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Microstructure refinement in biodegradable Zn-Cu-Ca alloy for enhanced mechanical properties,degradation homogeneity,and strength retention in simulated physiological condition

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Journal of Materials Science & Technology 2022年第30期125卷 1-14页

作者： Nan Yang Nagasivamuni Balasubramani jeffrey Venezuela Helle Bielefeldt-Ohmann Rachel Allavena Sharifah Almathami Matthew Dargusch Queensland Centre for Advanced Materials Processing and Manufacturing(AMPAM)School of Mechanical and Mining Engineering The University of QueenslandAdvanced Engineering BuildingBld 49Staff House Rd.St LuciaQLD 4072Australia School of Veterinary Science The University of QueenslandGattonQLD 4343Australia School of Chemistry and Molecular Biosciences The University of QueenslandQLD 4072Australia

Zn-1.0Cu-0.5Ca(TA15)alloy has shown promising characteristics of enhanced mechanical properties and biodegradability for absorbable cardiovascular stents,endovascular devices,and wound closure devices *** this study,the TA15 alloy for bioabsorbable biomedical applications is *** the conventionally cast TA15(TA15-C)alloy,CaZn_(13) phase are present as a large dendritic network with an average size of 73.25±112.84μm,Hot rolling of the TA15-C alloy has broken the long and dendritic network of the CaZn_(13) phases,however,the refined phases are observed as segregations and the distribution is *** segregated CaZn_(13) suffered heavy localised corrosion which lead to poor mechanical properties in the as-fabricated condition and after *** treatment(UST)during casting is identified as an effective technique for the refinement and redistribution of CaZn_(13) particles in TA15 alloy,which successfully reduce the size of the CaZn_(13) phase to 10.91±4.65μm in the as-solidified *** hot rolling,the UST processed TA15(TA15-UST)shows improved mechanical properties due to grain refinement and the reduction in microstructural defects,*** broken CaZn_(13) *** of 8-week immersion corrosion tests showed that both alloys possess very similar corrosion ***,TA15-UST has markedly improved corrosion homogeneity compared to TA15-N which favours the retention of mechanical properties even after prolonged exposure to physiological fluids.

关键词： Biodegradable Zn alloy Peritectic phase refinement In vitro corrosion Mechanical property retention Cytocompatibility

Dynamic material performance of cold-formed steel hollow sections： a state-of-the-art review

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Frontiers of Structural and Civil Engineering 2017年第2期11卷 209-227页

作者： Cameron B. RITCHIE jeffrey A. PACKER Xiao-Ling ZHAO Amin HEIDARPOUR Yiyi CHEN Department of Civil Engineering University of Toronto Toronto Ontario MSS 1A4 Canada Department of Civil Engineering Monash University Victoria 3800 Australia College of Civil Engineering Tongji University Shanghai 200092 China

This paper presents a literature review focused on the material performance of cold-formed, carbon steel, hollow structural sections under impulsive （highly dynamic） loading. Impulsive loading, represented by impact and blast, is characterized by a very rapid, time-dependent loading regime in the affected members and materials. Thus, the effect of high-strain-rate loading is initially reviewed. Next the material toughness, an important energy-absorption property and one measure of a material＇s ability to arrest fracture, is considered by means of studying the Charpy V-notch behavior. The response of hollow sections under axial and lateral impact loading is then reviewed. Studies of blast on hollow sections, most of which fall under the categories of contact/near-field loading or far-field loading are presented. Under large-scale field blast experiments, cold-formed hollow sections have shown excellent behavior. Software for modeling blast loading and structural response, the latter including single degree of freedom analysis and explicit finite element analysis, is described and discussed.

关键词： cold-formed steel hollow structural sections composites impulsive loading impact blast experimentation analysis material properties

Changes in skin levels of two neutotrophins (glial cell line derived neurotrohic factor and neurotrophin-3) cause alterations in cutaneous neuron responses to mechanical stimuli

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生理学报 2008年第5期60卷 584-596页

作者： jeffrey Lawson Sabrina L. Mcllwrath H. Richard Koerber Department of Neurobiology University of Pittsburgh School of Medicine Pittsburgh PA 15261 USA

