X-ray Diffractograms Research Articles

Nitrogen ion beam induced modifications on the properties of carbon quantum dots/TiO2 nanocomposite

The present study reports the modifying the properties of carbon quantum dots/titanium dioxide (CQDs/TiO2, termed as CT) nanocomposite by Nitrogen (N+) ion beam irradiation in the energy range of 10 keV–40 keV at a fluence of 3 × 1015 ions cm−2. Transmission electron microscopic results reveals the anchoring of (3–5) nm CQDs on TiO2 nanoparticles of size ∼25 nm. UV–Visible spectroscopic results show the decrease in the bandgap of CT nanocomposite after N+ ion irradiation. X-ray Diffractogram exhibits the shift in the planes of CT nanocomposite due to irradiation. X-ray photoelectron spectroscopic results indicate the presence of nitrogen functional groups after irradiation. Raman spectroscopy results reveal the enhancement in disorder parameters due to irradiation-induced large number of small sp2 domains of carbon. Photoluminescence spectroscopy results show the decrease in emission intensity of CT nanocomposite after irradiation due to suppression in the recombination rate of photoexcited electron-hole pairs. The work function of CT nanocomposite decreases after ion irradiation indicating the shifting of Fermi energy level towards conduction band as studied by Ultraviolet photoelectron spectroscopy. Photoelectrochemical measurement studies reveals that improvement in the photoelectrochemical performance of 40 keV N+ ion irradiated CT compared to TiO2.

Mixed oxides from calcined layered double hydroxides for glycerol carbonate production to contribute to the biodiesel economy

The glycerol generated as a by-product in the production of biodiesel could be used as a renewable raw material to economically promote the production process. The catalytic conversion of glycerol to a product with higher added value, such as glycerol carbonate, has attracted great interest in the chemical, pharmaceutical, and lithium battery industries, among others, due to its low toxicity, hydration capacity, and biodegradability. Layered-double hydroxide (LDH) materials, the precursors of the catalysts, were synthesized by a direct coprecipitation method to incorporate a third metal ion in addition to magnesium and aluminum ions. This method is the easiest regularly applied technique to design these low cost anionic nanoclay. The atomic percentage of Cu, Zn, or Ni incorporated was 15% of the Mg load in the material. The synthesis atomic ratio, (M2++Mg2+)/Al3+ had a constant value of 3, where M represents the transition metal incorporated. LDHs produced the corresponding mixed metal oxides by thermal decomposition. These materials have excellent properties for reactions catalyzed by the basic sites, high surface area, homogeneous cation dispersion, and thermal stability. The physicochemical material properties were characterized by XRD, N2 sorption, MP-AES, TPD-CO2, SEM, and XPS. The mixed oxides were evaluated in the catalytic conversion of glycerol to glycerol carbonate. The addition of Cu, Ni, or Zn to the matrix of Mg and Al produced changes in its physicochemical properties and mostly in the catalytic activity. X-ray diffractograms of LDHs showed the typical characteristic structure of layers even with metallic ions of Cu, Ni, or Zn incorporated, because their ionic radii are similar to that of the Mg ion, 0.69, 0.73, and 0.74 Å, respectively. The obtained mixed oxides showed a high catalytic activity towards the conversion of glycerol to glycerol carbonate under mild reaction conditions, a 1:2 ratio of glycerol:ethylene carbonate and solvent free. Relative yields higher than 80% were obtained, attributable to an adequate distribution of basicity and textural parameters. The catalysts were used in successive reaction cycles without significant loss of activity.

The optimization of silica gel synthesis from chemical bottle waste using response surface methodology

To reduce the amount of hazardous chemical bottle waste in the environment, we report the optimization research of silica extraction in chemical bottle waste into silica gel. Alkali fusion and sol–gel process were utilised to prepare silica gel effectively. The alkali fusion process was carried out by adding sodium hydroxide to produce sodium silicate. Afterwards, silica gel was prepared by the sol–gel method using hydrochloric acid. Box-Behnken Design (BBD) was applied to Optimisation factors the poptimiseactors affecting the silica recovery. The factors that optimised mass ratio, particle size, and temperature. The optimum recovery of silica gel was obtained by SiO2: NaOH mass ratio of 1:3, the particle size of 63–74 µm, and a temperature of 800 °C. The purity of silica gel optimum is 63.74% characterised using X-ray fluorescence. The structure of silica gel is the appearance of amorphous peaks at 2θ 20-30° characterised using an x-ray diffractogram. The silica gel surface was characterises using scanning electron microscopy-energy dispersive x-ray. It showed an irregular surface and characteristic showed that silica gel had a radius of 15.74 nm and a specific surface area of 297.08 m2.

