Ambiente de realidade virtual para visitas imersivas e interação

Mestrado em Engenharia de Computadores e TelemáticaComo solução para visitas virtuais imersivas a museus, propomos uma extensão à plataforma previamente desenvolvida para efectuar a configuração de ambientes virtuais imersivos (pSIVE), mantendo todas as funcionalidades de criação de ambientes virtuais e de associação de conteúdos (PDF, videos, texto), mas também permitindo interações baseadas em gestos e navegação. Para isso, propomos navegação um para um usando rastreamento do esqueleto com uma Kinect que é calibrada no espaço do mundo real em que o utilizador se situa, assim como métodos de interação por gestos. Para validar os métodos propostos de navegação e interação, foi efetuado um estudo comparativo entre a interação e navegação à base de gestos e em botões. Com os resultados desse estudo em mente, desenvolvemos novos métodos de interação com seleção via direção do olhar. A aplicação desenvolvida foi testada num cenário real, como parte de uma instalação artística no museu da cidade de Aveiro, onde os visitantes podiam navegar uma sala virtual do museu e manipular objetos de maneira a criar a sua própria exposição.Como solução para visitas virtuais imersivas a museus, propomos uma extensão à plataforma previamente desenvolvida para efectuar a configuração de ambientes virtuais imersivos (pSIVE), mantendo todas as funcionalidades de criação de ambientes virtuais e de associação de conteúdos (PDF, videos, texto), mas também permitindo interações baseadas em gestos e navegação. Para isso, propomos navegação um para um usando rastreamento do esqueleto com uma Kinect que é calibrada no espaço do mundo real em que o utilizador se situa, assim como métodos de interação por gestos. Para validar os métodos propostos de navegação e interação, foi efetuado um estudo comparativo entre a interação e navegação à base de gestos e em botões. Com os resultados desse estudo em mente, desenvolvemos novos métodos de interação com seleção via direção do olhar. A aplicação desenvolvida foi testada num cenário real, como parte de uma instalação artística no museu da cidade de Aveiro, onde os visitantes podiam navegar uma sala virtual do museu e manipular objetos de maneira a criar a sua própria exposição

A multicenter validation of an endoscopic classification with narrow band imaging for gastric precancerous and cancerous lesions

BACKGROUND AND STUDY AIM: The reliability and external validity of narrow band imaging (NBI) in the stomach have not been described consistently. The aim of the current study was to describe and estimate the accuracy and reliability of a simplified classification system for NBI in the diagnosis of gastric lesions. METHODS: Consecutive patients undergoing NBI endoscopy at two reference centers (n=85, 33% with dysplasia) were included in two studies. In total, 224 different areas were biopsied and recorded onto video. In the derivation study, previously described NBI features were analyzed in order to develop a simplified classification. In the validation study the accuracy and reliability of this classification were estimated among three groups of endoscopists with different levels of expertise in NBI. .RESULTS: The reliability/accuracy results from the derivation study allowed the creation of a simplified NBI classification. In the validation study, "regular vessels with circular mucosa" (pattern A) was associated with normal histology (accuracy 83%; 95% confidence interval [CI] 75?%-90%); "tubulo-villous mucosa" (pattern B) was associated with intestinal metaplasia (accuracy 84%; 95CI 77%-91%; positive likelihood ratio [LR+]=4.75); and "irregular vessels and mucosa" (pattern C) was associated with dysplasia (accuracy 95%; 95CI 90%-99%; LR+=44.33). The reproducibility of these patterns was high (k=0.62). "Light-blue crest" was moderately reliable (k=0.49) but specific (87%) for intestinal metaplasia. A variable vascular density (additional pattern+) was the best feature for Helicobacter pylori gastritis (accuracy 70%; 95CI 59%-80%) but showed only fair reliability (k=0.38). Non-experienced endoscopists presented lower agreement (k=0.6 vs. k=0.75) and accuracy (74% vs. 86%) than international experts/experienced endoscopists. CONCLUSION: A simplified NBI classification is accurate and reliable for the diagnosis of intestinal metaplasia and dysplasia. The classification should be further assessed and validated on a per-patient assessment of NBI, and by comparing NBI with other imaging technologies.This study was supported by a grant for medical investigation from the Portuguese Digestive Endoscopy Society (SPED 2009 Investigation Grant)

