Indkomne bøger fra oktober 1999 til september 2000

Head and neck cancer (HNC) has a high incidence in Brazil, with cancer of the oral cavity being one of the five most common cancers among Brazilians. Alcohol and tobacco consumption may contribute to synchronous or metachronous HNC and esophageal cancer. The early detection of superficial esophageal cancer and dysplasia in asymptomatic patients with HNC, after successfully treating the primary cancer, may provide an effective cure. A prospective study involving 60 patients with HNC was carried out at the State University of Campinas (UNICAMP) to screen for superficial esophageal cancer and dysplasia using endoscopy and a 2% lugol dye solution followed by biopsy of the suspicious areas. Five patients (8.3%) had superficial esophageal cancer, which was diagnosed as intraepithelial carcinoma in three of them (5.0%). In four patients, the superficial esophageal cancer was synchronous, and in one it was metachronous to HNC. Five patients (8.3%) had dysplasias in the esophageal epithelium (three were classified as mild and two as moderate). These results demonstrate the value of endoscopic screening of the esophagus using lugol dye in patients with HNC, particularly because superficial esophageal cancer is extremely difficult to detect by conventional methods in asymptomatic patients.22170-

First observation of low energy electron neutrinos in a liquid argon time projection chamber

Citation: Acciarri, R., Adams, C., Asaadi, J., Baller, B., Bolton, T., Bromberg, C., . . . ArgoNeu, T. C. (2017). First observation of low energy electron neutrinos in a liquid argon time projection chamber. Physical Review D, 95(7), 15. doi:10.1103/PhysRevD.95.072005The capabilities of liquid argon time projection chambers (LArTPCs) to reconstruct the spatial and calorimetric information of neutrino events have made them the detectors of choice in a number of experiments, specifically those looking to observe electron neutrino (nu(e)) appearance. The LArTPC promises excellent background rejection capabilities, especially in this "golden" channel for both short and long baseline neutrino oscillation experiments. We present the first experimental observation of electron neutrinos and antineutrinos in the ArgoNeut LArTPC, in the energy range relevant to DUNE and the Fermilab Short Baseline Neutrino Program. We have selected 37 electron candidate events and 274 gamma candidate events, and measured an 80% purity of electrons based on a topological selection. Additionally, we present a separation of electrons from gammas using calorimetric energy deposition, demonstrating further separation of electrons from background gammas

Improved Limits on Millicharged Particles Using the ArgoNeuT Experiment at Fermilab

A search for millicharged particles, a simple extension of the standard model, has been performed with the ArgoNeuT detector exposed to the Neutrinos at the Main Injector beam at Fermilab. The ArgoNeuT Liquid Argon Time Projection Chamber detector enables a search for millicharged particles through the detection of visible electron recoils. We search for an event signature with two soft hits (MeV-scale energy depositions) aligned with the upstream target. For an exposure of the detector of $1.0$ $\times$ $10^{20}$ protons on target, one candidate event has been observed, compatible with the expected background. This search is sensitive to millicharged particles with charges between $10^{-3}e$ and $10^{-1}e$ and with masses in the range from $0.1$ GeV to $3$ GeV. This measurement provides leading constraints on millicharged particles in this large unexplored parameter space region.Comment: Version accepted by PR

First Measurement of Electron Neutrino Scattering Cross Section on Argon

We report the first electron neutrino cross section measurements on argon, based on data collected by the ArgoNeuT experiment running in the GeV-scale NuMI beamline at Fermilab. A flux-averaged $\nu_e + \overline{\nu}_e$ total and a lepton angle differential cross section are extracted using 13 $\nu_e$ and $\overline{\nu}_e$ events identified with fully-automated selection and reconstruction. We employ electromagnetic-induced shower characterization and analysis tools developed to identify $\nu_e/\overline{\nu}_e$-like events among complex interaction topologies present in ArgoNeuT data ($\langle E_{\bar{\nu}_e} \rangle = 4.3$ GeV and $\langle E_{\nu_e} \rangle = 10.5$ GeV). The techniques are widely applicable to searches for electron-flavor appearance at short- and long-baseline using liquid argon time projection chamber technology. Notably, the data-driven studies of GeV-scale $\nu_e/\overline{\nu}_e$ interactions presented in this Letter probe an energy regime relevant for future DUNE oscillation physics.Comment: added acknowledgement

