Maxwell Theory from Matrix Model

We present a scenario for deriving Maxwell theory from IIB matrix model. Four dimensional spacetime and theories on it relate different dimensional ones by applying appropriate limits of the backgrounds of matrix model. It is understood by looking at open strings bits as bi-local fields on the spacetime, which are decoupled from the bulk in the limits. The origin of electric-magnetic duality is also discussed in matrix model.Comment: Lattice 2000 (Gravity and Matrix Models), 4 page

Total synthesis of (±)-stemonamide, (±)-isostemonamide, (±)-stemonamine, and (±)-isostemonamine using a radical cascade

金沢大学医薬保健研究域薬学系A total synthesis of (±)-stemonamide and (±)-isostemonamide has been achieved by using a radical cascade that involves two endo-selective cyclizations. (±)-Stemonamine and (±)-isostemonamine are synthesized by chemoselective reduction of (±)-stemonamide and (±)-isostemonamide, respectively. © 2008 Elsevier Ltd. All rights reserved

Accuracy of Length of Virtual Stents in Treatment of Intracranial Wide-Necked Aneurysms.

Background and purposePrecise stent deployment is important for successful treatment of intracranial aneurysms by stent-assisted coiling (SAC). We evaluated the accuracy of virtual stents generated using commercial stent planning software by comparing the length of virtual and actually deployed intracranial laser cut stents on three-dimensional digital subtraction angiography (3D-DSA) images.MethodsWe retrospectively analyzed the data of 75 consecutive cases of intracranial wide-necked aneurysms treated with the SAC technique using laser cut stents. Based on 3D-DSA images acquired by C-arm CT, stent sizing and placement were intraoperatively simulated by a commercial software application. The difference in length of the stents was estimated by measuring proximal discrepancies between the end points of the virtual and actually deployed stents on fused pre-procedural and post-procedural 3D-DSA images. Discrepancies between distal stent end points were manually minimized. The Kruskal-Wallis test was applied to test whether stent location, type, and length had an effect on difference in length between virtual and real stent.ResultsThe median difference in length between virtual and real stents was 1.58 mm with interquartile range 1.12-2.12 mm. There was no evidence for an effect of stent location (p = 0.23), stent type (p = 0.33), or stent length (p = 0.53) on difference in length between virtual and real stents.ConclusionsStent planning software allows 3D simulation of laser cut stents overlain on 3D-DSA images of vessels and may thus be useful for stent selection and deployment of laser cut stents during stent-assisted coiling of intracranial aneurysms

Estimated pretreatment hemodynamic prognostic factors of aneurysm recurrence after endovascular embolization.

BACKGROUND:Hemodynamic factors play important roles in aneurysm recurrence after endovascular treatment. OBJECTIVE:Predicting the risk of recurrence by hemodynamic analysis using an untreated aneurysm model is important because such prediction is required before treatment. METHODS:We retrospectively analyzed hemodynamic factors associated with aneurysm recurrence from pretreatment models of five recurrent and five stable posterior communicating artery (Pcom) aneurysms with no significant differences in aneurysm volume, coil packing density, or sizes of the dome, neck, or Pcom. Hemodynamic factors of velocity ratio, flow rate, pressure ratio, and wall shear stress were investigated. RESULTS:Among the hemodynamic factors investigated, velocity ratio and flow rate of the Pcom showed significant differences between the recurrence group and stable group (0.630 ± 0.062 and 0.926 ± 0.051, P= 0.016; 56.4 ± 8.9 and 121.6 ± 6.7, P= 0.008, respectively). CONCLUSIONS:Our results suggest that hemodynamic factors may be associated with aneurysm recurrence among Pcom aneurysms. Velocity and flow rate in the Pcom may be a pretreatment prognostic factor for aneurysm recurrence after endovascular treatment

