Pharmacological studies of dopamine transporter imaging agent 125／131I－β－CIT

To prepare ^125/131I-β-CIT(2β-carbomethoxy-3β-(4-iodophenyl)tropane) as an imaging agent for dopamine transporter (DAT),the labeling method from tributylstannyl precursor with peracetic acid has been reported in this article.The radiochemical purity(RCP) of the labeled compound was over 95% determined by HPLC and TLC.The stability,partition coefficients were also determined.The pharmacological studies of the imaging agent were performed in rats,mice,rabbits and normal monkey.The ligand showed preferable uptake in rats,mice,rabbits and normal monkey.The ligand showed preferable uptake in brain (1.9%ID/organ in rats and 4.5%ID/organ in mice at 5min).The ratios of striatum/cerebellum,hippocampus/cerebellum and cortex/cerebellum were 29.8,3.97and 4.75 at 6h in rats,and 8.52,2.99 and 3.06 at 6h in mice,respectively.In monkey brain imaging the ratios of striatum/frontal cortex(ST/FC)and striatum/occipital cortex(ST/OC) were 5.14 and 5.97 at 4h.respectively,All of above showed the high affinity of the ligand to DAT,The compound was primarily metabolized in liver because the hepatic uptake was much higher than other organs(75.4%ID/organ at 18h).The half-life of blood elimination was 5min.The dose received by mice was 2500 times as high as that received by human in the test of undue toxicity,which evaluated the safety of the agent.All the results suggest that β-CIT can be used as a potential DAT imaging agent.     

Nondestructive Determination of Cu Residue in Orange Peel by Laser Induced Breakdown Spectroscopy

Laser induced breakdown spectroscopy(LIBS) is an emerging tool with rapid,nondestructive,green characteristics in qualitative or quantitative analyses of composition in materials.But LIBS has its shortcomings in detect limit and sensitivity.In this work,heavy metal Cu in Gannan Navel Orange,which is one of famous fruits from Jiangxi of China,was analyzed.In view of LIBS's limit,it is difficult to determinate heavy metals in natural fruits.In this work,nine orange samples were pretreated in 50-500 μg/mL Cu solution,respectively.Another one orange sample was chosen as a control group without any pollution treatment.Previous researchers observed that the content of heavy metals is much higher in peel than in pulp.So,the content in pulp can be reflected by detecting peel.The real concentrations of Cu in peels were acquired by atomic absorption spectrophotometer(AAS).A calibration model of Cu I 324.7 and Cu Ⅰ 327.4was constructed between LIBS intensity and AAS concentration by six samples.The correlation coefficient of the two models is also 0.95.All of the samples were used to verify the accuracy of the model.The results show that the relative error(RE) between predicted and real concentration is less than 6.5%,and Cu Ⅰ 324.7 line has smaller RE than Cu Ⅰ 327.4.The analysis demonstrated that different characteristic lines decided different accuracy.The results prove the feasibility of detecting heavy metals in fruits by LIBS.But the results are limited in treated samples.The next work will focus on direct analysis of heavy metals in natural fruits without any pretreatment.This work is helpful to explore the distribution of heavy metals between pulp and peel.     

Studies of Al metabolism in animal by accelerator mass spectrometry

The correlation between Al metabolism and senile dementia in animal has been studied by AMS(accelerator mass spectrometry).Three groups of laboratory rats were fed with normal food.food with high Al content,and with enriched Ca and Mg together with high Al,respectively for six to eight months.Mapping test was made to recored th degree of wisdom degeneration.Half of the rats were sacrificed and Al contents in various organs were measured by atomic absorption spectroscopy.The rest were injected with ^26Al,killed after 5,10,15,25,and 35d and ^26Al contents measured by AMS.The distribution of Al as well as the correlation among the accumulation of ^26Al,and the existed Al content and dementia was studied.     

Assessment of some chemical element contents in Traganum nudatum Del shrub using instrumental neutron activation analysis

Instrumental neutron activation analysis(INAA)has been used to determine some chemical element contents(K,Ca,Na,Fe,Zn,Co,Eu,Sb,and Sc)in Traganum nudatum Del(Chenopodiaceae family)consumed in North African rangelands by sheep livestock.Samples were collected from the area of Djelfa in an arid steppe of Algeria.Results show that pasture halophyte had sufficient levels of K,Ca,Zn,and Co to meet the requirements of ruminants.However,it seems that this halophyte shrub had substantial amounts of Na,higher than the critical level established by the National Research Council(NRC).Eu,Sb,and Sc were within the safety baseline of all the assayed elements recommended by the NRC.The high Na content(～10 g/kg)in this halophytic species requires elevated intake of water by livestock.     

