38 research outputs found
Comparison the concepts of sense of place and attachment to place in architectural studies
Today, concepts such as place attachment, sense of place, meaning of place, place identity, and ... has devoted many studies In literature of architecture and urban design particularly in the field of environmental psychology. It is obvious that in all these concepts, various aspects of interaction between human and place and the impact that places have on people has been presented. This paper defines the concepts of sense of place and place attachment and explains the factors that affect them. Sense of place is a comprehensive concept which in it men feels places, percept them and attached meaning to them. Understanding the fundamental aspects of sense of place, can be effective in assess the level of public attachment to places and tendency of people to places. Place attachment refer to emotional and functional bonds between place and people which Interpreted in different scale from a district to a country in Environmental psychology. In this regard different studies point to varied of spatial and human factors. Review the literature, this paper achieves a comprehensive definition of these concepts and then it try to compare them to find their relationship. What will come eventually is that place attachment is one of the sense of place subsets. Thus in encounter of people and place if assume people sense of place a general feeling to that place, place attachment is a positive emotion which people have about the place
Abnormal Tissue Zone Detection and Average Active Stress Estimation in Patients with LV Dysfunction
Detection of regional ventricular dysfunction is a challenging problem. This study presents an efficient method based on ultrasound (US) imaging and finite element (FE) analysis, for detecting akinetic and dyskinetic regions in the left ventricle (LV). The underlying hypothesis is that the contraction of a healthy LV is approximately homogeneous. Therefore, any deviations between the image-based measured deformation and a homogeneous contraction FE model should correspond to a pathological region. The method was first successfully applied to synthetic data simulating an acute ischemia; it demonstrated that the pathological areas were revealed with a higher contrast than those observed directly in the deformation maps. The technique was then applied to a cohort of eight left bundle branch block (LBBB) patients. For this group, the heterogeneities were significantly less pronounced than those revealed for the synthetic cases but the method was still able to identify the abnormal regions of the LV. This study indicated the potential clinical utility of the method by its simplicity in a patient-specific context and its ability to quickly identify various heterogeneities in LV function. Further studies are required to determine the model accuracy in other pathologies and to investigate its robustness to noise and image artifacts
scontribution à l’évolution de la contrainte patient-spécifique dans le ventricule gauche humain par analyse éléments finis à partir d’images médicales
Mechanical stresses in the left ventricle of the heart may present abnormalities which gradually can result in heart failure. It is therefore important to be able to rebuild accurately this behaviour in order to understand, analyse, diagnose and treat cardiac dysfunction. In this context, personalized or patient-specific finite element simulations of the heart are of a great interest, but there remain several challenges in clinical routine accessibility. It is essential to bear in mind that no imaging method allows access to the mechanical properties of the cardiac tissue or the state of residual stresses of each patient. These two data are necessary to reconstruct the stress fields in the heart using state of the art. In this thesis, we have worked on two problems: 1. The stress field in the cardiac tissue can be predicted by the finite element models but it requires precise determination of the tissue’s mechanical properties. Some models require more than 11 values to be determined, therefore, it is not realistic to identify these parameters for each individual. The question is, therefore: Is it possible to reconstruct the stress field in cardiac tissue given the uncertainty of the mechanical properties? It is thus shown that for several constitutive models, the stress dependency on the parameters is low. 2. Mechanical models often require high spatial resolution imaging data to reconstruct the stress maps in the tissue which leads the imaging modality towards MRI, even if it is an expensive modality. Our second question is: Is it possible to use ultrasound data to meet the same goals in case of patients suffering from cardiac pathologies? To answer, a fast and efficient automatic mesh morphing algorithm is introduced to generate hexahedral fine meshes for patients’ coarse geometries obtained from echocardiography. In addition to this