Effects of solvents on the reaction of 2,2-dimethylpropanesulfinyl chloride with activated zinc

Although 2,2-dimethylpropanesulfinyl chloride reacts with zinc in C₆H₆ or CCl₄ to give the corresponding thiosulfonate as major product, the reaction in C₂D₁₀O, C₂H₁₀O, and CD₃CN affords the corresponding thiosulfinate as the major product.     

“Loop the loop”

The applicability of the collective coordinate method (saddle-point approximation) for large-N planar models is discussed. Some unstated assumptions are clarified. Statements that Wilson loops form a complete set of gauge invariant operators are also examined and a set of generalized algebraic Mandelstam relations among Wilson loops is presented. The inclusion of loops that wind around themselves and cross many times, as independent variables, is stressed.     

13C NMR chemical shifts of thiols,sulfinic acids,sulfinyl chlorides,sulfonic acids and sulfonic anhydrides

¹³C NMR spectra of thiols, sulfinic acids, sulfinyl chlorides, sulfonic acids and sulfonic anhydrides have been obtained. The data are discussed in terms of the additivity of the deshielding effects exerted by the sulfur functionality at the α- or β-position, and the shielding effects produced by the sulfur function at the γ-position.     

On negative cycles in mixed graphs

We show that, for mixed graphs, i.e., graphs having both directed and undirected edges, with a length function defined on the edges, the problems of detecting negative cycles and of finding the shortest path in the absence of negative cycles are NP-complete.     

Chemiluminescent evaluation of peroxide value in olive oil

A method is described for the evaluation of the peroxide value (PV, meq. O₂ kg⁻¹) in olive oil. The method is based on the chemiluminogenic energy-transfer reaction of bis(2,4,6-(trichlorophenyl)oxalate (TCPO) with hydrogen peroxide or total peroxides in the presence of Mn(II) as catalyst and 9,10-dimethylanthracene as fluorophore. The procedure developed allows the evaluation of PV within the range of 0.6-100 meq. O₂ kg⁻¹ (CL intensity = 1.76 × PV (meq. O₂ kg⁻¹) + 23.2, r² = 0.994, n = 9) and relative standard deviation within the range 1-5% by using a simple manual measurement.     

Measurement of the inhibitory potential and detoxification of biomass pretreatment hydrolysate for ethanol production

Applied Biochemistry and Biotechnology - The Microtox assay represents a rapid, accurate, and reproducible method for determining general microbial toxicity. This assay was used to evaluate the...     

Cytotoxic cuparene sesquiterpenes from Laurencia microcladia

Three new cuparene sesquiterpenes 1-3 were isolated from the organic extract of the red alga Laurencia microcladia, collected at Chios island in the North Aegean Sea, Greece. The structures and the relative stereochemistry of the compounds are proposed on the basis of their spectral data. Metabolite 2 shows an unprecedented (for the cuparene class of sesquiterpenes) migration of the C-1 methyl group. All metabolites 1-3 were found to exhibit significant cytotoxic activity against two lung cancer cell lines.     

Three-dimensional structure of nanocomposites from atomic pair distribution function analysis: study of polyaniline and (polyaniline)(0.5)V(2)O(5) x 1.0 H(2)O

The three-dimensional structures of emeraldine base polyaniline (PANI) and (polyaniline)(0.5)V(2)O(5) x 1.0 H(2)O have been determined by total X-ray scattering experiments. Atomic pair distribution functions (PDF) were measured to obtain experimental observables against which structural models were tested and refined. The PDF approach is necessary because of the limited structural coherence in these nanostructured materials. Polyaniline possesses a well-defined local atomic arrangement that can be described in terms of an 84-atom orthorhombic unit cell. The nanocomposite (PANI)(0.5)V(2)O(5) x 1.0 H(2)O too is locally well ordered and may be described in terms of a small number of structure-sensible parameters. The PDF approach allows the construction of structure models of PANI and (PANI)(0.5)V(2)O(5) x 1.0 H(2)O on the basis of which important materials' properties can be explained predicted and possibly improved.     

Dendrimers in solution: insight from theory and simulation

A variety of experimental and theoretical approaches show that, akin to linear polymers, dendrimers in good solvent conditions are best described as flexible macromolecular aggregates with a dense core and fluctuating monomer groups. We present theoretical and simulational evidence of how the shape and inner structure of dendrimers depends on the generation number as well as the effective interactions that exist between dendrimers in solution. These approaches based on simplified dendritic structures show there is a tunable and ultrasoft interaction between the centers of the solublized dendrimers. Results from small-angle neutron scattering data confirm the theory and indicate that dendrimers are model systems of ultrasoft colloids that bridge the gap between polymers and hard spheres. Dendrimers can form a class of materials analogous to the related systems of star polymers and block copolymer micelles which exhibit special properties.     

Direct electrochemical oxidation of polyacrylates

A promising elimination treatment of non-biodegradable organic pollutants is the direct electro-oxidation. In this work has been proposed the electrochemical elimination of polyacrylates by using boron-doped diamond (BDD) as anodic material. The complete elimination of organic contaminants has been obtained and this is the first case of successful electrochemical treatment of polymeric and bio-refractory species. The tests of the electrochemical oxidation have been conducted at constant current conditions and a complete elimination of organic species has been reached. The decrease of the COD value with time follows the behaviour of an ideal anode as in the case of low molecular organic compounds.