1,505 research outputs found

    Metalanguage in L1 English-speaking 12-year-olds: which aspects of writing do they talk about?

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    Traditional psycholinguistic approaches to metalinguistic awareness in L1 learners elicit responses containing metalanguage that demonstrates metalinguistic awareness of pre-determined aspects of language knowledge. This paper, which takes a more ethnographic approach, demonstrates how pupils are able to engage their own focus of metalanguage when reflecting on their everyday learning activities involving written language. What is equally significant is what their metalanguage choices reveal about their understanding and application of written language concepts

    Effect of the surface chemical composition and of added metal cation concentration on the stability of metal nanoparticles synthesized by pulsed laser ablation in water

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    Metal nanoparticles (NPs) made of gold, silver, and platinum have been synthesized by means of pulsed laser ablation in liquid aqueous solution. Independently from the metal nature, all NPs have an average diameter of 10 ± 5 nm. The ζ-potential values are:-62 ± 7 mV for gold,-44 ± 2 mV for silver and-58 ± 3 for platinum. XPS analysis demonstrates the absence of metal oxides in the case of gold and silver NPs. In the case of platinum NPs, 22% of the particle surface is ascribed to platinum oxidized species. This points to a marginal role of the metal oxides in building the negative charge that stabilizes these colloidal suspensions. The investigation of the colloidal stability of gold NPs in the presence of metal cations shows these NPs can be destabilized by trace amounts of selected metal ions. The case of Ag+ is paradigmatic since it is able to reduce the NP ζ-potential and to induce coagulation at concentrations as low as 3 μM, while in the case of K+ the critical coagulation concentration is around 8 mM. It is proposed that such a huge difference in destabilization power between monovalent cations can be accounted for by the difference in the reduction potential

    CHA2DS2-VASc Score Predicts Adverse Outcome in Patients with Simple Congenital Heart Disease Regardless of Cardiac Rhythm

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    Adult patients with simple congenital heart disease (sACHD) represent an expanding population vulnerable to atrial arrhythmias (AA). CHA2DS2-VASc score estimates thromboembolic risk in non-valvular atrial fibrillation patients. We investigated the prognostic role of CHA2DS2-VASc score in a non-selected sACHD population regardless of cardiac rhythm. Between November 2009 and June 2018, 427 sACHD patients (377 in sinus rhythm, 50 in AA) were consecutively referred to our ACHD service. Cardiovascular hospitalization and/or all-cause death were considered as composite primary end-point. Patients were divided into group A with CHA2DS2-VASc score = 0 or 1 point, and group B with a score greater than 1 point. Group B included 197 patients (46%) who were older with larger prevalence of cardiovascular risk factors than group A. During a mean follow-up of 70\ua0months (IQR 40\u201393), primary end-point occurred in 94 patients (22%): 72 (37%) in group B and 22 (10%, p < 0.001) in group A. Rate of death for all causes was also significantly higher in the group B than A (22% vs 2%, respectively, p < 0.001). Multivariable Cox regression analysis revealed that CHA2DS2-VASc score was independently related to the primary end-point (HR 1.84 [1.22\u20132.77], p = 0.004) together with retrospective AA, stroke/TIA/peripheral thromboembolism and diabetes. Furthermore, CHA2DS2-VASc score independently predicted primary end-point in the large subgroup of 377 patients with sinus rhythm (HR 2.79 [1.54\u20135.07], p = 0.01). In conclusion, CHA2DS2-VASc score accurately stratifies sACHD patients with different risk for adverse clinical events in the long term regardless of cardiac rhythm

    Physical and chemical mechanisms involved in adhesion of orthodontic bonding composites: in vitro evaluations

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    BackgroundBond strength of orthodontic composite is strongly influenced by molecular and structural mechanisms. Aim of this in vitro study was to compare bond strength of light-cure orthodontic composites by measuring debonding forces and evaluating locations of bond failure. Investigations on chemical compositions clarified adhesive behaviors and abilities, exploring effects of ageing processes in this junction materials.MethodsTwelve enamel discs, from human premolars, were randomly coupled to one orthodontic adhesive system (Transbond XT (TM) 3 M UNITEK, USA, Light-Cure Orthodontic Paste, LEONE, Italy and Bisco Ortho Bracket Paste LC, BISCO, Illinois) and underwent to Shear Bond Strength test. Metallic brackets were bonded to twenty-seven human premolar, with one of the adhesive systems, to quantify, at FE-SEM magnifications, after debonding, the residual material on enamel and bracket base surfaces. Raman Spectroscopy analysis was performed on eight discs of each composites to investigate on chemical compositions, before and after accelerated aging procedures in human saliva and sugary drink.ResultsOrthodontic adhesive systems showed similar strength of adhesion to enamel. The breakage of adhesive-adherent bond occurs in TXT at enamel-adhesive interface while in Bisco and Leone at adhesive-bracket interface. Accelerated in vitro aging demonstrated good physical-chemical stability for all composites, Bisco only, was weakly contaminated with respect to the other materials.ConclusionA similar, clinically adequate and acceptable bond strength to enamel for debonding maneuvers was recorded in all orthodontic adhesive systems under examination. No significant chemical alterations are recorded, even in highly critical situations, not altering the initial mechanical properties of materials

    Unexpected thymoma in a challenging case of hyperparathyroidism

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    We report the case of a woman with primary hyperparathyroidism suspected of mediastinal ectopic parathyroid adenoma revealed to be a thymoma. Our aim was to focus on some possible criticisms in distinguishing between ectopic parathyroid and thymus

    Desempenho e características de carcaça de bovinos F1 Pardo Suiço corte x Nelore, inteiros ou castrados em diferentes idades.

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    Foram avaliados o desempenho e as características de carcaça de 104 bovinos F1 pardo suíço corte x nelore, distribuídos, a partir do nascimento, em cinco tratamentos: castração ao nascimento, castração ao desmame, castração aos doze meses, castração aos dezoito meses e não castrados . Os animais foram criados em pastagens (perenes) cultivadas, com suplementação na primeira seca e terminação em confinamento na segunda seca. O ponto de abate foi estipulado para um mínimo de 460 quilos de peso vivo e 3 milímetros de gordura de cobertura, sendo esta medida por ultra-sonografia. Não houve diferenças entre os tratamentos (P>0,05) para ganho diário e peso vivo do nascimento aos dezoito meses de idade e durante o período de engorda em confinamento. Entretanto, animais inteiros mostraram um melhor desempenho (P<0,05) do que os castrados no período de dezoito a vinte meses de idade. Não houve influencia (P<0,05) da idade de castração sobre as características de carcaça, mas animais castrados foram superiores (P<0,05) aos animais inteiros em termos de acabamento e proporção de traseiro. Por outro lado, os inteiros apresentaram melhor rendimento de carcaça (P<0,05) que os castrados, independente da época da castração.bitstream/item/104670/1/Desempenho-e-caracteristicas-de-carcaca.pd

    Tubulin nitration in human gliomas

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    Immunohistochem. and biochem. investigations showed that significant protein nitration occurs in human gliomas, esp. in grade IV glioblastomas at the level of astrocytes and oligodendrocytes and neurons. Enhanced alpha-tubulin immunoreactivity was co-present in the same elements in the glioblastomas. Proteomic methodologies were employed to identify a nitrated protein band at 55 kDa as alpha-tubulin. Peptide mass fingerprinting procedures demonstrated that tubulin is nitrated at Tyr224 in grade IV tumor samples but is unmodified in grade I samples and in non-cancerous brain tissue. These results provide the first characterization of endogenously nitrated tubulin from human tumor samples
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