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Blending with transition metals improves bioresorbable zinc as better medical implants

Bioactive materials 2023年第2期20卷 243-258页

作者： Yingchao Su Jiayin Fu Juncen Zhou Elias Georgas Shaokang Du Yi-Xian Qin Yadong Wang Yufeng Zheng Donghui Zhu Department of Biomedical Engineering Stony Brook UniversityStony BrookNYUSA Nancy E.and Peter C.Meinig School of Biomedical Engineering Cornell UniversityIthacaNYUSA Department of Cardiology Sir Run Run Shaw HospitalZhejiang UniversityHangzhouZhejiangChina Academy for Advanced Interdisciplinary Studies Peking UniversityBeijingChina School of Materials Science and Engineering Peking UniversityBeijingChina

Zinc(Zn)is a new class of bioresorbable metal that has potential for cardiovascular stent material,orthopedic implants,wound closure devices,***,pure Zn is not ideal for these applications due to its low mechanical strength and localized degradation *** is the most common/effective way to overcome this ***,the choice of alloying element is crucial to ensure the resulting alloy possesses sufficient mechanical strength,suitable degradation rate,and acceptable ***,we proposed to blend selective transition metals(i.e.,vanadium-V,chromium-Cr,and zirconium-Zr)to improve Zn’s *** selected transition metals have similar properties to Zn and thus are beneficial for the metallurgy process and mechanical ***,the biosafety of these elements is of less concern as they all have been used as regulatory approved medical implants or a component of an implant such as Ti6Al4V,CoCr,or Zr-based dental *** study showed the first evidence that blending with transition metals V,Cr,or Zr can improve Zn’s properties as bioresorbable medical *** addition,three in vivo implantation models were explored in rats:subcutaneous,aorta,and femoral implantations,to target the potential clinical applications of bioresorbable Zn implants.

关键词： Degradation Cardiovascular Orthopedic Subcutaneous Antibacterial

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Density Functional Theory Study of Surface Stability and Phase Diagram of Orthorhombic CsPbI3

arXiv

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arXiv 2024年

作者： Li, Kejia Wang, Mengen Department of Electrical and Computer Engineering and Materials Science and Engineering Program SUNY BinghamtonNY13902 United States

CsPbI3 has been recognized as a promising candidate for optoelectronic device applications. To further improve the efficiency of the devices, it is imperative to better understand the surface properties of CsPbI3, which affect charge carrier transport and defect formation properties. In this study, we perform density functional theory calculations to explore the stability of the (001), (110), and (100) surfaces of orthorhombic CsPbI3, considering different stoichiometries and surface reconstructions. Our results show that, under the chemical potentials confined by the thermodynamically stable region of bulk CsPbI3, the CsI-terminated surfaces of (001) and (110) and the stoichiometric surface of (100) are stable. Among these three surfaces, the CsI-terminated (110) surface has the lowest surface energy and no mid-gap states, which benefits the transport properties of the material. © 2024, CC BY-NC-SA.

关键词： Stoichiometry

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Effect of Heat Treatments on Microstructure and Mechanical Properties of Fe-Mn-Ni-Al-Gd Shape Memory Alloy

Effect of Heat Treatments on Microstructure and Mechanical P...

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2023 Sharjah International Conference on Physics of Advanced materials, SICPAM 2023

作者： Mustafa, Faisal Egilmez, Mehmet Abuzaid, Wael El-Khatib, Sami Department of Physics American University of Sharjah Sharjah26666 United Arab Emirates Materials Science and Engineering Program American University of Sharjah Sharjah26666 United Arab Emirates Department of Mechanical Engineering American University of Sharjah Sharjah26666 United Arab Emirates

There are significant scientific and industrial efforts to develop and optimize Iron-based shape memory alloys (SMA) such as FeMnNiAl for cost-sensitive applications. This alloy system shows shape memory and superelastic properties across a large temperature range. However, many studies have pointed out the need for rather complex thermo-mechanical treatments for the optimization of the SMA properties. In addition, works considering the effects of alloying on the development of microstructures that are more conducive to pseudo-elasticity in this system remain limited. Hence, systematic studies aiming at the investigation of the microstructural evolution of the FeMnNiAl(Gd) system are of great interest. In this study, solution heat treatment is done to tune the microstructure for optimum mechanical properties. The effect of phase distribution on mechanical properties is investigated at different heat treatments. Whereas cyclic heat treatment induced abnormal grain growth (AGG) in all samples, so large grains were obtained. The phase variation and elemental composition are analyzed by X-ray diffraction and Energy Dispersive Spectroscopy, respectively. The microstructure and phase distribution are observed using Scanning Electron Microscope and then related to the microhardness results. The microstructure has a good correlation with mechanical properties where the fine distribution of phases results in a higher hardness number. © Published under licence by IOP Publishing Ltd.