First measurement of the cross section for νμ\nu_\mu and νˉμ\bar{\nu}_\mu induced single charged pion production on argon using ArgoNeuT

We report on the first cross section measurement of charged-current single charged pion production by neutrinos and antineutrinos on argon. This analysis was performed using the ArgoNeuT detector exposed to the NuMI beam at Fermilab. The measurements are presented as functions of muon momentum, muon angle, pion angle, and angle between muon and pion. The flux-averaged cross sections are measured to be $2.7\pm0.5(stat)\pm0.5(syst) \times 10^{-37} \textrm{cm}^{2}/\textrm{Ar}$ for neutrinos at a mean energy of 9.6 GeV and $8.4\pm0.9(stat)^{+1.0}_{-0.8}(syst) \times 10^{-38} \textrm{cm}^{2}/\textrm{Ar}$ for antineutrinos at a mean energy of 3.6 GeV with the charged pion momentum above 100 MeV/$c$. The results are compared with several model predictions

Mutation spectrum of 122 hemophilia A families from Taiwanese population by LD-PCR, DHPLC, multiplex PCR and evaluating the clinical application of HRM

<p>Abstract</p> <p>Background</p> <p>Hemophilia A represents the most common and severe inherited hemorrhagic disorder. It is caused by mutations in the F8 gene, which leads to a deficiency or dysfunctional factor VIII protein, an essential cofactor in the factor X activation complex.</p> <p>Methods</p> <p>We used long-distance polymerase chain reaction and denaturing high performance liquid chromatography for mutation scanning of the F8 gene. We designed the competitive multiplex PCR to identify the carrier with exonal deletions. In order to facilitate throughput and minimize the cost of mutation scanning, we also evaluated a new mutation scanning technique, high resolution melting analysis (HRM), as an alternative screening method.</p> <p>Results</p> <p>We presented the results of detailed screening of 122 Taiwanese families with hemophilia A and reported twenty-nine novel mutations. There was one family identified with whole exons deletion, and the carriers were successfully recognized by multiplex PCR. By HRM, the different melting curve patterns were easily identified in 25 out of 28 cases (89%) and 15 out of 15 (100%) carriers. The sensitivity was 93 % (40/43). The overall mutation detection rate of hemophilia A was 100% in this study.</p> <p>Conclusion</p> <p>We proposed a diagnostic strategy for hemophilia A genetic diagnosis. We consider HRM as a powerful screening tool that would provide us with a more cost-effective protocol for hemophilia A mutation identification.</p

Rejecting cosmic background for exclusive neutrino interaction studies with Liquid Argon TPCs; a case study with the MicroBooNE detector

Cosmic ray (CR) interactions can be a challenging source of background for neutrino oscillation and cross-section measurements in surface detectors. We present methods for CR rejection in measurements of charged-current quasielastic-like (CCQE-like) neutrino interactions, with a muon and a proton in the final state, measured using liquid argon time projection chambers (LArTPCs). Using a sample of cosmic data collected with the MicroBooNE detector, mixed with simulated neutrino scattering events, a set of event selection criteria is developed that produces an event sample with minimal contribution from CR background. Depending on the selection criteria used a purity between 50% and 80% can be achieved with a signal selection efficiency between 50% and 25%, with higher purity coming at the expense of lower efficiency. While using a specific dataset from the MicroBooNE detector and selection criteria values optimized for CCQE-like events, the concepts presented here are generic and can be adapted for various studies of exclusive {\nu}{\mu} interactions in LArTPCs.Comment: 12 pages, 10 figures, 1 tabl

First Measurement of νμ\nu_{\mu} Charged-Current π0\pi^{0} Production on Argon with a LArTPC

We report the first measurement of the flux-integrated cross section of $\nu_{\mu}$ charged-current single $\pi^{0}$ production on argon. This measurement is performed with the MicroBooNE detector, an 85 ton active mass liquid argon time projection chamber exposed to the Booster Neutrino Beam at Fermilab. This result on argon is compared to past measurements on lighter nuclei to investigate the scaling assumptions used in models of the production and transport of pions in neutrino-nucleus scattering. The techniques used are an important demonstration of the successful reconstruction and analysis of neutrino interactions producing electromagnetic final states using a liquid argon time projection chamber operating at the earth's surface