Effects of conjugated linoleic acid isomers on the hepatic microsomal desaturation activities in vitro

The influence of individual conjugated linoleic acid (CLA) isomers on the Δ6 desaturation of linoleic and α-linolenic acids and on the Δ9 desaturation of stearic acid was investigated in vitro, using rat liver microsomes. The Δ6 desaturation of 18∶2n−6 was decreased from 23 to 38% when the ratio of 9cis,11trans-18∶2 to 18∶2n−6 increased from 0.5 to 2. The compound 10trans,12cis-18∶2 exhibited a similar effect only at the highest concentration. The Δ6 desaturation of α-linolenic acid was slightly affected by the presence of CLA isomers. The sole isomer to induce an inhibitory effect on the Δ9 desaturation of stearic acid was 10trans,12cis-18∶2.     

Forced intercalation probes (FIT Probes): thiazole orange as a fluorescent base in peptide nucleic acids for homogeneous single-nucleotide-polymorphism detection

Fluorescent base analogues in DNA are versatile probes of nucleic acid-nucleic acid and nucleic acid-protein interactions. New peptide nucleic acid (PNA) based probes are described in which the intercalator dye thiazole orange (TO) serves as a base surrogate. The investigation of six TO derivatives revealed that the linker length and the conjugation site decided whether a base surrogate conveys sequence-selective DNA binding and whether fluorescence is increased or decreased upon single-mismatched hybridization. One TO derivative conferred universal PNA-DNA base pairing while maintaining duplex stability and hybridization selectivity. TO fluorescence increased up to 26-fold upon hybridization. In contrast to most other probes, in which fluorescence is invariant once hybridization had occurred, the emission of TO-containing PNA probes is attenuated when forced to intercalate next to a mismatched base pair. The specificity of DNA detection is therefore not limited by the selectivity of probe-target binding and a DNA target can be distinguished from its single-base mutant under nonstringent hybridization conditions. This property should be of advantage for real-time quantitative PCR and nucleic acid detection within living cells.     

(<Emphasis Type="Italic">Z,Z</Emphasis>)-6,9-Heneicosadien-11-One: Major Sex Pheromone Component Of Painted Apple Moth, <Emphasis Type="Italic">Teia anartoides</Emphasis>

(Z, Z)-6,9-Heneicosadien-11-one (Z6Z9-11-one-21Hy) was identified as the major sex pheromone component of the painted apple moth (PAM), Teia anartoides (Lepidoptera: Lymantriidae), on the basis of (1) comparative gas chromatographic-electroantennographic detection (GC-EAD) analyses, GC-mass spectrometry (MS), high-performance liquid chromatography (HPLC)-MS, and HPLC-UV/visible spectroscopy of pheromone gland extracts and authentic standards; (2) GC-EAD analyses of effluvia of calling females; and (3) wind tunnel and field trapping experiments with a synthetic standard. In field experiments in Australia, synthetic Z6Z9-11-one-21Hy as a single component attracted male moths. Wind tunnel experiments suggested that a 4-component blend consisting of Z6Z9-11-one-21Hy, (6Z,9R,10S)-cis-9,10-epoxy-heneicosene (Z6-9R10S-epo-21Hy), (E, E)-7,9-heneicosadien-6,11-dione (E7E9-6,11-dione-21Hy), and 6-hydroxy-(E, E)-7,9-heneicosadien-11-one (E7E9-6-ol-11-one-21Hy) (all present in pheromone gland extracts) might induce more males to orient toward, approach, and contact the source than did Z6Z9-11-one-21Hy as a single component. Additional experiments are needed to determine conclusively whether or not Z6-9R10S-epo-21Hy, E7E9-6,11-dione-21Hy, and E7E9-6-ol-11-one-21Hy might be minor sex pheromone components of PAM. Moreover, attractiveness of synthetic pheromone and virgin PAM females needs to be compared to determine whether synthetic pheromone could replace PAM females as trap baits in the program to monitor eradication of exotic PAM in New Zealand.     

Are hormones from the neuropeptide Y family recognized by their receptors from the membrane-bound state?

