Visceral leishmaniosis is a neglected tropical disease. We evaluated the spatial distribution of cases of visceral leishmaniosis in the state of Alagoas, Brazil. All cases of VL, registered by the ...health department, were analyzed and georeferenced. Results: Between 2008 and 2017, 97.1% of the municipalities presented sporadic classification of transmission. With temporal evolution, the incidence of cases of visceral leishmaniosis was concentrated in most municipalities in the microregion of Santana do Ipanema-AL. Space-time analysis, if considered, may promote the improvement of surveillance and control actions of visceral leishmaniosis.
Novel LDH-based nanocontainers of corrosion inhibitor are developed in the present work. The reservoirs are composed by nanostructured layered double Mg/Al and Zn/Al hydroxides with divanadate anions ...located in the interlayer regions. The nanocrystalline LDHs (layered double hydroxides) are able to release vanadate ions in a controllable way.
XRD, EDS and SEM methods were used in this work to study morphological and structural properties of the synthesized LDH powders. Corrosion protection effect of the LDH powders directly added to corrosive electrolyte or to commercial coatings used for aeronautical application has been studied by electrochemical impedance spectroscopy and standard accelerated corrosion tests. Aluminium alloy 2024 was used here as substrate.
The results demonstrate that both of the LDH pigments being added to corrosive media confer corrosion inhibition effect, especially Zn/Al based nanocontainers obtained by the anion-exchange approach. The coatings doped with Zn/Al LDH-nanocontainers provide well-defined self-healing effect and confer corrosion protection properties superior than currently used environmentally unfriendly chromate-based systems.
This work aims to develop and study new anticorrosion films for AZ31B magnesium alloy based on the sol–gel coating approach.
Hybrid organic–inorganic sols were synthesized by copolymerization of ...epoxy-siloxane and titanium or zirconium alkoxides. Tris(trimethylsilyl) phosphate was also used as additive to confer additional corrosion protection to magnesium-based alloy. A sol–gel coating, about 5-μm thick, shows good adhesion to the metal substrate and prevents corrosion attack in 0.005
M NaCl solution for 2 weeks. The sol–gel coating system doped with tris(trimethylsilyl)-phosphate revealed improved corrosion protection of the magnesium alloy due to formation of hydrolytically stable Mg–O–P chemical bonds.
The structure and the thickness of the sol–gel film were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The corrosion behaviour of AZ31B substrates pre-treated with the sol–gel derived hybrid coatings was tested by electrochemical impedance spectroscopy (EIS). The chemical composition of the silylphosphate-containing sol–gel film at different depths was investigated by X-ray photoelectron spectroscopy (XPS) with depth profiling.
Zn–Al layered double hydroxides (LDHs) intercalated with nitrate anions are suggested as chloride nanotraps for organic polymeric coatings. The addition of such nanotraps to a polymer layer ...drastically reduces the permeability of corrosive chloride anions through the protective coatings. In solution, Zn(2)–Al–NO3 LDHs are responsive to the concentration of chlorides and the release of nitrates is accompanied by entrapment of chlorides, with the process governed by ion-exchange equilibrium. In particular, a coating modified with LDH–NO3 was found to exhibit significantly lower permeability to chlorides when compared to both unmodified and LDH–Cl-containing coatings, which proves the applicability of LDHs in delaying coating degradation and corrosion initiation.
This study aimed to evaluate the cementation and mechanical behavior of flared root canals restored with CAD/CAM milled glass fiber post-and-core systems. Sixty-six endodontically treated human ...canines with a flared root canal were divided into three different groups according to the type of post: GPF received prefabricated posts; GREL received relined glass fiber posts, and GMILLED received CAD/CAM milled glass fiber posts. Cementation was performed with self-adhesive resin cement. The samples were submitted to x-ray microcomputed tomography analysis for the analysis of voids and gaps. The roots were sectioned and submitted to the push-out bond strength test. The load-to-fracture was evaluated in post-and-core systems. GMILLED presented lower void and lower gap volumes when compared to GPF and GREL. On the load-to-fracture test, GREL presented statistically significant higher values than GMILLED. GPF values had no statistically significant difference from the two other groups. On the push-out bond strength test, GPF presented statistically significant lower values when compared to GREL and GMILLED. The most common failure pattern was between dentin and cement in all groups. CAD/CAM milled glass fiber post-and-core systems presented an enhanced adaptation of glass fiber posts to flared root canal systems. Their results were comparable to relined posts in bond strength, while load-to-fracture-results for GMILLED were lower than those for GPF.
