We present results of near-IR long-slit spectroscopy in the J and K bands of the Seyfert 2 galaxies NGC 2110 and Circinus. Our goal is to investigate the gaseous distribution, excitation, reddening ...and kinematics, looking for signatures of the molecular torus hypothesized in unified models to both obscure and collimate the nuclear radiation. The two galaxies show extended emission in the IR emission lines Fe ii λ 1.257 μm, Pa β and H2 v=1-0 S(1), both along the major axis of the galaxy disc and perpendicular to it. In NGC 2110, the emission-line ratio Fe ii/Pa β increases towards the nucleus, where its value is ≈ 7. Further, the nuclear Fe ii and Pa β lines are broader (FWHM ̃ 500 km s−1) than the H2 line (FWHM ≤ 300 km s−1). Both these results suggest that shocks, driven by the radio jet, are an important source of excitation of Fe ii, while the H2 excitation is dominated by X-rays from the nucleus. Br γ is only observed at the nucleus, where H2/Br γ≈ 3. In the case of Circinus, both Fe ii/Pa β and H2/Br γ decrease from ≈ 2 at 4 arcsec from the nucleus to nuclear values of ≈ 0.6 and ≈ 1, respectively, suggesting that the starburst dominates the nuclear excitation, while the active galactic nucleus (AGN) dominates the excitation further out (r ≥ 2 arcsec). For both galaxies, the gaseous kinematics are consistent with circular rotation in the plane of the disc. Our rotation curves suggest that the nucleus (identified with the peak of the IR continuum) is displaced from the kinematic centre of the galaxies. This effect has been observed previously in NGC 2110 based on the kinematics of optical emission lines, but the displacement is smaller in the infrared, suggesting the effect is related to obscuration. The continuum J-K colours indicate a red stellar population in NGC 2110 and a reddened young stellar population in Circinus, outside the nucleus. Right at the nucleus of both galaxies, the colours are redder, apparently a result of hot dust emission, perhaps from the inner edge of a circumnuclear torus. In NGC 2110, the signature of the hot dust emission is particularly clear in the K band, being seen as an additional component superimposed on the continuum observed in the J band.
Complexes of Ag(I) with pendant arm N-heterocyclic carbenes have been prepared via reaction of silver(I) oxide with the corresponding imidazolium precursors.
Silver(I) complexes of heterobidentate ...ligands that incorporate one or two N-heterocyclic carbene moieties coupled with an alcohol or amine group have been made by direct deprotonation of ligands of the form HOCR
1R
2CH
2(1-HC{NCHCHNR})X, H
2L
1X (X
=
Br, I), H
2NR
1CHR
2CHR
2(1-HC{NCHCHNR})Br
2 H
3L
2X
2 (X
=
Cl, Br), and H
2N{CH
2CH
2(1-HCNCHCHNMes)}
2X
3 H
4L
3X
3 (X
=
Cl, Br). Silver(I) oxide is sufficiently basic to deprotonate both the imidazolium and the alcohol functional groups of all but one of the L
1 ligand precursors, to afford rare examples of silver alkoxide complexes Ag(L
1), stabilised by the soft donor carbene. Another complex of L
1 is characterised as the carbene alcohol adduct Ag(HL
1)
2I. The analogous reactions of silver(I) oxide with the amino imidazolium precursors afford silver amino-carbenes Ag(HL
2)Br with the potentially bidentate L
2 ligand, and Ag(HL
3)X (X
=
Cl, Br) with the potentially tridentate L
3 ligand. A single crystal X-ray diffraction study of the latter complex confirms that the neutral amine of the potentially tridentate L
3 ligand is unco-ordinated; instead the structure contains discrete chains of T-shaped silver bis(carbene) halide moieties that bridge to form a zig-zag 2-connected polymer. Protonolysis of two of the silver alkoxide and amino adducts, Ag(L
1a) and Ag(HL
2a)Br, affords imidazolium complexes salts H
2L
1aAgCl
2 and Ag(H
2L
2a)BrAgBr
2 that retain the Ag(I) centre as complex counterions. The single crystal X-ray structures of these salts have been determined and show the silver(I) cations are now incorporated into ladders or chains as silver(I) halo-anions, and a silver amine dative bond is present in the latter complex.
We examined individual clones of murine NIH 3T3 cells, transformed with the human bladder cancer (T24) H-ras oncogene, for p21 expression and for experimental metastatic ability in the ...immunodeficient chick embryo. We found that the clones were heterogeneous for both of these properties. In general, p21 expression was a good predictor of metastatic ability of the clones. Cells from poorly metastatic clones were passaged in the chick embryo metastasis assay to determine whether cells with increased metastatic ability could be selected. We found that the selected cells were more metastatic and that substantial increases in expression of p21 also accompanied this increase in metastatic ability. The relationship between p21 expression and metastatic ability appeared linear, with a high correlation coefficient (r = .85), suggesting that in this model system quantitative increases in metastatic properties can result from increased expression of the ras oncogene protein product p21.
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