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BACKGROUND: It is known that obesity is associated with alterations in blood rheology and venous hemodynamics. Another recent study has confirmed that adipose tissue is actively involved in angiogenesis through secretion of biologically active substances. OBJECTIVE: The aim of this study was to investigate the impact on the venous haemodynamics of the femoral vein on angiogenesis status in morbidly obese patients. METHODS: We studied venous haemodynamics and angiogenesis in a prospective study of obese and non-obese individuals. The venous wall shear stress (WSS) was calculated from the blood viscosity and the shear rate was calculated assuming Newton's law. Angiogenesis was detected using Bio-Plex Pro Human Angiogenesis Multiplex Assays (Bio-Plex 200 Systems). RESULTS: The shear rate (P < 0.000005) and the wall shear stress (P < 0.01) were significantly lower in the obese patients compared with the control subjects. All angiogenesis biomarkers were significantly higher in obese patients compared to the control group. Multivariate analyses identified waist circumference as an independent predictor for PECAM-1 (β = – 0.69, P < 0.0001) and for VEGF (β = – 0.60, P < 0.001); analyses identified WSS as an independent predictor for follistatin (β = – 0.59, P < 0.001), for PECAM-1 (β = – 036, P < 0.05) and for VEGF (β = – 0.42, P < 0.05). For angiopoietin 2 (β = – 0.35, P = 0.064) and HGF (β = – 0.31, P = 0.074), WSS tended to be a significant predictor. CONCLUSIONS: The results indicated that obesity-associated decreases in shear stress of the venous system lead to upregulation of angiogenesis, expressed by increased levels of endogenous positive regulators of angiogenesis. [ABSTRACT FROM AUTHOR]

The Al, Ga, Ti and Zn impurities were studied in high quality single crystal samples of magnetite (Fe3O4). The cases when the valence of the substitution ion differs from that of the original iron ion are of a particular interest. The measurement of nuclear magnetic resonance (NMR) of ^57Fe was chosen as the experimental method for its sensitivity to Fe magnetic and electronic structure and to local ordering in the neighborhood of resonating nuclei. Local electronic structure and hence also the hyperfine interactions are affected by the presence of the substitution and thus resonance frequencies of nuclei in the vicinity of the substitution are shifted due to the modified hyperfine field, therefore satellite signals are observed in the NMR spectra. Temperature dependences of spectra above the Verwey transition were measured in a zero external magnetic field. Subsequently, the dependences of frequencies of main lines and satellite signals in the spectra on temperature were fitted with spin-wave model dependences and compared for different types of the substitution. Furthermore, a mean-field model was applied on the substituted magnetite system and calculated temperature dependences were confronted with the experimental data. The agreement of mean field model with the experimental temperature dependences of satellite resonances is better for those induced by the cationic substitutions at octahedral sites. [ABSTRACT FROM PUBLISHER]

We consider the inclusion of the space of algebraic (regular) maps between real algebraic varieties in the space of all continuous maps. For a certain class of real algebraic varieties, which include real projective spaces, it is well known that the space of real algebraic maps is a dense subset of the space of all continuous maps. Our first result shows that, for this class of varieties, the inclusion is also a homotopy equivalence. After proving this, we restrict the class of varieties to real projective spaces. In this case, the space of algebraic maps has a ‘minimum degree’ filtration by finite-dimensional subspaces and it is natural to expect that the homotopy types of the terms of the filtration approximate closer and closer the homotopy type of the space of continuous mappings as the degree increases. We prove this and compute the lower bounds of this approximation of these spaces. This result can be seen as a generalization of the results of Mostovoy, Vassiliev and others on the topology of the space of real rational maps and the space of real polynomials without n-fold roots. It can also be viewed as a real analogue of Mostovoy's work on the topology of the space of holomorphic maps between complex projective spaces, which generalizes Segal's work on the space of complex rational maps. [ABSTRACT FROM PUBLISHER]

57Fe-enriched Fe4O5 samples were synthesized in a laser-heated diamond anvil cell at a pressure of about 15 GPa and a temperature of about 2000 K. Nuclear forward scattering (NFS) spectra were collected in the range 0-40 GPa and were combined with first-principles calculations to provide insights into the magnetic properties of Fe4O5. NFS spectra show that strong magnetic interactions persist up to 40 GPa and that they are generated by a single magnetic contribution. The hyperfine magnetic field (Bhf) and quadrupole splitting (QS) are in the ranges 51-53 T and 0.40-1.2 mms-1, respectively. The QS shows an intriguing evolution with pressure, with a fast increase from 0.4 to 10.mms-1 between 0 and 10 GPa and a slow increase up to 1.2 mms-1 in the range 10-40 GPa. First-principles calculations suggest an antiferromagnetic ordering for the three sites, and similar magnetic moments in the range ~3.6-3.8 μB/Fe. These values, typical of strongly correlated Fe magnetic systems, are in agreement with the experimental estimated average moment of ~3.8 μB/Fe. The single contribution to the NFS spectrum and the similar calculated magnetic moments suggest that the iron atoms at the three crystallographic sites have similar electronic arrangements. [ABSTRACT FROM AUTHOR]

We present the results of inelastic x-ray scattering for magnetite and analyze the energies and widths of the phonon modes with different symmetries in a broad range of temperature 125 < T < 293 K. The phonon modes with X4 and δ5 symmetries broaden in a nonlinear way with decreasing T when the Verwey transition is approached. It is found that the maxima of phonon widths occur away from high-symmetry points, which suggests the incommensurate character of critical fluctuations. Strong phonon anharmonicity induced by electron-phonon coupling is discovered by a combination of these experimental results with ab initio calculations which take into account local Coulomb interactions at Fe ions. It (i) explains observed anomalous phonon broadening and (ii) demonstrates that the Verwey transition is a cooperative phenomenon which involves a wide spectrum of phonons coupled to the electron charge fluctuations condensing in the low-symmetry phase. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was pineal gland function assessment on the base of daily rhythm study and mean daily melatonin (MEL) concentrations in serum in patients with colorectal carcinoma., Material and Methods: Studies were performed in 12 women at the age of 63.17+/-5.90 years and 21 men aged 58.95+/-11.32 years with large intestine adenocarcinoma. The control group consisted of 28 healthy volunteers at comparable age. During the circadian study blood samples for the measurement of melatonin (MEL) were collected every 4 hours during 12 h. MEL concentrations were assessed with the use of RIA methods. Statistical analysis of circadian rhythms of MEL was carried out with the use of cosinor method according to Halberg., Results: Existence of daily rhythm of MEL secretion was shown in all studied groups. A significant decrease of amplitude of rhythm and secretion of MEL at nocturnal hours in comparison with the control group was shown in the group of women with large intestine carcinoma. A significant decrease of mesor value and amplitude of MEL rhythm as a consequence of decrease of MEL secretion at nocturnal and morning hours was observed in the group of ill men., Conclusions: Decrease in melatonin circadian rhythm amplitude as a consequence of its lowered nocturnal secretion occurred in all patients with colorectal carcinoma. Abnormalities in daily rhythm of melatonin secretion were more intensified in men with large intestine carcinoma, which leads to suppression of mean daily hormone concentration.