231 research outputs found
Chemically engineered extracts of St Johnâs wort as sources of polyprenylated acylphloroglucinols to prevent endothelial dysfunction
International audienc
13C-NMR dereplication of complex mixtures: predicted vs experimental chemical shifts databases
The Spitzer Survey of the Small Magellanic Cloud: S3MC Imaging and Photometry in the Mid- and Far-Infrared Wavebands
We present the initial results from the Spitzer Survey of the Small
Magellanic Cloud (S3MC), which imaged the star-forming body of the Small
Magellanic Cloud (SMC) in all seven MIPS and IRAC wavebands. We find that the
F_8/F_24 ratio (an estimate of PAH abundance) has large spatial variations and
takes a wide range of values that are unrelated to metallicity but
anticorrelated with 24 um brightness and F_24/F_70 ratio. This suggests that
photodestruction is primarily responsible for the low abundance of PAHs
observed in star-forming low-metallicity galaxies. We use the S3MC images to
compile a photometric catalog of ~400,000 mid- and far-infrared point sources
in the SMC. The sources detected at the longest wavelengths fall into four main
categories: 1) bright 5.8 um sources with very faint optical counterparts and
very red mid-infrared colors ([5.8]-[8.0]>1.2), which we identify as YSOs. 2)
Bright mid-infrared sources with mildly red colors (0.16<[5.8]-[8.0]<0.6),
identified as carbon stars. 3) Bright mid-infrared sources with neutral colors
and bright optical counterparts, corresponding to oxygen-rich evolved stars.
And, 4) unreddened early B stars (B3 to O9) with a large 24 um excess. This
excess is reminiscent of debris disks, and is detected in only a small fraction
of these stars (<5%). The majority of the brightest infrared point sources in
the SMC fall into groups one to three. We use this photometric information to
produce a catalog of 282 bright YSOs in the SMC with a very low level of
contamination (~7%).Comment: Accepted for publication in The Astrophysical Journal. Given the
draconian figure file-size limits implemented in astro-ph, readers are
encouraged to download the manuscript with full quality images from
http://celestial.berkeley.edu/spitzer/publications/s3mcsurvey.pd
Three-micron spectra of AGB stars and supergiants in nearby galaxies
The dependence of stellar molecular bands on the metallicity is studied using
infrared L-band spectra of AGB stars (both carbon-rich and oxygen-rich) and
M-type supergiants in the Large and Small Magellanic Clouds (LMC and SMC) and
in the Sagittarius Dwarf Spheroidal Galaxy. The spectra cover SiO bands for
oxygen-rich stars, and acetylene (C2H2), CH and HCN bands for carbon-rich AGB
stars. The equivalent width of acetylene is found to be high even at low
metallicity. The high C2H2 abundance can be explained with a high
carbon-to-oxygen (C/O) ratio for lower metallicity carbon stars. In contrast,
the HCN equivalent width is low: fewer than half of the extra-galactic carbon
stars show the 3.5micron HCN band, and only a few LMC stars show high HCN
equivalent width. HCN abundances are limited by both nitrogen and carbon
elemental abundances. The amount of synthesized nitrogen depends on the initial
mass, and stars with high luminosity (i.e. high initial mass) could have a high
HCN abundance. CH bands are found in both the extra-galactic and Galactic
carbon stars. None of the oxygen-rich LMC stars show SiO bands, except one
possible detection in a low quality spectrum. The limits on the equivalent
widths of the SiO bands are below the expectation of up to 30angstrom for LMC
metallicity. Several possible explanations are discussed. The observations
imply that LMC and SMC carbon stars could reach mass-loss rates as high as
their Galactic counterparts, because there are more carbon atoms available and
more carbonaceous dust can be formed. On the other hand, the lack of SiO
suggests less dust and lower mass-loss rates in low-metallicity oxygen-rich
stars. The effect on the ISM dust enrichment is discussed.Comment: accepted for A&
Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise
The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue
Is the meiofauna a good indicator for climate change and anthropogenic impacts?
Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research
Anxiety and depression after prostate cancer diagnosis and treatment: 5-year follow-up
To document anxiety and depression from pretreatment till 5-year follow-up in 299 men with localized prostate cancer. To assess, if baseline scores were predictive for anxiety and depression at 1-year follow-up. Respondents completed four assessments (pretreatment, at 6 and 12 months, and at 5-year follow-up) on anxiety, depression and mental health. Respondents were subdivided according to therapy (prostatectomy or radiotherapy) and high vs low-anxiety. Pretreatment 28% of all patients were classified as âhigh-anxiety'; their average anxiety scores decreased significantly post-treatment, that is towards less anxiety. At all assessments, high-anxiety men treated by prostatectomy reported less depression than high-anxiety men treated by radiotherapy. Of men treated by radiotherapy, 27% reported clinical significant levels of depression while 20% is expected in a general population. The improvement in mental health at 6-months follow-up was statistically significant and clinically meaningful in all respondent groups. Sensitivity of anxiety at baseline as a screening tool was 71% for anxiety and 60% for symptoms of depression. We recommend clinicians to attempt early detection of patients at risk of high levels of anxiety and depression after prostate cancer diagnosis since prevalence is high. STAI-State can be a useful screening tool but needs further development
Hydroponic cultivation of Physalis angulata L.: growth and production under nitrogen doses1
Ultrasound-diagnosed disorders in shoulder patients in daily general practice: a retrospective observational study
Xenopus as a Model System for the Study of GOLPH2/GP73 Function: Xenopus golph2 Is Required for Pronephros Development
GOLPH2 is a highly conserved protein. It is upregulated in a number of tumors and is being considered as an emerging biomarker for related diseases. However, the function of GOLPH2 remains unknown. The Xenopus model is used to study the function of human proteins. We describe the isolation and characterization of Xenopus golph2, which dimerizes and localizes to the Golgi in a manner similar to human GOLPH2. Xenopus golph2 is expressed in the pronephros during early development. The morpholino-mediated knockdown of golph2 results in edema formation. Additionally, Nephrin expression is enhanced in the glomus, and the expression of pronephric marker genes, such as atp1b1, ClC-K, NKCC2, and NBC1, is diminished in the tubules and duct. Expression patterns of the transcription factors WT1, Pax2, Pax8, Lim1, GATA3, and HNF1ÎČ are also examined in the golph2 knockdown embryos, the expression of WT1 is increased in the glomus and expanded laterally in the pronephric region. We conclude that the deletion of golph2 causes an increase in the expression of WT1, which may promote glomus formation and inhibit pronephric tubule differentiation
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