642 research outputs found
Biomechanically Active Hybrid nano composite for early osteointegration implants
No full textA biomimetic approach has been applied to design and realize new odontostomatological Titanium (Ti) implants using a multifunctional bioactive ceramopolymeric hybrid material. The proposed biomimetic/biomechanical approach consists in combining mechanical and physical characterization of the hybrid nanocomposite to biosolid mechanics Finite Element Analysis of the new design implants. Hybrid ceramopolymeric nanocomposites based on Hydroxyl-Ethyl-Methacrylate polymer (pHEMA) filled with nanosilica particles are presented as biomimetic-scaffolding materials. Cytotoxicity and Osteoblast cells adhesion tests have shown good material biocompatibility and osteoconductivity [1]. Dynamic Mechanical Analysis (DMA) confirmed the hybrid mechanical behaviour of these nanocomposites. Moreover, this class of material swells in presence of aqueous physiological solution according to limiting Case II sorption mode turning from glassy and rigid to soft and rubbery while presenting a mechanical behaviour, at 5 to 10 % nanosilica volume loadings, that is comparable with that of bone (when glassy) and to that of the cartilage and Ligaments (when rubbery). Materials swelling behaviour and mechanical characterizations are presented. Design criteria and FEM simulation are discussed. The use of mechanically compatible hybrid hydrogels as scaffolding materials are expected to increase prosthesis adaptation mechanisms introducing active interfaces that improve implant biomimetics while reproducing cartilage and ligaments biomechanical functions.
[1] C Schiraldi, A D'Agostino, A Oliva, ... R Aversa, M De Rosa, Biomaterials, 25 (17), 3645-3653 (2004).
[2] R Aversa, D Apicella, L Perillo, R Sorrentino, F Zarone, M Ferrari, A Apicella, Dental Materials, 25(5), 678-690 (2009).
[3] D Apicella, R Aversa, F Ferro, D Ianniello, A Apicella, J. of Biomedical Material Research: Part B, Applied Biomaterials, vol-93(1), 150-163 (2010)
Hybrid Ceramo-Polymeric Scaffolds with Biomimetic Characteristics
No full textThe research develops and tests new hybrid biomimetic materials that work as mechanically stimulating "scaffolds" to promote early regeneration in implanted bone healing phases. A biomimetic nanostructured osteoconductive material coated apparatus is presented. Bioinspired approaches to materials and templated growth of hybrid networks using self-assembled hybrid organic-inorganic interfaces is finalized to extend the use of hybrids in the medical field. Combined in vivo, in vitro and computeraided simulations have been carried out. A new experimental methodology for the identification of design criteria for new innovative prosthetic implant systems is presented. The new implant design minimizes the invasiveness of treatments while improving implant functional integration [1]. A new bioactive ceramo-polymeric hybrid material was used to modify odontostomatological Titanium implants in order to promote early fixation, biomechanical stimulation for improved scaffold mineralization and ossification. It is a hybrid ceramo-polymeric nanocomposites based on Hydroxyl-Ethyl- Methacrylate polymer (pHEMA) filled with nanosilica particles that have shown biomimetic characteristics [2,3]. This material swells in presence of aqueous physiological solution leading to the achievement of two biomechanical functions: prosthesis early fixation after and bone growth stimulation. Such multidisciplinary approach explores novel ideas in modelling, design and fabrication of new nanostructured biomaterials with enhanced functionality and improved interaction with OB cells.
[1] R Aversa, D Apicella, L Perillo, R Sorrentino, F Zarone, M Ferrari, A Apicella, Dental Materials, 25(5), 678-690 (2009).
[2] C Schiraldi, A D'Agostino, A Oliva, ... R Aversa, M De Rosa, Biomaterials, 25 (17), 3645-3653 (2004).
[3] G R. Beck, Shin-Woo Ha, C E Camalier, M Yamaguchi, Y Li, J K Lee, M. N Weitzmann, Nanomedicine, 8(6), 793-803 (2012)
Uma história do ensino primário em tempos de modernização da matemática escolar, Vassouras, 1950-1969.
No full textSALVADOR, Heloisa Hernandez de Fontes. Uma história do ensino primário em tempos de modernização, Vassouras 1950-1969, 2012, xv, 104f.: il.; 29,7cm. Dissertação (Mestrado Profissional em Educação Matemática) – Universidade Severino Sombra, Vassouras, 2012.A presente dissertação está inserida no projeto “A Matemática do Ensino Primário de Vassouras, RJ: Estudando um século de provas de alunos (1869 – 1969)”, financiado pela FAPERJ, coordenado pela professora Lúcia Maria Aversa Villela. Baseou-se no aporte teórico-metodológico da História Cultural e, como indica o título, localiza parte da história da educação matemática, em um espaço geográfico – Vassouras, cidade histórica localizada na região centro-sul fluminense – no período de 1950 a 1969. Teve como objetivo geral analisar as transformações sofridas pelo ensino da matemática no curso primário, neste espaço temporal, a partir de provas de alunos encontradas no Arquivo Público da Secretaria Municipal de Educação de Vassouras (APSMEV), sob a salvaguarda da seção do Instituto de Pesquisa Histórica do Arquivo Nacional (IPHAN). Estas fontes foram cotejadas com livros didáticos, que segundo indícios, provavelmente foram utilizados pelos professores do município nesta época, além de legislações, depoimentos orais e outros dados. A pesquisa mostra que o ensino primário de Vassouras neste período apresentava uma diversidade quanto às metodologias utilizadas, percebendo-se a presença do modelo tradicional caracterizado pelo ensino intuitivo ou lição das coisas e o ensino baseado nas experiências das crianças que tem a Escola Nova como precursora. Por estar vinculada a linha de pesquisa História da Educação Matemática do Mestrado Profissional em Educação Matemática, a presente pesquisa disponibiliza como produto um livreto - “Dividindo histórias e opiniões- Compartilhando e polemizando a operação de divisão” - que partilha “histórias” sobre a operação de divisão, encontradas nos livros didáticos analisados durante a pesquisa, além de alguns de Arithmetica do século XIX e de História da Matemática
CAG repeat testing of androgen receptor polymorphism: is this necessary for the best clinical management of hypogonadism?