关键词： Microstructure

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Study of bioaerosol disinfection kinetics and application of nonlinear regression modeling for optimization of TiO2-based photocatalytic disinfection process

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Nanotechnology for Environmental engineering 2023年第4期8卷 911-922页

作者： Nishad, Vartika Mandal, Chinmoy Sahu, Manoranjan Aerosol and Nanoparticle Technology Laboratory Environmental Science and Engineering Department Indian Institute of Technology Bombay 507 Powai Mumbai400076 India Interdisciplinary Program in Climate Studies Indian Institute of Technology Bombay Mumbai400076 India Centre for Machine Intelligence and Data Science Indian Institute of Technology Bombay Mumbai400076 India

Bacteria and viruses are some of the major sources of indoor air pollution. Many strategies are utilized to control indoor biopollutants. Among the new emerging technologies, this work focuses on the photocatalytic oxidation process and application of disinfection models to optimize the photocatalytic process in bioaerosol control. The kinetics of bioaerosol disinfection was investigated in the photocatalytic process with nonlinear regression analysis for Serratia marcescens and E. coli bacteria. The Chick–Watson model was found suitable and was applied for determination of the inactivation kinetics. The inactivation rate constant k’ was found to be 0.0038 min−1 for S. marcescens and 0.09 min−1 for E. coli. The outcomes showed that in the process of disinfection kinetics of bioaerosols, pseudo-first-order kinetics fits well. With nonlinear regression analysis, a model was developed based on functional parameters such as UV intensity (20 to 100 W/m2), relative humidity (30 to 85%) and air velocity (37 to 112 ft/min) for S. marcescens and TiO2 loading (960 and 1516 mg/m2), UV intensity (0.5 to 3.4 mW/cm2) and relative humidity (51 to 85%) for E. coli. For E. coli overall inactivation was found to increase with an increase in TiO2 loading, RH or UV intensities. The inactivation rate of S. marcescens increased with an increase in UV intensity;however, it was found to decrease at very high or low values of relative humidity and air velocity. Hence, the optimum values for relative velocity were found to be 50% and air velocity of 74 ft/min for S. marcescens. The rate expressions derived for both data can be utilized for predicting and optimizing the disinfection rate at different conditions. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

关键词： Titanium dioxide

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Impact of spatial distribution of light intensity on disinfection kinetics of Mycobacterium smegmatis and E. coli using TiO2-based photocatalyst

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Nanotechnology for Environmental engineering 2023年第2期8卷 567-579页

作者： Mandal, Chinmoy Nishad, Vartika Sahu, Manoranjan 507 Aerosol and Nanoparticle Technology Laboratory Environmental Science and Engineering Department Indian Institute of Technology Bombay Powai Mumbai400076 India Interdisciplinary Program in Climate Studies Indian Institute of Technology Bombay Mumbai400076 India Centre for Machine Intelligence and Data Science Indian Institute of Technology Bombay Mumbai400076 India

Photocatalysis using various nanomaterials of different characteristics has been investigated with various metrics for achieving optimal efficiency. However, the spatial distribution of light intensities from the light source, a key factor in photocatalysis process and the selection of an appropriate kinetic model for explaining disinfection characteristics of different microorganisms have not been given ample consideration. In this study, a suitable model has been applied to identify spatial distribution of light based on the light source used and applied in the kinetic models to identify the disinfection rate. Disinfection efficiencies of nanoparticles (TiO2 and Cu-doped TiO2) with different light intensities on gram-positive bacteria, Mycobacterium smegmatis and gram-negative bacteria E. coli was evaluated. The kinetic study revealed that Mycobacterium smegmatis fits well with Chick–Watson model, while E. coli fits well with delayed Chick–Watson model. The rate constants (k) were found to be 0.013 min−1 (TiO2), 0.021 min−1 (3%Cu–TiO2) and 0.020 min−1 (Cu2+) for Mycobacterium and 0.019 min−1 (TiO2) for E. coli. From model evaluation, light intensity decreased exponentially from 3.07 µW cm−2 (3 cm) to 0.98 µW cm−2 (6 cm) and 0.10 µW cm−2 (25 cm) resulting in a sharp decline in the inactivation potential;however, the effect was insignificant beyond 10 cm. On doubling the intensity, disinfection efficiency increased by 1.6 log CFUml−1 (TiO2) and 2.4 log CFU ml−1 (Cu–TiO2), but with one-fourth of intensity it decreased by 1.2 log CFUml−1 (TiO2) and 1.8 log CFUml−1 (Cu–TiO2). Therefore, by optimizing the combination of nanoparticles like TiO2 and Cu, light intensity at 6.14 µW cm−2 and optimal spatial distribution of the light source at 3 cm, increased efficiency of microbial disinfection could be achieved. Thus, this study provides an approach to optimize photocatalytic parameters with inclusion of spatial distribution of light intensity for enhancing the photocatalyt

关键词： Titanium dioxide

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Temperature-Responsive and Passive Wireless Mechanical Metamaterial Sensors 14

Temperature-Responsive and Passive Wireless Mechanical Metam...

