Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “STEAM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1982

Steam distillation and gas-liquid chromatographic determination of triallate and diallate in milk and plant tissue.

A procedure based on steam distillation is described for the determination of residues of the thiocarbamate herbicides diallate and triallate. The herbicides are steam-distilled directly from aqueous suspensions of milk and plant samples and trapped in hexane. After column cleanup on either activated Florisil or silica cartridges, samples are quantitated by gas-liquid chromatography. Recoveries of diallate and triallate from milk, lettuce, peas, corn, canarygrass seed and straw, and flax straw ranged from 77 to 96%.

Animals↗
PubMed1984

The effect of steam sterilization on plaster casting material.

Plaster-impregnated gauze was autoclaved as a preventative measure against infection. The mechanical properties and the hardening time of casts made with autoclaved plaster were investigated by measuring flexural yield stress and flexural modulus of elasticity. A cantilever bending test was used to determine the time required to harden. The average yield stress in bending was reduced by an average of 8% and the modulus of elasticity was unchanged by the steam sterilization. The time required for the plaster splint to harden was increased by a factor of 5.6 after steam sterilization. Although the reduction in the yield strength was not prohibitive, the increase in hardening time was unacceptable. The use of gas sterilization is recommended when a sterile cast is necessary because gas sterilization does not increase hardening time.

Casts, Surgical↗
PubMed1981

Steam vaporizer injuries.

There were an estimated 656 cases of vaporizer-related injuries seen in hospital emergency departments in 1979. Two cases of burns with respiratory involvement are described. Both children were directly exposed to steam from commercial vaporizers and suffered cutaneous and respiratory burns. These cases emphasize the hazards of steam vaporizers, devices that have no proven therapeutic benefits.

Aminophylline↗
PubMed1994

[Study of bronchoalveolar lavage fluid harvested from the dogs with steam inhalation injury].

The significances of analyzing bronchoalveolar lavage fluid (BALF) were studied using a steam inhalation injury model. Bronchoalveolar lavage was carried out at 1 and 5 h after steam inhalation injury. The parameters investigated included cellular analysis, the total protein content, malondialdehyde (MDA) content, the activity of superoxide dismutase (SOD), and the angiotensin converting enzyme (ACE) in the BALF, and pathologic examination of lungs. The study indicated that some informations of the pathophysiological changes in the lungs after inhalation injury could be acquired by the BALF analysis.

Animals↗
PubMed1994

New-onset asthma after exposure to the steam system additive 2-diethylaminoethanol. A descriptive study.

Through a leak in the steam heating system, the anticorrosive agent 2-diethylaminoethanol was released into the air of a large office building. Irritative symptoms were experienced by most of the 2500 employees, and 14 workers developed asthma within 3 months of exposure. This study was undertaken to review clinical characteristics of these asthmatics. Environmental exposure monitoring data and medical records were reviewed. Seven of 14 cases were defined as "confirmed" and 7 of 14 as "suspect," using the National Institute for Occupational Safety and Health surveillance case definition of occupational asthma. Spirometry was positive in 4 of 14 of the cases and peak flow testing in 10 of 14. Three cases were diagnosed on the basis of work-related symptoms and physical examination alone. The study suggests that acute exposure to the irritating steam additive 2-diethylaminoethanol was a contributing factor in the development of clinical asthma in this population.

Adult↗
PubMedDate not supplied

Effect of steam inhalation on mucociliary activity in patients of chronic pulmonary disease.

Increased mucociliary activity has been observed with several modalities, including inhalation which seems to achieve faster drug delivery. In patients of chronic lung disease, the mucociliary activity is known to be impaired. The effect of steam inhalation on mucociliary transport time was studied in these patients. It was found that steam inhalation improved mucociliary activity significantly (p < 0.001) in both groups receiving either only bronchodilators, or bronchodilators as well as steroids.

Adolescent↗
PubMed1998

Comparison of cerebral occipital gray and parietal white matter metabolite differences using PRESS and STEAM at different echo times.

