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Cosmic evolution of stellar quenching by AGN feedback: clues from the Horizon-AGN simulation
Beckmann, R. S.,Devriendt, J.,Slyz, A.,Peirani, S.,Richardson, M. L. A.,Dubois, Y.,Pichon, C.,Chisari, N. E.,Kaviraj, S.,Laigle, C.,Volonteri, M. Oxford University Press 2017 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.472 No.1
<P>The observed massive end of the galaxy stellar mass function is steeper than its predicted dark matter halo counterpart in the standard Lambda cold dark matter paradigm. In this paper, we investigate the impact of active galactic nuclei (AGN) feedback on star formation in massive galaxies. We isolate the impact of AGN by comparing two simulations from the HORIZON suite, which are identical except that one also includes supermassive black holes (SMBHs) and related feedback models. This allows us to cross-identify individual galaxies between simulations and quantify the effect of AGN feedback on their properties, including stellar mass and gas outflows. We find that massive galaxies (M-* >= 10(11) M-circle dot) are quenched by AGN feedback to the extent that their stellar masses decrease by up to 80 per cent at z = 0. SMBHs affect their host halo through a combination of outflows that reduce their baryonic mass, particularly for galaxies in the mass range 10(9) M-circle dot <= M-* <= 10(11) M-circle dot, and a disruption of central gas inflows, which limits in situ star formation. As a result, net gas inflows on to massive galaxies, M-* >= 10(11) M-circle dot, drop by up to 70 per cent. We measure a redshift evolution in the stellar mass ratio of twin galaxies with and without AGN feedback, with galaxies of a given stellar mass showing stronger signs of quenching earlier on. This evolution is driven by a progressive flattening of the M-SMBH-M-* relation with redshift, particularly for galaxies with M-* <= 10(10) M-circle dot. M-SMBH/M-* ratios decrease over time, as falling average gas densities in galaxies curb SMBH growth.</P>
Electronic properties of intrinsically conducting polymer-cellulose based composites
M.J. Richardson,J.H. Johnston,T. Borrmann 한국물리학회 2006 Current Applied Physics Vol.6 No.3
In situ polymerisation of pyrrole, aniline and derivatives with cellulosic substrates provides composites with potentially useful properties. Conductivity relative to the untreated substrate is increased, and an inverse relationship of conductivity to dielectric, and hence capacitance is observed. A metallic layer such as copper may be deposited electrochemically onto the surface of the composite, and the metal surface may then be oxidised to form either the green carbonate patina commonly seen on bronze statues, or a deep red oxide layer. When the polymer used is polypyrrole, silver may be reduced onto the surface following reduction of the polymer via hydrazine or sodium borohydride. The composites have been characterised via scanning electron microscopy, impedance analysis, cyclic voltammetry and conductivity measurements.
Sharon M. Nickols-Richardson,Kathryn E. Piehowski,Catherine J. Metzgar,Debra L. Miller,Amy G. Preston 한국영양학회 2014 Nutrition Research and Practice Vol.8 No.6
BACKGROUND/OBJECTIVES: The type of sweet snack incorporated into an energy-restricted diet (ERD) may produce differential effects on metabolic improvements associated with body weight (BW) loss. This study compared effects of incorporating either twice daily energy-controlled dark chocolate snacks plus once daily sugar-free cocoa beverage (DC) to non-chocolate snacks plus sugar-free non-cocoa beverage (NC) into an ERD on BW loss and metabolic outcomes. MATERIALS/METHODS: In an 18-week randomized comparative trial, 60 overweight/obese premenopausal women were assigned to DC (n = 30) or NC group (n = 30). Dietary intake was measured at baseline and week 18, and BW, anthropometrics, blood pressure (BP) and serum glucose, insulin and lipid concentrations were measured at baseline, and weeks 6, 12 and 18. Data were analyzed using repeated measures ANOVA. RESULTS: Using intention-to-treat analysis, women in DC and NC groups reduced energy intake (both P < 0.001) and lost 4.4 ± 0.6 kg and 5.0 ± 0.9 kg (both P < 0.001), respectively. Both groups lowered systolic and diastolic BP [DC = 2.7 (P < 0.05), 2.7 (P < 0.01); NC = 3.4 (P < 0.01), 4.2 (P < 0.01) mmHg, respectively]. Glucose and insulin concentrations decreased by 0.72 mmol/L (P < 0.001) and 13.20 pmol/L (P < 0.01) in DC group and by 0.83 mmol/L (P < 0.001) and 13.20 pmol/L (P < 0.01), respectively, in NC group. Total cholesterol increased in NC group (P < 0.05), with no significant lipid changes in DC group. There were no significant differences in biomarker outcomes between groups. CONCLUSIONS: Overweight/obese premenopausal women following an 18-week ERD that included either DC or NC sweet snack and sugar-free beverage lost equivalent amounts of BW and improved BP measurements and glucose and insulin concentrations.
