SEARCH · PubMed Health

Results for “Distillation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 1,297 records · Page 72Linked to original sources

PubMed1997

Urinary naphthols as an indicator of exposure to naphthalene.

OBJECTIVE: The relationship between exposure to naphthalene and urinary excretion of naphthols was examined. METHODS: Concentrations of naphthalene and naphthols in breathing-zone air during a workshift and 1-naphthol and 2-naphthol in urine collected after the workshift were determined for 102 male workers. Gas chromatography with a flame ionization detector (GC-FID) was used to determine the air concentration. Urine naphthols were extracted after acid hydrolysis by solid-phase extraction and separated by the GC-FID method. Naphthalene homologues in air and their metabolites in urine samples were identified by gas chromatography-mass spectrometry. RESULTS: 1-Naphthol, 2-naphthol and 1,4-naphthoquinone were identified in the urine samples. The time-weighted average concentrations of naphthalene and naphthols in the breathing-zone air showed that the exposure level of the workers was rather low. The geometric mean values were as follows: 0.77 and 0.87 mg/m3 for naphthalene, 0.016 and 0.034 mg/m3 for 1-naphthol, 0.012 and 0.067 mg/m3 for 2-naphthol during tar distillation and naphthalene oil distillation, respectively. The corresponding urinary concentrations of 1- and 2-naphthols were 693.1 and 264.4 micromol/mol and 264.4 and 297.7 micromol/mol creatinine, respectively. The correlation coefficients between the naphthol concentrations in urine and the breathing-zone air concentrations of naphthalene were statistically significant, varying in the range of 0.64--0.75 for 1-naphthol and 0.70--0.82 for 2-naphthol. There was linear dependence (r = 0.76) between the summary concentration of naphthols in urine and the naphthalene concentration in air. CONCLUSIONS: Workers in tar distillation and naphthalene distillation are exposed to rather low concentrations of naphthalene and methylated naphthalenes and naphthols. Naphthols and 1,4-naphthoquinone identified in the urine appear to be the products of the hydroxylation of naphthalene present in the breathing-zone air. These findings suggest that the summary concentration of naphthols in urine can be used as a biomarker for naphthalene exposure.

Adolescent↗

PubMed2000

Antifungal activity of Curcuma longa grown in Thailand.

Curcuma longa Linn. or turmeric (Zingiberaceae) is a medicinal plant widely used and cultivated in tropical regions. According to Thai traditional texts, fresh and dried rhizomes are used as peptic ulcer treatment, carminatives, wound treatment and anti-inflammatory agent. Using hydro distillation, 1.88% and 7.02% (v/w) volatile oils were extracted from fresh and dried rhizomes, respectively, and 6.95% (w/w)crude curcuminoids were extracted from dried rhizomes. Dried powder was extracted with 95% ethanol and yielded 29.52% (w/w) crude ethanol extract composed of curcumin (11.6%), demethoxycurcumin (10.32%) and bisdemethoxycurcumin (10.77%). These extracts were tested for antifungal activity by agar disc diffusion method against 29 clinical strains of dermatophytes. It was found that crude ethanol extract exhibited an inhibition zone range of 6.1 to 26.0 mm. There was no inhibition activity from crude curcuminoids while curcumin, demethoxycurcumin and bisdemethoxycutcumin gave different inhibition zone diameters ranging from 6.1 to 16.0 mm. Although antifungal activity of undiluted freshly distilled oil and 18-month-old oil revealed some differences, the inhibition zone diameters for both extracts varied within 26.1 to 46.0 mm. With 200 mg/ml ketoconazole, the activities of the standard agent were similar to the oil, both freshly distilled and 18-month-old, but were significantly different from those of curcuminoid compounds and crude ethanol extracts (p < 0.01). Turmeric oil was also tested for its minimum inhibitory concentration (MIC) by broth dilution method. The MICs of freshly distilled and 18-month-old oils were 7.8 and 7.2 mg/ml respectively.

