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非弁膜症性心房細動(NVAF)患者における抗凝固薬選択と安全性転帰との関連：新規ユーザを対象とした実薬対照後ろ向きコホート研究
Get PDFBackground: Direct oral anticoagulants (DOACs) are preferred for stroke prevention in nonvalvular atrial fibrillation (NVAF); however, warfarin is still used. This study examined why physicians may choose warfarin over DOACs and the associated safety outcomes in patients with NVAF.
Methods: We conducted a new-user, active-comparator cohort study in newly diagnosed patients with NVAF to assess safety outcomes after the introduction of DOACs in Japan.
Results: The median observation period was 1120 days; 1428 patients started anticoagulation therapy with warfarin and 1551 with DOACs. Warfarin was chosen for patients with lower creatinine clearance and left ventricular ejection fractions and those using aspirin and verapamil. The unadjusted risk of major bleeding was considerably higher in the warfarin group but was nonsignificant after adjusting for variables associated with the choice of warfarin, in addition to age and sex. The risk of death was higher in the warfarin group, even after adjustments for relevant variables. However, high-risk subgroups, including those with older ages and multiple comorbidities, such as renal impairment, for whom warfarin was more likely to be selected, had severely compromised prognoses with either anticoagulant. The risk of stroke/systemic embolism was not significantly different between the two groups.
Conclusions: Warfarin is often chosen for older patients with multiple comorbidities characterized by reduced renal function, which is associated with a higher risk of major bleeding and mortality. These high-risk patients seem to have a poor prognosis regardless of the type of anticoagulant used. Thus, safe anticoagulant therapy remains a challenge for such patients.博士（医学）琉球大学University of the Ryukyu
The Start of Bicycle Parts Standardization Through Transformations of Local Supply Chain
Get PDFDespite the fact that much of the existing literature on Global Value Chains (GVCs) notes that bicycle parts are modular, it has thus far largely failed to identify exactly how bicycle parts were standardized in international markets. This paper uses national statistics, contemporary dissertations, and descriptions provided in both Japanese and German trade publications in order to focus on how bicycles became a modular product by the middle of 1930s. Analysis of that key question reveals that the transformation of local supply base triggered the technological upgrading of the Japanese bicycle parts industry and this transformation was supported by the Japanese export-oriented regime
複数方式の多基準意思決定法による農村地域の評価に関する研究：インドのゴンダ地域を対象として
Get PDFThis thesis presents a comprehensive methodology for assessiI1g rural development and it has been tested on India areas, focusing on the creation of a Rurality Index through a modified Fuzzy Analytic Hierarchy Process (F-AHP). The methodology is applied to various case studies within Gonda District, Uttar Pradesh, India, aiming to rank and zone villages based on their socio-economic and infrastructural conditions. The research compares the modified F-AHP with other Multi-Criteria Decision-Making (MCDM) models, including TOPSIS, PROMETHEE, VIKOR, ELECTRE, and WPM, to evaluate the developed methodology effectiveness in calculating the rurality index against other tools. The research also utilizes Geographic Infonnation Systems (GIS) for spatial zoning for easy interpretations and management of the results, the study identifie areas most in need of development interventions. Key findings from the case studies illustrate the significant challenges faced by villages in dispersed and nucleated settlement patterns, including poor access to healthcare, education, and infrastructure. By employing sensitivity analysis, this research demonstrates how expert judgment and criteria weighting impact village rankings, highlighting the impo11ance of localized ecision-making for effective rural development. The methodology and findings aim to provide policymakers with a tool to prioritize resomce allocation and improve rural development outcomes in underdeveloped regions oflndia.博士（工学）琉球大学University of the Ryukyu
ヘラート旧市街地の方位の研究
