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Origin of the current-driven breakdown in vanadium oxides: Thermal versus electronic

Physical Review B 2018年第19期98卷 195144-195144页

作者： I. Valmianski P. Y. Wang S. Wang Juan Gabriel Ramirez S. Guénon Ivan K. Schuller Department of Physics and Center for Advanced Nanoscience University of California San Diego La Jolla California 92093 USA Materials Science and Engineering Program University of California San Diego La Jolla California 92093 USA Department of Physics Universidad de los Andes Bogotá 111711 Colombia Physikalisches Institut-Nano Atomoptics Tubingen Germany

We report the existence of two competing mechanisms in the current-driven electrical breakdown of vanadium sesquioxide (V2O3) and vanadium dioxide (VO2) nanodevices. Our experiments and simulations show that the competition between a purely electronic (PE) mechanism and an electrothermal (ET) mechanism, suppressed in nanoscale devices, explains the current-driven insulator-to-metal phase transition (IMT). We find that the relative contribution of PE and ET effects is dictated by thermal coupling and resistivity, a discovery which disambiguates a long-standing controversy surrounding the physical nature of the current-driven IMT in vanadium oxides. Furthermore, we show that the electrothermally driven IMT occurs through a nanoscopic surface-confined filament. This nanoconfined filament has a very large thermal gradient, thus generating a large Seebeck-effect electric field.

关键词： Metal-insulator transition Thermopower Mott insulators Nanostructures Strongly correlated systems Thermoelectrics Thin films Transition metal oxides

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Perovskite Solar Cells: Enhancing Efficiency and Stability of Photovoltaic Cells by Using Perovskite/Zr-MOF Heterojunction Including Bilayer and Hybrid Structures (Adv. Sci. 5/2019)

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Advanced science 2019年第5期6卷 1970030-1970030页

作者： Chia-Chen Lee Chih-I Chen Yu-Te Liao Kevin C.-W. Wu Chu-Chen Chueh Department of Chemical Engineering National Taiwan University Taipei 10617 Taiwan Advanced Research Center for Green Materials Science and Technology National Taiwan University Taipei 10617 Taiwan Center of Atomic Initiative for New Materials (AI-MAT) National Taiwan University Taipei 10617 Taiwan International Graduate Program of Molecular Science and Technology (NTU-MST) National Taiwan University Taipei 10617 Taiwan

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Disagreement in middle ear volume estimation between tympanometry and three-dimensional volume reconstruction in the context of tympanic membrane perforation

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Journal of Otology 2017年第2期12卷 74-79页

作者： David J.Carpenter Debara L.Tucci David M.Kaylie Dennis O.Frank-Ito Division of Head and Neck Surgery&Communication Sciences Department of SurgeryDuke University Medical CenterDurhamNCUSA Computational Biology&Bioinformatics PhD Program Duke UniversityDurhamNCUSA Department of Mechanical Engineering and Materials Science Duke UniversityDurhamNCUSA

Introduction: Middle ear volume(MEV) is a clinically relevant parameter across middle ear diseases. MEV values between these techniques have never before been tested for agreement in ears with perforated tympanic membranes(TMs).Methods: Middle ears were identified from 36 patients ranging 18-89 years of age with TM perforations who underwent tympanometry and temporal bone computed tomography(CT) between 2005 and 2015. MEVs calculated by both tympanometry and three-dimensional volume reconstruction(3DVR) were analyzed for agreement using Bland Altman plots. The differences between tympanometric and 3DVR MEV values for each given middle ear were characterized across MEV quartiles(1= smallest; 4= largest) and across increasing states of middle ear disease using Kruskale Wallis and Wilcoxon testing with Bonferroni ***: Bland Altman plots demonstrated significant disagreement between MEV measurement techniques. Differences between tympanometric(T) and 3DVR MEV values were significantly greater with increasing average(i.e.(Tt3DVR)/2)) MEV per linear regression(p < 0.0001). Significance was demonstrated between fourth and first average MEV quartiles(p= 0.0024), fourth and second quartiles(p= 0.0024), third and first quartiles(p= 0.0048), and third and second quartiles(p= 0.048). Absolute MEV difference was not significantly different across varying states of middle ear disease(p= 0.44).Conclusion: Statistically and clinically significant disagreement was demonstrated between tympanometric and 3DVR MEV values. studies that vary in MEV estimation techniques may be expected to demonstrate significantly different results. These preliminary results suggest that clinicians should endeavor to seek further confirmation when interpreting high tympanometric MEV values.

