Energy dependence of K−K^--"pppp" effective potential derived from coupled-channel Green's function

We investigate the energy dependence of a single-channel effective potential between the $K^-$ and the "$pp$"-core nucleus, which can be obtained as an $K^-$-"$pp$" equivalent local potential from a coupled-channel model for $\bar{K}(NN)$-$\pi(\Sigma N)$ systems. It turns out that the imaginary part of the resultant potential near the $\pi \Sigma N$ decay threshold can well approximate the phase space suppression factor of $K^-pp \to \pi \Sigma N$ decay modes. The effects on the pole position of the $\pi(\Sigma N)$ state in the $\pi \Sigma N$ channel are also discussed.Comment: 4 pages, 2 figures, Proceedings of the International Conference on Exotic Atoms and Related Topics (EXA2011), September 5-9, 2011, Wien, Austria, to appear in Hyperfine Interaction

Detection of circulating superantigens in an intensive care unit population

AbstractObjective: Plasma concentrations of superantigens were measured in an intensive care unit (ICU) population and the relationship of superantigen positive rates with the presence of sepsis was investigated.Methods: Plasma samples were collected at least twice a week from 78 patients whose primary diagnoses were abdominal disorders (n = 27), respiratory disorders (n = 11), trauma (n = 10), burns (n = 10), cardiovascular disorders (n = 4), neurological disorders (n = 2), and others (n = 14). Five different species of superantigens, i.e., staphylococcal enterotoxins A, B, and C (SEA, SEB, and SEC), toxic shock syndrome toxin-1 (TSST-1), and streptococcal pyrogenic exotoxin A (SPEA), were measured using an enzyme-linked immunosorbent assay.Results: Significant levels of plasma superantigens were detected in 16 patients. SEA was found in seven patients, SEB in four patients, SEC in two patients, TSST-1 in six patients, and SPEA in five patients. Superantigen detection rates were 6% (1/17) in patients without systemic inflammatory response syndrome (SIRS), 0% (0/21) in SIRS patients without infection, 31% (5/16) in septic patients without shock, and 42% (10/24) in septic shock patients.Conclusions: The presence of superantigens was confirmed in part of the ICU population. The role of superantigens in the pathogenesis of sepsis remains to be determined

Baseline tumour necrosis factor alpha levels predict the necessity for dose escalation of infliximab therapy in patients with rheumatoid arthritis

Objectives: To investigate the possible role of baseline plasma tumour necrosis factor alpha levels (baseline-TNF) on the clinical response to infliximab in patients with rheumatoid arthritis (RA). Methods: Patients with RA refractory to methotrexate received 3, 6, or 10 mg/kg of infliximab every 8 weeks, in a randomised, double-blind manner: the RISING study. Clinical response (disease activity score in 28 joints based on C-reactive protein or American College of Rheumatology core set) at week 54 and serum infliximab levels were compared in three patient groups with low, intermediate, or high baseline-TNF (TNF-low, TNF-int, or TNF-high). Results: In TNF-low patients, the clinical response to different doses of infliximab was comparable, whereas TNF-int patients exhibited a dose-dependent trend. In contrast, TNF-high patients (approximately 13% of the total patients) had a clinical response to 10 mg/kg significantly better than the response to 3 and 6 mg/kg of infliximab. In TNF-high patients, the median trough serum levels of infliximab were below the detection limit (<0.1 μg/ml) at 3 and 6 mg/kg but were greater than 2 μg/ml at 10 mg/kg, whereas the levels were approximately 1 μg/ml for each dosage group in TNF-low patients. Conclusion: In patients with RA, baseline-TNF is significantly associated with the clinical response to infliximab in patients with a high baseline-TNF. A higher dose of infliximab may be necessary in these patients, whereas lower doses of infliximab are sufficient for those with a low baseline-TNF. Baseline-TNF may be a useful measure for personalising the treatment of RA using infliximab

Signature of strange dibaryon in kaon-induced reaction

We examine how the signature of the strange-dibaryon resonances in the barKNN-piSigmaN system shows up in the scattering amplitude on the physical real energy axis within the framework of Alt-Grassberger-Sandhas (AGS) equations. The so-called point method is applied to handle the three-body unitarity cut in the amplitudes. We also discuss the possibility that the strange-dibaryon production reactions can be used for discriminating between existing models of the two-body barKN-piSigma system with Lambda(1405).Comment: 4 pages, 6 figures, talk given at The Fifth Asia-Pacific Conference on Few-Body Problems in Physics 2011 (APFB2011), held in Seoul, Korea, August 22-26, 201

