Crohn’s disease(CD)is caused by immune,environmental,and genetic factors.It can involve the entire gastrointestinal tract,and although its prevalence is rapidly increasing its etiology remains unclear.Emerging biolog...Crohn’s disease(CD)is caused by immune,environmental,and genetic factors.It can involve the entire gastrointestinal tract,and although its prevalence is rapidly increasing its etiology remains unclear.Emerging biological and small-molecule drugs have advanced the treatment of CD;however,a considerable proportion of patients are non-responsive to all known drugs.To achieve a breakthrough in this field,innovations that could guide the further development of effective therapies are of utmost urgency.In this review,we first propose the innovative concept of pan-lymphatic dysfunction for the general distribution of lymphatic dysfunction in various diseases,and suggest that CD is the intestinal manifestation of pan-lymphatic dysfunction based on basic and clinical preliminary data.The supporting evidence is fully summarized,including the existence of lymphatic system dysfunction,recognition of the inside-out model,disorders of immune cells,changes in cell plasticity,partial overlap of the underlying mechanisms,and common gut-derived fatty and bile acid metabolism.Another benefit of this novel concept is that it proposes adopting the zebrafish model for studying intestinal diseases,especially CD,as this model is good at presenting and mimicking lymphatic dysfunction.More importantly,the ensuing focus on improving lymphatic function may lead to novel and promising therapeutic strategies for CD.展开更多
Dajianzhong decoction(DJZD)is one of the traditional herbal prescriptions originated from Synopsis of Golden Chamber,which clinically used for the treatment of various gastrointestinal(GI)disease.This paper was aimed ...Dajianzhong decoction(DJZD)is one of the traditional herbal prescriptions originated from Synopsis of Golden Chamber,which clinically used for the treatment of various gastrointestinal(GI)disease.This paper was aimed to provide a systematic review on the phytochemistry of DJZD and its therapeutic potential for GI disease and the mechanism.Finally,the possible development and perspectives for future research on this prescription were also discussed.To date,over 60 compounds have been identified form DJZD,including unsaturated fatty acid,saponins,and polyphenols,with hydroxy-sanshool and ginsenoside compounds as the predominant ones.DJZD possessed widely pharmacological activities on the GI disease from the Eastern Han Dynasty to the present,such as intestinal obstruction,colitis,and irritable bowel syndrome.Especially for the intestinal obstruction,it had demonstrated the efficacy of DJZD treatment for relief of postoperative ileus in patients undergoing surgery for GI cancer.The detailed mechanism was mainly related with NF-ᴋB signaling pathway.However,further research elucidating the protective effects of DJZD on GI disease,exploring new clinical effects,as well as establishing criteria for quality control for DJZD should be studied.展开更多
BACKGROUND Conventional Crohn’s disease(CD)treatments are supportive rather than curative and have serious side effects.Adipose-derived mesenchymal stem cells(ADSCs)have been gradually applied to treat various diseas...BACKGROUND Conventional Crohn’s disease(CD)treatments are supportive rather than curative and have serious side effects.Adipose-derived mesenchymal stem cells(ADSCs)have been gradually applied to treat various diseases.The therapeutic effect and underlying mechanism of ADSCs on CD are still not clear.AIM To investigate the effect of ADSC administration on CD and explore the potential mechanisms.METHODS Wistar rats were administered with 2,4,6-trinitrobenzene sulfonic acid(TNBS)to establish a rat model of CD,followed by tail injections of green fluorescent protein(GFP)-modified ADSCs.Flow cytometry,qRT-PCR,and Western blot were used to detect changes in the Wnt signaling pathway,T cell subtypes,and their related cytokines.RESULTS The isolated cells showed the characteristics of ADSCs,including spindle-shaped morphology,high expression of CD29,CD44,and CD90,low expression of CD34 and CD45,and osteogenic/adipogenic ability.ADSC therapy markedly reduced disease activity index and ameliorated colitis severity in the TNBS-induced rat model of CD.Furthermore,serum anti-sacchromyces cerevisiae antibody and panti-neutrophil