Controlled optical photonic crystal AND gate using nematic liquid crystal layers

Two optical AND gates built in 2D photonic crystal (PhC) platform have been proposed and numerically simulated using 2D finite element method (FEM). The suggested logic gates consist of five PhC waveguides and silicon annular ring resonator filled by nematic liquid crystal (NLC) of type E7. The first proposed AND gate can handle two inputs and support two operating wavelengths, λ = 1.5 and 1.55 µm. However, the second proposed AND gate can handle three inputs at λ = 1.5 µm. The reported logic gates offer high and low transmission levels with a threshold of 0.5 and an ultra-high bit rate of not less than 0.3 Tbits/s. Further, the suggested AND gates operation can be switched off by using the NLC layer.     

Design,Synthesis, and Antimicrobial Evaluation of Novel Thienopyrimidines and Triazolothienopyrimidines

2-Cyanoacetohydrazide and 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene derivatives were exploited as starting materials for the syntheses of novel thienopyrimidines and triazolothienopyrimidines. The proclivity of these compounds toward one-carbon donor reagents such as carbon disulfide, phenyl isothiocyanate, and aromatic aldehydes was investigated. The structures of all synthesized compounds were ascertained by spectral and analytical data. The antimicrobial activity of the target synthesized compounds was tested against various microorganisms.     

Regiocontrolled preparation of 3-acyl-6-aryl-2-pyridones via condensation of 3-aryl-3-chloropropeniminium salts with β-keto-amides

Α series of substituted 3-acyl-6-aryl-2-pyridones have been prepared in one-step reactions via condensation of 3-aryl-3-chloropropeniminium salts with β-keto-amides. This efficient synthesis has the advantages of high yields and simple reaction procedures.     

Investigation of neuroleptics and other aromatic compounds by laser-based ion mobility mass spectrometry

Laser-based ion mobility (IM) spectrometry was used for the detection of neuroleptics and PAH. A gas chromatograph was connected to the IM spectrometer in order to investigate compounds with low vapour pressure. The substances were ionized by resonant two-photon ionization at the wavelengths λ?=?213 and 266 nm and pulse energies between 50 and 300 μJ. Ion mobilities, linear ranges, limits of detection and response factors are reported. Limits of detection for the substances are in the range of 1–50 fmol. Additionally, the mechanism of laser ionization at atmospheric pressure was investigated. First, the primary product ions were determined by a laser-based time-of-flight mass spectrometer with effusive sample introduction. Then, a combination of a laser-based IM spectrometer and an ion trap mass spectrometer was developed and characterized to elucidate secondary ion–molecule reactions that can occur at atmospheric pressure. Some substances, namely naphthalene, anthracene, promazine and thioridazine, could be detected as primary ions (radical cations), while other substances, in particular acridine, phenothiazine and chlorprothixene, are detected as secondary ions (protonated molecules). The results are interpreted on the basis of quantum chemical calculations, and an ionization mechanism is proposed.     

Effect of solvent and structure on the kinetics and mechanism of the aquation of bromopentaamine cobalt(III) complex in binary aqueous mixtures

The kinetics of aquation of bromopentaamine cobalt(III) complex have been investigated spectrophotometrically in aqueous‐organic solvent media using acetonitrile, urea, and dimethyl sulfoxide as co‐solvents at 45 ≤ T (°C) ≤ 65. The logarithms of rate constant of the aquation reaction vary nonlinearly with the reciprocal of the dielectric constant for all cosolvent mixtures, indicating a specific solute–solvent interaction. Also, the rate constants are correlated with the total number of moles of water and the organic solvents. However, the solvent effects on the solvation components of the enthalpy of activation, ΔH^?, and the entropy of activation, ΔS^?, have been studied. Analysis of the solvent effect confirmed a common I_d mechanism for the aquation of the cobalt(III) complex. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36:494–499, 2004     

Characterization of volatile metabolites formed by molds on barley by mass and ion mobility spectrometry

