Agarose fibers with glycerol and graphene oxide and functional properties for potential application in biomaterials.

Agarose has numerous applications in biochemistry and medical textiles. This study aimed to produce agarose-graphene oxide-glycerol fibers and analyze their properties. The agarose gel was prepared by dissolving the polymer in 9:1 (v/v) dimethyl sulfoxide (DMSO): H2O, followed by spinning in an ethanol bath (1:1 (v/v) ethanol: H2O) at 20 °C. Fibers were obtained using 8 % (m/v) agarose, 2 % (m/v) glycerol, and 0.5 % and 1 % (m/v) graphene oxide (GO). The fibers had a titer of 18.32-32.49 tex and, a tenacity of 1.40-3.35 cN/tex. GO increased the thermal resistance by 79 %. The presence of glycerol and GO was confirmed and analyzed by FTIR and XPS. Fiber water absorption was decreased by 30 % with the GO addition. The weight loss increased by 55 % after glycerol addition, 51 % with GO addition, and 36 % with glycerol and GO simultaneous addition. Furthermore, GO exhibited 100 % inhibition for both S. aureus (gram-positive) and E. coli bacteria (gram-negative). Fiber F1, with only agarose, inhibited S. aureus by 34.93 %, F2 with 2 % glycerol by 48.72 %, F3 with 0.5 % GO by 63.42 %, and F4 with 2 % glycerol and 0.5 % GO by 30.65 %. However, the inhibition increased to 49.43 % with 1 % GO. The agarose fibers showed low inhibition for E. coli, ranging from 3.35 to 12.12 %.

Evaluating the catalytic effect of Fe@Fe2O3-modified granulated cork as an innovative heterogeneous catalyst in electro-fenton degradation of benzoquinone in different aqueous matrices.

This study investigated the potential of a novel biomass-derived cork as a suitable catalyst after its modification with Fe@Fe2O3 for in-situ application in heterogeneous electro-Fenton (HEF) process for benzoquinone (BQ) elimination from water. No attempts on the application of modified granulated cork (GC) as a suspended heterogeneous catalyst in the HEF process for water treatment have been published yet. GC was modified by sonification approach in a FeCl3 + NaBH4 solution to reduce the ferric ions to metallic iron in order to obtain Fe@Fe2O3-modified GC (Fe@Fe2O3/GC). Results clearly demonstrated that this catalyst exhibited excellent electrocatalytic properties, such as a high conductivity as well as relatively high redox current and possessed several active sites for water depollution applications. Using Fe@Fe2O3/GC as catalyst in HEF, 100% of BQ removal was achieved in synthetic solutions by applying 33.3 mA cm-2 after 120 min. Different experimental conditions were tested to determine that best possible conditions can be as follow: 50 mmol L-1 Na2SO4 and 10 mg L-1 of Fe@Fe2O3/GC catalyst using Pt/carbon-PTFE air diffusion cell by applying 33.3 mA cm-2. Nevertheless, when Fe@Fe2O3/GC was used in the HEF approach to depollute real water matrices, no complete BQ concentration was removal achieved after 300 min of treatment, achieving between 80 and 95% of effectiveness.

The repellency effect of icaridin nanostructural solution applied on cotton knitting fabric against Lutzomyia longipalpis.

The use of repellents is considered an alternative against biting insects, including Lutzomyia longipalpis (Diptera: Psychodidae), the main vector of the protozoan Leishmania infantum, visceral leishmaniasis's (VL) etiologic agent in the Americas. This study aimed to evaluate the repellent efficacy of icaridin nanostructured solution applied on cotton knitting fabric against L. longipalpis. Arm-in-cage tests were performed in eight volunteers at different concentrations (5%, 10%, 25%, and 50%), using L. longipalpis (n = 30). The bioassay was performed in 1, 24, 48, 72, 96, 120, and 144 h after impregnation and one test after washing the fabrics with icaridin. The total repellency rate (%R) > 95% was used as a reference to define a minimum effective concentration (MEC). The results revealed that the insects' landing mean decreased significantly in different icaridin concentrations, compared with the control tests (p < 0.05) and the 25% and 50% concentrations compared to lower concentration (5%) (p < 0.05). The higher concentrations (25% and 50%) provided longer complete protection times (CPTs) with 120 and 144 h of protection, respectively and the %R of 100% for 72 and 96 h after impregnation, respectively. The 25% was the MEC (%R Total = 98.18%). Our results indicate, for the first time, that icaridin nanostructured solution applied on cotton knitting fabric proved to be an efficient repellent against L. longipalpis with the presence of repellent action even after washing. The concentration of 25% showed better efficiency and may become an efficient method for L. longipalpis biting control.

