977 resultados para Rapid Maxilla Expansion


Relevância:

80.00% 80.00%

Publicador:

Resumo:

One of the most enigmatic features of Cenozoic long-term climate evolution is the long-lasting positive carbon-isotope excursion or "Monterey Excursion", which started during a period of global warmth after 16.9 Ma and ended at not, vert, similar 13.5 Ma, approximately 400 kyr after major expansion of the Antarctic ice-sheet. We present high-resolution (1-9 kyr) astronomically-tuned climate proxy records in two complete sedimentary successions from the northwestern and southeastern Pacific (ODP Sites 1146 and 1237), which shed new light on the middle Miocene carbon-isotope excursion and associated climatic transition over the interval 17.1-12.7 Ma. We recognize three distinct climate phases with different imprints of orbital variations into the climatic signals (1146 and 1237 d18O, d13C; 1237 XRF Fe, fraction > 63 µm): (1) climate optimum prior to 14.7 Ma characterized by minimum ice volume and prominent 100 and 400 kyr variability, (2) long-term cooling from 14.7 to 13.9 Ma, principally driven by obliquity and culminating with rapid cryosphere expansion and global cooling at the onset of the last and most pronounced d13C increase, (3) "Icehouse" mode after 13.9 Ma with distinct 100 kyr variability and improved ventilation of the deep Pacific. The "Monterey" carbon-isotope excursion (16.9-13.5 Ma) consists overall of nine 400 kyr cycles, which show high coherence with the long eccentricity period. Superposed on these low-frequency oscillations are high-frequency variations (100 kyr), which closely track the amplitude modulation of the short eccentricity period. In contrast to d13C, the d18O signal additionally shows significant power in the 41 kyr band, and the 1.2 Myr amplitude modulation of the obliquity cycle is clearly imprinted in the 1146 d18O signal. Our results suggest that eccentricity was a prime pacemaker of middle Miocene climate evolution through the modulation of long-term carbon budgets and that obliquity-paced changes in high-latitude seasonality favored the transition into the "Icehouse" climate.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Large blooms of the marine cyanobacterium Lyngbya majuscula in Moreton Bay, Australia (27 degrees 05'S, 153 degrees 08'E) have been re-occurring for several years. A bloom was studied in Deception Bay (Northern Moreton Bay) in detail over the period January-March 2000. In situ data loggers and field sampling characterised various environmental parameters before and during the L. majuscula bloom. Various ecophysiological experiments were conducted on L. majuscula collected in the field and transported to the laboratory, including short-term (2h) C-14 incorporation rates and long-term (7 days) pulse amplitude modulated (PAM) fluorometry assessments of photosynthetic capacity. The effects of L. majuscula on various seagrasses in the bloom region were also assessed with repeated biomass sampling. The bloom commenced in January 2000 following usual December rainfall events, water temperatures in excess of 24 degrees C and high light conditions. This bloom expanded rapidly from 0 to a maximum extent of 8 km(2) over 55 days with an average biomass of 210 g(dw)(-1) m(-2) in late February, followed by a rapid decline in early April. Seagrass biomass, especially Syringodium isoetifolium, was found to decline in areas of dense L. majuscula accumulation. Dissolved and total nutrient concentrations did not differ significantly (P > 0.05) preceding or during the bloom. However, water samples from creeks discharging into the study region indicated elevated concentrations of total iron (2.7-80.6 mu M) and dissolved organic carbon (2.5-24.7 mg L-1), associated with low pH values (3.8-6.7). C-14 incorporation rates by L. majuscula were significantly (P < 0.05) elevated by additions of iron (5 mu M Fe), an organic chelator, ethylenediaminetetra-acetic acid (5 mu M EDTA) and phosphorus (5 mu M PO4-3). Photosynthetic capacity measured with PAM fluorometry was also stimulated by various nutrient additions, but not significantly (P > 0.05). These results suggest that the L. majuscula bloom may have been stimulated by bioavailable iron, perhaps complexed by dissolved organic carbon. The rapid bloom expansion observed may then have been sustained by additional inputs of nutrients (N and P) and iron through sediment efflux, stimulated by redox changes due to decomposing L. majuscula mats. (c) 2004 Elsevier B.V. All rights reserved.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

