Search

Luminescence properties of Li2MgGeO4:Ln3+ (Ln = Pr, Tm) depend significantly on the excitation wavelengths. Several emission bands are observed, which can be assigned to ceramic matrix and characteristic transitions of Pr3+ and Tm3+ ions.

Background: Oxalate ligand-based metal complexes have long been used for the thermal synthesis of metal oxides. Polymeric homo/heterometallic oxalate-based molecular materials of the general formula, {A]MIIMIII[C2O4]3]}∞, [A = organic cation, MII/MIII: di/trivalent transition metal ion; C2O4: oxalate ligand] provides a molecular source to prepare metal oxides through solid state thermal decomposition primarily due to the potential to tune the materials’ outcome by adjusting the molecular stoichiometry and composition. Objective: The study aims to explore the effect of mixing at the di- and trivalent metal sites of {N[n-C4H9]4]FeIIFeIII[C2O4]3]}∞ which decomposes to hematite, on the nature of thermal decomposition reaction as well as the nature of the obtained decomposed materials. Methods: Two series of materials {N[n-C4H9]4]FeII 1-xZnII xFeIII[C2O4]3]}∞ and {N[n- C4H9]4]FeIIFeIII 1-xCrIII x[C2O4]3]}∞ were prepared as precursors for non-isothermal thermogravimetry [TG] study. Model-free integral isoconversional method is employed to calculate the activation energy of decomposition, and hence the most probable reaction mechanism, as well as the reaction rate of thermal decomposition, was determined. Based on the kinetic parameters, the important thermodynamic parameters such as the changes of entropy, enthalpy, and Gibbs free energy are estimated for the activated complex formation from the precursors. Powder X-ray diffraction studies were made to identify the decomposed materials. Results: For materials with 0 < x ≤ 1 well-defined two-step and one-step decomposition process were observed for {N[n-C4H9]4]FeII 1-xZnII xFeIII[C2O4]3]}∞ and {N[n- C4H9]4]FeIIFeIII 1-xCrIII x[C2O4]3]}∞, respectively. For each series of materials, a systematic dependence of the activation energy on the extent of conversion indicates a systematic change in the reactivity. The thermal decomposition strongly depends on the extent of mixing at the di- and trivalent sites and proceeds through different reaction mechanisms at different rates. On the decomposition of these series of materials, a range of metal oxides was obtained. Possibly, during such extent of mixing dependent reactions, the reactant particles go through modifications in their reactivity by several factors. Conclusion: Present work may invoke interest in solid state synthesis of different metal oxides under controlled thermal decomposition by identifying the rate controlling the process through reaction kinetics study for better synthesis and manoeuvring.

This work concerns the search for new ways to modify the surface of the biomedical Ti–13Zr–13Nb alloy for applications in regenerative medicine and personalized medicine. Obtained for the first time, oxide nanotubes (ONTs) layers of first-generation (1G) on a Ti–13Zr–13Nb alloy were produced by anodizing in 0.5% HF electrolyte at 20 V for 120 min. The physico-chemical characterization of the obtained bamboo-inspired 1G ONTs was conducted using TEM and ATR-FTIR methods. In vitro corrosion resistance of the 1G ONTs and comparative Ti–13Zr–13Nb substrate in saline solution at 37 °C was conducted by open-circuit potential, Tafel curves, anodic polarization curves, and EIS methods. LEIS and SVET study of local corrosion resistance was also carried out. It was found that surface modification by anodizing of the Ti–13Zr–13Nb alloy under proposed conditions allowed to obtain porous ONTs highly resistant to pitting corrosion. The obtained results give a new insight into the relationship between the morphological parameters of first-generation oxide nanotubes and in vitro corrosion resistance of the Ti–13Zr–13Nb alloy in saline solution at the macro- and microscale.

