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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Precisão de medidas lineares em imagens tomograficas

Guedes, Fabio Ribeiro 24 February 2005 (has links)
Orientador: Glaucia Maria Bovi Ambrosano / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T03:10:26Z (GMT). No. of bitstreams: 1 Guedes_FabioRibeiro_M.pdf: 16708948 bytes, checksum: 136372754eec5ecaf8e3293298f9b330 (MD5) Previous issue date: 2005 / Resumo: Foi identificado o fator de magnificação de tomógrafos convencionais e comparado a mangnificação fornecida pelos fabricantes, e a confiabilidade de medidas lineares das imagens tomográficas corrigidas, quando comparadas às mensurações reais nos segmentos ósseos. Foram utilizadas 16 mandíbulas humanas maceradas edêntulas, e selecionada região correspondente aos incisivos, caninos, pré-molares e molares bilateralmente. Em cada região foram fixados sobre a crista óssea e na região vestibular, um fio ortodôntico com 5,0 milímetros de comprimento, que foi utilizado como guia radiográfico. Os equipamentos utilizados neste trabalho foram os tomógrafos convencionais Quint Sectograph, Orthopantomograph OP100, X Mind TOME, e computadorizados Somatom Esprit com reconstrução multiplanar e Toshiba X vision EX com software Denta Scan. As mandíbulas foram posicionadas nos tomógrafos convencionas conforme as especificações dos fabricantes e obtidas as imagens. Para os tomógrafos computadorizados as mandíbulas foram posicionadas com suas bases perpendiculares ao solo e obtidas as imagens axiais ara posterior reconstrução oblíquo-sagital das regiões. Após obtidas as imagens, foram mensuradas a altura e espessura óssea de cada região, corrigindo-se as medidas com base a ampliação do guia radiográfico e em seguida com o fator de magnificação dado pelo fabricante. As mandíbulas foram seccionadas exatamente nas regiões selecionadas, e realizadas as medidas da altura e espessura óssea, obtendo-se os valores reais por região. As magnificações calculadas, por meio do guia radiográfico dos tomógrafos convencionais, foram comparados pelo teste t, com os fornecidos pelos fabricantes, observando-se diferenças significativas para os três tomógrafos convencionais. A altura e espessura óssea corrigidas pela ampliação do guia radiográfico apresentaram diferenças estatisticamente significativas (p<0,05) pelo teste de Dunnett para as medidas do tomógrafo computadorizado Somatom Esprit quando comparadas com as dimensões reais. A medida da altura óssea corrigida com o fator de magnificação fornecido pelo fabricante demonstrou diferenças para os tomógrafos (p<0,05) com exceção do tomógrafo computadorizado Toshiba X vision EX, e para espessura óssea observou-se diferenças para o tomógrafo Quint Sectograph e Somatom Esprit quando comparados com as dimensões reais (p<0,05). Concluiu-se que as diferenças de magnificação calculadas, comparadas com as fornecidas pelos fabricantes não possuem significância clínica. As mensurações da altura e espessura ósseas foram precisas com exceção das realizadas no tomógrafo computadorizado com reconstrução multiplanar Somatom Sprit / Abstract: The magnification factors of conventional tomography was identified and compared them to the factors provided by the manufacturers, and the reliability of linear measurements achieved on corrected tomographic images, when compared to the real measurements on the bone segments. Sixteen dry edentulous human mandibles were used, and the area corresponding to the incisors, canines, premolars and molars were selected bilaterally. A 5.0-mm long orthodontic wire was fixated on the bone crest and buccal region of each area, to be used as a radiographic guide. The equipments used in this study were the conventional tomography Quint Sectograph, Orthopantomograph OP100, X Mind TOME, and the computerized tomography Somatom Esprit with multiplanar reconstruction and Toshiba X Vision EX with the Denta Scan software. The mandibles were positioned on the conventional scanners following the manufacturers¿ instructions, and the images were obtained. As to the computerized scanners, the mandibles were positioned with their bases perpendicular to the ground, and axial images were achieved for later oblique-sagittal reconstruction of the regions. After achievement of the images, the bone height and thickness of each region were measured, with correction of measurements based on the magnification of the radiographic guide and then according to the magnification factor supplied by the manufacturer. The mandibles were sectioned at the selected areas and bone height and thickness were directly measured, for achievement of the real values for each region. The magnification factors calculated by utilization of the radiographic guide for the conventional tomography were compared to those provided by the manufacturers by the t test, which revealed significant differences for the three conventional scanners. The bone height and thickness with correction according to magnification of the radiographic guide presented statistically significant differences (p<0.05) according to the Dunnett test for the measurements achieved on the computerized tomography Somatom Esprit compared to the real dimensions. The bone height corrected according to the magnification factor provided by the manufacturer demonstrated differences for the scanners (p<0.05), except for the computerized tomography Toshiba X vision EX, with differences in bone thickness for the Quint Sectograph and Somatom Esprit tomography compared to the real dimensions (p<0.05). It was concluded that differences between the magnification factors calculated compared to those provided by the manufacturers do not have any clinical implication; also, measurements of bone height and thickness were reliable, except for those achieved on the computerized tomography with multiplanar reconstruction Somatom Sprit / Mestrado / Radiologia Odontologica / Mestre em Radiologia Odontológica
272

