12 perfluorinated compounds（PFCs） in human blood from workers in a textile mill in Shandong province and several barbershops in Tianjin were analyzed in this study. It was found that perfluorooctanesulfonate（PFOS）...12 perfluorinated compounds（PFCs） in human blood from workers in a textile mill in Shandong province and several barbershops in Tianjin were analyzed in this study. It was found that perfluorooctanesulfonate（PFOS） and perfluorooctanoate（PFOA） were the most prominent PFCs, with average concentrations of 5.73 mg/L and 5.46 mg/L for textile workers, and 2.55 mg/L and 2.84 mg/L for barbers.PFOS and perfluorohexanesulfonate（PFHxS） concentrations revealed a positive correlation in blood samples（p 〈 0.01）, and concentrations among PFOS, perfluorononanoic acid（PFNA） and perfluorodecanoic acid（PFDA） also revealed positive correlations（p 〈 0.01）. The influence of gender and age on PFC concentration in blood was also investigated, and the results showed that there was no statistically significant difference between the male and female samples, as well as in samples from people with different ages. Generally speaking, the textile workers展开更多
AIM： To explore effects of huoxiangzhengqi liquid （HXZQ） on enteric mucosal immune responses in mice with Bacillus dysenteriae and Salmonella typhimurium induced diarrhea （BSD）. METHODS： BSD was induced in Balb/...AIM： To explore effects of huoxiangzhengqi liquid （HXZQ） on enteric mucosal immune responses in mice with Bacillus dysenteriae and Salmonella typhimurium induced diarrhea （BSD）. METHODS： BSD was induced in Balb/c mice by oral administration with Bacillus dysenteriae and Salmonella typhimurium. HXZQ was administrated from the day of diarrhea induction at dosages of 5.21 g/kg and 0.52 g/kg, respectively. The onset of diarrhea and lasting time were recorded. Peyer＇s patches and peripheral lymphocytes were prepared for flow cytometry, and levels of TNF-α in peripheral blood and enteric tissue homogenates were determined with ELISA. Student＇s t test was employed for statistics. RESULTS： Mice in BSD group started showing continuous diarrhea on the day of induction until the fourth day when they were sacrificed. Diarrhea in the mice of HXZQ high and low dose groups lasted for 36 and 54 h, respectively. There were more CD4^＋ and CD8^＋ cells in peripheral blood, fewer CD4^＋ cells in Peyer＇s patches in BSD mice compared to normal mice. Fewer CD4^＋ and CD8^＋ cells was shown in the mice in HXZQ high group compared to BSD mice. In Peyer＇s patch, there were more CD8^＋ cells in mice in HXZQ high and low dose groups and more CD4^＋ in mice in HXZQ high group. Higher levels of TNF-α in peripheral blood and intestinal tissue homogenates in BSD group were observed. Mice in HXZQ high group showed decreased levels of TNF-α in peripheral blood and enteric tissue homogenates. CONCLUSION： The immune regulation of CD4^＋ and CD8^＋ cells in Peyer＇s patch and suppression of TNF-α levels in enteric homogenates may partially explain the effect of HXZQ on improvement of BSD.展开更多
Hepatocellular carcinoma(HCC)is one of the most common malignancies and a leading cause of cancer-related death worldwide.Surgery remains the primary and most successful therapy option for the treatment of early-and m...Hepatocellular carcinoma(HCC)is one of the most common malignancies and a leading cause of cancer-related death worldwide.Surgery remains the primary and most successful therapy option for the treatment of early-and mid-stage HCCs,but the high heterogeneity of HCC renders prognostic prediction challenging.The construction of relevant prognostic models helps to stratify the prognosis of surgically treated patients and guide personalized clinical decision-making,thereby improving patient survival rates.Currently,the prognostic assessment of HCC is based on several commonly used staging systems,such as Tumor-Node-Metastasis(TNM),Cancer of the Liver Italian Program(CLIP),and Barcelona Clinic Liver Cancer(BCLC).Given the insufficiency of these staging systems and the aim to improve the accuracy of prognostic prediction,researchers have incorporated further prognostic factors,such as microvascular infiltration,and proposed some new prognostic models for HCC.To provide insights into the prospects of clinical oncology research,this review describes the commonly used HCC staging systems and new models proposed in recent years.展开更多
