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Longitudinal Sections (longitudinal + section)
Selected AbstractsEvidence for axonemal distortion during the flagellar beat of ChlamydomonasCYTOSKELETON, Issue 8 2007Charles B. Lindemann Abstract In order to understand the working mechanism that governs the flagellar beat it is essential to know if the axoneme undergoes distortion during the course of the beat cycle. The rapid fixation method employed by Mitchell was able to preserve the waveform of Chlamydomonas flagella much as it appears during normal flagellar beating [Mitchell, Cell Motil Cytoskeleton 2003;56:120,129]. This conservation of the waveform suggests that the stress responsible for the production of bending is also trapped by the fixation procedure. Longitudinal sections of these well-preserved flagella were used to document variations in the relative axonemal diameter. Sections aligned to the plane of bending, showing both the central pair microtubules and outer doublets, were examined for this purpose. Micrographs were selected that continuously showed both the outer doublets and the central pair from a straight region to a curved region of the flagellum. Axoneme diameters measured from these select micrographs showed an increase in relative diameter that averaged 39 nm greater at the crest of the bent region. This constituted a 24% increase in the axoneme diameter in the bends. The transverse stress acting across the axoneme during bending was calculated from the Geometric Clutch computer model for a simulated Chlamydomonas -like flagellar beat. If we assume that this is representative of the transverse stress acting in a real flagellum, then the Young's modulus of the intact axoneme is ,0.02 MPa. The possibility that the distortion of the axoneme during the beat could play a significant role in regulating dynein function is discussed. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] An in vitro study of non-axial forces upon the retention of an O-ring attachmentCLINICAL ORAL IMPLANTS RESEARCH, Issue 12 2009Renata Cristina Silveira Rodrigues Abstract: Objective: The purpose of this study was to evaluate the retention force of an O-ring attachment system in different inclinations to the ideal path of insertion, using devices to compensate angulations. Material and methods: Two implants were inserted into an aluminum base, and ball attachments were screwed to implants. Cylinders with O-rings were placed on ball attachments and connected to the test device using positioners to compensate implant angulations (0°, 7°, and 14°). Plexiglass bases were used to simulate implant angulations. The base and the test device were positioned in a testing apparatus, which simulated insertion/removal of an overdenture. A total of 2900 cycles, simulating 2 years of overdenture use, were performed and 36 O-rings were tested. The force required for each cycle was recorded with computer software. Longitudinal sections of ball attachment,positioner,cylinder with O-rings of each angulation were obtained to analyze the relationship among them, and O-ring sections tested in each angulation were compared with an unused counterpart. A mixed linear model was used to analyze the data, and the comparison was performed by orthogonal contrasts (,=0.05). Results: At 0°, the retention force decreased significantly over time, and the retention force was significantly different in all comparisons, except from 12 to 18 months. When the implants were positioned at 7°, the retention force was statistically different at 0 and 24 months. At 14°, significant differences were found from 6 and 12 to 24 months. Conclusions: Within the limitations of this study, it was concluded that O-rings for implant/attachments perpendicular to the occlusal plane were adequately retentive over the first year and that the retentive capacity of O-ring was affected by implant inclinations despite the proposed positioners. [source] The Hôtel de Bourgogne in 1760: Some Previously Unpublished Drawings by Louis-Alexandre GiraultJOURNAL FOR EIGHTEENTH-CENTURY STUDIES, Issue 4 2009JOHN GOLDER For Donald Roy and in memory of David Illingworth and Graham Barlow Abstract Built in 1548, the Hôtel de Bourgogne was in almost continuous use as a theatre for 235 years. We have, until now, had only an approximate idea of the internal layout of the auditorium and virtually no idea at all of the way in which the outbuildings were arranged. Recently, however, a series of architectural plans has come to light in the French National Archives. They date from 1760, which was when Papillon de La Ferté, who was in overall charge of the Royal Entertainments Department (les Menus-Plaisirs), ordered that the auditorium be both extensively refurbished and made more