84 research outputs found

    Diffuse coronae in cosmological simulations of milky way-sized galaxies

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    We investigate the properties of halo gas using three cosmological “zoom-in” simulations of realistic Milky Way-galaxy analogs with varying sub-grid physics. In all three cases, the mass of hot (T > 106 K) halo gas is ˜1% of the host's virial mass. The X-ray luminosity of two of the runs is consistent with observations of the Milky Way, while the third simulation is X-ray bright and resembles more closely a very massive, star-forming spiral. Hot halos extend to 140 kpc from the galactic center and are surrounded by a bubble of warm-hot (T={10}5-{10}6 K) gas that extends to the virial radius. Simulated halos agree well outside 20-30 kpc with the ÎČ-model of Miller & Bregman based on O vii absorption and O viii emission measurements. Warm-hot and hot gas contribute up to 80% of the total gas reservoir, and contain nearly the same amount of baryons as the stellar component. The mass of warm-hot and hot components falls into the range estimated for {L}* galaxies. With key observational constraints on the density of the Milky Way corona being satisfied, we show that concealing of the ubiquitous warm-hot baryons, along with the ejection of just 20%-30% of the diffuse gas out of the potential wells by supernova-driven outflows, can solve the “missing baryon problem.” The recovered baryon fraction within 3 virial radii is 90% of the universal value. With a characteristic density of ˜10-4 cm-3 at 50-80 kpc, diffuse coronae meet the requirement for fast and complete ram-pressure stripping of the gas reservoirs in dwarf galaxy satellites

    The Role of Complement Activating Collectins and Associated Serine Proteases in Patients With Hematological Malignancies, Receiving High-Dose Chemotherapy, and Autologous Hematopoietic Stem Cell Transplantations (Auto-HSCT)

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    We conducted a prospective study of 312 patients (194 with multiple myeloma, 118 with lymphomas) receiving high-dose conditioning chemotherapy and autologous hematopoietic stem cell transplantation (auto-HSCT). Polymorphisms of MBL2 and MASP2 genes were investigated and serial measurements of serum concentrations of mannose-binding lectin (MBL), CL-LK collectin and MASP-2 as well as activities of MBL-MASP-1 and MBL-MASP-2 complex were made. Serum samples were taken before conditioning chemotherapy, before HSCT and once weekly after (totally 4-5 samples); in minority of subjects also 1 and/or 3 months post transplantation. The results were compared with data from 267 healthy controls and analyzed in relation to clinical data to explore possible associations with cancer and with chemotherapy-induced medical complications. We found a higher frequency of MBL deficiency-associated genotypes (LXA/O or O/O) among multiple myeloma patients compared with controls. It was however not associated with hospital infections or post-HSCT recovery of leukocytes, but seemed to be associated with the most severe infections during follow-up. Paradoxically, high MBL serum levels were a risk factor for prolonged fever and some infections. The first possible association of MBL2 gene 3â€Č-untranslated region polymorphism with cancer (lymphoma) in Caucasians was noted. Heterozygosity for MASP2 gene +359 A>G mutation was relatively frequent in lymphoma patients who experienced bacteremia during hospital stay. The median concentration of CL-LK was higher in myeloma patients compared with healthy subjects. Chemotherapy induced marked increases in serum MBL and MASP-2 concentrations, prolonged for several weeks and relatively slighter decline in CL-LK level within 1 week. Conflicting findings on the influence of MBL on infections following chemotherapy of myeloma and lymphoma have been reported. Here we found no evidence for an association between MBL deficiency and infection during the short period of neutropenia following conditioning treatment before HSCT. However, we noted a possible protective effect of MBL during follow-up, and suspected that to be fully effective when able to act in combination with phagocytic cells after their recovery

