柴胡和红花提取液在盐酸介质中对碳钢的缓蚀作用

采用索氏提取法分别从中草药柴胡和红花中提取了两种缓蚀剂,采用失重法和电化学法研究了两种缓蚀剂在0.1mol/L 盐酸介质中对碳钢缓蚀作用,比较了缓蚀剂不同浓度、温度和腐蚀浸泡时间等因素对碳钢缓蚀率的影响.结果表明,提取的两种缓蚀剂对碳钢都具有良好的缓蚀作用,从红花中提取的缓蚀剂缓蚀率为83.5%,极化曲线表明这两种缓蚀剂为混合抑制型缓蚀剂.     

非常规饲料玉米柠檬酸渣的开发利用

开发非常规饲料是缓解饲料资源不足、降低畜禽养殖成本、提高畜牧业经济效益的重要途径。玉米柠檬酸渣是柠檬酸生产企业副产品,含有丰富的营养物质,用作畜禽配合饲料原料有着很好的开发前景。文章对玉米柠檬酸渣饲料资源特点、营养特性、在动物生产中应用效果与研究现状、存在问题等进行了详细分析,并提出了开发利用时需要解决的问题。     

High-level soluble expression of the hemA gene from Rhodobacter capsulatus and comparative study of its enzymatic properties

The Rhodobacter capsulatus hemA gene, which encodes 5-aminolevulinic acid synthase (ALAS), was expressed in Escherichia coli Rosetta (DE3) and the enzymatic properties of the purified recombinant ALAS (RC-ALAS) were studied. Compared with ALASs encoded by hemA genes from Agrobacterium radiobacter (AR-ALAS) and Rhodobacter sphaeroides (RS-ALAS), the specific activity of RC-ALAS reached 198.2 U/mg, which was about 31.2% and 69.5% higher than those of AR-ALAS (151.1 U/mg) and RS-ALAS (116.9 U/mg), respectively. The optimum pH values and temperatures of the three above mentioned enzymes were all pH 7.5 and 37 °C, respectively. Moreover, RC-ALAS was more sensitive to pH, while the other two were sensitive to temperature. The effects of metals, ethylene diamine tetraacetic acid (EDTA), and sodium dodecyl sulfate (SDS) on the three ALASs were also investigated. The results indicate that they had the same effects on the activities of the three ALASs. SDS and metal ions such as Co²⁺, Zn²⁺, and Cu²⁺ strongly inhibited the activities of the ALASs, while Mn²⁺ exerted slight inhibition, and K⁺, Ca²⁺, Ba²⁺, Mg²⁺, or EDTA had no significant effect. The specificity constant of succinyl coenzyme A [(k _cat/K _m)_S-CoA] of RC-ALAS was 1.4989, which was higher than those of AR-ALAS (0.7456) and RS-ALAS (1.1699), showing its high catalytic efficiency. The fed-batch fermentation was conducted using the recombinant strain containing the R. capsulatus hemA gene, and the yield of 5-aminolevulinic acid (ALA) achieved was 8.8 g/L (67 mmol/L) under the appropriate conditions.     

Synthesis of Enriched 10B Boric Acid of Nuclear Grade

An economic and effective method of preparing enriched 10 B boric acid was established by chemical reaction of enriched 10BF3 and CaCO3. A process of boron trifluoride reacting with water was investigated under certain conditions. Calcium carbonate was selected to counteract hydrofluoric acid followed on. Some key operation factors were investigated, such as temperature, reaction time and the ratio of CaCO3 to 10BF3. The results showed that the yield of enriched 10 B boric acid could reach 97. 2% and the purity was up to 94. 1% under the following conditions: the temperature was 50—60,℃, the reaction time was 28 h and the ratio of CaCO3 to 10BF3 was 4. In addition, after recrystallization and titration analysis, the purity of the product could reach over 99. 2% from 94.1%.     

