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Abstract: In this paper, the numerical treatment for two nonlinear advance delay differential system is discussed. This system arises during the study of conduction of impulses down myelinated axons, incorporating electrical properties of the myelin. This system consists of two coupled first-order equations, one having a delay term and the other having an advance one. The modified difference scheme is used and then applied to some test problems. [Copyright &y& Elsevier]

In this work, a nanostructured conductive film possessing nanozyme features was straightforwardly produced via laser-assembling and integrated into complete nitrocellulose sensors; the cellulosic substrate allows to host live cells, while the nanostructured film nanozyme activity ensures the enzyme-free real-time detection of hydrogen peroxide (H 2 O 2) released by the sames. In detail, a highly exfoliated reduced graphene oxide 3D film decorated with naked platinum nanocubes was produced using a CO 2 -laser plotter via the simultaneous reduction and patterning of graphene oxide and platinum cations; the nanostructured film was integrated into a nitrocellulose substrate and the complete sensor was manufactured using an affordable semi-automatic printing approach. The linear range for the direct H 2 O 2 determination was 0.5–80 μM (R2 = 0.9943), with a limit of detection of 0.2 μM. Live cell measurements were achieved by placing the sensor in the culture medium, ensuring their adhesion on the sensors' surface; two cell lines were used as non-tumorigenic (Vero cells) and tumorigenic (SKBR3 cells) models, respectively. Real-time detection of H 2 O 2 released by cells upon stimulation with phorbol ester was carried out; the nitrocellulose sensor returned on-site and real-time quantitative information on the H 2 O 2 released proving useful sensitivity and selectivity, allowing to distinguish tumorigenic cells. The proposed strategy allows low-cost in-series semi-automatic production of paper-based point-of-care devices using simple benchtop instrumentation, paving the way for the easy and affordable monitoring of the cytopathology state of cancer cells. [ABSTRACT FROM AUTHOR]

Quantum-dot cellular automata (QCA) nanotechnology is one of the proposed technologies for replacing CMOS technology. Shift registers are one of the important areas in the design of digital circuits and memory structures. Given the importance of shift registers, in this paper, new structures have been proposed for shift registers in QCA nanotechnology. At first, proposed D-latch is presented to be used in the main block of shift registers, which has only 18 cells, a delay of 0.5 cycles and less area than previous designs. Subsequently, a 4-bit series register will be presented using the proposed D-latch, which is at least 30% lower than the previous ones in terms of cell numbers and area. In addition, a reset pin is needed in shift registers which are used in microprocessors. Most of the previous designs did not have the reset pins and therefore a new version of 4-bit shift register which has the reset pin will be presented in this paper. New and former designs have been expanded from 2 bits to 8 bits, and parameters variations are presented in the table and diagrams. The proposed new designs have interesting features in terms of stability, number of cells and occupied area, compared to previous designs that do not have the reset capability. In addition, the proposed shift register is used to design an optimized LFSR circuit in QCA nanotechnology with only 157 cells and 0.2 µm2 area. [ABSTRACT FROM AUTHOR]

When yeast cells enter into quiescence in response to nutrient limitation, the adenine deaminase Aah1p is specifically degraded via a process requiring the F-box protein Saf1p and components of the Skp1-Cullin-F-box complex. In this paper, we show that Saf1p interacts with both Aah1p and Skp1p. Interaction with Skp1p, but not with Aah1p, requires the F-box domain of Saf1p. Based on deletion and point mutations, we further demonstrate that the F-box domain of Saf1p is critical for degradation of Aah1p. We also establish that overexpression of Saf1p in proliferating cells is sufficient to trigger the degradation of Aah1p. Using this property and a two-dimensional protein gel approach, we found that Saf1p has a small number of direct targets. Finally, we isolated and characterized several point mutations in Aah1p, which increase its stability during quiescence. The majority of the mutated residues are located in two distinct exposed regions in the Aah1p three-dimensional model structure. Two hybrid experiments strongly suggest that these domains are directly involved in interaction with Saf1p. Importantly, we obtained a mutation in Aah1p that does not affect the protein interaction with Saf1p but abolishes Aah1p degradation. Because this mutated residue is an exposed lysine in the Aah1p three-dimensional model, we propose that it is likely to be a major ubiquitylation site. All together, our data strongly argue for Saf1p being a bona fide Skp1-Cullin-F-box subunit. [ABSTRACT FROM AUTHOR]

Takotsubo syndrome (TTS) has been a recognized clinical entity for 31 years, since its first description in 1990. TTS is now routinely diagnosed in patients who present with acute chest pain, electrocardiographic changes, troponin elevation, unobstructed coronary arteries, and a typical pattern of circumferential left ventricular wall motion abnormalities that usually involve the apical and midventricular myocardium. Increasing understanding of this intriguing syndrome stems from wider recognition, possible increasing frequency, and a rising number of publications focused on the pathophysiology in clinical and laboratory studies. A comprehensive understanding of TTS pathophysiology and evidence-based treatments are lacking, and specific and effective treatments are urgently required. This paper reviews the pathophysiology of this fascinating syndrome; what is known from both clinical and preclinical studies, including review of the evidence for microvascular dysfunction, myocardial beta-adrenergic signaling, inflammation, and electrophysiology; and where focused research needs to fill gaps in understanding TTS. [ABSTRACT FROM AUTHOR]

Target cells contagion has sparked the necessity of a multiple target cell model with chronic infection and intracellular delay (MTC-CI-ID). This paper seeks to advance a viral dynamical model with multiple target cells and corroborate the global stability of their steady states. Hence, the affiliation of the virus with two classes of target cells, CD4 + Tcells and macrophage. The time delay amidst viral entry and the output of virions were intimated and the basic reproductive number was procured, as the long term behavior of the model and less than unity. The contagious free equilibrium E 0 was unveiled as locally and globally asymptotically stable. The conditions of an infected CD4 + Tcell and macrophage on viral production were engaged. It was ascertained that CD4 + Tcell accounts for larger amounts of virions in the blood as per macrophage cells. Hence, varying time delay has no impact on peak viral levels, but only shelves the viral peaking time. The adopted model has unrestrained bearing on HIV-1 therapy. [ABSTRACT FROM AUTHOR]

