mucholderthen:

Illustration
the visible spectrum as part of the electromagnetic spectrum
(Credit:  Abrisa Glass & Coatings, 2005)

X-rays, light, and radio waves are examples of electromagnetic waves.

Light is what we call the part of the electromagnetic spectrum that we can detect with our eyes. The cone photoreceptors in our eyes have evolved so that they are most sensitive at different regions of the visible spectrum. This forms the basis for our sensation of color 

At the blue end of the visible spectrum, the wavelength of light is shorter — about 400 nanometers.

A nanometer is 1 billionth of a meter, or 1 × 10−9 meter.  The abbreviation for nanometer is ‘nm’.

At the red end of the spectrum, the wavelength of light is longer — about 700 nm.

Cone photoreceptors have evolved into three different types. Each one is most sensitive to a different region of the visible spectrum. One type responds best to shorter wavelengths; another responds best to wavelengths towards the middle of the spectrum; and the third type responds best to longer wavelengths.

The different cone photoreceptors are not sharply tuned to a particular color, however. So a short-wavelength cone photoreceptor can still respond to longer-wavelength light that falls on it. It is more likely to respond to shorter wavelength light, but it is still possible for it to respond to mid- and long-wavelength light.

The signals from the three different types of cones are combined in the retina and in the brain, eventually giving rise to the sensation of color.

[ via Mixing Light ]

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thefrogman:

Drawn by Mike Jacobsen [website | twitter | store]

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quantumaniac:

Amazing Everyday Objects Seen by a Scanning Electron Microscope

These amazing images are from the book Microcosmos by Brandon Brill, in which a scanning electron microscope takes images of common everyday objects. Above, from left to right, we see: 

• An ant holding a microchip. 
• Eyelash hairs growing from skin.
• The surface of a strawberry.
• Velcro. 
• Household dust, including: cat fur, twisted synthetic and woolen fibers, serrated insect scales, a pollen grain, plant and insect remains.
• A razor blade.
• Rusty metal nail. 
• Mushroom spores. 

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parlanceofafrail:

Phagocytosis


Specialized immune cells such as macrophages internalize and destroy bacteria to fight infections. This process, called phagocytosis is a key part of the innate mammalian immune system.

When an invading bacterium binds to the membrane of a macrophage, the cell membrane starts to wrap around the invader and internalizes the pathogen. This process was so far mainly investigated by conventional light and electron microscopy, which provide primarily kinematic and structural information. However, the mechanical properties of this process, described by the physical forces and energies involved are still barely known.

We investigate the mechanics of the phagocytic machinery by using optical tweezers in combination with live cell microscopy. We found that filopodia, thin spike-like cell protrusions act as cellular tentacles during phagocytosis: a few seconds after binding to a particle, filopodia retract and pull the bound particle toward the cell. This retraction is f-actin dependent and has a mean step size of 36 nm. The force-velocity relationship of this filopodial retraction is in agreement with the kinetics of an ensemble of multiple motors.

[Source]

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scipsy:

Detail of a pod of flowering legume Scorpius muricatus. Stereomicroscopy, darkfield illumination. Viktor Sýkora, Hyskov, Czech Republic.

More of this: 20 Award-Winning Microscope Images

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fuckyeahelectronmicroscope:

Baby Bee (Larvae) 

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scinerds:

E. coli is capable of producing a diesel substitute

 Strains of E. coli bacteria are capable of producing a biofuel almost identical to diesel.

The importance of the discovery hinges around the idea of “drop-in” fuels — that existing technology which runs on diesel would not need to be modified in order to utilize the biofuel meaning the costs to business of switching energy sources would be minimal.

“Producing a commercial biofuel that can be used without needing to modify vehicles has been the goal of this project from the outset,” said Professor John Love from the University of Exeter’s Biosciences department.

“Replacing conventional diesel with a carbon neutral biofuel in commercial volumes would be a tremendous step towards meeting our target of an 80 percent reduction in greenhouse gas emissions by 2050. Global demand for energy is rising and a fuel that is independent of both global oil price fluctuations and political instability is an increasingly attractive prospect.”

The E. coli uses a natural oil production process to convert sugars into fats which are then used in the bacteria’s cell membrane. By genetically altering the E. coli the researchers were able to convert the sugars to the imitation fossil fuel (perhaps faux-sil fuel?) instead.

Unfortunately the process only yields tiny amounts of biodiesel at present meaning that before we can switch energy sources bioscientists will need to find a way to refine the process and produce industrial quantities of fuel.

The team at the University of Exeter received support for their project from multinational oil company, Shell. According to Rob Lee from Shell projects & technology: “While the technology still faces several hurdles to commercialisation, by exploring this new method of creating biofuel, along with other intelligent technologies, we hope they could help us to meet the challenges of limiting the rise in carbon dioxide emissions while responding to the growing global requirement for transport fuel.”

Francis Crick, writing in Nature (April 26, 1974) on the 21st birthday of the original Nature paper (April 25, 1953) proposing the Watson-Crick structure of DNA

21st Birthday Rites for Double Helix

Chemical & Engineering News, May 27, 1974

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thebrainscoop:

The Field Museum - Gorilla gorilla

Look forward to small photosets of my trip behind the scenes at the Chicago Field Museum in the coming days!  There were so many remarkable things, it’d be rude not to share. 

We came across this specimen in the mammal prep lab waiting to be reunited with the rest of its skeleton, presumably still being processed in their dermestid colony.  It’s the spinal column of a gorilla (Gorilla gorilla) that was donated by the Lincoln Park Zoo once the animal died.  

What is absolutely jaw-droppingly fascinating about this specimen is that the entire spinal column is fused.  All of the vertebrae have grown together to form one continuous, smooth bone, rather than being comprised of multiple moving vertebrae.  There is also a large healing pathology towards the top of the lumbar vertebrae and at the bottom of the thoracic.  An obvious reason for this to have occurred is because this animal had a limited range of movement as it lived in a zoo enclosure for the majority, if not duration of its life.  

It makes me wonder what human skeletons must look like if we continue to live our lives in front of computers, heavily restricting our range of movement day-in and day-out. 

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scienceyoucanlove:

A tough exterior

By Fernán Federici and Jim Haseloff, University of Cambridge

Although what leaps to mind when we think of tree bark may be only the brittle and rough outermost layer, in fact bark can consist of complex layers of different cell types and tissues, including cork, phelloderm, cortex and phloem. Similar in many ways to the function of our skin, bark protects the tree from damage, such as from insects or dehydration, and some types of trees are even able to repair physical damage to the bark. Such wound repair is provided by callus, a mass of cells that provides regenerative potential.

Image: Confocal image of Drimys winteri bark cells. Sample fixed, cleared, and stained by Cambridge University Plant Teaching lab.

It’s sad that I remember all of this from bio 1

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