Tests of Light-Lepton Universality in Angular Asymmetries of B^{0}→D^{*-}ℓν Decays

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189  fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.

Precise Measurement of the D_{s}^{+} Lifetime at Belle II

We measure the lifetime of the D_{s}^{+} meson using a data sample of 207  fb^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×10^{3} D_{s}^{+}→ϕπ^{+} decays. Our result is τ_{D_{s}^{+}}=(499.5±1.7±0.9)  fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

Search for a τ^{+}τ^{-} Resonance in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} Events with the Belle II Experiment

We report the first search for a nonstandard-model resonance decaying into τ pairs in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} events in the 3.6-10  GeV/c^{2} mass range. We use a 62.8  fb^{-1} sample of e^{+}e^{-} collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axionlike particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ pairs, ranging from 0.7 to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5  GeV/c^{2} and for the axionlike particle model over the entire mass range.

Measurement of CP Violation in B^{0}→K_{S}^{0}π^{0} Decays at Belle II

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6}  BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

Test of Light-Lepton Universality in the Rates of Inclusive Semileptonic B-Meson Decays at Belle II

We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189  fb^{-1} from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3  GeV/c to obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.

Search for an Invisible Z^{'} in a Final State with Two Muons and Missing Energy at Belle II

The L_{μ}-L_{τ} extension of the standard model predicts the existence of a lepton-flavor-universality-violating Z^{'} boson that couples only to the heavier lepton families. We search for such a Z^{'} through its invisible decay in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'}. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58 GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7  fb^{-1}. We find no excess over the expected standard-model background. We set 90%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3×10^{-3} at low Z^{'} masses to 1 at Z^{'} masses of 8  GeV/c^{2}.

Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II

We search for lepton-flavor-violating τ^{-}→e^{-}α and τ^{-}→μ^{-}α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8  fb^{-1}, produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ} and τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decays. We report 95% confidence-level upper limits on the branching-fraction ratio B(τ^{-}→e^{-}α)/B(τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ}) in the range (1.1-9.7)×10^{-3} and on B(τ^{-}→μ^{-}α)/B(τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ}) in the range (0.7-12.2)×10^{-3} for α masses between 0 and 1.6  GeV/c^{2}. These results provide the most stringent bounds on invisible boson production from τ decays.

Observation of e^{+}e^{-}→ωχ_{bJ}(1P) and Search for X_{b}→ωϒ(1S) at sqrt[s] near 10.75 GeV

We study the processes e^{+}e^{-}→ωχ_{bJ}(1P) (J=0, 1, or 2) using samples at center-of-mass energies sqrt[s]=10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7  fb^{-1} of integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the ϒ(4S) resonance. We report the first observation of ωχ_{bJ}(1P) signals at sqrt[s]=10.745  GeV. By combining Belle II data with Belle results at sqrt[s]=10.867  GeV, we find energy dependencies of the Born cross sections for e^{+}e^{-}→ωχ_{b1,b2}(1P) to be consistent with the shape of the ϒ(10753) state. These data indicate that the internal structures of the ϒ(10753) and ϒ(10860) states may differ. Including data at sqrt[s]=10.653  GeV, we also search for the bottomonium equivalent of the X(3872) state decaying into ωϒ(1S). No significant signal is observed for masses between 10.45 and 10.65  GeV/c^{2}.

Measurement of the Λ_{c}^{+} Lifetime

An absolute measurement of the Λ_{c}^{+} lifetime is reported using Λ_{c}^{+}→pK^{-}π^{+} decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the ϒ(4S) resonance, is 207.2  fb^{-1}. The result, τ(Λ_{c}^{+})=203.20±0.89±0.77  fs, where the first uncertainty is statistical and the second systematic, is the most precise measurement to date and is consistent with previous determinations.

