α-Fe2O3/, Co3O4/, and CoFe2O4/MWCNTs/Ionic Liquid Nanocomposites as High-Performance Electrocatalysts for the Electrocatalytic Hydrogen Evolution Reaction in a Neutral Medium.

Transition metal oxides are a great alternative to less expensive hydrogen evolution reaction (HER) catalysts. However, the lack of conductivity of these materials requires a conductor material to support them and improve the activity toward HER. On the other hand, carbon paste electrodes result in a versatile and cheap electrode with good activity and conductivity in electrocatalytic hydrogen production, especially when the carbonaceous material is agglomerated with ionic liquids. In the present work, an electrode composed of multi-walled carbon nanotubes (MWCNTs) and cobalt ferrite oxide (CoFe2O4) was prepared. These compounds were included on an electrode agglomerated with the ionic liquid N-octylpyridinium hexafluorophosphate (IL) to obtain the modified CoFe2O4/MWCNTs/IL nanocomposite electrode. To evaluate the behavior of each metal of the bimetallic oxide, this compound was compared to the behavior of MWCNTs/IL where a single monometallic iron or cobalt oxides were included (i.e., α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL). The synthesis of the oxides has been characterized by X-ray diffraction (XRD), RAMAN spectroscopy, and field emission scanning electronic microscopy (FE-SEM), corroborating the nanometric character and the structure of the compounds. The CoFe2O4/MWCNTs/IL nanocomposite system presents excellent electrocatalytic activity toward HER with an onset potential of -270 mV vs. RHE, evidencing an increase in activity compared to monometallic oxides and exhibiting onset potentials of -530 mV and -540 mV for α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL, respectively. Finally, the system studied presents excellent stability during the 5 h of electrolysis, producing 132 µmol cm-2 h-1 of hydrogen gas.

Wear Rate, Tribo-Corrosion, and Plastic Deformation Values of Co-Cr-Mo Alloy in Ringer Lactate Solution.

This study investigates the tribocorrosion performance of a cast Co-Cr-Mo alloy prepared using casting and electromagnetic stirring (EMS) at specific frequencies. The tribocorrosion behaviour of the alloy was evaluated when exposed to Ringer's lactate solution to optimize the EMS parameters and improve its properties. The research focuses on biomedical implant applications and explores how EMS affects alloy wear and corrosion resistance. As did the friction coefficient and wear volume, the wear rate of samples produced with EMS frequencies of 75 Hz and 150 Hz decreased. These improvements are attributed to the ability of EMS to refine grain size and homogenize the microstructure, thereby increasing the resistance to tribocorrosion. Techniques such as scanning electron microscopy (SEM) and profilometry were used for surface and wear analysis, while mechanical properties were evaluated through instrumented indentation tests. The findings confirm that EMS improves the alloy's durability and tribocorrosion resistance, making it highly suitable for demanding biomedical applications such as joint replacements. This highlights the importance of advanced manufacturing techniques in optimizing biomedical alloys for simulated body conditions.

Overt nickel and cobalt hypersensitivity after pipeline embolization device placement: A case report.

Nickel and cobalt are frequently found in metallic alloys used in the manufacture of aneurysm clips and endovascular prostheses, such as the pipeline embolization device (PED). Nickel hypersensitivity can affect up to 15% of the population, however, it is very rarely overt in patients who undergo endovascular stent placement. Here, we present the case of a 35-year-old woman who developed allergic symptoms after PED placement and was later confirmed to be allergic to both nickel and cobalt by patch testing. Fortunately, she responded well to pharmacologic treatment, rendering surgical intervention unnecessary. To the best of our knowledge, this is the first report of symptomatic nickel hypersensitivity, and the second report of symptomatic cobalt allergy caused by the PED. Despite its low prevalence, we believe that surgeons should actively inquire patients in the postoperative period about allergic symptoms, to facilitate early diagnosis and treatment.

Cobalt Oxide on Boron-Doped Graphitic Carbon Nitride as Bifunctional Photocatalysts for CO2 Reduction and Hydrogen Evolution.

