Molar Ratio Of Components Research Articles

Влияние катионов Fe(II) и Fe(III) на коррозию низкоуглеродистой стали в смеси соляной и фосфорной кислот, содержащей композиционные ингибиторы на основе ИФХАН-92

Corrosion of 08PS low-carbon steel has been studied in a wide temperature range t = 25—100 °C in 1 M HCl + 1 M H3PO4, 2 M HCl and 2 M H3PO4 solutions inhibited by a binary mixture IFKhAN-92 + KNCS (molar ratio of components 9:1) and a three-component mixture IFKhAN-92 + KNCS + urotropine (9:1:400) in the presence of high concentrations of Fe(III) and Fe(II) salts, as well as in their joint presence. It is shown that under experimental conditions the three-component inhibitor mixture provide protection of steel in 1 M HCl + 1 M H3PO4 even in the presence of Fe(III), Fe(II) salts or their mixtures. Under similar conditions in individual 2 M HCl the protective effects of inhibitors are lower. A stronger deceleration of steel corrosion by composite inhibitors based on IFKhAN-92 in HCl + H3PO4 solutions containing Fe(III) salts, in comparison with similar solutions of individual HCl, is largely due to the binding of Fe(III) cations by phosphate anions into complexes, which considerably reduces their chemical activity and, as a consequence, the steel corrosion rate.

Assessment of the influence of the mineral complex of rutin on the degree of expression of anti-diabetic activity

Assessment of the influence of the mineral complex of rutin on the degree of expression of anti-diabetic activity

Glass formation mechanism in aqueous formic acid solutions

The glass-formation mechanism in the HCOOH–H2O system, which occurred at component molar ratios from 1:2 to 3:2, was studied by calorimetry and quantum chemistry. The results were analyzed and interpreted in light of the laws that guide the formation of stable H-bonded hetero associates in binary systems. The thermo analytical curves for 1:2, 1:1, and 3:2 glasses each showed three thermal events due to glass transition at about –130°С, crystallization, and melting of crystals. The structures and energy parameters were calculated in terms of density functional theory for polymeric chain moieties comprised of one or two types of the HCOOH⋅(H2O)2, (HCOOH)2⋅(H2O)2, and (HCOOH)3⋅(H2O)2 hetero associates. Glass formation was shown to occur precisely when [HCOOH]:[H2O] = 1:2–3:2 due to the ability of those hetero associates to be linked into strongly bonded, unlimitedly long polymeric chains. The energy parameters of 1:2, 1:1, and 3:2 samples derived from the calorimetric experiment were compared to those gained from the calculations of moieties that model polymeric structures in these samples, so all experimentally observed thermal events were interpreted at the molecular level. The glass-formation mechanism in the HCOOH–H2O system where the key role is played by hetero associates and not by individual molecules was elucidated.

Совместное влияние катионов Fe(II) и Fe(III) на коррозию низкоуглеродистой стали в смеси серной и фосфорной кислот, содержащих композиционные ингибиторы на основе ИФХАН-92

Corrosion of 08PS low-carbon steel was studied in a wide temperature range t = 25—100 °C in 1 M H2SO4 + 1 M H3PO4, 2 M H2SO4 и 2 M H3PO4, inhibited by the binary mixture IFKhAN-92 + KNCS (a molar ratio of components 9:1) and a three-component mixture IFKhAN-92 + KNCS + urotropine (9:1:400), in the presence of high concentrations of Fe(III) and Fe(II) salts, as well as in their joint presence. It is shown that under experimental conditions the corrosion inhibitors under study provide effective protection of steel in 1 M H2SO4 + 1 M H3PO4 even in the presence of Fe(III), Fe(II) salts or their mixtures. The highest protective effects are provided by a three-component inhibitor mixture. Under similar conditions in individual 2 M H3PO4 and, especially, 2 M H2SO4, the protective effects of inhibitors are lower. A stronger deceleration of steel corrosion by composite inhibitors based on IFKhAN-92 in H2SO4 + H3PO4 solutions containing Fe(III) salts in comparison with similar solutions of individual H2SO4, is largely due to the binding of Fe(III) cations by phosphate anions into complexes, that significantly reduces their chemical activity and, as a result the corrosion rate of steel.

