Detection of IL28B SNP DNA from Buccal Epithelial Cells, Small Amounts of Serum, and Dried Blood Spots

Background & Aims: Point mutations in the coding region of the interleukin 28 gene (rs12979860) have recently been identified for predicting the outcome of treatment of hepatitis C virus infection. This polymorphism detection was based on whole blood DNA extraction. Alternatively, DNA for genetic diagnosis has been derived from buccal epithelial cells (BEC), dried blood spots (DBS), and genomic DNA from serum. The aim of the study was to investigate the reliability and accuracy of alternative routes of testing for single nucleotide polymorphism allele rs12979860CC. Methods: Blood, plasma, and sera samples from 200 patients were extracted (400 mL). Buccal smears were tested using an FTA card. To simulate postal delay, we tested the influence of storage at ambient temperature on the different sources of DNA at five time points (baseline, 48 h, 6 days, 9 days, and 12 days) Results: There was 100 % concordance between blood, plasma, sera, and BEC, validating the use of DNA extracted from BEC collected on cytology brushes for genetic testing. Genetic variations in HPTR1 gene were detected using smear technique in blood smear (3620 copies) as well as in buccal smears (5870 copies). These results are similar to those for whole blood diluted at 1/10. A minimum of 0.04 mL, 4 mL, and 40 mL was necessary to obtain exploitable results respectively for whole blood, sera, and plasma. No significant variation between each time point was observed for the different sources of DNA. IL28B SNPs analysis at these different time points showed the same results using the four sources of DNA

Towards the development of a numerical code for the simulation of aircraft braking

Atti del Dipartimento di Ingegneria Aerospaziale dell’Università di Pisa

Models and methods for the study of the in-plane transient responses of tyres

Atti del Dipartimento di Ingegneria Aerospaziale dell'Università di Pis

CARATTERIZZAZIONE SPERIMENTALE DELLE ZONE DI RINFORZO INTORNO A GRANDI APERTURE DI FUSOLIERA" Collaborazione di ricerca fra il Dipartimento di Ingegneria Aerospaziale e la Alenia Aeronautica.

Documenti del Dipartimento di Ingegneria Aerospaziale DDIA 2006-22, Novembre 200

Development of analytical methods for fuselage design: validation by means of Finite Element analyses

The paper presents the results of a set of finite element analyses (FEAs) carried out to support the development of an integrated design procedure that, based on semi-empirical and analytical methods, is capable of defining generic fuselage sections of a transport aircraft. The procedure, which is implemented in a structural optimization code, defines a structure that, compliant with durability and damage tolerance requirements, is characterized by a post-critical behaviour of the stiffened panels and by a design of the frames that takes the frame flexibility and the presence of the floor beams into account. FEAs, carried out on a reference configuration defined by the optimization code, are used to acquire a deeper knowledge of the advantages and disadvantages of the analytical approach in the design of complex structures subjected to realistic load cases. In particular, the influence of the actual frame flexibility on the distribution of the skin shear flow induced by the frame is evaluated; moreover, the effects on the stress distribution in skin and frames, caused by the presence of the stringers, and of the stiffness concentration introduced by the floor beam are addressed. Finite element method results demonstrate the effectiveness of the analytical model of the flexible frame in evaluating the shear flow that a single loaded frame transfers to the skin and highlight the effects of the presence of adjacent loaded frames. By means of geometrically non-linear FEAs, the effects of the stringers on the stress distribution of a pressurized cylinder are evaluated, as well as the magnitude and extension of the perturbation introduced by the floor beams

Modelli e metodi per lo studio della dinamica longitudinale del pneumatico

Atti del Dipartimento di Ingegneria Aerospaziale dell'Università di Pis

Effects of different models of tire and brake on the longitudinal dynamics of aircraft landing gear

The poles of a longitudinally elastic landing gear are determined with reference to different braking conditions and using different models of tire and brake. The model of the brake accounts for the effect of wheel angular velocity on the braking torque. The wheel is firstly treated as a rigid body, then the elasticity of the tire is taken into account together with the effects of tire-runway contact dynamics. Analyses of simpler models are carried out analytically, while, for more complex ones, results of a numerical investigation are presented

A three-dimensional damage model to simulate the progressive failure of composite structures

A three-dimensional damage model has been developed to simulate the progressive failure of thin composite structures. Both intralaminar and interlaminar damage mechanisms have been considered and the proposed constitutive model has been developed on the basis of thermomechanics of the nonlinear irreversible physical process. The intralaminar damage modes has been analysed in the context of the Continuum Damage Mechanics, whereas the interlaminar damage mode has been analysed by means of the Cohesive Zone Model. The objectivity of the numerical discretization has been assured using the smeared crack formulation. The proposed damage model has been benchmarked by means of an experimental low-velocity impact test taken from the Literature, reproducing the main damage mechanisms, i.e. fibre breakage, fibre kinking, matrix cracking, matrix crushing and delaminations