Causal Dynamical Triangulation with Extended Interactions in 1+1 Dimensions

We study the Causal Dynamical Triangulation (CDT) with extended interactions in 1+1 dimensions applying the method in the non-critical string field theory (SFT) constructed by Ishibashi and Kawai. For this model, we solve Schwinger-Dyson's equation (SDE) for disk amplitude perturbatively, and find a matrix model in the continuum limit reproducing the SDE in the non-critical SFT approach as the loop equation.Comment: 16 pages, 4 figure

実用的ラジカル反応の開発と生理活性化合物合成への応用

1.エナミドオレフィンに対する6-endo選択的アリールラジカル環化反応と、生じたアミドイルラジカルの5-endo環化反応を組み合わせたラジカルカスケードにより、13位にメチル基を有するフェナンスロインドリジジン類の簡便合成法を明らかにした。 2.エナミドオレフィンに対する6-endo選択的アルキルラジカル環化反応と、生じたアミドイルラジカルの5-endo環化反応を組み合わせたラジカルカスケードにより、シリンドリシン類の簡便構築法を明らかにした。 3.エナミドオレフィンに対する7-endo選択的アリールラジカル環化反応と、生じたアミドイルラジカルの5-endo環化反応を組み合わせたラジカルカスケードにより、セファロタキシン骨格の簡便構築法を明らかにした。 4.エナミドオレフィンに対する7-endo選択的アリールラジカル環化反応と、生じたアミドイルラジカルの芳香族置換反応を組み合わせることにより、イソインドロベンズアゼピンアルカロイド、レンノキサミンの短工程合成法を明らかにした。 5.エナミドオレフィンに対する7-endo選択的アルキル環化反応と、生じたアミドイルラジカルの5-endo環化反応を組み合わせたラジカルカスケードを用いることにより、ステモナミド類の全合成を達成した。 6.N-アリル-α,α,α-トリクロロアセトアミド類が、溶媒として用いた1,4-ジメチルピペラジン中加熱するだけでsingle electron transfer反応を起こして1つのクロル基を脱離し、ラジカル環化反応に基づく成績体を与えることを見出した 7.エナミドオレフィンに対するアルキルラジカル環化反応のexo選択性とendo選択性について詳細に検討した。1. Radical cascade involving 6-endo selective cyclization of aryl radical onto olefinic bond of enamide and 5-endo cyclization of the resulting amidoyl radical afforded a convenient synthesis of phenanthroindolizidines containing a methyl group at their C13 position.2. Radical cascade involving 6-endo selective cyclization of alkyl radical onto olefinic bond of enamide and 5-endo cyclization of the resulting amidoyl radical afforded a convenient synthesis of cylindricine skeleton.3. Radical cascade involving 7-endo selective cyclization of aryl radical onto olefinic bond of enamide and 5-endo cyclization of the resulting amidoyl radical afforded a concise synthesis of cephalotoxine skeleton.4. Radical cascade involving 7-endo selective cyclization of aryl radical onto olefinic bond of enamide and homolytic aromatic substitution of the resulting amidoyl radical afforded a short synthesis of lennoxamine.5. Radical cascade involving 7-endo selective cyclization of alkyl radical onto olefinic bond of enamide and 5--endo cyclization of the resulting amidoyl radical afforded a total synthesis of stemonamide, isostemonamide, stemonamine, and isostemonamine.6. N-Allylic or N-vinylic, α, α, α-trichloroacetamides, upon heating in 1, 4-dimethylpiperazine, underwent radical cyclization to give the corresponding y-lactams.7. exo and endo Selectivities of aryl or alkyl radical onto olefinic bond of enamides were studied in detail.研究課題/領域番号:16390004, 研究期間(年度):2004–2006出典：「実用的ラジカル反応の開発と生理活性化合物合成への応用」研究成果報告書　課題番号16390004 (KAKEN：科学研究費助成事業データベース（国立情報学研究所）)　　　本文データは著者版報告書より作

Novel synthesis of 3-aminopropionitriles by ring opening of 2-oxazolidinones with cyanide ion

