Crossover of Rate-Limiting Process in Plasma Gel Growth by Contact with Source of Gelator

Plasma is regarded as a solution of precursor polymers specifically transformed to gel-forming polymers by a reaction with initiators. We developed a theory for the gel growth dynamics of plasma induced by contact with a source of gelators that are yielded by the initiation. In developing the theory, we combined the Ginzburg–Landau type dynamics with the gelator diffusion dynamics expressed by the moving boundary picture. The theory predicts the crossover of the rate-limiting process in the time course of the thickness of the gel layer X from the energy-limited process expressed by X∼t to the diffusion-limited process expressed by X∼t, where t is the time elapsed from when the plasma comes into contact with the source of gelators. A demonstration experiment was performed by placing a tissue factor coating plate as the initiator in plasma. Log–log plot of X vs. t showed a crossover as predicted by the theory, and the parameters characterizing plasma were determined.

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In Situ Monitoring of Cement Gel Growth Dynamics. Use of a Miniaturized Permanent Halbach Magnet for Precise1H NMR Studies

Industrial & Engineering Chemistry Research ◽

10.1021/ie901255b ◽

2010 ◽

Vol 49 (2) ◽

pp. 613-622 ◽

Cited By ~ 8

Author(s):

Eleni Karakosta ◽

George Diamantopoulos ◽

Marios S. Katsiotis ◽

Michael Fardis ◽

Georgios Papavassiliou ◽

...

Keyword(s):

Growth Dynamics ◽

In Situ Monitoring ◽

Gel Growth ◽

Nmr Studies

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Data-driven multiscale modeling reveals the role of metabolic coupling for the spatio-temporal growth dynamics of yeast colonies

10.1101/344226 ◽

2018 ◽

Author(s):

Jukka Intosalmi ◽

Adrian C. Scott ◽

Michelle Hays ◽

Nicholas Flann ◽

Olli Yli-Harja ◽

...

Keyword(s):

Experimental Data ◽

Time Course ◽

Model Development ◽

Growth Dynamics ◽

Colony Growth ◽

Data Driven ◽

Coarse Grained ◽

Intercellular Signaling ◽

Growth Data ◽

Metabolic Coupling

AbstractMotivationMulticellular entities, such as mammalian tissues or microbial biofilms, typically exhibit complex spatial arrangements that are adapted to their specific functions or environments. These structures result from intercellular signaling as well as from the interaction with the environment that allow cells of the same genotype to differentiate into well-organized communities of diversified cells. Despite its importance, our understanding on how cell–cell and metabolic coupling produce functionally optimized structures is still limited.ResultsHere, we present a data-driven spatial framework to computationally investigate the development of one multicellular structure, yeast colonies. Using experimental growth data from homogeneous liquid media conditions, we develop and parameterize a dynamic cell state and growth model. We then use the resulting model in a coarse-grained spatial model, which we calibrate using experimental time-course data of colony growth. Throughout the model development process, we use state-of-the-art statistical techniques to handle the uncertainty of model structure and parameterization. Further, we validate the model predictions against independent experimental data and illustrate how metabolic coupling plays a central role in colony formation.AvailabilityExperimental data and a computational implementation to reproduce the results are available athttp://research.cs.aalto.fi/csb/software/multiscale/[email protected],[email protected]

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Data-driven multiscale modeling reveals the role of metabolic coupling for the spatio-temporal growth dynamics of yeast colonies

BMC Molecular and Cell Biology ◽

10.1186/s12860-019-0234-z ◽

2019 ◽

Vol 20 (1) ◽

Author(s):

Jukka Intosalmi ◽

Adrian C. Scott ◽

Michelle Hays ◽

Nicholas Flann ◽

Olli Yli-Harja ◽

...

Keyword(s):

Experimental Data ◽

Time Course ◽

Growth Dynamics ◽

Colony Growth ◽

Data Driven ◽

Coarse Grained ◽

Colony Development ◽

Intercellular Signaling ◽

Metabolic Coupling ◽

The Impact

Abstract Background Multicellular entities like mammalian tissues or microbial biofilms typically exhibit complex spatial arrangements that are adapted to their specific functions or environments. These structures result from intercellular signaling as well as from the interaction with the environment that allow cells of the same genotype to differentiate into well-organized communities of diversified cells. Despite its importance, our understanding how this cell–cell and metabolic coupling lead to functionally optimized structures is still limited. Results Here, we present a data-driven spatial framework to computationally investigate the development of yeast colonies as such a multicellular structure in dependence on metabolic capacity. For this purpose, we first developed and parameterized a dynamic cell state and growth model for yeast based on on experimental data from homogeneous liquid media conditions. The inferred model is subsequently used in a spatially coarse-grained model for colony development to investigate the effect of metabolic coupling by calibrating spatial parameters from experimental time-course data of colony growth using state-of-the-art statistical techniques for model uncertainty and parameter estimations. The model is finally validated by independent experimental data of an alternative yeast strain with distinct metabolic characteristics and illustrates the impact of metabolic coupling for structure formation. Conclusions We introduce a novel model for yeast colony formation, present a statistical methodology for model calibration in a data-driven manner, and demonstrate how the established model can be used to generate predictions across scales by validation against independent measurements of genetically distinct yeast strains.

