4,417 research outputs found

    A Tissue Engineering product development pathway

    Get PDF
    Tissue engineering is a field of inquiry and research that uses engineering techniques and principles of biological sciences to develop functional substitutes for reconstruction of damaged organs. Commercial translation of tissue engineering products is currently in progress all over the world. Many companies are moving their interest towards this market segment that grows by 6% per year. Aim of this thesis is to probe the possibility of developing tissue engineering products in the most cost-effective way, minimizing the industrial risk and developing a specific fund raising model. Tissue engineering is based on three main features: cells, scaffolds and bioreactors. Cells are seeded on a scaffold and cultured in a bioreactor in order to obtain a tissue engineering product. Nevertheless, developing cell carrying products is hampered by certification claims ("advanced therapies" certification rules) that unbearably increase R&D and certification costs and can be faced by either big companies or start-ups of big companies and spin-offs of complex aggregates of research centers involved in advanced cell research. On the other hand, scaffolds (certification class IIb) and bioreactors for tissue engineering (certification class I) can be developed with a lower economic effort, being the competition based on innovation, since their market is in the "growth phase" for scaffolds and in the "introduction phase" for bioreactors in the Levitt's product life cycle theory. Purpose of this thesis is to basically study scaffold and bioreactor features, then to preliminarily design some models of bioreactors and, eventually, to set a business model, based on private and public fund raising, aimed to the development of scaffolds for dental implantology and of bioreactors for cardiovascular and bone tissue engineering. Finally, a business plan of a company being spin-off of Politecnico di Torino and industrial start-up has been elaborate

    Wavelet/shearlet hybridized neural networks for biomedical image restoration

    Get PDF
    Recently, new programming paradigms have emerged that combine parallelism and numerical computations with algorithmic differentiation. This approach allows for the hybridization of neural network techniques for inverse imaging problems with more traditional methods such as wavelet-based sparsity modelling techniques. The benefits are twofold: on the one hand traditional methods with well-known properties can be integrated in neural networks, either as separate layers or tightly integrated in the network, on the other hand, parameters in traditional methods can be trained end-to-end from datasets in a neural network "fashion" (e.g., using Adagrad or Adam optimizers). In this paper, we explore these hybrid neural networks in the context of shearlet-based regularization for the purpose of biomedical image restoration. Due to the reduced number of parameters, this approach seems a promising strategy especially when dealing with small training data sets

    A Surface Admittance Equivalence Principle for Non-Radiating and Cloaking Problems

    Full text link
    In this paper, we address non-radiating and cloaking problems exploiting the surface equivalence principle, by imposing at any arbitrary boundary the control of the admittance discontinuity between the overall object (with or without cloak) and the background. After a rigorous demonstration, we apply this model to a non-radiating problem, appealing for anapole modes and metamolecules modeling, and to a cloaking problem, appealing for non-Foster metasurface design. A straightforward analytical condition is obtained for controlling the scattering of a dielectric object over a surface boundary of interest. Previous quasi-static results are confirmed and a general closed-form solution beyond the subwavelength regime is provided. In addition, this formulation can be extended to other wave phenomena once the proper admittance function is defined (thermal, acoustics, elastomechanics, etc.).Comment: 7 page

    Closed-form Harmonic Contrast Control with Surface Impedance Coatings for Conductive Objects

    Full text link
    The problem of suppressing the scattering from conductive objects is addressed in terms of harmonic contrast reduction. A unique compact closed-form solution for a surface impedance Zs(m,kr)Z_s(m,kr) is found in a straightforward manner and without any approximation as a function of the harmonic index mm (scattering mode to suppress) and of the frequency regime krkr (product of wavenumber kk and radius rr of the cloaked system) at any frequency regime. In the quasi-static limit, mantle cloaking is obtained as a particular case for kr1kr \ll 1 and m=0m=0. In addition, beyond quasi-static regime, impedance coatings for a selected dominant harmonic wave can be designed with proper dispersive behaviour, resulting in improved reduction levels and harmonic filtering capability.Comment: 6 page

    Prospection and Evaluation of (Hemi) Cellulolytic Enzymes Using Untreated and Pretreated Biomasses in Two Argentinean Native Termites

    Get PDF
    Saccharum officinarum bagasse (common name: sugarcane bagasse) and Pennisetum purpureum (also known as Napier grass) are among the most promising feedstocks for bioethanol production in Argentina and Brazil. In this study, both biomasses were assessed before and after acid pretreatment and following hydrolysis with Nasutitermes aquilinus andCortaritermes fulviceps termite gut digestome. The chemical composition analysis of the biomasses after diluted acid pretreatment showed that the hemicellulose fraction was partially removed. The (hemi) cellulolytic activities were evaluated in bacterial culture supernatantsof termite gut homogenates grown in treated and untreated biomasses. In all cases, we detected significantly higher endoglucanase and xylanase activities using pretreated biomasses compared to untreated biomasses, carboxymethylcellulose and xylan. Several protein bands with (hemi) cellulolytic activity were detected in zymograms and two-dimensionalgel electrophoresis. Some proteins of these bands or spots were identified as xylanolytic peptides by mass spectrometry. Finally, the diversity of cultured cellulolytic bacterial endosymbionts associated to both Argentinean native termite species was analyzed. This study describes, for the first time, bacterial endosymbionts and endogenous (hemi) cellulases of two Argentinean native termites as well as their potential application in degradation of lignocellulosic biomass for bioethanol production.Fil: Ben Guerrero, Emiliano. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; ArgentinaFil: Arneodo Larochette, Joel Demián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Bombarda Campanha, Raquel. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Oliveira, Patrícia Abrão de. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Labate, Mônica T. Veneziano. Universidade de Sao Paulo; BrasilFil: Cataldi, Thaís Regiani. Universidade de Sao Paulo; BrasilFil: Campos, Eleonora. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cataldi, Ángel Adrián. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Labate, Carlos A.. Universidade de Sao Paulo; BrasilFil: Rodrigues, Clenilson Martins. Ministerio da Agricultura Pecuaria e Abastecimento de Brasil. Empresa Brasileira de Pesquisa Agropecuaria; BrasilFil: Talia, Paola Monica. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
    corecore