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891.
Two new compounds, 6'-O-caffeoyl-p-hydroxyacetophenone-4-O-beta-D-glucopyranoside(1) and 6-amino-9-[1-(3,4-dihydroxyphenyl)ethyl]-9H-purine (2) were isolated from the aerial parts of Artemisia capillaris Thunb. The structures were established on the basis of spectral data. 相似文献
892.
A series of novel substituted 1,2,3-benzotriazines based on the structures of vatalanib succinate (PTK787) and vandetanib (ZD6474) were designed and synthesized. The antiproliferative effects of these compounds were tested on microvascular endothelial cells (MVECs) using the MTT assay. Introduction of a methoxy and a 3-chloropropoxy group into the 1,2,3-benzotriazines increased the antiproliferative effects. 4-(3-Chloro-4- fluoroanilino)-7-(3-chloropropoxy)-6-methoxy-1,2,3-benzotriazine (8m) was the most effective compound. It was 4-10 fold more potent than PTK787 in inhibiting the growth of T47D breast cancer cells, DU145 and PC-3 prostate cancer cells, LL/2 murine Lewis lung cancer cells and B16F0 melanoma cells. 相似文献
893.
The corrosion and corrosion inhibition of bulk nanocrystalline ingot iron (BNII) fabricated from conventional polycrystalline
ingot iron (CPII) by severe rolling was studied in 0.5 M H2SO4 solution using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results indicate that
BNII was more susceptible to corrosion in the acidic environment essentially because of an increase in the kinetics of the
anodic reaction. An amino acid cysteine (cys) was employed as a corrosion inhibitor at concentrations of 0.001 and 0.005 M.
Tests in inhibited solutions revealed that cys reduced the corrosion rates of both metal specimens by different mechanisms.
For CPII cys inhibited the cathodic reaction but had a stimulating effect on the anodic process at low concentration and a
trivial effect at higher concentration. For BNII, cys inhibited both the cathodic and the anodic reactions, although the former
effect was more pronounced. Iodide ions improved the inhibitive effect of cys without altering the inhibition mechanism. 相似文献
894.
Xiong XQ Zhao DM Bu PF Liu Y Ren JH Wang J Cheng MS 《Molecules (Basel, Switzerland)》2008,13(8):1822-1839
CoMFA, CoMSIA and eigenvalue analysis (EVA) were performed to study the structural features of 61 diverse dibenzodioxepinone and dibenzodioxocinone analogues to probe cholesteryl ester transfer protein (CETP) inhibitory activity. Three methods yielded statistically significant models upon assessment of cross-validation, bootstrapping, and progressive scrambling. This was further validated by an external set of 13 derivatives. Our results demonstrate that three models have a good interpolation as well as extrapolation. The hydrophobic features were confirmed to contribute significantly to inhibitor potencies, while a pre-oriented hydrogen bond provided by the hydroxyl group at the 3-position indicated a good correlation with previous SAR, and a hydrogen bond acceptor may play a crucial role in CETP inhibition. These derived models may help us to gain a deeper understanding of the binding interaction of these lactone-based compounds and aid in the design of new potent compounds against CETP. 相似文献
895.
The development of tissue engineering scaffolds is of great significance for the repair and regeneration of damaged tissues and organs. Silk fibroin (SF) is a natural protein polymer with good biocompatibility, biodegradability, excellent physical and mechanical properties and processability, making it an ideal universal tissue engineering scaffold material. Nanofibers prepared by electrospinning have attracted extensive attention in the field of tissue engineering due to their excellent mechanical properties, high specific surface area, and similar morphology as to extracellular matrix (ECM). The combination of silk fibroin and electrospinning is a promising strategy for the preparation of tissue engineering scaffolds. In this review, the research progress of electrospun silk fibroin nanofibers in the regeneration of skin, vascular, bone, neural, tendons, cardiac, periodontal, ocular and other tissues is discussed in detail. 相似文献
896.
Ping Wang Yue Wang Ping Li Chen Chen Siman Ma Linxuan Zhao Haibing He Tian Yin Yu Zhang Xing Tang Jingxin Gou 《中国化学快报》2023,34(4):107691-141
Efficient oral delivery of drugs treating brain diseases has long been a challenging topic faced by the drug delivery community. Fortunately, polyester nanoparticles offer certain solutions to this problem. This review article firstly describes the main obstacles faced by oral administered brain targeting, including:(1)instability in the gastrointestinal tract;(2) poor penetration of the intestinal mucosa and epithelium;(3)blood clearance; and(4) restriction by the BBB. Then the key factors infl... 相似文献
897.
