Chitosan-magnetite nanocomposite as a sensing platform to bendiocarb determination

A novel platform for carbamate-based pesticide quantification using a chitosan/magnetic iron oxide (Chit-Fe3O4) nanocomposite as a glassy carbon electrode (GCE) modifier is shown for an analytical methodology for determination of bendiocarb (BND). The BND oxidation signal using GCE/Chit-Fe3O4 compared with bare GCE was catalyzed, showing a 37.5% of current increase with the peak potential towards less positive values, showing method's increased sensitivity and selectivity. Using square-wave voltammetry (SWV), calibration curves for BND determination were obtained (n = 3), and calculated detection and quantification limits values were 2.09 × 10-6 mol L-1 (466.99 ppb) and 6.97 × 10-6 mol L-1 (1555.91 ppb), respectively. The proposed electroanalytical methodology was successfully applied for BND quantification in natural raw waters without any sample pretreatment, proving that the GCE/Chit-Fe3O4 modified electrode showed great potential for BND determination in complex samples. ᅟ Graphical abstract.The authors gratefully acknowledge the funding provided by the following Brazilian agencies: CNPq-INCT (proc. 573925/2008-9 and 573548/2008-0), CAPES/Funcap (2133/2012/proc. 23038.007973/2012-90 and PNE-0112-00048.01.00/16), CNPq (proc. 400223/2014-7, 303596/2014-7, 302801/2014-6 and 408790/2016-4), PRONEM/FUNCAP/CNPq (PNE-0112-00048.01.00/16) and PRONEX/Funcap (proc. PR2-0101-00030.01.00/15). The Fundação para a Ciência e a Tecnologia (FCT) and the FEDER, under Programme PT2020 (Project UID/QUI/50006/2013) and the project Qualidade e Segurança Alimentar- uma abordagem (nano) tecnológica (NORTE-01-0145-FEDER-000011) are also acknowledged for the financial funding. R.M.F. and J.C.D. acknowledge the financial support by Fondecyt 3170240 and Basal Program for Centers of Excellence, Grant FB0807 CEDENNA, CONICYT. C.P.S. thanks CAPES-PNPD for her grant.info:eu-repo/semantics/publishedVersio

First Observation of an Undular Mesospheric Bore in a Doppler Duct

On 1 October 2005, during the SpreadFEx campaign, a distinct mesospheric bore was observed over S˜ao Jo˜ao do Cariri (7.4 S, 36.5 W), Brazil by using airglow allsky imagers. The event appeared both in the OI5577 and OH emissions, forming a well extended wave front which was followed by short waves from behind. Simultaneous wind and temperature data obtained by the meteor radar and the TIMED/SABER satellite instrument revealed that the bore event occurred during the Doppler ducting condition in the emission layers

Nanotechnology in hormone replacement therapy: Safe and efficacy of transdermal estriol and estradiol nanoparticles after 5 Years Follow-Up Study

This study aimed to evaluate the safety and efficacy of a novel protocol of transdermal Hormone Replacement Therapy (HRT) based on a nanostructured formulation of Estriol (0.1 %) + Estradiol (0.25 %) restoring serum levels and relieving menopausal symptoms. We evaluated 122 women with mean age of 56.88 (± 6.27) as part a longitudinal prospective study on post-menopausal women with natural menopause, received in the right forearm a transdermal formulation of (EE) daily for 60 months. Clinical parameters including the degree of satisfaction with symptomatic relief, serum concentrations of estradiol, weight, blood pressure, and bilateral mammography BI-RADS were compared between the baseline and five years after treatment. New evidence regarding this HRT protocol was assessed. The transdermal nanoformulation estradiol improved clinical parameters. Satisfaction with treatment was 92 %. Serum concentrations of estradiol changed significantly after treatment (p 0.05) over the years. No vaginal bleeding was observed. Bilateral mammography assessment of the breasts following 60 months of HRT with bioidentical estradiol treatment found normal results in all women. This paper shows for the first time the effectiveness of a nanostructured transdermal formulation enhancer on the delivery of estradiol and estriol measured in vivo using Raman Confocal Spectroscopy. The Nanostructured formulation is safe and effective in reestablishing estradiol serum levels and relieving menopausal symptoms. The nanoformulation may serve as a good choice for hormone replacement therapy to protect against other post-menopausal symptoms.Colegio de Farmacéuticos de la Provincia de Buenos Aire

