PhoR is a histidine kinase in a two-component regulatory system that regulates phosphorus metabolic pathways and undertakes the key mission of information transmission in pathogenic bacteria.The full-length phoR gene ...PhoR is a histidine kinase in a two-component regulatory system that regulates phosphorus metabolic pathways and undertakes the key mission of information transmission in pathogenic bacteria.The full-length phoR gene was successfully cloned from the Vibrio alginolyticus HY9901 strain.A comprehensive analysis of the cloned gene was conducted using bioinformatics.Sequence analysis revealed that the total length of the phoR gene(GenBank accession No.:KJ958404.1)is 1299 bp,with the coding region containing a total of 432 amino acid residues.The phylogenetic tree of PhoR revealed that it belongs to the same subclade as V.diabolicus.The SMART program was employed for the purpose of functional domain prediction,which revealed that PhoR possesses three major functional domains:PAS(amino acids 98-166),HisKA(amino acids 205-272),and HATPase_c(amino acids 317-429).展开更多
Vibrio alginolyticus is a zoonotic bacterium.A pair of specific primers was designed using the sodB gene sequence of Vibrio alginolyticus HY9901 in order to amplify the full length of the gene by PCR.The results indic...Vibrio alginolyticus is a zoonotic bacterium.A pair of specific primers was designed using the sodB gene sequence of Vibrio alginolyticus HY9901 in order to amplify the full length of the gene by PCR.The results indicated that the total length of the sodB gene was 585 bp and that it could encode 194 amino acids.The predicted amino acid sequence derivation indicated that the molecular weight of the protein was approximately 21.56 kDa,with an isoelectric point of 4.95.Upon prediction of the N-terminal signal peptide structure of the protein,no significant signal peptide cleavage site was observed,indicating that the protein lacked both a signal peptide and a transmembrane region.The amino acid sequence contained an N-glycosylation site,a casein kinase II phosphorylation site,a microsomal C-terminal target signal site,and a manganese and iron superoxide dismutase signal site.The probability of intracytoplasmic localization of the SodB protein was 56.5%,which was analyzed according to the subcellular localization of the protein.The amino acid sequence of the sodB gene of V.alginolyticus exhibited 98%-100%homology to other Vibrio species,clustering into the same subfamily with V.parahaem,indicating a relatively close relationship between them.In the prediction of protein structure,the proportions ofα-helix,random coil,β-sheet,and extended strand were 48.45%,30.41%,5.67%,and 15.46%,respectively.The similarity to template 1dt0.1.A reached 71.58%.A PTM site analysis revealed the presence of phosphorylation,glycosylation,ubiquitination,sumoylation,acetylation,and methylation modification sites,as well as the absence of lactylation modification sites.展开更多
The effects of testing solutions and conditions on hydroxyapatite(HAp)formation as a means of in vitro bioactivity evaluation of B2O3 containing 45S5 bioactive glasses were systematically investigated.Four glass sampl...The effects of testing solutions and conditions on hydroxyapatite(HAp)formation as a means of in vitro bioactivity evaluation of B2O3 containing 45S5 bioactive glasses were systematically investigated.Four glass samples prepared by the traditional melt and quench process,where SiO2 in 45S5 was gradually replaced by B2O3(up to 30%),were studied.Two solutions:the simulated body fluid(SBF)and K2HPO4 solutions were used as the medium for evaluating in vitro bioactivity through the formation of HAp on glass surface as a function of time.It was found that addition of boron oxide delayed the HAp formation in both SBF and K2HPO4 solutions,while the reaction between glass and the K2HPO4 solution is much faster as compared to SBF.In addition to the composition and medium effects,we also studied whether the solution treatments(e.g.,adjusting to maintain a pH of 7.4,refreshing solution at certain time interval,and no disturbance during immersion)affect HAp formation.Fourier transform infrared spectrometer(FTIR)equipped with an attenuated total reflection(ATR)sampling technique and scanning electron microscopy(SEM)were conducted to identify HAp formation on glass powder surfaces and to observe HAp morphologies,respectively.The results show that refreshing solution every 24 h produced the fastest HAp formation for low boron-containing samples when SBF was used as testing solution,while no significant differences were observed when K2HPO4 solution was used.This study thus suggests the testing solutions and conditions play an important role on the in vitro bioactivity testing results and should be carefully considered when study materials with varying bioactivities.展开更多
