Three-dimensional(3D)printing has gained popularity in a variety of applications,particularly in the manufacture of wearable devices.Aided by the large degree of freedom in customizable fabrication,3D printing can cat...Three-dimensional(3D)printing has gained popularity in a variety of applications,particularly in the manufacture of wearable devices.Aided by the large degree of freedom in customizable fabrication,3D printing can cater towards the practical requirements of wearable devices in terms of light weight and flexibility.In particular,this focus review aims to cover the important aspect of wearable energy storage devices(WESDs),which is an essential component of most wearable devices.Herein,the topics discussed are the fundamentals of 3D printing inks used,the optimizing strategies in improving the mechanical and electrochemical properties of wearable devices and the recent developments and challenges of wearable electrochemical systems such as batteries and supercapacitors.It can be expected that,with the development of 3D printing technology,realization of the full potential of WESDs and seamless integration into smart devices also needs further in-depth investigations.展开更多
Thermoelectric generators(TEGs)have received increasing attention due to their potential to harvest low-grade heat energy(<100℃ )and provide power for the Internet of Things(IoT)and wearable electronic devices.Her...Thermoelectric generators(TEGs)have received increasing attention due to their potential to harvest low-grade heat energy(<100℃ )and provide power for the Internet of Things(IoT)and wearable electronic devices.Herein,a wood-based ordered framework is used to fabricate carbon nanotube/poly(3,4-ethylenedioxythiophene)(CNT/PEDOT)wood aerogel for TEG.The prepared CNT/PEDOT wood aerogel with an anisotropic structure exhibits a low thermal conductivity of 0.17 W m^(−1)K^(−1)and is advantageous to develop a sufficient temperature gradient.Meanwhile,CNT/PEDOT composites effectively decouple the relationship between the Seebeck coefficient and electrical conductivity by energy filtering effect to enhance thermoelectric(TE)output properties.The vertical TEG assembled by the CNT/PEDOT wood aerogels reveals an output power of 1.5μW and a mass-specific power of 15.48μW g^(−1)at a temperature difference of 39.4 K.Moreover,the layered structure renders high compressibility and fatigue resistance.The anisotropic structure,high mechanical performance,and rapid thermoelectric response,enabling the TEG based on CNT/PEDOT wood aerogel offer opportunities for continuous power supply to low-power electronic devices.展开更多
Carbon aerogels prepared from renewable nano building blocks are rising-star materials and hold great promise in many fields.However,various defects formed during carbonization at high temperature disfavor the stress ...Carbon aerogels prepared from renewable nano building blocks are rising-star materials and hold great promise in many fields.However,various defects formed during carbonization at high temperature disfavor the stress transfer and thus the fabrication of flexible carbon aerogel from renewable nano building blocks.Herein,a structural defect-reducing strategy is proposed by altering the pyrolysis route of cellulose nanofiber.Inorganic salt that inhibits the generation of tar volatilization during pyrolysis can prevent the formation of various structural defects.Microstructure with fewer defects can reduce stress concentration and remarkably enhance the compressibility of carbon aerogel,thus increasing the maximum stress retention of carbon aerogel.The carbon aerogel also has high stress sensor sensitivity and excellent temperature coefficient of resistance.The structural defect-reducing strategy will pave a new way to fabricate high-strength carbon materials for various fields.展开更多
Insulin-like growth factor-1(IGF-1)is considered as a pathogenic factor contributing to sebaceous gland dysfunction,which leads to acne vulgaris.Paeoniflorin(Pae),a bioactive monomer derived from total glycosides of p...Insulin-like growth factor-1(IGF-1)is considered as a pathogenic factor contributing to sebaceous gland dysfunction,which leads to acne vulgaris.Paeoniflorin(Pae),a bioactive monomer derived from total glycosides of paeony,has shown potential in treating various diseases.However,its anti-acne effects on human sebocytes are not well understood.In this study,we investigated the effects of Pae on acne development induced by IGF-1 in SZ95 sebocytes.Following IGF-1 stimulation,SZ95 sebocytes were exposed to Pae and then determined for proliferation,cell cycle,apoptosis,lipogenesis and pro-inflammatory cytokine secretion.We also analyzed the expression of proteins involved in the PI3K/Akt/FoxO1 and JAK2/STAT3 pathways.In vitro experiments demonstrated that Pae significantly inhibited colony formation,induced G1/S cell cycle arrest,promoted apoptosis,inhibited lipogenesis and cytokine synthesis in IGF-1-treated SZ95 sebocytes.Furthermore,Pae suppressed the phosphorylation of Akt,FoxO1,JAK2,and STAT3.Importantly,the sebo-suppressive and anti-inflammatory effects of Pae were enhanced by blocking PI3K and JAK2.In summary,our findings suggest that Pae has potent anti-proliferative and pro-apoptotic effects in SZ95 sebocytes.Additionally,Pae effectively protects against IGF-1-induced lipogenesis and inflammation by targeting the PI3K/Akt/FoxO1 and JAK2/STAT3 signaling pathways.展开更多
Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products.CoSe_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separati...Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products.CoSe_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separation of photogenerated electron–holes,increase the reaction rates,and enhance photocatalytic efficiency.In this work,we synthesized a stable and efficient photocatalysis system of CoSe_(2)/g-C_(3)N_(4)through attaching CoSe_(2)on g-C_(3)N_(4)sheets,with a yield of 50.12%for the selective photooxidation of xylose to xylonic acid.Under light illumination,the photogenerated electrons were prone to migrating from g-C_(3)N_(4)to CoSe_(2)due to the higher work function of CoSe_(2),resulting in the accelerated separation of photogenerated electron–holes and the promoted photooxidation.Herein,this study reveals the unique function of CoSe_(2),which can significantly promote oxygen adsorption,work as an electron sink and accelerate the generation of ·O_(2)^(-),thereby improving the selectivity toward xylonic acid over other by-products.This work provides useful insights into the design of selective photocatalysts by engineering g-C_(3)N_(4)for biomass high-value utilization.展开更多
