254 research outputs found

    Kinetic analysis of the activation of photoactivated adenylyl cyclase (PAC), a blue-light receptor for photomovements of Euglena

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    Photoactivated adenylyl cyclase (PAC) was first purified from a photosensing organelle (the paraflagellar body) of the unicellular flagellate Euglena gracilis, and is regarded as the photoreceptor for the step-up photophobic response. Here, we report the kinetic properties of photoactivation of PAC and a change in intracellular cAMP levels upon blue light irradiation. Activation of PAC was dependent both on photon fluence rate and duration of irradiation, between which reciprocity held well in the range of 2-50 μmol m-2 s-1 (total fluence of 1200 μmol m-2). Intermittent irradiation also caused activation of PAC in a photon fluence-dependent manner irrespective of cycle periods. Wavelength dependency of PAC activation showed prominent peaks in the UV-B/C, UV-A and blue regions of the spectrum. The time course of the changes in intracellular cAMP levels corresponded well with that of the step-up photophobic response. From this and the kinetic properties of PAC photoactivation, we concluded that an increase in intracellular cAMP levels evoked by photoactivation of PAC is a key event of the step-up photophobic response

    Yeast functional screen to identify genes conferring salt stress tolerance in Salicornia europaea

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    Salinity is a critical environmental factor that adversely affects crop productivity. Halophytes have evolved various mechanisms to adapt to saline environments. Salicornia europaea L. is one of the most salt-tolerant plant species. It does not have special salt-secreting structures like a salt gland or salt bladder, and is therefore a good model for studying the common mechanisms underlying plant salt tolerance. To identify candidate genes encoding key proteins in the mediation of salt tolerance in S. europaea, we performed a functional screen of a cDNA library in yeast. The library was screened for genes that allowed the yeast to grow in the presence of 1.3 M NaCl. We obtained three full-length S. europaea genes that confer salt tolerance. The genes are predicted to encode (1) a novel protein highly homologous to thaumatin-like proteins, (2) a novel coiled-coil protein of unknown function, and (3) a novel short peptide of 32 residues. Exogenous application of a synthetic peptide corresponding to the 32 residues improved salt tolerance of Arabidopsis. The approach described in this report provides a rapid assay system for large-scale screening of S. europaea genes involved in salt stress tolerance and supports the identification of genes responsible for such mechanisms. These genes may be useful candidates for improving crop salt tolerance by genetic transformation

    A Case of Focal Choroidal Excavation Development Associated with Multiple Evanescent White Dot Syndrome

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    Focal choroidal excavation (FCE) is described as an excavated lesion of the choroid that can be detected by optical coherence tomography (OCT). While the exact pathogenesis of FCE remains unclear, it has been proposed in some cases that there is an association with the inflammation in the outer retina. We present a case of FCE development that was detected by spectral domain OCT (SD-OCT) and found to be associated with multiple evanescent white dot syndrome (MEWDS). A 40-year-old Japanese woman was diagnosed with MEWDS based on multiple white dots observed from the posterior pole to the midperiphery, along with yellow granularity in the fovea. SD-OCT revealed separation between the retinal pigment epithelium (RPE) and Bruch’s membrane (BM) and discontinuations of the ellipsoid zone, RPE, and BM. At 4 weeks after onset, several of the white dots disappeared, the yellow granularity in the fovea became small, and we detected nonconforming choroidal excavation under the central fovea. The choroidal excavation gradually deepened and changed to a conforming pattern. These findings suggest that the degree of the impairment caused by inflammation and the plasticity of the BM and RPE complex may be associated with different types of acquired FCE

    EMC and Polarized EMC Effects in Nuclei

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    We determine nuclear structure functions and quark distributions for 7^7Li, 11^{11}B, 15^{15}N and 27^{27}Al. For the nucleon bound state we solve the covariant quark-diquark equations in a confining Nambu--Jona-Lasinio model, which yields excellent results for the free nucleon structure functions. The nucleus is described using a relativistic shell model, including mean scalar and vector fields that couple to the quarks in the nucleon. The nuclear structure functions are then obtained as a convolution of the structure function of the bound nucleon with the light-cone nucleon distributions. We find that we are readily able to reproduce the EMC effect in finite nuclei and confirm earlier nuclear matter studies that found a large polarized EMC effect.Comment: 8 pages, 9 figure

