模具钢的局部合金化

对热作和冷作模具钢(AISIH13和D3)的表面进行了局部合金化处理的试验。在试样表面用等离子喷镀钼钢、钒钢及硼钢粉末。由电子束按照不同的参数熔化喷镀层及基体。测定了局部熔化层中的合金元素的分布、显微组织、相及硬度。也测量了局部合金化层的回火抗力。采用不同的熔化参数, 熔化层中合金元素的含量也不同。合金化层的特点在于硬度和回火抗力。建立了电子束局部合金化层的合金元素含量、显微组织、相及机械性能之间的关系。     

ATOMISTIC SIMULATIONS FOR Ni/Al INTERMETALLICS

ＡＴＯＭＩＳＴＩＣＳＩＭＵＬＡＴＩＯＮＳＦＯＲＮｉ／ＡｌＩＮＴＥＲＭＥＴＡＬＬＩＣＳＢＡＳＫＥＳＭ．Ｉ．（ＳａｎｄｉａＮａｔｉｏｎａｌＬａｂｏｒａｔｏｒｉｅｓ，Ｌｉｖｅｒｍｏｒｅ，Ｃａｌｉｆｏｒｍｉａ）Ａｂｓｔｒａｃｔ：ＡｌａｒｇｅｎｕｍｂｅｒｏｆＥ...     

Behaviour of the Antitumor Agent Vanadocene Dichloride in Physiological and Therapeutic Media, Blood Plasma and Human Blood - An EPR Study

By means of EPR spectroscopy the behaviour of the vanadocene dichloride (I), Cp(2)VCl(2) (Cp=eta(5)-C(5)H(5)), in various deoxygenated and non-deoxygenated physiological media and therapeutic solution as well as in blood plasma and stabilized human blood was studied. On the basis of measured values of isotropic spectroscopic splitting factor g(iso) and isotropic hyperfine coupling constant A(iso), the vanadocene species, [Cp(2)V(H(2)O)Cl](+) (II; g(iso)= 1.985, |A(iso)| = 7.68 mT), [Cp(2)V(H(2)O)(2)](2+) (III; g(iso)= 1.983, |A(iso)| = 7.92 mT), [Cp(2)V(OH(2) (IV; g(iso)= 1.991, |A(iso)| = 6.285 mT), [Cp(2)VCl(DMSO)](+) (V; g(iso)= 1.985, |A(iso)| = 7.69 mT), the vanadyl species [VO(DMSO)(5)](2+) (VI; g(iso)= 1.964, |A(iso)| = 10.78mT) and [VO(H(2)O)(5)](2+) (VII; g(iso)= 1.955, |A(iso)| = 11.56 mT) have been identified. From the measurements it follows that I does not react in its first coordination sphere with any component of a system used other than water and DMSO, resp. As to water-containing media, its behaviour is fully consistent with that of I in pure aqueous media. It was found the only vanadocene species present after application of the therapeutic solution of I into human blood to be IV not interacting in its first coordination sphere with any blood component.     

Identification of the pathway of α-oxidation of cerebronic acid in peroxisomes

Cerebronic acid (2-hydroxytetracosanoic acid), an α-hydroxy very long-chain fatty acid (VLCFA) and a component of cerebrosides and sulfatides, is unique to nervous tissues. Studies were carried out to identify the pathway and the subcellular site involved in the oxidation of cerebronic acid. The results from these studies revealed that cerebronic acid was catabolized by α-oxidation to CO₂ and tricosanoic acid (23:0). Studies with subcellular fractions indicated that cerebronic acid was α-oxidized in fractions having particulate bound catalase and enzyme systems for the β-oxidation of VLCFA (e.g., lignoceric acid), suggesting peroxisomes as the subcellular organelle responsible for α-oxidation of cerebronic acid. Etomoxir, an inhibitor of mitochondrial fatty acid oxidation, had no effect on cerebronic acid α-oxidation. Further, cerebronic acid oxidation was found to be dependent on the presence of NAD⁺ but not FAD, NADPH, ATP, Mg²⁺, or CoASH. Intraorganellar localization studies indicated that the enzyme system for the α-oxidation of cerebronic acid was associated with the peroxisomal limiting membranes. Studies on cultured fibroblasts from normal subjects and patients with peroxisomal disorders indicated an impairment of α-oxidation of cerebronic acid in cell lines that lack peroxisomes [e.g., Zellweger syndrome (ZS)]. On the other hand, α-oxidation of cerebronic acid was found to be normal in cell lines from X-linked adrenoleukodystrophy, adult Refsum disease, and rhizomelic chondrodysplasia punctata. Our results clearly demonstrate that α-oxidation of α-hydroxy VLCFA (cerebronic acid) is a peroxisomal function and that this oxidation is impaired in ZS. Furthermore, this α-oxidation enzyme system is distinct from the one for the α-oxidation of β-carbon branched-chain fatty acids (e.g., phytanic acid).     

Effect of medium-chain fatty acid positional distribution in dietary triacylglycerol on lymphatic lipid transport and chylomicron composition in rats

The present study was carried out to examine if the positional distribution of medium-chain fatty acid (MCF) in dietary synthetic fat influences lymphatic transport of dietary fat and the chemical composition of chylomicrons in rats with permanent cannulation of thoracic duct. Four types of synthetic triacylglycerol were prepared: (i) sn-1(3) MCF-sn 2 linoleic acid, (ii) interesterified sn-1(3) MCF-sn 2 linoleic acid, (iii) sn-2 MCF-sn-1(3) linoleic acid, and (iv) interesterified sn-2 MCF-sn-1(3) linoleic acid. A purified diet composed of equal amounts of the synthetic fat and cocoa butter was given to rats with permanent lymph duct cannulation. The positional distribution of MCF in the dietary fat had no significant effect on the lymph flow, triacylglycerol output, phospholipid output, lipid composition of chylomicrons, or the particle size. The positional distribution of MCF in the synthetic triacylglycerol was maintained in the chylomicron triacylglycerol. These results showed that MCF in the dietary triacylglycerol is transported into lymphatics and the positional distribution is well preserved in chylomicron triacylglycerol.     

