The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evi...The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.展开更多
Initial success has been achieved in Hong Kong in controlling primary air pollutants,but ambient ozone levels kept increasing during the past three decades.Volatile organic compounds(VOCs)are important for mitigating ...Initial success has been achieved in Hong Kong in controlling primary air pollutants,but ambient ozone levels kept increasing during the past three decades.Volatile organic compounds(VOCs)are important for mitigating ozone pollution as its major precursors.This study analyzed VOC characteristics of roadside,suburban,and rural sites in Hong Kong to investigate their compositions,concentrations,and source contributions.Herewe showthat the TVOC concentrations were 23.05±13.24,12.68±15.36,and 5.16±5.48 ppbv for roadside,suburban,and rural sites between May 2015 to June 2019,respectively.By using Positive Matrix Factorization(PMF)model,six sources were identified at the roadside site over five years:Liquefied petroleum gas(LPG)usage(33%–46%),gasoline evaporation(8%–31%),aged air mass(11%–28%),gasoline exhaust(5%–16%),diesel exhaust(2%–16%)and fuel filling(75–9%).Similarly,six sources were distinguished at the suburban site,including LPG usage(30%–33%),solvent usage(20%–26%),diesel exhaust(14%–26%),gasoline evaporation(8%–16%),aged air mass(4%–11%),and biogenic emissions(2%–5%).At the rural site,four sources were identified,including aged airmass(33%–51%),solvent usage(25%–30%),vehicular emissions(11%–28%),and biogenic emissions(6%–12%).The analysis further revealed that fuel filling and LPG usage were the primary contributors to OFP and OH reactivity at the roadside site,while solvent usage and biogenic emissions accounted for almost half of OFP and OH reactivity at the suburban and rural sites,respectively.These findings highlight the importance of identifying and characterizing VOC sources at different sites to help policymakers develop targeted measures for pollution mitigation in specific areas.展开更多
To explore the potential utilization of Elaeagnus mollis,we conducted a comprehensive assessment of its phytochemical composition,antioxidant properties,cholinesterase inhibition,and anti-HepG2 cell proliferation acti...To explore the potential utilization of Elaeagnus mollis,we conducted a comprehensive assessment of its phytochemical composition,antioxidant properties,cholinesterase inhibition,and anti-HepG2 cell proliferation activity across different plant parts(branch wood,branch bark,and pericarp)using various solvents(water,methanol,ethanol,and n-hexane).Our findings revealed that water extracts displayed superior antioxidant activities in ABTS and RP assays,while methanol extracts exhibited better performance in DPPH and FRAP assays.Moreover,methanol extracts demonstrated the highest effectiveness against anti-HepG2 cell proliferation,whereas n-hexane extracts showed greater efficiency in cholinesterase inhibition.Notably,branch bark extracts exhibited the highest levels of phytochemical compounds,with both branch bark and pericarp extracts demonstrating significant effects in cholinesterase inhibition and anti-HepG2 cell proliferation.Correlation analysis indicated that phytochemical compounds were primarily responsible for the observed biological activities.Overall,extracts from the branch bark and pericarp of E.mollis showed promising potential for antioxidant and anticancer activities,suggesting their suitability for applications in the pharmaceutical industry as health-promoting products.展开更多
Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to ...Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to the inevitable side reactions involving cycloaddition.Herein,the visible-light-mediated O-H functionalization reactions of alkenyl alcohols with diazo compounds were developed.This process competed favorably with the cycloaddition reaction.A series of multifunctional ethers were provided in low to high yields with aryldiazoacetates or 3-diazooxindoles.Biologically relevant spirooxindole-fused oxacycle could be easily accessed from the O-H functionalization product of alkenyl alcohol and 3-diazooxindole.展开更多
The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic comp...The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.展开更多
Employing the principle of active moiety concatenation, a novel series of symmetrical triazine compounds were designed. A series of novel triazine compounds were synthesized using cyanuric chloride, amines, and chalco...Employing the principle of active moiety concatenation, a novel series of symmetrical triazine compounds were designed. A series of novel triazine compounds were synthesized using cyanuric chloride, amines, and chalcones as the initial reactants. The structures of these compounds were characterized through FT-IR, 1H-NMR, 13C-NMR, high-resolution mass spectrometry (HRMS) and high performance liquid chromatography (HPLC). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetra- zolium bromide (MTT) assay was employed to evaluate the in vitro anti-proliferative activity of the new s-triazine compounds against human lung cancer cells (A549), human cervical cancer cells (HeLa), human breast cancer cells (MCF-7) and human colon cancer cells (SW620). The findings indicated that several compounds exhibited promising antitumor effects. Notably, (E)-1-(4-((4,6-dimorpholino-1,3,5-triazin-2-yl)oxy)phenyl)-3-(thiophen-2-yl)prop-2-en-1-one (3bg) demonstrated efficacy as a broad-spectrum anticancer agent, exhibiting significant activity against the A549, HeLa, and MCF-7 cell lines. Furthermore, (E)-1-(4-((4,6-dimorpholino-1,3,5-triazin-2-yl)oxy)phenyl)-3-phenylprop-2-en-1-one (3bb) displayed the most potent in vitro antitumor activity against the MCF-7 cell line with an IC_(50) value of 16.4 μmol/L, establishing it as the most active compound in assay.展开更多
