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Biological analyses of transcriptional regulators in Drosophila
Get PDF京都工芸繊維大学博士（学術）Gene expression is accurately and dynamically modulated by various mechanisms including epigenetic regulation and transcription DNA to RNA. These regulations are fundamental mechanism for development, tissue homeostasis and behavior. 1. Functional analysis of Smallish during Drosophila development Smallish (Smash), the Drosophila homologue of human LMO7, was reported as a key regulator of Drosophila embryogenesis associated with actomyosin contractility. Although smash mRNA is expressed throughout Drosophila development, only Smash function at the adherence junction in embryonic epithelial cells has been revealed. Here, I demonstrated that the eye imaginal disc-specific smash knockdown induced eye morphological aberrations associated with increased apoptosis. Moreover, immunohistochemical analyses revealed that Smash mainly localized to the nucleus in several tissues, including eye imaginal discs. As is the case with LMO7, the smash knockdown in eye imaginal discs decreased the expression of the ote and bocks genes known as the Drosophila homologue of the emerin gene. Furthermore, down-regulated ote and bocks expression induced apoptosis. Taken together, these results indicate that Smash functions in proper Drosophila eye development mediated by the regulation of ote and bocks gene expression.2. G9a is a key regulator of the starvation-induced behaviors in Drosophila melanogaster Organisms are exposed to starvation stress in nature. In spite of the importance of behavioral strategies under the starvation, the underlying mechanisms have not been fully understood. Here, I revealed that Drosophila G9a (dG9a), one of histone methyltransferases, plays a key role for the starvation-induced behaviors. RNA-seq and RT-qPCR analysis revealed that the expression of gustatory receptor genes for sensing sugar are increased in dG9a null mutant under the starvation condition. Consistent with its up-regulation, proboscis extension reflex tests indicated that the sucrose sensitivity under starvation conditions was significantly increased. Moreover, the locomotion activity was promoted in starved dG9a null mutant. This hyperactivity is caused by down-regulation of insulin-like peptide genes expression under the dG9a depletion, which genes are required for the suppression of starvation-induced hyperactivity. Moreover, refeeding of wild type flies after starvation conditions restores these phenotypes. These data suggest that dG9a functions as a key regulator for the decision of behavioral strategies under starvation conditions
Controlled Synthesis of Glycopolymer-type Macromonomers and their Use for the Preparation of Carbohydrate-Decorated Polymer Particles
Get PDF京都工芸繊維大学博士（工学）Macromonomers containing one or more polymerizable groups in the polymer chains have been recognized as useful building blocks of various polymer assembly architectures. Among them, the use of amphiphilic macromonomers for the dispersion or emulsion copolymerization with hydrophobic monomers in polar media can produce polymer particles of a wide range of sizes. The resultant polymer particles are categorized as hairy or core-shell particles and hence afford stable aqueous dispersions, where the dispersion stability is attributed to the steric stabilization attained by the hydrophilic polymer chains fixed on the particle surfaces. It is worth noting that the surface