Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088879
Carla F Santos, M. Parente, J. Belinha, R. Jorge, F. Gentil
The aim of this work is to contribute to a better understanding on how the vestibular system works. This knowledge will help in the development of new techniques that will facilitate a more efficient rehabilitation. Vestibular rehabilitation consists in a set of exercises, known as maneuvers, which can reduce and even eliminate the symptoms of dizziness and imbalance associated with a vestibular disorder. In this work, a three-dimensional model of the vestibular system, containing the fluids which promote the body balance, will be used. One of the aims is to simulate the fluid behaviour and the study of its interaction with the soft tissues of the vestibular structure. This model will allow the simulation of the maneuvers of the vestibular rehabilitation in order to improve its results and the quality of life of patients suffering from vertigo.
{"title":"Numerical simulation of the maneuvers performed in vestibular rehabilitation","authors":"Carla F Santos, M. Parente, J. Belinha, R. Jorge, F. Gentil","doi":"10.1109/ENBENG.2015.7088879","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088879","url":null,"abstract":"The aim of this work is to contribute to a better understanding on how the vestibular system works. This knowledge will help in the development of new techniques that will facilitate a more efficient rehabilitation. Vestibular rehabilitation consists in a set of exercises, known as maneuvers, which can reduce and even eliminate the symptoms of dizziness and imbalance associated with a vestibular disorder. In this work, a three-dimensional model of the vestibular system, containing the fluids which promote the body balance, will be used. One of the aims is to simulate the fluid behaviour and the study of its interaction with the soft tissues of the vestibular structure. This model will allow the simulation of the maneuvers of the vestibular rehabilitation in order to improve its results and the quality of life of patients suffering from vertigo.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127017052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088853
Bruno Ribeiro, Hugo Pereira, R. Almeida, Adelaide Ferreira, Leonardo Martins, C. Quaresma, Pedro Vieira
In a precursory work, an intelligent sensing chair prototype was developed to classify 12 standardized sitting postures using 8 pneumatic bladders (4 in the chair's seat and 4 in the backrest) connected to piezoelectric sensors to measure inner pressure. A Classification of around 80% was obtained using Neural Networks. This work aims to demonstrate how algorithmic optimization can be applied to a newly developed prototype to improve posture classification performance. The aforementioned optimization is based on the split of users by sex and use two different previously trained Neural Networks (one for Male and the other for Female). Results showed that the best neural network parameters had an overall classification 89.0% (from the 92.1% for Female Classification and 85.8% for Male, which translates into an overall optimization of around 8%). Automatic separation of these sets was achieved with Decision Trees with an overall classification optimization of 87.1%.
{"title":"Optimization of sitting posture classification based on user identification","authors":"Bruno Ribeiro, Hugo Pereira, R. Almeida, Adelaide Ferreira, Leonardo Martins, C. Quaresma, Pedro Vieira","doi":"10.1109/ENBENG.2015.7088853","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088853","url":null,"abstract":"In a precursory work, an intelligent sensing chair prototype was developed to classify 12 standardized sitting postures using 8 pneumatic bladders (4 in the chair's seat and 4 in the backrest) connected to piezoelectric sensors to measure inner pressure. A Classification of around 80% was obtained using Neural Networks. This work aims to demonstrate how algorithmic optimization can be applied to a newly developed prototype to improve posture classification performance. The aforementioned optimization is based on the split of users by sex and use two different previously trained Neural Networks (one for Male and the other for Female). Results showed that the best neural network parameters had an overall classification 89.0% (from the 92.1% for Female Classification and 85.8% for Male, which translates into an overall optimization of around 8%). Automatic separation of these sets was achieved with Decision Trees with an overall classification optimization of 87.1%.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116064932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088808
A. C. Ribeiro, L. Fonseca, R. Soares, N. D. da Silveira, G. L. Peres
