[3dem] Two questions about vitrification

[Farzad]

Dear Colleagues,

I have two questions about some weird effects I see in some of my samples
that I cannot explain properly. I would appreciate it if you could help me
understand it properly:


1- In some samples (occasionally) the holes appear darker than the carbon.
Does anyone have any idea why this happens? I uploaded two images next to
this email to show what I mean. In thicker regions, the hole appears dark,
and in thinner ones, it starts to show a brighter region in the center. Can
it be due to a high concentration of scattering points (e.g. small
molecules or too much concentration etc.)? Or it is something else, like
simply the thickness effect? How can I overcome it? Any suggestion would be
highly appreciated!

2- Recently I am seeing "crystalline ice" in the thinner parts of some
samples, i.e. the place it is blotted and entered first in the water. In
the thicker regions, the crystalline ice disappears and naturally, in the
very thick area, the crystallinity reappears. The buffer is TRIS+NaCl. Can
it be due to local evaporation of the buffer in the thinner regions and
local increase in the concentration and reduction of the melting point? Or
any fluid dynamic effect which reduces the cooling rate? Any idea?

Thanks a lot for your answers to any of these questions in advance.

Farzad Hamdi, Dr.-Ing
Scientist,
Kastritis Laboratory for Biomolecular Research
Interdisciplinary research center HALOmem,
Institute of Biochemistry and Biotechnology, Biocenter,
Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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 hole_type_Thick_dark.jpg
<https://urldefense.com/v3/__https://drive.google.com/file/d/154v7jylS4uNLFU6LEYfLHgiP-uIwM4ve/view?usp=drive_web__;!!Mih3wA!HoqrY5ETlqfP2IM4GpD5vW_BbvFd6hoOGOSQ9-2Br6THfsCNGc06BIoIRb77AkDgr5lM59PM8-nnGqpAPQ$ >
 hole_type_Thin_light.jpg
<https://urldefense.com/v3/__https://drive.google.com/file/d/1nH_oxJnH7kSJMNPXEzkoggVhe8sRmGVn/view?usp=drive_web__;!!Mih3wA!HoqrY5ETlqfP2IM4GpD5vW_BbvFd6hoOGOSQ9-2Br6THfsCNGc06BIoIRb77AkDgr5lM59PM8-nCtYn5KQ$ >
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