The Very Large Area gamma-ray Space Telescope(VLAST)is a mission concept proposed to detect gamma-ray photons through both Compton scattering and electron–positron pair production mechanisms,thus enabling the detecti...The Very Large Area gamma-ray Space Telescope(VLAST)is a mission concept proposed to detect gamma-ray photons through both Compton scattering and electron–positron pair production mechanisms,thus enabling the detection of photons with energies ranging from MeV to TeV.This project aims to conduct a comprehensive survey of the gamma-ray sky from a low-Earth orbit using an anti-coincidence detector,a tracker detector that also serves as a low-energy calorimeter,and a high-energy imaging calorimeter.We developed a Monte Carlo simulation application of the detector using the GEANT4 toolkit to evaluate the instrument performance,including the effective area,angular resolution,and energy resolution,and explored specific optimizations of the detector configuration.Our simulation-based analysis indicates that the current design of the VLAST is physically feasible,with an acceptance above 10 m^(2)sr which is four times larger than that of the Fermi-LAT,an energy resolution better than 2%at 10 GeV,and an angular resolution better than 0.2◦at 10 GeV.The VLAST project promises to make significant contributions to the field of gamma-ray astronomy and enhance our understanding of the cosmos.展开更多
In the future, the Very Large Area gamma-ray Space Telescope is expected to observe high-energy electrons and gamma rays in the MeV to TeV range with unprecedented acceptance. As part of the detector suite, a high-ene...In the future, the Very Large Area gamma-ray Space Telescope is expected to observe high-energy electrons and gamma rays in the MeV to TeV range with unprecedented acceptance. As part of the detector suite, a high-energy imaging calorimeter(HEIC) is currently being developed as a homogeneous calorimeter that utilizes long bismuth germanate(BGO) scintillation crystals as both absorbers and detectors. To accurately measure the energy deposition in the BGO bar of HEIC, a highdynamic-range readout method using a silicon photomultiplier(SiPM) and multiphotodiode(PD) with different active areas has been proposed. A prototype readout system that adopts multichannel charge measurement ASICs was also developed to read out the combined system of SiPMs and PDs. Preliminary tests confirmed the feasibility of the readout scheme, which is expected to have a dynamic range close to 10~6.展开更多
AIM: To investigate whether autologous dendritic cell (DC)-cytokine-induced killer (CIK) cell therapy is able to improve the therapeutic efficacy of chemotherapy in colon cancer.
Regeneration of transplantable pancreatic islet cells has been considered to be a promising alternative therapy for type 1 diabetes. Re-search has suggested that adult pancreatic stem and progenitor cells can be deriv...Regeneration of transplantable pancreatic islet cells has been considered to be a promising alternative therapy for type 1 diabetes. Re-search has suggested that adult pancreatic stem and progenitor cells can be derived into insulin-producing cells or cultivated islet-like clusters given appropriate stimulating condi- tions. In this study we explored the effect of selective extracellular matrix (ECM) proteins on the potential of insulin-producing cell differen-tiation using ARIP cells, an adult rat pancreatic ductal epithelial cell line, as a model in vitro. Quantitative single cell morphology analysis indicated that all the four ECM proteins we have used (type I collagen, laminin, fibronectin and vitronectin) increased the single cell area and diameter of ARIP cells. In addition, se-rum-free cell cultivation was dependent on cell density and particular components;and serum could be replaced when systematic optimisa-tion could be performed. Surface treated with laminin was shown to be able to enhance overall cell expansion in the presence of de-fined serum-free medium conditions. Collagen treated surfaces enhanced insulin production in the presence of GLP-1 although the insulin gene expression was however weak accord-ingly. Our results suggest that selective ECM proteins have effects on single cell morphol-ogy, adhesion and proliferation of ARIP cells. These ECM molecules however do not have a potent effect on the insulin-producing cell dif-ferentiation potential of ARIP cells even com-bining with GLP-1.展开更多
基金supported by the National Key Research and Development Program of China(No.2021YFA0718404)the National Natural Science Foundation of China(Nos.12220101003,12173098,U2031149)+2 种基金the Project for Young Scientists in Basic Research of Chinese Academy of Sciences(CAS)(No.YSBR-061)the Scientific Instrument Developing Project of CAS(No.GJJSTD20210009)the Youth Innovation Promotion Association of CAS,and the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(No.YESS20220197).