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 crystallization kinetics and structure evolution during annealing of the Ni45.5Co4.5Mn36.6In13.4 (at. %) powders produced by mechanical alloying (MA) was investigated. After 70 h and 100 h of MA, the powder consisted of a mixture of amorphous and nanocrystalline body-centered cubic (bcc) phases. We observed the relaxation in the as-received powder. The relaxation temperature (Tre) increases logarithmically with the annealing time. Annealing above 440 °C results in (1) ordering of L21, (2) dissolution of the residual Ni and Mn, (3) tetragonal MnNi phase formation and (4) γ phases precipitation. The activation energies of the B2 → L21 and Mn (α-Mn) → MnNi (P4/mmm) transformations were calculated.

Thalliomelane, a new member of the coronadite group (hollandite supergroup), was discovered at Zalas near Kraków in southern Poland (the southern margin of the Kraków-Silesia Monocline) in relics of a preglacial supergene mineralization disseminated in a fault breccia in Middle Jurassic sandy limestone. The mineralization formed at the expense of a sulfide assemblage, which was most likely the source of thallium, related to rejuvenation of Early-Paleozoic fault zones in the Sava phase of the Alpine orogeny. Thalliomelane occurs rarely and exclusively in the form of fibrous and highly porous tiny aggregates

This work compares the dielectric properties of two new materials. One was 0.88 bismuth manganite–0.12 lead titanate (noted BM–PT hereafter) ceramics composite obtained by standard high-temperature sintering. The second composite was obtained from powdered ceramics dispersed in epoxy glue (noted BM–PT–epoxy). The occurrence of four phases in the ceramics, using X-ray powder diffraction (XRD), was recognized: orthorhombic Pbam, cubic Pn 3 ‾ m, cubic Pm 3 ‾ m, and monoclinic P2/m phase. Pseudo-Voigt function fitting confirmed significant structural disorder in the BiMn2O5 crystal lattice. Analysis of broadband dielectric spectroscopy data confirmed the applicability of the small polaron model to explain detected relaxation processes. Involvement of oxygen vacancies in relaxation and their correspondence to ordered, uniform potential wells in crystal lattices was deduced. Electric conductivity relaxation times behavior proved the sensitivity of the ceramics’ electrical features to hydrostatic pressure. BM–PT–epoxy composite exhibited dielectric permittivity and losses two orders of magnitude lower than those of BM–PT ceramics that opened new prospects to application. One relaxation process in BM–PT–epoxy composite related to the ceramics fill contribution. Other induced relaxation, observed only in this composite, was attributed to interactions at interfaces between the introduced powdered ceramics and the epoxy glue matrix. We showed that stresses generated either by hydrostatic pressure or through the interfacial interaction of epoxy matrix led to the same results: relaxation times shortening.

The properties and the shape memory effect depend, among other things, on chemical composition, as well as the method of shape memory alloy (SMA) production. One of the manufacturing methods that leads to the amorphous/nanocrystalline SMA is high-energy ball milling combined with annealing. Using this technique, an SMA memory alloy, with the nominal chemical composition of Ni25Ti50Cu25, was produced from commercial elemental powders (purity −99.7%). The structure and morphology were characterized (at the various stages of its production) by the use of X-ray diffraction, as well as electron microscopy (both scanning and transmission). Choosing the appropriate grinding time made it possible to produce an NiTiCu alloy with a different crystallite size. Its average size changed from 6.5 nm (after 50 h) to about 2 nm (100 h). Increasing the grinding time up to 140 h resulted in the formation of areas that showed the B19 martensite and the Ti2(Ni,Cu) phase with the average crystallite size of about 6 nm (as milled). After crystallization, the average size increased to 11 nm.

