658 research outputs found

    Tannic acid is not mutagenic in germ cells but weakly genotoxic in somatic cells of Drosophila melanogaster

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    Tannic acid (TA) was tested for genotoxic activity in three different assays (1-3) in Drosophila melanogaster by feeding of larvae or adult flies. TA did not induce sex-linked recessive lethals (1) nor sex-chromosome loss, mosaicism or non-disjunction (2) in male germ cells. In the wing somatic mutation and recombination test (SMART) (3) TA was found to be toxic for larvae of the high bioactivation cross and produced a weak positive response. These results suggest that this compound, when administered orally to larvae or adults of D.melanogaster, is not mutagenic and clastogenic in male germ cells, but weakly genotoxic in somatic cells of the wing imaginal dis

    Quiropterofauna Do Cerrado Leste Maranhense, Brasil, Com Ocorrência De Novos Registros. Biota Neotropica

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    In Brazil, 179 bat species have been recorded to date, representing 68 genera and nine families. Few data are available on the bat fauna of the state of Maranhão, so the present study was based on a survey of the bat fauna of the Inhamum Municipal Environmental Protection Area (APA Inhamum) in the Cerrado savanna of the eastern extreme of the state. This inventory provides new records of bat species for the state of Maranhão and the Cerrado biome. A total of 31 species (four families) were collected, representing 39% of the bat species known to occur in Maranhão and 28.71% of the species described for the Cerrado. The family Phyllostomidae was the most diverse, with 23 species (74.20% of the total), and also the most abundant, with 86.09% of the specimens collected. The Molossidae (four species) was the second most diverse, followed by the Vespertilionidae (three species) and the Emballonuridae (one species). Carollia perspicillata was the most abundant species (28%).The records of Artibeus fimbriatus and Platyrrhinus fusciventris are the first for the Cerrado and were also recorded in Maranhão for the first time. The cumulative species curve did not reach an asymptote. The species Dermanura gnoma, Lasiurus blossevillii, Lasiurus ega, Micronycteris schmidtorum, Molossops temminckii, Platyrrhinus cf. recifinus, Phylloderma stenops and Trachops cirrhosus, were also recorded in Maranhão for the first time demonstrating the value of for mammal inventories and emphasizing the need for further surveys in this poorly-known region. © 2016, Universidade Estadual de Campinas UNICAMP. All Rights Reserved.16

    Anatomical Features Of The Urethra And Urinary Bladder Catheterization In Female Mice And Rats. An Essential Translational Tool [características Anatômicas Da Cateterização Da Uretra E Bexiga De Camundongos E Ratos Fêmeas. Instrumento Essencial Na Pesquisa Pré Clínica]

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    PURPOSE: To present fundamental anatomical aspects and technical skills necessary to urethra and urinary bladder catheterization in female mice and rats. METHODS: Urethral and bladder catheterization has been widely utilized for carcinogenesis and cancer research and still remains very useful in several applications: from toxicological purposes as well as inflammatory and infectious conditions to functional aspects as bladder dynamics and vesicoureteral reflux, among many others. RESULTS: Animal models are in the center of translational research and those involving rodents are the most important nowadays due to several advantages including human reproducibility, easy handling and low cost. CONCLUSIONS: Although technical and anatomical pearls for rodent urethral and bladder access are presented as tackles to the advancement of lower urinary tract preclinical investigation in a broaden sight, restriction to female animals hampers the male microenvironment, demanding future advances.26SUPPL. 2106110Reis, L.O., Fávaro, W.J., Ferreira, U., Billis, A., Fazuoli, M.G., Cagnon, V.H., Evolution on experimental animal model for upper urothelium carcinogenesis (2010) World J Urol, 28, pp. 499-505Mulder, G.J., Scholtens, E., Meijer, D.K., Collection of metabolites in bile and urine from the rat (1981) Methods Enzymol, 77, pp. 21-30Krinke, G.J., (2000) The Laboratory Rat, , San Diego, CA: Academic PressPhillips, J.I., Davies, I., The comparative morphology of the bladder and urethra in young and old female C57BL/Icrfat mice (1980) Exp Geront, 15, pp. 551-562Andersson, K.E., Arner, A., Urinary bladder contraction and relaxation: Physiology and pathophysiology (2004) Physiol Rev, 84, pp. 935-986Reis, L.O., Pereira, T.C., Favaro, W.J., Cagnon, V.H., Lopes-Cendes, I., Ferreira, U., Experimental animal model and RNA interference: A promising association for bladder cancer research (2009) World J Urol, 27, pp. 353-361Marini, R.P., Esteves, M.I., Fox, J.G., A technique for catheterization of the urinary bladder in the ferret (1994) Lab Anim, 28, pp. 155-15

    Hidden non-Fermi liquid behavior due to crystal field quartet

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    We study a realistic Kondo model for crystal field quartet ground states having magnetic and non-magnetic (quadrupolar) exchange couplings with conduction electrons, using the numerical renormalization group method. We focus on a local effect dependent on singlet excited states coupled to the quartet, which reduces the non-magnetic coupling significantly and drives non-Fermi liquid behavior observed in the calculated quadrupolar susceptibility. A crossover from the non-Fermi liquid state to the Fermi liquid state is characterized by a small energy scale very sensitive to the non-magnetic coupling. On the other hand, the Kondo temperature observed in the magnetic susceptibility is less sensitive. The different crystal-field dependence of the two exchange couplings may be related to the different xx dependence of quadrupolar and magnetic ordering temperatures in Cex_xLa1x_{1-x}B6_6.Comment: 7 pages, 5 EPS figures, REVTe

