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Genes for the GABA(A) receptor subunit types and their expression
No full textNo abstract available
A novel simulation model for stem cells differentiation
No full textA novel mathematical model to simulate mesenchymal stem cells differentiation into specialized cells is proposed. The model is based upon material balances for extracellular matrix compounds, growth factors and nutrients coupled with a mass-structured population balance describing cell growth, proliferation and differentiation. The proposed model is written in a general form and it may be used to simulate a generic cell differentiation pathway occurring in vivo or during in vitro cultivation when specific growth factors are used. Literature experimental data concerning the differentiation of mesenchymal stem cells into chondrocytes in terms of total DNA and glycosaminoglycan content are successfully compared with model results, thus demonstrating the validity of the proposed model as well as its predictive capability. A further test of the model capability is performed for the case of in vivo fracture healing during which mesenchymal stem cells differentiate into chondrocytes and osteoblasts. Considerations about the extension of the proposed model to different pathologies beside fracture healing are reported. Finally, sensitivity analysis of model parameters is also performed in order to clarify what mechanisms most strongly influence differentiation and the distribution of cell types. © 2007 Elsevier B.V. All rights reserved
A novel mathematical model to simulate the size-structured growth of microalgae strains dividing by multiple fission
No full textSeveral microalgae strains are capable to divide by multiple fission, namely they can give rise to variable number of daughter cells after cytokinesis. Such behavior may have implications on the overall growth and productivities of microalgal cultures that are difficult to infer intuitively. Consequently, a novel mathematical model to simulate the dynamics of the size-structured growth of microalgal strains characterized by multiple fission, is proposed in this work. The model relies on the use of population balance equations (PBEs) to describe the evolution of the size distribution of microalgae cells during growth and permits to decouple the single cell growth phase, which is known to take place in the light, from the division one, that on the contrary is assumed to occur under dark conditions according to well corroborated experimental observations. Moreover, the effect of light intensity, photoperiod and nutrients concentration on the continuous growth of the cells, are suitably accounted for by the model. Furthermore, in order to describe the partition of newborn cells after division, a new approach, which relies on suitable experimental observations, is developed to formulate a novel birth term related to PBEs which takes into account the possibility of multiple fission to take place. Model results and literature experimental data pertaining a strain capable to divide by multiple fission, are successfully compared in terms of biomass concentration evolution, thus highlighting a good predictive capability of the model. Subsequently, specific numerical experiments are performed in order to examine the potential improvements arising from this model with respect to the ones currently available in the literature. Finally, suitable simulation based inferences are formulated about the potential implications of multiple fission on photobioreactor's productivity. (C) 2015 Elsevier B.V. All rights reserved
Mechanochemical immobilization of heavy metals in contaminated soils: A novel mathematical modeling of experimental outcomes
No full textMechanochemical processing to immobilize heavy metals in contaminated soils has been proposed few years ago. The corresponding experimental results have shown that, under specific operating conditions, the mechanical energy provided by suitable ball mills, can greatly reduce heavy metals mobility without the addition of any reactant. Such results, together with the extreme simplicity of the proposed technique, are still very promising in view of its industrial transposition. Along these lines, the use of suitable mathematical models might represent a valuable tool which would permit to design and control mechano-chemical reactors for field applications. In this work, a simple albeit exhaustive model is proposed for the first time to quantitatively describe the effects of the dynamics of milling process, such as impact frequency and energy, on the immobilization kinetics. Model results and experimental data obtained so far are successfully compared in terms of leached heavy metals and immobilization efficiency evolution with treatment time. Finally, the potential capability of the model to contribute to the industrial scale transposition of the proposed technique is addressed
Mathematical modelling of chlorella vulgaris growth in semi-batch photobioreactors fed with pure CO2
No full textThe brain as a target of hormonal contraceptives: Evidence from animal studies
No full textHormonal contraceptives are frequently prescribed drugs among women, mainly for their reversible contraceptive purposes but also for beneficial effects in some gynecological pathologies. Despite extensive studies aimed at elucidating the physical effects of hormonal contraceptives and ameliorating some unwanted outcomes, little is known yet about the effects of these drugs on brain function and related behavior, which are known to be modulated by endogenous steroid hormones. We describe the current literature on preclinical studies in animals undertaken to investigate effects of hormonal contraceptives on brain function and behavior. These studies suggest that hormonal contraceptives influence neurohormones, neurotransmitters, neuropeptides, and emotional, cognitive, social and sexual behaviors. Animals allow examination of the basic biological mechanisms of these drugs, devoid of the psychological aspect often associated to hormonal contraceptives' use in women. Understanding the neurobiological effects of these drugs may improve women's health and may help women making informed choices on hormonal contraception
Novel simulation model of the solar collector of BIOCOIL photobioreactors for CO2 sequestration with microalgae
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