Zinc systematics quantify crustal thickness control on fractionating assemblages of arc magmas.

Understanding the processes leading to the broad chemical variability of arc magmas is an essential, yet not fully elucidated, issue in Earth Sciences. Here, I show that Zn-MgO-SiO2 systematics of magmatic arc rocks correlate significantly with arc thickness. Because Zn-MgO-SiO2 systematics are mostly controlled by fractionation of different mineral phases, this suggests a systematic change in the proportions of fractionating mineral assemblages depending on arc thickness. Using a mass balance model with a Monte Carlo approach, I show that Zn-MgO-SiO2 systematics can be quantitatively explained by a continuous transition from plagioclase-dominated fractionating assemblages in thin arcs to amphibole-garnet-magnetite-dominated assemblages in increasingly thicker arcs. Most likely, such a systematic change results from the increase of average depth of magma differentiation that is ultimately controlled by arc thickness. Results presented have implications on the causes of different geochemical trends in arcs, the role of arcs as H2O filters, and their association with porphyry deposits.

Geochronology and geochemistry data for the Elbrus, Tyrnyauz, and Chegem magmatic centers, Greater Caucasus, Russia.

The dataset presented here is associated with the article "Young Silicic Magmatism of the Greater Caucasus, Russia with implication for its delamination origin based on zircon petrochronology and thermomechanical modeling" [1]. We present detailed sample descriptions and source locations for the rocks from the Chegem, Tyrnyauz, and Elbrus volcanic center localities presented in that study. The dataset presents extensive isotope and trace element geochemistry of zircon crystals from these rocks, major phenocrysts, and whole rock O and H isotopic and elemental compositions. Zircon ages, trace element compositions, and Hf and O isotopic compositions were obtained by both laser ablation ICP-MS and secondary ionization mass spectrometry in situ techniques and chemical abrasion isotope dilution-thermal ionization mass spectrometry techniques. We also present whole-rock major element compositions obtained by X-ray fluorescence and trace element compositions obtained by solution inductively-coupled plasma mass spectrometry. We also report δ18O analyses of phenocrysts and groundmass in samples, δ18O-δ13C analyses of limestones and limestone xenoliths in the Chegem ignimbrite, and coupled δ18O-δD-Δ17O analyses of glass and groundmass of rock samples from the Chegem ignimbrites that show abundant evidence of post-emplacement interaction with meteoric waters. To supplement the associated study [1], this article also includes field photographs, cathodoluminescence images of zircons, plots of trace element compositions in zircon, plots of stable isotopic variations in Chegem ignimbrites vs. stratigraphy, and selected trace elemental whole-rock diagrams.

Iterative reconstructions in multiphasic CT imaging of the liver: qualitative and task-based analyses of image quality.

AIM: To evaluate the clinical benefits on image quality (IQ) of adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in multiphasic liver CT compared to filtered back-projection (FBP), in patients and on phantoms using a novel task-based metric. MATERIALS AND METHODS: Image data of 65 patients who underwent a routine multiphasic liver CT during a 1-month period were reconstructed with FBP, ASIR50, ASIR80, and MBIR. IQ was assessed qualitatively by ranking the most distal hepatic artery (HA) and portal vein (PV) visible; and quantitatively by measuring contrast-to-noise ratio (CNR) of the liver parenchyma, HA and PV. IQ was compared between each reconstruction and correlated to CNR and detectability index (d') measurements computed on phantoms scanned with the same CT protocol as for patients. RESULTS: HA and PV were seen more distally on MBIR and ASIR80 compared to FBP (p≤0.001). The CNR correlated weakly between patient and phantom (r=0.76 and 0.80 for HA and PV, respectively), whereas d' correlated strongly with the division order of HA and PV (r=0.96 and 0.95, respectively). CONCLUSION: MBIR and ASIR significantly improve the IQ of multiphasic liver CT, especially through better distal detection of HA and PV, in agreement with the adapted task-based metric d' estimated on phantoms.

[Prostate cancer diagnostic by saturation randomized biopsy versus rigid targeted biopsy]. / Détection du cancer de prostate par biopsies de saturation versus biopsies ciblées fusion d'image rigide.