Amylose is a linear polymer composed almost entirely of α-1,4-linked units. This biopolymer tends to form single helical inclusion complexes with suitable agents. The study of these complexes presents a great interest since the guest molecules that have been trapped at some stage can be release later, thus leading to many applications, especially in the pharmaceutical and food industry. Amylose is considered as a promising carrier biomaterial of prodrugs [1]. Pyrazinamide (PZA) has long been recognized as an active drug against Mycobacterium tuberculosis, however the administration of PZA in high dosage can cause bacterial resistance. Therefore there is a need for new methodologies which would reduce the administration time and improve therapeutic effect of PZA [2]. The aim of our study was to characterize the amylose-PZA complex. The inclusion complex was prepared by acidification of an alkali solution. Formation and characterization (particle size) of the inclusion complexes in solution were characterized by dynamic light scattering and UV spectroscopy. As the complexation causes changes in the absorption spectrum of a guest molecule, change in the colour of the solution from yellow to colourless was noticed. Furthermore, differences in intensity of the bands, and a slight shift of the absorption spectrum of inclusion complexes, in comparison with the pure amylose solution were observed. The UV analyses confirmed the formation of the amylose-PZA inclusion complexes. DLS analysis has been made for: complexes with pure amylose (without PZA), with PZA (without amylose) and amylose-PZA complexes. The amylose particle size, without the guest molecule, was (101,16±2,60) nm and its relative average poly dispersity index was 0,41±0,04. For the PZA particle the size was (223,70±13,76) nm and its relative average polydispersity index was 0,27±0,10. On the other hand for the amylose-PZA inclusion complexes the size (81,11±1,43) nm was observed and its relative average polydispersity index was 0,26±0,02. As can be seen the size of the complex is smaller than of the pure amylose or PZA particle in solution. This can be attributed to the presence of PZA that induces hydrophobic interactions resulting in the contraction of the complexes and providing a relatively hydrophilic surface. Furthermore, PDI results also indicated that sizes generated from inclusion complexes have a narrow size distribution. Thus, new analysis tests will be conducted to provide more information about structure and morphology of inclusion complexes.
{"title":"Preparation and characterization of amylose-pyrazinamide inclusion complexes","authors":"A. C. Ribeiro, L. Fonseca, R. Soares, N. D. da Silveira, G. L. Peres","doi":"10.1109/ENBENG.2015.7088808","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088808","url":null,"abstract":"Amylose is a linear polymer composed almost entirely of α-1,4-linked units. This biopolymer tends to form single helical inclusion complexes with suitable agents. The study of these complexes presents a great interest since the guest molecules that have been trapped at some stage can be release later, thus leading to many applications, especially in the pharmaceutical and food industry. Amylose is considered as a promising carrier biomaterial of prodrugs [1]. Pyrazinamide (PZA) has long been recognized as an active drug against Mycobacterium tuberculosis, however the administration of PZA in high dosage can cause bacterial resistance. Therefore there is a need for new methodologies which would reduce the administration time and improve therapeutic effect of PZA [2]. The aim of our study was to characterize the amylose-PZA complex. The inclusion complex was prepared by acidification of an alkali solution. Formation and characterization (particle size) of the inclusion complexes in solution were characterized by dynamic light scattering and UV spectroscopy. As the complexation causes changes in the absorption spectrum of a guest molecule, change in the colour of the solution from yellow to colourless was noticed. Furthermore, differences in intensity of the bands, and a slight shift of the absorption spectrum of inclusion complexes, in comparison with the pure amylose solution were observed. The UV analyses confirmed the formation of the amylose-PZA inclusion complexes. DLS analysis has been made for: complexes with pure amylose (without PZA), with PZA (without amylose) and amylose-PZA complexes. The amylose particle size, without the guest molecule, was (101,16±2,60) nm and its relative average poly dispersity index was 0,41±0,04. For the PZA particle the size was (223,70±13,76) nm and its relative average polydispersity index was 0,27±0,10. On the other hand for the amylose-PZA inclusion complexes the size (81,11±1,43) nm was observed and its relative average polydispersity index was 0,26±0,02. As can be seen the size of the complex is smaller than of the pure amylose or PZA particle in solution. This can be attributed to the presence of PZA that induces hydrophobic interactions resulting in the contraction of the complexes and providing a relatively hydrophilic surface. Furthermore, PDI results also indicated that sizes generated from inclusion complexes have a narrow size distribution. Thus, new analysis tests will be conducted to provide more information about structure and morphology of inclusion complexes.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125688731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088881
T. Atalaia, J. Abrantes
Footedness is the preferable use of one lower limb in respect to it contralateral one. Hypothetically, stability should demonstrate such differences. Transferring this concept into human motor skills, different adaptations of stiffness measures are applied as an indicator of dynamic joint stiffness, vertical stiffness and leg stiffness. Footedness influence was assessed in three different tasks used in rehabilitation and sports: gait, single-leg triple jump for distance and unilateral hopping. Kinematic and synchronized kinetic data was obtained by a 3D motion analysis system and a force platform. Results indicate no differences between dominant and non-dominant limb, exception to the concentric sub phase of the unilateral hopping stance phase, on ankle's dynamic joint stiffness (p<;0,05). Discussion increase the lack of definition consensus of dominant lower limb and strengths the theory of inexistent lower limb dominance.
