Electronic-state modulation strategy offers great potential in designing RuO_(2)-based bifunctionalelectrocatalysts for rechargeable Zn-air batteries(ZABs).Various three-dimensional(3D)transition metal oxides are atte...Electronic-state modulation strategy offers great potential in designing RuO_(2)-based bifunctionalelectrocatalysts for rechargeable Zn-air batteries(ZABs).Various three-dimensional(3D)transition metal oxides are attempted to couple with RuO_(2)for constructing an appropriate Ru—O—M interface.This work aims to construct Co_(3)O_(4)-RuO_(2)heterostructures on carbon sheets(Co_(3)O_(4)/RuO_(2)/NCNS)for boosting electronic transfer and regulation.Experiments and theoretical calculations identify the electronic transfer from Co_(3)O_(4)to RuO_(2)that modulates the electronic structure of metal surfaces/interfaces.Specifically,it leads to the increase in Co3+content,electron-rich state at RuO_(2)surface and electronic accumulation at interfaces.Moreover,this electronic-state modulation optimizes the d-band center in Co_(3)O_(4)/RuO_(2)that lowers the reaction barriers and endows interfaces as the biggest contributor to oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)performance,The Co_(3)O_(4)/RuO_(2)/NCNS shows a quite low potential difference of 0.62 V and remarkable durability for ORR/OER.Co_(3)O_(4)/RuO_(2)/NCNS-assembled ZABs exhibit an excellent specific capacity of 818.3 mA h g^(-1)and a superior lifespan over 750 h.展开更多
It is desirable to fabricate materials with adjustable physical properties that can be used in different industrial applications.Since the property of a material is highly dependent on its inner structure,the understa...It is desirable to fabricate materials with adjustable physical properties that can be used in different industrial applications.Since the property of a material is highly dependent on its inner structure,the understanding of structure–property correlation is critical to the design of engineering materials.3D printing appears as a mature method to effectively produce micro-structured materials.In this work,we created different stainless-steel microstructures by adjusting the speed of 3D printing and studied the relationship between thermal property and printing speed.Our microstructure study demonstrates that highly porous structures appear at higher speeds,and there is a nearly linear relationship between porosity and printing speed.The thermal conductivity of samples fabricated by different printing speeds is characterized.Then,the correlation between porosity,thermal conductivity,and scanning speed is established.Based on this correlation,the thermal conductivity of a sample can be predicted from its printing speed.We fabricated a new sample at a different speed,and the thermal conductivity measurement agrees well with the value predicted from the correlation.To explore thermal transport physics,the effects of pore structure and temperature on the thermal performance of the printed block are also studied.Our work demonstrates that the combination of the 3D printing technique and the printing speed control can regulate the thermophysical properties of materials.展开更多
As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) Modulation.It...As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) Modulation.It can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation scheme.How to design a feasible constellation is the most concerned problem of PQAM currently.This paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation scheme.Secondly,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for PQAM.Finally,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.展开更多
Poly(3-hexylthiophene)(P3HT)is one of the most promising hole-transporting materials in the pursuit of efficient and stable perovskite solar cells due to its outstanding stability and low cost.However,the intrinsic lo...Poly(3-hexylthiophene)(P3HT)is one of the most promising hole-transporting materials in the pursuit of efficient and stable perovskite solar cells due to its outstanding stability and low cost.However,the intrinsic low carrier density of P3 HT and poor contact between the P3HT/perovskite interface always lead to a low performance of the solar cell,while conventional chemical doping always makes the films unstable and limits the scalability.In this work,for the first time,we simultaneously enhanced the hole transporting properties of P3HT film and the interface of perovskite by doping it with a judiciously designed oxidized small molecule organic semiconductor.The organic salt not only can promote the lamellar crystallinity of P3HT to obtain better charge transport properties,but also reduce the defects of perovskite.As a result,we achieved champion efficiencies of 23.0%for small-area solar cells and 18.8%for larger-area modules(48.0 cm^(2)).This efficiency is the highest value for P3HT-based perovskite modules.Moreover,the solar cells show excellent operational stability,retaining over 95%of their initial efficiencies after1200 h of continuous operation.展开更多
