This paper addresses the consensus problem of nonlinear multi-agent systems subject to external disturbances and uncertainties under denial-ofservice(DoS)attacks.Firstly,an observer-based state feedback control method...This paper addresses the consensus problem of nonlinear multi-agent systems subject to external disturbances and uncertainties under denial-ofservice(DoS)attacks.Firstly,an observer-based state feedback control method is employed to achieve secure control by estimating the system's state in real time.Secondly,by combining a memory-based adaptive eventtriggered mechanism with neural networks,the paper aims to approximate the nonlinear terms in the networked system and efficiently conserve system resources.Finally,based on a two-degree-of-freedom model of a vehicle affected by crosswinds,this paper constructs a multi-unmanned ground vehicle(Multi-UGV)system to validate the effectiveness of the proposed method.Simulation results show that the proposed control strategy can effectively handle external disturbances such as crosswinds in practical applications,ensuring the stability and reliable operation of the Multi-UGV system.展开更多
The phenomenon of fear memory generalization can be defined as the expansion of an individual's originally specific fear responses to a similar yet genuinely harmless stimulus or situation subsequent to the occurr...The phenomenon of fear memory generalization can be defined as the expansion of an individual's originally specific fear responses to a similar yet genuinely harmless stimulus or situation subsequent to the occurrence of a traumatic event[1].Fear generalization within the normal range represents an adaptive evolutionary mechanism to facilitate prompt reactions to potential threats and to enhance the likelihood of survival.展开更多
Long-term niche differentiation will lead to the evolution of diverse adaptive strategies for species in diverse environments. The present study selected two Forsythia species, Forsythia mandshurica(Fm)-which naturall...Long-term niche differentiation will lead to the evolution of diverse adaptive strategies for species in diverse environments. The present study selected two Forsythia species, Forsythia mandshurica(Fm)-which naturally occurs in a cold temperate zone and Forsythia suspensa(Fs)-which thrives in a warm temperate zone-to reveal their differential chilling defense mechanisms by integrating morpho-physiological,transcriptomic, and metabolomic data. Transcriptome results show that Fm has evolved in a series of adaptive mechanisms designed to help the plants to cope with chilling stress by enhancing sugar, amino acid, hormone, polyamine, and phenol content to improve cell osmotic potential and to mitigate petal browning. Metabolomic data suggested the increased chilling resistance of Fm relies on in the plant being rich in a-linolenic acid, linoleic acid, as well as two amino acids, Phe and Trp, and has low levels of cinnamic acid and gramine in flowers compared to Fs. A higher abundance of glutathione disulfide and NADPH regulated by glutathione peroxidases and NADPH improved the ability of the cellular antioxidant and reduction-oxidation system stability in Fm;Additionally, the elevated levels of pyruvate, a-ketoglutaric acid, and oxaloacetic acid in Fm contributed to a significantly enhanced ATP production in mitochondria. Through Ka/Ks and gene expression analysis,four transcription factors, EVM0025036(bHLH), EVM0010639 and EVM0007275(AP2), and EVM0025908(bZIP) were identified that may contribute to the high cold tolerance of Fm. These adaptations highlight the intricate interplay between genetic and physiological processes that shape the survival strategies of plants in response to their specific ecological niches.展开更多
The Polar Regions host one of the harshest and most unique ecosystems on Earth,harboring a diverse array of micro-and macro-organisms.These inhabitants showcase remarkable taxonomic and genetic originality,presenting ...The Polar Regions host one of the harshest and most unique ecosystems on Earth,harboring a diverse array of micro-and macro-organisms.These inhabitants showcase remarkable taxonomic and genetic originality,presenting unparalleled opportunities for bioprospecting,alongside demonstrating extraordinary adaptation mechanisms for survival.Furthermore,polar organisms play crucial roles in facilitating organic matter decomposition,carbon fixation and sequestration,and biogeochemical cycling.Moreover,these organisms serve as pivotal indicators of global climate shifts.Therefore,exploring the polar organisms and ecosystem holds profound and significant implications for gaining deeper insights into scientific frontiers such as global biodiversity,elementary cycling,climate change,resource utilization,and the awe of life in extreme environments.展开更多
This paper explores the issue of secure synchronization control in piecewise-homogeneous Markovian jump delay neural networks affected by denial-of-service(DoS)attacks.Initially,a novel memory-based adaptive event-tri...This paper explores the issue of secure synchronization control in piecewise-homogeneous Markovian jump delay neural networks affected by denial-of-service(DoS)attacks.Initially,a novel memory-based adaptive event-triggered mechanism(MBAETM)is designed based on sequential growth rates,focusing on event-triggered conditions and thresholds.Subsequently,from the perspective of defenders,non-periodic DoS attacks are re-characterized,and a model of irregular DoS attacks with cyclic fluctuations within time series is further introduced to enhance the system's defense capabilities more effectively.Additionally,considering the unified demands of network security and communication efficiency,a resilient memory-based adaptive event-triggered mechanism(RMBAETM)is proposed.A unified Lyapunov-Krasovskii functional is then constructed,incorporating a loop functional to thoroughly consider information at trigger moments.The master-slave system achieves synchronization through the application of linear matrix inequality techniques.Finally,the proposed methods'effectiveness and superiority are confirmed through four numerical simulation examples.展开更多
