Magnetism of single-crystalline Fe nanostructures.

The quantitative investigation of magnetic nanostructures by means of ferromagnetic resonance is demonstrated for single-crystalline iron nanostructures. It is shown that the single-crystalline nature leads to effects not being present in polycrystalline ones and helps to quantitatively interpret the results. First a method is presented that enables one to fabricate epitaxial Fe nanowires starting from a thin film of Fe grown under ultrahigh vacuum conditions on GaAs (110). The system allows, due to the combination of cubic and twofold magnetic anisotropy, to prepare wires whose easy axis in remanence is oriented perpendicular to the wires axis. This unique feature is only achievable in epitaxial systems. Furthermore, nearly perfect Fe nanocubes with 13.6 nm edge length prepared by wet-chemical methods are studied. While the shell of the particles is composed of either Fe3O4 or gamma-Fe2O3, the core consists of metallic Fe. Oxygen and hydrogen plasma are used to remove the ligand system and the oxide shell. The single-crystalline nature of the cubes enables one to quantitatively determine the magnetic properties of the individual particle by means of ferromagnetic resonance measurements on an ensemble together with a model based on the Landau-Lifshitz equation. The measurements reveal a magneto-crystalline anisotropy of K4 = 4.8. 10(4) J/m3 being equal to bulk value and a saturation magnetization which is reduced to M(5K) = (1.2 +/- 0.12). 10(6) A/m (70% of bulk value). The effective damping parameter alpha = 0.03 is increased by one order of magnitude with respect to bulk Fe, showing that magnetic damping in nanostructures differs from the bulk.

Inhomogeneous alloying in FePt nanoparticles as a reason for reduced magnetic moments.

The reduced magnetic moments of oxide-free FePt nanoparticles are discussed in terms of lattice expansion and local deviation from the averaged composition. By analyses of the extended x-ray absorption fine structure of FePt nanoparticles and bulk material measured both at the Fe K and Pt L(3) absorption edge, the composition within the single nanoparticles is found to be inhomogeneous, i.e. Pt is in a Pt-rich environment and, consequently, Fe is in an Fe-rich environment. The standard Fourier transformation-based analysis is complemented by a wavelet transformation method clearly visualizing the difference in the local composition. The dependence of the magnetic properties, i.e. the element-specific magnetic moments on the composition in chemically disordered Fe(x)Pt(1-x) alloys, is studied by fully relativistic SPR-KKR band structure calculations supported by experimental results determined from the x-ray magnetic circular dichroism of 50 nm thick films and bulk material.

[Cyclopheron pretreatment in opisthorchiasis management in patients with viral hepatitis C].

AIM: To assess efficacy of cyclopheron (Polysan production) as opisthorchiasis pretreatment in patients with chronic viral hepatitis C (CHC). MATERIAL AND METHODS: Fifteen CHC patients received cyclopheron by 6 month scheme before dehelminthization. The effect was evaluated by dynamics of clinical symptoms, results of functional hepatic tests, levels of autoantibodies to antigens of native and denaturated DNA, CIC and lactoferrin. Fourteen control patients did not receive pretreatment with cyclopheron. RESULTS: The study group patients exhibited a relief of asthenovegetative and pain syndromes, aminotranspherases lowered to normal in 11 patients, minimal activity of cytolytic syndrome--in 4 patients. Lactoferrin normalized in all the patients, coefficient of autoantibodies to antigens of native and denaturated DNA fell two-fold. No significant improvement in the clinical and laboratory picture was seen in the controls. CONCLUSION: Cyclopheron in patients with CHC combination with chronic opisthorchiasis is recommended as pretreatment before dehelminthization.

[Connections between the mast cell system of a focus of inflammation and the zona fasciculata of the adrenal cortex]. / O sviazakh sistemy tuchnykh kletok ochaga vospaleniia s puchkovoi zonoi kory nadpochechnikov.

At aseptic inflammation developing around a solid foreign body and proceeding both under common conditions and on the background of disturbed inactivation of free amines as a result of monoaminoxidase blockade with vetrasin or devastation of amine tissue depots with reserpine it has been stated that indices of the adrenal cortex activity (hyperemia, contents of ascorbic acid and corticoids) and those of the mast cells system in the inflammatory focus (amount of the cells, their size, contents of glycosaminoglycans, RNA, tryptophan and histidine) are subjected to certain fluctuations during inflammation. Increasing activity of the adrenal cortex fascicular zone and renewal of the mast cell population in the inflammatory focus are directly proportional to the degree of a disturbed deposition of free amines in the organism. Certain positive correlations prevail in cooperation of the adrenal cortex activity, decomposition rate of large (mature) mast cells and migration into the inflammatory focus of small (immature) forms of these cells.