3,822 research outputs found
Automated single-cell motility analysis on a chip using lensfree microscopy.
Quantitative cell motility studies are necessary for understanding biophysical processes, developing models for cell locomotion and for drug discovery. Such studies are typically performed by controlling environmental conditions around a lens-based microscope, requiring costly instruments while still remaining limited in field-of-view. Here we present a compact cell monitoring platform utilizing a wide-field (24 mm(2)) lensless holographic microscope that enables automated single-cell tracking of large populations that is compatible with a standard laboratory incubator. We used this platform to track NIH 3T3 cells on polyacrylamide gels over 20 hrs. We report that, over an order of magnitude of stiffness values, collagen IV surfaces lead to enhanced motility compared to fibronectin, in agreement with biological uses of these structural proteins. The increased throughput associated with lensfree on-chip imaging enables higher statistical significance in observed cell behavior and may facilitate rapid screening of drugs and genes that affect cell motility
The infrared imaging spectrograph (IRIS) for TMT: on-instrument wavefront sensors and NFIRAOS interface
The InfraRed Imaging Spectrograph (IRIS) is a first light client science
instrument for the TMT observatory that operates as a client of the NFIRAOS
facility multi-conjugate adaptive optics system. This paper reports on the
concept study and baseline concept design of the On-Instrument WaveFront
Sensors (OIWFS) and NFIRAOS interface subsystems of the IRIS science
instrument, a collaborative effort by NRC-HIA, Caltech, and TMT AO and
Instrument teams. This includes work on system engineering, structural and
thermal design, sky coverage modeling, patrol geometry, probe optics and
mechanics design, camera design, and controls design.Comment: 17 pages, 12 figures, SPIE7735-28
Matrix stiffness affects endocytic uptake of MK2-inhibitor peptides.
In this study, the role of substrate stiffness on the endocytic uptake of a cell-penetrating peptide was investigated. The cell-penetrating peptide, an inhibitor of mitogen-activated protein kinase activated protein kinase II (MK2), enters a primary mesothelial cell line predominantly through caveolae. Using tissue culture polystyrene and polyacrylamide gels of varying stiffness for cell culture, and flow cytometry quantification and enzyme-linked immunoassays (ELISA) for uptake assays, we showed that the amount of uptake of the peptide is increased on soft substrates. Further, peptide uptake per cell increased at lower cell density. The improved uptake seen on soft substrates in vitro better correlates with in vivo functional studies where 10-100 µM concentrations of the MK2 inhibitor cell penetrating peptide demonstrated functional activity in several disease models. Additional characterization showed actin polymerization did not affect uptake, while microtubule polymerization had a profound effect on uptake. This work demonstrates that cell culture substrate stiffness can play a role in endocytic uptake, and may be an important consideration to improve correlations between in vitro and in vivo drug efficacy
End to End Satellite Servicing and Space Debris Management
There is growing demand for satellite swarms and constellations for global
positioning, remote sensing and relay communication in higher LEO orbits. This
will result in many obsolete, damaged and abandoned satellites that will remain
on-orbit beyond 25 years. These abandoned satellites and space debris maybe
economically valuable orbital real-estate and resources that can be reused,
repaired or upgraded for future use. Space traffic management is critical to
repair damaged satellites, divert satellites into warehouse orbits and
effectively de-orbit satellites and space debris that are beyond repair and
salvage. Current methods for on-orbit capture, servicing and repair require a
large service satellite. However, by accessing abandoned satellites and space
debris, there is an inherent heightened risk of damage to a servicing
spacecraft. Sending multiple small-robots with each robot specialized in a
specific task is a credible alternative, as the system is simple and
cost-effective and where loss of one or more robots does not end the mission.
In this work, we outline an end to end multirobot system to capture damaged and
abandoned spacecraft for salvaging, repair and for de-orbiting. We analyze the
feasibility of sending multiple, decentralized robots that can work
cooperatively to perform capture of the target satellite as a first step,
followed by crawling onto damage satellites to perform detailed mapping. After
obtaining a detailed map of the satellite, the robots will proceed to either
repair and replace or dismantle components for salvage operations. Finally, the
remaining components will be packaged with a de-orbit device for accelerated
de-orbit.Comment: 13 pages, 10 figures, Space Traffic Management Conference. arXiv
admin note: text overlap with arXiv:1809.02028, arXiv:1809.04459,
arXiv:1901.0971
Global Microwave Imager (GMI) Spin Mechanism Assembly Design, Development, and Performance Test Results
The GMI Spin Mechanism Assembly (SMA) is a precision bearing and power transfer drive assembly mechanism that supports and spins the Global Microwave Imager (GMI) instrument at a constant rate of 32 rpm continuously for the 3 year plus mission life. The GMI instrument will fly on the core Global Precipitation Measurement (GPM) spacecraft and will be used to make calibrated radiometric measurements at multiple microwave frequencies and polarizations. The GPM mission is an international effort managed by the National Aeronautics and Space Administration (NASA) to improve climate, weather, and hydro-meteorological predictions through more accurate and frequent precipitation measurements [1]. Ball Aerospace and Technologies Corporation (BATC) was selected by NASA Goddard Space Flight Center (GSFC) to design, build, and test the GMI instrument. The SMA design has to meet a challenging set of requirements and is based on BATC space mechanisms heritage and lessons learned design changes made to the WindSat BAPTA mechanism that is currently operating on-orbit and has recently surpassed 8 years of Flight operation
GMI Spin Mechanism Assembly Design, Development, and Test Results
The GMI Spin Mechanism Assembly (SMA) is a precision bearing and power transfer drive assembly mechanism that supports and spins the Global Microwave Imager (GMI) instrument at a constant rate of 32 rpm continuously for the 3 year plus mission life. The GMI instrument will fly on the core Global Precipitation Measurement (GPM) spacecraft and will be used to make calibrated radiometric measurements at multiple microwave frequencies and polarizations. The GPM mission is an international effort managed by the National Aeronautics and Space Administration (NASA) to improve climate, weather, and hydro-meteorological predictions through more accurate and frequent precipitation measurements [1]. Ball Aerospace and Technologies Corporation (BATC) was selected by NASA Goddard Space Flight Center (GSFC) to design, build, and test the GMI instrument. The SMA design has to meet a challenging set of requirements and is based on BATC space mechanisms heritage and lessons learned design changes made to the WindSat BAPTA mechanism that is currently operating on orbit and has recently surpassed 8 years of Flight operation
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