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Incomplete fissures in severe emphysematous patients evaluated with MDCT: Incidence and interobserver agreement among radiologists and pneumologists

Koenigkam-Santos, Marcel; Puderbach, Michael; Gompelmann, Daniela; Eberhardt, Ralf; Herth, Felix; Kauczor, Hans-Ulrich; Heussel, Claus Peter
Fonte: ELSEVIER IRELAND LTD; CLARE Publicador: ELSEVIER IRELAND LTD; CLARE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.66%
Objective: Pulmonary fissures completeness predicts efficacy in endobronchial valves (EBV) implantation, a new lobar volume reduction therapy for severe emphysematous patients. We assessed the incidence of incomplete fissures and the interobserver agreement in its evaluation with MDCT, in severe emphysematous patients prior to EBV implantation. Materials and Methods: Volumetric thin-section CT scans of 35 patients (CODP GOLD 3/4, heterogeneous emphysema) were retrospectively reviewed by 2 pneumologists, 1 general and 2 experienced chest radiologists, independently and blinded for treatment outcome, and the pulmonary fissures were classified as either complete or incomplete. Interobserver agreement was assessed with Kappa index (KI). Results: Agreement between all readers for the left oblique, right oblique and horizontal fissure was, respectively, moderate (KI = 0.53), fair (KI = 0.37) and moderate (KI = 0.42). Highest agreement (99/105 fissures) was observed among experienced radiologists, being for left oblique, right oblique and horizontal, respectively, almost perfect (KI = 0.79), perfect (KI = 1.0) and moderate (KI = 0.52). These 2 reviewers found that all of 35 patients had at least one incomplete fissure, with a proportion of incomplete fissures assigned as 74/65%...

Using X rays to evaluate fissures in rice seeds dried artificially; Utilização de raios X na avaliação de fissuras em sementes de arroz submetidas à secagem artificial

Menezes, Nilson Lemos de; Cicero, Silvio Moure; Villela, Francisco Amaral; Bortolotto, Rafael Pivotto
Fonte: Associação Brasileira de Tecnologia de Sementes Publicador: Associação Brasileira de Tecnologia de Sementes
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.56%
The objective of the present study was to evaluate the efficiency of X-rays in identifying fissures in artificially dried rice seeds and the relationship between damage and seed performance in the germination test. Irrigated rice seeds of the IRGA 417 and IRGA 420 cultivars were harvested with 23.3 and 24.5% water content respectively and submitted to stationary drying treatments at 32, 38, 44 and 50 °C. X-rays were taken of subsamples of 100 seeds for each treatment, using an MX-20 X-ray equipment. The X-rayed seeds were classified from 1 to 3, where 1 corresponded to seeds without fissures, 2 to seeds with non-severe fissures and 3 to seeds with severe fissures. The same X-rayed seeds were planted and on the seventh day the seedlings (normal or abnormal) and dead seeds were photographed and evaluated to verify any relationship between the fissures and physiological potential. Higher drying temperature increased the percentage of fissures in the two cultivars, which can adversely affect their germination. Seeds with fissures can be identified using X-rays.

Reprodutibilidade e correlação in vivo dos métodos visuais e de fluorescência a laser na detecção de descolorações em sulcos e fossetas oclusais de molares decíduos; In vivo reproducibility and correlation of visual and laser fluorescence methods for the detection of pits and fissures with discoloration in primary molars

