1.27μm波段的氧分子近红外气辉是火星大气最重要的气辉辐射之一,该气辉高光谱分辨辐射传输模型的建立对于研制火星探测载荷,反演火星大气的风场温度场与臭氧浓度,以及研究火星空间物理,有重要的科学价值与工程意义.在研究火星大气O_(2)...1.27μm波段的氧分子近红外气辉是火星大气最重要的气辉辐射之一,该气辉高光谱分辨辐射传输模型的建立对于研制火星探测载荷,反演火星大气的风场温度场与臭氧浓度,以及研究火星空间物理,有重要的科学价值与工程意义.在研究火星大气O_(2)(a^(1)Δ_(g))气辉光化学反应模型的基础上,提出了O_(2)(a^(1)Δ_(g))气辉体辐射率的计算方法,并建立了火星大气气辉辐射传输理论;通过与用于研究火星大气特征的光谱学探测仪(Spectroscopy Spectrograph for the Investigation of Characteristics of the Atmosphere of Mars,SPICAM)的实测数据进行对比,验证了所建立的火星O_(2)(a^(1)Δ_(g))气辉高光谱分辨辐射传输模型的准确性;针对火星与地球大气的O_(2)(a^(1)Δ_(g))气辉,在体辐射率、自吸收效应,以及临边辐射光谱特性三个方面进行了系统深入的比较,对比结果表明,火星大气由于密度低、氧气丰度小,其自吸收效应可以忽略不计,但其O_(2)(a^(1)Δ_(g))气辉辐射强度与地球大气相当,可以用于火星大气的风场温度场与臭氧浓度的探测与反演.展开更多
High-resolution ro-vibrational spectroscopy of ^15N2^16O in 1650-3450 cm-1 region is studied using highly enriched isotopologue sample. The positions of more than 7300 lines of ^15N2^16O isotopologue were measured wit...High-resolution ro-vibrational spectroscopy of ^15N2^16O in 1650-3450 cm-1 region is studied using highly enriched isotopologue sample. The positions of more than 7300 lines of ^15N2^16O isotopologue were measured with a typical accuracy of 5.0×10-4 cm-1. The transitions were rovibrationally assigned on the basis of the global effective Hamiltonian model. The band by band analysis allowed for the determination of the rovibrational parameters of a total of 73 bands. 29 of them are newly reported and more rotational transitions have been observed for the others. The maximum deviation of the preidictions of the effective Hamiltonian model is up to 0.70 cm-1 for the ^15N2^16O species.展开更多
lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synt...lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synthesized by a low-temperature hydrothermal method using a tai-lored diquaternary ammonium surfactant as the structure-directing agent.Introducing Ni^2+cationsat the ion-exchange sites of the TS-1 NS framework significantly enhanced its photoactivity in aero-bic alcohol oxidation.The optimized Ni cation-functionalized TS-1 NS(Ni/TS-1 NS)provide impres-sive photoactivity,with a benzyl alcohol(BA)conversion of 78.9%and benzyl aldehyde(BAD)se-lectivity of 98.8%using O as the only oxidant under full light irradiation;this BAD yield is approx-imately six times greater than that obtained for bulk TS-1,and is maintained for five runs.The ex-cellent photoactivity of Ni/TS-1 NS is attributed to the significantly enlarged surface area of thetwo-dimensional morphology TS-1 NS,extra mesopores,and greatly improved charge separation.Compared with bulk TS-1,Ni/TS-1 NS has a much shorter charge transfer distance.Theas-introduced Ni species could capture the photoelectrons to further improve the charge separa-tion.This work opens the way to a class of highly selective,robust,and low-cost titanosilicate mo-lecular sieve-based photocatalysts with industrial potential for selective oxidative transformationsand pollutant degradation.展开更多
AIM: To study the cell cycle alterations of human hepatoma cell line HepG2 in vitro after ^60Co γ-irradiation and further to examine the mechanisms underlying the enhancement of radiosensitivity to γ-irradiation in ...AIM: To study the cell cycle alterations of human hepatoma cell line HepG2 in vitro after ^60Co γ-irradiation and further to examine the mechanisms underlying the enhancement of radiosensitivity to γ-irradiation in HepG2 transiently transfected with wild type p27^kip1. METHODS: The proliferation of HepG2 cells was evaluated with MTT assay, and the cell cycle profile and apoptosis were assessed by cell morphology, DNA fragmentation analysis and flow cytometry. HepG2 cells were transfectedwith p27^kip1 wild type by using Lipofectamine (LF2000), and the expression and subcellular localization of p27^kip1 in HepG2 were detected by immunocytochemistry.RESULTS: ^60Co γ-irradiation inhibited the growth of HepG2 cells in a dose-dependent manner. Apoptosis of HepG2 cells was induced 48 h after ~, ray exposure. Furthermore research was carried out to induce exogenous expression of p27^kip1 in HepG2. The expression of p27^kip1 induced G0/G1 phase arrest in HepG2 cells. The overexpression of p27^kip1 enhanced ^60Co γ-irradiation-induced radiosensitivity in HepG2 cells. CONCLUSION: Overexpression of p27^kip1 is a rational approach to improve conventional radiotherapy outcomes, which may be a possible strategy for human hepatoma therapy.展开更多
文摘1.27μm波段的氧分子近红外气辉是火星大气最重要的气辉辐射之一,该气辉高光谱分辨辐射传输模型的建立对于研制火星探测载荷,反演火星大气的风场温度场与臭氧浓度,以及研究火星空间物理,有重要的科学价值与工程意义.在研究火星大气O_(2)(a^(1)Δ_(g))气辉光化学反应模型的基础上,提出了O_(2)(a^(1)Δ_(g))气辉体辐射率的计算方法,并建立了火星大气气辉辐射传输理论;通过与用于研究火星大气特征的光谱学探测仪(Spectroscopy Spectrograph for the Investigation of Characteristics of the Atmosphere of Mars,SPICAM)的实测数据进行对比,验证了所建立的火星O_(2)(a^(1)Δ_(g))气辉高光谱分辨辐射传输模型的准确性;针对火星与地球大气的O_(2)(a^(1)Δ_(g))气辉,在体辐射率、自吸收效应,以及临边辐射光谱特性三个方面进行了系统深入的比较,对比结果表明,火星大气由于密度低、氧气丰度小,其自吸收效应可以忽略不计,但其O_(2)(a^(1)Δ_(g))气辉辐射强度与地球大气相当,可以用于火星大气的风场温度场与臭氧浓度的探测与反演.
