<正>A novel neurochip based on light addressable potentiometric sensor (LAPS) is designed.Using its light addressable characteristic.The problems of the limitations of restricted discrete active sites of current...<正>A novel neurochip based on light addressable potentiometric sensor (LAPS) is designed.Using its light addressable characteristic.The problems of the limitations of restricted discrete active sites of current neurochips,such as microelectrode array and field effect transistor array can be settled easily.Based on the theoretical analysis of the interface between cells and LAPS,spontaneously discharges of hippocampal neurons induced by Mg~ 2+)-free media treatment were recorded by LAPS.The results demonstrate that this kind of neurochip has potential to monitor electrophysiology of cultured cells in a non-invasive way.展开更多
Cellular metabolism arouses the changes of substance in extracellular physiological microenvironment,and the metabolic level reflects the physiological state of cells.This paper developed a novel microphysiometer auto...Cellular metabolism arouses the changes of substance in extracellular physiological microenvironment,and the metabolic level reflects the physiological state of cells.This paper developed a novel microphysiometer automatic analysis instrument based on multiparameter cell-based biosensors for quick drug analysis.This study included the multiparameter cell-based biosensors,cell culture chamber,drug auto-injection detection and analysis.The analysis instrument was capable of real-time detection for the acidic product and other chemical parameters generated by the cellular metabolism in the micro-volume.Finally,the paper employs human breast cancer cell line MCF-7 and drug experiments to verify the performance of microphysiometer,and study effects of different drugs on cell metabolism.Further,the research explores drug analysis method of the multiparameter microphysiometer.The results showed that the cell-based microphysiometer system provides a utility platform for rapid,long-term and automatic cell physiological environment detection and drug analysis.展开更多
The light-addressable potentiometric sensor (LAPS) is a semiconductor-based cellular biosensor with an electrolyte-insulator-semiconductor (EIS) structure.By depositing biocompatible layers on the sensing surface fo...The light-addressable potentiometric sensor (LAPS) is a semiconductor-based cellular biosensor with an electrolyte-insulator-semiconductor (EIS) structure.By depositing biocompatible layers on the sensing surface for cell culture, it can be used to detect bioelectrical parameters of cells.The characteristic curve for photocurrent versus applied bias voltage to the system shows a current-voltage curve (Ⅰ-Ⅴcurve).This technique can be used to detect the action potential changes towards different drugs based on the bias voltage dependence of an optical current,and provides a dynamic system by scanning light beam at the very cell on the sensor device.The LAPS overcomes the limitation of recording sites,but high spatial resolution and sensitivity are also paramount.This paper discussed a novel structure of LAPS array for extracellular monitoring to decrease potential noise level.Both characteristics of active recording array areas and cell culture conditions are measured.展开更多
Predicting demand for bike share systems(BSSs)is critical for both the management of an existing BSS and the planning for a new BSS.While researchers have mainly focused on improving prediction accuracy and analysing ...Predicting demand for bike share systems(BSSs)is critical for both the management of an existing BSS and the planning for a new BSS.While researchers have mainly focused on improving prediction accuracy and analysing demand-influencing factors,there are few studies examining the inherent randomness of stations'observed demands and to what degree the demands at individual stations are predictable.Using Divvy bike-share one-year data from Chicago,USA,we measured demand entropy and quantified the station-level predictability.Additionally,to verify that these predictability measures could represent the performance of prediction models,we implemented two commonly used demand prediction models to compare the empirical prediction accuracy with the calculated entropy and predictability.Furthermore,we explored how city-and system-specific temporallyconstant features would impact entropy and predictability to inform estimating these measures when historical demand data are unavailable.Our results show that entropy and predictability of demands across stations are polarized as some stations exhibit high uncertainty(a low predictability of 0.65)and others have almost no check-out demand uncertainty(a high predictability of around 1.0).We also validated that the entropy and predictability are a priori model-free indicators for prediction error,given a sequence of bike usage demands.Lastly,we identified that key factors contributing to station-level entropy and predictability include per capita income,spatial eccentricity,and the number of parking lots near the station.Findings from this study provide more fundamental understanding of BSS demand prediction,which can help decision makers and system operators anticipate diverse stationlevel prediction errors from their prediction models both for existing stations and for new ones.展开更多
