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- doctoral thesis
doctoral thesis
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本研究の目的は、健常人において、血漿中の尿酸値(UA)と分枝鎖アミノ酸および芳香族アミノ酸(BCAAおよびAAA)の濃度の関連を明らかにすることである。
合計2,804人の健常人について、血漿UAレベルに応じて3つのグループに分類した。その3グループ間における、BCAAとAAAの濃度の関連を、分散分析(ANOVA)と共分散分析(ANCOVA)により解析した。
この研究で対象としたすべてのBCAAとAAAの濃度は、トリプトファンを除き、全てがUA濃度の各レベルに応じて、漸進的に有意に増加した(P<0.001)。また、全体として、個々のBCAAおよびAAAについて、最低のカテゴリーの差にくらべ、高いカテゴリーの差の方が、より大きかった。本研究は、血漿中のBCAAおよびAAAと、UAのレベルについて、潜在的に、密接な関係が存在していることを示唆した。今後、それらの間の因果関係および相互作用を解明する研究が必要である。
Creators :
石丸 泰隆
Fiber-reinforced polymer (FRP) rods fabricated from unidirectional fibers and a polymer matrix strengthen effectively reinforced concrete (RC) members. The pultrusion is a production method of FRP rod. The FRP rods show various advantages, such as light and no-corrosion. Most FRP rods have higher tensile strength than standard steel bars. Therefore, the FRP rods can be used as an alternative reinforcement of steel bars in RC structures. In addition, FRP rods can be applied in near-surface mounted (NSM) systems for strengthening existing concrete structures. The tensile properties of FRP rods in adhesively bonded anchorages are expected to be studied in detail. Numerous experimental studies were conducted on FRP rods made of glass, carbon, aramid, or basalt fibers. The previous studies have reported that the tensile properties of FRP rods are affected by the shear-lag effect. However, these studies referred to the tensile failure, the shear-lag effect of FRP rods as a phenomenon without a mechanical explanation. Moreover, the effects of mechanical properties of fibers, matrix, fiber-matrix interface on FRP rod properties have not been investigated in detail.
To quantify factors affecting the tensile properties of FRP rods, this study performed a numerical investigation on aramid FRP rods to assess the shear-lag effect, tensile load-capacity, and tensile strength. In addition, the effects of fiber, matrix, and fiber-matrix interface on the behavior of FRP material in three dimensions were demonstrated by micro-models. Firstly, two representative volume element (RVE) models of fibers and matrix were proposed to predict engineering constants and strengths of the FRP material in three dimensions. Based on the predicted strength, the criteria were designed. Then, the main simulation, including the FRP rod, the filling material, and the steel tube, was carried out to analyze FRP rods under the variation of interfacial conditions between materials, including full-bonding strength and partiallybonding strength models. In the partially-bonding strength model, the interfaces between materials were simulated as cohesive zone models with the variation of bond strengths and fracture energy release rate.
A technique called submodeling was applied to enhance the simulation results. The submodel was cut from the main simulation model and only applied to simulate FRP rods with finer meshes. The study proposed a procedure for calculating the stress distribution in any cross-section of an FRP rod. The simulation results agreed well with the previous experimental study. The findings clearly indicated the position of the failure section in which the tensile stress distribution is unequal. The load-capacity, failure modes, shear-lag effect were predicted based on the maximum stress criterion. The results revealed that the FRP material strengths enforce the failure in two modes associated with the transverse and longitudinal directions of FRP rods. In addition, diameter is a significant factor that increases the shear-lag effect and reduces the tensile strength of the FRP rods. The numerical simulation provided a new method to predict the load-capacity of FRP rods. The study consists of 6 chapters. Outline of the chapter was presented as follows:
Chapter 1 introduces about kinds of FRP rods and their application in civil engineering. The chapter shows the research objects, the gaps in composite studies, and the scopes of the present research.
Chapter 2 summrizes the review of previous studies related to the theoretical studies of the composite materials. The chapter reveales the gap of theory. In addition, the study compares the advantages and disadvantages of previous studies and proposes methods and models for the present study.
Chapter 3 presents the simulations of the representative volume element (RVE) models to determine the mechanical properties and strengths of composite materials. The study investigates the effects of the fiber properties and fiber-matrix interface on composite mechanical properties in detail. The RVE-1 model was employed to predict engineering constants of the FRP material. The RVE-2 was applied to predict the tensile and shear strengths in three dimensions.
Chapter 4 shows the numerical simulations of the FRP rod tensile tests with various cases of the materials in Chapter 3. The models are built in two cases of the interface between the FRP rod and filling material: full-bonding and partially-bonding strengths. In the case of the full-bonding strength, three models are built with three hypotheses of FRP rod material. Three models, A, B, and C, were proposed to demonstrate the effect of fiber properties on FRP properties. Model A was built based on the hypothesis that the FRP rod is made of transversely isotropic fibers. Model B was made to simulate with an FRP rod of isotropic fibers. Model C assumes the FRP rod as an isotropic material. In the case of the partially-bonding strength, the study models various interface cases between the FRP rod and the filling materials to investigate the bonding effects. The proposed models were applied to simulate FRP rods from D3 to D8 to analyze the diameter effect.
In Chapter 5, the difference between the proposed models was discussed to show the advantages and disadvantages of each model. Firstly, the study compared models (A, B, and C) to highlight the effect of fiber properties on FRP rods. Secondly, the study compared the partially-bonding strength and full-bonding strength models to investigate the bonding effects on the tensile properties of FRP rods. Moreover, the chapter illustrates the existence of the shear-lag effect and demonstrates the diameter effect on tensile strength in FRP rods.
Chapter 6 summarizes the novel findings and research significance of the study. In addition, recommendations for future works were also presented.