It is necessary to investigate the characteristics of Mesenchymal stem cells(MSCs)derived exosomes,and especially their application in tissue regeneration.Previous studies have shown that inflammatory stimulation enha...It is necessary to investigate the characteristics of Mesenchymal stem cells(MSCs)derived exosomes,and especially their application in tissue regeneration.Previous studies have shown that inflammatory stimulation enhanced the secretion of MSC-derived exosomes with stronger anti-inflammatory protein,cytokine profiles,and functional RNA via altering COX2/PGE2 pathway.Recently,accumulating evidence has also revealed that biophysical cues(especially biomechanical cues)in cell microenvironment have significant effects not only on cells but also on their exosomes.It has been reported that applying bi-axial strain to MSCs induces formation of a stiffer cytoskeleton through mTORC2 signaling,which biases against adipogenic differentiation and toward osteoblastogenesis.At the same time,For example,dimensionality,composition and stiffness of the extracellular matrix(ECM)has been proved to affect the size and composition of exosomes secreted by cancer cells.However,the effects of biomechanical cues in the three-dimensional(3D)microenvironment on stem cell-derived exosomes remains to be unveiled.Therefore,it is important to understand the roles of 3D cell mechanical microenvironment in regulating the characteristics of stem cell-derived exosomes and develop more efficient approaches to enhance their functions.This study aimed to explore the changes in characteristics of exosomes secreted by MSCs in periodontium in response to the matrix strain in 3D.Periodontal ligament stem cells(PDLSCs)were cultured in a 3D strain microenvironment engineered with microscale magnetically stretched collagen hydrogels.The morphology,particle distribution,marker protein expression of PDLSC-derived exosomes were analyzed.Then the pro-osteogenic property of exosomes was evaluated by assessing cell viability,proliferation,migration and osteogenic differentiation of target cells,for instance human bone marrow mesenchymal stem cells(hBMSCs).Detailed characterizations revealed that PDLSC-derived exosomes in the 3D strain mi-croenvironment were with similar morphology,particle distribution and surface markers.Notably,Exosomes secreted by PDLSCs in strain microenvironment were more endocytosed by hBMSCs and were more potent in improving proliferation and migration of hBMSCs,comparing with PDLSCs in non-strain environment.Alizarin red staining and molecular biology experiments confirmed that treatment of exosomes secreted by PDLSCs under mechanical stimulation led to a significant increase in osteogenic differentiation of hBMSCs in vitro.Meanwhile,in vivo study also indicated that PDLSC-derived exosomes obtained from the 3D strain microenvironment could obviously promote new bone formation.Our findings revealed that mechanical cues profoundly affected the characteristics of PDLSC-derived exosomes,especially for their bio-activity,providing a foundation for using the 3D mechanical microenvironment to enhance the osteo-inductive functions of stem cell-derived exosomes in cell-free therapy for bone regeneration.展开更多
Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanopart...Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.展开更多
