炉甘石中ZnCO_3,ZnO,PbCO_3,Fe_2O_3,(CaCO_3+MgCO_3)含量测定的研究

（１）以氨水（１＋４）溶解样品，用ＸＯ作指示剂，ＥＤＴＡ滴定，测定ＺｎＣＯ３含量。（２）以１５％的硫酸铵溶解样品，用ＸＯ作指示剂，ＥＤＴＡ滴定，测定（ＺｎＣＯ３＋ＺｎＯ）含量。（３）以１５％的氯化铵溶液溶解样品，用ＥＢＴ作指示剂，ＥＤＴＡ滴定，测定（ＺｎＣＯ３＋ＺｎＯ＋ＣａＣＯ３＋ＭｇＣＯ３）含量。（４）以１６％的乙酸铵溶液溶解样品，以ＸＯ作指示剂，ＥＤＴＡ滴定，测定（ＰｂＣＯ３＋ＺｎＣＯ３＋ＺｎＯ）含量。（５）以稀盐酸溶解样品，用磺基水杨酸作指示剂，ＥＤＴＡ滴定，测定Ｆｅ２Ｏ３含量。     

Subcostal, 3-4 cm, mini-cholecystectomy. A 3-year follow-up

The authors report the results of mini-cholecystectomy performed through a 3 to 4 cm long subcostal incision in 29 patients with the diagnosis of acute or chronic cholecystitis, from February 1991 to November 1922. Some of the patients were obese, diabetics or presented as emergency cases. The patients were operated on in the morning, as in laparoscopic cholecystectomy, began oral intake in the afternoon and were discharged on the day after surgery. Dissection of the gallbladder was facilitated by the use of a modified gynecologic valve and long thin instruments. Duration of surgery varied from 40 to 140 minutes. Patients could return to work on the third day after surgery. Notably, the costs/benefits were on the third more favorable than those of laparoscopic cholecystectomy.     

Cases 1, 2, and 3

A quantitative analysis of amino acids in microsamples of dried blood spots by chemical ionization mass spectrometry has been developed. Isotope ratio determination was used as the quantitating technique via multiple labelled internal standards. This procedure yields excellent precision and accuracy as demonstrated by the analysis of known amino acid mixtures and of phenylalanine in the blood from newborns.     

The mechanical behavior of nonstoichiometric compounds Ni3Si,Ni3Ge,and Fe3Ga

The compression flow stress of the three kinds of nonstoichiometric Ll₂ compounds has been measured as a function of composition in the temperature range from 77 to 800 K. The effect of nonstoichiometry on the positive temperature dependence of strength and the defect strengthening in polycrystalline Ni₃Si, Ni₃Ge, and Fe₃Ga alloys are quite similar to those found previously in Ni₃Al and Ni₃Ga alloys. However, the more intensive positive temperature dependence of strength, the limited homogeneity range within the nickel-rich side of stoichiometry and the lattice contraction in forming Ll₂ ordered structure observed in Ni₃Si and Ni₃Ge are concluded to be characteristic nature of compounds containing 4B-subgroup elements as the minority component. The difference of the extent of homogeneity range in various Ll₂ compounds is explained by an asymmetric index deduced from the consideration of the shape of free energy curve in the vicinity of stoichiometry. All these characteristic natures are discussed in terms of the change in bond strength.     

Enzymatic properties of the unnatural beta-L-enantiomers of 2',3'-dideoxyadenosine and 2',3'-didehydro-2',3'-dideoxyadenosine

The beta-L-enantiomers of 2',3'-dideoxyadenosine and 2',3'-didehydro-2',3'-dideoxyadenosine have been stereospecifically synthesized. In an attempt to explain the previously reported antiviral activities of these compounds, their enzymatic properties were studied with respect to adenosine kinase, deoxycytidine kinase, adenosine deaminase, and purine nucleoside phosphorylase. Adenosine deaminase was strictly enantioselective and favored beta-D-ddA and beta-D-d4A, whereas adenosine kinase and purine nucleoside phosphorylase had no apparent substrate properties for the D- or L-enantiomers of beta-ddA or beta-d4A. Human deoxycytidine kinase showed a remarkable inversion of the expected enantioselectivity, with beta-L-ddA and beta-L-d4A having better substrate efficiencies than their corresponding beta-D-enantiomers. Our results demonstrate the potential of beta-L-adenosine analogues as antiviral agents and suggest that deoxycytidine kinase has a strategic importance in their cellular activation.     