The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activa...The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activated sludge(WAS)on the generation of volatile fatty acids(VFAs)during anaerobic fermentation.The low level of PHMG(100 mg/g TSS)significantly promoted the VFAs generation(1283 mg COD/L,compared with 337 mg COD/L in the control)via synchronously facilitating the solubilization,hydrolysis,and acidification steps but inhibiting methanogenesis.Metagenomic analysis showed that the functional anaerobe(i.e.,Bacteroides,Macellibacteroide and Parabacteroide)and corresponding genetic expressions responsible for extracellular hydrolysis(i.e.,clp P),membrane transport(i.e.,ffh and gsp F),intracellular substrates metabolism(i.e.,ald and paa F)and VFAs biosynthesis(i.e.,ACACA and FASN)were enhanced in the optimal presence of PHMG.Moreover,the anaerobic species could respond and adapt to low PHMG stimuli via quorum sensing(i.e.,cqs A,rpf C and rpf G),and thus maintain the high microbial metabolic activities.However,they were unable to tolerate the toxicity of excessive PHMG,resulting in the extremely low VFAs production.This work enlightened the effects of emerging pollutants on WAS fermentation at the genetic levels,and provided guidance on the WAS treatment and resource recovery.展开更多
Intestinal microbes are closely related to vital host functions such as digestion and nutrient absorption,which play important roles in enhancing host adaptability.As a natural“laboratory”,caves provide an outstandi...Intestinal microbes are closely related to vital host functions such as digestion and nutrient absorption,which play important roles in enhancing host adaptability.As a natural“laboratory”,caves provide an outstanding model for understanding the significance of gut microbes and feeding habits in the habitat adaptability of hosts.However,research on the relationship between gut microbes,feeding habits,and the adaptability of troglobites remains insufficient.In this study,we compared the characteristics of the intestinal microbes of Sinocyclocheilus cavefish and surface fish and further established the relationship between intestinal and habitat microbes.Furthermore,we conducted environmental DNA(eDNA)(metabarcoding)analysis of environmental samples to clarify the composition of potential food resources in the habitats of the Sinocyclocheilus cavefish and surface fish.Results showed that the structure of the Sinocyclocheilus gut microbes was more related to ecological type(habitat type)than phylogenetic relationships.While horizontal transfer of habitat microbes was a source of gut microbes,hosts also showed strong selection for inherent microbes as dominant microorganisms.Differences in the composition and structure of gut microbes,especially dominant microbes,may enhance the adaptability of the two Sinocyclocheilus fish types from the perspectives of food intake,nutrient utilization,and harmful substance metabolism,suggesting that food resources,predation patterns,intestinal flora,digestive and absorptive capacity,and feeding habits and preferences are linked to habitat adaptability.These results should facilitate our understanding of the significance of fish gut microbes to habitat adaptation and provide a new perspective for studying the adaptive mechanisms of cavefish.展开更多
Mechanical adaptation of tissue engineering scaffolds is critically important since natural tissue regeneration is highly regulated by mechanical signals.Herein,we report a facile and convenient strategy to tune the m...Mechanical adaptation of tissue engineering scaffolds is critically important since natural tissue regeneration is highly regulated by mechanical signals.Herein,we report a facile and convenient strategy to tune the modulus of waterborne biodegradable polyurethanes(WBPU)via cross-linking manipulation of phase separation and water infiltration for constructing mechanically adaptable tissue engineering scaffolds.Amorphous aliphatic polycarbonate and trifunctional trimethylolpropane were introduced to polycaprolactone-based WBPUs to interrupt interchain hydrogen bonds in the polymer segments and suppress microphase separation,inhibiting the crystallization process and enhancing covalent cross-linking.Intriguingly,as the crosslinking density of WBPU increases and the extent of microphase separation decreases,the material exhibits a surprisingly soft modulus and enhanced water infiltration.Based on this strategy,we constructed WBPU scaffolds with a tunable modulus to adapt various cells for tissue regeneration and regulate the immune response.As a representative application of brain tissue regeneration model in vivo,it was demonstrated that the mechanically adaptable WBPU scaffolds can guide the migration and differentiation of endogenous neural progenitor cells into mature neurons and neuronal neurites and regulate immunostimulation with low inflammation.Therefore,the proposed strategy of tuning the modulus of WBPU can inspire the development of novel mechanically adaptable biomaterials,which has very broad application value.展开更多
In recent years, cyber attacks have posed great challenges to the development of cyber-physical systems. It is of great significance to study secure state estimation methods to ensure the safe and stable operation of ...In recent years, cyber attacks have posed great challenges to the development of cyber-physical systems. It is of great significance to study secure state estimation methods to ensure the safe and stable operation of the system. This paper proposes a secure state estimation for multi-input and multi-output continuous-time linear cyber-physical systems with sparse actuator and sensor attacks. First, for sparse sensor attacks, we propose an adaptive switching mechanism to mitigate the impact of sparse sensor attacks by filtering out their attack modes. Second, an unknown input sliding mode observer is designed to not only observe the system states, sensor attack signals, and measurement noise present in the system but also counteract the effects of sparse actuator attacks through an unknown input matrix. Finally, for the design of an unknown input sliding mode state observer, the feasibility of the observing system is demonstrated by means of Lyapunov functions. Additionally, simulation experiments are conducted to show the effectiveness of this method.展开更多
