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arXiv 2019年

作者： Sadeghi, Mahdiar Al-Radhawi, M. Ali Margaliot, Michael Sontag, Eduardo D. Departments of Electrical and Computer Engineering and of Bioengineering Northeastern University BostonMA02115 United States Department of Electrical Engineering-Systems Tel Aviv University Tel Aviv-Yafo Israel Laboratory of Systems Pharmacology Harvard Medical School BostonMA02115 United States

We consider a nonlinear SISO system that is a cascade of a scalar "bottleneck entrance" and an arbitrary Hurwitz positive linear system. This system entrains i.e. in response to a T-periodic inflow every solution converges to a unique T-periodic solution of the system. We study the problem of maximizing the averaged throughput via controlled switching. The objective is to choose a periodic inflow rate with a given mean value that maximizes the averaged outflow rate of the system. We compare two strategies: 1) switching between a high and low value, and 2) using a constant inflow equal to the prescribed mean value. We show that no switching policy can outperform a constant inflow rate, though it can approach it asymptotically. We describe several potential applications of this problem in traffic systems, ribosome flow models, and scheduling at security checks. Copyright © 2019, The Authors. All rights reserved.

关键词： Switching

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Characterization of TOF-PET detectors for a second generation radiofrequency-penetrable PET insert for simultaneous PET/MRI

Characterization of TOF-PET detectors for a second generatio...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Qian Dong Brian J. Lee Chen-Ming Chang Ilaria Sacco Ronald D. Watkins Peter Fischer Emily Anaya Craig S. Levin Departments of Electrical Engineering and Radiology Stanford University Stanford CA USA Departments of Mechanical Engineering and Radiology Stanford University Stanford CA USA Departments of Applied Physics and Radiology Stanford University Stanford CA USA Department of Radiology Stanford University Stanford CA USA Department of Computer Science Heidelberg University Mannheim Germany Departments of Radiology Electrical Engineering Bioengineering and Physics Stanford University and Molecular Imaging Program at Stanford (MIPS) Stanford CA USA

ISBN: (数字)9781728141640

ISBN: (纸本)9781728141657

Simultaneous PET/MRI combines two powerful and complementary modalities, providing multiparametric information to assess the anatomic as well as biochemical basis of disease. However, the high cost of the current commercial integrated PET/MRI systems limit the long-term potential, accessibility, and availability of PET/MRI. A portable PET insert provides a cost- effective alternative to achieve simultaneous PET/MRI for the sites that are already equipped with MR systems. Therefore, we are developing a radiofrequency (RF)-penetrable MR-compatible time-of-flight (TOF)-PET insert that can acquire simultaneous PET/MR data using the MR systems built-in body coil for RF transmission. In this study, we characterized performance of two detector modules in the MR bore under four different MRI conditions: B 0 only, echo planar imaging (EPI), gradient echo (GRE), and fast spin echo (FSE), each running for 15 minutes. The one-hour study results for coincidence timing resolution, energy resolution, coincidence count rate and ASIC chip temperature of two detector modules demonstrate the PET performance stability as well as the MR compatibility of the PET detectors under different MRI sequences. The global coincidence timing and energy resolution achieved was 264.21 ± 4.82 ps FWHM and 13.66 ± 0.08 % FWHM, respectively.

关键词： Detectors Clocks Energy resolution Magnetic resonance imaging Timing Positron emission tomography Radio frequency

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Analysis of a reduced model of epithelialmesenchymal fate determination in cancer metastasis as a singularly-perturbed monotone system

arXiv

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arXiv 2019年

作者： Al-Radhawi, M. Ali Sontag, Eduardo D. Departments of Bioengineering and Electrical and Computer Engineering Northeastern University 360 Huntington Avenue BostonMA02115 United States Laboratory of Systems Pharmacology Program in Therapeutic Science Harvard Medical School BostonMA02115

Tumor metastasis is one of the main factors responsible for the high fatality rate of cancer. Metastasis can occur after malignant cells transition from the epithelial phenotype to the mesenchymal phenotype. This transformation allows cells to migrate via the circulatory system and subsequently settle in distant organs after undergoing the reverse transition. The core gene regulatory network controlling these transitions consists of a system made up of coupled SNAIL/miRNA-34 and ZEB1/miRNA-200 subsystems. In this work, we formulate a mathematical model and analyze its long-term behavior. We start by developing a detailed reaction network with 24 state variables. Assuming fast promoter and mRNA kinetics, we then show how to reduce our model to a monotone four-dimensional system. For the reduced system, monotone dynamical systems theory can be used to prove generic convergence to the set of equilibria for all bounded trajectories. The theory does not apply to the full model, which is not monotone, but we briefly discuss results for singularly-perturbed monotone systems that provide a tool to extend convergence results from reduced to full systems, under appropriate time separation assumptions. Copyright © 2019, The Authors. All rights reserved.

