965 resultados para Force-based finite elements


Relevância:

30.00% 30.00%

Publicador:

Resumo:

The European Surveillance of Congenital Anomalies (EUROCAT) network of population-based congenital anomaly registries is an important source of epidemiologic information on congenital anomalies in Europe covering live births, fetal deaths from 20 weeks gestation, and terminations of pregnancy for fetal anomaly. EUROCAT's policy is to strive for high-quality data, while ensuring consistency and transparency across all member registries. A set of 30 data quality indicators (DQIs) was developed to assess five key elements of data quality: completeness of case ascertainment, accuracy of diagnosis, completeness of information on EUROCAT variables, timeliness of data transmission, and availability of population denominator information. This article describes each of the individual DQIs and presents the output for each registry as well as the EUROCAT (unweighted) average, for 29 full member registries for 2004-2008. This information is also available on the EUROCAT website for previous years. The EUROCAT DQIs allow registries to evaluate their performance in relation to other registries and allows appropriate interpretations to be made of the data collected. The DQIs provide direction for improving data collection and ascertainment, and they allow annual assessment for monitoring continuous improvement. The DQI are constantly reviewed and refined to best document registry procedures and processes regarding data collection, to ensure appropriateness of DQI, and to ensure transparency so that the data collected can make a substantial and useful contribution to epidemiologic research on congenital anomalies.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Hem realitzat l’estudi de moviments humans i hem buscat la forma de poder crear aquests moviments en temps real sobre entorns digitals de forma que la feina que han de dur a terme els artistes i animadors sigui reduïda. Hem fet un estudi de les diferents tècniques d’animació de personatges que podem trobar actualment en l’industria de l’entreteniment així com les principals línies de recerca, estudiant detingudament la tècnica més utilitzada, la captura de moviments. La captura de moviments permet enregistrar els moviments d’una persona mitjançant sensors òptics, sensors magnètics i vídeo càmeres. Aquesta informació és emmagatzemada en arxius que després podran ser reproduïts per un personatge en temps real en una aplicació digital. Tot moviment enregistrat ha d’estar associat a un personatge, aquest és el procés de rigging, un dels punts que hem treballat ha estat la creació d’un sistema d’associació de l’esquelet amb la malla del personatge de forma semi-automàtica, reduint la feina de l’animador per a realitzar aquest procés. En les aplicacions en temps real com la realitat virtual, cada cop més s’està simulant l’entorn en el que viuen els personatges mitjançant les lleis de Newton, de forma que tot canvi en el moviment d’un cos ve donat per l’aplicació d’una força sobre aquest. La captura de moviments no escala bé amb aquests entorns degut a que no és capaç de crear noves animacions realistes a partir de l’enregistrada que depenguin de l’interacció amb l’entorn. L’objectiu final del nostre treball ha estat realitzar la creació d’animacions a partir de forces tal i com ho fem en la realitat en temps real. Per a això hem introduït un model muscular i un sistema de balanç sobre el personatge de forma que aquest pugui respondre a les interaccions amb l’entorn simulat mitjançant les lleis de Newton de manera realista.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Ireland has positioned itself to take advantage of technological change by encouraging the inward investment of high-tech industries and by providing a highly-educated workforce to sustain and enlarge them. Employment of science, engineering and technology graduates at all levels has been a hallmark of the modern Irish economy, as the educational sector responded to the mix of skills demanded by industry. An outstanding record of graduate output has contributed to the phenomenal growth in Irish-based technology. In an era of rapid technological change, the goal of "scientific literacy for all" has become a primary objective of a general education. Science is one of three literacy domains, along with reading and mathematics, that is included in measures of educational achievement by the OECD.