743 research outputs found
Correlated Component Analysis for diffuse component separation with error estimation on simulated Planck polarization data
We present a data analysis pipeline for CMB polarization experiments, running
from multi-frequency maps to the power spectra. We focus mainly on component
separation and, for the first time, we work out the covariance matrix
accounting for errors associated to the separation itself. This allows us to
propagate such errors and evaluate their contributions to the uncertainties on
the final products.The pipeline is optimized for intermediate and small scales,
but could be easily extended to lower multipoles. We exploit realistic
simulations of the sky, tailored for the Planck mission. The component
separation is achieved by exploiting the Correlated Component Analysis in the
harmonic domain, that we demonstrate to be superior to the real-space
application (Bonaldi et al. 2006). We present two techniques to estimate the
uncertainties on the spectral parameters of the separated components. The
component separation errors are then propagated by means of Monte Carlo
simulations to obtain the corresponding contributions to uncertainties on the
component maps and on the CMB power spectra. For the Planck polarization case
they are found to be subdominant compared to noise.Comment: 17 pages, accepted in MNRA
Hyaluronan Hydrogels: Rheology and Stability in Relation to the Type/Level of Biopolymer Chemical Modification
BDDE (1,4-butanediol-diglycidylether)-crosslinked hyaluronan (HA) hydrogels are widely used for dermo-aesthetic purposes. The rheology and stability of the gels under physiological conditions greatly affect their clinical indications and outcomes. To date, no studies investigating how these features are related to the chemistry of the polymeric network have been reported. Here, four available HA-BDDE hydrogels were studied to determine how and to what extent their rheology and stability with respect to enzymatic hydrolysis relate to the type and degree of HA structural modification.1 H-/13 C-NMR analyses were associated for the quantification of the âtrueâ HA chemical derivatization level, discriminating between HA that was effectively crosslinked by BDDE, and branched HA with BDDE that was anchored on one side. The rheology was measured conventionally and during hydration in a physiological medium. Sensitivity to bovine testicular hyaluronidase was quantified. The correlation between NMR data and gel rheology/stability was evaluated. The study indicated that (1) the gels greatly differed in the amounts of branched, crosslinked, and overall modified HA, with most of the HA being branched; (2) unexpectedly, the conventionally measured rheological properties did not correlate with the chemical data; (3) the gelsâ ranking in terms of rheology was greatly affected by hydration; (4) the rheology of the hydrated gels was quantitatively correlated with the amount of crosslinked HA, whereas the correlations with the total HA modification level and with the degree of branched HA were less significant; (5) increasing HA derivatization/crosslinking over 9/3 mol% did not enhance the stability with respect to hyaluronidases. These results broaden our knowledge of these gels and provide valuable information for improving their design and characterization
Estimating the spectral indices of correlated astrophysical foregrounds by a second-order statistical approach
We present the first tests of a new method, the Correlated Component Analysis
(CCA) based on second-order statistics, to estimate the mixing matrix, a key
ingredient to separate astrophysical foregrounds superimposed to the Cosmic
Microwave Background (CMB). In the present application, the mixing matrix is
parameterized in terms of the spectral indices of Galactic synchrotron and
thermal dust emissions, while the free-free spectral index is prescribed by
basic physics, and is thus assumed to be known. We consider simulated
observations of the microwave sky with angular resolution and white stationary
noise at the nominal levels for the PLANCK satellite, and realistic foreground
emissions, with a position dependent synchrotron spectral index. We work with
two sets of PLANCK frequency channels: the low frequency set, from 30 to 143
GHz, complemented with the Haslam 408 MHz map, and the high frequency set, from
217 to 545 GHz. The concentration of intense free-free emission on the Galactic
plane introduces a steep dependence of the spectral index of the global
Galactic emission with Galactic latitude, close to the Galactic equator. This
feature makes difficult for the CCA to recover the synchrotron spectral index
in this region, given the limited angular resolution of PLANCK, especially at
low frequencies. A cut of a narrow strip around the Galactic equator (|b|<3
deg), however, allows us to overcome this problem. We show that, once this
strip is removed, the CCA allows an effective foreground subtraction, with
residual uncertainties inducing a minor contribution to errors on the recovered
CMB power spectrum.Comment: 9 pages, 5 figures and 1 table accepted by MNRA