attractive, in order to increase audiences and to rescue the Italian players from a financially parlous position. Louis-Alexandre Girault, an architect attached to the Royal Entertainments, was put in charge of the work. The five plans and the longitudinal section which he has left us , and which are published and discussed here for the first time , allow us not only to visit the various different parts of the auditorium and stage, but also to have access to the public spaces, the actors' dressing rooms and their administrative offices, and even to go down into the store-rooms below the auditorium and the stage. [source] Obturator mononeuropathy caused by lipomatosis of the nerve: A case reportMUSCLE AND NERVE, Issue 2 2008Raffaele Nardone MD Abstract We report a patient who presented with the clinical features of obturator mononeuropathy. Abdomino-pelvic computed tomography revealed a fusiform mass in the right perivesical space; magnetic resonance imaging (MRI) showed characteristic "coaxial-cable-like" appearance in cross-section and "spaghetti-like" appearance in longitudinal section, pathognomonic of lipomatosis of the nerve. Nerve lipomatosis as the cause of obturator neuropathy has not been previously reported. MRI provides definite and graphic proof of the diagnosis. Muscle Nerve, 2008 [source] Side-to-side linking of myocardial cells in hypertrophic cardiomyopathy: Whole heart microscopic observation with tangential sectionsPATHOLOGY INTERNATIONAL, Issue 11 2005Hirotake Masuda By cross-section or longitudinal section, it is difficult to investigate longitudinal features of myocardial cells in the whole heart. Here, introducing the use of tangential sections to obtain longitudinal aspect of myocardial cells in any part of myocardium, the authors evaluated myocardium in the left ventricle in 10 normal hearts and four hearts with hypertrophic cardiomyopathy (HCM). Tangential sections were obtained by peeling the superficial layer of myocardium. After peeling the whole surface, secondary deep layer was peeled. These procedures were repeated more than five times through the wall. Intercalated discs (ICD) were observed immunohistochemically with anti-N-cadherin and antidesmoplakin. In normal hearts, myocardial cells were cut longitudinally and ran parallel in tangential sections. They linked end-to-end with simple and regular ICD with average lengths of 120,130 µm and average sarcomere numbers of 56,65. In HCM hearts, many myocardial cells were cut almost longitudinally running approximately parallel in tangential sections. Myocardial cells frequently showed side-to-side linking characterized by skewed ICD, indistinct ICD counterparts, and longitudinally arranged ICD. Two young HCM hearts had circle-shaped ICD and vacuole-like structures highlighted by immunostaining for N-cadherin, which were actually extracellular structures comparable with irregular side-to-side linking. It is considered that side-to-side linking of myocardial cells is a characteristic microscopic feature in HCM rather than myocardial disarray. [source] Systematic significance of fruit morphology and anatomy in tribes Persicarieae and Polygoneae (Polygonaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1-2 2000LOUIS P. RONSE DECRAENE FLS Fruits of Polygonaceae have a basically similar construction of indchiscent nuts or achencs. Sections of fruits, coupled with surface patterns were studied with SEM and LM in all genera of the tribes Persicarieae and Polygoneae (Polygonoidcae-Polvgonaceae). The outer layer of the pericarp is usually thickened and its anatomy can be used consistently to delimit genera more than any other character of the fruit. Cells are most often puzzle piece-shaped in surface view, but the shape of the cells may become polygonal with straight anticlinal walls towards the endocarp. The primary sculpture of the cells is highly yariable and has value at the specific level, rarely at the generic level. No strict correlation exists between the external surface patterns and the anatomy. Two main cell types can be recognized in cross- and longitudinal section, correlated with the straight or undulating outline of the anticlinal walls. No distinction can be made between sections Persicaria, Tovara, Echinocaulon, and Cephalophtlon of the genus Persicaria: all share narrow rectangular cells with undulating anticlinal walls. Aconogonon and Bistorta can be delimited by the square to rectangular cells with a narrow dichotomously branching lumen and straight anticlinal walls; both genera are best grouped as a single genus with two sections. A similar arrangement is found occasionally in species of Polygonum s.s. Polygonella. Atraphaxis. Faltopia and Calligonum. Fruit anatomy of Pteropyrum is distinctive. The genus Polygonum s.s. shows