No full textIntroduction It is controversial whether or not testing the length of the androgen receptor polymorphism in clinical practice is useful for correct diagnosis and treatment of hypogonadism. AimTo describe the molecular and clinical implications of testing the length of the androgen receptor polymorphism for treatment of hypogonadism in both male and female subjects. MethodsA systematic Medline search was conducted using several terms related to and including the terms androgen receptor, CAG-repeat polymorphism, male hypogonadism, female hypogonadism, and neurodegenerative disease. Main Outcome MeasuresClinical evidence that demonstrates the importance of CAG repeat number investigation in male and female hypogonadism. Results A thorough review of the clinical utility of CAG repeat polymorphism investigation in men and women with hypogonadism is presented. Conclusions The role of AR CAG repeat number investigation in hypogonadism (male and female) is not yet established in the clinical practice. In both sexes, a role during clinical management of hormonal replacement therapies may be hypothesized, but the CAG repeat number's relationship with the presence or absence of hypogonadal symptoms remains unclear. Pharmacogenomic investigations of the AR polymorphism may be a future option to tailor testosterone titration individually and to better identify subjects as potentially more or less responsive to treatments; also, investigation may be important to individually predict beneficial and side effects in special subpopulations, specifically, obese men and postmenopausal women. Francomano D, Greco EA, Lenzi A, and Aversa A. CAG repeat testing of androgen receptor polymorphism: Is this necessary for the best clinical management of hypogonadism? J Sex Med 2013;10:2373-2381
Soils of the Aversa plain (southern Italy)
No full textThe Aversa plain is one of the most important agricultural areas of the Campania region, combining the presence of very fertile soils, sites of great archaeological interest and growing residential urbanization. In this paper, the soil map (1:50,000 scale) of the Aversa plain is presented. Three main land systems (coastal, alluvial and foothill plains) characterized by different soil types (Andosols, Phaeozems, Cambisols, Vertisols, Arenosols, Histosols, Luvisols) have been identified. However, Andosols are the most widespread soil type (9768 ha) and, along with part of the Phaeozems and Cambisols, represent the most fertile soils of the Aversa plain (first and second classes of the land capability classification). In order to evaluate recent intense soil sealing, its impact over land capability classes was assessed during the last 60 years. Results show that soil sealing in the Aversa plain affected mainly the most fertile first- and second-class soils.</p
3d Analysis and Nano-indentation Mechanical Characterization of A Commercial Zr44-Ti11-Cu10-Ni10-Be25 Metal Glassy Alloy
No full textStiffness and elastic mechanical properties of the Zr44-Ti11-Cu10-Ni10-Be25 metal glass Alloy have been investigated by nano-indentation and Atomic Force Microscopy.
Continuous stiffness measurements were carried out on the as received samples. Max indentation depth of 2000 Nm has been chosen. A 3D analysis of the indent traces has been performed using a Atomic Force Microscope: pile-up at the indentation edge was observed. These metallic glasses, therefore, although showing brittle like linear elastic behaviour up to failure are still capable of undergoing plastic shear flow at the nanoscale level that may potentially lead to high material ultimate properties. Elastic modulus of 116,2 ± 0,9 GPa has been found to be independent on indentation depth while a high hardness of 8,0 ± 0,8 GPa has been measured at low indentation depths (100 nm) that progressively reduces to a constant value of 7,0 ± 0,1 GPa at increasing depths (up to 2000 nm)
Re-dosing of prostaglandin-E-1 versus prostaglandin-E-1 plus phentolamine in male erectile dysfunction: a dynamic color power Doppler study - Reply to HC Porst
No full textOsmotic Tension, Plasticization and Viscoelastic response of amorphous Poly-Ether-Ether-Ketone (PEEK) equilibrated in humid environments
No full textDynamic-Mechanical Analysis (DMA), Differential scanning Calorimetry (DSC) and water moisture sorption-desorption kinetics and equilibria have been parallely investigated to monitoring the environmental and thermal sensitivity of amorphous thermoplastic Poly-Ether-Ether-Ketone (PEEK). Morphological modification occurring in PEEK during the calorimetric and thermo-mechanical characterizations and the hygrothermal stability are presented. An interpretation based on the free energy of mixing of a polymer chains with penetrant molecules and pseudo-equilibrium Flory-Huggins interaction parameter ? and related osmotic tension is proposed. The correlation between dynamic mechanical measurements and water saturation is discussed in terms of different levels of osmotic tension generated in the amorphous PEEK. From the analysis of the water diffusion coefficients in amorphous PEEK equilibrated at low and high activity environments, it has been found that even samples with very low water contents may undergo bulk matrix relaxation above 40°C
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