scholarly journals Director Reorientation in a Cell with Time-Dependent Anchoring Due To Adsorption/Desorption of LC Molecules

2004 ◽  
Vol 422 (1) ◽  
pp. 173-183 ◽  
Author(s):  
Alexander Romanenko ◽  
Igor Pinkevich ◽  
Victor Reshetnyak ◽  
Ivan Dozov ◽  
Daniel Stoenescu
Keyword(s):  
Time Dependent ◽  
A Cell ◽  
Director Reorientation ◽  
Adsorption Desorption

Magnetic Field Induced Director Reorientation in the Nematic Cell with Time-Dependent Anchoring Due to Adsorption/Desorption of LC Molecules

2005 ◽  
Vol 439 (1) ◽  
pp. 1/[1867]-22/[1888] ◽  
Author(s):  
Alexander Romanenko ◽  
Victor Reshetnyak ◽  
Igor Pinkevich ◽  
Ivan Dozov ◽  
Sandro Faetti
Keyword(s):  
Magnetic Field ◽  
Time Dependent ◽  
Director Reorientation ◽  
Adsorption Desorption

MODELLING NITROGEN PROCESSES IN SOIL: MATHEMATICAL DEVELOPMENT AND RELATIONSHIPS

1976 ◽  
Vol 56 (2) ◽  
pp. 71-78 ◽  
Author(s):  
D. R. CAMERON ◽  
C. G. KOWALENKO
Keyword(s):  
Time Dependent ◽  
Rate Coefficients ◽  
Nitrification Rate ◽  
Order Kinetic ◽  
Nitrogen Flow ◽  
First Order ◽  
Interaction Term ◽  
Flow Pathways ◽  
Adsorption Desorption ◽  
Temperature Water

A small subsystem model was developed to simulate the major nitrogen flow pathways in an unsaturated soil treated with ammonium sulphate. A nonlinear Freundlich equilibrium model and a Langmuir kinetic model were used to describe mathematically the adsorption–desorption of soluble NH4+ to the exchangeable and clay-fixed phases, respectively. Time dependent, microbial mediated first-order kinetic models were used to quantify the ammonification and nitrification processes. The subsystem model was then used as a research tool to derive ammonification and nitrification rate coefficients for a preceding incubation experiment conducted using different soil moisture contents and temperatures. The model yields reasonably good fits to the observed data. A subsequent regression analysis relating the coefficients to temperature and moisture pointed out the importance of the temperature–water content interaction term in quantifying microbial mediated processes.

scholarly journals Delayed self-regulation and time-dependent chemical drive leads to novel states in epigenetic landscapes

2014 ◽  
Vol 11 (100) ◽  
pp. 20140706 ◽  
Author(s):  
Mithun K. Mitra ◽  
Paul R. Taylor ◽  
Chris J. Hutchison ◽  
T. C. B. McLeish ◽  
Buddhapriya Chakrabarti
Keyword(s):  
Single Gene ◽  
Self Regulation ◽  
Time Dependent ◽  
Sustained Oscillations ◽  
Regulatory Circuit ◽  
Oscillatory State ◽  
A Cell ◽  
The Hill ◽  
Stem Cell State

The epigenetic pathway of a cell as it differentiates from a stem cell state to a mature lineage-committed one has been historically understood in terms of Waddington's landscape, consisting of hills and valleys. The smooth top and valley-strewn bottom of the hill represent their undifferentiated and differentiated states, respectively. Although mathematical ideas rooted in nonlinear dynamics and bifurcation theory have been used to quantify this picture, the importance of time delays arising from multistep chemical reactions or cellular shape transformations have been ignored so far. We argue that this feature is crucial in understanding cell differentiation and explore the role of time delay in a model of a single-gene regulatory circuit. We show that the interplay of time-dependent drive and delay introduces a new regime where the system shows sustained oscillations between the two admissible steady states. We interpret these results in the light of recent perplexing experiments on inducing the pluripotent state in mouse somatic cells. We also comment on how such an oscillatory state can provide a framework for understanding more general feedback circuits in cell development.

scholarly journals Uranium diffusion and time‐dependent adsorption–desorption in soil: A model and experimental testing of the model

2019 ◽  
Vol 71 (2) ◽  
pp. 215-225
Author(s):  
Jana Darmovzalova ◽  
Andrea Boghi ◽  
Wilfred Otten ◽  
Lorna J. Eades ◽  
Tiina Roose ◽  
...  
Keyword(s):  
Experimental Testing ◽  
Time Dependent ◽  
Adsorption Desorption

scholarly journals Gene Expression Profiling of Leiomyoma and Myometrial Smooth Muscle Cells in Response to Transforming Growth Factor-β

