A novel tight cylindrical mold for epoxy resin embedding allows enhanced microscopic analysis of microcores extracted from woody plants

The aim of this laboratory study was to compare the interfacial adaptation of an epoxy-resin and a self-etch sealer in mesial root canals of mandibular molars filled using the System-B/Elements Obturation Unit. Sixty mesial root canals of mandibular molars were prepared using the K3 rotary system up to 35.04 instrument and then filled with the aid of the System-B/Elements Obturation Unit using either gutta-percha/ThermaSeal Plus (n=15) or Resilon/Real Seal SE (n=15). The single cone technique using both materials was used as control. The sealers were stained with Rhodamine B dye and the teeth were filled and sectioned at 2, 4 and 6 mm from the apex. The interfacial marginal adaptation of sealers was evaluated using confocal microscopy. Statistical analyses were performed by the Kruskall-Wallis test (α=0.05). In general, microscopic analysis showed a quite regular gap distribution pattern at sealer-dentin interfaces, mainly for the two groups filled with Real Seal SE. This means that both nonbonding root-filling groups (ThermaSeal Plus) showed significantly higher amount of gap-free regions regardless of the filling technique (p<0.05). Better marginal adaptation was obtained with gutta-percha and epoxy resin-based sealer using either the system B or the single cone technique.

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THE FRAGMENTATION OF THE TENSIONED ZONE OF THE STRENGTHENED REINFORCED CONCRETE BEAM WITH CARBON FIBER COMPOSITE

Engineering Structures and Technologies ◽

10.3846/skt.2010.17 ◽

2010 ◽

Vol 2 (4) ◽

pp. 129-137 ◽

Cited By ~ 2

Author(s):

Gediminas Marčiukaitis ◽

Mykolas Daugevičius ◽

Juozas Valivonis

Keyword(s):

Reinforced Concrete ◽

Carbon Fiber ◽

Epoxy Resin ◽

Fiber Composite ◽

Composite Layer ◽

Microscopic Analysis ◽

Reinforced Concrete Beam ◽

Carbon Fiber Composite ◽

Composite Joint ◽

Concrete Layer

The article analyzes the intensification influence of tensioned concrete on carbon fiber composite and concrete joint in a strengthened beam cracking manner. The paper calculates enlarged concrete compressive tensioned strength according to the impregnation of epoxy resin. The article figures out the level of epoxy resin penetration and deals with a microscopic analysis of concrete and carbon fiber composite joint. The presented modified calculation method of the cracking moment evaluates the characteristics of impregnated modified tensioned concrete. Four beams were tested. Two reinforced concrete beams were additionally strengthened with an external carbon fiber composite layer and loaded till failure. In addition, two reinforced beams without external reinforcement were tested. The accomplished experimental research of cracking strengthened beams showed that the calculated cracking moments with evaluated tensioned concrete layer intensification were more similar than the results without evaluation. After failure of strengthened beams, accomplished microscopic analysisof debonded carbon fiber composite layer. A microscopic analysis of concrete and carbon fiber composite joint was performed applying electronic microscope DG-3x. The thickness of the composite layer and modified tensioned concrete layer was measured using Micro Measure V 1.0 computer program. The accomplished microscopic analysis approved theoretical assumptions about epoxy resin penetration and distribution between aggregates. The strengthening of the reinforced concrete beam with carbon fiber composite improved mechanical characteristics of the tensioned concrete layer near concrete and carbon fiber composite joint. During strengthening, epoxy resin penetrates into concrete and fills micro cracks and pores. Thus, epoxy resin provides additional connections with aggregates. The calculated modified concrete tensioned strength and modulus of elasticity was respectively 3,0 and 1,9 times higher than that of ordinary concrete. Changes in concrete strength at the tensioned layer have influence on cracking manner because the ultimate deformation of modified concrete increases. Experimentally determined what evolution of vertical crack starts above the modified tensioned concrete layer at the joint with carbon fiber composite. Peeling the carbon fiber composite layer when the ultimate load level is reached also evolves above the modified tensioned concrete layer. The remained hydrated cement on the surface of the peeled external composite layer proves that shear stresses in the joint of concrete and carbon fiber composite reduced a weaker tensioned layer of concrete.

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Investigation and Evaluation of the Emulsified Asphalt with Waterborne Epoxy Resin

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.842.337 ◽

2020 ◽

Vol 842 ◽

pp. 337-345

Author(s):

Yan Jun Zhang ◽

Wen Ming Wu ◽

Hai Sheng Cao ◽

Li Dong Zhao ◽

Yong Li Zhang ◽

...