In this work, the prepared cobalt oxide decorated boron-doped g-C3N4 (CoOx/g-C3N4) heterojunction exhibits remarkable activity in CO2 reduction (CO2RR), resulting in high yields of CH3COOH (∼383 µmol·gcatalyst-1) and CH3OH (∼371 µmol·gcatalyst-1) with 58% selectivity to C2+ under visible light. However, the same system leads to high H2 evolution (HER) by increasing the cobalt oxide content, suggesting that the selectivity and preference for the CO2RR or HER depend on oxide decoration. By comparing HER and CO2RR evolution in the same system, this work provides critical insights into the catalytic mechanism, indicating that the CoOx/g-C3N4 heterojunction formation is necessary to foster high visible light photoactivity.

Hypoxia modulates the phenotype of mechanically stressed endothelial cells responding to CoCr-enriched medium.

Given the importance of the endothelial cell phenotype in dental peri-implant healing processes, the aim of this study was to better assess the involvement of endothelial cells responding to cobalt-chromium (CoCr)-enriched medium. Biologically, cobalt is widely used molecule to induce chemical experimental hypoxia because it stabilizes hypoxia inducible factors (HIF1α). The aplication of hypoxia models provides better experimental condition to allow its impact on cellular metabolism, by looking for biochemical and molecular issues. Thus, this study looks for understaing whether CoCr-based materials are able to modulate endothelial cells considering the hypoxic effect prmoted by cobalt. Firstly, our data shows there is a siginificant effect on endothelial phenotype by modulating the expression of VEGF and eNOS genes, whith low requirement of genes related with proteasome intracellular complex. Importantly, the data were validated using classical chemical modulators of hypoxia signaling [chrysin (5,7-dihydroxyflavone) and Dimethyloxalylglycine (DMOG)] in functional assays. Altogether, these data validate the hypothesis that hipoxya is important to maintain the phenotype of endothelial cells, and it is properly interesting during the tissue regeneration surrounding implants and so compromising osseointegration process. Finally, it is important to mention that the cobalt released from CoCr devices might contribute with an sufficient microenvironment surrounding implanted devices and it paviments new roads looking for more bioactive surfaces of implantable materials in human health.

Estudo in vitro de microdeformações ósseas comparando infraestruturas para próteses do tipo protocolo: impacto dos materiais cobalto-cromo e fibra de vidro reforçada com compósito / In vitro study of bone microdeformations comparing infrastructures for protocol-type prostheses: impact of cobalt-chrome materials and fiberglass reinforced with composite

Este estudo investigou a eficácia biomecânica de infraestruturas de próteses feitas de cobalto-cromo (CoCr) e compósito de fibra de vidro (FVRC), implantadas em mandíbulas edêntulas. A distribuição de densidade foi investigada utilizando um modelo ósseo sintético, equipado com extensômetros, para simular condições anatômicas e biomecânicas humanas. Os implantes de conexão interna cone morse fabricados pela Conexão Sistemas de Próteses, Arujá, São Paulo, Brasil, têm diâmetro e comprimento de 4.0mm e 13mm, respectivamente, e os intermediários protéticos selecionados foram Micro Unit Sólidos da mesma marca para plataforma cone morse, com altura de transmucoso 2,5 mm, foram utilizados para suportar as infraestruturas de próteses híbridas. Por meio de extensometria, mediu-se a deformação óssea sob carga ao redor dos quatro implantes, comparando as performances das infraestruturas CoCr e FVRC. Os resultados revelaram informações importantes sobre a seleção de materiais para infraestruturas de próteses, com foco específico nas barras de FVRC e CoCr. Os testes "in vitro" e análises estatísticas destacaram que as barras de FVRC produziram menores microdeformações em comparação com as de CoCr sob carga. Essa diferença foi estatisticamente significativa, indicando que a FVRC possui uma capacidade superior de absorver e distribuir carga de maneira mais eficiente. No entanto, ressalta-se a necessidade de estudos futuros, incluindo pesquisas clínicas, para explorar totalmente as implicações desses achados e aprimorar ainda mais as práticas de reabilitação oral com implantes (AU)

