1,111 research outputs found

    High sensitive X-ray films to detect electron showers in 100 GeV region

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    Nonscreen type X-ray films were used in emulsion chamber experiments to detect high energy showers in cosmic rays. Ranges of the detection threshold is from about 1 to 2 TeV depending on the exposure conditions. Different types of X-ray films and sheets i.e. high sensitive screen type X-ray films and luminescence sheets were tested. The threshold of the shower detection is found to be about 200 GeV, which is much lower than that of nonscreen type X-ray films. These films are useful to detect showers in the medium energy range, a few hundred GeV, of the cosmic ray electrons

    High energy electrons beyond 100 GEV observed by emulsion chamber

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    Much efforts have been expended to observe the spectrum of electrons in the high energy region with large area emulsion chambers exposed at balloon altitudes, and now 15 electrons beyond 1 TeV have been observed. The observed integral flux at 1 TeV is (3.24 + or - 0.87)x10(-5)/sq m sec sr. The statistics of the data around a few hundred GeV are also improving by using new shower detecting films of high sensitivity. The astrophysical significance of the observed spectrum are discussed for the propagation of electrons based on the leaky box and the nested leaky box model

    Dopamine-induced cyclic AMP increase in canine myocardium, kidney and superior mesenteric artery.

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    The effect of dopamine on cyclic AMP levels in tissue slices of canine myocardium and kidney, and in chopped superior mesenteric arterial wall was investigated to identify dopamine receptors. Tissues were incubated in modified Krebs-Henseleit Ringer bicarbonate solution at 37 degrees C for 20 min with test drugs, after 20-min preincubation. In the presence of 3-isobutyl-1-methylxanthine (IBMX), dopamine and apomorphine caused dose-dependent increases in cyclic AMP levels in the myocardium, kidney and superior mesenteric artery. Phentolamine significantly intensified the cyclic AMP-increasing effect of dopamine in the superior mesenteric artery, but it did not influence the cyclic AMP increase caused by dopamine or apomorphine in the myocardium and kidney. Propranolol markedly blocked the effect of dopamine on cyclic AMP levels in all tissues studied. Haloperidol slightly inhibited the effect of dopamine and completely blocked the effect of apomorphine in the myocardium and kidney. These data suggest that dopamine increases cyclic AMP levels by activating predominantly beta-adrenergic receptors and partly dopamine receptors in the canine myocardium, kidney and superior mesenteric artery. The present results also suggest that dopamine acts not only on beta-adrenergic and dopamine receptors but also on alpha-adrenergic receptors in the superior mesenteric artery. Contrary to the activation of beta-adrenergic and dopamine receptors, the activation of alpha-adrenergic receptors resulted in a decrease in cyclic AMP levels in this tissue.</p

    Identification of phenolic constituents of cytisus multiflorus

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    The phenolic composition of the ethanolic extract obtained from the flowers of the medicinal plant Cytisus multiflorus has been elucidated by high performance liquid chromatography, electrospray mass spectrometry and nuclear magnetic resonance analysis. The extract was mainly composed of flavones, including the common chrysin, orientin, luteolin-5-O-glucoside, luteolin-7-O-glucoside, apigenin and apigenin-7-O-glucoside, which appeared as minor components. The major flavone in the extract was chrysin-7-O-B-D-glucopyranoside, and it also contained moderate amounts of a dihydroxyflavone isomer of chrysin, as well as of 2''-O-pentosyl-6-C-hexosyl-luteolin, 2''-O-pentosyl-8-C-hexosyl-luteolin and 6''- O-(3-hydroxy-3-methylglutaroyl)-2''-O-pentosyl-C-hexosyl-apigenin, which are not commonly found in the Fabaceae family. Other novel phenolic compounds found in the ethanolic extract of C. multiflorus comprised the flavones 2''-O-pentosyl-6-C-hexosyl-apigenin, 2''-O-pentosyl-8-C-hexosyl-apigenin and 6''-O-(3-hydroxy-3-methylglutaroyl)-200-O-pentosyl-C-hexosyl-luteolin. The assessment of the biological activities of the main compounds of this extract are now keen, in order to determine their relevance in the beneficial properties of the plant