A Expansão Rápida da Maxila Assistida Cirurgicamente (ERMAC) é um recurso ortodôntico-cirúrgico utilizado no tratamento das más oclusões com deficiência transversal da maxila em pacientes adultos que apresentam a consolidação da sutura palatina mediana. A proposta neste estudo foi a de avaliar as densidades ópticas da sutura palatina mediana antes da ERMAC (fase I), após o fechamento do parafuso expansor (fase II), após 3 meses do fechamento do parafuso expansor (fase III) e após 6 meses do procedimento cirúrgico. A amostra deste estudo foi constituída por 64 radiografias oclusais de 16 pacientes na faixa etária de 18 a 40 anos, sendo 6 do sexo masculino e 10 do sexo feminino que necessitavam submeter-se à Expansão Rápida da Maxila Assistida Cirurgicamente (ERMAC) e com atresia maxilar superior a 5 mm. Foram obtidas as radiografias oclusais e as imagens digitalizadas das quatro fases do estudo. Duas áreas de interesse foram demarcadas nas imagens digitalizadas, uma entre os incisivos centrais superiores e outra após o término do parafuso expansor. Procedeu-se às leituras das densidades ópticas pelo programa Image Tool for Windows por meio do Histograma. Após a análise estatística dos valores obtidos de densidade óptica das regiões analisadas pela Análise de Variâncias (ANOVA) e comparações múltiplas de Bonferroni (complemento da ANOVA), pode-se concluir que: a densidade óptica na região da sutura palatina mediana nas 4 fases estudadas, apresentou grande variação, compatível com a abertura da referida sutura e posterior neoformação óssea no período pós-operatório; foi observado valor decrescente para as densidades ópticas após o fechamento do parafuso expansor nas regiões A e B ; foi observado que após 3 meses do fechamento do parafuso expansor, as densidades ópticas aumentaram nas regiões A e B . Isso sugeriu neoformação óssea na região da sutura palatina mediana; foi observado que após 6 meses do procedimento cirúrgico, as densidades ópticas aumentaram em relação à fase anterior. Na região A , observou-se que os valores das densidades ópticas não retornaram aos valores pré-tratamento, ou seja, antes da Expansão Rápida da Maxila Assistida Cirurgicamente (ERMAC). Já os valores das densidades ópticas médias da região B retornaram aos valores iniciais, antes da ERMAC. A análise estatística revelou que após 6 meses do procedimento cirúrgico, houve diferença estatisticamente significante ao se avaliar a região A comparando as fases entre si, porém ao se avaliar a região B não houve diferença estatisticamente significante ao se comparar as fases I e IV.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

A expansão rápida da maxila assistida cirurgicamente (ERMAC) é um dos procedimentos de escolha para correção da deficiência transversal em pacientes adultos. Este estudo avaliou as alterações produzidas nos arcos dentais superiores e inferiores de 18 pacientes, sendo seis do sexo masculino e 12 do sexo feminino, com média de idade de 23,3 anos submetidos à ERMAC. Para cada paciente foram preparados três modelos de gesso, que foram digitalizados por meio do Scanner 3D, obtidos em diferentes fases: inicial, antes do procedimento operatório (T1); três meses pós-expansão (T2); seis meses pós-expansão (T3). Foram avaliadas as distâncias transversais do arcos dentários superior e inferior, a inclinação dentária dos dentes posteriores superiores, a altura da coroa clínica dos dentes posteriores do arco superior e foi observado se havia correlação entre a quantidade de inclinação dentária com o desenvolvimento de recessões gengivais. Para análise dos resultados foram utilizados a análise de Variância, o Teste de Tukey e o Teste de Correlação de Pearson, sendo que para a análise do erro sistemático intra-examinador foi utilizado o teste t pareado e para determinação do erro casual utilizou-se o cálculo do erro de Dahlberg. Com base na metodologia utilizada e nos resultados obtidos, pode-se concluir que: 1. com relação as alterações produzidas no sentido transversal do arco superior, obteve-se um aumento em todas as variáveis de T1 para T2 e uma manutenção dos valores em todas as variáveis de T2 para T3 demonstrando efetividade e estabilidade do procedimento; 2. no arco inferior não houve alterações transversais estatisticamente significantes, com exceção dos primeiros molares; 3. com relação às inclinações dentárias, observou-se um aumento desta de T1 para T2 em todos os dentes, porém, com significância estatística apenas para segundo molar e primeiro e segundo pré-molar do lado direito e primeiro molar e segundo pré-molar do lado esquerdo.; 4. a ERMAC não acarretou o desenvolvimento de recessões gengivais em nenhum dos tempos; 5. não houve correlação entre a quantidade de inclinação dentária e o desenvolvimento de recessões gengivais.(AU)