《中国化学快报》2023,34(7):107788
Alkaline hydrogen evolution reaction (HER) suffers from a sluggish kinetic, which requires the elaborate catalytic interface and micro-nanoscale architecture engineering of the electrocatalysts to accelerate the water dissociation and hydrogen evolution. Herein, the heterointerface engineering was proposed for promoting the alkaline HER by constructing the highly exposed Ru/RuS2 heterostructures homogeneously distributed on hollow N/S-doped carbon microspheres (Ru/RuS2@h-NSC). Benefited from the synergistic effect of heterointerfacial Ru/RuS2, the high accessibility of the active sites on both inner and outer surface of mesoporous shells and the efficient mass transport, Ru/RuS2@h-NSC affords a remarkable catalytic performance with an overpotential of 26 mV@10 mA/cm2 for alkaline HER, outperforming most of the state-of-the-art catalysts. Further applying Ru/RuS2@h-NSC and its oxidized derivate for the overall alkaline water splitting, the required cell voltage is much lower than that of the commercial Pt/C||RuO2 pair to achieve the same current density. Our study may allow us to guide the design of micro-nanoreactors with optimal catalytic interfaces for promising electrocatalytic applications. 相似文献
898.
Yanfang Shen Tianying Xiong Jianku Shang Ke Yang 《Research on Chemical Intermediates》2008,34(4):353-363
Niobium pentaoxide (Nb2O5) and nitrogen co-doped TiO2 photocatalysts were prepared by mechanical alloying with Nb2O5, TiO2 and urea as raw materials. The pure TiO2 powders of Degussa P25 were chosen as precursor. Chemical and physical properties of the Nb2O5 and N co-doped TiO2 photocatalysts were investigated, including XRD patterns, XPS spectra, DRS spectra, FT-IR spectra and N2 adsorption-desorption isotherms. Experiments on photodegradation of methylene blue (MB) and sulfosalicylic acid (SSA) under
visible light were carried out to evaluate the photoactivities of the prepared samples, and the chemical oxygen demand (COD)
analysis was also conducted as a comparison. 相似文献
899.
Icotinib, 4-[(3-ethynylphenyl)amino]-6,7-benzo-12-crown-4-quinazoline, is a new antitumor agent. The metabolic pathway of icotinib in rats was studied using liquid chromatography/tandem mass spectrometry (LC/MS(n)) analysis. Full scan and selected ion monitoring modes were used to profile the possible metabolites of icotinib in rat urine, feces and bile samples. Four phase I metabolites (M1-M4) and two phase II metabolites (M5, M6) were detected and characterized. Multiple-stage mass spectrometry and nuclear magnetic resonance (NMR) spectrometry were employed to elucidate structures of metabolites. Icotinib was metabolized to open the crown ether ring to form the main phase I metabolites. During metabolism, a reactive metabolite was formed. Using semicarbazide as a trapping agent, an intermediate arising from opening of the crown ether ring was detected as an aldehyde product by LC/MS/MS. These data indicated that ring opening of the crown ether was triggered by hydroxylation at the 8'-position of the ring to form a hemiacetal intermediate, which was further oxidized or reduced. Finally, the metabolic pathway of icotinib in rats was proposed. 相似文献
900.
Song-Hua Gao Ke-Sheng Zhou Ming-Kai Lei Li-Shi Wen 《Plasma Chemistry and Plasma Processing》2008,28(6):715-728
Silicone rubber samples were treated by CF4 capacitively coupled plasma at radio frequency (RF) power of 60, 100 and 200 W for a treatment time up to 20 min under CF4 flow rate of 20 sccm, respectively. Static contact angle, ATR-FTIR and XPS, and AFM were employed to characterize the changes
of surface on hydrophobicity, functional groups, and topography. The results indicate the static contact angle is improved
from 100.7 to 150.2°, and the super-hydrophobic surface, which corresponds to a static contact angle of 150.2°, appears at
RF power of 200 W for a 5 min treatment time. It is suggested that the formation of super-hydrophobic surface is ascribed
to the co-action of the increase of surface roughness created by the ablation reaction of CF4 plasma and the formation of [–SiF
x
(CH3)2−x
–O–]
n
(x = 1, 2) structure produced by the direct attachment of F atoms to Si. 相似文献