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Many regions of the United States contain manganese deposits economically valuable in New England, Appalachian, and Piedmont regions in the Eastern United States, in Northern Arkansas, and, to a small extent, in Central–Western California. Mn oxide/hydroxide (commonly referred to as Mn oxide minerals) are found in a wide variety of geological settings and occur as fine-grained aggregates, veins, marine and freshwater nodules and concretions, crusts, dendrites, and coatings on rock surfaces (e.g., desert varnish). How manganese oxides form and what mechanisms determine which oxides are likely to form are limited and still debated. This paper focuses on Mn oxides collected at the southern bound of the abandoned open-pit site called Crimora Mine (Augusta County, Virginia). This study uses mineralogical and chemical features to shed light on the origin of manganese deposits in Crimora along the western foot of the Blue Ridge in South–West Virginia. We report the first detailed study on the genesis of the Crimora manganese deposit conducted since the mine was closed in the 1950s. Crimora Mine sample is dark black fine- to medium-grained round and oblong nodules coated with a fine-grained intermix of yellowish earthy limonite, clays, and quartz. Scanning electron microscopy (SEM) revealed that the Crimora Mn-oxides exhibit concentric layering, breccia-like matrices, and veins. X-ray powder diffraction (XRPD) identified the set of Mn minerals as hollandite and birnessite. The concentration and range of dissolved chemical species in freshwater, seawater, and hydrothermal depositional fluids impart a geochemical signature to the Mn-oxides, providing a diagnostic tool to shed light on their genetic origin. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the Crimora manganese oxides shows Mn, Fe, and Ti, as well as trace elements such as Co, Ba, Y, Zn, Cr, Ni, Tl, La, V, and Li. A bivariate analysis based on the geochemical correlation of Mn and other common substituting cations (e.g., Fe, Co, Ti) shows a mixed genesis in different environments with varying biological and sedimentary supergene (freshwater and marine) conditions. These data suggest that the Mn-rich deposit in Crimora, VA, was formed in a continental margin environment of surficial deposits and reprecipitated in mixed biogenic and supergene conditions. [ABSTRACT FROM AUTHOR]

The overall need for the preparation of new medicinal radionuclides has led to the fast development of new sorption materials, extraction agents, and separation methods. Inorganic ion exchangers, mainly hydrous oxides, are the most widely used materials for the separation of medicinal radionuclides. One of the materials that has been studied for a long time is cerium dioxide, a competitive sorption material for the broadly used titanium dioxide. In this study, cerium dioxide was prepared through calcination of ceric nitrate and fully characterized using X-ray powder diffraction (XRPD), infrared spectrometry (FT-IR), scanning and transmission electron microscopy (SEM and TEM), thermogravimetric and differential thermal analysis (TG and DTA), dynamic light scattering (DLS), and analysis of surface area. In order to estimate the sorption mechanism and capacity of the prepared material, characterization of surface functional groups was carried out using acid-base titration and mathematical modeling. Subsequently, the sorption capacity of the prepared material for germanium was measured. It can be stated that the prepared material is prone to exchange anionic species in a wider range of pH than titanium dioxide. This characteristic makes the material superior as a matrix in 68Ge/68Ga radionuclide generators, and its suitability should be further studied in batch, kinetic, and column experiments. [ABSTRACT FROM AUTHOR]