INTRODUCTION: Optimal diagram teaming up randomized biopsy (BR) to targeted biopsy (BC) is still missing for the diagnostic of prostate cancer (CP). This study compares diagram of 6, 12 or 18 BR with or without BC rigid. METHODS: Between January 2014 and May 2016, 120 patients had prostate biopsy BR and BC. Each patient had 18 BR and BC. Results compared sextant (6 BR), standard (12 BR) and saturation (18 BR) protocol with or without the adding of BC for the detection of CP. RESULTS: Rectal examination was normal, mean PSA at 8.99ng/mL and mean volume at 54cm3. It was first round for 48% of patients. Forty-four cancers were found by the group 18 BR+BC (control). The detection rate was respectively, for 6, 12 and 18 BR of 61%, 82% and 91%. The add of BC increased this detection of +27% for 6 BR+BC, +13% for 12 BR+BC and +9% for 18 BR+BC. BC found 70% of all CP. Nine percent of CP were missed by BR only. Significant CP (Gleason≥7) diagnostic was the same for 12 BR+BC and 18 BR+BC. CONCLUSION: The add of BC to BR increase the detection of CP by 10%. Twelve BR+BC is the optimal diagram for the diagnostic of CP finding 95% of CP and 97% of significant CP. LEVEL OF EVIDENCE: 4.

Post-procedure bleeding in interventional radiology.

Following interventional radiology procedures, bleeding can occur in 0.5 to 4% of the cases. Risk factors are related to the patient, to the procedure, and to the end organ. Bleeding is treated usually by interventional radiologists and consists mainly of embolization. Bleeding complications are preventable: before the procedure by checking hemostasis, during the procedure by ensuring the accurate puncture site (with ultrasound or fluoroscopy guidance) or by treating the puncture path using gelatin sponge, curaspon(®), biological glue or thermocoagulation, and after the procedure by carefully monitoring the patients.

Ruptured visceral artery aneurysms.

Visceral artery aneurysms are rare but their estimated mortality due to rupture ranges between 25 and 70%. Treatment of visceral artery aneurysm rupture is usually managed by interventional radiology. Specific embolization techniques depend on the location, affected organ, locoregional arterial anatomy, and interventional radiologist skill. The success rate following treatment by interventional radiology is greater than 90%. The main complication is recanalization of the aneurysm, showing the importance of post-therapeutic monitoring, which should preferably be performed using MR imaging.

Imaging strategies before beginning treatment of colorectal liver metastases.

The management of colorectal intrahepatic metastases before resection is multidisciplinary and radiologists and nuclear medicine specialists play a major role. In accordance with the French National Guide for appropriate use of diagnostic imaging, the approach should be multimodal: a chest-abdomen and pelvic (CAP) CT scan and hepatic MRI are mandatory while PET-CT provides important additional information, in particular on intra-abdominal extrahepatic metastases. This multimodal approach emphasizes the importance of early and appropriate use of imaging in these patients, as well as the central role of multidisciplinary meetings in oncology.

Imaging benign hepatocellular tumors: atypical forms and diagnostic traps.

Management of patients with a benign hepatocellular tumor relies largely on imaging data; the diagnosis of focal nodular hyperplasia (FNH) must be made with certainty using MRI, because no other clinical or laboratory data can help diagnosis. It is also essential to identify adenomas to manage them appropriately. The radiological report in these situations is therefore of major importance. However, there are diagnostic traps. The aim of this paper is to present the keys to the diagnosis of benign lesions and to warn of the main diagnostic pitfalls.

Diffusion-weighted MR imaging of the normal pancreas: reproducibility and variations of apparent diffusion coefficient measurement at 1.5- and 3.0-Tesla.

PURPOSE: To evaluate reproducibility and variations in apparent diffusion coefficient (ADC) measurement in normal pancreatic parenchyma at 1.5- and 3.0-Tesla and determine if differences may exist between the four pancreatic segments. MATERIALS AND METHODS: Diffusion-weighted MR imaging of the pancreas was performed at 1.5-Tesla in 20 patients and at 3.0-Tesla in other 20 patients strictly matched for gender and age using the same b values (0, 400 and 800s/mm(2)). Two independent observers placed regions of interest within the four pancreatic segments to measure ADC at both fields. Intra- and inter-observer agreement in ADC measurement was assessed using Bland-Altman analysis and comparison between ADC values obtained at both fields using non-parametrical tests. RESULTS: There were no significant differences in ADC between repeated measurements and between ADC obtained at 1.5-Tesla and those at 3.0-Tesla. The 95% limits of intra-observer agreement between ADC were 2.3%-22.7% at 1.5-Tesla and 1%-24.2% at 3.0-Tesla and those for inter-observer agreement between 1.9%-14% at 1.5-Tesla and 8%-25% at 3.0-Tesla. ADC values were similar in all pancreatic segments at 3.0-T whereas the tail had lower ADC at 1.5-Tesla. CONCLUSION: ADC measurement conveys high degrees of intra- and inter-observer reproducibility. ADC have homogeneous distribution among the four pancreatic segments at 3.0-Tesla.

