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Herein, we investigate silicate-phosphate glasses from the SiO2–P2O5–K2O–MgO–SO3 system enriched with various amounts of sulfur, as a nutrient indispensable for the proper development of plants, in order to gain a profound understanding of the structure of such materials. An inherent capability of glasses from the studied system to incorporate sulfate groups into the vitreous matrix was discussed on the basics of the results from XRF, XRD and internal Al2O3 standard techniques. It has been found, that as much as 3 mol.% of SO3 can be loaded into the glass batches to obtain fully amorphous material, while beyond this limit K2SO4 crystallizes within the matrix. Comprehensive spectroscopic investigation, comprising Raman, Middle Infrared (MIR), 29Si and 31P MAS-NMR, X-ray absorption spectroscopy (XANES and XAS) techniques, has been implemented in order to determine an impact of sulfur on silicate-phosphate glass framework. On this basics, it has been concluded, that sulfur exists in the vitreous matrix in the form of specific domains, in which [SO4]2- anions are surrounded by the shell of charge-compensating K+ cations. Such sulfate groupings maintain their individuality without direct bonding to silico-oxygen or phospho-oxygen subnetwork. Spectroscopic results revealed also, that the presence of sulfur affects silico-oxygen subnetwork to a significantly greater extent than the phospho-oxygen one. It has been demonstrated, that along with SO3 addition, the more polymerized Q S i 3 units increase in abundance at the expense of less polymerized Q S i 2 groups. Results of the present study are believed to contribute to a greater understanding of the nature of sulfur-bearing oxide glasses.

Levofloxacin is considered an alternative treatment option of Stenotrophomonas maltophilia infections to trimethoprim/sulfamethoxazole. The fluoroquinolone resistance in S. maltophilia is usually caused by an overproduction of efflux pumps. In this study, the contribution of efflux systems to levofloxacin resistance in S. maltophilia clinical isolates was demonstrated using phenotypic (minimal inhibitory concentrations, MICs, of antibiotics determination ± efflux pump inhibitors, EPIs) and molecular (real-time polymerase-chain-reaction and sequencing) methods. Previously, the occurrence of genes encoding ten efflux pumps was shown in 94 studied isolates. Additionally, 44/94 isolates demonstrated reduction in susceptibility to levofloxacin. Only 5 of 13 isolates (with ≥4-fold reduction in levofloxacin MIC) in the presence of EPIs showed an increased susceptibility to levofloxacin and other antibiotics. The overexpression of smeD and smeV genes (in five and one isolate, respectively) of 5 tested efflux pump operons was demonstrated. Sequencing analysis revealed 20–35 nucleotide mutations in local regulatory genes such as smeT and smeRv. However, mutations leading to an amino acid change were shown only in smeT (Arg123Lys, Asp182Glu, Asp204Glu) for one isolate and in smeRv (Gly266Ser) for the other isolate. Our data indicate that the overproduction of the SmeVWX efflux system, unlike SmeDEF, plays a significant role in the levofloxacin resistance.

In this survey, we review the classical Hamilton-Jacobi theory from a geometric point of view in different geometric backgrounds. We propose a Hamilton-Jacobi equation for different geometric structures attending to one particular characterization: whether they fulfill the Jacobi and Leibniz identities simultaneously, or if at least they satisfy one of them. This property reviews the work of the present authors in such a way that it is presented according to a hierarchy of nested brackets. This is a new outlook in which we do not only present the geometric structures themselves, but their hierarchical relations and how they affect their dynamic through the Hamilton-Jacobi equation. In this regard, we review the case of time-dependent (t-dependent in the sequel) and dissipative physical systems as systems that fulfill the Jacobi identity but not the Leibnitz identity, as instances of cosymplectic and contact mechanical problems. Let us remark that dissipative here means dissipation provided by a dissipation parameter included in the Hamiltonian function, for instance, the entropy in some thermodynamical systems. Furthermore, we review the contact-evolution Hamilton-Jacobi theory as a split off the regular contact geometry, and that actually satisfies the Leibniz rule instead of Jacobi. Furthermore, we include a novel result, which is the Hamilton-Jacobi equation for conformal Hamiltonian vector fields as a generalization of the well-known Hamilton-Jacobi on a symplectic manifold, that is retrieved in the case of a zero conformal factor. The interest of a geometric Hamilton-Jacobi equation is the primordial observation that if a Hamiltonian vector field X H can be projected into a configuration manifold by means of a one-form dW, then the integral curves of the projected vector field XHdW can be transformed into integral curves of X H provided that W is a solution of the Hamilton-Jacobi equation. Geometrically, the solution of the Hamilton-Jacobi equation plays the role of a Lagrangian submanifold of a certain bundle. Exploiting these features in different geometric scenarios we propose a geometric theory for multiple physical systems depending on the fundamental identities that their dynamic satisfies. Different examples are pictured to reflect the results provided, being all of them new, except for one that is reassessment of a previously considered example. Finally, let us mention that an important issue in the study of the Hamilton-Jacobi equation is separability, relevant for finding conserved quantities. However, we will not deal with this subject in this survey, although we refer the reader to papers [16, 17, 136]., Manuel de León acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN), under Grants PID2019-106715GB-C21, EIN2020-11210, and "Severo Ochoa Programme for Centres of Excellence in R&D" (CEX2019-000904-S).