Nassif, Alessandra Cristina da Silva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 13/12/2006 PT
Relevância na Pesquisa
37.38%
Com o intuito de estudar in vivo a reprodutibilidade e a comparação de dois índices visuais (Ekstrand et al. (1998) ? E e Nyvad; Machiulskiene e Baelum (1999) ? N) e as medidas de fluorescência a laser AGNOdent®,KaVo - DD) na detecção de sulcos e fossetas descoloridos, um único examinador treinado, após a obtenção do consentimento livre e esclarecido de 28 pacientes, atribuiu os escores E, N e médias de fluorescência a laser de 190 molares decíduos com e sem descoloração em sulcos e fossetas oclusais. A reprodutibilidade dos índices visuais foi calculada a partir do teste kappa Cohen e kappa ponderado (kp), enquanto para as médias do DD foi calculado o índice de correlação de Pearson (rp). Para a comparação entre os índices visuais ainda se calculou a correlação de Spearman (rcs) e para a correlação entre os índices visuais e as médias do DD, foram aplicados o teste t de Student para as dicotomizações de presença de lesão, descoloração e atividade. Finalmente, foi calculada a análise de variância (ANOVA) para comparação entre as médias do DD e os graus de severidade das lesões. A reprodutibilidade dos índices visuais foi substancial (kpE = 0,645) e (kpN = 0,634) e as médias do DD apresentaram correlação de Pearson significativa e altamente positiva (rp = 0...

Avaliação in vitro e in situ da eficácia de diferentes lasers no aumento da resistência ácida do esmalte em regiões de sulcos e fissuras; In vitro and in situ assessment of lasers to increase enamel acid resistance on the pits and fissures surface.

Afonso, Alessandra Marques Corrêa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/12/2009 PT
Relevância na Pesquisa
37.27%
O objetivo desse estudo foi avaliar in vitro e in situ a efetividade de irradiação dos lasers Er:YAG, Nd:YAG e CO2 no aumento da resistência ácida do esmalte em regiões de sulcos e fissuras. Para o estudo in vitro foram utilizados molares humanos em fragmentos da porção oclusal de 8mmx4mm divididos em 3 grupos de acordo com o tipo de tratamento : Grupo 1 - Er:YAG; Grupo 2 - Nd:YAG; Grupo 3 - CO2 (n=15). O tratamento de superfície foi feito apenas em metade da área do fragmento, sendo que a outra metade foi considerada controle. As áreas expostas ao desafio cariogênico (14mm2) foram submetidas a ciclagens de pH. Para o testede microdureza os espécimes foram seccionados ao meio e a parede da secção é que sofreu o teste, a outra metade foi utilizada para análise em microscopia de luz polarizada para a medição da área da lesão de desmineralização e análise em MEV para verificar as alterações na morfologia do tecido dentário. As análises dos dados de microdureza (HKN) e área das lesões (mm2) foram feitas com o teste de Wilcoxon para a comparação interna de cada grupo com o seu controle e a comparação entre os grupos utilizou ANOVA para as áreas das lesões e Kruskal Wallis para a microdureza (α = 5%). Foi observada apenas diferença estatística significante para as amostras do grupo irradiado com laser CO2 entre as partes controle e experimental. Os demais grupos não apresentaram diferença estatisticamente significante com sua área controle. Na análise das medidas de lesão foram observadas diferença estatística significante para as amostras do grupo irradiado com os lasers CO2 e Nd:YAG com suas partes controles...

Penetration of a light-cured glass ionomer and a resin sealant into occlusal fissures and etched enamel.

Percinoto, C.; Cunha, R. F.; Delbem, A. C.; Aragones, A.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 20-22
ENG
Relevância na Pesquisa
37.56%
PURPOSE: To evaluate the penetration of a light-cured glass ionomer and a resin sealant into occlusal fissures and etched enamel. MATERIALS AND METHODS: Forty-eight maxillary and mandibular caries-free premolars scheduled for extraction for orthodontic reasons were isolated, the occlusal surfaces subjected to prophylaxis and acid-etched with orthophosphoric acid prior to the application of the VariGlass VLC glass ionomer and Concise resin sealants. The teeth were extracted, two longitudinal median sectiors from each tooth were ground to a thickness of 80-100 microns, and the sealant penetration into the fissures evaluated. The sections were placed in nitric acid to dissolve the enamel so the lengths of the tags which had penetrated into the etched enamel could be measured at different sites on the walls of the fissures. RESULTS: Both sealants adapted well to the fissures but penetrated deeper into shallow, open fissures than into deep, constricted fissures. The VariGlass VLC tags into etched enamel were generally longer than the Concise projections.