Many regions of the United States contain manganese deposits economically valuable in New England, Appalachian, and Piedmont regions in the Eastern United States, in Northern Arkansas, and, to a small extent, in Central–Western California. Mn oxide/hydroxide (commonly referred to as Mn oxide minerals) are found in a wide variety of geological settings and occur as fine-grained aggregates, veins, marine and freshwater nodules and concretions, crusts, dendrites, and coatings on rock surfaces (e.g., desert varnish). How manganese oxides form and what mechanisms determine which oxides are likely to form are limited and still debated. This paper focuses on Mn oxides collected at the southern bound of the abandoned open-pit site called Crimora Mine (Augusta County, Virginia). This study uses mineralogical and chemical features to shed light on the origin of manganese deposits in Crimora along the western foot of the Blue Ridge in South–West Virginia. We report the first detailed study on the genesis of the Crimora manganese deposit conducted since the mine was closed in the 1950s. Crimora Mine sample is dark black fine- to medium-grained round and oblong nodules coated with a fine-grained intermix of yellowish earthy limonite, clays, and quartz. Scanning electron microscopy (SEM) revealed that the Crimora Mn-oxides exhibit concentric layering, breccia-like matrices, and veins. X-ray powder diffraction (XRPD) identified the set of Mn minerals as hollandite and birnessite. The concentration and range of dissolved chemical species in freshwater, seawater, and hydrothermal depositional fluids impart a geochemical signature to the Mn-oxides, providing a diagnostic tool to shed light on their genetic origin. Inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis of the Crimora manganese oxides shows Mn, Fe, and Ti, as well as trace elements such as Co, Ba, Y, Zn, Cr, Ni, Tl, La, V, and Li. A bivariate analysis based on the geochemical correlation of Mn and other common substituting cations (e.g., Fe, Co, Ti) shows a mixed genesis in different environments with varying biological and sedimentary supergene (freshwater and marine) conditions. These data suggest that the Mn-rich deposit in Crimora, VA, was formed in a continental margin environment of surficial deposits and reprecipitated in mixed biogenic and supergene conditions.

Solvent-free preparation types for cyclodextrin complexation, such as co-grinding, are technologies desired by the industry. However, in-depth analytical evaluation of the process and detailed characterization of intermediate states of the complexes are still lacking in areas. In our work, we aimed to apply the co-grinding technology and characterize the process. Fenofibrate was used as a model drug and dimethyl-β-cyclodextrin as a complexation excipient. The physical mixture of the two substances was ground for 60 min; meanwhile, samples were taken. A solvent product of the same composition was also prepared. The intermediate samples and the final products were characterized with instrumental analytical tools. The XRPD measurements showed a decrease in the crystallinity of the drug and the DSC results showed the appearance of a new crystal form. Correlation analysis of FTIR spectra suggests a three-step complexation process. In vitro dissolution studies were performed to compare the dissolution properties of the pure drug to the products. Using a solvent-free production method, we succeeded in producing a two-component system with superior solubility properties compared to both the active ingredient and the product prepared by the solvent method. The intermolecular description of complexation was achieved with a detailed analysis of FTIR spectra. [ABSTRACT FROM AUTHOR]

Doxycycline hyclate is Biopharmaceutical Classification System, class I drug (high solubility and high permeability), but it is associated with poor photostability. It is in the class of tetracycline antibiotic, which is used to treat various infections, but its bioavailability is compromised due to its sensitivity to light and aqueous instability. In this paper, the influence of inclusion complexation with different cyclodextrins, i.e., αCD, γCD, HPβCD and RMβCD, on the photostability of doxycycline hyclate in aqueous media was investigated. Host–guest inclusion complexes were prepared by freeze- drying method. The prepared complexes were characterized for drug content, SEM, XRPD, in vitro permeation studies and photostability studies. XRPD showed diffused peaks for most of the complexes, while SEM showed irregularly shaped particles. The formulation D20 (Drug: γCD in 1:20 molar ratio) showed the highest % drug content (83.72 ± 1.2%), and the formulations D1 (Drug: αCD in 1: 2 molar ratio) showed the lowest % drug content among all the CD complexes. It was found that the photodegradation of the drug was reduced significantly upon complexation. For Drug: CD complexes, the photostability of the aqueous solution of drug/CD complexes was found to be in the order of γCD > RMβCD > HPβCD > αCD with maximum photostability shown by Drug: γCD (1:20 molar ratio) complex. The obtained results suggested that cyclodextrin complexation can be used as an alternative approach for increasing the photostability of doxycycline hyclate. [ABSTRACT FROM AUTHOR]

