Issue 110 / March - April 2016
Science and Square
1-Hayashi R. et al. Co-ordinated ocular development from human iPS cells and recovery of corneal function. Nature, January 2016.
2-Lin H. et al. Lens regeneration using endogenous stem cells with gain of visual function. Nature, January 2016.
Two exciting new studies demonstrated that cataracts could be cured by using stem-cell-based treatments. In the first study, researchers developed a method to convert induced pluripotent stem (iPS) cells into the discs of multiple eye tissues. Then, they isolated corneal cells from the cultured discs and transplanted them into a rabbit with corneal blindness. This successfully restored the rabbitâ€™s sight. In the second study, instead of the transplantation of new cells, researchers used human patientsâ€™ own stem cells to cure their blindness. This study focused on 37 infants born with cataracts. The standard treatment for cataracts has involved cutting a 6-millimetre slit in the center of the lens capsule, which allows the surgeon to replace the diseased lens with an artificial one. Researchers have developed a new, minimally invasive technique. Surgeons now only open a 1.5-millimetre incision on the side of the lens capsule. Though they remove the diseased lens, they preserve the lensâ€™ epithelial stem cells (LECs) and their natural environment. This promotes dormant LECs to regrow an entirely new lens â€“ one that is capable of vision â€“ in about 3 months. 12 infants went through this surgery and all of them successfully grew new, functional lenses. These children healed much faster compared to the 25 infants who underwent the standard procedure â€“ and most importantly, the former group all ended up with clear, natural lenses. The first infant treated with this method two years ago is reported to still have good vision, and scientists anticipate that the regenerated lenses will grow as the child grows. The immediate success of this study represents a new approach in human-tissue regeneration and in how human diseases can be treated. Even though this kind of approach may not be applicable to adult human patients in the near future (due to the reduced regenerative capacity of LECs in older people), it still holds big promises for the future of eye disorders.
Renewable Plastic From Carbon Dioxide and Plants
1-Banarjee A. et al. Carbon dioxide utilization via carbonate-promoted Câ€“H carboxylation. Nature, January 2016.
Researchers found a novel way to convert carbon dioxide (CO2) and inedible plant material into a low-carbon alternative to petroleum-based plastics. Plastics are typically made from polyethylene terephthalate (PET) and about 50 million tons of PET is produced each year for items such as fabrics, electronics, recyclable beverage containers, and personal-care products. The manufacturing of PET produces substantial amounts of CO2 (four tons of CO2 generated for each ton of PET produced), which contributes to global warming. The more environmentally efficient alternative to PET is polyethylene furandicarboxylate (PEF), which is produced from the combination of ethylene glycol and a compound called 2-5-Furandicarboxylic acid (FDCA). PEF is superior to PET for two reasons: First, FDCA can be sourced from biomasses instead of petroleum. Second, PEF seals out oxygen much more efficiently, which can be useful for bottling applications. Despite the obvious advantages of PEF, the plastics industry has not been able to find a low-cost way to manufacture FDCA, the raw material needed for PEF, at scale. Researchers finally solved this problem by developing an efficient and reliable method to produce FDCA. They simply combined carbonate with CO2 and furoic acid, a derivative of furfural (a compound made from agricultural waste), and then heated the mixture to 200 0C, forming a liquefied salt. After five hours, 89% of the salt mixture had been converted to FDCA. This approach has great potential to reduce greenhouse emissions, because the CO2 required to make PEF could be obtained from fossil-fuel power plant emissions or other industrial sites. In addition, PEF products are completely recyclable, as they can be burned into CO2 that will be utilized by plants, which can then be used to make more PEF.
Magnetic Chips: Computing With One Million Times Less Energy
For the first time, engineers have proved that magnetic chips can function at the lowest fundamental energy dissipation possible under the laws of thermodynamics.
This breakthrough could dramatically reduce the power consumed by modern computers. The research team used an innovative approach to measure the infinitesimal energy dissipation when a nanomagnetic bit was flipped. They used a laser probe to trace the direction of the magnetic field as it was flipped from "up" to "down," or vice versa, when driven by an external magnetic field. They found that only 15 millielectron volts (3 zeptojoules) of energy were sufficient to flip the magnetic bit at room temperature, revealing the minimal amount of energy required for computer operations. This finding raised the possibility of reducing power consumption to as little as one-millionth the amount used per operation by standard transistors in modern computers. Power reduction is important for mobile devices, which require powerful processors with long-lasting and light-weight batteries. It is also a serious problem at the industrial scale. The increase in cloud-computing demands greater electricity for the increasing number of giant cloud data hubs, which have already started to take a toll on the world's electrical grid. The computer technology industry is looking forward to the industrial application of magnetic computer chips in the near future.
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