检索结果-内蒙古大学图书馆

arXiv 2020年

作者： Liu, Xiaolong Wang, Luqing Yakobson, Boris I. Hersam, Mark C. Applied Physics Graduate Program Northwestern University EvanstonIL60208 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Department of Chemistry Rice University HoustonTX77005 United States Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States Department of Electrical and Computer Engineering Northwestern University EvanstonIL60208 United States

Using field-emission resonance spectroscopy with an ultrahigh vacuum scanning tunneling microscope, we reveal Stark-shifted image-potential states of the v1/6 and v1/5 borophene polymorphs on Ag(111) with long lifetimes, suggesting high borophene lattice and interface quality. These image-potential states allow the local work function and interfacial charge transfer of borophene to be probed at the nanoscale and test the widely employed self-doping model of borophene. Supported by apparent barrier height measurements and density functional theory calculations, electron transfer doping occurs for both borophene phases from the Ag(111) substrate. In contradiction with the self-doping model, a higher electron transfer doping level occurs for denser v1/6 borophene compared to v1/5 borophene, thus revealing the importance of substrate effects on borophene electron transfer. Copyright © 2020, The Authors. All rights reserved.

关键词： Electron transitions

来源：评论

学校读者我要写书评

暂无评论

Hydrogel Network Dynamics Regulate Vascular Morphogenesis

SSRN

引用

SSRN 2020年

作者： Wei, Zhao Schnellmann, Rahel Gerecht, Sharon Department of Chemical and Biomolecular Engineering The Institute for NanoBioTechnology Physical Sciences-Oncology Center Johns Hopkins University BaltimoreMD21218 United States Department of Materials Science and Engineering Johns Hopkins University BaltimoreMD21218 United States Department of Biomedical Engineering Johns Hopkins University School of Medicine BaltimoreMD21205 United States Department of Oncology Johns Hopkins University School of Medicine BaltimoreMD21205 United States

Increasingly, matrix dynamics is being recognized as an indispensable characteristic impacting single cell behavior and fate. However, it is unknown how matrix dynamics influence individual cells to ultimately make up a complex multicellular tissue, such as vascular networks. Here we develop hydrogels with identical polymer components but different cross-links, enabling to investigate how matrix dynamics modulate vascular morphogenesis. We show that the dynamics of hydrogel networks alone, independent of stiffness, promote clustering of integrin β1 and the recruitment of vinculin, leading to the formation of focal adhesions and the phosphorylation of the focal adhesion kinase (FAK). We further demonstrate that dynamic-mediated FAK activation leads to an upregulation in metalloproteinases (MMP) expression, enabling rapid sprouting and robust assembly of vasculature. These results emphasize the importance of matrix dynamics in vascular tissue formation and the corresponding molecular pathways, which have implications for mechanistic studies and applications for tissue engineering and vascularization. © 2020, The Authors. All rights reserved.

关键词： Stiffness

来源：评论

学校读者我要写书评

暂无评论

A ggregation-induced emission nanoparticles for in vivo three-photon fuorescence microscopic rat brain angiography

引用

Journal of Innovative Optical Health sciences 2019年第6期12卷 34-45页

作者： Hequn Zhang Weisi Xie Ming Chen Liang Zhu Zhe Feng Yalun Wang Wang Xi Ben Zhong Tang Jun Qian Centre for Optical and Electromagnetic Research Zhejiang University Hangzhou 310058P.R.China Department of Chemistry Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction Division of Life Science State Key Laboratory of Molecular Neuroscience Institute for Advanced StudyInstitute of Molecular Functional Materials Division of Biomedical Engineering The Hong Kong University of Science and Technology Clear Water BayKowloonHong KongP.R.China Interdisciplinary Institute of Neuroscience and Technology(ZIINT)Zhejiang University Hangzhou310058P.R.China

