Ancient red dye powers new ‘green’ battery

A natural plant dye once prized throughout the Old World to make fiery red textiles – has found a second life as the basis for a new “green” battery. Chemists from The City College of New York teamed with researchers from Rice University and the U.S. Army Research Laboratory to develop a non-toxic and sustainable lithium-ion battery powered by purpurin, a dye extracted from the roots of the madder plant.

“Purpurin,” on the other hand, said team member and City College Professor of Chemistry George John, “comes from nature and it will go back to nature.” The team reports their results in the journal Nature’s online and open access publication, Scientific Reports, on December 11, 2012.

Most Li-ion batteries today rely on finite supplies of mined metal ores, such as cobalt. “Thirty percent of globally produced cobalt is fed into battery technology,” noted Dr. Leela Reddy, lead author and a research scientist in Professor Ajayan’s lab in the Department of Mechanical Engineering and Material Science at Rice University. The cobalt salt and lithium are combined at high temperatures to make a battery’s cathode, the electrode through which the electric current flows.

Fortunately, biologically based color molecules, like purpurin and its relatives, seem pre-adapted to act as a battery’s electrode. In the case of purpurin, the molecule’s six-membered (aromatic) rings are festooned with carbonyl and hydroxyl groups adept at passing electrons back and forth, just as traditional electrodes do. “These aromatic systems are electron-rich molecules that easily coordinate with lithium,” explained Professor John.

Moreover, growing madder or other biomass crops to make batteries would soak up carbon dioxide and eliminate the disposal problem – without its toxic components, a lithium-ion battery could be thrown away. Best of all, purpurin also turns out to be a no-fuss ingredient. “In the literature there are one or two other natural organic molecules in development for batteries, but the process to make them is much more tedious and complicated,” noted Professor John.

Made and stored at room temperature, the purpurin electrode is made in just a few easy steps: dissolve the purpurin in an alcohol solvent and add lithium salt. When the salt’s lithium ion binds with purpurin the solution turns from reddish yellow to pink. “The chemistry is quite simple,” coauthor and City College postdoctoral researcher Dr. Nagarajan explained.

The team estimates that a commercial green Li-ion battery may be only a few years away, counting the time needed to ramp up purpurin’s efficiency or hunt down and synthesize similar molecules. “We can say it is definitely going to happen, and sometime soon, because in this case we are fully aware of the mechanism,” said Professor John.

Onion Can Soak Up Heavy Metal

Onion and garlic waste from the food industry could be used to mop up hazardous heavy metals, including arsenic, cadmium, iron, lead, mercury and tin in contaminated materials, according to a research paper published in the International Journal of Environment and Pollution.

Biotechnologists Rahul Negi, Gouri Satpathy, Yogesh Tyagi and Rajinder Gupta of the GGS Indraprastha University in Delhi, India, explain how waste from the processing and canning of onion (Allium cepa L.) and garlic (Allium sativum L.) could be used as an alternative remediation material for removing toxic elements from contaminated materials including industrial effluent. The team has studies the influence of acidity or alkalinity, contact time, temperature and concentration of the different materials present to optimize conditions for making a biological heavy metal filter for industrial-scale decontamination.

They have found that at 50 Celsius (122 Fahrenheit), the efficiency of the clean-up process is largely dependent on pH (acidity or alkalinity) and equilibration time usually occurs within half an hour; a pH of 5 was optimal. They demonstrated the maximum extraction was achievable for lead, one of the most troublesome metallic environmental pollutants. They could extract more than 10 milligrams per gram of Allium material from a test solution containing 5 grams per liter of mixed metal ion solution, amounting to recovery efficiency of more than 70%. The absorbed metals can be released into a collecting vessel using nitric acid(HNO3, the CAS number is 7697-37-2) and the biomass reused.

The team experimented with Allium biomass to demonstrated effective removal of heavy metals from both simulated and actual industrial effluents. “The technique appears to be industrially applicable and viable,” they suggest. “This may provide an affordable, environmental friendly and low maintenance technology for small and medium scale industries in developing countries,” they conclude.

New Drug Cuts Risk of Deadly Transplant Side Effect in Half

A new class of drugs reduced the risk of patients contracting a serious and often deadly side effect of lifesaving bone marrow transplant treatments, according to a study from researchers at the University of Michigan Comprehensive Cancer Center.

