Thermal studies on protein isolates of white lupin seeds (<Emphasis Type="Italic">Lupinus albus</Emphasis>)

This study used TG, DSC, and SDS-PAGE techniques to study protein isolates (PIs) in the powder form obtained from lupin seeds flour Lupinus albus. Different methods of preparing PIs were tested, resulting in final products that were different only in relation to the yield and protein content. The results of the protein analysis by SDS-PAGE showed that the same protein fractions were present in the lupin seeds and in the obtained PIs. This result shows that the process of extraction was not damaging to the composition of the original protein. On the other hand, the results of the thermal analysis (DSC and TG–DTG curves) obtained for the different PIs, led to the detection of changes in the protein conformation through the ΔH values, which in general decreased with increasing values of pH and ionic strength in the experimental conditions of extraction.     

One-pot multicomponent synthesis of 1,2,3,4-tetrasubstituted pyrroles catalyzed by [NMPH]CH3SO3

A general method for the synthesis of 1,2,3,4-tetrasubstituted pyrroles by [NMPH]CH₃SO₃ is reported. A full factorial design was performed in order to obtain a more robust and statistically correct optimum condition. The products were obtained in moderate to excellent yields. The developed methodology is very simple, cost-effective, and applicable for tri- and tetra-component reactions.     

Lanthanum-Catalyzed Enantioselective Trifluoromethylation by Using an Electrophilic Hypervalent Iodine Reagent

A highly enantioselective catalytic method for the synthesis of quaternary α-trifluoromethyl derivatives of 3-oxo esters is described. The reaction uses lanthanum(III) triflate and chiral PyBOX-type C₂-symmetric ligands to generate intermediate La^III complexes that incorporate an enolate moiety of the starting 3-oxo ester and the trifluoromethylation transfer reagent. The enantioselectivity of the reaction stems from the efficient blockage of one of the prochiral faces of the La^III enolate by one unit of the C₂-symmetric ligand.     

[All]-S,S-dioxide Oligo-Thienylenevinylenes: Synthesis and Structural/Electronic Shapes from Their Molecular Force Fields

Oligo-S,S-dioxothienylenevinylenes have been prepared by transferring oxygen atoms to the sulfur atoms using the HOF ⋅ CH₃CN complex. Their photophysical properties are presented in comparison with their thiophenevinylene congeners. Together with their vibrational properties and molecular force fields, this study allows for the interpretation of the alteration of aromaticity and inter-ring exocyclic π-conjugation in this series.     

Peroxidase activity of new mixed‐valence cobalt complexes with ligands derived from pyridoxal

New mixed‐valence cobalt complexes with ligands derived from pyridoxal were synthesized and characterized, and their application as mimetics of the peroxidase enzyme was investigated. Single‐crystal X‐ray diffraction was used to analyze all complex structures in the solid state and their electrochemical behavior was investigated. A reactivity pattern was observed in the complex synthesis regarding the cobalt compounds from which analogous zwitterionic derivatives were obtained. The importance of these compounds lies in understanding their behavior in an oxidizing environment and evaluating whether they can activate hydrogen peroxide to oxidize phenolic compounds. In nature, enzymes called peroxidases, which efficiently oxidize phenolic compounds, trigger many reactions involving the activation of hydrogen peroxide to oxidize organic substrates. However, these enzymes present several disadvantages, including denaturation and elevated costs. Therefore, these limitations can be overcome by expanding research into the study of synthetic catalysts for the oxidation of phenolic compounds using hydrogen peroxide, which is a highly relevant field of bioinorganic chemistry.     

Exact and heuristic methods to solve a bi-objective problem of sustainable cultivation

Annals of Operations Research - This work proposes a binary nonlinear bi-objective optimization model for the problem of planning the sustainable cultivation of crops. The solution to the problem...     

Jet Dynamics in Black Hole Physics: Acceleration During Subparsec Collimation

We study the processes of particle acceleration which take place in the field of a rotating black hole as part of a mechanism of formation of galactic jets within the first parsec from the central source, where gravitation is supposed to be dominant. We find the Lorentz factor that a stream of particles acquires as function of distance, when the orbital parameters vary slightly due to a local electromagnetic field or a pressure gradient.