Green and Facile Synthesis of New 3-(Phenylallylideneamino)indeno[1,2-d]imidazoles

A green and facile strategy has been proposed for the synthesis of previously unknown 3a,8a-dihydroxy-3-[(3-phenylprop-2-en-1-ylidene)amino]-2-sulfanylidene-2,3,3a,8a-tetrahydro-1H-indeno[1,2-{und}]imidazol-8-one and 3a,8a-dihydroxy-3-[(3-phenylprop-2-en-1-ylidene)amino]-1,3,3a,8a-tetrahydroindeno[1,2-d]-imidazole-2,8-dione in excellent yields by condensation of cinnamaldehyde thiosemicarbazone and semicarbazone, respectively, with ninhydrin in boiling dioxane. The reaction is clean, simple, and free of work-up and column chromatography.

     

Fluorescence decay of singlet excited-state of safranine T and its interaction with ground-state of pyridinthiones in micelles and homogeneous media

The fluorescence decays of safranine T were studied in different homogeneous solvents and heterogeneous micellar solutions. It has been found that micellization leads to an increase in the lifetime. The lifetime distributions were studied in micelles and homogeneous media. It was found that the different half-width distributions of the dye in different micelles are related to the different orientation of the dye in different micelles. Also, the fluorescence quenching of safranine T by 4,6-disubstituted-3-cyanopyridin-2(1H)-thiones was studied in chloroform, methanol and acetonitrile as well as in different micelles. In heterogeneous media the kq values for quenching of safranine T by thiones in various micelles increase on the following order: kq(CTAB) < kq(TX-100) < kq(SDS). This is due to the electrostatic interactions between the anionic SDS and the cationic moiety of safranine T and therefore the quenching process will be less significant.     

In Vivo Investigation of the Ameliorating Effect of Tempol against MIA-Induced Knee Osteoarthritis in Rats: Involvement of TGF-β1/SMAD3/NOX4 Cue

Osteoarthritis (OA) is a complex disease characterized by structural, functional, and metabolic deteriorations of the whole joint and periarticular tissues. In the current study, we aimed to investigate the possible effects of tempol on knee OA induced by the chemical chondrotoxic monosodium iodoacetate (MIA) which closely mimics both the pain and structural changes associated with human OA. Rats were administrated oral tempol (100 mg/kg) one week post-MIA injection (3 mg/50 μL saline) at the right knee joints for 21 consecutive days. Tempol improved motor performance and debilitated the MIA-related radiological and histological alterations. Moreover, it subsided the knee joint swelling. Tempol decreased the cartilage degradation-related biomarkers as matrix metalloproteinase-13, bone alkaline phosphatase (bone ALP), and fibulin-3. The superoxide dismutase mimetic effect of tempol was accompanied by decreased NADPH oxidase 4 (NOX4), inflammatory mediators, nuclear factor-kappa B (NF-κB), over-released transforming growth factor-β1 (TGF-β1). Tempol decreased the expression of chemokine (C-C motif) ligand 2 (CCL2). On the molecular level, tempol reduced the phosphorylated protein levels of p38 mitogen-activated protein kinase (MAPK), and small mother against decapentaplegic 3 homologs (SMAD3). These findings suggest the promising role of tempol in ameliorating MIA-induced knee OA in rats via collateral suppression of the catabolic signaling cascades including TGF-β1/SMAD3/NOX4, and NOX4/p38MAPK/NF-κB and therefore modulation of oxidative stress, catabolic inflammatory cascades, chondrocyte metabolic homeostasis.     

Polymeric herbicide–Montmorillonite composite: synthesis,characterization and release studies

The production of polymeric herbicide intercalated onto montmorillonite interlayer through the process of cation exchange, in order to produce chemically bound polymeric herbicide with clay, has been reported. This was carried out by cation exchange of clay with onium salts of preformed polymeric pentachlorophenyl methacrylate. The products were characterized by various techniques including IR spectroscopy and elemental microanalysis. The interlayer spacing was determined by X‐ray diffraction and thermogravimetric analysis (TGA) and calcination investigated the thermal stability. The morphology of the composite was investigated by scanning electron microscopy. The swelling behaviors in different solvents and release of pentachlorophenol (PCP) in different medium have been described. Copyright © 2001 John Wiley & Sons, Ltd.     

