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The aim of this work is to assess the crystalline structure modification of an SLM Co-Cr-W dental alloy, veneered with two different ceramics, by means of X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy, coupled with energy-dispersive spectroscopy (SEM-EDS). Ten identical plates were fabricated using SLM and were subsequently subjected to ceramic veneering. Following the repeated firing of the ceramic layers, carried out at temperatures exceeding 900 °C, new crystalline phases and variations in the crystallite sizes in the SLM Co-Cr-W dental alloy used for the substructure were detected via XRD. The two veneering ceramics showed significant differences in their behavior, beginning with the first firing, accompanied by structural changes. AFM micrographs and histograms of the surface heights over the whole scanned area of the samples showed that the surface of the Co-Cr-W dental alloy is strongly affected by the repeated firings necessitated by the ceramic firing process, a finding in accordance with the XRD results. The SEM investigation revealed that the different firing parameters had an impact on the alloy, the ceramic microstructure, and the surface quality. The differences in the chemical composition of the ceramics, highlighted by EDS, are reflected in their behavior. The crystalline alloy structure is influenced by the repeated firings of the ceramic layers.

Un-doped (uZO) and silver-doped zinc oxide (SZO) films were prepared by oblique incidence sputtering deposition under different process parameters. The crystalline structure, chemical composition, and surface morphology were correlated with the optical properties, as well as with the wettability of the films. In the case of uZO films, the orientation, inclination, and morphology of the columnar structure determined the wettability of the layer, moving from a hydrophilic- to hydrophobic-like character. In the case of SZO films, although almost all of them displayed hydrophobic behavior, the hydrophobic character increased with the Ag content. The most hydrophobic surface was obtained when the Ag content in the layers was greater than 7 at.% and, in these cases, the structural results indicate that the layers were formed by a disordered mixture of Zn and Ag oxides., This research was funded by grant TED2021-129876B-I00 of the Ministerio de Ciencia, Innovación y Universidades (Spain).

Iron-based compounds with a ThMn12-type structure have the potential to bridge the gap between ferrites and high performance Nd2Fe14B magnets. From the point of view of possible applications, the main advantage is their composition, with about 10 wt.% less rare earth elements in comparison with the 2:14:1 phase. On the other hand, the main issue delaying the development of Fe-rich alloys with a ThMn12-type structure is their structural stability. Therefore, various synthesis methods and stabilizing elements have been proposed to stabilize the structure. In this work, the influence of increasing Nd substitution on the phase constitution of Zr0.4−xNdxCe0.6Fe10Si2 (0 ≤ x ≤ 0.3) alloys was analyzed. X-ray diffraction and 57Fe Mössbauer spectrometry were used as the main methods to derive the stability range and destabilization routes of the 1:12 structure. For the arc-melted samples, an increase in the lattice parameters of the ThMn12-type structure was observed with the simultaneous growth of bcc-(Fe,Si) content with increasing Nd substitution. After isothermal annealing, the ThMn12-type structure (and the coexisting bcc-(Fe,Si)) were stable over the whole composition range. While the formation of a 1:12 phase was totally suppressed in the as-cast state for x = 0.3, further heat treatment resulted in the growth of about 45% of the ThMn12-type phase. The results confirmed that the stability range of ThMn12-type structure in the Nd-containing alloys was well improved by other substitutions and the heat treatment, which in turn, is also needed to homogenize the ThMn12-type phase. After further characterization of the magnetic properties and optimization of microstructure, such hard/soft magnetic composites can show their potential by exploiting the exchange spring mechanism.

The alloys that crystallize in a tetragonal ThMn12-type (space group I4/mmm) structure and are based on Fe and rare earth elements are believed to have a potential to plug the performance gap between ferrite and Nd-based magnets. Nevertheless, the progress is hindered by their poor structural stability, compared with other phases competing during the synthesis process, e.g., Th2Zn17-type. In this work, the enthalpies of the formation (and other thermodynamic parameters) of various phases in (Zr, Nd, Ce)-Fe-Si systems were calculated, with paramount focus on the Fe-rich compositions. We compared and discussed the stability range and stabilization routes for amorphous phases, solid solutions, and intermetallics. The beneficial influence of Zr and Si on the crystallization of intermetallic compounds was confirmed, simultaneously being valid for other phases. Among all of the analyzed Fe-rich phases, the lowest values for enthalpy of the formation of the amorphous phase and solid solution were determined for ZrFe10Si2 (−17.5 and −18.2 kJ/mol, respectively). Moreover, substitution by elements with a large atomic radius is indicated as a method for the introduction of topological disorder, giving possibility for the synthesis of metastable phases (even amorphous) and the utilization of more sophisticated synthesis routes in the future.

TMB-5 nucleating agent (NA) treated by different solvents were used as the β-NA of iPP. The effects of temperature on the crystalline structure of different iPP/TMB-5, as well as the crystallization and melting behaviors were investigated. It was found that strong polar solvent treated TMB-5 (TMB-5DMSO and TMB-5DMF) could induce more β-crystal at high Tc = 140 °C than the other TMB-5 NAs, while the β-crystal inducing efficiency of untreated TMB-5 (TMB-5UT) and non-polar solvent treated TMB-5 (TMB-5LP) is seriously reduced at high Tc = 140 °C. TMB-5DMSO can induce a high and stable content of β-crystal with Kβ = 83–94% within Tc = 90–140 °C, and TMB-5ODCB can induce a high content of β-crystal with Kβ > 91.3% within Tc = 90–130 °C. TMB-5DMF is the most temperature-sensitive one, but can induce a high fraction of β-crystal with Kβ > 92% both at low Tc = 90 °C and high Tc = 140 °C. High temperature pre-crystallization at Tpc = 150 °C tremendously reduces the β-crystal inducing efficiency of all TMB-5 NAs. TMB-5UT and TMB-5LP exhibit higher nucleating efficiency than TMB-5DMSO, TMB-5DMF and TMB-5ODCB. During the non-isothermal crystallization process, TMB-5UT induced β-crystal possesses higher structural perfection and stability, while TMB-5LP is more likely to induce α-crystal with considerable quantity and stability. The structural perfection and stability of TMB-5 induced β-crystal can be enhanced with appropriate increasing of Tc.

The use of renewable monomers and green polymerization processes for preparing new synthetic polymers is a hot topic today. In this work we have obtained high molecular weight copolyesters derived from ¿-pentadecalactone (PDL), dimethyl succinate (DMS) and 1,4-cyclohexanedimethanol (1,4-CHDM) by a combination of ring opening polymerization (ROP) and two step melt polycondensation processes. The reaction has been carried in bulk under mild conditions (80–120 ¿C) and catalyzed by immobilized Candida artarctica lipase B (N435 biocatalyst). These reactions were followed by 1 H NMR and it was observed that although PDL reacted faster, at the end copolyesters displayed a random microstructure due to transesterification reactions taking place during polymerization. These copolyesters were thermally stable up to around 350 ¿C and semicrystalline for all compositions with melting temperatures decreasing with the increased content of the counterpart comonomer up to a pseudo-eutectic point located at 40 mol-% of PDL composition. The crystalline structure and transitions taken place by heating have been studied by WAXS and SAXS synchrotron X-ray diffraction. Copolyesters with elastomeric properties could be obtained at intermediate compositions. Peer Reviewed Objectius de Desenvolupament Sostenible::13 - Acció per al Clima Objectius de Desenvolupament Sostenible::3 - Salut i Benestar

Sepiolite clay is a natural filler particularly suitable to be used with polysaccharide matrices (e.g., in starch-based bio-nanocomposites), increasing their attractiveness for a wide range of applications, such as packaging. Herein, the effect of the processing (i.e., starch gelatinization, addition of glycerol as plasticizer, casting to obtain films) and of the sepiolite filler amount on the microstructure of starch-based nanocomposites was investigated by SS-NMR (solid-state nuclear magnetic resonance), XRD (X-ray diffraction) and FTIR (Fourier-transform infrared) spectroscopy. Morphology, transparency and thermal stability were then assessed by SEM (scanning electron microscope), TGA (thermogravimetric analysis) and UV–visible spectroscopy. It was demonstrated that the processing method allowed to disrupt the rigid lattice structure of semicrystalline starch and thus obtain amorphous flexible films, with high transparency and good thermal resistance. Moreover, the microstructure of the bio-nanocomposites was found to intrinsically depend on complex interactions among sepiolite, glycerol and starch chains, which are also supposed to affect the final properties of the starch–sepiolite composite materials.

