紅色進化系統藻類における光捕集タンパク質複合体の分子進化と機能

京都大学新制・課程博士博士(農学)甲第26047号農博第2657号京都大学大学院農学研究科応用生命科学専攻(主査)教授 伊福 健太郎, 教授 菅瀬 謙治, 教授 白井 理学位規則第4条第1項該当Doctor of Agricultural ScienceKyoto UniversityDGA

<技術報告>桜島火山観測所での無人機活用について

本文ファイル差し替え(2025-08-27

Semantic-Retention Attack for Continual Named Entity Recognition

Continual Named Entity Recognition (CNER) aims to learn new entity types while preventing the catastrophic forgetting of previously learned types, expanding the flexibility of NER. However, the robustness of CNER models, which are typically evaluated through adversarial attacks, hasn’t been fully investigated due to two crucial challenges. Firstly, most works only focus on attacking NER models, in which the model is designed for a fixed dataset without considering the dynamic nature of real-world scenarios. These methods are not tailored to the challenges of the continual learning setting. Secondly, current textual attacks discretely change target words, which are widely used in sentence-level or document-level tasks. But in the word-level CNER task, even changes in one character may lead to a shift in the true label, making it difficult to reliably evaluate the results of the attack. Additionally, this type of attack is easily observed and lacks stealthiness. Thus, we propose a novel attack approach named Semantic-Retention Attack (SRA). To fit the continual learning tasks, SRA disrupts CNER models by enhancing catastrophic forgetting and knowledge confusion. To improve the reliability and stealthiness of the proposed attack, we perform a continuous transformation on the discrete texts and then apply a trainable SRA on them, ensuring the retention of the original semantics of the texts and avoiding changes in word-level ground truth labels. Experiments across ten CNER settings show our approach decreases performance to at most 51.63%, reaching the best degradation independent of the initial performance of CNER models while maintaining the best stealthiness, which exposes security vulnerabilities

新奇な非平衡状態におけるスピン輸送現象の理論研究

付記する学位プログラム名: 京都大学卓越大学院プログラム「先端光・電子デバイス創成学」京都大学新制・課程博士博士(理学)甲第25790号理博第5101号京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)教授 柳瀬 陽一, 教授 齊藤 圭司, 准教授 PETERS Robert学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDFA

Model-based analysis of the circadian rhythm generation of bioluminescence reporter activity in duckweed

Bioluminescence monitoring techniques are widely used to study the gene expression dynamics in living plants. Monitoring the bioluminescence from a luciferase gene under the control of a circadian promoter is indispensable for examining plant circadian systems. The bioluminescence monitoring technique was successfully applied to physiological studies of circadian rhythms in duckweed plants. It has been reported that a luciferase gene under a constitutive promoter also exhibits a bioluminescent circadian rhythm in duckweed. However, the mechanisms underlying rhythm generation remain unknown. In this study, we performed a model-based analysis to evaluate the machinery that generates the bioluminescence rhythm. We hypothesized the rhythmic factor of three aspects regarding the bioluminescence intensities of luciferase in cells: luminescence efficiency, production rate, and degradation rate. Theoretically, if the latter two are involved in rhythm generation, the difference in luciferase stability affects the amplitude and phase relations of the bioluminescence rhythm. Luciferase stability is irrelevant to these rhythm properties if only the luminescence efficiency is involved. First, we simulated the bioluminescence rhythms of two luciferases with different stabilities associated with each of three rhythmic factors. Luciferase stability was set based on the reported values for Emerald-luciferase and Emerald-luciferase-PEST. We then experimentally examined the bioluminescence rhythms of reporters of these luciferases driven by the CAULIFLOWER MOSAIC VIRUS 35S promoter in the duckweed Lemna japonica. Their circadian properties matched those obtained from the simulation of the luminescence efficiency. This supports the view that cells in duckweed show circadian changes in physiological conditions associated with the luciferase enzyme reaction

Characteristic dislocation slip behavior in polycrystalline HfNbTiZr refractory medium entropy alloy