关键词： Middle ear volume Tympanometry Three-dimensional volume reconstruction Tympanic membrane perforation

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Author Correction: Stretchable, dynamic covalent polymers for soft, long-lived bioresorbable electronic stimulators designed to facilitate neuromuscular regeneration

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Nature communications 2021年第1期12卷 415页

作者： Yeon Sik Choi Yuan-Yu Hsueh Jahyun Koo Quansan Yang Raudel Avila Buwei Hu Zhaoqian Xie Geumbee Lee Zheng Ning Claire Liu Yameng Xu Young Joong Lee Weikang Zhao Jun Fang Yujun Deng Seung Min Lee Abraham Vázquez-Guardado Iwona Stepien Ying Yan Joseph W Song Chad Haney Yong Suk Oh Wentai Liu Hong-Joon Yoon Anthony Banks Matthew R MacEwan Guillermo A Ameer Wilson Z Ray Yonggang Huang Tao Xie Colin K Franz Song Li John A Rogers Center for Bio-Integrated Electronics Northwestern University Evanston IL 60208 USA. Querrey Simpson Institute for Biotechnology Northwestern University Evanston IL 60208 USA. Department of Materials Science and Engineering Northwestern University Evanston IL 60208 USA. Department of Bioengineering University of California Los Angeles Los Angeles CA 90095 USA. Division of Plastic and Reconstructive Surgery Department of Surgery National Cheng Kung University Hospital College of Medicine National Cheng Kung University Tainan 70456 Taiwan. International Research Center for Wound Repair and Regeneration National Cheng Kung University Tainan 70456 Taiwan. School of Biomedical Engineering Korea University Seoul 02841 Republic of Korea. Interdisciplinary Program in Precision Public Health Korea University Seoul 02841 Republic of Korea. Department of Mechanical Engineering Northwestern University Evanston IL 60208 USA. Department of Medicine University of California Los Angeles Los Angeles CA 90095 USA. State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology 116024 Dalian China. Department of Engineering Mechanics Dalian University of Technology 116024 Dalian China. International Research Center for Computational Mechanics Dalian University of Technology 116024 Dalian China. State Key Laboratory of Chemical Engineering College of Chemical and Biological Engineering Zhejiang University 310027 Hangzhou China. Department of Biomedical Engineering Northwestern University Evanston IL 60208 USA. State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University 200240 Shanghai China. Center for Developmental Therapeutics Chemistry Life Processes Institute Northwestern University Evanston IL 60208 USA. Department of Neurological Surgery Washington University School of Medicine St. Louis MO 63110 USA. Center for Advanced Molecular Imaging Northwestern University Evanston IL

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Synthesis and Characterization of 5- and 6- Coordinated Alkali Pertechnetates

Synthesis and Characterization of 5- and 6- Coordinated Alka...

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MRS Advances

作者： Weaver, Jamie Soderquist, Chuck Gassman, Paul Walter, Eric Lukens, Wayne McCloy, John S. Department of Chemistry Washington State University PullmanWA99164 United States Pacific Northwest National Laboratory RichlandWA99352 United States Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Materials Science and Engineering Program School of Mechanical and Materials Engineering Washington State University PullmanWA99164 United States

The local chemistry of technetium-99 (99Tc) in oxide glasses is important for understanding the incorporation and long-term release of Tc from nuclear waste glasses, both those for legacy defense wastes and fuel reprocessing wastes. Tc preferably forms Tc(VII), Tc(IV), or Tc(0) in glass, depending on the level of reduction of the melt. Tc(VII) in oxide glasses is normally assumed to be isolated pertechnetate TcO4 - anions surrounded by alkali, but can occasionally precipitate as alkali pertechnetate salts such as KTcO4 and NaTcO4 when Tc concentration is high. In these cases, Tc(VII) is 4-coordinated by oxygen. A reinvestigation of the chemistry of alkali-technetium-oxides formed under oxidizing conditions and at temperatures used to prepare nuclear waste glasses showed that higher coordinated alkali Tc(VII) oxide species had been reported, including those with the TcO5 - and TcO6 - anions. The chemistry of alkali Tc(VII) and other alkali-Tc-oxides is reviewed, along with relevant synthesis conditions. Additionally, we report attempts to make 5- and 6-coordinate pertechnetate compounds of K, Na, and Li, i.e. TcO5 - and TcO6 -. It was found that higher coordinated species are very sensitive to water, and easily decompose into their respective pertechnetates. It was difficult to obtain pure compounds, but mixtures of the pertechnetate and other phase(s) were frequently found, as evidenced by x-ray absorption spectroscopy (XAS), neutron diffraction (ND), and Raman spectroscopy. Low temperature electron paramagnetic resonance (EPR) measurements showed the possibility of Tc(IV) and Tc(VI) in Na3TcO5 and Na5TcO6 compounds. It was hypothesized that the smaller counter cation would result in more stable pertechnetates. To confirm the synthesis method, LiReO4 and Li5ReO6 were prepared, and their Raman spectra match those in the literature. Subsequently, the Tc versions LiTcO4 and Li5TcO6 were synthesized and characterized by ND, Raman spectroscopy, XANES, and EXAFS. The Li5T

