Mechanical and Geometric Performance of PLA-Based Polymer Composites Processed by the Fused Filament Fabrication Additive Manufacturing Technique.

In this work, the effect of short carbon fibre (CF) on the mechanical and geometric properties of 3D printed polylactic acid (PLA) composite parts processed using the Fused Filament Fabrication (FFF) technique have been analysed. Tensile, flexural and interlaminar shear strength (ILSS) tests were performed to obtain the mechanical performance of the different samples. The surface quality and geometric accuracy of the printed specimens were also evaluated. Finally, Scanning Electron Microscope (SEM) images of the printed samples are analysed. The results revealed that the addition of carbon fibres effectively improved all assessed mechanical properties of PLA-CF composites as compared to the neat PLA. In particular, Flat PLA-CF samples showed an average increase in tensile performance of 47.1% for the tensile strength and 179.9% for the tensile stiffness in comparison to the neat PLA. From the flexural behaviour point of view, Flat PLA-CF samples revealed an increase in average flexural strength and stiffness of 89.75% and 230.95%, respectively in comparison to the neat PLA. Furthermore, PLA-CF samples depicted the best ILSS performance. In general, the use of short carbon fibre as reinforcement did not affect the dimensional accuracy of the PLA-CF samples, and even improved the surface roughness in certain cases, particularly in Flat and On-edge orientations.

Evolución posquirúrgica a largo plazo de la hernioplastia inguinal laparoscópica TAPP y TEP en el Hospital Nacional Rosales / Long-term postoperative evolution of the laparoscopic inguinal hernioplasty TAPP and TEP in the Rosales National Hospital

La reparación de la hernia inguinal es el procedimiento más común en cirugía general en todo el mundo. Cada año, aproximadamente 20 millones de hernias se reparan en todo el mundo, de ellas, casi 700,000 se reparan en Europa y EE.UU. La reparación de hernia inguinal es uno de los procedimientos quirúrgicos más comúnmente realizados, y esto trae consigo sobre una importante carga de costes y morbilidad a nivel mundial. La selección de una técnica quirúrgica óptima para la reparación de la hernia inguinal, que permita un rendimiento seguro y una recuperación rápida sin quejas a largo plazo, puede contribuir significativamente a la reducción de los costos nacionales de atención médica. La primera técnica para la reparación de la hernia inguinal fue descrita por E. Bassini en 1887. Desde entonces, se han introducido más de 70 métodos. Hoy en día, solo quedan tres técnicas que han sido científicamente validadas y pueden recomendarse para su aplicación clínica: 1. la técnica Shouldice, una forma de reparación con sutura, 2. reparación abierta con materiales protésicos (mallas) de acuerdo con Lichtenstein, y 3. laparoscópica / reparación de malla plana posterior endoscópica. Las tres técnicas muestran ventajas y desventajas específicas con respecto a la dificultad de rendimiento, materiales, complicaciones y tasas de recurrencia, tiempos de recuperación y tasas de dolor agudo y crónico. Además, en una era de gastos de atención de la salud cada vez mayores, es importante evaluar la carga financiera de estas técnicas atribuible a la operación (costos directos) y el período de recuperación (costos indirectos)

Additive Manufacturing of PLA-Based Composites Using Fused Filament Fabrication: Effect of Graphene Nanoplatelet Reinforcement on Mechanical Properties, Dimensional Accuracy and Texture.

