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We show ferromagnetic properties of hydrogen-functionalized epitaxial graphene on SiC. Ferromagnetism in such a material is not directly evident as it is inherently composed of only nonmagnetic constituents. Our results nevertheless show strong ferromagnetism with a saturation of 0.9μB/hexagon projected area, which cannot be explained by simple magnetic impurities. The ferromagnetism is unique to hydrogenated epitaxial graphene on SiC, where interactions with the interfacial buffer layer play a crucial role. We argue that the origin of the observed ferromagnetism is governed by electron correlation effects of the narrow Si dangling bond states in the buffer layer exchange coupled to localized states in the hydrogenated graphene layer. This forms a quasi-three-dimensional ferromagnet with a Curie temperature higher than 300 K. [ABSTRACT FROM AUTHOR]

Abstract: The magnetization (magnetic susceptibility), specific heat and electrical resistivity of a PrRhIn5 single crystal were studied. Van Vleck-type paramagnetic behavior and strong magnetocrystalline anisotropy were observed, which is attributed to a strong crystal-field effect on the Pr3+ ion. A crystal-field effect on the electrical resistivity was observed as well. We focused on the measurement of the specific heat down to low temperatures (down to 0.4K) in different magnetic fields. Indications of a field-induced transition to the quadrupolar ordered state below 0.4K were found in the specific-heat data in magnetic fields. First-principles calculations based on density functional theory of the electronic structure and crystal-field interaction were performed in order to better understand the experimental findings. [Copyright &y& Elsevier]

Abstract: CeCu0.7Al3.3 single crystals have been prepared by the solution growth method. The compound crystallizes in the tetragonal BaAl4-type of structure with lattice parameters a=4.262Åand c=10.776Å. A detailed specific-heat study of CeCu0.7Al3.3 is presented. The data confirm ferromagnetic order below T C =4K. The estimated Kondo temperature lies also around 4K. The electronic specific-heat coefficient was found to be moderately enhanced over the values for common metallic compounds. It is shown that the energy splitting between the ground state and the first excited doublet amounts to 75K at least, which is considerably higher than the value deduced from magnetization data. [Copyright &y& Elsevier]

Many current research efforts in strongly correlated systems focus on the interplay between magnetism and superconductivity. Here we report on coexistence of both cooperative ordered states in recently discovered stoichiometric and fully inversion symmetric heavy fermion compound Ce3PdIn11 at ambient pressure. Thermodynamic and transport measurements reveal two successive magnetic transitions at T1 = 1.67 K and TN = 1.53 K into antiferromagnetic type of ordered states. Below Tc = 0.42 K the compound enters a superconducting state. The large initial slope of dBc2/dT ≈ - 8.6 T/K indicates that heavy quasiparticles form the Cooper pairs. The origin of the two magnetic transitions and the coexistence of magnetism and superconductivity is briefly discussed in the context of the coexistence of the two inequivalent Ce-sublattices in the unit cell of Ce3PdIn11 with different Kondo couplings to the conduction electrons. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic behavior of the compound DyMn6Ge6 has been studied on single crystals that have been prepared in an In flux. The compound orders antiferromagnetically at about 450K and exhibits very complex magnetic properties in the magnetically ordered state. The evolution of the magnetization in the ordered state as a function of temperature and the magnetization processes has been investigated at various temperatures in fields up to 14T. At 4.2K, where higher magnetic fields were needed, measurements of the magnetization have been carried out in pulsed fields up to around 50T. [Copyright &y& Elsevier]

Abstract: The magnetization of a GdMn6Sn6 single crystal has been measured in static magnetic fields up to 14T as well as in pulsed fields up to 60T. The easy magnetization direction has been confirmed to lie in the basal plane of the hexagonal crystal, the anisotropy within the plane being negligible. However, our data do not corroborate the earlier assertion that GdMn6Sn6 is a collinear ferrimagnet. This disagrees with the observed field dependence of magnetization along the easy direction as well as with the temperature dependence of spontaneous magnetization. A way out of the contradiction is to admit that GdMn6Sn6 has a more complex, non-collinear magnetic structure. [Copyright &y& Elsevier]