Data revealing the phase and chemical compositions of natural black sands from “El Ostional” beach, located in the northern Ecuadorian Pacific coast have been presented. The samples were collected from six points over the shore area of approximately 500 × 40 m2. The data on crystalline phases (iron titanium oxide, orthoclase feldspar and zircon) were determined by X-ray powder diffraction (XRPD), while semi-quantitative chemical analyses of major (Fe and Ti) and trace elements were obtained by X-ray fluorescence spectroscopy (XRF). The phase composition was verified by scanning electron microscopy (SEM), using backscattered electron (BSE) mode and energy dispersive spectroscopy (EDS). These comprehensive data are a contribution to valorize ilmenite-hematite solid solutions from natural resources towards the identification of novel technological applications.

This study is focused on the Phoenician Red Slip Ware , a cultural and chronological marker, unearthed in the archaeological site of Motya. The vessels are dated back from the 8th to early 5th century B.C. The ceramics were investigated using Optical Microscopy (OM), X-ray Powder Diffraction (XRPD), Scanning Electron Microscopy (SEM) and Electron Microprobe Analysis (EMPA). The results on mineralogical assemblage, microstructure and chemical composition of the ceramic body suggest a careful selection of the raw materials (i.e., clay and tempers) and firing temperature in the range > 750 and <850 °C, under oxidizing conditions. The Red Slip decoration consists of clay-rich coating, enriched in Fe. The comparison of the mineralogical and chemical composition of local clay deposits with that of the ceramic production allowed distinguishing local from imported vessels. [ABSTRACT FROM AUTHOR]

The aim of the present research work was to explore the impact of ibuprofen-captisol® (sulfobutylether sodium salt of β-CD) inclusion complexes on in vitro dissolution performance. Phase solubility studies of ibuprofen using the carrier captisol® had generated A L -type profiles which indicated the formation of 1:1 stoichiometric inclusion complexes. The study revealed that more stable complexes of ibuprofen-captisol® were formed in double distilled water compared to phosphate buffer (pH 7.2) as more fraction of the drug is in un-ionized form. Ibuprofen-captisol® complexes were prepared by (i) kneading and (ii) freeze-drying technique with the various drug-carrier ratio (1:1, 1:3 and 1:5 w/w). Complex formation was explained on the basis of physical mixtures (PMs) of identical compositions. Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), Scanning electron microscope (SEM) and Molecular docking studies were carried out to establish the inclusion complexation. Molecular docking confirmed the possibility of forming a complex between drug and polymer, and it was evident from the energy-minimized structure of the drug-polymer complex. Minimization of energy suggested the formation of a stable drug-polymer complex with binding energy of (−) 3.6 kcal mol −1 . The negative docking energy of the complex formation justifies the reason of its solubility enhancement. The complexes prepared by freeze-drying technique were found to be superior in the enhancement of in vitro dissolution rate of ibuprofen when compared to that of complexes prepared by kneading technique. [ABSTRACT FROM AUTHOR]

Non-structural lime-based injection grouts with reduced water content were designed for the stabilisation of delaminated plasters in water-sensitive contexts. Two water reducing components were considered: (i) ethanol, as a partial substitute for water, being a less effective solvent for ionic substances, (ii) ovalbumin, a protein found in egg white (it is a water-reducer and air-entrainer). The influence of ethanol and ovalbumin on grouts was assessed in terms of its effect on chemical reactions and formation of phases, the internal structure of the set binders and porosity, through a combination of X-ray powder diffraction coupled with quantitative phase analysis by means of the Rietveld method, scanning electron microscopy with EDS microanalysis and X-ray micro-computed tomography. Water vapour permeability, capillary water absorption and mechanical strength of the materials were tested with standard methods. The results show that both ethanol and ovalbumin affect formation of phases, grout internal structure and porosity, and thus other related physical–mechanical properties. The grouts designed have properties that allow their potential for in situ implementation, with the advantage of water reduction. [ABSTRACT FROM AUTHOR]

