The effects of star formation on the low-metallicity ISM: NGC4214 mapped with Herschel/PACS spectroscopy

We present Herschel/PACS spectroscopic maps of the dwarf galaxy NC4214 observed in 6 far infrared fine-structure lines: [C II] 158mu, [O III] 88mu, [O I] 63mu, [O I] 146mu, [N II] 122mu, and [N II] 205mu. The maps are sampled to the full telescope spatial resolution and reveal unprecedented detail on ~ 150 pc size scales. We detect [C II] emission over the whole mapped area, [O III] being the most luminous FIR line. The ratio of [O III]/[C II] peaks at about 2 toward the sites of massive star formation, higher than ratios seen in dusty starburst galaxies. The [C II]/CO ratios are 20 000 to 70 000 toward the 2 massive clusters, which are at least an order of magnitude larger than spiral or dusty starbursts, and cannot be reconciled with single-slab PDR models. Toward the 2 massive star-forming regions, we find that L[CII] is 0.5 to 0.8% of the LTIR . All of the lines together contribute up to 2% of LTIR . These extreme findings are a consequence of the lower metallicity and young, massive-star formation commonly found in dwarf galaxies. These conditions promote large-scale photodissociation into the molecular reservoir, which is evident in the FIR line ratios. This illustrates the necessity to move to multiphase models applicable to star-forming clusters or galaxies as a whole.Comment: Accepted for publication in the A&A Herschel Special Issu

Pentosan polysulfate inhibits atherosclerosis in watanabe heritable hyperlipidemic rabbits; differential modulation of metalloproteinase-2 and -9

Pentosan polysulfate (PPS), a heparinoid compound essentially devoid of anticoagulant activity, modulates cell growth and decreases inflammation. We investigated the effect of PPS on the progression of established atherosclerosis in Watanabe heritable hyperlipidemic (WHHL) rabbits. After severe atherosclerosis developed on an atherogenic diet, WHHL rabbits were treated with oral PPS or tap water for 1 month. The aortic intima-to-media ratio and macrophage infiltration were reduced, plaque collagen content was increased, and plaque fibrous caps were preserved by PPS treatment. Plasma lipid levels and post-heparin hepatic lipase activity remained unchanged. However, net collagenolytic activity in aortic extracts was decreased, and the levels of matrix metalloproteinase (MMP)-2 and tissue inhibitor of metalloproteinase (TIMP) activity were increased by PPS. Moreover, PPS treatment decreased tumor necrosis factor α (TNFα)-stimulated proinflammatory responses, in particular activation of nuclear factor-κB and p38, and activation of MMPs in macrophages. In conclusion, oral PPS treatment prevents progression of established atherosclerosis in WHHL rabbits. This effect may be partially mediated by increased MMP-2 and TIMP activities in the aortic wall and reduced TNFα-stimulated inflammation and MMP activation in macrophages. Thus, PPS may be a useful agent in inhibiting the progression of atherosclerosis

Gas-to-Dust mass ratios in local galaxies over a 2 dex metallicity range

This paper analyses the behaviour of the gas-to-dust mass ratio (G/D) of local Universe galaxies over a large metallicity range. We combine three samples: the Dwarf Galaxy Survey, the KINGFISH survey and a subsample from Galametz et al. (2011) totalling 126 galaxies, covering a 2 dex metallicity range, with 30% of the sample with 12+log(O/H) < 8.0. The dust masses are homogeneously determined with a semi-empirical dust model, including submm constraints. The atomic and molecular gas masses are compiled from the literature. Two XCO are used to estimate molecular gas masses: the Galactic XCO, and a XCO depending on the metallicity (as Z^{-2}). Correlations with morphological types, stellar masses, star formation rates and specific star formation rates are discussed. The trend between G/D and metallicity is empirically modelled using power-laws (slope of -1 and free) and a broken power-law. We compare the evolution of the G/D with predictions from chemical evolution models. We find that out of the five tested galactic parameters, metallicity is the galactic property driving the observed G/D. The G/D versus metallicity relation cannot be represented by a power-law with a slope of -1 over the whole metallicity range. The observed trend is steeper for metallicities lower than ~ 8.0. A large scatter is observed in the G/D for a given metallicity, with a dispersion of 0.37 dex in metallicity bins of ~0.1 dex. The broken power-law reproduces best the observed G/D and provides estimates of the G/D that are accurate to a factor of 1.6. The good agreement of the G/D and its scatter with the three tested chemical evolution models shows that the scatter is intrinsic to galactic properties, reflecting the different star formation histories, dust destruction efficiencies, dust grain size distributions and chemical compositions across the sample. (abriged)Comment: 23 pages, 12 figures, accepted in Astronomy & Astrophysic

