BACKGROUND The coronavirus disease 2019(COVID-19)pandemic disrupted healthcare in the United States.AIM To investigate COVID-19-related and non-COVID-19-related death and characteristics associated with excess death a...BACKGROUND The coronavirus disease 2019(COVID-19)pandemic disrupted healthcare in the United States.AIM To investigate COVID-19-related and non-COVID-19-related death and characteristics associated with excess death among inflammatory bowel disease(IBD)decedents.METHODS We performed a register-based study using data from the National Vital Statistics System,which reports death data from over 99%of the United States population,from January 1,2006 through December 31,2021.IBD-related deaths among adults 25 years and older were stratified by age,sex,race/ethnicity,place of death,and primary cause of death.Predicted and actual age-standardized mortality rates(ASMRs)per 100000 persons were compared.RESULTS 49782 IBD-related deaths occurred during the study period.Non-COVID-19-related deaths increased by 13.14%in 2020 and 18.12%in 2021[2020 ASMR:1.55 actual vs 1.37 predicted,95%confidence interval(CI):1.26-1.49;2021 ASMR:1.63 actual vs 1.38 predicted,95%CI:1.26-1.49].In 2020,non-COVID-19-related mortality increased by 17.65%in ulcerative colitis(UC)patients between the ages of 25 and 65 and 36.36%in non-Hispanic black(NHB)Crohn’s disease(CD)patients.During the pandemic,deaths at home or on arrival and at medical facilities as well as deaths due to neoplasms also increased.CONCLUSION IBD patients suffered excess non-COVID-19-related death during the pandemic.Excess death was associated with younger age among UC patients,and with NHB race among CD patients.Increased death at home or on arrival and due to neoplasms suggests that delayed presentation and difficulty accessing healthcare may have led to increased IBD mortality.展开更多
The development of high-performance electrocatalysts for hydrogen evolution reaction(HER)is of great significance for green,sustainable,and renewable energy conversion.Herein,we report the synthesis of amorphous Ru cl...The development of high-performance electrocatalysts for hydrogen evolution reaction(HER)is of great significance for green,sustainable,and renewable energy conversion.Herein,we report the synthesis of amorphous Ru clusters on Co-doped defect-rich hollow carbon nanocage(a-Ru@Co-DHC)as an efficient electrocatalyst for HER in the basic media.Due to the advantages such as high surface area,rich edge defect,atomic Co doping and amorphous Ru clusters,the as-made a-Ru@Co-DHC displays an efficient HER performance with a near-zero onset overpotential,a low Tafel slope(62 mV dec^(−1)),a low overpotential of 40 mV at 10 mA cm^(−2) and high stability,outperforming the commercial Ru nanocrystal/C,commercial Pt/C,and other reported Ru-based catalysts.This work provides a new insight into designing new metal doped carbon nanocages catalysts supported by amorphous nanoclusters for achieving the enhanced electrocatalysis.展开更多
Whether the Altyn Tagh fault (ATF) had been extended beyond its current northeastern tip and linked with strike-slip faults in East Asia is a key to understanding the timing and mechanisms of crustal deformation in th...Whether the Altyn Tagh fault (ATF) had been extended beyond its current northeastern tip and linked with strike-slip faults in East Asia is a key to understanding the timing and mechanisms of crustal deformation in the northern Tibetan Plateau. We present Late Cretaceous dextral movement affected by Okhotomorsk Block-East Asia collision and a larger sinistral offset since Late Eocene along the ATF based on the provenance analysis of western Jiuxi Basin. Moreover, currently available estimates of offset based on displaced Paleozoic and Jurassic rocks could not represent the maximum offset due to late Cretaceous dextral offset.展开更多
In the past 37 years,human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)has undergone various major transmission routes in China,with the world most complex co-circulating HIV-1 subtypes,even the...In the past 37 years,human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)has undergone various major transmission routes in China,with the world most complex co-circulating HIV-1 subtypes,even the prevalence is still low.In response to the first epidemic outbreak of HIV in injecting drug users and the second one by illegal commercial blood collection,China issued the Anti-Drug Law and launched the Blood Donation Act and nationwide nucleic acid testing,which has avoided 98,232 to 211,200 estimated infections and almost ended the blood product-related infection.China has been providing free antiretroviral therapy(ART)since 2003,which covered>80%of the identified patients and achieved a viral suppression rate of 91%.To bend the curve of increasing the disease burden of HIV and finally end the epidemic,China should consider constraining HIV spread through sexual transmission,narrowing the gaps in identifying HIV cases,and the long-term effectiveness and safety of ART in the future.展开更多
