TIME-LIKE AND SPACE-LIKE CURVES IN FRENET-SERRET FORMALISMS.

The Frenet-Serret formalism for both time-like and space-like curves is studied. The Frenet-Serret vectors and the Frenet-Serret coefficients in both three and four dimensions are expressed in terms of world quantities. The conversion from the three dimensional Frenet-Serret formalism to the four dimensional Frenet-Serret formalism and vice versa is described. Indicators of the four dimensional Frenet-Serret vector are investigated. The Frenet-Serret equations in both three and four dimensions are solved for constant Frenet-Serret coefficients with arbitrary initial conditions. Nulltetrads, spinors, bispinors, spinor adjoint and bispinor adjoint are then defined. The Frenet-Serret equations for the nulltetrads, the spinors, the bispinors and the bispinor adjoints are introduced. Darboux bivector forms of the Frenet-Serret equations for the orthonormal tetrads and the nulltetrads are derived. Darboux bispinor forms of the Frenet-Serret equations for the spinors and the bispinor adjoints are derived. Solutions for the nulltetrads and the Darboux bivectors and the Darboux dispinors are discussed. Motion of a point charge in electromagnetic field and motion of a freely spinning particle are briefly discussed. Most of the foregoing are duplicated for the skew-symmetrized descriptions. Examples of the above analysis are given for the time-like curve and the space-like curve with indicators ((epsilon)(,2) = -1, (epsilon)(,0) = (epsilon)(,1) = (epsilon)(,3) = 1). The former is picked in order to compare with the existing literature and the latter is chosen as the simplest case of space-like curves.Dept. of Physics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1985 .I345. Source: Dissertation Abstracts International, Volume: 46-09, Section: B, page: 3086. Thesis (Ph.D.)--University of Windsor (Canada), 1985

Computed tomography detection of stapled interlobar fissure facilitates diagnosing postoperative lobar torsion: A case report

IntroductionAtelectasis of the right middle lobe following right upper lobectomy may result from lobar torsion, bronchial kink, or impacted mucus plug. Although clinical consequence of lobar torsion could be serious, differentiating it from bronchial kink is occasionally challenging.Presentation of caseA 39-year old man with non-small cell lung cancer of cT1aN0M0 stage IA underwent right upper lobectomy. On postoperative day 1, we identified middle lobe atelectasis on the chest X-ray and performed bronchoscopy, which showed an obstruction of the right middle lobe bronchus without mucoid impaction. We injected air using a bronchoscope to the middle lobe, which re-expanded it. However, on postoperative day 2, chest X-ray showed a slightly collapsed and opacified middle lobe. Although enhanced computed tomography showed a patent middle lobe pulmonary artery, we noticed that a staple placed in the horizontal fissure was in contact with the lower lobe, implying the possibility of lobar torsion. Rethoracotomy on postoperative day 2 revealed a 240° clockwise rotation of the congested middle lobe. Therefore, we performed simple detorsion. The patient was discharged 10 days after rethoracotomy without further adverse events.DiscussionIn our case, patency of the pulmonary artery and temporary improvement of the atelectasis using a bronchoscopic aeration maneuver could not rule out the possibility of lobar torsion.ConclusionThe position of the staple placed on the interlobar fissure should be evaluated using computed tomography in postoperative middle lobe atelectasis. If the aeration maneuver for middle lobe atelectasis using bronchoscope fails, rethoracotomy should be considered

膵癌における癌遺伝子および癌抑制遺伝子

Recent advances in molecular biology have revealed that a number of oncogenes (K-ras, erbB-2, and Met) and tumor suppressor genes (p53, p16, APC, and DCC) contribute to the development of pancreatic cancer. This paper reviewed the present knowledge of oncogenes and tumor suppressor genes relevant to pancreatic cancer. Further studies on molecular alterations in pancreatic cancer may lead to a better understanding of tumor biology, offering a possibility of development of new diagnostic and therapeutic approaches in the future.膵癌の予後は惨憺たるものである｡一方で,最近の分子生物学の分野での研究の進歩により,遺伝子レベルでの異常が膵癌では数多く存在することも明らかになってきた｡膵癌の予後を改善するために,発展が期待される膵癌における遺伝子診断や遺伝子治療に向けて現在までの膵癌で明らかになった癌遺伝子(k-ras,erbB-2,Met),癌抑制遺伝子(p53,p16,APC,DDC)について,概説した

Experimental model of chronic pancreatitis, a review - Does it really exist?