Ultrasound delivery of Surface Enhanced InfraRed Absorption active gold-nanoprobes into fibroblast cells: a biological study via Synchrotron-based InfraRed microanalysis at single cell level
Ultrasound (US) induced transient membrane permeabilisation has emerged as a hugely promising tool for the delivery of exogenous vectors through the cytoplasmic membrane, paving the way to
the design of novel anticancer strategies by targeting functional nanomaterials to specific biological sites. An essential step towards this end is the detailed recognition of suitably marked nanoparticles in sonoporated cells and the investigation of the potential related biological effects. By taking advantage of Synchrotron Radiation fourier transform infrared micro-spectroscopy (SR-microftiR) in providing highly sensitive analysis at the single cell level, we studied the internalisation of a nanoprobe within fibroblasts (NIH-3T3) promoted by low-intensity US. To this aim we employed 20 nm gold nanoparticles conjugated with the IR marker 4-aminothiophenol. The significant Surface Enhanced Infrared Absorption provided by the nanoprobes, with an absorbance increase up to two orders of magnitude, allowed us to efficiently recognise their inclusion within cells. Notably, the selective and stable SR- microftiR detection from single cells that have internalised the nanoprobe exhibited clear changes in both shape and intensity of the spectral profile, highlighting the occurrence of biological effects. Flow cytometry, immunofluorescence and murine cytokinesis-block micronucleus assays confirmed the presence of slight but significant cytotoxic and genotoxic events associated with the US-nanoprobe combined treatments. our results can provide novel hints towards US and nanomedicine combined strategies for cell spectral imaging as well as drug delivery-based therapies
Mycorrhizal activity and diversity in a long-term organic Mediterranean agroecosystem
In organic agriculture, soil fertility and productivity rely on biological processes carried out by soil microbes, which represent the key elements of agroecosystem functioning. Arbuscular mycorrhizal fungi (AMF), fundamental microorganisms for soil fertility, plant nutrition and health, may play an important role in organic agriculture by compensating for the reduced use of fertilizers and pesticides. Though, AMF activity and diversity following conversion from conventional to organic farming are poorly investigated. Here we studied AMF abundance, diversity and activity in short- and long-term organically and conventionally managed Mediterranean arable agroecosystems. Our results show that both AMF population activity, as assessed by the mycorrhizal inoculum potential (MIP) assay, the percentage of colonized root length of the field crop (maize) and glomalin-related soil protein (GRSP) content were higher in organically managed fields and increased with time since transition to organic farming. Here, we showed an increase of GRSP content in arable organic systems and a strong correlation with soil MIP values. The analysis of AMF spores showed differences among communities of the three microagroecosystems in terms of species richness and composition as suggested by a multivariate analysis. All our data indicate that AMF respond positively to the transition to organic farming by a progressive enhancement of their activity that seems independent from the species richness of the AMF communities. Our study contributes to the understanding of the effects of agricultural managements on AMF, which represent a promising tool for the implementation of sustainable agriculture
Microbiological-chemical sourced chondroitin sulfates protect neuroblastoma SH-SY5Y cells against oxidative stress and are suitable for hydrogel-based controlled release
Chondroitin sulfates (CS) are a class of sulfated glycosaminoglycans involved in many biological processes. Several studies reported their protective effect against neurodegenerative conditions like Alzheimerâs disease. CS are commonly derived from animal sources, but ethi-cal concerns, the risk of contamination with animal proteins, and the difficulty in controlling the sulfation pattern have prompted research towards non-animal sources. Here we exploited two microbiological-chemical sourced CS (i.e., CS-A,C and CS-A,C,K,L) and Carbopol 974P NF/agarose semi-interpenetrating polymer networks (i.e., P.NaOH.0 and P.Ethanol.0) to set up a release system, and tested the neuroprotective role of released CS against H2 O2-induced oxidative stress. After assessing that our CS (1â100 ”M) require a 3 h pre-treatment for neuroprotection with SH-SY5Y cells, we evaluated whether the autoclave type (i.e., N-or B-type) affects hydrogel viscoelastic properties. We selected B-type autoclaves and repeated the study after loading CS (1 or 0.1 mg CS/0.5 mL gel). After loading 1 mg CS/0.5 mL gel, we evaluated CS release up to 7 days by 1,9-dimethylmethylene blue (DMMB) assay and verified the neuroprotective role of CS-A,C (1 ”M) in the supernatants. We observed that CS-A,C exhibits a broader neuroprotective effect than CS-A,C,K,L. Moreover, sulfation pattern affects not only neuroprotection, but also drug release
Clastogenicity and aneuploidy in newborn and adult mice exposed to 50 Hz magnetic fields.
