rod
(noun)
a rod-shaped cell located in the outer retina of the eye that is extremely sensitive to light
Examples of rod in the following topics:
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Mechanical Work and Electrical Energy
- where B is the magnetic field, l is the length of the conducting rod, and v is the (constant) speed of its motion.
- As the rod moves and carries current i, it will feel the Lorentz force
- To keep the rod moving at a constant speed v, we must constantly apply an external force Fext (equal to magnitude of FL and opposite in its direction) to the rod along its motion.
- Since the rod is moving at v, the power P delivered by the external force would be:
- Right hand rule gives the current direction shown, and the polarity of the rod will drive such a current.
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Motional EMF
- Consider the area enclosed by the moving rod, rails and resistor.
- B is perpendicular to this area, and the area is increasing as the rod moves.
- Thus the magnetic flux enclosed by the rails, rod and resistor is increasing.
- Note that the area swept out by the rod is ΔA=ℓx.
- Right hand rule gives the current direction shown, and the polarity of the rod will drive such a current.
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Transduction of Light
- Light is tranduced in rods and cones; visual information is processed in the retina before entering the brain.
- The rods and cones are the site of transduction of light into a neural signal.
- Visual signals leave the cones and rods, travel to the bipolar cells, and then to ganglion cells.
- In the absence of light, the bipolar neurons that connect rods and cones to ganglion cells are continuously and actively inhibited by the rods and cones.
- Human rod cells and the different types of cone cells each have an optimal wavelength.
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The Physical Pendulum
- Recall that a simple pendulum consists of a mass suspended from a massless string or rod on a frictionless pivot.
- In that case, we are able to neglect any effect from the string or rod itself.
- For illustration, let us consider a uniform rigid rod, pivoted from a frame as shown (see ).
- The moment of inertia of the rigid rod about its center is:
- A rigid rod with uniform mass distribution hangs from a pivot point.
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MreB and Determinants of Cell Morphology
- Indeed, recent studies have found that MreB proteins polymerize to form filaments that are similar to actin microfilaments.MreB controls the width of rod-shaped bacteria, such as Escherichia coli.
- A mutant E. coli that creates defective MreB proteins will be spherical instead of rod-like.
- This ability of MreB is because of RodZ, an inner membrane protein containing an 80-residue, N-terminal cytoplasmic region, and a 200-amino acid periplasmic C-terminal tail.
- RodZ co-localizes with MreB helices in a manner that is strictly dependent on its cytoplasmic region.
- MreB- RodZ complexes act as a major stabilizing factor in bacterial cell wall and ensure the insertion of new peptidoglycan in a spiral like fashion into the cell wall.
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Elasticity, Stress, and Strain
- Additionally, the change in length is proportional to the original length L0 and inversely proportional to the cross-sectional area of the wire or rod.
- Tension: The rod is stretched a length ΔL when a force is applied parallel to its length.
- (b) Compression: The same rod is compressed by forces with the same magnitude in the opposite direction.
- For larger deformations, the cross-sectional area changes as the rod is compressed or stretched.
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Anatomy of the Eye
- There are two types of photoreceptors in the retina: rods and cones.
- Rods, strongly photosensitive, are located in the outer edges of the retina.
- In humans, cones far outnumber rods in the fovea.
- Rods and cones are photoreceptors in the retina.
- Rods respond in low light and can detect only shades of gray.
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Vision: The Visual System, the Eye, and Color Vision
- the retina, which allows us to piece images together and includes cones and rods.
- Generally speaking, cones are for color vision and rods are for shadows and light differences.
- This density map shows the retina, which is made up of cones and rods.
- Cones perceive color and rods perceive shadow in images.
- In the fovea, which is responsible for sharp central vision, there is huge density of cones but no rods.
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Noncholera Vibrios
- Vibrio is a Gram-negative bacteria possessing a curved rod shape (comma shape), several species of which can cause foodborne infection.
- Vibrio is a genus of Gram-negative bacteria possessing a curved rod shape (comma shape).
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Cytophaga and Relatives
- Cytophaga are a type of bacteria characterized as Gram-negative, rod shaped bacteria that utilize a gliding mechanism for locomotion.
- Cytophaga represent gram-negative, gliding, rod-shaped bacteria.