Streamwise evolution of a high-Schmidt-number passive scalar in a turbulent plane wake

The concentration fluctuation c of diluted fluorescein dye, a high-Schmidt-number passive scalar (Sc=ν/D ≈ 2000, ν and D are the fluid momentum and dye diffusivities, respectively), is measured in the wake of a circular cylinder using a single-point laser-induced fluorescence (SPLIF) technique. The streamwise decay rate of the mean and rms values of c is slow in comparison to that of θ, the temperature fluctuation for which the molecular Prandtl number Pr=ν/κ is about 0.7 (κ is the thermal diffusivity). The comparison between mean and rms distributions of c and θ highlights the combined role the Reynolds and Schmidt numbers play in terms of dispersing the scalar. The streamwise evolution of the probability density functions (pdfs) of c and θ suggest that while p(θ) is approximately Gaussian in the intermediate wake (x/d ≈ 80), p(c) is strongly non-Gaussian, and depends on both x/d and Re. The skewness of c is larger than that of θ along the wake centreline. Arguably, the asymmetry of p(c) reflects the relatively strong organisation of the large-scale motion in the far-wake. Received: 27 July 2000/Accepted: 22 December 2000     

CH(A2Delta) Formation in hydrocarbon combustion: the temperature dependence of the rate constant of the reaction C2H + O2--> CH(A2Delta) + CO2

The temperature dependence of the rate constant of the chemiluminescence reaction C2H + O2 --> CH(A) + CO2, k1e, has been experimentally determined over the temperature range 316-837 K using pulsed laser photolysis techniques. The rate constant was found to have a pronounced positive temperature dependence given by k1e(T) = AT(4.4) exp(1150 +/- 150/T), where A = 1 x 10(-27) cm(3) s(-1). The preexponential factor for k1e, A, which is known only to within an order of magnitude, is based on a revised expression for the rate constant for the C2H + O(3P) --> CH(A) + CO reaction, k2b, of (1.0 +/- 0.5) x 10(-11) exp(-230 K/T) cm3 s(-1) [Devriendt, K.; Van Look, H.; Ceursters, B.; Peeters, J. Chem. Phys. Lett. 1996, 261, 450] and a k2b/k1e determination of this work of 1200 +/- 500 at 295 K. Using the temperature dependence of the rate constant k1e(T)/k1e(300 K), which is much more accurately and precisely determined than is A, we predict an increase in k(1e) of a factor 60 +/- 16 between 300 and 1500 K. The ratio of rate constants k2b/k1e is predicted to change from 1200 +/- 500 at 295 K to 40 +/- 25 at 1500 K. These results suggest that the reaction C2H + O2 --> CH(A) + CO2 contributes significantly to CH(A-->X) chemiluminescence in hot flames and especially under fuel-lean conditions where it probably dominates the reaction C2H + O(3P) --> CH(A) + CO.     

Radiation synthesis of copper sulphide/poly(vinyl alcohol) nanocomposites films: an efficient and reusable catalyst for p-nitrophenol reduction

ABSTRACT

Copper sulphide nanoparticles (CuS NPs) were in situ synthesised via irradiation process, using Poly (vinyl alcohol) (PVA) as host polymeric matrices. The as-prepared CuS/PVA nanocomposite films were characterised by X-ray diffraction (XRD) spectroscopy, ultraviolet-visible (UV-VIS) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Both UV-VIS spectra and X-ray diffraction patterns confirmed the formation of CuS nanoparticles. The FTIR spectrum indicates the coordination between CuS nanoparticles and the OH groups of the PVA chains. The TEM image showed that the obtained CuS nanoparticles have spherical shape, monodispersed and uniform particle size distribution. The CuS/PVA nanocomposite film was successfully applied in the reduction of p-nitrophenol into p-aminophenol as a catalyst using NaBH₄ as reducing agent. The catalytic test indicates that CuS/PVA nanocomposite film has high activity for the conversion of P-NP into P-AP and effectively recycled and reused for several times.     

Gray Codes,Loopless Algorithm and Partitions

The generation of efficient Gray codes and combinatorial algorithms that list all the members of a combinatorial object has received a lot of attention in the last few years. Knuth gave a code for the set of all partitions of [n] = {1,2,...,n}. Ruskey presented a modified version of Knuth’s algorithm with distance 2. Ehrlich introduced a looplees algorithm for the set of the partitions of [n]; Ruskey and Savage generalized Ehrlich’s results and introduced two Gray codes for the set of partitions of [n]. In this paper, we give another combinatorial Gray code for the set of the partitions of [n] which differs from the aforementioned Gray codes. Also, we construct a different loopless algorithm for generating the set of all partitions of [n] which gives a constant time between successive partitions in the construction process.      

Similarity Solutions for Generalized Variable Coefficients Zakharov-Kuznetsov Equation under Some Integrability Conditions

In this paper, the symmetry method has been carried over to the generalizedvariable coefficients Zakharov-Kuznetsov equation. The infinitesimalsymmetries and the optimal system are deduced and from this optimal systemseven basic fields are determined, and for every vector field in the optimalsystem the admissible forms of the coefficients are found and this also leadsus to transform the given equation into partial differential equations intwo variables. After using some referenced transformations the mentionedpartial differential equations eventually reduce to ordinary differentialequations. The search for solutions to those equations has yielded manyexact solutions in most cases.     

Novel Indole-Pyrazine Alkaloid: Synthesis,Characterization, and Crystal Structure

Crystallography Reports - A heterocyclic molecule of a novel class with a multiple ring system has been synthesized using a new and simple strategy and acetic acid as catalyst. The structure of the...