Rodents are popular biological models for physiological and behavioral research in neuroscience and rats are better models than mice due to their higher genome similarity to human and more accessible surgical ***,rat brain is larger than mice brain and it needs powerful imaging tools to implement better penetration against the scattering of the thicker brain ***-photon fluorescence microscopy(3PFM)combined with near-infrared(NIR)excitation has great potentials for brain circuits imaging beause of its abilities of anti scattering,deep-tissue imaging,and high signal-to-noise ratio(SNR).In this work,a type of AIE lumninogen with red fuorescence was synthesized and encapsulated with Pluronic F-127 to make up form nano-particles(NPs).Bright DCDPP-2TPA NPs were employed for in trino three-photon fuorescent laser scanning microscopy of blood vessels in rats brain under 1550 nm femtosecond laser exci-tation.A fine three-dimensional(3D)reconstruction up to the deepness of 600 pm was achieved and the blood flow velocity of a selected vessel was measured in vrito as *** 3PFM deep brain imaging method simultaneously recorded the morphology and function of the brain blood vessels in vivo in the rat *** this angiography combined with the arsenal of rodent's brain disease,models can accelerate the neuroscience research and clinical diagnosis of brain disease in the future.

关键词： Three photon fluorescence microscopy(3PFM) aggregation induced emision(AIE) deep-tissue imaging in vivo rat brain

来源：评论

学校读者我要写书评

暂无评论

Thermal and electrical properties of hybrid composites with graphene and boron nitride fillers

arXiv

引用

arXiv 2019年

作者： Lewis, Jacob S. Barani, Zahra Magana, Andres Sanchez Kargar, Fariborz Balandin, Alexander A. Center Department of Electrical and Computer Engineering Materials Science and Engineering Program Bourns College of Engineering University of California RiversideCA92521 United States

We report on the thermal and electrical properties of hybrid epoxy composites with graphene and boron nitride fillers. The thicknesses, lateral dimensions, and aspect ratios of each filler material were intentionally selected for geometric similarity to one another, in contrast to prior studies that utilized dissimilar filler geometries to achieve a "synergistic" effect. We demonstrate that the electrically-conductive graphene and electrically-insulating boron nitride fillers allow one to effectively engineer the thermal and electrical conductivities of their resulting composites. By varying the constituent fraction of boron nitride to graphene in a composite with ~44% total filler loading, one can tune the thermal conductivity enhancement from a factor of ×15 to ×35 and increase the electrical conductivity by many orders of magnitude. The obtained results are important for the development of next-generation thermal interface materials with controllable electrical properties necessary for applications requiring either electrical grounding or insulation. Copyright © 2019, The Authors. All rights reserved.

关键词： Aspect ratio

来源：评论

学校读者我要写书评

暂无评论

In vivo photothermal reconfiguration of liquid crystalline elastomer nanocomposites

引用

Cell biomaterials 2025年第2期1卷 100022页

作者： Nathaniel P Skillin Bruce E Kirkpatrick Nicole E Friend Amy R Perry Joselle M McCracken Melvin Colorado Escobar Benjamin R Nelson Nathaniel L Day Patrick S Hume Taufiek Konrad Rajab Kristi S Anseth Timothy J White Department of Chemical and Biological Engineering University of Colorado Boulder Boulder CO 80303 USA. The BioFrontiers Institute University of Colorado Boulder Boulder CO 80303 USA. Medical Scientist Training Program School of Medicine University of Colorado Anschutz Medical Campus Aurora CO 80045 USA. Department of Molecular Cellular and Developmental Biology University of Colorado Boulder Boulder CO 80303 USA. Materials Science and Engineering Program University of Colorado Boulder Boulder CO 80303 USA. Department of Medicine National Jewish Health Denver CO 80206 USA. Department of Cardiovascular Surgery Arkansas Children's Hospital Little Rock AR 72202 USA. Lead contact.