文摘The Very Large Area gamma-ray Space Telescope(VLAST)is a mission concept proposed to detect gamma-ray photons through both Compton scattering and electron–positron pair production mechanisms,thus enabling the detection of photons with energies ranging from MeV to TeV.This project aims to conduct a comprehensive survey of the gamma-ray sky from a low-Earth orbit using an anti-coincidence detector,a tracker detector that also serves as a low-energy calorimeter,and a high-energy imaging calorimeter.We developed a Monte Carlo simulation application of the detector using the GEANT4 toolkit to evaluate the instrument performance,including the effective area,angular resolution,and energy resolution,and explored specific optimizations of the detector configuration.Our simulation-based analysis indicates that the current design of the VLAST is physically feasible,with an acceptance above 10 m^(2)sr which is four times larger than that of the Fermi-LAT,an energy resolution better than 2%at 10 GeV,and an angular resolution better than 0.2◦at 10 GeV.The VLAST project promises to make significant contributions to the field of gamma-ray astronomy and enhance our understanding of the cosmos.
基金Foundation of China (Nos. 12227805, U1831206, 12103095, 12235012, 12273120, and 11973097)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (No. GJJSTD20210009)。
文摘In the future, the Very Large Area gamma-ray Space Telescope is expected to observe high-energy electrons and gamma rays in the MeV to TeV range with unprecedented acceptance. As part of the detector suite, a high-energy imaging calorimeter(HEIC) is currently being developed as a homogeneous calorimeter that utilizes long bismuth germanate(BGO) scintillation crystals as both absorbers and detectors. To accurately measure the energy deposition in the BGO bar of HEIC, a highdynamic-range readout method using a silicon photomultiplier(SiPM) and multiphotodiode(PD) with different active areas has been proposed. A prototype readout system that adopts multichannel charge measurement ASICs was also developed to read out the combined system of SiPMs and PDs. Preliminary tests confirmed the feasibility of the readout scheme, which is expected to have a dynamic range close to 10~6.
基金Supported by National Natural Science Foundation of China,No.31171427 and No.30971651 to Wang ZXNational Natural Science Foundation of China,No.30700974 to Cao JXPostdoctoral Foundation of China,No.20060400775 to Cao JX
文摘AIM: To investigate whether autologous dendritic cell (DC)-cytokine-induced killer (CIK) cell therapy is able to improve the therapeutic efficacy of chemotherapy in colon cancer.
文摘Regeneration of transplantable pancreatic islet cells has been considered to be a promising alternative therapy for type 1 diabetes. Re-search has suggested that adult pancreatic stem and progenitor cells can be derived into insulin-producing cells or cultivated islet-like clusters given appropriate stimulating condi- tions. In this study we explored the effect of selective extracellular matrix (ECM) proteins on the potential of insulin-producing cell differen-tiation using ARIP cells, an adult rat pancreatic ductal epithelial cell line, as a model in vitro. Quantitative single cell morphology analysis indicated that all the four ECM proteins we have used (type I collagen, laminin, fibronectin and vitronectin) increased the single cell area and diameter of ARIP cells. In addition, se-rum-free cell cultivation was dependent on cell density and particular components;and serum could be replaced when systematic optimisa-tion could be performed. Surface treated with laminin was shown to be able to enhance overall cell expansion in the presence of de-fined serum-free medium conditions. Collagen treated surfaces enhanced insulin production in the presence of GLP-1 although the insulin gene expression was however weak accord-ingly. Our results suggest that selective ECM proteins have effects on single cell morphol-ogy, adhesion and proliferation of ARIP cells. These ECM molecules however do not have a potent effect on the insulin-producing cell dif-ferentiation potential of ARIP cells even com-bining with GLP-1.