Radiopharmaceuticals in nuclear medicine diagnostic procedures and the problem of radiation protection

Taken into account the extremely high radiotoxicity of DNA-bound Auger emitters the values of absorbed and equivalent dose for various radionuclides commonly used in nuclear medicine diagnostic procedures were reevaluated. The results show that the equivalent dose is highly depend on the fraction of activity bound to the DNA, illustrating the importance of subcellular distribution of Auger electron emitters in assessing the equivalent dose.     

TNO Institute of Environmental Sciences, Energy Research and Process Innovation, the Netherlands

Abstract— A radiative transfer model is used to study the effect of stratospheric ozone depletion and tropospheric pollution on UVB (280-315 nm) radiation in the troposphere at midiatitudes of the Northern Hemisphere. The difference in the vertical distribution of UVB radiation for a range of pollution conditions typical for remote clean and more polluted sites on cloudless summer days is shown. The changes in downward UVB irradiance, UVB actinic flux, DNA-weighted UV radiation and photodissociation frequency of ozone at the earth's surface are quantified in relation to stratospheric ozone depletion and typical ranges of tropospheric pollutants (ozone [O3], sulfur dioxide [SO₂] and aerosols) in nonurban polluted regions. The results show that near the earth's surface, in non-urban polluted regions, an increase of tropospheric pollution, which occurred over the last 50-100 years, has cancelled the effect of an increase of UVB radiation due to stratospheric ozone depletion that has occurred since the late 1970s. The results hold for summer conditions and the decrease of UVB radiation is most pronounced in the polluted boundary layer. At higher altitudes the effect of tropospheric pollution on UVB radiation is far less. Prior to 1970 it was mainly tropospheric pollution that altered UVB radiation at the surface of the earth. In addition, since the late 1970s enhanced UVB radiation reaching the top of the troposphere, due to stratospheric ozone depletion, also had an impact on UVB levels in the troposphere.     

Hemodynamics and Wall Shear Stress of Blood Vessels in Aortic Coarctation with Computational Fluid Dynamics Simulation

The purpose of this study was to identify the characteristics of blood flow in aortic coarctation based on stenotic shape structure, stenosis rate, and the distribution of the wall load delivered into the blood vessels and to predict the impact on aneurysm formation and rupture of blood vessels by using a computational fluid dynamics modeling method. It was applied on the blood flow in abdominal aortic blood vessels in which stenosis occurred by using the commercial finite element software ADINA on fluid-solid interactions. The results of modeling, with an increasing stenosis rate and Reynolds number, showed the pressure drop was increased and the velocity was greatly changed. When the stenosis rate was the same, the pressure drop and the velocity change were larger in the stenosis with a symmetric structure than in the stenosis with an asymmetric one. Maximal changes in wall shear stress were observed in the area before stenosis and minimal changes were shown in stenosis areas. The minimal shear stress occurred at different locations depending on the stenosis shape models. With an increasing stenosis rate and Reynolds number, the maximal wall shear stress was increased and the minimal wall shear stress was decreased. Through such studies, it is thought that the characteristics of blood flow in the abdominal aorta where a stenosis is formed will be helpful in understanding the mechanism of growth of atherosclerosis and the occurrence and rupture of the abdominal aortic flow.     

铝氟联合中毒大鼠骨、脑、血、尿中多元素含量动态检测

同批断乳两周的Wistar雄性大鼠59只,随机分为3个组,用同一病家的高岭土拌煤烘干与柴烘玉米加入配合饲料喂养.饲料含氟、铝3.9×10-6,12.4×10-6;107×10-6,40.4×10-6;212,66.8×10-6.实验11、20周分两批股动脉放血处死.检测了大鼠骨、脑、血、尿中多种元素.结果表明,血清钙一直较高,磷降低.实验11周,Ⅱ、Ⅲ组骨氟分别增高6、10倍,尿氟增高4、6倍;骨、脑、全血铝均随摄氟、铝量的增多而递减,尿铝递增.尿中其它元素多一直减少.骨中金属元素随骨铝的递减而递减.Ⅱ组全血锌显著下降.实验20周,Ⅱ、Ⅲ组骨氟是Ⅰ组的3.5和8.2倍,为实验11周时的58.1%和80.7%;尿氟是1.4和3倍.骨、脑铝随氟、铝摄入量的递增而递增,骨中金属元素含量也随之递增,骨磷降低.全血磷递增,锌均升高.本实验多元素含量由低向高变化的逆反过程与骨软化向硬化的病理转换相吻合;铝和氟彼此可影响对方的体内过程和在骨骼中的蓄积并引起多元素含量和相关性的显著变化.提示消化道内源性无机盐排泄过多;低龄动物的骨、脑对铝有排斥反应,但有铝危害表现.     

Quality system implementation in the National Metrology Institute of Montenegro

Accreditation and Quality Assurance - Accreditation of calibration laboratories is a means for achieving competence recognition and assuring customers that their calibration services are accurate...     

