scholarly journals Rediscovery of Darkfieid Dispersion Staining while Building a Universal Student Microscope

2003 ◽  
Vol 11 (1) ◽  
pp. 24-28
Author(s):  
Theodore M. Clarke
Keyword(s):  
Light Source ◽  
Light Microscope ◽  
Fiber Optic ◽  
Light Guide ◽  
Polarized Light ◽  
Cover Glass ◽  
Artistic Value ◽  
Aperture Diaphragm ◽  
Reflected Light

My first universal student microscope, shown in Figure 1, began life as a Monolux microscope from the 1960rs. Its development into a universal student microscope began when my wife wanted a polarized light microscope with the ability to photograph microscopic crystals under a cover glass for their artistic value. My background as a metallurgist was with the reflected light metallurgical microscope, I have also designed and built vertical illuminators for brightfield illumination of complete metal log raphic specimens using a fiber optic light guide end as the light source with lens configurations giving an imaged field diaphragm and an illumination aperture diaphragm imaged in the aperture of the macro lens.

Design of a Fiber Optic Pressure Transducer

1977 ◽  
Vol 99 (1) ◽  
pp. 274-279 ◽  
Author(s):  
R. H. Pahler ◽  
A. S. Roberts
Keyword(s):  
Light Intensity ◽  
Light Source ◽  
Pressure Transducer ◽  
Fiber Optic ◽  
Light Guide ◽  
Circular Array ◽  
Analytic Procedure ◽  
Reflected Light ◽  
Cylindrical Metal ◽  
Selection Of

Performance characteristics of a fiber optic pressure transducer are presented and discussed. The transducer consists of a cylindrical metal housing with a specular reflecting aluminum diaphragm at the distal end and a circular array of fiber optic light guide bundles at the proximal end. The center bundle is connected to a light source with the surrounding bundles carrying reflected light to a photodetector. A change in pressure on the diaphragm produces a differential change in light intensity. An analytic procedure guides the selection of an optimal configuration in order to obtain maximum transducer response.

Phagocytosis by Kupffer cells predominates in pericentral regions of the liver lobule

1990 ◽  
Vol 259 (5) ◽  
pp. G814-G821 ◽  
Author(s):  
J. M. te Koppele ◽  
R. G. Thurman
Keyword(s):  
Kupffer Cells ◽  
Fiber Optic ◽  
Light Guide ◽  
Carbon Uptake ◽  
Liver Lobule ◽  
Particle Uptake ◽  
Carbon Particles ◽  
Reflected Light ◽  
Large Fiber ◽  
Light Guides

These studies were designed to determine whether particle phagocytosis could be monitored from the surface of the perfused liver. To achieve this goal, decreases in reflected light were measured during phagocytosis of colloidal carbon particles. Livers were illuminated with 623-nm light via a relatively large fiber-optic light guide (tip diam 2 mm), and reflected light was monitored continuously. A decrease in reflected light was observed when carbon was infused that was proportional to the influent carbon concentration. Initial changes in reflected light were linearly related to rates of carbon uptake by Kupffer cells. Subsequently, rates of carbon uptake were determined from changes in reflected light in periportal and pericentral regions of the liver lobule with miniature fiber-optic light guides. In perfusions in the anterograde direction, rates of carbon uptake were approximately 80% higher in pericentral than periportal regions of the liver lobule. This pattern was reversed when livers were perfused in the retrograde direction. Thus particle phagocytosis predominates in downstream regions of the liver lobule. Because decreasing the pH of the influent perfusate increased carbon uptake, the pH gradient over the liver lobule may be involved in the regulation of particle uptake at the sublobular level.

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).

Dalnegroite, Tl5–xPb2x(As,Sb)2l–xS34, a new thallium sulphosalt from Lengenbach quarry, Binntal, Switzerland

2009 ◽  
Vol 73 (6) ◽  
pp. 1027-1032 ◽  
Author(s):  
F. Nestola ◽  
A. Guastoni ◽  
L. Bindi ◽  
L. Secco
Keyword(s):  
Polarized Light ◽  
New Mineral ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Concentrations ◽  
Reflected Light ◽  
Mohs Hardness ◽  
The Mean ◽  
The University ◽  
Probable Space

AbstractDalnegroite, ideally Tl4Pb2(As12Sb8)Σ20S34, is a new mineral from Lengenbach, Binntal, Switzerland. It occurs as anhedral to subhedral grains up to 200 μm across, closely associated with realgar, pyrite, Sb-rich seligmanite in a gangue of dolomite. Dalnegroite is opaque with a submetallic lustre and shows a brownish-red streak. It is brittle; the Vickers hardness (VHN25) is 87 kg mm-2(range: 69—101) (Mohs hardness ∼3—3½). In reflected light, dalnegroite is highly bireflectant and weakly pleochroic, from white to a slightly greenish-grey. In cross-polarized light, it is highly anisotropic with bluish to green rotation tints and red internal reflections.According to chemical and X-ray diffraction data, dalnegroite appears to be isotypic with chabournéite, Tl5-xPb2x(Sb,As)21-xS34. It is triclinic, probable space groupP1, witha= 16.217(7) Å,b= 42.544(9) Å,c= 8.557(4) Å, α = 95.72(4)°, β = 90.25(4)°, γ = 96.78(4)°,V= 5832(4) Å3,Z= 4.The nine strongest powder-diffraction lines [d(Å) (I/I0) (hkl)] are: 3.927 (100) (10 0); 3.775 (45) (22); 3.685 (45) (60); 3.620 (50) (440); 3.124 (50) (2); 2.929 (60) (42); 2.850 (70) (42); 2.579 (45) (02); 2.097 (60) (024). The mean of 11 electron microprobe analyses gave elemental concentrations as follows: Pb 10.09(1) wt.%, Tl 20.36(1), Sb 23.95(1), As 21.33(8), S 26.16(8), totalling 101.95 wt.%, corresponding to Tl4.15Pb2.03(As11.86Sb8.20)S34. The new mineral is named for Alberto Dal Negro, Professor in Mineralogy and Crystallography at the University of Padova since 1976.

The 1992 Polarized Light Source

2002 ◽  
Author(s):  
R. Alley ◽  
M. Woods ◽  
M. Browne ◽  
J. Frisch ◽  
M. Zolotorev
Keyword(s):  
Light Source ◽  
Polarized Light

Design of light source for ultra-high precision fiber optic gyroscope

2021 ◽  
Author(s):  
Xin Chen ◽  
Miao Yan ◽  
Jie Yu ◽  
Ruoxiang Tang
Keyword(s):  
Light Source ◽  
High Precision ◽  
Fiber Optic ◽  
Fiber Optic Gyroscope

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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