Direct enantioselective allylic C—H functionalization has emerged as a powerful strategy for the asymmetric syn-thesis of highly valuable chiral products.Herein,a Rh(III)-catalyzed enantioselective allylic C—H alkyl...Direct enantioselective allylic C—H functionalization has emerged as a powerful strategy for the asymmetric syn-thesis of highly valuable chiral products.Herein,a Rh(III)-catalyzed enantioselective allylic C—H alkylation of unactivated alkenes withα-diazo carbonyl compounds is described,enabling direct access to chiral products with high efficiency(up to 77%yield,92%ee,and>10∶1 B/L(branched/linear)selectivity).This atom-and step-economical protocol directly converts simple,unactivated substrates into valuable enantioenriched products under mild conditions,providing an efficient catalytic system for asymmetric allylic C—H functionalization.展开更多
Breast cancer(BC)is one of the most prevalent malignant tumors affecting women worldwide,with its incidence rate continuously increasing.As a result,treatment strategies for this disease have received considerable att...Breast cancer(BC)is one of the most prevalent malignant tumors affecting women worldwide,with its incidence rate continuously increasing.As a result,treatment strategies for this disease have received considerable attention.Research has highlighted the crucial role of the Hedgehog(Hh)signaling pathway in the initiation and progression of BC,particularly in promoting tumor growth and metastasis.Therefore,molecular targets within this pathway represent promising opportunities for the development of novel BC therapies.This study aims to elucidate the therapeutic mechanisms by which natural compounds modulate the Hh signaling pathway in BC.By conducting a comprehensive review of various natural compounds,including polyphenols,terpenes,and alkaloids,we reveal both common and unique regulatory mechanisms that influence this pathway.This investigation represents the first comprehensive analysis of five distinct mechanisms through which natural compounds modulate key molecules within the Hh pathway and their impact on the aggressive behaviors of BC.Furthermore,by exploring the structure-activity relationships between these compounds and their molecular targets,we shed light on the specific structural features that enable natural compounds to interact with various components of the Hh pathway.These novel insights contribute to advancing the development and clinical application of natural compound-based therapeutics.Our thorough review not only lays the groundwork for exploring innovative BC treatments but also opens new avenues for leveraging natural compounds in cancer therapy.展开更多
Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study...Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.展开更多
Existing evidence has demonstrated the association between exposure to volatile organic compounds(VOCs)and osteoporosis(OP)risk,but the underlying mechanistic framework remains unclear.This study aimed to explore pote...Existing evidence has demonstrated the association between exposure to volatile organic compounds(VOCs)and osteoporosis(OP)risk,but the underlying mechanistic framework remains unclear.This study aimed to explore potential pathways using adverse outcome pathway(AOP)analysis,and evidence this association in middle-to-old-aged American adults using the updated National Health and Nutrition Examination Survey data.Multivariable-adjusted general linear and weighted quantile sum models were employed to analyze associations of VOC metabolites(VOCMs),representing internal VOCs exposure levels,with OP-related phenotypes.An AOP framework based on network analysis was developed by extracting target genes and phenotypes.Among 3555 American adults aged≥40 years(539 OP participants),we found that increasing urinary 3-and 4-methylhippuric acid,N-acetyl-S-(n-propyl)-l-cysteine(BPMA),and N-acetyl-S-(3-hydroxypropyl)-l-cysteine were associated with elevated OP odds with odds ratios(ORs)(95%confidence intervals,95%CIs)being 1.254(1.016 to 1.548),1.182(1.014 to 1.377),and 1.244(1.029 to 1.505),respectively,per standard deviation.Urinary BPMA and N-acetyl-S-(2-cyanoethyl)-l-cysteine were inversely associated with lumbar spine bone mineral density(BMD),while urinary N-acetyl-S-(2-hydroxypropyl)-l-cysteine was positively associated with hip BMD.Additionally,OP odds increased by 46.0%(95%CI:3.9%to 105.1%)per quartile increment in the VOC mixture.AOP analysis identified 53 target genes and 9 target phenotypes,and 5 of 9 target phenotypes were oxidative stress(OS)-related.Literature and the“AOP 482”framework implied the core role of OS in the VOC exposure and prevalent OP association,with the interleukin-6 as themolecular initiating event.Our findings provided a theoretical basis for further investigation.展开更多
Achieving sustainable energy and chemical production has become an important issue for human society.Photocatalysis has attracted much attention due to its ability to harness solar energy to drive chemical reactions.M...Achieving sustainable energy and chemical production has become an important issue for human society.Photocatalysis has attracted much attention due to its ability to harness solar energy to drive chemical reactions.Metal sulfide-based photocatalysts(e.g.,Cd S,Zn In2S4)have shown substantial potential in biomass-based hydroxyl compound valorization.In this review,we summarize the recent progress in metal sulfide-based photocatalysts for the photo upgrading of biomass-derived hydroxyl compounds coupled with reduction reactions(e.g.,CO_(2)reduction,H_(2)O_(2)generation,and H_(2)evolution).The mechanism of biomass redox reactions is discussed,highlighting the potential of realizing the valorization of biomass-derived compounds coupled with the reduction reactions,which