首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
测定了24例甲亢治疗前后及30例健康对照的头发锌、硒、钒、锂及锗的含量,发现未治疗的甲亢头发锌、硒、钒、锂及锗含量较对照组低,Zn、Se、Li、Ge,P<0.001,V,P<0.01.甲亢经6~12周抗甲亢药物治疗后.头发中5种元素均较治疗前上升(P<0.001),且头发钒和锂含量治疗后已达到对照组水平,V,P>0.2,Li,P>0.1,而头发锌、晒及锗含量治疗后仍低于对照组(P<0 .001).结论:甲亢头发锌、硒、钒、锂及锗含量降低.经6~12周抗甲亢治疗可使头发钒及锂含量恢复正常水平,而其余3种元素则可能需要更长时间的抗甲亢治疗才能恢复至正常水平。  相似文献   

2.
P. Remuzon  M. Wakselman 《Tetrahedron》1977,33(23):3097-3103
A kinetic study of the alkaline hydrolysis and the imidazole-catalysed hydrolysis of a series of o - or p-acetoxybenzyl bromides and p-nitrophenyl ethers has been determined as a function of pH and temperature. The reactions were followed by disappearance of ester and by release of bromide or p-nitrophenolate anions. In both cases, the rates obtained were equal, and proportional to the ester and nucleophile concentrations. The formation of N- acetyl-imidazole intermediate, followed at 245 nm, as well as the observed deuterium isotope effect, correspond to a nucleophilic attack on the carbonyl group. When the acetoxy group is hindered, the reaction with hydroxide ion is slower, no catalysis can occur, and imidazole may react directly at the benzylic site of the molecule.  相似文献   

3.
N-Acetylmuramyl-L-alanyl-D-isogl (Muramyl dipeptide, MDP), the smallestimmunoactive fragment of the cell wall peptidoglycans, which exhibits diverse biologicalactivities such as adjuvant property. enhancement of host defence ability againstmicrobial infection as wei] as antiviral and antitumor potency' =. In tJle last decades.studies on the synthesis of analogs and the relationship between structure and activity ofMDP analogs have emerged since its first synthesis in 1975" 3' '. Because of…  相似文献   

4.
Asapowerfulandversatileone-electrontransferreductant,Sml,hasbeenappliedwidelyinorganicsynthesis'.OurpreviousworksonthereductionofnitrocompoundsandreductivecleavageofS-S,Se-Se,Te-TebondswithSml,'ledustoinvestigatethesimultaneousreductionofnitrogroupandS-SbondbySml,.Benzothiazolinesderivativesareimportantreagentsandusefulintermediatesinorganicsynthesisandpharmaceuticalchemistry.Forinstance,theycanbeusedasadditionagentsforphotographicemulsions",effectiveacaricides",antituberculousagents",lubr…  相似文献   

5.
抗肿瘤中药微量元素硒的研究   总被引:2,自引:0,他引:2  
与抗肿瘤作用关系密切的中药微量元素主要有Se、Ge、Zn、Cu、Fe、Mn、Mo、I、B、Si、Li等,本文介绍了近年来Se的研究。Se是人体健康必需的超微量元素.与某些地方病、癌的发生关系密切。是同时具备防癌和促免疫两种活性的理想防癌剂。大部分补气、补血、补肾、补阳等中药富含Se等微量元素,具有抗癌等药理作用.特别是人参等12种中药的抗癌作用尤明显。  相似文献   

6.
卡尔曼滤波分光光度法同时测定钢中钛和钼   总被引:3,自引:1,他引:3  
李华  李德亮 《分析化学》1993,21(2):218-220
本文采用卡尔曼滤波(KF)递推法,以苯基荧光酮-溴化十六烷基吡啶与钛,钼的显色体系同时测定钛和钼,同时以柠檬酸和抗坏血酸掩蔽干扰,并引入误差校正因子来校正加掩蔽剂后在所测波段范围内所造成的残余背景吸收,用于实际钢样分析,获得较满意的结果。  相似文献   

7.
The He(I) and MgKα photoelectron spectra are reported for the isomeric thiazoles, and He(I) spectra for the isomeric-thiadiazoles. Marked fine structure is apparent on some of the spectra. Comparison with the earlier spectra for thiophen and the azoles, and with ab initio calculations for the seven compounds, has led to assignment of the spectra. The calculations suggest that 1,3,4-thiadiazole is less aromatic than the other title compounds. As expected, the role of the 3ds orbitals is found to be that of polarisation functions for all of the compounds, but inclusion of these orbitals leads to much better agreement with the observed dipole moments, both in magnitude and direction.  相似文献   