Soft open points(SOPs)are power electronic devices that may replace conventional normally-open points in distribution networks.They can be used for active power flow control,reactive power compensation,fault isolation...Soft open points(SOPs)are power electronic devices that may replace conventional normally-open points in distribution networks.They can be used for active power flow control,reactive power compensation,fault isolation,and service restoration through network reconfiguration with enhanced operation flexibility and grid resiliency.Due to unbalanced loading conditions,the voltage unbalance issue,as a common problem in distribution networks,has negative impacts on distribution network operation.In this paper,a control strategy of voltage unbalance compensation for feeders using SOPs is proposed.With the power flow control,three-phase current is regulated simultaneously to mitigate the unbalanced voltage between neighboring feeders where SOPs are installed.Feeder voltage unbalance and current unbalance among three phases are compensated with the injection of negative-sequence and zero-sequence current from SOPs.Especially in response to power outages,three-phase voltage of isolated loads is regulated to be balanced by the control of SOPs connected to the feeders under faults,even if the loads are unbalanced.A MATLAB/Simulink model of the IEEE 13-bus test feeder with an SOP across feeder ends is implemented,and experimental tests on a hardware-in-the-loop platform are implemented to validate the effectiveness of the proposed control strategy.展开更多
This paper presents an Multi-Input Multi-Output(MIMO)analysis to investigate the mutual interactions and small-signal stability of bipolar-type dc microgrids.Since bipolar dc microgrid is replete with power-electronic...This paper presents an Multi-Input Multi-Output(MIMO)analysis to investigate the mutual interactions and small-signal stability of bipolar-type dc microgrids.Since bipolar dc microgrid is replete with power-electronic converters,its dynamics can not be understood unless the interactions among control systems of converters are properly investigated.To tackle the challenge,each converter in microgrid is modeled via an MIMO transfer matrix.Then,the MIMO models are combined together based on the interactions among the control systems of source and load converters.From this integrative MIMO model,the mutual interactions between various input-output pairs are quantified using Gershgorin Band theorem.Also,Singular Value Decomposition(SVD)analysis is carried out to estimate the frequency of unstable poles.Test results not only successfully validate the effectiveness of the MIMO method but also show that the control system of voltage balancer has a major impact on the overall stability of bipolar dc microgrid,making it a suitable location for applying damping systems.展开更多
Metallic implant materials possess adequate mechanical properties such as strength,elastic modulus,and ductility for long term support and stability in vivo.Traditional metallic biomaterials,including stainless steels...Metallic implant materials possess adequate mechanical properties such as strength,elastic modulus,and ductility for long term support and stability in vivo.Traditional metallic biomaterials,including stainless steels,cobalt-chromium alloys,and titanium and its alloys,have been the gold standards for load-bearing implant materials in hard tissue applications in the past decades.Biodegradable metals including iron,magnesium,and zinc have also emerged as novel biodegradable implant materials with different in vivo degradation rates.However,they do not possess good bioactivity and other biological functions.Bioactive glasses have been widely used as coating materials on the metallic implants to improve their integration with the host tissue and overall biological performances.The present review provides a detailed overview of the benefits and issues of metal alloys when used as biomedical implants and how they are improved by bioactive glass-based coatings for biomedical applications.展开更多
Due to the increased demand for ready-to-eat(RTE)minimally processed foods,alternatives to chemical and thermal preservation methods to maintain food safety are highly demanded.A significant safety hazard in RTE food ...Due to the increased demand for ready-to-eat(RTE)minimally processed foods,alternatives to chemical and thermal preservation methods to maintain food safety are highly demanded.A significant safety hazard in RTE food products is the growth of the foodborne pathogen Listeria monocytogenes(L.monocytogenes).After processing,recontamination or cross-contamination of L.monocytogenes in RTE food products may occur and the lack of cooking can lead to an increased risk of listeriosis.Further,some RTE food products(e.g.cheese and cured meat)can have a long processing period and shelf life,thus allowing for the growth and proliferation of L.monocytogenes in the food matrix.Lactic acid bacteria(LAB)are generally recognized as safe probiotics and have been proposed as a biological control approach to eliminate foodborne pathogens including L.monocytogenes.LAB have been reported to extend the shelf life of food products and inhibit pathogen proliferation via growth competition and metabolite production.LAB are native microflora of many RTE foods,but only certain LAB may inhibit pathogen growth.Therefore,the specificity of LAB species should be employed in their use in RTE foods.This review will discuss the antimicrobial mechanisms of LAB against L.monocytogenes,selective use of LAB in food matrices,and their uses in food processing and packaging.展开更多
