Bifidobacterium longum subsp.infantis is a commensal bacterium that predominates in the infant gut,playing a critical role in both preventing foreign infections and facilitating immune development.This study aimed to ...Bifidobacterium longum subsp.infantis is a commensal bacterium that predominates in the infant gut,playing a critical role in both preventing foreign infections and facilitating immune development.This study aimed to explore the effects of B.longum subsp.infantis supplementation on interferon-beta(IFN-β)secretion and intestinal barrier improvement in growing mice.Female and male mice were orally administered either saline or B.longum subsp.infantis CCFM1269 or I5TI(1×10^(9) CFU/mice per day,n=8)from 1-week-age until 3-,4-,and 5-week-age.RNA sequencing analysis revealed that CCFM1269 exhibited potential antiviral capacity through increasing 2'-5'oligoadenylate synthetase(OAS).Additionally,CCFM1269 supplementation significantly increased colonic IFN-β levels which combined with OAS in 3-week-old female and male mice by activating the TLR4-TRIF-dependent signaling pathway.However,this effect was not observed in 4-and 5-week-old mice.Furthermore,both CCFM1269 were found to modulate the gut microbiota composition and enhance the intestinal barrier function in 3-,4-,and 5-week-old mice.In summary,the results of this study suggested that B.longum subsp.infantis CCFM1269 promoting intestinal barrier and releasing IFN-β in growing mice was in a strain-specific and time-dependent manner.展开更多
Objective:To determine the proportion of imported frozen fish contaminated with Salmonella among retail food stores and supermarkets in the Eastern Province of Saudi Arabia.Methods:A total of 223 frozen freshwater fis...Objective:To determine the proportion of imported frozen fish contaminated with Salmonella among retail food stores and supermarkets in the Eastern Province of Saudi Arabia.Methods:A total of 223 frozen freshwater fish purchased from different supermarkets and grocery stores were analyzed for the presence of foodborne pathogen Salmonella.The isolation of Salmonella was determined and confirmed by using the methods of US Food and Drug Administration's Bacteriological Analytical Manual.CHROMagar Salmonella plus,biochemical tests and API 20E strips.Antimicrobial susceptibilities of Salmonella isolates were determined by the disk diffusion method on Muller-Hinton agar,as described by Kirby-Bauer.in accordance with the guidelines of the Clinical and Laboratory Standards Institute.Results:Out of the total 223 fish samples(20 of catfish,18 of carfu,20 of mirgal,25 of milkfish,35 of mackerel,75 of tilapia,and 30 of rohu),89(39.9%)were tested positive for Salmonella.The prevalence of positive samples were reported for the freshwater fish of pangas(60.0%,n=12),carfu(27.7%,n=5),mirgal(35.0%,n=7),milkfish(52.0%,n=13),mackerel(31.4%,n=11),tilapia imported from Thailand(64.0%,n=16),tilapia imported from India(28.0%,n=14),rohu imported from Thailand(26.6%,n=4)and rohu imported from Myanmar(46.6%,n=7).A total of 140 isolates of Salmonella spp.were yielded from at least seven different types of frozen freshwater fish imported from 5 different countries and were tested for their susceptibility to 16 selected antimicrobial agents.The highest antibiotic resistance was observed to tetracycline(90.71%)followed by ampicillin(70%)and amoxicillin-clavulanic acid(45%).Conclusions:The obtained results of this study shows that these raw retail imported frozen freshwater fish are contaminated with potentially pathogenic Salmonella spp.And the study recommend and suggest that there is a need for adequate consumer measures.展开更多
Protease is wildly used in various fields,such as food,medicine,washing,leather,cosmetics and other industrial fields.In this study,an alkaline protease secreted by Micrococcus NH54PC02 isolated from the South China S...Protease is wildly used in various fields,such as food,medicine,washing,leather,cosmetics and other industrial fields.In this study,an alkaline protease secreted by Micrococcus NH54PC02 isolated from the South China Sea was purified and characterized.The growth curve and enzyme activity curve indicated that the cell reached a maximum concentration at the 30 th hour and the enzyme activity reached the maximum value at the 36 th hour.The protease was purified with 3 steps involving ammonium sulfate precipitation,ion-exchange chromatography and hydrophobic chromatography with 8.22-fold increase in specific activity and 23.68% increase in the recovery.The molecular mass of the protease was estimated to be 25 k Da by SDS-PAGE analysis.The optimum temperature and p H for the protease activity were 50℃ and pH 10.0,respectively.The protease showed a strong stability in a wide range of pH values ranging from 6.0–11.0,and maintained 90% enzyme activity in strong alkaline environment with p H 11.0.Inhibitor trials indicated that the protease might be serine protease.But it also possessed the characteristic of metalloprotease as it could be strongly inhibited by EDTA and strongly stimulated by Mn^(2+).Evaluation of matrix-assisted laser desorption ionization/time-of-flight MS(MALDI-TOF-TOF/MS) showed that the protease might belong to the peptidase S8 family.展开更多
