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Design of CsI(TI) detector system to search for lost radioactive source

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Nuclear Science and Techniques 2019年第9期30卷 9-17页

作者： Waseem Khan Chao-Hui He Qing-Min Zhang yu Cao wei-Tao Yang Department of Nuclear Science and Technology School of Energy and Power Engineering Xi’an Jiaotong University

This report presents a design system based on the use of CsI(TI) detectors to search for lost radioactive sources that are dangerous and harmful to individuals, including searching persons. For this purpose, the GEANT4 simulation toolkit was utilized to develop a system based on three detectors. Various simulated analyses were performed on the dose rates of the three detectors using different source–detector distances and detector separation. There were good agreement between the simulated results and the experimentally measured data. A new method was discussed to detect and search for radioactive sources based only on the dose rates in detectors with source activity. Numerical analyses were performed based on the measured dose rates and the difference of distances to determine the actual location of the lost single or multiple γ-ray sources at a specific angle. The detection limit was calculated from the background radiation to establish the sensitivity and capability of the proposed detector system. This system can be applied in fields in which it is necessary to locate unknown radioactive sources.

关键词： GEANT4 γ-Ray source CsI(TI) detectors

Ammonia promotes the proliferation of bone marrow-derived mesenchymal stem cells by regulating the Akt/mTOR/S6k pathway

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Bone Research 2022年第4期10卷 838-851页

作者： yu Liu Xiangxian Zhang wei Wang Ting Liu Jun Ren Siyuan Chen Tianqi Lu Yan Tie Xia yuan Fei Mo Jingyun Yang yuquan wei Xiawei wei Laboratory of Aging Research and Cancer Drug Target State Key Laboratory of Biotherapy and Cancer CenterNational Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityNo.17Block 3Southern Renmin RoadChengduSichuan 610041PR China Department of Clinical Laboratory The West China Second University Hospital of Sichuan University(WCSUH-SCU)Sichuan UniversityNo.17Block 3Southern Renmin RoadChengduSichuan 610041PR China Department of Prenatal Diagnosis Center The West China Second University Hospital of Sichuan University(WCSUH-SCU)Sichuan UniversityNo.17Block 3Southern Renmin RoadChengduSichuan 610041PR China

Ammonia plays an important role in cellular ***,ammonia is considered a toxic *** bone marrow-derived mesenchymal stem cells,multipotent stem cells with high expression of glutamine synthetase(GS)in bone marrow,ammonia and glutamate can be converted to glutamine via glutamine synthetase activity to support the proliferation of *** a major nutritional amino acid for biosynthesis,glutamine can activate the Akt/mTOR/S6k pathway to stimulate cell *** activation of mTOR can promote cell entry into S phase,thereby enhancing DNA synthesis and cell *** studies demonstrated that mesenchymal stem cells can convert the toxic waste product ammonia into nutritional glutamine via GS ***,the Akt/mTOR/S6k pathway is activated to promote bone marrow-derived mesenchymal stem cell *** results suggest a new therapeutic strategy and potential target for the treatment of diseases involving hyperammonemia.

关键词： Ammonia ammonia diseases

Fiber-based photonic crystal reflectors with fractional bandwidths in excess of 10%

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量子电子学报 2014年第1期 125-126页

作者： yu Yang DING wei LI Zhi-yuan Laboratory of Optical Physics Institute of PhysicsChinese Academy of Sciences

It is experimentally exhibited that optical reflectors with the reflectivity in excess of 60%and the fractional bandwidth in excess of 10%can be fabricated by drilling less than ten periodic through-holes in micronscale fiber *** one-dimensional(1D)photonic crystal(PhC)devices make use of the refractive index contrast in the silica/air context to the maximum extent and bring unprecedented size ***,the radiation losses at the central wavelength of the photonic bandgap(PBG)generated in these PhC reflectors are measured and interpreted by interferometric mechanisms.A PhC reflector was fabricated in a silica fiber taper with the fractional reflection bandwidth in excess of 10%and the device length of several *** measured spectra agree well with the *** losses of the devices at the central wavelengths of the PBGs were measured and the undulation with the increase of the period number was *** interferometric interactions between component radiation beams may explain this *** addition,by drilling through-holes in micron-dimension fiber tapers and then safely suspending them into the air,a sufficiently large mechanical strength of this optical micro-wire was *** these unique properties open the possibility of fabricating more complicated structures in this fiber-based optical waveguide.