Analise fotoelastica da distribuição de tensões induzidas por infra-estruturas implanto-suportadas apos soldagem a laser ou retificação de cilindros

Damaceno, Alessandra Regina Derogis 02 March 2005 (has links)
Orientador: Mauro Antonio de Arruda Nobilo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T03:53:51Z (GMT). No. of bitstreams: 1 Damaceno_AlessandraReginaDerogis_M.pdf: 1414206 bytes, checksum: c7d213655bfe8d988e6311566b91787d (MD5) Previous issue date: 2005 / Resumo: Este estudo avaliou comparativamente duas técnicas indicadas para a obtenção de melhor assentamento de próteses implanto-suportadas através da análise fotoelástica. Para isso, foram obtidos dois grupos de infra-estruturas metálicas em titânio construídas sobre uma matriz metálica com forma e dimensões similares ao arco mandibular, sendo: Grupo 1- três infra-estruturas confeccionadas pela técnica da soldagem de borda a laser de cilindros pré-fabricados; Grupo 2- três infra-estruturas fundidas em monobloco e submetidas ao sistema de retificação de cilindros fundidos. Após avaliação em microscopia óptica, apenas a infra-estrutura mais bem adaptada de cada grupo foi submetida à análise fotoelástica variando-se três seqüências de aperto dos parafusos (1/2/3/4/5, 5/4/3/2/1 e 3/2/4/1/5). De maneira adicional, a infra-estrutura representante do grupo 2 foi submetida, após a primeira análise, à secção e soldagem vertical das partes, e reavaliada. Os resultados mostraram formação de maior quantidade de tensões nas seqüências de aperto 1/2/3/4/5 e 5/4/3/2/1, para ambos os grupos analisados. A estrutura submetida à soldagem de borda de cilindros pré-fabricados mostrou melhores resultados, apesar de a mesma apresentar maiores valores de desadaptação (165µm) quando comparada àquela que teve seus cilindros submetidos à retificação de borda antes (54µm) ou após a secção e soldagem vertical (117µm). A seqüência de aperto 3/2/4/1/5 mostrou melhores resultados. Portanto, o grupo dos cilindros submetidos à soldagem de borda induziu melhores resultados principalmente quando associada à seqüência de aperto 3/2/4/1/5 / Abstract: This study evaluated two techniques indicated to obtain implant-supported fixed prostheses with satisfactory passive fit by means of photoelastic analysis. Two titanium casts groups were fabricated in a metallic master cast: Group I ¿ three frameworks fabricated by laser welded cylinder technique and Group II ¿ three frameworks cast in one-piece and submitted to Rectification Cylinder System. After optical microscopy evaluation, only the better-fit framework of both groups was submitted to the photoelastic analysis, testing three screw tightening sequences (5/4/3/2/1; 1/2/3/4/5 and 3/2/4/1/5). Subsequent to the first analysis, the selective framework of Group II was sectioned and laser welded to be submitted to a new evaluation. Results showed superior stress magnitude in 1/2/3/4/5 and 5/4/3/2/1 sequences of both groups, while 3/2/4/1/5 screw tightening sequence presented better stress results of them. Laser welded cylinder framework illustrated better results, even though had showed superior values of misfit (165µm) compared to the rectified framework before (54µm) and after section and vertical laser welded (117µm). Laser welded cylinder group achieved better results mainly allied to 3/2/4/1/5 screw tightening sequence / Mestrado / Protese Dental / Mestre em Clínica Odontológica
273