Polymer-based wafers containing in situ synthesized gold nanoparticles as a potential wound-dressing material.

Polymer-based wafers containing gold nanoparticles (AuNP) were prepared using κ-carrageenan (κC), locust bean gum (LBG) and polyvinyl alcohol (PVA) at ratios of 42/22/13% w/w and 35/15/17% w/w. The synthesized AuNPs were evaluated for their particle size and morphology. The produced wafers containing AuNPs were investigated for their physicochemical, morphological, mechanical, and swelling properties. In addition, bacterial barrier activity and in vitro cytotoxicity were also evaluated in this study. The AuNPs obtained were spherical in shape (~ 10-15 nm in diameter) and exhibited a single bell-shaped UV-vis absorption band centered ~ 540 nm. FT-IR spectra of the wafers containing AuNPs exhibited a shift of ν(O=S=O) absorption band toward a lower wavenumber and a shift of ν(OH) absorption band toward a higher wavenumber due to the coordination of OH groups to AuNPs and their interaction with O=S=O groups of κC, respectively. SEM images confirmed the porous structure of the produced wafers, being the surface area, mechanical properties, and swelling behavior directly affected by changing both the initial amount of [Au+3] and the composition of the wafers. Lastly, the produced wafers showed non-toxicity to NIH-3T3 fibroblast cells, and they also serve as a bacterial barrier. These findings endorsed the claim that the produced wafers containing AuNPs could be a promising material for wound dressing applications.

Functional group influences on the reactive azo dye decolorization performance by electrochemical oxidation and electro-Fenton technologies.

Electrochemical water treatment technologies are highly promising to achieve complete decolorization of dyebath effluents, as demonstrated by several studies reported in the literature. However, these works are focused on the treatment of one model pollutant and generalize the performances of the processes which are not transposable since they depend on the pollutant treated. Thus, in the present study, we evaluate, for the first time, the influence of different functional groups that modify the dye structure on the electrochemical process decolorization performance. The textile azo dyes Reactive Orange 16, Reactive Violet 4, Reactive Red 228, and Reactive Black 5 have been selected because they present the same molecular basis structure with different functional groups. The results demonstrate that the functional groups that reduce the nucleophilicity of the pollutant hinder the electrophilic attack of electrogenerated hydroxyl radical. Thereby, the overall decolorization efficiency is consequently reduced as well as the decolorization rate. Moreover, the presence of an additional chromophore azo bond in the molecule enhances the recalcitrant character of the azo dyes as pollutants. The formation of a larger and more stable conjugated π system increases the activation energy required for the electrophyilic attack of •OH, affecting the performance of electrochemical technologies on effluent decolorization.

Azilsartan increases levels of IL-10, down-regulates MMP-2, MMP-9, RANKL/RANK, Cathepsin K and up-regulates OPG in an experimental periodontitis model.

AIMS: The aim of this study was to evaluate the effects of azilsartan (AZT) on bone loss, inflammation, and the expression of matrix metallo proteinases (MMPs), receptor activator of nuclear factor κB ligand (RANKL), receptor activator of nuclear factor κB (RANK), osteoprotegerin (OPG), cyclooxygenase-2 (COX-2), and cathepsin K in periodontal tissue in a rat model of ligature-induced periodontitis. MATERIALS AND METHODS: Male Wistar albino rats were randomly divided into 5 groups of 10 rats each: (1) nonligated, water; (2) ligated, water; (3) ligated, 1 mg/kg AZT; (4) ligated, 5 mg/kg AZT; and (5) ligated, 10 mg/kg AZT. All groups were treated with saline or AZT for 10 days. Periodontal tissues were analyzed by histopathology and immunohistochemical detection of MMP-2, MMP-9, COX-2, RANKL, RANK, OPG, and cathepsin K. Levels of IL-1ß, IL-10, TNF-α, myeloperoxidase (MPO), and glutathione (GSH) were determined by ELISA. RESULTS: Treatment with 5 mg/kg AZT resulted in reduced MPO (p<0.05) and IL-1ß (p<0.05), increased levels of IL-10 (p<0.05), and reduced expression of MMP-2, MMP-9, COX-2, RANK, RANKL, cathepsin K, and increased expression of OPG. CONCLUSIONS: These findings reveal that AZT increases anti-inflammatory cytokines and GSH and decreases bone loss in ligature-induced periodontitis in rats.