Evaluación del impacto del “Precondicionamiento regenerativo” en el perfil molecular y energético del síndrome de “Small-For-Flow” en un modelo porcino

Actualmente, los límites de resección en la cirugía hepática están establecidos por la posibilidad de desarrollar insuficiencia hepática posthepatectomía. Esto impide en ocasiones, intervenir a pacientes para los que la cirugía hepática es el único tratamiento potencialmente curativo, como es el caso de numerosos pacientes con metástasis hepáticas de cáncer colorrectal. Y es por eso, que conseguir un volumen hepático remanente suficiente para mantener la función hepática, es en nuestros días, uno de los temas más relevantes en el ámbito de la cirugía hepatobiliar. Por otro lado, a día de hoy, se llevan a cabo de rutina, distintas estrategias para aumentar el volumen del futuro remanente como la embolización portal o la hepatectomía en dos tiempos. Nuestro grupo evalúa una estrategia diferente, el “Precondicionamiento regenerativo”, que se basa en aplicar un estímulo regenerativo antes de la resección hepática. Se trata de una técnica de estimulación de la regeneración hepatocitaria, que consiste en realizar una ligadura o embolización portal del área de parénquima hepático que va a ser resecado, seguida de una hepatectomía precoz, entre 1 y 4 días después. A diferencia de la técnica clásica, que espera unas 4 semanas, no buscamos un aumento del volumen del remanente hepático sino un aumento de su tolerancia a la resección..

Optimising piezoelectric and magnetoelectric responses on CoFe2O4/P(VDF-TrFE) nanocomposites

Magnetoelectric nanocomposite films composed of magnetostrictive CoFe2O4 nanoparticles with sizes between 35 and 55 nm embedded in P(VDF-TrFE) have been successfully prepared by a solvent casting method. The ferroelectric, piezoelectric, magnetic and magnetoelectric properties of the nanocomposite and their variation with the wt% of the ferrite filler, thickness of the composite and direction of the applied magnetic field have been investigated. Ferroelectric and piezoelectric properties are improved when small amount of ferrite nanoparticles were added to the polymeric matrix. Magnetic properties vary linearity with ferrite content. The highest magnetoelectric response of 41.3 mV/cmOe was found in the composite with 72wt% when a 2.5 kOe DC field was transversely applied to the sample surface. This value is among the highest reported in two phase particulate polymer nanocomposites. Thickness of the composite has no influence in the magnetoelectric response, allowing tailoring sensor thickness for specific applications. The good value of the magnetoelectric coefficient and the flexibility of the films make these composites suitable for applications in magnetoelectric smart devices.Fundação para a Ciência e a Tecnologia (FCT) (PTDC/CTM/69316/2006), (SFRH/BD/45265/2008).FEDER “Programa Operacional Factores de Competitividade – COMPETE” (NANO/NMed-SD/0156/2007)Basque Government Industry Department - Project Actimat (ETORTEK-IE10-272)COST Action MP1003, 2010 - The „European Scientific Network for Artificial Muscles‟ (ESNAM)

Induced magnetic anisotropy features in FeCrSiBNbCu nanocrystalline alloy: Role of stress distribution proven by direct X-ray measurements

Fe73.5-xCrxSi13.5B9Nb 3Cu1 (x = 1, 2, and 3) amorphous ribbons were prepared by single roller rapid quenching technique. Both conventional and stress annealing at 520 C for 2 h at the value of the specific load of 150 MPa resulted in the formation of a nanocrystalline structure with average grain size about 13 nm. No significant differences in crystallite size were observed for all samples under consideration. The crystallite orientations were practically isotropic indicating no texture in the samples of all types. For all conventionally annealed ribbons a longitudinal effective magnetic anisotropy with an easy magnetization axis parallel to the ribbon axis was observed. For all stress annealed ribbons a transverse induced magnetic anisotropy with the anisotropy constant value of about 1800 ± 50 J/m3 was evident. Induced magnetic anisotropy features in FeCrSiBNbCu nanocrystalline alloy, namely an importance of the stress distribution was proven by direct X-ray measurements. A very good correlation between the induced magnetic anisotropy constant values and anisotropic stress distribution was observed. © 2013 Elsevier B.V. All rights reserved

Surface modified Ni nanoparticles produced by the electrical explosion of wire

Spherical nickel nanoparticles were prepared by the electrical explosion of wire. The as prepared nanoparticles were modified immediately after fabrication at room temperature in order to provide tunable surface properties with focus on the development of composites filled with nanoparticles. Following liquid modificators were used: hexane, toluene and the solution of polystyrene in toluene. In one case the surface modification by carbon was made in gas phase as a result of hydrocarbon injection. The average size of the nanoparticles was about 50 nm and unit cell parameters were close to 0.351 nm. Detailed characterization was done by X-ray diffraction, transmission electron microscopy, and magnetization measurements. Sphericity was also checked using microwave resonant absorption. © (2015) Trans Tech Publications, Switzerland.Electromagnetics of Russian Academy of Sciences;et al;Institute for Theoretical and Applied;Japan Society for the Promotion of Science;Lomonosov Moscow State University;Russian Foundation for Basic Researc

