Accuracy in Rietveld quantitative phase analysis: a comparative study of strictly monochromatic Mo and Cu radiations.

This study reports 78 Rietveld quantitative phase analyses using Cu Kα1, Mo Kα1 and synchrotron radiations. Synchrotron powder diffraction has been used to validate the most challenging analyses. From the results for three series with increasing contents of an analyte (an inorganic crystalline phase, an organic crystalline phase and a glass), it is inferred that Rietveld analyses from high-energy Mo Kα1 radiation have slightly better accuracies than those obtained from Cu Kα1 radiation. This behaviour has been established from the results of the calibration graphics obtained through the spiking method and also from Kullback-Leibler distance statistic studies. This outcome is explained, in spite of the lower diffraction power for Mo radiation when compared to Cu radiation, as arising because of the larger volume tested with Mo and also because higher energy allows one to record patterns with fewer systematic errors. The limit of detection (LoD) and limit of quantification (LoQ) have also been established for the studied series. For similar recording times, the LoDs in Cu patterns, ∼0.2 wt%, are slightly lower than those derived from Mo patterns, ∼0.3 wt%. The LoQ for a well crystallized inorganic phase using laboratory powder diffraction was established to be close to 0.10 wt% in stable fits with good precision. However, the accuracy of these analyses was poor with relative errors near to 100%. Only contents higher than 1.0 wt% yielded analyses with relative errors lower than 20%.

Primer reporte de queratitis por Nocardia brasiliensis en Paraguay / Queratitis due to Nocardia brasiliensis. First report in Paraguay

La queratitis producida por Nocardia spp es raramente reportada en el mundo por lo que su incidencia no está aún bien establecida. En el presente estudio se reporta el primer caso de queratitis por Nocardia brasiliensis en Paraguay en un paciente de sexo masculino, de profesión jardinero, procedente de la ciudad de Asunción, y con antecedente de traumatismo con rama de arbusto quince días antes de la consulta. El paciente acude al servicio de Oftalmología del Hospital de Clínicas, debido a ojo rojo, agudeza visual disminuida e intenso dolor en el ojo izquierdo con una semana de evolución. Se realiza tratamiento con la aplicación de colirio reforzado de gentamicina 14 mg/ml y cefazolina 50 mg/ml, cada una hora, observándose mejoría de los síntomas y de la agudeza visual a los 10 días de seguimiento. La evolución clínica en queratitis a Nocardia spp es buena siempre que el diagnóstico etiológico se realice sin demora y correctamente. Es muy importante diferenciar los bordes de las lesiones de la úlcera de córnea producidas por hongos, bacterias filamentosas y otras bacterias, además considerar la presencia de lesiones satélites

Zirconia-MWCNT nanocomposites for biomedical applications obtained by colloidal processing.

Zirconia ceramics are widely used as femoral heads, but case studies show that delayed failure can occur in vivo due to crack propagation. The addition of carbon nanotubes (CNT) is aimed to avoid the slow crack propagation and to enhance the toughness of the ceramic material used for prostheses. However, to really enhance the mechanical properties of the material it is necessary to achieve a uniform distribution of the CNT in the zirconia matrix. Colloidal processing has demonstrated to be suitable for obtaining ceramic-based composites with homogeneous distribution of the phases and high green density. This work compares the colloidal behavior of the as-received multi wall carbon nanotubes (ar-MWCNT) and the partially coated MWCNT (pc-MWCNT) when immersed in a nanozirconia matrix. With pc-MWCNT an improvement in the dispersion is proved. Moreover, the sintered samples that contain pc-MWCNT show higher density, lower grain size, improved toughness and enhanced hardness under the same sintering cycle when compared to the samples with ar-MWCNT.

Human immunodeficiency virus infection and nutritional status in female drug addicts undergoing detoxification: anthropometric and immunologic assessments.