    Dinâmica espacial de lagoas marginais presentes no rio Aiuruoca, MG, em períodos de cheia e seca

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    Floodplains are lands periodically covered with water when rivers overflow their banks. In the tropics, a large portion of fish communities uses the floodplains as habitats for feeding, reproduction, and refuge. For this reason, these habitats are priority for fish conservation and management. The present work aims to analyze the classification resulting from object-based method of floodplains, estimating the connectivity with Aiuruoca river. The study required 2 images of Landsat TM sensor, with 30 meters of spatial resolution all obtained in 2001. Given its efficiency to detect floodplain changes and its automated character, this method seems to constitute an operational tool adequate for floodplain monitoring. Lagoas marginais são utilizadas por comunidades de peixes como habitat, alimentação, reprodução e refúgio. Por esta razão estes ambientes são considerados prioritários à conservação e manejos. O presente estudo objetivou realizar a classificação orientada a objeto no intuito de localizar as lagoas marginais presentes no entorno do rio Aiuruoca, identificando a conexão destas ao rio em períodos de cheia e seca. Utilizou-se duas imagens Landsat 5TM, com 30 metros de resolução espacial do ano 2001, representativas do período de cheia e seca, com uma área de estudo de 3.342 km2. A classificação resultou em valores de precisão global variando de 98,9% para a época de cheia e em 98,8% para a época de seca, e de 63% e 52% de precisão pelo índice de Kappa para épocas de cheia e seca, respectivamente. Os resultados indicaram alterações no número, área e na conectividade de  lagoas marginais para os períodos de chuva e seca. Este método se mostrou bastante adequado na identificação de lagoas marginais e possui grande importância no monitoramento das alterações dos ciclos a que estes ambientes estão submetidos, possibilitando o estudo da dinâmica e a possibilidade de utilização no monitoramento e gestão destes ambientes

    First Data Release of the Hyper Suprime-Cam Subaru Strategic Program

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    The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is a three-layered imaging survey aimed at addressing some of the most outstanding questions in astronomy today, including the nature of dark matter and dark energy. The survey has been awarded 300 nights of observing time at the Subaru Telescope and it started in March 2014. This paper presents the first public data release of HSC-SSP. This release includes data taken in the first 1.7 years of observations (61.5 nights) and each of the Wide, Deep, and UltraDeep layers covers about 108, 26, and 4 square degrees down to depths of i~26.4, ~26.5, and ~27.0 mag, respectively (5sigma for point sources). All the layers are observed in five broad bands (grizy), and the Deep and UltraDeep layers are observed in narrow bands as well. We achieve an impressive image quality of 0.6 arcsec in the i-band in the Wide layer. We show that we achieve 1-2 per cent PSF photometry (rms) both internally and externally (against Pan-STARRS1), and ~10 mas and 40 mas internal and external astrometric accuracy, respectively. Both the calibrated images and catalogs are made available to the community through dedicated user interfaces and database servers. In addition to the pipeline products, we also provide value-added products such as photometric redshifts and a collection of public spectroscopic redshifts. Detailed descriptions of all the data can be found online. The data release website is https://hsc-release.mtk.nao.ac.jp/.Comment: 34 pages, 20 figures, 7 tables, moderate revision, accepted for publication in PAS

    Real-world management of treatment-naïve diabetic macular oedema : 2-year visual outcome focusing on the starting year of intervention from STREAT-DMO study

