京都大学 / 新制・課程博士 / 博士(理学) / 甲第24180号 / 理博第4871号 / 新制||理||1697(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 寺西 利治, 教授 島川 祐一, 教授 倉田 博基 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

The purpose of this study was to determine if NO blood concentrations increased acutely following an 8-week course of pulsed infrared light therapy (PILT) which could be linked to an improvement in peripheral protective sensation (PPS) in patients who have profound chronic diabetic peripheral neuropathy. A total of 22 subjects with the diagnosis of type 1 (N = 2) or type 2 (N = 20) diabetes participated in the study. PILT was administered to one foot chosen at random with the other foot serving as a within-subject control (no treatment). Patients underwent 24 treatments (3 times/week, for 8 weeks) for 30 min per treatment. Venous blood samples were taken during the last 5 min of treatment from veins in the dorsum of the control and experimental feet and were later analyzed for NO concentration. Contrary to the popular supposition, PILT treatments actually resulted in a significantly (P < 0.05) decreased concentration of NO. Additionally, there were no significant differences between the treated and untreated feet. Since in individuals where PILT has significantly improved PPS, PILT did not stimulate an increased NO content in the blood, it appears that infrared light improves peripheral protective sensation in patients by a mechanism other than an increased NO production.

Pulsed infrared light therapy (PILT) has been shown to increase peripheral sensation in diabetic patients with diabetic peripheral neuropathy (DPN). However, most studies last for very short periods, with the subjects receiving only 6-20 treatments. The purpose of this study was to evaluate the effectiveness of an eight-week course of PILT in reversing long-standing, profound DPN in patients with type 1 and type 2 diabetes. Twenty-two subjects with a diagnosis of type 1 (n=2) or type 2 (n=20) diabetes participated in the study. PILT was administered to one foot chosen at random with the other foot serving as a within-subject control (no treatment). Patients underwent 24 treatments (3 times/week, for eight weeks) for 30 min per treatment. Changes in peripheral protective sensation (PPS) were measured using Semmes-Weinstein monofilaments (SWM) ranging from 3.7 to 6.48. PILT improved PPS even in patients with long-standing chronic neuropathies whose initial pre-study sensation was not measurable with a 200-g SWM. PILT significantly improves PPS. While the exact mechanism of action is not understood, infrared light may improve peripheral neuropathies by improving foot perfusion by stimulating nitric oxide production.

Optoelectronic devices operating in the mid-wave (3-5 Μm) and long-wave (8-12 Μm) infrared (IR) regions of the electromagnetic spectrum are of a great interest for academic and industrial applications. Due to the lack of atmospheric absorption, devices operating within these spectral bands are particularly useful for spectroscopy, imaging, and dynamic scene projection. Advanced IR imaging systems have created an intense need for laboratory-based infrared scene projector (IRSP) systems which can be used for accurate simulation of real-world phenomena occurring in the IR. These IRSP systems allow for reliable, reproducible, safe, and cost-effective calibration of IR detector arrays. The current state-of-the-art technology utilized for the emitter source of IRSP systems is thermal pixel arrays (TPAs) which are based on thin film resistor technology. Thermal pixel array technology has fundamental limitations related to response time and maximum simulated apparent temperature, making them unsuitable for emulation of very hot (> 700 K) and rapidly evolving scenes. Additionally, there exists a need for dual wavelength emitter arrays for IRSP systems dedicated to calibration of dual wavelength detector arrays. This need is currently met by combining the spectral output from two separate IRSP systems. This configuration requires precise alignment of the output from both systems and results in the maximum radiance being limited to approximately half that of the capability of a given emitter array due to the optics used to combine the outputs. The high switching speed inherent to IR light-emitting diodes (LEDs) and the potential for high power output makes them an appealing candidate to replace the thermal pixel arrays used for IRSP systems. To this end, research has been carried out to develop and improve the device performance of IR LEDs based on InAs/GaSb type-II superlattices (T2SLs). A common method employed to achieve high brightness from LEDs is to incorporate multiple active regions, coupled by tunnel junctions. Tunnel junctions must provide adequate barriers to prevent carrier leakage, while at the same time remain low in tunneling resistance to prevent unwanted heating. The performance of two tunnel junction designs are compared in otherwise identical four stage InAs/GaSb superlattice LED (SLED) devices for application in IRSP systems. This research culminated in the development of a 48 Μm pitch, 512$times512 individually addressable mid-wave IR LED array based on a sixteen stage, InAs/GaSb T2SL device design. This array was hybridized to a read-in integrated circuit and exhibited a pixel yield greater than 95 %. Projections based on single element emitter results predict this array will be able to achieve a peak apparent temperature of 1350 K within the entire 3-5 Μm band. These results demonstrate the feasibility of emitter arrays intended for IRSP systems based on InAs/GaSb SLED devices. Additionally, a dual wavelength 48 Μm pitch, 8x8 emitter array based on InAs/GaSb T2SL LEDs was developed and demonstrated. This design incorporates two separate, 16 stage InAs/GaSb SL active regions with varying InAs layer thicknesses built into a single vertical heterostructure. The device architecture is a three terminal device allowing for independent control of the intensity of each emission region. Each emitter region creates a contiguous pixel, capable of being planarized and mated to drive electronics.

