Superconductivity in a Two-Orbital Hubbard Model with Electron and Hole Fermi Pockets: Application in Iron Oxypnictide Superconductors

We investigate the electronic states of a one-dimensional two-orbital Hubbard model with band splitting by the exact diagonalization method. The Luttinger liquid parameter $K_{\rho}$ is calculated to obtain superconducting (SC) phase diagram as a function of on-site interactions: the intra- and inter-orbital Coulomb $U$ and $U'$, the Hund coupling $J$, and the pair transfer $J'$. In this model, electron and hole Fermi pockets are produced when the Fermi level crosses both the upper and lower orbital bands. We find that the system shows two types of SC phases, the SC \Roman{u'-large} for $U>U'$ and the SC \Roman{u-large} for $U<U'$, in the wide parameter region including both weak and strong correlation regimes. Pairing correlation functions indicate that the most dominant pairing for the SC \Roman{u'-large} (SC \Roman{u-large}) is the intersite (on-site) intraorbital spin-singlet with (without) sign reversal of the order parameters between two Fermi pockets. The result of the SC \Roman{u'-large} is consistent with the sign-reversing s-wave pairing that has recently been proposed for iron oxypnictide superconductors.Comment: 5 pages, 8 figures, to appear in J. Phys. Soc. Jpn., Vol.78, No.12, p.12470

Charge Gap in the One-Dimensional Extended Hubbard Model at Quarter Filling

We propose a new combined approach of the exact diagonalization, the renormalization group and the Bethe ansatz for precise estimates of the charge gap $\Delta$ in the one-dimensional extended Hubbard model with the onsite and the nearest-neighbor interactions $U$ and $V$ at quarter filling. This approach enables us to obtain the absolute value of $\Delta$ including the prefactor without ambiguity even in the critical regime of the metal-insulator transition (MIT) where $\Delta$ is exponentially small, beyond usual renormalization group methods and/or finite size scaling approaches. The detailed results of $\Delta$ down to of order of $10^{-10}$ near the MIT are shown as contour lines on the $U$-$V$ plane.Comment: 4 pages, 4 figure

Impact of Chronic Kidney Disease on the Presence and Severity of Aortic Stenosis in Patients at High Risk for Coronary Artery Disease

<p>Abstract</p> <p>Objective</p> <p>We evaluated the impact of chronic kidney disease (CKD) on the presence and severity of aortic stenosis (AS) in patients at high risk for coronary artery disease (CAD).</p> <p>Methods</p> <p>One hundred and twenty consecutive patients who underwent invasive coronary angiography were enrolled. Aortic valve area (AVA) was calculated by the continuity equation using transthoracic echocardiography, and was normalized by body surface area (AVA index).</p> <p>Results</p> <p>Among all 120 patients, 78% had CAD, 55% had CKD (stage 3: 81%; stage 4: 19%), and 34% had AS (AVA < 2.0cm²). Patients with AS were older, more often female, and had a higher frequency of CKD than those without AS, but the prevalence of CAD and most other coexisting conventional risk factors was similar between patients with and without AS. Multivariate linear regression analysis indicated that only CKD and CAD were independent determinants of AVA index with standardized coefficients of -0.37 and -0.28, respectively. When patients were divided into 3 groups (group 1: absence of CKD and CAD, n = 16; group 2: presence of either CKD or CAD, n = 51; and group 3: presence of both CKD and CAD, n = 53), group 3 had the smallest AVA index (1.19 ± 0.30*# cm²/m², *p < 0.05 vs. group 1: 1.65 ± 0.32 cm²/m², and #p < 0.05 vs. group 2: 1.43 ± 0.29* cm²/m²) and the highest peak velocity across the aortic valve (1.53 ± 0.41*# m/sec; *p < 0.05 vs. group 1: 1.28 ± 0.29 m/sec, and #p < 0.05 vs. group 2: 1.35 ± 0.27 m/sec).</p> <p>Conclusion</p> <p>CKD, even pre-stage 5 CKD, has a more powerful impact on the presence and severity of AS than other conventional risk factors for atherosclerosis in patients at high risk for CAD.</p

