153 research outputs found

    Josephson glass and decoupling of flux lattices in layered superconductors

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    Phase transitions of a flux lattice in layered superconductors with magnetic field perpendicular to the layers and in presence of disorder are studied. We find that the Josephson coupling between layers leads to a strongly pinned Josephson glass (JG) phase at low temperatures and fields. The JG phase undergoes either a decoupling transition with increasing field or a depinning transition with increasing temperature. The resulting phases undergo further depinning and decoupling transitions, respectively, resulting in a phase diagram with a multicritical point where four phases meet. The phase diagram accounts for unusual data on Bi_2Sr_2CaCu_2O_8 such as the "second peak" transition and the recently observed depinning transitions.Comment: 5 pages, 1 eps figure, Revtex, Phys. Rev. Lett. (submitted

    Decoupling Transition I. Flux Lattices in Pure Layered Superconductors

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    We study the decoupling transition of flux lattices in a layered superconductors at which the Josephson coupling J is renormalized to zero. We identify the order parameter and related correlations; the latter are shown to decay as a power law in the decoupled phase. Within 2nd order renormalization group we find that the transition is always continuous, in contrast with results of the self consistent harmonic approximation. The critical temperature for weak J is ~1/B, where B is the magnetic field, while for strong J it is~1/sqrt{B} and is strongly enhanced. We show that renormaliztion group can be used to evaluate the Josephson plasma frequency and find that for weak J it is~1/BT^2 in the decoupled phase.Comment: 14 pages, 5 figures. New sections III, V. Companion to following article on "Decoupling and Depinning II: Flux lattices in disordered layered superconductors

    Anharmonicity of flux lattices and thermal fluctuations in layered superconductors

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    We study elasticity of a perpendicular flux lattice in a layered superconductor with Josephson coupling between layers. We find that the energy contains ln(flux displacement) terms, so that elastic constants cannot be strictly defined. Instead we define effective elastic constants by a thermal average. The tilt modulus has terms with ln(T) which for weak fields, i.e. Josephson length smaller than the flux line spacing, lead to displacement square average proportional to T/ln(T). The expansion parameter indicates that the dominant low temperature phase transition is either layer decoupling at high fields or melting at low fields.Comment: 15 pages, 2 eps figures, Revtex, submitted to Phys. Rev. B. Sunj-class: superconductivit

    Monoclonal gammopathy of undetermined significance and risk of lymphoid and myeloid malignancies: 728 cases followed up to 30 years in Sweden.

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    To access publisher's full text version of this article. Please click on the hyperlink in Additional Links field.In 728 Swedish cases of monoclonal gammopathy of undetermined significance (MGUS), followed up to 30 years (median, 10 years), we estimated the cumulative risk of hematologic disorders originating from lymphoid and myeloid lineages. Using Cox regression models, we examined associations of demographic and laboratory factors with progression and determined the discriminatory power of 3 prediction models for progression. Eighty-four MGUS cases developed a lymphoid disorder, representing a cumulative risk of 15.4%. Multiple myeloma (MM) occurred in 53 patients, and the 30-year cumulative risk was 10.6%; an ∼0.5% annual risk. Three factors were significantly associated with progression: abnormal free light-chain (FLC) ratio (1.65), M-protein concentration (≥1.5 g/dL), and reduction of 1 or 2 noninvolved immunoglobulin isotype levels (immunoparesis). A prediction model with separate effects for these 3 factors and the M-protein isotype had higher discriminatory power than other models, although the differences were not statistically significant. The 30-year cumulative risk for myeloid malignancies was 1.5 g/dL, factors previously considered by Mayo Clinic researchers, are predictors for MM progression and suggests that separate consideration of immunoparesis and the Mayo Clinic risk factors could improve identification of MGUS patients at high risk for progression

    Monoclonal gammopathy of undetermined significance and risk of infections: a population-based study.