Keyword(s):

High Temperature ◽

Epoxy Resin ◽

Asphalt Mixture ◽

Microscopic Analysis ◽

Splitting Strength ◽

Waterborne Epoxy ◽

Bonding Properties ◽

Road Performance ◽

Waterborne Epoxy Resin ◽

Emulsified Asphalt

Compared with SBR latex, waterborne epoxy resin has obvious advantages. The cured epoxy resin emulsified asphalt material has stronger mechanical properties, but it is less used in asphalt modification applications. Aiming at this problem, this paper uses waterborne epoxy resin as the modified material of emulsified asphalt, and carries out performance characterization and road performance evaluation of waterborne epoxy resin modified emulsified asphalt and its mixture under different dosages. Fluorescence microscopic analysis of waterborne epoxy asphalt with a content of 8wt%, 15wt%, 30wt%, and 50wt%, respectively, shows that the resin content should not exceed 30wt% to ensure the performance of asphalt. The bonding properties of SBR modified emulsified asphalt and waterborne epoxy resin modified emulsified asphalt with different dosages at 20 °C and 60 °C were analyzed. The results show that the tensile strength and oblique shear of waterborne epoxy modified emulsified asphalt. The strength is higher than SBR modified emulsified asphalt, and its high temperature resistance is better than SBR modified emulsified asphalt material. The road performance analysis was carried out on the mixture prepared by the aqueous epoxy modified emulsified asphalt with the content of 0wt%, 8wt%, 15wt% and 30wt% respectively. The results show that with the increase of waterborne epoxy content, the Marshall stability, splitting strength and high temperature rutting resistance of the mixture increase more obviously. The freeze-thaw splitting strength of the waterborne epoxy resin mixture is 13% higher than that of the pure emulsified asphalt mixture, and the splitting strength is also significantly improved. Due to the high stiffness of the waterborne epoxy resin after curing, the maximum bending strain of the mixture is reduced, and the recommended dosage is not more than 30% by weight. On the whole, the introduction of waterborne epoxy resin could greatly improve the strength and road performance of the asphalt, and could be used as a proper road repair material.

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Preparatory Procedures for Electron Microscopic Analysis at the Molecular Level of Resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070230 ◽

1978 ◽

Vol 36 (3) ◽

pp. 516-520

Author(s):

F.J. Sjostrand

Keyword(s):

Electron Microscope ◽

Molecular Level ◽

Microscopic Analysis ◽

Resolving Power ◽

Cellular Structures ◽

Electron Microscopic ◽

Systematic Analysis ◽

Technical Developments ◽

Thin Sectioning ◽

Obvious Reason

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.

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Ultrastructural investigation of spontaneous pituitary gonadotroph cell adenomas in aging Sprague-Dawley rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077086 ◽

1983 ◽

Vol 41 ◽

pp. 702-703

Author(s):

D. J. McComb ◽

J. Beri ◽

F. Zak ◽

K. Kovacs

Keyword(s):

Electron Microscopy ◽

Animal Model ◽

Epoxy Resin ◽

Immunoelectron Microscopy ◽

Tumor Type ◽

Gonadal Function ◽

Sprague Dawley ◽

Male And Female ◽

Reticulin Fibers ◽

Sprague Dawley Rats

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.

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Surface Structure in Microtomed Sections Caused by Glass and Diamond Knives

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066334 ◽

1971 ◽

Vol 29 ◽

pp. 456-457

Author(s):

J. Temple Black ◽

William G. Boldosser

Keyword(s):

Plastic Deformation ◽

Epoxy Resin ◽

Carbon Coating ◽

Surface Damage ◽

Body Angle ◽

Normal Manner ◽

Bottom Side ◽

Cutting Direction ◽

Made In ◽

Diamond Knife

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.

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Epoxy Resin Embedment

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010024x ◽

1968 ◽

Vol 26 ◽

pp. 100-101

Author(s):

J. G. Adams ◽

M. M. Campbell ◽

H. Thomas ◽

J. J. Ghldonl

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Epoxy Resin ◽

Light Microscope ◽

Epoxy Resins ◽

Image Contrast ◽

Tissue Preservation ◽

Resin System ◽

Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

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The Application of Ultra-Thin Sectioning Techniques to Non-Biological Samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101402 ◽

1968 ◽

Vol 26 ◽

pp. 332-333

Author(s):

C. F. Oster

Keyword(s):

Biological Sciences ◽

Epoxy Resin ◽

Cross Sections ◽

Biological Samples ◽

Industrial Applications ◽

Photographic Film ◽

Silver Particles ◽

Thin Sectioning ◽

Embedding Medium

Although ultra-thin sectioning techniques are widely used in the biological sciences, their applications are somewhat less popular but very useful in industrial applications. This presentation will review several specific applications where ultra-thin sectioning techniques have proven invaluable.The preparation of samples for sectioning usually involves embedding in an epoxy resin. Araldite 6005 Resin and Hardener are mixed so that the hardness of the embedding medium matches that of the sample to reduce any distortion of the sample during the sectioning process. No dehydration series are needed to prepare our usual samples for embedding, but some types require hardening and staining steps. The embedded samples are sectioned with either a prototype of a Porter-Blum Microtome or an LKB Ultrotome III. Both instruments are equipped with diamond knives.In the study of photographic film, the distribution of the developed silver particles through the layer is important to the image tone and/or scattering power. Also, the morphology of the developed silver is an important factor, and cross sections will show this structure.

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