Search results for " testing"
showing 10 items of 1713 documents
In vitro comparison of flexural strength and elastic modulus of three provisional crown materials used in fixed prosthodontics
2013
Objectives: To evaluate and compare the flexural strength and the elastic moduli of three provisional crown materials (methyl methacrylate based autopolymerized resin, bis acryl composite based autopolymerized resin and urethane dimethacrylate based light polymerized resin) after storing in artificial saliva and testing at intervals of 24 hours and 7 days. Study design: A metal master mould with four slots of dimensions 25x2x2 mm was fabricated to obtain samples of standard dimensions. A total of 135 specimens were thus obtained with 45 each of three provisional materials. Further 15 samples of each group were tested after storing for one hour at room temperature and again at intervals of 2…
Impact of freezing rate on electrical conductivity of produce
2013
The aim of this work was to compare the effects of freezing rate on electrical conductivity of potatoes, carrots and apples. Electrical conductivity tests were conducted on a custom ohmic cell while samples texture was measured by means of a universal testing machine. The raw un-pretreated samples were used as control. This study showed that freezing pre-treatments lead to differences in electrical conductivity of considered samples, producing structural damage, the latter being relatively more severe when the tested products undergo ohmic treatment.
Role of coefficient of thermal expansion on bond strength of ceramic veneered yttrium-stabilized zirconia
2017
Background Incompatible coefficient of thermal expansion (CTE) is supposed to be a reason for chipping of ceramic veneered zirconia. This study evaluates the effect of veneering ceramic at varied CTE on bond strength to zirconia. Material and Methods Zirconia disks (Z, O 10 mm, 1.0 mm thickness) were prepared from Y-TZP (Cercon®) and sintered at 1350°C for 6 hours. All zirconia disks were veneered with ceramics ((O 7.0 mm, 1.5 mm thickness) with varied CTE including VITADur® alpha (VDα), VITAVM®7 (VM7), VITAVM®9 (VM9), Cercon® ceramkiss (CCK), IPSe.max® ceram (IeC), and IPS dSIGN® (IdS) (n=15). The specimens were thermo-cycled (5-55 °C, 500 cycles) prior to determine the shear bond strength…
Effect of different sintering process on flexural strength of translucency monolithic zirconia
2018
Background Sintering process is responsible for the strength of zirconia restoration. This study evaluated the effect of different sintering temperatures and sintered-holding times on flexural strength of translucency monolithic zirconia. Material and Methods One hundred and thirty five zirconia bar specimens (width-length-thickness = 10×20×1.5 mm) were prepared from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic and randomly divided into nine groups to be sintered at different temperatures [decreasing- (SD, 1350°C), regular- (SR, 1450°C), and increasing- (SI, 1550°C) sintering temperature] and different sintered-holding times [shortening- (HS, 60 min), regular- (HR, …
Fracture resistance of roots filled with three different obturation techniques
2012
Objectives: The aim of this study was to compare in vitro root fracture resistance following root canal filling with AH 26 using lateral condensation, BeeFill, and Thermafil techniques. Study Design: Eighty extracted human mandibular premolars with similar dimensions were selected. In order to standardize the roots, measurements were taken in two separate regions of the teeth—at the cemento-enamel junction and 8 mm apically from the junction—buccolingual as well as mesiodistal for every tooth. Teeth were then randomly divided into five groups (n=16). With the exception of the non-prepared group (Group 1), instrumentation was done in all groups. In group 2, instrumentation but no filling was…
Influence of artificial aging and ZrO2 nanoparticle-reinforced repair resin on the denture repair strength
2019
Background The purpose of this study was to evaluate the effect of aging process on the tensile strength (TS) of repaired acrylic denture base using ZrO2 nanoparticles (nano-ZrO2)-reinforced autopolymerized resin. Material and Methods A total of 240 heat-polymerized acrylic resin specimens (n=10) were prepared and sectioned creating 2 mm-repair-gap. Autopolymerized acrylic resin, pure and modified with 2.5, 5, and 7.5wt% nano-ZrO2 were used for specimens repair. TS of repaired specimens were measured using the universal testing machine after water immersion at 37oC for 2, 7 and 30 days. At each time interval, half the immersed specimens underwent thermo-cycling aging process (5000 cycles at…
Construct validity of the Moral Development Scale for Professionals (MDSP)
2011
Olle Söderhamn1,2, John Olav Bjørnestad1, Anne Skisland1, Christina Cliffordson21Faculty of Health and Sport Sciences, University of Agder, Grimstad and Kristiansand, Norway; 2Department of Nursing, Health and Culture, University West, Trollhättan, SwedenAbstract: The aim of this study was to investigate the construct validity of the Moral Development Scale for Professionals (MDSP) using structural equation modeling. The instrument is a 12-item self-report instrument, developed in the Scandinavian cultural context and based on Kohlberg’s theory. A hypothesized simplex structure model underlying the MDSP was tested through structural equation modeling. …
Vēža ģenētiskās testēšanas laboratorijas izveide Rīgā
2016
Onkoloģiskā saslimšana ir mūsdienās viena no smagākajām diagnozēm, no kuras ik gadu mirst liels cilvēku skaits pasaulē un Latvijā. Katru gadu pieaug pacientu skaits, kuriem ir diagnosticēts kāds no ļaundabīgā audzēja veidiem. Onkoloģijas pacienti ir visas pasaules mēroga problēma, un arī Latvijā vēža pacientu skaita pieaugums ir epidēmijas līmenī pašlaik. Diemžēl Latvijā ir novērojama tendence, ka vēzis tiek diagnosticēts vēlajās tā stadijās. Vēža diagnosticēšana tā agrākajā stadijā nozīmē pacienta dzīvildzes rādītāju pagarinājumu vai pat slimības remisiju. Vēža ģenētika sniedz visaptverošu informāciju par vēža slimības attīstību, tās iespējamajām lokācijām un daudzos gadījumos ar ģenētiskā…
A new series of π-extended tetrathiafulvalene derivatives incorporating fused furanodithiino and thienodithiino units: a joint experimental and theor…
2004
A new family of tetrathiafulvalenes has been prepared. The materials exhibit complex redox behaviour related to the electronic influence of the 1,4-dithiin moieties embedded within the framework of the molecules. The X-ray crystal structure of compound 4 reveals an unusual non-planar conformation of the heterocyclic compound, with the TTF fragment adopting a boat conformation. Theoretical calculations, performed at the DFT level (B3P86/6-31G*), confirm the boatlike structure (C2v symmetry) as the most stable conformation for this family of tetrathiafulvalenes. Upon oxidation, electrons are extracted from the whole molecule and the radical cations and dications remain highly distorted from p…
Heart rate responses during the modified six-minute walk test among Special Olympics athletes
2021
Objective: The construct validity of the modified six-minute walk test (m6MWT) was examined by addressing the following questions: 1) do participants attain a steady state plateau in heart rate (HR) within the range of 110-150 beats per minute? 2) at what percentage of their predicted HR maximum were participants during each minute of the test? Material and Methods: Participants were 36 (male=56%) Special Olympics athletes aged 34.4 years (SD = 12.7). Following familiarization, participants completed the m6MWT while wearing a Polar Team 2 heart rate monitor. Results: By the end of the first minute, average heart rate was 120bpm, and a factorial repeated measures ANOVA revealed that steady s…