RESUMEN
Ni- and Ru-based catalytic pellets supported on commercial γ-Al2O3 pellets modified with magnesium oxide have been prepared for application in the catalytic conversion of ethanol into butanol. MgO/γ-Al2O3 pellets with or without added metals have been characterized by XRD, SEM/EDX, TGA, N2 physisorption, H2 TPR, and CO2 TPD in order to investigate the effect of MgO coverage and metal distribution on the surface and red-ox properties of the materials and, in turn, their effects on the catalytic performance. The conversion of ethanol into butanol has been investigated in a continuous flow reactor at 350-400 °C under diluted conditions (3% ethanol) in order to rank the different catalytic pellets and identify the best formulations and preparation procedures via a comparison with powder catalysts previously proposed in the literature with similar compositions. Results show enhanced catalytic performance for MgO-covered alumina pellets with respect to a pure MgO powder catalyst in spite of the lower MgO load. A significant further positive effect is found when Ni or Ru enters a solid solution with MgO.
RESUMEN
Results of the indirect antiglobulin test (IAT) potentiated by the addition of polyethylene glycol (PEG) were compared with those of the IAT performed with bovine serum albumin (BSA). This retrospective study, which encompasses 3 years, confirms that use of PEG-IAT increases the rate of detection of clinically significant red cell (RBC) antibodies, decreases the detection of insignificant antibodies, reduces the need to use other serologic enhancement techniques (such as enzyme modification of RBCs), and has a positive impact on the laboratory's workload. These advantages are provided with no diminution in the quality of service provided by the blood bank.
Asunto(s)
Prueba de Coombs/métodos , Polietilenglicoles , Anticuerpos/análisis , Bancos de Sangre , Estudios de Evaluación como Asunto , Humanos , Sistema del Grupo Sanguíneo de Kidd/inmunología , Antígenos del Grupo Sanguíneo de Lewis/inmunología , Sistema del Grupo Sanguíneo Rh-Hr/inmunología , Albúmina Sérica BovinaRESUMEN
PEG3350, a linear polymer of ethylene glycol, was evaluated as a potentiator of the indirect antiglobulin test (IAGT). The polymer enhances the avidity and affinity of clinically significant red cell alloantibodies than those obtained with bovine serum albumin (BSA). The sensitivity and specificity of the PEG-mediated reactions were superior to those obtained with BSA. Subpopulations of red cells, such as those encountered with fetomaternal hemorrhages, were detected at lower concentrations with PEG than with BSA using the microscopic Du test. The superiority of the PEG reaction, its simplicity, and the reagent's relatively low cost make substitution of the polymer for BSA in the IAGT an attractive option.
Asunto(s)
Tipificación y Pruebas Cruzadas Sanguíneas , Prueba de Coombs , Isoanticuerpos/análisis , Polietilenglicoles , Afinidad de Anticuerpos , Tipificación y Pruebas Cruzadas Sanguíneas/métodos , Humanos , Indicadores y Reactivos , Albúmina Sérica BovinaRESUMEN
A modification of the microaggregate filtration technique for the production of leukocyte-poor red cell concentrate is described. The modified technique, termed 'spin, cool, and filter', removed leukocytes more efficiently from relatively fresh blood than the original microaggregate filtration procedure. The residual leukocyte content of 4- to 9-day-old units processed by the modified procedure averaged less than 0.4 X 10(9) white cells per unit. The microaggregate filtration technique, supplemented by buffy-coat exclusion, removed more than 93 percent of the units' white cells. These red cell products were prepared easily and did not elicit febrile reactions in highly susceptible patients.
Asunto(s)
Conservación de la Sangre , Transfusión Sanguínea/economía , Separación Celular/métodos , Análisis Costo-Beneficio , Filtración , Humanos , Recuento de LeucocitosRESUMEN
An evaluation of the Haemonetics 102, an automated cell washing system, is presented. Although the system removes 68.4 +/- 14 per cent of the white blood cells from liquid stored blood, the percentage wash out is an unreliable mode of evaluation. The residual number of white blood cells per unit is 6.5 +/- 2.8 x 10(8), which is independent of the unit's size, age, and initial leukocyte count. The residual number of white blood cells is also not influenced by any of the modifications used in the study. Red blood cell loss averaged 16.3 per cent. A direct correlation exists between the initial red blood cell mass and the amount of cell lost. It is recommended that packed cell units which have a volume of less than 300 ml with hematocrits of 75 per cent or less be used to minimize excessive red blood cell loss. Recommendation as to the selection of units by an ideal age or the preparation of units prior to washing are not supported by these data.
Asunto(s)
Conservación de la Sangre , Eritrocitos , Técnicas Inmunológicas , Leucocitos , Separación Celular , Recuento de Eritrocitos , Humanos , Recuento de Leucocitos , Factores de TiempoRESUMEN
THsi study was designed to define the effect of positive end expiratory pressure (PEEP) ventilation on intracranial pressure (ICP). In 25 patients with severe head trauma with and without associated pulmonary injury the following parameters were simultaneously monitored under mechanical ventilation with and without PEEP:ICP, arterial blood pressure, central venous pressure, arterial blood gases, and cardiac rate. In addition, the volume-pressure response (VPR) was evaluted in each patient to assess cerebral elastance. The results indicate a significant increase in ICP with the application of PEEP only in the 12 patients who manifested increased cerebral elastance by VPR. Half of this latter group manifested impairment of cerebral perfusion pressure to levels less than 60 mm Hg. Return to baseline CIP levels was observed with termination of PEEP. No significantly consistent changes in other parameters were noted.