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Simulation and quantitative analysis of fluorescence intensity distribution based on the Monte Carlo method

Journal of Innovative Optical Health Sciences 2015年第6期8卷 67-80页

作者： Kun Zhou Jian Tian qiushi Zhang Xiangxi Meng Kun Yang qiushi ren Department of Biomedicine and Engineering College of Engineering Peking University No.5 Yiheyuan RoadBeijing 100871P.R.China Institute for Drug and Instrument Control of PLA Beijing P.R.China

The Monte Carlo method is a versatile simulation algorithm to model the propagation of photons inside the biological *** has been applied to the reconstruction of the fluorescence molecular tomography(FMT).However,such method suffers from low computational efficiency,and the time consumption is not *** way to solve this problem is to introduce a priori knowledge which will facilitate iterative *** presented an in vivo simulation environment for°uorescence molecular tomography(ISEFMT)using the Monte Carlo method to simulate the photon distribution of fluorescent objects and their sectional view in any direction quantitatively.A series of simulation experiments were carried out on different phantoms each with two fluorescent volumes to investigate the relationship among fluorescence intensity distribution and the excitation photon number,the locations and sizes of the fluorescence volumes,and the anisotropy coefficient.A significant principle was discovered,that along the direction of the excitation light,the fluorescent volume near the excitation point will provide shelter effect so that the energy of the fluorescent volume farther away from the excitation point is relatively *** quantitative analysis,it was discovered that both the photon energy distribution on every cross section and the fluorescence intensity distributed in the two volumes exhibit exponential *** two maximum positions in this distribution correspond to the centers of fluorescent ***,we also explored the effect of the phantom coefficients on the exponential rule,and found out that the exponential rule still exists,only the coefficient of the exponential rule *** results can be utilized in locating the positions of multiple fluorescent volumes in complicated FMT reconstruction involving multiple fluorescent ***,a priori knowledge can be generalized,which would accelerate the reconstruction of FMT and even other images.

关键词： Monte Carlo simulation FMT quantitative

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Hacking the optical diffraction limit: Review on recent developments of fluorescence nanoscopy

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Chinese Science Bulletin 2011年第18期56卷 1857-1876页

作者： DING YiChen XI Peng ren qiushi Department of Biomedical Engineering College of Engineering Peking University Beijing 100871 China

Subject to the diffraction limit, the resolution of conventional optical microscopy is constrained to about 200 and 500 nm in the lateral and axial planes, respectively. The advantage of optical microscopy in the life sciences over electronic microscopy, especially fluorescence microscopy, drives scientists to develop novel "hacks" to reach nanoscale resolutions by optical means. In this review, three aspects of the techniques are discussed: (1) lateral super-resolution; (2) axial super-resolution; (3) super-resolution in three dimensions. The principles of how the methods achieve the cross-barrier resolution are discussed, and recent advances in current techniques are described. With these methods, the use of fluorescence microscopy is growing quickly toward a new era: fluorescence nanoscopy that will reveal 2 orders of magnitude more information on cellular structure and dynamics.

关键词：光学显微镜荧光显微镜衍射极限黑客入侵超分辨率电子显微镜超高分辨率 “黑客”

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Fibronectin-targeted dual-acting micelles for combination therapy of metastatic breast cancer

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Signal Transduction and Targeted Therapy 2020年第1期5卷 2384-2394页

作者： Zhuoran Gong Min Chen qiushi ren Xiuli Yue Zhifei Dai Department of Biomedical Engineering College of EngineeringPeking UniversityBeijing 100871China School of Environment Harbin Institute of TechnologyHarbin 150090China

Stage IV breast cancer,which has a high risk of invasion,often develops into metastases in distant organs,especially in the lung,and this could threaten the lives of ***,the development of more advanced therapeutics that can efficiently target metastatic foci is *** this study,we built an dual-acting therapeutic strategy using micelles with high stability functionalized with fibronectin-targeting CREKA peptides encapsulating two slightly soluble chemotherapy agents in water,doxorubicin(D)and vinorelbine(V),which we termed *** found that small C-DVM micelles could efficiently codeliver drugs into 4T1 cells and disrupt microtubule structures.C-DVM also exhibited a powerful ability to eradicate and inhibit invasion of 4T1 ***,an in vivo pharmacokinetics study showed that C-DVM increased the drug circulation half-life and led to increased enrichment of drugs in lung metastatic foci after 24 ***,dual-acting C-DVM treatment led to 90%inhibition of metastatic foci development and reduced invasion of metastases.C-DVM could potentially be used as a targeted treatment for metastasis and represents a new approach with higher therapeutic efficacy than conventional chemotherapy for stage IV breast cancer that could be used in the future.