Endocrinology ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 1097-1118 ◽  
Author(s):  
Xiaoping Luo ◽  
Li Ding ◽  
Jingxia Xu ◽  
Nasser Chegini
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Gene Expression Profile ◽  
Expression Profile ◽  
Binding Protein ◽  
Muscle Cells ◽  
Time Dependent ◽  
Early Gene ◽  
A Cell

Altered expression of the TGF-β system is recognized to play a central role in various fibrotic disorders, including leiomyoma. In this study we performed microarray analysis to characterize the gene expression profile of leiomyoma and matched myometrial smooth muscle cells (LSMC and MSMC, respectively) in response to the time-dependent action of TGF-β and, after pretreatment with TGF-β type II receptor (TGF-βRII) antisense oligomer-blocking/reducing TGF-β autocrine/paracrine actions. Unsupervised and supervised assessments of the gene expression values with a false discovery rate selected at P ≤ 0.001 identified 310 genes as differentially expressed and regulated in LSMC and MSMC in a cell- and time-dependent manner by TGF-β. Pretreatment with TGF-βRII antisense resulted in changes in the expression of many of the 310 genes regulated by TGF-β, with 54 genes displaying a response to TGF-β treatment. Comparative analysis of the gene expression profile in TGF-βRII antisense- and GnRH analog-treated cells indicated that these treatments target the expression of 222 genes in a cell-specific manner. Gene ontology assigned these genes functions as cell cycle regulators, transcription factors, signal transducers, tissue turnover, and apoptosis. We validated the expression and TGF-β time-dependent regulation of IL-11, TGF-β-induced factor, TGF-β-inducible early gene response, early growth response 3, CITED2 (cAMP response element binding protein-binding protein/p300-interacting transactivator with ED-rich tail), Nur77, Runx1, Runx2, p27, p57, growth arrest-specific 1, and G protein-coupled receptor kinase 5 in LSMC and MSMC using real-time PCR. Together, the results provide the first comprehensive assessment of the LSMC and MSMC molecular environment targeted by autocrine/paracrine action of TGF-β, highlighting potential involvement of specific genes whose products may influence the outcome of leiomyoma growth and fibrotic characteristics by regulating inflammatory response, cell growth, apoptosis, and tissue remodeling.

Gelatinase B and TIMP-1 are regulated in a cell- and time-dependent manner in association with neuronal death and glial reactivity after global forebrain ischemia

2002 ◽  
Vol 15 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Santiago Rivera ◽  
Crystel Ogier ◽  
Jérôme Jourquin ◽  
Serge Timsit ◽  
Arkadius W. Szklarczyk ◽  
...  
Keyword(s):  
Neuronal Death ◽  
Time Dependent ◽  
Dependent Manner ◽  
Forebrain Ischemia ◽  
Gelatinase B ◽  
A Cell ◽  
Glial Reactivity

Dynamic of Surface-Mediated Director Reorientation in a Cell with Dye Doped Liquid Crystal

2004 ◽  
Vol 421 (1) ◽  
pp. 235-242 ◽  
Author(s):  
D. Fedorenko∗ ◽  
E. Ouskova ◽  
Yu. Reznikov ◽  
V. Reshetnyak ◽  
L. Lucchetti ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
A Cell ◽  
Director Reorientation

scholarly journals Orientational instability of the director in a nematic cell caused by electro-induced anchoring modification

2021 ◽  
Vol 24 (1) ◽  
pp. 13601
Author(s):  
O.S. Tarnavskyy ◽  
M.F. Ledney
Keyword(s):  
Liquid Crystal ◽  
Negative Ions ◽  
The Other ◽  
Cell Surfaces ◽  
Positive Ions ◽  
Threshold Voltages ◽  
A Cell ◽  
Director Reorientation ◽  
Orientational Transitions

We theoretically investigate the threshold for the director reorientation from the homeotropic state to the hybrid homeotropic-planar state and vice versa in a cell filled with a flexoelectric nematic liquid crystal (NLC) subjected to an electric field. The liquid crystal is doped by a CTAB-like substance, a part of molecules of which dissociates into positive and negative ions. The anchoring on one of the cell surfaces is assumed to be strong and homeotropic, while the other surface can adsorb positive ions which play the role of an orienting surfactant for NLC molecules on this surface. At certain voltages, the orientational transitions in the bulk of the NLC are possible due to the changing conditions for the director on the adsorbing surface. We calculate respective threshold voltages as functions of anchoring parameters. The existence of the critical values of these parameters, beyond which the orientational transitions do not take place, is established.

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