Ample Pairs

We show that the ample degree of a stable theory with trivial forking is preserved when we consider the corresponding theory of belles paires, if it exists. This result also applies to the theory of $H$-structures of a trivial theory of rank $1$.Comment: Research partially supported by the program MTM2014-59178-P. The second author conducted research with support of the programme ANR-13-BS01-0006 Valcomo. The third author would like to thank the European Research Council grant 33882

Terminal differentiation of intestinal goblet cells is affected in <i>agr2</i> morphants.

<p>Significant increases in immature Alcian blue-stained goblet cell numbers were detected in 104- (C, <i>n</i> = 46) and 120-hpf (G, <i>n</i> = 23) <i>agr2</i> morphants compared to those in either 104- (A, <i>n</i> = 40) and 120-hpf (E, <i>n</i> = 30) wild type or in 104- (B, <i>n</i> = 41) and 120-hpf (F, <i>n</i> = 27) agr2–5 mmMO1 and 5 mmMO2-coinjected embryos. Inset shows a mature and an immature goblet cell. Comparison of both immature and mature goblet cell numbers among <i>agr2</i> morphants, wild type or agr2–5 mmMO1 and 5 mmMO2-coinjected embryos at 104 and 120 hpf are shown (D, H). A Student's <i>t</i>-test was conducted to compare immature goblet cell numbers in <i>agr2</i> morphants with those in wild type or agr2–5 mmMO1 and 5 mmMO2-coinjected embryos. *p<0.001. Scale bars represent 100 µm.</p

Transmission electron microscopy shows abnormal goblet cell structures in <i>agr2</i> morphants.

<p>Mid-intestinal images of 104- and 120-hpf wild type (A, D), agr2–5 mmMO1 and 5 mmMO2-coinjected (B, E), and <i>agr2</i> morphants (C, F) are shown. ER ultrastructure at higher magnification is shown in insets. Arrows indicate mature goblet cells and arrowheads denote immature goblet cells. Scale bars represent 2 µm.</p

Intestinal cell proliferation is not altered in <i>agr2</i> morphants.

<p>Images of p-Histone H3-stained cells in the mid-intestines and posterior intestines of 104-hpf wild type embryos (A), agr2–5 mmMO1 and 5 mmMO2-coinjected embryos (B) and <i>agr2</i> morphants (C) are shown. Arrows indicate p-Histone H3-stained cells. (D) Comparison of the percentages of p-Histone H3-stained M phase cells among wild type embryos, agr2–5 mmMO1 and 5 mmMO2-coinjected embryos, and <i>agr2</i> morphants is shown. Error bars indicate the standard error. Scale bars represent 100 µm.</p

Enlarged areas of mature Alcian-blue stained goblet cells are detected in <i>agr2</i>-overexpressed embryos.

<p>Substantially increased areas of mature Alcian blue-stained intestinal goblet cells in 42% 104-hpf <i>agr2</i>-overexpressed (C, <i>n</i> = 29) embryos compared to <i>lacZ</i>-overexpressed (B, <i>n</i> = 20) embryos and wild type (A, <i>n</i> = 18) embryos were observed. Comparison of the area of Alcian blue-stained goblet cells in wild type, <i>agr2</i>- and <i>lacZ</i>-overexpressed embryos is shown (D). Arrows indicate examples of Alcian-blue stained goblet cells with enlarged areas. Student's <i>t</i>-test was conducted and *p<0.001. Scale bars represent 100 µm.</p

Zebrafish <i>agr2</i> is solely expressed in intestinal goblet cells.

<p>Fluorescent whole-mount double <i>in situ</i> hybridization was conducted on 104-hours post fertilization (hpf) embryos using <i>agr2</i> (green) and <i>glucagon</i> (red) as RNA probes. Confocal images were recorded using excitation/emission wavelengths of 494/517 nm for fluorescein (A) and 550/570 nm for cyanine 3 (B). Merged image is shown (C). Arrows indicate <i>agr2</i>-expressing goblet cells and arrowheads specify <i>glucagon</i>-expressing enteroendocrine cells. Scale bars represent 100 µm.</p

<i>agr2</i> morpholino antisense oligomer knockdown analyses.

<p>(A) Phenotype comparison among wild type, agr2–5 mmMO1 and 5 mmMO2-coinjected, and agr2-MO1 and agr2-MO2-coinjected embryos at 24 and 104 hpf. (B) Whole-mount immunohistochemistry demonstrates that coinjection of agr2-MO1 and agr2-MO2 prevents the synthesis of Agr2 protein in intestinal goblet cells. Confocal images of either wild type, agr2–5 mmMO1 and 5 mmMO2-coinjected, or agr2-MO1 and agr2-MO2-coinjected 104 hpf embryos were recorded under transmitted mode (a, d, g) or using 494/517 nm excitation/emission wavelengths (b, e, h). Merged images are shown (c, f, i). (C) Green fluorescence was not detected in agr2-MO1, agr2-MO2 and <i>CMV</i>-<i>agr2</i>-<i>mo</i>-<i>GFP</i> coinjected (c) 30 hpf embryos, whereas bright green fluorescence was observed in <i>CMV</i>-<i>agr2</i>-<i>mo</i>-<i>GFP</i>-injected (a) and agr2–5 mmMO1, agr2–5 mmMO2 and <i>CMV</i>-<i>agr2</i>-<i>mo</i>-<i>GFP</i> coinjected (b) 30 hpf embryos. Scale bars represent 100 µm.</p

