Breast cancer is the most common malignant tumor in Chinese women.Early screening is the best way to improve the rates of early diagnosis and survival of breast cancer patients.The peak onset age for breast cancer in ...Breast cancer is the most common malignant tumor in Chinese women.Early screening is the best way to improve the rates of early diagnosis and survival of breast cancer patients.The peak onset age for breast cancer in Chinese women is considerably younger than those in European and American women.It is imperative to develop breast cancer screening guideline that is suitable for Chinese women.By summarizing the current evidence on breast cancer screening in Chinese women,and referring to the latest guidelines and consensus on breast cancer screening in Europe,the United States,and East Asia,the China Anti-Cancer Association and National Clinical Research Center for Cancer(Tianjin Medical University Cancer Institute and Hospital)have formulated population-based guideline for breast cancer screening in Chinese women.The guideline provides recommendations on breast cancer screening for Chinese women at average or high risk of breast cancer according to the following three aspects:age of screening,screening methods,and screening interval.This article provides more detailed information to support the recommendations in this guideline and to provide more direction for current breast cancer screening practices in China.展开更多
Despite of suitable band structures for harvesting solar light and driving water redox reactions,polymeric carbon nitride(PCN)has suffered from poor charge transfer ability and sluggish surface reaction kinetics,which...Despite of suitable band structures for harvesting solar light and driving water redox reactions,polymeric carbon nitride(PCN)has suffered from poor charge transfer ability and sluggish surface reaction kinetics,which limit its photocatalytic activity for water splitting.Herein,atomically dispersed Zn-coordinated three-dimensional(3D)sponge-like PCN(Zn-PCN)is synthesized through a novel intermediate coordination strategy.Advanced characterizations and theoretical calculations well evidence that Zn single atoms are coordinated and stabilized on PCN in the form of Zn-N_(6) configura-tion featured with an electron-deficient state.Such an electronic configuration has been demonstrated contributive to promoted electron excitation,accelerated charge separation and transfer as well as reduced water redox barriers.Further benefited from the abundant surface active sites derived from the 3D porous structure,Zn-PCN realizes visible-light photocatalysis for overall water splitting with H_(2) and O_(2) simultaneously evolved at a stoichiometric ratio of 2:1.This work brings new insights into the design of novel single-atom photocatalysts by deepening the understanding of electronic configurations and reactive sites favorable to excellent photocatalysis for water splitting and related solar energy conversion reactions.展开更多
Development of a low-cost and durable bifunctional electrocatalyst with high catalytic activity by hybridizing rare earth metal and non-noble metal is of utmost significance.Herein,a bifunctional electrocatalyst consi...Development of a low-cost and durable bifunctional electrocatalyst with high catalytic activity by hybridizing rare earth metal and non-noble metal is of utmost significance.Herein,a bifunctional electrocatalyst consisting of MoO_(2)and CeO_(x)heterostructure is synthesized via interfacial engineering.Particularly,due to its unique hetero-interface with abundant oxygen vacancies,the MoO_(2)-CeO_(x)_(x)/NF is able to exhibit outstanding hydrogen evolution reaction(HER) performance with an overpotential of 26 mV at 10 mA cm^(-2),and a preferable oxygen evolution reaction(OER) overpotential of 272 mV at 100 mA cmin 1 M KOH.The recorded HER and OER overpotentials of MoO_(2)-CeO_(x)/NF are clearly smaller than those of Pt/C(HER overpotential of 27 mV) and RuO(OER overpotential of 393 mV) at the same current density.More importantly,MoO_(2)-CeO_(x)/NF can also exhibit good HER activity with an overpotential of 50 mV at 10 mA cmin acidic media.Thus,it is expected that this work can offer a new approach in the realization of high-catalytic alkaline overall water splitting and acidic HER performance through the rational design of rare-earth metal and non-noble metal heterostructure.展开更多
Leukoaraiosis(LA)results from ischemic injury in small cerebral vessels,which may be attributable to decreased vascular density,reduced cerebrovascular angiogenesis,decreased cerebral blood flow,or microcirculatory dy...Leukoaraiosis(LA)results from ischemic injury in small cerebral vessels,which may be attributable to decreased vascular density,reduced cerebrovascular angiogenesis,decreased cerebral blood flow,or microcirculatory dysfunction in the brain.In this study,we enrolled 357 patients with mild intracerebral hemorrhage(ICH)from five hospitals in China and analyzed the relationships between LA and clinical symptom severity at admission,neurological function prognosis at 3 months,and 1-year stroke recurrence.Patients were divided into groups based on Fazekas scale scores:no LA(n=83),mild LA(n=64),moderate LA(n=98)and severe LA(n=112).More severe LA,larger hematoma volume,and higher blood glucose level at admission were associated with more severe neurological deficit.More severe LA,older age and larger hematoma volume were associated with worse neurological function prognosis at 3 months.In addition,moderate-to-severe LA,admission glucose and symptom-free cerebral infarction were associated with 1-year stroke recurrence.These findings suggest that LA severity may be a potential marker of individual ICH vulnerability,which can be characterized by poor tolerance to intracerebral attack or poor recovery ability after ICH.Evaluating LA severity in patients with mild ICH may help neurologists to optimize treatment protocols.This study was approved by the Ethics Committee of Ruijin Hospital Affiliated to Shanghai Jiao Tong University(approval No.12)on March 10,2011.展开更多
