88 research outputs found
Comparative evaluation of the regional micro-push-out bond strength of custom-made resin post system with a prefabricated resin post: An in vitro study
No full textAim : The purpose of the study is to compare the regional micro-push-out bond strength of custom-made resin post and a prefabricated resin post luted using self-etch adhesive and/or etch and rinse adhesive system at various regions.
Materials and Methods : Forty freshly extracted human maxillary central incisors were selected for this study; 1.5-2-mm coronal to the cemento-enamel junction was removed with a diamond disk using a slow speed handpiece under cooling water. Working lengths were established, root canals were sequentially enlarged upto the apex until ISO size 50-K-file and obturated using gutta-percha and AH plus sealer by cold lateral compaction. Post spaces were prepared to a depth of 10 mm using paeso-reamer upto size #3. After preparation, each specimen was embedded in chemically cured acrylic resin. The roots were randomly assigned to four groups: Group I: Custom-made resin post+Self-etch adhesive, Group II: Glass FRC post+Self-etch adhesive, Group III: Custom-made resin post+Etch and Rinse adhesive, Group IV: Glass FRC post+Etch and Rinse adhesive. Fabrication of custom-made resin post was done. All the posts were cemented using a dual cure resin luting cement. Each root was sectioned perpendicular to the long axis using a microtome and subjected to micro-push-out bond strength.
Results: The micro-push-out bond strength in the coronal region, in Group I 13.5±1.66 MPa, Group II 12.08±0.8 MPa, Group III 11.15±1.06 MPa, Group IV 11.81±1.11 MPa. In the middle third region: Group I 11.43±0.740 MPa, Group II 10.584±0.504 MPa, Group III 10.0582±0.830 MPa, Group IV 10.35±0772 MPa. In the apical third: Group I 10.38±0.878 MPa, Group II 9.59±1.06 MPa, Group III 9.34±0.73o MPa, Group IV 8.77±1.02 MPa.
Conclusion : Within the limitations of the study, amongst all the four groups tested, custom-made resin post luted with self-etch system (CMPR-SE) showed higher micro-push-out bond strength values in all regions when compared to the other group
Development of a 100 mm-Diameter Split-Hopkinson Pressure Bar for High Strain Rate Characterization of Concrete
No full textThe Split-Hopkinson Pressure Bar (SHPB) is an experimental technique used to examine the behavior of materials at high strain rates. The aim of this paper is to present the development of a SHPB for the testing of concrete at high strain rates. The construction of the SHPB is detailed, including the important decisions made during its development. The basic calibration of the setup has been performed. The ordinary and fiber reinforced concrete (FRC) specimens (M30) with a diameter of 100 mm and L/D ratio of 0.5 are tested at a strain rate of about 50 to 65 s−1. The comparison of the results from the SHPB test and the quasi-static test is also presented. From the results, it is concluded that the developed SHPB is giving consistent results for the ordinary concrete, whereas for FRC specimens, there is a difference in the peak stress, which could be the variabilities in the dispersion of fibers in the concrete. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd
The Anatomy of Pelvic Corona Mortis Vessels in South Indian Population: A Cadaveric study
No full textApplications of self-assembling peptide scaffolds in regenerative medicine: the way to the clinic
No full textPeptides that self-assemble into well-defined nanofibrous networks provide a prominent alternative to traditional biomaterials for fabricating scaffolds for use in regenerative medicine and other biomedical applications. Such scaffolds can be generated by decorating a peptide backbone with other bioactives such as cell specific adhesion peptides, growth factors and enzyme cleavable sequences. They can be designed to mimic the three-dimensional (3D) structural features of native ECM and can therefore also provide insight into the ECM-cell interactions needed for development of scaffolds that can serve as regeneration templates for specific target tissues or organs. This review highlights the potential application of self-assembling peptides in regenerative medicine.Funding Agencies|Swedish Research Council, Sweden [2012-42315-94008-81]</p
Crystal structures of 6a,6b,7,11a-tetrahydro-6H,9H-spiro[chromeno[3′,4′:3,4]pyrrolo[1,2-c]thiazole-11,3′-indoline]-2′,6-dione and 5′-methyl-6a,6b,7,11a-tetrahydro-6H,9H-spiro[chromeno[3′,4′:3,4]pyrrolo[1,2-c]thiazole-11,3′-indoline]-2′,6-dione