基金This work is supported by the National Natural Science Foundation of China （No.20903085）, the NKBRSF 2010CB9230, and RFBR-Russia （No.06-05- 39016）. The support of the Groupement de Recherche International SAMIA （Spectroscopie d＇Absorption des Mol@cules d＇Interet Atmospherique） between CNRS （France）, RFBR （Russia） and CAS （China） is also acknowledged.
文摘High-resolution ro-vibrational spectroscopy of ^15N2^16O in 1650-3450 cm-1 region is studied using highly enriched isotopologue sample. The positions of more than 7300 lines of ^15N2^16O isotopologue were measured with a typical accuracy of 5.0×10-4 cm-1. The transitions were rovibrationally assigned on the basis of the global effective Hamiltonian model. The band by band analysis allowed for the determination of the rovibrational parameters of a total of 73 bands. 29 of them are newly reported and more rotational transitions have been observed for the others. The maximum deviation of the preidictions of the effective Hamiltonian model is up to 0.70 cm-1 for the ^15N2^16O species.
文摘lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synthesized by a low-temperature hydrothermal method using a tai-lored diquaternary ammonium surfactant as the structure-directing agent.Introducing Ni^2+cationsat the ion-exchange sites of the TS-1 NS framework significantly enhanced its photoactivity in aero-bic alcohol oxidation.The optimized Ni cation-functionalized TS-1 NS(Ni/TS-1 NS)provide impres-sive photoactivity,with a benzyl alcohol(BA)conversion of 78.9%and benzyl aldehyde(BAD)se-lectivity of 98.8%using O as the only oxidant under full light irradiation;this BAD yield is approx-imately six times greater than that obtained for bulk TS-1,and is maintained for five runs.The ex-cellent photoactivity of Ni/TS-1 NS is attributed to the significantly enlarged surface area of thetwo-dimensional morphology TS-1 NS,extra mesopores,and greatly improved charge separation.Compared with bulk TS-1,Ni/TS-1 NS has a much shorter charge transfer distance.Theas-introduced Ni species could capture the photoelectrons to further improve the charge separa-tion.This work opens the way to a class of highly selective,robust,and low-cost titanosilicate mo-lecular sieve-based photocatalysts with industrial potential for selective oxidative transformationsand pollutant degradation.
基金Supported by the National Postdoctor Research Foundation of China,No.2003034383
文摘AIM: To study the cell cycle alterations of human hepatoma cell line HepG2 in vitro after ^60Co γ-irradiation and further to examine the mechanisms underlying the enhancement of radiosensitivity to γ-irradiation in HepG2 transiently transfected with wild type p27^kip1. METHODS: The proliferation of HepG2 cells was evaluated with MTT assay, and the cell cycle profile and apoptosis were assessed by cell morphology, DNA fragmentation analysis and flow cytometry. HepG2 cells were transfectedwith p27^kip1 wild type by using Lipofectamine (LF2000), and the expression and subcellular localization of p27^kip1 in HepG2 were detected by immunocytochemistry.RESULTS: ^60Co γ-irradiation inhibited the growth of HepG2 cells in a dose-dependent manner. Apoptosis of HepG2 cells was induced 48 h after ~, ray exposure. Furthermore research was carried out to induce exogenous expression of p27^kip1 in HepG2. The expression of p27^kip1 induced G0/G1 phase arrest in HepG2 cells. The overexpression of p27^kip1 enhanced ^60Co γ-irradiation-induced radiosensitivity in HepG2 cells. CONCLUSION: Overexpression of p27^kip1 is a rational approach to improve conventional radiotherapy outcomes, which may be a possible strategy for human hepatoma therapy.
