X-ray Diffractograms Research Articles

Potency and Powder X-ray Diffraction (PXRD) Evaluation of Levothyroxine Sodium Tablets under Ambient, Accelerated, and Stressed Conditions.

Levothyroxine tablets, although highly prescribed in the United States, have been one of the most frequently recalled products. Because of the importance of the medication, several efforts have been put in place by the United States Food and Drug Administration (US FDA) to control the quality of levothyroxine tablets available to patients using the drug. The choice of excipients used in the formulation has been shown to impact the hygroscopicity and microenvironment, and ultimately the stability of the levothyroxine tablets formulations. Based on information generated from the US FDA Enforcement Report database, one of the main reasons for recalls is the low potency of different batches of the product. The yearly product recall trends for levothyroxine formulations were determined using the FDA Enforcement Report database. Three brands of levothyroxine tablets were selected with excipient lists similar to those products that have been historically recalled. The samples were placed at ambient (~23 °C), accelerated stability (40 °C/75% RH), and stress (50 °C/75% RH) conditions for up to 6 months. Sample potencies were determined at 0, 1.5, 3, and 6 months using the methods for assay and impurities in the United States Pharmacopeia (USP) monograph for levothyroxine tablets. Additional sample monitoring was conducted by overlaying the initial powder X-ray diffractograms (PXRD) of the samples from 0 months with the patterns generated thereafter. There has been a decline in the number of levothyroxine tablets recalled over the years. The highest numbers of recalls were recorded in the years 2013 [33] and 2020 [23]; no recalls occurred in the years 2019 and 2022. All of the brands evaluated met the USP 95.0-105.0% assay requirements at 1.5 months under accelerated conditions; only one of the brands complied at 3 months. Under ambient conditions, two brands were stable at 6 months, with borderline assay results. For stability, levothyroxine was found in microgram quantities in the formulations and PXRD could not detect changes at these low levels. However, we found some distinguishing data for samples under stress conditions.

Effect of parametric variation on the surface composition, structure, and tribological properties of zirconium nitride/oxynitride thin films

This paper evaluates the effect of parametric variation on the structure, surface composition and tribological properties of reactive RF-magnetron sputter deposited ZrN/ Zr2ON2 thin films. The properties of the films were investigated with respect to Ar: N2 flow rate, and power coupled to the plasma. X-ray photoelectron spectroscopy (XPS) revealed the presence of both the Zr2ON2 and ZrO2 stoichiometric components on the surface. Also, coupled power beyond 100 W promotes the formation of Zr2ON2 on the film surface. That’s why samples having thickness as low as 101–106 nm exhibit lower COF values 0.42–0.46 owing to the dominant presence of lubricating ZrO2 phase in the surface layer. Grazing angle X-ray (GIXRD) diffractogram exhibit that in the bulk, c-ZrN (311) and c-Zr2ON2 (440) phases are dominant. With increased power beyond 100 W, the (222) orientation of the Zr2ON2 phase also becomes significant, owing to enhanced reaction rate between the sputtered Zr and reactive gas atoms. Tribological studies show that the sample with the lowest surface roughness (S5) (∼114 nm) has the highest specific wear rate (∼1.26 ×10−3 mm3/ Nm). Colour of the films changed with applied power from grey at 50 W, to brownish yellow at 100 W, blue at 150 W, and golden yellow at 200 W. The films exhibited long term stability after 18 months of deposition, in terms of adhesion and colour, upon exposure to ambient condition.

Chemical, structural, microstructural, mechanical, and biological characterization of Ti–25Ta-xNb system alloys for biomedical applications

