醋酸甲羟孕酮与β-环糊精包络作用的光谱研究及应用

用紫外吸收、荧光光谱法对水溶液中β－环糊精（β－ＣＤ）与醋酸甲羟孕酮（ＭＡ）主客体包络物的光谱行为进行了研究．利用改进的Ｂｅｎｅｓｉ－Ｈｉｌｄｅｂｒａｎｄ法测定了包络物的形成常数，初步探讨了某些水溶性一元醇的引入对该包络物形成及荧光性质的影响，并提出了测定ＭＡ的高灵敏度荧光光度新方法，方法的最低检出限为８．９×１０－９ｍｏｌ·Ｌ－１．用该法测定样品中ＭＡ的结果令人满意，回收率为９７．９％～１０１．７％，平均回收率为９９．９％（ｎ＝５）     

Facile preparation of nano-g-C3N4/UiO-66-NH2 composite as sorbent for high-efficient extraction and preconcentration of food colorants prior to HPLC analysis

In this work,the nano-g-C₃N₄/Ui O-66-NH₂composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C₃N₄/Ui O-66-NH₂composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatogra...     

Bottom-contact poly(3,3'-didodecylquaterthiophene) thin-film transistors with gold source-drain electrodes modified by alkanethiol monolayers

A series of alkanethiol monolayers (CH 3(CH 2) n-1 SH, n = 4, 6, 8, 10, 12, 14, 16) were used to modify gold source-drain electrode surfaces for bottom-contact poly(3,3'-didodecylquaterthiophene) (PQT-12) thin-film transistors (TFTs). The device mobilities of TFTs were significantly increased from approximately 0.015 cm (2) V (-1) s (-1) for bare electrode TFTs to a maximum of approximately 0.1 cm (2) V (-1) s (-1) for the n = 8 monolayer devices. The mobilities of devices with alkanethiol-modified Au electrodes varied parabolically with alkyl length with values of 0.06, 0.1, and 0.04 cm (2) V (-1) s (-1) at n = 4, 8, and 16, respectively. Atomic force microscopy investigations reveal that alkanethiol electrode surface modifications promote polycrystalline PQT-12 morphologies at electrode/PQT-12 contacts, which probably increase the density of states of the PQT-12 semiconductor at the interfaces. The contact resistance of TFTs is strongly modulated by the surface modification and strongly varies with the alkanethiol chain length. The surface modifications of electrodes appear to significantly improve the charge injection, with consequent substantial improvement in device performance.     

Versatile coordination chemistry towards multifunctional carbon nanotube nanohybrids

Dispersible single-walled carbon nanotubes grafted with poly(4-vinylpyridine), SWNT-PVP, were tested in coordination assays with zinc tetraphenylporphyrin (ZnP). Kinetic and spectroscopic evidence corroborates the successful formation of a SWNT-PVPZnP nanohybrid. Within this SWNT-PVPZnP nanohybrid, static electron-transfer quenching (2.0+/-0.1) x 10(9) s(-1) converts the photoexcited-ZnP chromophore into a radical-ion-pair state with a microsecond lifetime, namely one-electron oxidized-ZnP and reduced-SWNT.     

Quality assessment of Astragali Radix based on pseudo-targeted metabolomics and chemometric approach

Astragali Radix is widely used because of its dual use in medicine and food, and its quality evaluation is of great importance. In this study, a pseudo-targeted metabolomics approach based on scheduled multiple reaction monitoring was developed, and a total of 114 compounds with good linearity, sensitivity, and reproducibility were selected for relative quantification, and the chemical differences between Astragali Radix of different growth patterns were further compared by chemometric analysis. With the help of multivariate and univariate analysis, 26 differential compounds between wild/semi-wild Astragali Radix and cultivated Astragali Radix were determined. Then five marker compounds were screened out by lasso regression, and further verified by systematic clustering, random forest, support vector machine, and logistic regression. In addition, malonyl-substituted flavonoids showed relatively higher content in wild/semi-wild Astragali Radix. Thus, the malonyl substitution was characteristic for flavonoids in wild/semi-wild Astragali Radix. In conclusion, the application of pseudo-targeted metabolomics and various statistical methods could offer multi-dimensional information for the holistic quality evaluation of Astragali Radix.     

Synthesis of Macrocyclic Arsinous Acid Estcrs

MacrocyclicarsinousacidestersareusuallypreparedbycondensationofdichloroalkylarsinesRAsCI,Iwithdidsinthepresenceoforganicalkali].ThemethoddescribedhereinvolvesthetransformationofintermediatefromItohis(dimethylamino)alkylarsineRAs(NMe,),2andthereactionof2withdidsindryTHFtoleadtotheformationoftitlecompounds.2canreactsmoothlywithdidsintheabsenceoforganicalkalitogeneratecorrespondingmacrocyclicarsinousacidesters4anddimethylaminewhichescapesfromthereactingsystemasagasinreflux.Althoughonemoreste…     