SYNTHESIS AND APPLICATION OF MIXED ETHYLENE GLYCOL DIESTERS BASED ON PETROLEUM ACIDS CHEMISTRY AND CHEMICAL TECHNOLOGY

In order to increase the range of plasticizers and antioxidants using the ZnO catalyst, mixed ethylene glycol diesters based on petroleum and fatty acids were synthesized by a waste-free method. To determine the optimal conditions for obtaining the target products, the effect of temperature, the amount of catalyst, the molar ratio of the components involved in the reaction for the maximum yield were studied and the optimal condition was established with a yield of 90-93. The properties of mixed diesters of petroleum acids have been studied, the physicochemical parameters have been determined by analytical and spectral methods. The degree of compatibility of ethers with polyvinyl chloride and the ability to prolong the life of diesel fuel have been determined. It was found that ethers can be recommended as effective plasticizers for polyvinyl chloride and antioxidants for diesel fuel. Taking into account the wide practical application of mixed esters, including esters of petroleum acids, and their high demand, the main goal of the article is to obtain mixed ethylene glycol esters based on natural, synthetic and fatty acids with a high yield without waste method, as well as to study their properties and applications. In this article, to solve the problem posed, natural petroleum acids of the fraction 90-230ºC / 6.65 × 10-4 MPa were used in the studies, taken from the "Meriken" unit of the H. Aliyev`s New Baku Oil Refinery, as well as synthetic petroleum acids synthesized by liquid-phase oxidation with atmospheric oxygen at a temperature of 135-140°С. In the following studies, asymmetric ethylene glycol diesters were synthesized based on natural, synthetic and fatty acids of the C6-C8 series at temperatures of 80-140oC, with a catalyst amount of 0.6-1.6% by weight (with respect to acid), molar ratio of components 2:1.1-1.6, the optimal conditions were determined (T,°C = 110-120, acid: alcohol - 2:1.3-1.5 mol, ZnO - 0.8-1.5% by weight ( in relation to acid)), the properties of the synthesized mixed diesters have been studied, their indicators have been determined by modern analytical and spectral methods, and the material balance of these ethers has been compiled. Other representatives of ethylene glycol based on oil and fatty acids in a similar way were synthesized and the physicochemical parameters were determined. The synthesized products are light yellow, transparent, odorless, insoluble in water, readily soluble in organic solvents. The compatibility of mixed diesters with polyvinyl chloride (PVC), as well as the effect of diesel fuel on thermal-oxidative stability in laboratory conditions has been studied. The research results are presented below: • mixed diesters of petroleum acids have been synthesized in the presence of a ZnO catalyst by one-stage method, which makes it possible to reduce intermedi; • the influence of various amounts of catalyst, the molar ratio of the components involved in the reaction, the temperature range the course of the reaction in order to select the optimal synthesis conditions were studied, mixed esters in high yield were synthesized and their physicochemical parameters by analytical and spectral methods were determined; • the degree of compatibility of mixed diesters synthesized on the basis of petroleum and fatty acids with PVC has been studied and tested as a new component to improve the thermal stability of diesel fuel. These esters can be recommended as effective plasticizers and antioxidants. Keywords: natural petroleum acids, synthetic petroleum acids, ethylene glycol, mixed diester, plasticizer, antioxidant

Hydrothermally Assisted Fabrication of TiO2-Fe3O4 Composite Materials and Their Antibacterial Activity.

