Polychlorierte Biphenyle (PCB) im menschlichen Fettgewebe

Zusammenfassung Die vorliegende Arbeit beschreibt die Kontamination menschlichen Fettgewebes mit den sechs als Indikator-Kongeneren bekannten Polychlorbiphenylen, mit PCB Nr. 49 und den Mischinducern PCB Nr. 156, 170 und 189. Die niedrig chlorierten Biphenyle Nr. 28, 49 und 52 konnten nicht nachgewiesen werden, die Konzentration von PCB Nr. 101 betrug im Mittel 9 g/kg. Die Gehalte von PCB Nr. 138, 153 und 180 lagen geringfügig unter den von der DFG angegebenen Werten. Der Anteil der Mischinducer Nr. 138, 156, 170 und 189 machte nahezu 40% der Gesamtbelastung aus. Die Höhe der PCB-Kontamnation des Fettgewebes war altersabhängig, wobei für die Gruppe der 61-bis 70jährigen mit Ausnahme von PCB Nr. 101 ein sprunghafter Anstieg der Konzentrationen beobachtet wurde.

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Polychlorinated biphenyls in human adipose tissue

Summary This study describes the contamination of human adipose tissue with six selected polychlorinated biphenyls (PCB) known as indicator congeners, with PCB no. 49 and the mixed inducer PCB nos. 156, 170, and 189. The low chlorinated biphenyls nos. 28, 49, and 52 could not be found in the tissue samples, while the average concentration of PCB no. 101 was 9.0 g/kg. The content of PCB nos. 138, 153, and 180 was slightly below the values published by the Deutsche Forschungsgemeinschaft (DFG). The mixed inducer nos. 138, 156, 170, and 180 amounted to approximately 40% of all the PCBs measured. The PCB contamination was positively correlated with age: for the age group 61–70 years, with the exception of PCB no. 101, a distinct increase in the concentrations could be observed.

     

Calculation of countercurrent separation processes—III. Computation of two interlinked columns.

The relaxation procedure is used for solution of two interlinked distillation columns. Both approaches-sequential iterative method and the block relaxation technique are compared. A new algorithm making use of simultaneous solution of all equations is proposed.     

Improvement of vascular dysfunction and blood lipids of insulin-resistant rats by a marine oil-based phytosterol compound

The syndrome that is characterized by obesity, insulin resistance, and hyperlipidemia is increasingly prevalent in all prosperous societies. It is now recognized as a major contributor to cardiovascular disease. Vascular dysfunction in the form of hypercontractility and impaired nitric oxide-mediated relaxation is a significant component of cardiovascular disease, predisposing to ischemic events. The JCR:LA-cp strain of rats exhibits all major aspects of the obesity/insulin resistance syndrome, including vascular dysfunction and ischemic lesions of the heart. Dietary lipid intake may have a marked effect on plasma lipid levels and, potentially, on vascular disease. We have investigated the effects of a novel preparation, ONC101 (a phytosterol esterified with fish oil), on plasma lipids and vascular function in the insulin-resistant JCR:LA-cp rat. Treatment of obese male rats with ONC101 from 8 to 12 wk of age resulted in no change in plasma lipid concentrations at 0.5 g/kg body weight. At the higher dose of 2.6 g/kg, plasma TG fell 50% (1.26 vs. 2.59 mmol/L, P<0.002) and cholesterol esters were significantly reduced (1.34 vs. 1.61 mmol/l, P<0.002). Food intake and body weights were unaffected by ONC101 treatment. At the low dose of 86 mg/kg, the hypercontractility of aortic rings in response to phenylephrine was normalized and the relaxant response to acetylcholine was significantly improved. The results indicate that ONC101 at high doses has significant hypolipidemic effects and, at very low doses, has beneficial effects on endothelial and vascular smooth muscle cell function. Deceased, June 22, 2001.     