8.
G Gottschalk 《Talanta》1979,26(8):657-663
Linear analytical functions covering at least a working range of one power of ten are the basis for useful determination procedures. The efficiency of the procedure is given by characteristic data such as constant magnitude of the analytical function, the standard deviation of the procedure and the determination limit. These can be evaluated by systematic standardization, Three simple tests are described to check the possibility of standardization, and a method is given for estimating values of the characteristic data, which requires only 2 sets of 4 experiments each. Thus preliminary work in the development of reliable procedures can be carried out purposefully, with only a few experiments.  相似文献   

9.
库仑滴定法测定有机硅样品中的氮含量   总被引:3,自引:0,他引:3  
谢择民  王清正 《分析化学》1993,21(2):206-208
本文利用库仑滴定法研究了高分子和低分子硅氮化合物及含氮有机硅样品中氮含量的测定,并研究和讨论了影响测定结果准确性的因素。  相似文献   

10.
Paeonivayin, A New Monoterpene Glycoside from Paeonia delavayi   总被引:4,自引:0,他引:4  
Paeoniarootbark,"Dan-Pi"inChinese,isoneofthemostimportantherbaldrugswhichhasbeenusedfortreatmentofmuscularspasm,chestpains,diarrhoea,bloodandliverdisordersaswellasageneralanalgesicintraditionalChinesemedicine.SignificantchemicalandpharmacologicalinvestigationshavebeenconductedonthedifferentspeciesofPaeonia'-',P.albifiora,P.anomala,P.lacli/loraandP.sloffflllicosa.Asoneofthemainsourcesof"Dan-Pi",theconstituentsofP.delayal'iFranch.havenotbeenstudied.Inthecourseofourstudyonpharmacologicallyac…  相似文献   

11.
测定了陶工I期尘肺患者的头发中Zn、Cu、Se、Ni、Fe、Mn、Mg7种金属元素,用陶工可疑患者作对照,建立Fisher判别方程,对陶工尘肺进行判别。自身回代正确率94.44%,前瞻性回代达83.33%,各其流行病学指标计算均属良好。  相似文献   

12.
Annonaceous acetogenins are considered as the main components with cytotoxicity inthe plants of Annonaceae family. The genus Uvaria is one of the main plants containingAnnonaceous acetogenins, and more than fifty acetogenins have been isolated from eightspecies of the title genus"', however, acetogenins with double bond in the aliphatic chainhas not yet been reported. In this paper we report the structure elucidation of calamistrinE (l), a new acetogenin bearing one double bond besides a tetr…  相似文献   

13.
急性脑血管病患者血清元素的测定   总被引:3,自引:1,他引:3  
采用高频等离子体发射光谱法测定了34例脑梗塞、33例脑出血和对照组27人血清锌、铜、锰、铬、镁、钼、锶、铁、钛、钡、镉和钙共12种元素的含量。结果显示脑梗塞和脑出血组血清锌和锌/铜比值显著高于对照组;锰和钼含量仅在脑梗塞组明显增高,锶仅在脑出血组显著增高,而其它几种元素疾病组与对照组无显著性差异。伴有高血糖、高血脂和高血压的病人,其血铬含量显著降低,表明锌、锌/铜比值、锰、钼、锶、铬元素与急性脑血  相似文献   

14.
We review concepts and provide examples for the controlled structuring of biopolymer particles in hydrodynamic flow fields. The structuring concepts are grouped by the physical mechanisms governing drop deformation and shaping: (i) capillary structuring, (ii) shear and elongational structuring and (iii) confined flow methods. Non-spherical drops can be permanently structured if a solidification process, such as gelation or glass formation in the bulk or at the interface, is superimposed to the flow field. The physical and engineering properties of these processes critically depend on an elaborate balance between capillary phenomena, rheology, gel or glass formation kinetics, and bulk heat, mass and momentum transfer in multiphase fluids. This overview is motivated by the potential of non-spherical suspension particles, in particular those formed from ‘natural’ and ‘sustainable’ biopolymers, as rheology modifiers in food materials, consumer products, cosmetics or pharmaceuticals.  相似文献   

