224 research outputs found

    Dusting off the diffuse interstellar bands: DIBs and dust in extragalactic SDSS spectra

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    Using over a million and a half extragalactic spectra we study the properties of the mysterious Diffuse Interstellar Bands (DIBs) in the Milky Way. These data provide us with an unprecedented sampling of the skies at high Galactic-latitude and low dust-column-density. We present our method, study the correlation of the equivalent width of 8 DIBs with dust extinction and with a few atomic species, and the distribution of four DIBs - 5780.6A, 5797.1A, 6204.3A, and 6613.6A - over nearly 15000 squared degrees. As previously found, DIBs strengths correlate with extinction and therefore inevitably with each other. However, we show that DIBs can exist even in dust free areas. Furthermore, we find that the DIBs correlation with dust varies significantly over the sky. DIB under- or over-densities, relative to the expectation from dust, are often spread over hundreds of square degrees. These patches are different for the four DIBs, showing that they are unlikely to originate from the same carrier, as previously suggested.Comment: MNRAS accepte

    Using machine learning to classify the diffuse interstellar bands

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    Using over a million and a half extragalactic spectra we study the correlations of the Diffuse Interstellar Bands (DIBs) in the Milky Way. We measure the correlation between DIB strength and dust extinction for 142 DIBs using 24 stacked spectra in the reddening range E(B-V) < 0.2, many more lines than ever studied before. Most of the DIBs do not correlate with dust extinction. However, we find 10 weak and barely studied DIBs with correlations that are higher than 0.7 with dust extinction and confirm the high correlation of additional 5 strong DIBs. Furthermore, we find a pair of DIBs, 5925.9A and 5927.5A which exhibits significant negative correlation with dust extinction, indicating that their carrier may be depleted on dust. We use Machine Learning algorithms to divide the DIBs to spectroscopic families based on 250 stacked spectra. By removing the dust dependency we study how DIBs follow their local environment. We thus obtain 6 groups of weak DIBs, 4 of which are tightly associated with C2 or CN absorption lines.Comment: minor changes, MNRAS accepte

    Toll-like Receptor-4 Regulation of Hepatic Cyp3a11 Metabolism in a Mouse Model of LPS-induced CNS Inflammation

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    Central nervous system (CNS) infection and inflammation severely reduce the capacity of cytochrome P-450 metabolism in the liver. We developed a mouse model to examine the effects of CNS inflammation on hepatic cytochrome P-450 metabolism. FVB, C57BL/6, and C3H/HeouJ mice were given Escherichia coli LPS (2.5 μg) by intracerebroventricular (ICV) injection. The CNS inflammatory response was confirmed by the elevation of TNF-α and/or IL-1β proteins in the brain. In all mouse strains, LPS produced a 60–70% loss in hepatic Cyp3a11 expression and activity compared with saline-injected controls. Adrenalectomy did not prevent the loss in Cyp3a11 expression or activity, thereby precluding the involvement of the hypothalamic-adrenal-pituitary axis. Endotoxin was detectable (1–10 ng/ml) in serum between 15 and 120 min after ICV dosing of 2.5 μg LPS. Peripheral administration of 2.5 μg LPS by intraperitoneal injection produced similar serum endotoxin levels and a similar loss (60%) in Cyp3a11 expression and activity in the liver. The loss of Cyp3a11 in response to centrally or peripherally administered LPS could not be evoked in Toll-like receptor-4 (TLR4)-mutant (C3H/ HeJ) mice, indicating that TLR4 signaling pathways are directly involved in the enzyme loss. In summary, we conclude that LPS is transferred from the brain to the circulation in significant quantities in a model of CNS infection or inflammation. Subsequently, LPS that has reached the circulation stimulates a TLR4-dependent mechanism in the periphery, evoking a reduction in Cyp3a11 expression and metabolism in the liver

    Prevalence of Toxoplasmosis Infection in Iraqi Women with Different Types of Cancer