Relevância:

80.00% 80.00%

Publicador:

Resumo:

O objetivo desta pesquisa foi avaliar as alterações faciais decorrentes da Expansão Rápida da Maxila Assistida Cirurgicamente (ERM-AC). A amostra foi composta por 15 pacientes com idade média de 24 anos e 1 mês, sendo 10 do sexo feminino e 5 do sexo masculino, que apresentavam deficiência transversal da maxila, não tinham sido submetidos a tratamento ortodôntico prévio, apresentavam ficha clínica completa e fotografias em norma frontal nas fases pré-tratamento (T1) e 6 meses após a ERM-AC (T2). Mediadas lineares foram obtidas a partir da marcação de pontos de referência em folhas de acetato fixadas sobre as fotografias, para evitar a necessidade de execução de desenho anatômico. Concluiu-se que a padronização de fotografias em todos os tempos da pesquisa é de fundamental importância para que as medidas avaliadas sejam confiáveis. Quando comparados T1 com T2 por meio do teste t de Student não se verificou alteração estatisticamente significante na: largura intercantal (Ind Ine), altura facial média (N - SN), largura do olho direito (Exd Ind), largura do olho esquerdo (Exe Ine), altura facial (N - Me ), largura facial superior (Zid - Zie ), largura da boca (Cbd Cbe) e altura da boca (Ls Li). As medidas altura facial inferior (Sn - Me ) e a largura do nariz (Ald Ale) apresentaram alteração estatisticamente significante após a ERM-AC.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

A proposta do presente estudo foi avaliar os efeitos do laser de baixa intensidade na regeneração óssea no procedimento de expansão rápida da maxila. Utilizou-se 27 indivíduos com média de idade de 10,2 anos, divididos em dois grupos: grupo laser (n=14), no qual se realizou a expansão rápida da maxila, associada ao laser e grupo sem laser (n=13), que realizou somente a expansão rápida da maxila. O protocolo de ativação do parafuso expansor foi de 1 volta completa no primeiro dia e ½ volta diária até a sobrecorreção. O laser utilizado foi o de diodo (TWIN Laser MMOptics®, São Carlos), seguindo o protocolo de aplicação: comprimento de onda de 780nm, potência de 40mW, densidade de 10J/cm2, em 10 pontos localizados ao redor da sutura palatina mediana. Os estágios de aplicação foram: L1 (do primeiro ao quinto dia de aplicação), L2 (travamento do parafuso e 3 dias seguidos), L3, L4 e L5 (após 7, 14 e 21 dias do L2, respectivamente). Radiografias oclusais da maxila foram realizadas com auxílio de uma escala de alumínio, para referencial densitométrico, em diferentes tempos: T1 (inicial), T2 (dia de travamento do parafuso), T3 (3 a 5 dias do T2), T4 (30 dias do T3), T5 (60 dias do T4). As radiografias foram digitalizadas e submetidas a um programa de imagem (Image Tool - UTHSCSA, Texas, USA), para mensuração da densidade óptica das áreas previamente selecionadas. Para realização do teste estatístico, utilizou-se a Análise de Covariância usando como covariável o tempo para a fase avaliada. Em todos os testes foi adotado nível de significância de 5% (p<0,05).Para o Grupo Laser, os dados mostram que houve uma queda significante de densidade durante a abertura do parafuso (T2-T1), um aumento significante da mesma no período final de avaliação (T5-T4), e um aumento também da densidade no período de regeneração propriamente dito (T5-T2), ou seja, a partir do momento em que finalizou a fase de abertura do parafuso expansor. Enquanto que no Grupo Sem Laser, a densidade não mostrou diferença estatisticamente significantemente em nenhum período analisado. Os resultados mostraram que o laser propiciou consideravelmente uma melhor abertura da sutura palatina mediana, além de influenciar no processo de regeneração óssea da sutura, acelerando seus processos de reparo.(AU)

