A porous organic polymer named FC-POP was facilely synthesized with extraordinary porosity and excellent stability. Further covalent incorporation of various amines including single amine group, multi-amine groups of ...A porous organic polymer named FC-POP was facilely synthesized with extraordinary porosity and excellent stability. Further covalent incorporation of various amines including single amine group, multi-amine groups of diethylenediamine （DETA）, and poly-amine groups of polyethylenimine （PEI） to the network gave rise to task-specific modification of the microenvironments to make them more suitable for CO2 capture. As a result, significant boost of CO2 adsorption capacity of 4.5 mmol/g （for FC-POP-CH2DETA, 273 K, 1 bar） and the CO2/N2 selectivity of 736.1 （for FC- POP-CH2PEI） were observed after the post-synthesis amine modifications. Furthermore, these materials can be regener- ated in elevated temperature under vacuum without apparent loss of CO2 adsorption capacity.展开更多
AIM:To study the molecular mechanism of laterally spreading tumor (LST), a cell line [Laterally Spreading Tumor-Rectum 1 (LST-R1)] was derived and the characteristics of this cell line were investigated. METHODS:A new...AIM:To study the molecular mechanism of laterally spreading tumor (LST), a cell line [Laterally Spreading Tumor-Rectum 1 (LST-R1)] was derived and the characteristics of this cell line were investigated. METHODS:A new cell line (LST-R1) originated from laterally spreading tumor was established. Properties of the cell line were characterized using scanning and transmission electron microscopy, immunohistochemistry method, cytogenetic analysis and nude mice xenograft experiments. In vitro invasion assay, cDNA microarray and Western blotting were used to compare the difference between the LST-R1 and other colorectal cancer cell lines derived from prudent colon cancer. RESULTS:Our study demonstrated that both epithelial special antigen (ESA) and cytokeratin-20 (CK20) were expressed in LST-R1. The cells presented microvilli and tight junction with large nuclei. The karyotypic analysis showed hyperdiploid features with structural chromosome aberrations. The in vivo tumorigenicity was also demonstrated in nude mice xenograft experiments. The invasion assay suggested this cell line has a higher invasive ability. cDNA microarray and Western blotting show the loss of the expression of E-cadherin in LST-R1 cells.CONCLUSION:We established and characterized a colorectal cancer cell line, LST-R1 and LST-R1 has an obvious malignant tendency, which maybe partially attributed to the changes of the expression of some adhesion molecules, such as E-cadherin. It is also a versatile tool for exploring the original and progressive mechanisms of laterally spreading tumor and the early colon cancer genesis.展开更多
Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of /3-naphthalenesulfonic acid (NSA) and sulfuric acid from their solution at 25C onto weakly basic re...Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of /3-naphthalenesulfonic acid (NSA) and sulfuric acid from their solution at 25C onto weakly basic resin D301R. Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA. The data of single-solute adsorption were fitted to the Langmuir model and the Preundlich adsorption model. The ideal adsorbed solution theory (IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria. The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA, respectively, yields the favorable representation of the bisolute competitive adsorption behavior.展开更多
The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）...The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）°, V = 776.2（2） A^3, C6H16CoN2O4S4, Mr = 367.38, Z = 2, De = 1.572 g/cm^3, F（000） = 378 and μ（MoKa） = 1.646 mm^-1. The structure was refined to R= 0.0232 and wR = 0.0645 for 1241 observed reflections with I 〉 2σ（I）. In the title complex, each Co（II） atom is octahedrally coordinated by four O atoms from two DMSO ligands and two water molecules as well as two N atoms from SCN^- ions. The title molecules are connected to each other through intermolecular hydrogen bonds to form a 1-D structure extended by eight-membered Co2O4H2 rings.展开更多
OBJECTIVE CD4^＋CD25^＋ T regulatory （Treg） cells are a population of T cells which suppress an overactive immune system. CCR4 is a chemokine receptor involved in the recruitment of lymphocytes. Nasopharyngeal carci...OBJECTIVE CD4^＋CD25^＋ T regulatory （Treg） cells are a population of T cells which suppress an overactive immune system. CCR4 is a chemokine receptor involved in the recruitment of lymphocytes. Nasopharyngeal carcinoma （NPC） is resistant to immunosurveillance, owing to the increased number of tumor-infiltrating Treg cells which are recruited to the tumor bv CCR4.展开更多
