Aims. We derive the value of the dark matter density at the Sun’s location (ρ⊙) without fully modeling the mass distribution in the Galaxy. Methods. The proposed method relies on the local equation ...of centrifugal equilibrium and is independent of i) the shape of the dark matter density profile, ii) knowledge of the rotation curve from the galaxy center out to the virial radius, and iii) the uncertainties and the non-uniqueness of the bulge/disk/dark halo mass decomposition. Results. The result can be obtained in analytic form, and it explicitly includes the dependence on the relevant observational quantities and takes their uncertainties into account. By adopting the reference, state-of-the-art values for these, we find ρ⊙ = 0.43(11)(10) GeV/cm3, where the quoted uncertainties are respectively due to the uncertainty in the slope of the circular-velocity at the Sun location and the ratio between this radius and the length scale of the stellar exponential thin disk. Conclusions. We obtained a reliable estimate of ρ⊙, that, in addition has the merit of being ready to take any future change/improvement into account in the measures of the observational quantities it depends on.
In the current ΛCDM cosmological scenario, N-body simulations provide us with a universal mass profile, and consequently a universal equilibrium circular velocity of the virialized objects, as ...galaxies. In this paper we obtain, by combining kinematical data of their inner regions with global observational properties, the universal rotation curve of disc galaxies and the corresponding mass distribution out to their virial radius. This curve extends the results of Paper I, concerning the inner luminous regions of Sb–Im spirals, out to the edge of the galaxy haloes.
The growth of new therapeutic options and practices increases the risk of hepatitis B virus (HBV) reactivation in patients with haematologic malignancies and/or patients undergoing haematologic stem ...cell transplantation (HSCT).
To provide a systematic review supporting recommendations for prevention, monitoring, prophylaxis and therapy of HBV reactivation in patients with haematologic malignancies and HSCT.
The systematic review was based on a strategy using PubMed and the Cochrane Library searching literature published from 1991 to December 31, 2016. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines were followed.
Randomized control trials, prospective and retrospective cohort studies.
Cochrane Risk of Bias Tool and Newcastle Ottawa Quality Assessment Scale.
Forty-two studies of fair or good quality were included in this systematic review. The following main results were obtained: haematologic patients should be screened for HBV before chemotherapy; HBV DNA levels should be monthly monitored in all HBV-positive patients not receiving prophylaxis; hepatitis B surface antigen (HBsAg)-positive haematologic patients and patients undergoing HSCT should receive prophylaxis and third-generation HBV drugs should be provided; and anti–hepatitis B core protein–positive lymphoma patients and patients who underwent HSCT should receive antiviral prophylaxis.
A higher quality of evidence is needed. However, the level of evidence was sufficient to support the recommendations published in this issue of the journal.
•Biomass origin and structure affect composition and yield of pyrolysis biochar.•Operating conditions of thermal treatment affect composition and yield of pyrolysis biochar.•Further pyrolysis ...reactions modify young biochar structure and release gas products.•A predictive kinetic mechanism of biomass pyrolysis accounts for all these effects.•Large collection of literature experimental data supports the validation of the kinetic mechanism.
Biomass is increasingly being recognized as a promising carrier for both heat, energy and chemicals production. However, several aspects still require intense research activity towards a better design and optimization of industrial combustors, gasifiers and pyrolyzer. The objective of this work is to update the CRECK kinetic mechanism of biomass pyrolysis, allowing a better prediction of both yield and composition of the solid residue (biochar). Moreover, further model modifications allow to better describe the variability of hemicellulose in different biomass. To this end, a large set of literature experimental data is collected and organized into a database, which is used to further tune and validate the proposed kinetic mechanism. Although the kinetic model maintains the previous agreement in respect of the rate of biomass pyrolysis, formation and distribution of gas and tar products, the novelty of this work is the greater attention to the predictions of biochar yield and composition, in a wide range of operative conditions. The model describes the solid residue as a mixture of pure carbon together with lumped metaplastic compounds, which represent the whole range of oxygenated and hydrogenated groups bonded to the carbonaceous matrix. These metaplastic species are released to the gas phase with their own kinetics and describe the change of both mass loss and elemental composition of the biochar. These comprehensive predictions of biochar composition are crucial for an accurate description of the successive oxidation and gasification processes.
Behavioral studies in humans and electrophysiological recordings in nonhuman primates have suggested the existence of a specific representation of the space immediately surrounding the body. In ...macaques, neurons that have visual receptive fields limited to a region of space close around a body part have been found in premotor and parietal areas. These cells are hypothesized to encode the location of external objects in coordinate systems that are centered on individual body parts. In the present study, we used an fMRI adaptation paradigm on healthy participants to reveal areas in the anterior part of the intraparietal sulcus, the inferior parietal lobe (supramarginal gyrus), and the dorsal and ventral portions of the premotor cortex that exhibit selective BOLD adaptation to an object moving near the right hand. Crucially, these areas did not manifest adaptation if the stimulus was presented in far space (100 cm) or when the hand was retracted from the object. This hand-centered selectivity could not be detected when a traditional fMRI analysis approach was used. These findings are important as they provide the most conclusive neuroimaging evidence to date for a representation of near-personal space in the human brain. They also demonstrate a selective mechanism implemented by human perihand neurons in the premotor and posterior parietal areas and add to earlier findings from humans and nonhuman primates.