Relevância:

80.00% 80.00%

Publicador:

Resumo:

O objetivo deste estudo foi avaliar as possíveis alterações das características horizontais, verticais, de simetria e do arco do sorriso de pacientes com atresia maxilar submetidos à expansão rápida da maxila. A amostra consistiu de 81 fotografias extra-bucais do sorriso máximo de 27 pacientes com idade média de 10 anos e 3 meses. Foram realizadas fotografias do sorriso máximo nos períodos: inicial (antes da instalação do aparelho expansor); 3 meses após a fixação do parafuso expansor; 6 meses após a fixação do parafuso expansor. Para a calibragem e análise das fotografias foi utilizado o programa CEFX 2001 CDT. Os pontos fotométricos e as medidas a serem analisadas foram escolhidos após revisão da literatura do sorriso realizada. Para avaliar as alterações no sorriso durante as fases, foi utilizada a análise de variância ANOVA, com nível de significância de 5%. A expansão rápida da maxila promoveu aumento estatisticamente significante da dimensão transversal do sorriso; aumento da quantidade de exposição dos incisivos centrais e laterais superiores; manutenção da simetria entre os lados direito e esquerdo e da falta de paralelismo entre a curvatura das bordas dos incisivos superiores com a curvatura do lábio inferior (arco do sorriso).(AU)

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Small fishes in seasonally flooded environments such as the Everglades are capable of spreading into newly flooded areas and building up substantial biomass. Passive drift cannot account for the rapidity of observed population expansions. To test the ‘reaction–diffusion’ mechanism for spread of the fish, we estimated their diffusion coefficient and applied a reaction–diffusion model. This mechanism was also too weak to account for the spatial dynamics. Two other hypotheses were tested through modeling. The first—the ‘refuge mechanism’—hypothesizes that small remnant populations of small fishes survive the dry season in small permanent bodies of water (refugia), sites where the water level is otherwise below the surface. The second mechanism, which we call the ‘dynamic ideal free distribution mechanism’ is that consumption by the fish creates a prey density gradient and that fish taxis along this gradient can lead to rapid population expansion in space. We examined the two alternatives and concluded that although refugia may play an important role in recolonization by the fish population during reflooding, only the second, taxis in the direction of the flooding front, seems capable of matching empirical observations. This study has important implications for management of wetlands, as fish biomass is an essential support of higher trophic levels.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Residential homegardens have environmental and social roles in the urban environment. These green spaces can potentially minimize the impacts caused by the growth of cities, being an alternative to connect fragmented areas or offer refuge to wildlife and therefore support the conservation of biodiversity. In addition, the homegardens demonstrate a leading role in increasing human well-being by promoting socialization opportunities, contact with nature, local culture as well as improvements in food security for the urban families. Nevertheless, it is still unclear what specific characteristics of homegardens can act effectively in the conservation of the biodiversity, as well as in the construction of food security and well being of the homegardeners and their families. The first chapter of this thesis analyzed the diversity of plant species (native and exotic) and assessed the contribution of different types of urban gardens (ornamental and forest gardens alike) in the presence of wildlife such as birds, monkeys and lizards. In the second chapter we evaluated the contribution of those gardens to the welfare and food security of their owners. In order to do this, 41 gardens were visited in Pium, a southern coastal town in the northeastern Brazil, which also happens to be in a periurban region undergoing rapid urban expansion and pressure from the real estate market. We surveyed the planned biodiversity and fauna associated with homegardens. The data related to food security and welfare were sampled through interviews with the person in charge of taking care of the gardens. These interviews covered issues on the supply of food from the garden and absence of chemical products, as well as aspects of the GNH indicator (Gross National Happiness). The results showed that these homegardens generally contribute little to the maintenance of native plant species (native species = 29/ total = 187). From its main features, the gardens were classified as ornamental, forest gardens and forest farms. These groups had a different effect on the presence of the animals studied and the last two contained most of the sampled native species. The diversity of plants and trees was a good predictor of the presence of birds and monkeys. Thus, the contribution of yards for the conservation of biodiversity depends on the type of garden: some even can have negative effects on conservation. These results can direct new approaches to detailed understanding of gardens and also of public policies applied to urban planning. The results of the second chapter showed that the two types of forest gardens contributed to household food security, for providing food and medicinal herbs, which mostly did not have pesticides and chemical 12 fertilizers. But the three groups of gardens are important components for the well being of their stakeholders. Gardens help promote the transmission of knowledge on agriculture, socialization, contact with nature and bring up feelings related to peace and harmony. Thus, forest gardens can be considered important means to get through public projects and policies designed to encourage biodiversity and promote food security and well-being in urban areas