In this study,complete tetracycline(TTC)and above 50%of total organic carbon(TOC)were removed by Fe S/PS after 30 min under optimized conditions.Although free radicals and high-valent iron ions were identified to gene...In this study,complete tetracycline(TTC)and above 50%of total organic carbon(TOC)were removed by Fe S/PS after 30 min under optimized conditions.Although free radicals and high-valent iron ions were identified to generate in the process,the apparent similarity between intermediate products of Fe S/PS,Fe/PS,and UV/PS systems demonstrated that the degradation of TTC was due to sulfate radicals(SO_(4)·^(-))and hydroxyl radicals(·OH).Based on the reaction between free radicals and organic matter,we speculated that TTC in the Fe S/PS system was decomposed and mineralized by dehydration,dehydrogenation,hydroxyl addition,demethylation,substitution,E-transfer,and ring-opening.Furthermore,a new understanding of Fe S-mediated PS activation based on stoichiometry and kinetic analysis showed that there were both homogeneous and heterogeneous reactions that occurred in the entire progress.However,due to the effect of p H on the dissolution of iron ions,the homogeneous reaction became the principal process with iron ions concentration exceeding 1.35 mg/L.This work provides a theoretical basis for the study of the degradation of TTC-containing wastewater by the iron-based advanced oxidation process.展开更多
LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy ...LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy densities at high operation voltage.However,the capacity fading under high operation voltage still restricts the practical application.Herein,the capacity degradation mechanism of NCM811 at atomic-scale is studied in detail under various cut-off voltages using aberration-corrected scanning transmission electron microscopy(STEM).It is observed that the crystal structure of NCM811 evolution from a layered structure to a rock-salt phase is directly accompanied by serious intergranular cracks under 4.9 V,which is distinguished from the generally accepted structure evolution of layered,disordered layered,defect rock salt and rock salt phases,also observed under 4.3 and 4.7 V.The electron energy loss spectroscopy analysis also confirms the reduction of Ni and Co from the surface to the bulk,not the previously reported only Li/Ni interlayer mixing.The degradation mechanism of NCM811 at a high cut-off voltage of4.9 V is attributed to the formation of intergranular cracks induced by defects,the direct formation of the rock salt phase,and the accompanied reduction of Ni^(2+)and Co^(2+)phases from the surface to the bulk.展开更多
Objective:This post-approval safety study assessed the efficacy and safety of exemestane after 2-3 years of tamoxifen treatment among postmenopausal women with estrogen receptor-positive(ER+)early breast cancer in Chi...Objective:This post-approval safety study assessed the efficacy and safety of exemestane after 2-3 years of tamoxifen treatment among postmenopausal women with estrogen receptor-positive(ER+)early breast cancer in China.Methods:Enrolled patients had received 2-3 years of tamoxifen and were then switched to exemestane for completion of 5 consecutive years of adjuvant endocrine therapy.The primary endpoint was the time from enrollment to the first occurrence of locoregional/distant recurrence of the primary breast cancer,appearance of a second primary or contralateral breast cancer,or death due to any cause.Other endpoints included the proportion of patients experiencing each event,incidence rate per annum,relationships between human epidermal growth factor receptor 2 status and time to event,and relationship between disease history variables and time to event.Results:Overall,558 patients were included in the full analysis set:397(71.1%)completed the study,20experienced an event,and 141 discontinued[47 owing to an adverse event(AE);37 no longer willing to participate].Median duration of treatment was 29.5(range,0.1-57.7)months.Median time to event was not reached.Eventfree survival probability at 36 months was 91.4%(95%CI,87.7%-95.1%).The event incidence over the total exposure time of exemestane therapy was 3.5 events/100 person-years(20/565).Multivariate analysis showed an association between tumor,lymph node,and metastasis stage at initial diagnosis and time to event[hazard ratio:1.532(95%CI,1.129-2.080);P=0.006].Most AEs were grade 1 or 2 in severity,with arthralgia(7.7%)being the most common treatment-related AE.Conclusions:This study supports the efficacy and safety of exemestane in postmenopausal Chinese women with ER+breast cancer previously treated with adjuvant tamoxifen for 2-3 years.No new safety signals were identified in the Chinese population.展开更多
Compared with female breast cancer, male breast cancer is a rare disease, and the relationship between clinical/pathologic features and prognosis is controversial, or even largely unknown. In this study, we performed ...Compared with female breast cancer, male breast cancer is a rare disease, and the relationship between clinical/pathologic features and prognosis is controversial, or even largely unknown. In this study, we performed a retrospective analysis using clinical and pathologic data from 109 nonmetastatic operable male breast cancer patients treated from January 1996 to December 2011 at Tianjin Medical University Cancer Institute and Hospital. Log-rank test showed that lower tumor stage, no lymph node involvement, and positive estrogen/progesterone receptor status were good predictors of both disease-free survival and overall survival on univariate analysis. However, hormonotherapy is only a good predictive factor of disease-free survival, and not of overall survival. In addition, based on a Cox proportional hazard regression model, only lymph node involvement, and estrogen/progesterone receptor status were statistically significant predictive factors on multivariate analysis. Our results demonstrated that although adjuvant systemic therapy is used extensively in male breast cancer patients and prognosis has improved over the last few decades, lymph node involvement, and estrogen/progesterone receptor status are still the most important prognostic factors. A prospective multi-center study with a larger sample size is urgently needed to further understand male breast cancer.展开更多