We show that in a uniform thickness NiO(111)/Fe(110) epitaxial bilayer system, at given temperature near 300 K, two magnetic states with orthogonal spin orientations can be stabilized in antiferromagnetic NiO. Field-free, reversible switching between these two antiferromagnetic states is demonstrated. The observed phenomena arise from the unique combination of precisely tuned interface magnetic anisotropy, thermal hysteresis of spin reorientation transition and interfacial ferromagnet/antiferromagnet exchange coupling. The possibility of field-free switching between two magnetic states in an antiferromagnet is fundamentally interesting and can lead to new ideas in heat assisted magnetic recording technology.

Simple Summary Nosocomial infections caused by Stenotrophomonas maltophilia have been increasing worldwide. These bacteria are intrinsically resistant to most antibiotics. The underestimated resistance mechanism of Gram-negative rods is an overexpression of multidrug-resistant (MDR) efflux pumps. The aim of this study was to analyze the genetic diversity of isolates derived from various clinical materials, including blood, and the prevalence of MDR efflux pump genes and susceptibility profiles to the anti-S. maltophilia drugs. The research was conducted on 94 S. maltophilia isolates derived from hospitalized patients and outpatients in Warsaw, Poland. All isolates were susceptible to trimethoprim-sulfamethoxazole and minocycline, while 44/94 isolates demonstrated reduction in susceptibility to levofloxacin. A large genetic variation was observed among these isolates. However, a clonal relationship was revealed among two groups of bloodstream isolates from one hospital ward: (1) nine isolates, (2) six isolates. Moreover, the presence of genes encoding ten different efflux pumps from the resistance-nodulation-division family and the ATP-binding cassette family was shown in the majority of the 94 isolates. The obtained knowledge about the prevalence of efflux pump genes in clinical S. maltophilia strains makes it possible to predict the scale of the risk of resistance emergence in strains as a result of gene overexpression. Abstract An increase of nosocomial infections caused by Stenotrophomonas maltophilia strains has recently been observed all over the world. The isolation of these bacteria from the blood is of particular concern. In this study we performed the phenotypic and genotypic characterization of 94 S. maltophilia isolates, including isolates from patients hospitalized in a tertiary Warsaw hospital (n = 79) and from outpatients (n = 15). All isolates were found to be susceptible to trimethoprim-sulfamethoxazole and minocycline, while 44/94 isolates demonstrated a reduction in susceptibility to levofloxacin. A large genetic variation was observed among the isolates tested by pulsed-field gel electrophoresis. A clonal relationship with 100% similarity was observed between isolates within two sub-pulsotypes: the first included nine bloodstream isolates and the second involved six. Multilocus sequence typing showed two new sequence types (ST498 and ST499) deposited in public databases for molecular typing. Moreover, the presence of genes encoding ten different efflux pumps from the resistance-nodulation-division family and the ATP-binding cassette family was shown in the majority of the 94 isolates. The obtained knowledge about the prevalence of efflux pump genes in clinical S. maltophilia strains makes it possible to predict the scale of the risk of resistance emergence in strains as a result of gene overexpression.

The control of the spin orientation in antiferromagnets is of key importance in modern spintronics. Here, the authors demonstrate controllable antiferromagnetic spin switching in a synthetically fabricated epitaxial ferromagnet/antiferromagnet bilayer. Thanks to the precise nanoengineering of ferromagnet anisotropy and interface exchange coupling, two orthogonal spin states in the antiferromagnet can be either thermally stabilized in a field-free manner or written by a small external magnetic field.