关键词： drugs chemotherapy organs

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Vision implants:An electrical device will bring light to the blind

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Science in China(Series F) 2008年第1期51卷 101-110页

作者： NIU JinHai LIU YiFei ren qiushi ZHOU Yang ZHOU Ye NIU Shuai Department of Biomedical Engineering Institute for Laser Medicine and Bio-Photonics Shanghai Jiao Tong University Shanghai 200240 China

Cochlear implant has been successfully applied in clinic. Recent research indicates vision implants may be the potential way to restore sight for the blind. Here, principle and common structure of vision implants are introduced. Main vision approaches of retinal, optic nerve, and cortical prosthesis are reviewed. In our progress, electrical response at visual cortex is recorded, when penetrating electrodes stimulate rabbit optic nerve, vision implants based on optic nerve stimulator chip （ONSC） and Chipcon radio frequency （RF） chip are under developing. Despite several obstacles to overcome, promising results in animal and human experiments give scientists confidence that artificial vision implants will bring light to the blind in the near future.

关键词： vision implants electrical devices retinal optic nerve cortical prosthesis

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Mirror-enhanced super-resolution microscopy

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Light(Science & Applications) 2016年第1期5卷 357-364页

作者： Xusan Yang Hao Xie Eric Alonas Yujia Liu Xuanze Chen Philip J Santangelo qiushi ren Peng Xi Dayong Jin Department of Biomedical Engineering College of EngineeringPeking UniversityNo.5 Yiheyuan RoadBeijing 100871China Wallace H Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory UniversityAtlantaGA 30332USA Advanced Cytometry Labs ARC Centre of Excellence for Nanoscale BioPhotonics(CNBP)Macquarie UniversitySydneyNSW 2109Australia Institute for Biomedical Materials and Devices(IBMD) Faculty of ScienceUniversity of Technology SydneySydneyNSW 2007Australia

Axial excitation confinement beyond the diffraction limit is crucial to the development of next-generation,super-resolution *** Emission Depletion(STED)nanoscopy offers lateral super-resolution using a donut-beam depletion,but its axial resolution is still over 500 *** internal reflection fluorescence microscopy is widely used for single-molecule localization,but its ability to detect molecules is limited to within the evanescent field of~100 nm from the cell attachment *** find here that the axial thickness of the point spread function(PSF)during confocal excitation can be easily improved to 110 nm by replacing the microscopy slide with a *** interference of the local electromagnetic field confined the confocal PSF to a 110-nm spot axially,which enables axial super-resolution with all laser-scanning *** sectioning can be obtained with wavelength modulation or by controlling the spacer between the mirror and the *** no additional complexity,the mirror-assisted excitation confinement enhanced the axial resolution six-fold and the lateral resolution two-fold for STED,which together achieved 19-nm resolution to resolve the inner rim of a nuclear pore complex and to discriminate the contents of 120 nm viral *** ability to increase the lateral resolution and decrease the thickness of an axial section using mirror-enhanced STED without increasing the laser power is of great importance for imaging biological specimens,which cannot tolerate high laser power.

关键词： confocal interference point spread function super-resolution

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A machine learning-based algorithm used to estimate the physiological elongation of ocular axial length in myopic children

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Eye and Vision 2020年第1期7卷 485-496页

作者： Tao Tang Zekuan Yu Qiong Xu Zisu Peng Yuzhuo Fan Kai Wang qiushi ren Jia Qu Mingwei Zhao Department of Ophthalmology&Clinical Centre of Optometry Peking University People’s HospitalBeijing 100044China College of Optometry Peking University Health Science CenterBeijingChina Eye Disease and Optometry Institute Peking University People’s HospitalBeijingChina Beijing Key Laboratory of the Diagnosis and Therapy of Retinal and Choroid Diseases BeijingChina Academy for Engineering&Technology Fudan UniversityShanghaiChina Department of Biomedical Engineering College of EngineeringPeking UniversityBeijing 100871China School of Ophthalmology and Optometry and Eye Hospital Wenzhou Medical UniversityWenzhouZhejiangChina

