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Internal Surface (internal + surface)
Terms modified by Internal Surface Selected AbstractsA Prospective Ten-Year Clinical Trial of Porcelain VeneersJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2006Article first published online: 25 APR 200 abstract Objective:, The purpose of this prospective clinical study was to evaluate the performance of porcelain veneers after 5 and 10 years of clinical service. Materials and Methods:, A single experienced clinician placed 87 porcelain veneers in 25 patients in 1990 and 1991. The teeth included maxillary central incisors to first premolars. As described in the 5-year report of this study, preparations included a chamfer margin, 0.3 to 0.7 mm labial enamel reduction, and incisal edge coverage. A single laboratory technician fabricated the veneers using feldspathic porcelain on refractory dies. Internal surfaces were etched with 5% hydrofluoric acid and silanated. Teeth were isolated with a rubber dam prior to veneer placement. All veneers were bonded with a light-activated resin cement. Patients were recalled at 5 to 6 years and at 10 years after initial veneer placement. Two evaluators examined each veneer for retention, fractures, color match, surface roughness, marginal adaptation, leakage, recurrent caries, pulp vitality, and patient satisfaction. Marginal adaptation was assessed further using scanning electron microscopy to examine epoxy replicas. Results:, Five years after placement, all 87 veneers remained in place and had "perfect" color match and surface smoothness. Four veneers had fractures, but only one of those required repair. Ninety-nine percent of the veneers had clinically acceptable marginal adaptation, although just 14% of the veneers had "perfect" marginal adaptation at all margins. One had clinically unacceptable staining from leakage. Recurrent caries was present at the proximal margin of two veneers. At the 10-year evaluation, which had a 93% recall rate, color match and surface roughness remained optimal. Thirteen of 22 patients were very satisfied with the esthetic result, whereas 7 complained of minor esthetic problems. The fracture rate increased substantially, to 34% at the 10-year recall. However, only 11% of the fractures were clinically unacceptable. None of the veneers had debonded, but the percentage of veneers with "perfect" marginal adaptation had declined to only 4%. Leakage was now evident around two-thirds of the veneers, and eight restorations had recurrent caries. Conclusion:, Porcelain veneers are a reliable and effective means for conservative esthetic treatment of anterior teeth in the long term. After 10 years of clinical service, esthetic results remained good, patient satisfaction was high, and the retention rate was excellent. The number of irreparable fractures was low. Appropriate preparation design, occlusion, and use of adhesive materials contribute to the ultimate outcome. [source] A Closer Look Inside Nanotubes: Pore Structure Evaluation of Anodized Alumina Templated Carbon Nanotube Membranes Through Adsorption and Permeability StudiesADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Georgios Pilatos Abstract Although hollow nanostructures, such as nanotubes, represent a major portion of nanoscaled materials with a tremendously large application range, a detailed evaluation of their internal characteristics still remains elusive. Transmission electron microscopy is the most common analytical technique to examine the internal configuration of these structures, yet it can only provide evidence of a minimal portion of the overall material, thus, it cannot be accurately generalized. In the present paper, in addition to electron microscopy and other spot-size analysis methods (X-ray diffraction, Raman spectroscopy, etc.), a combination of techniques including adsorption, permeability, and relative permeability are employed in order to provide important insights into various crucial details of the overall internal surface and hollow-space characteristics of carbon nanotube (CNT) arrays and membranes. The CNT arrays are fabricated using anodized alumina as a template in a flow-through chemical vapor deposition (CVD) reactor. This is the first systematic approach for investigating the internal configuration of template-based CNT arrays in detail. Key findings are made for the customized optimization of the resulting nanotube membranes for a variety of applications, including separations, nanofluidics and nanoreactors, biological capturing and purification, and controlled drug