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Tensile deformation of fine-grained Mg at 4K,78K and 298K

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Journal of Magnesium and Alloys 2024年第6期12卷 2534-2556页

作者： M.Walag A.Kula P.Noga T.Tokarski g.Cios M.Niewczas AgH University of Krakow Faculty of Non-Ferrous MetalsKrakowPoland AgH University of Krakow Academic Centre for Materials and NanotechnologyKrakowPoland Materials Science and Engineering McMaster UniversityHamiltonCanada

The impact of grain size, ranging from 0.9 μm to 9 μm, on the mechanical properties of commercially pure Mg is investigated at temperatures of 4K, 78K, and 298K. The mechanisms governing plastic flow are influenced by both grain size and temperature. At 4K and 78K, dominant deformation modes in Mg involve dislocation glide and extension twinning, regardless of grain size. The interactions between basal and non-basal dislocations and dislocations with grain boundaries promote an unusually high rate of work hardening in the plastic regime, leading to premature failure. The yield stress follows the Hall-Petch relationship σy~ k/√d, with the slope k increasing with decreasing temperature. At 298K, in addition to dislocation glide and twinning, grain boundary sliding(gBS) becomes significant in samples with grain sizes below 3 μm, considerably enhancing the material's deformability. gBS activation provides an additional recovery mechanism for dislocations accumulating at grain boundaries, facilitating their absorption during sliding and rotation. Analysis of σ Θ relationship suggests that the basal slip is the dominant dislocation mode in Mg at 298K. Decreasing grain size suppresses dislocation activity and twinning and increases gBS, resulting in lower Θ and σ Θ values. Suppressing conventional deformation modes coupled with enhanced gBS yields stress softening, breaking down the Hall-Petch relationship in Mg below 3 μm grain size, leading to an inverse Hall-Petch behaviour. The work reports new data on the strength, ductility, work hardening and fracture behaviour, and their variations with Mg grain size across different temperature regimes.

关键词： Polycrystalline Mg Mechanical properties Deformation mechanisms Work-hardening Texture evolution Cryogenic temperatures Hall-Petch relationship

The initial stages of Li_(2)O_(2) formation during oxygen reduction reaction in Li-O_(2) batteries:The significance of Li_(2)O_(2) in charge-transfer reactions within devices

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Journal of Energy Chemistry 2024年第1期88卷 223-231,I0006页

作者： Daniela M.Josepetti Bianca P.Sousa Simone A.J.Rodrigues Renato g.Freitas gustavo Doubek Advanced Energy Storage Division LABCenter for Innovation on New EnergiesSchool of Chemical EngineeringUniversity of CampinasAv Albert Einstein 50013083-852CampinasSPBrazil Institute of Physics&Department of Chemistry Laboratory of Computational MaterialsFederal University of Mato Grosso78060-900CuiabáMTBrazil

Lithium-oxygen batteries are a promising technology because they can greatly surpass the energy density of lithium-ion ***,this theoretical characteristic has not yet been converted into a real device with high *** with air contamination,metallic lithium reactivity,and complex discharge and charge reactions are the main issues for this technology.A fast and reversible oxygen reduction reaction(ORR)is crucial for good performance of secondary batteries',but the partial knowledge of its mechanisms,especially when devices are concerned,hinders further *** this perspective,the present work uses operando Raman experiments and electrochemical impedance spectroscopy(EIS)to assess the first stages of the discharge processes in porous carbon electrodes,following their changes cycle by cycle at initial operation.A growth kinetic formation of the discharge product signal(Li_(2)O_(2))was observed with operando Raman,indicating a first-order reaction and enabling an analysis by a microkinetic *** solution mechanism in the evaluated system was ascribed for an equivalent circuit with three time *** the time constant for the anode interface reveals to remain relatively constant after the first discharge,its surface seemed to be more *** model indicated that the reaction occurs at the Li_(2)O_(2) surface,decreasing the associated resistance during the initial discharge ***,the growth of Li_(2)O_(2) forms a hetero-phase between Li_(2)O_(2)/electrolyte,while creating a more compact and homogeneous on the Li_(2)O_(2)/cathode *** methodology here described thus offers a way of directly probing changes in surface chemistry evolution during cycling from a device through EIS analysis.

