Iranian Journal of Materials Science and Engineering

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Single crystals of double crystalline block copolymers of poly(ethylene glycol) (PEG)-b-poly(ε-caprolactone) (PCL) and PEG-b-poly(L-lactide) (PLLA) were grown from dilute solution in homo- and mixed-brush systems. Crystallization behavior of biodegradable one end-restricted crystallizable PCL and PLLA chains in homo- and mixed-brush nanostructures were investigated. Chemical and physical circumstances of crystallizable brushes were altered. Physical environment was adjusted by amorphism/crystallinity and rigidity/flexibility of neighboring brushes. Chemical environment was manipulated by interaction and miscibility of various brushes. Distinct single crystals were grown with mixed-brushes of amorphous-crystalline (polystyrene (PS), poly(methyl methacrylate) (PMMA), PCL and PLLA, double crystalline (PCL/PLLA), and rod-crystalline polyaniline (PANI)/PCL or PLLA. Surrounding was only effective on hindrance or nucleation commencement of crystallization for crystallizable brushes and had no effect on crystallization features. Novel three-layer fully single crystalline nanostructures, whose characteristics were fixed via changing the crystallization temperature, were also developed. For long crystallizable tethers, crystallization increased both brush and substrate thicknesses. 

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Abstract
In this research, Gelatine (GEL)/ Chitosan (CH) wound dressing was prepared and irradiated with gamma rays from ⁶⁰Co source for wound healing applications. GEL-CH composite characterization and functional properties were determined. The structural changes occurring after γ-irradiation at doses from 5 to 25 kGy were reported by physico-chemical techniques such as Electron Paramagnetic Resonance (EPR), Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS) studies. The antioxidant capacity was studied using DPPH (1,1-diphenyl-2-picrylhydrazyl free radical) scavenging and the antibacterial activities of Staphylococcus aureus and Escherichia coli were observed using liquid medium. Results revealed that EPR spectroscopy of un-irradiated GEL-CH showed 2 paramagnetic centers correspond to g=2.077 and g= 2.079. After irradiation, no active centre was appeared. A dose-dependent decrease in the central signal intensity was detected, then the EPR signal intensity almost disappears at 20 kGy. Gamma rays caused a slight increase in ion conductivity. FTIR suggest a slightly crosslinking phenomenon at 20 kGy. The XRD analysis does not show peak indicating crystallinity between a range of 2θ (15–30°). Moreover, γ-irradiation elevated the Scavenging DPPH radical activity (0.75 ± 0.07%). Gamma rays did not affect the antibacterial activity of GEL-CH wound dressing against pathogenic bacteria. The innovative results showed that the required γ-radiation for sterilization was ranged from 5 to 25 kGy. It permits to improve the physico-chemical and biological properties and maintain the native structural integrity of the GEL/ COL wound dressing

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Abstract
Gelatin (GEL) is most extensively used in various fields, particularly in therapeutics and pharmaceuticals. GEL was extracted from goat skin using hot temperature extraction process and compared with that of commercial GEL. The physico-chemical characterization and functional properties were investigated by using temperature denaturation (T_d), water-holding and fat-binding capacities (WHC and FBC), colour measurement and UV-light spectrum. In vitro biocompatibility was studied for the first time and was evaluated by blood coagulation index (BCI) and haemolytic tests for using as wounds dressing. The results revealed thermal stability of goat GEL at T_d 37°C. WHC and FBC capacities represented 2.5 and 1.2 g/ml, respectively. The hunter colour spaces a*, b* and L* showed a -0.27, -1.97 and 25.23 values, respectively. UV-Vis absorption spectrum of the goat GEL showed a maximum absorption peak at 280 nm. The in vitro anticoagulant activities of extracting GEL were higher than 70% after incubation for one hour. After being in contact with red blood cells for 1 h, the haemolysis ratio increased from to 0.46 to 1.4 when the concentration of goat GEL increased from 1 to 50 mg/ml suggesting the safety of the tested samples. These results suggest that thromboresistivity and hemocompatibility of this biopolymer retained the biological activity of our samples for biomaterial applications. According to this, goat GEL successfully competes with, and significantly could be useful for substitution of bovine in wound healing.

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  Fe₃O₄/ZnO/CuO nanocomposites with various molar ratios of CuO were successfully synthesized. Sol-gel method was used to syntehesize nanocomposite materials at a low temperature. A set of experiments, including X-ray diffraction (XRD), Dynamic Light Scattering (DLS), scanning electron microscopy (SEM), and UV-Vis spectroscopy, was used to confirm the successful synthesis of Fe₃O₄/ZnO/CuO nanocomposites in crystalline form.
The photocatalytic activity of the samples was investigated via the degradation of methylene blue (MB) dye
from synthetic wastewater under three distinct conditions: visible light, ultraviolet light, and a combination of visible light with ultrasonic treatment. Fe₃O₄/ZnO/CuO nanocomposite with a molar ratio of 1:1:0.5 showed the highest photocatalytic activity when irradiated with either visible or ultraviolet light. Furthermore, when visible light was combined with ultrasonic treatment, complete (100%) removal of methylene blue was achieved within 120 minutes. The results demonstrate that these nanocomposites are efficient catalysts for wastewater treatment through the removal of organic pollutants Fe₃O₄/ZnO/CuO nanocomposites with various molar ratios of CuO were successfully synthesized. Sol-gel method was used to syntehesize nanocomposite materials at a low temperature. A set of experiments, including X-ray diffraction (XRD), Dynamic Light Scattering (DLS), scanning electron microscopy (SEM), and UV-Vis spectroscopy, was used to confirm the successful synthesis of Fe₃O₄/ZnO/CuO nanocomposites in crystalline form.
The photocatalytic activity of the samples was investigated via the degradation of methylene blue (MB) dye
 from synthetic wastewater under three distinct conditions: visible light, ultraviolet light, and a combination of visible light with ultrasonic treatment. Fe₃O₄/ZnO/CuO nanocomposite with a molar ratio of 1:1:0.5 showed the highest photocatalytic activity when irradiated with either visible or ultraviolet light. Furthermore, when visible light was combined with ultrasonic treatment, complete (100%) removal of methylene blue was achieved within 120 minutes. The results demonstrate that these nanocomposites are efficient catalysts for wastewater treatment through the removal of organic pollutants