108 research outputs found

    Pre-Service Teachers\u27 Understanding of Geometric Reflections in Terms of Motion and Mapping View

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    In this manuscript, I describe a study of pre-service secondary mathematics teachers’ (PTs) understanding of geometric reflection in terms of a motion and a mapping views. PTs often have a motion view of geometric reflection based on their understanding of reflection line, domain, and plane. A motion view is a preliminary perspective developed prior to the construction of a mapping view. PTs need a mapping view of geometric reflection, and to be conscious of sub-concepts of a mapping view involved reflection line, domain, and plane. However, there is no clear evidence documenting how a learner’s motion view evolves to produce a mapping view. A clinical interview methodology was used to describe how mental structures occur in the movement between PTs’ motion view and the mapping view. Also, factors critical to the transition from a motion view to a mapping view were explored. Four case studies were constructed from transcript audio records, videos, and written works. Ongoing and retrospective analyses using Dubinsky’s action, process, object and schema (APOS) framework were used to examine PTs’ mental structures. The results indicated that the motion view transforms into the mapping view through the development of mental structures associated with three important sub-concepts of geometric reflection. These three sub-concepts are reflection line, domain, and plane. The results further indicated that there are series of factors that impact the development from the motion view to the mapping view. These factors are perpendicularity and equidistance properties, the role of reflection line, type of figures (circle, semicircle, interior and exterior points of the figures), the operational definition of the plane, and relations between figure and plane

    Heat-resistant hydrophobic-oleophobic coatings

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    Thermally and chemically durable hydrophobic oleophobic coatings, containing different ceramic particles such as SiO2, SiC, Al 2O3, which can be alternative instead of Teflon, have been developed and applied on the aluminum substrates by spin-coating method. Polyimides, which are high-thermal resistant heteroaromatic polymers, were synthesized, and fluor oligomers were added to these polymers to obtain hydrophobic-oleophobic properties. After coating, Al surface was subjected to Taber-abrasion, adhesion, corrosion, and thermal tests. The effects of the particle size of ceramic powders, organic matrix, and heat on the coating material were investigated. Coating material was characterized by FTIR spectrophotometer. Surface properties and thermal resistance of the coating materials were investigated by SEM and TGA analyses. After thermal curing, contact angles of these coatings with H2O and n-hexadecane were measured. It was observed that coatings like ceramic particles are more resistant against scratch and abrasion than the other coatings. Also, they are harder than coatings, which do not include ceramic particles. It was seen that coatings, containing Fluorolink D10H, have high-contact angles with water and n-hexadecane

    The formation of gradients in wet deposited coatings with photocatalytically active nanoparticles

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    A total of 81 doped and undoped anatase nano-particles were synthesised by a precipitation/co-precipitation process followed by a hydrothermal treatment to obtain increased visible light photocatalytic activity. The screening process was performed utilising a high throughput analysis system based on the photometric monitoring of the photocatalytic degradation of organic dyes (Rhodamine B, Malachite Green, Acid Blue 29). Photocatalytically active coatings were prepared with selected catalysts with high and low rankings from the screening. Degradation experiments with stearic acid could confirm the varying grades of visible light activity as seen in the screening process

    Application of spray techniques for new photocatalytic gradient coatings on plastics

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    Transparent coating systems applicable on plastics surfaces by a spray technique are presented. The coatings are based on highly photocatalytically active nanoscaled titania powders, surface modified with silanes containing organic or fluoro-organic side chains. The modification allows for the introduction of the particles in organic inorganic hybrid NANOMER® coating systems. In the wet film—due to the evaporation of the solvents—a decompatibilisation of the coated particles to the matrix results in a self-organising gradient layer formation with an up-concentration of the active particles at the interface layer between coating and air. After activation by irradiation with artificial or natural UV-light, highly active transparent photocatalytic coatings for a great variety of materials are obtained

    Maternal serum preptin levels in the pathogenesis and diagnosis of Gestational diabetes mellitus

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    Background: Gestational diabetes mellitus (GDM) is a metabolic disorder that occurs during pregnancy that increases both maternal and fetal mortality and morbidity. It was investigated whether there is a change in circulating levels of preptin, a new peptide secreted from pancreatic beta cells, due to GDM in pregnant women. The relationship between serum preptin levels with insulin and other metabolic parameters was also evaluated in these subjects. Methods: Eighty-five patients diagnosed as GDM and 89 healthy pregnant women with 75 mg oral glucose tolerance test (OGTT) was assessed in terms of serum preptin levels. Results: The serum preptin levels of the GDM group were significantly higher than those of the control group (p=0.001; p < 0.01). For the cutoff value of preptin measurement of 335.3 ng/L, the sensitivity was 97.65%, specificity was 87.64%, positive predictive value was 88.3% and negative predictive value was 97.5%. The risk of developing the disease is 294.273 times higher in patients with preptin level of 335.3 and above. Conclusions: We think that the reason for the increase in serum preptin levels in GDM is probably the response to glucose. The current results indicate that preptin plays an important role in elucidating the pathology of GDM. In addition, the search for a practical marker for the diagnosis of GDM suggests that the measurement of preptin level is promising

