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The production of surfactant-assisted metallic nanoparticles of TbCu has been achieved by the combination of high-energy ball milling in tungsten carbide containers and the use of oleic acid (CHO) and heptane (CH). The alloys were first produced in bulk pellets by arc melting and subsequently milled for only 2 and 5 h in oleic acid (15 and 30% mass weight). The powders consist of an ensemble of nanoparticles with a TbCu lattice cell volume of ≈215 Å, an average particle diameter between 9 and 12 nm and inhomogeneous lattice strain of 0.2-0.4%, as deduced from X-ray diffraction data. The nanometric sizes of the crystals with defined lattice planes are close to those obtained by transmission electron microscopy. Raman spectroscopy shows the existence of inelastic peaks between 1000 and 1650 cm, a characteristic of CHO. The magnetisation shows a peak at the antiferromagnetic-paramagnetic transition with Néel temperatures around 48 K (below that of bulk alloy) and a distinctive metamagnetic transition at 5 K up to 40 K. The Curie-Weiss behaviour above the transition reveals effective Bohr magneton numbers (≈9.1-9.9 μ) which are close to what is expected for the free Tb ion using Hund's rules. The metamagnetic transition is slightly augmented with respect to the bulk value, reaching H = 24.5 kOe by the combined effect of the size reduction and the lattice strain increase and the increase of magnetic disorder. At low temperatures, there is irreversibility as a result of the existing magnetic disorder. The moment relaxation follows an Arrhenius model with uncompensated Tb moments, with activation energies between 295 and 326 K and pre-exponential factors between 10 and 10 s. The results are interpreted as a consequence of the existence of a diamagnetic surfactant which drastically decreases the magnetic coupling between interparticle moments. [ABSTRACT FROM AUTHOR]

A chemical characterization of diesel and hydrotreated vegetable oil (HVO) soot has been developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) before and after the reaction with different probe gases. Samples were generated under combustion conditions corresponding to an urban operation mode of a diesel engine and were reacted with probe gas-phase molecules in a Knudsen flow reactor. Specifically, NHOH, O and NO were used as reactants (probes) and selected according to their reactivities towards specific functional groups on the sample surface. Samples of previously ground soot were diluted with KBr and were introduced in a DRIFTS accessory. A comparison between unreacted and reacted soot samples was made in order to establish chemical changes on the soot surface upon reaction. It was concluded that the interface of diesel and HVO soot before reaction mainly consists polycyclic aromatic hydrocarbons, nitro and carbonyl compounds, as well as ether functionalities. The main difference between both soot samples was observed in the band of the C=O groups that in diesel soot was observed at 1719 cm but not in HVO soot. After reaction with probe gases, it was found that nitro compounds remain on the soot surface, that the degree of unsaturation decreases for reacted samples, and that new spectral bands such as hydroxyl groups are observed. [ABSTRACT FROM AUTHOR]

A 2.0 L, 4-cylinder, turbocharged, common rail diesel engine was used for generating soot samples. Three fuels were tested: a 'first fill' diesel fuel, a gas-to-liquid fuel (GTL) and a hydrotreated fuel derived from vegetable oils (HVO). A stationary low-load operating mode (1667 rpm and 78 Nm) was selected for testing, and some modifications in the injection process (strategy, timing and pressure) were evaluated experimentally to assess their influence in the soot reactivity. The collected soot samples were characterized using a thermogravimetric analyzer (TGA), a differential scanning calorimeter (DSC), a diffuse reflectance infrared Fourier transform spectrometer (DRIFTS) and a surface area analyzer. All techniques anticipated that HVO and GTL soot samples are more reactive (i.e. show higher potential to be oxidized at lower temperatures leading to more efficient regeneration processes in a Diesel Particle Filter - DPF) compared to diesel soot. Additionally, the four characterization techniques showed the same tendencies when analyzing the effect of the engine operating parameters. In view of the results, the paraffinic fuels - HVO and GTL - here tested confirm their promising perspective for future use in automotive diesel engines, while some guides are proposed to enhance the soot reactivity via calibration of engine operating parameters. [ABSTRACT FROM AUTHOR]

A case of CLL with two different cellular populations is reported. A 50-year-old man was evaluated for persistent absolute lymphocytosis. A peripheral blood smear revealed numerous small lymphocytes (83% of white blood cells counted). Frequent Grumpecht shadows were present, too. On bone marrow aspirate smears lymphocytes comprised 85% of the total cells counted, and the bone marrow biopsy showed a mixed nodular-interstitial infiltration pattern. The immunophenotypic study showed two different leukemic populations. The first one (comprising 79% leukemic cells) was CD5+, CD19+, CD10-, CD20+, CD18-, CD22-, CD23+ +, lambda dim, and FMC7-. The second population (comprising 21% leukemic cells) was CD5+, CD19+, CD10-, CD20+, CD18+, CD22+, CD23+, lambda+ +, and FMC7+. Gene rearrangement studies detected the germline and one rearranged band in Jk blot with each restriction endonuclease. In the Jh blot the germline and two rearranged bands were detected with EcoRI and BamHI and three rearranged bands with HindIII. The JBI/JBII blot detected only the germline band. The detection of three rearranged bands was interpreted as evidence of the presence of at least two monoclonal populations of cells with the same light chain restriction. [ABSTRACT FROM AUTHOR]