cytoplasmic antibody levels were significantly reduced in ADSCtreated rats.Mechanistically,the GFP-ADSCs were colocalized with intestinal epithelial cells(IECs)in the CD rat model.GFP-ADSC delivery significantly antagonized TNBS-induced increased canonical Wnt pathway expression,decreased noncanonical Wnt signaling pathway expression,and increased apoptosis rates and protein level of cleaved caspase-3 in rats.In addition,ADSCs attenuated TNBS-induced abnormal inflammatory cytokine production,disturbed T cell subtypes,and their related markers in rats.CONCLUSION Successfully isolated ADSCs show therapeutic effects in CD by regulating IEC proliferation,the Wnt signaling pathway,and T cell immunity.展开更多
Grand canonical Monte Carlo simulation(GCMCs)is utilized for studying hydrogen storage gravimetric density by pha-graphene at different metal densities,temperatures and pressures.It is demonstrated that the optimum ad...Grand canonical Monte Carlo simulation(GCMCs)is utilized for studying hydrogen storage gravimetric density by pha-graphene at different metal densities,temperatures and pressures.It is demonstrated that the optimum adsorbent location for Li atoms is the center of the seven-membered ring of pha-graphene.The binding energy of Li-decorated phagraphene is larger than the cohesive energy of Li atoms,implying that Li can be distributed on the surface of pha-graphene without forming metal clusters.We fitted the force field parameters of Li and C atoms at different positions and performed GCMCs to study the absorption capacity of H_(2).The capacity of hydrogen storage was studied by the differing density of Li decoration.The maximum hydrogen storage capacity of 4Li-decorated pha-graphene was 15.88 wt%at 77 K and100 bar.The enthalpy values of adsorption at the three densities are in the ideal range of 15 kJ·mol^(-1)-25 kJ·mol^(-1).The GCMC results at different pressures and temperatures show that with the increase in Li decorative density,the hydrogen storage gravimetric ratio of pha-graphene decreases but can reach the 2025 US Department of Energy's standard(5.5 wt%).Therefore,pha-graphene is considered to be a potential hydrogen storage material.展开更多
BACKGROUND Obesity plays a vital role in the occurrence and development of non-alcoholic steatohepatitis(NASH).However,the underlining mechanism is still unclear,where adipose tissue(AT)derived exosomes may actively p...BACKGROUND Obesity plays a vital role in the occurrence and development of non-alcoholic steatohepatitis(NASH).However,the underlining mechanism is still unclear,where adipose tissue(AT)derived exosomes may actively participate.MicroRNAs(miRNAs)are commonly secreted from exosomes for cell communication.Though the regulation of miR-103 on insulin sensitivity has been reported,the specific role of AT-derived exosomes miR-103 in NASH is still vague and further investigation may provide novel therapeutic choices.AIM To determine the specific role of AT-derived exosomes miR-103 in developing NASH through various methods.METHODS The expression levels of miR-103 in the AT-derived exosomes and livers were detected and compared between NASH mice and control.The effect of miR-103 on NASH progression was also explored by antagonizing miR-103,including steatosis and inflammation degree changes.The interaction between miR-103 and the autophagy-related gene phosphatase and tensin homolog(PTEN)was confirmed by dual-luciferase reporter assay.The role of the interaction between miR-103 and PTEN on autophagy was verified in NASH-like cells.Finally,the effects of miR-103 from adipose-derived exosomes on NASH and autophagy were analyzed through animal experiments.RESULTS The expression of miR-103 was increased in NASH mice,compared to the control,and inhibition of miR-103 could alleviate NASH.The results of the dual-luciferase reporter assay showed miR-103 could interact with PTEN.MiR-103-anta decreased p-AMPKa,p-mammalian target of rapamycin(mTOR),and p62 but increased the protein levels of PTEN and LC3-II/I and the number of autophagosomes in NASH mice.Similar results were also observed in NASH-like cells,and further experiments showed PTEN silencing inhibited the effect of miR-103-anta.AT derivedexosome miR-103 aggravated NASH and increased the expressions of p-AMPKa,p-mTOR,and p62 but decreased the protein levels of PTEN and LC3-II/I and the number of autophagosomes in mice.CONCLUSION AT derived-exosome increased the levels of miR-103 in the liver,and miR-103 aggravated NASH.Mechanically,miR-103 could interact with PTEN and inhibit autophagy.展开更多