Creators :
Vo Van Nam
抗がん剤の副作用である口腔粘膜炎の改善にはエレンタール^(R)は有効であることが報告されている。5-フルオロウラシル (5-FU) の副作用には口腔粘膜炎がある。そこでエレンタール^(R)の中で口腔粘膜炎の改善に最も有用な成分の特定を試みた。マウス(対照群を除く)に5-FUを4日間腹腔内注射し、生理食塩水(対照群、5-FU群)、デキストリン(デキストリン群)、アミノ酸(17AA群)、エレンタール^(R)(エレンタール^(R)群)のいずれかを7日間投与した。
Creators :
藤原 里衣子
小胞体ストレスの増加は、動脈硬化において血管平滑筋培養細胞(VSMCs)の形質転換(分化→脱分化)と強く関連している。小胞体のCa2+貯蔵量減少は、VSMCs における小胞体ストレスの増加の主要な原因の一つである。リアノジン受容体(RyR)は筋小胞体膜上に存在する主要なCa2+放出チャネルである。正常細胞の安静状態ではカルモジュリン(CaM)はRyR と結合し、RyR を閉鎖した状態で安定化させている。CaM とRyR の結合が減弱すると、RyR から異常なCa2+漏出が起こり、Ca2+貯蔵量が減少し、小胞体ストレスが増加する原因となり得る。そこで我々は、マウスのVSMCs を用いてRyR に結合しているCa(CaM-RyR)が小胞体ストレスにより引き起こされるVSMCs の形質転換に重要な役割を果たしているか否か、また、CaM-RyR の結合親和性を高める作用を有するダントロレン(DAN)がVSMCs の形質転換に影響を与えるか否かを評価した。
小胞体ストレスによりCaM がRyR から解離し、核内へ移行することにより、MEF2 とKLF5 の核内での発現量が増加し、このMEF2-KLF5 のシグナル伝達経路が活性化することでVSMCs が形質転換(分化→脱分化)し、増殖能や遊走能を有するようになり動脈硬化巣の形成や不安定化につながるという新たな知見を得ることができた。さらにCaM-RyR の結合親和性を高めるDAN は、RyR チャネルを安定化させ、異常なCa2+漏出を抑制し、小胞体内のCa2+貯蔵量を保持することで小胞体ストレスの増加を抑制し、さらにCaM の核内への移行を制御することで、MEF2-KLF5 経路の活性化を抑制し、その結果としてVSMCs の形質転換を抑制することが示され、動脈硬化巣の進展化、不安定化に対する全く新しい治療戦略となり得る可能性があることが示唆された。
Creators :
内田 智之
背景:顕微鏡的多発血管炎 (MPA) は全身臓器が障害される疾患である。しかしながら、MPA患者における心臓超音波検査(心エコー図検査)における指標の特徴については不明な点が多い。
目的:本研究は、単施設後ろ向き研究で、ステロイド療法の新規導入または再導入後2週間以内に心エコーを行ったMPA患者15名を対象とし、その心エコー所見の特徴について検討することを研究の目的とした。30人の年齢・性別をマッチさせた心疾患のないコントロール群と比較検討した。
方法と結果:左室径、左室駆出率、拡張早期僧帽弁輪最大移動速度 (e’) に2群間で有意差は認めなかった。一方、MPA群では左房径、左房容積係数が有意に高く、左室流入血流速波形 (TMF) の早期拡張期充満速度(E波)と肺静脈流入拡張期血流速度 (D波) の高さ、三尖弁における収縮期右室-右房最大圧較差も有意に高く、TMFのE波の減速時間 (DCT) は短縮していた。血清CRPはTMFのE波高、E/A比およびDCTと相関が見られた。今回の研究では、MPA患者におけるe’の有意な低下がみられなかったことから、左室弛緩能の低下よりはむしろ左室スティフネスの上昇によって左室拡張機能低下が生じ、結果として左房拡大が生じている可能性が示唆された。
結語:急性期MPA患者では左室拡張機能低下によると考えられる左房拡大を生じていた。MPA患者、特に強い炎症反応を伴う患者では、心機能評価を行うことが重要であることが示唆された。
Creators :
木下 奈津
Creators :
Tatemoto Kango
Creators :
Wu Zhenyuan
Creators :
Nur Syafiera Azreen Binti Norodin
Sleep is an essential physiological process for the human body. People spend about one-third of their lives sleeping. Both sleep duration and sleep quality are important to human health. Sleep quality describes how restful and restorative the sleep process is. Over 80 sleep disorders are known to affect sleep quality. Among them, sleep-related breathing disorder (SRBD) is the second factor. Sleep-related breathing disorders are sleep disorders in which breathing abnormalities occur during sleep. Abnormal snoring and respiratory arrest or abnormally low breathing during sleep reduce oxygen levels in the blood, increasing the risk of depression, cardiovascular disease, stroke and even death. Therefore, monitoring and analysis of respiration during sleep is gaining increasing importance in healthcare.
Polysomnography (PSG) is considered the gold standard for diagnosing sleep disorders, but PSG is usually performed in an unfamiliar sleep laboratory under the supervision of a medical technician and is often worn with many sensors that interfere with sleep. It is often the case. This research group is developing a breathing sound measurement system that constantly monitors the quality of sleep in general home environment. This system can easily measure breath sounds during sleep all night with high accuracy without disturbing sleep. The purpose of this research is to develop a technique to classify patterns of breathing sounds and to analyze the quality of breathing in order to more accurately analyze the state of sleep from breath sound information. There are various patterns of sleep breath sounds, such as normal breath sounds and snoring, and abnormal breath sounds and snoring. To develop a method to classify these patterns, to develop an algorithm to calculate ventilation from breath sounds, to estimate the sleep apnea index (AHI), and to assess the quality of breathing during sleep. try. Specifically, the temporal feature waveform (TCW) is calculated after partly removing the noise of the breathing sounds of sleep with a band-pass filter. Based on the time feature waveform, a respiratory signal effective for analysis is extracted from low-level signals and phase-divided into a respiratory phase and an apnea or low signal. Mel-frequency cepstrum coefficients (MFCC) are then obtained for the respiratory phases, and an agglomerative hierarchical clustering (AHC) algorithm is applied to distinguish between normal/abnormal breathing, normal/abnormal snoring, and normal/abnormal breathing. , tossing and turning, etc., which are less relevant to breathing. The categorized breathing patterns are analyzed every 30 seconds and the relative tidal volume of the breath is calculated. In addition to verifying the effectiveness and accuracy of the technology and analysis method proposed in this study, a method of estimating the apnea syndrome index (AHI) and converting the ventilation volume into high, medium, and low levels, We propose a method to evaluate the quality of breathing in a patient and verify its effectiveness.
This paper consists of six chapters, including an introduction and conclusion.
Chapter 1 introduces the background and overview of this research.
Chapter 2 describes a signal-processing technique for analyzing breath sounds during sleep and a method for classifying breathing patterns. Breathing sound data during sleep often includes disturbed breathing due to bruxism or body movement, ambient environmental noise, etc. In this chapter, the Time Characteristic Waveform (TCW) and the Characteristic Moment Waveform (CMW) are calculated for respiratory sound signals that have undergone preprocessing, such as filtering noise to preprocess the respiratory sounds, and the segmentation of inspiration and expiration is performed. The Mel-Frequency Cepstrum Coefficients (MFCC) are obtained for each respiratory cycle and applied as a feature vector to the Agglomerative Hierarchical Clustering (AHC) algorithm. This method is used to classify ordinary respiratory signals (normal and abnormal breathing, normal and abnormal snoring) from signals less relevant to respiration, such as tossing and turning and environmental noise.
