^35S标记L型胱氨酸的生物合成

一、前言~(35)S标记L型胱氨酸是研究蛋白质代谢的重要示踪剂之一。制取~(35)S记标记L型胱氨酸产品,以生物材料酵母微生物为原料,此酵母在含有无载体Na_2~(35)SO_4的培养基内培养,在通气的情况下,孵育48h。     

Preparation of 35S-Labeled Sulfite by Pyrolyzation of Copper(II) Sulfate

A study was made on the preparation of ³⁵S-labeled sulfite by the pyrolyzation of labeled Cu(II) sulfate.

Factors such as the amount of carrier sulfate and the NaOH concentration of the absorbing solutions, which were thought to affect the yield and radiochemical purity of the final products, were examined together with the chemical stability of the sodium sulfite (³⁵S) thus obtained in aqueous solutions.

The method has proved to be useful for practical preparation of ³⁵S-labeled sulfite. With Cu(II) sulfate carrier ranging 20～176 mg, more than 80% of ³⁵S can be recovered as sulfite.

Carrier-free sulfite (³⁵S) can also be obtained by merely replacing the Cu(II) sulfate carrier with Cu(II) chloride and carrier-free H₂ ³⁵SO₄.     

Chloride induced stress corrosion cracking of candidate canister materials for dry storage of spent fuel

Susceptibility to chloride induced stress corrosion cracking (ESCC) of candidate canister materials, UNS S31260 and UNS S31254 stainless steels (SS), was investigated by a constant load test in air at temperatures of 343 and 353 K with relative humidity (RH) of 35%, and at 373 K without controlling RH. UNS S31260 and UNS S31254 SS did not fail until 37,700 h at 353 K with RH = 35%, where UNS S30403 SS failed within 250–500 h. The same tendency also was obtained at 343 K, suggesting the superior ESCC resistance of UNS S31260 and UNS S31254 SS. Even rust was not observed on the specimens tested at the temperature of 373 K. To explain the higher ESCC resistance, the pitting potential was measured in the saturated synthetic sea water at temperatures from 303 to 353 K, since ESCC is usually associated with localized corrosion such as pitting and may be closely related to the corrosion resistance. The pitting potentials of UNS S31260 and UNS S31254 SS were much higher than that of UNS S30403 SS. Thus, it was concluded that the superior ESCC resistance is attributable to the higher resistance of UNS S31260 and UNS S31254 SS to pitting corrosion. The critical relative humidity for ESCC, under which no ESCC occurs, is equal to or higher than 15% at temperatures < 353 K judging from ESCC behavior of UNS S30400 SS.     

The chemical form of 35S in the coolant of CEGB nuclear reactors. Its environmental significance and determination

The radioactive isotope ³⁵S is present in the coolant of CEGB gas cooled reactors and, as a result of coolant leakage, monitored releases of ³⁵S to the atmosphere occur. Consequently, its behaviour in the environment is of importance. The critical pathway established for ³⁵S in the environment is milk contamination. The significance of the chemical form of ³⁵S and its deposition velocity on to grass in relating discharges to concentrations in milk is outlined. A gas chromatographic and associated radiochemical technique for determining the chemical form, concentration and activity of sulphur compounds in reactor coolant is described. Carbonyl sulphide (COS) was found to be the primary active form of ³⁵S in reactor coolant. This result concurs with thermodynamic calculations which show that COS would be expected to be the predominant sulphur species.     

多巴胺D2受体显像剂^125I—IBZM的合成与标记

合成了标记前体Ｓ－（－）－２－羟基－６－甲氧基－Ｎ－［（１－乙基－２－吡咯烷基）甲基］苯甲酰胺（Ｓ－（－）－ＢＺＭ）。光谱数据与结构相符。以Ｓ－（－）－ＢＺＭ为前体，用１２５Ｉ－ＮａＩ标记，成功地制备了Ｓ－（－）－３－１２５Ｉ－２－羟基－６－甲氧基－Ｎ－［（１－乙基－２－吡咯烷基）甲基］苯甲酰胺（Ｓ－１２５Ｉ－ＩＢＺＭ）。标记率大于８０％，放射化学纯度大于９０％，整个制备过程仅需４５ｍｉｎ，利于药盒化生产。     

Nuclear Data Sheets for A = 35

The experimental data are evaluated for known nuclides of mass number A=35 (Na,Mg,Al,Si,P,S,Cl,Ar,K, Ca). Detailed evaluated level properties and related information are presented, including adopted values of level and γ-ray energies, decay data (energies, intensities and placement of radiations), and other spectroscopic data. This work supersedes earlier full evaluations of A=35 published by 1990En08 (also 1998En04 update) and 1978En02.No excited states are known in ³⁵Na, ³⁵Mg, ³⁵Ca. No γ rays are known in 35K. Experimental data for ³⁵Al and ³⁵Si are limited and their radioactive decay schemes seem incomplete in view of large Q values and known excitations much below than allowed by Q values. The ³⁵S, ³⁵Cl and ³⁵Ar nuclides remain as the most extensively studied from many different reactions and decays.     

