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At least 847 records · Page 47Linked to original sources
PubMed2006

Quantitative evaluation of prion inactivation comparing steam sterilization and chemical sterilants: proposed method for test standardization.

Prions are notoriously resistant to inactivation. To prevent accidental transmission of variant Creutzfeldt-Jakob disease (vCJD), various decontamination procedures have been adopted for re-usable medical devices by the authorities of countries at risk. As the vCJD agent in humans has a wide tissue distribution, practical methods of prion decontamination urgently need to be standardized, as do other sterilization and disinfection procedures (European Committee for Standardization). This article proposes a method using a quantitative murine model, combining observations of the decrease in the infection rate, the increase in the incubation period and a simultaneously performed chemical protein fixation control. In terms of practical application, autoclaving at 134 degrees C for 18 min or 121 degrees C for 30 min, and 1N sodium hydroxide for 15 min reduced the transmission of infectivity by a factor of at least 10(6). Partial efficacy can also be identified by the methodology, particularly for liquid cold sterilants such as glutaraldehyde and peracetic acid solutions.

Animals↗
PubMed2005

Increasing the speed of relaxometry-based compartmental analysis experiments in STEAM spectroscopy.

In this work we present a method for improving the speed of spin-spin relaxation time (T2) measurements for compartmental analysis in stimulated echo localized magnetic resonance spectroscopy without reducing the sampling density. The technique uses a progressive repetition time (TR) to compensate for echo time (TE) dependent variations in saturation effects that would otherwise modulate the received signal at short TRs. The method was validated in T2 studies on 10 young healthy subjects in spectroscopic voxels localized along either the right or left Sylvian fissure (2 x 2 x 1.5 cm3, 10 ms mixing time (TM), 2048 data points, 819.2 ms acquisition time). The TR was automatically adjusted so that TR-TM-TE/2 was kept constant as the TE was incremented. Compared to long TR T2 experiments, the progressive TR technique consistently replicated the T2 relaxation times and reference signals of the tissue water compartment while reducing the data acquisition time by more than 50%. The percent error was on average less than 2% for estimates of T2 and S(0) for the tissue water, an indication that the progressive TR technique is a useful method for determining the tissue water signal for internal referencing.

Adolescent↗
PubMed1975

Chromatography of sterols, alkaloids and other drugs using steam as the mobile phase.

The chromatographic separation of steroids, alkaloids and other drugs with water vapour as the mobile phase has been studied. It is shown that this technique facilitates the analysis and reduces the retention times. The determination of the substances in low concentrations in aqueous solutions or dispersions also appears to be possible.

Alkaloids↗
PubMed2004

Steam distillation-solid-phase microextraction for the detection of Ephedra sinica in herbal preparations.

A new method involving concurrent solid-phase microextraction combined with continuous hydrodistillation of essential oil was developed. This new methodology allowed for the detection by GC-MS of very small amounts of a diagnostic peak for the authentication of Ephedra sinica, in a short period of time and using only small sample sizes. This diagnostic peak was identified as 4-vinylanisole, and elucidated from the chromatographic profile allowed for the identification of a sample as E. sinica among other species investigated in this study. To the best of our knowledge this is the first report on using continuous solid-phase microextraction coupled to hydrodistillation for the investigation of essential oil components, and the first report of 4-vinylanisole as a marker compound for E. sinica. A total of 46 collections representing 21 species of Ephedra were studied.

Automation↗
PubMed2001

Reduced inhibition of enzymatic hydrolysis of steam-pretreated softwood.

Softwood constitutes the main source of lignocellulosic material in Sweden which can be used for ethanol production from renewable resources. To make the biomass-to-ethanol process more economically feasible, it is preferable to include the sugar-rich prehydrolysate, i.e. the liquid obtained after the pretreatment step, in the enzymatic hydrolysis of the solid fraction. This study shows that the prehydrolysate inhibits cellulose conversion in the enzymatic hydrolysis step. When the prehydrolysate was included in the enzymatic hydrolysis, the cellulose conversion was reduced by up to 36%. However, this inhibition can be overcome by fermentation of the prehydrolysate prior to enzymatic hydrolysis.

Journal Article↗
PubMed2003

Identification of odor-active 3-mercapto-3-methylbutyl acetate in volatile fraction of roasted coffee brew isolated by steam distillation under reduced pressure.

In a roasted Arabica coffee brew, the potent roasty odor quality compound was identified as 3-mercapto-3-methylbutyl acetate by comparison of its Kovats gas chromatography retention index, mass spectrum, and odor quality to those of the synthetic authentic compound. 3-Mercapto-3-methylbutyl acetate has been identified for the first time in the coffee, and according to the results of the aroma extract dilution analysis, the contribution of this compound to the flavor of the roasted coffee brew varied depending on the degree of the coffee bean roasting. The concentration of this compound in the coffee brews as with 3-mercapto-3-methylbutyl formate increased with an increase in the degree of roasting. However, the slope of the amount of both esters was different, and 3-mercapto-3-methylbutyl acetate hardly increased with a low degree of roasting at more than a 21 luminosity (L)-value, but it rapidly increased when the roasting degree of the coffee beans reached the L-value of 18. These results suggested that the contribution of 3-mercapto-3-methylbutyl acetate to the overall flavor is peculiar to the flavor of the highly roasted coffee.

Acetates↗