Synthesis and characterization of PMMA composites activated with starch for immobilization of L‐asparaginase

Poly (methyl methacrylate) (PMMA)–starch composites were prepared by emulsion polymerization technique for L‐asparaginase (L‐ASNase) immobilization as highly activated support. The hydroxide groups on the prepared composites offer a very simple, mild and firm combination for enzyme immobilization. The pure PMMA and PMMA‐starch composites were characterized as structural, thermal and morphological. PMMA‐starch composites were found to have better thermal stability and more hydrophilic character than pure PMMA. L‐ASNase was immobilized onto PMMA‐starch composites contained the different ratio of starch (1, 3, 5, and 10 wt %). Immobilized L‐ASNase showed better performance as compared to the native enzyme in terms of thermal stability and pH. K_m value of immobilized enzyme decreased approximately eightfold compared with the native enzyme. In addition to, immobilized L‐ASNase was found to retain 60% of activity after 1‐month storage period at 4 °C. Therefore, PMMA‐starch composites can be provided more advantageous in terms of enzymatic affinity, thermal, pH and storage stability as L‐ASNase immobilization matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43421.     

Comparison of the mechanical and biological properties of self-adhering materials

Purpose: The purpose of the present study was to compare the Vickers hardness numbers (VHNs), roughness numbers (RNs) and biological compatibility of glass carbomer (Glass Fill), resin-modified glass ionomer (Fuji II LC) and self-adhering flowable composite (Vertise Flow) materials. Materials and methods: Disc-shaped specimens of test materials (n = 15/group) were prepared, and VHNs and RNs were determined after 24 h. A direct contact test was used for cytotoxicity evaluation. Cell viability was measured for 24 h post-exposition with a photometric test (MTT assay; n = 16). Data were analysed using one-way analysis of variance with a post hoc Tukey’s test, the Kruskal–Wallis test and the Mann–Whitney U-test (p < 0.05). Results: Fuji II LC had the highest VHN. The VHN of Fuji II LC differed significantly from those of the other materials (p < 0.05). The RNs of Fuji II and Glass Fill were higher than that of Vertise Flow (p < 0.05). The self-adhering materials were not significantly cytotoxic compared with the control group (p > 0.05). Conclusions: The materials tested in this study showed a similar lack of cytotoxicity. The VHN of Fuji II LC was the highest, and the RN of Vertise Flow was the lowest.     

Photovoltaic solar cell properties of CdxZn1−xO films prepared by sol–gel method

Cd_xZn_1−xO films have been deposited by sol–gel spin-coating method onto glass substrates. The Cd/Zn ratio in solution was changed from 0 to 1. Zinc acetate dehydrates, cadmium acetate dehydrates, 2-methoxyethanol and monoethanolamine were used as a starting material (zinc and cadmium), solvent and stabilizer, respectively. The crystal structure and orientation of the films were investigated by X-ray diffraction (XRD) patterns. XRD patterns show that the films are polycrystalline nature. As x varies from 0 to 1, it was observed that the crystal structure changed from wurtzite (ZnO) to cubic (CdO) structure. The optical properties of these films have been investigated by means of the optical transmittance and reflectance spectra. A significant change in optical absorption edge, optical band gap and optical constant with variation in composition was observed.     

Activity and stability of TiO2 samples with different phase compositions in the decomposition of formaldehyde in SCW

TiO₂ samples with different crystal sizes and compositions were synthesized using a sol-gel method at different calcination temperatures (350–900 °C). The activity and stability of TiO₂ samples were determined by the gasification of formaldehyde in supercritical water (SCW) and by treatment in SCW. Increasing calcination temperature and SCW gasification (SCWG)/SCW treatment decreased the surface area of anatase TiO₂ samples due to growing crystallite size via agglomeration and sintering. Among anatase TiO₂ samples, the TiO₂ calcinated at 450 °C was found as the most suitable material under SCW conditions. However, the surface area of rutile TiO₂ slightly increased from 17.2 m² g^?1 to 19.8 m² g^?1 with the weakly crumbling of particles during SCWG. The highest hydrogen formation (63%) from formaldehyde in the SCW was obtained in the presence of anatase TiO₂ calcined at 350 °C and rutile TiO₂ calcined at 800 °C. CO₂ formation in the presence of anatase TiO₂ is higher than rutile TiO₂ because of the presence of active lattice oxygen species (O^?, O^2?) based on O₂-TPD.     

Study on the behavior of the trace metal and macro minerals in Mytilus galloprovincialis as a bioindicator species: the case of Marmara Sea, Turkey

Sea food is a major source of animal protein. Marine foods are very rich sources of mineral components. The total content of minerals in the raw flesh of marine fish and invertebrates is in the range of 0.6–1.5% wet weight. The contents of Na, K, Ca, Mg and P are up to 1 mg/100 g, whereas those of Fe, Zn, I are less than 1 mg/100 g. Mussels (Mytilus galloprovincialis) were investigated for macro and trace element composition throughout the year. Ranges of moisture, ash, protein and fat contents were 79.76–87.46 g/100 g, 1.06–2.06 g/100 g, 7.28–12.65 g/100 g and 0.33–3.49 g/100 g, respectively. While the highest protein and fat values were found in the summer (July–August), the highest moisture and ash contents were found in the winter (December–January). The contents of highest Na, K, Ca were found in the summer. Cadmium, lead and copper were found to be below the legislative limits throughout year. High levels of mercury were found in January and October. It should be discussed whether mussel may provide an alternative source of mineral for healthy nutrition.     

Study on the behavior of the trace metal and macro minerals in Mytilus galloprovincialis as a bioindicator species: the case of Marmara Sea, Turkey

Sea food is a major source of animal protein. Marine foods are very rich sources of mineral components. The total content of minerals in the raw flesh of marine fish and invertebrates is in the range of 0.6–1.5% wet weight. The contents of Na, K, Ca, Mg and P are up to 1 mg/100 g, whereas those of Fe, Zn, I are less than 1 mg/100 g. Mussels (Mytilus galloprovincialis) were investigated for macro and trace element composition throughout the year. Ranges of moisture, ash, protein and fat contents were 79.76–87.46 g/100 g, 1.06–2.06 g/100 g, 7.28–12.65 g/100 g and 0.33–3.49 g/100 g, respectively. While the highest protein and fat values were found in the summer (July–August), the highest moisture and ash contents were found in the winter (December–January). The contents of highest Na, K, Ca were found in the summer. Cadmium, lead and copper were found to be below the legislative limits throughout year. High levels of mercury were found in January and October. It should be discussed whether mussel may provide an alternative source of mineral for healthy nutrition.