Preliminary Approaches to Cosmeceuticals Emulsions Based on N-ProlylPalmitoyl Tripeptide-56 Acetat-Bakuchiol Complex Intended to Combat Skin Oxidative Stress.

This study focuses on the development of a performant formulation for O/W dermato-cosmetic emulsions, which can be incorporated into novel dermato-cosmetic products or used as such. The O/W dermato-cosmetic emulsions contain an active complex based on a plant-derived monoterpene phenol, bakuchiol (BAK) and a signaling peptide named n-prolyl palmitoyl tripeptide-56 acetate (TPA). As a dispersed phase, we used a mix of vegetable oils, and as a continuous phase, Rosa damascena hydrosol was employed. Three emulsions containing different concentrations of the active complex were formulated (0.5% BAK + 0.5% TPA = E.1.1., 1% BAK + 1%TPA = E.1.2., 1% BAK + 2% TPA = E.1.3.). Stability testing was performed through sensory analysis, stability after centrifugation, conductivity and optical microscopy. A preliminary in vitro study regarding the diffusion ability of antioxidants through chicken skin was also undertaken. DPPH and ABTS assays were used to highlight the optimal concentration and combination in the formulation in terms of antioxidant properties and safety level of the active complex (BAK/TPA). Our results showed that the active complex used for preparing emulsions with BAK and TPA showed good antioxidant activity and is suitable for obtaining topical products with potential antiaging effects.

Biosorbent Based on Poly(vinyl alcohol)-Tricarboxi-Cellulose Designed to Retain Organic Dyes from Aqueous Media.

Methylene Blue, a cationic dye, was retained from aqueous solutions using a novel biosorbent made of poly(vinyl alcohol) reticulated with tricarboxi-cellulose produced via TEMPO oxidation (OxC25). The study of the Methylene Blue biosorption process was performed with an emphasis on operational parameters that may have an impact on it (such as biosorbent concentration, pH of the aqueous media, and temperature). The current study focused on three areas: (i) the physic-chemical characterization of the biosorbent (scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX)); (ii) biosorption data modeling to determine the quantitative characteristic parameters employing three equilibrium isotherms (Langmuir, Freundlich, and Dubinin-Radushkevich-DR); and (iii) the study of temperature influence. The results of the study showed that the Langmuir model provided a good fit for the experimental data of biosorption, realizing a maximum capacity of 806.45 mg/g at 20 °C. The free energy of biosorption (E) evaluated by the DR equation was in the range of 6.48-10.86 KJ/mol. The values of the thermodynamic parameters indicated an endothermic process because the free Gibbs energy ranged from -9.286 KJ/mol to -2.208 KJ/mol and the enthalpy was approximately -71.686 KJ/mol. The results obtained encourage and motivate the further study of this biosorption process by focusing on its kinetic aspects, establishing the biosorption's controlled steps, identifying the mechanism responsible for the retention of textile dyes presented in moderate concentration in aqueous media, and studying the biosorption process in a dynamic regime with a view to applying it to real systems.

Microstructural, Corrosion Resistance, and Tribological Properties of Al2O3 Coatings Prepared by Atmospheric Plasma Spraying.

An usual material, EN-GJL-250 cast iron, used for automotive braking systems, was covered with a ceramic material (105NS-1 aluminium oxide) using an industrial deposition system (Sulzer Metco). The main reason was to improve the corrosion and wear (friction) resistance properties of the cast-iron. Samples were prepared by mechanical grinding and sandblasting before the deposition. We applied two and four passes (around 12-15 µm by layer) each at 90° obtaining ceramic coatings of 30 respectively 60 µm. The surface of the samples (with ceramic coatings) was investigated using scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and X-ray diffraction (XRD). Scratch and micro-hardness tests were performed using CETR-UMT-2 micro-tribometer equipment. The better corrosion resistance of the base material was obtained by applying the ceramic coating. The results present a better corrosion resistance and a higher coefficient of friction of the coated samples.

On the Deposition Process of Ceramic Layer Thin Films for Low-Carbon Steel Pipe Protection.

Ceramic thin films with variable thicknesses have been used in many applications. In order to protect the petroleum transportation pipes against the harmful H2S action, two ceramic materials as thin layers are proposed. In this article, pulsed laser deposition (PLD) of ceramic layers by in situ time-resolved optical techniques is investigated. Two ceramic materials were used as targets and real-time monitoring of the PLD process was realized via ICCD fast camera imaging and optical emission spectroscopy. The space-time displacement of the ceramic emissions was analyzed in order to determine the plasma structure and respective kinetic energies. Spectral-resolved investigation allowed the determination of plasma species individual velocities (in the first case: 43 km/s for C ionic species, 11 km/s for Si, from 25 to 5 km/s for atomic species; in the second case: 32 km/s for C ionic species, 11 km/s for W species, and 15 and 53 km/s for neutral species). SEM and AFM techniques were implemented to analyze the resulting ceramic layers showing homogeneous surfaces with characteristic material droplets. The ablation crater also reveals selective ablation during the deposition process. EDX results show that Al/Si is retained in the thin films similar to the target composition.

Biosorbents Based on Biopolymers from Natural Sources and Food Waste to Retain the Methylene Blue Dye from the Aqueous Medium.

