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Current understanding of the origin of equiaxed grains in pure metals during ultrasonic solidification and a comparison of grain formation processes with low frequency vibration,pulsed magnetic and electric-current pulse techniques

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Journal of Materials Science & Technology 2021年第6期65卷 38-53页

作者： Nagasivamuni Balasubramani Gui Wang david h.st john Matthew S.Dargusch Centre for Advanced Materials Processing and Manufacturing(AMPAM) School of Mechanical and Mining EngineeringUniversity of QueenslandSt Lucia

The formation of fine,non-dendritic equiaxed grains throughout a casting without the addition of refiners(*** of alloy chemistry),is made possible by using ultrasonic,magnetic or pulsed magnetic and electric current pulse *** dominant mechanisms proposed for the grain refinement produced during the application of an external field are cavitation phenomena assisted nucleation or fragmentation of dendrites(ultrasonic field),wall crystals arising from the cold surface of the mould(electric current pulse,magnetic and pulsed magnetic fields).In all these cases fluid flow provides an additional contribution(*** temperature gradients,growth rate and remelting of dendrites)to maintaining an equiaxed grain *** origin of equiaxed grains under an external field also depends on the casting conditions(volume and shape of casting)and the type of alloy other than the mechanisms specific to a particular *** current work aims to provide a detailed understanding of the various factors and mechanisms that influence the grain refinement achieved during the solidification of pure metals(magnesium and zinc)subjected to Ultra Sonic Treatment(Ust).The role of the temperature range of Ust application,time duration and an unpreheated sonotrode are examined with respect to the origin,evolution of equiaxed grain structure,morphology and the columnar to equiaxed *** origin of grains was analysed from three fundamental aspects that contribute to refinement(i)heterogeneous nucleation(ii)fragmentation of existing dendrites and(iii)grains produced from the colder surfaces(arising from mould walls or vibrating surfaces as wall crystals).A comparison of Ust refinement with mechanical,low-frequency vibration,electric current pulse and magnetic field solidification of pure metals has also been provided to highlight the importance of the cold surfaces(sonotrode and mould wall)in influencing grain refinement.

关键词： Ultrasonic treatment Grain refinement Equiaxed grains Magnesium Zinc Solidification

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A comparative study of the role of solute,potent particles and ultrasonic treatment during solidification of pure Mg,Mg-Zn and Mg-Zr alloys

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Journal of Magnesium and Alloys 2021年第3期9卷 829-839页

作者： Nagasivamuni Balasubramani Gui Wang Mark A.Easton david h.st john Matthew S.Dargusch Centre for Advanced Materials Processing and Manufacturing(AMPAM) School of Mechanical and Mining EngineeringThe University of QueenslandBrisbane 4072Australia School of Engineering RMIT UniversityCarlton3053 VICAustralia

Ultrasonic treatment(Ust)applied during the solidification of pure Mg,eutectic(Mg-Zn)and peritectic(Mg-Zr)alloys was investigated in order to explore the grain refinement *** dependent grain refinement is observed in pure Mg where decreasing the superheat temperature(at which Ust is applied from above the melting temperature,TM)from 100℃to 40℃produces significant refinement with a uniform grain *** presence of solute reduces the temperature dependence of the Ust refinement and excellent grain refinement is obtained regardless of the superheat temperature(100℃or 40℃)and even with the use of preheated sonotrode in the Mg-6 wt.%Zn alloy.A further improvement in grain refinement is achieved when the alloy contains potent particles that introduce additional nucleation of grains in Mg-0.5 and 1.0 wt.%Zr alloys(producing an average grain size of≤100μm).At 40℃superheat,Ust of Mg-Zn alloys produces excellent refinement(average grain sizeh non-dendritic grains,which is normally achieved only with the addition of grain refining master alloy in the as-cast *** enhanced refinement observed in the eutectic alloy is explained through the undercooling imposed by a relatively cold sonotrode combined with high frequency vibrations and acoustic *** advantages of using a cold sonotrode,a low superheat and solute are demonstrated for achieving significant refinement during solidification of Mg alloys under Ust without or with a lower addition of grain refining master alloys.