    Order and nFl Behavior in UCu4Pd

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    We have studied the role of disorder in the non-Fermi liquid system UCu4Pd using annealing as a control parameter. Measurement of the lattice parameter indicates that this procedure increases the crystallographic order by rearranging the Pd atoms from the 16e to the 4c sites. We find that the low temperature properties depend strongly on annealing. Whereas the non-Fermi liquid behavior in the specific heat can be observed over a larger temperature range after annealing, the clear non-Fermi liquid behavior of the resistivity of the unannealed sample below 10 K disappears. We come to the conclusion that this argues against the Kondo disorder model as an explanation for the non-Fermi liquid properties of both as-prepared and annealed UCu4Pd

    Localized spin ordering in Kondo lattice models

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    Using a non-Abelian density matrix renormalization group method we determine the phase diagram of the Kondo lattice model in one dimension, by directly measuring the magnetization of the ground-state. This allowed us to discover a second ferromagnetic phase missed in previous approaches. The phase transitions are found to be continuous. The spin-spin correlation function is studied in detail, and we determine in which regions the large and small Fermi surfaces dominate. The importance of double-exchange ordering and its competition with Kondo singlet formation is emphasized in understanding the complexity of the model.Comment: Revtex, 4 pages, 4 eps figures embedde

    Unified order-disorder vortex phase transition in high-Tc superconductors

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    The diversity of vortex melting and solid-solid transition lines measured in different high-Tc_{c} superconductors is explained, postulating a unified order-disorder phase transition driven by both thermally- and disorder-induced fluctuations. The temperature dependence of the transition line and the nature of the disordered phase (solid, liquid, or pinned liquid) are determined by the relative contributions of these fluctuations and by the pinning mechanism. By varying the pinning mechanism and the pinning strength one obtains a spectrum of monotonic and non-monotonic transition lines similar to those measured in Bi2_{2}Sr2_{2}CaCu2_{2}O%_{8}, YBa2_{2}Cu3_{3}O7δ_{7-\delta}, Nd1.85_{1.85}Ce0.15_{0.15}CuO%_{4-\delta}, Bi1.6_{1.6}Pb0.4_{0.4}Sr2_{2}CaCu2_{2}O8+δ_{8+\delta} and (La0.937% _{0.937}Sr0.063_{0.063})2_{2}CuO4_{4}Comment: To be published in Phys. Rev. B Rapid Com

    Disorder and thermally driven vortex-lattice melting in La{2-x}Sr{x}CuO{4} crystals

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    Magnetization measurements in La{2-x}Sr{x}CuO{4} crystals indicate vortex order-disorder transition manifested by a sharp kink in the second magnetization peak. The transition field exhibits unique temperature dependence, namely a strong decrease with temperature in the entire measured range. This behavior rules out the conventional interpretation of a disorder-driven transition into an entangled vortex solid phase. It is shown that the transition in La{2-x}Sr{x}CuO{4} is driven by both thermally- and disorder-induced fluctuations, resulting in a pinned liquid state. We conclude that vortex solid-liquid, solid-solid and solid to pinned-liquid transitions are different manifestations of the same thermodynamic order-disorder transition, distinguished by the relative contributions of thermal and disorder-induced fluctuations.Comment: To be published in phys. Rev. B Rapid Com

    Dynamic Scaling in Diluted Systems Phase Transitions: Deactivation trough Thermal Dilution

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    Activated scaling is confirmed to hold in transverse field induced phase transitions of randomly diluted Ising systems. Quantum Monte Carlo calculations have been made not just at the percolation threshold but well bellow and above it including the Griffiths-McCoy phase. A novel deactivation phenomena in the Griffiths-McCoy phase is observed using a thermal (in contrast to random) dilution of the system.Comment: 4 pages, 4 figures, RevTe

    On the critical behavior of disordered quantum magnets: The relevance of rare regions

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    The effects of quenched disorder on the critical properties of itinerant quantum antiferromagnets and ferromagnets are considered. Particular attention is paid to locally ordered spatial regions that are formed in the presence of quenched disorder even when the bulk system is still in the paramagnetic phase. These rare regions or local moments are reflected in the existence of spatially inhomogeneous saddle points of the Landau-Ginzburg-Wilson functional. We derive an effective theory that takes into account small fluctuations around all of these saddle points. The resulting free energy functional contains a new term in addition to those obtained within the conventional perturbative approach, and it comprises what would be considered non-perturbative effects within the latter. A renormalization group analysis shows that in the case of antiferromagnets, the previously found critical fixed point is unstable with respect to this new term, and that no stable critical fixed point exists at one-loop order. This is contrasted with the case of itinerant ferromagnets, where we find that the previously found critical behavior is unaffected by the rare regions due to an effective long-ranged interaction between the order parameter fluctuations.Comment: 16 pp., REVTeX, epsf, 2 figs, final version as publishe
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