N,N-亚甲基双丙烯酰胺对碳酸钙形貌的调控

以N,N-亚甲基双丙烯酰胺为添加剂对碳酸钙晶体进行调控,用X-射线粉末衍射仪(XRD)、红外吸收光谱(FT-IR)和扫描电子显微镜(SEM)对碳酸钙晶体的晶型和形貌进行了表征。结果显示,当加入0.1gN,N-亚甲基双丙烯酰胺,并且pH值为4.0时,碳酸钙晶体的形貌呈多层球状;当加入0.005gN,N-亚甲基双丙烯酰胺,且pH值为8.0时,碳酸钙晶体的形貌出现花状,但晶体的晶型都是方解石。     

柠檬酸钠的应用与制备方法研究

为进一步完善柠檬酸钠的制备方法,对影响柠檬酸钠产品质量和产率的一些工艺参数进行了研究和优化。通过一系列实验研究,确定了最佳工艺条件:最适宜的投料时间为20 min、柠檬酸钙投料结束时反应液最适宜的pH值为10.0、浓缩前柠檬酸钠溶液的pH值要调整到6.5-6.7、活性炭最适宜的用量为原料碳酸钠的1/20。同时介绍了柠檬酸钠在各领域的应用。     

尿液微晶的成分分析

利用X射线衍射法和傅立叶红外光谱法对16例结石病人和24例正常人尿液微晶进行了对比研究,从尿液抑制剂和尿液微晶在尿路中的滞留等角度分析了尿液微晶和结石形成的关系.结果表明,正常人尿液微粒以结晶态物质为主,其中以磷酸铵镁为主要成分的占66.7%,尿酸为主的占16.7%,一水草酸钙(COM)和β-磷酸三钙混合物为主的占16.7%;在结石病人中,尿液微晶以COM为主要成分的占33.3%,以磷酸八钙为主的占33.3%,以COM和β-磷酸三钙的混合物为主的占16.7%,以β-磷酸三钙和非晶态物质的混合物为主的占16.7%.     

Pannexins and gap junction protein diversity

Gap junctions (GJs) are composed of proteins that form a channel connecting the cytoplasm of adjacent cells. Connexins were initially considered to be the only proteins capable of GJ formation. Another family of GJ proteins (innexins) were first found in invertebrates and were proposed to be renamed pannexins after their orthologs were discovered in vertebrates. The lack of both connexins and pannexins in the genomes of some metazoans suggests that other, still undiscovered GJ proteins exist. In vertebrates, connexins and pannexins co-exist. Here we discuss whether vertebrate pannexins have a nonredundant role in animal physiology. Pannexin channels appear to be suited for ATP and calcium signaling and play a role in the maintenance of calcium homeostasis by mechanisms implicating both GJ and nonjunctional function. Suggested roles in the ischemic death of neurons, schizophrenia, inflammation and tumor suppression have drawn much attention to exploring the molecular properties and cellular functions of pannexins. Received 22 April 2007; received after revision 9 September 2007; accepted 19 September 2007     

Calcium imaging of muscle cells treated with snake myotoxins reveals toxin synergism and presence of acceptors

Snake myotoxins have a great impact on human health worldwide. Most of them adopt a phospholipase A2 fold and occur in two forms which often co-exist in the same venom: the Asp49 toxins hydrolyse phospholipids, whilst Lys49 toxins are enzymatically inactive. To gain insights into their mechanism of action, muscle cells were exposed to Bothrops myotoxins, and cytosolic Ca²⁺ and cytotoxicity were measured. In both myoblasts and myotubes, the myotoxins induced a rapid and transient rise in cytosolic [Ca²⁺], derived from intracellular stores, followed, only in myotubes, by a large Ca²⁺ influx and extensive cell death. Myoblast viability was unaffected. Notably, in myotubes Asp49 and Lys49 myotoxins acted synergistically to increase the plasma membrane Ca²⁺ permeability, inducing cell death. Therefore, these myotoxins may bind to acceptor(s) coupled to intracellular Ca²⁺ mobilization in both myoblasts and myotubes. However, in myotubes only, the toxins alter plasma membrane permeability, leading to death. Received 21 January 2009; received after revision 05 March 2009; accepted 11 March 2009     

