174 research outputs found

    Molecular coupling of light with plasmonic waveguides

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    We use molecules to couple light into and out of microscale plasmonic waveguides. Energy transfer, mediated by surface plasmons, from donor molecules to acceptor molecules over ten micrometer distances is demonstrated. Also surface plasmon coupled emission from the donor molecules is observed at similar distances away from the excitation spot. The lithographic fabrication method we use for positioning the dye molecules allows scaling to nanometer dimensions. The use of molecules as couplers between far-field and near-field light offers the advantages that no special excitation geometry is needed, any light source can be used to excite plasmons and the excitation can be localized below the diffraction limit. Moreover, the use of molecules has the potential for integration with molecular electronics and for the use of molecular self-assembly in fabrication. Our results constitute a proof-of-principle demonstration of a plasmonic waveguide where signal in- and outcoupling is done by molecules.Comment: 9 pages, 5 figure

    A comparative analysis of meat inspection data as an information source of the health and welfare of broiler chickens based on Finnish data

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    The comprehensive, reliable, and comparable meat inspection (MI) data of broiler chickens (i.e. broilers) are essential for the monitoring and surveillance of broiler health and welfare at the national and European Union (EU) levels. We compared the condemnation causes issued to broiler carcasses during MI in four large Finnish broiler slaughterhouses (SHs) by investigating the similarities and differences between local MI instructions used in the SHs. The way in which MI condemnations were recorded in the Finnish Food Authority's (FFA's) MI statistics were also explored. We additionally analysed the FFA's official MI data from the 2015-2019 period. The study showed that the MI criteria used in the SHs differed from one another regarding how severe or extensive a broiler defect or disease must be to cause condemnation during MI. In Finland, the annual total condemnation prevalence of whole broilers varied between 2.6% and 4.8% in 2015-2019, and a significant difference was observed between the SHs' monthly total condemnation prevalences, except in two SH pairs. Mistakes in recording the FFA's MI statistics and differences in the SH operators' reasons to reject broilers from the food chain affect the comparability of the condemnation prevalences between the SHs. Only half of the SHs partially condemned broiler carcasses and collected data concerning these condemnations. Cellulitis (0.3-1.0%), ascites (0.3-0.4%), and body cavity disorders (0.2-0.3%) were the most common causes for condemning whole broiler carcasses in 2015-2019. The MI data can be used for monitoring and surveillance purposes only once the differences between the SH data and data reliability are known. Although the harmonization of all condemnation causes is impossible, harmonizing the condemnations of carcasses with diseases that most threaten broiler health and welfare and cause the largest economic losses would be important.Peer reviewe

    New physics in ttbar spin correlations at the Tevatron

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    We show that the angular distributions of leptons or jets due to ttbar spin correlations allow a determination of the top chromomagnetic moment kappa with an accuracy of order 0.1. The method is quite insensitive to background, event reconstruction, and other experimental uncertainties. The total event number is important, so we suggest the inclusion of all-hadronic events.Comment: 13 pages, 3 figures, two references added and cosmetic change

    Creation of ultracold molecules from a Fermi gas of atoms

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    Since the realization of Bose-Einstein condensates (BEC) in atomic gases an experimental challenge has been the production of molecular gases in the quantum regime. A promising approach is to create the molecular gas directly from an ultracold atomic gas; for example, atoms in a BEC have been coupled to electronic ground-state molecules through photoassociation as well as through a magnetic-field Feshbach resonance. The availability of atomic Fermi gases provides the exciting prospect of coupling fermionic atoms to bosonic molecules, and thus altering the quantum statistics of the system. This Fermi-Bose coupling is closely related to the pairing mechanism for a novel fermionic superfluid proposed to occur near a Feshbach resonance. Here we report the creation and quantitative characterization of exotic, ultracold 40^{40}K2_2 molecules. Starting with a quantum degenerate Fermi gas of atoms at T < 150 nanoKelvin we scan over a Feshbach resonance to adiabatically create over a quarter million trapped molecules, which we can convert back to atoms by reversing the scan. The small binding energy of the molecules is controlled by detuning from the Feshbach resonance and can be varied over a wide range. We directly detect these weakly bound molecules through rf photodissociation spectra that probe the molecular wavefunction and yield binding energies that are consistent with theory

    Natural Thermal and Magnetic Entanglement in 1D Heisenberg Model

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    We investigate the entanglement between any two spins in a one dimensional Heisenberg chain as a function of temperature and the external magnetic field. We find that the entanglement in an antiferromagnetic chain can be increased by increasing the temperature or the external field. Increasing the field can also create entanglement between otherwise disentangled spins. This entanglement can be confirmed by testing Bell's inequalities involving any two spins in the solid.Comment: 4 pages, 5 figure

    Avaliação da citotoxicidade de extratos hidroetanólicos de genótipos de açaí (Euterpe oleracea) em células SH-SY5Y.

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    Danos oxidativos induzidos pelo desequilíbrio entre a geração de espécies reativas de oxigênio (EROs) e sistemas antioxidantes estão associados a diversas doenças, entre as quais as doenças neurodegenerativas. O sistema nervoso é particularmente suscetível a danos oxidativos devido ao alto consumo de oxigênio e baixo nível de antioxidantes. Assim, a inserção na dieta de alimentos que possuam compostos antioxidantes podem ser uma alternativa para a contenção de danos oxidativos aos tecidos biológicos, entre estes, o tecido nervoso. O objetivo deste estudo foi avaliar a toxicidade de seis diferentes genótipos de açaí (Euterpe oleracea) do programa de melhoramento genético desenvolvido pela Embrapa Amazônia Oriental em células SH-SY5Y. Os resultados demonstram que, em geral, os genótipos não induziram citotoxicidade podendo ser uma alternativa para fins nutricionais

    Structural and biochemical characterization of the exopolysaccharide deacetylase Agd3 required for Aspergillus fumigatus biofilm formation

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    The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Deletion of a gene encoding a putative deacetylase, Agd3, leads to defects in GAG deacetylation, biofilm formation, and virulence. Here, we show that Agd3 deacetylates GAG in a metal-dependent manner, and is the founding member of carbohydrate esterase family CE18. The active site is formed by four catalytic motifs that are essential for activity. The structure of Agd3 includes an elongated substrate-binding cleft formed by a carbohydrate binding module (CBM) that is the founding member of CBM family 87. Agd3 homologues are encoded in previously unidentified putative bacterial exopolysaccharide biosynthetic operons and in other fungal genomes. The exopolysaccharide galactosaminogalactan (GAG) is an important virulence factor of the fungal pathogen Aspergillus fumigatus. Here, the authors study an A. fumigatus enzyme that deacetylates GAG in a metal-dependent manner and constitutes a founding member of a new carbohydrate esterase family.Bio-organic Synthesi
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