Despite various 2H-MoS/carbon hybrid nanostructures have been constructed and committed to improve the performance for sodium-ion batteries(SIBs),they still show the limited cycle stability due to the relatively large...Despite various 2H-MoS/carbon hybrid nanostructures have been constructed and committed to improve the performance for sodium-ion batteries(SIBs),they still show the limited cycle stability due to the relatively large volumetric expansion during the charge-discharge process Herein,we report the construction of cobalt-doped few-layered 1T-MoS2 nanosheets embedded in N,S-doped carbon(CMS/NSC)nanobowls derived from metal-organic framework(MOF)precursor via a simple in situ sulfurization process.This unique hierarchical structure enables the uniformly dispersed Co-doped 1T-MoS2 nanosheets intimately couple with the highly conductive carbon nanobowls,thus efficiently preventing the aggregation.In particular,the Co-doping plays a crucial role in maintaining the integrity of structure for MoS2 during cycling tests,confirmed by first-principles calculations.Compared with pristine MoS2,the volume deformation of Co-doped MoS2 can be shrunk by a prominent value of 52%during cycling.Furthermore,the few-layered MoS2 nanosheets with 1T metalic phase endow higher conductivity,and thus can surpass its counterpart 2H semiconducting phase in battery performance.By virtue of the synergistic effect of stable structure,appropriate doping and high conductivity,the resulting CMS/NSC hybrid shows superior rate capability and cycle stability.The capacity of CMS/NSC can still be 235.9 mAh·g^-1 even at 25 A·g^-1,which is 51.3%of the capacity at 0.2 A·g^-1.Moreover,the capacity can still remain 218.6 mAh·g^-1 even over 8,240 cycles at 5 Ag·g^-1 with a low decay of 0.0044%per cycle,one of the best performances among the reportec MoS2-based anode materials for SIBs.展开更多
Highly-branched dendritic Pt-based nanocrystals possess great potential in catalyzing the oxygen reduction reaction(ORR),but encounter performance ceiling due to their poor thermal and electrochemical stability.Here,w...Highly-branched dendritic Pt-based nanocrystals possess great potential in catalyzing the oxygen reduction reaction(ORR),but encounter performance ceiling due to their poor thermal and electrochemical stability.Here,we present a novel Pt Fe nanodendrites(NDs)branched with two-dimensional(2 D)twinned nanoplates rather than conventional 1 D nanowires,which breaks the ORR performance ceiling of dendritic catalysts by inducing the unique Pt-skin configuration via rationally thermal treatment.By further hybridizing the Pt-skin Pt Fe NDs/C with amino-functionalized ionic liquids(ILs),we achieve an unprecedented mass activity of 3.15 A/mgPtat 0.9 V versus reversible hydrogen electrode(RHE)in the Pt Fe-based ORR electrocatalytic system.They also show excellent electrocatalytic durability for ORR with negligible activity decay and no apparent structural change after 20,000 cycles,in sharp contrast to the nanowires branched Pt Fe NDs counterpart.The remarkable catalytic performance is attributed to a combination of several structural features,including 2 D morphology,twin boundary,partially ordered phase and strong coordination with amino group.This work highlights the significance of stabilizing electrocatalytic structures via morphology tuning,which thus enables further surface and interface modification for performance breakthrough in ORR electrocatalysis.展开更多
Building highly active and stable noble metal single atom(MSA)catalyst onto photocatalyst materials for nitrogen reduction reaction(NRR)and CO2 reduction reaction(CRR)is a key to future renewable energy conversion and...Building highly active and stable noble metal single atom(MSA)catalyst onto photocatalyst materials for nitrogen reduction reaction(NRR)and CO2 reduction reaction(CRR)is a key to future renewable energy conversion and storage technologies.Here we present a design strategy to optimize the stability and electronic property of noble metal single atoms(MSAs,M=Rh,Pd,Ag,Ir,Pt,Au)catalyst supported on g-C3N4 and 2H-MoS2 photocatalysts towards NRR and CRR.Our results indicate that the MSAs tend to be trapped at the anion-vacancy sites of photocatalyst rather than the pristine photocatalyst surface.This anion vacancy can promise the MSAs with an optimized electron-captured ability in the photoexcitation process,thus decreasing the energy barriers of NRR and CRR on MSAs.Especially,it is revealed that the N-vacancy-stabilized Ir SA on g-C3N4 and the S-vacancy-stabilized RhSA on 2H-MoS2 own the lowest energy barrier in NRR.However,for CRR,the HCOOH is the main product on MSAs supported by gC3N4 and 2H-MoS2.The N-vacancy-stabilized PdSA on g-C3N4 and the S-vacancy-stabilized AuSA on 2H-MoS2 show the lowest energy barrier for HCOOH production in CRR.This finding offers an approach to design specific active MSA centres on photocatalysts by the anion vacancy engineering.展开更多
Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method ...Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method to fabricate a series of core@shell Ni@RuM(M=Ni or Co)nanocrystals(NCs)with Ni as the core and tunable RuM(M=Ni or Co)as the alloy shell for efficient water-splitting catalysis.Among these core@shell NCs,the obtained Ni@Ru Ni NCs exhibit the highest intrinsic activity for hydrogen evolution reaction(HER)and possess an outstanding mass activity of 1590 m A mgRu^-1 at 0.07 V vs.reversible hydrogen electrode(RHE),which is 1.7 times higher than that of commercial Pt/C(950 m A mgPt^-1).As for oxygen evolution reaction(OER),the prepared Ni@Ru0.4 Co0.6 NCs with optimized shell composition achieve more enhanced mass activity of 270 m A mgRu^-1 at1.56 V vs.RHE,approaching three times higher than that of commercial RuO2(89 m A mgRu^-1).The superb mass activity of these Ni@Ru M(M=Ni or Co)NCs can be attributed to their core@shell structure and modulated electronic structure through alloying with Ni or Co metal in the shell.展开更多
To understand the influence patterns and interactions of three important environmental factors,i.e.soil water content,oxygen concentration,and ammonium addition,on methane oxidation,the soils from landfill cover layer...To understand the influence patterns and interactions of three important environmental factors,i.e.soil water content,oxygen concentration,and ammonium addition,on methane oxidation,the soils from landfill cover layers were incubated under full factorial parameter settings.In addition to the methane oxidation rate,the quantities and community structures of methanotrophs were analyzed to determine the methane oxidation capacity of the soils.Canonical correspondence analysis was utilized to distinguish the important impact factors.Water content was found to be the most important factor influencing the methane oxidation rate and Type II methanotrophs,and the optimum value was 15%(w/w),which induced methane oxidation rates 10-and 6-times greater than those observed at 5%(w/w)and 20%(w/w),respectively.Ambient oxygen conditions were more suitable for methane oxidation than 3%oxygen.The addition of 100 mg-N·kg^(-1) drysoil of ammonium induced different effects on methane oxidation capacity when conducted at low or high water content.With regard to the methanotrophs,Type II was sensitive to the changes of water content,while Type I was influenced by oxygen content.Furthermore,the methanotrophic acidophile,Verrucomicrobia,was detected in soils with a pH of 4.9,which extended their known living environments.展开更多
