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Microwave/Thermal Analyses for Human Bone Characterization

Journal of Biomedical Science and Engineering 2016年第2期9卷 101-111页

作者： Vinay Kumar Suryadevara Suyog Patil james rizkalla Ahdy Helmy Paul Salama Maher rizkalla Department of Electrical and Computer Engineering Indiana University-Purdue University Indianapolis Indianapolis USA Indiana University School of Medicine Indianapolis USA Integrated Nanosystems Development Institute (INDI) Indiana University-Purdue University Indianapolis Indianapolis USA

A novel imaging approach utilizing microwave scattering was proposed in order to analyze various properties of bone. Microwave frequencies of 900 MHz, 1 GHz, and 2.4 GHz were used during this study. This investigation’s objectives were to emphasize characteristics of abnormalities in human bones and to detect fine fractures through contrasts in bone density. The finite element method (FEM) presented here is generated from COMSOL software at different frequencies. The study identified the optimum transmission directed at the interface layers from an external microwave source. It was found that approximately 900 MHz microwave power was ideal for this application. This can be attributed to the penetration depth where the power dissipation is analyzed based on bone condition. The microwave energy was generated from an exterior antenna that was interfaced, via catheter, to skeletal bone. The power transmitted to bone was converted into thermal energy, and has led to a visible temperature distribution pattern, which reflects the bone density level, and accordingly, the type of bone under investigation. The electrical and thermal properties, including the dielectric permittivity, thermal conductivity, and heat flux absorption through the bone substance, have great implications on the FEM distribution. The boundary conditions using tangential matching of field components at the tissue-bone interface were incorporated into the finite element method. The average power from the electromagnetic fields (estimated from the Poynting’s vector, P = E*H), was assumed to be fully absorbed as heat due to the conductivity of the bone material. Furthermore, microwave energy was applied as a delta function and the thermal distributions have been analyzed in order to distinguish between normal healthy bone and bones with structural or metabolic abnormalities. The latter was emulated by different bone density to contrast normal bone anatomy. The FEM simulation suggests that thermography mic

关键词： Microwave Human Bones Simulation FEM COMSOL Thermal Diagnosis

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Eletromagnetic Detection of Mild Brain Injury: A Novel Imaging Approach to Post Concussive Syndrome

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Journal of Biomedical Science and Engineering 2021年第11期14卷 347-360页

作者： james rizkalla David Botros Nasser Alqahtani Mounica Patnala Paul Salama Felipe Pablo Perez Maher rizkalla Baylor University Medical Center Dallas Texas USA John Hopkins Medicine Department of Neurology Baltimore MD USA Department of Electrical and Computer Engineering Indiana University Purdue University Indianapolis (IUPUI) In-dianapolis IN USA Department of Medicine Indiana University School of Medicine Indianapolis IN USA

Introduction: Mild traumatic brain injury (mTBI) is a common injury, with nearly 3 - 4 million cases annually in the United States alone. Neuroimaging in patients with mTBI provides little benefit, and is usually not indicated as the diagnosis is primarily clinical. It is theorized that microvascular trauma to the brain may be present in mTBI, that may not be captured by routine MRI and CT scans. Electromagnetic (EM) waves may provide a more sensitive medical imaging modality to provide objective data in the diagnosis of mTBI. Methods: COMSOL simulation software was utilized to mimic the anatomy of the human skull including skin, cranium, cerebrospinal fluid (CSF), gray-matter tissue of the brain, and microvasculature within the neural tissue. The effects of penetrating EM waves were simulated using the finite element analysis software and results were generated to identify feasibility and efficacy. Frequency ranges from 7 GHz to 15 GHz were considered, with 0.6 and 1 W power applied. Results: Variations between the differing frequency levels generated different energy levels within the neural tissue—particularly when comparing normal microvasculature versus hemorrhage from microvasculature. This difference within the neural tissue was subsequently identified, via simulation, serving as a potential imaging modality for future work. Conclusion: The use of electromagnetic imaging of the brain after concussive events may play a role in future mTBI diagnosis. Utilizing the proper depth frequency and wavelength, neural tissue and microvascular trauma may be identified utilizing finite element analysis.

