Prevalência e distribuição de anomalias dentárias e ósseas numa população pediátrica da FMDUL: estudo radiográfico

Tese de Mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2013O presente trabalho de investigação teve como objectivos estabelecer a prevalência de anomalias dentárias e dos maxilares de uma população pediátrica da Faculdade de Medicina Dentária da Universidade de Lisboa (FMDUL), avaliando a sua distribuição por sexo e localização. Para o efeito, observaram-se ortopantomografias de pacientes atendidos nas Clínica Odontopediátrica I e II da FMDUL entre 2011 e 2013, de idades superiores a 4 anos, com recurso ao programa informático OsiriX® e recolheram-se dados como idade, sexo, tipo e localização da patologia. Foram pesquisadas alterações dentárias de número, tamanho, forma, composição e erupção, transposições, reabsorções radiculares, restos radiculares, lesões periapicais ou de furca, osteítes periapicais, quistos e tumores dos maxilares. Após a aplicação dos critérios de exclusão, obtiveram-se 63 radiografias nas quais se diagnosticaram 103 lesões em 65,3% dos pacientes incluídos, a maioria em dentes permanentes com maior prevalência de patologias na arcada maxilar e regiões posteriores. As alterações mais frequentemente observadas foram as de taurodontismo (19%), lesões periapicais (19%) e agenesias dentárias (17,5%), com distribuição semelhante entre ambos os sexos. Registaram-se outras anomalias com menor prevalência tais como dentes impactados (9,5%), dentes supranumerários (4,8%), restos radiculares (4,8%), lesões de furca (4,8%), cúspide em garra (3,2%), posição ectópica (3,2%), microdontia (3,2%), atraso generalizado de erupção (1,6%) e anquilose (1,6%) Os valores de prevalência obtidos diferem dos de outros estudos epidemiológicos muito provavelmente devido a diferenças nos critérios de inclusão, tamanhos das amostras, distribuição de géneros e idades, raças, métodos de observação, técnicas radiográficas utilizadas e parâmetros de diagnóstico.This study intends to estimate the prevalence of dental and jaw anomalies of paediatric population from the Faculty of Dental Medicine of the University of Lisbon (FDMUL), and evaluate its distribution by gender and location. To this end, panoramic radiographs of patients who had visited the Paediatric Dental Clinic I and II of FDMUL between 2011 and 2013, over four years of age, were reviewed using the computer software OsiriX®, and the following data was collected: date of birth, sex, medical history, date of radiography, type of anomaly and location. Dental changes of number, size, shape, composition and eruption, transpositions, root resorption, root fragments, periapical and furcation lesions, periapical osteitis, cysts and tumors of the jaws. After applying the exclusion criteria, 63 radiographs were obtained. 65.3% of these presented a total of 103 lesions, mainly of permanent teeth and located on the maxilla and posterior teeth and jaws. The most frequently observed conditions were taurodontism (19%), periapical lesions (19%) and hypodontia (17.5%), with similar distribution between both genders. Other anomalies showed lower prevalence such as impacted teeth (9.5%), supernumerary teeth (4.8%), root fragments (4.8%), furcation lesions (4.8%), Talon’s cusp (3.2%), ectopic position (3.2%), microdontia (3.2%), delayed generalized rash (1.6%) and tooth ankylosis (1.6%) The prevalence of dental and jaw anomalies differ from those of other epidemiological studies most likely due to differences in inclusion criteria, sample sizes, distribution of genders, ages, races, observation methods, radiographic examination used and diagnostic parameters