A facile approach was developed for the synthesis of polycrystalline palladium nanoparticles(Pd NPs)by using tannic acid(TA) as green reagent and stabilizer in a 30 ℃ water bath. The size of Pd NPs can be tuned in a ...A facile approach was developed for the synthesis of polycrystalline palladium nanoparticles(Pd NPs)by using tannic acid(TA) as green reagent and stabilizer in a 30 ℃ water bath. The size of Pd NPs can be tuned in a range of 10–60 nm simply by adjusting the concentration of Pd precursor. The catalytic activity and stability of the as-obtained Pd NPs toward formic acid oxidation were analyzed. It is found that these Pd NPs with different sizes exhibit size-dependent and enhanced formic acid oxidation performance compared to the commercial Pd black catalyst. It should be noted that the Pd catalysts with an average size of 24 nm demonstrate the best catalytic activity and stability among the other prepared Pd NPs, which can be ascribed to its larger electrochemical surface area(ECSA)and polycrystalline structure with defects.展开更多
Self-organized titanium dioxide(TiO_(2))nanotubes,which are prepared by electrochemical anodizing,have been widely researched as promising anodes for Liion batteries.Both nanotubular morphology and bulk structure of T...Self-organized titanium dioxide(TiO_(2))nanotubes,which are prepared by electrochemical anodizing,have been widely researched as promising anodes for Liion batteries.Both nanotubular morphology and bulk structure of TiO_(2)nanotubes can be easily changed by adjusting the anodizing and annealing parameters.This is provided to investigate different phenomena by selectively adjusting a specific parameter of the Li^(+)insertion mechanism.In this paper,we reviewed how the morphology and crystallography of TiO_(2)nano tubes influence the electrochemical performance of Li^(+)batteries.In particular,electrochemical performances of amorphous and anatase titanium dioxide nanotube anodes were compared in detail.As we all know,TiO_(2)nanotube anodes have the advantages of nontoxicity,good stability,high safety and large specific surface area,in lithium-ion batteries.However,they suffer from poor electronic conductivity,inferior ion diffusivity and low theoretical capacity(335 mAh·g^(-1)),which limit their practical application.Generally,there are two ways to overcome the shortcomings of titanium dioxide nanotube anodes,including doping and synthesis composites.The achievements and existing problems associated with doped TiO_(2)nanotube anodes and composite material anodes are summarized in the present review.Based on the analysis of lithium insertion mechanism of titanium dioxide nanotube electrodes,the prospects and possible research directions of TiO_(2)anodes in lithiumion batteries are discussed.展开更多
High entropy alloy(HEA)exhibits potential water-splitting properties but are limited by the high energy consumption from preparation.Moreover,the complex atomic distribution endows the electronic structure regulation ...High entropy alloy(HEA)exhibits potential water-splitting properties but are limited by the high energy consumption from preparation.Moreover,the complex atomic distribution endows the electronic structure regulation of HEA to remain challenging.Herein,the nanoporous NiCuMnCoFe(np-NCMCF)HEA was prepared by the high-energy ball milling coupled with de-alloying method.The introduced Fe markedly increases the proportion of Ni^(3+)and Co^(3+).展开更多
Carbon nanofibers(CNFs)have been extensively studied as anode materials for sodium-ion batteries due to their high conductivity,large aspect ratio and good electrochemical stability.The low specific capacity and low f...Carbon nanofibers(CNFs)have been extensively studied as anode materials for sodium-ion batteries due to their high conductivity,large aspect ratio and good electrochemical stability.The low specific capacity and low first cycle efficiency of CNFs,however,have hindered its practical application.Herein,we present a facile strategy to synthesize a novel CNFs decorated with Cu/CuO nanoparticles(Cu-CNFs)using magnetron sputtering method.Cu/CuO nanoparticles were uniformly distributed on the surface of CNFs.According to the density functional theory(DFT)calculation,Cu/CuO nanoparticles d-orbitals and CNFs p-orbitals present hybridization states,and the Na~+adsorption energy of the modified CNFs decreases from-2.14 to-2.97 eV.The Cu-CNFs composites exhibit excellent sodium storage properties,presenting a desirable initial Coulombic efficiency of 76%and a high specific reversible capacity of 300 mAh·g^(-1)at 0.1 A·g^(-1)after 400 cycles.Cu-CNFs anode has excellent cycling stability under high current density,maintaining a high capacity of 150 mAh·g^(-1)at 1 A·g^(-1)after 6000 cycles.Using magnetron sputtering to regulate the electronic structure provides a new thought for improving the electrochemical performance of carbon materials.展开更多
