Structural,Optical and Electrochromic Properties of WO_3 Thin Films Prepared by Chemical Spray Pyrolysis Versus Spin Coating Technique

In this study, Tungsten Oxide (WO₃) thin films were prepared by Chemical Spray Pyrolysis (CSP) and Spin Coating (SC) techniques and it was investigated effects of technique and parameter on the films. WO₃ thin films were deposited on ITO (Indium Tin Oxide) coated glasses. The structural, optical and electrochromic properties of the WO₃ thin films were characterized by XRD, SEM, UV, and CV measurements. The sharpest (200) peak was observed in the XRD spectra and optical band gaps were calculated around 2.6～3.1 eV via UV-Vis spectra for all of the samples. Micro fibrous reticulated surface (filamentous like) morphology for the films deposited by CSP technique and smooth surface morphology with high optical transmittance for the film deposited by SC Technique were obtained from SEM images. In addition to these results, it was revealed that all the samples exhibit good electrochromic performance.     

Hybrids of amino acids and acetylenic DNA-photocleavers: optimising efficiency and selectivity for cancer phototherapy

Hybrid agents which combine potent DNA-photocleavers with tunable amino acids or small peptides were designed to improve selectivity of Nature's most potent class of antibiotics towards cancer cells. The ability of these compounds to photocleave DNA is controlled by their incorporation into hybrid architectures with functional elements derived from natural amino acids. These conjugates are highly effective at inducing double-strand DNA cleavage and, in some cases, rival or even surpass both naturally occurring DNA cleavers and anticancer agents that are currently in clinical use. The possibility of triggering their activity in a photochemical and pH-sensitive fashion allows for a high degree of selectivity over activation. The conjugates were shown to penetrate cell membranes and induce efficient intracellular DNA cleavage. Initial in vitro tests against a variety of cancer cell lines confirm the potential of these compounds as anticancer agents at low nanomolar concentrations.     

Step size strategies for the numerical integration of systems of differential equations

In this study, the step size strategies are obtained such that the local error is smaller than the desired error level in the numerical integration of a type of nonlinear equation system in interval [_t0,T]$[t_0,T]$. The algorithms are given for calculating step sizes and numerical solutions according to these strategies. The algorithms are supported by the numerical examples.     

The stabilities, electronic structures and elastic properties of Rb-As systems

The structural, electronic and elastic properties of Rb–As systems (RbAs in NaP, LiAs and AuCu structures, RbAs2 in the MgCu2 structure, Rb3 As in Na3As, Cu3 P and Li3Bi structures, and Rb5 As4 in the A5B4 structure) are investigated with the generalized gradient approximation in the frame of density functional theory. The lattice parameters, cohesive energies, formation energies, bulk moduli and the first derivatives of the bulk moduli (to fit Murnaghan’s equation of state) of the considered structures are calculated and reasonable agreement is obtained. In addition, the phase transition pressures are also predicted. The electronic band structures, the partial densities of states corresponding to the band structures and the charge density distributions are presented and analysed. The second-order elastic constants based on the stress-strain method and other related quantities such as Young’s modulus, the shear modulus, Poisson’s ratio, sound velocities, the Debye temperature and shear anisotropy factors are also estimated.     

Fractional optimal control of a 2-dimensional distributed system using eigenfunctions

This paper presents an eigenfunctions expansion based scheme for Fractional Optimal Control (FOC) of a 2-dimensional distributed system. The fractional derivative is defined in the Riemann–Liouville sense. The performance index of a FOC problem is considered as a function of both state and control variables, and the dynamic constraints are expressed by a Partial Fractional Differential Equation (PFDE) containing two space parameters and one time parameter. Eigenfunctions are used to eliminate the terms containing space parameters and to define the problem in terms of a set of generalized state and control variables. For numerical computation Grünwald–Letnikov approximation is used. A direct numerical technique is proposed to obtain the state and the control variables. For a linear case, the numerical technique results into a set of algebraic equations which can be solved using a direct or an iterative scheme. The problem is solved for different number of eigenfunctions and time discretization. Numerical results show that only a few eigenfunctions are sufficient to obtain good results, and the solutions converge as the size of the time step is reduced.     