An intense bloom of Karenia sp.was reported in the Oualidia lagoon,part of Atlantic Moroccan coast.The highest concentrations are 1.04×10^7 cells/L,and have been noted at the park station 7.High nutrient concentr...An intense bloom of Karenia sp.was reported in the Oualidia lagoon,part of Atlantic Moroccan coast.The highest concentrations are 1.04×10^7 cells/L,and have been noted at the park station 7.High nutrient concentrations have been observed,and PO4 was the highest value(av.396.18μg/L)recorded at Parc 7.This massive proliferation caused a red tide which extended over 25 km from the Atlantic coast.This event was accompanied by stranding of macroalgae.展开更多
The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combi...The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.展开更多
In this paper,we establish some strong laws of large numbers,which are for nonindependent random variables under the framework of sublinear expectations.One of our main results is for blockwise m-dependent random vari...In this paper,we establish some strong laws of large numbers,which are for nonindependent random variables under the framework of sublinear expectations.One of our main results is for blockwise m-dependent random variables,and another is for sub-orthogonal random variables.Both extend the strong law of large numbers for independent random variables under sublinear expectations to the non-independent case.展开更多
In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses...In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses,some properties and some equivalent characterizations of G_(C)-X-injective modules are investigated,and we also show that the triple(■,cores■,■)is a weak co-AB-context.As an application,two complete cotorsion pairs and a new model structure in Mod S are given.展开更多
In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and...In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants.展开更多
In this paper,we consider the fourth-order parabolic equation with p(x)Laplacian and variable exponent source ut+∆^(2)u−div(|■u|^(p(x)−2■u))=|u|^(q(x))−1u.By applying potential well method,we obtain global existence...In this paper,we consider the fourth-order parabolic equation with p(x)Laplacian and variable exponent source ut+∆^(2)u−div(|■u|^(p(x)−2■u))=|u|^(q(x))−1u.By applying potential well method,we obtain global existence,asymptotic behavior and blow-up of solutions with initial energy J(u_(0))≤d.Moreover,we estimate the upper bound of the blow-up time for J(u_(0))≤0.展开更多
This paper studies certain estimates for the lower bound of distance between unitary orbits of normal elements.We show that the distance between unitary orbits of normal elements of simple C^(*)-algebras of tracial ra...This paper studies certain estimates for the lower bound of distance between unitary orbits of normal elements.We show that the distance between unitary orbits of normal elements of simple C^(*)-algebras of tracial rank no more than k has a lower bound.Furthermore,if k≤1 and normal elements are commuting,then the lower bound will be better.Another result establishes a connection involving the spectrum distance operator Dc between a C^(*)-algebra of stable rank one C^(*)-algebra and its hereditary C^(*)-subalgebra.展开更多
The atom-bond sum-connectivity(ABS)index,put forward by[J.Math.Chem.,2022,60(10):20812093],exhibits a strong link with the acentric factor of octane isomers.The experimental physico-chemical properties of octane isome...The atom-bond sum-connectivity(ABS)index,put forward by[J.Math.Chem.,2022,60(10):20812093],exhibits a strong link with the acentric factor of octane isomers.The experimental physico-chemical properties of octane isomers,such as boiling point,of formation are found to be better measured by the ABS index than by the Randi,atom-bond connectivity(ABC),and sum-connectivity(SC)indices.One important source of information for researching the molecular structure is the bounds for its topological indices.The extrema of the ABS index of the line,total,and Mycielski graphs are calculated in this work.Moreover,the pertinent extremal graphs were illustrated.展开更多