In Chapter 3, using the technology described in Chapter 2, breathing sound data during sleep are classified into apnea, hypopnea, normal breathing, abnormal breathing, normal snoring, and abnormal breathing for each 30-second frame. In addition, we describe a method for classifying events such as no snoring and rolling over and determining the respiratory state.
In Chapter 4, we propose a method for estimating the apnea-hypopnea Apnea-Hypopnea Index (AHI) for classified abnormal breath sounds and low-level breath sound signals, compare it with the diagnostic results of PSG, and examine its validity. And verify usefulness.
Chapter 5 describes a method for estimating ventilation volume from breath sounds. Because normal breath sounds are correlated with ventilation, this study used a quantitative approach to calculate normal breathing and normal snoring and a qualitative method to calculate apnea/hypopnea and abnormal breath sounds. We will propose and compare it with the diagnosis result of PSG and verify its validity.
In Chapter 6, as an application development, an example of applying the breathing sound classification method proposed in this study to heart sound analysis is presented. Finally, we will explain the construction of a data collection distribution system for sharing auscultation data collected at different facilities and hospitals using blockchain technology.
Chapter 7 presents the conclusions and prospects of this study.
Creators :
Wang Lurui
Creators :
JARGALSAIKHAN MARGAD−ERDENE
Creators :
MEGA MIRASAPUTRI CAHYANTI
背景:The Union for International Cancer Control(UICC)の tumour、node、metastasis(TNM)分類によって大腸がんの治癒あるいは再発の可能性を予測出来るため、治療方針の決定に役立っている。しかしこの分類法単独による予後の予測は不十分である。そのため予後予測因子として新たなバイオマーカーの同定が望まれている。過去に我々は、根治切除を行ったステージI、II、およびIIIの結腸直腸がん(CRC)患者において免疫組織化学によって同定されたCD4およびforkhead box P3(FOXP3)陽性T細胞密度の組み合わせの無再発生存期間(RFS)・全生存期間に対する有用性を報告した。本研究は、統計的パターン認識の手法である離散ベイズ識別則を応用することにより、T3/T4a ステージIIのCRC患者の再発を予測するマーカーの最適な組み合わせを抽出した。
方法:T3/T4aステージII患者の137症例の切除標本を用いて、12の臨床病理学的および免疫的因子を再発の予後予測因子の候補として解析を行った。
結果:比較的に予後良好とされている T3/T4aステージ II 症例で、CD4・FOXP3陽性T細胞両方の腫瘍浸潤度に最も強い影響があることが示唆された。CD4・FOXP3陽性T細胞両方の腫瘍浸潤度が低い症例群のRFSが明らかに不良であった。
結論:CD4とFOXP3陽性T細胞を組み合わせた腫瘍浸潤度がCRCの予後予測因子となり得ることが示唆され、従来のステージ分類では不十分な患者の層別化も可能になるという新規の知見が明らかになった。補助化学療法は、CD4・FOXP3陽性T細胞両方の腫瘍浸潤度が低い患者に対して考慮されるべきであることが示唆された。
Creators :
中上 裕有樹
The development and implementation of industrial policy are essential in shaping a country’s economic landscape. It promotes industrialization, which, in turn, generates employment opportunities, enhances productivity, and diversifies the economy. the present dissertation studies the subject of industrial policy, with a particular emphasis on resource allocation and computable general equilibrium in Ghana.
Chapter 2 delves into the concept of industrial policy and its implementation in Africa in general, and Ghana, in particular. First, we examine Ghana’s past experience with industrial policy implementation and the reasons for its inability to attain the desired outcomes. Subsequently, in response to the call for a return to industrial policy, we argue in favor of a renewed implementation of industrial policy in Ghana. We posit that the likelihood of success is significantly higher with the benefit of better institutions.
Chapter 3 examines the subjects of firm-level productivity, productivity distribution, and resource allocation. In the first instance, we decompose labor productivity in Ghana and draw the conclusion that within-sector resource allocation primarily drives productivity growth, with structural change playing a limited role. Next, we analyze the gross allocative effect, finding evidence that resources are migrating toward sectors of lower productivity. Finally, we also examine productivity distribution through the lens of the power law distribution, establishing that firms involved in international trade exhibit higher levels of aggregation. Thus, allocating resources to such firms leads to greater productivity, thereby minimizing resource misallocation.
Chapter 4 presents a dynamic recursive computable general equilibrium for Ghana, employing a Social Account Matrix (SAM) with 2015 as the benchmark year, and we conclude this chapter with a brief analysis of SAM. Chapter 5 examines several possible simulation scenarios. We build our simulations around two industrial policy strategies: labor-intensive and capital-intensive, furthermore our simulation is informed by Ghana’s industrial policy plan. We analyze various policies such as efficiency improvement, trade protection, free trade, and taxation policy.
We conclude that capital-intensive industrialization would work better under a free trade policy. Moreover, we discovered that the cost of protecting labor-intensive industries is less than the cost of safeguarding capital-intensive industries. We conclude the dissertation with a discussion of the implications of our findings. we aim to provide a comprehensive discussion of the implications of our findings, as well as acknowledge the limitations of our study and propose potential avenues for further research. By doing so, we hope to contribute to the existing body of knowledge in our field and inspire future researchers to expand upon our work.