Cluster science as a bridge linking atomic molecular physics and condensed matter inspired the nanomaterials development in the past decades, ranging from the single-atom catalysis to ligand-protected noble metal clus...Cluster science as a bridge linking atomic molecular physics and condensed matter inspired the nanomaterials development in the past decades, ranging from the single-atom catalysis to ligand-protected noble metal clusters. The corresponding studies not only have been restricted to the search for the geometrical structures of clusters, but also have promoted the development of cluster-assembled materials as the building blocks. The CALYPSO cluster prediction method combined with other computational techniques have significantly stimulated the development of the cluster-based nanomaterials. In this review, we will summarize some good cases of cluster structure by CALYPSO method, which have also been successfully identified by the photoelectron spectra experiments. Beginning with the alkali-metal clusters, which serve as benchmarks, a series of studies are performed on the size-dependent elemental clusters which possess relatively high stability and interesting chemical physical properties. Special attentions are paid to the boron-based clusters because of their promising applications. The NbSi12 and BeB16 clusters, for example, are two classic representatives of the silicon-and boron-based clusters, which can be viewed as building blocks of nanotubes and borophene. This review offers a detailed description of the structural evolutions and electronic properties of medium-sized pure and doped clusters, which will advance fundamental knowledge of cluster-based nanomaterials and provide valuable information for further theoretical and experimental studies.展开更多
Interfacial heat transfer behavior between the molten steel and twin-rolls is a key issue in the strip casting process,and it has already attracted wide attention from industrial and academic communities of steel.The ...Interfacial heat transfer behavior between the molten steel and twin-rolls is a key issue in the strip casting process,and it has already attracted wide attention from industrial and academic communities of steel.The research methods and influencing factors on the interfacial heat transfer were summarized.Numerical simulation models,semi-industrial scale,and laboratory equipment have been developed in this field,and these methods were also improved by worldwide researchers based on the development of computer,automatic,and visual technologies.Coating properties,naturally deposited film,and casting parameters are the main factors which affect the heat transfer significantly.Although lots of research has been carried out,the internal relations among these influencing factors,interfacial heat transfer,and the quality of the strip are still worth to be further explored.Keywords Strip casting Interfacial heat transfer Simulation method Coating property Naturally deposited film Casting parameter.展开更多
Typical Q235 low-carbon steel samples with different hydrogen contents(0.0004,0.0008,and 0.0013 wt.%)were prepared by adjusting the environment humidity and moisture.The effects of hydrogen on interfacial heat transfe...Typical Q235 low-carbon steel samples with different hydrogen contents(0.0004,0.0008,and 0.0013 wt.%)were prepared by adjusting the environment humidity and moisture.The effects of hydrogen on interfacial heat transfer,contact behavior,and microstructure evolution were investigated using a novel droplet solidification technique.The results revealed that when the hydrogen content increases from 0.0004 to 0.0013 wt.%,the maximum heat flux between the molten steel and cooling substrate decreases from 8.01 to 6.19 MW/m^(2),and the total heat removed in the initial 2 s reduces from 10.30 to 8.27 MJ/m^(2).Moreover,the final contact angle between the molten steel and substrate increases from 103.741°to 113.697°,and the number of pores on the droplet bottom surface increases significantly from 21 to 210 with the increase in hydrogen.The surface roughness of the droplet bottom surface increases from 20.902 to 49.181 pm.In addition,the average grain size of the droplet increases from 14.778 to 33.548 pm with the increase in the hydrogen content.The interfacial contact condition becomes worse due to the escape of hydrogen from the steel matrix during the cooling process,which leads to the reduction in the interfacial heat transfer and the increase in the grain size.展开更多
When groundwater pollution occurs,to come up with an efficient remediation plan,it is particularly important to collect information of contaminant source(location and source strength)and hydraulic conductivity field o...When groundwater pollution occurs,to come up with an efficient remediation plan,it is particularly important to collect information of contaminant source(location and source strength)and hydraulic conductivity field of the site accurately and quickly.However,the information can not be obtained by direct observation,and can only be derived from limited measurement data.Data assimilation of observations such as head and concentration is often used to estimate parameters of contaminant source.As for hydraulic conductivity field,especially for complex non-Gaussian field,it can be directly estimated by geostatistics method based on limited hard data,while the accuracy is often not high.Better estimation of hydraulic conductivity can be achieved by solving inverse groundwater problem.Therefore,in this study,the multi-point geostatistics method Quick Sampling(QS)is proposed and introduced for the first time and combined with the iterative local updating ensemble smoother(ILUES)to develop a new data assimilation framework QS-ILUES.It helps to solve the contaminant source parameters and non-Gaussian hydraulic conductivity field simultaneously by assimilating hydraulic head and pollutant concentration data.While the pilot points are utilized to reduce the dimension of hydraulic conductivity field,the influence of pilot points’layout and the ensemble size of ILUES algorithm on the inverse simulation results are further explored.展开更多
