Polysulfone Dental Device Remedies Teeth Grinding Problem

For people who are suffering from a tendency to grind their teeth while asleep, Michigan-based Grind Guard Technologies together with injection molder Maple Valley Plastics, has introduced ‘GrindGuardN’ a safe medical device for the mouth. A 3-mm-high central power bar is positioned at the middle of the mouth guard that directs pressure on the upper and lower teeth, and is said to reduce the biting and clenching intensity by up to 60%.

The transparent injection molded 0.2-mm-thick outer shell of this dental device is made of Udel® P-1700 polysulfone (PSU) resin from Solvay Advanced Polymers, which is insert molded with a polycaprolactone (PCL) thermoplastic. To customize the GrindGuardN according to your mouth, it can be placed in a microwaved water for 90-120 seconds at 130°F (54.44°C). The white colored polycaprolactone turns transparent which signifies that it is soft enough to fit easily in synchronization with the front teeth. Polycaprolactone doesn’t deform or melt even at temperature up to 171°F (77.22°C). GrindGuardN, has received clearance from the U.S. Food & Drug Administration.

Researchers Train Bacteria to Convert High Percentage of Bio-wastes into Plastic

TU Delft Researcher Jean-Paul Meijnen has 'trained' bacteria to convert all the main sugars in vegetable, fruit and garden waste efficiently into high-quality environmentally friendly products such as bioplastics. There is considerable interest in bioplastics nowadays. The technical problems associated with turning potato peel into sunglasses, or cane sugar into car bumpers, have already been solved. The current methods, however, are not very efficient: only a small percentage of the sugars can be converted into valuable products. By adapting the eating pattern of bacteria and subsequently training them, Meijnen has succeeded in converting sugars into processable materials, so that no bio-waste is wasted.

Basis for bioplastics

The favored raw materials for such processes are biological wastes left over from food production. Lignocellulose, the complex combination of lignin and cellulose present in the stalks and leaves of plants that gives them their rigidity, is such a material. Hydrolysis of lignocellulose breaks down the long sugar chains that form the backbone of this material, releasing the individual sugar molecules. These sugar molecules can be further processed by bacteria and other micro-organisms to form chemicals that can be used as the basis for bioplastics. The fruit of the plant, such as maize, can be consumed as food, while the unused waste such as lignocellulose forms the raw material for bioplastics.

Cutting the price of the process

"Unfortunately, the production of plastics from bio-wastes is still quite an expensive process, because the waste material is not fully utilized," explains Jean-Paul Meijnen. (It should be noted here that we are talking about agricultural bio-wastes in this context, not the garden waste recycled by households.) The pre-treatment of these bio-wastes leads to the production of various types of sugars such as glucose, xylose and arabinose. These three together make up about eighty per cent of the sugars in bio-waste.

The problem is that the bacteria Meijnen was working with, Pseudomonas putida S12, can only digest glucose but not xylose or arabinose. As a result, a quarter of the eighty per cent remains unused. "A logical way of reducing the cost price of bioplastics is thus to 'teach' the bacteria to digest xylose and arabinose too."

Enzymes

The xylose has to be 'prepared' before Pseudomonas putida S12 can digest it. This is done with the aid of certain enzymes. The bacteria are genetically modified by inserting specific DNA fragments in the cell; this enables them to produce enzymes that assist in the conversion of xylose into a molecule that the bacteria can deal with.

Meijnen achieved this by introducing two genes from another bacterium (E. coli) which code for two enzymes that enable xylose to be converted in a two-stage process into a molecule that P. putida S12 can digest.

Evolution

This method did work, but not very efficiently: only twenty per cent of the xylose present was digested. The modified bacteria were therefore 'trained' to digest more xylose. Meijnen did this by subjecting the bacteria to an evolutionary process, successively selecting the bacteria that showed the best performance.