Get PDFThe following research is based on three journal papers, two of which have been published, and one is currently under review. It investigates the historical and architectural evolution of the Old City of Herat, Afghanistan, by analyzing historical maps, radiocarbon dating of the city wall, and the urban orientation of its structures. First, the detailed comparison of maps from 1840, 1880, and 1915 identifies the 1880 map by James Wyld and the 1915 map by Oscar Niedermay er as crucial resources. The 1880 map accurately depicts the configuration of the city wall, road networks, and cemeteries outside the Old City, while the 1915 map provides precise details about buildings within the Old City. Second, the result of Radiocarbon dating of plant fibers in the city wall suggests construction during AD 441-649, a period marked by significant historical events, including the rise of Arab-Islamic powers and the transformation of Herat into a vibrant urban center. This evidence points to the first confirmed pre-Islamic activity in the Old City, underscoring its role as a site of cultural and historical convergence. Third, further analysis reveals that the azimuth of qibla of mosques in the old city of Herat, including the Herat Grand Mosque (Masjid Jameh), generally faces west. This westward orientation reflects practical urban planning decisions to accommodate religious practices, aligning the mosques towards the Kaaba, but the accurate angle of the Kaaba is (about 237 degrees). Despite invasions and natural disasters, Herat's urban structure, characterized by its cardinally oriented square city wall and crossroads, has been resiliently maintained, highlighting the interplay between geography, architecture, and cultural identity. The study concludes that the Old City of Herat is a testament to its historical legacy. It calls for further research through detailed excavation surveys and additional radiocarbon dating. The findings affirm Herat Old City as a significant historical and cultural intersection site, enriching our comprehension of Afghan heritage.博士（工学）琉球大学University of the Ryukyu
コユビミドリイシの光受容に関する生理学的研究
Get PDFLight plays a crucial role in regulating the biological activities of reef-building corals. However, the understanding of opsin-based photoreception and the subsequent physiological responses in coral hosts remains • limited.· This study aimed to investigate the photophysiological processes in the scleractinian coral Acropora digitifera.
Initially, three membrane photoreceptor genes (opsinl, opsin2, opsin3) were cloned, and their molecular characteristics and locations. in coral tissues were identified. The first experiment examined the in vivo photoreception of opsins under various light spectrums. Additionally, the responses of eight metabolism-related genes were analyzed, including two calcification genes (ca, pmca), two sugar transport genes (sglt, ppplr), two oxygen homeostasis genes (hifl a, egln), and two stress indicators (sod, hsp70) via real-time qPCR. Under natural light with a day-night cycle, opsinl and opsin3, as well as calcification(pmca) and oxygen homeostasis (hifl a) genes, showed a day-high and night-low expression pattern. When branches were exposed to a day-night cycle with red LED lighting, there was an increase in transcript levels of opsinl, opsin3, ca, pmca, hifl a, and sglt during the photophase, but not with blue or green LED lighting. Opsin3 upregulation occurred within 4 hours of red LED light exposure at night, indicating that A. digitifera can respond to long wavelengths of light, crucial for shallow water light adaptation.
The second study examined circadian regulation in the photoreception process. Circadianrelated genes (cryl, cry2, cry3, clock, cycle, slmb) were analyzed for their mRNA expression over a 24-hour diel cycle under light-dark (LD) and constant dark (DD) conditions. Four clock genes (cryl, cry2, cry3, clock) displayed oscillation patterns under LD but not under DD, indicating they are light-dependent clock genes. Conversely, cycle and slmb exhibited oscillations under both LD and DD, suggesting specific roles in circadian regulation. Opsin expression under both LD and DD conditions suggested that circadian genes might regulate their expression. Overall, the results indicated that diel physiological responses in photoreception, calcification, and oxygen homeostasis in A. digitifera are partially governed by the circadian system and entrained by external light cues.
The third study focused on photoreception during the larvae stages. Free-swimming larvae were reared under blue and red artificial light for six days. At the end of the experiment, larvae under blue light showed higher metamorphosis and settlement rates compared to those under red light. RNA-seq analysis identified differentially expressed genes (DEGs) involved in photoreception (crys, npas2), calcification (ca2), and immune regulation (hifl a, hey) under blue light treatment, supporting the hypothesis that blue light benefits larvae development, especially in the transition from metamorphosis to settlement.
