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Tsinghua Science and Technology 2020年第3期25卷 435-446页

作者： Shangen Zhang Xu Han Xiaorong Gao the Department of biomedical Engineering School of Medicine Tsinghua University

This study explored methods for improving the performance of Steady-State Visual Evoked Potential(SSVEP)-based Brain-Computer Interfaces(BCI), and introduced a new analytical method to quantitatively analyze and reflect the characteristics of SSVEP. We focused on the effect of the pre-stimulation paradigm on the SSVEP dynamic models and the dynamic response process of SSVEP, and performed a comparative analysis of three pre-stimulus paradigms(black, gray, and white). Four dynamic models with different orders(second-and third-order)and with and without a zero point were used to fit the SSVEP envelope. The zero-pole analytical method was adopted to conduct quantitative analysis on the dynamic models, and the response characteristics of SSVEP were represented by zero-pole distribution characteristics. The results of this study indicated that the pre-stimulation paradigm affects the characteristics of SSVEP, and the dynamic models had good fitting abilities with SSVEPs under various types of pre-stimulation. Furthermore, the zero-pole characteristics of the models effectively characterize the damping coefficient, oscillation period, and other SSVEP characteristics. The comparison of zeros and poles indicated that the gray pre-stimulation condition corresponds to a lower damping coefficient, thus showing its potential to improve the performance of SSVEP-BCIs.

关键词： Steady-State Visual Evoked Potential(SSVEP) dynamic model pre-stimulation zero and pole analysis brain-computer interface

A molecular arms race between host innate antiviral response and emerging human coronaviruses

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Virologica Sinica 2016年第1期31卷 12-23页

作者： Lok-Yin Roy Wong Pak-Yin Lui Dong-Yan Jin school of biomedical Sciences The University of Hong Kong

Coronaviruses have been closely related with mankind for thousands of years. Communityacquired human coronaviruses have long been recognized to cause common cold. However,zoonotic coronaviruses are now becoming more a global concern with the discovery of highly pathogenic severe acute respiratory syndrome(SARS) and Middle East respiratory syndrome(MERS) coronaviruses causing severe respiratory diseases. Infections by these emerging human coronaviruses are characterized by less robust interferon production. Treatment of patients with recombinant interferon regimen promises beneficial outcomes, suggesting that compromised interferon expression might contribute at least partially to the severity of disease. The mechanisms by which coronaviruses evade host innate antiviral response are under intense investigations. This review focuses on the fierce arms race between host innate antiviral immunity and emerging human coronaviruses. Particularly, the host pathogen recognition receptors and the signal transduction pathways to mount an effective antiviral response against SARS and MERS coronavirus infection are discussed. On the other hand, the counter-measures evolved by SARS and MERS coronaviruses to circumvent host defense are also dissected. With a better understanding of the dynamic interaction between host and coronaviruses, it is hoped that insights on the pathogenesis of newly-identified highly pathogenic human coronaviruses and new strategies in antiviral development can be derived.

关键词： MERS-CoV SARS-CoV innate antiviral response type I interferons immune evasion

In-vivo fluorescence molecular tomography based on optimal small animal surface reconstruction

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Chinese Optics Letters 2010年第1期8卷 82-85页

作者：汪待发刘欣陈延平白净 Department of biomedical Engineering School of MedicineTsinghua University

Accurate small animal surface reconstruction is important for full angle non-contact fluorescence molecular tomography （FMT） systems. In this letter, an optimal surface reconstruction method for FMT is proposed. The proposed method uses a line search method to minimize the mismatch between the reconstructed three- dimensional （3D） surface and the projected object silhouette at different angles. The results show that the mean mismatches of the 3D surfaces generated on three live anesthetized mice are all less than two charge coupled device （CCD） pixels （0.154 mm）. With the accurately reconstructed 3D surface, in-vivo FMT is also performed.

关键词： Animals Charge coupled devices Digital cameras Fluorescence Hearing aids Pulse modulation Repair Three dimensional Tomography

In vivo whole-body imaging of optical agent dynamics using full angle fluorescence diffuse optical tomography

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Chinese Optics Letters 2010年第12期8卷 1156-1159页

作者：刘欣刘飞汪待发白净 Department of biomedical Engineering School of MedicineTsinghua University

Dynamic fluorescence diffuse optical tomography （FDOT） is important in drug deliver research. In this letter, we first image the metabolic processes of micelles indocyanine green throughout the whole body of a nude mouse using the full-angle FDOT system with line illumination （L-FDOT）. The resolution of L-FDOT is evaluated using phantom experiment. Next, in vivo dynamic tomographic images （100 frames; approximately 170 min） of mouse liver and abdomen are shown and cross-validated by planar fluorescence reflectance imaging in vitro. Results provide evidence on applicability of the tomographic image wholebody biological activities in vivo on minute timescale （approximately 1.7 min） using L-FDOT.