The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the ...The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.展开更多
Heterointerfaces have been pivotal in unveiling extraordinary interfacial properties and enabling multifunctional material platforms.Despite extensive research on all-oxide interfaces,heterointerfaces between differen...Heterointerfaces have been pivotal in unveiling extraordinary interfacial properties and enabling multifunctional material platforms.Despite extensive research on all-oxide interfaces,heterointerfaces between different material classes,such as oxides and nitrides,remain underexplored.Here we present the fabrication of atomically sharp heterointerfaces between antiperovskite Ni_(3)InN and perovskite SrVO_(3).Leveraging layer-resolved scanning transmission electron microscopy and electron energy loss spectroscopy,we identified pronounced charge transfer across the well-ordered interface.First-principles calculations confirmed our experimental observations and further predicted an emergent magnetic moment within the Ni_(3)InN layer due to the charge transfer.These findings pave the way for novel electronic and spintronic applications by enabling tunable interfacial properties in nitride/oxide systems.展开更多
Excessive nitrogen emission caused by human activities has significantly disrupted the global nitrogen cycle,adversely affecting ecosystems and human health.Electrocatalytic nitrate reduction to valuable ammonia(eNRA)...Excessive nitrogen emission caused by human activities has significantly disrupted the global nitrogen cycle,adversely affecting ecosystems and human health.Electrocatalytic nitrate reduction to valuable ammonia(eNRA)presents an encouraging alternative marked by mild reaction conditions,rapid reaction rates,and minimal byproduct pollution,successfully overcoming the challenges of the energy-intensive Haber-Bosch process.Recent innovations in two-dimensional(2D)electrocatalysts have emerged as a promising approach to enhance the efficiency and selectivity of this transformation.This review systematically examines the latest advancements in2D materials,including metals,metal compounds,nonmetallic elements,and organic frameworks,highlighting their unique electronic properties and high surface area that facilitate the electrocatalytic reactions.We explore strategies to optimize these catalysts,such as doping,heterostructure,and surface functionalization,which have shown significant improvements in catalytic performance.Furthermore,the role of in situ/operando characterization techniques in understanding the reaction mechanisms is highlighted,aiming to provide both theoretical and practical insights for the research and development of 2D nanoelectrocatalysts during eNRA.Additionally,future perspectives and ongoing challenges are discussed to offer insights for transitioning from experimental investigations to real-world applications.展开更多
Precipitation at grain boundaries is typically not regarded as an efficient method for strengthening materials since it can induce grain boundary embrittlement, which detrimentally affects ductility. In this research,...Precipitation at grain boundaries is typically not regarded as an efficient method for strengthening materials since it can induce grain boundary embrittlement, which detrimentally affects ductility. In this research, we developed a multi-principal element alloy (MPEA) with the composition Cr_(30)Co_(30)Ni_(30)Al_(5)Ti_(5) (at.%), incorporating both intragranular and intergranular nanoprecipitates. Utilizing multiscale, three-dimensional, and in-situ electron microscopy techniques, coupled with computational simulations, we established that intergranular nanoprecipitation in this material plays a crucial role in enhancing strength and promoting dislocation plasticity. The structure of intergranular nanoprecipitation comprises multiple phases with varying composition and structure. Despite the diversity, the crystal planes conducive to the easy glide of dislocations are well-matched, allowing for the sustained continuity of dislocation slipping across different phase structures. Simultaneously, this structure generates an undulated stress field near grain boundaries, amplifying the strengthening effect and facilitating multiple slip and cross-slip during deformation. Consequently, it promotes the proliferation and storage of dislocations. As a result, our material exhibits a yield strength of approximately 1010 MPa and an ultimate tensile strength of around 1500 MPa, accompanied by a significant fracture elongation of 41 %. Our findings illuminate the potential for harnessing intergranular nanoprecipitation to optimize the strength-ductility trade-off in MPEAs, emphasizing the strategy of leveraging complex compositions for the design of sophisticated functional microstructures.展开更多
Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity betw...Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity between F and O render the O/F site occupation and local lattice evolution during fluorination unclear.Here we investigated the atomic-scale O/F exchange in La2CoO4and quantified the lattice distortion of three ordered structures:La_(2)CoO_(3.5)F,La_(2)CoO_(3)F_(2),and La_(2)CoO_(2.5)F_(3)by utilizing aberration-corrected electron microscopy.Atomic-resolved elemental mapping provides direct evidence for the O/F occupancy in interstitial and apical sites.We revealed that apical F ions induce significant octahedral tilting from 178°to 165°,linearly proportional to the occupancy rate;and cause the obvious change in the fine structure O K edge,meanwhile apical O is exchanged into interstitial sites.The strong octahedral tilt leads to the in-plane elongation of the[CoO_(4)F_(2)]octahedra.These findings elucidate the atomic-scale mechanisms of the entire fluorination process and highlight the significant role of F in tuning the octahedral tilt of functional oxides.展开更多
通过电解水制备氢气是实现“碳中和”目标的理想途径之一.因此,可在全p H条件下使用的氢析出(HER)催化剂的研发是近年来电催化领域的研究热点.原子级分散的催化剂,能够在保留铂族金属(PGM)固有活性的同时,降低催化剂中PGM的用量.虽然可...通过电解水制备氢气是实现“碳中和”目标的理想途径之一.因此,可在全p H条件下使用的氢析出(HER)催化剂的研发是近年来电催化领域的研究热点.原子级分散的催化剂,能够在保留铂族金属(PGM)固有活性的同时,降低催化剂中PGM的用量.虽然可以通过X射线吸收光谱(XAS)来表征原子分散的PGM电催化剂的配位环境,但目前对原子空间分布的控制仍然具有挑战.本文制备了钒掺杂钨青铜内通道氨配位的钌单原子催化剂(Ru/V-NHWO),用于全p H范围内的HER反应.采用X射线衍射(XRD)、高角环形暗场扫描透射电镜(HAADF-STEM)、X射线光电子能谱(XPS)和原位X射线吸收光谱(XAS)等进行表征,研究了钌单原子与V-NHWO载体的结合方式以及构效关系,并采用密度泛函理论(DFT)计算探索了催化剂中诸多位点的活性贡献.在1 mol/LKOH, 0.5 mol/L H_(2)SO_(4)和1 mol/L磷酸盐缓冲溶液中,其在10 m Acm^(-2)下的过电位分别为28.0, 29.6和40.6 m V.同时,在过电位100 m V时,质量活性分别达到3930, 1941和602.8 m Amg^(-1)Ru,数倍于同等条件下的商业铂碳.XRD结果表明,钌的引入可以确保催化剂在氩气条件下热解后仍保持六方钨铵青铜晶相,证明钌与钨铵青铜六方晶体通道内氨物种,即“通道氨”的结合.HAADF-STEM结果表明,钌原子与NHWO间存在强烈相互作用,有助于提升HER性能.XPS和XAS结果表明, W5+信号出现在引入钌后,峰位置的结合能增加且峰面积降低,说明钌与通道氨之间存在相互作用.N的XPS结果表明,钌的引入导致了金属氨键的形成.XAS结果表明, Ru/V-NHWO/CC中钌单原子和钌团簇共存,钌单原子与通道氨配位,并且钒的引入会诱发V-NHWO中金属键长缩短,这表明催化剂的金属性得到了提升,有利于改善其导电性.采用DFT计算进一步研究了HER活性的来源.相比于V-NHWO载体和钌团簇修饰的V-NHWO,以单原子形式结合的钌具有更低的水解离能垒,该能垒在氨桥接的钌双原子垂直插入、钒掺杂和多通道插入等多种因素作用下进一步降低.同时,氢中间体结合能得到了相应的优化而趋近于0 e V.此外,差分电荷密度模拟结果表明,氢中间体结合后, V-NHWO对于钌单原子存在明显的供电子行为,有利于HER动力学过程.综上,本工作报道了金属载体对于高分散金属原子空间分布调控的重要作用,可为设计和构筑可应用于诸多能源转换过程的新型原子级分散催化剂提供参考.展开更多
Owing to the high spatial resolution at the atomic scale,the transmission electron microscopy(TEM)or scanning transmission electron microscopy is demonstrated as a promising characterization method to unveil the charg...Owing to the high spatial resolution at the atomic scale,the transmission electron microscopy(TEM)or scanning transmission electron microscopy is demonstrated as a promising characterization method to unveil the charge storage mechanism of electrode materials in Li-ion batteries.The structural evolution of electrode materials during charge/discharge process can be directly observed by using TEM.The detailed analysis establishes a relationship between the structure of electrode material and battery performance.Herein,we present a brief review of the atomic-scale characterization in Li-ion batteries,including Li(de)insertion mechanism(both cations and anions charge-compensation mechanism),migration of transition metal ions,and surface phase transition.The indepth microscopic analysis reveals the detailed structural characteristics,which influence the properties of LIBs,establish the structure-function relationship,and facilitate the development of Li-ion batteries.展开更多
An intrinsic magnetic topological insulator(TI) is a stoichiometric magnetic compound possessing both inherent magnetic order and topological electronic states. Such a material can provide a shortcut to various novel ...An intrinsic magnetic topological insulator(TI) is a stoichiometric magnetic compound possessing both inherent magnetic order and topological electronic states. Such a material can provide a shortcut to various novel topological quantum effects but remained elusive experimentally for a long time. Here we report the experimental realization of thin films of an intrinsic magnetic TI, MnBi2Te4, by alternate growth of a Bi2Te3 quintuple layer and a MnTe bilayer with molecular beam epitaxy. The material shows the archetypical Dirac surface states in angle-resolved photoemission spectroscopy and is demonstrated to be an antiferromagnetic topological insulator with ferromagnetic surfaces by magnetic and transport measurements as well as first-principles calculations. The unique magnetic and topological electronic structures and their interplays enable the material to embody rich quantum phases such as quantum anomalous Hall insulators and axion insulators at higher temperature and in a well-controlled way.展开更多
基金supported by National Key Technology Support Program (Grant No. 2015BAI12B15)
文摘Breast cancer is the most common malignant tumor in Chinese women.Early screening is the best way to improve the rates of early diagnosis and survival of breast cancer patients.The peak onset age for breast cancer in Chinese women is considerably younger than those in European and American women.It is imperative to develop breast cancer screening guideline that is suitable for Chinese women.By summarizing the current evidence on breast cancer screening in Chinese women,and referring to the latest guidelines and consensus on breast cancer screening in Europe,the United States,and East Asia,the China Anti-Cancer Association and National Clinical Research Center for Cancer(Tianjin Medical University Cancer Institute and Hospital)have formulated population-based guideline for breast cancer screening in Chinese women.The guideline provides recommendations on breast cancer screening for Chinese women at average or high risk of breast cancer according to the following three aspects:age of screening,screening methods,and screening interval.This article provides more detailed information to support the recommendations in this guideline and to provide more direction for current breast cancer screening practices in China.
