SciTech Briefs
Physicists turn to micro-scale engines to bend second law
The second law of thermodynamics states, in the most basic terms, that as energy is transformed or transferred it is increasingly wasted. This law is one of the main impediments to designing efficient technologies; the thermodynamic laws affect everything from cars to batteries.
It has long been a mission of physicists to seek out some way by which this law of wasted energy might be bendable. While physics concerns itself with big-picture concepts, some physicists, such as Janet Anders, of the University of Exeter’s theoretical physics department, are taking a closer look and considering the potential of micro-engines, some potentially composed of only three molecules and powered by a single atom.
Recent experiments to determine whether or not the quantum level is more demanding than the macro-level have found that the second law is actually more demanding at the quantum level. In the words of the English astrophysicist Arthur Eddington, any idea that goes against the law of thermodynamics will only “collapse in deepest humiliation.” While this may be so, physicists refuse to stop trying to break the rules.
Source: Science News
Giant spider-bot unlocks secrets of web-vibration sense
Spiders use vibration sensitivity to determine where in their webs trapped insects are struggling and to quickly meet and consume them. However, the mechanism behind these vibration senses, is unknown. Researchers from Oregon State University attempted to find out more, using a large-scale web structure created out of threaded aluminum to simulate the spider’s web and an eight-legged model in the center which detects the vibrations from the web.
Spider webs use two types of silk in their construction, though there are several other types used for various purposes. The researchers did the same, using both aluminum and elastic rope, attempting to be as true-to-life as possible. Using a large subwoofer, the researchers vibrated areas of the web and recorded the vibrations felt by the centrally located spider.
This experiment found that spiders feel very complex vibration sensations. In some portions of the web, and at some frequencies, the shaking is heavy, while in other areas, it completely disappears. This allows the spider to know which area of the web the struggling insect might be contained in and to quickly respond by devouring the prey before it can escape.
Source: BBC
Metamaterials showcase unique growth properties
Metamaterials are materials that exhibit properties not normally observed in nature. In the case of research performed by Ahmad Rafsanjani, a materials and mechanical engineer from McGill University in Montreal, that means expanding width-wise when stretched, rather than simply becoming thinner and longer.
The properties of these metamaterials allow them to expand in all directions, effectively “unfolding” into larger structures. They are also adjustable, such that they can expand and return to their original geometric formation without much effort. Rafsanjani gleaned his inspiration from Islamic motifs, which he described as a “huge library of geometries.” In order to actually test out these metamaterial concepts, Rafsanjani created two simplified patterns out of laser-cut rubber sheets.
Other more complicated patterns utilize complex origami folding techniques. These types of metamaterials are called auxetic, meaning that they are able to expand in all directions as they are stretched. Potential uses for this technology could be found in solar panels or satellite technology, and depending on how finely tuned one’s laser is, these auxetic materials can likely be scaled to the microscopic level.
Source: BBC
Portugal’s storks cease migration to scavenge landfills
Researchers from the University of East Anglia are concerned with the migratory patterns of Portugal’s white stork population. The birds usually migrate to Africa for its warmer climates but lately, they have been staying in Portugal year-round. Whenever a species’ behavioral patterns change so drastically, it’s often a symptom of deeper issues, including a possible change in the local ecosystem. Strangely, however, the white stork population has been steadily growing for the past few years.
The amount of landfills within the area have also been growing, and these two factors were found to correlate. In an effort to discover why the storks’ behavior had changed, a team of researchers tracked 48 white storks’ movement patterns with GPS monitors. They found that the birds traveled to landfill sites quite often, and that the landfills had been supplying the storks with fatty leftovers year-round.
This is problematic for a number of reasons, but one of them is that the storks frequently ingest smaller, inedible pieces of computers and plastic. In the future, this food supply will be dwindling, as landfill regulations and clean-up efforts mount, so perhaps the storks will learn to migrate once again.
Source: BBC
Reprogrammed human cells regrow corneal tissue
Researchers have recently been able to coax human stem cells to grow into corneal tissue and utilize these to repair rabbit eyes. The cornea is a portion of the eye’s surrounding membrane, located directly in the front of the eye, and it is important for allowing light to enter the eye, and also for focusing a large amount of that light.
The first study, performed by Kohji Nishida, an ophthalmologist at Osaka University, involved growing proto-eyes using reprogrammed human cells. These cells formed an eye-like structure, as expected, and when the researchers isolated cells with potential to become corneal tissue, researchers transplanted them into rabbits with corneal damage, and the cells repaired the damage.
Potential advantages of this technology are tissue repair surgeries, but there may also be advantages beyond surgery as research moves toward tissue self-repair rather than transplantation. One example of this is a study done by Kang Zhang, a stem cell biologist, and his colleagues at the University of California, San Diego, in which researchers tested cataract patients’ eyes and observed that individuals who underwent the surgery were more likely to completely regrow their lenses.
Source: Science News
Stem cells from fat used to create and repair cartilage
While many people would like to get rid of their extra fat, Rocky Tuan, the Director of the Cellular and Molecular Engineering Lab at the University of Pittsburgh, is turning liposuctioned fat into cartilage. Tuan is also using fat cells to grow partial tendons and ligaments to support the joints that this cartilage cushions.
This process is made possible by the high amount of stem cells present in fatty — or adipose — tissue. According to J. Peter Rubin, Chair of Plastic Surgery and Professor of Bioengineering at the University of Pittsburgh, fat cells are so multi-talented that they could be used as a sort of complete body repair kit.
One of the benefits of this type of transmutative process is that excess fat from liposuction surgeries can be put to good use, potentially finding its way into the joints of someone in need. There are also implications for this type of procedure in other areas of plastic surgery. Potentially, a similar process could be used to recreate muscle tissue as well. While there is still progress to be made before researchers completely understand each potential application of fat cells, this research could be an important leap in body repair.
Source: Science News