نتایج جستجو برای: microgravity

تعداد نتایج: 3241  

2013
Carl W. Carruthers Jr Cory Gerdts Michael D. Johnson Paul Webb

The attenuation of sedimentation and convection in microgravity can sometimes decrease irregularities formed during macromolecular crystal growth. Current terrestrial protein crystal growth (PCG) capabilities are very different than those used during the Shuttle era and that are currently on the International Space Station (ISS). The focus of this experiment was to demonstrate the use of a comm...

2012
Richard L. Summers Weston Smith Ryan Gilbrech Jun Liao Benjamin C. Weed Sourav Patnaik

There is concern regarding the effects of microgravity exposure on cardiac function and loss of ventricular mass in astronauts. By Laplace’s law, the geometry of the ventricle is important in determining segmental wall stress and can induce alterations in myocardial mass. If microgravity exposure results in a variation in the ventricular radius of curvature, then we might also expect some cardi...

2016
Bryan J. Feger J. Will Thompson Laura G. Dubois Reddy P. Kommaddi Matthew W. Foster Rajashree Mishra Sudha K. Shenoy Yoichiro Shibata Yared H. Kidane M. Arthur Moseley Lisa S. Carnell Dawn E. Bowles

On Earth, biological systems have evolved in response to environmental stressors, interactions dictated by physical forces that include gravity. The absence of gravity is an extreme stressor and the impact of its absence on biological systems is ill-defined. Astronauts who have spent extended time under conditions of minimal gravity (microgravity) experience an array of biological alterations, ...

Journal: :FEMS microbiology letters 2014
Xingqun Cheng Xin Xu Jing Chen Xuedong Zhou Lei Cheng Mingyun Li Jiyao Li Renke Wang Wenxiang Jia Yu-Qing Li

Long-term spaceflights will eventually become an inevitable occurrence. Previous studies have indicated that oral infectious diseases, including dental caries, were more prevalent in astronauts due to the effect of microgravity. However, the impact of the space environment, especially the microgravity environment, on the virulence factors of Streptococcus mutans, a major caries-associated bacte...

Journal: :Soil Science Society of America journal. Soil Science Society of America 2005
Lakshmi N Reddi Ming Xiao Susan L Steinberg

Designing a reliable plant growth system for crop production in space requires the understanding of pore fluid distribution in porous media under microgravity. The objective of this experimental investigation, which was conducted aboard NASA KC-135 reduced gravity flight, is to study possible particle separation and the distribution of discontinuous wetting fluid in porous media under micrograv...

ژورنال: پژوهش در پزشکی 2018

Abstract Introduction: Physiology of reproduction is very complex and many factors influence on animal infertility.Today, researchers simulate weightlessness physiology  for investigation about  space biology. The best successful model for microgravity physiology simulation on the floor is in the rat hind-limb suspenion .The aim of this study is evaluation and comparision of  the effect of v...

Journal: :PloS one 2016
Basudev Chowdhury Arun Seetharam Zhiping Wang Yunlong Liu Amy C Lossie Jyothi Thimmapuram Joseph Irudayaraj

Cells alter their gene expression in response to exposure to various environmental changes. Epigenetic mechanisms such as DNA methylation are believed to regulate the alterations in gene expression patterns. In vitro and in vivo studies have documented changes in cellular proliferation, cytoskeletal remodeling, signal transduction, bone mineralization and immune deficiency under the influence o...

2012
Fei Shi Yong-Chun Wang Tian-Zhi Zhao Shu Zhang Ting-Yuan Du Chang-Bin Yang Ying-Hui Li Xi-Qing Sun

Endothelial cells are very sensitive to microgravity and the morphological and functional changes in endothelial cells are believed to be at the basis of weightlessness-induced cardiovascular deconditioning. It has been shown that the proliferation, migration, and morphological differentiation of endothelial cells play critical roles in angiogenesis. However, the influence of microgravity on th...

2016
Rajneesh Jha Qingling Wu Monalisa Singh Marcela K. Preininger Pengcheng Han Gouliang Ding Hee Cheol Cho Hanjoong Jo Kevin O. Maher Mary B. Wagner Chunhui Xu

Efficient generation of cardiomyocytes from human pluripotent stem cells is critical for their regenerative applications. Microgravity and 3D culture can profoundly modulate cell proliferation and survival. Here, we engineered microscale progenitor cardiac spheres from human pluripotent stem cells and exposed the spheres to simulated microgravity using a random positioning machine for 3 days du...

Journal: :Journal of cell science 1993
D A Schmitt P Ohlmann C Gachet J P Cazenave

Recent experiments have shown that the stimulation of animal cells in vitro by direct protein kinase C (PKC) activators is significantly reduced under microgravity (micro g). Platelets undergo protein phosphorylation and morphological changes a few seconds after stimulation by agonists such as phorbol esters which activate PKC. Therefore, taking advantage of parabolic plane flight to obtain sho...

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