基金This work was supported by the National Key Research and Development Program of China(2018YFB1502003)the National Natural Science Foundation of China(52225606,21875183,52172248)+2 种基金the“Fundamental Research Funds for the Central Universities”the Natural Science Basic Research Program of Shaanxi Province(2019JCW-10)“The Youth Innovation Team of Shaanxi Universities”.
文摘Despite of suitable band structures for harvesting solar light and driving water redox reactions,polymeric carbon nitride(PCN)has suffered from poor charge transfer ability and sluggish surface reaction kinetics,which limit its photocatalytic activity for water splitting.Herein,atomically dispersed Zn-coordinated three-dimensional(3D)sponge-like PCN(Zn-PCN)is synthesized through a novel intermediate coordination strategy.Advanced characterizations and theoretical calculations well evidence that Zn single atoms are coordinated and stabilized on PCN in the form of Zn-N_(6) configura-tion featured with an electron-deficient state.Such an electronic configuration has been demonstrated contributive to promoted electron excitation,accelerated charge separation and transfer as well as reduced water redox barriers.Further benefited from the abundant surface active sites derived from the 3D porous structure,Zn-PCN realizes visible-light photocatalysis for overall water splitting with H_(2) and O_(2) simultaneously evolved at a stoichiometric ratio of 2:1.This work brings new insights into the design of novel single-atom photocatalysts by deepening the understanding of electronic configurations and reactive sites favorable to excellent photocatalysis for water splitting and related solar energy conversion reactions.
基金financially supported by the National Natural Science Foundation of China (No. 22065015)Key Research Program of Jiangxi Province of China (No. 20202BBEL53023)。
文摘Development of a low-cost and durable bifunctional electrocatalyst with high catalytic activity by hybridizing rare earth metal and non-noble metal is of utmost significance.Herein,a bifunctional electrocatalyst consisting of MoO_(2)and CeO_(x)heterostructure is synthesized via interfacial engineering.Particularly,due to its unique hetero-interface with abundant oxygen vacancies,the MoO_(2)-CeO_(x)_(x)/NF is able to exhibit outstanding hydrogen evolution reaction(HER) performance with an overpotential of 26 mV at 10 mA cm^(-2),and a preferable oxygen evolution reaction(OER) overpotential of 272 mV at 100 mA cmin 1 M KOH.The recorded HER and OER overpotentials of MoO_(2)-CeO_(x)/NF are clearly smaller than those of Pt/C(HER overpotential of 27 mV) and RuO(OER overpotential of 393 mV) at the same current density.More importantly,MoO_(2)-CeO_(x)/NF can also exhibit good HER activity with an overpotential of 50 mV at 10 mA cmin acidic media.Thus,it is expected that this work can offer a new approach in the realization of high-catalytic alkaline overall water splitting and acidic HER performance through the rational design of rare-earth metal and non-noble metal heterostructure.
基金supported by the National Natural Science Foundation of China,Nos.81771281(to FXS),81471177(to FXS)the Natural Science Foundation of Shanghai of China,No.20ZR1434200(to YF)。
文摘Leukoaraiosis(LA)results from ischemic injury in small cerebral vessels,which may be attributable to decreased vascular density,reduced cerebrovascular angiogenesis,decreased cerebral blood flow,or microcirculatory dysfunction in the brain.In this study,we enrolled 357 patients with mild intracerebral hemorrhage(ICH)from five hospitals in China and analyzed the relationships between LA and clinical symptom severity at admission,neurological function prognosis at 3 months,and 1-year stroke recurrence.Patients were divided into groups based on Fazekas scale scores:no LA(n=83),mild LA(n=64),moderate LA(n=98)and severe LA(n=112).More severe LA,larger hematoma volume,and higher blood glucose level at admission were associated with more severe neurological deficit.More severe LA,older age and larger hematoma volume were associated with worse neurological function prognosis at 3 months.In addition,moderate-to-severe LA,admission glucose and symptom-free cerebral infarction were associated with 1-year stroke recurrence.These findings suggest that LA severity may be a potential marker of individual ICH vulnerability,which can be characterized by poor tolerance to intracerebral attack or poor recovery ability after ICH.Evaluating LA severity in patients with mild ICH may help neurologists to optimize treatment protocols.This study was approved by the Ethics Committee of Ruijin Hospital Affiliated to Shanghai Jiao Tong University(approval No.12)on March 10,2011.