关键词： Brain Injury Trauma Imaging Simulation COMSOL

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Computer Simulation/Practical Models for Human Thyroid Thermographic Imaging

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Journal of Biomedical Science and Engineering 2015年第4期8卷 246-256页

作者： james rizkalla William Tilbury Ahdy Helmy Vinay Kumar Suryadevara Maher rizkalla Michael M. Holdmann Indiana University School of Medicine Indianapolis IN USA Indiana University School of Medicine/VA Hospital Indianapolis IN USA Department of Electrical and Computer Engineering Purdue School of Engineering and Technology Indianapolis IN USA

We have demonstrated a successful computer model utilizing ANSIS software that is verified with a practical model using Infrared (IR) sensors. The simulation model incorporates the three heat transfer coefficients: conduction, convection, and radiation. While the conduction component was a major contributor to the simulation model, the other two coefficients have added to the accuracy and precision of the model. Convection heat allows for the influence of blood flow within the study, while the radiation aspect, sensed through IR sensors, links the practical model of the study. This study also compares simulation data with the applied model generated from IR probe sensors. These sensors formed an IR scanner that moved via servo mechanical system, tracking the temperature distribution within and around the thyroid gland. These data were analyzed and processed to produce a thermal image of the thyroid gland. The acquired data were then compared with an Iodine uptake scan for the same patients.

关键词： Thyroid Thermography Computer Simulation Imaging Practical Model IR Sensors

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Electromagnetic and Thermal Simulations of Human Neurons for SAR Applications

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Journal of Biomedical Science and Engineering 2016年第9期9卷 437-444页

作者： Felipe Perez Gilbert Millholland Seshasai Vamsi Krishna Peddinti Ashok Kumar Thella james rizkalla Paul Salama Maher rizkalla Jorge Morisaki Maher E. rizkalla Department of Medicine Indiana University School of Medicine Indianapolis IN USA Department of Electrical and Computer Engineering (ECE) Indiana University Purdue University Indianapolis (IUPUI) Indianapolis IN USA Indiana University School of Medicine Indiana University Purdue University Indianapolis (IUPUI) Indianapolis IN USA Department of Bioengineering University of Illinois at Chicago Chicago IL USA Integrated Nanosystems Development Institute (INDI) Indiana University Purdue University Indianapolis (IUPUI) Indianapolis IN USA

The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by HN for medical diagnosis and treatment. Research issues including the wave frequency, power intensity, reflections and scattering, and penetration depths are of important considerations to be incorporated into the research study. In this study, computer simulation for the EM exposure to HN was studied for the purpose of determining the upper limits of the electric and magnetic field intensities, power consumption, reflections and transmissions, and the change in temperature resulting from the power absorption by human neurons. Both high frequency structural simulators (HFSS) from ANSYS software, and COMSOL multi-physics were used for the simulation of the EM transmissions and reflections, and the temperature profile within the cells, respectively. For the temperature profile estimation, the study considers an electrical source of 0.5 watt input power, 64 MHz. The EM simulation was looking into the uniformity of the fields within the sample cells. The size of the waveguide was set to be appropriate for a small animal model to be conducted in the future. The incident power was fully transmitted throughout the waveguide, and less than 1% reflections were observed from the simulation. The minimum reflected power near the sample under investigation was found to be with negligible reflected field strengths. The temperature profile resulting from the COMSOL simulation was found to be near 0.25 m°K, indicating no change in temperature on the neuro cells under the EM exposure. The paper details the simulation results for the EM response determined by HFSS, and temperature profile simulated by COMSOL.

关键词： EM (Electromagnetic) SAR (Specific Absorption Rate) COMSOL HFSS HN (Human Neuron)

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Photo Acoustic Thermal for Human Bone Characterization: A Feasibility Study

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Journal of Biomedical Science and Engineering 2016年第9期9卷 445-449页

作者： james rizkalla Vinay Kumar Suryadevara Ashok Kumar Thella Ahdy Helmy Paul Salama Maher E. rizkalla Indiana University School of Medicine Indianapolis IN USA Electrical and Computer Engineering Indiana University Purdue University Indianapolis (IUPUI) Indianapolis IN USA Integrated Nanosystems Development Institute (INDI) Indiana University Purdue University Indianapolis (IUPUI) Indianapolis IN USA

