Characterization of Ti-C-N coatings deposited on Ti6Al4V for biomedical applications.

Ti6Al4V alloy is the most commonly employed implant material for orthopedic replacements due to its good mechanical properties close to those of bones, biocompatibility and its good corrosion resistance in biological media. Nevertheless, it does not exhibit good wear resistance, showing friction and wear even with soft tissues. This latter feature can lead to a premature failure of the implant with the subsequent component replacement. Therefore, a system with good tribological resistance is required for several medical applications. One possible alternative to solve tribological problems consists of protecting the alloy surface by means of biocompatible Ti-C-N coatings. In this work, five types of metallic Ti-C-N coatings deposited by physical vapor deposition (PVD) cathodic arc method on Ti6Al4V substrate have been studied. Different deposition conditions have been analyzed, and the superficial properties of films have been characterized. Additionally, tribological response of these films have been determined and compared with the substrate one under fretting conditions in simulated body fluid. The results indicate that Ti-C-N coatings improve the general response of the biomaterial.

Effect of the growth conditions on the optical and mechanical properties of TiO2 and Al2O3 films.

The mechanical and optical properties of TiO2 and Al2O3 films deposited by DC reactive magnetron sputtering were analysed as a function of the deposition conditions. Two different sputtering powers and three different voltages targets which influence the pressure and the deposition rate were studied. The voltage corresponds to two different percentages of the turn down set point of the hysteresis curve and fully poisoned condition. As their optical application is the main functionality of these coatings, the transparency and the refractive index were investigated. However, the mechanical properties are the key factors for determining the performance of these systems in use. For this, the wear resistance of these coatings was studied through the analysis of the evolution of the friction coefficient with time and the analysis of the wear track. The corrosion resistance has been also analysed through electrochemical studies. The results reveal that there is a clear influence of the studied deposition conditions on the mechanical and optical properties of these films. However, while general conclusions could be drawn for Al2O3 films, for TiO2 films the tendency is not so clear and further work needs to be performed.

Characterisation of tribocorrosion behaviour of multilayer PVD coatings.

The effect of repassivation on tribocorrosion behaviour of two multilayer coatings of different structures is studied experimentally by measuring the variation of instantaneous open-circuit potential during friction. One coating consists of alternating Cr and CrN layers, while another consists of alternated layers of CrN and ZrN. Analysis of the results showed that friction force, i.e. the rate of the mechanical energy supplied to the material in the contact zone, has no direct influence on the tribocorrosion behaviour; however, the wear rate does strongly influence the tribocorrosion. A simple phenomenological model of repassivation of the multilayer coating is developed assuming "surface coverage" approach. This model establishes the relationship between the rate of mechanical activation of material by friction and the behaviour of the open-circuit potential.

[Value of autopsy in a neonatal intensive care unit]. / Valor de la autopsia en una unidad de cuidados intensivos neonatológicos.

OBJECTIVES: 1) To identify the profile of the cases requested for autopsy; 2) to analyze the clinocopathological discordance; 3) to investigate predictive factors for unsuspected clinically relevant diagnoses. PATIENTS AND METHOD: All autopsies performed between January 1999 and December 2005 in a tertiary neonatal intensive care unit, were retrospectively reviewed. Clinicopathological concordance was assessed independently by two neonatologists and two pathologists, according to a modification of the Goldman classification. A comparison was made between newborns who had an autopsy performed and those who did not and predictive factors for unsuspected findings were investigated. RESULTS: During the study period, there were 309 deaths, and autopsies were performed in 128 (41.4 %) of these cases. Autopsies were more common in newborns who had gestational age > 36 weeks (p < 0.001), birthweight > 1500 g (p < 0.001) and congenital defects (p < 0.007). However, the probability that the autopsy was granted decreased with increasing death age (p < 0.016). Unsuspected diagnoses were observed in 49.2 % of the autopsies, being a major finding in 21.1 % of the cases. A clinicopathological discordance involving the prognosis was found in four cases (3.1 %). Relevant unsuspected findings could not be predicted from the ante-mortem clinical diagnosis, gestational age, birthweight, sex, and death age. CONCLUSION: The autopsy remains the "gold standard" method to reveal major and unsuspected diagnoses and there is no substitute for it. Postmortem examination should be requested systematically in every neonatal death. However, several factors such as gestational age, birthweight, presence of congenital defects and death age, influence the likelihood of autopsy being granted.

