检索结果-南通市图书馆

Cardiac mechanostructure: Using mechanics and anisotropy as inspiration for developing epicardial therapies in treating myocardial infarction

在线全文

学校读者我要写书评

暂无评论

Bioactive Materials 2021年第7期6卷 2198-2220页

作者： Kiera D.Dwyer Kareen L.K.Coulombe center for biomedical engineering School of EngineeringBrown UniversityProvidenceRIUSA

The mechanical environment and anisotropic structure of the heart modulate cardiac function at the cellular,tissue and organ *** myocardial infarction(MI)and subsequent healing,however,this landscape changes *** order to engineer cardiac biomaterials with the appropriate properties to enhance function after MI,the changes in the myocardium induced by MI must be clearly *** this review,we focus on the mechanical and structural properties of the healthy and infarcted myocardium in order to gain insight about the environment in which biomaterial-based cardiac therapies are expected to perform and the functional deficiencies caused by MI that the therapy must *** this understanding,we discuss epicardial therapies for MI inspired by the mechanics and anisotropy of the heart focusing on passive devices,which feature a biomaterials approach,and active devices,which feature robotic and cellular *** this review,a detailed analysis is provided in order to inspire further development and translation of epicardial therapies for MI.

关键词： Anisotropy Cardiac biomechanics Epicardial therapies Ventricular restraint Cardiac tissue engineering

Closed-loop control of epileptiform activities in a neural population model using a proportional-derivative controller

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2015年第3期24卷 434-441页

作者：王俊松王美丽李小俚 Ernst Niebur School of biomedical engineering Tianjin Medical University Zanvyl Krieger Mind/Brain Institute and Solomon Snyder Department of neuroscience Johns Hopkins University National Key Laboratory of Cognitive neuroscience and Learning Beijing Normal University

Epilepsy is believed to be caused by a lack of balance between excitation and inhibitation in the brain. A promising strategy for the control of the disease is closed-loop brain stimulation. How to determine the stimulation control parameters for effective and safe treatment protocols remains, however, an unsolved question. To constrain the complex dynamics of the biological brain, we use a neural population model（NPM）. We propose that a proportional-derivative（PD） type closed-loop control can successfully suppress epileptiform activities. First, we determine the stability of root loci, which reveals that the dynamical mechanism underlying epilepsy in the NPM is the loss of homeostatic control caused by the lack of balance between excitation and inhibition. Then, we design a PD type closed-loop controller to stabilize the unstable NPM such that the homeostatic equilibriums are maintained; we show that epileptiform activities are successfully suppressed. A graphical approach is employed to determine the stabilizing region of the PD controller in the parameter space, providing a theoretical guideline for the selection of the PD control parameters. Furthermore, we establish the relationship between the control parameters and the model parameters in the form of stabilizing regions to help understand the mechanism of suppressing epileptiform activities in the NPM. Simulations show that the PD-type closed-loop control strategy can effectively suppress epileptiform activities in the NPM.

关键词： neural population model epileptiform activities proportional-derivative controller stabilizing region

Rat Navigation by Stimulating Somatosensory Cortex

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic engineering 2019年第5期16卷 931-942页

作者： Amirmasoud Ahmadi Mahsa Behroozi Vahid Shalchyan Mohammad Reza Daliri neuroscience&Neuroengineering Research Lab. Biomedical Engineering DepartmentSchool of Electrical EngineeringIran Univer sity of Science and Technology(IUST)Narmak16846-13114TehranIran

One of the most important topics in neuroscience is the issue ofbrain electrical stimulation and its widespread *** on this issue,rat robot,a rat navigation system,was introduced in 2002,which has utilized brain electric stimulations as a guide and a reward for driving *** systems have been designed which are automatically navigated by a *** of the obstacles in the way of these systems is to select the stimulation frequency of the somatosensory cortex for the rotation *** this paper,the stimulation parameters of the somatosensory cortex for rotation in the T-shaped maze were examined for the first time with applying only one pulse ***,the optimized parameters have been utilized in a complex *** results show that the performance is directly related to the pulse width and it has an inverse relationship with the pulse *** optimal parameters,correctly controlling the animal in 90%of the trials in the T-maze,were managed,and in the complex maze,about 70%of the stimuli with optimized parameters were with only applying one pulse *** results show that the stimulation parameters for navigation with only one pulse train are well optimized,and the results of this paper can be a trigger for an automatic navigation and reduce the computational costs and automatic system errors.