Creators :
Borges Jorge Tavares
本研究では、小児期(幼児期、学童期、青年期)の生活習慣、遺伝要因と肥満との関連を調査し、肥満予防のための公衆衛生的アプローチを検討した。食物繊維摂取が学童期の子どもの肥満および血圧、血中脂質パラメーターに及ぼす影響を明らかにすること(調査1:10~11歳の横断研究)、FT0遺伝子多型が幼児期から青年期の体格変化に及ぼす影響を明らかにすること(調査2:3歳、10歳、13歳に渡る縦断研究)、さらに、学童期から青年期にかけて身体活動がFT0遺伝子多型と体格変化に及ぼす影響を明らかにすること(調査3:13歳、18歳に渡る縦断研究)、を本研究の目的とした。
調査1では、学童期の食物繊維摂取は肥満およびコレステロール高値のリスク低減に有効であることが示唆された。
調査2では、幼児期から学童期にかけてFT0遺伝子の影響が強く表れ、中学生の年代になるとこの影響は逆に減弱し、部活動等が始まるこの時期の身体活動の影響が関連している可能性があることが推測された。
調査3では、青年期で、身体活動量が多いほどBMIの増加を弱め、FT0遺伝子多型の影響を減弱させた。
本論文の構成は5章からなる。
第1章では、緒言として、研究の背景と本研究の目的を述べる。
第2章では、食物繊維摂取が学童期の子どもの肥満および血圧、血中脂質パラメーターに及ぼす影響を検討した。
第3章では、FT0遺伝子多型が幼児期から青年期の体格変化に及ぼす影響を検討した。
第4章では、身体活動がFT0遺伝子多型と体格変化に及ぼす影響について検討した。
第5章では、結言として、本研究のまとめと今後の研究の方向性、今後の展望を述べた。
Creators :
木村 圭子
Fault geometry and the geotectonic evolution of the median tectonic line in Shikoku, southwest Japan
中央構造線(MTL; Median Tectonic Line)は、西南日本を東西に横断する延長約1000kmの断層である。愛媛県西条市付近には、MTLは三波川変成帯と和泉層群を境する構造線としての低角度な断層帯(MTLTB; MTL inactive terrane boundary)と、この断層の北側に並走する活断層としての高角度な断層帯(MTLAFZ; MTL active fault zone)がある。地表でのMTLAFZの傾斜角度を明らかにするために、川上断層を横断する延長約10m、深さ約2mのトレンチ調査を行った。また、地表部で約10mの間隔で並走する両断層の地下での接合関係と断層面の傾斜角度を明らかにするために、断層を横断する80-330mの6本のボーリング掘削を実施した。更に、より広範囲の断層構造や地盤の物性を把握するために延長1200mの反射法地震探査と延長500mの高密度電気探査を実施した。採取した断層試料を用いて断層岩の化学分析、変形構造記載、カルサイトの双晶密度の測定、断層の変形フェーズの解析を行い、低角度横ずれ断層のメカニズムや断層活動史を明らかにした。
トレンチ調査、ボーリング調査、高密度電気探査により、地表部で北方へ約70゜の角度で傾斜する川上断層が、地下で北方へ30゜の角度で傾斜するMTLTBに収れんすることが示唆され、地下のMTLTBは活断層であることが分かった。MTLTBの上盤に分布する小断層の卓越した和泉層群の比抵抗値は、主破砕帯の割れ目の少ない安山岩ブロックと推定される高比抵抗部を除き、断層下盤に分布する堅硬な三波川変成岩類の比抵抗値よりも低い値を示した。また、断層に沿って深部流体が上昇していると推定される低比抵抗帯が確認された。反射法地震探査では、MTLTBに相当する北方へ約30゜の角度で傾斜する明瞭な反射面が確認され、より深部まで断層が延長することが分かった。主破砕帯を構成する蛇紋岩中の鉱物のEPMA分析結果によると、マントル起源のマグネシオクロマイトを含むことが分かった。既往の深部地震探査の結果は、MTLの深部延長が下部地殻まで達しいることを示しているが、これにより、MTLTBの延長がマントルまで達し、蛇紋岩が断層変位とダイアピルによって表層部まで上昇してきたことが示唆された。MTLTBは断層面の傾斜角度が低角度であり、本来は横ずれ断層として動きにくいと考えられる。MTLTBの断層ガウジや主破砕帯に大量の層状珪酸塩鉱物が存在することや断層沿いの深部流体の存在は、断層のせん断強度を低下させる要因となり、低角度の断層でも横ずれ運動が可能になったと考えられる。カルサイトの双晶密度から求めたMTLTBを横断する歪み分布は断層から直線的で緩やかに低下する傾向を示し、断層のせん断強度が低下していることを示唆する。
変形フェーズの解析では、MTLTBとMTLAFZの幾何学的な特徴やそれぞれの断層と地層との接合関係、断層の変位センス等の構造地質学的特徴、古応力場の解析等に基づいて変形フェーズを古いほうからD1~D4の4つに定義した。D1フェーズはNNE-SSW圧縮の応力場の変形であり始新世中期(47 -46 Ma) 頃に断層の上盤が西方へ変位した左横ずれセンスの運動、D2フェーズはE-W伸張の応力場の変形であり中新世中期(15 -14 Ma) 頃に断層の上盤が北方へ変位した正断層センスの運動、D3フェーズはNNW-SSE圧縮の応力場の変形であり中新世中期から鮮新世後期(14-3Ma) 頃に断層上盤が南方へ変位した逆断層運動、D4フェーズはWNW-ESE圧縮の応力場の変形であり鮮新世後期から更新世前期(3-1 Ma) 以降に断層上盤が東方へ変位した右横ずれ運動である。
西南日本を横断する中央構造線沿いには多くの都市が分布しており、MTLの傾斜角度等の幾何学的な情報は、地震災害分布や地震の規模等を予測する上で重要パラメータになると考えられる。また、MTLAFZは地下数km以内の浅い深度でMTLTBに収れんすると考えられ、従来、非活動的な地質断層として考えられていたMTLTBが、将来、活断層として変位する可能性があることを示唆している。
Creators :
Miyawaki Masahiro
Access to clean water has been crucial global problem, especially with climate change, increasing population, and industrial activities. As one of Malaysia’s leading economic activities, the Oil and Gas Industry generates a massive amount of wastewater called Produced Water (PW). Dissolved organics in produced water, such as organic acids and phenolic compounds, are concerning due to the possibility that they can be toxic, non-biodegradable, and have bioaccumulation properties. Conventional treatments such as adsorption, incineration, and biological treatment seem to have difficulties treating these dilute but toxic components in an economical and environmentally friendly manner. Regulations on wastewater management has also been stricter around the globe. Therefore, there is a need on a new water treatment method to treat the diluted organics in a large volume of wastewater.
Membrane technology has been of interest in the water treatment technologies’ industrial and research scenes. It offers simpler configuration and maintenance. However, the application is limited by the reduction of performance over time due to fouling phenomena. Photocatalyst offer an effective method to decompose organics in an environmentally friendly manner. This study researched on photocatalytic removal of diluted organic in water and potential of biofouling reduction by deposition of AgTiO2 coating on membrane surface.
In Chapter 1: Introduction, the research background and purpose of this research were
discussed. At the end of this chapter, the thesis framework was shown.