Aspectos clínico, radiográfico e microbiológico da pigmentação em molares decíduos sob monitoramento preventivo: estudo longitudinal

Silva, Janaína Zavitoski da
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: 139 f. : il. + 1 CD-ROM
POR
Relevância na Pesquisa
27.38%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Ciência Odontólogica - FOA; Este estudo verificou os aspectos clínico, radiográfico e microbiológico da pigmentação de fossas e fissuras pigmentadas em molares decíduos no período de 18 meses. Observou-se o dente e a superfície dentária mais acometidos pela pigmentação, a distribuição da mesma na superfície, a cor, a ocorrência de cavitação, a textura, a presença ou não de radioluscência, tipo de tratamento, bem como os microrganismos mais frequentes. Participaram do estudo 116 pacientes (63-grupo experimental e 53-grupo controle). Em 155 molares decíduos de 63 pacientes (grupo experimental) na faixa etária de 3 a 10 anos, foi realizada a coleta de biofilme, exame clínico nas fossas e fissuras pigmentadas, bem como exame radiográfico interproximal. Realizou-se a análise qualitativa de microrganismos das fossas e fissuras pigmentadas por meio do PCR convencional e quantitativa dos cocos cariogênicos (Streptococcus mutans e Streptococcus sobrinus) por “Real-Time PCR”. A análise estatística utilizou o software Statistica versão 9 aplicando os testes do quiquadrado, de correlação linear, de Komolgorov-Smirnov e Lilliefors e coeficiente de concordância de Kendall. O nível de significância foi de 5%. Observou-se que os dentes mais acometidos pela pigmentação nas fossas e fissuras foram os segundos molares...

Endobronchial valves in severe emphysematous patients: CT evaluation of lung fissures completeness, treatment radiological response and quantitative emphysema analysis

Koenigkam-Santos,Marcel; Paula,Wagner Diniz de; Gompelmann,Daniela; Kauczor,Hans-Ulrich; Heussel,Claus Peter; Puderbach,Michael
Fonte: Colégio Brasileiro de Radiologia e Diagnóstico por Imagem Publicador: Colégio Brasileiro de Radiologia e Diagnóstico por Imagem
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2013 EN
Relevância na Pesquisa
27.51%
OBJECTIVE: To evaluate lung fissures completeness, post-treatment radiological response and quantitative CT analysis (QCTA) in a population of severe emphysematous patients submitted to endobronchial valves (EBV) implantation. MATERIALS AND METHODS: Multi-detectors CT exams of 29 patients were studied, using thin-section low dose protocol without contrast. Two radiologists retrospectively reviewed all images in consensus; fissures completeness was estimated in 5% increments and post-EBV radiological response (target lobe atelectasis/volume loss) was evaluated. QCTA was performed in pre and post-treatment scans using a fully automated software. RESULTS: CT response was present in 16/29 patients. In the negative CT response group, all 13 patients presented incomplete fissures, and mean oblique fissures completeness was 72.8%, against 88.3% in the other group. QCTA most significant results showed a reduced post-treatment total lung volume (LV) (mean 542 ml), reduced EBV-submitted LV (700 ml) and reduced emphysema volume (331.4 ml) in the positive response group, which also showed improved functional tests. CONCLUSION: EBV benefit is most likely in patients who have complete interlobar fissures and develop lobar atelectasis. In patients with no radiological response we observed a higher prevalence of incomplete fissures and a greater degree of incompleteness. The fully automated QCTA detected the post-treatment alterations...

