Autopistas de la información. Aplicación en cirugía ortopédica

El término autopistas de información describe los servicios de telecomunicaciones que estarán disponibles dentro de 10-15 años. El embrión de estas autopistas es Internet. Internet ofrece 2 clases de servicios: a) comunicación entre usuarios de todo el mundo, y b) acceso a servicios de información. En el primer grupo de estos servicios encontramos el correo electrónico y los grupos de discusión. En el segundo podemos encontrar servicios como logon remoto, transferencia de ficheros, Gopher o WWW. Describimos cada uno de estos servicios y su aplicación a la ortopedia.Information highway describes the telecomunication services will be working in the next 10-15 years. The embryo of this highway is Internet. Internet offers two kinds of services: a) communication between users around the worid, and b) access to information services. In the first group of this services we can find electronic mail and news group. In the second group we can find services such as telnet, file transfer, Gopher and World Wide Web. We describe each of this kind of services and their applications in orthopaedic surgery

Review of the “state of the art” and possibilities of the most significant approaches to the specific delivery of chemotherapy agents to tumor cells

Los principales problemas de la quimioterapia proceden esencialmente de la relativa falta de especificidad derivada de la extensa biodistribución de los agentes antitumorales y de los efectos secundarios generados por la acción inespecífica de éstos en tejidos y órganos sanos. La necesidad de encontrar tratamientos eficaces contra el cáncer ha hecho que se incrementen las líneas de investigación en esta materia. Una de las aproximaciones más prometedoras en este sentido es el desarrollo de sistemas coloidales biodegradables para el transporte de fármacos antitumorales. Gracias a éstos, se logra acumular específicamente la cantidad de fármaco administrada en el lugar de acción, logrando así un aumento significativo de la eficacia clínica, junto con una minimización de las reacciones adversas asociadas. En este trabajo, pretendemos analizar el estado actual en el diseño de coloides como transportadores de fármacos antitumorales, junto con la aplicación de las novedosas estrategias de transporte pasivo y activo de fármacos.The main problems related to chemotherapy mainly come from a relative lack of selectivity, that is associated to the extensive biodistribution of antitumor molecules, and to the severe side effects generated by the unspecific drug action on healthy tissues and organs. The need of finding out efficient treatments against cancer has led to an enhancement in the number of research lines in the field. In this way, one of the most promising approaches is the development of biodegradable colloids for the delivery of antitumor drugs. Thanks to them, it is possible to specifically concentrate the drug into the site of action. Therefore, a significant improvement of the chemotherapy effect is obtained along with a minimization of the related adverse side effects. In this review, we analyze the current “state of the art” in the development of colloidal systems for the efficient delivery of anticancer drugs. The possibilities of novel drug delivery strategies based on passive and active targeting mechanisms are also discussed

Sistemas transportadores de fármacos basados en el polímero poly(e- caprolactona) para el tratamiento del cáncer

Chemotherapy agents have little or no specificity over cancer cells, resulting in low therapeutic concentrations at the tumor site (a consequence of a broad systemic distribution), and severe side effects. With the aim of avoiding cancer therapy failure, several approaches such as design of new anticancer drugs, chemical engineering of conventional drugs and development of drug delivery systems have been proposed. The objective is to enhance drug localization at the tumor region (by controlling its biodistribution profile) and, therefore, to increase the anti-tumor efficacy (even in multi-drug resistant tumors), while reducing systemic side effects. One of the most promising approaches to the problem is the development of drug nanocarriers based on the polymer poly(e-caprolactone). In this review we will focus our attention on these polymeric colloids, particularly on the most significant characteristics and formulation procedures, and on their use as nanoplatforms for the delivery of chemotherapy agents to the tumor site. Furthermore, the most recent in vitro and in vivo investigations on the subject are extensively reviewed

Current-Driven Domain Wall Motion in Curved Ferrimagnetic Strips Above and Below the Angular Momentum Compensation

[EN] Current driven domain wall motion in curved Heavy Metal/Ferrimagnetic/Oxide multilayer strips is investigated using systematic micromagnetic simulations which account for spinorbit coupling phenomena. Domain wall velocity and characteristic relaxation times are studied as functions of the geometry, curvature and width of the strip, at and out of the angular momentum compensation. Results show that domain walls can propagate faster and without a significant distortion in such strips in contrast to their ferromagnetic counterparts. Using an artificial system based on a straight strip with an equivalent current density distribution, we can discern its influence on the wall terminal velocity, as part of a more general geometrical influence due to the curved shape. Curved and narrow ferrimagnetic strips are promising candidates for designing high speed and fast response spintronic circuitry based on current-driven domain wall motion.Projects SA114P20 and SA299P18 from Junta de Castilla y Leon (JCyL) MAT2017-87072-C4-1-P and PID2020-117024GB-C41 from the Ministry of Economy, Spanish government MAGNEFI, from the European Commission (European Union