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Effects of Initial Conditions on Energy Distribution of Suprathermal Electrons in Interaction of Intense Ultrashort Laser Pulse with a Preplasma

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Chinese Physics Letters 1999年第1期16卷 35-37页

作者： LIU Shi-bing ZHANG Jie yu wei ZHANG Guang-cai Institute of Physics Chinese Academy of SciencesBeijing 100080 CCAST(World Laboratory) P.O.Box 8730Beijing 100080 Department of Physics University of OxfordOxfordOX13PUUK Shanghai Institute of Optics and Fine Mechanics Chinese Academy of SciencesShanghai 201800

Relativistic momentum and energy equations of electrons in an intense laser field are derived with Hamilton-Jacobi *** initial electrons in non-equilibrium or Maxwellian equilibrium distributions in preplasmas,suprathermal electron energy distributions are obtained analytically and *** calculation results agree well with the experiments.

关键词： thermal equilibrium Electron

Studies on the Effects of Epimedium Extract on Erythrocytes

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Chinese Chemical Letters 2006年第8期17卷 1105-1108页

作者： Xiao yu ZHANG Feng Hua CHEN Ping Hui wei Jia Zuan NI Department of Biological Engineering College of Environment ＆ Chemical Engineering Yanshan University Hebei 066004 Key Laboratory of Rare Earth Chemistry and Physics Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022

The effect of Epimedium extract （EE） on erythrocytes was investigated by atomic force microscopy （AFM）. The images of the surface structures showed clear concave and progressive increase of surface roughness of erythrocyte after incubation with EE at concentration of 0.2 or 0.05 g/L, far below its critical hemolytic levels. The AFM results also indicated that the granules of the fine surface structure increased, which caused by aggregation of membrane protein. Further study showed that the change in surface topography of erythrocyte membrane might be connected with the increase of intracellular free Ca^2＋ induced by EE.

关键词： AFM Epimedium extract (EE) erythrocyte intracellular free Ca^2+.

Diffuse invasive signet ring cell carcinoma in total colorectum caused by ulcerative colitis:A case report and review of literature

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World Journal of Clinical Cases 2022年第5期10卷 1729-1737页

作者： Zhi Zhang Peng-Fei yu Guo-Li Gu yu-Hui Zhang yu-Ming Wang Zhi-wei Dong Hai-Rui Yang Department of General Surgery Air Force Medical CenterChinese People's Liberation ArmyBeijing 100142China Graduate School Hebei North UniversityZhangjiakou 075000Hebei ProvinceChina Health Team 93656 Troop of Chinese People's Liberation ArmyBeijing 101113China

BACKGROUND Diffuse invasive signet ring cell carcinoma of the colorectum is extremely rare *** type of colorectal cancer has certain clinical,pathological and biological characteristics that are different from ordinary colorectal *** SUMMARY A 31-year-old young woman was admitted to the hospital for nearly 1 wk due to recurrent symptoms of mucopurulent bloody stools and abdominal *** colonoscopy showed a ring-shaped intestinal wall mass 10 cm from the rectum to the *** pieces of tumor tissue were removed for *** pathological results showed rectal mucinous *** patient underwent laparoscopic exploration under general anesthesia,and then laparoscopic total colorectal resection,ileal pouch–anal anastomosis and ileostomy were *** patient was switched to a FOLFOX+cetuximab *** the fifth cycle,the patient was unable to tolerate further treatment due to tumor progression and multiple organ dysfunction,and died at the end of May *** survival was 7 *** Carcinogenesis of ulcerative colitis is different from sporadic colon cancer,and the overall prognosis is extremely poor.

关键词： Ulcerative colitis Colorectal cancer Signet ring cell carcinoma Case report

Pyrolysis of Glucose over Two Amphoteric Metal Oxides

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Chemical Research in Chinese Universities 2009年第2期25卷 234-238页

作者： YANG yu XIANG Xi LUO Jia QI wei-Yan YAN Hong-Peng LI Gui-Ying HU Chang-wei Key Laboratory of Green Chemistry and Technology Ministry of Education College of Chemistry Sichuan University Chengdu 610064 P. R. China

The catalytic pyrolysis of glucose over amphoteric metal oxide, ZnO or γ-l2O3, was studied comparatively with direct pyrolysis. The effects of catalyst to glucose ratio on the yields of pyrolytic products and on the chemical composition of the liquid products were discussed. Compared with the pyrolytic products of direct pyrolysis, the amount of residual char decreased, whereas the gas yield increased in the presence of the catalysts. The highest liquid yield over ZNO（49.5%） was obtained when the ratio of ZnO to glucose was 5%, whereas over γ-Al2O3 the liquid yield increased with increasing the amount of γ-Al2O3 added. The presence of both the catalysts enhanced the selectivity to furans in liquid and reduced that of anhydro sugars. A selectivity of 69.7% to furans was obtained over 1% ZnO with a selectivity of 14.6% to 5-hydroxymethylfurfural（HMF）. The maximum selectivity to furans（74.9%） and that to HMF（25.6%） were obtained in the presence of 10% γ-Al2O3.