This study systematically • investigated the photophysiology and downstream physiological responses in different life stages of corals, particularly focusing on photoreceptors under various light conditions. The findings indicate that the expression of photoreceptors. is controlled by both external light stimulation and internal circadian rhythms. Blue light positively impacts larvae development in terms of circadian regulation, skeleton production, and immune response. These insights enhance our understanding of coral physiological responses to different light spectrums, providing a comprehensive perspective on coral photophysiology.博士（学術）琉球大学University of the Ryukyu
琉球列島サンゴ礁域に生息するアワモチ科(軟体動物:腹側綱)の多様性、分布および食用利用に関する研究
Get PDFFamily Onchiiidae consists of air-breathing sea slug that lack internal or external shell. They are mostly found in intertidal areas across globe, except in the polar regions, and inhabit marine habitats. Although they are known to be commonly distributed in tropical to temperate of Indo-West Pacific region, information about the diversity of family Onchidiidae in the Ryukyu Islands is greatly lacking. Particularly, genus Peronia serves as an important traditional food source on many islands of the Ryukyus, but due to extremely similar gross morphology among the species, frequent misidentification of this family occurred in guidebooks and literatures. Accurate species identification requires detailed taxonomic analyses that incorporate molecular and morphological datasets, and literature reviews. Thus, in this thesis, I focused on three genera of family Onchidiidae; Peronia, Wallaconchis and Onchidella inhabit intertidal coral reef environments, and aimed to accomplish three goals. Firstly, I investigated the species diversity and distribution ranges of three genera across 40 intertidal areas in 11 islands of the Ryukyu Islands, with Chapter 1 focused specifically on genus Peronia and Chapter 2 adressed genera Wallaconchis and Onchidella. As a results of mitochondrial DNA barcoding using COI and 16S regions, the Ryukyu Islands harbor at least eight species from three genera; four species of Peronia (P. verruculata, P. peronii, P. okinawensis, and P. setoensis), three species of Wallaconchis (W. ater, W. nangkauriensis, and Wallaconchis sp.) and one species of Onchidella (Onchidella sp.). Species of Peronia distributed Iriomote-jima to Yakushima islands, and Wallaconchis and Onchidella are distributed in Okinawa-jima to Kikai-jima. Alive photographs of each species are also provided as potential identification tools, as well as to understand the colour variations observed within the species. Secondly, to enhance the molecular datasets of family Onchidiidae in public repositories, I aimed to provide the complete mitochondrial genomes of genus Peronia. The characteristics of mitogenomes of four species of Peronia are described in Chapter 4, with the first records of P. okinawensis and P. setoensis. It revealed that all species shared the same gene orientation and arrangement as previously described mitogenomes in family Onchidiidae. Thirdly, I aimed to explore the traditional Peronia fishery across eight islands through in-person interview with locals in Chapter 5. The Peronia fishery was observed from eight islands, either as active practice or one that has diminished over time. While locals recognized Peronia as a food source by locals, but familiarity with them varied slightly across eight islands. Overall, this thesis has revealed that currently the Ryukyu Islands hold the highest species diversity of genus Peronia, with four species coinhabit the same intertidal areas, as well as five species from three genera sympatrically existed. Although species of Onchidiidae can be currently considered as “common” in the Ryukyu Islands, more studies are needed to investigate the relationships between their diversity and the impacts of artificial disturbances, coastal developments, and overexploitations in intertidal areas to protect this unique biodiversity.博士（理学）琉球大学University of the Ryukyu