15.
多波长线性回归法用于同时光度测定铁和铜   总被引:6,自引:2,他引:6  
赵书林  张乔 《分析化学》1993,21(1):86-89
在弱酸性介质中,在乳化剂OP存在下,铁、铜与PAN形成最大吸收均在550nm处的水溶性有色络合物,两者相互严重干扰。本文采用多波长回归分析法对此混合显色体系进行研究,选择在570~590nm区间,测定11个波长处的吸光度,使用简易程序计算器,进行数据回归处理,可简便快速地直接求出铁、铜的含量。应用于铝合金中铁、铜的同时测定,结果满意。  相似文献   

16.
通过原子吸收光谱技术对68例治疗前甲亢病人(A组),35例治疗后甲亢病人(B组),5例甲减病人(C组)及74例正常人(D组)全血多种微量元素测定分析,结果显示:D组Cu与Al,Mg与Mn正相关;Al与Zn、Se负相关;A组Fe与Zn、Ca,Ca与TT4。Cu与Mn正相关,TT与Zn、Cr负相关。B组Fe与Zn、Cu、Mg,Zn与Cu、Mn、Mg与Ca、Se、Se与TT3正相关。  相似文献   

17.
2BaC2O4 · H2O (M = 468.73) is triclinic, space group P1, with a = 9.312(1) A?, b = 9.649(1) A?, c = 6.188(1) A?, α = 90.13(2)°, β = 95.36(2)°, γ = 125.18(2)°, Z = 2, Dm = 3.48; Cx = 3.51g · cm?3. The position of the Ba atom was determined from a Patterson function. A subsequent Fourier synthesis clearly revealed the position of all C and O atoms in the structure. Refinement of the MoKα diffractometer data by a least-squares method using full matrix gave R = 0.065. The structure presents two remarkable characteristics: (a) We distinguish two types of (C2O4)2? ions. The first are planar, the second are notably separated from the plane configuration (deviation = 30°); this deformation is of a steric origin. (b) The water molecules are located in channels parallel to [001]. They enter in the coordination of one of the Ba2+ ions but do not exchange any strong hydrogen bond with oxygen atoms which surround them.  相似文献   

18.
Rearrangement of Hydrolysis Products of Tetrahydrofolate model compound   总被引:1,自引:0,他引:1  
5,6.7,8-TetrahydrofolateabbreviatedTHFisinvolvedinthebiologicaltransferofonecarbonfragmentatdifferentoxidationlevelsfformyl,formaldehyde,andmethanol.Whenthetransferablecarbonisinformicacidoxidationlevel,thehydrolysisofTHFIgives2and3respectivelyunderdifferentconditions'.(SeeSchemeI)Wehavesynthesizedl,2-dimethy-3-(p--methoxybenzeneiodide4asTHFmodelcompoundattheformicacidoxidationlevelandreporteditssubstitutedone-carbonunittransferreaction2.InordertorevealthehydrolysismechanismofTHF,thehydr…  相似文献   

19.
对临床、病理、放射线或CT检查确诊的82名癌肿患者,在放疗前后和对42名健康人进行了微量元素铁、锌、铜、锰、硒,铬、钴、镍的分析。研究结果显示:1.癌肿患者血清铜、镍、锰、铬、钴的含量比健康人高,而血清锌、铁、硒的含量却比健康人低;2.血清Cu/Zn、Cr/Zn、Co/Zn、Ni/Zn的比值癌肿患者均比健康人高,而Fe、Zn、Se/Zn的比值却相反。因此,可根据血清铜升高、血清锌降低,血清铜/锌比值升高的特点。用于癌肿的早期诊断;3.癌肿患者放疔后血清铁、锌含量进一步下降,铜、锰、铬的含量也出现降低,唯有硒的含量有所上升。因此,放疗时应注意补充铁、锌、铜元素。  相似文献   

20.
水稻耐锌程度研究   总被引:4,自引:0,他引:4  
试验于1989~1991年在江苏省农科院进行。供试水稻品种有:南京14(籼)、024—28(粳)、汕优63(杂交籼稻)、亚优2号(亚种杂文),锌肥种类有:ZnCl2、ZnSO4和ZnO。采用不同种类、不同浓度的锌肥对水稻进行盆栽试验。结果表明:(1)水稻对锌的忍耐程度极高,与不同品种内在的生物学特性有关;(2)锌肥中锌耐水稻的毒害较低,其对水稻的危害程度取决于锌肥中阴离子种类。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号