PubMed Health⌕ Search

Biomedical subjects

Y Asano

Publications and source records attributed to Y Asano.

At least 19 recordsLinked to original sources
PubMed2003

Evidence for a narrow S = +1 baryon resonance in photoproduction from the neutron.

The gamman-->K(+)K(-)n reaction on 12C has been studied by measuring both K+ and K- at forward angles. A sharp baryon resonance peak was observed at 1.54+/-0.01 GeV/c(2) with a width smaller than 25 MeV/c(2) and a Gaussian significance of 4.6sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can be interpreted as a molecular meson-baryon resonance or alternatively as an exotic five-quark state (uuddsmacr;) that decays into a K+ and a neutron. The resonance is consistent with the lowest member of an antidecuplet of baryons predicted by the chiral soliton model.

Journal Article↗
PubMed2003

Observation of B0-->pLambda(pi)(-).

We report the first observation of the charmless hyperonic B decay, B0-->pLambda(pi)(-), using a 78 fb(-1) data sample recorded on the Upsilon(4S) resonance with the Belle detector at KEKB. The measured branching fraction is B(B0-->pLambda(pi)(-))=(3.97(+1.00)(-0.80)+/-0.56)x10(-6). Searches for B0-->pLambda(K)- and pSigma(0)pi(-) yield no significant signals and we set 90% confidence-level upper limits of B(B0-->pLambda(K)-)<8.2x10(-7) and B(B0-->pSigma(0)pi(-))<3.8x10(-6).

Journal Article↗
PubMed2003

Observation of B0 -->D0K0 and B0 -->D0K*0 decays.

We report on a search for B(0)-->D(*0)K(*0) decays based on 85 x 10(6) BB events collected with the Belle detector at KEKB. The B(0)-->D0K(0) and B(0)-->D0K(*0) decays have been observed for the first time with the branching fractions B(B(0)-->D0K(0))=(5.0(+1.3)(-1.2)+/-0.6)x10(-5) and B(B(0)-->D0K(*0))=(4.8(+1.1)(-1.0)+/-0.5)x10(-5). No significant signal has been found for the B(0)-->D(*0)K*0) and B(0)-->D(*0)K(*0) decay modes, and upper limits at 90% C.L. are presented.

Journal Article↗
PubMed2003

Studies of the decay B+/- -->D(CP)K+/-.

We report studies of the Cabibbo-suppressed decay B+/--->D(CP)K+/-, where D(CP) denotes CP eigenstates of the D0-D0; system. The analysis is based on a 29.1 fb(-1) sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) storage ring. We measure ratios of branching fractions, relative to Cabibbo-favored B+/--->D(CP)pi(+/-), of B(B--->D1K-)/B(B--->D1pi(-))=0.125+/-0.036+/-0.010 and B(B--->D2K-)/B(B--->D2pi(-))=0.119+/-0.028+/-0.006; the index 1 (2) denotes the CP=+1 (-1) eigenstate. We also extract the partial rate asymmetries for B+/--->D(CP)K+/-, finding A(1)=0.29+/-0.26+/-0.05 and A(2)=-0.22+/-0.24+/-0.04.

Journal Article↗
PubMed2003

Observation of the decay B0-->lambda+cp.

We report the measurement of the charmed baryonic decay B(0)-->Lambda(+)(c)p with a branching fraction of (2.19(+0.56)(-0.49)+/-0.32+/-0.57)x10(-5) and a statistical significance of 5.8 sigma. The errors are statistical, systematic, and the error of the Lambda(+)(c)-->pK(-)pi(+) decay branching fraction. This is the first observation of a two-body baryonic B decay. The analysis is based on 78.2 fb(-1) of data accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider.

Journal Article↗
PubMed2003

Measurement of branching fractions for B-->eta(c)K(*) decays.

We report measurements of branching fractions for charged and neutral B-->eta(c)K decays where the eta(c) meson is reconstructed in the K(0)(S)K+/-pi(-/+), K+K-pi(0), K(*0)K-pi(+), and pp; decay channels. The neutral B0 channel is a CP eigenstate and can be used to measure the CP violation parameter sin(2phi(1). We also report the first observation of the B0-->eta(c)K(*0) mode. The results are based on an analysis of 29.1 fb(-1) of data collected by the Belle detector at KEKB.

