Half-metallic silicon nanowires: first-principles calculations

From first-principles calculations, we predict that specific transition metal (TM) atom-adsorbed silicon nanowires have a half-metallic ground state. They are insulators for one spin direction, but show metallic properties for the opposite spin direction. At high coverage of TM atoms, ferromagnetic silicon nanowires become metallic for both spin directions with high magnetic moment and may have also significant spin polarization at the Fermi level. The spin-dependent electronic properties can be engineered by changing the type of adsorbed TM atoms, as well as the diameter of the nanowire. Present results are not only of scientific interest, but also can initiate new research on spintronic applications of silicon nanowires.     

Synthesis and characterization of multiarm (Benzoin-PS)m-polyDVB star polymer as a polymeric photoinitiator for polymerization of acrylates and methacrylates

In this study, a new benzoin-based multi-arm star polymer was synthesized by using ATRP, and characterization was achieved by spectrophotometric and chromatographic methods. Obtained multiarm (Benzoin-PS)_m-polyDVB star polymer was employed as a polymeric photoinitiator for polymerization of methacrylates and acrylates. Photophysical properties of this initiator were determined by fluorescence and phosphorescence measurements, the phosphorescence lifetime was calculated as 29 ms hence the lowest triplet state nature was n-π* character, and laser flash photolysis technique was additionally used to get more information about triplet state and triplet lifetime which was calculated as 1.34 ms. Photokinetics of difunctional acrylate such as HDDA was studied with a multi-arm (Benzoin-PS)_m-polyDVB star polymeric initiator using Photo-DSC.     

Signals in asbestos related diseases in human breath - preliminary results

Several diseases occur due to asbestos exposure. Until today, asbestos predicted mortality and morbidity will increase because of the long latency period. Actually, the methods to investigate asbestos related disease are mostly invasive. Therefore, the aim of the present paper was to investigate, whether signals in human breath could be correlated to Asbestos related lung diseases using a multi-capillary column (MCC) connected to an ion mobility spectrometer (IMS) as non-invasive method. Here, the breath samples of 10 mL of 25 patients suffering from asbestos related diseases. This group includes patients with asbestos related pleural thickening with and without pulmonary fibrosis. Twelve healthy persons constitute the control group and the breath samples are compared with those of the BK4103 patients. In total 83 peaks are found in the IMS-Chromatogram. A discrimination was possible with p-values <0.001 for two peaks (99.9 %), <0.01 (99 %) for 5 peaks and <0.05 (95 %) for 17 peaks. The most discrimination peaks alpha pinene and 4-ethyltoluol were identified among some others with lower p-values. The corresponding Box-and-Whisker-Plots comparing both groups are presented. In addition, a decision tree including all peaks was created that shows a differentiation with alpha pinene between BK4103 (pleural plaques group) and the control group. In addition, the sensitivity was calculated to 96 %, specificity was 50 %, positive and negative predictive values were 80 % and 86 %. Ion mobility spectrometry was introduced as non-invasive method to separate both groups Asbestos related and healthy. Naturally, the findings need further confirmation on larger population groups, but encourage further investigations, too.     

Analysis of enzymopathies in the human red blood cells by constraint-based stoichiometric modeling approaches

The human red blood cell (RBC) metabolism is investigated by calculating steady state fluxes using constraint-based stoichiometric modeling approaches. For the normal RBC metabolism, flux balance analysis (FBA) is performed via optimization of various alternative objective functions, and the maximization of production of ATP and NADPH is found to be the primary objective of the RBC metabolism. FBA and two novel approaches, minimization of metabolic adjustment (MOMA) and regulatory on-off minimization (ROOM), which can describe the behavior of the metabolic networks in case of enzymopathies, are applied to observe the relative changes in the flux distribution of the deficient network. The deficiencies in several enzymes in RBC metabolism are investigated and the flux distributions are compared with the non-deficient FBA distribution to elucidate the metabolic changes in response to enzymopathies. It is found that the metabolism is mostly affected by the glucose-6-phosphate dehydrogenase (G6PDH) and phosphoglycerate kinase (PGK) enzymopathies, whereas the effects of the deficiency in DPGM on the metabolism are negligible. These stoichiometric modeling results are found to be in accordance with the experimental findings in the literature related to metabolic behavior of the human red blood cells, showing that human RBC metabolism can be modeled stoichiometrically.     

