Astronomical Distance Determination in the Space Age: Secondary Distance Indicators

The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)

Detection of Zn-containing proteins in slug (Genus Arion) tissue using laser ablation ICP-MS after separation by gel electrophoresis

Assessing the inventory of biological systems in respect to metal species is a growing area of life science research called metallomics. Slugs are of special interest as monitor organisms for environmental contaminations. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied to map the distribution of total Zn in a section of a slug sample and to detect Zn-containing proteins after one-dimensional separation by gel electrophoresis (Blue Native PAGE). Interestingly, by far the largest fraction of protein bound Zn was explained by three sharp and prominent bands at 75,100 and 150 kDa. Analysis of tryptic digests of selected bands using MALDI-TOF-MS and public databases failed to identify proteins within the Zn bands what may be due to coverage gaps concerning the species anon ater. Three non-Zn containing bands could be assigned to proteins known from other mollusc species. (C) 2011 Elsevier B.V. All rights reserved

Evaluation of metal distributions in small samples of mouse brain lesions (hematoma) by inductively coupled plasma mass spectrometry after sampling by laser microdissection (LMD)

Laser microdissection (LMD) used for sample preparation was combined off-line with inductively coupled plasma mass spectrometry (ICP-MS) to evaluate metal distributions in mouse brain with hematoma lesion. Small amounts (from 0.014 to 0.338 mg) of tissue were sampled from selected regions of the brain, with a hematoma lesion and also from regions without hematoma. The obtained samples were decomposed in closed vessel in a microwave oven and a micronebulizer in conjuction with a desolvation system was used for introducing the solution of the sample into the plasma. Accuracy was evaluated using certified reference materials (bovine liver and mussel tissue), whilst the agreement between the concentrations found with those certified was better than 85%. The limits of detection (LODs) of Cu, Fe and Zn for the small mouse brain tissue samples were 12.4, 12.5 and 9.6 mu g g(-1), respectively. The LODs of K and Na were 1.07 and 0.24 mg g(-1), respectively. The distribution of K. Na, Cu, Fe and Zn in the selected regions of the mouse brain was evaluated. It was observed that the Fe, Na and Zn concentrations were approximately 2-10 times higher in the hematoma region (inside and around the hematoma) than in the control (region without hematoma). The LMD system demonstrated to be useful for sampling small amounts of biological tissue from regions of interest for further analysis by ICP-MS. (C) 2011 Elsevier B.V. All rights reserved

Bioimaging of metals in thin mouse brain section by laser ablation inductively coupled plamsa mass spectrometry: novel online quantification strategy using aqueous standards

A novel solution-based calibration method for quantitative spatial resolved distribution analysis (imaging) of elements in thin biological tissue sections by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) is described. A dual flow of the carrier and nebulizer gas is used to transport the aerosol of the laser ablated solid sample (brain tissue) and that of the nebulized aqueous standard into inductively coupled plasma (ICP) source, respectively. Both aerosols are introduced separately in the injector tube inside a special ICP torch and then mixed in the inductively coupled plasma. Calibration curves were obtained via two different calibration strategies: (i) solution based calibration and (ii) with a set of well characterized homogeneous brain laboratory standards. In the first approach matrix matching is performed by solution nebulization of a series of aqueous standards with defined analyte concentrations and simultaneous laser ablation of brain homogenate followed by nebulization of 2% (v/v) HNO3 and laser ablation of a whole brain slice (line by line). In the second approach of calibration a set of brain homogenates with defined analyte concentrations is analyzed by LA-ICP-MS followed by the imaging of brain tissue under the same experimental conditions (dry plasma). Calibration curves of elements of interest (e. g., Li, Na, Al, K, Ca, Ti, V, Mn, Ni, Co, Cr, Cu, Zn, As, Se, Rb, Sr, Y, Cd, Ba, La, Ce, Nd, Gd, Hg, Pb, Bi and U) were obtained using (i) aqueous standards or (ii) the set of synthetic laboratory standards prepared from a mouse brain homogenate doped with elements at defined concentrations. The ratio of the slope of the calibration curves (obtained by using aqueous standards and solid standards) was applied to correct the differences of sensitivity among ICP-MS and LA-ICP-MS. Quantitative images of Li, Mn, Fe, Cu, Zn and Rb in mouse brain were obtained under wet plasma condition (nebulization of HNO3 solution in parallel with ablation of solid brain sample)

Biomonitoring of essential and toxic metals in single hair using on-line solution-based calibration in laser ablation inductively coupled plasma mass spectrometry

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a powerful and sensitive surface analytical technique for the determination of concentration and distribution of trace metals within biological systems at micrometer spatial resolution. LA-ICP-MS allows easy quantification procedures if suitable standard references materials (SRM) are available. In this work a new SRM-free approach of solution-based calibration method in LA-ICP-MS for element quantification in hair is described. A dual argon flow of the carrier gas and nebulizer gas is used. A dry aerosol produced by laser ablation (LA) of biological sample and a desolvated aerosol generated by pneumatic nebulization (PN) of standard solutions are carried by two different flows of argon as carrier or nebulizer gas, respectively and introduced separately in the injector tube of a special ICP torch, through two separated apertures. Both argon flows are mixed directly in the ICP torch. External calibration via defined standard solutions before analysis of single hair was employed as calibration strategy. A correction factor, calculated using hair with known analyte concentration (measured by ICP-MS), is applied to correct the different elemental sensitivities of ICP-MS and LA-ICP-MS. Calibration curves are obtained by plotting the ratio of analyte ion M(+)/(34)S(+) ion intensities measured using LA-ICP-MS in dependence of analyte concentration in calibration solutions. Matrix-matched on-line calibration in LA-ICP-MS is carried out by ablating of human hair strands (mounted on a sticky tape in the LA chamber) using a focused laser beam in parallel with conventional nebulization of calibration solutions. Calibrations curves of Li, Na, Mg, Al, K, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Sr, Mo, Ag, Cd, I, Hg, Pb, Tl, Bi and U are presented. The linear correlation coefficients (R) of calibration curves for analytes were typically between 0.97 and 0.999. The limits of detection (LODs) of Li, V, Mn, Ni, Co, Cu, Sr, Mo, Ag, Ba, Cd, I, Hg, Pb, Bi and U in a single hair strand were in the range of 0.001-0.90 μg g(-1), whereas those of Cr and Zn were 3.4 and 5.1 μg g(-1), respectively. The proposed quantification strategy using on-line solution-based calibration in LA-ICP-MS was applied for biomonitoring (the spatial resolved distribution analysis) of essential and toxic metals and iodine in human hair and mouse hair