Virgin and Yb-implanted epitaxial ZnO films grown using atomic layer deposition (ALD) were investigated by X-ray absorption spectroscopy (XAS). XAS study revealed a strong polarization dependence of films determined by the orientation of the polarization vector of the synchrotron radiation to the sample surface. It also indicated that the implantation and subsequent annealing have an important influence on the native point defect complexes in the ZnO. Comparison of experimental spectra with the modelled ones, which are computed based on the linear combination of model spectra corresponding to the selected point defects and their complexes, confirmed the presence of donor-acceptor complexes (mVZn - nVO, m = 1,4; n = 1,2) in the samples under study. The mechanism of vacancy complexes formation is unclear as it takes place under non-equilibrium conditions, for which any theoretical method has not been well established. Exploring the 3 d → 4 f absorption, it was found that oxidation state of Yb in ZnO is 3+, which is consistent with the XPS findings and previously conducted Resonant Photoemission Spectroscopy (RPES) investigations. The inversion of the polarization dependence for samples with different Yb fluences visible in Yb M5 spectra can be associated with a tilt of the oxygen pseudo octahedra or/and with their distortion. The analysis of the presented data suggests that the donor-acceptor complexes are present both in as grown and implanted films and may influence their electrical properties. This suggestion was confirmed by previous Hall measurements showing that the resistivity of annealed ZnO:Yb film with a fluence of 5e15 ions/cm2 decreases by about one order compared to the one with a fluence of 5e14 ions/cm2.

We report on exchange bias and interfacial antiferromagnetic spin orientation in epitaxial CoO(111)/Fe(110) bilayers. Our X-ray magnetic linear dichroism and magneto-optic Kerr effect results show that exchange bias sets on in the zero-field-cooled system and is governed by in-plane magnetic state Fe(110) sublayer above Neel temperature of CoO. Uniaxial magnetic anisotropy of Fe layer determines the direction of interfacial frozen antiferromagnetic CoO spins within CoO(111)//Fe(110) sample plane. Choice of the particular magnetic state of Fe sublayer, when passing Neel temperature of CoO, determines both the axis and direction of interfacial antiferromagnetic spins after the sample is cooled and allows for imprinting their +/- 90° and 0/180° alignment within the sample plane.

We have applied positron annihilation spectroscopy to study the formation of Ga vacancy related defects in Mg and Mn doped bulk GaN crystals grown by the ammonothermal method. We show that Mn doping has little or no effect on the formation of Ga vacancies, while Mg doping strongly suppresses their formation, in spite of both dopants leading to highly resistive material. We suggest the differences are primarily due to the hydrogen-dopant interactions. Further investigations are called for to draw a detailed picture of the atomic scale phe-nomena in the synthesis of ammonothermal GaN.

Both preserved gapless states and gapping of Dirac states due to broken time reversal symmetry in bismuth chalcogenide topological insulators with surface and bulk magnetic impurities have been observed and reported in the literature. In order to shed more light on the mechanism of such effects we have performed comprehensive element selective study of the impact of Fe impurity position in the Bi2Se3 lattice on its magnetism. The iron atoms were imbedded in the structure (volume dopants) or deposited on the surface (adatoms) and they revealed striking phenomena. Volume doping preserves non-trivial topology of Bi1.98Fe0.02Se3. Fe atoms not only substitute Bi, but also locate in van der Waals gap. The former are magnetically isotropic, while the latter reveal large magnetic moment (4.5 μ B) with perpendicular anisotropy if located near the surface. Majority of Fe adatoms on the surface of Bi2Se3 exhibit weaker moment (3.5 μ B) with in-plane anisotropy, as expected for non-interacting species. Negligible interaction between surface electronic states and magnetic adatoms is confirmed by identical vibration spectra of Fe deposited on TI surface of Bi2Se3 and non-TI surface of Bi2S3. The data gathered show how indispensable is the knowledge of the magnetic impurity distribution for applications of bismuth chalcogenide systems.

An attempt is undertaken to chemically modify YMnO3+δ by the partial substitution of Y with larger Nd and Sm, aiming to boost the oxygen storage performance in the temperature swing process. Single-phase (P63cm) Y0.95Nd0.05MnO3+δ and Y0.95Sm0.05MnO3+δ compounds are obtained in a sol-gel auto-combustion process followed by the annealing at 1000 °C in Ar. Both materials show improved oxygen storage capacity, however, doping with Nd3+ enables the effective operation in air – capacity reached 1453 μmol-O g−1, which is over 86% of the capacity in O2. As documented for the Nd-containing sample, oxygen absorption is accompanied by oxidation of Mn3+ to Mn4+, and no changes in the valence of neodymium occur. The reversible oxygen intake and release occur at exceptionally low temperatures for Y0.95Nd0.05MnO3+δ, as low as in the 201–240 °C range. This enables utilization of the recovery of low- and medium-temperature waste heat. In addition, the paper presents the impact of the preparation route of the material on the oxygen storage-related performance. It is shown that lowering of the annealing temperature allows to further increase the rate of O2 absorption, making the material a promising candidate for practical application, however, it results also in the presence of the secondary phases. © 2021 The Authors

