Novel β-cyclodextrin modified quantum dots as fluorescent probes for polycyclic aromatic hydrocarbons （PAHs）

Water-soluble CdSe/ZnS quantum dots （QDs） were prepared via a simple sonochemical procedure using β-cyclodextrin （CD） as surface coating agent. The QDs displayed a sensitive emission enhancement for anthracene over other related polycyclic aromatic hydrocarbons, and the detection limit was around 1.6 × 10^-8 mol/L.     

Effect of PLGA as a polymeric emulsifier on preparation of hydrophilic protein-loaded solid lipid nanoparticles

Most proteins are hydrophilic and poorly encapsulated into the hydrophobic matrix of solid lipid nanoparticles (SLN). To solve this problem, poly (lactic-co-glycolic acid) (PLGA) was utilized as a lipophilic polymeric emulsifier to prepare hydrophilic protein-loaded SLN by w/o/w double emulsion and solvent evaporation techniques. Hydrogenated castor oil (HCO) was used as a lipid matrix and bovine serum albumin (BSA), lysozyme and insulin were used as model proteins to investigate the effect of PLGA on the formulation of the SLN. The results showed that PLGA was essential for the primary w/o emulsification. In addition, the stability of the w/o emulsion, the encapsulation efficiency and loading capacity of the nanoparticles were enhanced with the increase of PLGA concentration. Furthermore, increasing PLGA concentration decreased zeta potential significantly but had no influence on particle size of the SLN. In vitro release study showed that PLGA significantly affected the initial burst release, i.e. the higher the content of PLGA, the lower the burst release. The released proteins maintained their integrity and bioactivity as confirmed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and biological assay. These results demonstrated that PLGA was an effective emulsifier for the preparation of hydrophilic protein-loaded SLN.     

Effects of CO2 laser pretreatment on drought stress resistance in wheat

In order to determine the role of laser in drought stress resistance of spring wheat (Triticum aestivum L.), seed embryos were exposed to CO2 laser radiation for 0min, 1min, 3min and 5min, respectively, and when the seedlings were 12 days old they were treated with 10% (w/v) PEG6000 solution for 10 days. Changes in the concentration of malondialdehyde (MDA), hydrogen peroxide (H2O2), glutathione (GSH), ascorbate (AsA), oxidized glutathione (GSSG), carotenoid, zeaxanthin, the production rate of superoxide radical (O2(-)), the activities of ascorbate peroxidase (APX), peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GP), glutathione-S-transferase (GST) and the growth parameters of seedlings (plant height, leaf area and dry weight) were measured to test the effects of laser pretreatment. The results showed that suitable laser pretreatment of embryos enhanced drought stress resistance in wheat seedlings by decreasing the concentration of MDA and H2O2, GSSG, the production rate of O2(-), leaf area and increasing the activities of APX, GST, GP and POD and AsA, carotenoid and zeaxanthin concentration. It is suggested that those changes in MDA, O2(-) H2O2, anti-oxidative enzymes and anti-oxidative compounds were responsible for the increase in drought stress resistance observed in the experiments. The results also showed that the laser had a long-term positive physiological effect on the growth of drought stress seedlings. This is the first investigation reporting the use of CO2 laser pretreatment to enhance drought stress resistance of spring wheat.     

Preparation, characterization and biocompatibility of poly(ethylene glycol)-poly(n-butyl cyanoacrylate) nanocapsules with oil core via miniemulsion polymerization

A new type of nanocapsules with an oil core, coated by poly(ethylene glycol) (PEG) was designed. The loading efficiency and the biocompatibility of the polymeric nanocapsules were evaluated when it was used as a carrier for hydrophobic agent paclitaxel. The nanocapsules were synthesized through miniemulsion polymerization of butylcyanoacrylate (BCA) with PEG as initiator. The particle size and zeta potential of nanocapsules were influenced by the PEG content in the polymerization system. Fourier transform infrared (FTIR) spectra and ¹H NMR demonstrated the chemical coupling between PEG and poly(butylcyanoacrylate) (PBCA). Thermal characteristics of the copolymer were investigated by differential scanning calorimetry (DSC). The encapsulation efficiency increased concurrently with the increase of the PEG content in the system. The hemolytic assay and the cytotoxicity measurement showed that the PEG coating could significantly reduce the hemolytic potential and cytotoxicity of the nanocapsules. The results showed that the PEG-PBCA nanocapsules could be an effective carrier for hydrophobic agents.     