In this paper, Ni-Co coatings were electrodeposited onto carbon steel substrates with the aid of ultrasonic agitation. The coatings were analyzed by energy dispersive X-ray analysis (EDX), X-ray diffraction analysis...In this paper, Ni-Co coatings were electrodeposited onto carbon steel substrates with the aid of ultrasonic agitation. The coatings were analyzed by energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The effects of the ultrasonic frequency on the roughness, hardness and corrosion resistance of the Ni-Co coatings were also investigated. The results indicated that the increase of the ultrasonic frequency from 20 to 120 kHz reduced the Ni content and the grain size of Ni-Co coatings. Moreover, the phase structure of the electrodeposited coatings was influenced by the ultrasonic frequency. Under 55 kHz ultrasonic agitation, the Ni-Co coating was single fcc phase and showed the finest roughness and the strongest corrosion resistance in 5 wt.% NaCl solution at the ambient temperature. Under ultrasonic agitation with frequency of 90 kHz, the coating was a mixture of fcc and hcp structure and showed the maximal hardness of about 420 HV. Therefore, ultrasonic agitation helped decrease the roughness, and enhance hardness and corrosion resistance of Ni-Co coatings.展开更多
Immunocompromised status and interrupted routine care may render patients with cirrhosis vulnerable to the coronavi-rus disease 2019(COVID-19)pandemic.A nationwide data-set that includes more than 99%of the decedents ...Immunocompromised status and interrupted routine care may render patients with cirrhosis vulnerable to the coronavi-rus disease 2019(COVID-19)pandemic.A nationwide data-set that includes more than 99%of the decedents in the U.S.between April 2012 and September 2021 was used.Projected age-standardized mortality during the pandemic were esti-mated according to prepandemic mortality rates,stratified by season.Excess deaths were determined by estimating the difference between observed and projected mortality rates.A temporal trend analysis of observed mortality rates was also performed in 0.83 million decedents with cirrhosis between April 2012 and September 2021 was included.Following an increasing trend of cirrhosis-related mortality before the pandemic,with a semiannual percentage change(SAPC)of 0.54%[95%confidence interval(CI):(0.0-1.0%),p=0.036],a precipitous increase with seasonal variation occurred dur-ing the pandemic(SAPC 5.35,95%CI:1.9-8.9,p=0.005).Significantly increased mortality rates were observed in those with alcohol-associated liver disease(ALD),with a SAPC of 8.44(95%CI:4.3-12.8,p=0.001)during the pandemic.All-cause mortality of nonalcoholic fatty liver disease rose stead-ily across the entire study period with a SAPC of 6.79(95%CI:6.3-7.3,p<0.001).The decreasing trend of HCV-related mortality was reversed during the pandemic,while there was no significant change in HBV-related deaths.While there was significant increase in COVID-19-related deaths,more than 55%of the excess deaths were the indirect impact of the pandemic.We observed an alarming increase in cirrhosis-related deaths during the pandemic especially for ALD,with evidence in both direct and indirect impact.Our findings have implications on formulating policies for patients with cirrhosis.展开更多
Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries(SIBs)due to their high theoretical capacity and low cost.However,they deliver unsatisfac...Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries(SIBs)due to their high theoretical capacity and low cost.However,they deliver unsatisfactory performance in practice,owing to their intrinsically low conductivity,sluggish kinetics and volume expansion during the charge-discharge process.Herein,we demonstrate the synthesis of SnSe2 nanocrystals coupled with hierarchical porous carbon(SnSe2 NCs/C)microspheres for boosting SIBs in terms of capacity,rate ability and durability.The unique structure of SnSe2 NCs/C possesses several advantages,including inhibiting the agglomeration of SnSe2 nanoparticles,relieving the volume expansion,accelerating the diffusion kinetics of electrons/ions,enhancing the contact area between the electrode and electrolyte and improving the structural stability of the composite.As a result,the as-obtained SnSe2 NCs/C microspheres show a high reversible capacity(565 mA h g^-1 after 100 cycles at 100 mA g^-1),excellent rate capability,and long cycling life stability(363 mA h g^-1 at1 A g^-1 after 1000 cycles),which represent the best performances among the reported SIBs based on SnSe2-based anode materials.展开更多