The TiO2-Fe3O4 composite materials were fabricated via the hydrothermal-assisted technique. It was determined how the molar ratio of TiO2 to Fe3O4 influences the crystalline structure and morphology of the synthesized composite materials. The effect of the molar ratio of components on the antibacterial activity was also analyzed. On the basis of XRD patterns for the obtained titanium(IV) oxide-iron(II, III) oxide composites, the two separate crystalline forms—anatase and magnetite —were observed. Transmission electron microscopy revealed particles of cubic and tetragonal shape for TiO2 and spherical for Fe3O4. The results of low-temperature nitrogen sorption analysis indicated that an increase in the iron(II, III) oxide content leads to a decrease in the BET surface area. Moreover, the superparamagnetic properties of titanium(IV) oxide-iron(II, III) oxide composites should be noted. An important aim of the work was to determine the antibacterial activity of selected TiO2-Fe3O4 materials. For this purpose, two representative strains of bacteria, the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, were used. The titanium(IV) oxide-iron(II, III) oxide composites demonstrated a large zone of growth inhibition for both Gram-positive and Gram-negative bacteria. Moreover, it was found that the analyzed materials can be reused as antibacterial agents in three consecutive cycles with good results.

Development of a lyophilized liposomal dosage form indolocarbazole derivative — LHS-1208

Aim. The aim of this work was to create a lyophilized liposomal dosage form of native hydrophobic antitumor compound from the group of indolocarbazole derivatives — LHS-1208. Materials and methods. Quantitative determination of the drug content was carried out on a Cary 100 spectrophotometer using a standard sample at λ = 320 ± 2 nm. The analysis of the average diameter of liposomes was carried out by the method of correlation spectroscopy of light scattering using devices Nicomp-380 nanosizer and Zetasizer Nano ZS zetasizer, using the latter, the zeta potential of the liposomal dispersion was also measured. To measure the pH of the solution, a HANNA pH 211 pH meter was used. The dynamic viscosity was measured on a Vibro Viscometer SV-10 viscometer. Lyophilization was carried out in an Edwards Minifast DO.2 freeze-drying chamber. Results. Experimental models of compositions of lyophilized liposomal dosage form LHS-1208 with various molar ratios of components were obtained and analyzed. TLC analysis using several solvent systems can be used to detect and identify LHS-1208 in a liposomal dosage form. According to the results of the study, a spectrophotometric method was developed for the quantitative determination of the LHS-1208 content in the composition of a liposomal dosage form. Based on the studies carried out, quality indicators were selected for standardization of lyophilized liposomal dosage form LHS-1208 and subsequent development of the draft regulatory documentation. Conclusion. As a result of the complex pharmaceutical research, the optimum composition of the components was determined, and the technology for production of liposomal dosage form LHS-1208 was developed.

Chemical characterization of the soluble polysaccharides of the red alga Acanthophora spicifera from La Paz Bay, Baja California Sur, México

Acanthophora spicifera is an invasive red alga that was recently detected in La Paz Bay, Baja California Sur, Mexico, where it has developed into a large biomass. Because it is a new species in the region, the characteristics and properties of the soluble polysaccharides (SPs) that it contains are unknown. To determine the content, chemical composition, and properties of SPs in A. spicifera, monthly samplings were carried out in 2013 at Point Roca Caimancito in La Paz Bay, and native and alkali-treated polysaccharides were extracted and characterized. The alkaline treatment produced lower yields and modified the composition of A. spicifera SPs. The polysaccharides obtained before or after the alkaline treatment had low viscosity and did not have gelling properties. In line with the obtained results, the molar ratio of components (galactose, 3,6-anhydrogalactose, sulfates [Gal:3,6-AG:sulfates]) for native (1.00:0.30:0.23) and alkali-treated (1.00:0.30:0.17) polysaccharides showed that A. spicifera SPs have a lower proportion of sulfates than that in polysaccharides belonging to carrageenans but greater than that in polysaccharides belonging to true agar. The Fourier-transform infrared spectra of SPs showed characteristic signals for sulfated galactans, with the presence of pyruvic acid; after the alkaline treatment, characteristic signals for agar-type polysaccharides (agaroid) were observed. Although A. spicifera polysaccharides have no gelling properties, additional studies are needed to clarify the structure of the SPs it contains to find appropriate uses for this resource.

