Access to 3-aminobenzothiophenes and 3-aminothiophenes fused to 5-membered heteroaromatic rings through 6π-electrocyclization reaction of keteniminium salts

We described a general approach to 3-aminobenzothiophenes and 3-aminothiophenes fused to 5-membered heteroaromatic rings as thiophenes, furans and pyrroles through a 6π-elctrocyclization reaction of keteniminium salts. We investigated various substituents not only on the aromatic rings, but also at C-2 and on the nitrogen atom of the keteniminium salt. In particular, we have determined the electronic requirements of the nitrogen substitution to secure the efficient formation of the corresponding keteniminium salt. A clear relation between the pK_a of the amine leading to the formation of the keteniminium salt and the yield obtained for benzothiophene is established and should find broad application to other reactions involving these intermediates. Additional insight on the ease of this 6π-electrocyclization reaction was gained through competition reactions and DFT calculations.     

Analysis of Solanum Americanum Mill. by Ultrafast Liquid Chromatography with Diode Array and Time-Of-flight Mass Spectrometry Detection with Evaluation of Anti-Inflammatory Properties in Rodent Models

Solanum americanum Mill. has been traditionally used for the treatment of fever, stomachache, skin diseases, gynecological disorders, and different kinds of inflammation. This study evaluated the anti-inflammatory response of different extracts obtained from ripe fruits of S. americanum Mill., in experimental models and evaluated them qualitatively using ultrafast liquid chromatography with diode array and time-of-flight mass spectrometry (UFLC-DAD/TOF-MS). The inflammatory response of four extracts of ripe fruits was evaluated for the systemic and topical anti-inflammatory activities. The compounds in each extract were identified using UFLC-DAD-TOF/MS. A total of 34 compounds was identified in the four extracts. The best results were obtained in compounds from the aqueous and chloroform extracts. This study demonstrated a significant anti-inflammatory activity for the compounds present in fruit of S. americanum Mill.     

Dependence of InP and GaAs chemical beam epitaxy growth rate on substrate orientations; applications to selective area epitaxy

In order to optimize the shape of chemical beam epitaxy (CBE) selective area growth, growth rates on (100), (111)B, (111)A and (110) substrate orientations have been examined for GaAs and InP materials. (111)B GaAs growth rate appears to be drastically enhanced at low V/III ratio, which has been applied to grow selective GaAs patterns limited by vertical sidewalls. Concerning InP, high growth rates were obtained on all orientations. This was used to perfectly fill a rectangular groove by selective embedded InP growth.     

Immobilization of 5-amino-1,3,4-thiadiazole-thiol onto silica gel surface by heterogeneous and homogeneous routes

The compound 5-amino-1,3,4-thiadiazole-thiol (ATT) was anchored onto silica gel surfaces by homogeneous and heterogeneous routes. Both silica modification methodologies resulted in similar products, named SiCTT and SiATT, respectively. These materials were characterized by infrared and Raman spectroscopies, superficial area and elemental analysis as well as ¹³C and ²⁹Si NMR spectroscopy. Elemental analysis proved that the material SiCTT presented a higher ATT immobilization than SiATT, with values of 0.73 and 0.65 mmol g⁻¹, respectively. NMR, Raman and infrared spectroscopy corroborate to confirm the immobilization of ATT on both surfaces. Raman spectroscopy showed that the reaction of the ATT with silylant agent or pre-modified silica occurred by the thiol group, resulting in a surface with two sulfur groups and one free amine group able to complex soft and hard acids.     

Chemical beam epitaxy of AlGaAs and AlInAs using trimethylamine alane precursor

Al_xGa_1−xAs and Al_xIn_1−xAs alloys were grown on GaAs and InP, respectively, by chemical beam epitaxy, using trimethylamine alane (TMAA) as the source of aluminium. TMAA could be used properly only after some problems had been solved. Low carbon and oxygen concentrations were obtained in both alloys, leading to residual hole concentrations of 2 × 10¹⁶ cm^-3 in Al_0.3Ga_0.7As. The abruptness of the AlGaAs/GaAs interface proved the absence of TMAA memory effect. The control of Al_xIn_1−xAs solid composition was more difficult than for Ga_xIn_1−xAs, but was less sensitive to growth temperature. Photoluminescence intensities of Al_0.3Ga_0.7As and Al_0.48In_0.52As grown at 510°C were similar to those of MBE grown materials.     

