Las perspectivas de corrección de errores oral de profesores y alumnos del inglés iraníes: ¿importa la línea de tiempo de la corrección?

Although the provision of error correction is commonly utilized in education, there are controversies regarding ‘when’ correction is most effective and why it is effective. This study investigated the differences between Iranian EFL teachers and learners regarding their perspectives towards the timeline of error correction in the speaking skill. Two main categories of immediate and delayed feedback types were determined with the immediate category specifically referring to ‘very soon’ and ‘after speaking’ and the delayed one relating to ‘after activities’ and ‘end of class’ sub-categories. To empirically test the hypothesis behind the study, a total of 460 teachers and learners were invited to complete Fukuda’s questionnaire. The obtained data were analyzed through MANOVA, the results of which showed teachers’ preferences towards the immediate correction and the learners’ inclination towards the delayed correction. Based on the results, specific properties and circumstances in relation to the timing of feedback were proposed to enhance its efficiency in L2 classrooms.Aunque la prestación de corrección de errores es común en la educación, existen controversias en cuanto a ‘cuándo’ la corrección es más eficaz y por qué es eficaz. Este estudio investigó las diferencias entre profesores y alumnos del inglés como lengua extranjera(EFL) iraníes con respecto a sus perspectivas hacia la línea de tiempo de la corrección de errores en la habilidad de hablar. Se determinaron 2 categorías principales de tipos de retroalimentación, inmediatos y retardados, con la categoría inmediata refiriéndose específicamente a ‘muy pronto’ y ‘después de hablar’ y la retardada en relación con las sub-categorías ‘después de las actividades’ y ‘al final de la clase’. Para probar empíricamente la hipótesis detrás del estudio, se invitaron a un total de 460 profesores y alumnos para completar el cuestionario de Fukuda. Los datos obtenidos fueron analizados mediante un análisis multivariado de varianza (MANOVA), cuyos resultados mostraron las preferencias de los profesores para la corrección inmediata, mientras que los estudiantes se inclinan hacia la corrección retardada. Con base en estos resultados, se proponen las propiedades y las circunstancias específicas en relación con el momento de la retroalimentación para mejorar su eficiencia en las aulas de idiomas

Influence of sex hormones on the periodontium

Objectives : Sex hormones have long been considered to play an influential role on periodontal tissues, bone turnover rate, wound healing and periodontal disease progression. The objectives of this review article are to (1) address the link between sex hormones and the periodontium, (2) analyse how these hormones influence the periodontium at different life times and (3) discuss the effects of hormone supplements/replacement on the periodontium. Materials and Methods : Two autonomous searches were performed in English language utilizing Medline, Premedline and Pubmed as the online databases. Publications up to 2002 were selected and further reviewed. In addition, a manual search was also performed including specific related journals and books. Results : It is certain that sexual hormones play a key role in periodontal disease progression and wound healing. More specifically, these effects seem to differentiate by gender as well as lifetime period. In addition, the influence of sex hormones can be minimized with good plaque control and with hormone replacement. Conclusion : Despite profound research linking periodontal condition with sex hormones kinetics, more definitive molecular mechanisms and therapy still remain to be determined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75598/1/j.1600-051X.2003.00055.x.pd

Activator protein-1 (AP-1) signalling in human atherosclerosis: results of a systematic evaluation and intervention study

Animal studies implicate the AP-1 (activator protein-1) pro-inflammatory pathway as a promising target in the treatment of atherosclerotic disease. It is, however, unclear whether these observations apply to human atherosclerosis. Therefore we evaluated the profile of AP-1 activation through histological analysis and tested the potential benefit of AP-1 inhibition in a clinical trial. AP-1 activation was quantified by phospho-c-Jun nuclear translocation (immunohistochemistry) on a biobank of aortic wall samples from organ donors. The effect of AP-1 inhibition on vascular parameters was tested through a double blind placebo-controlled cross-over study of 28 days doxycycline or placebo in patients with symptomatic peripheral artery disease. Vascular function was assessed by brachial dilation as well as by plasma samples analysed for hs-CRP (high-sensitivity C-reactive protein), IL-6 (interleukin-6), IL-8, ICAM-1 (intercellular adhesion molecule-1), vWF (von Willebrand factor), MCP-1 (monocyte chemoattractant protein-1), PAI-1 (plasminogen activator inhibitor-1) and fibrinogen. Histological evaluation of human atherosclerosis showed minimal AP-1 activation in non-diseased arterial wall (i.e. vessel wall without any signs of atherosclerotic disease). A gradual increase of AP-1 activation was found in non-progressive and progressive phases of atherosclerosis respectively (P<0.044). No significant difference was found between progressive and vulnerable lesions. The expression of phospho-c-Jun diminished as the lesion stabilized (P<0.016) and does not significantly differ from the normal aortic wall (P<0.33). Evaluation of the doxycycline intervention only revealed a borderline-significant reduction of circulating hs-CRP levels (−0.51 μg/ml, P=0.05) and did not affect any of the other markers of systemic inflammation and vascular function. Our studies do not characterize AP-1 as a therapeutic target for progressive human atherosclerotic disease

In Vitro Antioxidant, Anticoagulant and Antimicrobial Activity and in Inhibition of Cancer Cell Proliferation by Xylan Extracted from Corn Cobs

Xylan is one of most abundant polymer after cellulose. However, its potential has yet to be completely recognized. Corn cobs contain a considerable reservoir of xylan. The aim of this work was to study some of the biological activities of xylan obtained from corn cobs after alkaline extraction enhanced by ultrasonication. Physical chemistry and infrared analyses showed 130 kDa heteroxylan containing mainly xylose:arabinose: galactose:glucose (5.0:1.5:2.0:1.2). Xylan obtained exhibited total antioxidant activity corresponding to 48.5 mg of ascorbic acid equivalent/g of xylan. Furthermore, xylan displayed high ferric chelating activity (70%) at 2 mg/mL. Xylan also showed anticoagulant activity in aPTT test. In antimicrobial assay, the polysaccharide significantly inhibited bacterial growth of Klebsiella pneumoniae. In a test with normal and tumor human cells, after 72 h, only HeLa tumor cell proliferation was inhibited (p < 0.05) in a dose-dependent manner by xylan, reaching saturation at around 2 mg/mL, whereas 3T3 normal cell proliferation was not affected. The results suggest that it has potential clinical applications as antioxidant, anticoagulant, antimicrobial and antiproliferative compounds

Oxidative Stress Induced Mechanisms in the Progression of Periodontal Diseases and Cancer: A Common Approach to Redox Homeostasis?

There is documented evidence of significant associations between cancer of the lung, kidney, pancreas, hematological and oral cancers and periodontal diseases of the supporting structures of the teeth. Enhanced lipid peroxidation, raised levels of TBARS and the oxidative stress marker malondealdehyde have been detected in breast cancer with reduced antioxidant capacity, also characteristic of periodontal diseases. Antioxidants could overcome this deficit and attenuate disease progression by down regulating glutathione detoxification/redox buffering system and inhibiting key transcription factors. Periodontal disease may be a critical marker of a susceptible immune system, or initiate cancer risk with a pro-oxidant inflammatory profile