Search for a Dark Photon and an Invisible Dark Higgs Boson in μ^{+}μ^{-} and Missing Energy Final States with the Belle II Experiment

The dark photon A^{'} and the dark Higgs boson h^{'} are hypothetical particles predicted in many dark sector models. We search for the simultaneous production of A^{'} and h^{'} in the dark Higgsstrahlung process e^{+}e^{-}→A^{'}h^{'} with A^{'}→μ^{+}μ^{-} and h^{'} invisible in electron-positron collisions at a center-of-mass energy of 10.58 GeV in data collected by the Belle II experiment in 2019. With an integrated luminosity of 8.34  fb^{-1}, we observe no evidence for signal. We obtain exclusion limits at 90% Bayesian credibility in the range of 1.7-5.0 fb on the cross section and in the range of 1.7×10^{-8}-200×10^{-8} on the effective coupling ϵ^{2}×α_{D} for the A^{'} mass in the range of 4.0  GeV/c^{2}<M_{A^{'}}<9.7  GeV/c^{2} and for the h^{'} mass M_{h^{'}}<M_{A^{'}}, where ϵ is the mixing strength between the standard model and the dark photon and α_{D} is the coupling of the dark photon to the dark Higgs boson. Our limits are the first in this mass range.

Precise Measurement of the D^{0} and D^{+} Lifetimes at Belle II

We report a measurement of the D^{0} and D^{+} lifetimes using D^{0}→K^{-}π^{+} and D^{+}→K^{-}π^{+}π^{+} decays reconstructed in e^{+}e^{-}→cc[over ¯] data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The data, collected at center-of-mass energies at or near the ϒ(4S) resonance, correspond to an integrated luminosity of 72  fb^{-1}. The results, τ(D^{0})=410.5±1.1(stat)±0.8(syst)  fs and τ(D^{+})=1030.4±4.7(stat)±3.1(syst)  fs, are the most precise to date and are consistent with previous determinations.

Search for Axionlike Particles Produced in e^{+}e^{-} Collisions at Belle II

We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e^{+}e^{-}→γa, a→γγ in the mass range 0.2<m_{a}<9.7  GeV/c^{2} using data corresponding to an integrated luminosity of (445±3)  pb^{-1}. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength g_{aγγ} of ALPs to photons at the level of 10^{-3}  GeV^{-1}. The limits are the most restrictive to date for 0.2<m_{a}<1  GeV/c^{2}.

Search for an Invisibly Decaying Z^{'} Boson at Belle II in e^{+}e^{-}→μ^{+}μ^{-}(e^{±}μ^{∓}) Plus Missing Energy Final States

Theories beyond the standard model often predict the existence of an additional neutral boson, the Z^{'}. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z^{'} in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'} and of a lepton-flavor-violating Z^{'} in e^{+}e^{-}→e^{±}μ^{∓}Z^{'}. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an L_{μ}-L_{τ} theory, into upper limits on the Z^{'} coupling constant at the level of 5×10^{-2}-1 for M_{Z^{'}}≤6  GeV/c^{2}.

Yttrium-90 radioembolization for colorectal cancer liver metastases in KRAS wild-type and mutant patients: Clinical and ccfDNA studies

Patients with unresectable, chemo-refractory colorectal cancer liver metastases (CRCLM) have limited local treatment options. We report our institutional experience on the efficacy of resin-based yttrium-90 (⁹⁰Y) radioembolization for the treatment of CRCLM and our findings on associated circulating cell-free DNA (ccfDNA) studies. A total of 58 patients treated with ⁹⁰Y for CRCLM at the Medstar Georgetown University Hospital had a median survival of 6 months [95% confidence interval (CI), 4.55–7.45 months] after treatment, with a 12-month survival rate of 33%. The median survival from treatment stratified by mutational status was longer in the wild-type (WT) as compared to the KRAS mutant patients at 7 vs. 5 months, but did not achieve statistical significance (p=0.059). Median tumor local control duration after ⁹⁰Y treatment was 2 months (95% CI, 0.34–3.66 months) for the entire cohort and was longer in the WT vs. the mutant patients (2 vs. 1 month, respectively, p=0.088). Plasma was prospectively collected from a subset of 9 patients both before and after single lobe treatment, and ccfDNA concentration and fragmentation index (FI) were measured using quantitative PCR and atomic-force microscopy (AFM). In the WT and KRAS mutant patients, DNA FI was reduced from a median of 0.73–0.65 after treatment. A reduction in DNA FI after single lobe treatment was associated with an improved overall survival (p=0.046). Analysis by AFM of paired pre- and post-treatment samples from KRAS mutant and WT patients revealed a larger average decrease in fragment size in the WT patients (p=0.013). ⁹⁰Y radioembolization extends local control for CRCLM, however, KRAS mutant tumors may be more radio-resistant to treatment. Changes in the FI of patients following treatment were noted and may be evaluated in a larger study for relevance as a biomarker of response.