关键词： Diseases

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Approaches to improving the detection sensitivity of optical modulation based radiation detection method for positron emission tomography

Approaches to improving the detection sensitivity of optical...

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： Yuli Wang Li Tao Craig S. Levin Jianfeng Xu Electrical and computer Engineering University of California Santa Cruz Santa Cruz USA Department of Electrical Engineering Stanford University Stanford CA USA Departments of Radiology Physics Electrical Engineering and Bioengineering Stanford University Stanford CA USA State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong Univ. of Sci. and Tech. Wuhan China

ISBN: (数字)9781728141640

ISBN: (纸本)9781728141657

In this paper, two approaches to improving the detection sensitivity of the optical modulation based radiation detection method for positron emission tomography (PET) have been investigated utilizing BSO, CdTe and PbBiGa as detector crystals. We first explored the magic angle of our two-crossed-polarizers based setup, of which the detection sensitivity could be improved by 15% at the magic angle. We then investigated the dependence of the detection sensitivity on the electric field distribution as well as on the crystal bias voltage with CdTe and PbBiGa crystals. Both the electric field distribution (i.e., electrode pattern) and applied bias voltage could affect the magnitude of the modulation signal and thus affect the setup's detection sensitivity. From our findings, we can conclude that a more concentrated electric field distribution (or a smaller electrode) could contribute to a better detection sensitivity. Besides, the detection sensitivity increases linearly with the bias voltage for all detector crystals and thus we could improve the detection sensitivity by adding higher bias voltage to the detector crystal.

关键词： Crystals Sensitivity Electrodes Optical modulation Detectors II-VI semiconductor materials

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Investigation of optical property modulation based ionizing radiation detection method for PET: two-crossed-polarizers based method

Investigation of optical property modulation based ionizing ...

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IEEE Symposium on Nuclear Science (NSS/MIC)

ISBN: (数字)9781728141640

ISBN: (纸本)9781728141657

In this paper, a novel optical setup based on two-crossed-polarizers is introduced to achieve ionizing radiation detection, which is an easy-build-up setup with equivalent ionizing radiation detection ability as previous work [1], [2], [3]. The performance of our proposed setup with Lithium Niobate (LiNbO 3 ) and Cadmium Telluride (CdTe) detector crystals was evaluated. The 511keV photons induced modulation signal could be detected using two-crossed-polarizer based method with LiNbO 3 and CdTe as detector. Moreover, the strength of modulation signal is linear proportion with bias voltage before being saturated. Due to LiNbO 3 's high resistivity (which could reduce the dark current), its modulation signal strength keeps increased trend after 2000V, while that signal of CdTe tended to be saturated at voltage higher than 1200V since CdTe with lower resistivity. Therefore, to improve the detection sensitivity for 511keV, we could further increase the bias voltage for detector crystals (especially for detector with high resistivity).

关键词： II-VI semiconductor materials Cadmium compounds Lithium niobate Detectors Optical modulation Ultrafast optics

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Benchmark problems for transcranial ultrasound simulation: Intercomparison of compressional wave models