Experimental model of pancreatitis is mandatory for elucidating the pathobiology of the disease and also to see the response of a novel treatment. In addition, the need for an animal model of chronic pancreatitis is further strengthened by the relative inaccessibility and paucity of the human pancreatitis tissue. Whereas various models of acute pancreatitis and also of exocrine pancreatic tumor have been described, chronic pancr-eatitis has not been consistently reproduced in experimental animals. Many researchers attempted to establish an experimental model of chronic pancreatitis either by partially obstructing the drainage of pancreatic secretion in dogs and cats or by feeding alcohol to dogs and rats with and without temporary occlusion of the biliopancreatic duct or by surgically inducing ischaemia in the pancreas of the dogs. But, none of these models is identical with human disease. A consistently reproducible model of human chronic pancr-eatitis probably does not exist. In this expanding era of molecular biology which promises us to enhance greatly our understanding of this disease, a right experimental model of chronic pancreatitis is still in progress.疾患の実験モデルの作成は,その疾患の病因,病態の解明,さらに治療法の開発のために重要である｡筆者らの一人は厚生省難治性膵疾患調査研究班の班員として,慢性膵炎の病態の解明や治療法の開発に関する研究を行っており,その研究の一環として,慢性膵炎の実験モデルの作成を現在行っている｡そこで,これまで報告されている慢性膵炎の実験モデルについて概要を報告した｡種々の動物や方法でヒト慢性膵炎に病因,病態,組織像が類似するモデルの作成が試みられてきたが,そのすべてが合致するような慢性膵炎モデルは確 立されてはいない｡近年の分子生物学的研究の進歩は著しく,実験モデルへの応用が種々なされている現在,より簡便で再現性のある慢性膵炎モデルの作成が望まれるところである

Ferromagnetism in a Hubbard model for an atomic quantum wire: a realization of flat-band magnetism from even-membered rings

We have examined a Hubbard model on a chain of squares, which was proposed by Yajima et al as a model of an atomic quantum wire As/Si(100), to show that the flat-band ferromagnetism according to a kind of Mielke-Tasaki mechanism should be realized for an appropriate band filling in such a non-frustrated lattice. Reflecting the fact that the flat band is not a bottom one, the ferromagnetism vanishes, rather than intensified, as the Hubbard U is increased. The exact diagonalization method is used to show that the critical value of U is in a realistic range. We also discussed the robustness of the magnetism against the degradation of the flatness of the band.Comment: misleading terms and expressions are corrected, 4 pages, RevTex, 5 figures in Postscript, to be published in Phys. Rev. B (rapid communication

Current-induced magnetization switching in MgO barrier magnetic tunnel junctions with CoFeB based synthetic ferrimagnetic free layers

We investigated the effect of using a synthetic ferrimagnetic (SyF) free layer in MgO-based magnetic tunnel junctions (MTJs) on current-induced magnetization switching (CIMS), particularly for application to spin-transfer torque random access memory (SPRAM). The employed SyF free layer had a Co40Fe40B20/ Ru/ Co40Fe40B20 and Co20Fe60B20/Ru/Co20Fe60B20 structures, and the MTJs(100x(150-300) nm^2) were annealed at 300oC. The use of SyF free layer resulted in low intrinsic critical current density (Jc0) without degrading the thermal-stability factor (E/kBT, where E, kB, and T are the energy potential, the Boltzmann constant, and temperature,respectively). When the two CoFeB layers of a strongly antiferromagnetically coupled SyF free layer had the same thickness, Jc0 was reduced to 2-4x10^6 A/cm^2. This low Jc0 may be due to the decreased effective volume under the large spin accumulation at the CoFeB/Ru. The E/kBT was over 60, resulting in a retention time of over ten years and suppression of the write current dispersion for SPRAM. The use of the SyF free layer also resulted in a bistable (parallel/antiparallel) magnetization configuration at zero field, enabling the realization of CIMS without the need to apply external fields to compensate for the offset field.Comment: 6 page