The common approach to modify the thermoelectric activity of oxides is based on the concept of selective metal substitution. Herein, we demonstrate an alternative approach based on the formation of multiphase composites, at which the individual components have distinctions in the electric and thermal conductivities. The proof-of-concept includes the formation of multiphase composites between well-defined thermoelectric Co-based oxides: Ni, Fe co-substituted perovskite, LaCo0.8Ni0.1Fe0.1O3 (LCO), and misfit layered Ca3Co4O9. The interfacial chemical and electrical properties of composites are probed with the means of SEM, PEEM/XAS, and XPS tools, as well as the magnetic susceptibility measurements. The thermoelectric power of the multiphase composites is evaluated by the dimensionless figure of merit, ZT, calculated from the independently measured electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (λ). It has been demonstrated that the magnitude’s electric and thermal conductivities depend more significantly on the composite interfaces than the Seebeck coefficient values. As a result, the highest thermoelectric activity is observed at the composite richer on the perovskite (i.e., ZT = 0.34 at 298 K).

Solaris is a third generation light source built and commissioned at the Jagiellonian University in Krakow. It is a replica of the MAX IV 1.5 GeV storage ring and part of its injector. The commissioning of the storage ring started in May 2015. First light at the bending magnet beamline front end was observed after two weeks of optimisation. After one year of commissioning excellent performance of the Solaris synchrotron has been achieved. Injection into the storage ring occurs at the designed electron energy of 525 MeV, next the beam is ramped to the final energy of 1.5 GeV. Beam optics has been adjusted to be close to the design one. Solaris is operating at a working point of (11.22, 3.15) and with a corrected chromaticity of (+0.93, +0.91). Recently over 600 mA of beam current was stored for injection energy. The vacuum system of the storage ring is still being conditioned. After about 90 A.h of beam cleaning dose the total beam lifetime at 100 mA is approaching 11 h at 1.5 GeV. So far two beamlines have been constructed. The UV angle-resolved photoemission spectroscopy (UARPES) beamline with a photon energy range from 8 eV to 100 eV, is in commissioning since April 2016 and the soft X-ray spectroscopy dedicated PEEM/XAS beamline from a bending magnet source, which is at the end of its installation phase. This paper reports on the current status of the Solaris facility and the commissioning results.

In this article, the results of computational structural studies on Al-containing zeolites, via periodic DFT + D modelling and FDM (Finite Difference Method) to solve the Schrödinger equation (FDMNES) for XAS simulations, corroborated by EXAFS (Extended X-ray Absorption Fine Structure) spectroscopy and PXRD (powder X-ray diffractometry), are presented. The applicability of Radial Distribution Function (RDF) to screen out the postulated zeolite structure is also discussed. The structural conclusions are further verified by HR-TEM imaging.

The trial was undertaken to measure the amount of different types of seeds industrial hemp. Photonic analysis was used to make measurements which bases on counting the amount of emitted photons from standardized sample within estimated time interval. Photon emission tests were carried out in the Laboratory of Experimental Research Techniques of Raw Materials and Biological Products with PCA accreditation in the subject measurement procedure.

A ferromagnet/antiferromagnet (FM/AFM) Fe/NiO bilayer was grown using molecular beam epitaxy on MgO(001) and Cr buffered MgO(001) substrates. X-ray linear dichroism measurements showed a dominating out-of-plane component for the NiO spins in Fe/NiO/MgO and an in-plane spin direction for NiO layers grown on the Cr buffer. Furthermore, systematic studies on the magnetic properties of Fe/NiO grown on the wedge-shaped Cr buffer revealed a continuous strain-induced spin reorientation transition from out-of-plane to in-plane NiO spin directions when the Cr thickness increased from 0 nm to 3.5 nm. The analysis of the in-plane magnetic structure of NiO in Fe/NiO/Cr showed a pronounced uniaxial anisotropy in thin AFM layers. The AFM spins are perpendicular to the Fe spins due to spin–flop interaction. These results demonstrate the feasibility of using strain and coupling with FMs to manipulate spin structures in NiO.

We show that in a uniform thickness NiO(111)/Fe(110) epitaxial bilayer system, at given temperature near 300 K, two magnetic states with orthogonal spin orientations can be stabilized in antiferromagnetic NiO. Field-free, reversible switching between these two antiferromagnetic states is demonstrated. The observed phenomena arise from the unique combination of precisely tuned interface magnetic anisotropy, thermal hysteresis of spin reorientation transition and interfacial ferromagnet/antiferromagnet exchange coupling. The possibility of field-free switching between two magnetic states in an antiferromagnet is fundamentally interesting and can lead to new ideas in heat assisted magnetic recording technology.