Neurotrophins are important for the development and maintenance of both high and low threshold mechanoreceptors(HTMRs and LTMRs).In this series of studies,the effects of constitutive overexpression of two different neurotrophins,neurotrophin-3(NT-3) and glial cell line derived neurotrohic factor(GDNF),were *** studies indicated that both of them may be implicated in the normal development of mouse dorsal root ganglion(DRG) *** from mice transgenically altered to overexpress NT-3 or GDNF(NT-3-OE or GDNF-OE mice) in the skin were examined using several physiological,immunohistochemi-cal and molecular *** vivo skin/nerve/DRG/spinal cord and skin/nerve preparations were used to determine the response characteristics of the cutaneous neurons;immunohistochemistry was used to examine the biochemical phenotype of DRG cells and the skin;RT-PCR was used to examine the levels of candidate ion channels in skin and DRG that may correlate with changes in physiological *** GDNF-OE mice,I-isolectin B4(IB4)-immunopositive C-HTMRs(nociceptors),a large percentage of which are sensitive to GDNF,had significantly lower mechanical thresholds than wildtype(WT) *** thresholds for the same cells were not *** sensitivity changes in GDNF-OE mice were correlated with significant increases in acid sensing ion channels 2a(ASIC2a) and 2b(ASIC2b) and transient receptor potential channel A1(TRPA1),all of which are putative mechanosensitive ion *** of NT-3 affected the responses of A-LTMRs and A-HTMRs,but had no effect on *** adapting type 1(SA1) LTMRs and A-HTMRs had increased mechanical sensitivity compared to *** sensitivity was correlated with significant increases in acid-sensing ion channels ASIC1 and *** data indicates that both neurotrophins play roles in determining mechanical thresholds of cutaneous HTMRs and LTMRs and that sensitivity changes involve the ASIC family of pu

关键词：皮肤胶质细胞神经元反应机械性刺激

Machine Learning Chemical Guidelines for Engineering Electronic Structures in Half-Heusler Thermoelectric Materials

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Research 2020年第1期2020卷 978-985页

作者： Maxwell TDylla Alexander Dunn Shashwat Anand Anubhav Jain G.jeffrey Snyder Department of Materials Science and Engineering Northwestern UniversityIL 60208USA Department of Materials Science and Engineering UC BerkeleyCA 94720USA Lawrence Berkeley National Laboratory Energy Technologies AreaCA 94720USA

Half-Heusler materials are strong candidates for thermoelectric applications due to their high weighted mobilities and power factors,which is known to be correlated to valley degeneracy in the electronic band ***,there are over 50 known semiconducting half-Heusler phases,and it is not clear how the chemical composition affects the electronic *** all the n-type electronic structures have their conduction band minimum at either theΓ-or X-point,there is more diversity in the p-type electronic structures,and the valence band maximum can be at either theΓ-,L-,or ***,we use high throughput computation and machine learning to compare the valence bands of known half-Heusler compounds and discover new chemical guidelines for promoting the highly degenerate W-point to the valence band *** do this by constructing an“orbital phase diagram”to cluster the variety of electronic structures expressed by these phases into groups,based on the atomic orbitals that contribute most to their valence ***,with the aid of machine learning,we develop new chemical rules that predict the location of the valence band maximum in each of the *** rules can be used to engineer band structures with band convergence and high valley degeneracy.

关键词： structure valence bands

Effects of Inertia and Viscosity on Single Droplet Deformation in Confined Shear Flow

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Communications in Computational Physics 2013年第3期13卷 706-724页

作者： Samaneh Farokhirad Taehun Lee jeffrey F.Morris Department of Mechanical Engineering City College of City University of New YorkNew YorkNew York 10031USA Department of Chemical Engineering and Levich Institute City College of City University of New YorkNew YorkNew York 10031USA

Lattice Boltzmann simulations based on the Cahn-Hilliard diffuse interface approach are performed for droplet dynamics in viscous fluid under shear flow,where the degree of confinement between two parallel walls can play an important *** effects of viscosity ratio,capillary number,Reynolds number,and confinement ratio on droplet deformation and break-up in moderately and highly confined shear flows are investigated.

关键词： Lattice Boltzmann method droplet deformation confinement

In situ DRIFTS study of photocatalytic CO_(2) reduction under UV irradiation

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Frontiers of Chemical Science and Engineering 2010年第2期4卷 120-126页

作者： jeffrey C.S.WU Chao-Wei HUANG Department of Chemical Engineering Taiwan UniversityTaipei 10617China

Photocatalytic reduction of CO_(2) on TiO_(2) and Cu/TiO_(2) photocatalysts was studied by in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)under UV *** photocatalysts were prepared by sol-gel method via controlled hydrolysis of titanium(IV)*** precursor was loaded onto TiO_(2) during sol-gel procedure.A large amount of adsorbed H_(2)O and surface OH groups was detected at 25℃on the TiO_(2) photocatalyst after being treated at 500℃under air *** and bicarbonate were formed rapidly due to the reaction of CO_(2) with oxygen-vacancy and OH groups,respectively,on TiO_(2) surface upon CO_(2)*** IR spectra indicated that,under UV irradiation,gas-phase CO_(2) further combined with oxygen-vacancy and OH groups to produce more carbonate or *** weak signals of reaction intermediates were found on the IR spectra,which were due to the slow photocatalytic CO_(2) reduction on *** electrons merge with H^(+)ions to form H atoms,which progressively reduce CO_(2) to form formic acid,dioxymethylene,formaldehyde and methoxy as observed in the IR *** well-dispersed Cu,acting as the active site significantly increases the amount of formaldehyde and dioxymethylene,thus promotes the photoactivity of CO_(2) reduction on Cu/TiO_(2).A possible mechanism of the photocatalytic CO_(2) reduction is proposed based on these intermediates and products on the photocatalysts.