Linking dust emission to fundamental properties in galaxies: The low-metallicity picture

In this work, we aim at providing a consistent analysis of the dust properties from metal-poor to metal-rich environments by linking them to fundamental galactic parameters. We consider two samples of galaxies: the Dwarf Galaxy Survey (DGS) and KINGFISH, totalling 109 galaxies, spanning almost 2 dex in metallicity. We collect infrared (IR) to submillimetre (submm) data for both samples and present the complete data set for the DGS sample. We model the observed spectral energy distributions (SED) with a physically-motivated dust model to access the dust properties. Using a different SED model (modified blackbody), dust composition (amorphous carbon), or wavelength coverage at submm wavelengths results in differences in the dust mass estimate of a factor two to three, showing that this parameter is subject to non-negligible systematic modelling uncertainties. For eight galaxies in our sample, we find a rather small excess at 500 microns (< 1.5 sigma). We find that the dust SED of low-metallicity galaxies is broader and peaks at shorter wavelengths compared to more metal-rich systems, a sign of a clumpier medium in dwarf galaxies. The PAH mass fraction and the dust temperature distribution are found to be driven mostly by the specific star-formation rate, SSFR, with secondary effects from metallicity. The correlations between metallicity and dust mass or total-IR luminosity are direct consequences of the stellar mass-metallicity relation. The dust-to-stellar mass ratios of metal-rich sources follow the well-studied trend of decreasing ratio for decreasing SSFR. The relation is more complex for highly star-forming low-metallicity galaxies and depends on the chemical evolutionary stage of the source (i.e., gas-to-dust mass ratio). Dust growth processes in the ISM play a key role in the dust mass build-up with respect to the stellar content at high SSFR and low metallicity. (abridged)Comment: 44 pages (20 pages main body plus 5 Appendices), 11 figures, 9 tables, accepted for publication in A&

Chemical composition and temperature influence on the rheological behaviour of honeys

