A quinine-derived thiourea-catalyzed inter-/intramolecular Michael cycloaddition of chromoneoxindole/benzofuranone synthons with 3-substituted methylenebenzofuranones has been established,which constructed enantiomeri...A quinine-derived thiourea-catalyzed inter-/intramolecular Michael cycloaddition of chromoneoxindole/benzofuranone synthons with 3-substituted methylenebenzofuranones has been established,which constructed enantiomerically pure bispiro[benzofuran-oxindole/benzofuran-chromanone]s bearing five consecutive stereocenters including two spiro quaternary carton centers in good yields(up to 93%) with high diastereoselectivities(up to>20:1 dr) and good enantioselectivities(up to>99% ee).Moreover,this is the first example of bifunctional chromone-benzofuranone synthon directed organocatalytic tandem reaction,and also the first example of the bispiro[benzofuran-oxindole] and bispirobenzofuranone,potentially useful in medicinal chemistry.展开更多
Inter-and intramolecular quenching of zinc phthalocyanine fluorescence by anthraquinone has been studied.The diminutions of fluorescence quantum yield and life-time are due primarily to electron transfer.Apparent elec...Inter-and intramolecular quenching of zinc phthalocyanine fluorescence by anthraquinone has been studied.The diminutions of fluorescence quantum yield and life-time are due primarily to electron transfer.Apparent electron transfer rate constants were calculated depending on the chain length and solvent polarity.展开更多
Hydrocarbons are one of the important fluids within the Earth's crust,and different biotic and abitoic processes can generate hydrocarbon during geological periods.Tracing the sources and sinks of hydrocarbons can...Hydrocarbons are one of the important fluids within the Earth's crust,and different biotic and abitoic processes can generate hydrocarbon during geological periods.Tracing the sources and sinks of hydrocarbons can help us better understand the carbon cycle of the earth.In this study,an improved approach of adsorbed hydrocarbons extraction from sediments was established.The improved thermal desorption approach,compound-specific isotope analysis and position-specific isotope analysis were integrated to investigate the molecular and intramolecular isotope fractionation between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The isotopic compositions of the terminal position carbon of propane(δ^(13)C_(terminal))serves as a correlation indicator between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The tight sandstone gas from the Turpan-Hami Basin is a first case study for the application of this novel method to trace hydrocarbon origins.The results showed that the hydrocarbons in the tight sandstone gases in the study area most likely originated from humic organic matter(typeⅢkerogen)at an early mature stage.δ^(13)C_(terminal)values of the thermally desorbed propane gases from different source rocks were distinguishable and the values of the tight sandstone gases significantly overlap with those of the Lower Jurassic Sangonghe source rocks,suggesting their genetic relationship.Overall,the results provided novel position-specific carbon isotopic constraints on origins of hydrocarbons.展开更多
Methane(CH4),the predominant component of natural gas and shale gas,is regarded as a promising carbon feedstock for chemical synthesis[1].However,considering the extreme stability of CH4 molecules,it's quite chall...Methane(CH4),the predominant component of natural gas and shale gas,is regarded as a promising carbon feedstock for chemical synthesis[1].However,considering the extreme stability of CH4 molecules,it's quite challenging in simultaneously achieving high activity and selectivity for target products under mild conditions,especially when synthesizing high-value C2t chemicals such as ethanol[2].The conversion of methane to ethanol by photocatalysis is promising for achieving transformation under ambient temperature and pressure conditions.Currently,the apparent quantum efficiency(AQE)of solar-driven methane-to-ethanol conversion is generally below 0.5%[3,4].Furthermore,the stability of photocatalysts remains inadequate,offering substantial potential for further improvement.展开更多