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    Background: Toxoplasma gondii is an obligatory intracellular parasite that is consider a major invasive parasite in immunocompromised individuals. Objective: To determined the prevalence of Toxoplasmosis in patients with different types of cancer in Iraq. Patients and Methods: Samples of blood were gathered from 258 women who included 112 healthy controls samples and 146 samples with different types of cancer. They were attended Oncology Teaching Hospital in the Medical City Hospital in Baghdad province from October, 2016 to February, 2017. Then the sera were tested to determine the anti- T. gondii antibodies (IgG and IgM) using enzyme linked immunosorbent assay. Results: The highest seropositive rate of T. gondii IgG were noted in patients with lymph node cancer followed by breast, colorectal, liver, pancreas, lung, ovary, prostate cancer which was (100%, 77.50%, 77.42%, 75.00%, 66.67%, 66.67%, 54.55%, 28.57%) respectively with significant differences (P<0.01). This study focused on breast and colorectal cancer. According to the age groups, the seroprevalence of anti- T. gondii IgG was the highest in the age group (26-35) years in patients with colorectal and breast cancer which was (378.309 IU/ml, 374.561 IU/ml respectively) compared with control group (148.917 IU/ml). In regard to the anti- tumor dosage, the highest mean titer of IgG observed in dosage (0), the mean titer of IgG in patients with colorectal and breast cancer whose were seropositive to anti-T. gondii IgG were (242.016 IU/ml and 227.275 IU/ml) respectively, while in seronegative patients to anti-T. gondii IgG  were (8.594 IU/ml and 6.011 IU/ml) respectively. Conclusion: These finding suggest that incidental rate of toxoplasmosis is higher in cancer patients. Thus, the incidental rate of toxoplasmosis could be considered as an indication to the high risk of cancer. In addition, anti- T. gondii IgG test has to be taken into consideration as markers for staging cancer disease

    Direct evidence of AGN feedback: a post-starburst galaxy stripped of its gas by AGN-driven winds

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    Post-starburst E+A galaxies show indications of a powerful starburst that was quenched abruptly. Their disturbed, bulge-dominated morphologies suggest that they are merger remnants. The more massive E+A galaxies are suggested to be quenched by active galactic nucleus (AGN) feedback, yet little is known about AGN-driven winds in this short-lived phase. We present spatially resolved integral field unit spectroscopy by the Keck Cosmic Web Imager of SDSS J003443.68 + 251020.9, at z = 0.118. The system consists of two galaxies, the larger of which is a post-starburst E+A galaxy hosting an AGN. Our modelling suggests a 400 Myr starburst, with a peak star formation rate of 120 M⊙ yr^(−1). The observations reveal stationary and outflowing gas, photoionized by the central AGN. We detect gas outflows to a distance of 17 kpc from the central galaxy, far beyond the region of the stars (∼3 kpc), inside a conic structure with an opening angle of 70 deg. We construct self-consistent photoionization and dynamical models for the different gas components and show that the gas outside the galaxy forms a continuous flow, with a mass outflow rate of about 24 M⊙ yr^(−1). The gas mass in the flow, roughly 10^9M⊙⁠, is larger than the total gas mass within the galaxy, some of which is outflowing too. The continuity of the flow puts a lower limit of 60 Myr on the duration of the AGN feedback. Such AGNs are capable of removing, in a single episode, most of the gas from their host galaxies and expelling enriched material into the surrounding circumgalactic medium

    Dual-specificity phosphatase 1 and tristetraprolin cooperate to regulate macrophage responses to lipopolysaccharide

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    Dual-specificity phosphatase (DUSP) 1 dephosphorylates and inactivates members of the MAPK superfamily, in particular, JNKs, p38a, and p38b MAPKs. It functions as an essential negative regulator of innate immune responses, hence disruption of the Dusp1 gene renders mice extremely sensitive to a wide variety of experimental inflammatory challenges. The principal mechanisms behind the overexpression of inflammatory mediators by Dusp12/2 cells are not known. In this study, we use a genetic approach to identify an important mechanism of action of DUSP1, involving the modulation of the activity of the mRNA-destabilizing protein tristetraprolin. This mechanism is key to the control of essential early mediators of inflammation, TNF, CXCL1, and CXCL2, as well as the anti-inflammatory cytokine IL-10. The same mechanism also contributes to the regulation of a large number of transcripts induced by treatment of macrophages with LPS. These findings demonstrate that modulation of the phosphorylation status of tristetraprolin is an important physiological mechanism by which innate immune responses can be controlled

    Beta interferon production is regulated by P38 mitogen-activated protein kinase in macrophages via both MSK1/2-and tristetraprolin-dependent pathways

