疏水性固体酸Zr(SO4)2·4H2O/AC催化合成柠檬酸三乙酯

将Zr(SO4)2·4H2O(ZS)负栽在活性炭(AC)上制备疏水性固体酸ZS/AC催化剂,用于催化合成柠檬酸三乙酯.探讨了各影响因素对柠檬酸三乙酯收率的影响.结果表明,当四水硫酸锆的负载量为30%、催化剂处理温度为110℃、催化剂用量为柠檬酸质量的4%、酸醇摩尔比为1:5.5、100℃反应5 h时,产物收率可达97.6%.催化剂重复使用四次后产率仍保持在93%以上,且易分离,不污染环境.     

褐藻酸钠不同脱色方法的比较研究

以海带为原料提取褐藻酸钠,并对褐藻酸钠的脱色方法进行研究.分别采用活性碳、次氯酸钠、过氧化氢和大孔树脂NAR-9、ADS-22、ADS-8对褐藻酸钠进行脱色.通过对多糖脱色率比较发现,四种方法对褐藻酸钠均有脱色效果.次氯酸钠脱色率较高但多糖保留率较低,树脂脱色法明显优于次氯酸钠、过氧化氢和活性发.     

木质纤维素类生物质酸水解研究进展

木质纤维素中纤维素和半纤维素经酸水解可转化为糖,糖进一步可生产燃料乙醇和其他化工产品。因此,木质纤维素酸水解制备糖是纤维素转化过程中关键步骤。本文综述了硫酸、盐酸、硝酸、磷酸、马来酸等无机、有机酸水解木质纤维素类生物质研究进展,对各种酸水解工艺的优缺点进行了分析和比较,指出了木质纤维素类生物质酸水解的研究方向。     

铜合金三酸抛光微观效果研究

通过扫描电子显微镜微观观察的方法对三酸化学抛光液中各组分对铜合金表面抛光效果的影响进行了研究.结果表明,采用微观观察法能够更直观有效地研究各组分对铜合金表面抛光效果的影响,在此基础上,获得铜合金表面最佳抛光液:磷酸200~300ml/L、硫酸200~400ml/L(磷酸+硫酸500~600ml/L)、硝酸200~250ml/L(紫铜)、40~150ml/L(黄铜)、盐酸5~15ml/L.经处理的铜合金表面不仅外观光亮、微观平整,而且铜合金表面制备的转化膜中性盐雾测试时间更长、防腐性能更好.根据扫描电子显微镜观察铜合金微观形貌获得最佳抛光液组成的方法,简单方便、准确有效     

微波辐照载催化剂活性炭脱除烟气中NO的实验研究

微波连续辐照活性炭脱除烟气污染物中NO虽然具有很高的脱除效率,但反应温度较高,会造成较高的炭损失,在活性炭中加入催化剂可以降低反应温度、增进反应的选择性.本文利用微波反应器研究了不同催化剂加入对烟气脱硝的影响.研究发现,催化剂的加入会明显降低相同脱除效率下脱硝所需要的微波功率,不同催化剂的加入所引起的效果亦有差异,铜基催化剂的催化作用更明显.加入铜基催化剂后,脱硝反应温度降低约200℃,可提高脱除效率25%左右.采用X射线衍射（XRD）对活性炭进行了微观表征分析,分析结果显示出活性炭表面存在催化剂活性成分.     

短程高效回收废锂离子电池中铜金属的技术及机理研究

信息通讯技术和电动汽车产业的快速发展产生了大量的废锂离子电池,其资源化回收成为资源可持续利用及环境保护的重要手段.但传统的回收过程工艺繁琐,资源化效率较低阻碍了产业的良性发展.为了缩短废锂离子电池的资源化工艺,选择离子液体作为加热介质,通过熔化黏结剂,分离铜箔和负极材料实现对废锂离子电池中铜金属的回收.回收过程发生急剧的热对流和热传导过程,利用搅拌机快速运转强化了热对流的过程和机械力分离正极材料,基于传热理论傅里叶定律建立了热传递过程数学模型.通过详细实验研究发现,当加热温度180℃、搅拌速度350 r/min、停留时间30 min,可以实现铜金属的短程高效回收.本技术的研发大大促进了铜铝金属的高效回收,打通了废锂离子电池的闭环供应链.     

空气/水双源热泵废热再用热水装置的性能分析

提出一种新型空气/水双源热泵废热再用热水装置,其热泵系统可用空气源或水源或空气源-水源联合3种模式加热水.自来水分两级加热,先由废热水预热,后经热泵再加热;废热水热能分两级回收,先供自来水预热,后作热泵水源循环热源.采用无量纲对比态分析法,并参考了实验值拟合的空气源热泵、水源热泵性能系数计算式,以及废热回收-预热器的增益系数计算式,导出了装置6种运行模式的性能系数计算式,分析了废热回收-预热器的换热与热泵的吸热、放热关联的不同工况特性,为选择最优运行模式和参数提供参考.分析和实验表明,本装置的性能系数在冬季也能到达4～5.5,为普通空气源热泵热水器2倍,废水余热利用率优于废水仅作预热或热泵热源情况,节能效益明显.另外把无量纲对比态分析法引进到热泵循环性能分析中,也有理论意义和实际使用价值.     