Effects of different Bismuth concentrations of InSbBi crystals grown by Bridgman technique

InSb1-xBix (x = 0, 0.005, 0.010, 0.015) crystals are grown by vertical Bridgman technique using single-zone resistive heating furnace. The main objective of this paper is to study the improvement of thermoelectric quality factors by different concentrations of Bismuth (Bi) in InSbBi crystals. EDAX (Energy Dispersive Analysis of X-rays) confirms that the grown crystals are pure and show the presence of In, Sb, and Bi in proportion. Powder X-ray diffractogram confirms the cubic zinc blend structure of these crystals with space group F-43m and all the diffraction peaks are matched well to the standard JCPDS-ICDD No. 6-0208. Raman spectra are recorded from 80 K to 300 K and Raman mapping spectra at room temperature for all above crystals have shown the presence of TO mode at 179.91 cm−1 and LO mode at 190.16 cm−1. The sharpness and intensity of Raman spectra have clearly reflected the purity and quality of the grown crystals. The electrical conductivity σ is found to increase slowly upto 450 K and then increases linearly upto 600 K and above that, it gets saturated in all crystals. The Seebeck coefficient remains negative showing that these crystals are n-type semiconductor and its value is found to be increased to −200 μV/K for InSb0.985Bi0.015 in comparison to −150 μV/K for pure InSb near 600 K. From the lattice thermal conductivity, power factor and thermoelectric figure of merit i.e. ZT calculations, it is concluded that InSb0.985Bi0.015 at 670 K gives the highest value of ZT = 0.45 in comparison to other grown crystals.

Facile chemical modification of Nb2CTx MXene with ethylene diamine for sensitive electrochemical detection of dopamine from human serum samples

• We present a facile method for the synthesis of aminated Nb 4 C 3 T x derivative through facile amination technique. • The amination of Nb 4 C 3 T x can enhance the electrochemical response • The aminated Nb 4 C 3 T x exhibited the highest sensing response towards dopamine in linear range of 1 nM – 100 μM. • The detection limit of the developed sensor reached as low as 300 pM. • The real sample analysis showed excellent agreement with the experimental results The electrochemical detection of dopamine (DA) is of ultimate importance in the early-stage diagnosis of Parkinson's and Alzheimer's diseases. In this work, we report the development of a facile amination technique of Nb 2 CT x MXenes for the electrochemical sensing of DA. The amination was confirmed using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy the structural changes due to the amination process were confirmed using X-Ray diffractograms. The modified MXenes were used to modify carbon cloth electrodes, which were then applied to the electrochemical detection of DA. The developed sensor was able to detect dopamine linearly in the range 1 nM–100 μM and a limit of detection of (LOD) of 300 pM was achieved. The modified electrode was found to have a selective response to DA in the presence of other interferents in addition to being reproducible and stable. The modified electrode was also used for the detection of DA in serum samples with little difference in the sensing characteristics in phosphate buffer. This work presents a novel amination route for the surface functionalization of Nb 2 CT x and opens new avenues for applications of surface functionalized Nb-MXenes in electrochemical detection of neurotransmitters.

Sporosarcina pasteurii-induced hydration and shrinkage properties of Portland cement

The present study explored the Sporosarcina pasteurii-induced hydration and shrinkage properties of Portland cement. Bacterial culture solutions were incorporated into cement samples at varying dosages. The hydration properties of the fabricated samples were investigated through compressive strength tests, X-ray diffractograms, thermogravimetric analyses, and water absorption tests. In addition, autogenous and drying shrinkage measurements were carried out to monitor the volumetric changes of the samples with different bacteria contents. The test outcomes identified that the incorporation of bacteria retarded the progress of early hydration while promoting the reaction at a later stage by internal carbonation accompanied by the CO32− released by the bacteria. The internal carbonation was particularly effective in enhancing the reaction degree of belite, which produced more CSH. The microstructural modification of the samples by CaCO3 precipitation reduced the water absorption level and mitigated the development of drying shrinkage.

