Retinal optical imaging of intrinsic signals

Une méthode relativement récente qui est utilisée pour étudier l'activité neuronale de façon indirecte désigne l’imagerie optique des signaux intrinsèques. Cette méthode a d’abord été utilisée afin de visualiser l’activité corticale. L'imagerie optique intrinsèque mesure les variations de réflectance de la lumière associées à l'activité du tissu nerveux. Les études au niveau cérébral ont montré que ces changements de réflectance sont attribuables à des changements de volume et de flot sanguin, du niveau d'oxygénation de sang (oxymétrie), et de la dispersion de la lumière. Similairement, les études sur l'application de cette méthode d’imagerie au niveau de la rétine montrent la présence de signaux intrinsèques pendant l'activité rétinienne. Cependant, il apparait que les signaux intrinsèques observés dans la rétine ont leurs propres caractéristiques, étant donné la structure particulière de la rétine. L’origine anatomique de ces signaux intrinsèques est donc encore incertaine. L’imagerie optique intrinsèque rétinienne pourrait présenter un avenir prometteur pour le diagnostic de pathologies oculaires lors de tests cliniques. Toutefois, avant que cette technique puisse être utilisée en clinique, une connaissance détaillée des propriétés et de l'origine des signaux intrinsèques rétiniens est nécessaire. Le premier but de ce projet est d'étudier les réponses intrinsèques rétiniennes pour déterminer les caractéristiques ainsi que l'origine anatomique. Afin d’atteindre cet objectif un système imagerie rétinien (RFI), conçu pour l’œil humain est utilisé. Pour ce système, nous utiliserons le lapin comme modèle animal, car il a des yeux de grandeur comparable aux yeux humains. Plusieurs agents pharmacologiques ont été utilisés pour bloquer les différentes cellules de la rétine afin de déterminer l'origine du signal cellulaire intrinsèque dans lapin. Le deuxième but de ce projet est de développer un système d'imagerie optique des signaux intrinsèques. Ce système est développé pour le modèle de rat. Un agent pharmacologique (Aspartate) est utilisé chez le rat afin de valider ce système imagerie. Nos résultats indiquent que dans la rétine du lapin les cellules bipolaires sont les principales cellules à l’origine des signaux intrinsèques rétiniens. De plus environ 20% des cellules ganglionnaires jouent un rôle dans la genèse des signaux intrinsèques. Nos résultats indiquent aussi qu’il est possible de construire un système d’imagerie efficace pour des petits animaux comme le rat. Les données obtenues avec ce nouveau système confirment que la rétine interne est à l’origine des signaux intrinsèques rétiniens.A relatively new method to study neural activity indirectly is optical imaging of intrinsic signals. This method was first used to visualize cortical activity. The intrinsic optical imaging measures the reflectance variations of light associated with the activity of nervous tissue. Brain studies have shown that these changes in reflectance are attributable to changes in volume, blood flow, blood oxygenation level (oximetry), and light scattering. Similarly, studies on the application of this imaging method to the retina show the presence of intrinsic signals during retinal activity. It appears that the intrinsic signals observed in the retina have their own characteristics, given the particular structure of the retina. The anatomical origins of these intrinsic signals are still uncertain. Retinal intrinsic optical imaging may provide a promising future for the diagnosis of eye diseases in clinical trials. Thus, before this technique can be used clinically, a detailed knowledge of the properties and origin of intrinsic signals are needed. The first goal of this project is to study the retinal intrinsic responses to determine the characteristics and its anatomic origin. To achieve this aim, the retinal imaging system (RFI), designed for the human eye is used. For this system, we used the rabbit as the animal model because the size of their eyes is comparable to that of human. Several pharmacological agents have been used to block the different cells of the retina and to determine the origin of the intrinsic cellular signal in rabbits. The second goal of this project is to develop an optical imaging system of intrinsic signals. This system was designed for the rat animal model. A pharmacological agent (Aspartate) is used to validate this imaging system on rats. Our results indicate that in rabbit bipolar cells are the main cells responsible for the intrinsic retinal signals. Also, approximately 20% of the Ganglion cells also show that 20% play a role in the genesis of intrinsic signals. Our results also indicate that it is possible to construct an efficient imaging system for small animals such as rats. The data obtained with this new retinal imager confirm that the inner retina is at the origin of intrinsic retinal signals

