兔肝金属硫蛋白稀水溶液的脉冲辐解

金属硫蛋白(Metallothioneins,简称MTs)是一类富含巯基和金属的低分子量蛋白质,广泛存在于哺乳动物中.MTs 通常含61个氨基酸,其中20个为半胱氨酸,不含芳香族氯基酸和组氨酸,因此在280nm 附近没有吸收峰.MTs 通常结合7个Cd 或zn,20个巯基全部去质子化并参与配位,从而形成牢固的结构域.有证据表明MTs 可能有储存Zn 和Cu 的作用,同时能减轻重金属对动物细胞的毒性,但其生理功能一直不很清楚.近几年的研究表明,MTs 能增强机体对电离辐射的耐受力、修复DNA 损伤,这可能与MTs 中含有丰富的巯基有关.体外实验测得k_(MT/OH)=10~(12)dm~3·mol~(-1)·s~(-1),k_(MT/O(?))=5×10~5dm~3·mol~(-1)·s~(-1),但其辐解机理尚不清楚.本工作利用脉冲辐解技术研究了免肝MT-I 稀水溶液辐解时的中间过程,并作了初步的解释.     

Molecular structure and spectral properties of thionaphthalimides

The molecular structure and absorption spectra of monothio- and dithio-naphthalimides were compared to their naphthalimide analogues using AM1, PM3 and ZINDO/S semiempirical quantum chemical methods. The substitution of the 4R-naphthalimide oxygen atoms by sulphur atoms resulted in a red-shift of the absorption spectra by Δλ_max60-65 and 100-140 nm, respectively. The thionated naphthalimide derivatives do not show observable fluorescence due to intersystem crossing to the triplet -states localised at the CS groups. The -absorption bands of monothioimides are located at 525-580 nm (ε=60-80) and those for dithioimides at 535-560 nm (ε=140-390) and 628-686 nm (ε=34-68). None of these transitions are solvent sensitive. The -transitions of N-phenylthioimides have also a small contribution from -states due to a partial conjugation between CS group and π-electronic system of the N-phenyl ring. As a result, the bands of aromatic substituted N-phenylthioimides are red-shifted as compared to those of the aliphatic N-methyl-thioimides.     

One-electron oxidation of toluidine blue. A pulse radiolysis study

The one-electron oxidation of toluidine blue by specific oxidising radicals such as Cl ₂ ⁻ , Tl(II), N₃, Br ₂ ⁻ etc. has been studied by employing the pulse radiolysis technique. The Br ₂ ⁻ radical was found to be less efficient in oxidising toluidine blue as compared to Cl ₂ ⁻ ., Tl⁺² and N₃. The semioxidised species exhibited only onepK _a indicating the presence of two conjugate acid-base forms whose spectral and kinetic features were evaluated. Reaction of OH radicals with the dye gave rise to a transient species which exhibited spectral and kinetic features different from that of the semioxidised species indicating that the mode of reaction of OH is different.     

电爆炸箔断路开关的理论和实验研究

 采用金属箔电爆炸过程的二维数值计算模型，对含电爆炸金属箔断路开关的电感储能脉冲功率调节系统进行了数值计算。以此为基础，研制出了一种低电感型的电爆炸箔断路开关，并以4μF/75kV脉冲电容器组作为初级能源，13Ω电阻作为负载进行实验研究。研究结果表明：在负载上可获得约250kV，脉宽大于400ns的脉冲电压。     

S-5N全固态重复频率脉冲发生器

 主要介绍S-5N的结构及测试实验结果。S-5N型全固态重复频率脉冲发生器是目前国际上同类源中峰值功率和平均功率均为最大的一台。随负载大小的变化，S-5N脉冲发生器的输出电压为400～600kV，输出电流2～3kA，输出脉冲半高宽40～50ns，单脉冲输出能量40～65J。 S-5N脉冲发生器在300Hz重复频率条件下可连续工作，500Hz重复频率条件下可连续工作3min，平均输出功率高达30kW。     

Accurate mass determination,quantification and determination of detection limits in liquid chromatography–high-resolution time-of-flight mass spectrometry: Challenges and practical solutions

Uniform guidelines for the data processing and validation of qualitative and quantitative multi-residue analysis using full-spectrum high-resolution mass spectrometry are scarce.     

