New Invariants for Partitioning a Graph into 2-connected Subgraphs

A vertex partition in which every part induces a 2-connected subgraph is called a 2-proper partition. This concept was introduced by Ferrara et al. in 2013, and Borozan et al. gave the best possible minimum degree condition for the existence of a 2-proper partition in 2016. Later, in 2022, Chen et al. extended the result by showing a minimum degree sum condition for the existence of 2-proper partition. In this paper, we introduce two new invariants of graph, denoted by $\sigma^*(G)$ and $\alpha^*(G)$. These two invariants are defined from degree sum on all independent sets with some property. We prove that if a graph $G$ satisfies $\sigma^*(G)\geq |V(G)|$, then with some exceptions, $G$ has a 2-proper partition with at most $\alpha^*(G)$ parts. This result is best possible, and implies both of the results by Borozan et al. and by Chen et al.. Moreover, as a corollary of our result, we give a minimum degree product condition for the existence of a 2-proper partition.Comment: 14 pages, 4 figure

Detection of sequential activation of left atrium and coronary sinus musculature in the general population

学位記番号：医博甲160

Localised surface plasmon resonance inducing cooperative Jahn–Teller effect for crystal phase-change in a nanocrystal

結晶中の電子の集団的な運動が原子を動かすプラズモン誘起原子変位を初めて発見 --見えない光学センサーなど新技術の実現に期待--. 京都大学プレスリリース. 2023-08-01.The Jahn–Teller effect, a phase transition phenomenon involving the spontaneous breakdown of symmetry in molecules and crystals, causes important physical and chemical changes that affect various fields of science. In this study, we discovered that localised surface plasmon resonance (LSPR) induced the cooperative Jahn–Teller effect in covellite CuS nanocrystals (NCs), causing metastable displacive ion movements. Electron diffraction measurements under photo illumination, ultrafast time-resolved electron diffraction analyses, and theoretical calculations of semiconductive plasmonic CuS NCs showed that metastable displacive ion movements due to the LSPR-induced cooperative Jahn–Teller effect delayed the relaxation of LSPR in the microsecond region. Furthermore, the displacive ion movements caused photo-switching of the conductivity in CuS NC films at room temperature (22 °C), such as in transparent variable resistance infrared sensors. This study pushes the limits of plasmonics from tentative control of collective oscillation to metastable crystal structure manipulation

Characteristics of systolic and diastolic potentials recorded in the left interventricular septum in verapamil-sensitive left ventricular tachycardia

We studied the electrophysiological characteristics of systolic (SP) and diastolic (DP) potentials recorded during sinus rhythm (SR) in the left interventricular septum of a 27 year-old woman presenting with verapamil-sensitive idiopathic left ventricular tachycardia (VT). During SR, and during VT, SP was activated from ventricular base-to-apex, and DP from apex-to-base. SP and DP were both detected at the site of successful ablation during SR, whereas during VT, DP was detected away from the earliest activation site. Thus, SP apparently reflected a critical component of the reentrant circuit, while DP reflected the activation of a bystander pathway

Prediction of postoperative liver failure and evaluation of modifi ed criteria for liver resection with computed volume analysis

Background/Aims: The exact resectable volume corresponding to liver function has never been elucidated for safe resection of a diseased liver. The aim of this study was to evaluate whether modifi ed criteria for safe liver resection could be used to predict postoperative liver failure/dysfunction.Methodology: Consecutive 86 patients who underwent liver resections were assessed. Clinical laboratory tests and liver volume were evaluated. The modifi ed criteria used to determine safe liver resection consisted of indocyanine green retention rate at 15 min (ICGR15), antithrombin III (ATIII), clearance index (HH15), and receptor index (LHL15). We compared clinical outcomes after liver resection using our modifi ed criteria and Makuuchi criteria. Results: There were 78 patients without liver failure and 8 with liver failure/dysfunction. ICGR15 (P < 0.001), ATIII (P = 0.036), operative time (P = 0.014), tumor type (P = 0.047), modifi ed criteria score (P = 0.037), lost liver volume (P = 0.006), and modifi ed criteria (P= 0.007) were signifi cantly different between the groups. Diagnostic probability of modifi ed criteria (P = 0.007) was better than the one of Makuuchi criteria (P = 0.271).Conclusions: Postoperative liver failure/dysfunction could be predicted using the modifi ed criteria. Furthermore, the criteria could be used to provide a putative liver volume for safe removal.departmental bulletin pape

Development of catheter-type tactile sensor composed of polyvinylidene fluoride (PVDF) film

To achieve quantitative palpation in vivo, we developed a catheter-type tactile sensor composed of a polyvinylidene fluoride film for minimally invasive surgery. We evaluated the fundamental performance of the prototype sensor by a weight-drop test. We also measured the output of the prototype sensor as it was inserted into a blood vessel model with shapes mimicking lesions. The ø2-mm sensor passed easily into the blood vessel model with lesion-like shapes. Sensor outputs corresponded to the shape of the inner wall of the blood vessel model, making it possible to determine the position of a protrusion and the convexity interval of a rough surface by filtering and frequency analysis of the output

Irregular atrial flutter following pulmonary vein isolation for persistent atrial fibrillation

AbstractA 65-year-old man with a history of refractory paroxysmal atrial fibrillation (AF) underwent catheter ablation for persistent AF lasting 2 months. AF was not terminated after complete isolation of the 4 pulmonary veins (PV). Instead, it was transformed to a sustained atrial tachyarrhythmia with beat-to-beat variability in the atrial cycle length. A 12-lead electrocardiogram during tachycardia showed negative flutter-like waves in the inferior leads. Entrainment pacing along the tricuspid annulus confirmed the diagnosis of irregular cavotricuspid isthmus (CTI)-dependent typical atrial flutter (AFL). Linear ablation of the CTI terminated AFL and restored sinus rhythm