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Recent progress in carbene-catalyzed fluoroalkylation

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Science China Chemistry 2024年第8期67卷 2448-2460页

作者： bei Zhang Xuan Zhang Jian wang Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science and TechnologyNanjing 210044China School of Pharmaceutical Sciences Tsinghua UniversityBeijing 100084China

The fluoroalkyl fragment plays a vital role in various fields such as pharmaceuticals and materials science, and has a significant impact on human life not only on the present but also in the future. The insertion of fluoroalkyl groups into the chemical skeletons can cause considerable alternations in the chemical, physical and biological properties of molecules, which has attracted numerous scientists from different fields. This review focuses on N-heterocyclic carbene(NHC)-catalyzed fluoroalkylation reactions, providing a detailed analysis and summary of the achievements in the past two decades. Many successful examples clearly indicate that NHCs can catalyze the tranformation of fluoroalkylation reagents with various electronic characteristics, whether electrophilic, nucleophilic, or radical precursors. Herein, the fluoroalkylation reactions are classified based on different catalytic modes of NHCs: Lewis base catalysis, Umploung catalysis, radical catalysis and others. Meanwhile, by refining and systematically studying the contribution of NHC catalysis in fluoroalkylation reactions, this review is expected to provide valuable insights and enlightenment for related fields.

关键词： N-heterocyclic carbene fluoroalkylation radical catalysis

Function-reversible facets enabling SrTiO_(3)nanocrystals for improved photocatalytic hydrogen evolution

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Frontiers in Energy 2024年第1期18卷 101-109页

作者： Bin wang bei AN Xiaoqian LI Shaohua SHEN School of Physics Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter(Ministry of Education)Key Laboratory of Shaanxi for Advanced Materials and Mesoscopic PhysicsXi’an Jiaotong UniversityXi’an 710049China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

It has been widely reported that,for faceted nanocrystals,the two adjacent facets with different band levels contribute to promoted charge separation,and provide active sites for photocatalytic reduction and oxidation reaction,*** such cases,only one family of facets can be used for photocatalytic hydrogen ***,by using SrTiO_(3)nanocrystals enclosed by{023}and{001}facets as a model photocatalyst,this paper proposed a strategy to achieve the full-facets-utilization of the nanocrystals for photocatalytic hydrogen via chemically depositing Pt nanoparticles on all *** photo-deposition experiment of CdS provided direct evidence to demonstrate that the{023}facets which were responsible for photooxidation reaction can be function-reversed for photocatalytic hydrogen evolution after depositing Pt nanoparticles,together with the{001}***,the full-facets-utilization led to a much-improved activity for photocatalytic hydrogen,in contrast to those SrTiO_(3)nanocrystals with only{001}facets deposited by Pt nanoparticles via a photo-deposition method.

关键词： SrTiO_(3)nanocrystals crystal facets photocatalysis hydrogen evolution

Ethanol extract of Abelmoschus manihot suppresses endoplasmic reticulum stress in contrast-induced nephropathy

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Asian Pacific Journal of Tropical Biomedicine 2024年第1期14卷 17-27,I0002,I0003页

作者： Xin Lin Xin Lu yun-He Zhao Yi-bei wang Ru-Ge Niu Xiao-Hu Chen Department of Cardiology Affiliated Hospital of Nanjing University of Chinese MedicineJiangsu Province Hospital of Chinese MedicineNanjingJiangsu 210004China

Objective:To explore the efficacy and potential mechanisms of the ethanol extract of Abelmoschus manihot(L.)Medic in contrast-induced nephropathy(CIN).Methods:CIN rat models and human renal proximal tubular cells(HK-2)with iopromide-induced injury were employed to mimic CIN *** effect of Abelmoschus manihot extract on the rat models and HK-2 cells was *** rat models,kidney function,histology,oxidative stress and apoptosis were *** HK-2 cells,cell viability,apoptosis,mitochondrial membrane potential,and endoplasmic reticulum stress were ***:Abelmoschus manihot extract significantly improved structural and functional impairments in the kidneys of CIN ***,the extract effectively mitigated the decline in cellular viability and reduced iopromide-induced oxidative stress and lipid *** investigations revealed that Abelmoschus manihot extract prominently attenuated acute endoplasmic reticulum stress-mediated apoptosis by downregulating GRP78 and CHOP protein ***:Abelmoschus manihot extract can be used as a promising therapeutic and preventive agent in the treatment of CIN.