This study investigated the biomechanical effectiveness of prosthetic infrastructures made of cobalt-chromium (CoCr) and fiberglass composite (FGC), implanted in edentulous jaws. The density distribution was investigated using a synthetic bone model, equipped with strain gauges, to simulate human anatomical and biomechanical conditions. The morse cone internal connection implants manufactured by Conexão Sistemas de Próteses, Arujá, São Paulo, Brazil, have a length of 4.0mm and 13mm, respectively, and the prosthetic intermediates selected were Micro Unit Solids of the same brand for a morse cone platform, with a transmucosal height of 2.5 mm, were used to support hybrid prosthetic infrastructures. Using extensometry, bone deformation under load around the four implants was measured, comparing with the performance of the CoCr and FGC infrastructures. The results revealed important information about the selection of materials for prosthetic infrastructures, with a specific focus on FGC and CoCr bars. "In vitro" tests and statistical analyzes highlighted that FGC bars produced smaller microdeformations compared to CoCr bars under load. This difference was statistically significant, demonstrating that FGC has a superior capacity to absorb and distribute load more efficiently. However, the need for future studies, including clinical research, is highlighted to fully explore the implications of these findings and further improve oral rehabilitation practices with implants. (AU)

Antimicrobial activity of cleansers on the cobalt-chromium surface of removable partial denture: a systematic review.

This study aimed to review systematically the literature about the antimicrobial action of evaluated cleansers on the Co-Cr alloy of RPD. The search was conducted in MEDLINE/PubMed, Scopus, Lilacs, Embase and Science Direct May, 2022. The review was performed based on PRISMA guidelines and recorded in Open Science Framework. Independent reviewers performed the search, selection, extraction, and analysis of the data. The risk of bias of the in vitro and clinical trials studies was analyzed by the Joanna Briggs Institute tool. A total of 187 articles were found and 9 were included. The cleansers that showed antimicrobial action were 2% and 5.25% sodium hypochlorite, 0.12% chlorhexidine and NitrAdine effervescent tablet. Polident, Corega Tabs effervescent tablets and 5 mg/mL chitosan solution showed intermediate effects. Propolis and green tea toothpaste were not effective. Three articles presented a high risk of bias and 6, low risk. The cleansers that showed the highest antimicrobial efficacy on Co-Cr alloy were 0.12% chlorhexidine digluconate and NitrAdine and can be safely used on RPD framework.

Treatment of textile wastewater using the Co(II)/NaHCO3/H2O2 oxidation system.

Textile wastewater (TWW) is one of the most hazardous wastewaters for ecosystems when it is discharged directly into water streams without adequate treatment. Some organic pollutants, such as dyes in TWW, are considered refractory compounds that are difficult to degrade using conventional chemical and biological methods. The bicarbonate-activated peroxide (BAP) system is an advanced oxidation process (AOP) based on applying H2O2, which has been demonstrated to be a clean and efficient technology for dye degradation, with the advantage of operating under slightly alkaline pH conditions. In this study, response surface methodology (RSM) based on a central composite design (CCD) was used to optimize the degradation of TWW contaminated with the azo dye Acid Black 194 using the BAP system catalyzed with cobalt ions in solution (Co2+). The analysis of variance (ANOVA) technique was applied to identify significant variables and their individual and interactive effects on the degradation of TWW. The optimum reagent concentrations for degrading TWW at 25 °C and with 45 µM Co2+ were 787.61 and 183.34 mM for H2O2 and NaHCO3, respectively. Under these conditions, complete decolorization (≥99.40), 32.20 % mineralization, and 52.02 % chemical oxygen demand removal were achieved. Additionally, the acute toxicity of textile wastewater before and after oxidation was evaluated with guppy fish (Poecilia reticulata), showing a total reduction in mortality after treatment with the Co2+-BAP system. The Co2+-BAP oxidation system is a potential method for textile wastewater treatment, which, in addition to achieving complete decolorization and partial mineralization, improves biodegradability and reduces the toxicity of the treated water.

Antifungal activity of Co(II) and Cu(II) complexes containing 1,3-bis(benzotriazol-1-yl)-propan-2-ol on the growth and virulence traits of fluconazole-resistant Candida species: synthesis, DFT calculations, and biological activity.

