400 research outputs found

    Depth concentrations of deuterium ions implanted into some pure metals and alloys

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    Pure metals (Cu, Ti, Zr, V, Pd) and diluted Pd-alloys (Pd-Ag, Pd-Pt, Pd-Ru, Pd-Rh) were implanted by 25 keV deuterium ions at fluences in the range (1.2{\div}2.3)x1022 D+/m2. The post-treatment depth distributions of deuterium ions were measured 10 days and three months after the implantation using Elastic Recoil Detection Analysis (ERDA) and Rutherford Backscattering (RBS). Comparison of the obtained results allowed to make conclusions about relative stability of deuterium and hydrogen gases in pure metals and diluted Pd alloys. Very high diffusion rates of implanted deuterium ions from V and Pd pure metals and Pd alloys were observed. Small-angle X-ray scattering revealed formation of nanosized defects in implanted corundum and titanium.Comment: 12 pages, 9 figure

    Growth conditions, structure, and superconductivity of pure and metal-doped FeTe1-xSex single crystals

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    Superconducting single crystals of pure FeTe1 xSex and FeTe0.65Se0.35 doped with Co, Ni, Cu, Mn, Zn, Mo, Cd, In, Pb, Hg, V, Ga, Mg, Al, Ti, Cr, Sr or Nd into Fe ions site have been grown applying Bridgman's method. It has been found that the sharpness of transition to the superconducting state in FeTe1 xSex is evidently inversely correlated with crystallographic quality of the crystals. Among all of the studied dopants only Co, Ni and Cu substitute Fe ions in FeTe0.65Se0.35 crystals. The remaining examined ions do not incorporate into the crystal structure. Nevertheless, they form inclusions together with selenium, tellurium and/or iron, what changes the chemical composition of host matrix and therefore influences Tc value. Small disorder introduced into magnetic sublattice, by partial replacement of Fe ions by slight amount of nonmagnetic ions of Cu (~ 1.5 at%) or by magnetic ions of Ni (~ 2 at%) and Co (~5 at%) with spin value different than that of Fe ion, completely suppresses superconductivity in FeTe1 xSex system. This indicates that even if superconductivity is observed in the system containing magnetic ions it can not survive when the disorder in magnetic ions sublattice is introduced, most likely because of magnetic scattering of Cooper pairs.Comment: 18 pages, 12 figures, 3 table

    Rational curves and bounds on the Picard number of Fano manifolds

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    We prove that Generalized Mukai Conjecture holds for Fano manifolds XX of pseudoindex iX(dimX+3)/3i_X \ge (\dim X +3)/3. We also give different proofs of the conjecture for Fano fourfolds and fivefolds.Comment: Modified the proof of the main theorem and eliminated a statement about the cone of curves. To appear in Geometriae Dedicat

    Einstein black holes, free scalars and AdS/CFT correspondence

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    We investigate AdS/CFT correspondence for two families of Einstein black holes in d > 3 dimensions, modelling the boundary CFT by a free conformal scalar field and evaluating the boundary two-point function in the bulk geodesic approximation. For the d > 3 counterpart of the nonrotating BTZ hole and for its Z_2 quotient, the boundary state is thermal in the expected sense, and its stress-energy reflects the properties of the bulk geometry and suggests a novel definition for the mass of the hole. For the generalised Schwarzschild-AdS hole with a flat horizon of topology R^{d-2}, the boundary stress-energy has a thermal form with energy density proportional to the hole ADM mass, but stress-energy corrections from compactified horizon dimensions cannot be consistently included at least for d=5.Comment: 32 pages. LaTeX with amsfonts, amsmath, amssymb. (v2: References added. v3: Geodesic horizon-crossing clarified in section 2; comparison with quasilocal energy-momentum included in section 4.