Antifungal Agents↗

PubMedDate not supplied

Effect of different artificial aging conditions on ceramic-composite bond strength.

PURPOSE: The purpose of this study was to evaluate the influence of different storage conditions on the bond strength of adhesive bonding systems to yttria-partially stabilized zirconia ceramic. MATERIALS AND METHODS: Acrylic glass tubes filled with composite resin were bonded to ceramic disks. After sandblasting and ultrasonic cleansing of the ceramic samples, they were bonded using five bonding methods. Samples were tested for tensile bond strength following five different storage conditions: 3 days in distilled water at 37 degrees C, 31 days in distilled water at 37 degrees C, 37,500 thermocycles between 5 and 55 degrees C within 31 days, 150 days in distilled water at 37 degrees C, and 150 days in distilled water with 37,500 thermocycles performed at intervals. RESULTS: Mean resin bond strength values ranged from 7.7 to 41.9 MPa. There were statistically significant differences among groups, as revealed by the Kruskal-Wallis test. Some storage conditions influenced the resin bond strength statistically significantly, as revealed by the Wilcoxon rank sum test modified by Bonferroni-Holm. CONCLUSION: Thermocycling had a much higher impact on the durability of the resin bond strength to zirconia ceramic than did water storage at a constant temperature.

Adhesiveness↗

PubMed1976

Pseudomonas cepacia in an intensive care nursery.

A small epidemic of Pseudomonas cepacia infection in an intensive care nursery was associated with contaminated, distilled water. This appeared to have occurred because of a leak in the distiller, contaminating its effluent. The distilled water was not subsequently sterilized, nor were the bottles used to distribute it. The epidemic was promptly terminated by substitution of sterile, distilled water distributed in sterile containers. Both professional and nonprofessional hospital personnel failed to oversee the appropriateness of handling of patient care materials.

Aged↗

PubMed1992

Dentin surface treatment and shear bond strength of a light-cured glass ionomer.

This study evaluated the effect of dentin surface treatment with polyacrylic acid on the shear bond strength of Fuji Lining LC light-cured glass ionomer lining cement (GIC). A total of 40 human, noncarious extracted permanent molars stored in distilled water were used. A flat buccal dentin surface was ground wet on 600-grit silicon carbide paper. The teeth were then randomly distributed into four groups of 10 teeth each: Group 1: dentin rinsed with distilled water, dried with oil-free compressed air, placement of cylindrical GIC samples and sheared at 15 minutes post-curing. Group 2: same as group 1, but sheared 7 days post-curing. Group 3: dentin treated with GC Conditioner for 10 seconds, rinsed with distilled water, dried with oil-free compressed air, placement of the GIC and sheared 15 minutes post-curing. Group 4: same as group 3, but sheared 7 days post-curing. The GIC was mixed in a 1:1 powder-liquid ratio. The samples were stored in distilled water until sheared with an Instron. The results revealed that dentin surface treatment with the polyacrylic acid significantly increased the shear bond strength to dentin when tested at 7 days post-curing.

Acid Etching, Dental↗

PubMed1992

Consumer vinegar test for determining calcium disintegration.

A consumer test and standardized methods were compared for measuring the disintegration of calcium tablets, and the disintegration results were compared with results of dissolution testing to determine the ability of the consumer test of disintegration to predict bioavailability of calcium. Disintegration of 17 calcium supplement products, in tablet form, was studied in Simulated Gastric Fluid Test Solution, USP, without pepsin (GF), in distilled water, and in white distilled vinegar. For disintegration testing with GF and with distilled water, six tablets of each product were placed in an apparatus and immersed in the solution at 37 degrees C for 60 minutes. Six tablets of each product were tested in 200 mL of vinegar at room temperature for 30 minutes. Disintegration was determined by visual observation. Seven products were tested for dissolution in GF or water. Three samples of each product were tested at intervals over 120 minutes for calcium content. Results of testing with an ion-selective electrode were converted to milligrams and compared with the calcium content of the tablets (as claimed on the package label). The mean disintegration times of various calcium products in vinegar ranged from 1.8 to greater than 30 minutes. The mean time in distilled water and GF ranged from 1.6 to greater than 60 minutes and from 1.0 to greater than 60 minutes, respectively. Results were in agreement in 87% to 93% of cases between the consumer vinegar test and the standardized disintegration test methods, a significant correlation. No correlation was found between disintegration time and the extent of dissolution. The disintegration and dissolution of commercially available calcium tablets was highly variable.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗

PubMed2005

[Influence of storage methods on microtensile bond strength of dentin adhesive system].

PURPOSE: To compare the effects of teeth stored with different methods and different durations of storage on the microtensile bond strength of the dentin adhesive system Single Bond. METHODS: 30 human first premolars were stored immediately after extraction in one of five commonly used methods respectively: 0.02% distilled water and thymol, 10% formalin, 1% chloramine, distilled water at 4 degrees C and were refrigerated at -20 degrees C. After 10 days, 90 days, the dentin adhesive system Single Bond and composite Z250 were applied to superficial occlusal flat dentin according to the manufacturers' instructions and microtensile bond strength measurements were evaluated, freshly extracted teeth being used as control. Stero-microscope and scanning electronic microscope were used to evaluate the fracture modes of the microtensile bond strength specimens. Two-way ANOVA was used for analysis of the microtensile bond strengths among different groups. RESULTS: The results showed that there was significant difference among five tooth storage methods on the microtensile bond strength of dentin bonding agent (P=0.01). Compared with freshly extracted teeth, two of five storage methods/media, 0.02% distilled water and thymol at 4 degrees C (P=0.008) and distilled water at 4 degrees C (P=0.024), resulted in significantly lower microtensile bond strengths. The duration of teeth storage had no effect on the microtensile bond strength of dentin bonding agent (P=0.279). The interaction of two factors was significant (P=0.000). Stero-microscope and SEM examination indicated that all fracture modes were adhesive failures. CONCLUSIONS: From this study, it can be concluded that the teeth storage methods/media can influence the microtensile bond strength of Single Bond adhesive system. If sufficient numbers of freshly extracted teeth are not available for bond strength test, the freezing teeth at -20 degrees C and teeth stored in 1% chloramine at 4 degrees C are preferred .

Dental Bonding↗

PubMed2004

[Influence of extraction methods on the composition of essential oils].

The aim of this work is to demonstrate our results on comparison of composition of essential oil fractions obtained by traditional steam distillation and supercritical fluid extraction. The plant materials for the various extraction methods were selected from the Lamiaceae, Apiaceae and Asteraceae families. For the supercritical fluid extraction (SFE) carbon dioxide was used as supercritical solvent. The extracts were collected by stage wise precipitation in two separators. The waxy product and extract rich in essential oil were collected in the 1st and in the 2nd separator respectively. The traditional water steam distillation (SD) was carried out in the special apparatus of the Hungarian Pharmacopoea (7th ed.). GC analysis was carried out on capillary silica fused columns coated with DB-1701 and the specific chiral columns coated with Rt-beta DEX m or Rt-beta DEX sm. Comparing the composition of steam distilled oils with that of volatile SFE fractions the following general characteristics were established. The SFE fractions were richer in monoterpene-esters and poorer in alcohols than the traditional essential oils (clary sage, lavander, moldavian dragonhead). Regarding the distribution of the monoterpene and sesquiterpene compounds, the SFE fractions contained sesquiterpenes in higher percentage than the distilled oils (Salvia fruticosa). Furthermore, the proportion of sesquiterpenes increased in SFE fractions collected successively with time (Salvia officinalis) similar to the ratio of oxygenated monoterpenes to monoterpene hydrocarbons (Rosmarinus officinalis). The phtalides of lovage (Satureja hortensis) did not show regular change during the supercritical extraction. In other cases it was verified that part of the mono- and sesquiterpenes were present originally in bound form (glycosides) in plants. Thus they appeared only in essential oil fractions after previous acidic treatment (Thymus, Origanum, Satureja species). During the super-critical extraction the azulenogene sesquiterpene lactones did not transform to azulenes (chamomile, yarrow), but SFE fractions of some Asteraceae plants contained sesquiterpene-gamma-lactones of unchanged structure.