Hashtags of microblogs can provide valuable information for many natural language processing tasks. How to recommend reliable hashtags automatically has attracted considerable attention. However, existing studies assu...Hashtags of microblogs can provide valuable information for many natural language processing tasks. How to recommend reliable hashtags automatically has attracted considerable attention. However, existing studies assumed that all the training corpus crawled from social networks are labelled correctly, while large sample statistics on real social media shows that there are 8.9% of microblogs with hashtags having wrong labels. The notable influence of noisy data to the classifier is ignored before. Meanwhile, recency also plays an important role in microblog hashtag, but the information is not used in the existing studies. Some temporal hashtags such as World Cup will ignite at a particular time, but at other times, the number of people talking about it will sharply decrease. To address the twofold shortcomings above, the authors propose an long short-term memory-based model, which uses temporal enhanced selective sentence-level attention to reduce the influence of wrong labelled microblogs to the classifier. Experimental results using a dataset of 1.7 million microblogs collected from SINA Weibo microblogs demonstrated that the proposed method could achieve significantly better performance than the state-of-the-art methods.展开更多
The switchable cross-coupling of indoles and pyridotriazoles through carbene insertion at C_(2)-or C_(3)-positon has been developed in this paper.This highly site-selective C-H carbenoid functionalization is determine...The switchable cross-coupling of indoles and pyridotriazoles through carbene insertion at C_(2)-or C_(3)-positon has been developed in this paper.This highly site-selective C-H carbenoid functionalization is determined by both the Rh-catalyst species and auxiliary groups.[Cp∗RhCl_(2)]_(2) and coordinating pyrimidyl group direct the C-H carbenoid functionalization to occur at the C_(2)-position,while Rh2OAc4 and noncoordinating benzyl group lead the reaction to occur at the C_(3)-position of the indoles.This regioselective C−H functionalization strategy is of significant importance for the discovery of indole drugs.展开更多
A series of optically active copolymers with various feed ratios have been synthesized through helix-sense-selective copolymerization catalyzed by[Rh(norbornadiene)Cl]2-triethylamine.This process involves two proline-...A series of optically active copolymers with various feed ratios have been synthesized through helix-sense-selective copolymerization catalyzed by[Rh(norbornadiene)Cl]2-triethylamine.This process involves two proline-derived acetylene monomers,(S)-N-(4-chlorophenyl)carbamoyl-2-ethynyl pyrrolidine(MCl)and(S)-N-(tert-butoxycarbonyl)-2-ethynyl pyrrolidine,followed by acidic deprotection and neutralization.These copolymers adopt helical conformations with a preferred handedness,as demonstrated by nuclear magnetic resonance spectroscopy and a series of spectroscopic analyses.The chiroptical activity intensity of copolymer has been found to increase with MCl content.Consequently,the enantioseparation capabilities of copolymers containing 95 mol%,90 mol%,and 85 mol%MCl units have been assessed as chiral stationary phases in high-performance liquid chromatography because of their good chiroptical activities.These chiral stationary phases effectively enantioseparate racemic alcohols,sulfoxides,amides,and metal complexes.Notably,the copolymer with 90 mol%MCl shows superior chiral recognition ability,especially for 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanol(α=1.19)and 4-methylbenzenesulfinamide(α=1.47).Insights from molecular dynamic simulation and autodock analysis indicate that hydrogen bonding andπ-πstacking interactions between the chiral stationary phases and enantiomers play a key role for successful chiral separation.Our contribution not only demonstrates the importance of hydrogen bonding donor and copolymer chiroptical activity of chiral stationary phases for chiral resolution,but will also provide valuable insights for the future development of novel stationary phases.展开更多
Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China.Because of its nitrogen-fixing ability,it can play a positive role in soil and forest re...Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China.Because of its nitrogen-fixing ability,it can play a positive role in soil and forest restoration.After clearcutting of planted stands,R.pseudoacacia stands become coppice plantations.The impacts of shifting from seedling to coppice stands on soil bacterial community and soil properties have not been wel described.This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands.Methods:Nine 20 m×20 m plots were randomly selected in seedling and coppice stands.The bulk soil and rhizosphere soil were sampled in summer 2017.Bulk soil was sampled at 10 cm from the soil surface using a soil auger.Rhizosphere soil samples were col ected using a brush.The soil samples were transported to the laboratory for chemical analysis,and bacterial community composition and diversity was obtained through DNA extraction,16 S r RNA gene amplification and high-throughput sequencing.Results:The results showed that,compared to seedling plantations,soil quality decreased significantly in coppice stands,but without affecting soil exchangeable Mg^(2+)and K^(+).Total carbon(C)and nitrogen(N)were lower in the rhizosphere than in bulk soil,whereas nutrient availability showed an opposite trend.The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterialα-diversity.Principal component analysis(PCA)showed that bacterial community composition was similar in both bulk and rhizosphere soils in second-generation coppice plantations.Special y,the conversion from seedling to coppice stands increased the relative abundance of Proteobacteria and Rhizobium,but reduced that of Actinobacteria,which may result in a decline of soil nutrient availability.Mantel tests revealed that C,N,soil organic matter(SOM),nitrate nitrogen(NO^(-)+(3)-N)and available phosphorus positively correlated with bacterial community composition,while a variation partition analysis(VPA)showed that NO^(-)+(3)-N explained a relatively greater proportion of bacterial distribution(15.12%),compared with C and SOM.Surprisingly,N showed no relationship with bacterial community composition,which may be related to nitrogen transportation.Conclusions:The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils.Such imbalance in microbial structure can accelerate the decline of R.pseudoacacia.This may affect the role of R.pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas.展开更多