Medical implants with fixed geometry have many clinical applications but are limited by the dynamic nature of human physiology. To overcome this barrier, focus has shifted to stimuli-responsive materials capable of changing their geometry on demand, such as liquid crystalline elastomers (LCEs). Here, we report on the development and biological performance of LCE-gold nanorod (LCE-AuNR) nanocomposites engineered for use in optically reconfigurable medical devices. First, we maximized the strain response and force output of 3D-printed LCE-AuNR within a physiologically relevant temperature window of 37°C-50°C. LCE-AuNR are shown to be cytocompatible and induce a comparable foreign body response to medical grade silicone when implanted subcutaneously in mice. Upon transcutaneous near-infrared irradiation, implanted LCE-AuNR exhibit rapid and reversible photothermal actuation. Furthermore, controlled photothermal actuation does not result in the pathology of adjacent tissues. This approach opens new horizons for designing dynamic medical implants across a wide range of clinical applications.

关键词： liquid crystalline elastomer gold nanorod photothermal foreign body response adjustable medical device transcutaneous stimulation

来源：评论

学校读者我要写书评

暂无评论

Integrating material properties from magnetic resonance elastography into subject-specific computational models for the human brain

引用

Brain Multiphysics 2021年 2卷 100038页

作者： Alshareef, Ahmed Knutsen, Andrew K. Johnson, Curtis L. Carass, Aaron Upadhyay, Kshitiz Bayly, Philip V. Pham, Dzung L. Prince, Jerry L. Ramesh, K.T. Department of Electrical and Computer Engineering Johns Hopkins University 3400 N Charles St. Baltimore 21218 MD United States Department of Mechanical Engineering Johns Hopkins University 3400 N Charles St. Baltimore 21218 MD United States Center for Neuroscience and Regenerative Medicine Henry M. Jackson Foundation 6720A Rockledge Dr Bethesda 20814 MD United States Department of Biomedical Engineering University of Delaware 210 South College Ave. Newark 19716 DE United States Mechanical Engineering and Materials Science Washington University in St. Louis 1 Brookings Drive St. Louis 63130 MO United States

Advances in brain imaging and computational methods have facilitated the creation of subject-specific computational brain models that aid researchers in investigating brain trauma using simulated impacts. The emergence of magnetic resonance elastography (MRE) as a non-invasive mechanical neuroimaging tool has enabled in vivo estimation of material properties at low-strain, harmonic loading. An open question in the field has been how this data can be integrated into computational models. The goals of this study were to use a novel MRI dataset acquired in human volunteers to generate models with subject-specific anatomy and material properties, and then to compare simulated brain deformations to subject-specific brain deformation data under non-injurious loading. Models of five subjects were simulated with linear viscoelastic (LVE) material properties estimated directly from MRE data. Model predictions were compared to experimental brain deformation acquired in the same subjects using tagged MRI. Outcomes from the models matched the spatial distribution and magnitude of the measured peak strain components as well as the 95^th percentile in-plane peak strains within 0.005 mm/mm and maximum principal strain within 0.012 mm/mm. Sensitivity to material heterogeneity was also investigated. Simulated brain deformations from a model with homogenous brain properties and a model with brain properties discretized with up to ten regions were very similar (a mean absolute difference less than 0.0015 mm/mm in peak strains). Incorporating material properties directly from MRE into a biofidelic subject-specific model is an important step toward future investigations of higher-order model features and simulations under more severe loading conditions. Statement of Significance: The study presents a method to calibrate and evaluate subject-specific finite element brain models using a combination of advanced magnetic resonance imaging (MRI) data. The imaging data is acquired i

关键词： Brain deformation Magnetic resonance elastography Magnetic resonance imaging Model evaluation Subject-specific models

来源：评论

学校读者我要写书评

暂无评论

Extraction of isotropic electron-nuclear gyperfine coupling constants of paramagnetic point defects from near-zero field magnetoresistance spectra via least squares fitting to models developed from the stochastic quantum liouville equation

arXiv

引用

arXiv 2020年

作者： Frantz, Elias B. Harmon, Nicholas J. McMillan, Stephen R. Moxim, Stephen J. Flatté, Michael E. Lenahan, Patrick M. Intercollege Graduate Degree Program in Materials Science and Engineering Pennsylvania State University University ParkPA16802 United States Department of Physics University of Evansville EvansvilleIN47722 United States Department of Physics and Astronomy University of Iowa Iowa CityIA52242 United States Department of Engineering Science and Mechanics Pennsylvania State University University ParkPA16802 United States