    Absolute quantitative proteomics using the total protein approach to identify novel clinical immunohistochemical markers in renal neoplasms

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    PM003/2016).) .. This project utilized the University of Pittsburgh Hillman Cancer Center shared resource facilities (Cancer Genomics Facility and The Health Science Tissue Bank) supported in part by award P30CA047904 (Dr. W. LaFramboise and R. Dhir).Background: Renal neoplasms encompass a variety of malignant and benign tumors, including many with shared characteristics. The diagnosis of these renal neoplasms remains challenging with currently available tools. In this work, we demonstrate the total protein approach (TPA) based on high-resolution mass spectrometry (MS) as a tool to improve the accuracy of renal neoplasm diagnosis. Methods: Frozen tissue biopsies of human renal tissues [clear cell renal cell carcinoma (n = 7), papillary renal cell carcinoma (n = 5), chromophobe renal cell carcinoma (n = 5), and renal oncocytoma (n = 5)] were collected for proteome analysis. Normal adjacent renal tissue (NAT, n = 5) was used as a control. Proteins were extracted and digested using trypsin, and the digested proteomes were analyzed by label-free high-resolution MS (nanoLC-ESI-HR-MS/MS). Quantitative analysis was performed by comparison between protein abundances of tumors and NAT specimens, and the label-free and standard-free TPA was used to obtain absolute protein concentrations. Results: A total of 205 differentially expressed proteins with the potential to distinguish the renal neoplasms were found. Of these proteins, a TPA-based panel of 24, including known and new biomarkers, was selected as the best candidates to differentiate the neoplasms. As proof of concept, the diagnostic potential of PLIN2, TUBB3, LAMP1, and HK1 was validated using semi-quantitative immunohistochemistry with a total of 128 samples assessed on tissue micro-arrays. Conclusions: We demonstrate the utility of combining high-resolution MS and the TPA as potential new diagnostic tool in the pathology of renal neoplasms. A similar TPA approach may be implemented in any cancer study with solid biopsies.publishersversionpublishe

    Nitric Oxide Resistance in Leishmania (Viannia) braziliensis Involves Regulation of Glucose Consumption, Glutathione Metabolism and Abundance of Pentose Phosphate Pathway Enzymes

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    In American Tegumentary Leishmaniasis production of cytokines, reactive oxygen species and nitric oxide (NO) by host macrophages normally lead to parasite death. However, some Leishmania braziliensis strains exhibit natural NO resistance. NO-resistant strains cause more lesions and are frequently more resistant to antimonial treatment than NO-susceptible ones, suggesting that NO-resistant parasites are endowed with specific mechanisms of survival and persistence. To tests this, we analyzed the effect of pro- and antioxidant molecules on the infectivity in vitro of L. braziliensis strains exhibiting polar phenotypes of resistance or susceptibility to NO. In addition, we conducted a comprehensive quantitative mass spectrometry-based proteomics analysis of those parasites. NO-resistant parasites were more infective to peritoneal macrophages, even in the presence of high levels of reactive species. Principal component analysis of protein concentration values clearly differentiated NO-resistant from NO-susceptible parasites, suggesting that there are natural intrinsic differences at molecular level among those strains. Upon NO exposure, NO-resistant parasites rapidly modulated their proteome, increasing their total protein content and glutathione (GSH) metabolism. Furthermore, NO-resistant parasites showed increased glucose analogue uptake, and increased abundance of phosphotransferase and G6PDH after nitrosative challenge, which can contribute to NADPH pool maintenance and fuel the reducing conditions for the recovery of GSH upon NO exposure. Thus, increased glucose consumption and GSH-mediated redox capability may explain the natural resistance of L. braziliensis against NO

    In-depth quantitative proteomics uncovers specie-specific metabolic programs in Leishmania (Viannia) species