The aim of this research was to evaluate solid state interaction between amoxicillin trihydrate andpotassium clavulanate. The interaction was observed by Differential Scanning Calorimeter (DSC),X-Ray Powder Diffractometer (XRPD), Fourier Transforms Infra Red (FTIR) and ScanningElectron Microscope (SEM). Mixtures of amoxicillin trihydrate and potassium clavulanate wereprepared in molar ratios of 0:10, 1:9, 2:8, 3:7, 4:6; 5:5; 6:4; 7:3; 8:2; 9:1; 10:0 and analyzed byDSC to obtain the thermal profile and a phase diagram. From this phase diagram, the molar ratiopoint of interaction was determined. XRPD analysis was performed to check the type of physicalinteraction occurred and FTIR was conducted to predict the chemical mechanism of interaction.Thermo profile obtained by DSC analysis of the binary systems showed that endothermic curves ofmolar fractions of 1:9—5:5 overlapped at 201°C. On the other hand, the diffractogram obtainedfrom Powder X-Ray analysis was very similar with that of amoxicillin trihydrate alone. FTIRspectrum of binary system in the molar ratio of 5:5 showed the loss of hydrate spectra fromamoxicillin trihydrate. We conclude that the interaction involved strong hydrogen bondingbetween hydrates of amoxicillin with potassium clavulanate which produced a co-crystal systemlike a solid dispersion.

In this study, a novel electrochemical sensor for quantification of ascorbic acid with amperometric detection in physiological conditions was constructed. For this purpose, cobalt and nickel ferrites were synthesized using microwave and ultrasound assistance, characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRPD), and used for modification of glassy carbon paste electrode (GCPE). It was shown that introducing these nanoparticles to the structure of GCPE led to increasing analytical performance. Co ferrite modified GCPE (CoFeGCPE) showed better characteristics toward ascorbic acid sensing. The limit of detection (LOD) obtained by sensor was calculated to be 0.0270 mg/L, with linear range from 0.1758 to 2.6010 mg/L. This sensor was successfully applied for practical analysis, and the obtained results demonstrated that the proposed procedure could be a promising replacement for the conventional electrode materials and time-consuming and expensive separation methods. [ABSTRACT FROM AUTHOR]

Simple route was used for synthesis of nanostructured titania samples doped with 3 and 6 mol% of Cr 3+ . Titanium(IV)-isopropoxide and water were used as starting materials and as an agents for controlling hydrolysis and condensation reactions. The phase evolution of titania (TiO 2 ) was followed by calcination at 400, 600 and 800 °C. The synthesized powders were examined by field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). Single-phase anatase was obtained at low temperature (400 °C) in all cases. The photocatalytic activity of TiO 2 doped nanopowders was evaluated by the photocatalytic degradation of crystal violet in aqueous solution. The present study indicates that this simple synthesis method can be an effective route to produce efficient photoactive doped anatase nanopowders. [ABSTRACT FROM AUTHOR]

Development of dielectric materials for microwave frequencies is increasing with rapid progress in mobile and satellite communications systems, where zinc titanates have found application due to their semi-conducting and dielectric properties. Mechanical activation by grinding is a well-known method and common part of the powder preparation route in the field of ceramics. The aim of this work is investigation of the influence of experimental conditions for mechanochemical synthesis of zinc orthotitanate. Starting powder mixtures of ZnO and TiO2, in the molar ratio that is in accordance with the stoichiometry of zinc titanate spinel type Zn2TiO4, were mechanically activated using a high-energy planetary ball mill. The process of mechanical activation was performed during different time intervals from 0 to 300 minutes. Microstructure characterization was determined by X-ray diffraction analysis and scanning electron microscopy. Also, the specific surface area (SSA) of powders samples was measured by a nitrogen gas sorption analyzer using the BET method. The very first traces of zinc titanate are detectable after only 5 minutes of activation. The most interesting occurrence during the mechanical method of activation is that we have an almost pure phase after 90 minutes.