Morphological and molecular phylogenetic systematics of the mantis shrimp superfamily Lysiosquilloidea
Get PDF口脚目Stomatopodaは一般にシャコ類と呼ばれる甲殻類で,世界で約500種が,日本からは約70種が記録されている.シャコ類の現生分類群である単楯亜目Unipeltataには7上科が知られており,その中でトラフシャコ上科Lysiosquilloideaはシャコ上科Squilloideaやフトユビシャコ上科Gonodactyloideaに次いで種多様性が高いことが知られている.しかし,トラフシャコ上科の種多様性や分布に関する調査は,国内では特に進んでいない.これには,トラフシャコ上科の多くの種が深く⾧い巣穴を砂泥底に掘って棲息していることなどが影響していると考えられる.トラフシャコ上科はこの種多様性のみならず,大小様々な体サイズの種が知られ,さらに捕脚形態の多様性も高いことから,形態的にも多様であると言える.この形態的な特徴と系統との関係も,トラフシャコ上科を主な対象にした分子系統学的研究がされてこなかった経緯から不明である.先行研究ではシャコ類全体の分子系統解析にトラフシャコ上科の数種が使用され,ヒメシャコ科Nannosquillidaeやヨンシャコ科Tetrasquillidaeの多系統性が示唆されてきたのみであった.そこで国内各地での野外調査や,国内外の博物館収蔵標本調査を通して,トラフシャコ上科に焦点を当てた研究を実施した.得られた標本について,形態学的な調査とミトコンドリアDNAの部分配列と核DNAの部分配列を用いた系統解析を行った.その結果,最大で全⾧40cmにも及ぶ種が知られるトラフシャコ科Lysiosquillidaeのトラフシャコ属Lysiosquillaからは,未記載種の可能性がある1種と,日本初記録種の3種を発見した.ヨンシャコ科Tetrasquillidaeはこれまでに国内から3種のみがごくわずかに記録されていたが,本研究ではそのうちの2種を再発見するとともに,新属新種IncertasquillachimeraAhyong,Nakajima&Naruse,2024を発見,記載することができた.ヒメシャコ科Nannosquillidaeでは本研究の以前には全体で15属64種が,国内では4属9種が知られていたが,本研究ではトラフヒメシャコ属Acanthosquillaに国内外から9種の未記載種を発見した.そのうち2種は新種A.ryukyuensisNakajima,Reimer&Naruse,2023とA.shoheiiNakajima,Reimer&Naruse,2023として記載することができた.また,これまでトラフヒメシャコ属に含められてきた日本未記録種を基に,未記載属を設立できることを示した.加えて,ミツツノヒメシャコ属Alachosquillaの再定義を行い,これに含まれていた1種を基に未記載属を設立できることを示した.さらに,トラフヒメシャコ属に似る未記載属未記載種を発見した.加えてシマトラフヒメシャコ属Bigelowinaから1種,コドモヒメシャコ属Pullosquillaから少なくとも2種の未記載種を発見した.以上のように,本研究ではトラフシャコ上科の国内既知種をほぼ全て再発見するとともに,複数の新種や新属新種,未記載種,未記載属,国内未記録種を発見することができた.本研究において形態的に同種に同定した一部の種については,産地の異なる標本間において別種相当と考えられる遺伝的距離が見られ,隠蔽種の存在が示唆されている.したがって今後もさらに種数が増加する可能性がある.本研究では発見された種や属の系統的位置や特徴的な外部形態との関係を検討し,それによって認識された新たな高次分類の判別形質の提案なども行っている.博士（理学）琉球大学University of the Ryukyu
好酸球性副鼻腔炎における酪酸による2型炎症の抑制
Get PDFButyrate and other Short-chain fatty acids (SCFAs) are microbial metabolites from Bacteroides and Clostridium species that may suppress type 2 inflammation. However, the mechanisms of SCFAs in the nasal sinuses are not fully understood. We aimed to clarify the in vitro and in vivo roles of SCFAs in eosinophilic chronic rhinosinusitis (ECRS) pathophysiology. We investigated whether SCFAs induced changes in type 2 cytokines, IgE, and apoptosis and the roles of GPR41, GPR43, and histone deacetylase. Analysis of the control subjects demonstrated that butyrate of SCFAs effectively inhibited type 2 cytokine production in PBMCs, ILC2s, and CD4+ T cells and IgE production in CD19+ B cells. In annexin V analysis, butyrate also induced late apoptosis of PBMCs. The butyrateinduced inhibition of type 2 cytokines appeared involved in histone deacetylase inhibition but not in GPR41 or GPR43. In an analysis of ECRS in humans, butyrate inhibited type 2 cytokine production in PBMCs and nasal polyp-derived cells. The butyrate concentration in nasal lavage fluid was significantly decreased in ECRS patients compared to controls and non-ECRS patients. Our findings confirm that butyrate can inhibit type 2 inflammation and may be a potential therapeutic target for ECRS.博士（医学）琉球大学University of the Ryukyu
赤道マラッカ海峡における海面上昇とその河口域での潮汐変形および潮津波発生への影響
No full textThis study examines the interactions between tidal bore dynamics, sediment transport, water quality, and sea level rise (SLR) in the Kampar Estuary, Indonesia, a macro-tidal system dominated by semidiurnal constituents (M2, S2). The estuary’s flood-dominant regime, especially during 4-meter spring tides, facilitates tidal bore formation. Real-time ADCP and acoustic backscatter data reveal a 1.5 m bore height decline every 20 km upstream, with abrupt velocity shifts (–0.9 to 0.2 m/s) that trigger sediment resuspension. Bore passage increases sediment flux up to 3.7 times compared to ebb tide conditions. Tidal bores also impact water quality. WQI and EI analyses show poor downstream conditions (WQI 1.5), with high nutrient loads and hypoxia linked to bore-driven mixing. Upstream, eutrophication remains elevated, exacerbated by acidic conditions (pH ≤ 5) during ebb tides, likely due to anthropogenic input. These findings highlight the need for stronger pollution control and sustained monitoring.