Development of a Liposomal Dosage Form Based on Hydrophobic Derivative of Indolocarbazole

Introduction . An original N-glycoside derivative of indolocarbazole LHS-1269 with a carbohydrate xylose residue was synthesized at the N.N. Blokhin Russian Cancer Research Center Ministry of Health of Russia. It is characterized by high antitumor activity against a number of transferable ascitic and solid tumors in vivo experiments. Due to the hydrophobic properties of the substance LHS-1269, a method of solubilization by encapsulation in phospholipid vesicles - liposomes is proposed for creating an injectable dosage form. Aim . Development of the composition of a model of a liposomal dosage form for injection of an indolocarbazole derivative LHS-1269. Materials and methods . Substance LHS-1269 (N.N. Blokhin Russian Cancer Research Center Ministry of Health of Russia), egg phosphatidylcholine (PC, E PC S, Lipoid, Germany), cholesterol >99 % (Sigma-Aldrich, Japan), polyethylene glycol-2000-distearoylphosphatidylethanolamine (PEG-PE, Lipoid, Germany). To prepare phospholipid vesicles, the method of lipid film hydration with subsequent filtration and extrusion was used. The obtained liposomes were analyzed using the method of spectrophotometry, laser scattering spectroscopy, the method of determining the electrophoretic mobility of particles, and viscometry. Results and discussion . On the basis of lipid components and active substance in various molar ratios, compositions were made and experimental models of liposomal dispersion were obtained. The compositions were evaluated based on the effectiveness of LHS-1269 incorporation into liposomes and physical and chemical parameters - dispersion viscosity, vesicle size distribution, and zeta-potential. As a result of the analysis of 7 studied compositions, the optimal molar ratios of the drug form components - LHS-1269/PC 1:160 and PC/cholesterol/PEG-PE 1:0.33:0.003 were determined. The use of this composition allows us to obtain relatively stable (zeta-potential -33 mV) homogeneous liposomes with a diameter of 190 nm with a maximum level of encapsulation of the active substance of 98 %. Conclusions . As a result of technological and chemical-pharmaceutical research, the composition of a model of a liposomal dosage form for injection of the indolocarbazole derivative LHS-1269 has been developed.

Effect of polyelectrolyte complex formation on the antibacterial activity of copolymer of alkylated 4-vinylpyridine.

Polymers bearing quaternized 4-vinylpyridine (QVP) groups are known for their antibacterial activities and these polymers can form polyelectrolyte complexes (PEC) with polyanions through electrostatic interactions. PEC formation can be used to adjust the antibacterial activity of polymers of QVP, deliver active molecules, or design antibacterial supramolecular structures. However, the antibacterial activity of PECs of QVP polymers has not been investigated. In this study, a copolymer of QVP was mixed with polyacrylic acid in various molar ratios of components to form PECs. Hydrodynamic diameters and zeta potentials of formed PECs were determined by dynamic and electrophoretic light scattering spectroscopy techniques. The zeta potentials of PECs changed between –24 and +16 mV with variation in the ratio of components. Antibacterial assays against E. coli revealed a relation of PEC formation with antibacterial activity since MIC values changed between 125–1000 μg/mL according to the ratio of components.

Microwave-assisted synthesis of a TiO2-CuO heterojunction with enhanced photocatalytic activity against tetracycline

A microwave method was used for the synthesis of TiO2-CuO oxide systems. A detailed investigation was made of the effect of the molar ratio of components (TiO2:CuO = 9:1, 7:3, 5:5, 3:7, 1:9) on the crystalline structure and morphology. Transmission electron microscopy (TEM) confirmed the presence of octahedral and rod-shaped titania particles and sheet copper(II) oxide particles; moreover, HRTEM analysis indicated the presence of a heterojunction between TiO2 and CuO. The synthesized materials were analyzed by X-ray diffraction (XRD) and Raman spectroscopy, and two crystalline forms (anatase and monoclinic CuO) were detected. The key element of the work was to determine the photocatalytic activity of the obtained binary oxide systems in the degradation of tetracycline. Photo-oxidation tests proved that the binary oxide materials (especially the (9)TiO2-(1)CuO and (7)TiO2-(3)CuO samples) demonstrate high photocatalytic activity in the decomposition of tetracycline (95% after 90 min irradiation) compared with the reference titania samples. Furthermore, a Z-scheme heterojunction photocatalytic process mechanism was proposed. Another important part of the work was the determination of tetracycline photodegradation products using the HPLC/MS technique.