delivery and release. [source] Carbon Nanotube Coatings on Bioglass-Based Tissue Engineering ScaffoldsADVANCED FUNCTIONAL MATERIALS, Issue 15 2007R. Boccaccini Abstract The coating of highly porous Bioglass® based 3D scaffolds with multi-walled carbon nanotubes (CNT) was investigated. Foam like Bioglass® scaffolds were fabricated by the replica technique and electrophoretic deposition was used to deposit homogeneous layers of CNT throughout the scaffold pore structure. The optimal experimental conditions were determined to be: applied voltage 15,V and deposition time 20 minutes, utilizing a concentrated aqueous suspension of CNT with addition of a surfactant and iodine. The scaffold pore structure remained invariant after the CNT coating, as assessed by SEM. The incorporation of CNTs induced a nanostructured internal surface of the pores which is thought to be beneficial for osteoblast cell attachment and proliferation. Bioactivity of the scaffolds was assessed by immersion studies in simulated body fluid (SBF) for periods of up to 2 weeks and the subsequent determination of hydroxyapatite (HA) formation. The presence of CNTs can enhance the bioactive behaviour of the scaffolds since CNTs can serve as template for the ordered formation of a nanostructured HA layers, which does not occur on uncoated Bioglass® surfaces. [source] A Palladium Wall Coated Microcapillary Reactor for Use in Continuous Flow Transfer HydrogenationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Christian Abstract Herein we describe the preparation of a novel continuous flow multi-channel microreactor in which the internal surface has been functionalised with a palladium coating, enabling its use in catalytic heterogeneous liquid-phase reactions. Simple chemical deposition techniques were used to immobilise palladium(0) on the channel wall surface of a polymeric multi-capillary extrudate made from ethylene-vinyl alcohol copolymer. The Pd coating of the microcapillaries has been characterised by mass spectrometry and light and electron microscopy. The functional activity of the catalytic Pd layer was tested in a series of transfer hydrogenation reactions using triethylsilane as the hydrogen source. [source] A comparative study of mammalian tracheal mucous glandsJOURNAL OF ANATOMY, Issue 3 2000H. K. CHOI We have compared the distribution, numbers and volume of mucous glands in the tracheas of 11 mammalian species. No glands were present in the rabbit. The mouse only contained glands at the border between the trachea and larynx. In the rat, glands were commonest in the cephalad third of the trachea, but on average were much scarcer than in the larger species. Between species, there was a significant correlation between airway diameter and gland volume per unit surface area, suggesting that the rate of deposition of inhaled particles may increase in large airways. In the ventral portion of the trachea of about half the species, the glands were concentrated between the cartilaginous rings; in others they were evenly distributed over and between the rings. In most species in which the trachealis muscle attached to the internal surface of the cartilaginous rings, the glands were external to the muscle. In all species in which the muscle attached to the external surface of the cartilaginous rings, the glands were internal to the muscle. In the ox, goat, dog and sheep, the volume of glands per unit tracheal surface area was markedly greater in the ventral than the dorsal aspect of the trachea. The reverse was true of the pig. In humans, gland density in the 2 regions was similar. The frequency of gland openings was determined in the ox, goat, pig, dog and sheep tracheas, and ranged from 0.3 per mm2 in the dorsal portion of the sheep trachea to 1.5 per mm2 in the ventral portion of the ox trachea. For these 5 species, the volume of gland acini per unit luminal surface area varied linearly with the numbers of gland openings, with the volume of individual glands being constant at , 120 nl. [source] Small-angle neutron scattering investigation of plastically deformed stainless steelJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 3-1 2003Vassily Lebedev The microstuctural evolution of plastically deformed steels has been studied by small-angle neutron scattering at ambient temperature in the range of momentum transfer q = (4,/,)sin(,/2) = 0.01,5 nm,1 where , is neutron wavelength and , is the scattering angle. Samples of austenite stainless steels were pulled on a standard bench to cause a plastic deformation, S = 0,60%, up to the fracture of the material. As