1,597 research outputs found
Neue Entwicklungen in puncto Sammelklagen - in Deutschland, in den Niederlanden und an der Grenze
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Elevated Soluble Fms-Like Tyrosine Kinase-1 and Placental-Like Growth Factor Levels Are Associated With Development and Mortality Risk in Heart Failure
Background—Vascular endothelial dysfunction may play an important role in the progression of heart failure (HF). We hypothesize that elevated levels of vascular markers, placental-like growth factor, and soluble Fms-like tyrosine kinase-1 (sFlt-1) are associated with adverse outcomes in patients with HF. We also assessed possible triggers of sFlt-1 elevation in animal HF models. Methods and Results—We measured plasma placental-like growth factor and sFlt-1 in 791 HF patients undergoing elective coronary angiogram. Median (interquartile range) placental-like growth factor and sFlt-1 levels were 24 (20–29) and 382 (277–953) pg/mL, respectively. After 5 years of follow-up, and after using receiver operator characteristic curves to determine optimal cutoffs, high levels of sFlt-1 (≥280 pg/mL; adjusted hazard ratio, 1.47; 95% confidence interval, 1.03–2.09; P=0.035) but not placental-like growth factor (≥25 pg/mL; adjusted hazard ratio, 1.26; 95% confidence interval, 0.94–1.71, P=0.12) were associated with adverse cardiovascular outcomes. In addition, significant elevation of sFlt-1 levels was observed in left anterior descending artery ligation and transverse aortic constriction HF mouse models after 4 and 8 weeks of follow-up, suggesting vascular stress and ischemia as triggers for sFlt-1 elevation in HF. Conclusions—Circulating sFlt-1 is generated as a result of myocardial injury and subsequent HF development. Elevated levels of sFlt-1 are associated with adverse outcomes in stable patients with HF
Electromagnetic effects in the surface enhanced Raman scattering from a molecule at a liquid Hg surface
In a previous publication the image enhancement effect and the enhanced radiation due to near field excitation of surface roughness were calculated for a finite-size molecule above a metal described by a nonlocal dielectric relation [Phys. Rev. Letters 44 (1980) 1774]. When applied to a roughened Ag surface these calculations led to a predicted Surface Enhanced Raman Scattering (SERS) gain of [approximate]103 due to each effect, yielding an overall gain [approximate]106, in agreement with experiment. Here these calculations are extended to the case of a liquid Hg surface, the roughness corresponding to thermally excited ripplons. The SERS gain due to image enhancement is reduced to [approximate]10, due primarily to the [approximate]24 times greater electron scattering rate in Hg over that in Ag. The roughness gain is reduced to [approximate]2 at room temperature, due to the difference between the ripplon spectrum and that of the boss-like surface structures assumed for the solid surface. The predicted overall SERS gain for Hg is [approximate]20, far less than reported in recent observations [R. Naanan et al., J. Phys. Chem. 84 (1980) 2692]. The discrepancy raises serious questions about the electromagnetic explanations of SERS.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24261/1/0000524.pd
Reduction of the Three Dimensional Schrodinger Equation for Multilayered Films
In this paper, we present a method for reducing the three dimensional
Schrodinger equation to study confined metallic states, such as quantum well
states, in a multilayer film geometry. While discussing some approximations
that are employed when dealing with the three dimensionality of the problem, we
derive a one dimensional equation suitable for studying such states using an
envelope function approach. Some applications to the Cu/Co multilayer system
with regard to spin tunneling/rotations and angle resolved photoemission are
discussed.Comment: 14 pages, 1 figur
Baffin Island Expedition, 1953: A Preliminary Field Report
Contains description and brief summaries of results of the second Baffin Island Expedition of the Arctic Institute of North America, May-Sept. 1953. The 13-man party carried out a program in the Penny Highland region of Cumberland Peninsula, centering on Pangnirtung Pass. Glaciological work on the Penny Icecap and Highway Glacier included studies of glacier physics, seismic work, and meteorological observations on bedrock geology and structure are given. Corrie formation and the geomorphology of Pangnirtung Pass were studied. Specimens of local fauna were collected and biological studies of some species were made. Comparisons of the vegetation of Penny Highland and East and North Greenland were made through extensive plant collections. Eight peaks were climbed and their altitudes determined. A list of 17 new names approved by the Canadian Board on Geographical Names is appended
Energy landscape, two-level systems and entropy barriers in Lennard-Jones clusters
We develop an efficient numerical algorithm for the identification of a large
number of saddle points of the potential energy function of Lennard- Jones
clusters. Knowledge of the saddle points allows us to find many thousand
adjacent minima of clusters containing up to 80 argon atoms and to locate many
pairs of minima with the right characteristics to form two-level systems (TLS).