The role of toll-like receptors in assisted conception

Aboussahoud, Wedad January 2016 (has links)
Background: In the last two decades the discovery of the Toll-Like Receptor (TLR) family in humans revealed the importance of innate immunity in providing host defence against invading pathogens. Moreover, TLRs have a vital role in mediating the interactions between the reproductive and immune systems. Similar to TLRs, (NOD)-like receptors (NLRs); retinoic acid-inducible gene-1, RIG-1-like receptors (RLRs) are also important pattern recognition receptors in the female reproductive system. Successful implantation requires effective reciprocal interactions between receptive endometrium and competent embryo. The endometrial innate immunity during implantation has been intensively investigated. However, little is known about the expression of innate immunity during the early stages of human embryo development. Objective: To investigate the expression of innate immunity molecules during the early stages of human embryo development and to determine the functions of TLRs in blastocysts. Material and methods: The expression of TLRs, a panel of downstream signalling molecules, NLRs, RLRs, inflammatory cytokines, chemokines and the hyaluronic acid system were investigated in the following developmental stages: oocyte, 4- cell, blastomeres, 8- cell, blastocyst, inner cell mass and trophectoderm using Affymetrix Human Genome U133 Plus 2.0 arrays. Microarray data were validated by Q-PCR. TLR function in human blastocysts was investigated by treating day five blastocysts with TLR3 or TLR5 specific ligands; Poly (I:C) and flagellin respectively, for 24 hours. The culture media was analysed for elevated cytokine and chemokine levels using cytometric bead array. Results: TLRs, NLRs, RLRs, TLR downstream signalling molecules, cytokines and chemokines involved during implantation event and the hyaluronic system were all found to be positively expressed in the early stages of human embryo development. The expression levels of the above molecules were generally moderate to low (CT 24-34) and varied across the embryonic developmental stages. Stimulation of TLR3 and TLR5 in day 5 blastocysts produced cytokines and chemokines. In addition, there were alterations in gene expression patterns in the Poly (I:C) and flagellin treated blastocysts in comparison to the untreated blastocysts. Conclusion: The varied expression levels of the investigated molecules involved in early embryonic developmental suggests a potential role for these molecules in early pregnancy loss and implantation failure. Specifically, the relationship between the level of TLR expression, function and embryo quality is worth investigating in the future as a potential marker for embryo competence.
274

A Novel Process for GeSi Thin Film Synthesis

Hossain, Khalid 12 1900 (has links)
A unique process of fabricating a strained layer GexSi1-x on insulator is demonstrated. Such strained heterostructures are useful in the fabrication of high-mobility transistors. This technique incorporates well-established silicon processing technology e.g., ion implantation and thermal oxidation. A dilute GeSi layer is initially formed by implanting Ge+ into a silicon-on-insulator (SOI) substrate. Thermal oxidation segregates the Ge at the growing oxide interface to form a distinct GexSi1-x thin-film with a composition that can be tailored by controlling the oxidation parameters (e.g. temperature and oxidation ambient). In addition, the film thickness can be controlled by implantation fluence, which is important since the film forms pseudomorphically below 2×1016 Ge/cm2. Continued oxidation consumes the underlying Si leaving the strained GeSi film encapsulated by the two oxide layers, i.e. the top thermal oxide and the buried oxide. Removal of the thermal oxide by a dilute HF etch completes the process. Strain relaxation can be achieved by either of two methods. One involves vacancy injection by ion implantation to introduce sufficient open-volume within the film to compensate for the compressive strain. The other depends upon the formation of GeO2. If Ge is oxidized in the absence of Si, it evaporates as GeO(g) resulting in spontaneous relaxation within the strained film. Conditions under which this occurs have been discussed along with elaborated results of oxidation kinetics of Ge-ion implanted silicon. Rutherford backscattering spectrometry (RBS), ion channeling, Raman spectroscopy and scanning electron microscopy (SEM) were used as the characterization techniques.
275

Carbon, magnesium implantation and proton irradiation on pulsed laser deposited thermochromic thin film of VO2

Mabakachaba, Boitumelo Mafalo January 2020 (has links)
>Magister Scientiae - MSc / When the spacecrafts orbit in space, it is subjected to significant thermal cycling variation. Thermal regulation of the spacecraft temperature is required to ensure a good operation of the small crafts such as CubeSats and the on-board equipment while minimizing the weight. Three methods employed for the Smart Radiator Devices (SRD) are (i) mechanical louvers, (ii) electrochromic coatings and (iii) thermochromic coatings (which is of interest in this study). Based on the characteristics of the thermochromic coatings, the passive smart radiator device is by far the most efficient option since there are no mechanical moving components and also no electric energy needed for the craft to operate.
276

Effect of Platelet Activating Factor on Embryonic Development and Implantation in the Mouse