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A polymerase chain reaction (PCR)-based assay which amplifies repetitive DNA elements present within bacterial genomes was used to characterize and differentiate Leptospira sp. Thirty-five strains from a reference culture collection and 18 clinical isolates which had been previously analyzed by cross agglutinin absorption test (CAAT) were evaluated by this technique. PCR results from analysis of the reference culture collection showed no bands corresponding to serogroups Australis, Autumnalis, Bataviae, Celledoni, Cynopteri, Djasiman, Panama, Pomona, Pyrogenes, and Tarassovi. However, the PCR method was able to clearly discriminate the serogroups Andamana, Ballum, Canicola, Grippotyphosa, Hebdomadis, Icterohaemorrhagiae, Javanica, Sejroe, Semaranga, and Shermani. Clinical isolates previously characterized by CAAT as serovar Copenhageni, serovar Castellonis, and as serovar Canicola were in agreement with PCR results. The clinical isolate previously characterized as serovar Pomona was not differentiated by PCR. Forty additional clinical isolates from patients with leptospirosis obtained in São Paulo, Brazil were also evaluated by this PCR method. Thirty-nine of these were determined to belong to serogroup Icterohaemorrhagiae (97.5%) and one to serogroup Sejroe (2.5%). These results demonstrate that the PCR method described in this study has utility for rapid typing of Leptospira sp. at the serogroup level and can be used in epidemiological survey.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The ENCyclopedia Of DNA Elements (ENCODE) Project aims to identify all functional elements in the human genome sequence. The pilot phase of the Project is focused on a specified 30 megabases (approximately 1%) of the human genome sequence and is organized as an international consortium of computational and laboratory-based scientists working to develop and apply high-throughput approaches for detecting all sequence elements that confer biological function. The results of this pilot phase will guide future efforts to analyze the entire human genome.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Total ankle replacement remains a less satisfactory solution compared to other joint replacements. The goal of this study was to develop and validate a finite element model of total ankle replacement, for future testing of hypotheses related to clinical issues. To validate the finite element model, an experimental setup was specifically developed and applied on 8 cadaveric tibias. A non-cemented press fit tibial component of a mobile bearing prosthesis was inserted into the tibias. Two extreme anterior and posterior positions of the mobile bearing insert were considered, as well as a centered one. An axial force of 2kN was applied for each insert position. Strains were measured on the bone surface using digital image correlation. Tibias were CT scanned before implantation, after implantation, and after mechanical tests and removal of the prosthesis. The finite element model replicated the experimental setup. The first CT was used to build the geometry and evaluate the mechanical properties of the tibias. The second CT was used to set the implant position. The third CT was used to assess the bone-implant interface conditions. The coefficient of determination (R-squared) between the measured and predicted strains was 0.91. Predicted bone strains were maximal around the implant keel, especially at the anterior and posterior ends. The finite element model presented here is validated for future tests using more physiological loading conditions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This thesis suggests to carry on the philosophical work begun in Casati's and Varzi's seminal book Parts and Places, by extending their general reflections on the basic formal structure of spatial representation beyond mereotopology and absolute location to the question of perspectives and perspective-dependent spatial relations. We show how, on the basis of a conceptual analysis of such notions as perspective and direction, a mereotopological theory with convexity can express perspectival spatial relations in a strictly qualitative framework. We start by introducing a particular mereotopological theory, AKGEMT, and argue that it constitutes an adequate core for a theory of spatial relations. Two features of AKGEMT are of particular importance: AKGEMT is an