Characterization,in vitro bioactivity and biological studies of sol-gel-derived TiO2 substituted 58S bioactive glass

Bioactive glasses (BGs) have been used for bone formation and bone repair processes in recent years. This study investigated the titanium substitution effect on 58S BGs (Ti-BGs) 60SiO₂-(36 − X)CaO-4P₂O₅-XTiO₂ (X = 0, 3, and 5 mol.%) prepared by the sol-gel technique, and the main goal was to find the optimum amount of titanium in Ti-BGs. Synthesized BGs, which were investigated after immersion in simulated body fluid (SBF), were tested by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy. Moreover alkaline phosphate (ALP) activity, 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and antibacterial studies were employed to investigate the biological properties of Ti-BGs. According to the FTIR and XRD test results, hydroxyapatite (HA) formation on Ti-BGs surfaces was confirmed. Meanwhile, the presence of 5 mol.% compared to 3 mol.% increased the HA grain distribution and their size on the Ti-BGs surface. Additionally, MTT and ALP results confirmed that the optimal amount of titanium substitution in BG was 5 mol.%. Since 5 mol.% Ti incorporated BG (BG-5) had the highest biocompatibility level, antibacterial properties, maximum cell proliferation, and ALP activity among the synthesized Ti-BGs, it is presented as the best candidate for further in vivo investigations.     

Study of macromolecular interactions in low‐fat brined cheese modified with Zedu gum

The functionality of Zedu gum as a fat mimetic in low‐fat brined cheese was studied. The physicochemical, textural, rheological, microstructural and sensory properties of cheese samples modified with 0.1% and 0.25% of Zedu gum were compared to those of control cheeses (low‐fat and full‐fat cheeses with no fat mimetic) during ripening. To obtain further information about the cheeses' structure and interactions between macromolecules (casein protein and Zedu gum), other parameters were analysed by differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy. Incorporation of Zedu gum into low‐fat cheese caused an open microstructure and softer texture in comparison with the control low‐fat cheese. The thermal properties and FTIR spectra of the cheeses were influenced by both fat mimetic and ripening time. On days 1 and 60 of ripening time, the lower value of enthalpy of the low‐fat cheese with 0.25 g of Zedu gum/kg of milk (AS 0.25) in comparison with control low‐fat cheese could have been due to the electrostatic nature of the interactions between Zedu gum and casein protein. On both days, the FTIR spectrum of AS 0.25 showed a well separated absorption at 1746 cm^?1 possibly due to the formation of ester groups as a result of the interaction of the carbonyl groups in Zedu gum with the hydroxyl groups of some amino acids in casein.     

Electrochemical pseudocapacitors of different compounds and nanocomposite of manganese: an introduction and review to it in recent studies

Journal of Materials Science: Materials in Electronics - This review gives an overview of the synthesis, surface, and electrochemical investigations over Mn-based compounds in the development of...     

Solving Detour‐Based Fuel Stations Location Problems

This article studies the problem of locating fuel stations to minimize the extra cost spent in refueling detours, which belongs to a class of discretionary service facility location problems. Unlike many studies of similar problems in the literature, the proposed model considers capacity constraints and compares different ways to incorporate them in the formulation. Note that ignoring the capacity constraint results in nonoptimal and unrealistic solutions. The proposed models are solved using both an off‐the‐shelf solver (CPLEX) and a specialized meta‐heuristic method (Simulated Annealing) developed in this study. The solution methods are tested and compared in two case studies; a test benchmark network and a large‐scale network. An effort to overcome the memory limitation of CPLEX through more compact formulation was partially successful: it results in a model that is less tightly bounded by its linear relaxation and hence is much more difficult to solve. In contrast, the Simulated Annealing algorithm scales better and is able to consistently yield high‐quality solutions with a reasonable amount of computation time.     