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Role of mechanical cues and hypoxia on the growth of tumor cells in strong and weak confinement: A dual in vitro–in silico approach

Science Advances ◽

10.1126/sciadv.aaz7130 ◽

2020 ◽

Vol 6 (13) ◽

pp. eaaz7130 ◽

Cited By ~ 1

Author(s):

V. Le Maout ◽

K. Alessandri ◽

B. Gurchenkov ◽

H. Bertin ◽

P. Nassoy ◽

...

Keyword(s):

In Silico ◽

Time Course ◽

Growth Dynamics ◽

Tumor Model ◽

Mechanistic Modeling ◽

Physical Factors ◽

Factors Affecting ◽

Numerical Studies

Characterization of tumor growth dynamics is of major importance for cancer understanding. By contrast with phenomenological approaches, mechanistic modeling can facilitate disclosing underlying tumor mechanisms and lead to identification of physical factors affecting proliferation and invasive behavior. Current mathematical models are often formulated at the tissue or organ scale with the scope of a direct clinical usefulness. Consequently, these approaches remain empirical and do not allow gaining insight into the tumor properties at the scale of small cell aggregates. Here, experimental and numerical studies of the dynamics of tumor aggregates are performed to propose a physics-based mathematical model as a general framework to investigate tumor microenvironment. The quantitative data extracted from the cellular capsule technology microfluidic experiments allow a thorough quantitative comparison with in silico experiments. This dual approach demonstrates the relative impact of oxygen and external mechanical forces during the time course of tumor model progression.

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Hydrogen desorption in SiGe films: A diffusion limited process

Applied Physics Letters ◽

10.1063/1.118429 ◽

1997 ◽

Vol 70 (24) ◽

pp. 3287-3289 ◽

Cited By ~ 4

Author(s):

J. Vizoso ◽

F. Martín ◽

J. Suñé ◽

M. Nafría

Keyword(s):

Hydrogen Desorption ◽

Diffusion Limited ◽

Limited Process

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Effect of age on induction of hepatic phosphoenolpyruvate carboxykinase by fasting

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1994.267.2.g195 ◽

1994 ◽

Vol 267 (2) ◽

pp. G195-G200 ◽

Cited By ~ 3

Author(s):

H. Van Remmen ◽

W. F. Ward

Keyword(s):

G Protein ◽

Time Course ◽

Phosphoenolpyruvate Carboxykinase ◽

Age Groups ◽

Fischer 344 Rats ◽

Fischer 344 ◽

Fasting And Refeeding ◽

Old Rats ◽

Rate Limiting ◽

Effect Of Age

This study examines the effect of age on the induction of the rate-limiting enzyme in gluconeogenesis, phosphoenolpyruvate carboxykinase (PEPCK), in response to fasting and refeeding in male Fischer 344 rats aged 3-18 mo. The rats were fasted for 30 h to increase the activity of PEPCK and subsequently were refed for 24 h to lower activity toward basal levels. PEPCK activity increased 2.2-fold in the 3-mo-old rats and 2.3-fold in the 18-mo-old rats during the 30-h fast. Therefore PEPCK induction during the 30-h fast was not altered with age. Similarly, refeeding resulted in a significant decrease in PEPCK activity at all ages. After the 24-h refeeding period, the rats were fasted a second time, and the time course of induction from the basal refed level was measured. In the young rats (6 mo), the activity of PEPCK increased rapidly from 18.12 +/- 1.61 to 42.66 +/- 5.94 U/g protein (P < 0.01) within 8 h of fasting. However, in the 18-mo-old rats, the initiation of the induction of PEPCK activity was delayed, and, after 12 h, PEPCK activity had increased from 17.34 +/- 1.34 to only 32.50 +/- 3.21 U/g protein (P < 0.01). Furthermore, the rate of induction appears to be decreased in the older animals. The activity after 24 h of fasting was equivalent in all four age groups (ranging from 44.72 +/- 5.38 at 3 mo to 40.18 +/- 5.42 U/g protein at 18 mo).(ABSTRACT TRUNCATED AT 250 WORDS)

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Synchronized Infection of Cell Cultures by Magnetically Controlled Virus

Journal of Virology ◽

10.1128/jvi.79.1.622-625.2005 ◽

2005 ◽

Vol 79 (1) ◽

pp. 622-625 ◽

Cited By ~ 37

Author(s):

Hillel Haim ◽

Israel Steiner ◽

Amos Panet

Keyword(s):

Adsorption Process ◽

Diffusion Rate ◽

Cell Attachment ◽

Diffusion Limited ◽

Rate Limiting Step ◽

Immunodeficiency Virus ◽

Rate Limiting ◽

And Diffusion ◽

Entry Mechanism

ABSTRACT To override the diffusion-limited adsorption step of viral infection, we magnetically synchronized cell attachment. Human immunodeficiency virus type 1-based lentivirus preparations were rendered magnetically reactive by association with magnetite nanoparticles, 50 nm in diameter. Application of a magnetic field resulted in immediate redistribution of the viral inoculum to the cell-associated state and completion of the productive adsorption process within 1 min. Independent of adsorption time, viral concentration, and diffusion rate, infection subsequently progressed by the receptor-mediated entry mechanism. Synchronization of this rate-limiting step of infection may now be applied to analyze isolated events in the viral replication sequence.

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Effect of a-SiC:H Film Composition on the Performance of Large Area Optical Sensors

MRS Proceedings ◽

10.1557/proc-685-d5.24.1 ◽

2001 ◽

Vol 685 ◽

Author(s):

P. Louro ◽

Yu. Vygranenko ◽

M. Fernandes ◽

M. Vieira ◽

M. Schubert

Keyword(s):

Optical Sensors ◽

Carrier Transport ◽

Energy Band Diagram ◽

Large Area ◽

Conduction Band Offset ◽

Sensor Performance ◽

Diffusion Limited ◽

Current Voltage ◽

Capacitance Voltage ◽

Limited Process

AbstractA series of large area single layers and heterojunction cells in the assembly glass/ZnO:Al/p (SixC1-x:H)/i (Si:H)/n (SixC1-x:H)/Al (0<x<1) were produced by PE-CVD at low temperature. Junction properties, carrier transport and photogeneration are investigated from dark and illuminated current-voltage and capacitance-voltage characteristics. For the heterojunction cells Atypical J-V characteristics under different illumination conditions are observed leading to poor fill factors. High serial resistances around 106 Ω are also measured. These experimental results were used as a basis for the numerical simulation of the energy band diagram, and the electrical field distribution of the whole structures. Further comparison with the sensor performance gave satisfactory agreement.Results show that the conduction band offset is the most limiting parameter for the optimal collection of the photogenerated carriers. As the optical gap increases and the conductivity of the doped layers decreases, the transport mechanism changes from a drift to a diffusion-limited process.

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Cell density is determined by a diffusion-limited process

Nature ◽

10.1038/278283b0 ◽

1979 ◽

Vol 278 (5701) ◽

pp. 283-284 ◽

Cited By ~ 7

Author(s):

ROBERT W. HOLLEY ◽

JULIA H. BALDWIN

Keyword(s):

Cell Density ◽

Diffusion Limited ◽

Limited Process

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Growth dynamics of cyclomaltodextrin glucanotransferase producing Bacillus circulans var. alkalophilus

Canadian Journal of Microbiology ◽

10.1139/m90-031 ◽

1990 ◽

Vol 36 (3) ◽

pp. 176-182 ◽

Cited By ~ 14

Author(s):

Mauri J. Mäkelä ◽

Sari K. Paavilainen ◽

Timo K. Korpela

Keyword(s):

Time Course ◽

Growth Parameters ◽

Growth Dynamics ◽

Point Of View ◽

Bacillus Circulans ◽

Amylolytic Enzyme ◽

Bulk Growth ◽

Atcc Strain ◽

Total Carbohydrates ◽

Cyclomaltodextrin Glucanotransferase

The time course of the growth of cyclomaltodextrin glucanotransferase (EC 2.4.1.19; CGTase) producing Bacillus circulans var. alkalophilus (ATCC 21783) was studied using shaking-flask cultivations. The growth curve was diauxic and during the initial phase the pH decreased sharply by 1.3–1.5 units. Most of the total carbohydrates disappeared prior to the bulk growth, which corresponded to a transient peak of amylolytic enzyme activity and of reducing sugars followed by acid production. During active cell growth the pH recovered by about 0.5 units and 65% of the final CGTase appeared in the medium. Another 20% was produced during the stationary phase and 15% was produced in the death phase. The growth dynamics of two randomly selected alkalophilic Bacillus strains (ATCC 27647 and 27557) were compared with those of ATCC-strain 21783. The reference strains showed related growth behavior with the exception that the timing and magnitudes of the changes in the growth parameters measured were different. The effects of carbon source (starch), nitrogen source (yeast extract plus Bacto-pantone), sodium carbonate, and temperature were studied from the point of view of CGTase production. Key words: cyclomaltodextrin glucanotransferase; alkalophilic bacilli; cyclodextrins.

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