Delta-aminolevulinic acid dehydratase (ALA-d), an enzyme in the heme biosynthetic pathway is extremely sensitive to inhibition by lead (Pb). I evaluated the erythrocyte ALA-d activity ratio (the ratio between the fully restored enzyme activity and that measured without removing any inhibitory influence that might be present) as an indicator of Pb exposure ...

Comparison of results from the isotope dilution and the single-grain zircon evaporation methods on highly discordant samples shows that the evaporation method can yield accurate crystallization ages on some zircon populations that display complex discordant patterns. Three granite gneiss samples from the Western Gneiss Region, Norway, which crystallized at approximately 1660 ...

Workshop on Data Handling in LA-ICP-MS U-Th-Pb Geochronology; San Francisco, California, 12-13 December 2009; The use of uranium-thorium-lead (U-Th-Pb) laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) geochronology involves rapid analysis of U-and Th-rich accessory minerals. It routinely achieves 1-2% precision for ...

ICP-MS analysis permits rapid and precise dating of minerals with high U and Th contents. Here we describe a new method for in situ determination of 206Pb/238U, 207Pb/^{235}U, ^{208}Pb/232Th, and 207Pb/206Pb ages in monazite via laser ablation (New Wave Research UP-213 laser system), ...

Analyses of binary Pb- Cu, Pb- Sn, Zn- Cd, and Pb- PbO indicated a direct proportion between the reflected BETA intensity and the content of heavy metal. Such an analysis may be carried out within a few minutes with an error of less than 1%; for Pb- ...

Baddeleyite has significant potential for U-Pb geochronology of mafic rocks, but due to small crystal sizes it can be exceedingly difficult to extract by conventional mineral separation techniques. We therefore developed in-situ dating of baddeleyite crystals with lateral dimensions between 5 and 20 ?m (micro-baddeleyite) in polished petrographic thin sections using a CAMECA ...

Multicollector ICP-MS is a mainstream method for precise isotopic analyses of large (over 10-8 g) quantities of Pb, and is becoming increasingly popular for very rapid, even if relatively imprecise, U-Pb dating of U-bearing minerals using laser ablation. At the same time, high precision U-Pb geo- and cosmo- ...

Recent advances highlighted are the analysis of tiny quantities of U and Pb isotopes, ID-TIMS U-Pb dating using EARTHTIME double spike tracers and improved detectors, and the performance of integrated LA-MC- ICP-MS systems for U-Pb dating. Detector improvements: The use of 1012 ohm resistors with faraday detectors has shown that their ...

Uncertainty in U-Pb geochronology results from a wide variety of factors, including isotope ratio determinations, common Pb corrections, initial daughter product disequilibria, instrumental mass fractionation, isotopic tracer calibration, and U decay constants and isotopic composition. The relative contribution of each depends on the proportion of ...

The multistep shell-model method is used to analyse the multiplet structure of 205Pb and 203Pb in terms of single-hole states (207Pb) coupled to two- (206Pb) and four- (204Pb) hole excitations, respectively. It is found that at least one member of a given multiplet is ...

This report presents the locations, descriptions, analytical procedures used, and an inter-lab comparison of over 1100 geochemical analyses of samples of soil and sediment in and downstream of a major lead-zinc-silver mining district in the Coeur d'Alene (CdA) drainage basin of northern Idaho. The samples fall in 3 broad categories: (1) samples from vertical profiles of ...

Solution equilibria in the PbSO 4 -H 2 SO 4 -H 2 O and PbSO 4 -Na 2 SO 4 -H 2 O systems have been modelled using the Pitzer formalism for the determination of activity coefficients over the temperature range from 0-60�C, and up to 6 m in H 2 SO 4 . The available literature, common ion solubility data, and our own experimental data at 60�C have been ...

fission cross section for the 2?sPb projectile of 315 mb shown in table ... fission cross section of 380 rob. However, with our more accurate ...

Monazite (mnz) geochronology is rapidly becoming the technique of choice for unraveling local and regional polyphase thermotectonic histories. High retention for radiogenic Pb makes monazite ideal for various in-situ radiometric dating methods including techniques such as electron microprobe (EMP) and ion microprobe (IMP, especially SHRIMP). Recent studies have shown the ...

Numerous areas have been contaminated by heavy metals and metalloids due to industrial and mining activities. Studies investigating the behavior of such contaminants in the environment have identified speciation as a key factor controlling their mobility, availability and toxicity. Here we characterize As- and Pb-bearing phases resulting from the oxidation of sulfide-rich ...

In recent years, MC-ICP-MS has become a powerful tool to measure Pb isotopes with high precision and accuracy. Yet, this technique is still relatively new, and the complexities related to using an ICP ion source for high precision isotope measurements are only now becoming apparent. In addition, most analytical development work so far has focussed on synthetic solutions and ...

Apatite is a common U-bearing accessory mineral in magmatic, sedimentary, and metamorphic rocks, with a U-Pb closure temperature of 450-550�C, making U-Pb dating of apatite a potentially valuable thermochronometer. However, the low U concentration in apatite and its tendency to incorporate high amounts of common lead has previously limited the accuracy ...

A number of U-Pb geochronological techniques are now available, each of which has pros and cons associated with spatial resolution, accuracy, precision and also operating cost and throughput. Zircon U-Pb age analyses using TIMS (Thermal Ionization Mass Spectrometry) can yield geological dates with uncertainties at or below the 1 permil ...

Accessory phase minerals with inherited cores surrounded by very thin (often <10?m) and irregular rims are common throughout the geologic record. Current in-situ U-Th-Pb analytical techniques (e.g. SIMS, LA-ICPMS) generally employ a static 'spot' analysis method which makes it difficult to confidently sample only the outer rim of such material. In addition, this approach ...

High-precision IDTIMS U-Pb zircon dates provide the most precise and accurate isotopic benchmarks in absolute time, due to the concordancy check of the paired U-Pb decay schemes, the precisely measured 235U and 238U decay constants, very high initial parent/daughter ratios, and the robust nature of zircon to loss or gain of U and ...

Methods are presented for in situ determination of Pb/U, Pb/Th, and Pb/Pb ages in monazite by laser ablation, single-collector, magnetic sector inductively coupled plasma-mass spectrometry (ICP-MS). Analytical precisions for individual spot analyses are +/-2-3% for 206Pb/238U and ...

U-Pb baddeleyite geochronology has become a major tool for dating mafic rocks, especially dikes associated with Large Igneous Provinces. However, in many cases, post-crystallization Pb-loss and intergrowth of baddeleyite and zircon limit the precision and/or accuracy of crystallization ages. We present results from multi-step digestion experiments designed ...

Using appropriate clean methods for handling and preparation, 57 ice samples from the Devon Island Ice Cap, representing the period 134 to 15,800 years before present (BP), were analyzed for Pb, Sc, and Pb isotopes (206Pb, 207Pb, 208Pb) using ICP-SMS. The greatest Pb ...

Jan 7, 2003 ... Dataset Title: SHRIMP U-Th-Pb Analyses of Titanite. Dataset Release Date: January 2001. Dataset Publisher: Geological Society of America ...

U-Pb-Th Analyses of Titanite from the Western Alps Entry ID: GEOLOGY_2001005. [ View Full Record ]. [ Update this Record ]. Updating this record requires ...