Electrochemistry has emerged as a major route for graphene and graphene oxide synthesis from graphite.Anodic graphite oxidation is commonly used with dilute mineral acid or aqueous salt electrolytes.In this system,the...Electrochemistry has emerged as a major route for graphene and graphene oxide synthesis from graphite.Anodic graphite oxidation is commonly used with dilute mineral acid or aqueous salt electrolytes.In this system,the electrolyte acid concentration appears to be a critical parameter.However,the effect of the acid concentration,particularly at low concentrations,is still not fully understood.To address this issue,we used a packed bed electrochemical reactor to synthesize seven different electrochemical graphite oxide(EGO)products in 2–16M sulfuric acid.Detailed XRD,XPS,Raman,conductivity and optical microscopy analysis of the products was carried out.We found dilute acid(<10 M)graphite oxides were less crystalline and less oxidized than those produced in stronger acids.The oxygen evolution reaction at the graphite surface appears to affect the structural changes,oxidation mechanism,and electrochemical corrosion of the anode.EGO conductivity is also strongly affected by the electrolyte’s acidity.We show that well oxidized,yet reasonably conductive,single layer graphene oxide can be produced from 7.1M acid.These results broaden our understanding of graphite electrochemistry and will serve to inform future electrochemical graphene synthesis efforts.展开更多
The separator is an essential component of sodium-ion batteries(SIBs)to determine their electrochemical performances.However,the separator with high mechanical strength,good electrolyte wettability and excellent elect...The separator is an essential component of sodium-ion batteries(SIBs)to determine their electrochemical performances.However,the separator with high mechanical strength,good electrolyte wettability and excellent electrochemical performance remains an open challenge.Herein,a new separator consisting of amphoteric nanofibers with abundant functional groups was fabricated through supramolecular assembly of natural polymers for SIB.The uniform nanoporous structure,remarkable mechanical properties and abundant functional groups(e.g.-COOH,-NH_(2)and-OH)endow the separator with lower dissolution activation energy and higher ion migration numbers.These metrics enable the separator to lower the barrier for desolvation of Na^(+),accelerate the migration of Na^(+),and generate more stable solid electrolyte interphase(SEI)and cathode electrolyte interphase(CEI).The battery assembled with the amphoteric nanofiber separator shows higher specific capacity and better stability than that assembled with glass fiber(GF)separator.展开更多
Liquid metal(LM)and liquid metal alloys(LMs)possess unique physicochemical features,which have become emerging and functionalized materials that are attractive applicants in various fields.Herein,uniform LM nanodrople...Liquid metal(LM)and liquid metal alloys(LMs)possess unique physicochemical features,which have become emerging and functionalized materials that are attractive applicants in various fields.Herein,uniform LM nanodroplets armored by carbon dots(LMD@CDs)were prepared and exhibited high colloidal stability in various solvents,as well as water.After optimization,LMD@CDs can be applied as functional additives for the 3D/4D printing of hydrogel and cross-linked resin through digital light processing(DLP).The light absorption of LMD@CDs not only improved the printing accuracy,but also led to the cross-linking density differential during the post-curing process.Base on the cross-linking density differential of soft hydrogel and photothermal performance of the LM,the 3D printed objects can exhibit stimulus responses to both water and laser irradiation.Additionally,the CDs shell and LM core of LMD@CDs provide the printed objects interesting photoluminescence and electric conductivity capabilities,respectively.We deduce this versatile 3D/4D printing system would provide a new platform for the preparation of multi-functional and stimuli-responsive advance materials.展开更多
Fruit flies usually harbor diverse communities of bacteria in their digestive systems,which are known to play a significant role in their fitness.However,little information is available on Zeugodacus tau,a polyphagous...Fruit flies usually harbor diverse communities of bacteria in their digestive systems,which are known to play a significant role in their fitness.However,little information is available on Zeugodacus tau,a polyphagous pest worldwide.This study reports the first extensive analysis of bacterial communities in different life stages and their effect on the development and reproduction of laboratory-reared Z tan.Cultured bacteria were identified using the conventional method and all bacteria were identified by highthroughput technologies(16S ribosomal RNA gene sequencing of V3-V4 region).A total of six bacterial phyla were identified in larvae,pupae,and male and female adult flies,which were distributed into 14 classes,32 orders,58 families and 96 genera.Proteobacteria was the most represented phylum in all the stages except larvae.Enterobacter,Klebsiella,Providencia,and Pseudomonas were identified by conventional and next-generation sequencing analysis in both male and female adult flies,and Enterobacter was found to be the main genus.After being fed with antibiotics from the first instar larvae,bacterial diversity changed markedly in the adult stage.Untreated flies laid eggs and needed 20 days before oviposition while the treated flies showed ovary development inhibited and were not able to lay eggs,probably due to the alteration of the microbiota.These findings provide the cornerstone for unexplored research on bacterial function in Z tau,which will help to develop an environmentally friendly management technique for this kind of harmful insect.展开更多
Image emotion classification(IEC)aims to extract the abstract emotions evoked in images.Recently,language-supervised methods such as con-trastive language-image pretraining(CLIP)have demonstrated superior performance ...Image emotion classification(IEC)aims to extract the abstract emotions evoked in images.Recently,language-supervised methods such as con-trastive language-image pretraining(CLIP)have demonstrated superior performance in image under-standing.However,the underexplored task of IEC presents three major challenges:a tremendous training objective gap between pretraining and IEC,shared suboptimal prompts,and invariant prompts for all instances.In this study,we propose a general framework that effectively exploits the language-supervised CLIP method for the IEC task.First,a prompt-tuning method that mimics the pretraining objective of CLIP is introduced,to exploit the rich image and text semantics associated with CLIP.Subsequently,instance-specific prompts are automatically composed,conditioning them on the categories and image content of instances,diversifying the prompts,and thus avoiding suboptimal problems.Evaluations on six widely used affective datasets show that the proposed method significantly outperforms state-of-the-art methods(up to 9.29%accuracy gain on the EmotionROI dataset)on IEC tasks with only a few trained parameters.The code is publicly available at https://github.com/dsn0w/PT-DPC/for research purposes.展开更多