Fused filament fabrication (FFF) is a promising additive manufacturing (AM) technology due to its ability to build thermoplastics parts with advantages in the design and optimization of models with complex geometries, great design flexibility, recyclability and low material waste. This technique has been extensively used for the manufacturing of conceptual prototypes rather than functional components due to the limited mechanical properties of pure thermoplastics parts. In order to improve the mechanical performance of 3D printed parts based on polymeric materials, reinforcements including nanoparticles, short or continuous fibers and other additives have been adopted. The addition of graphene nanoplatelets (GNPs) to plastic and polymers is currently under investigation as a promising method to improve their working conditions due to the good mechanical, electrical and thermal performance exhibited by graphene. Although research shows particularly promising improvement in thermal and electrical conductivities of graphene-based nanocomposites, the aim of this study is to evaluate the effect of graphene nanoplatelet reinforcement on the mechanical properties, dimensional accuracy and surface texture of 3D printed polylactic acid (PLA) structures manufactured by a desktop 3D printer. The effect of build orientation was also analyzed. Scanning Electron Microscope (SEM) images of failure samples were evaluated to determine the effects of process parameters on failure modes. It was observed that PLA-Graphene composite samples showed, in general terms, the best performance in terms of tensile and flexural stress, particularly in the case of upright orientation (about 1.5 and 1.7 times higher than PLA and PLA 3D850 samples, respectively). In addition, PLA-Graphene composite samples showed the highest interlaminar shear strength (about 1.2 times higher than PLA and PLA 3D850 samples). However, the addition of GNPs tended to reduce the impact strength of the PLA-Graphene composite samples (PLA and PLA 3D850 samples exhibited an impact strength about 1.2-1.3 times higher than PLA-Graphene composites). Furthermore, the addition of graphene nanoplatelets did not affect, in general terms, the dimensional accuracy of the PLA-Graphene composite specimens. In addition, PLA-Graphene composite samples showed, in overall terms, the best performance in terms of surface texture, particularly when parts were printed in flat and on-edge orientations. The promising results in the present study prove the feasibility of 3D printed PLA-graphene composites for potential use in different applications such as biomedical engineering.

Optimal Control for Aperiodic Dual-Rate Systems With Time-Varying Delays.

In this work, we consider a dual-rate scenario with slow input and fast output. Our objective is the maximization of the decay rate of the system through the suitable choice of the n-input signals between two measures (periodic sampling) and their times of application. The optimization algorithm is extended for time-varying delays in order to make possible its implementation in networked control systems. We provide experimental results in an air levitation system to verify the validity of the algorithm in a real plant.

Design of a Low-Cost Air Levitation System for Teaching Control Engineering.

Air levitation is the process by which an object is lifted without mechanical support in a stable position, by providing an upward force that counteracts the gravitational force exerted on the object. This work presents a low-cost lab implementation of an air levitation system, based on open solutions. The rapid dynamics makes it especially suitable for a control remote lab. Due to the system's nature, the design can be optimized and, with some precision trade-off, kept affordable both in cost and construction effort. It was designed to be easily adopted to be used as both a remote lab and as a hands-on lab.

Dried blood as an alternative to plasma or serum for Trypanosoma cruzi IgG detection in screening programs.

Trypanosoma cruzi serological screening is recommended for people potentially exposed to this parasite in countries where Trypanosoma cruzi is endemic and those where it is not endemic. Blood samples on filter paper may be a practical alternative to plasma/serum for antibody detection. Using the Architect Chagas assay, we detected the presence of IgG against T. cruzi in matched serum and dried blood spots (DBS) collected from 147 patients residing in Madrid, Spain, who had potential previous exposure to T. cruzi. The κ statistic for the DBS/serum proportion of agreement for the detection of antibodies against T. cruzi was 0.803, considering an S/CO (assay result unit; chemiluminescent signal from the sample [S] divided by the mean chemiluminescent signal for the three calibrators used in the test [CO]) cutoff value of ≥1.00. The relative sensitivity of the Architect test using DBS increased from 95.2% to 98.8% when the cutoff was lowered from ≥1.00 to ≥0.88, while the relative specificity decreased from 84.1% to 71.6%. Overall, the median S/CO values for DBS were significantly lower than those for serum (2.6 versus 6.5; P < 0.001). Discrepancies that occurred with the use of DBS included 10 false positives (with low S/CO values in 9 cases [median, 2.13]) and 4 false negatives, with mean S/CO values of 0.905 (gray zone). Using DBS plus a highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) may be a simple and reliable method for detecting IgG against T. cruzi when blood sampling by venipuncture is not feasible. This method may also reduce the false-negative rates observed with some rapid diagnostic tests. The lower relative sensitivity compared to the reference method may be increased by lowering the optical density threshold.

Virtual and remote robotic laboratory using EJS, MATLAB and LabVIEW.

This paper describes the design and implementation of a virtual and remote laboratory based on Easy Java Simulations (EJS) and LabVIEW. The main application of this laboratory is to improve the study of sensors in Mobile Robotics, dealing with the problems that arise on the real world experiments. This laboratory allows the user to work from their homes, tele-operating a real robot that takes measurements from its sensors in order to obtain a map of its environment. In addition, the application allows interacting with a robot simulation (virtual laboratory) or with a real robot (remote laboratory), with the same simple and intuitive graphical user interface in EJS. Thus, students can develop signal processing and control algorithms for the robot in simulation and then deploy them on the real robot for testing purposes. Practical examples of application of the laboratory on the inter-University Master of Systems Engineering and Automatic Control are presented.