Fluorescent dyes are heavily sought for their potentials applications in bioimaging, sensing, theranostic,and optoelectronic materials. Among them, BODIPY dyes are privileged fluorophores that are now widely used in h...Fluorescent dyes are heavily sought for their potentials applications in bioimaging, sensing, theranostic,and optoelectronic materials. Among them, BODIPY dyes are privileged fluorophores that are now widely used in highly diverse research fields. The increasing success of BODIPY dyes is closely associated with their excellent and tunable photophysical properties due to their rich functionalization chemistry.Recently, growing research efforts have been devoted to the direct functionalization of the BODIPY core,because it allows the facile installation of desired functional groups in a single atom economical step. The challenges of this direct C-H derivation come from the difficulties in finding suitable functionalization agents and proper control of the regioselectivity of the functionalization. The aim of this work is to provide an overview of BODIPY dyes and a summarization of the different synthetic methodologies reported for direct C–H functionalization of the BODIPY framework.展开更多
Background:Neuroblastoma is an embryonic neoplasm originating from the neural crest with cellular heterogeneity as one of its oncobiological characteristics.This study was undertaken to determine whether human neurobl...Background:Neuroblastoma is an embryonic neoplasm originating from the neural crest with cellular heterogeneity as one of its oncobiological characteristics.This study was undertaken to determine whether human neuroblastoma contains stem ell-like cells.Methods:Twenty patients with neuroblastoma who have been treated in our hospital since January 2005 were divided into pre-operative chemotherapy(10 patients)and non-chemotherapy(10)groups.Tumor specimens of the patients were taken and paraffin sections were made.The expressions of stem cell markers CD133,ABCG2,CD117 and nestin were immunohistochemically detected in the specimens.Neuroblastoma cells were stained with Hoechst 33342 and PI.The side population(SP)cells were analyzed by the fluorescence activated cell sorter.The disparity drug resistance to cisplatin(DDP)of SP and non-SP cells was measured with MTT colorimetric assay.The oncogenicity of SP and non SP cells was identified in nude mice.Results:There was no significant difference in the expression intensity of CD117 and nestin between the two groups of specimens(P>0.05).There was a significant difference between the two groups in terms of the expression intensity of CD133 and ABCG2(P<0.05).The SP cells accounted for 0.2%-1.3%of the total human neuroblastoma cells and were decreased to 0.1%-0.5%after verapamil treatment.The SP and non-SP cells showed disparity in cell growth experiment and drug resistance to DDP.Oncogenicity experiment revealed that nude mice could erupt tumor by an injection of 1×10^(6)SH-SY5Y and WIV SP cells.However,the nude mice could not form tumor by an injection of 1×10^(6)non-SP cells.Conclusion:Neuroblastoma might contain cancer stem cell-like cells.展开更多
The low-cost and high-capacity metal oxides/oxyhydroxides possess great merits as anodes for lithium-ion batteries(LIBs)with high energy density.However,their commercialization is greatly hindered by insufficient rate...The low-cost and high-capacity metal oxides/oxyhydroxides possess great merits as anodes for lithium-ion batteries(LIBs)with high energy density.However,their commercialization is greatly hindered by insufficient rate capability and cyclability.Rational regulations of metal oxides/oxyhydroxides with hollow geometry and disordered atomic frameworks represent efficient ways to improve their electrochemical properties.Herein,we propose a fast alkalietching method to realize the in-situ fabrication of iron oxyhydroxide with one-dimensional(1D)hierarchical hollow nanostructure and amorphous atomic structure from the iron vanadate nanowires.Benefiting from the improved electron/ion kinetics and efficient buffer ability for the volumetric change during the electro-cycles both in nanoscale and atomic level,the graphene-modified amorphous hierarchical FeOOH nanotubes(FeOOH-NTs)display high rate capability(~650 mA h g^−1 at 2000 mA g^−1)and superior long-term cycling stability(463 mA h g^−1 after 1800 cycles),which represents the best cycling performance among the reported FeOOH-based materials.More importantly,the selective dissolutionregrowth mechanism is demonstrated based on the time tracking of the whole transition process,in which the dissolution of FeVO4 and the in-situ selective re-nucleation of FeOOH during the formation of FeOOH-NTs play the key roles.The present strategy is also a general method to prepare various metal(such as Fe,Mn,Co,and Cu)oxides/oxyhydroxides with 1D hierarchical nanostructures.展开更多
文摘BACKGROUND The coronavirus disease 2019(COVID-19)pandemic disrupted healthcare in the United States.AIM To investigate COVID-19-related and non-COVID-19-related death and characteristics associated with excess death among inflammatory bowel disease(IBD)decedents.METHODS We performed a register-based study using data from the National Vital Statistics System,which reports death data from over 99%of the United States population,from January 1,2006 through December 31,2021.IBD-related deaths among adults 25 years and older were stratified by age,sex,race/ethnicity,place of death,and primary cause of death.Predicted and actual age-standardized mortality rates(ASMRs)per 100000 persons were compared.RESULTS 49782 IBD-related deaths occurred during the study period.Non-COVID-19-related deaths increased by 13.14%in 2020 and 18.12%in 2021[2020 ASMR:1.55 actual vs 1.37 predicted,95%confidence interval(CI):1.26-1.49;2021 ASMR:1.63 actual vs 1.38 predicted,95%CI:1.26-1.49].In 2020,non-COVID-19-related mortality increased by 17.65%in ulcerative colitis(UC)patients between the ages of 25 and 65 and 36.36%in non-Hispanic black(NHB)Crohn’s disease(CD)patients.During the pandemic,deaths at home or on arrival and at medical facilities as well as deaths due to neoplasms also increased.CONCLUSION IBD patients suffered excess non-COVID-19-related death during the pandemic.Excess death was associated with younger age among UC patients,and with NHB race among CD patients.Increased death at home or on arrival and due to neoplasms suggests that delayed presentation and difficulty accessing healthcare may have led to increased IBD mortality.
