Inhibitory Effect of Flavonoid Glycosides from Chlorophytum comosum on Nasopharyngeal Carcinoma 5-8F Cells and Its Mechanism

[Objectives]To study the inhibitory activity of two flavonoid glycosides isolated from Chlorophytum comosum Laxum R.Br on human nasopharyngeal carcinoma(NPC)cell line 5-8F in vitro and its mechanism.[Methods]The flavonoid glycosides were isolated and purified from the ethanol alcoholic extract of the roots of Liliaceae plant Chlorophytum comosum by silica gel column chromatography,macroporous resin column chromatography,Sephadex LH-20,and reverse column chromatography(ODS).The inhibitory activity of flavonoid glycosides on human nasopharyngeal carcinoma cells was analyzed by CCK-8 method,and the potential mechanism was preliminarily analyzed by molecular docking.[Results]Two flavonoid glycosides were identified as isovitexin 2″-0-rhamnoside and 7-2″-di-O-β-glucopyranosylisovitexin.Two flavonoid glycosides showed promising inhibitory effect on human nasopharyngeal carcinoma cell line 5-8F,with IC_(50) values of 24.8 and 27.5μmol/L,respectively.Molecular docking results showed that the potential targets of two flavonoid glycosides include CyclinD1,Bcl-2β-Catenin,ILK,TGF-β,in addition,two glycosides showed higher predicted binding affinity towards CyclinD1,which verifies the cytotoxicity of the two compounds on human nasopharyngeal carcinoma cell line 5-8F in vitro.[Conclusions]Two flavonoid glycosides are the active molecules in Chlorophytum comosum that can inhibit the proliferation of human nasopharyngeal carcinoma cells,and have the potential to be used in the research and development of anti nasopharyngeal carcinoma drugs.

Analysis of the Risk of Water Breakout in the Bottom Plate of High-Intensity Mining of Extra-Thick Coal Seams

In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site monitoring means combining borehole peeping and microseismic monitoring, combined with the theoretical analysis to analyze the danger of water breakout in the bottom plate. The results show that: 1) the theoretically calculated maximum damage depth of the bottom plate is 27.5 m, and its layer is located above the Austrian ash aquifer, which has the danger of water breakout;2) the drill hole peeping at the bottom plate of the working face shows that the depth of the bottom plate fissure development reaches 26 m, and the integrity of the water barrier layer has been damaged, so there is the risk of water breakout;3) for the microseismic monitoring of the anomalous area, the bottom plate of the return air downstream channel occurs in the field with a one-week lag, which shows that microseismic monitoring events may reflect the water breakout of the underground. This shows that the microseismic monitoring events can reflect the changes of the underground flow field, which can provide a reference basis for the early warning of water breakout. The research results can provide reference for the prediction of sudden water hazard.

碳包覆Pd/TiO_(2)光催化产氢协同胺类选择性氧化合成亚胺

负载型金属纳米催化剂由于其优异的光催化性能,被广泛应用于光催化产氢协同胺类氧化偶联合成高附加值亚胺体系。但在反应过程中,金属表面对H原子和亚胺表现出较强的吸附能力,导致了亚胺易于发生自氢化反应而生成仲胺,显著降低了亚胺的选择性。在本文中,我们证实了在Pd/TiO_(2)表面构建超薄碳层(Pd/TiO_(2)@C)是一种解决上述问题的有效策略。在Pd/TiO_(2)表面构筑的超薄碳层可以有效调控H原子和亚胺在其表面的吸附行为,避免了光催化氧化偶联过程中亚胺的自氢化。因此,Pd/TiO_(2)@C光催化剂在光催化产氢协同胺类选择性氧化合成亚胺体系中展现出优异的亚胺选择性。本研究提供了一种便捷有效的策略推动负载型金属纳米催化剂在光催化产氢协同合成高附加值产物体系中的应用。

Phosphorene-Based Heterostructured Photocatalysts

Semiconductor photocatalysis is a potential pathway to solve the problems of global energy shortage and environmental pollution.Black phosphorus(BP)has been widely used in the field of photocatalysis owing to its features of high hole mobility,adjustable bandgap,and wide optical absorption range.Nevertheless,pristine BP still exhibits unsatisfactory photocatalytic activity due to the low separation efficiency of photoinduced charge carriers.In recent years,the construction of heterostructured photocatalysts based on BP has become a research hotspot in photocatalysis with the remarkable improvement of photoexcited charge-separation efficiency.Herein,progress on the design,synthesis,properties,and applications of BP and its corresponding heterostructured photocatalysts is summarized.Furthermore,the photocatalytic applications of BP-based heterostructured photocatalysts in water splitting,pollutant degradation,carbon dioxide reduction,nitrogen fixation,bacterial disinfection,and organic synthesis are reviewed.Opportunities and challenges for the exploration of advanced BP-based heterostructured photocatalysts are presented.This review will promote the development and applications of BP-based heterostructured photocatalysts in energy conversion and environmental remediation.

