485 research outputs found
Glycolaldehyde in Perseus young solar analogs
Aims: In this paper we focus on the occurrence of glycolaldehyde (HCOCH2OH)
in young solar analogs by performing the first homogeneous and unbiased study
of this molecule in the Class 0 protostars of the nearby Perseus star forming
region. Methods: We obtained sub-arcsec angular resolution maps at 1.3mm and
1.4mm of glycolaldehyde emission lines using the IRAM Plateau de Bure (PdB)
interferometer in the framework of the CALYPSO IRAM large program. Results:
Glycolaldehyde has been detected towards 3 Class 0 and 1 Class I protostars out
of the 13 continuum sources targeted in Perseus: NGC1333-IRAS2A1,
NGC1333-IRAS4A2, NGC1333-IRAS4B1, and SVS13-A. The NGC1333 star forming region
looks particularly glycolaldehyde rich, with a rate of occurrence up to 60%.
The glycolaldehyde spatial distribution overlaps with the continuum one,
tracing the inner 100 au around the protostar. A large number of lines (up to
18), with upper-level energies Eu from 37 K up to 375 K has been detected. We
derived column densities > 10^15 cm^-2 and rotational temperatures Trot between
115 K and 236 K, imaging for the first time hot-corinos around NGC1333-IRAS4B1
and SVS13-A. Conclusions: In multiple systems glycolaldehyde emission is
detected only in one component. The case of the SVS13-A+B and IRAS4-A1+A2
systems support that the detection of glycolaldehyde (at least in the present
Perseus sample) indicates older protostars (i.e. SVS13-A and IRAS4-A2), evolved
enough to develop the hot-corino region (i.e. 100 K in the inner 100 au).
However, only two systems do not allow us to firmly conclude whether the
primary factor leading to the detection of glycolaldehyde emission is the
environments hosting the protostars, evolution (e.g. low value of Lsubmm/Lint),
or accretion luminosity (high Lint).Comment: A&A, in pres
CSF SerpinA1 in Creutzfeldt\u2013Jakob disease and frontotemporal lobar degeneration
Objective: SerpinA1 (alpha-1 antitrypsin) is an acute inflammatory protein, which seems to play a role in neurodegeneration and neuroinflammation. In Alzheimer\u2019s disease and synucleinopathies, SerpinA1 is overexpressed in the brain and the cerebrospinal fluid (CSF) showing abnormal patterns of its charge isoforms. To date, no comprehensive studies explored SerpinA1 CSF isoforms in Creutzfeldt\u2013Jakob disease (CJD) and frontotemporal lobar degeneration (FTLD). Methods: Using a capillary isoelectric focusing immunoassay, we analyzed CSF SerpinA1 isoforms in control cases (n = 31) and patients with a definite or probable diagnosis of CJD (n=77) or FTLD (n = 30), belonging to several disease subtypes. Results: The overall SerpinA1 signal was significantly higher than in controls in CJD subtypes linked to abnormal prion protein (PrPSc) type 1, such as sporadic CJD (sCJD) MM(V)1, and in FTLD-TDP. Moreover, CJD linked to PrPSc type 1 and FTLD-TAU groups showed a significant relative increase of acidic and basic isoforms in comparison with controls, thereby forming two distinct SerpinA1 isoform profiles. Interpretation: CJD linked to PrPSc type 1 and FTLD show a differential upregulation and post-translational modifications of CSF SerpinA1. Further studies are needed to clarify whether these findings may reflect a common, albeit disease-specific, pathogenetic mechanism related to neurodegeneration
Relevance of d-D interactions on neutron and tritium production in IFMIF-EVEDA accelerator prototype
In the IFMIF-EVEDA accelerator prototype, deuterium is implanted in the components due to beam losses and in the beam dump, where the beam is stopped. The interaction of the deuterons with the deuterium previously implanted leads to the production of neutrons and tritium, which are important issues for radioprotection and safety analysis. A methodology to assess these production pathways in more realistic approach has been developed. The new tools and their main achievement are: (i) an “effective diffusivity coefficient” (deduced from available experimental data) that enables simulation of the diffusion phase, and (ii) the MCUNED code (able to handle deuteron transport libraries) allows to simulate the transport-slowdown of deuteron/tritium (to get the concentration profiles) and the neutron/tritium productions from d-Cu and d-D for up to 9 MeV incident deuteron. The results with/without theses tools are presented and their effect on the relevance of d-D sources versus d-Cu is evaluated
Удосконалення системи планування та контролю діяльності підприємства в умовах ринкової економіки
PACS and SPIRE photometer maps of M33: First results of the Herschel M33 extended survey (HERM33ES)
Within the framework of the HERM33ES key project, we are studying the star
forming interstellar medium in the nearby, metal-poor spiral galaxy M33,
exploiting the high resolution and sensitivity of Herschel. We use PACS and
SPIRE maps at 100, 160, 250, 350, and 500 micron wavelength, to study the
variation of the spectral energy distributions (SEDs) with galacto-centric
distance. Detailed SED modeling is performed using azimuthally averaged fluxes
in elliptical rings of 2 kpc width, out to 8 kpc galacto-centric distance.