Antiferromagnet/ferromagnet (AFM/FM) bilayers that display the exchange bias (EB) effect have been subjected to intensive material research, being the key elements of novel spintronics systems. In a commonly accepted picture, the antiferromagnet, considered as a rigid material due to its high anisotropy and magnetic hardness, controls the magnetic properties of the ferromagnet, such as a shift of the hysteresis loop or coercivity. We show that this AFM-FM master-slave hierarchy is not generally valid and that the influence of the ferromagnet on the magnetic anisotropy (MA) of the neighbouring antiferromagnet must be considered. Our computer simulation and experimental studies of EB in an epitaxial CoO/Fe(110) bilayer show that the ferromagnetic layer with strong uniaxial magnetic anisotropy determines the interfacial spin orientations of the neighbouring AFM layer and rotates its easy axis. This effect has a strong feedback on the EB effect experienced by the FM layer. Our results show new physics behind the EB effect, providing a route for grafting a desired anisotropy onto the AFM and for precise tailoring of EB in AFM/FM systems.

The aim of the project is to monographically describe the history of popular science periodicals that were published on Polish lands until the year 1939. A collection of approx. 200 titles published in the Polish language, addressed to both adult readers as well as children and adolescents, published individually or as part of a publication will be analysed. It is planned to prepare a bibliography of periodicals, which will be the basis for conducting a multifaceted analysis of the studied phenomenon, in the designated time intervals and to detect the differences as well as the similarities that occur during these time periods. A hypothesis has been formed that these journals, that are an important element of permanent learning accompanying the recipient throughout his/her life, have been subject to transformation, both in terms of form and contents. By conducting the analyses, we aim to seek the general regularities that have shaped the popular science magazine market during the studied period, to indicate its determinants, trends, relations with the institutional and social environment and to demonstrate that their setting up was supported by patriotic, educational, practical and cultural making reasons. The starting point for the research will be to redefine the term "popular science journal", in order to eliminate terminology confusion. The next step will bet to create a database of bibliographic titles, which will be discussed in the context of press studies (quantitative development, publishing centres, frequency, publishers, durability, profile, circulation, pictorialness, internal structure) having in mind the political and pedagogical context, as well as the context of cultural studies and the study of science. The picked out typological groups and their main representatives will be described in detail. Studies concerning the evolution of the internal structure, the language and form of expression, the origins of the texts, layout, and the evolution of design as an important element affecting the reception of the presented contents as well as its typology, shall also be included. The phenomenon, namely the evolution of a popular science magazine’s shape, that is the transition from imitating foreign templates to creating one’s own model based on national material and collaboration with Polish scholars, will also be presented. The following methods will be used in the study: the bibliographic method (collection and verification of data), written and formal contents analysis (description of the individual titles and their categorization), methods used for the systemizing and interpretation of press photographs, compositional interpretation, a iconographic and iconological method of analysing a work of art, statistical techniques (comparative analysis). The aim of the project is to prepare a comprehensive analysis of the popular science periodicals of the chosen time intervals. The research results will determine not only the their quantitative development, their transformation in terms of form and contents, but also their functions and tasks in the changing political and social conditions on Polish lands. Acknowledgement of the popular science magazine as an information medium, will allow to acquire knowledge about the scope and coverage of the presented contents, the changes in understanding the essence of popularization and its functions and the level of program tasks implementation. The results of the conducted studies will interest media experts, bibliologists, cultural history scholars, historians of science and literary scholars. The conducted research will fill in a missing gap in the history of Polish press, it may contribute to undertake monographic studies of individual titles, since they have not so far been presented in a monography. This group of magazines is also ignored in comprehensive summaries on the history of Polish press. The faint interest of the researchers, and consequently a little progress being made, was primarily caused by the lack of basic research in the areas of registration and documentation, as well as the lack of a quantitative and qualitative analysis of the studied phenomenon.

Acireductone dioxygenase (ARD) is an intriguing enzyme from the methionine salvage pathway that is capable of catalysing two different oxidation reactions with the same substrate depending on the type of the metal ion in the active site. To date, the structural information regarding the ARD–acireductone complex is limited and possible reaction mechanisms are still under debate. The results of joint experimental and computational studies undertaken to advance knowledge about ARD are reported. The crystal structure of an ARD from Homo sapiens was determined with selenomethionine. EPR spectroscopy suggested that binding acireductone triggers one protein residue to dissociate from Fe(2+), which allows NO (and presumably O(2)) to bind directly to the metal. Mössbauer spectroscopic data (interpreted with the aid of DFT calculations) was consistent with bidentate binding of acireductone to Fe(2+) and concomitant dissociation of His88 from the metal. Major features of Fe vibrational spectra obtained for the native enzyme and upon addition of acireductone were reproduced by QM/MM calculations for the proposed models. A computational (QM/MM) study of the reaction mechanisms suggests that Fe(2+) promotes O—O bond homolysis, which elicits cleavage of the C1—C2 bond of the substrate. Higher M(3+) /M(2+) redox potentials of other divalent metals do not support this pathway, and instead the reaction proceeds similarly to the key reaction step in the quercetin 2,3-dioxygenase mechanism.