Metabolic profiling of diabetic cats in remission

Background: The majority of diabetic cats in remission have abnormal glucose tolerance, and approximately one third relapse within 1 year. Greater understanding of the metabolic characteristics of diabetic cats in remission, and predictors of relapse is required to effectively monitor and manage these cats. Objectives: To identify and compare differences in plasma metabolites between diabetic cats in remission and healthy control cats using a metabolomics approach. Secondly, to assess whether identified metabolites are predictors of diabetic relapse. Animals: Twenty cats in diabetic remission for a median of 101 days, and 22 healthy matched control cats. Methods: Cats were admitted to a clinic, and casual blood glucose was recorded. After a 24 h fast, blood glucose concentration was measured, then a blood sample was taken for metabolomic (GCMS and LCMS) analyses. Three hours later, a simplified intravenous glucose tolerance test (1 g glucose/kg) was performed. Cats were monitored for diabetes relapse for at least 9 months (270 days) after baseline testing. Results: Most cats in remission continued to display impaired glucose tolerance. Concentrations of 16 identified metabolites differed (P ≤ 0.05) between remission and control cats: 10 amino acids and stearic acid (all lower in remission cats), and glucose, glycine, xylitol, urea and carnitine (all higher in remission cats). Moderately close correlations were found between these 16 metabolites and variables assessing glycaemic responses (most |r| = 0.31 to 0.69). Five cats in remission relapsed during the study period. No metabolite was identified as a predictor of relapse. Conclusion and clinical importance: This study shows that cats in diabetic remission have abnormal metabolism

Measures of insulin sensitivity, leptin, and adiponectin concentrations in cats in diabetic remission compared to healthy control cats

Objectives: Firstly, to compare differences in insulin, adiponectin, leptin, and measures of insulin sensitivity between diabetic cats in remission and healthy control cats, and determine whether these are predictors of diabetic relapse. Secondly, to determine if these hormones are associated with serum metabolites known to differ between groups. Thirdly, if any of the hormonal or identified metabolites are associated with measures of insulin sensitivity. Animals: Twenty cats in diabetic remission for a median of 101 days, and 21 healthy matched control cats. Methods: A casual blood glucose measured on admission to the clinic. Following a 24 h fast, a fasted blood glucose was measured, and blood sample taken for hormone (i.e., insulin, leptin, and adiponectin) and untargeted metabolomic (GC-MS and LC-MS) analysis. A simplified IVGGT (1 g glucose/kg) was performed 3 h later. Cats were monitored for diabetes relapse for at least 9 months (270 days). Results: Cats in diabetic remission had significantly higher serum glucose and insulin concentrations, and decreased insulin sensitivity as indicated by an increase in HOMA and decrease in QUICKI and Bennett indices. Leptin was significantly increased, but there was no difference in adiponectin (or body condition score). Several significant correlations were found between insulin sensitivity indices, leptin, and serum metabolites identified as significantly different between remission and control cats. No metabolites were significantly correlated with adiponectin. No predictors of relapse were identified in this study. Conclusion and clinical importance: Insulin resistance, an underlying factor in diabetic cats, persists in diabetic remission. Cats in remission should be managed to avoid further exacerbating insulin resistance

Metabolic profiling of a transgenic Caenorhabditis elegans Alzheimer model

Despite decades of research, no early-onset biomarkers are currently available for Alzheimer’s disease, a cureless neurodegenerative disease afflicting millions worldwide. In this study, transgenic Caenorhabditis elegans were used to investigate changes in the metabolome after induced expression of amyloid-β. GC- and LC–MS-based platforms determined a total of 157 differential features. Some of these were identified using in-house (GC–MS) or public libraries (LC–MS), revealing changes in allantoin, cystathionine and tyrosine levels. Since C. elegans is far better suited to metabolomics studies than most other model systems, the accordance of these findings with vertebrate literature is promising and argues for further use of C. elegans as a model of human pathology in the study of AD

Magnetic relaxation phenomena and cluster glass properties of La{0.7-x}Y{x}Ca{0.3}MnO{3} manganites

The dynamic magnetic properties of the distorted perovskite system La{0.7-x}Y{x}Ca{0.3}MnO{3} (0 <= x <= 0.15) have been investigated by ac-susceptibility and dc magnetization measurements, with emphasis on relaxation and aging studies. They evidence for x >= 0.10 the appearance of a metallic cluster glass phase, that develops just below the ferromagnetic transition temperature. The clusters grow with decreasing temperature down to a temperature T(f0) at which they freeze due to severe intercluster frustration. The formation of these clusters is explained by the presence of yttrium induced local structural distortions that create localized spin disorder in a magnetic lattice where double-exchange ferromagnetism is dominant.Comment: Accepted for publication in Phys. Rev.