No full textThe title compounds, C20H16N2O3S, (I), and C21H18N2O3S, (II), differ by the presence of a methyl group in position 5 on the 1H-indole-2-one ring of compound (II). The two compounds have a structural overlap r.m.s. deviation of 0.48 Å. There is a significant difference in the conformation of the thiazolidine ring: it has a twisted conformation on the fused N—C bond in (I), but an envelope conformation in compound (II) with the S atom as the flap. The planar pyrrolidine ring of the indole ring system is normal to the mean plane of the five-membered pyrrolidine ring of the pyrrolothiazole unit in both compounds, with dihedral angles of 88.71 (9) and 84.59 (8)°. The pyran rings in both structures have envelope conformations with the methylene C atom adjacent to the C=O group as the flap. In both compounds, there is a short intramolecular C—H...O contact present. In the crystal of (I), molecules are linked by C—H...O hydrogen bonds forming chains propagating along the b-axis direction. The chains are linked by N—H...π interactions, forming layers parallel to (10\overline{1}). In the crystal of (II), molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers which are linked by C—H...O hydrogen bonds to form a three-dimensional structure
Synthesis of magnetic activated carbon/α-Fe2O3 nanocomposite and its application in the removal of acid yellow 17 dye from water
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Reflectance spectroscopy and analytical techniques in characterising PGE-bearing host rocks
No full textThe Mettuppalaiyam mafic and ultramafic complex (MUC) is part of the Southern Granulite terrain in India. MUC is one of the promising sites for Ni-Cu-Cr and Platinum Group of Elements (PGE) mineralisation. The Geological Survey of India (GSI) has conducted geological and geochemical studies at the Mettuppalaiyam complex in different periods to assess PGE concentration in the mafic and ultramafic rocks. Mafic-ultramafic rock samples from the Solavanur, Mallanayakkanpalaiyam and Karappadi blocks of the Mettuppalaiyam complex were used in the present study to acquire reflectance spectroscopic measurements. Twenty-three rock samples with mafic, ultramafic and intermediate compositions were collected. The reflectance spectra were obtained under 350 nm-2500 nm spectral range using ASD FieldSpec Pro® spectroradiometer. The continuum-removed reflectance spectra provide diagnostic absorption features for various host rocks. The influence of elemental composition and associated key minerals in the rock samples on absorption bands was critically analysed.The XRF method was adopted to analyse the chemistry of host rocks. The XRD analysis was carried out from selected rock samples to assess the dominant and key minerals in the host rocks. The XRD and XRF analysis results correlated with the absorption features. The absorption features in the UV–visible spectrum are mainly due to the electronic process of transition metal ions and charge transfer of metals. The overtones and vibration spectra of Al-OH, Fe-OH, Mg-OH and carbonate ions in the rock samples influence the absorption bands in the SWIR region. The absorption bands are due to key minerals like clinochlore/chlorite, actinolite, antigorite and amphiboles. The ore microscopic study, HR-ICPMS and SEM EDAX analyses show encouraging results of PGE concentration in host rocks and validated the spectral results
Influence of Metal (Aluminium) Layer Thickness in Glare
No full textABSTRACT: The ductile resistance of the fibre-metal laminates has been analysed experimentally on three various different FML laminates that is made up of aluminium sheets of three different thickness namely 0.2mm, 0.3mm & 0.4mm. Tensile and flexural tests on the specimens were carried out to analyse the ductile behaviour of the FML laminates. Stress vs strain curve for tensile and load vs displacement curve for flexural test. The respective parameters like ultimate stress, young's modulus, longitudinal strength, flexural failure, flexural modulus, etc., are calculated from the plots. The results were compared with each other to evaluate what is the impact of metal layer thickness in the FML plates. There is good variation between the experimental results is obtained. Finally the best fiber to metal ratio is found out and the result is justified
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