Essential rosemary oil protects testicular cells against DNA-damaging effects of H2O2 and DMNQ

Rosemary oil (RO) is popular in the Mediterranean region as a culinary additive which has the ability to protect delicate organs such as liver, brain and heart. We examined the effect of RO consumption on resistance of rat testicular cells (TCs) against DNA-damaging effects of the oxidative agents H₂O₂ and DMNQ and on the activity of the antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). DNA lesions were detected by conventional and modified comet assay and the activities of GSH-Px and SOD were measured spectrophotometrically. Since TCs represent a mixture of haploid, diploid and tetraploid cells, we used flow cytometry for their differentiation and calculation of DNA-damaging effects of H₂O₂ and DMNQ in cells of different ploidy. The results showed that the oxidative DNA lesions were significantly reduced in TCs from rats administered RO; however, the activity of antioxidant enzymes did not differ in TCs from control and RO-supplemented rats.     

Electrostatic Adsorption of a Colloidal Sintering Agent on Silicon Nitride Particles

Pressureless sintering of silicon nitride requires addition of sintering agents. The main part of this study was done in order to homogenize the distribution of sintering agents, in this case Y₂O₃, in a silicon nitride matrix. Colloidal 10-nm Y₂O₃ Particles were electrostatically adsorbed on Si₃N₄ particle surfaces. The adsorption was studied by X-ray fluorescence analysis and electrophoretic measurements. Addition of Y₂O₃ sol to a Si₃N₄ suspension decreased the viscosity of the suspension. The slip casting properties of Si₃N₄ suspensions with added Y₂O₃ sol were examined, and the homogeneity of Y₂O₃ in the green compacts was compared with conventionally prepared samples. An improved microstructural homogeneity was obtained when Y₂O₃ sol particles were adsorbed on the Si₃N₄ particle surfaces.     

Collapse test and moment capacity of the Ruytenschildt reinforced concrete slab bridge

A large number of existing reinforced concrete solid slab bridges in the Netherlands are found to be insufficient for shear upon assessment. However, research has shown additional sources of capacity in slab bridges, increasing their total capacity and possibly changing their failure mode. Previous testing was limited to half-scale slab specimens cast in the laboratory. To study the full structural behaviour of slab bridges, testing to failure of a bridge is necessary. Research on load testing is carried out in order to develop load testing guidelines. In August 2014, a bridge was tested in two spans. The bridge was load tested, and additional cycles until yielding occurred in the reinforcement were added to the experiment. Though calculations with current design provisions showed that the bridge could fail in shear, the field test showed failure in flexure before shear. The unity check for flexure was determined. The experiment shows that the methods for rating of existing reinforced concrete slab bridges are conservative.     

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J. Wellington. (2000). Teaching and learning secondary science: Contemporary issues and practical approaches. London: Routledge. ISBN 0–4152–1403–3     

Production of Polyunsaturated Fatty Acids by Mortierella alpina Using Submerse and Solid State Fermentation

A new isolate of Mortierella alpina, > 98 % identical with M. alpina ATCC 16266, was cultivated in a defined glucose‐based medium with three organic nitrogen sources (glycine, urea and Na‐L‐glutamate) at three different concentrations in shaking flasks at 20 °C. The results were compared to the cultivation in complex medium with yeast extract as nitrogen source. In the defined media, high yields of polyunsaturated fatty acids (PUFAs) and arachidonic acid (ARA), respectively, were obtained with Na‐L‐glutamate. However, the absolute highest yields of PUFA and ARA were measured with the yeast extract medium. An optimized yeast extract complex medium was used for a submerse bioreactor cultivation in a 45‐L scale. Furthermore, M. alpina was cultivated in a solid state fermenter, using an oat bran water mixture as substrate.