Apiaceae↗

PubMed2005

[The new progress of the study about volatile oil of the angelica].

To summarize the new progress of the study about volatile oil of the angelica, including the distillable methods, the analysis of the chemical components, the pharmacological effects and the clinical applications. We tracked and searched the correlative references and study reports about volatile oil of the angelica in CNKI data base(1994-2004) and Medline data base (1997-2004). We summarized and compared the different distillable methods of volatile oil of the angelica, meanwhile we summarized many study reports about the analysis of the chemical components of volatile oil of the angelica and it's pharmacological effects, including the toxicity of the volatile oil and it's effects on the uterus smooth muscle, cardiovascular system, respiratory system, central nerve system and immune system. Finally we summarized the clinical application of the volatile oil of the angelica. There are three distillable methods of volatile oil of the angelica . The harvest efficiency of volatile oil is different with different distillable methods. The chemical components are very complicated and the new chemical components are separated and identified. The volatile oil has bidirectional effects on the uterus smooth muscle. It can inhibit the contraction of the uterus smooth muscle induced by different mechanisms. Meanwhile it can depress the blood pressure and ameliorate the cardiac ischemia. The volatile oil can resist the arrhythmia and asthma, restrain the central system, improve the immune function. Nowadays the volatile oil of the angelica is applied to therapy the dysmenorrhea and disorder of the catamenia. The chemical components of the volatile oil of the angelica are very complicated, moreover the pharmacological effects of the volatile oil are comprehensive. People make the new progress of the study about volatile oil of the angelica.

4-Butyrolactone↗

PubMed1990

[Modified microdiffusion method for fluoride analysis of foodstuffs].

In fluoride analysis, there are two procedures for the determination of fluoride depending on nature of samples. One procedure directly can determine fluoride contents by fluoride ion electrode, dissociating fluoride from the sample with the acid (perchloric acid). The other procedure needs to separate fluoride from biological sample using steam-distillation or micro-diffusion method, and then the determination by means of fluoride ion electrode can be applied. In this study, we applied a modified microdiffusion method by Hinoide (1990) for its availability in different temperatures and reaction time, and then estimated to determine fluoride contents of Shrimp (Sakura-shrimp) as a biological sample by this method. It is also very important to determine fluoride contents of foodstuffs and biological samples with regard to bioavailability of fluoride in vivo. The results were as follows: 1. Using the modified microdiffusion method, the fluoride recovery rate attained more than 95% in the range of 0.1-10 micrograms fluoride from a standard solution under the experimental condition of 60 degrees C and 90 degrees C of reaction temperatures and 60, 90 and 120 minutes of reaction time. 2. For the sample of shrimp, fluoride contents analyzed by means of the modified micro-diffusion and steam-distillation methods showed almost similar values, although the fluoride contents by steam-distillation method revealed relatively lower value. The difference might be derived from a loss of fluoride in ashing the sample before applying the steam-distillation method. The modified microdiffusion method used in this experiment can be utilized routinely and precisely in fluoride analysis for small amounts of biological sample.

Animals↗

PubMed1985

[Experimental studies on hemolysis in transurethral interventions].