This study delves into the comprehensive characterization of the Ti–25Ta-xNb alloy system, whith a focus on its potential biomedical applications. Int intriguing insights into these alloys properties were unveiled through a systematic investigation encompassing EDS analysis, density measurements, chemical mapping, X-ray diffraction, microstructural examination, and microhardness assessments. The chemical composition results confirm that these alloys exhibit the appropriate stoichiometries, with the melting process yielding homogeneous compositions. Notably, the Ti–25Ta–10Nb and Ti–25Ta–20Nb alloys showcase the coexistence of α and β phases, while those with 30 % and 40 % Nb consist solely of the β phase, highlighting the β-stabilizing role of Nb and Ta. These results align seamlessly with X-ray diffractograms, Rietveld refinement data, and microstructural observations. The analysis further reveals a decrease in edges B and C of the α" structure, consistent with previous literature, indicating the alloys sensitivity to Nb additions. In terms of hardness, a discernible trend emerges with the stabilizing of the β phase, leading to reduced hardness values, as anticipated. Excitingly, not all alloys in the Ti–25Ta-xNb system exhibited cytotoxic effects, while they facilitated the crucial process of cell adhesion. This presents a promising prospect for their application in biomaterials. Among the developed alloys, the Ti–25Ta–30Nb alloy stands out due to its proximity to pure titanium in terms of hardness and its potential to promote cell proliferation.These findings underscore the potential of the Ti–25Ta-xNb alloy system for biomedical applications, provided that further studies optimize their suitability for such purposes.

Fractionation and physicochemical characterization of dietary fiber of kenaf (Hibiscus cannabinus L.) seed.

Kenaf seeds are underutilized kenaf plant by-products, containing essential nutrients including dietary fiber (DF), which can be potentially utilized as food ingredients. The present study aimed to evaluate the physicochemical characteristics of kenaf seed fiber fractions extracted from kenaf seed. Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions. These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.

Deciphering the Roles of Chemistry and Structure in Iridium Oxide Oxygen Evolution Catalysts through the Study of Annealed Iridium Oxide Nanoparticles

The development of proton exchange membrane (PEM) water electrolysis, which enables the production of de-carbonized hydrogen, is hindered by the low efficiency of the oxygen evolution reaction (OER). This is especially true in acidic environment where only noble metals (mainly Ru and Ir) can be used as electrocatalysts. Iridium oxide nanocatalysts (IrOx) are promising due to their high OER activity and good resistance to acidic and oxidative conditions. However, finding a compromise between their electrocatalytic activity and stability remains challenging. Moreover, it is not yet clear which parameter (the material structure1 or the initial iridium oxidation state2) controls these two properties.To address these challenges, we synthesized IrOx nanoparticles (NPs) supported on carbon (IrOx/C), through a modified polyol process, and annealed them under air, at temperatures ranging from 200◦C to 850◦C. This allows us to deconvolute the effects of the oxidation state, the structure and the size of IrOx NPs and to tune their activity and stability3. To analyze the structure, morphology, and oxidation state of Ir in these catalysts, we used transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and both laboratory-based and synchrotron-based X-ray diffraction (XRD) techniques.We observed in situ the crystallization of IrOx NPs, leading to crystallite size growth and change in Ir electronic state (see Figure 1a). Additionally, we investigated the morphological changes of IrOx NPs with respect to annealing temperature (refer to Figure 1b-f). We assessed their electrocatalytic activity towards the OER and determined their stability number4 (S-number) using inductively coupled plasma mass spectrometry and electrochemistry. We observed that increasing the annealing temperature led to an increase in particle size and degree of crystallinity, but did not result in significant changes in the iridium oxidation state (refer to Figure 1g). We observed the evolution of the electrochemical activity of the nanoparticles with the annealing temperature (see Figure 1h). Our results show a correlation between the changes in electronic structure, morphology, and size, and the evolution of OER activity and stability of the IrOx NPs. Specifically, we identified certain conditions that achieved an optimal balance between activity and stability.(1) Elmaalouf, M.; Odziomek, M.; Duran, S.; Gayrard, M.; Bahri, M.; Tard, C.; Zitolo, A.; Lassalle-Kaiser, B.; Piquemal, J.-Y.; Ersen, O.; Boissière, C.; Sanchez, C.; Giraud, M.; Faustini, M.; Peron, J. Nat. Commun. 2021, 12 (1), 3935. https://doi.org/10.1038/s41467-021-24181-x.(2) Claudel, F.; Dubau, L.; Berthomé, G.; Sola-Hernandez, L.; Beauger, C.; Piccolo, L.; Maillard, F. ACS Catal. 2019, 9 (5), 4688–4698. https://doi.org/10.1021/acscatal.9b00280.(3) Geiger, S.; Kasian, O.; Shrestha, B. R.; Mingers, A. M.; Mayrhofer, K. J. J.; Cherevko, S. J. Electrochem. Soc. 2016, 163 (11), F3132. https://doi.org/10.1149/2.0181611jes.(4) Geiger, S.; Kasian, O.; Ledendecker, M.; Pizzutilo, E.; Mingers, A. M.; Fu, W. T.; Diaz-Morales, O.; Li, Z.; Oellers, T.; Fruchter, L.; Ludwig, A.; Mayrhofer, K. J. J.; Koper, M. T. M.; Cherevko, S. Nat. Catal. 2018, 1 (7), 508–515. https://doi.org/10.1038/s41929-018-0085-6.Acknowledgments: This work was supported by the French National Research Agency in the frame of the MATHYLDE project (grant number n° ANR-22-PEHY-0001).Figure 1 – a. X-ray diffractograms obtained on IrOx/C annealed at 290, 340, 380, 420, 470, 520, 570, 620, 670 and 850°C under air. Each measurement lasted 13 minutes. The hashes correspond to tetragonal IrO2 (PDF card 00-043-1019) and the stars to metallic Ir (PDF card 00-006-0598). b-f. TEM images of IrOx/C NPs as-synthesized and calcined at 290, 380, 420, 570 and 850 °C. g. X-ray photoelectron spectra showing the Ir 4f levels of IrOx/C NPs as-synthesized and calcined at 380, 420, 520 and 850 °C. The dotted lines indicates the theoretical position of the peaks for Ir(IV) and Ir(III). h. Cyclic voltammograms measured in 0.1 M HClO4 at 50 mV s−1 indicating the change in electrochemical properties of IrOx/C NPs with annealing temperature. Figure 1

