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Prof. Dr. Jungwon Yoon
Gwangju Institute of Science and Technology, School of Integrated Technology, Korea

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Research Keywords & Expertise

0 Polymer Composites
0 hyperthermia
0 Toxicity of nanoparticles
0 Magnetic nanoparticles
0 Core shell nanoparticles

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Magnetic nanoparticles
hyperthermia

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Short Biography

Jungwon Yoon received a Ph.D. degree from the Department of Mechatronics, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea, in 2005. Now, he is an associate professor in the School of Integrated Technology, Gwangju Institute of Science and Technology, Gwangju, Korea. He is a Technical Editor of the IEEE/ASME Transactions on Mechatronics and Associate Editor of Frontiers in Robotics and AI. His current research interests include bio nano robot control, virtual reality haptic devices, and rehabilitation robots. He has authored or coauthored more than 160 peer-reviewed journal and conference articles.

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Journal article
Published: 18 August 2021 in International Journal of Molecular Sciences
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In magnetic hyperthermia, magnetic nanoparticles (MNPs) are used to generate heat in an alternating magnetic field to destroy cancerous cells. This field can be continuous or pulsed. Although a large amount of research has been devoted to studying the efficiency and side effects of continuous fields, little attention has been paid to the use of pulsed fields. In this simulation study, Fourier’s law and COMSOL software have been utilized to identify the heating power necessary for treating breast cancer under blood flow and metabolism to obtain the optimized condition among the pulsed powers for thermal ablation. The results showed that for small source diameters (not larger than 4 mm), pulsed powers with high duties were more effective than continuous power. Although by increasing the source domain the fraction of damage caused by continuous power reached the damage caused by the pulsed powers, it affected the healthy tissues more (at least two times greater) than the pulsed powers. Pulsed powers with high duty (0.8 and 0.9) showed the optimized condition and the results have been explained based on the Arrhenius equation. Utilizing the pulsed powers for breast cancer treatment can potentially be an efficient approach for treating breast tumors due to requiring lower heating power and minimizing side effects to the healthy tissues.

ACS Style

Thanh-Luu Cao; Tuan-Anh Le; Yaser Hadadian; Jungwon Yoon. Theoretical Analysis for Using Pulsed Heating Power in Magnetic Hyperthermia Therapy of Breast Cancer. International Journal of Molecular Sciences 2021, 22, 8895 .

AMA Style

Thanh-Luu Cao, Tuan-Anh Le, Yaser Hadadian, Jungwon Yoon. Theoretical Analysis for Using Pulsed Heating Power in Magnetic Hyperthermia Therapy of Breast Cancer. International Journal of Molecular Sciences. 2021; 22 (16):8895.

Chicago/Turabian Style

Thanh-Luu Cao; Tuan-Anh Le; Yaser Hadadian; Jungwon Yoon. 2021. "Theoretical Analysis for Using Pulsed Heating Power in Magnetic Hyperthermia Therapy of Breast Cancer." International Journal of Molecular Sciences 22, no. 16: 8895.

Journal article
Published: 16 June 2021 in IEEE Access
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The high portability of vibrotactile feedback systems makes them suited to wearable applications, which improves their usability for rehabilitation applications encompassing a variety of environments and scenarios. A number of works have explored the relationship between arm movement and gait parameters such as gait variations and age on the arm swing. However, the inter-limb coupling scheme, i.e. the effects of the specific side (left or right) and direction (forward or backward) of arm swing variation on gait and balance parameters have not yet been evaluated. The study of these effects can enable us to devise arm movement based gait training protocols that may be beneficial for stroke survivors. We have developed a vibrotactile biofeedback system worn on the upper limb for post-stroke gait rehabilitation training. Using this system, we have carried out a study with ten healthy subjects and one stroke survivor to determine the effects of arm swing variation on gait and balance parameters. The healthy subject experiments revealed that increase in arm swing significantly increases the stride length while bringing about a statistically non-significant increase in the gait velocity. The study also revealed that the protocols involving variation of forward arm swing appear to have greater efficacy in modifying the gait symmetry ratio. Furthermore, the variations in arm swing and the resulting gait modifications do not produce any significant difference in the balance parameters. The results from the pilot test with one stroke survivor also show that increasing the arm swing increases the stride length and velocity. These findings suggest that arm swing variation using vibrotactile bracelets has effects on gait parameters that may be utilized for gait training of stroke survivors.

ACS Style

Hosu Lee; Amre Eizad; Yeongmi Kim; Yeongchae Park; Min-Kyun Oh; Jungwon Yoon. Use of Vibrotactile Bracelets to Study Effects of Arm Swing Variation on Overground Gait. IEEE Access 2021, 9, 90896 -90907.

AMA Style

Hosu Lee, Amre Eizad, Yeongmi Kim, Yeongchae Park, Min-Kyun Oh, Jungwon Yoon. Use of Vibrotactile Bracelets to Study Effects of Arm Swing Variation on Overground Gait. IEEE Access. 2021; 9 ():90896-90907.

Chicago/Turabian Style

Hosu Lee; Amre Eizad; Yeongmi Kim; Yeongchae Park; Min-Kyun Oh; Jungwon Yoon. 2021. "Use of Vibrotactile Bracelets to Study Effects of Arm Swing Variation on Overground Gait." IEEE Access 9, no. : 90896-90907.