Given an arbitrary set T in the Euclidean space R n , whose elements are called sites, and a particular site s , the farthest Voronoi cell of s , denoted by F T (s) , consists of all points which are farther from s than from any other site. In this paper we study farthest Voronoi cells and diagrams corresponding to arbitrary (possibly infinite) sets. More in particular, we characterize, for a given arbitrary set T , those s ∈ T such that F T (s) is nonempty and study the geometrical properties of F T (s) in that case. We also characterize those sets T whose farthest Voronoi diagrams are tesselations of the Euclidean space, and those sets that can be written as F T (s) for some T ⊂ R n and some s ∈ T. [ABSTRACT FROM AUTHOR]

• A complete theoretical analysis of a modified version of the Scalar Reference Gorvernor subjected to OR constraints. • An additional case study has been described to show the effectiveness of the proposed method in a variety of situations. • Experimental validation on a Li-ion graphite/LCO battery. In this paper, we propose a solution for the control of the state-of-charge of a lithium-ion (Li-ion) battery cell. The aim is to design a control scheme able to charge the battery in a fast way while ensuring that the safety constraints of the electrochemical model (ECheM) of the battery are not violated. The proposed solution is based on a novel computationally efficient formulation of the Reference Governor (RG) able to deal with the union of linear constraints and which has been designed on the basis of a reduced ECheM, namely the equivalent-hydraulic model (EHM). Using suitable safety margins, the satisfaction of the constraints on the EHM ensures the satisfaction of the constraints on the full-order ECheM. Simulation results obtained on an accurate simulator show that the proposed method, if compared with classical charge strategies, is able to considerably improve the charge performance while ensuring the satisfaction of the constraints. These findings are validated experimentally on a Li-ion graphite/LCO battery. [ABSTRACT FROM AUTHOR]

Polarimetric radars make it possible to retrieve information on hydrometeors types, sizes and concentrations. Additional information on cloud electrification can be obtained from Lightning Mapping Arrays (LMAs). To study the development time and height of the hydrometeors and electrification require tracking their evolution within the lifecycle of convective cells. A new methodology for multi-cell identification and tracking (MCIT) is presented in this study. The algorithm in this study is different from traditional tracking methods; this new algorithm is applied to time series of radar volume scans. It tracks local maxima of vertically integrated liquid (VIL) water by identifying the two cells in consecutive radar scans that have maximum common VIL. The vertical profile of the polarimetric variables is used for constructing the time-height cross section of the cells' microphysical properties around the peak reflectivity as a function of height. The LMA sources that occur within the cell area are integrated as a function of height as well for each time step, as determined by the radar volume scans. The result of the tracking can provide insights on the evolution of storms, hydrometer types, precipitation initiation and cloud electrification under different thermodynamic and aerosol conditions. The details of the MCIT algorithm, its products and their performance for different type of storms are described in this paper. • Development of a novel cloud cell tracking algorithm. • Tracking cloud types include: convective and stratiform, isolated and clustered. • Tracking cloud cells through maturation into stratiform storm elements. • Use a synergy of polarimetric radar, satellite, lightning detection and model data. • Algorithm has flexible output options and possibilities for further studies. [ABSTRACT FROM AUTHOR]

Accurate power prediction for a battery pack is of great importance for efficient and safe operation of electric vehicles. However, a battery pack typically consists of dozens of cells connected in series, and how to accurately predict its peak power in practical applications has always been a challenging issue. This paper proposes a low-complexity peak power prediction method for a series-connected battery pack, where the peak power of battery pack is predicted depending only on representative cells. Firstly, considering state of charge and voltage limits for power prediction, the representative cells are selected by using two easily available variables, namely characteristic voltage and ohmic resistance. Secondly, the state of charge and voltage of the representative cell are estimated accurately by the dual adaptive extended Kalman filter algorithm. Finally, the multi-parameter limited method for battery pack is developed to predict the peak power under Urban Dynamometer Driving Schedule test at different temperatures. The experimental results verify the feasibility and robustness of the proposed selection method, and the peak power of battery pack is predicted with low complexity and high accuracy. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents Large Eddy simulations of flow and acoustic computations around 2D and 3D airfoils using a novel type of mesh called voxel mesh. Voxel mesh refers to the mesh that has different number of nodes in the neighbouring cell layers. Voxel mesh has many advantages such as creating cells with minimum skewness, automatic mesh generation and uniformity in cell shapes and sizes. The voxel meshes aren’t yet validated in boundary layer computations. In this paper we validate the use of voxel meshes in boundary layer computations in 2D and 3D airfoils. Six cases were tried out in the research three 2D meshes and three 3D cases were tried out. Each case was simulated at Reynolds number 2.83×105 and attack angle of 90. Flow field computation was done by FrontFlowBlue-7.2 software the acoustic computation was done by using FrontFlowBlue-Acoustic2.2 software. The results obtained from the simulations were compared with the experimental values. The use of voxel meshes to resolve the boundary layer in turbulent fluid flows could be validated using 2D airfoils. Therefore voxel meshes were used in 3D airfoil flow computations. After successful flow computations the source fluctuations in the flow was used for the acoustic computations. The sound pressure levels computed from the acoustic computations were compared with the experimental values. Some oscillation in the pressure could be observed due to the step like structure at the surface of voxel mesh but these variations were less apparent in meshes that had smaller cells. [Copyright &y& Elsevier]

Time-lapse microscopy has thoroughly transformed our understanding of biological motion and developmental dynamics from single cells to entire organisms. The increasing amount of cell tracking data demands the creation of tools to make extracted data searchable and interoperable between experiment and data types. In order to address that problem, the current paper reports on the progress in building the Cell Tracking Ontology (CTO): An ontology framework for describing, querying and integrating data from complementary experimental techniques in the domain of cell tracking experiments. CTO is based on a basic knowledge structure: the cellular genealogy serving as a backbone model to integrate specific biological ontologies into tracking data. As a first step we integrate the Phenotype and Trait Ontology (PATO) as one of the most relevant ontologies to annotate cell tracking experiments. The CTO requires both the integration of data on various levels of generality as well as the proper structuring of collected information. Therefore, in order to provide a sound foundation of the ontology, we have built on the rich body of work on top-level ontologies and established three generic ontology design patterns addressing three modeling challenges for properly representing cellular genealogies, i.e. representing entities existing in time, undergoing changes over time and their organization into more complex structures such as situations. [ABSTRACT FROM AUTHOR]