Yttrium doped ZnO nanofillers reinforced epoxy coating for anticorrosion application

In the present study, synthesized pure and Yttrium (0.5, 1.0, 1.5, 2.0 and 2.5 mM) doped Zinc Oxide (YZO) nanoparticles by chemical precipitation method. X-ray diffractogram asserts the hexagonal wurtzite structure of ZnO nanoparticles. The average crystallite size was found to be 22–17 nm. The hexagonal shape, surface morphology, particle size and elemental composition of the samples were analyzed by FESEM, HRTEM and EDAX. The anticorrosive property of nanoscopic size (17 nm) YZO/epoxy nanocomposite was studied by electrochemical impedance spectroscopy (EIS) technique in both neutral and acidic media. Epoxy/YZO nanocomposites were prepared using different loadings (0.05, 0.10 and 0.15 wt%) of yttrium doped ZnO nanoparticles. The results obtained confirm that 0.10 wt% is the optimum concentration to get superior anticorrosion activity Epoxy/YZO nanocomposites were applied on mild steel substrates. The acquisition of yttrium doped ZnO nanofillers into the plain epoxy coating materially increased the charge transfer resistance Rct by 3.5 times in oxalic acid solution as against epoxy/ZnO coating. This encapsulates that the YZO nanoparticles are a potential anti-corrosive filler in coat on mild steel.

Effect of annealing temperature on structural, optical, magnetic and electrical properties of CrFeO3 multiferroic nanoparticles: A validation to first-principle calculations

Recently, room-temperature multiferroic materials have attracted great interest as they are suitable for the design of low-power electronic and spintronic devices. In this paper, we have investigated the effect of annealing temperature on the structural, electrical and magnetic properties of CrFeO3 multiferroic nanoparticles prepared by sol-gel auto-combustion method. The structural properties by observing X-ray diffractogram and its thorough Rietveld refinement confirmed the trigonal crystal structure with space group R3̅. The crystallite size calculated from the W-H plot increases from 39.6 nm to 100.5 nm with the increase of annealing temperature. FTIR results confirmed the evolution of ilmenite type ABO3 phase. Electron microscopy images showed increase of grain size due to agglomeration of nanoparticles at higher annealing temperature. EDXA spectra and color mapping demonstrated the elemental purity. Magnetic measurements revealed the antiferromagnetic nature of CrFeO3 multiferroic nanoparticles. Electrical measurements showed the decrease in dielectric constant with the increase in frequency. We have validated the results by running systematically first-principle calculations (Density Functional Theory) on CrFeO3 multiferroic nanoparticles.

Development of a TiO2/Sepiolite Photocatalyst for the Degradation of a Persistent Organic Pollutant in Aqueous Solution.

A clay-based TiO2 nanocomposite material was synthesized by a facile method, to investigate its structure and photocatalytic efficiency. The supported TiO2 nanoparticles were generated using a sol-gel method, and subsequently, mixed with a suspension of sepiolite. The material was recovered in powder form (Mc-80) and then calcined to properly arrange the crystal lattice of the TiO2 particles for use in heterogeneous photocatalysis (Mc-80-500). A powder X-ray diffractogram of Mc-80-500 revealed a dispersion of anatase and rutile phase TiO2 particles on the clay surface, exhibiting a size in the order of 4–8 nm. TEM images of Mc-80-500 confirmed the presence of isolated TiO2 beads on the surface of the fibrous sepiolite. The specific surface area of Mc-80-500 was larger than that of raw sepiolite and that of free TiO2 nanoparticles. Mc-80-500 was found to be more efficient in heterogeneous photocatalysis compared to other TiO2 materials based on sepiolite. Total depollution of a reactive dye (Orange G) was achieved after 1 h irradiation time, which is relatively quick compared to previous reports. The photocatalyst material can be washed with distilled water without chemical additives or calcination, and can be reused several times for photocatalysis, without loss of efficiency.