W artykule omówiono dotychczasowe badania nad polskimi czasopismami popularnonaukowymi wydawanymi do 1939 roku. Zaprezentowano również projekt badawczy realizowany z funduszy Narodowego Centrum Nauki, mający na celu monografi czne ujęcie dziejów czasopiśmiennictwa popularnonaukowego na ziemiach polskich do 1939 roku. The article presents research on the Polish popular-science journals until 1939. A research project was carried out with the funds of the National Science Centre and it refers to a monographic approach of the history of the Polish popular-science journals until 1939.

The first Polish synchrotron radiation facility Solaris is being built at the Jagiellonian University in Krakow. The project was approved for construction in February 2010 using European Union structural funds. The Solaris synchrotron is based on the 1.5 GeV facility being built for the MAX IV project at Lund University in Sweden. A general description of the facility is given together with a status of its implementation. The specific Solaris solutions taken for the linear accelerator, beamlines and civil engineering infrastructure are outlined.

The authors have applied contactless electroreflectance (CER) spectroscopy to study the epi readiness of m-plane GaN substrates obtained by the ammonothermal method. It has been clearly observed that the CER resonance, which is related to the energy gap transition, appears for samples with a well-polished surface. The sharpness of this resonance is directly related to the surface quality. The broadening of energy gap transition can be used as a parameter to quantify the surface quality. For samples polished with optimal conditions, this broadening (γpol) is close to the broadening observed for the cleaved GaN surface (γclev) with m-plane orientation (150–190 vs 135 meV). The quality of the polishing process can be evaluated by analyzing the γclev/γpol ratio, where γclev/γpol=1 corresponds to an excellent polishing process. In the authors’ case, this ratio has been determined to be close to 1 for well-polished samples.

AlGaN/GaN high electron mobility transistors on semi-insulating bulk ammonothermal GaN have been investigated. By application of regrown ohmic contacts, the problem with obtaining low resistance ohmic contacts to low-dislocation high electron mobility transistor (HEMT) structures was solved. The maximum output current was about 1 A/mm and contact resistances was in the range of 0.3&ndash, 0.6 &Omega, &middot, mm. Good microwave performance was obtained due to the absence of parasitic elements such as high access resistance.

Series of Fe3O4/MgO(001) and Fe3O4/Fe/MgO(001) films (single- and bi-layer films, respectively) with a total layer thickness in the range of 20¥150 nm were investigated by the Rutherford backscattering spectrometry (2 MeV He+ ion beam), by the Rutherford backscattering spectrometry channeling experiments (1.5 MeV He+ ion beam). Depending on the layer thickness of each layer and the film geometry, a single Fe peak and/or a double-anomaly feature was revealed in the Rutherford backscattering spectra. For all films no magnesium presence in the surface layer was observed. For both single- and bi-layer films with a total layer thickness less than 60 nm only one minimum was observed in the channeling curves, while a double minimum was revealed for the bi-layer films with a larger thickness. X-ray reflectometry measurements have revealed that the film density is the same as that of the bulk one.

The structural and magnetic properties of ultrathin FeO(111) films on Pt(111) with thicknesses from 1 to 16 monolayers (ML) were studied using the nuclear inelastic scattering (NIS) of synchrotron radiation. Distinct evolution of vibrational characteristics with thickness that is revealed in the phonon density of states (PDOS) witnesses a textbook transition from 2D to 3D lattice dynamics. For the thinnest films of 1 and 2 ML, the low energy part of the PDOS followed a linear dependence in energy that is characteristic for 2-dimensional systems. This dependence gradually transforms with thickness to the bulk ~E-square relation. Density functional theory phonon calculations perfectly reproduced the measured 1 ML PDOS within a simple model of a pseudomorphic FeO/Pt(111) interface. The calculations show that the 2D PDOS character is due to a weak coupling of the FeO film to the Pt(111) substrate. The evolution of the vibrational properties with an increasing thickness is closely related to a transient long range magnetic order and stabilization of an unusual structural phase.