a wide range of integrating patterns, ranging from straight to undulating anticlinal walls and cannot be separated from Polygonella. Fagopyrum is aberrant in having a parenchymatic exocarp and a thickened mesocarp: other evidence supports its isolated position. Different fruit anatomical patterns have arisen several times in evolution and have a limited value at tribal level but are useful at generic level. It is suggested that an arrangement with straight anticlinal walls and a broad lumen, eventually with dendritic branching towards the periphery, is ancestral. [source] Comparison of bonding efficacy of an all-in-one adhesive with a self-etching primer systemEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2004Tomoko Abo The aim of this study was to compare the bonding efficacy of an all-in-one adhesive with that of a self-etching primer system by measuring microleakage after thermocycling and the microtensile bond strength (,TBS) to enamel and dentin. Circular class V cavities along cement,enamel junctions were prepared in 20 extracted human premolars. Each 10 teeth were bonded with either AD Bond (AD) or Clearfil SE Bond (SE), and filled with a resin composite (Charisma). After thermocycling and staining with 0.5% basic fuchsin, the microleakage at the coronal and apical walls was evaluated using longitudinal sections. In addition 20 premolars were used to measure ,TBS at 24 h after bonding for these adhesives to enamel and dentin that corresponded to the coronal and apical walls of the class V cavities. AD showed more microleakage than SE in the coronal walls, but there was less microleakage in the apical walls and no difference in apical leakage between the two adhesives. ,TBS (SD) in MPa to enamel and dentin were 25.2 (7.3) and 68.3 (9.4) for AD, and 35.8 (7.4) and 76.4 (7.8) for SE, respectively. AD gave a lower ,TBS to enamel than did SE. The results suggested that the poor adaptation at the coronal wall in AD might be caused by the lower bond strength to enamel. [source] A simple method for orienting silk and other flexible fibres in transmission electron microscopy specimensJOURNAL OF MICROSCOPY, Issue 3 2001J. E. Trancik When microstructures are characterized by transmission electron microscopy (TEM), the interpretation of results is facilitated if the material can be sectioned in defined orientations. In the case of fibres, it is especially useful if transverse and longitudinal sections can be obtained reliably. Here we describe a procedure for orienting spider silk and other flexible fibres for TEM investigation. Prior to embedding in epoxy resin, the silk is wound around a notched support made from polyester film. No glue is required. After the silk and its supporting film have been embedded and the resin has been cured the film can be peeled away to reveal nearly perfectly orientated silk threads. Both transverse and longitudinal sections can then be cut with a microtome. The method can be extended to obtain sections at any intermediate orientation. [source] Mechanical Behavior and Failure Analysis of Prosthetic Retaining Screws after Long-Term Use In Vivo.JOURNAL OF PROSTHODONTICS, Issue 3 2008Microhardness Analysis, Part 2: Metallurgical Abstract Purpose: This study involved testing and analyzing multiple retrieved prosthetic retaining screws after long-term use in vivo to: (1) detect manufacturing defects that could affect in-service behavior; (2) characterize the microstructure and alloy composition; and (3) further characterize the wear mechanism of the screw threads. Materials and Methods: Two new (control) screws from Nobel Biocare (NB) and 18 used (in service 18,120 months) retaining screws [12 from NB and 6 from Sterngold (SG)] were: (1) metallographically examined by light microscopy and scanning electron microscopy (SEM) to determine the microstructure; (2) analyzed by energy dispersive X-ray (EDX) microanalysis to determine the qualitative and semiquantitative average alloy and individual phase compositions; and (3) tested for Vickers microhardness. Results: Examination of polished longitudinal sections of the screws using light microscopy revealed a significant defect in only one Group 4 screw. No significant defects in any other screws were observed. The defect was considered a "seam" originating as a "hot tear" during original casting solidification of the alloy. Additionally, the examination of longitudinal sections of the screws revealed a uniform homogeneous microstructure in some groups, while in other groups the sections exhibited rows of second phase particles. The screws for some groups demonstrated severe deformation of the lower threads and the bottom part of the screw leading to the formation of crevices and grooves. Some NB screws were comprised of Au-based