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    Background/aims To investigate the yearly change of real-world outcomes for best corrected visual acuity (BCVA) after 2-year clinical intervention for treatment-naïve diabetic macular oedema (DMO). Methods Retrospective analysis of aggregated, longitudinal medical records obtained from 27 retina specialised institutions in Japan from Survey of Treatment for DMO database. A total of 2049 treatment-naïve centre involving DMO eyes of which the initial intervention started between 2010 and 2015, and had been followed for 2 years, were eligible. As interventions, antivascular endothelial growth factor (VEGF) agents, local corticosteroids, macular photocoagulation and vitrectomy were defined. In each eye, baseline and final BCVA, the number of each intervention for 2 years was extracted. Each eye was classified by starting year of interventional treatment. Results Although baseline BCVA did not change by year, 2-year improvement of BCVA had been increased, and reached to +6.5 letters in the latest term. There is little difference among starting year about proportions of eyes which BCVA gained >15 letters, in contrast to those which lost >15 letters were decreased by year. The proportion of eyes receiving anti-VEGF therapy was dramatically increased, while those receiving the other therapies were gradually decreased. The proportion of eyes which maintained socially good vision of BCVA>20/40 has been increased and reached to 59.0% in the latest term. Conclusion For recent years, treatment patterns for DMO have been gradually but certainly changed; as a result, better visual gain, suppression of worsened eyes and better final BCVA have been obtained. Anti-VEGF therapy has become the first-line therapy and its injection frequency has been increasing

    Real-world management of treatment-naïve diabetic macular oedema in Japan : two-year visual outcomes with and without anti-VEGF therapy in the STREAT-DME study

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    Background/Aims To investigate real-world outcomes for best-corrected visual acuity (BCVA) after 2-year clinical intervention for treatment-naïve, centr-involving diabetic macular oedema (DME). Methods Retrospective analysis of longitudinal medical records obtained from 27 institutions specialising in retinal diseases in Japan. A total of 2049 eyes with treatment-naïve DME commencing intervention between 2010 and 2015 who were followed for 2 years were eligible. Interventions for DME included anti-vascular endothelial growth factor (VEGF) therapy, local corticosteroid therapy, macular photocoagulation and vitrectomy. Baseline and final BCVA (logMAR) were assessed. Eyes were classified by the treatment pattern, depending on whether anti-VEGF therapy was used, into an anti-VEGF monotherapy group (group A), a combination therapy group (group B) and a group without anti-VEGF therapy (group C). Results The mean 2-year improvement of BCVA was −0.04±0.40 and final BCVA of >20/40 was obtained in 46.3% of eyes. Based on the treatment pattern, there were 427 eyes (20.9%) in group A, 807 eyes (39.4%) in group B and 815 eyes (39.8%) in group C. Mean improvement of BCVA was −0.09±0.39, –0.02±0.40 and −0.05±0.39, and the percentage of eyes with final BCVA of >20/40 was 49.4%, 38.9%, and 52.0%, respectively. Conclusion Following 2-year real-world management of treatment-naïve DME in Japan, BCVA improved by 2 letters. Eyes treated by anti-VEGF monotherapy showed a better visual prognosis than eyes receiving combination therapy. Despite treatment for DME being selected by specialists in consideration of medical and social factors, a satisfactory visual prognosis was not obtained, but final BCVA remained >20/40 in half of all eyes

    The Hyper Suprime-Cam SSP Survey: Overview and Survey Design

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    Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of the 8.2m Subaru telescope on the summit of Maunakea in Hawaii. A team of scientists from Japan, Taiwan and Princeton University is using HSC to carry out a 300-night multi-band imaging survey of the high-latitude sky. The survey includes three layers: the Wide layer will cover 1400 deg2^2 in five broad bands (grizygrizy), with a 5σ5\,\sigma point-source depth of r26r \approx 26. The Deep layer covers a total of 26~deg2^2 in four fields, going roughly a magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter still in two pointings of HSC (a total of 3.5 deg2^2). Here we describe the instrument, the science goals of the survey, and the survey strategy and data processing. This paper serves as an introduction to a special issue of the Publications of the Astronomical Society of Japan, which includes a large number of technical and scientific papers describing results from the early phases of this survey.Comment: 14 pages, 7 figures, 5 tables. Corrected for a typo in the coordinates of HSC-Wide spring equatorial field in Table
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