38 research outputs found

    The Sound of Topology in the AdS/CFT Correspondence

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    Using the gauge/gravity correspondence, we study the properties of 2-point correlation functions of finite-temperature strongly coupled gauge field theories, defined on a curved space of general spatial topology with a dual black hole description. We derive approximate asymptotic expressions for the correlation functions and their poles, supported by exact numerical calculations, and study their dependence on the dimension of spacetime and the spatial topology. The asymptotic structure of the correlation functions depends on the relation between the spatial curvature and the temperature, and is noticeable when they are of the same order. In the case of a hyperbolic topology, a specific temperature is identified for which exact analytical solutions exist for all types of perturbations. The asymptotic structure of the correlation functions poles is found to behave in a non-smooth manner when approaching this temperature.Comment: 65 pages, LaTeX, 21 figures, 1 table; fixed a small error in subsection 3.

    A scalar field instability of rotating and charged black holes in (4+1)-dimensional Anti-de Sitter space-time

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    We study the stability of static as well as of rotating and charged black holes in (4+1)-dimensional Anti-de Sitter space-time which possess spherical horizon topology. We observe a non-linear instability related to the condensation of a charged, tachyonic scalar field and construct "hairy" black hole solutions of the full system of coupled Einstein, Maxwell and scalar field equations. We observe that the limiting solution for small horizon radius is either a hairy soliton solution or a singular solution that is not a regular extremal solution. Within the context of the gauge/gravity duality the condensation of the scalar field describes a holographic conductor/superconductor phase transition on the surface of a sphere.Comment: 16 pages including 8 figures, v2: discussion on soliton solutions extended; v3: matches version accepted for publication in JHE

    New AdS solitons and brane worlds with compact extra-dimensions

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    We construct new static, asymptotically AdS solutions where the conformal infinity is the product of Minkowski spacetime MnM_n and a sphere SmS^m. Both globally regular, soliton-type solutions and black hole solutions are considered. The black holes can be viewed as natural AdS generalizations of the Schwarzschild black branes in Kaluza-Klein theory. The solitons provide new brane-world models with compact extra-dimensions. Different from the Randall-Sundrum single-brane scenario, a Schwarzschild black hole on the Ricci flat part of these branes does not lead to a naked singularity in the bulk.Comment: 28 pages, 4 figure

    Skin-impedance in Fabry Disease: A prospective, controlled, non-randomized clinical study

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    <p>Abstract</p> <p>Background</p> <p>We previously demonstrated improved sweating after enzyme replacement therapy (ERT) in Fabry disease using the thermo-regularity sweat and quantitative sudomotor axon reflex tests. Skin-impedance, a measure skin-moisture (sweating), has been used in the clinical evaluation of burns and pressure ulcers using the portable dynamic dermal impedance monitor (DDIM) system.</p> <p>Methods</p> <p>We compared skin impedance measurements in hemizygous patients with Fabry disease (22 post 3-years of bi-weekly ERT and 5 ERT naive) and 22 healthy controls. Force compensated skin-moisture values were used for statistical analysis. Outcome measures included 1) moisture reading of the 100<sup>th </sup>repetitive reading, 2) rate of change, 3) average of 60–110<sup>th </sup>reading and 4) overall average of all readings.</p> <p>Results</p> <p>All outcome measures showed a significant difference in skin-moisture between Fabry patients and control subjects (p < 0.0001). There was no difference between Fabry patients on ERT and patients naïve to ERT. Increased skin-impedance values for the four skin-impedance outcome measures were found in a small number of dermatome test-sites two days post-enzyme infusions.</p> <p>Conclusion</p> <p>The instrument portability, ease of its use, a relatively short time required for the assessment, and the fact that DDIM system was able to detect the difference in skin-moisture renders the instrument a useful clinical tool.</p

    Selective Alpha-Particle Mediated Depletion of Tumor Vasculature with Vascular Normalization

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    BACKGROUND: Abnormal regulation of angiogenesis in tumors results in the formation of vessels that are necessary for tumor growth, but compromised in structure and function. Abnormal tumor vasculature impairs oxygen and drug delivery and results in radiotherapy and chemotherapy resistance, respectively. Alpha particles are extraordinarily potent, short-ranged radiations with geometry uniquely suitable for selectively killing neovasculature. METHODOLOGY AND PRINCIPAL FINDINGS: Actinium-225 ((225)Ac)-E4G10, an alpha-emitting antibody construct reactive with the unengaged form of vascular endothelial cadherin, is capable of potent, selective killing of tumor neovascular endothelium and late endothelial progenitors in bone-marrow and blood. No specific normal-tissue uptake of E4G10 was seen by imaging or post-mortem biodistribution studies in mice. In a mouse-model of prostatic carcinoma, (225)Ac-E4G10 treatment resulted in inhibition of tumor growth, lower serum prostate specific antigen level and markedly prolonged survival, which was further enhanced by subsequent administration of paclitaxel. Immunohistochemistry revealed lower vessel density and enhanced tumor cell apoptosis in (225)Ac-E4G10 treated tumors. Additionally, the residual tumor vasculature appeared normalized as evident by enhanced pericyte coverage following (225)Ac-E4G10 therapy. However, no toxicity was observed in vascularized normal organs following (225)Ac-E4G10 therapy. CONCLUSIONS: The data suggest that alpha-particle immunotherapy to neovasculature, alone or in combination with sequential chemotherapy, is an effective approach to cancer therapy