BackgroundPrevious work has demonstrated the potential for peripheral blood (PB) gene expression profiling for the detection of disease or environmental exposures.Methods and FindingsWe have sought to determine the impact of several variables on the PB gene expression profile of an environmental exposure, ionizing radiation, and to determine the ...

Analyses of Pb concentration and Pb isotope ratios were performed on leached and residual fractions of 143 surface sediment samples and 2 radiometrically dated box-core sediment samples collected from shelf (77), coastal (22) and estuarine (46) environments of the Yellow Sea. Eight suspended sediment samples were collected from the ...

Advances in microanalytical techniques continue to revolutionize trace element and isotope geochemistry. Yet the lack of widely available geological reference materials has made interlaboratory comparisons and assessment of analytical accuracy difficult or impossible in many cases. The preparation and extensive analysis of the MPI-DING glasses has been designed to fill this gap. Here we report ...

The energies of high-spin states formed by adding a few valence nucleons to /sup 208/Pb can be accurately calculated by using empirical interaction matrix elements. It is shown that the energies of high-spin states with /sup 207/Pb, /sup 206/Pb, and /sup 204/Pb as the core can also be ...

The production at central rapidity of K0S, ?, ? and ? particles in Pb Pb collisions at 158 A GeV/c has been measured by the NA57 experiment over a centrality range corresponding to the most central 53% of the inelastic Pb Pb cross section. In this paper we present the rapidity distribution of each particle in the ...

The reactions 204Pb(d, t), 204Pb(d, p), 204Pb(d, d') and 204Pb(t, p) were investigated at incident energies of 12-13 MeV, the reaction products being momentum analysed in a multi-angle, magnetic spectrograph. Seven excited states were observed in 203Pb up to 2.8 MeV ...

More accurate duta relating to the short period gamma radiation emitted from thallium irradiated by 19.2-Mev protons and 14.7-Mev neutrons are presented. It is demonstrated that the radiation is from the Pb/sup 205//sup m/ isomer. The cross sections for production of Pb/sup 205//sup m/ nuclei in proton and neutron reactions ...

Accurate prediction of future climate scenarios is contingent on our understanding of past and present climate mechanisms. This is done in part through the reconstruction of historical climate changes using proxy records from terrestrial and marine archives. Terrestrial archives covering the Holocene and late Pleistocene are limited, most acutely in the Southern Hemisphere. ...

Several physicochemical analyses are being performed to better characterize the Devonian gas shales located in the Appalachian and Illinois Basins. The results of these analyses are being integrated with the geochemical analyses to present an accurate cha...

Development of Pb pollution histories using tree ring analyses has been troubled by possible mobility of Pb within stem xylem. In a 2-yr study, we exposed red spruce (Picea rubens Sarg.) seedlings to Pb during one growing season, with Pb excluded in either the previous or following growing ...

The analytical sensitivity, precision, and accuracy of trace metal (Pb, Cd, Cr, Cu, Fe, and Mn) analyses on aqueous samples performed at ORNL using a flameless graphite furnace atomic absorption system were evaluated in comparison to analyses performed by three independent laboratories using similar systems. All laboratories analyzed ...

Trends and sources of lead aerosol pollution in the North Pacific boundary layer from 1970-2001 are investigated using a high-resolution ice core record recovered from Eclipse Icefield (3017 masl; St. Elias Mountains, Canada). Average Pb concentrations in the ice core are enriched 31.8 times above crustal values based on ratios with five crustal reference elements (La, Ce, Pr, ...

Allanite has great potential as a chronometer for geological processes, offering the potential to link physico-chemical conditions, based on petrological observations, and robust in-situ U-Th-Pb dating. Despite advances in in-situ U-Th-Pb dating of this important mineral, a number of analytical challenges remain unresolved. Three critical issues have been ...

Urban soils are commonly contaminated with Pb from multiple sources. Total Pb levels commonly exceed 500 mg/kg in center city soils, ranging to above 10,000 where paint residue was incorporated in soils. Many persons seek to grow garden crops in cities, but obtaining useful soil analyses needed to p...

-Pb Laser Ablation ICP-MS Zircon Dating using Matrix-Matched Calibration Samples with a Frequency Quadrupled of laser ablation (LA) ICP-MS to the in situ analysis of 207Pb/206Pb and 206Pb/238U isotopic ratios analyses, LA-ICP-MS results on reference materials (UQ-Z1 and G91500) indicated ...

The SHRIMP analyses have been conducted for rock samples from the Koongarra secondary ore deposit to obtain activity ratios of (sup 234)U/(sup 238)U and isotopic ratios of (sup 207)Pb/(sup 206)Pb and (sup 204)Pb/(sup 206)Pb. Target minerals for the analys...

The timing and extent of early continental crust formation and mantle differentiation remain contentious issues in Earth Sciences. Here we report new, SHRIMP U-Pb zircon geochronology (n = 142 spot analyses on 69 grains), combined with LA-MC-ICPMS 176Hf determinations (n = 110 spot analyses on 59 grains), in three well-characterized ...

The Old Lead Belt of Missouri was a major lead-producing region for over a century. Several large tailings piles and other industrial wastes remain behind, though mining operations in the region ceased in 1972. Samples of stream sediments and fish were collected from established sites on the Big River and Flat River Creek over a 3-year period from 1998 to 2000 to evaluate ongoing remediation ...

Chromosome abnormalities are common in oocytes derived from patients undergoing IVF treatment. The proportion of oocytes displaying aneuploidy is closely related to maternal age and may exceed 60% in patients over 40 years old. However, little information currently exists concerning the incidence of such anomalies in oocytes derived from young fertile women. A total of 121 metaphase II oocytes and ...

There is growing evidence that the budget of Pb in mantle peridotites is largely contained in sulfide, and that Pb partitions strongly into sulfide relative to silicate melt. In addition, there is evidence to suggest that diffusion rates of Pb in sulfide (solid or melt) are very fast. Given the possibility that sulfide melt �wets� ...

U-Pb systematics were determined from fifteen phosphate separates from equilibrated ordinary chondrites and from small bulk fragments of the same meteorites. The high U-238/Pb-204 ratios of thirteen of these phosphate separates lead to extremely radiogenic Pb whose Pb-206/Pb-204 ratios range ...

This analysis undertook the task of designing and implementing a methodology to determine an individual's probabilistic radiation dose from ingestion of foods utilizing Crystal Ball. A dietary intake model was determined by comparing previous existing models. Two principal radionuclides were considered-Lead210 (Pb-210) and Radium 226 (Ra-226). Samples from three different ...

Over the past two decades, U-Pb geochronology by ID-TIMS has been refined to achieve internal (analytical) uncertainties on a single grain analysis of � ~ 0.1-0.2%, and 0.05% or better on weighted mean dates. This level of precision enables unprecedented evaluation of the rates and durations of geological processes, from magma chamber evolution to mass extinctions and ...

The lipid content and composition of four strains of Paracoccidioides brasiliensis were analysed to determine any possible correlation with their virulence for hamsters and mice. Two strains, Pb168 and Pb141, were equal in virulence, Pb9 was slightly virulent and Pb140 was avirulent under the ...

Several studies have shown that MORB from the Indian Ocean have different isotopic characteristics compared to those from the Pacific or Atlantic Oceans. A particular Pb isotope feature of Indian Ocean MORB is their high 208Pb/204Pb ratio compared to those from the Pacific or North Atlantic. These isotope differences have been ...