{"title":"Footedness influence on stability measures","authors":"T. Atalaia, J. Abrantes","doi":"10.1109/ENBENG.2015.7088881","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088881","url":null,"abstract":"Footedness is the preferable use of one lower limb in respect to it contralateral one. Hypothetically, stability should demonstrate such differences. Transferring this concept into human motor skills, different adaptations of stiffness measures are applied as an indicator of dynamic joint stiffness, vertical stiffness and leg stiffness. Footedness influence was assessed in three different tasks used in rehabilitation and sports: gait, single-leg triple jump for distance and unilateral hopping. Kinematic and synchronized kinetic data was obtained by a 3D motion analysis system and a force platform. Results indicate no differences between dominant and non-dominant limb, exception to the concentric sub phase of the unilateral hopping stance phase, on ankle's dynamic joint stiffness (p<;0,05). Discussion increase the lack of definition consensus of dominant lower limb and strengths the theory of inexistent lower limb dominance.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116382537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088832
F. G. Guerra Liberal, R. S. Tavares Joao Manuel, A. Tavares
Throughout the years, the palliative treatment of bone metastases using bone seeking radiotracers has been part of the therapeutic resources used in oncology. However, the choice of which bone seeking agent to use is not consensual. Computer simulation is a simple and practical solution to study and to compare a variety of radioisotopes. This study aimed to compare 11 different radioisotopes currently in use or under research. Hence, computational models were used to estimate the percentage of deoxyribonucleic acid damage, the probability of correct DNA repair, and the radiation-induced cellular effects post-irradiation. 223Ra alpha particles, 177Lu beta minus particles, and 170Tm beta minus particles induced the highest cell death of all investigated particles and radioisotopes. The cell survival fraction measured post-irradiation with beta minus particles emitted by 89Sr and 153Sm, was higher than 177Lu beta minus particles and 223Ra alpha particles. Findings reported here may prompt future in vitro and in vivo experiments comparing different radionuclides for palliative treatment of bone metastases.
{"title":"In silico comparasion of 11 different radioisotopes for palliative treatment of bone metastases","authors":"F. G. Guerra Liberal, R. S. Tavares Joao Manuel, A. Tavares","doi":"10.1109/ENBENG.2015.7088832","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088832","url":null,"abstract":"Throughout the years, the palliative treatment of bone metastases using bone seeking radiotracers has been part of the therapeutic resources used in oncology. However, the choice of which bone seeking agent to use is not consensual. Computer simulation is a simple and practical solution to study and to compare a variety of radioisotopes. This study aimed to compare 11 different radioisotopes currently in use or under research. Hence, computational models were used to estimate the percentage of deoxyribonucleic acid damage, the probability of correct DNA repair, and the radiation-induced cellular effects post-irradiation. 223Ra alpha particles, 177Lu beta minus particles, and 170Tm beta minus particles induced the highest cell death of all investigated particles and radioisotopes. The cell survival fraction measured post-irradiation with beta minus particles emitted by 89Sr and 153Sm, was higher than 177Lu beta minus particles and 223Ra alpha particles. Findings reported here may prompt future in vitro and in vivo experiments comparing different radionuclides for palliative treatment of bone metastases.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114109193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088859
M. Zamith, P. Mendes
Misplacement of surgical instruments inside an operating room is a frequent mistake that can bring unnecessary complications. We propose a system that can prevent these, through wireless communication. In this paper, we investigate the use of the 55-60 GHz band in the implementation of a RFID system that presents very interesting characteristics like improved security and small size. From the measurements already made, it's expected the RFID system operating in the 60 GHz ISM will work at distances, at least, up to 5 meters. Furthermore, it is proposed a solution to obtain a fully integrated system based on an on-chip antenna that could be integrated with an RF CMOS chip based on 65 nm CMOS technology.
