Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ a...Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ and LaPO_4∶Eu 3+ were synthesized by in-situ co-precipitation method. X-ray diffraction and scanning electronic micrograph were used to characterize the resultant samples, whose particle size are in the range of micrometer. The emission spectra of Zn_3(PO_4)_2∶Eu 3+ (λ_ ex=245 nm) and LaPO_4∶Eu 3+ (λ_ ex=390 nm) shows that the emission for Eu 3+ in Zn_3(PO_4)_2 is dominated by the 5D_0→7F_1 (592 nm) magnetic-dipole transition,While the dominant emission for Eu 3+ in LaPO_4 is the typical hypersensitive transition 5D_0→7F_2 (618 nm).展开更多
The deposition of amyloid-beta is a pathological hallmark of Alzheimer＇s disease, Amyloid-beta is derived from amyloid precursor protein through sequential proteolytic cleavages by β-secretase （beta-site amyloid pr...The deposition of amyloid-beta is a pathological hallmark of Alzheimer＇s disease, Amyloid-beta is derived from amyloid precursor protein through sequential proteolytic cleavages by β-secretase （beta-site amyloid precursor protein-cleaving enzyme 1） and r-secretase. To further elucidate the roles of beta-site amyloid precursor protein-cleaving enzyme 1 in the development of AIzheimer＇s disease, a yeast two-hybrid system was used to screen a human embryonic brain cDNA library for proteins directly interacting with the intracellular domain of beta-site amyloid precursor protein-cleaving enzyme 1. A potential beta-site amyloid precursor protein-cleaving enzyme 1- interacting protein identified from the positive clones was divalent cation tolerance protein. Immunoprecipitation studies in the neuroblastoma cell line N2a showed that exogenous divalent cation tolerance protein interacts with endogenous beta-site amyloid precursor protein-cleaving enzyme 1. The overexpression of divalent cation tolerance protein did not affect beta-site amyloid precursor protein-cleaving enzyme 1 protein levels, but led to increased amyloid precursor protein levels in N2a/APP695 cells, with a concomitant reduction in the processing product amyloid precursor protein C-terminal fragment, indicating that divalent cation tolerance protein inhibits the processing of amyloid precursor protein. Our experimental findings suggest that divalent cation tolerance protein negatively regulates the function of beta-site amyloid precursor protein-cleaving enzyme 1. Thus, divalent cation tolerance protein could play a protective role in Alzheimer＇s disease.展开更多
采用成核-晶化隔离法制备LiAl-CO_(3)-LDHs晶核,在LDHs晶核晶化的过程中引入葡萄糖分子作为碳源,构筑组成和结构可调的LDHs/C型杂化复合前体。通过高温处理,实现前体的结构拓扑转变及无定形碳组分的去除,得到高比表面积的LiAl复合金属...采用成核-晶化隔离法制备LiAl-CO_(3)-LDHs晶核,在LDHs晶核晶化的过程中引入葡萄糖分子作为碳源,构筑组成和结构可调的LDHs/C型杂化复合前体。通过高温处理,实现前体的结构拓扑转变及无定形碳组分的去除,得到高比表面积的LiAl复合金属氧化物型固体碱催化剂。采用XRD、FT-IR、BET、TEM、SEM、CO_(2)-TPD等表征手段对催化剂的组成、结构、织构性能、表面碱性进行了详细研究,并以苯甲醛和氰基乙酸乙酯间的Knoevenagel缩合反应为探针反应系统地研究了催化剂的碱催化性能。研究结果表明,LDHs/C杂化前体制备过程中葡萄糖与金属离子的摩尔比、水热晶化温度以及焙烧温度是影响催化剂活性的主要因素,晶化温度和焙烧温度的提升不利于碱性位的充分暴露。在150℃的水热晶化温度下,葡萄糖与Al 3+的摩尔比为3时的杂化复合前体经500℃焙烧得到的LiAl-MMO-150-3-500固体催化剂比表面积高达229 m 2·g^(-1),苯酚吸附测得催化剂的总碱量为855μmol·g^(-1),对苯甲醛的转化率高达88.21%。展开更多
文摘Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ and LaPO_4∶Eu 3+ were synthesized by in-situ co-precipitation method. X-ray diffraction and scanning electronic micrograph were used to characterize the resultant samples, whose particle size are in the range of micrometer. The emission spectra of Zn_3(PO_4)_2∶Eu 3+ (λ_ ex=245 nm) and LaPO_4∶Eu 3+ (λ_ ex=390 nm) shows that the emission for Eu 3+ in Zn_3(PO_4)_2 is dominated by the 5D_0→7F_1 (592 nm) magnetic-dipole transition,While the dominant emission for Eu 3+ in LaPO_4 is the typical hypersensitive transition 5D_0→7F_2 (618 nm).