Recent cosmological hydrodynamical simulations suggest that baryonic processes, and in particular supernova feedback following bursts of star formation, can alter the structure of dark matter haloes ...and transform primordial cusps into shallower cores. To assess whether this mechanism offers a solution to the long-standing cusp-core controversy, simulated haloes must be compared to real dark matter haloes inferred from galaxy rotation curves. For this purpose, two new dark matter density profiles were recently derived from simulations of galaxies in complementary mass ranges: the DC14 halo (1010 < Mhalo/M⊙ < 8 × 1011) and the coreNFW halo (107 < Mhalo/M⊙ < 109). Both models have individually been found to give good fits to observed rotation curves. For the DC14 model, however, the agreement of the predicted halo properties with cosmological scaling relations was confirmed by one study, but strongly refuted by another. A next important question is whether, despite their different approaches, the two models converge to the same solution in the mass range where both should be appropriate. To investigate this, we tested the DC14 and coreNFW halo models on the rotation curves of a selection of galaxies with halo masses in the range 4 × 109M⊙ – 7 × 1010M⊙ and compared their predictions. We further applied the DC14 model to a set of rotation curves at higher halo masses, up to 9 × 1011M⊙, to verify the agreement with the cosmological scaling relations. Both models are generally able to reproduce the observed rotation curves, in line with earlier results, and the predicted dark matter haloes are consistent with the cosmological c−Mhalo and M∗−Mhalo relations. We find that the DC14 and coreNFW models are also in fairly good agreement with each other, even though DC14 tends to predict slightly less extended cores and somewhat more concentrated haloes than coreNFW. While the quality of the fits is generally similar for both halo models, DC14 does perform significantly better than coreNFW for three galaxies. In each of these cases, the problem for coreNFW is related to connection of the core size to the stellar half-mass radius, although we argue that it is justifiable to relax this connection for NGC 3741. A larger core radius brings the coreNFW model for this galaxy in good agreement with the data and the DC14 model.
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•The cellulose is used as reactive filler in the synthesis of polyurethane foams.•The cellulose is used to tune the chemico-physical and mechanical properties of foams.•Two topologies ...of cellulose were used: crystalline and amorphous.•A reduction of the thermal conductivity of 33% is obtained with amorphous cellulose.•The amorphous cellulose modifies the mechanical behavior from rigid to semi-rigid.
Cystalline-Cc and ultra-milled Amorphous-Ca cellulose were used as reactive filler to tune the performances of composite polyurethane-cellulose-foams, PUC. The effect of Cc and Ca on chemo-physical and mechanical properties of PUC was analysed through FTIR, morphological analysis, thermal conductivity and compression measurements. FTIR results show that, both Cc and Ca react with isocyanate through the OH functional groups contributing to the formation of a tough cellulose-polyurethane network. Morphological observations show that the addition of both Cc and Ca induces a decrease of average cell-size compared to the pristine-PU, thus confirming that they act as nucleating agent. In addition, the better dispersion of the Ca in the polyol, with respect to Cc induces, a finer cell leading to a reduction of the thermal conductivity around 33 % (for the composite loaded with 20 %wt-Ca) with respect to pristine-PU. Finally, the addition of Ca highly reactive modifies the mechanical behaviour from rigid-brittle to semi-rigid.
We present, for five spiral galaxies, H i data which, along with the Ha rotation curves, are used to derive the distribution of dark matter within these objects. A new method for extracting rotation ...curves from H i data cubes is presented, which takes into account the existence of a warp and minimizes projection effects. The rotation curves obtained are tested by taking them as input in the construction of model data cubes that are compared with the observed ones: the agreement is excellent. Model data cubes built using rotation curves obtained with standard methods, such as the first-moment analysis, however, fail the test. The H i rotation curves agree well with the Ha data, where they coexist. Moreover, the combined Ha+ H i rotation curves are smooth, symmetric and extend to large radii. The rotation curves are decomposed into stellar, gaseous and dark matter contributions, and the inferred density distribution is compared with various mass distributions: dark haloes with a central density core,cold dark matter (CDM) haloes (NFW and Moore profiles), H i scaling and MOND. The observations point to haloes with constant-density cores of size rcore∼ropt and central densities scaling approximately as 0r-2/3core. CDM models (which predict a central cusp in the density profile) are in clear conflict with the data. H i scaling and MOND cannot account for the observed kinematics: we find some counter-examples.
Humans are estimated to consume several grams per week of nanoplastics (NPs) through exposure to a variety of contamination sources. Nonetheless, the effects of these polymeric particles on living ...systems are still mostly unknown. Here, by means of CD, NMR and TEM analyses, we describe at an atomic resolution the interaction of ubiquitin with polystyrene NPs (PS-NPs), showing how a hard protein corona is formed. Moreover, we report that in human HeLa cells exposure to PS-NPs leads to a sensible reduction of ubiquitination. Our study overall indicates that PS-NPs cause significant structural effects on ubiquitin, thereby influencing one of the key metabolic processes at the base of cell viability.
A high-resolution study of ubiquitin-polystyrene nanoparticle (PS-NP) interaction is reported. We also show the effects of PS-NPs on ubiquitination in HeLa cells.
Recent high-resolution N-body CDM simulations indicate that nonsingular three-parameter models such as the Einasto profile perform better than the singular two-parameter models, e.g. the Navarro, ...Frenk and White, in fitting a wide range of dark matter haloes. While many of the basic properties of the Einasto profile have been discussed in previous studies, a number of analytical properties are still not investigated. In particular, a general analytical formula for the surface density, an important quantity that defines the lensing properties of a dark matter halo, is still lacking to date. To this aim, we used a Mellin integral transform formalism to derive a closed expression for the Einasto surface density and related properties in terms of the Fox H and Meijer G functions, which can be written as series expansions. This enables arbitrary-precision calculations of the surface density and the lensing properties of realistic dark matter halo models. Furthermore, we compared the Sérsic and Einasto surface mass densities and found differences between them, which implies that the lensing properties for both profiles differ.
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