Rotura de cotilo en artroplastia total de cadera

Describimos dos casos de rotura de cotilos de expansión de prótesis de cadera tipo CLS de origen no traumático. Ambos casos sucedieron a los seis años de cirugía y no se apreció desgaste o rotura del polietileno en ninguno de ellos. En nuestra opinión la hipótesis más probable es que la falta de contacto entre la zona polar del cotilo y el fondo del acetábulo produzca una zona de inestabilidad en los segmentos de la prótesis y rotura por fatiga del material. Creemos que es obligado su recambio aunque el paciente no presente sintomatología actual, ya que la rotura del acetábulo conducirá a un aflojamiento y a una osteolisis secundaria.We describe two cases of breakage of expansion cups in a CLS uncemented total hip arthroplasty wihtout traumatic etiologic. Both cases occurred six years after the surgery and none had breakage or polyethylene wear. We postulate that the lack of contact between the polar area of the cup and the acetabulum produces a zone of instability in the segments of the prosthesis and increases the risk of fatigue of the material. In our opinion acetabular revision is mandatory in this situation, even in asymptomatic cases, because cup rupture leads to implant loosening with secondary short-team osteolysis

Present-Day Crustal Stress Field from Gcmt Focal Mechanisms Based on the Slip Model.

The Slip Model is applied to the Global Centroid Moment Tensor database to determine the present day state of stress. Thus, from each focal mechanism the horizontal shortening direction (Dey) and the shape factor of the strain ellipsoid (k`), defined as the relationship between the maximum horizontal shortening and the vertical axis, are calculated. Additionally, this method proposed the neoformed plane from the calculated nodal planes. In this study, to determine the stress configuration at crustal scale, only depths < 40 km are included. Focal mechanisms are grouped in reverse, strike-slip and normal, to analyse its distribution and to determine the b-parameter from Gutenberg-Richter law. Finally, global shape factor and horizontal shortening direction maps are presented

Determination of reflectance and transmittance of multi-layer of InGaAs and theoretical methods for obtaining of optical constants

5 páginas, 3 figuras, 2 tablas.-- Trabajo presentado al 1st International Congress on Instrumentation and Applied Sciences celebrado en Cancún (México) del 26 al 29 de Octubre de 2010.The theoretical concepts are necessary to obtain the optical constants of several materials in InGaAs Photodiode and are possible to obtain from experimental dates of reflectance and transmittance and several optical coverings can be designed. In this work we will show how to calculate the reflectance of photodiode for all the wavelengths (each 50 nm, according to the data of refractive index), as well as changing to the angle of incidence and polarization s and p, besides the calculation of the transmittance of a multi-layer ones of InGaAs. A multi-layer is constituted by a series of piled up laminae some on others and in this work we will suppose that they are homogenous, isotropic and plane-parallel, the structure is in the first case we have a transparent layer of NSi, late second layer of InP (Zn), soon a third layer of InGaAs and finally a later of InP (S). These multilayers are destined for optical applications, in our case will be case of study in the case of the photodiodes, the thicknesses of the layers will be of the order of the wavelength of incident radiation, which in the case of radiation IR/NIR is translated in thicknesses of approximately between 1y 100 nm. For the determination of optical constants they are possible to be done of different ways in our case we will concentrate in 1) Measured of reflectance in normal incidence. These measures only provide the value of n in the case of means transparents.2) Measured of reflectance in two angles of incidence. It allows to the use of natural light or polarized.3) Two measures of R p R s in two angles of incidence outside the normal one. 4) Rs and Rp in a single angle of incidence outside the normal one.Peer reviewe

Alpine kink bands on foliated rocks of the Central System variscan basement

La asociación espacial y cinemática entre kink bands en rocas con foliación varisca y cabalgamientos alpinos en el basamento del Sistema Central, permiten deducir que los primeros tienen una edad cenozoica, y no varisca o tardivarisca. Sistemáticamente, la dirección de los ejes de los kinks es subparalela a los cabalgamientos. Se estudian tres afloramientos clave: El Cabalgamiento de Villares de Jadraque, el Cabalgamiento de Valdesotos y el Retrocabalgamiento de El Atazar.The spatial and kinematic association between kink bands in rocks with variscan foliation and alpine thrusts in the Central System basement, allow us to deduce that the former have a Cenozoic age, and not variscan or late-variscan. Systematically, the fold axes trend of the kinks is sub-parallel to the strike of the thrusts. Three key outcrops are studied: the Villares de Jadraque thrust, the Valdesotos thrust and the El Atazar back-thrust.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

PEPTIDOS TOXICOS Y NO TOXICOS DE CIANOBACTERIAS EN CUERPOS DE AGUA DULCE DE LA V REGION, CHILE

En Chile se ha detectado la presencia de algunos géneros de cianobacterias que pueden producir potentes hepatotoxinas y neurotoxinas, las que pueden ser letales para humanos y animales. En el presente trabajo se determinó la presencia de dos géneros de cianobacterias no tóxicos: Chroococcus y Spirulina; y cuatro génerosde cianobacterias productores de toxina, Anabaena, Anabaenopsis, Microcystis y Oscillatoria en tres diferentes cuerpos de agua de la V Región: Lago Peñuelas (Valparaíso), Tranque Recreo (Villa Alemana) y Embalse Los Aromos (Limache). Además se detectó la presenciade hepatotoxinas por MALDI-TOF MS encontrándose microcistina-RR, -LA, -YR y nodularina en Embalse Los Aromos, microcistina-LA en Tranque Recreo y microcistina- RR y LA en Lago Peñuelas. Adicionalmente enalgunas de las muestras se detectó la presencia de péptidos no tóxicos, que presentan actividad biológica tales como aeruginosinas, cianopeptolinas y microgininas. Como estos cuerpos de agua dulce sonutilizados para abastecimiento público y para la recreación, es importante diseñar planes de tratamiento y monitoreo para detectar y evitar los riesgos a la salud  humana y animal provocado por estos microorganismos