Lead dioxide (PbO(2)), a new form of lead corrosion product discovered in the distribution system, is formed via the chlorination of Pb(II) solids and plays an important role in regulating lead concentration in drinking water. The kinetics of its formation, however, has not been quantitatively determined primarily because of the difficulties in ...

We highlight the most recent top quark properties measurements performed at the Tevatron collider by the CDF and D0 experiments. The data samples used for the analyses discussed correspond to an integrated luminosity varying from 360 pb{sup -1} to 760 pb{sup -1}.

Measurements of {psi} and {psi}{prime} production at the CERN SPS are compared to predictions based on a hadronic model of charmonium suppression. Detailed information is presented to facilitate comparison to other analyses. Sensitivity of these conclusions to model parameters is discussed.

Measurements of (psi) and (psi)(prime) production at the CERN SPS are compared to predictions based on a hadronic model of charmonium suppression. Detailed information is presented to facilitate comparison to other analyses. Sensitivity of these conclusio...

A new U-Pb zircon dating protocol for small (10�50 ?m) zircons has been developed using an automated searching method to locate zircon grains in a polished rock mount. The scanning electron microscope-energy-dispersive X ray spectrum-based automated searching method can routinely find in situ zircon grains larger than 5 ?m across. A selection of these grains was ablated ...

The roles of simultaneous (one-step) and sequential (two-step) transfer processes in the reaction exp 208 Pb(p, t) exp 206 Pb(3 exp + , 1.34 MeV.) are investigated. Both processes are accurately evaluated employing realistic wave functions and finite-rang...

The identification and retrieval of a large population of ancient zircons (>4 Ga; Hadean) is of utmost priority if models of the early evolution of Earth are to be rigorously tested. We have developed a rapid and accurate U-Pb zircon age determination protocol utilizing a fully automated multi-collector ion microprobe, the ANU SHRIMP II, to screen and ...

The relation between lead in air (PbA) and lead in blood (PbB), concentrations was investigated among 44 workers in five major operations in a United States high volume, lead acid battery plant. The study covered a 30 month period in which workers received frequent PbA and PbB determinations, workers remained in a ...

Residents in older homes may experience increased lead (Pb) exposures due to release of lead from interior paints manufactured in past decades, especially pre-1960s. The objective of the study was to determine the speciation of Pb in settled dust from an urban home built during WWII. X-ray absorption near-edge structure (XANES) and micro-X-ray diffraction ...

The Pb isotopic compositions of galenas from volcanogenic massive sulfide (VMS) deposits have been used widely in the past to track terrestrial Pb evolution for several important reasons. First, the galenas in the VMS ores have U/Pb=0, which lock in their Pb isotopic compsitions at the time of their formation. ...

Forty-two elements in four standard reference materials and oyster and cockle tissue were analysed by the X-ray fluorescence spectrometry (XRF) method. Comparisons between certified values for standard reference materials and those of the authors indicate that XRF is suitable for determining Ba, Br, Cu, Fe, Mn, Pb, Rb, Sr, and Zn in organic matrix. Results ...

An investigation show that the temperature-induced band gap (Eg) variation of PbSe nanocrystals is strongly sizedependent. The temperature coefficients (dEg/dT) evolve from negative to zero and then to positive values, with the increase of PbSe nanocrystal sizes. Such phenomena imply that PbSe nanocrystals may be the potential ...

The release of small gaseous molecules is a general phenomenon of irradiated polymers. Polyethylene (PE), polypropylene (PP) and polybutene (PB) were irradiated with ions of different electronic stopping power. We show that the gas emission can provide important information on the damage process if a reliable chemical identification of the molecules released and ...

In this study, coupled Pb concentration/Pb isotope data were used to evaluate the effect of a shooting range (operational for over 30 years) on Pb contamination of adjacent agricultural soils and the associated environmental risks. Lead was mainly concentrated in the arable layer of the contaminated agricultural soils at total ...

A method for the determination of Pb isotope ratios (IR) in cigarette tobacco by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) has been developed and applied to tobacco samples from genuine and counterfeit cigarettes obtained in the USA. The IR �??Pb/�??Pb, (208)Pb/�??Pb, �??Pb/�??Pb, ...

Elevated Pb levels in humans through environmental exposure are a significant health concern requiring scientific study of the sources of, and physiological response to this toxin. This requires a simple and precise method for measuring radiogenic Pb isotopes and Pb levels in blood. Presented here is a combination of methods for ...

Lead (Pb) contamination is a nationwide public health problem which is prevalent among children in urban metropolitan areas. The source of Pb contamination is due mostly to emissions from vehicular traffic using leaded gasoline. Pb alkyl species used by automobile-related industries include tetraethyl Pb (TEL), ...

U-Pb zircon geochronology, pioneered by Tom Krogh, is a cornerstone for the calibration of the time scale. Before Krogh's innovations, U-Pb geochronology was essentially limited by laboratory blank Pb (typically hundreds of nanograms) inherent in the then existing zircon dissolution and purification methods. The introduction of high ...

It is widely recognized that lead (Pb) affects children's cognitive function, even at relatively low blood lead levels (<10 �g dL(-1)). The determination of the source of Pb in children is essential for effective risk management. The use of multi-collector ICPMS (MC-ICPMS) for isotope ratio measurements of Pb in environmental and ...

The analysis of Hf isotopes in zircon by LA-MC-ICPMS is a promising new analytical method that is increasingly being used by many laboratories. The total uncertainty of these laser Hf isotopic analyses, however, has several potential components that should be fully accounted for in assigning total analytical uncertainty. Currently, this full respresentation of uncertainty is ...

Thermal analyses of the systems KF-- beta PbF/sub 2/ and ZnF/sub 2/- beta PbF/sub 2/ are reported. The former system has a eutectic at 465 deg C and 33.3 mole% PbF/sub 2/, the latter has a eutectic at 590 deg C and about 60 mole% PbF/sub 2/. No compound formation was detected in ...

A rapid determination method of (87)Sr/(86)Sr and Pb isotope ((204)Pb, (206)Pb, (207)Pb, and (208)Pb) ratios was applied to determining the geographic origin of grain crops. This new method is more economical in terms of both time and cost compared to conventional methods. We used samples of ...

OBJECTIVE: Blood lead (B-Pb), one of the most used toxicological biomarker all kind, has serious limitations. Thus, the objective is to evaluate whether plasma lead (P-Pb) is more adequate. METHODS: A long-term follow-up study of five cases of lead poisoning. P-Pb was analysed by inductively coupled plasma mass ...

The results of U-Pb isotope analyses on a silicate inclusion from the Kodaikanal iron meteorite, which contains evidence of intensive chemical activity occurring about 800 Myr after the formation of the solar system, are reported. Leaching experiments on the two major phases, clinopyroxene and alkali-rich glass, indicate a contamination by terrestrial ...

Elevated lead (Pb) concentrations in residential houseyards around house walls painted with Pb-based pigments pose serious human health risks, especially to children. Vetiver grass (Vetiveria zizanioides L.) has shown promise for use in in situ Pb phytoremediation efforts. However, little is known about the biochemical mechanisms ...

The KaraBogazGol (KBG) water level oscillations were reconstructed in the last 200 years using the geochemical evolution of the uppermost meter of its sedimentary infill. High-resolution studies of the mineralogical composition of the KBG sediments show alternating periods of high concentration brines followed by periods of more dilute waters. The relative water level reconstruction was based on ...

U-Pb-Th Analyses of Titanite from the Western Alps [GEOLOGY_2001005] [Adapted from "About the GSA Data Repository", ...

SHRIMP U-Pb analyses of zircon from 11 samples of igneous and ... Data were collected on SHRIMP I and SHIRIMP II at the Research School ...

... the end of the experiment stable lead was analysed by atomic absorption spectrometry ... five consecutive days with 5 mg Pb/kg body weight per day ...

... Sedimentary analyses examined spatial and temporal patterns, and included grain size, geochronology ( 7 Be, 210 Pb) and x-radiography ...

... and semivolatile organics and metals with separate analyses for AS, HG, DBCP, hydrazines, and nitrosamines. MIBK, DLDRN, CD, CR, CU, PB, ZN ...

Samples were collected under sterile methods and analysed for trace metals components such as Pb, Cu, Zn, Cd, Ni, Fe, Cr, Mn and As, using the 'totally ...

... Trapped specimens of fishes and crabs were analyzed for body burdens of Hg, Cd, Pb, Cu, and Zn; the results of the analyses are presented in ...

Uranium lead ratios (commonly represented as 238U/204Pb = ?) calculated for the sources of martian basalts preserve a record of petrogenetic processes that were active during early planetary differentiation and formation of martian geochemical reservoirs. To better define the range of ? values represented by the source regions of martian basalts, we completed U ...

The ability to conduct multi-isotopic analyses (e.g., Sr-Nd-Hf-Pb) on the same sample is critical for studies that evaluate the mantle source components of oceanic basalts. The isotopic compositions of relatively immobile elements, such as Nd (and other REE) and Hf, are considered to be relatively resistant to alteration, however, ...

Physicochemical analyses of polluted soils are limited in their ability to determine all hazardous compounds, their bioavailability, and their combined effects on living organisms. Bioassays, on the other hand, can evaluate environmental quality more accurately. This study assesses the genotoxic potential of water extracts from soil polluted with metals ...

The 202Pb-205Pb-233U-235U spike (Pb DS), prepared at the Geological Survey of Canada in 2005 [1], and the 202Pb-205Pb-235U spike, prepared at the Department of Geosciences, University of Oslo [2], have been used for more than two years. Both spikes are routinely used for TIMS analysis of ...

Isotope dilution Ar analyses are reported for all samples originally analysed by neutron activation. The methods are in agreement but the more precise and accurate isotope dilution analyses are preferred.

We constructed models of umbilical cord blood lead (PbB), with and without the addition of maternal PbB at delivery and earlier in pregnancy, to determine which factors explaining cord PbB depended upon maternal PbB and which did not. We prospectively studied women of low-to-middle socioeconomic status who lived in ...

Atmospheric Pb contamination was studied using snow and ice from the Canadian arctic. Forty-five samples representing the past ten years of snow accumulation on Devon Island contain an average of 45.2 pg/g of Pb but only 0.43 pg/g of Sc. The average ratio of Pb to Sc (105) is far greater than that of soil-derived dust particles (in the ...

A 140 m snow/ice core drilled at Mont Blanc, France, has been analysed for Pb isotopes, Pb and Ba concentrations. The 206Pb/207Pb ratio, which was measured by thermal ionisation mass spectrometry, decreased steadily from ~1.18 about two centuries ago to ~1.17 in 1960, then fell rapidly to ~1.15 ...

Results are presented for a study of spatial distributions and temporal trends in concentrations of lead (Pb) from different sources in soil and vegetation of an arable farm in central Scotland in the decade since the use of leaded petrol was terminated. Isotopic analyses revealed that in all of the samples analysed, the ...

Understanding of the environmental behavior of Ra is important from the viewpoint of the long-termed repository safety of radioactive waste, but investigation of Ra behavior in natural environment is difficult to detect. We found isotopic evidence of Ra transportation and its selective uptake into clay minerals from Pb isotopic analyses. Illite grains ...

The liquidus surface of the ternary reciprocal system PbTe + CdS in equilibrium PbS + CdTe was constructed and the interaction in the system PbTe-CdS was studied with the help of the differential-thermal and microstructural analyses and mathematical planning of the experiment. It was shown that the constitution ...

Structural models obtained using classical molecular dynamics (MD) simulations and realistic interatomic potentials for solid metals are tested using experimental results obtained by x-ray absorption spectroscopy (XAS). Accurate L-edge extended x-ray absorption fine-structure (EXAFS) measurements of Pb grains dispersed in BN and graphite matrices have been ...

The requirement of highly accurate analyses for isentropic trajectory calculations established the need for the authors to revise the most recent approaches to generating objective analyses on isentropic surfaces. Two factors which contributed to generati...

The mapping methods consist of: (1) deterministic structural analyses with fine (convergent) finite element meshes, (2) probabilistic structural analyses ...

A technique has been developed and tested to analyse 207Pb/206Pb apparent ages by thermal evaporation of radiogenic lead directly from untreated whole zircon grains (?0.3 mm). The evaporation analyses are performed in the double-filament arrangement of a thermal ion mass spectrometer (ThIMS). The method is a ...

The techniques to measure lead isotopic abundances in geologic material have been refined and tested with National Bureau of Standards lead isotope standards. The results from 28 analyses show that our measurements of exp 207 Pb/ exp 206 Pb and exp 208 Pb...

The nuclear technics 'PIXE' and 'XRF', were used for heavy metals analysis (Fe, Cu, Zn, Pb, and Hg), in sword fish (xiphias Gladius) caught in Ghazaouet bay. Muscles, liver and gonads were analysed. The methods gave similar results. A bioaccumulation phen...

We have analysed Pb isotopes in natural rutile crystals by laser ablation MC-ICP-MS to assess the potential of rapid Pb-Pb dating of rutile with this method. The rutile samples are from granulite-facies Mg- and Al-rich rocks from the Reynolds Range, Northern Territory, Australia. This metamorphic terrane has a well-constrained high-T ...

The cross sections for the reactions {sup 204}Pb(n,n{sup '}{gamma}){sup 204}Pb{sup m}, {sup 204}Pb(n,2n){sup 203}Pb, {sup 204}Pb(n,2n){sup 203}Pb{sup m1}, {sup 204}Pb(n,3n){sup 202}Pb{sup m}, {sup ...

The deep western boundary current to the east of New Zealand in the southwestern Pacific represents the largest flux of bottom water flow in the ocean system. This is an important area that records the interaction between the Pacific Ocean, the circum-Antarctic oceans and, indirectly, input from North Atlantic Deep Water. We have measured Pb isotope ratios in Fe-Mn nodules ...

Two cores collected in 2001 and 2004 from Flanders Moss ombrotrophic peat bog in central Scotland were dated (14C, 210Pb) and analysed (ICP-OES, ICP-MS) to derive and compare the historical atmospheric deposition records of Sb and Pb over the past 2500 years. After correction, via Sc, for contributions from soil dust, depositional ...

This paper develops and analyses individual construction aspects of an efficient and accurate finite

Pb concentration and Pb isotopic composition are known to represent powerful tools to investigate the history of Pb pollution in water and sediments. In this paper, we present and discuss the results of a detailed study of sediments deposited in the Parano� Lake, a 44-year-old artificial reservoir in Bras�lia, central Brazil. ...

Lead (Pb) isotopic analyses proved to be a very efficient tool for tracing the sources of local and global Pb pollution. This review presents an overview of literature published on the use of Pb isotopic analyses of different environmental matrices (atmospheric aerosols, lichens, tree rings, ...

An aqueous mixture of goethite, quartz, and lead chloride (PbCl(2)) was treated with the sulfate-reducing bacterium, Desulfovibrio desulfuricans G20 (D. desulfuricans G20), in a medium specifically designed to assess metal toxicity. In the presence of 26 muM of soluble Pb, together with the goethite and quartz, D. desulfuricans G20 grew after a lag time of ...

An aqueous mixture of goethite, quartz, and lead chloride (PbCl2) was treated with the sulfatereducing bacterium, Desulfovibrio desulfuricans G20 (D. desulfuricans G20), in a medium specifically designed to assess metal toxicity. In the presence of 26 μM of soluble Pb, together with the goethite and quartz, D. desulfuricans G20 grew after a lag time of 5 ...

Cathodoluminescence (CL) images are routinely used as a guide to locate analysis points in ion probe or laser ablation ICP-MS U-Pb age and trace element analysis of zircon. However, because CL imaging�s clear signals are micron-scale, it cannot reveal depth dependent variation. This is important because typical ion microprobe and laser ablation analysis pits are 1-2 �m and ...

This report presents results of detailed statistical analyses of total and dissolved Pb concentrations in water samples collected from the major aquifer systems in Florida for the FGWQMN [Florida Ground Water Quality Monitoring Network] to determine the influence of anthropogenic factors on elevated Pb concentrations. In addition, ...

Inorganic lead (Pb) is one of the most common environmental pollutants. Much evidence indicates that Pb exposure could directly affect fish growth and development. In this study, we investigated the cytotoxic effects of Pb on cytoskeletal protein stability at both protein and mRNA level in crucian carp Carassius auratus. ...

In the Israel-Stewart's theory of second order hydrodynamics, we have simulated s=2.76 TeV Pb + Pb collisions. ALICE data for the centrality dependence of charged particles multiplicity, p spectra in 0-5% collisions, centrality dependence of integrated and differential elliptic flow are analysed. Analysis indicate that while ALICE data ...

A key factor for accurate and precise isotopic measurements is optimal signal to noise ratio, which makes analyses of very small samples challenging due to the small number of available analyte ions. If, however, the analysis time can be drastically reduced, then very small samples (e.g., 1ng) can be analyzed by placing the analyte ions in small volumes ...

The extinct radionuclide 205Pb, which decays to 205Tl with a half-life of 15 Ma, is of considerable cosmochemical interest, as it is the only short-lived isotope that is produced exclusively by s-process nucleosynthesis. Evidence for the existence of 205Pb in the early solar system has only recently been obtained from analyses of IAB ...

A detailed investigation (218 samples) of Pb isotope variations in the most recent (1975-2007), well- documented and densely sampled eruptions of Piton de la Fournaise has been undertaken (Vlastelic et al, in press). Lead isotopes exhibit smooth temporal fluctuations (18.87<206Pb/204Pb<18.94) on which superimpose rare (5), but ...

A total of forty-three galena samples from syngenetic and epigenetic Pb-Zn mineralizations emplaced in the Lower Cretaceous Basque-Cantabrian basin and Paleozoic basement of the Cinco Villas massif in the western Pyrenees, have been analyzed for Pb-isotopic composition. Galena from sedex mineralizations hosted in Carboniferous clastic rocks in the Cinco ...

Research is reported directed to modification of the anodic stripping voltammetry (ASV) analytic method in order to acquire data for lead from ambient sea water conditions, and development of a chemical model which uses these data to identify inorganic lead species for saline environments. Laboratory and field samples were analyzed for lead partitioning in: (a) KCl electrolyte solutions; (b) ...

Giant monopole resonance strengths were obtained from small angle inelastic alpha scattering on Ni-58 and Pb-208 using deformed potential and folding models. Folding model analyses increase the sum rule strength in both nuclei, with 160% of the E0 sum rule required to fit the 13.7-MeV state in Pb. Significant contributions from other ...

High-resolution geochronology with an age resolution at the permil level is instrumental in testing proposed causal links between continental-scale, short-term volcanic events and environmental crises that affect life globally. Synchroneity with large-scale volcanic events has been shown for three of the five most severe extinctions, namely the end-Permian extinction coinciding with Siberian Trapp ...

We present new high-precision Pb isotopic analyses of 40 historical Kilauea summit lavas (1823-1982). These data provide the opportunity to investigate the architecture of Kilauea�s summit magma storage reservoir and the characteristics of the volcano�s mantle source region. The Pb isotope ratios of the lavas exhibit a fluctuating ...

In 75 active lead workers the median lead level in finger-bone (bone-Pb), as determined in vivo by an X-ray fluorescence method, was 43 micrograms/g (range less than 20-122). In 32 retired workers the median level was even higher, 59 micrograms/g (range less than 20-135), which indicates a slow turnover rate of lead in finger-bone. This was confirmed in 18 of the active ...

The inverse ? decay 205Tl(?,e)205Pb can be used to investigate the solar neutrino flux averaged over the last several million years. The inverse ? decay proceeds dominantly via the 2.3 keV level of the 205Pb and an accurate estimate of the cross section depends on our knowledge of the structure of the 2.3 keV level. We have made the ...

OBJECTIVES: To test a simple procedure for preparing samples for measurement of lead in blood plasma (P-Pb) and whole blood (B-Pb) by inductively coupled plasma mass spectrometry (ICP-MS), to measure P-Pb and B-Pb in lead workers and controls, and to evaluate any differences in the relation between ...

A fast way to carry out the exact-finite range DWBA calculation is discussed, and is applied to the analyses of (/sup 12/C,/sup 11/B) and (/sup 12/ C,/sup 13/C) reactions from /sup 208/Pb. (auth)

Monazite ([LREE, Th]PO4), a common accessory phase in metapelites, is stable over a broad range of metamorphic conditions (greenschist-facies and above) and has been used widely as a (U-Th)/Pb geochronometer in conjunction with thermobarometry to assess the pressure-temperature-time (P-T-t) evolution of metamorphic rocks. While monazite has been less widely exploited as a ...

present LA-ICP-MS U�Pb results from monazites and Rb� Sr analyses from biotites extracted from a major of deep crustal levels. LA-ICPMS U�Pb dating of monazites, combined with Rb�Sr analyses of biotites, from and the subsequent exhumation of deep crustal levels in the internal zones of the Maghrebides. ...

It has been proposed that the neurobiological basis of many of the behavioral manifestations arising in response to Pb exposure may be due to selective vulnerability of particular brain regions, such as hippocampus, a region in which preferential accumulation has been reported in some studies. However, these findings have not been invariant and, in fact, have been found to ...

MC-ICP-MS is now commonly used to detect sub-permil isotopic variations for several metallic chemical elements. High precision isotope ratio measurements are therefore required, necessitating precaution for method validation to obtain accurate results. Although mass discrimination is known to be the main analytical bias of this technique, its modelisation for implementing ...

MC-ICPMS is now commonly used to detect sub-permil isotopic variations for several metallic chemical elements. High precision isotope ratio measurements are therefore required, necessitating precaution for method validation in order to obtain accurate results. Although mass discrimination is known to be the main analytical bias of this technique, its modelisation for ...

The authors have used a nine-parameter expanding source model that includes special relativity, quantum statistics, resonance decays, and freeze-out on a realistic hypersurface in spacetime to analyze in detail invariant {pi}{sup +}, K{sup +}, and K{sup {minus}} one-particle multiplicity distributions and {pi}{sup +} and {pi}{sup {minus}} two-particle correlations in nearly central collisions of ...

For an accurate assessment of immobilization technologies, it is necessary to illustrate the transformation of target metal species into their final products. The present study employed extended X-ray absorption fine structure (EXAFS) spectroscopy combined with linear combination fitting (LCF) to determine Pb species and their proportions in contaminated ...

Rapid Pb Pb dating of natural rutile crystals by laser ablation multiple-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) is investigated as a tool for constraining geological temperature time histories. LA-MC-ICPMS was used to analyse Pb isotopes in rutile from granulite-facies rocks from the ...

New laser ablation MC-ICP-MS measurements of the Pb isotope composition of individual plagioclase and sulfide grains from the Merensky Reef and associated rocks of the Bushveld Complex confirm the veracity of previous analyses (1). The new analyses were obtained using the Nu Plasma instrument at Oregon State University; the original ...

Physiologically-based pharmacokinetic (PB-PK) models attempt to provide both a realistic anatomic description of the animal to which a drug or toxic chemical has been administered and a biologically accurate representation of the physiological pathways for chemical storage, metab...

... the unique isotopic signature of the ore body from which the lead was mined. ... an accurate record of the effects of human-induced lead pollution on the .... Maring, H., Niemeyer, S. (1993) Anthropogenic Pb in Antarctic sea water. ...

It is shown experimentally that the for of the electromagnetic cascade in Pb ionization calorimeters is changed with the angle of incidence. Af a collinear bean of particles passes through the chamber, its behavior is accurate up to an angle of 60 deg . (tr-auth)

TRASCO-ADS is a national funded program in which INFN, ENEA, and Italian industries work on the design of an accelerator driven subcritical system for nuclear waste transmutation. TRASCO is the Italian acronym for Transmutation (TRAsmutazione) of Waste (SCOrie). One of the most critical aspects in the design of an Accelerator Driven System is related to the interface region, which is the part of ...

The suitability of quadrupole inductively coupled plasma-mass spectrometry (ICP-MS) for multielemental analysis of food following microwave closed vessel digestion of samples was evaluated in relation to analytical challenges presented by some major food and agricultural matrixes. Fifteen key analytes (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Se, Sn, V, Zn) were determined ...

Several common materials and methods used to collect interstitial water (IW) were evaluated to determine their effect on the accuracy and precision of measured concentrations of selected organic compounds and metals. The concentration of pollutants in dosed seawater before and after exposure to stainless steel and Teflon centrifuge tubes, glass fiber and Nuclepore filters, cellulose dialysis ...

Inorganic metals and minerals for which there is evidence of carcinogenicity are identified. The risk of cancer from contact with them in the work place, the general environment, and under conditions of clinical (medical) exposure is discussed. The evidence indicates that minerals and metals most often influence cancer development through their action as cocarcinogens. The relationship between the ...

Measurements of ultra-low ambient blood lead (PbB) concentrations (mean {+-} SD = 0.13 {+-} 0.06 {micro}g/dL) in Northern elephant seals (Mirounga angustirostris) validate previous estimates of ultra-low PbB levels in preindustrial humans. These estimates had been unsubstituted, since PbB levels in this range had never been measured in ...

The reaction 208Pb(d,6Li)204Hg has been observed at Ed=55 MeV. Data for several levels in 204Hg up to Ex~=3.5 MeV have been obtained and alpha-particle spectroscopic factors and reduced alpha widths for 208Pb deduced with distorted-wave Born approximation analyses. The reduced alpha widths have been utilized to deduce the "alpha decay" ...

The structure of Tl and Hg isotopes near the /sup 208/Pb core is discussed in terms of a weak-coupling model where low-lying proton-hole states are coupled to low-lying neutron-hole states. The even Pb isotopes are first discussed in terms of a generalized seniority-2 approximation which is shown to be very accurate. The weak-coupling ...

We study relationships between the neutron-rich skin of a heavy nucleus and the properties of neutron-star crusts. Relativistic effective field theories with a thicker neutron skin in 208Pb have a larger electron fraction and a lower liquid-to-solid transition density for neutron-rich matter. These properties are determined by the density dependence of the symmetry energy ...

We have spectrally resolved the intraband transient absorption of photogenerated excitons to quantify the exciton population dynamics in colloidal PbSe quantum dots (QDs). These measurements demonstrate that the spectral distribution, as well as the amplitude, of the transient spectrum depends on the number of excitons excited in a QD. To accurately ...

Excitation functions have been obtained for the exp 206 Pb(p(pol),p) reaction in the vicinity of the 3p exp 1 / sub 2 IAR at 120, 150, and 165 degrees for proton energies of 11-13.6 MeV. This enables accurate determination of the elastic partial width and...

Newly determined Pb isotopic ratios of HF acid-leached feldspars from Middle Proterozoic igneous and metaigneous rocks from the Llano Uplift and Trans-Pecos Texas suggest that these rocks are derived primarily from mantle of petrologically primitive crust. U-Pb geochronologic studies indicate pre-Grenville magmatism ranges in age from 1.35 to 1.23 Ga, ...

Ferromanganese precipitates are widespread phenomena of the Baltic Sea, predominantly caused by seasonal and decadal variations of the redox conditions within the water column and the sediments. 226Raexcess/Ba-dated Mn/Fe-precipitates of the Mecklenburg Bay (20 m water depth) indicate that their growth started at about 4300 years BP. Confirmation of the 226Raexcess/Ba-ages is provided by high ...

Although numerous isotopic analyses have been published for the Aleutians, their interpretation is exceedingly complex. For the arc, Sr, Nd and Pb: have narrow but experimentally significant isotopic ranges. The arc also defines linear Pb-Pb trends distinctly different from other arcs and MORB. Because individual volcanic centers may ...

Studies relating sensory hearing impairment to lead (Pb) exposure in children have presented inconsistent results. The objective of this study was to measure distortion product otoacoustic emissions (DPOAE), sounds emanating from the outer hair cells of the inner ear, in Pb-exposed children to determine the effects of Pb poisoning on ...

Analytical procedures for U-Pb isotope dilution analyses at the Par�-Iso isotope geology laboratory of the Federal University of Par� (UFPA) are described in detail. The procedures are applied to zircon, titanite, rutile, apatite, columbite-tantalite and whole rock. Reagent preparation and chemical processing are done in clean-room conditions. Samples ...

Development of reliable and accurate methodologies for determination of xenobiotic hepatic biotransformation rate and capacity parameters is important to the derivation of precise physiologically-based toxicokinetic (PB-TK) models. Biotransformation data incorporated into PB-TK m...

The ground-state charge densities of /sup 204,206,207,208/Pb have been accurately determined by elastic electron scattering. Mean-field calculations fail to describe the individual charge densities in the central region of the nucleus. However, they properly account for polarization mechanisms in the nuclear interior, as they ...

