372 research outputs found

    Phase singularity annihilation in plasmonic nano-apertures via epsilon-near-zero metamaterials

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    In this work, we performed an extensive theoretical and experimental study to unveil the underlying mechanisms related to the intensified transmittance in epsilon-near-zero (ENZ)-integrated plasmonic nano-apertures. The occurrence of phase singularities at the incident side of plasmonic nano-apertures results in the reduction in transmittance. We show that transmittance enhancement in ENZ-integrated nano-slits is attributed to the annihilation of the phase singularities by the ENZ layer and subsequently the modification in plasmonic fields of metallic apertures. The singularity annihilation via ENZ metamaterials eliminates the abrupt changes in the phase of the Poynting vector underneath the slit, which results in a stronger cavity resonance inside the aperture. Due to this fact, a nano-aperture on top of an ENZ metamaterial is the only effective configuration to enhance the transmittance in ENZ-integrated nano-apertures. Hence, our study reveals the physics of the transmittance enhancement through ENZ-integrated plasmonic nano-apertures.publishedVersionPeer reviewe

    Humoral immune consequences of Staphylococcus aureus ST239-associated bacteremia

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    The humoral immune responses against 46 different staphylococcal antigens in 27 bacteremia patients infected by clonally related methicillin-resistant Staphylococcus aureus (MRSA) strains of a single sequence type (ST) 239 were investigated. A group of non-infected patients (n = 31) hospitalized for different reasons served as controls. All strains were confirmed as ST 239 by S. aureus and mecA-specific PCR, spa, and multi-locus sequence typing (MLST). In each bacteremia patient, a unique pattern of S. aureus antigen-specific immune responses after infection was observed. Antibody levels among bacteremia patients were significantly higher than controls for HlgB (P = 0.001), LukD (P = 0.009), LukF (P = 0.0001), SEA (P = 0.0001), SEB (P = 0.011), SEC (P = 0.010), SEQ (P = 0.049), IsaA (P = 0.043), IsdA (P = 0.038), IsdH (P = 0.01), SdrD (P = 0.001), SdrE (P = 0.046), EsxA (P = 0.0001), and SA0104 (P = 0.0001). On the other hand, the antibody levels were significantly higher among controls for SSL3 (P = 0.009), SSL9 (P = 0.002), and SSL10 (P = 0.007) when the IgG level on the day of infection was compared with that measured on the day of admission. Diversity was observed in the immune response against the antigens. However, a set of antigens (IsaA, IsdA, IsdH, SdrD, and HlgB) triggered a similar type of immune response in different individuals. We suggest that these antigens could be considered when developing a multi-component (passive) vaccine. SEA and/or its specific antibodies seem to play a critical role during ST239 MRSA bacteremia and SEA-targeted therapy may be a strategy to be considered

    An Improved Under-Frequency Load Shedding Scheme in Distribution Networks with Distributed Generation

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    When a distribution network consisting of Distributed Generations (DGs) is disconnected from upstream network, the system may be exposed to severe power imbalance. In order to prevent the damage of power plants, frequency relays operate and remove DGs from the network. In contrast to traditional methods, the main objective in new methods is to keep DG units in service in the islanded distribution system. Under-Frequency Load Shedding (UFLS) is one of the most important protection systems, which is the last chance for avoiding a system blackout following severe disturbance. This paper dealt with an adaptive UFLS method and considered the priority of loads to be shed, depending on the intensity of event, and loads look up table built by Rate of Change of Frequency of Loads (ROCOFL) indices based on the frequency of centre of inertia (fCOI). Different loads were shed depending on the event type diagnosed by measuring the initial Rate of Change of Frequency (ROCOF) in the method. The proposed UFLS method can stabilize the frequency of the distribution system in islanding mode by shedding sufficient loads. The simulation results confirmed the advantages of the methods in comparison to other proposed algorithms

    In vitro antioxidant and anticancer activity of young Zingiber officinale against human breast carcinoma cell lines

