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金量子ドットの表面プラズモン共鳴場増強蛍光特性とそのセンサー応用の研究
Get PDF新潟大学Niigata University博士（工学）This dissertation presents the combination of the surface plasmon resonance (SPR) phenomenon and fluorescence spectroscopy to enhance fluorescent intensity in real-time analysis. The enhancement utilizes the strong evanescent electromagnetic field to excite fluorophores near the metal surface in prism- and grating-coupled surface plasmon resonance. This study aims to develop a device for observing the SPR and SPR field-enhanced fluorescence (SPF) properties of gold quantum dots (AuQDs) and investigating their applications. Thus, this study consists of two research works. First part demonstrates the SPR enhanced SPF phenomena of AuQDs. This phenomenon depends on the distance between the AuQDs and the aluminum (Al) film, and it is applied to hydrogen peroxide (H2O2) sensing. The second part displays the optical properties of AuQDs coated on an Al grating substrate, focusing on the ability to tune SPR-enhanced fluorescence response via mechanical stretching. In first project, we investigated the SPR and SPF properties of AuQDs on polyelectrolyte multilayers deposited onto an Al substrate. A 20 nm-thick layer of Al was first coated onto high refractive-index glass. Subsequently, polyelectrolyte multilayers comprising poly(diallyl dimethyl ammonium chloride) (PDADMAC) and poly(sodium 4-styrenesulfonate) (PSS) are adsorbed onto the surface of the Al film by a layer-by-layer (LbL) method. Afterward, AuQDs are deposited on the prepared PDADMAC/PSS ultrathin films to study the SPR behavior and fluorescence enhancement/quenching phenomenon. The SPR dip peak shifts to a higher angle, and the fluorescence intensity increases when the optimal distance between the AuQDs and Al layers is reached, determined by the thickness of the PDADMAC/PSS films. For H2O2 sensing, silver nanoprisms (AgNPrs) are initially deposited onto the layer of AuQDs. Then, the fluorescence intensity of AuQDs decreases as a result of energy transfer from the AuQDs to the AgNPrs. Moreover, the fluorescence intensity of AuQDs is recovered after the injection of H2O2 solution, with the SPF intensity from the recovery being directly proportional to the concentration of H2O2 (0.0010 nM to 100 nM). This result is attributed to the etching effect or oxidation reaction of AgNPrs, indicating the disintegration of AgNPrs. Therefore, this developed system has the potential to be applied to other sensors for detecting H2O2. In the second project, we studied the phenomena of SPR and SPF of AuQDs deposited on an Al/polydimethylsiloxane (PDMS) grating film by mechanically stretching it to modify the grating pitch. A 150 nm-thick layer of Al was initially coated onto the prepared PDMS grating mold to observe the SPR properties. The incident light angle was adjusted in 5° increments (from 5°to 60°) to tune the SPR excitation wavelength of the Al/PDMS grating film. Furthermore, the SPR reflectivity spectra shifted to higher wavelengths (approximately 20 nm) when stretching the PDMS grating substrate in the range from 0 to 1.0 mm. Subsequently, the AuQDs were deposited onto an Al/PDMS grating layer to investigate the ability to tune SPR-enhanced fluorescence during substrate stretching. Additionally, a violet laser (405 nm) with p-polarization was utilized as the excitation light to observe the SPF phenomenon of AuQDs. The fluorescence intensity of AuQDs on the Al/PDMS grating substrate increases by tuning the SPR excitation wavelength to match with the fluorescence excitation light of AuQDs. The SPR excitation wavelength is related to the +1 SP-dispersion mode, which occurs as the grating substrate stretches from 0 mm to 1.0 mm, causing a shift in reflectivity to a higher wavelength. Furthermore, in the observation of stretched AuQDs/Al-grating PDMS film, the SPF intensity increases at fixed incident angles of 15°and 35°, while the fluorescence decreased at an incident angle of 40°. Thus, the interaction between the electric field of the enhanced SP mode and the fluorescence excitation light can tune the SPF intensity. The potential for mechanical tuning in SPF spectroscopy makes it applicable to optical sensors.新大院博(工)第562
Study on the Sources of Competitiveness and Corporate Behavior of Japanese Electronic Parts Manufacturers
Get PDF新潟大学Niigata University博士（学術）This study aims to examine the actual corporate behavior and capabilities that are the source of the Japanese electronic parts manufacturers’ (JEPMs) competitiveness, which is currently strong. The strength of JEPMs is comprised primarily of manufacturing and the incremental evolution of technologies and skills cultivated through consistent daily routines. Most of their capabilities can be classified as ordinary capabilities (OCs), and dynamic capabilities (DCs) are difficult to find in a clear form. However, the ability to convert OCs into DCs (or DCs-like capabilities) is what maintains a high level of competitiveness in the global electronics market, which is rapidly evolving. This study aims to reexamine existing theories of DCs using case studies of JEPMs as evidence. Specifically, we would like to evaluate existing DC theories by analyzing how JEPMs respond to market and business environment changes. The author considers that drawing a clear distinction between these two capa-bilities is difficult, and that there may be gradations between them in reality. This study proposes the concept of synchro capability, which is the capacity to adapt to the environment as a bridge between these two types of capabilities. Based on actual corporate activities and case studies, this study exam-ines how JEPMs develop a high level of competitiveness and adaptability to changes in the business and market environment.新大院博(学)第228