Fusarium phytotoxin trichothecenes have an elicitor-like activity in Arabidopsis thaliana, but the activity differed significantly among their molecular species

金沢大学学際科学実験センター遺伝子研究施設Phytopathogenic fungi such as Fusarium spp. synthesize trichothecene family phytotoxins. Although the type B trichothecene, deoxynivalenol (DON), is thought to be a virulence factor allowing infection of plants by their trichothecene-producing Fusarium spp., little is known about effects of trichothecenes on the defense response in host plants. Therefore, in this article, we investigated these effects of various trichothecenes in Fusarium-susceptible Arabidopsis thaliana. Necrotic lesions were observed in Arabidopsis leaves infiltrated by 1 μM type A trichothecenes such as T-2 toxin. Trichothecene-induced lesions exhibited dead cells, callose deposition, generation of hydrogen peroxide, and accumulation of salicylic acids. Moreover, infiltration by trichothecenes caused rapid and prolonged activation of two mitogen-activated protein kinases and induced expression of both PR-1 and PDF1.2 genes. Thus, type A trichothecenes trigger the cell death by activation of an elicitor-like signaling pathway in Arabidopsis. Although DON did not have such an activity even at 10 μM, translational inhibition by DON was observed at concentrations above 5 μM. These results suggested that DON is capable of inhibiting translation in Arabidopsis cells without induction of the elicitor-like signaling pathway. © 2006 The American Phytopathological Society.

Endoscopic aspiration of pure pancreatic juice is useful in diagnosis and treatment of chronic pancreatitis.

内視鏡的純粋膵液採取法の慢性膵炎診療における意義を検討した｡本法を用い,セクレパン100単位静注後10分間膵液を採取するintaraductal secretin test(IDST,膵管内セクレチン試験)はこれまで膵外分泌機能検査のgold standardである十二指腸液を採取するセクレチン試験に代用ができ,しかも10分間の採取時間で終了する利点を有する｡本法を施行することにより,蛋白栓が除去され,痔痛の消失に有用である｡また,慢性膵炎と鑑別を要する膵癌を除外診断するために,本法によって採取した膵液の細胞診,腫瘍マーカー,癌遺伝子の検出は有用である｡Endoscopical aspiration of pure pancreatic juice is useful in following aspects. Firstly, intraductal secretin test by using this method can be substituted for duodenal secretin test, which is a gold standard examination for estimation of exocrine pancreatic function. In addition, endoscopic aspiration of protein pluge eliminates abdominal pain of some painful patients with chronic pancreatitis. Cytological examination, determination of tumor marker, and detection of oncogene in the obtained pancreatic juice are complementary diagnostic approach to pancreatic cancer, which must be differentially diagnosed from chronic pancreatitis

Concise total syntheses of phelligridins A, C, and D

We have established a concise and scalable synthetic pathway for phelligridins A (1), C (2) and D (3). The synthetic highlights were Suzuki–Miyaura coupling and aldol-type condensation of α-pyrone. Phelligridin A was synthesized in four steps, while phelligridins C and D were each synthesized in six steps. Furthermore, we have revealed that the whole structure is essential for the cytotoxicity of phelligridins

Mechanisms of pancreatic fibrosis

膵の線維化は慢性膵炎に特徴的な病理組織所見の一つであるが,その発生機序については不明な点か多い｡慢性膵炎はいったん発症すれば,進行性かつ非可逆性であるとされるが,その非可逆性に膵の線維化が関与するとされる｡膵の線維化の発生機序を明らかにし,線維化に対する根本的な治療法の確立が望まれるところである｡そこで,本稿では今後の膵の線維化の研究課題を明らかにする目的で,現在までの膵臓線維化の発生機序に関する知見を整理した｡Pancreatic fibrosis is an outstanding morphological feature in chronic pancreatis although it is seen in pancreatic cancer and convalescent stage of acute pancreatitis. Progressive fibrosis in chronic pancreatitis leads to the destruction and contributes to irreversiblity of chronic pancreatitis. Exact mechanisms of pancreatic fibrosis is not yet unclear, although advances in molecular biology have revealed possible roles of cytokines and growth factors in it. We summarized our understanding of pancreatic fibrosis in the revIew