is beneficial for researchers to actively explore biomass biorefinery pathways in order to modulate the selectivity of the valueadded products.Various modification strategies are presented,including elemental doping,defect engineering,heterojunction construction,and cocatalyst loading.These strategies modulate the energy band structure,surface electron density,and built-in electric field strength of metal sulfide-based photocatalysts,thereby enhancing their photocatalytic performance.The challenges and prospects of metal sulfidebased photocatalysts in biomass valorization are analyzed.This approach contributes to the development of photocatalysts that can accelerate biomass photo-upgrading coupling reactions.This review aims to provide deeper insights into the photocatalytic biorefinery pathways and contribute to the development of functionalized photocatalysts that can accelerate biomass photo upgrading,highlighting the synergistic effects of multiple coupling reactions.展开更多
The associations of volatile organic compounds(VOCs)exposure with short sleep duration(SSD)have rarely been studied.We aimed to evaluate the correlation between VOC exposure and SSD risk,while also exploring the poten...The associations of volatile organic compounds(VOCs)exposure with short sleep duration(SSD)have rarely been studied.We aimed to evaluate the correlation between VOC exposure and SSD risk,while also exploring the potential mediating influence of depressive symptoms.Blood concentrations of seven VOCs,namely benzene,toluene,ethylbenzene,m-/p-xylene,o-xylene,styrene(collectively known as BTEXS),and 1,4-dichlorobenzene,were analyzed in 2905 U.S.adults.Weighted logistic regression,quantile-based g-computation(QGC),and weighted quantile sum(WQS)regression were employed to investigate associations between selected VOCs and SSD risk.Mediation analyses were conducted to explore the potential mediating effects of depressive symptoms on these relationships.Increased blood levels of BTEXS were positively correlated with SSD risk,with odds ratios(OR)ranging from 1.130 to 1.212(all P<0.05).A nonlinear association between toluene concentration and SSD risk was observed(P for nonlinearity=0.028).Both QGC and WQS analyses indicated a positive association between co-exposure to VOCs and SSD,with styrene showing the highest positive weights(QGC:OR=1.313,95%confidence interval(CI):1.038–1.660;WQS:OR=1.386,95%CI:1.111–1.731).Furthermore,BTEXS exposure was positively linked to depressive symptoms,which in turn were significantly associated with SSD risk.Mediation analyses revealed that depressive symptoms partially mediated the relationships between individual and mixed VOCs and SSD risk,with mediation proportions ranging from 15.87%to 20.54%(all P<0.05).These findings indicated that exposure to VOCs increased SSD risk,with depressive symptoms playing a partial mediating role.展开更多
The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and A...The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and Al_(3)Ni brittle intermetallic compounds(IMCs)under different conditions was investigated,and the formation mechanisms of dendritic Al_(3)Ni crystals with different morphologies were elucidated.The increasing remelting cycles accelerated the formation of Al_(3)Ni_(2) layer and the growth of Al_(3)Ni IMCs.The increased-step heating temperatures and time promoted the morphological transition from faceted to non-faceted dendritic Al_(3)Ni,which was attributed to the enhanced undercooling during solidification and incompletely remelted Al_(3)Ni IMCs during remelting.The growth of regular Al_(3)Ni dendrites was dominated by coalescence of secondary dendrite arms,while the growth of irregular dendrites Al_(3)Ni was controlled by dendrite merging,radial melting and axial melting of secondary arms.The axially free dendritic Al_(3)Ni was attributed to the small distance between adjacent main trunks,and the dense secondary arms promoted the formation of local solute depletion regions.展开更多
Wide bandgap semiconductors are typically activated under ultraviolet(UV)light irradiation for volatile organic compounds(VOCs)degradation.However,our previous study discovered that certain VOCs can interact with some...Wide bandgap semiconductors are typically activated under ultraviolet(UV)light irradiation for volatile organic compounds(VOCs)degradation.However,our previous study discovered that certain VOCs can interact with some wide bandgap semiconductors,formatting an intermediate bandgap between the VOCs and the conduction band of wide bandgap semiconductor,thus inducing visible light activation of the system,and photo-generated electrons are excited by visible light and transferred from the VOCs to the conduction band of semiconductor.In this work,BaTiO_(3),traditionally is not active under visible light irradiation,however showed degradation rates of 100%and 20%for styrene and toluene under visible light,respectively.Density functional theory(DFT)calculations indicate that the adsorption of styrene or toluene on the BaTiO_(3)surface reduces its bandgap from 2.93 eV to 1.36 eV and 2.26 eV,respectively.The intermediate bandgap in this system is primarily formed by the valence band of BaTiO_(3)and the VOCs,and indicating that photo-generated electrons directly transfer from BaTiO_(3)to the VOCs under visible light,inducing degradation reactions of VOCs,i.e.,this work discovered a new transfer pathway of photo-electrons direct from the valence band of BaTiO_(3)to VOCs,while photo-electrons are from VOCs to the conductive band of wide-bandgap semiconductors in our previous work.展开更多
