The smuggling of special nuclear materials(SNMs)across national borders is becoming a serious threat to nuclear nonproliferation.This paper presents a feasibility study on the rapid interrogation of concealed SNMs by ...The smuggling of special nuclear materials(SNMs)across national borders is becoming a serious threat to nuclear nonproliferation.This paper presents a feasibility study on the rapid interrogation of concealed SNMs by combining scattering and transmission nuclear resonance fluorescence(s NRF and t NRF)spectroscopy.In s NRF spectroscopy,SNMs such as^(235,238)U are excited by a wide-band photon beam of appropriate energy and exhibit unique NRF signatures.Monte Carlo simulations show that one-dimensional scans can realize isotopic identification of concealed^(235,238)U when the detector array used for interrogation has sufficiently high energy resolution.The simulated isotopic ratio^(235U/238)U is in good agreement with the theoretical value when the SNMs are enclosed in relatively thin iron.This interrogation is followed by t NRF spectroscopy using a narrow-band photon beam with the goal of obtaining tomographic images of the concealed SNMs.The reconstructed image clearly reveals the position of the isotope^(235)U inside an iron rod.It is shown that the interrogation time of s NRF and t NRF spectroscopy is one order of magnitude lower than that when only t NRF spectroscopy is used and results in a missed-detection rate of 10^(-3).The proposed method can also be applied for isotopic imaging of other SNMs such as^(239,240)Pu and^(237)Np.展开更多
合成了3种可聚合的1,8-萘酰亚胺衍生物,并研究了其在二甲基亚砜(DMSO)溶液中的光物理性质.这些化合物表现出的光物理性质与其电子环境有关.通过溶胶-凝胶法制备了可聚合1,8-萘酰亚胺衍生物与硅氧烷的共聚物.尽管3种萘酰亚胺衍生物C-4位...合成了3种可聚合的1,8-萘酰亚胺衍生物,并研究了其在二甲基亚砜(DMSO)溶液中的光物理性质.这些化合物表现出的光物理性质与其电子环境有关.通过溶胶-凝胶法制备了可聚合1,8-萘酰亚胺衍生物与硅氧烷的共聚物.尽管3种萘酰亚胺衍生物C-4位的取代基不同,但在3-氨丙基三乙氧基硅烷(APTES)固凝胶中摩尔分数为0.06%时荧光强度均最大.利用29Si MAS NMR对合成材料进行了表征,结果表明,硅氧烷的缩聚程度影响材料的荧光强度,说明材料中荧光单元的分子运动对材料的荧光性能有重要影响.展开更多
环境内分泌干扰物(endocrine disrupting chemicals,EDCs)可模仿或拮抗天然激素与核受体结合,干扰核受体的同源或异源二聚,进而通过共调节因子的招募调控转录活性,最终引起内分泌干扰效应。目前研究主要针对EDCs与核受体的结合过程,忽...环境内分泌干扰物(endocrine disrupting chemicals,EDCs)可模仿或拮抗天然激素与核受体结合,干扰核受体的同源或异源二聚,进而通过共调节因子的招募调控转录活性,最终引起内分泌干扰效应。目前研究主要针对EDCs与核受体的结合过程,忽视了其对核受体二聚化过程的影响,而该过程的阻断可直接导致转录失活。EDCs对于不同核受体二聚化的影响不同,只有激动剂EDCs能够促进雄激素受体(androgen receptor,AR)的同源二聚化,而雌激素受体(estrogen receptor,ER)在与具有激动或拮抗活性的EDCs结合后都可诱导ER二聚体的形成,但二聚化类型不同。通过检索ToxCast和Tox21数据库发现多达227种EDCs可以诱导ER二聚化,相比于ERα-ERα同源二聚体(6.09%~7.38%的活性率),EDCs更易诱导ERα-ERβ异源二聚体(11.25%~12.22%的活性率)和ERβ-ERβ同源二聚体(10.02%~11.69%的活性率)。EDCs也能够差异性诱导其他核受体如维生素D受体(vitamin D receptor,VDR)与维甲酸X受体(retinoid X receptor,RXR)形成的异源二聚体,不同类型的二聚体对于研究EDCs转录活性的生理学相关性具有重要意义。基于经济合作与发展组织(Organization for Economic Co-operation and Development,OECD)报告的参考化学品研究发现,相比于配受体结合活性,二聚活性与转录活性之间有着更好的相关关系。本文从EDCs介导的核受体二聚化转录机制、二聚化与转录活性间的关系以及二聚化研究方法三方面,总结EDCs对核受体二聚化的影响,以期为深入理解EDCs的分子作用机制,推进化合物的内分泌干扰风险评估提供参考。展开更多
