Jun Ohta | Nara Institute of Science and Technology (NAIST) (original) (raw)
Papers by Jun Ohta
![Research paper thumbnail of [Invited Paper] Near-infrared Colorized Imaging Technologies and Their Fundus Camera Applications](https://attachments.academia-assets.com/118375643/thumbnails/1.jpg)
](ITE Transactions on Media Technology and Applications
ITE Technical Report; ITE Tech. Rep., May 26, 2014
Japanese Journal of Applied Physics, 1983
Liquid phase epitaxy of Ga x In1-x P on (100)-oriented GaAs and GaAs0.8P0.2 substrates has been s... more Liquid phase epitaxy of Ga x In1-x P on (100)-oriented GaAs and GaAs0.8P0.2 substrates has been studied. Results indicate that the solidus compositions of Ga x In1-x P on both substrates tend to be “locked” near the lattice matching composition. This “composition pulling” effect is shown to be consistent with a model that takes account of the contribution of lattice mismatch strain energy.
Japanese Journal of Applied Physics, 2006
Abstract An image sensor has limited dynamic range while the human eye has a logarithmic response... more Abstract An image sensor has limited dynamic range while the human eye has a logarithmic response over a wide range of light intensity. Although the sensor gain can be set high to identify details in darker areas on an image, this high gain results in saturation in brighter ...
Japanese Journal of Applied Physics, 1982
Liquid Phase Epitaxy (LPE) of Ga x In1-x P on (100)- and (111)B-oriented GaAs substrates has been... more Liquid Phase Epitaxy (LPE) of Ga x In1-x P on (100)- and (111)B-oriented GaAs substrates has been studied at the growth temperature of 735°C. The results indicate that the Ga distribution coefficient, growth rate and luminescence half-widths depend significantly on the substrate orientation. These types of behavior are qualitatively similar to those reported earlier for the growth of Ga x In1-x As on InP.
AIP Advances
Dopamine (DA) is the most important neurotransmitter involved in motor control. Abnormalities in ... more Dopamine (DA) is the most important neurotransmitter involved in motor control. Abnormalities in neurotransmitter levels may indicate brain disorders, such as Parkinson’s disease and depression. Herein, electrochemical sensors containing metal oxide nanoparticles were fabricated for detecting DA. Specifically, iron oxide nanoparticles were applied onto a flexible polyimide substrate to obtain a flexible microelectrode and their DA detection performance was evaluated in vitro and in vivo. The electrochemical performance of the fabricated sensor was evaluated via fast-scan cyclic voltammetry conducted in a DA solution at concentrations between 0 and 50 nM. The peak current corresponding to the oxidation reaction of the Fe2O3-modified microelectrode for DA was observed at an applied potential of 0.49 V. The modified microelectrode exhibited a DA response with a high sensitivity of 34.14 nA/ μm2 nM and a low limit of detection of 8.76 nM. In vivo experiments were performed using a freel...
International Journal of Molecular Sciences, 2022
Dopamine (DA) is the key regulator of reward behavior. The DA neurons in the ventral tegmental ar... more Dopamine (DA) is the key regulator of reward behavior. The DA neurons in the ventral tegmental area (VTA) and their projection areas, which include the prefrontal cortex (PFC), nucleus accumbens (NAc), and amygdala, play a primary role in the process of reward-driven behavior induced by the drugs of addiction, including nicotine and alcohol. In our previous study, we developed a novel platform consisting of micro-LED array devices to stimulate a large area of the brain of rats and monkeys with photo-stimulation and a microdialysis probe to estimate the DA release in the PFC. Our results suggested that the platform was able to detect the increased level of dopamine in the PFC in response to the photo-stimulation of both the PFC and VTA. In this study, we used this platform to photo-stimulate the VTA neurons in both ChrimsonR-expressing (non-specific) wild and dopamine transporter (DAT)-Cre (dopamine specific) mice, and measured the dopamine release in the nucleus accumbens shell (NAc...
IEEE Transactions on Circuits and Systems I: Regular Papers, 2020
Extended Abstracts of the 2010 International Conference on Solid State Devices and Materials, 2010
The Journal of The Institute of Image Information and Television Engineers, 2011
![Research paper thumbnail of [Paper] Demonstrations of Polarization Imaging Capability and Novel Functionality of Polarization-Analyzing CMOS Image Sensor with 65 nm Standard CMOS Process](https://attachments.academia-assets.com/99655958/thumbnails/1.jpg)
](ITE Transactions on Media Technology and Applications, 2014
2009 IEEE Biomedical Circuits and Systems Conference, 2009
Abstract A CMOS-based multisite microfluid ejection device was fabricated and demonstrated. Our a... more Abstract A CMOS-based multisite microfluid ejection device was fabricated and demonstrated. Our aim is to fabricate the device as a chemical stimulator for neuron cells at multiple sites by the local release of chemical compounds to mimic synaptic functions artificially. An array of micro-pumps was fabricated on the CMOS chip. Microfluid ejection was performed by actuation of a deformable silicone membrane. We measured the membrane displacement to characterize the performance of the micropump. Using this ...
Biomedical Optics Express, 2015
2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR), 2013
ABSTRACT CMOS-based bio-implantable optoelectronic devices for biomedical applications are presen... more ABSTRACT CMOS-based bio-implantable optoelectronic devices for biomedical applications are presented. Designs, functionalities of implantable on-chip brain imaging devices, optical stimulators for optogenetics and CMOS-based flexible neural stimulators for retinal prosthesis are described.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
We have developed a multimodal CMOS sensing device to detect fluorescence image and electrical po... more We have developed a multimodal CMOS sensing device to detect fluorescence image and electrical potential for neural activities in a mouse deep brain. The device consists of CMOS image sensor with on-chip electrodes and excitation light sources, all of which are integrated on a polyimide substrate. The novel feature of this device is its embedded on-chip electrodes which are partially transmit incident light so that the whole image can be acquired by the sensor. We have demonstrated the CMOS sensor device successfully operates in hippocampus area of an anesthetized mouse.
