scholarly journals Liquid Rise in Uniform Screens under Normal Gravity and Microgravity Conditions

2019 ◽  
Author(s):  
Weng Ning ◽  
Qinggong Wang ◽  
Wei Yao ◽  
Rong Ma ◽  
Yuying Wang ◽  
...  
Keyword(s):  
Normal Gravity ◽  
Microgravity Conditions

Reaction and phase separation mechanisms during synthesis of alloys by thermite type combustion reactions

2003 ◽  
Vol 18 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Cheryl Lau ◽  
Alexander S. Mukasyan ◽  
Arvind Varma
Keyword(s):  
Phase Separation ◽  
Normal Gravity ◽  
Metal Alloy ◽  
Fundamental Study ◽  
Separation Mechanisms ◽  
Segregation Process ◽  
Microgravity Conditions ◽  
Gravity Driven ◽  
Orthopedic Applications

Combustion of the thermite system is a promising approach for synthesis of alloys (e.g., Co-based) that are widely used in orthopedic applications. This process typically involves formation of two liquids (oxide and metal alloy), followed by their phase separation. The latter is generally believed to be controlled solely by gravity-driven buoyancy. To verify this hypothesis, a fundamental study of phase separation during alloy synthesis was conducted in both normal gravity and microgravity conditions. It was shown that a non-gravity-driven mechanism primarily controls the segregation process. Quenching experiments identified the reaction and phase separation mechanisms in the investigated systems.

scholarly journals Transcriptomic analysis of DNA damage response in zebrafish embryos under simulated microgravity

2021 ◽  
Author(s):  
Subhrajit Barua ◽  
Elia Brodsky ◽  
Harpreet Kaur ◽  
Aleksei Komissarov
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Simulated Microgravity ◽  
Normal Gravity ◽  
Enrichment Analysis ◽  
Differentially Expressed ◽  
Pathway Enrichment Analysis ◽  
Zebrafish Embryos ◽  
Damage Response ◽  
Microgravity Conditions

Objective: The objective of this study is to study the transcriptome of zebrafish embryos subjected to simulated microgravity and explore affected biological pathways, especially DNA damage response (DDR). The research question is whether simulated microgravity can have an impact on the basic biology of cell division, DNA repair, inflammation, and other vital cellular mechanisms. To validate that such experiments can yield relevant insights into human health and microgravity, we will correlate the found effects of simulated microgravity on zebrafish embryos with the reported effects of spaceflight on astronauts. Methods: 12 wild-type zebrafish embryos of both sexes, and of 3 to 12 months of age were microinjected with 2 nL (1 μg/μL) poly I:C or mock PBS buffer (0.5% phenol red, 240 mM KCl, and 40 mM HEPES at pH 7.4) using a microinjector followed by subjecting them immediately to the simulated microgravity conditions generated by RCCS or the normal gravity conditions in a cell culture dish. RNA-SEQ was performed on the samples according to the standard protocol. Raw gene counts data were obtained from the public domain (NASA Gene Labs) and subjected to further downstream analyses. Differential gene expression was performed using DESeq2. The results were annotated using pathway enrichment analysis (GSEA) on the KEGG pathway database and compared with the result of the NASA twin study. Result: Similar to previously published analysis, we found that a significant number of genes were differentially expressed under simulated microgravity conditions. We identified a total of 7542 genes out of 16532 when comparing expression between the groups: simulated microgravity and normal gravity (padj. value <0.05, log2 fold change in between -2 and 2). Out of these genes, 4504 were found to be up-regulated while 3038 were down-regulated compared to controls. Pathway enrichment analysis revealed that simulated microgravity has an effect on vital basic biological processes like DNA repair, peptide transport, and metabolism. Various other well-known signalling pathways like Notch signalling, wnt signalling, and p53 signalling were also significantly altered. These pathways are known to play an important role in DDR. To explore if the same pathways were also altered in humans, we explored the NASA twin study data and found that DDR was also significantly affected in the astronaut but due to ionizing radiation. Upon further investigation, we found that 62 genes belonging to the DDR pathway were mutually differentially expressed in Scott Kelly and the zebrafish embryos. However, there were 29 significantly differentially expressed genes belonging to the DDR pathway in zebrafish embryos that were not found to be differentially expressed in Scott Kelly. Out of these 29 genes, 14 were specific to zebrafish. Upon further investigation, we found that the DDR pathway is affected differently in simulated microgravity as compared to ionizing radiation. Conclusion: Simulated microgravity alters numerous biological pathways in zebrafish embryos, including DDR. But the nature of it is different from that of real spaceflight induced DDR. These observations should be investigated further to actually understand the nature of DNA damage response during spaceflights.