文摘The development of high-performance electrocatalysts for hydrogen evolution reaction(HER)is of great significance for green,sustainable,and renewable energy conversion.Herein,we report the synthesis of amorphous Ru clusters on Co-doped defect-rich hollow carbon nanocage(a-Ru@Co-DHC)as an efficient electrocatalyst for HER in the basic media.Due to the advantages such as high surface area,rich edge defect,atomic Co doping and amorphous Ru clusters,the as-made a-Ru@Co-DHC displays an efficient HER performance with a near-zero onset overpotential,a low Tafel slope(62 mV dec^(−1)),a low overpotential of 40 mV at 10 mA cm^(−2) and high stability,outperforming the commercial Ru nanocrystal/C,commercial Pt/C,and other reported Ru-based catalysts.This work provides a new insight into designing new metal doped carbon nanocages catalysts supported by amorphous nanoclusters for achieving the enhanced electrocatalysis.
文摘Whether the Altyn Tagh fault (ATF) had been extended beyond its current northeastern tip and linked with strike-slip faults in East Asia is a key to understanding the timing and mechanisms of crustal deformation in the northern Tibetan Plateau. We present Late Cretaceous dextral movement affected by Okhotomorsk Block-East Asia collision and a larger sinistral offset since Late Eocene along the ATF based on the provenance analysis of western Jiuxi Basin. Moreover, currently available estimates of offset based on displaced Paleozoic and Jurassic rocks could not represent the maximum offset due to late Cretaceous dextral offset.
基金the Mega-Projects of national science research(13rd Five-Year Plan[No.2017ZX10201101])the Innovation Team Develop-ment Program of the Ministry of Education 2016(No.IRT_16R70).
文摘In the past 37 years,human immunodeficiency virus/acquired immunodeficiency syndrome(HIV/AIDS)has undergone various major transmission routes in China,with the world most complex co-circulating HIV-1 subtypes,even the prevalence is still low.In response to the first epidemic outbreak of HIV in injecting drug users and the second one by illegal commercial blood collection,China issued the Anti-Drug Law and launched the Blood Donation Act and nationwide nucleic acid testing,which has avoided 98,232 to 211,200 estimated infections and almost ended the blood product-related infection.China has been providing free antiretroviral therapy(ART)since 2003,which covered>80%of the identified patients and achieved a viral suppression rate of 91%.To bend the curve of increasing the disease burden of HIV and finally end the epidemic,China should consider constraining HIV spread through sexual transmission,narrowing the gaps in identifying HIV cases,and the long-term effectiveness and safety of ART in the future.
基金This work was financially supported by the National Key R&D Program of China(No.2016YFB0100200)Young Thousand Talents Program,the Open Project Foundation of State Key Laboratory of Chemical Resource Engineering,the China Postdoctoral Science Foundation(No.2017M610018)the National Natural Science Foundation of China(No.51671003),Start-up Funding from Peking University.