• Drones(UAVs) can provide wireless coverage when infrastructure is down (disaster-hit areas). • Delaunay Triangulation based initial deployment offers maximum continuous coverage area. • Mobility of users causes some hotspot cells overloaded (Hot Zones). • Load sharing among UAVs dynamically can help mitigate overload at a hotspot cell. • Later, judicious selection of UAVs to move them closer to overloaded UAVs helps serving users better. Unmanned Aerial Vehicle (UAV) networks can provide wireless coverage to users when cellular infrastructure is unavailable. Each UAV covers a circular area, called a hotspot cell , and serves the users in it. Natural disasters can cause unpredictable mobility of users, randomly overloading some cells, called hot zones , for different time intervals. Along with an efficient initial deployment, this paper presents a two-fold approach to handle hot zones. First, the loads in overlapped sections are redistributed to neighbors. Second, a distributed algorithm is run that dynamically repositions the least number of UAVs to serve the maximum possible users. Additionally, to balance the user demand and supply of wireless coverage, adjacent UAVs are allowed to swap their positions. Simulation results show improvement in the network performance using the parameters: packet delivery ratio, data served per unit of depleted energy, service discontinuity time, and the total amount of data served. [ABSTRACT FROM AUTHOR]

In this paper, we propose two independent gate (IG) FinFET SRAM cells that use PMOS access transistors and back-gate (BG) biasing to achieve a high-stability performance. In the first cell, the back-gate of the access transistors is connected to the adjacent storage nodes, and the back-gate of the pull-down transistors is dynamically biased. Simulations indicate that the first proposed cell offers higher read static noise-margin (SNM), higher write-ability, least static/dynamic power, and a comparable read current compared to the previous IG-6TSRAMs. The second cell is a novel independently-controlled-gate FinFET SRAM cell, which provides a high read stability, the highest write-ability, low static power dissipation and high read current compared to the previously reported independently-controlled-gate FinFET SchmitTrigger based SRAM cells. This cell supportsbit-interleaving property at V DD = 0.4 V with high read/write yields. [ABSTRACT FROM AUTHOR]

Abstract Processes occurring in the cellular and extracellular environment with the participation of elements both essential due to their vital functions and harmful to organism are complex and depend on many factors. The type of element and its chemical form as well as chemical composition of environment in which they occur play the significant role in the processes. But quantitative relationships between elements are also important, since both the excess and deficiency perturb their homeostasis in the organism. They can interact with each other at the absorption stage, transport in the blood, distribution in tissues and excretion. Quantitative correlations between Ca, Mg, Zn, Cu, Fe, Mn, Cr, Ni, Pb, Cd, and Al in some body fluids (serum, urine), cells (red blood cells) and tissues (human and animal hair, muscle and bone tissue, liver, kidney, stomach) are presented in the paper. It was stated that the following pairs of elements correlate most often: Ca-Mg, Mg-Zn, Cu-Zn, Fe-Cd, and Pb-Cd. It seems that the crucial role in the correlations between elements play their similarity in chemical and physical properties (first of all the size of ions radius and electric charge), the life processes in which the elements participate and the common environmental origin). Highlights • Interactions between elements in biological material have been studied. • Ca, Mg, Zn, Cu, Fe, Mn, Pb, Cd, Al, Cr, and Ni relationships were analyzed. • Correlations were described in body fluids, cells, human and animal tissues. • Pairs of elements: Ca-Mg, Mg-Zn, Cu-Zn, Fe-Cd, and Pb-Cd correlate most often. • Similar physicochemical properties are mainly responsible for elements interaction. [ABSTRACT FROM AUTHOR]

Highlights • A method for topology identification and form finding of planar tensegrity systems is proposed. • Tensegrity systems are composed of elementary units (cells) through a bio-inspired process. • Unit interaction is explained through the identification of stable sub-systems (virtual cells). • The method allows to control the final shape of the structure and its self-stress states. Abstract Tensegrity structures are frameworks in a stable self-equilibrated prestress state that have been applied in various fields in science and engineering. Research into tensegrity structures has resulted in reliable techniques for their form finding and analysis. However, most techniques address topology and form separately. This paper presents a bio-inspired approach for the combined topology identification and form finding of planar tensegrity structures. Tensegrity structures are generated using tensegrity cells (elementary stable self-stressed units that have been proven to compose any tensegrity structure) according to two multiplication mechanisms: cellular adhesion and fusion. Changes in the dimension of the self-stress space of the structure are found to depend on the number of adhesion and fusion steps conducted as well as on the interaction among the cells composing the system. A methodology for defining a basis of the self-stress space is also provided. Through the definition of the equilibrium shape, the number of nodes and members as well as the number of self-stress states, the cellular multiplication method can integrate design considerations, providing great flexibility and control over the tensegrity structure designed and opening the door to the development of a whole new realm of planar tensegrity systems with controllable characteristics. [ABSTRACT FROM AUTHOR]

Abstract: Live-cell imaging has become a powerful analytical tool in most cell biology laboratories. The scope of this paper is to give an overview of the environmental considerations for maintaining living cells on the microscope stage and the technical advances permitting multi-parameter imaging. The paper will then focus on two-dimensional and three-dimensional analysis of cell dispersion and migration and finally give a brief insight on computational modeling of the cell behavior. [Copyright &y& Elsevier]

Abstract: This paper considers a generalization of various communication models based on the P system paradigm where two objects synchronously move across components. More precisely, the model uses blocks of four cells such that pairs of objects from two input cells travel together to target output cells. It is shown that the model introduced, based on interactions between blocks, is complete, being able to generate all recursively enumerable sets of natural numbers. It is also proven that completeness is achievable by using a minimal interaction between blocks, i.e. every pair of cells is the input or output for at most one block. It is also shown that the concepts introduced in this paper to define the model may be simulated by more particular communication primitives, including symport, antiport and uniport rules. This enables us to automatically translate a system using interaction rules in any of minimal symport, minimal antiport or conditional uniport P systems. [Copyright &y& Elsevier]

This and a companion paper report a means to assess fungal prevalence in ambient air by measuring the ergosterol concentration. The results are highly reproducible. Twelve species and strains of fungal spores and yeast cells commonly found in ambient air in the subtropics were cultured in the laboratory. Gas chromatography–mass spectrometry (GC–MS) was used to determine their ergosterol content. (1) The specific ergosterol content of the 12 species ranged from 0.047 to 9.919pg(spore or yeast cell)−1. (2) It was found that the larger the surface area of the spore/yeast cell, the higher the specific ergosterol content. (3) The specific ergosterol content of the spores or cells increased during vegetative growth of the parent cells, but became steady once the parent had matured. (4) Ergosterol was found to decompose in autoclaved spores or yeast cells, but a substantial amount of the ergosterol remained. Therefore, ergosterol can be used to reflect both the viable and the non-viable fungal mass. In a companion paper, an empirical general conversion factor for determining fungal concentration from field ergosterol measurements is proposed. [Copyright &y& Elsevier]