Journal article
Published: 06 May 2021 in Applied Sciences
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To achieve an immersive virtual reality (VR) environment, omnidirectional treadmills (ODTs) allow users to perform locomotion in any direction. However, existing ODTs are heavy and complex, and operate at low speeds. This limits fast user motion and prevents natural interactions in real applications such as military training programs and interactive games. In this paper, we introduce a novel locomotion interface device with running capability, which uses an omnidirectional treadmill with a new power transmission mechanism and a locomotion controller that enables the user to make fast movements. As a result of the improved power transmission performance due to the simple and relatively lightweight structure, the proposed two-dimensional treadmill can generate a maximum speed of 3 m/s, with an acceleration of 3 m/s2. Moreover, through a pilot test with the proposed locomotion interface device, we verified that the fast directional changes during walking and running with the designed speed adaptation controller do not exceed the acceleration performance of the proposed system. Due to its wide range of movement speeds and acceleration capabilities, and lack of any motion constraints, the proposed locomotion interface device with a novel ODT can be used as a representative platform in various VR environments to enhance the immersive experience.

ACS Style

Sanghun Pyo; Hosu Lee; Jungwon Yoon. Development of a Novel Omnidirectional Treadmill-Based Locomotion Interface Device with Running Capability. Applied Sciences 2021, 11, 4223 .

AMA Style

Sanghun Pyo, Hosu Lee, Jungwon Yoon. Development of a Novel Omnidirectional Treadmill-Based Locomotion Interface Device with Running Capability. Applied Sciences. 2021; 11 (9):4223.

Chicago/Turabian Style

Sanghun Pyo; Hosu Lee; Jungwon Yoon. 2021. "Development of a Novel Omnidirectional Treadmill-Based Locomotion Interface Device with Running Capability." Applied Sciences 11, no. 9: 4223.

Journal article
Published: 23 April 2021 in Nanomaterials
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Multifunctional magnetic nanomaterials displaying high specific loss power (SLP) and high imaging sensitivity with good spatial resolution are highly desired in image-guided cancer therapy. Currently, commercial nanoparticles do not sufficiently provide such multifunctionality. For example, Resovist® has good image resolution but with a low SLP, whereas BNF® has a high SLP value with very low image resolution. In this study, hydrophilic magnesium iron [email protected] ammonium hydroxide nanoparticles were prepared in two steps. First, hydrophobic magnesium iron oxide nanoparticles were fabricated using a thermal decomposition technique, followed by coating with tetramethyl ammonium hydroxide. The synthesized nanoparticles were characterized using XRD, DLS, TEM, zeta potential, UV-Vis spectroscopy, and VSM. The hyperthermia and imaging properties of the prepared nanoparticles were investigated and compared to the commercial nanoparticles. One-dimensional magnetic particle imaging indicated the good imaging resolution of our nanoparticles. Under the application of a magnetic field of frequency 614.4 kHz and strength 9.5 kA/m, nanoparticles generated heat with an SLP of 216.18 W/g, which is much higher than that of BNF (14 W/g). Thus, the prepared nanoparticles show promise as a novel dual-functional magnetic nanomaterial, enabling both high performance for hyperthermia and imaging functionality for diagnostic and therapeutic processes.

ACS Style

Mohamed Darwish; Hohyeon Kim; Minh Bui; Tuan-Anh Le; Hwangjae Lee; Chiseon Ryu; Jae Lee; Jungwon Yoon. The Heating Efficiency and Imaging Performance of Magnesium Iron [email protected] Ammonium Hydroxide Nanoparticles for Biomedical Applications. Nanomaterials 2021, 11, 1096 .

AMA Style

Mohamed Darwish, Hohyeon Kim, Minh Bui, Tuan-Anh Le, Hwangjae Lee, Chiseon Ryu, Jae Lee, Jungwon Yoon. The Heating Efficiency and Imaging Performance of Magnesium Iron [email protected] Ammonium Hydroxide Nanoparticles for Biomedical Applications. Nanomaterials. 2021; 11 (5):1096.

Chicago/Turabian Style

Mohamed Darwish; Hohyeon Kim; Minh Bui; Tuan-Anh Le; Hwangjae Lee; Chiseon Ryu; Jae Lee; Jungwon Yoon. 2021. "The Heating Efficiency and Imaging Performance of Magnesium Iron [email protected] Ammonium Hydroxide Nanoparticles for Biomedical Applications." Nanomaterials 11, no. 5: 1096.

Journal article
Published: 01 December 2020 in IEEE/ASME Transactions on Mechatronics
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A magnetic drug-targeting (MDT) system featuring real-time imaging, guidance, and local heating is required for more precise drug targeting and minimization of side effects. In this paper, we present a novel electromagnetic navigation and heating system that not only guides and navigates magnetic nanoparticles (MNPs) with real-time imaging feedback, but also uses focused MNP heating to release drugs while monitoring the temperature. The magnetic field amplitude and magnetic gradient play key roles in our integrated system; we enhanced the gradient and field within a field of view (FOV) of 30 x 30 mm. Performance was examined via simulation employing COMSOL Multiphysics software, and verified experimentally. After optimization, the maximum gradients attained on the x and y axes are 4.15 and 2.23 T/m/μ0, respectively, for the electromagnetic actuator (EMA) mode, and 8.48 T/m/μ0 for the magnetic particle imaging (MPI) mode. The magnetic field amplitude for heating was 19.70 mT at 100 kHz. We then built a two-dimensional MNPs navigation/heating system to demonstrate the in vitro feasibility of our scheme; this afforded a 1-Hz navigation update rate during MNPs guidance in a Y-shaped channel, and locally heated MNPs with temperature monitoring.

