Leptonic and Semileptonic Decays of Charm and Bottom Hadrons

We review the experimental measurements and theoretical descriptions of leptonic and semileptonic decays of particles containing a single heavy quark, either charm or bottom. Measurements of bottom semileptonic decays are used to determine the magnitudes of two fundamental parameters of the standard model, the Cabibbo-Kobayashi-Maskawa matrix elements $V_{cb}$ and $V_{ub}$. These parameters are connected with the physics of quark flavor and mass, and they have important implications for the breakdown of CP symmetry. To extract precise values of $|V_{cb}|$ and $|V_{ub}|$ from measurements, however, requires a good understanding of the decay dynamics. Measurements of both charm and bottom decay distributions provide information on the interactions governing these processes. The underlying weak transition in each case is relatively simple, but the strong interactions that bind the quarks into hadrons introduce complications. We also discuss new theoretical approaches, especially heavy-quark effective theory and lattice QCD, which are providing insights and predictions now being tested by experiment. An international effort at many laboratories will rapidly advance knowledge of this physics during the next decade.Comment: This review article will be published in Reviews of Modern Physics in the fall, 1995. This file contains only the abstract and the table of contents. The full 168-page document including 47 figures is available at http://charm.physics.ucsb.edu/papers/slrevtex.p

Molecular Structure of Amyloid Fibrils Controls the Relationship between Fibrillar Size and Toxicity

According to the prevailing view, soluble oligomers or small fibrillar fragments are considered to be the most toxic species in prion diseases. To test this hypothesis, two conformationally different amyloid states were produced from the same highly pure recombinant full-length prion protein (rPrP). The cytotoxic potential of intact fibrils and fibrillar fragments generated by sonication from these two states was tested using cultured cells.For one amyloid state, fibril fragmentation was found to enhance its cytotoxic potential, whereas for another amyloid state formed within the same amino acid sequence, the fragmented fibrils were found to be substantially less toxic than the intact fibrils. Consistent with the previous studies, the toxic effects were more pronounced for cell cultures expressing normal isoform of the prion protein (PrP(C)) at high levels confirming that cytotoxicity was in part PrP(C)-dependent. Silencing of PrP(C) expression by small hairpin RNAs designed to silence expression of human PrP(C) (shRNA-PrP(C)) diminished the deleterious effects of the two amyloid states to a different extent, suggesting that the role of PrP(C)-mediated and PrP(C)-independent mechanisms depends on the structure of the aggregates.This work provides a direct illustration that the relationship between an amyloid's physical dimension and its toxic potential is not unidirectional but is controlled by the molecular structure of prion protein (PrP) molecules within aggregated states. Depending on the structure, a decrease in size of amyloid fibrils can either enhance or abolish their cytotoxic effect. Regardless of the molecular structure or size of PrP aggregates, silencing of PrP(C) expression can be exploited to reduce their deleterious effects

Combining Congenital Heart Surgical and Interventional Cardiology Outcome Data in a Single Database: The Development of a Patient-Centered Collaboration of the European Congenital Heart Surgeons Association (ECHSA) and the Association for European Paediatric and Congenital Cardiology (AEPC)

The European Congenital Heart Surgeons Association (ECHSA) Congenital Database (CD) is the second largest clinical pediatric and congenital cardiac surgical database in the world and the largest in Europe, where various smaller national or regional databases exist. Despite the dramatic increase in interventional cardiology procedures over recent years, only scattered national or regional databases of such procedures exist in Europe. Most importantly, no congenital cardiac database exists in the world that seamlessly combines both surgical and interventional cardiology data on an international level; therefore, the outcomes of surgical and interventional procedures performed on the same or similar patients cannot easily be tracked, assessed, and analyzed. In order to fill this important gap in our capability to gather and analyze information on our common patients, ECHSA and The Association for European Paediatric and Congenital Cardiology (AEPC) have embarked on a collaborative effort to expand the ECHSA-CD with a new module designed to capture data about interventional cardiology procedures. The purpose of this manuscript is to describe the concept, the structure, and the function of the new AEPC Interventional Cardiology Part of the ECHSA-CD, as well as the potentially valuable synergies provided by the shared interventional and surgical analyses of outcomes of patients. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow centers to have access to robust surgical and transcatheter outcome data from their own center, as well as robust national and international aggregate outcome data for benchmarking. Each contributing center or department will have access to their own data, as well as aggregate data from the AEPC Interventional Cardiology Part of the ECHSA-CD. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow cardiology centers to have access to aggregate cardiology data, just as surgical centers already have access to aggregate surgical data. Comparison of surgical and catheter interventional outcomes could potentially strengthen decision processes. A study of the wealth of information collected in the database could potentially also contribute toward improved early and late survival, as well as enhanced quality of life of patients with pediatric and/or congenital heart disease treated with surgery and interventional cardiac catheterization across Europe and the world

Combining Congenital Heart Surgical and Interventional Cardiology Outcome Data in a Single Database: The Development of a Patient-Centered Collaboration of the European Congenital Heart Surgeons Association (ECHSA) and the Association for European Paediatric and Congenital Cardiology (AEPC)