The possible features of photo acoustic tomography (PAT) in medical research and practice, including applications in orthopedics and cardiovascular areas, among others, have motivated the emphasis of this study towards human bone applications. PAT modality is an emerging approach that features safety and greater penetration depth compared to other modalities such as X-ray and microwave. The high-resolution images and safety related to PAT modality are attributed to the scattering properties of ultrasound as compared to light within a human tissue. PAT brought considerable attention from the medical research community to target optimum parameters for practical models. It includes source frequency penetration depth, dynamic temperature responses, and acoustic pressure throughout the multilayer structure of the human tissues. In this work, the acoustic pressure and the bio-heat equations were analyzed for power distribution and penetration depth, covering the basic principles of PAT within the human body. Three sources with three dif-ferent heat energy pulses;1 s, 3 s, and 5 s, were considered in order to study the rise time and fall time dynamic responses inside the bone material. The computer simulation was designed to simu-late the human tissue at 1 MHz with an acoustic pressure of 1 MPa. A penetration depth for all sources was estimated to be near 4 cm with a temperature change from 0.5 K to near 1 K over a pe-riod of 10 s. The simulation data provide promising results when taken to the next level of practical implementation. The 4 cm penetration depth range may enable the researchers to investigate mul-tiple layers within the human body, leading to non-invasive deterministic approach. The simulation presented here will serve as a pilot study towards photoacoustic applications in orthopedic applica-tions.

关键词： Photoacoustic Tomography PAT PA Ortho COMSOL

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Antenna Design and SAR Analysis on Human Head Phantom Simulation for Future Clinical Applications

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Journal of Biomedical Science and Engineering 2017年第9期10卷 421-430页

作者： Felipe Pablo Perez Joseph Paul Bandeira Jorge J. Morisaki Seshasai Vamsi Krishna Peddinti Paul Salama james rizkalla Maher E. rizkalla Department of Medicine Geriatric Medicine Section Indiana University School of Medicine Indianapolis USA Department of Bio-Engineering University of Illinois at Chicago Chicago USA Department of Electrical and Computer Engineering Indiana University Purdue University Indianapolis (IUPUI) Indianapolis USA Baylor University Medical Center Dallas USA

Background: The rapid development of a variety of devices that emit Radiofrequency Electromagnetic fields (RF-EMF) has sparked growing interest in their interaction with biological systems and the beneficial effects on human health. As a result, investigations have been driven by the potential for therapeutic applications, as well as concern for any possible negative health implications of these EM energies [1-4]. Recent results have indicated specific tuning of experimental and clinical RF exposure may lead to their clinical application toward beneficial health outcomes [5]. Method: In the current study, a mathematical and computer simulation model to analyze a specific RF-EMF exposure on a human head model was developed. Impetus for this research was derived from results of our previous experiments which revealed that Repeated Electromagnetic Field Stimulation (REMFS) decreased the toxic levels of beta amyloid (Aβ) in neuronal cells, thereby suggesting a new potential therapeutic strategy for the treatment of Alzheimer’s disease (AD). Throughout development of the proposed device, experimental variables such as the EM frequency range, specific absorption rate (SAR), penetration depth, and innate properties of different tissues have been carefully considered. Results: RF-EMF exposure to the human head phantom was performed utilizing a Yagi-Uda antenna type possessing high gain (in the order of 10 dbs) at a frequency of 64 MHz and SAR of 0.6 W/Kg. In order to maximize the EM power transmission in one direction, directors were placed in front of the driven element and reflectors were placed behind the driven element. So as to strategically direct the EM field into the center of the brain tissue, while providing field linearity, our analysis considered the field distribution for one versus four antennas. Within the provided dimensions of a typical human brain, results of the Bioheat equation within COMSOL Multiphysics version 5.2a software demonstrated less than a 1 m

关键词： Antenna Neuro Alzheimer Disease Diagnosis COMSOL SAR.

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Photo Acoustic Energy Applications for the Detection of Human Arterial Blockages via Multiple Skin/Bone Layers, a Non-Invasive Approach

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World Journal of Cardiovascular Diseases 2017年第8期7卷 251-270页

作者： Monika Kakani Neeraj Rathi Ahdy Helmy Ashok Kumar Thella M. D. james rizkalla Paul Salama Maher E. rizkalla Department of Electrical and Computer Engineering Indiana University Purdue University Indianapolis (IUPUI) Indianapolis USA VA Hospital Indiana University School of Medicine Indianapolis USA Baylor University Medical Center (BUMC) Dallas USA Integrated Nanosystems Development Institute IUPUI Indianapolis USA Richard G. Lugar Center for Renewable Energy IUPUI Indianapolis USA