The invasive nature and undesirable side-effects related to conventional cancer therapy, such as surgery and chemotherapy, have led to the development of novel drug delivery systems (DDS). A minimally invasive DDS using near-infrared (NIR) light as a trigger for drug release is investigated to reduce the adverse side-effects triggered by systemic delivery of chemotherapeutic drugs. The low tissue absorbance in the NIR region, λ = 650–2500 nm, allows the irradiation to penetrate through tissues to release cisplatin from a NIR-sensitive nanocomposite of Au-Au₂S. Our laboratory has recently shown that cisplatin can be effectively released from Au-Au₂S upon NIR irradiation. Cisplatin was loaded onto Au-Au₂S through its adsorption on COOH-functionalized alkanethiols coated on Au-Au₂S. The current work focuses on the development of methods to control the release of cisplatin. Drug release is controlled by either the irradiation parameters or the type of coatings. The effect of different coatings on NIR sensitivity and drug release is investigated. Molecular layers of HS-(CH₂)n-COOH and HS-CH₂-COO-CH₂(CH₂CH₂O)xCH₂-COOH have been successfully coated onto Au-Au₂S. The effect of different surface layers on drug adsorption is being examined. In addition, a mathematical model has been developed to describe the thermal effects of different irradiation parameters on soft tissues. / Singapore-MIT Alliance (SMA)

The Mini-EUSO (Mini - Extreme Universe Space Observatory) is an instrument for observation of ultra-high energy cosmic rays (UHECR) from space. It is designed to observe Earth from the international space station (ISS) in the ultra-violet (UV), visible (VIS) and near-infrared (NIR) light ranges. The UV sensor is the main sensor, designed and built by the EUSO collaboration. The visible and near-infrared sensors are secondary sensors. These are two cameras, FMVU-13S2C-CS and CMLN-13S2M-CV, from Point Grey Research Inc. The near-infrared light camera has a phosphor coating on the sensor to convert from near-infrared light to visible light, which is detectable by the camera's CCD. This thesis deals with the calibration and evaluation of the secondary sensors. This is done by first evaluating the bias and dark current for both cameras. After which a calibration is done using the light measurement sphere, located at the National Instituteof Polar Research (NIPR) in Midori-cho, Tachikawa-shi, Japan. Due to the low sensitivity of the near-infrared light camera, an evaluation of its ability to see celestialobjects are also performed. It is found that the visible light camera has a high bias with values around 5 ADU (Analog-to-Digital unit), but almost non-existing dark current, with mean values below 1 ADU. The visible light camera has good sensitivity for all the colors: red, green and blue. However, it is most sensitive to green. Due to this, it is easy to saturate the pixels with too much light. Therefore, saturation intensity was also examined for the shutter times of the visible light camera. This is found to be between 900μWm-2sr-1 and 1·107μWm-2sr-1, depending on color and shutter time. The near-infrared light camera is the opposite; it has a low bias with values below 1 ADU and a high dark current. The values of the dark current for the near-infrared light camera are highly dependent on the temperature of the camera. Mean values are below 1 ADU for temperatures around 310K, but mean values of almost 2 ADU at temperatures around 338K. The sensitivity of the near-infrared light camera is very low, therefore, the only way to detect a difference between the light levels of the light measurement sphere was to use a high ADC amplication gain. With this it was found that there is a power-law behavior, values between 1.33 and 1.50, of the relationship between pixel values and light intensity. This is likely due to the phosphor coating used to convert to visible light. When trying to detect celestial objects, the faintest object detected was Venus with a magnitude of less than -4.