Nucleus pulposus(NP)tissue engineering brings new hope in the repair of intervertebral disc degeneration(IVDD).IVDD is often accompanied by multiscale changes in the mechanical microenvironment,including the changes o...Nucleus pulposus(NP)tissue engineering brings new hope in the repair of intervertebral disc degeneration(IVDD).IVDD is often accompanied by multiscale changes in the mechanical microenvironment,including the changes of mechanical property of collagen fibril,NP tissue,and mechanical instability of spine.In this study,a multiscale mechanically-adapted strategy is proposed to promote NP repair.To achieve this goal,a viscoelasticadapted dual-network hydrogel(PVA-DN)is constructed.The hydrogel with multiscale tunable viscoelasticity and dynamic compression condition is used to meet the multiscale mechanical requirements of NP regeneration.The results show that the viscoelastic hydrogel promotes the proliferation,migration and adhesion of nucleus pulposus cell(NPC)as well as the secretion of NP-specific extracellular matrix.RNA-seq results show that it attenuates the inflammatory microenvironment by inhibiting the IL-17 signaling pathway.Appropriate dynamic compression applied to the viscoelastic scaffold further promotes the physiological function of NPC,and the viscoelasticity of hydrogel protects against NPC damage induced by excessive compression.Animal experiments demonstrate that the viscoelastic hydrogel effectively restores disc mechanical function and delays disc degen-eration in rats.Findings from this study highlight that the multiscale mechanically-adapted strategy is effective in the repair of IVDD.展开更多
Saussurea medusa,Saussurea hypsipeta and Saussurea obvallata are typical alpine snowline plants growing in the Qinghai-Tibet plateau.They are characterized by a specialized morphology.S.medusa and S.hypsipeta have ver...Saussurea medusa,Saussurea hypsipeta and Saussurea obvallata are typical alpine snowline plants growing in the Qinghai-Tibet plateau.They are characterized by a specialized morphology.S.medusa and S.hypsipeta have very dense trichomes on whole plant,whereas S.obvallata has transparent bracts covered inflorescences.The different forms reflect their adaptation to cold environments.To investigate the different mechanisms of adaptation of these species to cold temperatures,transcriptome sequencing was performed in three species of Saussurea DC.A total of 116394137237 and 113879 Unigenes were identified from S.medusa,S.hypsipeta and S.obvallata,respectively.Of these,55909(48.03%),65519(47.74%)and 51889(45.56%)Unigenes were matched in public databases.GO analysis identified that most of annotated Unigenes in the three species of plants were related to cellular,metabolic,and single−organism processes,and binding and catalytic activities.The differential expression of 37 genes related to environmental adaptation were discovered by pairwise comparisons.Of these,two candidate genes(Interaptin-like and CSLB3)related to trichome development were identified only in S.medusa and S.hypsipeta,which was consistent with their distinct morphology.Our data can provide a valuable resource for the further studies on the adaptive mechanisms of molecular and functional ecology in Saussurea DC.展开更多
A recent study published in Cell Metabolism entitled“Gut microbial alterations in arginine metabolism determine bone mechanical adaptation”demonstrated that administration of L-arginine enhanced bone mechanical adap...A recent study published in Cell Metabolism entitled“Gut microbial alterations in arginine metabolism determine bone mechanical adaptation”demonstrated that administration of L-arginine enhanced bone mechanical adaptation by activating a nitric oxide-calcium feedback loop in osteocytes.The findings revealed that mechanical regulation of bone adaptation is associated with gut microbiota.The underlying cause of heterogeneity of bone mechanoresponsiveness was the significant difference in the composition of the gut microbiota,in which the family Lachnospiraceae contributed to the inter-individual high variability in bone mechanical adaptation.Additionally,administration of Lachnospiraceae exhibited increased expression levels of L-citrulline and L-arginine and enhanced bone mechanoresponsiveness in recipients.Collectively,this study provides mechanistic insights into inter-individual variability of the gut microbial,which is related to the heterogeneity of bone mechanical adaptation and provides a novel preventive and therapeutic strategy to anti-osteoporotic for maximizing bone mechanoresponsiveness via the microbiota-metabolite axis.展开更多
In this paper, an approach to the control of continuous-time chaotic systems is proposed using the Takagi-Sugeno （TS） fuzzy model and adaptive adjustment. Sufficient conditions are derived to guarantee chaos control...In this paper, an approach to the control of continuous-time chaotic systems is proposed using the Takagi-Sugeno （TS） fuzzy model and adaptive adjustment. Sufficient conditions are derived to guarantee chaos control from Lyapunov stability theory. The proposed approach offers a systematic design procedure for stabilizing a large class of chaotic systems in the literature about chaos research. The simulation results on Rossler＇s system verify the effectiveness of the proposed methods.展开更多
This paper investigates the event-triggered security consensus problem for nonlinear multi-agent systems(MASs)under denial-of-service(Do S)attacks over an undirected graph.A novel adaptive memory observer-based anti-d...This paper investigates the event-triggered security consensus problem for nonlinear multi-agent systems(MASs)under denial-of-service(Do S)attacks over an undirected graph.A novel adaptive memory observer-based anti-disturbance control scheme is presented to improve the observer accuracy by adding a buffer for the system output measurements.Meanwhile,this control scheme can also provide more reasonable control signals when Do S attacks occur.To save network resources,an adaptive memory event-triggered mechanism(AMETM)is also proposed and Zeno behavior is excluded.It is worth mentioning that the AMETM's updates do not require global information.Then,the observer and controller gains are obtained by using the linear matrix inequality(LMI)technique.Finally,simulation examples show the effectiveness of the proposed control scheme.展开更多