In this paper,we study the generalized Dedekind Rademacher sums considered by Hall,Wilson and Zagier.We establish a new formula for the products of two Bernoulli functions by using Parseval's formula,Hurwitz's...In this paper,we study the generalized Dedekind Rademacher sums considered by Hall,Wilson and Zagier.We establish a new formula for the products of two Bernoulli functions by using Parseval's formula,Hurwitz's formula and Lerch's functional equation.As applications of the result,some well-known reciprocity formulas are deduced as special cases.展开更多
Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied p...Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.展开更多
Let Un be the set of connected unicyclic graphs of order n and girth g.Let C(T_(1),T_(2),...,T_(g))Un be obtained from a cycle v_(1)v_(2)…v_(g)v_(1)(in the anticlockwise direction)by identifying vi with the root of a...Let Un be the set of connected unicyclic graphs of order n and girth g.Let C(T_(1),T_(2),...,T_(g))Un be obtained from a cycle v_(1)v_(2)…v_(g)v_(1)(in the anticlockwise direction)by identifying vi with the root of a rooted tree Ti of order ni for each i=1,2,...,g,where ni≥1 and∑^(g)_(i=1)n_(i)=n.Let S(n_(1),n_(2),...,n_(g))be obtained from C(T_(1),T_(2),..,T_(g))by replacing each Ti by a rooted star Sni with the center as its root.Let U(n_(1),n_(2),...,ng)be the set of unicyclic graphs which differ from the unicyclic graph S(n_(1),n_(2),...,n_(g))only up to a permutation of ni's.In this paper,the graph with the minimal least signless Laplacian eigenvalue(respectively,the graph with maximum signless Laplacian spread)in U(n_(1),n_(2),...,n_(g))is determined.展开更多
Loday introduced di-associative algebras and tri-associative algebras motivated by periodicity phenomena in algebraic K-theory.The purpose of this paper is to study the splittings of operations on di-associative algeb...Loday introduced di-associative algebras and tri-associative algebras motivated by periodicity phenomena in algebraic K-theory.The purpose of this paper is to study the splittings of operations on di-associative algebras and tri-associative algebras.We introduce the notion of a quad-dendriform algebra,which is a splitting of a di-associative algebra.We show that a relative averaging operator on dendriform algebras gives rise to a quad-dendriform algebra.Furthermore,we introduce the notion of six-dendriform algebras,which are splittings of the tri-associative algebras,and demonstrate that homomorphic relative averaging operators induce six-dendriform algebras.展开更多
Let G be a finite group and H a subgroup of G.The normal index of H in G is defined as the order of K/H_(G),where K is a normal supplement of H in G such that|K|is minimal and H_(G)≤K■G.Let p be a prime which divide...Let G be a finite group and H a subgroup of G.The normal index of H in G is defined as the order of K/H_(G),where K is a normal supplement of H in G such that|K|is minimal and H_(G)≤K■G.Let p be a prime which divides the order of a group G.In this paper,some characterizations of G being p-solvable or p-supersolvable were obtained by analyzing the normal index of certain subgroups of G.These results can be viewed as local version of recent results in the literature.展开更多
基金funded by the National Key R&D Program of China(2021YFD2100700)National Natural Science Foundation of China(32021005)+1 种基金111 project(BP0719028)Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province。
文摘Bifidobacterium longum subsp.infantis is a commensal bacterium that predominates in the infant gut,playing a critical role in both preventing foreign infections and facilitating immune development.This study aimed to explore the effects of B.longum subsp.infantis supplementation on interferon-beta(IFN-β)secretion and intestinal barrier improvement in growing mice.Female and male mice were orally administered either saline or B.longum subsp.infantis CCFM1269 or I5TI(1×10^(9) CFU/mice per day,n=8)from 1-week-age until 3-,4-,and 5-week-age.RNA sequencing analysis revealed that CCFM1269 exhibited potential antiviral capacity through increasing 2'-5'oligoadenylate synthetase(OAS).Additionally,CCFM1269 supplementation significantly increased colonic IFN-β levels which combined with OAS in 3-week-old female and male mice by activating the TLR4-TRIF-dependent signaling pathway.However,this effect was not observed in 4-and 5-week-old mice.Furthermore,both CCFM1269 were found to modulate the gut microbiota composition and enhance the intestinal barrier function in 3-,4-,and 5-week-old mice.In summary,the results of this study suggested that B.longum subsp.infantis CCFM1269 promoting intestinal barrier and releasing IFN-β in growing mice was in a strain-specific and time-dependent manner.
