Search Results
You are looking at 21 - 30 of 32 items for
- Author or Editor: Wei Yang x
- Refine by Access: All Content x
Abstract
Nitrogen-doped titanium dioxide (TiO2) nanotube arrays were synthesized by anodization in ethylene glycol electrolyte and annealing in ammonia at 500 °C. Detailed analysis showed that the nitrogen-doped titania nanotubes were pure anatase of ordered structure, with a crystallite size of 8.5 nm. The doping nitrogen atoms were induced on the interstitial sites and substitutional sites and the ratio of oxygen vacancies increased to 27.15 %, resulting in an add-on peak in the absorption spectrum and extended the absorption from 387 to 618 nm. The photocatalytic activity of the nitrogen-doped TiO2 nanotubes was evaluated by photocatalytic degradation of methyl blue under visible light irradiation. Significant improvement of photocatalytic activity under visible light irradiation was observed. We assumed the nitrogen doping induced the effect produced by nitrogen atoms, Ti3+ cations and oxygen vacancies and the size effect of the TiO2 crystallite should be responsible for the effective photocatalytic activity.
Abstract
In this study, α-phase nucleating agent (NA) 1,3:2,4-bis(3,4-dimethylbenzylidene) sorbitol (DMDBS), β-phase rare earth NA (WBG), and their compound NAs were introduced into isotactic polypropylene (iPP) matrix, respectively. Crystallization kinetics and subsequent melting behavior of the nucleated iPPs were comparatively studied by differential scanning calorimetry (DSC) under both isothermal and nonisothermal conditions. For the isothermal crystallization process, it is found that the Avrami model successfully described the crystallization kinetics. The active energy of nonisothermal crystallization of iPP was determined by the Kissinger method and showed that the addition of nucleating agents increased the activation energy. Melting behavior and crystalline structure of the nucleated iPPs are dependent on the nature of NAs and crystallization conditions. Higher proportion of β-phase can be obtained at higher content of β-nucleating agent and lower crystallization temperature or lower cooling rate.
Abstract
In this paper, 3-amino-1-hydroxypropylidene-1,1-bisphosphonate(APB), a amidobisphophonate was synthesized and labeled with the α-emitter 211At by an indirect method using N-succinimidyl 5-(tributylstannyl)-3-pyridinecarboxylate (SPC) as a bi-functional linker, and the conjugated amidobisphophonate (211At-SAPC-APB) was preliminarily evaluated in vitro and in vivo by comparison with free astatide (211At−) and 99mTc-MDP. 3-amino-1-hydroxypropylidene-1,1-bisphosphonate(APB) was prepared using β-alanine as the starting material. With SPC bi-functional linker, APB was conjugated with 211At in a labeling yield of 80–90% with radiochemical purity of more than 99%. The conjugated amidobisphophonate (211At-SAPC-APB) exhibited considerable stability in vitro, in that the radiochemical purity of 211At-SAPC-APB was still more than 98% in 0.1 mol/L PBS (pH 7.6) or in fetal calf serum, even stayed for 24 h at room temperature (RT). Biodistribution of 211At-SAPC-APB was investigated in NIH strain mice by I.V injection. The results showed that 211At-SAPC-APB could rapidly locate in shank, with the maximum uptake of 23.70 ± 2.29% I.D/g at 6 h, earlier than that of 99mTc-MDP at 12 h, and stayed in the bone for long time. Moreover, 211At-SAPC-APB uptake in some key organs or tissues, especially in thyriod, stomach, lung and spleen, was much less than that of free astatide (211At−), implying that 211At-SAPC-APB was constantly stable in vivo as well as in vitro. These results indicated that 211At-SAPC-APB will be a suitable candidate for the targeted radiotherapy of bone metastases and should be further investigated.
Abstract
The mass production and extensive applications of nanomaterials may have potential negative effects on health of human beings. Research on the in vivo behavior of fullerene, the most representative nanomaterial, just begins. In order to investigate the in vivo behavior of fullerene derivative and to explore new biomedical application of fullerene, fullerol, C60(OH)20, was labeled by 99mTc(CO)3. The labeling conditions were optimized. Gamma counter and SPECT were used to access the in vivo biological behavior of the complex. Results showed that the complex was stable in mice body. The complex was delivered to all tissues rapidly except for brain. A significant percentage of total activity was retained in 3 h, particularly in the liver, spleen, lung, thyroid, kidney and bladder, which indicated the mononuclear phagocyte system (MPS) took an important part in clearing the complex and the complex was mainly excreted through urine. The low radioactivity of all tissues and organs in 24 h indicated that the cleanup speed was rapid. The high uptake and rapid cleanup speed of the complex in important organs hinted fullerene could be used as carrier for in vivo radionuclide decorporation agents.
Abstract
With 2,3,5,6-tetrafluorophenyl 3-(nodo-carboranyl) propionate (TCP) as a new potential bi-functional linker, bovine serum albumin (BSA) was conjugated with 211At, and the conjugated model protein (211At-TCP-BSA) was preliminarily evaluated in vitro and in vivo by comparison with 211At-SAB-BSA and 211At-SAPC-BSA, which conjugated with 211At via aryl derivatives ATE (N-succinimidyl-3-(tri-n-butylstannyl) benzoate) or SPC (N-succinimidyl 5-(tributylstannyl)-3-pyridinecarboxylate). The radiolabeled intermediate 211At-TCP was coupled to BSA in yields ranging from 35 to 45% with radiochemical purity of more than 98%. The conjugated 211At-TCP-BSA exhibited considerable stability in vitro in 0.1 mol/L PBS (pH 7.6) at room temperature (RT), similar to 211At-SAPC-BSA and 211At-SAB-BSA. Biodistribution of the 211At conjugated protein was investigated in NIH strain mice by I.V injection. The results showed that 211At-TCP-BSA was constantly stable in vivo as well as in vitro, but more stable than 211At-SAPC-BSA and 211At-SAB-BSA. These results implied that radioastatinated carboranes based on B–At bonds are higher stability than radioastatinated aryl derivatives based on C–At to in vivo deastatination. In other word, TCP should be a promising bi-functional linker for 211At conjugation of proteins or antibodies.
