216 research outputs found

    Radio Lobes of Pictor A: an X-ray spatially resolved Study

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    A new XMM observation has made possible a detailed study of both lobes of the radio galaxy Pictor A. Their X-ray emission is of non thermal origin and due to Inverse Compton scattering of the microwave background photons by relativistic electrons in the lobes, as previously found. In both lobes, the equipartition magnetic field (Beq) is bigger than the Inverse Compton value (Bic), calculated from the radio and X-ray flux ratio. The Beq/Bic ratio never gets below 2, in spite of the large number of reasonable assumptions tested to calculate Beq, suggesting a lobe energetic dominated by particles. The X-ray data quality is good enough to allow a spatially resolved analysis. Our study shows that Bic varies through the lobes. It appears to increase behind the hot spots. On the contrary, a rather uniform distribution of the particles is observed. As a consequence, the radio flux density variation along the lobes appears to be mainly driven by magnetic field changes.Comment: 15 pages, 3 figures, ApJ accepte

    Low frequency follow up of radio halos and relics in the GMRT Radio Halo Cluster Survey

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    We performed GMRT low frequency observations of the radio halos, relics and new candidates belonging to the GMRT Radio Halo Cluster Sample first observed at 610 MHz. High sensitivity imaging was performed using the GMRT at 325 MHz and 240 MHz. The properties of the diffuse emission in each cluster were compared to our 610 MHz images and/or literature information available at other frequencies, in order to derive the integrated spectra over a wide frequency range.Beyond the classical radio halos, whose spectral index őĪ\alpha is in the range ‚ąľ1.2√∑1.3\sim1.2\div1.3 (S‚ąĚőĹ‚ąíőĪ\propto\nu^{-\alpha}), we found sources with őĪ‚ąľ1.6√∑1.9\alpha\sim1.6\div1.9. This result supports the idea that the spectra of the radiating particles in radio halos is not universal, and that inefficient mechanisms of particle acceleration are responsible for their origin. We also found a variety of brightness distributions, i.e. centrally peaked as well as clumpy halos. Even though the thermal and relativistic plasma tend to occupy the same cluster volume, in some cases a positional shift between the radio and X-ray peaks of emission is evident. Our observations also revealed the existence of diffuse cluster sources which cannot be easily classified either as halos or relics. New candidate relics were found in A1300 and in A1682, and in some clusters "bridges" of radio emission have been detected, connecting the relic and radio halo emission. Combining our new data with literature information, we derived the LogLX_{\rm X}-LogP325MHz_{\rm 325 MHz} correlation for radio halos, and investigated the possible trend of the spectral index of radio halos with the temperature of the intracluster medium.Comment: 19 pages, 10 figures, 5 tables, accepted for publication on A&

    Default Mode Network alterations in alexithymia: An EEG power spectra and connectivity study

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    Recent neuroimaging studies have shown that alexithymia is characterized by functional alterations in different brain areas [e.g., posterior cingulate cortex (PCC)], during emotional/social tasks. However, only few data are available about alexithymic cortical networking features during resting state (RS). We have investigated the modifications of electroencephalographic (EEG) power spectra and EEG functional connectivity in the default mode network (DMN) in subjects with alexithymia. Eighteen subjects with alexithymia and eighteen subjects without alexithymia matched for age and gender were enrolled. EEG was recorded during 5 min of RS. EEG analyses were conducted by means of the exact Low Resolution Electric Tomography software (eLORETA). Compared to controls, alexithymic subjects showed a decrease of alpha power in the right PCC. In the connectivity analysis, compared to controls, alexithymic subjects showed a decrease of alpha connectivity between: (i) right anterior cingulate cortex and right PCC, (ii) right frontal lobe and right PCC, and (iii) right parietal lobe and right temporal lobe. Finally, mediation models showed that the association between alexithymia and EEG connectivity values was directed and was not mediated by psychopathology severity. Taken together, our results could reflect the neurophysiological substrate of some core features of alexithymia, such as the impairment in emotional awareness

