Improved in-vitro biocompatibility of LZ91 Mg–Li alloy by formation of nanostructured Ti coating through surface mechanical nano-alloying treatment

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jian Sun ◽  
Xiangcun Zhu ◽  
Zhuo Chen ◽  
Yi Li ◽  
Yonghong Zhang
Keyword(s):  
Grain Size ◽  
Surface Hardness ◽  
Coated Sample ◽  
Untreated Sample ◽  
In Vitro Biocompatibility ◽  
Cell Proliferation And Differentiation ◽  
Average Grain Size ◽  
Proliferation And Differentiation ◽  
Alloy Microstructure

Abstract Surface mechanical nano-alloying treatment (SMNAT) was employed to fabricate a nanostructured Ti coating on LZ91 Mg–Li alloy. Microstructure, surface hardness and in-vitro biocompatibility of the Ti-coated sample were investigated in comparison with those of an untreated sample. Experimental results showed that a nanostructured Ti coating with a thickness of 35 to 60 μm was formed after SMNAT for 2 h. The average grain size in the top surface of the Ti coating was about 30 nm. The surface of the Ti coating is rougher than that of the untreated LZ91 sample, in which the values of Ra, Rq and Rz were 7.83, 9.57 and 14.85 μm, respectively. The hardness of the Ti coating top surface was about 483 HV. Cell proliferation and differentiation on Ti coated samples were enhanced relative to those on the untreated samples.

scholarly journals Biocompatibility Characteristics of Titanium Coated with Multi Walled Carbon Nanotubes—Hydroxyapatite Nanocomposites

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 224 ◽  
Author(s):  
Jung-Eun Park ◽  
Yong-Seok Jang ◽  
Tae-Sung Bae ◽  
Min-Ho Lee
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Sol Gel ◽  
Pure Titanium ◽  
Cell Proliferation And Differentiation ◽  
Transmission Electron ◽  
Proliferation And Differentiation ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.

scholarly journals Mechanics of the cellular microenvironment as perceived by cells in vivo

2021 ◽  
Author(s):  
Alessandro Mongera ◽  
Marie Pochitaloff ◽  
Hannah J. Gustafson ◽  
Georgina A. Stooke-Vaughan ◽  
Payam Rowghanian ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Mechanical Parameters ◽  
Cellular Microenvironment ◽  
Stem Cell Maintenance ◽  
Quantitative Studies ◽  
Cell Proliferation And Differentiation ◽  
3D Microenvironment ◽  
Proliferation And Differentiation

Tissue morphogenesis and repair, as well as organ homeostasis, require cells to constantly monitor their 3D microenvironment and adapt their behaviors in response to local biochemical and mechanical cues1-6. In vitro studies have shown that substrate stiffness and stress relaxation are important mechanical parameters in the control of cell proliferation and differentiation, stem cell maintenance, cell migration 7-11, as well as tumor progression and metastasis12,13. Yet, the mechanical parameters of the microenvironment that cells perceive in vivo, within 3D tissues, remain unknown. In complex materials with strain- and time-dependent material properties, the perceived mechanical parameters depend both on the strain and timescales at which the material is mechanically probed14. Here, we quantify in vivo and in situ the mechanics of the cellular microenvironment that cells probe during vertebrate presomitic mesoderm (PSM) specification. By analyzing the magnitude and dynamics of endogenous, cell-generated strains, we show that individual cells preferentially probe the stiffness associated with deformations of the supracellular, foam-like tissue architecture. We reveal how stress relaxation leads to a perceived microenvironment stiffness that decreases over time, with cells probing the softest regime. While stress relaxation timescales are spatially uniform in the tissue, most mechanical parameters, including those probed by cells, vary along the anteroposterior axis, as mesodermal progenitors commit to different lineages. Understanding the mechanical parameters that cells probe in their native 3D environment is important for quantitative studies of mechanosensation in vivo2-4,6,15 and can help design scaffolds for tissue engineering applications16-18.

scholarly journals Critical role of integrin CD11c in splenic dendritic cell capture of missing-self CD47 cells to induce adaptive immunity

2018 ◽  
Vol 115 (26) ◽  
pp. 6786-6791 ◽  
Author(s):  
Jiaxi Wu ◽  
Huaizhu Wu ◽  
Jinping An ◽  
Christie M. Ballantyne ◽  
Jason G. Cyster
Keyword(s):  
Critical Role ◽  
T Cell Proliferation ◽  
Cell Capture ◽  
Antigen Uptake ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Missing Self

CD11c, also known as integrin alpha X, is the most widely used defining marker for dendritic cells (DCs). CD11c can bind complement iC3b and mediate phagocytosis in vitro, for which it is also referred to as complement receptor 4. However, the functions of this prominent marker protein in DCs, especially in vivo, remain poorly defined. Here, in the process of studying DC activation and immune responses induced by cells lacking self-CD47, we found that DC capture of CD47-deficient cells and DC activation was dependent on the integrin-signaling adaptor Talin1. Specifically, CD11c and its partner Itgb2 were required for DC capture of CD47-deficient cells. CD11b was not necessary for this process but could partially compensate in the absence of CD11c. Mice with DCs lacking Talin1, Itgb2, or CD11c were defective in supporting T-cell proliferation and differentiation induced by CD47-deficient cell associated antigen. These findings establish a critical role for CD11c in DC antigen uptake and activation in vivo. They may also contribute to understanding the functional mechanism of CD47-blockade therapies.

