Synthesis, Structural Characterization, and Preliminary Biological Characterization of Organotin Polyethers Derived from Hydroquinone and Substituted Hydroquinones

A variety of dibutyltin polyethers have been synthesized employing the interfacial polymerization technique. The products are polymers with degrees of polymerization ranging from 60 to 390. Infrared spectral and mass spectral results are consistent with the proposed structure. The products show good inhibition of a variety of cancer cells including those associated with bone, breast, prostrate, and lung cancers. Some also show good viral inhibition of the HSV-1 (herpes simplex) and Vaccina (small pox) viruses with those derived from electron rich hydroquinone derivative being most active. Hydroquinone-derived polymers containing electron withdrawing groups exhibit inhibition of a variety of gram positive and gram negative bacteria.     

Microstrain and Crystallite Size of Natural Microcrystalline Quartz by X-ray Line Broadening Analysis

The analysis of X-ray diffraction line profile broadening reveals the relationship between lattice microstrain and crystallite size for some microcrystalline quartz in natural quartzose rocks which crystallized slowly and statically. The mean microstrain of quartz microcrystallites increases proportionally with the reciprocal of the crystallite size and its magnitude reaches 0.18% (1.8×10⁻³) for crystallites ∼43 nm in diameter. This large lattice microstrain is ascribed to the internal pressure derived from the surface energy of the quartz microcrystallite.     

beta-carotene 15,15'-dioxygenase activity and cellular retinol-binding protein type II level are enhanced by dietary unsaturated triacylglycerols in rat intestines

The purpose of this study was to examine effects of dietary triacylglycerols on beta-carotene 15,15'-dioxygenase (EC 1.13.11.21) activity and cellular retinol-binding protein [CRBP (II)] in rats. Six groups of eight rats (7-wk old) were fed one of the following diets: standard (STD; 2.5% soybean oil), saturated (SFA; 15% hydrogenated soybean oil), monounsaturated (MUFA; 15% olive oil), polyunsaturated (PUFA; 15% soybean oil) or clofibrate (CLF; 2.5% soybean oil + 0.2% clofibrate) for 3 wk. The dioxygenase specific activities of the intestinal homogenates in the MUFA and PUFA groups fed the high fat diets were 2.4 times that of the STD group fed a low fat diet (P < 0.01), whereas the activities of the SFA and CLF groups were not significantly different from that of the STD group. The level of CRBP (II) in the intestine of the PUFA group was 1. 3-fold that of the STD group (P < 0.05), whereas there were no significant differences among the other groups. In a second experiment, the dioxygenase activity of rat intestine was followed over 3 wk of feeding the STD and PUFA diets. After the PUFA diet was consumed for 1 d, the activity was enhanced to 2.7 times the baseline level and remained thereafter at that high level, whereas the activity of the STD group remained at the low baseline level. Thus, dietary polyunsaturated triacylglycerols enhanced both beta-carotene 15,15'-dioxygenase activity and CRBP (II) level in rat intestine. These results suggest that the dioxygenase and CRBP (II) are regulated by the same mechanism involving long-chain fatty acids and their metabolites.     

Some effects of computerized interviewing on job applicant responses.

We examined the effects of computerized interviewing on applicant responses within the context of a laboratory simulation in which subjects were interviewed for either a low- or high-status position (clerk or management trainee) under one of four interview conditions: computerized, paper-and-pencil, or face-to-face with a warm or a cold behaving interviewer. The results indicated that subjects in nonsocial (computer or paper-and-pencil) interview conditions both scored lower on the Marlowe-Crowne measure of socially desirable responding (SDR) and reported their grade point averages and scholastic aptitude scores more accurately (with less inflation) than those in the face-to-face interview conditions. However, the use of nonsocial screening interviews for the high-status position engendered significantly higher levels of applicant resentment about the interview, relative to the conditions in which the interview procedure was appropriate (or more than appropriate) for the position level. This unintended behavioral consequence suggests one of the bounds that may influence the effectiveness of computerized interviewing. Contrary to expectations, we did not find the interpersonal style of the interviewer to significantly affect applicant resentment or SDR. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditions for complete self-healing breakdown in glow discharge polymerized styrene films

