46 research outputs found

    Search for right-handed W bosons in top quark decay

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    We present a measurement of the fraction f+ of right-handed W bosons produced in top quark decays, based on a candidate sample of ttˉt\bar{t} events in the lepton+jets decay mode. These data correspond to an integrated luminosity of 230pb^-1, collected by the DO detector at the Fermilab Tevatron ppˉp\bar{p} Collider at sqrt(s)=1.96 TeV. We use a constrained fit to reconstruct the kinematics of the ttˉt\bar{t} and decay products, which allows for the measurement of the leptonic decay angle θ\theta^* for each event. By comparing the cosθ\cos\theta^* distribution from the data with those for the expected background and signal for various values of f+, we find f+=0.00+-0.13(stat)+-0.07(syst). This measurement is consistent with the standard model prediction of f+=3.6x10^-4.Comment: Submitted to Physical Review D Rapid Communications 7 pages, 3 figure

    Met-Independent Hepatocyte Growth Factor-mediated regulation of cell adhesion in human prostate cancer cells

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    BACKGROUND: Prostate cancer cells communicate reciprocally with the stromal cells surrounding them, inside the prostate, and after metastasis, within the bone. Each tissue secretes factors for interpretation by the other. One stromally-derived factor, Hepatocyte Growth Factor (HGF), was found twenty years ago to regulate invasion and growth of carcinoma cells. Working with the LNCaP prostate cancer progression model, we found that these cells could respond to HGF stimulation, even in the absence of Met, the only known HGF receptor. The new HGF binding partner we find on the cell surface may help to clarify conflicts in the past literature about Met expression and HGF response in cancer cells. METHODS: We searched for Met or any HGF binding partner on the cells of the PC3 and LNCaP prostate cancer cell models, using HGF immobilized on agarose beads. By using mass spectrometry analyses and sequencing we have identified nucleolin protein as a novel HGF binding partner. Antibodies against nucleolin (or HGF) were able to ameliorate the stimulatory effects of HGF on met-negative prostate cancer cells. Western blots, RT-PCR, and immunohistochemistry were used to assess nucleolin levels during prostate cancer progression in both LNCaP and PC3 models. RESULTS: We have identified HGF as a major signaling component of prostate stromal-conditioned media (SCM) and have implicated the protein nucleolin in HGF signal reception by the LNCaP model prostate cancer cells. Antibodies that silence either HGF (in SCM) or nucleolin (on the cell surfaces) eliminate the adhesion-stimulatory effects of the SCM. Likewise, addition of purified HGF to control media mimics the action of SCM. C4-2, an LNCaP lineage-derived, androgen-independent human prostate cancer cell line, responds to HGF in a concentration-dependent manner by increasing its adhesion and reducing its migration on laminin substratum. These HGF effects are not due to shifts in the expression levels of laminin-binding integrins, nor can they be linked to expression of the known HGF receptor Met, as neither LNCaP nor clonally-derived C4-2 sub-line contain any detectable Met protein. Even in the absence of Met, small GTPases are activated, linking HGF stimulation to membrane protrusion and integrin activation. Membrane-localized nucelolin levels increase during cancer progression, as modeled by both the PC3 and LNCaP prostate cancer progression cell lines. CONCLUSION: We propose that cell surface localized nucleolin protein may function in these cells as a novel HGF receptor. Membrane localized nucleolin binds heparin-bound growth factors (including HGF) and appears upregulated during prostate cancer progression. Antibodies against nucleolin are able to ameliorate the stimulatory effects of HGF on met-negative prostate cancer cells. HGF-nucleolin interactions could be partially responsible for the complexity of HGF responses and met expression reported in the literature

    Pretreatment neutrophil to lymphocyte and platelet to lymphocyte ratios as predictive factors for the survival of cervical adenocarcinoma patients

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    Joanna Jonska-Gmyrek,1 Leszek Gmyrek,2 Agnieszka Zolciak-Siwinska,3 Maria Kowalska,4 Malgorzata Fuksiewicz,4 Beata Kotowicz4 1Department of Uro-oncology, Maria Sklodowska-Curie Institute – Oncology Center, Warsaw 02-781, Poland; 2Department of Gynecological Oncology, The Holy Family Hospital, Warsaw 02-544, Poland; 3Department of Brachytherapy, Maria Sklodowska-Curie Institute – Oncology Center, Warsaw 02-781, Poland; 4Laboratory of Tumor Markers, Department of Pathology and Laboratory Diagnostics, Maria Sklodowska-Curie Institute – Oncology Center, Warsaw 02-781, Poland Objective: Our study assessed the clinical utility and prognostic value of pretreatment hematological parameters and calculated coefficients including the platelet to lymphocyte ratio (PLR), neutrophil to lymphocyte ratio (NLR), and monocyte to lymphocyte ratio (MLR) in patients with cervical adenocarcinoma (CA).Materials and methods: Among 738 cervical cancer patients with International Federation of Gynecology and Obstetrics (FIGO) stages IA–IV treated at our institution, 96 (13%) presented with CA histology. The blood samples, collected within 10 days before treatment, were analyzed using a Sysmex XN-2000 system. The statistical tests included Mann–Whitney U-tests, log-rank tests, and Cox regression models. The cutoff points for the calculated hematological coefficients (NLR, PLR, and MLR) were determined using the MedCalc statistical program.Results: The prognostic factor for overall survival (OS) and recurrence-free survival (RFS) in CA was clinical stage according to FIGO classification (FIGO IIB–IV vs I–IIA) (P=0.0001; P=0.002). Among patients with FIGO stage IIB–IV treated with radiotherapy/chemoradiotherapy, an elevated PLR was a negative prognostic factor for OS (P=0.017; HR: 2.96; 95% CI: 2.069–3.853). Among all patients, an elevated pretreatment NLR was a poor prognostic factor for OS (P=0.014; HR: 2.85; 95% CI: 2.011–3.685) and RFS (P=0.049; HR: 4.0; 95% CI: 2.612–5.392). The white blood cell count (WBC) before treatment was significantly higher in patients who died during follow-up (P=0.009).Conclusion: Elevated NLR values before treatment may be associated with a shorter time of RFS and OS, while PLR index may have prognostic significance for OS in patients with advanced disease (FIGO IIB–IV). Both indexes and WBC may be a cost-effective biomarker that can be used conveniently for stratification of recurrence risk and death. Keywords: platelet to lymphocyte ratio, cervical cancer, neutrophil to lymphocyte ratio, prognostic factor

    Spatial MMF Harmonic Mitigation in Aluminum-Cage Induction Motors

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    This study investigates the effects of the spatial harmonics of magneto-motive force that appear in the air-gap of aluminum-cage induction motors, proposing some techniques for their mitigation. With respect to previous researches, special magnetic wedges to be mounted in the stator opening regions of semi-closed slots of existing motors are proposed, together with a special winding layout having a very low magnetomotive force harmonic content. Both 2D- and 3D-FEM numerical simulations have been carried out to quantify the problems and to understand the potential benefits of inserting the stator wedges. At the end, the mechanical feasibility of the proposed wedges is considered together with some attempts at implementation
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