The influences of two kinds of casting modules of metal casting （MC） and expandable pattern casting （EPC） on the corrosion behavior of Mg-11Gd-3Y alloy were studied by electrochemical measurements, scanning electr...The influences of two kinds of casting modules of metal casting （MC） and expandable pattern casting （EPC） on the corrosion behavior of Mg-11Gd-3Y alloy were studied by electrochemical measurements, scanning electron microscopy （SEM） observation, X-ray diffractometry （XRD） and X-ray photoelectron spectroscopy （XPS） analysis. It is found that the quantity of the Mg 24 （Gd, Y） 5 phase in MC is more than that in EPC due to the cooling rate. There is more alloying element dissolved in the matrix compared with MC. For EPC, the galvanic corrosion effect between the matrix and the Mg 24 （Gd, Y） 5 phase decreases and the corrosion resistance increases compared with the MC. The chief corrosion mode for Mg-11Gd-3Y alloy is pitting corrosion because most of the alloying elements are transformed into intermetallic phases. The average corrosion rate of the MC alloy in the immersion test is five times higher than that of EPC alloy and yttrium is present in the product film, which will provide increased protection for Mg-11Gd-3Y alloy. The electrochemical measurements and immersion test show that the EPC process increases the corrosion resistance compared with the MC Mg-11Gd-3Y alloy.展开更多
A simple and fast route for the synthesis of metal-organic framework（MOF） particles was presented.Cu 3（BTC） 2（HKUST-1,BTC=1,3,5-benzenetricarboxylate）,one of the most well-known MOFs,was synthesized at room temp...A simple and fast route for the synthesis of metal-organic framework（MOF） particles was presented.Cu 3（BTC） 2（HKUST-1,BTC=1,3,5-benzenetricarboxylate）,one of the most well-known MOFs,was synthesized at room temperature via coordination modulation method.By adding different modulators（monocarboxylic acids） into the reaction system,the morphologies of HKUST-1 crystals were tuned from nano spheres to micro octahedrons at room temperature without any complex equipment.X-Ray diffractions and gas sorption measurements revealed highly crystalline particles with large Brunauer-Emmett-Teller（BET） surface areas（1116―1273 m^ 2 /g） and total pore volumes（0.62―0.73 cm^ 3 /g）.The significantly small particle sizes and high capacity of gas sorption are considered advantageous for envisaged application in practical industrial process.展开更多
Semiconducting piezoelectricα-In_(2)Se_(3) and 3R MoS_(2) have attracted tremendous attention due to their unique electronic properties.Artificial van der Waals(vdWs)hetero-structures constructed withα-In_(2)Se_(3)a...Semiconducting piezoelectricα-In_(2)Se_(3) and 3R MoS_(2) have attracted tremendous attention due to their unique electronic properties.Artificial van der Waals(vdWs)hetero-structures constructed withα-In_(2)Se_(3)and 3R MoS_(2)flakes have shown promising applications in optoelectronics and photocatal-ysis.Here,we present the first flexibleα-In_(2)Se_(3)/3R MoS_(2)vdWs p-n heterojunction devices for photodetection from the visible to near infrared region.These heterojunction devices exhibit an ultrahigh photoresponsivity of 2.9×10^(3)A W^(−1) and a substantial specific detectivity of 6.2×10^(10) Jones under a compressive strain of−0.26%.The photocurrent can be increased by 64%under a tensile strain of+0.35%,due to the heterojunction energy band modulation by piezoelectric polarization charges at the hetero-junction interface.This work demonstrates a feasible approach to enhancement of α-In_(2)Se_(3)/3R MoS_(2) photoelectric response through an appropriate mechanical stimulus.展开更多
Due to the negative roles of tumor microenvironment(TME)in compromising therapeutic responses of various cancer therapies,it is expected that modulation of TME may be able to enhance the therapeutic responses during c...Due to the negative roles of tumor microenvironment(TME)in compromising therapeutic responses of various cancer therapies,it is expected that modulation of TME may be able to enhance the therapeutic responses during cancer treatment.Herein,we develop a concise strategy to prepare pH-responsive nanoparticles via the CaCO3-assisted double emulsion method,thereby enabling effective co-encapsulation of both doxorubicin(DOX),an immunogenic cell death(ICD)inducer,and alkylated NLG919(aNLG919),an inhibitor of indoleamine 2,3-dioxygenase 1(IDO1).The obtained DOX/aNLG919-loaded CaCO3 nanoparticles(DNCaNPs)are able to cause effective ICD of cancer cells and at the same time restrict the production of immunosuppressive kynurenine by inhibiting IDO1.Upon intravenous injection,such DNCaNPs show efficient tumor accumulation,improved tumor penetration of therapeutics and neutralization of acidic TME.As a result,those DNCaNPs can elicit effective anti-tumor immune responses featured in increased density of tumor-infiltrating CD8+cytotoxic T cells as well as depletion of immunosuppressive regulatory T cells(Tregs),thus effectively suppressing the growth of subcutaneous CT26 and orthotopic 4T1 tumors on the Balb/c mice through combined chemotherapy&immunotherapy.This study presents a compendious strategy for construction of pH-responsive nanoparticles,endowing significantly enhanced chemo-immunotherapy of cancer by overcoming the immunosuppressive TME.展开更多
We report three-dimensional fluorescence emission difference(3D-FED)microscopy using a spatial light modulator(SLM).Zero phase,0–2vortex phase and binary 0-pi phase are loaded on the SLM to generate the correspondin...We report three-dimensional fluorescence emission difference(3D-FED)microscopy using a spatial light modulator(SLM).Zero phase,0–2vortex phase and binary 0-pi phase are loaded on the SLM to generate the corresponding solid,doughnut and z-axis hollow excitation spot,respectively.Our technique achieves super-resolved image by subtracting three di®erently acquired images with proper subtractive factors.Detailed theoretical analysis and simulation tests are proceeded to testify the performance of 3D-FED.Also,the improvement of lateral and axial resolution is demonstrated by imaging 100 nm°uorescent beads.The experiment yields lateral resolution of 140 nm and axial resolution of approximate 380 nm.展开更多
Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulatio...Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulation plays an important role in the developmental origins of osteoporosis; however, few studies have investigated the potential of epigenetic therapy to improve or rescue the osteogenic ability of bone marrow mesenchymal stem cells(BMMSCs) under osteoporotic conditions. Here, we investigated pargyline, an inhibitor of lysine-specific demethylase 1(LSD1), which mainly catalyzes the demethylation of the di- and mono-methylation of H3K4. We demonstrated that 1.5 mmol·Lpargyline was the optimal concentration for the osteogenic differentiation of human BMMSCs. Pargyline rescued the osteogenic differentiation ability of mouse BMMSCs under osteoporotic conditions by enhancing the dimethylation level of H3K4 at the promoter regions of osteogenesis-related genes. Moreover, pargyline partially rescued or prevented the osteoporotic conditions in aged or ovariectomized mouse models, respectively. By introducing the concept of epigenetic therapy into the field of osteoporosis, this study demonstrated that LSD1 inhibitors could improve the clinical practice of MSC-based bone tissue engineering and proposes their novel use to treat osteoporosis.展开更多
Many studies point to an association between Helicobacter pylori(H.pylori)infection and inflammatory bowel diseases(IBD).Although controversial,this association indicates that the presence of the bacterium somehow aff...Many studies point to an association between Helicobacter pylori(H.pylori)infection and inflammatory bowel diseases(IBD).Although controversial,this association indicates that the presence of the bacterium somehow affects the course of IBD.It appears that H.pylori infection influences IBD through changes in the diversity of the gut microbiota,and hence in local chemical characteristics,and alteration in the pattern of gut immune response.The gut immune response appears to be modulated by H.pylori infection towards a less aggressive inflammatory response and the establishment of a targeted response to tissue repair.Therefore,a T helper 2(Th2)/macrophage M2 response is stimulated,while the Th1/macrophage M1 response is suppressed.The immunomodulation appears to be associated with intrinsic factors of the bacteria,such as virulence factors-such oncogenic protein cytotoxin-associated antigen A,proteins such H.pylori neutrophil-activating protein,but also with microenvironmental changes that favor permanence of H.pylori in the stomach.These changes include the increase of gastric mucosal pH by urease activity,and suppression of the stomach immune response promoted by evasion mechanisms of the bacterium.Furthermore,there is a causal relationship between H.pylori infection and components of the innate immunity such as the NLR family pyrin domain containing 3 inflammasome that directs IBD toward a better prognosis.展开更多
基金supported by the National Natural Science Foundation of China(52273264)the Outstanding Youth Fund of Heilongjiang Province(JQ 2020B002).
文摘Electronic-state modulation strategy offers great potential in designing RuO_(2)-based bifunctionalelectrocatalysts for rechargeable Zn-air batteries(ZABs).Various three-dimensional(3D)transition metal oxides are attempted to couple with RuO_(2)for constructing an appropriate Ru—O—M interface.This work aims to construct Co_(3)O_(4)-RuO_(2)heterostructures on carbon sheets(Co_(3)O_(4)/RuO_(2)/NCNS)for boosting electronic transfer and regulation.Experiments and theoretical calculations identify the electronic transfer from Co_(3)O_(4)to RuO_(2)that modulates the electronic structure of metal surfaces/interfaces.Specifically,it leads to the increase in Co3+content,electron-rich state at RuO_(2)surface and electronic accumulation at interfaces.Moreover,this electronic-state modulation optimizes the d-band center in Co_(3)O_(4)/RuO_(2)that lowers the reaction barriers and endows interfaces as the biggest contributor to oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)performance,The Co_(3)O_(4)/RuO_(2)/NCNS shows a quite low potential difference of 0.62 V and remarkable durability for ORR/OER.Co_(3)O_(4)/RuO_(2)/NCNS-assembled ZABs exhibit an excellent specific capacity of 818.3 mA h g^(-1)and a superior lifespan over 750 h.
基金supported by the National Key R&D Program of China(Nos.2018YFB1106100,2019YFE0119900)the National Natural Science Foundation of China(No.52076156)the Fundamental Research Funds for the Central Universities(No.2042020kf0194)。
文摘It is desirable to fabricate materials with adjustable physical properties that can be used in different industrial applications.Since the property of a material is highly dependent on its inner structure,the understanding of structure–property correlation is critical to the design of engineering materials.3D printing appears as a mature method to effectively produce micro-structured materials.In this work,we created different stainless-steel microstructures by adjusting the speed of 3D printing and studied the relationship between thermal property and printing speed.Our microstructure study demonstrates that highly porous structures appear at higher speeds,and there is a nearly linear relationship between porosity and printing speed.The thermal conductivity of samples fabricated by different printing speeds is characterized.Then,the correlation between porosity,thermal conductivity,and scanning speed is established.Based on this correlation,the thermal conductivity of a sample can be predicted from its printing speed.We fabricated a new sample at a different speed,and the thermal conductivity measurement agrees well with the value predicted from the correlation.To explore thermal transport physics,the effects of pore structure and temperature on the thermal performance of the printed block are also studied.Our work demonstrates that the combination of the 3D printing technique and the printing speed control can regulate the thermophysical properties of materials.
基金supported in part by the National Natural Science Foundation of China (61561039, 61271177, and 61461044)
文摘As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) Modulation.It can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation scheme.How to design a feasible constellation is the most concerned problem of PQAM currently.This paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation scheme.Secondly,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for PQAM.Finally,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.
基金financially supported by the National Natural Science Foundation of China(52472248 and 22075221)the Key Research and Development Project of Shanxi Province(202202060301003 and 202202060301015)the Innovation Program of Wuhan-Shuguang Project(2023010201020367)。
文摘Poly(3-hexylthiophene)(P3HT)is one of the most promising hole-transporting materials in the pursuit of efficient and stable perovskite solar cells due to its outstanding stability and low cost.However,the intrinsic low carrier density of P3 HT and poor contact between the P3HT/perovskite interface always lead to a low performance of the solar cell,while conventional chemical doping always makes the films unstable and limits the scalability.In this work,for the first time,we simultaneously enhanced the hole transporting properties of P3HT film and the interface of perovskite by doping it with a judiciously designed oxidized small molecule organic semiconductor.The organic salt not only can promote the lamellar crystallinity of P3HT to obtain better charge transport properties,but also reduce the defects of perovskite.As a result,we achieved champion efficiencies of 23.0%for small-area solar cells and 18.8%for larger-area modules(48.0 cm^(2)).This efficiency is the highest value for P3HT-based perovskite modules.Moreover,the solar cells show excellent operational stability,retaining over 95%of their initial efficiencies after1200 h of continuous operation.