基金supported by the National Natural Science Foundation of China(No.11675075)Youth Talent Project of Hunan Province,China(No.2018RS3096)+1 种基金Independent Research Project of Key Laboratory of Plasma Physics,CAEP(No.JCKYS2020212006)Innovation and Entrepreneurship Training Program for College Students of University of South China(No.X2019083)。
文摘The smuggling of special nuclear materials(SNMs)across national borders is becoming a serious threat to nuclear nonproliferation.This paper presents a feasibility study on the rapid interrogation of concealed SNMs by combining scattering and transmission nuclear resonance fluorescence(s NRF and t NRF)spectroscopy.In s NRF spectroscopy,SNMs such as^(235,238)U are excited by a wide-band photon beam of appropriate energy and exhibit unique NRF signatures.Monte Carlo simulations show that one-dimensional scans can realize isotopic identification of concealed^(235,238)U when the detector array used for interrogation has sufficiently high energy resolution.The simulated isotopic ratio^(235U/238)U is in good agreement with the theoretical value when the SNMs are enclosed in relatively thin iron.This interrogation is followed by t NRF spectroscopy using a narrow-band photon beam with the goal of obtaining tomographic images of the concealed SNMs.The reconstructed image clearly reveals the position of the isotope^(235)U inside an iron rod.It is shown that the interrogation time of s NRF and t NRF spectroscopy is one order of magnitude lower than that when only t NRF spectroscopy is used and results in a missed-detection rate of 10^(-3).The proposed method can also be applied for isotopic imaging of other SNMs such as^(239,240)Pu and^(237)Np.
文摘合成了3种可聚合的1,8-萘酰亚胺衍生物,并研究了其在二甲基亚砜(DMSO)溶液中的光物理性质.这些化合物表现出的光物理性质与其电子环境有关.通过溶胶-凝胶法制备了可聚合1,8-萘酰亚胺衍生物与硅氧烷的共聚物.尽管3种萘酰亚胺衍生物C-4位的取代基不同,但在3-氨丙基三乙氧基硅烷(APTES)固凝胶中摩尔分数为0.06%时荧光强度均最大.利用29Si MAS NMR对合成材料进行了表征,结果表明,硅氧烷的缩聚程度影响材料的荧光强度,说明材料中荧光单元的分子运动对材料的荧光性能有重要影响.
基金the major scientific instruments and equipment development project of the Ministry of Science and Technology,China(2012YQ18011805)the science and technology project from the technology bureau of Chengdu(2014HM0100099SF)the project of science and technology innovation team of Sichuan province(2015TD0020)
文摘环境内分泌干扰物(endocrine disrupting chemicals,EDCs)可模仿或拮抗天然激素与核受体结合,干扰核受体的同源或异源二聚,进而通过共调节因子的招募调控转录活性,最终引起内分泌干扰效应。目前研究主要针对EDCs与核受体的结合过程,忽视了其对核受体二聚化过程的影响,而该过程的阻断可直接导致转录失活。EDCs对于不同核受体二聚化的影响不同,只有激动剂EDCs能够促进雄激素受体(androgen receptor,AR)的同源二聚化,而雌激素受体(estrogen receptor,ER)在与具有激动或拮抗活性的EDCs结合后都可诱导ER二聚体的形成,但二聚化类型不同。通过检索ToxCast和Tox21数据库发现多达227种EDCs可以诱导ER二聚化,相比于ERα-ERα同源二聚体(6.09%~7.38%的活性率),EDCs更易诱导ERα-ERβ异源二聚体(11.25%~12.22%的活性率)和ERβ-ERβ同源二聚体(10.02%~11.69%的活性率)。EDCs也能够差异性诱导其他核受体如维生素D受体(vitamin D receptor,VDR)与维甲酸X受体(retinoid X receptor,RXR)形成的异源二聚体,不同类型的二聚体对于研究EDCs转录活性的生理学相关性具有重要意义。基于经济合作与发展组织(Organization for Economic Co-operation and Development,OECD)报告的参考化学品研究发现,相比于配受体结合活性,二聚活性与转录活性之间有着更好的相关关系。本文从EDCs介导的核受体二聚化转录机制、二聚化与转录活性间的关系以及二聚化研究方法三方面,总结EDCs对核受体二聚化的影响,以期为深入理解EDCs的分子作用机制,推进化合物的内分泌干扰风险评估提供参考。