Structure and evolution of the mouse pregnancy-specific glycoprotein (Psg) gene locus

BACKGROUND: The pregnancy-specific glycoprotein (Psg) genes encode proteins of unknown function, and are members of the carcinoembryonic antigen (Cea) gene family, which is a member of the immunoglobulin gene (Ig) superfamily. In rodents and primates, but not in artiodactyls (even-toed ungulates / hoofed mammals), there have been independent expansions of the Psg gene family, with all members expressed exclusively in placental trophoblast cells. For the mouse Psg genes, we sought to determine the genomic organisation of the locus, the expression profiles of the various family members, and the evolution of exon structure, to attempt to reconstruct the evolutionary history of this locus, and to determine whether expansion of the gene family has been driven by selection for increased gene dosage, or diversification of function. RESULTS: We collated the mouse Psg gene sequences currently in the public genome and expressed-sequence tag (EST) databases and used systematic BLAST searches to generate complete sequences for all known mouse Psg genes. We identified a novel family member, Psg31, which is similar to Psg30 but, uniquely amongst mouse Psg genes, has a duplicated N1 domain. We also identified a novel splice variant of Psg16 (bCEA). We show that Psg24 and Psg30 / Psg31 have independently undergone expansion of N-domain number. By mapping BAC, YAC and cosmid clones we described two clusters of Psg genes, which we linked and oriented using fluorescent in situ hybridisation (FISH). Comparison of our Psg locus map with the public mouse genome database indicates good agreement in overall structure and further elucidates gene order. Expression levels of Psg genes in placentas of different developmental stages revealed dramatic differences in the developmental expression profile of individual family members. CONCLUSION: We have combined existing information, and provide new information concerning the evolution of mouse Psg exon organization, the mouse Psg genomic locus structure, and the expression patterns of individual Psg genes. This information will facilitate functional studies of this complex gene family

In Vivo

In vivo real-time visualization of the process of angiogenesis in secondary tumors in the same living animals presents a major challenge in metastasis research. We developed a technique for intravital imaging of colorectal liver metastasis development in live mice using two-photon laser scanning microscopy (TPLSM). We also developed time-series TPLSM in which intravital TPLSM procedures were performed several times over periods of days to months. Red fluorescent protein-expressing colorectal cancer cells were inoculated into the spleens of green fluorescent protein-expressing mice. First- and second-round intravital TPLSM allowed visualization of viable cancer cells (red) in hepatic sinusoids or the space of Disse. Third-round intravital TPLSM demonstrated liver metastatic colonies consisting of viable cancer cells and surrounding stroma with tumor vessels (green). In vivo time-course imaging of tumor angiogenesis in the same living mice using time-series TPLSM could be an ideal tool for antiangiogenic drug evaluation, reducing the effects of interindividual variation

Prevalence of Self-Reported Shaking and Smothering and Their Associations with Co-Sleeping among 4-Month-Old Infants in Japan

Few studies have investigated the prevalence of shaking and smothering and whether they are associated with co-sleeping. In Japan, co-sleeping is common during infancy and early childhood. This study investigates the prevalence of shaking and smothering and their associations with co-sleeping among 4-month-old infants in Japan. A questionnaire was administered to mothers who participated in a 4-month health checkup program in Kamagaya City in Japan (n = 1307; valid response rate, 82%). The questionnaire investigated the frequency of self-reported shaking and smothering during the past one month, co-sleeping status, and living arrangements with grandparents, in addition to traditional risk factors such as stress due to crying. Associations between co-sleeping and self-reported shaking or smothering were analyzed using multiple logistic regression. The prevalence of self-reported shaking and smothering at least one time during the past one month was 3.4% (95% confidence interval (CI), 2.4%–4.3%) and 2.4% (95% CI, 1.5%–3.2%), respectively. Co-sleeping was marginally associated with the amount of crying and not associated with stress due to crying. Further, co-sleeping was not associated with either self-reported shaking or smothering, although stress due to crying showed strong association with shaking and smothering. Co-sleeping was not a risk factor for shaking and smothering