Factors influencing loyalty in hotels' fine dining restaurants moderated by switching cost

v ABSTRACT Many studies have been conducted on developing loyalty model in hospitality and restaurant industry, but the inhibiting factors of restaurant customer switching have yet to be identified. To maintain loyalty the literature has proven that customer satisfaction is connected positively to loyalty in hospitality industry. Hence, the main objective of this thesis is to maintain and to improve loyalty through developing a basic model of service quality-satisfaction-loyalty by taking two steps. First, the service quality model was integrated with the independent variables which were the relationship marketing and the corporate social responsibility. Second, this study examined the moderating role of switching cost on customer satisfaction and loyalty association. Using a survey questionnaire, the data was collected from 120 event organisers of corporations who have the experience of conducting corporate gatherings at hotels’ fine dining restaurants in the Klang Valley area. Partial Least Squares (PLS-SEM) method was used to analyse the reliability and the validity of the measurement model and the hypothesised relationships in the proposed research model. The findings supported the positive relationships between independent variables of the study (i.e. service quality, relationship marketing and corporate social responsibility) and customer satisfaction as a mediator. This research found that the switching cost in hotels’ fine dining consisted of non-monetary cost. The result of this thesis also supported the moderating role of switching cost in satisfaction and loyalty association. The result indicated high switching cost (non-monetary) will decrease the effect of customer satisfaction on loyalty

Computer-aided diagnosis system for bone fracture detection using machine learning algorithms

Diagnostic imaging technology has revolutionized the healthcare industry by allowing more accurate and earlier diagnosis of diseases. This technology reduces the need for invasive procedures such as surgery and enhances the quality of patient care. Several machine learning algorithms like SVM, K-mean clustering and UNET have been demonstrated to be capable of solving classification, detection, and segmentation problems in medical imaging, as well as being used for super-resolution techniques. The purpose of this thesis is to examine machine learning and image processing methods for four key challenges in medical image analysis. The first one is the segmentation of medical images. The second challenge involves implementing super-resolution techniques for medical images. Third, using image processing methods in order to diagnose the abnormalities. The fourth contribution is to enrich the image information by mapping of medical images between different modalities using deep neural models. In this research, all contributions aim at developing an end-to-end model that can detect fractures automatically or be used as a clinical assistant to reduce errors. As the first contribution, the thesis presents a multi-stage novel approach for bone segmentation in X-ray images using faster region-based convolutional neural network (R-CNN) and distance regularized level set evolution (DRLSE) algorithms. A hybrid model utilizing deep neural network (DNN) and image processing techniques are proposed to segment the bones in two stages. Our model is more robust to the changes in X-ray images, as well as applicable to bones that are misplaced. Additionally, we have used transfer learning to reduce the amount of time and effort required to collect and label the data. As the second contribution, DNN models are used to enhance the resolution of medical images. CNN and generative adversarial network have been used as super-resolution techniques to achieve high-resolution medical images. The analysis includes subjective and objective evaluations of different models on regions with or without fractures to compare them with our model. The third contribution involves applying different image analysis methods to X-ray images in order to detect fractures with the minimum amount of human intervention. By using entropy and intensity, we have also attempted to identify regions of interest that have a higher probability of having fractures. We also evaluate the effect of super-resolution technique on the saliency map with and without fractures. Lastly, we present image-to-image mapping by using variational autoencoders and generative adversarial networks to reduce the cost of diagnosis and medical images retrievals. We have attempted to map X-ray images to MRIs in this section in order to fuse the high diagnostic information existing in MRIs, for enhancing the matched X-ray images

A Mysterious Case of ST-Elevation Myocardial Infarction; an Old Man with Weight Loss and Dyspepsia

We present a 65-year-old man who developed retrosternal compressive chest pain. A 12-lead electrocardiography demonstrated ST-segment elevation in leads II, III and aVF. Emergent coronary angiography showed significant thrombus in the distal portion of the left main coronary artery. Abdomino-pelvic computed tomography scan, which was performed the next day, confirmed a pancreatic mass with peritoneal seedings, compatible with peritoneal carcinomatosis. This case underscores the importance of malignancies that may lead to a catastrophic ST-elevation myocardial infarction due to a hypercoagulable state and following thrombosis in the left main coronary artery

Effects of Teaching the management and leadership Skills on Sports Managers’ Knowledge Management and their Organizational Citizenship Behavior

The present study investigates the effects of learning organizational intelligence skills on career self-efficacy, job engagement, and strategic thinking among sports managers. A quasi-experimental research method was adopted for the present study including a pretest, posttest, and follow-up stages using a group control. In this regard, 20 managers and assistants from among managers and deputies of the Faculty of Physical Education and Sport Sciences of Al-Mustansiriya Univesrsity, Iraq were selected as a sample for the purpose of this research, using the convenient method. The sample were randomly assigned into two groups, namely the experimental (10 persons) and control (10 persons) groups respectively. Afterwards, the organizational intelligence training was taught to the managers in the experimental group (8 sessions). The data collected included the 36-item job self-efficacy (Riggs & Knight, 1994), the 10-item job engagement (Kanungo, 1982), and the strategic thinking questionnaires (Jeanne Liedtka, 2008). Data were then analyzed using MANOVA and ANOVA with repeated measures tests. The study results suggest that educating sports managers on organizational intelligence had a significant effect on career self-efficacy, job engagement, and strategic thinking. Furthermore, the effects was still observable in the experimental group three months after the educational intervention