    Gene Therapy for Mitochondrial Diseases: Current Status and Future Perspective

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    Mitochondrial diseases (MDs) are a group of severe genetic disorders caused by mutations in the nuclear or mitochondrial genome encoding proteins involved in the oxidative phosphorylation (OXPHOS) system. MDs have a wide range of symptoms, ranging from organ-specific to multisystemic dysfunctions, with different clinical outcomes. The lack of natural history information, the limits of currently available preclinical models, and the wide range of phenotypic presentations seen in MD patients have all hampered the development of effective therapies. The growing number of pre-clinical and clinical trials over the last decade has shown that gene therapy is a viable precision medicine option for treating MD. However, several obstacles must be overcome, including vector design, targeted tissue tropism and efficient delivery, transgene expression, and immunotoxicity. This manuscript offers a comprehensive overview of the state of the art of gene therapy in MD, addressing the main challenges, the most feasible solutions, and the future perspectives of the field

    Curation of a reference database of COI sequences for insect identification through DNA metabarcoding: COins

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    DNA metabarcoding is a widespread approach for the molecular identification of organisms. While the associated wet-lab and data processing procedures are well established and highly efficient, the reference databases for taxonomic assignment can be implemented to improve the accuracy of identifications. Insects are among the organisms for which DNA-based identification is most commonly used; yet, a DNA-metabarcoding reference database specifically curated for their species identification using software requiring local databases is lacking. Here, we present COins, a database of 5' region cytochrome c oxidase subunit I sequences (COI-5P) of insects that includes over 532‚ÄČ000 representative sequences of >106‚ÄČ000 species specifically formatted for the QIIME2 software platform. Through a combination of automated and manually curated steps, we developed this database starting from all COI sequences available in the Barcode of Life Data System for insects, focusing on sequences that comply with several standards, including a species-level identification. COins was validated on previously published DNA-metabarcoding sequences data (bulk samples from Malaise traps) and its efficiency compared with other publicly available reference databases (not specific for insects). COins can allow an increase of up to 30% of species-level identifications and thus can represent a valuable resource for the taxonomic assignment of insects' DNA-metabarcoding data, especially when species-level identification is needed https://doi.org/10.6084/m9.figshare.19130465.v1

    Altitudinal training sets of pollen rain ‚Äď vegetation cover and modelled climate as a tool for the interpretation of paleoecological records

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    To improve our ability to reconstruct past environments and climate from fossil pollen records, modern proxy calibration studies along climatic and ecological gradients are needed. Here we present the first training set of modern pollen rain, vegetation, climate and terrain parameters developed along a 1700m-high transect in the western Italian Alps. The accurate knowledge on the relationships between these factors is essential for robust and sound reconstructions of past ecosystems based on microscopic plant remains

    A shock front in the merging galaxy cluster Abell 754: X-ray and radio observations

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    We present new Chandra X-ray and Giant Meterwave Radio Telescope (GMRT) radio observations of the nearby merging galaxy cluster Abell 754. Our X-ray data confirm the presence of a shock front by obtaining the first direct measurement of a gas temperature jump across the X-ray brightness edge previously seen in the imaging data. A754 is only the fourth galaxy cluster with confirmed merger shock fronts, and it has the weakest shock of those, with a Mach number M=1.57+0.16-0.12. In our new GMRT observation at 330 MHz, we find that the previously-known centrally located radio halo extends eastward to the position of the shock. The X-ray shock front also coincides with the position of a radio relic previously observed at 74 MHz. The radio spectrum of the post-shock region, using our radio data and the earlier results at 74 MHz and 1.4 GHz, is very steep. We argue that acceleration of electrons at the shock front directly from thermal to ultrarelativistic energies is problematic due to energy arguments, while reacceleration of preexisting relativistic electrons is more plausible.Comment: 10 pages, 8 figures, "emulateapj" format. Submitted to Ap

    Factors affecting soil invertebrate biodiversity in agroecosystems of the Po Plain area (Italy)

