Three-dimensional coherent transfer function for a confocal microscope with two D-shaped pupils

2009 ◽  
Vol 48 (5) ◽  
pp. 810 ◽  
Author(s):  
Ke Si ◽  
Wei Gong ◽  
Colin J. R. Sheppard
Keyword(s):  
Transfer Function ◽  
Three Dimensional ◽  
Confocal Microscope

Density-based discrimination of protein and RNA in the ribosome

1992 ◽  
Vol 50 (1) ◽  
pp. 464-465
Author(s):  
Joachim Frank
Keyword(s):  
Transfer Function ◽  
Spatial Frequency ◽  
Three Dimensional ◽  
Wiener Filter ◽  
Dark Field Image ◽  
Dark Field ◽  
Frequency Range ◽  
Bright Field ◽  
Contrast Transfer Function ◽  
Pass Filter

Cryo-electron microscopy combined with single-particle reconstruction techniques has allowed us to form a three-dimensional image of the Escherichia coli ribosome.In the interior, we observe strong density variations which may be attributed to the difference in scattering density between ribosomal RNA (rRNA) and protein. This identification can only be tentative, and lacks quantitation at this stage, because of the nature of image formation by bright field phase contrast. Apart from limiting the resolution, the contrast transfer function acts as a high-pass filter which produces edge enhancement effects that can explain at least part of the observed variations. As a step toward a more quantitative analysis, it is necessary to correct the transfer function in the low-spatial-frequency range. Unfortunately, it is in that range where Fourier components unrelated to elastic bright-field imaging are found, and a Wiener-filter type restoration would lead to incorrect results. Depending upon the thickness of the ice layer, a varying contribution to the Fourier components in the low-spatial-frequency range originates from an “inelastic dark field” image. The only prospect to obtain quantitatively interpretable images (i.e., which would allow discrimination between rRNA and protein by application of a density threshold set to the average RNA scattering density may therefore lie in the use of energy-filtering microscopes.

Optical transfer function of three-dimensional photonic crystals by volume holographic recording

2013 ◽  
Vol 103 (4) ◽  
pp. 041106 ◽  
Author(s):  
Susanna Orlic ◽  
Fabian Bernstein ◽  
Christoph Kratz ◽  
Alexander Schlösser
Keyword(s):  
Transfer Function ◽  
Photonic Crystals ◽  
Three Dimensional ◽  
Holographic Recording ◽  
Optical Transfer Function ◽  
Optical Transfer

Active and Passive Responses of Myofibroblasts in Response to Mechanical Stretching in 3D Culture

2008 ◽  
Author(s):  
Adam C. Nathan ◽  
Sheng-Lin Lee ◽  
J. Pablo Marquez ◽  
Tao Ju ◽  
Kenneth M. Pryse ◽  
...  
Keyword(s):  
Mechanical Testing ◽  
Cell Response ◽  
Three Dimensional ◽  
3D Culture ◽  
Confocal Microscope ◽  
Effective Resistance ◽  
Optical Measurements ◽  
Mechanical Stretching ◽  
Stretch Response ◽  
Cells Cultured

The stretch response of myofibroblast cells cultured in a three-dimensional environment was simultaneously measured and observed using a tissue stretching apparatus mounted to a confocal microscope. Optical measurements were used to assess mechanical estimates of cell response obtained through combined mechanical testing and biochemical inhibition. Results show that activated myofibroblasts provide an effective resistance on the order of 100s of kPa. In specific mechanical environments, stretched myofibroblasts release the ECM.

scholarly journals Gravity wave propagation in the realistic atmosphere based on a three-dimensional transfer function model

2007 ◽  
Vol 25 (9) ◽  
pp. 1979-1986 ◽  
Author(s):  
L. Sun ◽  
W. Wan ◽  
F. Ding ◽  
T. Mao
Keyword(s):  
Transfer Function ◽  
Gravity Wave ◽  
Gravity Waves ◽  
Minimum Energy ◽  
Three Dimensional ◽  
Wave Number ◽  
Transfer Function Model ◽  
Wave Band ◽  
Function Model ◽  
Ionospheric Height

Abstract. In order to study the filter effect of the background winds on the propagation of gravity waves, a three-dimensional transfer function model is developed on the basis of the complex dispersion relation of internal gravity waves in a stratified dissipative atmosphere with background winds. Our model has successfully represented the main results of the ray tracing method, e.g. the trend of the gravity waves to travel in the anti-windward direction. Furthermore, some interesting characteristics are manifest as follows: (1) The method provides the distribution characteristic of whole wave fields which propagate in the way of the distorted concentric circles at the same altitude under the control of the winds. (2) Through analyzing the frequency and wave number response curve of the transfer function, we find that the gravity waves in a wave band of about 15–30 min periods and of about 200–400 km horizontal wave lengths are most likely to propagate to the 300-km ionospheric height. Furthermore, there is an obvious frequency deviation for gravity waves propagating with winds in the frequency domain. The maximum power of the transfer function with background winds is smaller than that without background winds. (3) The atmospheric winds may act as a directional filter that will permit gravity wave packets propagating against the winds to reach the ionospheric height with minimum energy loss.

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