scholarly journals A magnetically enabled simulation of microgravity represses the auxin response during early seed germination on a microfluidic platform

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Jing Du ◽  
Lin Zeng ◽  
Zitong Yu ◽  
Sihui Chen ◽  
Xi Chen ◽  
...  
Keyword(s):  
Simulated Microgravity ◽  
Critical Factor ◽  
Vital Role ◽  
Microgravity Environment ◽  
Biological Study ◽  
Gravitational Acceleration ◽  
Auxin Response ◽  
Microfluidic Platform ◽  
Microgravity Conditions ◽  
On Chip

AbstractFor plants on Earth, the phytohormone auxin is essential for gravitropism-regulated seedling establishment and plant growth. However, little is known about auxin responses under microgravity conditions due to the lack of a tool that can provide an alteration of gravity. In this paper, a microfluidic negative magnetophoretic platform is developed to levitate Arabidopsis seeds in an equilibrium plane where the applied magnetic force compensates for gravitational acceleration. With the benefit of the microfluidic platform to simulate a microgravity environment on-chip, it is found that the auxin response is significantly repressed in levitated seeds. Simulated microgravity statistically interrupts auxin responses in embryos, even after chemical-mediated auxin alterations, illustrating that auxin is a critical factor that mediates the plant response to gravity alteration. Furthermore, pretreatment with an auxin transportation inhibitor (N-1-naphthylphthalamic acid) enables a decrease in the auxin response, which is no longer affected by simulated microgravity, demonstrating that polar auxin transportation plays a vital role in gravity-regulated auxin responses. The presented microfluidic platform provides simulated microgravity conditions in an easy-to-implement manner, helping to study and elucidate how plants correspond to diverse gravity conditions; in the future, this may be developed into a versatile tool for biological study on a variety of samples.

scholarly journals The Study of the Mechanism of Protein Crystallization in Space by Using Microchannel to Simulate Microgravity Environment

Crystals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 400 ◽  
Author(s):  
Yong Yu ◽  
Kai Li ◽  
Hai Lin ◽  
Ji-Cheng Li
Keyword(s):  
Growth Rates ◽  
Simulated Microgravity ◽  
Crystal Surface ◽  
Protein Crystallization ◽  
Experimental Results ◽  
Protein Crystals ◽  
Microgravity Environment ◽  
Microgravity Conditions ◽  
Lysozyme Crystals ◽  
Lysozyme Crystal

Space is expected to be a convection-free, quiescent environment for the production of large-size and high-quality protein crystals. However, the mechanisms by which the diffusion environment in space improves the quality of the protein crystals are not fully understood. The interior of a microfluidic device can be used to simulate a microgravity environment to investigate the protein crystallization mechanism that occurs in space. In the present study, lysozyme crystals were grown in a prototype microchannel device with a height of 50 μm in a glass-polydimethylsiloxane (PDMS)-glass sandwich structure. Comparative experiments were also conducted in a sample pool with a height of 2 mm under the same growth conditions. We compared the crystal morphologies and growth rates of the grown crystals in the two sample pools. The experimental results showed that at very low initial supersaturation, the morphology and growth rates of lysozyme crystals under the simulated microgravity conditions is similar to that on Earth. With increasing initial supersaturation, a convection-free, quiescent environment is better for lysozyme crystal growth. When the initial supersaturation exceeded a threshold, the growth of the lysozyme crystal surface under the simulated microgravity conditions never completely transform from isotropic to anisotropic. The experimental results showed that the convection may have a dual effect on the crystal morphology. Convection can increase the roughness of the crystal surface and promote the transformation of the crystal form from circular to tetragonal during the crystallization process.

A novel microfluidic platform with stable concentration gradient for on chip cell culture and screening assays

Lab on a Chip ◽  
2013 ◽  
Vol 13 (18) ◽  
pp. 3714 ◽  
Author(s):  
Bi-Yi Xu ◽  
Shan-Wen Hu ◽  
Guang-Sheng Qian ◽  
Jing-Juan Xu ◽  
Hong-Yuan Chen
Keyword(s):  
Cell Culture ◽  
Concentration Gradient ◽  
Microfluidic Platform ◽  
Screening Assays ◽  
On Chip

An automated centrifugal microfluidic assay for whole blood fractionation and isolation of multiple cell populations using an aqueous two-phase system

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Byeong-Ui Moon ◽  
Liviu Clime ◽  
Daniel Brassard ◽  
Alex Boutin ◽  
Jamal Daoud ◽  
...  
Keyword(s):  
Human Blood ◽  
Whole Blood ◽  
Cell Populations ◽  
Phase System ◽  
Two Phase ◽  
Microfluidic Platform ◽  
Aqueous Two Phase System ◽  
Separation Layers ◽  
Multiple Cell ◽  
On Chip

This paper describes an advanced on-chip whole human blood fractionation and cell isolation process combining an aqueous two-phase system to create complex separation layers with a centrifugal microfluidic platform to control and automate the assay.