The pollution caused by agricultural production poses a threat to the ecological integrity of river ecosystems,altering the structure and function of river ecosystems.Differences in microbial community structure provi...The pollution caused by agricultural production poses a threat to the ecological integrity of river ecosystems,altering the structure and function of river ecosystems.Differences in microbial community structure provide useful information about the impact of agricultural pollution on the biological integrity of ecosystems,but generally convey little information regarding ecosystem functions.In this study,using Illumina MiSeq sequencing technology based on the 16 S rRNA gene,river sediment samples associated with four different types of agricultural pollution were comprehensively analyzed.The results show that the total organic carbon(TOC)content was highest at the YZS site(animal husbandry sewage)among the assayed sites,but the species richness and uniformity were lowest at this site,which may have been caused by the high nutrient source of the sewage.Furthermore,in the three YZS samples affected by the long-term discharge of aquaculture tail-water,the unique genus Dechloromonas and the genus Candidatus-Competitor were observed,which are strongly correlated with phosphorus conversion.The formation of network modules may correspond to the coexistence of functional bacteria accustomed to multiple niche combinations under different agricultural pollution conditions in river sediments.According to the PICRUSt functional prediction,the bacterial community in the agricultural polluted river sediment primarily harbored 46 subfunctions,exhibiting richness of functions.Overall,our results provide a more comprehensive understanding of the structure and ecological processes associated with the aggregation of bacterial communities,which is beneficial for the management of river environments.展开更多
A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we prove that every 1-planar graph G with maximum degree △(G) 〉 12 and girth at least five...A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we prove that every 1-planar graph G with maximum degree △(G) 〉 12 and girth at least five is totally (△(G)+1)-colorable.展开更多
The growing scale and complexity of component interactions in cloud computing systems post great challenges for operators to understand the characteristics of system performance. Profiling has long been proved to be a...The growing scale and complexity of component interactions in cloud computing systems post great challenges for operators to understand the characteristics of system performance. Profiling has long been proved to be an effective approach to performance analysis; however, existing approaches confront new challenges that emerge in cloud computing systems. First, the efficiency of the profiling becomes of critical concern; second, service-oriented profiling should be considered to support separation-of-concerns performance analysis. To address the above issues, in this paper, we present P-Tracer, an online performance profiling tool specifically tailored for cloud computing systems. P-Tracer constructs a specific search engine that proactively processes performance logs and generates a particular index for fast queries; second, for each service, P-Tracer retrieves a statistical insight of performance characteristics from multi-dimensions and provides operators with a suite of web-based interfaces to query the critical information. We evaluate P- Tracer in the aspects of tracing overheads, data preprocessing scalability and querying efficiency. Three real-world case studies that happened in Alibaba cloud computing platform demonstrate that P-Tracer can help operators understand soft-ware behaviors and localize the primary causes of performance anomalies effectively and efficiently.展开更多
In this study,photovoltage technique is applied in the development of a monolithically integrated sensor for redox(reduction–oxidation)potential and pH measurement.The sensor employs the electrolyte–insulator–semic...In this study,photovoltage technique is applied in the development of a monolithically integrated sensor for redox(reduction–oxidation)potential and pH measurement.The sensor employs the electrolyte–insulator–semiconductor structure,with deposition of a layer of gold metal on partial surface of insulator silicon dioxide.Silicon dioxide and gold layer on a single chip form two distinct sensing sites,by sharing the same measuring system,the detection of redox potential and pH variation can be realized.In this work,the sensor characteristics is tested,and the sensitivity for redox potential and pH measurement is53.8 mV/log([Fe(II)]/[Fe(III)])and 44.3 mV/pH respectively.To demonstrate the validity of the sensor in extracellular detection,neonatal rat kidney cells are cultured on the sensor surface and then packaged in a flow chamber,thus the acidification rate of metabolites and the redox potential variation in extracellular microenvironment can be continuously monitored.Experimental results indicate increasing acidification and reducing potentials under physiological conditions.The synthesis parameters have potentials in detail revelation of cell metabolism.展开更多
A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we verify the total coloring conjecture for every 1-planar graph G if either △(G) ≥9 and g...A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we verify the total coloring conjecture for every 1-planar graph G if either △(G) ≥9 and g(G)≥ 4, or △(G) ≥ 7 and g(G)≥5, where △(G) is the maximum degree of G and g(G) is the girth of G.展开更多
A k-total-coloring of a graph G is a coloring of vertices and edges of G using k colors such that no two adjacent or incident elements receive the same color.In this paper,it is proved that if G is a planar graph with...A k-total-coloring of a graph G is a coloring of vertices and edges of G using k colors such that no two adjacent or incident elements receive the same color.In this paper,it is proved that if G is a planar graph with Δ(G) ≥ 7 and without chordal 7-cycles,then G has a(Δ(G) + 1)-total-coloring.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.30270387,No.30570492)the Project of State Key Laboratory of Transducer Technology of China(Grant No.SKT0403)the Foundation for the Bureau of Zhejiang Province of China(Grant No.20040197).
