Three-dimensional magnetic resonance imaging for groundwater

International audienceThe surface nuclear magnetic resonance method (SNMR) is an established geophysical tool routinely used for investigating one-dimensional (1D) and sometimes 2D subsurface water-saturated formations. We have expanded the tool by developing a 3D application. 3D-SNMR is a large-scale method that allows magnetic resonance imaging of groundwater down to about 80 m. Similar to most surface geophysical methods, 3D-SNMR has limited resolution, but it is effective for investigating water-saturated geological formations larger than several tens of meters. Because the performance of the method depends on variable survey conditions, we cannot estimate it in general. For demonstration purposes, we present an example of numerical modeling under fixed conditions. Results show that under certain conditions it is possible to detect a water volume as small as 500 m(3) and the detection threshold depends on the ambient electromagnetic noise magnitude and on the location of the target volume relative to the SNMR loops. The 3D-SNMR method was used to investigate accumulated water within the Tete Rousse glacier (French Alps). Inversion of the field measurements made it possible to locate the principal reservoir in the central part of the glacier and estimate the volume of accumulated water. These results were verified by 20 boreholes installed after the 3D-SNMR results were obtained and by pumping water out of the glacier. Very good correspondence between the 3D-SNMR and borehole results was observed

(2,2-Dichloro­vinyl)ferrocene

The title compound, [Fe(C5H5)(C7H5Cl2)], represents a versatile building block for the preparation of π-conjugated redox-active compounds or polymetallic organometallic systems due to the presence of the electrochemically active ferrocenyl unit. It is therefore a potential starting material for the preperation of the corresponding alkyne. In the crystal, the alkenyl unit and the cyclo­penta­dienide ring are almost parallel, with an angle between the best planes of only 10.6 (4)°

Interactive comment on “Monitoring water accumulation in a glacier using magnetic resonance imaging” by A. Legchenko et al.

Tête Rousse is a small polythermal glacier located in the Mont Blanc area (French Alps) at an altitude of 3100 to 3300 m. In 1892, an outburst flood from this glacier released about 200 000 m3 of water mixed with ice, causing much damage. A new accumulation of melt water in the glacier was not excluded. The uncertainty related to such glacier conditions initiated an extensive geophysical study for evaluating the hazard. Using three-dimensional surface nuclear magnetic resonance imaging (3-D-SNMR), we showed that the temperate part of the Tête Rousse glacier contains two separate water-filled caverns (central and upper caverns). In 2009, the central cavern contained about 55 000 m3 of water. Since 2010, the cavern is drained every year. We monitored the changes caused by this pumping in the water distribution within the glacier body. Twice a year, we carried out magnetic resonance imaging of the entire glacier and estimated the volume of water accumulated in the central cavern. Our results show changes in cavern geometry and recharge rate: in two years, the central cavern lost about 73% of its initial volume, but 65% was lost in one year after the first pumping. We also observed that, after being drained, the cavern was recharged at an average rate of 20 to 25 m3 d−1 during the winter months and 120 to 180 m3 d−1 in summer. These observations illustrate how ice, water and air may refill englacial volume being emptied by artificial draining. Comparison of the 3-D-SNMR results with those obtained by drilling and pumping showed a very good correspondence, confirming the high reliability of 3-D-SNMR imaging

Comparison of the Hemostatic Efficacy of Pathogen-Reduced Platelets vs Untreated Platelets in Patients With Thrombocytopenia and Malignant Hematologic Diseases: A Randomized Clinical Trial

Importance: Pathogen reduction of platelet concentrates may reduce transfusion-transmitted infections but is associated with qualitative impairment, which could have clinical significance with regard to platelet hemostatic capacity. Objective: To compare the effectiveness of platelets in additive solution treated with amotosalen-UV-A vs untreated platelets in plasma or in additive solution in patients with thrombocytopenia and hematologic malignancies. Design, Setting, and Participants: The Evaluation of the Efficacy of Platelets Treated With Pathogen Reduction Process (EFFIPAP) study was a randomized, noninferiority, 3-arm clinical trial performed from May 16, 2013, through January 21, 2016, at 13 French tertiary university hospitals. Clinical signs of bleeding were assessed daily until the end of aplasia, transfer to another department, need for a specific platelet product, or 30 days after enrollment. Consecutive adult patients with bone marrow aplasia, expected hospital stay of more than 10 days, and expected need of platelet transfusions were included. Interventions: At least 1 transfusion of platelets in additive solution with amotosalen-UV-A treatment, in plasma, or in additive solution. Main Outcomes and Measures: The proportion of patients with grade 2 or higher bleeding as defined by World Health Organization criteria. Results: Among 790 evaluable patients (mean [SD] age, 55 [13.4] years; 458 men [58.0%]), the primary end point was observed in 126 receiving pathogen-reduced platelets in additive solution (47.9%; 95% CI, 41.9%-54.0%), 114 receiving platelets in plasma (43.5%; 95% CI, 37.5%-49.5%), and 120 receiving platelets in additive solution (45.3%; 95% CI, 39.3%-51.3%). With a per-protocol population with a prespecified margin of 12.5%, noninferiority was not achieved when pathogen-reduced platelets in additive solution were compared with platelets in plasma (4.4%; 95% CI, -4.1% to 12.9%) but was achieved when the pathogen-reduced platelets were compared with platelets in additive solution (2.6%; 95% CI, -5.9% to 11.1%). The proportion of patients with grade 3 or 4 bleeding was not different among treatment arms. Conclusions and Relevance: Although the hemostatic efficacy of pathogen-reduced platelets in thrombopenic patients with hematologic malignancies was noninferior to platelets in additive solution, such noninferiority was not achieved when comparing pathogen-reduced platelets with platelets in plasma. Trial Registration: clinicaltrials.gov Identifier: NCT01789762