The vortex induced vibration(VIV)of marine risers has been investigated by many researchers in experimental studies of a straight flexible riser model as well as a rigid cylinder to reveal the dynamic response charact...The vortex induced vibration(VIV)of marine risers has been investigated by many researchers in experimental studies of a straight flexible riser model as well as a rigid cylinder to reveal the dynamic response characteristic and the mechanics behind it.However,due to the limitation of experimental apparatus,very few studies are about the VIV of a steel catenary riser(SCR)which is with a complex geometry.To investigate the VTV features and to further develop the corresponding numerical predictions of a SCR under steady current,a large-scale model test of a SCR was towed in an ocean basin at various speeds.Fiber Bragg grating strain sensors are instrumented on the riser model to measure both in-plane and out-of-plane responses.The characteristics of oscillating amplitude and dominating frequency response,the phenomenon of mode competition and travelling wave and the fatigue damage of the steel catenary riser in inline and cross-flow direction under steady current are analyzed.展开更多
A novel copolymer with fluorescence properties in mesoporous silica SBA-15 was prepared via a combination of surface-initiated reversible addition-fragmentation chain transfer(RAFT) polymerization and "click" chem...A novel copolymer with fluorescence properties in mesoporous silica SBA-15 was prepared via a combination of surface-initiated reversible addition-fragmentation chain transfer(RAFT) polymerization and "click" chemistry.A sufficient amount of peroxide groups were introduced into mesoporous silica SBA-15 channel pores and were further used to initiate the RAFT polymerization of styrene and 4-vinylbenzyl azide,resulting in SBA-15 supported polystyrene-co-poly(4-vinylbenzyl azide) copolymer(PS-co-PVBA/SBA-15) hybrid material.The samples were characterized by Fourier transform infrared spectroscopy(FT-IR),transmission electron microscopy(TEM),thermogravimetry analysis(TGA),N_2 adsorption-desorption isotherms and X-ray diffraction(XRD),respectively.The results show that the styrene and 4-vinylbenzyl azide had copolymerized inside mesoporous silica SBA-15.Subsequently,Npropargyl-carbazole(PC) was connected to PS-co-PVBA/SBA-15 hybrid material via "click" reaction,resulting in PS-co-PVBC/SBA-15 with carbazole side groups hybrid material.The fluorescence spectrum is dominated by a broad band from 350 nm to 400 nm in narrow region and the maximum peak is 362 nm,indicating the characteristic absorption of the carbazole group of PS-co-PVBC/SBA-15 hybrid material.展开更多
Three-dimensional flower-like nanomaterials have wide application due to the large specific surface area.In this letter,the morphology of octadecylamine(ODA) from several common solvents is studied and it is found t...Three-dimensional flower-like nanomaterials have wide application due to the large specific surface area.In this letter,the morphology of octadecylamine(ODA) from several common solvents is studied and it is found that from the chloroform and acetone solution,ODA assembles into petal-like structure,which further forms the spherical or flower-like architecture.Furthermore,the composite materials incorporated reduced graphene oxide(rGO) and ODA could well keep the flower-shaped structure of ODA.XRD results show that the introduction of graphene has little influence on the structure of ODA and contact angle test indicates good hydrophobic performance of the rGO/ODA material.展开更多