Background. Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in western civilization. The accumulation of CD5 + CD19 + B lymphocytes in peripheral blood is due to a defect in the apoptotic pathway rather than excessive proliferation in the bone marrow and lymph nodes. Despite a number of treatments, CLL remains an incurable disease. Valproic acid (VPA) activity, as a histone deacetylase inhibitor, could restore the epigenetic changes underlying the pathogenesis of CLL and thus induce cell death. Objectives. In the present study we hypothesized that VPA could induce CLL primary cells death through activation of apoptosis. Material and Methods. Peripheral blood samples were obtained from 53 CLL patients. Peripheral blood mononuclear cells were isolated through density gradient centrifugation and were the subject of a 24-hour cell culture with 10 mM of VPA. The cytotoxic effect of VPA was evaluated with an XTT test and thereafter confirmed using Annexin V-FITC/PI staining and flow cytometry techniques. Results. In this study, a median VPA cytotoxicity of 13.88% with a range of 0-54.65% was observed. Annexin V/PI staining confirmed that the demonstrated cytotoxicity was caused by increased apoptosis in the VPA treated cells as compared to control cells. Statistical analysis showed that VPA’s effect on CLL cells depends on lactate dehydrogenase serum levels, but is independent of all other prognostic markers. Conclusions. The results of the present experiments found that VPA at a clinically applicable concentration significantly induces apoptosis independently of the disease stage and might be a valuable therapeutic agent for all CLL patients (Adv Clin Exp Med 2015, 24, 1, 55-62).

The valence band photoemission spectra of epitaxially grown 300 Ǻ single crystalline magnetite films were measured by the angle-resolved ultraviolet photoemission spectroscopy (ARUPS) at 300 K. The samples were grown either on MgO(0 0 1) (B termination) or on (0 0 1) Fe (iron-rich A termination), thus intentionally presenting different surface stoichiometry, i.e. also different surface electronic states. Four main features of the electron photoemission at about −1.0, −3.0, −5.5 and −10.0 eV below a chemical potential show systematic differences for two terminations; this difference depends on the electron outgoing angle. Our studies confirm sensitivity of angle resolved PES technique on subtleties of surface states.

Magnetic and elastic properties of Ni metal have been studied up to 260 GPa by nuclear forward scattering of synchrotron radiation with the 67.4 keV M\"ossbauer transition of $^{61}\mathrm{Ni}$. The observed magnetic hyperfine splitting confirms the ferromagnetic state of Ni up to 260 GPa, the highest pressure where magnetism in any material has been observed so far. Ab initio calculations reveal that the pressure evolution of the hyperfine field, which features a maximum in the range of 100 to 225 GPa, is a relativistic effect. The Debye energy obtained from the Lamb-M\"ossbauer factor increases from 33 meV at ambient pressure to 60 meV at 100 GPa. The change of this energy over volume compression is well described by a Gr\"uneisen parameter of 2.09.

Background Dextromethorphan (DXM) is the analogue of codeine, available in Poland and many European countries without prescription (OTC drug). In the last decade we have observed a considerable increase in non-medical usage of dextromethorphan among young age groups, especially school children between 13 and 16 yrs. Methods We analysed the “trip reports” after use of DXM, available on a website: hyperreal.info in the years 1999-2013. The Internet users could …

The adsorption of oxygen on a pseudomorphic iron monolayer deposited on a W(110) surface was studied experimentally and theoretically. Standard surface characterization methods, such as Auger electron spectroscopy and low energy electron diffraction, and specific nuclear methods, such as conversion electron Mössbauer spectroscopy (CEMS) and nuclear resonant scattering of synchrotron radiation, combined with theoretical calculations based on the density functional theory allowed us to determine the structure of the oxygen adsorbate and the electronic properties of iron atoms with different oxygen coordinations. The oxygen-(3 × 2) structure on the iron monolayer was recognized and was interpreted to be a state with oxygen chemisorbed on the non-reconstructed surface with modest electron transfer from iron to oxygen. A transition from chemisorbed oxygen to the onset of Fe-oxidation is revealed by distinct changes in the CEMS spectra., Highlights • The early O2 adsorption on pseudomorphic Fe monolayer on W(110) was studied. • Using LEED we have identified several distinct structures. • Electronic properties were probed using conversion electron Mössbauer spectroscopy. • The O-(3 × 2) structure was resolved based on DFT calculations. • A transition from chemisorption to Fe-oxidation was demonstrated.

Permittivity, the dielectric loss tangent and conductivity of semi-insulating Gallium Nitride crystals have been measured as functions of frequency from 10 GHz to 50 GHz and temperature from 295 to 560 K employing quasi TE0np mode dielectric resonator technique. Crystals were grown using ammonothermal method. Two kinds of doping were used to obtain high resistivity crystals; one with deep acceptors in form of transition metal ions, and the other with shallow Mg acceptors. The sample compensated with transition metal ions exhibited semi-insulating behavior in the whole temperature range. The sample doped with Mg acceptors remained semi-insulating up to 390 K. At temperatures exceeding 390 K the conductivity term in the total dielectric loss tangent of Mg compensated sample becomes dominant and it increases exponentially with activation energy of 1.14 eV. It has been proved that ammonothermal method with appropriate doping allows growth of high quality, temperature stable semi-insulating GaN crystals.