Quasi-optimal Nonconforming Approximation of Elliptic PDEs with Contrasted Coefficients and $$H^{1+{r}}$$ , $${r}>0$$ , Regularity

Foundations of Computational Mathematics - In this paper, we investigate the approximation of a diffusion model problem with contrasted diffusivity for various nonconforming approximation methods....     

On the riesz charge of the lower envelope of δ-subharmonic functions

By potential theoretic methods involving the Cartan fine topology a recent result by two of the authors is extended as follows: The Riesz charge of the lower envelope of a family of 3 or more -subharmonic functions (no longer supposed continuous) in the plane equals the infimum of the charges of the lower envelopes of all pairs of functions from the family. As a key to this it is shown in two different ways that the (fine) harmonic measures of any 3 pairwise disjoint finely open planar sets have Borel supports with empty intersection. One proof of this uses the Jordan curve theorem and the fact that the set of inaccessible points of the fine boundary of a fine domain is Borel and has zero harmonic measure; the other involves Carleman-Tsuji type estimates together with a fine topology version of a recent result of P. Jones and T. Wolff on harmonic measure and Hausdorff dimension.     

A vortex model with superfluid and turbulent percolation

Simple lattice vortex models are presented that exhibit vortex percolation along lines in a temperature/chemical potential plane. Parts of these lines can be identified with the percolation threshold at the inertial range of turbulence, and other parts are analogous to the transition in a three-dimensionalXY model that may model the . transition in superfluidity. Flory exponents at percolation are calculated; for nonnegative temperatures, their values approximate the standard Flory value, and are approximately constant along the transition lines, in agreement with recent conjectures. Conclusions regarding coherent structures in turbulence are also reached.     

Solution of lattice models by successive linkage

A linkage algorithm is presented for evaluating the partition function of a union of finite lattice blocks in terms of the partition functions of the component blocks. This algorithm leads to: (i) A fast enumeration method for evaluating the partition function of a finite lattice (for Ising spins in two dimensions, the number of terms needed to evaluate the partition function for a block ofL spins if reduced from 2 ^L to ); (ii) a recursive factorization procedure that accelerates the rate at which quantities evaluated on a finite lattice converge to their thermodynamic limit, and (iii) a scaling procedure that further accelerates the convergence to the thermodynamic limit. The scaling procedure is similar to a method previously used in turbulence calculations.Supported in part by the Applied Mathematics Subprogram of the Office of Energy Research, U.S. Department of Energy, under contract DE-AC03-76SF0098, and in part by the Office of Naval Research under contract N00014-76-C-0316     

Heats of combustion of biofuels obtained by pyrolysis and by transesterification and of biofuel/diesel blends

The obtained heats of combustion were 46.65 ± 0.20; 38.09 ± 0.31; 39.67 ± 0.22; 41.88 ± 0.31; 37.86 ± 0.46; 39.89 ± 0.09; 41.28 ± 0.31 MJ/kg for diesel, transesterified soybean oil, pyrolysed soybean oil and crude soybean oil, transesterified palm tree oil (Elaeis sp.), pyrolysed palm tree oil, crude palm tree oil, respectively. The results show the heats of combustion of biofuels are approximately 17% smaller than traditional diesel. The data also show the heats of combustion depend on the methodology used for the biofuel production. Addition of biofuels to traditional diesel fuel results in a linear decrease of the heat of combustion with the amount of the alternative fuel added to the diesel. However, for blends with 5% biofuels, which is the limit demanded by Brazilian legislation, no significant decrease of the heat of combustion of the commercial diesel was observed.