{"title":"Towards an RFID microsystem for surgical instrument detection using millimeter waves","authors":"M. Zamith, P. Mendes","doi":"10.1109/ENBENG.2015.7088859","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088859","url":null,"abstract":"Misplacement of surgical instruments inside an operating room is a frequent mistake that can bring unnecessary complications. We propose a system that can prevent these, through wireless communication. In this paper, we investigate the use of the 55-60 GHz band in the implementation of a RFID system that presents very interesting characteristics like improved security and small size. From the measurements already made, it's expected the RFID system operating in the 60 GHz ISM will work at distances, at least, up to 5 meters. Furthermore, it is proposed a solution to obtain a fully integrated system based on an on-chip antenna that could be integrated with an RF CMOS chip based on 65 nm CMOS technology.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116158346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088820
R. Loução, R. Nunes, Rafael Neto-Henriques, M. Correia, H. Ferreira
Water diffusion can be measured using Diffusion Tensor Imaging (DTI). This technique estimates molecular diffusion using a Gaussian model which can account for anisotropy arising, for example, from the presence of myelin sheath. The main direction of diffusion can also be estimated from DTI and used to compute diffusion tracts (tractography), a good tool to analyse the structure of white matter brain pathways. Nevertheless, DTI has limitations, such as ignoring the non-Gaussian properties of biological tissues and the inability to resolve intra-voxel fibre crossings that may lead to the reconstruction of anatomically inaccurate tracts. Diffusion Kurtosis Imaging (DKI) was introduced to ameliorate these problems. By abandoning the Gaussian model, DKI acts as an extension of DTI, allowing the computation of the same scalar parameters as DTI as well as providing measures of tissue heterogeneity and resolving multiple tracts within each voxel[1]. The purpose of this study is to analyse the DKI performance in tractography comparing to the DTI approach. DKI data was acquired from 3 subjects (1 male, mean age: 39±14 years) using Philips Achieva® 3.0T including diffusion weighted (DW) Single Shot Echo Planar images using 64 directions with b-values 0, 1000 and 2000 s/mm2, reconstruction matrix 256×256, slice thickness 1.5 mm, TE/TR 64/7703 ms, FOV 240×240 mm2, 60 slices. DTI data was extracted from DKI considering only b-values 0 and 1000. All DTI and DKI based tracts were computed using DKIu, a Matlab toolbox created by Neto-Henriques et. al., using three different tractography approaches: DTI, Laz-DKI[2] and KT-DKI[1]. The structures considered were the Internal Capsule (IC) and the Corpus Callosum (CC). Using TrackVis for visualisation, DKI tractography was shown to enable improved fibre crossing resolutio n (Figure 1), consistent in all three subjects. The number of streamlines computed in the CC was higher with the DKI approach than with DTI, but lower in the IC. DKI-based tractography appears to successfully address some of the limitations of DTI, as it resolves crossing fibres, providing more useful information regarding the brain's microstructure. This is particularly important in pre-surgical planning and in identifying brain lesions and pathologies.
水的扩散可以用扩散张量成像(DTI)来测量。这种技术使用高斯模型来估计分子扩散，这种模型可以解释各向异性的产生，例如，髓鞘的存在。扩散的主要方向也可以从DTI估计，并用于计算扩散束(束图)，一个很好的工具，分析白质脑通路的结构。然而，DTI也有局限性，比如忽略了生物组织的非高斯特性，无法解决体素内纤维交叉，这可能导致解剖学上不准确的束重建。扩散峰度成像(DKI)的引入改善了这些问题。通过放弃高斯模型，DKI作为DTI的扩展，允许计算与DTI相同的标量参数，并提供组织异质性的度量和解决每个体素内的多个域[1]。本研究的目的是分析DKI在牵道造影中的表现与DTI方法的比较。DKI数据来自3名受试者(1名男性，平均年龄39±14岁)，使用Philips Achieva®3.0T包括64个方向的扩散加权(DW)单次回波平面图像，b值分别为0、1000和2000 s/mm2，重建矩阵256×256，切片厚度1.5 mm, TE/TR 64/7703 ms，视场240×240 mm2, 60片。DTI数据从DKI中提取，仅考虑b值0和1000。使用Neto-Henriques等人创建的Matlab工具箱DKIu计算所有基于DTI和DKI的束，使用三种不同的束道成像方法:DTI、Laz-DKI[2]和KT-DKI[1]。考虑的结构是内囊(IC)和胼胝体(CC)。使用TrackVis进行可视化，DKI牵束成像显示可以提高纤维交叉分辨率n(图1)，这在所有三个受试者中都是一致的。DKI方法在CC中计算的流线数量比DTI方法高，但在IC中较低。基于DKI的束束造影似乎成功地解决了DTI的一些局限性，因为它解决了交叉纤维，提供了更多关于大脑微观结构的有用信息。这在术前计划和识别脑部病变和病理方面尤为重要。