Background:Axial myopia is the most common type of ***,due to the high incidence of myopia in Chinese children,few studies estimating the physiological elongation of the ocular axial length(AL),which does not cause myopia progression and differs from the non-physiological elongation of AL,have been *** purpose of our study was to construct a machine learning(ML)-based model for estimating the physiological elongation of AL in a sample of Chinese school-aged myopic ***:In total,1011 myopic children aged 6 to 18 years participated in this ***-sectional datasets were used to optimize the ML *** input variables included age,sex,central corneal thickness(CCT),spherical equivalent refractive error(SER),mean K reading(K-mean),and white-to-white corneal diameter(WTW).The output variable was AL.A 5-fold cross-validation scheme was used to randomly divide all data into 5 groups,including 4 groups used as training data and one group used as validation *** types of ML algorithms were implemented in our *** best-performing algorithm was applied to predict AL,and estimates of the physiological elongation of AL were obtained as the partial derivatives of AL_(predicted)-age curves based on an unchanged SER value with increasing ***:Among the six algorithms,the robust linear regression model was the best model for predicting AL,with a R^(2) value of 0.87 and relatively minimal averaged errors between the predicted AL and true *** on the partial derivatives of the AL_(predicted)-age curves,the estimated physiological AL elongation varied from 0.010 to 0.116 mm/year in male subjects and 0.003 to 0.110 mm/year in female subjects and was influenced by age,SER and *** to the model,the physiological elongation of AL linearly decreased with increasing age and was negatively correlated with the SER and the ***:The physiological elongation of the AL is rarely recorded in clinical data in

关键词： Myopia Myopia progression Machine learning Ocular axial length Physiological elongation Orthokeratology

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Early changes to the extracellular space in the hippocampus under simulated microgravity conditions

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Science China(Life Sciences) 2022年第3期65卷 604-617页

作者： Yajuan Gao Hongbin Han Jichen Du Qingyuan He Yanxing Jia Junhao Yan Hui Dai Bin Cui Jing Yang Xunbin Wei Liu Yang Rui Wang ren Long qiushi ren Xing Yang Jiabin Lu Department of Radiology Peking University Third HospitalBeijing 100191China Institute of Medical Technology Peking University Health Science CenterBeijing 100191China Beijing Key Laboratory of Magnetic Resonance Imaging Technology Beijing 100191China Department of Neurology Aerospace Center HospitalPeking University Aerospace Clinical CollegeBeijing 100039China State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical SciencesPeking UniversityBeijing 100191China Department of Anatomy and Histology School of Basic Medical SciencesPeking UniversityBeijing 100191China NHC Key Laboratory of Medical Immunology Department of ImmunologySchool of Basic Medical SciencesPeking UniversityBeijing 100191China Department of Radiology Aerospace Center HospitalPeking University Aerospace Clinical CollegeBeijing 100039China

The smooth transportation of substances through the brain extracellular space(ECS)is crucial to maintaining brain function;however,the way this occurs under simulated microgravity remains *** this study,tracer-based magnetic resonance imaging(MRI)and DECS-mapping techniques were used to image the drainage of brain interstitial fluid(ISF)from the ECS of the hippocampus in a tail-suspended hindlimb-unloading rat model at day 3(HU-3)and 7(HU-7).The results indicated that drainage of the ISF was accelerated in the HU-3 group but slowed markedly in the HU-7 *** tortuosity of the ECS decreased in the HU-3 group but increased in the HU-7 group,while the volume fraction of the ECS increased in both *** diffusion rate within the ECS increased in the HU-3 group and decreased in the HU-7 *** alterations to ISF drainage and diffusion in the ECS were recoverable in the HU-3 group,but neither parameter was restored in the HU-7 *** findings suggest that early changes to the hippocampal ECS and ISF drainage under simulated microgravity can be detected by tracer-based MRI,providing a new perspective for studying microgravity-induced nano-scale structure abnormities and developing neuroprotective approaches involving the brain ECS.