Antarctic ice microalga Chlamydomonas sp. can thrive undisturbed under high UV radiation in the Antarctic ice layer. However, it is unknown that the initial adaptation mechanisms in protein level occurring in response...Antarctic ice microalga Chlamydomonas sp. can thrive undisturbed under high UV radiation in the Antarctic ice layer. However, it is unknown that the initial adaptation mechanisms in protein level occurring in response to high UV radiation. Global-expression profiling of proteins in response to stress was analyzed by two-dimensional electrophoresis （2-DE） and image analysis. In the 2-DE analysis, protein preparation is the key step. Three different protein extract methods were compared, and the results showed that the trichloroacetic acid （TCA）-acetone fractional precipitation method was the fittest one. At the same time, the proteins in Chlamydomonas sp. were compared in 2-DE way, and the synthesis of seven protein spots was found disappeared and 18 decreased after exposed to UV-B radiation. In addition, 14 protein spots were enhanced or induced, among which two new peptides （20 and 21 kDa） appeared whose isoelectric point （pI） was 7.05 and 4.60 respectively. These changed proteins might act as key role in the acclimation of Antarctic ice microalga to UV-B radiation展开更多
Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbi...Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbine(MCT)system,the nonlinear controllers which rely on precise mathematical models show poor performance under a high level of parameters’uncertainties.This paper proposes an adaptive single neural control(ASNC)strategy for variable step-size perturb and observe(P&O)maximum power point tracking(MPPT)control.Firstly,to automatically update the neuron weights of SNC for the nonlinear systems,an adaptive mechanism is proposed to adaptively adjust the weighting and learning coefficients.Secondly,aiming to generate the exact reference speed for ASNC to extract the maximum power,a variable step-size law based on speed increment is designed to strike a balance between tracking speed and accuracy of P&O MPPT.The robust stability of the MCT control system is guaranteed by the Lyapunov theorem.Comparative simulation results show that this strategy has favorable adaptive performance under variable velocity conditions,and the MCT system operates at maximum power point steadily.展开更多
In this paper,a non-negative adaptive mechanism based on an adaptive nonsingular fast terminal sliding mode control strategy is proposed to have finite time and high-speed trajectory tracking for parallel manipulators...In this paper,a non-negative adaptive mechanism based on an adaptive nonsingular fast terminal sliding mode control strategy is proposed to have finite time and high-speed trajectory tracking for parallel manipulators with the existence of unknown bounded complex uncertainties and external disturbances.The proposed approach is a hybrid scheme of the online non-negative adaptive mechanism,tracking differentiator,and nonsingular fast terminal sliding mode control(NFTSMC).Based on the online non-negative adaptive mechanism,the proposed control can remove the assumption that the uncertainties and disturbances must be bounded for the NFTSMC controllers.The proposed controller has several advantages such as simple structure,easy implementation,rapid response,chattering-free,high precision,robustness,singularity avoidance,and finite-time convergence.Since all control parameters are online updated via tracking differentiator and non-negative adaptive law,the tracking control performance at high-speed motions can be better in real-time requirement and disturbance rejection ability.Finally,simulation results validate the effectiveness of the proposed method.展开更多
Molecular mechanisms of plant responses to salinity stress and the physiological consequences of altered gene expression are reviewed. Extensive use of comparisons with halophytic plants and glycophytos provide a para...Molecular mechanisms of plant responses to salinity stress and the physiological consequences of altered gene expression are reviewed. Extensive use of comparisons with halophytic plants and glycophytos provide a paradigm for many responses to salinity exhibited by stress sensitive plants. Osmolyte biosynthesis, water flux control, and membrane transport of ions are important for maintenance and re-establishment of homeostasis. Transgenic plant and mutant analyses in Arabidopsis improve the understanding of stress responses and elements of stress signal transduction pathways. The genomic DNA sequences and cell-specific transcript expression data, combined with determinant identification based on molecular genetics, will provide the infrastructure for functional physiological dissection of salt tolerance determinants in plants. Protein interaction analysis, genetic activation and suppression screens will lead inevitably to an understanding of the interrelationships of the multiple signaling systems that control stress-adaptive responses and provide more opportunity to engineer salt tolerance in plants.展开更多
Erigeron annuus(L.)Pers.,an alien species,is widely distributed in most areas of China.It was included in the third batch of invasive alien species list by the Ministry of Ecology and Environment of China,and it is a ...Erigeron annuus(L.)Pers.,an alien species,is widely distributed in most areas of China.It was included in the third batch of invasive alien species list by the Ministry of Ecology and Environment of China,and it is a first-level malignant invasive plant.Due to its great reproducibility with a mass of seeds,power adaptability to the external environment and strong allelopathy,it has highly invasive and adaptability,and has affected the development of the agriculture and forestry,the diversity of local species and the ecosystem.In this paper,we summarized the current invasion situation,invasion and adaptation mechanism of E.annuus,and prospected further research on E.annuus invasion mechanism,hoping to provide a reference for realizing its effective management.展开更多
For exchanging and sharing information and services in e-government, a framework of information service platform (ISP) is presented. The multi-layer architecture of the ISP is introduced. They are. user's requirem...For exchanging and sharing information and services in e-government, a framework of information service platform (ISP) is presented. The multi-layer architecture of the ISP is introduced. They are. user's requirement layer, business service layer, business process layer, business function layer and data layer. The lower layers are based on the architecture of web services and the upper layers are related to the institutional and organizational issues. In order to deal with the variation of user's requirements and changing environment, the matching and mapping processes with adaptive mechanism are illustrated.展开更多
基金The National Natural Science Foundation of China(W2431048)The Science and Technology Research Program of Chongqing Municipal Education Commission,China(KJZDK202300807)The Chongqing Natural Science Foundation,China(CSTB2024NSCQQCXMX0052).
