Jonas dos Santos Sousa

Bio: Jonas dos Santos Sousa is an academic researcher. The author has contributed to research in topics: Colloidal crystal & Chemically modified electrode. The author has an hindex of 3, co-authored 12 publications receiving 23 citations.

Bioactivity and phenolic composition of extracts of noni (Morinda citrifolia L., Rubiaceae) in tomato moth (Tuta absoluta Meyrick, 1917) (Lepidoptera: Gelechiidae)

Abstract: We evaluated the bioactivity of Morinda citrifolia L., Rubiaceae on Tuta absoluta (Lepidoptera: Gelechiidae) and quantified the phenolic components. Ethanolic extracts of leaves and fruits were used in five concentrations (0.01, 0.02, 0.03, 0.04 and 0.05 mg / L). The leaves of the plants were immersed in the solution (10 s) and placed in contact with five caterpillars of the same instar in Petri dishes. The caterpillars were kept under controlled conditions, temperature of 25 ± 1 ° C, and relative humidity of 65 ± 10%, photophase of 12 h. The experimental design was completely randomized with five concentrations, five replicates with two different extracts, the control being distilled water. The phenolic composition of the extracts was determined by high-performance liquid chromatography (HPLC) based on the retention times using the standard external method. Leaf extracts and fruits of M. citrifolia had bioinseticidal activity against caterpillars (leaves at 0.02 mg / L gave 100% mortality and fruits at 0.03 mg / L gave 46.08% mortality). The greater efficiency of leaves can be attributed to their high percentage of phenolic compounds and flavonoids. Eleven phenolic compounds were identified and quantified in extracts of leaves and fruits that showed significant bioactivity. Key words: Plant bioinsecticides, secondary metabolism, plant protection, damages, olericulture.

Electrocatalytic activity of activated niclosamide on multi-walled carbon nanotubes glassy carbon electrode toward NADH oxidation

Abstract: A simple and sensitive method for the electrocatalytic detection of dihydronicotinamide adenine dinucleotide (NADH) on an activated niclosamide (activatedNIC)-based modified electrode, prepared on a glassy carbon electrode modified with multi-walled carbon nanotubes (GCE/MWCNT/activatedNIC), was developed. This modified electrode shows efficient electrocatalytic oxidation activity toward NADH, at an applied potential of 0.065 V vs Ag/AgCl, with a kinetic constant, k kin, of 1.15 × 104 L mol−1 s−1, evaluated by chronoamperometry. The sensor presents a linear response range from 10.0 up to 280.0 μM with limits of detection and quantification and sensitivity of 3 μM, 10 μM, and 2.4 nA μM−1, respectively.

Alimentos, nutracêuticos e plantas medicinais utilizados como prática complementar no enfrentamento dos sintomas do coronavírus (covid-19): uma revisão