arXiv

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arXiv 2022年

作者： Aubry, Jean-Francois Bates, Oscar Boehm, Christian Pauly, Kim Butts Christensen, Douglas Cueto, Carlos Gélat, Pierre Guasch, Lluis Jaros, Jiri Jing, Yun Jones, Rebecca Li, Ningrui Marty, Patrick Montanaro, Hazael Neufeld, Esra Pichardo, Samuel Pinton, Gianmarco Pulkkinen, Aki Stanziola, Antonio Thielscher, Axel Treeby, Bradley Van't Wout, Elwin Physics for Medicine Paris INSERM U1273 ESPCI Paris PSL University CNRS UMR 8063 France Department of Bioengineering Imperial College London Exhibition Road LondonSW7 2AZ United Kingdom Institute of Geophysics ETH Zürich Sonneggstrasse 5 Zürich8092 Switzerland Department of Radiology Stanford University StanfordCA United States Department of Biomedical Engineering Department of Electrical and Computer Engineering University of Utah United States Department of Surgical Biotechnology Division of Surgery and Interventional Science University College London LondonNW3 2PF United Kingdom Earth Science and Engineering Department Imperial College London London United Kingdom Centre of Excellence IT4Innovations Faculty of Information Technology Brno University of Technology Bozetechova 2 Brno612 00 Czech Republic Graduate Program in Acoustics The Pennsylvania State University University Park PA16802 United States Joint Department of Biomedical Engineering University of North Carolina at Chapel Hill North Carolina State University NC United States Department of Electrical Engineering Stanford University StanfordCA United States Zurich Switzerland Laboratory for Acoustics / Noise control Empa Swiss Federal Laboratories for Materials Science and Technology Dubendorf Switzerland Zurich Switzerland Radiology and Clinical Neurosciences Departments Cumming School of Medicine University of Calgary Canada Department of Applied Physics University of Eastern Finland Kuopio70211 Finland Department of Medical Physics and Biomedical Engineering University College London Gower Street LondonWC1E 6BT United Kingdom Technical University of Denmark Denmark Danish Research Center for Magnetic Resonance Copenhagen University Hospital Hvidovre Denmark Institute for Mathematical and Computational Engineering School of Engineering and Faculty of Mathematics Pontificia Universidad Catolica de Chile Santiago Chile

Computational models of acoustic wave propagation are frequently used in transcranial ultrasound therapy, for example, to calculate the intracranial pressure field or to calculate phase delays to correct for skull distortions. To allow intercomparison between the different modeling tools and techniques used by the community, an international working group was convened to formulate a set of numerical benchmarks. Here, these benchmarks are presented, along with intercomparison results. Nine different benchmarks of increasing geometric complexity are defined. These include a single-layer planar bone immersed in water, a multi-layer bone, and a whole skull. Two transducer configurations are considered (a focused bowl and a plane piston), giving a total of 18 permutations of the benchmarks. Eleven different modeling tools are used to compute the benchmark results. The models span a wide range of numerical techniques, including the finite-difference time-domain method, angular-spectrum method, pseudospectral method, boundary-element method, and spectral-element method. Good agreement is found between the models, particularly for the position, size, and magnitude of the acoustic focus within the skull. When comparing results for each model with every other model in a cross comparison, the median values for each benchmark for the difference in focal pressure and position are less than 10% and 1 mm, respectively. The benchmark definitions, model results, and intercomparison codes are freely available to facilitate further comparisons. Copyright © 2022, The Authors. All rights reserved.

关键词： Bone

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Clinical Translation of Nanomedicine:New Contrast Agents for Image-Guided Cancer Diagnostics and Surgery

Clinical Translation of Nanomedicine:New Contrast Agents for...

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The 3rd International Conference on Nanomedicine of China（ChinaNanomedicine 2018）

作者： Shuming Nie Departments of Bioengineering ChemistryElectrical and Computer EngineeringUniversity of Illinois at Urbana-Champaign College of Engineering and Applied Sciences Nanjing University

Nanomedicine is an area of considerable current interest in biomedical engineering because of its broad applications in biomedical imaging,in-vitro diagnostics,and targeted *** basic rationale is that nanometer-sized particles such as quantum dots,colloidal gold,and polymeric nanomicelles have functional and structural properties that are not available from either discrete molecules or bulk *** conjugated with targeting ligands such as monoclonal antibodies,peptides or small molecules,these nanoparticles can be used to target malignant tumor cells and the tumor microenvironment(such as tumor stroma and tumor vasculatures) with high specificity and *** the "mesoscopic" size range of 10-100 nm,nanoparticles also have large surface areas for conjugating to multiple diagnostic and therapeutic agents,opening new possibilities in imaging,therapy,and *** the present,however,there are several fundamental problems and technical barriers that must be understood and *** this talk,I will discuss the major challenges and opportunities in the development of nanomedicine for intraoperative cancer detection,molecular diagnostics,and image-guided surgery.

关键词： Clinical Translation of Nanomedicine:New Contrast Agents for Image-Guided Cancer Diagnostics and Surgery

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Quantitative second-harmonic generation imaging of tissue damage from environmental-scanning electron microscopy

Quantitative second-harmonic generation imaging of tissue da...

