1,646 research outputs found

    Study of the antibacterial activity of total extract and Petroleum ether, chloroform, ethyl acetate and aqueous fractions of aerial parts of heliotropium bacciferum against staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, E.coli, Salmonella enteritidis

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    Heliotropium bacciferum is One of the plants belonging to the family Boraginaceae , which is Restricted distribution in the south of Iran. It is used for Hypotension, fever, stomach ulcers in traditional medicine. In this study, the antibacterial effects of extracts and fractions of chloroform, ethyl acetate and aqueous, aerial parts of Heliotropium bacciferum Forssk was evaluated against five bacterial strains. The methanol extract were prepared using the percolation method. Fractions of chloroform, Petroleum ether, ethyl acetate, methanol and aqueous respectively by Liquid - Liquid fractionation of the total extract were prepared. The antibacterial activity against two Gram positive bacteria, three Gram negative bacterial using Minimum inhibitory concentration in microplate and well plate method. Results showed that H. bacciferum extracts exhibited a significant activity against strains Staphylococcus aureus, Bacillus cereus,Pseudomonas aeruginosa, E.coli, Salmonella enteritidis. MIC and well plate is between 7.6-125 ÎŒg/ml. The results of this study indicate that extracts of the plant H.bacciferum has a antimicrobial effect against strains are listed And among the extracts, aqueous part is that most antibacterial effect of the other fraction and then methanolic extract has the greatest effect

    Nonparametric liquefaction triggering and postliquefaction deformations

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    This study evaluates granular liquefaction triggering case-history data using a nonparametric approach. This approach assumes no functional form in the relationship between liquefied and nonliquefied cases as measured using cone penetration test (CPT) data. From a statistical perspective, this allows for an estimate of the threshold of liquefaction triggering unbiased by prior functional forms, and also provides a platform for testing existing published methods for accuracy and precision. The resulting threshold exhibits some unique trends, which are then interpreted based on postliquefaction deformation behavior. The range of postliquefaction deformations are differentiated into three zones: (1) large deformations associated with metastable conditions; (2) medium deformations associated with cyclic strain failure; and (3) small deformations associated with cyclic stress failure. Deformations are further defined based on the absence or presence of static driving shear stresses. This work presents a single simplified framework that provides quantitative guidance on triggering and qualitative guidance on deformation potential for quick assessment of risks associated with seismic soil liquefaction failure

    SU(1,1) symmetry of multimode squeezed states

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    We show that a class of multimode optical transformations that employ linear optics plus two-mode squeezing can be expressed as SU(1,1) operators. These operations are relevant to state-of-the-art continuous variable quantum information experiments including quantum state sharing, quantum teleportation, and multipartite entangled states. Using this SU(1,1) description of these transformations, we obtain a new basis for such transformations that lies in a useful representation of this group and lies outside the often-used restriction to Gaussian states. We analyze this basis, show its application to a class of transformations, and discuss its extension to more general quantum optical networks

    Choice Hygiene for “Consumer Neuroscientists”? Ethical Considerations and Proposals for Future Endeavours

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    Is the use of psychological and neuroscientific methods for neuromarketing research always aligned with the principles of ethical research practice? Some neuromarketing endeavours have passed from informing consumers about available options, to helping to market as many products to consumers as possible. Needs are being engineered, using knowledge about the human brain to increase consumption further, regardless of individual, societal and environmental needs and capacities. In principle, the ground ethical principle of any scientist is to further individual, societal and environmental health and well-being with their work. If their findings can be used for the opposite, this must be part of the scientist’s considerations before engaging in such research and to make sure that the risks for misuse are minimised. Against this backdrop, we provide a series of real-life examples and a non-exhaustive literature review, to discuss in what way some practices in the neuromarketing domain may violate the Helsinki Declaration of Experimentation with Human Subjects. This declaration was set out to regulate biomedical research, but has since its inception been applied internationally also to behavioural and social research. We illustrate, point by point, how these ground ethical principles should be applied also to the neuromarketing domain. Indisputably, the growth in consumption is required due to current prevalent economical models. Thus, in the final part of the paper, we discuss how alternative models may be promotable to a larger public, aided by more ethical marketing endeavours, based on neuroscientific discoveries about the human brain. We propose this as a philosophical question, a point of discussion for the future, to make neuromarketing as a discipline, fit for the future, respecting the ethical implications of this research