Proteins’ functions are dependent on their three-dimensional (3D) structure. Under certain circumstances, proteins misfold and form aggregates, sometimes leading to amyloidosis. Islet amyloid polypeptide (IAPP) builds up amyloid in the pancreatic islet of patients with type 2 diabetes (T2D). We utilized the GAL4-UAS system to express human proIAPP (hproIAPP), human IAPP (hIAPP) and mouse IAPP (mIAPP) in the brain of Drosophila melanogaster. In transmission electron microscope (TEM), we observed an accumulation of non-fibrillar aggregates in fat body tissue surrounding the brain. TEM tomography used for ultrastructure analysis revealed a spherical shape and a 5-fold twinning structure composed of two crystal packings: the body centered tetragonal (BCT) structure and the triclinic structure. Our biological systems have developed the ability to assist in folding and removing non-functional proteins. We directed the expression of hproIAPP and hIAPP to the 16 ventral lateral neurons (LNvs) and monitored intracellular responses to protein aggregation. We observed that overexpression of hproIAPP and hIAPP significantly reduced the number of LNvs over time. Further studies showed that expression of hproIAPP and hIAPP did not trigger ER stress and apoptosis but resulted in an accumulation of ubiquitinated aggregates, autophagosomes, and lysosomes, indicative of activation of aggrephagy. Overexpression of hproIAPP/hIAPP in flies with the Gstd-ROS reporter results in ROS generation, which can contribute to cell death. Systemic amyloidosis is a rare condition where amyloid deposits occur in multiple organ systems. Deposits of wild type transthyretin (TTRwt) cause the most prevalent form of systemic amyloidosis, while TTR mutations can result in familial forms of the disease. The clinical profile in hereditary ATTR amyloidosis differs in the age of onset, tissue distribution, symptoms, disease penetrance, and prognosis. The Gal4-UAS system was applied to produce flies expressing human TTRwt and single mutant TTR. The Hand-C-Gal4 driver directs the TTR expression in the cardioblasts of the heart. We found the expression of TTRV30L, TTRV30M, TTRA109S, and TTRL111M had a significant impact on cardiac parameters. The Nrv2-Gal4 driver directs the TTR expression to the central and peripheral nerve cells. Expression of TTRV30L, TTRV30M, TTRL55P, and TTR L111M by Nrv2-Gal4 altered the activity or circadian rhythm in the fly. The results showed that different mutations give rise to different phenotypes. In summary, our Drosophila melanogaster models provide valuable insights into amyloidosis and allow for cellular and organ analysis.

Direct current (DC) and radio frequency (RF) magnetron sputtering methods were selected for conducting the deposition of structural materials, namely ceramic and metallic co-depositions. A total of six configurations were deposited: single thin layers of oxides (Cr2O3, SiO2) and co-deposition configurations (50:50 wt.%) as structural materials (W, Be)—(Cr2O3, SiO2), all deposited on 304L stainless steel (SS). A comprehensive evaluation such as surface topology, thermal desorption outgassing, and structural/chemical state was performed. Moreover, mechanical characterization evaluating properties such as adherence, nano indentation hardness, indentation modulus, and deformation relative to yielding, was performed. Experimental results show that, contrary to SiO2 matrix, the composite layers of Cr2O3 with Be and W exhibit surface smoothing with mitigation of artifacts, thus presenting a uniform and compact state with the best microstructure. These results are relevant in order to develop future dense coatings to be used in the fusion domain.

International audience; It is assumed that genetic diseases affecting the metabolism of cysteine and the kidney function lead to two different kinds of pathologies, namely cystinuria and cystinosis whereby generate L-cystine crystals. Recently, the presence of L-cysteine crystal has been underlined in the case of cystinosis. Interestingly, it can be strikingly seen that cystine ([-S-CH2-CH-(NH2)-COOH]2) consists of two cysteine (C3H7NO2S) molecules connected by a disulfide (S-S) bond. Therefore, the study of cystine and cysteine is important for providing a better understanding of cystinuria and cystinosis. In this paper, we elucidate the discrepancy between L-cystine and L-cysteine by investigating the theoretical and experimental infrared spectra (IR), X-ray diffraction (XRD) as well as Raman spectra aiming to obtain a better characterization of abnormal deposits related to these two genetic pathologies.

Silk fibroin (SF) is a natural protein polymer and promising biomaterial. Chemical modifications have attracted growing interest in expanding SF applications. However, the majority of amino acid residues in SF are non-reactive and most of the reactive ones are in the crystalline region. Herein, a modification was conducted to investigate the possibility of direct modification on the surface of natural SF by a reagent with a mild reactivity, the type and quantity of the residues involved in the reactions, and the structural changes upon modification. Infrared spectrum, 1H NMR, titration and amino acid analyses, X-ray diffraction, and hemolysis test were used to analyze the materials. The results showed that sulfonic acid groups were grafted onto SF and the reaction occurred mainly at serine residues through hydroxyl groups. In total, 0.0958 mmol/g of residues participated in the modification with a modification efficiency of 7.6%. Moreover, the crystallinity and the content of β-sheet structure in SF increased upon modification. The modified material had good blood-compatibility. In conclusion, surface modification on native SF through serine residues was practicable and had the advantage of increased β-sheet structure. This will provide an alternative way for the modification of fibroin for the desired application in the biomedical field.

Dispersed silver nanoparticles (NPs) are synthesized on a silicone oil substrate under varied substrate temperature T by thermal vaporization method. Scanning electron microscopic investigation demonstrates that the mean size of the NPs are around 7.8 nm with a standard deviation of 1.0 nm. The NPs are transferred to a strontium titanate (STO) crystal as co-catalyst for water splitting efficiency test. The photoelectrochmical (PEC) measurement reveals the photocatalytic activity of NP co-catalyst sensitively relies on T during deposition process: the relative current density jr increases from 4.8 μA/cm2 to 25.4 μA/cm2 as T goes up from 253 K to 333 K. However, a slight decrease of jr from 25.4 μA/cm2 to 22.8 μA/cm2 is found as T further increases to 353 K. The dependent behavior of jr on T is explained in term of a competition mechanism between microstructure evolution and growth model of the NPs under different T: for T ranging from 253 K to 333 K, the effect of a higher crystalline structure for NPs fabricated under higher T improves the electron transfer rate from STO to NPs is dominant. As T increases to 353 K, the overlapping of NPs become a factor for photocatalytic activity of NP/STO system: the diffusion distance of electrons becomes larger and the apparent contact area between NPs and STO is reduced which in turn reduce the photocatalytic activity of NP/STO. The experimental method to synthesize NPs in this report may open up a way to further apply fine NPs in enhancing photocatalytic water splitting efficiency.

Late-stage nitrogen (N) fertilization is an important crop management for improving rice production and also affects the quality of rice, whereas information on the influence of late N on structural and functional properties of indica rice starch is lacking. In this study, effects of various N rates (0, 60, and 120 kg ha−1 referred to as N0, N60 and N120, respectively) on structural and functional properties of grain starches from two rice cultivars (OM052 and Chaoyou1000) were investigated. Comparison of different N treatments showed that late N application exhibited strong influence on starch properties, and the sensitivity to N application varied with rice genotypes. Compared to non N rate, higher input of N (N60 for OM052, and N120 for Chaoyou1000) significantly reduced apparent amylose content (AAC), relative crystallinity (RC), gelatinization enthalpy, swelling power, solubility and degree of hydrolysis, but significantly increased the proportion of short chains with degree of polymerization 6–12 in amylopectin and gelatinization onset temperature. Further comparison and principal component analyses revealed that the variations in the starch functional properties were due mainly to the changes in RC. The solubility was positively associated with AAC. The present results can provide important information for understanding the environmental regulation of starch biosynthesis in rice grain.

