Measurement of the τ-lepton lifetime at Belle

The lifetime of the τ lepton is measured using the process e+ e- → τ+ τ- , where both τ leptons decay to 3πν(τ). The result for the mean lifetime, based on 711  fb(-1) of data collected with the Belle detector at the ϒ(4S) resonance and 60  MeV below, is τ=(290.17±0.53(stat)±0.33(syst))×10(-15)  s. The first measurement of the lifetime difference between τ+ and τ- is performed. The upper limit on the relative lifetime difference between positive and negative τ leptons is |Δτ|/τ<7.0×10(-3) at 90% C.L.

The impact of hepatitis B virus (HBV) infection on clinical outcomes of patients with diffuse large B-cell lymphoma

We performed a retrospective study to analyse the characteristics and clinical outcomes of diffuse large B-cell lymphoma (DLBCL) patients with hepatitis B virus (HBV) infection and compare with those without HBV infection. The occurrence of hepatitis after withdrawal of prophylactic antiviral treatment on completion of chemotherapy was also assessed. The HBsAg-positive patients were given prophylactic antiviral treatment until 6 months after finishing chemotherapy. A total of 81 patients were recruited with 16 in the HBsAg-positive group and 65 in the HBsAg-negative group. The clinical characteristics were similar in both groups of patients. There was no significant difference in complete remission rate between the two groups (63% in HBsAg-positive group vs. 54% in HBsAg-negative group, P = 0.59). There was also no statistically significant difference in overall survival between the two groups (P = 0.23). Four of the 16 HBsAg-positive patients (25%) had hepatitis after cessation of chemotherapy and prophylactic lamivudine. The mean time of onset of hepatitis was 3 months after stopping lamivudine. In conclusion, HBV infection did not appear to affect the prognosis of DLBCL patients given antiviral prophylaxis. It is reasonable to consider prophylactic antiviral therapy to extend to at least one year on completion of chemotherapy.

Search for bottomonium states in exclusive radiative Υ(2S) decays

We search for bottomonium states in Υ(2S) → (bb)γ decays with an integrated luminosity of 24.7  fb(-1) recorded at the Υ(2S) resonance with the Belle detector at KEK, containing (157.8±3.6)×10(6) Υ(2S) events. The (bb) system is reconstructed in 26 exclusive hadronic final states composed of charged pions, kaons, protons, and K(S)(0) mesons. We find no evidence for the state recently observed around 9975 MeV (X(bb)) in an analysis based on a data sample of 9.3×10(6) Υ(2S) events collected with the CLEO III detector. We set a 90% confidence level upper limit on the branching fraction B[Υ(2S) → X(bb)γ] × ∑(i)B[X(bb) → h(i)] < 4.9×10(-6), summed over the exclusive hadronic final states employed in our analysis. This result is an order of magnitude smaller than the measurement reported with CLEO data. We also set an upper limit for the ηb(1S) state of B[Υ(2S) → ηb(1S)γ] × ∑(i)B[ηb(1S) → h(i)] < 3.7×10(-6).

How we identify and count Aboriginal people--does it make a difference in estimating their disease burden?

INTRODUCTION

We examined the concordance between the Canadian Community Health Survey (CCHS) "identity" and "ancestry" questions used to estimate the size of the Aboriginal population in Canada and whether the different definitions affect the prevalence of selected chronic diseases.

METHODS

Based on responses to the "identity" and "ancestry" questions in the CCHS combined 2009-2010 microdata file, Aboriginal participants were divided into 4 groups: (A) identity only; (B) ancestry only; (C) either ancestry or identity; and (D) both ancestry and identity. Prevalence of diabetes, arthritis and hypertension was estimated based on participants reporting that a health professional had told them that they have the condition(s).

RESULTS

Of participants who identified themselves as Aboriginal, only 63% reported having an Aboriginal ancestor; of those who claimed Aboriginal ancestry, only 57% identified themselves as Aboriginal. The lack of concordance also differs according to whether the individual was First Nation, Métis or Inuit. The different method of estimating the Aboriginal population, however, does not significantly affect the prevalence of the three selected chronic diseases.

CONCLUSION

The lack of concordance requires further investigation by combining more cycles of CCHS to compare discrepancy across regions, genders and socio-economic status. Its impact on a broader list of health conditions should be examined.