"After three months of this improvement process, the bacteria could quickly digest all the xylose present in the medium. And surprisingly enough, these trained bacteria could also digest arabinose, and were thus capable of dealing with the three principal sugars in bio-wastes." Meijnen also incorporated other genes, from the bacterium Caulobacter crescentus. This procedure also proved effective and efficient from the start.

Blend

Finally, in a separate project Meijnen succeeded in modifying a strain of Pseudomonas putida S12 that had previously been modified to produce para-hydroxybenzoate (pHB), a member of the class of chemicals known as parabens that are widely used as preservatives in the cosmetics and pharmaceutical industries.

Meijnen tested the ability of these bacteria to produce pHB, a biochemical substance, from xylose and from other sources such as glucose and glycerol. He summarized his results as follows: "This strategy also proved successful, allowing us to make biochemical substances such as pHB from glucose, glycerol and xylose. In fact, the use of mixtures of glucose and xylose, or glycerol and xylose, gives better pHB production than the use of unmixed starting materials. This means that giving the bacteria pretreated bio-wastes as starting material stimulates them to make even more pHB."

Scientists Manipulate Plant Metabolism to Produce Potential Precursor to Raw Material for Plastics

In a pioneering step toward achieving industrial-scale green production, scientists from the U.S. Department of Energy's (DOE) Brookhaven National Laboratory and collaborators at Dow AgroSciences report engineering a plant that produces industrially relevant levels of compounds that could potentially be used to make plastics. The research is reported in Plant Physiology.

"We've engineered a new metabolic pathway in plants for producing a kind of fatty acid that could be used as a source of precursors to chemical building blocks for making plastics such as polyethylene," said Brookhaven Biochemist John Shanklin, who led the research. "The raw materials for most precursors currently come from petroleum or coal-derived synthetic gas. Our new way of providing a feedstock sourced from fatty acids in plant seeds would be renewable and sustainable indefinitely. Additional technology to efficiently convert the plant fatty acids into chemical building blocks is needed, but our research shows that high levels of the appropriate feedstock can be made in plants."

The method builds on Shanklin's longstanding interest in fatty acids - the building blocks for plant oils - and the enzymes that control their production. Discovery of the genes that code for the enzymes responsible for so called "unusual" plant oil production encouraged many researchers to explore ways of expressing these genes and producing certain desired oils in various plants.

"There are plants that naturally produce the desired fatty acids, called 'omega-7 fatty acids,' in their seeds - for example, cat's claw vine and milkweed - but their yields and growth characteristics are not suitable for commercial production," Shanklin said. Initial attempts to express the relevant genes in more suitable plant species resulted in much lower levels of the desired oils than are produced in plants from which the genes were isolated. "This suggests that other metabolic modifications might be necessary to increase the accumulation of the desired plant seed oils," Shanklin said.

"To overcome the problem of poor accumulation, we performed a series of systematic metabolic engineering experiments to optimize the accumulation of omega-7 fatty acids in transgenic plants," Shanklin said. For these proof-of-principle experiments, the scientists worked with Arabidopsis, a common laboratory plant.

Enzymes that make the unusual fatty acids are variants of enzymes called "desaturases," which remove specific hydrogen atoms from fatty acid chains to form carbon-carbon double bonds, thus desaturating the fatty acid. First the researchers identified naturally occurring variant desaturases with desired specificities, but they worked poorly when introduced into Arabidopsis. They next engineered a laboratory-derived variant of a natural plant enzyme that worked faster and with greater specificity than the natural enzymes, which increased the accumulation of the desired fatty acid from less than 2 percent to around 14 percent.

Though an improvement, that level was still insufficient for industrial-scale production. The scientists then assessed a number of additional modifications to the plant's metabolic pathways. For example, they "down-regulated" genes that compete for the introduced enzyme's fatty acid substrate. They also introduced desaturases capable of intercepting substrate that had escaped the first desaturase enzyme as it progressed through the oil-accumulation pathway. In many of these experiments they observed more of the desired product accumulating. Having tested various traits individually, the scientists then combined the most promising traits into a single new plant.