基金supported by the National Natural Science Foundation of China, No. 81171192XMU Basic Training Program of Undergraduate, No. CXB2011019Visiting Scholar Fellowship of Key Laboratory of Ministry of Education for Cell Biology and Tumor Cell Engineering of Xiamen University, No. 201101
文摘The deposition of amyloid-beta is a pathological hallmark of Alzheimer＇s disease, Amyloid-beta is derived from amyloid precursor protein through sequential proteolytic cleavages by β-secretase （beta-site amyloid precursor protein-cleaving enzyme 1） and r-secretase. To further elucidate the roles of beta-site amyloid precursor protein-cleaving enzyme 1 in the development of AIzheimer＇s disease, a yeast two-hybrid system was used to screen a human embryonic brain cDNA library for proteins directly interacting with the intracellular domain of beta-site amyloid precursor protein-cleaving enzyme 1. A potential beta-site amyloid precursor protein-cleaving enzyme 1- interacting protein identified from the positive clones was divalent cation tolerance protein. Immunoprecipitation studies in the neuroblastoma cell line N2a showed that exogenous divalent cation tolerance protein interacts with endogenous beta-site amyloid precursor protein-cleaving enzyme 1. The overexpression of divalent cation tolerance protein did not affect beta-site amyloid precursor protein-cleaving enzyme 1 protein levels, but led to increased amyloid precursor protein levels in N2a/APP695 cells, with a concomitant reduction in the processing product amyloid precursor protein C-terminal fragment, indicating that divalent cation tolerance protein inhibits the processing of amyloid precursor protein. Our experimental findings suggest that divalent cation tolerance protein negatively regulates the function of beta-site amyloid precursor protein-cleaving enzyme 1. Thus, divalent cation tolerance protein could play a protective role in Alzheimer＇s disease.
文摘采用成核-晶化隔离法制备LiAl-CO_(3)-LDHs晶核,在LDHs晶核晶化的过程中引入葡萄糖分子作为碳源,构筑组成和结构可调的LDHs/C型杂化复合前体。通过高温处理,实现前体的结构拓扑转变及无定形碳组分的去除,得到高比表面积的LiAl复合金属氧化物型固体碱催化剂。采用XRD、FT-IR、BET、TEM、SEM、CO_(2)-TPD等表征手段对催化剂的组成、结构、织构性能、表面碱性进行了详细研究,并以苯甲醛和氰基乙酸乙酯间的Knoevenagel缩合反应为探针反应系统地研究了催化剂的碱催化性能。研究结果表明,LDHs/C杂化前体制备过程中葡萄糖与金属离子的摩尔比、水热晶化温度以及焙烧温度是影响催化剂活性的主要因素,晶化温度和焙烧温度的提升不利于碱性位的充分暴露。在150℃的水热晶化温度下,葡萄糖与Al 3+的摩尔比为3时的杂化复合前体经500℃焙烧得到的LiAl-MMO-150-3-500固体催化剂比表面积高达229 m 2·g^(-1),苯酚吸附测得催化剂的总碱量为855μmol·g^(-1),对苯甲醛的转化率高达88.21%。