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links field.No comprehensive evaluation has been made to assess the risk of viral and bacterial infections among patients with monoclonal gammopathy of undetermined significance. Using population-based data from Sweden, we estimated risk of infections among 5,326 monoclonal gammopathy of undetermined significance patients compared to 20,161 matched controls. Patients with monoclonal gammopathy of undetermined significance had a 2-fold increased risk (P<0.05) of developing any infection at 5- and 10-year follow up. More specifically, patients with monoclonal gammopathy of undetermined significance had an increased risk (P<0.05) of bacterial (pneumonia, osteomyelitis, septicemia, pyelonephritis, cellulitis, endocarditis, and meningitis), and viral (influenza and herpes zoster) infections. Patients with monoclonal gammopathy of undetermined significance with M-protein concentrations over 2.5 g/dL at diagnosis had highest risks of infections. However, the risk was also increased (P<0.05) among those with concentrations below 0.5 g/dL. Patients with monoclonal gammopathy of undetermined significance who developed infections had no excess risk of developing multiple myeloma, Waldenström macroglobulinemia or related malignancy. Our findings provide novel insights into the mechanisms behind infections in patients with plasma cell dyscrasias, and may have clinical implications.Stockholm County Council Karolinska Institutet Cancer Society in Stockholm NIH, NC

    Effect of melatonin on the retinal glutamate/glutamine cycle in the golden hamster retina

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    Glutamate is the main excitatory neurotransmitter in the retina, but it is neurotoxic when present in excessive amounts. The metabolic dependence of glutamatergic neurons upon glia via the glutamate/glutamine cycle to provide the precursor for neurotransmitter glutamate is well established. Since melatonin has been shown to be neuroprotective in several systems, in the present report, its effect on the glutamate/glutamine cycle activity was examined in the golden hamster retina. Melatonin (0.1−10 nM) significantly increased retinal glutamine synthetase activity but it did not affect L-glutamine release. A characterization of the hamster retinal Lglutamine uptake mechanism was performed. This mechanism was partly Na+ -dependent, and it was significantly inhibited by 2-aminobicyclo (2, 2, 1) heptane 2-carboxylic acid (BCH, a selective antagonists for the L-type system) and by α-(methylamino)-isobutyric acid (MeAIB, substrate characteristic for the A -type transporter) suggesting the coexistence of these transport systems in the hamster retina. Melatonin (0.1−10 nM) significantly increased total glutamine uptake as well as the BCH and the MeAIB-insensitive transporters activity. On the other hand, melatonin significantly decreased retinal glutaminase activity. On the basis of these results, it might be presumed that hamster retinal glutamate/glutamine cycle activity is regulated by physiological concentrations of melatonin. Furthermore, these findings suggest that a treatment with melatonin could be considered as a new approach to handling glutamate-mediated neuronal degeneration.Fil: Saenz, Daniel Alberto. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Goldin, Andrea Paula. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Minces, Luciana. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Chianelli, Mónica Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Keller Sarmiento, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: Rosenstein, Ruth Estela. Universidad de Buenos Aires. Facultad de Medicina; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

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    Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

    Mutant Ras and inflammation-driven skin tumorigenesis is suppressed via a JNK-iASPP-AP1 axis

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    Concurrent mutation of a RAS oncogene and the tumor suppressor p53 is common in tumorigenesis, and inflammation can promote RAS-driven tumorigenesis without the need to mutate p53. Here, we show, using a well-established mutant RAS and an inflammation-driven mouse skin tumor model, that loss of the p53 inhibitor iASPP facilitates tumorigenesis. Specifically, iASPP regulates expression of a subset of p63 and AP1 targets, including genes involved in skin differentiation and inflammation, suggesting that loss of iASPP in keratinocytes supports a tumor-promoting inflammatory microenvironment. Mechanistically, JNK-mediated phosphorylation regulates iASPP function and inhibits iASPP binding with AP1 components, such as JUND, via PXXP/SH3 domain-mediated interaction. Our results uncover a JNK-iASPP-AP1 regulatory axis that is crucial for tissue homeostasis. We show that iASPP is a tumor suppressor and an AP1 coregulator

    Brief of Tax Law Professors as \u3ci\u3eAmici Curiae\u3c/i\u3e in Support of Petitioner in \u3ci\u3eLoudoun County, Virginia v. Dulles Duty Free, LLC\u3c/i\u3e

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    Amici are professors of tax law at universities across the United States. As scholars and teachers, they have considered the doctrinal roots and practical consequences of judicial limits on state and local taxation. Amici join this brief solely on their own behalf and not as representatives of their universities. A full list of amici appears in the Appendix to this brief
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