Flame‐retardant effect of polyaniline coating deposited on cellulose fibers

Filtration paper was coated with a thin polyaniline film. The content of conducting polymer was 8.2 and 6.3 wt % for polyaniline hydrochloride and polyaniline base, respectively. After burning, the coated material retains the original fibrilar morphology of cellulose. The polyaniline coating converts to solid carbonaceous products. The resulting structure prevents the formation of gaseous carbon oxides by restricting the access of oxygen to cellulose. While the ash from the uncoated paper after burning is 0.005 wt %, the microtubular residue of polyaniline‐coated paper is 16–24 wt % of the original mass. The flame‐retardant performance of polyaniline and poly(1,4‐phenylenediamine) coatings was comparable both for the protonated forms and the corresponding bases. The conversion of polyaniline‐coated cellulose fibers to solid pyrolytic products was characterized by FTIR and Raman spectroscopies. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2347–2354, 2005     

Streptomycetes cultured on glass beads: Sample preparation for SEM

We demonstrate the preparation of samples of streptomycetes (Streptomyces coelicolor, S. aureofaciens) cultured on glass beads (balotina) for scanning electron microscopy. The main trick of the method consists in immobilization of glass beads with low-melting agarose. The samples are then fixed in OsO(4) vapors followed by dehydration in vapors of absolute ethanol. No air-to-liquid transition during the sample preparation occurs. Consequently, whole cell cycle of streptomycetes in the term of mycelial morphology can readily be studied by this method.     

Eulerian-Lagrangian model for traffic dynamics and its impact on operational ventilation of road tunnels

This contribution deals with a computational Eulerian-Lagrangian model that simulates movement of cars inside a road tunnel and its impact on operational ventilation. The model simulates moving cars as discrete objects that “fly” through the tunnel. The objects are treated with a Lagrangian momentum equation and their velocity is solved along their trajectories that are determined by the shape of the roadway. The flow of the ambient air is solved with a commercial CFD code StarCD. Due to drag force, the cars virtually change their velocity, but the latter is continuously re-set to its original value. The momentum equation for the continuous phase contains an additional source term that results from the net efflux of momentum of cars when they enter and leave a particular control volume of the solution domain. The model by Jicha et al. (Int. J. Environ. Monit. Asses. 65 (2000) 343) can simulate cars moving at different speeds and traffic rates in individual traffic lanes. As a result we obtain flow rate generated by moving vehicles as a function of traffic speed and traffic rates. Turbulence was modelled using standard k-ε model with three different formulas for extra sources of the kinetic energy of turbulence that account for additional turbulence generated by moving vehicles. The traffic-induced turbulence shows a non-negligible effect on the total flow rate inside the tunnel. The model was validated with experimental data from Chen et al. (Int. J. Wind Eng. Ind. Aerod. 73 (1998) 99), where the small-scale tunnel 1:20 was investigated. The experiments were carried out with a moving belt carrying small car-like objects. The tunnel length was 20 m, the height 36.5 cm and the tunnel had two parallel lanes. Several traffic densities and speeds were simulated, namely 10,000, 20,000 and 30,000 cars/h per lane with speeds of 20 km/h and 40 km/h.     

Simplification of separation of the reaction mixture after transesterification of vegetable oil

A heterogeneous reaction mixture is formed by transesterification of vegetable oils. The reaction mixture contains mainly methyl esters of higher fatty acids and glycerol. From this mixture, biodiesel is gained by spontaneous sedimentation in the gravitational field. The sedimentation can be considerably accelerated by controlled addition of water. It was found that addition of small amounts of water to the crude reaction mixture significantly affected the mixture, and substantial changes in the speed of the separation took place. Considerable differences in the composition and quality of the ester and glycerol phases occurred. The optical properties (transmittance and refractive indices) of the heterogeneous reaction mixture are changed after addition of water; this change can be observed spectrophotometrically. This method is applicable to all types of vegetable oils including waste frying oils.