functionality of the particles can be widely designed by varying the structure of the macromonomers because the polymer chain moieties are covalently attached to the particle surfaces. In particular, polymer particles decorated with carbohydrates on their surfaces have been of great interest in the biomedical field, because they have potential ability for providing useful materials for diagnosis based on their specific interactions with biomolecules such as proteins and viruses etc. In order to produce carbohydrate-decorated polymer particles, the author designed novel amphiphilic glycopolymer-type macromonomers, which are synthesized by controlled polymerizations, thereby possess well-defined architecture consisting of pendant carbohydrate moieties and a terminal vinyl group. Moreover, chain lengths of the macromonomers and composition ratios of the block copolymer-type versions can be precisely controlled. This thesis deals with the following research topics: (i) The synthetic strategies for yielding various glycopolymer-type macromonomers were developed. Firstly, a combination of living cationic polymerization of alkyne-substituted vinyl ether (VEEP) and copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) allowed the poly(vinyl ether) (polyVE)-based glycopolymer-type macromonomers, where the precursor macromonomer having pendant alkynes and a methacryloyl group at α-terminus was synthesized by living cationic polymerization of VEEP, followed by CuAAC click reaction with maltosyl azide. The resultant glycopolymer-type macromonomer possesses both pendant maltose residues and a terminal polymerizable group at α-end. (ii) The synthetic methodology in (i) was then applied for the synthesis of amphiphilic glycopolymer-type macromonomers composed of a hydrophobic poly(alkylVE) segment and a maltose-substituted hydrophilic polyVE segment. Through the dispersion copolymerization with styrene in polar media, this amphiphilic macromonomer afforded core-shell polymer particles decorated with maltose residues on their surfaces. (iii) An alternative approach for the synthesis of glycopolymer-type macromonomers was developed based on the living radical copolymerization by RAFT (reversible addition-fragmentation chain transfer) process of maltose-containing and other acrylamides and subsequent functional conversion of the terminal function. The precursor maltose-carrying polyacrylamide was successfully synthesized by RAFT copolymerization, and its terminal trithiocarbonate function was reduced and then subjected to thiol-ene reaction with a diacrylate compound to give the target macromonomer. The obtained macromonomer possess both pendant maltose residues and an acryloyl group at ω-end, and was found to be capable of forming maltose-decorated core-shell polymer particles by dispersion copolymerization with styrene in polar media. (iv) Lectin binding assay using concanavalin A (Con A) revealed that the prepared maltose-decorated polymer particles specifically interact with Con A
はじめに――空間イメージとその変容
Get PDF空間が感性の形式として、対象とは異なる所与性をもつことの確認から始め、それゆえ起こる空間のイメージの多様性と可変性に、考察全体の出発点があることを指し示した。同時に空間と時間との分けがたさにも言及し、今後の研究の方向性を示唆した
INNOVATIVE APPROACHES TO BIOMATERIALS’ TECHNOLOGY THROUGH SYSTEMATIC SPECTROSCOPIC ANALYSES
