Indiana University-Purdue University Indianapolis (IUPUI) / This investigation compared the spring characteristics of three space closing assemblies; the classic "Bull" loop and two new spring designs currently being used in the Department of Orthodontics at Indiana University. Using interbracket distance and the degree of gable preactivation as variables, a complete laboratory analysis was carried out on each spring design. A total of two hundred springs were tested. A statistical investigation was conducted to determine if the spring designs had significantly different load-deflection rates, moment to force ratios, and range of activation. The range of activation for all three spring designs was large enough to be of some minor importance in determining the difference in efficiency of each design. However, when the load-deflection rates and moment to force ratios of the "Bull" loop and the two new spring designs were compared, the new spring designs invariably proved to be superior. From this laboratory study, it was concluded that the two new spring designs have the potential of providing a more efficient method of orthodontic space closure.

Thesis. / Includes reprints of 4 supporting articles. Includes bibliographical references (p. 23-26).

Thesis. / Includes reprints of 4 supporting articles. Includes bibliographical references (p. 23-26).

Black carbon (BC), a stable form of organic carbon (OC), is a byproduct of the incomplete combustion of biomass, biofuels, and fossil fuel. The main objectives of this research are to examine the spatial distribution of OC and BC in urban soil and determine the influence of tree canopy cover and landscape maintenance on soil carbon accumulation. Soil sampling was conducted at 29 sites throughout the City of Denton, Texas, in May 2019. Samples were collected from underneath post oak canopies and in adjacent open areas and were analyzed for total carbon (TC), total organic carbon (TOC), total N (TN), C:N ratio, and BC. Although maintenance levels had no significant effect, TOC was greater underneath trees (5.47%, 5.30 kg/m2) than lawns (3.58%, 4.84 kg/m2) at the surface 0-10 cm. Total nitrogen concentration was also greater underneath trees (0.43%) than lawns (0.31%) at the surface 0-10 cm. Preliminary results for BC were closely correlated to TOC. The lack of difference in C:N ratio between cover types indicates that leaf litter quality may not be the primary driving factor in soil C and N accumulation. Instead, differences in soil properties may be best explained by manual C inputs and greater atmospheric deposition of C and N to soils with tree canopy cover. Identifying patterns and potential drivers of soil OC and BC accumulation is important because soil carbon sequestration not only reduces atmospheric CO2, but also may provide additional pollution mitigation benefits, thereby contributing to a more sustainable urban environment.