a result of the deformation an increase of an order of magnitude was observed in the scatterred intensity I(q)~1/[1+(qRC)2](6- Ds)/2. The analysis of the I(q) distribution has shown the surface fractal nature of the observed nano-scale structures. The evolution of internal surface via intensive growth of pores (size RC~20,40 nm) was found and a linear decrease of the surface fractal dimension 2.9,Ds(S),2.1 was observed. These findings can be used to design the fracture criteria for materials of industrial application. [source] A new nano-(2Li2O/MgO) catalyst/porous alpha-alumina composite for the oxidative coupling of methane reactionAICHE JOURNAL, Issue 3 2010Behrooz Fallah Abstract The present work discloses a new methodology for the production of detached nanorods of 2Li2O/MgO catalyst particles on the internal surface of ,-Al2O3 porous supports to be used as efficient catalysts for the oxidative coupling of methane reaction (OCM). The peculiarity of our preparatory recipe is the success in producing "detached" nanosized entities on the support surface. The performance of the new catalyst/support system for the OCM reaction has been evaluated using a special reactor assembly with cross flow of methane and oxygen gas streams. Under the optimum process conditions, the yield of C product is 25% at an average reaction temperature of 750°C. Under the optimum conditions, the yield of ethylene reaches 8%. It is shown that the enhanced catalytic properties of the new catalyst/support composite may be attributed to nanoeffects. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Metamorphosis of cinctoblastula larvae (Homoscleromorpha, porifera)JOURNAL OF MORPHOLOGY, Issue 6 2007Alexander V. Ereskovsky Abstract The metamorphosis of the cinctoblastula of Homoscleromorpha is studied in five species belonging to three genera. The different steps of metamorphosis are similar in all species. The metamorphosis occurs by the invagination and involution of either the anterior epithelium or the posterior epithelium of the larva. During metamorphosis, morphogenetic polymorphism was observed, which has an individual character and does not depend on either external or species specific factors. In the rhagon, the development of the aquiferous system occurs only by epithelial morphogenesis and subsequent differentiation of cells. Mesohylar cells derive from flagellated cells after ingression. The formation of pinacoderm and choanoderm occurs by the differentiation of the larval flagellated epithelium. This is possibly due to the conservation of cell junctions in the external surface of the larval flagellated cells and of the basement membrane in their internal surface. The main difference in homoscleromorph metamorphosis compared with Demospongiae is the persistence of the flagellated epithelium throughout this process and even in the adult since exo- and endopinacoderm remain flagellated. The antero-posterior axis of the larva corresponds to the baso-apical axis of the adult in Homoscleromorpha. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] Nerve conduits and growth factor delivery in peripheral nerve repairJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2007Lukas A. Pfister Abstract Peripheral nerves possess the capacity of self-regeneration after traumatic injury. Transected peripheral nerves can be bridged by direct surgical coaptation of the two nerve stumps or by interposing autografts or biological (veins) or synthetic nerve conduits (NC). NC are tubular structures that guide the regenerating axons to the distal nerve stump. Early synthetic NC have primarily been made of silicone because of the relative flexibility and biocompatibility of this material and because medical-grade silicone tubes were readily available in various dimensions. Nowadays, NC are preferably made of biodegradable materials such as collagen, aliphatic polyesters, or polyurethanes. Although NC assist in guiding regenerating nerves, satisfactory functional restoration of severed nerves may further require exogenous growth factors. Therefore, authors have proposed NC with integrated delivery systems for growth factors or growth factor,producing cells. This article reviews the most important designs of NC with integrated delivery systems for localized release of growth factors. The various systems discussed comprise NC with growth factors being released from various types of matrices, from transplanted cells (Schwann cells or mesenchymal stem cells), or through genetic modification of cells naturally present at the site of injured tissue. Acellular delivery