The study, the first to test this treatment in people, combined the drug vorinostat with standard medications given after transplant, resulting in 21 percent of patients developing graft-vs.-host disease compared to 42 percent of patients who typically develop this condition with standard medications alone.

“Graft-vs.-host disease is the most serious complication from transplant that limits our ability to offer it more broadly. Current prevention strategies have remained mostly unchanged over the past 20 years. This study has us cautiously excited that there may be a potential new way to prevent this condition,” says lead study author Sung Choi, M.D., assistant professor of pediatrics at the U-M Medical School.

Vorinostat is currently approved by the U.S. Food and Drug Administration to treat certain types of cancer. But U-M researchers, led by senior study author Pavan Reddy, M.D., found in laboratory studies that the drug had anti-inflammatory effects as well — which they hypothesized could be useful in preventing graft-vs.-host disease, a condition in which the new donor cells begin attacking other cells in the patient’s body.

The researchers found vorinostat was safe and tolerable to give to this vulnerable population, with manageable side effects. In addition, rates of patient death and cancer relapse among the study participants were similar to historical averages.
The results mirror those found in the laboratory using mice. Reddy, an associate professor of internal medicine at the U-M Medical School, has been studying this approach in the lab for eight years.

“This is an entirely new approach to preventing graft-vs.-host disease,” Choi says. Specifically, vorinostat targets histone deacetylases, which are different from the usual molecules targeted by traditional treatments.

Vorinostat has a dual effect as an anti-cancer and an anti-inflammatory agent. That’s what’s potentially great about using it to prevent graft-vs.-host, because it may also help prevent the leukemia from returning,” Choi says.

The study is continuing to enroll participants. The researchers hope next to test vorinostat in patients receiving a transplant from an unrelated donor, which carries an even greater risk of graft-vs.-host disease. This approach is not currently available outside of this clinical trial.

The structure of vetiver odorants

Approximately one third of all fragrances on the market contain vetiver oil as a key ingredient, for which no synthetic odorant is commercially available. Instead it has to be distilled from the dried roots of vetiver grass.

To find out about the structural requirements of vetiver odorants, researchers in Switzerland devised a synthesis to a 7,8-seco-khusimone, which still contained all the structural features held responsible for the vetiver odour. As they report in the European Journal of Organic Chemistry, however, the final product displayed none of the expected olfactory characteristics, thus proving the vetiver rule wrong.

Vetiver oil has a distinct and characteristic suave and sweet woody-earthy odour with additional green grapefruit and rhubarb-type facets. In perfumery it is often used to provide the woody base note in combination with rather inexpensive bergamot oil, or its synthetic counterparts, which provides a fresh citrus component. Currently, there is no synthetic vetiver perfumery material available commercially. This lack of availability is partially due to the complex sesquiterpene nature of its constituents, and partially due to the lack of consensus as to which constituents contribute to its characteristic odour. One component for which there is consensus is (–)-khusimone, which forms only up to 2% of the essential oil, but does present a typical vetiver odour and is, so far, the only genuine natural lead structure.

Syntheses of related structures led to the development of a vetiver rule, which postulates that the woody odour of vetiver is a result of the presence of an alpha-branched carbonyl osmophore at a specific distance from a bulky group, with an overall dimension of 13–15 carbon atoms. Philip Kraft and Natacha Denizot (Givaudan, Switzerland) thus decided to apply this vetiver rule to the genuine lead structure khusimone itself in order to design a new vetiver odorant with even improved olfactory properties, and in addition an easier synthetic access. The target structure, 7,8-seco-khusimone, was obtained as a mixture of diastereomers in a 10-step sequence starting from commercially available allyl alcohol(the CAS No. is 107-18-6) and isovaleric acid.

A key advantage of the sequence is that it fairly easily allows further modifications of the target structure. Although the desired compound was synthesised successfully it was 10 times less intense than (–)-khusimone and displayed a floral, rosy, green, germanium-like odour with no woody or vetiver character. Kraft and Denizot, therefore, conclude that the vetiver rule has been proved wrong, or at least that the structural requirements are more complex than first suggested.

Gluten Free and Tasty!