CTAB在纳米CaCO3表面吸附引起的界面性质变化

利用十六烷基三甲基溴化铵(CTAB)对纳米CaCO3进行表面改性.采用FTIR、XRD、TG-DTG等分析技术对改性前后的纳米CaCO3进行表征,并通过Zeta电位、Brookfield黏度、吸油值、比表面积等实验对纳米CaCO3的表面改性效果进行评价.分析结果表明,CTAB在纳米CaCO3的表面形成化学吸附,经2.0%CTAB表面改性后,纳米CaCO3的界面性质发生了较大变化——纳米CaCO3的Zeta电位由负电性转向正电性,Brookfield黏度大大降低,吸油值由96.8 g降至53.1 g,比表面积从20.1m2/g增大到26.0m2/g.     

基于线粒体蛋白编码基因探讨飞虱科Delphacidae13属系统发育关系

飞虱科昆虫隶属于半翅目蜡蝉总科,是世界上最重要的农业害虫之一。昆虫的线粒体基因是昆虫分子与进化研究中常用且有效的分子标记。本研究基于线粒体蛋白编码基因探讨了飞虱科13属18种的系统发育关系,分别采用距离法、最大似然法和贝叶斯法构建的系统发育树得到的结论是一致的,即在飞虱科13属中,Ugyops属较为原始,处于系统树的基部,其余12个属聚为2支,Bambusiphaga属、Epeurysa属、Tropidocephala属和Saccharosydne属聚为一支,Peregrinus属、Perkinsiella属、Changeondelphax属、Chloriona属、Ishiharodelphax属、Sogatella属、Laodelphax属和Nilaparvata属聚为另一支。18种的进化地位和分类归属与传统分类结果基本一致。     

野生欧李果实中不同形态钙的含量

采用不同浸提剂（H2O,1mol／LNaCI,2％HAC,5％HCI）逐级提取,分析测定了野生欧李不同类型（大果型和小果型,小果型土壤施钙和叶面喷钙,大果型高位嫁接和低位嫁接）果实中的不同形态钙含量。结果表明：大果型和小果型果实中以活性钙（水溶钙和果胶钙）积累为主,不同形态钙含量大小为水溶钙含量〉果胶钙含量〉磷酸钙含量〉草酸钙含量〉剩余钙含量;小果型土壤施钙和叶面喷钙果实中总钙量增加,与实生小果型果实比较,活性钙组分下降,非活性钙组分增加;大果型高位嫁接和低位嫁接果实中不同形态钙组成比例大小并未改变,嫁接接口的高低影响果实中总钙量及不同形态钙的含量。研究提出,野生欧李果实中活性钙组分多,利于人体吸收和利用,是人体补钙之佳品。     

氯化钙、生姜和木瓜蛋白酶对牛肉嫩化效果的研究

采用正交试验方法和感官评定方法来优化和评价氯化钙溶液注射、生姜汁注射、木瓜蛋白酶溶液注射对牛肉嫩度等的影响.试验结果表明:氯化钙溶液的浓度和注射量、生姜汁的注射量、木瓜蛋白酶溶液的浓度和处理时间显著影响牛肉的嫩度(P<0.05).在这3种牛肉嫩化方法中,木瓜蛋白酶溶液注射的嫩化效果最好.     

诱导HAP结晶回收污水中磷主要影响因素分析

为了从污水中回收磷,采用以方解石为晶种在流态化结晶反应柱中诱导羟基磷酸钙(HAP)结晶的方法,考察了反应时间、反应温度、晶种投加量、pH值、Ca/P摩尔比、曝气量对诱导HAP结晶效果的影响.试验结果表明:该诱导结晶反应属于准一级反应,反应的活化能为5.96kJ/mol;pH值对HAP诱导结晶反应影响较大,当pH>8.5时可获得较好的磷回收率.最佳工艺参数为:当进水中磷浓度为20 mg/L、pH为9、反应时间为100 min、Ca/P摩尔比2.5、晶种投加量为60 g/L、反应温度为室温(20±1)℃、曝气量为270 L/h时,诱导结晶反应柱内磷回收率可达92.5%.以上结果表明,以投加晶种诱导HAP结晶的方式回收污水中的磷是可行的,与反硝化同步脱氮除磷工艺耦合将有助于提高污水处理效果和资源回收再利用.