Ti-based alloys are an important class of materials suitable especially for medical applications, but they are also used in the industrial sector. Due to their low tribological properties it is necessary to find optimal technologies and alloying elements in order to develop new alloys with improved properties. In this paper, a study on the influence of sintering treatments on the final properties of a titanium alloy is presented. The alloy of interest was obtained using the powders in following weight ratio: 80% wt Ti, 8% wt Mn, 3% wt Sn, 6% wt Aluminix123, 2% wt Zr and 1% wt graphite. Two sintering methods were used, namely two-step sintering (TSS) and multiple-step sintering (MSS), as alternatives to conventional sintering which uses a single sintering dwell time. Evolution of sample morphology, composition and crystalline structure with sintering method was evidenced. The lower values for the friction coefficient and for the wear rate was attained in the case of the sample obtained by TSS.

Copper (Cu) and nickel (Ni) nanoparticles have been grown simultaneously on glass and silicon substrates by RF sputtering method to form three Cu/Ni nanocomposites at different deposition times. The existence of Cu and Ni peaks in the X-ray diffraction (XRD) profiles confirms the crystalline structure of samples with Cu and Ni atomic content which have also been characterized by Rutherford backscattering (RBS) method. Moreover, the structural and morphological properties of the prepared nanocomposites have been compared with respect to their morphologies by means of atomic force microscopy (AFM) analysis. In order to compare the surface roughness over different spatial frequency ranges and evaluate surface quality, power spectral density (PSD) of each sample has been extracted from AFM data and also, the experimental and theoretical results have been compared. The fractal nature of these nanocomposites has been finally discussed.

Magnetic shape memory Heusler alloys, such as NiCoMnAl, are considered as promising candidates for magnetocaloric cooling applications. Grown in thin film systems of adjacent layers with austenite and martensite crystal structures of almost equal thicknesses, a long-range ordering phenomenon in the shape of a 3D checkerboard pattern occurs in NiCoMnAl samples. The crystallographic origin of the pattern is proven by transmission electron microscopy (TEM) techniques. The darker fields of the arrangement consist of martensite nuclei superposed with austenite, while the purely austenite regions appear bright in TEM cross sections. The nucleation process is presumably triggered by inhomogeneous local elastic stray fields of primary martensitic nuclei in the austenite matrix and limited by the thicknesses of the martensite and austenite thin films.

Magnetic shape memory Heusler alloys, such as NiCoMnAl, are considered as promising candidates for magnetocaloric cooling applications. Grown in thin film systems of adjacent layers with austenite and martensite crystal structures of almost equal thicknesses, a long-range ordering phenomenon in the shape of a 3D checkerboard pattern occurs in NiCoMnAl samples. The crystallographic origin of the pattern is proven by transmission electron microscopy (TEM) techniques. The darker fields of the arrangement consist of martensite nuclei superposed with austenite, while the purely austenite regions appear bright in TEM cross sections. The nucleation process is presumably triggered by inhomogeneous local elastic stray fields of primary martensitic nuclei in the austenite matrix and limited by the thicknesses of the martensite and austenite thin films.

This dissertation is dedicated to the growth and investigation of La1-xSrx(Mn1-yCoy)zO3 (x = 0.20 ± 0.02; z = 1.15) (LSMCO) films. LSMCO films were grown by the pulsed-injection metalorganic chemical vapor deposition method (PI-MOCVD) at a deposition temperature of 750 oC. The structural, electrical, and magnetic properties were measured for thin LSMCO films exhibiting manganese nonstoichiometry and difference in cobalt content ranging from 0 to 0.17. LSMCO films grown on LaAlO3 substrates were epitaxial, while nanostructured films formed on sapphire-R and Al2O3 substrates. Structural studies have revealed that epitaxial LSMCO films are characterized by tensile and compressive stresses depending on the cobalt content. Meanwhile, only tensile stresses were found in nanostructured LSMCO films. The performed electrical measurements showed that the phase transition temperature determined for epitaxial and nanostructured LSMCO films decreases with increasing cobalt content in the film. The influence of cobalt on the magnetoresistive properties of both epitaxial and nanostructured LSMCO films has also been evaluated, as it is relevant for the application of magnetic sensor design. The results of structural, electrical and magnetic studies showed that the chemical composition determines the properties of LSMCO films, so the properties of LSMO (La1-xSrxMnzO3) and LSMCO were compared. Structural, electrical, and magnetic studies for the LSMO and LSMCO films revealed that changes in epitaxial films were Mn-dependent, whereas changes in nanostructured films were related to cobalt content. A hybrid prototype sensor composed of a three-layered graphene and LSMCO film was also developed during this work to measure the magnetic field at room temperature over a wide magnetic field range (0.1–20 T).

High entropy alloys (HEAs) of the type CrCuFeNiTi-Alx were processed through mechanical alloying. The aluminum concentration was varied in the alloy, to determine its effect on the HEAs’ microstructure, phase formation, and chemical behavior. X-ray diffraction studies performed on the pressureless sintered samples revealed the presence of structures composed of face centered cubic (FCC) and body centered cubic (BCC) solid-solution phases. Since the valences of the elements that form the alloy are different, a nearly stoichiometric compound was obtained, increasing the final entropy of the alloy. The aluminum was partly responsible for this situation, which also favored transforming part of the FCC phase into BCC phase on the sintered bodies. X-ray diffraction also indicated the formation of different compounds with the alloy’s metals. Bulk samples exhibited microstructures with different phases. The presence of these phases and the results of the chemical analyses revealed the formation of alloying elements that, in turn, formed a solid solution and, consequently, had a high entropy. From the corrosion tests, it could be concluded that the samples with a lower aluminum content were the most resistant to corrosion.

In this work, the In2O3 thin films have been fabricated using a spin coating technique; this technique was prepared in our laboratory. The effect of the layer times (3, 5, 7 and 9 times) on optical and structural properties was investigated. In2O3 thin films were fabricated by dissolving 0.2 M of the indium chloride dehydrate InCl3.2H2O in the absolute H2O. The In2O3 thin films were crystallized at a temperature of 600 °C with pending time of 1 hour. The optical property shows that the prepared In2O3 thin films for 3 and 5 times have a transmission of about 85 %. The maximum bandgap energy was 3.69 eV for 5 times and the lowest Urbach energy was 0.47 eV for 9 times. From XDR all fabricated In2O3 thin films having one diffraction crystal plan is (222) peak intensity, this attribution have good crystalline structure with minimum crystallite size of the (222) plan is 59.69 nm. The prepared In2O3 thin films can be used in photovoltaic applications due to the existing phase and higher transmission.

Undoped and Gd-doped BaTiO3 samples, with the chemical formula BaGdxTi1-xO3-x/2���x/2, x = 0.00; 0.01; 0.02; 0.03; 0.04 and 0.05, were synthesized using the sol gel process. During the procedure of preparation of these samples acetic acid and distilled water were used as solvents. All the powders corresponding to the two series of undoped and doped samples were calcined in air at different temperatures and their crystalline phase was checked using results from XRD and Raman analyses. Acetic acid was shown to provoke the formation of the stable pseudo cubic structure for the two series of samples at relatively low temperature of crystallization, while with the use of distilled water only (without acetic acid) the tetragonal phase prevailed. In this study, the effect of acetic acid is discussed and the latter seems to play a more or less important role in the formation of the structure of BT material., Moroccan Journal of Chemistry, Vol. 9, No 4 (2021): in progress

Next-generation high resolution brightfield microscopy, x-radiography, and microcomputed tomography (microCT) analyses indicate that coral skeleton high density band (HDB) and low density band (LDB) stratigraphic sequences record dynamic changes in coral growth history. HDB-LDB sequences were studied within three small heads of Orbicella annularis, an ecological keystone species in the Caribbean Sea, collected from the leeward fringing reefs on Curaçao. Results indicate that HDB layers are formed by the thickening of exothecal and endothecal dissepiments, costae, and theca located at the margin and external to individual skeletal cups (corallites). Conversely, septa and columellas located inside individual corallites do not change in thickness. HDB-LDB stratigraphic sequences were laterally traced from the center to the margins of individual coral heads, demonstrating that shifts took place in the trajectory of coral skeleton growth. Normal HDB layers in the center of individual coral heads are formed at the same time (age-equivalent) as surfaces of erosion and no skeleton growth (hiatuses) on the margins of the heads. These hiatus surfaces within HDB-LDB stratal geometries indicate that multiple marine ecological and environmental processes affect the orientation, size, shape, and geometry of coral skeletons during coral growth history. The presence of these hiatus surfaces in other large coral heads would strongly impact sclerochronology and the interpretation of multiple environmental factors including sea surface temperature (SST).