关键词： brain extracellular space interstitial fluid interstitial system tracer-based magnetic resonance imaging simulated microgravity hindlimb-unloading

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Bloodletting at Jing-well points decreases interstitial fluid flow in the thalamus of rats

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Journal of Traditional Chinese Medicine 2016年第1期36卷 107-112页

作者： FuYu LiYuliang GuoJia Liu Bin Liu Huipo Zhang Weibo Sun Wanli GaoYajuan ren qiushi Han Haojun Department of Neurology Peking University Third Hospital Beijing 100191 China Beijing Key Lab of Magnetic Resonance Imaging Device and Technique Beijing 100191 China Department of Biomedical Engineering College of engineering of Peking University Beijing 100191 China Department of Interventional Medicine The Second Hospital of Shandong University Jinan 250033China Institute of Applied Physics and Computational Mathematics Beijing 100094 China Institute of Acupuncture and Moxibustion China Academy of Chinese Medical Sciences Beijing 100700China Beijing Key Lab of Magnetic Resonance Imaging Device and Technique Department of Biomedical Engineering College of engineering of Peking University Department of Radiology Peking University Third Hospital Beijing 100191 China Chang Zhi Medical College Chang Zhi 046000 China

OBJECTIVE：To investigate the changes in the neuronal microenvironment of the middle cerebral artery （MCA） territory induced by Jing-well points bloodletting acupuncture （WPBA） and to explore the neuroprotective mechanism of WPBA in stroke. METHODS： Adult male Sprague Dawley （n = 32） rats were randomly divided into four groups of eight animals each： WPBA-thalamus group （WT）, WPBA-caudate nucleus group （WC）, sham-control thalamus group （ST） and sham-control caudate nucleus group （SC）. Animals in the WT and WC groups received 2 I-μL of the extracellular tracer gadolinium-diethylene triamine pentaacetic acid （Gd-DTPA） injected into the thalamus or caudate nucleus, respectively, and 12 Jing-well points in the distal ends of the rats＇ digits were used for WPBA. Although 2 μL of Gd-DTPA was injected into the thalamus or caudate nucleus, respectively, for animals in the two sham groups （ST and SC）, no acupuncture or bloodletting was performed. Brain extracellular space and interstitial fluid flow parameters were measured using Gd-DTPA-enhanced magnetic reso- nance imaging. RESULTS： The brain interstitial fluid flow speed was decreased in the thalamus after WPBA, with a significantly lower Gd-DTPA clearance rate and longer half-life of Gd-DTPA in the thalamus of treated rats than those in sham-control rats [WPBA-treated rats＇clearance rate, （7.47 ± 3.15） x 10^-5/s （P = 0.009）; half-life, （1.52 ± 0.13） h, P = 0.000]. By contrast, no significant changes in brain extracellular space and interstitial fluid flow parameters were detected in the caudate nucleus after WPBA （P = 0.649）. In addi- tion, no differences in the morphology of the brain extracellular space or the final distribution of the traced brain interstitial fluid were demonstrated be- tween theWT and WC groups （P = 0.631, P = 0.970, respectively）. CONCLUSION： The WPBA decreased the speed of the local thalamic ISF flow in rats, which is assumed to be a beneficial protection by down-modulated the metabolic rate of the

关键词： Bloodletting Extracellular space Gado-linium ethoxybenzyl DTPA Interstitial fluid Magnetic resonance imaging

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A Novel Design of Control Circuit in Neural Stimulator for Optic Nerve Prostheses

A Novel Design of Control Circuit in Neural Stimulator for O...

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2006 8th International Conference on Signal Processing

作者： Ying Zhao Jia Wang qiushi ren Xinyu Chai Biomedical Engineering Department of Shanghai Jiao Tong University

＜正＞More recent studies show that electrical micro-stimulation of the retina or cortex produces visual sensations in blinds ***, with current electrode array technologies,it is nearly impossible to cover entire visual field by electrically stimulating the retina or visual cortex. In the visual pathway,by stimulating optic nerve, the entire visual filed is represented in such a relatively small *** to physiological experiment results,we design a kind of implantable neural stimulator based on stimulating optic nerve to generate visual *** control circuit is designed to control 64 electrodes,offer single pulse or multiple pulses sequence which are variable range such as from 1μA to 2.048 mA current amplitudes,from 21μs to 400μs duration,from 0 to 350Hz frequency.

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影响制冷机长周期运行的参数分析与控制

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油气田地面工程 2010年第7期29卷 76-77页

作者：任秋实大庆炼化公司聚合物一厂

丙烯腈装置的关键设备离心式制冷机主要是为剧毒物质氢氰酸生产提供冷量。它的平稳与否,对装置的安全生产具有很大影响。因此,深入研究、掌握、分析监控机组的关键运行参数对维护制冷机的长周期运行至关重要。

关键词：供油温度供油差压蒸发压力冷凝压力

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