scholarly journals Scanned aperture polarized light microscope with liquid crystal compensator

2003 ◽  
Vol 9 (S02) ◽  
pp. 1154-1155
Author(s):  
M. Shribak ◽  
R. Oldenbourg
Keyword(s):  
Liquid Crystal ◽  
Light Microscope ◽  
Polarized Light

scholarly journals Chromosome Malorientations after Meiosis II Arrest Cause Nondisjunction

2007 ◽  
Vol 18 (5) ◽  
pp. 1645-1656 ◽  
Author(s):  
Marie A. Janicke ◽  
Loren Lasko ◽  
Rudolf Oldenbourg ◽  
James R. LaFountain
Keyword(s):  
Liquid Crystal ◽  
Light Microscope ◽  
Daughter Nucleus ◽  
Polarized Light ◽  
Live Cell ◽  
The Other ◽  
Sister Kinetochore ◽  
Microscope Imaging ◽  
Birefringent Fiber ◽  
Spindle Elongation

This study investigated the basis of meiosis II nondisjunction. Cold arrest induced a fraction of meiosis II crane fly spermatocytes to form (n + 1) and (n − 1) daughters during recovery. Live-cell liquid crystal polarized light microscope imaging showed nondisjunction was caused by chromosome malorientation. Whereas amphitely (sister kinetochore fibers to opposite poles) is normal, cold recovery induced anaphase syntely (sister fibers to the same pole) and merotely (fibers to both poles from 1 kinetochore). Maloriented chromosomes had stable metaphase positions near the equator or between the equator and a pole. Syntelics were at the spindle periphery at metaphase; their sisters disconnected at anaphase and moved all the way to a centrosome, as their strongly birefringent kinetochore fibers shortened. The kinetochore fibers of merotelics shortened little if any during anaphase, making anaphase lag common. If one fiber of a merotelic was more birefringent than the other, the less birefringent fiber lengthened with anaphase spindle elongation, often permitting inclusion of merotelics in a daughter nucleus. Meroamphitely (near amphitely but with some merotely) caused sisters to move in opposite directions. In contrast, syntely and merosyntely (near syntely but with some merotely) resulted in nondisjunction. Anaphase malorientations were more frequent after longer arrests, with particularly long arrests required to induce syntely and merosyntely.

The Birefringence of thin filaments measured with the Pol-Scope

1997 ◽  
Vol 3 (S2) ◽  
pp. 797-798
Author(s):  
R. Oldenbourg ◽  
Edward D. Salmon ◽  
Phong T. Tran
Keyword(s):  
Liquid Crystal ◽  
Light Microscope ◽  
Living Cell ◽  
Polarized Light ◽  
Molecular Transport ◽  
Thin Filaments ◽  
Dense Networks ◽  
Cell Functions ◽  
Vital Cell ◽  
Filament Networks

The living cell is criss-crossed by dense networks of filaments providing mechanic stability, site directed molecular transport and support of other vital cell functions. With the polarized light microscope we can observe the birefringence associated with thin filaments or partially oriented filament networks and measure the birefringence directly in the living cell (Fig. 1). Filament birefringence is a consequence of the elongated shape of the molecules and occurs naturally without the need to stain or label them, as is necessary in fluorescence imaging.We have measured the birefringence of microtubules and axoneme filaments using the new polarized light microscope (Pol-Scope).The design of the Pol-Scope is based on the traditional polarized light microscope in which the crystal compensator is replaced by a universal compensator made from two liquid crystal variable retarders. Electronic image acquisition in the Pol-Scope is synchronized to liquid crystal settings to capture a sequence of four images with circular and elliptical polarization.

High-resolution measurement of birefringent fine structure in living cells using a new polarized light microscope

1995 ◽  
Vol 53 ◽  
pp. 54-55
Author(s):  
Rudolf Oldenbourg
Keyword(s):  
Light Microscope ◽  
Fluorescent Dyes ◽  
Polarized Light ◽  
Processing System ◽  
Video Camera ◽  
Molecular Organization ◽  
Computer Assisted ◽  
Image Recording ◽  
Birefringent Crystal ◽  
Technological Advances

The recent renaissance of the light microsope is fueled in part by technological advances in components on the periphery of the microscope, such as the laser as illumination source, electronic image recording (video), computer assisted image analysis and the biochemistry of fluorescent dyes for labeling specimens. After great progress in these peripheral parts, it seems timely to examine the optics itself and ask how progress in the periphery facilitates the use of new optical components and of new optical designs inside the microscope. Some results of this fruitful reflection are presented in this symposium.We have considered the polarized light microscope, and developed a design that replaces the traditional compensator, typically a birefringent crystal plate, with a precision universal compensator made of two liquid crystal variable retarders. A video camera and digital image processing system provide fast measurements of specimen anisotropy (retardance magnitude and azimuth) at ALL POINTS of the image forming the field of view. The images document fine structural and molecular organization within a thin optical section of the specimen.