基金supported by the National Natural Science Foundation of China(No.21876130)Natural Science Foundation of Shanghai(No.18ZR1440800)。
文摘In this study,complete tetracycline(TTC)and above 50%of total organic carbon(TOC)were removed by Fe S/PS after 30 min under optimized conditions.Although free radicals and high-valent iron ions were identified to generate in the process,the apparent similarity between intermediate products of Fe S/PS,Fe/PS,and UV/PS systems demonstrated that the degradation of TTC was due to sulfate radicals(SO_(4)·^(-))and hydroxyl radicals(·OH).Based on the reaction between free radicals and organic matter,we speculated that TTC in the Fe S/PS system was decomposed and mineralized by dehydration,dehydrogenation,hydroxyl addition,demethylation,substitution,E-transfer,and ring-opening.Furthermore,a new understanding of Fe S-mediated PS activation based on stoichiometry and kinetic analysis showed that there were both homogeneous and heterogeneous reactions that occurred in the entire progress.However,due to the effect of p H on the dissolution of iron ions,the homogeneous reaction became the principal process with iron ions concentration exceeding 1.35 mg/L.This work provides a theoretical basis for the study of the degradation of TTC-containing wastewater by the iron-based advanced oxidation process.
基金supported by the National Natural Science Foundation of China(U2032131)the Key R&D Program of Shaanxi Province(2021GY-118)the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(2022SX-TD012 and 2021SXTD012)。
文摘LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy densities at high operation voltage.However,the capacity fading under high operation voltage still restricts the practical application.Herein,the capacity degradation mechanism of NCM811 at atomic-scale is studied in detail under various cut-off voltages using aberration-corrected scanning transmission electron microscopy(STEM).It is observed that the crystal structure of NCM811 evolution from a layered structure to a rock-salt phase is directly accompanied by serious intergranular cracks under 4.9 V,which is distinguished from the generally accepted structure evolution of layered,disordered layered,defect rock salt and rock salt phases,also observed under 4.3 and 4.7 V.The electron energy loss spectroscopy analysis also confirms the reduction of Ni and Co from the surface to the bulk,not the previously reported only Li/Ni interlayer mixing.The degradation mechanism of NCM811 at a high cut-off voltage of4.9 V is attributed to the formation of intergranular cracks induced by defects,the direct formation of the rock salt phase,and the accompanied reduction of Ni^(2+)and Co^(2+)phases from the surface to the bulk.
文摘Objective:This post-approval safety study assessed the efficacy and safety of exemestane after 2-3 years of tamoxifen treatment among postmenopausal women with estrogen receptor-positive(ER+)early breast cancer in China.Methods:Enrolled patients had received 2-3 years of tamoxifen and were then switched to exemestane for completion of 5 consecutive years of adjuvant endocrine therapy.The primary endpoint was the time from enrollment to the first occurrence of locoregional/distant recurrence of the primary breast cancer,appearance of a second primary or contralateral breast cancer,or death due to any cause.Other endpoints included the proportion of patients experiencing each event,incidence rate per annum,relationships between human epidermal growth factor receptor 2 status and time to event,and relationship between disease history variables and time to event.Results:Overall,558 patients were included in the full analysis set:397(71.1%)completed the study,20experienced an event,and 141 discontinued[47 owing to an adverse event(AE);37 no longer willing to participate].Median duration of treatment was 29.5(range,0.1-57.7)months.Median time to event was not reached.Eventfree survival probability at 36 months was 91.4%(95%CI,87.7%-95.1%).The event incidence over the total exposure time of exemestane therapy was 3.5 events/100 person-years(20/565).Multivariate analysis showed an association between tumor,lymph node,and metastasis stage at initial diagnosis and time to event[hazard ratio:1.532(95%CI,1.129-2.080);P=0.006].Most AEs were grade 1 or 2 in severity,with arthralgia(7.7%)being the most common treatment-related AE.Conclusions:This study supports the efficacy and safety of exemestane in postmenopausal Chinese women with ER+breast cancer previously treated with adjuvant tamoxifen for 2-3 years.No new safety signals were identified in the Chinese population.
基金ACKNOWLEDGMENTS This study was supported by the National Natural Science Foundation of China （Grants 81472683 and 81202275）, Tianjin Natural Science fund （Grant 13JCQNJC 11000） and Research Seed Foundation of Tianjin Medical University Gancer Hospital and Institute （Grant 1421）.
文摘Compared with female breast cancer, male breast cancer is a rare disease, and the relationship between clinical/pathologic features and prognosis is controversial, or even largely unknown. In this study, we performed a retrospective analysis using clinical and pathologic data from 109 nonmetastatic operable male breast cancer patients treated from January 1996 to December 2011 at Tianjin Medical University Cancer Institute and Hospital. Log-rank test showed that lower tumor stage, no lymph node involvement, and positive estrogen/progesterone receptor status were good predictors of both disease-free survival and overall survival on univariate analysis. However, hormonotherapy is only a good predictive factor of disease-free survival, and not of overall survival. In addition, based on a Cox proportional hazard regression model, only lymph node involvement, and estrogen/progesterone receptor status were statistically significant predictive factors on multivariate analysis. Our results demonstrated that although adjuvant systemic therapy is used extensively in male breast cancer patients and prognosis has improved over the last few decades, lymph node involvement, and estrogen/progesterone receptor status are still the most important prognostic factors. A prospective multi-center study with a larger sample size is urgently needed to further understand male breast cancer.