文摘This paper addresses the consensus problem of nonlinear multi-agent systems subject to external disturbances and uncertainties under denial-ofservice(DoS)attacks.Firstly,an observer-based state feedback control method is employed to achieve secure control by estimating the system's state in real time.Secondly,by combining a memory-based adaptive eventtriggered mechanism with neural networks,the paper aims to approximate the nonlinear terms in the networked system and efficiently conserve system resources.Finally,based on a two-degree-of-freedom model of a vehicle affected by crosswinds,this paper constructs a multi-unmanned ground vehicle(Multi-UGV)system to validate the effectiveness of the proposed method.Simulation results show that the proposed control strategy can effectively handle external disturbances such as crosswinds in practical applications,ensuring the stability and reliable operation of the Multi-UGV system.
基金supported by the Shandong Provincial Natural Science Foundation(ZR2022QH144).
文摘The phenomenon of fear memory generalization can be defined as the expansion of an individual's originally specific fear responses to a similar yet genuinely harmless stimulus or situation subsequent to the occurrence of a traumatic event[1].Fear generalization within the normal range represents an adaptive evolutionary mechanism to facilitate prompt reactions to potential threats and to enhance the likelihood of survival.
基金supported by the National Natural Science Foundation of China(Grant NO.32360307).
文摘Long-term niche differentiation will lead to the evolution of diverse adaptive strategies for species in diverse environments. The present study selected two Forsythia species, Forsythia mandshurica(Fm)-which naturally occurs in a cold temperate zone and Forsythia suspensa(Fs)-which thrives in a warm temperate zone-to reveal their differential chilling defense mechanisms by integrating morpho-physiological,transcriptomic, and metabolomic data. Transcriptome results show that Fm has evolved in a series of adaptive mechanisms designed to help the plants to cope with chilling stress by enhancing sugar, amino acid, hormone, polyamine, and phenol content to improve cell osmotic potential and to mitigate petal browning. Metabolomic data suggested the increased chilling resistance of Fm relies on in the plant being rich in a-linolenic acid, linoleic acid, as well as two amino acids, Phe and Trp, and has low levels of cinnamic acid and gramine in flowers compared to Fs. A higher abundance of glutathione disulfide and NADPH regulated by glutathione peroxidases and NADPH improved the ability of the cellular antioxidant and reduction-oxidation system stability in Fm;Additionally, the elevated levels of pyruvate, a-ketoglutaric acid, and oxaloacetic acid in Fm contributed to a significantly enhanced ATP production in mitochondria. Through Ka/Ks and gene expression analysis,four transcription factors, EVM0025036(bHLH), EVM0010639 and EVM0007275(AP2), and EVM0025908(bZIP) were identified that may contribute to the high cold tolerance of Fm. These adaptations highlight the intricate interplay between genetic and physiological processes that shape the survival strategies of plants in response to their specific ecological niches.
文摘The Polar Regions host one of the harshest and most unique ecosystems on Earth,harboring a diverse array of micro-and macro-organisms.These inhabitants showcase remarkable taxonomic and genetic originality,presenting unparalleled opportunities for bioprospecting,alongside demonstrating extraordinary adaptation mechanisms for survival.Furthermore,polar organisms play crucial roles in facilitating organic matter decomposition,carbon fixation and sequestration,and biogeochemical cycling.Moreover,these organisms serve as pivotal indicators of global climate shifts.Therefore,exploring the polar organisms and ecosystem holds profound and significant implications for gaining deeper insights into scientific frontiers such as global biodiversity,elementary cycling,climate change,resource utilization,and the awe of life in extreme environments.
文摘This paper explores the issue of secure synchronization control in piecewise-homogeneous Markovian jump delay neural networks affected by denial-of-service(DoS)attacks.Initially,a novel memory-based adaptive event-triggered mechanism(MBAETM)is designed based on sequential growth rates,focusing on event-triggered conditions and thresholds.Subsequently,from the perspective of defenders,non-periodic DoS attacks are re-characterized,and a model of irregular DoS attacks with cyclic fluctuations within time series is further introduced to enhance the system's defense capabilities more effectively.Additionally,considering the unified demands of network security and communication efficiency,a resilient memory-based adaptive event-triggered mechanism(RMBAETM)is proposed.A unified Lyapunov-Krasovskii functional is then constructed,incorporating a loop functional to thoroughly consider information at trigger moments.The master-slave system achieves synchronization through the application of linear matrix inequality techniques.Finally,the proposed methods'effectiveness and superiority are confirmed through four numerical simulation examples.