This study established back-propagation neural networks(BPNNs)for evaluating the freshness of bighead carp(Hypophthalmichthys nobilis)heads during chilled storage via fluorescence spectroscopy using an excitation-emis...This study established back-propagation neural networks(BPNNs)for evaluating the freshness of bighead carp(Hypophthalmichthys nobilis)heads during chilled storage via fluorescence spectroscopy using an excitation-emission matrix(EEM).The total volatile basic nitrogen(TVB-N)and total aerobic count(TAC)of fish increased obviously during storage at 0,4,8,12,and 16°C,while sensory scores decreased with increasing storage time.The EEM fluorescence intensity was measured,and its change was correlated with the freshness indicators of the samples.Three characteristic components of EEM data were extracted by parallel factor analysis,and two freshness indicators were used to construct the EEM-BPNNs model.The results demonstrated that the relative errors of the EEM-BPNNs model for TVB-N and TAC were less than 14%.This result indicated that the EEM-BPNNs model could determine the freshness of fish in cold chains in a rapid and nondestructive way.展开更多
Diabetic wounds are a difficult medical challenge.Excessive secretion of matrix metalloproteinase-9(MMP-9)in diabetic wounds further degrades the extracellular matrix and growth factors and causes severe vascular dama...Diabetic wounds are a difficult medical challenge.Excessive secretion of matrix metalloproteinase-9(MMP-9)in diabetic wounds further degrades the extracellular matrix and growth factors and causes severe vascular damage,which seriously hinders diabetic wound healing.To solve these issues,a double-network porous hydrogel composed of poly(methyl methacrylate-co-acrylamide)(p(MMA-co-AM))and polyvinyl alcohol(PVA)was constructed by the high internal phase emulsion(HIPE)technique for the delivery of potassium sucrose octasulfate(PSO),a drug that can inhibit MMPs,increase angiogenesis and improve microcirculation.The hydrogel possessed a typical polyHIPE hierarchical microstructure with interconnected porous morphologies,high porosity,high specific surface area,excellent mechanical properties and suitable swelling properties.Meanwhile,the p(MMA-co-AM)/PVA@PSO hydrogel showed high drug-loading performance and effective PSO release.In addition,both in vitro and in vivo studies showed that the p(MMA-co-AM)/PVA@PSO hydrogel had good biocompatibility and significantly accelerated diabetic wound healing by inhibiting excessive MMP-9 in diabetic wounds,increasing growth factor secretion,improving vascularization,increasing collagen deposition and promoting re-epithelialization.Therefore,this study provided a reliable therapeutic strategy for diabetic wound healing,some theoretical basis and new insights for the rational design and preparation of wound hydrogel dressings with high porosity,high drug-loading performance and excellent mechanical properties.展开更多
The urban spatial structure reflects a city’s development history,cultural heritage,and socio-economic conditions.A rational urban spatial structure is crucial for urban development.This study focuses on the main urb...The urban spatial structure reflects a city’s development history,cultural heritage,and socio-economic conditions.A rational urban spatial structure is crucial for urban development.This study focuses on the main urban area of Nanjing,analyzing POI and nighttime light data from 2016 to 2020.Utilizing kernel density estimation and coupling coordination models,it explores the temporal and spatial evolution characteristics of Nanjing’s urban spatial structure.Geographic detectors are employed to assess the impact of various factors on this structure.The findings indicate that:(1)Nanjing’s urban spatial structure displays a pattern of central aggregation and peripheral expansion,with high brightness concentrated in the urban center and a significant increase in peripheral brightness,signaling initial success in establishing urban subcenters;(2)The coupling relationship between nighttime light brightness and POI density has strengthened,suggesting improved coordination of the urban spatial structure;(3)The evolution of Nanjing’s urban spatial structure results from the combined effects of multiple factors,including economic level,population distribution,transportation conditions,and policy planning.展开更多
With the rapid development of wearable and intelligent flexible electronic devices(FEDs),the demand for flexible energy storage/conversion devices(ESCDs)has also increased.Rechargeable flexible metal‐air batteries(MA...With the rapid development of wearable and intelligent flexible electronic devices(FEDs),the demand for flexible energy storage/conversion devices(ESCDs)has also increased.Rechargeable flexible metal‐air batteries(MABs)are expected to be one of the most ideal ESCDs due to their high theoretical energy density,cost advantage,and strong deformation adaptability.With the improvement of the device design,material assemblies,and manufacturing technology,the research on the electrochemical performance of flexible MABs has made significant progress.However,achieving the high mechanical flexibility,high safety,and wearable comfortability required by FEDs while maintaining the high performance of flexible MABs are still a daunting challenge.In this review,flexible Zn‐air and Li‐air batteries are mainly exemplified to describe the most recent progress and challenges of flexible MABs.We start with an overview of the structure and configuration of the flexible MABs and discuss their impact on battery performance and function.Then it focuses on the research progress of flexible metal anodes,gel polymer electrolytes,and air cathodes.Finally,the main challenges and future research perspectives involving flexible MABs for FEDs are proposed.展开更多
基金Australian Research Council,Grant/Award Numbers:DP190100120,FT200100015。
文摘Three-dimensional(3D)printing has gained popularity in a variety of applications,particularly in the manufacture of wearable devices.Aided by the large degree of freedom in customizable fabrication,3D printing can cater towards the practical requirements of wearable devices in terms of light weight and flexibility.In particular,this focus review aims to cover the important aspect of wearable energy storage devices(WESDs),which is an essential component of most wearable devices.Herein,the topics discussed are the fundamentals of 3D printing inks used,the optimizing strategies in improving the mechanical and electrochemical properties of wearable devices and the recent developments and challenges of wearable electrochemical systems such as batteries and supercapacitors.It can be expected that,with the development of 3D printing technology,realization of the full potential of WESDs and seamless integration into smart devices also needs further in-depth investigations.