ACS Style

Tuan-Anh Le; Minh Phu Bui; Jungwon Yoon. Optimal Design and Implementation of a Novel Two-Dimensional Electromagnetic Navigation System That Allows Focused Heating of Magnetic Nanoparticles. IEEE/ASME Transactions on Mechatronics 2020, 26, 551 -562.

AMA Style

Tuan-Anh Le, Minh Phu Bui, Jungwon Yoon. Optimal Design and Implementation of a Novel Two-Dimensional Electromagnetic Navigation System That Allows Focused Heating of Magnetic Nanoparticles. IEEE/ASME Transactions on Mechatronics. 2020; 26 (1):551-562.

Chicago/Turabian Style

Tuan-Anh Le; Minh Phu Bui; Jungwon Yoon. 2020. "Optimal Design and Implementation of a Novel Two-Dimensional Electromagnetic Navigation System That Allows Focused Heating of Magnetic Nanoparticles." IEEE/ASME Transactions on Mechatronics 26, no. 1: 551-562.

Journal article
Published: 24 November 2020 in IEEE Transactions on Industrial Electronics
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Magnetic nanoparticles (MNPs) exhibiting certain superparamagnetic properties are optimal in terms of drug delivery because they facilitate imaging and targeting of biological interactions at the cellular and molecular levels. In terms of monitoring, magnetic particle imaging (MPI) yields real-time MNPs position and concentration data, and guides MNPs to desired positions if an actuation function is available. Here, we describe a new, user-driven steering scheme for MNPs based on a virtual field free point (FFP). The scheme utilizes our current MPI system, with no need for additional hardware. The scheme facilitates interactive user manipulation with real-time imaging and MNPs actuation within the body. An FFP with four coils was used to model the resultant magnetic force and a virtual FFP to linearize that force with respect to the relative positions of the MNPs and the real FFP. Simulations and experiments confirmed that the direction and magnitude of the forces exerted on MNPs via manipulation of the virtual FFP were controllable. An intuitive guidance system featuring real-time MPI at 2 Hz and user-driven virtual FFP manipulation (via a mouse) was employed to show that MNPs trajectories can be controlled. Our MPI-based navigation platform allows the user to effectively guide MNPs using real-time visual feedback, facilitating targeted drug delivery.

ACS Style

Minh Phu Bui; Tuan-Anh Le; Jungwon Yoon. A Magnetic Particle Imaging-based Navigation Platform for Magnetic Nanoparticles using Interactive Manipulation of a Virtual Field Free Point to Ensure Targeted Drug Delivery. IEEE Transactions on Industrial Electronics 2020, PP, 1 -1.

AMA Style

Minh Phu Bui, Tuan-Anh Le, Jungwon Yoon. A Magnetic Particle Imaging-based Navigation Platform for Magnetic Nanoparticles using Interactive Manipulation of a Virtual Field Free Point to Ensure Targeted Drug Delivery. IEEE Transactions on Industrial Electronics. 2020; PP (99):1-1.

Chicago/Turabian Style

Minh Phu Bui; Tuan-Anh Le; Jungwon Yoon. 2020. "A Magnetic Particle Imaging-based Navigation Platform for Magnetic Nanoparticles using Interactive Manipulation of a Virtual Field Free Point to Ensure Targeted Drug Delivery." IEEE Transactions on Industrial Electronics PP, no. 99: 1-1.

Journal article
Published: 06 November 2020 in IEEE Access
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Physical therapy involving the use of varying types of seating surface and visual input is recommended for individuals suffering from trunk instability. Some robots have been developed to assist in such therapy protocols, but none of them fully constrains the user’s lower extremities to move with the seat, which is required to fully transfer the task of maintaining balance to the trunk. To fulfill this requirement, we have developed a robot that can provide a static, unstable or forced perturbation seating surface. The instability of seating surface is provided by having the robot follow movements in the user’s center of pressure (COP) and forced perturbations are provided by moving the surface according to an operator’s commands irrespective of the COP position. The system is also capable of providing visual feedback of the user’s COP. This paper presents a study conducted using this novel robot aimed at evaluating the effect of the different seat modes on the balance of healthy subjects under different visual conditions (blindfold, eyes open and visual feedback). Various COP and trunk movement parameters were observed and the results indicate that the system can elicit similar responses in the unstable mode as the conventional devices, showing that it may be used as a controllable alternative to such devices for the training and objective evaluation of stroke survivors. The results under perturbation conditions showed deviations from the generally held notions about the use of visual feedback. Thus, revealing the need for further studies on the implications of using visual feedback under perturbation conditions. The observation of effects similar to conventional systems that may be beneficial for stroke survivors and the system’s ability to help assess recovery progress show that the system holds promise for use as a trunk training and objective performance evaluation tool for stroke survivors.

ACS Style

Amre Eizad; Hosu Lee; Sanghun Pyo; Muhammad Raheel Afzal; Sung-Ki Lyu; Jungwon Yoon. A Novel Trunk Rehabilitation Robot Based Evaluation of Seated Balance Under Varying Seat Surface and Visual Conditions. IEEE Access 2020, 8, 204902 -204913.

AMA Style

Amre Eizad, Hosu Lee, Sanghun Pyo, Muhammad Raheel Afzal, Sung-Ki Lyu, Jungwon Yoon. A Novel Trunk Rehabilitation Robot Based Evaluation of Seated Balance Under Varying Seat Surface and Visual Conditions. IEEE Access. 2020; 8 (99):204902-204913.