Evaluación de un nuevo dispositivo de conexión para los catéteres de hemodiálisis / Evaluation of a new haemodialysis catheter connector

Los pacientes en hemodiálisis tienen cada vez una edad más avanzada y esto hace que aumente el número de complicaciones en su acceso vascular. Las infecciones de los catéteres tunelizados provocan una alta morbi-mortalidad. El dispositivo conector de sellado microbiológica y mecánicamente TEGO® se utiliza en sustitución del tapón convencional con el que se cierran las luces del catéter presentando la ventaja de que sólo se cambia una vez a la semana. Esto hace que al existir menos manipulación de la vía central aparezcan menos complicaciones e infecciones. Además ofrece una doble barrera de seguridad a la entrada de aire y salida de sangre representadas por la pinza del catéter y el tapón. Para evaluar este dispositivo hemos realizado un estudio en el cual comparamos los tapones TEGO® con los tapones convencionales, analizando los siguientes aspectos: presiones del circuito, eficacia dialítica e infecciones del catéter. El estudio tuvo una duración de dos meses y en él participaron doce pacientes portadores de catéter tunelizado. Nuestros resultados indican que no existen diferencias significativas en cuanto a las presiones del circuito y a la eficacia dialítica entre ambos tipos de tapones. Durante el estudio no hubo ninguna infección pericatéter. Creemos que el dispositivo TEGO® por sus especiales características, puede ser el sistema de cierre ideal para todo tipo de catéteres (AU)

Patients on haemodialysis are becoming increasingly older and this means there is an increase in the number of vascular access complications. Infections of tunnelled catheters cause a high morbidity/mortality. The TEGO® microbiologically and mechanically sealed connector is used instead of the conventional cap used to close the catheter ends, and has the advantage that it is only changed once a week. This means that as there is less handling of the central venous catheter, fewer complications and infections appear. It also offers a double security barrier against the entry of air and exit of blood represented by the catheter clamp and the cap. To evaluate this device, we have carried out a study in which we compared the TEGO® connectors with conventional caps, analysing the following aspects: circuit pressures, dialysis efficacy and catheter infections. The study lasted for two months and included the participation of twelve patients using a tunnelled catheter. Our results show that there are no significant differences with regard to circuit pressures and dialysis efficacy between the two different types of caps. During the study there was no pericatheter infection. We believe that the TEGO® device, on account of its special characteristics, may be the ideal closure system for all kind of catheters (AU)

Estudio comparativo de tres técnicas de hemodiálisis: AFB-K, Hemodiafi ltración y Hemodiálisis de alto flujo / Comparative study of three haemodialysis techniques: AFB-K, Haemodiafi ltration and High-fl ow Haemodialysis

La investigación en nefrología pretende encontrar técnicas cada vez más eficientes de depuración extrarrenal. La técnica dialítica biofiltración sin acetato con perfil de potasio pretende ofrecer una mejor tolerancia y reducir el riego de arritmias. Nuestro objetivo fue comparar está técnica con la hemodiálisis de alto flujo y la hemodiafiltración con el fi n de averiguar que tratamiento dialítico es más adecuado para cada paciente. Estudio controlado, prospectivo y cruzado en el cual los mismos pacientes han sido su propio control. La elección de los pacientes y de la técnica fue aleatoria dializándose los pacientes durante 13sesiones consecutivas con cada una de las técnicas objeto del estudio. Durante todo el estudio se mantuvieron constantes los siguientes parámetros de diálisis: duración de la sesión, flujo, calibre delas agujas y dosis de heparina. A los quince días de comenzar cada período se realizó a los pacientes un electrocardiograma y una analítica (todo pre y post diálisis).En las técnicas biofiltración y hemodiafiltración el valor del bicarbonato es más fisiológico. Con la biofiltración y la hemodiálisis de alto flujo se consigue la investigación en nefrología pretende encontrar técnicas cada vez más eficientes de depuración extrarrenal. La técnica dialítica biofiltración sinacetato con perfil de potasio pretende ofrecer una mejor tolerancia y reducir el riego de arritmias. Nuestro objetivo fue comparar está técnica con la hemodiálisis de alto flujo y la hemodiafiltración con el fi n de averiguar que tratamiento dialítico es más adecuado para cada paciente. Estudio controlado, prospectivo y cruzado en el cual los mismos pacientes han sido su propio control. La elección de los pacientes y de la técnica fue aleatoria dializándose los pacientes durante 13sesiones consecutivas con cada una de las técnicas objeto del estudio. Durante todo el estudio se mantuvieron constantes los siguientes (..) (AU)

