399 research outputs found
Temperature-induced sign change of the magnetic interlayer coupling in Ni/Ni25Mn75/Ni trilayers on Cu3Au(001)
We investigated the magnetic interlayer coupling between two ferromagnetic
(FM) Ni layers through an antiferromagnetic (AFM) Ni 25Mn75 layer and the
influence of this coupling on the exchange bias phenomenon. The interlayer
coupling energy of an epitaxial trilayer of 14 atomic monolayers (ML) Ni/45 ML
Ni 25Mn75/16 ML Ni on Cu3Au(001) was extracted from minor-loop magnetization
measurements using in-situ magneto-optical Kerr effect. The interlayer
coupling changes from ferromagnetic to antiferromagnetic when the temperature
is increased above 300 K. This sign change is interpreted as the result of the
competition between an antiparallel Ruderman-Kittel-Kasuya-Yosida (RKKY)-type
interlayer coupling, which dominates at high temperature, and a stronger
direct exchange coupling across the AFM layer, which is present only below the
Néel temperature of the AFM layer
Iron porphyrin molecules on Cu(001): Influence of adlayers and ligands on the magnetic properties
The structural and magnetic properties of Fe octaethylporphyrin (OEP)
molecules on Cu(001) have been investigated by means of density functional
theory (DFT) methods and X-ray absorption spectroscopy. The molecules have been
adsorbed on the bare metal surface and on an oxygen-covered surface, which
shows a reconstruction. In order to allow
for a direct comparison between magnetic moments obtained from sum-rule
analysis and DFT we calculate the dipolar term , which is also
important in view of the magnetic anisotropy of the molecule. The measured
X-ray magnetic circular dichroism shows a strong dependence on the photon
incidence angle, which we could relate to a huge value of , e.g. on
Cu(001) amounts to -2.07\,\mbo{} for normal incidence leading to a
reduction of the effective spin moment . Calculations have also
been performed to study the influence of possible ligands such as Cl and O
atoms on the magnetic properties of the molecule and the interaction between
molecule and surface, because the experimental spectra display a clear
dependence on the ligand, which is used to stabilize the molecule in the gas
phase. Both types of ligands weaken the hybridization between surface and
porphyrin molecule and change the magnetic spin state of the molecule, but the
changes in the X-ray absorption are clearly related to residual Cl ligands.Comment: 17 figures, full articl
Variations temporelles des teneurs en polluants organiques lors d'évènements pluvieux dans un milieu récepteur urbain
Spin polarization of the L-gap surface states on Au(111)
The electron spin polarization (ESP) of the L-gap surface states on Au(111)
is investigated theoretically by means of first-principles electronic-structure
and photoemission calculations. The surface states show a large spin-orbit
induced in-plane ESP which is perpendicular to the in-plane wavevector, in
close analogy to a two-dimensional electron gas with Rashba spin-orbit
interaction. The surface corrugation leads to a small ESP component normal to
the surface, being not reported so far. The surface-states ESP can be probed
qualitatively and quantitatively by spin- and angle-resolved photoelectron
spectroscopy, provided that the initial-state ESP is retained in the
photoemission process and not obscured by spin-orbit induced polarization
effects. Relativistic photoemission calculations provide detailed information
on what photoemission set-ups allow to conclude from the photoelectron ESP on
that of the surface states.Comment: 22 pages with 8 figure
Prevalence and risk factors associated with chronic kidney disease in Nepal: evidence from a nationally representative population-based cross-sectional study.