alloy with Pt, Cu, and Ag as alloy elements, while others (Groups 4 and 19) were Pd-based with Ga, Cu, and Au alloy elements. The microstructure was homogeneous with fine or equiaxed grains for all groups except Group 4, which appeared inhomogeneous with anomalous grains. SG screws demonstrated a typical dendritic structure and were Au-based alloy with Cu and Ag alloy elements. There were differences in the microhardness of gold alloy screws from NB and SG as well as palladium alloy screws from NB. Conclusions: Significant differences within NB retaining screws and between NB and SG screws were found for microstructure, major alloy constituents, and microhardness. [source] An improved sample preparation for an LC method used in the age estimation based on aspartic acid racemization from human dentinJOURNAL OF SEPARATION SCIENCE, JSS, Issue 1 2007Raja Yekkala Abstract The determination of age on the basis of aspartic acid (Asp) racemization in teeth is one of the most reliable and accurate methods to date. In this paper, the usefulness of HPLC coupled with fluorescence detection for determination of Asp racemization was evaluated. A modified sample preparation is proposed for better stability of o -phthaldialdehyde- N -acetyl- L -cysteine derivatives of D/L -Asp (due to the instability below pH 7). To ensure the accuracy of the method, the validation parameters' specificity, precision, linearity, and LOD were determined. Three dentin samples of premolar teeth, extracted from living individuals (bucco-lingual longitudinal sections of 1 mm thickness), were analyzed and quantitative results are discussed. [source] Sperm transfer during mating in the pharaoh's ant, Monomorium pharaonisPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2006D. ALLARD Abstract Sperm transfer in the pharaoh's ant Monomorium pharaonis (L.) is studied by making longitudinal sections through the gasters of mating pairs fixed in copula. Sperm is transferred inside a spermatophore similar to those found in two other ants, Diacamma sp. from Japan and Carebara vidua. Sharp teeth-ridges are present on the penis valves and, during copulation, these teeth make contact with a thick and soft cuticular layer covering the bursa copulatrix. This ensures an attachment long enough for the successful transfer of the spermatophore to the right position inside the female oviduct. The thick cuticle also protects the queen from serious damage by the male's sharp claspers. After a first successful copulation, sperm is still present inside the male's seminal vesicles, suggesting that males can mate multiply. Additional experiments, where single, initially virgin males are presented to several virgin females, confirm this. [source] Microleakage of composite resin restorations in cervical cavities prepared by Er,Cr:YSGG laser radiationAUSTRALIAN DENTAL JOURNAL, Issue 2 2008S Shahabi Abstract Background:, Evaluation of microleakage is important for assessing the success of new methods for surface preparation and new adhesive restorative materials. The aim of this laboratory study was to assess microleakage at the margins of composite restorations in Er,Cr:YSGG laser prepared cavities on the cervical aspects of teeth by means of dye penetration, and compare this with conventionally prepared and conditioned cavities. Methods:, Class V cavities were produced on sound extracted human teeth, which had been assigned randomly to one of three groups (N = 10 each), as follows: Group 1 , prepared using a diamond cylindrical bur and then treated with 37% phosphoric acid; Group 2 , irradiated with an Er,Cr:YSGG laser (Biolase Waterlase) and then treated with 37% phosphoric acid; Group 3 , irradiated only with the laser. After application of bonding agent (Excite, Ivoclar Vivadent), all cavities were restored with composite resin (Heliomolar). After polishing the restorations, the teeth were thermocycled from 5,50°C for 500 cycles. Dye leakage was assessed after immersion in methylene blue, by examining longitudinal sections in a stereomicroscope at ×30 magnification. Results:, The extent of dye penetration was lowest in the laser only group (Group 3). Penetration of dye to dentine and axial walls occurred in 80 per cent of conventionally prepared (bur + acid) specimens, but in the laser group, dye penetration to the axial wall occurred in only 30 per cent of cases. There was a strong statistical association between treatment group and the distribution of microleakage scores (Chi-square, P = 0.0023). Conclusions:, For Class V cavities, with the adhesive materials employed, higher microleakage occurs with phosphoric acid etching of bur- or laser-cut surfaces, than with the surface created by use of the laser alone without additional conditioning. [source] | |||||||||||||