Search results

We present the extension of time-resolved optical pump/x-ray absorption spectroscopy (XAS) probe experiments towards data collection at MHz repetition rates. The use of a high-power picosecond laser operating at an integer fraction of the repetition rate of the storage ring allows exploitation of up to two orders of magnitude more x-ray photons than in previous schemes based on the use of kHz lase

We review our recent studies of excited state structures and dynamics of chemical and biological systems with pico- and femtosecond X-ray absorption spectroscopy in the liquid phase.

We present ultrafast x-ray emission studies of photoexcited aqueous iron tris-bipyridine with 70 ps temporal resolution to monitor the spin state changes in this spin-crossover complex.

Understanding the initial steps during ultrafast molecular reactions involving large spin state changes is a vital goal in structural dynamics research. These involve knowledge of the geometric structure of the system. Ultrafast X-ray absorption spectroscopy with 50-100 picosecond time resolution establishes the geometric structure of the short-lived (τ = 0:6 ns) high spin state. Here we focus on

(Figure Presented) Ultrafast spin probe: A short-lived transient species of light-excited [Fe(bpy) 3 ] 2+ (bpy = 2,2′-bipyridine) shows geometry variations that correspond to excitation to a high-spin state, in which the spin momentum of Fe" has now been directly determined to be S = 2 by spin-sensitive ultrafast X-ray emission spectroscopy.

The L3 X-ray absorption spectrum of aqueous iodide is reported, and its EXAFS is compared to theoretical spectra reconstructed from the radial distribution function of the iodide hydration obtained from classical, hybrid Quantum Mechanics Molecular Mechanics, (QM/MM) and full quantum (density functional theory, DFT) molecular dynamics simulations. Since EXAFS is mainly sensitive to short distances

Ultrafast X-ray absorption spectroscopy is a powerful tool to observe electronic and geometric structures of short-lived reaction intermediates. The ab initiofeff9 code is applied to simulate the Pt L3-edge XANES spectrum of the photocatalytic diplatinum molecule [Pt2(P2O5H2)4]4− and the photo-induced changes that occur therein. The spectra are interpreted within a XAFS-like scattering theoretical

A dietary survey was performed during a large screening study in Sweden among 13-year-old adolescents. The aim was to study how the intake of food groups was affected by a screening-detected diagnosis of coeliac disease (CD) and its gluten-free (GF) treatment. Food intake was reported using a FFQ, and intake reported by the adolescents who were diagnosed with CD was compared with the intake of two

Background Exposure to cigarette smoke (CS) is associated with increased risk of pneumococcal infection. The mechanism for this association is unknown. We recently reported that the particulate matter from urban air simulates platelet-activating factor receptor (PAFR)-dependent adhesion of pneumococci to airway cells. We therefore sought to determine whether CS stimulates pneumococcal adhesion to

Stem cell-based approaches have received much hype as potential treatments for neurodegenerative disorders. Indeed, transplantation of stem cells or their derivatives in animal models of neurodegenerative diseases can improve function by replacing the lost neurons and glial cells and by mediating remyelination, trophic actions, and modulation of inflammation. Endogenous neural stem cells are also

We present a method to compute, quickly and efficiently, the mutual information achieved by an independent identically distributed (IID) complex Gaussian signal on a block Rayleigh-faded channel without side information at the receiver. The method accommodates both scalar and multiple-input multiple-output (MIMO) settings. Operationally, this mutual information represents the highest spectral effi

The Dalitz decay eta -> e(+) e(-) gamma has been measured in the gamma p -> eta p reaction with the Crystal Ball and TAPS multiphoton spectrometers, together with the photon-tagging facility at the Mainz Microtron MAMI. The experimental statistic used in this work is one order of magnitude greater than in any previous measurement of eta -> e(+) e(-) gamma. The value obtained for the slope paramete

Background: Obesity, type 2 diabetes and atrial fibrillation (AF) are closely associated, but the underlying mechanisms are not fully understood. We aimed to explore associations between body mass index (BMI) or weight change with risk of AF in patients with type 2 diabetes. Methods: A total of 7,169 participations with newly diagnosed type 2 diabetes were stratified according to baseline BMI, and

We use a recently developed parametrization to estimate the regional particle field in the summer time troposphere over Scandinavia that would result if the forest were the only source of particles. The calculated field is compared with available observational data. It is concluded that the needle leaf forest above 58 degrees N alone is capable of producing aerosol mass concentrations correspondin

Granular GaAs:(Mn,Ga)As films were prepared by annealing at 500 degrees C under ambient and enhanced hydrostatic pressure (1.1 GPa), of Ga1-xMnxAs/GaAs layers (x = 0.025, 0.03, 0.04, 0.05 and 0.063) grown at 230 degrees C by molecular beam epitaxy method. Distinct influence of enhanced hydrostatic pressure applied during sample annealing on strain state of inclusions was found. An increase of latt

Human carbonyl reductase 1 (CBR1), that is one of the enzymes responsible for the reduced efficiency of treatments by the antineoplastic agents anthracyclines, was functionally expressed in Saccharomyces cerevisiae. CBR1 was purified and kinetically characterised using daunorubicin as substrate. CBR1-catalysed reduction of daunorubicin followed an apparent Michaelis-Menten kinetics with K-M = 85.2

Context: Rapid cycling is a severe form of bipolar disorder with an increased rate of episodes that is particularly treatment-responsive to chronotherapy and stable sleep-wake cycles. We hypothesized that the P2RX7 gene would be affected by sleep deprivation and be implicated in rapid cycling. Objectives: To assess whether P2RX7 expression is affected by total sleep deprivation and if variation in

OBJECTIVE- Some individuals with normal glucose tolerance (NGT) exhibit a 1-h excursion of plasma glucose during oral glucose tolerance testing as high as that of individuals with impaired glucose tolerance (IGT). The aim of this study was to characterize their metabolic phenotype. RESEARCH DESIGN AND METHODS- A total of 1,205 healthy volunteers (aged 29-61 years) underwent assessment of 1) oral g