Valor de la autopsia en una unidad de cuidados intensivos neonatológicos / Value of autopsy in a neonatal intensive care unit

Objetivos: Conocer el perfil de los casos sometidos a autopsia, analizar la discrepancia clinicopatológica e investigar los factores predictivos de un rendimiento alto. Pacientes y método: Se estudiaron retrospectivamente todas las autopsias practicadas en una unidad de cuidados intensivos neonatológicos de tercer nivel entre enero de 1999 y diciembre de 2005. De manera independiente, dos patólogos y dos neonatólogos establecieron la concordancia clinicopatológica según la clasificación de Goldman modificada. Se compararon los neonatos sometidos a autopsia con los que no lo fueron, y se investigaron los factores predictivos de hallazgos insospechados. Resultados: Se practicaron 128 autopsias (41,4 %) en 309 fallecimientos ocurridos durante el período de estudio. Las necropsias se realizaron con más frecuencia en los recién nacidos mayores de 36 semanas de edad gestacional (p < 0,001), peso superior a 1.500 g (p < 0,001) y con malformación (p < 0,007). Sin embargo, la probabilidad de que se concediera la autopsia decreció cuanto mayor era la edad del paciente fallecido (p < 0,016). Se observaron diagnósticos insospechados en el 49,2 % de las necropsias, siendo relevantes en el 21,1 %. En 4 casos (3,1 %) existió una discrepancia clinicopatológica con implicaciones en el pronóstico. No fue posible predecir los hallazgos insospechados relevantes en función del diagnóstico clínico ante mortem, la edad gestacional, el peso al nacer, el sexo y la edad en el momento del fallecimiento. Conclusión: La autopsia continúa siendo el método de referencia e insustituible para demostrar diagnósticos insospechados y relevantes. La necropsia debe solicitarse de manera sistemática ante toda muerte neonatal. Sin embargo, factores como la edad gestacional, el peso de nacimiento, la presencia de malformaciones y la edad de fallecimiento influyen en la probabilidad de ser concedida

Objectives: 1) To identify the profile of the cases requested for autopsy; 2) to analyze the clinocopathological discordance; 3) to investigate predictive factors for unsuspected clinically relevant diagnoses. Patients and method: All autopsies performed between January 1999 and December 2005 in a tertiary neonatal intensive care unit, were retrospectively reviewed. Clinicopathological concordance was assessed independently by two neonatologists and two pathologists, according to a modification of the Goldman classification. A comparison was made between newborns who had an autopsy performed and those who did not and predictive factors for unsuspected findings were investigated. Results: During the study period, there were 309 deaths, and autopsies were performed in 128 (41.4 %) of these cases. Autopsies were more common in newborns who had gestational age > 36 weeks (p < 0.001), birthweight > 1500 g (p < 0.001) and congenital defects (p < 0.007). However, the probability that the autopsy was granted decreased with increasing death age (p < 0.016). Unsuspected diagnoses were observed in 49.2 % of the autopsies, being a major finding in 21.1 % of the cases. A clinicopathological discordance involving the prognosis was found in four cases (3.1 %). Relevant unsuspected findings could not be predicted from the ante-mortem clinical diagnosis, gestational age, birthweight, sex, and death age. Conclusion: The autopsy remains the "gold standard" method to reveal major and unsuspected diagnoses and there is no substitute for it. Postmortem examination should be requested systematically in every neonatal death. However, several factors such as gestational age, birthweight, presence of congenital defects and death age, influence the likelihood of autopsy being granted

