Giresun University

Despite acknowledging the complementary role of chemical equilibrium-based pedagogical treatments on students’ academic performance, the related science education literature has not examined their practical effectiveness and significance via a meta-analysis method. Therefore, this study intends to meta-analytically explore their effectiveness in improving students’ academic performance. It included 55 studies (k) from 51 unique sources. The results of the meta-analysis showed that the overall effect-size (Hedges’ g = 1.028) fell into the large effect. This means that the treatments are more effective in enhancing students’ academic performance of chemical equilibrium than the controlled ones. Nevertheless, the variability in the effect-sizes revealed the importance of the treatment types and educational contexts. Also, the results indicated that the moderator variables were statistically non-significant (p > 0.05) but categorically played a crucial role at predicting the students’ academic performance through the treatments. Given the descriptive findings, the current meta-analysis offers the following individual moderator levels to better teach and measure the topic “chemical equilibrium”: university (for educational level), inquiry-based learning (for type of treatment), open-ended question (for question type) and teacher (for practitioner). Of course, chemistry teachers and science educators should take into consideration the role of educational contexts in learning chemical equilibrium, while deciding the type of treatment to teach it.

Limited studies exist on the application of welded duplex stainless steel as a temporary implant material. Various methods have been employed to enhance the biocorrosion resistance and biocompatibility of metallic implant materials. In this study, the effect of welding heat input on the biocorrosion behavior and biocompatibility of AISI 2205 duplex stainless steel joined by laser beam welding was investigated. Microstructure and microtexture characterization analyses were also conducted. Electrochemical tests were performed in a simulated body fluid (SBF) environment to evaluate the biocorrosion properties of the welded samples. The results indicated that increasing the welding heat input improved corrosion resistance. This improvement was attributed to the increased austenite volume fraction, larger grain size, and a higher high-angle grain boundary (HAGB) ratio resulting from the higher heat input. Furthermore, it was observed that increasing the welding heat input decreased the water contact angle of the weld zone. In vitro biocompatibility studies were carried out using the MTT assay with an hFOB cell line. Based on the results obtained on days 7, 14, 21, and 28 of incubation, cell viability remained at acceptable levels across all groups. Metal ion release (Cr, Fe, Ni, Mn, and Mo) into the hFOB medium was analyzed using inductively coupled plasma mass spectrometry (ICP-MS), and the results showed that higher heat input reduced ion release. Finally, bacterial adhesion tests performed with Escherichia coli revealed that the welding process influenced bacterial attachment. Specifically, higher heat input promoted bacterial adhesion, which was likely associated with the increased surface roughness.

In this study, atomic size-dependent and first-order shear-deformable free vibration analysis of nanorings embedded in a fully elastic medium is performed. Although many continuous systems, such as nanobeams, nanorods, and nanoplates, have been modeled with nonlocal elasticity and the significance of shear deformations in their mechanical analyses has been investigated, nanoscaled rings have not been examined in this context. Therefore, the present study provides a novel contribution by integrating nonlocal elasticity, shear deformation, and elastic medium effects for nanorings. According to this, firstly, by combining the equilibrium equations of nanorings with the constitutive equations of nonlocal elasticity, shear force and bending moment are obtained. Then, the frequency equation is attained by solving a set of equations dependent on two infinite series. The nondimensional frequencies of in-plane free vibration of the nanoring structure are computed under different parameters. Numerical calculations are discussed in detail. Additionally, the mechanical behavior of shear-deformable nanorings is compared with nanorings without shear deformation effects. The present study provides a unified formulation that simultaneously accounts for atomic-scale effects, transverse shear deformation, and elastic foundation interaction. This integrated approach enables a more realistic prediction of vibration characteristics of nanoring-based nano-electro-mechanical systems.

This study aimed to determine whether ectoine (ET), a bacterial compatible solute, can mitigate the adverse effects of nickel (Ni) toxicity in wheat plants. Treatments included 50 and 75 ppm Ni, with ET applied at 5 mM and 10 mM concentrations. Results showed that Ni stress significantly increased nickel accumulation in plant tissues (from 348 ppb in the control to 17.203 ppb under 50 ppm Ni), while reducing chlorophyll content from 1.38 to 1.01. However, application of 10 mM ET effectively ameliorated these effects by reducing nickel levels to 6.610 ppb (a 61.56

In this study, silver nanoparticles (AgNPs) were synthesized through a green chemistry approach using roasted hazelnut inner shells, an abundant agricultural byproduct. The hazelnut shell-derived AgNPs (HIS-AgNPs) were characterized by UV-visible spectroscopy, FT-IR, SEM, TEM, XRD and zeta potential. UV-vis revealed a surface plasmon resonance peak at 436 nm, while SEM showed spherical particles of 67.8 +/- 25.7 nm in size. HIS-AgNPs exhibited antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, with inhibition zones of 10, 11, and 15 mm and MIC values of 250, 125, and 62.5 & micro;g mL(-1), respectively. They also strongly inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with IC50 values of 4.1 and 2.9 & micro;g mL(-1), suggesting relevance for neurodegenerative disorders. In addition, HIS-AgNPs achieved > 90% photocatalytic degradation of methylene blue under sunlight within 3 h, following pseudo-first-order kinetics. Overall, this work demonstrates the sustainable conversion of hazelnut waste into multifunctional AgNPs with promising biomedical and environmental applications.