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Remarkable electrical properties in the hard magnetic materials M hexaferrites have been reported in recent years. To evidence these properties, synthesis processes involving heat treatments at high temperatures (1300 °C) in an oxygen atmosphere have usually been necessary. In this work, using the chemical coprecipitation route, SrFe12O19 hexaferrite powders were synthesized with different Sr/Fe stoichiometric ratios (1/12, 1/11, 1/10.8). These powders were thermally treated between 830 and 1005 °C in air. In correspondence with the nanometric particle sizes of the synthesized powders, high values of saturation magnetization, Ms (~ 72 emu g−1), and a maximum coercive field, iHc of 5.9 kOe, were obtained for SrM 1/10.8. The samples with a ratio of 1/10.8 treated at 1005 °C for 2 h in air did not reveal spurious phases, so electrical loops at low fields were performed, which showed an incipient electrical ordering. To favor this aspect, the powders were reheated at 1100 °C for 2 h in air. The polarization vs electrical field curves showed remanent polarization and coercivity values comparable to those previously reported for heat treatments at more elevated temperatures in the presence of oxygen. [ABSTRACT FROM AUTHOR]

Bi0.90Ba0.10Fe0.90Ti0.10O3 and Bi0.90Ba0.10Fe0.88Cr0.02Ti0.10O3 multiferroic ceramics were prepared, in order to evaluate the chrome influence on the physical properties of Ba2+ and Ti4+ co-doped BiFeO3 system. The structural properties revealed, at room temperature, a rhombohedral (R3c) ferroelectric phase for the studied compositions. The dielectric analysis was carried out in a wide temperature and frequency ranges. The dielectric results have shown a clear magneto-electric coupling, which is associated to the presence of a dielectric anomaly around the antiferromagnetic-paramagnetic transition temperature. Additionally, the Cr3+ ions play an important role decreasing the electrical conductivity of the studied compositions. The doping element has also shown an important influence on the magnetic hysteresis results. [ABSTRACT FROM AUTHOR]

Some patients with epithelial-cell cancers develop leptomeningeal carcinomatosis (LC), a severe complication difficult to diagnose and with an adverse prognosis. This study explores the contribution of flow cytometry immunophenotyping (FCI) to the diagnosis and prognosis of LC. Cerebrospinal fluid (CSF) samples from patients diagnosed with LC were studied using FCI. Expression of the epithelial-cell adhesion molecule (EpCAM) was the criterion used to identify the epithelial cells. To test the diagnostic precision, 144 patients (94 diagnosed with LC) were included. The prognostic value of FCI was evaluated in 72 patients diagnosed with LC and eligible for therapy. Compared with cytology, FCI showed greater sensitivity and negative predictive value (79.79 vs. 50 %; 68.85 vs. 51.55 %, respectively), but lower specificity and positive predictive value (84 vs. 100 %; 90.36 vs. 100 %, respectively). The multivariate analysis revealed that the percentage of CSF EpCAM+ cells predicted an increased risk of death (HR: 1.012, 95 % CI 1.000-1.023; p = 0.041). A cut-off value of 8 % EpCAM+ cells in the CSF distinguished two groups of patients with statistically significant differences in overall survival (OS) (p = 0.018). This cut-off value kept its statistical significance regardless of the absolute CSF cell-count. The FCI study of the CSF improved the sensitivity for diagnosing LC, but refinement of the technique is needed to improve specificity. Furthermore, quantification of CSF EpCAM+ cells was revealed to be an independent prognostic factor for OS in patients with LC eligible for therapy. An 8 % cut-off value contributed to predicting clinical evolution before initiation of therapy. [ABSTRACT FROM AUTHOR]

Metalorganic decomposition and coprecipitation from aqueous solution have been used to synthesize thin film and bulk bismuth ferrite (BiFeO) with perovskite structure. X-ray diffraction, thermomagnetic analysis, and scanning electron microscopy were used to analyze the material and identify spurious phases. The magnetic characterization at room temperature revealed remarkable differences between bulk and film samples. The results show that in BiFeO bulk ceramics, spontaneous magnetization is not observed at room temperature. Nevertheless, in thin films, a well-defined ferromagnetic behavior is observed at room temperature. Dielectric measurements taken on ceramic samples present an anomaly around 643 K that can be associated with the Néel temperature. [ABSTRACT FROM AUTHOR]

Relative water content in Actinidia deliciosa explants cultured in the presence of three benzyladenine (Ba) concentrations (4.4, 44, and 440 μM) during different incubation periods were measured at different stages of the micropropagation process. Ba incubation period during the multiplication phase determined the quality of A. deliciosa plantlets and affected both water content or retention capacity. Therefore, exogenous cytokinin application affected the quality and survival of plantlets in ex vitro conditions. In this sense, when 4.4 μM Ba concentration was used, values higher than 20% for the dry weight/water saturated weight ratio at the end of the rooting phase can be indicative of low plantlet growth. Besides, the exposure period to cytokinins is of more affect than concentration. [ABSTRACT FROM AUTHOR]

