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Biomedical subjects

A Elías

Publications and source records attributed to A Elías.

8 recordsLinked to original sources
PubMed2006

Neural networks as a tool for control and management of a biological reactor for treating hydrogen sulphide.

Based on an experimental database consisting of 194 daily cases, artificial neural networks were used to model the removal efficiency of a biofilter for treating hydrogen sulphide (H2S). In this work, the removal efficiency of the reactor was considered as a function of the changes in the air flow and concentration of H2S entering the biofilter. In order to obtain true representative values, the removal efficiencies (outputs) were measured 24 h after each input was changed. A MLP (multilayer perceptron 2-2-1) model with two input variables (unit flow and concentration of the contaminant fed into the biofilter) rendered good prediction values with a determination coefficient of 0.92 for the removal efficiency within the range studied. This means that the MLP model can explain 92% of the overall variability detected in the biofilter corresponding to a wide range of operating conditions.

Air Pollutants↗
PubMed2001

Metal associations in soils before and after EDTA extractive decontamination: implications for the effectiveness of further clean-up procedures.

The distribution of Pb, Ni and Zn in two contaminated soils was determined before and after treating the soils with an EDTA solution. After the EDTA extraction, the proportion of Pb accumulated in the acid-extractable fraction considerably increased, which was related to the greater degree of metal extraction from the other fractions. EDTA was also able to extract certain amounts of Pb, Zn and Ni from the silicate matrix, which implied that these extractable amounts were not so strongly fixed to the residual fraction as previously supposed. As a consequence, after EDTA application, metal content (especially Pb) remained more weakly adsorbed to soil components (more easily leachable), potentially favouring the application of phytoremediation technologies. The extraction recoveries (for only one application) were generally low for the three metals (33-37% for Pb, 5-11% for Ni and 14-19% for Zn), although this fact is an advantage as plants would not be able to assimilate very high mobilised contents of metals.

Chelating Agents↗
PubMed2001

Allelopathic agents from Cyrtocymura cincta.

The sesquiterpenoid fractions from the chloroform extracts of roots and aerial parts of the weed Cyrtocymura cincta (Griseb.) H. Robinson (Compositae) were tested to observe the effects on seed germination and growth of three dicot and four monocot species. Promotion and inhibition effects were observed according to the examined compound, specific seed or cultivar, and concentration.

Argentina↗
PubMed2000

Application of biofiltration to the degradation of hydrogen sulfide in gas effluents.

A laboratory scale bioreactor has been designed and set up in order to degrade hydrogen sulfide from an air stream. The reactor is a vertical column of 7 litre capacity and 1 meter in height. It is divided into three modules and each module is filled with pellets of agricultural residues as packing bed material. The gas stream fed into the reactor through the upper inlet consists of a mixture of hydrogen sulfide and humidified air. The hydrogen sulfide content in the inlet gas stream was increased in stages until the degradation efficiency was below 90%. The parameters to be controlled in order to reach continuous and stable operation were temperature, moisture content and the percentage of the compound to be degraded at the inlet and outlet gas streams (removal or elimination efficiency). When the H2S mass loading rate was between 10 and 40 g m(-3) h(-1), the removal efficiency was greater than 90%. The support material had a good physical performance throughout operation time, which is evidence that this material is suitable for biofiltration purposes.

Biodegradation, Environmental↗
PubMed1979

[Macrocytosis in chronic alcoholism (author's transl)].

The present study reported a group of 168 chronically alcoholic patients with a daily ingestion superior to 80 grams. Twenty of these patients (10 percent) did not have liver disease, and 148 (68.5 percent) had different forms of liver disease classified by histopathologic examination. Considering a 97 fi MCV as macrocytosis, we have found in the group of alcoholics without hepatopathy a 50 percent rate of macrocythemia with a mean value of 97.9 fl. In the group of chronic alcoholics with liver disease there was a 64.2 percent macrocytosis with a mean value of 100 fl. We have also studied 43 (21.5 percent) patients with cryptogenetic cirrhosis with a 32.6 percent macrocytosis and a mean value of 93.9 fl. With respect to the alcoholic hepatopathy subgroups, macrocytosis is more frequent in portal fibrosis and acute alcoholic hepatitis, the mean value being higher in the latter. We consider macrocytosis to be frequent among alcoholics, and a good persistence indicator of alcoholic ingestion, pathogenically linked to the now proven dyserythropoietic factor of the alcohol upon the bone marrow. There is no statistically significant correlation between anemia and reticulocytes. We consider macrocytosis to be a more precocious data, and believe that the positive correlation with certain intraerythrocitary enzymes in the juvenile population of red cells corroborates this fact. With respect to the rest of parameters studied there was a correlation with gammaglutamiltranspeptidase, glutamic-oxalacetic transaminase, and the value of prothrombin. The values of mean macrocytosis and elevations of gammaglutamiltranspeptidase and glutamic-oxalacetic transaminase are good persistence indicators of alcoholic ingestion.

Alcoholism↗