DDT absorption and chylomicron transport in rat

Male rats were fed 100 nM dichlorodiphenyltrichloroethane-¹⁴C in oil by gastric tube. Recovery of dichlorodiphenyltrichloroethane-¹⁴C in thoracic duct lymph was 60% in 12 hr. Lymph dichlorodiphenyltrichloroethane-¹⁴C (97%) occurred in lipoproteins of d<1.006, designated chylomicrons. Mechanical separation of chylomicron triglyceride core (labeled with triglyceride-³H) from chylomicron membrane (labeled with phospholipid-³²P) showed that 97% dichlorodiphenyltrichloroethane-¹⁴C was present in triglyceride core. To investigate possible association of plasma clearance of the two core lipids, rats were pulse injected with chylomicrons, doubly labeled with triglyceride-³H and dichlorodiphenyltrichloroethane-¹⁴C. The decay of dichlorodiphenyltrichloroethane-¹⁴C in sequential serum samples was rapid (T^1/2=2 min) and was independent of triglyceride-³H decay. In tissues removed 14 min after injection of chylomicrons, 30% administered dichlorodiphenyltrichloroethane-¹⁴C was found in liver but only 1% in adipose tissue. In hepatectomized (eviscerated) rats, the decay of serum dichlorodiphenyltrichloroethane-¹⁴C (T^1/2=10 min) was also independent of and more rapid than triglyceride-³H decay. With sucrose density gradients, it was shown that chylomicron dichlorodiphenyltrichloroethane-¹⁴C transferred to higher density serum proteins in vitro and in vivo and to bovine albumin in vitro. Thus, dichlorodiphenyltrichloroethane was transported from intestine largely in the triglyderide phase of chylomicrons; disappearance of chylomicron-dichlorodiphenyltrichloroethane from the systemic circulation was rapid and partly independent of the presence of the liver and of triglyceride hydrolysis; some dichlorodiphenyltrichloroethane was transported from serum chylomicrons to albumin or other plasma proteins before tissue uptake.     

Perfecting operation of an apparatus for two-stage deasphalting of residuum with liquid propane at the Ryazan' refinery

Chemistry and Technology of Fuels and Oils -     

Hepatic damage produced by long-term alcohol consumption in well-nourished rats

A study of the effect of long-term alcohol consumption on the liver of well-nourished rats is described. Rats fed for 16 weeks on a semipurified diet supplemented with high levels of vitamins and lipotropic factors and alcohol corresponding to 35% of the total caloric intake developed marked fatty changes of the liver. Mild fatty changes were observed in pair-fed controls receiving as isoenergetic equivalent of sucrose instead of alcohol. Intracellular hyaline bodies, corresponding ultrastructurally to giant mitochondria were abundantly found in the hepatocytes of alcoholic rats, while in the controls they were not seen. Te findings in this investigation are postulated to provide further evidence that the long-term intake of alcohol exerts a direct causative role in the pathogenesis of liver damage.     

Structure development during melt spinning of linear polyethylene fibers

Apparatus has been developed for studying the development of crystallinity and orientation during the melt spinning of synthetic fibers. Tension in the fiber and temperature, diameter, and x-ray diffraction patterns are measured as a function of distance from the spinneret for a running monofilament. Measurements are presented for linear polyethylene over a range of spinning variables together with other investigations carried out on the final as-spun fibers. These data indicate that the development of crystallinity in polyethylene is controlled by a balance between increased crystallization kinetics caused by the stress in the fiber and a tendency for increased supercooling with change in any spinning variable that increases cooling rates in the fiber. The type of crystalline orientation observed, its development during the spinning process, and the changes observed with changes in spinning conditions suggest a model for the as-spun fiber structure in which varying amounts of row nucleation and twisting of lamellar, folded-chain crystal overgrowths occur depending on the spinning conditions. As-spun fiber birefringence was shown to depend primarily on the crystalline orientation. Mechanical properties correlated well with c-axis crystalline orientation function and spinline stress.     

Properties of aluminophosphate concretes containing various types of orthophosphoric acid

Conclusions The type of orthophosphoric acid has the maximum influence on the properties of corundum concretes, a lower influence on high-alumina concretes, and practically no influence on quartz-clay concretes. It is desirable to use wet-process orthophosphoric acid for refractory concretes. The excellent properties of concretes in the system A1₂O₃-SiO₂ based on this acid which is also cheaper enabled us to recommend it for preparing refractory concretes.The advantage of using H₃PO₄ of various types for corundum concretes is determined by the requirements placed on them in actual working conditions.Translated from Ogneupory, No.6, pp. 58–61, June, 1970.     

High-impact poly(ethylene terephthalate) blends

Rubbers of different kind were tested as toughening agents of poly(ethylene terephthalate) (PET), noting significant morphological and mechanical differences. In particular, good results were obtained by using an ethylene–ethyl acrylate–glycidyl methacrylate copolymer. The resulting blend evidenced good particle distribution, and the latter was related to chemical interactions between the rubber epoxy groups and PET terminal groups, including the effect of low molecular weight and polymeric amine catalysts, and to extrusion conditions. © 1995 John Wiley & Sons, Inc.