The layer-by-layer assembly of polyethyleneimine and carbon nanotubes is carried out through the electrostatic interactions on colloidal polystyrene templates. The successful spherical growth of polyethyleneimine/carb...The layer-by-layer assembly of polyethyleneimine and carbon nanotubes is carried out through the electrostatic interactions on colloidal polystyrene templates. The successful spherical growth of polyethyleneimine/carbon nanotube multilayers could be investigated by SEM. The subsequent in situ preparation and deposition of gold nanoparticles on the core–shell composites could yield novel microsphere complexes, which are characterized by SEM, TEM, EDX and XRD. The functional hierarchical microspheres with gold nanoparticles exhibit good catalytic activity in the reaction of reducing 4-nitrophenol to 4-aminophenol.展开更多
The layer-by-layer assembly of graphene oxide and diazoresin is carried out via the electrostatic and hydrogen bond interactions on planar substrates and colloidal templates.The successful planar and spherical growth ...The layer-by-layer assembly of graphene oxide and diazoresin is carried out via the electrostatic and hydrogen bond interactions on planar substrates and colloidal templates.The successful planar and spherical growth of multilayer could be investigated by UV-vis spectrophotometry and scanning electron microscopy,respectively.Subsequent UV irradiation or heating would convert the ionic bonds and hydrogen bonds to covalent bands,which significantly improves the stability of the multilayer composite against solvent etching.For the cross-linked core-shell composites,the template cores could be removed by dissolution and hollow microspheres are obtained.展开更多
文摘Crohn’s disease(CD)is caused by immune,environmental,and genetic factors.It can involve the entire gastrointestinal tract,and although its prevalence is rapidly increasing its etiology remains unclear.Emerging biological and small-molecule drugs have advanced the treatment of CD;however,a considerable proportion of patients are non-responsive to all known drugs.To achieve a breakthrough in this field,innovations that could guide the further development of effective therapies are of utmost urgency.In this review,we first propose the innovative concept of pan-lymphatic dysfunction for the general distribution of lymphatic dysfunction in various diseases,and suggest that CD is the intestinal manifestation of pan-lymphatic dysfunction based on basic and clinical preliminary data.The supporting evidence is fully summarized,including the existence of lymphatic system dysfunction,recognition of the inside-out model,disorders of immune cells,changes in cell plasticity,partial overlap of the underlying mechanisms,and common gut-derived fatty and bile acid metabolism.Another benefit of this novel concept is that it proposes adopting the zebrafish model for studying intestinal diseases,especially CD,as this model is good at presenting and mimicking lymphatic dysfunction.More importantly,the ensuing focus on improving lymphatic function may lead to novel and promising therapeutic strategies for CD.
基金supported by National Natural Science Foundation of China(No.82304972)Shaanxi Provincial Department of Education(No.23JK0413)the Shaanxi Provincial Department of Science and Technology program(No.2024SF-YBXM-483).
文摘Dajianzhong decoction(DJZD)is one of the traditional herbal prescriptions originated from Synopsis of Golden Chamber,which clinically used for the treatment of various gastrointestinal(GI)disease.This paper was aimed to provide a systematic review on the phytochemistry of DJZD and its therapeutic potential for GI disease and the mechanism.Finally,the possible development and perspectives for future research on this prescription were also discussed.To date,over 60 compounds have been identified form DJZD,including unsaturated fatty acid,saponins,and polyphenols,with hydroxy-sanshool and ginsenoside compounds as the predominant ones.DJZD possessed widely pharmacological activities on the GI disease from the Eastern Han Dynasty to the present,such as intestinal obstruction,colitis,and irritable bowel syndrome.Especially for the intestinal obstruction,it had demonstrated the efficacy of DJZD treatment for relief of postoperative ileus in patients undergoing surgery for GI cancer.The detailed mechanism was mainly related with NF-ᴋB signaling pathway.However,further research elucidating the protective effects of DJZD on GI disease,exploring new clinical effects,as well as establishing criteria for quality control for DJZD should be studied.
基金National Natural Science Foundation of China,No.81770574,No.81600414,and No.81600447.
