将来の輻輳状態の予測に基づくアクティブキュー管理手法の提案

電気通信大学200

Effect of Sn Atom on Poly(Ｌ-lactic acid) Pyrolysis

Tin 2-ethylhexanoate is an indispensable component of commercially available poly(L-lactic acid) (PLLA). However, the thermal degradation kinetics of PLLA containing Sn have not yet clearly been established; in particular, whether the degradation mechanism is a 1st-order or a random reaction. To clarify the effects of residual Sn on PLLA pyrolysis, PLLA samples with different Sn contents from 20 to 607 ppm were prepared and subjected to pyrolysis analysed with pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS) and thermogravimetry (TG). The pyrolysis of PLLA Sn-607 (Sn content: 607 ppm) with Py-GC/MS in the temperature range of 40–400 °C selectively produced lactides. In contrast, the pyrolysis of PLLA Sn-20 (Sn content: 20 ppm) was accompanied by the production of cyclic oligomers. The dynamic pyrolysis of PLLA-Sn samples by TG clearly indicated that with an increase in Sn content there was a shift to a lower degradation temperature range and a decrease in activation energy Ea. The kinetic analysis of the dynamic pyrolysis data indicates that the Sn-catalyzed pyrolysis starts through a random degradation behaviour and then shifts to a zero-order weight loss as the main process. Three reactions were put forward as being possible mechanisms of the zero-order weight loss; one being an unzipping reaction accompanying a random transesterification, the other two being the Sn-catalyzed pseudo-selective and selective lactide elimination reactions from random positions on a polymer chain. The kinetic parameter values obtained could be adequately explained for each degradation process

Effect of Spin-Orbit Interaction in Spin-Triplet Superconductor: Structure of d{\bf d}-vector and Anomalous 17^{17}O-NQR Relaxation in Sr2_2RuO4_4

Supposing the spin-triplet superconducting state of Sr$_2$RuO$_4$, the spin-orbit (SO) coupling associated with relative motion in Cooper pairs is calculated by extending the method for the dipole-dipole coupling given by Leggett in the superfluid $^{3}$He. It is shown that the SO coupling works only in the equal-spin pairing (ESP) state to make the pair angular momentum $\hbar{\vec L}$ and the pair spin angular momentum ${\rm i}{\vec d}\times{\vec d}^{*}$ parallel with each other. The SO coupling gives rise to the internal Josephson effect in a chiral ESP state as in superfluid A-phase of $^3$He with a help of an additional anisotropy arising from SO coupling of atomic origin which works to direct the {\bf d}-vector into $ab$-plane. This resolves the problem of the anomalous relaxation of $^{17}$O-NQR and the structure of {\bf d}-vector in Sr$_2$RuO$_4$.Comment: Accepted for publication in J. Phys. Soc. Jpn. vol.79 (2010), No.2 (February issue); 18 pages, 2 figure

イマージョン キョウイク トシテノ スイケン カンキョウ キョウイク : エイゴジュク ニ カヨウ ジドウ ニ タイスル シュノーケル ヤガイ カツドウ ノ キョウイク セイカ

シュノーケリングによる野外体験活動と英語教育を融合したイマージョン教育としての水圏環境教育の可能性について検証した。本研究結果から，水圏環境意識の低い，あるいは持っていない学習者に興味・関心を促すということが明らかとなった。昨今，グローバルコミュニケーション能力が求められている中，イマージョン教育としての水圏環境教育は，単に語学力の習得にとどまらず，自然環境の観察や探究活動を通し，思考力，判断力，行動力を育成し，地球規模の環境問題の解決に向けて活躍できる国際人としての素養を高めることにつながると考えられる。今後は他教科やスポーツ，スイミングクラブなどの他の分野と融合をさせて多種多様なプログラム作成により国際理解教育，総合的な学習の時間等において活用されることを期待したい。This study explored the use of aquatic marine environmental education as immersion education merging snorkeling activity and english education. Results clarified that children who did not have consciousness or who were less aware of aquatic marine environments came to have interest and concern about it. Aquatic marine environmental education as immersion education can enhance not only linguistic talent, but also aquatic marine environmental literacy including dognitive ability, judgment, and action through environmental investigation and exploration to resolve the global environmental issues. Aquatic marine environmental education is anticipated for use as immersion education for other subjects such as sports, international education study, integrated study, and other facilities such as swimming clubs.星原貴保: ダイビングショップ　ナチュラルブル

Pyrolysis Kinetics of Poly(L-lactide) with Carboxyl and Calcium Salt End Structures