文摘Despite various 2H-MoS/carbon hybrid nanostructures have been constructed and committed to improve the performance for sodium-ion batteries(SIBs),they still show the limited cycle stability due to the relatively large volumetric expansion during the charge-discharge process Herein,we report the construction of cobalt-doped few-layered 1T-MoS2 nanosheets embedded in N,S-doped carbon(CMS/NSC)nanobowls derived from metal-organic framework(MOF)precursor via a simple in situ sulfurization process.This unique hierarchical structure enables the uniformly dispersed Co-doped 1T-MoS2 nanosheets intimately couple with the highly conductive carbon nanobowls,thus efficiently preventing the aggregation.In particular,the Co-doping plays a crucial role in maintaining the integrity of structure for MoS2 during cycling tests,confirmed by first-principles calculations.Compared with pristine MoS2,the volume deformation of Co-doped MoS2 can be shrunk by a prominent value of 52%during cycling.Furthermore,the few-layered MoS2 nanosheets with 1T metalic phase endow higher conductivity,and thus can surpass its counterpart 2H semiconducting phase in battery performance.By virtue of the synergistic effect of stable structure,appropriate doping and high conductivity,the resulting CMS/NSC hybrid shows superior rate capability and cycle stability.The capacity of CMS/NSC can still be 235.9 mAh·g^-1 even at 25 A·g^-1,which is 51.3%of the capacity at 0.2 A·g^-1.Moreover,the capacity can still remain 218.6 mAh·g^-1 even over 8,240 cycles at 5 Ag·g^-1 with a low decay of 0.0044%per cycle,one of the best performances among the reportec MoS2-based anode materials for SIBs.
基金supported by the National Key Research and Development Program of China(2016YFB0100201)the National Natural Science Foundation of China(51671003)+3 种基金Beijing Natural Science Foundation(JQ18005)BIC-ESAT Projectthe China Postdoctoral Science Foundation(2017M610022)Young Thousand Talented Program.
文摘Highly-branched dendritic Pt-based nanocrystals possess great potential in catalyzing the oxygen reduction reaction(ORR),but encounter performance ceiling due to their poor thermal and electrochemical stability.Here,we present a novel Pt Fe nanodendrites(NDs)branched with two-dimensional(2 D)twinned nanoplates rather than conventional 1 D nanowires,which breaks the ORR performance ceiling of dendritic catalysts by inducing the unique Pt-skin configuration via rationally thermal treatment.By further hybridizing the Pt-skin Pt Fe NDs/C with amino-functionalized ionic liquids(ILs),we achieve an unprecedented mass activity of 3.15 A/mgPtat 0.9 V versus reversible hydrogen electrode(RHE)in the Pt Fe-based ORR electrocatalytic system.They also show excellent electrocatalytic durability for ORR with negligible activity decay and no apparent structural change after 20,000 cycles,in sharp contrast to the nanowires branched Pt Fe NDs counterpart.The remarkable catalytic performance is attributed to a combination of several structural features,including 2 D morphology,twin boundary,partially ordered phase and strong coordination with amino group.This work highlights the significance of stabilizing electrocatalytic structures via morphology tuning,which thus enables further surface and interface modification for performance breakthrough in ORR electrocatalysis.
基金financially supported by the Tencent Foundation through the XPLORER PRIZE,Chinathe National Natural Science Foundation of China(51671003)+3 种基金the National Basic Research Program of China(2016YFB0100201)start-up support from Peking Universitythe Young Thousand Talented Programthe computation support from Jincai Zhao's group of Institute of Chemistry,Chinese Academy of Sciences。
文摘Building highly active and stable noble metal single atom(MSA)catalyst onto photocatalyst materials for nitrogen reduction reaction(NRR)and CO2 reduction reaction(CRR)is a key to future renewable energy conversion and storage technologies.Here we present a design strategy to optimize the stability and electronic property of noble metal single atoms(MSAs,M=Rh,Pd,Ag,Ir,Pt,Au)catalyst supported on g-C3N4 and 2H-MoS2 photocatalysts towards NRR and CRR.Our results indicate that the MSAs tend to be trapped at the anion-vacancy sites of photocatalyst rather than the pristine photocatalyst surface.This anion vacancy can promise the MSAs with an optimized electron-captured ability in the photoexcitation process,thus decreasing the energy barriers of NRR and CRR on MSAs.Especially,it is revealed that the N-vacancy-stabilized Ir SA on g-C3N4 and the S-vacancy-stabilized RhSA on 2H-MoS2 own the lowest energy barrier in NRR.However,for CRR,the HCOOH is the main product on MSAs supported by gC3N4 and 2H-MoS2.The N-vacancy-stabilized PdSA on g-C3N4 and the S-vacancy-stabilized AuSA on 2H-MoS2 show the lowest energy barrier for HCOOH production in CRR.This finding offers an approach to design specific active MSA centres on photocatalysts by the anion vacancy engineering.
基金funding from the National Natural Science Foundation of China (21427811, 21721003 and 51671003)the Ministry of Science and Technology, China (2016YFA0203200)+1 种基金the Youth Innovation Promotion Association CAS (2016208)Jilin Province Science Technology Development Plan Project (20170101194JC)
文摘Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method to fabricate a series of core@shell Ni@RuM(M=Ni or Co)nanocrystals(NCs)with Ni as the core and tunable RuM(M=Ni or Co)as the alloy shell for efficient water-splitting catalysis.Among these core@shell NCs,the obtained Ni@Ru Ni NCs exhibit the highest intrinsic activity for hydrogen evolution reaction(HER)and possess an outstanding mass activity of 1590 m A mgRu^-1 at 0.07 V vs.reversible hydrogen electrode(RHE),which is 1.7 times higher than that of commercial Pt/C(950 m A mgPt^-1).As for oxygen evolution reaction(OER),the prepared Ni@Ru0.4 Co0.6 NCs with optimized shell composition achieve more enhanced mass activity of 270 m A mgRu^-1 at1.56 V vs.RHE,approaching three times higher than that of commercial RuO2(89 m A mgRu^-1).The superb mass activity of these Ni@Ru M(M=Ni or Co)NCs can be attributed to their core@shell structure and modulated electronic structure through alloying with Ni or Co metal in the shell.
