Shear stress effects on cell growth and L-DOPA production by suspension culture of Stizolobium hassjoo cells in an agitated bioreactor

2000 ◽  
Vol 22 (1) ◽  
pp. 5-12 ◽  
Author(s):  
S. Y. Chen ◽  
S. Y. Huang
Keyword(s):  
Shear Stress ◽  
Cell Growth ◽  
Suspension Culture ◽  
Stress Effects

scholarly journals Induction of Stem Cell Like Cells from Mouse Embryonic Fibroblast by Short-Term Shear Stress and Vitamin C

2021 ◽  
Vol 11 (4) ◽  
pp. 1941
Author(s):  
Seungmin Yeom ◽  
Myung Chul Lee ◽  
Shambhavi Pandey ◽  
Jaewoon Lim ◽  
Sangbae Park ◽  
...  
Keyword(s):  
Stem Cells ◽  
Shear Stress ◽  
Stem Cell ◽  
Vitamin C ◽  
Suspension Culture ◽  
Small Molecules ◽  
Tumor Development ◽  
Embryonic Stem ◽  
Short Term ◽  
External Stimuli

Induced pluripotent stem cells (iPSCs) are a good medicine source because of their potential to differentiate into various tissues or cells. However, traditionally, iPSCs made by specific transgenes and virus vectors are not appropriate for clinical use because of safety concerns and risk of tumor development. The goal of this research was to develop an alternative method for reprogramming, using small molecules and external stimuli. Two groups were established: short-term shear stress (STSS) under suspension culture and a combination of short-term shear stress and vitamin C (SSVC) under suspension culture. For STSS, the pipetting was carried out for cells twice per day for 2 min for 14 days in the embryonic stem cell (ES) medium. In the case of SSVC, the procedure was the same as for STSS however, its ES medium included 10 µM of vitamin C. After 14 days, all spheroids were picked and checked for pluripotency by ALP (alkaline phosphatase) assay and immunocytochemistry. Both groups partially showed the characteristics of stem cells but data demonstrated that the spheroids under shear stress and vitamin C had improved stem cell-like properties. This research showed the possibility of external stimuli and small molecules to reprogram the somatic cells without the use of transgenes.

scholarly journals Studying dynamic stress effects on the behaviour of THP-1 cells by microfluidic channels

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Semra Zuhal Birol ◽  
Rana Fucucuoglu ◽  
Sertac Cadirci ◽  
Ayca Sayi-Yazgan ◽  
Levent Trabzon
Keyword(s):  
Endothelial Cells ◽  
Shear Stress ◽  
Vascular System ◽  
Circulatory System ◽  
Disease Process ◽  
Microfluidic Channels ◽  
Shear Stresses ◽  
Stress Effects ◽  
Adhesion Behavior ◽  
Cycling System

AbstractAtherosclerosis is a long-term disease process of the vascular system that is characterized by the formation of atherosclerotic plaques, which are inflammatory regions on medium and large-sized arteries. There are many factors contributing to plaque formation, such as changes in shear stress levels, rupture of endothelial cells, accumulation of lipids, and recruitment of leukocytes. Shear stress is one of the main factors that regulates the homeostasis of the circulatory system; therefore, sudden and chronic changes in shear stress may cause severe pathological conditions. In this study, microfluidic channels with cavitations were designed to mimic the shape of the atherosclerotic blood vessel, where the shear stress and pressure difference depend on design of the microchannels. Changes in the inflammatory-related molecules ICAM-1 and IL-8 were investigated in THP-1 cells in response to applied shear stresses in an continuous cycling system through microfluidic channels with periodic cavitations. ICAM-1 mRNA expression and IL-8 release were analyzed by qRT-PCR and ELISA, respectively. Additionally, the adhesion behavior of sheared THP-1 cells to endothelial cells was examined by fluorescence microscopy. The results showed that 15 Pa shear stress significantly increases expression of ICAM-1 gene and IL-8 release in THP-1 cells, whereas it decreases the adhesion between THP-1 cells and endothelial cells.