The contamination of barley by molds on the field or in storage leads to the spoilage of grain and the production of mycotoxins, which causes major economic losses in malting facilities and breweries. Therefore, on‐site detection of hidden fungus contaminations in grain storages based on the detection of volatile marker compounds is of high interest. In this work, the volatile metabolites of 10 different fungus species are identified by gas chromatography (GC) combined with two complementary mass spectrometric methods, namely, electron impact (EI) and chemical ionization at atmospheric pressure (APCI)‐mass spectrometry (MS). The APCI source utilizes soft X‐radiation, which enables the selective protonation of the volatile metabolites largely without side reactions. Nearly 80 volatile or semivolatile compounds from different substance classes, namely, alcohols, aldehydes, ketones, carboxylic acids, esters, substituted aromatic compounds, alkenes, terpenes, oxidized terpenes, sesquiterpenes, and oxidized sesquiterpenes, could be identified. The profiles of volatile and semivolatile metabolites of the different fungus species are characteristic of them and allow their safe differentiation. The application of the same GC parameters and APCI source allows a simple method transfer from MS to ion mobility spectrometry (IMS), which permits on‐site analyses of grain stores. Characterization of IMS yields limits of detection very similar to those of APCI‐MS. Accordingly, more than 90% of the volatile metabolites found by APCI‐MS were also detected in IMS. In addition to different fungus genera, different species of one fungus genus could also be differentiated by GC‐IMS.     

A Silica Bilayer Supported on Ru(0001): Following the Crystalline‐to Vitreous Transformation in Real Time with Spectro‐microscopy

The crystalline‐to‐vitreous phase transformation of a SiO₂ bilayer supported on Ru(0001) was studied by time‐dependent LEED, local XPS, and DFT calculations. The silica bilayer system has parallels to 3D silica glass and can be used to understand the mechanism of the disorder transition. DFT simulations show that the formation of a Stone–Wales‐type of defect follows a complex mechanism, where the two layers show decoupled behavior in terms of chemical bond rearrangements. The calculated activation energy of the rate‐determining step for the formation of a Stone—Wales‐type of defect (4.3 eV) agrees with the experimental value. Charge transfer between SiO₂ bilayer and Ru(0001) support lowers the activation energy for breaking the Si?O bond compared to the unsupported film. Pre‐exponential factors obtained in UHV and in O₂ atmospheres differ significantly, suggesting that the interfacial ORu underneath the SiO₂ bilayer plays a role on how the disordering propagates within the film.     

Chemical constituents,Antibacterial and Acetylcholine esterase inhibitory activity of Cupressus macrocarpa leaves

Abstract

The chemical constituents of Cupressus macrocarpa were investigated. A new neolignan glycoside (1) in addition to nine known compounds were isolated. The acetylcholinesterase (AChE) inhibitory activity and antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) of different fractions and isolates of C. macrocarpa were evaluated. The light petroleum fraction showed the highest activity in both assays with IC₅₀ value of 88.79 µg/ml and 152.58 µg/ml for the AChE inhibitory activity and MRSA antibacterial activities, respectively. Weak to moderate activity were detected for the isolated compounds.     

Corrosion Inhibition Efficiency of Polytriethanolamine Surfactants for Pipe-Lines Carbon Steel in 1M HCl

Fifteen organic compounds were prepared from triethanolamine and its derivative. The triethanolamine was polymerized by condensation to get P₄, P₆, and P₈ at different molecular weight. The P8 was ethoxylated at different ethylene oxide units (en) (40, 100, and 120) to obtain three compounds (E(en)P₈). Every degree of ethoxylate was esterified with 1, 4, and 8 moles of oleic acid to get on 9 ethoxylated polytriethanolamine esters (E(en)P₈Om). The effect of adding these organic compounds on the electrochemical behavior of carbon steel in 1 M HCl was investigated by using the weight loss technique. The reported results in this study show that the addition of these surfactants inhibits the corrosion of carbon steel. The inhibition efficiency (I%) for each inhibitor increases with increasing the concentration. The maximum inhibition efficiency (95%) was obtained by (E(40)P₈O₁) at 600 ppm. The inhibitive efficiency was discussed on the light of chemical structure of the used inhibitors.     

Formylation of O-Silylated Enolates by Vilsmeier's Reagent

Reaction of trimethylsilylenol ethers and Vilsmeier's reagent leads to the corresponding regiocontrolled β-dicarbonyl compounds with high to good yields.