The emerging chemistry of self-electrified water interfaces.

Water is known for dissipating electrostatic charges, but it is also a universal agent of matter electrification, creating charged domains in any material contacting or containing it. This new role of water was discovered during the current century. It is proven in a fast-growing number of publications reporting direct experimental measurements of excess charge and electric potential.

Water Reactivity in Electrified Interfaces: The Simultaneous Production of Electricity, Hydrogen, and Hydrogen Peroxide at Room Temperature.

Hygroelectric cells deliver hydrogen, hydrogen peroxide, and electric current simultaneously at room temperature from liquid water or vapor. Different cell arrangements allowed the electrical measurements and the detection and measurement of the reaction products by two methods each. Thermodynamic analysis shows that water dehydrogenation is a non-spontaneous reaction under standard conditions, but it can occur within an open, non-electroneutral system, thus supporting the experimental results.

Photodynamic inactivation of different Candida species and inhibition of biofilm formation induced by water-soluble porphyrins.

Background: Candida spp. is the main fungal genus related to infections in humans, and its treatment has become a challenge due to the production of biofilm and its resistance/multi-resistance profile to conventional antifungals. Antimicrobial photodynamic therapy stands out as a treatment characterized by a broad spectrum of antimicrobial action, being able to induce oxidative stress in pathogens, and porphyrins are photosensitizers with high selectivity to pathogens.

Antimicrobial activity of water-soluble tetra-cationic porphyrins on Pseudomonas aeruginosa.

This manuscript presents the cytotoxicity, antimicrobial activity, antibiofilm preliminary properties, and associated therapy with commercial drugs using water-soluble tetra-cationic porphyrins against Pseudomonas aeruginosa. Two commercial tetra-cationic porphyrins were tested against a standard strain of P. aeruginosa 01 (PA01) in antibacterial activity assays under dark conditions and irradiated with white light for 120 min.

In vitro porphyrin-based photodynamic therapy against mono and polyculture of multidrug-resistant bacteria isolated from integumentary infections in animals.

Multidrug-resistant (MDR) organisms have been frequently isolated from integumentary lesions of animals, and these lesions are usually infected by more than one pathogen. This study evaluated an in vitro antimicrobial photodynamic therapy (aPDT) using two water-soluble tetra-cationic porphyrins (3-HTMeP and 4-HTMeP) against mono and polyculture of MDR bacteria isolated from dogs, cats, and horses. Ten isolates of MDR bacteria (two of each species: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus pseudointermedius) were used to evaluate aPDT against the monoculture using a non-cytotoxic concentration of 3-HTMeP and 4-HTMeP porphyrins (40 µM), with 30 min of light irradiation in Gram-positive and 90 min for Gram-negative bacteria.

AFM advanced modes for dental and biomedical applications.

Several analytical methods have been employed to elucidate bonding mechanisms between dental hard tissues, luting agents and restorative materials. Atomic Force Microscopy (AFM) imaging that has been extensively used in materials science, but its full capabilities are poorly explored by dental research community. In fact, commonly used to obtain topographic images of different surfaces, it turns out that AFM is an underestimated technique considering that there are dozens of basic and advanced modes that are scarcely used to explain properties of biomaterials.

Simulation of CAD/CAM milling on lithium disilicate: Mechanical and topographic analyses of surface grinding different protocols.

The aim of this study was to evaluate the topography and the fatigue performance of lithium disilicate glass-ceramic after surface grinding through different laboratory protocols used to simulate the Computer-aided design/Computer-aided manufacturing (CAD/CAM) milling. Ceramic discs (IPS e.max CAD, Ø = 13.

Nanomolar effective report of tetra-cationic silver(II) porphyrins against non-tuberculous mycobacteria in antimicrobial photodynamic approaches.

We report the photoinactivation evaluation of Ag(II) porphyrins (cationic AgTMeP and anionic AgTPPS) in the antimicrobial photodynamic therapy (aPDT) of rapidly growing mycobacterial strains. The aPDT assays in the Mycolicibacterium fortuitum, Mycobacteroides abscessus subs. abscessus, Mycobacteroides abscessus subsp.