关键词： rat robot bionic robot brain computer interface electrical stimulation somatosensory cortex

Strategies for improving ductility of ordered intermetallics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2016年第1期26卷 1-12页

作者： Z.B.Jiao J.H.Luan C.T.Liu center for Advanced Structural Materials Department of Mechanical and Biomedical Engineering College of Science and Engineering City University of Hong Kong

Ordered intermetallics possess attractive high-temperature properties; however, low ductility and brittle fracture limit their use as engineering materials in many cases. This paper provides a comprehensive review on the recent progress in the development of ductile ordered intermetallics and summarizes the strategies used to improve the tensile ductility of ordered intermetallics, including control of ordered crystal structures,engineering grain-boundary structure and chemistry, eliminating environmental embrittlement, microstructure optimization, control of phase stability, and promoting transformation-/twining-induced plasticity. The basic ideas and related mechanisms underlying these ductilizing strategies are discussed. In addition, a brief mention of the current use of intermetallic alloys for structural and corrosion applications is made.

关键词： Ordered intermetallics Ductility Ductilizing strategy Microstructure Alloy design

Terpyridine-Grafted Nitrogen-Terminal Endowing Cyanine with Metal-Ion-Regulated Photophysical Properties for Cancer Theranostics

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research 2023年第4期2023卷 117-130页

作者： Junfei Zhu Gang He Peng-Hang Chen Yajie Zhang Yafei Zhang Shan Lei Yu Zhang Meng Li Peng Huang Jing Lin Marshall Laboratory of biomedical engineering International Cancer CenterLaboratory of Evolutionary Theranostics(LET)Guangdong Key Laboratory for Biomedical Measurements and Ultrasound ImagingSchool of Biomedical EngineeringShenzhen University Medical SchoolShenzhen 518060China

Heptamethine cyanines(Cy7)are one of the most important dyes in bioimaging and phototherapy,but they often suffer from poor photostability or limited photothermal conversion ***,a facile molecular engineering approach to regulating the photophysical properties of Cy7 by metal ions is *** innovatively modifying the nitrogen with functional groups,a novel terpyridine-grafted nitrogen-terminated Cy7 scaffold(denoted as CydtPy)was synthesized and exhibited tunable photophysical properties when chelating with various metal ions(Mn^(2+),Fe^(2+),etc.).In comparison with metal-ion-free PEGylated CydtPy(LET-11),Mn^(2+)-chelated LET-11(namely,LET-11-Mn)exhibited the increased fluorescence emission intensity,and Fe^(2+)-chelated LET-11(namely,LET-11-Fe)showed the enhanced photostability with~2-fold increase in photothermal conversion *** simply switching the chelated metal ion species,LET-11-Mn or LET-11-Fe could be used for near-infrared fluorescence imaging,magnetic resonance imaging,or photoacoustic ***,LET-11-Fe displayed superior synergistic efficacy of photothermal therapy and chemodynamic therapy both in vitro and in *** work not only provides a new strategy for regulating the photophysical properties of cyanine dyes but also establishes a versatile nanoplatform for cancer theranostics.

关键词： versatile terminated cyanine

Mild hyperthermia-enhanced chemo-photothermal synergistic therapy using doxorubicin-loaded gold nanovesicles

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第8期32卷 2411-2414页

作者： Zhuoting Deng Chao Jiang Muhammad Rizwan Younis Shan Lei Yaling He Haoxing Zheng Peng Huang Jing Lin Marshall Laboratory of biomedical engineering International Cancer CenterLaboratory of Evolutionary Theranostics(LET)School of Biomedical EngineeringShenzhen University Health Science CenterShenzhen 518060China

Gold nanovesicles(GVs) with unique plasmonic property and large cavity hold great potential as a stimuli-responsive nanocarrier to deliver drugs for efficient tumor chemotherapy and other therapies ***,we developed doxorubicin-loaded gold nanovesicles(DGVs),offering infrared thermal(IRT) and photoacoustic(PA) dual-modal imaging guided mild hype rthermia-enhanced chemophotothermal cancer synergistic *** DGVs are self-assembled by gold nanoparticles modified with amphiphilic copolymer in a predetermined concentration of doxorubicin through film rehydration *** the influence of laser excitation,the as-prepared DGVs exhibited good photothermal effect,which triggered the structural disruption of GVs and thus,allowed the efficient release of encapsulated DOX to enhance cell uptake for fluorescence imaging and tumor chemotherapy,*** addition,DGVs also showed a strong PA and IRT signals in *** study demonstrated the potential of DGVs as stimuli-responsive drug delivery systems and cancer theranostics.

