以葡萄糖为碳源,聚乙二醇-200（PEG-200）为分散剂和表面修饰剂,采用水热法制备了具有良好水溶性的荧光碳点（CDs）。以CDs为荧光探针,在p H 5.72的Britton-Robinson（B-R）缓冲溶液中,镍离子可使CDs的荧光显著猝灭,据此建立了一种测定...以葡萄糖为碳源,聚乙二醇-200（PEG-200）为分散剂和表面修饰剂,采用水热法制备了具有良好水溶性的荧光碳点（CDs）。以CDs为荧光探针,在p H 5.72的Britton-Robinson（B-R）缓冲溶液中,镍离子可使CDs的荧光显著猝灭,据此建立了一种测定镍离子的荧光光度新方法。结果表明,体系的最大激发波长为350 nm,最大发射波长为435 nm;在最佳实验条件下,镍离子浓度在3.0~80μmol/L范围内与CDs的相对荧光强度呈良好的线性关系,其线性回归方程为ΔF=1.009＋0.031 0 c（μmol/L）,相关系数（r）为0.998 3,检出限为0.13μmol/L。方法应用于环境水样中痕量镍的测定,测定结果与原子吸收光谱法相符。该方法的加标回收率为98.1%~103.5%,相对标准偏差（RSD）小于2%。展开更多
A facile one-pot synthesis of 2-aminothiazoles has been carried in PEG-400 as a greener medium at room temperature.This method avoids the use of lachrymatric a-bromoketones as well as the volatile,toxic organic solvents.
Effect of 24-epibrassinolide and 28-homobrassinolide on the germination and seedling growth of radish (Raphanus sativus) subjected to water stress being imposed by 15% (w/v) polyethylene glycol (equivalent to -2.95 ba...Effect of 24-epibrassinolide and 28-homobrassinolide on the germination and seedling growth of radish (Raphanus sativus) subjected to water stress being imposed by 15% (w/v) polyethylene glycol (equivalent to -2.95 bars of osmotic pressure) was studied. Brassinosteroids supplementation reduced the inhibitory effect of water stress on seed germination and seedling growth. The growth stimulation in radish seedlings by brassinosteroids under desiccation stress was associated with elevated levels of nucleic acids and soluble proteins and lowered activities of RNase. The mitigation of osmotic stress imposed by PEG was associated with increased scavenging of reactive oxygen species as reflected in elevated activities of superoxide dismutase, catalase and ascorbate peroxidase. Brassinosteroids also enhanced the accumulation of the osmolyte free proline in radish seedlings challenged with drought stress. The two brassinosteroids also maintained membrane integrity under water deficiency conditions as indicated by lowered lipid peroxidation reflecting in reduced MDA content. The results of present study demonstrate the protective role of brassinosteroids against PEG imposed water stress in radish seedlings.展开更多
Extraction behavior of chlorpromazine hydrochloride (CPZ) and procaine hydro- chloride (PCN) in the system described in the title was studied. Research shows that the extraction efficiency of CPZ can amount to 96% by...Extraction behavior of chlorpromazine hydrochloride (CPZ) and procaine hydro- chloride (PCN) in the system described in the title was studied. Research shows that the extraction efficiency of CPZ can amount to 96% by twice extraction, while that of PCN is 77%. This system produces the distribution coefficients (KD) of 12.3 and 2.6 respectively for CPZ and PCN. Extraction mechanism is deduced according to ultraviolet and molecular fluorescence spectra variation of the drugs in the system studied.展开更多
文摘A facile one-pot synthesis of 2-aminothiazoles has been carried in PEG-400 as a greener medium at room temperature.This method avoids the use of lachrymatric a-bromoketones as well as the volatile,toxic organic solvents.
文摘Effect of 24-epibrassinolide and 28-homobrassinolide on the germination and seedling growth of radish (Raphanus sativus) subjected to water stress being imposed by 15% (w/v) polyethylene glycol (equivalent to -2.95 bars of osmotic pressure) was studied. Brassinosteroids supplementation reduced the inhibitory effect of water stress on seed germination and seedling growth. The growth stimulation in radish seedlings by brassinosteroids under desiccation stress was associated with elevated levels of nucleic acids and soluble proteins and lowered activities of RNase. The mitigation of osmotic stress imposed by PEG was associated with increased scavenging of reactive oxygen species as reflected in elevated activities of superoxide dismutase, catalase and ascorbate peroxidase. Brassinosteroids also enhanced the accumulation of the osmolyte free proline in radish seedlings challenged with drought stress. The two brassinosteroids also maintained membrane integrity under water deficiency conditions as indicated by lowered lipid peroxidation reflecting in reduced MDA content. The results of present study demonstrate the protective role of brassinosteroids against PEG imposed water stress in radish seedlings.
文摘Extraction behavior of chlorpromazine hydrochloride (CPZ) and procaine hydro- chloride (PCN) in the system described in the title was studied. Research shows that the extraction efficiency of CPZ can amount to 96% by twice extraction, while that of PCN is 77%. This system produces the distribution coefficients (KD) of 12.3 and 2.6 respectively for CPZ and PCN. Extraction mechanism is deduced according to ultraviolet and molecular fluorescence spectra variation of the drugs in the system studied.