Cereals are good for you, supplying the body with carbohydrates, proteins and vitamins. Yet some people are intolerant to the gluten protein they contain. Now, researchers are developing new recipes for tasty, gluten-free pasta and pastries.

Not every person can eat what they like; far from it, one in every 250 people in Germany is intolerant to the protein gluten, which is chiefly found in the cereals wheat, spelt, barley and rye. Experts call this intolerance coeliac disease. For those affected, this means giving up bread, pizza, pasta and cakes, while ice cream wafers, dumplings and pretzels also pass onto the list of banned foods. Those suffering from coeliac disease, a chronic bowel disorder, must keep to a strict diet if they are to avoid diarrhea, stomach ache, vomiting and other symptoms. Accordingly, only gluten-free products make it onto the menu.

Indeed, demand for these food products, mainly offered by small and medium-sized enterprises (SMEs), has risen steadily over the past years. Nevertheless, many consumers dislike gluten-free pasta and bakery products because they are unappetizing, lacking in texture and leave a disagreeable sensation in the mouth. This is a view confirmed in consumer tests involving coeliac disease sufferers and healthy volunteers. Partners include ingredient providers and food producers as well as research institutes from Germany, Ireland, Italy and Sweden. The aim of the project is to enable SMEs to develop premium, tasty gluten-free products that the consumer will eat with real enjoyment and satisfaction. The focus is primarily on bread and pasta, and on improving their taste, smell, appearance, texture and sensation in the mouth.

Gluten is good for baking because it holds the dough together. Hydrocolloids like xanthan gum, HPMC(the full name is Hydroxypropyl methyl cellulose and CAS No. is 9004-65-3) and dextran have all been examined carefully, as well as seeds taken from cereals and pseudocereals like amaranth, quinoa and buckwheat. In addition, scientists analyzed protein isolates taken from potatoes and pulses like lupins, broad beans and peas, as well as investigating the interaction of a variety of recipe ingredients during the production process, and the ways in which this affected texture, sensory properties and aroma profile. A whole range of recipes were tested; for example, researchers combined proteins with soluble fibers like xanthan gum and HPMC or with insoluble citrus fibers.

Bez considers the project a success, pointing to project partners’ success in producing a range of new and improved gluten-free breads, including toast bread, leavened bread and oat wholemeal bread, ciabatta, baguettes and pizza dough. Four of the baked goods producers involved in the project are already using the recipes for ciabatta, wholemeal bread and pizza dough. Furthermore, researchers were able to produce tasty, gluten-free spaghetti with a high fiber and protein content. Bez is confident that it won’t be long now before we see some of the new products lining bakery and supermarket shelves.

Drinkers Should Keep Bag-in-box Wine Cool

Bag-in-box wines are more likely than their bottled counterparts to develop unpleasant flavors, aromas and colors when stored at warm temperatures, a new study has found. Published in ACS’ Journal of Agricultural and Food Chemistry, it emphasizes the importance of storing these popular, economical vintages at cool temperatures.

Helene Hopfer and colleagues explain that compounds in wine react with oxygen in the air to change the way wine looks, tastes and smells. These reactions speed up with increasing temperature. Many winemakers are moving away from the traditional packaging for wine—glass bottles sealed with a natural cork stopper—and trying synthetic corks, screw caps or wine in a plastic bag inside a cardboard box. The scientists wanted to find out how this transition might affect the taste and aroma of wine under different storage conditions.

Californian Chardonnay was stored in five different wine-packaging configurations at three different temperatures for a period of 3 months to study the combined packaging and temperature effects on the sensory and chemical properties of the wines. A trained descriptive panel evaluated aroma, taste, mouthfeel, and color attributes, and the sensory results were correlated to physical and chemical measurements including volatile compounds, SO2, titratable and volatile acidity, oxygen consumption, and wine color, using partial least squares regression.

In general, increased storage temperatures induced the largest changes in the wines; however, significant packaging–temperature effects were found for some attributes as well. Particularly wines stored in bag-in-boxes at 40 °C showed significant increases in oxidized and vinegar aromas and yellow color. Volatile esters also decreased in these wines, while increased levels of compounds generally associated with age- or heat-affected wine were found including 1,1,6-trimethyl-1,2-dihydronaphthalene and furfuryl ether, consistent with previously reported chemical aging reactions. In summary, storing unoaked Chardonnay in different packages significantly changes the sensory and chemical properties depending on the storage temperature. After a storage period of 3 months, bottle storage with various closures changed the wine in a different way than bag-in-box storage.