关键词： Li-O_(2)battery Operando Raman analysis Equivalent circuit modeling Time-constant distribution

Achieving superior performance in powder-metallurgy near-βtitanium alloy by combining hot rolling and rapid heat treatment followed by aging

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Journal of Materials Science & Technology 2024年第4期171卷 24-36页

作者： Fucheng Qiu Tuo Cheng Yuchao Song Orest M.Ivasishin Dmytro g.Savvakin guangyu Ma Huiyan Xu College of Materials Science and Engineering Jilin UniversityChangchun 130025China International Center of Future Science Jilin UniversityChangchun 130025China g.V.Kurdyumov Institute for Metal Physics KyivUkraine College of Biological and Agricultural Jilin UniversityChangchun 130025China

Heat treatment plays an important role in tailoring the mechanical properties of powder-metallurgy(PM)titanium ***,only limited work about the rapid heat treatment(RHT)of PM titanium alloys has been *** this work,RHT was applied to PM Ti-5Al-5Mo-5V-1Cr-1Fe alloy after hot rolling to study the evolution of its mechanical properties and the influence of residual pores on its *** hot rolling and annealing,a fine and uniformα+βstructure with few residual pores is *** RHT,the primaryαdissolves gradually and completes in theβregion,and theβgrains then grow,resulting in the continuous decrease in elongation after ***,the tensile strength first increases and then decreases with increasing RHT temperature,owing to the increase in volume fraction of secondaryαinα+βregion and theβgrain growth inβ*** contrast to the RHT of cast-and-wrought titanium,the negative influence of residual pores lowers the RHT temperature for obtaining the highest tensile strength to a temperature below theβ-transus *** the negative influence of the residual pores,retained primaryαand fineβgrains with fine secondaryαinside contribute to achieving a good strength/ductility balance(1570 MPa and 6.1%,respectively).Addi-tionally,although at higher cycles to failure,the negative influence of residual pores increases as it affects the crack initiation zone at the subsurface,the good resistance of secondaryαto fatigue crack propaga-tion still enhances the fatigue strength considerably(about 300 MPa).This work suggests a cost-effective strategy to produce titanium alloys with high performance.

关键词： Rapid heat treatment Powder metallurgy Mechanical properties Near-βtitanium Residual pores

Thermodynamic analysis of metal segregation in dual phase high entropy ceramics

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Journal of Materiomics 2024年第4期10卷 889-895页

作者： Steven M.Smith II William g.Fahrenholtz gregory E.Hilmas Stefano Curtarolo Missouri University of Science and Technology Materials Science and Engineering DepartmentRollaMO65409USA Duke University Department of Mechanical Engineering and Materials ScienceDurhamNC27708USA Duke University Center of Autonomous Materials DesignDurhamNC27708USA

Equilibrium gibbs'free energy calculations were used to determine metal segregation trends between boride and carbide solid solutions containing two metals that are relevant to dual phase high entropy *** model predicted that Ti had the strongest tendency to segregate to the boride phase followed by Zr,Nb,Mo,V,Hf,and Ta,which matches experimental results of measured *** ratio of a metal in the carbide phase to the content of the same metal in the corresponding metal boride had a linear trend with the change in standard gibbs'free energy of reaction for a metal carbide reacting with B_(4)C to produce its corresponding metal boride and *** proposed model was used to predict the changes in standard gibbs'free energy for CrC→CrB_(2) to be−260 kJ and WC→WB_(2) to be 148 kJ,which indicates that Cr has the strongest segregation to the boride and W has the strongest segregation to the *** proposed model can be used to estimate the segregation of metals in dual phase high entropy boride-carbide ceramics of any boride/carbide ratio or metal content.

关键词： Dual phase High entropy ceramic Boride Carbide Thermodynamics

Pollen analysis reveals the effects of uncovered interactions,pollen-carrying structures,and pollinator sex on the structure of wild bee-plant networks

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Insect Science 2024年第3期31卷 971-988页

作者： Clément Tourbez Carmelo gómez-Martínez MiguelÁngel gonzalez-Estévez Amparo Lazaro Mediterranean Institute for Advanced Studies(UIB-CSIC) Global Change Research GroupEsporlesBalearic IslandsSpain Department of Biology Ecology AreaUniversity of the Balearic/slandsPalmaSpain