BACKGROUND: Reports regarding the differences in metabolite ratios with different echo times (TEs) at various brain regions are rare. The purpose of this study is to investigate in Chinese the cerebral metabolite ratios in gray matter (GM) and white matter (WM) using both STEAM and PRESS techniques at TEs of 30 ms and 136 ms, respectively. MATERIALS AND METHODS: Using GE Signa 1.5 T Scanner with STEAM and PRESS sequences, automated single voxel localized proton magnetic resonance spectroscopy (1H-MRS) were applied to identify the metabolite ratio differences in cerebral parietal white and occipital gray matter of healthy volunteers. RESULTS: Metabolite ratios between GM and WM were significantly different in N-acetyl aspartate/creatine (Cr), choline/Cr and myo-inositol/Cr. There were also significant differences in metabolite ratios when different echo times were applied. CONCLUSION: Reliable metabolite ratios at different brain regions can be obtained using automated data acquisition and spectral processing in single voxel localized 1H-MRS. This technique may remove user-dependent bias and provide more efficient and consistent ways to analyze the spectral data. However, one must be careful in interpreting spectroscopic data based on different regions and acquisition parameters.

Adult↗
PubMed1998

[Content of volatile in steam phenols in the main stream of cigarette smoke from selected brands of cigarettes].

Phenols constitute an important toxic component of the main stream (MS) of cigarette smoke. The content of volatile fraction of that group of compounds in MS depends on the tobacco type and conditions in which cigarettes are smoked, as well as on the filters applied. The purpose of the research was to determine the content of volatile in steam phenols in the MS of selected brands of cigarettes produces in Poland, as well as imported ones, and the assessment of the toxicity of doses of the phenols that smokers were exposed to. Cigarettes conditioned in constant humidity were smoked in standard conditions in the simulator of smoking, designed by the authors, while MS was absorbed in Zaitcev washers, filled with methanol. The absorbed phenols were distilled in steam and extracted with ethyl acetate. Then the phenols were separated by the method of overpressure thin-layer chromatography on DC Alufolien Polyamid 11F254 Merck chromatoplates, in the developing system chloroform-methanol 99:1 v/v, were induced with sodium diazofluoroborate, and after eultuion the separated phenol, and o-cresol were determined, as well as the non-separated mixture of p- and m-cresols, by the spectrophotometric method. The determined contents of phenols in MS were assessed regarding their toxicity applying the criteria of environmental exposure. When calculating the results, the efficiencies of the applied in the analytical procedures processes of absorption, distillation and extraction of the investigated phenols previously determined experimentally, were taken into consideration. The content of determined compounds in the brands of the cigarettes examined was in the case of phenols, changing within the range from 41.25 +/- 1.15 to 7.60 +/- 0.93 (the average of 20.31 +/- 9.61 micrograms per cigarette); in the case oo-cresol it was within the range from 28.16 +/- 0.95 to 5.72 +/- 0.53 (the average of 11.56 +/- 6.7), while for the non-separated p- and m-cresols the range was from 21.12 +/- 0.5 to 7.31 +/- 0.45 (the average amounted to 11.48 +/- 4.98 micrograms per cigarette The conclusions of the study were the brands of cigarettes significantly influences the content of the phenols examined in the cigarette smoke the phenols determined coexist in the MS of examined cigarettes in similar proportions the doses of phenols inhaled by a smoker during a day with the MS of examined brands of cigarettes participate essentially in the toxicity of the cigarette smoke and smoking 20 cigarettes a day causes the smoker's organism to be exposed to incomparably larger doses of phenols than those from unpolluted atmospheric air.

Chromatography, Thin Layer↗
PubMed2000

Effect of substrate and cellulase concentration on simultaneous saccharification and fermentation of steam-pretreated softwood for ethanol production.

