نتایج جستجو برای: microgravity condition

تعداد نتایج: 317796  

پایان نامه :دانشگاه تربیت معلم - سبزوار - دانشکده ادبیات و زبانهای خارجی 1390

this study investigated the effects of planning on second-language written production with regard to task type. the participants were 75 iranian learners of english as a foreign language attending a private foreign language institution. they were asked to complete two different types of writing tasks (expository writing task and argumentative writing task) in different planned conditions (indiv...

2011
D. S. Schaffhauser O. Andrini C. Ghezzi M. Schaffner

A non-invasive electrophysiology system for performing rapid measurements on Xenopus laevis oocytes under varying gravity levels is presented. Our novel approach makes the need for inserting microelectrodes into the cytosol unnecessary. Immobilization of the oocyte on top of an orifice is achieved using a slight air overpressure to ensure that the cell is kept in a stable condition even under v...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2005
Hiroo Totsuji Chieko Totsuji Takafumi Ogawa Kenji Tsuruta

Structure formation of dust particles in dusty plasmas under microgravity has been simulated by the molecular dynamics method. It is shown that, at low temperatures, dust particles are organized into layered spherical shells. The number of shells is a function of the system size and the strength of screening by ambient plasma particles, while the dependency on the latter is much weaker. In the ...

Journal: :Physical review letters 2013
N Murdoch B Rozitis K Nordstrom S F Green P Michel T-L de Lophem W Losert

We investigate the role of gravity on convection in a dense granular shear flow. Using a microgravity-modified Taylor-Couette shear cell under the conditions of parabolic flight microgravity, we demonstrate experimentally that secondary, convective-like flows in a sheared granular material are close to zero in microgravity and enhanced under high-gravity conditions, though the primary flow fiel...

Journal: :International journal of clinical and experimental pathology 2014
Wenjun Jiang Bingxin Xu Yong Yi Yuling Huang Xiao-Ou Li Fuquan Jiang Jinlian Zhou Jianzhong Zhang Yan Cui

During the spaceflight, a wide variety of microorganisms may be carried to the outer space by astronauts and aviation component. The yeast Candida albicans is an important opportunistic pathogen responsible for a variety of cutaneous and systemic human infections in human body, and the yeast cell itself could be affected by various stressful environmental factors including the weightless enviro...

2013
Zhongquan Dai Feng Wu Jian Chen Hongjie Xu Honghui Wang Feima Guo Yingjun Tan Bai Ding Jinfu Wang Yumin Wan Yinghui Li

Microgravity decreases osteoblastic activity, induces actin microfilament disruption and inhibits the responsiveness of osteoblast to cytokines, but the mechanisms remains enigmatic. The F-actin cytoskeleton has previously been implicated in manifold changes of cell shape, function and signaling observed under microgravity. Here we investigate the involvement of microfilament in mediating the e...

Journal: :Molecular vision 2006
Joan E Roberts Barbara M Kukielczak Colin F Chignell Bob H Sik Dan-Ning Hu Mary Ann Principato

PURPOSE The goal of this study was to determine the potential damage to the human retina that may occur from weightlessness during space flight using simulated microgravity. METHODS Human retinal pigment epithelial (hRPE) cells were cultured for 24 h in a National Aeronautics and Space Administration-designed rotating wall bioreactor vessel to mimic the microgravity environment of space. Sing...

2015
Danilo Ranieri Alessandra Cucina Mariano Bizzarri Maurizio Alimandi Maria Rosaria Torrisi

Microgravity and sudden changes of gravitational forces exert numerous effects on tissues, organs and apparatus. Responses to these forces variably applied to cells indicate the existence of mechanotransduction pathways able to modulate transcription. Oscillation of circadian clocks similarly influences many cellular and metabolic processes. Here we hypothesized that signals derived from change...

2015
Peter William Taylor

Manned space flight induces a reduction in immune competence among crew and is likely to cause deleterious changes to the composition of the gastrointestinal, nasal, and respiratory bacterial flora, leading to an increased risk of infection. The space flight environment may also affect the susceptibility of microorganisms within the spacecraft to antibiotics, key components of flown medical kit...

2013
Hiroaki Tanaka Susumu Sasaki Sachiko Takahashi Koji Inaka Yoshio Wada Mitsugu Yamada Kazunori Ohta Hiroshi Miyoshi Tomoyuki Kobayashi Shigeki Kamigaichi

It is said that the microgravity environment positively affects the quality of protein crystal growth. The formation of a protein depletion zone and an impurity depletion zone due to the suppression of convection flow were thought to be the major reasons. In microgravity, the incorporation of molecules into a crystal largely depends on diffusive transport, so the incorporated molecules will be ...

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