The present work reports characteristics of dislocation slip behavior in an equi-atomic HfNbTiZr refractory medium entropy alloy (RMEA) and its systematic comparison with pure niobium (Nb). Fully-recrystallized specimens were fabricated by cold rolling and subsequent annealing, and uniaxial tensile deformation was applied at room temperature. Slip trace morphologies on the surfaces of the tensile-deformed materials were quantitatively characterized, and the so-called ψ and χ relationships of the observed slip traces were evaluated by a newly developed method for polycrystalline specimens. Wavy slip traces were observed in most grains in the pure Nb. They consisted of low-indexed slip planes, such as {1 1 0}, and {1 1 2}, and high-indexed (or undetermined) slip planes. Some straight slip traces persisting on the low-indexed slip planes were also found in the pure Nb. In contrast, straight slip traces were dominant in the RMEA. The straight slip traces in the RMEA were not parallel to particular slip planes but mostly distributed along the maximum shear stress plane (MSSP), indicating that frequent cross slip in very short intervals occurred. Large deviations of slip planes from the MSSP in a few grains of the RMEA were attributed to the slip transfer from neighboring grains as a characteristic of polycrystalline materials. Frequent cross slip in short intervals, attributed to homogeneous slip resistance distribution for screw dislocations in the RMEA originating from the chemical heterogeneity on an atomic scale, was proposed as a novel mechanism responsible for the unique slip behavior and macroscopic deformation behavior

Allogenic transplantation therapy of iPS cell-derived dopamine progenitors for Parkinson's disease -Current status of the Kyoto Trial and future perspectives-

Transplantation therapy using induced pluripotent stem cell (iPS) cell-derived dopamine (DA) progenitors for Parkinson's disease (PD) has attracted attention as an innovative treatment to restore DA neurons in PD, which leads to the improvement of motor disturbance. iPS cells are multipotent stem cells with very high proliferation activity, created by reprogramming mature somatic cells through the transduction of four transcription factors. Relative to fetal midbrain DA neurons, iPS cells have advantages in terms of ethical aspects and availability. On the other hand, the most serious concern associated with therapies with ES/iPS cells is the risk of tumor growth that is caused by the proliferation of undifferentiated ES/iPS cells. Human ES cells that differentiate into DA neurons have been shown to form teratomas. Another concern is graft-induced dyskinesia (GID). GID, which is likely caused by several factors including contamination with serotonergic neurons, developed in the recipients of fetal ventral midbrain (VM) in randomized controlled trials. To enrich the DA progenitor cells and eliminate unwanted cells, a protocol for sorting midbrain DA neurons with antibodies against CORIN, a marker for floor plates, was developed. CORIN-sorted dopamine progenitors were transplanted into the bilateral putamina of MPTP-treated Parkinson models of cynomolgus monkeys, resulting in 18F-DOPA PET-positive graft formation and motor improvement without tumor formation two years after the surgeries. Very recently, a phase I/II trial of iPSC-derived, CORIN-sorted dopaminergic cells for Parkinson's disease was completed (The Kyoto Trial) (Takahashi, 2020; Sawamoto et al., 2025) [1,2]. Based on the results of the trial, we would like to discuss the current status and future perspectives of iPS cell therapy for PD

Cuneanes as Potential Benzene Bioisosteres Having Chirality

Cuneane, a structural isomer of cubane, possesses C[2v] symmetry, unlike the Oₕ symmetry of cubane. It can exhibit chirality with only a single substituent, differentiating it from cubane. Consequently, cuneane is being explored as a potential benzene bioisostere in pharmaceutical molecules, adding complexity such as chirality through isomerization of the cubane skeleton. Although there has been limited research on the synthesis of cuneane, recent years have seen increased attention devoted to this cage hydrocarbon. In this short review, we will discuss recent advances in the synthesis, utilization, and transformations of the cuneane framework into other cage hydrocarbons

Diracラインノード物質CaSb₂およびCaAg₁₋ₓPdₓPにおける非自明な転移の発見とその超伝導との関係

付記する学位プログラム名: 京都大学卓越大学院プログラム「先端光・電子デバイス創成学」京都大学新制・課程博士博士(理学)甲第25793号理博第5104号京都大学大学院理学研究科物理学・宇宙物理学専攻(主査)教授 石田 憲二, 教授 幸坂 祐生, 准教授 北川 俊作学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA