bluuebunny/crossref_metadata_2025 huggingface dataset:
Method of Data Reduction and Uncertainty Estimation for Platinum‐Group Element Data Using Inductively Coupled Plasma‐Mass Spectrometry
Authors: Ely James C. , Neal Clive R.
Published: May 2007

A data reduction method is described for determining platinum‐group element (PGE) abundances by inductively coupled plasma‐mass spectrometry (ICP‐MS) using external calibration or the method of standard addition. Gravimetric measurement of volumes, the analysis of reference materials and the use of procedural blanks were all used to minimise systematic errors. Internal standards were used to correct for instrument drift. A linear least squares regression model was used to calculate concentrations from drift‐corrected counts per second (cps). Furthermore, mathematical manipulations also contribute to the uncertainty estimates of a procedure. Typical uncertainty estimate calculations for ICP‐MS data manipulations involve: (1) Carrying standard deviations from the raw cps through the data reduction or (2) calculating a standard deviation from multiple final concentration calculations. It is demonstrated that method 2 may underestimate the uncertainty estimate of the calculated data. Methods 1 and 2 do not typically include an uncertainty estimate component from a regression model. As such models contribute to the uncertainty estimates affecting the calculated data, an uncertainty estimate component from the regression must be included in any final error calculations. Confidence intervals are used to account for uncertainty estimates from the regression model. These confidence intervals are simpler to calculate than uncertainty estimates from method 1, for example. The data reduction and uncertainty estimation method described here addresses problems of reporting PGE data from an article in the literature and addresses both precision and accuracy. The method can be applied to any analytical technique where drift corrections or regression models are used.
Determination of Rare Earth Elements, Y, Th, Zr, Hf, Nb and Ta in Geological Reference Materials G‐2, G‐3, SCo‐1 and WGB‐1 by Sodium Peroxide Sintering and Inductively Coupled Plasma‐Mass Spectrometry
Authors: Meisel Thomas , Schöner Nina , Paliulionyte Vaida , Kahr Elisabeth
Published: May 2007

Data are reported for rare earth elements (REE), Y, Th, Zr, Hf, Nb and Ta in four geological reference materials using sodium peroxide (Na2O2) sintering and inductively coupled plasma‐mass spectrometry. The described procedure was used by students during their thesis work. A compilation of their reference material data acquired over one year of laboratory work demonstrates the ease and reliability of the method and the high reproducibility of the analytical results. Relative standard deviations of up to thirty six measurements of one reference material were lower than 5% for Y and the REE. Reproduciblities of Zr, Hf, Nb, Ta and Th were higher at between 5% and 10%, and can be attributed to the inhomogeneous distribution of zircon and other trace mineral phases and uncorrected drift effects. The concentration data are compared to reference and literature values and demonstrate that the procedure is also accurate. New data on G‐3 show some systematic deviations from G‐2, which are statistically significant.
The Preparation and Preliminary Characterisation of Four New Geological Survey of Japan Geochemical Reference Materials: Soils, JSO‐1 and JSO‐2; and Marine Sediments, JMS‐1 and JMS‐2
Authors: Terashima Shigeru , Imai Noboru , Taniguchi Masahiro , Okai Takashi , Nishimura Akira
Published: May 2007

Four new geochemical reference materials, soils JSO‐1 and JSO‐2, and marine sediments JMS‐1 and JMS‐2, have been prepared by the Geological Survey of Japan (GSJ) for collaborative studies on their chemical composition. In the case of JSO‐2, thirty one compounds were artificially added to a natural soil, mostly as oxides, in order to provide a soil reference material that contains known chemical forms of minor and trace elements. Homogeneity test results and provisional values of thirty seven major, minor and trace elements are presented to support future collaborative analyses. The homogeneity tests showed that all elements studied can be considered to be homogeneously distributed. A description of the geological and mineralogical characteristics of the materials is also given.
Determination of Trace Elements in BCS CRM 313/1 (BAS) and NIST SRM 1830 by Inductively Coupled Plasma‐Mass Spectrometry and Instrumental Neutron Activation Analysis
Authors: Flem Belinda , Bédard L. Paul
Published: May 2007

In the past, there has been little interest in the trace element characteristics of quartz, and in consequence little activity in the trace element characteristics of reference materials with high silicon content. The main purpose of this paper is to contribute to the characterisation of two international certified reference materials, BCS 313/1 from the Bureau of Analysed Samples, (BAS), UK and SRM 1830 from the National Institute of Standards and Technology (NIST), USA. BCS 313/1 was analysed by laser ablation inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS), solution ICP‐MS and instrumental neutron activation analysis (INAA). NIST SRM 1830 was analysed by LA‐ICP‐MS and INAA. Analytical results are reported for more than forty elements, most of them for the first time. For most elements, the results obtained by the different methods agree within 15 % relative. The recent, heightened interest in quartz and in particular the precise determination of trace0element contents in natural quartz samples requires the use of well characterised reference materials such as BCS 313/1 and SRM 1830, to which this study is designed to contribute.
Determination of the “Difficult” Elements Ag, B, Ge, Mo, Sn, Tl and W in Geochemical Reference Samples and Silicate Rocks of the GeoPT Proficiency Testing Series by DC Arc Atomic Emission Spectrometry
Authors: Kuznetsova Albina I. , Chumakova Nina L.
Published: May 2007

Reference samples of rocks from the Institute of Geochemistry, Irkutsk (IGI) and the Research Institute of Applied Physics, Irkutsk University (RIAP) and silicate rocks from the GeoPT proficiency testing series were analysed with the aim of determining Ag, B, Ge, Mo, Sn, Tl and W abundances by an atomic‐emission method with air‐stabilized D.C. arc excitation. Many of the results reported are without recommended or assigned values. The results are compared with compilation data from the literature and, where possible, with assigned values for samples of the GeoPT series.
Isotope Dilution with Matrix Element Removal: A Key for High‐Precision, High‐Accuracy Trace Analysis of Geological Samples Using Inductively Coupled Plasma‐Mass Spectrometry
Authors: Pin Christian , Le Fèvre Brieuc
Published: May 2007

The isotope dilution (ID) method requires only the measurement of mass and isotopic mass ratios. For this reason, ID is considered a primary method of analysis, capable of higher precision and accuracy than comparative methods used in conventional instrumental analysis, that are based on calibration relative to reference materials. Compared to thermal ionisation mass spectrometers, inductively coupled plasma source‐mass spectrometers (ICP‐MS) benefit from several practical advantages, including direct liquid sampling at atmospheric pressure, a multi‐element capability, high ionisation efficiency, fast scanning capability and widespread availability. These features greatly improve sample throughput, thereby allowing the isotope dilution method to be used on a routine basis. In turn, ID alleviates the need for quantitative sample handling, and thus makes separation of the analytes from matrix elements much easier. This allows ICP‐MS instruments to be used under optimal conditions, because it is possible to use advanced, high efficiency sample introduction systems without resorting to large dilution factors. Moreover, the cleanliness of the sampling interface and ion optics is preserved, thereby allowing optimum instrumental performance to be maintained for extended periods, so reducing maintenance costs. Examples are given in this review to highlight the potential of isotope dilution combined with analyte separation for achieving high precision in trace element analysis of geochemical samples.
Determination of Forty Two Major and Trace Elements in USGS and NIST SRM Glasses by Laser Ablation‐Inductively Coupled Plasma‐Mass Spectrometry
Authors: Gao Shan , Liu Xiaomin , Yuan Honglin , Hattendorf Bodo , Günther Detlef , Chen Liang , Hu Shenhong
Published: May 2007

Forty two major (Na, Mg, Ti and Mn) and trace elements covering the mass range from Li to U in three USGS basalt glass reference materials BCR‐2G, BHVO‐2G and BIR‐1G were determined using laser ablation‐inductively coupled plasma‐mass spectrometry. Calibration was performed using NIST SRM 610 in conjunction with internal standardisation using Ca. Determinations were also made on NIST SRM 612 and 614 as well as NIST SRM 610 as unknown samples, and included forty five major (Al and Na) and trace elements. Relative standard deviation (RSD) of determinations was below 10% for most elements in all the glasses under investigation. Consistent exceptions were Sn and Sb in BCR‐2G, BHVO‐2G and BIR‐1G. For BCR‐2G, BHVO‐2G and BIR‐1G, clear negative correlations on a logarithmic scale exist between RSD and concentration for elements lower than 1500 μg g‐1 with logarithmic correlation coefficients between ‐0.75 and ‐0.86. There is also a clear trend of increasing RSD with decreasing concentration from NIST SRM 610 through SRM 612 to SRM 614. These suggest that the difference in the scatter of apparent element concentrations is not due to chemical heterogeneity but reflects analytical uncertainty. It is concluded that all these glasses are, overall, homogeneous on a scale of 60 μm.

Our first results on BHVO‐2G and BIR‐1G showed that they generally agreed with BHVO‐2/BHVO‐1 and BIR‐1 within 10% relative. Exceptions were Nb, Ta and Pb in BHVO‐2G, which were 14‐45% lower than reference values for BHVO‐2 and BHVO‐1. Be, Ni, Zn, Y, Zr, Nb, Sn, Sb, Gd, Tb, Er, Pb and U in BIR‐1G were also exceptions. However, of these elements, Be, Nb, Sn, Sb, Gd, Tb, Pb and U gave results that were consistent within an uncertainty of 2s between our data and BIR‐1 reference values. Results on NIST SRM 612 agreed well with published data, except for Mg and Sn. This was also true for elements with m/z 85 (Rb) in the case of NIST SRM 614.

The good agreement between measured and reference values for Na and Mg in BCR‐2G, BHVO‐2G and BIR‐1G, and for Al and Na in NIST SRM 610, 612 and 614 up to concentrations of at least several weight percent (which were possible to analyse due to the dynamic range of 108) indicates the suitability of this technique for major, minor and trace element determinations.
Laser Ablation ICP‐MS Analysis of Geological Materials Prepared as Lithium Borate Glasses
Authors: Eggins Stephen M.
Published: May 2007

A simple, rapid and precise method is described for determining trace elements by laser ablation (LA)‐ICP‐MS analysis in bulk geological materials that have been prepared as lithium borate glasses following standard procedures for XRF analysis. This approach reliably achieves complete sample digestion and provides for complementary XRF and LA‐ICP‐MS analysis of a full suite of major and trace elements from a single sample preparation. Highly precise analysis is enabled by rastering an ArF excimer laser (λ= 193nm) across fused samples to deliver a constant sample yield to the mass spectrometer without inter‐element fractionation effects during each analysis. Capabilities of the method are demonstrated by determination of twenty five trace elements (Sc, Ti, V, Ga, Rb, Sr, Y, Zr, Nb, Cs, Ba, REE, Hf, Ta, Pb, Th and U) in a diverse range of geological reference materials that includes peridotites, basalts, granites, metamorphic rocks and sediments. More than 90% of determinations are indistinguishable from published reference values at the 95% confidence level. Systematic bias greater than 5% is observed for only a handful of elements (Zr, Nb and U) and may be attributed in part to inaccurate calibration values used for the NIST SRM 612 glass in the case of Zr and Nb. Detection limits for several elements, most notably La, are compromised at ultra‐trace levels by impurities in the lithium borate flux but can be corrected for by subtracting appropriate procedural blanks. Reliable Pb analysis has proved problematic due to variable degrees of contamination introduced during sample polishing prior to analysis and from Pt‐crucibles previously used to fuse Pb‐rich samples. Scope exists for extending the method to include internal standard element/isotope spiking, particularly where integrated XRF analysis is not available to characterise major and trace elements in the fused lithium borate glasses prior to LA‐ICP‐MS analysis.
Intercomparison of Boron Isotope and Concentration Measurements. Part II: Evaluation of Results
Authors: Gonfiantini Roberto , Tonarini Sonia , Gröning Manfred , Adorni‐Braccesi Alessandra , Al‐Ammar Assad S. , Astner Marcus , Bächler Sebastien , Barnes Ramon M. , Bassett Randy L. , Cocherie Alain , Deyhle Annette , Dini Andrea , Ferrara Giorgio , Gaillardet Jérôme , Grimm Judith , Guerrot Catherine , Krähenbühl Urs , Layne Graham , Lemarchand Damien , Meixner Anette , Northington D. Jack , Pennisi Maddalena , Reitznerová Eva , Rodushkin Ilia , Sugiura Naoji , Surberg Regina , Tonn Sabine , Wiedenbeck Michael , Wunderli Samuel , Xiao Yingkai , Zack Thomas
Published: May 2007

The Istituto di Geoscienze e Georisorse (IGG), on behalf and with the support of the International Atomic Energy Agency (IAEA), prepared eight geological materials (three natural waters and five rocks and minerals), intended for a blind interlaboratory comparison of measurements of boron isotopic composition and concentration. The materials were distributed to twenty seven laboratories ‐ virtually all those performing geochemical boron isotope analyses in the world ‐which agreed to participate in the intercomparison exercise. Only fifteen laboratories, however, ultimately submitted the isotopic and/or concentration results they obtained on the intercomparison materials. The results demonstrate that interlaboratory reproducibility is not well reflected by the precision values reported by the individual laboratories and this observation holds true for both boron concentration and isotopic composition. The reasons for the discrepancies include fractionations due to the chemical matrix of materials, relative shift of the zero position on the δ11B scale and a lack of well characterized materials for calibrating absolute boron content measurements. The intercomparison materials are now available at the IAEA (solid materials) and IGG (waters) for future distribution.
Investigation of the Matrix Effect of Mg, Si, Ca, Sc, Fe, Y, La and Lu in Pyroxene Composition Synthetic Silicate Glasses by Ion Microprobe
Authors: Lehmann Henry
Published: May 2007

The dependence of the count rate of singly charged secondary ions of the elements Mg, Si, Ca, Sc, Fe, Y, La and Lu on the bulk composition of the sample (known as the matrix effect) was systematically investigated for synthetic silicate glasses using a Cameca IMS 3f ion microprobe. Matrix elements in these samples, with the composition of a Mg‐Fe‐Ca pyroxene, comprised Mg, Si, Ca and Fe to which were added the minor elements Sc, Y, La and Lu (each at 0.1 atom %). The matrix dependence of all elements was determined quantitatively by ratioing their count rate response to the Ca or Fe yields of the sample. Measurements were conducted using four energy offsets: 0 eV, 40 eV, 80 eV and 120 eV (each 20 eV) with primary beam currents of between 0.5 and 3 nA. For the four minor elements investigated, a non‐linear dependence of the absolute sensitivity factors on the Fe content was found at all the energy ranges studied. This matrix effect decreased with increasing secondary ion energy. For the major elements Mg, Si, Ca and Fe, linear as well as non‐linear dependences of the absolute sensitivity factors on the Fe content were found, depending on the element and the energy level considered. Because of their importance in the geosciences, relative sensitivity factors of the elements under study relative to Si as reference element (in some cases also relative to Mg) were determined. For low energy ions, a Fe‐dependent matrix effect also occurred. For Mg, Y, La and Lu, the matrix effect vanished for some values of the secondary ions energy range.
Chemical Analysis of Iron Meteorites by Inductively Coupled Plasma‐Mass Spectrometry
Authors: D'Orazio Massimo , Folco Luigi
Published: May 2007

Iron meteorites were analysed for nineteen siderophile and chalcophile elements by conventional inductively coupled plasma‐mass spectrometry with the specific aim of demonstrating that this technique is an effective alternative to the more routine, yet complex, methodologies adopted in this field such as instrumental or radiochemical neutron activation analysis. Two aliquots of each meteorite sample, in the form of small shavings, were dissolved, one in 6 mol l‐1 HNO3 and the other in aqua regia, and diluted to a final concentration of 1 mg sample per 1 ml of solution, without pre‐concentrating the analytes. Nitric acid solutions were used for the determination of the elements Cr, Co, Ni, Cu, Ga, Ge and As; aqua regia solutions were analysed for the elements Mo, Ru, Rh, Pd, In, Sn, Sb, W, Re, Ir, Pt and Au. Samples were analysed by external calibration, carried out using synthetic multi‐elemental solutions, and internal standardisation (with Be, Rb and Bi selected as internal standards). The results obtained from the analyses of nine geochemically well‐characterized iron meteorites (Canyon Diablo, Odessa, Toluca, Coahuila, Sikhote‐Alin, Buenaventura, Tambo Quemado, Gibeon, NWA 859) with widely variable chemical compositions are in good agreement with literature values for most elements. Detection limits were generally below the lowest concentration observed in iron meteorites. The most notable exception is for Ge, which cannot be successfully determined in the low‐Ge meteorites of groups IVA, IVB and IIIF and a number of ungrouped irons. A test of the overall reproducibility of the adopted method, undertaken by repeatedly analysing the same Odessa IAB meteorite specimen, yielded relative standard deviations (1 s) of between 1 and 6% for all elements except Cr (40%).
The Preparation and Characterisation of Two New Geological Survey of Japan Geochemical Reference Materials: Copper ore JCu‐1 and Zinc ore JZn‐1
Authors: Terashima Shigeru , Sato Kohei , Taniguchi Masahiro , Okai Takashi , Imai Noboru
Published: May 2007

Two new geochemical reference materials, copper ore JCu‐1 and zinc ore JZn‐1 have been prepared by the Geological Survey of Japan (GSJ) for the determination of major and minor elements and isotopic compositions. JCu‐1 is a sample of Cu‐bearing sulfide ore typical of the Kamaishi mine in Iwate Prefecture, Japan, and is composed mainly of hedenbergite, chalcopyrite, quartz and calcite. Pyrrhotite, magnetite and actinolitic amphibole were also commonly found. The Zn‐rich ore, JZn‐1 is a crude ore from the Kamioka Pb‐Zn mine in Gifu Prefecture, Japan. The sample consists of hedenbergite, quartz, calcite, sphalerite and epidote as main crystalline phase. Homogeneity test results showed that all studied constituents including ore elements such as Cu, Pb and Zn can be considered to be homogeneously distributed. Provisional collaborative analyses were carried out in ten laboratories, and the data were evaluated using a robust statistical method using z‐scores. Recommended values for a number of major elements including TiO2, Al2O3, MnO, MgO, CaO, Na2O, K2O, Fe (total), Zn, Cu and Pb were established. In addition, information values for eighteen major, minor and trace elements are presented to support future collaborative analyses.
Multi‐Collector SIMS Determination of Trace Lanthanides in Zircon
Authors: Whitehouse Martin J.
Published: May 2007

A method is presented for the determination of rare earth elements (REE) in zircon (ZrSiO4) using a multi‐collector equipped ion‐microprobe operating at moderately high mass resolution (M/ΔM ˜ 3900). The low abundance light REE (La‐Eu) were measured simultaneously in six ion counting electron multipliers, reducing analytical time to less than half of that in a monocollection routine. Effective mass filtering, moderate energy filtering and careful set up of detector parameters in order to minimise background counts, yielded a highly coherent set of analyses from the 91500 zircon reference sample.
Determination of Platinum‐Group Elements in Geological Reference Materials by High Resolution‐ICP‐MS after Nickel Sulfide Fire‐Assay Collection and Te Co‐Precipitation
Authors: Morcelli Claudia P.R. , Figueiredo Ana Maria G. , Enzweiler Jacinta , Sarkis Jorge E.S. , Jorge Alexandre P.S. , Kakazu Maurício
Published: May 2007

Inductively coupled plasma‐mass spectrometry (ICP‐MS) after NiS fire assay‐Te co‐precipitation was employed in the determination of Ru, Rh, Pd, Os, Ir and Pt at ng g‐1 levels in six platinum‐group element (PGE) geological reference materials. In general, the average of several results was in good agreement with the certified values taking into account respective uncertainties. High relative standard deviations were observed for the reference materials GPt‐3 and GPt‐4. Problems associated with the NiS fire assay procedure and PGE determination at the sub‐10 ng g‐1 level are reviewed and discussed.
Improved Platinum‐Group Element Extraction by NiS Fire Assay from Chromitite Ore Samples Using a Flux Containing Sodium Metaphosphate
Authors: Bédard L. Paul , Barnes Sarah‐Jane
Published: May 2007

Many chromite‐rich rocks contain relatively high concentrations of the platinum‐group elements (PGE). In many cases, the phases carrying PGE occur as either platinum‐group minerals (PGM) or as base metal sulfides in solid solution in sulfides. In some cases, such as the UG‐2 unit of the Bushveld Complex, the PGM are occluded inside chromite grains. Chromites are notably difficult to dissolve in most fluxes and if the chromite contains some PGM the possibility exists that not all the PGE will be recovered during fusion. In this work, shortcomings in published methods of analysis based on the nickel sulfide fire assay procedure were investigated and a new procedure developed based on the addition of sodium metaphosphate to the fusion mixture. Optimum composition of the fusion mixture was found to be 10 g sodium metaphosphate and 9 g silica to 10 g sample, 15 g sodium carbonate, 30 g lithium tetraborate, 7.5 g nickel and 4.5 g sulfur to achieve complete dissolution of chromite grains. The new flux mixture was evaluated by the analysis of reference material CHR‐Pt+ (which is known to contain PGM inside chromite grains) and no undissolved chromite grains were found in the glassy slag. Analysis of the nickel sulfide beads from this fire assay using neutron activation analysis showed similar results for Rh and Ru when compared with published conventional true (or accepted) values, while Au, Ir, Os, Pd and Pt values determined here were 10 to 30% higher than the corresponding published conventional true values. It was concluded that the addition of sodium metaphosphate improved chromite dissolution in the flux and appears to improve PGE recovery.
Pressurised Extraction Using Dilute Ammonia: A Simple Method for Determination of Iodine in Soil, Sediment and Biological Samples by Inductively Coupled Plasma‐Mass Spectrometry
Authors: Bing Li , Xinrong Ma , Lirong Han , Hongxia Yang
Published: May 2007

A simple sample treatment method for the accurate and precise determination of iodine in soil, sediment and biological samples by inductively coupled plasma‐mass spectrometry (ICP‐MS) is described. Iodine in samples was extracted in screw top PTFE‐lined stainless steel bombs using a 10% v/v ammonia solution at 185 C for 18 hours (overnight), after which the extract was introduced into the ICP‐MS for direct measurement. 126Te was employed as the internal standard to compensate for matrix effects and instrument drift. The limit of detection (LOD, three times the standard deviation of the procedural blank solution, expressed as the concentration in the sample solution) was 0.003 ng ml‐‐1. The limit of quantitation (LOQ, ten times the standard deviation of the procedural blank solution, expressed as the concentration in the solid samples, dilution factor DF = 100) was 0.01 μg g‐‐1 (dry mass). The accuracy and precision of the method were demonstrated by analysing different Chinese geological certified reference materials (soils, stream sediments and a hair sample). The measured concentrations were in a good agreement with the certified values indicating that bias in the method was not significant. The precision (n = 10) for different concentrations ranged from 1.82% to 4.32% RSD. Comparison of the ammonia extraction procedure with a “sintering” method indicated that there was no significant difference in results obtained with the two methods for geological soil and stream sediment samples. However, for biological samples, such as hair, kelp, tea etc., the results obtained by the sintering method were far below those of the ammonia extraction method. The ammonia extraction has advantages, as it is simpler than the “sintering” method, and has a lower procedural blank, better detection limits and reproducibility. Due to the simplicity of the method, a high rate of sample throughput is possible.
Fluid Geoanalysis in the Chinese Continental Scientific Drilling Project
Authors: Luo Liqiang , Zhan Xiuchun , Sun Qing
Published: May 2007

Mass spectrometry and chromatography were used in the on‐line and in situ analysis of fluids in the Chinese continental scientific drilling project. The drilling processes and mud have great effects on the identification of fluids. After considering the effects of air components and artefacts on the deep fluids, we have found that in some segments, helium, methane and carbon dioxide are the main gas components that should originate from the deep Earth. The correlations among gas components are discussed and the fluid profiles in the hole are presented.
Accurate U‐Pb Age and Trace Element Determinations of Zircon by Laser Ablation‐Inductively Coupled Plasma‐Mass Spectrometry
Authors: Yuan Honglin , Gao Shan , Liu Xiaoming , Li Huiming , Günther Detlef , Wu Fuyuan
Published: May 2007

Various zircons of Proterozoic to Oligocene ages (1060‐31 Ma) were analysed by laser ablation‐inductively coupled plasma‐mass spectrometry. Calibration was performed using Harvard reference zircon 91500 or Australian National University reference zircon TEMORA 1 as external calibrant. The results agree with those obtained by SIMS within 2s error. Twenty‐four trace and rare earth elements (P, Ti, Cr, Y, Nb, fourteen REE, Hf, Ta, Pb, Th and U) were analysed on four fragments of zircon 91500. NIST SRM 610 was used as the reference material and 29Si was used as internal calibrant. Based on determinations of four fragments, this zircon shows significant intra‐and inter‐fragment variations in the range from 10% to 85% on a scale of 120 μm, with the variation of REE concentrations up to 38.7%, although the chondrite‐normalised REE distributions are very similar. In contrast, the determined age values for zircon 91500 agree with TIMS data and are homogeneous within 8.7 Ma (2s). A two‐stage ablation strategy was developed for optimising U‐Pb age determinations with satisfactory trace element and REE results. The first cycle of ablation was used to collect data for age determination only, which was followed by continuous ablation on the same spot to determine REE and trace element concentrations. Based on this procedure, it was possible to measure zircon ages as low as 30.37 0.39 Ma (MSWD = 1.4; 2s). Other examples for older zircons are also given.
A Preliminary Appraisal of Seven Natural Zircon Reference Materials for In Situ Hf Isotope Determination
Authors: Woodhead Jon D. , Hergt Janet M.
Published: May 2007

There is a growing need for new zircon reference materials for in situ Hf‐isotope analysis by laser ablation‐multicollector inductively coupled plasma‐mass spectrometry (LA‐MC‐ICP‐MS). In this contribution we document the results of a preliminary investigation of seven natural zircons, conducted in order to test their suitability in this regard. Solution MC‐ICP‐MS data on separated Lu and Hf fractions provided reference compositional data while the results of ca. 750 in situ LA‐MC‐ICP‐MS analyses allowed assessment of potential micrometre‐scale heterogeneity. On the basis of these analyses and additional relevant considerations such as availability, size and (Lu)Yb/Hf ratio, we suggest that, of the currently available zircons, Temora‐2 and Mud Tank are most likely to provide robust reference materials for Hf isotope determinations both at the present time and into the future. The former has the advantage of also being well‐characterised for U‐Th‐Pb systematics and suitable for in situ age determination, while the latter is the most readily available and is of very large grain size. Additional materials such as BR266, and 91500, although limited in supply, show more consistent Lu/Hf ratios and are thus of use in monitoring elemental fractionation during ICP‐MS analysis.
Speciation of Chromium in Artificially Contaminated Soil Reference Material GSJ JSO‐2 Using XANES and Chemical Extraction Methods
Authors: Tsuno Hiroshi , Ohta Atsuyuki , Kagi Hiroyuki , Imai Noboru , Tao Hiroaki , Nomura Masaharu
Published: May 2007

