370 research outputs found

    Prefect Transfer of Quantum States on Spin Chain with Dzyaloshinskii- Moriya interaction in inhomogeneous Magnetic field

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    In this work, we use the Hamiltonian of a modified Dzyaloshinskii-Moriya model and investigate the perfect transfer of the quantum state on the spin networks. In this paper, we calculate fidelity in which fidelity depends on magnetic field and another parameters. Then, by using the numerical analysis we show that the fidelity of the transferred state is determined by magnetic field BB, exchange coupling JJ and the Dzyaloshinskii- Moriya interaction DD. We also found that the perfect transfer of the quantum state is possible with condition BΓ2ωN/2B \gg \Gamma^2\omega^{N/2} where Γ=((J+iD)/2)\Gamma =((J+iD)/2) and ω=Γ/Γ\omega=\Gamma^*/ \Gamma.Comment: 8 pages, 2 figure

    Free space operating microwave imaging device for bone lesion detection: a phantom investigation

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    In this letter, a phantom validation of a low complexity microwave imaging device operating in free space in the 1-6.5 GHz frequency band is presented. The device, initially constructed for breast cancer detection, measures the scattered signals in a multi-bistatic fashion and employs an imaging procedure based on Huygens principle. Detection has been achieved in both bone fracture lesion and bone marrow lesion scenarios using the superimposition of five doublet transmitting positions, after applying the rotation subtraction artefact removal method. A resolution of 5 mm and a signal to clutter ratio (3.35 in linear scale) are achieved confirming the advantage of employing multiple transmitting positions on increased detection capability

    3D Huygens Principle based Microwave Imaging through MammoWave Device: Validation through Phantoms.

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    This work focuses on developing a 3D microwave imaging (MWI) algorithm based on the Huygens principle (HP). Specifically, a novel, fast MWI device (MammoWave) has been presented and exploited for its capabilities of extending image reconstruction from 2D to 3D. For this purpose, dedicated phantoms containing 3D structured inclusion have been prepared with mixtures having different dielectric properties. Phantom measurements have been performed at multiple planes along the z-axis by simultaneously changing the transmitter and receiver antenna height via the graphic user interface (GUI) integrated with MammoWave. We have recorded the complex S21 multi-quote data at multiple planes along the z-axis. The complex multidimensional raw data has been processed via an enhanced HP-based image algorithm for 3D image reconstruction. This paper demonstrates the successful detection and 3D visualization of the inclusion with varying dimensions at multiple planes/cross-sections along the z-axis with a dimensional error lower than 7.5%. Moreover, the paper shows successful detection and 3D visualization of the inclusion in a skull-mimicking phantom having a cylindrically shaped inclusion, with the location of the detected inclusion in agreement with the experimental setup. Additionally, the localization of a 3D structured spherical inclusion has been shown in a more complex scenario using a 3-layer cylindrically shaped phantom, along with the corresponding 3D image reconstruction and visualization

    UWB Microwave Imaging for Inclusions Detection: Methodology for Comparing Artefact Removal Algorithms

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    An investigation is presented on Artefact Removal Methods for Ultra-Wideband (UWB) Microwave Imaging. Simulations have been done representing UWB signals transmitted onto a cylindrical head-mimicking phantom containing an inclusion having dielectric properties imitating an haemorrhagic stroke. The ideal image is constructed by applying a Huygens’ Principle based imaging algorithm to the difference between the electric field outside the cylinder with an inclusion and the electric field outside the same cylinder with no inclusion. Eight different artefact removal methods are then applied, with the inclusion positioned at \u1d70b and −\u1d70b/4 radians, respectively. The ideal image is then used as a reference image to compare the artefact removal methods employing a novel Image Quality Index, calculated using a weighted combination of image quality metrics. The Summed Symmetric Differential method performed very well in our simulations

    Microwave imaging for stroke detection: validation on head-mimicking phantom

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    This paper provides initial results on the efficacy of Huygens Principle (HP) microwave imaging for haemorrhagic stroke detection. This is done using both simulations and measurements in an anechoic chamber. Microstrip antennas operating between 1 and 2 GHz have been designed, constructed and used for imaging a human head model in Computer Simulation Technology (CST) software. A 3D model consisting of human head tissues of Ella is employed in the simulation. An emulated haemorrhagic stroke with the dielectric properties equivalent to the blood has been inserted in Ella. Moreover, a 3-layered head-mimicking phantom containing an inclusion has been constructed. Frequency-domain measurements have been performed in an anechoic chamber using a Vector Network Analyser arrangement to obtain the transfer function (S21) between two antennas. Both simulations and measurements show that the HP based technique may be used for haemorrhagic stroke detection. Among linear scattering techniques, the HP based technique allows to detect dielectric inhomogeneities in the frequency domain. HP can also be used if the antennas and phantom are in free space, i.e. no coupling liquid is required. Detection of the haemorrhagic stroke has been achieved after removing the artefacts. Artefact removal is an essential step of any microwave imaging system and current artefact removal approaches have been shown to be ineffective in the specific scenario of brain imaging. However, one of this paper’s novel contributions is the proposal of an artefact removal algorithm based on a subtraction between S21 obtained using measurements, which achieves improved performance while having a much lower computational complexity

    Educational case: Pseudomonas and acinetobacter sepsis due to thermal injury

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    Background: Multi drug resistant (MDR) Pseudomonas and Acinetobacter species are defined as resistant to at least three classes of antibiotics. Most studies have demonstrated that MDR gram negative infections convey increased mortality and morbidity. Case: An 11-year âold girl was admitted to pediatric burns unit with burn injury of approximately 68 total body surface area (TBSA). Discussion: Role of systemic antibiotics is adjunctive and never replaces surgical debridement, use of topical agents, nutritional support, increasing in immune system function and grafting. Evidence in the published literature suggests that combination therapy with Meropenem and Colistin are effective for burned patients with MDR gram negative sepsis. © 2013, Kowsar Corp

