Objective To explore the relationship between serum chloride levels and prognosis in patients with hepatic coma in the intensive care unit(ICU).Methods We analyzed 545 patients with hepatic coma in the ICU from the Me...Objective To explore the relationship between serum chloride levels and prognosis in patients with hepatic coma in the intensive care unit(ICU).Methods We analyzed 545 patients with hepatic coma in the ICU from the Medical Information Mart for Intensive Care IV(MIMIC-IV)database.Associations between serum chloride levels and 28-day and 1-year mortality rates were assessed using restricted cubic splines(RCSs),Kaplan-Meier(KM)curves,and Cox regression.Subgroup analyses,external validation,and mechanistic studies were also performed.Results A total of 545 patients were included in the study.RCS analysis revealed a U-shaped association between serum chloride levels and mortality in patients with hepatic coma.The KM curves indicated lower survival rates among patients with low chloride levels(<103 mmol/L).Low chloride levels were independently linked to increased 28-day and 1-year all-cause mortality rates.In the multivariate models,the hazard ratio(HR)for 28-day mortality in the low-chloride group was 1.424(95%confidence interval[CI]:1.041–1.949),while the adjusted hazard ratio for 1-year mortality was 1.313(95%CI:1.026–1.679).Subgroup analyses and external validation supported these findings.Cytological experiments suggested that low chloride levels may activate the phosphorylation of the NF-κB signaling pathway,promote the expression of pro-inflammatory cytokines,and reduce neuronal cell viability.Conclusion Low serum chloride levels are independently associated with increased mortality in patients with hepatic coma.展开更多
In this study,dynamic selenonium salts were incorporated into a polyurethane(PU)matrix to develop transparent,healable and antibacterial coatings.Through systematic formulation optimization,optically clear materials w...In this study,dynamic selenonium salts were incorporated into a polyurethane(PU)matrix to develop transparent,healable and antibacterial coatings.Through systematic formulation optimization,optically clear materials with excellent room-temperature hardness were obtained.Fine-tuning the selenonium content established a synergy between antibacterial performance and network dynamics,as evidenced by vitrimer-like rheological behavior at elevated temperatures.Consequently,the coatings exhibited outstanding reprocessability while maintaining high transparency and structural stability after prolonged saltwater exposure.These integrated features underscore the potential of the developed cationic PU coatings as robust,multifunctional materials for electronic device protection and marine antifouling,combining long-term transparency,recyclability,and antibacterial durability.展开更多
CdZnS solid solutions with strong light absorption are promising materials for solar-driven COreduction;however,their relatively weak redox ability and intrinsic photo-corrosion limit their further development as a ph...CdZnS solid solutions with strong light absorption are promising materials for solar-driven COreduction;however,their relatively weak redox ability and intrinsic photo-corrosion limit their further development as a photocatalyst.The addition of a second photocatalyst with a suitable band structure to construct a S-scheme photocatalytic system can solve both problems simultaneously.Here,we report a S-scheme photocatalyst based on the heterostructure of CoTiO_(3)/CdZnS(abbreviated as CoTiO_(3)/Cd_(9.51)Zn_(0.49)S_(10))that enables the efficient photocatalytic reduction of CO.Detailed physicochemical characterization resolves the S-scheme charge transfer mechanism in this composite photocatalyst.With the well-designed structure of particles and desirable band offsets,this hybrid system offers visible light absorption in a broad spectral region,large surface area,strong redox ability,and fast carrier separation and transportation.Under visible-light illumination,the CoTiO_(3)/Cd Zn S hybrid system displays a CO formation rate of about 11 mmol hgcombined with a long-term operational stability.Besides,a high apparent quantum efficiency(AQE)of 7.27%is realized for the CO_(2)-to-CO reduction reaction by the optimized Co TiO/Cd Zn S hybrid under 420 nm monochromatic light irradiation.展开更多
Metal halide perovskite(MHP)quantum dots(QDs)offer immense potentialfor several areas of photonics research due to their easy and low-costfabrication and excellent optoelectronic properties.However,practicalapplicatio...Metal halide perovskite(MHP)quantum dots(QDs)offer immense potentialfor several areas of photonics research due to their easy and low-costfabrication and excellent optoelectronic properties.However,practicalapplications of MHP QDs are limited by their poor stability and,in particular,their tendency to aggregate.Here,we develop a two-step double-solventstrategy to grow and confine CsPbBr_(3)QDs within the three-dimensional(3D)cavities of a mesoporous SBA-16 silica scaffold(CsPbBr_(3)@SBA-16).Strongconfinement and separation of the MHP QDs lead to a relatively uniform sizedistribution,narrow luminescence,and good ambient stability over 2 months.In addition,the CsPbBr_(3)@SBA-16 presents a high activity and stability forvisible-light-driven photocatalytic toluene C(sp^(3))-H bond activation toproduce benzaldehyde with~730 umolg^(-1)h^(-l) yield rate and near-unityselectivity.Similarly,the structural stability of CsPbBr_(3)@SBA-16QDs issuperior to that of both pure CsPbBr3 QDs and those confined in MCM-41with 1D channels.展开更多