Chicago/Turabian Style

Amre Eizad; Hosu Lee; Sanghun Pyo; Muhammad Raheel Afzal; Sung-Ki Lyu; Jungwon Yoon. 2020. "A Novel Trunk Rehabilitation Robot Based Evaluation of Seated Balance Under Varying Seat Surface and Visual Conditions." IEEE Access 8, no. 99: 204902-204913.

Journal article
Published: 20 August 2020 in IEEE Transactions on Biomedical Engineering
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Targeted drug delivery using magnetic particles (MPs) and external magnets for focusing them at the diseased regions, called magnetic drug targeting (MDT), is a next-generation therapeutic method that is being continually improved. However, most existing magnetic systems cannot focus MPs in the targeted region due to there not being enough magnetic capturing force and absence of schemes to generate localized high magnetic field at the wall of the target region. This paper suggests a novel scheme to utilize half of a static saddle potential energy configuration generated using four electromagnets that not only enhances the pushing magnetic forces but also simultaneously generates pushing and attracting forces in the desired direction to help focus spherical MPs on the wall of the target region. Furthermore, by changing amplitudes or directions of the currents, the focal point in the target region can be changed. Through extensive simulations and in vitro experiments, we demonstrate that half of a static saddle magnetic potential energy configuration can be successfully utilized to attract and focus MPs at the wall of a target region.

ACS Style

Tuan-Anh Le; Minh Phu Bui; Jungwon Yoon. Electromagnetic Actuation System for Focused Capturing of Magnetic Particles With a Half of Static Saddle Potential Energy Configuration. IEEE Transactions on Biomedical Engineering 2020, 68, 869 -880.

AMA Style

Tuan-Anh Le, Minh Phu Bui, Jungwon Yoon. Electromagnetic Actuation System for Focused Capturing of Magnetic Particles With a Half of Static Saddle Potential Energy Configuration. IEEE Transactions on Biomedical Engineering. 2020; 68 (3):869-880.

Chicago/Turabian Style

Tuan-Anh Le; Minh Phu Bui; Jungwon Yoon. 2020. "Electromagnetic Actuation System for Focused Capturing of Magnetic Particles With a Half of Static Saddle Potential Energy Configuration." IEEE Transactions on Biomedical Engineering 68, no. 3: 869-880.

Journal article
Published: 30 July 2020 in Journal of the Korean Society of Manufacturing Process Engineers
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ACS Style

Amre Eizad; Sanghun Pyo; Geonhyup Lee; Sung-Ki Lyu; Jungwon Yoon. Study on the Design and Analysis of a 4-DOF Robot for Trunk Rehabilitation. Journal of the Korean Society of Manufacturing Process Engineers 2020, 19, 41 -51.

AMA Style

Amre Eizad, Sanghun Pyo, Geonhyup Lee, Sung-Ki Lyu, Jungwon Yoon. Study on the Design and Analysis of a 4-DOF Robot for Trunk Rehabilitation. Journal of the Korean Society of Manufacturing Process Engineers. 2020; 19 (7):41-51.

Chicago/Turabian Style

Amre Eizad; Sanghun Pyo; Geonhyup Lee; Sung-Ki Lyu; Jungwon Yoon. 2020. "Study on the Design and Analysis of a 4-DOF Robot for Trunk Rehabilitation." Journal of the Korean Society of Manufacturing Process Engineers 19, no. 7: 41-51.

Journal article
Published: 21 May 2020 in Nanomaterials
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Magnetic ferrite nanoparticles (MFNs) with high heating efficiency are highly desirable for hyperthermia applications. As conventional MFNs usually show low heating efficiency with a lower specific loss power (SLP), extensive efforts to enhance the SLP of MFNs have been made by varying the particle compositions, sizes, and structures. In this study, we attempted to increase the SLP values by creating core-shell structures of MFNs. Accordingly, first we synthesized three different types of core ferrite nanoparticle of magnetite (mag), cobalt ferrite (cf) and zinc cobalt ferrite (zcf). Secondly, we synthesized eight bi-magnetic core-shell structured MFNs; [email protected] ([email protected], [email protected]), [email protected] ([email protected], [email protected]), [email protected] ([email protected], [email protected]), and [email protected] ([email protected], [email protected]), using a modified controlled co-precipitation process. SLP values of the prepared core-shell MFNs were investigated with respect to their compositions and core/shell dimensions while varying the applied magnetic field strength. Hyperthermia properties of the prepared core-shell MFNs were further compared to commercial magnetic nanoparticles under the safe limits of magnetic field parameters (

ACS Style

Mohamed S. A. Darwish; Hohyeon Kim; Hwangjae Lee; Chiseon Ryu; Jae Young Lee; Jungwon Yoon. Engineering Core-Shell Structures of Magnetic Ferrite Nanoparticles for High Hyperthermia Performance. Nanomaterials 2020, 10, 991 .

AMA Style

Mohamed S. A. Darwish, Hohyeon Kim, Hwangjae Lee, Chiseon Ryu, Jae Young Lee, Jungwon Yoon. Engineering Core-Shell Structures of Magnetic Ferrite Nanoparticles for High Hyperthermia Performance. Nanomaterials. 2020; 10 (5):991.

