Traveling-stripe forcing generates hexagonal patterns

We study the response of Turing stripe patterns to a simple spatiotemporal forcing. This forcing has the form of a traveling wave and is spatially resonant with the characteristic Turing wavelength. Experiments conducted with the photosensitive chlorine dioxide-iodine-malonic acid reaction reveal a striking symmetry-breaking phenomenon of the intrinsic striped patterns giving rise to hexagonal lattices for intermediate values of the forcing velocity. The phenomenon is understood in the framework of the corresponding amplitude equations, which unveils a complex scenario of dynamical behaviors.     

Experimental detection of multipartite entanglement using witness operators

We present the experimental detection of genuine multipartite entanglement using entanglement witness operators. To this aim, we introduce a canonical way of constructing and decomposing witness operators so that they can be directly implemented with present technology. We apply this method to three- and four-qubit entangled states of polarized photons, giving experimental evidence that the considered states contain true multipartite entanglement.     

Q2 evolution of the neutron spin structure moments using a 3He target

We have measured the spin structure functions g(1) and g(2) of 3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a polarized 3He target at a 15.5 degrees scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q2 evolution of Gamma(1)(Q2)= integral (1)(0)g(1)(x,Q2)dx, Gamma(2)(Q2)= integral (1)(0)g(2)(x,Q2)dx, and d(2)(Q2)= integral (1)(0)x(2)[2g(1)(x,Q2)+3g(2)(x,Q2)]dx for the neutron in the range 0.1< or =Q2< or =0.9 GeV2 with good precision. Gamma(1)(Q2) displays a smooth variation from high to low Q2. The Burkhardt-Cottingham sum rule holds within uncertainties and d(2) is nonzero over the measured range.     

Homonuclear Hartmann-Hahn transfer with reduced relaxation losses by use of the MOCCA-XY16 multiple pulse sequence

Homonuclear Hartmann-Hahn transfer is one of the most important building blocks in modern high-resolution NMR. It constitutes a very efficient transfer element for the assignment of proteins, nucleic acids, and oligosaccharides. Nevertheless, in macromolecules exceeding approximately 10 kDa TOCSY-experiments can show decreasing sensitivity due to fast transverse relaxation processes that are active during the mixing periods. In this article we propose the MOCCA-XY16 multiple pulse sequence, originally developed for efficient TOCSY transfer through residual dipolar couplings, as a homonuclear Hartmann-Hahn sequence with improved relaxation properties. A theoretical analysis of the coherence transfer via scalar couplings and its relaxation behavior as well as experimental transfer curves for MOCCA-XY16 relative to the well-characterized DIPSI-2 multiple pulse sequence are given.     

Determining the relative sign and size of scalar and residual dipolar couplings in homonuclear two-spin systems

Based on the sign and amplitude of TOCSY transfer functions, it is possible to determine the relative sign and size of scalar and residual dipolar couplings in homonuclear spin systems consisting of two spins 1/2. The efficiency of different mixing sequences and different transfer functions is examined both theoretically and experimentally.     

Rapid and simple determination of doxycycline in serum by high-performance liquid chromatography. Application to particulate drug delivery systems

A simple, rapid and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method for the measurement of doxycycline concentrations in both drug delivery systems (DDS) and serum extracted from mice after intraperitoneal (free drug) and intravenous (doxycycline administered in DDS) administration, has been developed. For the analysis of doxycycline in DDS, a known amount of particles was dissolved in chloroform and, after precipitating the polymer with methanol, the drug was assessed in the supernatant. For doxycycline quantification in microsamples of serum, proteins were precipitated with acetonitrile before chromatographic analysis. After centrifugation, the supernatant was mixed with a mixture of methanol and acetic acid (1:1) for analysis. The samples were chromatographed on a narrow-bore C18 column (Alltech Alltima 150 mm x 2.1 mm) using a mobile phase with 55% acetic acid (5%), 25% acetonitrile and 20% methanol. Doxycycline was detected 347 nm and the run time was 10 min. Linearity was confirmed in the concentration range 0.4-80 microg/ml for doxycycline quantification in serum and from 1 to 800 microg/ml for doxycycline extracted from DDS samples.     

Energieverlust und Reichweite von α-Teilchen in Bor im Energiebereich von 0,2 bis 5,3 MeV

With a scintillation spectrometer the air equivalent of boron for α-particles has been measured as a function of the energy. The boron foils (50?120 μg·cm^?2) were evaporated onto thin mica. The α-particle energy was set to between 0.2 and 5.3 MeV by letting the particles of a²¹⁰Po-α-source pass through air. With known data for the energy loss in air the range and stopping power in boron have been determined. The error of each measured datum is about 2%.     

Adsorption of krypton on the basal plane of graphite: LEED and Auger measurements

The adsorption of krypton on (0001) graphite has been studied by LEED and Auger. Stepwise isotherms are observed and thermodynamic quantities such as the latent heat of two dimensional adsorption and the binding energy of a krypton atom are determined. The mean free path of electrons in krypton is measured. The LEED pattern of the krypton layer shows a √3 × √3 superstructure. Some vibrational properties are examined by LEED and possible implications of the experimental findings are discussed. The potentials and limitations of the techniques used in the present work are critically examined with respect to other techniques.