The spread-F Experiment (SpreadFEx): Program overview and first results

We performed an extensive experimental campaign (the spread F Experiment, or SpreadFEx) from September to November 2005 to attempt to define the role of neutral atmosphere dynamics, specifically wave motions propagating upward from the lower atmosphere, in seeding equatorial spread F and plasma bubbles extending to higher altitudes. Campaign measurements focused on the Brazilian sector and included ground-based optical, radar, digisonde, and GPS measurements at a number of fixed and temporary sites. Related data on convection and plasma bubble structures were also collected by GOES 12 and the GUVI instrument aboard the TIMED satellite. Initial results of our analyses of SpreadFEx and related data indicate 1) extensive gravity wave (GW) activity apparently linked to deep convection predominantly to the west of our measurement sites, 2) the presence of small-scale GWactivity confined to lower altitudes, 3) larger-scaleGWactivity apparently penetrating to much higher altitudes suggested by electron density and TEC fluctuations in the E and F regions, 4) substantial GW amplitudes implied by digisonde electron densities, and 5) apparent direct links of these perturbations in the lower F region to spread F and plasma bubbles extending to much higher altitudes. Related efforts with correlative data are defining 6) the occurrence and locations of deep convection, 7) the spatial and temporal evolutions of plasma bubbles, the 8) 2D (height-resolved) structures of plasma bubbles, and 9) the expected propagation of GWs and tides from the lower atmosphere into the thermosphere and ionosphere

Magnetic nanosystem for cancer therapy using oncocalyxone A, an antitomour secondary metabolite isolated from a Brazilian plant

none14siThis paper describes the investigation and development of a novel magnetic drug delivery nanosystem (labeled as MO-20) for cancer therapy. The drug employed was oncocalyxone A (onco A), which was isolated from Auxemma oncocalyx, an endemic Brazilian plant. It has a series of pharmacological properties: antioxidant, cytotoxic, analgesic, anti-inflammatory, antitumor and antiplatelet. Onco A was associated with magnetite nanoparticles in order to obtain magnetic properties. The components of MO-20 were characterized by XRD, FTIR, TGA, TEM and Magnetization curves. The MO-20 presented a size of about 30 nm and globular morphology. In addition, drug releasing experiments were performed, where it was observed the presence of the anomalous transport. The results found in this work showed the potential of onco A for future applications of the MO-20 as a new magnetic drug release nanosystem for cancer treatment.openBarreto, Antônio C.H.; Santiago, Vivian R.; Freire, Rafael M.; Mazzetto, Selma E.; Denardin, Juliano C.; Mele, Giuseppe; Cavalcante, Igor M.; Ribeiro, Maria E.N.P.; Ricardo, Nágila M.P.S.; Gonçalves, Tamara; Carbone, Luigi; Lemos, Telma L.G.; Pessoa, Otília D.L.; Fechine, Pierre B.A.*Barreto, Antônio C. H.; Santiago, Vivian R.; Freire, Rafael M.; Mazzetto, Selma E.; Denardin, Juliano C.; Mele, Giuseppe; Cavalcante, Igor M.; Ribeiro, Maria E. N. P.; Ricardo, Nágila M. P. S.; Gonçalves, Tamara; Carbone, Luigi; Lemos, Telma L. G.; Pessoa, Otília D. L.; Fechine, Pierre B. A

Magnetic Porous Controlled Fe3O4–Chitosan Nanostructure: An Ecofriendly Adsorbent for Efficient Removal of Azo Dyes

In this work, chitosan/magnetite nanoparticles (ChM) were quickly synthesized according to our previous report based on co-precipitation reaction under ultrasound (US) irradiation. Besides ChM was in-depth structurally characterized, showing a crystalline phase corresponding to magnetite and presenting a spheric morphology, a “nanorod”-type morphology was also obtained after increasing reaction time for eight minutes. Successfully, both morphologies presented a nanoscale range with an average particle size of approximately 5–30 nm, providing a superparamagnetic behavior with saturation magnetization ranging from 44 to 57 emu·g−1. As ChM nanocomposites have shown great versatility considering their properties, we proposed a comparative study using three different amine-based nanoparticles, non-surface-modified and surface-modified, for removal of azo dyes from aqueous solutions. From nitrogen adsorption–desorption isotherm results, the surface-modified ChMs increased the specific surface area and pore size. Additionally, the adsorption of anionic azo dyes (reactive black 5 (RB5) and methyl orange (MO)) on nanocomposites surface was pH-dependent, where surface-modified samples presented a better response under pH 4 and non-modified one under pH 8. Indeed, adsorption capacity results also showed different adsorption mechanisms, molecular size effect and electrostatic attraction, for unmodified and modified ChMs, respectively. Herein, considering all results and nanocomposite-type structure, ChM nanoparticles seem to be a suitable potential alternative for conventional anionic dyes adsorbents, as well as both primary materials source, chitosan and magnetite, are costless and easily supplied

Dwarf-green coconut fibers: A versatile natural renewable raw bioresource. Treatment, morphology, and physicochemical properties