Abstract: This paper presents a new approach to higher-level information fusion in which knowledge and data are represented using semantic networks composed of coupled spiking neuron nodes. Networks of simulated spiking neurons have been shown to exhibit synchronization, in which sub-assemblies of nodes become phase locked to one another. This phase locking reflects the tendency of biological neural systems to produce synchronized neural assemblies, which have been hypothesized to be involved in binding of low-level features in the perception of objects. The approach presented in this paper embeds spiking neurons in a semantic network, in which a synchronized sub-assembly of nodes represents a hypothesis about a situation. Likewise, multiple synchronized assemblies that are out-of-phase with one another represent multiple hypotheses. The initial network is hand-coded, but additional semantic relationships can be established by associative learning mechanisms. This approach is demonstrated by simulation of proof-of-concept scenarios involving the tracking of suspected criminal vehicles between meeting places in an urban environment. Our results indicate that synchronized sub-assemblies of spiking nodes can be used to represent multiple simultaneous events occurring in the environment and to effectively learn new relationships between semantic items in response to these events. In contrast to models of synchronized spiking networks that use physiologically realistic parameters in order to explain limits in human short-term memory (STM) capacity, our networks are not subject to the same limitations in representational capacity for multiple simultaneous events. Simulations demonstrate that the representational capacity of our networks can be very large, but as more simultaneous events are represented by synchronized sub-assemblies, the effective learning rate for establishing new relationships decreases. We propose that this effect could be countered by speeding up the spiking dynamics of the networks (a tactic of limited availability to biological systems). Such a speedup would allow the number of simultaneous events to increase without compromising the learning rate. [Copyright &y& Elsevier]

Abstract: The line of epithelial-like Chinese hamster ovary (CHO) cells was initiated by T.T. Puck in 1957. Since then, CHO cells have become a widely used mammalian expression system in industry and science. This paper discusses the different features of CHO cell physiology as well as the specific aspects of using these cells for ion channel studies; among the discussed features are the culturing and transfection of CHO cells, details of electrophysiological recordings from them and applications for the study of ion channel physiology and pharmacology. Examples of successful reconstitution of mammalian ion channels in CHO cells discussed in the paper include reconstitution of KCNQ channel regulation by muscarinic acetylcholine receptors and the study of the amiloride-sensitivity of epithelial sodium channels (ENaC). [Copyright &y& Elsevier]

The original papers of Hodgkin and Huxley (J. Physiol. 116 (1952a) 449, J. Physiol. 116 (1952b) 473, J. Physiol. 116 (1952c) 497, J. Physiol. 117 (1952d) 500) have provided a benchmark in our understanding of cellular excitability. Not surprisingly, their model of the membrane action potential (AP) requires revisions even for the squid giant axon, the preparation for which it was originally formulated. The mechanisms they proposed for the voltage-gated potassium and sodium ion currents, IK, and INa, respectively, have been superceded by more recent formulations that more accurately describe voltage-clamp measurements of these components. Moreover, the current–voltage relation for IK has a non-linear dependence upon driving force that is well described by the Goldman–Hodgkin–Katz (GHK) relation, rather than the linear dependence on driving force found by Hodgkin and Huxley. Furthermore, accumulation of potassium ions in the extracellular space adjacent to the axolemma appears to be significant even during a single AP. This paper describes the influence of these various modifications in their model on the mathematically reconstructed AP. The GHK and K+ accumulation results alter the shape of the AP, whereas the modifications in IK and INa gating have surprisingly little effect. Perhaps the most significant change in their model concerns the amplitude of INa, which they appear to have overestimated by a factor of two. This modification together with the GHK and the K+ accumulation results largely remove the discrepancies between membrane excitability of the squid giant axon and the Hodgkin and Huxley (J. Physiol. 117 (1952d) 500) model previously described (Clay, J. Neurophysiol. 80 (1998) 903). [Copyright &y& Elsevier]

The IUPS Physiome Project is an internationally collaborative open-source project to provide a public domain framework for computational physiology, including the development of modelling standards, computational tools and web-accessible databases of models of structure and function at all spatial scales. A number of papers in this volume deal with the development of specific mathematical models of physiological processes. This paper stands back from the detail of individual models and reviews the current state of the IUPS Physiome Project including organ and organ system continuum models, the interpretation of constitutive law parameters in terms of micro-structural models, and markup languages for standardizing cellular processes. Some current practical applications of the physiome models are given and some of the challenges for the next 5 years of the Physiome Project at the level of organs, cells and proteins are proposed. [Copyright &y& Elsevier]

In the paper published by Wu and Jiang (Int. J. Impact. Eng. 19(5/6) (1997) 439), the experimental results of quasi-static and impact tests on six types of honeycomb cellular structures have been compared with theoretical predictions. The values of some of the parameters used in the formulae in their paper, seem to be incorrect. In this paper the cause of inaccuracy and the correct values of these parameters have been presented. [Copyright &y& Elsevier]

This paper deals with a critical analysis of the kinetic cellular theory which refers to the modelling of the immune response to the evolution of the progression of endothelial cells which have lost their differentiation and start their evolution towards metastatic states. The first part of the paper deals with the development of a general framework including, as special cases, the various models proposed in the literature and, possibly, various generalizations. The second part deals with the analysis of some specific mathematical models. Finally, the third part deals with the indication of research perspectives. [Copyright &y& Elsevier]

• We propose a robust approach to segment and identify various types of cells robustly. • We utilize the Gabor filter enhanced gradients to segment the cell foreground. • We compare state of the art threshold selection methods quantitatively to select the optimal one. • We combine iterative erosion and area-constrained ultimate erosion to separate the connected cells. Research on cell segmentation is experiencing growing pains that need to be addressed for developing generic and robust techniques. The diversity of cells is growing rapidly and the demand for segmenting different types of cell images continue to increase in recent years. It is still very challenging for existing methods to segment various types of cells automatically and robustly. In this paper, we try to address this challenge by proposing an approach that is capable of segmenting various types of cells robustly. To avoid the effect of the global intensity variations, the gradients of cells are computed and then smoothed by the Gabor filter to generate the gradient image with increased intensity uniformity. To find the optimal method for cell foreground segmentation, we evaluated and compared state of the art threshold selection methods extensively. The slope difference distribution (SDD) method was testified as the optimal threshold selection method for cell segmentation and its optimal parameters were obtained in this paper based on a variety of cell images. We tested several morphological erosion methods and combined the iterative erosion method and the area-constrained ultimate erosion method to separate the connected cells robustly. Thirteen types of cells were used to compare the proposed approach with state of the art approaches. The quantitative comparison showed that the proposed approach achieved the highest average F-measure accuracy, 95.61 %. Thus, the proposed approach has the potential to be useful for various microscopic applications. [ABSTRACT FROM AUTHOR]