In this study,two different samples were obtained from Küre Copper factory.It was determined that the samples contain:the sample of K.C.F.(Küre Copper Factory),0.70%Cu and 0.5%Co.This sample was firstly grou...In this study,two different samples were obtained from Küre Copper factory.It was determined that the samples contain:the sample of K.C.F.(Küre Copper Factory),0.70%Cu and 0.5%Co.This sample was firstly grounded at-100 mesh dimension.Flotation was done according to previously obtained optimum flotation conditions.The flotation yield of Cu and Co in concentrate phase was found to be low by collective flotation.Even when the samples were grounded at-160 mesh,no change was observed in the flotation result.Especially,Co could not float under the flotation conditions of the non-sulfurized samples.There,a new flotation method was applied which was not applied until now.For this aim,the samples were firstly sulphurised under the steam of H2S+H2O.By this method,the amount of Cu and Co in the samples get rich.According to the obtained results,the optimum reactions for flotation and sulphurization were determined.In the first sulphurization conditions for the sample of K.C.F.,the yield of flotation for the Co and Co were found to be 98.27%and 68.07%,respectively.The results indicate that Cu can be floated at low yield in the original samples.On the other hand,Co cannot float under these conditions.展开更多
Nb-based, perovskite-type oxynitrides ANb(O,N)_(3)(A = Sr, Ba) have been significantly attractive semiconductor materials for photoelectrochemical(PEC) water splitting due to their absorption abilities of intensive-vi...Nb-based, perovskite-type oxynitrides ANb(O,N)_(3)(A = Sr, Ba) have been significantly attractive semiconductor materials for photoelectrochemical(PEC) water splitting due to their absorption abilities of intensive-visible-light. However, PEC activities of these perovskites are relatively low due to reduction of Nb species during nitridation leading to the generation of anion defects and impurity phases.Herein, we propose nitridation of A-rich, layered perovskite A_(5)Nb_(4)O_(15) as starting oxides for general synthesis of photoactive ANbO_(2)N. These layered perovskite A_(5)Nb_(4)O_(15) were completely transformed to single phase perovskite-type ANbO_(2)N by nitridation. Wavelength onsets of light absorption were observed at 700 nm for SrNbO_(2)N and at 740 nm for BaNbO_(2)N. According to X-ray photoelectron spectroscopy results,excess Lewis base A species significantly suppressed the generation of reduced species such as Nb^(4+) and Nb^(3+)during nitridation, although it led to an amorphous surface of the as-prepared oxynitride.Subsequent annealing in Ar largely enhanced surface crystallinity of ANbO_(2)N. As a result, Co(OH)_(x)/ANbO_(2)N/FTO photoanodes, prepared by loading Co(OH)_(x) electrocatalyst, showed high photocurrent density of 1.6(A = Sr) and 2.4 m A cm^(-2)(A = Ba) at 1.23 VRHEunder AM 1.5 G simulated sunlight. These results demonstrate that A-rich layered perovskite A_(5)Nb_(4)O_(15)are effective starting precursors for preparing lowdefective ANbO_(2)N, thus improving PEC water splitting activity.展开更多
The NMR spectra revealed that the calixarene frame of 1, 3-disubstituted calix[4]arenes beating optically active groups is asymmetric, even without the formation of a sub-ring. This inherent chirality arises from the ...The NMR spectra revealed that the calixarene frame of 1, 3-disubstituted calix[4]arenes beating optically active groups is asymmetric, even without the formation of a sub-ring. This inherent chirality arises from the interaction of the two chiral groups, which hinder the substituents＇ free rotation. Thus, these chiral calix[4]arenes display good chiral recognition ability.展开更多
Electrocarboxylation ofbenzalacetone was studied in the presence of an atmospheric pressure of CO2 The only carboxylic product obtained was α-phenyl levulinic acid in a one-compartment electrochemical cell equipped w...Electrocarboxylation ofbenzalacetone was studied in the presence of an atmospheric pressure of CO2 The only carboxylic product obtained was α-phenyl levulinic acid in a one-compartment electrochemical cell equipped with a Mg sacrificial anode at the controlled potential conditions. Influences of the solvents, the electrolytes, the cathode materials, the electrolysis potentials, the concentrations of substrate and the temperatures were studied to improve the yield. The maximal yield is 69% in MeCN-0.1 mol/L TEABF4 on Stainless steel-Mg under a controlled potential of-1.6 V vs.Ag/AgI until 2 F/mol of charge had passed through the cell at 0 ℃.展开更多
Seawater photoelectrolysis is showing huge potential in green energy conversion field,yet it is still a formidable challenge to develop one catalyst that can drive the electrolysis reaction stably,economically and eff...Seawater photoelectrolysis is showing huge potential in green energy conversion field,yet it is still a formidable challenge to develop one catalyst that can drive the electrolysis reaction stably,economically and efficiently.Motivated by this point,the inorganic–organic hybridization strategy is proposed to insitu construct one hierarchical electrode via concurrent electroless plating and polymerization,which assures the growth of boron-modulated nickel–cobalt oxyhydroxide nanoballs and photosensitive polyaniline nanochains on the self-supporting Ti-based foil(B-Co Ni OOH/PANI@TiO_(2)/Ti).Upon inducing photoelectric effect(PEE),the designed target electrode delivers overpotentials as low as 196 and 398 mV at 100 mA cm^(-2)for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),respectively,corresponding to an activity enhancement by about 15%as compared to those without PEE.Inspiringly,when served as bifunctional electrocatalysts for overall seawater electrolysis,it can stably maintain at 200 mA cm^(-2)with negligible decay over 72 h.Further analysis reveals that the exceptional catalytic performance can be credit to the B-CoNiOOH,polyaniline(PANI)and TiO_(2)subunit coupling-induced physically and chemically synergistic catalysis effect such as admirable composition stability,photoelectric function and adhesion capability.The finding in this contribution may trigger much more broad interest to the novel hybrid catalysts consisting of photosensitive polymer and transition metal-based electrocatalysts.展开更多