Get PDF京都工芸繊維大学博士（工学）The incidence of total hip arthroplasty (THA) has increased over the last decades, as a consequence of increasing of human average lifetime and changing in our habits and lifestyle. As people live longer, their bones become gradually brittler and the probability of incurring in traumatic events (such as dislocation or fracture) or developing arthritis increases. Furthermore, obesity has become a non-negligible problem in most of the First World countries. About 13% of the world adult population (about 650 million people) were obese in 2016, 11% of men and 15% of women. The only reasonable option to maintain mobility and to avoid chronic pain is often surgery. A major fraction of the people undergoing THA will surely outlive the expected service time of an artificial hip-joint (about 15-20 years for a successful surgery). Understanding degradation phenomena occurring inside the components of an artificial hipjoint can be of utmost importance to reduce costs related to revision surgeries and improve patient’s life. However, predictions do not always provide reliable outcomes because the intricate complexity of in-vivo phenomena are hard to reproduce and neither in-vitro tests nor finite elements simulations have been able, so far, to match reality. In the first part of this thesis, laser and electronic spectroscopy have been combined with several spectroscopic techniques (among which Raman micro-probe spectroscopy, X-ray photoelectron spectroscopy, Fourier-Transformed infrared spectroscopy etc.) to investigate degradation phenomena occurring on the ceramic femoral head and the polymeric acetabular cup; two of the most important components of an artificial hip joint. Zirconia Toughened Alumina (ZTA) retrieved femoral heads were investigated in-toto through a new automated protocol to obtain information about the the chemical, crystallographic, and micromechanical phenomena occurring in-vivo, pointing out a severe crystallographic instability. These information have been used, subsequently, to rationalize the discrepancy between predicted and in-vivo data. While current hydrothermal tests address only one of the possible triggers contributing to ZTA surface degradation, it has been found that transitional metal contamination accelerates the kinetics of such phenomena. Subsequently we focused on ceramics and polymer surface chemistry to understand sliding behavior of common bearings in artificial hip joints. In particular we focused on UHMWPE wear behavior against ZTA and compared it with a promising alternative non-oxide material, silicon nitride (Si3N4). Contrary to common knowledge, oxide-based ceramics are not completely bioinert. In fact, its tribologic behavior causes oxygen ions to be released from Al2O3 surfaces which, in turn, accelerate oxidative degradation in UHMWPE. On the other hand, silicon nitride scavenges oxygen from the tribolayer instead of releasin
Study of Photorefractive Dynamics in Poly(triarylamine)-based Polymer Composites
Get PDF京都工芸繊維大学博士（工学）The Photorefractive (PR) effect is defined as spatial modulation of the index of refraction due to charge redistribution in a nonlinear optical material. Holographic displays using the PR effect have received a great deal of attention because they can provide 3D images without special eyeglasses. For practical use of the PR materials, high external diffraction efficiency and fast response are indispensable. This thesis consists of six chapters. The PR dynamics in poly(triarylamine) (PTAA) based polymer composite was discussed from chapter 3 to chapter 5. In this study, PTAA was chosen as a PR photoconductive polymer, expected to lead fast response due to its high hole mobility.In chapter 3, the diffraction efficiency as a function of applied field