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Two distinct phosphoenolpyruvate carboxylase (PEPC) isozymes occur in vascular plants and green algae: plant-type PEPC (PTPC) and bacterial-type PEPC (BTPC). PTPC polypeptides typically form a tightly regulated cytosolic Class-1 PEPC homotetramer. BTPCs, however, appear to be less widely expressed and to exist only as catalytic and regulatory subunits that physically interact with co-expressed PTPC subunits to form hetero-octameric Class-2 PEPC complexes that are highly desensitized to Class-1 PEPC allosteric effectors. Yeast two-hybrid studies indicated that castor plant BTPC (RcPPC4) interacts with all three Arabidopsis thaliana PTPC isozymes, and that it forms stronger interactions with AtPPC2 and AtPPC3, suggesting that specific PTPCs are preferred for Class-2 PEPC formation. In contrast, Arabidopsis BTPC (AtPPC4) appeared to interact very weakly with AtPPC2 and AtPPC3, suggesting that BTPCs from different species may have different physical properties, hypothesized to be due to sequence dissimilarities within their ~10 kDa intrinsically disordered region. Recent RNA-seq and microarray data were analyzed to obtain a better understanding of BTPC expression patterns in different tissues of various monocot and dicot species. High levels of BTPC transcripts, polypeptides and Class-2 PEPC complexes were originally discovered in developing castor seeds, but the analysis revealed a broad range of diverse tissues where abundant BTPC transcripts are also expressed, such as the developing fruits of cucumber, grape, and tomato. Marked BTPC expression correlated well with the presence of ~116 kDa immunoreactive BTPC polypeptides, as well as Class-2 PEPC complexes in the immature fruit of cucumbers and tomatoes. It is therefore hypothesized that in vascular plants BTPC and thus Class-2 PEPC complexes maintain anaplerotic PEP flux in tissues with elevated malate levels that would potently inhibit ‘housekeeping’ Class-1 PEPCs. Elevated levels of malate can be used by biosynthetically active sink tissues such as immature tomatoes and cucumbers for rapid cell expansion, drought or salt stressed roots for osmoregulation, and developing seeds and pollen as a precursor for storage lipid and protein biosynthesis.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Thesis (Master, Biology) -- Queen's University, 2016-09-29 20:09:46.997

