Bimodification of polyacrylonitrile (PAN) fibers

A new technique for the modification of PAN fibers has evolved, in which the starting precursor material is impregnated with an aliphatic carboxylic acid, as well as KMnO₄. The bimodification of PAN, attempted by us for the first time, is aimed at achieving dual advantages in plasticization effect, as well as in a catalytic effect in a single treatment. The unmodified, unimodified, and bimodified precursors have been characterized for their mechanical, thermal, and physical behavior during various stages of processing to carbon fibers. These results are discussed in detail. The study further shows an 18% improvement in the mechanical properties of carbon fibers, prepared from bimodified precursor, as compared to that of unmodified precursor. One of the reasons for such improvement is the lowering in diameter of PAN fibers and in the resulting carbon fibers. © 1993 John Wiley & Sons, Inc.     

Inhibitory effects of Estracyt on R-3327 rat prostatic carcinoma

Estracyt (estramustine phosphate) injected intraperitoneally, 100 mg, per Kg. three days a week for four weeks, retarded growth of the R-3327 tumor in intact rats and in orchiectomized rats given androgen. The growth inhibition was accomplished by reduction of tumor deoxyribonucleic acid concentration and of the activities of acid phosphatase, leucine aminopeptidase, and other hydrolases. Histologic examination revealed cellular necrosis particularly prominent in the orchiectomized, androgen-treated rats. Estracyt did not affect the uptake of 65-Zn in the tumors but markedly reduced the high uptake in the dorsolateral prostate. There was no accumulation of 3H or 14C in the tumors after intravenous administration of 3H, 14C-labeled Estracyt, but the isotope concentrations decreased much in the same way as they decreased in the dorsolateral prostate. The isotopes were retained in the ventral prostate, where their concentrations were approximately twenty times higher than those in the muscle four hours after injection. The results demonstrate the value of the R-3327 tumor in the evaluation of drugs of potential clinical use for the treatment of prostatic cancer. The results also show that Estracyt has an antitumor effect which is not dependent on the antigonadotropic action of the drug.     

Electrical transport properties of polycrystalline HgTe films grown from mercury-rich HgTe

Measurements of the Hall coefficient and the d.c. conductivity were made on polycrystalline films prepared from mercury-rich HgTe. It was found that, in addition to grain boundary potential barrier scattering, the contribution of ionized impurity scattering is also quite significant. The effect of excess mercury in HgTe is to increase the mobility and to reduce compensating effects.     

N.m.r. study of copolymer of styrene with methyl methacrylate prepared in presence of zinc chloride

In the n.m.r. spectrum of a styrene (Sty)-methyl methacrylate (MMA) copolymer prepared in presence of zinc chloride at 60°C the phenyl protons of the styrene unit appeared as one peak at 3τ, the methoxy protons of methyl methacrylate unit appeared as three peaks at 6.4–6.8τ, 7.1–7.3τ and 7.5τ. The position of these peaks indicated an alternate copolymer. This was further confirmed by estimation of copolymer composition from n.m.r. spectrum and element analysis. The value of ‘σ’ which is the probability of alternating MMA and Sty units having same configuration was also determined and found to be 0.865 ±0.006. It was found that the value of ‘σ’ was a direct function of concentration of zinc chloride.     

Eyedness

Study of the activities of hyaluronidase, lactate dehydrogenase isoenzyme-X and the dehydrogenases of sorbitol, alpha-glycerophosphate, glucose-6-phosphate, malate, glyceraldehyde-3-phosphate and isocitrate in the testes of mice of different ages showed that the changes were correlated with the stages of spermatogenic cell differentiation. The first 4 enzymes had activities which were low in newborn mice and high in adults; this pattern was reversed for the other enzymes.