automatic mesh generation pipeline, we developed a method to detect the infarct zone as well as estimating an average active contraction value expressing the state of the tissue activity during systolic phase. This algorithm has been successful to detect the abnormal tissue zone in acute ischemia case. Following, it was applied to a cohort of 8 patients suffering from left bundle branch block obtained from GE Healthcare’s ultrasound system, treated by resynchronization therapy.Les contraintes mécaniques dans le ventricule gauche du cœur peuvent présenter des anomalies en cas d'insuffisance cardiaque et il est donc important de pouvoir les reconstruire précisément pour comprendre, analyser, diagnostiquer et traiter une dysfonction cardiaque. Dans ce contexte, les calculs personnalisés ou patient-spécifiques par la méthode des éléments finis dans le cœur présentent un fort intérêt, mais il subsiste plusieurs défis pour les diffuser jusqu’à la clinique, à savoir qu’aucune méthode d’imagerie ne permet d’accéder aux propriétés mécaniques du tissu cardiaque ou à l’état de contraintes résiduelles de chaque patient. Ces deux données sont pourtant requises pour reconstruire les champs de contraintes dans le cœur en utilisant l’état de l’art. Dans cette thèse, afin de contribuer à la résolution de cette problématique, nous avons travaillé sur deux problèmes: 1. le champ de contrainte dans le tissu cardiaque peut être prédit par les modèles par éléments finis mais cela requiert de déterminer précisément les propriétés mécaniques du tissu. Certains modèles nécessitent plus de 11 valeurs à déterminer, ce qu’il n’est pas réaliste de vouloir identifier à l’échelle de chaque individu. La question est donc : est-il possible de reconstruire le champ de contrainte dans le tissu cardiaque dans un contexte d’incertitude sur les propriétés mécaniques ? Il est alors montré que pour plusieurs modèles de comportement, la dépendance des contraintes aux paramètres est faible. 2. Les modèles mécaniques nécessitent souvent des données d’imagerie de très haute résolution spatiale pour pouvoir reconstruire les cartes de contraintes dans le tissu, ce qui oriente la modalité l’imagerie vers l’IRM. Or il s’agit d’une modalité couteuse. Notre seconde question est donc : est-il possible d’exploiter des données d’échographie pour attendre les mêmes objectifs pour les patients ? Pour y répondre, nous avons introduit une nouvelle méthode de morphing de maillage éléments finis. A partir d’un maillage héxaèdres de référence de haute résolution, un maillage du ventricule gauche de chaque patient a été obtenu par morphing sur les images échographiques. Ensuite, nous avons développé une méthode pour détecter une éventuelle zone de tissu infarcté en estimant la valeur de contraction active moyenne exprimant l'état de l'activité tissulaire de chaque patient pendant la phase systolique. Cet algorithme a réussi à détecter la zone anormale des tissus dans le cas d'ischémie aiguë simulée numériquement puis il a été appliqué à une cohorte de 8 patients atteint du bloc de branche gauche et traité par resynchronisation
Develop synergistic strategies for the intelligence component of the Army of the Islamic Republic of Iran in joint operations
The Islamic Republic of Iran is composed of forces that have a separate specialized nature and a different operational space. In every war scene, there are two forces, the insider and the enemy, which have different operational environments, goals, tactics and techniques, so the presence of various equipment and forces with different specialties and even organizational culture to respond to various enemy actions is needed. It has an integrated and network-oriented information system.This system, by creating an integrated information network in information systems and information protection and monitoring future operational areas in order to identify and utilize indigenous capabilities, will synergize the planning, implementation, control and monitoring of joint operations of the four forces of the army.The main purpose of this research is to enumerate the environmental factors that play a role and to formulate synergistic strategies of the military information system in joint operations. The sample population is 74 people and the method of collecting field and library information is. The findings were analyzed using SPSS.Based on the research results, 18 role-playing factors (5 strengths, 2 weaknesses, 7 opportunities and 4 threats) have been counted. From the combination of the above factors, 12 desirability and 15 challenges have been obtained. According to the calculations, the characteristics of the strategic area are in a strong offensive position, and accordingly, 6 strategies have been developed to synergize the intelligence component of the army in joint operations
Hydrothermal synthesis of fine stabilized superparamagnetic nanoparticles of Zn2+ substituted manganese ferrite