基金supported by the National Natural Science Foundation of China(No.32071714)Guangzhou Science and Technology project(No.202002030167)Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110910)。
文摘Thermoelectric generators(TEGs)have received increasing attention due to their potential to harvest low-grade heat energy(<100℃ )and provide power for the Internet of Things(IoT)and wearable electronic devices.Herein,a wood-based ordered framework is used to fabricate carbon nanotube/poly(3,4-ethylenedioxythiophene)(CNT/PEDOT)wood aerogel for TEG.The prepared CNT/PEDOT wood aerogel with an anisotropic structure exhibits a low thermal conductivity of 0.17 W m^(−1)K^(−1)and is advantageous to develop a sufficient temperature gradient.Meanwhile,CNT/PEDOT composites effectively decouple the relationship between the Seebeck coefficient and electrical conductivity by energy filtering effect to enhance thermoelectric(TE)output properties.The vertical TEG assembled by the CNT/PEDOT wood aerogels reveals an output power of 1.5μW and a mass-specific power of 15.48μW g^(−1)at a temperature difference of 39.4 K.Moreover,the layered structure renders high compressibility and fatigue resistance.The anisotropic structure,high mechanical performance,and rapid thermoelectric response,enabling the TEG based on CNT/PEDOT wood aerogel offer opportunities for continuous power supply to low-power electronic devices.
基金the National Natural Science Foundation of China(Nos.32201499,22208069 and 32071714)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110205)+1 种基金Fundamental Research Funds for the Central Universities(No.2022ZYGXZR019)the State Key Laboratory of Pulp&Paper Engineering(No.2022C01).
文摘Carbon aerogels prepared from renewable nano building blocks are rising-star materials and hold great promise in many fields.However,various defects formed during carbonization at high temperature disfavor the stress transfer and thus the fabrication of flexible carbon aerogel from renewable nano building blocks.Herein,a structural defect-reducing strategy is proposed by altering the pyrolysis route of cellulose nanofiber.Inorganic salt that inhibits the generation of tar volatilization during pyrolysis can prevent the formation of various structural defects.Microstructure with fewer defects can reduce stress concentration and remarkably enhance the compressibility of carbon aerogel,thus increasing the maximum stress retention of carbon aerogel.The carbon aerogel also has high stress sensor sensitivity and excellent temperature coefficient of resistance.The structural defect-reducing strategy will pave a new way to fabricate high-strength carbon materials for various fields.
基金supported by the National Natural Science Foundation of China(Project No.81773345 and 82104856)Basic and Applied Basic Research Foundation of Guangdong Province(No.SL2023A04J01298).
文摘Insulin-like growth factor-1(IGF-1)is considered as a pathogenic factor contributing to sebaceous gland dysfunction,which leads to acne vulgaris.Paeoniflorin(Pae),a bioactive monomer derived from total glycosides of paeony,has shown potential in treating various diseases.However,its anti-acne effects on human sebocytes are not well understood.In this study,we investigated the effects of Pae on acne development induced by IGF-1 in SZ95 sebocytes.Following IGF-1 stimulation,SZ95 sebocytes were exposed to Pae and then determined for proliferation,cell cycle,apoptosis,lipogenesis and pro-inflammatory cytokine secretion.We also analyzed the expression of proteins involved in the PI3K/Akt/FoxO1 and JAK2/STAT3 pathways.In vitro experiments demonstrated that Pae significantly inhibited colony formation,induced G1/S cell cycle arrest,promoted apoptosis,inhibited lipogenesis and cytokine synthesis in IGF-1-treated SZ95 sebocytes.Furthermore,Pae suppressed the phosphorylation of Akt,FoxO1,JAK2,and STAT3.Importantly,the sebo-suppressive and anti-inflammatory effects of Pae were enhanced by blocking PI3K and JAK2.In summary,our findings suggest that Pae has potent anti-proliferative and pro-apoptotic effects in SZ95 sebocytes.Additionally,Pae effectively protects against IGF-1-induced lipogenesis and inflammation by targeting the PI3K/Akt/FoxO1 and JAK2/STAT3 signaling pathways.
基金financial support by National Key Research and Development Project(Grant No.2023YFE0109600)Guangzhou Key Research and Development Program(Grant No.2023B03J1330)+5 种基金National Program for Support of Topnotch Young Professionals(Grant No.x2qsA4210090)Guangzhou Basic and Applied Basic Research Foundation(Grant No.2024A04J3413)National Natural Science Foundation of China(Grant No.32201499)State Key Laboratory of Pulp and Paper Engineering(Grant Nos.2023PY01 and 202215)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515012519 and 2023B1515040013)China Postdoctoral Science Foundation(Grant No.2023M732021).
文摘Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products.CoSe_(2)is a promising nonprecious,efficient cocatalyst for photooxidation,which can facilitate the separation of photogenerated electron–holes,increase the reaction rates,and enhance photocatalytic efficiency.In this work,we synthesized a stable and efficient photocatalysis system of CoSe_(2)/g-C_(3)N_(4)through attaching CoSe_(2)on g-C_(3)N_(4)sheets,with a yield of 50.12%for the selective photooxidation of xylose to xylonic acid.Under light illumination,the photogenerated electrons were prone to migrating from g-C_(3)N_(4)to CoSe_(2)due to the higher work function of CoSe_(2),resulting in the accelerated separation of photogenerated electron–holes and the promoted photooxidation.Herein,this study reveals the unique function of CoSe_(2),which can significantly promote oxygen adsorption,work as an electron sink and accelerate the generation of ·O_(2)^(-),thereby improving the selectivity toward xylonic acid over other by-products.This work provides useful insights into the design of selective photocatalysts by engineering g-C_(3)N_(4)for biomass high-value utilization.
基金The work was mainly supported by the National Key Research and Development Program of China （no. 2017YFB1002101） and the National Natural Science Foundation of China （no. U1636203）.
文摘Hashtags of microblogs can provide valuable information for many natural language processing tasks. How to recommend reliable hashtags automatically has attracted considerable attention. However, existing studies assumed that all the training corpus crawled from social networks are labelled correctly, while large sample statistics on real social media shows that there are 8.9% of microblogs with hashtags having wrong labels. The notable influence of noisy data to the classifier is ignored before. Meanwhile, recency also plays an important role in microblog hashtag, but the information is not used in the existing studies. Some temporal hashtags such as World Cup will ignite at a particular time, but at other times, the number of people talking about it will sharply decrease. To address the twofold shortcomings above, the authors propose an long short-term memory-based model, which uses temporal enhanced selective sentence-level attention to reduce the influence of wrong labelled microblogs to the classifier. Experimental results using a dataset of 1.7 million microblogs collected from SINA Weibo microblogs demonstrated that the proposed method could achieve significantly better performance than the state-of-the-art methods.
