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Yayın Dissipative dynamics and the statistics of energy states of a Hookean model for protein folding(Kluwer Academic Publishers-Plenum Publishers, 2000-07) Tüzel, Erkan; Erzan, AyşeA generic model of a random polypeptide chain, with discrete torsional degrees of freedom and Hookean spring connecting pails or hydrophobic residues, reproduces the energy probability distribution of real proteins over a very large range of energies. We show that this system with harmonic interactions, under dissipative dynamics driven by random noise, leads to a distribution of energy states obeying a modified one-dimensional Ornstein-Uhlenbeck process and giving rise Lo the so-called Wigner distribution. A tunably fine- or coarse-grained sampling of the energy landscape yields a family of distributions for the energies and energy spacings.Yayın Cation effect on gel-sol transition of kappa carrageenan(Springer, 2008-04) Pekcan, Mehmet Önder; Tarı İlgin, ÖzlemThe steady state fluorescence (SSF) technique was employed to study gel - sol transitions of kappa carrageenan in NaCl, KCl and CaCl2 solutions. Pyranine was used as a fluorescence probe for monitoring these transitions. Scattered light, I-sc and fluorescence intensity, I was monitored against temperature to determine the gel - sol (T-gs) transition temperatures and exponents. It was observed that T-gs values are strongly correlated to the NaCl, KCl and CaCl2 contents. The weight average degree of polymerization, DPw and gel fraction G, exponents (gamma and beta) were measured and found to be in accord with the classical Flory-Stockmayer Model.Yayın Effect of magnesium and osteoblast cell presence on hydroxyapatite formation on (Ti,Mg)N thin film coatings(Springer, 2016-07-19) Önder, Sakip; Çalıkoğlu Koyuncu, Ayşe Ceren Eren; Köse, Gamze Torun; Kazmanlı, Kürşat Muhammet; Kök, Fatma Neşe; Ürgen, MustafaTiN and (Ti,Mg)N thin film coatings were deposited on Ti substrates by an arc-physical vapor deposition technique. The effect of cell presence on hydroxyapatite (HA) formation was investigated using surfaces with four different Mg contents (0, 8.1, 11.31, and 28.49 at.%). Accelerated corrosion above 10 at.% Mg had a negative effect on the performance in terms of both cell proliferation and mineralization. In the absence of cells, Mg-free TiN coatings and low-Mg (8.1 at.%)-doped (Ti,Mg)N surfaces led to an early HA deposition (after 7 days and 14 days, respectively) in cell culture medium (DMEM), but the crystallinity was low. More crystalline HA structures were obtained in the presence of the cells. HA deposits with an ideal Ca/P ratio were obtained at least a week earlier, at day 14, in TiN and low-Mg (8.1 at.%)-doped (Ti,Mg)N compared with that of high-Mg-containing surfaces (>10 at.%). A thicker mineralized matrix was formed on low-Mg (8.1 at.%)-doped (Ti,Mg)N relative to that of the TiN sample. Low-Mg doping (<10 at.%) into TiN coatings resulted in better cell proliferation and thicker mineralized matrix formation, so it could be a promising alternative for hard tissue applications.Yayın Protective and risk factors associated with involved fatherhood in a traditional culture(John Wiley and Sons Inc, 2023-02) Kisbu, Yasemin; Akçinar Yayla, Berna; Kuşcul, Gönül Hilal; Bozok, Mehmet; Turunç, Gamze; Fişek, GülerObjective: Consistent with ecological systems theory and the heuristic model of parental behavior dynamics, the current study is focused on both individual and contextual factors that determine fatherhood involvement in the context of a traditional patriarchal culture. Background: Father–child interaction during the early childhood period is a salient factor in predicting later child outcomes. However, studies on antecedents of involved fatherhood are scarce, mostly concentrated on one aspect of fathering behavior, and limited to few cultural contexts. Method: Data were collected from a representative urban sample of fathers of preschoolers in Turkey (N = 1,070). Different components of fatherhood involvement were assessed to project three distinct paternal behavior dimensions as care, affection, and control. Results: Father role satisfaction, psychological value attributed to the child, and perceived family support were positively associated with involved fatherhood and higher parental warmth. Working hours per day was negatively associated with involved fatherhood, as expected. Higher life satisfaction was associated with higher positive parenting. Patriarchal views of masculinity were found to be the main predictor of parental physical punishment, controlling for all other predictors in the model. Conclusion: Study findings emphasized the importance of factors other than parenting skills that contribute to fathers' parental effectiveness. Implications: Our study's findings have implications for family practices and policies. For example, besides parenting skills, father support programs should also focus on other factors such as developing awareness of traditional masculinity norms and gender role prescriptions that can harm democratic family environments and childcare practices.Yayın Confluent edge conditions for the electromagnetic wave at the edge of a wedge bounded by material sheets(Elsevier Science, 2000-07) İdemen, Mehmet MithatThe edge conditions which dictate the asymptotic behaviour of the electromagnetic field near the edges play a crucial role in solving boundary-value problems involving boundaries having edges. In analytical studies they permit one to determine some unknown functions while in numerical investigations they enable one to improve the convergence of some processes by introducing beforehand the edge singularities into the field functions. In spite of its importance, the subject has not yet been studied sufficiently and accurately for new types of boundary conditions which are important for practical applications. This work is devoted to the analysis of wedge configurations bounded by material sheets having different constitutive parameters. The cases where the electric or the magnetic field is parallel to the edge are considered separately. It is shown that for each of these cases 81 physically different configurations are possible. However, from mathematical point of view all these configurations can be reduced only to nine canonical types. These canonical types are investigated in full detail by introducing the confluence concept which permits one to reveal also the logarithmic singularities, if any.Yayın Investigating effects of milling conditions on cutting temperatures through analytical and experimental methods(Elsevier Science SA, 2018-12) Karagüzel, Umut; Budak, ErhanCutting temperatures in milling operations have a significant impact on tool wear, size and shape tolerances and residual stresses of the machined part. Prediction and measurement of cutting temperatures in milling, on the other hand, have some challenges due to the rotary tools resulting in an intermittent process and transient thermal loadings. In this study, novel approaches are presented to model and measure the cutting tool temperature variations during milling. The model is used to predict effects of milling conditions on cutting temperatures particularly to determine a relationship between tool temperature and radial depth of cut. The model predictions are verified by measurements obtained from the developed measurement technique and the literature data.
