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Fe-N-C core-shell catalysts with single low-spin Fe(Ⅱ)-N_(4)species for oxygen reduction reaction and high-performance proton exchange membrane fuel cells

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Journal of Energy Chemistry 2024年第6期93卷 538-546,I0013页

作者： Yan Wan linhui Yu Bingxin Yang Caihong li Chen fang Wei Guo fang-Xing Xiao Yangming lin Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen 361021FujianChina CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021FujianChina Fujian Institute of Research on the Structure of Matter Chinese Academy of SciencesFuzhou 350002FujianChina College of Materials Science and Engineering Fuzhou UniversityNew CampusMinhou 350108FujianChina College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117FujianChina

Fe-N-doped carbon materials(Fe-N-C)are promising candidates for oxygen reduction reaction(ORR)relative to Pt-based catalysts in proton exchange membrane fuel cells(PEMFCs).However,the intrinsic contributions of Fe-N_(4)moiety with different chemical/spin states(e.g.D1,D2,D3)to ORR are unclear since various states coexist *** the present work,Fe-N-C core-shell nanocatalyst with single lowspin Fe(Ⅱ)-N_(4)species(D1)is synthesized and identified with ex-situ ultralow temperature Mossbauer spectroscopy(T=1.6 K)that could essentially differentiate various Fe-N_(4)states and invisible Fe-O *** quantifying with CO-pulse chemisorption,site density and turnover frequency of Fe-N-C catalysts reach 2.4×10^(-9)site g^(-1)and 23 e site~(-1)s^(-1)during the ORR,***-wave potential(0.915V_(RHE))of the Fe-N-C catalyst is more positive(approximately 54 mV)than that of Pt/***,we observe that the performance of PEMFCs on Fe-N-C almost achieves the 2025 target of the US department of Energy by demonstrating a current density of 1.037 A cm^(-2)combined with the peak power density of 0,685 W cm^(-2),suggesting the critical role of Fe(Ⅱ)-N_(4)site(D1).After 500 h of running,PEMFCs still deliver a power density of 1.26 W cm^(-2)at 1.0 bar H_(2)-O_(2),An unexpected rate-determining step is figured out by isotopic labelling experiment and theoretical *** work not only offers valuable insights regarding the intrinsic contribution of Fe-N_(4)with a single spin state to alkaline/acidic ORR,but also provides great opportunities for developing high-performance stable PEMFCs.

关键词： Fuel cells Oxygen reduction reaction Non-platinum group metals(PGMs) Isotopic labelling Active site TOF

On implications of somatostatin in diabetic retinopathy

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Neural Regeneration Research 2024年第9期19卷 1984-1990页

作者： Yanhong fang Qionghua Wang Youjian li li Zeng Jian liu Kepeng Ou department of Ophthalmology Chongqing University Jiangjin HospitalChongqingChina College of Pharmacy National&Local Joint Engineering Research Center of Targeted and Innovative TherapeuticsIATTIChongqing University of Arts and SciencesChongqingChina Shandong Provincial Hospital Shandong Laboratory Animal CenterScience and Technology Innovation CenterShandong First Medical University&Shandong Academy of Medical SciencesJinanShandong ProvinceChina Academic Unit of Ophthalmology Bristol Medical SchoolUniversity of BristolBristolUK

Somatostatin,a naturally produced neuroprotective peptide,depresses excitatory neurotransmission and exerts anti-proliferative and anti-inflammatory effects on the *** this review,we summarize the progress of somatostatin treatment of diabetic retinopathy through analysis of relevant studies published from February 2019 to February 2023 extracted from the PubMed and Google Scholar *** neuroprotection,which occurs as a consequence of declined expression or dysregulation of retinal somatostatin in the very early stages of diabetic retinopathy,triggers retinal neurovascular unit impairment and microvascular *** replacement is a promising treatment for retinal neurodegeneration in diabetic *** pre-clinical and clinical trials of somatostatin analog treatment for early diabetic retinopathy have been *** one such trial(EUROCONDOR),topical administration of somatostatin was found to exert neuroprotective effects in patients with pre-existing retinal neurodysfunction,but had no impact on the onset of diabetic ***,we concluded that somatostatin restoration may be especially beneficial for the growing population of patients with early-stage *** order to achieve early prevention of diabetic retinopathy initiation,and thereby salvage visual function before the appearance of moderate non-proliferative diabetic retinopathy,several issues need to be *** include the needs to:a)update and standardize the retinal screening scheme to incorporate the detection of early neurodegeneration,b)identify patient subgroups who would benefit from somatostatin analog supplementation,c)elucidate the interactions of somatostatin,particularly exogenously-delivered somatostatin analogs,with other retinal peptides in the context of hyperglycemia,and d)design safe,feasible,low cost,and effective administration routes.

