Immobilized microorganisms in the reduction of ethyl benzoylacetate

The enantioselective reduction of ethyl benzoylacetate (EBA) into ethyl (S)-3-hydroxy-3-phenylpropanoate (S-HPPE) by nine yeast strains and three filamentous fungi strains is described. The conversion obtained was in the range 0-89% and the enantiomeric excess was 100% in many cases. Conversion levels were higher when the reduction was performed with microorganisms immobilized in calcium alginate and enantioselectivity remained excellent. Some reaction’s conditions of bioreduction by immobilized cells of Rhodotorula rubra were studied using a 2^5-2 fractional factorial design.     

Complete and Stable O(p+1)×O(q+1)-Invariant Hypersurfaces with Zero Scalar Curvature in Euclidean Space ℝ p+q+2

We classify the zero scalar curvature O(p+1)×O(q+1)-invariant hypersurfaces in the euclidean space ℝ ^p+q+2, p,q > 1, analyzing whether they are embedded and stable. The Morse index of the complete hypersurfaces show the existence of embedded, complete and globally stable zero scalar curvature O(p+1)×O(q+1)-invariant hypersurfaces in ℝ ^p+q+2, p+q≥ 7, which are not homeomorphic to ℝ ^p+q+1. Such stable examples provide counter-examples to a Bernstein-type conjecture in the stable class, for immersions with zero scalar curvature. Mathematics Subject Classifications (2000): 53A10, 53C42,49005.     

What do we know about the ionic liquid effect in catalyzed multicomponent reactions?: A critical review

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Methane activation on PdMn/C-ITO electrocatalysts using a reactor-type PEMFC

Various palladium and manganese supported in a mix of carbon and indium thin oxide (PdMn/C-ITO) compositions were synthesized by a sodium borohydride reduction process for methane activation at low temperatures in a proton exchange membrane fuel cell (PEMFC) reactor. These electrocatalysts were characterized by X-ray diffraction, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy XPS, inductively coupled plasma mass spectrometry ICP-MS, attenuated total reflection-Fourier transform infrared spectroscopy, cyclic voltammetry and a PEMFC reactor. The diffractograms of PdMn/C-ITO electrocatalysts revealed the face-centered cubic structure of palladium and the bixbyite cubic structure of In₂O₃. TEM experiments showed mean nanoparticle sizes between 4.7 and 5.2 nm for all electrocatalysts. XPS results showed the presence of palladium and manganese oxides, as well as Pd⁰ species. Cyclic voltammograms of PdMn/C-ITO electrocatalysts showed an increase in current density values after the methane adsorption, this result is related to formation of methanol or formic acidic. Polarization curves at 80 °C acquired in a PEMFC reactor showed that PdMn(70:30)/C-ITO and PdMn(50:50)/C-ITO have superior performance when compared to Pd/C-ITO indicating the beneficial effect of adding Mn, this behavior can be attributed to the bifunctional mechanism or to the electronic effect of support.

     

Zn-Co electrocatalysts in lithium-O2 batteries: temperature and rotating cathode effects on the electrodeposition

Journal of Solid State Electrochemistry - In this study, we developed Zn-Co catalyst by electrodeposition process in nickel foam and steel mesh electrodes for application as a cathode in Li-O2...     

Band Monoid Languages Revisited

We describe the atoms of the varieties of band monoid languages as disjoint unions of concatenations of words and free monoids. We present a new proof of a solution of the word problem for the free band due to Siekman and Szabo.