Effects of opioid-type stressors on serum digoxin-like immunoreactivity in rats

The effects of opioid-type stressors (immobilization, electric footshock and forced swimming) on serum digoxin-like immunoreactivity (SDLI) were investigated in rats. All of the stressors significantly elevated the SDLI. Naloxone treatment after application of stressors prevented the elevation of SDLI, whereas naloxone treatment alone did not cause any significant changes. The observed increase in SDLI in this study may be attributed to the actions of endogenous opioid peptides released during stress

Is case-based learning an effective teaching strategy to challenge students' alternative conceptions regarding chemical kinetics?

Background: Case-based learning (CBL) is simply teaching the concept to the students based on the cases. CBL involves a case, which is a scenario based on daily life, and study questions related to the case, which allows students to discuss their ideas. Chemical kinetics is one of the most difficult concepts for students in chemistry. Students have generally low levels of conceptual understanding and many alternative conceptions regarding it. Purpose: This study aimed to explore the effect of CBL on dealing with students' alternative conceptions about chemical kinetics. Sample: The sample consists of 53 high school students from one public high school in Turkey. Design and methods: Nonequivalent pre-test and post-test control group design was used. Reaction Rate Concept Test and semi-structured interviews were used for data collection. Convenience sampling technique was followed. For data analysis, the independent samples t-test and ANOVA was performed. Results: Both concept test and interview results showed that students instructed with cases had better understanding of core concepts of chemical kinetics and had less alternative conceptions related to the subject matter compared to the control group students, despite the fact that it was impossible to challenge all the alternative conceptions in the experimental group. Conclusions: CBL is an effective teaching method for challenging students' alternative conceptions in the context of chemical kinetics. Since using cases in small groups and whole class discussions has been found to be an effective way to cope with the alternative conceptions, it can be applied to other subjects and grade levels in high schools with a higher sample size. Furthermore, the effect of this method on academic achievement, motivation and critical thinking skills are other variables that can be investigated for future studies in the subject area of chemistry. © 2012 Copyright Taylor and Francis Group, LLC

Protective role of immobilization on ouabain-induced arrhythmias

The effects of the opioid-type stressor; immobilization, on severity of ounbain-induced cardiac arrhythmias and the possible involvement of serum catecholamines were investigated in rats. Immobilization significantly reduced the number of ventricular premature beats and the incidence of ventricular tachycardia episodes. The arterial serum catecholamine levels (A, NA and DA), measured immediately after the stressor application, were increased significicantly and were in negative correlation with the arrhythmia parameters. Both changes were reversed by naloxone (5 mg/kg) treatment after application of immobilization. The effects observed in this study may be attributed to the actions of endogenous opioid peptides released during stress

Mechanical and Thermal Properties of Pumice Powder Filled PPS Composites

Recently, it is common application to use particle materials as fillers to improve engineering properties and lower the cost of finished product. Pumice powder is cheaper than most of traditional particle fillers, however use of pumice powders as a reinforcing material in composites has not been studied in literature. Hence, in this study we have investigated the mechanical and the thermal properties of pumice powder filled polyphenylenesulphide (PPS) composites. PPS composites were reinforced with pumice powder at different loading rates (0, 1, 3.5, and 10 wt%) and they were manufactured by twin screw extruder and injection molding machine. Thermal properties were investigated by thermogravimetric analysis and differential scanning calorimeter methods. Moreover, mechanical properties such as barcol hardness, tensile strength, and modulus of samples were investigated. Thermal properties of composite samples have varied significantly depending on the loading rate. Also mechanical properties of pumice powder filled PPS composites have showed better results than pure PPS. According to test results both of mechanical and thermal properties of composites have improved with pumice powder reinforcement and it is determined that pumice powders can be used instead of traditional particle fillers

Synthesis and characterization of sugar-based methacrylates and their random copolymers by ATRP

Various sugar-based methacrylate monomers have been prepared and randomly copolymerized with methyl methacrylate (MMA) using classical atom transfer radical polymerization (ATRP). Firstly, four different sugar-based methacrylates are synthesized by two-step method: (i) etherification of protected monosaccharides with epichlorohydrin and (ii) following ring-opening reaction of obtained epoxides with methacrylic acid (MAA) in the presence of triethylamine. Next, these monomers are copolymerized with MMA via ATRP at 90 °C to obtain corresponding random copolymers. The molecular weights of the copolymers are determined by both GPC (gel permeation chromatography) and 1H-NMR (nuclear magnetic resonance spectroscopy) analyses and found as 10600~16800 and 12200~18500 g/mol, respectively. Moreover, the copolymer compositions are also determined by 1H-NMR analysis using characteristic signals of the monomers and found as about 94.1~97.8%, which are good agreement with feeding ratio. In addition, the glass transition temperatures of copolymers are found as 101.2~102.9 °C by changing type and composition of sugar-based methacrylate monomers. Overall, a series of well-defined random copolymers comprising different sugar-based methacrylates and methyl methacrylates were successfully synthesized by classical ATRP method

ATA50 telescope: Hardware

3rd Workshop on Robotic Autonomous Observatories --7 October 2013 through 11 October 2013 -- --ATA50 Telescope is a new telescope with RC optics and 50 cm diameter. It was supported by Atatürk University Scientific Research Project (2010) and established at about 2000 meters altitude in city of Erzurum in Turkey last year. The observations were started a few months ago under the direction and control of Atatürk University Astrophysics Research and Application Center (ATASAM). The technical properties and infrastructures of ATA50 Telescope are presented and we have been working on the robotic automation of the telescope as hardware and software in order to be a ready-on-demand candidate for both national and international telescope networks

ACTA PHYSICA POLONICA A Mechanical and Thermal Properties of Pumice Powder Filled PPS Composites

Recently, it is common application to use particle materials as llers to improve engineering properties and lower the cost of nished product. Pumice powder is cheaper than most of traditional particle llers, however use of pumice powders as a reinforcing material in composites has not been studied in literature. Hence, in this study we have investigated the mechanical and the thermal properties of pumice powder lled polyphenylenesulphide (PPS) composites. PPS composites were reinforced with pumice powder at dierent loading rates (0, 1, 3.5, and 10 wt%) and they were manufactured by twin screw extruder and injection molding machine. Thermal properties were investigated by thermogravimetric analysis and dierential scanning calorimeter methods. Moreover, mechanical properties such as barcol hardness, tensile strength, and modulus of samples were investigated. Thermal properties of composite samples have varied signicantly depending on the loading rate. Also mechanical properties of pumice powder lled PPS composites have showed better results than pure PPS. According to test results both of mechanical and thermal properties of composites have improved with pumice powder reinforcement and it is determined that pumice powders can be used instead of traditional particle llers