{"title":"Human brain tractography: A DTI vs DKI comparison analysis","authors":"R. Loução, R. Nunes, Rafael Neto-Henriques, M. Correia, H. Ferreira","doi":"10.1109/ENBENG.2015.7088820","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088820","url":null,"abstract":"Water diffusion can be measured using Diffusion Tensor Imaging (DTI). This technique estimates molecular diffusion using a Gaussian model which can account for anisotropy arising, for example, from the presence of myelin sheath. The main direction of diffusion can also be estimated from DTI and used to compute diffusion tracts (tractography), a good tool to analyse the structure of white matter brain pathways. Nevertheless, DTI has limitations, such as ignoring the non-Gaussian properties of biological tissues and the inability to resolve intra-voxel fibre crossings that may lead to the reconstruction of anatomically inaccurate tracts. Diffusion Kurtosis Imaging (DKI) was introduced to ameliorate these problems. By abandoning the Gaussian model, DKI acts as an extension of DTI, allowing the computation of the same scalar parameters as DTI as well as providing measures of tissue heterogeneity and resolving multiple tracts within each voxel[1]. The purpose of this study is to analyse the DKI performance in tractography comparing to the DTI approach. DKI data was acquired from 3 subjects (1 male, mean age: 39±14 years) using Philips Achieva® 3.0T including diffusion weighted (DW) Single Shot Echo Planar images using 64 directions with b-values 0, 1000 and 2000 s/mm2, reconstruction matrix 256×256, slice thickness 1.5 mm, TE/TR 64/7703 ms, FOV 240×240 mm2, 60 slices. DTI data was extracted from DKI considering only b-values 0 and 1000. All DTI and DKI based tracts were computed using DKIu, a Matlab toolbox created by Neto-Henriques et. al., using three different tractography approaches: DTI, Laz-DKI[2] and KT-DKI[1]. The structures considered were the Internal Capsule (IC) and the Corpus Callosum (CC). Using TrackVis for visualisation, DKI tractography was shown to enable improved fibre crossing resolutio n (Figure 1), consistent in all three subjects. The number of streamlines computed in the CC was higher with the DKI approach than with DTI, but lower in the IC. DKI-based tractography appears to successfully address some of the limitations of DTI, as it resolves crossing fibres, providing more useful information regarding the brain's microstructure. This is particularly important in pre-surgical planning and in identifying brain lesions and pathologies.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124758076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088833
Stéphanie Andrade, J. Loureiro, M. Coelho, Maria do Carmo Pereira
The amyloid cascade hypothesis suggests that dysfunction and neuronal death in the brain is caused by the deposition of amyloid beta-peptide (Aβ) in the Alzheimer's disease (AD). The peptide is aggregated as amyloid fibrils within the neuritic plaques and vascular deposits that characterize the disease. Thus, it is essential to find molecules that prevent or interrupt this aggregation process. Various natural compounds have been suggested as therapeutics for AD. Among these compounds, resveratrol (RES) arouses great interest in the therapy of AD. In this study the structure and fibril assembly of the Aβ(1-42) were analyzed in the presence of different sources of RES. The results demonstrated that Aβ(1-42) forms fibrils with different morphologies depending on the RES provenience. Moreover, TEM analysis and Thioflavin T fluorescence assay suggest that the presence of the resveratrol present in the grape skin retards or even inhibits the aggregation of the peptide.
