56,395 research outputs found
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
HIV protease inhibitors attenuate adherence of Candida albicans to epithelial cells in vitro
No full textOropharyngeal candidiasis is one of the first and most commonly reported opportunistic infections of untreated AIDS patients. With the introduction of the new antiviral HAART therapy, including HIN protease inhibitors, this mucocutaneous infection is nowadays only rarely observed in treated patients. It was recently shown that HIV protease inhibitors have a direct attenuating effect on Candida albicans secreted aspartic proteinases (Saps), an investigation prompted by the fact that both Sap and HIV protease belong to the superfamily of aspartic proteinases and by the observation that mucocutaneous infections sometimes resolve even in the absence of an immunological improvement of the host. As these Saps are important fungal virulence factors and play a key role in adhesion to human epithelial cells we tried to assess the effect of the HIV protease inhibitors Ritonavir, Indinavir and Saquinavir on fungal adhesion to these cells. The effect on phagocytosis by polymorphonuclear leukocytes was also assessed. Ritonavir was found to be the most potent inhibitor of fungal adhesion. A dose-dependent inhibition of adhesion to epithelial cells was found already at 0.8 muM and was significant at 4 muM or higher, at 500 muM the inhibition was about 55%. Indinavir and Saquinavir inhibited significantly at 4 muM or 20 muM, respectively; at 500 muM the inhibition was 30% or 50%. In contrast, no protease inhibitor was able to modulate phagocytosis of Candida by polymorphonuclear leukocytes. In conclusion, inhibition of Saps by HIV protease inhibitors may directly help to ease the resolution of mucosal candidiasis. In future, derivatives of HIV protease inhibitors, being more specific for the fungal Saps, may form an alternative in the treatment of mucosal candidiasis insensitive to currently available antimycotics. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved
Phantomstudie zur Detektion simulierter Läsionen an fünf verschiedenen digitalen und einem konventionellen Mammographiesystem
No full textPurpose: Experimental phantom study for the detection of simulated lesions with five different digital and one conventional screen-film mammography system. Materials and Methods: Three radiographs were obtained at various configurations of the phantom with one conventional screen-film system (Mammomat 3000 N) (Siemens), five digital systems (high resolution computed radiography system [Fuji/Siemens], one a-Si detector [GE Medical Systems], two a-Se detectors [Siemens; Hologic / Lorad] and one CCD detector [Fischer Imaging]), applying the same exposure parameters. The Wisconsin Mammographic Random Phantom, Model 152 A, was used. Five investigators with different experience in mammography (3 months to more than 4 years) evaluated the 18 randomly selected radiographs. Results: No significant differences were found in the detection rate of simulated breast lesions for conventional screen-film mammography (84.9%), high resolution computed radiography (86.7%) and digital mammography with an a-Si detector (89.8%). Highly significantly better results (p<0.001) were found with the two a-Se systems (97.3%) and the CCD system (100%). Conclusion: Conventional screen-film mammography can be replaced by high resolution computed radiography and digital mammography with a-Si-, a-Se- and CCD-detectors. This has to be confirmed in further clinical studies
Perfusion of the interventricular septum during ventilation with positive end-expiratory pressure (PEEP)
No full textObjective: To determine whether regional hypoperfusion of the interventricular septum occurs during ventilation with positive end-expiratory pressure.
Design: Animal study.
Animals: Anesthetized, closed chest dogs (n = 8).
Interventions: Induction of experimental adult respiratory distress syndrome (ARDS) and then ventilation with 10,15, and 20 cm H2O of positive end-expiratory pressure.
Measurements and Main Results: Cardiac output and regional interventricular septum blood flow 'were assessed at control, at induction of experimental ARDS, and at each level of positive end-expiratory pressure. Ventilation with 20 cm H2O of positive end-expiratory pressure decreased cardiac output (-32% vs. control, p <.05), and did not change absolute, but increased relative (to cardiac output) interventricular septum blood flow. During experimental ARDS and ventilation at 20 cm H2O end-expiratory pressure, there was a redistribution of flow toward the right ventricular free wall (+93%, p < .001) and the right ventricular part of the interventricular septum (+68%, p < .01), while flow to the left ventricular interventricular septum and to the left ventricular free wall remained unchanged. Locally hypoperfused interventricular septum areas or findings indicative of interventricular septum ischemia were not observed during positive end-expiratory pressure.