MD 模拟研究带静电ACF 对甲醇的吸附

为了探索静电荷在极性分子的物理吸附过程中的控制作用, 对甲醇在带静电荷的活性炭纤维(ACF)纳米孔中的吸/脱附情况进行了分子动力学(MD)模拟研究. 在引入静电荷的中孔ACF/甲醇吸附系统中, 从模拟结果可以观测到孔内的甲醇分子扩散到吸附位的时间缩短、吸附冷凝的准液态甲醇密度增大、甲醇分子的空间排列有取向性、达到吸附平衡时系统能量显著降低等特殊现象, 表明了静电荷增强了中孔ACF 对甲醇分子的吸附作用, 使吸附强度、稳定性和有序性有所提高, 能够提高吸附容量和加快吸附速率. 系统达到吸附平衡后再消除静电荷, 升温至60℃左右进行模拟, 可以观察到比较明显的脱附趋势.     

白菜病害生防原生质体融合菌株的筛选

为了获得同时具有白菜软腐病和黑斑病生防功能的原生质体融合菌株,对白菜软腐病生防菌株芽孢杆菌KR和白菜黑斑病生防菌株假单胞菌B13的融合子进行了筛选.结果表明:2.0单位/mL的硫酸妥布霉素和5×10-3 g/mL的氯霉素可分别抑制假单胞茵B13和芽孢杆菌KR,培养基中添加这两种抗生素可选出融合子.对得到的182个融合子进行传代,连续传10代后,得到一株能稳定遗传的融合子KB1.     

金银藤挥发油成分的气-质联用分析与化学计量学解析

目的 定性、定量分析金银藤挥发油成分.方法 采用气相色谱-质谱进行检测,通过化学计量学解析法对二雏色谱/质谱数据进行解析,得到各组分的纯色谱曲线和质谱,从而实现对金银藤挥发油成分的定性、定量分析,并结合程序升温保留指数来鉴定化合物.结果 金银藤的挥发油鉴定了39个成分,定性组分含量占金银藤挥发油成分总含量的94.54%.结论 全银藤挥发油的主要成分为十六烷酸（45.86%）、9,12-十八碳二烯政乙酯（39.02%）、十四烷酸（1.8%）、十五烷酸（1.07%）、十八烷酸（1.02%）.     

Über die Umwandlung von markiertem Glykokoll durchFusarium lycopersici

Summary C¹⁴-methylene-labelled glycine was added to growing mycelium ofFusarium lycopersici. Young, rapidly growing mycelium converts about 2% of the radioactivity into carbon dioxyde; with older mycelium, the carbon dioxyde is almost inactive. In the protein hydrolysate, labelled glycine, serine, valine and leucine and small quantities of aspartic acid and glutamic acid were found. Valine and leucine apparently have not been identified before as metabolic products of glycine.     

Molecular and Cellular Basis of Regeneration and Tissue Repair

The Xenopus tadpole is a favourable organism for regeneration research because it is suitable for a wide range of micromanipulative procedures and for a wide range of transgenic methods. Combination of these techniques enables genes to be activated or inhibited at specific times and in specific tissue types to a much higher degree than in any other organism capable of regeneration. Regenerating systems include the tail, the limb buds and the lens. The study of tail regeneration has shown that each tissue type supplies the cells for its own replacement: there is no detectable de-differentiation or metaplasia. Signalling systems needed for regeneration include the BMP and Notch signalling pathways, and perhaps also the Wnt and FGF pathways. The limb buds will regenerate completely at early stages, but not once they are fully differentiated. This provides a good opportunity to study the loss of regenerative ability using transgenic methods.     

Action of GABA and glycine on the membrane potential of cultured astrocytes and the extracellular K+-concentration

Summary The depolarization of cultured astrocytes by GABA and glycine correlates in amplitude and time course with the increase of the extracellular K⁺-concentration during perfusion with these amino acids. It is suggested that the glial depolarization is caused by an efflux of K⁺ from neighbouring neurones activated by the amino acid transmitters.     

Effect of (+)-catechin on renal and intestinal transport.

The ability of dog renal cortex slices to accumulate beta-methyl-glucoside or glycine is enhanced by the flavonoid (+)-catechin at a concentration of 3.5 mM. This stimulatory effect is apparently due to a decreased rate of efflux of either substrate. On the other hand, the uptake of p-amino-hippuric acid and N1-methyl-nicotinamide is inhibited by (+)-catechin. The drug at the same concentration is without action on amino-acid transport by guinea-pig intestine in vitro.     

Satellite cells in the regenerated and regrafted skeletal muscles of rats

Soleus (SOL) muscles were grafted into extensor digitorum longus (EDL) muscle beds (EDL-first-graft). Sixty days later, some mature EDL-first-grafts were regrafted into their own beds (EDL-second-grafts). Fully regenerated muscle fibers and satellite cells were observed in both types of mature grafts. The ratios of satellite cell nuclei per total nuclei (myonuclei and satellite cell nuclei) were 4.81 +/- 0.47% for EDL-2nd graft, 4.26 +/- 0.51% for EDL-1st-graft, 4.30 +/- 0.33% for control SOL, and 3.30 +/- 0.18% for control EDL. It is thought that satellite cells are required for the repeated activity of muscle fiber regeneration. The persistance of satellite cells in EDL-second-grafts suggests that satellite cells are not depleted during the first grafting, making second-grafts possible.     