The presence of residual alkaline compounds in the ultrahigh-nickel layered oxide cathodes(LiNi_(x)Co_(y)Mn_(1−x−y)O_(2),x≥_(0.9))aggravates structural degradation,increases surface reactivity,and promotes slurry gel...The presence of residual alkaline compounds in the ultrahigh-nickel layered oxide cathodes(LiNi_(x)Co_(y)Mn_(1−x−y)O_(2),x≥_(0.9))aggravates structural degradation,increases surface reactivity,and promotes slurry gelation,leading to the capacity decay of batteries with these cathodes and complicating their manufacturing.Traditional approaches for addressing this issue,including direct removal,coverage,and utilization,are complex and require surface regeneration.Herein,we propose neutralizing residual alkaline compounds with 3-thiopheneboronic acid(3-TBA)to improve the performance of LiNi_(0.9)5Co_(0.04)Mn_(0.01)O_(2)(NCM)cathode material,a facile strategy that does not require any post-treatment.The suggested reaction yields a uniform and thin organic-modified layer on the surface of the NCM cathode,improving its chemical stability toward the electrolyte,as demonstrated by multiple characterization methods.The modified NCM cathode exhibited impressive cyclic and rate performances,achieving a capacity retention of 83.34%after 200 cycles at 1.0 C and a specific capacity of 162.00 mAh·g^(−1) at 10.0 C.Most importantly,the proposed approach can efficiently suppress unfavorable phase transitions,severe electrolyte degradation,and CO_(2) gas evolution,improving the application potential of ultrahigh-nickel layered oxide cathode materials.展开更多
Substantial effects of photochemical reaction losses of volatile organic compounds(VOCs)on factor profiles can be investigated by comparing the differences between daytime and nighttime dispersion-normalized VOC data ...Substantial effects of photochemical reaction losses of volatile organic compounds(VOCs)on factor profiles can be investigated by comparing the differences between daytime and nighttime dispersion-normalized VOC data resolved profiles.Hourly speciated VOC data measured in Shijiazhuang,China from May to September 2021 were used to conduct study.The mean VOC concentration in the daytime and at nighttime were 32.8 and 36.0 ppbv,respectively.Alkanes and aromatics concentrations in the daytime(12.9 and 3.08 ppbv)were lower than nighttime(15.5 and 3.63 ppbv),whereas that of alkenes showed the opposite tendency.The concentration differences between daytime and nighttime for alkynes and halogenated hydrocarbonswere uniformly small.The reactivities of the dominant species in factor profiles for gasoline emissions,natural gas and diesel vehicles,and liquefied petroleum gas were relatively low and their profiles were less affected by photochemical losses.Photochemical losses produced a substantial impact on the profiles of solvent use,petrochemical industry emissions,combustion sources,and biogenic emissions where the dominant species in these factor profiles had high reactivities.Although the profile of biogenic emissions was substantially affected by photochemical loss of isoprene,the low emissions at nighttime also had an important impact on its profile.Chemical losses of highly active VOC species substantially reduced their concentrations in apportioned factor profiles.This study results were consistent with the analytical results obtained through initial concentration estimation,suggesting that the initial concentration estimation could be the most effective currently availablemethod for the source analyses of active VOCs although with uncertainty.展开更多
The disconnection between teaching,learning,and evaluation is particularly pronounced in traditional high school chemistry teaching.To align with the demands of the new curriculum standards for talent development,it i...The disconnection between teaching,learning,and evaluation is particularly pronounced in traditional high school chemistry teaching.To align with the demands of the new curriculum standards for talent development,it is essential to implement reforms and innovations in teaching methods.This paper initially elucidates the integrated concept of teaching,learning,and evaluation,as well as its practical significance in the classroom.Subsequently,it explores the effective teaching design centered on the theme of iron and its compounds,actively investigating the implementation approach of the integration principle of teaching,learning,and evaluation in classroom.Furthermore,the paper emphasizes the pivotal role of the evaluation part in fostering the professional development of teachers and enhancing the core competencies of students,ultimately aiming to achieve high efficiency and quality in chemistry classroom teaching.展开更多
Carbonyl compounds are abundant in nature and represent a substantial portion of biomass resources.Despite significant recent progress in homo-coupling of carbonyl compounds,achieving their deoxyfunctionalization homo...Carbonyl compounds are abundant in nature and represent a substantial portion of biomass resources.Despite significant recent progress in homo-coupling of carbonyl compounds,achieving their deoxyfunctionalization homo-coupling remains a highly intricate challenge.Herein,we report an entirely novel reaction paradigm:the trifluoromethylative homo-coupling of carbonyl compounds via hydrazones,which enables the formation of three C(sp^(3))-C(sp^(3))bonds in a single step.This method provides a new pathway for synthesizing trifluoromethylative coupling product which has unique applications in both fields of medical and material sciences.Mechanistic investigations have unveiled that the formation of a trifluoromethyl-substituted benzyl radical plays a pivotal role as a key intermediate in this reaction.展开更多
基金supported by the National Natural Science Foundation of China(52301240,52472274)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK259909299001-022)。
文摘The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.
基金supported by Hong Kong Environment Protection Department(Quotation Ref.18-06532)Hong Kong Innovation and Technology Fund(ITS/193/20FP)Hong Kong Research Grants Council(No.26304921).