In this work, we compare the dielectric properties of single-crystal and pelletized perovskite-like formamidinium-templated inorganic–organic hybrid [NH2CHNH2][Mn(HCOO)3] (FAMn) at ambient pressure. Furthermore, we report pressure-dependent dielectric measurements of pelletized FAMn that allow us to determine the equation of state, as well as changes in the dielectric properties and the rotational motion of formamidinium (FA) cations in the crystal lattice under mechanical stress. Our experiments show that the mechanism of FA cation motion is complex, encompassing six different reorientation paths around three two-fold symmetry axes. Multiple reorientation possibilities of FA cations inside the crystal lattice lead to their irregular molecular dynamics. High-pressure experiments allowed observing that formate anions together with manganese cations form a rigid skeleton, which is stable over a wide temperature and pressure range. Consequently, the hydrostatic pressure exerts a surprisingly small influence on the FA dynamics compared to the related compounds containing the same type of molecular cations. Finally, we reveal a different role of interactions between the A-site organic and the B-site metal cations with the X-site linkers in controlling the dynamics of the A-site moieties under various pressure–temperature conditions. Our results are supported by the molecular dynamics simulations.

The 5-aminolevulinic acid (5-ALA) prodrug is widely used in clinical applications, primarily for skin cancer treatments and to visualize brain tumors in neurosurgery. Unfortunately, its applications are limited by unfavorable pharmacological properties, especially low lipophilicity; therefore, efficient nanovehicles are needed. For this purpose, we synthesized and characterized two novel water-soluble fullerene nanomaterials containing 5-ALA and D-glucuronic acid components. Their physicochemical properties were investigated using NMR, XPS, ESI mass spectrometry, as well as TEM and SEM techniques. In addition, HPLC and fluorescence measurements were performed to evaluate the biological activity of the fullerene nanomaterials in 5-ALA delivery and photodynamic therapy (PDT); additional detection of selected mRNA targets was carried out using the qRT-PCR methodology. The cellular response to the [60]fullerene conjugates resulted in increased levels of ABCG2 and PEPT-1 genes, as determined by qRT-PCR analysis. Therefore, we designed a combination PDT approach based on two fullerene materials, C60-ALA and C60-ALA-GA, along with the ABCG2 inhibitor Ko143.

The systematic studies of the extrinsic Maxwell–Wagner–Sillars polarization process in compressed antimony sulfoiodide (SbSI) nanowires are carried out by dielectric spectroscopy. The dielectric response is studied in temperature (100≤T≤350) K and frequency (10−3≤f≤106) Hz ranges. Dielectric functions commonly used for the analysis of dielectric spectra related to intrinsic polarization processes were applied in the elaboration of experimental data. It was found that the respective “semi-circles” in the Cole–Cole-type plots display a characteristic pear-like shape for the ferroelectric phase. On the other hand, the data for the paraelectric phase form symmetrical arcs. This response is effectively parametrized using the experimental Cole–Davidson and Cole–Cole functions fitted to the data obtained for the ferroelectric and paraelectric phases, respectively. It is deduced that the particular shape of spectra in the ferroelectric phase is due to spontaneous polarization, which is responsible for an asymmetric broadening of relaxation functions related to the interfacial polarization.

The presented work was focused on investigating the influence of the (hafnium and zirconium)/molybdenum ratio on the microstructure and properties of Ti20Ta20Nb20(ZrHf)20−xMox (where: x = 0, 5, 10, 15, 20 at.%) high entropy alloys in an as-cast state. The designed chemical composition was chosen due to possible future biomedical applications. Materials were obtained from elemental powders by vacuum arc melting technique. Phase analysis revealed the presence of dual body-centered cubic phases. X-ray diffraction showed the decrease of lattice parameters of both phases with increasing molybdenum concentration up to 10% of molybdenum and further increase of lattice parameters. The presence of two-phase matrix microstructure and hafnium and zirconium precipitates was proved by scanning and transmission electron microscopy observation. Mechanical property measurements revealed decreased micro- and nanohardness and reduced Young’s modulus up to 10% of Mo content, and further increased up to 20% of molybdenum addition. Additionally, corrosion resistance measurements in Ringers’ solution confirmed the high biomedical ability of studied alloys due to the presence of stable oxide layers.

