Comparison of Four Methods for the Determination of Asbestos Fiber Concentrations in Workplace Atmospheres by Phase Contrast Microscopy

1994 ◽  
Vol 9 (10) ◽  
pp. 707-711
Author(s):  
Chantal Dion ◽  
Guy Perrault
Keyword(s):  
Phase Contrast ◽  
Asbestos Fiber ◽  
Phase Contrast Microscopy ◽  
Contrast Microscopy

Increased Fraction of Circulating Activated Platelets in Acute and Previous Cerebrovascular Ischemia

1998 ◽  
Vol 80 (08) ◽  
pp. 298-301 ◽  
Author(s):  
Andreas Ruf ◽  
Axel Vogt ◽  
Christoph Lichy ◽  
Florian Buggle ◽  
Heinrich Patscheke ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Phase Contrast ◽  
Matched Control ◽  
Shape Change ◽  
Antigen Expression ◽  
Phase Contrast Microscopy ◽  
Activated Platelets ◽  
Contrast Microscopy ◽  
Age And Sex

SummaryDetermination of circulating activated platelets may be helpful to estimate the prognosis and to stratify therapies in arterial vascular disorders including stroke. We used flow cytometry and phase contrast microscopy to study whether the fraction of platelets expressing p-selectin and CD63 and the fraction of platelets with shape change are increased in patients with acute and previous cerebrovascular ischemia.The proportion of platelets expressing activation dependent antigens was higher in patients with acute (n = 24; p-selectin: 8.23 ± 4.21%; CD63: 3.53 ± 2.53%) and with previous cerebrovascular ischemia (n = 46; 3.86 ± 1.98%; 2.80 ± 1.79%) as compared to age- and sex-matched control subjects (n = 35; 2.17 ± 0.96%; 1.79 ± 0.75%; p ≤0.005, respectively). In patients with previous ischemia, there was no difference between treatment with aspirin (n = 25) or phenprocoumon (n = 21). Hypertension, diabetes mellitus and smoking were not associated with increased antigen expression (analysis of variance). The fraction of discoid platelets and platelet counts were not significantly different between groups.Our results indicate increased expression of platelet neoantigens in acute and to a less degree in previous cerebrovascular ischemia. Ongoing platelet activation after cerebrovascular ischemia despite therapy with aspirin or phenprocoumon indicates that new anti-platelet drugs may be of benefit for these patients. Flow cytometry appears to be a useful tool to assess platelet function in cerebrovascular ischemia.

Determination of transition curves of high-Tc superconductors by phase contrast microscopy

1995 ◽  
Vol 507 (2) ◽  
pp. 136-143
Author(s):  
Cl. Kriebel ◽  
O. Hoffels ◽  
R. Borowski ◽  
H. Gottschalk ◽  
H. Alexander ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
High Tc Superconductors ◽  
High Tc ◽  
Contrast Microscopy ◽  
Transition Curves

Integral refractive index determination of living suspension cells by multifocus digital holographic phase contrast microscopy

2007 ◽  
Vol 12 (5) ◽  
pp. 054009 ◽  
Author(s):  
Björn Kemper ◽  
Sebastian Kosmeier ◽  
Patrik Langehanenberg ◽  
Gert von Bally ◽  
Ilona Bredebusch ◽  
...  
Keyword(s):  
Refractive Index ◽  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
Suspension Cells ◽  
Contrast Microscopy

Determination of the integral refractive index of cells in suspension by digital holographic phase contrast microscopy

2008 ◽  
Author(s):  
Sebastian Kosmeier ◽  
Björn Kemper ◽  
Patrik Langehanenberg ◽  
Ilona Bredebusch ◽  
Jürgen Schnekenburger ◽  
...  
Keyword(s):  
Refractive Index ◽  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
Contrast Microscopy ◽  
Refractive Index Of Cells

An interferometer microscope

1950 ◽  
Vol 204 (1077) ◽  
pp. 170-187 ◽  
Keyword(s):  
Refractive Index ◽  
Epithelial Cells ◽  
Optical Thickness ◽  
Phase Contrast ◽  
Phase Contrast Microscopy ◽  
Object Plane ◽  
Operational Procedure ◽  
Contrast Microscopy ◽  
New Type

Some of the drawbacks of conventional phase contrast microscopy are enumerated and the desirability of an interferometer microscope is indicated. A number of existing ways of achieving this are described, together with their merits and drawbacks. A new type of interferometer microscope which avoids some of these disadvantages is described, together with its operational procedure. The conditions covering coherence in the object plane are investigated and a simple approximation for evaluating the coherence is derived. An elementary discussion of contrast arising from phase or amplitude objects is given, and a number of experimental results are presented as photo-micrograms. Finally, a method for the accurate measurement of the optical thickness of an object is described, with the results of a determination of the refractive index of the cytoplasm of epithelial cells.

Sign in / Sign up

Export Citation Format

Share Document