基金supported by the National Key R&D Program of China(No.2022YFB2404400)the National Natural Science Foundation of China(Nos.U23A20577,52372168,92263206 and 21975006)+1 种基金the“The Youth Beijing Scholars program”(No.PXM2021_014204_000023)the Beijing Natural Science Foundation(Nos.2222001 and KM202110005009).
文摘The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.
基金supported by the Beijing Natural Science Foundation(Grant No.JQ24002)the National Key Basic Research Program of China(Grant No.2020YFA0309100)+3 种基金the National Natural Science Foundation of China(Grant Nos.U22A20263,52250308,12304158,12325401,12274069,12404102,and 12474096)the Chinese Academy of Sciences(CAS)Project for Young Scientists in Basic Research(Grant No.YSBR-084)the CAS Youth Interdisciplinary Team,the Guangdong Basic and Applied Basic Research Foundation(Grant No.2022B1515120014)the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology,and the International Young Scientist Fellowship of Institute of Physics,CAS.
文摘Heterointerfaces have been pivotal in unveiling extraordinary interfacial properties and enabling multifunctional material platforms.Despite extensive research on all-oxide interfaces,heterointerfaces between different material classes,such as oxides and nitrides,remain underexplored.Here we present the fabrication of atomically sharp heterointerfaces between antiperovskite Ni_(3)InN and perovskite SrVO_(3).Leveraging layer-resolved scanning transmission electron microscopy and electron energy loss spectroscopy,we identified pronounced charge transfer across the well-ordered interface.First-principles calculations confirmed our experimental observations and further predicted an emergent magnetic moment within the Ni_(3)InN layer due to the charge transfer.These findings pave the way for novel electronic and spintronic applications by enabling tunable interfacial properties in nitride/oxide systems.
基金supported by the National Natural Science Foundation of China(Nos.52172291,52122312,and 52473294)'Shuguang Program'supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.22SG31)the State Key Laboratory for Advanced Fiber Materials,Donghua University
文摘Excessive nitrogen emission caused by human activities has significantly disrupted the global nitrogen cycle,adversely affecting ecosystems and human health.Electrocatalytic nitrate reduction to valuable ammonia(eNRA)presents an encouraging alternative marked by mild reaction conditions,rapid reaction rates,and minimal byproduct pollution,successfully overcoming the challenges of the energy-intensive Haber-Bosch process.Recent innovations in two-dimensional(2D)electrocatalysts have emerged as a promising approach to enhance the efficiency and selectivity of this transformation.This review systematically examines the latest advancements in2D materials,including metals,metal compounds,nonmetallic elements,and organic frameworks,highlighting their unique electronic properties and high surface area that facilitate the electrocatalytic reactions.We explore strategies to optimize these catalysts,such as doping,heterostructure,and surface functionalization,which have shown significant improvements in catalytic performance.Furthermore,the role of in situ/operando characterization techniques in understanding the reaction mechanisms is highlighted,aiming to provide both theoretical and practical insights for the research and development of 2D nanoelectrocatalysts during eNRA.Additionally,future perspectives and ongoing challenges are discussed to offer insights for transitioning from experimental investigations to real-world applications.
基金supported by the National Science Fund for Distinguished Young Scholars of China(No.52325102)the Natural Science Foundation of Zhejiang Province,China(No.LZ22E010001)the National Key R&D Program of China(No.2023YFB2405802).
文摘Precipitation at grain boundaries is typically not regarded as an efficient method for strengthening materials since it can induce grain boundary embrittlement, which detrimentally affects ductility. In this research, we developed a multi-principal element alloy (MPEA) with the composition Cr_(30)Co_(30)Ni_(30)Al_(5)Ti_(5) (at.%), incorporating both intragranular and intergranular nanoprecipitates. Utilizing multiscale, three-dimensional, and in-situ electron microscopy techniques, coupled with computational simulations, we established that intergranular nanoprecipitation in this material plays a crucial role in enhancing strength and promoting dislocation plasticity. The structure of intergranular nanoprecipitation comprises multiple phases with varying composition and structure. Despite the diversity, the crystal planes conducive to the easy glide of dislocations are well-matched, allowing for the sustained continuity of dislocation slipping across different phase structures. Simultaneously, this structure generates an undulated stress field near grain boundaries, amplifying the strengthening effect and facilitating multiple slip and cross-slip during deformation. Consequently, it promotes the proliferation and storage of dislocations. As a result, our material exhibits a yield strength of approximately 1010 MPa and an ultimate tensile strength of around 1500 MPa, accompanied by a significant fracture elongation of 41 %. Our findings illuminate the potential for harnessing intergranular nanoprecipitation to optimize the strength-ductility trade-off in MPEAs, emphasizing the strategy of leveraging complex compositions for the design of sophisticated functional microstructures.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52322212,52025025,5225040212474001)the National Key R&D Program of China(Grant Nos.2022YFA1403203 and 2023YFA1406300)。
文摘Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity between F and O render the O/F site occupation and local lattice evolution during fluorination unclear.Here we investigated the atomic-scale O/F exchange in La2CoO4and quantified the lattice distortion of three ordered structures:La_(2)CoO_(3.5)F,La_(2)CoO_(3)F_(2),and La_(2)CoO_(2.5)F_(3)by utilizing aberration-corrected electron microscopy.Atomic-resolved elemental mapping provides direct evidence for the O/F occupancy in interstitial and apical sites.We revealed that apical F ions induce significant octahedral tilting from 178°to 165°,linearly proportional to the occupancy rate;and cause the obvious change in the fine structure O K edge,meanwhile apical O is exchanged into interstitial sites.The strong octahedral tilt leads to the in-plane elongation of the[CoO_(4)F_(2)]octahedra.These findings elucidate the atomic-scale mechanisms of the entire fluorination process and highlight the significant role of F in tuning the octahedral tilt of functional oxides.