Chicago/Turabian Style

Mohamed S. A. Darwish; Hohyeon Kim; Hwangjae Lee; Chiseon Ryu; Jae Young Lee; Jungwon Yoon. 2020. "Engineering Core-Shell Structures of Magnetic Ferrite Nanoparticles for High Hyperthermia Performance." Nanomaterials 10, no. 5: 991.

Journal article
Published: 11 May 2020 in IEEE/ASME Transactions on Mechatronics
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In this paper, a novel lower extremity gait rehabilitation device with a single actuator is presented. The proposed device, Mech-Walker, utilizes the single Degree of Freedom (DOF) 8-bar Jansen's mechanism. The mechanism is synthesized to generate the ankle trajectory of human gait, relative to the hip, in terms of both position and time. Two mechanisms, one for each leg, are applied reciprocally and are mechanically synchronized to guarantee symmetric gait. A custom designed seat-type weight support system mounted over a commercially available treadmill is also introduced. It not only supports the user and the mechanisms but also links the mechanism's base to the subject's hip. This vertically movable-base allows ground contact proprioception for the user which is crucial in gait training. As this is a non-anthropomorphic design interacting with the leg only at hip and ankle via seat and footrest respectively, it does not need to be aligned with the subject's joints, which facilitates the donning and doffing of the device. Adjustability of mechanism to different users has also been considered to provide an effective training tool. A prototype is manufactured, and pilot study with a healthy subject is conducted. Due to ease of control, cost-effectiveness and high intrinsic safety, the proposed system potentially offers a novel tool for gait training.

ACS Style

Mohammad Reza Haghjoo; Hosu Lee; Muhammad Raheel Afzal; Amre Eizad; Jungwon Yoon. Mech-Walker:A Novel Single-DOF Linkage Device With Movable Frame for Gait Rehabilitation. IEEE/ASME Transactions on Mechatronics 2020, 26, 13 -23.

AMA Style

Mohammad Reza Haghjoo, Hosu Lee, Muhammad Raheel Afzal, Amre Eizad, Jungwon Yoon. Mech-Walker:A Novel Single-DOF Linkage Device With Movable Frame for Gait Rehabilitation. IEEE/ASME Transactions on Mechatronics. 2020; 26 (1):13-23.

Chicago/Turabian Style

Mohammad Reza Haghjoo; Hosu Lee; Muhammad Raheel Afzal; Amre Eizad; Jungwon Yoon. 2020. "Mech-Walker:A Novel Single-DOF Linkage Device With Movable Frame for Gait Rehabilitation." IEEE/ASME Transactions on Mechatronics 26, no. 1: 13-23.

Journal article
Published: 12 April 2020 in Catalysts
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One of the challenges in the preparation of poly(methyl methacrylate) (PMMA) is to develop new catalytic systems with improved efficiency. A hybrid iron oxide silver catalyst holds promise in solving this issue. Catalysts were prepared at room temperature by a two-step technique. First, iron oxide nanoparticles were prepared by the reduction of FeCl3 using sodium borohydride (NaBH4) at room temperature. Second, magnetic nanoparticles doped with a series of Ag nanoparticles (Ag, Ag/3 –amino propyltriethoxysilane (APTES) and Ag/poly(ethyleneimine) (PEI)). The prepared catalysts were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), and Fourier-transform infrared spectroscopy (FTIR). The catalytic activity of Fe, Ag/Fe, PEI–Ag/Fe, and APTES–Ag/Fe in methyl methacrylate (MMA) polymerization was investigated in the presence of O2, N2, NaHSO3, and benzoyl peroxide in bulk or solution conditions. The produced polymer was characterized by gel permeation chromatography (GPC) and proton nuclear magnetic resonance spectroscopy (1HNMR). The structures of PEI–Ag/Fe and APTES–Ag/Fe are assumed. The conversion efficiency was 100%, 100%, 97.6%, and 99.1% using Fe, Ag/Fe, PEI–Ag/Fe, and APTES–Ag/Fe catalysts at the optimum conditions, respectively. Hybrid iron oxide silver nanoparticles are promising catalysts for PMMA preparation.

ACS Style

Sanaa Solyman; Mohamed S.A. Darwish; Jungwon Yoon. Catalytic Activity of Hybrid Iron Oxide Silver Nanoparticles in Methyl Methacrylate Polymerization. Catalysts 2020, 10, 422 .

AMA Style

Sanaa Solyman, Mohamed S.A. Darwish, Jungwon Yoon. Catalytic Activity of Hybrid Iron Oxide Silver Nanoparticles in Methyl Methacrylate Polymerization. Catalysts. 2020; 10 (4):422.

Chicago/Turabian Style

Sanaa Solyman; Mohamed S.A. Darwish; Jungwon Yoon. 2020. "Catalytic Activity of Hybrid Iron Oxide Silver Nanoparticles in Methyl Methacrylate Polymerization." Catalysts 10, no. 4: 422.

Journal article
Published: 13 February 2020 in IEEE Access
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The aim of gait rehabilitation is to achieve independent ambulation. Somatosensory augmentation with external haptic sources can improve the subject’s ability to walk or stand. This paper presents the development and evaluation of a robotic system prototype that delivers haptic forces to aid overground gait rehabilitation. This portable system is based on a compact, mobile robot that is equipped with force and LIDAR sensors. The robot is flexibly linked to the user, which allows the force interaction between the user and machine to be halted when desired. During operation, the system can dynamically transition between modes in which force is applied or distance is maintained to emulate the experience of a human walking a dog on a leash. The haptic feedback from our system was evaluated in a pilot study that involved six young, healthy subjects and one individual recovering from a hemiparetic stroke. The study comprised independent and device-assisted walking trials. When using the device, the subjects walked continuously as it transitioned between distance and force modes. Gait speed and step length increased when force was applied and decreased as the force was removed. The improvements exhibited by an individual suffering from stroke were similar to those exhibited by healthy subjects. The application of haptic forces has a high potential for improving the efficiency of overground gait training with simple interactions.

