Magnetic interactions in EuTe epitaxial layers and EuTe/PbTe superlattices

The magnetic properties of antiferromagnetic (AFM) EuTe epitaxial layers and short period EuTe/PbTe superlattices (SLs), grown by molecular beam epitaxy on (111) BaF$_2$ substrates, were studied by magnetization and neutron diffraction measurements. Considerable changes of the N\'eel temperature as a function of the EuTe layer thickness as well as of the strain state were found. A mean field model, taking into account the variation of the exchange constants with the strain-induced lattice distortions, and the nearest neighbor environment of a Eu atoms, was developed to explain the observed $T_{\text N}$ changes in wide range of samples. Pronounced interlayer magnetic correlations have been revealed by neutron diffraction in EuTe/PbTe SLs with PbTe spacer thickness up to 60 \AA. The observed diffraction spectra were analyzed, in a kinematical approximation, assuming partial interlayer correlations characterized by an appropriate correlation parameter. The formation of interlayer correlations between the AFM EuTe layers across the nonmagnetic PbTe spacer was explained within a framework of a tight-binding model. In this model, the interlayer coupling stems from the dependence of the total electronic energy of the EuTe/PbTe SL on the spin configurations in adjacent EuTe layers. The influence of the EuTe and PbTe layer thickness fluctuations, inherent in the epitaxial growth process, on magnetic properties and interlayer coupling is discussed.Comment: 17 pages, 19 figures, accepted to PR

How does gender influence the recognition of cardiovascular risk and adherence to self-care recommendations? : a study in polish primary care

Background: Studies have shown a correlation between gender and an ability to change lifestyle to reduce the risk of disease. However, the results of these studies are ambiguous, especially where a healthy lifestyle is concerned. Additionally, health behaviors are strongly modified by culture and the environment. Psychological factors also substantially affect engagement with disease-related lifestyle interventions. This study aimed to examine whether there are differences between men and women in the frequency of health care behavior for the purpose of reducing cardiovascular risk (CVR), as well as cognitive appraisal of this type of risk. We also aimed to identify the psychological predictors of engaging in recommended behavior for reducing the risk of cardiovascular disease after providing information about this risk in men and women. Methods: A total of 134 consecutive eligible patients in a family practice entered a longitudinal study. At initial consultation, the individual’s CVR and associated health burden was examined, and preventive measures were recommended by the physician. Self-care behavior, cognitive appraisal of risk, and coping styles were then assessed using psychological questionnaires. Six months after the initial data collection, the frequency of subjects’ self-care behavior was examined. Results: We found an increase in health care behavior after providing information regarding the rate of CVR in both sexes; this increase was greater for women than for men. Women followed self-care guidelines more often than men, particularly for preventive measures and dietary advice. Women were more inclined to recognize their CVR as a challenge. Coping style, cognitive appraisal, age, level of health behaviors at baseline and CVR values accounted for 48% of the variance in adherence to self-care guidelines in women and it was 52% in men. In women, total risk of CVD values were most important, while in men, cognitive appraisal of harm/loss was most important. Conclusions: Different predictors of acquisition of health behavior are encountered in men and women. Our results suggest that gender-adjusted motivation models influencing the recognition process need to be considered to optimize compliance in patients with CVR

Analysis of the impact of sex and age on the variation in the prevalence of antinuclear autoantibodies in Polish population: a nationwide observational, cross-sectional study

The detection of antinuclear autoantibody (ANA) is dependent on many factors and varies between the populations. The aim of the study was first to assess the prevalence of ANA in the Polish adult population depending on age, sex and the cutoff threshold used for the results obtained. Second, we estimated the occurrence of individual types of ANA-staining patterns. We tested 1731 patient samples using commercially available IIFA using two cutoff thresholds of 1:100 and 1:160. We found ANA in 260 participants (15.0%), but the percentage of positive results strongly depended on the cutoff level. For a cutoff threshold 1:100, the positive population was 19.5% and for the 1:160 cutoff threshold, it was 11.7%. The most prevalent ANA-staining pattern was AC-2 Dense Fine speckled (50%), followed by AC-21 Reticular/AMA (14.38%) ANA more common in women (72%); 64% of ANA-positive patients were over 50 years of age. ANA prevalence in the Polish population is at a level observed in other highly developed countries and is more prevalent in women and elderly individuals. To reduce the number of positive results released, we suggest that Polish laboratories should set 1:160 as the cutoff threshold