镝掺杂LaPO4拉曼光谱变化规律的探讨

采用水热法和后续热处理合成出单斜相LaPO4以及LaPO4:Dy3+,通过XRD对样品进行物相分析,结果表明:所得样品为LaPO4,且XRD图谱及拉曼光谱中峰位的偏移表明Dy的存在,即Dy被掺杂到LaPO4基质中。通过研究用Dy对LaPO4进行不同量掺杂后其拉曼光谱的变化规律,进而找出用Dy对LaPO4进行不同量掺杂后其内部结构的变化规律。结果显示,用Dy对LaPO4进行不同量掺杂后,随着掺杂比例的增大,晶格畸变程度先上升后下降,且在镧镝物质的量比例为1∶0.06时对基体晶格结构影响最大。     

Epoxidation reaction of perfluoroalkenes with tert-amine N-oxide

Straight-chain aliphatic terr-amine N-oxides were found to be useful oxidizing agent for epoxidation of tri- and tetra-substituted perfluoroalkenes under mild conditions in high yields.The process for epoxidation by employing tri-n-butylamine N-oxide gave the best result in the reagent survey.     

β‐Diketiminatoytterbium aryloxides: synthesis,structural characterization,and catalytic activity for addition of amines to carbodiimides

The steric effect of an aryloxido group on the synthesis and molecular structures of ytterbium aryloxides supported by β‐diketiminato ligand L (L = [N(2,6‐Me₂C₆H₃)C(Me)]₂CH^?) is reported. Reactions of β‐diketiminatoytterbium dichloride, LYbCl₂(THF)₂, with NaOAr¹ in THF (Ar¹ = [2,6‐^tBu₂‐4‐MeC₆H₂], THF = tetrahydrofuran) at 60°C gave the corresponding ytterbium complexes LYb(OAr¹)Cl(THF) ( 1 ) and LYb(OAr¹)₂ (1), depending on the molar ratio of dichloride to sodium aryloxide, respectively, while the same reactions with NaOAr² and NaOAr³ (Ar² = [2,6‐ⁱPr₂C₆H₃], Ar³ = [2,6‐Me₂C₆H₃]) in 1:1 or 1:2 molar ratio in THF afforded only bisaryloxide complexes LYb(OAr²)₂(THF) (1) and LYb(OAr³)₂(THF) ( 4 ) in good yields, respectively. Complexes 1 , 2 , 3 , 4 were fully characterized, including X‐ray crystal structure analyses. All the complexes are efficient pre‐catalysts for the catalytic addition of amines to carbodiimides giving guanidines. Copyright © 2013 John Wiley & Sons, Ltd.     

Urinary d‐lactate levels reflect renal function in aristolochic acid‐induced nephropathy in mice

Urinary d ‐lactate is highly correlated to diabetic nephropathy – a progressive kidney disease in renal glomeruli. In this study, we used a C3H/3e mouse model to investigate the relationship between urinary d ‐lactate and aristolochic acid nephropathy where the glomerular structure is not affected. The nephropathy was induced using intravenous injections of aristolochic acid at a dosage of 10 mg/kg per day for 5 days and was characterized biochemically and histologically. The urinary excretions of proteins, N‐acetyl‐β‐d ‐glucosaminidase and serum creatinine were determined and connected to histological conventional findings. Urinary d ‐lactate was analyzed using column‐switching high‐performance liquid chromatography with fluorescence detection. The results showed a remarkable increase of urinary markers, including of urinary proteins and N‐acetyl‐β‐d ‐glucosaminidase, and the histological examination confirmed a diagnosis of acute tubule necrosis. The ratio of d ‐lactate to creatinine in the urine of aristolochic acid‐treated mice was approximately 36 times greater than that of the mice in the control group (p < 0.05). The ratios for the two groups of mice were 311.00 ± 71.70 and 8.60 ± 1.80 µmol/mmol creatinine, respectively. These data confirm in vivo that urinary d ‐lactate reflects renal injury conditions in aristolochic acid‐treated mice and may be a marker for the assessment of nephropathy. Copyright © 2013 John Wiley & Sons, Ltd.