Utility of molecular epidemiology of tuberculosis

In Bacillus sp. YUF-4, acetylacetoin synthase was induced by acetoin, while glucose inhibited the induction. The enzyme was purified 111-fold by 6 purification steps, and a further purification followed, by HPLC using a TSK gel, Phenyl-5PW RP. The resulting enzyme gave a single band with a molecular mass of 62 kDa by SDS-PAGE and 220 kDa by gel filtration. Some enzymic characteristics were studied.     

Extraction, purification and evaluation of structures and physico-chemical properties of glycosaminoglycans

Heparin was extracted and purified from beef intestinal mucosa. The two components, fast moving heparin and slow moving heparin were purified by selective precipitation as barium salts. Heparan sulfate was extracted and purified from beef spleen. Dermatan sulfate was purified from beef intestinal mucosa and chondroitin sulfate from bovine trachea. The purity of the purified glycosaminoglycans was evaluated by agarose-gel and cellulose polyacetate electrophoresis and by specific optical rotation. The relative molecular masses of glycosaminoglycans were estimated by high performance-size exclusion chromatography and the sulfate to carboxyl ratio by titrimetric analysis. The disaccharide pattern of heparin, fast moving and slow moving heparins and heparan sulfate were determined by specific enzymatic cleavage using heparinase I, II and III; the disaccharide composition of dermatan sulfate and chondroitin sulfate was evaluated by cleavage by chondroitinase ABC. The disaccharides obtained by enzymatic cleavage were qualitatively and quantitatively analysed by strong anion exchange-high performance liquid chromatography. The sulfate to carboxyl ratios of glycosaminoglycans were also determined by this technique and compared with the values obtained by titrimetric analysis.     

不锈冷轧带钢表面光洁度的控制

在生产中，不锈冷轧带钢的表面光洁度一般用粗糙度进行控制，其粗糙度越低，光洁度越高。应使用低粗糙度和低微小缺陷面积率的不锈热轧带钢，高的总压下量，低粘度轧制油和平整率达到1％的工艺轧制可获得较高光洁度的不锈冷轧带钢。高速钢轧辊轧制的不锈冷轧带钢的光洁度优于模具钢轧辊。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Method of differential prognostication of pertussis morbidity

The authors present a method of differential prognostication of pertussis morbidity permitting to consider in prognostication the tendencies of individual subsets of the dynamic series which could be conditioned by individual causes. The general picture of the phenomenon to be prognosticated is obtained by superimposition of the values prognosticated by each of the segregated subsets.     

Investigation of endogenous neurotransmitters of guinea pig gallbladder using nicotinic agonist stimulation

Gallbladder motility is modulated by intrinsic nerves, the identities of which are not well established. The aim of this study was to determine the effect of nicotinic receptor stimulation of intrinsic nerves on gallbladder muscle contractility. Guinea pig gallbladder muscle strips were studied in vitro. Histamine 1 microM was used to increase baseline tone. The nicotinic receptor agonist, 1,1-dimethyl-4-phenylpiperazinium (DMPP), produced a biphasic response characterized by an initial transient contraction followed by a sustained relaxation. The initial contraction was inhibited by the neural blocker tetrodotoxin, the nicotinic antagonist hexamethonium, and the muscarinic antagonist atropine, but not by a substance P receptor antagonist or a bombesin receptor antagonist. The relaxation response to DMPP was not affected by tetrodotoxin, but was reduced by hexamethonium and omega-conotoxin GVIA, an inhibitor of neurotransmitter release. The relaxation response was reduced by the nitric oxide synthase inhibitor L-NAME, but not by a vasoactive intestinal peptide antagonist or propranolol. DMPP produces a biphasic response in the guinea pig gallbladder. The initial contractile response is mediated by nicotinic receptors on the cell body or axon of cholinergic nerves. The relaxation response appears to result, in part, from activation of nicotinic receptors on nerve terminals of nitric oxide-releasing nerves. These results suggest nicotinic receptors have heterogeneity in location depending on excitatory or inhibitory neuronal function.     

共沉淀法制备超细LaCoO3中聚乙二醇的作用研究

通过zeta电位、红外光谱等研究了用共沉淀方法制备LaCoO3时分散剂-聚乙二醇PEG-4000）的作用机制;通过粘度测定选择其适宜的使用量. 结果表明： 聚乙二醇的防团聚性能是通过在超细粉体的前驱体上吸附, 进而主要通过空间位阻稳定机制发挥作用的. 当其使用量为前驱体质量的3.0%时, 可制备出团聚程度轻、分散性良好的超细LaCoO3粉体.     