In this study,the substructure formation in a multi-pass rolled aluminium single crystal{001}<110>was investigated by the crystal plasticity finite element model,and the predations were validated by experimental...In this study,the substructure formation in a multi-pass rolled aluminium single crystal{001}<110>was investigated by the crystal plasticity finite element model,and the predations were validated by experimental observations at both macro-and micro-scale.A finite element model for multi-pass rolling was developed to follow the real experimental rolling scheme,by which the through-thickness macroscopic subdivision was successfully predicted up to a 90%reduction.The macro-subdivision was featured by forming matrix bands through the thickness,and the deformation behaviours,in terms of slip activity,shear strain and crystal rotation,alternated between matrix bands.The development of matrix bands,stability of crystal orientations,and correlation between slip activity,shear strain and crystal rotation have been investigated.Another modelling method,Submodel,was used to exceedingly increase the mesh resolution in smaller regions of interest,and the experimentally observed microstructure,i.e.,micro-subdivision was explicitly and spatially revealed.Similar predictions were obtained in Submodels with different element sizes,which proves the feasibility of this method in predicting microstructure formation.It was found that the substructure formation by varying slip activity and crystal rotation between domains is energy favourable.The procedure of substructure formation was explained based on the predictions,three types of substructure have been identified,and the substructure formation was discussed.展开更多
The development of practical methods for the direct and selective C(sp^(3))‒H functionalization of hydrocarbons is an attractive topic in synthetic chemistry.Although the radical‐mediated hydrogen atom transfer(HAT)p...The development of practical methods for the direct and selective C(sp^(3))‒H functionalization of hydrocarbons is an attractive topic in synthetic chemistry.Although the radical‐mediated hydrogen atom transfer(HAT)process has shown considerable potential in such reactions,it still faces fundamental problems associated with reactivity and selectivity.Herein,we report a convenient and economic approach to site‐selective C(sp^(3))‒H sulfonylation via photo‐induced HAT catalysis.Employing a conjugated polycyclic quinone as a direct HAT photocatalyst,commercially available inorganic sulfinates as the sulfonylation source,copper triflate as an inexpensive oxidant,a variety of toluene derivatives and cycloalkanes were converted into biologically and synthetically interesting sulfone products under mild conditions.The mechanistic studies reveal that the reaction sequence involves direct HAT‐induced radical formation and a subsequent copper‐mediated organometallic process for the C‒S bond formation.This method offers an appealing opportunity to furnish high value‐added products from abundant hydrocarbon starting materials and inexpensive reagents.展开更多
Reconstruction during the catalytic process has been considered to play a key role for the performance.Here we report a RuNiPO based catalyst for efficient alkaline hydrogen evolution reaction(HER),which can benefit f...Reconstruction during the catalytic process has been considered to play a key role for the performance.Here we report a RuNiPO based catalyst for efficient alkaline hydrogen evolution reaction(HER),which can benefit from a long-term reconstruction during HER for 10 h to continuously increase the performance.The final catalyst(e-RuNiPO)shows a huge morphology change from bulk sphere to highly exposed layered structure in the electrocatalysis process,and exhibits an interesting electronic structure modification with the electron transfer from Ru to Ni for better interfacial interaction and quick charge transfer.Due to the favorable morphology with more exposed active sites and the optimized electronic structure,the final catalyst can achieve an outstanding performance with only an overpotential of 15 mV at 10 mA cm^(-2)(with a good stability more than 100 h),even outperforming the performance of benchmark 20 wt%Pt/C catalyst(18 mV at 10 mA cm^(-2))by using a much lower Ru content.展开更多