Zn−Al and Mg−Al layered double hydroxides (LDHs) loaded with quinaldate and 2-mercaptobenzothiazolate anions were synthesized via anion-exchange reaction. The resulting compounds were characterized ...by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy. Spectrophotometric measurements demonstrated that the release of organic anions from these LDHs into the bulk solution is triggered by the presence of chloride anions, evidencing the anion-exchange nature of this process. The anticorrosion capabilities of LDHs loaded with organic inhibitors toward the AA2024 aluminum alloy were analyzed by electrochemical impedance spectroscopy. A significant reduction of the corrosion rate is observed when the LDH nanopigments are present in the corrosive media. The mechanism by which the inhibiting anions can be released from the LDHs underlines the versatility of these environmentally friendly structures and their potential application as nanocontainers in self-healing coatings.
Corrosion protection and surface properties of Magnesium (Mg) containing 51 ppm Fe (HP-Mg) and 341 ppm Fe (CP-Mg) were assessed by EIS, AFM/SKPFM, and photoluminescence spectroscopy in NaCl solutions ...with/without fumarate (Fum), 2,5-pyridinedicarboxylate (PDCA) and salicylate (Sal) carboxylates. The PDCA was effective in corrosion inhibition of HP-Mg and CP-Mg, while the Sal was efficient in inhibition of CP-Mg only. Volta potential (VPD) changes on Mg were evaluated considering the contribution of molecular dipoles and chemical dipoles due to interaction of carboxylate groups present in carboxylates with Mg. VPD of CP-Mg increased due to adsorption of Fe(III)-salicylate complexes and salicylate molecules.
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•2,5-pyridinedicarboxylate inhibits corrosion of Mg with high and low iron levels.•Salicylate is an efficient corrosion inhibitor for Mg with high iron levels only.•Adsorption of salicylate (Sal) and FeIII-Sal complexes increase Volta potential of Mg.•Volta potential of pure Mg decreases after immersion in NaCl solution.
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► Zeolites as nanocontainers for corrosion inhibitors. ► Ce (III) as corrosion inhibitor. ► pH as the trigger mechanism of cerium release from zeolites. ► Zeolites improved the ...barrier properties of the hybrid sol–gel films. ► Ce (III) releases from Ce–zeolite and precipitates on intermetallic inclusions.
This work presents a new approach to develop active protection coating systems. Zeolite microparticles were used as reservoirs for Ce (III). The zeolites were introduced into silica–zirconia sol–gel films, improving the barrier properties of the coating and conferring active corrosion protection to the AA2024 substrate. The corrosion process changes the pH of solution locally causing release of inhibitor that precipitates in the cathodic areas. Intermetallic inclusions seem to be sites prone to the formation of these cerium rich precipitates. The protection properties of the modified coatings were assessed using EIS.
This review focuses on the determination of uranium using spectroanalytical techniques that are aimed at total determination such as flame atomic absorption spectrometry (FAAS), electrothermal atomic ...absorption spectrometry (ETAAS), inductively coupled plasma optical emission spectrometry (ICP-OES); and inductively coupled plasma mass spectrometry (ICP-MS) that also enables the determination of uranium isotopes. The advantages and shortcomings related to interferences, precision, accuracy, sample type and equipment employed in the analysis are taken into account, as well as the complexity and costs (i.e., acquisition, operation and maintenance) associated with each of the techniques. Strategies to improve their performance that employ separation and/or preconcentration steps are considered, with an emphasis given to solid-phase extraction because of its advantages compared to other preconcentration procedures.
•BjV decreases CD1d, CD83, and CD86 expression on BMDCs.•BjV did not promote the release of IL-1β, IL-6, or TNF-α.•BjV affects the maturation of DCs.
This study was designed to characterize mice bone ...marrow (BM) and bone marrow-derived dendritic cells (BMDC) and to compare the surface markers expression and inflammatory cytokine liberation in response to LPS and Bothrops jararacussu venom (BjV) stimulation. Typical morphology was observed in BM and BMDCs from the 4th up to the 8th day of culture using recombinant mouse GM-CSF and IL-4. A high basal level of MHC-II, CD1d, CD83, CD11c, CD80, and low CD86 was expressed by BM cells. After stimulation with GM-CSF/IL-4 for BMDCs differentiation, the BM cells differentiated into BMDCs presented MHC-II, CD1d, CD83, CD11c, CD86, and CD80 expression on the 4th – 8th day accompanied with high levels of TNF-α liberated. The difference between the surface markers' expression was observed in this time course in which CD1d, CD11c, and CD80 remained in high levels of expression, while MHC-II and CD83 showed moderate expression during the differentiation period. Also, cytokines liberation was monitored over the period of the BMDCs culture, and on the 6th day, low levels of IL-6 and IL-1β were found, while high levels of TNF-α on the 4th and 8th days, both of which contributed to the maturity of the BMDCs. Maturation of DCs with LPS showed significant upregulation of surface markers (MHC-II, CD1d, CD83, CD86, CD80) and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) liberation. On the other hand, BjV induced a decrease in CD1d, CD11c, CD83, and CD86 expression in mature BMDCs which was not observed when LPS was used to stimulate BMDCs which probably induces impairment in T-cell activation.