Microstructure and chemical composition of deposited particulate matter from gasoline and diesel vehicle exhaust emissions

A comprehensive physicochemical characterization of transport-emitted aerosols containing in vehicle exhaust emissions derived from the combustion of fuels such as diesel, premium gasoline, and unleaded gasoline was performed in this study by employing a range of analytical techniques (Laser granulometry, X-ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), X-ray diffraction (DRX), Scanning Electron Microscopy (SEM), and Thermogravimetry). The X-ray diffractogram of diesel (D) derived aerosols showed an amorphous structure while those of unleaded gasoline (UG) and premium gasoline (PG), showed amorphous crystalline phases. The chemical composition of D, PG and UG derived particles was dominated by aliphatic C-H groups of alkanes with relatively low C=O groups of carboxylic acids, ketones, aldehydes, esters, lactones, and sulphate (SO4 2-) inorganic salts. The nitrogen-containing functionality (NO3-) was specific to particles of PG and UG. Laser particle size analysis showed fine particle sizes (Range) generated from diesel exhausts, thus making them dangerous when inhaled, as they can penetrate deeply into the human airways and become incorporated into the blood stream damaging other viscera.

Heat Treatment Effect on Thermal, Micro-Crystal Structure and Magnetic Behavior of Ni45Mn40Sn10Cu5 Heusler Shape Memory Alloy

Ni-Mn-Sn-based Heusler alloys are important materials that have potential applications as environmentally friendly smart materials with beneficial properties as well as being magnetic. Both the magnetic field-induced reverse martensitic transformation and the high operating temperature are crucial for the applications of Ni-Mn-Sn-based magnetic shape memory alloys. In this study, martensite transformation temperatures were determined by applying different heat treatments (700 °C, 900 °C, 1100 °C) to Ni45Mn40Sn10Cu5 sample produced by Arc Melter melting method. While reverse conversion was observed in T2 (no heat treatment) and 700°C heat treatment, no reverse conversion was observed at 900°C and 1100°C. When the X-ray diffractogram was examined, martensite phase and γ phase were determined. When the magnetic hysteresis of the samples was examined, it was observed that the magnetic saturation went towards zero with the increase in heat treatment and accordingly, there was a decrease in the magnetization effect.

