Enhancement of sulfide auto-oxidation by metal ion in artificial seawater and a seawater which is a possible source of aoshio

SUMMARY: Aoshio is hypoxic milky blue-green seawater observed in some eutrophic bays. Previous studies have shown that colloidal sulfur causes the coloration and that the source of aoshio water is attributed to coastal anoxic bottom water. Occurrences of aoshio have been reported in limited areas of coastal seawater, although hypoxic transparent water seems rather universal. Promotion in auto-oxidation of sulfide by metal ions in seawater was investigated to explain the occurrences of aoshio. Artificial seawater containing 10 μM metal ion was assayed for the sulfide oxidation rate. The velocity constant which represents the oxidation rate within the initial 30 min and the amount of reacted sulfide in 2 h were determined by oxygen monitoring and sulfide quantification, respectively. Fe²⁺ and Cu²⁺ enhanced the initial 30 min reaction. Fe²⁺, Fe³⁺ and Ni²⁺ increased the amount of reacted sulfide in 2 h, forming whitish turbid water. Seawater from a suspected source of aoshio water was also assayed for the auto-oxidation rate of sulfide. The oxidation rate in water from 12 m depth was 13–19 times higher than the artificial seawater without an addition of heavy metal ions. More than 15% of the oxidation rate in 12 m deep seawater was explained by dissolved iron in the seawater.     

不同方法构建磺胺二甲氧嘧啶免疫抗原的比较研究

为探讨合成磺胺二甲氧嘧啶(SDM)免疫抗原的有效途径,采用重氮偶合法和戊二醛法分别合成SDM免疫抗原,并对其结构特征、光谱特征和SDM结合比进行比较.结果表明,在合成SDM-BSA中采用重氮偶合法比戊二醛法好.     

Genotype evaluation,muscle histopathology and ultrastructure in a Duchenne muscular dystrophy animal model

AIM: To evaluate the genotype , muscle histopathology and ultrastructure in dko mice. METHODS: Dystrophin/Utrophin-deficient double knockouts (dko) mice were obtained from university of Oxford, UK. Genotype of filial generation of heterozygote was evaluated by PCR-SSP. HE staining and fluorescent immunohistochemistry by SABC-Cy3 were used to detect striated muscle of dko mouse, and the muscle ultrastructure was observed by transmission electron microscope(TEM). RESULTS: In 112 filial generation mice, there were 28 mdx (25.0%), 26 dko (23.2%) and 58 heterozygote (51.8%), which coincided with the law of Mendelian inheritance. HE staining showed that the myocytes were not very uniform, there were phenomenon of round outline, centrally nucleated fibers, widening interspace, inflammatory cell infiltration and connective tissue proliferation in dko mice. There were no any immunofluorescent expression of dystrophin and utrophin in sarcolemma in dko mice. TEM showed sarcolemma breakage, separation and edema, and loose myofibril texture, inflammatory cell infiltration and connective tissue proliferation in dko mice. CONCLUSION: PCR-SSP is a very quick and accurate way for genotype evaluation of filial generation. The pathophysiology of dko mouse was very similar to Duchenne muscular dystrophy (DMD), and dko mouse is an ideal animal model for study of DMD clinical therapy.     

中国上市公司多元化经营绩效的实证分析

通过随机抽样,计算我国57家上市公司1998年-2002年的平均盈利指标和风险指标,根据各公司多元化熵值的大小对样本总体进行分组,分析多元化程度对企业绩效的影响.研究发现1.多元化程度越高,公司的平均净资产收益率越高;2.多元化经营降低了公司收益率的波动水平;3.资产规模越小的公司越倾向于选择多元化经营.     

槟榔红色素的抗氧化活性

测定槟榔红色素(areca red pigment,AP)对 DPPH·和·OH的清除能力、对脂质体过氧化的抑制能力、对Fe2+的络合能力,并测定其还原能力.结果表明:槟榔色素对DPPH·、·OH的清除能力较强:对脂质体过氧化的抑制能力很强,抑制率高达79.84%;与VE、没食子酸(gallic acid,GA)、BHT相比,槟榔色素的还原力、对Fe2+的络合能力较弱.说明槟榔红色素是较好的抗氧化剂.     

精梳棉卷成卷过程中起泡问题分析

介绍了成卷工艺对棉卷结构的影响以及棉卷成卷过程中起泡现象与准备工艺的关系.分析了棉卷成卷工艺过程中起泡过程和起泡原因,提出了防止起泡的措施.     

鼠李糖制备新工艺研究

采用正交设计方法探讨发酵法从芦丁水解液里提取制备鼠李糖的最佳制备工艺,优选出鼠李糖纯度达到99%以上的最佳制备工艺为:温度30℃,pH值5.0,酵母量为母液的2%。     

丰本生力酵素饲喂肉猪试验研究

选用60日龄杜洛克、长白仔猪，Ⅰ组为试验组，Ⅱ组为对照组。对照组饲养基础日粮，试验组在对照组的基础上添加1％的丰本生力酵素。结果表明：平均日增重试验组均高于对照组，其增长幅度杜洛克为13．1％，长白猪为8．12％。饲料转化率差异不显著，但瘦肉率试验组比对照组提高了13．1％。经济效益明显提高，杜洛克试验组比对照组提高了4．8％，长白猪试验组比对照组提高了5．3％。