Research in nephrology seeks to find increasing y efficient extrarenal purification techniques. The dialysis technique of potassium-profi led acetate free biofiltration offers better tolerance and reduces the risk of arrhythmias. Our aim was to compare this technique with high-flow haemodialysis and with haemodia filtration in order to ascertain which dialysis treatment is the most suitable for each patient. A prospective, controlled cross study in which the same patients were their own control group. The choice of patients and technique was random, with the patients undergoing 13 consecutive sessions of dialysis with each of the techniques being studied. Throughout the study, the following dialysis parameters were kept constant: duration of the session, flow, calibre of the needs and dose of heparin. Fifteen days after starting each period, patients were given an electrocardiogram and blood test (all pre and post dialysis).With the biofiltration and haemodia filtration technique the bicarbonate value is more physiological. With biofiltration and high-flow haemodialysis a better correction of the acid-base balance is achieved. As regards sodium value, there are small differences in the three techniques, always with in the physiological interval. In haemodia-filtration, episodes of arrhythmia increased. The three methods have shown correct dialysis efficiency, tolerance and cardiovascular stability (AU)

Hemodiálisis domiciliaria diaria en dos pacientes / No disponible

No disponible

Evaluation of COBAS Ampliprep automated nucleic acid extraction for genotyping human papillomavirus (HPV) by the Roche linear array HPV test

No disponible

[Detection and genotyping of high-risk human papillomavirus in cervical specimens]. / Detección y genotipado del virus del papiloma humano de alto riesgo en muestras de lesiones cervicales.

INTRODUCTION: This study investigates the relationship between various human papillomavirus (HPV) genotypes and the results of cytological and histological analysis of cervical samples using two complementary assays for HPV detection (hybrid capture and PCR). We studied the impact of HPV genotype on the presence of pre-cancerous cervical lesions and cervical cancer, as well as the association between HPV viral load and the presence of high-risk HPV as determined by PCR. METHODS: A total of 272 women were studied. Most of them presented cellular alterations consistent with cervical lesions due to HPV and all had high-risk HPV as detected by hybrid capture testing. Histological studies were undertaken, and HPV genotyping by PCR based on microarrays was performed. RESULTS: HPV-DNA was not detected or genotypes could not be identified by PCR in 22.06% of the patients. Genotype 16 and/or 18 was detected in 33% of 212 patients. Mixed infections with several genotypes were found in 25% of patients. The histological lesions associated with the various genotypes were as follows: genotype 16 and/or 18. were detected in 55.73% of the 61 patients with H-SIL and cancer, whereas these genotypes were detected in only 7.9% and 22% of women with ASCUS and L-SIL (P < 0.05). Viral load was less than 3 pg/mL in 12.13% of the women studied. In this group of patients, high-risk HPV was present in 39.39%. In the group of patients who had a viral load greater than 3 pg/mL, high risk-HPV was detected in 77.4% (P < 0.05). CONCLUSIONS: Genotypes 16 and/or 18 were detected in most patients with a diagnosis of H-SIL. Other high-risk-HPV genotypes were much less prevalent. Hybrid capture testing is a useful screening test. PCR was effective for identifying genotypes 16 and 18. Histological and cytological findings in cervical samples should be interpreted together with high-risk HPV detection.

Detección y genotipado del virus del papiloma humano de alto riesgo en muestras de lesiones cervicales / Detection and genotyping of high-risk human papillomavirus in cervical specimens