To clarify the pyrolysis mechanism of poly(L-lactide), which has been reported as complex, the thermal decomposition of carboxyl type and calcium ion end capped PLLA (PLLA-H and PLLA-Ca, respectively) was investigated by means of thermogravimetric analysis (TG), and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The TG data revealed that PLLA-Ca has a lower pyrolysis temperature (220~360°C) than that of carboxyl type PLLA-H (280~370°C). The apparent activation energy of the decomposition reaction was estimated from TG curves at different heating rates by plural methods to be 176 and 98 kJ mol-1 for PLLA-H and PLLA-Ca, respectively. Further kinetic studies indicated that PLLA-H degraded mainly through a random reaction with a pre-exponential factor A=2.0×1012 s-1, whereas PLLA-Ca degraded by way of a 1st-order reaction with A=8.4×105 s-1. Pyrolysis products of PLLA-H were composed of lactides and other cyclic oligomers, while the degradation products of PLLA-Ca were principally lactides. The main reaction pathway for PLLA-H pyrolysis was regarded as the random transesterification, whereas for PLLA-Ca pyrolysis the unzipping depolymerization process was dominant

Alcohol consumption is associated with an increased risk of erosive esophagitis and Barrett's epithelium in Japanese men

<p>Abstract</p> <p>Background</p> <p>Evidence regarding the association between alcohol consumption and the gastro-esophageal reflux disease (GERD) spectrum has been conflicting. We examined the association between alcohol consumption and erosive esophagitis and Barrett's epithelium in Japanese men.</p> <p>Methods</p> <p>The study population comprised 463 men subjects who had undergone an upper endoscopy at the Gastroenterology Division of Yokohama City University Hospital between August 2005 and July 2006. The presence of erosive esophagitis and Barrett's epithelium was diagnosed based on the Los Angeles Classification and the Prague C and M Criteria, respectively. We divided the study population into four groups: never drinkers, light drinkers (less than 25.0 g of ethanol per day), moderate drinkers (25.0 to 50.0 g of ethanol per day), and heavy drinkers (more than 50.0 g of ethanol per day). A linear regression of the logistic regression analysis was used to analyze the dose-response trends.</p> <p>Results</p> <p>Compared with never drinkers, light drinkers (less than 25.0 g ethanol per day), moderate drinkers (25.0 to 50.0 g per day), and heavy drinkers (more than 50.0 g per day) had ORs for erosive esophagitis of 1.110 (95% CI: 0.553 – 2.228, p = 0.7688), 1.880 (95% CI: 1.015 – 3.484, p = 0.0445) and 1.988 (95% CI: 1.120 – 3.534, p = 0.0190), respectively. These groups had ORs for Barrett's epithelium of 1.278 (95% CI: 0.752 – 2.170, p = 0.3643), 1.458 (95% CI: 0.873 – 2.433, p = 0.1500), and 1.912 (95% CI: 1.185 – 3.086, p = 0.0079), respectively. The odds ratios/grams (alcohol)/day of dose response trends for erosive esophagitis and Barrett's epithelium were 1.015 (95% CI: 1.004–1.026, p = 0.0066) and 1.012 (95% CI: 1.003–1.021, p = 0.0079), respectively.</p> <p>Conclusion</p> <p>These findings suggest that alcohol consumption in Japanese men tends to be associated with an increased risk of erosive esophagitis and Barrett's epithelium.</p

Clinical Significance of Hiatal Hernia

The relationship between hiatal hernias and gastroesophageal reflux disease (GERD) has been greatly debated over the past decades, with the importance of hiatal hernias first being overemphasized and then later being nearly neglected. It is now understood that both the anatomical (hiatal hernia) and the physiological (lower esophageal sphincter) features of the gastroesophageal junction play important, but independent, roles in the pathogenesis of GERD, constituting the widely accepted "two-sphincter hypothesis." The gastroesophageal junction is an anatomically complex area with an inherent antireflux barrier function. However, the gastroesophageal junction becomes incompetent and esophageal acid clearance is compromised in patients with hiatal hernia, which facilitates the development of GERD. Of the different types of hiatal hernias (types I, II, III, and IV), type I (sliding) hiatal hernias are closely associated with GERD. Because GERD may lead to reflux esophagitis, Barrett's esophagus and esophageal adenocarcinoma, a better understanding of this association is warranted. Hiatal hernias can be diagnosed radiographically, endoscopically or manometrically, with each modality having its own limitations, especially in the diagnosis of hiatal hernias less than 2 cm in length. In the future, high resolution manometry should be a promising method for accurately assessing the association between hiatal hernias and GERD. The treatment of a hiatal hernia is similar to the management of GERD and should be reserved for those with symptoms attributable to this condition. Surgery should be considered for those patients with refractory symptoms and for those who develop complications, such as recurrent bleeding, ulcerations or strictures