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171.
Z H Liu W S Tu D R Li Y D Li C H Xie Y Z Yang B B Qin 《Biomedical chromatography : BMC》1990,4(2):83-86
A high performance liquid chromatographic (HPLC) method for the analysis of aflatoxin M1 (AFM1) in urine is described. Urine samples were treated with saturated lead acetate and AFM1 was extracted with chloroform. After washing with water to remove impurities the compound was derivatized with trifluoroacetic acid and the AFM1 derivative was analyzed quantitatively by HPLC. The sample pretreatment is simple and more selective. A good line correlation between AFM1 peak height and its concentration was obtained when AFM1 content was in the range of 50-400 pg. The ratio of recovery was 87.42%. Sensitivity is 0.01 ppb. The method is applicable to trace analysis. Results in urine of residents who live in the high/low liver cancer incidence area in Fushui county were the same as that of previous epidemiological investigation. 相似文献
172.
173.
Ge-132对小鼠H22肝癌移植瘤的实验研究证明:1.Ge-132对H22肝癌移植瘤有一定的抑制作用,300mg/kg体重剂量抑瘤率达到36.19%;2.增强机体的抗氧化作用,抑制脂质的过氧化物水平;3.促进免疫功能,当Ge-132和环磷酰胺联合使用时,可抵抗环磷酰胺的免疫抑制作用,而且并不减弱其抑制瘤作用。 相似文献
174.
Zhang WW Ren XM Li H Xie JL Lu CS Zou Y Ni ZP Meng QJ 《Journal of colloid and interface science》2003,268(1):173-180
Self-assembled monolayers (SAMs) of functionalized azobenzene thiols (RAzoCnSH, n=3-6 for R=H, abbreviated as AzoCnSH; and n=4 for R=CH(3)CONH, abbreviated as aaAzoC4SH) on different substrates RAzoCnSz.sbnd;z.sfnc;S (S represents substrates of vacuum-deposited gold (Au), silver foil (Ag), HNO(3) etched silver foil (EAg), and silver mirror (mAg)) have been studied by SERS in the near-infrared region. SERS of the SAMs on EAg and/or mAg exhibit SERS effects that vary with etching time and/or deposition time. The most appropriate time is 5 s for etching in 1:1 HNO(3) and 40 s for deposition in 0.1 M Ag(NH(3))(2)NO(3). Further, a layer of Ag mirror was conveniently deposited on the top of the SAMs on different substrates, yielding a more efficient SERS-active system possessing a "sandwiched" structure of mAgz.sfnc;RAzoCnS-z.sfnc;S. An appropriate surface roughness is required for the strongest SERS effect. Scanning electron microscopy (SEM) indicates that there exist a large number of projects around 100 nm on the surface showing the strongest SERS effect. When the surface roughness is decreased or increased, the SERS effect decreases sharply. The relationship between the SERS effect and the structural nature was investigated and showed that the enhancement factor decays exponentially with increasing in distances of the azobenzene group from the underlying substrate or the overlying silver mirror. This result reveals that the SERS effect may be the result of the electromagnetic coupling effect between two metal layers. 相似文献
175.
Ammonia-treated activated carbon has been studied as a support of Ru-Ba catalyst for ammonia synthesis. It is shown that the
introduction of nitrogen leads to a decrease of ammonia synthesis activity for the catalysts with a low Ba/Ru molar ratio,
while no significant changes are obtained for the catalysts with a high Ba/Ru molar ratio, confirming that electronegative
impurities suppress the activity in ammonia synthesis and consume part of the promoters.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
176.
177.
178.
A new hydroxo‐bridged dimeric Cr(III) complex [Cr(saltn)OH]2·4H2O [H2saltn=N,N′‐bis(salicylidene)trimethylenediamine] has been synthesized and its structural and magnetic properties have been investigated. The complex crystallizes in the triclinic space group P‐1 with one dimeric formula unit in a cell of dimensions a=0.95828(19) nm, b=0.95926(19) nm, c=1.0437(2) nm, α=86.77(3)°, β=82.48(3)°, and γ=64.93(3)°. The geometry around each chromium(III) center is six‐coordinate, distorted‐octahedral. The bridging Cr2O2 unit is strictly planar, as required by the crystallographic symmetry. The Cr? O? Cr′ bridging angle is 99.94(16)°, and the distance between Cr…Cr′ is 0.3019 nm. The magnetic susceptibility of the complex has been examined in the range of 2‐300 K. By using the spin‐spin coupled model for an S1=S2=3/2 dimeric system , the magnetic data were fitted to give the parameters of g=2.01(1), J=‐0.85(2) cm‐1, and zJ' =0.18(3)cm‐1, indicating the presence of a weak antiferromagnetic spin‐exchange interaction between the Cr(III) ions in the binuclear complex. 相似文献
179.
加氢脱氮催化剂中硫化钼结构的表征 总被引:1,自引:0,他引:1
众所周知,重油加氢脱氮(HDN)所用Mo-Ni/Al2O3催化剂需经预硫化后始有显著的活性,关于硫化的条件工业上已较成熟,但在持续反应过程中硫化催化剂的结构与活性间的关系则很复杂,如硫化钼的价态和结构、金属组分和担体间的相互作用、反应条件及原料对催化剂组分的影响,以及硫化态催化剂中MoS2结晶的形貌等都可以引起催化剂活性本质的变化. 相似文献
180.
Mao Jiang-Gao Huang Jin-Shun Ma Jian-Fang Ni Jia-Zuan 《Transition Metal Chemistry》1997,22(3):277-280
The reaction of diglycolic acid, O(CH2CO2H)2, with Cu(NO3)2·2H2O and lanthanoid nitrate hydrate produces a series of novel Ln–Cu mixed metal complexes, [Ln2Cu3{O(CH2CO2)2}6]·nH2O (Ln=La, Nd, n=9; Ln=Er, n=6), which have been characterized by elemental analysis, i.r. spectroscopy, magnetic measurements and X-ray crystallography. The Ln3+ and Cu2+ ions are connected by the carboxylate groups of the ligands, resulting in the formation of a complicated network. 相似文献