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The reaction between C3H8 and N2O over steam-activated FeMFI zeolites leads to high yields towards propene (24%) and propionaldehyde (6%) at 773-798 K.
A short time (3-10 min) of microwave irradiation on the CuO/ZnO/Al2O3 oxide precursor can result in a unique tailored microstructural modification on the catalyst, leading to a significantly enhanced performance for H2 production from steam reforming of methanol.
The steam distillate prepared from fresh plants of Houttuynia cordata Thunb. (Saururaceae) was found to have direct inhibitory activity against herpes simplex virus type 1 (HSV-1), influenza virus, and human immunodeficiency virus type 1 (HIV-1) without showing cytotoxicity, but not against poliovirus and coxsackie-virus. The loss of viral infectivity was related to the duration of drug treatment. Three major components of the distillate, methyl n-nonyl ketone, lauryl aldehyde, and capryl aldehyde, also inactivated HSV-1, influenza virus, and HIV-1. These in vitro findings demonstrate that the essential oils provide virucidal activity against enveloped viruses by interfering with the function of virus envelope.
PURPOSE: Despite a rapid spread of the technique, very little is known about the laser-tissue interaction in endovenous laser treatment (EVLT). We evaluated EVLT of the incompetent greater saphenous vein (GSV) for efficacy, treatment-related adverse effects, and putative mechanisms of action. METHODS: Twenty-six patients with 31 limbs of clinical stages C(2-6), E(P), A(S,P), P(R) with incompetent GSV proven by means of duplex scanning were selected for EVLT in an outpatient setting. A 600-microm fiber was entered into the GSV via an 18-gauge needle below the knee and proceeded to the saphenofemoral junction (SFJ). After infiltration of tumescent local anesthesia, multiple laser pulses of 15 J energy and a wavelength of 940 nm were administered along the vein in a standardized fashion. D-dimers were determined in peripheral blood samples 30 minutes after completion of EVLT in 16 patients and on postoperative day 1 in 20 patients. One GSV that was surgically removed after EVLT was examined by means of histopathology. Additionally, an experimental in vitro set-up was constructed as a means of investigating the mechanism of laser action within a blood-filled tube. RESULTS: A median of 80 laser pulses (range, 22-116 laser pulses) were applied along the treated veins. On days 1, 7, and 28, all limbs except one (97%) showed a thrombotically occluded GSV. In one patient, the vessel showed incomplete occlusion. The distance of the proximal end of the thrombus to the SFJ was a median 1.1 cm (range, 0.2-5.9 cm) in the remaining patients. Adverse effects in all 26 patients were ecchymoses and palpable induration along the thrombotically occluded GSV that lasted for 2 to 3 weeks. In two limbs (6%), thrombophlebitis of a varicose tributary required oral treatment with diclofenac. D-dimers in peripheral blood were tested with normal results in 14 of 16 patients 30 minutes after completion of the procedure and elevated results in 7 of 20 patients at day 1 after EVLT. However, an increase of D-dimers from day 0 to day 1 was observed in 15 of the 16 patients undergoing tests 30 minutes after EVLT and on day 1. The 940-nm laser was demonstrated by means of in vitro experiments and the histopathological examination of one explanted GSV to act by means of indirect heat damage of the inner vein wall. CONCLUSION: EVLT of the GSV with a 940-nm diode laser is effective in inducing thrombotic vessel occlusion and is associated with only minor adverse effects. Laser-induced indirect local heat injury of the inner vein wall by steam bubbles originating from boiling blood is proposed as the pathophysiological mechanism of action of EVLT.
Two outbreaks of a febrile syndrome marked by chills, headaches, myalgia, nausea, and malaise occurred in workers who had cleaned the steam condensers of electric power turbines. Mean incubation period was 38 hours. Twenty-two of twenty-three exposed men became ill. Clinical and environmental investigation failed to reveal the etiology of the outbreaks. The circumstances and clinical syndrome have points of similarity to fever following inhalation of metal fumes and low-grade, stained cotton dust, and to Pontiac fever.