G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains...G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains a persistent challenge.Here,we report that a PW17/hemin(PW17:5’-GGGTAGGGCGGGTTGGG-3’),adopting the 5’-5’stacked dimeric parallel G4 topology,can realize the enantioselective induction in intramolecular cyclopropanation of allyl diazoacetates with enantioselectivity up to 87%ee.Spectroscopic characterization and catalytic results demonstrate that the relatively open G-quartet of the 3’terminal in dimeric PW17 contributes a catalytic pocket for hemin accommodation and plays a pivotal role in enantioselective control.This finding expands the unique repertoire of heme enzyme using biological scaffolds from proteins to nucleic acids and resolves the long-standing challenge of stereochemical control in G4/hemin catalysis.展开更多
The low-voltage plateau capacity,which is highly related to the internal closed pores in hard carbon(HC),is the main contributor to the total capacity in sodium-ion batteries.However,the formation mechanism of closed ...The low-voltage plateau capacity,which is highly related to the internal closed pores in hard carbon(HC),is the main contributor to the total capacity in sodium-ion batteries.However,the formation mechanism of closed pores and modification strategies at the molecular level in HC polymer precursors remain poorly understood.Furthermore,the practical applications of HCs are significantly impeded by their low initial coulombic efficiency(ICE).In this study,the intramolecular heteroatom doping(IHP)effect was proposed to facilitate the formation of closed pores in polymer-derived HC for the first time by grafting sulfonyl,ether,and carbonyl groups between benzene rings.As a result,the optimized HC sample showed an increased closed pore volume and low Na^(+)adsorption energy,which delivered a reversible capacity of 307.9 mAh·g^(-1)and superior rate capability.Through further optimized presodiation,the formed presodiated HC featuring a thin,smooth,and dense solid electrolyte interface film exhibited a remarkably enhanced ICE of 94.4%and enhanced cycling stability(93.6%over 3000 cycles).This study provides an in-depth understanding of the formation mechanisms of closed pores via IHP engineering and develops a new synergistic strategy involving presodiation to prepare highly stable HC anodes.展开更多
The excited state intramolecular proton transfer （ESIPT） coupled charge transfer of baicalein has been investigated using steady-state spectroscopic experiment and quantum chemistry calculations. The absence of the ...The excited state intramolecular proton transfer （ESIPT） coupled charge transfer of baicalein has been investigated using steady-state spectroscopic experiment and quantum chemistry calculations. The absence of the absorption peak from S1 excited state both in the experi-mental and calculated absorption spectra indicates that S1 is a dark state. The dark excited state S1 results in the very weak fluorescence of solid baicalein in the experiment. The fron- tier molecular orbital and the charge difference densities of baicalein show clearly that the S1 state is a charge-transfer state whereas the S2 state is a locally excited state. The only one stationary point on the potential energy profile of excited state suggests that the ESIPT reaction of baicalein is a barrierless process.展开更多
Photo-induced intramolecular electron transfer （PIET） and intramolecular vibrational relaxation （IVR） dynamics of the excited state of rhodamine 6G （Rh6G＋） in DMSO are investigated by multiplex transient gratin...Photo-induced intramolecular electron transfer （PIET） and intramolecular vibrational relaxation （IVR） dynamics of the excited state of rhodamine 6G （Rh6G＋） in DMSO are investigated by multiplex transient grating. Two major compo- nents are resolved in the dynamics of Rh6G＋. The first component, with a lifetime τTPIET = 140 fs-260 fs, is attributed to PIET from the phenyl ring to the xanthene plane. The IVR process occurring in the range ZIVR = 3.3 ps-5.2 ps is much slower than the first component. The PIET and IVR processes occurring in the excited state of Rh6G＋ are quantitatively determined, and a better understanding of the relationship between these processes is obtained.展开更多
