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Mg/MgO interfaces as efficient hydrogen evolution cathodes causing accelerated corrosion of additive manufactured Mg alloys:A DFT analysis

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Journal of Magnesium and Alloys 2024年第1期12卷 110-119页

作者： Man-Fai ng Kai xiang Kuah Teck Leong Tan Daniel John Blackwood Department of Materials Science&Engineering National University of Singapore9 Engineering Drive 1Singapore 117575Republic of Singapore Institute of High Performance Computing(IHPC) Agency for ScienceTechnology and Research(A∗STAR)1 Fusionopolis Way#16-16 ConnexisSingapore 138632Republic of Singapore

The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide *** Kelvin Probe Force Microscopy demonstrated that MgO inclusions could act as cathodes for Mg corrosion,but their low conductivity likely precludes ***,the density of state calculations through density functional theory using hybrid HSE06 functional revealed overlapping electronic states at the Mg/MgO interface,which facilitates electron transfers and participates in redox *** determination of the hydrogen absorption energy at the Mg/MgO interface reveals it to be an excellent catalytic site,with HER being found to be a factor of 23x more efficient at the interface than on metallic *** results not only support the plausibility of the Mg/MgO interface being an effective cathode to the adjacent anodic Mg matrix during corrosion but also contribute to the understanding of the enhanced cathodic activities observed during the anodic dissolution of magnesium.

关键词： Magnesium Magnesium oxide Interface Hydrogen evolution DFT

Effectiveness of mindfulness-based interventions on the well-being of healthcare workers:a systematic review and meta-analysis

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General Psychiatry 2024年第3期37卷 335-344页

作者： Natasha Yixuan Ong Finn Jing Jie Teo Jane Zi Ying Ee Chun En Yau Julian Thumboo Hiang Khoon Tan Qin xiang ng NUS Yong Loo Lin School of Medicine National University of SingaporeSingapore Health Services Research Unit Singapore General HospitalSingapore SingHealth Duke-NUS Medicine Academic Clinical Programme Duke-NUS Medical SchoolSingapore Singhealth Duke-NUS Global Health Institute Singapore Duke Global Health Institute Duke UniversityDurhamNorth CarolinaUSA Division of Surgery and Surgical Oncology Singapore General HospitalSingapore Saw Swee Hock School of Public Health National University of Singapore and National University Health SystemSingapore

Background Grow.ng evidence attests to the efficacy of mindfulness-based interventions(MBIs),but their effectiveness for healthcare workers remains *** To evaluate the evidence for MBIs in improving healthcare workers’psychological *** A systematic literature search was conducted on Medline,Embase,Cumulative Index for Nursing and Allied Health Literature,PsycINFO and Cochrane Central Register of Controlled Trials up to 31 August 2022 using the keywords‘healthcare worker’,‘doctor’,‘nurse’,‘allied health’,‘mindfulness’,‘wellness’,‘workshop’and‘program’.Randomised controlled trials with a defined MBI focusing on healthcare workers and quantitative outcome measures related to subjective or psychological well-being were eligible for inclusion.R V.4.0.3 was used for data analysis,with the standardised mean difference as the primary outcome,employing DerSimonian and Laird’s random effects *** of Recommendations,Assessment,Development and Evaluation framework was used to evaluate the quality of ***’s Risk of Bias 2 tool was used to assess the risk of bias in the included *** A total of 27 studies with 2506 participants were included,mostly from the USA,involving various healthcare *** such as stress reduction programmes,apps,meditation and training showed small to large effects on anxiety,burnout,stress,depression,psychological distress and job strain outcomes of the *** effects were also seen in self-compassion,empathy,mindfulness and ***,long-term outcomes(1 month or longer postintervention)varied,and the effects were not consistently *** MBIs offer short-term benefits in reducing stress-related symptoms in healthcare *** review also highlights limitations such as intervention heterogeneity,reduced power in specific subgroup analyses and variable study quality.