PdNP@Cyclodextrin on Cu/Al LDH-containing nanocomposites: Cage effect, crystallite size tuning and composite topology towards cross-couplings

A series of Cu/Al layered double hydroxides and Pd(0/II) composites containing native and modified cyclodextrins were prepared under different conditions of solvent (water or N,N-dimethylformamide), Pd precursors (Na2PdCl4 or Pd2dba3) and cyclodextrin/Pd ratios for the catalytic evaluation in Pd/Cu catalyzed cross-couplings aiming for the preparation of aryl thiophenes and N-arylamines. According to XPS measurements, the nanocomposites prepared in water presented a higher Pd(II)/Pd(0) ratio and subtle evidence of [PdCl4]2− intercalation by analyses of X-ray diffractograms. On the other hand, those prepared in N,N-dimethylformamide showed a higher content of Pd(0), probably dispersed on layered double hydroxides surface. SEM-FEG analyses combined with particle size distribution revealed that cyclodextrins were able to tune the size distribution, especially the β-form (15 nm in the presence of cyclodextrins). Powder X-rays diffraction data refinement using Rietveld method revealed that controlled palladium crystallite sizes of 11.53 nm and 10.22 nm were obtained in the presence of hydroxypropylated cyclodextrins (β and γ forms). Notably, the Rietveld refinement of the Pd nanocomposites revealed the presence of malachite, gibbsite, and sperniite phases in 23.05%, 23.05%, 15.23% contents. It suggests that Pd introduces a distortion in the initial LDH lattice. The catalytic activities of these nanocomposites were evaluated in Suzuki-Miyaura reaction in water/ethanol mixture, under low Pd loadings and room-temperature. Noteworthy, the nanocomposite prepared in N,N-dimethylformamide with native β-cyclodextrin showed higher catalytic activity (turnover number up to 7379) in Suzuki-Miyaura and Buchwald-Hartwig reactions for the synthesis of 2-aryl thiophenes, a component of several classes of functional organic electronic materials, and N-(4-nitrophenyl)-1,2-ethanediamine, respectively. This same nanocomposite was recycled up to three runs without loss in catalytic activity. A tentative test envisaging a one-pot borylation-Suzuki-Miyaura strategy indicated that the Miyaura borylation was conceivably affected by the coexisting malachite and spertiniite phases in the nanocomposite. However, control experiments in the presence of Cu(OH)2, Al(OH)3 and malachite indicate a lack of catalytic activity for these phases in Suzuki-Miyaura reactions. Thus, the catalytic activity is mostly attributed to the nanocomposite Cu–Al LDHs containing CDs. The enhancement in catalytic activity is suggested to occur as a result of deprotonation/adsorption of phenylboronic acid, transmetallation facilitated by a relatively high surface hydroxyl sites, improved substrate complexation by β-CDs and potential soluble Cu(II) active species from the layered matrix.

Effect of Er3+ ions on the structural, optical and Judd-Ofelt (JO) intensity parameters of (Bi2O3-BaTiO3) glass system and their application as fiber-amplifier

Barium titanate-based bismuthate glasses doped with Er3+ ions have been fabricated by employing the conventional melt quench technique. Various characterization studies have been performed on the samples for their physical, structural and optical analysis such as the density and molar volume measurements, X-Ray diffraction (XRD), Fourier transform infrared (FTIR), Raman, and UV–Vis spectroscopies. The amorphous nature of the prepared glass samples has been confirmed by the broad humps observed in the X-Ray diffractograms. The FTIR spectra confirmed an increment in the non-bridging oxygen atoms (NBOs) and also the transformation of [BiO6] units to [BiO3] pyramidal units in the structural network of the glass matrix. Raman spectra in the high-frequency region have also been recorded which provided information related to the structural changes in the glass system upon the building of Er-O linkages. Absorption spectra of UV–Vis spectroscopy depicted six transition states such as 4F7/2, 2H11/2, 4S3/2, 4F9/2, 4I11/2, and 4I13/2. The spectroscopic and optical parameters such as energy band gap, optical conductivity, penetration depth, Judd-Ofelt (JO) parameters, refractive index, dielectric constant, Urbach energy, and transmission coefficient for the glasses have been determined, among others. The nephelauxetic ratio (β) and bonding parameters (δ) obtained from transitions of rare-earth ions have revealed the ionic character of the glasses. The calculated values of indirect and direct energy bandgap (Eg) of the prepared samples have been found to decrease from 2.04 to 1.93 and 2.67 to 2.45 resp. on increasing Er3+ ions. Judd-Ofelt (JO) parameters follow the order given by Ω2> Ω6> Ω4 and have been consistent with the literature. A decrement in the values of Ω2 from 3.761 to 2.699, confirmed the lowest asymmetry in the crystal field of rare-earth ions of glass system. The obtained values of refractive index, Urbach energy, dielectric constant, electronic & ionic polarizability and the metallization criterion suggest that the presently studied glass samples are amorphous semiconducting, optically non-linear and are suitable for the applications in erbium-doped fiber-amplifier (EDFA), lasers and optoelectronic devices.

