Making Risk Visible. The role of images in the assessment of (cancer) genetic risk

Whilst analysis of 'risk' (in its many conceptual shapes) has loomed large in both medicine and social sciences over the past 25 years, detailed investigations as to how risk assessments are actually put together (in either lay or professional contexts) are few in number. The studies that are available usually focus on the use of words or everyday conversation in assembling risk. Talking about risk is, of course, important, but what tends to be ignored is the fact that risk can be and is often made visible. For example, it can be made visible through the use of tables, charts, diagrams and various kinds of sophisticated laboratory images. This paper concentrates on the role of such images in the context of a cancer genetics clinic and its associated laboratory. Precisely how these images are tied into the production of risk estimates, how professionals discuss and use such images in clinical work, and how professionals reference them to display facts about risk is the focus of the paper. The paper concludes by highlighting the significance of different kinds of visibility for an understanding of genetic abnormalities and how such differences might impact on the attempts of lay people to get to grips with risk.

Systematic study of visible transitions in Ti-like high Z ions

The magnetic dipole transitions between fine structure levels in the ground term of Ti-like ions, (3d(4)) D-5(2)-D-5(3), were investigated by observation of visible and near-UV light for several elements with atomic numbers from 51 to 78. The wavelengths are compared with theoretical values we recently calculated. The differences between the present calculations and measurements are less than 0.6%. The anomalous wavelength stability predicted by Feldman, Indelicato and Sugar [J. Opt. Soc. Am. B 8, 3 (1991)] was observed. We attribute this anomalous wavelength stability to the transition from LS to JJ coupling and the asymptotic behavior of the transition energies in the intermediate coupling regime.

Short pulse pumped X-ray lasers

Double laser pulses of duration similar to 75 ps and short laser pulses similar to 1 ps superimposed on longer duration background pulses have been shown to efficiently pump lasing in Ne-like and Ni-like ions. For the 75 ps pumping, X-ray laser output without travelling wave pumping is shown to be well-described by a model of ASE output. With I ps pumping, the X-ray laser output with different velocity travelling wave pumping is well-fitted with an extension to the ASE model allowing for travelling wave excitation of the gain along the plasma line. The model is used to investigate the production of short (<1 ps) x-ray laser pulses and the effects of non-ideal travelling wave velocities on the X-ray laser output. Resonance line spectra of emission perpendicular to the plasma line are measured and simulated. It is shown that an accurate opacity model for the more intense Ne-like ions is needed to correctly simulate the spectra.

Visible and Near-Infrared Emission by Samarium(III)-Containing Ionic Liquid Mixtures

Highly luminescent anionic samarium(III) beta-diketonate and dipicolinate complexes were dissolved in the imidazolium ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C(6)mim][Tf2N]. The solubility of the complexes in the ionic liquid was ensured by a careful choice of the countercation of the samarium(III) complex. The samarium(III) complexes that were considered are [C(6)mim][SM(tta)(4)], where tta is 2-thenoyltrifluoroacetonate; [C(6)mim][Sm(nta)(4)], where nta is 2-naphthoyltrifluoroacetonate; [C(6)mim][Sm(hfa)(4)], where hfa is hexafluoroacetylacetonate; and [choline](3)-[Sm(dpa)(3)], where dpa is pyridine-2,6-dicarboxylate (dipicolinate) and [choline](+) is (2-hydroxyethyl)trimethyl ammonium. The crystal structures of the tetrakis samarium(III) P-diketonate complexes revealed a distorted square antiprismatic coordination for the samarium(III) ion in all three cases. Luminescence spectra were recorded for the samarium(III) complexes dissolved in the imidazolium ionic liquid as well as in a conventional solvent, that is, acetonitrile or water for the beta-diketonate and dipicolinate complexes, respectively. These experiments demonstrate that [C(6)mim][Tf2N] is a suitable spectroscopic solvent for studying samarium(III) luminescence. High-luminescence quantum yields were observed for the samarium(III) beta-diketonate complexes in solution.

Fully fluorinated imidodiphosphinate shells for visible- and NIR-Emitting lanthanides: Hitherto unexpected effects of sensitizer fluorination on lanthanide emission properties