The result was an accumulation of the desired omega-7 fatty acid at levels of about 71 percent in the best-engineered line of Arabidopsis. This was much higher than the omega-7 fatty acid levels in milkweed, and equivalent to those seen in cat's claw vine. Growth and development of the engineered Arabidopsis plants was unaffected by the genetic modifications and accumulation of omega-7 fatty acid.

"This proof-of-principle experiment is a successful demonstration of a general strategy for metabolically engineering the sustainable production of omega-7 fatty acids as an industrial feedstock source from plants," Shanklin said.

This general approach - identifying and expressing natural or synthetic enzymes, quantifying incremental improvements resulting from additional genetic/metabolic modifications, and "stacking" of traits - may also be fruitful for improving production of a wide range of other unusual fatty acids in plant seeds.

This research was funded by the DOE Office Science, and by The Dow Chemical Company and Dow AgroSciences.

LCA by Toyota Tsusho & Braskem Concludes that Green Polyethylene can Reduce GHG Emission

Braskem S.A. and Toyota Tsusho Corporation (Toyota Tsusho) have concluded the joint study of life cycle analysis for polyethylene derived from Brazilian sugarcane (Green Polyethylene), and has found that the Green Polyethylene emits less greenhouse gas (GHG) when compared to petroleum-based polyethylene even if it is delivered to the other side of the earth.

The University of Tokyo, Tokyo, Japan conducted the analysis under the collaborative study with the parties using the preliminary eco-efficiency study performed by Fundação Espaço Eco in Brazil (2007/2008), which shows that 1 kilogram of Green Polyethylene emits 1.35 kilograms* of CO₂ equivalents of GHG when it is produced in Brazil, shipped to Japan, used by consumer as container and packaging, and then incinerated. Meanwhile, traditional petroleum-based polyethylene emits 4.55 to 5.10 kilograms in its overall life cycle. As a result, the study demonstrates that 70 to 74 percent of GHG can be reduced with the substitution of Green Polyethylene for traditional polyethylene.

For details of the study, Professor Masahiko Hirao and Assistant Professor Yasunori Kikuchi of the university will deliver a presentation at "International Congress on Sustainability Science and Engineering - ICOSSE11", the most renowned environmental congress held in Tucson, AZ, USA, on January 11, 2011.

Earlier this year, Braskem inaugurated the largest industrial-scale plant of bio-based ethylene with an annual production capacity of 200,000 tons to be converted into the same volume of Green Polyethylene. Toyota Tsusho will start distribution of Green Polyethylene in Asian countries including Japan after certain shipping time from Brazil to the countries.

Nobel Laureates from Manchester University Give Graphene a Teflon Makeover

Professor Andre Geim, who along with his colleague Professor Kostya Novoselov won the 2010 Nobel Prize for graphene - the world's thinnest material, has now modified it to make fluorographene - a one-molecule-thick material chemically similar to Teflon.

Fluorographene is fully-fluorinated graphene and is basically a two-dimensional version of Teflon, showing similar properties including chemical inertness and thermal stability. The results have been reported in the advanced online issue of the journal Small. The work is a large international effort and involved research groups from China, the Netherlands, Poland and Russia.

The team hopes that fluorographene, which is a flat, crystal version of Teflon and is mechanically as strong as graphene, could be used as a thinner, lighter version of Teflon, but could also be in electronics, such as for new types of LED devices.

Graphene, a one-atom-thick material that demonstrates a huge range of unusual and unique properties, has been at the centre of attention since groundbreaking research carried out at The University of Manchester six years ago. Its potential is almost endless - from ultrafast transistors just one atom thick to sensors that can detect just a single molecule of a toxic gas and even to replace carbon fibers in high performance materials that are used to build aircraft.

Professor Geim and his team have exploited a new perspective on graphene by considering it as a gigantic molecule that, like any other molecule, can be modified in chemical reactions. Teflon is a fully-fluorinated chain of carbon atoms. These long molecules bound together make the polymer material that is used in a variety of applications including non-sticky cooking pans.