Let t a and t b be a pair of relatively prime positive integers. We work on chains of n ( t a + t b ) agents which form together an upper and rightward directed path of the grid Z 2 from O = ( 0 , 0 ) to M = ( n t a , n t b ) . We are interested on evolution rules such that, at each time step, an agent is randomly chosen on the chain and is allowed to jump to another site of the grid preserving the connectivity of the chain and the endpoints. The rules must be local, i.e. , the decision of jumping or not only depends on the neighborhood of fixed size s of the randomly chosen agent, and not on the parameters t a , t b , n . Moreover, the parameter s only depends on t a + t b and not on n . In this paper, we design a rule such that, starting from any chain which does not cross the continuous line segment [ O , M ] , this rule reorganizes this chain into one of the best possible approximations of [ O , M ] . The stabilization is reached after O ( ( n ( t a + t b ) ) 4 ) iterations, in average. The work presented here is at the crossroad of many different domains such as modeling a stabilizing process in crystallography, stochastic cellular automata, organizing a line of robots in distributed algorithms (the robot chain problem) and Christoffel words in language theory. [ABSTRACT FROM AUTHOR]

The development of highly specific and ultrasensitive fluorescent probes for tracking basal mitochondrial hypochlorite is very important to unravel its diverse cellular functions in the mitochondria of living cells. In this paper, we have developed a water-soluble, mitochondria-targeted near-infrared fluorescent probe NB-OCl for selectively measuring OCl - in the presence of higher concentration (500 μM) other biologically important substances. Surprisingly, the obtained results demonstrated that probe NB-OCl could sensitively determine OCl - in the range of 0–200 pM with the detection limit of 10.8 pM. To the best of our knowledge, NB-OCl is the first fluorescent probe for the specific determination of OCl - at the picomolar level. Moreover, probe NB-OCl exhibits a fast response for OCl - (< 5 s), which would be in favor of tracking the highly reactive and short-lived OCl - in the living systems. The preeminent recognition properties of probe NB-OCl enable its applications in the monitoring of basal OCl - and the fluctuations of endogenous/exogenous OCl - levels in the mitochondria of living cells. [ABSTRACT FROM AUTHOR]

In this paper, a cognitive machine-to-machine (CM2M) network is considered in which underlaid on a macro cell, there exist some co-existing small cell based M2M networks. In each small cell, M2M network is comprised of some machine type devices (MTDs) and an MTD gateway. The MTD gateway collects data of MTDs within each small cell and transmits it to the small cell base station reusing the spectrum of the macro cell. To avoid data loss, MTD gateway is equipped with a buffer. In the considered CM2M network, MTDs with delay sensitive application are prioritized over MTDs having delay tolerant packets. In order to minimize the average delay of the MTDs, a novel packet adjustment scheme is proposed. The average delay and the average throughput of the CM2M network are computed. Simulation results show that the proposed scheme outperforms conventional policy without packet adjustment in terms of average delay of MTDs. [ABSTRACT FROM AUTHOR]

• High-fidelity generalized method of cells (HFGMC) is computationally expensive. • The use of reformulation and sparse matrices improved efficiency. • High-resolution analyses are now possible using HFGMC. • High-resolution micromechanical analysis is necessary for complex microstructures. The high-fidelity generalized method of cells (HFGMC) enables micromechanical analysis of heterogeneous materials with high accuracy but does so at the cost of computational efficiency. In this paper, an implementation of the triply periodic HFGMC is developed to enable high-resolution simulations of materials with complex microstructures at a significantly reduced computational cost. This paper describes efficient reformulation and develops low-cost algorithms to reduce overall computation time and memory required to analyze complex 3D microstructures. The low-cost algorithms exploit the sparsity of the data by storing and performing calculations on only the non-zero values. The Parallel Direct Sparse Solver (PARADISO) subroutine is used to execute the most computationally intensive processes in parallel on multiple cores. Simulations of two selected test cases demonstrate the validity, computational efficiency, and value of the developed implementation. The results indicate that the savings in computation time and required memory are substantial and more than 100 times in some cases. In addition, parallel processing further reduces the computation time. The efficiency achieved through this work makes the high-resolution simulation of complex microstructures using HFGMC for the prediction of accurate local stress/strain fields computationally feasible. [ABSTRACT FROM AUTHOR]

• Implementation of cell-based three-input XOR and two-to-one multiplexer as ultra-efficient building blocks in QCA. • They are implemented based on Coulombic interactions between quantum-dot cells. • They are really compact and novel, designed using only very few QCA cells. • They are used for implementing full-adders and four-bit adders to demonstrate their performance. In the quantum-dot cellular automata (QCA) nanotechnology, the cell-based building block can be designed by utilizing the charge reconfiguration of quantum-dot cells in order to achieve the desired function with optimal implementation. In this paper, new advanced nanostructures based on quantum-dot cells are introduced to three-input XOR gate and two-to-one multiplexer, which can be considered in addition to the conventional majority voter as basic building blocks used in implementing well-optimized QCA circuits. Consequently, these blocks are used in this paper to implement new single-layer QCA full-adders and four-bit adders as motivational applications. Moreover, an innovative design approach of full-adder is proposed to avoid the presence of inputs surrounded by QCA cells and to prevent the use of crossovers when building multi-bit adders. The proposed QCA layouts are simulated and evaluated as results indicate that proposed designs are superior to the previous designs in the literature. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The use of semantic technologies, such as ontologies, to describe and analyse biological systems is at the heart of systems biology. Indeed, understanding the behaviour of cells requires a large amount of context information. In this paper, we propose an ontology entitled ”Biomolecular Network ontology” using the OWL language. The BNO ontology standardises the terminology used by biologists experts to address issues including semantic behaviour representation, reasoning and knowledge sharing. The main benefit of this proposed ontology is the ability to reason about dynamical behaviour of complex biomolecular networks over time. We demonstrate our proposed ontology with a detailed example, the bacteriophage T4 gene 32 use case. [ABSTRACT FROM AUTHOR]