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Bridge deck expansion joints are used to allow for movement of the bridge deck due to thermal expansion, dynamics loading, and other factors. More recently, expansion joints have also been utilized to prevent the passage of winter de-icing chemicals and other corrosives applied to bridge decks from penetrating and damaging substructure components of the bridge. Expansion joints are often one of the first components of a bridge deck to fail and repairing or replacing expansion joints are essential to extending the life of any bridge. In the Phase I study, the research team focused on the current means and methods of repairing and replacing bridge deck expansion joints. Research team members visited with Iowa Department of Transportation (DOT) Bridge Crew Leaders to document methods of maintaining and repairing bridge deck expansion joints. Active joint replacement projects around Iowa were observed to document the means of replacing expansion joints that were beyond repair, as well as, to identify bottlenecks in the construction process that could be modified to decrease the length of expansion joint replacement projects. After maintenance and replacement strategies had been identified, a workshop was held at the Iowa State Institute for Transportation to develop ideas to better maintain and replace expansion joints. Maintenance strategies were included in the discussion as a way to extend the useful life of a joint, thus decreasing the number of joints replaced in a year and reducing the traffic disruptions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Since 2000, the southwestern Brazilian Amazon has undergone a rapid transformation from natural vegetation and pastures to row-crop agricultural with the potential to affect regional biogeochemistry. The goals of this research are to assess wavelet algorithms applied to MODIS time series to determine expansion of row-crops and intensification of the number of crops grown. MODIS provides data from February 2000 to present, a period of agricultural expansion and intensification in the southwestern Brazilian Amazon. We have selected a study area near Comodoro, Mato Grosso because of the rapid growth of row-crop agriculture and availability of ground truth data of agricultural land-use history. We used a 90% power wavelet transform to create a wavelet-smoothed time series for five years of MODIS EVI data. From this wavelet-smoothed time series we determine characteristic phenology of single and double crops. We estimate that over 3200 km(2) were converted from native vegetation and pasture to row-crop agriculture from 2000 to 2005 in our study area encompassing 40,000 km(2). We observe an increase of 2000 km(2) of agricultural intensification, where areas of single crops were converted to double crops during the study period. (C) 2007 Elsevier Inc. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Rapid alkalinization factor (RALF) is part of a growing family of small peptides with hormone characteristics in plants. Initially isolated from leaves of tobacco plants, RALF peptides can be found throughout the plant kingdom and they are expressed ubiquitously in plants. We took advantage of the small gene family size of RALF genes in sugarcane and the ordered cellular growth of the grass sugarcane leaves to gain information about the function of RALF peptides in plants. Here we report the isolation of two RALF peptides from leaves of sugarcane plants using the alkalinization assay. SacRALF1 was the most abundant and, when added to culture media, inhibited growth of microcalli derived from cell suspension cultures at concentrations as low as 0.1 mu M. Microcalli exposed to exogenous SacRALF1 for 5 days showed a reduced number of elongated cells. Only four copies of SacRALF genes were found in sugarcane plants. All four SacRALF genes are highly expressed in young and expanding leaves and show a low or undetectable level of expression in expanded leaves. In half-emerged leaf blades, SacRALF transcripts were found at high levels at the basal portion of the leaf and at low levels at the apical portion. Gene expression analyzes localize SacRALF genes in elongation zones of roots and leaves. Mature leaves, which are devoid of expanding cells, do not show considerable expression of SacRALF genes. Our findings are consistent with SacRALF genes playing a role in plant development potentially regulating tissue expansion.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background: Although there is evidence demonstrating an association between chronic obstructive pulmonary disease (COPD) and abdominal aortic aneurysm (AAA), it is not clear whether COPD predicts greater rates of expansion of established aneurysms. We sought such an association in a cohort of men with aneurysms detected in a population-based study of screening for aneurysms. Methods: In addition to regular aortic ultrasound scans, 179 men with AAA underwent full lung function testing in order to identify the presence of COPD and its subgroups, emphysema and other obstructive ventilatory defects (OVD). The rate of expansion of each aneurysm was calculated and the men were divided into 'rapid expanders' (3 mm or more per year) and 'slow expanders' (less than 3 mm per year). Any association with the presence of COPD or smoking was tested using a multivariate model. Results: Over a median follow-up period of 36 months the mean rate of aortic expansion for the cohort of 179 men was 2.1 mm/year. There was no significant difference in prevalence of COPD (68% overall) or having ever been a smoker (87% overall) between the rapid expanders and the slow expanders. Conclusions: Although there was a high prevalence of COPD among men with an AAA, there was no association between the rate of expansion of AAA and the presence of any form of this disease.