基金Supported by the Deanship of Scientific Research,University of Dammam (Grant No.2012139)
文摘Objective:To determine the proportion of imported frozen fish contaminated with Salmonella among retail food stores and supermarkets in the Eastern Province of Saudi Arabia.Methods:A total of 223 frozen freshwater fish purchased from different supermarkets and grocery stores were analyzed for the presence of foodborne pathogen Salmonella.The isolation of Salmonella was determined and confirmed by using the methods of US Food and Drug Administration's Bacteriological Analytical Manual.CHROMagar Salmonella plus,biochemical tests and API 20E strips.Antimicrobial susceptibilities of Salmonella isolates were determined by the disk diffusion method on Muller-Hinton agar,as described by Kirby-Bauer.in accordance with the guidelines of the Clinical and Laboratory Standards Institute.Results:Out of the total 223 fish samples(20 of catfish,18 of carfu,20 of mirgal,25 of milkfish,35 of mackerel,75 of tilapia,and 30 of rohu),89(39.9%)were tested positive for Salmonella.The prevalence of positive samples were reported for the freshwater fish of pangas(60.0%,n=12),carfu(27.7%,n=5),mirgal(35.0%,n=7),milkfish(52.0%,n=13),mackerel(31.4%,n=11),tilapia imported from Thailand(64.0%,n=16),tilapia imported from India(28.0%,n=14),rohu imported from Thailand(26.6%,n=4)and rohu imported from Myanmar(46.6%,n=7).A total of 140 isolates of Salmonella spp.were yielded from at least seven different types of frozen freshwater fish imported from 5 different countries and were tested for their susceptibility to 16 selected antimicrobial agents.The highest antibiotic resistance was observed to tetracycline(90.71%)followed by ampicillin(70%)and amoxicillin-clavulanic acid(45%).Conclusions:The obtained results of this study shows that these raw retail imported frozen freshwater fish are contaminated with potentially pathogenic Salmonella spp.And the study recommend and suggest that there is a need for adequate consumer measures.
基金supported by the Fundamental Research Funds for the Central Universities(No.201564018)Qingdao Shinan District Science and Technology Development Funds(No.2014-14-002-SW)+1 种基金Major Special Science and Technology Projects in Shandong Province(No.2015ZDZX05003)the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers(No.U1406402)
文摘Protease is wildly used in various fields,such as food,medicine,washing,leather,cosmetics and other industrial fields.In this study,an alkaline protease secreted by Micrococcus NH54PC02 isolated from the South China Sea was purified and characterized.The growth curve and enzyme activity curve indicated that the cell reached a maximum concentration at the 30 th hour and the enzyme activity reached the maximum value at the 36 th hour.The protease was purified with 3 steps involving ammonium sulfate precipitation,ion-exchange chromatography and hydrophobic chromatography with 8.22-fold increase in specific activity and 23.68% increase in the recovery.The molecular mass of the protease was estimated to be 25 k Da by SDS-PAGE analysis.The optimum temperature and p H for the protease activity were 50℃ and pH 10.0,respectively.The protease showed a strong stability in a wide range of pH values ranging from 6.0–11.0,and maintained 90% enzyme activity in strong alkaline environment with p H 11.0.Inhibitor trials indicated that the protease might be serine protease.But it also possessed the characteristic of metalloprotease as it could be strongly inhibited by EDTA and strongly stimulated by Mn^(2+).Evaluation of matrix-assisted laser desorption ionization/time-of-flight MS(MALDI-TOF-TOF/MS) showed that the protease might belong to the peptidase S8 family.