The question whether distilled water can be used as irrigating fluid for the transurethral electroresection has repeatedly given occasion for discussion. Price and better visibility when resecting speak in favour of its application. Haemolytic alterations, however, might occur and seem to make its application dangerous. Our own experiments in animals show that especially blood haemolised through distilled water in the bladder (a mixture of aqua dest. and haemolised erythrocytes) has a strong haemolytic effect. Intravenous instillation of distilled water leads to haemolytic processes as well, which, however, are weaker than those occurring after instillation of erythrocytes haemolised through distilled water. Solutions of Sorbitol and Manitol (e.g. Purisole) had no measurable haemolytic effect. On the basis of our examinations we can retain the fact that with massive absorption of already haemolised erythrocytes, dangerous alterations, occur. Such alterations depend on duration of resection, technique of resection and pressure conditions (use of low pressure irrigation resectoscopes or trocar irrigation). For the experienced urologic surgeon these factors might be less relevant, for the beginner, however, who might not take into consideration the facts mentioned, results could be disastrous. The use of Sorbitol- and Manitol-fluids during TUR, prevents haemolytic incidents with certainty.

Animals↗

PubMed1989

[Study of the creep of glass-ionomer cements].

The creep and recovery of microspecimens of glass-ionomer cements was studied using a tortional creep apparatus. The purpose was to investigate viscoelastic behavior in a low stress that might result from normal chewing forces. Small stress (2,048 MPa), below the composite resin's proportional limit, was maintained for 3 h and after the stress was released. Recovery was followed for 50 h. The measurements were made on specimens: aged 24 h stored dry at 21 degrees C, aged 24 h stored in distilled water at 21 degrees C, aged 24 h stored in distilled water at 37 degrees C, aged 1 week stored in distilled water at 37 degrees C. The glass-ionomer cements exhibited linear viscoelastic behavior at low deformations. The materials did not recover their original shape after 50 h after the stress was removed. The least amount of creep and permanent deformation exhibited the specimens aged for 1 week in distilled water at 37 degrees C. The influence of dehydration was apparent on specimens measured dry at 21 degrees C. They exhibited the greatest amount of creep and permanent deformation.

Dental Cements↗

PubMed1978

The effects of DL-5-hydroxytryptophan on ethanol consumption by rats.

Rats were offered access to either distilled water or a 12% v/v solution of ethanol as their only fluid during a one hour period daily. After daily fluid consumption has achieved a stable baseline, either distilled water or DL-5-hydroxytryptophan (5HTP) in doses of 50, 100 or 200 mg/kg was injected intraperitoneally one hour prior to the drinking session. While each of the three doses of 5HTP caused a significant reduction in ethanol intake, distilled water had no effect. Water consumption was unaffected by 5HTP or distilled water injections. Varying the pretreatment interval from 0.5, 1, 4 to 8 hours for the 100 mg/kg 5HTP dose resulted in a significant decrease in ethanol consumption at 0.5 and 1 hour pretreatment intervals only. In approximately 25% of the rats tested, 5HTP resulted in a prolonged rejection of ethanol so severe that it resulted in death. Selected rats offered water during this ethanol rejection period readily drank it and survived.

5-Hydroxytryptophan↗

PubMed1979

[Determination of sorbic acid, its salts and salicylic acid in food products of animal origin].

A foreign method for quantitative assay of sorbic acid and natrium sorbate in food stuff of plant origin was applied by the authors for food stuffs of animal origin. The conservant of the food stuff was isolated by water vapour distillation. Sorbic acid and natrium sorbate assay was performed on part of the distillate colorimetrically at wave length lambda--532 nm. The method proved highly sensitive (2 gammas and 94% reproduction). It can be used in conservant assay of various fish assortments, canned food, roe and some types of cheese. A qualitative method for proving the presence of salicylic acid is proposed, using water vapour distillation of the biological material. Part of the distillate produced is treated directly by 1% ferriammonium sulfate water solution. A violet tint of the solution proves the presence of salicylic acid in the product studied.

Animals↗

PubMed1978

Antitumor activity of N-trifuloroacetyladriamycin-14-valerate.

The antitumor activity and toxicity of N-trifluoroacetyladriamycin-14-valerate (AD 32) dissolved in 10% Tween 80 in distilled water were compared to those of adriamycin dissolved in distilled water in 10% Tween 80 in distilled water, in mice bearing L1210 leukemia, P388 leukemia, Gross leukemia, and solid Sarcoma 180. Treatments were performed ip or iv according to different schedules. The antitumor-activity of AD 32 was not superior to that of adriamycin. The antitumor activity of adriamycin dissolved in aqueous solution of Tween 80 was higher than that of adriamycin dissolved in distilled water after after iv treatment.