extensional mereotopology, implying that sameness of proper parts is a sufficient and necessary condition for identity, and it allows for (lower- dimensional) boundary elements in its domain of quantification. We then discuss an extension of AKGEMT, AKGEMTS, which results from the addition of a binary segment operator whose interpretation is that of a straight line segment between mereotopological points. Based on existing axiom systems in standard point-set topology, we propose an axiomatic characterisation of the segment operator and show that it is strong enough to sustain complex properties of a convexity predicate and a convex hull operator. We compare our segment-based characterisation of the convex hull to Cohn et al.'s axioms for the convex hull operator, arguing that our notion of convexity is significantly stronger. The discussion of AKGEMTS defines the background theory of spatial representation on which the developments in the second part of this thesis are built. The second part deals with perspectival spatial relations in two-dimensional space, i.e., such relations as those expressed by 'in front of, 'behind', 'to the left/right of, etc., and develops a qualitative formalism for perspectival relations within the framework of AKGEMTS. Two main claims are defended in part 2: That perspectival relations in two-dimensional space are four- place relations of the kind R(x, y, z, w), to be read as x is i?-related to y as z looks at w; and that these four-place structures can be satisfactorily expressed within the qualitative theory AKGEMTS. To defend these two claims, we start by arguing for a unified account of perspectival relations, thus rejecting the traditional distinction between 'relative' and 'intrinsic' perspectival relations. We present a formal theory of perspectival relations in the framework of AKGEMTS, deploying the idea that perspectival relations in two-dimensional space are four-place relations, having a locational and a perspectival part and show how this four-place structure leads to a unified framework of perspectival relations. Finally, we present a philosophical motivation to the idea that perspectival relations are four-place, cashing out the thesis that perspectives are vectorial properties and argue that vectorial properties are relations between spatial entities. Using Fine's notion of "qua objects" for an analysis of points of view, we show at last how our four-place approach to perspectival relations compares to more traditional understandings.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Empirical studies have recently pointed towards a socio-structural category largely overlooked in social inequality research: the dynamic positions of households adjacent to those of the poor and yet not representing those of the established, more prosperous positions in society. These results suggest that the population in this category fluctuates into and out of poverty more often than moving into and out of secure prosperity. This category - still lacking theoretical conceptualization - is characterized by both precariousness and a certain degree of prosperity; despite a restricted and uncertain living standard it holds a range of opportunities for action. We seek analytical elements to conceptualize 'precarious prosperity' for comparative empirical research by subjecting various concepts of social inequality research to critical scrutiny. We then operationally define 'precarious prosperity' to screen for this population in three countries. Based on qualitative interviews with households in precarious prosperity, we present first analyses of perceptions and household strategies that underline the relevance of the concept in different countries.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Aquest projecte consisteix en aplicar el càlcul no lineal en la modelització volumètricanumèrica de l’estructura del sistema de descàrrega d’una columna del claustre de lacatedral de Girona mitjançant el mètode dels elements finits. A la Universitat de Gironas’ha fet diferents estudis del claustre de la catedral de Girona però sempre simulant uncomportament lineal de les característiques dels materials. El programa utilitzat és la versió docent del programa ANSYS disponible al Dept.d’EMCI i l’element emprat ha sigut el SOLID65. Aquest element permet introduircaracterístiques de no linealitat en els models i és adequat per a anàlisi no lineald’elements com la pedra de Girona