Evaluation of dual modification by high hydrostatic pressure and annealing on the physicochemical properties of bean starch

This study investigated the physical modifications by high hydrostatic pressure (HHP) at 600 MPa for 30 min/30 °C, annealing (AN) at 50 °C/24 h and the combination of both (HHP + AN and AN + HHP) applied to yellow bean starch to verify changes in morphology, X-ray diffraction, molecular order, thermal properties and pasting properties of native (NS) and modified starches. Morphological analysis showed loss of sphericity and increase in diameter with the appearance of pores on the surface after application of treatments. The AN starch showed lower values of syneresis, degree of double helix (DD), order (DO), and viscosity of the paste obtained by RVA. It exhibited a Vh-type classification with the appearance of the amylose–lipid complex. However, the gelatinization temperatures, as well as the enthalpy of gelatinization, were significantly higher. On the other hand, the starch treated with HHP showed a higher Setback (SB) value. The greatest modifications were found for the starches subjected to the combined treatments (AN + HHP) and (HHP + AN), where the order of the treatments was significant for the morpho-structural changes of yellow bean starch. According to the micrographs, the surface aspect was altered, with AN + HHP showing greater irregularities and flat yet irregular faces, as well as a larger granule diameter (147.05). The X-ray diffractogram showed a reduction in crystallinity from 28.14 % (NS) to 18.09 % (AN + HHP) and classified the starch as type “A”. The double modification (HHP + AN and AN + HHP) reduced the gelatinization temperature and the enthalpy of gelatinization but had no effect on the bands of the FT-IR spectrum. There was only a reduction in the degree of order and the double helix. Finally, the treatment with AN + HHP is more effective as the gelatinization with AN facilitates the application of HHP. Both methods used are classified as physical (thermal and non-thermal), aiming to minimize environmental impacts and achieve faster and safer morpho-structural modification without leaving chemical residues in the products.

Microwave radiation assisted synthesis of NiFe2O4-CoFe2O4 nanocomposites for photocatalytic and photoelectrochemical water splitting applications

Microwave radiation assisted method is emerged as a promising method due to its environmental friendliness, less time and no need toxic or harsh reagents. Herein, we report the synthesis of a NiFe2O4-CoFe2O4 nanocomposites by microwave radiation assisted method and its characterisation using various methods. X-ray Diffractogram (XRD) studied revealed the spinel cubic structure of the NiFe2O4-CoFe2O4 nanocomposites having an average crystallite size of 34 nm. Tetrahedral (594 cm−1) and octahedral (397 cm−1) sites of NiFe2O4-CoFe2O4 are identified by Fourier Transform Infrared (FTIR) spectroscopy as it is having the typical vibrational frequencies. UV–Visible diffuse reflectance (UV–Vis DRS) spectrum indicated that optical bandgap is less for nanocomposites compared to individual components. Transmission electron microscopy (TEM) images show the spherical nature of the nanocomposites. The photocatalytic degradation study of microwave-assisted NiFe2O4-CoFe2O4 nanocomposites is investigated under visible light irradiation against the Rose Bengal and Methylene blue dyes. The developed nanocomposites exhibited enhanced photoelectrochemical hydrogen due to higher charge separation and faster charge transfer at the interface.

Influence of La3+-Co2+ substitution on X-band microwave absorption properties of Ba0.5Sr0.5Fe12O19 nanoparticles with insight into quarter wavelength phenomenon

The presented study aims to tune the microwave absorption properties by varying the chemical composition of Ba0.5Sr0.5Fe12O19 nanoparticles with Co–La substitution via the synthesis route of the sol-gel citrate precursor method. X-ray diffractograms (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR) confirmed the formation of pure phase M-type hexagonal ferrite with varying lattice parameters. The permittivity measurements revealed increased dielectric losses, indicating good energy dissipation behavior. Enhancement of magnetic behavior resulted from the strengthened exchange interactions between lattice sites, leading to higher permeability values. Significant reflection losses were exhibited by our synthesized samples with a maximum reflection loss of −42.08 dB at 4.62 GHz for x = 0.35 at an experimental thickness of 3 mm. The dependence of reflection loss peaks on matching thickness was analyzed using calculated thickness profiles, revealing their close agreement with simulated thickness. The study highlighted the potential of synthesized samples for electromagnetic signature reduction, in both commercial and military applications.