ACS Style

Hosu Lee; Amre Eizad; Sanghun Pyo; Muhammad Raheel Afzal; Min-Kyun Oh; Yun-Jeong Jang; Jungwon Yoon. Development of a Robotic Companion to Provide Haptic Force Interaction for Overground Gait Rehabilitation. IEEE Access 2020, 8, 34888 -34899.

AMA Style

Hosu Lee, Amre Eizad, Sanghun Pyo, Muhammad Raheel Afzal, Min-Kyun Oh, Yun-Jeong Jang, Jungwon Yoon. Development of a Robotic Companion to Provide Haptic Force Interaction for Overground Gait Rehabilitation. IEEE Access. 2020; 8 (99):34888-34899.

Chicago/Turabian Style

Hosu Lee; Amre Eizad; Sanghun Pyo; Muhammad Raheel Afzal; Min-Kyun Oh; Yun-Jeong Jang; Jungwon Yoon. 2020. "Development of a Robotic Companion to Provide Haptic Force Interaction for Overground Gait Rehabilitation." IEEE Access 8, no. 99: 34888-34899.

Research paper
Published: 03 February 2020 in Journal of Micro-Bio Robotics
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Magnetic drug targeting has emerged as a promising approach for enhancing the efficiency of drug delivery. Recent developments in real-time monitoring techniques have enabled the guidance of magnetic nanoparticles (MNPs) in the vascular network. Despite recent developments in magnetic navigation, no comprehensive strategy for swarm of nanoparticles steering under fluid flow exists. This paper introduces a strategy for MNPs steering in a vascular network under fluid flow. In the proposed scheme, the swarm of nanoparticles are initially guided to an area that guarantees their successful guidance towards a desired direction (called safe zone) using an asymmetrical field function to handle swarm of nanoparticles. Then, a transporter field function is used to transfer the particles between the safe zones, and finally a sustainer field function is used to keep the particles within the safe zone. A steering algorithm is proposed to enhance the targeting performance in the multi-bifurcation vessel. Utilizing the proposed concept, a high success rate for targeting is achieved in simulations, which demonstrates the potential and limitations of swarm of nanoparticles steering under fluid flow.

ACS Style

Ali Kafash Hoshiar; Tuan-Anh Le; Pietro Valdastri; Jungwon Yoon. Swarm of magnetic nanoparticles steering in multi-bifurcation vessels under fluid flow. Journal of Micro-Bio Robotics 2020, 16, 137 -145.

AMA Style

Ali Kafash Hoshiar, Tuan-Anh Le, Pietro Valdastri, Jungwon Yoon. Swarm of magnetic nanoparticles steering in multi-bifurcation vessels under fluid flow. Journal of Micro-Bio Robotics. 2020; 16 (2):137-145.

Chicago/Turabian Style

Ali Kafash Hoshiar; Tuan-Anh Le; Pietro Valdastri; Jungwon Yoon. 2020. "Swarm of magnetic nanoparticles steering in multi-bifurcation vessels under fluid flow." Journal of Micro-Bio Robotics 16, no. 2: 137-145.

Journal article
Published: 21 January 2020 in IEEE Magnetics Letters
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Magnetic particle imaging (MPI) is a fast and sensitive technique for imaging of magnetic nanoparticles (MNPs) concentrations. MPI directly measures and maps the particle concentration over a measured spatial position. Functional MPI (fMPI) is a specific application of MPI that aims to detect the change of cerebral blood volume (CBV) through imaging. Assuming that the concentration of MNPs in the CBV is uniform, the resultant concentration of MNPs can indicate the CBV changes. Magnetic particle spectroscopy (MPS) is basically a zero-dimensional MPI scanner, which can be used to conduct spectroscopic studies and fMPI. In this paper, we suggest a MPS for fMPI with a bore size of 50 mm compatible with rat head dimensions. The system utilizes a 0.015 T magnetic field at a frequency of 29.5 kHz and uses an integrated method to measure the small iron component of magnetic particles. Based on the integrated output signal, the proposed MPS consisting of an excitation coil and a gradiometer coil with three parts: a receive coil, a cancellation coil, and a calibration coil, can detect down to 25 ng of Fe. The suggested MPS has demonstrated the achievement of sensitivity that is feasible for fMPI.

ACS Style

Minh Phu Bui; Tuan-Anh Le; Jungwon Yoon. Development of Rat-Scale Magnetic Particle Spectroscopy for Functional Magnetic Particle Imaging. IEEE Magnetics Letters 2020, 11, 1 -5.

AMA Style

Minh Phu Bui, Tuan-Anh Le, Jungwon Yoon. Development of Rat-Scale Magnetic Particle Spectroscopy for Functional Magnetic Particle Imaging. IEEE Magnetics Letters. 2020; 11 (99):1-5.

Chicago/Turabian Style

Minh Phu Bui; Tuan-Anh Le; Jungwon Yoon. 2020. "Development of Rat-Scale Magnetic Particle Spectroscopy for Functional Magnetic Particle Imaging." IEEE Magnetics Letters 11, no. 99: 1-5.