关键词： diabetes retinopathy excitotoxicity growth hormone insulin like growth factor irisin neurodegeneration neuroinflammation neuroprotection neurovascular unit octreotide oxidative stress somatostatin

Dynamic Resistance and Energy Absorption of Sandwich Beam via a Micro-Topology Optimization

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 146-162页

作者： Shiqiang li Yuwei li Xiaomin Ma Jianguang fang Zhifang liu Zhihua Wang Institute of Applied mechanics Taiyuan University of TechnologyTaiyuan 030024China Shanxi Key Laboratory of Material Strength and Structural Impact Taiyuan University of TechnologyTaiyuan 030024China School of Civil and Environmental Engineering University of Technology SydneySydneyNSW 2007Australia

The current research of sandwich structures under dynamic loading mainly focus on the response characteristic of *** micro-topology of core layers would sufficiently influence the property of sandwich ***,the micro deformation and topology mechanism of structural deformation and energy absorption are *** this paper,based on the bi-directional evolutionary structural optimization method and periodic base cell(PBC)technology,a topology optimization frame work is proposed to optimize the core layer of sandwich *** objective of the present optimization problem is to maximize shear stiffness of PBC with a volume *** effects of the volume fraction,filter radius,and initial PBC aspect ratio on the micro-topology of the core were *** dynamic response process,core compression,and energy absorption capacity of the sandwich beams under blast impact loading were analyzed by the finite element *** results demonstrated that the overpressure action stage was coupled with the core compression *** the same loading and mass per unit area,the sandwich beam with a 20%volume fraction core layer had the best blast *** filter radius has a slight effect on the shear stiffness and blast resistances of the sandwich *** increasing the filter radius could slightly improve the bending *** changing the initial PBC aspect ratio,there are three ways for PBC evolution:The first is to change the angle between the adjacent bars,the second is to further form holes in the bars,and the third is to combine the first two ***,not all three ways can improve the energy absorption capacity of the *** the aspect ratio of the PBC arbitrarily may lead to worse *** studies are necessary for further detailed *** research proposes a new topology sandwich beam structure by micro-topology optimization,which has sufficient shear *** micro mechanism of structural

关键词： Topology optimization Sandwich beam Impact loading Dynamic resistance Energy absorption Micro mechanism

Biomimetic artificial islet model with vascularized microcapsule structures for durable glycemic control

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Materials Futures 2024年第3期3卷 157-167页

作者： Jingbo li Yile fang Zhuhao Wu Luoran Shang ling li department of Endocrinology Zhongda HospitalSchool of MedicineSoutheast UniversityNanjing 210009People’s Republic of China Institute of Glucose and lipid Metabolism Southeast UniversityNanjing 210009People’s Republic of China Shanghai Xuhui Central Hospital Zhongshan-Xuhui Hospitaland the Shanghai Key Laboratory of Medical EpigeneticsThe International Co-laboratory of Medical Epigenetics and Metabolism(Ministry of Science and Technology)Institutes of Biomedical SciencesFudan UniversityShanghai 200032People’s Republic of China department of Clinical Laboratory Nanjing Drum Tower HospitalThe Affiliated of Medical SchoolNanjing UniversityNanjing 210008People’s Republic of China

Islet transplantation is a promising strategy for diabetes mellitus treatment as it can recapitulate endogenous insulin secretion and provide long-term glycemic *** models constructed in biomaterial scaffolds that reproduce biological characteristics of native islets is a feasible option to circumvent the dilemma of donor shortage and the requirement of chronic ***,we developed bioinspired artificial microcapsule-based islet models with microvessels for glycemic control using microfluidic electrospray *** electrospray can generate uniform hydrogel microcapsules with core-shell structure for encapsulating islet *** cell-laden microcapsules enabled the efficient transportation of nutrient,oxygen,and insulin;as well as the incorporation with microvessels for prompting glucose responsiveness and molecular *** demonstrated by in vivo experiments that the blood glucose,food intake,and body weight of diabetic mouse models were alleviated,and the glucose tolerance was promoted after the engraftment of islet *** further demonstrated the improved functionality of transplanted islet model in insulin secretion,immune escape,and microcirculation using standard histological and molecular *** results indicated that the microcapsules with microvessels are promising artificial islet models and are valuable for treating diabetes.