Hormones and many other neurotransmitters, growth factors, odorant molecules, and light all present stimuli for a class of membrane-anchored receptors called G protein-coupled receptors (GPCRs). The GPCRs are the largest family of cell-surface receptors involved in signal transduction. About 1% of all known genes of Drosophila and more than 5% of the genes of Caenorhabditis elegans encode GPCRs. In addition, more than 50% of current therapeutic agents on the market target these receptors. When the enormous biological and pharmaceutical importance of these receptors is considered, it is surprising how little is known about the mechanism with which these receptors recognize their natural ligands. In this review we present a structural approach, utilizing techniques of high-resolution NMR spectroscopy, to address the question of whether peptides from the neuropeptide Y family of neurohormones are recognized directly from solution or from the membrane-bound state. In our studies we discovered that the structures of the membrane-bound species are better correlated to the pharmacological properties of these peptides than the solution structures are. These findings are supported by the observation that many biophysical properties of these peptides seem to be optimized for membrane binding. We finally present a scenario of possible events during receptor recognition.     

高浓度二氧化硫以工业用氧在沸腾层转化器氧化

使用工业用氧焙烧铜精矿和黄铁矿精矿可得到高浓度二氧化硫(50%—90%SO_2)的炉气。在接触法硫酸生产中用氧来氧化,过程可增强3—7倍,并直接制得100%SO_3和65%发烟硫酸。在固定层转化器进行此过程,对于从触媒层排出热和在过剩氧很小时氧化二氧化硫,都有一定的困难。而且设备体积大,管理和操作复杂。至于循环法仅适于处理洁净的SO_2和O_2(不少于99%)。     

Cartesian echo planar hybrid scanning with two to eight echoes

A method of fast nuclear magnetic resonance (NMR) imaging which uses only square wave gradient shapes and also collects data on Cartesian coordinates in a way similar to the blipped echo planar imaging method (BEPI) is described. The method is a heuristic attempt at finding an optimal data collection strategy for NMR imaging. Its advantages and disadvantages compared to other methods are carefully analyzed. Clinical size anatomical (head and body) images are shown. It is found that the interecho phase-angle discrepancies that are caused bv the B(0) inhomogeneity and by the gradient wave form distortion can largely be eliminated by using the half Fourier method with full Fourier phase map correction, but one phase map is required for each echo. GRASS/FLASH spoiling techniques are incorporated into the method in order to allow multiecho speed increases for scans which would run under 10 s using a single-echo method. The technique can be applied directly to GRASS/FLASH itself, as is demonstrated by a two-echo GRASS scan. The fastest image was 1.9 s.     

D2工具钢在气淬和回火过程中的各向异性畸变

分别使用铸造试样及两种不同锻造程度的锻件试样，对高合金冷作模具钢D2在气淬和回火过程中的畸变行为进行了研究。试验结果表明，铸造试样的畸变是等向性的，而锻造试样的畸变显然呈各向异性。各向异性畸变程度随奥氏体化温度的升高而增加。在本试验范围内，不同的锻造程度对各向异性的畸变程度影响不大。回火后各向异性畸变程度有所降低。使用测膨胀方法及金相检验探讨了产生各向异性畸变的可能机制。     

新型边部加料预焙阳极电解槽

近年来,为减轻铝电解生产的劳动强度,主要采用在槽上设置打壳设备和氧化铝加料斗,并由电子计算机控制的自动加料型式的预焙阳极电解槽。     

使用不同时间的发电厂中压阀门螺栓的组织和力学性能研究

发电厂中压阀门螺栓材料为Inconel 783镍基高温合金,在高温、高压下使用。研究了使用1.5年和4.5年的螺栓的显微组织和力学性能。结果表明:与使用了1.5年的螺栓相比,使用了4.5年的螺栓晶粒较粗大,析出的β-AlNi相更多,强度升高,塑性、韧性下降,显微硬度降低,但宏观硬度变化不明显。     

纵向旋转切削加工对环形零件畸变的影响

通过旋转试验和有限元分析介绍了工件在切削加工过程中产生的畸变情况，分析了工件的装夹方式、切削速度、切削深度和进刀量对100Cr6钢环圆度的影响。通过去应力退火释放冷加工诱发的残余应力后工件的圆度与切削参数有关。另外测试了被试验环的表面残余应力，其表面残余应力与装夹方式有关。将测量的装夹力作为计算参数输入，通过有限元分析方法测试了装夹方式对工件变形的影响。协同测量结果示出了装夹方式影响工件变形的一个主要因素，表面残余应力与工件的径向变形有关，最大的拉伸应力位于夹口位置。旋转切削试验结果表明，提高切削速度圆度会稍有增加；随着切削深度的加大，圆度呈下降趋势，尽管切削力增加了；进给量的增加会导致更高的切削力，因此圆度值也增加；常规的去应力退火可使被加工环的圆度值增加。