Journal article
Published: 01 January 2020 in IEEE Access
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ACS Style

Myungjin Park; Tuan-Anh Le; Amre Eizad; Jungwon Yoon. A Novel Shared Guidance Scheme for Intelligent Haptic Interaction Based Swarm Control of Magnetic Nanoparticles in Blood Vessels. IEEE Access 2020, 8, 106714 -106725.

AMA Style

Myungjin Park, Tuan-Anh Le, Amre Eizad, Jungwon Yoon. A Novel Shared Guidance Scheme for Intelligent Haptic Interaction Based Swarm Control of Magnetic Nanoparticles in Blood Vessels. IEEE Access. 2020; 8 ():106714-106725.

Chicago/Turabian Style

Myungjin Park; Tuan-Anh Le; Amre Eizad; Jungwon Yoon. 2020. "A Novel Shared Guidance Scheme for Intelligent Haptic Interaction Based Swarm Control of Magnetic Nanoparticles in Blood Vessels." IEEE Access 8, no. : 106714-106725.

Journal article
Published: 16 August 2019 in Nanomaterials
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Magnetic nanoparticles (MNPs) that exhibit high specific loss power (SLP) at lower metal content are highly desirable for hyperthermia applications. The conventional co-precipitation process has been widely employed for the synthesis of magnetic nanoparticles. However, their hyperthermia performance is often insufficient, which is considered as the main challenge to the development of practicable cancer treatments. In particular, ferrite MNPs have unique properties, such as a strong magnetocrystalline anisotropy, high coercivity, and moderate saturation magnetization, however their hyperthermia performance needs to be further improved. In this study, cobalt ferrite (CoFe2O4) and zinc cobalt ferrite nanoparticles (ZnCoFe2O4) were prepared to achieve high SLP values by modifying the conventional co-precipitation method. Our modified method, which allows for precursor material compositions (molar ratio of Fe+3:Fe+2:Co+2/Zn+2 of 3:2:1), is a simple, environmentally friendly, and low temperature process carried out in air at a maximum temperature of 60 °C, without the need for oxidizing or coating agents. The particles produced were characterized using multiple techniques, such as X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV–Vis spectroscopy), and a vibrating sample magnetometer (VSM). SLP values of the prepared nanoparticles were carefully evaluated as a function of time, magnetic field strength (30, 40, and 50 kA m−1), and the viscosity of the medium (water and glycerol), and compared to commercial magnetic nanoparticle materials under the same conditions. The cytotoxicity of the prepared nanoparticles by in vitro culture with NIH-3T3 fibroblasts exhibited good cytocompatibility up to 0.5 mg/mL. The safety limit of magnetic field parameters for SLP was tested. It did not exceed the 5 × 109 Am−1 s−1 threshold. A saturation temperature of 45 °C could be achieved. These nanoparticles, with minimal metal content, can ideally be used for in vivo hyperthermia applications, such as cancer treatments.

ACS Style

Mohamed S. A. Darwish; Hohyeon Kim; Jae Young Lee; Chiseon Ryu; Jungwon Yoon. Synthesis of Magnetic Ferrite Nanoparticles with High Hyperthermia Performance via a Controlled Co-Precipitation Method. Nanomaterials 2019, 9, 1176 .

AMA Style

Mohamed S. A. Darwish, Hohyeon Kim, Jae Young Lee, Chiseon Ryu, Jungwon Yoon. Synthesis of Magnetic Ferrite Nanoparticles with High Hyperthermia Performance via a Controlled Co-Precipitation Method. Nanomaterials. 2019; 9 (8):1176.

Chicago/Turabian Style

Mohamed S. A. Darwish; Hohyeon Kim; Jae Young Lee; Chiseon Ryu; Jungwon Yoon. 2019. "Synthesis of Magnetic Ferrite Nanoparticles with High Hyperthermia Performance via a Controlled Co-Precipitation Method." Nanomaterials 9, no. 8: 1176.

Articles
Published: 02 July 2019 in Journal of Dispersion Science and Technology
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One of the main challenges in the reduction of the electromagnetic wave is to develop lightweight absorber material with a wide absorption frequency. Hence, developing shielding materials that could shield electromagnetic radiation to prevent interference is highly desired for protection. The combination between the unique properties of polyamide (PA6) with free surfactant magnetite nanoparticle as core/shell nanofibers (PA6 @ Fe3O4) provides a promising low-cost, environmentally-friendly and electromagnetic shielding properties. Free surfactant magnetite nanoparticles (39 ± 3.5 nm average size) were prepared by the co-precipitation process and incorporated directly into the polyamide solution before the electrospinning technique. The mean average size of the prepared magnetite nanoparticles is compared based on X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM). The morphology, thermal stability and magnetic behavior of the resultant magnetite nanofibers (150 ± 25 nm average size) were investigated using high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM), respectively. Shielding effectiveness for magnetite polyamide core/shell nanofibers was measured at frequency 30 MHz–1.5 GHz. The results showed that core/shell nanofibers provide not only well-dispersed magnetite nanoparticles in the polyamide matrix but also controllable sized nanofibers with high magnetization. In addition, even with low magnetite loading of 1.7%, the fabricated nanofiber shows high thermal stability with good performance as electromagnetic shielding nanofiber. Therefore, magnetite polyamide core/shell nanofiber could be considered as a promising material for shielding application.