Canine periodontitis : the dog as an important model for periodontal studies

Article in press; Available online 20 September 2011Periodontal disease (PD) refers to a group of inflammatory diseases caused by bacterial plaque in the periodontium and ranges from an early stage (gingivitis) to an advanced stage (periodontitis). It is a multifactorial disease that results from the interaction of the host defence mechanisms with the plaque microorganisms. Early detection, diagnosis and treatment are essential in the control of this disease. PD has an enormous impact on human and veterinary medicine due to its high prevalence. The most common animal PD models use dogs and non-human primates, although other animals (rats, mice, hamsters, rabbits, miniature pigs, ferrets, and sheep) have also been employed. Dog models have contributed significantly to the current understanding of periodontology. The most important clinical aspects of canine PD are considered in this review and the various animal models are examined with an emphasis on the role of the dog as the most useful approach for understanding human PD and in the development of new therapeutic and preventive measures.This work was partially supported by the PhD Grants SFRH/BD/44490/2008 and SFRH/BD/44143/2008 of the Science and Technology Foundation from Portugal

Detection and characterization of interleukin-6 gene variants in canis familiaris: association studies with periodontal disease

Periodontal disease (PD) is the most common inflammatory disease of the oral cavity of domestic carnivores. In Human Medicine molecular genetics research showed that several genes play a role in the predisposition and progression of this complex disease, primarily through the regulation of inflammatory mediators, but the exactly mechanisms are poorly understood. This study aims to contribute to the characterization of the genetic basis of PD in the dog, a classically accepted model in Periodontology. We searched for genetic variations in the interleukin-6 (IL6) gene, in order to verify its association with PD in a case–control study including 25 dogs in the PD case group and 45 dogs in the control group. We indentified and characterized three new genetic variations in IL6 gene. No statistically significant differences were detected between the control and PD cases groups. Our results do not support an evidence for a major role contribution of these variants in the susceptibility to PD in the analyzed population. Nevertheless, the sequence variant I/5_g.105 GNA leads to an amino acid change (arginine to glutamine) and was predicted to be possibly damaging to the IL6 protein. A larger cohort and functional studies would be of extreme importance in a near future to understand the possible role of IL6 variants in this disease

Interleukin-6 gene -174G>C and -636G>C promoter polymorphisms and prostate cancer risk

Prostate cancer (PCa) is one of the most commonly diagnosed internal malignancies affecting men. Due to the important roles of IL-6 in different physiological and pathophysiological processes,IL-6polymorphisms may modulate PCa risk.IL-6−174 G>C (rs 1800795, also designated −236 G>C) and −636 G>C (rs 1800796, also designated −572 G>C) promoter polymorphisms have been implicated in PCa susceptibility, albeit still controversial. A literature search using PubMed and Highwire databases was conducted, resulting in eight case–control studies concerning theIL-6−174 G>C polymorphism (11,613 PCa cases and 13,992 controls) and four case–control publications regarding theIL-6−636 G>C polymorphism (1,941 PCa cases and 3,357 controls). In order to derive a more precise estimation, a meta-analysis based upon these selected case–control studies was performed. There was no significant association betweenIL-6−174 G>C polymorphism and PCa increased risk. Nevertheless, the presence of allele C and the CC genotype were statistically significantly associated with decreased PCa risk in the overall analysis forIL-6−636 G>C polymorphism. Additional studies in larger samples and analyses of functional repercussions of these SNPs in prostate tumor cells are necessary to validate these findings

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved