Foaming and thermal characteristics of bio-based polylactic acid–thermoplastic polyurethane blends

2018 ◽  
Vol 54 (6) ◽  
pp. 931-955 ◽  
Author(s):  
Mohsen Barmouz ◽  
Amir Hossein Behravesh
Keyword(s):  
Polylactic Acid ◽  
High Cell Density ◽  
Thermoplastic Polyurethane ◽  
Research Work ◽  
Thermal Characteristics ◽  
High Cell ◽  
Foam Expansion ◽  
Foaming Process ◽  
Cell Densities

This paper reports a research work on characterization of foamed biocompatible polylactic acid–thermoplastic polyurethane blends in terms of microstructural, thermal, and physical properties. The brittleness of the polylactic acid is compensated via blending with an elastoplastic phase of thermoplastic polyurethane. A range of low bulk density foam with a high cell density was produced in a solid state foaming process. Addition of thermoplastic polyurethane phase acted against the cell growth and thus foam expansion, apparently due to its inherent lower storage modulus, which weakens the polymer matrix and leads to gas escape phenomenon. Evaluation of thermal properties showed a tangible effect of blending and foaming process on crystallization of the specimens, which confirmed that the sensitivity of polylactic acid’s crystallinity to CO2 gas saturation was reduced as a result of thermoplastic polyurethane addition. Measurement of cell diameters and cell densities of the foamed samples demonstrated formation of the fine closed cells structure as a result of suitable foaming parameters that were able to deal with stiffness and strength of the polymeric matrix.

Microstructured scaffolds for liver tissue cultures of high cell density: Morphological and biochemical characterization of tissue aggregates

2005 ◽  
Vol 95 (2) ◽  
pp. 243-255 ◽  
Author(s):  
Erik Eschbach ◽  
Shyam S. Chatterjee ◽  
Michael Nöldner ◽  
Eric Gottwald ◽  
Hermann Dertinger ◽  
...  
Keyword(s):  
Cell Density ◽  
Liver Tissue ◽  
Biochemical Characterization ◽  
High Cell Density ◽  
Tissue Cultures ◽  
High Cell

Characterization of periplasmicEscherichia coli protein expression at high cell densities

1999 ◽  
Vol 20 (4-5) ◽  
pp. 790-797 ◽  
Author(s):  
Bo Franzén ◽  
Susanne Becker ◽  
Riitta Mikkola ◽  
Kenneth Tidblad ◽  
Agneta Tjernberg ◽  
...  
Keyword(s):  
Protein Expression ◽  
High Cell ◽  
Cell Densities

scholarly journals 3D bioprinting of high cell-density heterogeneous tissue models through spheroid fusion within self-healing hydrogels

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Andrew C. Daly ◽  
Matthew D. Davidson ◽  
Jason A. Burdick
Keyword(s):  
Cell Density ◽  
Spatial Organization ◽  
High Cell Density ◽  
Self Healing ◽  
High Cell ◽  
Cellular Models ◽  
Functional Features ◽  
Cell Densities ◽  
Tissue Models

AbstractCellular models are needed to study human development and disease in vitro, and to screen drugs for toxicity and efficacy. Current approaches are limited in the engineering of functional tissue models with requisite cell densities and heterogeneity to appropriately model cell and tissue behaviors. Here, we develop a bioprinting approach to transfer spheroids into self-healing support hydrogels at high resolution, which enables their patterning and fusion into high-cell density microtissues of prescribed spatial organization. As an example application, we bioprint induced pluripotent stem cell-derived cardiac microtissue models with spatially controlled cardiomyocyte and fibroblast cell ratios to replicate the structural and functional features of scarred cardiac tissue that arise following myocardial infarction, including reduced contractility and irregular electrical activity. The bioprinted in vitro model is combined with functional readouts to probe how various pro-regenerative microRNA treatment regimes influence tissue regeneration and recovery of function as a result of cardiomyocyte proliferation. This method is useful for a range of biomedical applications, including the development of precision models to mimic diseases and the screening of drugs, particularly where high cell densities and heterogeneity are important.

scholarly journals Morphometric characterization of Dinophysis acuminata/D. sacculus complex in Guanabara Bay, Brazil

2019 ◽  
Vol 19 (3) ◽  
Author(s):  
José Juan Barrera-Alba ◽  
Fernanda Reinhardt Piedras ◽  
Carla Lucatelli Duarte ◽  
Raquel Neves Tavares Lopes ◽  
Gleyci Aparecida Oliveira Moser
Keyword(s):  
Present Note ◽  
Guanabara Bay ◽  
High Cell ◽  
Complex Species ◽  
Toxic Species ◽  
Production And Consumption ◽  
Dinophysis Acuminata ◽  
Cell Densities ◽  
Morphometric Characterization

Abstract: Most studies of Dinophysis acuminata in Brazil are for the southern region, where blooms are recurrent. In 2016, the presence of D. acuminata caused the first-ever production and consumption of species of mollusks commercial embargo from the state of Sao Paulo, Southeast Brazil. Potentially toxic species of Dinophysis have been reported in Guanabara Bay (GB) but only occasionally and in low densities. The present note is the first report of a high-density event (~105 cells L-1) of D. acuminata/D. sacculus complex in GB. D. acuminata/D. sacculus complex species were identified using scanning-electron and inverted-light microscopy. Most of the studied cells possessed a dorsally convex hyposomal plate and had dimensions typical of D. acuminata. However, the observed association with warmer and less saline estuarine waters would indicate that the species could be D. sacculus. Whatever the case, based on the high cell densities observed here, we recommend a continued monitoring for Dinophysis presence in GB.

Characterization of lycopene-overproducing E. coli strains in high cell density fermentations

2006 ◽  
Vol 72 (5) ◽  
pp. 968-974 ◽  
Author(s):  
Hal Alper ◽  
Kohei Miyaoku ◽  
Gregory Stephanopoulos
Keyword(s):  
Cell Density ◽  
High Cell Density ◽  
High Cell ◽  
E Coli

scholarly journals 3D bioprinting of high cell-density heterogeneous tissue models through spheroid fusion within self-healing hydrogels

2020 ◽  
Author(s):  
Andrew C. Daly ◽  
Matthew D. Davidson ◽  
Jason A. Burdick
Keyword(s):  
Cell Density ◽  
Spatial Organization ◽  
High Cell Density ◽  
Self Healing ◽  
High Cell ◽  
Cellular Models ◽  
Functional Features ◽  
Cell Densities ◽  
Tissue Models

AbstractCellular models are needed to study human development and disease in vitro, including the screening of drugs for toxicity and efficacy. However, current approaches are limited in the engineering of functional tissue models with requisite cell densities and heterogeneity to appropriately model cell and tissue behaviors. Here, we develop a new bioprinting approach to transfer spheroids into self-healing support hydrogels at high resolution, which enables their patterning and fusion into high-cell density microtissues of prescribed spatial organization. As an example application, we bioprint induced pluripotent stem cell-derived cardiac microtissue models with spatially controlled cardiomyocyte and fibroblast cell ratios to replicate the structural and functional features of scarred cardiac tissue that arise following myocardial infarction, including reduced contractility and irregular electrical activity. The bioprinted in vitro model is combined with functional readouts to probe how various pro-regenerative microRNA treatment regimes influence tissue regeneration and recovery of function as a result of cardiomyocyte proliferation. This method is useful for a range of biomedical applications, including the development of precision models to mimic diseases and for the screening of drugs, particularly where high cell densities and heterogeneity are important.

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