文摘Initial success has been achieved in Hong Kong in controlling primary air pollutants,but ambient ozone levels kept increasing during the past three decades.Volatile organic compounds(VOCs)are important for mitigating ozone pollution as its major precursors.This study analyzed VOC characteristics of roadside,suburban,and rural sites in Hong Kong to investigate their compositions,concentrations,and source contributions.Herewe showthat the TVOC concentrations were 23.05±13.24,12.68±15.36,and 5.16±5.48 ppbv for roadside,suburban,and rural sites between May 2015 to June 2019,respectively.By using Positive Matrix Factorization(PMF)model,six sources were identified at the roadside site over five years:Liquefied petroleum gas(LPG)usage(33%–46%),gasoline evaporation(8%–31%),aged air mass(11%–28%),gasoline exhaust(5%–16%),diesel exhaust(2%–16%)and fuel filling(75–9%).Similarly,six sources were distinguished at the suburban site,including LPG usage(30%–33%),solvent usage(20%–26%),diesel exhaust(14%–26%),gasoline evaporation(8%–16%),aged air mass(4%–11%),and biogenic emissions(2%–5%).At the rural site,four sources were identified,including aged airmass(33%–51%),solvent usage(25%–30%),vehicular emissions(11%–28%),and biogenic emissions(6%–12%).The analysis further revealed that fuel filling and LPG usage were the primary contributors to OFP and OH reactivity at the roadside site,while solvent usage and biogenic emissions accounted for almost half of OFP and OH reactivity at the suburban and rural sites,respectively.These findings highlight the importance of identifying and characterizing VOC sources at different sites to help policymakers develop targeted measures for pollution mitigation in specific areas.
基金National Natural Science Foundation of China(Grant No.31600549).
文摘To explore the potential utilization of Elaeagnus mollis,we conducted a comprehensive assessment of its phytochemical composition,antioxidant properties,cholinesterase inhibition,and anti-HepG2 cell proliferation activity across different plant parts(branch wood,branch bark,and pericarp)using various solvents(water,methanol,ethanol,and n-hexane).Our findings revealed that water extracts displayed superior antioxidant activities in ABTS and RP assays,while methanol extracts exhibited better performance in DPPH and FRAP assays.Moreover,methanol extracts demonstrated the highest effectiveness against anti-HepG2 cell proliferation,whereas n-hexane extracts showed greater efficiency in cholinesterase inhibition.Notably,branch bark extracts exhibited the highest levels of phytochemical compounds,with both branch bark and pericarp extracts demonstrating significant effects in cholinesterase inhibition and anti-HepG2 cell proliferation.Correlation analysis indicated that phytochemical compounds were primarily responsible for the observed biological activities.Overall,extracts from the branch bark and pericarp of E.mollis showed promising potential for antioxidant and anticancer activities,suggesting their suitability for applications in the pharmaceutical industry as health-promoting products.
文摘Visible-light-mediated O-H functionalization reactions of alcohols with diazo compounds have been fully developed in recent years.However,alkenyl and acetylenic alcohols were rarely examined in these reactions due to the inevitable side reactions involving cycloaddition.Herein,the visible-light-mediated O-H functionalization reactions of alkenyl alcohols with diazo compounds were developed.This process competed favorably with the cycloaddition reaction.A series of multifunctional ethers were provided in low to high yields with aryldiazoacetates or 3-diazooxindoles.Biologically relevant spirooxindole-fused oxacycle could be easily accessed from the O-H functionalization product of alkenyl alcohol and 3-diazooxindole.
文摘The Rh(III)-catalyzed C—H functionalization of sulfoxonium ylides and successively annulation with two classes of cyclic diazo compounds has been realized,affording structurally diverse fused-ring or spirocyclic compounds under redoxneutral conditions.The reaction proceeds via successive chelation-assisted C—H activation,carbene insertion,and intramolecular[3+3]/[4+1]annulation processes.
文摘Employing the principle of active moiety concatenation, a novel series of symmetrical triazine compounds were designed. A series of novel triazine compounds were synthesized using cyanuric chloride, amines, and chalcones as the initial reactants. The structures of these compounds were characterized through FT-IR, 1H-NMR, 13C-NMR, high-resolution mass spectrometry (HRMS) and high performance liquid chromatography (HPLC). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetra- zolium bromide (MTT) assay was employed to evaluate the in vitro anti-proliferative activity of the new s-triazine compounds against human lung cancer cells (A549), human cervical cancer cells (HeLa), human breast cancer cells (MCF-7) and human colon cancer cells (SW620). The findings indicated that several compounds exhibited promising antitumor effects. Notably, (E)-1-(4-((4,6-dimorpholino-1,3,5-triazin-2-yl)oxy)phenyl)-3-(thiophen-2-yl)prop-2-en-1-one (3bg) demonstrated efficacy as a broad-spectrum anticancer agent, exhibiting significant activity against the A549, HeLa, and MCF-7 cell lines. Furthermore, (E)-1-(4-((4,6-dimorpholino-1,3,5-triazin-2-yl)oxy)phenyl)-3-phenylprop-2-en-1-one (3bb) displayed the most potent in vitro antitumor activity against the MCF-7 cell line with an IC_(50) value of 16.4 μmol/L, establishing it as the most active compound in assay.