Identification of historical lead sources in roof dusts and recent lake sediments from an industrialized area: indications from lead isotopes.

X-ray fluorescence and stable lead (Pb) isotopic analyses have been undertaken on dusts, known from microscopic investigation to contain significant quantities of industrially- and urban-derived particulate matter, present in the roof cavities of houses in the Illawarra region (N.S.W., Australia), with the objective of examining the historic record of Pb pollution. All investigated houses contained in excess of 250 micrograms g-1 Pb, with dwellings close to a copper smelter, in a large industrial complex including a major steelworks, containing higher (> 2500 micrograms g-1) Pb concentrations. The isotopic composition in the dusts, expressed here as 206Pb/204Pb, is relatively constant at 17.0, irrespective of dwelling age or distance from the industrial complex. Contamination of the dusts by Pb sourced from paint cannot explain the isotopic uniformity of the dust samples. Isotopic modelling indicates that the dusts contain Pb derived from the copper smelter, gasoline-air Pb and a minor contribution from coal-utilising sources. Lead loading was also investigated in the adjacent lagoon, which acts as a natural sink for particulate matter in the Illawarra region. Isotopic data and modelling indicate that one natural and four anthropogenic sources contribute to the Pb burden of this lagoon. The natural source consists of Permian rocks cropping out in the catchment area which have a 206Pb/204Pb of approximately 18.7. The suggested anthropogenic sources are an old disbanded base-metal (Pb) smelter (206Pb/204Pb approximately 16.2-16.3), the copper smelter (206Pb/204Pb approximately 17.9), gasoline-air derived Pb (206Pb/204Pb approximately 16.4-16.5) and industries utilising coal, for example the recently closed thermal coal-fired power station (206Pb/204Pb approximately 18.9). The relative contributions of the base-metal (mainly lead) smelter and gasoline-air Pb in the sediment can only be partly assessed due to the isotopic similarity of these sources. Likewise the natural background and coal source (e.g. power station) contributions can only be estimated from historical data. Age estimations for sediment cores, using 137Cs, provide some control on these assessments. Near surface sediments in the lagoon have a relatively constant 206Pb/204Pb of 17.6-17.7, irrespective of sample location. Isotopic calculations, together with records of particulate matter pollution emissions, indicate a link between the Pb in roof dusts (206Pb/204Pb approximately 17.0) and Pb contamination of the near surface (upper 20 cm) lagoonal sediments via a homogeneous, non-unique source of lead whose isotopic composition closely matches that of the dusts. Over the last 5 decades, atmospheric fallout of Pb-bearing particulate matter appears to have been the dominant pathway for addition of Pb to the lagoon and dwellings in the Illawarra region.

The efficiency of removal of lead and other elements from domestic drinking waters using a bench-top water filter system.

The efficiency of removal of lead (Pb) and other elements from natural drinking waters using a bench-top water filter system was evaluated in three recently-built houses in Sydney, Australia, and two from rural centres. In addition, one filter system was tested for copper (Cu), Pb and cadmium (Cd) under rigorously-controlled laboratory conditions using Sydney water. For two Sydney houses, the efficiency was evaluated using special filter cartridges concomitant with the ordinary filters. Waters after passing through the filter, was sampled when the filter had been exposed to '0', 50, 100, 150, 200, and 250 l respectively and were analysed for lead isotopes and lead concentrations by high precision isotope dilution mass spectrometry. Samples that passed through the filter after '0', 50, 150 and 250 l collections were analysed for four anions and 39 cations by various methods. Sydney water was fairly uniform in its anion and cation composition, whereas water from the two rural areas contained higher concentrations of Ca, Mg and HCO3. Effects of the filter on the water compositions can be summarised into three groups: (1) elements removed during filtration--Ca, Mg, Sr, Ba, Cu, Pb, Zn and Ni. With 'age' of the filter, the efficiency of removal for Pb was maintained in the two houses with Pb concentrations greater than 10 micrograms/l in the first flush water and was maintained for Cu through all concentrations. Ca, Mg, Sr and Ba were largely removed in the first 50 1 of usage. (2) Elements added during filtration--K, Rb, Ag and P. Except for Ag, which was present throughout the testing period, these elements were added only in the first filtration. (3) Elements unaffected by filtration--Al, Si, Na, Fe, Cl and F. Efficiency of Pb removal from tap water by this system depends generally on the initial Pb content in the water. However, it also seems to depend, to some extent, on Pb speciation and water composition, as found in earlier studies of natural waters. The control in filtering efficiency as a function of Pb speciation and chemical composition becomes more important at low initial Pb concentrations in the water. However, the Pb concentrations at which speciation and water composition appear to play a role in filter efficiency are so low that these factors, though scientifically interesting, have no relevance from a practical point of view, especially the impact on human health. Acidification of six sets of duplicate water samples, one sample immediately after collection and the other acidified after more than 2 weeks, showed negligible changes in Pb or Cu concentrations between duplicates.