Magnetic behavior of metastable fcc Fe-Cu after thermal treatments

A ferromagnetic and supersaturated fcc Fe_51Cu_49 solid solution has been obtained by mechanical alloying. After subsequent thermal treatments the fcc phase undergoes a spinodal decomposition which finally, at 780 K, yields a mixture of fcc and bcc phases. In this work, a systematic magnetic study is carried out on samples at diferent decomposition states in order to determine the process of transformation into the stable phases. We observe a 20% maximum diminution on the magnetic moment with increasing temperatures of the thermal treatment. The Mössbauer spectrum taken at 8 K shows that 20% of the Fe atoms are in a nonferromagnetic state. On the other hand, upon heating up to 723 K the roomtemperature coercive field increases dramatically to 640 Oe, and after cooling down to 10 K it decreases to 270 Oe. Deviations from the T law in the temperature dependence of the magnetization have been observed. This behavior is explained by fluctuations in composition due to the spinodal decomposition, which lead to fluctuations of the magnetic order parameters, i.e., magnetic moment and Curie temperature

Crossover from superspin glass to superferromagnet in FexAg100-x nanostructured thin films ( 20 ≤ x ≤ 50 )

FexAg100?x granular thin films, with 20 x 50, have been prepared by the dc-magnetron sputtering deposition technique. With this technique we have been able to obtain samples comprising small Fe nanoparticles 2.5?3 nm embedded in a Ag matrix, remaining their size practically constant with increasing Fe content. Their magnetic behavior has been fully characterized by dc magnetic measurements between 5?350 K. They have revealed a crossover in the collective magnetic behavior of the Fe nanoparticles around a 35 at. %. Below such a concentration, a collective freezing of the magnetic moments is observed at low temperatures, while at high temperatures a transition, mainly mediated by dipolar interactions, to a magnetically disordered state is obtained. Above this concentration, direct exchange interactions overcome the dipolar magnetic interactions and a long-range order tends to prevail in the range of temperatures analyzed. ac magnetic measurements have indicated a crossover from a superspin glass x35 to a superferromagnetic x35 behavior for the magnetic moments of the Fe nanoparticles.This work was supported by the CICYT of Spain under Contracts No. MAT2008-06542-C04-02 and No. MAT2008- 06542-C04-04. SGIker technical support MEC, GV/EJ, European Social Fund is gratefully acknowledged. The financial support from the Basque Government Department of Education Project No. IT-347-07 is acknowledged

Assemblies of magnetite nanoparticles extracted from magnetotactic bacteria: A magnetic study

Self-assembly has emerged as a suitable technique for tuning the properties of nanoparticles. In this work, we report the self-assembly of magnetosomes assisted by an external magnetic field. The magnetosomes are magnetite nanoparticles biomineralized by magnetotactic bacteria Magnetospirillum gryphiswaldense. These nanoparticles present truncated cubo-octahedral morphology with a mean diameter of ˜36 nm and are surrounded by a lipid bilayer membrane with a thickness ˜2-4 nm. The use of the appropriate preparation conditions, such as initial colloidal concentration and magnetic fields applied during deposition allowed us to obtain very reproducible self-assembled 2D patterns. Homogeneous ensembles of magnetosomes onto silicon and carbon surfaces are composed of elongated structures in the form of wide chains that cover a large area of the substrates. Transmission electron microscopy image and off-axis electron holography showed the map of the stray magnetic fields produced by these assemblies. The induced magnetic anisotropy was analyzed by measuring the hysteresis loops of the assemblies at different angles in a magneto-optical Kerr effect magnetometer. The evolution of the coercive field and remanence verified the presence of well-defined patterns. The experimental results were analyzed on the based of a biaxial model

EVALUACIÓN DEL CONOCIMIENTO ENFERMERO EN EL MANEJO AL PACIENTE NEUTROPÉNICO

Objective: To evaluate the nursing staff's knowledge about management of cancer patients with febrile neutropenia. Methodology: An observational descriptive study was carried out with 35 nurses of hospital centers in Havana city, from 2006 to 2008. A structured survey was designed and then applied, with previous consent, to the participating nurses. Results: Out of 35 nurses interviewed, 51.4% have their degree, 54.4% work in institutes, 57.1% perform assistance functions and 37.7% work in oncohematologic services. Work experience in this service is between one and two years. 68.5% of nurses know a lot about neutropenia, 25.7 % know a little, and 5.7 % do not know anything about the topic. Conclusions: The knowledge level was high in the majority, and it was associated with the precedent of having received postgraduate courses regarding Oncology and training from the nurses in the units where they work.Objetivo: Evaluar el conocimiento del personal de enfermería sobre el manejo del paciente oncológico con neutropenia febril. Método: Estudio observacional descriptivo evaluativo con 35 enfermeros pertenecientes a centros hospitalarios de Ciudad de la Habana durante el período 2006 -2008. Se diseño un cuestionario estructurado que fue aplicado con previo consentimiento de los enfermeros participantes. Resultados: De los 35 enfermeros encuestados, el 51.4% son licenciados, 54.4% trabajan en institutos, el 57.1% ejercen funciones asistenciales, y el 37.7% laboran en servicios oncohematologicos. Los años de experiencia de trabajo en el servicio oscilan entre 1 y 2 años. El 68.5% posee mucho conocimiento sobre neutropenia, poco un 25.7% y no tienen conocimientos el 5.7%. Conclusiones: El nivel de conocimiento fue evaluado en su mayoría de mucho, y se asoció al antecedente de haber recibido cursos postgrados sobre Oncología y adiestramientos de los enfermeros en los servicios donde laboran