Mechanisms of the induction of apoptosis mediated by radiation-induced cytokine release

The aim of the present work was to investigate the mechanisms of radiation-induced bystander signalling leading to apoptosis in non-irradiated co-cultured cells. Cultured non-transformed cells were irradiated, and the effect on the apoptosis rate on co-cultured non-irradiated malignant cells was determined. For this, two different levels of the investigation are presented, i.e. release of signalling proteins and transcriptomic profiling of the irradiated and non-irradiated co-cultured cells. Concerning the signalling proteins, in this study, the attention was focussed on the release of the active and latent forms of the transforming growth factor-β1 protein. Moreover, global gene expression profiles of non-transformed and transformed cells in untreated co-cultures were compared with those of 0.5-Gy-irradiated non-transformed cells co-cultured with the transformed cells. The results show an effect of radiation on the release of signalling proteins in the medium, although no significant differences in release rates were detectable when varying the doses in the range from 0.25 to 1 Gy. Moreover, gene expression results suggest an effect of radiation on both cell populations, pointing out specific signalling pathways that might be involved in the enhanced induction of apoptosis.

Chromatographische Fraktionierung und Trennung von Polystyrolen an Silicagel

Silica gel as a filler of separation columns fractionates and separates dissolved polystyrenes. Fractionation means: Continuous distribution of the polymeric homologues among the successive fractions of the eluate. Separation means: Discontinuous distribution. In both cases the polymeric homologues with higher molecular weights are transported more rapidly through the columns than the polymeric homologues with lower molecular weigths. Fractionation and separation of polystyrenes are based on characteristics of the space system within the silica gel particles. With equal dimensions of the columns fractionation and separation grow with the pore size of the silica gel particles.

Treatment of metastatic colorectal cancer with cetuximab: influence on the quality of life

BACKGROUND

Epidermal Growth Factor Receptor (EGFR) antibodies are innovative anti-cancer drugs prolonging survival in metastatic colocrectal cancer. However, due to adverse drug reactions, patients develop acneform skin toxicities. We hypothesized that the skin reaction leads to a decline in general (QOL) and dermatological health related quality of life (HQOL). Furthermore, we aimed at evaluating predictors for QOL and HQOL to improve individual adjustment of therapy.

METHODS

40 outpatients with metastatic colocrectal cancer were involved in this study. According to their KRAS status, patients were allocated to 2 groups: The CTCX group (n = 20; KRAS wild-type) was treated with the EGFR-antibody Cetuximab plus chemotherapy, the CT group (n = 20; KRAS mutation) was receiving chemotherapy only. Psychological assessment consisted of questionaires to evaluate QOL and HQOL, depression, coping-styles, health beliefs and the patient´s personality.

RESULTS

Between the two groups, no significanct difference in QOL was found, QOL remained stable over the course of treatment. Yet, the severity of the skin reactions had a significant influence on HQOL. Internal health beliefs and high compliance were found to be protective factors, while passive coping strategies, depression and the personality trait neuroticism were identified as risk factors.

DISCUSSION

Interdisciplinary cooperation between medical professionals and psycho-oncologists is strongly recommended to encourage patients to embark on and to retain EGFR-antibody therapy. If risk factors are present, psycho-oncological therapy should focus on the minimization of depression and on the development of active coping strategies.

Integrating research on thyroid cancer after Chernobyl--the Chernobyl Tissue Bank

The only unequivocal radiological effect of the Chernobyl accident on human health is the increase in thyroid cancer in those exposed in childhood or early adolescence. In response to the scientific interest in studying the molecular biology of thyroid cancer after Chernobyl, the Chernobyl Tissue Bank was established. The project is supported by the governments of Ukraine and Russia, and financially supported (in total around US$3 million) by the European Commission, the National Cancer Institute of the USA and the Sasakawa Memorial Health Foundation of Japan. The project began collecting a variety of biological samples from patients on 1 October 1988, and has supplied material to 21 research projects in Japan, the USA and Europe. The establishment of the Chernobyl Tissue Bank has facilitated co-operation between these research projects and the combination of clinical and research data provides a paradigm for cancer research in the molecular biological age.