关键词： Optical tomography

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

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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

Amyotrophic lateral sclerosis as a synaptopathy

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Neural Regeneration Research 2019年第2期14卷 189-192页

作者： Matthew J.Fogarty Department of Physiology and biomedical Engineering Mayo Clinic school of biomedical Sciences The University of Queensland

The synapse is an incredibly specialized structure that allows for the coordinated communication of information from one neuron to another. When assembled into circuits, steady streams of excitatory and inhibitory synaptic activity shape neural outputs. At the organismal level, ensembles of neural networks underlie behavior, emotion and memory. Disorder or dysfunctions of synapses, a synaptopathy, may underlie a host of developmental and degenerative neurological conditions. There is a possibility that amyotrophic lateral sclerosis may be a result of a synaptopathy within the neuromotor system. To this end, particular attention has been trained on the excitatory glutamatergic synapses and their morphological proxy, the dendritic spine. The extensive detailing of these dysfunctions in vulnerable neuronal populations, including corticospinal neurons and motor neurons, has recently been the subject of original research in rodents and humans. If amyotrophic lateral sclerosis is indeed a synaptopathy, it is entirely consistent with other proposed pathogenic mechanisms – including glutamate excitotoxicity, accumulation of misfolded proteins and mitochondrial dysfunction at distal axon terminals(cortico-motor neuron and neuromuscular). Further, although the exact mechanism of disease spread from region to region is unknown, the synaptopathy hypothesis is consistent with emerging die-forward evidence and the prion-like propagation of misfolded protein aggregates to distant neuronal populations. Here in this mini-review, we focus on the timeline of synaptic observations in both cortical and spinal neurons from different rodent models, and provide a conceptual framework for assessing the synaptopathy hypothesis in amyotrophic lateral sclerosis.

关键词： motor neuron motor cortex corticospinal excitotoxicity synaptic transmission dendrites dendriticspines neuromuscular junction

Stimulus discrimination via responses of retinal ganglion cells and dopamine-dependent modulation

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Neuroscience Bulletin 2013年第5期29卷 621-632页

作者： Hao Li Pei-Ji Liang school of biomedical Engineering Shanghai Jiao Tong University

Neighboring retinal ganglion cells（RGCs）fire with a high degree of *** has been increasingly realized that visual perception of the environment relies on neuronal population activity to encode and transmit the information contained in *** how neuronal population activity contributes to visual information processing is essential for understanding the mechanisms of visual *** we simultaneously recorded spike discharges from groups of RGCs in bullfrog retina in response to visual patterns（checkerboard,horizontal grating,and full-field illumination）using a multi-electrode array *** determine the role of synchronous activity mediated by gap junctions,we measured the correct classification rates of single cells＇firing patterns as well as the synchronization patterns of multiple *** found that,under normal conditions,RGC population activity exhibited distinct response features with exposure to different stimulus patterns and had a higher rate of correct stimulus discrimination than the activity of single ***（1μmol/L）application did not significantly change the performance of single neuron activity,but enhanced the synchronization of the RGC population activity and decreased the rate of correct stimulus pattern *** findings suggest that the synchronous activity of RGCs plays an important role in the information coding of different types of visual patterns,and a dopamine-induced increase in synchronous activity weakens the population performance in pattern discrimination,indicating the potential role of the dopaminergic pathway in modulating the population coding process.

关键词： retinal ganglion cells synchronous activity dopamine information coding

A Concise Review of Gold Nanoparticles-Based Photo-Responsive Liposomes for Controlled Drug Delivery

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Nano-Micro Letters 2018年第1期10卷 85-94页

作者： Malathi Mathiyazhakan Christian Wiraja Chenjie Xu school of Chemical and biomedical Engineering Nanyang Technological University

The focus of drug delivery is shifting toward smart drug carriers that release the cargo in response to a change in the microenvironment due to an internal or external trigger. As the most clinically successful nanosystem, liposomes naturally come under the spotlight of this trend. This review summarizes the latest development about the design and construction of photo-responsive liposomes with gold nanoparticles for the controlled drug release. Alongside, we overview the mechanism involved in this process and the representative applications.

关键词： Photo-responsive liposome Controlled release Drug delivery Gold nanoparticles

Flow behavior and deposition study of pollen-shape carrier particles in an idealized inhalation path model

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Particuology 2010年第1期8卷 51-59页

作者： Meer Saiful Hassan Raymond Lau school of Chemical and biomedical Engineering (SCBE) Nanyang Technological University (NTU)

Pollen-shape （spiked sphere） hydroxyapatite （HA） particles for drug carrier application are studied. The particle shape and size effect on flow characteristics and deposition are assessed. The pollen-shape HA particles are synthesized to have comparable size as typical carrier particles with mean diameter of 30-50 μm and effective density less than 0.3 g/cm^3. The flow behaviors of HA and commonly used lactose （LA） carrier particles are characterized by the Carr＇s compressibility index （CI）. The HA particles have lower CI than the LA particles for the same size range. The flow fields of HA and LA carrier particles are measured in an idealized inhalation path model using particle image velocimetry （PLY） technique. The particle streamlines indicate that a large portion of particles may deposit at the bending section due to inertial impaction and gravitational deposition. The flow field result shows that HA particles give smaller separation regions than the LA particles for the same size range. The pollen-shape HA particles are found to be able to follow the gas flow in the model and minimize undesired deposition. Deposition result confirms the bending section to have the most deposition. Deposition is found to be a function of particle properties. An empirical correlation is derived for the deposition efficiency of the pollen-shape particles as a function of particles Stokes number.

关键词： Aerosol Fluid mechanics Multiphase flow Particle Powder technology Pulmonary drug delivery

Tunable ponderomotive squeezing in an optomechanical system with two coupled resonators

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Chinese Physics B 2021年第2期30卷 190-195页

作者： Qin Wu school of biomedical Engineering Guangdong Medical UniversityDongguan 523808China

We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators,where the tunable two-mode squeezing spectrum can be observed from the output *** is realized that the squeezing orientation can be controlled by the detuning between the left cavity and pump ***,both cavity decay and environment temperature play a positive role in generating better pondermotive squeezing *** squeezing spectra with a wide squeezing frequency range can be obtained by appropriate choice of parameters present in our optomechanical system.

关键词： ponderomotive squeezing light optomechanical system coupled resonators