The impact of arterial narrowing/blocking caused by plaque buildup in arteries leads to many life-threatening consequences. This is recognized as a cause in heart attacks and peripheral vascular disease. Diagnosing the illness is only feasible after symptoms have presented to the patient. Currently, the standard for visualizing coronary arteries is through angiography, which may have complications, and impact on the healthcare system. Furthermore, cardiac catheterization may also places high health risks, given its overall invasiveness. Cardiac arrhythmias, infection, and contrast dye nephrotoxicity are recognized complications within this process. Therefore, a noninvasive approach may have potentials to reduce patient complications, finances surrounding healthcare, and more efficient patient care through earlier screening and diagnosing. This research addresses a new approach using photoacoustic (PA) imaging. The transmission properties of atherosclerosis within walls of arteries, can be exploited using photo acoustics, to better visualize and characterize the degree and severity of atherosclerosis. The delivered energy is absorbed by components of the vascular tissue converted into heat, leading to transient thermos elastic expansion, which creates an acoustic emission. The thermal response was analyzed for its fall and recovery times that are attributed to the artery fat type. The control parameters, including the frequency, penetration depth, energy levels, and tissue layer sizes, for multilayered structures were considered. The structures investigated were fatty infiltrate within the artery, blood, bones, and skin, within frequency range from 1 MHz to 3 MHz, and typical tissue sizes in the milli to centimeter range. As high as 14 MPas in the acoustic pressure at 1 MHz, resulted in temperature difference of up to 3.4 K. When the operating frequency was altered to 2 MHz, the temperature changed to 23 K. Furthermore, when the frequency was changed to 3 MHz, the te

关键词： Acoustic Thermal Cardiovascular Diagnosis MEMS/NEMS COMSOL Multilayers Non-Invasive

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避世之所加拿大亚瑟住宅

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室内设计与装修 2025年第1期 46-49页

作者：无 james Brittain(摄影) coco(编译) 5468796 Architecture 不详

亚瑟住宅是为一对来自南非的夫妇设计的,他们一位是热衷园艺的木匠,另一位是急诊室医生。夫妇俩一直在寻找一个适中的“避难所”,与外界隔绝,并且有足够的空间来保护隐私。住宅所在的小区是一个成熟社区,原有的小平房正迅速被传统住宅... 详细信息

亚瑟住宅是为一对来自南非的夫妇设计的,他们一位是热衷园艺的木匠,另一位是急诊室医生。夫妇俩一直在寻找一个适中的“避难所”,与外界隔绝,并且有足够的空间来保护隐私。住宅所在的小区是一个成熟社区,原有的小平房正迅速被传统住宅取代。与此相反,亚瑟夫妇希望用一种深思熟虑的替代方案来挑战这种发展模式。

关键词：传统住宅替代方案保护隐私避难所亚瑟园艺小区加拿大

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Silk-based nerve guidance conduits with macroscopic holes modulate the vascularization of regenerating rat sciatic nerve

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Neural Regeneration Research 2025年第6期20卷 1789-1800页

作者： Carina Hromada Patrick Heimel Markus Kerbl LászlóGál Sylvia Nürnberger Barbara Schaedl james Ferguson Nicole Swiadek Xavier Monforte Johannes C.Heinzel Antal Nógrádi Andreas H.Teuschl-Woller David Hercher Department Life Science Engineering University of Applied Sciences Technikum WienViennaAustria Austrian Cluster for Tissue Regeneration ViennaAustria Ludwig Boltzmann Institute for Traumatology The Research Center in Cooperation with AUVAViennaAustria University Clinic of Dentistry Medical University of ViennaViennaAustria Department of Plastic Reconstructive and Aesthetic SurgeryLandesklinikum Wiener Neustadt2700 Wiener NeustadtAustria Department of Anatomy Histology and EmbryologyAlbert Szent-Györgyi Medical SchoolUniversity of SzegedSzegedHungary Medical University of Vienna Department of Orthopedics and Trauma SurgeryDevision of Trauma SurgeryViennaAustria Department of Hand- PlasticReconstructive and Burn SurgeryBG Unfallklinik TuebingenUniversity of TuebingenTuebingenGermany