In spite of the major importance of monazite as a repository for the rare earths and Th in the continental crust, for U-Th-Pb geochronology, and as a possible form for high-level nuclear waste, very little work has been carried out so far on the behaviour of this mineral during fluid-rock events. This contribution describes two contrasting examples of the hydrothermal ...

An investigation of the Pb isotopic compositions of plagioclase and sulfide in a stratigraphic interval including the UG2 chromitite of the eastern Bushveld Complex has been conducted to determine the Pb isotopic composition(s) of the magma(s) that crystallized to form this part of the intrusion, gain a better understanding of why coexisting plagioclase ...

Anthropogenic lead (Pb) inputs to the atmosphere increased greatly over the past century and now dominate Pb supply to the oceans. However, the Pb content of sediments across the equatorial Pacific region is relatively unknown, and data exist only for deep sea sites where Pb deposition lags surface water inputs by ...

Green glass from Apollo 15 lunar clod 15426 (collected from the north rim of Spur Crater), known to be the most primitive among sampled lunar volcanic rocks, was analyzed for Pb isotopic compositions and concentrations of U, Th, and Pb. Hand-picked green glass and yellow impact glass particles were washed with water and a mixture of HBr and HF, and the ...

Rats were exposed to lead (Pb) before or after weaning. For preweaning exposures, nursing dams received 0.2% Pb acetate(1090 ppm Pb) in drinking water. Offspring treated after weaning consumed the same concentration. Tapwater served as the control fluid. Pre-post treatments were distributed among four experimental groups of 10 rats ...

Pyromorphite (Pb5(PO4)3Cl) is one of the most thermodynamically stable lead minerals under the geochemical conditions prevailing in the surface environment. It is therefore expected to form in soils contaminated with Pb if sufficient phosphorus is available. Pyromorphite has previously been identified in mine-waste and industrially contaminated soils but ...

Lead isotope ratios, viz. 207Pb/206Pb and 208Pb/206Pb, of the commercially available certified reference materials (CRMs) issued in Japan are presented with an objective to provide a data set, which will be useful for the quality assurance of analytical procedures, instrumental performance and method validation of ...

The isotopic composition and concentration of Pb was measured in suspended particulate matter of the Irish Sea. Aerosol, surficial and pre-industrial sediment was also analysed to provide information on sources terms. Concentrations of Pb in suspended sediments were lower than previously reported which presumably reflects the ...

Results are presented on U-Pb isotope analyses on experimentally shocked (at 35, 47.5 and 59 GPa) zircon, titanite, and monazite extracted from Proterozoic granitoid rocks, along with U-Pb and Rb-Sr in naturally shocked rocks, zorcon, and monazite obtained from the Haughton Impact Structure (Canada). Results show that shock pressures ...

It has been suggested that lead (Pb) at low exposure levels is a behavior al teratogen. Blood lead (Pb-B) was measured in 185 samples of maternal blood and in 162 samples of cord blood drawn from members of a cohort of mother-infant pairs. Routine newborn assessments, an examination for minor anomalies, the Brazelton Neonatal Behavioral Assessment (NBAS), ...

A series of field investigations have been conducted at Yongzhou Pb/Zn/Cu mine tailings, Hunan Province, southern China. The specific aim was to search for new lead accumulators with fast growth rate and large biomass. The results of tissue analyses identified Typha orientalis Presl has a strong accumulation of lead. The average lead concentrations in the ...

Seedlings of Brassica juncea (L.) Czern. were grown in solution culture for 14 d prior to exposure to Pb?+ at an activity of 31 microM for 72 h. Electron dense deposits found within the apoplast and symplast were analysed using scanning transmission electron microscopy-energy dispersive spectroscopy (STEM-EDS) to determine the chemical identity of the ...

The helical tension of chromosomal DNA is one of the epigenetic landmarks most difficult to examine experimentally. The occurrence of DNA crosslinks mediated by psoralen photobinding (PB) stands as the only suitable probe for assessing this problem. PB is affected by chromatin structure when is done to saturation; but it is mainly determined by DNA helical ...

The helical tension of chromosomal DNA is one of the epigenetic landmarks most difficult to examine experimentally. The occurrence of DNA crosslinks mediated by psoralen photobinding (PB) stands as the only suitable probe for assessing this problem. PB is affected by chromatin structure when is done to saturation; but it is mainly determined by DNA helical ...

A simple radiochemical procedure has been developed to determine 210Pb and 210Po in environmental samples from the same matrix. Sediment samples are decomposed by leaching with mineral acids or by microwave digestion, while water samples are pre-concentrated. One part of the resulting solution, spiked with 209Po, is used for 210Po determination by spontaneous deposition onto ...

Water and mud samples collected during 1973 and 1974 from the Cape Fear River, the region of its plume, and adjacent slope waters were analyzed for lead (Pb) by anodic stripping voltammetry and atomic absorption spectroscopy. Partitioning among adsorbed, strongly complexed, and electroactive states of Pb in seawater was estimated by filtration and ...

Since 1989, a red kite Milvus milvus reintroduction programme has been underway in the United Kingdom, with 4-6 week old nestlings brought into captivity and held for 6-8 weeks before reintroduction. As scavengers, red kites may consume unretrieved game, and ingest shot or lead (Pb) fragments in their prey's flesh. We evaluated exposure to Pb in captive ...

Isotopic analysis of anthropogenic Pb in well-dated, southern California coastal sediments have been integrated with historical changes in ore Pb sources to produce calibration curves (206Pb/207Pb vs. time) that allow us to model the time anthropogenic Pb was added to a soil horizon. The major, ...

New Pb, Sr, and Nd isotope analyses of various crustal units and ores from the Guerrero terrane are presented in order to gain insight into their provenance. Mesozoic basement rocks from the Arteaga Complex and Tejupilco metamorphic suite contain radiogenic Pb relative to bulk earth models ...

The phase diagrams in the PbO-Nb{sub 2}O{sub 5} system and the PbO-Ta{sub 2}O{sub 5} system depict pyrochlore structure at certain molar ratios. Compositions Pb{sub 2}Nb{sub 1.51}Pb{sub 0.49}O{sub 6.30} (1), Pb{sub 2}Ta{sub 1.4}Pb{sub 0.6}O{sub 6.21} (2), and ...

A tissue solubilizer is used to dissolve biological samples without altering the chemical forms of the alkyllead species. The various alkyllead species and lead(II) are isolated quantitatively by chelation extraction with sodium diethyldithlocarbamate, followed by n-butylation to their corresponding tetraalkyl forms, R/sub n/PbBu/sub (4-n)/, and Bu/sub ...

Laser ablation multiple-collector inductively coupled plasma-source mass spectrometry (LA-MC-ICPMS) is a rapid method for obtaining high-precision isotope ratio measurements in geological samples. The method has been used with success for measuring isotope ratios of numerous elements, including Pb, Hf, Mg, Si, and Fe in terrestrial and extraterrestrial samples. It fills the ...

Analytical protocols for accurate and precise Pb isotope ratio determinations in peat, lichen, vegetable, chimney dust, and ore-bearing granites using MC-ICP-MS and their application to environmental studies are presented. Acid dissolution of various matrix types was achieved using high temperature/high pressure microwave and hot plate digestion ...