基金CAMS Innovation Fund for Medical Sciences(CIFMS)(Nos.2022-I2M-1-013,2022-I2M-1-014,2022-I2M-2-002).
文摘The switchable cross-coupling of indoles and pyridotriazoles through carbene insertion at C_(2)-or C_(3)-positon has been developed in this paper.This highly site-selective C-H carbenoid functionalization is determined by both the Rh-catalyst species and auxiliary groups.[Cp∗RhCl_(2)]_(2) and coordinating pyrimidyl group direct the C-H carbenoid functionalization to occur at the C_(2)-position,while Rh2OAc4 and noncoordinating benzyl group lead the reaction to occur at the C_(3)-position of the indoles.This regioselective C−H functionalization strategy is of significant importance for the discovery of indole drugs.
基金supported by the National Natural Science Foundation of China(Nos.52273002 and 52333008)the funding of Boya Postdoctoral Fellowship at Peking University,BMS Junior Fellow Program and the National Funding Program for Postdoctoral Researchers(No.GZC20230031).
文摘A series of optically active copolymers with various feed ratios have been synthesized through helix-sense-selective copolymerization catalyzed by[Rh(norbornadiene)Cl]2-triethylamine.This process involves two proline-derived acetylene monomers,(S)-N-(4-chlorophenyl)carbamoyl-2-ethynyl pyrrolidine(MCl)and(S)-N-(tert-butoxycarbonyl)-2-ethynyl pyrrolidine,followed by acidic deprotection and neutralization.These copolymers adopt helical conformations with a preferred handedness,as demonstrated by nuclear magnetic resonance spectroscopy and a series of spectroscopic analyses.The chiroptical activity intensity of copolymer has been found to increase with MCl content.Consequently,the enantioseparation capabilities of copolymers containing 95 mol%,90 mol%,and 85 mol%MCl units have been assessed as chiral stationary phases in high-performance liquid chromatography because of their good chiroptical activities.These chiral stationary phases effectively enantioseparate racemic alcohols,sulfoxides,amides,and metal complexes.Notably,the copolymer with 90 mol%MCl shows superior chiral recognition ability,especially for 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanol(α=1.19)and 4-methylbenzenesulfinamide(α=1.47).Insights from molecular dynamic simulation and autodock analysis indicate that hydrogen bonding andπ-πstacking interactions between the chiral stationary phases and enantiomers play a key role for successful chiral separation.Our contribution not only demonstrates the importance of hydrogen bonding donor and copolymer chiroptical activity of chiral stationary phases for chiral resolution,but will also provide valuable insights for the future development of novel stationary phases.
基金financially supported by the Special Fund for Forestry Scientific Research in the Public Interest No.201504406the National Natural Science Foundation of China(Nos.31570705,31500362,31700553)+4 种基金the Shandong Provincial Natural Science Foundation,China(No.ZR2016CP01)the Project of Shandong Province Higher Educational Science and Technology Program(No.J16LF09)China Scholarship Council(No.201809135006)The contribution of S.de-Miguel was supported by the Spanish Ministry of Economy and Competitivity(MINECO)(Grant No.RTI2018–099315-A-I00)by a Serra-Húnter Fellowship provided by the Generalitat of Catalonia。
文摘Background:Robinia pseudoacacia is a widely planted pioneer tree species in reforestations on barren mountains in northern China.Because of its nitrogen-fixing ability,it can play a positive role in soil and forest restoration.After clearcutting of planted stands,R.pseudoacacia stands become coppice plantations.The impacts of shifting from seedling to coppice stands on soil bacterial community and soil properties have not been wel described.This study aims to quantify how soil properties and bacterial community composition vary between planted seedling versus coppice stands.Methods:Nine 20 m×20 m plots were randomly selected in seedling and coppice stands.The bulk soil and rhizosphere soil were sampled in summer 2017.Bulk soil was sampled at 10 cm from the soil surface using a soil auger.Rhizosphere soil samples were col ected using a brush.The soil samples were transported to the laboratory for chemical analysis,and bacterial community composition and diversity was obtained through DNA extraction,16 S r RNA gene amplification and high-throughput sequencing.Results:The results showed that,compared to seedling plantations,soil quality decreased significantly in coppice stands,but without affecting soil exchangeable Mg^(2+)and K^(+).Total carbon(C)and nitrogen(N)were lower in the rhizosphere than in bulk soil,whereas nutrient availability showed an opposite trend.The conversion from seedling to coppice plantations was also related to significant differences in soil bacterial community structure and to the reduction of soil bacterialα-diversity.Principal component analysis(PCA)showed that bacterial community composition was similar in both bulk and rhizosphere soils in second-generation coppice plantations.Special y,the conversion from seedling to coppice stands increased the relative abundance of Proteobacteria and Rhizobium,but reduced that of Actinobacteria,which may result in a decline of soil nutrient availability.Mantel tests revealed that C,N,soil organic matter(SOM),nitrate nitrogen(NO^(-)+(3)-N)and available phosphorus positively correlated with bacterial community composition,while a variation partition analysis(VPA)showed that NO^(-)+(3)-N explained a relatively greater proportion of bacterial distribution(15.12%),compared with C and SOM.Surprisingly,N showed no relationship with bacterial community composition,which may be related to nitrogen transportation.Conclusions:The conversion from seedling to coppice stands reduced soil quality and led to spatial-temporal homogenization of the soil bacterial community structure in both the rhizosphere and bulk soils.Such imbalance in microbial structure can accelerate the decline of R.pseudoacacia.This may affect the role of R.pseudoacacia coppice stands in soil and forest restoration of barren lands in mountain areas.