Hydrophilic rare-earth up-conversion nanophosphors(UCNPs)with small sizes and a strong up-conversion luminescence have attracted much interest.Herein the simultaneous control of morphologies and the up-conversion lumi...Hydrophilic rare-earth up-conversion nanophosphors(UCNPs)with small sizes and a strong up-conversion luminescence have attracted much interest.Herein the simultaneous control of morphologies and the up-conversion luminescence intensities was reported for NaYF_(4)∶Yb/Er nanophosphors by a facile hydrothermal procedure with different surfactants.With the change of the surfactants from polyvinylpyrrolidone(PVP)to sodium citrate(CIT),edetate disodium(EDTA)or sodium dodecyl benzenesulfonate(SDBS),the morphology of NaYF_(4)∶Yb/Er nanophosphors transformed from nanoparticles with a diameter of about 70.0 nm to hexagonal nanoblocks with a thickness of about 125.0 nm and a length of about 240.0 nm,nanorods with a diameter of about 700.0 nm and a length of about 2.6μm,or nanowires with a diameter of 250.0 nm and a length of about 3.2μm.Simultaneously,their up-conversion luminescence intensity went down gradually under laser irradiation at a wavelength of 980 nm due to the increase of photobleaching.PVP-capped NaYF_(4)∶Yb/Er nanoparticles exhibited the smallest size and the strongest up-conversion luminescence intensity.Biological experiment results revealed that NaYF_(4)∶Yb/Er nanophosphors exhibited a high biocompatibility and could be used as biological labels with a perfect signal-to-noise ratio for cancer cell imaging.展开更多
Spinal cord injury（SCI） is a severe trauma to the central nervous system（CNS）. This article reviews recent advances in cellular transplantation to treat SCI. Transplanted cells can supply new neurons to replace in...Spinal cord injury（SCI） is a severe trauma to the central nervous system（CNS）. This article reviews recent advances in cellular transplantation to treat SCI. Transplanted cells can supply new neurons to replace injured ones, promote regeneration of axons and myelin sheath, modulate the inflammatory response, and thus promote recovery from traumatic injury of the CNS. Cellular transplantation is a promising potential method for the treatment of SCI.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 41023005, 21377145, 21321004)the State Environmental Protection Welfare Scientific Research Project (No. 201009026)
文摘12 perfluorinated compounds（PFCs） in human blood from workers in a textile mill in Shandong province and several barbershops in Tianjin were analyzed in this study. It was found that perfluorooctanesulfonate（PFOS） and perfluorooctanoate（PFOA） were the most prominent PFCs, with average concentrations of 5.73 mg/L and 5.46 mg/L for textile workers, and 2.55 mg/L and 2.84 mg/L for barbers.PFOS and perfluorohexanesulfonate（PFHxS） concentrations revealed a positive correlation in blood samples（p 〈 0.01）, and concentrations among PFOS, perfluorononanoic acid（PFNA） and perfluorodecanoic acid（PFDA） also revealed positive correlations（p 〈 0.01）. The influence of gender and age on PFC concentration in blood was also investigated, and the results showed that there was no statistically significant difference between the male and female samples, as well as in samples from people with different ages. Generally speaking, the textile workers
基金Supported by the National ‘863’ Project, No.2003AA2Z3245 and E-institute of Shanghai Municipal Education Commission, No. E03008
文摘AIM： To explore effects of huoxiangzhengqi liquid （HXZQ） on enteric mucosal immune responses in mice with Bacillus dysenteriae and Salmonella typhimurium induced diarrhea （BSD）. METHODS： BSD was induced in Balb/c mice by oral administration with Bacillus dysenteriae and Salmonella typhimurium. HXZQ was administrated from the day of diarrhea induction at dosages of 5.21 g/kg and 0.52 g/kg, respectively. The onset of diarrhea and lasting time were recorded. Peyer＇s patches and peripheral lymphocytes were prepared for flow cytometry, and levels of TNF-α in peripheral blood and enteric tissue homogenates were determined with ELISA. Student＇s t test was employed for statistics. RESULTS： Mice in BSD group started showing continuous diarrhea on the day of induction until the fourth day when they were sacrificed. Diarrhea in the mice of HXZQ high and low dose groups lasted for 36 and 54 h, respectively. There were more CD4^＋ and CD8^＋ cells in peripheral blood, fewer CD4^＋ cells in Peyer＇s patches in BSD mice compared to normal mice. Fewer CD4^＋ and CD8^＋ cells was shown in the mice in HXZQ high group compared to BSD mice. In Peyer＇s patch, there were more CD8^＋ cells in mice in HXZQ high and low dose groups and more CD4^＋ in mice in HXZQ high group. Higher levels of TNF-α in peripheral blood and intestinal tissue homogenates in BSD group were observed. Mice in HXZQ high group showed decreased levels of TNF-α in peripheral blood and enteric tissue homogenates. CONCLUSION： The immune regulation of CD4^＋ and CD8^＋ cells in Peyer＇s patch and suppression of TNF-α levels in enteric homogenates may partially explain the effect of HXZQ on improvement of BSD.