Zirconium dioxide (ZrO2) is one of the ceramic materials with high potential in many areas of modern technologies. ZrO2 doped with 8 wt.% (~4.5 mol%) Y2O3 is a commercial powder used for obtaining stabilized zirconia materials (8 wt.% YSZ) with high temperature resistance and good ionic conductivity. During recent years it was reported the co-doping with multiple rare earth elements has a significant influence on the thermal, mechanical and ionic conductivity of zirconia, due complex grain size segregation and enhanced oxygen vacancies mobility. Different methods have been proposed to synthesize these materials. Here, we present the hydrothermal synthesis of 8 wt.% (~4.5 mol%) YSZ co-doped with 4, 6 and 8 wt.% La2O3, Nd2O3, Sm2O3 and Gd2O3 respectively. The crystalline phases formed during their thermal treatment in a large temperature range were analyzed by X-ray diffraction. The evolution of phase composition vs. thermal treatment temperatures shows as a major trend the formation at temperatures >1000 °C of a cubic solid solutions enriched in the rare earth oxide used for co-doping as major phase. The first results on the thermal conductivities and impedance measurements on sintered pellets obtained from powders co-doped with 8 wt.% Y and 6% Ln (Ln = La, Nd, Sm and Gd) and the corresponding activation energies are presented and discussed. The lowest thermal conductivity was obtained for La co-doped 8 wt.% YSZ while the lowest activation energy for ionic conduction for Gd co-doped 8 wt.% YSZ materials.

Compact and defect-free high melting point oxide strengthened metallic matrix configurations are promising to resolve the hydrogen permeation and brittleness issues relevant to the fusion research community. Previous studies on oxide addition to metallic matrix demonstrated a mitigation in brittleness behavior, while deposition techniques and material configurations are still to be investigated. Thus, here, we report the structural, morphological, and mechanical characterization of metal-oxides thin layers co-deposited by radio frequency (RF)and direct current (DC) magnetron sputtering. A total of six configurations were deposited such as single thin layers of oxides (Al2O3, Er2O3) and co-deposition configurations as metal-oxides (W, Be)—(Al2O3, Er2O3). The study of films roughness by atomic force microscopy (AFM) method show that for Al2O3 metallic-oxides is increased to an extent that could favor gaseous trapping, while co-depositions with Be seem to promote an increased roughness and defects formation probability compared to W co-depositions. Lower elastic modulus on metal-oxide co-depositions was observed, while the indentation hardness increased for Be and decreased for W matrix configurations. These outputs are highly relevant for choosing the proper compact and trap-free configuration that could be categorized as a permeation barrier for hydrogen and furtherly studied in laborious permeation yield campaigns.

Zirconium dioxide (ZrO2) is one of the ceramic materials with high potential in many areas of modern technologies. ZrO2 doped with 8 wt.% (~4.5 mol%) Y2O3 is a commercial powder used for obtaining stabilized zirconia materials (8 wt.% YSZ) with high temperature resistance and good ionic conductivity. During recent years it was reported the co-doping with multiple rare earth elements has a significant influence on the thermal, mechanical and ionic conductivity of zirconia, due complex grain size segregation and enhanced oxygen vacancies mobility. Different methods have been proposed to synthesize these materials. Here, we present the hydrothermal synthesis of 8 wt.% (~4.5 mol%) YSZ co-doped with 4, 6 and 8 wt.% La2O3, Nd2O3, Sm2O3 and Gd2O3 respectively. The crystalline phases formed during their thermal treatment in a large temperature range were analyzed by X-ray diffraction. The evolution of phase composition vs. thermal treatment temperatures shows as a major trend the formation at temperatures >1000 °C of a cubic solid solutions enriched in the rare earth oxide used for co-doping as major phase. The first results on the thermal conductivities and impedance measurements on sintered pellets obtained from powders co-doped with 8 wt.% Y and 6% Ln (Ln = La, Nd, Sm and Gd) and the corresponding activation energies are presented and discussed. The lowest thermal conductivity was obtained for La co-doped 8 wt.% YSZ while the lowest activation energy for ionic conduction for Gd co-doped 8 wt.% YSZ materials.

Väitekirja elektrooniline versioon ei sisalda publikatsioone, Käesoleval ajal on suur vajadus funktsionaalsete materjalide järele, mis võiksid olla aluseks uute energiaefektiivsete seadmete ja mehhanismide arendamisel, millel on lai rakendusvaldkond ja võime funktsioneerida erinevates maa- ja kosmosetingimustes. Nagu esimesed tulemused on näidanud, on haruldaste muldmetallide oksühüdriididel mitmeid kasulikke funktsionaalseid omadusi, mida saab otseselt kasutada kaasaegsetes tehnoloogilistes lahendustes, eelkõige kõrgefektiivsete optiliste ja elektromehaaniliste seadmete arendamisel. Haruldaste muldmetallide oksühüdriidide keemiline projekteerimine algas rohkem kui 10 aastat tagasi, kui avastati, et hapniku lisamine hüdriidi struktuuri mitte ainult ei korralda ümber stöhhiomeetriat tänu vesiniku ja hapniku positsioonide paindlikule stabiliseerimisele kristallvõrega, vaid laiendab ka oluliselt modifitseeritud metallihüdriidide süsteemi omaduste kompleksi. See on avanud mitmesuguseid võimalusi parandada paljusid metallhüdriidide põhiomadusi ja suurendada nende funktsionaalsust, võimaldades seega teadlastel paindlikult modifitseerida ja muuta nende optilisi, mehaanilisi ja elektroonilisi omadusi. Teaduslikust ja tehnilisest seisukohast on kõige olulisem probleem välja selgitada, millist funktsionaalset rolli mängib hapniku keemiline lisamine tahkete oksühüdriidide omadustes. Seega oli käesoleva doktoritöö peamine eesmärk laiendada oluliselt meie teadmisi hapniku käitumisest haruldaste muldmetallide hüdriidides. Kasutades kaasaegseid matemaatika, teoreetilise füüsika ja kristallokeemia meetodeid ning mahukaid numbrilisi arvutusi superarvutis, uurisime haruldaste muldmetallide oksühüdriidide süsteemide kõige tõenäolisemaid struktuuri- ja koostise konfiguratsioone. See võimaldas meil ennustada suure hulga erinevate kristallstruktuuride ja hapniku/vesiniku vahekordadega ühendite teket ning konstrueerida ternaarne faasidiagramm Y- H-O muutujate puhul. Oleme kirjeldanud hapniku võtmerolli uute materjalide moodustamisel, mis mõjutab kristalliseerumist stabiilsesse oksühüdriidstruktuuri. Kõigist kolmekomponentsetest oksühüdriididest leidsime, et mõned oksühüdriidid on võimalik stabiliseerida polaarsetes mittetsentrosümmeetrilistes faasides, millel on silmapaistvad elastsed, piesoelektrilised ja elektromehaanilised omadused. Üks neist faasidest kuulub spetsiifilisele tetragonaalsele struktuurile, mille võrestiku konfiguratsioonil on unikaalne kiraalstruktuuriline ülesehitus, mis hõlmab kõiki elementaarraku katioone ja anioone. Arvutatud elektrooniliste ja optiliste omaduste põhjal pakkusime välja ka kaks erinevat optiliste katete prototüüpi, milles oksühüdriidi õhukesed kiled mängivad võtmerolli: i) madala emissiooniga katte mudel ja ii) valgust absorbeeriva mittepeegeldava katte mudel. Meie uurimistöö tulemused on oluliselt täiendanud haruldaste muldmetallide oksühüdriidide materjaliomadusi käsitlevat teadmistebaasi. Nad on tuvastanud nende materjalide elektrooniliste, elastsete, elektriliste ja optiliste omaduste mikroskoopilise olemuse detailid. See võimaldas meil mõista, kuidas nende omadused ja funktsionaalsed karakteristikud võivad olla tingitud erinevatest keemilistest ja füüsikalistest teguritest. Lisaks sellele oleme pakkunud välja võimalikud stsenaariumid perspektiivsete funktsionaalsete omadustega oksühüdriidmaterjalide prognoosimiseks ja projekteerimiseks, mida saab seejärel kasutada kaasaegsete optiliste ja elektromehaaniliste seadmete arendamisel., There is currently a high demand for functional materials that can serve as the basis for the development of new energy-efficient devices and mechanisms with a wide range of applications, capable of operating under various Earth and space conditions. As the first results have shown, rare-earth metal oxyhydrides offer a number of useful functionalities that can be directly utilized in modern technological applications, especially in the design of high-performance optical and electromechanical devices. Chemical engineering of rare-earth metal oxyhydrides has begun more than 10 years ago when it was discovered that the addition of oxygen into the hydride structure not only rearranges the stoichiometry due to the flexible stabilization of hydrogen and oxygen positions in the crystal lattice, but also greatly expands the set of characteristics of the modified metal-hydride system. This has opened up great opportunities to improve a number of key properties of metal hydrides and enhance their functionality, thus enabling researchers to flexibly modify and improve their optical, mechanical, and electronic properties. From a scientific and technological point of view, understanding what functional role the chemical addition of oxygen plays in the properties of solid oxyhydrides is the most important problem. Thus, the main goal of the present PhD thesis was to significantly extend our knowledge about the behavior of oxygen in rare-earth metal hydrides. Using modern methods of mathematics, theoretical physics and crystal chemistry, as well as extensive numerical calculations on a supercomputer, we investigated the most probable structural and compositional configurations in rare-earth metal oxyhydride systems. This allowed us to predict a large number of compounds with different crystal structures and oxygen/hydrogen ratios and construct a ternary phase diagram for Y-H-O variables. We have characterized the key role of oxygen in the formation of new materials, which guides crystallization into a stable oxyhydride structure. Among all ternary oxyhydride compositions, we found that certain oxyhydrides can be stabilized in polar noncentrosymmetric phases that have outstanding elastic, piezoelectric, and electromechanical characteristics. One of these phases corresponds to a special tetragonal structure whose lattice configuration is characterized by a unique chiral structural organization encompassing all cations and anions in the unit cell. Based on the calculated electronic and optical properties, we also proposed two different prototypes of optical coatings in which oxyhydride thin films play a key role: (i) a low-emissivity coating model and (ii) a light-absorbing non-reflective coating model. The results of our research have significantly enriched the knowledge base on the material properties of rare-earth metal oxyhydrides. They revealed details of the microscopic nature of the electronic, elastic, electrical, and optical properties of these materials. This allowed us to understand how their properties and functional characteristics could be driven by various chemical and physical factors. In addition, we proposed possible scenarios for the prediction and design of oxyhydride materials with promising functions, which can be further used in the development of modern optical and electromechanical devices., https://www.ester.ee/record=b5461494

