The influence of the alloying elements upon the transformation kinetics and morphologies of ferrite plates in alloy steels

A series of Fe-C-X and Fe-C-X₁-X₂ alloys in which X, X₁ and X₂ either raise or depress the activity of C iny were investigated by autodilatometer, optical microscopy, and transmission electron microscopy (TEM) to reveal the relations among the chemical composition, transformation kinetics, and morphology of ferrite plates. The incubation time of austenite decomposition at the nose temperature in the time-temperature-transformation (TTT) diagrams, the concentration of C in y in contact with theα/gg boundary, and the growth rate of ferrite were evaluated to estimate the magnitude of the solute drag-like effect (SDLE) for the different alloying elements used. All the results are consistent qualitatively with the SDLE hypothesis. This article is based on a presentation made at the Pacific Rim Conference on the “Roles of Shear and Diffusion in the Formation of Plate-Shaped Transformation Products,” held December 18-22, 1992, in Kona, Hawaii, under the auspices of ASM INTERNATIONAL’S Phase Transformations Committee.     

Mode of the autocrine/paracrine mechanism of growth hormone action

GH is synthesized at multiple extrapituitary sites suggestive of an autocrine/paracrine mechanism of action. We have investigated a possible autocrine/paracrine mechanism of GH action, compared the cellular response to exogenous versus endogenously produced GH, and determined the nature of the interaction between external stimuli and endogenously produced GH. BRL cells expressing the GH receptor were transiently transfected with expression plasmids containing either the hGH or the bGH gene and the response of the cell was measured by CAT reporter plasmids requiring either STATs 1 and 3 or STAT5 for their response. Transient transfection of the hGH gene resulted in hGH accumulation in the cell and secretion into the media. The functional response through STATs 1 and 3 and STAT5 obtained with endogenously produced hGH was comparable or greater in magnitude to that obtained with the maximal stimulatory dose of exogenous hGH. Similar results were obtained with an expression plasmid containing the bGH gene. Endogenously produced hGH interacted in an additive manner when combined with submaximal doses of both exogenous hGH and serum. Such results were also observed in a more physiologically relevant mammary carcinoma cell line (MCF-7). The nonreceptor-dimerizing hGH antagonist, hGH-G120R, used in cells expressing the homologous receptor extracellular domain was able to only partially inhibit the response of the cell to endogenously produced hGH, in contrast to full inhibition of exogenous hGH. We therefore conclude that GH can function in an autocrine/paracrine manner, additive in effect to external stimuli.     

Mobility modeling, location tracking, and trajectory prediction inwireless ATM networks

Wireless ATM networks require efficient mobility management to cope with frequent mobile handoff and rerouting of connections. Although much attention has been given in the literature to network architecture design to support wide-area mobility in public ATM networks, little has been done to the important issue of user mobility estimation and prediction to improve the connection reliability and bandwidth efficiency of the underlying system architecture. This paper treats the problem by developing a hierarchical user mobility model that closely represents the movement behavior of a mobile user, and that, when used with appropriate pattern matching and Kalman filtering techniques, yields an accurate location prediction algorithm, HLP, or hierarchical location prediction, which provides necessary information for advance resource reservation and advance optimal route establishment in wireless ATM networks     

火炸药包装用纸桶的研究

简述了我国火炸药包装的现状。介绍了火炸药用纸桶包装的研究情况，其中，较详细叙述了纸桶的力学性能、运输和使用试验结果，分析了纸桶包装火炸药的社会、经济效益。     

A study on the anodic protection of Titanium evaporators in Al2(SO4)3 solution

The feasibility of the anodic protection of titanium evaporators in Al₂(SO₄)₃ solution was studied by the measurement of polarization curves, weight loss, solubility of passive film and AC impedance. The protection parameters and efficiency were determined. In addition, the practical technology of anodic protection was studied by screening reference electrodes and auxiliary cathodes. Throwing power was also measured. Four rows of tube-type evaporators of titanium have been anodically protected in situ. Field tests lasting more than one year show satisfactory results.     

Effect of pentobarbital on normal brain protection and on the response of 9L rat brain tumor to radiation therapy

The authors attempted to confirm published reports that pentobarbital protects against radiation-induced damage to normal rat brain, as well as enhances radiotherapeutic efficacy in a rat brain tumor model. They evaluated animal survival in 9L gliosarcoma-burdened rats that received whole-brain radiation therapy (16, 24, 32, or 40 Gy) while under intraperitoneal pentobarbital (60 mg/kg) or intramuscular ketamine (60 mg/kg) sedation. The animals were examined at autopsy to attribute death to either intracranial tumor growth or normal brain toxicity in the absence of discernible tumor. There was no difference between the two anesthesia groups regarding the survival of unirradiated animals. Radiation therapy produced a significant dose-dependent prolongation in animal survival, which was limited by the development of normal tissue toxicity at the higher doses. When compared to ketamine anesthesia, pentobarbital anesthesia appeared to offer some protection (not statistically significant) against early (but not late) toxicity at selected radiation doses. A reduction in the number of deaths from tissue toxicity suggested an increased antitumor effect, but again this was not statistically significant. Only in one case was there even a marginal significant difference (p = 0.045) between overall therapeutic efficacy in rats sedated with pentobarbital versus ketamine. While there may be a radioprotective effect of pentobarbital in rat brains without intracranial tumor, there is no conclusive evidence for either radioprotection or significant improvement of radiotherapeutic efficacy in this 9L rat brain tumor model.     

含淀粉聚乙烯膜的时控光降解研究

使用复合光降解剂，得到了可光降解的生物降解膜。对膜的光降解进行了考察，并对影响光降解的因素进行了讨论，结果表明，我们所制得的膜是一种较好的时控光降解膜。     

A novel DNA duplex. A parallel-stranded DNA helix with Hoogsteen base pairing

We show here for the first time that a stable parallel double helix with Hoogsteen pairing can exist independently of the triple helix of which it is a component part. The experiments employ DNA oligonucleotides with mixed sequences of normal bases. These duplexes are distinct from previously reported ribopolynucleotide helices containing bulky substituents which prevent Watson-Crick pairing as well as from parallel duplexes with Donohue, or reversed Watson-Crick, pairing. Stoichiometry is established by mixing curves and gel electrophoresis. Tm depends linearly upon pH, increasing with acidity because of the need to protonate N3 of C. The Tm of the 20-mer studied here is 52 degrees C at pH 5.2 and 0.1 M NaCl. At pH above 6, the molecule rearranges to form an antiparallel duplex with imperfect Watson-Crick pairing and loops, and the Tm is then independent of pH. The CD spectrum of the parallel duplex is very similar to that of the corresponding triple helix but quite different from that of the Watson-Crick helix. The infrared spectrum in the double bond region closely resembles that of the triple helix but, as with the CD, is quite different from that of the Watson-Crick duplex. The infrared spectra of the duplex and triple helix are also nearly identical in the region form 800 to 1000 cm-1, which is sensitive to backbone conformation. The only symmetry element present is a pseudorotational axis coincident with the helix axis of the parallel duplex as well as with the axis of the corresponding triple helix.(ABSTRACT TRUNCATED AT 250 WORDS)