Irandaily | No. 4400 | Science

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Building Batteries From Plant Roots

Researchers have found an eco-friendly alternative to the metal ores currently favored in the electrodes of lithium-ion batteries.
The new non-toxic and sustainable battery uses purpurin, a red/yellow dye extracted from the root of the madder plant that has been used for dying cloth for at least 3,500 years--meaning the substance can simply be grown rather than mined, IdeaConnection wrote.
Currently, lithium cobalt oxide (LiCoO2) is the material of choice for forming the cathode in Li-ion batteries. However, mining the cobalt and combining it with lithium at high temperatures to form the cathode is an expensive and energy-intensive process.
Couple this with the energy used to extract the cobalt at the recycling stage and Dr. Arava Leela Mohana Reddy from Rice University says that for every kilowatt-hour of energy in a Li-ion battery, production and recycling pumps an estimated 72 kg (159 lb) of carbon dioxide into the atmosphere.
Dr. Reddy, along with Rice University colleagues and researchers from The City College of New York and the US Army Research Laboratory, found that purpurin and other biologically based color molecules offer great potential as a more environmentally friendly alternative. This is due to the carbonyl and hydroxyl groups in the molecules that are adept at passing electrons back and forth.
“These aromatic systems are electron-rich molecules that easily coordinate with lithium,” explained City College Professor of Chemistry, George John.
Making the purpurin electrode can be done at room temperature in a simple process which involves dissolving the purpurin and adding lithium salt. After the solution turns from reddish yellow to pink, indicating the salt’s lithium ions have bonded with the purpurin, the solvent can be removed and the electrode is ready.
The team claims the purpurin is less complicated to use than the one or two other organic molecules being examined for use in batteries. Additionally, growing madder or other biomass crops would help remove carbon dioxide from the atmosphere. The resulting batteries would also be non-toxic, making them easier to dispose of.

How We See Colors

Scientists have until now not fully understood how animals see in color, since visual pigments in eyes contain exactly the same chromophore (light absorbing segment of the molecule) and yet can absorb different wavelengths of light.
The chromophore retinal (Vitamin A aldehyde or retinaldehyde) is used by all animals but, depending on the photoreceptor proteins (opsins) associated with it, the same molecule can absorb a spectrum of colors from blues or even ultraviolet to reds, Medical Xpress reported.
How a single molecule can do this has until now been uncertain. Now researchers, led by Prof. Babak Borhan of Michigan State University at East Lansing, set out to try to understand the mechanism by which the opsins change the light absorption spectrum of the chromophore retinal.
They concentrated their efforts on a pigment found in human retinal photoreceptor cells, rhodopsin, which consists of opsin and chromophore components. One of the major theories about how retinal works is that because it is strongly positively charged at one end, it could distribute this electrostatic charge across the chromophore molecule and this would enable it to absorb the longer wavelengths at the red end of the spectrum.
Another theory held that a change in shape of the chromophore-opsin complex could alter the absorption capabilities.
“The problem with testing the theories,” Borhan said, “is that the visual pigments have proved difficult to work with.”
So instead, Borhan and colleagues used human cellular retinol binding protein II, (hCRBPII), a gut protein that binds retinol, which is closely related to retinal but which tolerates mutations more readily.
The team first created a mutation of hCRPBII that could bind retinal. They then changed the distribution of the electrostatic charge on the retinal molecule by replacing amino acids at the binding site retinal uses on hCRPBII in various ways, and in so doing created a range of pigment proteins.
The team then used spectrophotometry to compare the light entering and leaving the proteins to determine which wavelengths were being absorbed. Using this approach they were able to prove the charge distribution theory was correct and that no change in shape was necessary.
A byproduct of the new research is the production of the 11 new artificial pigments, which could be used in tracking proteins or cell types being studied, as well as other possible applications such as in food dyes.
One of the new pigments could absorb a red wavelength of 644 nanometers (nm), which is above the theoretical maximum wavelength retinal can absorb (560 nm) and is close to infrared (750 nm +).

Incredible Origami House Can Change Shape

There are houses for cold climates, which are designed to keep in the precious warmth and there are houses for hot climates where architecture allows for air to sweep through and keep inhabitants cool.
However, until now, the two were difficult to combine, Daily Mail reported.
But this new incredible folding house is able to, in the words of its creators, ‘metamorphosize’ into eight different configurations to adapt to seasonal, meteorological and even astronomical conditions.
For example, in the summer plan, bedroom one faces east and watches the sun rise as its inhabitant wakes up. It can then rotate so that the user is constantly in sunlight, while the house generates energy through its solar panels.
The revolutionary home is based on the work of an early 20th-century mathematician who discovered a way to dissect a square and rearrange its parts into an equilateral triangle.
The flexibility of the house allows adaptation from winter to summer and day to night by literally moving inside itself.
Thick heavy external walls unfold into internal walls allowing glass internal walls to become facades; doors can become windows, and vice versa.
The layout consists of two bedrooms, an open-plan living room and a bathroom, but it too can be adapted to suit the needs of different living situations.
The incredible house is the brainchild of British architects David Grunberg and Daniel Woolfson, who launched the D*Haus company to develop the concept.
The shape-shifting home was first conceived as part of Grunberg’s graduation project, for which he designed a house that could withstand the extreme sub-Arctic temperatures in Lap Land, a region infamous for its harsh weather.
The pair’s design, which they call D*Dynamic, is based on the work of English author and mathematician Henry Dudeney, a leading puzzle creator.
In 1903, Dudeney invented a way to cut an equilateral triangle into four pieces that could be rearranged into a square, a conundrum he dubbed the “Haberdasher’s Puzzle”.
The D*Dynamic house realizes this mathematical curiosity as a solution to living in extreme climates. Sections would fold out on rails so interior partitions could become exterior walls in warm weather.
The whole building could even rotate to follow the direction of the Sun throughout the day.
In a press release, D*Haus describe their house, which is yet to be built, as “a product of an applied mathematical realization”.
“The D*Haus Company is set to cause a revolution in architecture and design by transforming Dudeney’s idea from the conceptual, to the physical,” the release adds.
“Inspired by Dudeney’s logic puzzle, each D*Haus dwelling is capable of adapting to changing patterns of living in the future.
“D*Haus is continuing the journey that Dudeney began by breathing new life into a century-old concept; not only to define a space, but a lifestyle.”

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