systems for growth factors include the NC wall itself, biodegradable microspheres seeded onto the internal surface of the NC wall, or matrices that are filled into the lumen of the NC and immobilize the growth factors through physical-chemical interactions or specific ligand-receptor interactions. A very promising and elegant system appears to be longitudinally aligned fibers inserted in the lumen of a NC that deliver the growth factors and provide additional guidance for Schwann cells and axons. This review also attempts to appreciate the most promising approaches and emphasize the importance of growth factor delivery kinetics. [source] Physical properties of rocks from the upper part of the Yaxcopoil-1 drill hole, Chicxulub craterMETEORITICS & PLANETARY SCIENCE, Issue 6 2004Y. Popov Thermal conductivity, thermal diffusivity, density, and porosity were measured on 120 dry and water-saturated rocks with a core sampling interval of 2,2.5 m. Nondestructive, non-contact optical scanning technology was used for thermal property measurements including thermal anisotropy and inhomogeneity. Supplementary petrophysical properties (acoustic velocities, formation resisitivity factor, internal surface, and hydraulic permeability) were determined on a selected subgroup of representative samples to derive correlations with the densely measured parameters, establishing estimated depth logs to provide calibration values for the interpretation of geophysical data. Significant short- and long-scale variations of porosity (1,37%) turned out to be the dominant factor influencing thermal, acoustic, and hydraulic properties of this post impact limestone formation. Correspondingly, large variations of thermal conductivity, thermal diffusivity, acoustic velocities, and hydraulic permeability were found. These variations of physical properties allow us to subdivide the formation into several zones. A combination of experimental data on thermal conductivity for dry and water-saturated rocks and a theoretical model of effective thermal conductivity for heterogeneous media have been used to calculate thermal conductivity of mineral skeleton and pore aspect ratio for every core under study. The results on thermal parameters are the necessary basis for the determination of heat flow density, demonstrating the necessity of dense sampling in the case of inhomogeneous rock formations. [source] Enhanced control of porous silicon morphology from macropore to mesopore formationPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2005Huimin Ouyang Abstract Porous silicon (PSi) is a versatile material that possesses a wide range of morphologies. There are two main types of microstructures that are widely used and well studied: branchy mesoporous silicon with pore sizes from 10 nm to 50 nm and classical macroporous silicon with pore sizes from 500 nm to 20 µm. Much less work has been done on structures with intermediate pore sizes from 100 nm to 300 nm. Applications such as immunoassays biosensing can greatly benefit from the intermediate morphology due to the larger pore openings compared to mesopores, and increased internal surface compared to classical macropores. In this work we demonstrate well-defined macropore of 150 nm diameter in average and precise control of the porous silicon morphology transition from smooth macropores to branchy mesopores on one substrate with one electrolyte. A multilayer structure (microcavity) consisting of both mesopores and macropores is presented. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Gravimetric method to find internal surface of macroporous silicon membranesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2007A. A. Nechitailov Abstract A simple method to evaluate the internal surface area, porosity, pore diameter and pore density of macroporous silicon membranes has been proposed and tested. The porosity p is obtained from the mass loss under anodizing, and the surface area per unit volume Sv is determined from the mass of SiO2 formed on the pore surface as a result of thermal oxidation. The average pore diameter d and pore density N can be easily calculated from the obtained Sv and p. Experimental verification of d and N was performed by means of SEM and optical microscope images; Sv was checked by BET technique. Surface area and porosity on the resistivity of initial n-Si in the range , = 3,25 Ohm · cm have been studied for the samples with regular and self-organized macropore "lattices". The obtained values are within the limits p = 27,50%, Sv = 2800,6000 cm2/cm3, d = 1.9,6.5 ,m, N = 1.4,10 × 106 cm,2, and in a good agreement with the data of microscopic characterization. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Brief communication: Histology and micro CT as methods for assessment of facial suture patencyAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Lauren E. Reinholt Abstract The extent of fusion in facial sutures has implications for topics ranging from biomechanics to phylogeny reconstruction. An unfortunate limitation of studying sutural fusion in skeletal specimens is that it is difficult to assess whether apparently patent sutures are in fact fused internally. Both histology and microcomputed tomography (CT) are potential tools for solving this, but relatively few studies have attempted to discern the limits of micro CT for visualization of microanatomical structures. We examined microanatomical aspects of facial sutures in adult cadaveric samples from captive bushbabies. Premaxillary and nasopremaxillary sutures were examined in serially sectioned snouts of four greater bushbabies (Otolemur garnettii) and four lesser bushbabies (Galago moholi). Sections containing sutures with osseous bridging were rated as "fused," and the presence or absence of grooves on the external side was recorded. One bushbaby was studied using micro CT prior to physical sectioning. O. garnettii and two of the G. moholi show multiple foci of fusion. Histological examination confirmed that sutural fusion is limited to the internal surface in numerous sections, resulting in an external notch. Such points of internal fusion could be clearly visualized in raw CT slices. The presence of such notches suggests that external examination can underestimate the degree of suture fusion. Thus, microanatomical evidence may be needed to fully assess biomechanical correlates and phylogenetic interpretations based on fusion of facial sutures. Our results also indicate micro CT may be a useful tool to obtain this evidence. Am J Phys Anthropol 2009. © 2009 Wiley-Liss, Inc. [source] Novel mechanism of blocking axonal Na+ channels by three macrocyclic polyamine analogues and two spider toxinsBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2001Masuhide Yakehiro The mechanism of Na+ channel block by three macrocyclic polyamine derivatives and two spider toxins was studied with voltage clamp and internal perfusion method in squid axons. All these chemicals specifically block Na+ channels in the open state only from the internal surface, and do not affect K+ channels. The blocking effect is enhanced as the depolarizing pulse becomes larger. Blocked channels are unable to shift to the inactivated state. In the case of cyclam and guanidyl-side armed cyclam (G-cyclam), quick release of these chemicals from the binding sites is proven by the increase in the tail current and prolongation of the time course of the off gating current. On the other hand, in the presence of N-4 and the spider toxins, their detachment was delayed significantly. Molecular requirements for the block of Na+ channels by these molecules are the presence of positive charge and hydrophobicity. British Journal of Pharmacology (2001) 132, 63,72; doi:10.1038/sj.bjp.0703765 [source] Nanoporous Composites: A Three-Dimensional Gold-Decorated Nanoporous Copper Core,Shell Composite for Electrocatalysis and Nonenzymatic Biosensing (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 14 2010Mater. M. W. Chen and co-workers present a novel gold-decorated nanoporous copper (Au@NPC) core,shell composite on page 2279. Thin gold shells with controllable thickness are homogeneously deposited onto the internal surfaces of 3D NPC via a spontaneous displacement reaction while NPC is utilized as a reduction agent as well as template and substrate. The inexpensive core shell nanostructure exhibits significant electrocatalytic activity for oxidation methanol and high nonenzymatic sensitivity in detecting glucose. [source] A Three-Dimensional Gold-Decorated Nanoporous Copper Core,Shell Composite for Electrocatalysis and Nonenzymatic BiosensingADVANCED FUNCTIONAL MATERIALS, Issue 14 2010L.Y. Chen Abstract Bimetallic core,shell nanostructures have attracted increasing attention due to their low material costs along with enhanced chemico-physical properties in comparison with their monometallic counterparts. Here, a novel gold-decorated nanoporous copper (Au@NPC) core,shell composite fabricated by a facile in situ hydrometallurgy approach is reported. Thin gold shells with a controllable thickness are homogeneously deposited onto the internal surfaces of 3D nanoporous copper via a spontaneous displacement