Journal Article↗
PubMed2003

Measurement of the electroweak penguin process B-->X(s)l+l-.

We report the first measurement of the branching fraction for the inclusive decay B-->X(s)l(+)l(-), where l is either an electron or a muon, and X(s) is a hadronic recoil system that contains an s quark. We analyzed a data sample of 65.4 x 10(6) B meson pairs collected with the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. We find B(B-->X(s)l(+)l(-))=[6.1 +/-1.4(stat) +1.4-1.1(syst)] x 10(-6) for dilepton masses greater than 0.2 GeV/c(2).

Journal Article↗
PubMed2003

Elevated circulating soluble CD40 ligand in patients with mixed connective tissue disease.

Abnormalities of CD40 ligand have been demonstrated in various kinds of diseases. Our objective was to determine serum soluble CD40 ligand (sCD40L) levels in patients with mixed connective tissue disease (MCTD). Serum sCD40L levels of 23 patients with MCTD and 21 healthy individuals were measured with specific enzyme-linked immunosorbent assays. Serum levels of sCD40L were significantly higher in patients with MCTD than in healthy individuals (median 0.179 ng/ml vs 0.99 ng/ml, 25th-75th percentile; 0.117-0.296 ng/ml vs 0.82-1.70 ng/ml, P<0.005), whereas there were no significant correlation between elevated serum sCD40L levels and clinical or serological features in patients with MCTD. These results suggest that sCD40L plays a role in the pathogenesis of MCTD. Further studies are needed to clarify this.

Adult↗
PubMed2003

Plasma plasmin-alpha2-plasmin inhibitor complex levels are increased in systemic sclerosis patients with pulmonary hypertension.

OBJECTIVE: To determine the frequency and clinical significance of plasma plasmin-alpha(2)-plasmin inhibitor complex (PIC) in patients with systemic sclerosis (SSc). METHODS: Plasma samples from 74 patients with SSc and 32 healthy volunteers were examined by a specific enzyme-linked immunosorbent assay. RESULTS: Elevated plasma PIC levels were present in 35 of the 74 patients (47.3%) with SSc. The patients with elevated plasma PIC levels had pulmonary hypertension (PH) at a significantly higher incidence than those with normal PIC levels (31.4 vs 7.7%, P<0.01). When PH was classified into isolated PH (IPH) and secondary PH (SPH), the presence of IPH was significantly greater in patients with elevated PIC levels than in those with normal levels (25.7 vs 5.1%, P<0.02). CONCLUSIONS: These results suggest that plasma PIC levels may be a marker of PH, especially IPH, in patients with SSc.

Adult↗
PubMed2003

Trans-Tenon's retrobulbar triamcinolone infusion for the treatment of uveitis.

AIM: To assess efficacy and complications of trans-Tenon's retrobulbar infusion of triamcinolone acetonide for posterior uveitic inflammation. METHODS: Non-randomised, uncontrolled, retrospective study of 51 eyes of 37 patients who underwent triamcinolone infusion for vitritis, cystoid macular oedema (CMO), or posterior retinal vasculitis using a long blunt cannula via an incision made through conjunctiva and Tenon's capsule. RESULTS: Overall clinical efficacy was 86%; 96% for vitritis, 82% for CMO, and 33% for posterior retinal vasculitis. Mean visual acuity improved within 1 month after triamcinolone infusion (p <0.05). Cataract progression and intraocular pressure elevation were observed in 31% and 27% of eyes, respectively. CONCLUSION: Trans-Tenon's retrobulbar triamcinolone infusion may be a safe and effective treatment for posterior uveitic inflammation.

Adult↗
PubMed2003

Combined treatment with nafamostat mesilate and aspirin prevents heparin-induced thrombocytopenia in a hemodialysis patient.