京都大学 / 新制・課程博士 / 博士(情報学) / 甲第23543号 / 情博第773号 / 新制||情||132(附属図書館) / 京都大学大学院情報学研究科知能情報学専攻 / (主査)准教授 延原 章平, 教授 西野 恒, 教授 西田 眞也, 教授 佐藤 いまり(国立情報学研究所) / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

Photobiomodulation (PBM) therapy involves the irradiation of tissues with red to near- infrared (NIR) light at low power densities to stimulate healing, reduce inflammation, and promote optimal cellular functioning. These beneficial effects are thought to occur due to the absorption of NIR light by the chromophore, and terminal enzyme in the mitochondrial electron transport chain, cytochrome c oxidase (CCO). It is hypothesized that increased oxygen consumption due to the photostimulation of CCO, as well as photodissociation of the vasodilator nitric oxide from its binding site in the binuclear center of CCO, contribute to improved tissue healing by increasing blood flow to the irradiated region. Applied to the brain, PBM therapy has the potential to improve many neurological injuries and diseases for which reduced cerebral blood flow (CBF) is a common finding. This study examines whether cortical irradiation with NIR light has an impact on CBF in mice. Mice were administered brain PBM via 810nm, 190mW LED for 18 minutes. CBF was measured before, during, and after treatment using Doppler Optical Coherence Tomography. Results from 16 trials demonstrated a significant, 40% increase in CBF during NIR treatment. This CBF increase was not observed during control trials. Additionally, irradiation with a 730nm LED did not increase CBF, indicating that the blood flow increase observed with 810nm irradiation was not simply due to tissue heating. These findings provide support for the value of PBM therapy for the treatment of neurological conditions. / 2023-05-14T00:00:00Z

The magnetic (B) field in the disk of a galaxy may play an important role in the dynamics and evolution of the interstellar medium (ISM). The process by which the interstellar B-field is generated and maintained is not well understood, but the general expectation is that the generated B-field will be toroidal (parallel to the disk of the galaxy). The large-scale B-field threading the cold ISM of external galaxies can be probed via optical and near-infrared (NIR) polarimetric observations. However, scattered light can introduce false-positive B-field detections into these observations and is a source of contamination. This dissertation sets a context for observations of the Milky Way B-field by assessing the degree to which scattered light affects NIR polarimetry and reporting measurements of the B-fields in the disks of several external galaxies. The polarization properties of scattered light were investigated in order to better understand the degree to which scattered light may be a source of contamination in studies of the cold ISM B-field of external galaxies. The optical and NIR polarization of three, nearby, reflection nebulae was observed, and the wavelength dependence of the polarization percentage was measured. This wavelength dependence was found to be related to the characteristics of the scattering dust grain population with the general conclusion that the total amount of polarized, scattered light decreases with increasing wavelength. This analysis was repeated for the scattering-dominated galaxy M82 to test if similar results obtained for galaxies outside the Milky Way. Observations of this object indicate that the total amount of contamination from scattered light in this object is also less at NIR wavelengths than at optical wavelengths, and they confirm that B-field generated polarization can be detected in external galaxies. A sample of edge-on galaxies was observed for NIR polarization to measure the cold ISM B-field there. These observations indicate the likely presence of non-toroidal B-fields, localized, coherent B-field structures, and spiral disk structure detectable via NIR polarimetry. A comparison of the B-fields threading the cold and hot components of the ISM suggests that these B-fields may be dynamically distinct under certain conditions.

No description available.