Nuclear inelastic-scattering studies were performed to infer temperature evolution of iron atom dynamics in magnetite samples exhibiting Verwey transition of first- and second-order (type-I and type-II materials). The possible difference in this evolution could rationalize the distinct properties of these classes of materials observed in heat capacity and diffuse scattering below the Verwey transition temperature ${T}_{V}$ and could explain the change in transition order triggered by a minute (below 0.3$%$) altering of the iron sublattice. Although we have found the apparent stiffening of the phonon iron spectrum in the low-temperature phase, at the same time, we have shown that these spectra are rather similar for type-I and type-II materials, rendering the lattice vibration-based explanation of the distinct behavior of heat capacities very improbable. The calculation of phonon spectra, aimed at tracing the origin of various features in the phonon density of states (DOS), has shown that the local Coulomb interaction $U$ may have a large effect on phonon DOS. However, the change in the $U$ parameter cannot explain the difference in heat-capacity results for both classes of materials. Thus, an additional factor that differentiates these materials and possibly is responsible for the discontinuous character of the Verwey transition in stoichiometric magnetite still must be found.

We investigate the dynamical properties of the non-heme iron (NHFe) in His-tagged photosynthetic bacterial reaction centers (RCs) isolated from Rhodobacter (Rb.) sphaeroides. Mössbauer spectroscopy and nuclear inelastic scattering of synchrotron radiation (NIS) were applied to monitor the arrangement and flexibility of the NHFe binding site. In His-tagged RCs, NHFe was stabilized only in a high spin ferrous state. Its hyperfine parameters (IS=1.06±0.01mm/s and QS=2.12±0.01mm/s), and Debye temperature (θD0~167K) are comparable to those detected for the high spin state of NHFe in non-His-tagged RCs. For the first time, pure vibrational modes characteristic of NHFe in a high spin ferrous state are revealed. The vibrational density of states (DOS) shows some maxima between 22 and 33meV, 33 and 42meV, and 53 and 60meV and a very sharp one at 44.5meV. In addition, we observe a large contribution of vibrational modes at low energies. This iron atom is directly connected to the protein matrix via all its ligands, and it is therefore extremely sensitive to the collective motions of the RC protein core. A comparison of the DOS spectra of His-tagged and non-His-tagged RCs from Rb. sphaeroides shows that in the latter case the spectrum was overlapped by the vibrations of the heme iron of residual cytochrome c2, and a low spin state of NHFe in addition to its high spin one. This enabled us to pin-point vibrations characteristic for the low spin state of NHFe.

Room temperature contactless electroreflectance (CER) has been applied to study optical transitions and the distribution of the built-in electric field in AlGaN/GaN heterostructures grown on c-, a-, m-, and (20.1)-plane GaN substrates obtained by the ammonothermal method. It has been clearly shown that polarization effects in the AlGaN/GaN heterostructures grown on the c-plane lead to a strong built-in electric field in the AlGaN layer. The aforementioned field was determined to be ∼0.43 MV/cm from the period of Franz–Keldysh oscillations (FKOs). In addition, polarization effects lead to the formation of a two dimensional electron gas at the AlGaN/GaN interface, which screens the band bending modulation in the GaN buffer layer, and, therefore, GaN-related excitonic transitions are not observed for this heterostructure. Such features/effects are also not observed in the AlGaN/GaN heterostructures grown on nonpolar and semipolar GaN substrates because any strong polarization effects are not expected in this case. For these heterostructures, very strong and sharp GaN excitonic resonances are clearly visible in CER spectra. The resonances are very similar to the excitonic transitions observed for the GaN epilayers deposited on nonpolar and semipolar substrates. Moreover, there is a very weak AlGaN-resonance without FKO for nonpolar and semipolar heterostructures instead of the strong AlGaN-related FKO, which is typical of polar AlGaN/GaN heterostructures.

Monochromatization of hard X-rays in the 20–40 keV energy range to ∼1 meV bandwidth using a sapphire backscattering monochromator is demonstrated., A sapphire backscattering monochromator with 1.1 (1) meV bandwidth for hard X-rays (20–40 keV) is reported. The optical quality of several sapphire crystals has been studied and the best crystal was chosen to work as the monochromator. The small energy bandwidth has been obtained by decreasing the crystal volume impinged upon by the beam and by choosing the crystal part with the best quality. The monochromator was tested at the energies of the nuclear resonances of 121Sb at 37.13 keV, 125Te at 35.49 keV, 119Sn at 23.88 keV, 149Sm at 22.50 keV and 151Eu at 21.54 keV. For each energy, specific reflections with sapphire temperatures in the 150–300 K region were chosen. Applications to nuclear inelastic scattering with these isotopes are demonstrated.