Dark-Field Microscopy and Photon Tunneling Microscopy

Author(s):  
Frédärique de Fornel
Author(s):  
J. Langmore ◽  
M. Isaacson ◽  
J. Wall ◽  
A. V. Crewe

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.


Author(s):  
William Krakow

Tilted beam dark-field microscopy has been applied to atomic structure determination in perfect crystals, several synthesized molecules with heavy atcm markers and in the study of displaced atoms in crystals. Interpretation of this information in terms of atom positions and atom correlations is not straightforward. Therefore, calculated dark-field images can be an invaluable aid in image interpretation.


Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3509
Author(s):  
Paule Marcoux-Valiquette ◽  
Cécile Darviot ◽  
Lu Wang ◽  
Andrée-Anne Grosset ◽  
Morteza Hasanzadeh Kafshgari ◽  
...  

Reliable cytopathological diagnosis requires new methods and approaches for the rapid and accurate determination of all cell types. This is especially important when the number of cells is limited, such as in the cytological samples of fine-needle biopsy. Immunoplasmonic-multiplexed- labeling may be one of the emerging solutions to such problems. However, to be accepted and used by the practicing pathologists, new methods must be compatible and complementary with existing cytopathology approaches where counterstaining is central to the correct interpretation of immunolabeling. In addition, the optical detection and imaging setup for immunoplasmonic-multiplexed-labeling must be implemented on the same cytopathological microscope, not interfere with standard H&E imaging, and operate as a second easy-to-use imaging method. In this article, we present multiplex imaging of four types of nanoplasmonic markers on two types of H&E-stained cytological specimens (formalin-fixed paraffin embedded and non-embedded adherent cancer cells) using a specially designed adapter for SI dark-field microscopy. The obtained results confirm the effectiveness of the proposed optical method for quantitative and multiplex identification of various plasmonic NPs, and the possibility of using immunoplasmonic-multiplexed-labeling for cytopathological diagnostics.


Nanoscale ◽  
2021 ◽  
Author(s):  
Paula Zamora-Perez ◽  
Beatriz Pelaz ◽  
Dionysia Tsoutsi ◽  
Mahmoud G. Soliman ◽  
Wolfgang J. Parak ◽  
...  

Hyperspectral-enhanced dark field microscopy to correlate Au/CuS NPs’ changes in their physicochemical properties induced by cellular environments with their functionality as photothermal probes by tracking their scattering profile evolution in real time.


2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Eva Jennische ◽  
Stefan Lange ◽  
Ragnar Hultborn

A simple dark field microscopy technique was used for visualization of blood vessels in normal human renal tissues and carcinoma. Phase contrast condenser ring apt for high power objectives was combined with a 10x objective in order to create a dark field illumination of the specimens examined. The endothelial lining of the vessels had been stained by using CD31 monoclonal antibodies combined with conventional peroxidase immunohistochemistry. The final DAB addition used for this technique induced an intense light scatter in the dark field microscope. This scattered light originating from the endothelial lining made the walls of the bright vessels easily detectable from the dark background.


2007 ◽  
Vol 64 (5) ◽  
pp. 313-318 ◽  
Author(s):  
Milena Krstic ◽  
Novica Stajkovic

Background/Aim. Lyme disease (LD) is a cosmopolitan disease from the group of zoonoses that in humans can affect skins, joints, heart and/or nervous system. Research conducted in endemic areas, shows not only that the population, which lives or works in tick habitats, is in a high risk for getting infected by LD cause, but also that every enviroment itself is specific in regard to both vectors and B. burgdorferi species. In our enviroment, research of seropositivity to B. burgdorferi in persons exposed to vectors of LD have not been conducted. The aim of this study was to determine whether there was a higher risk for getting B. burgdorferi infection in the fieldworks of JKP "Zelenilo Beograd" than in other persons. Methods. Risk for getting LD in the fieldworkers of JKP "Zelenilo Beograd" (park-maintanance company) was determined according to seropositivity, the number and infection rate of LD vectors, and entomological risk index (ERI) value. Serum samples of 34 fieldworkers of JKP "Zelenilo Beograd", and 35 persons of the control group, were tested for the presence of specific IgM and IgG anti-B. burgdorferi antibodies by using ELISA test. In the research localities, the number of ticks was estimated by using the flag hours method, and tick infection rate was determined by dark field microscopy, with magnification rate of 400?. The data were analyzed statistically using ?2 test, and Pearson's correlation analysis. Results. Out of 34 fieldworkes serum samples, 8 (23.5%) were positive on anti-B. burgdorferi antibody presence, while in the control group only one (2.9%) sample was positive (p < 0,05). Seropositivity rate varied from 0-66.6% among localities. Flag hours value among the localities ranged from 8.2-29.9, and tick infection rate ranged from 10.8- 22.3%. ERI value was 0.03-0.15. Correlation between flag hour rate and seropositivity, tick infection rate and seropositivity, and also ERI and seropositivity was established. Conclusion. Frequency of B. burgdorferi seropositivity was significantly higher in green-surface maintenance workers, than in the control group not exposed to these habitats. A significant correlation was found between anti-B. burgdorferi antibodies findings and the number of ticks, tick infection rate, and ERI. The results obtained in our study indicate that there was a significantly higher risk for getting LD cause in the fieldworkers than in the control group. .


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