Relevant virulence traits in Candida spp. are associated with dimorphic change and biofilm formation, which became an important target to reduce antifungal resistance. In this work, Co(II) complexes containing a benzotriazole derivative ligand showed a promising capacity of reducing these virulence traits. These complexes exhibited higher antifungal activities than the free ligands against all the Candida albicans and non-albicans strains tested, where compounds 2 and 4 showed minimum inhibitory concentration values between 15.62 and 125 µg mL-1. Moreover, four complexes (2-5) of Co(II) and Cu(II) with benzotriazole ligand were synthesized. These compounds were obtained as air-stable solids and characterized by melting point, thermogravimetric analysis, infrared, Raman and ultraviolet/visible spectroscopy. The analysis of the characterization data allowed us to identify that all the complexes had 1:1 (M:L) stoichiometries. Additionally, Density Functional Theory calculations were carried out for 2 and 3 to propose a probable geometry of both compounds. The conformer Da of 2 was the most stable conformer according to the Energy Decomposition Analysis; while the conformers of 3 have a fluxional behavior in this analysis that did not allow us to determine the most probable conformer. These results provide an important platform for the design of new compounds with antifungal activities and the capacity to attack other target of relevance to reduce antimicrobial resistance.

Effect of electrical and chemical (activation versus inactivation) stimulation of the infralimbic division of the medial prefrontal cortex in rats with chronic neuropathic pain.

Neuropathic pain (NP) represents a complex disorder with sensory, cognitive, and emotional symptoms. The medial prefrontal cortex (mPFC) takes critical regulatory roles and may change functionally and morphologically during chronic NP. There needs to be a complete understanding of the neurophysiological and psychopharmacological bases of the NP phenomenon. This study aimed to investigate the participation of the infralimbic division (IFL) of the mPFC in chronic NP, as well as the role of the N-methyl-D-aspartic acid receptor (NMDAr) in the elaboration of chronic NP. Male Wistar rats were submitted to the von Frey and acetone tests to assess mechanical and cold allodynia after 21 days of chronic constriction injury (CCI) of the sciatic nerve or Sham-procedure ("false operated"). Electrical neurostimulation of the IFL/mPFC was performed by low-frequency stimuli (20 µA, 100 Hz) applied for 15 s by deep brain stimulation (DBS) device 21 days after CCI. Either cobalt chloride (CoCl2 at 1.0 mM/200 nL), NMDAr agonist (at 0.25, 1.0, and 2.0 nmol/200 nL) or physiological saline (200 nL) was administered into the IFL/mPFC. CoCl2 administration in the IFL cortex did not alter either mechanical or cold allodynia. DBS stimulation of the IFL cortex decreased mechanical allodynia in CCI rats. Chemical stimulation of the IFL cortex by an NMDA agonist (at 2.0 nmol) decreased mechanical allodynia. NMDA at any dose (0.25, 1.0, and 2.0 nmol) reduced the flicking/licking duration in the cold test. These findings suggest that the IFL/mPFC and the NMDAr of the neocortex are involved in attenuating chronic NP in rats.

Coordination chemistry applied to anti-doping analysis: Cobalt quantification as its diethyldithiocarbamate complex by liquid chromatography coupled to high resolution tandem mass spectrometry.

Cobalt was included on the World Anti-Doping Agency Prohibited List in 2015 due to its effect on stimulus of erythropoiesis via stabilization of hypoxia-inducible factor. Although it has proven benefits for performance enhancement, the unavailability of inductively coupled plasma-mass spectrometry on routine of the accredited laboratories is a factor that reduces its applicability in anti-doping analysis. Therefore, an analytical method for quantification of urinary cobalt as its diethyldithiocarbamate complex by liquid chromatography coupled with high-resolution tandem mass spectrometry was developed and validated. Palladium was proposed as internal standard and rhodium as a complexation control. A microwave-assisted acid digestion of the urine samples was essential, not only to eliminate the matrix effect but mainly to avoid the non-specific bond of cobalt to endogenous molecules. A linear method was obtained over the studied range from a negative urine control to a spiked concentration of 25 ng/mL, with an estimated limit of quantification of 2.5 ng/mL, and an adequate combined standard uncertainty of 11.4%. Considering that all reagents are commercially available, the proposed strategy is feasible to be included on routine sample preparation. Monitoring urinary cobalt concentrations globally opens the perspective to support the anti-doping system to define a suitable threshold value and to understand its potential misuse by athletes seeking for performance improvement.