Economic optimization of the production of ethanol by simultaneous saccharification and fermentation (SSF) requires knowledge about the influence of substrate and enzyme concentration on yield and productivity. Although SSF has been investigated extensively, the optimal conditions for SSF of softwoods have yet not been determined. In this study, SO2-impregnated and steam-pretreated spruce was used as substrate for the production of ethanol by SSF. Commercial enzymes were used in combination with the yeast Saccharomyces cerevisiae. The effects of the concentration of substrate (2% to 10% w/w) and of cellulases (5 to 32 FPU/g cellulose) were investigated. SSF was found to be sensitive to contamination because lactic acid was produced. The ethanol yield increased with increasing cellulase loading. The highest ethanol yield, 68% of the theoretical based on the glucose and mannose present in the original wood, was obtained at 5% substrate concentration. This yield corresponds to 82% of the theoretical based on the cellulose and soluble glucose and mannose present at the start of SSF. A higher substrate concentration caused inefficient fermentation, whereas a lower substrate concentration, 2%, resulted in increased formation of lactic acid, which lowered the yield. Compared with separate hydrolysis and fermentation, SSF gave a higher yield and doubled the productivity.

Carbohydrate Metabolism↗
PubMed1984

Crosslinked agarose encapsulated sorbents resistant to steam sterilization. Preparation and mechanical properties.

The application of agarose in hemoperfusion is hampered by the lack of a suitable sterilization method. A technique has been developed for the crosslinking of agarose encapsulated sorbents by the reaction with 1,3-dichloro-2-propanol (DCP) under strong alkaline conditions. A twofold molar excess of DCP with respect to agarose and an equimolar amount of sodium hydroxide at a concentration of 0.3 mol/L with a reaction time of 1-4 h at 50 degrees C are found to be the optimal conditions. The compressive strength of crosslinked beads is increased by a factor of 4. Agarose capsules are found to degrade by the influence of gamma radiation, but are resistant to steam sterilization at 134 degrees C during at least 30 min when crosslinked.

Adsorption↗
PubMed1988

In vivo recovery and half-life time of a steam-treated factor IX concentrate in hemophilia B patients. The influence of reagents and standards.

Factor IX (FIX) recovery and half-life was measured in ten hemophilia B patients under standardized conditions. Each patient received a steam-treated high-purity factor IX concentrate at a dose of 19-39 U/kg body weight. FIX activity was determined using a one-stage assay, which was calibrated against the international concentrate standard (reagents from Immuno, Heidelberg). The in vivo recovery ranged from 24% to 53% (mean value 37.7%) and the half-disappearance time (HDT) from 8-30 h (mean 16.7 h). In four of the ten patients, the distribution and elimination half-lives were estimated and ranged from 0.3 h to 3.9 h (mean 1.4 h) and from 28.6 h to 39.7 h (mean 33.1 h), respectively. In six patients FIX was redetermined using a different FIX deficient plasma and a plasma standard (reagents from Merz & Dade, Munich, FRG). Recoveries and HDT based on the results obtained with this method were significantly higher (68.2% vs 39.7%; p less than 0.05), and longer (14.8 h vs 10.6 h; p less than 0.05), respectively. FIX activity was also measured by both assay systems in 100 healthy subjects (50 males, 50 females). The reagents from Immuno yielded a mean value of 0.77 U/ml, while the mean FIX activity utilizing standards and reagents from Merz & Dade was 1.11 U/ml (p less than 0.000001). The coefficient of correlation between the FIX activity measurements, as determined in 100 healthy subjects and 6 hemophilia B patients using the different test systems, was r = 0.9 (N = 159; y = 0.08 +/- 1.3* chi; p less than 0.001). Our data suggest that recovery and HDT of factor IX concentrate strongly depend on the assay and calibration conditions and that an international FIX activity plasma standard is urgently required.

Adolescent↗
PubMed1990

Morphological changes of poly(ethylene terephthalate) on multiple steam sterilization.

Poly(ethylene terephthalate) (PET) was steam sterilized by autoclaving for 15, 30 and 60 min. The thermal properties, T m, delta-H and percent crystallinity were determined using differential scanning calorimetry. Molecular weight distribution was determined using gel permeation liquid chromatography. Crystallinity of PET was also monitored by infrared spectrophotometry. The analyses indicate that that chain scission and cyclization reactions take place in PET, forming cyclic oligomers, that can migrate to the polymer surface and which may affect long term performance of PET.

Calorimetry, Differential Scanning↗
PubMed1996

Burns and inhalation injury caused by steam.