Calculation and characteristic analysis on synergistic effect of CF3I gas mixtures

CF_3I is a potential SF_6 alternative gas.In order to study the insulation properties and synergistic effects of CF_3I/N_2 and CF_3I/CO_2 gas mixtures,two-term approximate Boltzmann equations were used to obtain the ionization coefficient α,attachment coefficient η and the critical equivalent electrical field strength(E/N)_(cr).The results show that the(E/N)_(cr)of CF_3I gas at 300 K is 1.2 times that of SF_6 gas,and CF_3I/N_2 and CF_3I/CO_2 gas mixtures both have synergistic effect occurred.The synergistic effect coefficient of CF_3I/CO_2 gas mixture was higher than that of CF_3I/N_2 gas mixture.But the(E/N)_(cr)of CF_3I/N_2 is higher than that of CF_3I/CO_2 under the same conditions.When the content of CF_3I exceeds 20%,the (E/N)_(cr) of CF_3I/N_2 and CF_3I/CO_2 gas mixture increase linearly with the increasing of CF_3I gas content.The breakdown voltage of CF_3I/N_2 gas mixture is also higher than that of CF_3I/CO_2 gas mixture in slightly non-uniform electrical field under power frequency voltage,but the synergistic effect coefficients of the two gas mixtures are basically the same.     

Microarray screening of differentially expressed genes in DCX transfected U87 cells before and after irradiation

Radiation therapy plays a critical role in the treatment of neurogliocytoma and it is known that doublecortin (DCX)-transfected U87 cells can inhibit tumor cell growth. Microarray analysis to screen for differentially expressed genes in DCX-transfected U87 cells before and after radiation uncovered DCX-related genes, the functions of DCX, and downstream genes in radiation therapy of neurogliocytoma. Stably transfected U87 cells were constructed (DCX-U87) and the differentially expressed genes were screened by microarray analysis to compare U87 cells with DCX-U87 cells in both non-irradiated and irradiated conditions. Cells were irradiated using 60Co γ-ray at a dose rate of 1.0 Gy/min. Mean values were subject to paired comparison analysis and genes with a p-value of less than 0.05 were analyzed. Differentially expressed genes can correlate with radiation sensitivity and DCX transfection. DCX and SPN proteins in DCX-U87 cells were detected by two groups of 0 and 10 Gy, but not the U87 cells, and their expression levels were higher in the 10 Gy group than in the 0 Gy group. The differential gene expression in DCX-U87 cells before and after radiation is helpful for future investigations into the mechanisms of radiation therapy in neurogliocytoma cells.     

Investigation of the performance of CF_3I/c-C_4F_8/N_2 and CF_3I/c-C_4F_8/CO_2 gas mixtures from electron transport parameters

CF_3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF_6 gas, owing to their excellent insulating performance. This paper attempts to study the CF_3I ternary gas mixtures with c-C_4F_8 and buffer gases N_2 and CO_2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis, compared with SF_6 gas mixtures. The results confirm that the critical electric field strength of CF_3I/c-C_4F_8/70 % CO_2 is greater than that of 30% SF_6/70% CO_2 when the CF_3I content is greater than 17%. Moreover, a higher content of c-C_4F_8 decreases the sensitivity of gas mixtures to an electric field, and this phenomenon is more obvious in CF_3I/c-C_4F_8/CO_2 gas mixtures. The synergistic effects for CF_3I/c-C_4F_8/70 % N_2 were most obvious when the c-C_4F_8 content was approximately 20%, and for CF_3I/c-C_4F_8/70 % CO_2 when the c-C_4F_8 content was approximately 10%. On the basis of this research,CF_3I/c-C_4F_8/70 % N_2 shows better insulation performance when the c-C_4F_8 content is in the15%–20% range. For CF_3I/c-C_4F_8/70 % CO_2, when the c-C_4F_8 content is in the 10%–15%range, the gas mixtures have excellent performance. Hence, these gas systems might be used as alternative gas mixtures to SF_6 in high-voltage equipment.     

