Search results for "Material testing"

showing 3 items of 3 documents

Influence of chitin nanocrystals on the dielectric behaviour and conductivity of chitosan-based bionanocomposites

2018

[EN] A series of bionanocomposite films based on chitosan, reinforced with chitin nanocrystals, were developed, and assessed in terms of dielectric behaviour and conductivity by using an experimental methodology that allows avoiding the conductivity contribution and the exclusion of contact and interfacial polarization effects. The dielectric relaxations at low and high frequency and temperatures were modeled by Havriliak-Negami functions. Below the glass transition temperature (Tg), the gamma and beta relaxations were observed, which were related to intramolecular and non-cooperative segmental movements. At higher temperatures, an intermolecular and cooperative macromolecular movement, rel…

BionanocompositesSolucions polimèriquesMaterials scienceMaterial testingIonic bonding02 engineering and technologyDielectricActivation energyConductivity010402 general chemistry01 natural sciencesChitosanchemistry.chemical_compoundElectrical resistivity and conductivity[CHIM.ANAL]Chemical Sciences/Analytical chemistryComposite materialsChitosanChitosanIntermolecular forceGeneral EngineeringINGENIERIA DE LOS PROCESOS DE FABRICACION[CHIM.MATE]Chemical Sciences/Material chemistryCiència dels materials021001 nanoscience & nanotechnology0104 chemical sciencesChitin nanocrystals[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry[CHIM.POLY]Chemical Sciences/PolymersChemical engineeringchemistryMAQUINAS Y MOTORES TERMICOSCeramics and CompositesChitin nanocrystal0210 nano-technologyGlass transitionDielectric thermal analysis (DETA)
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Citotoxicity of four types of resins used for removable denture bases: in vitro comparative analysis

2009

Objective: To compare the cytotoxicity of four types of resins used for manufacturing denture bases. Method and Materials: 9 disk-shaped samples of four resin (two heat-polymerized, one auto-polymerized, and one light-polymerized), 9 samples of glass (negative control) and 9 samples of lead (positive control) were made according to the manufacturer instructions. The materials were tested by contact with BALB/C 3T3 fibroblast cells. Each sample was tested after 24, 48 and 72 hours. The cellular vitality was verified through spectrophotometric analysis of the solution where the colour is directly related to the amount of metabolically active and living cells. The results were analyzed through…

MiceResins SyntheticBALB 3T3 CellsCell SurvivalCitotoxicity tests immunologic removable partial Denture Material testing resinSettore MED/28 - Malattie OdontostomatologicheMaterials TestingAcrylic ResinsAnimalsMethacrylatesIn Vitro TechniquesComposite Resins
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Suture needles in Oral Surgery: Alterations depending on the type and number of sutures

2011

This study examined whether the number and type of sutures used in oral surgery influence two ad hoc variables (incision plane and displaced area), which are two variables related to whether the suture needle is suitable for the task. Seventy-five TB-15 needles were studied, which were used to suture between zero and three mucosa and/subperiosteal sutures, producing 15 groups with 5 needles in each one. The incision plane and displaced area were measured for each group, which are two variables related to how the needle has worn and altered. Statistical treatment was conducted using the Kruskal-Wallis H test to compare multiple values and the Mann-Whitney U test to compare pairs. A multi-sta…

medicine.medical_specialtyMaterial testingOral surgeryOral Surgical ProceduresMaterials testingOral surgerySuture (anatomy)Third molarMedicineProspective StudiesGeneral DentistryOrthodonticsSuturesbusiness.industrySuture needlesSuture TechniquesScanning electron microscope:CIENCIAS MÉDICAS [UNESCO]SurgeryOtorhinolaryngologyNeedlesUNESCO::CIENCIAS MÉDICASResearch-ArticleSurgeryOral Surgerybusiness
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