We report on a method by which we can systematically extract spectroscopic information such as isotropic electron-nuclear hyperfine coupling constants from near-zero field magnetoresistance (NZFMR) spectra. The method utilizes a least squares fitting of models developed from the stochastic quantum Liouville equation. We applied our fitting algorithm to two distinct material systems: Si/SiO2 metal oxide field effect transistors (MOSFETs), and a-Si:H metal insulator semiconductor (MIS) capacitors. Our fitted results and hyperfine parameters are in reasonable agreement with existing knowledge of the defects present in the systems. Our work indicates that the NZFMR response and fitting of the NZFMR spectrum via models developed from the stochastic quantum Liouville equation could be a relatively simple yet powerful addition to the family of spin-based techniques used to explore the chemical and structural nature of point defects in semiconductor devices and insulators. Copyright © 2020, The Authors. All rights reserved.

关键词： Point defects

来源：评论

学校读者我要写书评

暂无评论

6 nm super-resolution optical transmission and scattering spectroscopic imaging of carbon nanotubes using a nanometer-scale white light source

arXiv

引用

arXiv 2020年

作者： Ma, Xuezhi Liu, Qiushi Yu, Ning Xu, Da Kim, Sanggon Liu, Zebin Jiang, Kaili Wong, Bryan Yan, Ruoxue Liu, Ming Department of Electrical and Computer Engineering University of California - Riverside RiversideCA92521 United States Department of Chemical and Environmental Engineering University of California - Riverside RiversideCA92521 United States State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China Materials Science and Engineering program University of California - Riverside RiversideCA92521 United States

Optical transmission and scattering spectroscopic microscopy at the visible and adjacent wavelengths denote one of the most informative and inclusive characterization methods in material research. Unfortunately, restricted by the diffraction limit of light, it cannot resolve the nanoscale variation in light absorption and scattering, diagnostics of the local inhomogeneity in material structure and properties. Moreover, a large quantity of nanomaterials has anisotropic optical properties that are appealing yet hard to characterize through conventional optical methods. There is an increasing demand to extend the optical hyperspectral imaging into the nanometer length scale. In this work, we report a super-resolution hyperspectral imaging technique that uses a nanoscale white light source generated by superfocusing the light from a tungsten-halogen lamp to simultaneously obtain optical transmission and scattering spectroscopic images. A 6-nm spatial resolution in the visible to near-infrared wavelength regime (415 - 980 nm) is demonstrated on an individual single-walled carbon nanotube (SW-CNT). Both the longitudinal and transverse optical electronic transitions are measured, and the SW-CNT chiral indices can be identified. The band structure modulation in a SW-CNT through strain engineering is mapped. Copyright © 2020, The Authors. All rights reserved.

关键词： Optical resolving power

来源：评论

学校读者我要写书评

暂无评论

Selective CO2Reduction to Ethylene Mediated by Adaptive Small-molecule engineering of Copper-based Electrocatalysts

