S U G A R

S U G A R

WHAT A UNIQUE WAY TO PRESENT THIS...
Someone ought to get an award for this. We know the facts, but this brings it into perspective quickly, doesn???t it?

                                                        Each cube is a teaspoonful.??

From now on it's strawberries, carrots, Cheerios, Special K and corn for me! 

Now they need to do this for salt... 
'When someone shares something of value with you that your health can benefit from, it would show you care if you share it with others.'

Birds

Design Rules Will Enable Scientists to Use DNA to Build Nanomaterials With Desired Properties

Abstract rendering of a DNA strand. (Credit: iStockphoto/Johan Swanepoel)

Science Daily  — Nature is a master builder. Using a bottom-up approach, nature takes tiny atoms and, through chemical bonding, makes crystalline materials, like diamonds, silicon and even table salt. In all of them, the properties of the crystals depend upon the type and arrangement of atoms within the crystalline lattice.

Using nanoparticles as "atoms" and DNA as "bonds," the scientists have learned how to create crystals with the particles arranged in the same types of atomic lattice configurations as some found in nature, but they also have built completely new structures that have no naturally occurring mineral counterpart.

Now, a team of Northwestern University scientists has learned how to top nature by building crystalline materials from nanoparticles and DNA, the same material that defines the genetic code for all living organisms.

The basic design rules the Northwestern scientists have established for this approach to nanoparticle assembly promise the possibility of creating a variety of new materials that could be useful in catalysis, electronics, optics, biomedicine and energy generation, storage and conversion technologies.

The new method and design rules for making crystalline materials from nanostructures and DNA will be published Oct. 14 by the journal Science.

"We are building a new periodic table of sorts," said Professor Chad A. Mirkin, who led the research. "Using these new design rules and nanoparticles as 'artificial atoms,' we have developed modes of controlled crystallization that are, in many respects, more powerful than the way nature and chemists make crystalline materials from atoms. By controlling the size, shape, type and location of nanoparticles within a given lattice, we can make completely new materials and arrangements of particles, not just what nature dictates."

Mirkin is the George B. Rathmann Professor of Chemistry in the Weinberg College of Arts and Sciences and professor of medicine, chemical and biological engineering, biomedical engineering and materials science and engineering and director of Northwestern's International Institute for Nanotechnology (IIN).

"Once we have a certain type of lattice," Mirkin said, "the particles can be moved closer together or farther apart by changing the length of the interconnecting DNA, thereby providing near-infinite tunability."

"This work resulted from an interdisciplinary collaboration that coupled synthetic chemistry with theoretical model building," said coauthor George C. Schatz, a theoretician and the Charles E. and Emma H. Morrison Professor of Chemistry at Northwestern. "It was the back and forth between synthesis and theory that was crucial to the development of the design rules. Collaboration is a special aspect of research at Northwestern, and it worked very effectively for this project."

In the study, the researchers start with two solutions of nanoparticles coated with single-stranded DNA. They then add DNA strands that bind to these DNA-functionalized particles, which then present a large number of DNA "sticky ends" at a controlled distance from the particle surface; these sticky ends then bind to the sticky ends of adjacent particles, forming a macroscopic arrangement of nanoparticles.

Different crystal structures are achieved by using different combinations of nanoparticles (with varying sizes) and DNA linker strands (with controllable lengths). After a process of mixing and heating, the assembled particles transition from an initially disordered state to one where every particle is precisely located according to a crystal lattice structure. The process is analogous to how ordered atomic crystals are formed.

The researchers report six design rules that can be used to predict the relative stability of different structures for a given set of nanoparticle sizes and DNA lengths. In the paper, they use these rules to prepare 41 different crystal structures with nine distinct crystal symmetries. However, the design rules outline a strategy to independently adjust each of the relevant crystallographic parameters, including particle size (varied from 5 to 60 nanometers), crystal symmetry and lattice parameters (which can range from 20 to 150 nanometers). This means that these 41 crystals are just a small example of the near infinite number of lattices that could be created using different nanoparticles and DNA strands.

Mirkin and his team used gold nanoparticles in their work but note that their method also can be applied to nanoparticles of other chemical compositions. Both the type of nanoparticle assembled and the symmetry of the assembled structure contribute to the properties of a lattice, making this method an ideal means to create materials with predictable and controllable physical properties.

Mirkin believes that, one day soon, software will be created that allows scientists to pick the particle and DNA pairs required to make almost any structure on demand.

The Air Force Office of Scientific Research, the U.S. Department of Energy Office of Basic Energy Sciences and the National Science Foundation supported the research.

