Stable open-shell aromatic nitric acid radicals: accessing highly efficient photothermal conversion with restricted radiative decay

Most of the open-shell radicals are usually thermodynamically or kinetically unstable in air due to their incompletely satisfied valency. As phenol radical without steric hindrance group protection, aromatic nitric acid radical exhibits high electrochemical and thermal stability due to its rich resonance structures including closed-shell nitro-like and open-shell nitroxide structure with unpaired electrons delocalized in conjugated backbones. Herein, a series of star-shaped aromatic nitric acid radical materials were prepared via facile demethylation and consequent oxidation of their phenolic hydroxyl precursors in air. Interestingly, they exhibit extremely high spin concentration and highly enhanced nonradiative decay, which make them exhibit great potential for photothermal conversion. Among them, TPA-TPA-O6 exhibits high photothermal conversion efficiency and negligible photobleaching effect in seawater desalination. Under irradiation of one sunlight, the water evaporation efficiency of TPA-TPA-O6 is recorded as high as 89.41% and the water evaporation rate is 1.293 kg/m2 h, which represent as the top performance in pure organic small molecule photothermal materials.

EFFECT OF PASTEURIZATION ON THE ANTIOXIDANT AND OXIDANT PROPERTIES OF HUMAN MILK

ABSTRACT Objective: To evaluate the effect of pasteurization on antioxidant and oxidant properties of human milk. Methods: 42 samples of milk before and after pasteurisation were used to evaluate the antioxidant activity by the ferric reducing capacity and by scavenging the 2,2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid radical. Lipid peroxidation was estimated by the concentration of malondialdehyde product using the thiobarbituric acid reactive substances assay and by the evaluation of advanced oxidation protein products. Results: No significant difference was observed in fresh human milk and after pasteurization in relation to antioxidant properties determined by the ferric reducing capacity (50.0±3.4% and 48.8±3.0%, respectively) and by scavenging the 2,2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid radical (28.9±1.5% and 31.2±1.3%, respectively). The results of malondialdehyde (62.6±4.1 and 64.3±3.6 µM/mg) and protein oxidation products (59.4±3.4 and 54.2±3.8 µM/L) of fresh and pasteurized milk, respectively, did not exhibited any significant difference. Conclusions: This data showed that human milk has an important antioxidant activity and that the pasteurizing process does not influence the antioxidant capacity, avoiding the peroxidation of breast milk lipids and the formation of advanced protein oxidation products.

Vasorelaxant Effects Induced by Red Wine and Pomace Extracts of Magliocco Dolce cv.

Several epidemiological studies demonstrate that moderate (red) wine consumption may afford protection against cardiovascular diseases. Protection is ascribed to the biological activity of wine components, many of which, however, are discarded during winemaking. In vitro rat thoracic aorta rings contracted with phenylephrine or KCl were used to assess the vasorelaxant activity of extracts from wine pomaces (seeds and skins) of the Calabrian autochthonous grape variety Magliocco dolce (Arvino). NMR spectroscopy was used to ascertain their chemical composition. Data demonstrate that seed and skin, but not must, extracts are capable of relaxing vascular preparations in an endothelium-dependent manner, similarly to the red wine extract, due to the presence of comparable amounts of bioactive constituents. In rings pre-contracted with 20–30 mM KCl, only seed extracts showed a moderate relaxation. The most efficacious vasodilating extract (wine) showed a good antioxidant profile in both [(2,2-diphenyl-1-picrylhydrazyl)acid] radical (DPPH) and [2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)] radical (ABTS) assays. In conclusion, winemaking from Magliocco dolce grape can provide potentially health-promoting by-products useful in cardiovascular disease management.

Stereoselective Synthesis of Unnatural α-Amino Acids through Photoredox Catalysis

A protocol for stereoselective C-radical addition to a chiral glyoxylate-derived sulfinyl imine was developed through visible light-promoted photoredox catalysis, providing a convenient method for the synthesis of unnatural α-amino acids. The developed protocol allows the use of ubiquitous carboxylic acids as radical precursors without prior derivatization. The protocol utilizes near-stoichiometric amounts of the imine and the acid radical precursor in combination with a catalytic amount of an organic acridinium-based photocatalyst. The mechanism for the developed transformation is discussed and the stereodetermining radical addition step was studied by the DFT calculations.

Stereoselective Synthesis of Unnatural α-Amino Acids through Photoredox Catalysis

A protocol for stereoselective C-radical addition to a chiral glyoxylate-derived sulfinyl imine was developed through visible light-promoted photoredox catalysis, providing a convenient method for the synthesis of unnatural α-amino acids. The developed protocol allows the use of ubiquitous carboxylic acids as radical precursors without prior derivatization. The protocol utilizes near-stoichiometric amounts of the imine and the acid radical precursor in combination with a catalytic amount of an organic acridinium-based photocatalyst. The mechanism for the developed transformation is discussed and the stereodetermining radical addition step was studied by the DFT calculations.

Prediction of acid radical ion binding residues by K-nearest neighbors classifier

Background Proteins perform their functions by interacting with acid radical ions. Recently, it was a challenging work to precisely predict the binding residues of acid radical ion ligands in the research field of molecular drug design. Results In this study, we proposed an improved method to predict the acid radical ion binding residues by using K-nearest Neighbors classifier. Meanwhile, we constructed datasets of four acid radical ion ligand (NO2−, CO32−, SO42−, PO43−) binding residues from BioLip database. Then, based on the optimal window length for each acid radical ion ligand, we refined composition information and position conservative information and extracted them as feature parameters for K-nearest Neighbors classifier. In the results of 5-fold cross-validation, the Matthew’s correlation coefficient was higher than 0.45, the values of accuracy, sensitivity and specificity were all higher than 69.2%, and the false positive rate was lower than 30.8%. Further, we also performed an independent test to test the practicability of the proposed method. In the obtained results, the sensitivity was higher than 40.9%, the values of accuracy and specificity were higher than 84.2%, the Matthew’s correlation coefficient was higher than 0.116, and the false positive rate was lower than 15.4%. Finally, we identified binding residues of the six metal ion ligands. In the predicted results, the values of accuracy, sensitivity and specificity were all higher than 77.6%, the Matthew’s correlation coefficient was higher than 0.6, and the false positive rate was lower than 19.6%. Conclusions Taken together, the good results of our prediction method added new insights in the prediction of the binding residues of acid radical ion ligands.