The effect of pressure on the elastic constants of Cu, Ag and Au: a molecular dynamics study

This paper describes the effect of pressure on some the mechanical properties of transition metals Cu, Ag, and Au, such as elastic constants and bulk modulus. Using molecular dynamics (MD) simulation, the present study was carried out using the modified many-body Morse potential function expression in the framework of the Embedded Atom Method (EAM). The effect of pressure on equilibrium volume, elastic constants, and bulk modulus were determined, and found to be in agreement with other theoretical calculations and experimental data.     

Polymerization of monoisocyanates by the Pruitt–Baggett adduct

n-Butyl isocyanate (nBIC) was polymerized in bulk by the Pruitt–Baggett adduct (PBA) at ?23, 0.0, and 25.0°C. Polymerization was accompanied by trimerization to the cyclicisocyanurates at all temperatures. Spectroscopic evidences supported the nylon-1 structure for both trimer and polymer. The polymer/trimer ratio and the molecular weight of produced polymers were found to increase with decreasing temperature. The Pruitt–Baggett catalyst (PBC), which is the reaction product of (PBA + H₂O) system, also polymerized nBIC, but with a relatively slower rate. In aromatic and etheric solutions, nBIC was only trimerized by PBA. Copolymerization of nBIC with propylene oxide by PBA and PBC failed. Some selected monoisocyanates were also polymerized by PBA. © 1993 John Wiley & Sons, Inc.     

3-Aminoquinazoline–phosphine ligands and their ruthenium(II) complexes: application in catalytic hydrogenation and transfer hydrogenation reactions

3-Aminoquinazolinone–phosphine proligands (5a–e) and their Ru(II) complexes (6a–e) were prepared and characterized by NMR (¹H, ¹³C, ³¹P{¹H}), FTIR and microanalysis. The 3-aminoquinazolinone–phosphine ligands were found to coordinate with the Ru(II) center via their phosphorus and nitrogen atoms. The Ru(II) complexes were applied as catalysts for the hydrogenation and transfer hydrogenation of prochiral ketones. The results showed that these complexes are efficient transfer hydrogenation catalysts.     

Comparative Studies on Essential Oil and Phenolic Content with In Vitro Antioxidant,Anticholinesterase, Antimicrobial Activities of Achillea biebersteinii Afan. and A. millefolium subsp. millefolium Afan. L. Growing in Eastern Turkey

The potential applications of Achillea species in various industries have encouraged the examination of their phytochemical components along with their biological potential. In the present study, phenolic contents and essential oil compositions together with the in vitro biological activities of the aerial parts from Achillea biebersteinii Afan. and Achillea millefolium subsp. millefolium Afan. collected from Turkey were evaluated. Different solvent extracts (n-hexane, chloroform, methanol, water) were prepared and their antimicrobial, anticholinesterase, and antioxidant activities were studied. The LC-MS/MS results revealed the presence of 16 different phenolic compounds, including chlorogenic acid, rutin, quercetin, and luteolin glycosides, in methanolic extracts. According to GC-FID and GC/MS results, the primary components of the oils were identified as 1,8-cineole (32.5%), piperitone (14.4%), and camphor (13.7%) in A. biebersteinii and 1,8-cineole (12.3%) and β-eudesmol (8.9%) in A. millefolium subsp. millefolium. The infusion and methanolic extracts of both species were found to be rich in their total phenolic content as well as their antioxidant and anticholinesterase activity. In contrast, the n-hexane and chloroform extracts of both species showed strong antimicrobial activity with MIC values ranging from 15 to 2000 μg/mL. Our findings suggest that the investigated Achillea species could be evaluated as potent natural agents, and further studies into the promising extracts are needed.     

Palladium(II) complexes with aminomethylphosphine ligands as catalysts for the heck reaction

New, aminomethyldiphosphine (P C N) ligands, ((C₆H₅)₂PCH₂)₂NR (R =  C₆H₃ (CH₃)(OH) ( 1a ),  C₆H₄OC₆H₅( 1b ),  C₆H₄SC₆H₅) ( 1c )) and their Pd(II) complexes have been synthesized and characterized. These complexes were found to be efficient catalysts in the Heck reaction of activated and deactivated aryl halide with a variety of olefins. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:466–471, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21038