Contactless Stimulation and Control of Biomimetic Nanotubes by Calcium Ion Gradients

Membrane tubular structures are important communication pathways between cells and cellular compartments. Studying these structures in their native environment is challenging, due to the complexity of membranes and varying chemical conditions within and outside of the cells. This work demonstrates that a calcium ion gradient, applied to a synthetic lipid nanotube, triggers lipid flow directed toward the application site, resulting in the formation of a bulge aggregate. This bulge can be translated in a contactless manner by moving a calcium ion source along the lipid nanotube. Furthermore, entrapment of polystyrene nanobeads within the bulge does not tamper the bulge movement and allows transporting of the nanoparticle cargo along the lipid nanotube. In addition to the synthetic lipid nanotubes, the response of cell plasma membrane tethers to local calcium ion stimulation is investigated. The directed membrane transport in these tethers is observed, but with slower kinetics in comparison to the synthetic lipid nanotubes. The findings of this work demonstrate a novel and contactless mode of transport in lipid nanotubes, guided by local exposure to calcium ions. The observed lipid nanotube behavior can advance the current understanding of the cell membrane tubular structures, which are constantly reshaped during dynamic cellular processes.     

The effect of ovine and bovine milk on the textural properties of Lighvan cheese during ripening

The effect of milk origin on the physicochemical characteristics, microstructure and texture of Lighvan cheese was investigated over a 90‐day ripening period. Besides fat, other physicochemical properties of Lighvan cheese were affected by milk type. The moisture content of Lighvan cheese decreased when half or all the ovine milk was substituted with bovine milk. The Lighvan cheese's microstructural properties and porosity were affected by type of milk and ripening time. Compaction of cheeses manufactured from ovine and mixed ovine and bovine milk is similar, and more than that of bovine Lighvan cheese. Ovine Lighvan cheese is harder and less brittle than bovine and mixed bovine and ovine.     

Nonlinear elastoplastic analysis of pressure sensitive materials

When structures undergo extreme loading conditions, the materials pass the elastic limits. Therefore, to preserve economy as well as safety, it is essential to perform a realistic elastoplastic analysis using the constitutive equations in plasticity. On the other hand, computing the stress alongside its associated variables on Gauss points is a delicate process and virtually the most important part of these analyses. In this study, an efficient stress-updating technique is presented for the constitutive rate equations of the pressure sensitive materials such as concrete, rock, soil and some kind of metals. Accordingly, the Drucker–Prager plasticity is utilized to consider the hydrostatic pressure in addition to the J ₂-invariant of the deviatoric stress. Moreover, the isotropic and kinematic hardenings are used to take into account more realistic behavior of the materials. Finally, a wide range of numerical tests is carried out to show the performance of the presented method together with the application of the suggested formulations in elastoplastic analysis of a gravity dam.     

Empirical Modeling of Starch Ester Synthesis from Octenylsuccinic Anhydride

In the present work, response surface methodology (RSM) was used to determine the mathematical relationship between octenylsuccinic anhydride (OSA) treated maize starch and the octenylsuccinylation reaction conditions. A second‐order polynomial model was chosen to approximate the relationship between the response variable (y, as the degree of substitution “DS” used to define the extent of the octenylsuccinylation) and the three regressors, x₁ as the temperature, x₂ as the time and x₃ as the pH. Analysis of variance (ANOVA) showed a high R² coefficient of 0.9905, thus ensuring a satisfactory adjustment of the selected model with the experimental data. Only temperature‐pH interaction was found to have a non‐significant effect. The positive sign for the regression coefficient of the temperature variable indicated that the y_DS increased with the increased levels of this factor from 25 to 45°C. The negative sign for the coefficient of time and also pH indicated that y_DS decreased as either the time or pH increased in the region of the tested range. The negative coefficients of the interaction between x₂ and x₃ indicated that a simultaneous increase in reaction time with decrease in pH of the esterification reaction led to an increase in y_DS. Maize starch octenylsuccinate synthesis on basis of its DS value was optimized for the three independent variables tested in this study. The predicted value for the DS was 0.02 where temperature, time and pH of the reaction were 28.0°C, 8.1 h, and pH 7.11, respectively. Results of some of the selected physicochemical properties of starch, tested in the present work were also discussed.