Superparamagnetic Zn2+ substituted manganese ferrite Mn1−xZnxFe2O4 (x=0.3, 0.35, 0.4 and 0.45) nanoparticles (NPs) were synthesized via a direct, efficient and environmental friendly hydrothermal method. The synthesized NPs were characterized by X-ray powder diffractometry (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and vibrating sample magnetometry (VSM). The effects of various parameters such as the pH of reaction mixture, time and temperature of hydrothermal treatment and Zn substitution on the spinel phase formation, the magnetization, and the size of resulting NPs are discussed. The Zn2+ substituted manganese ferrite NPs obtained from hydrothermal process crystallized mainly in the spinel phase. Nevertheless, without citrate ions, the hematite phase appeared in the product. The monophase Zn2+ substituted manganese ferrite NPs hydrothermally prepared in the presence of citric acid had mean particle size of 7 nm and a narrow size distribution. Furthermore, the synthesized NPs can be used to prepare ferrofluids for biomedical applications due to their small size, good stability in aqueous medium (pH 7) and also high magnetization value.This work was supported by Isfahan University of Technology, Iran
Preparation and Characterization of Manganese FerriteNanoparticles via Co-precipitation Method forHyperthermia: Mn ferrite nanoparticles preparation
In this work, Mn ferrite nanopowders were prepared by co-precipitation method and were characterized. Phase identification of the nanopowders was performed by X-ray diffraction method and the mean particle size of the nanopowders was calculated by Scherrer's formula, using necessary corrections. Magnetic parameters of the prepared nanopowders were measured by a vibrating sample magnetometer .Asensitive thermometer was used to measure the increase in temperature due to application of an alternating magnetic field on suspended magnetic nanopowders in water. Transmission electron microscope investigations showed that the particle size distribution was homogeneous and their size was in a good agreement with those obtained by Scherrer's formula. The results show that a single phase Mn ferrite can be obtained by co-precipitation method at 70 °C with a mean particle size of 5 nm and a 5 °C temperature increase is achievable in an AC magnetic field
Use of Magnetic Folate-Dextran-Retinoic Acid Micelles for Dual Targeting of Doxorubicin in Breast Cancer
Amphiphilic copolymer of folate-conjugated dextran/retinoic acid (FA/DEX-RA) was self-assembled into micelles by direct dissolution method. Magnetic iron oxide nanoparticles (MNPs) coated with oleic acid (OA) were prepared by hydrothermal method and encapsulated within the micelles. Doxorubicin HCl was loaded in the magnetic micelles. The characteristics of the magnetic micelles were determined by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The crystalline state of OA-coated MNPs and their heat capacity were analyzed by X-ray diffraction (XRD) and differential scanning calorimetry (DSC) methods, respectively. The iron content of magnetic micelles was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Bovine serum albumin (BSA) was used to test the protein binding of magnetic micelles. The cytotoxicity of doxorubicin loaded magnetic micelles was studied on MCF-7 and MDA-MB-468 cells using MTT assay and their quantitative cellular uptake by fluorimetry method. TEM results showed the MNPs in the hydrophobic core of the micelles. TGA results confirmed the presence of OA and FA/DEX-RA copolymer on the surface of MNPs and micelles, respectively. The magnetic micelles showed no significant protein bonding and reduced the IC50 of the drug to about 10 times lower than the free drug
Importance of material parameters and strain energy function on the wall stresses in the left ventricle
International audienceImportance of material parameters and strain energy function on the wall stresses in the left ventricle Patient-specific estimates of the stress distribution in the left ventricles (LV) may have important applications for therapy planning, but computing the stress generally requires knowledge of the material behaviour. The passive stress-strain relation of myocardial tissue has been characterized by a number of models, but material parameters (MPs) remain difficult to estimate. The aim of this study is to implement a zero-pressure algorithm to reconstruct numerically the stress distribution in the LV without precise knowledge of MPs. We investigate the sensitivity of the stress distribution to variations in the different sets of constitutive parameters. We show that the sensitivity of the LV stresses to MPs can be marginal for an isotropic constitutive model. However, when using a transversely isotropic exponential strain energy function, the LV stresses become sensitive to MPs, especially to the linear elastic coefficient before the exponential function. This indicates that in-vivo identification efforts should focus mostly on this MP for the development of patient-specific finite-element analysis