Pollination networks are increasingly used to model the complexity of interactions between pollinators and flowering plants in *** methods exist to sample these interactions,with direct observations of plant-pollinator contacts in the field being by far the most *** the identification of pollen carried by pollinators allows uncovering interactions and increasing sample sizes,the methods used to build pollen-transport networks are variable and their effect on network structure remains *** understand how interaction sampling influences the structure of networks,we analyzed the pollen found on wild bees from eight communities across Mallorca Island and investigated the differences in pollen loads between bee body parts(scopa ***)and *** then assessed how these differences,as well as the uncovered interactions not detected in the field,influenced the structure of wild bee-plant *** identified a higher quantity and diversity of pollen in the scopa than in the rest of the female body,but these differences did not lead to differences in structure between plant-pollination(excluding scopa pollen)and bee-feeding interaction(including scopa pollen)***,networks built with pollen data were richer in plant species and interactions and showed lower modularity and specialization(H2'),and higher nestedness than visitation networks based on field *** interactions with plants were stronger compared to those of males,although not ***,females were more generalist(low d')and tended to be more central in interaction networks,indicating their more key role structuring pollination networks in comparison to *** study highlights the importance of palynological data to increase the resolution of networks,as well as to understand important ecological questions such as the differences between plant-pollination and bee-feeding interaction networks,and the role of sexes in pollination.

关键词： palynology pollen-transport networks pollination role of bee sexes sampling methodology visitation networks

The storage and utilization of carbohydrates in response to elevation mediated by tree organs in subtropical evergreen broad-leaved forests

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Forest Ecosystems 2024年第1期11卷 52-61页

作者： Bin Xu Xueli Jiang Yingying Zong g.geoff Wang Fusheng Chen Zhenyu Zhao Xiangmin Fang Key Laboratory of National Forestry and grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of ForestryJiangxi Agricultural UniversityNanchang330045China Jiulianshan National Observation and Research Station of Chinese Forest Ecosystem College of ForestryJiangxi Agricultural UniversityNanchang330045China Department of Forestry and Environmental Conservation Clemson UniversityClemsonSC29634USA

global climate change can affect tree growth and carbon sink function by influencing plant carbohydrate synthesis and utilization,while elevation can be used as an ideal setting under natural conditions to simulate climate change *** effect of elevation on tree growth may depend on organ ***,the allocation patterns of nonstructural and structural carbohydrates(NSCs and SCs,respectively)in different tree organs and their response to elevation remain *** selected four dominant tree species,Schima superba,Castanopsis eyrei,Castanopsis fargesii and Michelia maudiae,along an elevation gradient from 609 to 1,207 m in subtropical evergreen broad-leaved forests and analyzed leaf,trunk,and fine root NSCs,carbon(C),nitrogen(N)and phosphorus(P)concentrations and the relative abundance of *** NSCs increased initially and then decreased,and trunk NSCs increased with increasing ***,root NSCs decreased with increasing *** relative abundance of SCs in leaves and trunks decreased,while the relative abundance of root SCs increased with increasing *** significant correlations between SCs and NSCs in leaves were detected,while there were negative correlations between SCs and NSCs in trunks,roots,and all *** partitioning analysis indicated that plant C/N and C/P were the main predictors of changes in SCs and *** results suggest that tree organs have divergent responses to elevation and that increasing elevation will inhibit the aboveground part growth and enhance the root growth of trees.A tradeoff between the C distribution used for growth and storage was confirmed along the elevation gradient,which is mainly manifested in the"sink"organs of *** results provide insight into tree growth in the context of global climate change scenarios in subtropical forest ecosystems.

关键词： Nonstructural carbohydrates Structural carbohydrates Elevation Subtropical evergreen broad-leaved forests Tree organs

A randomized,controlled,open label non-inferiority trial of intravenous ferric carboxymaltose versus iron sucrose in patients with iron deficiency anemia in China

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Frontiers of Medicine 2024年第1期18卷 98-108页

作者： Jie Jin Zhihua Ran Emanuele Noseda Bernard Roubert Matthieu Marty Anna Mezzacasa Udo Michael göring The First Affiliated Hospital Zhejiang University College of MedicineHangzhou310058China Renji Hospital Shanghai Jiao Tong University School of MedicineShanghai200025China Vifor Pharma Glattbrugg8152Switzerland

