Browsing by Issue Date, starting with "2016-07-06"
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- Illumination correction and analysis of two-dimensional microscopy images of Loa loa microfilariaePublication . Al-Tam, Faroq; Shahbazkia, Hamid Reza; Anjos, António dosThis thesis addresses the problem of detecting a common parasitic micro laria that causes loaisis, a major disease problem in Central and Western Africa. The dose of medicine to be administered to the patient is proportional to the estimated number of micro lariae in the patient's body. Therefore, proper estimation of the number of micro lariae is the key for conducting the right procedure. The clinical examination is necessary to estimate the micro lariae density in a blood sample drawn from the patient. Thereafter, visual inspection of the sample is performed. The main challenge in this work is, however, the development of an automatic detection system of micro lariae in 2-D images. Such problem is new in the image processing literature, and the development of such system is very important for performing better diagnosis and treatment of this disease and other similar diseases. A comprehensive review of, both generic and thin, object detectors in 2-D images is presented. A very robust method for microscopy image illumination correction is proposed, and a new powerful descriptor, the Hessian-Polar Context (HPC), for micro lariae is also introduced. These are then combined in a micro lariae detection system, where a simple, yet e cient, hypotheses generator is also presented. Additionally, several methods and applications for di erent image modalities are proposed. These involve a method and an application for the analysis of rice panicle in 2-D images. Additionally, an e cient method for artifact suppression in X-ray image is also proposed. The proposed methods are compared to a set of state-of-the-art methods. Experimental results show that the developed methods are great contributions to the microscopy and X-ray imaging elds.
- Characterization of the behavioural phenotype of calpain-knockout micePublication . Silva, Joana Andreia Joaquim da; Araújo, InêsAdult neurogenesis consists of the production of new neurons in specific brain regions, or neurogenic niches. The most relevant niches in rodents are the subventricular zone lining the lateral ventricles and the dentate gyrus of the hippocampus. Neurogenesis has been shown to influence cognitive function dependent on these regions. Evidence from the literature suggests that calpains are able to influence neurogenesis. However, little information is available regarding their participation in neurological functions. We have evaluated the involvement of calpains in cognitive and emotional behaviour by evaluating these functions in mice genetically modified to lack calpain 1, calpain 2, or both calpains. In this work, 12 week old calpain knockout mice for calpain 1, calpain 2, both, or wild type (WT) littermates were used. The mice were tested in the open field, object recognition, Morris water maze, contextual and cued fear conditioning, passive avoidance, elevated plus maze and forced swimming tests, to evaluate neurological function. Results from the elevated plus maze show that calpain2 knockout mice and double knockout mice present an anxious phenotype comparing with WT mice, suggesting that calpain 2, but not calpain 1, is involved in anxiety. Memory, learning, locomotor activity and exploratory behaviour as well as helplessness were similar in calpain knockout and WT mice. Neurogenesis in calpain knockout mice was also similar to WT mice. Overall, our work shows that calpain 2 is involved in anxiety and a clear phenotype was identified in calpain knockout mice regarding their involvement in memory and learning, which is agreement with previously published data using mice that lack the small regulatory subunit of calpains.