关键词： Grain refinement Mg-Zn alloy Mg-Zr alloy Ultrasonic treatment Interdependence Model Solidification

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Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

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Neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： Carina hromada Patrick heimel Markus Kerbl LászlóGál Sylvia Nürnberger Barbara Schaedl James Ferguson Nicole Swiadek Xavier Monforte Johannes C.heinzel Antal Nógrádi Andreas h.Teuschl-Woller david hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian Cluster for Tissue Regeneration ViennaAustria Ludwig Boltzmann Institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University Clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tNGCs). however, the use of tNGCs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tNGC would help eliminate necrotic processes and lead to improved regeneration. In this study, we reported the application of macroscopic holes into the tubular walls of silk-based tNGCs and compared the various features of these improved silk^(+) tNGCs with the tubes without holes(silk^(–) tNGCs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and h.stological analyses, we were able to prove that the use of silk^(+) tNGCs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tNGCs at 7 weeks postoperatively. In the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tNGCs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tNGCs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

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Functional origins of the vertebrate cerebellum from a sensory processing antecedent

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Current Zoology 2010年第3期56卷 277-284页

作者： john MONTGOMERY david BODZNICK Leigh Marine Laboratory and School of Biological Sciences University of Auckland Department of Biology Wesleyan University

The structure of the cerebellar cortex is remarkably similar across vertebrate phylogeny. It is well developed in basaljawed fishes, such as sharks and rays with many of the same cell types and organizational features found in other vertebrategroups, including mammals. In particular, the lattice-like organization of cerebellar cortex (with a molecular layer of parallel fibres,interneurons, spiny Purkinje cell dendrites, and climbing fires) is a common defining characteristic. In addition to the cerebellarcortex, fishes and aquatic amphibians have a variety of cerebellum-like structures in the dorso-lateral wall of the *** structures are adjacent to, and in part, contiguous with, the cerebellum. They derive their cerebellum-like name from thepresence of a molecular layer of parallel fibers and inhibitory interneurons, which has striking organizational similarities to themolecular layer of the cerebellar cortex. however, these structures also have characteristics which differ from the cerebellum. Forexample, cerebellum-like structures do not have climbing fibres, and they are clearly sensory. They receive direct afferent inputfrom peripheral sensory receptors and relay their outputs to midbrain sensory areas. As a consequence of this close sensory association,and the ability to characterise their signal processing in a behaviourally relevant context, good progress has been made indetermining the fundamental processing algorithm in cerebellar-like structures. In particular, we have come to understand thecontribution to signal processing made by the molecular layer, which provides an adaptive filter to cancel self-generated noise inelectrosensory and lateral line systems. Given the fundamental similarities of the molecular layer across these structures, coupledwith evidence that cerebellum-like structures may have been the evolutionary antecedent of the cerebellum, we address the question:do both share the same functional algorithm? [Current Zoology 56 (3):

关键词： Origin Vertebrate Cerebellum

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Transport Modelling for EAst with LhRF and NBI

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Plasma Science and Technology 2009年第4期11卷 417-421页

作者：周登 holger st.john 胡业民李国强任启龙欧靖 Institute of Plasma Physics Chinese Academy of Sciences Centre for Magnetic Fusion Theory Chinese Academy of Sciences General Atomics

Lower hybrid simulation code （LSC） is integrated into transport code ONETWO to model discharges of EAst with heating and current drive using both lower hybrid wave and neutral beam injection. To test the integration, the current profiles driven by both lower hybrid wave and neutral beam injection are presented for a given equilibrium and sample density and temperature profiles before carrying out a time advancing simulation. For a steady state h-mode discharge, the temperature profiles are evolved using GLF23 transport model with a boundary value specified at the normalized minor radius pN = 0.9. A case of steady state with non-inductively driven current accounting for up to 80% is presented.