The purpose of this study was to prepare solid SMEDDS (sSMEDDS) particles produced by spray-drying using maltodextrin (MD), hypromellose (HPMC), and a combination of the two as a solid carrier. Naproxen (NPX) as the model drug was dissolved (at 6% concentration) or partially suspended (at 18% concentration) in a liquid SMEDDS composed of Miglyol ® 812, Peceol™, Gelucire ® 44/14, and Solutol ® HS 15. Among the sSMEDDSs tested, the MD-based sSMEDDSs (with a granular, smooth-surfaced, microspherical appearance) preserved the self-microemulsifying properties of liquid SMEDDSs and exhibited dissolution profiles similar to those of liquid SMEDDSs, irrespective of the concentration of NPX. In contrast, HPMC-based sSMEDDSs (irregular-shaped microparticles) exhibited slightly prolonged release times due to the polymeric nature of the carrier. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and Raman mapping analysis confirmed molecularly dissolved NPX (at 6% of drug loading), whereas at 18% NPX loading drug is partially molecularly dissolved and partially in the crystalline state. [ABSTRACT FROM AUTHOR]

Betulinic acid (BA), a novel natural product with antimelanoma activity, has poor aqueous solubility (<0.1 μg/mL) and therefore exhibits poor bioavailability. The purpose of this study was to explore the feasibility of preparing BA solid dispersions (BA-SDs) with hydrophilic polymers to enhance the aqueous solubility of BA. Melt-quenched solid dispersions (MQ-SDs) of BA were prepared at various ratios with the hydrophilic polymers including Soluplus, HPMCAS-HF, Kollidon VA64, Kollidon K90, and Eudragit RLPO. BA was found to be miscible in all polymers at a 1:4 ( w/ w) ratio by modulated differential scanning calorimetry (MDSC). BA/Soluplus MQ-SD exhibited the highest solubility in simulated body fluids followed by BA/Kollidon VA64 MQ-SD. The MQ-SDs of BA/Soluplus, BA/HPMCAS-HF, and BA/Kollidon VA64 were found to be amorphous as indicated by X-ray powder diffraction (XRPD) studies. Fourier transform infra-red (FT-IR) studies indicated molecular interactions between BA and Soluplus. Our preliminary screening of polymers indicates that Soluplus and Kollidon VA64 exhibit the greatest potential to form BA-SDs. [ABSTRACT FROM AUTHOR]

Abstract: The high boron boride phase Mg2B25 was firstly discovered during the preparation of the superconducting MgB2 material by reacting liquid Mg at 850 °C with crystalline β-rhombohedral boron powders (Reactive Liquid Mg Infiltration process, Mg-RLI). This nonsuperconducting impurity phase was later on fully characterized from the crystallographic point of view by applying the Rietveld method on X-Ray Powder Diffraction (XRPD) diagrams of a pure powder sample. In this work we monitor the growing characteristics of the crystalline Mg2B25 and MgB2 phases during the Mg-RLI process, by implementing the XRPD analysis and other microscopic characterization techniques. In order to have a clear overview of what happens during the Mg-RLI process, we have varied the MgB2 preparative conditions: samples were prepared at 700, 850 and 900 °C adopting different heating times – 1, 3, 15 and 60 h – and various packing density of the starting boron powders (1.2, 1.4 and 1.6 g/cm3). We have used, as boron reactant, β-rhombohedral crystalline high purity powders, sieved at less than 100 microns. As far as the superconducting applications are concerned, the presence of residues of the Mg2B25 phase between the MgB2 crystalline grains, even if they are not superconducting, may lead to an improvement of the superconducting characteristics of the MgB2 in high magnetic fields by inducing – inside the MgB2 matrix – nano-defects which would be able to pin the current vortices developed in the superconducting state. [Copyright &y& Elsevier]