Iron deficiency(ID)and ID anemia(IDA)pose significant public health concerns in *** iron sucrose(IS)treatment is well-established in the country,ferric carboxymaltose(FCM)offers the advantage of higher doses and fewer *** open label,randomized,controlled,non-inferiority trial was conducted at multiple sites in China to compare the outcomes of FCM(maximum of 2 doses,500 or 1000 mg iron)and IS(up to 11 infusions,200 mg iron)treatments in subjects with *** primary endpoint was the achievement of hemoglobin(Hb)response(an increase of⩾2 g/dL from baseline)within 8 weeks,whereas secondary endpoints included changes in Hb,transferrin saturation,and serum ferritin *** the 371 randomized subjects,a similar percentage of subjects treated with FCM and IS achieved Hb-response(FCM 99.4%,IS 98.3%),thereby confirming the non-inferiority of FCM compared with IS(difference 1.12(−2.15,4.71;95%confidence interval(CI))).Furthermore,a significantly higher proportion of FCM-treated subjects achieved early Hb-response at Week 2(FCM 85.2%,IS 73.2%;difference 12.1(3.31,20.65;95%CI)).Additionally,the increase in TSAT and serum ferritin levels from baseline was significantly greater at all time points for FCM-treated *** safety profiles of FCM and IS were comparable,with the exception of transient hypophosphatemia and pyrexia,which are consistent with FCM’s known safety *** conclusion,FCM proves to be an efficacious treatment for IDA,providing faster Hb-response and correction of ID with fewer administrations than IS.

关键词： iron deficiency anemia intravenous iron ferric carboxymaltose iron sucrose Hb response early response

The Pichia pastoris enzyme production platform:From combinatorial library screening to bench-top fermentation on residual cyanobacterial biomass

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Journal of Bioresources and Bioproducts 2024年第1期9卷 43-57页

作者： Korbinian Sinzinger Ulrike Obst Samed güner Manuel Döring Magdalena Haslbeck Doris Schieder Volker Sieber Chair of Chemistry of Biogenic Resources Campus Straubing for Biotechnology and SustainabilityTechnical University of MunichStraubing 94315Germany Catalysis Research Center Technical University of MunichGarching 85748Germany SynBiofoundry@TUM Technical University of MunichStraubing 94315Germany School of Chemistry and Molecular Biosciences The University of QueenslandSt.Lucia 4072Australia

The demand for industrial enzymes is continually rising,fueled by the growing need to shift towards more sustainable industrial ***,making efficient enzyme production strains and identifying optimal enzyme expression conditions remains a ***,the production of the enzymes themselves comes with unavoidable impacts,e.g.,the need to utilize secondary ***,we take a more holistic view of bioprocess development and report an integrative approach that allows us to rapidly identify improved enzyme expression and secretion conditions and make use of cyanobacterial waste biomass as feed for supporting Pichia pastoris *** demonstrate these capabilities by producing a phytase secreted by *** that is grown on cyanobacterium hydrolysate and buffered glycerol-complex(BMgY)medium,with genetic expression conditions identified by high-throughput screening of a randomized se-cretion *** our best-performing strain is grown in a fed-batch fermentation on BMgY,we reach over 7000 U/mL in three days.

关键词： Protein secretion Phytase Cyanobacterial biomass Fed-batch fermentation Pichia pastoris

MicroRNAs in hepatocellular carcinoma treatment:Charting the path forward

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World Journal of gastroenterology 2024年第11期30卷 1470-1474页

作者： Hong T Lin Antonio F Alvarez Castaneda Somashekar g Krishna Khalid Mumtaz Division of gastroenterology Hepatology and NutritionDepartment of MedicineThe Ohio State University Wexner Medical CenterColumbusOH 43210United States

MicroRNAs(miRNAs)are recognized for their involvement in the regulation of gene expression and exhibit significant potential in both the prognostic assessment and treatment of hepatocellular carcinoma(HCC).HCC,like other tumors,seldom occurs in isolation;instead,it evolves within a microenvironment featuring oncogenic and tumor-suppressive *** combined with suitable delivery vehicles,miRNA technology provides the capability to directly engage with these elements,thereby hindering tumor formation and *** research in this domain holds the promise of enabling a more efficacious and multi-modal treatment approach for HCC in the near future.

关键词： Hepatocellular carcinoma Tumor microenvironment MicroRNA Mesenchymal stem cell Exosome