Abstract: Crystal structure and magnetic properties are reported for Yb3.50Zn32.1Al1.4 prepared in single-crystalline form. It adopts the SmZn11-type of structure (SG P6/mmm) with lattice parameters a=0.90458(1), c=0.88547(1)nm. The phase composition was analyzed by XRD, chemical and electron microprobe analysis. The ytterbium atoms in this compound are in the non-magnetic 4f 14 state. [Copyright &y& Elsevier]

Many current research efforts in strongly correlated systems focus on the interplay between magnetism and superconductivity. Here we report on coexistence of both cooperative ordered states in recently discovered stoichiometric and fully inversion symmetric heavy fermion compound Ce3PdIn11 at ambient pressure. Thermodynamic and transport measurements reveal two successive magnetic transitions at T1 = 1.67 K and TN = 1.53 K into antiferromagnetic type of ordered states. Below Tc = 0.42 K the compound enters a superconducting state. The large initial slope of dBc2/dT ≈ - 8.6 T/K indicates that heavy quasiparticles form the Cooper pairs. The origin of the two magnetic transitions and the coexistence of magnetism and superconductivity is briefly discussed in the context of the coexistence of the two inequivalent Ce-sublattices in the unit cell of Ce3PdIn11 with different Kondo couplings to the conduction electrons. [ABSTRACT FROM AUTHOR]

The properties of the heavy-fermion superconductor Ce3PtIn11 are investigated by thermodynamic and transport measurements at ambient and under hydrostatic pressure. At ambient pressure the compound exhibits two successive magnetic transitions at T1≃2.2 K and TN≃2 K into antiferromagnetically ordered states and enters into a heavy-fermion superconducting phase below Tc≃0.32 K. The coexistence of long-range magnetic order and superconductivity is discussed in the context of the existence of the two crystallographically inequivalent Ce sites in the unit cell of Ce3PtIn11. The experimental data allow us to construct the pressure-temperature phase diagram. [ABSTRACT FROM AUTHOR]

We present acoustic signatures of the electric quadrupolar degrees of freedom in the honeycomb-layer compound UNi_{4}B. The transverse ultrasonic mode C_{66} shows softening below 30 K both in the paramagnetic phase and antiferromagnetic phases down to ∼0.33  K. Furthermore, we traced magnetic field-temperature phase diagrams up to 30 T and observed a highly anisotropic elastic response within the honeycomb layer. These observations strongly suggest that Γ_{6}(E_{2g}) electric quadrupolar degrees of freedom in localized 5f^{2} (J=4) states are playing an important role in the magnetic toroidal dipole order and magnetic-field-induced phases of UNi_{4}B, and evidence some of the U ions remain in the paramagnetic state even if the system undergoes magnetic toroidal ordering.

Many current research efforts in strongly correlated systems focus on the interplay between magnetism and superconductivity. Here we report on coexistence of both cooperative ordered states in recently discovered stoichiometric and fully inversion symmetric heavy fermion compound Ce3PdIn11 at ambient pressure. Thermodynamic and transport measurements reveal two successive magnetic transitions at T1 = 1.67 K and TN = 1.53 K into antiferromagnetic type of ordered states. Below Tc = 0.42 K the compound enters a superconducting state. The large initial slope of dBc2/dT ≈ - 8.6 T/K indicates that heavy quasiparticles form the Cooper pairs. The origin of the two magnetic transitions and the coexistence of magnetism and superconductivity is briefly discussed in the context of the coexistence of the two inequivalent Ce-sublattices in the unit cell of Ce3PdIn11 with different Kondo couplings to the conduction electrons.

A number of toxic effects of respirable ambient air particles (genotoxic effects, inflammation, oxidative damage) have been attributed to organic compounds bound onto the particle surface. In this study, we analyzed global gene expression changes caused by the extractable organic matters (EOMs) from respirable airborne particles <2.5μm (PM2.5), collected at 3 localities from heavily polluted areas of the Czech Republic and a control locality with low pollution levels, in human lung epithelial A549 cells. Although the sampled localities differed in both extent and sources of air pollution, EOMs did not induce substantially different gene expression profiles. The number of transcripts deregulated in A549 cells treated with the lowest EOM concentration (10μg/ml) ranged from 65 to 85 in 4 sampling localities compared to the number of transcripts deregulated after 30μg/ml and 60μg/ml of EOMs, which ranged from 90 to 109, and from 149 to 452, respectively. We found numerous commonly deregulated genes and pathways related to activation of the aryl hydrocarbon receptor (AhR) and metabolism of xenobiotics and endogenous compounds. We further identified deregulation of expression of the genes involved in pro-inflammatory processes, oxidative stress response and in cancer and developmental pathways, such as TGF-β and Wnt signaling pathways. No cell cycle arrest, DNA repair or pro-apoptotic responses were identified at the transcriptional level after the treatment of A549 cells with EOMs. In conclusion, numerous processes and pathways deregulated in response to EOMs suggest a significant role of activated AhR. Interestingly, we did not observe substantial gene expression changes related to DNA damage response, possibly due to the antagonistic effect of non-genotoxic EOM components. Moreover, a comparison of EOM effects with other available data on modulation of global gene expression suggests possible overlap among the effects of PM2.5, EOMs and various types of AhR agonists., (Copyright © 2014 Elsevier B.V. All rights reserved.)