demonstrated appropriate applied field region of 45-60 V μm-1. Wavelength dependency of the PR performance was examined. The shorter wavelength illumination induced higher diffraction efficiency and faster response time due to appropriate charge generation. In chapter 4, the PR dynamics of PTAA-based composite with small amount of a second electron acceptor was investigated. The second electron trap agents reduced photocurrent and suppressed the dielectric breakdown. The addition of bathophenanthroline (BPhen) provided high PR performance with response time of 397 μs, external diffraction efficiency of 5.9% and sensitivity of 1145 cm2 J-1. The effect of photoconductivity on the PR response time is discussed.In chapter 5, the composition ratio of PTAA-based composite was optimized to obtain the enhanced PR performance. The resulting composite achieved higher external diffraction efficiency of 23.9% and higher sensitivity of 1851 cm2 J-1. The key point of the optimization of the composite is the control of the absorption coefficient, related to the external diffraction efficiency. The extremely high sensitivity, as an indicator of the performance of real-time 3D holographic displays containing the elements of the response time and the external diffraction efficiency, indicated the PTAA-based PR composite as the most promising candidate of the holographic displays
アーク溶射におけるノズル噴流の影響
Get PDF京都工芸繊維大学博士（工学）材料の表面改質に関する重要なコーティング技術に溶射があり，この中でも産業界で多用されるアーク溶射を本研究の対象とした．アーク溶射とは2本の金属ワイヤに電圧をかけワイヤを溶融し，ノズルから噴出したアトマイジングガス（エア）で被溶射物表面へ吹き付ける溶射法である．エアの状態（噴流現象）がアーク溶射に与える影響に着目し，簡単に溶融粒子の微細化をコントロールする手法を確立することを研究目的とした．本研究を進めるにあたって，初めに実験的手法であるシュリーレン法を用いてノズル（実ノズル）から出る噴流現象の解明を試みた．シュリーレン法による可視化から，実ノズル（以下“ノーマルノズル”とする．）から出た噴流は膨張・圧縮を繰り返し減衰する複雑な3次元構造であることを明らかにした．しかしながら，シュリーレン法による可視化では流れが不鮮明で噴流構造の詳細把握には困難が生じたため，数値解析手法であるCFDによる補完を試みた．補完を試みるにあたり，計算手法の妥当性を確認するためワイヤの無い単純ノズルの解析を行った． CFDによるシミュレーションでシュリーレン観察の結果を良好に再現でき，計算手法の妥当性が確認された．次にワイヤがあるノーマルノズルの解析を行った結果，ワイヤ部で流れが圧縮されノズルから出た流れは膨張・圧縮を繰り返して減衰していることを明らかにした．また，ワイヤの見える向きによって噴流幅や減衰パターンが違うことから，噴流が3次元構造をしていることも明らかにした．実溶射では溶融したワイヤ（溶融粒子）がこの噴流に乗って被溶射物へ吹き付けられ，この過程で溶融粒子はより微細化すると考えられる．この噴流状態が溶融粒子の微細化に関係があると考えられるため，アーク点上流の2本のワイヤ間にプレートを設置したスプリッターノズルを考案した．プレート設置によってプレート部で波（膨張波など）が発生し，その波のエネルギによりアーク熱で溶融し引き千切られる際のワイヤサイズに変化が現れることを本ノズルでは期待した．CFDによりプレート部で膨張波が発生しノーマルノズルの噴流とは異なることを明らかにすると共に，設置位置の変更でも噴流状態に違いが現れることを明らかにした．最後に，ハイスピードカメラによる可視化手法を構築し，実溶射時の溶融粒子の飛翔を解明することを試みた．本可視化から，ノーマルノズルではアーク熱でワイヤが溶融し，エアで吹き付けられる過程で微細化することを明らかにした．一方，スプリッターノズルでは，ノーマルノズルに比べアーク熱で溶融したワイヤのサイズが小さいことを明らかにした．また，プレートの設置位置の違いで上記ワイヤのサイズに変化が現れることも明らかにした．これら得られた知見から，“プレート設置の有無”や“プレートの設置位置変更”で溶融するワイヤのサイズを制御し，皮膜品質の制御ができる可能性があることを示した
Cellulose-fueled Single-chamber Microbial Fuel Cells Using Cellulomonas fimi
Get PDF京都工芸繊維大学博士（工学）The purpose of this study is the development of a single-chamber microbial fuel cells (MFC) utilizing cellulose as fuel for Cellulomonas spp. with/without addition of electron mediator. Herein, the direct electron transfer of Cellulomonas fimi was studied and revealed. Celluloses of palm kernel shell was synthesized and utilized as fuel for studying electric generation for alternative renewable energy resources. In chapter 1, the principle of MFC using metabolism of microorganism to generate electron along with organic degradation. The thesis mentioned the advantage of MFC compared with thermal power generation of Carnot cycle having limitation, while MFC has not such limitation for converting chemical bond energy of organic substrate to electric energy. In chapter 2, Cellulomonas