Simple isothermal and two-component grey body models, with fixed dust
emissivity index, are fitted to the SEDs between 24 and 500 micron using also
MIPS/Spitzer data, to derive first estimates of the dust physical conditions.
The far-infrared and submillimeter maps reveal the branched, knotted spiral
structure of M33. An underlying diffuse disk is seen in all SPIRE maps (250-500
micron). Two component fits to the SEDs agree better than isothermal models
with the observed, total and radially averaged flux densities. The two
component model, with beta fixed at 1.5, best fits the global and the radial
SEDs. The cold dust component clearly dominates; the relative mass of the warm
component is less than 0.3% for all the fits. The temperature of the warm
component is not well constrained and is found to be about 60K plus/minus 10K.
The temperature of the cold component drops significantly from about 24K in the
inner 2 kpc radius to 13K beyond 6 kpc radial distance, for the best fitting
model. The gas-to-dust ratio for beta=1.5, averaged over the galaxy, is higher
than the solar value by a factor of 1.5 and is roughly in agreement with the
subsolar metallicity of M33.Comment: 5 pages, 3 figures, accepted for publication in the A&A Herschel
Special Issu
Star Forming Dense Cloud Cores in the TeV {\gamma}-ray SNR RX J1713.7-3946
RX J1713.7-3946 is one of the TeV {\gamma}-ray supernova remnants (SNRs)
emitting synchrotron X rays. The SNR is associated with molecular gas located
at ~1 kpc. We made new molecular observations toward the dense cloud cores,
peaks A, C and D, in the SNR in the 12CO(J=2-1) and 13CO(J=2-1) transitions at
angular resolution of 90". The most intense core in 13CO, peak C, was also
mapped in the 12CO(J=4-3) transition at angular resolution of 38". Peak C shows
strong signs of active star formation including bipolar outflow and a
far-infrared protostellar source and has a steep gradient with a
r^{-2.20.4} variation in the average density within radius r. Peak C and
the other dense cloud cores are rim-brightened in synchrotron X rays,
suggesting that the dense cloud cores are embedded within or on the outer
boundary of the SNR shell. This confirms the earlier suggestion that the X rays
are physically associated with the molecular gas (Fukui et al. 2003). We
present a scenario where the densest molecular core, peak C, survived against
the blast wave and is now embedded within the SNR. Numerical simulations of the
shock-cloud interaction indicate that a dense clump can indeed survive shock
erosion, since shock propagation speed is stalled in the dense clump.