Antimicrobial Efficacy of Green Synthesized Nanosilver with Entrapped Cinnamaldehyde against Multi-Drug-Resistant Enteroaggregative Escherichia coli in Galleria mellonella.

The global emergence of antimicrobial resistance (AMR) needs no emphasis. In this study, the in vitro stability, safety, and antimicrobial efficacy of nanosilver-entrapped cinnamaldehyde (AgC) against multi-drug-resistant (MDR) strains of enteroaggregative Escherichia coli (EAEC) were investigated. Further, the in vivo antibacterial efficacy of AgC against MDR-EAEC was also assessed in Galleria mellonella larval model. In brief, UV-Vis and Fourier transform infrared (FTIR) spectroscopy confirmed effective entrapment of cinnamaldehyde with nanosilver, and the loading efficiency was estimated to be 29.50 ± 0.56%. The AgC was of crystalline form as determined by the X-ray diffractogram with a mono-dispersed spherical morphology of 9.243 ± 1.83 nm in electron microscopy. AgC exhibited a minimum inhibitory concentration (MIC) of 0.008–0.016 mg/mL and a minimum bactericidal concentration (MBC) of 0.008–0.032 mg/mL against MDR- EAEC strains. Furthermore, AgC was stable (high-end temperatures, proteases, cationic salts, pH, and host sera) and tested safe for sheep erythrocytes as well as secondary cell lines (RAW 264.7 and HEp-2) with no negative effects on the commensal gut lactobacilli. in vitro, time-kill assays revealed that MBC levels of AgC could eliminate MDR-EAEC infection in 120 min. In G. mellonella larvae, AgC (MBC values) increased survival, decreased MDR-EAEC counts (p < 0.001), had an enhanced immunomodulatory effect, and was tested safe to the host. These findings infer that entrapment enhanced the efficacy of cinnamaldehyde and AgNPs, overcoming their limitations when used individually, indicating AgC as a promising alternative antimicrobial candidate. However, further investigation in appropriate animal models is required to declare its application against MDR pathogens.

Formation of polymorphs and pores in small nanocrystalline iron oxide particles

A novel chemical vapor synthesis reactor design is used to control the pore-particle mesostructure and investigate the pore formation mechanism through the variation of residence time in oxygen. This enables the exploitation of the Kirkendall effect at the nanoscale to generate ultrasmall pores in small nanocrystalline iron oxide particles. Detailed structural characterization and quantitative data analysis of complementary high resolution transmission electron microscopy images, X-ray diffractograms, nitrogen sorption isotherms and X-ray absorption spectra provide a consistent comprehensive picture of the hollow nanoparticles from the local to the microstructure. The pore formation mechanism seems to play a key role for β-Fe2O3 polymorph formation.

Effect of Sn concentration on the structural, morphological and thermoelectric transport properties of zinc Stannates thin films

This study aimed to set suitable Tin dopant concentration in ZnO based thin films to get optimal structural, morphological and thermoelectric properties. The samples under investigation were prepared by thermal evaporation technique using stoichiometric ratios of Zn and Sn powders. X-ray diffractograms showed that all grown samples are fully c-axis oriented but increasing Sn concentration caused a blue shift in XRD peak position. Raman spectrum of ZTO nanoparticles has confirmed the perfect wurtzite structure having an intense E2 mode. It was further showed that with increasing crystallite size, the frequency of E2 (highest peak) phonon mode decreases whereas its line width increases. The Seebeck coefficient has maximum value (800 μV/K) for un-doped sample while the value of electrical conductivity (5.2 S/cm) has maximum value for sample having Sn concentration 4%. This behavior of thermoelectric properties can be understood by the fact that Sn doping concentration increases the free carrier concentration in the host crystal of ZnO which resulted in the reduction of Seebeck coefficient and enhancement of electrical conductivity. This argument was further highlighted by the SEM measurements.