n extensive characterisation of the magnetic properties of synthetic powders of kuramite, with formal composition CuSnS, was performed. Powders were investigated through superconducting quantum interference device (SQUID) magnetometry, electron paramagnetic resonance (EPR) spectroscopy, X-ray powder diffraction (XRPD), scanning and transmission electron microscopies (SEM and TEM) and microanalysis. SEM and TEM reveal the presence of nanodimensioned particles. XRPD clearly shows that CuSnS crystallised in a cubic sphalerite-type structural model, in spite of the stannite-type tetragonal structure described for the natural phase. This difference arises from a full random distribution of cations. Synthetic kuramite nanopowders exhibit a marked paramagnetism, originated by the presence of Cu(II), definitely assessed by EPR measurements. Moreover, the overall magnetic behaviour of the sample cannot be simply ascribed to diluted paramagnetism, and this suggests the presence of strong superexchange interactions among Cu(II) ions even at room temperature. The main consequences of these results are the definitive assessment of the chemical formula Cu(I)Cu(II)SnS and of a random distribution of Cu(II), Cu(I) and Sn(IV) ions within the available tetrahedral sites. [ABSTRACT FROM AUTHOR]

Teeth are unique and complex anatomical organs that can provide relevant data about a person's health, and play an important role in forensic medicine. Teeth are exposed to food, drinks, and the microbiota of the oral cavity; therefore, they have developed a high resistance to localized demineralization. Nevertheless, the continuous demineralization–remineralization cycle present in the oral environment can be influenced by stress, medication, mineralization agents, and other factors such as individual habits, especially diet. In this study, based on attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) spectra from tooth samples of 36 patients, several parameters were estimated: the crystallinity index (CI), the phosphate/amide I ratio, and the carbonate/phosphate ratio. In addition, in eight representative samples (six of the root of the tooth and two of the enamel area of the crown), additional characterization by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) was conducted. From the FTIR data, it was observed that the highest CI values were found in patients who smoked. Further, in both root and crown samples, the intensity of the absorption band corresponding to PO43- increased in patients undergoing treatment with psychotherapeutic drugs. On the other hand, the intensity of the absorption band of the amide I group decreased with medical treatment and with the patient's biological age. Moreover, it was found that the remineralization process was more active in enamel than in the root due to direct contact with saliva. Regarding the results obtained from the X-ray powder diffractograms, exposure to psychotherapeutic drugs affected the definition of the peaks corresponding to hydroxyapatite, both in the crown and root samples. Concerning SEM results, qualitative differences in the stratification process in demineralized surfaces were observed, and EDS analyses showed some differences in the Ca/P ratio between pathological samples and control ones, but without clear patterns. The above techniques, in particular ATR-FTIR, showed promise for the investigation of the effect of changes produced in the hydroxyapatite structure in teeth and, consequently, to determine possible strategies in the diagnostic protocol. [ABSTRACT FROM AUTHOR]

Several million tons of Chromite Ore Processing Residue (COPR) were deposited at two sites in New Jersey and Maryland, USA, and over time they exhibited extensive heaving phenomena. Ettringite, a needle-shaped mineral and an expansive mineral commonly recognized in the literature concerning cement- and soil, has been identified extensively in numerous COPR samples collected from these sites. It was therefore believed that ettringite formation and its crystal growth are strongly associated with COPR heaving. We investigated the correlation between ettringite and the heaving phenomena in COPR materials that contained no initial ettringite. Two identical COPR samples were exposed to a 4% w/w sulfate solution (25°C, 50°C) in a confined swell test apparatus. Both swell test samples were analyzed by means of X-ray powder diffraction. The peak intensities of newly formed ettringite were more pronounced in the sample tested at 50°C, and swell development was only observed in this sample. Scanning electron microscopy analyses revealed well-crystallized ettringite needles exceeding 40 μm in length for this sample, while ettringite crystals less than 15 μm in length formed in the sample tested at 25°C. Therefore, the results suggest that the quantity of ettringite and the extent of crystallization play a key role in the heave of COPR. [ABSTRACT FROM AUTHOR]