    Real-world efficacy and safety of Ledipasvir plus Sofosbuvir and Ombitasvir/Paritaprevir/Ritonavir +/- Dasabuvir combination therapies for chronic hepatitis C: A Turkish experience

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    Background/Aims: This study aimed to evaluate the real-life efficacy and tolerability of direct-acting antiviral treatments for patients with chronic hepatitis C (CHC) with/without cirrhosis in the Turkish population.Material and Methods: A total of 4,352 patients with CHC from 36 different institutions in Turkey were enrolled. They received ledipasvir (LDV) and sofosbuvir (SOF)+/- ribavirin (RBV) ombitasvir/paritaprevir/ritonavir +/- dasabuvir (PrOD)+/- RBV for 12 or 24 weeks. Sustained virologic response (SVR) rates, factors affecting SVR, safety profile, and hepatocellular cancer (HCC) occurrence were analyzed.Results: SVR12 was achieved in 92.8% of the patients (4,040/4,352) according to intention-to-treat and in 98.3% of the patients (4,040/4,108) according to per-protocol analysis. The SVR12 rates were similar between the treatment regimens (97.2%-100%) and genotypes (95.6%-100%). Patients achieving SVR showed a significant decrease in the mean serum alanine transaminase (ALT) levels (50.90 +/- 54.60 U/L to 17.00 +/- 14.50 U/L) and model for end-stage liver disease (MELD) scores (7.51 +/- 4.54 to 7.32 +/- 3.40) (p<0.05). Of the patients, 2 were diagnosed with HCC during the treatment and 14 were diagnosed with HCC 37.0 +/- 16.0 weeks post-treatment. Higher initial MELD score (odds ratio [OR]: 1.92, 95% confidence interval [CI]: 1.22-2.38; p=0.023]), higher hepatitis C virus (HCV) RNA levels (OR: 1.44, 95% CI: 1.31-2.28; p=0.038), and higher serum ALT levels (OR: 1.38, 95% CI: 1.21-1.83; p=0.042) were associated with poor SVR12. The most common adverse events were fatigue (12.6%), pruritis (7.3%), increased serum ALT (4.7%) and bilirubin (3.8%) levels, and anemia (3.1%).Conclusion: LDV/SOF or PrOD +/- RBV were effective and tolerable treatments for patients with CHC and with or without advanced liver disease before and after liver transplantation. Although HCV eradication improves the liver function, there is a risk of developing HCC.Turkish Association for the Study of The Liver (TASL

    Production of undoped and doped TiO2-particles and investigation of their photocatalytic activity