{"title":"Interaction studies of amyloid beta-peptide with the natural compound resveratrol","authors":"Stéphanie Andrade, J. Loureiro, M. Coelho, Maria do Carmo Pereira","doi":"10.1109/ENBENG.2015.7088833","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088833","url":null,"abstract":"The amyloid cascade hypothesis suggests that dysfunction and neuronal death in the brain is caused by the deposition of amyloid beta-peptide (Aβ) in the Alzheimer's disease (AD). The peptide is aggregated as amyloid fibrils within the neuritic plaques and vascular deposits that characterize the disease. Thus, it is essential to find molecules that prevent or interrupt this aggregation process. Various natural compounds have been suggested as therapeutics for AD. Among these compounds, resveratrol (RES) arouses great interest in the therapy of AD. In this study the structure and fibril assembly of the Aβ(1-42) were analyzed in the presence of different sources of RES. The results demonstrated that Aβ(1-42) forms fibrils with different morphologies depending on the RES provenience. Moreover, TEM analysis and Thioflavin T fluorescence assay suggest that the presence of the resveratrol present in the grape skin retards or even inhibits the aggregation of the peptide.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121251129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088868
Â. Araújo, N. Peixinho, A. Pinho, J. Claro
The study of mechanical properties of intervertebral disc (IVD) is important for the evaluation of disc implants. To determine these properties, several animal spine models were used. The goal of this work is to determine and compare the dynamic stiffness coefficient (Kd) and initial creep behavior of porcine intervertebral disc with the human ones. Porcine lumbar “motion segments” were subjected to 1200 cycles of axial compressive loading at 1 Hz, and a mean load of 500 N. The results were fitted with a mathematical model. The Kd values are in same magnitude as the previously reported for human. The model showed a good adjust to the initial creep behavior and the obtained parameters present the same magnitude as the human discs, with exception of time constant. This work revealed that porcine MS is an interesting model to study both the dynamic behavior and initial creep response of human disc.
{"title":"Comparison between the dynamic and initial creep response of porcine and human lumbar intervertebral discs","authors":"Â. Araújo, N. Peixinho, A. Pinho, J. Claro","doi":"10.1109/ENBENG.2015.7088868","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088868","url":null,"abstract":"The study of mechanical properties of intervertebral disc (IVD) is important for the evaluation of disc implants. To determine these properties, several animal spine models were used. The goal of this work is to determine and compare the dynamic stiffness coefficient (Kd) and initial creep behavior of porcine intervertebral disc with the human ones. Porcine lumbar “motion segments” were subjected to 1200 cycles of axial compressive loading at 1 Hz, and a mean load of 500 N. The results were fitted with a mathematical model. The Kd values are in same magnitude as the previously reported for human. The model showed a good adjust to the initial creep behavior and the obtained parameters present the same magnitude as the human discs, with exception of time constant. This work revealed that porcine MS is an interesting model to study both the dynamic behavior and initial creep response of human disc.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129355088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-02-01DOI: 10.1109/ENBENG.2015.7088834
M. G. Fernandes, R. Natal, E. Fonseca
In this study, a three-dimensional dynamic model was built to simulate the drilling process in the composite materials. With an explicit dynamic simulation it is possible to obtain large structural deformation and to apply high intensity loading in a short time frame. Using this methodology, the influence of different cutting parameters were considered during the drilling process in typical composite materials. Also, similar tests were produced in laboratory using composite blocks. Each composite material was instrumented with strain gauges to obtain the strain in different surface positions during the drilling process. The results from the numerical methodology were compared with the experimental methodology. It was concluded when the feed-rate is higher the stresses and strains in the composite material are lower. The obtained numerical and experimental results were similar. Therefore the developed numerical model proved to be a great tool in this kind of analysis.
{"title":"Analysis of stresses in drilled composite materials","authors":"M. G. Fernandes, R. Natal, E. Fonseca","doi":"10.1109/ENBENG.2015.7088834","DOIUrl":"https://doi.org/10.1109/ENBENG.2015.7088834","url":null,"abstract":"In this study, a three-dimensional dynamic model was built to simulate the drilling process in the composite materials. With an explicit dynamic simulation it is possible to obtain large structural deformation and to apply high intensity loading in a short time frame. Using this methodology, the influence of different cutting parameters were considered during the drilling process in typical composite materials. Also, similar tests were produced in laboratory using composite blocks. Each composite material was instrumented with strain gauges to obtain the strain in different surface positions during the drilling process. The results from the numerical methodology were compared with the experimental methodology. It was concluded when the feed-rate is higher the stresses and strains in the composite material are lower. The obtained numerical and experimental results were similar. Therefore the developed numerical model proved to be a great tool in this kind of analysis.","PeriodicalId":285567,"journal":{"name":"2015 IEEE 4th Portuguese Meeting on Bioengineering (ENBENG)","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115159965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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