The binding energy spectrum and electron momentum distributions for the outer valence orbitals of n-propyl iodide molecule have been measured using the electron momentum spectrometer employing non-coplanar asymmetric ...The binding energy spectrum and electron momentum distributions for the outer valence orbitals of n-propyl iodide molecule have been measured using the electron momentum spectrometer employing non-coplanar asymmetric geometry at impact energy of 2.5 keV plus binding energy. The ionization bands have been assigned in detail via the high accuracy SACCI general-R method calculation and the experimental momentum profiles are compared with the theoretical ones calculated by Hartree-Fock and B3LYP/aug-cc-pVTZ（C,H）6-311G？？（I）. The spin-orbit coupling effect and intramolecular orbital interaction have been analyzed for the outermost two bands, which are assigned to the iodine 5p lone pairs, using NBO method and non-relativistic as well as relativistic calculations. It is found that both of the interactions will lead to the observed differences in electron momentum distributions. The experimental results agree with the relativistic theoretical momentum profiles, indicating that the spin-orbit coupling effect dominates in n-propyl iodide molecule.展开更多
An alternative construction of A-B-D ring-system of erythrinan and homoerythrinan alkaloids by TiCl4-mediated tandem semipinacol/intramolecular Schmidt reaction of α-siloxyepoxyazide was addressed and the unusual epo...An alternative construction of A-B-D ring-system of erythrinan and homoerythrinan alkaloids by TiCl4-mediated tandem semipinacol/intramolecular Schmidt reaction of α-siloxyepoxyazide was addressed and the unusual epoxidation stereoselectivity was observed in preparation of the substrate once again.展开更多
Asymmetric intramolecular cyclopropanation of allylic diazoacetate was investigated using a chiral (β-diketone)-copper complex as catalyst, excellent yield and enantioselectivity were achieved. Some factors influenci...Asymmetric intramolecular cyclopropanation of allylic diazoacetate was investigated using a chiral (β-diketone)-copper complex as catalyst, excellent yield and enantioselectivity were achieved. Some factors influencing enantioselectivity were discussed.展开更多
The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy l...The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy levels of Eu 3+ , Tb 3+ , Sm 3+ , Dy 3+ were studied. The intramolecular energy transfer processes from the two aromatic carboxylic acid ligands to rare earth ions were also discussed on the basis of the measurement results of luminescence intensities, lifetimes and quantum efficiencies.展开更多
To develop smart and efficient near-infrared(NIR)organic dyes for photothermal cancer therapy is of great challenge.Herein,a pH-sensitive NIR dye BTN with donor–acceptor–donor scaffold has been synthesized.Two perip...To develop smart and efficient near-infrared(NIR)organic dyes for photothermal cancer therapy is of great challenge.Herein,a pH-sensitive NIR dye BTN with donor–acceptor–donor scaffold has been synthesized.Two periphery electron-donating dimethylamine groups in BTN can not only promote the intramolecular photoinduced electron transfer(PET),but also bind protons to transform into electron-deficient ammonium cation for enhanced intramolecular charge transfer(ICT)under acidic circumstance.Through enveloping with amphiphilic polymeric 1,2-distearoyl-ras-glycerol-3-phosphatidyl ethanolamine-N-polyethyleneglycol-2000(DSPE-mPEG2000),BTN nanoparticles(NPs)were fabricated with robust NIR absorption covering 600–900 nm,excellent photothermal conversion efficiency(43.2%),and good photostability.Additionally,BTN NPs can selectively target lysosomes.Through tailing intravenous injection into tumor-bearing nude mice,BTN NPs demonstrate outstanding photoacoustic/photothermal/fluorescence imaging-guided photothermal therapy for tumor ablation.展开更多