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    Author summary Leishmania braziliensis,L.panamensis, andL.guyanensisare responsible for most of the cases of tegumentary leishmaniasis (TL) in the Americas. These species are associated with a variety of clinical manifestations of TL ranging from self-healing localized cutaneous lesions to disseminated and mucocutaneous presentations that may result in severe oropharyngeal mutilation. Here, we report a comprehensive quantitative comparison of the proteome of those species. Assessment of absolute titers of similar to 7000 proteins revealed a very clear differentiation among them. Significant differences in energy metabolism, membrane proteins, transporters, and lipids are contributing for species-specific traits and provide rich substrate for exploring new molecules for diagnosing purposes. Leishmaniaspecies are responsible for a broad spectrum of diseases, denominated Leishmaniasis, affecting over 12 million people worldwide. During the last decade, there have been impressive efforts for sequencing the genome of most of the pathogenicLeishmaniaspp. as well as hundreds of strains, but large-scale proteomics analyses did not follow these achievements and theLeishmaniaproteome remained mostly uncharacterized. Here, we report a comprehensive comparative study of the proteomes of strains representingL.braziliensis,L.panamensisandL.guyanensisspecies. Proteins extracted by SDS-mediated lysis were processed following the multi-enzyme digestion-filter aided sample preparation (FASP) procedure and analysed by high accuracy mass spectrometry. "Total Protein Approach" and "Proteomic Ruler" were applied for absolute quantification of proteins. Principal component analysis demonstrated very high reproducibility among biological replicates and a very clear differentiation of the three species. Our dataset comprises near 7000 proteins, representing the most completeLeishmaniaproteome yet known, and provides a comprehensive quantitative picture of the proteomes of the three species in terms of protein concentration and copy numbers. Analysis of the abundance of proteins from the major energy metabolic processes allow us to highlight remarkably differences among the species and suggest that these parasites depend on distinct energy substrates to obtain ATP. WhereasL.braziliensisrelies the more on glycolysis,L.panamensisandL.guyanensisseem to depend mainly on mitochondrial respiration. These results were confirmed by biochemical assays showing opposite profiles for glucose uptake and O(2)consumption in these species. In addition, we provide quantitative data about different membrane proteins, transporters, and lipids, all of which contribute for significant species-specific differences and provide rich substrate for explore new molecules for diagnosing purposes. Data are available via ProteomeXchange with identifier PXD017696

    Strange meson production in Al+Al collisions at 1.9A GeV

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    The production of K+^+, K^- and φ\varphi(1020) mesons is studied in Al+Al collisions at a beam energy of 1.9A GeV which is close or below the production threshold in NN reactions. Inverse slopes, anisotropy parameters, and total emission yields of K±^{\pm} mesons are obtained. A comparison of the ratio of kinetic energy distributions of K^- and K+^+ mesons to the HSD transport model calculations suggests that the inclusion of the in-medium modifications of kaon properties is necessary to reproduce the ratio. The inverse slope and total yield of ϕ\phi mesons are deduced. The contribution to K^- production from ϕ\phi meson decays is found to be [17 ±\pm 3 (stat) 7+2^{+2}_{-7} (syst)] %. The results are in line with previous K±^{\pm} and ϕ\phi data obtained for different colliding systems at similar incident beam energies.Comment: 16 pages, 11 figure

    Centrality dependence of subthreshold ϕ\phi meson production in Ni+Ni collisions at 1.9A GeV

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    We analysed the ϕ\phi meson production in central Ni+Ni collisions at the beam kinetic energy of 1.93A GeV with the FOPI spectrometer and found the production probability per event of [8.6 ± 1.6 (stat)±1.5 (syst)]×104[8.6 ~\pm~ 1.6 ~(\text{stat}) \pm 1.5 ~(\text{syst})] \times 10^{-4}. This new data point allows for the first time to inspect the centrality dependence of the subthreshold ϕ\phi meson production in heavy-ion collisions. The rise of ϕ\phi meson multiplicity per event with mean number of participants can be parameterized by the power function with exponent α=1.8±0.6\alpha = 1.8 \pm 0.6. The ratio of ϕ\phi to K\text{K}^- production yields seems not to depend within the experimental uncertainties on the collision centrality, and the average of measured values was found to be 0.36±0.050.36 \pm 0.05.Comment: 9 pages, 5 figure
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