关键词： Neutron scattering

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A Charge-Switchable Zwitterionic Peptide for Rapid Detection of SARS-CoV-2 Main Protease

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Angewandte Chemie 2021年第9期134卷

作者： Dr. Zhicheng Jin Yash Mantri Dr. Maurice Retout Dr. Yong Cheng Dr. Jiajing Zhou Alec Jorns Dr. Pavla Fajtova Wonjun Yim Colman Moore Dr. Ming Xu Matthew N. Creyer Raina M. Borum Dr. Jingcheng Zhou Zhuohong Wu Tengyu He Prof. William F. Penny Prof. Anthony J. O'Donoghue Prof. Jesse V. Jokerst Department of NanoEngineering University of California San Diego 9500 Gilman Drive La Jolla CA 92093 USA Department of Bioengineering University of California San Diego 9500 Gilman Drive La Jolla California 92093 USA Skaggs School of Pharmacy and Pharmaceutical Sciences University of California San Diego 9500 Gilman Drive La Jolla California 92093 USA Materials Science and Engineering Program University of California San Diego 9500 Gilman Drive La Jolla California 92093 USA Department of Medicine University of California San Diego 9500 Gilman Drive La Jolla California 92093 USA Department of Radiology University of California San Diego 9500 Gilman Drive La Jolla California 92093 USA

The transmission of SARS-CoV-2 coronavirus has led to the COVID-19 pandemic. Nucleic acid testing while specific has limitations for mass surveillance. One alternative is the main protease (M pro ) due to its functional importance in mediating the viral life cycle. Here, we describe a combination of modular substrate and gold colloids to detect M pro via visual readout. The strategy involves zwitterionic peptide that carries opposite charges at the C-/N-terminus to exploit the specific recognition by M pro . Autolytic cleavage releases a positively charged moiety that assembles the nanoparticles with rapid color changes ( t <10 min). We determine a limit of detection for M pro in breath condensate matrices <10 nM. We further assayed ten COVID-negative subjects and found no false-positive result. In the light of simplicity, our test for viral protease is not limited to an equipped laboratory, but also is amenable to integrating as portable point-of-care devices including those on face-coverings.

关键词： Colorimetric analysis Covid-19 mpro/3clpro/nsp5 Smart mask Zwitterionic peptide

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Photoluminescence and terahertz time-domain spectroscopy of MBE-grown single-layered InAs/GaAs quantum dots

Photoluminescence and terahertz time-domain spectroscopy of ...

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International Conference on Infrared and Millimeter Waves

作者： Alexander E. De Los Reyes John Daniel E. Vasquez Lorenzo P. Lopez Hannah R. Bardolaza Che-Yung Chang Der-Jun Jang Armando S. Somintac Arnel A. Salvador Elmer S. Estacio National Institute of Physics University of the Philippines Diliman Quezon City Philippines Materials Science and Engineering Program University of the Philippines Diliman Quezon City Philippines University of the Philippines Diliman Quezon City Metro Manila PH Department of Physics National Sun-Yat-Sen University Kaohsiung Taiwan ROC

We study the photoluminescence (PL) and terahertz (THz) emission characteristics of MBE-grown InAs/GaAs single-layered quantum dots. Results from temperature-dependent and excitation power-dependent PL spectroscopy have revealed the presence of energy peaks corresponding to two possible quantum dot size distributions. The THz emission was found to increase as temperature increases, which we attribute to the increase in the number of carriers undergoing transport.

关键词： Spectroscopy Quantum dots Laser excitation Laser beams Temperature dependence Time-domain analysis

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The application of Bonelike® Poro as a synthetic bone substitute for the management of critical-sized bone defects - A comparative approach to the autograft technique - A preliminary study

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BONE REPORTS 2021年 14卷 101064页

作者： Pinto, P. O. Branquinho, M. V. Caseiro, A. R. Sousa, A. C. Brandao, A. Pedrosa, S. Alvites, R. D. Campos, J. M. Santos, F. L. Santos, J. D. Mendonca, C. M. Amorim, I. Atayde, L. M. Mauricio, A. C. Veterinary Clinics Department Abel Salazar Biomedical Sciences Institute (ICBAS) University of Porto (UP) Rua de Jorge Viterbo Ferreira nº 228 4050-313 Porto Portugal Animal Science Studies Centre (CECA) Agroenvironment Technologies and Sciences Institute (ICETA) University of Porto Rua D. Manuel II Apartado 55142 4051-401 Porto Portugal Vasco da Gama Research Center (CIVG) Vasco da Gama University School (EUVG) Av. José R. Sousa Fernandes 197 Campus Universitário Lordemão 3020-210 Coimbra Portugal Biosckin Molecular and Cell Therapies SA Parque de Ciência e Tecnologia da Maia Rua Eng. Frederico Ulrich 2650 4470-605 Moreira da Maia Portugal Network of Chemistry and Technology – Associated Laboratory for Green Chemistry (REQUIMTE-LAQV) Department of Metallurgy and Materials Faculty of Engineering University of Porto Rua Dr Roberto Frias s/n 4200-465 Porto Portugal Department of Pathology and Molecular Immunology Abel Salazar Institute of Biomedical Sciences (ICBAS) University of Porto (UP) Rua Jorge Viterbo Ferreira n ° 228 4050-313 Porto Portugal Institute of Research and Innovation in Health (i3S) University of Porto (UP) Rua Alfredo Allen 4200-135 Porto Portugal