Herein we report on synthetic iron-intercalated vermiculites prepared from a Mg-vermiculite mineral from Santa Olalla, Huelva, Spain, by means of an ion exchange process from aqueous solutions of FeCl and FeCl. Thermogravimetric, X-ray diffraction, magnetic susceptibility and Mössbauer spectral studies have been used to characterize the synthetic iron-intercalated vermiculites. The results suggest that the intercalation process employed induces modifications in both the interlayer spacing and in the octahedral sheet; the disordered structure of the Mg-vermiculite mineral is not altered. The presence of solvated Fe(HO) ions has been shown by the Mössbauer spectroscopy. No magnetic order has been observed between 2 and 300 K neither in the Mg-vermiculite mineral nor in the two synthetic iron-intercalated vermiculites. [ABSTRACT FROM AUTHOR]

The ground state of the strongly correlated electron CeNi1-xCux compounds has been investigated by means of neutron scattering experiments. Thus, magnetic diffraction was performed for compounds showing long-range magnetic order ( x > 0.2). An evolution from a collinear ferromagnetic structure for x =0.6 to a simple antiferromagnetic one for CeCu takes place through some more complex magnetic structures for intermediate compositions. The magnetic moments are continuously reduced when the Ni content increases reflecting the progressive enhancement of the Kondo screening. The large reduction found for x =0.6 compound is discussed and the existence of a spin glass like component of the magnetic moment cannot be discarded. From the quasielastic spectra, we have obtained the Kondo temperatures which are close to the magnetic ordering ones. The quasielastic line-width evolves from a linear temperature dependence to a T 1/2 behaviour when approaching the non-magnetic limit. Then, this system provides an interesting example for the evolution of unstable 4 f shell relaxation regimes when modifying the hybridisation strength. [ABSTRACT FROM AUTHOR]

The structure of the South Powell Ridge (SPR), separating the Late Cenozoic ocean-floored Powell Basin and the Mesozoic Weddell Sea domain, is revealed by multichannel seismic data. The SPR appears as a basement high, bounded northward by transtensional faults and by normal and major reverse faults to the south. These margin features seem to be linked to the Powell Basin southern strike-slip margin and to the Jane Arc paleotrench, respectively. We suggest the ridge evolved from the Antarctic Peninsula passive margin to become the deformational front of the Scotia/Antarctica Plate boundary, later being welded to the Antarctic Plate. [ABSTRACT FROM AUTHOR]

Abstract. A variety of T, B and natural killer (NK) cell subsets defined by surface markers were analyzed by double immunofluorescence flow cytometry in the peripheral blood of patients following autologous bone marrow transplantation (ABMT, n=14), autologous peripheral blood stem cell transplantation (PBSCT, n=10) and allogeneic bone marrow transplantation (allo-BMT, n=6). Patients following ABMT were divided in 2 groups, those who did not received G-CSF post-transplant (ABMT, n=6) and those who did (ABMT+G, n=8). All patients following PBSCT or allo BMT received G-CSF. In all the groups prolonged significant decreases with respect to normal numbers were observed for the T CD3+, CD2+ and CD25+ subsets, more profound for the CD4+ subset but less for the CD8+ subset, especially following PBSCT (only decreased at 1 month). A significant expansion of the CD3+CD57+ and CD8+CD57+ phenotypes was noticed between 9 and 12 months following ABMT, the group of longer follow-up. Long-lasting expansion of the NK-like CD3+CD56+ and CD3+CD16+ subsets was also observed. The B CD19+ and CD20+ subsets had a significant overexpression from 4 months after ABMT, showing a normally balanced Igk+ : Ig1+ ratio. Concordantly, the HLA-DR+ and HLA-DQ+ subsets showed significant increases. The NK CD56+ and CD16+ subsets had a faster recovery than the T or B subsets in all the groups. However, the CD3-CD56+, CD3-CD16+, CD16+CD56+, CD3-CD8+, and especially the CD3-CD57+, CD16+CD57+, and CD56+CD57+ subsets had a slower recovery than the global CD56+, CD16+, or CD57+ subsets. The biological and clinical implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

We present the evolution of the magnetic structures of TbPt and TbPt[sub 0.6]Cu[sub 0.4] under pressures up to 65 kbar. The first compound is ferromagnetic non-collinear -C[sub x]F[sub z], while in the Cu-diluted one an almost antiferromagnetic (AF) behaviour appears, corresponding to a complex structure in which the -C[sub x]F[sub z] phase coexists with an incommensurate one. We have found that pressure favours a general AF behaviour, which manifests as a clear increasing of the AF component in the non-collinear phase, and in the evolution to a pure AF arrangement of the moments in the unit cell for the incommensurate one. [ABSTRACT FROM AUTHOR]