Nowadays, the demand for segmenting different types of cells imaged by microscopes is increased tremendously. The requirements for the segmentation accuracy are becoming stricter. Because of the great diversity of cells, no traditional methods could segment various types of cells with adequate accuracy. In this paper, we aim to propose a generic approach that is capable of segmenting various types of cells robustly and counting the total number of cells accurately. To this end, we utilize the gradients of cells instead of intensity for cell segmentation because the gradients are less affected by the global intensity variations. To improve the segmentation accuracy, we utilize the Gabor filter to increase the intensity uniformity of the gradient image. To get the optimal segmentation, we utilize the slope difference distribution based threshold selection method to segment the Gabor filtered gradient image. At last, we propose an area-constrained ultimate erosion method to separate the connected cells robustly. Twelve types of cells are used to test the proposed approach in this paper. Experimental results showed that the proposed approach is very promising in meeting the strict accuracy requirements for many applications. [ABSTRACT FROM AUTHOR]

Large Li-ion battery packs are an enabling technology for electric vehicles, smart homes and the smart grid. Keeping the individual cells that make up the battery pack balanced reduces the loss of capacity over time and reduces the chances of damaging the pack by over charging/discharging cells. This paper presents a review of the basic charge equalisation circuits categorised as capacitor, inductor or transformer based. The paper highlights improvements and variations made to these basic circuits by researchers and provides a general comparison. The paper proceeds to discuss the difficulties in directly comparing performance of different CECs (charge equalisation circuit) and the ambiguity of the industrial requirements of a CEC. Finally the paper presents possible areas of research to further improve the charge equalisation process. • Categorises and reviews cell equalisations circuits. • Advantages and disadvantages of inductor, capacitor and transformer topologies. • Comments on specific examples and variations by authors. • Discusses issues within the research field, suggests future research directions. [ABSTRACT FROM AUTHOR]

• Novel phenothiazine-based colorimetric and ratiometric fluorescent sensor PPM for Hg2+ is synthesized. • PPM shows high selectivity and low detection limit of 12.5 nM in a wide pH range. • The response time of PPM for Hg2+ is within 1 min and suitable for ultrafast detection of Hg2+. • PPM for Hg2+ shows good applicability for paper/TLC-based "naked-eye" colorimetric assay. • PPM was used for fluorescence imaging of Hg2+ in living cells. A new phenothiazine-based sensor PPM was successfully designed and synthesized, which shows highly selective, ultrafast, naked-eye colorimetric and turn-on ratiometric fluorescence sensing of Hg2+ on the basis of the ICT from phenothiazine to aldehyde. Upon addition of Hg2+, obvious blue fluorescence at 455 nm decreased while green fluorescence at 528 nm enhanced, which exhibits ratiometric fluorescent turn-on response along with a "naked-eye" color change from pale-blue to bright-green. The PPM for highly sensing of Hg2+ with a quite low detection limit (12.5 nM) and a wide pH application range. The sensing mechanism proved to be the Hg2+-triggered thioacetal deprotection reaction was confirmed. Importantly, PPM was successfully employed for highly selective detecting and imaging of Hg2+ in living cells, as well as on paper/TLC-based "naked-eye" colorimetric assay. [ABSTRACT FROM AUTHOR]

Microcapsule entrapped low density cells with culture (ELDC wc ), different from free cell culture, conferred stronger stress resistance and improved cell viability of microorganisms. In this paper, the quorum sensing (QS) system of Vibrio harveyi was used to investigate changes when cells were cultured in microcapsules. Cells in ELDC wc group grew into cell aggregates, which facilitated cell–cell communication and led to increased bioluminescence intensity. Moreover, the luxS -AI-2 system, a well-studied QS signal pathway, was detected as both luxS gene and the AI-2 signaling molecule, and the results were analyzed with respect to QS capacity of unit cell. The V. harveyi of ELDC wc also showed higher relative gene expression and stronger quorum sensing capacity when compared with free cells. In conclusion, the confined microcapsule space can promote the cell aggregates formation, reduce cell–cell communication distance and increase local concentration of signal molecule, which are beneficial to bacterial QS. [ABSTRACT FROM AUTHOR]

Objective The present paper aims to investigate the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and N-nitrosodiethylamine (DEN) on tumorigenesis and its potential mechanism. Methods The potentials of TCDD and DEN in separation or in combination to induce malignant transformation were tested in Balb/c 3T3 cells by using a cell transformation assay method. The possible mechanism of observed effects was studied further by adding ct-naphthoflavone (α-NF), a competitive binding agent of TCDD, to the Aryl hydrocarbon receptor (AhR) pathway. The mRNA expressions of Cyplal and Cyp2a5 gene in Balb/c 3T3 cells treated by DEN and TCDD in separation or in combination with or without presence of α-NF were measured with fluorescence quantification RT-PCR technique. Results The cell transformation frequency (TF) was significantly higher in case of induction with TCDD in combination with DEN, as compared to that with either TCDD or DEN alone. These effects were not inhibited via α-NF. The mRNA expression levels of both Cyplal and Cyp2a5 were enhanced by TCDD treatment alone, but this inducible effect was blocked in cells treated by TCDD and DEN in combination. Conclusion TCDD and DEN had a significant synergistic effect on tumorigenesis when they were used in combination. AhR pathway may not be the key mechanism of this synergistic effect. Thus, it is necessary to further test the potential mechanism involved in cancer development. [ABSTRACT FROM AUTHOR]

Abstract: Living cells can be modelled by successively imposing known constraints that limit their behaviour, such as mass balances, thermodynamic laws or enzyme capacities. The resulting constraint-based models enclose all the functional states that the modelled cells may exhibit. Then, predictions can be obtained from the models in two main ways: adding experimental data to determine the state of cells at given conditions (MFA) or invoking an assumption of evolved optimal behaviour (FBA). Both MFA and FBA predictions are typically performed at steady state. However, it is easy to take extracellular dynamics into account. This work explores the benefits of using possibility theory to get these dynamic predictions. It will be shown that the possibilistic methods (a) provide rich estimates for time-varying fluxes and metabolite concentrations, (b) account for uncertainty and data scarcity, and (c) give predictions relaxing the optimality assumption of FBA. On the other hand, these methods could serve as basis for monitoring and fault detection systems in industrial bioprocesses. [Copyright &y& Elsevier]