The aim of the study is to assess the occurrence of fluoride in the groundwater of Kaltungo area and environs. Consumption of high fluoride waters clearly manifests in the majority inhabitant of the area in form of de...The aim of the study is to assess the occurrence of fluoride in the groundwater of Kaltungo area and environs. Consumption of high fluoride waters clearly manifests in the majority inhabitant of the area in form of dental fluorosis especially in the majority of the populace. Thirty groundwater samples were collected from hand-dug wells and boreholes using standard method and were analyzed to determine the fluoride level. The results revealed that the Fluoride in the waters ranges from 0.8 to 1.94 mg/l with a mean value of 1.65 mg/l. No clear variations in fluoride content have been observed in both the borehole samples and those from the hand-dug wells. Ca-Mg-HCO3 and Ca-Mg-Cl are the two major water types obtained in the area, which have a good association with fluoride. Negative correlation is observed between fluoride and temperature, fluoride and magnesium, fluoride and potassium and poor correlation is observed between fluoride and chloride, fluoride and nitrate, fluoride and phosphates which rules out the possibility of anthropogenic source of the fluoride in the waters. Positive correlation between fluoride and iron, indicates that the presence of fluoride in the water is as a result of dissolution of biotite within the host rock (Basalt).展开更多
Over the past few decades,N-sulfonyl hydrazones have been recognized as alternative precursors for hazardous diazo compounds in organic synthesis,allowing for diverse innovative and original chemical transformations t...Over the past few decades,N-sulfonyl hydrazones have been recognized as alternative precursors for hazardous diazo compounds in organic synthesis,allowing for diverse innovative and original chemical transformations that were otherwise difficult to achieve.This critical review summarizes the major advancements in the carbene chemistry of N-sulfonyl hydrazones.The contents of this review are organized based on research conducted by leading scientists who have made significant contributions to this field.The individual carbene transfer reactions and their mechanisms,as well as the potential applications in the synthesis of natural products and complex bioactive molecules,are thoroughly discussed.展开更多
α-Olefins as aliphatic terminal alkenes could be obtained easily from numerous contemporary synthetic reactions as well as petro-chemical industry,and also found in natural products.Compared to the alkenes attaching ...α-Olefins as aliphatic terminal alkenes could be obtained easily from numerous contemporary synthetic reactions as well as petro-chemical industry,and also found in natural products.Compared to the alkenes attaching the directing groups or activating group,the catalytic asymmetric reaction of unactivated terminal alkenes presents great challenges due to the weak electron effect and small steric hindrance effect.This review mainly summarizes the latest progress of the asymmetric reaction of unactivated terminal olefins since 2016.展开更多
A greener and more convenient alternative to traditional methods for the generation of thiyl radical as hydrogen atom transfer(HAT)catalyst is developed,using molecular oxygen to oxidize thiol without the need for che...A greener and more convenient alternative to traditional methods for the generation of thiyl radical as hydrogen atom transfer(HAT)catalyst is developed,using molecular oxygen to oxidize thiol without the need for chemical initiators or light irradiation.The thiol/oxygen catalysis enables selective and efficient difunctionalization of borane.展开更多
Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis.Here,we introduce the development of a visible-light catalytic direct reduction coupling reaction between α-CF_(3)...Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis.Here,we introduce the development of a visible-light catalytic direct reduction coupling reaction between α-CF_(3)-alkyl bromides and alkynyl bromides to access valuable organic frameworks.Our research confirms the excellent compatibility of this reaction with various functional groups,which could be used to modify the substrate with biologically active molecular fragments.Mechanistic investigations,including control experiments,fluorescence quenching studies,and light-switching experiments,have provided insights into the reaction mechanism.This study paves the way for the application of visible-light catalysis in diverse synthetic transformations,offering a sustainable and efficient approach to organic synthesis.展开更多
