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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

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

In-situ construction of grass-like hybrid architecture responsible for extraordinary corrosion performance: Experimental and theoretical approach

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Nano Materials Science 2024年第1期6卷 44-59页

作者： t.Suhartono F.Hazmatulhaq Y.Sheng A.Chaouiki M.P.Kamil Y.g.Ko Materials Electrochemistry group School of Materials Science and EngineeringYeungnam UniversityGyeongsan38541Republic of Korea Research Center for Advanced Materials National Research and Innovation Agency(BRIN)South TangerangBanten15314Indonesia

Despite the engineering potential by the co-existence of inorganic and organic substances to protect vulnerable metallic materials from corrosive environments,both their interaction and in-situ formation mechanism to induce the nature-inspired composite remained less *** present work used three distinctive mercaptobenzazole(MB)compounds working as corrosion inhibitors,such as 2-mercaptobenzoxazole(MBO),2-mercaptobenzothiazole(MBt),and 2-mercaptobenzimidazole(MBI)in a bid to understand how the geometrical structure arising from O,S,and N atoms affected the interaction toward inorganic *** compounds that were used here to control the corrosion kinetics would be interacted readily with the pre-existing MgO layer fabricated by plasma *** phenomenon triggered the nucleation of the root network since MB compounds were seen to be adsorbed actively on the defective surface through the active sites in MB ***,the molecule with twin donor atoms adjacent to the mercapto-sites affected the facile growth of the grass-like structures with‘uniform’distribution via molecular self-assembly,which showed better corrosion performance than those with having dissimilar donor atoms with the inhibition efficiency(η)of 97%*** formation mechanism underlying nucleation and growth behavior of MB molecule was discussed concerning the theoretical calculation of density functional theory.

关键词： Nature-inspired composite Organic-inorganic interaction Corrosion inhibitor Density functional theory Electrochemistry

Heavy metal pollution of river water and eco-friendly remediation using potent microalgal species

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Water Science and Engineering 2024年第1期17卷 41-50页

作者： Amudham Radha Amal Raj Prabhakaran Mylsamy V.Sivasankar B.Sathish Kumar Kiyoshi Omine t.g.Sunitha Phycological Research Laboratory Research Department of BotanyPachaiyappa's College(Affiliated to University of Madras)Chennai 600030India Research Department of Chemistry Pachaiyappa's College(Affiliated to University of Madras)Chennai 600030India Department of Botany Sri Vidya Mandir Arts&Science College(Autonomous)KatteriUthangarai 636902India Department of Civil Engineering School of Engineering.Nagasaki UniversityNagasaki-Daigaku1-14 Bunkyo-machiNagasaki 8528521Japan

Pollution of rivers is mainly caused by anthropogenic activities such as discharge of effluent from industrial facilities,maintenance of sewage/effluent treatment plants,and dumping of solid waste on river *** study dealt with the pollution issues of the Cooum River in the well-known city of Chennai in South *** samples from 27 locations were collected and analyzed for 12 elements,including Ba,B,and Al,as well as heavy metals such as Pb,Cr,Mn,Fe,Co,Ni,Cu,Zn,and *** samples showed levels of these elements that exceeded World Health Organization *** correlation analysis revealed the inter-dependency among elements,and the contribution of each element based on factor loadings showed its percentage contribution compared to *** samples from six significant locations were chosen for remediation with three algae:Chlorella vulgaris,Scenedesmus dimorphus,and Phormedium *** uptake of pollutants led to the continuous growth of algae during the incubation period of 15 d,effectively removing heavy metals from the river *** increasing levels of algal counts and the chlorophyll a content confirmed the algal growth during the incubation period,followed by a declining stage after the incubation *** scanning electron microscopic images of algae before and after the remediation showed no remarkable modification of morphological *** study showed that the uptake of heavy metals using algae is an effective water pollution remediation measure,making the process practicable in the field on a large scale in the near future.

关键词： Heavy metal Cooum river Phycoremediation Microalgae Factor analysis

Paper Analytical Device for the Colourimetric Detection of Alkaline Phosphatase in Serum and Saliva

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Journal of Analysis and testing 2024年第3期8卷 385-394页

作者： D.Alageswari A.LakshmiDevi P.E.Resmi P.V.Suneesh AarathiPradeep t.g.SatheeshBabu Department of Chemistry Amrita School of Physical Sciences Coimbatore Amrita Vishwa Vidyapeetham Amrita Biosensor Research Lab Amrita School of Engineering Coimbatore Amrita Vishwa Vidyapeetham Amrita Biomedical Engineering Centre Amrita School of Engineering Coimbatore Amrita Vishwa Vidyapeetham

A paper analytical device (PAD) was developed for the colourimetric estimation of alkaline phosphatase (ALP). ALP catalyzes the hydrolysis of disodium phenyl phosphate (DSPP) to phenol, which then undergoes oxidative coupling with4-aminoantipyrine (4-AAP) producing a reddish brown-coloured quinone imine. the colourimetric reaction tested in solution has been translated onto a PAD for the point of care (PoC) testing of ALP. A uniform colour was obtained in 25 min with the introduction of ALP onto the reagent drop cast paper device. the images obtained by scanning the PAD were processed using ImageJ software. the colour intensity obtained by image processing was proportional to the concentration of ALP present in the sample. ALP in serum and saliva samples were tested using the PAD in the range of 0 to 528 U/L and0 to 187 U/L, respectively. the interference studies revealed that the PAD was selective to ALP in the presence of other biomolecules. the PAD exhibited a limit of detection (LOD) of 3.3 U/L and a sensitivity of 48.36 a.u/Log(U/L) for serum ALP and LOD of 1.69 U/L and a sensitivity of 28.5 a.u/Log (U/L) for salivary ALP. the PAD showed good agreement with the clinical methods for real samples.