Synthesis of HAP coating on galvanostatically treated stainless steel substrates by sol–gel method

Producing bioactive hydroxyapatite coatings on metallic implant materials combines the mechanical advantages of implant materials and biological affinity of the hydroxyapatite surface to the natural tissue. In this work, hydroxyapatite was synthesized on 316L stainless steel substrates via sol–gel method by using Ca(NO₃)₂·4H₂O and C₆H₁₅O₃P. In order to improve adherence of the coatings produced, the surface of the substrate was initially modified by electrodepositing nucleus of calcium phosphate compounds. Effect of aging time for preparation of the sol solution and coating characteristics were investigated. The phase compositions and structures of the coatings were characterized by X-ray diffractometry, and scanning electron microscopy was used to determine morphological characteristics of the coatings. Adhesion between the hydroxyapatite coating and the substrate was investigated by using scanning scratch tester. The coating produced on the modified surface by the sol solution aged for 24 h was found to prove better morphological and adhesion properties.     

Radar Cross Section (RCS) Modeling and Simulation, Part 2: A Novel FDTD-Based RCS Prediction Virtual Tool for the Resonance Regime

A novel FDTD-based virtual radar cross section (RCS) prediction tool is introduced. Characteristic examples using simple three-dimensional structures, as well as more-realistic complex air and surface targets, are presented. The virtual tool automatically constructs a wire-grid model of the structure under investigation. It is therefore also possible to compare FDTD results against MoM-based NEC (Numerical Electromagnetics Code) data. It is shown that this virtual tool can be used for both educational and research purposes.     

Various brush polymers through ring opening metathesis polymerization and nitroxide radical coupling reaction

A 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO)‐terminated poly(ethylene glycol) (PEG) or ‐poly(ε‐caprolactone) (PCL) (PEG₁₁‐TEMPO or PCL₂₃‐TEMPO) is grafted as a side chain onto a ROMP‐generated polyoxanorbornene (PONB) main backbone with bromide pendant groups (PONB₂₀‐Br) using the NRC click reaction to yield related the brush copolymers, PONB₂₀‐g‐PEG₁₁ or PONB₂₀‐g‐PCL₂₃ catalyzed by Cu(I), Cu(0), and N,N,N′,N″,N″‐pentamethyldiethylenetriamine in N,N‐dimethylformamide at room temperature. Additionally, a ROMP‐generated brush copolymer PONB₉‐g‐poly(methyl methacrylate)₂₄ (PMMA)₂₄‐Cl was reacted with a PEG₁₁‐TEMPO or a PCL₂₃‐TEMPO precursor via the NRC click reaction to yield a corresponding brush terpolymer, PONB₉‐g‐(PMMA₂₄‐b‐PEG₁₁) or PONB₉‐g‐(PMMA₂₄‐b‐PCL₂₃) under a similar reaction condition described above. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Novel Transimpedance Type First-Order All-Pass Filter Using Single Otra

A novel transimpedance-mode first-order all-pass filter configuration is proposed. It uses a single operational transresistance amplifier (OTRA) and few passive components. The proposed circuit is structurally all-pass that does not impose any component matching condition. The proposed circuit is insensitive to parasitic input capacitances and input resistances due to the internally grounded input terminals of the OTRA. It provides an alternative realization of phase equalizers for analog signal processing applications by providing also current-to-voltage conversion. The theoretical results are verified with PSPICE simulations using a CMOS realization of OTRA.