Notes in Lecture 8

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Status	Last Update	Fields
Published	10/21/2024	A TEM operates under a high vacuum about {{c1::10^-10}} atmosphere
Published	10/21/2024	{{c1::Traditional EM}}fixstaindehydratethin sectioningimagingor negative staining
Published	10/21/2024	{{c1::CryoEM}}cryofix image
Published	10/21/2024	Cryo-EMobserve specimen embedded in vitrified ice at {{c1::cryogenic}} temperatureuse {{c1::low}} dose electron beam to minimize sample damage cl…
Published	10/21/2024	liquid and the particles in the holes are held by {{c2::surface tension}} --> flash cooled in liquid {{c1::ethane}}
Published	10/21/2024	Cryo fixation mostly is {{c1::plunge freezing }}
Published	10/21/2024	Cryo-EM uses {{c1::high pressure}} freezing for {{c2::thick}} specimens
Published	10/21/2024	An {{c1::EM image}} is the 2D projection of a 3D object
Published	10/21/2024	How do we get the 3D structure? {{c1::AVERAGING}}
Published	10/21/2024	Snintillatorlight generated by {{c2::electron}} activates neighboring pixels toocascading on fiber optics ({{c2::delocalization}} of signal)slow integ…
Published	10/21/2024	DEDeach {{c1::pixel}} is a detectorno {{c1::cascading}}fast detection (can do {{c2::movies}} instead of {{c2::single image}})
Published	10/21/2024	The {{c1::carbon}} support film {{c3::deforms}} as electron beam {{c2::illuminates}} the sample
Published	10/21/2024	{{c1::Cryo-electron microscopy}}use a transmission electron microscope recorded images of frozen hydrated specimenthere is no need to crystallize…
Published	10/21/2024	EM lens is quite literally {{c1::coiled wires}}
Published	10/21/2024	Electron microscope at an accelerarting voltage of {{c1::75kV}} would have wavelength < {{c2::5 picometers}}
Published	10/21/2024	The {{c1::short}} wavelength allows high resolution imaging
Published	10/21/2024	Challenges in EM for bioligcal samplessample needs to be in {{c1::high vaccum}}severe radiation damage limits {{c1::allowed electron dose}}radiation i…
Published	10/21/2024	Achieving {{c1::sub-nm resolutions}} has been difficult for biological samples until very recently
Published	10/21/2024	{{c1::Heavy metal salts}} form a stable, electron rich "mold" around the biological specimen of interest
Published	10/21/2024	negative stainingsample shape is {{c1::perserved}} in vacuumgreat {{c1::contrast-enhancement}}resolution is {{c1::compromised}}
Published	10/21/2024	problems{{c1::high vaccuum}} = structures modify{{c1::e- damaging}}: must limit e- dose{{c1::radiation}}: induced motions
Published	10/21/2024	{{c1::negative staining with a heave metal}}: covers and makes a mold and see the "shadow" of the protein
Published	10/21/2024	the metal covering is whay compromises the {{c1::resolution}}, but is high {{c1::contrast}}
Published	10/21/2024	{{c1::Pleomorphic}}: doesn't have a regular shape
Published	10/21/2024	Cryo is an alternative - much easiernot as much {{c1::contrast}}preserves {{c1::details}} better
Published	10/21/2024	CryoEM is better for {{c1::native}} conditions
Published	10/21/2024	even if {{c1::vitrification}}, ice crystals will form
Published	10/21/2024	gets rid of {{c1::noise}} through {{c2::computational}} methods
Published	10/21/2024	liquid {{c1::N2}} not good enough, too slow thermal transfer
Published	10/21/2024	high pressure freezing{{c1::thicker}} specimenssmall organismstissuesuse a {{c1::cryoFIB}} or {{c1::microtome}} to make thick
Published	10/21/2024	{{c1::EM image}} is the 2D projection of a 3D object
Published	10/21/2024	{{c1::Indirect e- detectors}}photons can scatter excitationcascading effects - transmitting delocation of signalslow and blurry
Published	10/21/2024	{{c1::direct e- detectors}}takes care of all the problems from indrect e- detectors
Status	Last Update	Fields