Using X rays to evaluate fissures in rice seeds dried artificially

Menezes,Nilson Lemos de; Cicero,Sílvio Moure; Villela,Francisco Amaral; Bortolotto,Rafael Pivotto
Fonte: Associação Brasileira de Tecnologia de Sementes Publicador: Associação Brasileira de Tecnologia de Sementes
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
27.56%
The objective of the present study was to evaluate the efficiency of X-rays in identifying fissures in artificially dried rice seeds and the relationship between damage and seed performance in the germination test. Irrigated rice seeds of the IRGA 417 and IRGA 420 cultivars were harvested with 23.3 and 24.5% water content respectively and submitted to stationary drying treatments at 32, 38, 44 and 50 °C. X-rays were taken of subsamples of 100 seeds for each treatment, using an MX-20 X-ray equipment. The X-rayed seeds were classified from 1 to 3, where 1 corresponded to seeds without fissures, 2 to seeds with non-severe fissures and 3 to seeds with severe fissures. The same X-rayed seeds were planted and on the seventh day the seedlings (normal or abnormal) and dead seeds were photographed and evaluated to verify any relationship between the fissures and physiological potential. Higher drying temperature increased the percentage of fissures in the two cultivars, which can adversely affect their germination. Seeds with fissures can be identified using X-rays.

The effects of dietary biotin supplementation on vertical fissures of the claw wall in beef cattle.

Campbell, J R; Greenough, P R; Petrie, L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /09/2000 EN
Relevância na Pesquisa
27.45%
A clinical field trial was performed on a herd of Hereford beef cows in central Saskatchewan. The herd had a history of being severely affected with vertical fissures. The objective of the study was to determine the effects of supplemental dietary biotin on the prevalence of vertical fissures in beef cows. In June 1994 and June 1995, 1- and 2-year-old heifers were randomly allocated into 2 treatment groups, each composed of 79 animals. One group received a 10 mg/head/day biotin-supplemented free-choice mineral supplement, while the other groups received an identical free-choice mineral without the biotin supplementation. The claws from these animals were evaluated in June 1994, October 1994, June 1995, October 1995, and June 1996 for the presence of vertical fissures. Supplemental dietary biotin significantly increased serum levels of biotin and significantly increased claw hardness in supplemented cows. Both groups of heifers started the trial without vertical fissures. After 18 months, 15% of the cows fed supplemental dietary biotin had vertical fissures compared with 33% in the nonsupplemented group. The difference was statistically significant (P = 0.01).

Randomised controlled trial shows that glyceryl trinitrate heals anal fissures, higher doses are not more effective, and there is a high recurrence rate

Carapeti, E; Kamm, M; McDonald, P; Chadwick, S; Melville, D; Phillips, R
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1999 EN
Relevância na Pesquisa
27.38%
BACKGROUND—Topical application of glyceryl trinitrate (GTN) ointment heals chronic anal fissures, providing an alternative to the traditional first line treatment of surgical sphincterotomy. 
AIMS—To determine the most effective dose of topical GTN for treatment of chronic anal fissures and to assess long term results. 
METHODS—Seventy consecutive patients with chronic anal fissure, were randomly allocated to eight weeks treatment with placebo, 0.2% GTN three times daily, or GTN starting at 0.2% with weekly 0.1% increments to a maximum of 0.6%, in a double blind study. 
RESULTS—After eight weeks fissure had healed in 67% of patients treated with GTN compared with 32% with placebo (p=0.008). No significant difference was seen between the two active treatments. Headaches were reported by 72% of patients on GTN compared with 27% on placebo (p<0.001). Maximum anal sphincter pressure reduced significantly from baseline by GTN treatment (p=0.02), but not placebo (p=0.8). Mean pain scores were lower after treatment with GTN compared with placebo (NS). Of fissures healed with placebo 43% recurred, compared with 33% of those healed with 0.2% GTN and 25% healed with escalating dose GTN (p=0.7). 
CONCLUSIONS—GTN is a good first line treatment for two thirds of patients with anal fissure. An escalating dose of GTN does not result in earlier healing. Significant recurrence of symptomatic fissures and a high incidence of headaches are limitations of the treatment. 