Semiconductor Thermal Neutron Detector

The&nbsp; CdTe&nbsp; and&nbsp; GaN&nbsp; detector&nbsp; with&nbsp; a&nbsp; Gd&nbsp; converter&nbsp; have&nbsp; been developed&nbsp; and&nbsp; investigated&nbsp; as&nbsp; a&nbsp; neutron&nbsp; detector&nbsp; for neutron&nbsp; imaging.&nbsp; The&nbsp; fabricated&nbsp; Gd/CdTe&nbsp; detector&nbsp; with&nbsp; the&nbsp; 25&nbsp; mm&nbsp; thick&nbsp; Gd&nbsp; was&nbsp; designed&nbsp; on&nbsp; the&nbsp; basis&nbsp; of&nbsp; simulation results&nbsp; of&nbsp; thermal&nbsp; neutron&nbsp; detection&nbsp; efficiency&nbsp; and&nbsp; spatial&nbsp; resolution.&nbsp; The&nbsp; Gd/CdTe&nbsp; detector&nbsp; shows&nbsp; the&nbsp; detection&nbsp; of neutron&nbsp; capture&nbsp; gamma&nbsp; ray&nbsp; emission&nbsp; in&nbsp; the&nbsp; 155Gd(n,&nbsp; g)156Gd,&nbsp; 157Gd(n,&nbsp; g)158Gd&nbsp; and&nbsp; 113Cd(n,&nbsp; g)114Cd&nbsp; reactions&nbsp; and characteristic X-ray emissions due to conversion-electrons generated inside the Gd film. The observed efficient thermal neutron detection with the Gd/CdTe detector shows its promise in neutron radiography application. Moreover, a BGaN detector has also investigated to separate neutron signal from gamma-ray clearly.&nbsp;Keywords: detector, neutron, semiconductor, therma

Calculation of the 3^3He(in-flight K−K^-,nn) reaction for searching the deeply-bound K−ppK^-pp state

The formation of a deeply-bound $K^-pp$ state by the $^3$He(in-flight $K^-$,$n$) reaction is investigated theoretically in the distorted-wave impulse approximation using the Green's function method. The expected inclusive and semi-exclusive spectra at $p_{K^-}$ = 1.0 GeV/c and $\theta_n = 0^{\circ}$ are calculated for the forthcoming J-PARC E15 experiment. We employ optical potentials between the $K^-$ and ``$pp$'' core-nucleus, and demonstrate systematically the dependence of the spectral shape on $V_0$ and $W_0$, which are the real and imaginary parts of the strength for the optical potential, respectively. The necessary condition to observe a distinct peak of the $K^-pp$ bound state with $I=1/2$, $J^\pi=0^-$ in the spectrum turns out to be that the value of $V_0$ is deeper than $\sim-100$ MeV and $W_0$ shallower than $\sim-100$ MeV, of which the strength parameters come up to recent theoretical predictions.Comment: 18 pages, 6 figures, REVTeX 4, accepted for publication in Physics Letters

Localization and Quantum Hall Effect in Two-Dimensional Systems Under Strong Magnetic Fields(Transport and Fermiology)

Experimental researches of quantum transport properties of semiconductor two-dimensional electron systems in Si-MOSFETs and GaAs/AlGaAs heterostructures in high magnetic fields up to 27 T and at low temperatures down to 20 mK are performed. Analysis of the Hall conductivity of Si-MOSFETs based on a mobility edge model shows that the temperature dependence of the mobility edge can not be explained by existing theory of localization. The fractional quantum Hall effect is observed at the filling factor of 1/7 in heterostructures. Sample size dependence and magnetic field dependence of the breakdown of the integral quantum Hall effect in heterostructures reveal that the Hall current is carried not by the edge states but by the extended states in the localization in the bulk of the two-dimensional systems

Production of doubly strange hypernuclei via {\Xi}- doorways in the 16O(K-, K+) reaction at 1.8 GeV/c

We examine theoretically production of doubly strange hypernuclei, 16 {\Xi}-C and 16 {\Lambda}{\Lambda}C, in doublecharge exchange 16O(K-, K+) reactions using a distorted-wave impulse approximation. The inclusive K+ spectrum at the incident momentum pK- = 1.8 GeV/c and scattering angle {\theta}lab = 0^{\circ} is estimated in a one-step mechanism, K-p \to K+{\Xi}- via {\Xi}- doorways caused by a {\Xi}-p-{\Lambda}{\Lambda} coupling. The calculated spectrum in the {\Xi}- bound region indicates that the integrated cross sections are on the order of 7-12 nb/sr for significant 1- excited states with 14C(0+, 2+) \otimes s{\Lambda}p{\Lambda} configurations in 16 {\Lambda}{\Lambda}C via the doorway states of the spin-stretched 15N(1/2-, 3/2-) \otimes s{\Xi}- in 16 {\Xi}-C due to a high momentum transfer q{\Xi}- \approx 400 MeV/c. The {\Xi}- admixture probabilities of these states are on the order of 5-9%. However, populations of the 0+ ground state with 14C(0+) \otimes s2{\Lambda} and the 2+ excited state with 14C(2+) \otimes s2 {\Lambda} are very small. The sensitivity of the spectrum on the {\Xi}N-{\Lambda}{\Lambda} coupling strength enables us to extract the nature of {\Xi}N-{\Lambda}{\Lambda} dynamics in nuclei, and the nuclear (K-, K+) reaction can extend our knowledge of the S = -2 world.Comment: 10 pages, 3 figure