文摘An intense bloom of Karenia sp.was reported in the Oualidia lagoon,part of Atlantic Moroccan coast.The highest concentrations are 1.04×10^7 cells/L,and have been noted at the park station 7.High nutrient concentrations have been observed,and PO4 was the highest value(av.396.18μg/L)recorded at Parc 7.This massive proliferation caused a red tide which extended over 25 km from the Atlantic coast.This event was accompanied by stranding of macroalgae.
基金Guangzhou Metro Scientific Research Project(No.JT204-100111-23001)Chongqing Municipal Special Project for Technological Innovation and Application Development(No.CSTB2022TIAD-KPX0101)Science and Technology Research and Development Program of China State Railway Group Co.,Ltd.(No.N2023G045)。
文摘The uplift resistance of the soil overlying shield tunnels significantly impacts their anti-floating stability.However,research on uplift resistance concerning special-shaped shield tunnels is limited.This study combines numerical simulation with machine learning techniques to explore this issue.It presents a summary of special-shaped tunnel geometries and introduces a shape coefficient.Through the finite element software,Plaxis3D,the study simulates six key parameters—shape coefficient,burial depth ratio,tunnel’s longest horizontal length,internal friction angle,cohesion,and soil submerged bulk density—that impact uplift resistance across different conditions.Employing XGBoost and ANN methods,the feature importance of each parameter was analyzed based on the numerical simulation results.The findings demonstrate that a tunnel shape more closely resembling a circle leads to reduced uplift resistance in the overlying soil,whereas other parameters exhibit the contrary effects.Furthermore,the study reveals a diminishing trend in the feature importance of buried depth ratio,internal friction angle,tunnel longest horizontal length,cohesion,soil submerged bulk density,and shape coefficient in influencing uplift resistance.
文摘In this paper,we establish some strong laws of large numbers,which are for nonindependent random variables under the framework of sublinear expectations.One of our main results is for blockwise m-dependent random variables,and another is for sub-orthogonal random variables.Both extend the strong law of large numbers for independent random variables under sublinear expectations to the non-independent case.
文摘In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses,some properties and some equivalent characterizations of G_(C)-X-injective modules are investigated,and we also show that the triple(■,cores■,■)is a weak co-AB-context.As an application,two complete cotorsion pairs and a new model structure in Mod S are given.
文摘In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants.
基金Supported by NSFC(No.12101482)the Natural Science Foundation of Shaanxi Province,China(No.2018JQ1052)。
文摘In this paper,we consider the fourth-order parabolic equation with p(x)Laplacian and variable exponent source ut+∆^(2)u−div(|■u|^(p(x)−2■u))=|u|^(q(x))−1u.By applying potential well method,we obtain global existence,asymptotic behavior and blow-up of solutions with initial energy J(u_(0))≤d.Moreover,we estimate the upper bound of the blow-up time for J(u_(0))≤0.
基金Supported by Zhejiang Provincial Natural Science Foundation of China(No.ZCLQN25A0103)。
文摘This paper studies certain estimates for the lower bound of distance between unitary orbits of normal elements.We show that the distance between unitary orbits of normal elements of simple C^(*)-algebras of tracial rank no more than k has a lower bound.Furthermore,if k≤1 and normal elements are commuting,then the lower bound will be better.Another result establishes a connection involving the spectrum distance operator Dc between a C^(*)-algebra of stable rank one C^(*)-algebra and its hereditary C^(*)-subalgebra.
基金Supported by Ningbo NSF(No.2021J234)Zhejiang Provincial Philosophy and Social Sciences Planning Project(No.24NDJC057YB)。
文摘The atom-bond sum-connectivity(ABS)index,put forward by[J.Math.Chem.,2022,60(10):20812093],exhibits a strong link with the acentric factor of octane isomers.The experimental physico-chemical properties of octane isomers,such as boiling point,of formation are found to be better measured by the ABS index than by the Randi,atom-bond connectivity(ABC),and sum-connectivity(SC)indices.One important source of information for researching the molecular structure is the bounds for its topological indices.The extrema of the ABS index of the line,total,and Mycielski graphs are calculated in this work.Moreover,the pertinent extremal graphs were illustrated.