A dose finding study with 0.1%, 0.2%, and 0.4% glyceryl trinitrate ointment in patients with chronic anal fissures

Scholefield, J H; Bock, J U; Marla, B; Richter, H J; Athanasiadis, S; Pröls, M; Herold, A
Fonte: Copyright 2003 by Gut Publicador: Copyright 2003 by Gut
Tipo: Artigo de Revista Científica
Publicado em /02/2003 EN
Relevância na Pesquisa
27.38%
Background: Anal fissure is a common painful condition affecting the anal canal. The majority of acute fissures heal spontaneously. However, some of these acute fissures do not resolve but become chronic. Chronic anal fissures were traditionally treated by anal dilation or by lateral sphincterotomy. However, both of these surgical treatments may cause a degree of incontinence in up to 30% of patients. Several recent trials have shown that nitric oxide donors such as glyceryl trinitrate (GTN) can reduce sphincter pressure and heal up to 70% of chronic fissures.

Identification of Pulmonary Fissures Using a Piecewise Plane Fitting Algorithm

Gu, Suicheng; Wilson, David; Wang, Zhimin; Bigbee, William L.; Siegfried, Jill; Gur, David; Pu, Jiantao
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.51%
We describe an automated computerized scheme to identify pulmonary fissures depicted in chest computed tomography (CT) examinations from a novel perspective. Whereas CT images can be regarded as a cloud of points, the underlying idea is to search for surface-like structures in the three dimensional (3D) Euclidean space by using an efficient plane fitting algorithm. The proposed plane fitting operation is performed in a number of small spherical lung sub-volumes to detect small planar patches. Using a simple clustering criterion based on their spatial coherence and surface area, the identified planar patches, assumed to represent fissures, are classified into different types of fissures, namely left oblique, right oblique and right horizontal fissures. The performance of the developed scheme was assessed by comparing with a manually created “reference standard” and the results obtained by a previously developed approach on a dataset of 30 lung CT examinations. The experiments show that the average discrepancy is around 1.0 mm in comparison with the reference standard, while the corresponding maximum discrepancy is 20.5 mm. In addition, 94% of the fissure voxels identified by the computerized scheme are within 3 mm of the fissures in the reference standard. As compared to a previously developed approach...

Non-Azygos Accessory Fissure in Right Upper Lobe Associated with Superior and Inferior Accessory Fissures in Right Lower Lobe

Muttikkal, Thomas Jose Eluvathingal; Deng, Chunli
Fonte: Medknow Publications & Media Pvt Ltd Publicador: Medknow Publications & Media Pvt Ltd
Tipo: Artigo de Revista Científica
Publicado em 27/12/2012 EN
Relevância na Pesquisa
27.38%
Accessory fissures in the lungs are common congenital variations, usually detected as incidental findings in radiographs or CT scan. Accessory fissures can act as an anatomic barrier to the spread of inflammatory or neoplastic disease, as well as due to the variant anatomy, mimic lesions. It is important to recognize the presence of accessory fissures, as they affect surgical planning of pulmonary lobectomy and segmentectomy. Accessory fissure in the right upper lobe other than due to the anomalous course of azygos vein is very rare. We report a case of non-azygos accessory fissure, between the apical and the anterior segments of right upper lobe, along with superior and inferior accessory fissures in the right lower lobe.

Automatic Segmentation of Pulmonary Fissures in Computed Tomography Images Using 3D Surface Features

Yu, Mali; Liu, Hong; Gong, Jianping; Jin, Renchao; Han, Ping; Song, Enmin
Fonte: Springer US Publicador: Springer US
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.38%
Pulmonary interlobar fissures are important anatomic structures in human lungs and are useful in locating and classifying lung abnormalities. Automatic segmentation of fissures is a difficult task because of their low contrast and large variability. We developed a fully automatic training-free approach for fissure segmentation based on the local bending degree (LBD) and the maximum bending index (MBI). The LBD is determined by the angle between the eigenvectors of two Hessian matrices for a pair of adjacent voxels. It is used to construct a constraint to extract the candidate surfaces in three-dimensional (3D) space. The MBI is a measure to discriminate cylindrical surfaces from planar surfaces in 3D space. Our approach for segmenting fissures consists of five steps, including lung segmentation, plane-like structure enhancement, surface extraction with LBD, initial fissure identification with MBI, and fissure extension based on local plane fitting. When applying our approach to 15 chest computed tomography (CT) scans, the mean values of the positive predictive value, the sensitivity, the root–mean square (RMS) distance, and the maximal RMS are 91 %, 88 %, 1.01 ± 0.99 mm, and 11.56 mm, respectively, which suggests that our algorithm can efficiently segment fissures in chest CT scans.