The presented work aimed to investigate the influence of the hafnium/(zirconium and molybdenum) ratio on the microstructure, microhardness and corrosion resistance of Ti20Ta20Nb20(ZrMo)20−xHfx (where x = 0, 5, 10, 15 and 20 at.%) high entropy alloys in an as-cast state produced from elemental powder and obtained via the vacuum arc melting technique. All studied alloys contained only biocompatible elements and were chosen based on the thermodynamical calculations of phase formation predictions after solidification. Thermodynamical calculations predicted the presence of multi-phase, body-centered cubic phases, which were confirmed using X-ray diffraction and scanning electron microscopy. Segregation of alloying elements was recorded using elemental distribution maps. A decrease in microhardness with an increase in hafnium content in the studied alloys was revealed (512–482 HV1). The electrochemical measurements showed that the studied alloys exhibited a high corrosion resistance in a simulated body fluid environment (breakdown potential 4.60–5.50 V vs. SCE).

In the past twenty years, the basic investigation of innovative Non-Linear Optical (NLO) crystals has received significant attention, which has built the crucial heritage for the use of NLO materials. Fundamental research is essential given the scarcity of materials for NLO compounds, especially in the deep ultraviolet (DUV) and middle- and far-infrared (MFIR) regions. In the present work, we synthesized high-quality MFIR SbI3·3S8 NLO crystals having a length in the range of 1–5 mm through rapid facile liquid phase ultrasonic reaction followed by the assistance of instantaneous natural evaporation phenomenon of the solvent at room temperature. X-ray diffraction (XRD) results ratify the hexagonal R3m structure of SbI3·3S8 crystal, and energy-dispersive X-ray spectroscopy (EDX) demonstrates that the elemental composition of SbI3·3S8 crystal is similar to that of its theoretical composition. The direct and indirect forbidden energy gaps of SbI3·3S8 were measured from the optical transmittance spectra and they were shown to be 2.893 eV and 1.986 eV, respectively. The green sparkling signal has been observed from the crystal during the second harmonic generation (SHG) experiment. Therefore, as inorganic adducts are often explored as NLO crystals, this work on the MFIR SbI3·3S8 NLO crystal can bring about additional investigations on this hot topic in the near future.

In the past decades, para-terphenyls have been attracting tremendous attention due to their polymorphism and conformational diversity. In this work we report the synthesis, crystal structure, polymorphism and dielectric properties of two 2,2′′-bis-substituted para-terphenyls: 2,2′′-bis(hydroxymethyl)-para-terphenyl and 2,2′′-bis(acetyloxymethyl)-para-terphenyl. On the basis of calorimetric and X-ray studies, we showed that the latter compound occurs in at least four polymorphic forms with melting points equal to 364, 345, 341 and 326 K, differentiated also in terms of thermodynamic stability and crystal symmetry. The most stable polymorph I is characterized by the P21/n space group. 2,2′′-Bis(hydroxymethyl)-para-terphenyl crystallizes in the monoclinic P21/c space group. Both 2,2′′-bis-substituted para-terphenyls can undergo vitrification, which is a highly exceptional feature for this class of chemical compounds and has not been reported before. Consequently, the molecular dynamics and conformational changes in the glassy and supercooled liquid states were analyzed by means of IR and broadband dielectric spectroscopy. Two relaxation processes were observed for both compounds: structural α-relaxation, connected with reorientational motions of molecules in supercooled liquid, and intermolecular γ-relaxation, ascribed to rotational motions of substituents of the para-terphenyl skeleton. Taking into account the ongoing discussion about the conformational diversity of the para-terphenyl skeleton, we showed that although free rotation of benzene rings is suppressed, the molecules in the glassy and liquid states can adopt both twisted and helical conformations, which results in diversity of the polymorphic forms.