The Effects of Apolipoprotein F Deficiency on High Density Lipoprotein Cholesterol Metabolism in Mice

Apolipoprotein F (apoF) is 29 kilodalton secreted sialoglycoprotein that resides on the HDL and LDL fractions of human plasma. Human ApoF is also known as Lipid Transfer Inhibitor protein (LTIP) based on its ability to inhibit cholesteryl ester transfer protein (CETP)-mediated transfer events between lipoproteins. In contrast to other apolipoproteins, ApoF is predicted to lack strong amphipathic alpha helices and its true physiological function remains unknown. We previously showed that overexpression of Apolipoprotein F in mice reduced HDL cholesterol levels by 20–25% by accelerating clearance from the circulation. In order to investigate the effect of physiological levels of ApoF expression on HDL cholesterol metabolism, we generated ApoF deficient mice. Unexpectedly, deletion of ApoF had no substantial impact on plasma lipid concentrations, HDL size, lipid or protein composition. Sex-specific differences were observed in hepatic cholesterol content as well as serum cholesterol efflux capacity. Female ApoF KO mice had increased liver cholesteryl ester content relative to wild type controls on a chow diet (KO: 3.4+/−0.9 mg/dl vs. WT: 1.2+/−0.3 mg/dl, p<0.05). No differences were observed in ABCG1-mediated cholesterol efflux capacity in either sex. Interestingly, ApoB-depleted serum from male KO mice was less effective at promoting ABCA1-mediated cholesterol efflux from J774 macrophages relative to WT controls

A Theory for the High-T_c Cuprates: Anomalous Normal-State and Spectroscopic Properties, Phase Diagram, and Pairing

A theory of highly correlated layered superconducting materials isapplied for the cuprates. Differently from an independent-electron approximation, their low-energy excitations are approached in terms of auxiliary particles representing combinations of atomic-like electron configurations, where the introduction of a Lagrange Bose field enables treating them as bosons or fermions. The energy spectrum of this field accounts for the tendency of hole-doped cuprates to form stripe-like inhomogeneities. Consequently, it induces a different analytical behavior for auxiliary particles corresponding to "antinodal" and "nodal" electrons, enabling the existence of different pairing temperatures at T^* and T_c. This theory correctly describes the observed phase diagram of the cuprates, including the non-Fermi-liquid to FL crossover in the normal state, the existence of Fermi arcs below T^* and of a "marginal-FL" critical behavior above it. The qualitative anomalous behavior of numerous physical quantities is accounted for, including kink- and waterfall-like spectral features, the drop in the scattering rates below T^* and more radically below T_c, and an effective increase in the density of carriers with T and \omega, reflected in transport, optical and other properties. Also is explained the correspondence between T_c, the resonance-mode energy, and the "nodal gap".Comment: 28 pages, 7 figure

Genome Stability of Lyme Disease Spirochetes: Comparative Genomics of Borrelia burgdorferi Plasmids

Lyme disease is the most common tick-borne human illness in North America. In order to understand the molecular pathogenesis, natural diversity, population structure and epizootic spread of the North American Lyme agent, Borrelia burgdorferi sensu stricto, a much better understanding of the natural diversity of its genome will be required. Towards this end we present a comparative analysis of the nucleotide sequences of the numerous plasmids of B. burgdorferi isolates B31, N40, JD1 and 297. These strains were chosen because they include the three most commonly studied laboratory strains, and because they represent different major genetic lineages and so are informative regarding the genetic diversity and evolution of this organism. A unique feature of Borrelia genomes is that they carry a large number of linear and circular plasmids, and this work shows that strains N40, JD1, 297 and B31 carry related but non-identical sets of 16, 20, 19 and 21 plasmids, respectively, that comprise 33–40% of their genomes. We deduce that there are at least 28 plasmid compatibility types among the four strains. The B. burgdorferi ∼900 Kbp linear chromosomes are evolutionarily exceptionally stable, except for a short ≤20 Kbp plasmid-like section at the right end. A few of the plasmids, including the linear lp54 and circular cp26, are also very stable. We show here that the other plasmids, especially the linear ones, are considerably more variable. Nearly all of the linear plasmids have undergone one or more substantial inter-plasmid rearrangements since their last common ancestor. In spite of these rearrangements and differences in plasmid contents, the overall gene complement of the different isolates has remained relatively constant