Homogenous synthesis of hydroxyethylcellulose in NaOH/urea aqueous solution

Hydroxyethylcellulose (HEC) was synthesized by a fully homogenous method from cellulose in 7.5 wt.-% NaOH/11 wt.-% urea aqueous solutions under mild conditions. HEC samples were characterized with NMR, SEC-LLS, solubility, and viscosity measurements. The MS and DS values of the obtained HEC samples are in the range from 0.54 to 1.44 and 0.45 to 1.14, respectively, and the relative DS values at C-2 and C-6 hydroxyl groups are slightly higher than those at C-3 hydroxyl groups. HEC samples are soluble in water starting from a MS of 0.57 and DS of 0.49, which display high viscosity in aqueous solutions. Moreover, a NaOH/urea aqueous solution is a stable system for cellulose etherification. In this way, we could provide a simple, pollution-free, and homogeneous aqueous solution system for synthesizing cellulose ethers.     

Determination of molindone enantiomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry using macrocyclic antibiotic chiral stationary phases

A sensitive and selective bioanalytical assay was developed and validated for the determination of enantiomeric molindone in human plasma using high-performance liquid chromatography-tandem mass spectrometry along with supported liquid extraction procedures. The chiral separation was evaluated and optimized on macrocyclic antibiotic type chiral stationary phases (CSPs) based on teicoplanin aglycone (Chirobiotic TAG) in polar organic, polar ionic, and reversed-phase mode chromatography, respectively. Complete baseline separation was achieved on a Chirobiotic TAG column under isocratic condition in reversed-phase chromatography. The method validation was conducted using a Chirobiotic TAG column (100 mm x 2.1 mm) over the curve range 0.100-100 ng/ml for each molindone enantiomer using 0.0500 ml of plasma sample. The flow rate was 0.8 ml/min and the total run time was 9 min. Supported liquid extraction in a 96-well plate format was used for sample preparation. Parameters including recovery, matrix effect, linearity, sensitivity, specificity, carryover, precision, accuracy, dilution integrity, and stability were evaluated. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels were RSD 相似文献   

Characterization and biological evaluation of paclitaxel-loaded poly(L-lactic acid) microparticles prepared by supercritical CO2

In this study, paclitaxel loaded poly( L-lactic acid) (PTX-PLLA) microparticles were prepared using solution enhanced dispersion by supercritical CO2(SEDS) technique. This supercritical antisolvent technique offers the advantage of negligible organic solvent residua in the drug loaded microparticles. Scanning electron microscopy (SEM) showed that microparticles exhibited rather spherical shape and small particle size with narrow particle size distribution. X-ray diffraction (XRD) and differential scanning calorimeter (DSC) indicated that PTX was amorphously dispersed in the PLLA matrix. The drug loading and encapsulation efficiency of PTX-PLLA microparticles were 14.33% and 62.68%, respectively. In vitro cytotoxicity evaluation of PTX-PLLA microparticles against nonsmall-cell lung cancer A549 and ovarian cancer SKOV3 cell lines indicated that PTX-PLLA had superior antiproliferation activity against the A549 and SKOV3 cell lines, compared with free PTX formulations. The cellular internalization of fluorescent microparticles was evidenced by fluorescence microscope and further confirmed by transmission electron microscopy (TEM). This was attributed to the efficient intracellular accumulation of PTX via cell phagocytosis and sustained release of PTX from PLLA matrix. The anticancer activity of PTX-PLLA was associated with PTX-induced cell apoptosis such as nuclear aberrations, condensation of chromatin and swelling damage in mitochondria. The cell apoptosis index detected by flow cytometry was higher in PTX-PLLA group than in free PTX. The PTX-PLLA formulation, which was obtained through micronization of PTX and encapsulation of micronized PTX into PLLA simultaneously in the SEDS process, significantly potentiated the anticancer activity of PTX.     

CO adsorption on Ag(100) and Ag/MgO(100)

Theoretical studies of CO adsorption on a two-layer Ag(100) film and on a two-layer Ag film on a MgO(100) support are reported. Ab initio calculations are carried at the configuration interaction level of theory using embedding methods to treat the metal-adsorbate region and the extended ionic solid. The metal overlayer is considered in two different structures: where Ag-Ag distances are equal to the value in the bulk solid, and for a slightly expanded lattice in which the Ag-Ag distances are equal to the O-O distance on the MgO(100) surface. The calculated adsorption energy of Ag(100) on MgO(100) is 0.58 eV per Ag interfacial atom; the Ag-O distance is 2.28 A. A small transfer of electrons from MgO to Ag occurs on deposition of the silver overlayer. CO adsorption at an atop Ag site is found to be the most stable for adsorption on the two-layer Ag film and also for adsorption on Ag deposited on the oxide; CO adsorption energies range from 0.12 to 0.19 eV. The CO adsorption energy is reduced for the Ag/MgO system compared to adsorption on the unsupported metal film thereby providing evidence for a direct electronic effect of the oxide support at the metal overlayer surface. Expansion of the Ag-Ag distance in the two-layer system also reduces the adsorption energy.