Using chemical analysis and a panel of trained tasters, the authors studied how storage at various temperatures affected unoaked California Chardonnay stored for three months in different wine packaging types: natural and synthetic corks, screw caps and two kinds of bag-in-box containers. Storage temperature had the biggest impact on all of the wines. Bag wine stored at 68 and 104 degrees Fahrenheit aged significantly faster than the bottled counterparts, becoming darker and developing vinegar notes. All the wines they tested aged better when stored at 50 degrees F.

New Way to Protect Historic Limestone Buildings

Buildings and statues constructed of limestone can be protected from pollution by applying a thin, single layer of a water-resistant coating.

That’s the word from a University of Iowa researcher and her colleagues from Cardiff University in a paper published in the journal Scientific Reports, from the publishers of Nature. In the study, the researchers report a new way to minimize chemical reactions that cause buildings to deteriorate, according to Vicki Grassian, F. Wendell Miller professor in the UI departments of chemistry and chemical and biochemical engineering.

The coating includes a mixture of fatty acids derived from olive oil and fluorinated substances that increase limestone’s resistance to pollution.

“This paper demonstrates that buildings and statues made out of limestone can be protected from degradation by atmospheric corrosion, such as corrosion due to pollutant molecules and particulate matter in air, by applying a thin, one-layer coating of a hydrophobic coating,” she says. “We showed in particular that the degradation of limestone from reaction with sulfur dioxide and sulfate particles could be minimized with an application of this coating.”

One of the buildings the researchers chose for their study was York Minster, a cathedral located in York, England, and one of the largest structures of its kind in northern Europe. Construction of the current cathedral began in the 1260s, and it was completed and consecrated in 1472.

Grassian says York Minster was a perfect structure to study because its limestone surface has been exposed for decades to acid rain, sulfur dioxide and other pollutants. She notes other historic limestone structures could benefit from the coating, including many in the United States.

She notes other attempts have been made to protect existing stonework in cultural heritage sites; however, those coatings(olive oil and fluorinated substances) block the stone microstructure and prevent the edifice from “breathing,” thus creating mold and salt buildup.

Grassian, along with fellow authors Gayan Rubasinghege and Jonas Baltrusatis of the UI chemistry department, have been studying for years reactions of atmospheric gases with minerals such as limestone. In earlier studies, they have shown through detailed analysis that sulfur dioxide could easily degrade limestone and that this degradation reaction was enhanced in the presence of relative humidity.

How do light sticks work?

If you go on a camping vacation, do pack some light sticks in your kit. They are useful for getting some light without electricity or matches. And they come in lots of colours.

Apart from camping, light sticks are used in many other places. Scuba divers use them to look at corals reefs. They are waterproof, need no electricity or fuel, and do not produce heat. After a hurricane, earthquake or fire, it’s dangerous to switch on a light as there may be short circuits. It’s better to use a light stick then.

They are also very popular as decorations in pubs and discos. Smaller versions of them are used to make crazy jewellery like light earrings, light bracelets, light necklaces, as dancing props, and for making Star Wars type lighted swords.

Glowsticking is a form of dance in which the dancer uses one or more coloured glowsticks. They trace out interesting patterns in the air, like the one in the picture.

So how do they work? Light sticks are based on a simple chemical reaction. The most common reaction is hydrogen peroxide and phenol oxalate ester. The hydrogen peroxide is kept in a thin walled glass tube within the light stick, while the ester is outside it. When you tap or bend the light stick, the glass vial breaks. The peroxide is released into the ester.

First, the peroxide reacts with it to form a peroxyacid ester. This isn’t very stable, so it decomposes further, releasing a lot of energy in the process. This energy is absorbed by a fluorescent dye that is coated on the inner wall of the stick. The dye then releases light. The colour of the light depends on the colour of the dye. Rhodamine B gives a red light, while rubrene gives a yellow light.

Wondered how a firefly gives light as it flies through the evening air? A similar reaction happens in its body. An enzyme called luciferase oxidizes a chemical called luciferin. Light is released during this process. Fireflies use light to tell each other where they are. Female fireflies look like worms, so they are called glowworms. They cannot fly.

