347 research outputs found
Metamodel-based design optimization of structural one-way slabs based on deep learning neural networks to reduce environmental impact
This article presents a methodology for the construction and use of metamodels with Deep Learning (DL) methods that are useful for making multi-criteria decisions in the design and optimization of one-way slabs. The main motivation behind this research has been to examine the possibilities of improving slab design by including this methodology in future tools, which is capable of calculating thousands of solutions in real time based on the designer's specifications. The process of creating these metamodels begins by developing a database of millions of combinations of slab designs. These combinations are calculated with a heuristic algorithm that provides the following results: rigidity, deflection, cost per square meter, CO2 emissions and embodied energy. Once a database including the entire universe of possible solutions has been created, a metamodel is developed that is capable of condensing the implicit knowledge contained in the database. This metamodel is included within a Decision Support System (DSS) that produces thousands of solutions for slabs that all comply with a range of specifications designated by the design plan. Furthermore, the methodology described herein proposes the use of Pareto-optimal solutions and graphic tools to help designers make multi-criteria decisions regarding the solutions that best fit their needs. A case study is presented to illustrate this proposal: optimizing slab design in two buildings according to technical, economic and sustainability criteria. The results indicate that the multi-criteria solutions obtained would entail a significant reduction in both emissions and embodied energy as compared to mono-criteria solutions, without significantly increasing costs. © 201
Evaluation of crumb rubber as aggregate for automated manufacturing of rubberized long hollow blocks and bricks
Waste tire rubber is a promising lightweight aggregate for building products that enhances their thermal and acoustic properties. Even the environmental benefits of its use are evident, higher cost and significant changes in compressive strength and workability hinder its widespread adoption. This article examines the use of crumb rubber (CR) as aggregate in dry-mix mortars to produce rubberized long hollow blocks and bricks using automated brick machines. CR was incorporated over a range of 10-40% with water/ cement ratio varying from 0.7 to 0.9. The production of rubberized bricks exhibited better performance than long hollow blocks in factory trials. Tests showed important deformations and drastic reduction in compressive strength, especially for crumb rubber percentages greater than 20%. Due to this and the high cost of CR, caution must be taken with the design of new rubberized building products to make sure they are profitable. (C) 2015 Elsevier Ltd. All rights reserved.Peer reviewe
Efectos del diseño y la construcción sobre la huella de carbono en columnas de hormigón armado para edificios residenciales
Constructing structural elements requires high performance materials. Important decisions about geometry and materials are made during the design and execution phases. This study analyzes and evaluates the relevant factors for reinforced concrete columns made in situ for residential buildings. This article identifies and highlights the most sensitive aspects in column design: geometry, type of cement, and concrete strength performance. Using C-40 concrete mixed with CEM-II proved to cut costs (up to 17.83%) and emissions (up to 13.59%). The ideal combination of rebar and concrete is between 1.47 and 1.73: this is the percentage of the ratio between the area of rebar and the area of the concrete section. The means used during the execution phase affect resource optimization. The location of a building has only a minor impact, wherein the wind zone exercises more influence than topographic altitude.La construcción de elementos estructurales requiere materiales de alto rendimiento. Las decisiones sobre la geometría y materiales se toman durante las fases de diseño y ejecución. Este estudio analiza y evalúa factores relevantes para columnas de hormigón armado en edificios residenciales. El trabajo identifica y resalta los aspectos más sensibles en el diseño de columnas: geometría, tipo de cemento y rendimiento de resistencia del concreto. El uso de hormigón C-40 mezclado con CEM-II demostró reducir costes (hasta 17.83%) y emisiones (hasta 13.59%). La combinación ideal de barras de refuerzo y concreto está entre 1.47 y 1.73: este es el porcentaje de la relación entre área de barras de refuerzo y área de la sección de hormigón. Los medios utilizados durante la fase de ejecución afectan la viabilidad de optimizar los recursos. La ubicación del edificio tiene un impacto menor, la zona eólica ejerce más influencia que la altitud topográfica
FDG-PET: a new diagnostic approach in hip prosthesis infection
Infection following hip arthroplasties can present a diagnostic challenge. No
test is 100 % sensitive and 100 % specific; this prospective study was undertaken
to evaluate the utility of FDG-PET imaging for diagnosing infected joint
replacements. 24 hip joint replacements were studied prospectively and we have
complete diagnoses with clinical signs and symptoms, laboratory test,
radiography, joint aspiration, radionuclide imaging including FDG-PET, and
histopathologic examination. 11 of 24 prostheses were infected. The sensitivity
and specificity of PET for detecting infection associated with prostheses were
64,3 % and 64,7 % respectively, in our hands. FDG imaging is not useful in
patients with suspected prosthetic infection like a screening tes
Evaluación combinada de los impactos ambientales, económicos y sociales de soluciones estructurales para la construcción de viviendas
