2,271 research outputs found

    Boosted Top Quark Signals for Heavy Vector Boson Excitations in a Universal Extra Dimension Model

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    In view of the fact that the n=1n = 1 Kaluza-Klein (KK) modes in a model with a Universal Extra Dimension (UED), could mimic supersymmetry signatures at the LHC, it is necessary to look for the n=2n = 2 KK modes, which have no analogues in supersymmetry. We discuss the possibility of searching for heavy n=2n = 2 vector boson resonances -- especially the g2g_2 -- through their decays to a highly-boosted top quark-antiquark pair using recently-developed top-jet tagging techniques in the hadronic channel. It is shown that ttˉt\bar{t} signals from the n=2n = 2 gluon resonance are as efficient a discovery mode at the LHC as dilepton channels from the γ2\gamma_2 and Z2Z_2 resonances.Comment: 22 pages, 8 embedded figure

    Corrosion of bio implants

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    Chemical stability, mechanical behaviour and biocompatibility in body fluids and tissues are the basic requirements for successful application of implant materials in bone fractures and replacements. Corrosion is one of the major processes affecting the life and service of orthopaedic devices made of metals and alloys used as implants in the body. Among the metals and alloys known, stainless steels (SS), Co-Cr alloys and titanium and its alloys are the most widely used for the making of biodevices for extended life in human body. Incidences of failure of stainless steel implant devices reveal the occurrence of significant localised corroding viz., pitting and crevice corrosion. Titanium forms a stable TiO2 film which can release titanium particles under wear into the body environment. To reduce corrosion and achieve better biocompatibility, bulk alloying of stainless steels with titanium and nitrogen, surface alloying by ion implantation of stainless steels and titanium and its alloys, and surface modification of stainless steel with bioceramic coatings are considered potential methods for improving the performance of orthopaedic devices. This review discusses these issues in depth and examines emerging directions

    Formulation and characterization of an apigenin-phospholipid phytosome (APLC) for improved solubility, in vivo bioavailability, and antioxidant potential

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    The apigenin-phospholipid phytosome (APLC) was developed to improve the aqueous solubility, dissolution, in vivo bioavailability, and antioxidant activity of apigenin. The APLC synthesis was guided by a full factorial design strategy, incorporating specific formulation and process variables to deliver an optimized product. The design-optimized formulation was assayed for aqueous solubility, in vitro dissolution, pharmacokinetics, and antioxidant activity. The pharmacological evaluation was carried out by assessing its effects on carbon tetrachloride-induced elevation of liver function marker enzymes in a rat model. The antioxidant activity was assessed by studying its effects on the liver antioxidant marker enzymes. The developed model was validated using the design-optimized levels of formulation and process variables. The physical-chemical characterization confirmed the formation of phytosomes. The optimized formulation demonstrated over 36-fold higher aqueous solubility of apigenin, compared to that of pure apigenin. The formulation also exhibited a significantly higher rate and extent of apigenin release in dissolution studies. The pharmacokinetic analysis revealed a significant enhancement in the oral bioavailability of apigenin from the prepared formulation, compared to pure apigenin. The liver function tests indicated that the prepared phytosome showed a significantly improved restoration of all carbon tetrachloride-elevated rat liver function marker enzymes. The prepared formulation also exhibited antioxidant potential by significantly increasing the levels of glutathione, superoxide dismutase, catalase, and decreasing the levels of lipid peroxidase. The study shows that phospholipid-based phytosome is a promising and viable strategy for improving the delivery of apigenin and similar phytoconstituents with low aqueous solubility

    Alternative approach to all-angle negative refraction in two-dimensional photonic crystals

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    We show that with an appropriate surface modification, a slab of photonic crystal can be made to allow wave transmission within the band gap. Furthermore, negative refraction and all-angle-negative-refraction (AANR) can be achieved by this surface modification in frequency windows that were not realized before in two-dimensional photonic crystals [C. Luo et al, Phys. Rev. B 65, 201104 (2002)]. This approach to AANR leads to new applications in flat lens imaging. Previous flat lens using photonic crystals requires object-image distance u+v less than or equal to the lens thickness d, u+v d. Our approach can be used to design flat lens with u+v=sd with s>>1, thus being able to image large and/or far away objects. Our results are confirmed by FDTD simulations.Comment: 5 pages, 9 eps figs in RevTex forma