International audience; It is a paradox that the excess of carbon dioxide in our atmosphere can endanger lives and even the civilisation that has been founded on carbon. Human addiction to carbon is persistent and therefore we need novel chemistry for the efficient conversion of CO2 to harmless or useful products. Accordingly, catalytic CO2 hydrogenation has been widely studied as a potential method for fuel engineering, and methane production in particular. Syngas, a blend of CO with H2 has been observed as an incomplete product of this reaction. Here we report a surprising discovery that syngas to methane conversion can be attained in flow at temperatures starting from-7 °C with a hybrid bimetallic Ru/Ni catalyst. In turn, the ultra-low temperature effect cannot be observed for the Re/Ni and Pd/Ni combinations. To our knowledge, this is the first report showing that such a process can be performed at a temperature lower than the freezing point of water. These ultra-low temperature conditions could potentially lead to sustainable methane production.

In this paper, the transparent oxyfluoride glass-ceramic materials containing YF3:Eu3+ nanocrystals were fabricated via controlled ceramization of precursor xerogels at relatively low temperature T = 350 °C. The formation of YF3 nanocrystalline phase from Y(CF3COO)3 was verified based on X-ray diffraction (XRD) measurements as well as high-resolution transmittance electron microscopy (HR-TEM). Based on IR-ATR spectroscopy the functional groups inside sol-gel structures were identified. The optical properties of Eu3+ ions in fabricated sol-gel samples were investigated based on photoluminescence excitation and emission spectra as well as luminescence decay analysis of the 5D0 excited level. Upon excitation at near-UV illumination, λexc = 393 nm, the series of 4f6-4f6 photoluminescence bands of Eu3+ ions in reddish-orange light area were recorded. The Stark splitting of photoluminescence bands, double-exponential character of decay curves and long-lived emission for fabricated glass-ceramic samples clearly evidenced the partial substitution of Y3+ by optically active Eu3+ ions in precipitated YF3 nanocrystals. Indeed, it was identified that applied annealing conditions resulted in significant, almost 34-fold prolongation of luminescence lifetime from 0.24 ms (Eu3+ ions in xerogel host) up to 8.14 ms (Eu3+ ions incorporated into YF3 nanocrystals). It was also observed a clear correlation between identified phonon energies from IR measurements and luminescence behavior of Eu3+ ions.

A polycrystalline Ni45.5Co4.5Mn36.6In13.4 alloy was obtained by mechanical alloying during high energy ball milling. As-milled powders after 2.5 h, 5 h, 10 h, 15 h, 20 h, 30 h, 40 h, 50 h, 60 h and 70 of milling were studied in terms of structure, particle size and morphology, martensitic transformation. Selected powders were cold pressed and two-step sintered at 1253 K for 0.5 h and then at 1173 K for 24 h, followed by quenching into the ice-water mixture. The structure was examined by X-ray diffraction and electron microscopy. After 30 h of milling, solid-solution of nanocrystalline NiCoMnIn alloy with disordered body-centered cubic structure was observed. The microstructure of sintered samples revealed precipitates of γ particles inside of the matrix B2 grains, creating ‘subgrains’ of the matrix. The estimated average size of subgrains was around 60-70 μm.

The mechanical anisotropy of a multifunctional titanium alloy, Gum Metal, is investigated in this paper. The structural characterisation showed a strong texture for Gum Metal, that is a resul...

The aim of the present study was to assess the influence of the milling time (10 h, 15 h and 20 h) on the structure and properties of Ti-10Ta-8Mo (wt.%) and Ti-10Ta-8Mo-3Sn (wt.%) alloys for potential biomedical application. In addition, the influence of the addition of 3 wt% Sn on the structure and properties of the milled and sintered materials was investigated. X-ray diffraction confirmed the partial synthesis and formation of the β phase during the milling process. The transmission electron microscope analysis of the bright and dark field images and the diffraction image proved the nanocrystalline nature of the material after being subjected to 20h milling duration. The scanning electron microscope observation of the sintered samples confirmed the influence of the milling time and presence of Sn on the microstructure of the obtained material. Furthermore, a small addition of Sn led to better size homogenization by establishing a better balance between the cold-welding and agglomeration processes. At the same time yielding different structures of pores for the sintered samples. The dry sliding tests revealed the excellent friction properties and wear rate of the samples previously milled for 15 h, with the addition of Sn.