Sogatella furcifera （Hovarth） is a major rice pest with sexual dimorphism. The objective of the current research was to monitor differentially cytosine methylation at CCGG sequences in male and female adults of S. f...Sogatella furcifera （Hovarth） is a major rice pest with sexual dimorphism. The objective of the current research was to monitor differentially cytosine methylation at CCGG sequences in male and female adults of S. furcifera to determine the association between gene methylation and sexual phenotypes using methylation-sensitive representa- tional difference analysis. After the second subtractive hybridization, four differentially methylated DNA bands were obtained and sequenced. Ten different fragments were found. One fragment from the positive hybridization was 120 bp, and highly similar to the tram- track genes from Nasonia vitripennis. Another fragment from the reverse hybridization was 414 bp, and homologous to the 28S rRNA gene of S. furcifera with a similarity rate as high as 99%. We also discussed how DNA methylation of tramtrack and 28S rRNA genes produced effects on sexual differentiation and development. These results provide potential evidence that DNA methylation of some genes may be related to sexual phenotype variations in S.furcifera and will facilitate future studies on the epigenetic mechanisms of insect sexual dimorphism.展开更多
What is the most favorite and original chemistry developed in your researchgroup?I hope it's always the next one.How do you get into this specific field?Could you please share some experiences with ourreaders?Natu...What is the most favorite and original chemistry developed in your researchgroup?I hope it's always the next one.How do you get into this specific field?Could you please share some experiences with ourreaders?Nature provides many astonishing catalytic machineries for building up molecular complexity and harnessing energy in the most efficient ways.Nature's recipe for catalysis serves as a starting point to develop new catalyst for synthetic and energy chemistry.展开更多
The synthesis of stable open-shell hydrocarbon system comprising of pentagon defects and zigzag edges remains unexplored,which can be considered as model compounds for unraveling the spin-localized states in graphene ...The synthesis of stable open-shell hydrocarbon system comprising of pentagon defects and zigzag edges remains unexplored,which can be considered as model compounds for unraveling the spin-localized states in graphene edges.With concise synthetic approaches,twoπ-extended fluorenyl radicals were synthesized and isolated in their crystalline state.X-ray crystallographic analysis and studies on the magnetic,optical and electrochemical properties of neutral and charged species have revealed an interesting edge-dependence of the spin/charge distribution,that is,the spin and charge distribution shifted from the pentagon defects to the zigzag edges with the elongation of conjugation.Such phenomenon was unprecedented for hydrocarbon radicals and can be rationalized by the recovery of Clar Sextets in the dominant resonance structures.Remarkably,one of the radicals exhibited exceptional stability in air-saturated solutions with the half-life time up to 260 d,thus providing opportunities for the applications as electronic materials.展开更多
With N,N′ bis(benzimidazol 2 yl methyl)amine as the ligand, a novel Cu(II) dinuclear complex was synthesized as a mimetic compound of superoxide dismutase (SOD). The complex was characterized with element ana...With N,N′ bis(benzimidazol 2 yl methyl)amine as the ligand, a novel Cu(II) dinuclear complex was synthesized as a mimetic compound of superoxide dismutase (SOD). The complex was characterized with element analysis, UV and IR spectra. The crystal structure was determined by using X ray diffraction analysis. The crystal structure shows that Cu(II) and its coordinated atoms construct distorted octahedron configuration with oxygen atoms of (ClO - 4) s in the axial directions. The coordinated cations are linked by (ClO - 4) s to form nonplanar sheets. All sheets are linked together into three dimensional network by the intermolecular hydrogen bonds. The result of the activity assay indicates that the complex does have certain biological activity.展开更多
文摘A porous organic polymer named FC-POP was facilely synthesized with extraordinary porosity and excellent stability. Further covalent incorporation of various amines including single amine group, multi-amine groups of diethylenediamine （DETA）, and poly-amine groups of polyethylenimine （PEI） to the network gave rise to task-specific modification of the microenvironments to make them more suitable for CO2 capture. As a result, significant boost of CO2 adsorption capacity of 4.5 mmol/g （for FC-POP-CH2DETA, 273 K, 1 bar） and the CO2/N2 selectivity of 736.1 （for FC- POP-CH2PEI） were observed after the post-synthesis amine modifications. Furthermore, these materials can be regener- ated in elevated temperature under vacuum without apparent loss of CO2 adsorption capacity.
