A single microparticle launching method is described to simulate the hypervelocity impacts of micrometeoroids and microdebris on space structures at the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency. A microparticle placed in a sabot with slits is accelerated using a rifled two-stage light-gas gun. The centrifugal force provided by the rifling in the launch tube separates the sabot. The sabot-separation distance and the impact-point deviation are strongly affected by the combination of the sabot diameter and the bore diameter, and by the projectile diameter. Using this method, spherical projectiles of 1.0-0.1 mm diameter were launched at up to 7 km/s.
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http://dx.doi.org/10.1063/1.3498896 | DOI Listing |
Phys Rev Lett
December 2024
Laboratoire De Physique de l'École Normale Supérieure, ENS, PSL, CNRS, Sorbonne Université, Université de Paris, 24 rue Lhomond, 75005 Paris, France.
Adv Sci (Weinh)
December 2024
Control and Manipulation of Microscale Living Objects, Center for Translational Cancer Research (TranslaTUM), Munich Institute of Biomedical Engineering (MIBE), Department of Electrical Engineering, School of Computation, Information and Technology (CIT), Technical University of Munich, Einsteinstraße 25, 81675, Munich, Germany.
Microparticle-templated droplets or dropicles have recently gained interest in the fields of diagnostic immunoassays, single-cell analysis, and digital molecular biology. Amphiphilic particles have been shown to spontaneously capture aqueous droplets within their cavities upon mixing with an immiscible oil phase, where each particle templates a single droplet. Here, an amphiphilic microparticle with four discrete hydrophilic patches embedded at the inner corners of a square-shaped hydrophobic outer ring of the particle (4C particle) is fabricated.
View Article and Find Full Text PDFMethods Mol Biol
December 2024
Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM, Montpellier, France.
The bacterial flagellar motor (BFM) is a rotary molecular machine that drives critical bacterial processes including motility, chemotaxis, biofilm formation, and infection. For over two decades, the bead assay, which measures the rotation of a microparticle attached to the flagellum of a surface-attached bacterium, has been instrumental in deciphering the motor's biophysical mechanisms. This technique has not only quantified the rotational speed and frequency of directional switching as a function of the viscous load on the flagellum but has also revealed the BFM's capacity for mechanosensitive speed modulation, adapting to environmental conditions.
View Article and Find Full Text PDFJ Vis Exp
November 2024
Department of Haematology, University Hospital of Bordeaux; Inserm U1034, Biology of Cardiovascular Disease.
Activated platelets promote coagulation primarily by exposing the procoagulant phospholipid phosphatidylserine (PS) on their outer membrane surfaces and releasing PS-expressing microvesicles that retain the original membrane architecture and cytoplasmic components of their originating cells. The accessibility of phosphatidylserine facilitates the binding of major coagulation factors, significantly amplifying the catalytic efficiency of coagulation enzymes, while microvesicle release acts as a pivotal mediator of intercellular signaling. Procoagulant platelets play a crucial role in clot stabilization during hemostasis, and their increased proportion in the bloodstream correlates with an increased risk of thrombosis.
View Article and Find Full Text PDFElectrophoresis
December 2024
State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an JiaoTong University, Xi'an, People's Republic of China.
On-line counting of the microparticle/bacteria in the liquid medium has great potential in the food safety and biomedical fields. A new low-cost microfluidic device is proposed for the on-line counting of the microparticles/bacteria in the liquid medium. The gradually contracted microchannel and the viscoelastic fluid are combined to achieve the efficient elastic focusing of the particle/bacteria, which significantly improves the counting accuracy by aligning all particles/bacteria in a single position at the center of the microchannel.
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