Improved wear performance of ultra high molecular weight polyethylene coated with hydrogenated diamond like carbon

Hydrogenated diamond like carbon (DLCH) thin films were deposited on medical grade ultra high molecular weight polyethylene (UHMWPE) by radio frequency plasma enhanced chemical vapor deposition. The DLCH coating thicknesses ranged from 250 to 700. nm. The substrates were disks made of UHMWPEs typically used for soft components in artificial joints, namely virgin GUR 1050 and highly crosslinked (gamma irradiated in air to 100. kGy) UHMWPEs. Mechanical and tribological properties under bovine serum lubrication at body temperature were assessed on coated and uncoated polyethylenes by means of nano-hardness and ball-on-disk tests, respectively. Morphological features of the worn surfaces were obtained by confocal microscopy and scanning electron microscopy. This study confirms an increase in surface hardness and good wear resistance for coated materials after 24. h of sliding test compared to uncoated polyethylene. These results point out that to coat UHMWPE with DLCH films could be a potential method to reduce backside wear in total hip and knee arthroplasties.Ministerio de Ciencia y Educación MAT2006-12603- C02-01, CSD2008-0002

Calcificaciones heterotópicas en cirugía protésica de cadera: Prótesis bicénctricas vs híbridas

Realizamos el seguimiento clínico y radiológico de 202 pacientes a los que se implantó una Prótesis Total de Cadera cementada (PTC). Analizamos la presencia de calcificaciones heterotópicas (CH) y su graduación, estudiando separadamente prótesis híbridas y bicéntricas. Valoramos los factores de riesgo relacionados con la aparición de CH, tamaño de implantes, alineación final, lado intervenido y relación con la presencia de complicaciones locales y sistemáticas. La prevalencia de CH fue de 35.5% (grado I, 19%; grado II, 10%; grado III, 5% y grado IV 1,5%); 9,9 % sintomáticas. Una mayor proporción de CH fue observada en varones (p=0,005); vástagos de mayor tamaño (p=0,001). No existen diferencias significativas (p=0,059) entre pacientes con prótesis híbridas frente a aquellos con prótesis bicéntricas. La valoración de Harris mostró diferencias en el seguimiento del parámetro dolor a los 24 meses entre los grupos con y sin CH.The clinical and radiological follow-up of 202 patients with a cemented Hip Artrhoplasty (HA) was reviewed. The presence of periarticular heterotopic ossifications (PHO) and its gradation was compared i9n hybrid and bipolar arthroplasties. Risk factors related to the appearance of PHO, implants size, final alignment, operated side and relationship to the postoperative local and systemic complications were several of the parameter analyzed. The presence of PHO was 35,5% (degree I, 19%; degree II, 10%; degree III, 5% and degree IV, 1,5%); 9,9% symptomatic. A greater proportion of PHO was observed in males (p=0,005) greater zie stems (p=0,001) and patients with postoperative local complications (p=0,001). There were no statistical differences between patients with hybrid hip arthoplasties as compared to those with bipolar his arthroplasties. The Harris score showed differences as regards pain at 24 months follow-up between the groups whit an without PHO

Coenzyme Q10 in the treatment of mitochondrial disease

Currently, there is a paucity of available treatment strategies for oxidative phosphorylation disorders. Coenzyme Q10 (CoQ10) and related synthetic quinones are the only agents to date that have proven to be beneficial in the treatment of these heterogeneous disorders. The therapeutic efficacy of CoQ10 is not restricted to patients with an underlying CoQ10 deficiency and is thought to result from its ability to restore electron flow in the mitochondrial respiratory chain (MRC) as well as to increase the cellular antioxidant capacity. At present, however, there is no consensus on the appropriate dosage or therapeutic plasma level of CoQ10, and this information will be required before CoQ10 can be utilized effectively in the treatment of mitochondrial disease. The following review will outline our current knowledge on the use of CoQ10 in the treatment of MRC disorders and primary CoQ10 deficiencies. Keyword

Simple and analytical function for the Stark profile of the Hα line and its application to plasma characterization

The increasing application of plasma based technologies over a wide range of fields has led to the necessity of an optimal determination of the characteristic parameters of the plasma systems. Optical Emission Spectroscopy techniques have been proved as an excellent tool to that end. These techniques are based on the collection and analysis of the radiation coming from the plasma, being classified between molecular and atomic emission. Among atomic emission lines, Hydrogen Balmer series lines are the most measured. The Hβ line is usually the most employed one for plasma diagnosis but under some conditions, the Hβ line is not always detectable and only the Hα line can be detected. For these lines, it is well known that their shapes are the result of the convolution of three profile types: Lorentzians, Gaussians and Starks. But while the first two types present analytical functions, models explaining the Stark profile do not offer these. So, in this paper we propose an accurate analytical function for the Stark profile of the Hα line allowing improving the determination of characteristic parameters of plasma with respect to the methods traditionally used

A simple and accurate analytical model of the Stark profile and its application to plasma characterization