Physico-chemical confinement of helical nanofilaments
Lee, S.,Kim, H.,Shin, T. J.,Tsai, E.,Richardson, J. M.,Korblova, E.,Walba, D. M.,Clark, N. A.,Lee, S. B.,Yoon, D. K. The Royal Society of Chemistry 2015 SOFT MATTER Vol.11 No.18
<P>Helical nanofilaments (HNFs) have attracted much interest because of their unique optical properties, but there have been many hurdles to overcome in using them for the practical applications due to their structural complexity. Here we demonstrate that the molecular configuration and layer conformation of a modulated HNF (HNFs<SUB>(mod)</SUB>) can be studied using a physicochemical confinement system. The layer directions affected by the chemical affinity between the mesogen and surface were drastically controlled in surface-modified nanochannels. Furthermore, an <I>in situ</I> experiment using grazing-incidence X-ray diffraction (GIXD) was carried out to investigate in detail the structural evolution through thermal transitions. The results demonstrate that the HNF<SUB>(mod)</SUB> structure can be perfectly controlled for functional HNF device applications, and a combined system with chemical and physical confinement effects will be helpful to better understand the fundamentals of soft matter.</P> <P>Graphic Abstract</P><P>Helical nanofilaments (HNFs) have attracted much interest because of their unique optical properties, but there have been many hurdles to overcome in using them for the practical applications due to their structural complexity. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5sm00417a'> </P>
<i>ITGB6</i> loss-of-function mutations cause autosomal recessive amelogenesis imperfecta
Wang, Shih-Kai,Choi, Murim,Richardson, Amelia S.,Reid, Bryan M.,Lin, Brent P.,Wang, Susan J.,Kim, Jung-Wook,Simmer, James P.,Hu, Jan C.-C. Oxford University Press 2014 Human Molecular Genetics Vol.23 No.8
<P>Integrins are cell-surface adhesion receptors that bind to extracellular matrices (ECM) and mediate cell–ECM interactions. Some integrins are known to play critical roles in dental enamel formation. We recruited two Hispanic families with generalized hypoplastic amelogenesis imperfecta (AI). Analysis of whole-exome sequences identified three <I>integrin beta 6</I> (<I>ITGB6</I>) mutations responsible for their enamel malformations. The female proband of Family 1 was a compound heterozygote with an <I>ITGB6</I> transition mutation in Exon 4 (g.4545G > A c.427G > A p.Ala143Thr) and an <I>ITGB6</I> transversion mutation in Exon 6 (g.27415T > A c.825T > A p.His275Gln). The male proband of Family 2 was homozygous for an <I>ITGB6</I> transition mutation in Exon 11 (g.73664C > T c.1846C > T p.Arg616*) and hemizygous for a transition mutation in Exon 6 of <I>Nance–Horan Syndrome</I> (<I>NHS</I> Xp22.13; g.355444T > C c.1697T > C p.Met566Thr). These are the first disease-causing <I>ITGB6</I> mutations to be reported. Immunohistochemistry of mouse mandibular incisors localized ITGB6 to the distal membrane of differentiating ameloblasts and pre-ameloblasts, and then ITGB6 appeared to be internalized by secretory stage ameloblasts. ITGB6 expression was strongest in the maturation stage and its localization was associated with ameloblast modulation. Our findings demonstrate that early and late amelogenesis depend upon cell–matrix interactions. Our approach (from knockout mouse phenotype to human disease) demonstrates the power of mouse reverse genetics in mutational analysis of human genetic disorders and attests to the need for a careful dental phenotyping in large-scale knockout mouse projects.</P>