The Engrailed Homeobox genes are required in multiple cell lineages to coordinate sequential formation of fissures and growth of the cerebellum

Orvis, Grant D.; Hartzell, Andrea L.; Smith, Jenessa B.; Barraza, Luis Humberto; Wilson, Sandra L.; Szulc, Kamila U.; Turnbull, Daniel H.; Joyner, Alexandra L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.6%
The layered cortex of the cerebellum is folded along the anterior-posterior axis into lobules separated by fissures, allowing the large number of cells needed for advanced cerebellar functions to be packed into a small volume. During development, the cerebellum begins as a smooth ovoid structure with two progenitor zones, the ventricular zone and upper rhombic lip, which give rise to distinct cell types in the mature cerebellum. Initially, the cerebellar primordium is divided into five cardinal lobes, which are subsequently further subdivided by fissures. The cellular processes and genes that regulate the formation of a normal pattern of fissures are poorly understood. The engrailed genes (En1 and En2) are expressed in all cerebellar cell types and are critical for regulating formation of specific fissures. However, the cerebellar cell types that En1 and En2 act in to control growth and/or patterning of fissures has not been determined. We conditionally eliminated En2 or En1 and En2 either in both progenitor zones and their descendents or in the two complementary sets of cells derived from each progenitor zone. En2 was found to be required only transiently in the progenitor zones and their immediate descendents to regulate formation of three fissures and for general growth of the cerebellum. In contrast...

Tensional fissures and crustal extension rates in the northern part of the Main Ethiopian Rift

Williams, F.; Williams, M.; Aumento, F.
Fonte: Pergamon Publicador: Pergamon
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
Relevância na Pesquisa
37.27%
This paper describes a swarm of tensional fissures located at the northern end of the Main Ethiopian Rift, and attempts to relate their dimensions and age to the overall rate of Rift widening. The fissures dissect an otherwise undisturbed welded tuff formation associated with the caldera complex of Mount Fantale. This tuff was dated by the fission track method to 168,000 ± 38,000 years. Examination of a comparable single fissure dissecting welded tuff and radiocarbon dated sediments at nearby K’one caldera complex suggests that the fissuring episode occurred within the last 7000 years. Detailed measurement of the total extension across the fissure swarm, taken in conjunction with these ages, indicates an average rate of widening of 0.01 cm per year across the 20 km width of the welded tuff. The overall extension rate of the rift at this latitude as determined by plate tectonic modelling is of the order of 0.5 cm per year, and by geodetic measurements between 0.1 and 0.45 cm per year. This marked discrepancy reflects the different scales of time and distance over which the various means of measurement operate. It indicates that the extension process is very variable over both time and space, and that surface evidence of extension may not be immediately apparent.; F.M. Williams...

Mineralization of human premolar occlusal fissures. A quantitative histochemical microanalysis

Campos, A.; Rodriguez, I.A.; Sanchez-Quevedo, M.C.; García, J.M.; Nieto-Albano, O.H.; Gómez de Ferraris, M.E.
Fonte: Murcia : F. Hernández Publicador: Murcia : F. Hernández
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
27.51%
The mechanisms of cariogenesis in occlusal fissures remain elusive because of limited information about fissure structure and wall mineralization. The purpose of the present study was to determine the correlation between morphological patterns in occlusal fissures in human premolars and quantitative histochemical patterns of mineralization in the walls of these formations. We used scanning electron microscopy and quantitative X-ray microanalysis with the peak-tolocal background ratio method and microcrystalline calcium salts as standards. We distinguished three morphological patterns of fissures in scanning electron microscopic images. The wall of the fissures was less mineralized than the control enamel in all three types of fissures. Because the fissure walls are hypomineralized, we suggest that practicing dentists should take into account the degree of mineralization when they are preparing the fissures for the application of sealant.