基金financially supported by the National Natural Science Foundation of China(No.52070069)Jiangsu Province Natural Science Foundation(No.BK20211207)+3 种基金China Postdoctoral Science Foundation(No.2021M692423)Shanghai Post-doctoral Excellence Program(No.2020419)State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF20005)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China。
文摘The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activated sludge(WAS)on the generation of volatile fatty acids(VFAs)during anaerobic fermentation.The low level of PHMG(100 mg/g TSS)significantly promoted the VFAs generation(1283 mg COD/L,compared with 337 mg COD/L in the control)via synchronously facilitating the solubilization,hydrolysis,and acidification steps but inhibiting methanogenesis.Metagenomic analysis showed that the functional anaerobe(i.e.,Bacteroides,Macellibacteroide and Parabacteroide)and corresponding genetic expressions responsible for extracellular hydrolysis(i.e.,clp P),membrane transport(i.e.,ffh and gsp F),intracellular substrates metabolism(i.e.,ald and paa F)and VFAs biosynthesis(i.e.,ACACA and FASN)were enhanced in the optimal presence of PHMG.Moreover,the anaerobic species could respond and adapt to low PHMG stimuli via quorum sensing(i.e.,cqs A,rpf C and rpf G),and thus maintain the high microbial metabolic activities.However,they were unable to tolerate the toxicity of excessive PHMG,resulting in the extremely low VFAs production.This work enlightened the effects of emerging pollutants on WAS fermentation at the genetic levels,and provided guidance on the WAS treatment and resource recovery.
基金supported by the National Natural Science Foundation of China(32260310,31560111)Top Young Talents Program of the Ten-Thousand Plan of Yunnan Province(YNWR-QNBJ-2018-024)Scientific Research Fund of Yunnan Provincial Education Department,China(2020Y0014)。
文摘Intestinal microbes are closely related to vital host functions such as digestion and nutrient absorption,which play important roles in enhancing host adaptability.As a natural“laboratory”,caves provide an outstanding model for understanding the significance of gut microbes and feeding habits in the habitat adaptability of hosts.However,research on the relationship between gut microbes,feeding habits,and the adaptability of troglobites remains insufficient.In this study,we compared the characteristics of the intestinal microbes of Sinocyclocheilus cavefish and surface fish and further established the relationship between intestinal and habitat microbes.Furthermore,we conducted environmental DNA(eDNA)(metabarcoding)analysis of environmental samples to clarify the composition of potential food resources in the habitats of the Sinocyclocheilus cavefish and surface fish.Results showed that the structure of the Sinocyclocheilus gut microbes was more related to ecological type(habitat type)than phylogenetic relationships.While horizontal transfer of habitat microbes was a source of gut microbes,hosts also showed strong selection for inherent microbes as dominant microorganisms.Differences in the composition and structure of gut microbes,especially dominant microbes,may enhance the adaptability of the two Sinocyclocheilus fish types from the perspectives of food intake,nutrient utilization,and harmful substance metabolism,suggesting that food resources,predation patterns,intestinal flora,digestive and absorptive capacity,and feeding habits and preferences are linked to habitat adaptability.These results should facilitate our understanding of the significance of fish gut microbes to habitat adaptation and provide a new perspective for studying the adaptive mechanisms of cavefish.
基金supported by the National Natural Science Foundation of China(52173287,52373296,51873117)Med-X Innovation Programme of Med-X Center for Materials,Sichuan University(MCMGD202304)the State Key Laboratory of Polymer Materials Engineering(sklpme2022-2-07).
文摘Mechanical adaptation of tissue engineering scaffolds is critically important since natural tissue regeneration is highly regulated by mechanical signals.Herein,we report a facile and convenient strategy to tune the modulus of waterborne biodegradable polyurethanes(WBPU)via cross-linking manipulation of phase separation and water infiltration for constructing mechanically adaptable tissue engineering scaffolds.Amorphous aliphatic polycarbonate and trifunctional trimethylolpropane were introduced to polycaprolactone-based WBPUs to interrupt interchain hydrogen bonds in the polymer segments and suppress microphase separation,inhibiting the crystallization process and enhancing covalent cross-linking.Intriguingly,as the crosslinking density of WBPU increases and the extent of microphase separation decreases,the material exhibits a surprisingly soft modulus and enhanced water infiltration.Based on this strategy,we constructed WBPU scaffolds with a tunable modulus to adapt various cells for tissue regeneration and regulate the immune response.As a representative application of brain tissue regeneration model in vivo,it was demonstrated that the mechanically adaptable WBPU scaffolds can guide the migration and differentiation of endogenous neural progenitor cells into mature neurons and neuronal neurites and regulate immunostimulation with low inflammation.Therefore,the proposed strategy of tuning the modulus of WBPU can inspire the development of novel mechanically adaptable biomaterials,which has very broad application value.
基金supported by the National Science Foundation of China(Nos.62271293,61903238)the Natural Science Foundation of Shandong Province,China(No.ZR2021MF035)the Social Science Planning Project of Shandong Province,China(No.22CYYJ13).
文摘In recent years, cyber attacks have posed great challenges to the development of cyber-physical systems. It is of great significance to study secure state estimation methods to ensure the safe and stable operation of the system. This paper proposes a secure state estimation for multi-input and multi-output continuous-time linear cyber-physical systems with sparse actuator and sensor attacks. First, for sparse sensor attacks, we propose an adaptive switching mechanism to mitigate the impact of sparse sensor attacks by filtering out their attack modes. Second, an unknown input sliding mode observer is designed to not only observe the system states, sensor attack signals, and measurement noise present in the system but also counteract the effects of sparse actuator attacks through an unknown input matrix. Finally, for the design of an unknown input sliding mode state observer, the feasibility of the observing system is demonstrated by means of Lyapunov functions. Additionally, simulation experiments are conducted to show the effectiveness of this method.
