1,041 research outputs found

    WZNW Models from Non-Standard Bilinear Forms

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    We study the WZNW models based on nonstandard bilinear forms. We approach the problem from algebraic, perturbative and functional exact methods. It is shown that even in the case of integer kk we can find irrational CFT's. We prove that when the base group is noncompact with nonabelian maximal compact subgroup, the Kac-Moody representations are nonunitary.Comment: LaTeX file, 26 page

    Think Twice before Prescribing Antibiotics for That Swollen Knee: The Influence of Antibiotics on the Diagnosis of Periprosthetic Joint Infection.

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    Periprosthetic joint infection (PJI) is a rare but devastating complication after total joint arthroplasty. An estimated 7-12% of patients have negative cultures despite clear clinical evidence of infection. One oft-cited reason for this occurrence is the administration of antibiotics in the weeks prior to obtaining cultures. This article reviews the influence of antibiotics on the diagnosis of PJI. Specifically, we examine the effect of prophylactic and therapeutic antibiotic administration on the diagnostic accuracy of microbiological cultures as well as serum and synovial biomarkers. We also explore the potential of molecular techniques in overcoming these limitations in patients who have received antibiotics before specimen collection and propose areas for future research

    Natural source-based graphene as sensitising agents for air quality monitoring

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    Natural carbon powder has been used as a precursor to prepare two main types of sensitising agents of nitrogen-doped carbon nanoparticles (N-CNPs) and nitrogen-doped graphene quantum dots coupled to nanosheets (N-GQDs-NSs) by using simple treatments of chemical oxidation and centrifugation separation. Characterization based on FTIR, XPS, XRD, Raman spectroscopy, FE-SEM, HR-TEM, AFM, UV-Vis and FL, revealed successful doping carbon nanoparticle with nitrogen with an average plane dimension of 50 nm and relatively smooth surface. The versatility of the prepared samples as sensitising agents was developed and established by exploiting its ability for detection of volatile organic compounds via simple optical fibre based sensing configuration. The comparative experimental studies on the proposed sensor performance indicate fast response achieved at a few tens of seconds and excellent repeatability in exposure to the methanol vapour. The low limit of detection of 4.3, 4.9 and 10.5 ppm was obtained in exposure to the methanol, ethanol and propanol vapours, respectively, in the atmosphere condition. This study gives insights into the chemical/physical mechanism of an enhanced economic optical fibre based gas sensor and illustrates it for diverse sensing applications, especially for chemical vapour remote detection and future air quality monitoring

    Nanotechnology: current concepts in orthopaedic surgery and future directions.

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    Nanotechnology is the study, production and controlled manipulation of materials with a grain size \u3c 100 nm. At this level, the laws of classical mechanics fall away and those of quantum mechanics take over, resulting in unique behaviour of matter in terms of melting point, conductivity and reactivity. Additionally, and likely more significant, as grain size decreases, the ratio of surface area to volume drastically increases, allowing for greater interaction between implants and the surrounding cellular environment. This favourable increase in surface area plays an important role in mesenchymal cell differentiation and ultimately bone-implant interactions. Basic science and translational research have revealed important potential applications for nanotechnology in orthopaedic surgery, particularly with regard to improving the interaction between implants and host bone. Nanophase materials more closely match the architecture of native trabecular bone, thereby greatly improving the osseo-integration of orthopaedic implants. Nanophase-coated prostheses can also reduce bacterial adhesion more than conventionally surfaced prostheses. Nanophase selenium has shown great promise when used for tumour reconstructions, as has nanophase silver in the management of traumatic wounds. Nanophase silver may significantly improve healing of peripheral nerve injuries, and nanophase gold has powerful anti-inflammatory effects on tendon inflammation. Considerable advances must be made in our understanding of the potential health risks of production, implantation and wear patterns of nanophase devices before they are approved for clinical use. Their potential, however, is considerable, and is likely to benefit us all in the future. Cite this article: Bone Joint J 2014; 96-B: 569-73

    Adolescents' view of health concept and its risk factors: A literature review

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    Background: Adolescence is the important period in human life. It is an essential prerequisite for playing social roles. Objective: The current study conducted a review on the concept, dimensions, and influential factors on health and risk taking, instruments and measurements of high-risk behaviors, risk factors, and high-risk behavior protective factors through adolescent perspectives. Methods: This literature review was conducted by electronic searching and library study on health and adolescents using Wiley Interscience, ScienceDirect, ProQuest, and Springer (1990-2012). The keywords for searching data collection sources included health, youth, young, adolescents, risk behaviors, risk taking, related factors, protective factors, risk factors, adolescent perspectives, quantitative study, qualitative study, measurement, and instrument. Results: This literature review led to the arrangement of subjects in nine general categories titled definition of health concept and its dimensions, adolescents and health in adolescence, risk taking in adolescence and its measuring tools, gender differences in adolescence health and risk taking, adolescents' health and relationships, socioeconomic conditions and health, adolescents and psychiatric health, religion, and health, educational facilities and health, non-governmental organizations and their role in adolescents' health. What has been achieved from a review of these articles is that several personal, social, and family factors are associated with health and risk taking in adolescents. Conclusion: Generally, adolescents cared more about the psychosocial aspects of health than the physical dimensions. They also considered factors such as independence, communication, socioeconomic conditions, mental health, religion, and educational facilities synonymous with the concept of health. Therefore, in formulation and implementation of health promotion programs for adolescents, the concept of health and its various dimensions must be considered from adolescent perspectives. © 2014 by De Gruyter 2014

    New Attractors, Entropy Function and Black Hole Partition Function

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    By making use of the entropy function formalism we study the generalized attractor equations in the four dimensional N=2 supergravity in presence of higher order corrections. This result might be used to understand a possible ensemble one could associate to an extremal black hole.Comment: 20 pages, latex file, V2: minor corrections, typos corrected, Refs added, V3: the version appeared in JHE

    Periprosthetic joint infection: are patients with multiple prosthetic joints at risk?

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    Patients who present with a periprosthetic joint infection in a single joint may have multiple prosthetic joints. The risk of these patients developing a subsequent infection in another prosthetic joint is unknown. Our purposes were (1) to identify the risk of developing a subsequent infection in another prosthetic joint and (2) to describe the time span and organism profile to the second prosthetic infection. We retrospectively identified 55 patients with periprosthetic joint infection who had another prosthetic joint in place at the time of presentation. Of the 55 patients, 11 (20%) developed a periprosthetic joint infection in a second joint. The type of organism was the same as the first infection in 4 (36%) of 11 patients. The time to developing a second infection averaged 2.0 years (range, 0-6.9 years)
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