In Chapter 2: Preparation and characterization of TiO2 and AgTiO2 coatings; the method to prepare AgTiO2 coatings on membrane support were explained. The prepared membranes were characterized with XPS, SEM, TEM, and ICP analysis to understand the prepared coatings. Results shows that the concentration of silver deposited on the membrane can be control by the concentration of silver in the precursor (silver acetate solution) used during the photochemical deposition step. Via XPS, it was found that the state of silver prepared through this method is oxide state.
In Chapter 3: Removal of dissolved organic pollutants in water by photooxidation, the photocatalytic performance of prepared membranes was studied. Decomposition of diluted formic acid was performed under UV-light, and the concentration was evaluated using UVspectrophotometer. AgTiO2 membranes show better photocatalytic activity then TiO2 membrane. The concentration of silver on the membrane was found to influence its photocatalytic performance. In relation to PW application which commonly contain high salts, influence of salt types; NaCl, MgSO4, MgCl2 and K2SO4 and concentration were studied. All salts were found to inhibit the membranes’ photocatalytic performance.
In Chapter 4: Antibacterial activity of AgTiO2 membranes, the antibacterial activity towards E. coli by prepared AgTiO2 membranes were investigated. Silver dissolution from membrane was found to be significantly increased in the presence of NaCl as compared to only water. Comparing membrane with lower Ag deposition, and around 20 times higher deposition, the silver dissolution from these membranes reached almost the same value after some time. However, as the amount of silver deposited on the membrane was higher, the antibacterial performance show around four times higher than the lower silver membrane. Based on other tests performed, it was concluded that there are potential of contribution from the silver oxide deposited on the membrane surface on the antibacterial activity of the AgTiO2 membranes
In Chapter 5: Antibacterial activity in filtration system, prepared AgTiO2 membrane was used to filter E. coli suspension in water. E. coli growth was found to be inhibited by short contact with silver on the coated membrane.
Finally, Chapter 6: Conclusion, the thesis was summarized, and future works were proposed.
Creators :
Azzah Nazihah binti che abdul rahim
Creators :
Fukushima Kuniharu
Innovation is the practical implementation of ideas that result in the introduction of new goods or services or the improvement in them (Schumpter, 1983). Innovation is closely related to invention as innovation is more on involving the practical implementation of a new or improved invention to make a meaningful impact in a market or society (Schumpter, 1939). On the other hand, innovative design is a process of identifying, pinpointing, and understanding the needs of the user or audience (Shaulis, 2021). Previously, Dixon (1966) defined innovative design as any design that is: new or different, or elegant or uses new ideas, or is an improvement over its peers. Once the market need has been identified, a solution can then be designed. In our proposed innovative design method, we introduced and investigated a method that is able to be applied in designing an intergrated system that could be a valuable solution to the society. This method starts with directly observe activities of things and real people in real trouble in the real field. Then, we think about the value of "I wish there were such things as…", visualize the story, draw a clear sketch to accomplish the story concretely. Next, we solidify the functions and specifications while investigating needs and competition. Then, we create a prototype that able to show and test your ideas, demonstrate to the people who need it, let them experience it, and gain feedback. Lastly, we evaluate the value of product design and development and plan methods for implementing it as an organization, and plan ways to improve and expand globally. All of the steps in this method are important for innovative design, however, in this research this time we focused on co-designing value, big idea, and considering as integrated steps for identifying latent needs of the consumers. It is because identifying needs is an important part in the product development process.
Latent needs are those that many consumers recognize as important in a final product but unable to articulate in advance (Ulrich, 2015). The latent needs addressed in this study was focusing on identifying consumer requirements in product development in the innovative design method. The challenge in identifying latent needs is finding the method to elicit from consumers the needs which are not addressed by any inventors yet in the present market but would delight the consumers if delivered tomorrow. The purpose of this study is to propose and verify the method in the elicitation of latent needs from consumer needs by introducing a working prototype to the consumers, interviewing, and analyzing responses from the consumers.
This research was conducted during the year the start of the COVID-19 pandemic. As the pandemic spread, most countries were forced to go into lockdown or declare an emergency state. The school was closed and business organizations needed to switch to working from home to prevent the spread. The parents were unable to work from home efficiently as they were worried their children will involve in dangerous incidents if the children were left by themselves. Based on this situation, this study was conducted in finding the latent needs of the parents, childcare workers, and children in order to assist them in going through their problems during this COVID-19 pandemic.
The working prototype was used as material to prepare presentation slides for the consumers' interviews. The first presentation slides were focused on the background problems and ideas for the solutions while the second presentation slides provided consumers with a prototype and story of the product that was believed would be one of the solutions to the problems. Interviews were conducted after both slide presentations. Consumers' responses were obtained and interpreted into consumers' needs in terms of product functions.
In the first study, consumers' interpreted needs from Problem-based interviews and Prototype and Story-based interviews were compared. Based on the results, latent needs interpreted from interviewees' responses and the categories of the needs obtained from the Prototype-based interviews are more than from the Problem-based interview. The latent needs that we were able to obtain from this research were for example, “The device is able to detect small changes in a child while watching he/she sleeping” which could lead into the prevention of unwanted incident such as sudden infant death syndrome (SIDS). This supports our assumption that showing working prototype-based materials with story descriptions can be effective in uncovering potential latent needs.
In the second study, it is assumed that experience, empathy, and knowledge of working prototype is essential elements in product development, therefore, new additional guidelines which are “to write a statement with empathy”, “to write a statement as a designer”, and “to write a statement as someone with experience” were proposed during consumers' needs interpretation to see whether these new guidelines will influence the process of identifying latent needs of consumers. From the result, it is concluded that the number of interpreted needs increased when we applied the new proposed guideline. Although the number is small, the needs might not be interpreted if the new guidelines were not considered. We were also able to obtain a few important latent needs when we applied these new guidelines. A latent need collected from applying the guideline "to write a statement as someone with experience" is “The device is not for teaching love and humanity but for monitoring by watching facial expression, posture, and vital signals such as temperature and heart rate”. We could conclude that including these guidelines upon interpreting raw data from the consumers’ interviews might lead into discovering important and critical latent needs of the consumers.