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    <p>Abstract</p> <p>Background</p> <p>Ginger is one of the most important spice crops and traditionally has been used as medicinal plant in Bangladesh. The present work is aimed to find out antioxidant and anticancer activities of two Bangladeshi ginger varieties (Fulbaria and Syedpuri) at young age grown under ambient (400 μmol/mol) and elevated (800 μmol/mol) CO<sub>2 </sub>concentrations against two human breast cancer cell lines (MCF-7 and MDA-MB-231).</p> <p>Methods</p> <p>The effects of ginger on MCF-7 and MDA-MB-231 cell lines were determined using TBA (thiobarbituric acid) and MTT [3-(4,5-dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide] assays. Reversed-phase HPLC was used to assay flavonoids composition among Fulbaria and Syedpuri ginger varieties grown under increasing CO<sub>2 </sub>concentration from 400 to 800 μmol/mol.</p> <p>Results</p> <p>Antioxidant activities in both varieties found increased significantly (P ≤ 0.05) with increasing CO<sub>2 </sub>concentration from 400 to 800 μmol/mol. High antioxidant activities were observed in the rhizomes of Syedpuri grown under elevated CO<sub>2 </sub>concentration. The results showed that enriched ginger extract (rhizomes) exhibited the highest anticancer activity on MCF-7 cancer cells with IC<sub>50 </sub>values of 34.8 and 25.7 μg/ml for Fulbaria and Syedpuri respectively. IC<sub>50 </sub>values for MDA-MB-231 exhibition were 32.53 and 30.20 μg/ml for rhizomes extract of Fulbaria and Syedpuri accordingly.</p> <p>Conclusions</p> <p>Fulbaria and Syedpuri possess antioxidant and anticancer properties especially when grown under elevated CO<sub>2 </sub>concentration. The use of ginger grown under elevated CO<sub>2 </sub>concentration may have potential in the treatment and prevention of cancer.</p

    Methicillin-susceptible Staphylococcus aureus from clinical and community sources are genetically diverse.

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    Despite the association of methicillin-susceptible S. aureus (MSSA) with several life-threatening diseases, relatively little is known about their clinical epidemiology in Malaysia. We characterized MSSA isolates (n=252) obtained from clinical and community (carriage) sources based on spa sequencing and multilocus sequence typing (MLST). The prevalence of several important virulence genes was determined to further define the molecular characteristics of MSSA clones circulating in Malaysia. Among the 142 clinical and 110 community-acquired MSSA isolates, 98 different spa types were identified, corresponding to 8 different spa clonal clusters (spa-CCs). In addition, MLST analysis revealed 22 sequence types (STs) with 5 singletons corresponding to 12 MLST-CCs. Interestingly, spa-CC084/085 (MLST-CC15) (p=0.038), spa-non-founder 2 (MLST-ST188) (p=0.002), and spa-CC127 (MLST-CC1) (p=0.049) were identified significantly more often among clinical isolates. spa-CC3204 (MLST-CC121) (p=0.02) and spa-CC015 (MLST-CC45) (p=0.0002) were more common among community isolates. Five dominant MLST-CCs (CC8, CC121, CC1, CC45, and CC5) having clear counterparts among the major MRSA clones were also identified in this study. While the MSSA strains are usually genetically heterogeneous, a relatively high frequency (19/7.5%) of ST188 (t189) strains was found, with 57.8% of these strains carrying the Panton-Valentine leukocidin (PVL). Analysis of additional virulence genes showed a frequency of 36.5% and 36.9% for seg and sei and 0.8% and 6.3% for etb and tst genes, respectively. Arginine catabolic mobile element (ACME) was detected in 4 community isolates only. These represent the first isolates harbouring this gene in an Asian region. In conclusion, MSSA from the Malaysian community and their clinical counterparts are genetically diverse, but certain clones occur more often among clinical isolates than among carriage isolates and vice versa

    Understanding the relationship between pet owners and their companion animals as a key context for antimicrobial resistance-related behaviours: an Interpretative Phenomenological Analysis

