The effect of exothermic reactions during regeneration on the NOX trapping efficiency of a NOX storage/reduction catalyst

An unusual behavior was observed during experiments conducted at 371 and 465 °C with a commercial NO_X storage/reduction catalyst: the outlet NO_X concentration during the trapping phase reached a cycle minimum after regeneration, increased for 20–30 s, as expected, but then surprisingly decreased, indicating the catalyst had become more efficient in trapping the entering NO_X. The results reported in this letter indicate that this phenomenon was caused by a superposition of two factors: a substantial exotherm associated with the regeneration event from reductant reacting with surface oxygen species and a negative impact of an evolving temperature profile on the dynamic NO_X storage capacity.     

Investigation of the Effect of Accelerated Hydrothermal Aging on the Cu Sites in a Cu-BEA Catalyst for NH3-SCR Applications

The influence of hydrothermal aging between 500 and 900 °C for 3 h, on the structure of a Cu-Beta catalyst was studied in this work. The XRD measurements indicated a structural breakdown of the zeolite upon 900 °C hydrothermal aging. This was confirmed from the loss of surface area as measured by BET method. The temperature for the zeolite structure break down was different between the powder bed as opposed to the sample that was washcoated on a cordierite monolith, which was most likely due to slightly different aging conditions and the presence of binders. The strong increase in the intensity of the Cu2p XPS peak indicated that the surface is enriched of copper at higher temperatures due to the zeolite structure collapse. The presence of CuO is usually accompanied by a satellite peak, which was clearly observed at higher binding energies for the catalysts aged at 800 and 900 °C. The XPS results are in good agreement with the UV–Vis experiments, which also point to the formation of copper oxide after high temperature aging.     

STANDARD METHOD FOR DETERMINING LEACHABILITY OF LEAD FROM LEAD FRITS*

A procedure is developed for determining leachable lead in lead frits. The procedure is sufficiently simple for use by control laboratories whereby duplicate results can be obtained. It is based on leaching the lead at 40°± 0.5°C. from frit (-180, +200-mesh particles) with 0.137 N HCl and precipitating the lead as PbCrO₄.     

V beta-specific immunotoxin selectively kills acetylcholine receptor-reactive T lymphocytes from mice with experimental autoimmune myasthenia gravis

Immunization of C57BL/6 mice with purified acetylcholine receptor (AChR) is known to induce a T cell-dependent antibody response that results in experimental autoimmune myasthenia gravis (EAMG). Since past observations link V beta 6+ T cells with a prominent AChR epitope specificity, a V beta 6-specific immunotoxin (VIT6) was tested in vitro for its ability to selectively kill monoclonal and polyclonal T cells that demonstrate reactivity against AChR. Results described below clearly demonstrate the ability to selectively kill AChR-reactive T cells based on their expression of a particular V beta-associated antigen receptor.     

A phase II/III trial of antimicrobial therapy with or without amikacin in the treatment of disseminated Mycobacterium avium infection in HIV-infected individuals. AIDS Clinical Trials Group Protocol 135 Study Team

OBJECTIVE: To determine the clinical and microbiologic benefit of adding amikacin to a four-drug oral regimen for treatment of disseminated Mycobacterium avium infection in HIV-infected patients. DESIGN: A randomized, open-labeled, comparative trial. SETTING: Outpatient clinics. PATIENTS: Seventy-four patients with HIV and symptomatic bacteremic M. avium infection. INTERVENTIONS: Rifampin 10 mg/kg daily, ciprofloxacin 500 mg twice daily, clofazimine 100 mg every day, and ethambutol 15 mg/kg orally daily for 24 weeks, with or without amikacin 10 mg/kg intravenously or intramuscularly 5 days weekly for the first 4 weeks. MAIN OUTCOME MEASURE: Clinical and microbiologic response at 4 weeks; quantitative level of bacteremia with M. avium. RESULTS: No difference in clinical response was noted with the addition of amikacin to the four-drug oral regimen, and only 25% in either group had a complete or partial response at 4 weeks. A comparable quantitative decrease in bacteremia was noted in both treatment groups, with 16% of patients being culture-negative at 4 weeks and 38% at 12 weeks. Toxicities were mainly gastrointestinal. Amikacin was well tolerated. Median survival was 30 weeks in both groups. CONCLUSIONS: The addition of amikacin to a four-drug oral regimen of rifampin, ciprofloxacin, clofazimine, and ethambutol did not provide clinical or microbiologic benefit.     