关键词： Contrast-induced nephropathy Abelmoschus manihot extract ER stress Apoptosis GRP78 CHOP

Coupling ideality of standing-wave supermode microresonators

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Photonics Research 2024年第8期12卷 1610-1618页

作者： MIN wang YUECHEN LEI ZHI-GANG HU CHENGHAO LAO YUANLEI wang XIN ZHOU JINCHENG LI QI-FAN YANG bei-bei LI beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China School of Physics Beihang UniversityBeijing 100191China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Songshan Lake Materials Laboratory Dongguan 523808China

Standing-wave supermode microresonators that are created through the strong coupling between counter-propagating modes have emerged as versatile platforms for sensing and nonlinear *** example,these microresonators have shown potential in nanoparticle sizing and counting,as well as enhancing the single-photon optomechanical coupling rate of stimulated Brillouin ***,it has been observed that the relation between the mode linewidth and on-resonance transmission of the split supermodes differs obviously from that of the non-split *** behavior is typically quantified by the coupling ideality(I),which remains inadequately explored for the standing-wave *** this study,we theoretically and experimentally investigate the coupling ideality of standing-wave supermodes in a commonly employed configuration involving a Si O2microresonator side-coupled to a tapered *** findings demonstrate that,even with a single-mode tapered fiber,the coupling ideality of the standing-wave supermodes is limited to 0.5,due to the strong backscattering-induced energy loss into the counter-propagating direction,resulting in an additional equivalent parasitic *** achieving a coupling ideality of 0.5 presents challenges for reaching over-coupled regimes,it offers a convenient approach for adjusting the total linewidth of the modes while maintaining critically-coupled conditions.

关键词： ideality mode wave

Hyperinsulinemia,Insulin Resistance and Cognitive Decline in Older Cohort

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Biomedical and Environmental Sciences 2012年第1期25卷 8-14页

作者： ZHONG Yuan MIAO Ya JIA Wei Ping YAN Hong wang bei yun JIN Jun Department of Geriatrics Sixth People＇s Hospital Affiliated to Shanghai Jiao Tong University Shanghai 200233 China Department of Endocrinology and Metabolism Sixth People＇s Hospital Affiliated to Shanghai Jiao Tong University Shanghai Diabetes Institute Shanghai 200233 China

Objective decline of resistance whether H Type 2 diabetes has been recently recognized as an important risk factor for cognitive patients with Alzheimer＇s disease （AD）. But the roles of hyperinsulinemia （HI） and insulin （IR） in the development of AD are still controversial. This study was designed to evaluate or IR influenced the cognitive functions of older cohort. Methods The cognitive functions of 328 consecutive elderly patients were evaluated with a battery of cognitive rating scales. Their fasting blood glucose （FBG） and fasting insulin （FINS） were analyzed and IR was calculated with modified-Homa. The cognitive scores in different groups and the correlation of cognitive functions with HI or IR were analyzed. Results In our study, there were 180 participants with HI and 148 without HI, and 192 with iR and 136 without IR. The participants with HI showed worse cognitive functions than those without HI in MMSE, MOCA, CDR, orientation, delayed memory, and attention/calculation domains. Similarly, the elderly with IR had lower cognitive scores than those without IR in MMSE, MOCA, CDR, GDS, orientation, delayed memory, and attention/calculation domains. The insulin levels and Homa IR had negative correlation with the scores of MMSE and delayed memory, not only in the model I adjusted for FBG and diabetes history, but also in the model 2 adjusted for all nine demographic characteristics. Conclusion HI and IR are important risk factors for cognitive decline of the elderly, especially for the dysfunctions in delayed memory domains.

关键词： Cognitive function Alzheimer's disease Hyperinsulinemia Insulin resistance

Risk Factors Asscociated with Hypokalemia during Postanesthesia Recovery and Its Impact on Outcomes in Gynecological Patients:A Propensity Score Matching Study

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Current Medical Science 2024年第2期44卷 441-449页

作者： bei-bei wang Li HU Xin-yue HU Dong HAN Jing WU Department of Anesthesiology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China Institute of Anesthesia and Critical Care Medicine Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China Key Laboratory of Anesthesiology and Resuscitation(Huazhong University of Science and Technology) Ministry of EducationWuhan430022China

Objective:This study aimed to explore the risk factors and outcomes of hypokalemia during the recovery period from anesthesia in the gynecological ***:This retrospective cohort study included 208 patients who underwent gynecological surgery at our institution between January 2021 and March *** were collected for each patient,including demographics,disease status,surgical data,and clinical *** bowel preparation,postoperative gastrointestinal function,and electrolyte levels were compared between the two groups using propensity score matching(PSM).Results:The incidence of hypokalemia(serum potassium level<3.5 mmol/L)during the recovery period from anesthesia was approximately 43.75%.After PSM,oral laxative use(96.4%vs.82.4%,P=0.005),the number of general enemas(P=0.014),and the rate of≥2 general enemas(92.9%vs.77.8%,P=0.004)were identified as risk factors for hypokalemia,which was accompanied by decreased PaCO_(2) and *** were no significant differences in postoperative gastrointestinal outcomes,such as the time to first flatus or feces,the I-FEED score(a scoring system was created to evaluate impaired postoperative gastrointestinal function),or postoperative recovery outcomes,between the hypokalemia group and the normal serum potassium ***:Hypokalemia during postanesthesia recovery period occurred in 43.75%of gynecological patients,which resulted from preoperative mechanical bowel preparation;however,it did not directly affect clinical outcomes,including postoperative gastrointestinal function,postoperative complications,and length of hospital stay.