Gold(Au)nanostructures(NSs)have been widely employed as cocatalysts to improve the photoactivity of semiconductor materials,while a systematic summary of the engineering approaches of Au NSs to maximize the solar-to-f...Gold(Au)nanostructures(NSs)have been widely employed as cocatalysts to improve the photoactivity of semiconductor materials,while a systematic summary of the engineering approaches of Au NSs to maximize the solar-to-fuel conversion efficiency is still lacking.In this review,the recently developed strategies for elevating the overall photocatalytic performance of Au-based catalysts and the deep physical chemistry mechanisms are highlighted.Firstly,the synthetic approaches of Au NSs are summarized,followed by an elaboration on their multiple functions in improving photoactivity.Afterward,modification strategies of Au NSs used to enhance the photocatalytic efficiency of Au-semiconductor composites,including controlling the Au NSs morphology,size,crystal phase,defect engineering,alloying with different metals,modulating interfacial interaction,and introducing an external field,are summarized and discussed independently.Additionally,advanced characterization techniques that can provide insights into the charge dynamics of the photocatalysts are introduced.Finally,we share our opinion on the challenges and outline potentially promising opportunities and directions for efficient Au-based photocatalysis research moving forward.We sincerely look forward to this review can deliver insightful views to design efficient Au-based photocatalysts and spur certain innovations to other metal-based catalysts.展开更多
A promising strategy to support broiler health and performance in a sustainable way is the enhancement of microbial fibre fermentation in broilers.This fermentation mainly occurs in the caeca,but the actual particle s...A promising strategy to support broiler health and performance in a sustainable way is the enhancement of microbial fibre fermentation in broilers.This fermentation mainly occurs in the caeca,but the actual particle size range that allows caecal influx has not yet been described.This study aimed to understand the physical limitations of caecal influx as a function of broiler age by using both solid and soluble markers.In the first trial,the caecal filter mechanism was studied by microscopically visualising the caecal entrance and measuring caecal lobe development and digesta particle size as a function of age(d 8-36)for 44 broilers(Ross 308)receiving a conventional wheat-based diet.In two consecutive trials,microcrystalline cellulose beads(100-700 mm)and a combination of fluorescent polystyrene beads(5-30 mm)and chromium-ethylenediamine tetraacetic acid(Cr-EDTA)were administered to 176 and 189 broilers,respectively,at different ages(d 8-36).Results showed that the actual caecal entrance diameter is significantly reduced due to a dense villi network acting as a filter for digesta inflow.This explains the size gap between the average digesta particle size(D50)of the ileum(451-322 mm)and caeca(5-19 mm),and the outer diameter of the caecal entrance(2000-4000 mm)on d 8 to 36.In contrast to the caecal D50,cellulose beads of 700 mm already entered the caeca at 8 d of age,even though the general caecal influx of digesta particles larger than 100 mm seemed very limited.The caecal influx of the markers further exhibited large individual variation among birds.A maximum of 13.2%(d 9)and 4.3%(d 29)of the total administered soluble marker(Cr-EDTA)was detected in the caeca,5 h after bolus administration.Both solid and soluble markers showed a larger concentration in the caeca at a young age compared to older ages(P<0.01),possibly related to the limited caecal functioning early in life.These findings highlight the importance of carefully selecting the physical properties of fibres to be added as a function of age to further improve caecal fibre fermentation in broilers.展开更多