In this paper,an improved active stabilization strategy of the interface converters in microgrid applications is proposed on the basis of the passivity-based stability criterion(PBSC).As a critical part of AC and DC h...In this paper,an improved active stabilization strategy of the interface converters in microgrid applications is proposed on the basis of the passivity-based stability criterion(PBSC).As a critical part of AC and DC hybrid microgrids,the DC microgrid is taken as an example.In particular,a stabilization method with a proportional-integral(PI)controller and firstorder high-pass filter(HPF)is proposed to meet the passivity requirements of the overall control diagram with respect to the output voltage.Meanwhile,an output current feedback control loop is introduced to ensure the output impedance passivity.Moreover,a small-signal model of the parallel interface converter system is established to comprehensively study the influence of control parameters on the passivity of the converters.Based on the active stabilization method proposed in this study,by manipulating the control diagram of each interface converter,the passivity and stability of the DC microgrids with variable configuration can be guaranteed.Therefore,a generic and simplified design approach is realized.A simulation model with three interface converters is implemented in MATLAB/Simulink,and the effectiveness of the proposed passivity-based active stabilization algorithm is verified by using this simulation model.展开更多
As a growing number of microgrids(MGs)has been integrated into the modern power grids,the interconnection and applicable cooperation among multiple MGs motivate the development of networked MGs.Dynamic MGs,as an advan...As a growing number of microgrids(MGs)has been integrated into the modern power grids,the interconnection and applicable cooperation among multiple MGs motivate the development of networked MGs.Dynamic MGs,as an advanced networked MGs structure,can not only integrate multiple MGs into the distribution system but also fulfill the requested system network reconfiguration with improved flexibility.A general distributed control approach for networked MGs is reviewed.A distributed control framework for dynamic MGs operation is developed,along with an extensible architecture with considerations of large-scale distributed energy resources(DERs)integration.A scalable small-signal stability analysis is conducted per the proposed distributed control strategies and the conditions under which the system is exponentially stable are derived.At last,the effectiveness of the proposed control framework and stability analysis are verified using a 6-bus test feeder.展开更多
基金Supported by Outstanding Graduate Entering Laboratory Project of College of Fisheries,Guangdong Ocean UniversityNational Natural Science Foundation of China(32073015)+1 种基金Undergraduate Innovation Team of Guangdong Ocean University(CCTD201802)Undergraduate Innovation and Entrepreneurship Training Program of Guangdong Ocean University(CXXL2024007).
文摘PhoR is a histidine kinase in a two-component regulatory system that regulates phosphorus metabolic pathways and undertakes the key mission of information transmission in pathogenic bacteria.The full-length phoR gene was successfully cloned from the Vibrio alginolyticus HY9901 strain.A comprehensive analysis of the cloned gene was conducted using bioinformatics.Sequence analysis revealed that the total length of the phoR gene(GenBank accession No.:KJ958404.1)is 1299 bp,with the coding region containing a total of 432 amino acid residues.The phylogenetic tree of PhoR revealed that it belongs to the same subclade as V.diabolicus.The SMART program was employed for the purpose of functional domain prediction,which revealed that PhoR possesses three major functional domains:PAS(amino acids 98-166),HisKA(amino acids 205-272),and HATPase_c(amino acids 317-429).
基金Supported by Outstanding Graduate Entering Laboratory Project of College of Fisheries,Guangdong Ocean UniversityNational Natural Science Foundation of China(32073015)+1 种基金Undergraduate Innovation and Entrepreneurship Training Program of Guangdong Ocean University(CXXL2024007)Undergraduate Innovation Team of Guangdong Ocean University(CCTD201802).
