一様スパニングツリーとループ除去ランダムウォークの上のランダムウォーク

京都大学新制・課程博士博士(情報学)甲第25436号情博第874号京都大学大学院情報学研究科先端数理科学専攻(主査)准教授 白石 大典, 教授 磯 祐介, 教授 木上 淳学位規則第4条第1項該当Doctor of InformaticsKyoto UniversityDFA

Volume and heat kernel fluctuations for the three-dimensional uniform spanning tree

Let $\mathcal{U}$ be the uniform spanning tree on $\mathbb{Z}^{3}$. We show the occurrence of log-logarithmic fluctuations around the leading order for the volume of intrinsic balls in $\mathcal{U}$. As an application, we obtain similar fluctuations for the quenched heat kernel of the simple random walk on $\mathcal{U}$.Comment: 39 pages, 20 figure

Annealed transition density of simple random walk on a high-dimensional loop-erased random walk

We derive sub-Gaussian bounds for the annealed transition density of the simple random walk on a high-dimensional loop-erased random walk. The walk dimension that appears in these is the exponent governing the space-time scaling of the process with respect to the extrinsic Euclidean distance, which contrasts with the exponent given by the intrinsic graph distance that appears in the corresponding quenched bounds. We prove our main result using novel pointwise Gaussian estimates on the distribution of the high-dimensional loop-erased random walk.Comment: 36 pages, 7 figure

A water-soluble extract from cultured medium of Ganoderma lucidum (Reishi) mycelia attenuates the small intestinal injury induced by anti-cancer drugs

The present study investigated whether a water-soluble extract from the culture medium of Ganoderma lucidum (Reishi) mycelia (MAK) is able to protect the small intestine against damage induced by anti-cancer drugs. Six-week-old male B6C3F1/Crlj mice were fed a basal diet (MF) alone or with various doses of MAK or Agarics blazei Murrill (AGA) beginning one week before treatment with the anti-cancer drugs. Mice were sacrificed 3.5 days after injection of the anti-cancer drug, the small intestine was removed and tissue specimens were examined for the regeneration of small intestinal crypts. In experiment 1, the number of regenerative crypts after the administration of 5-fluorouracil (5FU) intravenously (250 mg/kg) or intraperitoneally (250 or 500 mg/kg) was compared after treatment with MAK or AGA. MAK protected against 5FU-induced small intestinal injury whereas AGA did not. In experiment 2, we investigated the protective effect of MAK against small intestinal injury induced by the anti-cancer drugs: UFT (tegafur with uracil; 1,000 mg/kg, orally), cisplatin (CDDP; 12.5 and 25 mg/kg, intraperitoneally), cyclophosphamide (CPA; 250 mg/kg, orally) and gefitinib (Iressa; 2,000 and 4,000 mg/kg, orally). UFT and CDDP decreased the number of regenerative crypts, but treatment with MAK attenuated the extent of UFT- or CDDP-induced small intestinal injury. CPA or Iressa plus MAK up-regulated crypt regeneration. The present results indicate that MAK ameliorates the small intestinal injury caused by several anti-cancer drugs, suggesting that MAK is a potential preventive agent against this common adverse effect of chemotherapy

Comparison of cortical activation during subtraction in mental calculation and with a calculator

Several studies have shown that various types of cognitive processing exist and exert different effects on brain activity. However, when a subject performs the same task, whether the task involves processing or not, such as in mental calculation or with a calculator, the different influences on the brain remain unclear. The purpose of this study was to examine whether the influence of cortical activation when performing mental calculation and using a calculator have different effects on the brain. Fifteen healthy, right-handed participants (mean age, 26.3 ± 8.5 years; 12 men, 27.7 ± 9.0 years; 3 women, 20.6 ± 1.1 years) were recruited as subjects. We measured oxygenated hemoglobin (oxy-Hb) levels while subjects performed subtraction tasks by mental calculation or using a calculator (3 min each). Measurements were made at the frontal lobe and temporal lobe. In both lobes, oxy-Hb level was significantly increased during mental calculation. Locations showing significantly increased oxy-Hb in mental calculation were the prefrontal cortex in the frontal lobe and supramarginal gyrus in the temporal lobe. These results suggest that the brain responds differently to tasks in mental calculation and using a calculator. We hypothesized that using the electronic calculator needs fewer neural networks than performing mental calculation. In recent years, thanks to the development of machines, many tasks have been automated, making our lives easier and more convenient. Our results may provide one example that the developments of modern technology influence brain function.ArticleBiochemistry & Analytical Biochemistry.4(3):185(2015)journal articl