The oxidation states of chromium in GSJ JSO‐2 (artificially contaminated soil) and three other geochemical reference materials (GSJ JSO‐1, JLS‐1 and JMS‐1) were observed using X‐ray near edge structure (XANES). For comparison, other artificially contaminated soil materials (mimic‐JSO‐2) were prepared by adding Cr(VI) into JSO‐1. Their oxidation states of chromium were determined using XANES. The chromium contents were 1118 μg g‐1 for JSO‐2, 1352 μg g‐1 for mimic‐JSO‐2 and 69‐113 μg g‐1 for the other reference materials. Most chromium was present as hexavalent in mimic‐JSO‐2. No hexavalent species were detected in other samples. These results for chromium oxidation state in JSO‐2 and mimic‐JSO‐2 obtained with XANES resembled those obtained from a chemical extraction method. The present JSO‐2 has no trace of Cr(VI), although Cr(VI) was added as a major species during preparation. On the other hand, the content of Cr(VI) obtained in mimic‐JSO‐2 agreed with the original Cr(VI) content. A time‐elapse study showed that Cr(VI) contents in mimic‐JSO‐2 decreased gradually to 70% of the original abundance during 240‐day preservation in dry conditions. Moreover, the abundance of Cr(VI) decreased markedly to 15% after 240 days in the wet mimic‐JSO‐2 containing 20% m/m of water. These experiments suggested that soil humidity enhanced the reduction of Cr(VI) and that Cr(VI) was reduced even in dry conditions. Consequently, it is reasonable to infer that Cr(VI) doped into JSO‐2 was completely reduced to Cr(III) during the preservation period of 5 years. The certification of the long‐term stability of the chemical form in reference materials will be much more important in future.
Intracellular balance of oxidative stress and cytoprotective molecules in damaged interlobular bile ducts in autoimmune hepatitis and primary biliary cirrhosis: In situ detection of 8‐hydroxydeoxyguanosine and glutathione‐S‐transferase‐pi
Authors: Kadokawa Yoshiko , Ohba Kazuo , Omagari Katsuhisa , Akazawa Shiho , Hayashida Kenji , Ohnita Ken , Takeshima Fuminao , Mizuta Yohei , Kohno Shigeru
Published: May 2007

Aim:  Bile duct injury has been thought to be absent in autoimmune hepatitis (AIH), but recent studies have indicated that AIH patients do have bile duct injury. In this study, the intracellular balance of oxidative stress and cytoprotection in biliary epithelial cells was investigated to clarify the pathogenesis of bile duct injury in AIH.

Methods:  The intracellular status of oxidative DNA damage caused by oxidative stress and glutathione, an endogenous cytoprotective molecule, were examined in patients with AIH, primary biliary cirrhosis (PBC), and normal controls by immunostaining of 8‐hydroxydeoxyguanosine (8‐OHdG) and glutathione‐S‐transferase‐pi.

Results:  Immunohistochemically, 8‐OHdG expression was detected as abundantly in the damaged bile ducts of AIH patients as in PBC patients. Moreover, in AIH, 8‐OHdG expression was detected in damaged bile ducts more than in undamaged bile ducts. Glutathione‐S‐transferase‐pi expression was relatively preserved in the damaged bile ducts of AIH patients compared to PBC patients, reflecting preservation of intracellular glutathione.

Conclusions:  In AIH, oxidative stress and DNA damage may be involved in the pathogenesis of bile duct injury in a manner similar to that found in PBC. However, relatively preserved intracellular glutathione may play a key role in preventing progressive bile duct loss following bile duct injury in AIH.
Impact of Resistance Selection and Mutant Growth Fitness on the Relative Efficacies of Streptomycin and Levofloxacin for Plague Therapy
Authors: Louie Arnold , Deziel Mark R. , Liu Weiguo , Drusano George L.
Published: May 2007

Yersinia pestis
, the bacterium that causes plague, is a potential agent of biowarfare and bioterrorism. The aminoglycoside antibiotic streptomycin is the gold standard for treatment. However, this recommendation is based on scant animal and clinical data. We used an in vitro pharmacodynamic infection model to compare the efficacies of 10-day regimens of streptomycin versus the fluoroquinolone antibiotic levofloxacin for the treatment of
Y. pestis
infection and to evaluate for emergence of resistance. The human serum concentration-time profiles for standard clinical regimens of 1 g of streptomycin given every 12 h and 500 mg of levofloxacin given every 24 h were simulated. The growth fitness of drug-resistant mutants was examined in neutropenic and immunocompetent mouse thigh infection models. In the in vitro infection system, untreated bacteria grew from 10
7
to 10
10
CFU/ml. Streptomycin therapy caused a 10
5
CFU/ml reduction in the number of bacteria over 24 h, followed by regrowth with streptomycin-resistant mutants. Levofloxacin resulted in a 10
7
CFU/ml reduction in the number of bacteria within 12 h, ultimately sterilizing the culture without resistance selection. In both the normal and neutropenic mouse infection models, streptomycin-resistant and wild-type strains were equally fit. However, 90% of levofloxacin-resistant isolates, cultured from the control in vitro infection arm, did not proliferate in the mouse models. Thus, the fluoroquinolone antibiotic levofloxacin was superior to streptomycin in our in vitro infection model. The majority of levofloxacin-resistant mutants were less fit than streptomycin-resistant and wild-type
Y. pestis
.
Increased Expression ofampCinPseudomonas aeruginosaMutants Selected with Ciprofloxacin
Authors: Wolter Daniel J. , Schmidtke Amber J. , Hanson Nancy D. , Lister Philip D.
Published: May 2007

TwoPseudomonas aeruginosamutants exhibiting increased expression ofampCwere selected during exposure to ciprofloxacin. These mutants also exhibited significant increases inmexCD-oprJexpression, but further studies failed to show a link between the increased expression ofmexCD-oprJandampC. IncreasedampCexpression was not related to mutations withinampR, theampC-ampRintergenic region,ampD,ampDh2, orampDh3or to changes in the levels of expression of these amidase genes. However,ampDcomplementation restored wild-type levels ofampCexpression and ceftazidime susceptibility, suggesting alternative mechanisms ofampCregulation.
Novel Complex Class 1 Integron Bearing an IS
CR1
Element in an
Escherichia coli
Isolate Carrying the
bla
CTX-M-14
Gene
Authors: Bae Il Kwon , Lee You-Nae , Lee Wee Gyo , Lee Sang Hee , Jeong Seok Hoon
Published: May 2007

This work identifies an IS
CR1
-related
bla
CTX-M-14
gene, which has never been reported before, from a clinical isolate of
Escherichia coli
. The
bla
CTX-M-14
gene was preceded by an IS
CR1
element that was followed by a class 1 integron containing three different insert gene cassettes, i.e.,
dfrA12
,
orfF
, and
aadA2
.
Early Bactericidal Activity of High-Dose Rifampin in Patients with Pulmonary Tuberculosis Evidenced by Positive Sputum Smears
Authors: Diacon A. H. , Patientia R. F. , Venter A. , van Helden P. D. , Smith P. J. , McIlleron H. , Maritz J. S. , Donald P. R.
Published: May 2007

We studied the early bactericidal activity of twice the standard dose of rifampin in subjects with pulmonary tuberculosis evidenced by positive smears. The observed mean 2-day activity was almost double that reported at the standard dose. Further studies are warranted to establish whether higher rifampin doses might assist in shortening tuberculosis treatment.
High-Affinity, Human Antibody-Like Antibody Fragment (Single-Chain Variable Fragment) Neutralizing the Lethal Factor (LF) of
Bacillus anthracis
by Inhibiting Protective Antigen-LF Complex Formation
Authors: Pelat Thibaut , Hust Michael , Laffly Emmanuelle , Condemine Florence , Bottex Chantal , Vidal Dominique , Lefranc Marie-Paule , Dübel Stefan , Thullier Philippe
Published: May 2007

The anthrax lethal toxin (LT) consists of two subunits, the protective antigen (PA) and the lethal factor (LF), and is essential for anthrax pathogenesis. Several recombinant antibodies directed against PA and intended for medical use have been obtained, but none against LF, despite the recommendations of anthrax experts. Here we describe an anti-LF single-chain variable fragment (scFv) that originated from an immunized macaque (
Macaca fascicularis
) and was obtained by phage display. Panning of the library of 1.8 × 10
8
clones allowed the isolation of 2LF, a high-affinity (equilibrium dissociation constant, 1.02 nM) scFv, which is highly neutralizing in the standardized in vitro assay (50% inhibitory concentration, 1.20 ± 0.06 nM) and in an in vivo assay. The scFv neutralizes anthrax LT by inhibiting the formation of the LF-PA complex. The genes encoding 2LF are very similar to those of human immunoglobulin germ line genes, sharing substantial (84.2%) identity with their most similar, germinally encoded counterparts; this feature favors medical applications. These results, and others formerly published, demonstrate that our approach can generate antibody fragments suitable for prophylaxis and therapeutics.
In Vitro Activities of 15 Antimicrobial Agents against 110 Toxigenic
Clostridium difficile
Clinical Isolates Collected from 1983 to 2004
Authors: Hecht David W. , Galang Minerva A. , Sambol Susan P. , Osmolski James R. , Johnson Stuart , Gerding Dale N.
Published: May 2007

The incidence and severity of
Clostridium difficile
-associated disease (CDAD) is increasing, and standard treatment is not always effective. Therefore, more-effective antimicrobial agents and treatment strategies are needed. We used the agar dilution method to determine the in vitro susceptibility of the following antimicrobials against 110 toxigenic clinical isolates of
C. difficile
from 1983 to 2004, primarily from the United States: doripenem, meropenem, gatifloxacin, levofloxacin, moxifloxacin, OPT-80, ramoplanin, rifalazil, rifaximin, nitazoxanide, tizoxanide, tigecycline, vancomycin, tinidazole, and metronidazole. Included among the isolates tested were six strains of the toxinotype III, NAP1/BI/027 group implicated in recent U.S., Canadian, and European outbreaks. The most active agents in vitro were rifaximin, rifalazil, tizoxanide, nitazoxanide, and OPT-80 with MICs at which 50% of the isolates are inhibited (MIC
50
) and MIC
90
values of 0.0075 and 0.015 μg/ml, 0.0075 and 0.03 μg/ml, 0.06 and 0.125 μg/ml, 0.06 and 0.125 μg/ml, 0.125 and 0.125 μg/ml, respectively. However, for three isolates the rifalazil and rifaximin MICs were very high (MIC of >256 μg/ml). Ramoplanin, vancomycin, doripenem, and meropenem were also very active in vitro with narrow MIC
50
and MIC
90
ranges. None of the isolates were resistant to metronidazole, the only agent for which there are breakpoints, with tinidazole showing nearly identical results. These in vitro susceptibility results are encouraging and support continued evaluation of selected antimicrobials in clinical trials of treatment for CDAD.
The
Pseudomonas aeruginosa
LasB Metalloproteinase Regulates the Human Urokinase-Type Plasminogen Activator Receptor through Domain-Specific Endoproteolysis
Authors: Leduc Dominique , Beaufort Nathalie , de Bentzmann Sophie , Rousselle Jean-Claude , Namane Abdelkader , Chignard Michel , Pidard Dominique
Published: May 2007