Additionally, the shock-cloud interaction induces turbulence and magnetic field
amplification around the dense clump that may facilitate particle acceleration
in the lower-density inter-clump space leading to the enhanced synchrotron X
rays around dense cores.Comment: 22 pages, 7 figures, to accepted in The Astrophysical Journal. A full
color version with higher resolution figures is available at
http://www.a.phys.nagoya-u.ac.jp/~sano/ApJ10/ms_sano.pd
Cool and warm dust emission from M33 (HerM33es)
We study the far-infrared emission from the nearby spiral galaxy M33 in order
to investigate the dust physical properties such as the temperature and the
luminosity density across the galaxy. Taking advantage of the unique wavelength
coverage (100, 160, 250, 350 and 500 micron) of the Herschel Space Observatory
and complementing our dataset with Spitzer-IRAC 5.8 and 8 micron and
Spitzer-MIPS 24 and 70 micron data, we construct temperature and luminosity
density maps by fitting two modified blackbodies of a fixed emissivity index of
1.5. We find that the 'cool' dust grains are heated at temperatures between 11
and 28 K with the lowest temperatures found in the outskirts of the galaxy and
the highest ones in the center and in the bright HII regions. The
infrared/submillimeter total luminosity (5 - 1000 micron) is estimated to be
1.9x10^9 Lsun. 59% of the total luminosity of the galaxy is produced by the
'cool' dust grains (~15 K) while the rest 41% is produced by 'warm' dust grains
(~55 K). The ratio of the cool-to-warm dust luminosity is close to unity
(within the computed uncertainties), throughout the galaxy, with the luminosity
of the cool dust being slightly enhanced in the center of the galaxy.
Decomposing the emission of the dust into two components (one emitted by the
diffuse disk of the galaxy and one emitted by the spiral arms) we find that the
fraction of the emission in the disk in the mid-infrared (24 micron) is 21%,
while it gradually rises up to 57% in the submillimeter (500 micron). We find
that the bulk of the luminosity comes from the spiral arm network that produces
70% of the total luminosity of the galaxy with the rest coming from the diffuse
dust disk. The 'cool' dust inside the disk is heated at a narrow range of
temperatures between 18 and 15 K (going from the center to the outer parts of
the galaxy).Comment: 12 pages, 14 figures, accepted for publication in A&
Хроматоденситометрическое изучение листьев брусники обыкновенной (Vaccinium vitis-idaea L.)
VACCINIUMБРУСНИКАРАСТЕНИЙ ЛИСТЬЯРАСТЕНИЯ СТРУКТУРНЫЕ ЧАСТИ НАДЗЕМНЫЕАРБУТИНХРОМАТОГРАФИЯ ЖИДКОСТНАЯ /ИСПХРОМАТОДЕНСИТОМЕТРИЧЕСКИЙ СПОСОБХРОМАТОГРАФИЧЕСКАЯ ЗОНАХРОМАТОГРАММАРАСТЕНИЙ ЭКСТРАКТЫРЕАКТИВ ГИББСАЛИНЕЙНАЯ ЗАВИСИМОСТЬПроанализированы листья брусники обыкновенной, заготовленные в местах естественного произрастания в окрестностях г. Витебска Республики Беларусь. С помощью хроматоденситометрического способа изучались условия проведения хроматоденситометрического определения арбутина в листьях брусники. Подобраны система растворителей, концентрация реагента-проявителя (реактив Гиббса) для хроматоденситометрического способа определения арбутина в листьях брусники обыкновенной. Изучен характер зависимости цветометрических характеристик пятен арбутина от его количества в хроматографической зоне. Выявлена линейная зависимость цветометрических характеристик зон арбутина от его количества в хроматографической зоне. Было проведено сравнение хроматоденситометрического способа определения арбутина в листьях брусники с методом ВЭЖХ. Установлено, что результаты ВЭЖХ сопоставимы с результатами хроматоденситометрического способа определения арбутина в листьях брусники обыкновенной, что дает основание сделать вывод о достаточно высокой точности хроматоденситометрического способа и делает возможным его применение для качественного и количественного определения арбутина в листьях брусники. Изучались различные условия экстракции арбутина из листьев брусники обыкновенной. Построены графики зависимости полноты экстракции арбутина из листьев брусники обыкновенной при различных условиях экстракции. Подобраны оптимальные условия экстракции арбутина (степень измельченности листьев брусники –2 мм, время экстракции – 40 минут, экстрагент – вода).The leaves of common lingonberry harvested in the places of its natural growth in the vicinity of the city of Vitebsk of the Republic of Belarus have been analyzed using the chromatodensitometric method. The conditions of the chromatodensitometric method use for determining arbutin in the common lingonberry leaves have been studied. The solvent system, the concentration of the reagent- developer (Gibbs reagent) for the chromatodensitometric method used to determine arbutin in the common lingonberry leaves have been selected. The character of the dependence of the colorimetric