基金This work was financially supported by the National Key Technology R&D Program of China(No.2006BAJ04A06)the National High-Tech Research and Development Program(863 Program)of China(No.2003AA644020).
文摘To understand the influence patterns and interactions of three important environmental factors,i.e.soil water content,oxygen concentration,and ammonium addition,on methane oxidation,the soils from landfill cover layers were incubated under full factorial parameter settings.In addition to the methane oxidation rate,the quantities and community structures of methanotrophs were analyzed to determine the methane oxidation capacity of the soils.Canonical correspondence analysis was utilized to distinguish the important impact factors.Water content was found to be the most important factor influencing the methane oxidation rate and Type II methanotrophs,and the optimum value was 15%(w/w),which induced methane oxidation rates 10-and 6-times greater than those observed at 5%(w/w)and 20%(w/w),respectively.Ambient oxygen conditions were more suitable for methane oxidation than 3%oxygen.The addition of 100 mg-N·kg^(-1) drysoil of ammonium induced different effects on methane oxidation capacity when conducted at low or high water content.With regard to the methanotrophs,Type II was sensitive to the changes of water content,while Type I was influenced by oxygen content.Furthermore,the methanotrophic acidophile,Verrucomicrobia,was detected in soils with a pH of 4.9,which extended their known living environments.
基金financially supported by the National Nature Science Fund of China(No.51204115)
文摘In this paper, Ni-Co coatings were electrodeposited onto carbon steel substrates with the aid of ultrasonic agitation. The coatings were analyzed by energy dispersive X-ray analysis (EDX), X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The effects of the ultrasonic frequency on the roughness, hardness and corrosion resistance of the Ni-Co coatings were also investigated. The results indicated that the increase of the ultrasonic frequency from 20 to 120 kHz reduced the Ni content and the grain size of Ni-Co coatings. Moreover, the phase structure of the electrodeposited coatings was influenced by the ultrasonic frequency. Under 55 kHz ultrasonic agitation, the Ni-Co coating was single fcc phase and showed the finest roughness and the strongest corrosion resistance in 5 wt.% NaCl solution at the ambient temperature. Under ultrasonic agitation with frequency of 90 kHz, the coating was a mixture of fcc and hcp structure and showed the maximal hardness of about 420 HV. Therefore, ultrasonic agitation helped decrease the roughness, and enhance hardness and corrosion resistance of Ni-Co coatings.
文摘Immunocompromised status and interrupted routine care may render patients with cirrhosis vulnerable to the coronavi-rus disease 2019(COVID-19)pandemic.A nationwide data-set that includes more than 99%of the decedents in the U.S.between April 2012 and September 2021 was used.Projected age-standardized mortality during the pandemic were esti-mated according to prepandemic mortality rates,stratified by season.Excess deaths were determined by estimating the difference between observed and projected mortality rates.A temporal trend analysis of observed mortality rates was also performed in 0.83 million decedents with cirrhosis between April 2012 and September 2021 was included.Following an increasing trend of cirrhosis-related mortality before the pandemic,with a semiannual percentage change(SAPC)of 0.54%[95%confidence interval(CI):(0.0-1.0%),p=0.036],a precipitous increase with seasonal variation occurred dur-ing the pandemic(SAPC 5.35,95%CI:1.9-8.9,p=0.005).Significantly increased mortality rates were observed in those with alcohol-associated liver disease(ALD),with a SAPC of 8.44(95%CI:4.3-12.8,p=0.001)during the pandemic.All-cause mortality of nonalcoholic fatty liver disease rose stead-ily across the entire study period with a SAPC of 6.79(95%CI:6.3-7.3,p<0.001).The decreasing trend of HCV-related mortality was reversed during the pandemic,while there was no significant change in HBV-related deaths.While there was significant increase in COVID-19-related deaths,more than 55%of the excess deaths were the indirect impact of the pandemic.We observed an alarming increase in cirrhosis-related deaths during the pandemic especially for ALD,with evidence in both direct and indirect impact.Our findings have implications on formulating policies for patients with cirrhosis.