关键词： photocatalysis CO_(2) titania in situ infrared spectroscopy Cu/TiO_(2)

microRNAs, an active and versatile group in cancers

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International Journal of Oral Science 2011年第4期3卷 165-175页

作者： jeffrey Liu Min Zheng Ya-ling Tang Xin-hua Liang Qin Yang Department of Biological Sciences University of Delaware Nowak DE 19716 USA State Key Laboratory of Oral Diseases Sichuan University Chengdu 610041 China Department of Oral and Maxillofacial Surgery West China School of Stomatology Sichuan University Chengdu 610041 China Cancer Biology Division School of Medicine Washington University St. Louis MO 63108 USA

microRNAs （miRNAs） are a class of non-coding RNAs that function as endogenous triggers of the RNA interference pathway. Studies have shown that thousands of human protein-coding genes are regulated by miRNAs, indicating that miRNAs are master regulators of many important biological processes, such as cancer development, miRNAs frequently have deregulated expression in many types of human cancers, and play critical roles in tumorigenesis, which functions either as tumor suppressors or as oncogenes. Recent studies have shown that miRNAs are highly related with cancer progression, including initiating, growth, apoptosis, invasion, and metastasis. Furthermore, miRNAs are shown to be responsible for the cancer-related inflam- mation, anti-cancer drug resistance, and regulation of cancer stem ceils. Therefore, miRNAs have generated great interest as a novel strategy in cancer diagnosis and therapy. Here we review the versatile roles of miRNAs in cancers and their potential applications for diagnosis, prognosis, and treatment as biomarkers.

关键词： microRNAs cancer epithelial-mesenchymal transition inflammation cancer stem cells drug resistance

A versatile acoustically active surface based on piezoelectric microstructures

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Microsystems & Nanoengineering 2022年第3期8卷 51-60页

作者： Jinchi Han Mayuran Saravanapavanantham Matthew R.Chua jeffrey H.Lang Vadimir Bulovic Department of Electrical Engineering and Computer Science Massachusetts Institute of TechnologyCambridgeMA 02139USA

We demonstrate a versatile acoustically active surface consisting of an ensemble of piezoelectric microstructures that are capable of radiating and sensing acoustic waves.A freestanding microstructure array embossed in a single step on a flexible piezoelectric sheet of polyvinylidene fluoride(PVDF)leads to high-quality acoustic performance,which can be tuned by the design of the embossed *** high sensitivity and large bandwidth for sound generation demonstrated by this acoustically active surface outperform previously reported thin-flm loudspeakers using PVDF,PVDF copolymers,or voided charged polymers without *** further explore the directivity of this device and its use on a curved *** addition,high-fidelity sound perception is demonstrated by the surface,enabling its microphonic application for voice recording and speaker *** versatility,high-quality acoustic performance,minimal form factor,and scalability of future production of this acoustically active surface can lead to broad industrial and commercial adoption for this technology.

关键词： surface. piezoelectric versatile

Ice Cores as a Source for Antimicrobials:From Bioprospecting to Biodesign

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BioDesign Research 2023年第1期5卷 155-157页

作者： Ying-Chiang jeffrey Lee Bahar Javdan Department of Molecular Biology Princeton UniversityPrincetonNJ 08544USA. Rutgers Robert Wood Johnson Medical School New BrunswickNJ 08901USA.

The golden age has passed for antibiotic discovery,and while some antibiotics are currently in various phases of clinical trials in the United States,many pharmaceutical companies have abandoned antibiotic *** the need for antibiotics,we should expand our horizon for therapeutic mining and can look toward understudied sources such as ice *** cores contain microorganisms and genetic material that have been frozen in time for thousands of *** antibiotics used by these organisms are encoded in their genomes,which can be unlocked,identified,and characterized with modern advances in molecular biology,genetic sequencing,various computational approaches,and established natural product discovery *** synthetic biology can be used in natural product discovery approaches,synthetic biology and bioengineering efforts can also be leveraged in the selection and biodesign of increased compound yields,potency,and ***,we provide the perspective that ice cores can be a source of novel antibiotic compounds and that the tools of synthetic biology can be used to design better antimicrobials.

关键词： stability prospecting companies