Relevância:

30.00% 30.00%

Publicador:

Resumo:

2320 composés chimiques ont été screenés à l'aide d'une lignée transgénique de zébrafish. Cette lignée comportait un gène humain fortement exprimé très tôt dans le développement et la croissance de différentes tumeurs, dont celle du rétinoblastome. L'activation de ce gène induisait la mort des embryons de lâ lignée transgénique. Nous avons donc pu identifier des composés agissant sur l'effet létal de ce gène. Cette étude a permis d'isoler plusieurs composés dont 1 très intéressant, l'Amitriptyline. Ce composé induit une inhibition de la prolifération et une induction d'apoptose dans les cellules humaines de rétinoblastome mais également dans d'autres cellules cancéreuses dont les ostéosarcomes connus. L'ostéosarçome est connu pour faire partie des cancers secondaires dû au rétinoblastome dans la forme héréditaire notamment. Ce composé induit la survie des embryons et réduit également le niveau d'expression de la protéine humaine intégrée dans la lignée de poisson zèbre transgénique de 50%. Le niveau d'expression de ce gène est également réduit de 50 à 60% dans des cultures cellulaire de rétinoblastome humain. L'inhibition de la prolifération a été démontrée par la réduction d'ATP dans plusieurs lignées cellulaires lorsque celles-ci sont traitées avec ce composé. L'induction d'apoptose a été démontrée par induction 10 fois plus élevée des éléments pro-apoptotiques caspase-3 et caspase-7 ainsi que par l'augmentation 10 fois plus élevée d'un élément anti-apoptotique bcl-2. Ces résultats permettent de croire que ce composé pourrait être utilisé pour traiter le rétinoblastome humain. -- Background: Retinoblastoma is a rare malignant tumor. This disease is the most prevalent intraocular cancer in childhood with an incidence of 1 in 15,000 live births. Many therapies are available to treat retinoblastoma, but best treatments are individually selected according to cases. Cryotherapy, thermotherapy, laser therapy including brachytherapy, radiation therapy and chemotherapy are some examples. New drug and new treatments discovery is essential for cancer therapy including retinoblastoma. Purpose: A vertebrate model as zebrafish for retinoblastoma would provide many advantages especially to perform drug screening. The high number of fertilized eggs per mating, the rapidity of extra¬utero development, the available genetic manipulation, the easy manipulations under a microscope, the ability to dispense embryos in 96-well plates and the direct incubation of chemical compounds in fish water are some examples of the advantages. Therefore, we design a transgenic zebrafish carrying a human gene implicated in retinoblastoma development and maintenance. Results: With the small compounds screening, several compounds were isolated. One of these compounds, Amitriptyline demonstrated proliferation inhibition and apoptosis in human retinoblastoma cells, U20S osteosarcoma cells and MBA-231 breast cancer cells. Osteosarcoma is known as secondary cancer due to retinoblastoma. Amitriptyline induced survival in our zebrafish transgenic line and 50% reduction of the integrated gene expression. In retinoblastoma cultured cells, the expression of this gene was also reduced in a range of 50-60 %. Proliferation inhibition was demonstrated by ATP luminescence assay. Apoptosis was demonstrated by a 10-fold induction of caspase-3 and caspase-7, two pro-apoptotic elements and by a 10-fold reduction of bcl-2 anti-apoptotic element. Conclusion: The results suggest that Amitriptyline could be used to treat human retinoblastoma in the near future.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND: The evidence base for the diagnosis and management of amyotrophic lateral sclerosis (ALS) is weak. OBJECTIVES: To provide evidence-based or expert recommendations for the diagnosis and management of ALS based on a literature search and the consensus of an expert panel. METHODS: All available medical reference systems were searched, and original papers, meta-analyses, review papers, book chapters and guidelines recommendations were reviewed. The final literature search was performed in February 2011. Recommendations were reached by consensus. RECOMMENDATIONS: Patients with symptoms suggestive of ALS should be assessed as soon as possible by an experienced neurologist. Early diagnosis should be pursued, and investigations, including neurophysiology, performed with a high priority. The patient should be informed of the diagnosis by a consultant with a good knowledge of the patient and the disease. Following diagnosis, the patient and relatives/carers should receive regular support from a multidisciplinary care team. Medication with riluzole should be initiated as early as possible. Control of symptoms such as sialorrhoea, thick mucus, emotional lability, cramps, spasticity and pain should be attempted. Percutaneous endoscopic gastrostomy feeding improves nutrition and quality of life, and gastrostomy tubes should be placed before respiratory insufficiency develops. Non-invasive positive-pressure ventilation also improves survival and quality of life. Maintaining the patient's ability to communicate is essential. During the entire course of the disease, every effort should be made to maintain patient autonomy. Advance directives for palliative end-of-life care should be discussed early with the patient and carers, respecting the patient's social and cultural background.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