OBJECTIVE: This study aimed to determine population-based prevalence of chronic kidney disease (CKD) and its associated factors in Nepal. STUDY DESIGN: The study was a nationwide population-based cross-sectional study. SETTING AND PARTICIPANTS: Cross-sectional survey conducted in a nationally representative sample of 12 109 Nepalese adult from 2016 to 2018 on selected chronic non-communicable diseases was examined. Multistage cluster sampling with a mix of probability proportionate to size and systematic random sampling was used for the selection of individuals aged 20 years and above. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary outcome in this study was population-based prevalence of CKD in Nepal. A participant was considered to have CKD if the urine albumin-to-creatinine ratio was greater than or equal to 30 mg/g and/or estimated glomerular filtration rate is less than 60 mL/min/1.73 m2 at baseline and in follow-up using modification of diet in renal disease study equations. The secondary outcome measure was factors associated with CKD in Nepal. The covariate adjusted association of risk factors and CKD was calculated using multivariable binary logistic regression. RESULTS: The overall prevalence of CKD in Nepal was 6.0% (95% CI 5.5 to 6.6). Factors independently associated with CKD included older age (adjusted OR (AOR) 2.6, 95% CI 1.9 to 3.6), Dalit caste (AOR 1.6, 95% CI 1.1 to 2.3), hypertension (AOR 2.4, 95% CI 2.0 to 3.0), diabetes mellitus (AOR 3.2, 95% CI 2.5 to 4.1), raised total cholesterol (AOR 1.3, 95% CI 1.0 to 1.6) and increased waist-to-hip ratio (AOR 1.6, 95% CI 1.2 to 2.3). CONCLUSION: This nationally representative study shows that the prevalence of CKD in the adult population of Nepal is substantial, and it is independently associated with several cardiometabolic traits. These findings warrant longitudinal studies to identify the causes of CKD in Nepal and effective strategies to prevent it
A report of Streptococcus pneumoniae serotype 6D in Europe
Serotype 6D of Streptococcus pneumoniae has been reported in Asia and the Fijian islands among nasopharyngeal carriage isolates. We now report a 6D isolate from a Finnish adult with invasive pneumococcal disease. Interestingly, the Finnish isolate and Asian isolate capsule gene loci are almost identical
Heat in Germany: Health risks and preventive measures
BACKGROUND: Climate change has already led to a significant temperature increase in Germany. The average temperature in the past decade was approximately 2°C above the pre-industrial level and eight of the ten hottest summers since the beginning of systematic weather records in 1881 were recorded in the last 30 years. METHODS: Based on a selective literature search and authors' own results, the article summarises the current state of knowledge on heat and its health impacts for Germany, addresses adaptation measures, and gives an outlook on implementation and research questions. RESULTS: Heat can aggravate pre-existing conditions such as diseases of the cardiovascular system, the respiratory tract, or the kidneys and trigger potentially harmful side effects for numerous medications. A significant increase in mortality is regularly observed during heat events. Previous approaches to mitigate the health impact of high temperatures include, for example, the heat alerts of the German Meteorological Service and recommendations for the preparation of heat-health action plans. CONCLUSIONS: Evidence on health impacts of heat and awareness of the need for heat-related health protection have grown in recent years, but there is still a need for further action and research
Left ventricular geometric patterns and adaptations to hemodynamics are similar in elderly men and women
<p>Abstract</p> <p>Background</p> <p>Common conditions such as obesity and hypertension result in hemodynamic alterations that will induce remodeling of the left ventricle (LV). However, differences between the genders in the relationship of hemodynamics to LV geometry are not well known.</p> <p>The present study aims to investigate differences between the genders in this respect, in a sample of elderly persons.</p> <p>Methods</p> <p>Echocardiography and Doppler was performed in a population-based sample aged 70 - The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (n = 922).</p> <p>Hemodynamic patterns obtained by echocardiography and Doppler were evaluated in relation to four LV geometric groups (normal, concentric remodeling, eccentric hypertrophy and concentric hypertrophy).</p> <p>Results</p> <p>No significant difference between the genders was observed regarding the prevalence of the LV geometric groups.</p> <p>Mean values of most evaluated echocardiography and Doppler variables differed between men and women, such as LA, IVS, LVEDD and IVRT, but the relationship of hemodynamic variables to LV geometric groups did not differ between the genders.</p> <p>Conclusions</p> <p>Although mean values of many echocardiographic variables differed between men and women, the LV geometric adaptations to a given hemodynamic load appear similar in both genders.</p
X-ray-Induced Reversible Switching of an Azobenzene Derivative Adsorbed on Bi(111)
We report on the adsorption of a submonolayer of di-m-cyanoazobenzene (DMC) on
Bi(111) and on the reversible switching of these molecules induced by resonant
X-ray illumination. DMC adsorbs in at least two configurations, the flat trans
and the nonflat cis isomer. We find that in 0.8 monolayers at least 26% of the
molecules change their configuration at 110 K by excitation of the N1s → LUMO
transition at the azo group, and by a thermally induced back reaction at 120
K. Nonresonant excitation with X-ray light does not induce any reversible
changes
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