京都大学 / 新制・課程博士 / 博士(理学) / 甲第23038号 / 理博第4715号 / 新制||理||1676(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 若宮 淳志, 教授 時任 宣博 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20396号 / 工博第4333号 / 新制||工||1671(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 村田 靖次郎, 教授 辻 康之, 教授 中村 正治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p> Investigations on the stability and reactions of various isomers of the benzohomotropylium/bridged [11]-annulene system are presented in this thesis. As 1,6-methano-[11]-annulenium cations are isomeric with benzohomotropylium cations in principle it is possible for these systems to be interconverted by a circumambulatory migration of the 'bridging' methano group. If this reaction were to proceed to equilibrium it would allow the examination of the thermodynamic stability of the various isomers.</p> <p> Homotropylium cations with two methyl groups at C8 are known to undergo facile circumambulatory rearrangements. Thus in this work the 1-hydroxy 8,8-dimethyl-2,3-benzohomotropylium and 1-hydroxy 8,8-dimethyl-4,5-benzohomotropylium cations have been prepared by protonation of the corresponding 2,3- and 4,5- benzohomotropones in FSO3H. On the basis of their 1H NMR spectra it is concluded that they can properly be regarded as homoaromatic cations. The thermal isomerizations of these cations have been studied in detail. The thermal isomerization of these cations led to the formation of a series of products but does not yield the corresponding [11]-annulenium isomer. In addition the barriers to ring inversion in these cations were found to be much lower than those of other homotropylium cations. This suggests that the former cations have a very open structure. Besides this experimental approach, the relative stability of these isomers has been explored using MNDO calculations. The calculated heats of formation (ΔHf) showed that the 1-benzohomotropylium cation is more stable than the corresponding [11]-annulenium ion by 21 kcal/mol.</p> / Thesis / Master of Science (MSc)

3D genome organization recapitulates genome function, typically at the level of transcriptional state or chromatin state. Ciliates like Oxytricha trifallax possess highly specialized germline genomes, which play a role in sexual development but are largely transcriptionally silent. During Oxytricha development, the germline undergoes genome-wide rearrangement, transforming into a structurally distinct, transcriptionally active somatic genome. This wholesale rearrangement is programmed by transgenerational RNA copies of the somatic genome, which guide the retention of a small portion of the germline. Retained and eliminated sequences must be distinguished from each other and processed separately, but how this dichotomy is effected spatially or by chromatin organization is unknown. The breadth of Oxytricha genome dynamics presents the possibility of a complex relationship between chromatin architecture and genome function. We present new tools for studying the Oxytricha germline and apply them to map the 3D organization of the genome’s vegetative and developmental states using Hi-C. We find that the vegetative conformation primes the germline for development, while a massive spatial reorganization of the genome during development differentiates between retained and eliminated regions and precedes rearrangement of DNA. Further experiments suggest a role for RNA-DNA interactions and chromatin remodeling in this reorganization. This evidence supports a critical role for 3D architecture in programmed genome rearrangement.

As WDM results in an ever-increasing trend of traffic concentration, any failure on a single fiber-link or a single switching node will be catastrophic. Rapid restoration can recover the affected traffic so as to make the network more robust and reliable. The conventional restoration methods are designed mostly for reconfiguring the network topology; they are not immune from service interruption. In this thesis, an effective algorithm called backup-path-wavelength rearrangement scheme is proposed to reduce the connection blocking probability in an all-optical network. The proposed scheme performs wavelength retuning on the backup paths to improve the acceptance probability for new connection requests and introduce zero service interruption to the traffic in the network. The performance evaluation indicates that the connection blocking probability can be decreased greatly by the proposed scheme. The combination of BPWR and traffic grooming can efficiently alleviate the wavelength continuity constraint.

No description available.

No description available.

No description available.

No description available.

No description available.