In the third study, a quantitative evaluation method for identifying latent needs was introduced. The consumers' interpreted needs were rated according to a basis of rating from the three perspectives of importance, latent-ness, and technological feasibility. The Degree of Latent Needs (DLN) was calculated by multiplying these three metrics. Based on the result for the average and variance of DLN mean value for each evaluator which is sufficiently small, it indicates that the basis of rating for three metrics of the DLN is effective. The results also indicate that the 20 highest DLN points of the interpreted needs contain attractive features in terms of design. However, we had gotten some pushback on the average of each interpreted need and its variance which indicates opposing opinions among evaluators. As it is possible that attractive needs are hidden and may lead to the discovery of latent needs through individual pinpoint interviews, the interviews with the minority evaluators were conducted. The interview results indicate that the latent needs with low DLN rates but valuable might be able to be discovered by conducting follow-up interviews such as “The device is able to recognize items (food or not) that a child wants to put in the mouth”. From the results in all three studies, we could conclude that a number of important latent needs are able to be elicited from consumers’ needs by applying the proposed method. In our fourth study, a decision-making method based on the patent analysis between the conceptual design stage and the prototyping stage in the innovative design method was introduced. Conducting a patent strategy was assumed to support how to select the right concept precisely. In this study, by conducting a patent search in this stage by the designer who understood best the product functions and working principles, a supporting method was introduced to assist the designer in their decision-making process. Based on the result, the method was able to observe whether there are dominating companies or not for our concept design. If there is a dominating company, the possibility of not being able to produce our concept becomes bigger. This method may be applied as an indicator to support decisionmaking in the concept design stage in the innovative design method, whether to proceed with the concept design or not and to reduce the possibility of product failure in the future.
From the results of all the studies, we could conclude that these above methods may be applied as assistive tools to support designers’ understanding of consumers’ requirements and selecting the right concept design.
Creators :
Nurhayati Binti Md Issa
Creators :
Kawasaki Minae
背景:肝癌は肝内転移を生じやすく、その予後は不良である。がん幹細胞様細胞(CSLCs)とは、幹細胞性、腫瘍形成能、治療抵抗性に加え、転移能亢進といった特徴を有している。近年では、がんの転移形成や制御において、宿主の免疫機構が重要な働きを担っていると考えられており、今回、肝癌細胞株から誘導したCSLCsの免疫逃避能について検討を行った。
方法:Sphere誘導培地を用いて、Sphere細胞の形態で肝癌細胞株からCSLCsを誘導した。免疫逃避に関わる遺伝子およびタンパク発現を、RNAシーケンス、フローサイトメトリー、ELISA法を用いて解析し、親株とSphere細胞とで比較した。親株とSphere細胞それぞれの、NK細胞に対する感受性について、クロム放出試験を用いて比較検討した。BALB/cヌードマウスを用いた異種移植実験にて、親株とSphereの腫瘍形成能を比較した。
結果:肝癌細胞株SK-HEP-1から誘導したSphere細胞(SK-sphere)では、親株と比較し、細胞膜上のPD-L1、PD-L2、CEACAM1の発現が亢進し、ULBP1、MICA/MICBの発現は低下していた。また、SK-sphereの培地中では、可溶型MICAの濃度が上昇していた。SK-sphereにおけるHLA class I発現低下は見られなかった。肝癌細胞株SK-HEP-1およびHLEから誘導したSphere細胞を用いて、NK細胞に対する感受性をそれぞれの親株と比較したところ、どちらのSphere細胞においてもNK細胞による細胞障害性がより低下していた。NK細胞を保持するヌードマウスにおいて、親株の移植と比較してSK-sphereを移植した際により大きな腫瘍を形成した。
結論:肝癌細胞株から誘導したCSLCsはNK細胞を介した免疫系からの逃避能が亢進している事が示唆された。
Creators :
木村 祐太
Creators :
Chaiyasing Rattanatrai
Nutrient pollution is one of our most pervasive, expensive, and challenging environmental problems, according to the United States Environmental Protection Agency (EPA). Phosphorus is one of the nutrients that are essential for the growth of living organisms. However, excessive amounts of nutrients released into the environment by human activities can harm ecosystems and impact human health. In surface waters, phosphorus can contribute to an overgrowth of algae called algal "blooms" that can sicken or kill wildlife and endanger aquatic habitats. Algal blooms consume dissolved oxygen in the water, leaving little or no oxygen for fish and other aquatic organisms. Algal blooms can harm aquatic plants by blocking the sunlight they need to grow. Some algae produce toxins and encourage the growth of bacteria that can make people sick who are swimming or drinking water or eating contaminated fish or shellfish. Phosphorus is often a major limiting nutrient freshwater system. Consequently, many of the wastewater treatment plant discharged into freshwater systems such as lakes, ponds, and rivers have phosphorus discharge limits. In an attempt to prevent harmful environmental effects of excess phosphorus, several techniques have been designed to remove phosphorus from wastewater. These techniques range from adsorption and precipitation to enhanced biological phosphorus removal and constructed wetlands.
Biological phosphorus removal (BPR) was first used at a few water resource recovery facilities in the late 1960s. A common element in EBPR implementation is the presence of an anaerobic tank (no nitrate and oxygen) before the aeration tank. In the next aerobic phase, these bacteria can accumulate large amounts of polyphosphate in their cells and phosphorus removal is said to be increased. The group of microorganisms that are largely responsible for P removal are known as the phosphorus accumulating organisms (PAOs).
One of the options to remove phosphorus is to utilize bacteria from nature, besides being easy to obtain and inexpensive. The application of bacteria from sediment and seawater was able to reduce phosphorus in wastewater. In this study, for screening salt-tolerant phosphorus accumulating organisms (PAOs) and investigating the P release and uptake of the organisms in saline wastewater. The samples used were sediment and seawater from Yamaguchi Bay, Yamaguchi, Japan. Sediment and seawater added 150 mL of artificial saline wastewater with media (anaerobic media). The samples were then cultured and given feed media every three hours day at 25 °C and shaken at 140 rpm. The hydraulic retention time of the cultivation was 16 h and 8 h under anaerobic and aerobic conditions, respectively. 10 sponges made of polyurethane with dimensions of 2 cm were put in Erlenmeyer flasks and was used as a bio-carrier surface for microorganisms to adhere to. Water was passed over the sponge surface to acclimatize the microorganisms growing outside the sponge as well as within its pores, ensuring sufficient growth surface. The cultivation duration was 112 days. Batch experiments were conducted over 98 days in solutions with a salinity of 3.5% and P concentrations of 1, 5, 10, and 20 mg-P/L. The P-uptake ability of microorganisms increased by increasing P concentration from 1 to 20 mg-P/L. A high P removal percentage with an average of 85% was obtained at 10 mg-P/L after day 56. The uptake and release of P were observed in saline wastewater, signifying that salt-tolerant PAOs could grow in the saline solution. Bacterial screening by isolation and sequence analysis using 16S rRNA demonstrated that two cultivated strains, TR1 and MA3, had high similarity with Bacillus sp. and Thioclava sp. EIOx9, respectively. The colony morphology analysis showed that the colonies of TR1 were rod-shaped, milky-colored, round, shiny-viscous, smooth with a defined margin, while colonies of MA3 were cream-colored with smooth surfaces and raised aspect. The TR1 was gram-stain-positive with approximately 6-10 μm long and 1.2 μm wide cells, and MA3 was gram-stain-negative with about 0.9 μm long and 0.5 μm wide cells. The results demonstrated the involvement of Bacillus sp., and Thioclava sp. in the release and uptake of P, owing to their ability to grow in saline wastewater.
