In the classical natural product extraction and separation process, it is tedious and requires large amounts of reagents and time. In this study, an efficient coaxial liquid centrifugal oil-water-oil triple-liquid-phase system with a simple structure and convenient operation was successfully constructed and used to extract flavonoids from Platycladi Cacumen. The results showed that the coaxial liquid centrifugal platform constructed in this study had good stability and 6 ml was the minimum volume of the middle phase for 1000 rpm to stabilize the system. Besides, it was easy to repeat the operation: the relative standard deviations of the extraction yields of flavonoids and sugar in six parallel operations were all less than 10%. Moreover, it was only one-tenth of the time required for this method as traditional liquid-liquid extraction while reducing the use of volatile organic reagents. Finally, the new method was more selective than the traditional method for the extraction of flavonoids. Therefore, this study provides a possibility for the coaxial liquid centrifugal platform to be used in multi-liquid phase systems to achieve the simultaneous extraction of different parts of natural products by different liquid phases. It is expected to provide a reliable reference for further expansion of small-scale experimental operations to industrial production. 相似文献
Conventional cancer treatments such as chemotherapy, radiotherapy, or combination of these two result in side effects, which lower the quality of life of the patients. To overcome problems with these methods, altering the drug properties by conjugating them to carrier polymers has emerged. Such polymeric carriers also hold the potential to make tumor cells more sensitive to radiation therapy. Herein, poly(p‐phenylene) (PPP) polymer with poly(ethylene glycol) (PEG) chains and primary amino groups (PPP‐NH2‐g‐PEG) is synthesized and conjugated with anticancer drug Doxorubicin (DOX). pH dependent drug release experiments are performed at pH 5.3 and pH 7.4, respectively. Cell viability studies on human cervix adenocarcinoma cells show that lower doses of DOX inhibit cell proliferation when conjugated with nontoxic doses of PPP‐NH2‐g‐PEG polymer. Additionally, PPP‐NH2‐g‐PEG/Cys/DOX bioconjugate significantly increases radiosensitive properties of DOX. It is possible to use lower doses of DOX when conjugated to PPP‐NH2‐g‐PEG in combination with radiotherapy.
Nafion® impregnated Solupor®, microporous UHMWPE film, (N-PE), Nafion®117 (N117) and a membrane prepared using a DE2020 Nafion® dispersion (DE2020) were characterized with respect to their swelling degree (SD), methanol cross-over, proton conductivity and DMFC performance at various methanol concentrations in order to understand the effect of impregnation of an ion-conductive polymer membrane to the fuel cell performance. 相似文献
The IR spectra of 5-chloro-10-oxa-3-thia-tricyclo[5.2.1.0(1,5)]dec-8-ene-3,3-dioxide (COTDO) has been recorded in the region 4000-525cm(-1). The optimized molecular geometry, frequency and intensity of the vibrational bands of COTDO in the ground state has been calculated using the Hartree-Fock and density functional using Becke's three-parameter hybrid method with the Lee, Yang, and Parr correlation functional methods with 6-31G(d,p) and 6-311G(d,p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental IR spectra. The calculated geometrical parameters and harmonic vibrations are predicted in a very good agreement with the experimental data. The theoretical vibrational spectra of the title compound were interpreted by means of potential energy distributions (PEDs) using VEDA 4 program. With the help of this modern technique we were able to complete the assignment of the vibrational spectra of the title compound. 相似文献
Ethyl imidate hydrochlorides 1 were prepared by passing HCl gas through solutions of substituted benzyl cyanides and absolute ethanol. Ethoxycarbonylhydrazones 2 were synthesized from the reaction of compounds 1 with ethyl carbazate. Treatment of 2 with hydrazine hydrate leads to the formation of substituted 4-amino-4,5-dihydro-1H-1,2,4-triazole-5-ones 3. Isatin and 5-chloroisatin were added to 3 to form Schiff bases 4 and N-Mannich bases 5 of these compounds were synthesized by reacting with formaldehyde and piperidine. Their chemical structures were confirmed by means of IR, (1)H- and (13)C-NMR data and by elemental analysis. 相似文献
New electron-deficient and soluble indenofluorene-based and bisindenofluorene-based ladder-type building blocks embedding carbonyl and dicyanovinylene functionalities were synthesized, and their optical and electrochemical properties were characterized. These derivatives exhibit optical band gaps of 1.83 to 2.44 eV and low LUMO energies of -3.24 to -4.30 eV, representing a promising new building block class for n-type polymeric electronic materials. 相似文献
Synchrotron diffraction with a micrometer-sized X-ray beam permits the efficient characterization of micrometer-sized samples,
even in time-resolved experiments, which is important because often the amount of sample available is small and/or the sample
is expensive. In this context, we will present acoustic levitation as a useful sample handling method for small solid and
liquid samples, which are suspended in a gaseous environment (air) by means of a stationary ultrasonic field. A study of agglomeration
and crystallization processes in situ was performed by continuously increasing the concentration of the samples by evaporating
the solvent. Absorption and contamination processes on the sample container walls were suppressed strongly by this procedure,
and parasitic scattering such as that observed when using glass capillaries was also absent. The samples investigated were
either dissolved or dispersed in water droplets with diameters in the range of 1 micrometer to 2 millimeters. Initial results
from time-resolved synchrotron small- and wide-angle X-ray scattering measurements of ascorbic acid, acetylsalicylic acid,
apoferritin, and colloidal gold are presented. 相似文献
An ultrasonic trap (acoustic levitator) was used as an analytical tool to allow container-free handling of proteins in small sample volumes. This trap was combined for the first time with synchrotron small-angle X-ray scattering (SAXS) for structure analysis of biological macromolecules in a solution. The microfocus beamline at BESSY was used as a source of intense X-ray radiation. Apoferritin (APO) was used as a model protein, and its aggregation behavior in a levitator was followed from a diluted solution to the solid state. Different stages of APO agglomeration were observed without solid container walls, which may influence aggregation behavior and produce a parasitic scattering background. Starting with a volume of 5 microL we analyzed the concentration dependence of APO structure factors in the range from 5 to 1,200 mg/mL (solid protein). The solution was stirred automatically due to convection inside the droplet caused by the ultrasonic field. SAXS data recording of APO was performed in time intervals of 60 s during an aggregation experiment of 30 to 60 min. 相似文献
A new surface based on the natural clay mineral sepiolite and a single-walled carbon nanotubes-modified graphite electrode was developed for the electrochemical detection of DNA, and also for anticancer drug-DNA interactions. 相似文献