    Insights on Entanglement Entropy in 1+11+1 Dimensional Causal Sets

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    Entanglement entropy in causal sets offers a fundamentally covariant characterisation of quantum field degrees of freedom. A known result in this context is that the degrees of freedom consist of a number of contributions that have continuum-like analogues, in addition to a number of contributions that do not. The latter exhibit features below the discreteness scale and are excluded from the entanglement entropy using a "truncation scheme". This truncation is necessary to recover the standard spatial area law of entanglement entropy. In this paper we build on previous work on the entanglement entropy of a massless scalar field on a causal set approximated by a 1+1D causal diamond in Minkowski spacetime. We present new insights into the truncated contributions, including evidence that they behave as fluctuations and encode features specific to a particular causal set sprinkling. We extend previous results in the massless theory to include R\'enyi entropies and include new results for the massive theory. We also discuss the implications of our work for the treatment of entanglement entropy in causal sets in more general settings.Comment: 25 pages, 18 figure

    DFT-D3 study of H 2 and N 2 chemisorption over cobalt promoted Ta 3 N 5-(100), (010) and (001) surfaces

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    The reactants for ammonia synthesis have been studied, employing density functional theory (DFT), with respect to their adsorption on tantalum nitride surfaces. The adsorption of nitrogen was found to be mostly molecular and non-activated with side-on, end-on and tilt configurations. At bridging nitrogen sites (Ta–N–Ta) it results in an azide functional group formation with a formation energy of 205 kJ mol−1. H2 was found also to chemisorb molecularly with an adsorption energy in the range −81 to −91 kJ mol−1. At bridging nitrogen sites it adsorbs dissociatively forming >NH groups with an exothermic formation energy of −175 kJ mol−1 per H2. The nitrogen vacancy formation energies were relatively high compared to other metal nitrides found to be 2.89 eV, 2.32 eV and 1.95 eV for plain, surface co-adsorbed cobalt and sub-surface co-adsorbed cobalt Ta3N5-(010). Co-adsorption of cobalt was found to occur mostly at nitrogen rich sites of the surface with an adsorption energy that ranged between −200 to −400 kJ mol−1. The co-adsorption of cobalt was found to enhance the dissociation of molecular hydrogen on the surface of Ta3N5. The studies offer significant new insight with respect to the chemistry of N2 and H2 with tantalum nitride surfaces in the presence of cobalt promoters

    A comparative analysis of the mechanisms of ammonia synthesis on various catalysts using density functional theory

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    In this review, we present the recent progress in ammonia synthesis research using density functional theory (DFT) calculations on various industrial catalysts, metal nitrides and nano-cluster-supported catalysts. The mechanism of ammonia synthesis on the industrial Fe catalyst is generally accepted to be a dissociative mechanism. We have recently found, using DFT techniques, that on Co₃Mo₃N (111) surfaces, an associative mechanism in the synthesis of ammonia can offer a new low-energy pathway that was previously unknown. In particular, we have shown that metal nitrides that are also known to have high activity for ammonia synthesis can readily form nitrogen vacancies which can activate dinitrogen, thereby promoting the associative mechanism. These fundamental studies suggest that a promising route to the discovery of low-temperature ammonia synthesis catalysts will be to identify systems that proceed via the associative mechanism, which is closer to the nitrogen-fixation mechanism occurring in nitrogenases