关键词： ONETWO LSC EAst modeling

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Petrology,geochronology,and geophysical characterization of Mesoproterozoic rocks in central Illinois,USA

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Geoscience Frontiers 2020年第2期11卷 581-596页

作者： Jared T.Freiburg john hMcBride david hMalone hannes ELeetaru Illinois state Geological Survey Prairie Research InstituteUniversity of Illinois at Urbana-Champaign615 E.Peabody DriveChampaignIL 61820USA University of Greifswald Institute of Geography and GeologyFriedrich-Ludwig-Jahn Str.17aD-17489 GreifswaldGermany Department of Geological Sciences Brigham Young UniversityProvoUT84602USA Department of Geography Geologyand the EnvironmentCampus Box 4400Illinois State UniversityNormalIL61790-4400USA

The Precambrian basement rocks of the Eastern Granite-Rhyolite Province(EGRP)in central Illinois(midcontinent region of North America)exhibit a complex h.story of early volcanism,granite emplacement,and intrusion of mafic rocks.A comprehensive suite of dedicated petrographic analyses,geophysical logs,and drill core from four basement-penetrating wells,two-dimensional and three-dimensional seismic reflection data,and U-Pb age data from the Illinois Basin–Decatur Project(IBDP)and Illinois Carbon Capture storage(ICCS)Project site provide new constraints for interpreting the Precambrian basement of the Illinois *** new data reveal the basement to be compositionally and structurally complex,having typical EGRP felsic volcanic rocks intruded by the first reported gabbro in the Precambrian basement in ***(n?29)from rhyolite give a U-Pb weighted mean average age of 14679 ***(n?3)from a gabbro dike that intrudes the rhyolite yield a concordia age of 107312 Ma,which corresponds to Grenville-age extension and represents the first Grenville-age rock in Illinois and in the EGRP.A high-resolution three-dimensional seismic reflection volume,coincident with the four wells,provides a context for interpreting the petrological data and implies a high degree of heterogeneity for basement rocks at the IBDP–ICCS site,as also shown by the drill *** occurrence of Grenville-age gabbro is related to a prominent bowl-like structure observed on local two-dimensional seismic reflection profiles and the three-dimensional volume that is interpreted as a deep-seated mafic sill ***,heterogeneities such as the brecciated EGRP rhyolite and later gabbro intrusion observed in the basement lithology at the IBDP–ICCS may reflect previously unknown distal elements of the 1.1 Ga Midcontinent Rift in the EGRP and more likely Grenville-age extension.

关键词： Eastern granite-rhyolite province Mesoproterozoic Carbon storage Reflection seismology Zircon U-Pb geochronology Illinois

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Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer

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World Journal of Gastrointestinal Oncology 2014年第4期6卷 83-97页

作者： Ganepola AP Ganepola Joel Nizin john R Rutledge david h Chang Center for Cancer Research and Genomic Medicine The Daniel and Gloria Blumenthal Cancer Center Department of Surgery The Valley Hospital

Early screening for colorectal cancer(CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. however, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is anappealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.

关键词： Colorectal neoplasms Early detection of cancer Colonoscopy Biological markers Blood Messenger RNA MicroRNA Long non-coding RNA DNA methylation Microsatellite instability Loss of heterozygosity high-throughput nucleotide sequencing Mass spectrometry Real-time polymerase chain reaction Microarray analysis

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Selective toxicity of hydroxyl-rich carbon nanodots for cancer research

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Nano Research 2018年第4期11卷 2204-2216页

作者： Tak h. Kim Joseph P. Sirdaarta Qian Zhang Ehsan Eftekhari James st. john Derek Kennedy Ian E. Cock Qin Li Queensland Micro and Nano Technology Center & School of Engineering Griffith University 170 Kessels Rd Nathan OLD 4111 Australia Australian Rivers Institute & School of Natural Sciences Griffith University 170 Kessels Rd Nathan QLD 4111 Australia Griffith Institute for Drug Discovery Gfiffith University 46 Don Young Rd Nathan QLD 4111 Australia Menzies health Institute Queensland Griffith University Parkland Drive Southport QLD 4222 Australia

