192 research outputs found

    What One Can Learn From the Cloud Condensation Nuclei (CCN) Size Distributions as Monitored by the BEO Moussala?

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    In this proceeding we report initial studies into the big data set acquired by the Cloud Condensation Nuclei (CCN) counter of the Basic Environmental Observatory (BEO) Moussala over the whole 2016 year at a frequency of 1 Hz. First, we attempt to reveal correlations between the results for CCN number concentrations on the timescale of a whole year (2016) as averaged over 12 month periods with the meteorological parameters for the same period and with the same time step. Then, we zoom into these data and repeat the study on the timescale of a month for two months from 2016, January and July, with a day time step. For the same two months we show the CCN size distributions averaged over day periods. Finally, we arrive at our main result: typical, in terms of maximal and minimal number concentrations, CCN size distributions for chosen hours, one hour for each month of the year, hence 24 distributions in total. These data show a steady pattern of peaks and valleys independent of the concrete number concentration which moves up and down the number concentrations (y-axis) without significant shifts along the sizes (x-axis).Comment: 6 pages, 4 figure, The 10th Jubilee Conference of the Balkan Physical Union (BPU10), 26-30 August, Sofia, Bulgari

    First results from the CERN Axion Solar Telescope (CAST)

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    Hypothetical axion-like particles with a two-photon interaction would be produced in the Sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope'') they would be transformed into X-rays with energies of a few keV. Using a decommissioned LHC test magnet, CAST has been running for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling < 1.16 10^{-10} GeV^-1 at 95% CL for m_a <~0.02 eV. This limit is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment in this axion mass range.Comment: 4 pages, accepted by PRL. Final version after the referees comment

    The search for solar axions in the CAST experiment

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    The CAST (CERN Axion Solar Telescope) experiment at CERN searches for solar axions with energies in the keV range. It is possible that axions are produced in the core of the sun by the interaction of thermal photons with virtual photons of strong electromagnetic fields. In this experiment, the solar axions can be reconverted to photons in the transversal field of a 9 Tesla superconducting magnet. At both ends of the 10m-long dipole magnet three different X-ray detectors were installed, which are sensitive in the interesting photon energy range. Preliminary results from the analysis of the 2004 data are presented: gaγ<0.9×1010_{a\gamma}<0.9\times10^{-10} GeV1^{-1} at 95% C.L. for axion masses ma<_{a} < 0.02 eV. At the end of 2005, data started to be taken with a buffer gas in the magnet pipes in order to extend the sensitivity to axion masses up to 0.8 eV.The CAST (CERN Axion Solar Telescope) experiment at CERN searches for solar axions with energies in the keV range. It is possible that axions are produced in the core of the sun by the interaction of thermal photons with virtual photons of strong electromagnetic fields. In this experiment, the solar axions can be reconverted to photons in the transversal field of a 9 Tesla superconducting magnet. At both ends of the 10m-long dipole magnet three different X-ray detectors were installed, which are sensitive in the interesting photon energy range. Preliminary results from the analysis of the 2004 data are presented: gaγ<0.9×1010_{a\gamma}<0.9\times10^{-10} GeV1^{-1} at 95% C.L. for axion masses ma<_{a} < 0.02 eV. At the end of 2005, data started to be taken with a buffer gas in the magnet pipes in order to extend the sensitivity to axion masses up to 0.8 eV

    Magnetic Resonance Imaging-guided Active Surveillance Without Annual Rebiopsy in Patients with Grade Group 1 or 2 Prostate Cancer: The Prospective PROMM-AS Study

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    Background: Multiparametric magnetic resonance imaging (mpMRI) may allow patients with prostate cancer (PC) on active surveillance (AS) to avoid repeat prostate biopsies during monitoring. Objective: To assess the ability of mpMRI to reduce guideline-mandated biopsy and to predict grade group upgrading in patients with International Society of Urological Pathology grade group (GG) 1 or GG 2 PC using Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) scores. The hypothesis was that the AS disqualification rate (ASDQ) rate could be reduced to 15%. Design, setting and participants: PROMM-AS was a prospective study assessing 2-yr outcomes for an mpMRI-guided AS protocol. A 12 mo after AS inclusion on the basis of MRI/transrectal ultrasound fusion-guided biopsy (FBx), all patients underwent mpMRI. For patients with stable mpMRI (PRECISE 1–3), repeat biopsy was deferred and follow-up mpMRI was scheduled for 12 mo later. Patients with mpMRI progression (PRECISE 4–5) underwent FBx. At the end of the study, follow-up FBx was indicated for all patients. Outcome measurements and statistical analysis: We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for upgrading to GG 2 in the GG 1 group, and to GG 3 in the GG 2 group on MRI. We performed regression analyses that included clinical variables. Results and limitations: The study included 101 patients with PC (60 GG 1 and 41 GG 2). Histopathological progression occurred in 31 patients, 18 in the GG 1 group and 13 in the GG 2 group. Thus, the aim of reducing the ASDQ rate to 15% was not achieved. The sensitivity, specificity, PPV, and NPV for PRECISE scoring of MRI were 94%, 64%, 81%, and 88% in the GG 1 group, and 92%, 50%, 92%, and 50%, respectively, in the GG 2 group. On regression analysis, initial prostate-specific antigen (p < 0.001) and higher PRECISE score (4–5; p = 0.005) were significant predictors of histological progression of GG 1 PC. Higher PRECISE score (p = 0.009), initial Prostate Imaging-Reporting and Data System score (p = 0.009), previous negative biopsy (p = 0.02), and percentage Gleason pattern 4 (p = 0.04) were significant predictors of histological progression of GG 2 PC. Limitations include extensive MRI reading experience, the small sample size, and limited follow-up. Conclusions: MRI-guided monitoring of patients on AS using PRECISE scores avoided unnecessary follow-up biopsies in 88% of patients with GG 1 PC and predicted upgrading during 2-yr follow-up in both GG 1 and GG 2 PC. Patient summary: We investigated whether MRI (magnetic resonance imaging) scores can be used to guide whether patients with lower-risk prostate cancer who are on active surveillance (AS) need to undergo repeat biopsies. Follow-up biopsy was deferred for 1 year for patients with a stable score and performed for patients whose score progressed. After 24 months on AS, all men underwent MRI and biopsy. Among patients with grade group 1 cancer and a stable MRI score, 88% avoided biopsy. For patients with MRI score progression, AS termination was correctly recommended in 81% of grade group 1 and 92% of grade group 2 cases