基金support from the Australian Research Council (LP160101521 and DP190100120)
文摘Electrochemistry has emerged as a major route for graphene and graphene oxide synthesis from graphite.Anodic graphite oxidation is commonly used with dilute mineral acid or aqueous salt electrolytes.In this system,the electrolyte acid concentration appears to be a critical parameter.However,the effect of the acid concentration,particularly at low concentrations,is still not fully understood.To address this issue,we used a packed bed electrochemical reactor to synthesize seven different electrochemical graphite oxide(EGO)products in 2–16M sulfuric acid.Detailed XRD,XPS,Raman,conductivity and optical microscopy analysis of the products was carried out.We found dilute acid(<10 M)graphite oxides were less crystalline and less oxidized than those produced in stronger acids.The oxygen evolution reaction at the graphite surface appears to affect the structural changes,oxidation mechanism,and electrochemical corrosion of the anode.EGO conductivity is also strongly affected by the electrolyte’s acidity.We show that well oxidized,yet reasonably conductive,single layer graphene oxide can be produced from 7.1M acid.These results broaden our understanding of graphite electrochemistry and will serve to inform future electrochemical graphene synthesis efforts.
基金supported by the Outstanding Youth Team Project of Guangdong Natural Science Foundation(2023B1515040013)Guangdong Basic and Applied Basic Research Foundation(2023A1515012215,2023B1515040013,2023A1515012519)+1 种基金State Key Laboratory of Pulp&Paper Engineering(2023C07,2023PY03)Guangdong Col ege Students’Scientific and Technological Innovation(“Climbing Program”Special Fund,Pdjh2022a0026)
文摘The separator is an essential component of sodium-ion batteries(SIBs)to determine their electrochemical performances.However,the separator with high mechanical strength,good electrolyte wettability and excellent electrochemical performance remains an open challenge.Herein,a new separator consisting of amphoteric nanofibers with abundant functional groups was fabricated through supramolecular assembly of natural polymers for SIB.The uniform nanoporous structure,remarkable mechanical properties and abundant functional groups(e.g.-COOH,-NH_(2)and-OH)endow the separator with lower dissolution activation energy and higher ion migration numbers.These metrics enable the separator to lower the barrier for desolvation of Na^(+),accelerate the migration of Na^(+),and generate more stable solid electrolyte interphase(SEI)and cathode electrolyte interphase(CEI).The battery assembled with the amphoteric nanofiber separator shows higher specific capacity and better stability than that assembled with glass fiber(GF)separator.
基金The financial support from the National Natural Science Foundation of China(Grant No.51973201,U1804128,to X.P.Grant No.52173209,to Y.H.)+4 种基金the 111 Project(D18023,to X.P.)the National Science Foundation for Young Scientists of China(Grant No.22105179,to G.S.)the National Key R&D Program of China(2017YFB0307600,to M.L)China Postdoctoral Science Foundation(2020M682317,to X.Z)Scientific&technological research projects in Henan Province(222102520009,to X.Q.)
文摘Liquid metal(LM)and liquid metal alloys(LMs)possess unique physicochemical features,which have become emerging and functionalized materials that are attractive applicants in various fields.Herein,uniform LM nanodroplets armored by carbon dots(LMD@CDs)were prepared and exhibited high colloidal stability in various solvents,as well as water.After optimization,LMD@CDs can be applied as functional additives for the 3D/4D printing of hydrogel and cross-linked resin through digital light processing(DLP).The light absorption of LMD@CDs not only improved the printing accuracy,but also led to the cross-linking density differential during the post-curing process.Base on the cross-linking density differential of soft hydrogel and photothermal performance of the LM,the 3D printed objects can exhibit stimulus responses to both water and laser irradiation.Additionally,the CDs shell and LM core of LMD@CDs provide the printed objects interesting photoluminescence and electric conductivity capabilities,respectively.We deduce this versatile 3D/4D printing system would provide a new platform for the preparation of multi-functional and stimuli-responsive advance materials.
基金We thank the other members of Plant Quarantine and Invasion Biology Laboratory,China Agricultural University(CAUPQL)who helped us during this study.The research was supported by the National Natural Science Foundation Project of China(31801802)Fundamental Research Funds for the Central Universities,China(2019 TC060).
文摘Fruit flies usually harbor diverse communities of bacteria in their digestive systems,which are known to play a significant role in their fitness.However,little information is available on Zeugodacus tau,a polyphagous pest worldwide.This study reports the first extensive analysis of bacterial communities in different life stages and their effect on the development and reproduction of laboratory-reared Z tan.Cultured bacteria were identified using the conventional method and all bacteria were identified by highthroughput technologies(16S ribosomal RNA gene sequencing of V3-V4 region).A total of six bacterial phyla were identified in larvae,pupae,and male and female adult flies,which were distributed into 14 classes,32 orders,58 families and 96 genera.Proteobacteria was the most represented phylum in all the stages except larvae.Enterobacter,Klebsiella,Providencia,and Pseudomonas were identified by conventional and next-generation sequencing analysis in both male and female adult flies,and Enterobacter was found to be the main genus.After being fed with antibiotics from the first instar larvae,bacterial diversity changed markedly in the adult stage.Untreated flies laid eggs and needed 20 days before oviposition while the treated flies showed ovary development inhibited and were not able to lay eggs,probably due to the alteration of the microbiota.These findings provide the cornerstone for unexplored research on bacterial function in Z tau,which will help to develop an environmentally friendly management technique for this kind of harmful insect.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.62106010,61976010,62176011,62236010.
文摘Image emotion classification(IEC)aims to extract the abstract emotions evoked in images.Recently,language-supervised methods such as con-trastive language-image pretraining(CLIP)have demonstrated superior performance in image under-standing.However,the underexplored task of IEC presents three major challenges:a tremendous training objective gap between pretraining and IEC,shared suboptimal prompts,and invariant prompts for all instances.In this study,we propose a general framework that effectively exploits the language-supervised CLIP method for the IEC task.First,a prompt-tuning method that mimics the pretraining objective of CLIP is introduced,to exploit the rich image and text semantics associated with CLIP.Subsequently,instance-specific prompts are automatically composed,conditioning them on the categories and image content of instances,diversifying the prompts,and thus avoiding suboptimal problems.Evaluations on six widely used affective datasets show that the proposed method significantly outperforms state-of-the-art methods(up to 9.29%accuracy gain on the EmotionROI dataset)on IEC tasks with only a few trained parameters.The code is publicly available at https://github.com/dsn0w/PT-DPC/for research purposes.