Sea level data (1992–2019) from Tanjong Pagar indicate a rising trend (0.24–0.39 cm/year), with variability linked to ENSO, MJO, and monsoonal winds. These factors amplify tidal constituent amplitudes and shorten tidal phases. Projections show 8.9–18.3% amplitude increases by 2050–2100, raising bore heights by up to 1.5 m and boosting turbulent velocities to 1.1–1.5 m/s, intensifying erosion and flood risks. Modeling a 0.78 m SLR scenario predicts increased tidal asymmetry, with M2 and M4 amplitudes rising by 16.35% and 55%, respectively. This accelerates sediment redistribution, with up to –8.48 m erosion in mid-estuary and +9.40 m deposition downstream. Sediment fluxes reach 3.5 kg/m²/s, with bore-driven transport 2.6–3.8 times greater than regular tidal flows, further destabilizing the estuary. These results underscore the Kampar Estuary’s vulnerability to SLR-driven hydrodynamic changes. Adaptive measures, such as embankment reinforcement, water and sediment management, mangrove conservation, and integrated coastal planning—are essential for enhancing resilience in Southeast Asia’s macrotidal estuaries.博士（理学）琉球大学University of the Ryukyu
アフガニスタンにおける学校校舎の耐震性能評価のためのレンガ組積造 の圧縮強度に関する研究
Get PDFThis thesis investigates masonry structures'compressive strength and seismic perfonnance using locally
sourced clay bricks in Nangarhar, Afghanistan, and the Adopted Japanese Standard for Seismic Capacity Evaluation of Masonry
Infilled RC buildings. In regions like Afghanistan, where seismic activity is prevalent, understanding the behavior of indigenous
materials under such conditions is critical for public safety, particularly in public infrastructure such as school buildings. Despite the
widespread use of clay brick masonry for construction, a significant gap exists in the data regarding these materials'compressive
strength and seismic resilience. This research addresses this gap through extensive experimental investigations and the development
of mathematical models that accurately predict the compressive strength of local masonry materials.
A vital component of this research is the development of· empirical equations tailored to the local context of
Afghanistan. These predictive models were developed through multi-power regression analysis and validated against existing
empirical models from global studies. The equations account for the unique properties of local bricks and mortar, yielding more
accurate compressive strength predictions than existing models. Additionally, this study identifies key factors, such as material
heterogeneity and the anisotropic behavior of brick and mortar, which contribute to the variability in structural perfonnance. Two
distinct masonry groups were identified, each requiring specific parameters for optimal structural design. Group 1 emphasized the
influence of brick strength and slenderness, while Group 2 focused on mortar strength and joint dimensions.
The study also utilizes a comprehensive experimental database, including materials from various regions and sources,
to examine the complex interactions between bricks, mortar, and geometric factors. A series of compressive strength tests on
masonry prisms were conducted, with results validated through fmite element modeling (FEM). The experimental results confmned
the significant influence of the slenderness ratio and joint-thickness on the overall compressive strength of masonry.
Furthennore, this research evaluated the seismic capacity of masonry-filled RC school buildings using modified
Japanese seismic standards. The seismic analysis revealed significant weaknesses in these structures, mainly due to poor-quality
materials and lack of reinforcement in masonry infills. The evaluation identified critical deficiencies in the seismic capacity index
(/,) based on the Strength Index (C) and Ductility Index (F) below acceptable thresholds. Many school buildings in the study area
were classified as structurally unsafe, indicating a high risk of collapse during seismic events. The seismic demand index (l,o),
representing the building's required capacity to resist seismic forces, was also insufficient in most cases, highlighting the urgent
need for retrofitting.
The findings of this thesis contribute to the development of more accurate and region-specific building codes aimed at
improving the resilience of masonry structures in earthquake-prone areas. It emphasizes the importance of tailored design standards,
particularly for public infrastructure such as school buildings, to ensure the safety of occupants during seismic events. This study
provides a comprehensive framework for improving Afghanistan's construction practices and building code compliance by
integrating experimental results with advanced computational models and seismic assessments.博士（工学）琉球大学University of the Ryukyu