关键词： Glucose ZnO γ-Al2O3 Furans 5-Hydroxymethylfurfural

Adjuvant percutaneous radiofrequency ablation of feeding artery of hepatocellular carcinoma before treatment

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World Journal of Gastroenterology 2009年第21期15卷 2638-2643页

作者： Yi-Bin Hou Min-Hua Chen Kun Yan Jin-yu Wu wei Yang Ultrasound Department Peking University School of Oncology Cancer Hospital & Institute No. 52 Fucheng Road Haidian District Beijing 100142 China

AIM:To evaluate the feasibility and efficacy of percutaneous radiofrequency ablation(RFA) of the feeding artery of hepatocellular carcinoma(HCC) in reducing the blood-flow-induced heat-sink effect of ***:A total of 154 HCC patients with 177 pathologically confirmed hypervascular lesions participated in the study and were randomly assigned into two ***-one patients with 75 HCCs(average tumor size,4.3 ± 1.1 cm) were included in group A,in which the feeding artery of HCC was identified by color Doppler flow imaging,and were ablated with multiple small overlapping RFA foci [percutaneous ablation of feeding artery(PAA)] before routine RFA treatment of the ***-three patients with 102 HCC(average tumor size,4.1 ± 1.0 cm) were included in group B,in which the tumors were treated routinely with ***-enhanced computed tomography was used as post-RFA imaging,when patients were followed-up for 1,3 and 6 ***:In group A,feeding arteries were blocked in 66(88%) HCC lesions,and the size of arteries decreased in nine(12%).The average number of punctures per HCC was 2.76 ± 1.12 in group A,and 3.36 ± 1.60 in group B(P = 0.01).The tumor necrosis rate at 1 mo post-RFA was 90.67%(68/75 lesions) in group A and 90.20%(92/102 lesions) in group *** recur-rence rate at 6 mo post-RFA was 17.33%(13/75) in group A and 31.37%(32/102) in group B(P = 0.04).CONCLUSION:PAA blocked effectively the feeding artery of *** of PAA and RFA significantly decreased post-RFA recurrence and provided an alternative treatment for hypervascular HCC.

关键词： Hepatocellular carcinoma Feeding artery Radiofrequency ablation Recurrence Color Dopplerflow imaging

Driving factors of carbon dioxide emissions in China： an empirical study using 2006-2010 provincial data

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Frontiers of Earth Science 2017年第1期11卷 156-161页

作者： yu LIU Zhan-Ming CHEN Hongwei XIAO wei YANG Danhe LIU Bin CHEN Institute of Policy and Management Chinese Academy of Sciences Beijing 100190 China Department of Energy Economics School of Economics Renmin University of China Beijing 100872 China National Academy of Development and Strategy Renmin University of China Beijing 100872 China Economic Forecasting Department State Information Center Beijing 100045 China School of Economics and Management Beijing University of Chemical Technology Beijing 100029 China School of Humanities and Social Science Beijing Institute of Technology Beijing 100081 China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China

The rapid urbanization of China has increased pressure on its environmental and ecological well being. In this study, the temporal and spatial profiles of China＇s carbon dioxide emissions are analyzed by taking heterogeneities into account based on an integration of the extended stochastic impacts using a geographically and temporally weighted regression model on population, affluence, and technology. Population size, urbanization rate, GDP per capita, energy intensity, industrial structure, energy consumption pattern, energy prices, and economy openness are identified as the key driving factors of regional carbon dioxide emissions and examined through the empirical data for 30 provinces during 2006-2010. The results show the driving factors and their spillover effects have distinct spatial and temporal heterogeneities. Most of the estimated time and space coefficients are consistent with expectation. According to the results of this study, the heterogeneous spatial and temporal effects should be taken into account when designing policies to achieve the goals of carbon dioxide emissions reduction in different regions.

关键词： carbon dioxide emission heterogeneity space spillover