基金supported by the National Key R&D Research Program of China (2016YFB0100201)Beijing Natural Science Foundation (JQ18005)+2 种基金the National Natural Science Foundation of China (51671003, 21802003)China Postdoctoral Science Foundation (2019TQ0001)the start-up supports from Peking University and Young Thousand Talented Program
文摘Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries(SIBs)due to their high theoretical capacity and low cost.However,they deliver unsatisfactory performance in practice,owing to their intrinsically low conductivity,sluggish kinetics and volume expansion during the charge-discharge process.Herein,we demonstrate the synthesis of SnSe2 nanocrystals coupled with hierarchical porous carbon(SnSe2 NCs/C)microspheres for boosting SIBs in terms of capacity,rate ability and durability.The unique structure of SnSe2 NCs/C possesses several advantages,including inhibiting the agglomeration of SnSe2 nanoparticles,relieving the volume expansion,accelerating the diffusion kinetics of electrons/ions,enhancing the contact area between the electrode and electrolyte and improving the structural stability of the composite.As a result,the as-obtained SnSe2 NCs/C microspheres show a high reversible capacity(565 mA h g^-1 after 100 cycles at 100 mA g^-1),excellent rate capability,and long cycling life stability(363 mA h g^-1 at1 A g^-1 after 1000 cycles),which represent the best performances among the reported SIBs based on SnSe2-based anode materials.
基金supported by the National Nature Science Foundation of China (Nos. 21672006, 21672007 and 21871006)
文摘Fluorescent dyes are heavily sought for their potentials applications in bioimaging, sensing, theranostic,and optoelectronic materials. Among them, BODIPY dyes are privileged fluorophores that are now widely used in highly diverse research fields. The increasing success of BODIPY dyes is closely associated with their excellent and tunable photophysical properties due to their rich functionalization chemistry.Recently, growing research efforts have been devoted to the direct functionalization of the BODIPY core,because it allows the facile installation of desired functional groups in a single atom economical step. The challenges of this direct C-H derivation come from the difficulties in finding suitable functionalization agents and proper control of the regioselectivity of the functionalization. The aim of this work is to provide an overview of BODIPY dyes and a summarization of the different synthetic methodologies reported for direct C–H functionalization of the BODIPY framework.
基金supported by a grant from the National Natural Science Foundation of China(81272803).
文摘Background:Neuroblastoma is an embryonic neoplasm originating from the neural crest with cellular heterogeneity as one of its oncobiological characteristics.This study was undertaken to determine whether human neuroblastoma contains stem ell-like cells.Methods:Twenty patients with neuroblastoma who have been treated in our hospital since January 2005 were divided into pre-operative chemotherapy(10 patients)and non-chemotherapy(10)groups.Tumor specimens of the patients were taken and paraffin sections were made.The expressions of stem cell markers CD133,ABCG2,CD117 and nestin were immunohistochemically detected in the specimens.Neuroblastoma cells were stained with Hoechst 33342 and PI.The side population(SP)cells were analyzed by the fluorescence activated cell sorter.The disparity drug resistance to cisplatin(DDP)of SP and non-SP cells was measured with MTT colorimetric assay.The oncogenicity of SP and non SP cells was identified in nude mice.Results:There was no significant difference in the expression intensity of CD117 and nestin between the two groups of specimens(P>0.05).There was a significant difference between the two groups in terms of the expression intensity of CD133 and ABCG2(P<0.05).The SP cells accounted for 0.2%-1.3%of the total human neuroblastoma cells and were decreased to 0.1%-0.5%after verapamil treatment.The SP and non-SP cells showed disparity in cell growth experiment and drug resistance to DDP.Oncogenicity experiment revealed that nude mice could erupt tumor by an injection of 1×10^(6)SH-SY5Y and WIV SP cells.However,the nude mice could not form tumor by an injection of 1×10^(6)non-SP cells.Conclusion:Neuroblastoma might contain cancer stem cell-like cells.
基金This work was supported by the National Key Research and Development Program of China(2017YFE0127600,2016YFA0202600)the Program of Introducing Talents of Discipline to Universities(B17034)+3 种基金the National Natural Science Foundation of China(51521001 and 51602239)the National Natural Science Fund for Distinguished Young Scholars(51425204)Hubei Provincial Natural Science Foundation(2016CFB267)the Fundamental Research Funds for the Central Universities(WUT:2017-YB-001).
文摘The low-cost and high-capacity metal oxides/oxyhydroxides possess great merits as anodes for lithium-ion batteries(LIBs)with high energy density.However,their commercialization is greatly hindered by insufficient rate capability and cyclability.Rational regulations of metal oxides/oxyhydroxides with hollow geometry and disordered atomic frameworks represent efficient ways to improve their electrochemical properties.Herein,we propose a fast alkalietching method to realize the in-situ fabrication of iron oxyhydroxide with one-dimensional(1D)hierarchical hollow nanostructure and amorphous atomic structure from the iron vanadate nanowires.Benefiting from the improved electron/ion kinetics and efficient buffer ability for the volumetric change during the electro-cycles both in nanoscale and atomic level,the graphene-modified amorphous hierarchical FeOOH nanotubes(FeOOH-NTs)display high rate capability(~650 mA h g^−1 at 2000 mA g^−1)and superior long-term cycling stability(463 mA h g^−1 after 1800 cycles),which represents the best cycling performance among the reported FeOOH-based materials.More importantly,the selective dissolutionregrowth mechanism is demonstrated based on the time tracking of the whole transition process,in which the dissolution of FeVO4 and the in-situ selective re-nucleation of FeOOH during the formation of FeOOH-NTs play the key roles.The present strategy is also a general method to prepare various metal(such as Fe,Mn,Co,and Cu)oxides/oxyhydroxides with 1D hierarchical nanostructures.