文摘Direct enantioselective allylic C—H functionalization has emerged as a powerful strategy for the asymmetric syn-thesis of highly valuable chiral products.Herein,a Rh(III)-catalyzed enantioselective allylic C—H alkylation of unactivated alkenes withα-diazo carbonyl compounds is described,enabling direct access to chiral products with high efficiency(up to 77%yield,92%ee,and>10∶1 B/L(branched/linear)selectivity).This atom-and step-economical protocol directly converts simple,unactivated substrates into valuable enantioenriched products under mild conditions,providing an efficient catalytic system for asymmetric allylic C—H functionalization.
基金supported by the National Natural Science Foundation of China(Grant No.:82174222)Shandong Province Natural Science Foundation,China(Grant No.:ZR2021LZY015).
文摘Breast cancer(BC)is one of the most prevalent malignant tumors affecting women worldwide,with its incidence rate continuously increasing.As a result,treatment strategies for this disease have received considerable attention.Research has highlighted the crucial role of the Hedgehog(Hh)signaling pathway in the initiation and progression of BC,particularly in promoting tumor growth and metastasis.Therefore,molecular targets within this pathway represent promising opportunities for the development of novel BC therapies.This study aims to elucidate the therapeutic mechanisms by which natural compounds modulate the Hh signaling pathway in BC.By conducting a comprehensive review of various natural compounds,including polyphenols,terpenes,and alkaloids,we reveal both common and unique regulatory mechanisms that influence this pathway.This investigation represents the first comprehensive analysis of five distinct mechanisms through which natural compounds modulate key molecules within the Hh pathway and their impact on the aggressive behaviors of BC.Furthermore,by exploring the structure-activity relationships between these compounds and their molecular targets,we shed light on the specific structural features that enable natural compounds to interact with various components of the Hh pathway.These novel insights contribute to advancing the development and clinical application of natural compound-based therapeutics.Our thorough review not only lays the groundwork for exploring innovative BC treatments but also opens new avenues for leveraging natural compounds in cancer therapy.
基金supported by the Weiqiao-UCAS Special Projects on Low-Carbon Technology Development(No.GYY-DTFZ-2022-007)the Fundamental Research Funds for the Central Universities(No.E0E48927×2)the National Natural Science Foundation of China(No.21677145).
文摘Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.
基金supported by the National Natural Science Foundation of China(No.82273711).
文摘Existing evidence has demonstrated the association between exposure to volatile organic compounds(VOCs)and osteoporosis(OP)risk,but the underlying mechanistic framework remains unclear.This study aimed to explore potential pathways using adverse outcome pathway(AOP)analysis,and evidence this association in middle-to-old-aged American adults using the updated National Health and Nutrition Examination Survey data.Multivariable-adjusted general linear and weighted quantile sum models were employed to analyze associations of VOC metabolites(VOCMs),representing internal VOCs exposure levels,with OP-related phenotypes.An AOP framework based on network analysis was developed by extracting target genes and phenotypes.Among 3555 American adults aged≥40 years(539 OP participants),we found that increasing urinary 3-and 4-methylhippuric acid,N-acetyl-S-(n-propyl)-l-cysteine(BPMA),and N-acetyl-S-(3-hydroxypropyl)-l-cysteine were associated with elevated OP odds with odds ratios(ORs)(95%confidence intervals,95%CIs)being 1.254(1.016 to 1.548),1.182(1.014 to 1.377),and 1.244(1.029 to 1.505),respectively,per standard deviation.Urinary BPMA and N-acetyl-S-(2-cyanoethyl)-l-cysteine were inversely associated with lumbar spine bone mineral density(BMD),while urinary N-acetyl-S-(2-hydroxypropyl)-l-cysteine was positively associated with hip BMD.Additionally,OP odds increased by 46.0%(95%CI:3.9%to 105.1%)per quartile increment in the VOC mixture.AOP analysis identified 53 target genes and 9 target phenotypes,and 5 of 9 target phenotypes were oxidative stress(OS)-related.Literature and the“AOP 482”framework implied the core role of OS in the VOC exposure and prevalent OP association,with the interleukin-6 as themolecular initiating event.Our findings provided a theoretical basis for further investigation.
基金the financial support from the National Natural Science Foundation of China(No.22178181)the Fundamental Research Funds for the Central Universities(Nankai University(No.63253204))。
文摘Achieving sustainable energy and chemical production has become an important issue for human society.Photocatalysis has attracted much attention due to its ability to harness solar energy to drive chemical reactions.Metal sulfide-based photocatalysts(e.g.,Cd S,Zn In2S4)have shown substantial potential in biomass-based hydroxyl compound valorization.In this review,we summarize the recent progress in metal sulfide-based photocatalysts for the photo upgrading of biomass-derived hydroxyl compounds coupled with reduction reactions(e.g.,CO_(2)reduction,H_(2)O_(2)generation,and H_(2)evolution).The mechanism of biomass redox reactions is discussed,highlighting the potential of realizing the valorization of biomass-derived compounds coupled with the reduction reactions,which is beneficial for researchers to actively explore biomass biorefinery pathways in order to modulate the selectivity of the valueadded products.Various modification strategies are presented,including elemental doping,defect engineering,heterojunction construction,and cocatalyst loading.These strategies modulate the energy band structure,surface electron density,and built-in electric field strength of metal sulfide-based photocatalysts,thereby enhancing their photocatalytic performance.The challenges and prospects of metal sulfidebased photocatalysts in biomass valorization are analyzed.This approach contributes to the development of photocatalysts that can accelerate biomass photo-upgrading coupling reactions.This review aims to provide deeper insights into the photocatalytic biorefinery pathways and contribute to the development of functionalized photocatalysts that can accelerate biomass photo upgrading,highlighting the synergistic effects of multiple coupling reactions.
