A new Rose Bengal glycopolymer: Photosensitization in two stages.

Antimicrobial photodynamic therapy is a promising alternative to deal with antimicrobial resistance. However, both the low specificity and low local oxygen molecular concentrations decrease the antimicrobial efficiency limiting its use. An interesting approach to the problem is the use of molecules that can react reversibly with singlet oxygen by the formation of reversible endoperoxides, such as naphthalene, anthracene and pyridone derivatives.

Electron Spin-Dependent Electrocatalysis for the Oxygen Reduction Reaction in a Chiro-Self-Assembled Iron Phthalocyanine Device.

The chiral-induced spin selectivity effect (CISS) is a breakthrough phenomenon that has revolutionized the field of electrocatalysis. We report the first study on the electron spin-dependent electrocatalysis for the oxygen reduction reaction, ORR, using iron phthalocyanine, FePc, a well-known molecular catalyst for this reaction. The FePc complex belongs to the non-precious catalysts group, whose active site, FeN4, emulates catalytic centers of biocatalysts such as Cytochrome c.

Ag@Au bimetallic nanoparticles: an easy and highly reproducible synthetic approach for photocatalysis.

An Ag@Au bimetallic nanoparticle (BNP) formulation was developed in this work. The proposed formulation was developed using photochemical and chemical methods and non-toxic reagents, showing high reproducibility and homogeneity. The synthesized BNPs have an average size of 7 nm, a core-shell-like structure (silver core and gold shell), high colloidal and long-term stability, and superior catalytic activity under darkness and white light irradiation conditions when evaluating the reduction of 4-nitrophenol to 4-aminophenolate, with respect to the monometallic Ag and Au counterparts.

Molecular rotors as reporters for viscosity of solutions of collagen like peptides.

We have studied the suitability of using a molecular rotor-based steady-state fluorometric assay for evaluating changes in both the conformation and the viscosity of collagen-like peptide solutions. Our results indicate that a positive charge incorporated on the hydrophobic tail of the BODIPY molecular rotor favours the dye specificity as a reporter for viscosity of these solutions.

Free radicals derived from γ-radiolysis of water and AAPH thermolysis mediate oxidative crosslinking of eGFP involving Tyr-Tyr and Tyr-Cys bonds: the fluorescence of the protein is conserved only towards peroxyl radicals.

The enhanced green fluorescent protein (eGFP) is one of the most employed variants of fluorescent proteins. Nonetheless little is known about the oxidative modifications that this protein can undergo in the cellular milieu. The present work explored the consequences of the exposure of eGFP to free radicals derived from γ-radiolysis of water, and AAPH thermolysis.

Mechanism of Visible-Light Photooxidative Demethylation of Toluidine Blue O.

Experiments and theoretical calculations by density functional theory (DFT) have been carried out to examine a self-sensitized type I photooxidation of toluidine blue O (TBO). This study attempts to build a connection between visible-light photolysis and demethylation processes of methylamine compounds, such as TBO. We show that controlled photoinduced mono- and double-demethylation of TBO can be achieved.

Riboflavin-induced Type 1 photo-oxidation of tryptophan using a high intensity 365 nm light emitting diode.

The mechanism of photo-oxidation of tryptophan (Trp) sensitized by riboflavin (RF) was examined employing high concentrations of Trp and RF, with a high intensity 365 nm light emitting diode (LED) source under N, 20% and 100% O atmospheres. Dimerization of Trp was a major pathway under the N atmosphere, though this occurred with a low yield (φ = 5.9 × 10), probably as a result of extensive back electron transfer reactions between RF and Trp(H).

Theoretical rationalisation of the photophysics of a TICT excited state of cinnamoyl-coumarin derivatives in homogeneous and biological membrane models.

A new hybrid cinnamoyl-coumarin probe was synthesised to study the formation and dynamics of a twisted internal charge transfer (TICT) excited state in homogeneous and biological membrane models. This probe showed a large bathochromic shift of the fluorescence band with the solvent polarity, which is associated with the decrease in the fluorescence intensity due to fast non-radiative deactivation pathways, ascribed to TICT excited state formation in polar solvents. The calculated potential energy surfaces using density functional theory (DFT) and time dependent-DFT (TD-DFT) along with the energetic barriers calculated using the ABF methodology established the energy requirements for a rotational twisting of the cinnamoyl-coumarin bond for TICT excited state formation.

Aggregation of α- and β- caseins induced by peroxyl radicals involves secondary reactions of carbonyl compounds as well as di-tyrosine and di-tryptophan formation.

The present work examined the role of Tyr and Trp in oxidative modifications of caseins, the most abundant milk proteins, induced by peroxyl radicals (ROO). We hypothesized that the selectivity of ROO and the high flexibility of caseins (implying a high exposure of Tyr and Trp residues) would favor radical-radical reactions, and di-tyrosine (di-Tyr) and di-tryptophan (di-Trp) formation. Solutions of α- and β-caseins were exposed to ROO from thermolysis and photolysis of AAPH (2,2'-azobis(2-methylpropionamidine)dihydrochloride).

Atypical antioxidant activity of non-phenolic amino-coumarins.

Coumarin compounds have been described as anti-inflammatories, and chemotherapeutic agents as well as antioxidants. However, the origin of the antioxidant activity of non phenolic coumarins remains obscure. In the present report, we demonstrate that non-phenolic 7-dialkyl-aminocoumarins may also have significant antioxidant properties against free radicals derived from 2,2'-azobis(2-amidinopropane) dihydrochloride under aerobic conditions.

Easy and rapid preparation of benzoylhydrazides and their diazene derivatives as inhibitors of 15-lipoxygenase.

Two series of diaza derivatives were prepared by solvent-free condensation of benzoic acid and 4-substituted phenylhydrazines in order to obtain phenylhydrazides (HYD series) and, by oxidation of these compounds, the corresponding benzoyldiazenes (DIA series). Both sets were evaluated as inhibitors of soybean 15-lipoxygenase activity and antioxidant capability in the FRAP and CUPRAC assays. The most potent inhibitors of both series exhibited IC values in the low micromolar range.

Reaction of tetracycline with biologically relevant chloramines.

Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent production of hypochlorous acid (HOCl), monochloramine (NHCl), and protein-derived chloramines. As the therapy for eradicating H.

Violence and alcoholism in the family: how are the children affected?

We made an evaluation of how children and adolescents are affected if they live in a family environment where violence associated with alcoholism is a feature. Interviews with 20 families and the use of psychological tests on their children were performed in this study. The study has demonstrated the existence of psychopathological disturbances in those families' children, whose immaturity and insecurity were expressed by aggressive behaviour or by depressive manifestations.