Injury to the respiratory tract from inhalation of steam, although rare, often leads to acute pulmonary insufficiency. The injury to the alveolar epithelium results in increased pulmonary capillary permeability, pulmonary oedema and interfering abnormalities in gas exchange. Vigorous treatment should be instituted in these patients to obtain optimal outcome.

Acute Disease↗
PubMed2007

Steam pretreatment of H(2)SO(4)-impregnated Salix for the production of bioethanol.

In the bioconversion of lignocellulosic materials to ethanol, pretreatment of the material prior to enzymatic hydrolysis is essential to obtain high overall yields of sugar and ethanol. In this study, steam pretreatment of fast-growing Salix impregnated with sulfuric acid has been investigated by varying the temperature (180-210 degrees C), the residence time (4, 8 or 12 min), and the acid concentration (0.25% or 0.5% (w/w) H(2)SO(4)). High sugar recoveries were obtained after pretreatment, and the highest yields of glucose and xylose after the subsequent enzymatic hydrolysis step were 92% and 86% of the theoretical, respectively, based on the glucan and xylan contents of the raw material. The most favorable pretreatment conditions regarding the overall sugar yield were 200 degrees C for either 4 or 8 min using 0.5% sulfuric acid, both resulting in a total of 55.6g glucose and xylose per 100g dry raw material. Simultaneous saccharification and fermentation experiments were performed on the pretreated slurries at an initial water-insoluble content of 5%, using ordinary baker's yeast. An overall theoretical ethanol yield of 79%, based on the glucan and mannan content in the raw material, was obtained.

Acids↗
PubMed2004

Comparison of different extraction methods: steam distillation, simultaneous distillation and extraction and headspace co-distillation, used for the analysis of the volatile components in aged flue-cured tobacco leaves.

Steam distillation (SD), simultaneous distillation and extraction (SDE) and headspace co-distillation (HCD) were compared here for their effectiveness in the extraction of volatile compounds from tobacco. The different grades of aged flue-cured tobacco leaves extracted by the three methods respectively were analyzed using GC-MS. Mass spectra or authentic compounds were used to identify around 408 components in various volatile fractions. On the one hand, the qualitative comparison showed that more compounds were detected in HCD extract (391 components) than in SDE extract (377 components), and the approximately quantitative analysis showed that the total amount of volatile components in SDE extract (445.48 microg/g) was much more than that in HCD extract (315.72 microg/g). But on the other hand, HCD was the most efficient for nearly all the highly volatile compounds among the three methods. As to low-volatile compounds such as lactones, long chain aldehydes, ketones, alcohols, and esters, more was detected in SDE extract than in HCD extract. The SD method (322 components, total amount 228.42 microg/g) was the lowest sensitive to all compounds except semi-volatile fatty acids among the three methods.

Gas Chromatography-Mass Spectrometry↗
PubMed2004

Adsorption of Trichoderma reesei CBH I and EG II and their catalytic domains on steam pretreated softwood and isolated lignin.

The presence of lignin has shown to play an important role in the enzymatic degradation of softwood. The adsorption of enzymes, and their constituent functional domains on the lignocellulosic material is of key importance to fundamental knowledge of enzymatic hydrolysis. In this study, we compared the adsorption of two purified cellulases from Trichoderma reesei, CBH I (Cel7A) and EG II (Cel5A) and their catalytic domains on steam pretreated softwood (SPS) and lignin using tritium labeled enzymes. Both CBH I and its catalytic domain exhibited a higher affinity to SPS than EG II or its catalytic domain. Removal of cellulose binding domain decreased markedly the binding efficiency. Significant amounts of CBH I and EG II also bound to isolated lignin. Surprisingly, the catalytic domains of the two enzymes of T. reesei differed essentially in the adsorption to isolated lignin. The catalytic domain of EG II was able to adsorb to alkaline isolated lignin with a high affinity, whereas the catalytic domain of CBH I did not adsorb to any of the lignins tested. The results indicate that the cellulose binding domain has a significant role in the unspecific binding of cellulases to lignin.

Adsorption↗