The effective treatment of non-unions and critical-sized defects remains a challenge in the orthopedic field. From a tissue engineering perspective, this issue can be addressed through the application bioactive matrixes to support bone regeneration, such as Bonelike (R), as opposed to the widespread autologous grafting technique. An improved formulation of Bonelike (R) Poro, was assessed as a synthetic bone substitute in an ovine model for critical-sized bone defects. Bone regeneration was assessed after 5 months of recovery through macro and microscopic analysis of the healing features of the defect sites. Both the application of natural bone graft or Bonelike (R) Poro resulted in bridging of the defects margins. Untreated defect remained as fibrous non-unions at the end of the study period. The characteristics of the newly formed bone and its integration with the host tissue were assessed through histomorphometric and histological analysis, which demonstrated Bonelike (R) Poro to result in improved healing of the defects. The group treated with synthetic biomaterial presented bone bridges of increased thickness and bone features that more closely resembled the native spongeous and cortical bone. The application of Bonelike (R) Poro enabled the regeneration of critical-sized lesions and performed comparably to the autograph technique, validating its octeoconductive and osteointegrative potential for clinical application as a therapeutic strategy in human and veterinary orthopedics.

关键词： Bone regeneration Critical bone defects Ceramic biomaterials Bonelike (R) Ovine model

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Electrochemical-mechanically triggered transient electronics

Electrochemical-mechanically triggered transient electronics

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IEEE International Conference on Micro Electro Mechanical Systems

作者： Kyoseung Sim Xu Wang Cunjiang Yu Materials Science and Engineering Program University of Houston Houston TX USA Department of Mechanical Engineering University of Houston Houston TX USA

ISBN: (纸本)9781509050796

Electronics, which functions for a designed time period and then degrades, holds promise in lots of areas, including medical implants, disposable electronic devices and data securing hardware. Here, we report a new type of transient electronics that is triggered through electrochemical-mechanical manner with robust and reliable mechanical design, low triggering voltage and fast transient characteristics. Such device is constructed through integrating electrochemical-mechanically triggered MEMS module with functional electronics. The electrochemical-mechanical triggering mechanism in this device opens up new vistas for transient electronics designs. Various materials and different type of electronics has been demonstrated.

关键词： Transient analysis Resistors Optical imaging Etching Electrodes Optical device fabrication Logic gates

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2D Transition Metal Dichalcogenide: Unraveling High-Yield Phase-Transition Dynamics in Transition Metal Dichalcogenides on Metallic Substrates (Adv. Sci. 7/2019)

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Advanced science 2019年第7期6卷 1970042-1970042页

作者： Xinmao Yin Chi Sin Tang Di Wu Weilong Kong Changjian Li Qixing Wang Liang Cao Ming Yang Yung-Huang Chang Dianyu Qi Fangping Ouyang Stephen J. Pennycook Yuan Ping Feng Mark B. H. Breese Shi Jie Wang Wenjing Zhang Andrivo Rusydi Andrew T. S. Wee Department of Physics Faculty of Science National University of Singapore Singapore 117542 Singapore Singapore Synchrotron Light Source (SSLS) National University of Singapore Singapore 117603 Singapore NUS Graduate School for Integrative Sciences and Engineering National University of Singapore Singapore 117456 Singapore International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology Shenzhen University Shenzhen 518060 China Hunan Key Laboratory of Super-microstructure and Ultrafast Process School of Physics and Electronics Central South University No. 932 South Lushan Road Changsha Hunan Province 410083 China Department of Materials Science and Engineering National University of Singapore 9 Engineering Drive 1 Singapore 117575 Singapore Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory of the Chinese Academy of Sciences Hefei 230031 China Institute of Materials Research and Engineering A∗STAR (Agency for Science Technology and Research) 2 Fusionopolis Way Singapore 138634 Singapore Bachelor Program in Interdisciplinary Studies National Yunlin University of Science and Technology Yunlin 640 Taiwan

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