Partial abortion of gametes possessing S-5 j in S-5 i / S-5 j genotype at locus S-5 is responsible for hybrid sterility between indica and japonica subspecies in rice ( Oryza sativa L.), while a single wide compatibility (WC) allele S-5 n can restore normal hybrid fertility between the two groups. In this study, Pei’ai 64S, one of the most popular WC line widely used for subspecific hybrid rice breeding program in South China was studied for location of its S-5 locus. Twenty SSR (Simple Sequence Repeat) markers derived from Cornell SSR linkage map and 9 developed using sequences from GenBank database were employed to perform bulked segregant analysis of the mapping population derived from a three-way cross (Pei’ai 64S/T8//Akihikari) to tag fine location of the hybrid sterility locus, S-5 . This S-5 locus was mapped on chromosome 6 approximately 0.2 cM from GXR6 and RM276 SSR markers. This tight linkage of the markers and the S-5 locus would be very useful for efficient marker-assisted selection for WC varieties and for map-based cloning of the gene.
Abstract
A sensitive and rapid method using HPLC-MS/MS was developed for the determination of eight glucocorticoids residues in chicken muscle simultaneously by Turbo Flow. The eight glucocorticoids were prednisone, prednisolone, hydrocortisone, methylprednisolone, dexamethasone, betamethasone, beclomethasone and fludrocortisones. Samples were extracted with ethyl acetate and on-line cleaned up through a Turbo Flow solid-phase extraction column without time-consuming pretreatment before HPLC-MS/MS analysis. Sample pretreatment conditions, Turbo Flow conditions and mass spectral parameters were optimized and obtained eight glucocorticoids calibration curves. These curves showed good linearity over the concentration from 0.2 μg/kg to 50 μg/kg with an average recovery from 71.63% to 117.36%. This method could be applied on real samples and provided simple, rapid, sensitive and highly selective analysis, which made it feasible to be adopted in food inspection organizations or carry out quantitative analysis for other banned substance.
Abstract
A reliable LC-MS/MS method for the determination of five bioactive constituents (bilobalide, BLL; ginkgolide A, GLA; ginkgolide B, GLB; ginkgolide C, GLC; rutin) of Ginkgo biloba leaf extracts (GBE) in rat plasma was established, fully validated and applied to an intragastric pharmacokinetic study of a preparation of GBE in rat. Samples were extracted with ethyl acetate. C18 column was selected as analytical column in this method. Mobile phase was water with 0.01% formic acid and acetonitrile. Quantification was performed in negative multiple-reaction monitoring mode. Matrix instability of terpene lactones was noticed and hydrochloric acid was used as a stabilizer. This method showed good precision and accuracy, recovery was reproducible and matrix effect was negligible. Among four terpene lactones, BLL had the highest exposure and the shortest terminal half-life, GLA and GLB had lower exposure and longer terminal half-life, the exposure of GLC was lowest and its terminal half-life was the maximum, and all of them showed rapid absorption. This study provides a reference for determination of terpene lactones and flavonol glycoside prototypes in GBE and offers pharmacokinetic data of flavonol glycoside prototype in GBE.
Abstract
SZJ-1207 is a natural product extracted from Stephanotis mucronata (Blanco) Merr which has significant antidepressant effects in various depression mouse models, without obvious acute toxicity or sedative-hypnotic side effects. The aim of this study was to preliminarily clarify the pharmacokinetic characteristics of SZJ-1207 in rats after a single intragastric and intravenous administration. In this study, sensitive and reliable UPLC-MS/MS quantification methods were established and then successfully applied to the pharmacokinetic study of SZJ-1207 in rats. The linear range of SZJ-1207 were 0.5–400 ng mL−1 in plasma, feaces, bile and 20–4,000 ng mL−1 in urine, respectively (r > 0.99). All methods met the requirements of ICH M10. The results of pharmaconetic study showed that Cmax, AUC(0-t) and AUC(0-∞) had linear relationships with the administered doses in the range of 0.5–4.5 mg kg−1. There was a significant gender difference in the AUC (0-t) of 0.5 and 1.5 mg kg−1 and Cmax of 1.5 mg kg−1 after ig (P < 0.05). The excretion rates of SZJ-1207 were 8.46 ± 4.82% in feces, 1.89 ± 1.08% in urine, and 0.179 ± 0.118% in bile. The oral absolute bioavailability of SZJ-1207 was calculated as 64.64%.
While in situ TLC/FTIR technique has tremendous potential in the analysis of complex mixtures, the conventional stationary phase, such as silica gel, used for TLC/FTIR analysis, has strong absorption in IR region and thus brings about severe interference in the obtained FTIR spectra of the separated samples. In this work, we propose to use lanthanum fluoride fine particles as a new stationary phase of a TLC plate. The average size of LaF3 particles is around 100 nm. FTIR spectrum of the LaF3 particles has no interfering absorption. Preliminary TLC experiments show that mixtures of rhodamine B and methylene blue mixture can be successfully separated by this new TLC plate using LaF3 fine particles as a stationary phase. Methylene blue and rhodamine B from separated spot can be clearly detected by using in situ FTIR spectra.