Experimental investigations of additional gas extraction inside a cyclone

The paper presents the results of investigations on a cyclone with additional gas extraction. The experiments were performed in the cyclone with a diameter of 0.2 m equipped with a truncated counter-cone situated in the dust bin inlet. The gas stream flowing through the counter-cone was 10 and 20% of the gas supplied to the cyclone. The separation efficiencies and pressure loss were measured. The experiment showed that the extraction of gas by the counter-cone deteriorated the cyclone efficiency and forcing the outflow of gas through the counter-cone requires the use of an additional outlet fan

Diagnostic of the temperature and differential emission measure (DEM) based on <I>Hinode</I>/XRT data

We discuss here various methodologies and an optimal strategy of the temperature and emission measure diagnostics based on Hinode X-Ray Telescope data. As an example of our results we present the determination of the temperature distribution of the X-rays emitting plasma using a filters ratio method and three various methods of the calculation of the differential emission measure (DEM). We have found that all these methods give results similar to the two filters ratio method. Additionally, all methods of the DEM calculation gave similar solutions. We can state that the majority of the pairs of the Hinode filters allows one to derive the temperature and emission measure in the isothermal plasma approximation using standard diagnostics based on the two filters ratio method. In cases of strong flares one can also expect good conformity of the results obtained using a Withbroe – Sylwester, genetic algorithm and least-squares methods of the DEM evaluation

6.7 GHz methanol masers at sites of star formation

We report the results of an unbiased survey for 6.7 GHz methanol maser emission of a ~21 deg2 strip of the Galactic plane carried out with the 32 m Toruń radio telescope. An area at 20°$\le l\le$ 40°, $|b|\le$ 0\fdg52 was surveyed in an equilateral triangular grid with a sensitivity limit of about 1.6 Jy. We detected a total of 100 sources, 26 of which are new detections. All the new sources are of moderate intensity and their peak flux densities have median value of 6.5 Jy, i.e. about half that of previously known sources in the sample. About 80% of maser sources have IR counterpart candidates within a 1\arcmin radius but not all the IRAS counterparts of methanol masers have colours typical of ultracompact HII regions. An excess of masers unassociated with IR sources occurs at 30\degr < l < 35\degr because of incompleteness of IR catalogues due to strong confusion near the tangential region of the spiral arm. Our unbiased survey doubled the number of detections as compared to IRAS-based observations. Within the positional uncertainty of 1\arcmin about one third of the methanol sources have radio continuum counterparts at 5 GHz of a flux density greater than 2.5–10 mJy. The distribution of methanol sources appears to be consistent with a clustered mode of formation of massive stars

Interlayer Coupling in EuS-Based Superlattices Deduced from Neutron Scattering Experiments

The ferromagnetic/diamagnetic semiconductor superlattices, EuS/PbS and EuS/YbSe, were studied by neutron reflectivity. In order to determine the strength of the interlayer coupling, the intensity of the first magnetic Bragg peak vs. applied external magnetic field was measured. Additionally, the in-plane anisotropy and the domain structure were studied by polarized neutron reflectivity. The dependence of the intensity of the antiferromagnetic neutron reflectivity peak vs. magnetic field was simulated using a Stoner-Wohlfarth model. To reproduce the observed spectra it was necessary to take into account the presence of fluctuations of the nonmagnetic layers thickness, by assuming a Gaussian spread of the interlayer coupling constant $J$. For both EuS/PbS and EuS/YbSe superlattices, the best fit was obtained for the directions of the in-plane easy axes, which agree with those determined by polarized neutron reflectivity

Protein adsorption to poly(tetrafluoroethylene) membranes modified with grafted poly(acrylic acid) chains

Protein adsorption to biomaterial surfaces is important for the function of such materials with anchorage-dependent cell adhesion requiring the presence of adsorbed proteins. The current study evaluated five solid surfaces with poly(acrylic acid) (PAA) grafted from the surface of a poly(tetrafluoroethylene) membrane with respect to the adsorption of serum albumin (SA), lactoferrin (Lf), and lysozyme (Lys) from a phosphate buffer and NaCl solution or water for specific combinations. With the use of x-ray photoelectron spectroscopy, the relative amounts and protein layer thickness were evaluated. SA adsorption was governed by ionic repulsive forces and hydrophobic interactions as evidenced from an increase in the protein adsorption at lower pH (6.5 compared to 7.4) and a correlation with surface coverage when water (pH 6.5) was used as the medium. The adsorption of Lf and Lys followed similar trends for all samples. In general, ionic attractive forces dominated and a strong correlation of increasing protein adsorption with the PAA chain length was evident. This study concluded that all surfaces appear suitable for use in biomaterial applications where tissue ingrowth is desired and that the enhanced protein adsorption in a medium with high ionic strength (e.g., biological fluid) correlates with the PAA chain length rather than the surface coverage