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Changes of cell wall components in relation to softening and lignifying of fresh-cut bamboo shoots (Phyllostachys heterocycla var. pubescens) was investigated. Increased activity of phenylalanine ammonia-lyase (PAL) was related to a rise of lignin content in the basal section but not in the middle and apical sections. PAL activity was also associated with an increase in phenolic content in the middle section, but not in the basal and apical sections. The softening process occurred mainly in the apical section, while lignification took place primarily in the basal section. In the middle section, both softening and lignification also occurred but to a lesser extent. 相似文献
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A Ziolkowski AS Shashkov AS Swierzko SN Senchenkova FV Toukach M Cedzynski KI Amano W Kaca YA Knirel 《Canadian Metallurgical Quarterly》1997,411(2-3):221-224
Structures of the O-specific polysaccharide chains of lipopolysaccharides from Proteus group OX strains (serogroups O1-O3) used as antigens in Weil-Felix test for diagnosis of rickettsiosis, were established. From them, the acid-labile polysaccharide of Proteus vulgaris OX19 (O1) is built up of the following branched pentasaccharide repeating units connected via a phosphate group: [structure in text] where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose (N-acetylquinovosamine). The basis of serospecificity of the Proteus group OX antigens and their cross-reactivity with human anti-rickettsial antibodies is discussed. 相似文献
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S Natsch YA Hekster A Keyser CL Deckers H Meinardi WO Renier 《Canadian Metallurgical Quarterly》1997,17(4):228-240
In the last few years a number of new anticonvulsants have been introduced into clinical practice mainly as add-on therapy in patients who do not become seizure-free while receiving established anticonvulsants. Up to now, no single drug has been shown to be more effective at controlling seizures of a particular type than another, so other factors such as mechanism of action, pharmacokinetics, dosage regimens or the spectrum of adverse drug reactions and interactions are used when making a choice between one agent and another. The mechanism of action of tiagabine and vigabatrin is very specific; both agents increase gamma-aminobutyric acid (GABA) levels through inhibition of reuptake and catabolism respectively. However, the mechanism of action of gabapentin is unknown and those of felbamate, lamotrigine and topiramate are not sufficiently clarified as yet, and may be multiple. Great advances have been made in improving the pharmacokinetic characteristics of these newer anticonvulsants. Gabapentin and vigabatrin exhibit relatively ideal pharmacokinetic properties as they are not bound to proteins, are excreted mostly unchanged in the urine and show linear pharmacokinetics. Lamotrigine possesses a highly variable elimination half-life depending on the co-medication. Tiagabine is highly protein bound and zonisamide shows nonlinear pharmacokinetics; both these drugs are extensively metabolised. Problematic drug interactions between newer anticonvulsants and other drugs in general occur rarely when these agents are given concomitantly. However, in common with most new drugs, there are very few data on the use of the newer anticonvulsants in women of childbearing age. Studies done so far on interactions with oral contraceptives used low anticonvulsant dosages for a very short time. The newer anticonvulsants elicit adverse reactions that, while not being unique, are particularly associated with that drug. For example, felbamate may cause aplastic anaemia and fulminant liver failure, lamotrigine is prone to cause skin rash, and oxcarbazepine may cause symptomatic hyponatraemia. Topiramate and zonisamide cause kidney stones, and vigabatrin may induce psychiatric syndromes. Although highly diverse in structure and activity, these newer drugs offer new possibilities for treating refractory epilepsy. However, since no single factor can dictate the choice of drug nor predict the success of treatment, prescribing of these rather expensive drugs has to depend upon careful consideration of the aims of treatment, the characteristics of the drug and the needs of the individual patient. 相似文献
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阐述了游离氯产生的原因及脱氯方法。介绍了新疆中泰化学(集团)股份有限公司华泰分公司通过对脱氯淡盐水pH值进行精细化控制,达到了降低成本、节能降耗的目的。 相似文献
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现有地表水源热泵换热器设计资料粗糙且不完全符合我国地表水的特点,应用误差较大.本文通过塑料螺旋管换热器设计计算简化数学模型的大量数值计算,可知在工程设计值范围内,影响其换热能力的显著因素是换热器进出口温差和地表水体流速,而换热介质种类、换热介质流速和地表水体温度等因素对换热器换热能力的影响不大.在此基础上,给出了供热、供冷工况的基本线算图和换热器进出口温差的修正系数公式、地表水体流速修正系数表.在保持基本线算图简便特性的同时,大大扩展了线算图的使用范围.本文结论可为我国地表水源热泵设计提供参考. 相似文献
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