551 research outputs found

    Estimation of the material budget of the Inner Tracker

    Get PDF
    The material budget of the LHCb Inner Tracker in July 2008 is estimated. Values are also given for the total material before the magnet and integrated to RICH 2

    Modulation of PKM alternative splicing by PTBP1 promotes gemcitabine resistance in pancreatic cancer cells

    Get PDF
    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and incurable disease. Poor prognosis is due to multiple reasons, including acquisition of resistance to gemcitabine, the first-line chemotherapeutic approach. Thus, there is a strong need for novel therapies, targeting more directly the molecular aberrations of this disease. We found that chronic exposure of PDAC cells to gemcitabine selected a subpopulation of cells that are drug-resistant (DR-PDAC cells). Importantly, alternative splicing (AS) of the pyruvate kinase gene (PKM) was differentially modulated in DR-PDAC cells, resulting in promotion of the cancer-related PKM2 isoform, whose high expression also correlated with shorter recurrence-free survival in PDAC patients. Switching PKM splicing by antisense oligonucleotides to favor the alternative PKM1 variant rescued sensitivity of DR-PDAC cells to gemcitabine and cisplatin, suggesting that PKM2 expression is required to withstand drug-induced genotoxic stress. Mechanistically, upregulation of the polypyrimidine-tract binding protein (PTBP1), a key modulator of PKM splicing, correlated with PKM2 expression in DR-PDAC cell lines. PTBP1 was recruited more efficiently to PKM pre-mRNA in DR- than in parental PDAC cells. Accordingly, knockdown of PTBP1 in DR-PDAC cells reduced its recruitment to the PKM pre-mRNA, promoted splicing of the PKM1 variant and abolished drug resistance. Thus, chronic exposure to gemcitabine leads to upregulation of PTBP1 and modulation of PKM AS in PDAC cells, conferring resistance to the drug. These findings point to PKM2 and PTBP1 as new potential therapeutic targets to improve response of PDAC to chemotherapy.Oncogene advance online publication, 3 August 2015; doi:10.1038/onc.2015.270

    Diagnosis and treatment of acute pancreatitis: The position statement of the Italian Association for the study of the pancreas

    Get PDF
    BACKGROUND AND AIM: Till now, no Italian studies providing information on acute pancreatitis have been published. The aim of this study was to evaluate the epidemiological and clinical characteristics of acute pancreatitis in Italy. MATERIALS AND METHODS: The study involved 37 Italian centres distributed homogeneously throughout the entire national territory and prospectively collected epidemiological, anamnestic, laboratory, radiological, therapeutic (pharmacological, endoscopic and surgical) data, relevant to each individual case of acute pancreatitis consecutively observed during the period from September 1996 to June 2000. RESULTS: One thousand two hundred and six case report forms were collected, but 201 patients (16.6%) were subsequently eliminated from the final analysis. We therefore studied 1005 patients, 533 (53%) males and 472 (47%) females, mean age 59.6 +/- 20 years. On the basis of the Atlanta classification of acute pancreatitis, 753 patients of the 1005 cases analysed (75%) were mild and 252 patients (25%) severe. The aetiology was biliary in 60% of the patients, related to alcohol abuse in 8.5%, while in 21% of the cases it could not be identified. Over 80% of the patients (83%) were admitted to hospital within 24 h from the onset of clinical symptoms, while only 6% were admitted after 48 h. In particular, 65% of the patients were admitted to hospital within the first 12 h. Antibiotics were used in 85% of the severe and 75% of mild forms. Endoscopic therapy was carried out in 65% of the severe cases, but only in 40% it was carried out prior to 72 h. Eighty-five patients (8.5% of the total, 34% of the severe forms) underwent surgical intervention: 20% on the first day, 38.5% within the fourth day, and the remaining (41.5% of the cases) later on for infected necrosis. The mean duration of hospitalisation for patients with mild pancreatitis was 13 +/- 8 days, while for the severe disease it was of 30 +/- 14 days. The overall mortality rate was 5%, 17% in severe and 1.5% in mild pancreatitis. CONCLUSIONS: Acute pancreatitis in Italy is more commonly a mild disease with a biliary aetiology. The treatment of the disease is not optimal and, on the basis of these data, needs to be standardised. Despite this, the overall mortality rate is low (5%BACKGROUND AND AIM: Till now, no Italian studies providing information on acute pancreatitis have been published. The aim of this study was to evaluate the epidemiological and clinical characteristics of acute pancreatitis in Italy. MATERIALS AND METHODS: The study involved 37 Italian centres distributed homogeneously throughout the entire national territory and prospectively collected epidemiological, anamnestic, laboratory, radiological, therapeutic (pharmacological, endoscopic and surgical) data, relevant to each individual case of acute pancreatitis consecutively observed during the period from September 1996 to June 2000. RESULTS: One thousand two hundred and six case report forms were collected, but 201 patients (16.6%) were subsequently eliminated from the final analysis. We therefore studied 1005 patients, 533 (53%) males and 472 (47%) females, mean age 59.6 +/- 20 years. On the basis of the Atlanta classification of acute pancreatitis, 753 patients of the 10

    Micrometer-Thin Crystalline-Silicon Solar Cells Integrating Numerically Optimized 2-D Photonic Crystals

    Full text link
    A 2-D photonic crystal was integrated experimentally into a thin-film crystalline-silicon solar cell of 1-{\mu}m thickness, after numerical optimization maximizing light absorption in the active material. The photonic crystal boosted the short-circuit current of the cell, but it also damaged its open-circuit voltage and fill factor, which led to an overall decrease in performances. Comparisons between modeled and actual optical behaviors of the cell, and between ideal and actual morphologies, show the global robustness of the nanostructure to experimental deviations, but its particular sensitivity to the conformality of the top coatings and the spread in pattern dimensions, which should not be neglected in the optical model. As for the electrical behavior, the measured internal quantum efficiency shows the strong parasitic absorptions from the transparent conductive oxide and from the back-reflector, as well as the negative impact of the nanopattern on surface passivation. Our exemplifying case, thus, illustrates and experimentally confirms two recommendations for future integration of surface nanostructures for light trapping purposes: 1) the necessity to optimize absorption not for the total stack but for the single active material, and 2) the necessity to avoid damage to the active material by pattern etching.Comment: Authors' postprint version - Editor's pdf published online on Nov.