基金supported by the National Natural Science Foundation of China(32201070,32171350,32471410,32171321,81925027,32130059)Jiangsu Basic Research Program(Natural Science Founda-tion)(BK20240019,BK20240020)+3 种基金International Cooperation Project of Ningbo City(2023H013)Medical and Health Science and Technology Innovation Project of Suzhou(SKY2022105)Basic cutting-edge innovation cross project of Suzhou Medical College of Soochow University(YXY2302010)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Nucleus pulposus(NP)tissue engineering brings new hope in the repair of intervertebral disc degeneration(IVDD).IVDD is often accompanied by multiscale changes in the mechanical microenvironment,including the changes of mechanical property of collagen fibril,NP tissue,and mechanical instability of spine.In this study,a multiscale mechanically-adapted strategy is proposed to promote NP repair.To achieve this goal,a viscoelasticadapted dual-network hydrogel(PVA-DN)is constructed.The hydrogel with multiscale tunable viscoelasticity and dynamic compression condition is used to meet the multiscale mechanical requirements of NP regeneration.The results show that the viscoelastic hydrogel promotes the proliferation,migration and adhesion of nucleus pulposus cell(NPC)as well as the secretion of NP-specific extracellular matrix.RNA-seq results show that it attenuates the inflammatory microenvironment by inhibiting the IL-17 signaling pathway.Appropriate dynamic compression applied to the viscoelastic scaffold further promotes the physiological function of NPC,and the viscoelasticity of hydrogel protects against NPC damage induced by excessive compression.Animal experiments demonstrate that the viscoelastic hydrogel effectively restores disc mechanical function and delays disc degen-eration in rats.Findings from this study highlight that the multiscale mechanically-adapted strategy is effective in the repair of IVDD.
基金the National Natural Science Foundation of China(31960222,31360095).
文摘Saussurea medusa,Saussurea hypsipeta and Saussurea obvallata are typical alpine snowline plants growing in the Qinghai-Tibet plateau.They are characterized by a specialized morphology.S.medusa and S.hypsipeta have very dense trichomes on whole plant,whereas S.obvallata has transparent bracts covered inflorescences.The different forms reflect their adaptation to cold environments.To investigate the different mechanisms of adaptation of these species to cold temperatures,transcriptome sequencing was performed in three species of Saussurea DC.A total of 116394137237 and 113879 Unigenes were identified from S.medusa,S.hypsipeta and S.obvallata,respectively.Of these,55909(48.03%),65519(47.74%)and 51889(45.56%)Unigenes were matched in public databases.GO analysis identified that most of annotated Unigenes in the three species of plants were related to cellular,metabolic,and single−organism processes,and binding and catalytic activities.The differential expression of 37 genes related to environmental adaptation were discovered by pairwise comparisons.Of these,two candidate genes(Interaptin-like and CSLB3)related to trichome development were identified only in S.medusa and S.hypsipeta,which was consistent with their distinct morphology.Our data can provide a valuable resource for the further studies on the adaptive mechanisms of molecular and functional ecology in Saussurea DC.
文摘A recent study published in Cell Metabolism entitled“Gut microbial alterations in arginine metabolism determine bone mechanical adaptation”demonstrated that administration of L-arginine enhanced bone mechanical adaptation by activating a nitric oxide-calcium feedback loop in osteocytes.The findings revealed that mechanical regulation of bone adaptation is associated with gut microbiota.The underlying cause of heterogeneity of bone mechanoresponsiveness was the significant difference in the composition of the gut microbiota,in which the family Lachnospiraceae contributed to the inter-individual high variability in bone mechanical adaptation.Additionally,administration of Lachnospiraceae exhibited increased expression levels of L-citrulline and L-arginine and enhanced bone mechanoresponsiveness in recipients.Collectively,this study provides mechanistic insights into inter-individual variability of the gut microbial,which is related to the heterogeneity of bone mechanical adaptation and provides a novel preventive and therapeutic strategy to anti-osteoporotic for maximizing bone mechanoresponsiveness via the microbiota-metabolite axis.
基金Project supported by the Natural Science Foundation of Yangzhou University of China （Grant No KK0513109）.
文摘In this paper, an approach to the control of continuous-time chaotic systems is proposed using the Takagi-Sugeno （TS） fuzzy model and adaptive adjustment. Sufficient conditions are derived to guarantee chaos control from Lyapunov stability theory. The proposed approach offers a systematic design procedure for stabilizing a large class of chaotic systems in the literature about chaos research. The simulation results on Rossler＇s system verify the effectiveness of the proposed methods.
基金supported by the National Natural Science Foundation of China(61773056)the Scientific and Technological Innovation Foundation of Shunde Graduate School,University of Science and Technology Beijing(USTB)(BK19AE018)+2 种基金the Fundamental Research Funds for the Central Universities of USTB(FRF-TP-20-09B,230201606500061,FRF-DF-20-35,FRF-BD-19-002A)supported by Zhejiang Natural Science Foundation(LD21F030001)supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(Ministry of Science and Information and Communications Technology)(NRF-2020R1A2C1005449)。
文摘This paper investigates the event-triggered security consensus problem for nonlinear multi-agent systems(MASs)under denial-of-service(Do S)attacks over an undirected graph.A novel adaptive memory observer-based anti-disturbance control scheme is presented to improve the observer accuracy by adding a buffer for the system output measurements.Meanwhile,this control scheme can also provide more reasonable control signals when Do S attacks occur.To save network resources,an adaptive memory event-triggered mechanism(AMETM)is also proposed and Zeno behavior is excluded.It is worth mentioning that the AMETM's updates do not require global information.Then,the observer and controller gains are obtained by using the linear matrix inequality(LMI)technique.Finally,simulation examples show the effectiveness of the proposed control scheme.