Synthesis of Hexp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Manp-(1-->O) (CH2)7 CH3 probes for exploration of the substrate specificity of glycosyltransferases: Part II, Hex = 3-O-methyl-beta-D-Gal, 3-deoxy-beta-D-Gal, 3-deoxy-3-fluoro-beta-D-Gal, 3-amino-3-deoxy-beta-D-Gal, beta-D-Gul, alpha-L-Alt, or beta-L-Gal

Seven analogues of the trisaccharide beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Manp-(1-->O)(CH 2)7CH3 have been synthesized as potential substrates for glycosyltransferases involved in the chain-termination of N-acetyllactosamine-type N-glycans. These compounds include: 3-O-methyl-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Manp -(1-->O) (CH2)7CH3, 3-deoxy-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Manp-(1 -->O) (CH2)7CH3, 3-deoxy-3-fluoro-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-M anp- (1-->O)(CH2)7Ch3, 3-amino-3-deoxy-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Ma np- (1-->O)(CH2)7CH3, beta-D-Gulp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Manp-(1-- >O)(CH2)7CH3, beta-L-Galp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Manp-(1-->O)(CH 2)7CH3, and alpha-L-Altp-(1-->4)-beta-D-GlcpNAc-(1-->2)-alpha-D-Manp-(1- ->O) (CH2)7CH3. All trisaccharides were obtained by condensation of suitably modified glycosyl donors based on imidates or thioglycosides with the same disaccharide acceptor, octyl 3,4,6-tri-O-benzyl-2-O-(3,6-di-O-benzyl-2-deoxy-2-phthalimido-beta-D- glucopyranosyl)-alpha-D-mannopyranoside, followed by deprotection.     

Neuromuscular blocking N,N'-polymethylene bistropanium, bis 3alpha-hydroxytropanium and bis 3-oxotropanium compounds

To explore the role of ester groups in the neuromuscular blocking (NMB) property of various quaternary ammonium tropinesters, we have synthesized and pharmacologically evaluated twenty bisquaternary ammonium derivatives where two tropane (I), 3alpha-hydroxytropane (II), or 3-oxotropane (III) moieties were connected on their nitrogen atoms with a polymethylene chain of C3-C12 length. The rank order of potency of these agents in the rat (evoked EMG responses of the ant. tibial muscle) was: I, II, and III. Most potent were the longer chain (e.g. C10-C12) compounds of series I, yet they were inferior to bisquaternary ammonium tropinester derivatives (e.g. N,N'-polymethylene bisquaternary tropinesters, or bisquaternary derivatives of dicarboxylic acid tropinesters). Although some of the agents (series I and II) showed a rapid onset and short duration of action-profile, they also exhibited cardiovascular side effects (e.g. cardiac vagal block and blood pressure changes). In the design of new NMB agents of rapid onset and short duration of action the presence of different ester groups in addition to an azabicyclo ring system (e.g. tropane), seems to be essential.     

X射线荧光光谱法测定Dy_2O_3及其杂质Eu_2O_3,Gd_2O_3,Tb_4O_7,Ho_2O_3,Er_2O_3和Y_2O_3

当前稀土应用范围越来越广,尤其Dy2O3和金属Dy其出口量不断增大．Dy2O3中所含杂质总量通常在0．1％～5％之间,该范围内的测定方法以XRFR为合适,快速、准确、无破坏．1实验部分1．l原理本法采用粉末直接压片法制样,在各元素分析线峰位上测量X射线强度,根据待测元素的X射线荧光光谱强度与含量的定量关系,选择相应的数学模型,由计算机自动计算出待测成份含量．1．2仪器和试剂荷兰飞利浦PW—1400顺序式X射线荧光光谱仪;康柏486计算机;电动小型油压机;万分之一精度分析天平．DyZO399．999％;EnD3,GdD3,ThAn,HoAn,ErD3…     

两步法制备钛酸钡、钛酸锶和钛酸锶钡纳米管阵列

通过常温恒压条件下在1%HF溶液中对钛进行阳极氧化,形成大面积管径10~100nm、长度100~700nm的氧化钛纳米管阵列,考察了恒压条件下氧化电流随时间的变化曲线。然后以此氧化钛纳米管阵列为膜板,分别在0.1mol.L-1氢氧化钡、氢氧化锶或氢氧化锶和氢氧化钡混合溶液中进行水热反应,形成钛酸钡、钛酸锶和钛酸锶钡纳米管状阵列,根据使用的膜板不同其管径在10~90nm,长度100~700nm范围内可调,这种铁电纳米管结构排列整齐,在微电子、光电子和生物陶瓷等领域具有很多潜在的应用前景。