Evidence for CP-Violating Asymmetries in B0->pi+pi- Decays and Constraints on the CKM Angle phi2

We present an improved measurement of CP-violating asymmetries in B0 -> pi+ pi- decays based on a 78 fb^-1 data sample collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one neutral B meson as a B0 -> pi+ pi- CP eigenstate and identify the flavor of the accompanying B meson from inclusive properties of its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes Apipi = +0.77+/-0.27(stat)+/-0.08(syst) and Spipi = -1.23+/-0.41(stat)+0.08/-0.07(syst), where the statistical uncertainties are determined from Monte Carlo pseudo-experiments. We obtain confidence intervals for CP-violating asymmetry parameters Apipi and Spipi based on a frequentist approach. We rule out the CP-conserving case, Apipi=Spipi=0, at the 99.93% confidence level. We discuss how these results constrain the value of the CKM angle phi2.Comment: 26 pages, 13 figures, submitted to Phys. Rev.

Frequent traces of EBV infection in Hodgkin and non-Hodgkin lymphomas classified as EBV-negative by routine methods: expanding the landscape of EBV-related lymphoma

peer-reviewedThe Epstein–Barr virus (EBV) is linked to various B-cell lymphomas, including Burkitt lymphoma (BL), classical Hodgkin lymphoma (cHL) and diffuse large B-cell lymphoma (DLBCL) at frequencies ranging, by routine techniques, from 5 to 10% of cases in DLBCL to >95% in endemic BL. Using higher-sensitivity methods, we recently detected EBV traces in a few EBV-negative BL cases, possibly suggesting a “hit-and-run” mechanism. Here, we used routine and higher-sensitivity methods (qPCR and ddPCR for conserved EBV genomic regions and miRNAs on microdissected tumor cells; EBNA1 mRNA In situ detection by RNAscope) to assess EBV infection in a larger lymphoma cohort [19 BL, 34 DLBCL, 44 cHL, 50 follicular lymphomas (FL), 10 T-lymphoblastic lymphomas (T-LL), 20 hairy cell leukemias (HCL), 10 mantle cell lymphomas (MCL)], as well as in several lymphoma cell lines (9 cHL and 6 BL). qPCR, ddPCR, and RNAscope consistently documented the presence of multiple EBV nucleic acids in rare tumor cells of several cases EBV-negative by conventional methods that all belonged to lymphoma entities clearly related to EBV (BL, 6/9 cases; cHL, 16/32 cases; DLBCL, 11/30 cases), in contrast to fewer cases (3/47 cases) of FL (where the role of EBV is more elusive) and no cases (0/40) of control lymphomas unrelated to EBV (HCL, T-LL, MCL). Similarly, we revealed traces of EBV infection in 4/5 BL and 6/7 HL cell lines otherwise conventionally classified as EBV negative. Interestingly, additional EBV-positive cases (1 DLBCL, 2 cHL) relapsed as EBV-negative by routine methods while showing EBNA1 expression in rare tumor cells by RNAscope. The relapse specimens were clonally identical to their onset biopsies, indicating that the lymphoma clone can largely loose the EBV genome over time but traces of EBV infection are still detectable by high-sensitivity methods. We suggest EBV may contribute to lymphoma pathogenesis more widely than currently acknowledged

Sequence Variations of Latent Membrane Protein 2A in Epstein-Barr Virus-Associated Gastric Carcinomas from Guangzhou, Southern China

Latent membrane protein 2A (LMP2A), expressed in most Epstein-Barr virus (EBV)-associated malignancies, has been demonstrated to be responsible for the maintenance of latent infection and epithelial cell transformation. Besides, it could also act as the target for a CTL-based therapy for EBV-associated malignancies. In the present study, sequence variations of LMP2A in EBV-associated gastric carcinoma (EBVaGC) and healthy EBV carriers from Guangzhou, southern China, where nasopharyngeal carcinoma (NPC) is endemic, were investigated. Widespread sequence variations in the LMP2A gene were found, with no sequence identical to the B95.8 prototype. No consistent mutation was detected in all isolates. The immunoreceptor tyrosine-based activation motif (ITAM) and PY motifs in the amino terminus of LMP2A were strictly conserved, suggesting their important roles in virus infection; while 8 of the 17 identified CTL epitopes in the transmembrane region of LMP2A were affected by at least one point mutation, which may implicate that the effect of LMP2A polymorphisms should be considered when LMP2A-targeted immunotherapy is conducted. The polymorphisms of LMP2A in EBVaGC in gastric remnant carcinoma (GRC) were for the first time investigated in the world. The LMP2A sequence variations in EBVaGC in GRC were somewhat different from those in EBVaGC in conventional gastric carcinoma. The sequence variations of LMP2A in EBVaGC were similar to those in throat washing of healthy EBV carriers, indicating that these variations are due to geographic-associated polymorphisms rather than EBVaGC-associated mutations. This, to our best knowledge, is the first detailed investigation of LMP2A polymorphisms in EBVaGC in Guangzhou, southern China, where NPC is endemic

μSR studies of the interaction between magnetism and superconductivity in κ-BETS2FeCl4

Zero field (ZF) muon spin relaxation measurements on the organic metal κ-BETS2FeCl4 clearly show the formation of an antiferromagnetically ordered state below TN = 0.45 K. The magnetic order remains unperturbed on cooling through the superconducting transition Tc ∼0.17 K, providing unambiguous evidence for the coexistence of antiferromagnetic order and superconductivity in this system. Detailed studies of the internal field distribution show contrasting behavior for different muon sites and provide experimental evidence for an ordered spin structure in the BETS layers in addition to that taking place in the Fe layers. © 2002 Elsevier Science B.V. All rights reserved

μSR study of the interaction between magnetism and superconductivity in κ-BETS₂GaCl₄

Zero field (ZF) muon spin relaxation measurements on the organic metal kappa-BETS2FeCl4 clearly show the formation of an antiferromagnetically ordered state below T-N = 0.45 K. The magnetic order remains unperturbed on cooling through the superconducting transition T-c similar to0.17 K, providing unambiguous evidence for the coexistence of antiferromagnetic order and superconductivity in this system. Detailed studies of the internal field distribution show contrasting behavior for different muon sites and provide experimental evidence for an ordered spin structure in the BETS layers in addition to that taking place in the Fe layers. (C) 2002 Elsevier Science B.V. All rights reserved

Expression Profile of MicroRNAs in Epstein-Barr Virus-Infected AGS Gastric Carcinoma Cells

Latent infection with Epstein-Barr virus (EBV) is responsible for multiple types of malignancies, including 10% of all gastric carcinomas. The microRNA (miRNA) expression in several EBV-infected AGS gastric carcinoma cell lines was determined. Infected cells expressed the viral BamHI A rightward transcript (BART) miRNAs at high levels and had consistently decreased expression of a small fraction of cellular miRNAs with specific downregulation of tumor suppressor miRNAs. These changes likely reflect expression of the viral noncoding RNAs and not latent protein expression