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    Im Rahmen dieser Arbeit wurden nano-TiO2-Partikel unter Rückfluss und durch Autoklavbehandlung hergestellt. Diese nano-TiO2-Partikel bestehen aus agglomeratfreien Anatas. Sie können ohne zusätzliche Dispergierhilfsmittel in unpolaren Lösungsmitteln wie Toluol und auch im Wasser dispergiert werden. Dotierungen des TiO2 sind durch Autolavbehandlung mit unterschiedlichen Dotiermitteln und Dotiermittelmengen durchgeführt worden. Die photokatalytischen Aktivitäten der dotierten nano-TiO2-Partikel sind durch Photodegradationen der vier unterschiedlichen Farbstoffe Rhodamin B, Acid Blue 29, Methylenblau und Malachitgrün unter Belichtung mit einem Sonnensimulator mit/ohne Kantenfilter ermittelt worden. Ein Hochdurchsatzverfahren zur schnellen Ermittlung der photokatalytischen Aktivitäten der hergestellten undotierten und dotierten nano-TiO2-Partikel wurde entwickelt. Die verwendeten Farbstoffe wurden meistens durch dotierte nano-TiO2-Partikel schneller photodegradiert als durch undotierte nano-TiO2-Partikel. Die Photodegradationsraten der Farbstoffe durch Nd(OEthOMe)3-, SnCl4-, MoCl4- und Ce(OEthOMe)4-dotierte nano-TiO2-Partikel wurden, besonders unter Belichtung mit sichtbarem Licht, erheblich verbessert. Wurden die unter Rückfluss hergestellten nano-TiO2-Partikel mit unterschiedlichen Substanzen 1-H,1-H,2-H,2-H-Perfluorooctyltriethoxysilan (FTS), Hexadecyltrimethoxysilan (HDTMS) und Palmitinsäure) Oberflächen modifiziert und die modifizierten nano-TiO2-Partikel anschließend in verschiedene NANOMER®-Systeme eingebaut, so sind TiO2-Gradienten innerhalb einer Schicht entstanden. Diese Gradientenbildung modifizierter TiO2-Partikel in den Schichten aus FTS-modifizierten nano-TiO2-Partikeln und verschiedenen Lacksystemen sind mittels SIMS-Tiefenprofil- und EDX/TEM-Analysen nachgewiesen worden. Wenn eine Schicht mit TiO2-Gradient belichtet wird, zeigt sie Superhydrophilie bzw. Selbstreinigungsfähigkeit.In this study firstly the TiO2-nanoparticles were synthesized by reflux and autoclave treatment. These nanoparticles were composed of agglomerate-free anatase. They could be dispersed in nonpolar solvent such toluene and also in water without any dispersion additive. In order to enhance the photoactivity of the TiO2 the particles of TiO2 were doped with various metalions by means of hydrothermal process. A high-throughput activity testing for the redispersed photocatalyst samples based on photometric monitoring of the photodegradation of three different organic dyes (Rhodamine B, Malachite Green, Acid Blue 29, Methylene Blue) after illumination by sun-tester light and cut-off filter (400 nm and 420 nm) restricted light was established. The photoactivity of the TiO2 under UV-illumination was enhanced by most of the used doping metalions. A greatest enhancements of the daylight photocatalytic activity were found for the samples doped with Nd(OEthOMe)3, SnCl4, MoCl4 and Ce(OEthOMe)4. The surface of highly dispersed TiO2 nanoparticles by the reflux treatment has been modified with 1-H,1-H,2-H, 2-H-Perfluorooctyltriethoxysilan, Hexadecyltrimethoxysilan und Palmitic acid. The surface-modified TiO2 nanoparticles have been suspended in the various NANOMER® systems. After applications of the suspensions on substrate by dip coating and subsequent curing the layer, the photocatalytically active layers were obtained. The analytical and microscopical investigations — SIMS-analysis and direct TEM imaging, supplemented by EDX have offered the formation of TiO2 gradients by modification of TiO2 nanoparticles within the composites during layer growth and curing. After the illumination of the layers with the TiO2-gradient were superhydrophilic respectively self-cleaning

    Production of undoped and doped TiO2-particles and investigation of their photocatalytic activity