关键词： nurse sustained workers

Multicolor circularly polarized phosphorescence of axially chiral binuclear platinum(Ⅱ) complexes

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Science China Chemistry 2024年第11期67卷 3757-3766页

作者： Jintong Song Rui Zeng Hui Xiao Hailiang Ni Zong-xiang Xu Haifeng xiang College of Chemistry and Materials Science Sichuan Normal University Department of Chemistry Southern University of Science and Technology College of Chemistry Sichuan University

D-A charge transfer, including through-bond charge transfer and through-space charge transfer between two different electron donors（D） and electron acceptors（A）, is a fundamental and powerful tool to tune the optical properties of organic dyes. Herein,we demonstrate a unique strategy to tune phosphorescence and circularly polarized luminescence properties of axially chiral binuclear Pt（Ⅱ） complexes through long-range charge transfer, even though these molecules have two totally identical segments on either side of the chiral core. The presence of axial chirality would break not only the symmetry of molecular structure and π-conjugation system but also the symmetry of charge distribution for long-range charge transfer. These binaphthyl-based Pt（Ⅱ）complexes bearing coordinated atoms far away from chiral axis exhibit no Pt-Pt interactions but colorful concentrationdependent phosphorescence with quantum yield up to 86.4% and could be applied as emitters in highly efficient solutionprocessed organic light-emitting diodes to achieve luminance, luminance efficiency, power efficiency, external quantum efficiency, and asymmetry factor up to 8.94 × 10～3cd m-2, 41.9 cd A-1, 18.8 lm w-1, 12.6% and 2.98 × 10-3, respectively. Therefore,the present work affords a new and simple way to utilize the inherently asymmetric advantage of chirality for the design of D-Abased organic dyes.

关键词： Pt(II) complexes organic light-emitting diodes circularly polarized phosphorescence axial chirality

Flexible electrochemical capacitor based NiMoSSe electrode material with superior cycling and structural stability

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Chinese Chemical Letters 2024年第7期35卷 456-460页

作者： Jingxuan Liu Shiqi Zhao xiang wu School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

Constructing composited electrode material is considered to be an efficient strategy to improve their electrochemical *** can accelerate the charge transfer speed of ions and enhance the conductivity of ***,the formation of the hybrid structure can largely avoid the aggregation of two dimensional materials and increase the electrochemical active area of the *** this work,we synthesize NiMoSSe electrode materials on nickel foam by a facile hydrothermal *** prepared composite shows a specific capacitance of 1035 C/g at 1 A/g due to the synergistic effect between MoS_(2) and MoSe_(2) *** addition,the devices are assembled with NiMoSSe samples,which offers an energy density of 82.71 wh/kg at a power density of 2700 w/kg.

关键词： Supercapacitors NiMoSSe Energy density Power density Cycling life

Elevated brain temperature under severe heat exposure impairs cortical motor activity and executive function

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Journal of Sport and Health Science 2024年第2期13卷 233-244页

作者： xiang Ren Tan Mary C.Stephenson Sharifah Badriyah Alhadad Kelvin w.Z.Loh Tuck wah Soong Jason K.w.Lee Ivan C.C.Low Health and Social Sciences Singapore Institute of TechnologySingapore 138683Singapore Human Potential Translational Research Programme Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117597Singapore Centre for Translational Magnetic Resonance Research Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117549Singapore Department of Physiology Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117593Singapore Heat Resilience and Performance Centre Yong Loo Lin School of MedicineNational University of SingaporeSingapore 117510Singapore N.1 Institute for Health National University of SingaporeSingapore 117456Singapore Campus for Research Excellence and Technological Enterprise(CREATE) Singapore 138602Singapore

Background:Excessive heat exposure can lead to hyperthermia in humans,which impairs physical performance and disrupts cognitive *** heat is a known physiological stressor,it is unclear how severe heat stress affects brain physiology and ***:Eleven healthy participants were subjected to heat stress from prolonged exercise or warm water immersion until their rectal temperatures(T_(re))attained 39.5℃,inducing exertional or passive hyperthermia,*** a separate trial,blended ice was ingested before and during exercise as a cooling *** were compared to a control condition with seated rest(normothermic).Brain temperature(T_(br)),cerebral perfusion,and task-based brain activity were assessed using magnetic resonance imaging ***:T_(br)in motor cortex was found to be tightly regulated at rest(37.3℃±0.4℃(mean±SD))despite fluctuations in T_(re).with the development of hyperthermia,T_(br)increases and dovetails with the rising T_(re).Bilateral motor cortical activity was suppressed during high-intensity plantarflexion tasks,implying a reduced central motor drive in hyperthermic participants(T_(re)=38.5℃±0.1℃).Global gray matter perfusion and regional perfusion in sensorimotor cortex were reduced with passive *** function was poorer under a passive hyperthermic state,and this could relate to compromised visual processing as indicated by the reduced activation of left lateral-occipital ***,ingestion of blended ice before and during exercise alleviated the rise in both T_(re)and T_(bc)and mitigated heat-related neural ***:Severe heat exposure elevates T_(br),disrupts motor cortical activity and executive function,and this can lead to impairment of physical and cognitive performance.