A 1949 outbreak of flu-like illness in steam-turbine condenser cleaners was investigated in 1979. Clinical and epidemiologic features matched those in previously described outbreaks of nonpneumonic legionellosis (Pontiac fever). Titers by indirect immunofluorescence using polyvalent Legionella pneumophila antigen were significantly higher for late convalescent-phase serum samples from condenser workers than for control serum samples submitted to the Centers for Disease Control. Three workers who had cleaned the condensers on several occasions had experienced recurrent illness associated with these operations, which might support the theory that nonpneumonic legionellosis is caused by an immune reaction to an inhaled antigen or bacterial toxin of L. pneumophila, rather than a true infection.
Analysis of the stomach contents of 97 white perch, Morone americana, taken from the effluent canal of a steam electric station (S.E.S.) and 106 white perch from adjacent Patuxent River waters indicated similar food habits from September 1970 through August 1971. However, 35% of all white perch taken from the heated effluent canal contained small pieces of coal and cinders, whereas only 3% of the river specimens contained such items in their stomachs. Fly ash and coal dust are present on the bottom of the S.E.S. canal, whereas little such material, if any, can be found on the river bottom in the study area. This suggests the canal fish were actively feeding in the heated effluent and not simply moving into the canal after feeding in the river. No significant difference (Pgreater than0.05) was found between the average wet weight stomach contents of the river and canal fish within the same mouth.
To resolve mixed organic and radioactive waste disposal problems, Lawrence Berkeley National Laboratory (LBNL) initiated a treatability study using the catalytic chemical oxidation (CCO) system to oxidize a mixed-waste stream and to confine tritium as part of LBNL's pollution prevention program. LBNL has also adopted a legal approach by seeking an equivalent waste-treatment determination for the CCO process, and by petitioning the United States Environmental Protection Agency (EPA) to delist F-coded treatment residues. The results of this study demonstrate that (1) the CCO process can treat aqueous wastes containing a broad range of organic chemicals and achieve more than 99.999% destruction efficiency; (2) greater than 99.9% trapping efficiency for tritiated water can be achieved using an emission-reduction system that also confines the vapor of hydrochloric acid or nitric acid to the liquid residue; and (3) neutralized treatment residues can be disposed of as low-level radioactive waste at a permitted facility after EPA has approved LBNL's petitions, or the tritium in the residues can be recycled. The high oxidation efficiency of the CCO process is mainly due to the optimized operating conditions of the CCO process and the combined effect of steam reforming in the oxidation cell and the catalytic oxidation of organic mixtures and CO in the Pt/Al2O3 catalyst bed.
Ten of twelve men who participated in the cleaning of an electric power steam turbine condenser clogged with freshwater sponge experienced an acute febrile illness. Two similar outbreaks have been previously described, one of which has been attributed to the Legionnaires' Disease bacterium. Epidemiologic studies of this case showed a syndrome very similar to the two previously reported episodes. However, the exact etiology for this outbreak has not been identified. Environmental sampling was not initiated until after the cleaning was completed. Subsequent testing did not reveal any likely cause for the outbreak. The delayed onset of symptoms and the nature of the illness pointed to an infectious agent. In the absence of any suitable criteria for employee exposure evaluation, it is suggested that crews cleaning condensers under unusually dirty conditions, especially if eye or respiratory symptoms are reported, should be provided with respiratory protection.
OBJECTIVE: To compare the efficacies of ethylene oxide gas (EOG), hydrogen peroxide gas plasma (PLASMA), and low-temperature steam formaldehyde (LTSF) sterilization methods. METHODS: The efficacies of EOG, PLASMA, and LTSF sterilization were tested using metal and plastic plates, common medical instruments, and three process challenge devices with narrow lumens. All items were contaminated with Bacillus stearothermophilus spores or used a standard biological indicator. RESULTS: EOG and LTSF demonstrated effective killing of B. stearothermophilus spores, with or without serum, on plates, on instruments, and in process challenge devices. PLASMA failed to adequately sterilize materials on multiple trials in several experiments, including two of three plates, two of three instruments, and all process challenge devices. CONCLUSIONS: Our results suggest that PLASMA sterilization may be unsuccessful under certain conditions, particularly when used for items with complex shapes and narrow lumens. Alternatively, LTSF sterilization demonstrates excellent efficacy and is comparable to EOG sterilization. LTSF could potentially act as a substitute if EOG becomes unavailable due to environmental concerns.