Contamination of houses by workers occupationally exposed in a lead-zinc-copper mine and impact on blood lead concentrations in the families.

OBJECTIVE: To evaluate the pathway of leaded dust from a lead-zinc-copper mine to houses of employees, and the impact on blood lead concentrations (PbB) of children. METHODS: High precision lead isotope and lead concentration data were obtained on venous blood and environmental samples (vacuum cleaner dust, interior dustfall accumulation, water, paint) for eight children of six employees (and the employees) from a lead-zinc-copper mine. These data were compared with results for 11 children from occupationally unexposed control families living in the same city. RESULTS: The median (range) concentrations of lead in vacuum cleaner dust was 470 (21-1300) ppm. In the houses of the mine employees, vacuum cleaner dust contained varying higher proportions of mine lead than did airborne particulate matter measured as dustfall accumulated over a three month period. The median (range) concentrations of lead in soil were 30 (5-407) ppm and these showed no evidence of any mine lead. Lead in blood of the mine employees varied from 7 to 25 micrograms/dl and was generally dominated by mine lead (> 60%). The mean (SD) PbB in the children of the mine employees was 5.7 (1.7) micrograms/dl compared with 4.1 (1.4) micrograms/dl for the control children (P = 0.02). The PbB of all children was always < 10 micrograms/dl, the Australian National Health and Medical Research Council goal for all Australians. Some of the control children had higher PbB than the children of mine employees, probably from exposure to leaded paint as six of the eight houses of the control children were > 50 years old. In five of the eight children of mine employees > 20% of PbB was from the lead mine. However, in the other three cases of children of mine employees, their PbB was from sources other than mine lead (paint, petrol, background sources). CONCLUSIONS: Houses of employees from a lead mine can be contaminated by mine lead even if they are not situated in the same place as the mine. Delineation of the mine to house pathway indicates that lead is probably transported into the houses on the clothes, shoes, hair, skin, and in some cases, motor vehicles of the workers. In one case, dust shaken from clothes of a mine employee contained 3000 ppm lead which was 100% mine lead. The variable contamination of the houses was not expected given the precautions taken by mine employees to minimise transportation of lead into their houses. Although five out of the eight children of mine employees had > 20% mine lead in their blood, in no case did the PbB of a child exceed the Australian National Health and Medical Research Council goal of 10 micrograms/dl. In fact, some children in the control families had higher PbB than children of mine employees. In two cases, this was attributed to a pica habit for paint. The PbB in the children of mine employees and controls was independent of the source of lead. The low PbB in the children of mine employees may reflect the relatively low solubility (bioavailability) of the mine dust in 0.1 M hydrochloric acid (< 40 %), behaviour--for example, limited mouthing activity--or diet.

Multiwire proportional chamber system of the Fermilab single arm spectrometer.

We describe a system of two groups of multiwire proportional chambers and its special purpose interface used in the Single Arm Spectrometer (SAS) facility at Fermilab. The first set measures the coordinates of the fast particle going into the spectrometer arm with a space resolution down to +/-0.5 mm. The second set, close to the target, measures the multiplicity and angular distributions of charged particles coming from the interaction. The chambers of this set have three sensitive planes with wires at 120 degrees in the same gas volume to measure three coordinates for each physical point, two readout channels per wire to minimize the inefficiency due to the very high flux and insensitive regions at the center of the chambers where they are crossed by the beam.