A Polymer-Based Microfluidic Platform Featuring On-Chip Actuated Hydrogel Valves for Disposable Applications

2010 ◽  
Vol 19 (4) ◽  
pp. 944-950 ◽  
Author(s):  
Emil J. Geiger ◽  
Albert P. Pisano ◽  
Frantisek Svec
Keyword(s):  
Microfluidic Platform ◽  
On Chip

scholarly journals The Effects of Simulated Microgravity on Macrophage Phenotype

Biomedicines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1205
Author(s):  
Christopher Ludtka ◽  
Erika Moore ◽  
Josephine B. Allen
Keyword(s):  
Protein Expression ◽  
Simulated Microgravity ◽  
Prolonged Exposure ◽  
Cell Function ◽  
Immune Cell ◽  
Expression Profiles ◽  
Microgravity Environment ◽  
M2 Macrophage ◽  
Macrophage Function ◽  
Gene And Protein Expression

The effects of spaceflight, including prolonged exposure to microgravity, can have significant effects on the immune system and human health. Altered immune cell function can lead to adverse health events, though precisely how and to what extent a microgravity environment impacts these cells remains uncertain. Macrophages, a key immune cell, effect the inflammatory response as well as tissue remodeling and repair. Specifically, macrophage function can be dictated by phenotype that can exist between spectrums of M0 macrophage: the classically activated, pro-inflammatory M1, and the alternatively activated, pro-healing M2 phenotypes. This work assesses the effects of simulated microgravity via clinorotation on M0, M1, and M2 macrophage phenotypes. We focus on phenotypic, inflammatory, and angiogenic gene and protein expression. Our results show that across all three phenotypes, microgravity results in a decrease in TNF-α expression and an increase in IL-12 and VEGF expression. IL-10 was also significantly increased in M1 and M2, but not M0 macrophages. The phenotypic cytokine expression profiles observed may be related to specific gravisensitive signal transduction pathways previously implicated in microgravity regulation of macrophage gene and protein expression. Our results highlight the far-reaching effects that simulated microgravity has on macrophage function and provides insight into macrophage phenotypic function in microgravity.

scholarly journals Droplet-assisted electrospray phase separation using an integrated silicon microfluidic platform

Lab on a Chip ◽  
2022 ◽  
Author(s):  
Yan Zhang ◽  
Sungho Kim ◽  
Weihua Shi ◽  
Yaoyao Zhao ◽  
Insu Park ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Phase Separation ◽  
Electrospray Ionization ◽  
Mass Spectrometry Analysis ◽  
Microfluidic Channels ◽  
Droplet Generator ◽  
Microfluidic Platform ◽  
Spectrometry Analysis ◽  
Temporal Phase ◽  
On Chip

We report on a silicon microfluidic platform that enables integration of transparent μm-scale microfluidic channels, an on-chip pL-volume droplet generator, and a nano-electrospray ionization emitter that enables spatial and temporal phase separation for mass spectrometry analysis.

scholarly journals Functional alterations of root meristematic cells of Arabidopsis thaliana induced by a simulated microgravity environment

2016 ◽  
Vol 207 ◽  
pp. 30-41 ◽  
Author(s):  
Elodie Boucheron-Dubuisson ◽  
Ana I. Manzano ◽  
Isabel Le Disquet ◽  
Isabel Matía ◽  
Julio Sáez-Vasquez ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Simulated Microgravity ◽  
Microgravity Environment ◽  
Meristematic Cells ◽  
Root Meristematic Cells

Optimized High Power GaN Transistors

2015 ◽  
Vol 2015 (HiTEN) ◽  
pp. 000195-000199
Author(s):  
J. Roberts ◽  
A. Mizan ◽  
L. Yushyna
Keyword(s):  
High Speed ◽  
Figure Of Merit ◽  
Printed Circuit Board ◽  
Heat Removal ◽  
Vital Role ◽  
Circuit Board ◽  
Die Structure ◽  
Power Switches ◽  
On Chip ◽  
Very High

GaN transistors intended for use at 600–900 V and that are capable of providing of 30–100 A are being introduced this year. These devices have a substantially better switching Figure-of-Merit (FOM) than silicon power switches. Rapid market acceptance is expected leading to compound annual growth rates of 85 %. However these devices present new packaging challenges. Their high speed combined with the very high current being switched demands that very low inductance packaging must be combined with highly controlled drive circuitry. While convention, and the usually vertical power device die structure, has largely determined power transistor package formats in the past, the lateral nature of the today GaN devices requires the use of new package types. The new packages have to operate at high temperatures while providing effective heat removal, low inductance, and low series resistance. Because GaN devices are lateral they require the package metal tracks to be integrated within the on-chip tracks to carry the current away from the thin on-chip metal tracks. The new GaN devices are available in two formats: one for use in embedded modular assemblies and the other for use mounted upon conventional circuit board systems. The package intended for discrete printed circuit board (PCB) assemblies has a top side cooling option that simplifies the thermal interface to the heat sink. The paper describes the die layout including the added copper tracks. The corresponding package elements that interface directly with the surface of the die play a vital role in terms of the current handling. They also provide the interface to the external busbars that allow the package to be mounted within, or on PCB. The assembly has been subject to extensive thermal analysis and the performance of a 30 A, 650 V transistor is described.

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