    Relationship Between Nutritional Habits and Hair Calcium Levels in Young Women

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    The present study was conducted to investigate whether hair calcium levels are related to nutritional habits, selected status parameters, and life-style factors in young women. Eighty-five healthy female students neither pregnant nor lactating, using no hair dyes or permanents were recruited for the study. Food consumption data, including fortified products and dietary supplements were collected with 4-day records. The calcium levels in hair and serum were analyzed by atomic absorption spectroscopy. Serum osteocalcin and the C-terminal telopeptide of type I collagen were assayed by ELISA. The women were divided into four groups according to their total vitamin D and calcium intakes and hair calcium levels. At adequate calcium intake and comparable serum bone biomarker levels, supplemental vitamin D increased the hair calcium levels. On the other hand, at lower than estimated adequate requirement of vitamin D intake the hair calcium levels were comparable in women with low calcium intakes but consuming high amounts of meat products or those whose diets were rich in dairy products, possibly due to homeostatic mechanisms. Elevated hair calcium was seen in 25% of subjects and could not be related to nutritional or life-style factors. The results show that the hair calcium levels were weakly related to the quality of diet, with some synergistic interactions between nutrients, especially vitamin D and magnesium

    Orexins/Hypocretins Acting at Gi Protein-Coupled OX2 Receptors Inhibit Cyclic AMP Synthesis in the Primary Neuronal Cultures

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    Orexins A and B are newly discovered neuropeptides with pleiotropic activity. They signal through two G protein-coupled receptors: OX1 and OX2. In this study, we examined the expression of orexin receptors and effects of the receptors’ activation on cyclic AMP formation in the primary neuronal cell cultures from rat cerebral cortex. Both types of orexin receptors were expressed in rat cortical neurons; the level of OX2R was markedly higher compared to OX1R. Orexin A (an agonist of OX1R and OX2R) and [Ala11-D-Leu15]orexin B (a selective agonist of OX2R) did not affect basal cyclic AMP formation in the primary neuronal cell cultures. Both peptides (0.001–1 ΌM) inhibited, in a concentration-dependent manner and IC50 values in low nanomolar range, the increase in the nucleotide production evoked by forskolin (1 ΌM; a direct activator of adenylyl cyclase), pituitary adenylate cyclase-activating polypeptide (PACAP27; 0.1 ΌM), and vasoactive intestinal peptide (VIP; 3 ΌM). Effects of orexin A on forskolin-, PACAP27-, and VIP-stimulated cyclic AMP synthesis were blocked by TCS OX2 29 (a selective antagonist of OX2R), and unaffected by SB 408124 (a selective antagonist of OX1R). Pretreatment of neuronal cell cultures with pertussis toxin (PTX) abolished the inhibitory action of orexin A on forskolin- and PACAP-stimulated cyclic AMP accumulation. It is suggested that in cultured rat cortical neurons orexins, acting at OX2 receptors coupled to PTX-sensitive Gi protein, inhibit cyclic AMP synthesis

    Angular Momentum of Early- and Late-type Galaxies: Nature or Nurture?

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    We investigate the origin, the shape, the scatter, and the cosmic evolution in the observed relationship between specific angular momentum j⋆j_\star and the stellar mass M⋆M_\star in early-type (ETGs) and late-type galaxies (LTGs). Specifically, we exploit the observed star-formation efficiency and chemical abundance to infer the fraction f_\rm inf of baryons that infall toward the central regions of galaxies where star formation can occur. We find f_\rm inf\approx 1 for LTGs and ≈0.4\approx 0.4 for ETGs with an uncertainty of about 0.250.25 dex, consistent with a biased collapse. By comparing with the locally observed j⋆j_\star vs. M⋆M_\star relations for LTGs and ETGs we estimate the fraction fjf_j of the initial specific angular momentum associated to the infalling gas that is retained in the stellar component: for LTGs we find fj≈1.11+0.75−0.44f_j\approx 1.11^+0.75_-0.44, in line with the classic disc formation picture; for ETGs we infer fj≈0.64+0.20−0.16f_j\approx 0.64^+0.20_-0.16, that can be traced back to a z<1z<1 evolution via dry mergers. We also show that the observed scatter in the j⋆j_\star vs. M⋆M_\star relation for both galaxy types is mainly contributed by the intrinsic dispersion in the spin parameters of the host dark matter halo. The biased collapse plus mergers scenario implies that the specific angular momentum in the stellar components of ETG progenitors at z∌2z\sim 2 is already close to the local values, in pleasing agreement with observations. All in all, we argue such a behavior to be imprinted by nature and not nurtured substantially by the environment