Peripheral nerve injuries induce a severe motor and sensory deficit. Since the availability of autologous nerve transplants for nerve repair is very limited, alternative treatment strategies are sought, including the use of tubular nerve guidance conduits(tNGCs). However, the use of tNGCs results in poor functional recovery and central necrosis of the regenerating tissue, which limits their application to short nerve lesion defects(typically shorter than 3 cm). Given the importance of vascularization in nerve regeneration, we hypothesized that enabling the growth of blood vessels from the surrounding tissue into the regenerating nerve within the tNGC would help eliminate necrotic processes and lead to improved regeneration. In this study, we reported the application of macroscopic holes into the tubular walls of silk-based tNGCs and compared the various features of these improved silk^(+) tNGCs with the tubes without holes(silk^(–) tNGCs) and autologous nerve transplants in an 8-mm sciatic nerve defect in rats. Using a combination of micro-computed tomography and histological analyses, we were able to prove that the use of silk^(+) tNGCs induced the growth of blood vessels from the adjacent tissue to the intraluminal neovascular formation. A significantly higher number of blood vessels in the silk^(+) group was found compared with autologous nerve transplants and silk^(–), accompanied by improved axon regeneration at the distal coaptation point compared with the silk^(–) tNGCs at 7 weeks postoperatively. In the 15-mm(critical size) sciatic nerve defect model, we again observed a distinct ingrowth of blood vessels through the tubular walls of silk^(+) tNGCs, but without improved functional recovery at 12 weeks postoperatively. Our data proves that macroporous tNGCs increase the vascular supply of regenerating nerves and facilitate improved axonal regeneration in a short-defect model but not in a critical-size defect model. This study suggests that further optimizatio

关键词： axon regeneration blood vessel functional recovery macroporous nerve lesion peripheral nerve repair sciatic nerve silk-based nerve guidance conduit vascularization

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Treating amyotrophic lateral sclerosis with allogeneic Schwann cell-derived exosomal vesicles: a case report

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Neural Regeneration Research 2025年第4期20卷 1207-1216页

作者： Pascal J.Goldschmidt-Clermont Aisha Khan George Jimsheleishvili Patricia Graham Adriana Brooks Risset Silvera Alexander J.P.Goldschmidt Damien D.Pearse W.Dalton Dietrich Allan D.Levi james D.Guest Miller School of Medicine University of MiamiMiamiFLUSA Stem Cell Institute Miller School of MedicineUniversity of MiamiMiamiFLUSA The Miami Project to Cure Paralysis Miller School of MedicineUniversity of MiamiMiamiFLUSA Alzady International LLC MiamiFLUSA Neurological Surgery Miller School of MedicineUniversity of MiamiMiamiFLUSA

Schwann cells are essential for the maintenance and function of motor neurons,axonal networks,and the neuromuscular *** amyotrophic lateral sclerosis,where motor neuron function is progressively lost,Schwann cell function may also be ***,important signaling and potential trophic activities of Schwann cell-derived exosomal vesicles have been *** case report describes the treatment of a patient with advanced amyotrophic lateral sclerosis using serial intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles,marking,to our knowledge,the first instance of such *** 81-year-old male patient presented with a 1.5-year history of rapidly progressive amyotrophic lateral *** initial diagnosis,the patient underwent a combination of generic riluzole,sodium phenylbutyrate for the treatment of amyotrophic lateral sclerosis,and *** patient volunteered to participate in an FDA-approved single-patient expanded access treatment and received weekly intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles to potentially restore impaired Schwann cell and motor neuron *** confirmed that cultured Schwann cells obtained from the amyotrophic lateral sclerosis patient via sural nerve biopsy appeared impaired(senescent)and that exposure of the patient’s Schwann cells to allogeneic Schwann cell-derived exosomal vesicles,cultured expanded from a cadaver donor improved their growth capacity in *** a period of observation lasting 10 weeks,during which amyotrophic lateral sclerosis Functional Rating Scale-Revised and pulmonary function were regularly monitored,the patient received weekly consecutive infusions of 1.54×1012(×2),and then consecutive infusions of 7.5×1012(×6)allogeneic Schwann cell-derived exosomal vesicles diluted in 40 mL of Dulbecco’s phosphate-buffered *** of the infusions were associated with adverse events such as infusion reactions(allergic or otherwise)or

关键词： allogeneic amyotrophic lateral sclerosis exosomes infusion neuromuscular junction Schwann cell

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