Modeling of Phosphate Ion Transfer to the Surface of Osteoblasts under Normal Gravity and Simulated Microgravity Conditions

2004 ◽  
Vol 1027 (1) ◽  
pp. 85-98 ◽  
Author(s):  
KARTHIK MUKUNDAKRISHNAN ◽  
PORTONOVO S. AYYASWAMY ◽  
MAKARAND RISBUD ◽  
HOWARD H. HU ◽  
IRVING M. SHAPIRO
Keyword(s):  
Simulated Microgravity ◽  
Normal Gravity ◽  
Ion Transfer ◽  
Phosphate Ion ◽  
Microgravity Conditions

scholarly journals Mechanism for enhancing the growth of mung bean seedlings under simulated microgravity

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Shusaku Nakajima ◽  
Masayasu Nagata ◽  
Akifumi Ikehata
Keyword(s):  
Mung Bean ◽  
Gravitational Force ◽  
Simulated Microgravity ◽  
Normal Gravity ◽  
Near Infrared ◽  
Amylase Activity ◽  
Infrared Image ◽  
Water Evaporation ◽  
Fresh Weight ◽  
Microgravity Conditions

AbstractTo elucidate a mechanism for enhancing mung bean seedlings’ growth under microgravity conditions, we measured growth, gene expression, and enzyme activity under clinorotation (20 rpm), and compared data obtained to those grown under normal gravity conditions (control). An increase in fresh weight, water content, and lengths were observed in the clinostat seedlings, compared to those of the control seedlings. Real-time PCR showed that aquaporin expression and the amylase gene were upregulated under clinorotation. Additionally, seedlings under clinorotation exhibited a significantly higher amylase activity. Near-infrared image showed that there was no restriction of water evaporation from the seedlings under clinorotation. Therefore, these results indicate that simulated microgravity could induce water uptake, resulting in enhanced amylase activity and seedling growth. Upregulated aquaporin expression could be the first trigger for enhanced growth under clinorotation. We speculated that the seedlings under clinorotation do not use energy against gravitational force and consumed surplus energy for enhanced growth.

scholarly journals Synthesis and Characteristics of CdS Nanoparticles in Normal (1 g) and Simulated Microgravity (SMG)

2020 ◽  
Vol 22 (1) ◽  
pp. 7
Author(s):  
P. S. Shinde ◽  
L. D. Adhav ◽  
R. M. Pise ◽  
S. S. Jagtap
Keyword(s):  
Simulated Microgravity ◽  
Normal Gravity ◽  
Control Sample ◽  
Cadmium Sulphide ◽  
Cds Nanoparticles ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Random Positioning Machine ◽  
Cds Nanoparticle ◽  
Microgravity Conditions

In the present investigation, the cadmium sulphide (CdS) nanoparticles are synthesized in the normal gravity i.e. 1 g (called as control) and in simulated microgravity (called as SMG). The SMG was created by using an instrument called Random Positioning Machine (RPM). Cadmium sulfide nanoparticles were synthesized by using standard chemical method under normal gravity (1 g) and simulated microgravity conditions. The synthesized CdS nanoparticles were characterized by Ultraviolet Visible spectroscopy, Fourier Transform Infrared Ray spectroscopy (FTIR), X-ray diffraction (XRD). The UV-visible absorption spectrum of CdS nanoparticle solution showed a distinct absorption peak at 472.19 nm in control and 458.26 nm in SMG. The band gap calculated from the absorption edge for microgravity sample was 2.71 eV and for control sample was 2.63 eV.  The crystalline size of CdS nanoparticles synthesised in control and Micro-g was determined by XRD. Obtained results showed smaller the particle size in microgravity sample (10.78 nm) as compared to control sample (13.89 nm).

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