基金The Research Fund for the Doctoral Program of Higher Education, No. 20069981008
文摘AIM:To study the molecular mechanism of laterally spreading tumor (LST), a cell line [Laterally Spreading Tumor-Rectum 1 (LST-R1)] was derived and the characteristics of this cell line were investigated. METHODS:A new cell line (LST-R1) originated from laterally spreading tumor was established. Properties of the cell line were characterized using scanning and transmission electron microscopy, immunohistochemistry method, cytogenetic analysis and nude mice xenograft experiments. In vitro invasion assay, cDNA microarray and Western blotting were used to compare the difference between the LST-R1 and other colorectal cancer cell lines derived from prudent colon cancer. RESULTS:Our study demonstrated that both epithelial special antigen (ESA) and cytokeratin-20 (CK20) were expressed in LST-R1. The cells presented microvilli and tight junction with large nuclei. The karyotypic analysis showed hyperdiploid features with structural chromosome aberrations. The in vivo tumorigenicity was also demonstrated in nude mice xenograft experiments. The invasion assay suggested this cell line has a higher invasive ability. cDNA microarray and Western blotting show the loss of the expression of E-cadherin in LST-R1 cells.CONCLUSION:We established and characterized a colorectal cancer cell line, LST-R1 and LST-R1 has an obvious malignant tendency, which maybe partially attributed to the changes of the expression of some adhesion molecules, such as E-cadherin. It is also a versatile tool for exploring the original and progressive mechanisms of laterally spreading tumor and the early colon cancer genesis.
基金US Army Research Office (YW) the Drexel &Hahnemann University Synergy Grant (YW&PIL)+3 种基金 the Commonwealth of Pennsylvania through agrant to the Nanotechnology Institute of Southeastern Pennsylvania (YW PIL &AGM) National Institutes of Health ( DE09848 to YW) and NASA Graduate Student Research Fellowship (NAG9-1380)
基金Supported by the Natural Science Foundation of Jilin Province (No. 990337).
文摘Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of /3-naphthalenesulfonic acid (NSA) and sulfuric acid from their solution at 25C onto weakly basic resin D301R. Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA. The data of single-solute adsorption were fitted to the Langmuir model and the Preundlich adsorption model. The ideal adsorbed solution theory (IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria. The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA, respectively, yields the favorable representation of the bisolute competitive adsorption behavior.
基金This work was supported by the National Natural Science Foundation of China (No. 50572040)
文摘The title complex Co（DMSO）2（H2O）2（SCN）2 has been prepared and structurally characterized. It crystallizes in monoclinic, space group P21/n with a= 5.1981（9）, b = 11.944（2）, c = 12.646（2） A,β = 98.686（2）°, V = 776.2（2） A^3, C6H16CoN2O4S4, Mr = 367.38, Z = 2, De = 1.572 g/cm^3, F（000） = 378 and μ（MoKa） = 1.646 mm^-1. The structure was refined to R= 0.0232 and wR = 0.0645 for 1241 observed reflections with I 〉 2σ（I）. In the title complex, each Co（II） atom is octahedrally coordinated by four O atoms from two DMSO ligands and two water molecules as well as two N atoms from SCN^- ions. The title molecules are connected to each other through intermolecular hydrogen bonds to form a 1-D structure extended by eight-membered Co2O4H2 rings.