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Frontiers in Optics, FIO 2018

作者： Lee, Woowon Toussaint, Kimani C. University of Illinois at Urbana-Champaign Department of Mechanical Science and Engineering UrbanaIL United States University of Illinois at Urbana-Champaign PROBE Lab. UrbanaIL United States University of Illinois at Urbana-Champaign Departments of Electrical and Computer Engineering and Bioengineering UrbanaIL United States

We quantitatively evaluate changes of collagenous tissue due to beam exposure in an environmental-scanning electron microscope. Quantitative second-harmonic generation microscopy is used to image and assess selected r... 详细信息

ISBN: (纸本)9781943580460

关键词： Harmonic generation

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Efficient and Stable Thin‐Film Luminescent Solar Concentrators Enabled by Near‐Infrared Emission Perovskite Nanocrystals

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Angewandte Chemie 2020年第20期132卷

作者： Jiajing Wu Jianyu Tong Yuan Gao Aifei Wang Tao Zhang Hairen Tan Shuming Nie Zhengtao Deng College of Engineering and Applied Sciences Nanjing National Laboratory of Microstructures Nanjing University Nanjing Jiangsu 210023 P. R. China Departments of Bioengineering Chemistry Electrical and Computer Engineering and Materials Science and Engineering University of Illinois at Urbana-Champaign Urbana IL 61801 USA

A novel triphenylphosphine (TPP) treatment strategy was developed to prepare the near‐infrared emission CsPbI 3 nanocrystal (NC)‐polymer composite thin‐film luminescent solar concentrators (LSCs) featuring high absolute photoluminescence quantum yield (PLQY), low reabsorption, and high stability. The PL emission of the LSCs is centered at about 700 nm with 99.4±0.4 % PLQY and narrow full width at half maximum (FWHM) of 75 meV (30 nm). Compared with LSCs prepared with classic CsPbI 3 NCs, the stability of the LSCs after TPP treatments has been greatly improved, even after long‐term (30 days) immersion in water and strong mercury‐lamp irradiation (50 mW cm −2 ). Owing to the presence of lone‐pair electrons on the phosphorus atom, TPP is also used as a photoinitiator, with higher efficiency than other common photoinitiators. Large‐area (ca. 75 cm 2 ) infrared LSCs were achieved with a high optical conversion efficiency of 3.1 % at a geometric factor of 10.

关键词： Bleihalogenide Lumineszierende Solarkonzentratoren Nanokristalle Perowskite Polymerkomposite

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Breast cancer histopathology using infrared spectroscopic imaging: The impact of instrumental configurations

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Clinical Spectroscopy 2021年 3卷

作者： Shachi Mittal Tomasz P. Wrobel Michael Walsh Andre Kajdacsy-Balla Rohit Bhargava Department of Bioengineering and Beckman Institute for Advanced Science and Technology University of Illinois at Urbana−Champaign Urbana IL United States Department of Materials Science and Biomedical Engineering University of Wisconsin – Eau Claire WI United States Department of Pathology University of Illinois at Chicago IL United States Departments of Mechanical Science and Engineering Electrical and Computer Engineering Chemical and Biomolecular Engineering and Chemistry University of Illinois at Urbana−Champaign Urbana IL United States Cancer Center at Illinois University of Illinois at Urbana−Champaign Urbana IL United States

Digital analysis of cancer specimens using spectroscopic imaging coupled to machine learning is an emerging area that links spatially localized spectral signatures to tissue structure and disease. In this study, we examine the role of spatial-spectral tradeoffs in infrared spectroscopic imaging configurations for probing tumors and the associated microenvironment profiles at different levels of model complexity. We image breast tissue using standard and high-definition Fourier Transform Infrared (FT-IR) imaging and systematically examine the localization, spectral origins, and utility of data for classification. Results demonstrate that higher spatial detail provides high sensitivity and specificity of tissue segmentation, despite the increased subcellular variability. High definition imaging also allows accurate analysis of complex, multiclass models of breast tissue without compromising accuracy. A comparison of results also highlights the key differences in the data distributions and classification performance across modalities to better guide decision making for acquiring and analyzing IR imaging data for specific histopathological models.

关键词： High definition imaging Standard definition Breast pathology Machine learning Tissue segmentation

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