基金supported by the National Natural Science Foundation of China under contract No.40506005
文摘Antarctic ice microalga Chlamydomonas sp. can thrive undisturbed under high UV radiation in the Antarctic ice layer. However, it is unknown that the initial adaptation mechanisms in protein level occurring in response to high UV radiation. Global-expression profiling of proteins in response to stress was analyzed by two-dimensional electrophoresis （2-DE） and image analysis. In the 2-DE analysis, protein preparation is the key step. Three different protein extract methods were compared, and the results showed that the trichloroacetic acid （TCA）-acetone fractional precipitation method was the fittest one. At the same time, the proteins in Chlamydomonas sp. were compared in 2-DE way, and the synthesis of seven protein spots was found disappeared and 18 decreased after exposed to UV-B radiation. In addition, 14 protein spots were enhanced or induced, among which two new peptides （20 and 21 kDa） appeared whose isoelectric point （pI） was 7.05 and 4.60 respectively. These changed proteins might act as key role in the acclimation of Antarctic ice microalga to UV-B radiation
基金financially supported by the National Natural Science Foundation of China(Grant No.61673260)。
文摘Marine current energy has been increasingly used because of its predictable higher power potential.Owing to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbine(MCT)system,the nonlinear controllers which rely on precise mathematical models show poor performance under a high level of parameters’uncertainties.This paper proposes an adaptive single neural control(ASNC)strategy for variable step-size perturb and observe(P&O)maximum power point tracking(MPPT)control.Firstly,to automatically update the neuron weights of SNC for the nonlinear systems,an adaptive mechanism is proposed to adaptively adjust the weighting and learning coefficients.Secondly,aiming to generate the exact reference speed for ASNC to extract the maximum power,a variable step-size law based on speed increment is designed to strike a balance between tracking speed and accuracy of P&O MPPT.The robust stability of the MCT control system is guaranteed by the Lyapunov theorem.Comparative simulation results show that this strategy has favorable adaptive performance under variable velocity conditions,and the MCT system operates at maximum power point steadily.
基金the Vietnam National Foundation for Science and Technology Development(NAFOSTED)Vietnam under Grant No.(107.01-2019.311).
文摘In this paper,a non-negative adaptive mechanism based on an adaptive nonsingular fast terminal sliding mode control strategy is proposed to have finite time and high-speed trajectory tracking for parallel manipulators with the existence of unknown bounded complex uncertainties and external disturbances.The proposed approach is a hybrid scheme of the online non-negative adaptive mechanism,tracking differentiator,and nonsingular fast terminal sliding mode control(NFTSMC).Based on the online non-negative adaptive mechanism,the proposed control can remove the assumption that the uncertainties and disturbances must be bounded for the NFTSMC controllers.The proposed controller has several advantages such as simple structure,easy implementation,rapid response,chattering-free,high precision,robustness,singularity avoidance,and finite-time convergence.Since all control parameters are online updated via tracking differentiator and non-negative adaptive law,the tracking control performance at high-speed motions can be better in real-time requirement and disturbance rejection ability.Finally,simulation results validate the effectiveness of the proposed method.
文摘Molecular mechanisms of plant responses to salinity stress and the physiological consequences of altered gene expression are reviewed. Extensive use of comparisons with halophytic plants and glycophytos provide a paradigm for many responses to salinity exhibited by stress sensitive plants. Osmolyte biosynthesis, water flux control, and membrane transport of ions are important for maintenance and re-establishment of homeostasis. Transgenic plant and mutant analyses in Arabidopsis improve the understanding of stress responses and elements of stress signal transduction pathways. The genomic DNA sequences and cell-specific transcript expression data, combined with determinant identification based on molecular genetics, will provide the infrastructure for functional physiological dissection of salt tolerance determinants in plants. Protein interaction analysis, genetic activation and suppression screens will lead inevitably to an understanding of the interrelationships of the multiple signaling systems that control stress-adaptive responses and provide more opportunity to engineer salt tolerance in plants.
基金Supported by Outstanding Youth Project of Hunan Provincial Education Department(18B461)Hunan Science and Technology Innovation Program(2019NK4170).
文摘Erigeron annuus(L.)Pers.,an alien species,is widely distributed in most areas of China.It was included in the third batch of invasive alien species list by the Ministry of Ecology and Environment of China,and it is a first-level malignant invasive plant.Due to its great reproducibility with a mass of seeds,power adaptability to the external environment and strong allelopathy,it has highly invasive and adaptability,and has affected the development of the agriculture and forestry,the diversity of local species and the ecosystem.In this paper,we summarized the current invasion situation,invasion and adaptation mechanism of E.annuus,and prospected further research on E.annuus invasion mechanism,hoping to provide a reference for realizing its effective management.
文摘For exchanging and sharing information and services in e-government, a framework of information service platform (ISP) is presented. The multi-layer architecture of the ISP is introduced. They are. user's requirement layer, business service layer, business process layer, business function layer and data layer. The lower layers are based on the architecture of web services and the upper layers are related to the institutional and organizational issues. In order to deal with the variation of user's requirements and changing environment, the matching and mapping processes with adaptive mechanism are illustrated.