scholarly journals Effects of RAC1 on Proliferation of Hen Ovarian Prehierarchical Follicle Granulosa Cells

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1589
Author(s):  
Thobela Louis Tyasi ◽  
Xue Sun ◽  
Xuesong Shan ◽  
Simushi Liswaniso ◽  
Ignatius Musenge Chimbaka ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Biological Effects ◽  
Expression Levels ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Mrna And Protein Expression ◽  
Chicken Ovary ◽  
New Evidence ◽  
Follicle Selection

RAC1 belongs to the small G protein Rho subfamily and is implicated in regulating gene expression, cell proliferation and differentiation in mammals and humans; nevertheless, the function of RAC1 in growth and development of hen ovarian follicles is still unclear. This study sought to understand the biological effects of RAC1 on granulosa cell (GC) proliferation and differentiation of hen ovarian prehierarchical follicles. Firstly, our results showed expression levels of RAC1 mRNA in the follicles with diameters of 7.0–8.0 mm, 6.0–6.9 mm and 1.0–3.9 mm were greater than other follicles (p < 0.05). The RAC1 protein was mainly expressed in oocyte and its around GCs and stromal tissues of the prehierarchical follicles by immunohistochemistry. Further investigation revealed the RAC1 gene remarkably enhanced the mRNA and protein expression levels of FSHR (a marker of follicle selection), CCND2 (a marker of cell-cycle progression and GC differentiation), PCNA (a marker of GC proliferation), StAR and CYP11A1 (markers of GC differentiation and steroidogenesis) (p < 0.05). Furthermore, our data demonstrated siRNA interference of RAC1 significantly reduced GC proliferation (p < 0.05), while RAC1 gene overexpression enhanced GC proliferation in vitro (p < 0.05). Collectively, this study provided new evidence that the biological effects of RAC1 on GC proliferation, differentiation and steroidogenesis of chicken ovary follicles.

Microstructure Prediction by Finite Element Analysis during Hot Rolling of Magnesium Alloy Sheets

2015 ◽  
Vol 661 ◽  
pp. 105-112
Author(s):  
Yeong Maw Hwang ◽  
Tso Lun Yeh
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Optimal Conditions ◽  
Compression Tests ◽  
Element Analysis ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Microstructure Prediction ◽  
Alloy Microstructure ◽  
The Relationship

Material’s plastic deformation by hot forming processes can be used to make the materials generate dynamic recrystallization (DRX) and fine grains and accordingly products with more excellent mechanical properties, such as higher strength and larger elongation can be obtained. In this study, compression tests and water quenching are conducted to obtain the flow stress of the materials and the grain size after DRX. Through the regression analysis, prediction equations for the magnesium alloy microstructure were established. Simulations with different rolling parameters are conducted to find out the relationship between the DRX fractions or grain sizes of the rolled products and the rolling parameters. The simulation results show that rolling temperature of 400°C and thickness reduction of 50% are the optimal conditions. An average grain size of 0.204μm-0.206μm in the microstructure is obtained and the strength and formability of ZK60 magnesium alloys can be improved.

scholarly journals The nerve growth factor-responsive PC12 cell line does not express the Myc dimerization partner Max.

1995 ◽  
Vol 15 (7) ◽  
pp. 3470-3478 ◽  
Author(s):  
R Hopewell ◽  
E B Ziff
Keyword(s):  
Cell Line ◽  
Pc12 Cell ◽  
Tumor Cell Line ◽  
Pc12 Cell Line ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
E Box ◽  
Associated Proteins ◽  
And Control

Heterodimerization of Max with the nuclear oncoprotein Myc and the differentiation-associated proteins Mad and Mxi1 enables these factors to bind E-box sites in DNA and control genes implicated in cell proliferation and differentiation. We show that in the PC12 pheochromocytoma tumor cell line, functional Max protein is not expressed because of the synthesis of a mutant max transcript. This transcript encodes a protein incapable of homo- or heterodimerization. Furthermore, the mutant Max protein, unlike wild-type Max, is incapable of repressing transcription from an E-box element. Synthesis of mutant max transcripts appears to be due to a homozygous chromosomal alteration within the max gene. Reintroduction of max into PC12 cells results in repression of E-box-dependent transcription and a reduction in growth rate, which may explain the loss of Max expression either during the growth of the pheochromocytoma or in subsequent passage of the PC12 cell line in vitro. Finally, the ability of these cells to divide, differentiate, and apoptose in the absence of Max demonstrates for the first time that these processes can occur via Max- and possibly Myc-independent mechanisms.

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