29 research outputs found
First observation of the decays ÏcJâÏ0Ï0Ï0Ï0
We present a study of the P-wave spin-triplet charmonium Ï cJ decays (J=0, 1, 2) into Ï0Ï0Ï0Ï0. The analysis is based on 106Ă106 ÏââČ decays recorded with the BESIII detector at the BEPCII electron positron collider. The decay into the Ï0Ï0Ï0Ï0 hadronic final state is observed for the first time. We measure the branching fractions B(Ï c0âÏ0Ï0Ï0Ï0)=(3.34±0. 06±0.44)Ă10â-3, B(Ï c1âÏ0Ï0Ï0Ï0) =(0.57±0.03±0.08)Ă10â-3, and B(Ï c2âÏ0Ï0Ï0Ï0)=(1.21±0.05±0.16) Ă10â-3, where the uncertainties are statistical and systematical, respectively. © 2011 American Physical Society.published_or_final_versio
Measurement of the matrix element for the decay ηâČâÎ·Ï +Ï -
The Dalitz plot of ηââČâηÏâ+Ïâ- decay is studied using (225.2±2.8)Ă106 J/Ï events collected with the BESIII detector at the BEPCII eâ+eâ- collider. With the largest sample of ηââČ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/ÏâγηââČ is determined to be (4.84±0.03±0.24)Ă10â-3, where the first error is statistical and the second systematic. © 2011 American Physical Society.published_or_final_versio
Study of a00(980)-f0(980) mixing
Using samples of 2.25Ă108 J/Ï events and 1.06Ă108 Ï âČ events collected with the BES III detector, we study the f 0(980)âa00(980) and a00(980)âf 0(980) transitions in the processes J/ÏâÏf 0(980) âÏa00(980) and Ï c1âÏ0a00(980)âÏ0f 0(980), respectively. Evidence for f 0(980)âa00(980) is found with a significance of 3.4Ï, while in the case of a00(980)âf 0(980) transition, the significance is 1.9Ï. Measurements and upper limits of both branching ratios and mixing intensities are determined. © 2011 American Physical Society.published_or_final_versio
Observation of \chi_{cJ} decaying into the p\bar{p}K^{+}K^{-} final state
First measurements of the decays of the three states to
final states are presented. Intermediate and resonance states are observed, and
branching fractions for ,
, and are reported. We also
measure branching fractions for direct
decays. These are first observations of decays to unstable baryon
resonances and provide useful information about the states. The
experiment uses samples of mesons produced via radiative
transitions from 106 million mesons collected in the BESIII
detector at the BEPCII collider.Comment: 16 pages, 5 figure
Evidence for psi' decays into gamma pi^0 and gamma eta
The decays psi'->gamma pi^0, gamma eta and gamma eta' are studied using data
collected with the BESIII detector at the BEPCII e^+e^- collider. Processes
psi'->gamma pi^0 and psi'->gamma eta are observed for the first time with
signal significances of 4.6 sigma and 4.3 sigma, respectively. The branching
fractions are determined to be: B(psi'->gamma pi^0)=(1.58+-0.40+-0.13)x10^{-6},
B(psi'->gamma eta)=(1.38+-0.48+-0.09)x10^{-6}, and B(psi'->gamma
eta')=(126+-3+-8) x 10^{-6}, where the first errors are statistical and the
second ones systematic.Comment: 6 pages, 4 figure
Advances in structure elucidation of small molecules using mass spectrometry
The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules
Pan-cancer analysis of whole genomes
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe
Comprehensive molecular characterization of the hippo signaling pathway in cancer
Hippo signaling has been recognized as a key tumor suppressor pathway. Here, we perform a comprehensive molecular characterization of 19 Hippo core genes in 9,125 tumor samples across 33 cancer types using multidimensional âomicâ data from The Cancer Genome Atlas. We identify somatic drivers among Hippo genes and the related microRNA (miRNA) regulators, and using functional genomic approaches, we experimentally characterize YAP and TAZ mutation effects and miR-590 and miR-200a regulation for TAZ. Hippo pathway activity is best characterized by a YAP/TAZ transcriptional target signature of 22 genes, which shows robust prognostic power across cancer types. Our elastic-net integrated modeling further reveals cancer-type-specific pathway regulators and associated cancer drivers. Our results highlight the importance of Hippo signaling in squamous cell cancers, characterized by frequent amplification of YAP/TAZ, high expression heterogeneity, and significant prognostic patterns. This study represents a systems-biology approach to characterizing key cancer signaling pathways in the post-genomic era