2,273 research outputs found

    Randomly Diluted e_g Orbital-Ordered Systems

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    Dilution effects on the long-range ordered state of the doubly degenerate ege_g orbital are investigated. Quenched impurities without the orbital degree of freedom are introduced in the orbital model where the long-range order is realized by the order-from-disorder mechanism. It is shown by the Monte-Carlo simulation and the cluster-expansion method that a decrease in the orbital ordering temperature by dilution is remarkable in comparison with that in the randomly diluted spin models. Tiltings of orbitals around impurity cause this unique dilution effects on the orbital systems. The present theory provides a new view point for the recent experiments in KCu1x_{1-x}Znx_xF3_3.Comment: 4 pages, 4 figure

    Marine polysaccharide multilayers: PH responsive systems for the surface modification of tissue engineering scaffolds

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    [Excerpt] The success of some polymeric scaffolds for Tissue Engineering is hindered by its surface chemistry, which in many cases leads to a significant foreign body response. To overcome this, the present project intend to explore a strategy of surface modification through electrostatic self-assembly, first reported in the 1990s, by the construction of multilayered systems by assembling a polycation and a polyanion in an alternate fashion. [...]info:eu-repo/semantics/publishedVersio

    Agrobacterium Tumefaciens-Mediated Transformation of Perennial Ryegrass (\u3ci\u3eLolium Perenne\u3c/i\u3e L.)

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    An Agrobacterium tumefaciens-mediated transformation method has several advantages. However, this method has no example of success in perennial ryegrass (Lolium perenne L.). Since Lolium species are outcrossing, one cultivar consists of many genotypes. Each genotype can show a different ability for callus formation and plant regeneration (Takahashi et al., 2004). Thus, it is important to select a good genotype for efficient and stable transformation. If the plant is maintained in vitro, we can perform transformation using calli induced from shoot tips of the same genotype at any time. Our objective is to confirm an A. tumefaciens-mediated transformation method for perennial ryegrass and to screen for suitable genotype

    Prevalência de lesões cervicais não cariadas em doentes de uma clínica universitária

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    Poster apresentado no XXXIV Congresso Anual da Sociedade Portuguesa de Estomatologia e Medicina Dentária (SPEMD), 9-11 Outubro 2014, Auditórios do Centro Hospitalar e Universitário de Coimbra.Under a Creative Commons license - http://creativecommons.org/licenses/by-nc-nd/3.0

    Cardiac Magnetic Resonance in the Assessment of Pericardial Abnormalities: a Case Series

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    Background: Cardiac magnetic resonance (CMR) has a unique role in evaluating pericardial disease, permitting non-invasive tissue analysis, and haemodynamic assessment. Case summary: In Case 1 of recurrent pericarditis, CMR confirmed reactivation of inflammation with late gadolinium enhancement and native T1/T2 mapping techniques, prompting therapeutic changes. In constrictive pericarditis, CMR is the only modality capable of differentiating a subacute potentially reversible form (Case 2), from a chronic, burnt out irreversible phase characterized by constrictive physiology (Case 3). Discussion: Cardiac magnetic resonance is an effective tool to tailor individual therapy, particularly in cases of recurrent and constrictive pericarditis. Late gadolinium enhancement provides diagnostic and prognostic information, and multiparametric mapping has emerged as a promising tool with incremental diagnostic value.info:eu-repo/semantics/publishedVersio

    Nanostructured natural-based polyelectrolyte multilayers to agglomerate chitosan particles into scaffolds for tissue engineering

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    The Layer-by-Layer (LbL) deposition technique is a self-assembly process that allows the coating of material's surface with nanostructured layers of polyelectrolytes, allowing to control several surface properties. This technique presents some advantages when compared with other thin film assembly techniques like having the possibility to coat surfaces with complex geometries in mild conditions or to incorporate active compounds. Tissue engineering involves typically the use of porous biodegradable scaffolds for the temporary support of cells. Such structures can be produced by agglomeration of micro-spheres that needs to be fixed into a three dimensional structure. In this work we suggest the use of LbL to promote such mechanical fixation in free-formed micro-spheres assemblies and simultaneously to control the properties of its surface. For the proof of concept the biological performance of chitosan/alginate multilayers is first investigated in two-dimensional models in which the attachment and proliferation of L929 and ATDC5 cells are studied in function of the number of layers and the nature of the final layer. Scaffolds prepared by agglomeration of chitosan particles using the same multilayered system were processed and characterized; it was found that they could support the attachment and proliferation of ATDC5 cells. This study suggests that LbL can be used as a versatile methodology to prepare scaffolds by particle agglomeration that could be suitable for tissue engineering applications.Fundo Europeu de Desenvolvimento Regional (FEDER) através do Programa Operacional de Cooperação Transfronteiriça Espanha Portugal 2007-2013 (POCTEP)Fundação para a Ciência e a Tecnologia (FCT

    Crown Rust Resistance of Italian Ryegrass Cultivar ‘Axis’ to an Isolate from Japan

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    Crown rust (Puccinia coronata) is one the most serious diseases of Italian ryegrass. Crown rust resistance genes in Italian ryegrass have been identified from \u27Yamaiku130\u27 and ‘Harukaze’. The aim of this study was to identify novel major resistance genes for gene pyramiding in order to develop cultivars with high levels of durable resistance to crown rus

    Association between Choroidal Characteristics and Systemic Severity in Amyloidosis

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    PURPOSE: This study aimed to describe the choroidal features of ocular amyloidosis using multimodal imaging, to correlate these findings with systemic involvement, and to propose a choroidal grading system. METHODS: Eleven patients with systemic amyloidosis were reviewed retrospectively. Each case was assigned a grade according to the severity of choroidal findings as determined by both enhanced depth imaging optical coherence tomography and indocyanine green angiography. The severity of systemic amyloidosis was then correlated with the choroidal involvement. RESULTS: On indocyanine green angiography, all patients exhibited hyperfluorescent spots in the late stage and were classified according to preexisting criteria. On enhanced depth imaging optical coherence tomography, hyperreflective foci were seen in the choriocapillaris and Sattler's layer in Grade 1, partial loss of Sattler's layer was additionally seen in Grade 2, and a dense hyperreflective Haller's layer was seen in Grade 3. Choroidal grading scores were significantly correlated with the systemic severity score (P = 0.0014, Pearson's correlation coefficient; ρ = 0.83). CONCLUSION: With ocular amyloidosis, evaluation of choroidal characteristics using multimodal imaging may serve as a biomarker for systemic involvement

    Shape control of QDs studied by cross-sectional scanning tunneling microscopy

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    In this cross-sectional scanning tunneling microscopy study we investigated various techniques to control the shape of self-assembled quantum dots (QDs) and wetting layers (WLs). The result shows that application of an indium flush during the growth of strained InGaAs/GaAs QD layers results in flattened QDs and a reduced WL. The height of the QDs and WLs could be controlled by varying the thickness of the first capping layer. Concerning the technique of antimony capping we show that the surfactant properties of Sb result in the preservation of the shape of strained InAs/InP QDs during overgrowth. This could be achieved by both a growth interrupt under Sb flux and capping with a thin GaAsSb layer prior to overgrowth of the uncapped QDs. The technique of droplet epitaxy was investigated by a structural analysis of strain free GaAs/AlGaAs QDs. We show that the QDs have a Gaussian shape, that the WL is less than 1 bilayer thick, and that minor intermixing of Al with the QDs takes place.Comment: 7 pages, 10 figure
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