Adaptación marginal e interna de cofias fabricadas por métodos convencionales, CAD/CAM de fresado y sinterizado por láser / Marginal and internal adaptation of copings manufactured by conventional methods, CAD/CAM milling and laser sintering

Introducción: la adaptación marginal e interna de nuestras restauraciones fabricadas por fundición sistemas de fresado y sinterización láser es uno de los factores clínicos más importantes para el éxito de las prótesis fijas, previniendo el riesgo de microfiltración y enfermedad periodontal. Objetivo: evaluar la adaptación marginal e interna de cofias metálicas en aleación Cr-Co confeccionadas por técnicas convencionales, CAD/ CAM de fresado y sinterizado por láser. Material y métodos: estudio de tipo experimental, comparativo e in vitro. Se imprimió un modelo maestro en Cr-Co, proveniente del escaneo de un premolar preparado para corona completa, sobre el cual se diseñaron 30 cofias divididas en tres grupos: el primero que corresponde al grupo cofias fundidas fresadas en disco de cera A (A = 10), el segundo grupo cofias fresadas en disco de metal presinterizado B (B = 10) y el tercer grupo cofias impresas por sinterización láser C (C = 10). Se empleó la réplica de silicona, colocando silicona al interior de cada cofia, sobre el modelo maestro, simulando al cemento, mediante una máquina de ensayo universal se realizó una compresión de 50 N. Luego de retirar cada cofia se rellenaron con silicona pesada de adición, obteniendo una réplica de silicona. Se efectuaron dos cortes transversales en sentido vestíbulolingual y mesiodistal. Se observó el espesor de silicona VPS (vinil poliéter silicona) mediante un estereomicroscopio (Nikon SMZ745T), obteniendo valores en micrómetros. Para el análisis estadístico se utilizó el software SPSS 25 con el fin de realizar la prueba de normalidad y ANOVA de dos vías bajo un nivel de confianza del 95%. Resultados: el menor gap lo obtuvo el grupo de fresadas, seguido de las impresas y por último las fundidas por métodos convencionales. ANOVA de dos vías reveló diferencias estadísticamente significativas entre los tres grupos (p < 0.0001). Conclusiones: se encontró que el gap varía con cada método de fabricación, la técnica convencional de fundido mostró un mayor gap, ninguna excediendo el rango clínicamente aceptable (AU)

Introduction: the marginal and internal adaptation of our restorations manufactured by casting, milling systems and laser sintering is one of the most important clinical factors for the success of fixed prostheses, preventing the risk of microleakage and periodontal disease. Objective: evaluate the marginal and internal adaptation of metal copings in Cr-Co alloy made by conventional techniques, CAD/CAM milling and laser sintering. Material and methods: an experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown. An experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown, on which 30 caps divided into three groups were designed; the first group corresponds to the cast copings milled on a wax disc A (A = 10), the second group milled copings on a presintered metal disc B (B = 10) and the third group printed by laser sintering copings C (C = 10). The silicone replica was used, placing silicone inside each coping, on the master model, simulating cement, using a universal testing machine, a 50 N compression was performed. After removing each coping, they were filled with heavy addition silicone, obtaining a silicone replica. Two cross-sections were made in the buccolingual and mesiodistal direction., observing the thickness of the VPS (vinyl polyeter silicone) silicone using a stereomicroscope (Nikon SMZ745T), obtaining values in micrometers. For the statistical analysis, the SPSS 25 software was used in order to perform the normality and two-way ANOVA tests under a 95% confidence level. Results: the smallest gap was obtained by the milled group, followed by the printed ones and finally those cast by conventional methods. Two-way ANOVA revealed statistically significant differences between the three groups (p < 0.0001). Conclusions: the gap was found to vary with each fabrication method, the conventional casting technique showed a larger gap, none exceeding the clinically acceptable range (AU)

Inducing Magnetic Properties with Ferrite Nanoparticles in Resins for Additive Manufacturing.

Additive manufacturing and nanotechnology have been used as fundamental tools for the production of nanostructured parts with magnetic properties, expanding the range of applications in additive processes through tank photopolymerization. Magnetic cobalt ferrite (CoFe2O4) and barium ferrite (BaFe12O19) nanoparticles (NPs) with an average size distribution value (DTEM) of 12 ± 2.95 nm and 37 ± 12.78 nm, respectively, were generated by the hydroxide precipitation method. The dispersion of the NPs in commercial resins (Anycubic Green and IRIX White resin) was achieved through mechanochemical reactions carried out in an agate mortar for 20 min at room temperature, with limited exposure to light. The resulting product of each reaction was placed in amber vials and stored in a box to avoid light exposure. The photopolymerization process was carried out only at low concentrations (% w/w NPs/resin) since high concentrations did not result in the formation of pieces, due to the high refractive index of ferrites. The Raman spectroscopy of the final pieces showed the presence of magnetic NPs without any apparent chemical changes. The electron paramagnetic resonance (EPR) results of the pieces demonstrated that their magnetic properties were maintained and not altered during the photopolymerization. Although significant differences were observed in the dispersion process of the NPs in each piece, we determined that the photopolymerization did not affect the structure and superparamagnetic behavior of ferrite NPs during processing, successfully transferring the magnetic properties to the final 3D-printed piece.

Organo-Functionalized Lacunary Double Cubane-Type Oxometallates: Synthesis, Structure, and Properties of [(MII Cl)2 (VIV O)2 {((HOCH2 CH2 )(H)N(CH2 CH2 O))(HN(CH2 CH2 O)2 )}2 ] (M=Co, Zn).

Organofunctionalized tetranuclear clusters [(MII Cl)2 (VIV O)2 {((HOCH2 CH2 )(H)N(CH2 CH2 O))(HN(CH2 CH2 O)2 )}2 ] (1, M=Co, 2: M=Zn) containing an unprecedented oxometallacyclic {M2 V2 Cl2 N4 O8 } (M=Co, Zn) framework have been prepared by solvothermal reactions. The new oxo-alkoxide compounds were fully characterized by spectroscopic methods, magnetic susceptibility measurement, DFT and ab initio computational methods, and complete single-crystal X-ray diffraction structure analysis. The isostructural clusters are formed of edge-sharing octahedral {VO5 N} and trigonal bipyramidal {MO3 NCl} units. Diethanolamine ligates the bimetallic lacunary double cubane core of 1 and 2 in an unusual two-mode fashion, unobserved previously. In the crystalline state, the clusters of 1 and 2 are joined by hydrogen bonds to form a three-dimensional network structure. Magnetic susceptibility data indicate weakly antiferromagnetic interactions between the vanadium centers [Jiso (VIV -VIV )=-5.4(1); -3.9(2) cm-1 ], and inequivalent antiferromagnetic interactions between the cobalt and vanadium centers [Jiso (VIV -CoII )=-12.6 and -7.5 cm-1 ] contained in 1.

Materials Based on Co, Cu, and Cr as Activators of PMS for Degrading a Representative Antibiotic-The Strategy for Utilization in Water Treatment and Warnings on Metal Leaching.

A chromate of copper and cobalt (Φy) was synthesized and characterized. Φy activated peroxymonosulfate (PMS) to degrade ciprofloxacin (CIP) in water. The Φy/PMS combination showed a high degrading capability toward CIP (~100% elimination in 15 min). However, Φy leached cobalt (1.6 mg L-1), limiting its use for water treatment. To avoid leaching, Φy was calcinated, forming a mixed metal oxide (MMO). In the combination of MMO/PMS, no metals leached, the CIP adsorption was low (<20%), and the action of SO4•- dominated, leading to a synergistic effect on pollutant elimination (>95% after 15 min of treatment). MMO/PMS promoted the opening and oxidation of the piperazyl ring, plus the hydroxylation of the quinolone moiety on CIP, which potentially decreased the biological activity. After three reuse cycles, the MMO still presented with a high activation of PMS toward CIP degradation (90% in 15 min of action). Additionally, the CIP degradation by the MMO/PMS system in simulated hospital wastewater was close to that obtained in distilled water. This work provides relevant information on the stability of Co-, Cu-, and Cr-based materials under interaction with PMS and the strategies to obtain a proper catalyst to degrade CIP.

Efficient removal of veterinary drugs from aqueous solutions using magnetically separable carbonaceous materials derived from cobalt and iron metal-organic frameworks.

Rapid synthesis of carbon-based magnetic materials derived from cobalt and iron metal-organic frameworks (MOFs), ZIF-67, and MIL-100(Fe), by microwave-assisted method, followed by carbonization under a N2 atmosphere is described in this study. The carbon-derived MOFs (CDMs) were evaluated for the removal of the emerging pollutants sulfadiazine (SDZ) and flumequine (FLU) used as veterinary drugs. The study aimed to link the adsorption behavior with their surface properties and elemental composition. C-ZIF-67 and C-MIL-100(Fe) showed hierarchical porous structures with specific surface areas of 295.6 and 163.4 m2 g-1, respectively. The Raman spectra of the CDMs show the characteristic D and G bands associated with defect-rich carbon and sp2 graphitic carbon, respectively. The CDMs exhibit cobalt species (Co3O4, CoO, and Co) in C-ZIF-67 and iron species (Fe2O3, Fe3O4, and Fe) in C-MIL-100 (Fe) which are related to the magnetic behavior of CDMs. C-ZIF-67 and C-MIL-100 (Fe) had saturation magnetization values of 22.9 and 53.7 emu g-1, respectively, allowing easy solid-liquid separation using a magnet. SDZ and FLU removal rates on CDMs follow pseudo-second-order kinetics, and adsorption isotherms fit the Langmuir model based on regression coefficient values. Adsorption thermodynamics calculations showed that the adsorption of SDZ and FLU by CDMs was a thermodynamically favorable process. Therefore, these properties of C-ZIF-67 and C-MIL-100 (Fe) and their regeneration ability facilitate their use as adsorbents for emerging pollutants.

Bio-sorbent from castor oil polyurethane foam containing cellulose-halloysite nanocomposite for removal of manganese, nickel and cobalt ions from water.

In order to mitigate the contamination of water with heavy metals, caused by mining dam failures in Brumadinho and Mariana in Brazil, eco-friendly bio-based castor oil polyurethane foams, containing a cellulose-halloysite green nanocomposite were prepared. Polyurethane foams containing none (PUF-0), 5%wt (PUF-5), and 10%wt (PUF-10) of the nanocomposite were obtained. The application of the material in aqueous media was verified through an investigation of the efficiency of adsorption, the adsorption capacity, and the adsorption kinetics in pH= 2 and pH= 6.5 for manganese, nickel, and cobalt ions. An increase of 5.47 times in manganese adsorption capacity was found after only 30 min in contact with a solution having this ion at pH= 6.5 for PUF-5 and 11.38 times for PUF-10 when both were compared with PUF-0. Adsorption efficiency was respectively 68.17% at pH= 2 for PUF-5% and 100% for PUF-10 after 120 h, while for the control foam, PUF-0, the adsorption efficiency was only 6.90%.

Scratch and Wear Behaviour of Co-Cr-Mo Alloy in Ringer's Lactate Solution.

Cobalt-chromium-molybdenum (Co-Cr-Mo) alloy is a material recommended for biomedical implants; however, to be suitable for this application, it should have good tribological properties, which are related to grain size. This paper investigates the tribological behaviour of a Co-Cr-Mo alloy produced using investment casting, together with electromagnetic stirring, to reduce its grain size. The samples were subjected to wear and scratch tests in simulated body fluid (Ringer's lactate solution). Since a reduction in grain size can influence the behaviour of the material, in terms of resistance and tribological response, four samples with different grain sizes were produced for use in our investigation of the behaviour of the alloy, in which we considered the friction coefficient, wear, and scratch resistance. The experiments were performed using a tribometer, with mean values for the friction coefficient, normal load, and tangential force acquired and recorded by the software. Spheres of Ti-6Al-4V and 316L steel were used as counterface materials. In addition, to elucidate the influence of grain size on the mechanical properties of the alloy, observations were conducted via scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD). The results showed changes in the structure, with a reduction in grain size from 5.51 to 0.79 mm. Using both spheres, the best results for the friction coefficient and wear volume corresponded to the sample with the smallest grain size of 0.79 mm. The friction coefficients obtained were 0.37 and 0.45, using the Ti-6Al-4V and 316L spheres, respectively. These results confirm that the best surface finish for Co-Cr-Mo alloy used as a biomedical implant is one with a smaller grain size, since this results in a lower friction coefficient and low wear.