文摘<正>A novel neurochip based on light addressable potentiometric sensor (LAPS) is designed.Using its light addressable characteristic.The problems of the limitations of restricted discrete active sites of current neurochips,such as microelectrode array and field effect transistor array can be settled easily.Based on the theoretical analysis of the interface between cells and LAPS,spontaneously discharges of hippocampal neurons induced by Mg~ 2+)-free media treatment were recorded by LAPS.The results demonstrate that this kind of neurochip has potential to monitor electrophysiology of cultured cells in a non-invasive way.
基金This work was supported by the National Natural Science Foundation of China(Grant No.81027003)the Zhejiang Provincial Science and Technology Major Special Program(No.2010C14006).
文摘Cellular metabolism arouses the changes of substance in extracellular physiological microenvironment,and the metabolic level reflects the physiological state of cells.This paper developed a novel microphysiometer automatic analysis instrument based on multiparameter cell-based biosensors for quick drug analysis.This study included the multiparameter cell-based biosensors,cell culture chamber,drug auto-injection detection and analysis.The analysis instrument was capable of real-time detection for the acidic product and other chemical parameters generated by the cellular metabolism in the micro-volume.Finally,the paper employs human breast cancer cell line MCF-7 and drug experiments to verify the performance of microphysiometer,and study effects of different drugs on cell metabolism.Further,the research explores drug analysis method of the multiparameter microphysiometer.The results showed that the cell-based microphysiometer system provides a utility platform for rapid,long-term and automatic cell physiological environment detection and drug analysis.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 30270387, No. 30570492);the Project of State Key Laboratory of Transducer Technology of China (Grant No. SKT0403);the Foundation for the Bureau of Zhejiang Province of China (Grant No. 20040197).
文摘The light-addressable potentiometric sensor (LAPS) is a semiconductor-based cellular biosensor with an electrolyte-insulator-semiconductor (EIS) structure.By depositing biocompatible layers on the sensing surface for cell culture, it can be used to detect bioelectrical parameters of cells.The characteristic curve for photocurrent versus applied bias voltage to the system shows a current-voltage curve (Ⅰ-Ⅴcurve).This technique can be used to detect the action potential changes towards different drugs based on the bias voltage dependence of an optical current,and provides a dynamic system by scanning light beam at the very cell on the sensor device.The LAPS overcomes the limitation of recording sites,but high spatial resolution and sensitivity are also paramount.This paper discussed a novel structure of LAPS array for extracellular monitoring to decrease potential noise level.Both characteristics of active recording array areas and cell culture conditions are measured.
文摘Predicting demand for bike share systems(BSSs)is critical for both the management of an existing BSS and the planning for a new BSS.While researchers have mainly focused on improving prediction accuracy and analysing demand-influencing factors,there are few studies examining the inherent randomness of stations'observed demands and to what degree the demands at individual stations are predictable.Using Divvy bike-share one-year data from Chicago,USA,we measured demand entropy and quantified the station-level predictability.Additionally,to verify that these predictability measures could represent the performance of prediction models,we implemented two commonly used demand prediction models to compare the empirical prediction accuracy with the calculated entropy and predictability.Furthermore,we explored how city-and system-specific temporallyconstant features would impact entropy and predictability to inform estimating these measures when historical demand data are unavailable.Our results show that entropy and predictability of demands across stations are polarized as some stations exhibit high uncertainty(a low predictability of 0.65)and others have almost no check-out demand uncertainty(a high predictability of around 1.0).We also validated that the entropy and predictability are a priori model-free indicators for prediction error,given a sequence of bike usage demands.Lastly,we identified that key factors contributing to station-level entropy and predictability include per capita income,spatial eccentricity,and the number of parking lots near the station.Findings from this study provide more fundamental understanding of BSS demand prediction,which can help decision makers and system operators anticipate diverse stationlevel prediction errors from their prediction models both for existing stations and for new ones.