In this study, we compared the genotoxicity and aryl hydrocarbon receptor (AhR)-dependent transcriptional changes of selected target genes in human lung epithelial A549 cells incubated for 24 h, either with extractable organic matter (EOMs) from airborne particles <2.5 μm (PM2.5) collected at four localities from heavily polluted areas of the Czech Republic or two representative toxic polycyclic aromatic hydrocarbons (PAHs) present in EOMs, benzo[a]pyrene (B[a]P) and benzo[k]fluoranthene (B[k]F). Genotoxic effects were determined using DNA adduct analysis or analysis of expression of selected AhR-related genes involved in bioactivation of PAHs (CYP1A1, CYP1B1) and transcriptional repression (TIPARP). Sampled localities differing in the extent and source of air pollution did not exhibit substantially different genotoxicity. DNA adduct levels induced by three subtoxic EOM concentrations were relatively low (1-5 adducts/10(8) nucleotides), compared to levels induced by similar concentrations of B[a]P, while B[k]F gave very low DNA adduct levels. Here, we compared genotoxicity and gene deregulation induced by complex mixtures containing PAHs with the effects of the comparable concentrations of individual PAHs. Our results suggested inhibition of formation of B[a]P-induced DNA adducts compared to individual B[a]P, probably attributable to competitive inhibition by other non-genotoxic EOM components. In contrast, induction of AhR target genes appeared not to be antagonized by the components of complex mixtures, as induction of CYP1A1, CYP1B1 and TIPARP transcripts reached maximum levels induced by PAHs., (Copyright © 2014 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.)

Background: Recently, we used cell-free assays to demonstrate the toxic effects of complex mixtures of organic extracts from urban air particles (PM2.5) collected in four localities of the Czech Republic (Ostrava-Bartovice, Ostrava-Poruba, Karvina and Trebon) which differed in the extent and sources of air pollution. To obtain further insight into the biological mechanisms of action of the extractable organic matter (EOM) from ambient air particles, human embryonic lung fibroblasts (HEL12469) were treated with the same four EOMs to assess changes in the genome-wide expression profiles compared to DMSO treated controls., Method: For this purpose, HEL cells were incubated with subtoxic EOM concentrations of 10, 30, and 60 μg EOM/ml for 24 hours and global gene expression changes were analyzed using human whole genome microarrays (Illumina). The expression of selected genes was verified by quantitative real-time PCR., Results: Dose-dependent increases in the number of significantly deregulated transcripts as well as dose-response relationships in the levels of individual transcripts were observed. The transcriptomic data did not differ substantially between the localities, suggesting that the air pollution originating mainly from various sources may have similar biological effects. This was further confirmed by the analysis of deregulated pathways and by identification of the most contributing gene modulations. The number of significantly deregulated KEGG pathways, as identified by Goeman's global test, varied, depending on the locality, between 12 to 29. The Metabolism of xenobiotics by cytochrome P450 exhibited the strongest upregulation in all 4 localities and CYP1B1 had a major contribution to the upregulation of this pathway. Other important deregulated pathways in all 4 localities were ABC transporters (involved in the translocation of exogenous and endogenous metabolites across membranes and DNA repair), the Wnt and TGF-β signaling pathways (associated particularly with tumor promotion and progression), Steroid hormone biosynthesis (involved in the endocrine-disrupting activity of chemicals), and Glycerolipid metabolism (pathways involving the lipids with a glycerol backbone including lipid signaling molecules)., Conclusion: The microarray data suggested a prominent role of activation of aryl hydrocarbon receptor-dependent gene expression.