基金This study was supported by the Young Beijing Scholars Program and Beijing Agricultural Forestry Academy Foundation(QNJJ202218).
文摘This study established back-propagation neural networks(BPNNs)for evaluating the freshness of bighead carp(Hypophthalmichthys nobilis)heads during chilled storage via fluorescence spectroscopy using an excitation-emission matrix(EEM).The total volatile basic nitrogen(TVB-N)and total aerobic count(TAC)of fish increased obviously during storage at 0,4,8,12,and 16°C,while sensory scores decreased with increasing storage time.The EEM fluorescence intensity was measured,and its change was correlated with the freshness indicators of the samples.Three characteristic components of EEM data were extracted by parallel factor analysis,and two freshness indicators were used to construct the EEM-BPNNs model.The results demonstrated that the relative errors of the EEM-BPNNs model for TVB-N and TAC were less than 14%.This result indicated that the EEM-BPNNs model could determine the freshness of fish in cold chains in a rapid and nondestructive way.
基金supported by the National Key Research and Development Program of China(2022YFB4601402)the National Natural Science Foundation of China(32201109,51772233,82072446)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2022B1515120052,2021A1515110557)the Key Basic Research Program of Shenzhen(JCYJ20200109150218836)the Chaozhou Branch of Chemistry and Chemical Engineering Guangdong Laboratory(HJL202202A002)the Trauma Microsurgery Clinical Medical Research Center of Hubei Province and the Health Commission of Hubei Province Medical Leading Talent Project(LJ20200405).
文摘Diabetic wounds are a difficult medical challenge.Excessive secretion of matrix metalloproteinase-9(MMP-9)in diabetic wounds further degrades the extracellular matrix and growth factors and causes severe vascular damage,which seriously hinders diabetic wound healing.To solve these issues,a double-network porous hydrogel composed of poly(methyl methacrylate-co-acrylamide)(p(MMA-co-AM))and polyvinyl alcohol(PVA)was constructed by the high internal phase emulsion(HIPE)technique for the delivery of potassium sucrose octasulfate(PSO),a drug that can inhibit MMPs,increase angiogenesis and improve microcirculation.The hydrogel possessed a typical polyHIPE hierarchical microstructure with interconnected porous morphologies,high porosity,high specific surface area,excellent mechanical properties and suitable swelling properties.Meanwhile,the p(MMA-co-AM)/PVA@PSO hydrogel showed high drug-loading performance and effective PSO release.In addition,both in vitro and in vivo studies showed that the p(MMA-co-AM)/PVA@PSO hydrogel had good biocompatibility and significantly accelerated diabetic wound healing by inhibiting excessive MMP-9 in diabetic wounds,increasing growth factor secretion,improving vascularization,increasing collagen deposition and promoting re-epithelialization.Therefore,this study provided a reliable therapeutic strategy for diabetic wound healing,some theoretical basis and new insights for the rational design and preparation of wound hydrogel dressings with high porosity,high drug-loading performance and excellent mechanical properties.
基金funded by the 2024 Philosophy and Social Science Research in Colleges and Universities Program in Jiangsu Province(Grant No.2024SJYB0167)the 2023 Nanjing Tech University Talent Introduction and Development Program(Grant No.YPJH2023-03)the research project of Observation Research Station of Land Ecology and Land Use in the Yangtze River Delta,Ministry of Natural Resources(Grant No.2023YRDLELU05).
文摘The urban spatial structure reflects a city’s development history,cultural heritage,and socio-economic conditions.A rational urban spatial structure is crucial for urban development.This study focuses on the main urban area of Nanjing,analyzing POI and nighttime light data from 2016 to 2020.Utilizing kernel density estimation and coupling coordination models,it explores the temporal and spatial evolution characteristics of Nanjing’s urban spatial structure.Geographic detectors are employed to assess the impact of various factors on this structure.The findings indicate that:(1)Nanjing’s urban spatial structure displays a pattern of central aggregation and peripheral expansion,with high brightness concentrated in the urban center and a significant increase in peripheral brightness,signaling initial success in establishing urban subcenters;(2)The coupling relationship between nighttime light brightness and POI density has strengthened,suggesting improved coordination of the urban spatial structure;(3)The evolution of Nanjing’s urban spatial structure results from the combined effects of multiple factors,including economic level,population distribution,transportation conditions,and policy planning.
基金supported by the the National Natural This study was financially supported by the National Youth Top‐notch Talent Support Program,the State Key Laboratory of Pulp and Paper Engineering Funds(2020C03)the National Natural Science Foundation of China(31971614,32071714,21736003,and 52003083)+2 种基金Guangzhou Science and Technology Funds(201904010078 and 202002030167)the China Postdoctoral Science Foundation funded project(2019T120725,2019M652882,2019M662924,2020M682711,and 2020M682710)Guangdong Basic and Applied Basic Research Foundation(2020A1515110705)。
文摘With the rapid development of wearable and intelligent flexible electronic devices(FEDs),the demand for flexible energy storage/conversion devices(ESCDs)has also increased.Rechargeable flexible metal‐air batteries(MABs)are expected to be one of the most ideal ESCDs due to their high theoretical energy density,cost advantage,and strong deformation adaptability.With the improvement of the device design,material assemblies,and manufacturing technology,the research on the electrochemical performance of flexible MABs has made significant progress.However,achieving the high mechanical flexibility,high safety,and wearable comfortability required by FEDs while maintaining the high performance of flexible MABs are still a daunting challenge.In this review,flexible Zn‐air and Li‐air batteries are mainly exemplified to describe the most recent progress and challenges of flexible MABs.We start with an overview of the structure and configuration of the flexible MABs and discuss their impact on battery performance and function.Then it focuses on the research progress of flexible metal anodes,gel polymer electrolytes,and air cathodes.Finally,the main challenges and future research perspectives involving flexible MABs for FEDs are proposed.