To clarify the interrelations among drug abuse, malnutrition, and immunosuppression, the effects of human immunodeficiency virus (HIV) infection on the nutritional status of 17 noninfected and 19 HIV-infected asymptomatic female drug addicts undergoing detoxification were evaluated by measuring anthropometric and immunologic indexes. Anthropometric measurements were normal in both groups as a result of weight gain (approximately 10 kg) in every patient after the detoxification period. Leukocyte and lymphocyte values and CD2 lymphocyte subset counts were also similar in both groups. CD4 counts (P = 0.04) and the ratio of CD4 to CD8 cells (P = 0.6 x 10(-4)) were lower whereas CD8 counts (P = 0.003) were higher in the HIV-infected than in the noninfected group. Responses to a delayed-hypersensitivity skin test were below normal in both groups but significantly more so in the HIV-positive group (P = 0.05). CD19 counts were lower (P = 0.02) and values for serum immunoglobulins G and M were higher (51% and 37%, respectively) in the HIV-infected females than in the noninfected women. These results may suggest that despite anthropometric recovery, the HIV-infected women had depleted immune function, resulting not only from HIV infection but also from the subclinical malnutrition triggered by previous drug addiction.

Effects of human immunodeficiency virus infection and detoxification time on anthropometric measurements and dietary intake of male drug addicts.

Anthropometric measurements and dietary intakes of male drug addicts (n = 62), infected (n = 23) or not infected (n = 39) with human immunodeficiency virus (HIV), who underwent two phases of detoxification (P1:15 d to 1 mo and P2: 5-6 mo) were assessed. Body weight, weight gain during detoxification, height, body mass index, and ideal body weight were measured. A prospective food-record questionnaire was compiled and energy and nutrient contents of ingested food were determined. Food intakes were compared with dietary recommendations for the Spanish population. At the time of the study, all patients had substantial weight gains, mostly in P1. Nutrient consumption was lower in P2 (energy, protein, and lipids) and in groups not infected with HIV. In P2, lipid intake was higher in the HIV-positive than in the HIV-negative group (P < 0.05, Student's t test). Moreover, an interactive effect of HIV by phase was shown for lipid intake (P = 0.04, two-way analysis of variance). Magnesium, folate, and vitamin E intakes were lower than recommended in nearly all patients. Energy, zinc, riboflavin, and vitamin B-6 intakes were lower than recommended or were borderline. HIV infection did not have a negative effect on anthropometric measurements or on nutrient intakes. The anthropometric assessment may suggest an adequate recovery of the indexes measured in all patients, which principally took place during P1. Measurement of nutrient intakes showed certain imbalances and deficits that should be corrected.

Nutritional status and immunocompetence in eating disorders. A comparative study.

Nutritional status and immunocompetence were evaluated in 26 patients suffering from anorexia nervosa (AN) (n = 16) or bulimia nervosa (BN) (n = 10) in comparison with a control group (n = 22). Body mass index (BMI) was lower in all patients than in controls, AN patients having the lowest values. Slight leukopenia together with relative lymphocytosis was shown in both AN and BN. The CD4/CD8 ratio was low in all patients, but more so for BN patients, although cell-mediated immune function was impaired to the same extent for both eating disorders. The complement system appeared to be damaged in all the patients in comparison with controls. These results may mean that the nutritional status of both syndromes was different. Although anthropometric measurements in the BN group may suggest a more acceptable nutritional status, immunological parameters were shown to be depleted at the same level as the AN group and even more impaired when judged by the lower CD4/CD8 values.

Evaluation of immunocompetence and nutritional status in patients with bulimia nervosa.

Nutritional status of patients suffering from bulimia nervosa was evaluated by anthropometric, hematological, and immunological parameters in comparison with a healthy control group. Anthropometry showed no signs of malnutrition in either group. Bulimic patients showed a significant decrease in most of the routine clinical indexes related to red blood cells. Lymphocyte subsets CD2 and CD4 in bulimic patients were lower than in controls, whereas CD8 remained unmodified, leading to a lower CD4:CD8 in bulimic patients. The decreases in CD2 and CD4 numbers might be linked to an impaired cell-mediated immune function, as evaluated by the response to skin tests. The B lymphocyte subset was increased in the bulimic group. Innate immunity was impaired in the bulimic patients. Although anthropometric and most of the routine clinical parameters were within the normal range, these results might suggest that the depleted immune function accounts for a subclinical malnutrition status in bulimic patients.