The present work is devoted to the magnetic behaviour of Mn12-stearate single-molecule magnets ( [ Mn 12 O 12 ( CH 3 ( CH 2 ) 16 CO 2 ) 11 ( CH 3 CO 2 ) 5 ( H 2 O ) 4 ] · 2 CH 3 COOH ) immobilized inside the SBA-15 mesoporous silica. The stearate’s complexed Mn12, in contrast to the commonly used Mn12-acetate, is soluble in most organic solvents and resistant against water catalyzed reduction. Thus, the precise functionalization of SBA-15 silica by these molecules is possible with no use of sophisticated laboratory equipment. The modified silica matrix in this case provides controlled separation of magnetic molecules, by the use of anchoring units placed inside pores. In order to check the properties of Mn12-stearate molecules regularly distributed inside silica matrix, and check their interactions, samples containing three different concentration of Mn12-stearate molecules were prepared and compared with the bulk Mn12-stearate. All materials have been examined by means of infrared spectroscopy, transmission electron microscopy, X-ray diffraction and squid magnetometry. The obtained results confirmed the successful immobilization of magnetic molecules inside the silica matrices. Moreover, the results of magnetic tests showed a correlation between the amount of magnetic molecules placed inside the mesopores and the magnetic properties of the obtained hybrid materials.

Recent data indicate that modifications to carotenoid biosynthesis pathway in plants alter the expression of genes affecting chemical composition of the cell wall. Phytoene synthase (PSY) is a rate limiting factor of carotenoid biosynthesis and it may exhibit species-specific and organ-specific roles determined by the presence of psy paralogous genes, the importance of which often remains unrevealed. Thus, the aim of this work was to elaborate the roles of two psy paralogs in a model system and to reveal biochemical changes in the cell wall of psy knockout mutants. For this purpose, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR associated (Cas9) proteins (CRISPR/Cas9) vectors were introduced to carotenoid-rich carrot (Daucus carota) callus cells in order to induce mutations in the psy1 and psy2 genes. Gene sequencing, expression analysis, and carotenoid content analysis revealed that the psy2 gene is critical for carotenoid biosynthesis in this model and its knockout blocks carotenogenesis. The psy2 knockout also decreased the expression of the psy1 paralog. Immunohistochemical staining of the psy2 mutant cells showed altered composition of arabinogalactan proteins, pectins, and extensins in the mutant cell walls. In particular, low-methylesterified pectins were abundantly present in the cell walls of carotenoid-rich callus in contrast to the carotenoid-free psy2 mutant. Transmission electron microscopy revealed altered plastid transition to amyloplasts instead of chromoplasts. The results demonstrate for the first time that the inhibited biosynthesis of carotenoids triggers the cell wall remodelling.

The paper describes the physical characterization of CdS nanoparticles, green synthesized using Termitomyces heimii mushroom extract. The CdS samples obtained are wurtzite type. The amount of extract used for synthesis affects the particle size. FT-IR spectra confirmed the presence of proteins as well as the formation of CdS. A blue shift of the absorption maximum based on particle size was observed in the UV–Vis spectra. The size of the nanocrystallites estimated from the XRD and UV–Vis studies were in 3–5 nm range which is in conformity with the results obtained from the SEM and TEM studies. Electronic polarizability of the CdS samples has been estimated. The study presents a simple, cost effective and eco-friendly method of CdS nanoparticle (size

The quasi-static and high strain rate compressive behavior of Gum Metal with composition Ti-36Nb-2Ta-3Zr-0.3O (wt pct) has been investigated using an electromechanical testing machine and a split Hopkinson pressure bar, respectively. The stress–strain curves obtained for Gum Metal tested under monotonic and dynamic loadings revealed a strain-softening effect which intensified with increasing strain rate. Moreover, the plastic flow stress was observed to increase for both static and dynamic loading conditions with increasing strain rate. The microstructural characterization of the tested Gum Metal specimens showed particular deformation mechanisms regulating the phenomena of strain hardening and strain softening, namely an adiabatic shear band formed at ~ 45 deg with respect to the loading direction as well as widely spaced deformation bands (kink bands). Dislocations within the channels intersecting with twins may cause strain hardening while recrystallized grains and kink bands with crystal rotation inside the grains may lead to strain softening. A constitutive description of the compressive behavior of Gum Metal was proposed using a modified Johnson–Cook model. Good agreement between the experimental and the numerical data obtained in the work was achieved.