Abstract: Cell formation consists in organizing a plant as a set of cells, each of them containing machines that process similar types or families of parts. The idea is to minimize the part flow among cells in order to reduce costs and increase productivity. The literature presents different approaches devoted to solve this problem, which are mainly based on mathematical programming and on evolutionary computing. Mathematical programming can guarantee a global optimal solution, however at a higher computational cost than an evolutionary algorithm, which can assure a good enough optimum in a fixed amount of time. In this paper, we model and solve this problem by using state-of-the-art constraint programming (CP) techniques and Boolean satisfiability (SAT) technology. We present different experimental results that demonstrate the efficiency of the proposed optimization models. Indeed, CP and SAT implementations are able to reach the global optima in all tested instances and in competitive runtime. [Copyright &y& Elsevier]

Abstract: It is possible that the nucleolous inside the cell plays the role of a “gravity receptor”. Furthermore, cells up to 10μm in diameter can demonstrate some effect due to the redistribution of mitochondria or nucleolous. Effects of gravity should be present in various cell systems where larger objects such as the ribosomes move from cell to cell. In this paper we study the effects of gravity on cells. In particular, we examine the resulting intracellular molecular distribution due to Brownian motion and the ordered distribution of molecules under the action of gravity, where n 0 is the number per unit volume at certain level, and n is the number per unit volume above that level. This is an experiment that takes place at a certain orbital altitude in a spacecraft in orbit around Earth, where the acceleration due to the central field is corrected for the oblateness and also the rotation of the Earth. We found that equatorial circular and elliptical orbits have the highest n/n 0 ratios. This experiment takes place in circular and elliptical orbits, with eccentricities e =0, 0.1 and involves a bacterial cell at an orbital altitude of 300km. We found that n/n 0 =1.00299 and 1.0037 respectively, which is still a 0.6–0.7 % higher than n/n 0 =0.0996685 calculated on the surface of the Earth. Examining mitochondria in similar orbital experiments we found that equatorial orbits result to higher n/n 0 ratios. In particular, we found that n/n 0 =8.38119, where an elliptical orbit of eccentricity e =0.1 results to n/n 0 =13.8525. Both are high above 100%, signifying the importance of Brownian motion over gravity. Our results are of interest to biomedical applications. Molecular concentrations are important for various processes such as the embryogenesis, positional homeostasis and its relation to cell energy expenditure, cell torque, cell deformation, and more. These results indicate that statistical molecular distributions play an important role for the recognition of a particular environment by the cell, in biological space experiment to come. [Copyright &y& Elsevier]

Abstract: Single cell was capable of sensing and responding to alterations of gravity. Osteocytes, as the most abundant cells of the bone tissue playing an important role in the bone mechanotransduction, are very sensitive to mechanical stimuli. However, the effect of altered gravity on osteocytes so far is less known according to the public papers. Further study on this issue will help to verify and develop the theory of how cells perceive and respond to gravity. It also brings new ideas to the study of space bone loss. In our study, Osteocyte-like MLO-Y4 cells were exposed to 30 parabolic flights three times on ZERO-G airbus A300 to investigate the comprehensive effect on osteocytes stimulated by hyper- and hypo-gravity forces. It showed that the cell morphology, as well as cell area and height, was not changed significantly by hyper-gravity and hypo-gravity. However, the cytoskeleton was reorganized. In flight cells, F-actin polymerization was enhanced at the cell periphery and microtubule organizing center disappeared, but no apoptotic feathers were detected. The results of western blot showed that connexin 43 (Cx43) expression was down-regulated, indicating an decrease of gap-junction. In conclusion, hyper- and hypo-gravity stimulation altered the cytoskeleton architecture and suppressed gap-junction of osteocyte-like MLO-Y4 cells. [Copyright &y& Elsevier]

Abstract: Biochemical oxygen demand (BOD) is one of the most important and widely used parameters for characterizing the organic pollution of water and wastewater. In this paper, a novel reactor-type biosensor for rapid measurement of BOD was developed, based on using immobilized microbial cell (IMC) beads as recognition bio-element in a completely mixed reactor which was used as determining chamber, replacing the traditionally used membrane as recognition bio-element. The IMC beads were freely suspended in the aqueous solution, so the mass transfer resistance for dissolved oxygen and organic compounds significantly reduced, and the quantity of the microbial cells used as recognition element can be easily adjusted, in comparison with the traditional membrane-type BOD biosensor, in which exists a unadjustable contradiction between the quantity of biomass and the thickness of the bio-membrane, thus limiting the stability and the detection limit. This novel kind of BOD biosensor significantly increased the sensitivity of the response, the detecting precision and prolonged the life time of the recognition element. The experimental data showed that the most appropriate temperature for biochemical reaction in the reactor was 30°C, and the IMC beads could keep the bioactivity for about 70d at the detecting frequency of 8 times every day. The standard deviation of repeatability and the reproducibility of responses were within ±6.4% and ±5.0%, respectively, which are within acceptable bias limits, and meet the requirement of BOD rapid measurement. [Copyright &y& Elsevier]

Abstract: Studies of cells in silico can greatly reduce the need for expensive and prolonged laboratory experimentation. The use of model checking for the analysis of biological networks has attracted much attention recently. The practical limitations are still the size of the model, and the time needed to generate the state space. This paper is focused on the model checking approach for analysis of piecewise-linear deterministic models of genetic regulatory networks. Firstly, the qualitative simulation algorithm of de Jong et al. that builds the heart of Genetic Network Analyzer (GNA) is revisited and its time complexity is studied in detail. Secondly, a novel algorithm that reduces the state space generation time is introduced. The new algorithm is developed as an abstraction of the original GNA algorithm. Finally, a fragment of linear time temporal logic for which the provided abstraction is conservative is identified. Efficiency of the new algorithm when implemented in the parallel model checking environment is demonstrated on a set of experiments performed on randomly modified biological models. In general, the achieved results bring a new insight into the field of qualitative simulation emerging in the context of systems biology. [Copyright &y& Elsevier]

Abstract: Uniform patterning of cells is highly desirable for most cellular studies involving cell–cell interactions but is often difficult in an in vitro environment. This paper presents the development of a collagen-coated planar interdigitated ring electrode (PIRE) array utilizing positive dielectrophoresis to pattern cells uniformly. Key features of the PIRE design include: (1) maximizing length along the edges where the localized maximum in the electric field exists; (2) making the inner gap slightly smaller than the outer gap in causing the electric field strength near the center of a PIRE being generally stronger than that near the outer edge of the same PIRE. Results of human hepatocellular carcinoma cells, HepG2, adhered on a 6×6 PIRE array show that cells patterned within minutes with good uniformity (48±6 cells per PIRE). Cell viability test revealed healthy patterned cells after 24h that were still confined to the collagen-coated PIREs. Furthermore, quantification of fluorescence intensity of living cells shows an acceptable reproducibility of cell viability among PIREs (mean normalized intensity per PIRE was 1±0.138). The results suggest that the PIRE array would benefit applications that desire uniform cellular patterning, and improve both response and reproducibility of cell-based biosensors. [Copyright &y& Elsevier]