In this paper, we estimate the rate of contact formation between two residues in the interior of the proteins using the Szabo, Schulten, and Schulten formula with the probability distribution P（r） based on 375 prote...In this paper, we estimate the rate of contact formation between two residues in the interior of the proteins using the Szabo, Schulten, and Schulten formula with the probability distribution P（r） based on 375 proteins from PDB （Protein Data Bank）. The probability distribution for residue pair in proteins is different from the Gaussian distribution, especially for short distance between two residues in proteins. The rate of contact formation in the interior of protein is discussed as a function of distance n （=｜j -i｜） between two residues, and it decreases monotonically with n and follows the scaling relationship of k ∝ n^-γ with γ= 1.43 for the contact radius a = 0.40 nm and γ=1.05 for a = 0.50 nm. The diffusion coefficient for the relative diffusion of two residues in the interior of proteins is estimated as D = 6.4 × 10^-6 cm^2/s, which is close to the result that is found for monomer diffusion.展开更多
Phase-transfer-catalyzed intramolecular cyclization reaction of forming benzo[b]furan and 3-methyleneisoin- doline-1-one derivatives has been developed. The cyclization reaction of propargylic carbonates was also de- ...Phase-transfer-catalyzed intramolecular cyclization reaction of forming benzo[b]furan and 3-methyleneisoin- doline-1-one derivatives has been developed. The cyclization reaction of propargylic carbonates was also de- scribed under metal-free condition and the reaction was reported by Pd and Ni before. The reaction condi- tions and the scope of the process are examined. The catalysts are cheap and environmentally friendly and the substrates are readily available and the procedure is simple, rapid, and general. The development of C-O and C-N bond formation processes via an overall structural isomerization represents the most atom-eco- nomical approach.展开更多
Objective:The inter-α-trypsin inhibitor heavy chain 4(ITIH4)protein is involved in the development of tumors.However,the relationship between ITIH4 and ovarian cancer(OC)has not been extensively examined.This study a...Objective:The inter-α-trypsin inhibitor heavy chain 4(ITIH4)protein is involved in the development of tumors.However,the relationship between ITIH4 and ovarian cancer(OC)has not been extensively examined.This study aimed to explore the effect of ITIH4 on OC and to identify its underlying mechanism.Methods:Expressions of ITIH4 in OC tissues and cells were determined using quantitative reverse transcription polymerase chain reaction(RT-qPCR)and western blots.The function of ITIH4 in the OC cell line HO8910 pm was tested via ITIH4 knockdown.The cell growth rate was measured using MTT and colony formation assays.Flow cytometry was performed to evaluate cell cycle progression.Cell migration and invasion abilities were observed using the transwell migration assay.Results:ITIH4 was downregulated in OC tissues and cells.ITIH4 knockdown promoted cell growth and cell cycle progression.Consistent with these results,inhibition of ITIH4 in OC cells significantly increased cell migration and invasion abilities.Cox regression analysis suggests that ITIH4 expression alone is not a good predictor of the prognosis of malignant ovarian tumors in patients.Conclusions:ITIH4 inhibits the progression of OC,suggesting that ITIH4 may be a useful biomarker for OC.This study may provide a potential novel target for the treatment of OC.展开更多
基金financial support from the National Nature Science Foundation of China(Nos.81760625,81660576 and81560563)Projects of Guizhou Province(Nos.[2016]5623,JG[2016]06,[2019]1402,[2017]5609 and[2018]5781)。
文摘A quinine-derived thiourea-catalyzed inter-/intramolecular Michael cycloaddition of chromoneoxindole/benzofuranone synthons with 3-substituted methylenebenzofuranones has been established,which constructed enantiomerically pure bispiro[benzofuran-oxindole/benzofuran-chromanone]s bearing five consecutive stereocenters including two spiro quaternary carton centers in good yields(up to 93%) with high diastereoselectivities(up to>20:1 dr) and good enantioselectivities(up to>99% ee).Moreover,this is the first example of bifunctional chromone-benzofuranone synthon directed organocatalytic tandem reaction,and also the first example of the bispiro[benzofuran-oxindole] and bispirobenzofuranone,potentially useful in medicinal chemistry.
文摘Inter-and intramolecular quenching of zinc phthalocyanine fluorescence by anthraquinone has been studied.The diminutions of fluorescence quantum yield and life-time are due primarily to electron transfer.Apparent electron transfer rate constants were calculated depending on the chain length and solvent polarity.
