How solvent determines the molecular reactive conformation and the selectivity: Solvation spheres and energy.

In solution, the solvent determines the molecular conformation and the chemical reaction viability and selectivity. When solvent-solute and solvent-solvent interactions present similar strengths, explicit salvation is the best way to describe a system. The problem to solve is how big the explicit shell should be.

Liposomes Loaded with Cisplatin and Magnetic Nanoparticles: Physicochemical Characterization, Pharmacokinetics, and In-Vitro Efficacy.

With the aim improving drug delivery, liposomes have been employed as carriers for chemotherapeutics achieving promising results; their co-encapsulation with magnetic nanoparticles is evaluated in this work. The objective of this study was to examine the physicochemical characteristics, the pharmacokinetic behaviour, and the efficacy of pegylated liposomes loaded with cisplatin and magnetic nanoparticles (magnetite) (Cis-MLs). Cis-MLs were prepared by a modified reverse-phase evaporation method.

Investigation on the self-association of an inorganic coordination compound with biological activity (Casiopeína III-ia) in aqueous solution.

From studies using different experimental techniques employed to determine the presence of aggregates e.g. isothermal titration calorimetry, surface tension, electrical conductivity, UV-Vis spectrophotometry, dynamic and static light scattering, it is clearly demonstrated that the compound [Cu(4, 4'-dimethyl-2, 2'-bipyridine)(acetylacetonato)HO]NO (Casiopeína III-ia), promising member of a family of new generation compounds for cancer treatment, is able to auto associate in aqueous media.

Size product modulation by enzyme concentration reveals two distinct levan elongation mechanisms in Bacillus subtilis levansucrase.

Two levan distributions are produced typically by Bacillus subtilis levansucrase (SacB): a high-molecular weight (HMW) levan with an average molecular weight of 2300 kDa, and a low-molecular weight (LMW) levan with 7.2 kDa. Previous results have demonstrated how reaction conditions modulate levan molecular weight distribution.

Intrinsic Levanase Activity of Bacillus subtilis 168 Levansucrase (SacB).

Levansucrase catalyzes the synthesis of fructose polymers through the transfer of fructosyl units from sucrose to a growing fructan chain. Levanase activity of Bacillus subtilis levansucrase has been described since the very first publications dealing with the mechanism of levan synthesis. However, there is a lack of qualitative and quantitative evidence regarding the importance of the intrinsic levan hydrolysis of B.

Experiment and prediction: a productive symbiosis in studies on the thermodynamics of DNA oligomers.

Recently, we reported the kinetics of hybridization of cDNA dodecamers (Carrillo-Nava, E., Mejía-Radillo, Y., and Hinz, H.

Dodecamer DNA duplex formation is characterized by second-order kinetics, positive activation energies, and a dependence on sequence and Mg2+ ion concentration.

This study provides quantitative information about the kinetics of formation of a complex between DNA oligomers having 12 bp. The DNA dodecamers were designed in such a way as to avoid the formation of hairpins or slipped duplex structures within single strands. The hybridization was carried out employing stopped-flow techniques.

Thermal unfolding of triosephosphate isomerase from Entamoeba histolytica: dimer dissociation leads to extensive unfolding.

In mesophiles, triosephosphate isomerase (TIM) is an obligated homodimer. We have previously shown that monomeric folding intermediates are common in the chemical unfolding of TIM, where dissociation provides 75% of the overall conformational stability of the dimer. However, analysis of the crystallographic structure shows that, during unfolding, intermonomeric contacts contribute to only 5% of the overall increase in accessible surface area.

Association temperature governs structure and apparent thermodynamics of DNA-gold nanoparticles.

Apparent thermodynamics of association of DNA-modified gold nanoparticles has been characterized by UV spectroscopy and dynamic light scattering (DLS). Extinction coefficients of unlabelled and DNA-labelled gold nanoparticles have been determined to permit quantitative analysis of the absorption measurements. In contrast to previous studies the associating gold nanoparticles were furnished with complementary oligonucleotide DNA single strands.

Modeling Gibbs energies of solution for a non-polar solute in aqueous solutions of the protein stabilizers glycerol and ethylene glycol.

The Hydration Shell Chemical Equilibrium Model (HSCE) has been applied to Gibbs energies of solution data for toluene in aqueous solutions of the protein stabilizers glycerol and ethylene glycol. The HSCE model fits the experimental data to nearly experimental uncertainty. This satisfactory rendering of the data provides certainty on the physical significance of the model parameters and allows a description, from the molecular point of view, of the behaviour of a non-polar solute in aqueous solutions of protein stabilizers.