文摘The associations of volatile organic compounds(VOCs)exposure with short sleep duration(SSD)have rarely been studied.We aimed to evaluate the correlation between VOC exposure and SSD risk,while also exploring the potential mediating influence of depressive symptoms.Blood concentrations of seven VOCs,namely benzene,toluene,ethylbenzene,m-/p-xylene,o-xylene,styrene(collectively known as BTEXS),and 1,4-dichlorobenzene,were analyzed in 2905 U.S.adults.Weighted logistic regression,quantile-based g-computation(QGC),and weighted quantile sum(WQS)regression were employed to investigate associations between selected VOCs and SSD risk.Mediation analyses were conducted to explore the potential mediating effects of depressive symptoms on these relationships.Increased blood levels of BTEXS were positively correlated with SSD risk,with odds ratios(OR)ranging from 1.130 to 1.212(all P<0.05).A nonlinear association between toluene concentration and SSD risk was observed(P for nonlinearity=0.028).Both QGC and WQS analyses indicated a positive association between co-exposure to VOCs and SSD,with styrene showing the highest positive weights(QGC:OR=1.313,95%confidence interval(CI):1.038–1.660;WQS:OR=1.386,95%CI:1.111–1.731).Furthermore,BTEXS exposure was positively linked to depressive symptoms,which in turn were significantly associated with SSD risk.Mediation analyses revealed that depressive symptoms partially mediated the relationships between individual and mixed VOCs and SSD risk,with mediation proportions ranging from 15.87%to 20.54%(all P<0.05).These findings indicated that exposure to VOCs increased SSD risk,with depressive symptoms playing a partial mediating role.
基金financially supported by the National Natural Science Foundation of China-Outstanding Young Scholars(52325407)National Natural Science Foundation of China(52474401)+1 种基金Project funded by China Postdoctoral Science Foundation(No.2022M712919)Guangdong Basic and Applied Basic Research Foundation(2023A1515140124,2025A1515012873,2022A1515140028,2022A1515010761).
文摘The microstructural evolution at the liquid Al/solid Ni interface during remelting and resolidification was dynamically observed by using synchrotron radiography.The formation and growth behavior of Al_(3)Ni_(2) and Al_(3)Ni brittle intermetallic compounds(IMCs)under different conditions was investigated,and the formation mechanisms of dendritic Al_(3)Ni crystals with different morphologies were elucidated.The increasing remelting cycles accelerated the formation of Al_(3)Ni_(2) layer and the growth of Al_(3)Ni IMCs.The increased-step heating temperatures and time promoted the morphological transition from faceted to non-faceted dendritic Al_(3)Ni,which was attributed to the enhanced undercooling during solidification and incompletely remelted Al_(3)Ni IMCs during remelting.The growth of regular Al_(3)Ni dendrites was dominated by coalescence of secondary dendrite arms,while the growth of irregular dendrites Al_(3)Ni was controlled by dendrite merging,radial melting and axial melting of secondary arms.The axially free dendritic Al_(3)Ni was attributed to the small distance between adjacent main trunks,and the dense secondary arms promoted the formation of local solute depletion regions.
基金financially supported by the National Natural Science Foundation of China(No.22176041,T2421005)National Key R&D Program of China(No.2022YFC3901800)+1 种基金the Fundamental Research Funds for the Central Universities(No.2243200011)Guangzhou Science and Technology Planning Project(No.2023A04J0918).
文摘Wide bandgap semiconductors are typically activated under ultraviolet(UV)light irradiation for volatile organic compounds(VOCs)degradation.However,our previous study discovered that certain VOCs can interact with some wide bandgap semiconductors,formatting an intermediate bandgap between the VOCs and the conduction band of wide bandgap semiconductor,thus inducing visible light activation of the system,and photo-generated electrons are excited by visible light and transferred from the VOCs to the conduction band of semiconductor.In this work,BaTiO_(3),traditionally is not active under visible light irradiation,however showed degradation rates of 100%and 20%for styrene and toluene under visible light,respectively.Density functional theory(DFT)calculations indicate that the adsorption of styrene or toluene on the BaTiO_(3)surface reduces its bandgap from 2.93 eV to 1.36 eV and 2.26 eV,respectively.The intermediate bandgap in this system is primarily formed by the valence band of BaTiO_(3)and the VOCs,and indicating that photo-generated electrons directly transfer from BaTiO_(3)to the VOCs under visible light,inducing degradation reactions of VOCs,i.e.,this work discovered a new transfer pathway of photo-electrons direct from the valence band of BaTiO_(3)to VOCs,while photo-electrons are from VOCs to the conductive band of wide-bandgap semiconductors in our previous work.