An alternative thermodiffusion interface (TDI) was designed and constructed for the effective online coupling of capillary gas chromatography (cGC) and inductively coupled plasma mass spectrometry (ICPMS). Pb(2+), (CH3)3Pb(+), (C2H5)3Pb(+), Hg(2+), CH3Hg(+) and C2H5Hg(+) were derived as Pb(C4H9)4, ...

A method for isotopic analyses of Pb in sub-nanogram quantities by thermal ionization mass spectrometry with fractionation correction using 202Pb-205Pb spike was recently reported (Amelin and Davis, JAAS 2006, DOI: 10.1039). The fractionation correction using the ...

Uranium-lead ratios (commonly represented as {sup 238}U/{sup 204}Pb = {mu}) calculated for the sources of martian basalts preserve a record of petrogenetic processes that operated during early planetary differentiation and formation of martian geochemical reservoirs. To better define the range of {mu} values represented by the source regions of martian basalts, we completed ...

We have tested the capabilities of LA-SF-ICPMS for in situ Pb isotopic work on geological glasses using a 213 nm Nd:YAG laser system and a double focusing magnetic sector field ICP mass spectrometer. Experiments were done with the MPI-DING and USGS reference glasses, USGS rock powders molten as glass beads and basaltic glasses from Hawaii. In particular, the precision and ...

Pb and Al in blood and hair of child were determined by transverse heated graphite furnace atomic absorption spectrometry with NH4H2PO4 and Mg(NO3)2 as a modifier, which enhanced the temperature of ashing, eliminated the matrix interference and memorial effect. The method is rapid, simple and accurate. The characteristic mass of the method was 2.3 x ...

A precise determination of the neutron skin ?rnp of a heavy nucleus sets a basic constraint on the nuclear symmetry energy (?rnp is the difference of the neutron and proton rms radii of the nucleus). The parity radius experiment (PREX) may achieve it by electroweak parity-violating electron scattering (PVES) on Pb208. We investigate PVES in nuclear mean field approach to allow ...

The USAF Surgeon General approved pyridostigmine bromide (PB) pretreatment for flying personnel as of 21 March 1986. However, specific side effects resulting from taking PB during high sustained + G/sub z/ stress, altitude stress, and periods of potential spatial disorientation had not yet been fully investigated. The USAF school of Aerospace Medicine ...

We have analyzed the latest NA50 data on J/psi suppression in Pb + Pb collisions. J/psi production is assumed to be a two-step process: (i) formation of a cc- pair, which is accurately calculable in QCD, and (ii) formation of a J/psi meson from the cc- pair, which can be conveniently parametrized. The parameters of the model were fixed ...

The Poisson-Boltzmann (PB) equation is an established multiscale model for electrostatic analysis of biomolecules and other dielectric systems. PB based molecular dynamics (MD) approach has a potential to tackle large biological systems. Obstacles that hinder the current development of PB based MD methods are concerns in accuracy, ...

The Poisson-Boltzmann (PB) equation is an established multiscale model for electrostatic analysis of biomolecules and other dielectric systems. PB based molecular dynamics (MD) approach has a potential to tackle large biological systems. Obstacles that hinder the current development of PB based MD methods are concerns in accuracy, ...

The authors present a rapid and accurate technique for making in situ U-Pb isotopic measurements of uranium oxide minerals that utilizes both electron and ion microprobes. U and Pb concentrations are determined using an electron microprobe, whereas the isotopic composition of Pb for the same area is measured using ...

At contaminated sites the concentration of Pb2+ in soil solution may be governed by the solubility of Pb phosphates. It has been observed, however, that the Pb leaching into the groundwater is higher than calculated from the solubility product of Pb pre- cipitates. We hypothesize that this is due to colloidal ...

Calibration of recently installed proportional counter at the Hot Cells Facility of the Jozef Stefan Institute was performed. Instrument was calibrated for determination of total beta activity, Sr-90 and Pb-210. Detection efficiencies for K-40, Sr-90, Y-90, Pb-210 and Bi-210 were determined, allowing for more accurate determination of ...

Prior work has suggested that (carboxymethyl)-beta-cyclodextrin (CMCD) is capable of simultaneously enhancing the solubility of organics and metals, but sparse experimental data and no theoretical models have been published on this process. Preciously, a geochemical model for metal complexation by CMCD was formulated using PHREEQC on the basis of conditional stability constants measured in ...

Macrofungi can accumulate some minerals, including toxic metals if present in the substrate. A periodic monitoring of these elements in mushrooms is recommended when the conditions of cultivation are altered. The aim of this work was to evaluate the mineral content of Pleurotus spp (hiratake and shimeji) and of imported (chilean and italian) dehydrated mushrooms. Fresh fruiting bodies of Pleurotus ...

As part of the Atmosphere/Ocean Chemistry Experiment (AE-ROCE), daily aerosol samples were collected at Bermuda and Barbados. In addition, gas-phase [sup 222]Rn concentrations were analyzed hourly from July 1991 to June 1992. Isentropic analyses, isentropic trajectories, and non-isentropic tranjectories were used to understand the long-range transport of these substances. In ...

As part of the Atmosphere/Ocean Chemistry Experiment (AEROCE), daily aerosol samples were collected at Bermuda and Barbados. In addition, gas-phase (222)Rn concentrations were analyzed hourly from July 1991 to June 1992. Isentropic analyses, isentropic trajectories, and non-isentropic trajectories were used to understand the long-range transport of these substances. In ...

The quadrupole moment of the deuteron, Q, was determined to a relative accuracy of +/-7% from measurements of T/sub 20/ for /sup 208/Pb(d,d) at a deuteron bombarding energy of 4 MeV. This bombarding energy is sufficiently far below the Coulomb barrier that T/sub 20/ results primarily from the electrostatic interaction between the quadrupole moment of the deuteron and the ...

From data on elemental concentrations in human tissues, Liebscher and Smith (1968) hypothesized that the frequency distributions of concentrations for essential elements were normal distributions, whereas the frequency distributions for nonessential elements were lognormal distributions. Although Liebscher and Smith's justifications for this hypothesis are flawed, other researchers have ...

K-Ar ages ranging from about 600 to 1000 Ma have recently been reported for gabbro and basalt recovered from the Texaco 1 Poersch well in Kansas. This has prompted suggestions that rift magmatism there may be distinctly younger than that in the Lake Superior region, and that development of the rift may have lasted several hundred million years. Review of ages from Keweenawan volcanic and plutonic ...

The aim of the study was to determine total trace (Cd, Co, Cr, Cu, Mn, Pb and Zn) and major (Al and Fe) element concentrations in calcareous soils using microwave-assisted digestion procedures. The literature showing lack of consensus regarding digestion procedures and unsatisfying recoveries for calcareous materials, four procedures using various acid combinations (HCl, ...

Feathers provide a potentially useful biomonitoring option in studies regarding pollution exposure in avian species. However, they must be used with care because the complex, fine structure is highly prone to accumulating surface contamination. This may therefore give a misleading indication of pollutant intake in the animal. Here, data are presented for 4 large scavenging raptor species collected ...

Pb was incorporated to a series of cement matrices, which were submitted to different testes of solidified/stabilized product. The leaching behaviors of aqueous solution were monitored by graphite furnace atomic absorption spectroscopy (GF-AAS). The mechanical strengths were evaluated by unconfined compressive strength (UCS) at 7 and 28 ages. Data are discussed in terms of ...