This work exemplifies a general method of studying the drug excipient interactions, with the aim of predicting rapidly and inexpensively the long term stability of their mixtures. We study the physico-chemical properties of a drug (indomethacin) in the solid state and in different combinations with several excipients (PVP=polyvinylpyrrolidone, MGST=magnesium stearate, Avicel©). We compare the properties of pure compounds (untreated, or moisture/temperature conditioned) with those of binary mixtures drug:excipient which underwent the same treatment. The purpose is to find indications of interactions within the mixtures, which means a potential incompatibility of the excipient. Both morphological and thermal properties are sensitive to interactions which leave mostly unmodified the IR spectra and the X-rays patterns. In particular, we find that indomethacin does interact with PVP and MGST, but is certainly compatible with Avicel©. [ABSTRACT FROM AUTHOR]

We apply a range of techniques (thermal methods, microscopy, X-ray diffraction, IR spectroscopy) to characterize a drug (atenolol), several excipients (PVP=polyvinylpyrrolidone, MGST=magnesium stearate, Avicel©) and drug-excipients mixtures either as prepared, annealed, and exposed to moisture. We compare the data of the mixtures with those computed from a weighted average of similarly treated pure compounds to find evidence of drug properties modified by the interaction with the excipient. We find that thermal response is by far the most sensitive indicator of interaction while IR is the least sensitive one. Avicel© has essentially no interaction with atenolol, while MGST modifies significantly only the thermal response of the drug in the MGST-rich mixtures. PVP interacts strongly with atenolol, and this interaction appears to be mediated by the substantial amount of hydration water the excipient brings in its mixtures with a water-free drug. [ABSTRACT FROM AUTHOR]

In this study, two different dental ceramics, based on zirconia-reinforced lithium-silicate (LS1) glass-ceramics (Celtra Duo, Dentsply Sirona, Bensheim, Germany) and lithium disilicate (LS2) ceramics (IPS e.max CAD, Ivoclar, Vivadent, Schaan, Liechtenstein) were examined. They were tested prior to and after the crystallization by sintering in the dental furnace. Additionally, the impact of ageing on ceramic degradability was investigated by immersing it in 4% acetic acid at 80 °C for 16 h. The degradability of the materials was monitored by Impedance Spectroscopy (IS), X-Ray Powder Diffraction (XRPD), and Field Emission Scanning Electron Microscope (FE-SEM) techniques. It was detected that LS2 (vs. LS1) samples had a lower conductivity, which can be explained by reduced portions of structural defects. XRPD analyses also showed that the ageing increased the portion of defects in ceramics, which facilitated the ion diffusion and degradation of samples. To summarize, this study suggests that the non-destructive IS technique can be employed to probe the ageing properties of the investigated LS1 and LS2 ceramics materials. [ABSTRACT FROM AUTHOR]

Abstract Magnetite nanoparticles (NPs) were synthetized by partial oxidation of hot Fe(II) sulfate aqueous solutions upon addition of variable amounts of alkali/nitrate ions in a N 2 atmosphere. The resulting NPs were extensively characterized by Scanning Electron Microscopy (SEM), X-Ray Powder Diffraction (XRPD), Dynamic Light Scattering (DLS) and Brunauer-Emmett-Teller (BET) analysis. Depending on the final pH after synthesis, partially oxidized magnetite NPs were obtained with average crystallite size ranging from 29 to 116 nm. The potential of NPs as arsenic adsorbents was investigated through batch adsorption experiments. The analysis of the adsorption isotherms performed on the basis of both Freundlich and Langmuir models, revealed that arsenic adsorption capacity was more efficient for magnetite NPs synthetized at final pH ≤ 6.56, characterized by polydisperse submicrometric aggregates with coarse macro- and mesopore distributions. [ABSTRACT FROM AUTHOR]