The potential exploitation of the Malay-red apple (Syzygium malaccense) seed as source of a phosphorylated starch

This work presents the characterization of a novel naturally phosphorylated starch extracted from an unconventional and non-utilized source, the seeds of the stone fruit Syzygium malaccense. The morphology and chemical characteristics of the extracted starch were examined by scanning electron microscopy, FTIR, 1H/13C/31P NMR and 13C-CP/MAS-NMR, HPAEC-PAD chromatography, XRD, DSC, and RVA. The extraction yielded a highly pure starch (95.6 %) with an average granule size of 13 μm. The analysis of the starch components revealed an amylose content of 28.1 % and a predominance (65 %) of B-chains (B1–B3 65 %) in the amylopectin, as shown through HPAEC-PAD chromatography. The X-ray diffractogram was compatible with B-type starch, which was confirmed by the deconvolution of the C1 peak in the 13C-CP/MAS-NMR. X-Ray diffractogram also showed that S. malaccense has 28.5 % of crystallinity. DSC analysis showed values of 82.6 °C and −12.41 J g−1 for Tc and ΔH, respectively, which is compatible with a highly ordered starch granule structure. The values observed for peak (4678 mPa•s), trough (3055 mPa•s), and final viscosity (6526 mPa•s) indicated that S. malaccense may be used as a thickener in hot food.

Effect of Cobalt Doping on the Dielectric Properties and Electrical Conductivity of Nickel Tungstate

The study investigates the influence of cobalt doping on the structural and dielectric properties of NiWO4. Pristine and Co-doped nickel tungstate samples are synthesized via the direct chemical precipitation method. X-ray diffractogram is employed to analyze the structural variations introduced by doping. The impact of doping on dielectric properties is analyzed by examining the frequency response curves of the dielectric constant's real part and the loss tangent. Nyquist curves are used to study the relaxation process and the conduction mechanism taking place within pure and doped samples. An equivalent circuit is formulated and analyzed based on impedance spectroscopy to examine the physical processes occurring within the pure and doped samples. The introduction of cobalt dopants in the lattice of nickel tungstate results in a change in the conduction mechanism of nickel tungstate, leading to higher conductivity in the Co-doped nickel tungstate samples. Co-doping improves the electrical properties and conductivity of nickel tungstate and makes it a promising candidate in microelectronic devices.[copyright information to be updated in production process]

Nickel-based composites using tungsten carbides as enhancers for electroactivity for the hydrogen evolution reaction

This study explores the impact of incorporating tungsten carbides into a Watts bath on the fabrication of Ni/WC and Ni/W2C composites, comparing them with conventional Ni Watts electrodeposited electrodes. Results indicate that adding tungsten carbides to the conventional nickel bath forms rougher and more porous structures in the deposited composites. Composite electrodes exhibit significantly enhanced current density for hydrogen evolution in alkaline media compared to nickel Watts electrodes. Differential Electrochemistry Mass Spectrometry (DEMS) elucidates the hydrogen evolution mechanism, providing accurate data for Tafel plots. X-ray photoelectron spectroscopy (XPS) shows minimal impact on nickel's surface chemistry. X-ray diffractograms demonstrate that tungsten carbide particles maintain crystalline structure. X-ray dispersive spectroscopy (EDS) reveals an uneven chemical composition, with Ni/WC and Ni/W2C composites containing approximately 17% tungsten carbides. Electrochemical impedance spectroscopy (EIS) indicates higher electrochemical areas and lower charge transfer resistances in Ni/WC and Ni/W2C composites than in Ni Watts. This study contributes insights for the efficient and economical development of electrolysis systems. Notably, Ni/WC and Ni/W2C composites show promising electrochemical performance, emphasizing their potential in advancing electrolysis technology.

Influence of iron substitution on structural, magnetic, and magnetocaloric properties of Tb2Fe17−xAlx compounds synthesized by arc melting

In the present work, the structure and magnetic and magnetocaloric properties of the Tb2Fe17−xAlx compounds with x=0,0.25,0.5,0.75, and 1 were studied. These compounds were synthesized by arc furnace without subsequent annealing. Their crystal structure is a Th2Ni17 hexagonal structure with a P63/mmc space group. The Rietveld refinement of the X-ray diffractograms allowed for determining the structural parameter variations with different amounts of aluminum. Lattice parameters and the unit cell volume increase with aluminum amounts while the c/a ratio remains nearly constant. The Tb2Fe17−xAlx compounds exhibit a second-order magnetic phase transition from a ferromagnetic state to a paramagnetic state. The Curie temperature (TC) increases with the aluminum content, the observed effect is due to the magnetovolumic effect. The saturation magnetization (MS) decreases with the increase of Al content. Magnetic entropy and relative cooling power (RCP) decrease as the aluminum content increases. Tb2Fe17−xAlx compounds have a moderate magnetocaloric effect and a tunable operating temperature interval.