Cholinergic modulation of the release of [3H]acetylcholine from synaptosomes of the myenteric plexus

The purpose of these experiments was to determine if cholinergic agents affected the release of acetylcholine (ACh) from a synaptosomal preparation of the guinea pig ileum myenteric plexus. The synaptosomal preparation was first incubated with the precursor [3H]choline; subsequently, release of the stored [3H]ACh was measured. The release was decreased by oxotremorine or exogenous ACh plus hexamethonium and increased by exogenous ACh plus evoked release that was inhibited by nicotinic antagonists or muscarinic agonists. Release was stimulated half-maximally by approximately 2 microM- and maximally by 10 microM-DMPP. Either in the absence of calcium or at 0 degrees C, DMPP was without effect. The effect of 10 microM-DMPP was brief, a significant stimulation occurring only within the first 2 min at 37 degrees C. Tetrodotoxin also inhibited excitation by DMPP but not completely. Thus, the release of [3H]ACh appears to be presynaptically modulated, negatively by muscarinic agonists and positively by nicotinic agonists.     

Determinants of the nature of environmentally induced hypoalgesia.

Factors that determine whether naltrexone and pentobarbital anesthesia block the hypoalgesia produced by electric shock were investigated. One shock was followed by an initial hypoalgesia that was reversed by naltrexone but was not affected by pentobarbital. When testing was conducted in the shock context, early hypoalgesia was followed by a hypoalgesia that was still reversed by naltrexone but was eliminated by pentobarbital anesthesia. This second hypoalgesia did not occur when testing was conducted after removing the animal from the shock apparatus. Five shocks were also followed by 2 separable responses. The first response was not reduced by pentobarbital, but it was not blocked by naltrexone. This initial response was not prevented by removal from the shock context, but the 2nd response did not occur after removal. The pattern after 80 shocks was quite different. Here the hypoalgesic response did not appear to change in character across the 10 min of testing or with removal from the shock apparatus. The response persisted for 10 min in the shock context or after removal and was blocked by both naltrexone and pentobarbital throughout its entire duration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of Zn Vaporization on Wetting of Al-galvanized Steel in Cold Metal Transfer Process

The wetting of galvanized steel by molten Al alloys was studied in the cold metal transfer process by the sessile drop method using a high speed video camera.The wetting behavior can be divided into two typical cases,trending of non-wetting by using small wire feeding speed and wetting by using large wire feeding speed.The Leidenfrost effect is caused by the volatilization of Zn,which is responsible for the former case.The enhanced wettability of steel by Al and the weakening of the Leidenfrost effect are responsible for the latter case.Zn is the destabilizing factor for Al-steel joining that needs to be avoided by a reasonable design of process.     

Psychobiology of Altered States of Consciousness.

The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rediscovering the science of the history of life

The effects induced by L-arginine (L-Arg) on the short-circuit current and potential difference of Pleurodema thaul skin were investigated. L-Arg, but not D-Arg significantly increased the short-circuit current and potential difference when applied to the serosal surface. The effects of L-Arg were antagonized by amiloride, NG-nitro-methyl-L-arginine (L-NAME) and by methylene blue. Carbachol and acetylcholine induced significant increases of both electrical parameters of the toad skin. These effects of the muscarinic cholinergic drugs were potentiated by a low concentration of L-Arg and antagonized by L-NAME or methylene blue. Carbachol and acetylcholine induced significant increases of both electrical parameters of the toad skin. These effects of the muscarinic cholinergic drugs were potentiated by a low concentration of L-Arg and antagonized by L-NAME or methylene blue. Addition of dibutyryl cyclic guanosyl monophosphate (db cGMP) or dibutyryl cyclic adenosine monophosphate (db cAMP) increased short-circuit current and potential difference. The effects of db cGMP, but not those of db cAMP were antagonized by L-NAME. The consecutive application of db cGMP and db cAMP induced additive effects. These results suggest that L-Arg increases transport in toad skin presumably acting through the formation of nitric oxide, which then stimulates cytoplasmic guanylate cyclase and leads to increased Na+ and K+ transport. The effects of L-Arg and carbachol were antagonized by acute application of morphine; however, a rebound response was observed when carbachol or noradrenaline were given after prolonged exposure of the skin to morphine, which suggests an adaptive response of the skin involving both cGMP and cAMP. Responses to both nucleotides were unchanged by morphine.     

Molecular geometry of inhibitors of the uptake of catecholamines and serotonin in synaptosomal preparations of rat brain

Several compounds of relatively rigid molecular structure have been found to exert strong blockade of monoamine uptake by synaptosomal preparations of rat corpus striatum (dopamine and serotonin) and hypothalamus (norepinephrine). These include CP-24,441 (1R, 4S-N-methyl-4-phenyl-1,2,3,4-tetrahydro-1-naphthylamine), EXP-561 (4-phenylbicyclo[2.2.2]octan-1-amine), nomifensine and nefopam. The well-defined molecular geometry of the potent inhibitor EXP-561 is a fundamental structural/conformational requirement for uptake blocking activity for the large family of phenylbutylamine- and phenoxypropylamine-related inhibitors. The tubular configuration of EXP-561 may be the most appropriate for blocking serotonin uptake. The requisite conformation for blocking dopamine uptake appears to be defined by the combination resulting from superimposition of the CP-24,441 and nomifensine structures. The conformation defined by the combination resulting from superimposition of the CP-24-441 and desipramine structures is apparently optimal for blocking norepinephrine uptake. The conformational requirements for diphenylpropylamine-related uptake blockers may be defined by the rigid compound CP-39,332 (N-methyl-4-phenyl-1,2,3,4-tetrahydro-2-naphthylamine). The actual potency of any given inhibitor is probably modulated by additional structural and stereochemical factors.     