关键词： artificial islet model microfluidics vascularization hydrogel diabetes

Tissue adhesive,ROS scavenging and injectable PRP-based‘plasticine’for promoting cartilage repair

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Regenerative Biomaterials 2024年第1期3卷 94-107页

作者： Shiao li Dawei Niu Haowei fang Yancheng Chen Jinyan li Kunxi Zhang Jingbo Yin Peiliang Fu department of Orthopedics Shanghai Changzheng HospitalNaval Medical UniversityShanghai 200003P.R.China department of Polymer Materials School of Materials Science and EngineeringShanghai UniversityShanghai 200444P.R.China

Platelet-rich plasma(PRP)that has various growth factors has been used clinically in cartilage ***,the short residence time and release time at the injury site limit its therapeutic *** present study fabricated a granular hydrogel that was assembled from gelatin microspheres and tannic acid through their abundant hydrogen *** microspheres with the gelatin concentration of 10wt%and the diameter distribution of 1-10 lm were used to assemble by tannic acid to form the granular hydrogel,which exhibited elasticity under low shear strain,but flowability under higher shear *** viscosity decreased with the increase in shear ***,the granular hydrogel exhibited self-healing feature during rheology ***,granular hydrogel carrying PRP not only exhibited well-performed injectability but also performed like a‘plasticine’that possessed good *** granular hydrogel showed tissue adhesion ability and reactive oxygen species scavenging *** hydrogel carrying PRP transplanted to full-thickness articular cartilage defects could integrate well with native cartilage,resulting in newly formed cartilage articular fully filled in defects and well-integrated with the native cartilage and subchondral *** unique features of the present granular hydrogel,including injectability,plasticity,porous structure,tissue adhesion and reactive oxygen species scavenging provided an ideal PRP carrier toward cartilage tissue engineering.

关键词： cartilage regeneration granular hydrogel gelatin tannic acid PRP

Simultaneous detection of flare-associated kink oscillations and extreme-ultraviolet waves

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Science china(Technological Sciences) 2024年第5期67卷 1592-1601页

作者： li Dong HOU ZhenYong BAI XianYong li Chuan fang Matthew ZHAO HaiSheng WANG JinCheng NING ZongJun Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing210023China Yunnan Key Laboratory of the Solar Physics and Space Science Kunming650216China School of Earth and Space Sciences Peking UniversityBeijing100871China National Astronomical Observatories Chinese Academy of SciencesBeijing100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing100049China School of Astronomy and Space Science Nanjing UniversityNanjing210023China Key Laboratory of Modern Astronomy and Astrophysics Ministry of EducationNanjing UniversityNanjing210023China Columbus Academy GahannaOhio43230USA Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China Yunnan Observatories Chinese Academy of SciencesKunming650216China

Kink oscillations,which are frequently observed in coronal loops and prominences,are often accompanied by extreme-ultraviolet(EUV)***,much more needs to be explored regarding the causal relationships between kink oscillations and EUV *** this article,we report the simultaneous detection of kink oscillations and EUV waves that are both associated with an X2.1 flare on 2023 March 03(SOL2023-03-03T17:39).The kink oscillations,which are almost perpendicular to the axes of loop-like structures,are observed in three coronal loops and one *** short loop shows in-phase oscillation within the same period of 5.2 min at three *** oscillation could be triggered by the pushing of an expanding loop and interpreted as the standing kink *** lags are found between the kink oscillations of the short loop and two long loops,suggesting that the kink wave travels in different *** kink oscillations of one long loop and the prominence are possibly driven by the disturbance of the coronal mass ejection(CME),and that of another long loop might be attributed to the interaction of the EUV *** onset time of the kink oscillation of the short loop is nearly same as the beginning of an EUV *** fact demonstrates that they are almost *** EUV wave is most likely excited by the expanding loop structure and shows two *** leading component is a fast coronal wave,and the trailing one could be due to the stretching magnetic field lines.

关键词： coronal loops solar flares solar prominence solar oscillations extreme-ultraviolet wave magnetohydrodynamic

Newtonian limit of Einstein equation with a cosmological constant

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Chinese Physics C 2024年第10期48卷 264-274页

作者： li-fang li Zhoujian Cao Xiaokai He Institute of mechanics Chinese Academy of SciencesBeijing 100190China Institute of Applied mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China School of mathematics and Statistics Hunan First Normal UniversityChangsha 410205China

Traditionally,the cosmological constant has been viewed as dark energy that mimics matter with negative *** that matter with negative energy provides a repulsive force,which fundamentally differs from typical gravitational forces,it has been believed that the cosmological constant effectively contributes a repulsive ***,it is important to note that the concept of gravitational force is valid only within the framework of Newtonian *** this study,we demonstrate that the traditional understanding of the gravitational force contributed by the cosmological constant is not entirely *** approach involves investigating the Newtonian limit of the Einstein equation with a cosmological *** subtleties involved in this analysis are discussed in ***,we find that the effect of the cosmological constant on Newtonian gravity is an attractive force rather than a repulsive one for ordinary *** expected,this corrective force is negligibly ***,our findings may offer a way to distinguish between dark energy and the cosmological constant,as one contributes a repulsive force while the other contributes an attractive force.