    From chaos to disorder: Statistics of the eigenfunctions of microwave cavities

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    We study the statistics of the experimental eigenfunctions of chaotic and disordered microwave billiards in terms of the moments of their spatial distributions, such as the Inverse Participation Ratio (IPR) and density-density auto-correlation. A path from chaos to disorder is described in terms of increasing IPR. In the chaotic, ballistic limit, the data correspond well with universal results from random matrix theory. Deviations from universal distributions are observed due to disorder induced localization, and for the weakly disordered case the data are well-described by including finite conductance and mean free path contributions in the framework of nonlinear sigma models of supersymetry.Comment: 5 pages + 2 JPG figure

    Kaempferol-Phospholipid Complex: Formulation, and Evaluation of Improved Solubility, In Vivo Bioavailability, and Antioxidant Potential of Kaempferol

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    The current work describes the formulation and evaluation of a phospholipid complex of kaempferol toenhance the latter’s aqueous solubility, in vitro dissolution rate, in vivo antioxidant and hepatoprotectiveactivities, and oral bioavailability. The kaempferol-phospholipid complex was synthesized using a freeze-drying method with the formulation being optimized using a full factorial design (32) approach. The resultsinclude the validation of the mathematical model in order to ascertain the role of specific formulation andprocess variables that contribute favorably to the formulation’s development. The final product wascharacterized and confirmed by Differential Scanning Calorimetry (DSC), Fourier Transform InfraredSpectroscopy (FTIR), Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), and Powder X-rayDiffraction (PXRD) analysis. The aqueous solubility and the in vitro dissolution rate were enhanced comparedto that of pure kaempferol. The in vivo antioxidant properties of the kaempferol-phospholipid complex wereevaluated by measuring its impact on carbon tetrachloride (CCl4)-intoxicated rats. The optimizedphospholipid complex improved the liver function test parameters to a significant level by restoration of allelevated liver marker enzymes in CCl4-intoxicated rats. The complex also enhanced the in vivo antioxidantpotential by increasing levels of GSH (reduced glutathione), SOD (superoxide dismutase), catalase anddecreasing lipid peroxidation, compared to that of pure kaempferol. The final optimized phospholipidcomplex also demonstrated a significant improvement in oral bioavailability demonstrated by improvementsto key pharmacokinetic parameters, compared to that of pure kaempferol

    Duality between quantum and classical dynamics for integrable billiards

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    We establish a duality between the quantum wave vector spectrum and the eigenmodes of the classical Liouvillian dynamics for integrable billiards. Signatures of the classical eigenmodes appear as peaks in the correlation function of the quantum wave vector spectrum. A semiclassical derivation and numerical calculations are presented in support of the results. These classical eigenmodes can be observed in physical experiments through the auto-correlation of the transmission coefficient of waves in quantum billiards. Exact classical trace formulas of the resolvent are derived for the rectangle, equilateral triangle, and circle billiards. We also establish a correspondence between the classical periodic orbit length spectrum and the quantum spectrum for integrable polygonal billiards.Comment: 12 pages, 4 figure

    Households’ awareness and practices on Water, Sanitation and Hygiene (WASH) in an Arid Region of Northwestern Nigeria-Sokoto State

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    Water, Sanitation and Hygiene (WASH) accessibility is more critical in arid regions where rainfall is low and other water resources are scanty. This study assesses Households’ awareness and practices regarding WASH in Sokoto State, an arid region in Northwestern Nigeria. A total of 854 questionnaires were administered to respondents in addition to physical observations conducted. From the study, water scarcity was a major problem confronting the State, particularly in the dry season. The major water sources utilized were the unprotected hand dug wells (79.3%). The common water treatment methods used were filtration through cloth (72.1%). Water storage and collection attitudes and practices were rated as good as 69.0% of the respondents stored water in covered clay pots and 82.1% use cups with handle to draw water. Lack of funds led to poor excreta disposal systems and high open field defecation practices (78.9%). On the aspects of hygiene, children’s faeces were mostly disposed into bush (82.5%) and 55.6% did not use soap to wash hands after defecation. The major diseases reported in the communities included malaria, diarrhea and dysentery, therefore, there is a need for the provision of WASH facilities to combat these diseases. WASH education and financial empowerment are necessary towards protecting public health in the study area.&nbsp
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