文摘BACKGROUND Conventional Crohn’s disease(CD)treatments are supportive rather than curative and have serious side effects.Adipose-derived mesenchymal stem cells(ADSCs)have been gradually applied to treat various diseases.The therapeutic effect and underlying mechanism of ADSCs on CD are still not clear.AIM To investigate the effect of ADSC administration on CD and explore the potential mechanisms.METHODS Wistar rats were administered with 2,4,6-trinitrobenzene sulfonic acid(TNBS)to establish a rat model of CD,followed by tail injections of green fluorescent protein(GFP)-modified ADSCs.Flow cytometry,qRT-PCR,and Western blot were used to detect changes in the Wnt signaling pathway,T cell subtypes,and their related cytokines.RESULTS The isolated cells showed the characteristics of ADSCs,including spindle-shaped morphology,high expression of CD29,CD44,and CD90,low expression of CD34 and CD45,and osteogenic/adipogenic ability.ADSC therapy markedly reduced disease activity index and ameliorated colitis severity in the TNBS-induced rat model of CD.Furthermore,serum anti-sacchromyces cerevisiae antibody and panti-neutrophil cytoplasmic antibody levels were significantly reduced in ADSCtreated rats.Mechanistically,the GFP-ADSCs were colocalized with intestinal epithelial cells(IECs)in the CD rat model.GFP-ADSC delivery significantly antagonized TNBS-induced increased canonical Wnt pathway expression,decreased noncanonical Wnt signaling pathway expression,and increased apoptosis rates and protein level of cleaved caspase-3 in rats.In addition,ADSCs attenuated TNBS-induced abnormal inflammatory cytokine production,disturbed T cell subtypes,and their related markers in rats.CONCLUSION Successfully isolated ADSCs show therapeutic effects in CD by regulating IEC proliferation,the Wnt signaling pathway,and T cell immunity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11904175,11804169,and 11804165)the Graduate Innovation Project of Jiangsu Province,China(Grant No.KYCX210700)。
文摘Grand canonical Monte Carlo simulation(GCMCs)is utilized for studying hydrogen storage gravimetric density by pha-graphene at different metal densities,temperatures and pressures.It is demonstrated that the optimum adsorbent location for Li atoms is the center of the seven-membered ring of pha-graphene.The binding energy of Li-decorated phagraphene is larger than the cohesive energy of Li atoms,implying that Li can be distributed on the surface of pha-graphene without forming metal clusters.We fitted the force field parameters of Li and C atoms at different positions and performed GCMCs to study the absorption capacity of H_(2).The capacity of hydrogen storage was studied by the differing density of Li decoration.The maximum hydrogen storage capacity of 4Li-decorated pha-graphene was 15.88 wt%at 77 K and100 bar.The enthalpy values of adsorption at the three densities are in the ideal range of 15 kJ·mol^(-1)-25 kJ·mol^(-1).The GCMC results at different pressures and temperatures show that with the increase in Li decorative density,the hydrogen storage gravimetric ratio of pha-graphene decreases but can reach the 2025 US Department of Energy's standard(5.5 wt%).Therefore,pha-graphene is considered to be a potential hydrogen storage material.
基金the Natural Science Foundation of Zhejiang Province,No.LZ21H030002。
文摘BACKGROUND Obesity plays a vital role in the occurrence and development of non-alcoholic steatohepatitis(NASH).However,the underlining mechanism is still unclear,where adipose tissue(AT)derived exosomes may actively participate.MicroRNAs(miRNAs)are commonly secreted from exosomes for cell communication.Though the regulation of miR-103 on insulin sensitivity has been reported,the specific role of AT-derived exosomes miR-103 in NASH is still vague and further investigation may provide novel therapeutic choices.AIM To determine the specific role of AT-derived exosomes miR-103 in developing NASH through various methods.METHODS The expression levels of miR-103 in the AT-derived exosomes and livers were detected and compared between NASH mice and control.The effect of miR-103 on NASH progression was also explored by antagonizing miR-103,including steatosis and inflammation degree changes.The interaction between miR-103 and the autophagy-related gene phosphatase and tensin homolog(PTEN)was confirmed by dual-luciferase reporter assay.The role of the interaction between miR-103 and PTEN on autophagy was verified in NASH-like cells.Finally,the effects of miR-103 from adipose-derived exosomes on NASH and autophagy were analyzed through animal experiments.RESULTS The expression of miR-103 was increased in NASH mice,compared to the control,and inhibition of miR-103 could alleviate NASH.The results of the dual-luciferase reporter assay showed miR-103 could interact with PTEN.MiR-103-anta decreased p-AMPKa,p-mammalian target of rapamycin(mTOR),and p62 but increased the protein levels of PTEN and LC3-II/I and the number of autophagosomes in NASH mice.Similar results were also observed in NASH-like cells,and further experiments showed PTEN silencing inhibited the effect of miR-103-anta.AT derivedexosome miR-103 aggravated NASH and increased the expressions of p-AMPKa,p-mTOR,and p62 but decreased the protein levels of PTEN and LC3-II/I and the number of autophagosomes in mice.CONCLUSION AT derived-exosome increased the levels of miR-103 in the liver,and miR-103 aggravated NASH.Mechanically,miR-103 could interact with PTEN and inhibit autophagy.