In this paper we demonstrate that the effect of aromatic C-F substitution in ligands does not always abide by conventional wisdom for ligand design to enhance sensitisation for visible lanthanide emission, in contrast with NIR emission for which the same effect coupled with shell formation leads to unprecedented long luminescence lifetimes. We have chosen an imidodiphosphinate ligand, N-{P,P-di-(pentafluorophinoyl)}-P,P-dipentafluoro-phenylphosphinimidic acid (HF(20)tpip), to form ideal fluorinated shells about all visible- and NIR-emitting lanthanides. The shell, formed by three ligands, comprises twelve fully fluorinated aryl sensitiser groups, yet no-high energy X-H vibrations that quench lanthanide emission. The synthesis, full characterisation including X-ray and NMR analysis as well as the photophysical properties of the emissive complexes [Ln(F(20)tpip)(3)], in which Ln=Nd, Sm, Eu, Gd, Tb, Dy, Er, Yb, Y, Gd, are reported. The photophysical results contrast previous studies, in which fluorination of alkyl chains tends to lead to more emissive lanthanide complexes for both visible and NIR emission. Analysis of the fluorescence properties of the HF(20)tpip and [Gd(F(20)tpip)(3)] reveals that there is a low-lying state at around 715 nm that is responsible for partially quenching of the signal of the visible emitting lanthanides and we attribute it to a pi-sigma* state. However, all visible emitting lanthanides have long lifetimes and unexpectedly the [Dy(F(20)tpip)(3)] complex shows a lifetime of 0.3 ms, indicating that the elimination of high-energy vibrations from the ligand framework is particularly favourable for Dy. The NIR emitting lanthanides show strong emission signals in powder and solution with unprecedented lifetimes. The luminescence lifetimes of [Nd(F(20)tpip)(3)], [Er(F(20)tpip)(3)] and [Yb(F(20)tpip)(3)] in deuteurated acetonitrile are 44, 741 and 1111 mu s. The highest value observed for the [Yb(F(20)tpip)(3)] complex is more than half the value of the Yb ion radiative lifetime.

Rare-earth complexes of ferrocene-containing ligands: Visible-light excitable luminescent materials

The ferrocene-derivatives bis(ferrocenyl-ethynyl)-1,10-phenanthroline (Fc(2)phen) and ferrocenoyltrifluoroacetone (Hfta) have been used to synthesize ferrocene-containing rare-earth beta-diketonate complexes. The complexes [Ln(tta)(3)(Fc(2)phen)] and [Ln(fta)(3)(phen)] (where Ln = La, Nd, Eu, Yb) show structural similarities to the tris(2-thenoyltrifluoroacetonate)(1,10-phenanthroline)lanthanide(III) complexes, [Ln(tta)(3)(phen)]. The coordination number of the lanthanide ion is 8, and the coordination sphere can be described as a distorted dodecahedron. However, the presence of the ferrocene moieties shifts the ligand absorption bands of the rare-earth complexes to longer wavelengths so that the complexes can be excited not only by ultraviolet radiation but also by visible light of wavelengths up to 420 nm. Red photoluminescence is observed for the europium(III) complexes and near-infrared photoluminescence for the neodymium(III) and ytterbium(III) complexes. The presence of the ferrocene groups makes the rare-earth complexes hydrophobic and well-soluble in apolar organic solvents.

Rare-earth nitroquinolinates: Visible-light-sensitizable near-infrared emitters in aqueous solution

Water-soluble, stable, and easily synthesizable 1:4 complexes of rare-earth ions with 8-hydroxy-5-nitroquinolinate ligands have been prepared. These complexes can be sensitized by visible light with wavelengths up to 480 nm and show near-infrared emission in aqueous solution. The incorporation of a nitro group in the quinoline moiety shifts its absorption bands to longer wavelengths and also increases its molar absorptivity by a factor of 2.5, thereby significantly enhancing its light-harvesting power. The presence of the nitro group also increases the solubility of the resulting complexes, making them water-soluble. (c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007.

Visible-light-sensitized near-infrared luminescence from rare-earth complexes of the 9-hydroxyphenalen-1-one ligand

The unique absorption properties of the 9-hydroxyphenalen-1-one (HPHN) ligand have been exploited to obtain visible-light-sensitizable rare-earth complexes in 1: 3 and 1: 4 metal-to-ligand ratios. In both stoichiometries (1:3,tris,Ln(PHN)3;1:4, tetrakis, A[ Ln( PHN)(4)], with Ln being a trivalent rare-earth ion and A being a monovalent cation), the complexes of Nd(III),Er( III), and Yb(III) show typical near-infrared luminescence upon excitation with visible light with wavelengths up to 475 nm. The X-ray crystal structures of the tris complexes show solvent coordination to the central rare-earth ion, whereas in the tetrakis complexes, the four PHN-ligands form a protective shield around the central ion, preventing small solvent molecules from coordinating to the rare-earth ion, at least in the solid state.

Visible light sensitisation of europium(III) luminescence in a 9-hydroxyphenal-1-one complex

The 9-hydroxyphenal-1-one ligand forms stable 3 : 1 complexes with trivalent lanthanides, in which it acts as an antenna suitable for the visible light excitation ( up to 475 nm) of the trivalent europium ion.