Molecular pore-wall engineering of mesozeolitic conjugated polymers for photoredox hydrogen production with visible light

A chemical protocol based on molecular engineering of polymeric matrix is developed for the chemical optimization of ordered mesoporous carbon nitride (OMCN) in this study to address the concerns on the serious nanostructure-induced semiconductive defects, in particular the remarkable hypsochromic shift of absorption threshold and the increased excition dissociation energy. Physical characterizations demonstrate that the successful incorporation of 3-aminothiophene-2-carbonitrile (ATCN) aromatic donor in OMCN matrix can efficiently extend the pi-conjugated system, red-shift the optical absorption toward longer wavelengths and promote exciton splitting, thus well overcoming the serious semiconductive defects. In addition, the unique structural benefits of OMCN, such as the well-orientated nanoarchitectures with large specific surface area and uniform nanosized pore, have been well remained in ATCN-modified sample (OMCNA) via adjusting the ATCN/cyanamide molar ratio to minimize the unavoidable matrix disturbance. Hence, an obviously enhanced photocatalytic activity toward H-2 evolution and selective oxidation of alcohols are obtained on optimized OMCNA samples, greatly underlining the advantage of molecular engineering in supporting nanostructured photocatalysts. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

第十七届全国青年催化学术会议专刊前言（英文）

Catalysis occurs when a catalyst forges a new reaction pathway that is unavailable to an uncatalyzed reaction.Catalysis is involved in almost 80%of chemical processes,and important applications include the synthesis of pharmaceutically active ingredients,production of petrochemicals and nitrogen fertilizers,the development of renewable energy and the reduction of pollution emission.In particular,green catalysis is at the heart of industrial and environmental challenges on energy,health,and sustainable development.

Dynamic cooperations between lattice oxygen and oxygen vacancies for photocatalytic ethane dehydrogenation by a self-restoring LaVO_(4)catalyst

Thermocatalytic nonoxidative ethane dehydrogenation(EDH)is a promising strategy for ethene production but suffers from intense energy consumption and poor catalyst durability;exploring technology that permits efficient EDH by solar energy remains a giant challenge.Herein,we present that an oxygen vacancy(O_v)-rich LaVO_(4)(LaVO_(4)-O_v)catalyst is highly active and stable for photocatalytic EDH,through a dynamic lattice oxygen(O_(latt.))and O_(v)co-mediated mechanism.Irradiated by simulated sunlight at mild conditions,LaVO_(4)-O_(v)effectively dehydrogenates undiluted ethane to produce C_(2)H_(4)and CO with a conversion of 2.3%.By loading a small amount of Pt cocatalyst,the evolution and selectivity of C_(2)H_(4)are enhanced to 275μmol h^(-1)g^(-1)and 96.8%.Of note,LaVO_(4)-O_(v)appears nearly no carbon deposition after the reaction.The isotope tracked reactions reveal that the consumed O_(latt.)recuperates by exposing the used catalyst with O_(2),thus establishing a dynamic cycle of O_(latt.)and achieving a facile catalyst regeneration to preserve its intrinsic activity.The refreshed LaVO_(4)-O_(v)exhibits superior reusability and delivers a turnover number of about 305.The O_(v)promotes photo absorption,boosts ethane adsorption/activation,and accelerates charge separation/transfer,thus improving the photocatalytic efficiency.The possible photocatalytic EDH mechanism is proposed,considering the key intermediates predicted by density functional theory(DFT)and monitored by in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS).

Photocatalysis:an overview of recent developments and technological advancements

Photocatalysis,which is the catalyzation of redox reactions via the use of energy obtained from light sources,is a topic that has garnered a lot of attention in recent years as a means of addressing the environmental and economic issues plaguing society today.Of particular interest are photosynthesis can potentially mimic a variety of vital reactions,many of which hold the key to develop sustainable energy economy.In light of this,many of the technological and procedural advancements that have recently occurred in the field are discussed in this review,namely those linked to:(1)photocatalysts made from metal oxides,nitride,and sulfides;(2)photocatalysis via polymeric carbon nitride(PCN);and(3)general advances and mechanistic insights related to TiO2-based catalysts.The challenges and opportunities that have arisen over the past few years are discussed in detail.Basic concepts and experimental procedures which could be useful for eventually overcoming the problems associated with photocatalysis are presented herein.