Three experiments were conducted to determine the effects of pelleting and extrusion of feeds on the utilization of phytate P by broilers. The first experiment investigated the effects of pelleting the whole corn-soybean meal (SBM) diet, the corn, or SBM separately on phytate P utilization. The P-deficient basal diet contained 0.5% total P and 0.2% phytate P. Steam pelleting the whole diet, the corn, or SBM separately did not decrease the severity of the P deficiency obtained and there were no indications of increased phytate P utilization. In the second experiment, the whole corn-SBM P-deficient diet was extruded. Extrusion of the diet did not influence bone ash and P rickets, both sensitive criteria of P deficiency. Extrusion decreased Ca, P, and phytate P retention and decreased the ME value of the diet. In the third experiment, phytate P retention by chickens fed three commercial pelleted diets was compared to chicks fed the corn-SBM P-deficient diet. Phytate P retention by the chickens fed the commercial diets was much lower than retention by chickens fed the corn-SBM P-deficient diet. These studies gave no indication that pelleting or extrusion of corn-SBM diets would increase phytate P utilization by broiler chickens.
Native soybean lectins (SBL) could potentially have deleterious effects on young animals. The objectives of this study were to determine the optimum processing temperature and time at which SBL is inactivated and to investigate the possibility of using urease activity (UA) to predict residual lectin levels in soybean meal (SBM). Raw defatted SBM was steam-heated at incremental temperatures between 90 and 120 degrees C for 5 to 20 min in an autoclave. The processed meals were subjected to native-PAGE and measurement of total carbohydrate-binding lectin (TCBL), agglutinating lectin (AL), UA, and trypsin inhibitor (TI). Processing severity was evaluated by determining protein solubility in 0.2% potassium hydroxide. Results indicated that levels of all antinutrients (TCBL, AL, UA, and TI) decreased with increasing processing temperature (P < 0.05). The intensity of the lectin band on the electrophoresis gel was considerably reduced when meal was heated at 100 degrees C for 5 min. This result implied that lectin inactivation occurred at 100 degrees C. More than 90% of all the original antinutrient levels in the raw meal were destroyed when meals were heated at 100 degrees C for 5 min. Meals processed at 100 degrees C for 5 to 20 min had protein solubility values (80 to 85%) indicative of adequate processing. The denaturation pattern of UA was highly correlated with that of SBL (r > or = 0.73), indicating that UA could be used for monitoring lectin levels in commercial meals. We concluded that UA of 0.03 to 0.09 units of pH change are indicative of adequately processed meals that contain negligible lectin levels.
During the years 1986 to 1990, an increasing number of cases of acute carbon monoxide (CO) poisoning were encountered in the Emergency Department Hacettepe University Hospital in Ankara, Turkey. Between January 1 and March 31, 1991, all the patients presenting with complaints compatible with CO poisoning were evaluated; the diagnosis was confirmed in 55 of the 5795 people who attended the Emergency Department during this period. In all cases the source of CO intoxication was determined. Among these patients, nausea or vomiting and headaches were the most common complaints (occurring in 100% and 85%, respectively). At least transient impairment of alertness was observed in 29% of cases. The carboxyhaemoglobin levels ranged from 3.80 to 48.1% (median 14.2%). Two comatose patients who developed a non-cardiogenic pulmonary oedema required mechanical ventilation. One of them was discharged from the hospital with mild cerebral disability. Another patient developed an acute myocardial infarction. In all the cases in this series, the source of CO poisoning was identified as improper combustion of recently marketed steam coal in inadequately ventilated bucket stoves.