    Retinal ischemic diseases and promising therapeutic molecular targets

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    Retinal ischemia is a fundamental pathologic condition associated with retinal vascular occlusion, glaucoma, diabetic retinopathy, age-related macular degeneration, and other eye diseases. Extensive inflammation, redox imbalance, apoptosis, and abnormal vascular formation in retinal ischemia could lead to visual impairments. Developing or finding effective treatments is urgently needed to protect the eye against retinal ischemia and related damage. To address the demand, we have searched for promising therapeutic molecular targets in the eye (e.g., hypoxia-inducible factor [HIF], peroxisome proliferator-activated receptor-alpha [PPARα], and nicotinamide adenine dinucleotide [NAD+]), and found that modulations of each molecular target might protect the eye against retinal ischemic damage in terms of complex pathologic mechanisms. In the current article, we review and update the therapeutic evidence of modulation of HIF, PPARα, or NAD+ and discuss future directions for developing promising drugs based on these molecular targets. This summary urges research to obtain more solid evidence of each molecular target in retinal ischemic diseases

    Correlation between contrast sensitivity and higher-order aberration based on pupil diameter after cataract surgery

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    Takefumi Yamaguchi1,2, Kazuno Negishi1, Kazuhiko Ohnuma3, Kazuo Tsubota11Department of Ophthalmology, Keio University School of Medicine, Tokyo; 2Department of Ophthalmology, Ichikawa General Hospital, Tokyo Dental College, Chiba; 3Department of Medical System Engineering, Faculty of Engineering, Chiba University, Chiba, JapanBackground: The purpose of this study was to evaluate the correlation between contrast sensitivity and calculated higher-order aberrations based on individual natural pupil diameter after cataract surgery.Methods: This prospective study included 120 eyes from 92 patients who were randomized to receive one of four lenses, including three aspheric lenses (Acrysof SN60WF, Tecnis ZA9000, and Hoya Py60AD) and one spherical lens (Acrysof SN60AT). Contrast sensitivity, higher-order aberrations of the whole eye, and pupil diameter under photopic and mesopic conditions were measured 1 month postoperatively. Higher-order aberrations were decomposed into Zernike coefficients, calculated according to individual pupil diameter. The correlation between higher-order aberrations and contrast sensitivity was evaluated.Results: There were no significant differences in contrast sensitivity function between the four types of lenses under photopic conditions. However, the contrast sensitivity function and area under log contrast sensitivity function in the aspheric lenses were significantly better than in the spherical lens under mesopic conditions. Under mesopic conditions, spherical aberration in eyes with aspheric lenses was significantly lower than in eyes with spherical lenses (P &amp;lt; 0.05). Under photopic conditions, coma aberration had a significant negative correlation with contrast sensitivity at 12 cycles/degree. Under mesopic conditions, spherical aberration had a significant negative correlation with contrast sensitivity at 3, 6, and 12 cycles/degree with glare, and with contrast sensitivity at 6 and 18 cycles/degree without glare.Conclusion: In terms of influence on visual function, coma aberration may be more significant under photopic conditions and spherical aberration under mesopic conditions.Keywords: mesopic conditions, spherical aberration, wavefront, photopic and mesopic condition

    Editorial: Recent advances in refractive surgery

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    Ocular infestation by a juvenile leech, Myxobdella sinanensis in Japan

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    [Purpose] The case of ocular infestation by a leech is rare. We reported that Myxobdella sinanensis infests conjunctiva. [Observations] A 5-year-old girl presented with blood clots in the inner corner of the left eye, and a history bloody eye discharge and bloody tears for 5 days. She was prescribed 0.5% levofloxacin ophthalmic drops for conjunctival damage. However, her parent watched a worm moving in her conjunctiva while taking a bath. She presented again the same day, and a worm was found in the left eye of the lower conjunctival fornix and was adsorbed to the inner corner. We removed a worm under eye drop anesthesia, the next day the patient had no symptoms. We captured the worm, and it was identified morphologically and genetically as Myxobdella sinanensis. This was the first case reported of Myxobdella sinanensis be infestation in a human. [Conclusions and Importance] The ecological trait of Myxobdella sinanensis still did not remain clear, so this case report was helpful to find out a life cycle of Myxobdella sinanensis. As the outdoor population continues to increase, the cases of human parasites such as leech are expected to increase. When a patient with bloody eye discharge and bloody tears presents, we should carefully examine the conjunctiva and ocular surfaces, and interview recent history of exposure to stream water

    Observation of weak neutral current neutrino production of J/ψJ/\psi

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    Observation of \jpsi production by neutrinos in the calorimeter of the CHORUS detector exposed to the CERN SPS wide-band \numu beam is reported. A spectrum-averaged cross-section σJ/ψ\sigma^{\mathrm{J/\psi}} = (6.3 ±\pm 3.0) ×1041 cm2\times \mathrm{10^{-41}~cm^{2}} is obtained for 20 GeV Eν\leq E_{\nu} \leq 200 GeV. The data are compared with the theoretical model based on the QCD Z-gluon fusion mechanism
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