A New Quasi-one-dimensional Spin Chain and Its Critical Behavior

The critical exponent, power of critical behavior near phase transition and critical point, depends on global properties such as the space dimensionality, the symmetry of the order parameter, and the range of interaction, rather than microscopic details. For example, there have been plenty of investigation about the critical phenomena associated with space and spin dimensions of the quantum magnet. Here we introduce a new quasi-one-dimensional spin chain compound NiTe2O5. Performing a comprehensive study of the structure and magnetic properties, we found that NiTe2O5 undergoes intriguing long-range antiferromagnetic order at TN = 30.5 K. Below the Neel temperature, longitudinal component of Ni2+ spin-1 along the chain are ferromagnetically ordered but transverse component has alternating ferromagnetic-antiferromagnetic coupling. In addition, temperature evolution of the antiferromagnetic order parameter accompanies an unconventional critical behavior. In this talk, we present and discuss the physical properties and the nature of the phase transition of NiTe2O5

Effects from a 90-day inhalation toxicity study with cerium oxide and barium sulfate nanoparticles in rats

Background: Nanomaterials like cerium oxide and barium sulfate are frequently processed in industrial and consumer products and exposure of humans and other organisms is likely. Generally less information is given on health effects and toxicity, especially regarding long-term exposure to low nanoparticle doses. Since inhalation is still the major route of uptake the present study focused on pulmonary effects of CeO2NM-212 (0.1, 0.3, 1.0, 3.0 mg/m(3)) and BaSO4NM-220 nanoparticles (50.0 mg/m(3)) in a 90-day exposure setup. To define particle-related effects and potential mechanisms of action, observations in histopathology, bronchoalveolar lavage and immunohistochemistry were linked to pulmonary deposition and clearance rates. This further allows evaluation of potential overload related effects. Results: Lung burden values increased with increasing nanoparticle dose levels and ongoing exposure. At higher doses, cerium clearance was impaired, suggesting lung overload. Barium elimination was extremely rapid and without any signs of overload. Bronchoalveolar lavage fluid analysis and histopathology revealed lung tissue inflammation with increasing severity and post-exposure persistency for CeO2. Also, marker levels for genotoxicity and cell proliferation were significantly increased. BaSO4 showed less inflammation or persistency of effects and particularly affected the nasal cavity. Conclusion: CeO2 nanoparticles penetrate the alveolar space and affect the respiratory tract after inhalation mainly in terms of inflammation. Effects at low dose levels and post-exposure persistency suggest potential long-term effects and a notable relevance for human health. The generated data might be useful to improve nanoparticle risk assessment and threshold value generation. Mechanistic investigations at conditions of non-overload and absent inflammation should be further investigated in future studies