Ultrasmall gold(Au)clusters have been regarded as one of the prototypes materials for solar energy conversion due to their unique strong molecular-like light absorption properties.However,the light-induced aggregation...Ultrasmall gold(Au)clusters have been regarded as one of the prototypes materials for solar energy conversion due to their unique strong molecular-like light absorption properties.However,the light-induced aggregation of Au clusters into nanoparticles is one of the most important factors that restricts its application in photocatalysis.Although Au clusters aggregation has been widely demonstrated,the underlying mechanism for cluster fusion is still unclear due to the lack of experimental evidence.Herein,we report the direct observation of Au clusters on TiO_(2) nanosheets aggregating when used as visible light photocatalysts for the reduction of nitroaromatics.Through in situ high-resolution transmission electron microscopy(TEM),the coexistence of two fusion mechanisms of Au clusters on TiO_(2) under ultraviolet-visible(UV-Vis)light irradiation in air is identified,i.e.,the migration and coalescence(MC)and Ostwald ripening(OR).Additionally,the correlation between the photostability of Au clusters and reaction atmospheres has been investigated,among which Au clusters have higher stability in an inert N_(2) atmosphere or vacuum than the oxidizing atmospheres(i.e.,air and O_(2)).These results indicate the inherent stability of Au cluster during photocatalysis,and instability comes from the consuming of ligand layer.This work not only discloses the underlying mechanism of Au cluster sintering but also provides guidelines for enhancing metal clusters-based photocatalysts stability.展开更多
The distribution of photo-crosslinkable moieties onto a protein backbone can affect a biomaterial’s crosslinking behavior, and therefore also its mechanical and biological properties. A profound insight in this respe...The distribution of photo-crosslinkable moieties onto a protein backbone can affect a biomaterial’s crosslinking behavior, and therefore also its mechanical and biological properties. A profound insight in this respect is essential for biomaterials exploited in tissue engineering and regenerative medicine. In the present work, photo-crosslinkable moieties have been introduced on the primary amine groups of: (i) a recombinant collagen peptide (RCPhC1) with a known amino acid (AA) sequence, and (ii) bovine skin collagen (COL BS) with an unknown AA sequence. The degree of substitution (DS) was quantified with two conventional techniques: an ortho-phthalic dialdehyde (OPA) assay and ^(1)H NMR spectroscopy. However, neither of both provides information on the exact type and location of the modified AAs. Therefore, for the first time, proteomic analysis was evaluated herein as a tool to identify functionalized AAs as well as the exact position of photo-crosslinkable moieties along the AA sequence, thereby enabling an in-depth, unprecedented characterization of functionalized photo-crosslinkable biopolymers. Moreover, our strategy enabled to visualize the spatial distribution of the modifications within the overall structure of the protein. Proteomics has proven to provide unprecedented insight in the distribution of photo-crosslinkable moieties along the protein backbone, undoubtedly contributing to superior functional biomaterial design to serve regenerative medicine.展开更多
CONSPECTUS:A new generation of semiconducting materials based on metal halide perovskites has recently been launched into the scientific spotlight,exhibiting outstanding optoelectronic properties and providing promise...CONSPECTUS:A new generation of semiconducting materials based on metal halide perovskites has recently been launched into the scientific spotlight,exhibiting outstanding optoelectronic properties and providing promise for the development of efficient optical devices.As a vivid example,solar cells made from these materials have quickly reached conversion efficiencies exceeding 25%,now on par with well-established technologies,like silicon.Their widespread success is due,in part,to a unique ability to retain high-quality optoelectronic performance while being easily solutionprocessed into thin films.This feature is what defines them as a brand-new class of optoelectronic materials,with the ability to compete with traditional semiconductors requiring higher processing costs,like the III−Vs or II−IVs.However,the interesting photophysics of metal halide perovskites come with a catch;their soft ionic lattice promotes complex thermal-induced phase transitions and a high capacity for postsynthetic compositional changes,e.g.,halide anion exchange.Such dynamic behavior has ultimately made understanding several important structure−property relationships ambiguous and obstructed a clear path toward commercialization due to inherent phase instability.Our aim in this Account is to highlight the fundamental aspects of metal halide perovskites that dictate a stable crystal structure and enable efficient anion exchange,through the lens of thermodynamic preference and phase formation energies.Taking the allinorganic CsPbI3‑xBrx system as a suitable case study,we focus on several ways in which its thermodynamically unstable perovskite structure can be maintained at room temperature and elucidate the restructuring pathways taken during destabilization.In addition,we will discuss the origin and mechanisms of postsynthetic anion exchange in CsPbX3(X=I,Br,Cl)perovskites,with emphasis made toward direct visualization using in situ optical microspectroscopy and arriving at quantitative results.For several notable features of halide perovskites dealt with in this