The toxicity of nanoparticles in a biological system is an integration of effects arising from surface functionali~ particle size, ionic dissolution, etc. This complexity suggests that generalization of a material＇s toxicity may be inappropriate. Moreover, from a medicinal point of view, toxicity can be used for treatment of malignant cells, such as cancer. In this stud~ highly biocompatible carbon nanodots （gCDs） were synthesized by reacting citric acid and urea in glycerol, which resulted in abundant hydroxyl functional groups on the particle surface. gCDs show excitation-dependent photoluminescence but with bright green to yellow emission. Importantly, a series of toxicity assessments showed that as-synthesized gCDs possessed exceptional biocompatibilities to various biological entities including 18 bacteria species, Petunia axillaris seedlings, and Artemia franciscana nauplii. Furthermore, the particles were shown to have low to no toxic effects on human embryonic kidney （hEK-293）, breast （MCF-7）, and oral squamous （CAL-27） carcinoma cell lines. Of particular interest, the gCDs displayed antiproliferative activities against ovarian choriocarcinoma cells （JAr/Jeg-3 cell lines）, which may be further explored for cancer drug discovery.

关键词： carbon nanodots nanotoxicity fluorescence choriocarcinoma cells thioredoxin reductase

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Characterization of the proteases in the midgut of the xylophagous larvae of Oemona hirta （Coleoptera： Cerambycidae）

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Insect Science 2009年第5期16卷 381-386页

作者： Brian david Shaw john Tane Christeller The New Zealand Institute of Plant and Food Research Palmerston North New Zealand

The protein digestive capability of the larvae of the longhorn beetle （Oemona hirta, Coleoptera： Cerambycidae, Fabricius, 1775） was investigated. This species feeds only on wood where there is a high proportion of vascular tissue. The ph of the midgut, the major digestive organ, was alkaline and protein hydrolysis was maximal at alkaline ph. Use of specific synthetic peptide substrates showed that the major protease activities were the endopeptidases, trypsin and chymotrypsin-like activity, and the exopeptidase, leucine aminopeptidase and the ph curves corresponded to that with protein substrate. studies using a range ofserine protease inhibitors as well as specific inhibitors ofmetalloproteases, cysteine proteases and aspartate proteases confirmed a serine protease-based digestive system similar to earlier reports of sapwood-feeding Cerambycids. Control of these insect pests using protease inhibitors is discussed.

关键词： chymotrypsin digestion Oemona hirta trypsin xylophagy

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Proteomic and metabolomic profiling underlines the stage- and time-dependent effects of high temperature on grape berry metabolism

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Journal of Integrative Plant Biology 2020年第8期62卷 1132-1158页

作者： david Lecourieux Christian Kappel stéphane Claverol Philippe Pieri Regina Feil john E.Lunn Marc Bonneu Lijun Wang Eric Gomès Serge Delrot Fatma Lecourieux UMR1287 EGFV INRAEBordeaux Sciences AgroBordeaux UniversityISVV33140 Villenave d'OrnonFrance Institut of Biochemistry and Biology Potsdam UniversityD-14476 PotsdamGermany Proteome Platform Bordeaux Functional Genomic CenterBordeaux University33076 BordeauxFrance Max Planck Institute of Molecular Plant Physiology 14476 PotsdamGolmGermany Institute of Botany the Chinese Academy of SciencesBeijing 100093China UMR1287 EGFV CNRSINRAEBordeaux Sciences AgroBordeaux UniversityISVV33140 Villenave d'OrnonFrance

Climate change scenarios predict an increase in mean air temperatures and in the frequency,intensity,and length of extreme temperature events in many wine-growing regions *** elevated temperature has detrimental effects on berry growth and composition,it threatens the economic and environmental sustainability of wine *** Cabernet Sauvignon fruit-bearing cuttings,we investigated the effects of high temperature(hT)on grapevine berries through a label-free shotgun proteomic analysis coupled to a complementary metabolomic *** the 2,279 proteins identified,592 differentially abundant proteins were found in berries exposed to *** gene ontology categories“stress,”“protein,”“secondary metabolism,”and“cell wall”were predominantly altered under *** temperatures strongly impaired carbohydrate and energy metabolism,and the effects depended on the stage of development and duration of *** amounts correlated poorly with protein expression levels in hT berries,highlighting the value of proteomic studies in the context of heat ***,this work reveals that hT alters key proteins driving berry development and ***,we provide a list of differentially abundant proteins that can be considered as potential markers for developing or selecting grape varieties that are better adapted to warmer climates or extreme heat waves.

关键词： metabolism extreme high

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