    No full text
    Im Rahmen dieser Arbeit wurden nano-TiO2-Partikel unter Rückfluss und durch Autoklavbehandlung hergestellt. Diese nano-TiO2-Partikel bestehen aus agglomeratfreien Anatas. Sie können ohne zusätzliche Dispergierhilfsmittel in unpolaren Lösungsmitteln wie Toluol und auch im Wasser dispergiert werden. Dotierungen des TiO2 sind durch Autolavbehandlung mit unterschiedlichen Dotiermitteln und Dotiermittelmengen durchgeführt worden. Die photokatalytischen Aktivitäten der dotierten nano-TiO2-Partikel sind durch Photodegradationen der vier unterschiedlichen Farbstoffe Rhodamin B, Acid Blue 29, Methylenblau und Malachitgrün unter Belichtung mit einem Sonnensimulator mit/ohne Kantenfilter ermittelt worden. Ein Hochdurchsatzverfahren zur schnellen Ermittlung der photokatalytischen Aktivitäten der hergestellten undotierten und dotierten nano-TiO2-Partikel wurde entwickelt. Die verwendeten Farbstoffe wurden meistens durch dotierte nano-TiO2-Partikel schneller photodegradiert als durch undotierte nano-TiO2-Partikel. Die Photodegradationsraten der Farbstoffe durch Nd(OEthOMe)3-, SnCl4-, MoCl4- und Ce(OEthOMe)4-dotierte nano-TiO2-Partikel wurden, besonders unter Belichtung mit sichtbarem Licht, erheblich verbessert. Wurden die unter Rückfluss hergestellten nano-TiO2-Partikel mit unterschiedlichen Substanzen 1-H,1-H,2-H,2-H-Perfluorooctyltriethoxysilan (FTS), Hexadecyltrimethoxysilan (HDTMS) und Palmitinsäure) Oberflächen modifiziert und die modifizierten nano-TiO2-Partikel anschließend in verschiedene NANOMER®-Systeme eingebaut, so sind TiO2-Gradienten innerhalb einer Schicht entstanden. Diese Gradientenbildung modifizierter TiO2-Partikel in den Schichten aus FTS-modifizierten nano-TiO2-Partikeln und verschiedenen Lacksystemen sind mittels SIMS-Tiefenprofil- und EDX/TEM-Analysen nachgewiesen worden. Wenn eine Schicht mit TiO2-Gradient belichtet wird, zeigt sie Superhydrophilie bzw. Selbstreinigungsfähigkeit.In this study firstly the TiO2-nanoparticles were synthesized by reflux and autoclave treatment. These nanoparticles were composed of agglomerate-free anatase. They could be dispersed in nonpolar solvent such toluene and also in water without any dispersion additive. In order to enhance the photoactivity of the TiO2 the particles of TiO2 were doped with various metalions by means of hydrothermal process. A high-throughput activity testing for the redispersed photocatalyst samples based on photometric monitoring of the photodegradation of three different organic dyes (Rhodamine B, Malachite Green, Acid Blue 29, Methylene Blue) after illumination by sun-tester light and cut-off filter (400 nm and 420 nm) restricted light was established. The photoactivity of the TiO2 under UV-illumination was enhanced by most of the used doping metalions. A greatest enhancements of the daylight photocatalytic activity were found for the samples doped with Nd(OEthOMe)3, SnCl4, MoCl4 and Ce(OEthOMe)4. The surface of highly dispersed TiO2 nanoparticles by the reflux treatment has been modified with 1-H,1-H,2-H, 2-H-Perfluorooctyltriethoxysilan, Hexadecyltrimethoxysilan und Palmitic acid. The surface-modified TiO2 nanoparticles have been suspended in the various NANOMER® systems. After applications of the suspensions on substrate by dip coating and subsequent curing the layer, the photocatalytically active layers were obtained. The analytical and microscopical investigations — SIMS-analysis and direct TEM imaging, supplemented by EDX have offered the formation of TiO2 gradients by modification of TiO2 nanoparticles within the composites during layer growth and curing. After the illumination of the layers with the TiO2-gradient were superhydrophilic respectively self-cleaning

    Neurobiology of Placebo Effect

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    Placebo is defined as a substance or method that has no specific effect on the condition being treated. Placebo leads to the state of contentment and shows its effects just like a drug by the pathways in the body. Various changes formed by plasebo on the brain activation, neurotransmitters and hormones have been observed with the development of neuroimaging methods. The effects of dopamine, serotonin, and opioid systems in the formation of the placebo response; the relationship between placebo effect, reward cycle and expectation process and the role of the some specific regions in the brain where pharmacological agents acting on during the placebo response have been shown in several studies. There are similarities between hypnosis and the placebo effects and expectation of improvement is closely related to the suggesting phenomenon in the hypnosis as well as placebo responses. The formation of similar changes in the brain after administration of placebo and hypnosis associated with the expectation models and suggestions attracts attention. Neurochemical pathways in the brain constitute functional impact with many of the common mechanisms. Therefore, all of these mechanisms in the placebo response can take part in relation to each other. Although it is known that many factors may influence, understanding of the effects of placebo and viewing the changes in the brain formed by placebo have an important place for enlightening roles of psychological factors in the onset of diseases and treatment

    Neurobiology of Placebo Effect

    No full text
    Placebo is defined as a substance or method that has no specific effect on the condition being treated. Placebo leads to the state of contentment and shows its effects just like a drug by the pathways in the body. Various changes formed by plasebo on the brain activation, neurotransmitters and hormones have been observed with the development of neuroimaging methods. The effects of dopamine, serotonin, and opioid systems in the formation of the placebo response; the relationship between placebo effect, reward cycle and expectation process and the role of the some specific regions in the brain where pharmacological agents acting on during the placebo response have been shown in several studies. There are similarities between hypnosis and the placebo effects and expectation of improvement is closely related to the suggesting phenomenon in the hypnosis as well as placebo responses. The formation of similar changes in the brain after administration of placebo and hypnosis associated with the expectation models and suggestions attracts attention. Neurochemical pathways in the brain constitute functional impact with many of the common mechanisms. Therefore, all of these mechanisms in the placebo response can take part in relation to each other. Although it is known that many factors may influence, understanding of the effects of placebo and viewing the changes in the brain formed by placebo have an important place for enlightening roles of psychological factors in the onset of diseases and treatment
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