Epigenetic Differences Arise in Endothelial Cells Responding to Cobalt-Chromium.

Cobalt-chromium (Co-Cr)-based alloys are emerging with important characteristics for use in dentistry, but the knowledge of epigenetic mechanisms in endothelial cells has barely been achieved. In order to address this issue, we have prepared a previously Co-Cr-enriched medium to further treat endothelial cells (HUVEC) for up to 72 h. Our data show there is important involvement with epigenetic machinery. Based on the data, it is believed that methylation balance in response to Co-Cr is finely modulated by DNMTs (DNA methyltransferases) and TETs (Tet methylcytosine dioxygenases), especially DNMT3B and both TET1 and TET2. Additionally, histone compaction HDAC6 (histone deacetylase 6) seems to develop a significant effect in endothelial cells. The requirement of SIRT1 seems to have a crucial role in this scenario. SIRT1 is associated with a capacity to modulate the expression of HIF-1α in response to hypoxia microenvironments, thus presenting a protective effect. As mentioned previously, cobalt is able to prevent HIF1A degradation and maintain hypoxia-related signaling in eukaryotic cells. Together, our results show, for the first time, a descriptive study reporting the relevance of epigenetic machinery in endothelial cells responding to cobalt-chromium, and it opens new perspectives to better understand their repercussions as prerequisites for driving cell adhesion, cell cycle progression, and angiogenesis surrounding this Co-Cr-based implantable device.

Multiplication, morphogenesis and foliar abscision of Schinopsis brasiliensis Engl. in vitro / Multiplicación, morfogénesis y abscisión foliar de Schinopsis brasiliensis Engl. in vitro

The objective was to evaluate plant growth regulators and ethylene inhibitors on the development and leaf abscission of Schinopsis brasiliensis Engl. Zeatin (ZEA) was evaluated in concentrations combined with concentrations of indolacetic acid (IAA), naphthalene acetic acid (NAA) and indolbutyric acid (IBA). ZEA and 6-benzylamino purine (BAP) were evaluated in concentrations plus a control. Ethylene inhibitors, silver nitrate and cobalt chloride were evaluated in four concentrations. The addition of 0.2 µL-1 of NAA to 0.4 µL-1 of ZEA promotes a greater number of baraúna sprouts. At concentrations of 5 and 10 µM, cobalt chloride is more efficient than silver nitrate for reducing leaf abscission in baraúna. IAA is the most suitable auxin to be associated with ZEA for higher shoot length and number of buds. Silver nitrate from a concentration of 20 µM completely avoids leaf abscission whilecobalt chloride has a maximum reduction in abscission at a concentration of 40 µM.

El objetivo fue evaluar reguladores de crecimiento e inhibidores de etileno sobre el desarrollo y abscisión foliar en Schinopsis brasiliensis Engl. La zeatina (ZEA) se evaluó en concentraciones combinadas con concentraciones de ácido indolacético (IAA), ácido naftaleno acético (NAA) y ácido indolbutírico (IBA). Se evaluaron ZEA y 6-bencilamino purina (BAP) en concentraciones más un control. Se evaluaron inhibidores de etileno, nitrato de plata y cloruro de cobalto, en cuatro concentraciones. La adición de 0.2 µL-1 de NAA a 0.4 µL-1 de ZEA promueve un mayor número de brotes de baraúna. A concentraciones de 5 y 10 µM, el cloruro de cobalto es más eficaz que el nitrato de plata para reducir la abscisión de las hojas en baraúna. IAA es la auxina más adecuada para asociar con ZEA para una mayor longitud de brotes y número de brotes. El nitrato de plata a partir de una concentración de 20 µM evita completamente la abscisión de las hojas, mientras que el cloruro de cobalto tiene una reducción máxima en la abscisión a una concentración de 40 µM.