Solid Dispersion of Dolutegravir: Formulation Development, Characterization, and Pharmacokinetic Assessment

A recently authorized antiviral drug called dolutegravir has solubility problems and could be a Biopharmaceutical Classification System (BCS) class II candidate. The current study aimed to improve dolutegravir’s solubility and efficiency by employing the solid dispersion method. Different ratios of hydrophilic polymeric carriers, including polyethylene glycol (PEG) 6000, polyvinyl pyrrolidone (PVP) (30K), and hydroxypropyl methylcellulose (HPMC), were used. Dolutegravir (DTG) and soluplus were produced as a solid dispersion at 1:5 ratio using the solvent evaporation method. A variety of techniques were utilized to describe the solid state, including powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and fourier transform infrared spectroscopy (FTIR). Produced solid dispersion did not reveal any physicochemical interactions between the DTG and soluplus, but the X-ray diffractogram clearly showed that the drug’s crystalline state had transformed to an amorphous state. DTG was released quickly from solid dispersion (92%) compared to pure drug (10.12%), physical mixture (22.06%), and commercially available DTG (62.90%). The formed solid dispersion’s drug release kinetics was in line with the Higuchi Model. Finally, the rapid drug release from the solid dispersion formulation showed higher Cmax (15.25 ± 0.40 μg/mL) compared to the physical mixture (5.11 ± 0.20 μg/mL) and pure drug (4.91 ± 0.73 μg/mL). DTG’s enhanced bioavailability in experimental wistar rats (AUC: 147.99 ± 23.86 μg/h/mL) further supported this when compared to the AUC of animals administered with physical mixture (52.35 ± 4.32 μg/h/mL) and pure drug (43.32 ± 3.13 μg/h/mL). Thus, it could be inferred that by employing the solid dispersion delivery system and the hydrophilic carrier, soluplus, the bioavailability and dissolution profile of DTG could both be improved, which could be expected to improve the drug’s effectiveness in treating Human immunodeficiency virus/Acquired immunodeficiency syndrome (HIV/AIDS).

Study on characteristic strength of Geopolymer Aggregate Concrete

The stone quarrying activities to meet the demand for infrastructure development, which in turn impacts on the soil and water resources, affect the hydro-geological and hydrological regimes. Due to the increase in urbanisation and industrialization, a large quantity of industrial waste is produced in developing as well as developed countries, and the unscientific disposal of this industrial waste is creating huge environmental problems. In this study, an attempt is made to incorporate both the problems and to find an alternative for natural aggregates with industrial by-products fly ash and GGBS for manufacturing artificial aggregates by adopting the geo-polymerization technique. The characteristic strength, flexural strength, and split tensile strength of geopolymer aggregate (GPA) concrete for varying percentage replacements, such as 25%, 50%, 75%, and 100% for natural coarse aggregates, have been studied and compared with normal concrete. Based on the test results, geopolymer aggregates could be considered as an alternate source for natural aggregates. The 28-day compressive test results showed that for 75% and 100% replacement, GPA3 concrete has been conducted with XRD analysis and SEM analysis on the microstructure of geopolymer aggregates manufactured with varying mix ratios of source materials and curing periods of X-Ray diffractograms and patterns. exhibit the formation of N-A-S-H and C-A-S-H compounds, which indicates the geopolymer formed has similar chemical compositions as natural rocks.

