Evidence for Kosterlitz-Thouless behavior in the disordered and frustrated two-dimensionalXY-model

We present Monte-Carlo results providing strong evidence for a non-universal Kosterlitz-Thouless transition in the disordered and frustrated two-dimensionalXY-model for various magnetic fields, giving rise to frustration.     

Low-lying (K π = 0+) states of gadolinium isotopes

The sd-interacting boson approximation (sd-IBA) and the df-interacting boson approximation (df-IBA) can be related to each other and the states of the interacting boson approximation model can be identified with the fully symmetric states in the sdf interacting boson approximation model. A systematic study of the sdf-IBA model showed that the constructed Hamiltonian can successfully describe the strong octupole correlations in the deformed nuclei. We showed that the interacting boson approximation may account for many of these K ^π ?=?0⁺ states. It was found that the calculated energy spectra of the gadolinium isotopes agree quite well with the experimental data. The observed B(E2) values were also calculated and compared with the experimental data.     

Fourier Transform Rheology as an innovative morphological characterization technique for the emulsion volume average radius and its distribution

This article extends previous works on emulsion characterization via Fourier Transform Rheology. The interest here is on the effects of (i) polydispersity and (ii) high volume fraction (often associated with commercial samples) on the nonlinear rheological behavior. To analyze the effects of polydispersity on the LAOS measurements, the investigated samples were characterized with respect to their volume average radius, [R](43), and the polydispersity index of the distribution. As the nonlinear mechanical emulsion value E(0) introduced in the literature is a function of both nonlinear rheological parameters, such as I(5/3), as well as emulsion properties including the volume average radius, interfacial tension and viscosities of the matrix and dispersed phase, it is, therefore, a useful tool for emulsion characterization. In addition, the analysis of the higher harmonic ratios, I(7/5), has been demonstrated to provide information about the width of the distribution. With respect to the characterization of the high volume fraction samples, these first experiments on commercial w/o-emulsions were shown to relate nonlinear rheological properties to the droplet size and droplet size distribution of highly filled systems, demonstrating that LAOS experiments can give useful insights on the average droplet size and its distribution.     

Percolating granular superconductor in a magnetic field

An array of Josephson tunnel junctions is studied as a model for granular superconductors. We determine the critical line in the (H, T)-plane, separating the phase-coherent and incoherent region as a function of the magnetic field. Both positional disorder and junction-dilution are treated. Approaching the percolation threshold from above, the critical exponent of the upper critical field is found to be 0.60±0.03.     

On chain morphisms of commutative rings

Résumé  On dit qu’un homomorphismef :A →B d’anneaux commutatifs est un morphisme de cha?ne (resp., den-cha?ne pour un entiern ≥ 1) si toute cha?ne d’idéaux premiers (resp., d’au plusn idéaux premiers) deA se relève en une cha?ne d’idéaux premiers deB. Sif est un morphisme den-cha?ne, alorsf n’est pas forcément un morphisme de (n + 1)-cha?ne, même siA etB sont des anneaux intègres, doncf n’est pas un morphisme de cha?ne. Sif est un morphisme den-cha?ne pour toutn, alorsf est un morphisme de cha?ne. Un morphisme de cha?ne n’est pas forcément un morphisme de cha?ne universel. Pour tout entiern ≥ 2,f est universellement un morphisme den-cha?ne si et seulement sif est universellement un morphisme de cha?ne. Un morphisme qui est universellement de cha?ne et universellement incomparable n’est pas nécessairement entier, même siA etB sont des anneaux intègres de dimension 1 (au sens de Krull).      

Magnetization in the two-dimensional Hubbard model: a numerical study

The Projector Quantum Monte Carlo method is used to study the two-dimensional Hubbard model with generalized boundary conditions at half-filling. The convergence of the algorithm depends strongly on the initial trial state. Spin-density waves provide an excellent trial state for the case of weak and of strong correlations. This choice of a trial state with broken symmetry allows us to calculate directly the staggered (or sublattice) magnetization m ₀ as a function of the on-site repulsion U. The use of general boundary conditions strongly reduces finite size effects in m ₀.     