关键词： Mild hyperthermia Chemo-photothermal synergistic therapy Gold nanovesicles Doxorubicin Photoacoustic imaging

Electric-stimulus rate encoding algorithm of Mandarin tonal information in cochlear implant

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第12期16卷 1315-1321页

作者： GUAN Tian~1, GONG Qin~1 and YE Datian~2**(1. Department of biomedical engineering, Tsinghua University, Beijing 100084, China 2. Research center of biomedical engineering, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China) [a]Department of biomedical engineering Tsinghua University Beijing China [b]Research center of biomedical engineering Graduate School at Shenzhen Tsinghua University Shenzhen China

The modern multi-channel cochlear implants usually extract and encode the temporal envelope cues. This kind of algorithms can hardly satisfy the users who speak tonal languages, such as Mandarin. Many studies have tried to enhance the recognition ability of Mandarin through encoding tonal information and made suggestions to frequency-modulate the fixed pulse-rate carrier with the extracted tonal information based on the rate-pitch theory in electric hearing. However, how to encode and deliver the tonal information such as F_0by changing electric-stimulus rate has not got further study in clinical electric-stimulus mode. The present paper focuses on this matter by piecewise calculating the appreciable electric-stimulus rates. Then an electric-stimulus encoding algorithm of Mandarin tone is brought forward and testified through acoustic simulations. Such conclusion can be drawn that this algorithm of electric-stimulus rate could convey tonal information well and help to enhance the Mandarin speech recognition ability.

关键词： cochlear implant tone fundamental frequency electric-stimulus rate.

Recent advances in fluorescence imaging of alkaline phosphatase

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第4期32卷 1316-1330页

作者： Meng Li Bhaskar Gurram Shan Lei Nicholas TBlum Peng Huang Jing Lin Marshall Laboratory of biomedical engineering.International Cancer center Laboratory of Evolutionary Theranostics(LET)School of Biomedical Engineering.Shenzhen University Health Science CenterShenzhen 518060China

Phosphatase plays a vital important role in many biological functions due to the dephosphorylation serves varied roles in cellular regulation and *** the family of phosphatase,alkaline phosphatase(ALP)could act as crucial prognostic indicators for many diseases such as bone diseases and ***,the detection of ALP is mainly limited to in vitro colorimetric method in ***,huge efforts have been paid on the fluorescence imaging that provides a reliable method to detect the real-time and in vivo changes of the level of *** this review,we summarize recent advances in fluorescence imaging of phosphatase,mainly focused on *** imaging probes of phosphatase are mainly classified according to their luminescence *** the end,we assessed the challenges and future prospects of phosphatase probes.

关键词： Alkaline phosphatase Acid phosphatase Fluorescence imaging Luminescence mechanism

Parallel variable-density spiral imaging using nonlocal total variation reconstruction

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第5期23卷 530-536页

作者：方晟郭华 Institute of Nulcear and New Energy Technology Tsinghua University center for biomedical Imaging Research Department of Biomedical EngineeringSchool of MedicineTsinghua University

The relatively long scan time is still a bottleneck for both clinical applications and research of magnetic resonance imaging. To reduce the data acquisition time, we propose a novel fast magnetic resonance imaging method based on parallel variable-density spiral acquisition, which combines undersampling optimization and nonlocal total variation reconstruction. The undersampling optimization promotes the incoherence of resultant aliasing artifact via the ＂worst-case＂ residual error metric, and thus accelerates the data acquisition. Moreover, nonlocal total variation reconstruction is utilized to remove such an incoherent aliasing artifact and so improve image quality. The feasibility of the proposed method is demonstrated by both numerical phantom simulation and in vivo experiment. The experimental results show that the proposed method can achieve high acceleration factor and effectively remove an aliasing artifact from data undersampling with well-preserved image details. The image quality is better than that achieved with the total variation method.

关键词： magnetic resonance imaging variable-density spiral parallel imaging nonlocal total variation