ACS Style

Mohamed S. A. Darwish; Ahmed Bakry; Laila M. Al-Harbi; Manal M. Khowdiary; A. A. El-Henawy; Jungwon Yoon. Core/shell PA6 @ Fe3O4 nanofibers: Magnetic and shielding behavior. Journal of Dispersion Science and Technology 2019, 41, 1711 -1719.

AMA Style

Mohamed S. A. Darwish, Ahmed Bakry, Laila M. Al-Harbi, Manal M. Khowdiary, A. A. El-Henawy, Jungwon Yoon. Core/shell PA6 @ Fe3O4 nanofibers: Magnetic and shielding behavior. Journal of Dispersion Science and Technology. 2019; 41 (11):1711-1719.

Chicago/Turabian Style

Mohamed S. A. Darwish; Ahmed Bakry; Laila M. Al-Harbi; Manal M. Khowdiary; A. A. El-Henawy; Jungwon Yoon. 2019. "Core/shell PA6 @ Fe3O4 nanofibers: Magnetic and shielding behavior." Journal of Dispersion Science and Technology 41, no. 11: 1711-1719.

Journal article
Published: 24 June 2019 in IEEE Transactions on Neural Systems and Rehabilitation Engineering
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Variations in biofeedback coding schemes for postural control, in recent research, have shown significant differences in performance outcomes due to variations in coding schemes. However, the application of vibrotactile biofeedback coding schemes to gait symmetry training is not well explored. In this paper, we devised various vibrotactile biofeedback modes and identified their efficacy during gait symmetry training of individuals suffering from hemiparesis due to stroke. These modes are composed of variations in vibration type (on-time or intensity), and relation type (proportional or inversely-proportional) with the error in symmetry ratio. Eight individuals with stroke participated in walking trials. From dependent t-tests on the collected data, we found improved achievement of temporal gait symmetry while utilizing all the provided biofeedback modes compared to no biofeedback (P<0.001). Furthermore, two-way repeated measures ANOVA revealed statistically significant difference in symmetry ratio for main effect of vibration type (P-value = 0.016, partial eta squared = 0.585). The participants performed better with modes of biofeedback with varying vibration on-times. Furthermore, participants showed better performance when the biofeedback varied proportionally with the error. These findings suggest that biofeedback coding schemes may have a significant effect on the performance of gait training.

ACS Style

Muhammad Raheel Afzal; Hosu Lee; Amre Eizad; Chang Han Lee; Min-Kyun Oh; Jungwon Yoon. Effects of Vibrotactile Biofeedback Coding Schemes on Gait Symmetry Training of Individuals With Stroke. IEEE Transactions on Neural Systems and Rehabilitation Engineering 2019, 27, 1617 -1625.

AMA Style

Muhammad Raheel Afzal, Hosu Lee, Amre Eizad, Chang Han Lee, Min-Kyun Oh, Jungwon Yoon. Effects of Vibrotactile Biofeedback Coding Schemes on Gait Symmetry Training of Individuals With Stroke. IEEE Transactions on Neural Systems and Rehabilitation Engineering. 2019; 27 (8):1617-1625.

Chicago/Turabian Style

Muhammad Raheel Afzal; Hosu Lee; Amre Eizad; Chang Han Lee; Min-Kyun Oh; Jungwon Yoon. 2019. "Effects of Vibrotactile Biofeedback Coding Schemes on Gait Symmetry Training of Individuals With Stroke." IEEE Transactions on Neural Systems and Rehabilitation Engineering 27, no. 8: 1617-1625.

Journal article
Published: 12 June 2019 in International Journal of Molecular Sciences
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A wireless magnetothermal stimulation (WMS) is suggested as a fast, tetherless, and implanted device-free stimulation method using low-radio frequency (100 kHz to 1 MHz) alternating magnetic fields (AMF). As magnetic nanoparticles (MNPs) can transduce alternating magnetic fields into heat, they are targeted to a region of the brain expressing the temperature-sensitive ion channel (TRPV1). The local temperature of the targeted area is increased up to 44 °C to open the TRPV1 channels and cause an influx of Ca2+ sensitive promoter, which can activate individual neurons inside the brain. The WMS has initially succeeded in showing the potential of thermomagnetics for the remote control of neural cell activity with MNPs that are internally targeted to the brain. In this paper, by using the steady-state temperature rise defined by Fourier’s law, the bio-heat equation, and COMSOL Multiphysics software, we investigate most of the basic parameters such as the specific loss power (SLP) of MNPs, the injection volume of magnetic fluid, stimulation and cooling times, and cytotoxic effects at high temperatures (43–44 °C) to provide a realizable design guideline for WMS.

ACS Style

Tuan-Anh Le; Minh Phu Bui; Jungwon Yoon. Theoretical Analysis for Wireless Magnetothermal Deep Brain Stimulation Using Commercial Nanoparticles. International Journal of Molecular Sciences 2019, 20, 2873 .

AMA Style

Tuan-Anh Le, Minh Phu Bui, Jungwon Yoon. Theoretical Analysis for Wireless Magnetothermal Deep Brain Stimulation Using Commercial Nanoparticles. International Journal of Molecular Sciences. 2019; 20 (12):2873.

Chicago/Turabian Style

Tuan-Anh Le; Minh Phu Bui; Jungwon Yoon. 2019. "Theoretical Analysis for Wireless Magnetothermal Deep Brain Stimulation Using Commercial Nanoparticles." International Journal of Molecular Sciences 20, no. 12: 2873.