reaction while nanoporous copper is utilized as a reduction agent as well as 3D template and substrate. The resulting inexpensive core,shell nanostructure exhibits significant electrocatalytic activity for the oxidation of methanol and high non-enzymatic sensitivity in detecting glucose. [source] Microplane constitutive model for porous isotropic rocksINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 1 2003k P. Ba Abstract The paper deals with constitutive modelling of contiguous rock located between rock joints. A fully explicit kinematically constrained microplane-type constitutive model for hardening and softening non-linear triaxial behaviour of isotropic porous rock is developed. The microplane framework, in which the constitutive relation is expressed in terms of stress and strain vectors rather than tensors, makes it possible to model various microstructural physical mechanisms associated with oriented internal surfaces, such as cracking, slip, friction and splitting of a particular orientation. Formulation of the constitutive relation is facilitated by the fact that it is decoupled from the tensorial invariance restrictions, which are satisfied automatically. In its basic features, the present model is similar to the recently developed microplane model M4 for concrete, but there are significant improvements and modifications. They include a realistic simulation of (1) the effects of pore collapse on the volume changes during triaxial loading and on the reduction of frictional strength, (2) recovery of frictional strength during shearing, and (3) the shear-enhanced compaction in triaxial tests, manifested by a deviation from the hydrostatic stress,strain curve. The model is calibrated by optimal fitting of extensive triaxial test data for Salem limestone, and good fits are demonstrated. Although these data do not cover the entire range of behaviour, credence in broad capabilities of the model is lend by its similarity to model M4 for concrete,an artificial rock. The model is intended for large explicit finite-element programs. Copyright © 2002 John Wiley & Sons, Ltd. [source] Microfluidic Valves Comprising Nanolayered Thermoresponsive Polymer-Grafted Capillaries,ADVANCED MATERIALS, Issue 22 2005N. Idota Thermally regulated flow control using a thermoresponsive polymer grafted onto surfaces of capillary lumen facilitates rapid, reliable, and repeatable open,close cycles (see Figure). Hydration of the grafted polymer chains on the internal surfaces may increase the microviscosity of the hydration layers at the wall interfaces without physically occluding the lumen, producing complete and reversible on/off flow valving in microchannels under hydrostatic pressures relevant for microfluidics approaches. [source] Nurse-led flexible cystoscopy: the UK experience informs a New Zealand nurse specialist's trainingINTERNATIONAL JOURNAL OF UROLOGICAL NURSING, Issue 2 2007Sue Osborne Abstract Flexible cystoscopy utilizes a fibre-optic scope with a light source to examine the internal surfaces of the bladder and urethra. The procedure is undertaken to investigate and diagnose the cause of lower urinary tract symptoms. It is also used extensively to detect the recurrence of bladder tumours in people diagnosed with transitional cell carcinoma of the bladder and kidney. In the UK, the advent of flexible cystoscopy clinics undertaken by appropriately trained and supervised nurses has been one way of improving provision of a flexible cystoscopy service. Information from published literature informed the decision to establish a nurse-led flexible cystoscopy clinic at one large District Health Board in New Zealand. This article reviews the current body of knowledge on nurse-led flexible cystoscopy, focusing on the education and training required to prepare nurses for independent cystoscopy practice. Literature findings are discussed, along with the observations of a urology nurse specialist undertaking flexible cystoscopy training in New Zealand and anecdotal evidence from visits with nurse cystoscopists in England during 2006. Carefully designed research studies published in literature have a key role to play in augmenting the body of evidence around this relatively new area of nursing practice, and as such should be strongly encouraged in both countries. It is recommended that nurse cystoscopy training and competencies are standardized and adopted internationally in order to increase the transferability of findings from research on the clinical outcomes of nurses performing nurse-led flexible cystoscopy. [source] Band-related leg