A new galactomannan extracted from the seeds of Astragalus gombiformis Pomel (Fabaceae) and its utilization in the biosynthesis of silver nanoparticles

Finding novel sources of polysaccharides with suitable properties for desired uses in numerous sectors, such as nanotechnology, is becoming a more active area of research. Galactomannan (AGFPG) from the seeds of Astragalus gombiformis Pomel (Fabaceae) was extracted and characterized, and its potential application in the biosynthesis of silver nanoparticles (AgNPs) was investigated. The yield after hot water extraction was 10.4% (w/w), and the total carbohydrate content was 83.09 ± 0.03% (w/w). High-performance liquid chromatography and nuclear magnetic resonance revealed that AGFPG was composed of β-D-mannose (60.05%) and α-D-galactose (39.95%), with a Man/Gal ratio of 1.51. Biosynthesis was confirmed by the absorption peak of AgNPs at 423 nm. Scanning electron microscopy images and X-ray diffractogram revealed the spherical shape and the crystalline structure of AgNPs. A Zeta potential value of AgNPs − 48.6 mV showed their high stability. The hydrodynamic diameter of AgNPs by Dynamic light scattering is 144.4 nm. The AgNPs showed significant antimicrobial activity and antioxidant activity (DPPH and Ferric reducing power). AGFPG, as a new galactomannan, can be used as a reducing and capping agent. Biosynthesized AgNPs exhibit good antimicrobial and antioxidant activities, which has led to their use in a variety of fields.

Addressing the effect of stacking faults in X-ray diffractograms of graphite through atom-scale simulations

Determining the average contribution and actual distribution of rhombohedral stacking sequences within the average graphitic crystallite remained unsolved. To address this issue, we used a bottom-up approach to simulate X-ray diffractograms of graphite crystallites up to one million atoms in various graphene stacking configurations to find out how to match experimental data. The 100–101 2θ range was highly sensitive to the presence of C layers and can be used to accurately characterize the stacking disorder. On the opposite, the 110–112 2θ range was not sensitive to stacking disorder and thus can be taken as a reference to obtain the average in-plane size La of the crystallites, faulted or not. We used the principle of the L'c parameter, introduced in a former work, which corresponds to the height of the coherent sub-domains within the average crystallite obtainable through the shape of the hkl peaks involving both in-plane and out-of-plane directions. Three types of defects within a Bernal sequence were analyzed, which do not affect the peaks the same way: (i) a substitution of A or B by C, (ii) an insertion of C leading to destructive interferences, and (iii) a so-called "block shifting". It is thus possible to go further in the interpretation of X-Ray diffraction. Finally, we discussed how the overall crystallite size Lc can be obtained from all the 00l peaks.

Study of the influence of calcium fluoride on the bioactivity of boron-based glass

This work aimed to evaluate the influence of CaF2 addition in the bioactivity of the samples. The system 60B2O3-4P2O5-18Na2O-xCaF2-(18-xCaO), with x= 0, 5 and 10 wt% was synthetized by melt-quenching method. The in vitro bioactivity of the glasses was investigated by X-ray diffractogram (XRD), Raman, Fourier transform infrared spectroscopy (FTIR) and pH after immersion in SBF solution during 28 days. Results of pH presented an increase after 24 hours of soaking in SBF, which contributes to the dissolution of the external layer of the glass and precipitation of apatite. Hydroxyapatite and fluorapatite formation was confirmed by XRD patterns, Raman and FTIR spectra, confirming the bioactivity of the samples. Cytotoxicity tests were performed on osteoblastic cells. All the samples presented cytotoxicity smaller than 10%, and induced the osteoblast proliferation, indicating a good cytocompatibility and good cell viability. Therefore, the glasses have potential to be applied in biomedical applications, such as odontology and tissue engineering.

