Electrodeposition of platinum on polytyramine-modified electrodes for electrocatalytic applications

Cyclic voltammetry was used in order to deposit conducting polytyramine (PTy) on graphite substrates. In acidic media, ca. 40 deposition cycles resulted in the formation of stable polymer films with reasonably good resistivity. Electrochemical deposition of platinum on the PTy-covered graphite substrate allowed us to obtain a composite material that exhibits, for a platinum loading of 0.34 mg cm⁻², a specific electrochemically active surface area of the Pt particles of ca. 57 m² g⁻¹. Good electrocatalytic activity of this electrode material for phenol oxidation in acidic media was found, and the results suggested that, when deposited as small particles in a PTy matrix, platinum is less sensitive to deactivation by phenol oxidation polymeric products.     

Color‐emotion associations and color preferences: A case study for residences

This study examines existing beliefs about “color” focusing on color‐emotion associations by discussing how color can be used as a way of communicator to fulfill human needs in residences. Fifty people from various age groups participated in the study. They were asked to match a list of adjectives with the proper color samples from the catalogue of a quite popular color producer firm in Turkey. Results indicate that there is a strong dependency between the choice and use of green at residences. Emotional responses to colors change with value and saturation levels. According to the test results, gender and age are determining factors in the selection of achromatic black. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 144 – 150, 2007     

Robust guaranteed cost state estimation for discrete‐time systems with random delays and random uncertainties

This paper investigates the guaranteed cost state estimation problem for a class of discrete‐time systems based on the Wirtinger‐based inequality with randomly occurring delays (RODs) and randomly occurring uncertainties (ROUs). The time‐varying delays and parameter uncertainties are considered to occur in random way. Certain mutually uncorrelated Bernoulli‐distributed white‐noise sequences are included to govern the random occurrences. The cost function is chosen appropriately to guarantee an adequate level of performance. New sufficient conditions are established in terms of linear matrix inequalities to ensure the estimation of state vectors for the given discrete‐time system by constructing Lyapunov‐Krasovskii functionals and using reciprocally convex lemma. The advantage of using the proposed results is illustrated via numerical examples.     

Tissue engineering approach to repair abdominal wall defects using cell-seeded bovine tunica vaginalis in a rabbit model

The aim of this study was to engineer skeletal muscle tissue for repair abdominal wall defects. Myoblast were seeded onto the scaffolds and cultivated in vitro for 5 days. Full thickness abdominal wall defects (3 × 4 cm) were created in 18 male New Zealand white rabbits and randomly divided into two equal groups. The defects of the first group were repaired with myoblast-seeded-bovine tunica vaginalis whereas the second group repaired with non-seeded-bovine tunica vaginalis and function as a control. Three animals were sacrificed at 7th, 14th, and 30th days of post-implantation from each group and the explanted specimens were subjected to macroscopic and microscopic analysis. In every case, seeded scaffolds have better deposition of newly formed collagen with neo-vascularisation than control group. Interestingly, multinucleated myotubes and myofibers were only detected in cell-seeded group. This study demonstrated that myoblast-seeded-bovine tunica vaginalis can be used as an effective scaffold to repair severe and large abdominal wall defects with regeneration of skeletal muscle tissue.     

Over-expression of the X-linked inhibitor of apoptosis protein (XIAP) delays serum deprivation-induced apoptosis in CHO-K1 cells

Serum deprivation inhibits cell growth and initiates apoptosis cell death in mammalian cell cultures. Since apoptosis is a genetically controlled cell death pathway, over-expression of anti-apoptotic proteins may provide a way to delay apoptosis. This study investigated the ability of the X-linked inhibitor of apoptosis protein (XIAP) to inhibit apoptosis induced by serum deprivation. Study includes evaluation of the ability of XIAP to prolong culture period and its effect on cell proliferation in serum-deprived media. The full length human XIAP was introduced into CHO-K1 cell lines and the effects of XIAP over-expression on the inhibition of apoptosis induced by serum-deprived conditions were examined. In batch cultures, cells over-expressing XIAP showed decreased levels of apoptosis and a higher number of viable cell under serum-deprived conditions compared to the control cell lines. The viability of control cells dropped to 40% after 2 days of serum deprivation, the XIAP expressing cells still maintained at a viability higher than 90%. Further investigation revealed that the caspase-3 activity of the CHO-K1 cell line was inhibited as a result of XIAP expression.     

Ultrasonication‐assisted synthesis of molecularly imprinted polymer‐encapsulated magnetic nanoparticles for rapid and selective removal of 17β‐estradiol from aqueous environment

Molecularly imprinting technique was combined with magnetic nanoparticles to synthesize molecularly imprinted polymer‐encapsulated particles for selective removal and efficient separation of estrogenic compounds from water. The core‐shell‐structured particles were successfully prepared by a novel 2‐h ultrasonication‐assisted synthesis in a mixture of water and organic solvent using dual‐layer surfactant‐modified magnetic particles as core, the most physiologically active estrogenic compound (17β‐estradiol) as template, and widely adapted methacrylic acid as functional monomer. Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and magnetic separation were used to characterize the particles. High‐performance liquid chromatography–tandem mass spectrometry was used for quantitative binding performance analysis at low‐nanogram per milliliter levels. The particles exhibited satisfactory recognition of 17β‐estradiol in water. They possessed great potential for rapid, cost‐effective, and efficient separation of estrogenic compounds from aqueous environment with specificity. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Physicochemical Characterization of Whole Egg Powder Microencapsulated by Spray Drying

Physical characterization and oxidative stability of egg powder microencapsulated by spray drying were studied in this work. The wall material (gelatin, lactose, pullulan, and their mixtures) and liquid egg mixtures were prepared by homogenization at 22,000 rpm for 60 s. The spray drying was carried out at pilot-scale spray dryer (Niro Mobile Minor, Søborg, Denmark). The spray-dried egg powders were analyzed for moisture content, water activity, peroxide value, total cholesterol oxidation products (TCOPs), particle properties, and bulk properties. Using gelatin as wall material resulted in a significant increase in the moisture content and water activity of egg powder during storage and it improved flowability. Egg powders containing pullulan as wall material showed a fibrous structure and had the lowest bulk density. Adding lactose as wall material increased the oxidative stability, which was indicated with lowest peroxide value and TCOPs level of egg powder.     

Screening of Molecular Virulence Markers in Staphylococcus aureus and Pseudomonas aeruginosa Strains Isolated from Clinical Infections

Staphylococcus (S.) aureus and Pseudomonas (Ps.) aeruginosa are two of the most frequently opportunistic pathogens isolated in nosocomial infections, responsible for severe infections in immunocompromised hosts. The frequent emergence of antibiotic-resistant S. aureus and Ps. aeruginosa strains has determined the development of new strategies in order to elucidate the different mechanisms used by these bacteria at different stages of the infectious process, providing the scientists with new procedures for preventing, or at least improving, the control of S. aureus and Ps. aeruginosa infections. The purpose of this study was to characterize the molecular markers of virulence in S. aureus and Ps. aeruginosa strains isolated from different clinical specimens. We used multiplex and uniplex PCR assays to detect the genes encoding different cell-wall associated and extracellular virulence factors, in order to evaluate potential associations between the presence of putative virulence genes and the outcome of infections caused by these bacteria. Our results demonstrate that all the studied S. aureus and Ps. aeruginosa strains synthesize the majority of the investigated virulence determinants, probably responsible for different types of infections.