Victor Tango车队“Odin”战车杀手锏：应用NI LabVIEW助威DARPA无人驾驶汽车城市挑战赛

"Odin是仅有的一辆全面应用LabVIEW的赛车,并且取得了第三名的成绩,仅比领先者慢了几分钟。"DARPA城市挑战赛要求路上车辆在城市环境中无人驾驶行驶。在整个赛程中,全自主的无人车要在不到6小时中行驶60英里,并在道路、十字路口、停车场等交通环境里行驶。比赛开始时,一份任务文档规定了比赛道路     

INFLUENCE OF SODIUM SILICATE COMPOSITION ON ITS BEHAVIOR WITH SODIUM CARBONATE AS A CASTING SLIP DEFLOCCULANT*

A study of six brands of silicate of soda used in a typical ceramic casting slip discloses the effect of the Na₂O to SiO₂ ratio on hydrometer readings, pH, viscosity, casting rate, water retention, drying shrinkage, dry strength, firing shrinkage, fired strength, and fired absorption. The effect of varying the amount of electrolyte both above and below that required for complete deflocculation is also reported.     

Spinocerebellar ataxia and HLA linkage: risk prediction by HLA typing

To determine the possibility of genetic linkage of spinocerebellar ataxia with the histocompatibility loci, we performed HLA typing and linkage analysis on 19 members of a kindred in which spinocerebellar ataxia was segregating in an autosomal dominant inheritance pattern. The ataxia locus was located on chromosome 6 at 12-cM distance from the HLA complex with lod score of 3.15 (odds is greater than 1400:1 favoring linkage over chance findings). Thus, the presence of the ataxia gene in members of this kindred at risk can be predicted with about 90 per cent accuracy by means of HLA typing in informative matings.     

Gentamicin penetration into normal rabbit nucleus pulposus

STUDY DESIGN: Radioactively labeled gentamicin was administered to 24 rabbits to assess the concentration of antibiotic in the nucleus pulposus. OBJECTIVES: The purpose of the study was to investigate the pharmacokinetics of gentamicin penetration into normal rabbit nucleus pulposus. SUMMARY OF BACKGROUND DATA: Disc space infection is a complication of spinal surgery that can be prevented by prophylactic antibiotics. Gentamicin can be used in conjunction with other antibiotics as a prophylactic agent. One previous study demonstrated that a similar antibiotic, tobramycin, penetrates the disc, but no data have been reported on the pharmacokinetics of disc penetration. METHODS: Twenty-four rabbits were given an intravenous injection of gentamicin labeled with iodine 125. Four rabbits were killed at hourly intervals 1 to 6 hours after injection. Specimens of nucleus pulposus, blood, whole liver, and saline-perfused liver were obtained and prepared. The radioactivity in the specimens was measured. RESULTS: The gentamicin concentration in the nucleus pulposus peaked at 2 hours and remained at this level for the duration of the experiment. Twenty percent of the gentamicin recovered from the nucleus pulposus was tissue bound. CONCLUSIONS: Gentamicin concentration in the rabbit nucleus pulposus does not peak until 2 hours after an intravenous bolus of drug. If gentamicin penetrates human nucleus pulposus in a similar fashion, this study could have implications for the timing of administration of this agent for prophylaxis.     

A NON-MARKOVIAN MODEL FOR PARTICLE MOTION IN FLUIDIZED BEDS

The notion of modeling particle motion in fluidized beds by stochastic methods is extended to include non-Markovian behavior. The inclusion of such “memory” terms should more adequately represent the key physical considerations. A general memory equation is first introduced. Two expressions for the so-called memory function are then suggested and subsequently used to generate autocorrelation functions which favorably represent the available experimental data.