992 research outputs found

    Traveling solitary wave solutions for the symmetric regularized long-wave equation

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    In this paper, we employ the extended tanh function method to nd the exact traveling wave solutions involving parameters of the symmetric regularized long- wave equation. When these parameters are taken to be special values, the solitary wave solutions are derived from the exact traveling wave solutions. These studies reveal that the symmetric regularized long-wave equation has a rich varietyof solutions

    Anticancer activity and DNA interaction of bis(pyridyl)allene-derived metal complexes

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    The constant need for novel drugs has prompted the scientific community to explore alternative structures to natural products and small and medium size organic compounds used in classic medicinal and pharmaceutical chemistry. Since the discovery of cisplatin, organometallic compounds have revealed great potential as metallodrugs and their development has exponentially grown in recent years. In this manuscript, we describe our efforts towards the synthesis of new metallodrugs by reaction of bis(pyridyl)allenes and metal complexes. Two classes of compounds are presented: one in which the allene structure is intact and the metal (Pd(II), Pt(IV) or Au(III)) coordinates to the pyridine-nitrogens; and another, in which one of the pyridines cyclises into a gold-activated allene to form ÎČ-N-stabilised gold carbenes. Both classes of compounds are active catalysts in important organic reactions, and are also promising antimicrobial, antifungal and anticancer agents. In this work, we describe the promising anticancer activity, against breast cancer cells, of the gold carbene complexes, and preliminary studies of their interaction with DNA, including non-canonical DNA structures. Our results have revealed an unusual selective stabilisation of hTeloC i-motif by one of the Au(III) carbene complexes, that opens up exciting opportunities for further development of novel DNA-binding metallodrugs

    Acceptability and feasibility of strategies to shield the vulnerable during the COVID-19 outbreak: a qualitative study in six Sudanese communities.

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    BACKGROUND: Shielding of high-risk groups from coronavirus disease (COVID-19) has been suggested as a realistic alternative to severe movement restrictions during the COVID-19 epidemic in low-income countries. The intervention entails the establishment of 'green zones' for high-risk persons to live in, either within their homes or in communal structures, in a safe and dignified manner, for extended periods of time during the epidemic. To our knowledge, this concept has not been tested or evaluated in resource-poor settings. This study aimed to explore the acceptability and feasibility of strategies to shield persons at higher risk of severe COVID-19 outcomes, during the COVID-19 epidemic in six communities in Sudan. METHODS: We purposively sampled participants from six communities, illustrative of urban, rural and forcibly-displaced settings. In-depth telephone interviews were held with 59 members of households with one or more members at higher risk of severe COVID-19 outcomes. Follow-up interviews were held with 30 community members after movement restrictions were eased across the country. All interviews were audio-recorded, transcribed verbatim, and analysed using a two-stage deductive and inductive thematic analysis. RESULTS: Most participants were aware that some people are at higher risk of severe COVID-19 outcomes but were unaware of the concept of shielding. Most participants found shielding acceptable and consistent with cultural inclinations to respect elders and protect the vulnerable. However, extra-household shielding arrangements were mostly seen as socially unacceptable. Participants reported feasibility concerns related to the reduced socialisation of shielded persons and loss of income for shielding families. The acceptability and feasibility of shielding strategies were reduced after movement restrictions were eased, as participants reported lower perception of risk in their communities and increased pressure to comply with social commitments outside the house. CONCLUSION: Shielding is generally acceptable in the study communities. Acceptability is influenced by feasibility, and by contextual changes in the epidemic and associated policy response. The promotion of shielding should capitalise on the cultural and moral sense of duty towards elders and vulnerable groups. Communities and households should be provided with practical guidance to implement feasible shielding options. Households must be socially, psychologically and financially supported to adopt and sustain shielding effectively

    Redox-dependent control of i-Motif DNA structure using copper cations

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    Previous computational studies have shown that Cu+ can act as a substitute for H+ to support formation of cytosine (C) dimers with similar conformation to the hemi-protonated base pair found in i-motif DNA. Through a range of biophysical methods, we provide experimental evidence to support the hypothesis that Cu+ can mediate C–C base pairing in i-motif DNA and preserve i-motif structure. These effects can be reversed using a metal chelator, or exposure to ambient oxygen in the air that drives oxidation of Cu+ to Cu2+, a comparatively weak ligand. Herein, we present a dynamic and redox-sensitive system for conformational control of an i-motif forming DNA sequence in response to copper cations

    Fermentation of deproteinized cheese whey powder solutions to ethanol by engineered Saccharomyces cerevisiae : effect of supplementation with corn steep liquor and repeated-batch operation with biomass recycling by flocculation

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    The lactose in cheese whey is an interesting substrate for the production of bulk commodities such as bio-ethanol, due to the large amounts of whey surplus generated globally. In this work, we studied the performance of a recombinant Saccharomyces cerevisiae strain expressing the lactose permease and intracellular ß-galactosidase from Kluyveromyces lactis in fermentations of deproteinized concentrated cheese whey powder solutions. Supplementation with 10 g/l of corn steep liquor significantly enhanced whey fermentation, resulting in the production of 7.4% (v/v) ethanol from 150 g/l initial lactose in shake-flask fermentations, with a corresponding productivity of 1.2 g/l/h. The flocculation capacity of the yeast strain enabled stable operation of a repeated-batch process in a 5.5-l air-lift bioreactor, with simple biomass recycling by sedimentation of the yeast flocs. During five consecutive batches, the average ethanol productivity was 0.65 g/l/h and ethanol accumulated up to 8% (v/v) with lactose-toethanol conversion yields over 80% of theoretical. Yeast viability (>97%) and plasmid retention (>84%) remained high throughout the operation, demonstrating the stability and robustness of the strain. In addition, the easy and inexpensive recycle of the yeast biomass for repeated utilization makes this process economically attractive for industrial implementation.Fundação para a CiĂȘncia e a Tecnologia (FCT)LACTOGAL-Produtos Alimentares S.A.Companhia Portuguesa de Amidos, S.A

    Measurement of the t(t)over-bar production cross section in the dilepton channel in pp collisions at √s=8 TeV

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    The top-antitop quark (t (t) over bar) production cross section is measured in proton-proton collisions at root s = 8 TeV with the CMS experiment at the LHC, using a data sample corresponding to an integrated luminosity of 5.3 fb(-1). The measurement is performed by analysing events with a pair of electrons or muons, or one electron and one muon, and at least two jets, one of which is identified as originating from hadronisation of a bottom quark. The measured cross section is 239 +/- 2 (stat.) +/- 11 (syst.) +/- 6 (lum.) pb, for an assumed top-quark mass of 172.5 GeV, in agreement with the prediction of the standard model

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  Όb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∌0) correlation that grows rapidly with increasing ÎŁETPb. A long-range “away-side” (Δϕ∌π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ÎŁETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁥2Δϕ modulation for all ÎŁETPb ranges and particle pT
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