基金financially supported by the National Natural Science Foundation of China(Grant No.42102202)U.S.Department of Energy Geosciences program(DE-SC0016271)。
文摘Hydrocarbons are one of the important fluids within the Earth's crust,and different biotic and abitoic processes can generate hydrocarbon during geological periods.Tracing the sources and sinks of hydrocarbons can help us better understand the carbon cycle of the earth.In this study,an improved approach of adsorbed hydrocarbons extraction from sediments was established.The improved thermal desorption approach,compound-specific isotope analysis and position-specific isotope analysis were integrated to investigate the molecular and intramolecular isotope fractionation between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The isotopic compositions of the terminal position carbon of propane(δ^(13)C_(terminal))serves as a correlation indicator between trace hydrocarbon gases within sediments and geological hydrocarbon deposits.The tight sandstone gas from the Turpan-Hami Basin is a first case study for the application of this novel method to trace hydrocarbon origins.The results showed that the hydrocarbons in the tight sandstone gases in the study area most likely originated from humic organic matter(typeⅢkerogen)at an early mature stage.δ^(13)C_(terminal)values of the thermally desorbed propane gases from different source rocks were distinguishable and the values of the tight sandstone gases significantly overlap with those of the Lower Jurassic Sangonghe source rocks,suggesting their genetic relationship.Overall,the results provided novel position-specific carbon isotopic constraints on origins of hydrocarbons.
基金the support from the National Natural Science Foundation of China(52202306)Program from Guangdong Introducing Innovative and Entrepreneurial Teams(2019ZT08L101 and RCTDPT-2020-001)+1 种基金Shenzhen Key Laboratory of Eco-materials and Renewable Energy(ZDSYS20200922160400001)the Provincial Talent Plan of Guangdong(2023TB0012).
文摘Methane(CH4),the predominant component of natural gas and shale gas,is regarded as a promising carbon feedstock for chemical synthesis[1].However,considering the extreme stability of CH4 molecules,it's quite challenging in simultaneously achieving high activity and selectivity for target products under mild conditions,especially when synthesizing high-value C2t chemicals such as ethanol[2].The conversion of methane to ethanol by photocatalysis is promising for achieving transformation under ambient temperature and pressure conditions.Currently,the apparent quantum efficiency(AQE)of solar-driven methane-to-ethanol conversion is generally below 0.5%[3,4].Furthermore,the stability of photocatalysts remains inadequate,offering substantial potential for further improvement.
文摘G-quadruplex DNA(G4)can function as a kind of nucleic acid apoenzyme for constructing G4/hemin biocatalyst to mimic the catalytic function of hemoprotein.However,achieving stereoselective control with G4/hemin remains a persistent challenge.Here,we report that a PW17/hemin(PW17:5’-GGGTAGGGCGGGTTGGG-3’),adopting the 5’-5’stacked dimeric parallel G4 topology,can realize the enantioselective induction in intramolecular cyclopropanation of allyl diazoacetates with enantioselectivity up to 87%ee.Spectroscopic characterization and catalytic results demonstrate that the relatively open G-quartet of the 3’terminal in dimeric PW17 contributes a catalytic pocket for hemin accommodation and plays a pivotal role in enantioselective control.This finding expands the unique repertoire of heme enzyme using biological scaffolds from proteins to nucleic acids and resolves the long-standing challenge of stereochemical control in G4/hemin catalysis.
基金financially supported by the Ministry of Industry and Information Technology of Chinathe National Natural Science Foundation of China(No.52403263)+1 种基金Technology Research Project of Jiangxi Provincial Department of Education(No.GJJ2200385)Jiangxi Provincial Natural Science Foundation(Nos.20244BCE52213,20242BAB23031 and 20232BAB204006)。
文摘The low-voltage plateau capacity,which is highly related to the internal closed pores in hard carbon(HC),is the main contributor to the total capacity in sodium-ion batteries.However,the formation mechanism of closed pores and modification strategies at the molecular level in HC polymer precursors remain poorly understood.Furthermore,the practical applications of HCs are significantly impeded by their low initial coulombic efficiency(ICE).In this study,the intramolecular heteroatom doping(IHP)effect was proposed to facilitate the formation of closed pores in polymer-derived HC for the first time by grafting sulfonyl,ether,and carbonyl groups between benzene rings.As a result,the optimized HC sample showed an increased closed pore volume and low Na^(+)adsorption energy,which delivered a reversible capacity of 307.9 mAh·g^(-1)and superior rate capability.Through further optimized presodiation,the formed presodiated HC featuring a thin,smooth,and dense solid electrolyte interface film exhibited a remarkably enhanced ICE of 94.4%and enhanced cycling stability(93.6%over 3000 cycles).This study provides an in-depth understanding of the formation mechanisms of closed pores via IHP engineering and develops a new synergistic strategy involving presodiation to prepare highly stable HC anodes.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.61137005 and No.10974023）, the Program for Liaoning Excellent Talents in University （No.LJQ2012002）, and the Program for New Century Excellent Talents in University （No.NCET-12-0077）.