    Nanoparticles can wrap epithelial cell membranes and relocate them across the epithelial cell layer

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    Although the link between the inhalation of nanoparticles and cardiovascular disease is well established, the causal pathway between nanoparticle exposure and increased activity of blood coagulation factors remains unexplained. To initiate coagulation tissue factor bearing epithelial cell membranes should be exposed to blood, on the other side of the less than a micrometre thin air-blood barrier. For the inhaled nanoparticles to promote coagulation, they need to bind lung epithelial-cell membrane parts and relocate them into the blood. To assess this hypothesis, we use advanced microscopy and spectroscopy techniques to show that the nanoparticles wrap themselves with epithelial-cell membranes, leading to the membrane's disruption. The membrane-wrapped nanoparticles are then observed to freely diffuse across the damaged epithelial cell layer relocating epithelial cell membrane parts over the epithelial layer. Proteomic analysis of the protein content in the nanoparticles wraps/corona finally reveals the presence of the coagulation-initiating factors, supporting the proposed causal link between the inhalation of nanoparticles and cardiovascular disease

    Equivocal pi-rads three lesions on prostate magnetic resonance imaging: Risk stratification strategies to avoid mri-targeted biopsies

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    We aimed to investigate the relation between largest lesion diameter, prostate-specific antigen density (PSA-D), age, and the detection of clinically significant prostate cancer (csPCa) using first-time targeted biopsy (TBx) in men with Prostate Imaging—Reporting and Data System (PI-RADS) 3 index lesions. A total of 292 men (2013–2019) from two referral centers were included. A multivariable logistic regression analysis was performed. The discrimination and clinical utility of the built model was assessed by the area under the receiver operation curve (AUC) and decision curve analysis, respectively. A higher PSA-D and higher age were significantly related to a higher risk of detecting csPCa, while the largest index lesion diameter was not. The discrimination of the model was 0.80 (95% CI 0.73–0.87). When compared to a biopsy-all strategy, decision curve analysis showed a higher net benefit at threshold probabilities of ≥2%. Accepting a missing ≤5% of csPCa diagnoses, a risk-based approach would result in 34% of TBx sessions and 23% of low-risk PCa diagnoses being avoided. In men with PI-RADS 3 index lesions scheduled for first-time TBx, the balance between the number of TBx sessions, the detection of low-risk PCa, and the detection of csPCa does not warrant a biopsy-all strategy. To minimize the risk of missing the diagnosis of csPCa but acknowledging the need of avoiding unnecessary TBx sessions and overdiagnosis, a risk-based approach is advisable

    Search for solar axions: CAST

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    The CERN Axion Solar Telescope (CAST) is searching for axions produced in the Sun's core by the Primakoff process. CAST is using a decommissioned Large Hadron Collider (LHC) test magnet where axions could be converted back into X-rays with energies up to 10 keV. Analysis of the 2003 data showed no signal above background implying an upper limit for the axion-photon coupling constant gagg < 1.16 X 10 ^-10 GeV exp -1 at 95% C.L. for ma . 0.02 eV [1]. The higher quality 2004 data is presently under analysis. CAST Phase II is scheduled to start in late 2005. This will be the first step in extending CAST's sensitivity to axion rest masses up to ~ 1 eV

    Linking Human Diseases to Animal Models Using Ontology-Based Phenotype Annotation

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    A novel method for quantifying the similarity between phenotypes by the use of ontologies can be used to search for candidate genes, pathway members, and human disease models on the basis of phenotypes alone

    A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam

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    We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very stable, compact and cost-effective X-ray FEL facility driven by a low-energy and ultra-low-emittance electron beam travelling through short-period undulators. It delivers stable hard X-ray FEL radiation at 1-Å wavelength with pulse energies of more than 500 μJ, pulse durations of ~30 fs (root mean square) and spectral bandwidth below the per-mil level. Using special configurations, we have produced pulses shorter than 1 fs and, in a different set-up, broadband radiation with an unprecedented bandwidth of ~2%. The extremely small emittance demonstrated at SwissFEL paves the way for even more compact and affordable hard X-ray FELs, potentially boosting the number of facilities worldwide and thereby expanding the population of the scientific community that has access to X-ray FEL radiation
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