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    Objectives: Drivers of antimicrobial resistance (AMR) are diffuse and complex including a range of interspecies behaviours between pet owners and their animals. We employed interpretative phenomenological analysis (IPA) to explore the relationship between pet owners and their companion animals in relation to AMR.Design: Cross sectional, qualitative study.Methods: Semi-structured interviews were conducted with twenty-three British pet owners, transcribed verbatim and subjected to Interpretative Phenomenological Analysis (IPA).Results: Three, inter-related Superordinate themes are presented 1) ‘They’re my fur babies’: unconditional love and anthropomorphism; 2) ‘They share everything with you’: affection and transmission behaviours; and 3) ‘We would err on the side of caution’: decision making and antibiotic use’.Conclusions: Affectionate behaviors between companion animals and their owners pose a risk for AMR transmission but they are so deeply treasured that they are unlikely to be amenable to change. In contrast, the promotion of appropriate antibiotic stewardship for pet owners and vets may offer a viable pathway for intervention development, benefitting from synergies with other interventions that target prescribers

    The Narrative Frame of Daniel: A Literary Assessment

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    This paper presents a fuzzy multicriteria group decision making approach for evaluating and selecting information systems projects. The inherent subjectiveness and imprecision of the evaluation process is modeled by using linguistic terms characterized by triangular fuzzy numbers. A new algorithm based on the concept of the degree of dominance is developed to avoid the complex and unreliable process of comparing fuzzy numbers usually required in fuzzy multicriteria decision making. A multicriteria decision support system is proposed to facilitate the evaluation and selection process. An information systems project selection problem is presented to demonstrate the effectiveness of the approach

    Livestock-associated MRSA colonization of occupational exposed workers and households in Europe: a review

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    The worldwide escalation in antibiotic resistant microorganisms has sustained the increasing concerns regarding antibiotics extensive use in animal food industry, which can result in a selection pressure that is driving the emergence of strains such as methicillin-resistant staphylococcus aureus (MRSA). Human MRSA infections are a well-known cause of numerous hospitalizations and deaths associated with extremely high mortality rates for invasive infections. Both animals and humans can become bacterial reservoirs of Livestock Associated MRSA (LA-MRSA) in which colonization predisposes to staphylococcal acquisition in clinical settings and to transfer the infection to others including household members. Biomonitoring of occupational exposed individuals which spend several hours per day in direct contact with MRSA-positive animals and thus are irrefutably exposed to a high risk of nasal colonization is imperative in order to develop effective preventive strategies. Here we performed an extensive review regarding the prevalence of LA- MRSA colonization in both occupational exposed individuals and their house-holds in a European context.info:eu-repo/semantics/publishedVersio

    Circulating Progenitor Cells Identify Peripheral Arterial Disease in Patients With Coronary Artery Disease

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    RATIONALE: Peripheral arterial disease (PAD) is a clinical manifestation of extracoronary atherosclerosis. Despite sharing the same risk factors, only 20% to 30% of patients with coronary artery disease (CAD) develop PAD. Decline in the number of bone marrow–derived circulating progenitor cells (PCs) is thought to contribute to the pathogenesis of atherosclerosis. Whether specific changes in PCs differentiate patients with both PAD and CAD from those with CAD alone is unknown. OBJECTIVE: Determine whether differences exist in PCs counts of CAD patients with and without known PAD. METHODS AND RESULTS: 1497 patients (mean age: 65 years; 62% men) with known CAD were identified in the Emory Cardiovascular Biobank. Presence of PAD (n=308) was determined by history, review of medical records, or imaging and was classified as carotid (53%), lower extremity (41%), upper extremity (3%), and aortic disease (33%). Circulating PCs were enumerated by flow cytometry. Patients with CAD and PAD had significantly lower PC counts compared with those with only CAD. In multivariable analysis, a 50% decrease in cluster of differentiation 34 (CD34+) or CD34+/vascular endothelial growth factor receptor-2 (VEGFR2+) counts was associated with a 31% (P=0.032) and 183% (P=0.002) increase in the odds of having PAD, respectively. CD34+ and CD34+/VEGFR2+ counts significantly improved risk prediction metrics for prevalent PAD. Low CD34+/VEGFR2+ counts were associated with a 1.40-fold (95% confidence interval, 1.03–1.91) and a 1.64-fold (95% confidence interval, 1.07–2.50) increases in the risk of mortality and PAD-related events, respectively. CONCLUSIONS: PAD is associated with low CD34+ and CD34+/VEGFR2+ PC counts. Whether low PC counts are useful in screening for PAD needs to be investigated
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