Numerical analysis on element creation by nuclear transmutation of fission products

A burnup calculation was performed to analyze the Apr`es ORIENT process, which aims to create highlyvaluable elements from fission products separated from spent nuclear fuels. The basic idea is to use nuclear transmutation induced by a neutron capture reaction followed by a β-decay, thus changing the atomic number Z of a target element in fission products by 1 unit. LWR(PWR) and FBR(MONJU) were considered as the transmutation devices. High rates of creation were obtained in some cases of platinum group metals(44Ru by FBR,46 Pd by LWR) and rare earth(64Gd by LWR,66 Dy by FBR). Therefore, systems based on LWR and FBR have their own advantages depending on target elements. Furthermore, it was found that creation rates of even Z(= Z + 1) elements from odd Z ones were higher than the opposite cases. This creation rate of an element was interpreted in terms of "average 1-group neutron capture cross section of the corresponding target element σc Z defined in this work. General trends of the creation rate of an even(odd) Z element from the corresponding odd(even) Z one were found to be proportional to the 0.78th(0.63th) power of σc Z, however with noticeable dispersion. The difference in the powers in the above analysis was explained by the difference in the number of stable isotopes caused by the even-odd effect of Z.     

TRACE ELEMENTAL ANALYSIS OF RAT CATARACTOUS LENSES BY PIXE

Cataracts were observed in the eye lenses of a group of Wistar rats that had been injected with Na2SeO3. The trace elemental analysis of their lenses was carried out by PIXE. The results showed that the variations of elemental contents were different between the injected rats and the controls. The elemental concentrations, which exhibited a certain regularity in their variations,could be related to the time of formation of cataract and to its state.     

APPLICATION OF NUCLEAR ANALYSIS TECHNIQUES IN STUDY OF ENVIRONMENTAL POLLUTION IN THE VICINITY OF SHANGHAI

Aerosol samples were collected from three typical areas during three years: 1) north suburb of Shanghai city (NSSC); 2) north part of Shanghai city; 3) a lead-zinc smeltery and its surrounding areas. The hair samples were collected from lead-exposed workers and control people. Aerosol samples have been analyzed by PIXE, and hair samples by EDXRF (energy-dispersive X-ray fluorescence) method. S, Cl, K, Ca, Mn, Fe, Cu, Zn, Pb etc were detected in most of the aerosol and hair samples. According to the analytical results, the compositions of NSSC aerosol samples were quite similar to those from north part of Shanghai city, both the lead concentrations of these samples were less than the limit of the National Standard (70 μ g/m3); There was serious air pollution in smeltery and its surrounding areas. Especially, the lead concentration in the aerosol exceeded 200 μg/m3; The average lead concentration of hair samples for half-year exposed group was about 3-fold higher than that of unexposed group.     

H22肝癌细胞与正常小鼠肝细胞胰岛素受体表达的对比

本实验采用氯胺T法进行了胰岛素的     

辐射后NFS-60细胞G-CSF受体特性的研究

为深化造血细胞辐射损伤分子机制的认识，应用受体放射分析法观察不同剂量照射的NFS—60细胞照射后不同时间粒细胞集落刺激因子(G—CSF)受体特性的变化。结果表明，NF5—60细胞照射后30min G—CSF受体的Kd值和Bmax值随着照射剂量的增大而增加，其中Kd值增加更为显著；照射后24h，1Gy照射细胞的Kd值及Bmax值已有恢复，3、5Gy照射细胞的Kd值未见下降，其Bmax值反而较照射后30min增加更为显著。提示照射后G—CSF受体Kd值的增加可能是造血细胞辐射损伤的原因之一。     

核电厂关键核素在海洋沉积物上的吸附动力学

为研究核电厂关键核素在海洋沉积物上的吸附动力学过程,通过静态批式实验获得三种沉积物对核素⁹⁰Sr、¹³⁷Cs、⁵⁴Mn、⁶⁰Co的吸附动力学曲线,采用多级吸附动力学模型对实验数据进行拟合,得出以下结论:⁹⁰Sr、¹³⁷Cs、⁵⁴Mn、⁶⁰Co在三种沉积物上的分配系数(K_d)分别为1.8～3.0、71.5～128.0、23.1～167.0、160.0～188.0 mL/g;采用一级吸附动力学模型所得K_d与实验所得K_d较为符合,说明4种核素在三种沉积物上的吸附行为可由一级吸附点位进行表征;获得了各样品的吸附动力学关键参数,包括吸附速率常数、解吸速率常数及单位最大吸附量。     