金沢大学医薬保健研究域薬学系Nucleophilic attack of cyanide ion on the 5-position of 2-oxazolidinones in the presence of 18-crown-6 gave 3-aminopropionitriles. © 2009 Elsevier Ltd. All rights reserved

新手法に基づくラジカル環化反応を利用する生理活性化合物の合成

ラジカル環化反応は環状化合物の新しい有用な合成手段として近年大きな注目を集めており、天然物合成を含む有機合成の領域において現在広く用いられている.しかし,この有用なラジカル環化反応にも解決すべき多くの課題が残されている.その一つは位置化学の制御である.一般に反応を制御しがたいラジカル反応において位置化学の制御の問題が解決されればラジカル反応の有用性はさらに増大するであろう.また,ラジカルの新しい発生法の開発も望まれている.そこで申請者らは,ラジカル環化反応におけるこれらの諸問題の解決を目指すとともに,これらの成果を生理活性化合物の効率的合成法と応用することを目的として本研究を開始し,下記の研究成果知見を得た. 1)硫黄原子によって制御された5-exo選択的アリールラジカルを利用して抗ヘルペスウイルス活性化合物Mappicine Ketoneの新しい合成法を明かにした.2)硫黄原子によって制御された6-exo選択的アリールラジカルを利用して鎮痛作用物質(-)-Aphanorphineの新しい合成法を明らかにした.3)2-位にフェニルチオ基またはフェニル基を有する種々のN-(1-シクロヘキセニル)-α-ハロアミド類のラジカル環化反応における5-endo及び4-exo選択性を明らかにした.4)α-アミドイルラジカルの5-endo型ラジカル環化反応を含む新しいカスケード型ラジカル環化反応を見い出した.5)N-ビニル-α-ハロアミドの5-endo型ラジカル環化反応においてヨウ素原子は脱離基として好ましくないことを明らかにした.6)α-メチルチオアセトアミドをII価の銅塩存在下酢酸マンガン(III)で処理することによりエリスリナン骨格の新しい合成法を見い出し,本反応を天然産エリスリナアルカロイド3-Demethoxyerythratidinoneの合成に応用した.Radical cyclization was recognized as a valuable tool for the construction of cyclic compounds, and the methods have been widely employed in the field of organic synthesis including natural products synthesis. However, there are many ploblems which required solvation in this useful radical cyclizations. One of them is the controlling regiochemistry. If this problem is solved, the radical cyclization would be highly promising. A new method for generation of radical species is also required. We, therefore, examined several radical cyclizations in more details, and found the following evidences.1)A new method for the synthesis of mappicine ketone, an antiherpesvirus compound, has been developed by using sulfur-directed 5-exo selective aryl radical cyclization. 2)A new method for the, synthesis of an analgesic(-)-aphanorphine has been developed by using sulfur-directed 6-exo selective aryl radical cyclization. 3)5-Endo and 4-exo selectivity in radical cyclization of N-(2-phenylthio and 2-phenyl-1-cyclohexenyl)-α-haloamides have been elucidated. 4)A radical cascade involving a 5-endo cyclization of α-amidoyl radicals has been found. 5)It was found that the use of iodine atom as a leaving group is not recommended for the 5-endo radical cyclization of N-vinylic α-haloamides. 6)A new synthesis of erythrinane skeleton which consisted of treatment of α-(methylthio)acetamides with Mn(OAc)_3 in the presence of Cu(II) was found, and the method was applied to the synthesis of 3-demethoxyerythratidinone, a naturally occurring Erythrina alkaloid.研究課題/領域番号:13470469, 研究期間(年度):2001–2003出典：「新手法に基づくラジカル環化反応を利用する生理活性化合物の合成」研究成果報告書　課題番号13470469 (KAKEN：科学研究費助成事業データベース（国立情報学研究所）)　　　本文データは著者版報告書より作