Geometrical design for pure current-driven domain wall nucleation and shifting

[EN]Nucleation of domain walls by current-driving a single domain wall, confined to the junction area of two symmetrical strips, is investigated using systematic micromagnetic simulations. Secondary domain walls (equivalently, bits encoded in domains) are simultaneously nucleated and driven by alternatively applying current pulses between two terminals in the structure. Simulations show that nanosecond-duration current pulses nucleate and drive series of robust up/down domains even under realistic conditions. These results demonstrate a technique for sequentially nucleating and shifting domain walls without using attached external “bit lines,” fields, or modifying the ferromagnetic strip

Influence of phase-diversity image reconstruction techniques on circular polarization asymmetries

Full Stokes filter-polarimeters are key instruments for investigating the rapid evolution of magnetic structures on the solar surface. To this end, the image quality is routinely improved using a-posteriori image reconstruction methods. We analyze the robustness of circular polarization asymmetries to phase-diversity image reconstruction techniques. We use snapshots of magneto-hydrodynamical simulations carried out with different initial conditions to synthesize spectra of the magnetically sensitive Fe I line at 5250.2 A. We degrade the synthetic profiles spatially and spectrally to simulate observations with the IMaX full Stokes filter-polarimeter. We also simulate the focused/defocused pairs of images used by the phase-diversity algorithm for reconstruction and the polarimetric modulation scheme. We assume that standard optimization methods are able to infer the projection of the wavefront on the Zernike polynomials with 10% precision. We also consider the less favorable case of 25% precision. We obtain reconstructed monochromatic modulated images that are later demodulated and compared with the original maps. Although asymmetries are often difficult to define in the quiet Sun due to the complexity of the Stokes V profiles, we show how asymmetries are degraded with spatial and spectral smearing. The results indicate that, although image reconstruction techniques reduce the spatial smearing, they can modify the asymmetries of the profiles, mainly caused by the appearance of spatially-correlated noise.Comment: 10 pages, accepted for publication in A&

Optimisation of energy supply at off-grid healthcare facilities using Monte Carlo simulation

In this paper, we present a methodology for the optimisation of off-grid hybrid systems (photovoltaic-diesel-battery systems). A stochastic approach is developed by means of Monte Carlo simulation to consider the uncertainties of irradiation and load. The optimisation is economic; that is, we look for a system with a lower net present cost including installation, replacement of the components, operation and maintenance, etc. The most important variable that must be estimated is the batteries lifespan, which depends on the operating conditions (charge/discharge cycles, corrosion, state of charge, etc.). Previous works used classical methods for the estimation of batteries lifespan, which can be too optimistic in many cases, obtaining a net present cost of the system much lower than in reality. In this work, we include an advanced weighted Ah-throughput model for the lead-acid batteries, which is much more realistic. The optimisation methodology presented in this paper is applied in the optimisation of the electrical supply for an off-grid hospital located in Kalonge (Democratic Republic of the Congo). At the moment, the power supply relies on a diesel generator; batteries are used in order to ensure the basic supply of energy when the generator is unavailable (night hours). The optimisation includes the possibility of adding solar photovoltaic (PV) panels to improve the supply of electrical energy. The results show that optimal design could achieve a 28% reduction in the levelised cost of energy and a 54% reduction in the diesel fuel used in the generator, thereby reducing pollution. Furthermore, we discuss possible improvements to the telecommunications of the hospital

Methodology to calibrate the dissection properties of aorta layers from two sets of experimental measurements

Aortic dissection is a prevalent cardiovascular pathology that can have a fatal outcome. However, the mechanisms that trigger this disease and the mechanics of its progression are not fully understood. Computational models can help understand these issues, but they need a proper characterisation of the tissues. Therefore, we propose a methodology to obtain the dissection parameters of all layers in aortic tissue via the computational modelling of two different delamination tests: the peel and mixed tests. Both experimental tests have been performed in specimens of porcine aorta, where the intima-media and media-adventitia interfaces, as well as the medial layer, were dissected. These two tests have been modelled using a cohesive zone formulation for the separating interface and a hyperelastic anisotropic material model via an implicit static analysis. The dissection properties of each interface have been calibrated by reproducing the force-displacement curves obtained in the experimental tests. The values of peak and mean force of the experiments were fitted with an error below 10%. With this methodology, we intend to contribute to the development of reliable numerical tools for simulating aortic dissection and aortic aneurysm rupture. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Ac magnetic susceptibility of a molecular magnet submonolayer directly patterned onto a microSQUID sensor

We report the controlled integration, via Dip Pen Nanolithography, of monolayer dots of ferritin-based CoO nanoparticles (12 Bohr magnetons) into the most sensitive areas of a microSQUID sensor. The nearly optimum flux coupling between these nanomagnets and the microSQUID improves the achievable sensitivity by a factor 100, enabling us to measure the linear susceptibility of the molecular array down to very low temperatures (13 mK). This method opens the possibility of applying ac susceptibility experiments to characterize two-dimensional arrays of single molecule magnets within a wide range of temperatures and frequencies.Comment: 4 pages 3 figure