Building unit and topological evolution in the hydrothermal DABCO-U-F system

Compounds NDUF-1 ([C(6)H(14)N(2)](UO(2))(2)F(6); P2(1)/c, a = 6.9797(15) A, b = 8.3767(15) A, c = 23.760(5) A, beta = 91.068(4) degrees, V = 1388.9(5) A(3), Z = 4), NDUF-2 ([C(6)H(14)N(2)](2)(UO(2))(2)F(5)UF(7).H(2)O), NDUF-3 ((NH(4))(7)U(6)F(31); R3, a = 15.4106(8) A, c = 10.8142(8) A, V = 2224.1(2) A(3), Z = 3), and NDUF-4 ([NH(4)]U(3)F(13)) have been synthesized hydrothermally from fixed composition reactant mixtures over variable time periods [DABCO (C(6)H(12)N(2)), UO(2)(NO(3))(2).6H(2)O, HF, and H(2)O; 2-14 days]. Observed is a systematic evolution of the structural building units within these materials from the UO(2)F(5) pentagonal bipyramid in NDUF-1 and -2 to the UF(8) trigonal prism in NDUF-2 and finally to the UF(9) polyhedron in NDUF-3 and -4 as a function of reaction time. Coupled to this coordination change is a reduction of U(VI) to U(IV) as well as a breakdown of the organic structure-directing agent from DABCO to NH(4)(+). These processes contribute to a structural transition from layered topologies (NDUF-1) to chain (NDUF-2), back to layered (NDUF-3), and ultimately to framework (NDUF-4) connectivities. The synthesis conditions, crystal structures, and possible transformation mechanisms within this system are presented.     

胎儿脐带血铅水平与钙、锌、铁的关系研究

目的研究胎儿脐带血中的铅与钙、锌、铁的含量以及两两之间的相关性。方法采用原子吸收光谱法对398例脐带血铅和钙、锌、铁的含量进行测定,并对它们进行相关性分析。结果 398例脐带血铅和钙、锌、铁的质量浓度分别为铅(37.96±17.78)μg/L、钙(1.51±0.29)mmol/L、锌(30.01±11.14)μmol/L、铁(8.63±1.39)mmol/L。线性回归分析显示:铅与钙(r=-0.563,P0.01)、铅与锌(r=-0.424,P0.01)有相关性,铅与铁无显著相关(r=0.018,P0.05)。结论随着胎儿体内血铅水平的上升,二价元素钙、锌含量有下降趋势,即中毒元素铅会干扰胎儿体内的必需二价元素的代谢。     

The effect of chronic ultraviolet radiation on the human immune system

A single or a limited number of UVR exposures is recognized to suppress cell-mediated immunity in human subjects. The complex pathway leading from the absorption of photons by chromophores in the skin to the generation of T regulatory cells has been, at least partially, elucidated. However, the effect of repeated UV exposures on immune responses and associated mediators is not well studied, particularly to assess whether they lead, first, to the development of photoprotection so that these immune changes are reduced or no longer occur, and, secondly, to the development of photoprotection against the normal downregulation of immunity induced by a high UV dose. For almost all the parameters evaluated in this review--epidermal DNA damage/erythema, urocanic acid, Langerhans and dendritic cells, natural killer cells, macrophages, mast cells, contact and delayed hypersensitivity responses--none, aside from epidermal DNA damage/erythema and macrophage phagocytic activity, show convincing evidence of photoadaptation or, where appropriate, photoprotection. It is concluded that repeatedly irradiating individuals with UVR is likely to continue to result in downregulation of immunity.     

The Use of Automated Headspace Gas Chromatography for Determination of 1,1,1-Trichloroethane in Rat Blood and Brain Tissue

Abstract

1,1,1-trichloroethane in blood and brain tissue from rats which had been artificially ventilated with solvent (8000 ppm) was analysed by automated headspace gas chromatography using a fused silica capillary column. A given concentration of 1,1,1-trichloroethane in the brain could be correlated with a corresponding concentration in the blood; both the uptake and release of the solvent were quicker in blood than in brain. No volatile metabolites of the solvent were found. Automated headspace gas chromatographic analysis is a rapid and sensitive technique for the quantitative registration of volatile organic solvents, e.g. of industrial importance, in body fluids and tissues.     

Preparation of some derivatives of 3-mercaptopropionic acid,cystamine, and cysteamine and study of their radiation protection properties

Conclusions A number of new derivatives of 3-mercaptopropionic acid, cystamine, and cysteamine were synthesized, and their radiation protection properties were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 334–341, February, 1967.     

The development and use of food reference materials at the Philippine Food and Nutrition Research Institute

Summary As the Philippine government's main investigator and compiler of local food composition data, the FNRI has been conducting activities on food reference materials since 1987, in accordance with guidelines of the 1983 UNUINFOODS and 1986 ASEANFOODS initiatives. Results of these activities as well as problems encountered therein are summarized. Similar activities of the Asia-Pacific Food Analysis Network (APFAN) are also reported. These activities demonstrate the attempts to harmonize analytical methods in laboratories of the Asia-Pacific region.     

抗日战争时期的中央研究院化学研究所

考查了抗战时期中央研究院化学所的内迁经过以及在大后方恢复重建、开展科学研究的艰难历程,并对化学所战时科研的特点及学术贡献等相关问题进行详细探讨。