Breakdown patterns of glow discharge polymerized styrene film sandwiched between the top and base electrodes and fabricated on a glass substrate have been observed with a microscope. The breakdown patterns can be classified into three types: a broad ring of partly vanishing top electrode metal occuring around the breakdown hole in the dielectric (type A); a large hole made through the three layers (one dielectric and two metal layers), the dielectric film and the top electrode being folded back together at the periphery of the hole and the base electrode being melted over the hole area (type B); successive breakdown around the periphery of previous breakdown spots (type P). These patterns are interpreted in terms of the action of an arc across an extremely short gap as well as joule heating. Type A is preferable for attaining complete self-healing and the conditions that most favour the occurrence of type A holes are (a) the application of a positive voltage to the top electrode and (b) the top electrode being thin compared with the base electrode.     

Properties of electrical insulating materials at cryogenictemperatures: A literature review

Many insulating materials and systems for superconducting electrical equipment have been developed in response to the severe demands of safe usage, such as in cryogenic temperature, high mechanical stresses, high radiation, etc. They have been designed to fulfill very extreme service conditions, either at liquid helium or liquid nitrogen temperatures. Whatever the future industrial development, there is already abundant knowledge about insulating materials at cryogenic temperatures, and the feasibility has been proven. Many laboratories in the world continue research to increase this knowledge and to fill in the remaining gaps     

Effects of TA-0910, an orally active TRH analog, on the spinal reflex in spinal rats

Effects of TA-0910 (1-methyl-(S)-4,5-dihydroorotyl-L-histidyl-L-prolinamide), a new thyrotropin releasing hormone (TRH) analog, on spinal reflex potentials and flexor reflexes were compared with those of TRH in C1-spinal rats. Intravenously administered TA-0910 and TRH produced dose-dependent increases in the amplitudes of mono- and polysynaptic reflex potentials and withdrawal flexor reflexes. TA-0910 was more potent and more long-lasting than TRH. The stimulating actions of TA-0910 and TRH on the monosynaptic reflex potential were not antagonized by pretreatment with atropine, cyproheptadine, haloperidol or prazosin, suggesting no involvement of the cholinergic, serotonergic, dopaminergic or noradrenergic system. Intraduodenally administered TA-0910 also produced a lasting potentiation of the withdrawal flexor reflex, but intraduodenally administered TRH showed no effect. These results suggest that TA-0910 may be a more useful drug than TRH for spinal functional disorders.     

Pathogenic role of glutamate in hyperthermia-induced seizures

Hyperthermia induces seizures in both humans and rodents, but the underlying mechanism remains unknown. The present study showed that hyperthermia, causing rapid increase in body temperature, increases the concentration of glutamate (Glu) released into a cortical perfusate before onset of seizures in rats and that this increase in Glu concentration correlated with a decrease in seizure threshold temperature. These results indicate that increased cortical extracellular Glu induced by hyperthermia contributes to onset of seizures. The same mechanism may be involved in clinical seizures induced by fever in patients with febrile convulsions or epilepsy.     

High-field dielectric properties of polyethylene in the high-temperature region

Nonpolar polymers such as polyethylene or polypropylene are widely used as insulation materials, often under conditions involving strong electric fields and high temperatures. Under these conditions, the conduction loss due to DC-like carrier transport may give rise to a high-field AC dissipation factor (tan δ). This paper describes the high-field dielectric properties of polyethylene films at frequencies from 50 to 400 Hz and temperatures from room temperature to 100°C, as measured with a new type electrode design developed by the authors. In the high-temperature region, the AC dissipation current waveform at 50 Hz was also measured. At room temperature, the electric-field dependence of tan δ is almost unaffected by the frequency of the applied field. But at high temperatures and strong electric fields, tan δ tends to have a large field dependence and to be almost inversely proportional to the frequency. Thus the AC conductivity becomes independent of the frequency of the applied field in the region of strong fields and high temperatures. A theoretical analysis shows that the high-field dielectric loss is governed by two processes, namely, the dielectric relaxation loss inherent to the AC field and the DC-like carrier transport loss that becomes prominent in the high-temperature region, where AC dissipation current waveform becomes significantly nonsinusoidal.