基金financially supported by the Young Elite Scientist Sponsorship Program by CAST ( 2018QNRC001)the China Postdoctoral Science Foundation ( 2018M631172)
文摘It is necessary to investigate the characteristics of Mesenchymal stem cells(MSCs)derived exosomes,and especially their application in tissue regeneration.Previous studies have shown that inflammatory stimulation enhanced the secretion of MSC-derived exosomes with stronger anti-inflammatory protein,cytokine profiles,and functional RNA via altering COX2/PGE2 pathway.Recently,accumulating evidence has also revealed that biophysical cues(especially biomechanical cues)in cell microenvironment have significant effects not only on cells but also on their exosomes.It has been reported that applying bi-axial strain to MSCs induces formation of a stiffer cytoskeleton through mTORC2 signaling,which biases against adipogenic differentiation and toward osteoblastogenesis.At the same time,For example,dimensionality,composition and stiffness of the extracellular matrix(ECM)has been proved to affect the size and composition of exosomes secreted by cancer cells.However,the effects of biomechanical cues in the three-dimensional(3D)microenvironment on stem cell-derived exosomes remains to be unveiled.Therefore,it is important to understand the roles of 3D cell mechanical microenvironment in regulating the characteristics of stem cell-derived exosomes and develop more efficient approaches to enhance their functions.This study aimed to explore the changes in characteristics of exosomes secreted by MSCs in periodontium in response to the matrix strain in 3D.Periodontal ligament stem cells(PDLSCs)were cultured in a 3D strain microenvironment engineered with microscale magnetically stretched collagen hydrogels.The morphology,particle distribution,marker protein expression of PDLSC-derived exosomes were analyzed.Then the pro-osteogenic property of exosomes was evaluated by assessing cell viability,proliferation,migration and osteogenic differentiation of target cells,for instance human bone marrow mesenchymal stem cells(hBMSCs).Detailed characterizations revealed that PDLSC-derived exosomes in the 3D strain mi-croenvironment were with similar morphology,particle distribution and surface markers.Notably,Exosomes secreted by PDLSCs in strain microenvironment were more endocytosed by hBMSCs and were more potent in improving proliferation and migration of hBMSCs,comparing with PDLSCs in non-strain environment.Alizarin red staining and molecular biology experiments confirmed that treatment of exosomes secreted by PDLSCs under mechanical stimulation led to a significant increase in osteogenic differentiation of hBMSCs in vitro.Meanwhile,in vivo study also indicated that PDLSC-derived exosomes obtained from the 3D strain microenvironment could obviously promote new bone formation.Our findings revealed that mechanical cues profoundly affected the characteristics of PDLSC-derived exosomes,especially for their bio-activity,providing a foundation for using the 3D mechanical microenvironment to enhance the osteo-inductive functions of stem cell-derived exosomes in cell-free therapy for bone regeneration.
基金support from the Chinese Scholarship Council(201706220080)for W.H.the Natural Science Foundation of Hunan Province(2019JJ50526)for C.P.+1 种基金The Danish Council for Independent Research for the YDUN project(DFF 4093-00297)to J.Z.Villum Experiment(grant No.35844)for X.X.
文摘Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.
基金Project(2007CB613705)supported by the National Basic Research Program of China
文摘The influences of two kinds of casting modules of metal casting （MC） and expandable pattern casting （EPC） on the corrosion behavior of Mg-11Gd-3Y alloy were studied by electrochemical measurements, scanning electron microscopy （SEM） observation, X-ray diffractometry （XRD） and X-ray photoelectron spectroscopy （XPS） analysis. It is found that the quantity of the Mg 24 （Gd, Y） 5 phase in MC is more than that in EPC due to the cooling rate. There is more alloying element dissolved in the matrix compared with MC. For EPC, the galvanic corrosion effect between the matrix and the Mg 24 （Gd, Y） 5 phase decreases and the corrosion resistance increases compared with the MC. The chief corrosion mode for Mg-11Gd-3Y alloy is pitting corrosion because most of the alloying elements are transformed into intermetallic phases. The average corrosion rate of the MC alloy in the immersion test is five times higher than that of EPC alloy and yttrium is present in the product film, which will provide increased protection for Mg-11Gd-3Y alloy. The electrochemical measurements and immersion test show that the EPC process increases the corrosion resistance compared with the MC Mg-11Gd-3Y alloy.