    Overhead tank is the potential breeding habitat of Anopheles stephensi in an urban transmission setting of Chennai, India

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    Background: Wells and overhead tanks (OHT) are the major breeding sources of the local malaria vector, Anopheles stephensi in the Indian city of Chennai; they play a significant role in vector breeding, and transmission of urban malaria. Many other man-made breeding habitats, such as cemented cisterns/containers, barrels or drums, sumps or underground tanks, and plastic pots/containers are maintained to supplement water needs, temporarily resulting in enhanced mosquito/vector breeding. Correlating breeding habitats with immature vector abundance is important in effective planning to strengthen operational execution of vector control measures. Methods: A year-long, weekly study was conducted in Chennai to inspect available clear/clean water mosquito breeding habitats. Different breeding features, such as instar-wise, immature density and co-inhabitation with other mosquito species, were analysed. The characteristics of breeding habitats, i.e., type of habitat, water temperature and presence of aquatic organisms, organic matter and green algal remnants on the water surface at the time of inspection, were also studied. Immature density of vector was correlated with presence of other mosquito species, malaria prevalence, habitat characteristics and monthly/seasonal fluctuations. All the data collected from field observations were analysed using standard statistical tools. Results: When the immature density of breeding habitats was analysed, using one-way ANOVA, it was observed that the density did not change in a significant way either across seasons or months. OHTs contributed significantly to the immature population when compared to wells and other breeding habitats of the study site. The habitat positivity of wells and OHTs was significantly associated with the presence of aquatic organisms, organic matter and algal remnants. Significant correlations of malaria prevalence with monthly immature density, as well as number of breeding habitats with immature vector mosquitoes, were also observed. Conclusions: The findings that OHTs showed fairly high and consistent immature density of An. stephensi irrespective of seasons indicates the potentiality of the breeding habitat in contributing to vector density. The correlation between vector breeding habitats, immature density and malaria prevalence indicates the proximity of these habitats to malaria cases, proving its role in vector abundance and local malaria transmission. The preference of An. stephensi to breed in OHTs calls for intensified, appropriate and sustained intervention measures to curtail vector breeding and propagation to shrink malaria to pre-elimination level and beyond

    OFET based explosive sensors using diketopyrrolopyrrole and metal organic framework composite active channel material

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    Detection of explosives using organic compounds poses many challenges, primarily because of the stability of the organic compound at nominal operating conditions. This paper addresses the aforementioned challenge by reporting a new organic material composite, whose stability is suitable for practical applications. Additionally, the reported organic composite is also capable of detecting vapors of Nitro based explosive compounds such as 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX). An alternating copolymer of thiophene flanked diketopyrrolopyrrole with thienylene-vinylenethienylene (PDPP-TVT) was used as a solution processable and spin coatable organic semiconductor active channel material for the organic field effect transistor (OFET) sensor. A composite of PDPP-TVT and metal organic framework (MOF) was used as a receptor and pre-concentrator sites for sensing of the explosive analytes. The sensor devices were characterized and the receptor sites were confirmed by the Fourier Transform Infrared Spectroscopy (FTIR) and atomic force microscopy (AFM). The detection of viable analytes is recognized by the percentage change in the saturated drain current (%Delta I-Dsat) obtained by the current (I)-voltage ( V) characteristics with and without the analyte. The corresponding %Delta I-Dsat recorded for nitrobenzene (NB), dinitrobenzene (DNB), nitromethane (NM), TNT and RDX are -7%, 2%, 24%, 81% and 50%, respectively. (C) 2015 Elsevier B.V. All rights reserved

    Unusual cause of generalized osteolytic vertebral lesions: a case report

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    <p>Abstract</p> <p>Background</p> <p>Vertebral sarcoidosis is an extremely rare form of osseous sarcoidosis. Although osseous sarcoidosis is almost always an incidental finding of sarcoidosis elsewhere in the body, vertebrae may be the primary disease site. Involvement of vertebrae is usually localized and sclerotic or lytic.</p> <p>Case presentation</p> <p>We describe a case of extensive asymptomatic vertebral involvement by sarcoid with osteolytic lesions. Making the diagnosis requires biopsy and ruling out other commoner causes of osteolytic vertebral lesions.</p> <p>Conclusion</p> <p>We report this case in the hope of expanding the knowledge of osseous sarcoidosis. Our patient was unique in that all involvement was axial with sparing of the peripheral skeleton, near absence of any other organ involvement, diffuse involvement of the whole spine and osteolytic bone lesions.</p
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