Pseudomonas aeruginosa
is an opportunistic pathogen in human lungs, where its secretable LasB metalloproteinase can be a virulence factor. The urokinase-type plasminogen activator receptor (uPAR) participates in pericellular proteolysis and the adherence/migration of epithelial cells and leukocytes recruited during infection and shows functional regulation by various proteinases via limited endoproteolysis occurring within its three domains (D1 to D3). We thus examined the proteolytic activity of LasB on uPAR by using recombinant uPAR as well as uPAR-expressing, human monocytic, and bronchial epithelial cell lines. Protein immunoblotting and flow immunocytometry using a panel of domain-specific anti-uPAR antibodies showed that LasB is able to cleave uPAR both within the sequence linking D1 to D2 and at the carboxy terminus of D3. Comparison of LasB-producing and LasB-deficient bacterial strains indicated that LasB is entirely responsible for the uPAR cleavage ability of
P. aeruginosa
. Based on amino-terminal protein microsequencing and mass spectrometry analysis of the cleavage of peptides mimicking the uPAR sequences targeted by LasB, cleavage sites were determined to be Ala
84
-Val
85
and Thr
86
-Tyr
87
(D1-D2) and Gln
279
-Tyr
280
(D3). Such a dual cleavage of uPAR led to the removal of amino-terminal D1, the generation of a truncated D2D3 species, and the shedding of D2D3 from cells. This proteolytic processing of uPAR was found to (i) drastically reduce the capacity of cells to bind urokinase and (ii) abrogate the interaction between uPAR and the matrix adhesive protein vitronectin. The LasB proteinase is thus endowed with a high potential for the alteration of uPAR expression and functioning on inflammatory cells during infections by
P. aeruginosa
.
Human Lung Innate Immune Response toBacillus anthracisSpore Infection
Authors: Chakrabarty Kaushik , Wu Wenxin , Booth J. Leland , Duggan Elizabeth S. , Nagle Nancy N. , Coggeshall K. Mark , Metcalf Jordan P.
Published: May 2007

Bacillus anthracis, the causative agent of inhalational anthrax, enters a host through the pulmonary system before dissemination. We have previously shown that human alveolar macrophages participate in the initial innate immune response toB. anthracisspores through cell signal-mediated cytokine release. We proposed that the lung epithelia also participate in the innate immune response to this pathogen, and we have developed a human lung slice model to study this process. Exposure of our model toB. anthracis(Sterne) spores rapidly activated the mitogen-activated protein kinase signaling pathways ERK, p38, and JNK. In addition, an RNase protection assay showed induction of mRNA of several cytokines and chemokines. This finding was reflected at the translational level by protein peak increases of 3-, 25-, 9-, 34-, and 5-fold for interleukin-6 (IL-6), tumor necrosis factor alpha, IL-8, macrophage inflammatory protein 1α/β, and monocyte chemoattractant protein 1, respectively, as determined by an enzyme-linked immunosorbent assay. Inhibition of individual pathways by UO126, SP600125, and SB0203580 decreased induction of chemokines and cytokines by spores, but this depended on the pathways inhibited and the cytokines and chemokines induced. Combining all three inhibitors reduced induction of all cytokines and chemokines tested to background levels. An immunohistochemistry analysis of IL-6 and IL-8 revealed that alveolar epithelial cells and macrophages and a few interstitial cells are the source of the cytokines and chemokines. Taken together, these data showed the activation of the pulmonary epithelium in response toB. anthracisspore exposure. Thus, the lung epithelia actively participate in the innate immune response toB. anthracisinfection through cell signal-mediated elaboration of cytokines and chemokines.
Helicobacter pyloriChemotaxis Modulates Inflammation and Bacterium-Gastric Epithelium Interactions in Infected Mice
Authors: Williams Susan M. , Chen Yu-Ting , Andermann Tessa M. , Carter J. Elliot , McGee David J. , Ottemann Karen M.
Published: May 2007

The ulcer-causing pathogenHelicobacter pyloriuses directed motility, or chemotaxis, to both colonize the stomach and promote disease development. Previous work showed that mutants lacking the TlpB chemoreceptor, one of the receptors predicted to drive chemotaxis, led to less inflammation in the gerbil stomach than did the wild type. Here we expanded these findings and examined the effects on inflammation of completely nonchemotactic mutants and mutants lacking each chemoreceptor. Of note, all mutants colonized mice to the same levels as did wild-typeH. pylori. Infection by completely nonchemotactic mutants (cheWorcheY) resulted in significantly less inflammation after both 3 and 6 months of infection. Mutants lacking either the TlpA or TlpBH. pylorichemotaxis receptors also had alterations in inflammation severity, while mutants lacking either of the other two chemoreceptors (TlpC and HylB) behaved like the wild type. Fully nonchemotactic and chemoreceptor mutants adhered to cultured gastric epithelial cells and caused cellular release of the chemokine interleukin-8 in vitro similar to the release caused by the wild type. The situation appeared to be different in the stomach. Using silver-stained histological sections, we found that nonchemotacticcheYorcheWmutants were less likely than the wild type to be intimately associated with the cells of the gastric mucosa, although there was not a strict correlation between intimate association and inflammation. Because others have shown that in vivo adherence promotes inflammation, we propose a model in whichH. pyloriuses chemotaxis to guide it to a productive interaction with the stomach epithelium.