Optical Emission Spectroscopy techniques are among the most employed to perform the characterization of laboratory plasmas. The analysis of the obtained data is based on the convolution of three different types of profiles: Lorentzians, Gaussians and Starks. While analytic expressions are available for the first two types, the Stark profile has been traditionally obtained through theoretical calculations using different models. In this paper, we propose is a simple and accurate analytical function that can be employed as approximation of a Stark profile. The application of this new model may simplify the analysis of plasmas

Vástago femoral PMC en cirugía protésica de cadera: revisión clínica y radiológica

Evaluamos los resultados clínicos y radiológicos de nuestros 100 primeros casos consecutivos de sustitución protésica de cadera mediante modelo de vástago cementado PMC, realizando un seguimiento mínimo de 30 meses. La media de edad de los pacientes intervenidos ha sido de 75 años. El diagnóstico en 31 de los casos fue de coxartrosis, 63 fracturas y 6 otros. El 94% de los pacientes fueron intervenidos por abordaje posterolateral. La puntuación según la escala de Harris modificada fue de 82 puntos, 92 para las prótesis híbridas y 72 para las bicéntricas. Los hallazgos clinicorradiológicos sólo mostraron el aflojamiento de 1 vastago en la serie; no encontramos alteraciones en la interfaz cemento-prótesis.We reviewed 100 consecutive hip arthroplasties with a cemented femoral component (PMC) after 30 months of follow-up. The average age of patients was 75 years. The diagnosis was osteoarthritis in 31 hips, fractures in 63 hips and others in 6. 94% hip arthroplasties were performed through the posterolateral approach. The mean Harris score at latest 30-month follow- up, was 82 points, 92 points in hybrid arthroplasties and 72 in bipolar arthroplasties. Radiographic and clinic follow-up had showed loosening of 1 stem, without abnormalities in the interface cement-prosthesis

Surface nanostructuring of TiO2 thin films by ion beam irradiation

This work reports a procedure to modify the surface nanostructure of TiO2 anatase thin films through ion beam irradiation with energies in the keV range. Irradiation with N+ ions leads to the formation of a layer with voids at a depth similar to the ion-projected range. By setting the ion-projected range a few tens of nanometers below the surface of the film, well-ordered nanorods appear aligned with the angle of incidence of the ion beam. Slightly different results were obtained by using heavier (S+) and lighter (B+) ions under similar conditions

Verificación de la isotropía del hormigón proyectado por vía húmeda

It is well known that there are differences between the fresh mix concrete and the placed concrete sprayed using dry or wet-mix process. Because of that, the characterization of such material is carried out in cores extracted parallel to the spray direction from sample panels. However, in many applications (e.g. tunnel lining), considerable compressive stresses appear along the transversal direction. In this paper different spayed concretes are evaluated. It was observed that the values of compressive strength and modulus of elasticity were different depending on the direction of measurement. These differences are related to a preferential orientation of the coarse aggregate due to the characteristics of the casting process. Rather than applying classic empirical methods, the concrete mixes used in this study were designed according to a new proportioning method based on the difference between the composition of the fresh mix concrete and the placed concrete.Dadas las diferencias entre el hormigón de partida y el colocado, la evaluación de las propiedades de un hormigón proyectado, por vía húmeda o seca, se realiza mediante la extracción de testigos, evaluándose las propiedades mecánicas o deformacionales de forma uniaxial, según la dirección de la proyección. No obstante, son muchas las aplicaciones, como es el caso del sostenimiento en túneles, en las que esta disposición no representa la forma de trabajo principal del hormigón en la estructura. En el presente artículo se ha verificado que pueden existir diferencias en la resistencia a compresión y módulo de elasticidad del hormigón proyectado por vía húmeda, según la dirección de evaluación. Éstas van ligadas a la orientación que sufre el árido grueso como consecuencia de la puesta en obra del hormigón. Asimismo, el hormigón proyectado del estudio se ha dosificado utilizando como procedimiento de dosificación una propuesta metodológica, basada en las diferencias entre hormigón colocado y de partida, en contraposición a los métodos habituales de dosificación que se fundamentan en la experiencia

Antígenos leucocitarios como genes candidatos para mejorar la respuesta inmune en cerdos

Leukocyte antigens (CD) have functions related to immune response and are of interest as classical candidate genes for health. Polymorphisms (e.g. SNPs) in these genes may be associated with variation in the immune response and consequently in disease response. This approach is being taken in search of susceptibility genes for swine disease. In addition, these genes may vary between populations, especially where specific adaptation to pathogens has occurred, and are of potential interest in characterising pig biodiversity.Los antígenos leucocitarios (CD) tienen funciones relacionadas con la respuesta inmune y son de interés con genes candidatos clásicos para la salud. Los Polimorfismos (ej. SNPs) en estos genes pueden estar asociados con variaciones en la respuesta inmune y consecuentemente con la respuesta a la enfermedad. Este ensayo se está desarrollando en la búsqueda de susceptibilidades genéticas a enfermedades porcinas. Adicionalmente, estos genes pueden variar entre poblaciones, especialmente en la que han ocurrido adaptaciones a patógenos, y suponen un interés potencial para la caracterización de la biodiversidad porcina