Account,e.g.,strain stabilization,nonperovskite phase restructuring pathway,and lattice anion diffusion,we attempt to rationalize them using state-of-the-art materials modeling techniques.It is within this spirit that we not only modify a broad range of properties existing within metal halide perovskites but also regulate them for enhanced material functionality.For example,controlling partial phase changes and local replacement of halide composition in CsBX3(B=Pb,Sn and X=I,Br,Cl)nanowires can facilitate the formation of optoelectronic heterojunctions,due to the abrupt change in local crystal structure and the correlated transition in optoelectronic properties.From this combined perspective,metal halide perovskites appear as highly dynamic systems,whereby structural and compositional modifications have a large impact on the underlying phase stability and optoelectronic properties.Thus,we highlight several scientific aspects important to the fundamental understanding of metal halide perovskites,ranging from the underlying mechanism and kinetics through which phase destabilization and anion exchange take place,to tuning the thermodynamic energy landscape using external stimuli.We anticipate that providing a clear perspective for these topics will help deepen our knowledge of the nature of ionic semiconductors and provide the stimulus required to build new research directions toward utilizing halide perovskites within versatile optoelectronic devices.展开更多
Zwitterionic polymers are known to interact with cells and have been shown to reveal cancer cell specificity.In this work,the importance of the chemistry of the polymer backbone for the cellular specificity of amino-a...Zwitterionic polymers are known to interact with cells and have been shown to reveal cancer cell specificity.In this work,the importance of the chemistry of the polymer backbone for the cellular specificity of amino-acid-derived polyzwitterions is demonstrated.A series of glutamic acid(Glu)-based vinyl monomers(i.e.,an acrylate,a methacrylate,an acrylamide,and a methacrylamide)were prepared and used for reversible addition-fragmentation chain-transfer(RAFT)polymerisation,yielding defined polymers with narrow size distribution(Ð<1.3).All Glu-functionalised,zwitterionic polymers revealed high cytocompatibility;however,differences in cellular association and specificity were observed.In particular,the methacrylamide-derived polymers showed high association with both,breast cancer cells and non-cancerous dendritic cells and,consequently,lack specificity.In contrast,high specificity to only breast cancer cells was observed for polyacrylates,-methacrylates,and-acrylamides.Detailed analysis of the polymers revealed differences in hydrophobicity,zeta potential,and potential side chain hydrolysis,which are impacted by the polymer backbone and might be responsible for the altered the cell association of these polymers.It is shown that a slightly negative net charge is preferred over a neutral charge to retain cell specificity.This was also confirmed by association experiments in the presence of competitive amino acid transporter substrates.The affinity of slightly negatively charged Glu-derived polymers to the xCT Glu/cystine cell membrane antiporter was found to be higher than that of neutrally charged polymers.Our results emphasise the importance of the polymer backbone for the design of cell-specific polymers.This study further highlights the potential to tailor amino-acid-derived zwitterionic materials beyond their side chain functionality.展开更多
文摘Objective To explore the relationship between serum chloride levels and prognosis in patients with hepatic coma in the intensive care unit(ICU).Methods We analyzed 545 patients with hepatic coma in the ICU from the Medical Information Mart for Intensive Care IV(MIMIC-IV)database.Associations between serum chloride levels and 28-day and 1-year mortality rates were assessed using restricted cubic splines(RCSs),Kaplan-Meier(KM)curves,and Cox regression.Subgroup analyses,external validation,and mechanistic studies were also performed.Results A total of 545 patients were included in the study.RCS analysis revealed a U-shaped association between serum chloride levels and mortality in patients with hepatic coma.The KM curves indicated lower survival rates among patients with low chloride levels(<103 mmol/L).Low chloride levels were independently linked to increased 28-day and 1-year all-cause mortality rates.In the multivariate models,the hazard ratio(HR)for 28-day mortality in the low-chloride group was 1.424(95%confidence interval[CI]:1.041–1.949),while the adjusted hazard ratio for 1-year mortality was 1.313(95%CI:1.026–1.679).Subgroup analyses and external validation supported these findings.Cytological experiments suggested that low chloride levels may activate the phosphorylation of the NF-κB signaling pathway,promote the expression of pro-inflammatory cytokines,and reduce neuronal cell viability.Conclusion Low serum chloride levels are independently associated with increased mortality in patients with hepatic coma.
