Different resistance of mammalian red blood cells to hemolysis by bile salts

To evaluate why hemolysis of red blood cells (RBC) by bile acids varies in different mammalian species, we determined the mean corpuscular volume (MCV), lipid content and the concentrations of the conjugates of deoxycholate and of NaCl inducing 50% hemolysis of RBC from healthy humans, pigs, horses, cows, sheep and jaundiced humans. A volume of 0.05 mL of washed RBC at 1% hematocrit, which has the same lipid content but different phospholipid composition and number of erythrocytes (owing to the variable MCV), was incubated in taurodeoxycholate (TDC) solution (0–5 mM) to determine the TDC concentration inducing 50% hemolysis (TDC₅₀). The TDC₅₀ was highest in RBC of sheep and decreased within the series sheep>pig>cow>horse>healthy human>jaundiced human, which have generally increasing MCV. The osmotic resistance followed an inverse order, with jaundiced human >healthy human>horse>cow>pig>sheep. Although we found no correlation between the TDC₅₀ and phospholipid composition of the erythrocytes tested, the extent of bile salt-induced hemolysis seemed to depend on both the MCV and the number of erythrocytes in the incubation medium.     

Analysis of battery backup and switching controller for a fuel-cell powered automobile

In this paper, we consider the design of a fuel-cell powered automobile that utilizes methane as a source of hydrogen to power a PEM fuel cell. It is shown that when the power demand of the motor goes up suddenly, there is a time lag for generating the necessary hydrogen. A battery backup that provides the necessary power during this time lag is analyzed via an equivalent circuit model. A logic-based switching controller that switches between the fuel cell and the backup battery is designed to meet the power demand. The efficacy of this scheme is tested via simulations on a power profile obtained from a realistic speed profile of a small automobile.     

A stochastic model of catalytic reaction networks in protocells

Protocells are supposed to have played a key role in the self-organizing processes leading to the emergence of life. Existing models either (i) describe protocell architecture and dynamics, given the existence of sets of collectively self-replicating molecules for granted, or (ii) describe the emergence of the aforementioned sets from an ensemble of random molecules in a simple experimental setting (e.g. a closed system or a steady-state flow reactor) that does not properly describe a protocell. In this paper we present a model that goes beyond these limitations by describing the dynamics of sets of replicating molecules within a lipid vesicle. We adopt the simplest possible protocell architecture, by considering a semi-permeable membrane that selects the molecular types that are allowed to enter or exit the protocell and by assuming that the reactions take place in the aqueous phase in the internal compartment. As a first approximation, we ignore the protocell growth and division dynamics. The behavior of catalytic reaction networks is then simulated by means of a stochastic model that accounts for the creation and the extinction of species and reactions. While this is not yet an exhaustive protocell model, it already provides clues regarding some processes that are relevant for understanding the conditions that can enable a population of protocells to undergo evolution and selection.     

Adaptive controller for tracking power profile in a fuel cell powered automobile

In this paper, a model reference adaptive controller is designed using the Lyapunov method, for tracking a time varying power profile in an automobile powered by a fuel cell. The adaptability of the controller is tested by implementing the controller on different power profiles which simulate actual power requirement of different road conditions. The performance of the adaptive controller is compared with a conventional PID controller and it is observed that the adaptive controller has superior performance.     

Combined Management of Groundwater Resources and Water Supply Systems at Basin Scale Under Climate Change

Water stress conditions associated with population growth, climate change, and groundwater contamination, represent a significant challenge for all stakeholders in the water sector. Increasing the resilience of Water Supply Systems (WSSs) becomes of fundamental importance: along with an adequate level of service, sustainability targets must be ensured. A long-term management strategy is strictly connected to a holistic approach, based on analyses at different scales. To this end, both groundwater modeling tools and water management models, with different spatial and temporal scales, are routinely and independently employed. Here, we propose a coupled approach combining: i) groundwater models (MODFLOW) to investigate different stress scenarios, involving climate change and anthropic activities; ii) water management models (Aquator), to assess the water resources availability and the best long-term management strategy for large-scale WSS. The management models are implemented starting from input and output flows derived by groundwater models: this leads to establish a comprehensive framework usually not defined in management models and including a quantitative characterization of the aquifer. The proposed methodology, general and applicable to any study area, is here implemented to the WSS of Reggio Emilia Province, and its main groundwater resource, the Enza aquifer, considering three different stress scenarios for groundwater models (BAU, ST1, and ST2), and for management strategies (BAU, BAU_RV2, ST2). Among the key results, we observe that coupling the two model types: i) allows evaluating water resources availability in connection with management rules; ii) leads to examining more realistic operation choices; iii) permits planning of infrastructures at basin scale.

     

Modified paramagnetic beads in a microfluidic system for the determination of zearalenone in feedstuffs samples

In this work, we have developed and characterised a novel microfluidic immunoassay methodology for rapid and sensitive quantification of ZEA in feedstuffs samples. The detection of ZEA was carried out using a competitive direct immunoassay method based on the use of anti-ZEA monoclonal antibodies immobilized on magnetic microspheres 3-aminopropyl-modified manipulated for an external remobilize magnets. The ZEA in feedstuffs sample is allowed to compete with ZEA-horseradish peroxidase (HPR) conjugated for the immobilized anti-ZEA antibody. The HPR, in the presence of hydrogen peroxide (H₂O₂) catalyses the oxidation of 4-tert-butylcatechol (4-TBC) whose back electrochemical reduction was detected on gold electrode at 0.0 V. The calculated detection limits for electrochemical detection and ELISA procedure were 0.41 and 2.56 μg kg⁻¹ respectively, the intra and inter-assay coefficients of variation were below 6.5% and the total assay time was 30 min. The microfluidic immunosensor showed higher sensitivity and lower detection limits than the standard ELISA method, which shows potential for detecting ZEA in foods and feeds diagnosis.