Mineralization of human premolar occlusal fissures: a quantitative histochemical microanalysis

Campos Mu??oz, Antonio; Rodr??guez, Ismael ??ngel; S??nchez Quevedo, Mar??a del Carmen; Garc??a L??pez, Jos?? Manuel; Nieto Albano, O. H.; G??mez de Ferraris, Mar??a Elsa
Fonte: Universidad de Murcia Publicador: Universidad de Murcia
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.56%
The mechanisms of cariogenesis in occlusal fissures remain elusive because of limited information about fissure structure and wall mineralization. The purpose of the present study was to determine the correlation between morphological patterns in occlusal fissures in human premolars and quantitative histochemical patterns of mineralization in the walls of these formations. We used scanning electron microscopy and quantitative X-ray microanalysis with the peak-tolocal background ratio method and microcrystalline calcium salts as standards. We distinguished three morphological patterns of fissures in scanning electron microscopic images. The wall of the fissures was less mineralized than the control enamel in all three types of fissures. Because the fissure walls are hypomineralized, we suggest that practicing dentists should take into account the degree of mineralization when they are preparing the fissures for the application of sealant.

Thickening of pulmonary interlobar fissures: exposure-response relationship in crocidolite and amosite miners

Solomon, A.; Irwig, L. M.; Sluis-Cremer, G. K.; Thomas, R. Glyn; Toit, R. S. J. Du
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1979 EN
Relevância na Pesquisa
27.51%
ABSTRACT In a cross-sectional study of all white and mixed-race men employed at South African crocidolite and amosite mines, data on duration of asbestos exposure and radiological findings were available for 162 men, 94% of the total population. Postero-anterior radiographs were read by three experienced readers. Abnormality was regarded as present if reported by at least two of them. The reading included an assessment of whether interlobar fissures were not visible, were visible but not thickened, or were thickened according to criteria shown in a reference radiograph. Fissures which were visible but not thickened were seen in almost half the men and were not more common in men with longer asbestos exposure. On the other hand, thickened fissures increased in prevalence from about 2% in those who had worked with asbestos for 7 years or less, to 25% in those with more than 15 years' asbestos exposure. Some other asbestos-associated pleural or parenchymal abnormality occurred in 69% of men with thickened fissures. The prevalence of thickened fissures as an isolated abnormality was also related to the duration of asbestos exposure. Because its prevalence is related to duration of exposure, and its recognition is not subject to excessive inter-observer variation...

Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary

Hauksson, Egill
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 10/01/1983
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The rifting of the plate boundary in north Iceland forms new ground fissures and reactivates old ones. Continuous growth of fissures is observed in the crust above a magma chamber beneath the Krafla caldera as it responds to changes in subterranean magma pressure. Rapid episodes of fissure formation and reactivation are observed in conjunction with magma intrusions at depth along the rift zone that constitutes the plate boundary between the North American and Eurasian plates. The Krafla caldera contains several fissures that open during periods of uplift lasting 100 to 300 days and that close incompletely in subsidence episodes lasting several hours to 3 weeks. The average rate of opening differs from one period to another, ranging from 0.1 to 0.5 mm/d. Fissure closing and average closing rates also vary from one subsidence episode to another, ranging from minimal values of 2.1 mm and 2.3 mm/d to maximal values of 49 mm and 18 mm/d, respectively. During the two intrusion episodes of September 1977 and March 1980 the magma migrated toward the south with an average velocity 0.6 and 0.5 m/s, respectively. In the September 1977 episode some fissures in the rift zone widened with a rate greater than 190 mm/d, whereas during the March episode that probably resulted in a thinner intrusion the maximum widening rate was only 50 mm/d. The data suggest that the magnitude of a subsidence episode is determined at least partly by the available excess magma pressure in the chamber. To explain the extensive growth of open fissures and normal faulting in the rift zone...