1,378 research outputs found

    Effects of contemporary orthodontic composites on tooth color following short-term fixed orthodontic treatment: A controlled clinical study

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    Background/aim: To determine the color alterations of natural teeth associated with different orthodontic composites used in comprehensive short-term treatment. Materials and methods: Twenty-two patients were treated with fixed appliances and 22 untreated subjects were also evaluated. Lower incisors were bonded with different orthodontic composites: 42 with Grengloo, 41 with Light Bond, 31 with Kurasper F, and 32 with Transbond XT. The color parameters of the Commission Internationale de l’Eclairage (CIE) were measured for each tooth with a spectrophotometer. Color assessment in relation to time, adhesive material, and their interaction was made with 2-way mixed analysis of variance (ANOVA) and 1-way ANOVA for the color differences (ΔE*). Further analyses were done using Tukey’s honestly significant difference tests and paired-samples t-tests. Results: The color of teeth was affected by treatment. The mean L* and a* values increased, whereas the mean b* values decreased. Total color differences of teeth demonstrated visible color changes clinically after treatment, ranging from 1.12 to 3.34 ΔE units. However, there were no significant differences for color of enamel. Conclusion: Teeth may be discolored with fixed appliances during treatment. Moreover, contemporary orthodontic composites have similar effects of enamel discoloration. © TÜBİTAK

    Medial olivocochlear suppression in musicians versus non-musicians

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    The medial olivocochlear efferent (MOCE) branch synapses with outer hair cells (OHCs), and the efferent pathway can be activated via a contralateral acoustic stimulus (CAS). The activation of MOCE can change OHC motile responses and convert signals that are capable of controlling the sensitivity of the peripheral hearing system in a frequency-specific manner. The aim of this study was to examine the MOCE system activity in professional musicians using transient evoked otoacoustic emission test and CAS. Musician group showed stronger suppression in all frequency bands in the presence of CAS

    Examination of Technology in Turkish Social Studies Curricula

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    AbstractThis study is designed in descriptive model because it aims to analyze 4th, 5th, 6th and 7th grade social studies curricula in a technology focused view. In this context, document analysis technique was used which is a qualitative research method. Learning areas, acquisitions and skills in social studies curricula are considered in evaluation process. In conclusion, it was seen that in social studies curricula, Science,Technology and Society learning is directly technology oriented and this learning area has strict connections with others. Technology oriented activities are also implemented as needed in other learning areas. Besides, it was determined that there are 23 technology oriented acquisitions in 4 th, 5 th, 6 th and 7 th grade social studies curricula in Turkey. Six of them are in the 4th grade, six of them are in the 5th grade, five of them are in the 6th grade and six of them in the 7th grade. In this context, technology oriented acquisitions formed 13,2% of whole acquisitions in curricula (total 174). In skill dimension “using information technologies” skill is technology oriented and it is towards the effective usage of technology

    Electrochemical determination of aripiprazole based on aluminium oxide nanoparticles modified carbon paste electrode

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    The electrochemical oxidation of aripiprazole was explored at a carbon paste electrode modified with aluminium oxide nanoparticles by cyclic voltammetry and square-wave anodic adsorptive stripping voltammetry. Experimental parameters such as carbon paste composition, scan rate, buffer pH, accumulation time, and accumulation potential were optimized in order to obtain high analytical performance. The incorporation of aluminium oxide nanoparticles into the carbon paste matrix enhanced the effective surface area of the carbon paste electrode and improved the sensitivity. On the aluminium oxide nanoparticles modified carbon paste electrode, aripiprazole exhibited an irreversible anodic peak at +1.17 V in pH 1.8 BR buffer solution. Under optimum conditions, the peak current exhibited a linear dependence with aripiprazole concentration between 0.03 and 8.0 µM with a detection limit of 0.006 ?M. The analytical applicability of the voltammetric method was evaluated by quantification of ARP in human serum samples and pharmaceutical formulations. © TÜBİTAKNKUBAP.01, YGLA.16.018This study was supported by Tekirdağ Namık Kemal University Scientific Research Projects Coodination Unit (project no: NKUBAP.01.YGLA.16.018)

    Probing the microenvironmental conditions for induction of superficial zone protein expression