文摘Vibrio alginolyticus is a zoonotic bacterium.A pair of specific primers was designed using the sodB gene sequence of Vibrio alginolyticus HY9901 in order to amplify the full length of the gene by PCR.The results indicated that the total length of the sodB gene was 585 bp and that it could encode 194 amino acids.The predicted amino acid sequence derivation indicated that the molecular weight of the protein was approximately 21.56 kDa,with an isoelectric point of 4.95.Upon prediction of the N-terminal signal peptide structure of the protein,no significant signal peptide cleavage site was observed,indicating that the protein lacked both a signal peptide and a transmembrane region.The amino acid sequence contained an N-glycosylation site,a casein kinase II phosphorylation site,a microsomal C-terminal target signal site,and a manganese and iron superoxide dismutase signal site.The probability of intracytoplasmic localization of the SodB protein was 56.5%,which was analyzed according to the subcellular localization of the protein.The amino acid sequence of the sodB gene of V.alginolyticus exhibited 98%-100%homology to other Vibrio species,clustering into the same subfamily with V.parahaem,indicating a relatively close relationship between them.In the prediction of protein structure,the proportions ofα-helix,random coil,β-sheet,and extended strand were 48.45%,30.41%,5.67%,and 15.46%,respectively.The similarity to template 1dt0.1.A reached 71.58%.A PTM site analysis revealed the presence of phosphorylation,glycosylation,ubiquitination,sumoylation,acetylation,and methylation modification sites,as well as the absence of lactylation modification sites.
基金support of the NSF Ceramics program(project#1508001)support of the NSF REU program(project#1461048)。
文摘The effects of testing solutions and conditions on hydroxyapatite(HAp)formation as a means of in vitro bioactivity evaluation of B2O3 containing 45S5 bioactive glasses were systematically investigated.Four glass samples prepared by the traditional melt and quench process,where SiO2 in 45S5 was gradually replaced by B2O3(up to 30%),were studied.Two solutions:the simulated body fluid(SBF)and K2HPO4 solutions were used as the medium for evaluating in vitro bioactivity through the formation of HAp on glass surface as a function of time.It was found that addition of boron oxide delayed the HAp formation in both SBF and K2HPO4 solutions,while the reaction between glass and the K2HPO4 solution is much faster as compared to SBF.In addition to the composition and medium effects,we also studied whether the solution treatments(e.g.,adjusting to maintain a pH of 7.4,refreshing solution at certain time interval,and no disturbance during immersion)affect HAp formation.Fourier transform infrared spectrometer(FTIR)equipped with an attenuated total reflection(ATR)sampling technique and scanning electron microscopy(SEM)were conducted to identify HAp formation on glass powder surfaces and to observe HAp morphologies,respectively.The results show that refreshing solution every 24 h produced the fastest HAp formation for low boron-containing samples when SBF was used as testing solution,while no significant differences were observed when K2HPO4 solution was used.This study thus suggests the testing solutions and conditions play an important role on the in vitro bioactivity testing results and should be carefully considered when study materials with varying bioactivities.
基金The work of R.You was supported by Shandong Provincial Key Research and Development Program(No.2019JZZY010902)Shandong Provincial Natural Science Foundation(No.ZR2020ME197).
文摘Soft open points(SOPs)are power electronic devices that may replace conventional normally-open points in distribution networks.They can be used for active power flow control,reactive power compensation,fault isolation,and service restoration through network reconfiguration with enhanced operation flexibility and grid resiliency.Due to unbalanced loading conditions,the voltage unbalance issue,as a common problem in distribution networks,has negative impacts on distribution network operation.In this paper,a control strategy of voltage unbalance compensation for feeders using SOPs is proposed.With the power flow control,three-phase current is regulated simultaneously to mitigate the unbalanced voltage between neighboring feeders where SOPs are installed.Feeder voltage unbalance and current unbalance among three phases are compensated with the injection of negative-sequence and zero-sequence current from SOPs.Especially in response to power outages,three-phase voltage of isolated loads is regulated to be balanced by the control of SOPs connected to the feeders under faults,even if the loads are unbalanced.A MATLAB/Simulink model of the IEEE 13-bus test feeder with an SOP across feeder ends is implemented,and experimental tests on a hardware-in-the-loop platform are implemented to validate the effectiveness of the proposed control strategy.
基金This work was supported by the U.S.National Science Foundation under Grant Nos.1647209 and 1611095the European Unions Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant No.765585.
文摘This paper presents an Multi-Input Multi-Output(MIMO)analysis to investigate the mutual interactions and small-signal stability of bipolar-type dc microgrids.Since bipolar dc microgrid is replete with power-electronic converters,its dynamics can not be understood unless the interactions among control systems of converters are properly investigated.To tackle the challenge,each converter in microgrid is modeled via an MIMO transfer matrix.Then,the MIMO models are combined together based on the interactions among the control systems of source and load converters.From this integrative MIMO model,the mutual interactions between various input-output pairs are quantified using Gershgorin Band theorem.Also,Singular Value Decomposition(SVD)analysis is carried out to estimate the frequency of unstable poles.Test results not only successfully validate the effectiveness of the MIMO method but also show that the control system of voltage balancer has a major impact on the overall stability of bipolar dc microgrid,making it a suitable location for applying damping systems.