Nitrogen-Doped Graphene Sheets Grown by Chemical Vapor Deposition: Synthesis and Influence of Nitrogen Impurities on Carrier Transport

A significant advance toward achieving practical applications of graphene as a two-dimensional material in nanoelectronics would be provided by successful synthesis of both n-type and p-type doped graphene. However, reliable doping and a thorough understanding of carrier transport in the presence of charged impurities governed by ionized donors or acceptors in the graphene lattice are still lacking. Here we report experimental realization of few-layer nitrogen-doped (N-doped) graphene sheets by chemical vapor deposition of organic molecule 1,3,5-triazine on Cu metal catalyst. When reducing the growth temperature, the atomic percentage of nitrogen doping is raised from 2.1% to 5.6%. With increasing doping concentration, N-doped graphene sheet exhibits a crossover from p-type to n-type behavior accompanied by a strong enhancement of electron–hole transport asymmetry, manifesting the influence of incorporated nitrogen impurities. In addition, by analyzing the data of X-ray photoelectron spectroscopy, Raman spectroscopy, and electrical measurements, we show that pyridinic and pyrrolic N impurities play an important role in determining the transport behavior of carriers in our N-doped graphene sheets

Low Temperature Mitigates Cardia Bifida in Zebrafish Embryos

<div><p>The coordinated migration of bilateral cardiomyocytes and the formation of the cardiac cone are essential for heart tube formation. We investigated gene regulatory mechanisms involved in myocardial migration, and regulation of the timing of cardiac cone formation in zebrafish embryos. Through screening of zebrafish treated with ethylnitrosourea, we isolated a mutant with a hypomorphic allele of <i>mil</i> (<i>s1pr2</i>)/<i>edg5</i>, called <i>s1pr2^as10</i> (<i>as10</i>). Mutant embryos with this allele expressed less <i>mil</i>/<i>edg5</i> mRNA and exhibited cardia bifida prior to 28 hours post-fertilization. Although the bilateral hearts of the mutants gradually fused together, the resulting formation of two atria and one tightly-packed ventricle failed to support normal blood circulation. Interestingly, cardia bifida of <i>s1pr2^as10</i> embryos could be rescued and normal circulation could be restored by incubating the embryos at low temperature (22.5°C). Rescue was also observed in <i>gata5</i> and <i>bon</i> cardia bifida morphants raised at 22.5°C. The use of DNA microarrays, digital gene expression analyses, loss-of-function, as well as mRNA and protein rescue experiments, revealed that low temperature mitigates cardia bifida by regulating the expression of genes encoding components of the extracellular matrix (<i>fibronectin 1</i>, <i>tenascin-c</i>, <i>tenascin-w</i>). Furthermore, the addition of N-acetyl cysteine (NAC), a reactive oxygen species (ROS) scavenger, significantly decreased the effect of low temperature on mitigating cardia bifida in <i>s1pr2^as10</i> embryos. Our study reveals that temperature coordinates the development of the heart tube and somitogenesis, and that extracellular matrix genes (<i>fibronectin 1</i>, <i>tenascin-c</i> and <i>tenascin-w</i>) are involved.</p></div

Expression of two <i>tenascin</i> genes is affected by temperature.

<p><i>In situ</i> hybridization against <i>tenascin-c</i> (<i>tnc</i>) (A-H) and <i>tenascin-w</i> (<i>tnw</i>) (L-O) in 22-ss wild-type (WT) and <i>s1pr2^as10</i> (<i>as10</i>) mutant embryos raised at 28.5°C or 22.5°C. Expression of <i>tnc</i> increased in the pharyngeal arches (white arrows in B and D) and the cells between the brain and eyes of embryos raised at 22.5°C, but was unaffected in the trunk somite region (E-H). (I) qRT-PCR revealed a trend towards increased expression of <i>tnc</i> mRNA in <i>s1pr2^as10</i> mutant embryos raised at 22.5°C. (J) Knockdown of <i>tnc</i> expression with <i>tnc</i>-MO1 in <i>s1pr2^as10</i> mutants increased the percentage of 26-ss embryos raised at 22.5°C with the Class III cardia bifida phenotype. (K) Injection of <i>s1pr2^as10</i> mutant embryos raised at 28.5°C with human TNC protein partially rescued cardia bifida phenotypes at 24 hpf. (L-O) Decreased <i>tnw</i> expression in all tissues, including scattered epidermal cells in the head (black arrows in M and O) was observed in both 22-ss WT and <i>s1pr2^as10</i> mutants raised at 22.5°C. (P) qRT-PCR was used to confirm that expression of <i>tnw</i> mRNA is significantly reduced in 22-ss WT and <i>s1pr2^as10</i> mutant embryos raised at 22.5°C. (Q) Knockdown of <i>tnw</i> with <i>tnw</i>-MO1 in <i>s1pr2^as10</i> mutant embryos raised at 28.5°C partially rescued cardia bifida phenotypes at 24 hpf. (R) Injection of <i>s1pr2^as10</i> mutant embryos raised at 22.5°C with 100 pg <i>tnw</i> mRNA increased the percentage of 26-ss embryos with the Class III cardia bifida phenotype. Scale bars  = 100 µm. The error bars indicate the standard error. Statistical significance was determined using Student’s <i>t</i>-test. * indicates <i>p</i><0.05, ** indicates <i>p</i><0.01, *** indicates <i>p</i><0.001.</p