Adsorption and conformation behavior of biotinylated fibronectin on streptavidin-modified TiO(X) surfaces studied by SPR and AFM

It is well-known that protein-modified implant surfaces such as TiO(2) show a higher bioconductivity. Fibronectin is a glycoprotein from the extracellular matrix (ECM) with a major role in cell adhesion. It can be applied on titanium oxide surfaces to accelerate implant integration. Not only the surface concentration but also the presentation of the protein plays an important role for the cellular response. We were able to show that TiO(X) surfaces modified with biotinylated fibronectin adsorbed on a streptavidin-silane self-assembly multilayer system are more effective regarding osteoblast adhesion than surfaces modified with nonspecifically bound fibronectin. The adsorption and conformation behavior of biotinylated and nonbiotinylated (native) fibronectin was studied by surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM). Imaging of the protein modification revealed that fibronectin adopts different conformations on nonmodified compared to streptavidin-modified TiO(X) surfaces. This conformational change of biotinylated fibronectin on the streptavidin monolayer delivers a fibronectin structure similar to the conformation inside the ECM and therefore explains the higher cell affinity for these surfaces.     

Fluorescent one-dimensional nanostructures from a group of uniform materials based on organic salts

Herein we report the synthesis of a fluorescent organic salt through anion exchange and the subsequent fabrication of 1D-nanostructures via a facile templating method.     

Maximum distance separable codes over {\mathbb{Z}_4} and {\mathbb{Z}_2 \times \mathbb{Z}_4}

Known upper bounds on the minimum distance of codes over rings are applied to the case of ${\mathbb Z_{2}\mathbb Z_{4}}$ -additive codes, that is subgroups of ${\mathbb Z_{2}^{\alpha}\mathbb Z_{4}^{\beta}}$ . Two kinds of maximum distance separable codes are studied. We determine all possible parameters of these codes and characterize the codes in certain cases. The main results are also valid when ?? = 0, namely for quaternary linear codes.     

A modified fractional least mean square algorithm for chaotic and nonstationary time series prediction

A method of modifying the architecture of fractional least mean square （FLMS） algorithm is presented to work with nonlinear time series prediction. Here we incorporate an adjustable gain parameter in the weight adaptation equation of the original FLMS algorithm and absorb the gamma function in the fractional step size parameter. This approach provides an interesting achievement in the performance of the filter in terms of handling the nonlinear problems with less computational burden by avoiding the evaluation of complex gamma function. We call this new algorithm as the modified fractional least mean square （MFLMS） algorithm. The predictive performance for the nonlinear Mackey glass chaotic time series is observed and evaluated using the classical LMS, FLMS, kernel LMS, and proposed MFLMS adaptive filters. The simulation results for the time series with and without noise confirm the superiority and improvement in the prediction capability of the proposed MFLMS predictor over its counterparts.     

An iterated-tabu-search heuristic for a variant of the partial set covering problem

In this paper, we propose a heuristic algorithm to solve a new variant of the partial set covering problem. In this variant, each element $e_i$ has a gain $g_i$ (i.e., a positive profit), each set $s_j$ has a cost $c_j$ (i.e., a negative profit), and each set $s_j$ is part of a unique group $G_k$ that has a fixed cost $f_k$ (i.e., a negative profit). The objective is to maximize profit and it is not necessary to cover all of the elements. We present an industrial application of the model and propose a hybrid heuristic algorithm to solve it; the proposed algorithm is an iterated-local-search algorithm that uses two levels of perturbations and a tabu-search heuristic. Whereas the first level of perturbation diversifies the search around the current local optimum, the second level of perturbation performs long jumps in the search space to help escape from local optima with large basins of attraction. The proposed algorithm is evaluated on thirty real-world problems and compared to a memetic algorithm. Computational results show that most of the solutions found by ITS are either optimal or very close to optimality.     