Abstract: The present prospective work of scientific articles related to foods and natural products with anti-Covid activity in databases in order to present a scientific community, to governments and society as main foods, nutraceuticals and medicinal plants as strategies used by countries during the COVID-19 pandemic. A review of articles on food, medicinal plants and biotechnology was carried out in databases of scientific articles such as: CAPES journals, PubMed, Elsevier's Science Direct, Willey on library library, Taylor & Francis Springer-Nature database, BMC, Hindawi, Scielo, ACS American Chemical Society, Google Scholar, in addition to the Patent Database “The LENS” and “Questel-Orbit”. Foods used in daily life such as garlic, ginger, turmeric, sour orange, vegetables, lactobacilli demonstrate proven anti-virus action. Medicinal plants used by Traditional Chinese Medicine; Glycyrrhizae glabra, Armeniacae amarum Semen, Ephedrae Herba, Gypsum fibrosum, Scutellariae, Atractylodis macrocephalae, Poria Sclerotium, Citri Reticulatae Pericarpium, Pinelliae Rhizoma Praeparatum). Traditional Korean Medicine, Glycyrrhizae glabra, Panax ginseng. Traditional Indian Medicine, Indigofera tinctoria, Vitex trifolia, Gymnema sylvestre, Abutilon indicum, Leucas aspera, Cassia alata, Sphaeranthus indicus, Clitoria ternatea, Clerodendrum inerme Gaertn, Pergularia daemi e Evolvulus alsinoides, Hyoscyamus niger folk medicine as meimemdro negro, Coriandrum sativum folk medicine as coentro, Cynara scolymus, folk medicine as alcachofra, Punica granatum, folk medicine as romã and Sambucus ebulus and Sambucus nigra, folk medicine as sabugueiro. Traditional Brazilian Medicine; Glycyrrhiza glabra, Glycyrrhiza uralensis, Glycyrrhiza inflata, Glycyrrhiza eurycarpa, Mikania glomerata Sprengel, Mikania laevigata, Uncaria tomentosa, Cissampelos sympodialis also demonstrate anti-Covid activity and used during the coronavirus outbreak. Some medicinal plants, green propolis extract, red propolis extract, royal gelly, polen, honey have also been cited as anti-covid, natural anti-inflammatory and immunomodulatory products.

Analysis of Styrene Polymerization Without Surfactant and N2 Gas in Cylindrical Flask.

Abstract: The conditions of chemical synthesis can be crucial for polymerization of styrene in such a way that it can be produced latex beads at nanometric range (ϕ < 400nm). In this work, it will be analyzed how the absence of N2 and surfactant will result in colloidal particles with high affinity to agglomerate forming two kinds of nanostructured assemblies: colloidal crystals and nanowires. Four syntheses were realized and four parameters were changed: temperature, impeller speed, and initiator and styrene concentrations. The dispersion was filtered and coated on glass slides by evaporation induced self-assembly (EISA) process. Morphology and topography were observed at Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) respectively. They show how the synthesis conditions play a vital a role on the formation of self assembly nanostructures that can be applied as templates for sensors and biomaterials devices.

A new strategy for NADH sensing using ionic liquid crystals-carbon nanotubes/nano-magnetite composite platform

Abstract: Glassy carbon (GC) electrode is modified by stepwise manual casting of successive layers of ionic liquid crystals (ILC)/carbon nanotubes (CNTs) and magnetite nanoparticles. The composite [GC/(ILC-CNTs)/Fe 3 O 4 )] is used as a successful NADH biosensor. Molecular interaction of NADH is improved through the conductive and dense structure of ILC/CNTs. Magnetite nanoparticles act as electron-exchange “antennas” resulting in enhanced charge transfer at the interface, selective and sensitive oxidation of NADH. The type of ionic liquid used is key factor for sensor performance. The figures of merit for the proposed NADH sensor are: linear dynamic range of 5–700 μmol L −1 , a sensitivity of 0.0102 μA μmol −1 L, a detection limit of 34.6 nmol L −1 and a limit of quantification of 0.115 μmol L −1 . The sensor showed a stable amperometric response and anti-interfering ability in presence of ascorbic acid, tryptophan, ibuprofen and morphine.

The hemoglobin-modified electrode with chitosan/Fe3O4 nanocomposite for the detection of trichloroacetic acid

Abstract: A hemoglobin (Hb)-modified electrode based on chitosan/Fe3O4 nanocomposite coated glassy carbon has been constructed for trichloroacetic acid (TCA) detection. The structure of chitosan/Fe3O4 nanocomposite was investigated using energy-dispersive X-ray analysis (EDS) and X-ray diffraction (XRD) patterns. The electron transfer rate constant (k s) of Hb was estimated for as high as 3.12 s−1. The immobilized Hb exhibited excellent electro-catalytic activity toward the reduction of TCA. The response current regressed to the concentration of TCA within the range of 5.70 μM to 205 μM with a detection limit of 1.9 μM (S/N = 3).