We report the spatial structure of phosphoribosyl pyrophosphate synthetase 2 from the thermophilic bacterium Thermus thermophilus HB27 (TthPRPPS2) obtained at a 1.85 Å resolution using a diffraction set collected from rhombohedral crystals (space group R32-h), grown with lithium sulfate as a precipitant. This crystal structure was compared with the structure of TthPRPPS2, previously obtained at a 2.2 Å resolution using diffraction sets from the tetragonal crystals (space group P41212), grown with ammonium sulfate as a precipitant. The comparison of these structures allows the study of the differences between protein molecules in both crystalline structures, as well as the packaging of enzyme molecules in crystals of both spatial groups. Our results may contribute to the research of the structural basis of catalytic activity and substrate specificity of this enzyme.

Cyclic tests of the multicycle fatigue of commercially pure titanium were performed under normal conditions (without a magnetic field) and after exposure to a constant magnetic field of varying density (B = 0.3, 0.4, 0.5 T). It was shown that the application of the constant magnetic field of varying density led to a fold increase in the average number of cycles to destruction of the VT1-0 titanium samples by 64, 123, and 163%, respectively. Scanning electron microscopy revealed that the magnetic field led to a 1.45-fold increase in the critical length of the fracture (the width of the fatigue crack growth zone) and a 1.6-fold decrease in the distance between the fatigue striations in the accelerated crack growth zone of the destroyed titanium samples. It was established that a subgrain (fragmented) structure formed in the area of the fatigue growth of the fracture of the titanium samples. The size of the subgrains corresponded to the spaces between the fatigue striations, which had an inhibitory influence on the microcrack propagation. Collectively, the revealed facts are indicative of a higher material resistance to fatigue fracture propagation and increased operation resources under the fatigue tests in the magnetic field, which correlates with the data on the growth of the average number of cycles to fracture of the VT1-0 titanium samples.

Rice starch is a common functional ingredient used in various food applications. The drying regime to obtain dry starch powder is an important processing step, which affects the functional properties of the starch. The application of extreme thermal treatment during the conventional drying process tends to elicit irreversible changes to the rice starch, resulting in the loss of desired functionalities. In a previous study, we reported the development of a novel low temperature spray-drying based process which efficiently dries waxy rice starch, while preserving its physicochemical properties and functionalities. This study, a follow-up to the previous report, evaluated the effect of different spray-drying inlet temperatures on the production yield, physicochemical properties, and functionalities of waxy rice starch. Increasing the inlet temperature from 40 °C to 100 °C resulted in an increase in the process yield from 74.83% to 88.66%, respectively. All spray dried waxy rice starches possessed a low moisture content of less than 15%, and a consistent particle size (median ~6.00 μm). Regardless of the inlet temperatures, the physicochemical functionalities, including the pasting characteristics and flowability, were similar to that of the native waxy rice starch. The molecular and A-type crystalline structure of the waxy rice starches were also conserved. An inlet temperature of 60 °C represented the optimum temperature for the spray-drying process, with a good yield (84.55 ± 1.77%) and a low moisture content (10.74 ± 1.08%), while retaining its native physicochemical functionalities and maximizing energy efficacy.

The novel use of ionic liquid as a solvent for biodegradable and natural organic biomaterials has increasingly sparked interest in the biomedical field. As compared to more volatile traditional solvents that rapidly degrade the protein molecular weight, the capability of polysaccharides and proteins to dissolve seamlessly in ionic liquid and form fine and tunable biomaterials after regeneration is the key interest of this study. Here, a blended system consisting of Bombyx Mori silk fibroin protein and a cellulose derivative, cellulose acetate (CA), in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIMAc) was regenerated and underwent characterization to understand the structure and physical properties of the films. The change in the morphology of the biocomposites (by scanning electron microscope, SEM) and their secondary structure analysis (by Fourier-transform infrared spectroscopy, FTIR) showed that the samples underwent a wavering conformational change on a microscopic level, resulting in strong interactions and changes in their crystalline structures such as the CA crystalline and silk beta-pleated sheets once the different ratios were applied. Differential scanning calorimetry (DSC) results demonstrated that strong molecular interactions were generated between CA and silk chains, providing the blended films lower glass transitions than those of the pure silk or cellulose acetate. All films that were blended had higher thermal stability than the pure cellulose acetate sample but presented gradual changes amongst the changing of ratios, as demonstrated by thermogravimetric analysis (TGA). This study provides the basis for the comprehension of the protein-polysaccharide composites for various biomedical applications.