Thidiazuron-Induced Changes in Biomass Parameters,Total Phenolic Content,and Antioxidant Activity in Callus Cultures of Artemisia absinthium L.

Callus culture of Artemisia absinthium L. was established for enhanced production of phenolics and higher antioxidant activity. Callus was induced from seed-derived leaf explants, incubated on to MS media supplemented with thidiazuron (TDZ; 0.5–5.0 mg/l) either alone or in combination with α-naphthalene acetic acid (NAA; 1.0 mg/l). These callus cultures were investigated for their growth kinetics, total phenolic content, and antioxidant activity on weekly basis for a period of 49 days. Maximum dry biomass accumulation of 8.73 g/l was observed on day 42 in response to 1.0 mg/l TDZ and 1.0 mg/l NAA. Furthermore, maximum level of total phenolic content of 8.53 mg GAE/g DW and highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 72.6 % were observed in calli formed in response to 1.0 mg/l TDZ on day 42. The results showed a positive correlation of total phenolic content and DPPH radical scavenging activity in most of the callus cultures of A. absinthium L.     

Determination of naproxen in human plasma by GC–MS

This paper describes a GC–MS method for the determination of naproxen in human plasma. Naproxen and internal standard ibuprofen were extracted from plasma using a liquid–liquid extraction method. Derivatization was carried out using N‐methyl‐N‐(trimethylsilyl)trifluoroacetamide. The calibration curve was linear between the concentration range of 0.10–5.0 μg/mL. Intra‐ and interday precision values for naproxen in plasma were <5.14, and accuracy (relative error) was better than 4.67%. The extraction recoveries of naproxen from human plasma were between 93.0 and 98.9%. The LOD and LOQ of naproxen were 0.03 and 0.10 μg/mL, respectively. Also, this assay was applied to determine the pharmacokinetic parameters of naproxen in six healthy Turkish volunteers who had been given 220 mg naproxen.     

Gibberellic Acid Increases Secondary Metabolite Production in Echinacea purpurea Hairy Roots

Gibberellic acid (GA₃) is reported to have diverse effects on hairy root cultures of many plant species; therefore, the effects of GA₃ on the growth, secondary metabolite production (caffeic acid derivatives and lignin), phenylalanine ammonia lyase (PAL) activity, and free radical scavenging activity of light-grown Echinacea purpurea L. hairy roots were investigated. Eight concentrations of GA₃, ranging from 0.005 to 1.0 μM, were added to shake flask cultures. The moderate GA₃ concentration, 0.025 μM, resulted in the highest concentrations of cichoric acid, caftaric acid, and chlorogenic acid, as well as increased PAL activity, cell viability, and free radical scavenging activity, while higher and lower GA₃ concentrations resulted in reduced levels compared to the control (lacking GA₃). The moderate GA₃ concentration also affected root morphogenesis; supplementation with 0.025 μM GA₃ resulted in the development of thick, dense, purple-colored roots, while roots exposed to the higher and lower concentrations of GA₃ were thin and off-white. This study demonstrates that supplementation with GA₃ may be an excellent strategy to optimize the production of secondary metabolites from E. purpurea hairy root cultures; however, the GA₃ concentration is a critical factor.     

Synthesis,characterization and impregnation of lead sulphide semiconductor nanoparticles on polymer matrix

Lead sulphide nanoparticles were prepared using a precursor and dual sources methods. The composites were fabricated by stabilizing chemically synthesized semiconductor PbS nanocrystals into laurylmethacrylate and ethyleneglycol dimethacrylate matrix in the presence of tri-n-octylphosphine. PbS nanocrystals were dispersed in toluene as a compatible medium for the polymerization and cross-linking of poly laurylmethacrylate networks. The nano-sized particles and polymer composites were characterized by XRD and TEM. Possible formulations and incorporation of these PbS nanoparticles in polymer matrix have been discussed. The reported lead sulphide nanoparticles into tailered polymeric system show greater uniformity and stability.