The use of a biosorbent based on residual biomass from brewing industry (Saccharomyces pastorianus) immobilized in a natural biopolymer (sodium alginate) was investigated for Methylene Blue removal from aqueous medium. Saccharomyces pastorianus, immobilized by a simple entrapment technique and by microencapsulation in alginate was characterized using SEM, EDAX, pHPZC and the biosorption behavior toward organic pollutant, such as cationic dye. The biosorption experiments were studied by assessing, in a first stage, the influence of the most important operational physical parameters on the efficiency of the biosorbent: the initial concentration of the dye, the contact time between phases, the temperature, the dye solution pH, the biosorbent granule size, and the amount of biosorbent. The highest sorption capacity was obtained for the biosorbent obtained by microencapsulation, at pH 9, at biosorbent dose of 5.28 g/L and a contact time of about 100 min. The biosorption equilibrium was then studied by modeling the data on the Langmuir, Freundlich and Dubinin- Radushkevich isotherms. The Langmuir model is best suited for experimental data on both particle sizes leading to a maximum biosorption capacity of 188.679 mg/g at room temperature. The values of the adsorption energy, E, obtained with the help of the Dubinin-Radushkevich model-suggest that the type of mechanism (physical or chemical) involved in the biosorption process depends on the particle size of the biosorbent. The results confirm that the residual microbial biomass of Saccharomyces pastorianus immobilized in a polymeric matrix such as sodium alginate, can be considered an efficient biosorbent in retaining cationic organic dyes present in aqueous solutions in moderate concentrations.

Polysaccharides Used in Biosorbents Preparation for Organic Dyes Retaining from Aqueous Media.

Natural polymers can themselves be efficient as materials with biosorptive properties but can also be used to transform microbial biomass into an easy-to-handle form, respectively, into biosorbents, through immobilization. The article aims to study biosorbents based on residual microbial biomass (Saccharomyces pastorianus yeast, separated after the brewing process by centrifugation and dried at 80 °C) immobilized in sodium alginate. The biosorptive properties of this type of biosorbent (spherical particles 2 and 4 mm in diameter) were studied for removal of reactive dye Brilliant Red HE-3B (with concentration in range of 16.88-174.08 mg/L) from aqueous media. The paper aims at three aspects: (i) the physico-chemical characterization of the biosorbent (Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared (FTIR) spectra); (ii) the modeling of biosorption data in order to calculate the quantitative characteristic parameters using three equilibrium isotherms (Langmuir, Freundlich, and Dubinin-Radushkevich-DR); and (iii) the evaluation of thermal effect and the possible mechanism of action. The results of the study showed that biosorption capacity evaluated by Langmuir (I) model is 222.22 mg/g (ϕ = 2 mm) and 151.51 mg/g (ϕ = 4 mm) at 30 °C, and the free energy of biosorption (E) is in the range of 8.45-13.608 KJ/mol (from the DR equation). The values of thermodynamic parameters suggested an exothermic process due the negative value of free Gibbs energy (ΔG0 = -9.031 kJ/mol till -3.776 kJ/mol) and enthalpy (about ΔH0 = -87.795 KJ/mol). The obtained results underline our finding that the immobilization in sodium alginate of the residual microbial biomass of Saccharomyces pastorianus led to an efficient biosorbent useful in static operating system in the case of effluents with moderate concentrations of organic dyes.

Composites Based on Natural Polymers and Microbial Biomass for Biosorption of Brilliant Red HE-3B Reactive Dye from Aqueous Solutions.

Natural polymers have proven to be extremely interesting matrices for the immobilization of microbial biomasses, via various mechanisms, in order to bring them into a form easier to handle-the form of composites. This article aimed to study composites based on a residual microbial biomass immobilized in sodium alginate via an encapsulation technique as materials with adsorbent properties. Thus, this study focused on the residual biomass resulting from beer production (Saccharomyces pastorianus yeast, separated after the biosynthesis process by centrifugation and dried at 80 °C)-an important source of valuable compounds, used either as a raw material or for transformation into final products with added value. Thus, the biosorptive potential of this type of composite was tested-presenting in the form of spherical microcapsules 900 and 1500 µm in diameter-in a biosorption process applied to aqueous solutions containing the reactive dye Brilliant Red HE-3B (16.88-174.08 mg/L), studied in a batch system. The preparation and characterization of the obtained polymeric composites (pHPZC, SEM, EDS and FTIR spectra) and an analysis of different equilibrium isotherms (Langmuir, Freundlich and Dubinin-Radushkevich-D-R) were investigated in order to estimate the quantitative characteristic parameters of the biosorption process, its thermal effects, and its possible mechanisms of action. The modelling of the experimental data led to the conclusion that the studied biosorption process took place after reaching the Langmuir isotherm (LI), and that the main mechanism was possibly physical, being spontaneous and probably exothermic according to the values obtained for the free energy of biosorption (E = 8.45-13.608 kJ/mol, from the DR equation), as well as the negative values for the Gibbs free energy and the enthalpy of biosorption (ΔH0 = -87.795 kJ/mol). The results obtained lead to the conclusion that encapsulation of this residual microbial biomass in sodium alginate leads to an easier-to-handle form of biomass, thus being an efficient biosorbent for static or dynamic operating systems for effluents containing moderate concentrations of reactive organic dyes.