    Wanting to become PE teachers in Spain: connections between previous experiences and particular beliefs about school Physical Education and the development of professional teacher identities

    Get PDF
    Physical Education (PE) teachers have previous experiences that both shape their particular beliefs about the role and purpose of this school subject as well as their pedagogical practice. The present study aims to examine and deepen our knowledge of future Spanish PE teachers’ previous experiences of and beliefs about PE that condition their pedagogical practice and intentionality within this school subject. The data reported on in this paper were generated through questionnaires, life-history stories and semi-structured interviews with 24 initial teacher education students in the second year of a degree specialising in PE at a Spanish university. The data was analysed using content and narrative (thematic) analysis. The students, far from being tabula rasa, in their responses show how their previous socialisation period, their subjectivities and identities constitute particular beliefs about PE teaching. More specifically, the results reveal four key themes in the student teachers’ experiences and beliefs that represent four different factors influencing future PE teacher identities: (1) ‘Sport’; (2) ‘PE for health’; (3) ‘A focus on pedagogy’; and (4) ‘A critical orientation’. In conclusion, the study reaffirms the need for further reflection on how previous experiences and beliefs influence the development of professional teacher identities as part of initial teacher education in PE

    Measurement of the CKM angle Îł from a combination of B±→Dh± analyses

    Get PDF
    A combination of three LHCb measurements of the CKM angle Îł is presented. The decays B±→D K± and B±→Dπ± are used, where D denotes an admixture of D0 and D0 mesons, decaying into K+K−, π+π−, K±π∓, K±π∓π±π∓, K0Sπ+π−, or K0S K+K− ïŹnal states. All measurements use a dataset corresponding to 1.0 fb−1 of integrated luminosity. Combining results from B±→D K± decays alone a best-ïŹt value of Îł =72.0◩ is found, and conïŹdence intervals are set Îł ∈ [56.4,86.7]◩ at 68% CL, Îł ∈ [42.6,99.6]◩ at 95% CL. The best-ïŹt value of Îł found from a combination of results from B±→Dπ± decays alone, is Îł =18.9◩, and the conïŹdence intervals Îł ∈ [7.4,99.2]◩ âˆȘ [167.9,176.4]◩ at 68% CL are set, without constraint at 95% CL. The combination of results from B± → D K± and B± → Dπ± decays gives a best-ïŹt value of Îł =72.6◩ and the conïŹdence intervals Îł ∈ [55.4,82.3]◩ at 68% CL, Îł ∈ [40.2,92.7]◩ at 95% CL are set. All values are expressed modulo 180◩, and are obtained taking into account the effect of D0–D0 mixing

    Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma)

    Get PDF
    The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma and Bs0 -> phi gamma has been measured using 0.37 fb-1 of pp collisions at a centre of mass energy of sqrt(s) = 7 TeV, collected by the LHCb experiment. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.12 +/- 0.08 ^{+0.06}_{-0.04} ^{+0.09}_{-0.08}, where the first uncertainty is statistical, the second systematic and the third is associated to the ratio of fragmentation fractions fs/fd. Using the world average for BR(B0 -> K*0 gamma) = (4.33 +/- 0.15) x 10^{-5}, the branching fraction BR(Bs0 -> phi gamma) is measured to be (3.9 +/- 0.5) x 10^{-5}, which is the most precise measurement to date.Comment: 15 pages, 1 figure, 2 table

    First Operational Experience from the LHCb Silicon Tracker

    Get PDF
    The LHCb Silicon Tracker is a silicon micro-strip detector covering a sensitive area of 12 m2 with a total of 272k readout channels. The installation of the detector is complete and commissioning is making excellent progress. The detector has recorded first beam-induced events during LHC synchronization tests in August 2008 and in June 2009. These events have allowed the performance to be studied, and adjustments to the operational parameters to be made. In this contribution, we will draw first lessons from the in-situ commissioning of the Silicon Tracker, and present results from the reconstruction of data collected during the LHC synchronization tests

    Differential branching fraction and angular analysis of the decay B0→K∗0ÎŒ+Ό−

    Get PDF
    The angular distribution and differential branching fraction of the decay B 0→ K ∗0 ÎŒ + ÎŒ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions

    Measurements of the branching fractions of B+→ppK+ decays

    Get PDF
    The branching fractions of the decay B+ → pp̄K+ for different intermediate states are measured using data, corresponding to an integrated luminosity of 1.0 fb-1, collected by the LHCb experiment. The total branching fraction, its charmless component Mpp̄ < 2.85 GeV/c2 and the branching fractions via the resonant cc̄ states η c(1S) and ψ(2S) relative to the decay via a J/ψ intermediate state are [Equation not available: see fulltext.] Upper limits on the B + branching fractions into the η c(2S) meson and into the charmonium-like states X(3872) and X(3915) are also obtained
    • 

    corecore