1,050 research outputs found
Information Outlook, July 1999
Volume 3, Issue 7https://scholarworks.sjsu.edu/sla_io_1999/1006/thumbnail.jp
MUSE observations of M87: radial gradients for the stellar initial-mass function and the abundance of Sodium
Based on MUSE integral-field data we present evidence for a radial variation
at the low-mass end of the stellar initial-mass function (IMF) in the central
regions of the giant early-type galaxy NGC4486 (M87). We used state-of-the-art
stellar population models and the observed strength of various IMF-sensitive
absorption-line features to solve for the best low-mass tapered "bimodal" form
of the IMF, while accounting also for radial variations in stellar metallicity,
the overall -elements abundance, and the abundance of individual
elements such as Ti, O, Na and Ca. Our analysis reveals a strong IMF gradient
in M87, corresponding to an exceeding fraction of low-mass stars compared to
the case of the Milky Way toward the center of M87 that drops to nearly
Milky-way levels by 0.4 . This IMF gradient is found to correlate well
with both the radial profile for stellar metallicity and for -elements
abundance but not with stellar velocity dispersion. Such IMF variations
correspond to over a factor two increase in stellar mass-to-light M/L ratio
compared to the case of a Milky-way like IMF, consistent with other
investigations into IMF gradients in early-type galaxies, including recent
dynamical constraints on M/L radial variations in M87 by Oldham & Auger. In
addition to constraining the IMF in M87 we also looked into the abundance of
Sodium, which turned up to be super-Solar over the entire radial range of our
MUSE observations and to exhibit a considerable negative gradient. These
findings suggest an additional role of metallicity in boosting the Na-yields in
the central, metal-rich regions of M87 during its early and brief
star-formation history. Our work adds the case of M87 to the few objects that
as of today have radial constraints on their IMF or [Na/Fe] abundance, while
also illustrating the accuracy that MUSE could bring to this kind of
investigations.Comment: 17 pages, 13 figures, re-submitted for publication on MNRAS following
the referee's comment
Liquid chromatographic strategies for separation of bioactive compounds in food matrices
Nowadays, there is an increasing attention for nutraceuticals and, in general, bioactive compounds naturally present in food. Indeed, the possibility of preserving human health and preventing disease (e.g., cardiovascular diseases, cancer etc.) by the intake of healthy food is attractive for both consumers and food industries. In turn, research in this field was also prompted significantly, with the aim of characterizing these bioactive compounds and ascribe to them a specific activity. The bioactive compounds can belong to several chemical classes. However, their chemical diversity and presence in complex matrices, such as food, make it challenging both their isolation and characterization. To tackle this issue, efficient separation systems are needed, which are mainly based on chromatography. In this context, this mini-review aims to provide the reader with an overview of the most relevant and recent approaches for the separation of the most common bioactive compounds in food, in particular polyphenols, phenols, carotenoids, and peptides, by liquid chromatography approaches. © 2018 by the authors
State College Times, June 2, 1932
Volume 20, Issue 73https://scholarworks.sjsu.edu/spartan_daily_1932/1055/thumbnail.jp
What really matters? Systemic Design, motivations and values of the Circular Economy companies in Italy.
Since 2014, the Circular Economy (CE) concept is gaining an important role in the European context thanks to the specific direction given by the EU policy. This research wants to frame Italian companies who are working on CE context to understand mainly which is their approach and awareness to CE and if the design is playing a role in this transition. At the beginning of 2019, an online questionnaire was sent to the actors present in the app database ‘Mercato Circolare’ who, since March 2017, is mapping the Italian situation collecting the actors related to the CE selecting companies, events and experiences of circular citizenship. Despite the response rate was 14%, the results are interesting: 100% are SMEs; 21% are not aware to work on CE; >52% identified difficulties with value appreciation; design competencies are present in the 66% of realities and in 29% the designers by formation are founders
A rapid magnetic solid phase extraction method followed by liquid chromatography-tandem mass spectrometry analysis for the determination of mycotoxins in cereals
Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE), a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high-performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were > 60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes
Domino reaction for the controlled functionalization of sp2 carbon allotropes
Graphene and graphene related materials are a hot research topic in the material
science and are becoming a reality of increasing importance in many application
fields. Indeed, graphene has high charge-carrier mobilities, in-plane thermal
conductivity and very high elastic modulus. It is increasingly acknowledged that
application of carbon nanomaterials such as graphene has to be assisted by
functionalization, which allows to tune electronic and solubility properties, phaseforming
and self-assembly behaviour.
In this work, functionalization of graphene layers was performed with 2-(2,5-
dimethyl-1H-pyrrol-1-yl)-1,3-propanediol (serinol pyrrole, SP) [3].