Väitekirja elektrooniline versioon ei sisalda publikatsioone, Komplekssete fosfaatide ja fluoriidide ühendeid kasutatakse laialdaselt biomeditsiinis nende ühilduvuse tõttu bioloogilise koega. Selliseid fosfaatühendeid kasutatakse praegu peamiselt luuimplantaatides, aga samuti suurte implantaatide peal õhukese kattekihina. Nende materjalide dopeerimine haruldaste muldmetallide ioonidega, eriti neodüümiga, avardab nende rakendusvõimalusi. Näiteks, haruldaste muldmetallidega dopeeritud fluoriid-nanoosakesi kolloid-vesilahuses saab kasutada bioloogilise koe visualiseerimiseks (kuni sügavuseni 1 cm), lokaalseks kuumutamiseks, ravimite manustamiseks, jms. Selles kontekstis pakub nii baas- kui ka rakendusteaduse vaatevinklist suurt huvi valguse kiirgamine (fluorestsents) ja selle kustutamise mehhanismid. Fluorestsentsi kustutamise protsessid lõppkokkuvõttes määravad, kas fluorestsentsmaterjali saab kasutada näiteks bioloogilise koe visualiseerimisel, sh sügavamate kudede mitteinvasiivsel kujutamisel. Ühelt poolt on need protsessid ebasoovitavad ja nende minimeerimine suurendab fluorestsentsi intensiivsust. Teiselt poolt, fluorestsentsi kustutamise analüüsimine annab täiendavat infot uuritava materjali lokaalse struktuuri kohta. Väitekirjas käsitletakse detailselt mõlemat aspekti. Pakutakse lihtsad kriteeriumid sobiva kristallilise peremeesmaatriksi valimiseks lisandioonidele, mis minimeeriks fluorestsentsi kustutavad protsessid ja seeläbi suurendaks fluorestsentsi tugevust. Lisaks analüüsitakse fluorestsentsi kustumiskineetikat, et määrata neodüümi ioonidega seotud optiliste tsentrite lokaalset struktuuri tri-kaltsiumfosfaadi mikrokeraamikas, mis on luukoe tehisanaloog. Väitekirja tulemusi saab kasutada haruldaste muldmetallidega dopeeritud fluorestsentsmaterjalide funktsionaalsuse ja sooritusvõime edendamisel mitmesugustes biomeditsiinilistes rakendustes., Complex phosphate and fluoride compounds are widely used in biomedicine due to their compatibility with biological tissues. Compounds of complex phosphates are currently used mainly as bone implants, but also as thin coatings for large implants for better engraftment. Doping of these materials with ions of rare earth (RE) ions, neodymium in particular, makes it possible to expand the area of their application. For example, fluoride compounds in the form of aqueous colloidal solutions of nanoparticles doped with RE ions can be used to visualize biological tissues at a depth of 1 cm, for local thermal heating, drug delivery, etc. In this context, from the point of view of both fundamental and applied science, the study of light radiation (fluorescence) and its quenching is of great interest. Fluorescence quenching processes ultimately determine the possibility of using a fluorescent material, for example, to visualize biological tissue, including non-invasive visualization at great depths. On the one hand, these processes are negative, and minimizing their contribution leads to an increase in the fluorescence intensity. On the other hand, by analyzing the fluorescence quenching processes, one can obtain additional information on the local crystal structure of the studied material. In the thesis, both aspects are discussed in detail. To minimize the quenching processes and, as a consequence, increase the fluorescence brightness, simple criteria are proposed for choosing a crystal matrix for doping with RE ions. In addition, the analysis of the fluorescence impurity quenching kinetics was used to determine the local structure of neodymium ions optical centers in an artificial analogue of bone tissue - tri-calcium phosphate microceramics. The results of the thesis can be used to expand the functions and improve fluorescence materials, doped with RE ions, in particular, for various biomedical applications., https://www.ester.ee/record=b5450805

The single crystals of FeIn2S4, AgIn5S8 compounds and (FeIn2S4)1- x AgIn5S8 solid solutions have been grown with Bridgeman method. Their composition and structure were determined. It is seen that the pointed compounds and solid solutions are crystallized in the spinal cubic structure. The elementary cell parameters calculated with the least square method change linearly. The density of FeIn2S4, AgIn5S8 compounds and their solid solutions were calculated with the pycnometric method. The density and the elementary cell parameter with х compasitions change linearly. The temperatures od phase transformation were determined with the differential thermal analysis and the diagram of the AgIn5S8-FeIn2S4 system state was built.

International audience; A combination of high field solid-state MAS NMR spectroscopy, X-ray diffraction, and firstprinciples calculations is used to elucidate the crystalline structure of CsSc3F10. At room temperature, this phase was found to crystallize in the Pmma (n°51) space group with a = 8.0837(1) Å, b = 7.5764(1) Å, and c = 6.8127(1) Å. The remarkable feature of CsSc3F10 is an unusual high cesium coordination number of 18. 45 Sc-19 F D-HMQC NMR method has been employed to investigate the connectivity of scandium with fluorine atoms. NMR parameters were determined using first principle DFT calculations and compared with experimentally obtained data.

Funding Information: This work was supported by Future Makers 2019 Program (funded by Technology Industries of Finland Centennial Foundation and Jane and Aatos Erkko Foundation ), Business Finland (HeatStock project), Maj and Tor Nessling Foundation ( 201900332 ) and Academy of Finland ( 343192 ). The research made use of OtaNano Nanomicroscopy Center (NMC). The authors wish to thank also M. Sc. Markus Laitinen and B.Sc. Šimon Jech for collecting literature data. Publisher Copyright: © 2022 The Authors During the past decade sugar alcohols have been extensively studied for thermal storage purposes. One of the recent focuses of research has been in improving their heat charge and discharge rate by enhancing the thermal conductivity with different types of additives. However, the current literature shows a vast discrepancy in measured values of sugar alcohols. This work presents an experimental study on thermal conductivity of seven sugar alcohols. The aim is to find out the reason for the discrepancy of literature values for erythritol, mannitol and xylitol, and to present new reference data for galacticol, myo-inositol, maltitol and sorbitol. We study the impact of material preparation method, raw material grade and sensor contact on the crystalline structure and the conductivity. The crystalline structure was inspected with optical and scanning electron microscopy and X-ray diffraction, and melting properties with differential scanning calorimetry. We found that different polymorphs, grain structure and crystallite sizes can be obtained by different preparation methods. This caused the conductivity of mannitol, galacticol and myo-inositol to vary by tens of percentages. Crystallization temperatures of xylitol and erythritol were found to affect their grain size but had only a minor effect on the conductivity. Overall, the conductivities of solid phase sugar alcohols were found to be within the upper range of the previous literature; based on the methods of this work, we did not find any evidence for the low and intermediate values for erythritol, xylitol and mannitol. Due to the high amorphous content of maltitol and sorbitol their conductivity was substantially lower than that of the other sugar alcohols. Thermal conductivity of liquid phases was found to accurately follow a linear relationship with the molar mass for sugar alcohols with carbon number between 4 and 6.

The 3D morphology of hierarchically structured electrocatalytic systems is determined based on multi-scale X-ray computed tomography (XCT), and the crystalline structure of electrocatalyst nanoparticles is characterized using transmission electron microscopy (TEM), supported by X-ray diffraction (XRD) and spatially resolved near-edge X-ray absorption fine structure (NEXAFS) studies. The high electrocatalytic efficiency for hydrogen evolution reaction (HER) of a novel transition-metal-based material system – MoNi4 electrocatalysts anchored on MoO2 cuboids aligned on Ni foam (MoNi4/MoO2@Ni) - is based on advantageous crystalline structures and chemical bonding. High-resolution TEM images and selected-area electron diffraction patterns are used to determine the crystalline structures of MoO2 and MoNi4. Multi-scale XCT provides 3D information of the hierarchical morphology of the MoNi4/MoO2@Ni material system nondestructively: Micro-XCT images clearly resolve the Ni foam and the attached needle-like MoO2 micro cuboids. Laboratory nano-XCT shows that the MoO2 micro cuboids with a rectangular cross-section of 0.5 × 1 µm2 and a length of 10-20 µm are vertically arranged on the Ni foam. MoNi4 nanoparticles with a size of 20-100 nm, positioned on single MoO2 cuboids, were imaged using synchrotron radiation nano-XCT. The application of a deep convolutional neural network (CNN) significantly improves the reconstruction quality of the acquired data.

The laser-assisted melt electrospinning (LES) method was utilized for the preparation of poly(L-lactide-co-ε-caprolactone) (PLCL) fibers. During the process, a carbon dioxide laser was irradiated, and voltage was applied to the raw fiber of PLCL. In situ observation of fiber formation behavior revealed that only a single jet was formed from the swelling region under the conditions of low laser power and applied voltage and feeding rate, whereas multiple jets and shots were produced with increases in these parameters. The formation of multiple jets resulted in the preparation of thinner fibers, and under the optimum condition, an average fiber diameter of 0.77 μm and its coefficient of variation of 17% was achieved without the formation of shots. The estimation of tension and stress profiles in the spin-line was also carried out based on the result of in situ observation and the consideration that the forces originated from surface tension, electricity, air friction, and inertia. The higher peak values of tension and stress appearing near the apex of the swelling region corresponded to the formation of thinner fibers for the condition of single-jet ejection. Analyses of the molecular orientation and crystallization of as-spun fibers revealed the formation of a wide variation of higher order structure depending on the spinning conditions.