基金the National Natural Science Foundation of China
文摘OBJECTIVE CD4^＋CD25^＋ T regulatory （Treg） cells are a population of T cells which suppress an overactive immune system. CCR4 is a chemokine receptor involved in the recruitment of lymphocytes. Nasopharyngeal carcinoma （NPC） is resistant to immunosurveillance, owing to the increased number of tumor-infiltrating Treg cells which are recruited to the tumor bv CCR4.
文摘In this study,two different samples were obtained from Küre Copper factory.It was determined that the samples contain:the sample of K.C.F.(Küre Copper Factory),0.70%Cu and 0.5%Co.This sample was firstly grounded at-100 mesh dimension.Flotation was done according to previously obtained optimum flotation conditions.The flotation yield of Cu and Co in concentrate phase was found to be low by collective flotation.Even when the samples were grounded at-160 mesh,no change was observed in the flotation result.Especially,Co could not float under the flotation conditions of the non-sulfurized samples.There,a new flotation method was applied which was not applied until now.For this aim,the samples were firstly sulphurised under the steam of H2S+H2O.By this method,the amount of Cu and Co in the samples get rich.According to the obtained results,the optimum reactions for flotation and sulphurization were determined.In the first sulphurization conditions for the sample of K.C.F.,the yield of flotation for the Co and Co were found to be 98.27%and 68.07%,respectively.The results indicate that Cu can be floated at low yield in the original samples.On the other hand,Co cannot float under these conditions.
基金financially supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government(MSIT)(2020R1C1C1006373 and 2021M3I3A1084818)。
文摘Nb-based, perovskite-type oxynitrides ANb(O,N)_(3)(A = Sr, Ba) have been significantly attractive semiconductor materials for photoelectrochemical(PEC) water splitting due to their absorption abilities of intensive-visible-light. However, PEC activities of these perovskites are relatively low due to reduction of Nb species during nitridation leading to the generation of anion defects and impurity phases.Herein, we propose nitridation of A-rich, layered perovskite A_(5)Nb_(4)O_(15) as starting oxides for general synthesis of photoactive ANbO_(2)N. These layered perovskite A_(5)Nb_(4)O_(15) were completely transformed to single phase perovskite-type ANbO_(2)N by nitridation. Wavelength onsets of light absorption were observed at 700 nm for SrNbO_(2)N and at 740 nm for BaNbO_(2)N. According to X-ray photoelectron spectroscopy results,excess Lewis base A species significantly suppressed the generation of reduced species such as Nb^(4+) and Nb^(3+)during nitridation, although it led to an amorphous surface of the as-prepared oxynitride.Subsequent annealing in Ar largely enhanced surface crystallinity of ANbO_(2)N. As a result, Co(OH)_(x)/ANbO_(2)N/FTO photoanodes, prepared by loading Co(OH)_(x) electrocatalyst, showed high photocurrent density of 1.6(A = Sr) and 2.4 m A cm^(-2)(A = Ba) at 1.23 VRHEunder AM 1.5 G simulated sunlight. These results demonstrate that A-rich layered perovskite A_(5)Nb_(4)O_(15)are effective starting precursors for preparing lowdefective ANbO_(2)N, thus improving PEC water splitting activity.
基金support of the National Natural Science Foundation of China(No.20072007).
文摘The NMR spectra revealed that the calixarene frame of 1, 3-disubstituted calix[4]arenes beating optically active groups is asymmetric, even without the formation of a sub-ring. This inherent chirality arises from the interaction of the two chiral groups, which hinder the substituents＇ free rotation. Thus, these chiral calix[4]arenes display good chiral recognition ability.
基金Acknowlegement： This work was supported by National Nature Science Foundation of China （No. 20573037）, the Natural Science Foundation of Shanghai （No. 05JC470） and Shanghai Leading Academic Discipline Project （No. B409）.
文摘Electrocarboxylation ofbenzalacetone was studied in the presence of an atmospheric pressure of CO2 The only carboxylic product obtained was α-phenyl levulinic acid in a one-compartment electrochemical cell equipped with a Mg sacrificial anode at the controlled potential conditions. Influences of the solvents, the electrolytes, the cathode materials, the electrolysis potentials, the concentrations of substrate and the temperatures were studied to improve the yield. The maximal yield is 69% in MeCN-0.1 mol/L TEABF4 on Stainless steel-Mg under a controlled potential of-1.6 V vs.Ag/AgI until 2 F/mol of charge had passed through the cell at 0 ℃.