关键词： Brain functional activity Cognition Heat stress Hyperthermia Motor function

Persistent mixing bursts in the equatorial Pacific thermocline induced by persistent equatorial waves

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Journal of Oceanology and Limnology 2024年第2期42卷 492-510页

作者： Jingjing ZHAng Chuanyu LIU xiang GOng Fan w.ng School of Mathematics and Physics Qingdao University of Science and TechnologyQingdao 266100China Key Laboratory of Ocean Circulation and waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laoshan Laboratory Qingdao 266237China

A recent study by Liu et al.(2020)suggested that due to the saturation of equatorially trapped planetary waves with different dynamical types,temporal periods,meridional and baroclinic modes,complex layer structures of vertical velocity shear and hence turbulent mixing could frequently occur in the thermocline of the eastern equatorial *** investigated the occurrence of the interior turbulent mixing as indicated by shear instabilities,above the Equatorial Undercurrent(EUC)core at three equatorial sites along 140°w,170°w,and 165°E,respectively,based mainly on data from the Tropical Atmosphere and Ocean(TAO)mooring *** found that turbulent mixing bursts persisted in the thermocline of all three ***,the interior turbulent mixing layers(ITMLs)could occur in probability of approximately 68%,53%,and 48%at the three sites,*** overall occurrence probability shows obvious and similar biannual variations at 140°w and 170°w,which is higher in boreal from late summer to winter and lower in ***,the ITMLs are primarily located above the EUC core and prevail in deeper(shallower)layers from late summer to winter(spring).Most ITMLs(70%)lasted for hours to 3 days,and a few of them(15%)for more than 7 *** thicknesses of ITMLs were concentrated between 15 and 55 *** 165°E,the vertical distribution of ITML occurrence probability was different from that at 140°w and 170°w,as it did not show a preference for depths;the durations of ITMLs are short(also from hours to several days)and their thicknesses were between 5 and 25 *** properties,particularly the high occurrence probability,and short durations demonstrated the persistence of thermocline mixing in the western to eastern equatorial Pacific thermocline and confirmed the generation mechanism by persistent equatorial waves as well.

关键词： interior turbulent mixing layer(ITML) weakly sheared layer(wSL) Equatorial Undercurrent(EUC)core occurrence probability seasonality

Ultrasound-driven self-decomposition porphyrins as metal-free CO precursors for gas and sonodynamic synergistic therapy

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Science China Chemistry 2024年第5期67卷 1624-1635页

作者： Shuxin Liu Jinjuan Ma xiang Xu Aiguo w.ng Nan Zheng School of Chemical Engineering Dalian University of TechnologyDalian 116024China Department of Comparative Medicine Laboratory Animal Center Dalian Medical UniversityDalian 116000China Cancer Hospital of Dalian University of Technology Shenyang 116000China

Carbon monoxide(CO) is an endogenous therapeutic gas with an anti-tumor effect. The precise delivery and controlled release of CO in tumor tissues play crucial roles in anti-cancer treatment. However, efficient in situ generation of CO from metal-free COreleasing molecules(CORMs) remains a formidable challenge. Herein, we develop ultrasound(US)-driven self-decomposition porphyrin as organic and metal-free US-CORMs, which can spatiotemporally control the CO release(347 mmol CO/mol porphyrin) efficiently under physiologically harmless US conditions(1.0 MHz, 1.5 w/cm^(2), 50% duty cycle, 50 min). Moreover,porphyrin as a sonosensitizer can also generate reactive oxygen species(ROS) under US treatment to achieve sonodynamic therapy(SDT). Advanced functions of such porphyrin-based CORMs in CO gas-sonodynamic synergistic treatment have been demonstrated by evaluating the in vitro and in vivo anti-tumor effects.

