JBCS

From the crude skin secretion of the Osteocephalus taurinus frog a novel peptide named otacidin was isolated. The de novo sequencing of this peptide was made by MALDI-TOF-MS/MS analysis, which revealed to be an anionic peptide, being only the second report of this type of peptide from an amphibian. Otacidin was tested against some bacteria presenting slight antimicrobial activity.

This review focuses on the development of metal-mediated chiral catalysts in Mukaiyama-type aldol reactions, reductive aldol reactions, direct aldol reactions and the application of these catalysts in the total synthesis of complex molecules.

During the oxidation process of biodiesel, methyl esters of fatty acids form a radical which quickly binds with oxygen in the air forming volatile products such as aldehydes, ketones, lactones, and formic, acetic, propionic and caproic acids. Products formed during the autoxidation of biodiesel can increase their corrosivity and stimulate the degradation of materials.

For the assay of sugars with DNS reagent, using microtiter plates, the heating step can be performed in a water bath accommodated in a microwave oven.

The partial charges derived from electrostatic potential on atoms C₄ and H₂₃ and the bond orders between atoms C₂ and C₄, C₃ and C₆, and C₁₀ and N₁₅ explain correctly the biological activity of a set of 21 rutaecarpine derivatives synthesized and tested against central nervous system cancer.

Quantitative structure-property relationship (QSPR) studies were conducted in this work for the development of useful in silico models for the prediction of blood-brain barrier permeation, using a large data set containing 255 structurally diverse compounds.

A series of 5-substituted-1H-tetrazoles (RCN₄H) have been synthesized by cycloaddition reaction of different aryl and alkyl nitriles with sodium azide in DMSO using CuSO₄.5H₂O as catalyst. The catalyst used is readily available and environmentally friendly.

Micrographies (inverted optical microscope) of water-in-oil model emulsions prepared with different asphaltenes fraction (fraction C5 and subfraction C8-C9) extract from a crude oil asphaltic residue.

Hydride generation (HG) and inductively coupled plasma optical emission spectrometry (ICP OES) were investigated and employed for Se and Sb determination. Cloud point extraction was used for analyte preconcentration. The HG performance was compared with that of pneumatic nebulization.

In enzymatic reaction, cholest-4-en-3-one and hydrogen peroxide form. The oxidation current of hydrogen peroxide can be detected at applied potential and the current is proportional to the concentration of cholesterol.

The study proposes a new analytical procedure based on an internally cooled solid phase microextraction technique (CF-SPME) combined with on-fiber derivatization and gas chromatography-selected ion monitoring-mass spectrometry.

The present paper reports an accurate theoretical description of absorption, fluorescence and phosphorescence spectra of zinc phthalocyanine using TD-DFT.

The chemiluminescence (CL) of the reaction, luminol-diperiodatoargentate(III) system, with catalytic effect of β-CD/MnFe₂O₄ magnetic nanoparticles is successfully applied for rapid and sensitive determination of glutathione in human blood samples.

The chemical and mineralogical composition of the rainwater in Araraquara City, Brazil, is influenced by diversity sources of atmospheric pollutants such as (a) pre-harvest burning of sugar cane crops, (b) re-suspended dust derived from soils
and (c) vehicle emissions.

We report a versatile synthesis of fourteen γ-lactones structurally related, which had their phytotoxic activity evaluated in vitro by the influence on the growth of wheat (Triticum aestivum) coleoptiles. 5-Isopropoxyfuran-2(5H)-one presented 76% inhibition of the coleoptiles at 1000 μmol L^-1 compared to the control.