基金supported by the National Natural Science Foundation of China(22109098)the Shanghai Sailing Program(20YF1432300)+4 种基金the Shanghai Engineering Research Center for Food Rapid Detection(19DZ2251300)the Natural Science Foundation of Jiangsu Province(BK20210735)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(21KJB430043)the Collaborative Innovation Center of Suzhou Nano Science&Technology,the 111 Projectthe Suzhou Key Laboratory of Functional Nano&Soft Materials。
文摘Seawater photoelectrolysis is showing huge potential in green energy conversion field,yet it is still a formidable challenge to develop one catalyst that can drive the electrolysis reaction stably,economically and efficiently.Motivated by this point,the inorganic–organic hybridization strategy is proposed to insitu construct one hierarchical electrode via concurrent electroless plating and polymerization,which assures the growth of boron-modulated nickel–cobalt oxyhydroxide nanoballs and photosensitive polyaniline nanochains on the self-supporting Ti-based foil(B-Co Ni OOH/PANI@TiO_(2)/Ti).Upon inducing photoelectric effect(PEE),the designed target electrode delivers overpotentials as low as 196 and 398 mV at 100 mA cm^(-2)for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),respectively,corresponding to an activity enhancement by about 15%as compared to those without PEE.Inspiringly,when served as bifunctional electrocatalysts for overall seawater electrolysis,it can stably maintain at 200 mA cm^(-2)with negligible decay over 72 h.Further analysis reveals that the exceptional catalytic performance can be credit to the B-CoNiOOH,polyaniline(PANI)and TiO_(2)subunit coupling-induced physically and chemically synergistic catalysis effect such as admirable composition stability,photoelectric function and adhesion capability.The finding in this contribution may trigger much more broad interest to the novel hybrid catalysts consisting of photosensitive polymer and transition metal-based electrocatalysts.
文摘The aim of the study is to assess the occurrence of fluoride in the groundwater of Kaltungo area and environs. Consumption of high fluoride waters clearly manifests in the majority inhabitant of the area in form of dental fluorosis especially in the majority of the populace. Thirty groundwater samples were collected from hand-dug wells and boreholes using standard method and were analyzed to determine the fluoride level. The results revealed that the Fluoride in the waters ranges from 0.8 to 1.94 mg/l with a mean value of 1.65 mg/l. No clear variations in fluoride content have been observed in both the borehole samples and those from the hand-dug wells. Ca-Mg-HCO3 and Ca-Mg-Cl are the two major water types obtained in the area, which have a good association with fluoride. Negative correlation is observed between fluoride and temperature, fluoride and magnesium, fluoride and potassium and poor correlation is observed between fluoride and chloride, fluoride and nitrate, fluoride and phosphates which rules out the possibility of anthropogenic source of the fluoride in the waters. Positive correlation between fluoride and iron, indicates that the presence of fluoride in the water is as a result of dissolution of biotite within the host rock (Basalt).
基金the financial support from the National Natural Science Foundation of China(22331004)。
文摘Over the past few decades,N-sulfonyl hydrazones have been recognized as alternative precursors for hazardous diazo compounds in organic synthesis,allowing for diverse innovative and original chemical transformations that were otherwise difficult to achieve.This critical review summarizes the major advancements in the carbene chemistry of N-sulfonyl hydrazones.The contents of this review are organized based on research conducted by leading scientists who have made significant contributions to this field.The individual carbene transfer reactions and their mechanisms,as well as the potential applications in the synthesis of natural products and complex bioactive molecules,are thoroughly discussed.
基金supports were provided by National Key R&D Program of China (2021YFA1500200 and 2021YFF0701600)NSFC (22271249)the Fundamental Research Funds for the Central Universities (226-2022-00224 and 226-2023-00115).
文摘α-Olefins as aliphatic terminal alkenes could be obtained easily from numerous contemporary synthetic reactions as well as petro-chemical industry,and also found in natural products.Compared to the alkenes attaching the directing groups or activating group,the catalytic asymmetric reaction of unactivated terminal alkenes presents great challenges due to the weak electron effect and small steric hindrance effect.This review mainly summarizes the latest progress of the asymmetric reaction of unactivated terminal olefins since 2016.
基金supported by research start-up fund(Project No.4933621)from the Chinese University of Hong Kong.Mr.Weixuan Sun is thanked for checking the experimental procedure。
文摘A greener and more convenient alternative to traditional methods for the generation of thiyl radical as hydrogen atom transfer(HAT)catalyst is developed,using molecular oxygen to oxidize thiol without the need for chemical initiators or light irradiation.The thiol/oxygen catalysis enables selective and efficient difunctionalization of borane.