The purpose of this work was to examine the viscoelastic properties of Spanish honeys with various sugar contents [fructose (32 42 g/100 g honey), glucose (24 35 g/100 g honey), sucrose (0.0 3.4 g/100 g honey)]; concentrations (79 83 &#9702;Brix), and moisture levels (16 19 g/100 g honey) at different temperatures (5, 10, 15, 20, 25, 30, and 40&#9702;C). Honey showed Newtonian behaviour, presenting a highly viscous part (loss modulus was much greater than the elastic modulus). The loss modulus (G ) and viscosity increased with moisture content and a decrease with temperature. Exponential and power law models were applied to fit loss modulus and viscosity data. Polynomial models were proposed to describe the combined effect of temperature, fructose, glucose, sucrose content, other sugars, non-sugar substance, and moisture content.Oroian, MA.; Amariei, S.; Escriche Roberto, MI.; Leahu, A.; Damian, C.; Gutt, G. (2014). Chemical composition and temperature influence on the rheological behaviour of honeys. International Journal of Food Properties. 17(10):2228-2240. doi:10.1080/10942912.2013.791835S222822401710Kaya, A., Ko, S., & Gunasekaran, S. (2008). Viscosity and Color Change During In Situ Solidification of Grape Pekmez. Food and Bioprocess Technology, 4(2), 241-246. doi:10.1007/s11947-008-0169-4Bhandari, B., D’Arcy, B., & Chow, S. (1999). Rheology of selected Australian honeys. Journal of Food Engineering, 41(1), 65-68. doi:10.1016/s0260-8774(99)00078-3CHEN, Y.-W., LIN, C.-H., WU, F.-Y., & CHEN, H.-H. (2009). RHEOLOGICAL PROPERTIES OF CRYSTALLIZED HONEY PREPARED BY A NEW TYPE OF NUCLEI. Journal of Food Process Engineering, 32(4), 512-527. doi:10.1111/j.1745-4530.2007.00227.xYanniotis, S., Skaltsi, S., & Karaburnioti, S. (2006). Effect of moisture content on the viscosity of honey at different temperatures. Journal of Food Engineering, 72(4), 372-377. doi:10.1016/j.jfoodeng.2004.12.017Saravana Kumar, J., & Mandal, M. (2009). Rheology and thermal properties of marketed Indian honey. Nutrition & Food Science, 39(2), 111-117. doi:10.1108/00346650910943217Oroian, M., Amariei, S., Escriche, I., & Gutt, G. (2011). Rheological Aspects of Spanish Honeys. Food and Bioprocess Technology, 6(1), 228-241. doi:10.1007/s11947-011-0730-4Oroian, M. (2012). Physicochemical and Rheological Properties of Romanian Honeys. Food Biophysics, 7(4), 296-307. doi:10.1007/s11483-012-9268-xCohen, I., & Weihs, D. (2010). Rheology and microrheology of natural and reduced-calorie Israeli honeys as a model for high-viscosity Newtonian liquids. Journal of Food Engineering, 100(2), 366-371. doi:10.1016/j.jfoodeng.2010.04.023Witczak, M., Juszczak, L., & Gałkowska, D. (2011). Non-Newtonian behaviour of heather honey. Journal of Food Engineering, 104(4), 532-537. doi:10.1016/j.jfoodeng.2011.01.013Gómez-Díaz, D., Navaza, J. M., & Quintáns-Riveiro, L. C. (2005). Rheological behaviour of Galician honeys. European Food Research and Technology, 222(3-4), 439-442. doi:10.1007/s00217-005-0120-0Gómez-Díaz, D., Navaza, J. M., & Quintáns-Riveiro, L. C. (2012). Physicochemical characterization of Galician Honeys. International Journal of Food Properties, 15(2), 292-300. doi:10.1080/10942912.2010.483616Mora-Escobedo, R., Moguel-Ordóñez, Y., Jaramillo-Flores, M. E., & Gutiérrez-López, G. F. (2006). The Composition, Rheological and Thermal Properties of Tajonal (Viguiera Dentata) Mexican Honey. International Journal of Food Properties, 9(2), 299-316. doi:10.1080/10942910600596159Bhandari, B., D’Arcy, B., & Kelly, C. (1999). Rheology and crystallization kinetics of honey: Present status. International Journal of Food Properties, 2(3), 217-226. doi:10.1080/10942919909524606Mossel, B., Bhandari, B., D’Arcy, B., & Caffin, N. (2003). Determination of Viscosity of Some Australian Honeys Based on Composition. International Journal of Food Properties, 6(1), 87-97. doi:10.1081/jfp-120016626Zaitoun, S., Ghzawi, A. A.-M., Al-Malah, K. I. M., & Abu-Jdayil, B. (2001). RHEOLOGICAL PROPERTIES OF SELECTED LIGHT COLORED JORDANIAN HONEY. International Journal of Food Properties, 4(1), 139-148. doi:10.1081/jfp-100002192Yoo, B. (2004). Effect of temperature on dynamic rheology of Korean honeys. Journal of Food Engineering, 65(3), 459-463. doi:10.1016/j.jfoodeng.2004.02.006Abu-Jdayil, B., Al-Majeed Ghzawi, A., Al-Malah, K. I. ., & Zaitoun, S. (2002). Heat effect on rheology of light- and dark-colored honey. Journal of Food Engineering, 51(1), 33-38. doi:10.1016/s0260-8774(01)00034-6Mossel, B., Bhandari, B., D’Arcy, B., & Caffin, N. (2000). Use of an Arrhenius Model to Predict Rheological Behaviour in some Australian Honeys. LWT - Food Science and Technology, 33(8), 545-552. doi:10.1006/fstl.2000.0714Küçük, M., Kolaylı, S., Karaoğlu, Ş., Ulusoy, E., Baltacı, C., & Candan, F. (2007). Biological activities and chemical composition of three honeys of different types from Anatolia. Food Chemistry, 100(2), 526-534. doi:10.1016/j.foodchem.2005.10.010Giner, J., Ibarz, A., Garza, S., & Xhian-Quan, S. (1996). Rheology of clarified cherry juices. Journal of Food Engineering, 30(1-2), 147-154. doi:10.1016/s0260-8774(96)00015-5Ibarz, A., Pagán, J., & Miguelsanz, R. (1992). Rheology of clarified fruit juices. II: Blackcurrant juices. Journal of Food Engineering, 15(1), 63-73. doi:10.1016/0260-8774(92)90040-

