Superconductivity in undoped T' cuprates with Tc over 30 K

Undoped cuprates have long been considered to be antiferromagnetic insulators. In this article, however, we report that superconductivity is achieved in undoped T'-RE2CuO4 (RE = Pr, Nd, Sm, Eu, and Gd). Our discovery was performed by using metal-organic decomposition (MOD), an inexpensive and easy-to-implement thin-film process. The keys to prepare the superconducting films are firing with low partial-pressure of oxygen and reduction at low temperatures. The highest Tc of undoped T'-RE2CuO4 is over 30 K, substantially higher than "electron-doped" analogs. Remarkably, Gd2CuO4, even the derivatives of which have not shown superconductivity so far, gets superconducting with Tconset as high as ~ 20 K. The implication of our discovery is briefly discussed.Comment: 22 pages, 5 figures, submitted to Physical Review Letter

Coenzyme Models 27 Degradative Oxidation of Glyoxals to Carboxylic Acids Mediated by Flavin and Cyanide Ion

In an aerobic aqueous solution containing flavin and cyanide ion, phenylglyoxal and 4-chlorophenylglyoxal were easily oxidized to benzoic acid and 4-chlorobenzoic acid, respectively (49-61 % yield). The product analysis indicates that the initial step (ArCOCHO → ArCOCO2 H) is the "Flavin-trapping" mediated by flavin and cyanide ion and the second step (ArCOCO2 H → ArCO2H) is the oxidation by hydrogen peroxide which is yielded through the pingpong-type regeneration of flavin. Methylglyoxal was also oxidized degradatively to acetic acid. The oxidation of glyoxal was more complicated: oxalic acid was afforded in the nonmicellar system, while formic acid was the sole detectable product in the CTAB micellar system. The reactions reported here demonstrate a novel facet of flavin catalyses

Kinetics and Isotope Effects for Transhydrogenation from a NADH Model Compound to Flavins

Kinetics and isotope effects for the reaction of a Hantzsch ester and a monodeuteriated Hantzsch ester with five isoalloxazines have been studied. The kinetic deuterium isotope effect (kH/kD) for "usual" isoalloxazines is in good accord with the paritioning isotope effect (YH/YD) and the secondary isotope effect (kH/k\u27H) is almost equal to unity. On the other hand, kH/kD for electron-deficient isoalloxazines is greater than YH/Y\u27H, and kH/k\u27H significantly exceeds unity. The results suggest that one-step hydride-like transfer occurs in "usual" isoalloxazines, whereas hydrogen transfer to electron-deficient isoalloxazines may proceed according to the multi-step transfer mechnism. We thus consider that the hydrogen transfer mechanism changes depending on the electron-dificiency of inoalloxazines, although the possibility that the isotope scrambling is responsible for the discrepancy is not excluded completely

Facile Photo-Oxidation of Alcohols by a Flavin with a Metal-Chelation Site

A new flavin molecule with a metal-chelation site has been applied to photo-oxidation of alcohols: it is 2, 4, 7-trimethyl-10-benzylquino [8, 7-g] pteridine-9, 11 (7H, 10H) -dione (1) which has both an isoalloxazine structure and a phenathroline-like structure within a molecule. In contrast to conventional flavins which do not exhibit any measurable affinity toward redox-inactive transition metal ions, 1 formed stable complexes with most heavy metal ions in acetonitrile probably by means of a flavin → metal charge transfer. Photooxidation of alcohols by 1 was efficiently accelerated in the presence of Mg(II) and Zn(II), the k1 (pseudo-first-order rate constant) being greater by 5.1-7l fold than those in the absence of metal ions. Such a marked rate increase was not observed for 3-methyl-10-ethylisoalloxazine used as a reference flavin. The aerobic photo-oxidation of benzyl alcohol by the 1・Zn(II) complex served as a light-mediated recycle oxidation catalyst. These results indicate that the flavin with a metal-chelation site is not only useful synthetically as a recycle-type oxidation catalyst but also capable of mimicking the flavin-metal interactions important in metalloflavoproteins