The true TLS are singled out by calculating the ground-state tunneling
splitting. The entropic contribution to all barriers is evaluated and
discussed.Comment: 4 pages, RevTex, 2 PostScript figure
Raman scattering studies of spin, charge, and lattice dynamics in Ca_{2-x}Sr_{x}RuO_{4} (0 =< x < 0.2)
We use Raman scattering to study spin, charge, and lattice dynamics in
various phases of Ca_{2-x}Sr_{x}RuO_{4}. With increasing substitution of Ca by
Sr in the range 0 =< x < 0.2, we observe (1) evidence for an increase of the
electron-phonon interaction strength, (2) an increased temperature-dependence
of the two-magnon energy and linewidth in the antiferromagnetic insulating
phase, and (3) evidence for charge gap development, and hysteresis associated
with the structural phase change, both of which are indicative of a first-order
metal-insulator transition (T_{MI}) and a coexistence of metallic and
insulating components for T < T_{MI}
First-principles study of the ferroelastic phase transition in CaCl_2
First-principles density-functional calculations within the local-density
approximation and the pseudopotential approach are used to study and
characterize the ferroelastic phase transition in calcium chloride (CaCl_2). In
accord with experiment, the energy map of CaCl_2 has the typical features of a
pseudoproper ferroelastic with an optical instability as ultimate origin of the
phase transition. This unstable optic mode is close to a pure rigid unit mode
of the framework of chlorine atoms and has a negative Gruneisen parameter. The
ab-initio ground state agrees fairly well with the experimental low temperature
structure extrapolated at 0K. The calculated energy map around the ground state
is interpreted as an extrapolated Landau free-energy and is successfully used
to explain some of the observed thermal properties. Higher-order anharmonic
couplings between the strain and the unstable optic mode, proposed in previous
literature as important terms to explain the soft-phonon temperature behavior,
are shown to be irrelevant for this purpose. The LAPW method is shown to
reproduce the plane-wave results in CaCl_2 within the precision of the
calculations, and is used to analyze the relative stability of different phases
in CaCl_2 and the chemically similar compound SrCl_2.Comment: 9 pages, 6 figures, uses RevTeX
Fresnel polarisation of infra-red radiation by elemental bismuth
We revisit the classical problem of electromagnetic wave refraction from a lossless dielectric to a lossy conductor, where both media are considered to be non-magnetic, linear, isotropic and homogeneous. We derive the Fresnel coefficients of the system and the Poynting vectors at the interface, in order to compute the reflectance and transmittance of the system. We use a particular parametrisation of the referred Fresnel coefficients so as to make a connection with the ones obtained for refraction by an interface between two lossless media. This analysis allows the discussion of an actual application, namely the Fresnel polarisation of infra-red radiation by elemental bismuth, based on the concept of pseudo Brewster’s angle.We acknowledge helpful discussions with M. Vasilevskiy, P. Alpuim, J. Caridad and B. Figueiredo. The authors thank the European Structural and Investment Funds in the FEDER component, through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020) [under the Project GNESIS -Graphenest's New Engineered System and its Implementation Solutions; Funding Reference: POCI-01-0247-FEDER-033566], European Regional Development Fund. This work was also supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019
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