Optical properties of Nd-doped Ca3(VO4)2 single crystal fiber

Optical absorption and photoluminescence of Ca₃(VO₄)₂ single crystal grown by a floating-zone technique and containing Nd³⁺ ions were investigated. High absorption coefficients and broadening of most absorption bands are present at 300 K, while substructures in some of the same bands can be evidenced at 12 K. Most features of measured spectra are characteristic of random occupation of more than a single Ca²⁺ site by the Nd³⁺ ion and of distortions provoked by different charge compensation mechanisms involving oxygen vacancies promotion in the crystal lattice. Nd³⁺ optical properties were studied by using the Judd-Ofelt theory to calculate the spectral parameters relevant for laser applications.     

Interdisciplinary approach to functional voice disorders: the psychiatrist''s role

The Trichuris muris-mouse model of intestinal helminth infection provides a convenient system to examine the immune mechanisms operating during acute and chronic infection. Particular subsets of helper T lymphocytes (CD4+Th cells) play an important role in regulating infection via the secretion of distinct groups of cytokines. Reciprocal activation of Th cell subsets is associated with either expulsion of the parasites from the intestine (Th2 cells) or chronic infection (Th1 cells). In vivo neutralization experiments using anti-cytokine monoclonal antibodies show that critical cytokines are involved, with interferon-gamma playing an important role in the establishment of chronic trichuriasis and interleukin-4 in expulsion of the parasite from the gut. This model has provided clear evidence of a crucial role for distinct cytokines in mediating host protection against intestinal helminth infection and that manipulation of the immune response through the Th cell-cytokine axis can benefit either the host or the parasite. As such, the T. muris model is poised to generate important new data relevant not only to intestinal helminthiasis but to the wider field of parasite immunity and infection in general.     

Adaptive covariate acquisition for minimizing total cost of classification

Machine Learning - In some applications, acquiring covariates comes at a cost which is not negligible. For example in the medical domain, in order to classify whether a patient has diabetes or not,...     

Influence of the composition of the binder and the carbonation on the zeta potential values of hardened cementitious materials

Electroosmotic experiments have been carried out on eight different mixes of hardened cementitious matrixes including concrete, mortar and pastes, different types of binders, carbonated and non-carbonated specimens and different test conditions. From these trials, the zeta potential values have been determined and the optimum experimental parameters and devices have been established. In addition, the influence of the composition of the binder on the zeta potential has been quantified indicating that higher amounts of Al₂O₃ in the binder lead to higher positive values of zeta potential, while the SiO₂ acts just on the opposite side. This has been explained in terms of the different i.e.p. (isoelectric point) for both oxides. Concerning the influence of carbonation, it increases the absolute value of the zeta potential toward more negative values; this behaviour has been attributed to the influence of the specifically adsorbed Ca²⁺ in the negative sites of the surface in the non-carbonated samples.     

Aspects of moisture kinetics of coal bottom ash in concrete

The moisture kinetics aspects of composite granular material samples composed of natural sand and bottom ash (BA) from thermoelectric power stations and the use of this material in the production of durable concretes, in relation to water transport, are here discussed. The evaluations of the phenomenon of water absorption by capillarity and the loss of water through air drying until hygroscopic equilibrium, were carried out in accordance with classic procedures found in the literature and also newly developed procedures. The results showed that due to the high porosity of BA, the water absorption by capillarity along with the absorption velocity were higher in the compositions with greater BA content. The values for moisture equilibrium from air drying, absorption from capillarity and sorptivity obtained in the hygroscopic equilibrium tests, carried out on the same samples after absorption, were also higher in the samples with BA. These samples also requited a longer drying time.     

Round-Robin Test on methods for determining chloride transport parameters in concrete

This paper presents the results of a Round-Robin Test on methods for determining chloride transport parameters in concrete, carried out by the Technical Committee TC 178-TMC: “Testing and Modelling Chloride Penetration in Concrete” in which 27 different laboratories around the world have participated, using 13 different methods, in triplicate specimens, for 4 different mixes of concrete cast with different binders. Four different groups of methods have been tested: Natural diffusion methods (D), Migration methods (M), Resistivity methods (R) and Colourimetric methods (C). The statistical treatment of the data has been carried out according to the International Standard ISO 5725-2:1994 for the determination of the accuracy (trueness and precision) of measurement methods and results. Part 2: Basic method for the determination of the repeatability and reproducibility of a standard measurement method. In order to make an evaluation of these methods, four indicators have been identified and within each of them, several sub-indicators have been assigned. According to this system of classification, the methods have been classified following each indicator (trueness, precision, relevance and convenience), and also globally, by assigning different factors of importance, F.I., to the different indicators.     

Production of anti-erythrocyte antibodies by leukemic and nonleukemic B cells in chronic lymphocytic leukemia patients

We have assessed the specificity of antibodies from the leukemic B cells of five patients with both chronic lymphocytic leukemia and autoimmune hemolytic anemia (CLL-AHA). Leukemic cells from one patient displayed surface immunoglobulin with heavy and light chain isotypes identical to that of the patient's anti-red blood cell (RBC) antibodies, and the leukemic cells secreted antibodies in vitro with anti-RBC activity. However, in the remaining patients, the leukemic cells displayed surface immunoglobulin with light chain isotypes different from that of the patient's anti-RBC antibodies and secreted antibodies in vitro with no detectable anti-RBC activity. Thus, there are two distinct classes of CLL-AHA patients, differentiated by the presence or absence of an anti-RBC antibody-producing leukemic B cell clone. The apparent heterogeneity in the source of pathogenic anti-RBC antibodies may impact the treatment response of the two classes of CLL-AHA patients.