Functional properties of a protein product from Caryodendron orinocense (Barinas nut)

The functional properties of Caryodendron orinocense protein product were investigated and compared with those of soybean (Glycina maxima). The product protein content was 24.47 g/100 g (Nx6.25). Solubility increased at both sides of the isoelectric point (pH 4.0) and with increased NaCl concentration up to 0.5M. Compared with soybean flour (50% protein), the protein product exhibited higher water and oil absorption, but lower emulsifying activity, emulsion stability, foaming capacity, and foam stability, the last one increase at higher pH. Emulsifying activity, foaming capacity, and foam stability were ionic strength dependent. C. orinocense protein product increased its emulsifying activity steadily from 0.05M to 0.75M NaCl, while it remained almost constant for soybean flour. Foaming capacity increased drastically at pH 10. The minimum time and concentration to form a gel was 20% in 4 min and 10% in 8 min for the Caryodendron protein product and soybean flour, respectively. The bulk density was 0.5056+/-0.0041 g/mL.     

Role of semiochemicals in mate location by parasitic sea louse,Lepeophtheirus salmonis

The role of olfaction and diffusible pheromones in mate location behavior of sea lice, Lepeophtheirus salmonis, was assessed with Y-tube behavioral bioassays. The pheromone emitting animals were located in a chamber in one arm of a Y-tube arena, with artificial seawater flowing through both arms. Adult male sea lice displayed both activation and directional responses to seawater conditioned with preadult II virgin females, but were only activated by mated adult female conditioned water. Further, when males were given the choice of preadult II virgin females or mated adult females, a significant number of males chose the arm with the preadult II virgin females. Adult males showed activation responses when presented with water conditioned with adult males but were not attracted to them. When presented with adult males, preadult II virgin females showed only directional responses, but not activation responses. Preadult II virgin female conditioned water was extracted using solid-phase extraction (SPE) protocols pioneered for semiochemical isolation. Adult male sea lice showed significant directional responses to the preadult II virgin female SPE extract. Distillation under vacuum was performed on the extract to give a distillate comprising components with a molecular weight range and physical properties comparable to those of compounds utilized as volatile semiochemicals by terrestrial organisms and a residue comprising components with higher molecular weight range comparable to those utilized as involatile semiochemicals. Adult males were found to be both significantly activated and attracted to the distillate, but not to the residue. This research provides evidence that small, lipophilic organic molecules are used by sea lice as sex pheromone signals to locate a member of the opposite sex.     

快速加氢热介技术应用于从煤生产苯、乙烯、合成天然气的工艺设想

煤的快速加氢热介(FHP)是一种能在单段、高产量反应器中直接生产甲烷、乙烷和三苯(BTX,即苯、甲苯和二甲苯)的新技术。快速加氢热介技术是将煤在稀释状态输送至反应器中,快速加热,短暂停留(1—2秒钟)。当结合为综合的基础转化联合企业时,快速加氢热介技术能用来生产合成天然气(SNG)、乙烯、丙烯、苯和F—T合成的醇类等一系列产品。本文根据用褐煤在快速加氢热介反应器中的操作经验,概述了一个概念化工厂的工艺技术和经济情况。这个工厂假设座落在美国得克萨斯州广阔的褐煤田附近。采用通融资金计算法估算合成天然气的成本,并以石油化产市场价格销售联产的化工产品,按照煤炭价格、利率、债务/资产比、联产化学品价格等因素,计算出的合成天然气20年内的平均成本在? 3～4/百万BTU范围内变动。     

具有抗菌活性的胍类化合物

三十年代中期当一系列胍类和缩二胍类化合物被报道具有杀细菌剂和消毒剂性质时,人们就已经认识取代基胍类化合物的生物活性。继而对许多胍类衍生物进行了研究,用作植物保护剂。其中有一些,如多果定(dodine)、双辛胍胺(guazatine)得到商业性开发,成为有相当重要性的农用杀菌剂。本文主要评述这类被证实有效或可能有效的活性胍类化合物。     

Biased distribution of the branched-chain fatty acids in ceramides of vernix caseosa

The compositions of ester- and amide-linked fatty acids from ceramides of human vernix caseosa were described with emphasis on the distribution of the branched-chain fatty acid (BCFA). Two novel ceramides were isolated from vernix caseosa in the course of this study: the acylated type of esterified α-OH-hydroxyacid/sphingosine ceramide (Cer[EAS]) and nonacylated type of non-OH fatty acid/hydroxysphingosine ceramide (Cer[NH]). Their chemical structures were identified by nuclear magnetic resonance and chemical procedure. The Cer[EAS] was an acylceramide and consisted of the highest concentrations of ester- and amide-linked BCFA (62 and 67%, respectively). The iso- or anteiso-branching structures of the aliphatic chains were confirmed by the mass spectra of their picolinyl or pyrrolidide derivatives. As a whole, amide-linked fatty acids of ceramides 1–7 and Cer[NH] were normal types of straight-chain fatty acids with or without α- or ω-hydroxylation. The BCFA concentrations of amide-linked fatty acids in these ceramides (ceramides 1–7 and Cer[NH]) were low and less than 10%. The BCFA thus occurred exclusively in a novel acylceramide of Cer[EAS] in the vernix caseosa.