基金funded by the National Institutes of Health(Grant number R01HL140562)National Science Foundation DMR Ceramics Program(Grant number:1508001).
文摘Metallic implant materials possess adequate mechanical properties such as strength,elastic modulus,and ductility for long term support and stability in vivo.Traditional metallic biomaterials,including stainless steels,cobalt-chromium alloys,and titanium and its alloys,have been the gold standards for load-bearing implant materials in hard tissue applications in the past decades.Biodegradable metals including iron,magnesium,and zinc have also emerged as novel biodegradable implant materials with different in vivo degradation rates.However,they do not possess good bioactivity and other biological functions.Bioactive glasses have been widely used as coating materials on the metallic implants to improve their integration with the host tissue and overall biological performances.The present review provides a detailed overview of the benefits and issues of metal alloys when used as biomedical implants and how they are improved by bioactive glass-based coatings for biomedical applications.
文摘Due to the increased demand for ready-to-eat(RTE)minimally processed foods,alternatives to chemical and thermal preservation methods to maintain food safety are highly demanded.A significant safety hazard in RTE food products is the growth of the foodborne pathogen Listeria monocytogenes(L.monocytogenes).After processing,recontamination or cross-contamination of L.monocytogenes in RTE food products may occur and the lack of cooking can lead to an increased risk of listeriosis.Further,some RTE food products(e.g.cheese and cured meat)can have a long processing period and shelf life,thus allowing for the growth and proliferation of L.monocytogenes in the food matrix.Lactic acid bacteria(LAB)are generally recognized as safe probiotics and have been proposed as a biological control approach to eliminate foodborne pathogens including L.monocytogenes.LAB have been reported to extend the shelf life of food products and inhibit pathogen proliferation via growth competition and metabolite production.LAB are native microflora of many RTE foods,but only certain LAB may inhibit pathogen growth.Therefore,the specificity of LAB species should be employed in their use in RTE foods.This review will discuss the antimicrobial mechanisms of LAB against L.monocytogenes,selective use of LAB in food matrices,and their uses in food processing and packaging.
基金This work was supported in part by the National Natural Science Foundation of China(Nos.51137003,61233008 and 51520105011)and in part by the Special Project of International Scientific and Technological Cooperation of China(No.2015DFR70850).
文摘In this paper,an improved active stabilization strategy of the interface converters in microgrid applications is proposed on the basis of the passivity-based stability criterion(PBSC).As a critical part of AC and DC hybrid microgrids,the DC microgrid is taken as an example.In particular,a stabilization method with a proportional-integral(PI)controller and firstorder high-pass filter(HPF)is proposed to meet the passivity requirements of the overall control diagram with respect to the output voltage.Meanwhile,an output current feedback control loop is introduced to ensure the output impedance passivity.Moreover,a small-signal model of the parallel interface converter system is established to comprehensively study the influence of control parameters on the passivity of the converters.Based on the active stabilization method proposed in this study,by manipulating the control diagram of each interface converter,the passivity and stability of the DC microgrids with variable configuration can be guaranteed.Therefore,a generic and simplified design approach is realized.A simulation model with three interface converters is implemented in MATLAB/Simulink,and the effectiveness of the proposed passivity-based active stabilization algorithm is verified by using this simulation model.
文摘As a growing number of microgrids(MGs)has been integrated into the modern power grids,the interconnection and applicable cooperation among multiple MGs motivate the development of networked MGs.Dynamic MGs,as an advanced networked MGs structure,can not only integrate multiple MGs into the distribution system but also fulfill the requested system network reconfiguration with improved flexibility.A general distributed control approach for networked MGs is reviewed.A distributed control framework for dynamic MGs operation is developed,along with an extensible architecture with considerations of large-scale distributed energy resources(DERs)integration.A scalable small-signal stability analysis is conducted per the proposed distributed control strategies and the conditions under which the system is exponentially stable are derived.At last,the effectiveness of the proposed control framework and stability analysis are verified using a 6-bus test feeder.
