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Biomedical subjects

M Ros

Publications and source records attributed to M Ros.

59 records · Page 4Linked to original sources
PubMed1983

Presence of cytosolic phosphoenolpyruvate carboxykinase activity in rat mammary gland.

The cytosolic P-enolpyruvate carboxykinase activity was measured in mammary gland and liver of animals at all stages of the reproductive cycle. The specific activity of this enzyme was almost absent in the mammary gland of virgin rats. Different pattern of P-enolpyruvate carboxykinase activity was obtained in liver and mammary gland during lactation cycle. The specific activity of the enzyme increased more than 40-fold in mammary gland and 2-fold in liver during the transition from mid-pregnancy to mid-lactation. Weaning of mid-lactating rats for 48 h resulted in an abrupt change in the enzyme activity in mammary gland while there was a small change in liver. In all the experiments performed, the activity of P-enolpyruvate correlates inversely with the plasma insulin levels described for the lactogenic process.

Animals↗
PubMed1982

The fluorescence of bilirubin upon interaction with human erythrocyte ghosts.

Bilirubin fluorescence increased upon interaction with bovine serum albumin and human erythrocyte ghosts. When bound to albumin, the emission maximum occurred at 534 +/- 3 nm with maximum excitation at 462 +/- 3 nm. Upon interaction with human erythrocyte ghosts, bilirubin fluorescence increased in a biphasic manner. A rapid initial increase was followed by a slower process that required at least 40 min to reach maximum enhancement at 25 degrees C. At equilibrium, bilirubin fluorescence in erythrocyte ghosts was heterogeneous. With 470 nm excitation, maximum emission occurred in the range of 520 to 535 nm. However, decreasing the excitation to 450 nm or below, produced a red shift in the emission difference spectra. These results suggest that bilirubin exists in different states or sites when associated with plasma membranes.

Bilirubin↗
PubMedDate not supplied

Design of a sequencing batch reactor sequence with an input load partition in a simulation-based experimental environment.

A study is presented that considers optimization of a sequencing batch reactor (SBR) operational sequence. Optimization is performed with the aid of a laboratory pilot plant and a process model. The model was included in the study to facilitate a search for optimal operating conditions because performing experiments solely on the pilot plant would be rather extensive, expensive, and time-consuming. The model used in the study is the well-known Activated Sludge Model No.1 with minor modifications. The optimization addresses a split-feed operating mode with input load partitioned into two parts and with two successions of aerobic-anoxic phases. In the study, the duration of batch phases and the time of the second input addition are optimized so that the desired effluent nitrogen concentration is achieved and the need for external carbon addition in the anoxic phase is reduced or eliminated. When an optimal SBR sequence computed by the model was verified on the pilot plant, better performance of the actual process was also achieved, although some phenomena were observed that were not predicted by the model. Results of the study indicate that the available wastewater treatment plant models, although a simplification of reality, can be usefully applied for process optimization.

Equipment Design↗
PubMedDate not supplied

Pre-fermentation of a low-strength meat-processing wastewater in an upflow sludge blanket reactor.

Pre-fermentation of low-strength wastewater from a meat processing facility (at 20 degrees C) was studied. A laboratory-scale upflow sludge blanket (USB) reactor was used for the experiments; 10 different operating conditions were tested with regard to the hydraulic residence time (HRT). At HRTs from 0.4 to 2.4 hours, the USB reactor produced effluent with acetate chemical oxygen demand from 82 to 100 mg/L. At HRTs shorter than 0.4 hours and upflow velocities greater than 0.5 m/h, biomass washout was observed. At HRTs longer than 2.4 hours, acetate concentration in the effluent and acetate production efficiency decreased. The transformation of organic nitrogen to ammonia-nitrogen occurred simultaneously with acetate production. Minimal accumulation of biomass in the USB reactor was observed. Pre-fermentation of the low-strength industrial wastewater in the USB reactor could be beneficial for biological nitrogen removal. The produced acetate is directly available for denitrification and the transformed ammonia-nitrogen is directly available for nitrification in the subsequent wastewater treatment steps.

Bioreactors↗