基金supported by the Guangxi Scholarship Fund of Guangxi Education Department,the Guangxi Med‑ical University Training Program for Distinguished Young Scholars,the Advanced Innovation Teams and Xinghu Scholars Program of Guangxi Medical University,the Guangxi Med‑ical and Health Key Discipline Construction Project,and the Science and Technology Plan Project of Qingxiu District,Nanning(Nos.2020037,2020038,2021007,2021010,and 2021012),China.
文摘Hepatocellular carcinoma(HCC)is one of the most common malignancies and a leading cause of cancer-related death worldwide.Surgery remains the primary and most successful therapy option for the treatment of early-and mid-stage HCCs,but the high heterogeneity of HCC renders prognostic prediction challenging.The construction of relevant prognostic models helps to stratify the prognosis of surgically treated patients and guide personalized clinical decision-making,thereby improving patient survival rates.Currently,the prognostic assessment of HCC is based on several commonly used staging systems,such as Tumor-Node-Metastasis(TNM),Cancer of the Liver Italian Program(CLIP),and Barcelona Clinic Liver Cancer(BCLC).Given the insufficiency of these staging systems and the aim to improve the accuracy of prognostic prediction,researchers have incorporated further prognostic factors,such as microvascular infiltration,and proposed some new prognostic models for HCC.To provide insights into the prospects of clinical oncology research,this review describes the commonly used HCC staging systems and new models proposed in recent years.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1804121 and 11304167)
文摘Cluster science as a bridge linking atomic molecular physics and condensed matter inspired the nanomaterials development in the past decades, ranging from the single-atom catalysis to ligand-protected noble metal clusters. The corresponding studies not only have been restricted to the search for the geometrical structures of clusters, but also have promoted the development of cluster-assembled materials as the building blocks. The CALYPSO cluster prediction method combined with other computational techniques have significantly stimulated the development of the cluster-based nanomaterials. In this review, we will summarize some good cases of cluster structure by CALYPSO method, which have also been successfully identified by the photoelectron spectra experiments. Beginning with the alkali-metal clusters, which serve as benchmarks, a series of studies are performed on the size-dependent elemental clusters which possess relatively high stability and interesting chemical physical properties. Special attentions are paid to the boron-based clusters because of their promising applications. The NbSi12 and BeB16 clusters, for example, are two classic representatives of the silicon-and boron-based clusters, which can be viewed as building blocks of nanotubes and borophene. This review offers a detailed description of the structural evolutions and electronic properties of medium-sized pure and doped clusters, which will advance fundamental knowledge of cluster-based nanomaterials and provide valuable information for further theoretical and experimental studies.
基金The financial support from Hunan Scientific Technology Projects(Grant Nos.2020WK2003 and 2019RS3007)National Natural Science Foundation of China(Grant Nos.52130408 and U1760202)is gratefully acknowledged.
文摘Interfacial heat transfer behavior between the molten steel and twin-rolls is a key issue in the strip casting process,and it has already attracted wide attention from industrial and academic communities of steel.The research methods and influencing factors on the interfacial heat transfer were summarized.Numerical simulation models,semi-industrial scale,and laboratory equipment have been developed in this field,and these methods were also improved by worldwide researchers based on the development of computer,automatic,and visual technologies.Coating properties,naturally deposited film,and casting parameters are the main factors which affect the heat transfer significantly.Although lots of research has been carried out,the internal relations among these influencing factors,interfacial heat transfer,and the quality of the strip are still worth to be further explored.Keywords Strip casting Interfacial heat transfer Simulation method Coating property Naturally deposited film Casting parameter.