Dwarf-green coconut fibers were modified by alkali treatment and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), as well as thermogravimetric (TGA), mechanical, and dielectric analyses. Changes in composition, structure, and morphology of the coconut fibers were observed after sodium hydroxide treatments due to the removal of lignin, hemicellulose, and other impurities. The XRD data were in agreement with the morphological analysis, where the crystallinity fraction increased with the concentration of alkali solution and fell off above 10%. The infrared spectrometry showed the partial dissolution of hemicellulose, lignin, and pectin, which was clearly identified by the band at 1736 cm-1. Thermogravimetric analysis showed a double degradation process for the untreated dwarf-green coconut fibers, while a single one was observed after the pretreatment. The tensile properties showed an increased elongation at break, modulus, and strength, and the dielectric results showed a decrease of all parameters (permittivity, dielectric loss, and conductivity), reflecting the reduced dipole and ion mobility associated with the loss of amorphous components

Effect of Photoluminescence of Nanomaterials to Verify Corrosion in Carbon Steel

The use of fluorescent nanomaterials in various fields of study has become increasingly common. In this work, the use of carbon quantum dots as a corrosion marker in carbon steel is proposed. To produce the sensor, carbon quantum dots based on ethylenediamine and citric acid were used, dissolved in a polymeric matrix. The quantum dot used showed a quantum yield of 42.34%. The nanomodified coatings emitted blue light under ultraviolet radiation lamp. However, it was observed that there is a loss of photoluminescence in the coating on the carbon steel substrate compared to the coating on the polymeric substrate, which maintained photoluminescence activity after natural exposure. Thus, it is inferred that the loss of photoluminescence may be associated with the corrosion process

Graphene and its derivatives: understanding the main chemical and medicinal chemistry roles for biomedical applications

Over the past few years, there has been a growing potential use of graphene and its derivatives in several biomedical areas, such as drug delivery systems, biosensors, and imaging systems, especially for having excellent optical, electronic, thermal, and mechanical properties. Therefore, nanomaterials in the graphene family have shown promising results in several areas of science. The different physicochemical properties of graphene and its derivatives guide its biocompatibility and toxicity. Hence, further studies to explain the interactions of these nanomaterials with biological systems are fundamental. This review has shown the applicability of the graphene family in several biomedical modalities, with particular attention for cancer therapy and diagnosis, as a potent theranostic. This ability is derivative from the considerable number of forms that the graphene family can assume. The graphene-based materials biodistribution profile, clearance, toxicity, and cytotoxicity, interacting with biological systems, are discussed here, focusing on its synthesis methodology, physicochemical properties, and production quality. Despite the growing increase in the bioavailability and toxicity studies of graphene and its derivatives, there is still much to be unveiled to develop safe and effective formulations

Ethyl butyrate synthesis catalyzed by lipases A and B from candida antarctica immobilized onto magnetic nanoparticles. Improvement of biocatalysts’ performance under ultrasonic irradiation

The synthesis of ethyl butyrate catalyzed by lipases A (CALA) or B (CALB) from Candida antarctica immobilized onto magnetic nanoparticles (MNP), CALA-MNP and CALB-MNP, respectively, is hereby reported. MNPs were prepared by co-precipitation, functionalized with 3-aminopropyltriethoxysilane, activated with glutaraldehyde, and then used as support to immobilize either CALA or CALB (immobilization yield: 100 ± 1.2% and 57.6 ± 3.8%; biocatalysts activities: 198.3 ± 2.7 Up-NPB/g and 52.9 ± 1.7 Up-NPB/g for CALA-MNP and CALB-MNP, respectively). X-ray diffraction and Raman spectroscopy analysis indicated the production of a magnetic nanomaterial with a diameter of 13.0 nm, whereas Fourier-transform infrared spectroscopy indicated functionalization, activation and enzyme immobilization. To determine the optimum conditions for the synthesis, a four-variable Central Composite Design (CCD) (biocatalyst content, molar ratio, temperature and time) was performed. Under optimized conditions (1:1, 45 °C and 6 h), it was possible to achieve 99.2 ± 0.3% of conversion for CALA-MNP (10 mg) and 97.5 ± 0.8% for CALB-MNP (12.5 mg), which retained approximately 80% of their activity after 10 consecutive cycles of esterification. Under ultrasonic irradiation, similar conversions were achieved but at 4 h of incubation, demonstrating the efficiency of ultrasound technology in the enzymatic synthesis of esters.This research was funded by Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico (FUNCAP), grant numbers BP3-0139-00005.01.00/18 and PNE-0112-00048.01.00/16, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grant numbers 422942/2016-2, 409058/2015-5 and 408790/2016-4, Coordenação de Aperfeiçoamento de Ensino Superior (CAPES-Finance Code 001) and MICIU, grant number CTQ2015-68951-C3-3-R.Peer reviewe