Local non-Gaussianity from rapidly varying sound speeds

We study the effect of non-trivial sound speeds on local-type non-Gaussianity during multiple-field inflation. To this end, we consider a model of multiple-field DBI and use the deltaN formalism to track the super-horizon evolution of perturbations. By adopting a sum separable Hubble parameter we derive analytic expressions for the relevant quantities in the two-field case, valid beyond slow variation. We find that non-trivial sound speeds can, in principle, curve the trajectory in such a way that significant local-type non-Gaussianity is produced. Deviations from slow variation, such as rapidly varying sound speeds, enhance this effect. To illustrate our results we consider two-field inflation in the tip regions of two warped throats and find large local-type non-Gaussianity produced towards the end of the inflationary process.Comment: 30 pages, 7 figures; typos corrected, references added, accepted for publication in JCA

A Statistical Approach to Multifield Inflation: Many-field Perturbations Beyond Slow Roll

We study multifield contributions to the scalar power spectrum in an ensemble of six-field inflationary models obtained in string theory. We identify examples in which inflation occurs by chance, near an approximate inflection point, and we compute the primordial perturbations numerically, both exactly and using an array of truncated models. The scalar mass spectrum and the number of fluctuating fields are accurately described by a simple random matrix model. During the approach to the inflection point, bending trajectories and violations of slow roll are commonplace, and 'many-field' effects, in which three or more fields influence the perturbations, are often important. However, in a large fraction of models consistent with constraints on the tilt the signatures of multifield evolution occur on unobservably large scales. Our scenario is a concrete microphysical realization of quasi-single-field inflation, with scalar masses of order $H$, but the cubic and quartic couplings are typically too small to produce detectable non-Gaussianity. We argue that our results are characteristic of a broader class of models arising from multifield potentials that are natural in the Wilsonian sense.Comment: 39 pages, 17 figures. References added. Matches version published in JCA

Accidental Inflation in the Landscape

We study some aspects of fine tuning in inflationary scenarios within string theory flux compactifications and, in particular, in models of accidental inflation. We investigate the possibility that the apparent fine-tuning of the low energy parameters of the theory needed to have inflation can be generically obtained by scanning the values of the fluxes over the landscape. Furthermore, we find that the existence of a landscape of eternal inflation in this model provides us with a natural theory of initial conditions for the inflationary period in our vacuum. We demonstrate how these two effects work in a small corner of the landscape associated with the complex structure of the Calabi-Yau manifold P^4_[1,1,1,6,9] by numerically investigating the flux vacua of a reduced moduli space. This allows us to obtain the distribution of observable parameters for inflation in this mini-landscape directly from the fluxes.Comment: 40 pages, 11 figure

An embedded cohesive crack model for finite element analysis of quasi-brittle materials

This paper presents a numerical implementation of the cohesive crack model for the anal-ysis of quasibrittle materials based on the strong discontinuity approach in the framework of the finite element method. A simple central force model is used for the stress versus crack opening curve. The additional degrees of freedom defining the crack opening are determined at the crack level, thus avoiding the need for performing a static condensation at the element level. The need for a tracking algorithm is avoided by using a consistent pro-cedure for the selection of the separated nodes. Such a model is then implemented into a commercial program by means of a user subroutine, consequently being contrasted with the experimental results. The model takes into account the anisotropy of the material. Numerical simulations of well-known experiments are presented to show the ability of the proposed model to simulate the fracture of quasibrittle materials such as mortar, concrete and masonry