Hybrid polymer aerogels containing porphyrins as catalysts for efficient photodegradation of pharmaceuticals in water.

Polymer aerogels of poly(acrylic acid)/poly(vinyl alcohol) (labeled as CPA) were prepared and tested as support materials for different cationic porphyrin organocatalysts (denoted as TMPyP, TMPyPZn, or TMPyPMn). The hybrid aerogels were characterized by various techniques, while their catalytic activity was investigated towards the photodegradation of amoxicillin (AMX), caffeine (CAF), and naproxen (NPX) under artificial visible light. Photodegradation experiments revealed that the CPA-TMPyPMn aerogel shows superior catalytic potential when compared to the others aerogels or the "free" TMPyPMn porphyrin.

Electromechanical coupling in elastomers: a correlation between electrostatic potential and fatigue failure.

The recent discovery of electromechanical coupling in elastomers showed periodic electrification in phase with rubber stretching but following different electrostatic potential patterns. In this work, a Kelvin electrode monitored silicone and natural rubber electrification for extended periods until the rubber tubing underwent rupture. The electric potential of the rubber follows regular, quasi-sinusoidal patterns at the beginning and during the whole run, except when close to rubber fatigue failure, changing into complex waveforms.

Photo-damage promoted by tetra-cationic palladium(II) porphyrins in rapidly growing mycobacteria.

Antimicrobial photodynamic therapy (aPDT) has gained prominence in microbiology, especially in treating non-invasive infections. Diseases such as mycobacteriosis, which causes localized infections and has a slow treatment, tend to be future targets for this type of technology. Therefore, this study aimed to explore the action of two isomeric Pd(II)-porphyrins on fast-growing mycobacterial strains (RGM).

Metal center ion effects on photoinactivating rapidly growing mycobacteria using water-soluble tetra-cationic porphyrins.

Rapidly growing mycobacteria (RGM) are pathogens that belong to the mycobacteriaceae family and responsible for causing mycobacterioses, which are infections of opportunistic nature and with increasing incidence rates in the world population. This work evaluated the use of six water-soluble cationic porphyrins as photosensitizers for the antimicrobial photodynamic therapy (aPDT) of four RGM strains: Mycolicibacterium fortuitum, Mycolicibacterium smeagmatis, Mycobacteroides abscessus subs. Abscessus, and Mycobacteroides abscessus subsp.

Peripheral tetra-cationic Pt(II) porphyrins photo-inactivating rapidly growing mycobacteria: First application in mycobacteriology.

In this manuscript, we report, for the first time, the photoinactivation evaluation of tetra-cationic porphyrins with peripheral Pt (II)-bpy complexes in the photodynamic inactivation (PDI) of rapidly growing mycobacterial strains (RGM). Two different isomeric Pt (II)-porphyrins were synthetized and applied. PDI experiments in the strains of Mycobacteroides abscessus subsp.

Stable Resin Bonding to Y-TZP Ceramic with Air Abrasion by Alumina Particles Containing 7% Silica.

Purpose: To evaluate the influence of new air-abrasion powders with different silica concentrations (silica-coated aluminum oxide) and aging on the bond strength between composite cement and Y-TZP ceramic.

Materials And Methods: Ceramic slices (7 x 6.3 x 2 mm3) were randomly allocated into 8 groups (n = 20) considering different surface treatments (SiC: silica-coated aluminum oxide particles; AlOx: aluminum oxide particles; 7% Si and 20% Si: experimental powders consisting of 7% and 20% silica-coated of AlOx respectively) and aging (baseline: 24 h at 37°C in water; aged: 90 days at 37°C in water + 12,000 thermal cycles).

Removal of fluoride from fertilizer industry effluent using carbon nanotubes stabilized in chitosan sponge.

Adsorption of fluoride from fertilizer industry effluent using carbon nanotubes stabilized in chitosan sponge as adsorbent was evaluated. The effluent was produced in the washing of acid gases during the reaction in fertilizer production and all assays were performed using this hazardous material. Adsorbent characterization and ions interactions were elucidated from differential scanning calorimetry, thermal gravimetric analyses, X-ray diffraction, scanning electron microscopy dispersive energy X-ray spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy.