低インスリン血症は、非糖尿病急性非代償性心不全患者において、全死亡、心血管死の独立した予後予測因子である

Background Insulin beneficially affects myocardial functions during myocardial ischemia. It increases glucose-derived ATP production, decreases oxygen consumption, suppresses apoptosis of cardiomyocytes, and promotes the survival of cardiomyocytes. Patients with chronic heart failure generally have high insulin resistance, which is correlated with poor outcomes. The role of insulin in acute decompensated heart failure (ADHF) remains unclear. This study aimed to investigate the prognostic value of serum insulin level at the time of admission for long-term outcomes in patients with ADHF. Methods and Results We enrolled 1074 consecutive patients who were admitted to our department for ADHF. Of these 1074 patients, we studied the impact of insulin on the prognosis of ADHF in 241 patients without diabetes mellitus. The patients were divided into groups according to low, intermediate, and high tertiles of serum insulin levels. Primary end points were all-cause death and cardiovascular death. During a mean follow-up of 21.8 months, 71 all-cause deaths and 38 cardiovascular deaths occurred. Kaplan-Meier analysis showed that all-cause and cardiovascular mortality was significantly higher in the low-insulin group than those in the intermediate- and high-insulin groups (log-rank P=0.0046 and P=0.038, respectively). Moreover, according to the multivariable analysis, low serum insulin was an independent predictor of all-cause and cardiovascular mortality (hazard ratio, 2.37 [95% CI, 1.24-4.65; P=0.009] and 2.94 [95% CI, 1.12-8.19; P=0.028], respectively). Conclusions Low serum insulin levels were associated with increased risk of all-cause and cardiovascular death in ADHF patients without diabetes mellitus.博士（医学）・甲第808号・令和4年3月15日© 2020 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License(https://creativecommons.org/licenses/by-nc/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes

日本における非代償性急性心不全患者の30日および90日以内の心不全再入院の発生率と臨床的意義 : NARA-HF研究より

Background: Countermeasure development for early rehospitalization for heart failure (re-HHF) is an urgent and important issue in Western countries and Japan.Methods and Results:Of 1,074 consecutive NARA-HF study participants with acute decompensated HF admitted to hospital as an emergency between January 2007 and December 2016, we excluded 291 without follow-up data, who died in hospital, or who had previous HF-related hospitalizations, leaving 783 in the analysis. During the median follow-up period of 895 days, 241 patients were re-admitted for HF. The incidence of re-HHF was the highest within the first 30 days of discharge (3.3% [26 patients]) and remained high until 90 days, after which it decreased sharply. Within 90 days of discharge, 63 (8.0%) patients were re-admitted. Kaplan-Meier analysis revealed that patients with 90-day re-HHF had worse prognoses than those without 90-day re-HHF in terms of all-cause death (hazard ratio [HR] 2.321, 95% confidence interval [CI] 1.654-3.174; P<0.001) and cardiovascular death (HR 3.396, 95% CI 2.153-5.145; P<0.001). Multivariate analysis indicated that only male sex was an independent predictor of 90-day re-HHF. Conclusions: The incidence of early re-HHF was lower in Japan than in Western countries. Its predictors are not related to the clinical factors of HF, indicating that a new comprehensive approach might be needed to prevent early re-HHF.博士（医学）・甲第735号・令和2年3月16日日本循環器学会の許諾を得て登録（2020年9月2日付）ジャーナル公式サイト（日本循環器学会HP内）：https://www.j-circ.or.jp/journal/公開サイト（J-STAGE）：https://www.jstage.jst.go.jp/browse/circj