基金financially supported by the National Natural Science Foundation of China(Nos.21971177 and 52503155)Natural Science Foundation of the Jiangsu Higher Education Institution of China(No.22KJA150004)+7 种基金China Scholarship Council(No.202206920034)Research Foundation Flanders(FWO)(Application 1S34725N)Priority Academic Program Development(PAPD)of Jiangsu Higher Education InstitutionsJiangsu Key Laboratory of Advanced Functional Polymers Design and ApplicationSoochow UniversitySuzhou Key Laboratory of Macromolecular Design and Precision SynthesisProgram of Innovative Research Team of Soochow Universityfunding from the European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Program 101021081(ERC-AdG-2020,CiMaC-project)。
文摘In this study,dynamic selenonium salts were incorporated into a polyurethane(PU)matrix to develop transparent,healable and antibacterial coatings.Through systematic formulation optimization,optically clear materials with excellent room-temperature hardness were obtained.Fine-tuning the selenonium content established a synergy between antibacterial performance and network dynamics,as evidenced by vitrimer-like rheological behavior at elevated temperatures.Consequently,the coatings exhibited outstanding reprocessability while maintaining high transparency and structural stability after prolonged saltwater exposure.These integrated features underscore the potential of the developed cationic PU coatings as robust,multifunctional materials for electronic device protection and marine antifouling,combining long-term transparency,recyclability,and antibacterial durability.
基金the National Key R&D Program of China(2021YFA1502100)NSFC(Grants Nos.21773031,22011530144,U1805255)+3 种基金Natural Science Foundation of Fujian Province of China(2018J01686)the State Key Laboratory of NBC Protection for Civilian(SKLNBC2020-18)Graphene Powder&Composite Research Center of Fujian Province(2017H2001)financial support from the Research Foundation,Flanders(FWO Grant No.VS052320N)。
文摘CdZnS solid solutions with strong light absorption are promising materials for solar-driven COreduction;however,their relatively weak redox ability and intrinsic photo-corrosion limit their further development as a photocatalyst.The addition of a second photocatalyst with a suitable band structure to construct a S-scheme photocatalytic system can solve both problems simultaneously.Here,we report a S-scheme photocatalyst based on the heterostructure of CoTiO_(3)/CdZnS(abbreviated as CoTiO_(3)/Cd_(9.51)Zn_(0.49)S_(10))that enables the efficient photocatalytic reduction of CO.Detailed physicochemical characterization resolves the S-scheme charge transfer mechanism in this composite photocatalyst.With the well-designed structure of particles and desirable band offsets,this hybrid system offers visible light absorption in a broad spectral region,large surface area,strong redox ability,and fast carrier separation and transportation.Under visible-light illumination,the CoTiO_(3)/Cd Zn S hybrid system displays a CO formation rate of about 11 mmol hgcombined with a long-term operational stability.Besides,a high apparent quantum efficiency(AQE)of 7.27%is realized for the CO_(2)-to-CO reduction reaction by the optimized Co TiO/Cd Zn S hybrid under 420 nm monochromatic light irradiation.