基金The financial support for this work from the National Natural Science Foundation of China(52274342,52130408)the Hunan Scientific Technology Projects(Grant No.2020WK2003)+1 种基金the Natural Science Foundation of Hunan Province(2021JJ40731)the Postgraduate Scientific Research Innovation Project of Hunan Province(CX20220099)is gratefully acknowledged.
文摘Typical Q235 low-carbon steel samples with different hydrogen contents(0.0004,0.0008,and 0.0013 wt.%)were prepared by adjusting the environment humidity and moisture.The effects of hydrogen on interfacial heat transfer,contact behavior,and microstructure evolution were investigated using a novel droplet solidification technique.The results revealed that when the hydrogen content increases from 0.0004 to 0.0013 wt.%,the maximum heat flux between the molten steel and cooling substrate decreases from 8.01 to 6.19 MW/m^(2),and the total heat removed in the initial 2 s reduces from 10.30 to 8.27 MJ/m^(2).Moreover,the final contact angle between the molten steel and substrate increases from 103.741°to 113.697°,and the number of pores on the droplet bottom surface increases significantly from 21 to 210 with the increase in hydrogen.The surface roughness of the droplet bottom surface increases from 20.902 to 49.181 pm.In addition,the average grain size of the droplet increases from 14.778 to 33.548 pm with the increase in the hydrogen content.The interfacial contact condition becomes worse due to the escape of hydrogen from the steel matrix during the cooling process,which leads to the reduction in the interfacial heat transfer and the increase in the grain size.
基金This work was supported by the Belt and Road Special Foundation of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(No.2019nkzd01)National Natural Science Foundation of China(42077176).
文摘When groundwater pollution occurs,to come up with an efficient remediation plan,it is particularly important to collect information of contaminant source(location and source strength)and hydraulic conductivity field of the site accurately and quickly.However,the information can not be obtained by direct observation,and can only be derived from limited measurement data.Data assimilation of observations such as head and concentration is often used to estimate parameters of contaminant source.As for hydraulic conductivity field,especially for complex non-Gaussian field,it can be directly estimated by geostatistics method based on limited hard data,while the accuracy is often not high.Better estimation of hydraulic conductivity can be achieved by solving inverse groundwater problem.Therefore,in this study,the multi-point geostatistics method Quick Sampling(QS)is proposed and introduced for the first time and combined with the iterative local updating ensemble smoother(ILUES)to develop a new data assimilation framework QS-ILUES.It helps to solve the contaminant source parameters and non-Gaussian hydraulic conductivity field simultaneously by assimilating hydraulic head and pollutant concentration data.While the pilot points are utilized to reduce the dimension of hydraulic conductivity field,the influence of pilot points’layout and the ensemble size of ILUES algorithm on the inverse simulation results are further explored.
基金Australian Research Council Discovery Project(DP170103092)。
文摘In this study,the substructure formation in a multi-pass rolled aluminium single crystal{001}<110>was investigated by the crystal plasticity finite element model,and the predations were validated by experimental observations at both macro-and micro-scale.A finite element model for multi-pass rolling was developed to follow the real experimental rolling scheme,by which the through-thickness macroscopic subdivision was successfully predicted up to a 90%reduction.The macro-subdivision was featured by forming matrix bands through the thickness,and the deformation behaviours,in terms of slip activity,shear strain and crystal rotation,alternated between matrix bands.The development of matrix bands,stability of crystal orientations,and correlation between slip activity,shear strain and crystal rotation have been investigated.Another modelling method,Submodel,was used to exceedingly increase the mesh resolution in smaller regions of interest,and the experimentally observed microstructure,i.e.,micro-subdivision was explicitly and spatially revealed.Similar predictions were obtained in Submodels with different element sizes,which proves the feasibility of this method in predicting microstructure formation.It was found that the substructure formation by varying slip activity and crystal rotation between domains is energy favourable.The procedure of substructure formation was explained based on the predictions,three types of substructure have been identified,and the substructure formation was discussed.