Furthermore, Bacillus sp. (TR1) and Thioclava sp. (MA3) were assessed for their abiotic adaptability and phosphorus removal efficiency in saline wastewater. The effects of abiotic factors such as carbon source, pH, temperature, and salinity on bacterial growth were examined through a series of batch experiments. Both bacteria used carbon sources such as glucose, sucrose, and CH3COONa for their growth. The pH study indicated that Bacillus sp. (TR1) preferred the pH range of 6 8 and Thioclava sp. (MA3) preferred the pH range of 6-9. Bacillus sp. favorably multiplied in the temperature range of 25- 40 °C, while 25 35 °C was preferred by Thioclava sp. Salinity range of 0% 10% was favorable for TR1, with optimum growth observed at 3.5% 5%, and Thioclava sp. (MA3) preferred the salinity range of 1% 10% with optimal growth at 4%, but was absent in non-saline water. Bacillus sp. and bacterial combination (TR1 and MA3) showed similar values for phosphorus removal efficiency (100%) at 1.0 mg-P/L total P compared to Thioclava sp. (38.2%). The initial phosphorus concentration of 2.5 mg-P / L showed a slightly higher 72.35% P removal efficiency compared to the individual strains. However, phosphorus removal did not increase, but showed a downward trend with increasing at initial phosphorus. The combination possibly built a synergistic activity between the individual strains to remove phosphorus. The results demonstrated that when used individually, Bacillus sp. showed a reasonably high phosphorus removal ability than Thioclava sp., and exhibited good synergy when used in combination to remove phosphorus from saline wastewater.
Creators :
Hasanah Rafitah
自動車事故に際しシートベルトに沿って生じる帯状の皮下出血斑はシートベルト兆候(seat belt sign:SBS)と呼ばれている。特に腹部SBS が上前腸骨棘(anterior superior iliac spine:ASIS)よりも上方に位置する場合、腹部臓器損傷の危険性が高い。本研究の目的は、腹部SBS 位置に関連するシートベルト腹部部分(ラップベルト)の位置に影響を与える因子について解析することである。本研究は、健康な成人100名(男性50名、女性50名)の身体所見と、カーシート座位時のラップベルト位置との関係を前向きに検討したものである。身体所見は、年齢、身長、Body Mass Index(BMI)、腹囲を測定した。それぞれ平均年齢37.9歳、平均身長164.9cm、平均BMI 23.9kg/m2、平均腹囲83.4cmであった。X線学的所見は、腰椎前弯(lumbar lordosis:LL)、仙骨傾斜(sacral slope:SS)を測定し、ラップベルト位置は運転席側のラップベルトの中央とASIS相当の位置に鉛テープでマーキングすることで計測した。側面X線撮影を行い、ASISから中央マーカーまでの水平距離(X値)、垂直距離(Z値)を計測した。ラップベルト角度は、2つのマーカーの上端を結ぶ直線と水平線とのなす角度を計測することで求めた。これらの身体所見とX線学的所見との関係を統計学的に解析した。X値とZ値は体重(X値r = 0.73、Z値r = 0.56)、BMI(X値r = 0.77、Z値r = 0.56)、腹囲(X値r = 0.74、Z値r = 0.52)と正の相関があり、ラップベルト角度は体重(r = -0.33)、BMI(r = -0.35)、腹囲(r = -0.37)と負の相関があった。これらの結果からは、BMIの高い乗員ではラップベルトがASISより高い位置にあるため、シートベルト損傷を引き起こす可能性が高い。この解析は、より安全なシートベルトの開発に役立つと思われる。
Creators :
山縣 大樹
Creators :
Putu Ayu Asty Senja Pratiwi
Creators :
ZHANG YUNJIN
近年、遺伝子改変T細胞を用いた養子免疫療法の臨床応用が進められているが、未だ治療成績は満足のいくものではなく、更なる治療の進歩が求められている。我々はこれまで、自律性にIL7とCCL19を発現するCAR-T細胞(7×19 CAT-R細胞)が優れた抗腫瘍活性を発揮することを示した。本研究ではIL7及びCCL19がTCR-T細胞の抗腫瘍活性を増強させる可能性を検証するため、腫瘍抗原であるP1Aを特異的に認識するTCR-T細胞(P1A-T細胞)にIL7及びCCL19を分泌させる遺伝子改変を加えた7×19 P1A-T細胞を作製した。P1Aを有する細胞株であるP815を皮下接種したマウスに対する養子免疫療法において、7×19 P1A細胞はIL7及びCCL19を分泌しないP1A-T細胞(Conv. P1A-T細胞)と比較し優れた抗腫瘍効果を示した。腫瘍拒絶マウスにおいては、Conv. P1A-T細胞を使用したマウスと比較し優れた免疫記憶が形成されていた。また抗PD-1抗体を用いた複合免疫療法を行うことで、7×19 P1A-T細胞の有する抗腫瘍効果は更に増強された。CRISPR/ Cas9システムを用いPdcd1をknockdownした7×19 P1A-T細胞は対照7×19 P1A-T細胞と比較し強い抗腫瘍効果を示したが、抗PD-1抗体を併用することで更なる抗腫瘍効果の増強を認めたことから、7×19 P1A-T細胞の発揮する抗腫瘍効果には7×19 P1A-T細胞そのものばかりでなくマウス内在性のT細胞が関与していることが分かった。また、7×19 P1A-T細胞においても抗PD-1抗体との併用により抗腫瘍効果が増強することを確認した。本研究における検証により、7×19 TCR-T細胞及び7×19 CAR-T細胞を用いた免疫療法が抗悪性腫瘍療法の発展に寄与できる可能性が示された。
