Pratique du Shadowing: Introduction to focused ion beam scanning electron microscopy (FIB-SEM) - Apprendre l'anglais à l'oral avec YouTube

C2
Hi, I'm Kedar Narayan, a group leader at the Center for Molecular Microscopy, or CMM, at the National Cancer Institute and Frederick National Laboratory for Cancer Research.
⏸ En pause
29 phrases
Si les phrases sont trop courtes ou trop longues, cliquez sur Edit pour les ajuster.
1
Hi, I'm Kedar Narayan, a group leader at the Center for Molecular Microscopy, or CMM, at the National Cancer Institute and Frederick National Laboratory for Cancer Research.
2
Imaging three-dimensional objects in 2D can be limiting, yielding an incomplete or even a misleading picture.
3
And so, at the CMM, we apply cutting-edge electron microscopy, or EM, technologies to image biological samples at the highest possible resolutions.
4
My group specializes in the imaging of cells and tissues, that is, larger volumes, in 3D and at nanoscale resolutions.
5
In this short video, I'm going to give you a flavor of an imaging technique that we employ in our lab, Focused Ion Beam Scanning Electron Microscopy, or FibSem.
6
FibSem, as you will see, is a powerful 3D-EM imaging approach, and in this specific example, we highlight a correlative light microscopy and FibSem, or CLEM-FibSem workflow.
7
CLEM-FibSem combines the advantages of light and electron microscopy to generate image reconstructions of targeted features of interest in 3D at resolutions of tens of nanometers.
8
So here you have a group of cells of which a subset is fluorescently labeled.
9
These cells are grown on a gridded cover slip, a glass substrate on which an alphanumeric code has been etched.
10
You can now image these cells either live or after fixation using fluorescence microscopy and also record their x-y coordinates using the gridded pattern.
11
Once this step is completed, the cells can be fixed, stained, dehydrated, and resin-embedded in situ.
12
When the gridded coverslip is removed, the alphanumeric pattern is transferred to the resin surface in relief, with the cells embedded just beneath that surface.
13
In other words, you now know exactly where to find your cells of interest.
14
At this point, the cell sample is transferred to the FibSem instrument.
15
This Martian looking surface is a close up of the resin where you expect to find your targeted cell.
16
The resin embedded cell is protected by a patterned platinum and carbon pad deposited by the focused ion beam or fib, which appears as a rapidly moving blue beam in this movie.
17
Remarkably, the same focused ion beam that deposits the platinum and carbon pad can now be used to mill a trench in front of the targeted cell.
18
The tightly controlled fib inches towards the cell, ablating away the resin, and eventually reveals the cell itself in cross-section.
19
The scanning electron imaging beam, shown here as a yellow band, now rasters over the polished resin surface, and a detector records a high-resolution backscatter electron signal.
20
This process is repeated over and over.
21
As the fib moves forward and mills away a few more nanometers of the resin, the SEM images the newly exposed section of the cell to generate the next image, and so on and so on.
22
Typically, we generate SEM images at 3 to 5 nanometer pixel size in the imaging plane, and 3 to 15 nanometer fib step size, meaning that this automated loop is often repeated several thousand times to generate a highly information-rich ultra-structural image stack covering entire mammalian cells.
23
These images are then registered using the notch marks in the pad and converted to an isotropic image volume that allows you to visualize architectural features throughout the bulk of the cell sample.
24
The final step is segmentation.
25
Here we show the extraction and rendering of the plasma membrane of the cell.
26
Fibsem imaging reveals that the membrane extensions in the cell that looked like spaghetti in 2D cross-section are actually veils when visualized in three dimensions.
27
FibSem imaging can be applied to a wide variety of systems to confirm observations, generate hypotheses, and most fun of all, make unexpected discoveries in cell biology.
28
If you'd like to know more, you can contact me, Kedhar Narayan, at the Center for Molecular Microscopy at the National Cancer Institute and Frederick National Laboratory for Cancer Research.
29
You can also visit cmm.nci.nih.gov.

Télécharger l'application

Everything you need to speak fluently

AI PronunciationScore every sentence
IPA PracticeMaster every sound
VocabularyBuild your word bank
Vocab GameLearn while playing
Scanner pour télécharger
Scanner pour télécharger
Download on theApp Store
Get it onGoogle Play

Why practice speaking with this video?

Practicing speaking with the video "Introduction to focused ion beam scanning electron microscopy (FIB-SEM)" can greatly benefit English learners who wish to enhance their technical vocabulary and articulation skills in scientific contexts. By engaging with this video, you immerse yourself in a specialized linguistic environment, focusing on advanced English terminology related to microscopy and cell biology. This not only improves your vocabulary but also boosts your confidence in discussing complex topics.

Additionally, this video provides an excellent opportunity to practice shadowing, a technique where you mimic the speaker's intonation, rhythm, and pronunciation. Utilizing a shadowing site allows learners to repeat phrases after the speaker, enhancing verbal fluency and comprehension. When you learn English with YouTube videos like this, you practice not just words, but also the art of conveying complex ideas clearly and effectively.

Grammar & Expressions in Context

In this video, several key structures are notable:

  • Present Continuous Tense: For instance, the speaker uses phrases like "we are applying cutting-edge electron microscopy," which illustrates ongoing actions and research activities.
  • Passive Voice: The use of the passive form, such as "the cells are embedded," shifts focus onto the process rather than the performer of the action, which is common in scientific communication.
  • Conditional Structures: Expressions like "if you'd like to know more" open up conversational avenues, inviting further engagement and interaction.
  • Technical Vocabulary: Words specific to the field, such as "correlative light microscopy" and "isotropic image volume," become essential for those interested in scientific discussions and communication.

Common Pronunciation Traps

Certain words and phrases from the video may be challenging to pronounce. Here are a few examples:

  • “Microscopy”: The irregular stress patterns can be tricky; focus on separating the syllables appropriately.
  • “Ablating”: This word can be difficult for non-native speakers; ensure you practice the pronunciation frequently to improve your clarity.
  • “Ultra-structural”: This multi-syllabic term may lead to mispronunciation because of its complexity.

By taking the time to practice these words and phrases, learners can significantly improve English pronunciation and speak more fluently about intricate subjects. Engaging with material like this through shadow speak techniques enables you to integrate pronunciation practice with practical learning in a fun and interactive way.

Qu'est-ce que la technique du Shadowing ?

Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.

☕ Offrez-nous un café