Drug-in-hydroxypropyl-β-cyclodextrin-in-lipoid S100/cholesterol liposomes: Effect of the characteristics of essential oil components on their encapsulation and release.

Drug-in-cyclodextrin-in-liposome (DCL) represents a very promising approach for preserving essential oil (EO) components, thereby extending their shelf life and activity. In this study, we examined the effect of chemical structure, octanol/water partition coefficient (log P), and Henry's law constant (Hc) on the encapsulation and the release of monoterpenes (eucalyptol, pulegone, terpineol, and thymol) and phenylpropenes (estragole and isoeugenol) from DCLs. Hydroxypropyl-β-cyclodextrin/EO component (HP-β-CD/EO component) inclusion complexes were prepared in aqueous solution and loaded into liposomes by the ethanol injection method. The phospholipid:cholesterol:EO component molar ratio determined for DCL structures was affected by characteristics of EO components. The presence of a propenyl tail or a hydroxyl group in the structure of EO component may improve its loading into DCLs. Furthermore, low encapsulation efficiency (EE) was obtained for DCLs exhibiting high cholesterol membrane content. In addition, a positive linear relationship was found between the loading ratio of monoterpenes into DCLs and their hydrophobic character expressed as log P. The release of components from DCLs was influenced by their EE into the formulations. Finally, DCL formulations retain considerable amounts of EO components after 10months.

The performance of multicomponent oxide systems based on TiO2, ZrO2 and SiO2 in the photocatalytic degradation of Rhodamine B: Mechanism and kinetic studies

Novel binary and ternary oxide photocatalysts based on titania, zirconia and silica were synthesized via a sol-gel method assisted by a calcination process. The effect of the molar ratio of components as well as the temperature of calcination on the physicochemical and photocatalytic properties of the final products was examined. Particle size distribution (NIBS), scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), Raman spectroscopy, low-temperature N2 sorption, and X-ray fluorescence (XRF) were employed to investigate the dispersion, morphology, crystalline and textural structure as well as the chemical composition of the photocatalysts. Additionally, X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were used to confirm the chemical surface concentration and the presence of characteristic surface groups of the synthesized materials. The key stage of the research involved evaluation of the photocatalytic behavior of the synthesized materials in the catalytic decomposition of Rhodamine B (RhB) dye. The photocatalytic studies focused on determination of the effect of the type and crystalline structure of the photocatalyst, the pH of the reaction system, and the irradiation time on the efficiency of degradation of RhB in the presence of the synthesized oxide materials.

The creation of immunofluorescence probes based on monoclonal antibodies series ICO and phycoerythrin - fluorophore of phycobiliprotein group for analysis of cell populations by flow cytometry

Introduction . Fluorescent probes based on monoclonal antibodies (MAb) are widely used in scientific and clinical research in the field of oncology, hematology, immunology, epidemiology. The unique spectral properties of the natural protein, phycoerythrin (PE), made it the dominant dye widely used for the preparation of fluorescent probes based on MAb. Objective . To create of fluorescent probes based on the MAb and the fluorescent dye PE by two alternative methods of protein synthesis. Materials and methods . MAb to T lymphocyte antigen (clone ICO-86, clone ICO-31), fluorescent dye PE and bifunctional agents SPDP and SMCC were used in the work. Liquid chromatography methods were used for isolation and purification of MAb: in the first step, affinity isolation of immunoglobulins on the immobilized protein G or anion exchange column chromatography. Gelfiltration on a PD-10 column was used to purify the conjugates (immunofluorescent probes, IFP) in the second step, the concentration and labeling density of the IFP were determined spectrophotometrically. Results . Conjugation of MAb with PE was carried out at a molar ratio of components of 1: 2. For this both components of the conjugation reaction (PE and MAb) were separately modified. For the creation of IFP on the basis of the MAb of the ICO series, both methods of conjugation of Mab with PE are applicable, but method II, in which the chemical modification by the bifunctional SMCC agent is exposed only to the PE molecule by its free amino groups, and the immunoglobulin molecule is conserved in the maximally native state is preferred. Conclusion . The methods described in the article allow to obtain immunofluorescent probes based on antibodies of the ICO series that are comparable in their analytical characteristics to foreign commercial analogs.