In vitro evaluation of bioactivity of SiO2–CaO and SiO2–CaO–P2O5 glass nanoparticles activated with Tm3+/Yb3+ ions

In this study, the SiO2–CaO (SC) and SiO2–CaO–P2O5 (SCP) glass powders doped with 0.3 mol% of Tm3+ and 4 mol% of Yb3+ ions were prepared by the sol–gel method. The samples were immersed for four weeks in a simulated physiological environment (Dulbecco's phosphate-buffered saline, DPBS) to investigate the bioactivity of the glasses. Their structure, morphology, and spectroscopic properties were investigated in the function of immersion time. X-ray diffractograms and infrared spectra showed that after incubation in DPBS, the hydroxyapatite starts to build up after 1–3 days. The energy dispersive X-ray spectroscopy analysis indicated the dynamics of ion exchange resulting from the biomineralization process in the glasses. Moreover, the upconversion emission spectra of Tm3+ were measured for all samples under 980 nm excitation wavelength in resonance with the 2F7/2 → 2F5/2 absorption of Yb3+. It was observed that the upconversion luminescence continuously decreased and the decay times shorten slightly after the immersion in the buffer. In vitro cytotoxicity assays revealed that the SC glass was biocompatible for all tested cell lines (human chondrocytes, osteoblasts, and fibrosarcoma). However, the SCP powder showed an inhibitory effect on human chondrocyte and fibrosarcoma cells in small concentrations and fibrosarcoma cells in high concentrations.

Sustainable Production of Novel Oleogels Valorizing Microbial Oil Rich in Carotenoids Derived from Spent Coffee Grounds.

Sustainable food systems that employ renewable resources without competition with the food chain are drivers for the bioeconomy era. This study reports the valorization of microwave-pretreated spent coffee grounds (SCGs) to produce oleogels rich in bioactive compounds. Microbial oil rich in carotenoids (MOC) was produced under batch fermentation of Rhodosporidium toruloides using SCG enzymatic hydrolysates. Candelilla wax (CLW) could structure MOC and sunflower oil at a 3.3-fold lower concentration than that of carnauba wax (CBW). MOC-based oleogels with 10% CBW and 3% CLW showed an elastic-dominant and gel-like structure (tan δ ≪ 1), providing gelation and oil binding capacity (>95%). Dendritic structures of CBW-based oleogels and evenly distributed rod-like crystals of CLW-based ones were observed via polarized light microscopy. MOC-based oleogels exhibited similar Fourier-transform infrared spectroscopy spectra. X-ray diffractograms of oleogels were distinguished by the oil type that presented β'-type polymorphism. MOC-based oleogels could be applied in confectionary products and spreads as substitutes for trans fatty acids, reformulating fat-containing food products.

Supercritical CO2-Induced Evolution of Alkali-Activated Slag Cements.

The phase changes in alkali-activated slag samples when exposed to supercritical carbonation were evaluated. Ground granulated blast furnace slag was activated with five different activators. The NaOH, Na2SiO3, CaO, Na2SO4, and MgO were used as activators. C-S-H is identified as the main reaction product in all samples along with other minor reaction products. The X-ray diffractograms showed the complete decalcification of C-S-H and the formation of CaCO3 polymorphs such as calcite, aragonite, and vaterite. The thermal decomposition of carbonated samples indicates a broader range of CO2 decomposition. Formation of highly cross-linked aluminosilicate gel and a reduction in unreacted slag content upon carbonation is observed through 29Si and 27Al NMR spectroscopy. The observations indicate complete decalcification of C-S-H with formation of highly cross-linked aluminosilicates upon sCO2 carbonation. A 20–30% CO2 consumption per reacted slag under supercritical conditions is observed.

Theoretical and experimental approaches for the determination of functional properties of MgSnN2 thin films

MgSnN2 thin films were deposited by reactive magnetron co-sputtering on fused silica and silicon substrates. The properties of the films were determined as a function of the deposition temperature. Although the films exhibited a strong preferred orientation along the [002] direction, cumulative X-ray diffractograms at various χ angles evidenced that the deposited films crystallized in a wurtzite-like structure. Regardless of the substrate temperature during deposition, MgSnN2 films had a columnar microstructure. Mössbauer spectrometry and X-ray photoemission spectroscopy were used to extract the chemical environment of magnesium and tin atoms and to identify their oxidation states. Electrical properties were deduced from Hall effect measurements. An increase of the electron mobility was noticed at high deposition temperature. The optical band gap of MgSnN2 films increased from approx. 2.28 to 2.43 eV in the 300–500 °C range. The experimental optical properties of MgSnN2 films were compared to those obtained by ab initio calculations.