基金Supported by the National Natural Science Foundation of China(Nos.21173034,20907006)
文摘A simple and fast route for the synthesis of metal-organic framework（MOF） particles was presented.Cu 3（BTC） 2（HKUST-1,BTC=1,3,5-benzenetricarboxylate）,one of the most well-known MOFs,was synthesized at room temperature via coordination modulation method.By adding different modulators（monocarboxylic acids） into the reaction system,the morphologies of HKUST-1 crystals were tuned from nano spheres to micro octahedrons at room temperature without any complex equipment.X-Ray diffractions and gas sorption measurements revealed highly crystalline particles with large Brunauer-Emmett-Teller（BET） surface areas（1116―1273 m^ 2 /g） and total pore volumes（0.62―0.73 cm^ 3 /g）.The significantly small particle sizes and high capacity of gas sorption are considered advantageous for envisaged application in practical industrial process.
基金MOE AcRF Tier2(2018-T2-2-005),MOE AcRF Tier1(2018-T1-005-001)A^(*)STAR AME IRG Grant SERC A1983c0027,Singapore.
文摘Semiconducting piezoelectricα-In_(2)Se_(3) and 3R MoS_(2) have attracted tremendous attention due to their unique electronic properties.Artificial van der Waals(vdWs)hetero-structures constructed withα-In_(2)Se_(3)and 3R MoS_(2)flakes have shown promising applications in optoelectronics and photocatal-ysis.Here,we present the first flexibleα-In_(2)Se_(3)/3R MoS_(2)vdWs p-n heterojunction devices for photodetection from the visible to near infrared region.These heterojunction devices exhibit an ultrahigh photoresponsivity of 2.9×10^(3)A W^(−1) and a substantial specific detectivity of 6.2×10^(10) Jones under a compressive strain of−0.26%.The photocurrent can be increased by 64%under a tensile strain of+0.35%,due to the heterojunction energy band modulation by piezoelectric polarization charges at the hetero-junction interface.This work demonstrates a feasible approach to enhancement of α-In_(2)Se_(3)/3R MoS_(2) photoelectric response through an appropriate mechanical stimulus.
基金partially supported by the National Natural Science Foundation of China(51802209,22077093,51761145041,51525203)the National Research Programs from Ministry of Science and Technology(MOST)of China(2016YFA0201200)+3 种基金the Natural Science Foundation of Jiangsu Province(BK20180848)the Jiangsu Social Development Project(BE2019658)Collaborative Innovation Center of Suzhou Nano Science and Technologythe 111 Program from the Ministry of Education of China.
文摘Due to the negative roles of tumor microenvironment(TME)in compromising therapeutic responses of various cancer therapies,it is expected that modulation of TME may be able to enhance the therapeutic responses during cancer treatment.Herein,we develop a concise strategy to prepare pH-responsive nanoparticles via the CaCO3-assisted double emulsion method,thereby enabling effective co-encapsulation of both doxorubicin(DOX),an immunogenic cell death(ICD)inducer,and alkylated NLG919(aNLG919),an inhibitor of indoleamine 2,3-dioxygenase 1(IDO1).The obtained DOX/aNLG919-loaded CaCO3 nanoparticles(DNCaNPs)are able to cause effective ICD of cancer cells and at the same time restrict the production of immunosuppressive kynurenine by inhibiting IDO1.Upon intravenous injection,such DNCaNPs show efficient tumor accumulation,improved tumor penetration of therapeutics and neutralization of acidic TME.As a result,those DNCaNPs can elicit effective anti-tumor immune responses featured in increased density of tumor-infiltrating CD8+cytotoxic T cells as well as depletion of immunosuppressive regulatory T cells(Tregs),thus effectively suppressing the growth of subcutaneous CT26 and orthotopic 4T1 tumors on the Balb/c mice through combined chemotherapy&immunotherapy.This study presents a compendious strategy for construction of pH-responsive nanoparticles,endowing significantly enhanced chemo-immunotherapy of cancer by overcoming the immunosuppressive TME.