This paper presents two water-soluble fullerene nanomaterials (HexakisaminoC60 and monoglucosamineC60, which is called here JK39) that were developed and synthesized as non-viral siRNA transfection nanosystems. The developed two-step Bingel–Hirsch reaction enables the chemical modification of the fullerene scaffold with the desired bioactive fragments such as d-glucosamine while keeping the crucial positive charged ethylenediamine based malonate. The ESI–MS and 13C-NMR analyses of JK39 confirmed its high Th symmetry, while X-ray photoelectron spectroscopy revealed the presence of nitrogen and oxygen-containing C–O or C–N bonds. The efficiency of both fullerenes as siRNA vehicles was tested in vitro using the prostate cancer cell line DU145 expressing the GFP protein. The HexakisaminoC60 fullerene was an efficient siRNA transfection agent, and decreased the GFP fluorescence signal significantly in the DU145 cells. Surprisingly, the glycofullerene JK39 was inactive in the transfection experiments, probably due to its high zeta potential and the formation of an extremely stable complex with siRNA.

Laser cutting technology is one of the basic approaches used for thermal processing of parts fabricated from almost all engineering materials. Various types of lasers are utilized in the industry with different attendant gases such as nitrogen or argon. When the laser beam interacts with a metal surface, the area underneath is heated to the melting point. This liquid or vaporized metal is ejected from the kerf area to the surrounding atmosphere by attendant gas and becomes undesirable waste in the form of powder. In the presented work, the X-ray diffraction, scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy methods were used to analyze AISI 304 stainless steel, which was cut by a semiconductor fiber laser, and the waste powder generated during the laser cutting process. The results suggest that this waste material may be reused for industrial applications such as additive manufacturing.

In recent decades, several novel Ti alloys have been developed in order to produce improved alternatives to the conventional alloys used in the biomedical industry such as commercially pure titanium or dual phase (alpha and beta) Ti alloys. Gum Metal with the non-toxic composition Ti–36Nb–2Ta–3Zr–0.3O (wt. %) is a relatively new alloy which belongs to the group of metastable beta Ti alloys. In this work, Gum Metal has been assessed in terms of its mechanical properties, corrosion resistance and cell culture response. The performance of Gum Metal was contrasted with that of Ti–6Al–4V ELI (extra-low interstitial) which is commonly used as a material for implants. The advantageous mechanical characteristics of Gum Metal, e.g. a relatively low Young's modulus (below 70 GPa), high strength (over 1000 MPa) and a large range of reversible deformation, that are important in the context of potential implant applications, were confirmed. Moreover, the results of short- and long-term electrochemical characterization of Gum Metal showed high corrosion resistance in Ringer's solution with varied pH. The corrosion resistance of Gum Metal was best in a weak acid environment. Potentiodynamic polarization studies revealed that Gum Metal is significantly less susceptible to pitting corrosion compared to Ti–6Al–4V ELI. The oxide layer on the Gum Metal surface was stable up to 8.5 V. Prior to cell culture, the surface conditions of the samples, such as nanohardness, roughness and chemical composition, were analyzed. Evaluation of the in vitro biocompatibility of the alloys was performed by cell attachment and spreading analysis after incubation for 48 h. Increased in vitro MC3T3-E1 osteoblast viability and proliferation on the Gum Metal samples was observed. Gum Metal presented excellent properties making it a suitable candidate for biomedical applications.