[Chronic osteitis of the lower extremities. An interdisciplinary treatment concept]

INTRODUCTION

The purpose of this investigation was the retrospective analysis of patients with delayed infections, chronic posttraumatic osteitis of the lower extremities and free-flap coverage after radical debridement of bone and soft tissue.

METHODS

From the time period 1994-2003 a total of 22 patients including 4 females and 18 males were investigated. In 16 patients treatment was carried out on the lower leg and in 6 patients the foot was treated with subsequent free-flap coverage. In 14 cases the latissimus dorsi muscle was used, in 5 cases the gracilis muscle, in 2 cases parascapula flaps were used and in 1 case the serratus anterior muscle. The average age of the patients was 43 years (range 17-63 years) and grouping was according to the HOST classification. Functional outcome was evaluated by a standardized questionnaire (Funktionsfragebogen Hannover FFbH-OA 2,0), quality of life and social reintegration by non-standardized questionnaires.

RESULTS

In the cases investigated the following results could be achieved: full leg activity 55%, leg pain while walking 73%, special footwear 68%, normal gait 55%, positive quality of life and social reintegration 55%, port activities 36% and reemployment 45%.

CONCLUSION

According to the results of this study the quality of life of patients with chronic osteitis of the lower leg is in general satisfying. In order to improve quality management and cost reduction in public health an interdisciplinary treatment concept of plastic and orthopedic surgeons should be established for complex fracture management as this is the most effective tool in treating chronic osteitis.

Grade 3 Status Dominates Prognosis in Breast Cancer

Background: Histological grading (HG) is probably the most important clinico-pathological parameter that will provide information about tumour intrinsic characteristics and aggressiveness. HG is included in prognostic guidelines for treatment decision making such as St Gallen, Nottingham Prognostic Index and Adjuvant!Online. Grade 3 (G3) Breast cancer (BC) is associated with poor prognosis in terms of survival and recurrence. G3 BC reflects independent biological entities rather than being the end of the spectrum of cancer progression. Our aim is to establish the clinical relevance of HG as prognostic factor in a specific cohort of BC patients and define its relation with survival and recurrence endpoints.Method: This is a retrospective cohort analysis from 1489 operable Breast Cancer patients attending the Oncology Service at Singleton Hospital, Wales, UK between 1996 and 2002.HG was recorded for 1339 cases and outcome data were available on 1213 cases. Correlation of clinical variables with Overall Survival (OS), Distant Disease Free Survival (DDFS) and Disease Free Survival (DFS) was performed using Cox regression model.Results:The median follow-up for the cohort was 5.43 years (range 0.09 to 10.14 years) Patients were characterised according to age, HG, tumour size (TNM-T), nodal status, ER status and systemic treatment received (polychemotherapy/tamoxifen). Independent Cox regression models for each endpoint were developed based on univariate analyses. Multivariate analysis results are presented in Figure 1.Subgroup analysis of G3 cases showed a younger population: median age G3 59.4y vs G1/G2 62.9 y p:&lt; 0.001); 47.5% of G3 cases were ER positive against 94.5% of Grade 1/2 (p &lt; 0.001). Patients with G3 tumours died more rapidly from all causes (median time to death 2.22 vs 3.42 y, p &lt;0.001) and from BC (median time to death from BC 2.22 y vs 3.82 y in G1/G2, p &lt;0.001) than other HG. Similarly, G3 also relapsed quicker both distantly, (median time 1.64 vs 2.54 y G1/G2 (p&lt;0.04) and locally, median time to relapse 1.6 vs 2.35 y for G1/G2 (p&lt;0.036). There was also a significant association between grade and tumour size (median G1/G2 1.7cm vs G3 2.2cm(p&lt; 0.001); and nodal involvement and tumour size, median 1.5cm N-ve, 2.2 cm N+ve (p&lt; 0.001).Conclusion: Patients with G3 tumours tended to be younger, had a more advanced TNM staging at diagnosis and relapsed and died more rapidly than other histological grades. In our cohort, G3 tumours were adversely associated with OS, DDFS and DFS with a stronger association with these endpoints than node positivity. It is perhaps time to reconsider the HG as a prognostic factor as important as nodal status for the selection of adjuvant chemotherapy regimens.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6005.