Metalloporphyrin-based covalent organic frameworks composed of the electron donor-acceptor dyads for visible-light-driven selective CO2 reduction

The visible-light-driven photocatalytic CO2 reduction with high efficiency is highly desirable but challenging.Herein,we present porphyrin-tetraphenylethene-based covalent organic frameworks(MP-TPE-COF,where M=H2,Co and Ni;TPE=4,4′,4″,4?-(ethane-1,1,2,2-tetrayl)tetrabenzaldehyde;COF=covalent organic framework)as ideal platforms for understanding photocatalytic CO2 reduction at molecular level.Experimental and theoretical investigations have demonstrated crucial roles of metalloporphyrin units in selective adsorption,activation and conversion of CO2 as well as in the separation of charge carriers and electron transfer,thus allowing for flexible modulation of photocatalytic activity and selectivity.Co P-TPE-COF exhibits high CO evolution rate of 2,414μmol g-^1 h^-1 with the selectivity of 61%over H2 generation under visible-light irradiation,while Ni P-TPE-COF provides CO evolution rate of 525μmol g^-1 h^-1 and 93%selectivity with superior durability.Moreover,the photocatalytic system is feasible for the simulated flue gas,which provides CO evolution rate of 386μmol g-1 h-1 and selectivity of 77%.This work provides in-depth insight into the structure-activity relationships toward the activation and photoreduction of CO2.

Synthesis of Ferrocene-Modified Carbon Nitride Photocatalysts by Surface Amidation Reaction for Phenol Synthesis

A polymeric Fc-CO-NH-C_(3)N_(4)(Fc-CN)material was synthesized by amidation reaction of ferrocenecarboxylic acid(Fc-COOH)with NH_(2)groups on the surface of mesoporous graphitic carbon nitride(MCN).The properties of the as-synthesized samples were characterized by X-ray diffraction,Fourier transform infrared spectroscopy,UV-Vis diffuse reflectance spectra,N2 adsorption-desorption isotherm,photoluminescence spectroscopy,transmis-sion electron microscopy,electron paramagnetic resonance,(photo)electrochemical measurement and X-ray photo-electron spectroscopy.The resultant catalysts were investigated as heterogeneous catalysts for the selective oxida-tion of benzene to phenol using H_(2)O_(2)as a green oxidant under visible light irradiation.The results reveal that Fc-modified samples can not only extend the visible light absorption,but also accelerate the bulk-to-surface charge transfer and separation via surface dyadic structures,both of which are favorable for phenol production from ben-zene photocatalytic hydroxylation with H_(2)O_(2).Under the optimal conditions,up to 16.9%phenol yield(based on benzene)is obtained by Fc-CN/1.5-5 sample,and the corresponding Fe content is about 0.64 wt%.Furthermore,after the second run,no significant decrease of the activity(in term of TOF)and the selectivity is found in Fc-CN/_(1.0)-5 sample.Combined with the experimental results and Fenton-chemistry,a possible photocatalytic reaction mecha-nism on the hydroxylation of benzene to phenol at neutral medium with visible light is proposed.

Semi-Hydrogenation of Alkynes by a Tandem Photoredox System Free of Noble Metal

The selective hydrogenation reactions play a key role in industrial manufacture of fine chemicals,which mainly rely on noble metal catalysts.Herein,a noble-metal-free hybrid photosystem is established,in which boron carbonitride(BCN)and nickel bis-diphosphine complex(NiP)catalyze cooperatively the semi-hydrogenation of alkynes with high efficiency and excellent selectivity(>99%)under mild reaction conditions.

Roles of Metal-Free Materials in Photoelectrodes for Water Splitting

CONSPECTUS:Photoelectrochemical(PEC)water splitting is an appealing approach to the hydrogen evolution reaction since it converts sunlight in the form of hydrogen fuel,which has the potential to revolutionize the fossil fuel-based energy systems of the modern society.In the last half century,progress has been made with respect to the material,synthesis,and system.Recent developments of multilayered photoelectrodes have made a breakthrough to improve the sunlight conversion efficiency and strengthen the physiochemical stability.The exploration of new materials for the functional layers of photoelectrodes offers a new opportunity for practical application.Among the emerging materials,metal-free species have shown superior properties,such as high stability,sustainability,and renewability.With respect to inorganic materials,their physiochemical properties can be readily regulated,including thermodynamics and kinetics,and thus increasing attention has been devoted.