Hydrothermal-assisted synthesis of highly crystalline titania-copper oxide binary systems with enhanced antibacterial properties.

Binary oxide systems containing TiO2 and CuO were synthesized using hydrothermal treatment and shown to have enhanced antibacterial properties. A detailed investigation was made of the effect of the molar ratio of components (TiO2:CuO = 7:3, 5:5, 3:7, 1:9) on the physicochemical parameters and antibacterial activity. Analysis of morphology (SEM, TEM and HRTEM) confirmed the presence of spherical and sheet-shaped particles. On the XRD patterns for the binary oxide materials, two crystalline forms (anatase and monoclinic CuO) were observed. It was found that an increase in CuO content led to a decrease in the BET surface area of the TiO2-CuO binary oxide systems. The synthesized TiO2-CuO materials exhibited very good antibacterial activity against both Gram-positive (methicillin-resistant Staphylococcus aureus and Bacillus cereus) and Gram-negative (Salmonella Enteritidis and Pseudomonas aeruginosa) bacteria. The obtained results show that TiO2-CuO oxide materials may have applications in the biomedical and food industries.

Synthesis of ordered lamellar supermicroporous silica with rigid neutral and long-chain cationic composite templating route.

Using a mixture of neutral primary amine dehydroabietylamine (DHAA) and long-chain cetyltrimethyl ammonium bromide (CTAB) as the template, ordered lamellar supermicroporous silicas were synthesized with NaOH as the base source and tetraethylorthosilicate (TEOS) as the silica source. The concentrations of DHAA, CTAB, and NaOH in the synthesis system had great effects on the structural properties of the samples. When the molar ratio of components was nTEOS:nCTAB:nDHAA:nNaOH:nH2O = 1:0.114:0.00457:0.5:60, the material showed a lamellar phase with the highest ordering degree. By adding only a trace amount of DHAA into the synthesis system, the structure of the samples could be transformed from cubic phase to lamellar phase, since the added DHAA solubilized in CTAB micelles to change the effective surfactant ion pair packing parameter. The dosage of CTAB should be moderate; too high or too low will decay the ordering degree of the lamellar structure.A much higher concentration of NaOH resulted in an ethanol-rich solvent in which the DHAA did not solubilize in the micelles of CTAB, but adsorbed at the hydrophilic headgroup–solvent interface. Accordingly, a structural transformation from lamellar phase to hexagonal phase occurred.

Novel hybrid liposomal formulations based on imidazolium-containing amphiphiles for drug encapsulation.

Novel liposomes based on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and imidazolium-containing amphiphiles with various length of hydrophobic tail at various molar ratio of components have been fabricated. Obtained formulations were characterized using dynamic and electrophoretic light scattering as well as transmission electron microscopy techniques. It has been established, that DPPC liposomes modification by these cationic amphiphiles resulted in zeta potential increase from +3 mV to +45-70 mV and improve its stability for a long time (more than 6 months, whereas unmodified liposomes have been destructed after 2 weeks of storage). Hydrodynamic diameter of prepared hybrid liposomes was in the range of 70-100 nm depending on its composition. Fabricated hybrid carriers have been used for drug (metronidazole) encapsulation. It has been shown, that superior encapsulation characteristics (encapsulation efficiency was 75%) exhibited hybrid liposomes composed from octadecyl derivative. Increase of the time of total release of encapsulated drug from hybrid liposomes in comparison with unencapsulated drug by 1.7 times has been demonstrated.

PEO-b-PCL grafted niosomes: The cooperativilty of amphiphilic components and their properties in vitro and in vivo.

