG. The renal clearance for L-NOARG was 3.5% of total body clearance for L-NOARG, whereas L-NAME could not be detected in urine. CONCLUSION: We conclude that vasoconstriction with L-NAME in septic patients may result from hydrolysis to L-NOARG, the active inhibitor of NO synthesis. The long plasma half-life and large volume of distribution for L-NOARG suggests extensive distribution to extravascular tissues. Since renal excretion is minimal, elimination of the metabolite L-NOARG follows other pathways.     

Detection of soluble methane monooxygenase producing Methylosinus trichosporium OB3b by polymerase chain reaction

The soluble methane monooxygenase (sMMO) enzyme complex of methanotrophs cometabolizes haloaliphatic compounds such as trichloroethylene. Two 18-mer oligonucleotides as primary primers and a nested primer of the same length were selected to amplify specific DNA sequences of the sMMO gene cluster using polymerase chain reaction (PCR). Two DNA fragments of sizes 270 and 400 base pairs were obtained when purified DNA from the methanotroph Methylosinus trichosporium OB3b was used as template. The primers were specific for sMMO sequences of M. trichosporium, since none of the 13 bacterial isolates screened yielded the expected length of PCR-amplified DNA fragments. The detection limit of the PCR method was 5 x 10(2) cells of M. trichosporium. The sMMO sequences were successfully amplified in groundwater (containing native microbial population) when seeded with M. trichosporium, FP1 sense (5'-ATGTCCAGCGCTCATAAC-3'), RP1 antisense (5'-TCAGATGTCGGTCAGGGC-3'), FP2 sense nested (5'GCCATCATCGGTCAGGGC-3'), and FP2 sense nested (5'-GCCATCATCGAGGACATC-3').