Fukuda, Aisaku I., Breuel, Kevin F. 01 January 1996 (has links)
Platelet activating factor (PAF) was administered to female mice in order to investigate its effect on ovulation rate and on oocyte quality including their in-vitro embryonic development, implantation and uterine receptivity. In experiment 1, 4-week-old female mice were assigned to receive PAF or phosphate buffered saline for 4 consecutive days. On the second day of this treatment, pregnant mares' serum gonadotrophin was administered and human chorionic gonadotrophin (HCG) 48 h later, after which copulation occurred. Oocytes were collected on the following day and evaluated. The mean number of oocytes and zygotes (two pronuclear stage embryos) recovered from the PAF-treated group was not diffferent from the control group (31 versus 27), but the proportion of zygotes was higher in PAF-treated group than in controls (83 versus 68%, P < 0.05, PAF versus controls). Although the rate of in-vitro first cleavage was not different in the two groups (82 versus 69% respectively), hatching was higher in the PAF-treated group than control mice (99 versus 83%, P < 0.01). In experiment 2, the in-vitro developed blastocysts from experiment 1 were transferred into the uterus of day 3 pseudopregnant PAF-treated or control recipients. Three different combinations of intrauterine transfer were performed; PAF embryo to control recipient (PAF → C: n = 19), control embryo to PAF recipient (C → PAF: n = 19), and control embryo to control recipient (C → C: n = 22). Implantation and abortion were assessed on day 19 post-transfer. The implantation rate of C → PAF (23.7%) was lower than C → C (31.1%, P < 0.05), but was not different from PAF → C (31.2%). Further, C → PAF showed a higher abortion rate per embryo (29.6%) than PAF → C (12.7%, P < 0.05), but was not different from C → C (24.4%). In the present study, PAF administration enables females to produce oocytes with a higher potential for fertilization, in vitro development and implantation, but has a detrimental effect on uterine receptivity to embryos.
277

Meta-Analysis of Behavior Problems in Deaf and Hard of Hearing Children

Tobenas, Marta Maria 01 January 2019 (has links)
Recent data regarding social-emotional challenges indicate elevations in behavior problems (BPs) in deaf and hard of hearing (DHH) children (Austen, 2010; Stevenson et al., 2010; van Eldik et al., 2004). Factors affecting this include family and social contexts, language development (LD), and cochlear implantation (CIs). The purpose of this dissertation was to analyze findings across studies for trends in BPs in DHH children. Specifically, a model of the effect of deafness, CI use, and LD on the emergence of BPs in DHH children as compared to hearing children was examined. Studies were collected through systematic searches of psychology databases supplemented by studies referenced in other sources therein discovered. Random-effects meta-analyses using the restricted maximum likelihood estimation method were non-significant (g = 0.31, SE = 0.20, CI [-0.09, 0.71]), as were subgroup analyses (g = 0.36, SE = 0.22, CI [-0.07, 0.80]). A metaregression using CIs as a predictor evidenced a nonsignificant reduction in BPs for deaf children with CIs and CIs did not significantly predict BPs in deaf children. Unexplained heterogeneity remained elevated in all cases (I2 above 96%). In sensitivity analyses, I2 decreased to 87%, suggesting that designs of included primary studies may have impacted those studies’ data collection, analysis, and interpretation. Unmeasured variables such as LD may explain much of the remaining heterogeneity. Collaborating with researchers worldwide, using more inclusive selection criteria, and enacting a longitudinal design could collect a greater variety of data, creating a more complete understanding of the effect of hearing loss on BPs.
278

The Germ Cell Fate of Cynomolgus Monkeys is Specified in the Nascent Amnion / カニクイザル生殖細胞は初期羊膜で形成される

Sasaki, Kotaro 23 May 2017 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13112号 / 論医博第2130号 / 新制||医||1022(附属図書館) / (主査)教授 浅野 雅秀, 教授 瀬原 淳子, 教授 近藤 玄 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM
279

A-674563 increases chondrocyte marker expression in cultured chondrocytes by inhibiting Sox9 degradation / A-674563はSox9蛋白質の分解を抑制することにより培養軟骨細胞の軟骨マーカーの発現を増加させる

Kobayashi, Tomohito 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21012号 / 医博第4358号 / 新制||医||1028(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 戸口田 淳也, 教授 鈴木 茂彦, 教授 開 祐司 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
280

Electrical conduction in carbon-ion implanted diamond and other materials at low temperatures.

Tshepe, Tshakane Frans January 1992 (has links)
A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science / The role of intersite electron correlation effects and the possible occurrence of the metal-insulator transition in carbon-ion implanted type IIa diamond samples have been studied at very low temperatures, using four- and two-point probe contact electrical conductivity measuring techniques. The measurements were extended to ruthenium oxide thin films in the presence and absence of a constant magnetic field of B = 4.0 T down to 100 mK, using a 3He-4He dilution refrigerator. The effect of the Coulomb gap in the variable range hopping regime has been well studied by other workers. The results tend to follow the Efros-Shklovskii behaviour with a trend towards the Mott T- 114 law for diamond samples far removed from the metal insulator transition, on the insulating side at low temperatures. / Andrew Chakane 2019

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