    Prevalence of beta lactamase producing species of pseudomonas and acinetobacter in pediatric burn patients Prevalence de pseudomonas et acinetobacter secreteurs de blse et metallo-beta lactamases chez les brules pediatriques

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    Burn wound infection is a major cause of morbidity and mortality in burn victims. Pseudomonas and Acinetobacter species are among the most common organisms complicating burn wounds. Presence of extended spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) genes plays an important role in spreading β-lactam resistant strains of these organisms and is a serious condition in the treatment of the affected patients. As a result, we aimed to determine the prevalence of SHV, TEM, PER and VIM β-lactamases in Pseudomonas and Acinetobacter species isolates from burn wound swabs of children with burn injury. In this descriptive observational study, 107 Pseudomonas and Acinetobacter isolates collected from burn patients were subjected to PCR assay. Using PCR method and DNA sequencing, the existence of SHV-, TEM-, PER- and VIM-type β-lactamase encoding genes were determined. Out of the 107 Pseudomonas and Acinetobacter isolates, 66 (77.6) were ESBL positive, 26.2 were positive for SHV gene, 37.4 were positive for TEM gene, 14 were positive for PER gene and 15.9 of them harbored VIM gene. More than half of the Pseudomonas and Acinetobacter strains in our pediatric burn unit harbor β-lactamase encoding genes that make them resistant to a wide range of β-lactam antibiotics. Consequently, it is suggested to choose an appropriate antibiotic regimen based on the antibiogram pattern of the strains. © 2015, Mediterranean Club for Burns and Fire Disasters. All rights reserved

    A user-centric system architecture for residential energy consumption reduction

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    Long-term energy consumption reduction can be achieved more readily through sensible cooperation between end users and technological advancements. The DANCER project presented here proposes a user-centric residential energy management system, with the intention to achieve long-term energy related behavioural changes, thus improving the energy efficiency of modern homes. Although, it follows the same basic principles as other contemporary approaches, it focuses on minimizing the interaction of the user with the system. This is achieved through an improved feedback mechanism and a generic, policy based service that takes advantage of the modularity and generality of the software architecture. The proposed system is designed to support a variety of technologies (WiFi, Zigbee, X10), in order to ameliorate the input and output of the decision making operation. In this paper, the general outline of the DANCER system architecture and its most important components are discussed and the prototype test-bed is presented. Special consideration is given to the implementation, operation and response behaviour of the prototype

    Immunomodulation and Generation of Tolerogenic Dendritic Cells by Probiotic Bacteria in Patients with Inflammatory Bowel Disease

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    In inflammatory bowel diseases (IBD), the therapeutic benefit and mucosal healing from specific probiotics may relate to the modulation of dendritic cells (DCs). Herein, we assessed the immunomodulatory effects of four probiotic strains including Lactobacillus salivarius, Bifidobacterium bifidum, Bacillus coagulans and Bacillus subtilis natto on the expression of co-stimulatory molecules, cytokine production and gene expression of signal-transducing receptors in DCs from IBD patients. Human monocyte-derived DCs from IBD patients and healthy controls were exposed to four probiotic strains. The expression of co-stimulatory molecules was assessed and supernatants were analyzed for anti-inflammatory cytokines. The gene expression of toll-like receptors (TLRs), IL-12p40 and integrin \u3b1v\u3b28 were also analyzed. CD80 and CD86 were induced by most probiotic strains in ulcerative colitis (UC) patients whereas only B. bifidum induced CD80 and CD86 expression in Crohn's disease (CD) patients. IL-10 and TGF-\u3b2 production was increased in a dose-independent manner while TLR expression was decreased by all probiotic bacteria except B. bifidum in DCs from UC patients. TLR-4 and TLR-9 expression was significantly downregulated while integrin f8 was significantly increased in the DCs from CD patients. IL-12p40 expression was only significantly downregulated in DCs from CD patients. Our findings point to the general beneficial effects of probiotics in DC immunomodulation and indicate that probiotic bacteria favorably modulate the expression of co-stimulatory molecules, proinflammatory cytokines and TLRs in DCs from IBD patients

    Serum 25-hydroxyvitamin D levels in pediatric burn patients

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    Background: Previous studies have implicated the important and active role of vitamin D in the immune system. Objectives: The aim of this study was to evaluate serum levels of 25-hydroxyvitamin D in children with burn injuries. Materials and Methods: In this cross-sectional study, 118 patients with various degrees of burn injuries were enrolled. A checklist consisting of demographic data, total body surface area (TBSA) affected by burn, degree of burn, serum level of 25(OH)D, total protein, albumin, electrolytes, and parathyroid hormone was recorded for each patient. Results: Sixty-eight (57.6) males and 50 (42.4) females with a mean age of 4.04 years (SD = 3.04) were evaluated. The mean level of 25(OH)D was 14.58 ng/mL (SD = 6.94). Levels of 25(OH)D in four (3.39) cases were higher than 30 ng/mL, while 95 (81.35) cases had levels lower than 20 ng/mL, and 19 (16.10) cases had levels of 21 - 30 ng/mL. The level of 25(OH)D was below recommended levels in 96.61 of cases, while 81.34 had vitamin D deficiency and 16.1 had insufficiency. We found a significant correlation between vitamin 25(OH)D and total protein, albumin, and total and ionized calcium (P < 0.001). There was also a significant negative correlation between 25(OH)D and TBSA affected by burn (P = 0.001). Conclusions: The levels of 25(OH)D in children suffering from severe burns were low. Supplementation might be useful in patients with very low levels of serum vitamin D. Copyright © 2016, Trauma Monthly
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