基金This work was financially supported by grants from the National Basic Research Program of China (973 Program)(No.2015CB352003)the National Natural Science Foundation of China (Nos.61377013,61335003,61378051,and 61427818)+1 种基金NSFC of Zhejiang province LR16F050001,Innovation Joint Research Center for iCPS (2015XZZX005-01)Open Foundation of the State Key Laboratory of Modern Optical Instrumentation.
文摘We report three-dimensional fluorescence emission difference(3D-FED)microscopy using a spatial light modulator(SLM).Zero phase,0–2vortex phase and binary 0-pi phase are loaded on the SLM to generate the corresponding solid,doughnut and z-axis hollow excitation spot,respectively.Our technique achieves super-resolved image by subtracting three di®erently acquired images with proper subtractive factors.Detailed theoretical analysis and simulation tests are proceeded to testify the performance of 3D-FED.Also,the improvement of lateral and axial resolution is demonstrated by imaging 100 nm°uorescent beads.The experiment yields lateral resolution of 140 nm and axial resolution of approximate 380 nm.
基金supported by grants from the National Natural Science Foundation of China(81200763 to WG and 81070809 to YZ)the Program for New Century Excellent Talents(NCET)at the University from Ministry of Education of China(NCET-11-0026)+1 种基金the PKU School of Stomatology for Talented Young Investigators(PKUSS20150107)the Construction Program for the National Key Clinical Specialty from the National Health and Family Planning Commission of China(2011)
文摘Bone tissue engineering may be hindered by underlying osteoporosis because of a decreased osteogenic ability of autologous seed cells and an unfavorably changed microenvironment in these patients. Epigenetic regulation plays an important role in the developmental origins of osteoporosis; however, few studies have investigated the potential of epigenetic therapy to improve or rescue the osteogenic ability of bone marrow mesenchymal stem cells(BMMSCs) under osteoporotic conditions. Here, we investigated pargyline, an inhibitor of lysine-specific demethylase 1(LSD1), which mainly catalyzes the demethylation of the di- and mono-methylation of H3K4. We demonstrated that 1.5 mmol·Lpargyline was the optimal concentration for the osteogenic differentiation of human BMMSCs. Pargyline rescued the osteogenic differentiation ability of mouse BMMSCs under osteoporotic conditions by enhancing the dimethylation level of H3K4 at the promoter regions of osteogenesis-related genes. Moreover, pargyline partially rescued or prevented the osteoporotic conditions in aged or ovariectomized mouse models, respectively. By introducing the concept of epigenetic therapy into the field of osteoporosis, this study demonstrated that LSD1 inhibitors could improve the clinical practice of MSC-based bone tissue engineering and proposes their novel use to treat osteoporosis.
文摘Many studies point to an association between Helicobacter pylori(H.pylori)infection and inflammatory bowel diseases(IBD).Although controversial,this association indicates that the presence of the bacterium somehow affects the course of IBD.It appears that H.pylori infection influences IBD through changes in the diversity of the gut microbiota,and hence in local chemical characteristics,and alteration in the pattern of gut immune response.The gut immune response appears to be modulated by H.pylori infection towards a less aggressive inflammatory response and the establishment of a targeted response to tissue repair.Therefore,a T helper 2(Th2)/macrophage M2 response is stimulated,while the Th1/macrophage M1 response is suppressed.The immunomodulation appears to be associated with intrinsic factors of the bacteria,such as virulence factors-such oncogenic protein cytotoxin-associated antigen A,proteins such H.pylori neutrophil-activating protein,but also with microenvironmental changes that favor permanence of H.pylori in the stomach.These changes include the increase of gastric mucosal pH by urease activity,and suppression of the stomach immune response promoted by evasion mechanisms of the bacterium.Furthermore,there is a causal relationship between H.pylori infection and components of the innate immunity such as the NLR family pyrin domain containing 3 inflammasome that directs IBD toward a better prognosis.