文摘通过电解水制备氢气是实现“碳中和”目标的理想途径之一.因此,可在全p H条件下使用的氢析出(HER)催化剂的研发是近年来电催化领域的研究热点.原子级分散的催化剂,能够在保留铂族金属(PGM)固有活性的同时,降低催化剂中PGM的用量.虽然可以通过X射线吸收光谱(XAS)来表征原子分散的PGM电催化剂的配位环境,但目前对原子空间分布的控制仍然具有挑战.本文制备了钒掺杂钨青铜内通道氨配位的钌单原子催化剂(Ru/V-NHWO),用于全p H范围内的HER反应.采用X射线衍射(XRD)、高角环形暗场扫描透射电镜(HAADF-STEM)、X射线光电子能谱(XPS)和原位X射线吸收光谱(XAS)等进行表征,研究了钌单原子与V-NHWO载体的结合方式以及构效关系,并采用密度泛函理论(DFT)计算探索了催化剂中诸多位点的活性贡献.在1 mol/LKOH, 0.5 mol/L H_(2)SO_(4)和1 mol/L磷酸盐缓冲溶液中,其在10 m Acm^(-2)下的过电位分别为28.0, 29.6和40.6 m V.同时,在过电位100 m V时,质量活性分别达到3930, 1941和602.8 m Amg^(-1)Ru,数倍于同等条件下的商业铂碳.XRD结果表明,钌的引入可以确保催化剂在氩气条件下热解后仍保持六方钨铵青铜晶相,证明钌与钨铵青铜六方晶体通道内氨物种,即“通道氨”的结合.HAADF-STEM结果表明,钌原子与NHWO间存在强烈相互作用,有助于提升HER性能.XPS和XAS结果表明, W5+信号出现在引入钌后,峰位置的结合能增加且峰面积降低,说明钌与通道氨之间存在相互作用.N的XPS结果表明,钌的引入导致了金属氨键的形成.XAS结果表明, Ru/V-NHWO/CC中钌单原子和钌团簇共存,钌单原子与通道氨配位,并且钒的引入会诱发V-NHWO中金属键长缩短,这表明催化剂的金属性得到了提升,有利于改善其导电性.采用DFT计算进一步研究了HER活性的来源.相比于V-NHWO载体和钌团簇修饰的V-NHWO,以单原子形式结合的钌具有更低的水解离能垒,该能垒在氨桥接的钌双原子垂直插入、钒掺杂和多通道插入等多种因素作用下进一步降低.同时,氢中间体结合能得到了相应的优化而趋近于0 e V.此外,差分电荷密度模拟结果表明,氢中间体结合后, V-NHWO对于钌单原子存在明显的供电子行为,有利于HER动力学过程.综上,本工作报道了金属载体对于高分散金属原子空间分布调控的重要作用,可为设计和构筑可应用于诸多能源转换过程的新型原子级分散催化剂提供参考.
基金financially supported by the National Natural Science Foundation of China(Nos.51672307 and 51421002)the Strategic Priority Research Program of Chinese Academy of Sciences(CAS)(No.XDB07030200)the Key Research Program of Frontier Sciences,CAS(No.QYZDB-SSWJSC035).
文摘Owing to the high spatial resolution at the atomic scale,the transmission electron microscopy(TEM)or scanning transmission electron microscopy is demonstrated as a promising characterization method to unveil the charge storage mechanism of electrode materials in Li-ion batteries.The structural evolution of electrode materials during charge/discharge process can be directly observed by using TEM.The detailed analysis establishes a relationship between the structure of electrode material and battery performance.Herein,we present a brief review of the atomic-scale characterization in Li-ion batteries,including Li(de)insertion mechanism(both cations and anions charge-compensation mechanism),migration of transition metal ions,and surface phase transition.The indepth microscopic analysis reveals the detailed structural characteristics,which influence the properties of LIBs,establish the structure-function relationship,and facilitate the development of Li-ion batteries.
基金Supported by the Ministry of Science and Technology of Chinathe National Science Foundation of Chinathe Beijing Advanced Innovation Center for Future Chip(ICFC)
文摘An intrinsic magnetic topological insulator(TI) is a stoichiometric magnetic compound possessing both inherent magnetic order and topological electronic states. Such a material can provide a shortcut to various novel topological quantum effects but remained elusive experimentally for a long time. Here we report the experimental realization of thin films of an intrinsic magnetic TI, MnBi2Te4, by alternate growth of a Bi2Te3 quintuple layer and a MnTe bilayer with molecular beam epitaxy. The material shows the archetypical Dirac surface states in angle-resolved photoemission spectroscopy and is demonstrated to be an antiferromagnetic topological insulator with ferromagnetic surfaces by magnetic and transport measurements as well as first-principles calculations. The unique magnetic and topological electronic structures and their interplays enable the material to embody rich quantum phases such as quantum anomalous Hall insulators and axion insulators at higher temperature and in a well-controlled way.