Molecular Heterogeneity of Grade 3 Breast Cancer

Background: Histological grade (HG) is one the main prognostic factors used in clinical practice, along with nodal status and tumour size, for the classification of patients into different prognostic groups that support the clinical decision making process and to tailor adjuvant treatment according to specific risk of death or relapse. The aim of this study was to examine the effect of Grade in prognosis in an unselected series of breast cancers, and to examine copy number alteration (CNA) specifically in Grade 3 (G3) breast cancer and its relationship to nodal status (N-ve/N+ve) and clinical outcome, to seek genetically determined markers of prognosis for treatment tailoring in this poor prognosis group.Method: We established a clinical database of 1489 operable Breast Cancer patients attending the Oncology Service at Singleton Hospital, Wales, UK between 1996 and 2002. HG was known for 1339 of these cases, and outcome in 1213, with a median of 5.32 years (range 0.09 - 10.14 years) follow-up. From the 466 G3 cases of primary breast cancer, we analysed 81 cases using 1Mb BAC array CGH for genomic copy number alterations. Spatial normalisation, circular binary segmentation and the CGHcall algorithm was used to generate CGH profiles. Unsupervised hierarchical clustering, supervised, correlation and survival analyses were carried out using packages and tests within the R statistical platform.Results: Patients were characterised according to grade, ER and nodal status. Kaplan Meier analysis for overall survival (OS) and disease specific survival (DFS) confirmed the poor prognosis of G3 (Cox proportional hazards regression, Wald-test p-value &lt;&lt; 0.05). The majority of G1 (98%) and G2 (93%) cases were ER +ve, whereas 52.5% G3 cases were ER-ve. ER status was known for 316 of the 466 G3 cases, and ER negativity was significantly associated with a decreased OS (p-value 0.02), but not DFS (p-value: 0.13). Similarly N+vity also showed significant correlation with both OS and DFS (p-values &lt; 0.05). BAC aCGH analysis showed significant copy number gains on chromosomes 1,4,5,7,11 and 21 in N+ve and losses on chromosomes 1,6 and 10 in N-ve G3. One region of chromosome 1 (1p36 – 1p35) in particular was lost in N0 but gained in N+ve, and this was significantly associated with ER-ve/N+ve cases (FDR p-value &lt; 0.05). BAC aCGH profiles did not significantly associate with ER status in G3 disease. Two clusters, delineated on unsupervised hierarchical cluster analysis, correlated with OS. Neither correlated with nodal or ER status, indicating that further analysis may discover genes of prognostic potential within these profiles.Conclusion HG was significantly associated with clinical outcome and ER status. Genomic copy number analysis (CNA) in G3 breast cancer revealed significant associations between DNA alterations and nodal status and OS. The study is currently being extended to investigate the relationship between specific CNA and clinical outcome in G3 disease.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5167.

RET rearrangements in post-Chernobyl papillary thyroid carcinomas with a short latency analysed by interphase FISH

Tissue samples from 13 post-Chernobyl childhood thyroid tumours that occurred within a short period of time (4–8 years) after the Chernobyl accident have been investigated by interphase FISH analysis for rearrangements of RET. In all, 77% of cases showed RET/PTC rearrangements and a distinct intratumoural genetic heterogeneity. The data were compared to findings on 32 post-Chernobyl PTCs that occurred after a longer period of time (9–12 years) after the accident. In none of the cases from either group were 100% of cells positive for RET rearrangement. In addition, the pattern of RET-positive cells was different in the two groups (short vs longer latency). A significant clustering of aberrant cells could be detected in the long-latency subgroup, whereas the aberrant cells were more homogeneously distributed among the short-latency tumours. The findings suggest that oligoclonal tumour development occurs in post-Chernobyl PTCs. This pattern of different clones within the tumour appears to become more discrete in cases with longer latencies, suggesting either outgrowth of individual clones or development of later subclones with time.