We study the S-wave interaction of mesons with baryons in the strangeness Sϭ0 sector in a coupled channel unitary approach. The basic dynamics is drawn from the lowest order meson-baryon chiral Lagrangians. Small modifications inspired by models with explicit vector meson exchange in the t channel are also considered. In addition the N channel is included and shown to have an important repercussion in the results, particularly in the isospin 3/2 sector. The N*(1535) resonance is dynamically generated and appears as a pole in the second Riemann sheet with its mass, width, and branching ratios in fair agreement with experiment. A ⌬(1620) resonance also appears as a pole at the right position although with a very large width, coming essentially from the coupling to the N channel, in qualitative agreement with experiment.

Poly(methyl methacrylate) (PMMA) was melt mixed 30:70 into polystyrene (PS) with and without symmetric P(S-b-MMA) diblock copolymers. The molecular weight of the components was varied. After 5 min of shear mixing, the PMMA was dispersed into roughly spherical, submicron particles. Particle size was measured by light scattering and transmission electron microscopy. As little as 1% copolymer led to a significant reduction in PMMA particle size, although larger amounts were needed to make the particles stable to annealing (180 °C for 15 min). The principle role of block copolymers in controlling morphology appears to be in preventing coalescence. Preventing dynamic coalescence leads to size reduction, while preventing static coalescence results in stability or compatibilization. We estimate that less than 5% of the interface needs to be covered to prevent dynamic coalescence while ∼20% is necessary to impart static stability. Mobility, critical micelle concentration, and molecular weight of the block copolymer also appear to be important. Lowering the molecular weight of the PMMA phase from 43 000 to 11 000 resulted in dramatically lower particle size (700 vs 60 nm). These variables are discussed in terms of a qualitative balance between rate of diffusion and rate of area generation during blending.

Abstract.Existence of the H-dibaryon in the flavor SU(3) symmetric limit is studied by full QCD simulations on the lattice, in the approach recently developed for the baryon-baryon (BB) interactions. Potential of the flavor-singlet BB channel is derived from the Nambu-Bethe-Salpeter wave function, and a bound H-dibaryon is discovered from it, with the binding energy of 20-50 MeV for the pseudo-scalar meson mass of 469-1171 MeV.

Background and Purpose-The Middle Cerebral Artery Embolism Local Fibrinolytic Intervention Trial (MELT) Japan was organized to determine the safety and clinical efficacy of intraarterial infusion of urokinase (UK) in patients with stroke within 6 hours of onset. Methods-Patients with ischemic stroke presenting within 6 hours of onset and displaying occlusions of the M1 or M2 portion of the middle cerebral artery on carotid angiography were randomized to the UK or control groups. Clinical outcome was assessed by the modified Rankin Scale, National Institutes of Health Stroke Scale, and Barthel Index. Results-The Independent Monitoring Committee recommended stopping the trial after approval of intravenous infusion of recombinant tissue plasminogen activator in Japan. A total of 114 patients underwent randomization, 57 patients in each group. Background characteristics were comparable between the 2 groups. The primary end point of favorable outcome (modified Rankin Scale 0 to 2) at 90 days was somewhat more frequent in the UK group than in the control group (49.1% and 38.6%, OR: 1.54, 95% CI: 0.73 to 3.23) but did not reach a significant level (Pϭ0.345). However, excellent functional outcome (modified Rankin Scale 0 to 1) at 90 days, a preplanned secondary end point, was more frequent in the UK group than in the control group (42.1% and 22.8%, Pϭ0.045, OR: 2.46, 95% CI: 1.09 to 5.54). There were significantly more patients with National Institutes of Health Stroke Scale 0 or 1 at 90 days in the UK group than the control group (Pϭ0.017). The 90-day cumulative mortality was 5.3% in the UK group and 3.5% in the control group (Pϭ1.000), and intracerebral hemorrhage within 24 hours of treatment occurred in 9% and 2%, respectively (Pϭ0.206). Conclusions-The trial was aborted prematurely and the primary end point did not reach statistical significance.Nevertheless, the secondary analyses suggested that intraarterial fibrinolysis has the potential to increase the likelihood of excellent functional outcome.

The flavor-singlet H dibaryon, which has strangeness -2 and baryon number 2, is studied by the approach recently developed for the baryon-baryon interactions in lattice QCD. The flavor-singlet central potential is derived from the spatial and imaginary-time dependence of the Nambu-Bethe-Salpeter wave function measured in N(f)=3 full QCD simulations with the lattice size of L≃2,3,4  fm. The potential is found to be insensitive to the volume, and it leads to a bound H dibaryon with the binding energy of 30-40 MeV for the pseudoscalar meson mass of 673-1015 MeV.

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We sought to determine whether artherosclerosis may be accelerated in uremic patients on maintenance hemodialysis and investigated the risk factors for carotid and femoral atherosclerosis in such patients. High-resolution B-mode ultrasonography was used to determine the intima-media thickness (IMT) of the carotid and femoral arteries in 199 hemodialysis patients and 81 age-matched healthy controls subjects. The IMT values of the carotid and femoral arteries in the hemodialysis patients were significantly higher than in age-matched control subjects in most age groups. The IMT values of the carotid or femoral artery were significantly correlated with age in both the hemodialysis patients and the control subjects. There was a significant relationship between the IMT values of the two arteries in the hemodialysis patients (r = 0.418, P = 0.0001) and in the control subjects (r = 0.321, P = 0.0037). Multiple regression analysis showed that age, cigarette smoking, and uremic state were independent risk factors for atherosclerosis of both arteries in the patients and the control subjects (R2 = 0.174, P < 0.0001; R2 = 0.205, P < 0.0001, respectively). In the hemodialysis patients, the independent risk factors associated with the extent of the IMT of the carotid artery were age, cigarette smoking, and serum phosphorus level (R2 = 0.230, P < 0.0001), while those associated with the extent of the IMT of the femoral artery were age, cigarette-smoking, and serum m-PTH level (R2 = 0.230, P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Baryon-baryon potentials are obtained from 3-flavor QCD simulations with the lattice volume L ≃ 4 fm, the lattice spacing a ≃ 0.12 fm, and the pseudo-scalar-meson mass M ps = 469 -1171 MeV. The NN scattering phase-shifts and the mass of H-dibaryon in the flavor SU(3) limit are extracted from the resultant potentials by solving the Schrödinger equation. The NN phase-shifts in the SU(3) limit is shown to have qualitatively similar behavior as the experimental data. A bound H-dibaryon in the SU(3) limit is found to exist in the flavor-singlet J P = 0 + channel with the binding energy of about 26 MeV for the lightest quark mass M ps = 469 MeV. Effect of flavor SU(3) symmetry breaking on the H-dibaryon is estimated by solving the coupled-channel Schrödinger equation for ΛΛ-NΞ-ΣΣ with the physical baryon masses and the potential matrix obtained in the SU(3) limit: a resonant H-dibaryon is found between ΛΛ and NΞ thresholds in this treatment.