引用

Angewandte Chemie 2023年第50期135卷

作者： Dr. Shenghua Chen Dr. Chengliang Ye Dr. Ziwei Wang Dr. Peng Li Dr. Wenjun Jiang Dr. Zechao Zhuang Dr. Jiexin Zhu Dr. Xiaobo Zheng Dr. Shahid Zaman Dr. Honghui Ou Lei Lv Dr. Lin Tan Dr. Yaqiong Su Dr. Jiang Ouyang Prof. Dingsheng Wang National Innovation Platform (Center) for Industry-Education Integration of Energy Storage Technology School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an 710049 P. R. China Engineering Research Center of Advanced Rare Earth Materials Department of Chemistry Tsinghua University Beijing 100084 P. R. China School of Chemistry Xi'an Key Laboratory of Sustainable Energy Materials Chemistry State Key Laboratory of Electrical Insulation and Power Equipment Engineering Research Center of Energy Storage Materials and Devices Ministry of Education Xi'an Jiaotong University Xi'an 710049 P. R. China Qian Xuesen Laboratory of Space Technology China Academy of Space Technology Beijing 100094 P. R. China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 P. R China Key Laboratory of Energy Conversion and Storage Technologies Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen 518055 P. R. China School of Biomedical Engineering Guangzhou Medical University Guangzhou 511436 P. R. China

Electrochemical CO 2 reduction reaction (CO 2 RR) over Cu catalysts exhibits enormous potential for efficiently converting CO 2 to ethylene (C 2 H 4 ). However, achieving high C 2 H 4 selectivity remains a considerable challenge due to the propensity of Cu catalysts to undergo structural reconstruction during CO 2 RR. Herein, we report an in situ molecule modification strategy that involves tannic acid (TA) molecules adaptive regulating the reconstruction of a Cu-based material to a pathway that facilitates CO 2 reduction to C 2 H 4 products. An excellent Faraday efficiency (FE) of 63.6 % on C 2 H 4 with a current density of 497.2 mA cm −2 in flow cell was achieved, about 6.5 times higher than the pristine Cu catalyst which mainly produce CH 4 . The in situ X-ray absorption spectroscopy and Raman studies reveal that the hydroxyl group in TA stabilizes Cu δ+ during the CO 2 RR. Furthermore, theoretical calculations demonstrate that the Cu δ+ /Cu 0 interfaces lower the activation energy barrier for *CO dimerization, and hydroxyl species stabilize the *COH intermediate via hydrogen bonding, thereby promoting C 2 H 4 production. Such molecule engineering modulated electronic structure provides a promising strategy to achieve highly selective CO 2 reduction to value-added chemicals.

关键词： C2H4 CO2RR Cuδ+/Cu0 Hydrogen Bonding TA Molecule

来源：评论

学校读者我要写书评

暂无评论

Finite element analysis of posterior leaf spring ankle-foot orthosis for tibialis anterior atrophy case

引用

AIP Conference Proceedings 2022年第1期2663卷

作者： Alfian Pramudita Putra Arief Sofian Hidayat Akif Rahmatillah Pujiyanto Pujiyanto Dinda Cyberputri I. Putu Alit Pawana 1Biomedical Engineering Study Program Department of Physics Faculty of Science and Technology Universitas Airlangga Surabaya Indonesia 2Biomedical Signals and Systems Research Group Faculty of Science and Technology Universitas Airlangga Surabaya Indonesia 3Department of Physics Faculty of Science and Technology Universitas Airlangga Surabaya Indonesia 4Department of Rehabilitation and Physical Medicine Dr. Soetomo General Academic Hospital Surabaya Indonesia

Stroke is a neurological disease and is a significant cause of disability throughout the world. Patients with stroke or post-stroke usually still experience interference in walking in the form of a drop foot caused by atrophy of the anterior tibialis muscle, so they cannot perform dorsiflexion. Drop foot disorders can be treated by rehabilitation using Posterior Leaf Spring Ankle-Foot Orthosis (PLS AFO). PLS AFO has the advantage of a higher level of flexibility compared to other AFO types. The primary purpose of this research is to observe the level of resilience based on the influence of AFO thickness. This study uses the finite element analysis of three model variations in the initial contact, midstance, terminal stance, and calf loading phases. The material used in this study was carbon fiber. The simulation will result in the distribution of stress, strain, and deformation values in each AFO model. The simulation results show that AFO resistance is affected by variations in AFO thickness where the increase in strength is proportional to the increase in AFO thickness. The AFO with a thickness of 10 mm is the most suitable for the tibialis anterior atrophy case.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：