Niosomes belong to drug delivery systems and consist mainly of non-ionic surfactants and cholesterol. In this study, we designed and developed systems composed of non-ionic surfactants i.e. Tween 80, Span 80 and cholesterol with and without poly(ethylene oxide)-b-poly(ε-caprolactone) (PEO-b-PCL) block copolymer, using different molar ratios of the above components. The nanosystems were formed by the thin-film hydration method with purified water as dispersion medium. Several physicochemical techniques were utilized in order to study the physicochemical and morphological characteristics of the prepared assemblies. The results showed that the presence of the block copolymer alters significantly the size and morphology of neat surfactant/cholesterol niosomes. The ageing studies also revealed that the stability is strongly dependent on the nature and the molar ratios of the components. Moreover, neither of the studied nanosystems exhibited elevated signs of cellular toxicity in vitro nor acute systemic toxicity in vivo short-term experiments. This investigation covers a new field of drug delivery platforms those of niosomes composed by different biomaterials i.e. surfactants and block copolymers.

Novel Ag-ZnO-La2O2CO3 photocatalysts derived from the Layered Double Hydroxide structure with excellent photocatalytic performance for the degradation of pharmaceutical compounds

Abstract In this work, we have prepared the Ag-ZnO-La2O2CO3 nanomaterials as promising photocatalysts for the photocatalytic degradation of pharmaceutical pollutants. Firstly, a series of ZnAl1-xLax(CO3) (0 ≤ x ≤ 0.5) layered double hydroxides (LDHs) were synthesized by the co-precipitation method at the component molar ratio of Zn/(Al + La = 3, where La/Al = 0, 0.25 and 0.5). Photocatalysts were prepared by the calcination of the LDH precursors at different temperatures of 300, 400, 500, 600, 800 and 1000 °C. The effects of the La/Al molar ratio and the calcination temperature on the photocatalytic activity of the catalysts were evaluated by the degradation of caffeine as a model pharmaceutical pollutant in aqueous solutions under the UV irradiation. Thereafter, in order to increase the photocatalytic activity, the catalysts obtained at the optimal La/Al molar ratio and calcination temperature were doped with the Ag noble metal at various concentrations (i.e. 1, 3 and 5 wt%) using the ceramic preparation process to obtain the desired Ag-ZnO-La2O2CO3 catalysts. The synthesized photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX) and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS). Detailed photocatalytic experiments based on the effects of the irradiation time, the dopant amount, the catalyst dose, the initial solution pH and reuseability were performed and discussed in this study. The Ag doped material showed significantly a higher photocatalytic activity compared to the undoped, pure ZnO and P-25 catalysts. The experimental results show that the highest photocatalytic activity was obtained from the Ag (5%) doped Zn-0.75Al-0.25La-CO3 photocatalysts calcined at 500 °C with a degradation efficiency of 99,4% after 40 min of irradiation only. This study could provide a new route for the fabrication of high performance photocatalysts and facilitate their application in the environmental remediation issues.

Phase Diagram of a Stratum Corneum Lipid Mixture.

Computational modeling of lipid ternary mixtures is challenging because of their complicated and segmented phase diagram, the long timescales required for mixing the system components, and the necessity to sufficiently sample the three-dimensional phase space. Here, we investigate a ternary system, which mimics the lipid matrix of the stratum corneum, the outermost layer of the epidermis and the primary barrier for transdermal drug absorption. Our system consists of ceramide, cholesterol, and lignoceric acid at 23 different composition ratios, which we study at two different temperatures using coarse-grained molecular dynamics (CG MD) simulations. As CG MD simulations heavily depend on the choice of parameters, first an improved set of ceramide CG parameters was developed that reproduces experimental and all-atom simulation data. Second, the performance of the recently updated MARTINI 2015 cholesterol force field was systematically evaluated and compared to the 2007 model. We provide a detailed analysis of the structural and dynamic properties of the ternary system, such as area per lipid, area compressibility modulus, lipid order parameters, bilayer thickness, lipid tail interdigitation, and lateral self-diffusion. Based on the analysis of these properties, we devise a phase diagram of the ternary system, where three different phases, namely, liquid-disordered, gel, and liquid-ordered, are observed. The individual occurrence of a certain phase not only depends on the component molar ratio and the temperature but also decisively on the employed cholesterol force field.