Week 5 Flashcards
How is surface roughness quantified?
by deviations in the direction of the normal vector of a real surface from it’s ideal form
If deviations are large, the surface is (smooth/rough). In contrast, if deviations are small, the surface is (smooth/rough).
rough
smooth
What is the relevance of roughness?
determines how a real object will interact with its environment
- rough surfaces = weaker
- irregularities = sites for failure
- may promote adhesion with water, microbes and cells
- may influence wettability
What are the roughness parameters?
most common
Rz = distance between highest peak and lowest peak
Ra = average roughness
What are three measures used to determine roughness?
- stylus profilometer
- needle that moves up and down and creates a graph - optical methods
- microscope with layers - AFM (nano-scale)
- similar to stylus but displacement of tip is measured by lasers
How do you modify roughness?
polishing
General processes by which a material’s structure and properties are probed and measured
biomaterials characterization
How are biomaterials characterized?
What are the four considerations for biomaterial characterization?
- length scales (hierarchy)
nano-, micro-, macro- scale - location dependence
which region? - surface only vs. bulk
- environmental effects
highly used to test bonding strength of dental materials
micro-tensile testing
What is micro-indentation?
What is nano-identation?
gained popularity after developing machines that can record small loads and displacements
Compare micro- and nano- indentation
What kind of tools are available?
uses visible light and a system of lenses to magnify images of small objects
light microscope
an optical microscope that uses fluorescence and phosphorescence instead of, or in addition to, reflection and absorption to study properties of organic and inorganic substances
fluorescence microscope
True or false: Fluorescent microscopes only use fluorescent samples in their natural forms.
False.
Samples can be in their natural form or treated with fluorescing molecules
allows us to identify cells and cellular components with a high degree of specificity
fluoresence micoscope
What are the three characteristics of fluorescence?
- identify components with specificity and monitor chemical/biological processes
- degradation of samples by high energy light sources
- improve resolution of an optical microscope
an optical imaging technique for increasing optical resolution and contrast of a microscope image by using a spatial pinhole placed at the confocal plane of the lens to eliminate out-of-foucs light
confocal microscope