混合菌诱变及浸出碲矿的研究

利用紫外线(UV)、亚硝基胍(NTG)及其组合为诱变剂,对从四川石棉矿区的水土样中富集的混合菌进行诱变,并用于浸出碲矿。结果表明,在UV照射5 min时(15 W、距离30 cm),混合菌活性提高51.6%;用1.0 g/L NTG处理50 min后,混合菌有较高的活性,提高了57.4%;经复合诱变后,混合菌的活性分别提高59.5%和63.3%。浸矿试验表明,诱变后混合菌浸矿25 d后,碲的浸出率最大可提高26.7%。     

Study of acid-base equilibria of fleroxacin

The acid-base equilibria of fleroxacin were studied by means of potentiometry and spectrophotometry. It was established that fleroxacin undergoes a complex acid-base equilibrium due to its zwitterionic nature and two proton-binding sites of similar acidity. The stoichiometric equilibrium constants were determined at 25 degrees C and constant ionic strength 0.1 M (NaCl). The acidity constants pK1 = 5.59 +/- 0.01 and pK2 = 8.08 +/- 0.04 were found by potentiometry, and pK1 = 5.61 +/- 0.03 and pK2 = 8.11 +/- 0.06 by spectrophotometry. The distribution diagram of the corresponding ionic species is given.     

管件用管性能优化与改进

分析宝钢管件用管的原有实物质量和国外同类钢管的性能,通过降低成分设计中碳含量和硅含量提高钢管的塑性和韧性,适当提高锰含量以确保强度,提升钢管机械性能对后续加工的适应性。同时,通过改进张力减径机导向管固定方式、张减孔型合理配置和输送装置跟踪修磨等合适的表面质量控制措施,避免钢管在轧制中产生辊印和外表擦伤。生产证明,材质和生产工艺的改进使管件用管的实物质量得到改善,满足用户要求。     

Formation of reactive oxygen species following bioactivation of gentamicin

The present study investigated the ability of gentamicin to catalyze free radical reactions and probed the underlying mechanisms by hydroethidine imaging, oxygen consumption, and reduction of cytochrome c. In Epstein-Barr virus-transformed lymphoblastoid cells, a respiratory burst was induced by phorbol ester and detected by hydroethidine, a fluorescent indicator of superoxide radical. The addition of gentamicin increased the fluorescence two-fold while gentamicin did not produce fluorescence in the absence of phorbol ester. In membrane preparations, gentamicin did not enhance NADPH consumption ruling out a direct activation of NADPH oxidase. The formation of reactive oxygen species by gentamicin was additionally supported by experiments that showed gentamicin increased oxygen consumption two-fold in intact cells and a cell-free system. In addition, generation of superoxide was indicated by the gentamicin-stimulated reduction of cytochrome c. The stimulation by gentamicin depended upon the presence of iron (FeII/FeIII) and of arachidonic acid as an electron donor. These results support the hypothesis that an iron-gentamicin complex can increase reactive oxygen species in nonenzymatic and in biological systems. The requirement for a reductive activation in intact cells (e.g., by a respiratory burst) is interpreted as the conversion of an inactive FeIII-gentamicin to a redox-active FeII-gentamicin complex.     

Nitrosation of dialkylamines in the presence of bile acid conjugates

The rate of nitrosation of dihexylamine is enhanced when the reaction is carried ut in the presence of micelles containing bile acid conjugates or bile acid conjugates and lecithin. The nitrosation of smaller dialkylamines is not affected. The nitrosation of dihexylamine under these conditions is inhibited by alpha-tocopherol at pH 3 or pH 5. At pH 3 the reaction is inhibited by ascorbic acid, while at pH 5 it is inhibited by equimolar concentrations of ascorbic acid, but accelerated by higher concentration of ascorbic acid. The effect of ascorbic acid at pH 5 depends on the presence of oxygen and sulfamate.     

浮选泡沫图像主成分的分类与识别

通过对大量浮选泡沫图像的分析,获得能够表示泡沫层的特征参数。采用灰度共生矩阵法提取参数特征并对特征参数进行正交变换处理,然后用BP神经网络进行分类,获得不同类别的浮选效果。研究结果表明,对特征参数进行正交变换修正后,大大提高了分类识别的正确率。     

热处理对纳米氧化锆粉末性能的影响

采用共沉淀法制备纳米ZrO2粉末,对其进行不同温度下的热处理,并对经过热处理的粉末进行物理性能及形貌的测试分析。对经过热处理的粉末进行等离子球化处理,并对其形貌进行观测。采用等离子喷涂方法制备ZrO2涂层,对涂层形貌进行观测。结果表明在适当温度对ZrO2进行热处理可提高粉末松装密度、流动速率及表面光洁度,提高粉末和涂层的综合性能。