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    Autocrine or paracrine signaling by beta interferon (IFN-β) is essential for many of the responses of macrophages to pathogen-associated molecular patterns. This feedback loop contributes to pathological responses to infectious agents and is therefore tightly regulated. We demonstrate here that macrophage expression of IFN-β is negatively regulated by mitogen- and stress-activated kinases 1 and 2 (MSK1/2). Lipopolysaccharide (LPS)-induced expression of IFN-β was elevated in both MSK1/2 knockout mice and macrophages. Although MSK1 and -2 promote the expression of the anti-inflammatory cytokine interleukin 10, it did not strongly contribute to the ability of MSKs to regulate IFN-β expression. Instead, MSK1 and -2 inhibit IFN-β expression via the induction of dual-specificity phosphatase 1 (DUSP1), which dephosphorylates and inactivates the mitogen-activated protein kinases p38 and Jun N-terminal protein kinase (JNK). Prolonged LPS-induced activation of p38 and JNK, phosphorylation of downstream transcription factors, and overexpression of IFN-β mRNA and protein were similar in MSK1/2 and DUSP1 knockout macrophages. Two distinct mechanisms were implicated in the overexpression of IFN-β: first, JNKmediated activation of c-jun, which binds to the IFN-β promoter, and second, p38-mediated inactivation of the mRNA-destabilizing factor tristetraprolin, which we show is able to target the IFN-β mRNA

    PET Imaging of Extracellular pH in Tumors with \u3csup\u3e64\u3c/sup\u3eCu- and \u3csup\u3e18\u3c/sup\u3eF-Labeled pHLIP Peptides: A Structure–Activity Optimization Study

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    pH (low) insertion peptides (pHLIP peptides) target acidic extracellular environments in vivo due to pH-dependent cellular membrane insertion. Two variants (Var3 and Var7) and wild-type (WT) pHLIP peptides have shown promise for in vivo imaging of breast cancer. Two positron emitting radionuclides (64Cu and 18F) were used to label the NOTA- and NO2A-derivatized Var3, Var7, and WT peptides for in vivo biodistribution studies in 4T1 orthotopic tumor-bearing BALB/c mice. All of the constructs were radiolabeled with 64Cu or [18F]-AlF in good yield. The in vivo biodistribution of the 12 constructs in 4T1 orthotopic allografted female BALB/c mice indicated that NO2A-cysVar3, radiolabeled with either 18F (4T1 uptake; 8.9 ± 1.7%ID/g at 4 h p.i.) or 64Cu (4T1 uptake; 8.2 ± 0.9%ID/g at 4 h p.i. and 19.2 ± 1.8% ID/g at 24 h p.i.), shows the most promise for clinical translation. Additional studies to investigate other tumor models (melanoma, prostate, and brain tumor models) indicated the universality of tumor targeting of these tracers. From this study, future clinical translation will focus on 18F- or 64Cu-labeled NO2A-cysVar3

    Exploring the Diversity of Type 1 Active Galactic Nuclei Identified in SDSS-IV/SPIDERS

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    We present a statistical analysis of the optical properties of an X-ray selected Type 1 AGN sample, using high signal to-noise ratio (S/N>20S/N>20) spectra of the counterparts of the ROSAT/2RXS sources in the footprint of the SDSS-IV/SPIDERS (Spectroscopic IDentification of eROSITA Sources) programme. The final sample contains 2100 sources. It significantly extends the redshift and luminosity ranges (z0.010.80\rm z \sim 0.01 - 0.80 and L0.12.4keV\rm L_{0.1-2.4 \,keV} ~ 2.0×1041\rm 2.0 \times 10^{41} - 1.0×1046ergs1\rm 1.0 \times 10^{46} \, erg s^{-1} ) used so far in this kind of analysis. By means of a Principal Component Analysis, we derive Eigenvector (EV) 1 and 2 in an eleven dimensional optical and X-ray parameter space, which are consistent with previous results. The validity of the correlations of the Eddington ratio L/LEdd\rm L/L_{Edd} with EV1 and the black hole mass with EV2 are strongly confirmed These results imply that L/LEdd\rm L/L_{Edd} and black hole mass are related to the diversity of the optical properties of Type 1 AGN. Investigating the relation of the width and asymmetry of Hβ\rm H\beta and the relative strength of the iron emission rFeII\rm r_{FeII} , we show that our analysis supports the presence of a distinct kinematic region: the Very Broad Line Region. Furthermore, comparing sources with a red-asymmetric broad Hβ\rm H\beta emission line to sources for which it is blue-asymmetric, we find an intriguing difference in the correlation of the FeII and the continuum emission strengths. We show that this contrasting behaviour is consistent with a flattened, stratified model of the Broad Line Region, in which the FeII emitting region is shielded from the central source.Comment: Resubmitted, after taking into account the referee's comments. The catalogue by Coffey et al. (2019), can be found at https://www.sdss.org/dr14/data_access/value-added-catalogs
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