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At least 487 records · Page 27Linked to original sources
PubMed2005

[Comparison of supercritical fluid extraction and steam distillation methods for the extraction of essential oils from Schizonepeta tenuifolia Briq].

Essential oil was extracted from Schizonepeta tenuifolia Briq. by supercritical fluid extraction (SFE) and steam distillation (SD). The components extracted were determined by gas chromatography with area normalization method and identified by gas chromatography-mass spectrometry (GC-MS). The optimal chromatographic conditions were: capillary column, SE-54 (30 m x 0.25 mm i.d., 0.25 microm); column temperature, 50 degrees C (3 min) --> (5 degrees c/min) 180 degrees C (2 min --> (10 degrees C/ min) 260 degrees C 50 min); split injection, split ratio 1: 50; injector temperature, 280 degrees C. Fifty-four components were identified for the essential oils extracted by SFE, and its main components were found to be pulegone, menthone, linoleic acid chloride etc. Thirty-nine components were identified for the essential oil obtained by SD, and its main components were found to be pulegone, menthone, limonene etc. The SFE method is better than the SD method in reliability stability and reproducibility, and is thus well suitable for similar applications involving for extraction of other traditional Chinese herbal medicines.

Chromatography, Supercritical Fluid↗
PubMed1986

Factor VIII: C (FVIII: C) recovery and half-life after infusion of steam-treated high purity factor VIII concentrate in severe hemophilia A--comparison of one-stage assay, two-stage assay and a chromogenic substrate assay.

Factor VIII:C recovery and half-life was measured in 16 hemophilia A patients under comprehensively standardized conditions. Each patient received the same lot of a steam-treated high purity FVIII concentrate at a dose of 19-33 U/kg body weight. A comparison was made between the one-stage assay, the two-stage assay and a chromogenic substrate test for FVIII:C determination using a FXa-sensitive chromogenic substrate. Factor VIII:C potency of the administered FVIII concentrate was measured using calibration curves derived from a concentrate standard and FVIII:C plasma levels were read from calibration curves derived from a plasma standard. The chromogenic assay showed a good reproducibility at FVIII:C levels between 0.015 and 0.50 U/ml. The FVIII:C recoveries calculated from the results of the one-stage assay, the two-stage assay and the chromogenic substrate test were 109 +/- 20, 92 +/- 14 and 81 +/- 11% (mean +/- SD), respectively. The elimination half-lives of FVIII:C were calculated by non-linear least square analysis using a modified computerized Gauss-Newton algorithm. The half-lives calculated from the FVIII:C plasma levels measured by the one-stage assay, the two-stage assay and the chromogenic test were 23.8 +/- 6.4, 22.2 +/- 5.7 and 17.1 +/- 4.8 h (mean +/- SD), respectively. No previous study has reported such long half-life values. Our findings indicate that measurements of recoveries and half-lives by the chromogenic FVIII:C assay and by computerized non-linear least square analysis allow the possibility of individualized FVIII replacement therapy.

Adolescent↗
PubMed1979

Determination of crude protein in animal feeds, using block digestion followed by steam distillation: collaborative study.

A method consisting of digesting animal feeds in a block digestor and determining ammonia by steam distillation followed by titration has been evaluated and compared with the official final action Kjeldahl method, 7.016. Fifteen laboratories analyzed 5 feed samples and lysine monohydrochloride. Statistical analysis showed that results from the 2 methods were comparable. The distillation technique has been adopted as official first action as an alternative technique for ammonia determination from the digest of the official final action block digestor method, 7.B11.

Animal Feed↗
PubMed1995

[The change in tissue oxygenation after severe steam inhalation injury].

Tissue oxygenation was observed in dogs inflicted with steam inhalation injury in this study. Main findings were as follows: there was significant decrease in cardiac output (CO), oxygen delivery (DO2), alveolar oxygen partial pressure (PAO2), arterial oxygen partial pressure (PaO2), mixed venous oxygen partial pressure (PVO2), arterial oxygen saturation (SaO2), mixed venous oxygen saturation (SVO2), and pH (P < 0.01), and marked increase in P(A-a)O2, oxygen extraction ratio (ERO2), and arterial carbon dioxide partial pressure (PaCO2) (P < 0.01 and P < 0.05). However there was no obvious change in oxygen consumption rate (VO2) within four hours after inhalation injury. The results indicated that the tissue hypoxia was caused directly by insufficient blood perfusion and oxygen supply as well.

Animals↗
PubMed1996

[Ventilation effects of added jet air flows in different directions during expiratory phase on dogs with steam inhalation injury].

Nine dogs injured by inhaling steam were subjected to high frequency jet ventilation. Jet airflows of different directions were added during the expiratory phase, and their effects on respiration, circulation and improvment in ventilation efficiency of dogs with inhalation injury were compared, and the assessment of the mechanism of high frequency two-way jet ventilation in the trachea was made. According to the direction of added airflow during expiratory phase, the animal models were classified into three groups: Model A, the control group, without any added airflow; Model B, airflow opposite to the direction of ventilation was added; Model C, airflow of the same direction was added. The results showed: 1. Model B, with its CO2 elimination (Vco2) increased significantly (P < 0.01) and PaCO2 decreased significantly (P < 0.01), was preferable to Model A. This might be due to the reduction of dead space. 2. Model C, although there was slightly reduced anatomical and physiological dead space as compared with model A, showed worse ventilation effects. The mechanism was probably related to increase in PEEP (from 0.20 +/- 0.10 to 0.59 +/- 0.08 kPa) and FRC (from 433 +/- 59 to 504 +/- 7.0 ml). It is suggested that high frequency two-way jet ventilation is preferable for the treatment of inhalation injury with type 1 respiratory failure rather than high frequency ventilation with PEEP.

Animals↗
PubMedDate not supplied

Enhancing effect of nonionic surfactant on the inactivation of lipopolysaccharide by steam-heat treatment II.

n-alkylpolyoxyethylene surfactants (CnH2n+1O(CH2CH2O)mH; CnEm) showed a strong enhancing effect on the inactivation of lipopolysaccharide (LPS) by heat treatment over a wide range of temperatures. The effect of CnE8 (n = 10-16) was observed above the critical micelle concentration (CMC) and above the cloud point, and was influenced by the length of the alkyl chains. The efficacy of the surfactants was in the order C10E8 < C12E8, C16E8 < C14E8. However, the hydrophilic moiety seemed to have no influence. An 80-95% solution of n-butanol showed a similar effect, indicating that LPS was more effectively inactivated in the oily phase of the surfactants than in water. The effect of surfactant on the hydrodynamic diameter of LPS was the same before and after steam-heat treatment for 20 minutes at 121 degrees C. Each surfactant disaggregated LPS without alteration of the activity of LPS before the heat treatment. We consider that the surfactants interact with LPS in the region of lipid A in a manner that favors loss of the activities of LPS during heating.

Chemical Phenomena↗
PubMedDate not supplied

Determining whether a product is steam sterilizable.

The FDA has issued proposed regulations to require that manufacturer's evaluate the "steam sterilizability" of parenteral products. There are many different ways to assess sterilizability. Within a company, it is helpful to standardize the methodology used to determine whether the product should be terminally sterilized. The following is one approach to determining product sterilizability. This approach is also depicted in a flow chart (Figure 4).

Hot Temperature↗