Introducción. El objetivo del presente estudio es utilizando dos técnicas complementarias de detección del virus del papiloma humano (VPH) (captura de híbridos [CH] y reacción en cadena de la polimerasa [PCR]), relacionar el estudio citológico y/o la biopsia de cérvix con la presencia de distintos genotipos del VPH, para conocer la influencia de éstos en la producción de lesiones precancerosas y cáncer cervical, así como relacionar la carga viral con la presencia de VPH-AR (alto riesgo) determinados por PCR. Métodos. Se han estudiado 272 mujeres que presentaban la mayoría alteraciones celulares compatibles con lesiones cervicales por el VPH. En todas se ha detectado VPH de alto riesgo por el método de CH y se realizó estudio histológico y detección del genotipo del VPH por técnica de PCR. Resultados. En el 22,06% de las pacientes no se detectó ADN de VPH con la técnica de PCR. El genotipo 16 y/o 18 fue el prevalente y se encontró en el 33% de las 212 mujeres estudiadas. Se hallaron infecciones mixtas por varios genotipos en el 25% de estas 212 pacientes. En cuanto a las lesiones histológicas encontradas, en 61 pacientes con lesiones escamosas intraepiteliales de alto grado (H-SIL) y cáncer, el 55,73% presentaban genotipos 16 y/o 18, mientras que en 38 pacientes con presencia de células escamosas alteradas de significado incierto (ASCUS) y en 126 con lesiones escamosas intraepiteliales de bajo grado (L-SIL), se pusieron de manifiesto estos genotipos únicamente en el 7,9 y 22,2%, respectivamente, estableciéndose una relación estadísticamente significativa (p 3 pg/ml, se encontró VPH-AR en el 77,40% de éstas, siendo esta relación significativa (p < 0,05). Conclusiones. En las pacientes con biopsia de H-SIL hemos encontrado mayoritariamente la presencia de los genotipos 16 y/o 18. La técnica de CH es útil como procedimiento de cribado. La técnica de PCR es interesante para identificar los genotipos 16 y 18. Es conveniente que los resultados de los tests de detección del VPH se interpreten conjuntamente con los de biopsia y citología (AU)

INTRODUCTION. This study investigates the relationship between various human papillomavirus (HPV) genotypes and the results of cytological and histological analysis of cervical samples using two complementary assays for HPV detection (hybrid capture and PCR). We studied the impact of HPV genotype on the presence of pre-cancerous cervical lesions and cervical cancer, as well as the association between HPV viral load and the presence of high-risk HPV as determined by PCR. METHODS. A total of 272 women were studied. Most of them presented cellular alterations consistent with cervical lesions due to HPV and all had high-risk HPV as detected by hybrid capture testing. Histological studies were undertaken, and HPV genotyping by PCR based on microarrays was performed. RESULTS. HPV-DNA was not detected or genotypes could not be identified by PCR in 22.06% of the patients. Genotype 16 and/or 18 was detected in 33% of 212 patients. Mixed infections with several genotypes were found in 25% of patients. The histological lesions associated with the various genotypes were as follows (..) (AU)

Urgencias en diálisis en toda una provincia. Resultados preliminares / No disponible

No disponible

[Seroepidemiologic study of hepatitis A in the community of Madrid during the year 2002]. / Estudio seroepidemiológico de la hepatitis A en la comunidad de Madrid durante el año 2002.

INTRODUCTION: The aim of this study was to investigate the prevalence and risk factors associated with hepatitis A virus (HAV) infection in a representative population sample to determine who can benefit from vaccination strategies and to investigate the age limit at which previous HAV antibody screening is not required. METHODS: From April to September 2002, we studied a total of 557 patients, 90 children and 467 blood donors, aged 1-65 years. Information on demographic variables (age, gender, place of residence and education level) was recorded. Patients with history of hepatitis or other liver diseases were excluded. Anti-HAV antibodies (IgG) were determined with an automated enzyme immunoassay (AxSYM, Abbott Diagnostics). The chi-square and Mantel-Haenszel tests were used for the statistical analysis. RESULTS: The overall prevalence of HAV infection was 41.5%. There was a significant increase in prevalence with age (chi-square TL:205, P < .0001), with rates from the youngest to oldest groups of 5.5%, 23.5%, 28.1%, 64.2% and 93.2%, respectively. Apart from age, the only other risk factor independently associated with prevalence was the level of education, with higher prevalence at the lower education levels (OR 5 2.7; chi-square = 32.11, P < .0001). CONCLUSIONS: The prevalence of anti-HAV antibodies has decreased in recent years in the community of Madrid. Among the population less than 35 years of age, 75% of individuals are susceptible to the infection and could benefit from universal vaccination without previous screening for anti-HAV antibodies.

Utilidad del sistema de Biofeedback Diacontrol, en la monitorización de las sesiones de hemodiálisis / The usefulness of the biofeedback system diacontrol in monitoring sessions of haemodialysis

No disponible