Orientador: Maria Beatriz Duarte Gavião / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-14T09:01:42Z (GMT). No. of bitstreams: 1 Serra-Vicentin_MarciaDiaz_D.pdf: 3082308 bytes, checksum: 2f06d20acd5f2c440c3df736ad19d3b8 (MD5) Previous issue date: 2009 / Resumo: Diversos são os fatores que parecem interferir na mastigação: força de mordida (que pode estar relacionada ao tamanho dos músculos), componentes e quantidade de saliva, características da oclusão, dentre outros. Esta tese está composta de cinco capítulos. O capítulo 1 "The use of ultrasound in the investigation of the muscles of mastication" revisou a literatura a respeito das imagens ultrasonográficas (US) dos músculos da mastigação e reforçou que a US é um método confiável de grande utilidade no campo do diagnóstico de alterações dos músculos da mastigação e do estudo de mudanças durante o crescimento e envelhecimento e que permanece como uma técnica promissora para o estudo dos músculos da mastigação. O capítulo 2, "Correlation between muscle thickness and bite force in children before and after oral rehabilitation - a 2 year logitudinal study", avaliou a correlação entre força de mordida (FM) e espessura muscular antes e após 6, 12 e 24 meses de reabilitação bucal (T0, T6, T12, T24, respectivamente) em 19 crianças de 6-9 anos que apresentavam perda precoce de dentes decíduos. A FM foi determinada com um transdutor pressurizado flexível. A espessura dos músculos masseter e temporal foi mensurada durante relaxamento e máxima intercuspidação com US digital com transdutor linear de 56mm/10-MHz. Houve aumento significativo da FM e espessura do masseter entre T0 e T12. A FM e a espessura do temporal relaxado e contraído em T6 e temporal contraído em T24 foram significativamente correlacionadas. Foi concluído que houve aumento da FM e espessura do masseter após a reabilitação e também relação entre FM e espessura do temporal, o que sugere que a reabilitação bucal influenciou os aspectos morfológicos e funcionais dos músculos da mastigação. Os capítulos 3 "Bite force and salivary flow rate in schoolchildren", 4 "Bite force, texture perception and chewing parameters in schoolchildren" e 5 "Salivary flow rate, protein content, chewing parameters, and taste perception in schoolchildren" tiveram como objetivos avaliar e correlacionar o fluxo salivar (FS), FM, parâmetros de mastigação, percepção de sabor e textura de alimentos e o papel da proteína na mastigação em crianças de 7-10 anos de idade distribuídas de acordo com fase da dentição, oclusão e sexo. A saliva total não estimulada (NE) e estimulada (E) por parafilm foram coletadas por 5 minutos para obtenção do FS. A proteína total foi avaliada pelo método de Lowry et al. (1951). A FM foi determinada como um transdutor pressurizado flexível. Os seguintes alimentos foram testados: cenoura, torrada com e sem margarina, banana, queijo e goma de mascar para determinar os parâmetros mastigatórios (tempo de mastigação, número e freqüência de ciclos mastigatórios), a textura (utilizando uma escala visual analógica de 0 a 100 mm) e o sabor (classificado como amargo, azedo, salgado ou doce). Meninos apresentaram FS e FM (Capítulo 3) significativamente maior que as meninas. Houve correlação significativa entre FS e FM para o grupo com oclusão normal. Não houve diferença significativa na FM, textura ou nos parâmetros da mastigação entre os grupos de oclusão. Os parâmetros da mastigação e a textura foram significativamente menores para os alimentos macios em relação aos duros. Correlação significativa foi encontrada entre FM e freqüência mastigatória no grupo com oclusão normal. Houve correlação significativa entre o FS e os parâmetros de mastigação. Meninas, crianças com maior FS e menor conteúdo de proteína tiveram maior porcentagem de acerto no sabor dos alimentos. Concluindo, houve relação entre FM e FS em crianças com oclusão normal, nas quais observou-se que a maior FM está relacionada a maior freqüência de mastigação de alimentos, o que indica facilidade de mastigação; o FS maior facilitou a mastigação e percepção do sabor de alimentos. / Abstract: Several are the factors that seem to intefeer on mastication: bite force (which might be related to the size of the muscles), components and quatity of saliva, occlusion caracteristics, among other. This thesis is composed by five chapters. Chapter 1 "The use of ultrasound in the investigation of the muscles of mastication" did a literature review about the use of ultrasonography on the investigation of the muscles of mastication and reinforced that US is a reliable method of great utility in the diagnostic field of alterations of the muscles of mastication and in the study of changes during growth and aging and that it remains as a promising technique for the study of the muscles of mastication. Chapter 2, "Correlation between muscle thickness and bite force in children before and after oral rehabilitation - a 2 year logitudinal study", evaluated the correlation between BF and muscle thickness before and after 6, 12, and 24 months of oral rehabilitation (TO, T6, T12, T24, respectively) in 19 6-9 years-old children with early loss of primary teeth. BF was determined with a flexible pressurized transducer. Masseter and temporal muscle thickness was measured during relaxation and maximal intercuspation by digital US with a high- resolution real-time 56mm/10-MHz linear-array transducer. There was a significant increase in BF and masseter thickness between TO and T12. There was a significant correlation between BF and relaxed and contracted temporal thickness at T6, and contracted temporal at T24. It was concluded that there was an increase in BF and masseter thickness after rehabilitation and there was also a relation between BF and temporal thickness, which suggests that the oral rehabilitation influences the morphological and functional aspects of the muscles of mastication. Chapters 3 "Bite force and salivary flow rate in schoolchildren", 4 "Bite force, texture perception and chewing parameters in schoolchildren" and 5 "Salivary flow rate, protein content, chewing parameters, and taste perception in schoolchildren" aimed to evaluate and correlate the salivary flow rate (SFR), BF, chewing parameters, perception of taste and texture of food, and the role of protein on mastication of children 7-10 years-old distributed according to occlusion and sex. BF was determined with a flexible pressurized transducer. Unstimulated (U) and stimulated (S) whole saliva were collected for 5 minutes in order to stablish the salivary flow rate (SFR), and the total protein was evaluated by method of Lowry et al. (1951). The following foods were tested: carrot, toast with and without margarine, banana, cheese, and chewing gum to determine the chewing parameters (chewing time, number of cycles and frequency), texture (using a visual analogue scale from 0 to 100 mm) and the taste (bitter, sour, sweet or salty). Boys presented SFR and BF (Chapter 3) significantly higher than girls. There was a significant correlation between SFR and BF for the group with normal occlusion. There was no significant difference in BF, texture or chewing parameters among groups of occlusion. Chewing parameters and texture were significantly lower for soft than hard foods. Significant correlation was found for BF and chewing frequency in the normal occlusion group. There was significant correlation between SFR and chewing parameters. Girls, children with higher SFR and lower protein content got more correct taste choices. Concluding, there was a relation between SFR and BF in children with normal occlusion, on whom a greater BF was related to a higher chewing frequency, which indicates facility of chewing; a higher SFR facilitated the mastication and taste perception of foods. / Doutorado / Odontopediatria / Doutor em Odontologia

Thesis (M.S.)--Air Force Institute of Technology, 2003. / Title from title screen (viewed July 1, 2004). "March 2003." Vita. "AFIT/GCA/ENV/03-04." "ADA415257"--URL. Includes bibliographical references (p. 71-74). Also issued in paper format.