基金Research Foundation—Flanders,Grant/Award Numbers:1242922N,1280021N,12Y7221N,V400622NFlemishgovernment for iBOF funding,Grant/Award Number:PERsist:iBOF-21-085+2 种基金KU Leuven Research Fund,Grant/A ward Number:C14/23/090China Scholarship Council(CSC),Grant/Award Number:201806650002Australian Research Council,Grant/Award Number:DE230100173。
文摘Metal halide perovskite(MHP)quantum dots(QDs)offer immense potentialfor several areas of photonics research due to their easy and low-costfabrication and excellent optoelectronic properties.However,practicalapplications of MHP QDs are limited by their poor stability and,in particular,their tendency to aggregate.Here,we develop a two-step double-solventstrategy to grow and confine CsPbBr_(3)QDs within the three-dimensional(3D)cavities of a mesoporous SBA-16 silica scaffold(CsPbBr_(3)@SBA-16).Strongconfinement and separation of the MHP QDs lead to a relatively uniform sizedistribution,narrow luminescence,and good ambient stability over 2 months.In addition,the CsPbBr_(3)@SBA-16 presents a high activity and stability forvisible-light-driven photocatalytic toluene C(sp^(3))-H bond activation toproduce benzaldehyde with~730 umolg^(-1)h^(-l) yield rate and near-unityselectivity.Similarly,the structural stability of CsPbBr_(3)@SBA-16QDs issuperior to that of both pure CsPbBr3 QDs and those confined in MCM-41with 1D channels.
基金financially supported by the National Natural Science Foundation of China(21902132)the Research Foundation-Flanders(1280021N,1242922N,1298323N)。
文摘Gold(Au)nanostructures(NSs)have been widely employed as cocatalysts to improve the photoactivity of semiconductor materials,while a systematic summary of the engineering approaches of Au NSs to maximize the solar-to-fuel conversion efficiency is still lacking.In this review,the recently developed strategies for elevating the overall photocatalytic performance of Au-based catalysts and the deep physical chemistry mechanisms are highlighted.Firstly,the synthetic approaches of Au NSs are summarized,followed by an elaboration on their multiple functions in improving photoactivity.Afterward,modification strategies of Au NSs used to enhance the photocatalytic efficiency of Au-semiconductor composites,including controlling the Au NSs morphology,size,crystal phase,defect engineering,alloying with different metals,modulating interfacial interaction,and introducing an external field,are summarized and discussed independently.Additionally,advanced characterization techniques that can provide insights into the charge dynamics of the photocatalysts are introduced.Finally,we share our opinion on the challenges and outline potentially promising opportunities and directions for efficient Au-based photocatalysis research moving forward.We sincerely look forward to this review can deliver insightful views to design efficient Au-based photocatalysts and spur certain innovations to other metal-based catalysts.
文摘A promising strategy to support broiler health and performance in a sustainable way is the enhancement of microbial fibre fermentation in broilers.This fermentation mainly occurs in the caeca,but the actual particle size range that allows caecal influx has not yet been described.This study aimed to understand the physical limitations of caecal influx as a function of broiler age by using both solid and soluble markers.In the first trial,the caecal filter mechanism was studied by microscopically visualising the caecal entrance and measuring caecal lobe development and digesta particle size as a function of age(d 8-36)for 44 broilers(Ross 308)receiving a conventional wheat-based diet.In two consecutive trials,microcrystalline cellulose beads(100-700 mm)and a combination of fluorescent polystyrene beads(5-30 mm)and chromium-ethylenediamine tetraacetic acid(Cr-EDTA)were administered to 176 and 189 broilers,respectively,at different ages(d 8-36).Results showed that the actual caecal entrance diameter is significantly reduced due to a dense villi network acting as a filter for digesta inflow.This explains the size gap between the average digesta particle size(D50)of the ileum(451-322 mm)and caeca(5-19 mm),and the outer diameter of the caecal entrance(2000-4000 mm)on d 8 to 36.In contrast to the caecal D50,cellulose beads of 700 mm already entered the caeca at 8 d of age,even though the general caecal influx of digesta particles larger than 100 mm seemed very limited.The caecal influx of the markers further exhibited large individual variation among birds.A maximum of 13.2%(d 9)and 4.3%(d 29)of the total administered soluble marker(Cr-EDTA)was detected in the caeca,5 h after bolus administration.Both solid and soluble markers showed a larger concentration in the caeca at a young age compared to older ages(P<0.01),possibly related to the limited caecal functioning early in life.These findings highlight the importance of carefully selecting the physical properties of fibres to be added as a function of age to further improve caecal fibre fermentation in broilers.
