Migration characteristics of radionuclides 85+89Sr2+, 134Cs+, 125I-, 75SeO3 2- and 152+154Eu(III) in Chinese soils

The migration of radionuclides ⁸⁵⁺⁸⁹Sr²⁺, ¹³⁴Cs⁺, ¹²⁵I^- and ⁷⁵SeO₃ ^2- in calcareous soil from Yuzhong county of Gansu Province (China) at pH 7.8±0.2 and ^152+154Eu(III) in red earth from Yingtan county of Jiangxi Province (China) at pH 4.6±0.2, in presence of CaCl₂ was studied using column experiments. Results indicate that the negative anions, iodide and selenide are mobile nuclides while the migration of positive cations is related to the sorption capacity for the element. Iodide can be assumed to be non-reactive in calcareous soil. The breakthrough curves (BTCs) were fitted to the analytical solution or numerical solution of one-dimensional convection-dispersion transport models. Good agreements were obtained between the measured and predicted concentration profiles.     

拟多维高效液相色谱法分离纯化双峰驼精清中的活性蛋白

利用一种新的高效液相色谱洗脱技术，建立了 ｐＨ缓冲液／离子对二元洗脱模式，对双峰驼精清的两种提取物的反相柱上进行了分离，得到了较纯的活性蛋白组分。该法操作简单、快速、比常规ＨＰＬＣ有更高的选择性及峰容量，并可减少活性蛋白的失活。     

L—半胱氨酸与铁镍锌铅离子配位反应的热力学

L—半胱氨酸(L—Cys)是蛋白质的降解产物之一,在体内除参与蛋白质的合成外,还参与毒物的解毒过程。本文用pH电位滴定法测定L—Cys同Fe~(2+)、Ni~(2+)、Zn~(2+)、Pb~(2+)形成配合物的稳定常数,以温度系数法获得配位反应的焓变,根据所得的热力学参数,对配位反应的推动力和配合物的结构进行讨论,并进一步用红外光谱和电子光谱对Pb~(2+)、Ni~(2+)两体系所得的结果予以证实。     

Study on Arc Movement in Hollow Electrode Plasma Generators with Impressed Double Magnetic Fields

In order to prolong cathode lifetime of hollow electrode plasma generators, a method of impressed double magnetic fields with an alternating frequency is presented in this paper. The alternating frequency of the double magnetic fields is an important factor that influences the erosion rate on the area between the two coils' central planes. By analyzing the arc movement in the hollow cathode with a simplified theoretical model, the spiral curve shape of the radial arc and the relationship between the optimal alternating frequency and the intensity of magnetic fields are obtained. A photoelectric method is employed to measure the arc root rotation speed in the hollow cathode, and then the optimal alternating frequency is calculated as 319 Hz for the experimental conditions. The life testing with this alternating frequency showed that the cathode lifetime could be prolonged significantly.     

Study of the interaction of Zn^2＋ with Aβ（10-21） by fluorescamine assay

Zinc may play a role as a co-factor in the pathogenesis of Alzheimer's disease(AD)through influencing the conformation and neurotoxicity of amyloidβ-protein(Aβ).Using the fluorescamine assay,we show for the first time that Zn~(2 )induced Aβ(10-21) aggregate in a concentration-dependent manner.These results indicate that Aβ(10-21)can be used as an in vitro model in Zn~(2 )- induced Aβaggregation and that the region 10-21 to be the minimal fragment of zinc-binding domain of full length Aβ(1-42).     

Novel 99mTc labeled σ receptor ligand as a potential tumor imaging agent

A novel ^99mTc labeled complex, [N-[2-((2-oxo-2-(4-(3-phenylpropyl)piperazin-1-yl)ethyl) (2-mercaptoethyl)amino)acetyl]-2-aminoethanethiolato]Technetium(V) oxide (PPPE-MAMA’-^99mTcO) ([ ^99m Tc]-2) has been designed and prepared based on the integrated approach. The corresponding rhenium complex (PPPE-MAMA’-ReO)(Re-2) has been prepared and characterized. In vitro competition binding assays show moderate affinity of Re-2 towards σ₁ and σ₂ receptors with K _i values of 8.67 ± 0.07 and 5.71 ± 1.88 μmol, respectively. Planar images obtained at 0.5 h, 4 h, 20 h after i.v. injection indicate the accumulation of [ ^99m Tc]-2 in MCF-7 human breast tumor bearing mice at 20 h. Furthermore, the accumulation of [ ^99m Tc]-2 has been inhibited at 20 h after co-injection of [ ^99m Tc]-2 plus haloperidol (1 mg/kg). Biodistribution studies of [ ^99m Tc]-2 display an in vivo tumor uptake of 0.14% ± 0.01% ID/g at 24 h post i.v. injection with a tumor/muscle ratio of 6.02 ± 0.87. The above results suggest that [ ^99m Tc]-2, derived from a previously published lead compound, retains certain tumor uptake and affinity for σ receptors. [ ^99m Tc]-2 may be used as a basis for further structural modifications to develop tumor imaging agents with high affinity for σ receptors.     

Phase relationships in the system Y2O3-ZrO2

Russian Chemical Bulletin -     

Sigma-aromaticity and sigma-antiaromaticity in saturated inorganic rings

The magnetic properties of a series of inorganic saturated rings, (SiH2)n, (GeH2)n, (NH)n, (PH)n, (AsH)n, On, Sn, and Sen (n = 3-6), exhibit zigzag behavior with ring size resembling that of aromatic and antiaromatic Hückel pi-systems and (CH2)n rings. Computed GIAO-SCF nucleus-independent chemical shifts (NICS) and localized (LMO) NICS analysis indicate that the sigma-ring electrons are chiefly responsible for this zigzag behavior. This evidence for sigma-aromaticity is further supported by theoretical strain energy (TSE). The Hückel 4n + 2/4n aromaticity/antiaromaticity rule for pi-electron systems applies well to the smaller saturated rings.     

通过密度函数理论表征炭质吸附剂的孔径分布

通过密度函数理论（DFT-DensityFunctionalTheory）对炭质吸附剂的孔径分布进行了表征。该法以多孔固体上N2吸附分子模型为依据，用一种方法对多孔固体的孔径分布从微孔到大孔范围进行确定。本文用该法对自制的聚丙烯腈活性炭纤维、国产煤质活性炭及日本产活性炭微球等六种炭质吸附剂的孔径分布进行了表征。