Single vortices observed as they enter NbSe2_2

We observe single vortices as they penetrate the edge of a superconductor using a high-sensitivity magneto-optical microscope. The vortices leap across a gap near the edge, a distance that decreases with increasing applied field and sample thickness. This behaviour can be explained by the combined effect of the geometrical barrier and bulk pinning.Comment: 2 pages, 1 figure, M2S-Rio proceeding

Low field vortex matter in YBCO: an atomic beam magnetic resonance study

We report measurements of the low field structure of the magnetic vortex lattice in an untwinned YBCO single-crystal platelet. Measurements were carried out using a novel atomic beam magnetic resonance (ABMR) technique. For a 10.7 G field applied parallel to the c-axis of the sample, we find a triangular lattice with orientational order extending across the entire sample. We find the triangular lattice to be weakly distorted by the a-b anisotropy of the material and measure a distortion factor, f = 1.16. Model-experiment comparisons determine a penetration depth, lambda_ab = 140 (+-20) nm. The paper includes the first detailed description of the ABMR technique. We discuss both technical details of the experiment and the modeling used to interpret the measurements.Comment: 44 pages, 13 figures, submitted to Phys. Rev. B Revision includes Postscript wrapped figures + minor typo

Bold fmri signal characteristics of s1- and s2-ssfp at 7 tesla

Contains fulltext : 135112.pdf (publisher's version ) (Open Access

Modeling and suppression of respiration induced B0-fluctuations in non-balanced steady-state free precession sequences at 7 Tesla

Object: To develop and evaluate a model for describing the S1 (S ) and S2 (S) phase in the presence of off-resonance frequency fluctuations, and to evaluate the performance of a novel interleaved navigator echo scheme. Materials and methods: Using the extended phase graph model, a linear phase term was added to the evolution of transverse states. An approximation for the total S2 phase was derived with one fit parameter τ, which serves as an effective lifetime of the S2 signal. The model was evaluated using synthetic and in vivo phase evolution data. In addition, a novel interleaved phase correction scheme for the nb-SSFP sequence was applied to BOLD-fMRI data, and the number of activated voxels before and after phase correction was determined. Results: The phases of S1 and S2 signals are significantly different from each other. The proposed nb-SSFP phase model provided a good description of the measured phase evolution data, and the approximate model for the S2 phase provided both at good fit to the data, as well as an effective lifetime of the S2 signal. In some subjects the phase contribution from older pathways was underestimated. In the BOLD-fMRI data, a twofold increase of the number of activated voxels for the S2 signal was observed, compared to no correction and a conventional navigator echo method. Conclusion: The different phase evolution of S1 and S2 signals can be qualitatively described by the proposed model, and detrimental phase history effects are significant at 7 Tesla when not appropriately corrected

Pranlukast: A review of its use in the management of asthma

Pranlukast (Onon\uae, Azlaire\uae), is an orally administered, selective, competitive antagonist of the cysteinyl leukotrienes (LT) C4, LTD4 and LTE4. It is indicated for the prophylactic treatment of chronic bronchial asthma in paediatric and adult patients. The efficacy of pranlukast 225mg twice daily in adults with mild to moderate asthma was demonstrated in double-blind, placebo- or azelastine-controlled studies of 4 or 8 weeks' duration. The drug at this dosage was superior to both comparators in improving mean attack scores and morning and/or evening peak expiratory flow rates, and decreasing the use of rescue bronchodilators (p < 0.05). In limited clinical studies, pranlukast 225mg twice daily appeared to be as effective as montelukast 10mg once daily and zafirlukast 40mg twice daily in adults with mild to moderate asthma. Tachyphylaxis was absent when the drug was administered for up to 4 years. In patients requiring high-dose inhaled corticosteroid therapy, pranlukast 225mg twice daily plus a halved dosage of inhaled corticosteroid was as effective as the original dosage of inhaled corticosteroid. Pranlukast was also effective in patients with mild to severe asthma in a clinical practice setting. In a double-blind trial, greater improvements in most outcome measures were observed with pranlukast than with oxatomide in children and adolescents with asthma. In clinical trials, pranlukast was well tolerated in adult and paediatric patients with asthma, with an adverse event profile similar to that of placebo. Gastrointestinal events and hepatic function abnormalities were the most commonly reported adverse events. No clinically significant differences in adverse event profiles between pranlukast, zafirlukast or montelukast were shown in limited comparisons. Although Churg-Strauss syndrome has been noted in pranlukast recipients, a direct causal relationship is unlikely. Conclusions: Pranlukast is a well tolerated and effective preventative treatment in adult and paediatric patients with persistent asthma of all severities. In some patients, pranlukast may be beneficial when added to low-dose inhaled corticosteroids; it may also be a viable alternative to increasing inhaled corticosteroid dosages. The efficacy of pranlukast relative to placebo has been confirmed; its efficacy relative to other therapy awaits further investigation. Nonetheless, pranlukast is a useful therapeutic option (with as-required short-acting \u3b22-agonists), either as preventative monotherapy for the treatment of mild persistent asthma or in conjunction with inhaled corticosteroids in the management of moderate or severe persistent asthma