    The Baryonic Collapse Efficiency of Galaxy Groups in the RESOLVE and ECO Surveys

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    We examine the z = 0 group-integrated stellar and cold baryonic (stars + cold atomic gas) mass functions (group SMF and CBMF) and the baryonic collapse efficiency (group cold baryonic to dark matter halo mass ratio) using the RESOLVE and ECO survey galaxy group catalogs and a galform semi-analytic model (SAM) mock catalog. The group SMF and CBMF fall off more steeply at high masses and rise with a shallower low-mass slope than the theoretical halo mass function (HMF). The transition occurs at group-integrated cold baryonic mass M_coldbary ~ 10^11 Msun. The SAM, however, has significantly fewer groups at the transition mass ~ 10^11 Msun and a steeper low-mass slope than the data, suggesting that feedback is too weak in low-mass halos and conversely too strong near the transition mass. Using literature prescriptions to include hot halo gas and potential unobservable galaxy gas produces a group BMF with slope similar to the HMF even below the transition mass. Its normalization is lower by a factor of ~2, in agreement with estimates of warm-hot gas making up the remaining difference. We compute baryonic collapse efficiency with the halo mass calculated two ways, via halo abundance matching (HAM) and via dynamics (extended all the way to three-galaxy groups using stacking). Using HAM, we find that baryonic collapse efficiencies reach a flat maximum for groups across the halo mass range of M_halo ~ 10^11.4-12 Msun, which we label "nascent groups." Using dynamics, however, we find greater scatter in baryonic collapse efficiencies, likely indicating variation in group hot-to-cold baryon ratios. Similarly, we see higher scatter in baryonic collapse efficiencies in the SAM when using its true groups and their group halo masses as opposed to friends-of-friends groups and HAM masses

    An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen

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    Background: Cats are the major source of indoor inhalant allergens after house dust mites. The global incidence of cat allergies is rising sharply, posing a major public health problem. Ten cat allergens have been identified. The major allergen responsible for symptoms is Fel d 1, a secretoglobin and not a lipocalin, making the cat a special case among mammals. Main body: Given its clinical predominance, it is essential to have a good knowledge of this allergenic fraction, including its basic structure, to understand the new exciting diagnostic and therapeutic applications currently in development. The recent arrival of the component-resolved diagnosis, which uses molecular allergens, represents a unique opportunity to improve our understanding of the disease. Recombinant Fel d 1 is now available for in vitro diagnosis by the anti-Fel d 1 specific IgE assay. The first part of the review will seek to describe the recent advances related to Fel d 1 in terms of positive diagnosis and assessment of disease severity. In daily practice, anti-Fel d 1 IgE tend to replace those directed against the overall extract but is this attitude justified? We will look at the most recent arguments to try to answer this question. In parallel, a second revolution is taking place thanks to molecular engineering, which has allowed the development of various forms of recombinant Fel d 1 and which seeks to modify the immunomodulatory properties of the molecule and thus the clinical history of the disease via various modalities of anti-Fel d 1-specific immunotherapy. We will endeavor to give a clear and practical overview of all these trends

    The CLIC Potential for New Physics

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    The Compact Linear Collider (CLIC) is a mature option for the future of high energy physics. It combines the benefits of the clean environment of e+e−e^+e^- colliders with operation at high centre-of-mass energies, allowing to probe scales beyond the reach of the Large Hadron Collider (LHC) for many scenarios of new physics. This places the CLIC project at a privileged spot in between the precision and energy frontiers, with capabilities that will significantly extend knowledge on both fronts at the end of the LHC era. In this report we review and revisit the potential of CLIC to search, directly and indirectly, for physics beyond the Standard Model
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