    Cerebritis and Neutropenia in A Child with ana Negative Lupus

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    ObjectiveSystemic lupus erythematosus (SLE), an autoimmune systemic disease with unknown etiology, affects virtually every part of the body; involvement of the central nervous system (CNS) is one of the major causes of morbidity and mortality in systemic lupus erythematosus (SLE) patients and is the least understood aspect of the disease. neutropenia is very uncommon in childhood lupus. True negative anti nuclear antibody (ANA) tests in patients with lupus are now very rare. The patient reported here was a 12-year-old girl with ANA negative lupus cerebritis who presented with left hemiparesia after a generalized seizure, with neutropenia observed during its course

    Measurement of the penetration depth and coherence length of MgB2 in all directions using transmission electron microscopy

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    We demonstrate that images of flux vortices in a superconductor taken with a transmission electron microscope can be used to measure the penetration depth and coherence length in all directions at the same temperature and magnetic field. This is particularly useful for MgB2_2, where these quantities vary with the applied magnetic field and values are difficult to obtain at low field or in the cc-direction. We obtained images of flux vortices from an MgB2_2 single crystal cut in the acac plane by focussed ion beam milling and tilted to 45∘45^\circ with respect to the electron beam about its aa axis. A new method was developed to simulate these images which accounted for vortices with a non-zero core in a thin, anisotropic superconductor and a simplex algorithm was used to make a quantitative comparison between the images and simulations to measure the penetration depths and coherence lengths. This gave penetration depths Λab=100±35\Lambda_{ab}=100\pm 35 nm and Λc=120±15\Lambda_c=120\pm 15 nm at 10.8 K in a field of 4.8 mT. The large error in Λab\Lambda_{ab} is a consequence of tilting the sample about aa and had it been tilted about cc, the errors would be reversed. Thus, obtaining the most precise values requires taking images of the flux lattice with the sample tilted in more than one direction. In a previous paper, we obtained a more precise value using a sample cut in the abab plane. Using this value gives Λab=107±8\Lambda_{ab}=107\pm 8 nm, Λc=120±15\Lambda_c=120\pm 15 nm, Οab=39±11\xi_{ab}=39\pm 11 nm and Οc=35±10\xi_c=35\pm 10 nm which agree well with measurements made using other techniques. The experiment required two days to conduct and does not require large-scale facilities. It was performed on a very small sample: 30×1530\times 15 microns and 200 nm thick so this method could prove useful for characterising new superconductors where only small single crystals are available.This work was funded by the Royal Society. Work at Eidgenossische Technische Hochschule, ZĂŒrich was supported by the Swiss National Science Foundation and the National Center of Competence in Research programme “Materials with Novel Electronic Properties.”This is the accepted manuscript for a paper published in Physical Review B, 91, 054505, 5 February 2015, DOI: 10.1103/PhysRevB.91.05450

    The integration of experiment and computational modelling in heterogeneously catalysed ammonia synthesis over metal nitrides

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    In this perspective we present recent experimental and computational progress in catalytic ammonia synthesis research on metal nitrides involving a combined approach. On this basis, it suggested that the consideration of nitrogen vacancies in the synthesis of ammonia can offer new low energy pathways that were previously unknown. We have shown that metal nitrides that are also known to have high activity for ammonia synthesis can readily form nitrogen vacancies on their surfaces. These vacancies adsorb dinitrogen much more strongly than the defect-free surfaces and can efficiently activate the strong N–N triple bond. These fundamental studies suggest that heterogeneously catalysed ammonia synthesis over metal nitrides is strongly affected by bulk and surface defects and that further progress in the discovery of low temperature catalysts relies on more careful consideration of nitrogen vacancies. The potential occurrence of an associative pathway in the case of the Co3Mo3N catalytic system provides a possible link with enzymatic catalysis, which will be of importance in the design of heterogeneous catalytic systems operational under process conditions of reduced severity which are necessary for the development of localised facilities for the production of more sustainable “green” ammonia
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