To get fluorographene, the Manchester researchers first obtained graphene as individual crystals and then fluorinated it by using atomic fluorine. To demonstrate that it is possible to obtain fluorographene in industrial quantities, the researchers also fluorinated graphene powder and obtained fluorographene paper.

Fluorographene turned out to be a high-quality insulator which does not react with other chemicals and can sustain high temperatures even in air. One of the most intense directions in graphene research has been to open a gap in graphene's electronic spectrum, that is, to make a semiconductor out of metallic graphene. This should allow many applications in electronics. Fluorographene is found to be a wide gap semiconductor and is optically transparent for visible light, unlike graphene that is a semimetal.

Professor Geim said: "Electronic quality of fluorographene has to be improved before speaking about applications in electronics but other applications are there up for grabs."

Rahul Nair, who led this research for the last two years and is a PhD student working with Professor Geim, added: "Properties of fluorographene are remarkably similar to those of Teflon but this is not a plastic. "It is essentially a perfect one-molecule-thick crystal and, similar to its parent, fluorographene is also mechanically strong. This makes a big difference for possible applications.

"We plan to use fluorographene as an ultra-thin tunnel barrier for development of light-emitting devices and diodes. "More mundane uses can be everywhere Teflon is currently used, as an ultra-thin protective coating, or as a filler for composite materials if one needs to retain the mechanical strength of graphene but avoid any electrical conductivity or optical opacity of a composite".

Industrial scale production of fluorographene is not seen as a problem as it would involve following the same steps as mass production of graphene.

The Manchester researchers believe that the next important step is to make proof-of-concept devices and demonstrate various applications of fluorographene.

Professor Geim added: "There is no point in using it just as a substitute for Teflon. The mix of the incredible properties of graphene and Teflon is so inviting that you do not need to stretch your imagination to think of applications for the two-dimensional Teflon. The challenge is to exploit this uniqueness."

First turnkey CNG truck upfitted with vacuum body

Developed in collaboration with Vac-Con, the Freightliner Business Class M2 112V compressed natural gas unit will also be equipped with a CNG-powered auxiliary-mounted engine that powers the truck’s water system. Vac-Con provides combination sewer cleaners to municipal and private markets throughout the world.

Its combination cleaners combine high-pressure water and vacuum systems to effectively clean both sanitary and storm drainage infrastructure. Vac-Con tapped Freightliner Trucks to develop the CNG truck based on its ability to fulfill its unique specs and need for a turnkey chassis solution.

"There’s a tremendous green movement happening now, and our customers are looking to us to provide efficient products with alternative fuel options," said Tom Jody, marketing manager for Vac-Con. "From the beginning, the team at Freightliner Trucks had a genuine interest in this concept, and in its success.

" The truck will include an Allison 3000RDS transmission for optimum performance and efficiency, which include patented torque converter technology that results in improved startability at the launch of the vehicle, full power shifts, and a better performing engine. "The CNG project was truly a partnership and we look forward to continuing our work with Freightliner to further refine this and other natural gas products," Jody added. Freightliner Trucks is a division of Daimler Trucks North America LLC, headquartered in Portland, Oregon.

Thermoplastic Robot Suit Makes Aged Body Movement Easy

For the healthcare segment, especially for aging population, and additionally for industries for disaster control, Bayer MaterialScience has introduced Robot Suit ® HAL® (Hybrid Assistive Limb®) that gives support to the human motor in the form of an exoskeleton. Japan-based CyberDyne developed and manufactured this suit which was displayed at K 2010 recently. The white plastic housing of the suit is based on Bayblend®, a thermoplastic polymer blend from Bayer. Robot Suit® HAL® is strapped on to human limbs and controlled via a computer that receives bioelectric signals from electrodes attached to the user’s skin. On the event of movement, nerve signals reach muscles, moving the muscoskeletal system consequently. Based on the signals obtained, the power unit moves the joints in synchronization with the limbs.