基金supported by the National Natural Science Foundation of China(Nos.21902132,91934303,21390391,21473193,21673198,and 21621091)the Award Program for Minjiang Scholar Professorship,the National Key Research and Development Program of China(No.2017YFA0206500)+2 种基金the European Union’s Horizon 2020 research and innovation programme under the Marie Sktodowska-Curie grant agreement No.891276,Research Foundation-Flanders(FWO,No.128002IN)the KU Leuven Research Fund(C14/15/053 and C14/19/079)the European Union(Horizon 2020)Marie Sklodowska-Curie innovation program(No.722591).
文摘Ultrasmall gold(Au)clusters have been regarded as one of the prototypes materials for solar energy conversion due to their unique strong molecular-like light absorption properties.However,the light-induced aggregation of Au clusters into nanoparticles is one of the most important factors that restricts its application in photocatalysis.Although Au clusters aggregation has been widely demonstrated,the underlying mechanism for cluster fusion is still unclear due to the lack of experimental evidence.Herein,we report the direct observation of Au clusters on TiO_(2) nanosheets aggregating when used as visible light photocatalysts for the reduction of nitroaromatics.Through in situ high-resolution transmission electron microscopy(TEM),the coexistence of two fusion mechanisms of Au clusters on TiO_(2) under ultraviolet-visible(UV-Vis)light irradiation in air is identified,i.e.,the migration and coalescence(MC)and Ostwald ripening(OR).Additionally,the correlation between the photostability of Au clusters and reaction atmospheres has been investigated,among which Au clusters have higher stability in an inert N_(2) atmosphere or vacuum than the oxidizing atmospheres(i.e.,air and O_(2)).These results indicate the inherent stability of Au cluster during photocatalysis,and instability comes from the consuming of ligand layer.This work not only discloses the underlying mechanism of Au cluster sintering but also provides guidelines for enhancing metal clusters-based photocatalysts stability.
基金The authors acknowledge the IBiSA network for financial support of the USR 3290(MSAP)proteomics facility TOP_OMICS.The mass spec-trometers were funded by the University of Lille,the CNRS,the Region Hauts-de-France and the European Regional Development Fund (ERDF).
文摘The distribution of photo-crosslinkable moieties onto a protein backbone can affect a biomaterial’s crosslinking behavior, and therefore also its mechanical and biological properties. A profound insight in this respect is essential for biomaterials exploited in tissue engineering and regenerative medicine. In the present work, photo-crosslinkable moieties have been introduced on the primary amine groups of: (i) a recombinant collagen peptide (RCPhC1) with a known amino acid (AA) sequence, and (ii) bovine skin collagen (COL BS) with an unknown AA sequence. The degree of substitution (DS) was quantified with two conventional techniques: an ortho-phthalic dialdehyde (OPA) assay and ^(1)H NMR spectroscopy. However, neither of both provides information on the exact type and location of the modified AAs. Therefore, for the first time, proteomic analysis was evaluated herein as a tool to identify functionalized AAs as well as the exact position of photo-crosslinkable moieties along the AA sequence, thereby enabling an in-depth, unprecedented characterization of functionalized photo-crosslinkable biopolymers. Moreover, our strategy enabled to visualize the spatial distribution of the modifications within the overall structure of the protein. Proteomics has proven to provide unprecedented insight in the distribution of photo-crosslinkable moieties along the protein backbone, undoubtedly contributing to superior functional biomaterial design to serve regenerative medicine.