Conclusions: The decrease in cardiac output during positive end-expiratory pressure is not caused by impaired interventricular septum blood supply. The preferential perfusion of the right ventricular interventricular septum indicates increased local right ventricular interventricular septum oxygen-demand and suggests that during positive end-expiratory pressure, this part of the interventricular septum functionally dissociates from the left ventricular interventricular septum and the left ventricular free wall to support the stressed right ventricle
HIV-1 and its transmembrane protein gp41 bind to different Candida species modulating adhesion
No full textExperimental investigations for dose reduction by optimizing the radiation quality for digital mammography with an a-Se detector
No full textPurpose: Reduction of radiation exposure at an adequate image quality by optimizing the radiation quality for a new system of full-field digital mammography using a digital detector (a-Se). Materials and Methods: The investigations were performed using a digital mammography system Novation (TM) (Siemens, Erlangen). The system was constructed with a bimetal anode (molybdenum and tungsten) and the possibility of changing the filter (molybdenum/rhodium). The test object was the Wisconsin Mammography Random Phantom Model 152 A (Radiation Measurements Inc.) of which images were acquired using the digital technique with the tungsten anode and rhodium filter at different tube voltages (26-35 kV) and tube loads (40-100 mAs) and compared to images in the molybdan/molybdan molybdenum/ molybdenum technique. To quantify the image quality, we used the detection rate of the simulated lesions in the phantom. Results: Increasing the tube voltage significantly decreases the average glandular dose when using AEC (Automatic Exposure Control), i.e., constant detector dose. At the same time, the image quality decreases significantly with respect to the detection rate (26 K 1 mGy, 95.1%; 35 kV, 0.7 mGy, 82.7%). As a good compromise between the necessary diagnostic image quality and the lowest dose exposition, 28 kV and 60 mAs were selected for imaging with the tungsten/rhodium anode/filter combination. A further change to the tube load did not make sense because a decrease of 10% resulted in a significant decrease in the detection rate while only a 2% increase in detection rate was achieved for a 65% increase in radiation exposure. Conclusion: The results of this phantom study demonstrate that the routine use of the tungsten anode in combination with a rhodium filter for full-field digital mammography with an a-Se detector in contrast to a molybdan/molybdan molybdenum/molybdenum anode/filter combination results in a reduction of the average glandular dose of up to 30% without loss of diagnostic image quality
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Convective–reactive nucleosynthesis of K, Sc, Cl and p-process isotopes in O–C shell mergers
No full text© 2017 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. We address the deficiency of odd-Z elements P, Cl, K and Sc in Galactic chemical evolution models through an investigation of the nucleosynthesis of interacting convective O and C shells in massive stars. 3D hydrodynamic simulations of O-shell convection with moderate C-ingestion rates show no dramatic deviation from spherical symmetry. We derive a spherically averaged diffusion coefficient for 1D nucleosynthesis simulations, which show that such convective-reactive ingestion events can be a production site for P, Cl, K and Sc. An entrainment rate of 10-3M⊙s-1features overproduction factors OPs≈ 7. Full O-C shell mergers in our 1D stellar evolution massive star models have overproduction factors OPm> 1 dex but for such cases 3D hydrodynamic simulations suggest deviations from spherical symmetry. γ - process species can be produced with overproduction factors of OPm> 1 dex, for example, for130, 132Ba. Using the uncertain prediction of the 15M⊙, Z = 0.02 massive star model (OPm≈ 15) as representative for merger or entrainment convective-reactive events involving O- and C-burning shells, and assume that such events occur in more than 50 per cent of all stars, our chemical evolution models reproduce the observed Galactic trends of the odd-Z elements
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Comparing the clinical value of spot view mammography with reduced pixel size to monitor zooming by reporting microcalcifications in digital mammography
No full textPurpose: Evaluation of the diagnostic value of breast specimen imaging with a digital mammographic system using a detector system with changeable pixel size compared to standard mode imaging in different monitor display modes. Materials and Methods: Using the digital mammographic system SenoScan (Fischer Imaging, Denver, USA), 50 diagnostic breast specimens with microcalcifications were visualized in both standard mode (pixel size 54 pm) and high resolution mode (pixel size 27 pm). The resulting radiographs were displayed 1:1 on a monitor. Standard mode images (pixel size 54 mu m) were additionally displayed in a 2:1 mode. A total of 5 readers with different mammographic experience analyzed the type of the microcalcifications on the basis of the different display modes. The images were presented randomly. The findings were subsequently compared to the histology. Results: The high resolution mode yielded slightly but not significantly better results than the standard mode on average for all 5 readers. Compared to a sensitivity of 80% and a specificity of 72% (PPV=74%, NPV=78%) in the standard mode, the high resolution mode provided a sensitivity of 86% and a specificity of 74% (PPV = 77%, NPV = 83%). The standard mode images on a 2:1 monitor display yielded 84% and 74% (PPV = 76%, NPV = 82%). Conclusion: The high resolution mode did not significantly increase the sensitivity and specificity of the microcalcification reading. A similar improvement was achieved by the 2:1 display mode, i.e. digital monitor zooming. For the clinical situation this means that there is no diagnostic advantage from using a high resolution target view with this mammographic system
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