Sustainable development in construction is based on three fundamental pillars: economic, environmental and social. This type of approach aims to identify the best possible solutions for sustainably developing structures by conducting a joint evaluation of the impact on those three pillars. The proposed methodology incorporates metadata on the Spanish construction sector. First, a discrete database is generated with 360 alternatives covering a range of common solutions in residential building. A Pareto algorithm is utilized to select the optimal choices and the wide range of solutions is reduced to the 5 % of the initial group. The project manager is therefore provided with an objective assessment of suitable structural alternatives including the overall joint economic, social, and environmental impact. The results obtained demonstrate the importance and utility of the proposed methodology for sustainable construction.El desarrollo sostenible aplicado a la construcción se basa en tres pilares fundamentales: económico, medioambiental y social. El objetivo principal es identificar las mejores soluciones en términos de desarrollo sostenible de alternativas estructurales a partir de la evaluación conjunta de los impactos en dichos pilares. La metodología propuesta incorpora metadatos con información del sector de la construcción en España. Primero se genera una base de datos discreta de 360 alternativas estructurales que cubren el rango de soluciones habituales en edificación residencial. La selección de alternativas óptimas se realiza mediante el algoritmo de Pareto. El abanico de soluciones se reduce al 5 % de las iniciales. Se aporta una valoración objetiva que orienta al proyectista en la selección de alternativas estructurales idóneas, visualizando de forma conjunta el impacto económico, social y ambiental. Los resultados obtenidos muestran la importancia y utilidad de la metodología propuesta en el campo de la construcción sostenible
Monitoring new long-lasting intravitreal formulation for glaucoma with vitreous images using optical coherence tomography
Intravitreal injection is the gold standard therapeutic option for posterior segment patholo-gies, and long-lasting release is necessary to avoid reinjections. There is no effective intravitreal treatment for glaucoma or other optic neuropathies in daily practice, nor is there a non-invasive method to monitor drug levels in the vitreous. Here we show that a glaucoma treatment combining a hypotensive and neuroprotective intravitreal formulation (IF) of brimonidine–Laponite (BRI/LAP) can be monitored non-invasively using vitreoretinal interface imaging captured with optical coherence tomography (OCT) over 24 weeks of follow-up. Qualitative and quantitative characterisation was achieved by analysing the changes in vitreous (VIT) signal intensity, expressed as a ratio of retinal pigment epithelium (RPE) intensity. Vitreous hyperreflective aggregates mixed in the vitreous and tended to settle on the retinal surface. Relative intensity and aggregate size progressively decreased over 24 weeks in treated rat eyes as the BRI/LAP IF degraded. VIT/RPE relative intensity and total aggregate area correlated with brimonidine levels measured in the eye. The OCT-derived VIT/RPE relative intensity may be a useful and objective marker for non-invasive monitoring of BRI/LAP IF
Tomografía por emisión de positrones en el cáncer de mama
PET18FDG is an imaging diagnostic technique that shows changes in glycolitic metabolism that appear at a very early phases in the tumoral process. The main limitation of PET in breast cancer is the detection of small tumor lesions and axillary micrometastases. However it offers important information in the staging of high risk patients, in clinical relapse or in therapeutic evaluation. The new PET-CT devices offer advantages over conventional techniques. It provides a greater precision in the localization of tumoral foci. In spite of current difficulties for clinical applications, fluoro-estradiol (18F-ES) offers the possibilty of studying the presence of estrogenic receptors both in the primary and in the metastases. It may prove to be a useful tool to obtain information about therapeutic management and prognosis of breast cancer
Surgical treatment for colorectal cancer: Analysis of the influence of an enhanced recovery programme on long-term oncological outcomes-a study protocol for a prospective, multicentre, observational cohort study
Introduction
The evidence currently available from enhanced recovery after surgery (ERAS) programmes concerns their benefits in the immediate postoperative period, but there is still very little evidence as to whether their correct implementation benefits patients in the long term. The working hypothesis here is that, due to the lower response to surgical aggression and lower rates of postoperative complications, ERAS protocols can reduce colorectal cancer-related mortality. The main objective of this study is to analyse the impact of an ERAS programme for colorectal cancer on 5-year survival. As secondary objectives, we propose to analyse the weight of each of the predefined items in the oncological results as well as the quality of life.
Methods and analysis
A multicentre prospective cohort study was conducted in patients older than 18 years of age who are scheduled to undergo surgery for colorectal cancer. The study involved 12 hospitals with an implemented enhanced recovery protocol according to the guidelines published by the Spanish National Health Service. The intervention group includes patients with a minimum implementation level of 70%, and the control group includes those who fail to reach this level. Compliance will be studied using 18 key performance indicators, and the results will be analysed using cancer survival indicators, including overall survival, cancer-specific survival and relapse-free survival. The time to recurrence, perioperative morbidity and mortality, hospital stay and quality of life will also be studied, the latter using the validated EuroQol Five questionnaire. The propensity index method will be used to create comparable treatment and control groups, and a multivariate regression will be used to study each variable. The Kaplan-Meier estimator will be used to estimate survival and the log-rank test to make comparisons. A p value of less than 0.05 (two-tailed) will be considered to be significant.
Ethics and dissemination
Ethical approval for this study was obtained from the Aragon Ethical Committee (C.P.-C.I. PI20/086) on 4 March 2020. The findings of this study will be submitted to peer-reviewed journals (BMJ Open, JAMA Surgery, Annals of Surgery, British Journal of Surgery). Abstracts will be submitted to relevant national and international meetings.
Trial registration number NCT04305314
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