Osteogenic activities of polymeric soybean oil-g-polystyrene membranes

A novel biocompatible copolymer membrane was synthesized and characterized for use in guided bone regeneration using polymeric soybean oil-g-polystyrene (PSO-g-PS) graft copolymer which was successfully obtained by free radical polymerization of styrene initiated by PSO peroxide as a macroinitiator at 80 °C. Osteoblastic cellular activities of MC3T3-E1 cells on PSO-g-PS membranes with different soybean oil composition (PSO-g-PS1, PSO-g-PS2, and PSO-g-PS3) were evaluated. Nuclear magnetic resonance (¹H NMR) spectra showed that PSO inclusion (mol%) was found to be 27, 69, and 51 % for PSO-g-PS1, PSO-g-PS2, and PSO-g-PS3 membranes, respectively. Superior biocompatibility of the PSO-g-PS membranes was determined compared to polystyrene tissue culture plates (TCPS) as positive control. Cell proliferation was enhanced on PSO-g-PS2 and PSO-g-PS3 membranes compared to PSO-g-PS1 membranes (p < 0.001), and a statistically significant higher ALP value of MC3T3-E1 cells on PSO-g-PS2 membranes (p < 0.05) suggested that proliferation and differentiation of preosteoblastic on PSO-g-PS membranes were enhanced with regard to soybean oil content within the membranes. Thus, the present study suggests that PSO-g-PS2 membranes, which showed a favorable biological environment for the preosteoblastic cells, can be well suited for bone tissue engineering applications.     

Optimization of the Wet Mechanochemical Process Conditions of SrSO4 to SrCO3 and (NH4)2SO4 by Using Response Surface Methodology

The wet mechanochemical process was optimized for insoluble SrCO₃ and soluble (NH₄)₂SO₄ formation from celestite (SrSO₄)-(NH₄)₂CO₃-H₂O mixtures in a planetary ball mill by Box-Behnken design (BBD). The products formed during wet milling were analyzed with scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. For converting to SrCO₃ of celestite (SrSO₄) and to (NH₄)₂SO₄ of (NH₄)₂CO₃, a hydrometallurgical process optimization via the wet mechanochemical conversion using (NH₄)₂CO₃ was developed the first time in this work using response surface methodology. The wet mechanochemical conversion was carried out by varying ball to grinding material mass ratio, (NH₄)₂CO₃ to SrSO₄ mole ratio and the rotational speed of mill in a planetary mill. Under the optimum experimental conditions (9.24 of ball to grinding material mass ratio, 1.86 of (NH₄)₂CO₃ to SrSO₄ mole ratio and 400 rpm of the rotational speed of mill), the conversion of SrCO₃ was 99.08 pct. The (NH₄)₂SO₄ obtained as byproduct was crystallized.     

Aflatoxins in dairy cow feed,raw milk and milk products from Turkey

This study aims to detect aflatoxins (AFs) in dairy cow feed, milk and milk products using a high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) method. All the validation parameters met the method performance criteria of the European Union. The samples comprised 76 dairy cow feeds and 205 milk and milk products (including yoghurt and yoghurt-based beverage, ayran). AFs were present in 26.3% of the feed samples. Two feed samples exceeded the maximum limit (ML) of 5 µg kg^?1 for AFB₁ as established by the EU. Nineteen milk samples (21.1%) contained aflatoxin M₁ (AFM₁) of which three exceeded the EU ML of 0.05 µg l^?1. In addition, only two yoghurt samples and one ayran sample contained AFM₁, but the levels were lower than the EU ML.     

COx-free hydrogen production from ammonia decomposition over sepiolite-supported nickel catalysts

Sepiolite, a clay mineral, was utilized as a support for nickel-based catalysts for CO_x-free hydrogen production from ammonia decomposition. First, the physical and chemical properties of sepiolite were changed by calcining it at temperatures varying from 500 to 1000 °C, then nickel was impregnated on these calcined supports and tested for ammonia decomposition at various temperatures following reduction at 650 °C. Results indicated that even though the catalysts contained almost the same amount of nickel, they showed different hydrogen production performance. Detailed characterization of the catalysts before and after reaction illustrated that the support obtained by calcining sepiolite at 700 °C shows good basic properties with a high surface area offering a high degree of nickel dispersion. These properties lead to promising hydrogen production rates which are on par, if not higher, than most of the nickel-based catalysts prepared on supports, which are either not cheap or require tedious preparation procedures.     