scholarly journals Numerical Study of Fluid Dynamics in Suspension Culture of iPS Cells

2019 ◽  
Vol 17 (1) ◽  
pp. 73 ◽  
Author(s):  
Masaki Yano ◽  
Takuya Yamamoto ◽  
Yasunori Okano ◽  
Toshiyuki Kanamori ◽  
Mashiro Kino–oka
Keyword(s):  
Shear Stress ◽  
Suspension Culture ◽  
Numerical Study ◽  
Maximum Shear Stress ◽  
Ips Cells ◽  
Stirred Tanks ◽  
Average Shear Stress ◽  
Average Shear ◽  
Orbital Shaking ◽  
Induced Pluripotent

In a suspension culture of iPS cells, the shear stress generated during mixing is expected to promote differentiation of induced pluripotent stem (iPS) cells. The stress on the cells can be controlled by rotational rate and shape of impeller. However, it is difficult to optimize these operative parameters by experiments. Therefore, we have developed a numerical model to obtain the average and the maximum shear stress in two kinds of stirred tanks and an orbital shaking cylindrical container. The present results showed that the shear stress strongly depended on the type of mixing and lesser extent on the shape of the impeller. The average shear stress is larger in the shaking mode than that in the stirring mode. In contrast, the maximum shear stress is much smaller in the shaking than the stirring. These results suggest that stirring and shaking should be selectively used depending on the application

scholarly journals Soil irrigation frequencies, compaction, air porosity and shear stress effects on soybean root development

2015 ◽  
Vol 25 (1) ◽  
pp. 22-30 ◽  
Author(s):  
G. A. Hossne ◽  
J. Méndez ◽  
M. Trujillo ◽  
F. Parra
Keyword(s):  
Shear Stress ◽  
Root Development ◽  
Soybean Root ◽  
Stress Effects ◽  
Soil Irrigation

Temporal Control of Osteoblast Cell Growth and Behavior Dictated by Nanotopography and Shear Stress

2016 ◽  
Vol 15 (7) ◽  
pp. 704-712 ◽  
Author(s):  
Udesh Dhawan ◽  
Hsu-An Pan ◽  
Ying Hao Chu ◽  
Guewha S. Huang ◽  
Po Chun Chen ◽  
...  
Keyword(s):  
Shear Stress ◽  
Cell Growth ◽  
Osteoblast Cell ◽  
Temporal Control ◽  
And Behavior

Time and Stress Effects in the Behavior of Rubber at Low Temperature

1950 ◽  
Vol 23 (1) ◽  
pp. 54-66 ◽  
Author(s):  
J. R. Beatty ◽  
J. M. Davies
Keyword(s):  
Shear Stress ◽  
Low Temperature ◽  
Natural Rubber ◽  
Applied Stress ◽  
Dynamic Modulus ◽  
Rate Of Change ◽  
Rate Process ◽  
X Ray ◽  
Stress Effects ◽  
Rubberlike Materials

Abstract The stiffening of rubberlike materials at low temperature involves several different phenomena, sometimes with their effects superimposed. One of these is crystallization. This is a rate process which is generally very fast at high stresses and very slow at zero stress. In these experiments at temperatures near −25° C and under a shear stress of about 148 lb. per sq. in. the dynamic modulus of the rubber increased at a rate convenient to study. Correlation with x-ray data showed that crystallization was very likely responsible for the increase in stiffness. The rate of change of stiffness increased rapidly with increase in applied stress, and there was no optimum rate at −25° C, as has been found for unstressed rubber. The degree of vulcanization influenced the rate of change, tighter cures giving smaller changes. Neoprene-FR, GR-S, and polybutadiene, which ordinarily show little evidence of crystallization, showed very definite, but small increases in stiffness. Mixing GR-S with natural rubber seems to limit the crystallization of the natural rubber rather effectively, but apparently Neoprene-FR does not mix intimately enough with natural rubber to affect the crystallization of the latter appreciably.

Sign in / Sign up

Export Citation Format

Share Document