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14th International Workshop on Structural Health Monitoring: Designing SHM for Sustainability, Maintainability, and Reliability, IWSHM 2023

作者： Naidu, Vishnu R. Park, Yujin Loh, Kenneth J. Materials Science and Engineering Program University of California La Jolla San DiegoCA92093 United States Department of Structural Engineering University of California La Jolla San DiegoCA92093 United States

ISBN: (纸本)9781605956930

Knowing the location and environmental conditions of sailors that have fallen overboard can greatly facilitate open water search and rescue operations. Currently, active sensors that trigger an alarm when a sailor falls overboard exist, and it works by detecting a loss of signal from a transmitter. However, their applications have been limited because of the dependence on a working battery, as well as the fact that sailor location cannot be tracked beyond the one-time loss-of-signal event. In this study, a passive, person-overboard sensing concept is proposed, and the focus is to demonstrate monitoring of seawater conditions. The passive sensor was designed by incorporating a temperature-responsive hydrogel with an auxetic star pattern unit cell geometry, which transforms from a two- to three-dimensional geometry when immersed in low temperature liquid. First, the passive sensor was formed by incorporating a temperature-responsive hydrogel at opposite ends of the star pattern. The time-dependent swelling and de-swelling behavior of the copolymer hydrogel was characterized to understand the mechanical strains induced after exposure to low temperature water. Second, the design of the star pattern geometry was optimized, and artificial imperfections in the form of notches were employed to allow shape transformation to take place at appropriate and minimal applied strains. The vision is that these shape morphing structures with integrated antennas can serve as passive sensors, which, when interrogated by a remote reader, can be used to monitor how long overboard sailors have been in a low-temperature open sea environment. © 2023 by DEStech Publi cations, Inc. All rights reserved

关键词： Water temperature

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An ultraefficient surface functionalized Ti3C2Tx MXene piezocatalyst: synchronous hydrogen evolution and wastewater treatment

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Journal of materials Chemistry A 2023年第6期12卷 3340-3351页

作者： Lai, Sz-Nian Chen, Winston Yenyu Yen, Chao-Chun Liao, Yin-Song Chen, Po-Han Stanciu, Lia Wu, Jyh Ming Department of Materials Science and Engineering National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan PhD Program in Prospective Functional Materials Industry National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan High Entropy Materials Center National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan Tsing Hua Interdisciplinary Program National Tsing Hua University 101 Section 2 Kuang Fu Road Hsinchu300 Taiwan School of Materials Engineering Purdue University 610 Purdue Mall West LafayetteIN47907 United States Department of Materials Science and Engineering National Chung Hsing University 145 Xingda Road Taichung402 Taiwan

The Ti3C2Tx surface contains hydroxyl groups that can be modified through self-assembled monolayers by using (3-chloropropyl) trimethoxysilane (CPTMS) and fluoroalkylsilane (FOTS). This study demonstrates that an ultrahigh level of piezoelectricity can be achieved by modifying the Si-O bond of organo-silane headgroups in Ti3C2Tx. The theoretical calculation of surface functionalized Ti3C2Tx-FOTS reveals that its Si-O bond causes localized lattice distortion and enhances the noncentrosymmetric structure on the Ti3C2Tx surface. Ti3C2Tx-FOTS exhibits significantly higher butterfly loops than pristine Ti3C2Tx. The calculated rate constant of Ti3C2Tx-FOTS for dye degradation was 0.9 min−1, 15-fold higher than that of Ti3C2Tx-CPTMS and 111-fold higher than that of pristine Ti3C2Tx. The hydrogen evolution rate of Ti3C2Tx-FOTS is 900.46 μmo1 g−1 h−1, three times higher than that of Ti3C2Tx. The bifunctional surface functionalized Ti3C2Tx-FOTS can simultaneously catalyse the hydrogen evolution reaction (HER) and decomposition of wastewater, demonstrating that Ti3C2Tx-FOTS, obtained through the surface engineering of Ti3C2Tx, is a superior piezocatalyst. © 2024 The Royal Society of Chemistry.

关键词： Rate constants

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Effect of Gd, V, and y Alloying on the Corrosion Properties of Fe-Mn-Ni-Al Fe-based Shape Memory Alloy

Effect of Gd, V, and y Alloying on the Corrosion Properties ...