关键词： cosmological constant dark matter Einstein equation Newtonian limit dark energy

Carbon felt electrode coated with WS2 enables a high-performance polysulfide/ferricyanide flow battery

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Rare Metals 2024年第10期43卷 5039-5047页

作者： liang-Yu li Su Yan Ying-Jia Huang fang-fang Zhong Jin-Chao Cao Mei Ding Chuan-Kun Jia College of Materials Science and Engineering Changsha University of Science and Technology Institute of Energy Storage Technology College of Energy and Power EngineeringChangsha University of Science and Technology Binzhou Institute of Technology Weiqiao-UCAS Science and Technology Park

Polysulfide/ferricyanide flow batteries （S/Fe RFBs）,with the advantages of abundant earth reservation low cost,high safety,and environmental friendliness,have attracted significant interest and demonstrated noteworthy potential for practical ***,the battery performance,including the energy efficiency （EE）,voltage efficiency （VE）,and power density of the S/Fe RFBs remains low owing to the slow redox kinetics of polysulfide *** address these concerns,WS2was selected as the booster and deposited on a commercial carbon felt electrode （WS2–CF） to stimulate the redox reactions of polysulfide *** better hydrophilicity and smaller charge-transfer resistance,WS2–CF exhibits enhanced electrochemical activity toward polysulfide redox ***,the battery performance of S/Fe RFB with WS2–CF as the anode has been improved,with EE of 84%,VE of 84%,and a peak power density of 175.7 mW·cm-2,which are all higher than the cell only with the bare carbon felt （CF） as electrodes (76%,77% and 155.8 mW·cm-2,respectively).Furthermore,the cycling life of the S/Fe RFB with WS2–CF has been prolonged to 2200 cycles with a capacity retention of 96% a 40 mA·cm-2because of the good stability of WS2–CF as the ***,under the same conditions,the S/Fe RFB without WS2–CF terminated after 1500 cycles with a fast capacity *** successful utilization of WS2as a booster on an electrode provides an efficient strategy for obtaining advanced S/Fe RFBs for practical applications.

关键词： Carbon felt Energy storage Polysulfide/ferricyanide flow battery Tungsten disulfide

Local field potentials,spiking activity,and receptive fields in human visual cortex

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Science china(life Sciences) 2024年第3期67卷 543-554页

作者： Lu Luo Xiongfei Wang Junshi Lu Guanpeng Chen Guoming Luan Wu li Qian Wang fang fang School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health Peking UniversityBeijing 100871China School of Psychology Beijing Sport UniversityBeijing 100084China department of Neurosurgery Sanbo Brain HospitalCapital Medical UniversityBeijing 100093China Beijing Key Laboratory of Epilepsy Epilepsy CenterSanbo Brain HospitalCapital Medical UniversityBeijing 100093China IDG/McGovern Institute for Brain Research Peking UniversityBeijing 100871China Peking-Tsinghua Center for life Sciences Peking UniversityBeijing 100871China Beijing Institute for Brain Disorders Beijing 100069China State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research Beijing Normal UniversityBeijing 100875China

The concept of receptive field(RF) is central to sensory neuroscience. Neuronal RF properties have been substantially studied in animals,while those in humans remain nearly unexplored. Here, we measured neuronal RFs with intracranial local field potentials(LFPs) and spiking activity in human visual cortex(V1/V2/V3). We recorded LFPs via macro-contacts and discovered that RF sizes estimated from lowfrequency activity(LFA, 0.5–30 Hz) were larger than those estimated from low-gamma activity(LGA, 30–60 Hz) and high-gamma activity(HGA, 60–150 Hz). We then took a rare opportunity to record LFPs and spiking activity via microwires in V1 simultaneously. We found that RF sizes and temporal profiles measured from LGA and HGA closely matched those from spiking activity. In sum, this study reveals that spiking activity of neurons in human visual cortex could be well approximated by LGA and HGA in RF estimation and temporal profile measurement, implying the pivotal functions of LGA and HGA in early visual information processing.

关键词： human visual cortex receptive field intracranial EEG local field potential spiking activity