Materials from renewable resources: new properties and functions.

Sustainable production requires increasing use of raw materials from renewable sources, processed under mild conditions with minimal effluent production. These requirements are satisfied by using materials derived from biomass, in synergy with food and energy production. The possibilities of biomass are continuously enlarged by new findings, as in the intrinsic nanocomposite properties of natural rubber and the amphiphile behavior of cellulose that translated into new functional materials, including high-performance, flexible and conductive non-metallic materials.

Microstructure, topography, surface roughness, fractal dimension, internal and marginal adaptation of pressed and milled lithium-disilicate monolithic restorations.

Purpose: To characterize the effect of two processing techniques (pressing and CAD/CAM - Computer Aided Design/Computer Aided Machining) of lithium-disilicate (LD) based crowns on the microstructure, topography, roughness, fractal dimension, internal and marginal adaptation.

Methods: One-hundred identical preparations for monolithic crowns were made with dentin analogue material (G10 epoxy resin). One of the preparations was scanned and a monolithic crown in lithium-disilicate was planned in the CAD system.

Conduction and Excess Charge in Silicate Glass/Air Interfaces.

The glass/air interface shows electrical properties that are unexpected for a widely used electrical insulator. The mobility of interfacial charge carriers under 80% relative humidity (RH) is 4.81 × 10 m s V, 3 orders of magnitude higher than the electrophoretic mobility of simple ions in water and less than 2 orders of magnitude lower than the electron mobility in copper metal.

Towards superlubricity in nanostructured surfaces: the role of van der Waals forces.

Hydrogenated amorphous carbon (a-C:H) thin films have a unique combination of properties that are fundamental in mechanical and electromechanical devices aimed at energy efficiency issues. The literature brings a wealth of information about the ultra-low friction (superlubricity) mechanism in a-C:H thin films. However, there is persistent controversy concerning the physicochemical mechanisms of contact mechanics at the atomic/molecular level and the role of electrical interactions at the sliding interface is still a matter of debate.

Hydrofluoric acid concentrations: Effect on the cyclic load-to-failure of machined lithium disilicate restorations.

Objectives: To evaluate the effects of the etching with different hydrofluoric acid (HF) concentrations on the cyclic load-to-failure (C) of machined lithium disilicate crowns cemented to dentin analogue material.

Methods: Pairs of dentin analogue prosthetic preparations and lithium disilicate ceramic crowns with simplified and standardized designs were machined (n=18). The preparations were etched with 10% HF (60s), followed by primer application.

Electricity on Rubber Surfaces: A New Energy Conversion Effect.

This work describes the conversion of mechanical energy to electricity, by periodically stretching rubber tubing and allowing it to relax. The rubber surface shows periodic and reversible electrostatic potential variations, in phase with the tubing length. The potential change depends on the elastomer used: silicone loses charge when stretched and becomes strongly negative when relaxed, whereas the stretched natural rubber is positive, becoming negative when relaxed.

Bipolar tribocharging signal during friction force fluctuations at metal-insulator interfaces.

Friction and triboelectrification of materials show a strong correlation during sliding contacts. Friction force fluctuations are always accompanied by two tribocharging events at metal-insulator [e.g.

Friction coefficient dependence on electrostatic tribocharging.

Friction between dielectric surfaces produces patterns of fixed, stable electric charges that in turn contribute electrostatic components to surface interactions between the contacting solids. The literature presents a wealth of information on the electronic contributions to friction in metals and semiconductors but the effect of triboelectricity on friction coefficients of dielectrics is as yet poorly defined and understood. In this work, friction coefficients were measured on tribocharged polytetrafluoroethylene (PTFE), using three different techniques.

Antiadhesive and antibacterial multilayer films via layer-by-layer assembly of TMC/heparin complexes.

N-Trimethyl chitosan (TMC), an antibacterial agent, and heparin (HP), an antiadhesive biopolymer, were alternately deposited on modified polystyrene films, as substrates, to built antiadhesive and antibacterial multilayer films. The properties of the multilayer films were investigated by Fourier transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy, and Kelvin force microscopy. In vitro studies of controlled release of HP were evaluated in simulated intestinal fluid and simulated gastric fluid.