Polymorphism is a relatively common phenomenon among pharmaceutical compounds, and one of the main aspects to be considered in the production and development of medications. The investigation of polymorphism associated with oxicams, a group belonging to the class of non-steroidal anti-inflammatory drugs (NSAIDs) has increased in recent years and, in the case of tenoxicam, the existence of four polymorphic forms is reported in the literature. The objective of this study was to characterize the presence of different polymorphic forms of tenoxicam in active pharmaceutical ingredient and oral pharmaceutical formulations, as well as to evaluate the influence on in vitro dissolution. The characterization of the three samples of pharmaceutical ingredient of tenoxicam from different suppliers by X-Ray Diffraction (XRD), Infrared (IR) and dissolution profile indicated the presence of a form III crystalline structure, without presenting significant differences between the in vitro dissolution profiles analyzed, and a Dissolution Efficiency (DE%) of 60.30%, 60.70% and 72.34%, respectively. When the four pharmaceutical specialties of tenoxicam were submitted to XRD analysis, they also presented form III crystalline structures. Despite this, the formulations presented different dissolution profiles and a DE% of 75.23%, 83.69%, 78.19% and 90.63%, respectively, without compromising their quality. However, often polymorphism affects physico-chemical properties of drugs, showing the importance of studying this phenomenon, by correlating the presence of crystalline structures to alterations in the quality of active ingredients and pharmaceutical products.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Manganese (Mn) can develop magnetic properties in substituted hydroxyapatites (HA), as well as iron, copper, cobalt and samarium, but with the advantage of controlling several cellular activities. The occupation of the HA sites by Mn and its segregation from HA structure during heat treatments can affect magnetic properties. For this reason, the objective of this work was to study the accommodation of Mn into a carbonated HA, and its segregation mechanism at temperatures above 800°C yielding Mn3O4 nanoparticles. HAs with five different concentrations of Mn in relation to calcium were synthesized by the aqueous precipitation method: (Mn/(Mn+Ca) = 0, 5, 10, 15 and 20 at. %. Using wavelength dispersion X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, it was possible to demonstrate that Mn was inserted into the HA structure in all concentrations, strongly compromising its crystalline structure. The regions around the hydroxyl channels were affected the most, with clear evidence of preferential Ca2 sites occupation, especially in the samples with a high content of CO3 2- replacing PO4 3- . When carbonate was released at high temperature and the crystallinity increased, the Ca1 sites seemed more susceptible to occupation by Mn. At temperatures above 1000°C, Mn segregated from the HA structure in the form of Mn3O4 nanoparticles, via hydroxyl channels, preferentially occupying Ca2 sites at the final segregation stage. The presence of Mn in several oxidation states also suggested that, in addition to the cationic substitutions, there were also anionic substitutions such as MnO4 3- at the PO4 3- sites. No cytotoxicity was detected for the lower concentration of Mn regarding osteoblastic cells. These results contributed to clarify the Mn behavior into HA and its segregation, being fundamental to the development of new strategies to synthesize magnetic-active hydroxyapatite-based scaffolds in the future. O manganês (Mn) pode desenvolver propriedades magnéticas em hidroxiapatitas (HA) substituídas, assim como o ferro, cobre, cobalto e samário, mas com a vantagem de também controlar diversas atividades celulares. O tipo e grau de ocupação dos sítios da HA e a possibilidade de segregação de óxidos desses elementos durante tratamentos térmicos definem as propriedades magnéticas resultantes. Por essa razão, o objetivo desse trabalho foi estudar de forma preliminar como ocorre a acomodação do Mn nos sítios de uma HA carbonatada, bem como seu mecanismo de segregação em temperaturas acima de 800°C com a formação de nanopartículas de Mn3O4. Para isso, HAs com cinco diferentes concentrações de Mn em relação ao cálcio foram sintetizadas pelo método de precipitação em meio aquoso: (Mn/(Mn+Ca) = 0, 5, 10, 15 e 20 % at. Usando-se fluorescência de raios X por dispersão de comprimento de onda, difração de raios X, espectroscopia no infravermelho com transformada de Fourier, microscopia eletrônica de transmissão e espectroscopia de fotoelétrons de raios X, ficou demonstrando que o Mn foi inserido na estrutura da HA para todas as concentrações, perturbando consideravelmente a sua estrutura cristalina. As regiões dos canais hexagonais de hidroxila sofreram as maiores perturbações, com evidências de ocupação preferencial dos sítios de Ca2, principalmente para as amostras verdes com alto teor de CO3 2- em substituição ao PO4 3- . Quando o CO3 2- é liberado em alta temperatura e a cristalinidade aumenta, os sítios de Ca1 parecem mais suscetíveis à ocupação por Mn. Em temperaturas acima de 1000°C, o Mn tendeu a ser segregado da estrutura da HA na forma de nanopartículas de Mn3O4, via canais de hidroxila, ocupando preferencialmente sítios de Ca2 no estágio final da segregação. A presença de Mn em diversos estados de oxidação também sugeriu que, além das substituições catiônicas, ocorreram também substituições aniônicas de MnO4 3- nos sítios de PO4 3- . Na sua concentração mais baixa, o Mn não apresentou citotoxicidade frente a osteoblastos humanos. Esses resultados são essenciais na compreensão do comportamento do Mn na HA e sua segregação, sendo fundamental para o desenvolvimento de novas estratégias para a produção de arcabouços magnéticos ativos baseados em hidroxiapatita no futuro. São Cristóvão

Natural biopolymers, which are renewable, widely available, biodegradable, and biocompatible, have attracted huge interest in the development of biocomposite materials. Herein, formulation–property relationships for starch/agar composite films were investigated. First, rapid visco analysis was used to confirm the conditions needed for their gelation and to prepare filmogenic solutions. All the original crystalline and/or lamellar structures of starch and agar were destroyed, and films with cohesive and compact structures were formed, as shown by SEM, XRD, and SAXS. All the plasticized films were predominantly amorphous, and the polymorphs of the composite films were closer to that of the agar-only film. FTIR results suggest that the incorporation of agar restricted starch chain interaction and rearrangement. The addition of agar to starch increased both tensile strength and elongation at break, but the improvements were insignificant after the agar content was over 50 wt.%. Contact angle results indicate that compared with the other samples, the 4:6 (wt./wt.) starch/agar film was less hydrophilic. Thus, this work shows that agar dominates the structure and properties of starch/agar composites, and the best properties can be obtained with a certain starch/agar ratio. Such composite polysaccharide films with tailored mechanical properties and surface hydrophilicity could be useful in biodegradable packaging and biomedical applications (wound dressing and tissue scaffolding).

Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2021, Tutor: Jorge Echeverría López, Non-covalent π-hole interactions have been of great scientific interest in recent years given their contribution to the formation of crystalline structures. Several studies have recently been conducted in order to comprehend and characterize such interactions. This work aims to understand the nature of π-hole contacts in lactam crystalline structures, since they are molecules known for their key role in the field of medicine and antibiotics. This project has carried out both a structural and a theoretical analysis of such interactions for various lactam systems, both experimental and computational model based. A first search in the Cambridge Structural Database (CSD) has given us a first notion of the interaction nature and possible contributions involved in it, such as the orbital contribution. Analyses using Density Theory Functional (DFT) and Natural Bond Orbital (NBO) calculations have allowed us to see the orbital contribution implicated in the π-hole contact and studies using Molecular Electrostatic Potential (MEP) and Atoms In Molecules (AIM) calculations have shown us the electrostatic contribution present in such interaction. From the data recollected it has been possible to see how these interactions present bond values that are not negligible in terms of the formation of crystalline structures. It has also been observed that their nature is not merely electrostatic because, despite being small, the orbital contribution governs some interaction parameters such as the attack angle between the donor atom and the acceptor atom

The coining process can be identified as a shallow die forging. By using this proc ess, it is possible to produce very fine surface geometries. This leads to dimension scaling into micro dimensions and causes the specific material behavior. In the micro area, continuum laws are not strictly followed anymore. The leading role in determining the deformation and strain level is taken by the fine surface geometry dimension and the size of the crystalline grain of the workpiece material. This is known as the size effect and defines all micro- forming processes. In order to pro vide monitoring of the filling of the smallest die dimensions, additional supporting procedures should be used. In this case, radiography testing procedures for ob serving the specific points of the workpiece geometry are applied, characterized with very small dimensions (less than 0.5 mm). Testing aluminum samples are formed using two techniques – open and closed die coining, with identical surface geometry. Their crystalline structures are in two- grain sizes of 34 μm and 80 μm. Scanning results show different material behaviour and different surface deforma tion for the same level of forming force in all four testing cases.