Neurological disorders are common in HIV-infected patients. Central nervous system (CNS) lymphoma should always be considered because it is an important cause of morbidity and mortality.To investigate the clinical utility of flow cytometry immunophenotyping (FCI) in diagnosing or discarding leptomeningeal involvement in HIV-infected patients and to compare its sensitivity with that of conventional cytological methods.Fifty-six cerebrospinal fluid (CSF) samples from 29 HIV-infected patients were independently evaluated by flow cytometry and cytology. The description of an aberrant immunophenotype was the criterion used to define the malignant nature of any CSF cell population.FCI and cytology gave concordant results for 48 of the 56 CSF samples studied: 37 were negative for malignancy and 11 had evidence of CNS lymphoma. Discordant results were obtained for eight CSF samples, and the accuracy of the FCI findings could be demonstrated for four CSF samples described as positive for malignancy according to the FCI criteria.A high level of agreement was found between the results obtained using the two methods, but FCI gave at least 25% higher sensitivity than conventional cytomorphological methods for the detection of malignant cells. This advantage suggests that, in case of negative flow cytometry results, disorders other than non-Hodgkin's lymphoma should be strongly considered. [ABSTRACT FROM AUTHOR]

Magnetic and Mö ssbauer measurements have been performed on polycrystalline samples of Ga substituted M-type hexagonal ferrites having compositions PbFe12− xGa xO19 (0 < x < 11). The saturation magnetisation (σS) at 0 K falls with increasing x, from 20 μB for x = 0 to 4.32 μB for x = 6. The Curie temperature tends to zero at x ≈ 9, indicating that the compounds with x > 9 are paramagnetic at all temperatures. The magnetic moments of the non substituted Fe3+ ions in the spin-up predominant sublattice do not have the same temperature dependence, because of the presence of non magnetic Ga3+ ions in the neighbouring lattice sites. For x < 3, the Mössbauer data show that there is no significant deviation from collinear magnetic order. The decrease of σS(0) for x < 3 agrees with the collinear model and the distribution of gallium in all the five available sublattices. At x > 3, the faster decline of the saturation magnetisation can be attributed to the onset of non collinear magnetic order. [ABSTRACT FROM AUTHOR]

Central nervous system (CNS) leukaemia is still a matter of debate and new technologies are required to improve the classic morphological definition. One hundred and sixty-eight cerebrospinal fluid (CSF) samples from 31 patients with acute leukaemia were analysed by flow cytometry and conventional cytology. Concordant positive and negative findings were found in 158 samples but 10 produced discrepant results. Cytology seemed to offer more precise information in one CSF sample and flow cytometric accuracy could be demonstrated in five samples. We conclude that flow cytometry is of great help in confirming CNS leukaemia and eliminating other conditions. Therefore, leukaemic patients can benefit from double cytological and flow cytometric CSF studies. [ABSTRACT FROM AUTHOR]

Magnetic and Mössbauer measurements have been performed on polycrystalline substituted M-type hexagonal ferrites of compositions PbFe12− xSc xO19 ( x = 0, 0.5, 1, 1.5) and PbFe12− xIn xO19 ( x = 0, 1, 2). The substitution of the Fe3+ by Sc3+ and In3+ ions perturbs the axial magnetic order giving rise to angled magnetic structures. From the values of the quadrupole splitting of the Fe57 14.4 keV level, measured above and below the Curie temperatures, the angle between the magnetic moment of the Fe3+ ions in various sublattices and the hexagonal c-axis have been deduced. At 77 K the measured angles do not exceed 20° and depending on x are different for different sublattices. The dependence of x on the saturation magnetisation at 0 K, expressed in Bohr magnetons, differs markedly in Sc and In containing compounds, partly due to the different substitution probability of iron in the spin up and spin down sublattices, and also due to the different spin canting angles. [ABSTRACT FROM AUTHOR]

Summary. Transgenic plants represent an inexpensive alternative to classical fermentation systems for production of recombinant subunit vaccines. Transgenic potato plants were created that express the N-terminal domain of the glycoprotein S (N-gS) from Transmissible gastroenteritis coronavirus (TGEV), containing the major antigenic sites of the protein. Extracts from potato tubers expressing N-gS were inoculated intraperitoneally to mice, and the vaccinated mice developed serum IgG specific for TGEV. Furthermore, when potato tubers expressing N-gS were fed directly to mice, they developed serum antibodies specific for gS protein, demonstrating the oral immunogenicity of the plant derived spike protein from TGEV. [ABSTRACT FROM AUTHOR]