微波辐射对小鼠下丘脑超微结构影响的研究

出生15天的 C_(57)BL 小鼠接受载波频率为3GHz 的脉冲微波全身照射35天。结果表明,下丘脑线粒体对微波辐射有很高的敏感性。1mW′cm~2照射组,表现为嵴减少、模糊,少数线粒体有嵴消失及外膜破裂。5mW/cm~2照射组线粒体结构改变更明显,以嵴消失和外膜破裂为多。此外还呈现机面内质网扩张、脱粒和多核糖体减少。     

ZMS对老年大鼠脑M受体与G-蛋白偶联活性的影响

以非ＧＴＰａｓｅ水解性的［３５Ｓ］ＧＴＰγＳ在激动剂Ｃａｒｂａｃｈｏｌ作用下和Ｇ－蛋白不可逆结合,检测大鼠脑Ｍ受体与Ｇ－蛋白偶联活性,同时观察不同剂量ＺＭＳ对其活性和学习记忆的影响。结果老年组Ｇ－蛋白活性低于青年组,中、大剂量组优于老年组,并能改善学习记忆能力。Ｔａｃｒｉｎｅ无明显作用。提示老年大鼠Ｍ受体与Ｇ－蛋白偶联可能有障碍,ＺＭＳ对大鼠学习、记忆的促进作用可能与提高Ｍ受体与Ｇ－蛋白偶联活性有     

Stress corrosion cracking of stainless-steel canister for concrete cask storage of spent fuel

Resistance to external stress corrosion cracking (ESCC) and crevice corrosion were examined for various candidate canister materials in the spent fuel dry storage condition using concrete casks. A constant load ESCC test was conducted on the candidate materials in air after deposition of simulated sea salt particles on the specimen gage section. Highly corrosion resistant stainless steels (SS), S31260 and S31254, did not fail for more than 46 000 h at 353 K with relative humidity of 35%, although the normal stainless steel, S30403 SS failed within 500 h by ESCC. Crevice corrosion potentials of S31260 and S31254 SS became larger than 0.9 V (SCE) in synthetic sea water at temperatures below 298 K, while those of S30403 and S31603 SS were less than 0 V (SCE) at the same temperature range. No rust was found on S31260 and S31254 SS specimens at temperatures below 298 K in the atmospheric corrosion test, which is consistent with the temperature dependency of crevice corrosion potential. From the test result, the critical temperature of atmospheric corrosion was estimated to be 293 K for both S31260 and S31254 SS. Utilizing the ESCC test result and the critical temperature, together with the weather station data and the estimated canister wall temperature, the integrity of canister was assessed from the view point of ESCC.     

An Economic Index regarding Market Creation of Products Obtained from Utilization of Radiation and Nuclear Energy (IV)

In modern times, the use of nuclear energy and radiation are inseparable. The size of two wheels can be measured and compared by the term economic scale, which in this case refers to the revenue of electricity at terminal and production costs associated with radiation applications at a factory. The magnitude of nuclear (nuclear energy+radiation) between Japan and the United States of America (the U.S. or U.S.A.) was hereinafter compared for the year 1997. Results obtained are: (1) The economic scale of nuclear use in the U.S. was 158b$ (billion dollars), 119b$ (75%) of which was attributed to radiation applications with a further 39b$ (25%) due to nuclear energy. In the case of Japan, the total of 99b$ was composed of 52b$ (53%) radiation with a further 47b$ (47%) on nuclear energy. (2) The economic scale for nuclear use in the U.S. is larger than that of Japan by a factor of 1.6, due primarily to its larger economic scale of industry and medicine. The economic scale of nuclear energy in the U.S. is relatively smaller than that for Japan. The U.S. as opposed to Japan, which depends highly on nuclear energy, depends more highly on the use of coals for power generation. This in itself is the main reason for the smaller economic scale of nuclear energy in the U.S.