ヘテロジニアスマルチプロセッサに対応したコヒーレンシシステムの設計手法に関する研究

三重大学大学院 工学研究科 博士前期課程 情報工学専攻 計算機アーキテクチャ研究室近年，高性能と低消費電力を両立する手法として，構成の異なる複数のプロセッサコアによって構成されるヘテロジニアスマルチコアプロセッサが注目を集めている．従来のホモジニアスマルチコアプロセッサでは，構成の同じコアを搭載しているため，各アプリケーションに対して全て同じリソースが割り当てられ，性能の過不足により，無駄な消費電力が発生する．ヘテロジニアスマルチコアプロセッサでは，各アプリケーションに対して，最適な構成を持つコアを割り当てることによって，このような無駄な消費電力を抑えて，より高い電力効率を達成することができる．一方で，ヘテロジニアスマルチコアプロセッサは，構成の異なるコア，キャッシュとそれぞれに対応したバスシステムが必要であり，それぞれに別の設計・検証が必要になることから，従来手法と比較して設計コストが高く，ヘテロジニアスマルチコアプロセッサを研究・開発する上での大きな障害となっている．この問題を解決するために，自動設計技術が研究されており，著者らの研究グループでは，様々な構成のヘテロジニアスマルチコアプロセッサを自動設計するツールとして，FabHeteroを提案している．FabHeteroは，並列度やキャッシュサイズのような要求仕様をパラメータとして与えることで，ヘテロジニアスマルチコアプロセッサを自動設計することを目指している．しかし，現状のFabHeteroはキャッシュコヒーレンシ機構が実装されていない．そのため，本研究ではFabHetero上にキャッシュコヒーレンシ機構を実装することで，より現実的な設計ツールを実現する．しかしながら，自動設計ツールにおいてキャッシュコヒーレンシをサポートするバスシステムの設計は，その構成や回路が要求仕様や設計条件等により多様に変化するため，自動化のための大きな課題の一つとなる．この問題の一つとしては，キャッシュやコアがそれぞれの仕様に従って内部で完結するのに対して，バスシステムはそれらを相互接続するために，それぞれのキャッシュやコアの異なる仕様に起因するプロトコル・バス幅の違いなどの問題を解決する必要があることが挙げられる．更に，ただ１つの仕様の変更に伴ってバスシステム全体の設計が変わることから，接続するコアが増えたり，仕様の可変要素が増えることに伴って，解決する必要がある要素が指数関数的に増えていく．このため，全ての組み合わせに対応して設計データを作る，といった手法は事実上不可能であり，どの仕様の違いを設計のどの部分で解決するか，という課題を解決する必要がある．本研究では，これらの問題を解決するために，ヘテロジニアスマルチコアプロセッサ上でのキャッシュコヒーレンシをサポートするバスシステムの設計のためのデザインフレームワークを提案する．具体的には，上述の問題に対して，設計のどの部分を共通化するか，仕様の違いを設計のどの部分で吸収するかのベースとなる構成をフレームワークとして与えることで，組み合わせ問題の分割，設計データの共有化率の向上を図り，ヘテロジニアスマルチコアプロセッサの設計，自動設計ツールの開発の効率化を目指すものである．更に，本論文では提案フレームワークの有効性を示すために，提案フレームワークを含むバスシステムの自動設計ツールを実装し，その動作検証を行った．その結果，ソースコードの重複量や修正する必要のあるコード量について，FabHeteroを用いて構成した典型的な2階層のキャッシュシステムで約22％削減できた．又，SPEC2000INTベンチマークを用いて，提案したフレームワークをベースに，FabHetero上に実装したキャッシュコヒーレンシ機構の動作検証を行い，正しく動作していることを確認した．$$Single-ISA heterogeneous multi-core processor architecture which is composed of diverse cores, cache systems, and share bus system is promising technique to achieve higher energy efficiency. However, because a designer must design and verify each of cores, caches and shared bus system of heterogeneous multi-core processor (HMP), an effort of implementing HMP is multiplied by the number of kinds of each of component. This limits an amount of microarchitectural diversity of commercial or research products which can be practically implemented due to a limitation of a resource and time to implement. In order to reduce the efforts, many researches have focused on design automation technology. Then, we proposes FabHetero which is an automatic generation toolset of HMP. However, the current FabHetero does not have a cache coherency mechanism. Therefore, this study implements a cache coherency logic on FabHetero for developing it. Nevertheless, generating of shared bus interconnection with supporting cache coherency mechanism of HMP is one of the major challenge to implement an automatic generation system of HMP. As a reason for this, a bus system of HMP have to resolve differences of connecting elements caused by micro-architectural differences of each core and cache. In addition, a number of this differences increases exponentially along with a number of connecting elements or modification of specification. And then, a number of combination is too enormous to support all of cases. This is a barrier to develop and reserach of HMP and its design tool. In this study, to the barrier, this paper proposes a framework which shows a implementation strategy or policy of cache coherent system and bus system under HMP environment for making efficiency of developing an automation design tool and implementing a HMP. As the first step to develop and verify this framework, this papr also implemented an automatic generating system of snoop-based interconnection using FabHetero ported to ARM AMBA4 and ACE protocol. In the result, this study succeeds to reduce about 22% redundant HDL codes of HMP generated by FabHetero, and therefore, this study can reduce implementation effort about 2 to 4 man-month out of developing entire multi-core processor. In addition, this study verify the implemented system correctly works on SPEC2000INT benchmarks

