1,720,996 research outputs found
Theoretical Considerations for the Design of Magnetic Scaffolds for Bone Tumor Hyperthermia
No full textThe effectiveness and the quality of the hyperthermia treatment of bone tumors using magnetic implants can be improved. To date, several biocompatible biomaterials loaded with magnetic nanoparticles have been manufactured and characterized. However, the intrinsic parameters of the so-called magnetic scaffolds are not tuned to perform an optimum hyperthermia treatment. This work, for the firs time, deals with the theoretical modeling of bone tumor hyperthermia using magnetic scaffolds. The goal is to investigate the heating abilities of a synthetic, virtual set of potential implants. The analysis is oriented in identifying the most essential features and relevant parameters for providing unique, useful feedbacks, form an electromagnetic engineering point of view, to material scientists and clinicians
Challenging the Modeling of Magnetic Hyperthermia of Secondary Bone Tumors Using Magnetic Prosthetic Implants
No full textMagnetic biomaterials are powerful multifunctional tools in theranostic. They can be remotely controlled by an external magnetic field. When a radiofrequency field is used, the magnetic nano- or microparticles embedded in the biomaterial dissipate heat, which can be used for therapeutic purposes. Hyperthermia treatment of deep- seated tumors, such as bone cancers, can extensively benefit from the use of such class of magnetic responsive biomaterials. Therefore, in this work it is presented the numerical analysis of the hyperthermia treatment of secondary bone tumors performed using a magnetic hydroxyapatite prosthesis
Multiphysics Modeling of Magnetic Scaffolds for Biomedical Applications
No full textMagneto-responsive biomaterials can play a key role in several biomedical applications, from therapeutic to diagnostic. Despite the several efforts for synthesizing and characterizing bioceramics doped with magnetic ions or polymers loaded with magnetic nanoparticles, there is lack of mathematical and numerical models capable of filling the gap between nanomaterial science and engineering. This work reviews and propose numerical, multiphysics models for studying the use of magnetic scaffolds for the hyperthermia treatment of bone tumors and for magnetically targeted drug delivery
Improved COST 231-WI Model for Irregular Built-Up Areas
No full textThe estimation of the field levels generated by radio base stations set in urban environment is still urgent need and a relevant issue for the compliance to national regulations and for propagation concerns. This work copes with the estimation of electromagnetic field generated by UHF base stations in peculiar urban scenarios. To account for irregular geometries and to deal with the propagation in hilly town, the COST 231-Walfisch-Ikegami model is modified and rephrased in order to evaluate the path loss at distances greater than 20 meters from the base station in such peculiar urban environments. Measurements were carried out in the small urban and irregular built-up areas of Dorgali (NU), Cala Gonone (NU) and Lunamatrona (CA), Italy, to validate the model
Optimum Design of Superficial Microwave Hyperthermia Treatment
No full textMicrowave hyperthermia is focused on raising the temperature of cancerous tissues a few degrees above the norm, in order to induce cellular death within the tumor but avoiding excessive heating of normal tissues, at the same time. The success of this therapy is based on the concurrence of different physics processes tied to the electromagnetic radiation, to the fluid dynamic and to the bio-heat transfer. However, the characteristics of the tumor play an important role in the delivery of the therapy. In this work an optimum design of microwave hyperthermia treatment, from a numerical point of view, is presented, taking into account the multi-physic coupling and a blood perfusion model of a muscle tissue tumor
Development and Validation of a Finite Periodic Transmission Line Model for Body Channel Communication
No full textBody channel communication (BCC) is a data transmission technique which uses the human body as communication channel. The availability of mathematical and physical models which can cope with the channel description is an open issue in the literature. In this work, a finite periodic transmission line model to describe the human body as transmission medium is proposed. Bio-impedentiometric measurements from 1 kHz and 1 MHz are carried out to estimate model parameters. The developed model has been validated with measurements carried out with a ground-referred and low-complexity system called Live Wire. A ±3% error for communication distances ranging from 20 to 150 cm was found. This contribution proposes a distributed model which can be used as framework for the design and for enhancing the performances of body channel communication systems
Analysis of superparamagnetic scaffolds: For bone tissue engineering in static magnetic and dynamic fields
No full textBone tissue engineering has obtained valuable results using biophysical stimulation through magnetic fields to enhance integration of prosthetic implants. Recently a new class of therapeutic scaffolds has been developed in order to activate remotely, in non-invasive way, using magnetic fields. In our work we analyzed the ability of these scaffolds to attract magnetic bioagents towards them, thanks to the magnetic field gradients due to the non-linear response of the prosthetic implant. The possibility of influence osteogenic and/or angiogenic cells is taken into account, and a simple chemotaxis model indirectly driven by magnetic field is proposed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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