Tumor vascularization is critical for oncolytic vaccinia virus treatment of peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) represents a significant clinical challenge for which there are few treatment options. Oncolytic viruses are ideal candidates for PC treatment because of their high tumor specificity, excellent safety profile and suitability for peritoneal delivery. Here, we described the use of vvDD-SR-RFP, a recombinant vaccinia virus, in xenograft and syngeneic models of colorectal PC. Colorectal cancer cell lines were highly susceptible to vvDD-SR-RFP replication and cytotoxicity. Intraperitoneal delivery of vvDD-SR-RFP on Day 12 to mice with colorectal carcinomatosis significantly improved survival whereas survival was not improved following virus treatment on Day 8, when tumors were smaller. Immunohistochemistry revealed early tumors had a poorly distributed network of blood vessels and lower proliferation index compared to later tumors. Virus infection was also restricted to tumor rims following Day 8 treatment, whereas it was disseminated in tumors treated on Day 12. Additionally, direct infection of tumor endothelium was observed and virus infection correlated with a loss of endothelial staining and induction of cell death. Our results demonstrate that tumor vasculature has a critical role in virus delivery and tumor response. This will have significant implications in the clinical setting, both in understanding timing of therapies and in designing combination treatment strategies.

Precision measurement of charged pion and kaon differential cross sections in e+ e- annihilation at sqrt[s]=10.52 GeV

Measurements of inclusive differential cross sections for charged pion and kaon production in e+ e- annihilation have been carried out at a center-of-mass energy of sqrt[s]=10.52  GeV. The measurements were performed with the Belle detector at the KEKB e+ e- collider using a data sample containing 113×10(6) e+ e- → qq events, where q={u,d,s,c}. We present charge-integrated differential cross sections dσ(h±)/dz for h±={π±,K±} as a function of the relative hadron energy z=2E(h)/sqrt[s] from 0.2 to 0.98. The combined statistical and systematic uncertainties for π± (K±) are 4% (4%) at z∼0.6 and 15% (24%) at z∼0.9. The cross sections are the first measurements of the z dependence of pion and kaon production for z>0.7 as well as the first precision cross section measurements at a center-of-mass energy far below the Z0 resonance used by the experiments at LEP and SLC.

An investigation of factors that influence general practitioners' referral of computed tomography scans in patients with headache

AIM

In assessing patients with headaches, general practitioners (GPs) play an important role in determining which patients require computed tomography (CT) scans. The purpose of this study was to identify factors that influence GPs' decisions to refer CT scans for patients with headaches.

MATERIALS AND METHODS

A self-administered survey was presented to GPs in Western Australia. One hundred and twenty-eight vignettes describing patients who may have required CT referral for headache were constructed encompassing six clinical variables. Nine vignettes, selected at random, were presented to each respondent. Respondents were asked if they would refer the patient for diagnostic imaging tests, if so, which imaging modalities would they request, how urgently and the perceived benefits of the requested imaging modality. Multinomial logistic regression was used for the multivariate analysis.

RESULTS

We received 105 completed questionnaires (21%). GPs were more likely to refer patients with headaches for diagnostic imaging and CT scans in the following clinical scenarios: patients with a history of colorectal cancer and epilepsy; and patients feeling unwell for the past 6 weeks and headache being exacerbated with valsalva manoeuvrers. Private health insurance and other respondent demographics such as GPs experience and site of care increased imaging referral.

CONCLUSION

GP's referral decisions of diagnostic imaging and CT examinations for patients with headaches are dependent on clinical scenarios and the likelihood of a significant pathology. Further research is required to identify the significant clinical findings with regard to the CT referrals and ensure that CT scans are not requested in patients who are unlikely to benefit.

Search for an H-dibaryon with a mass near 2mΛ in Υ(1S) and Υ(2S) decays

We report the results of a high-statistics search for H dibaryon production in inclusive Υ(1S) and Υ(2S) decays. No indication of an H dibaryon with a mass near the M(H)=2m(Λ) threshold is seen in either the H→Λpπ(-) or ΛΛ decay channels and 90% confidence level branching-fraction upper limits are set that are between one and two orders of magnitude below the measured branching fractions for inclusive Υ(1S) and Υ(2S) decays to antideuterons. Since Υ(1S,2S) decays produce flavor-SU(3)-symmetric final states, these results put stringent constraints on H dibaryon properties. The results are based on analyses of 102 million Υ(1S) and 158 million Υ(2S) events collected with the Belle detector at the KEKB e(+)e(-) collider.

Evidence for B- → τ- ν(τ) with a hadronic tagging method using the full data sample of Belle

We measure the branching fraction of B- → τ- ν(τ) using the full Υ(4S) data sample containing 772×10(6) BB pairs collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. Events with BB pairs are tagged by reconstructing one of the B mesons decaying into hadronic final states, and B- → τ- ν(τ) candidates are detected in the recoil. We find evidence for B- → τ- ν(τ) with a significance of 3.0 standard deviations including systematic errors and measure a branching fraction B(B- → τ- ν(τ))=[0.72(-0.25)(+0.27)(stat)±0.11(syst)]×10(-4).