Ideal optomechanically induced transparency generation in a cavity optoelectromechanical system

The ideal optomechanically induced transparency effects of an output probe field are investigated in a cavity optoelectromechanical system, which is composed of an optical cavity, a charged mechanical resonator, and a charged object.Although the charged mechanical resonator damping rate is nonzero, the ideal optomechanically induced transparency can still appear due to the non-rotating wave approximation effect in the system. The location of optomechanically induced transparency dip can be controlled via the Coulomb coupling strength. In addition, we find that both the transparency window width and the maximum dispersion curve slope are closely related to the optical cavity decay rate.     

红细胞分布宽度与心房颤动负荷的关系研究

目的观察病态窦房结综合征患者心房颤动负荷与红细胞分布宽度（RDW）的关系。方法选择病态窦房结综合征植入永久性人工心脏起搏器的患者81例，回顾性分析患者入院时基本资料、血常规及生化指标。记录术后3个月起搏器记录的心房颤动负荷。根据患者心房颤动负荷分为高负荷组及低负荷组，比较分析两组患者RDW及相关临床资料。结果心房颤动高负荷组患者RDW（15.61±1.23）%，高血压比例71%，明显高于低负荷组的（13.50±1.03）%、46%（P＜0.01或0.05）。高负荷组左心房直径、左心室舒张末期内径、WBC、TG、TC均大于低负荷组（P＜0.01或0.05）。心房颤动负荷影响因素的logistic回归分析显示，RDW是心房颤动负荷高的预测因素（OR=10.32，P＜0.01）。高TG、高血压、高胆固醇也是心房颤动高发的预测因素。结论心房颤动负荷除与年龄，高血压有关外，还与RDW明显相关。RDW可成为病态窦房结综合征患者心房颤动负荷的预测因素之一。     

Radiolysis of 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-porphyrin or 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin in aqueous solution in the presence and in the absence of DNA or human serum albumin

The reduction of two free-base ionic porphyrins: 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-porphyrin (TMPyP) and 5,10,15,20-tetrakis(4-sulfonatophenyl)-porphyrin (TSPP) by the hydrated electron was studied under neutral pH in aqueous solution in the absence and in the presence of biomolecules, DNA or HSA. Pulse radiolysis studies provided the spectra of the short-lived π-radical anions and steady-state radiolysis led to formation of stable phlorin or chlorin, the products of two-electron reduction and protonation at a meso and a pyrrolic nitrogen positions or at two β-pyrrole positions, respectively. Identification of the final reduction products was based on their reactivity to molecular oxygen—the phlorin, contrary to chlorine, was oxidized rapidly by O₂ to recover the original porphyrin. The stable product of TMPyP reduction was the phlorin, whereas for TSPP the chlorine and the phlorin were obtained. Addition of biomolecules to the solution resulted in changes of the porphyrins spectroscopic properties and in the decrease in rates of the occurring reduction processes proceeding with participation of the porphyrins.     

深水多波束测深系统脉冲压缩实时算法

线性调频信号是大时宽带宽积信号,通过脉冲压缩可提高探测距离和分辨率,已在深水多波束测深系统中得到广泛应用。针对深水多波束测深系统中脉冲压缩运算量大的问题,提出了一种基于分组的脉冲压缩实时算法。该算法对需要进行脉冲压缩的波束进行分组,每个节拍只计算一组波束,可大幅减少深水多波束测深系统脉冲压缩的运算时间,节省了处理器资源。该算法已成功应用于某深水多波束测深系统,经多次海试证明,工作稳定可靠。