Hydrochlorination of acetylene over the Ru-based catalysts treated by plasma under different atmospheres

Ru-based catalysts modified in different atmospheres by plasma technology were prepared to catalyze the acetylene hydrochlorination reaction. The (Ru/AC)-N₂ (AC = activated carbon) catalyst yielded by the plasma modification of Ru/AC catalyst in N₂ atmosphere exhibits the best catalytic performance with a stable C₂H₂ conversion of 87.2%; a relative increase of 27.1% in C₂H₂ conversion was achieved compared with that of the untreated Ru/AC catalyst. The results of the analysis revealed that the modification produced a mutual effect between the generated function groups on carrier AC and the active components, which can disperse and yield more active species in the fresh catalysts. These are benefits of enhancing the activity of the catalysts. Moreover, the modification can restrain coke formation and inhibit the loss of active species in the reaction, as well as strengthen the adsorption ability of reactants on the catalysts. These are benefits of improving the catalysts’ performance.     

如何正确评价等长运动核素心血池显像诊断冠心病的临床价值

通过核素心血池显像测定静息和等长运动冠心病患者左室功能指标的变化，探讨等长运动核素心血池显像对冠心病诊断的临床价值。8例正常人、38例冠心病患者静息状态下核素心血池显像后，双手握力5—10min并同时进行采集从而获得静息和运动状态下两组心功能指标，并且行冠状动脉及左室造影。统计方法用t检验和四格表等效检验。结果表明，左室射血分数(LVEF)、高峰充盈率（PFR）、左室舒张末期容积（EDV）、左室收缩末期容积（ESV）和心率（HR）在静息状态下,对照组和冠心病一、二、三支冠脉病变组分别为(57±10.45)%、(53.67±5.0)%、(52.47±8.26)%、(52.81±8.89)%,p=NS;2.94±0.44、2.87±0.29、2.71±0.88、3.07±0.71(EDV/s),p=NS;1.38±0.15、1.36±0.05、1.34±0.06、1.34±0.06,p=NS;0.59±0.11、0.62±0.06、0.66±0.06、0.65±0.1,p=NS;72.88±8.25、69.67±8.14、72.85±10.5、76.56±18.04(min     

Effects of O2 addition on the plasma uniformity and reactivity of Ar DBD excited by ns pulsed and AC power supplies

Dielectric barrier discharges (DBDs) have been widely used in ozone synthesis, materials surface treatment, and plasma medicine for their advantages of uniform discharge and high plasma-chemical reactivity. To improve the reactivity of DBDs, in this work, the O₂ is added into Ar nanosecond (ns) pulsed and AC DBDs. The uniformity and discharge characteristics of Ar ns pulsed and AC DBDs with different O₂ contents are investigated with optical and electrical diagnosis methods. The DBD uniformity is quantitatively analyzed by gray value standard deviation method. The electrical parameters are extracted from voltage and current waveforms separation to characterize the discharge processes and calculate electron density n_e. The optical emission spectroscopy is measured to show the plasma reactivity and calculate the trend of electron temperature T_e with the ratio of two emission lines. It is found that the ns pulsed DBD has a much better uniformity than AC DBD for the fast rising and falling time. With the addition of O₂, the uniformity of ns pulsed DBD gets worse for the space electric field distortion by O₂⁻, which promotes the filamentary formation. While, in AC DBD, the added O₂ can reduce the intensity of filaments, which enhances the discharge uniformity. The ns pulsed DBD has a much higher instantaneous power and energy efficiency than AC DBD. The ratio of Ar emission intensities indicates that the T_e drops quickly with the addition of O₂ both ns pulsed and AC DBDs and the ns pulsed DBD has an obvious higher T_e and n_e than AC DBD. The results are helpful for the realization of the reactive and uniform low temperature plasma sources.     