characteristics of arbutin spots on its quantity in the chromatographic zone has been studied. A linear dependence of the colorimetric characteristics of arbutin zones on its quantity in the chromatographic zone has been revealed. The chromatodensitometric method of the determination of arbutin in the common lingonberry leaves has been compared to that of HPLC. It has been established that the HPLC results are comparable with those obtained by means of the chromatodensitometric method of determining arbutin in the common lingonberry leaves, which gives grounds to conclude that the chromatodensitometric method is rather accurate and may be used for the quantitative and qualitative determination of arbutin in the common lingonberry leaves. Various conditions for the extraction of arbutin from the leaves of common lingonberry have been studied. The graphs of the dependence of the completeness of the common lingonberry leaves arbutin extraction under various extraction conditions have been constructed. Optimal conditions for the extraction of arbutin have been selected (the degree of crushing the lingonberry leaves – 2 mm, extraction time – 40 minutes, the extractant – water)
Multiclass prediction of different dementia syndromes based on multi-centric volumetric MRI imaging
IntroductionDementia syndromes can be difficult to diagnose. We aimed at building a classifier for multiple dementia syndromes using magnetic resonance imaging (MRI).MethodsAtlas-based volumetry was performed on T1-weighted MRI data of 426 patients and 51 controls from the multi-centric German Research Consortium of Frontotemporal Lobar Degeneration including patients with behavioral variant frontotemporal dementia, Alzheimer’s disease, the three subtypes of primary progressive aphasia, i.e., semantic, logopenic and nonfluent-agrammatic variant, and the atypical parkinsonian syndromes progressive supranuclear palsy and corticobasal syndrome. Support vector machine classification was used to classify each patient group against controls (binary classification) and all seven diagnostic groups against each other in a multi-syndrome classifier (multiclass classification).ResultsThe binary classification models reached high prediction accuracies between 71 and 95% with a chance level of 50%. Feature importance reflected disease-specific atrophy patterns. The multi-syndrome model reached accuracies of more than three times higher than chance level but was far from 100%. Multi-syndrome model performance was not homogenous across dementia syndromes, with better performance in syndromes characterized by regionally specific atrophy patterns. Whereas diseases generally could be classified vs controls more correctly with increasing severity and duration, differentiation between diseases was optimal in disease-specific windows of severity and duration.DiscussionResults suggest that automated methods applied to MR imaging data can support physicians in diagnosis of dementia syndromes. It is particularly relevant for orphan diseases beside frequent syndromes such as Alzheimer’s disease
Relationship of serum beta-synuclein with blood biomarkers and brain atrophy
Background: Recent data support beta-synuclein as a blood biomarker to study synaptic degeneration in Alzheimer's disease (AD). Methods: We provide a detailed comparison of serum beta-synuclein immunoprecipitation - mass spectrometry (IP-MS) with the established blood markers phosphorylated tau 181 (p-tau181) (Simoa) and neurofilament light (NfL) (Ella) in the German FTLD consortium cohort (n = 374) and its relation to brain atrophy (magnetic resonance imaging) and cognitive scores. Results: Serum beta-synuclein was increased in AD but not in frontotemporal lobar degeneration (FTLD) syndromes. Beta-synuclein correlated with atrophy in temporal brain structures and was associated with cognitive impairment. Serum p-tau181 showed the most specific changes in AD but the lowest correlation with structural alterations. NfL was elevated in all diseases and correlated with frontal and temporal brain atrophy. Discussion: Serum beta-synuclein changes differ from those of NfL and p-tau181 and are strongly related to AD, most likely reflecting temporal synaptic degeneration. Beta-synuclein can complement the existing panel of blood markers, thereby providing information on synaptic alterations. Highlights: Blood beta-synuclein is increased in Alzheimer's disease (AD) but not in frontotemporal lobar degeneration (FTLD) syndromes. Blood beta-synuclein correlates with temporal brain atrophy in AD. Blood beta-synuclein correlates with cognitive impairment in AD. The pattern of blood beta-synuclein changes in the investigated diseases is different to phosphorylated tau 181 (p-tau181) and neurofilament light (NfL)
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