fimi, Cellulomonas biazotea, Cellulomonas flavigena were chosen to compare cellulose degradation and current generation. Cellulomonas fimi degraded cellulose with the highest quantity among the three microorganisms. The generated electric increased with cellulose degradation and the maximum electric power was 63% of the electric power generated by MFC with the well-known electric generating Shewanella oneidensis MR-1. Cellulomonas fimi was an excellent candidate to produce the electric current from cellulose via MFCs. In chapter 3, A single chamber microbial fuel cell utilizing cellulose as fuel for Cellulosemonas fimi without electron mediator provided electric generation. Cyclic voltammogram showed the oxidation peak caused by the electron transfer of cytochrome c and disappeared after adding antimycin A inhibiting electron transfer activity. This was thought that cytochrome c was on the membrane surface of the living cell and played a role in direct electron transfer. In chapter 4, Celluloses with different characterization were synthesized from palm kernel shell, and then used as fuel for Cellulomonas fimi in the MFCs to study and compare the MFC performances with commercially available cellulose. In chapter 5, general review and future perspective were described
歯面形状測定データを用いたインボリュート円筒歯車の新たな評価法
Get PDF京都工芸繊維大学博士（工学）本論文は3つの部分で構成されている。一つには、歯車測定機による歯面の測定とその表面性状の評価を行った。二つ目には超微細ピッチ歯車測定のための接触型プローブの開発と疑似粗さ評価への応用を検討し評価を行った。三つ目にはガウシアンフィルターによる歯すじ測定結果を適用したホブ切り歯車のピッチ誤差測定を安定化させる手法について提案し、その有効性について評価を行った
運動する水没物体を含む自由表面流れの数値解析に関する研究
Get PDF京都工芸繊維大学博士（工学）本論文では運動する水没物体を含む自由表面流れに着目し，このような流れ場に適用できる，非常に複雑な運動をする水没物体が領域に制限されずに，精度良く計算する手法を構築する．具体的には移動格子有限体積法および移動計算領域法と，自由表面を追跡する界面追跡法とを組み合わせた新しい数値解析手法を構築する．あわせて高さ関数法を移動領域に適用できるように拡張する．さらに移動格子有限体積法と高さ関数法とのカップリング法を構築する．自由表面を含む流体領域中に運動する物体がある流れ，言いかえると運動する水没物体に誘起される流れは，物体運動の速度や径路，自由表面と物体との距離によって，物体がうける抵抗・自由表面の形状が変わり，工学上の応用からきわめて興味深い流れ場であるといえる．例えば波力発電，海中に沈んでいる構造物等の検知や，潜水艇などの様々な適用先が考えられる．さらに水中においてより大きな運動をする物体に焦点をあてると，流れの中の魚の運動があげられる．魚は身近な存在であり，また魚ロボットへの応用が考えられ，生物が泳ぐ際の運動方向の変化方法や抵抗低減への応用が可能である．さらに，生物が外敵から逃げる際には，形状を大きく変形させることで，進行方向を変えることが知られている．この場合には直線運動のみに限らず，複雑な曲線運動をする場合も多い．このような曲線運動の場合には，物体にかかる抵抗・自由表面の形状が運動の速度や回転の半径によって変化することが予想される．したがって実用的にも物理的にも興味深い流れ場である．このような自由表面と運動する水没物体との流れにおいては，まず自由表面を精度よく表現する方法が重要であり，本論文では，計算効率が突出して高いことに注目し，界面追跡法の一つである高さ関数を用いる方法を採用した．さらに，初期に自由表面上に存在した格子は常に自由表面上にあるため，計算格子を集中させることで計算の解像度を担保しやすい．あわせて流体解析の計算スキームに対して時間とともに移動・変形する計算格子に適した方法が必要である．この方法に対しては流れ場に対する物理保存則を満足するだけでなく流れ場が計算格子の移動・変形に影響を受けない，つまり幾何保存則も満足する必要がある．幾何保存則を厳密に満足する移動格子に適した計算スキームとして，移動格子有限体積法が提案されている．この手法は有限体積法を時間-空間をあわせた検査体積に適用するものであり，様々な非定常流れ場に成功裏に適用してきた．さらに移動計算領域法を用い物体を含む計算領域全体を運動させることで，物体を自由に運動させつつ流れの解析を行うことが可能である．しかしながら，この手法は基本的に気体もしくは液体の単相流を想定した構築および適用がなされており，本論文で対象とするような自由表面流れへの適用はなされていない．このため，以下の検討を行った．まず界面追跡法として用いた高さ関数および離散化手法について検討した．特に物体が運動する場合への展開を考慮し，高さ関数法を計算領域が移動する場合に適用可能なように離散化手法を構築した．次に，用いた計算コードの基礎的検証として，まず水没物体のない自由表面流れへ適用した．具体的には，直方体容器内のスロッシング流れに適用し，他者の実験値および解析結果と比較した．さらに，円筒容器内のスロッシング流れへ適用し，他者の解析結果と比較した．また流れ場の常流・射流がフルード数の変更により変化するかを確認するために傾斜付流路に適用し，解析解や他者の数値解との比較を行った．以上の基礎的検証から水没物体のない流れ場に対して本手法の有効性を示した．次に単純な運動をする水没物体を含む自由表面流れへの適用を行った．最初に単純な二次元形状である水没円柱を対象とし，円柱を固定した場合および円柱が直線運動する場合へ適用し，他者の数値解との比較を行った．また三次元形状への適用可能性を示すため，水没球への適用を行った．以上の結果から単純な運動をする水没物体のある流れ場に対して本手法の有効性を示した．最後に応用として運動する魚への適用を行った．まず初めに検証として単一の魚が旋回運動する場合に適用し，旋回の半径および初期自由表面からの魚の深さを変更した解析を行い回転半径および深さの影響を考察した．次に複数の魚として二匹の魚が存在する場合の旋回運動を解析した．魚の配置は前後に並ぶ場合と横に並ぶ場合で実施し，流れ場への影響を考察した．この応用から本手法が旋回運動する水没物体を含む自由表面流れに有効であることを示した．以上より本研究で提案した手法は，複雑な運動を行う水没物体を含む自由表面流れの数値解析に対して有効な手法であると結論された