injuries in an Australian passerine and their possible causesJOURNAL OF FIELD ORNITHOLOGY, Issue 2 2006Kate Splittgerber ABSTRACT We examined the extent and causes of band-related leg injuries in an Australian passerine, the Bell Miner (Manorina melanophrys). Eight percent of banded birds exhibited leg injuries, and most were birds with two plastic color bands on a tarsus. Leg injuries typically followed the accumulation of shed tarsal scales under the color bands. Color bands used on Bell Miners were tighter on the tarsus than the metal band and also tighter than the color bands used on Superb Fairy-wrens (Malurus cyaneus), a commonly banded species with no reported leg injuries. The tendency for scales to accumulate under two plastic color bands appeared to be influenced by the diameter of a band relative to the size of a bird's tarsus (with looser bands less likely to cause accumulation) and the material used to make the band (with smoother surfaces less likely to cause accumulation). Celluloid color bands had rougher internal surfaces than either Darvic or metal bands. In addition, both celluloid and Darvic color bands generated static electricity capable of attracting tarsal scales. Scales that accumulated under bands provided an environment where potentially harmful fungi became established, potentially contributing to the severity of leg injuries. Our results suggest that, when selecting an appropriate band size for a bird, the diameter of the tarsus at its midpoint should occupy only between 60% and 65% of the internal diameter of the band and, when possible, a single, bicolored, anodized aluminum alloy band should be used instead of multiple plastic color bands. SINOPSIS Examinamos la causa y la extensión de lesiones en las patas causadas por anillas en Manorina melanophrys, en Australia. Un 8% de las aves mostraron lesiones en las patas, la mayoría aves con dos anillas plásticas. Las lesiones causaron la acumulación de escamas tarsales mudadas, bajo la anilla. Se encontraron que las anillas plásticas ejercían mas presión o estaban más ajustadas que las anillas de metal y que estaban más apretadas que en Malurus cyaneus, una especie comúnmente anillada y en donde no encontramos lesiones. La tendencia de acumulación de escamas bajo las dos anillas plásticas, parece ser influenciada por el diámetro de la anilla, con respecto al grosor del tarso del ave y del material con que estuvo echo la anilla. Encontramos que las anillas de celuloide tienen una superficie interna más áspera que las anillas de metal. Además, ambos tipos de anillas, generan estática capaz de atraer las escama de la pata. Las partículas de escama que se acumulan bajo una anilla proveen de una buena base para que se crezcan hongos, que contribuyen a la gravedad de la lesión en la pata. Sugerimos que se deben seleccionar anillas apropiadas en tamaño en donde el diámetro del tarso en la parte media de la pata, ocupe entre el 60,65% del diámetro interno de la anilla. También, que cuando sea posible, se utilice una sola anilla de metal pintada con dos colores, en vez de dos anillas plásticas. [source] Influence of repeated screw tightening on bacterial leakage along the implant,abutment interfaceCLINICAL ORAL IMPLANTS RESEARCH, Issue 12 2009Cássio Do Nascimento Abstract Objectives: Bacterial penetration along the implant,abutment interface as a consequence of abutment screw loosening has been reported in a number of recent studies. The aim of this in vitro study was to investigate the influence of repeated tightening of the abutment screw on leakage of Streptococcus mutans along the interface between implants and pre-machined abutments. Materials and methods: Twenty pre-machined abutments with a plastic sleeve were used. The abutment screws were tightened to 32 N cm in group 1 (n=10 , control) and to 32 N cm, loosened and re-tightened with the same torque twice in group 2 (n=10). The assemblies were completely immersed in 5 ml of Tryptic Soy Broth medium inoculated with S. mutans and incubated for 14 days. After this period, contamination of the implant internal threaded chamber was evaluated using the DNA Checkerboard method. Results: Microorganisms were found on the internal surfaces of both groups evaluated. However, bacterial counts in group 2 were significantly higher than that in the control group (P<0.05). Conclusion: These results suggest that bacterial leakage between implants and abutments occurs even under unloaded conditions and at a higher intensity when the abutment screw is tightened and loosened repeatedly. [source] | ||||||||||||||||||||||