基金the Yunnan Fundamental Research Projects(Grant Nos.202501AT070298,202401AU070163,and 202401AT070368)the National Natural Science Foundation of China(Grant No.52162030)+5 种基金the Yunnan Major Scientific and Technological Projects(Grant No.202202AG050003)the Yunnan Engineering Research Center Innovation Ability Construction and Enhancement Projects(Grant No.2023-XMDJ-00617107)the University Service Key Industry Project of Yunnan Province(Grant No.FWCY-ZD2024005)the Yunnan Thousand Talents Program for Young Talents(Grant No.KKS2202052001)the Scientific Research Foundation of Kunming University of Science and Technology(Grant No.20220122)the Analysis and Testing Foundation of Kunming University of Science and Technology(Grant No.2023T20220122).
文摘The presence of residual alkaline compounds in the ultrahigh-nickel layered oxide cathodes(LiNi_(x)Co_(y)Mn_(1−x−y)O_(2),x≥_(0.9))aggravates structural degradation,increases surface reactivity,and promotes slurry gelation,leading to the capacity decay of batteries with these cathodes and complicating their manufacturing.Traditional approaches for addressing this issue,including direct removal,coverage,and utilization,are complex and require surface regeneration.Herein,we propose neutralizing residual alkaline compounds with 3-thiopheneboronic acid(3-TBA)to improve the performance of LiNi_(0.9)5Co_(0.04)Mn_(0.01)O_(2)(NCM)cathode material,a facile strategy that does not require any post-treatment.The suggested reaction yields a uniform and thin organic-modified layer on the surface of the NCM cathode,improving its chemical stability toward the electrolyte,as demonstrated by multiple characterization methods.The modified NCM cathode exhibited impressive cyclic and rate performances,achieving a capacity retention of 83.34%after 200 cycles at 1.0 C and a specific capacity of 162.00 mAh·g^(−1) at 10.0 C.Most importantly,the proposed approach can efficiently suppress unfavorable phase transitions,severe electrolyte degradation,and CO_(2) gas evolution,improving the application potential of ultrahigh-nickel layered oxide cathode materials.
基金supported by the National Key R&D Program of China(No.2023YFC3705801)the National Natural Science Foundation of China(No.42177085).
文摘Substantial effects of photochemical reaction losses of volatile organic compounds(VOCs)on factor profiles can be investigated by comparing the differences between daytime and nighttime dispersion-normalized VOC data resolved profiles.Hourly speciated VOC data measured in Shijiazhuang,China from May to September 2021 were used to conduct study.The mean VOC concentration in the daytime and at nighttime were 32.8 and 36.0 ppbv,respectively.Alkanes and aromatics concentrations in the daytime(12.9 and 3.08 ppbv)were lower than nighttime(15.5 and 3.63 ppbv),whereas that of alkenes showed the opposite tendency.The concentration differences between daytime and nighttime for alkynes and halogenated hydrocarbonswere uniformly small.The reactivities of the dominant species in factor profiles for gasoline emissions,natural gas and diesel vehicles,and liquefied petroleum gas were relatively low and their profiles were less affected by photochemical losses.Photochemical losses produced a substantial impact on the profiles of solvent use,petrochemical industry emissions,combustion sources,and biogenic emissions where the dominant species in these factor profiles had high reactivities.Although the profile of biogenic emissions was substantially affected by photochemical loss of isoprene,the low emissions at nighttime also had an important impact on its profile.Chemical losses of highly active VOC species substantially reduced their concentrations in apportioned factor profiles.This study results were consistent with the analytical results obtained through initial concentration estimation,suggesting that the initial concentration estimation could be the most effective currently availablemethod for the source analyses of active VOCs although with uncertainty.
文摘The disconnection between teaching,learning,and evaluation is particularly pronounced in traditional high school chemistry teaching.To align with the demands of the new curriculum standards for talent development,it is essential to implement reforms and innovations in teaching methods.This paper initially elucidates the integrated concept of teaching,learning,and evaluation,as well as its practical significance in the classroom.Subsequently,it explores the effective teaching design centered on the theme of iron and its compounds,actively investigating the implementation approach of the integration principle of teaching,learning,and evaluation in classroom.Furthermore,the paper emphasizes the pivotal role of the evaluation part in fostering the professional development of teachers and enhancing the core competencies of students,ultimately aiming to achieve high efficiency and quality in chemistry classroom teaching.
基金National Natural Science Foundation of China(NSFC,No.21971093)the Fundamental Research Funds for the Central Universities(No.lzujbky-2021-sp53)+2 种基金the International Joint Research centre for Green Catalysis and Synthesis(No.2016B01017)The Science and Technology Major Program of Gansu Province of China(No.22ZD6FA006)the 111 project for support of our research.We also thank the Canada Research Chair(Tier I)foundation,the E.B。
文摘Carbonyl compounds are abundant in nature and represent a substantial portion of biomass resources.Despite significant recent progress in homo-coupling of carbonyl compounds,achieving their deoxyfunctionalization homo-coupling remains a highly intricate challenge.Herein,we report an entirely novel reaction paradigm:the trifluoromethylative homo-coupling of carbonyl compounds via hydrazones,which enables the formation of three C(sp^(3))-C(sp^(3))bonds in a single step.This method provides a new pathway for synthesizing trifluoromethylative coupling product which has unique applications in both fields of medical and material sciences.Mechanistic investigations have unveiled that the formation of a trifluoromethyl-substituted benzyl radical plays a pivotal role as a key intermediate in this reaction.
