1,724 research outputs found

    Extra-large crystal emulsion detectors for future large-scale experiments

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    Photographic emulsion is a particle tracking device which features the best spatial resolution among particle detectors. For certain applications, for example muon radiography, large-scale detectors are required. Therefore, a huge surface has to be analyzed by means of automated optical microscopes. An improvement of the readout speed is then a crucial point to make these applications possible and the availability of a new type of photographic emulsions featuring crystals of larger size is a way to pursue this program. This would allow a lower magnification for the microscopes, a consequent larger field of view resulting in a faster data analysis. In this framework, we developed new kinds of emulsion detectors with a crystal size of 600-1000 nm, namely 3-5 times larger than conventional ones, allowing a 25 times faster data readout. The new photographic emulsions have shown a sufficient sensitivity and a good signal to noise ratio. The proposed development opens the way to future large-scale applications of the technology, e.g. 3D imaging of glacier bedrocks or future neutrino experiments.Comment: Version accepted for publication in JINS

    Aggregation number distributions and mesoglobules in dilute solutions of diblock and triblock copolymers

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    We investigate the aggregation number and size distributions for inter-molecular clusters of amphiphilic diblock and triblock copolymers in poor solvent at very low concentrations. Diblocks and triblocks with hydrophilic ends are shown to possess narrow distributions corresponding to formation of monodispersed mesoglobules. Diblocks with hydrophobic ends are found to produce inter-cluster multimers due to bridging by the hydrophilic middle blocks, resulting in polydisperse distributions. Implications of these observations for preparation of monodispersed nanoparticles and, potentially, understanding of the quaternary structure of proteins are discussed.Comment: 4 pages, 4 PS figures. Accepted for publication in EP

    Association analysis of tissue inhibitor of metalloproteinase2 gene polymorphisms with COPD in Egyptians

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    AbstractProteinase/antiproteinase imbalance is recognized to play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). A relative increase in the activities of matrix metalloproteinases might be caused by mutations of tissue inhibitor of metalloproteinase2 (TIMP2). Recently, two polymorphisms of the TIMP2 gene, +853 G/A and −418 G/C (+551 and −720 from the translation initiation site), have been shown to be associated with the development of COPD in the Japanese population. In this study, a case-control association analysis for these polymorphisms was conducted in the Egyptian population using 106 COPD patients and 72 healthy controls. The genotype frequency of +853 G/A was significantly different between the patient and the control groups (P=0.029), although no significant difference was detected in the allele frequency between the two groups. These results suggest that the +853 G/A polymorphism of the TIMP2 gene might be associated with COPD across ethnicities. In contrast, neither the distributions of genotype nor allele frequencies of –418 G/C were significantly different between the two groups, raising the possibility that a combination of different genetic factors contributes to the development of COPD in different ethnic groups

    Cytokine and chemokine response in children with the 2009 pandemic influenza A (H1N1) virus infection

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    We report the systemic cytokine and chemokine response in children with the 2009 pandemic influenza A (H1N1) virus infection. In patients with pneumonia, the serum levels of IFN-γ and IL-5 were significantly higher than those in patients without pneumonia. This tendency was also present for IL-6, IL-8, IL-10, IL-13, and MCP-1 in patients with pneumonia. Among patients with pneumonia, the levels of MCP-1 were significantly higher in the group of patients with pneumonia with severe respiratory failure than patients with mild pneumonia

    A reversible lesion of the corpus callosum splenium with adult influenza-associated encephalitis/encephalopathy: a case report

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    <p>ABstract</p> <p>Introduction</p> <p>Influenza virus-associated encephalitis/encephalopathy is a severe childhood illness with a poor prognosis. Adult case reports are rare and, to date, there have been no reports of adults with a mild subcortical encephalopathy with reversible lesions of the corpus callosum splenium.</p> <p>Case presentation</p> <p>A previously healthy 35-year-old man presented with acute progressive tetraplegia, transcortical motor aphasia and a mild decrease in his consciousness during his recovery after receiving oseltamivir phosphate treatment, and influenza type A antiviral medication. The initial magnetic resonance imaging study at day 1 showed symmetrical diffuse lesions in the white matter and a lesion on the central portion of the corpus callosum splenium. These findings had resolved on follow-up studies at day 8 and day 146. His neurological deficits mostly recovered within 12 hours following methylprednisolone pulse therapy. The levels of interleukin-6 and interleukin-10 in his blood and cerebrospinal fluid were initially elevated, but rapidly decreased to normal levels by day 8.</p> <p>Conclusion</p> <p>It is important for clinicians to recognize that even in adulthood, the subcortical encephalopathy observed during the therapeutic treatment for influenza type A infection can occur in conjunction with a reversible lesion of the corpus callosum, which may recover quickly. In addition, the cytokine storm in the blood system and the corticospinal cavity may play an important role in the etiology of the disease process.</p

    Stability of Terrestrial Planets in the Habitable Zone of Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208

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    We have undertaken a thorough dynamical investigation of five extrasolar planetary systems using extensive numerical experiments. The systems Gl 777 A, HD 72659, Gl 614, 47 Uma and HD 4208 were examined concerning the question of whether they could host terrestrial like planets in their habitable zones (=HZ). First we investigated the mean motion resonances between fictitious terrestrial planets and the existing gas giants in these five extrasolar systems. Then a fine grid of initial conditions for a potential terrestrial planet within the HZ was chosen for each system, from which the stability of orbits was then assessed by direct integrations over a time interval of 1 million years. The computations were carried out using a Lie-series integration method with an adaptive step size control. This integration method achieves machine precision accuracy in a highly efficient and robust way, requiring no special adjustments when the orbits have large eccentricities. The stability of orbits was examined with a determination of the Renyi entropy, estimated from recurrence plots, and with a more straight forward method based on the maximum eccentricity achieved by the planet over the 1 million year integration. Additionally, the eccentricity is an indication of the habitability of a terrestrial planet in the HZ; any value of e>0.2 produces a significant temperature difference on a planet's surface between apoapse and periapse. The results for possible stable orbits for terrestrial planets in habitable zones for the five systems are summarized as follows: for Gl 777 A nearly the entire HZ is stable, for 47 Uma, HD 72659 and HD 4208 terrestrial planets can survive for a sufficiently long time, while for Gl 614 our results exclude terrestrial planets moving in stable orbits within the HZ.Comment: 14 pages, 18 figures submitted to A&
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