文摘The excited state intramolecular proton transfer （ESIPT） coupled charge transfer of baicalein has been investigated using steady-state spectroscopic experiment and quantum chemistry calculations. The absence of the absorption peak from S1 excited state both in the experi-mental and calculated absorption spectra indicates that S1 is a dark state. The dark excited state S1 results in the very weak fluorescence of solid baicalein in the experiment. The fron- tier molecular orbital and the charge difference densities of baicalein show clearly that the S1 state is a charge-transfer state whereas the S2 state is a locally excited state. The only one stationary point on the potential energy profile of excited state suggests that the ESIPT reaction of baicalein is a barrierless process.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21003033 and 21203047)the Guangxi Provincial Natural Science Foundation,China(Grant Nos.2012GXNSFBA053012 and 2014GXNSFAA118019)the Research Foundation of Education Bureau of Guangxi Zhuang Autonomous Region,China(Grant No.ZD2014127)
文摘Photo-induced intramolecular electron transfer （PIET） and intramolecular vibrational relaxation （IVR） dynamics of the excited state of rhodamine 6G （Rh6G＋） in DMSO are investigated by multiplex transient grating. Two major compo- nents are resolved in the dynamics of Rh6G＋. The first component, with a lifetime τTPIET = 140 fs-260 fs, is attributed to PIET from the phenyl ring to the xanthene plane. The IVR process occurring in the range ZIVR = 3.3 ps-5.2 ps is much slower than the first component. The PIET and IVR processes occurring in the excited state of Rh6G＋ are quantitatively determined, and a better understanding of the relationship between these processes is obtained.
文摘The binding energy spectrum and electron momentum distributions for the outer valence orbitals of n-propyl iodide molecule have been measured using the electron momentum spectrometer employing non-coplanar asymmetric geometry at impact energy of 2.5 keV plus binding energy. The ionization bands have been assigned in detail via the high accuracy SACCI general-R method calculation and the experimental momentum profiles are compared with the theoretical ones calculated by Hartree-Fock and B3LYP/aug-cc-pVTZ（C,H）6-311G？？（I）. The spin-orbit coupling effect and intramolecular orbital interaction have been analyzed for the outermost two bands, which are assigned to the iodine 5p lone pairs, using NBO method and non-relativistic as well as relativistic calculations. It is found that both of the interactions will lead to the observed differences in electron momentum distributions. The experimental results agree with the relativistic theoretical momentum profiles, indicating that the spin-orbit coupling effect dominates in n-propyl iodide molecule.
文摘An alternative construction of A-B-D ring-system of erythrinan and homoerythrinan alkaloids by TiCl4-mediated tandem semipinacol/intramolecular Schmidt reaction of α-siloxyepoxyazide was addressed and the unusual epoxidation stereoselectivity was observed in preparation of the substrate once again.
文摘Asymmetric intramolecular cyclopropanation of allylic diazoacetate was investigated using a chiral (β-diketone)-copper complex as catalyst, excellent yield and enantioselectivity were achieved. Some factors influencing enantioselectivity were discussed.
文摘The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy levels of Eu 3+ , Tb 3+ , Sm 3+ , Dy 3+ were studied. The intramolecular energy transfer processes from the two aromatic carboxylic acid ligands to rare earth ions were also discussed on the basis of the measurement results of luminescence intensities, lifetimes and quantum efficiencies.
基金The work was financially supported by the Natural Science Foundation of Jiangsu Province(Nos.BK20200092 and BK20200710).