Obtaining pigmentary function in autologous skin grafts is a current challenge for burn surgeons as is developing reliable robust grafting strategies for patients with vitiligo and piebaldism. In this paper, we present the development of a simple methodology for delivering cultured keratinocytes and melanocytes to the patient that is of low risk for the patient but also user friendly for the surgeon. In this study, we examined the ability of keratinocytes and melanocytes to transfer from potential cell carriers under different media conditions to an in vitro human wound bed model. The number of melanocytes transferred, their location within the neoepidermis, and their ability to pigment were evaluated as preclinical end points. Two inert substrates (polyvinyl chloride and silicone sheets) and three candidate plasma-polymerized coatings with controlled surface chemistry deposited on these substrates were explored. Two media for expansion of cells, Greens, currently used clinically (but which contains fetal calf serum), and a serum-free alternative, M2 (melanocyte medium), were explored. Reproducible transfer of physiologically relevant numbers of melanocytes capable of pigmentation from the coculture of melanocytes and keratinocytes was obtained using either Greens medium or M2 medium, and a silicone carrier pretreated with 20% carboxylic acid deposited by plasma polymerization.Journal of Investigative Dermatology (2008) 128, 1554–1564; doi:10.1038/sj.jid.5701214; published online 17 January 2008 [ABSTRACT FROM AUTHOR]

Abstract: Gliomas are one of the most malignant cancers. The molecular bases regulating the onset of such tumors are still poorly understood. The translocator protein (TSPO), formerly known as the peripheral-type benzodiazepine receptor, is a mitochondrial permeability transition (MPT)-pore protein robustly expressed in gliomas and involved in the regulation of apoptosis and cell proliferation. TSPO expression levels have been correlated with tumor malignancy. Here we describe the production of C6 rat glioma cells engineered to over-express the TSPO protein with the aim of providing the first direct evidence of a correlation between TSPO expression level and glioma cell aggressiveness. We observed that TSPO potentiates proliferation, motility and transmigration capabilities as well as the ability to overcome contact-induced cell growth inhibition of glioma cells. On the whole, these data demonstrate that TSPO density influences metastatic potential of glioma cells. Since several data suggest that TSPO ligands may act as chemotherapeutic agents, in this paper we also demonstrate that TSPO ligand-induced cell death is dependent on TSPO density. These findings suggest that the use of TSPO ligands as chemotherapeutic agents could be effective on aggressive tumor cells with a high TSPO expression level. [Copyright &y& Elsevier]

Abstract: This paper reports on the application of surface chemical gradients to study mammalian cell interactions with synthetic surfaces and investigates if the cell response on certain parts of the gradient is the same as that on uniform surfaces of equivalent chemistry. The gradients, formed using a diffusion-controlled plasma polymerisation technique, were fabricated such that cell response to a large range of different chemistries on a single sample could be investigated. Surface chemical gradients from hydrophobic plasma polymerised hexane (ppHex) to a more hydrophilic plasma polymerised allylamine (ppAAm), previously used to control cell density within 3D tissue-engineering scaffolds, were formed on glass coverslips. Surface characterisation was carried out to determine water contact angles (WCA), elemental composition, coating thickness and topography of the chemical gradients. Cell response was assessed following culture of 3T3 fibroblasts on both steep and shallow gradients. Fibroblasts adhered and proliferated preferentially on ppAAm (WCA∼60°) showing a gradual decreasing cell density towards the hydrophobic ppHex (WCA∼93°). Experiments on a uniform ppAAm surface revealed that there was a significant difference in cell density when compared to the gradient samples. The initial number of cells that adhered to the surface was confirmed as the difference between the uniform and graduated ppAAm samples, and it is assumed that this difference relates to different cell–cell signalling processes and/or greater protein production from surrounding cells on these two samples formats. [Copyright &y& Elsevier]

Abstract: In industrial production lines, for example in the automotive industry, cells with multiple industrial robots are common. In such cells, each robot has to avoid running into static obstacles and when the robots work together in a shared space they must also avoid colliding with each other. Typically, the latter is enforced by manually implementing interlocks in programmable logic controllers (PLCs). This is a tedious, error-prone task that is a bottleneck in the development of production lines. The PLC-code being man-made also greatly complicates the maintenance and reconfiguration of such production lines. However, in industry today, a lot of development of robot cells is made offline in 3D simulation environments which enables the use of computers also for deciding and implementing the necessary coordination. This paper presents a method that makes use of information in a robot simulation environment in order to automatically extract finite state models. These models can be used to generate supervisors for ensuring that the deadlock situations that may arise as a consequence of the introduced interlocks are avoided. It is also possible to optimize the work cycle time for the cell. Finally, PLC-code to supervise the production cell can be automatically generated from the deadlock-free and possibly optimized system model. This approach results in a high flexibility in that the coordination function can be quickly reimplemented whenever necessary. A prototype implementation has been developed making use of a commercial 3D robot simulation tool, and a software tool for supervisor synthesis and code generation. The approach is general and should be possible to implement in most offline robot simulation tools. [Copyright &y& Elsevier]

Abstract: The knowledge of the mechanical behaviour of woven fabrics is necessary in many applications in particular for the simulation of textile composite forming. This mechanical behaviour is very specific due to the possible motions between the fibres and the yarns. In this paper, the in-plane shear behaviour is analysed from virtual tests on the Representative Unit Cell. The in-plane shear strains can be very large (up to 50°) in case of draping on a double curved surface. These virtual tests avoid performing tricky experimental tests. The presented 3D finite element analyses involve two main specific aspects. Firstly the boundary conditions have to render the periodicity at large deformations and, in some cases, the evolution of contacts between neighbouring yarns during the motion. Secondly the yarn that is made of thousand of fibres is modelled as a continuous medium but its constitutive law has to take its fibrous nature into account. For that reason a rate constitutive equation using a specific objective stress rate is used. It is based on the rotation of the fibre. The analysis is performed for two unit cells. Both results are in good agreement with the experiments, but the use of one of the cells turns out to be much easier. [Copyright &y& Elsevier]