We report on the management of a 36-year-old hemodialysis patient with heparin-induced thrombocytopenia (HIT, type II) and clot formation in extracorporeal circulation. Platelet aggregation test and measurement of anti-platelet factor 4/heparin complex antibody by enzyme-linked immunosorbent assay revealed to us that our patient had developed HIT. Instead of heparin, we used nafamostat mesilate (NM) as an anticoagulant during hemodialysis, but could not completely prevent HIT-induced thrombocytopenia or clot formation in the extracorporeal circuit. Combined use of NM and aspirin completely inhibited platelet aggregation, decrease in platelet count and clot formation in the extracorporeal circuit.

Adult↗
PubMed2002

Measurement of the B(0)-B(0) mixing parameter Deltam(d) using semileptonic B0 decays.

We present a measurement of the B0-Bmacr;(0) mixing parameter Deltam(d) using neutral B meson pairs in a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We exclusively reconstruct one neutral B meson in the semileptonic B0-->D(*-)l(+)nu decay mode and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two flavor-tagged B meson decay points, we obtain Deltam(d)=(0.494+/-0.012+/-0.015) ps(-1), where the first error is statistical and the second error is systematic.

Journal Article↗
PubMed2002

Observation of D+(s)K- and evidence for D+(s)pi- final states in neutral B decays.

We report the first observation of a B meson decay that is not accessible by a direct spectator process. The channel B(0)-->D(+)(s)K- is found in a sample of 85 x 10(6) BB; events, collected with the Belle detector at KEKB, with a branching fraction B(B(0)-->D(+)(s)K-)=(4.6(+1.2)(-1.1)+/-1.3) x 10(-5). We also obtain evidence for the B0-->D(+)(s)pi(-) decay with branching fraction B(B0-->D(+)(s)pi(-))=(2.4(+1.0)(-0.8)+/-0.7) x 10(-5). This value may be used to extract a model-dependent value of |V(ub)|.

Journal Article↗
PubMed2002

Radiative B meson decays into kpigamma and kpipigamma final states.

We report observations of radiative B meson decays into the K+pi(-)gamma and K+pi(-)pi(+)gamma final states. In the B0-->K+pi(-)gamma channel, we present evidence for decays via an intermediate tensor meson state with a branching fraction of B(B0-->K(*)(2)(1430)(0)gamma)=[1.3+/-0.5(stat)+/-0.1(syst)]x10(-5). We measure the branching fraction B(B+-->K+pi(-)pi(+)gamma)=[2.4+/-0.5(stat) +0.4-0.2(syst)]x10(-5), in which the B+-->K(*0)pi(+)gamma and B+-->K+rho(0)gamma channels dominate. The analysis is based on a data set of 29.4 fb(-1) recorded by the Belle experiment at the KEKB collider.

Journal Article↗
PubMed2002

Observation of B+/- -->omegaK+/- decay.

We report the first observation of the charmless two-body mode B+/--->omegaK+/- decay, and a new measurement of the branching fraction for the B+/--->omegapi(+/-) decay. The measured branching fractions are B(B+/--->omegaK+/-)=(9.2(+2.6)(-2.3)+/-1.0)x10(-6) and B(B+/--->omegapi(+/-))=(4.2(+2.0)(-1.8)+/-0.5)x10(-6). We also measure the partial rate asymmetry of B+/--->omegaK+/- decays and obtain A(CP)=-0.21+/-0.28+/-0.03. The results are based on a data sample of 29.4 fb(-1) collected on the Upsilon(4S) resonance by the Belle detector at the KEKB e(+)e(-) collider.

Journal Article↗
PubMed2002

Observation of B(0)-->D((*)0)pp.

The B meson decay modes B-->Dpp; and B-->D(*)pp; have been studied using 29.4 fb(-1) of data collected with the Belle detector at KEKB. The B;(0)-->D(0)pp; and B;(0)-->D(*0)pp; decays have been observed for the first time with branching fractions B(B;(0)-->D(0)pp;)=(1.18+/-0.15+/-0.16)x10(-4) and B(B;(0)-->D(*0)pp;)=(1.20(+0.33)(-0.29)+/-0.21)x10(-4). No signal has been found for the B+-->D(+)pp; and B+-->D(*+)pp; decay modes, and the corresponding upper limits at 90% C.L. are presented.

Journal Article↗