基金J.A.S.acknowledges financial support from the Research Foundation-Flanders(FWO:grant nos.12Y7218N and V439819N)This work was supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division,under Contract DE-AC02-05-CH11231 within the Physical Chemistry of Inorganic Nanostructures Program(KC3103).M.L.and Y.Z.acknowledge the fellowship support from Suzhou Industrial Park.J.H.and M.B.J.R.acknowledge financial support from the Research Foundation-Flanders(FWO)through research projects(FWO Grant No’s G098319N and ZW15_09-GOH6316)from the Flemish government through long term structural funding Methusalem(CASAS2,Meth/15/04)。
文摘CONSPECTUS:A new generation of semiconducting materials based on metal halide perovskites has recently been launched into the scientific spotlight,exhibiting outstanding optoelectronic properties and providing promise for the development of efficient optical devices.As a vivid example,solar cells made from these materials have quickly reached conversion efficiencies exceeding 25%,now on par with well-established technologies,like silicon.Their widespread success is due,in part,to a unique ability to retain high-quality optoelectronic performance while being easily solutionprocessed into thin films.This feature is what defines them as a brand-new class of optoelectronic materials,with the ability to compete with traditional semiconductors requiring higher processing costs,like the III−Vs or II−IVs.However,the interesting photophysics of metal halide perovskites come with a catch;their soft ionic lattice promotes complex thermal-induced phase transitions and a high capacity for postsynthetic compositional changes,e.g.,halide anion exchange.Such dynamic behavior has ultimately made understanding several important structure−property relationships ambiguous and obstructed a clear path toward commercialization due to inherent phase instability.Our aim in this Account is to highlight the fundamental aspects of metal halide perovskites that dictate a stable crystal structure and enable efficient anion exchange,through the lens of thermodynamic preference and phase formation energies.Taking the allinorganic CsPbI3‑xBrx system as a suitable case study,we focus on several ways in which its thermodynamically unstable perovskite structure can be maintained at room temperature and elucidate the restructuring pathways taken during destabilization.In addition,we will discuss the origin and mechanisms of postsynthetic anion exchange in CsPbX3(X=I,Br,Cl)perovskites,with emphasis made toward direct visualization using in situ optical microspectroscopy and arriving at quantitative results.For several notable features of halide perovskites dealt with in this Account,e.g.,strain stabilization,nonperovskite phase restructuring pathway,and lattice anion diffusion,we attempt to rationalize them using state-of-the-art materials modeling techniques.It is within this spirit that we not only modify a broad range of properties existing within metal halide perovskites but also regulate them for enhanced material functionality.For example,controlling partial phase changes and local replacement of halide composition in CsBX3(B=Pb,Sn and X=I,Br,Cl)nanowires can facilitate the formation of optoelectronic heterojunctions,due to the abrupt change in local crystal structure and the correlated transition in optoelectronic properties.From this combined perspective,metal halide perovskites appear as highly dynamic systems,whereby structural and compositional modifications have a large impact on the underlying phase stability and optoelectronic properties.Thus,we highlight several scientific aspects important to the fundamental understanding of metal halide perovskites,ranging from the underlying mechanism and kinetics through which phase destabilization and anion exchange take place,to tuning the thermodynamic energy landscape using external stimuli.We anticipate that providing a clear perspective for these topics will help deepen our knowledge of the nature of ionic semiconductors and provide the stimulus required to build new research directions toward utilizing halide perovskites within versatile optoelectronic devices.
文摘Zwitterionic polymers are known to interact with cells and have been shown to reveal cancer cell specificity.In this work,the importance of the chemistry of the polymer backbone for the cellular specificity of amino-acid-derived polyzwitterions is demonstrated.A series of glutamic acid(Glu)-based vinyl monomers(i.e.,an acrylate,a methacrylate,an acrylamide,and a methacrylamide)were prepared and used for reversible addition-fragmentation chain-transfer(RAFT)polymerisation,yielding defined polymers with narrow size distribution(Ð<1.3).All Glu-functionalised,zwitterionic polymers revealed high cytocompatibility;however,differences in cellular association and specificity were observed.In particular,the methacrylamide-derived polymers showed high association with both,breast cancer cells and non-cancerous dendritic cells and,consequently,lack specificity.In contrast,high specificity to only breast cancer cells was observed for polyacrylates,-methacrylates,and-acrylamides.Detailed analysis of the polymers revealed differences in hydrophobicity,zeta potential,and potential side chain hydrolysis,which are impacted by the polymer backbone and might be responsible for the altered the cell association of these polymers.It is shown that a slightly negative net charge is preferred over a neutral charge to retain cell specificity.This was also confirmed by association experiments in the presence of competitive amino acid transporter substrates.The affinity of slightly negatively charged Glu-derived polymers to the xCT Glu/cystine cell membrane antiporter was found to be higher than that of neutrally charged polymers.Our results emphasise the importance of the polymer backbone for the design of cell-specific polymers.This study further highlights the potential to tailor amino-acid-derived zwitterionic materials beyond their side chain functionality.