Satellite cells in the regenerated and regrafted skeletal muscles of rats

Summary Soleus (SOL) muscles were grafted into extensor digitorum longus (EDL) muscle beds (EDL-first-graft). Sixty days later, some mature EDL-first-grafts were regrafted into their own beds (EDL-second-grafts). Fully regenerated muscle fibers and satellite cells were observed in both types of mature grafts. The ratios of satellite cell nuclei per total nuclei (myonuclei and satellite cell nuclei) were 4.81±0.47% for EDL-2nd graft, 4.26±0.51% for EDL-1st-graft, 4.30±0.33% for control SOL, and 3.30±0.18% for control EDL. It is thought that satellite cells are required for the repeated activity of muscle fiber regeneration. The persistance of satellite cells in EDL-second-grafts suggests that satellite cells are not depleted during the first grafting, making second-grafts possible.     

The roles of endogenous retinoid signaling in organ and appendage regeneration

The ability to regenerate injured or lost body parts has been an age-old ambition of medical science. In contrast to humans, teleost fish and urodele amphibians can regrow almost any part of the body with seeming effortlessness. Retinoic acid is a molecule that has long been associated with these impressive regenerative capacities. The discovery 30 years ago that addition of retinoic acid to regenerating amphibian limbs causes “super-regeneration” initiated investigations into the presumptive roles of retinoic acid in regeneration of appendages and other organs. However, the evidence favoring or dismissing a role for endogenous retinoids in regeneration processes remained sparse and ambiguous. Now, the availability of genetic tools to manipulate and visualize the retinoic acid signaling pathway has opened up new routes to dissect its roles in regeneration. Here, we review the current understanding on endogenous functions of retinoic acid in regeneration and discuss key questions to be addressed in future research.     

Über den Einbau von Asparaginsäure in Peganin

Summary Aspartate-3-C¹⁴ (XIII) was administered to young plants ofAdhatoda vasica Nees. After a feeding period of 1 or 2 days, the isolated alkaloid peganine (=vasicine) (I) was degraded. The distribution of the radioactivity in the anthranilic acid (II) and glycine (XIV) obtained has been determined (Figure). Most of the radioactivity (80%) was localized in the glycine corresponding to the positions 1 and 2 of peganine. More radioactivity was recovered from position 2 of the alkaloid than from position 1. The labelling pattern is discussed. The results indicate either that aspartate or a closely related compound is an immediate precursor of peganine.     

Free amino acids in some tissues of marine crustacea

Summary Free amino acids contained in extracts of crustaceans were separated and determined quantitatively by ion exchange chromatography. In the hepatoprancreas of the brachyuran crustaceanCarcinus maenas, glycine, arginine, proline and alanine constituted 78.7% of the total amino acid pool. InEriphia spinifrons andMaja verrucosa, glycine, alanine, lysine and leucine comprised 54.9–66.9% of the total content. In the muscle tissue of the macruran crustaceaPalaemon, glycine, arginine, proline and alanine were the most common free amino acids and comprised 70–95% of the total content. The high concentrations of some amino acids in tissues of crustaceans may play a role in intracellular osmotic regulation and also in the maintenance of ionic hydrogen concentration.Acknowledgments. The author wishes to thank Mr R. Mari for his skillful help in the amino acid analyses and Miss G. Princivalli for typing the mansucript.     

The glycinergic inhibitory synapse

Glycine is one of the most important inhibitory neurotransmitters in the spinal cord and the brainstem, and glycinergic synapses have a well-established role in the regulation of locomotor behavior. Research over the last 15 years has yielded new insights on glycine neurotransmission. Glycinergic synapses are now known not to be restricted to the spinal cord and the brainstem. Presynaptic machinery for glycine release and uptake, the structure and function of postsynaptic receptors and the factors (both pre- and postsynaptic) which control the strength of glycinergic inhibition have been extensively studied. It is now established that glycinergic synapses can be excitatory in the immature brain and that some inhibitory synapses can corelease γ-aminobutyric acid (GABA) and glycine. Moreover, the presence of glycine transporters on glial cells and the capacity of these cells to release glycine suggest that glycine may also act as a neuromodulator. Extensive molecular studies have revealed the presence of distinct subtypes of postsynaptic glycine receptors with different functional properties. Mechanisms of glycine receptors aggregation at postsynaptic sites during development are better understood and functional implications of variation in receptor number between postsynaptic sites are partly elucidated. Mutations of glycine receptor subunits have been shown to underly some human locomotor disorders, including the startle disease. Clearly, recent work on glycine receptor channels and the synapses at which they mediate inhibitory signalling in both young and adult animals necessitates an update of our vision of glycinergic inhibitory transmission. Received 8 September 2000; received after revision 1 December 2000; accepted 21 December 2000