The utility of Helicobacter pylori eradication in improving functional dyspepsia in adult population in Iran

Background: This review aimed at investigating the effectiveness of Helicobacter pylori eradication in improving the symptoms of patients with functional dyspepsia in Iranian adult population. Materials and Methods: This study was a systematic review. Data were collected from the Medline database by searching some keywords including "Helicobacter pylori", "eradication", "effectiveness", "dyspepsia", and "Iran". After obtaining the full text of articles, the critical review was performed based on article titles and abstracts. For each article, information regarding benefits, side effects and efficacy was identified. Then, scenarios were extracted according to the mentioned data. Results: From a total of 28 reviewed papers, 6 were systematic reviews (with the level of evidence 1a), 18 articles were randomized interventional trials (with the level of evidence 1b) and 4 articles were longitudinal studies (with the level of evidence 2b). Most studies reported improvement in symptoms, although some of them did not report the statistically significant difference. After extracting data related to the scenarios from the articles, they were rated regarding the clinical advantage and the ability to localize each scenario. Conclusion: Considering the results of analyzing the articles and extracted scenarios, Helicobacter pylori eradication is recommended in Iranian adult patients with functional dyspepsia, normal upper gastrointestinal endoscopy, and documented Helicobacter pylori infection

The Effect of Hyperuricemia on the Rate of Contrast-Induced Nephropathy in Patients with Coronary Angiography

Introduction: There is little information about the relationship between hyperuricemia and contrast induced nephropathy. The present study aimed to evaluate the relationship between hyperuricemia and contrast induced nephropathy among patients, who had undergone coronary angiography.Methods: In the current study, 200 consecutive patients with coronary artery disease, who underwent coronary angiography in Modarres hospital, were enrolled. According to the available data, the upper limit normal level of uric acid was defined as 7 mg/dl in males and 6.5 mg/dl in females. By increasing level of serum creatinine to 0.5 mg/dl (or 25% enhancement) from basic level of creatinine during 48 hours of introduction of contrast agent, diagnosis of Contrast Induced Nephropathy (CIN) was established. The relationship between hyperuricemia and CIN was then assessed.Results: There is a significant difference between normouricemic patients and hyperuricemic patients, in aspect of weight (P = 0.011) and uric acid (P = 0.001); however, other quantitative and qualitative variables including age, volume of contract agent, creatinine level after angiography, hemoglobin level, gender, arterial access type, number of involved vessels, were insignificant between the two groups (P > 0.05). Moreover, as an essential finding, CIN was shown in 9% of normouricemic patients and 10% of hyperuricemic  patients with no significant difference between the two groups (P = 0.6).Conclusions: Our study suggests that hyperuricemia may not significantly increase the rate of the contrast-induced nephropathy in patients, who had undergone angiograph

An Analysis of the Relationship between Organizational Commitment and Job Performance among Sport Teachers at High Schools in Ahvaz, Iran

The goal of this research is an analysis of the relationship between organizational commitment and job performance among sport teachers at high schools in Ahvaz. In terms of data collection, this study is of descriptive-measurement type. Since the aim of this research is an analysis and illustration of the significance of effects of the independent variable of organizational commitment on the dependent variable of job performance, the correlation method was adopted. The data collection tool was standard questionnaires that were distributed among all sport teachers (190 instructors) in Ahvaz. At the level of inferential statistics, the Pearson Correlation Coefficient was used to analyze the relationship between organizational commitment and its micro-scales with job performance; and the results showed that there is a significant relationship between organizational commitment and job performance among sport teachers  at high schools in Ahvaz  at the level of p<0.01. However, analysis of the three components of organizational commitment separately showed that among the components of affective commitment, continuance commitment and normative commitment, only affective commitment has a significant relationship with job performance. Keywords: organizational commitment, job performance, physical education, sport teacher

The Role of Media, Spectators and Fans in Attracting Sport Sponsors for Developing Sport Clubs

The purpose of present study is to investigate the role of media, spectators, and fans in attracting sport sponsors. The study method is of descriptive-traverse and applied type. The statistical society of the study composed of 925 managers, sport experts and athletes of public and private sport clubs in Esfahan province. The evaluated sample composed of 272 individuals who were selected cluster sampling method in proportion with statistical society. Measuring tool included researcher-made 28-item questionnaire. Justifiability of questionnaire has been studied by professionals' and experts' opinion and the validity of the questionnaire has been obtained through Cronbach's alpha (α=0/86). The study results showed that mass media and spectators and fans were effective in attracting sport fans (p≤0.05)