Enfermedad de Kawasaki neonatal grave / Severe neonatal Kawasaki disease

No disponible

Determinación de parámetros cinéticos en las pruebas de equilibrio y marcha de pacientes con latigazo cervical / Measurement of kinetic parameters in the balance and gait of patients with whiplash

Introducción. La sintomatología referida como sensación de inestabilidad es muy habitual en pacientes que han sufrido un latigazo cervical. Se trata de un grupo de pacientes en el que habitualmente las pruebas de diagnóstico complementario no ofrecen hallazgos de interés. Pretendemos encontrar hallazgos comunes a la población con latigazo cervical que nos permitan diferenciarla de la sana. Material y métodos. Estudiamos una muestra de 30 pacientes que sufrieron un latigazo cervical en 2004 (7 hombres y 23 mujeres, con edades entre 20 y 72 años). Todos cumplimentaron dos escalas de valoración (Tinetti y Berg) y un estudio de posturografía con plataforma dinamométrica. Comparamos los datos obtenidos en la posturografía con población sana. Resultados. Se han encontrado diferencias significativas en la mayor parte de las pruebas analizadas, sobre todo en la valoración global (23,735). Las pruebas de Romberg con gomaespuma fueron las más sensibles para diferenciar ambas poblaciones (6,966 y 14,258). En las escalas de valoración utilizadas los datos fueron idénticos a la población sana. Los índices sensoriales también se vieron alterados, sobre todo el somatosensorial (21,075) y el vestibular (17,905). Los pacientes con latigazo cervical utilizaron de forma predominante la estrategia de cadera o medio-lateral (56,994) para compensar su inestabilidad. Conclusión. El análisis de los parámetros cinéticos de las pruebas de equilibrio y marcha, a diferencia de las escalas de valoración, permite diferenciar la población con latigazo cervical de la sana. Las pruebas más sensibles son las de Romberg con gomaespuma (ojos abiertos y cerrados)

Introduction. The symptomatology explained as sensation of instability is very usual in patients who have suffered a whiplash injury. In this type of patients the complementary tests of diagnosis do not usually offer findings of interest. With this work we aim to look for common findings to the population suffering whiplash injury so as to differentiate them from the healthy population. Methodology. A sample of 30 patients who suffered a whiplash injury in 2004 (7 men and 23 women, with ages between 20 and 72 years) was studied. All of them filled out the evaluation scales of Tinetti and Berg and performed a study based on gait and balance analysis with a dynamometric platform. Their results were compared to the data of healthy population. Results. Significant differences in most of the tests have been found, especially in the global evaluation (23.735). Romberg tests with foam were the most sensitive to differentiate both populations (6.966 and 14.258). The results obtained from the evaluation scales showed no differences between both groups. The sensorial indexes were also altered, above all, somatosensorial (21.075) and vestibular (17.905). Patients with whiplash injury predominantly used the hip or middle-lateral strategy (56.994) to compensate their instability. Conclusion. The analysis of the kinetic parameters obtained from the tests of balance and gait, unlike the evaluation scales, makes it possible to differentiate the population with whiplash injury from the healthy one. The most suitable tests are those of Romberg with foam (open and closed eyes)

[Undergraduate medical education in Cantabria and its relevance to the new health system]. / Estudio de la formación médica pregraduada en Cantabria y su pertinencia en el nuevo modelo sanitario.

Considering that medical schools should serve the community to which they provide professionals and that, therefore, they should have a knowledge of the community health needs, we evaluated the adequacy of the teaching program of the Medical School of Cantabria and the attitudes and expectations of the medical students. The results showed a majority of students younger than age 20 (90.2%), with a female predominance (68.5%), from upper and middle classes and with professional expectations of becoming a hospital specialist (86.9%) and working in urban media (95.4%). In the analysis of the teaching program a predominance of clinical over social topics was discovered, there was a lack of contact with primary care, the teaching was given as professorial lectures and the education of students was oriented towards hospital specialties. It was concluded that a change in the educational systems is needed for adequacy with the new health care system.