关键词： Alkaline phosphatase Colourimetry ImageJ Paper analytical device Point of care testing

Preparation of microparticles and nanoparticles using membrane-assisted dispersion,micromixing,and evaporation processes

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Particuology 2024年第1期84卷 30-44页

作者： goran t.Vladisavljevic Chemical Engineering Department Loughborough UniversityLoughboroughLeicestershire LE113TUUnited Kingdom

Synthetic microporous membranes are increasingly used for energy-efficient and controlled production of micro-and nanoparticles and micro-and nanoemulsions with tuneable morphology and physico-chemical properties through various micromixing,emulsification,and evaporation *** emul-sification processes,the membrane pores are used for dispersed phase injection and size-controlled generation of droplets and droplet-templated *** micromixing processes,membrane is utilised as a micromixer for mixing two miscible liquids,usually solvent and antisolvent-rich solutions,which leads to the creation of supersaturation and subsequent nanoprecipitation or *** mem-brane evaporation processes,membrane is used to prevent phase dispersion while allowing efficient molecular diffusion of solvent and/or antisolvent vapour through gas-filled *** dispersion processes can be operated continuously by decoupling shear stress on the membrane surface from cross flow using tube insets,flow pulsations,swirling flow,membrane oscillations or membrane *** generation and solidification can be performed continuously in a single pass by connecting membrane module with a downstream *** dispersion processes can be used for pro-duction of nanoparticles such as nanovesicles(liposomes,micelles,ethosomes,and niosomes),nanogels,polymeric,lipid and metallic nanoparticles,and *** main advantages of membrane-assisted particle generation are in low energy consumption,controlled geometry and hydrodynamic conditions at the microscale level,flexible throughput due to modular and scalable design of membrane devices,and a wide choice of available microporous membranes with various wall porosities,wetta-bilities,pore sizes,and pore morphologies to suit different applications.

关键词： Nanoparticles Microparticles Nanoemulsions Microemulsions Microporous membrane Crystallisation Flash nanoprecipitation Emulsification Zero liquid discharge

Late Ordovician Mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： David A.t.Harper Palaeoecosystems group Department of Earth SciencesDurham University

the Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. these symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel Cam Ali günen Iskenderun technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

Excellent photoluminescence and electrochemical properties of Sm^(3+) doped Ca_(2)MgSi_(2)O_(7) nanophosphor:Display and electrochemical sensor applications

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Journal of Rare Earths 2024年第6期42卷 1046-1055,I0002页

作者： R.B.Basavaraj K.Sureshkumar D.P.Aarti M.B.Madhusudana Reddy g.Nagaraju t.Ramakrishnappa g.R.Navyashree K.R.Venkatesha Babu K.S.Hemalatha Department of Physics BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry BMS Institute of Technology and ManagementBangalore560064India Department of Chemistry School of Applied SciencesREVA UniversityBangalore560064India Energy Materials ResearchLaboratory Department of ChemistrySiddaganga Institute of TechnologyTumakuru57203KarnatakaIndia School of Physical Sciences REVA UniversityBangalore560057Indi Department of Physics Govt.Science CollegeBengaluru560001India Department of Physics Maharani Science College for WomenMaharani Cluster UniversityBengaluru560001India

A series of orange-red light emitting Ca_(2)MgSi_(2)O_(7):Sm^(3+)nanopowders were fabricated via low-cost ecofriendly green combustion technique using Aloe vera gel as *** phase purity of the samples were confirmed by the powder X-ray diffraction(PXRD)*** single-phase tetragonal structure is observed from the PXRD results with no additional impurity *** band gap energy of the fabricated powders was estimated by diffuse reflectance spectra(DRS)and is found to be in the range of 4.01-5.98 eV.A high resolution scanning electron microscope(SEM)was used to study the morphological behaviour of the ***-like structures are observed from the SEM *** particle size was evaluated by transmission electron microscopy(tEM)and is found to be~50 *** interplanar distance is found to be 0.53 *** properties were systematically studied in *** phosphors are successfully excited at 403 nm NUV light,producing reddish-orange characteristic *** emission peaks are centered at 558(^(4)g_(5/2)→^(6)H_(5/2)),607(^(4)g_(5/2)→^(6)H_(7/2))and 645 nm(^(4)g_(5/2)→^(6)H_(9/2)),*** the observed peaks the red emanation(^(4)g_(5/2)→^(6)H_(7/2))is stronger than the orange emission(^(4)g_(5/2)→^(6)H_(5/2))in the current *** photoluminescent concentration quenching is noticed above 5 mol%Sm^(3+)ion doping *** dipole-dipole interaction resulting in cross relaxation is found to be the principal cause of concentration quenching *** color features such as Commission Internationale de I’Eclairage(CIE)and correlated color temperature(CCt)were studied in *** optimized chromaticity coordinates were estimated to be(0.6363,0.3632),which fall in the reddish-orange *** average CCt value obtained is 3362 *** average color purity is found to be~82%.Sm^(3+)incorporated Ca_(2)MgSi_(2)O_(7) samples are possible contender for single white light generation commercial candidates owing to

关键词： green combustion Photoluminescence Orange-red emission Color purity Sensors Rare earths