SP is a serinol derivative obtained from the neat reaction of 2-amino-1,3-
propandiol with 2,5-hexanedione, with atom economy of about 85%, almost
quantitative yield and thus high atom efficiency, the only byproduct being water,
in the absence of solvent and catalyst [1, 2, 3]. Functionalization was obtained by
simply mixing nanosized high surface area graphite with SP, giving either
mechanical or thermal energy. Very high functionalization yield was found, larger
than 90% and even almost quantitative. Few layers graphene were isolated from
stable water suspensions. Reaction of SP was applied to other sp2 carbon
allotropes, such as carbon nanotubes and carbon black. Many different applications
were developed: from conductive inks to carbon papers and aerogels.
The reaction occurring between SP and graphene layers was investigated. Adducts
of a high surface area nanosized graphite were prepared with a model molecule,
1,2,5-trimethyl-1H-pyrrole (TMP). Pristine TMP, HSAG, products formed by the
reaction and HSAG-TMP adducts were studied by means of Fourier transformed
infrared spectroscopy (FT-IR), 1H-NMR and thermogravimetric analysis. DFT
modelling was carried out to predict IR spectra of HSAG-TMP reaction products and
adducts. Reaction pathway is presented. Domino reaction appears to occur:
carbocatalyzed oxidation of the pyrrole compound lead to the formation of
activated double bond, able to give rise cycloaddition with the graphitic substrate.
Such a facile and sustainable functionalization method allows the controlled
introduction of functional groups on graphitic substrate without appreciably
altering their structure
Borderline Personality in Patients with Poly-Diagnoses Treated for a Bipolar Disorder
Some patients with dysphoria, explosive behaviour, or suicidal ideation, may receive a diagnosis of, and treatment for Bipolar Disorder (BD) and, not infrequently. The coexistence of these two diagnoses has been explained in different ways. Some authors include the BPD in the bipolar spectrum; others are sceptical about the existence of real comorbidity, suggesting a misdiagnosis. This study aimed to assess the personality of this group of poly-diagnosed patients (PolyD) and hypothesised they had a pathological borderline organisation. Via the administration of the Schedler Westen Assessment Procedure (SWAP-200), we compared PolyD patients with those suffering from BPD or BD only. We performed two different MANCOVAs to test PolyD, BPD and BD patients’ differences in PD-factors, Q-traits and age. The sample comprised 45 patients (Mean age=43.3, SD=15.7; Females 57.7%, N=26). BD patients (N=15) did not present any personality disorder, they had a higher functioning and Obsessive Q-traits, and a lower Histrionic PD-factor than both PolyD (N=20) and BPD (N=10) patients. Compared to PolyD patients, BD had inferior PD-Borderline, PD-Antisocial factor and Dependent-Masochistic Q-traits, but there were no other differences with BPD patients. PolyD did not differ from BPD patients in any of the PD-factors and Q-traits. Our results suggest that PolyD patients are different from BD patients and propose to consider the pathological borderline personality as a central core of their disease
Multi-label transcriptional classification of colorectal cancer reflects tumor cell population heterogeneity
Background: Transcriptional classification has been used to stratify colorectal cancer (CRC) into molecular subtypes with distinct biological and clinical features. However, it is not clear whether such subtypes represent discrete, mutually exclusive entities or molecular/phenotypic states with potential overlap. Therefore, we focused on the CRC Intrinsic Subtype (CRIS) classifier and evaluated whether assigning multiple CRIS subtypes to the same sample provides additional clinically and biologically relevant information.
Methods: A multi-label version of the CRIS classifier (multiCRIS) was applied to newly generated RNA-seq profiles from 606 CRC patient-derived xenografts (PDXs), together with human CRC bulk and single-cell RNA-seq datasets. Biological and clinical associations of single- and multi-label CRIS were compared. Finally, a machine learning-based multi-label CRIS predictor (ML2CRIS) was developed for single-sample classification.
Results: Surprisingly, about half of the CRC cases could be significantly assigned to more than one CRIS subtype. Single-cell RNA-seq analysis revealed that multiple CRIS membership can be a consequence of the concomitant presence of cells of different CRIS class or, less frequently, of cells with hybrid phenotype. Multi-label assignments were found to improve prediction of CRC prognosis and response to treatment. Finally, the ML2CRIS classifier was validated for retaining the same biological and clinical associations also in the context of single-sample classification.
Conclusions: These results show that CRIS subtypes retain their biological and clinical features even when concomitantly assigned to the same CRC sample. This approach could be potentially extended to other cancer types and classification systems
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