基金the Key University Science Research Project of Anhui Province(No.KJ2019A0641)the Key Research and development program of Anhui Province(No.202004i07020010)+1 种基金the Resistance in Winter Wheat Region in the Middle and Lower Reaches of the Yangtze River(No.2017YFD0100800)the Anhui Academy of Agricultural Sciences Research and Application Innovation Team Project of Aquaculture Water Environment(No.2020YL043)。
文摘The pollution caused by agricultural production poses a threat to the ecological integrity of river ecosystems,altering the structure and function of river ecosystems.Differences in microbial community structure provide useful information about the impact of agricultural pollution on the biological integrity of ecosystems,but generally convey little information regarding ecosystem functions.In this study,using Illumina MiSeq sequencing technology based on the 16 S rRNA gene,river sediment samples associated with four different types of agricultural pollution were comprehensively analyzed.The results show that the total organic carbon(TOC)content was highest at the YZS site(animal husbandry sewage)among the assayed sites,but the species richness and uniformity were lowest at this site,which may have been caused by the high nutrient source of the sewage.Furthermore,in the three YZS samples affected by the long-term discharge of aquaculture tail-water,the unique genus Dechloromonas and the genus Candidatus-Competitor were observed,which are strongly correlated with phosphorus conversion.The formation of network modules may correspond to the coexistence of functional bacteria accustomed to multiple niche combinations under different agricultural pollution conditions in river sediments.According to the PICRUSt functional prediction,the bacterial community in the agricultural polluted river sediment primarily harbored 46 subfunctions,exhibiting richness of functions.Overall,our results provide a more comprehensive understanding of the structure and ecological processes associated with the aggregation of bacterial communities,which is beneficial for the management of river environments.
基金supported by National Natural Science Foundation of China(Grant No.11271006)
文摘A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we prove that every 1-planar graph G with maximum degree △(G) 〉 12 and girth at least five is totally (△(G)+1)-colorable.
基金This research was supported by the National Basic Research Program of China (2011CB302600), the National High Technology Research and Development Program of China (2012AA011201), the National Natural Science Foundation of China (Grant Nos. 61161160565, 90818028, 91118008, 60903043), and an NSFC/RGC Joint Research Scheme sponsored by the Research Grants Council of Hong Kong, China and National Natural Science Foundation of China Project (JC201104220300A).
文摘The growing scale and complexity of component interactions in cloud computing systems post great challenges for operators to understand the characteristics of system performance. Profiling has long been proved to be an effective approach to performance analysis; however, existing approaches confront new challenges that emerge in cloud computing systems. First, the efficiency of the profiling becomes of critical concern; second, service-oriented profiling should be considered to support separation-of-concerns performance analysis. To address the above issues, in this paper, we present P-Tracer, an online performance profiling tool specifically tailored for cloud computing systems. P-Tracer constructs a specific search engine that proactively processes performance logs and generates a particular index for fast queries; second, for each service, P-Tracer retrieves a statistical insight of performance characteristics from multi-dimensions and provides operators with a suite of web-based interfaces to query the critical information. We evaluate P- Tracer in the aspects of tracing overheads, data preprocessing scalability and querying efficiency. Three real-world case studies that happened in Alibaba cloud computing platform demonstrate that P-Tracer can help operators understand soft-ware behaviors and localize the primary causes of performance anomalies effectively and efficiently.
基金supported by the National Nat-ural Science Foundation of China(81027003)the National Basic Research Program of China(2009CB320303)the National Public Welfare Project of China(201305010)
文摘In this study,photovoltage technique is applied in the development of a monolithically integrated sensor for redox(reduction–oxidation)potential and pH measurement.The sensor employs the electrolyte–insulator–semiconductor structure,with deposition of a layer of gold metal on partial surface of insulator silicon dioxide.Silicon dioxide and gold layer on a single chip form two distinct sensing sites,by sharing the same measuring system,the detection of redox potential and pH variation can be realized.In this work,the sensor characteristics is tested,and the sensitivity for redox potential and pH measurement is53.8 mV/log([Fe(II)]/[Fe(III)])and 44.3 mV/pH respectively.To demonstrate the validity of the sensor in extracellular detection,neonatal rat kidney cells are cultured on the sensor surface and then packaged in a flow chamber,thus the acidification rate of metabolites and the redox potential variation in extracellular microenvironment can be continuously monitored.Experimental results indicate increasing acidification and reducing potentials under physiological conditions.The synthesis parameters have potentials in detail revelation of cell metabolism.
基金Supported by the scientific research program of Xinjiang Uygur Autonomous Region grant 2016D01C012 the Scientific Research Program(XJEDU2016I046)of the Higher Education Institution of Xinjiang
文摘A graph is 1-planar if it can be drawn on the plane so that each edge is crossed by at most one other edge. In this paper, we verify the total coloring conjecture for every 1-planar graph G if either △(G) ≥9 and g(G)≥ 4, or △(G) ≥ 7 and g(G)≥5, where △(G) is the maximum degree of G and g(G) is the girth of G.
基金Supported by National Natural Science Foundation of China(Grant No.11271006)
文摘A k-total-coloring of a graph G is a coloring of vertices and edges of G using k colors such that no two adjacent or incident elements receive the same color.In this paper,it is proved that if G is a planar graph with Δ(G) ≥ 7 and without chordal 7-cycles,then G has a(Δ(G) + 1)-total-coloring.