Les composés qui existent sous de multiples formes cristallines sont qualifiés de polymorphiques. Les polymorphes ont la même composition, mais leurs structures et leurs propriétés peuvent varier significativement. Dans de nombreux domaines, les conditions de cristallisation des composés d’intérêt sont étudiées de façon exhaustive afin de générer autant de polymorphes que possible, à partir desquels le polymorphe le plus avantageux pour l’application souhaitée peut être sélectionné. Nous rapportons une nouvelle façon d’augmenter la diversité polymorphique basée sur la cristallisation induite par l’ensemencement à l’aide de cristaux mixtes. Nous rapportons également une nouvelle stratégie de cristallisation de composés fondus suspendus qui permet d’induire la formation de cristaux uniques qui sont trop instables pour être produits par des méthodes traditionnelles. Cette stratégie permet la résolution par diffraction des rayons X d’une plus large variété de structures cristallines. L’efficacité des méthodes présentées ci-dessus a été démontrée en les utilisant pour produire des cristaux uniques caractérisés par diffraction des rayons X de nouveaux polymorphes du composé ROY, une référence en matière de polymorphisme. Cela permet à ROY de regagner sa part de la position de composé le plus polymorphique dans la Cambridge Structural Database (CSD)., Chemical compounds that exist in multiple crystalline forms are said to exhibit polymorphism. Polymorphs have the same composition, but their structures and properties can vary markedly. In many fields, conditions for crystallizing compounds of interest are screened exhaustively to generate as many polymorphs as possible, from which the most advantageous form for the desired application can be selected. Here we report a new way to increase polymorphic diversity, based on crystallization induced by suitably designed mixed-crystal seeds. Also reported herein is a new strategy of suspended-melt crystallization, which can be used to induce the formation of single crystals that are too unstable to be produced by traditional methods. This strategy allows for a broader scope of crystalline structures to be resolved by X-ray diffraction. The efficacy of the above methods has been demonstrated by using them to produce new polymorphs of the benchmark compound ROY as single crystals structurally characterized by X-ray diffraction. This allows ROY to reclaim a share of the crown as the most polymorphic compound in the Cambridge Structural Database (CSD).

Environment-friendly medium-density fiberboards (MDFs) prepared using sodium lignosulfonate/chitosan adhesives (L/C) show potential in environment-friendly wood-based panel application. However, the synthesis mechanism of this adhesive and the relationships between synthesis mechanism and bonding performance were not discussed in depth. Herein, the synthesis mechanism of L/C was explored in detail based on characterizations of L/C with different mass ratios of sodium lignosulfonate to chitosan by Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction. For L/C with different mass ratios of sodium lignosulfonate to chitosan, the corresponding bonding performance was also determined based on characterizations of mechanical and dimensional performance of MDFs. Results showed a 3D network structure of L/C formed through the hydrogen linkages among hydroxyl groups in sodium lignosulfonate and hydroxyl and amino groups in chitosan, amide linkages resulted from reaction between carbonyl groups in sodium lignosulfonate and amino groups in chitosan, and sulfonamide linkages originated from reaction between sulfonic groups in sodium lignosulfonate and amino groups in chitosan. The mechanical performance of MDF was closely related to the 3D network and amino groups of L/C, while the dimensional performance of MDF was negatively affected by sodium lignosulfonate. The MDFs with 1:3 and 1:2 mass ratios of sodium lignosulfonate to chitosan showed superior mechanical properties and comparable dimensional performance with a commercial panel.

Sweet potato is a root tuber crop and an important starch source. There are hundreds of sweet potato varieties planted widely in the world. Starches from varieties with different genotype types and originating from different countries have not been compared for their physicochemical properties. In the research, starches from 44 sweet potato varieties originating from 15 countries but planted in the same growing conditions were investigated for their physicochemical properties to reveal the similarities and differences in varieties. The results showed that the 44 starches had granule size (D[4,3]) from 8.01 to 15.30 μm. Starches had different iodine absorption properties with OD680 from 0.259 to 0.382 and OD620/550 from 1.142 to 1.237. The 44 starches had apparent amylose content from 19.2% to 29.2% and true amylose content from 14.2% to 20.2%. The starches exhibited A-, CA-, CC-, or CB-type X-ray diffraction patterns. The thermograms of 44 starches exhibited one-, two-, or three-peak curves, leading to a significantly different gelatinization temperature range from 13.1 to 29.2 °C. The significantly different starch properties divide the 44 sweet potato varieties into different groups due to their different genotype backgrounds. The research offers references for the utilization of sweet potato germplasm.

Objective: This study aimed to develop a microstructured lipid carrier that improves the rate of dissolution of the active pharmaceutical ingredient (API) Albendazole. Methods: A solvent diffusion method was used for the development of microstructured lipid carriers. The developed carriers were characterized by optical microscopy, infrared spectroscopy, differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and dissolution testing. Results: The morphology of the carriers was irregular, and their size tends to decrease with the addition of modifiers. Furthermore, the diffractograms and the thermograms indicated a loss of crystallinity. The thermograms and infrared spectra showed that there are not chemical incompatibilities between the API and the excipients. When the lipid carrier particles were modified with Aerosil® 200 (specifically when using this excipient at a level of 6% w/w), dissolution was increased up to 85.96±1.17 % of the drug content as per USP test for Albendazole tablets in comparison with 36.13±0.52 % for a lipid carrier formulation without modifiers. Conclusion: It was demonstrated that it is possible to develop a modified lipid carrier that improves the dissolution rate of an API with a low solubility, which was related to the amorphization of the API crystalline structure. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones Farmacéuticas (INIFAR)

Starch constitutes a promising resource for biodegradable packaging, but it presents several processing drawbacks when using conventional industrial equipment, such as flat-die extrusion. This work demonstrates that the replacement of native cassava starch (NS) with commercial hydrolyzed (HS) or carboxymethyl (CMS) starches diminishes the amount of energy required to process starch granules into thermoplastic films by extrusion. Homogeneous films with starch-glycerol interaction improvements are obtained when using HS or CMS instead of NS. HS films exhibit the lowest crystallinity and the highest susceptibility to water among the studied systems. Likewise, CMS films maximize Vh crystalline structure fraction and present higher Young's modulus and stress at break, and lower water vapor permeability values. In order to combine the positive properties and to overcome the limitations of each modified starch, blend films from HS:CMS (50:50 wt%) are also developed and investigated. Phase separation is observed in this system, and there are no improvements in the overall properties. The results of this investigation show that employing commercial CMS, even in very low carboxymethylation degree represents a successful strategy to improve mechanical and barrier properties of flat-die extruded films, while HS can be used to obtain water-soluble films for specific applications. Fil: Guz, Lucas Martín. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: González Seligra, Paula Fabiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Ochoa Yepes, Oswaldo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Estevez Areco, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Fama, Lucia Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina Fil: Goyanes, Silvia Nair. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina

The decrease in electrical properties caused by the toughening of polypropylene (PP) is a difficult problem for the modification of PP used for cable insulation. In this research, an isotactic PP, a cross-linked polyethylene (XLPE) and two impact PP copolymers (IPCs) with an ethylene&ndash, propylene rubber phase content of 15 and 30% were prepared to assess the possibility of IPCs to be used as cable insulating material. The tensile properties and breakdown strength were evaluated, meanwhile, the rubber phase content dependence of the crystalline structure, morphology and trap distribution were also investigated. Results show that IPCs with a 15% rubber phase content (IPC15) can achieve the simultaneous improvement of elongation at break and breakdown strength compared with isotactic PP, which can be attributed to the special crystalline structure. According to the results of differential scanning calorimetry (DSC) and FTIR, it is proposed that the lamella thickness of IPC15 is maximal and some ethylene segments exist in PP crystals of IPC15 as crystalline structure defects, which is responsible for this enhanced breakdown strength. The morphology results reveal that rubber microspheres are found to coexist with spherulites, which can promote the relative sliding among lamellas under external force and further results in the increase in the elongation at break.