Effect of the Monocyte Chemoattractant Protein-1/CC Chemokine Receptor 2 System on Nephrin Expression in Streptozotocin-Treated Mice and Human Cultured Podocytes

OBJECTIVE-Monocyte chemoattractant protein-1 (MCP-1), a chemokine binding to the CC chemokine receptor 2 (CCR2) and promoting monocyte infiltration, has been implicated in the pathogenesis of diabetic nephropathy. To assess the potential relevance of the MCP-1/CCR2 system in the pathogenesis of diabetic proteinuria, we studied in vitro if MCP-1 binding to the CCR2 receptor modulates nephrin expression in cultured podocytes. Moreover, we investigated in vivo if glomerular CCR2 expression is altered in kidney biopsies from patients with diabetic nephropathy and whether lack of MCP-1 affects proteinuria and expression of nephrin in experimental diabetes. RESEARCH DESIGN AND METHODS-Expression of nephrin was assessed in human podocytes exposed to rh-MCP-1 by immunofluorescence and real-time PCR. Glomerular CCR2 expression was studied in 10 kidney sections from patients with overt nephropathy and eight control subjects by immunohistochemistry. Both wild-type and MCP-1 knockout mice were made diabetic with streptozotocin. Ten weeks after the onset of diabetes, albuminuria and expression of nephrin, synaptopodin, and zonula occludens-1 were examined by immunofluorescence and immunoblotting. RESULTS-In human podocytes, MCP-1 binding to the CCR2 receptor induced a significant reduction in nephrin both mRNA and protein expression via a Rho-dependent mechanism. The MCP-1 receptor, CCR2, was overexpressed in the glomerular podocytes of patients with overt nephropathy. In experimental diabetes, MCP-1 was overexpressed within the glomeruli and the absence of MCP-1 reduced both albuminuria and downregulation of nephrin and synaptopodin. CONCLUSIONS-These findings suggest that the MCP-1/CCR2 system may be relevant in the pathogenesis of proteinuria in diabetes

Biopolymer-based structuring of liquid oil into soft solids and oleogels using water-continuous emulsions as templates

Physical trapping of a hydrophobic liquid oil in a matrix of water-soluble biopolymers was achieved using a facile two-step process by first formulating a surfactant-free oil-in-water emulsion stabilized by biopolymers (a protein and a polysaccharide) followed by complete removal of the water phase (by either high- or low-temperature drying of the emulsion) resulting in structured solid systems containing a high concentration of liquid oil (above 97 wt %). The microstructure of these systems was revealed by confocal and cryo-scanning electron microscopy, and the effect of biopolymer concentrations on the consistency of emulsions as well as the dried product was evaluated using a combination of small-amplitude oscillatory shear rheometry and large deformation fracture studies. The oleogel prepared by shearing the dried product showed a high gel strength as well as a certain degree of thixotropic recovery even at high temperatures. Moreover, the reversibility of the process was demonstrated by shearing the dried product in the presence of water to obtain reconstituted emulsions with rheological properties comparable to those of the fresh emulsion