关键词： porphyrin sonodynamic therapy metal-free CO precursors ultrasound-driven gas therapy

Exploring multiple phases and first-order phase transitions in Kármán Vortex Street

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 47-54页

作者： Xu Li Xing xiang Tingting Xue Limin w.ng Xiaosong Chen School of Systems Science and Institute of Nonequilibrium Systems Beijing Normal UniversityBeijing 100875China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy ofSciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Kármán Vortex Street, a fascinating phenomenon of fluid dynamics, has intrigued the scientific community for a long time. Many researchers have dedicated their efforts to unraveling the essence of this intriguing flow pattern. Here, we apply the lattice Boltzmann method with curved boundary conditions to simulate flows around a circular cylinder and study the emergence of Kármán Vortex Street using the eigen microstate approach, which can identify phase transition and its order-parameter. At low Reynolds number, there is only one dominant eigen microstate w_(1) of laminar flow. At Re_(c)^(1)= 53.6, there is a phase transition with the emergence of an eigen microstate pair w^(2,3) of pressure and velocity fields. Further at Re_(c)^(2)= 56, there is another phase transition with the emergence of two eigen microstate pairs w^(4,5) and w^(6,7). Using the renormalization group theory of eigen microstate,both phase transitions are determined to be first-order. The two-dimensional energy spectrum of eigen microstate for w^(1), w^(2,3) after Re_(c)^(1), w^(4-7) after Re_(c)^(2) exhibit-5/3 power-law behavior of Kolnogorov's K41 theory. These results reveal the complexity and provide an analysis of the Kármán Vortex Street from the perspective of phase transitions.

关键词： Kármán Vortex Street first-order phase transition eigen microstate approach renormalization group theory of eigen microstate

A high-entropy-designed cathode with V^(5+)-V^(2+) multi-redox for high energy density sodium-ion batteries

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Journal of Energy Chemistry 2024年第10期97卷 429-437,I0008页

作者： xiang Ding Xiaofen Yang Yibing Yang Liangwei Liu Yi Xiao Lili Han College of Chemistry and Materials Science Fujian Normal University.Fuzhou 350007FujianChina State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina

Na_(3)V_(2)(PO_(4))_(3)(NVP)is gifted with fast Na^(+)conductive NASICON *** it still suffers from low electronic conductivity and inadequate energy ***,a high-entropy modification strategy is realized by doping V^(3+)site with Ga^(3+)/Cr^(3+)/Al^(3+)/Fe^(3+)/In^(3+)simultaneously(***_(3)V_(2-x)(GaCrAlFeIn)_x(PO_(4))_(3);x=0,0.04,0.06,and 0.08)to stimulate the V^(5+)■V^(2+)reversible multi-electron *** configuration high-entropy can effectively suppress the structural collapse,enhance the redox reversibility in high working voltage(4.0 V),and optimize the electronic induced *** in-situ X-ray powder diffraction and in-situ electrochemical impedance spectroscopy tests efficaciously confirm the robust structu ral recovery and far lower polarization throughout an entire charge-discharge cycle during 1.6-4.3 V,***,the density functional theory calculations clarify the stronger metallicity of high-entropy electrode than the bare that is derived from the more mobile free electrons surrounding the vicinity of Fermi *** grace of high-entropy design and multi-electron transfer reactions,the optimal Na_(3)V_(1.7)(GaCrAlFeIn)_(0.06)(PO_(4))_(3)can exhibit perfect cycling/rate performances(90.97%@5000 cycles@30 C;112 mA h g^(-1)@10 C and 109 mA h g^(-1)@30 C,2.0-4.3 V).Furthermore,it can supply ultra-high185 mA h g^(-1)capacity with fa ntastic energy density(522 w h kg^(-1))in half-cells(1.4-4.3 V),and competitive capacity(121 mA h g^(-1))as well as energy density(402 w h kg^(-1))in full-cells(1.6-4.1 V),demonstrating enormous application potential for sodium-ion batteries.

关键词： Na_(3)V_(2)(PO_(4))_(3) High-entropy V^(5+)■V^(2+)multi-redox High energy density Sodium-ion batteries