关键词： hypokalemia gynecological surgery postanesthesia recovery perioperative electrolyte disturbances postoperative recovery

Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition

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Acta Geochimica 2024年第4期43卷 661-676页

作者： Jie wang yun Liu Research Center for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China CAS Center for Excellence in Comparative Planetology Hefei 230026China

Isotope eff ects are pivotal in understanding silicate melt evaporation and planetary accretion *** on the Hertz-Knudsen equation,the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified ***,we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the *** propose a new model designed for silicate melt evaporation under *** model considers multiple steps including mass transfer,chemical reaction,and *** derivations reveal a kinetic isotopic fractionation factor(KIFF orα)αour model=[m(^(1)species)/m(^(2)species)]^(0.5),where m(species)is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes,*** model can eff ectively reproduce most reported KIFFs of laboratory experiments for various elements,i.e.,Mg,Si,K,Rb,Fe,Ca,and ***,the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the eff ects of low P_(H2)pressure,composition,and *** addition,we find that chemical reactions,diffusion,and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(−ln f)versus ln(t).Notably,our model allows for the theoretical calculations of parameters like activation energy(E_(a)),providing a novel approach to studying compositional and environmental eff ects on evaporation processes,and shedding light on the formation and evolution of the proto-solar and Earth-Moon systems.

关键词： Evaporation Kinetic isotopic fractionation Chemical kinetics Hertz-Knudsen equation CAIS

An electromagnetic semi-active dynamic vibration absorber for thin-walled workpiece vibration suppression in mirror milling

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Applied Mathematics and Mechanics(English Edition) 2024年第8期45卷 1315-1334页

作者： Jianghua KONG bei DING Wei wang Zhixia wang Juliang XIAO Hongyun QIU School of Mechanical Engineering Tianjin UniversityTianjin 300350China Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin 300350China Key Laboratory of Modern Mechanisms and Equipment Design of the State Ministry of Education Tianjin UniversityTianjin 300350China

As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local *** address these challenges,we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA),which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror *** system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling ***,the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator,which alters the distance between *** resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool *** frequency shift characteristics and vibration absorption performance are comprehensively *** and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool,resulting in a vibration suppression rate of approximately 47.57%.Moreover,the roughness of the machined surface decreases by18.95%,significantly enhancing the surface *** results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.

关键词： semi-active dynamic vibration absorber(SADVA) mirror milling selfsensing vibration absorption tuning thin-walled workpiece

Efficient overall photosynthesis of H_(2)O_(2) by the BTz@Mn_(0.2)Cd_(0.8)S S-scheme heterojunction

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Science China Chemistry 2024年第6期67卷 1953-1960页

作者： Zhongyue Chen Sijie Wan bei Cheng wang wang Yao Xiang Jiaguo Yu Shaowen Cao State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China Hubei Technology Innovation Center for Advanced Composites Wuhan University of TechnologyWuhan430070China Hospital of Wuhan University of Technology Wuhan University of TechnologyWuhan430070China Laboratory of Solar Fuel Faculty of Materials Science and ChemistryChina University of GeosciencesWuhan430074China

The photosynthesis of hydrogen peroxide(H_(2)O_(2))through the selective 2e^(-)oxygen reduction reaction(ORR)from O_(2)and H_(2)O stands out as an environmentally sustainable and cost-effective method for generating this essential ***,the widespread application of most photocatalysts is impeded by their reliance on sacrificial *** this context,we present a noteworthy advancement in the form of a step-scheme(S-scheme)heterojunction involving a donor-acceptor(D-A)-conjugated polymer and manganese cadmium sulfide(BTz@MCS).This innovative configuration enables efficient photocatalytic H_(2)O_(2)production within a non-sacrificial system,showcasing an impressive H_(2)O_(2)yield of 5,368μmol g^(-1)h^(-1)and an apparent quantum yield of 4.5%at 420 *** insights gained from in-situ irradiated X-ray photoelectron spectroscopy(ISIXPS),in-situ diffuse reflectance infrared Fourier transformations spectroscopy(DRIFTS),and density function calculations(DFT),it is revealed that the sp^(2)C between thiazole-thiazole rings at the BTz and the concentrated holes at the MCS function as spatially separated redox *** centers catalyze the selective 2e^(-)ORR and 4e^(-)water oxidation reaction(WOR)*** O_(2)generated from the WOR is subsequently utilized by the ORR cycle,enabling the overall photosynthesis of H_(2)O_(2)with accelerated total reaction ***,the high photocatalytic performance of the developed catalyst is attributed to well-designed S-scheme heterojunctions with tuned band *** spatially separated redox centers and effective transfer of photogenerated charge carriers facilitated by the internal electric field significantly enhance reaction *** study introduces a promising avenue for photocatalytic H_(2)O_(2)production without sacrificial agents,providing valuable insights into the underlying mechanisms in S-scheme heterojunctions.

关键词： hydrogen peroxide non-sacrificial redox centers S-scheme heterojunction