基金Supported by the Natural Science Foundation of Sichuan Province(No.2023NSFSC0065)。
文摘In this paper,we study the generalized Dedekind Rademacher sums considered by Hall,Wilson and Zagier.We establish a new formula for the products of two Bernoulli functions by using Parseval's formula,Hurwitz's formula and Lerch's functional equation.As applications of the result,some well-known reciprocity formulas are deduced as special cases.
基金supported by grants from the Natural Science Foundation of China(22362031 and 21805121)the Science and Technology Project of Yunnan Province(2019FD137)。
文摘Proton exchange membrane fuel cells(PEMFCs)are considered as a promising renewable power source.However,the massive commercial application of PEMFCs has been greatly hindered by their high expense and less-satisfied performance mainly due to the sluggish oxygen reduction reaction(ORR)kinetics even on state-of-the-art Pt catalyst.Octahedral PtNi nanoparticles(oct-PtNi NPs)with excellent ORR activity in a half-cell have been widely studied,while their performance in membrane electrode assembly(MEA)has much less reported.Herein,we investigated the MEA performance using the carbon supported oct-PtNi NPs(oct-PtNi/C)as the cathode catalyst.Under the mild acid washing condition,the surface Ni atoms of oct-PtNi/C were largely removed,and the performance of the MEA using the acid-leaching oct-PtNi/C(PNC-A)as the cathode catalyst was greatly improved.The maximum power density of the MEA reached 1.0 W·cm^(-2) with the cath-ode Pt loading of 0.2 mg·cm^(-2),which is 15%higher than that using Pt/C as the catalyst.After 30k cycles in the accelerated degradation test(ADT),the MEA using PNC-A as the catalyst showed a performance retention of 82%,higher than that of Pt/C(74%).The results reported here verify the possibility of using PNC-A as an advanced cathode catalyst in PEMFCs,thus enhancing the performance of PEMFCs while lowering the amount of expensive Pt.
基金This research is supported by NSFC(Nos.12171154,12301438)the Chenguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.23CGA37)。
文摘Let Un be the set of connected unicyclic graphs of order n and girth g.Let C(T_(1),T_(2),...,T_(g))Un be obtained from a cycle v_(1)v_(2)…v_(g)v_(1)(in the anticlockwise direction)by identifying vi with the root of a rooted tree Ti of order ni for each i=1,2,...,g,where ni≥1 and∑^(g)_(i=1)n_(i)=n.Let S(n_(1),n_(2),...,n_(g))be obtained from C(T_(1),T_(2),..,T_(g))by replacing each Ti by a rooted star Sni with the center as its root.Let U(n_(1),n_(2),...,ng)be the set of unicyclic graphs which differ from the unicyclic graph S(n_(1),n_(2),...,n_(g))only up to a permutation of ni's.In this paper,the graph with the minimal least signless Laplacian eigenvalue(respectively,the graph with maximum signless Laplacian spread)in U(n_(1),n_(2),...,n_(g))is determined.
基金Supported by the Science and Technology Program of Guizhou Province(Grant No.QKHJC QN[2025]362)the National Natural Science Foundation of China(Grant No.12361005).
文摘Loday introduced di-associative algebras and tri-associative algebras motivated by periodicity phenomena in algebraic K-theory.The purpose of this paper is to study the splittings of operations on di-associative algebras and tri-associative algebras.We introduce the notion of a quad-dendriform algebra,which is a splitting of a di-associative algebra.We show that a relative averaging operator on dendriform algebras gives rise to a quad-dendriform algebra.Furthermore,we introduce the notion of six-dendriform algebras,which are splittings of the tri-associative algebras,and demonstrate that homomorphic relative averaging operators induce six-dendriform algebras.
基金Supported by the National Natural Science Foundation of China(Grant No.12071092)Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515012072)+1 种基金the Natural Science Research Project of Anhui Educational Committee(Grant No.2024AH051298)the Scientific Research Foundation of Bozhou University(Grant No.BYKQ202419).
文摘Let G be a finite group and H a subgroup of G.The normal index of H in G is defined as the order of K/H_(G),where K is a normal supplement of H in G such that|K|is minimal and H_(G)≤K■G.Let p be a prime which divides the order of a group G.In this paper,some characterizations of G being p-solvable or p-supersolvable were obtained by analyzing the normal index of certain subgroups of G.These results can be viewed as local version of recent results in the literature.