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    SummaryObjectiveTo determine the in vitro conditions which promote expression of superficial zone protein (SZP).MethodsChondrocytes from 6-month-old calves were expanded in monolayer culture and the expression of SZP in alginate bead and monolayer culture was quantified with quantitative real time-polymerase chain reaction (qRT-PCR) and immunostaining. The effect of oxygen tension on SZP expression was determined by qRT-PRC analysis of cells cultured in two dimension (2D) and three dimension (3D) under hypoxic (1% pO2) or normoxic (21% pO2) conditions. Finally, to examine the effect of cyclic tensile strain on expression of SZP in 2D and 3D cultures, chondrocytes encapsulated in alginate beams or seeded on type I collagen coated polydimethylsiloxane (PDMS) chambers were subjected to 5% strain at 1 Hz, 2 h/day for 4 days or 2 h at the fourth day of culture and mRNA levels were quantified.ResultsBovine chondrocytes in monolayer showed a drastic decrease in SZP expression, similar in trend to the commonly reported downregulation of type II collagen (Col2). Chondrocytes embedded in alginate beads for 4 days re-expressed SZP but not Col2. SZP expression was higher under normoxic conditions whereas Col2 was upregulated only in alginate beads under hypoxic conditions. Cyclic mechanical strain showed a tendency to upregulate mRNA levels of SZP.ConclusionsA microenvironment encompassing a soft encapsulation material and 21% oxygen is sufficient for fibroblastic chondrocytes to re-express SZP. These results serve as a guideline for the design of stratified engineered articular cartilage and suggest that microenvironmental cues (oxygen tension level) strongly influence the pattern of SZP expression in vivo

    Pulses of Notch activation synchronise oscillating somite cells and entrain the zebrafish segmentation clock

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    Formation of somites, the rudiments of vertebrate body segments, is an oscillatory process governed by a gene-expression oscillator, the segmentation clock. This operates in each cell of the presomitic mesoderm (PSM), but the individual cells drift out of synchrony when Delta/Notch signalling fails, causing gross anatomical defects. We and others have suggested that this is because synchrony is maintained by pulses of Notch activation, delivered cyclically by each cell to its neighbours, that serve to adjust or reset the phase of the intracellular oscillator. This, however, has never been proved. Here, we provide direct experimental evidence, using zebrafish containing a heat-shock-driven transgene that lets us deliver artificial pulses of expression of the Notch ligand DeltaC. In DeltaC-defective embryos, in which endogenous Notch signalling fails, the artificial pulses restore synchrony, thereby rescuing somite formation. The spacing of segment boundaries produced by repetitive heat-shocking varies according to the time interval between one heat-shock and the next. The induced synchrony is manifest both morphologically and at the level of the oscillations of her1, a core component of the intracellular oscillator. Thus, entrainment of intracellular clocks by periodic activation of the Notch pathway is indeed the mechanism maintaining cell synchrony during somitogenesis

    Brieskorn manifolds as contact branched covers of spheres

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    We show that Brieskorn manifolds with their standard contact structures are contact branched coverings of spheres. This covering maps a contact open book decomposition of the Brieskorn manifold onto a Milnor open book of the sphere.Comment: 8 pages, 1 figur

    Effect of micronized zeolite addition to lamb concentrate feeds on growth performance and some blood chemistry and metabolites

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    This study was conducted to determine the effects of the addition of micronized zeolite (MZ) on the fattening performance, blood parameters, faecal ash and nitrogen levels of lambs fed concentrate feeds intensively. For two months 25 four-month-old Merino x Ile de France crossbred male lambs (21.1 ± 1.32 kg live weight) were fed 100 g alfalfa hay and a mixed concentrate diet containing 0%, 1%, 2% or 3% additional MZ. At the end of the study, bodyweight gain and feed consumption were not affected by the treatments. Similarly, the addition of up to 2% MZ to the diet did not affect slaughter weight, hot carcass or cold carcass weights, but they decreased at 3% MZ inclusion. No differences were observed between the groups in terms of blood urea nitrogen, plasma glucose, serum creatinine, triglyceride, sodium, potassium and chlorine concentration. However, serum total protein, calcium and phosphorus concentrations were affected by MZ supplementation. The addition of MZ to the ration did not affect the faecal dry matter content and total nitrogen level, yet it increased the ash content of the faeces. Consequently, it was demonstrated that the addition of up to 2% MZ to lamb grower feed does not have a negative impact on performance and carcass yield of the animals, but affects serum total protein, calcium and phosphorus concentrations

    Robust Rolling Horizon Optimisation Model for Offshore Wind Farm Installation Logistics

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    Our approach can be considered as both proactive and reactive, since uncertainty is considered both in creating the initial schedule and the schedule can be updated in real-time
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