Increased expression of 3-hydroxyanthranilate 3,4-dioxygenase gene in brain of epilepsy-prone El mice

The El mouse is an established animal model for human epilepsy. We previously reported that the level of quinolinic acid (QUIN), an excitotoxin, was high in the brain of epilepsy-prone El mice and that the increased production of QUIN was secondary to an increased activity of 3-hydroxyanthranilate 3,4-dioxygenase (3-HAO, EC 1.13.11. 6) in the brains of these mice. In this study, we cloned and sequenced the cDNA for 3-HAO and showed that its expression in the brain of El mice was higher than that of control ddY mice. These results suggest that a genetic defect leading to derepression of the 3-HAO gene expression in the brain may be involved in the pathogenesis for the epileptic diseases of El mice.     

Neuroblastoma growth factors derived from neurofibroma (NF1): participation of uridine in a neuroblastoma growth

Human glioma cell extracts were found to elicit a marked growth-promoting activity on human neuroblastoma cells. This activity was also detected in the extracts of neurofibroma type 1 (NF1; von Recklinghausen neurofibromatosis) comprising aberrant Schwann cell growth. The purified substance from the NF1 extracts by HPLC on ODS columns was identical to a pyrimidine nucleoside, uridine, the chemical structure of which was identified by gas chromatography-mass spectrometry. The authentic uridine showed a strong growth-promoting activity on human neuroblastoma cells. Other purine or pyrimidine nucleotides, their derivatives, and ribose sources for their syntheses were employed to test the activity; a purine nucleoside, adenosine, showed a stronger activity than uridine. The current study raises the possibility that human neuroblastoma cells may be affected by dysfunctions of the de novo pathway of both purine and pyrimidine nucleotide biosyntheses.     

Dispersion of fillers and the electrical conductivity of polymer blends filled with carbon black

Dispersion state of carbon black(CB) was studied in polymer blends which are incompatible with each other. It was found that CB distributes unevenly in each component of the polymer blend. There are two types of distribution. (1) One is almost predominantly distributed in one phase of the blend matrix, and in this phase fillers are relatively homogeneously distributed in the same manner as a single polymer composite. (2) In the second, the filler distribution concentrates at interface of two polymers. As long as the viscosities of two polymers are comparable, interfacial energy is the main factor determining uneven distribution of fillers in polymer blend matrices. This heterogeneous dispersion of conductive fillers has much effect on the electrical conductivity of CB filled polymer blends. The electrical conductivity of CB filled polymer blends is determined by two factors. One is concentration of CB in the filler rich phase and the other is phase continuity of this phase. These double percolations affect conductivity of conductive particle filled polymer blends.     

Central effect of melatonin against stress-induced gastric ulcers in rats

We investigated the role of melatonin in the induction of gastric lesions induced by water immersion restraint stress or centrally administered thyrotropin-releasing hormone (TRH). Melatonin (0.1-1 ng) injected intracisternally (i.c) 30 min prior to stress dose-dependently inhibited the induction of gastric lesions by water immersion restraint stress, while 100 micrograms/kg, i.p. failed to protect the gastric mucosa. Preadministration of melatonin (1 ng, i.c.) significantly reduced (83%) the severity of gastric lesions induced by a TRH analogue (500 ng, i.c.). Serum melatonin concentrations 30 min after administration of 1 ng melatonin i.c. did not differ from those of rats receiving i.c. vehicle. These results suggest that melatonin plays a protective, anti-stress, role in the gastric mucosa via a mechanism involving the central nervous system.     

Chemical modification of amino acid residues in glycerinated Vorticella stalk and Ca(2+)-induced contractility

The effects of sodium dichloroisocyanurate (NaDCC) and Solprogel (Laboratorios Inibsa, S.A., Barcelona, Spain), a compound that contains NaDCC plus a biodegradable polymer of acrylic acid, on the activity of DNA polymerase (DNA-P) associated with hepatitis B virus in serum were evaluated. DNA-P positive and negative pools of human serum samples were used as positive and negative stock virus. Inhibition of DNA-P activity by NaDCC and the commercial product was found to be concentration-dependent. Two minutes exposure to the minimum effective concentration of NaDCC (1000 ppm available chlorine) or Solprogel 16% (960 ppm available chlorine) totally inhibited DNA-P activity.     

ABSORPTION OF CARBON DIOXIDE INTO AQUEOUS DIETHANOLAMINE SOLUTIONS

The rates of absorption of pure carbon dioxide into aqueous diethanolamine solutions were measured at 25^°C in a liquid-jet column and a wetted-wall column. Experimental results were analyzed with the chemical absorption theory based on the penetration model. Physical solubility of carbon dioxide in aqueous diethanolamine solutions was determined from the absorption rates measured in a near pseudo first-order reaction regime and was found to show a salting-out effect. The measured absorption rates were in good agreement with the theoretical predictions for gas absorption with an irreversible third-order reaction.     

世界技术纺织品市场状况

“技术纺织品”包含与终端市场有关的多个系列加工活动。这个行业的产品既包括揩布等日常用品，也包括心脏瓣膜、航天复合材料和建筑用织物等特殊产品。衔接纤维生产商与用户市场的供应链是一个很长、很复杂的供应链，它包含了从纤维生产商到纱线和织物生产商以及染整厂、加工厂和制造商等大、小企业。这些企业都将技术纺织品纳入他们的产品范围或将它们作为所经营业务的一个基本部分。所有技术纺织品应用、生产活动和企业的共性是利用纤维（通常是加工成纤维、纱线和织物的形式）提供特定的技术性能，来满足最终用户或市场的需求．无论是作为最终产品，还是作为其它产品的组成部分。