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2023 Sharjah International Conference on Physics of Advanced materials, SICPAM 2023

作者： Mustafa, Faisal Ahmad, Shahbaz Hassan, Arhum Egilmez, Mehmet El-Khatib, Sami Ibrahim, Taleb Department of Physics American University of Sharjah Sharjah26666 United Arab Emirates Materials Science and Engineering Program American University of Sharjah Sharjah26666 United Arab Emirates Department of Chemical Engineering American University of Sharjah Sharjah26666 United Arab Emirates

Shape Memory Alloys (SMA) are widely utilized in numerous industrial applications nowadays. Significant attention has been given to Fe-based SMA in civil engineering applications due to their high strength and reasonable cost. Researchers are striving to improve the corrosion resistance of these alloys so they can be utilized in marine environments. This article focuses on the effect of Gd, V, and Y alloying on FeMnNiAl based SMA. The phases and morphological effects were characterized using X-Ray diffractometer (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). To examine the corrosive nature of the Fe-based SMA system, a potentiodynamic analysis and electrochemical impedance spectroscopy (EIS) tests were performed in 3.5% NaCl solution. Results show that the addition of Gd rare earth metal has improved the overall corrosion efficiency of Fe-based SMAs by 48%. © Published under licence by IOP Publishing Ltd.

关键词： Scanning electron microscopy

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Negative-to-Positive Tunnel Magnetoresistance in van der Waals Fe_(3)GeTe_(2)/Cr_(2)Ge_(2)Te_(6)/Fe_(3)GeTe_(2)Junctions

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Chinese Physics Letters 2023年第7期40卷 51-55页

作者：王子奥张晓敏朱文凯闫法光刘鹏飞袁喆王开友 State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Center for Advanced Quantum Studies and Department of Physics Beijing Normal UniversityBeijing 100875China

The emergent van der Waals magnetic material is a promising component for spintronic devices with novel ***,we report a transition of negative-to-positive magnetoresistance in Fe_(3)GeTe_(2)/Cr_(2)Ge_(2)Te_(6)/Fe_(3)GeTe_(2)van der Waals all-magnetic tunnel junctions with increasing the applied bias voltage.A negative magnetoresistance is observed first in Fe_(3)GeTe_(2)/Cr_(2)Ge_(2)Te_(6)/Fe_(3)GeTe_(2)tunnel junctions,where the resistance with antiparallel aligned magnetization of two Fe_(3)GeTe_(2)electrodes is lower than that with parallel alignment,which is due to the opposite spin polarizations of two Fe_(3)GeTe_(2)*** the bias voltage increasing,the spin polarization of the biased Fe_(3)GeTe_(2)electrode is changed so that the spin orientations of two Fe_(3)GeTe_(2)electrodes are the *** experimental observations are supported by the calculated spin-dependent density of states for Fe_(3)GeTe_(2)electrodes under a finite *** significantly bias voltage-dependent spin transport properties in van der Waals magnetic tunnel junctions open a promising route for designing electrical controllable spintronic devices based on van der Waals magnets.

关键词： (3) alignment opposite

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Recent advances in electronic devices for monitoring and modulation of brain

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Nano Research 2021年第9期14卷 3070-3095页

作者： Yong Won Kwon Yoon Sun Jun Young-Geun Park Jiuk Jang Jang-Ung Park Nano Science Technology Institute Department of Materials Science and EngineeringYonsei UniversitySeoul 03722Republic of Korea Center for Nanomedicine Institute for Basic Science(IBS)Seoul 03722Republic of Korea Graduate Program of Nano Biomedical Engineering(NanoBME) Advanced Science InstituteYonsei UniversitySeoul 03722Republic of Korea

The brain is actuated by billions of neurons with trillions of interconnections that regulate human *** the mechanisms of these systems that induce sensory reactions and respond to disease remains one of the greatest challenges in science,engineering,and *** advances in nanomaterials and nanotechnologies have led to the extensive research of electronic devices for brain interfaces to better understand the neural activities of the brains complex nervous *** development of sensor devices for monitoring the physiological signals of the brain related to traumatic injury status has accompanied by the progress of electronic neural probes in *** addition,these neurological and stereotactic surgical revolutions hold immense potential for clinical analysis of pharmacological systems within cerebral ***,we review the progress of electronic devices interfacing with brain in terms of the materials,fabrication technologies,and device *** activity can be measured and modulated by brain probes based on newly developed nanofabrication ***,in vivo pathological monitoring of the brain and pharmacological assessment has been developed in miniaturized and wireless *** also consider the key challenges and prospects for further development,and explore the future directions emerging in the latest research.

关键词： neural interfaces neural recording neuromodulation intracranial pressure monitoring microfluidic drug delivery

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