基金support was from Tianjin University(2024XJD-0062)the National Natural Science Foundation of China(No.22371203).
文摘Traditional reduction coupling reactions of two bromides typically rely on transition metal catalysis.Here,we introduce the development of a visible-light catalytic direct reduction coupling reaction between α-CF_(3)-alkyl bromides and alkynyl bromides to access valuable organic frameworks.Our research confirms the excellent compatibility of this reaction with various functional groups,which could be used to modify the substrate with biologically active molecular fragments.Mechanistic investigations,including control experiments,fluorescence quenching studies,and light-switching experiments,have provided insights into the reaction mechanism.This study paves the way for the application of visible-light catalysis in diverse synthetic transformations,offering a sustainable and efficient approach to organic synthesis.
基金This research was supported by the National Nat- ural Science Foundation of China （31171844） and Natural Science Foundation of Guangdong Province （$2011010001353）. We are very grateful to Dr. Min Zhang and Mrs. Wen-Jing Wu for technical assistance.
文摘Sogatella furcifera （Hovarth） is a major rice pest with sexual dimorphism. The objective of the current research was to monitor differentially cytosine methylation at CCGG sequences in male and female adults of S. furcifera to determine the association between gene methylation and sexual phenotypes using methylation-sensitive representa- tional difference analysis. After the second subtractive hybridization, four differentially methylated DNA bands were obtained and sequenced. Ten different fragments were found. One fragment from the positive hybridization was 120 bp, and highly similar to the tram- track genes from Nasonia vitripennis. Another fragment from the reverse hybridization was 414 bp, and homologous to the 28S rRNA gene of S. furcifera with a similarity rate as high as 99%. We also discussed how DNA methylation of tramtrack and 28S rRNA genes produced effects on sexual differentiation and development. These results provide potential evidence that DNA methylation of some genes may be related to sexual phenotype variations in S.furcifera and will facilitate future studies on the epigenetic mechanisms of insect sexual dimorphism.
基金references,for their significant contributions to this project and the Natural Science Foundation of China(21861132003,91956000 and 22031006)Tsinghua University Initiative Scientific Research Program for financial support.
文摘What is the most favorite and original chemistry developed in your researchgroup?I hope it's always the next one.How do you get into this specific field?Could you please share some experiences with ourreaders?Nature provides many astonishing catalytic machineries for building up molecular complexity and harnessing energy in the most efficient ways.Nature's recipe for catalysis serves as a starting point to develop new catalyst for synthetic and energy chemistry.
基金support from the National Natural Science Foundation of China(Grant No.21971187)the Natural ScienceFoundationof Tianjin(19JCJQJC62700)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘The synthesis of stable open-shell hydrocarbon system comprising of pentagon defects and zigzag edges remains unexplored,which can be considered as model compounds for unraveling the spin-localized states in graphene edges.With concise synthetic approaches,twoπ-extended fluorenyl radicals were synthesized and isolated in their crystalline state.X-ray crystallographic analysis and studies on the magnetic,optical and electrochemical properties of neutral and charged species have revealed an interesting edge-dependence of the spin/charge distribution,that is,the spin and charge distribution shifted from the pentagon defects to the zigzag edges with the elongation of conjugation.Such phenomenon was unprecedented for hydrocarbon radicals and can be rationalized by the recovery of Clar Sextets in the dominant resonance structures.Remarkably,one of the radicals exhibited exceptional stability in air-saturated solutions with the half-life time up to 260 d,thus providing opportunities for the applications as electronic materials.
基金NationalNaturalScienceFoundationofTianjinEducationCommittee (No .972 0 2 )
文摘With N,N′ bis(benzimidazol 2 yl methyl)amine as the ligand, a novel Cu(II) dinuclear complex was synthesized as a mimetic compound of superoxide dismutase (SOD). The complex was characterized with element analysis, UV and IR spectra. The crystal structure was determined by using X ray diffraction analysis. The crystal structure shows that Cu(II) and its coordinated atoms construct distorted octahedron configuration with oxygen atoms of (ClO - 4) s in the axial directions. The coordinated cations are linked by (ClO - 4) s to form nonplanar sheets. All sheets are linked together into three dimensional network by the intermolecular hydrogen bonds. The result of the activity assay indicates that the complex does have certain biological activity.