西南日本中央構造線沿いの脆性 : 延性遷移領域をまたぐ三次元断層帯内部構造
Get PDF新潟大学Niigata University博士（理学）The features and distribution of fault rocks along the Median Tectonic Line (MTL), SW Japan, were characterized to establish the 3D architecture of the fault zone across the brittle–plastic transition. Cataclasites exposed close to the lithological boundary fault (the MTL) can be divided into those formed by sinistral faulting at temperatures of ～300 ◦C (black cataclasite within the BW zone) and those formed by dextral faulting at ～250 ◦C (scaly cataclasite). Mylonites distributed to the north of the cataclasites were formed by sinistral faulting and can be divided into lower-temperature mylonite (L-T mylonite) close to the MTL and higher-temperature mylonite (H-T mylonite) distant from the MTL, where deformation temperatures were lower and higher than 400 ◦C, respectively. Structures formed by sinistral faulting are oblique to those formed by dextral faulting, indicating that the former structures are older than the latter. In the structures formed by sinistral faulting, the dipping angle of the unit faces becomes steeper as closer to the MTL, indicating that there is a cross-cutting relationship between each structural unit. Structures formed by sinistral faulting underwent deformation around the brittle–plastic transition. Thus, the MTL fault zone records deformation through a crustal section. Microstructural observations suggest that the differential stress just below the brittle–plastic transition (L-T mylonite) was ～160 MPa and that this value may not change substantially in the deep crust (H-T mylonite). Two types of ultramylonites were identified along the MTL; one occurs in the BW zone, while the other occurs in the L-T ultramylonite. A significant difference between them is the matrix constituent minerals. The matrix of the former mainly consists of white mica, while that of the later mainly consists of fine-grained feldspar and quartz, suggesting a significant influx of fluids in the BW zone. This possibility enhances dissolution and precipitation reactions in the BW zone, resulting in the formation of black cataclasite as a strain localized zone at the brittle regime. The results of this study implies that strain localization beneath the seismogenic zone may control the generation of seismicity.新大院博(理)第497
Engineering Analysis of "Searching" and "Viewing" Behaviors by Measuring Gaze Position : Target Searching by Visual Search, and Viewing Smartphone for a Long Time
Get PDF新潟大学Niigata University博士（工学）新大院博(工)第555
血清アミラーゼと２型糖尿病発症との関連を検討する後ろ向きコホート研究 : 虎の門病院健康管理センター研究23
Get PDF新潟大学Niigata University博士（医学）Introduction Low serum amylase values are cross-sectionally associated with the prevalence of type 2 diabetes mellitus (T2DM) but have not been shown to be longitudinally associated with its incidence. This retrospective cohort (ie, historical cohort) study aimed to examine the association of previously lowered levels of serum amylase with incident T2DM. Research design and methods Examined were 8316 individuals who had annual health examinations for 6 years (ie, 7 times) at the Toranomon Hospital Health Management Center. The trajectory of serum amylase as the study exposure was classified into two elements: (1) serum amylase level at entry and (2) change in serum amylase, which was expressed as the annual change rate. The annual change rate was calculated by dividing the change in the amylase values according to follow-up periods. Regression analyses were performed to examine the association between low and decreased levels of serum amylase and the incidence of T2DM. Results Analyzed were 6917 individuals who had not developed T2DM within 1 year after cohort entry. T2DM thereafter occurred in 1021 patients. Cox regression indicated that the adjusted HR (95% CI) for incident T2DM for amylase ≤57 IU/L (quintile (Q) 1) was 0.97 (0.84 to 1.13) compared with amylase ≥58 IU/L (Q2–Q5). Logistic regression indicated that the adjusted OR (95% CI) for an annual change rate of amylase ≤−2.0% (Q1) vs ≥−1.9% (Q2–Q5) was 3.53 (3.00 to 4.16). The adjusted ORs were consistently significant throughout sensitivity analyses according to baseline amylase and the combination of age, body mass index, and hemoglobin A1c. Conclusions Results showed that not low but previously decreased serum amylase was a risk factor for T2DM, suggesting the significance of periodic examinations of serum amylase values to detect individuals at high risk of T2DM.Izumi Ikeda, Kazuya Fujihara, Taeko Osawa, Yasunaga Takeda, Mariko Hatta, Yasuhiro Matsubayashi, Satoru Kodama, Yasumichi Mori, Takashi Kadowaki, Ritsuko Honda, Yasuji Arase, Hirohito Sone - Retrospective cohort study to examine the association between serum amylase and the incidence of type 2 diabetes mellitus, Toranomon Hospital Health Management Center Study 23 (TOPICS 23): BMJ Open Diabetes Research & Care 2023;11:e003482.新大博（医）第1192