Symmetrical Skin Lesions on the Gluteal Region in a Patient with Anti-Laminin-332 Mucous Membrane Pemphigoid

Mucous membrane pemphigoid (MMP), previously called cicatricial pemphigoid, is a rare subepidermal immunobullous disorder that primarily affects the mucous membranes (1,2). MMP is divided into two major subtypes, anti-BP180-type MMP and anti-laminin-332 (previously called laminin 5 or epiligrin) MMP. Anti-laminin-332 MMP is known to be associated with malignant tumors (3), which may cause overexpression of autoantibodies and induce autoimmunity to laminin-332 (4). MMP primarily affects the mucous membranes, and widespread skin lesions are rare. In MMP, circumscribed skin lesions have been previously reported as occurring on the head, neck, and upper trunk (5). We report a case of anti-laminin-332 MMP presenting with symmetrical skin lesions characteristic of MMP on the weightbearing areas of the gluteal regio

Renal cell carcinoma with a tumor thrombus in the ureter: a case report

<p>Abstract</p> <p>Background</p> <p>Renal cell carcinoma (RCCs) is the most common malignancy of the kidney. When RCC progresses, it is known to form tumor thrombus in the renal vein and/or inferior vena cava. However, RCC does not normally form tumor thrombus in the ureter or renal pelvis.</p> <p>Case presentation</p> <p>A 43-year-old man presented to our department for the treatment of a renal tumor with asymptomatic gross hematuria. In a dynamic CT study, contrast enhancement revealed a tumor suspected to be RCC, but atypical finding as a tumor thrombus that filled the renal pelvis and the whole ureter was also observed. Nephroureterectomy was performed, and the tumor was diagnosed histopathologically as RCC.</p> <p>Conclusion</p> <p>We report here a very rare case of RCC with a tumor thrombus in the whole ureter.</p

Paraproteinemia in a Patient with Acute Myelogenous Leukemia Derived from the Myelodysplastic Syndrome : A Case Report

Severe paraproteinemia was found in a 75-year-old female with acute myelogenous leukemia (AML) derived from refractory anemia with an excess of blasts, a type of the myelodysplastic syndrome (MDS). Immunoglobulin G-κ and G-λ paraproteins had increased in accordance with the proliferation of myeloblasts in her bone marrow. When the diagnosis of AML was made, a severe bleeding tendency and disturbance of consciousness due to the hyperviscosity syndrome were noted, although there was no significant increase in plasma cells in her bone marrow. An ultrasonogram disclosed multiple hyperechoic nodular lesions in the spleen. Cytoreductive therapy for AML was begun after plasma exchange, but she died of acute renal failure, subarachnoid hemorrhage, and the disseminated intravascular coagulation syndrome. Autopsy findings revealed clusters of plasma cells in the spleen and lymph nodes. The possibility that this coexistant paraproteinemia and AML were related to the evolution of a transformed clone in MDS is discussed

Astrometry of Water Maser Sources in Nearby Molecular Clouds with VERA - II. SVS 13 in NGC 1333

We report on the results of multi-epoch VLBI observations with VERA (VLBI Exploration of Radio Astrometry) of the 22 GHz H2O masers associated with the young stellar object SVS 13 in the NGC 1333 region. We have carried out phase-referencing VLBI astrometry and measured an annual parallax of the maser features in SVS 13 of 4.25+/-0.32 mas, corresponding to the distance of 235+/-18 pc from the Sun. Our result is consistent with a photometric distance of 220 pc previously reported. Even though the maser features were detectable only for 6 months, the present results provide the distance to NGC 1333 with much higher accuracy than photometric methods. The absolute positions and proper motions have been derived, revealing that the H2O masers with the LSR (local standard of rest) velocities of 7-8 km s-1 are most likely associated with VLA4A, which is a radio counterpart of SVS 13. The origin of the observed proper motions of the maser features are currently difficult to attribute to either the jet or the rotating circumstellar disk associated with VLA4A, which should be investigated through future high-resolution astrometric observations of VLA4A and other radio sources in NGC 1333.Comment: 9 pages, 5 figures. PASJ, in press (2008, Vol. 60, No. 1