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1.
硝酸铈对钙调素及调节蛋白Ca^2+—ATP酶基因表达的影响   总被引:5,自引:2,他引:3  
运用逆转录聚合酶链式反应研究了硝酸铈对大白鼠肝脏CaMⅠ,PMCA1b基因表达的影响,腹腔注射高、低浓度硝酸铈均不会引起CaMⅠ,PMCA1b基因表达的变化,提示硝酸铈对钙调素,Ca^2 -ATP酶的影响可能仅处于转录后水平。  相似文献   

2.
运用逆转录聚合酶链式反应研究了硝酸铈对大白鼠肝脏CaMⅠ ,PMCA1b基因表达的影响。腹腔注射高、低浓度硝酸铈均不会引起CaMⅠ ,PMCA1b基因表达的变化 ,提示硝酸铈对钙调素、Ca2 ATP酶的影响可能仅处于转录后水平。  相似文献   

3.
铈硝酸盐及其硝酸铵复盐的结晶制法及性质   总被引:5,自引:0,他引:5  
通过对硝酸铈、硝酸铈铵复盐的制备,叙述了硝酸铈的溶解度[1]、复盐形成等性质, 分析了结晶方式不同对铈硝酸盐及其硝酸铵复盐产品质量的差别, 指出通过改变其传统的结晶法制备工艺, 提高产品质量具有重要的现实意义.  相似文献   

4.
在Ni-Co-P化学镀液中添加硝酸铈,研究硝酸铈对Ni-Co-P镀层组织结构和性能的影响。利用扫描电子显微镜、X射线衍射仪、电化学工作站和显微硬度计,与常规化学镀层进行比较,观察和分析了硝酸铈对化学镀Ni-Co-P镀速、镀层形貌、结构、硬度和耐蚀性的影响。实验结果表明:采用添加硝酸铈的镀液施镀后,获得的Ni-Co-P镀层均匀致密,耐蚀性提高。镀层XRD衍射出现尖锐状衍射峰,呈微晶衍射特征。500℃热处理后,Ni-Co-P合金镀层完全转变成晶态,产生硬化相Ni3P。500℃热处理后,镀层硬度明显提高。  相似文献   

5.
为探讨稀土元素铈对香气前体物质及烤烟生长的影响及规律,本研究以云烟87为研究对象,采用盆栽试验,研究了硝酸铈(0, 15,30, 45, 60 mg·L-1)对烤烟烟叶香气前体物质含量(质体色素含量、多酚类物质含量)、化学成分含量、和生长(光合特性及农艺性状)的影响。结果表明,硝酸铈对叶绿素a、类胡萝卜素、叶绿素a+叶绿素b、新绿原酸、隐绿原酸、云香苷、总酚、还原糖、总糖等9种物质的含量及两糖比、糖碱比、氮碱比、钾氯比、蒸腾速率、气孔导度、净光合速率呈现出“低促高抑”的作用,即“Hormesis”效应,随着硝酸铈浓度的增加氯含量和根体积呈升高的趋势,莨菪亭和全磷含量呈下降的趋势。本研究中,15 mg·L-1硝酸铈促进烟叶质体色素含量和多酚类物质含量的积累,15~45 mg·L-1硝酸铈利于改善烟叶化学品质,30 mg·L-1硝酸铈增强烟叶光合作用,15~30 mg·L-1硝酸铈对地上部烟株的株高、茎围和叶面积有积极作用,60 mg·L-1硝酸铈促进烟株根系...  相似文献   

6.
采用现代核磁共振技术中魔角旋转方法,通过分析腹腔注射给药2,10和50 mg.kg-1体重剂量硝酸铈48 h后大鼠肝和肾组织MAS1H NMR谱,由组织中内源性代谢物浓度的变化研究了硝酸铈在动物体内的急性毒性,并利用模式识别技术对硝酸铈急性生物效应的NMR marker进行了研究。较高剂量组肝组织中的甘油三酯、乳酸、肝糖原和肾组织中的甘油三酯、甘油磷酸胆碱、甜菜碱等重要内源性代谢物的核磁共振谱峰强度发生了明显的变化,意味着动物体内的代谢出现异常:高剂量硝酸铈的引入可使动物肾脏和肝脏均受到损害,且受损程度随稀土剂量的增高而渐趋严重。  相似文献   

7.
报道一种制备芳基取代的1,4-二酮类化合物的温和简便方法, 以乙腈水溶液为溶剂, 硝酸铈铵为氧化剂, 对芳基取代的β-酮酸酯进行氧化偶联, 最高可以94%的产率得到双分子二聚产物, 为硝酸铈铵对1,3-二酮类化合物的氧化反应机理提供了有力证据.  相似文献   

8.
以葡萄糖、丙烯酰胺和硝酸铈铵为原料制备介孔CeO_2   总被引:1,自引:0,他引:1  
以葡萄糖、丙烯酰胺和硝酸铈铵为原料, 采用水热法制备出大比表面的介孔CeO2. 研究了铈离子价态、原料组成、 水热处理温度和时间以及原料的加入方式等条件对样品性能的影响, 并运用XRD, FT-IR, N2吸脱附和TG-DTG等手段对样品进行了表征. 结果表明, 铈离子价态由三价到四价可使介孔CeO2的比表面有较大的增加. 单独采用葡萄糖(或丙烯酰胺)和硝酸铈铵为原料所制样品的比表面较小, 而当原料组成为葡萄糖、丙烯酰胺和硝酸铈铵时可制得比表面较大的介孔CeO2, 水热处理时间和原料的加入方式对介孔CeO2的性能有一定的影响, 150 ℃水热处理2 d可获得比表面为162 m2 · g-1 的介孔CeO2.  相似文献   

9.
对单环β-内酰胺和稠二环β-内酰胺化合物使用硝酸铈铵进行了N-保护基对甲氧苯基的氧化脱除。通过对Kronental氧化工艺的改进,使产物收率显著提高,操作更为简便。  相似文献   

10.
石鸿昌 《合成化学》1998,6(3):294-297
对单环β-内酰胺和稠二环β-内酰胺化合物使用硝酸铈铵进行了N-保护基对甲氧苯基的氧化脱除,通过对Kronenthal氧化工艺的改进,使产物收率显著提高,操作更为简便。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

16.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

17.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

18.
The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.  相似文献   

19.
20.
设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。  相似文献   

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