基金financially supported by the National Natural Science Foundation of China (Nos. 51371119 and 51571151)
文摘A facile approach was developed for the synthesis of polycrystalline palladium nanoparticles(Pd NPs)by using tannic acid(TA) as green reagent and stabilizer in a 30 ℃ water bath. The size of Pd NPs can be tuned in a range of 10–60 nm simply by adjusting the concentration of Pd precursor. The catalytic activity and stability of the as-obtained Pd NPs toward formic acid oxidation were analyzed. It is found that these Pd NPs with different sizes exhibit size-dependent and enhanced formic acid oxidation performance compared to the commercial Pd black catalyst. It should be noted that the Pd catalysts with an average size of 24 nm demonstrate the best catalytic activity and stability among the other prepared Pd NPs, which can be ascribed to its larger electrochemical surface area(ECSA)and polycrystalline structure with defects.
基金the National Natural Science Foundation of China(No.61376017)the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(No.CUSFDH-D-2020094)the Shanghai Sailing Program(No.17YF1400600)。
文摘Self-organized titanium dioxide(TiO_(2))nanotubes,which are prepared by electrochemical anodizing,have been widely researched as promising anodes for Liion batteries.Both nanotubular morphology and bulk structure of TiO_(2)nanotubes can be easily changed by adjusting the anodizing and annealing parameters.This is provided to investigate different phenomena by selectively adjusting a specific parameter of the Li^(+)insertion mechanism.In this paper,we reviewed how the morphology and crystallography of TiO_(2)nano tubes influence the electrochemical performance of Li^(+)batteries.In particular,electrochemical performances of amorphous and anatase titanium dioxide nanotube anodes were compared in detail.As we all know,TiO_(2)nanotube anodes have the advantages of nontoxicity,good stability,high safety and large specific surface area,in lithium-ion batteries.However,they suffer from poor electronic conductivity,inferior ion diffusivity and low theoretical capacity(335 mAh·g^(-1)),which limit their practical application.Generally,there are two ways to overcome the shortcomings of titanium dioxide nanotube anodes,including doping and synthesis composites.The achievements and existing problems associated with doped TiO_(2)nanotube anodes and composite material anodes are summarized in the present review.Based on the analysis of lithium insertion mechanism of titanium dioxide nanotube electrodes,the prospects and possible research directions of TiO_(2)anodes in lithiumion batteries are discussed.
基金financially supported by the National Natural Science Foundation of China (Nos.52271011 and 52102291)。
文摘High entropy alloy(HEA)exhibits potential water-splitting properties but are limited by the high energy consumption from preparation.Moreover,the complex atomic distribution endows the electronic structure regulation of HEA to remain challenging.Herein,the nanoporous NiCuMnCoFe(np-NCMCF)HEA was prepared by the high-energy ball milling coupled with de-alloying method.The introduced Fe markedly increases the proportion of Ni^(3+)and Co^(3+).
基金financially supported by the National Natural Science Foundation of China (Nos.52271011 and 52102291)。
文摘Carbon nanofibers(CNFs)have been extensively studied as anode materials for sodium-ion batteries due to their high conductivity,large aspect ratio and good electrochemical stability.The low specific capacity and low first cycle efficiency of CNFs,however,have hindered its practical application.Herein,we present a facile strategy to synthesize a novel CNFs decorated with Cu/CuO nanoparticles(Cu-CNFs)using magnetron sputtering method.Cu/CuO nanoparticles were uniformly distributed on the surface of CNFs.According to the density functional theory(DFT)calculation,Cu/CuO nanoparticles d-orbitals and CNFs p-orbitals present hybridization states,and the Na~+adsorption energy of the modified CNFs decreases from-2.14 to-2.97 eV.The Cu-CNFs composites exhibit excellent sodium storage properties,presenting a desirable initial Coulombic efficiency of 76%and a high specific reversible capacity of 300 mAh·g^(-1)at 0.1 A·g^(-1)after 400 cycles.Cu-CNFs anode has excellent cycling stability under high current density,maintaining a high capacity of 150 mAh·g^(-1)at 1 A·g^(-1)after 6000 cycles.Using magnetron sputtering to regulate the electronic structure provides a new thought for improving the electrochemical performance of carbon materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.51490674,51825903).