Purpose:?To detect possible clastogenic and aneugenic properties of a 50 Hz, 650 ?T magnetic field. Materials and methods:?The micronucleus test with CREST (Calcinosis, Raynaud's phenomenon, Esophageal dismotility, Sclerodactility, Telangectasia) antibody staining was performed on liver and peripheral blood sampled from newborn mice exposed to an ELF (Extremely Low Frequency) magnetic field during the whole intra-uterine life (21 days), and on bone marrow and peripheral blood sampled from adult mice exposed to the same magnetic field for the same period. Results:?Data obtained in newborn mice show a significant increase in micronuclei frequencies. In absolute terms, most of the induced micronuclei were CREST-negative (i.e., formed by a chromosome fragment). However, in relative terms, ELF exposure caused a two-fold increase in CREST-negative micronuclei and a four-fold increase in CREST-positive micronuclei (i.e., formed by a whole chromosome). No significant effect was recorded on exposed adults. Conclusions:?These findings suggest the need for investigation of aneugenic properties of ELF magnetic fields in order to establish a possible relationship to carcinogenesis
Impact of nitrogen fertilization and soil tillage on arbuscular mycorrhizal fungal communities in a Mediterranean agroecosystem
The impact of nitrogen (N) fertilization and tillage on arbuscular mycorrhizal fungi (AMF) was studied in a Mediterranean arable system by combining molecular, biochemical and morphological analyses of field soil and of soil and roots from trap plants grown in microcosm. Canonical correspondence analysis (CCA) of PCRâDGGE banding patterns evidenced that AMF communities in the field are affected by N-fertilization and tillage. N-fertilization was also the main factor shaping AMF communities in Medicago sativa trap plant soil and roots. The overall sporulation pattern of the different AMF species showed a predominant effect of tillage on AMF communities, as shown by CCA analysis. Funneliformis mosseae was the predominant species sporulating in tilled soils, while Glomus viscosum and Glomus intraradices prevailed in no-tilled soils. Field glomalin-related soil protein content was reduced by tillage practices. Our multimodal approach, providing data on two main production factors affecting soil AMF communities, may help implementing effective agricultural management strategies able to support the beneficial relationship between crops and native AMF symbionts
Effect of cold drawing reduction rate on edge-to-center-characterized microstructure and orientation alongside residual stresses in conjunction with magnetic properties of low-carbon high-alloy ferromagnetic steel
In the current research, the effect of cold drawing reduction rate (CDRR) of 15% and 45% and the required subsequent isothermal static recrystallization annealing heat treatment (ISRAHT) on the microstructures, textures, residual stresses, and magnetic properties of ferritic/ferromagnetic stainless steel (FSS), EN 1.4106, are investigated by a series of experimental analyses. The study is carried out by the theoretical well-known model of Johnson-Mehl-Avrami-Kolmogorov (JMAK) in conjunction with aforesaid properties. According to the results, by increasing the CDRR, the recrystallization fractions (RF) become faster in accordance with the JMAK theory. Such an increment also affects more fragmented and elongated grains, which leads to provide smaller grains in size. However, by the effect of slow cooling process (SCP), the grain growth is another noticeable part of study. Likewise, the effects of CDRR and the subsequent ISRAHT find to be beneficial for the evolution of microstructures, textures, and relief of residual stresses, and better performance of magnetic behavior. For instance, higher relative magnetic permeabilities approximately above 1000 causes to reach residual stresses closer to zero. The cold-drawn FSSs are consisted of the α-fibre texture, which is close to {2 2 3} ă1 1 0ă and {1 1 1} ă1 1 0ă, with higher intensity while by gradual higher recrystallization, the orientation tendency to {1 1 1} ă0 1 1ă of Îł-fibre are formed following to the more distributed texture with lesser intensity. The findings display that while the recrystallization process addresses the formation of new grains, resulting in the more equiaxed grains, more well-aligned textures are also achieved in respect to the lower misorientation uniformity density and even with more distributed clusters
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