文摘The development of practical methods for the direct and selective C(sp^(3))‒H functionalization of hydrocarbons is an attractive topic in synthetic chemistry.Although the radical‐mediated hydrogen atom transfer(HAT)process has shown considerable potential in such reactions,it still faces fundamental problems associated with reactivity and selectivity.Herein,we report a convenient and economic approach to site‐selective C(sp^(3))‒H sulfonylation via photo‐induced HAT catalysis.Employing a conjugated polycyclic quinone as a direct HAT photocatalyst,commercially available inorganic sulfinates as the sulfonylation source,copper triflate as an inexpensive oxidant,a variety of toluene derivatives and cycloalkanes were converted into biologically and synthetically interesting sulfone products under mild conditions.The mechanistic studies reveal that the reaction sequence involves direct HAT‐induced radical formation and a subsequent copper‐mediated organometallic process for the C‒S bond formation.This method offers an appealing opportunity to furnish high value‐added products from abundant hydrocarbon starting materials and inexpensive reagents.
基金supported by the National Key R&D Program of China(2020YFA0406103)the National Natural Science Foundation of China(U1932211,12205213)+2 种基金the Jiangsu Planned Projects for Postdoctoral Research Funds(7121453621)the Collaborative Innovation Center of Suzhou Nano Science&Technology,the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the 111 Project。
文摘Reconstruction during the catalytic process has been considered to play a key role for the performance.Here we report a RuNiPO based catalyst for efficient alkaline hydrogen evolution reaction(HER),which can benefit from a long-term reconstruction during HER for 10 h to continuously increase the performance.The final catalyst(e-RuNiPO)shows a huge morphology change from bulk sphere to highly exposed layered structure in the electrocatalysis process,and exhibits an interesting electronic structure modification with the electron transfer from Ru to Ni for better interfacial interaction and quick charge transfer.Due to the favorable morphology with more exposed active sites and the optimized electronic structure,the final catalyst can achieve an outstanding performance with only an overpotential of 15 mV at 10 mA cm^(-2)(with a good stability more than 100 h),even outperforming the performance of benchmark 20 wt%Pt/C catalyst(18 mV at 10 mA cm^(-2))by using a much lower Ru content.
基金Shanghai Academic Research Leader,China(No.20XD1420200)Shanghai Shuguang Program,China(No.18SG29)。
文摘Hydrophilic rare-earth up-conversion nanophosphors(UCNPs)with small sizes and a strong up-conversion luminescence have attracted much interest.Herein the simultaneous control of morphologies and the up-conversion luminescence intensities was reported for NaYF_(4)∶Yb/Er nanophosphors by a facile hydrothermal procedure with different surfactants.With the change of the surfactants from polyvinylpyrrolidone(PVP)to sodium citrate(CIT),edetate disodium(EDTA)or sodium dodecyl benzenesulfonate(SDBS),the morphology of NaYF_(4)∶Yb/Er nanophosphors transformed from nanoparticles with a diameter of about 70.0 nm to hexagonal nanoblocks with a thickness of about 125.0 nm and a length of about 240.0 nm,nanorods with a diameter of about 700.0 nm and a length of about 2.6μm,or nanowires with a diameter of 250.0 nm and a length of about 3.2μm.Simultaneously,their up-conversion luminescence intensity went down gradually under laser irradiation at a wavelength of 980 nm due to the increase of photobleaching.PVP-capped NaYF_(4)∶Yb/Er nanoparticles exhibited the smallest size and the strongest up-conversion luminescence intensity.Biological experiment results revealed that NaYF_(4)∶Yb/Er nanophosphors exhibited a high biocompatibility and could be used as biological labels with a perfect signal-to-noise ratio for cancer cell imaging.
基金supported by Shanghai Science and Technology Development Foundation(054119558)
文摘Spinal cord injury（SCI） is a severe trauma to the central nervous system（CNS）. This article reviews recent advances in cellular transplantation to treat SCI. Transplanted cells can supply new neurons to replace injured ones, promote regeneration of axons and myelin sheath, modulate the inflammatory response, and thus promote recovery from traumatic injury of the CNS. Cellular transplantation is a promising potential method for the treatment of SCI.
