Search results for "Biological system"

Design and experimental validation of a generic model for combinatorial assembly of DNA tiles into 1D-structures.

2010

Abstract Background Quantitative modeling of the self-assembly of DNA tiles leading either to defined end-products or distribution of biopolymers is of practical importance for biotechnology and synthetic biology. Methods The combinatorial process describing tile assembly was implemented into a generic algorithm allowing quantitative description of the population of significant species accumulating during the reaction course. Experimental formation and characterization by optical and electrophoresis approaches of copolymers resulting from the self-assembly of a limited number of half-complementary tiles were used to define and validate generic rules allowing definition of model parameters. …

Comparative parallel characterization of particle populations with two mass spectrometric systems LAMPAS 2 and SPASS

2006

Abstract Two transportable laser mass spectrometers, Single Particle Analysis and Sizing System (SPASS) and Laser Mass Analyzer for Particles in the Airborne State (LAMPAS 2), have been applied to investigate the dependence of spectra patterns on instrumental parameters and data evaluation procedures in an inter-comparison experiment. Laboratory experiments showed the spectral response of both instruments for mineral particles before and after heterogeneous reactions. During a period of 47 h, both instruments determined size and chemical composition of several thousand single particles of an ambient particle population. Time-resolved evaluation (1-h resolution) of specific ion signals, whic…

EMERGING PROPERTIES IN POPULATION DYNAMICS WITH DIFFERENT TIME SCALES

1995

The aim of this work is to show that at the population level, emerging properties may occur as a result of the coupling between the fast micro-dynamics and the slow macrodynamics. We studied a prey-predator system with different time scales in a heterogeneous environment. A fast time scale is associated to the migration process on spatial patches and a slow time scale is associated to the growth and the interactions between the species. Preys go on the spatial patches on which some resources are located and can be caught by the predators on them. The efficiency of the predators to catch preys is patch-dependent. Preys can be more easily caught on some spatial patches than others. Perturbat…

Micromanipulation Techniques for the Isolation of Single Microorganisms

2005

A prerequisite for the biochemical and physiological investigation of microorganisms is the isolation and management of pure cultures. The only absolute criterion of purity for a bacterial culture is that it has been derived from the progeny of a single cell. Failure to apply this criterion may lead to much effort in proving the purity of a culture. All strains upon which research is to be based should therefore be rigorously purified before starting to investigate the properties of individual organisms (Johnstone 1969). Ecologically oriented microbiologists are faced especially with the problem of how to obtain a pure culture of certain microbial strains from their densely populated natura…

The interplay between cooperativity and diversity in model threshold ensembles

2014

The interplay between cooperativity and diversity is crucial for biological ensembles because single molecule experiments show a significant degree of heterogeneity and also for artificial nanostructures because of the high individual variability characteristic of nanoscale units. We study the cross-effects between cooperativity and diversity in model threshold ensembles composed of individually different units that show a cooperative behaviour. The units are modelled as statistical distributions of parameters (the individual threshold potentials here) characterized by central and width distribution values. The simulations show that the interplay between cooperativity and diversity results …

Characterization of microscopic disorder in reconstructed porous materials and assessment of mass transport-relevant structural descriptors

2016

The targeted optimization of the functional properties of porous materials includes the understanding of their transport properties and thus requires knowledge about the relationship between material synthesis, resulting in three-dimensional material morphology, and relevant transport properties. In this Perspective, we present our views and results on the characterization of microscopic disorder in functional porous materials, which are widely used today as fixed beds in adsorption, separation, and catalysis. This allows us to identify structural parameters that impact their mass transport properties and eventually their overall performance in technological operations. We address this comp…

Melanin type and concentration determination using inverse model

2011

Abnormality of melanin production causes skin pigmentation disorders. Currently, assessment of treatment efficacy (under Physician's Global Assessment framework) only refers to visual conditions of skin surface and not the condition of the underlying skin layers and pigments. Albeit researches on models and simulations of light interaction with human skin have been reported, none has been specifically developed for pigmentation analysis of melanin types - eumelanin and pheomelanin. Therefore, our research objectives are to develop image analysis of skin pigmentation for classification and quantification of eumelanin and pheomelanin pigment types in human skin. In this research, the model is…

Chaos and its Degradation-Promoting-Based Control in an Antithetic Integral Feedback Circuit

2022

This letter deals with a novel variant of antithetic integral feedback controller (AIFC) motifs which can feature robust perfect adaptation, a pervasive (desired) ability in natural (synthetic) biomolecular circuits, when coupled with a wide class of process networks to be regulated. Using the separation of timescales in the proposed kind of AIFC, here we find a reducedorder controller that captures the governing slow part of the original solutions under suitable assumptions. Inspired by R(ossler systems, we then make use of such a simpler controller to show that the antithetic circuit can exhibit chaotic behaviors with strange attractors, where the bifurcation from a homeostatic state to c…

BrdU is not a reliable label for transplanted cells in the central nervous system

2006

Performance Analysis of Single Cell Alkaline Electrolyser Using Mathematical Model

2019

Abstract The generation of hydrogen using electrolysis process with integrated renewable energy sources is very important specially in environmental aspects. In this paper, we demonstrate that, the performance of electrolysis process which could be enhanced by decreasing the distance between electrodes while changing the properties of electrodes. At first, two single cell alkaline electrolysers are fabricated using an in-house 3D printer. Thereafter, the best performing cell is selected by considering its performance through different experiments. Finally, the performance of the selected cell is analysed by changing the distance between electrodes and changing the properties of electrodes. …