The European Congenital Heart Surgeons Association (ECHSA) Congenital Database (CD) is the second largest clinical pediatric and congenital cardiac surgical database in the world and the largest in Europe, where various smaller national or regional databases exist. Despite the dramatic increase in interventional cardiology procedures over recent years, only scattered national or regional databases of such procedures exist in Europe. Most importantly, no congenital cardiac database exists in the world that seamlessly combines both surgical and interventional cardiology data on an international level; therefore, the outcomes of surgical and interventional procedures performed on the same or similar patients cannot easily be tracked, assessed, and analyzed. In order to fill this important gap in our capability to gather and analyze information on our common patients, ECHSA and The Association for European Paediatric and Congenital Cardiology (AEPC) have embarked on a collaborative effort to expand the ECHSA-CD with a new module designed to capture data about interventional cardiology procedures. The purpose of this manuscript is to describe the concept, the structure, and the function of the new AEPC Interventional Cardiology Part of the ECHSA-CD, as well as the potentially valuable synergies provided by the shared interventional and surgical analyses of outcomes of patients. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow centers to have access to robust surgical and transcatheter outcome data from their own center, as well as robust national and international aggregate outcome data for benchmarking. Each contributing center or department will have access to their own data, as well as aggregate data from the AEPC Interventional Cardiology Part of the ECHSA-CD. The new AEPC Interventional Cardiology Part of the ECHSA-CD will allow cardiology centers to have access to aggregate cardiology data, just as surgical centers already have access to aggregate surgical data. Comparison of surgical and catheter interventional outcomes could potentially strengthen decision processes. A study of the wealth of information collected in the database could potentially also contribute toward improved early and late survival, as well as enhanced quality of life of patients with pediatric and/or congenital heart disease treated with surgery and interventional cardiac catheterization across Europe and the world

Direct measurement of the phi(1020) leptonic branching ratio

The process e+e-->mu+mu- has been studied by SND detector at VEPP-2M e+e- collider in the phi(1020)-resonance energy region. The measured effective phi meson leptonic branching ratio: B(phi->l+l-)=sqrt{B(phi->e+e-)*B(phi->mu+mu-)}=(2.89+-0.10+-0.06)*10^{-4} agrees well with the PDG value B(phi->e+e-)=(2.91+-0.07)*10^{-4} confirming mu-e universality. Without additional assumption of mu-e universality the branching ratio B(phi->mu+mu-)=(2.87+-0.20+-0.14)*10^{-4} was obtained.Comment: RevTeX, 5 pages, 3 figures. To be published in Phys. Rev. Let

Measurement of \chi_{c2} Production in Two-Photon Collisions

The production of the \chi_{c2} charmonium state in two-photon collisions has been measured with the Belle detector at the KEKB e^+e^- collider. A clear signal for \chi_{c2} --> \gamma J/\psi, J/\psi --> l^+l^- is observed in a 32.6fb^{-1} data sample accumulated at center-of-mass energies near 10.6GeV, and the product of its two-photon decay width and branching fraction is determined to be \Gamma_{\gamma\gamma}(\chi_{c2})B(\chi_{c2} --> \gamma J/\psi) B(J/\psi --> l^+l^-)= 13.5 +/- 1.3(stat.) +/- 1.1(syst.)eV.Comment: 16 pages, 5 figures, to be submitted to Phys. Lett.

Precison Measurements of the Mass, the Widths of ψ(3770)\psi(3770) Resonance and the Cross Section σ[e+e−→ψ(3770)]\sigma[e^+e^-\to \psi(3770)] at Ecm=3.7724E_{\rm cm}=3.7724 GeV

By analyzing the $R$ values measured at 68 energy points in the energy region between 3.650 and 3.872 GeV reported in our previous paper, we have precisely measured the mass, the total width, the leptonic width and the leptonic decay branching fraction of the $\psi(3770)$ to be ${M}_{\psi(3770)}=3772.4 \pm 0.4 \pm 0.3$ MeV, $\Gamma_{\psi(3770)}^{\rm tot} = 28.6 \pm 1.2 \pm 0.2$ MeV, $\Gamma_{\psi(3770)}^{ee} = 279 \pm 11 \pm 13$ eV and $B[\psi(3770)\to e^+e^-]=(0.98\pm 0.04\pm 0.04)\times 10^{-5}$, respectively, which result in the observed cross section $\sigma^{\rm obs}[e^+e^-\to \psi(3770)]=7.25\pm 0.27 \pm 0.34$ nb at $\sqrt{s}=3772.4$ MeV. We have also measured $R_{\rm uds}=2.121\pm 0.023 \pm 0.084$ for the continuum light hadron production in the region from 3.650 to 3.872 GeV.Comment: 5 pages, 2 figure

Search for eta_b in two-photon collisions at LEP II with the DELPHI detector

The pseudoscalar meson eta_b has been searched for in two-photon interactions at LEP II. The data sample corresponds to a total integrated luminosity of 617 pb^{-1} at centre-of-mass energies ranging from 161 to 209 GeV. Upper limits at a confidence level of 95% on the product Gamma_{\gamma\gamma}(eta_b) x BR(eta_b) are 190, 470 and 660 eV/c^2 for the eta_b decaying into 4, 6 and 8 charged particles, respectively.Comment: 11 pages, 3 figures, Accepted by Phys. Lett.

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

© 2024 The Authors. Journal of Extracellular Vesicles, published by Wiley Periodicals, LLC on behalf of the International Society for Extracellular Vesicles. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.Peer reviewe