190 research outputs found

    Evidence for the singlet-dimer ground state in an S = 1 antiferromag netic bond alternating chain

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    Susceptibility, ESR and magnetization measurements have been performed on si ngle crystals of an S=1 bond alternating chain compound: [Ni(333-tet)(\mu-NO _2)](ClO_4) (333-tet = N,N'-bis(3-aminopropyl)propane-1,3-diamine) and the c ompound doped with a small amount of Zn. We observed an anomalous angular de pendence in the Zn-doped sample. These behaviors are well explained by the m odel based on the VBS picture for the singlet-dimer phase. The picture impli es that the free spins of S=1 with a positive single-ion anisotropy are indu ced at the edges of the chains without forming the singlet-dimer.Comment: RevTeX, 14pages (preprint.sty) with 5figures, submitted to Phys. R ev. Let

    Validating Quantitative Polymerase Chain Reaction Assay for the Molecular Diagnosis of Chronic Suppurative Otitis Media

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    BACKGROUND: Pathogen identification is critical for antibiotic selection in suppurative otitis media. However, bacterial culture challenges from suppurative specimens often cause antibiotic misuse and ineffective treatment. A quantitative polymerase chain reaction (PCR) controlled by the human cells contained in the specimen (HIRA-TAN) has been established in differentiate between pathogens and colonization in the previous pneumonia study. AIM: The aim of this study was to investigate the utility of HIRA-TAN and determine the causative pathogen in chronic suppurative otitis media. METHODS: Thirty-nine patients were recruited to the study. The otorrhea was swab-collected and processed for both bacterial culture and a multiplex PCR-based test. The cutoff of cycle threshold to determinate the pathogens was defined by receiver operating characteristic curves. RESULTS: Thirty-nine patients ranging from 1.7 to 62 years old were enrolled. The hearing impairment was found different between adult and children (p < 0.005) with adults (24/29 patients) had a significantly higher rate. A total of 35.9% of samples were positive for bacterial culture; Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, and Morganella morganii, while Bacteroides fragilis, Acinetobacter baumannii, Moraxella catarrhalis, and Escherichia coli were not identified by culture, although high cycle-threshold values were obtained suggesting the inability of the culture system in detecting some pathogens. CONCLUSION: Our results indicate that HIRA-TAN is a potential diagnostic tool in suppurative otitis media and warrant a larger cohort study

    Thermodynamic properties of a tetramer ferro-ferro-antiferro-antiferromagnetic Ising-Heisenberg bond alternating chain as a model system for Cu(3-Clpy)2_2(N3_3)2_2

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    Thermodynamic properties of a tetramer ferro-ferro-antiferro-antiferromagnetic Ising-Heisenberg bond alternating chain are investigated by the use of an exact mapping transformation technique. Exact results for the magnetization, susceptibility and specific heat in the zero as well as nonzero magnetic field are presented and discussed in detail. The results obtained from the mapping are compared with the relevant experimental data of Cu(3-Clpy)2_2(N3_3)2_2 (3-Clpy=3-Chloropyridine).Comment: 10 pages, 1 table, 14 figures, to be presented at CSMAG04 conferenc

    A rechargeable lithium metal battery operating at intermediate temperatures using molten alkali bis(trifluoromethylsulfonyl)amide mixture as an electrolyte

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    The physicochemical properties of molten alkali bis(trifluoromethylsulfonyl)amide, MTFSI (M = Li, K, Cs), mixture (xLiTFSI = 0.20, xKTFSI = 0.10, xCsTFSI = 0.70) were studied to develop a new rechargeable lithium battery operating at intermediate temperature (100–180 °C). The viscosity and ionic conductivity of this melt at 150 °C are 87.2 cP and 14.2 mS cm⁻¹, respectively. The cyclic voltammetry revealed that the electrochemical window at 150 °C is as wide as 5.0 V, and that the electrochemical deposition/dissolution of lithium metal occurs at the cathode limit. A Li/MTFSI (M = Li, K, Cs)/LiFePO₄ cell showed an excellent cycle performance at a constant current rate of C/10 at 150 °C; 95% of the initial discharge capacity was maintained after 50 cycles. Except for the initial few cycles, the coulombic efficiencies were approximately 100% for all the cycles, indicating the stabilities of the molten MTFSI mixture and all the electrode materials

    Recurrent pneumonia with mild hypogammaglobulinemia diagnosed as X-linked agammaglobulinemia in adults

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    <p>Abstract</p> <p>Background</p> <p>X-linked agammaglobulinemia (XLA) is a humoral immunodeficiency caused by disruption of the Bruton's tyrosine kinase (BTK) gene. Typical XLA patients suffer recurrent and severe bacterial infections in childhood.</p> <p>Methods</p> <p>Flow cytometric analysis of the peripheral monocytes using the anti-BTK antibody was used to characterize a 27 year old male patient with mild hypogammaglobulinemia (IgG, 635 mg/dl; IgM, 11 mg/dl; IgA, <5 mg/dl). He had suffered from frequent pneumonia since age 25 but had no history of frequent infections in his childhood or in adolescence. Sequencing of the BTK cDNA obtained from an Epstein–Barr virus-transformed B lymphoblastoid cell line derived from the bone marrow of the patient was performed to confirm a genetic defect.</p> <p>Results</p> <p>Flow cytometric analysis of cytoplasmic BTK protein in peripheral monocytes indicated that the patient presents a rare case of adult-onset XLA and that his mother is an XLA carrier. Sequencing of the BTK gene revealed a deletion of AG in the codon for Glu605 (AGT), resulting in an aberrant stop codon that truncates the BTK protein in its kinase domain.</p> <p>Conclusions</p> <p>This case suggests that some XLA cases may remain undiagnosed because they only show mild hypogammaglobulinemia and they lack repeated infections in childhood. Flow cytometric analysis is a powerful method to screen these patients.</p

    Supergravity at Colliders

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    We consider supersymmetric theories where the gravitino is the lightest superparticle (LSP). Assuming that the long-lived next-to-lightest superparticle (NSP) is a charged slepton, we investigate two complementary ways to prove the existence of supergravity in nature. The first is based on the NSP lifetime which in supergravity depends only on the Planck scale and the NSP and gravitino masses. With the gravitino mass inferred from kinematics, the measurement of the NSP lifetime will test an unequivocal prediction of supergravity. The second way makes use of the 3-body NSP decay. The angular and energy distributions and the polarizations of the final state photon and lepton carry the information on the spin of the gravitino and on its couplings to matter and radiation.Comment: 13 pages, 11 figures; v2: 3 references added, to appear in Physics Letters
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