Radio-ligand receptor binding assay in vitro and animal biodistribution in vivo of 99Tcm-N-ethyl-N2S2-memantine as a potential NMDA receptor imaging agent

The pharmacologic characteristics of 99Tcm-N-ethyl-N2S2-memantine,an NMDA receptor imaging agent,was investigated.It was prepared by a one-step reaction from N-ethyl-N2S2-memantine.The affinity and specificity were determined by radio-ligand receptor binding assay(RRA).Biodistribution in vivo in mice was performed.The results showed that 99Tcm-N-ethyl-N2S2-memantine bound to a single site on NMDA receptor with a Kd of 584.32 nmol/L and a Bmax of 267.05 nmol/mg.A competitive analysis showed that such specific binding could be inhibited by specific inhibitors of NMDA receptor,such as ketamine and(+)-MK-801.The biodistribution exhibited rapid uptake and favorable retention in mice brains.The major radioactivity was metabolized by the hepatic system.A two-compartment model of C=4.49e-0.083t+1.42e-0.0016t was established,and the half life was 8.35 min in blood.In conclusion,the new radio-ligand 99Tcm-N-ethyl-N2S2-Memantine has a moderate affinity and specific binding to NMDA receptor,and can easily cross the blood-brain barrier(BBB).Therefore,it may be a potential NMDA receptor imaging agent.     

Effect of parameter setting and spectral normalization approach on study of matrix effect by laser induced breakdown spectroscopy of Ag–Zn binary composites

The complex nature of laser-material interaction causes non-stoichiometric ablation of alloy samples.This is attributed to matrix effect, which reduces analyzing capability. To address this issue, the analytical performance of three different normalization methods, namely normalization with background, internal normalization and three point smoothing techniques at different parameter settings is studied for quantification of Ag and Zn by Laser induced breakdown spectroscopy(LIBS).The LIBS spectra of five known concentration of silver zinc binary composites have been investigated at various laser irradiances(LIs). Calibration curves for both Ag(I) line(4d~(10)5s~2S_(1/2)→4d~(10)5p~2P_(1/2) at 338.28 nm) and Zn(I) line(4s5s~3S_1→4s4p~3P_2 at 481.053 nm) have been determined at LI of 5.86?×?10~(10)W cm~(-2). Slopes of these calibration curves provide the valuation of matrix effect in the Ag–Zn composites. With careful sample preparation and normalization after smoothing at optimum parameter setting(OPS), the minimization of sample matrix effect has been successfully achieved. A good linearity has been obtained in Ag and Zn calibration curve at OPS when normalized the whole area of spectrum after smoothing and the obtained coefficients of determination values were R~2?=?0.995 and 0.998 closer to 1. The results of matrix effect have been further verified by analysis of plasma parameters. Both plasma parameters showed no change with varying concentration at OPS. However, at high concentration of Ag, the observed significant changes in both plasma parameters at common parameter setting PS-1 and PS-2 were the gesture of matrix effect. In our case, the better analytical results were obtained at smoothing function with optimized parameter setting that indicates it is more efficient than normalization with background and internal normalization method.     

Effect of ionizing radiation on the electrical characteristics ofpolyvinylidene fluoride (PVF2)

The influence of high-energy electron irradiation on the electrical properties of biaxially oriented polyvinylidene fluoride (PVF ₂) film was investigated. The film was irradiated in air with a 1-MeV electron beam at a dose rate of 10⁶ rad/min to different dose levels of up to 10⁸ rad. Electrical properties measured included dielectric permittivity and dielectric loss, AC and DC breakdown voltages, and DC volume resistivity, X-ray diffraction and IR spectroscopy measurements were also made. The most pronounced of the radiation-induced changes were a decrease in like AC breakdown voltage and an increase in dielectric loss, both corresponding to increasing total absorbed dose. DC breakdown voltage and volume resistivity also showed noticeable changes. These changes are believed to be associated initially with a radiation-induced crystal phase transformation. This was confirmed by the X-ray diffraction curve and the IR spectra, which showed an increase in the β-phase and a decrease in the α-phase peaks at higher dose levels     

半衰期为数天的惰性气体和卤素裂变产物在UO2颗粒中的扩散与释放

在考虑吸附效应等物理过程的基础上,得到了裂变产物在UO₂颗粒中扩散与释放模型的严格解,并导出了不同反应堆运行状态下裂变产物累积释放份额F(t)、释放-产出比R(t)/B(t)的严格表达式。利用上述结果以及相应的近似解、数值解,对半衰期为数天的惰性气体和卤素裂变产物（¹³¹I、¹³¹Xe^m、¹³³Xe和¹³³Xe^m）在不同堆芯历史条件下的F(t)和R(t)/B(t)进行了比较计算。分析表明,F(t)与R(t)/B(t)的结果均有所差别,但当反应堆运行时间达一定长度后,它们的数值相等。此外,严格解去掉了近似解中不必要的保守性,也比数值解更符合物理实际。