High-resolution tomographic imaging of the shallow subsurface is becoming increasingly important for a wide range of environmental, hydrological and engineering applications. Because of their superior resolution power, their sensitivity to pertinent petrophysical parameters, and their far reaching complementarities, both seismic and georadar crosshole imaging are of particular importance. To date, corresponding approaches have largely relied on asymptotic, ray-based approaches, which only account for a very small part of the observed wavefields, inherently suffer from a limited resolution, and in complex environments may prove to be inadequate. These problems can potentially be alleviated through waveform inversion. We have developed an acoustic waveform inversion approach for crosshole seismic data whose kernel is based on a finite-difference time-domain (FDTD) solution of the 2-D acoustic wave equations. This algorithm is tested on and applied to synthetic data from seismic velocity models of increasing complexity and realism and the results are compared to those obtained using state-of-the-art ray-based traveltime tomography. Regardless of the heterogeneity of the underlying models, the waveform inversion approach has the potential of reliably resolving both the geometry and the acoustic properties of features of the size of less than half a dominant wavelength. Our results do, however, also indicate that, within their inherent resolution limits, ray-based approaches provide an effective and efficient means to obtain satisfactory tomographic reconstructions of the seismic velocity structure in the presence of mild to moderate heterogeneity and in absence of strong scattering. Conversely, the excess effort of waveform inversion provides the greatest benefits for the most heterogeneous, and arguably most realistic, environments where multiple scattering effects tend to be prevalent and ray-based methods lose most of their effectiveness.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The prediction of binding modes (BMs) occurring between a small molecule and a target protein of biological interest has become of great importance for drug development. The overwhelming diversity of needs leaves room for docking approaches addressing specific problems. Nowadays, the universe of docking software ranges from fast and user friendly programs to algorithmically flexible and accurate approaches. EADock2 is an example of the latter. Its multiobjective scoring function was designed around the CHARMM22 force field and the FACTS solvation model. However, the major drawback of such a software design lies in its computational cost. EADock dihedral space sampling (DSS) is built on the most efficient features of EADock2, namely its hybrid sampling engine and multiobjective scoring function. Its performance is equivalent to that of EADock2 for drug-like ligands, while the CPU time required has been reduced by several orders of magnitude. This huge improvement was achieved through a combination of several innovative features including an automatic bias of the sampling toward putative binding sites, and a very efficient tree-based DSS algorithm. When the top-scoring prediction is considered, 57% of BMs of a test set of 251 complexes were reproduced within 2 Å RMSD to the crystal structure. Up to 70% were reproduced when considering the five top scoring predictions. The success rate is lower in cross-docking assays but remains comparable with that of the latest version of AutoDock that accounts for the protein flexibility. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Only half of hypertensive patients has controlled blood pressure. Chronic kidney disease (CKD) is also associated with low blood pressure control, 25-30% of CKD patients achieving adequate blood pressure. The Community Preventive Services Task Force has recently recommended team-based care to improve blood pressure control. Team-based care of hypertension involves facilitating coordination of care among physician, pharmacist and nurse and requires sharing clinical data, laboratory results, and medications, e.g., electronically or by fax. Based on recent studies, development and evaluation of team-based care of hypertensive patients should be done in the Swiss healthcare system.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Arsenic contamination of natural waters is a worldwide concern, as the drinking water supplies for large populations can have high concentrations of arsenic. Traditional techniques to detect arsenic in natural water samples can be costly and time-consuming; therefore, robust and inexpensive methods to detect arsenic in water are highly desirable. Additionally, methods for detecting arsenic in the field have been greatly sought after. This article focuses on the use of bacteria-based assays as an emerging method that is both robust and inexpensive for the detection of arsenic in groundwater both in the field and in the laboratory. The arsenic detection elements in bacteria-based bioassays are biosensor-reporter strains; genetically modified strains of, e.g., Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Rhodopseudomonas palustris. In response to the presence of arsenic, such bacteria produce a reporter protein, the amount or activity of which is measured in the bioassay. Some of these bacterial biosensor-reporters have been successfully utilized for comparative in-field analyses through the use of simple solution-based assays, but future methods may concentrate on miniaturization using fiberoptics or microfluidics platforms. Additionally, there are other potential emerging bioassays for the detection of arsenic in natural waters including nematodes and clams.