Many creatures that live deep in the sea, like squids and anglerfish also produce light. The anglerfish produces light at the tip of a long spine that grows from its head. This light attracts prey which the fish quickly gobbles up!

Waste rubber can be converted into quality products

Pioneering new research is set to upset the standard paradigm of downcycling, and as a result, high-quality new plastics from old plastics will soon be a possibility. This breakthrough is made possible thanks to a new kind of material: an environmentally friendly material mix called EPMT. This research team now hopes to upgrade this waste transformation, and has already entered talks with private enterprises to bring their innovation to commercial fruition.

Every year around the world, up to 22 million tonnes of rubber are processed, and a large portion of these goes into the production of vehicle tires. Once the products reach the end of their useful life, they typically land up in the incinerator. In a best-case scenario, the waste rubber is recycled into secondary products. Ground to powder, the rubber residues can be found, for example, in the floor coverings used at sports arenas and playgrounds, and in doormats. But until now, the appropriate techniques for producing high-quality materials from these recyclables did not exist.

Researchers at the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT in Oberhausen have now succeeded in optimising the recycling of rubber waste materials. They have developed a material that can be processed into high-quality products, like wheel and splashguard covers, handles, knobs and steerable castors.

Their breakthrough has already garnered commercial interest. In the ‘Re-use a Shoe’ project, sports gear maker Nike has been collecting used sneakers for some time. The soles of these old sneakers are recycled under the label ‘Nike Grind’ and are reprocessed as filler material for sports arenas and running track surfaces.

The ‘EPMT compound is an innovative breakthrough in more ways than one. The crushing of rubber waste is more environmentally friendly and resource-efficient than producing new thermoplastic rubber products – an important aspect in view of the rising costs of energy and raw materials. ‘EPMT may contain up to 80 per cent residual rubber; only 20 per cent is made up by the thermoplastics,’ says Wack. EPMT can be easily processed in injection mouldings and extrusion machines, and in turn, these products are themselves recyclable.

Altogether, three basic recipes have been developed that collectively can be processed on the large technical production machines. The researchers are capable of producing 100 kilograms to 350 kilograms of EPMT per hour. Spurred on by this success, Wack and his colleagues have founded Ruhr Compounds GmbH. In addition to the production and the sale of EPMT materials, this Fraunhofer commercial spin-off offers custom-made service packages: ‘We determine which of the customer’s materials can be replaced by EPMT, develop customised recipes and also take into account the settings required at our customers’ industrial facilities,’ says the scientist. 

Darker and heavier bottles can protect the quality of white wine

The research conducted at the National Wine and Grape Industry Centre (NWGIC) at Charles Sturt University (CSU), in collaboration with Dr Daniel Dias at The University of Melbourne, examined the impact of light on the quality of white wine, with the ultimate aim to improve its shelf life.

Lead researcher, Dr Andrew Clark said, “A series of experiments dating back to 2008 have attempted to better understand the impact of light on several white wine components that have previously not been investigated. The components were tartaric acid, which is a major organic acid in wine, and iron, a metal ion found at low concentrations in all wines.

“Although not well understood in wine, these same agents were in fact used as photographic emulsions by the pioneers of photography in the mid-1800s.

“We have shown that a chemical process, known as iron (III) tartrate photochemistry, can adversely affect white wine as it may consume wine preservatives and eventually lead to a brown colour. Ultra-violet light as well as blue and green visible light can induce the photochemical process in white wine.

“Darker coloured wine bottles with a thicker wall of glass were found to offer increased protection from this photochemical process.

“These darker and thicker bottles absorb more light so less reaches the wine wine and the extent of detrimental iron tartrate photochemistry is limited. The darker green and amber coloured bottles were particularly useful to absorb the active wavelengths of incident light.

“Wine is mostly exposed to light after bottling and during storage in retail outlets or in the home. Furthermore, wines designed to be stored for longer periods before being drunk are also more likely to have increased light exposure depending on their conditions of storage.

Further studies into the impact of light exposure on wine are currently being carried out by CSU PhD student Ms Paris Grant-Preece at the NWGIC.

A full NWGIC fact sheet on the study, Iron tartrate as a potential precursor of light-induced oxidative degradation of white wine: studies in a model wine system can be found here.