Comparison of the efficacies of two different fiber post‐removal systems: A micro‐computed tomography study

The aim of this in vitro study was to compare the efficacies of two different fiber post‐removal systems. Thirty extracted single‐rooted mandibular premolar teeth were used. After RelyX fiber posts were cemented, the teeth were divided into two groups with regard to the post removal techniques: ultrasonic vibration and D.T. Light‐Post removal kit. Residual material, tooth volume changes, working time and micro‐crack formation were assessed using micro‐computed tomography. All data were analyzed using Wilcoxon signed‐rank and Mann–Whitney U tests. There was significantly more tooth root volume change in the ultrasonic group than removal kit group (p < .05). Fiber post removal time for the ultrasonic group was significantly longer than the removal kit group (p < .01).     

Paraoxonase 1-bound magnetic nanoparticles: preparation and characterizations

This is most probably the first time that covalently binding of Human serum paraoxonase 1 (PON1) to superparamagnetic magnetite nanoparticles via carbodiimide activation was investigated and presented in this study. PON1 was purified from human serum using ammonium sulfate precipitation and hydrophobic interaction chromatography (Sepharose 4B, L-tyrosine, 1-Napthylamine) and magnetic iron oxide nanoparticles were prepared by co-precipitation Fe(+2) and Fe(+3) ions in an ammonia solution at room temperature. X-ray diffraction (XRD) and the magnetic measurements showed that the nanoparticles are magnetite and superparamagnetic, respectively. Direct measurements by dynamic light scattering revealed that the hydrodynamic size was 16.76 nm with polydispersity index (PDI: 0.234). The analysis of Fourier transform infrared spectroscopy revealed that the PON1 was properly bound to magnetic nanoparticles replacing the characteristic band of -NH2 at 1629 cm(-1) with the protein characteristic band at 1744 cm(-1) and 1712 cm(-1). Magnetic measurements determined that PON1-bound nanoparticles have also favorable superparamagnetic properties with zero coercivity and remanence though a slightly smaller saturation magnetization due to the decrease of magnetic moment in the volume friction. The kinetic measurements indicated the PON1-bound nanoparticles retained 70% of its original activity and exhibited an improved stability than did the free enzyme. The PON1 enzyme is seen to be quite convenient to bind superparamagnetic nanoparticles as support material.     

Effects of drying process on antioxidant activity of purple carrots

Purple carrot was analysed for its antioxidant activity by measuring its scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. The amount of purple carrot necessary to decrease by 50% the initial DPPH concentration (EC50) was found 30.23 +/- 5.17 (mg sample/mg DPPH). Effects of the dehydration process on the antioxidant activity of purple carrots were also determined after dehydration by using tray drier and microwave+tray drier combination. Purple carrots were cleaned, washed, sorted, sliced, and blanched in water at 98 +/- 1 degree C for 2 min. Then half of the samples were dehydrated in microwave (45 min) and tray drier (105 min) combination, and others were dehydrated in tray drier (150 min) until reaching the constant weight. Raw, blanched and dehydrated purple carrots were compared for their antioxidant activity and total anthocyanin contents, color values (L*, a*, b*, C*, H degrees) and dry matter contents. The antioxidant activity as measured by DPPH, EC50 value ranged from 7.80 to 30.23 of processed and raw carrots where the H degrees values were changed from -3.68 to -23.96 corresponding to a bluish hue.     

In vivo biomodification of lipid-coated carbon nanotubes by Daphnia magna

This study examined the interactions between Daphnia magna and a water-soluble, lysophophatidylcholine coated single-walled carbon nanotube. D. magna were able to ingest the nanotubes through normal feeding behavior and utilize the lysophophatidylcholine coating as a food source. D. magna were able to modify the solubility of the nanotube, likely through digestion of the lipid coating. This study provides evidence of biomodification of a carbon-based nanomaterial by an aquatic organism. The modification significantly altered the physical properties of the nanomaterial in freshwater. Acute toxicity was observed only in the highest test concentrations. These are important findings related to determining the behavior and potential toxicity of coated nanomaterials released into the environment.