HPLC 测定不同产地茯苓中的茯苓酸含量

利用HPLC测定并比较全国各主要产地茯苓药材中茯苓酸含量.方法：采用waters symmetry C18（5μm,4.6×150mm）色谱柱,以乙腈和0.5%磷酸水溶液为流动相,分析测定了全国11个产地的茯苓药材中茯苓酸的含量.结果：在既定色谱条件下线性范围良好,该方法稳定性、重现性及茯苓酸加样回收率符合要求.鄂豫皖及云贵地区产地的茯苓药材茯苓酸含量高于其他产区,质量较好.结论：该方法准确、稳定,可为茯苓药材质量控制提供一定依据和科学保证.     

哌嗪的氨基酸缀合物的合成、表征及抑菌活性研究

哌嗪是化工生产的常用化合物,也是重要的医药中间体。近些年来,哌嗪类衍生物作为药物的研发引起了人们的广泛关注。本文以哌嗪为起始原料,将4种氨基被保护的氨基酸导入哌嗪的N-1和N-4位,再脱去保护基,合成了8种哌嗪的氨基酸缀合物,并通过IR和1H NMR对所合成的氨基酸缀合物进行了结构表征。然后对目标产物进行了野生型大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)抑菌活性测试。结果表明化合物PP-1a、PP-2a、PP-1b、PP-2b、PP-1c、PP-2c、PP-2d对Staphylococcus aureus具有一定的抑菌效果并且抑菌作用随化合物浓度的升高而增强。     

钯炭催化剂的制备与性能研究

用酸预处理的活性炭作载体制备Pd/C催化剂;用XRD、N2-物理吸脱附、TEM等方法进行催化剂的结构表征.在催化剂的性能研究中发现:催化剂的活性与载体活性炭的种类、预处理和制备方法有很大的关联性.经混合酸预处理的活性炭作载体制备的Pd/C在同时具有硝基与双键的4,4'-二硝基二苯乙烯-2,2'-二磺酸二钠的催化加氢制4,4'-二氨基二苯乙烯-2,2'-二磺酸的反应中具有很好的选择性.     

棒叶落地生根叶片中抗坏血酸-谷胱甘肽循环对干旱与复水的响应

棒叶落地生根植株干旱20d与70d,并对干旱70d的植株进行复水处理,测定叶片中抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）与脱氢抗坏血酸还原酶（DHAR）的活性,以及抗坏血酸（AsA）与谷胱甘肽（GSH）含量的变化。结果表明,随着干旱进行,APX与DHAR活性均显著增加,GR活性先增加后降低;AsA、脱氢抗坏血酸（DHA）含量与AsA／DHA比值均显著增加,GSH含量增加但不显著,氧化型谷胱甘肽（GSSG）含量显著增加,GSH／GSSG比值增加但不显著。复水后叶片中APX、DHAR活性显著低于干旱70d时,GR活性高于干旱70d时;AsA、DHA含量与AsA／DHA比值显著低于干旱70d时,GSH、GSSG含量与GSH／GSSG比值低于干旱70d时,但差异不显著。可见,在棒叶落地生根遭遇干旱时,AsA—GSH循环系统清除活性氧的能力提高。     

玉米油酸价的影响因素研究

玉米油料未完全成熟、霉变及加工、储存不当时,会引起油脂的分解而产生游离脂肪酸,从而降低油脂的品质。本研究对影响玉米油酸价的霉变、热损伤、生产加工过程、储存环节等因素进行了研究,通过对玉米油料贮藏、加工过程中酸价定期跟踪检测,初步探索其变化规律。研究结果表明,霉变、热损伤、生产加工过程、储存环节对玉米油的酸价影响都很显著,空气、水分、光照和温度等条件对油样酸价也有较大影响。结果为降低玉米油酸价、提高经济效益提供了理论依据。     

枸橼酸作用下纳米铁氧化物晶体的形成研究

以FeSO4为原料,NaOH为沉淀剂,加入添加剂构橼酸,用空气氧化法合成纳米铁氧化物,在不同pH值下考查添加枸橼酸对纳米铁氧化物形成的影响.试验结果表明,当pH=8～9时,少量构橼酸有利于铁氧化物品体的生长;随着枸橼酸浓度的增大,铁氧化物结晶粒子半径逐渐减小,最终铁氧化物品体消失.