Animals↗

PubMedDate not supplied

Method for determination of organohalogen pesticide residues in vegetable oil refinery by-products.

A method using gel permeation and Florisil column chromatographic cleanup techniques is described for determination of residues of nonpolar organohalogen pesticides and pesticide alteration products in vegetable oils and their refinery by-products. Supplemental Florisil separation and alkali cleanup techniques are used to facilitate determinations. Residues are determined with a 63Ni electron capture gas chromatographic detection system used in conjunction with 3 different gas chromatographic columns. Residue identities are confirmed by gas chromatography-mass spectrometry. Recoveries of 7 organohalogen pesticides, ranging from 90 to 103%, were determined by the supplemental Florisil separation technique to augment previously reported recovery data determined for initial GPC and Florisil cleanup steps. Soybean, peanut, and cottonseed deodorizer distillates and crude and refined oil, as well as additional refinery by-products, were analyzed. Nine to 13 organohalogen residues ranging from 0.5 to 6.3 ppm were determined in the 2 soybean deodorizer distillate samples used to develop and test the method. Identities of residues present at greater than or equal to 0.3 ppm were confirmed by gas chromatography-mass spectrometry. An intralaboratory trial of the method provided additional recovery and residue determination data as follows: Recoveries ranging from 102 to 116% were obtained for 4 pesticides added to peanut oil deodorizer distillate. Residues determined in 1 soybean deodorizer distillate sample supported previously obtained data for this sample.

Chromatography, Gas↗

PubMed1982

The influence of ascorbic acid on the growth of solid tumors in mice and on tumor control by X-irradiation.

Swiss mice drank either distilled water or 0.1% ascorbic acid in distilled water for one week prior to and during the experiments. Solid tumors were induced by injecting Ehrlich ascites tumor cells i.m. into the hind limb of Swiss male and female mice. It was found that the tumor growth was significantly faster in the mice that were drinking distilled water. Beginning two days after tumor cell injection, the tumor bearing limbs were irradiated every 24 h as follows: a) 6 exposures of 400 R, 500 R, 600 R, or 700 R each, b) 10 exposures of 400 R each, and c) 11 exposures of 400 R each. Our results indicated that when 6 exposures of 700 R each were given every 24 h to mice drinking distilled water, about 80-85% tumor control was achieved; the percent tumor cure was even better in mice drinking ascorbic acid in water than in mice drinking water.

Animals↗

PubMed1980

Effect of the angiotensin converting enzyme inhibitor, captopril, on NaCl appetite of rats.

Dietary administration of the angiotensin converting enzyme inhibitor, captopril (0.70 g/kg of food), to female rats for 1 week was accompanied by a spontaneous appetite for 0.25, 0.30 or 0.35 M NaCl solution when choice was offered between any one of them and distilled water to drink. An additional experiment was performed to determine the NaCl preference threshold concentration for each group. Control and treated rats were offered choice between two drinking bottles containing distilled water and a NaCl solution, respectively. The concentration of the latter varied from 0.0006 to 0.350 M/l. Control rats could detect the difference between water and NaCl solution at a concentration of 0.030 M/l, whereas captopril-treated rats detected the difference at the lowest concentration offered, i.e., 0.0006 M/l. Captopril-treated rats also preferred 5% glucose solution to distilled water, as did untreated controls. Similar results were observed for 0.25% saccharin. No difference between groups was observed when choice was offered between distilled water and dilute solutions of HCl. Thus, a NaCl appetite developed within 1 week of treatment with captopril. The appetite was accompanied by an ability to detect NaCl at a 50-fold lower concentration than that of the control group. Administration of captopril was also accompanied by an appetite for glucose and saccharin but not for HCl.

Animals↗