文摘The vortex induced vibration(VIV)of marine risers has been investigated by many researchers in experimental studies of a straight flexible riser model as well as a rigid cylinder to reveal the dynamic response characteristic and the mechanics behind it.However,due to the limitation of experimental apparatus,very few studies are about the VIV of a steel catenary riser(SCR)which is with a complex geometry.To investigate the VTV features and to further develop the corresponding numerical predictions of a SCR under steady current,a large-scale model test of a SCR was towed in an ocean basin at various speeds.Fiber Bragg grating strain sensors are instrumented on the riser model to measure both in-plane and out-of-plane responses.The characteristics of oscillating amplitude and dominating frequency response,the phenomenon of mode competition and travelling wave and the fatigue damage of the steel catenary riser in inline and cross-flow direction under steady current are analyzed.
基金supported by the National Natural Science Foundation of China(No.21203085)Promotive Research Fund for Young and Middle-aged Scientists of Shandong Province in China(doctor fund,Nos.BS2011CL011,BS2011CL012 and BS2012CL009)
文摘A novel copolymer with fluorescence properties in mesoporous silica SBA-15 was prepared via a combination of surface-initiated reversible addition-fragmentation chain transfer(RAFT) polymerization and "click" chemistry.A sufficient amount of peroxide groups were introduced into mesoporous silica SBA-15 channel pores and were further used to initiate the RAFT polymerization of styrene and 4-vinylbenzyl azide,resulting in SBA-15 supported polystyrene-co-poly(4-vinylbenzyl azide) copolymer(PS-co-PVBA/SBA-15) hybrid material.The samples were characterized by Fourier transform infrared spectroscopy(FT-IR),transmission electron microscopy(TEM),thermogravimetry analysis(TGA),N_2 adsorption-desorption isotherms and X-ray diffraction(XRD),respectively.The results show that the styrene and 4-vinylbenzyl azide had copolymerized inside mesoporous silica SBA-15.Subsequently,Npropargyl-carbazole(PC) was connected to PS-co-PVBA/SBA-15 hybrid material via "click" reaction,resulting in PS-co-PVBC/SBA-15 with carbazole side groups hybrid material.The fluorescence spectrum is dominated by a broad band from 350 nm to 400 nm in narrow region and the maximum peak is 362 nm,indicating the characteristic absorption of the carbazole group of PS-co-PVBC/SBA-15 hybrid material.
基金supported by the Natural Science Foundation of China(Nos.21173266 and 21473250)the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(No.11XNJ021)
文摘Three-dimensional flower-like nanomaterials have wide application due to the large specific surface area.In this letter,the morphology of octadecylamine(ODA) from several common solvents is studied and it is found that from the chloroform and acetone solution,ODA assembles into petal-like structure,which further forms the spherical or flower-like architecture.Furthermore,the composite materials incorporated reduced graphene oxide(rGO) and ODA could well keep the flower-shaped structure of ODA.XRD results show that the introduction of graphene has little influence on the structure of ODA and contact angle test indicates good hydrophobic performance of the rGO/ODA material.
基金supported by the National Natural Science Foundation of China (Nos. 21173266 and 21473250)the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China (Nos. 11XNJ021 and 15XNLQ04)
文摘The layer-by-layer assembly of polyethyleneimine and carbon nanotubes is carried out through the electrostatic interactions on colloidal polystyrene templates. The successful spherical growth of polyethyleneimine/carbon nanotube multilayers could be investigated by SEM. The subsequent in situ preparation and deposition of gold nanoparticles on the core–shell composites could yield novel microsphere complexes, which are characterized by SEM, TEM, EDX and XRD. The functional hierarchical microspheres with gold nanoparticles exhibit good catalytic activity in the reaction of reducing 4-nitrophenol to 4-aminophenol.
基金supported by the Natural Science Foundation of China(Nos.21173266 and 21473250)the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(No.11XNJ021)
文摘The layer-by-layer assembly of graphene oxide and diazoresin is carried out via the electrostatic and hydrogen bond interactions on planar substrates and colloidal templates.The successful planar and spherical growth of multilayer could be investigated by UV-vis spectrophotometry and scanning electron microscopy,respectively.Subsequent UV irradiation or heating would convert the ionic bonds and hydrogen bonds to covalent bands,which significantly improves the stability of the multilayer composite against solvent etching.For the cross-linked core-shell composites,the template cores could be removed by dissolution and hollow microspheres are obtained.