褐藻ツルアラメの生長と繁殖におよぼす水温の影響

三重大学大学院 生物資源学研究科 博士前期課程 生物圏生命科学専攻 海洋生物科学講座コンブ目に属する大型褐藻であるツルアラメは，主に日本海沿岸部の水深2-10mの岩盤上に生育し，海中林とよばれる密な群落を形成する水産的・生産的に重要な種である。大型藻類は水平分布が主に水温によって制限されるため，地球温暖化による水温上昇の影響を受けると考えられる。しかし，これまで行われてきた大型藻類の温度特性は2-5℃刻みの温度条件で研究されたものが多く，地球温暖化の海水温の上昇率から考えると大型藻類への影響を評価する上では不十分であった。ツルアラメは大型の胞子体世代と，微小の配偶体世代をもっており，異形世代交代を行うため，温暖化の影響を評価するためには生活史全体についての詳しい温度特性を明らかにする必要がある。そこで本研究ではツルアラメの配偶体および幼胞子体を用いて生長・繁殖についての1℃刻みの詳細な温度特性実験を行い，地球温暖化の影響を評価する上での基礎的知見の蓄積を目的として研究を行った。その結果，ツルアラメ雌雄配偶体の生長上限温度は28℃，雌雄配偶体の成熟上限温度は25℃，また，幼胞子体の生長上限温度は27℃，成熟上限温度は23℃以下，栄養繁殖の上限温度は25℃であった。他の日本産多年生暖海性コンブ目藻類の水平分布と日本近海の夏季の表面海水温データを比較すると，夏季の28℃の等温線と各種の分布域の南限がほぼ一致していた。このことから，夏季の高水温はこれらの藻類の分布南限の主要な制限要因であると考えられ，地球温暖化による海水温の上昇は将来的にこれらの藻類の水平分布に重大な影響を与える可能性があると考えられた。今後，地球温暖化の影響をより詳細に評価するためには，異なる光周期での高温耐性や低温に対する温度特性，さらに弱光下など異なる環境条件化でのより詳細な生理・生態学的な研究を行う必要がある。これまで明らかにされてきた日本産暖海性コンブ目海藻の温度特性についての知見により，温暖化が進行した場合の分布域の変化予測がある程度可能となった

カチオン性界面活性剤存在下でのシリカによるPickering エマルションの特性評価

三重大学大学院 工学研究科 博士前期課程 分子素材工学専攻 有機素材化学研究

省電力マイコンを想定した移動透過及び通信接続技術に関する研究

三重大学大学院 工学研究科 博士課程前期 電気電子工学専攻 通信工学研究