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    Soil is a fundamental component of the biosphere, whose properties and quality are affected by human activities, such as agriculture. Soil health is fundamental for different ecosystem services and soil biota has a crucial role in maintaining it. Elucidating how different crops and agricultural practices affect soil invertebrates communities is of relevance. In the present study, a DNA metabarcoding approach was adopted to evaluate the effects of different biotic and abiotic factors, including agricultural practices, on the composition and diversity of soil invertebrate communities of different agro-ecosystems (Po Plain-Italy). At this aim, the DNA markers and the more effective primers in retrieving soil metazoan communities were established. Bulk soil samples from different agro-ecosystems (i.e., cornfield, alfalfa, paddy fields, vineyard, stable meadow, woodland) were collected and, processed for obtaining 18S rRNA and coi sequences (raw reads analyzed using QIIME2 and R). Soil physical and chemical parameters were measured for each soil sample (e.g., pH, carbon-nitrogen ratio, texture, porosity) and metadata on farms management were retrieved. The most efficient primer pairs in recovering soil metazoans were M620F/M1260R for 18S rRNA, and mlCOIintF/jgHCO2198R for coi gene. Soil communities resulted dominated by Nematoda, Arthropoda, Annelida, Rotifera and Tardigrada. The most diverse invertebrate communities have been found in the soil of stable meadows and woodlands, while cornfields showed the lowest level of diversity. The diversity of soil invertebrate communities (Hill numbers) was positively correlated with the level of porosity and carbon-nitrogen ratio, while it was negatively correlated with the phosphate abundance. This pattern probably reflects the negative effect of excessive fertilization with phosphates on soil fauna, while the abundance of organic matter and microhabitats were found to enhance the presence of more complex communities. Other soil properties were correlated only with specific taxa (e.g., pH was negatively correlated with the diversity of Annelida and Rotifera)

    Near-infrared quantum dots labelled with a tumor selective tetrabranched peptide for in vivo imaging

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    Near-infrared quantum dots (NIR QDs) are a new class of fluorescent labels with excellent bioimaging features, such as high fluorescence intensity, good fluorescence stability, sufficient electron density, and strong tissue-penetrating ability. For all such features, NIR QDs have great potential for early cancer diagnosis, in vivo tumor imaging and high resolution electron microscopy studies on cancer cells

    Antimicrobial peptides active in in vitro models of endodontic bacterial infections modulate inflammation in human cardiac fibroblasts

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    Endodontic and periodontal disease are conditions of infectious origin that can lead to tooth loss or develop into systemic hyperinflammation, which may be associated with a wide variety of diseases, including cardiovascular. Endodontic and periodontal treatment often relies on antibiotics. Since new antimicrobial resistances are a major threat, the use of standard antibiotics is not recommended when the infection is only local. Antimicrobial peptides were recently demonstrated to be valid alternatives for dental treatments. The antimicrobial peptide M33D is a tetrabranched peptide active against Gram-negative and Gram-positive bacteria. It has a long life, unusual for peptides, because its branched form provides resistance to proteases. Here the efficacy of M33D and of its analog M33i/l as antibiotics for local use in dentistry was evaluated. M33D and M33i/l were active against reference strains and multidrug-resistant clinical isolates of Gram-negative and Gram-positive species. Their minimum inhibitory concentration against different strains of dental interest was between 0.4 and 6.0 mu M. Both peptides acted rapidly on bacteria, impairing membrane function. They also disrupted biofilm effectively. Disinfection of the root canal is crucial for endodontic treatments. M33D and M33i/l reduced E. faecalis colonies to one-twentieth in a dentin slices model reproducing root canal irrigation. They both captured and neutralized lipopolysaccharide (LPS), a bacterial toxin responsible for inflammation. The release of IL-1 beta and TNF alpha by LPS-stimulated murine macrophages was reduced by both peptides. Human cardiac fibroblasts respond to different insults with the release of proinflammatory cytokines, and consequently, they are considered directly involved in atherogenic cardiovascular processes, including those triggered by infections. The presence of M33D and M33i/l at MIC concentration reduced IL6 release from LPS- stimulated human cardiac fibroblasts, hence proving to be promising in preventing bacteria-induced atherogenesis. The two peptides showed low toxicity to mammalian cells, with an EC50 one order of magnitude higher than the average MIC and low hemolytic activity. The development of antimicrobial peptides for dental irrigations and medication is a very promising new field of research that will provide tools to fight dental infections and their severe consequences, while at the same time protecting standard antibiotics from new outbreaks of antimicrobial resistance. © 2022 by the authors
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