Creators :
德永 良洋
現在の日本は少子高齢化・医療高度化を背景に、要介護者数の増加、医療費増加、人材不足、医療格差などの医療課題に直面している。近年、人工知能(ArtificialintelligenceAI)技術やシステム医学に基づいたデータ駆動型医療の登場によって、これら課題を解決できる可能性が広がった。筆者自身は呼吸器診療に携わる立場でもあることから、呼吸器診療を支援する以下3つの医療AI技術を開発した。1つ目の技術では、副作用ビッグデータ(JapaneseAdverseDrugEventReportJADER)に基づきベイズ推定を行うことで、AUC0.93の精度で副作用の原因薬を推定できた。呼吸器領域では薬剤性肺障害など重篤な副作用があるが、本技術の臨床応用によって、副作用による健康被害の最小化と副作用管理の効率化が期待できる。2つ目の技術では、喘息患者の臨床データ(年齢、BMI、血中好酸球数、呼気NO値、増悪回数)をもとに教師あり機械学習を行うことで、喘息患者の気流閉塞の急速進行1秒量低下)をAUC0.85の精度で予測できた。実用化によって、早期の治療介入が必要な喘息患者を同定でき、重症化を防ぐための先制治療につながる。3つ目の技術では、喘息質問票(AsthmaControlQuestionnaire-5:ACQ-5)のデータを用いて教師なし機械学習を行うことで、症状から喘息病態である気流閉塞、2型気道炎症、増悪リスクを推定できた。従来、治療選択のため病態評価には専門的検査が必要だが、本技術ではACQ-5に含まれる喘息症状の評価のみから、個々の喘息の病態に応じた治療選択(個別化治療)につなげることができる。本技術は、発展途上国、過疎地域、プライマリケアの現場など、医療環境が不十分な地域で、適切な喘息治療薬の選択を支援できる。ひいては、医療格差の是正につながる可能性が期待できる。本研究で開発したAI技術の実用化によって、臨床現場における副作用管理、先制医療、個別化治療を支援する。これによって、健康寿命の延伸、医療費抑制を目指す。同時に、開発したAI技術によって専門医療の一部を補完することで、医療従事者の業務負担軽減と、医療格差の是正均てん化につながることが期待できる。
Creators :
濱田 和希
【目的】代謝状態の朝晩の変化を理解することは、代謝障害を管理するためには重要である。我々は、インスリン分泌とインスリン感受性の観点からこの朝晩の変化を解析し、さらに概日リズムとの関連性を含めて検討することを目的とした。
【方法】非糖尿病成人男性14人と10人に対し、それぞれ75g経口ブドウ糖負荷試験(OGTT)と高インスリン正常血糖(HE)クランプ実験を行った。各被験者に対し、午前8時と午後8時にOGTTまたはHEクランプを1回ずつ行った。ただし試験時間の順序は無作為とした。各試験直前に毛根を採取し、毛包における時計遺伝子発現量をリアルタイムPCR法で解析した。また、マウスの肝臓と筋肉でもAKTリン酸化をウエスタンブロット法により解析した。
【結果】OGTTの結果から、耐糖能は午前8時の方が良好であることがわかった。これは、OGTTにおける負荷後60分までのインスリン早期分泌とHEクランプで説明される骨格筋インスリン感受性の違いに起因すると考えられた。一方、OGTTにおける肝臓のインスリン抵抗性指数によって推定される肝インスリン感受性は、午後8時の方が良好であった。60分までのインスリン分泌量と肝臓のインスリン抵抗性指数の朝晩の差は、Per2のmRNAの相対的発現量と有意に相関していた。ΔGIR(20時の値-8時の値)は、Δ非エステル化脂肪酸(NEFA)と有意に相関したが、時計遺伝子発現との相関は認められなかった。ΔNEFAは、E4bp4のmRNA発現量およびΔコルチゾールと有意に相関していた。マウスでは、ヒトの研究から予想されるように、AKTリン酸化は活動時間の初めに肝臓で減少し、筋肉で増加していた。
【結語】各組織の糖代謝は朝と晩で大きく異なっており、脂質代謝、時計遺伝子およびコルチゾールの影響を受けていることがわかった。この関連性についてのより深い知見が代謝障害の新たな改善法の開発に寄与する可能性がある。
Creators :
藤本 留理子
膵β細胞量の進行性の減少が糖尿病の発症・進展に関与する。糖尿病病態では、インスリン作用不足による高血糖に対する代償的なインスリン産生の増加や脂質異常のためにβ細胞において小胞体ストレスが亢進する。一方、セリン・スレオニンキナーゼGsk-3 はPI3/Akt により抑制され、Gsk-3 の活性制御障害がβ細胞不全と小胞体ストレス関連β細胞死に関連する。しかし、Gsk-3 を介した細胞障害の分子機構は十分に解明されていない。本研究では、Gsk-3 を介する小胞体ストレス応答調節と膵β細胞アポトーシス誘導の関連について検討を行った。方法:マウス単離膵ランゲルハンス氏島(ラ氏島)およびマウス膵β細胞株で薬理学的に小胞体ストレスを誘導した。Ins2 遺伝子に変異を持ち、変異インスリンの蓄積により小胞体ストレスが亢進しβ細胞死を来すAkita mouse 由来の膵β細胞株を遺伝的小胞体ストレスのモデルとして用いた。低分子化合物、あるいは酵素不活性型Gsk-3βの導入によりGsk-3 活性を阻害した。結果:小胞体ストレス下ではGsk-3 を抑制するAkt の活性が減弱しGsk-3 が活性化した。Gsk-3 はATF4 のSer214 リン酸化を介してATF4 とSCF-βTrCP の結合とそれに続くATF4 のユビキチン化、蛋白分解を促進する。したがって、Gsk-3 の抑制によりATF4 の分解速度が低下し、ATF4 蛋白質量が増加することが明らかになった。このとき、β細胞のアポトーシスが減弱することを確認した。この抗アポトーシス効果はdominant negative-ATF4 導入あるいはATF4 ノックダウンにより有意に減弱した。Gsk-3 抑制によるアポトーシス抑制のメカニズムについて、ATF4 の転写標的であるGADD34 および4E-BP1 の発現増強を介した全般的な蛋白翻訳の動態との関連が考えられた。さらに、Akita mouse 由来の膵β細胞株でもGsk-3 活性阻害によるアポトーシス抑制が確認され、これにはATF4 の発現増強と全般的な蛋白翻訳抑制が関連した。以上の結果より、インスリンシグナルとストレス応答のクロストークが明らかになり、Gsk-3/ATF4 経路が糖尿病におけるβ細胞保護の治療標的となる可能性が示唆された。
Creators :
永尾 優子