DEPTH MEASUREMENTS AND HISTOPATHOLOGICAL CHARACTERIZATION OF PHOTODYNAMIC THERAPY GENERATED NORMAL BRAIN NECROSIS AS A FUNCTION OF INCIDENT OPTICAL ENERGY DOSE

The response of normal brain to photodynamic therapy (PDT) was investigated in 62 Fisher rats. The animals were injected i.p. with Photofrin II (12.5 mg/kg). Forty-eight hours following injection, an area of dura 5 mm in diameter over the frontal cortex was photoactivated with red light (632 +/- 2 nm) at 100 mW cm-2, with no contributing thermal increases, at optical energy doses ranging from 1-140 J cm-2 from an argon-pumped dye laser. Appropriate controls were also prepared. Brain tissue samples for histological analysis were taken 24 h following PDT treatment. Maximum lesion depth perpendicular to the pial brain surface, was measured using an eyepiece micrometer. Lesions of increasing depth were generated as the incident optical energy dose was increased. Fitting the depth of necrosis to a natural log dependence of incident optical dose yielded a slope of 0.83 mm/ln J cm-2 (r2 = 0.99). The intercept of 1.47 J cm-2 indicated the energy dose below which no normal tissue damage would occur at the incident laser intensity of 100 mW cm-2. The smallest lesions consisted almost exclusively of isolated neuronal injury and neuropil vacuolation, suggestive of an early ischemic lesion. Damage at the upper energy levels (35-140 J cm-2) consisted of complete coagulative necrosis identical to that induced by an arterial occlusion. The existence of viable tissue alongside neurons in various stages of necrosis at low energy levels (less than 35 J cm-2) is suggestive of reversible injury and possibly clinically relevant treatment levels.     

PHOTOREACTIVITY OF 5-GERANOXYPSORALEN AND LACK OF PHOTOREACTION WITH DNA

5-Geranoxypsoralen, commonly called bergamottin, a major furocoumarin contained in bergamot oil, is reported in vitro as a highly photoreactive psoralen. In ethanol, it exhibits quite a high triplet state quantum yield (approximately 0.37). The triplet state is involved in subsequent photochemistry which depends on the initial concentration and on the presence of oxygen. In contrast to most psoralens, absorption and fluorescence data suggest that 5-geranoxypsoralen does not interact with DNA in the dark. No UVA-induced interstrand cross-links in DNA were shown.     

Differential non-destructive image current detection in a fourier transform quadrupole ion trap

Dual-detector differential non-destructive Fourier transform detection in a quadrupole ion trap is shown to improve signal intensity and reduce noise compared with spectra recorded using a single detector. A larger area detector in each end-cap electrode is machined to fit its hyperbolic shape and so minimize field imperfections on the z-axis. Argon, acetophenone and bromobenzene spectra were recorded to allow a comparison between single- and dual-detector (differential) modes of detection and to demonstrate the improvement achieved with differential detection. Copyright 1999 John Wiley & Sons, Ltd.     

Tumor Oxygenation Changes Post-Photodynamic Therapy

Abstract— Tumor oxygenation after a photodynamic therapy (PDT) treatment is a critical factor for understanding the post-treatment metabolic pathway of the tumor. It also provides important information for designing combination therapy of PDT and other oxygen-dependent anticancer modalities. In this study, mammary carcinoma in flank and hind leg of C3H mice were subjected to PDT at either subcurative or curative level (12.5 mg/kg Photofrin; 200 or 600 J/cm², respectively). The before and post-PDT tumor oxygenation was measured with an oxygen-sensitive microelectrode. The data revealed that tumor oxygenation at the time of PDT has a profound effect on posttreatment tumor oxygenation, which may largely be due to an interplay between direct PDT cytotoxicity and PDT damage to the tumor microvasculature. Transient reoxygenation occurred after PDT, which may provide a window for improved combination therapy for other oxygen-dependent modalities.