Detailed studies of elementary chemical processes on well-characterized single crystal surfaces have contributed substantially to the understanding of heterogeneous catalysis. Insight into the structure of surface alloys combined with an understanding of the relation between the surface composition and reactivity is shown to lead directly to new ideas for catalyst design. The feasibility of such an approach is illustrated by the synthesis, characterization, and tests of a high-surface area gold-nickel catalyst for steam reforming.
Pontiac fever affected ten men who had cleaned a steam turbine condenser with compressed air. Previous epidemics of Pontiac fever and Legionnaires' disease--both caused by Legionella Pneumophila (proposed sp. nov.)--involved "airborne spread" from air-conditioning cooling towers or evaporative condensers. Aerosols of contaminated water in heat-rejection systems appear to be important sources of epidemic legionellosis.
Twenty-one commercially available chemical steam sterilization indicators were processed in an empty autoclave for various times at temperatures between 240 and 270 degrees F (ca. 116 and 132 degrees C). The time required to reach a sterilized reading at each temperature was plotted on a semilogarithmic time-temperature plot and compared with the time-temperature sterilization curve for Bacillus stearothermophilus. Five of the indicators had time-temperature kinetics similar to those of B. stearothermophilus, but three of these overestimated the effect of processing. Two of the indicators overestimated the effect of processing and were less sensitive to temperature changes when was B. stearothermophilus. Thirteen of the indicators had time-temperature curves that crossed the B. stearothermophilus plot. One indicator produced such ambiguous results that no determinations could be made with it. Out of 21 indicators tested, only 2 appear to be capable of accurately integrating the time-temperature effect at temperatures between 240 and 270 degrees F. The other indicators should be used only after careful analysis of their suitability for use at a given temperature.
Data obtained by independent tests on each of 483 batches of Rhizobium inoculants for Glycine max, Medicago sativa, and Arachis hypogaea, manufactured commercially in South Africa, are reported and discussed. Whereas the average cell count per gram per batch was well in excess of 10, inoculants for G. max and M. sativa manufactured with peat treated with gamma irradiation at a dose of 50 kGr contained significantly higher numbers of Rhizobium cells than inoculants from peat which received 25 kGr. Inoculants for M. sativa manufactured with steam-sterilized peat were similar in quality to those prepared with peat irradiated at a dose of 50 kGr. Contrary to the inoculants for G. max and M. sativa, the Rhizobium strain used in inoculants for A. hypogaea was apparently insensitive to the effect on peat of the higher gamma irradiation dosage.
A steam sterilizer (autoclave) was tested to determine the operating parameters that affected sterilization of microbiological waste. Tests involved standardized loads (5, 10 ad 15 lb [ca. 2.27, 4.54, and 6.80 kg, respectively]) contaminated petri plates in autoclave bags placed in polypropylene or stainless steel containers. Thermal and biological data were obtained by using a digital potentiometer and a biological indicator containing spores of Bacillus stearothermophilus, respectively. The transfer of heat was more efficient when smaller loads of microbiological waste were tested and stainless steel rather than polypropylene containers were used. A single bag with the sides rolled down to expose the top layer of petri plates allowed heat to pass better than did a single bag with the top constricted by a twist-tie. The presence of water in the autoclave bag did not significantly improve heat-up time in stainless steel or polypropylene containers. The results of biological tests substantiated the temperature data. When 10 or 15 lb of microbiological waste was exposed to various test conditions, the only condition that ensured the destruction of B. stearothermophilus involved the use of a stainless steel container (with or without water) for 90 min. Autoclaving for 45 min resulted in the destruction of bacteria included in 10 lb (136 +/- 3 plates) or 15 lb (205 +/- 6 plates) of microbiological waste when stainless steel containers with or without water or polypropylene containers with water used, whereas 60 min was required to kill all bacteria if polypropylene containers without water were used.