文摘To develop smart and efficient near-infrared(NIR)organic dyes for photothermal cancer therapy is of great challenge.Herein,a pH-sensitive NIR dye BTN with donor–acceptor–donor scaffold has been synthesized.Two periphery electron-donating dimethylamine groups in BTN can not only promote the intramolecular photoinduced electron transfer(PET),but also bind protons to transform into electron-deficient ammonium cation for enhanced intramolecular charge transfer(ICT)under acidic circumstance.Through enveloping with amphiphilic polymeric 1,2-distearoyl-ras-glycerol-3-phosphatidyl ethanolamine-N-polyethyleneglycol-2000(DSPE-mPEG2000),BTN nanoparticles(NPs)were fabricated with robust NIR absorption covering 600–900 nm,excellent photothermal conversion efficiency(43.2%),and good photostability.Additionally,BTN NPs can selectively target lysosomes.Through tailing intravenous injection into tumor-bearing nude mice,BTN NPs demonstrate outstanding photoacoustic/photothermal/fluorescence imaging-guided photothermal therapy for tumor ablation.
基金This research was financially supported by the National Natural Science Foundation of China (No. 20574052)Program for New Century Excellent Talents in University,and Natural Science Foundation of Zhejiang Province (No. R404047)
文摘In this paper, we estimate the rate of contact formation between two residues in the interior of the proteins using the Szabo, Schulten, and Schulten formula with the probability distribution P（r） based on 375 proteins from PDB （Protein Data Bank）. The probability distribution for residue pair in proteins is different from the Gaussian distribution, especially for short distance between two residues in proteins. The rate of contact formation in the interior of protein is discussed as a function of distance n （=｜j -i｜） between two residues, and it decreases monotonically with n and follows the scaling relationship of k ∝ n^-γ with γ= 1.43 for the contact radius a = 0.40 nm and γ=1.05 for a = 0.50 nm. The diffusion coefficient for the relative diffusion of two residues in the interior of proteins is estimated as D = 6.4 × 10^-6 cm^2/s, which is close to the result that is found for monomer diffusion.
文摘Phase-transfer-catalyzed intramolecular cyclization reaction of forming benzo[b]furan and 3-methyleneisoin- doline-1-one derivatives has been developed. The cyclization reaction of propargylic carbonates was also de- scribed under metal-free condition and the reaction was reported by Pd and Ni before. The reaction condi- tions and the scope of the process are examined. The catalysts are cheap and environmentally friendly and the substrates are readily available and the procedure is simple, rapid, and general. The development of C-O and C-N bond formation processes via an overall structural isomerization represents the most atom-eco- nomical approach.
基金supported by Guangxi Scientific Research and Technology Development Project (No. 14124004-1-24)
文摘Objective:The inter-α-trypsin inhibitor heavy chain 4(ITIH4)protein is involved in the development of tumors.However,the relationship between ITIH4 and ovarian cancer(OC)has not been extensively examined.This study aimed to explore the effect of ITIH4 on OC and to identify its underlying mechanism.Methods:Expressions of ITIH4 in OC tissues and cells were determined using quantitative reverse transcription polymerase chain reaction(RT-qPCR)and western blots.The function of ITIH4 in the OC cell line HO8910 pm was tested via ITIH4 knockdown.The cell growth rate was measured using MTT and colony formation assays.Flow cytometry was performed to evaluate cell cycle progression.Cell migration and invasion abilities were observed using the transwell migration assay.Results:ITIH4 was downregulated in OC tissues and cells.ITIH4 knockdown promoted cell growth and cell cycle progression.Consistent with these results,inhibition of ITIH4 in OC cells significantly increased cell migration and invasion abilities.Cox regression analysis suggests that ITIH4 expression alone is not a good predictor of the prognosis of malignant ovarian tumors in patients.Conclusions:ITIH4 inhibits the progression of OC,suggesting that ITIH4 may be a useful biomarker for OC.This study may provide a potential novel target for the treatment of OC.