Biomedical Optics Express, 2014
ITE Transactions on Media Technology and Applications
ITE Technical Report; ITE Tech. Rep., May 26, 2014
Japanese Journal of Applied Physics, 1983
Liquid phase epitaxy of Ga x In1-x P on (100)-oriented GaAs and GaAs0.8P0.2 substrates has been s... more Liquid phase epitaxy of Ga x In1-x P on (100)-oriented GaAs and GaAs0.8P0.2 substrates has been studied. Results indicate that the solidus compositions of Ga x In1-x P on both substrates tend to be “locked” near the lattice matching composition. This “composition pulling” effect is shown to be consistent with a model that takes account of the contribution of lattice mismatch strain energy.
Japanese Journal of Applied Physics, 2006
Abstract An image sensor has limited dynamic range while the human eye has a logarithmic response... more Abstract An image sensor has limited dynamic range while the human eye has a logarithmic response over a wide range of light intensity. Although the sensor gain can be set high to identify details in darker areas on an image, this high gain results in saturation in brighter ...
Japanese Journal of Applied Physics, 1982
Liquid Phase Epitaxy (LPE) of Ga x In1-x P on (100)- and (111)B-oriented GaAs substrates has been... more Liquid Phase Epitaxy (LPE) of Ga x In1-x P on (100)- and (111)B-oriented GaAs substrates has been studied at the growth temperature of 735°C. The results indicate that the Ga distribution coefficient, growth rate and luminescence half-widths depend significantly on the substrate orientation. These types of behavior are qualitatively similar to those reported earlier for the growth of Ga x In1-x As on InP.
AIP Advances
Dopamine (DA) is the most important neurotransmitter involved in motor control. Abnormalities in ... more Dopamine (DA) is the most important neurotransmitter involved in motor control. Abnormalities in neurotransmitter levels may indicate brain disorders, such as Parkinson’s disease and depression. Herein, electrochemical sensors containing metal oxide nanoparticles were fabricated for detecting DA. Specifically, iron oxide nanoparticles were applied onto a flexible polyimide substrate to obtain a flexible microelectrode and their DA detection performance was evaluated in vitro and in vivo. The electrochemical performance of the fabricated sensor was evaluated via fast-scan cyclic voltammetry conducted in a DA solution at concentrations between 0 and 50 nM. The peak current corresponding to the oxidation reaction of the Fe2O3-modified microelectrode for DA was observed at an applied potential of 0.49 V. The modified microelectrode exhibited a DA response with a high sensitivity of 34.14 nA/ μm2 nM and a low limit of detection of 8.76 nM. In vivo experiments were performed using a freel...
International Journal of Molecular Sciences, 2022
Dopamine (DA) is the key regulator of reward behavior. The DA neurons in the ventral tegmental ar... more Dopamine (DA) is the key regulator of reward behavior. The DA neurons in the ventral tegmental area (VTA) and their projection areas, which include the prefrontal cortex (PFC), nucleus accumbens (NAc), and amygdala, play a primary role in the process of reward-driven behavior induced by the drugs of addiction, including nicotine and alcohol. In our previous study, we developed a novel platform consisting of micro-LED array devices to stimulate a large area of the brain of rats and monkeys with photo-stimulation and a microdialysis probe to estimate the DA release in the PFC. Our results suggested that the platform was able to detect the increased level of dopamine in the PFC in response to the photo-stimulation of both the PFC and VTA. In this study, we used this platform to photo-stimulate the VTA neurons in both ChrimsonR-expressing (non-specific) wild and dopamine transporter (DAT)-Cre (dopamine specific) mice, and measured the dopamine release in the nucleus accumbens shell (NAc...
IEEE Transactions on Circuits and Systems I: Regular Papers, 2020
Extended Abstracts of the 2010 International Conference on Solid State Devices and Materials, 2010
The Journal of The Institute of Image Information and Television Engineers, 2011
ITE Transactions on Media Technology and Applications, 2014
2009 IEEE Biomedical Circuits and Systems Conference, 2009
Abstract A CMOS-based multisite microfluid ejection device was fabricated and demonstrated. Our a... more Abstract A CMOS-based multisite microfluid ejection device was fabricated and demonstrated. Our aim is to fabricate the device as a chemical stimulator for neuron cells at multiple sites by the local release of chemical compounds to mimic synaptic functions artificially. An array of micro-pumps was fabricated on the CMOS chip. Microfluid ejection was performed by actuation of a deformable silicone membrane. We measured the membrane displacement to characterize the performance of the micropump. Using this ...
Biomedical Optics Express, 2015
2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR), 2013
ABSTRACT CMOS-based bio-implantable optoelectronic devices for biomedical applications are presen... more ABSTRACT CMOS-based bio-implantable optoelectronic devices for biomedical applications are presented. Designs, functionalities of implantable on-chip brain imaging devices, optical stimulators for optogenetics and CMOS-based flexible neural stimulators for retinal prosthesis are described.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009
We have developed a multimodal CMOS sensing device to detect fluorescence image and electrical po... more We have developed a multimodal CMOS sensing device to detect fluorescence image and electrical potential for neural activities in a mouse deep brain. The device consists of CMOS image sensor with on-chip electrodes and excitation light sources, all of which are integrated on a polyimide substrate. The novel feature of this device is its embedded on-chip electrodes which are partially transmit incident light so that the whole image can be acquired by the sensor. We have demonstrated the CMOS sensor device successfully operates in hippocampus area of an anesthetized mouse.
Biomedical Optics Express, 2014