Innovative Method for the Mass Preparation of α″-Fe16N2 Powders via Gas Atomization

The iron nitride materials, especially α″-Fe16N2, are considered one of the most promising candidates for future rare-earth-free magnets. However, the mass production of α″-Fe16N2 powders as a raw material for permanent magnets is still challenging. In this work, starting from iron lumps as a raw material, we have managed to prepare the α″-Fe16N2 powders via the gas atomization method, followed by subsequent nitriding in an ammonia–hydrogen gas mixture stream. The particle size was controlled by changing the gas atomization preparation conditions. X-ray diffractograms (XRD) analyses show that the prepared powders are composed of α″-Fe16N2 and α-Fe phases. The α″-Fe16N2 volume ratio increases with decreasing powder size and increasing nitriding time, reaching a maximum of 57% α″-Fe16N2 phase in powders with size below 32 ± 3 μm after 96 h nitridation. The saturation magnetization reaches the value of 237 emu/g and a reasonable coercivity value of 884 Oe. Compared to the saturation magnetization values of α-Fe powders, the α″-Fe16N2 powders prepared through our proposed approach show an increase of up to 10% in saturation and demonstrate the possibility of mass production of α″-Fe16N2 powders as precursors of permanent magnets without rare earths.

Facile Synthesis of PVP-Coated Silver Nanoparticles and Evaluation of Their Physicochemical, Antimicrobial and Toxic Activity

This study focuses on the synthesis of silver nanoparticles (AgNPs) at different high concentrations and investigates their physicochemical properties, antimicrobial activity, and cytotoxicity. AgNPs were synthesized using the alcohol reduction process, involving the reduction of AgNO3 and its subsequent stabilization via PVP at 80 °C for 4 h. The AgNO3/PVP molar ratio and the average molecular weight were modified in this study. Characterization analyses revealed that the synthesized AgNPs exhibited characteristic surface plasmon resonance absorption peaks at approximately 415 nm, as observed in the UV–Vis spectrum. The results presented in X-ray diffractograms confirmed the face-centered cubic structure of metallic Ag in the nanoparticles. The nanoparticles demonstrated uniform size and shape, with controllable dimensions ranging from 3 to 800 nm. Regarding antimicrobial activity, the MIC solutions exhibited higher potency against the planktonic cells of Candida albicans. The determination of inhibition halos indicated that the silver nanoparticles had an impact on the microorganisms Streptococcus mutans, Candida albicans, and Actinomyces israelii. Furthermore, lower-concentration compositions showed reduced cytotoxic effects compared to higher-concentration particles. Based on the findings, it was concluded that the AgNO3/PVP molar ratio plays a crucial role in the production of AgNPs. These synthesized nanoparticles exhibit desirable physicochemical properties and demonstrate potential antimicrobial activity and controlled cytotoxicity.

Synthesis and optical characterization of Fe doped Barium Titanate (BaTiO3) nanoparticles

The perovskite family includes a variety of titanates used in a variety of electrical ceramic applications such as electronic, electro-optical and electro-mechanical ceramic applications. Barium Titanate (BaTiO3) is a member of a large family of compounds with the general formula ABO3 called perovskites. This paper includes the study of the properties of pristine and Iron (Fe) doped Barium Titante (BTO) at different concentrations synthesized using the sol–gel method. The concentration of dopants varies from 0 to 3 mol% in the specimens. The structural, surface morphology and optical properties of pure and Fe ion doped Barium Titanate nanoparticles have been investigated using X-ray diffraction (XRD), UV–Visible spectroscopy and Photoluminescence spectroscopy. X-ray diffraction (XRD) was used to study the structure and crystallite size of BTO nanoparticles. The results from X-Ray diffractogram shows that the particle size lies in the range 23 to 29 nm. Lattice strain of each samples were calculated using Williamson-Hall plot (WH plot). Bandgap energy of the samples were calculated using UV– Visible spectroscopy. For pristine BaTiO3 the bandgap is found to be 3.23 eV. It is observed that as the doping percentage increases the bandgap of the material decreases. Photoluminescence measurements revealed that the specimen show ultraviolet emission along with emission in blue region.