New polarized-light microscope for fast and orientation independent measurement of birefringent fine structure

1993 ◽  
Vol 51 ◽  
pp. 82-83
Author(s):  
Rudolf Oldenbourg
Keyword(s):  
Light Microscope ◽  
Polarized Light ◽  
Video Camera ◽  
Limited Range ◽  
Image Point ◽  
Computer Assisted ◽  
Optical Modulators ◽  
Anisotropic Structures ◽  
Long Time ◽  
Computer Assisted Image

The polarized light microscope has the unique potential to measure submicroscopic molecular arrangements dynamically and non-destructively in living cells and other specimens. With the traditional pol-scope, however, single images display only those anisotropic structures that have a limited range of orientations with respect to the polarization axes of the microscope. Furthermore, rapid measurements are restricted to a single image point or single area that exhibits uniform birefringence or other form of optical anisotropy, while measurements comparing several image points take an inordinately long time.We are developing a new kind of polarized light microscope which combines speed and high resolution in its measurement of the specimen anisotropy, irrespective of its orientation. The design of the new pol-scope is based on the traditional polarized light microscope with two essential modifications: circular polarizers replace linear polarizers and two electro-optical modulators replace the traditional compensator. A video camera and computer assisted image analysis provide measurements of specimen anisotropy in rapid succession for all points of the image comprising the field of view.

Light microscopy of ceramics

1993 ◽  
Vol 51 ◽  
pp. 908-909
Author(s):  
Walter C. McCrone
Keyword(s):  
Refractive Index ◽  
Light Microscopy ◽  
Light Microscope ◽  
Polarized Light ◽  
Refractive Indices ◽  
Complete Coverage ◽  
The Subject ◽  
Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

scholarly journals Design and Realization of a Compact Efficient Beam Combiner, Based on Liquid Crystal Pancharatnam–Berry Phase Gratings

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 220
Author(s):  
Boxuan Gao ◽  
Jeroen Beeckman ◽  
Kristiaan Neyts
Keyword(s):  
Liquid Crystal ◽  
Berry Phase ◽  
Polarized Light ◽  
Laser Beams ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Beam Combiner ◽  
High Diffraction Efficiency ◽  
High Diffraction ◽  
Crystal Mixture

We demonstrate a laser beam combiner based on four photo-patterned Pancharatnam–Berry (PB) phase gratings, which is compact and has high diffraction efficiency for incident circularly polarized light. The nematic liquid crystal mixture E7 is used as anisotropic material, and the thickness of the layer is controlled by spacers. The beam combiner can bring two parallel laser beams closer to each other while remaining parallel. This work shows the potential to realize components based on flat optical LC devices.

Lamellar Lyotropic Liquid Crystal Phases as a Carrier for Skin Delivery of Morus alba Stem Extract

2021 ◽  
Vol 901 ◽  
pp. 67-72
Author(s):  
Chein Yhirayha ◽  
Sakchai Wittaya-Areekul ◽  
Tasana Pitaksuteepong
Keyword(s):  
Liquid Crystal ◽  
Biological Activities ◽  
Polarized Light ◽  
Water Extract ◽  
Skin Penetration ◽  
Morus Alba ◽  
Lyotropic Liquid Crystal ◽  
Mixed Surfactant ◽  
Skin Delivery ◽  
Stem Extract

Morus alba stem extract possesses several biological activities. However, skin delivery of the extract is limited by the stratum corneum. In this study, lamellar lyotropic liquid crystal (LLC) was investigated for the potential application in the skin delivery of M. alba stem extract. The four formulations were developed and incorporated with M. alba stem extract at 3% w/w. These formulations were stored at room temperature in light-protected containers for 3 months. The optical pattern under polarized light microscope, viscosity and remaining of the extract were determined. The skin penetration enhancing property of the formulations was investigated using excised porcine ear skin model. The results showed that all formulations remained stable after 3-month storage. The two formulations exhibiting good penetration enhancing properties were F3 consisting of PEG-7 glyceryl cocoate/n-Dodecane/Water/extract (55.29/19.40/22.31/3.00 %w/w) and F4 consisting of mixed Surfactant/n-Dodecane/Water/extract (48.50/4.85/43.65/3.00 %w/w). The mixed surfactant composed of PEG-7 glyceryl cocoate/PEG-40 hydrogenated castor oil/Glyceryl oleate (40/33.24/26.76 %w/w). It can be concluded that the lamellar LLC formulations developed in this study can be used as a carrier for delivering of M. alba stem extract. The components of the formulations which play important roles are the oil and the surfactant.

Study on the Crystalline Morphology of HDPE/E-TMB Blends

2012 ◽  
Vol 200 ◽  
pp. 406-410
Author(s):  
Wei Hua Fan ◽  
Ren Jie Wang ◽  
Yu Kun Liu ◽  
Kai Guo ◽  
Jin Zhou Chen ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Light Microscope ◽  
Polarized Light ◽  
Crystalline Morphology ◽  
Master Batch

HE1/E-TMB and HE2/E-TMB blends are prepared by thermal mechanical blending of toughening master batch (E-TMB) with 2200JHDPE (HE1) and 5000SHDPE (HE2), respectively. The crystalline morphology of HE1/E-TMB and HE2/E-TMB blends were studied with polarized light microscope (PLM), and compared with those of HE1/E-SMB and HE2/E-SMB blends. The results showed that the crystallite size of HDPE/E-TMB and HE/E-SMB blends was remarkably smaller than that of the pure HDPE, while the number of the crystals increased. At the same elastomer content, the refined extend of the crystallite of HE2/E-TMB blends obviously increased than that of the HE1/E-TMB blends. The number of the crystal gradually increased and the crystallite size substantially reduced with the elastomers ratio (M/N) increasing. The refined extend of the crystallite of HDPE/E-TMB blends gradually enhanced and the number of the crystal substantially increased as the elastomer content gradually growing.

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