Depressed kids dig heavy metal

THE UNIVERSITY OF MELBOURNE

"Young people at risk of depression are more likely to be listening to music, particularly heavy metal music, in a negative way." Image: podgorsek/iStockphoto Young people at risk of depression are more likely to listen habitually and repetitively to heavy metal music. University of Melbourne researcher Dr Katrina McFerran has found. A senior lecturer in Music Therapy at the Melbourne Conservatorium of Music, Dr McFerran is immersed in a new study that aims to find out why some young people use heavy metal music in a negative way. By conducting in-depth interviews with 50 young people aged between 13 and 18, along with a national survey of 1000 young people, Dr McFerran is looking to develop an early intervention model that can be integrated into schools to impact positively before behavioral problems occur. “The mp3 revolution means that young people are accessing music more than ever before and it’s not uncommon for some to listen to music for seven or eight hours a day,” she said. “Most young people listen to a range of music in positive ways; to block out crowds, to lift their mood or to give them energy when exercising, but young people at risk of depression are more likely to be listening to music, particularly heavy metal music, in a negative way. “Examples of this are when someone listens to the same song or album of heavy metal music over and over again and doesn’t listen to anything else. They do this to isolate themselves or escape from reality. “If this behavior continues over a period of time then it might indicate that this young person is suffering from depression or anxiety, and at worst, might suggest suicidal tendencies.” Dr McFerran said parents should be aware of their children’s music listening habits, pick up on early warning signs and take early action. “If parents are worried, they should ask their children questions like – how does that music make you feel? If children say the music reflects or mirrors the way they feel then ask more about what the music is saying,” she said. “If listening doesn’t make them feel good about themselves, this should ring alarm bells. Alternatively, if parents notice a downturn in their child’s mood after listening to music this is also a cause for showing interest and getting involved.” As part of her study Dr McFerran is seeking input from young people, particularly those who suffer from depression and anxiety to better understand the affects of heavy metal.  She is also interested in hearing from parents along with their teenagers. Editor's Note: Original news release can be found here.

Brain tumour culprit pinned

THE UNIVERSITY OF NEW SOUTH WALES

Image: adventtr/iStockphoto Australian scientists have played a key role in the identification of a new biochemical mechanism that allows brain tumours to survive and grow, offering hope of new drug treatments for some of the most aggressive tumours.  The discovery offers new therapeutic perspectives and gives hope for the treatment of gliomas, the most common and aggressive type of brain tumour in both adults and children. Gliomas progress rapidly and the median survival time of patients is less than a year. The research – by an international team from Germany, USA, Switzerland and Australia, led by Professor Michael Platten from the Department of Neurooncology at the University Hospital of Heidelberg – was recently published in the prestigious journal Nature.  In the study, the international team – including University of New South Wales researcher Associate Professor Gilles Guillemin – identified the key role played by kynurenine, a by-product of the metabolism of the essential amino acid tryptophan, in favouring brain tumour growth and at the same time suppressing anti-tumour immune response.  The researchers were also able to identify the receptor expressed by tumour cells that kynurenine acts through – the aryl hydrocarbon receptor (AhR).  While particularly relevant in the development and persistence of gliomas, the kynurenine pathway also has a role in other brain cancers, and is implicated in other neurodegenerative diseases. Associate Professor Guillemin said the breakthrough could potentially lead to viable therapeutics for a range of conditions, including Alzheimer’s disease, motor neuron diseases, multiple sclerosis and Parkinson’s disease. “We are currently looking at all the molecules deriving from the tryptophan metabolism through the kynurenine pathway that can be linked to tumour persistence and immune suppression,” said Associate Professor Guillemin, who is head of the Neuroinflammation Group in UNSW’s School of Medical Sciences.  An oral drug able to block enzymes leading to kynurenine production has been developed and the drug could potentially be available for clinical trials within a few years, Associate Professor Guillemin said. The survival time for patients with gliomas, particularly the more aggressive tumours such as glioblastoma multiforme, has not changed in decades despite changes in therapeutic approaches. The mechanism elucidated here offers an entirely novel approach to therapy. The finding is the latest in a series of related breakthroughs. In 2007, Associate Professor Guillemin, UNSW conjoint Professor Bruce Brew (St Vincent’s Hospital) and colleagues showed that tryptophan metabolism was significantly altered in another type of human brain tumour, neuroblastoma. This was a seminal study in the area and served as the foundation for further work. Since then the team, including PhD candidate Ms Seray Adams and postdoctoral scientist Dr Alban Bessede, has worked with neurosurgeon and UNSW conjoint Associate Professor Charlie Teo.  Dr Teo, who provided tumour samples to the researchers and funding through his charity Cure for Life Foundation, said the UNSW researchers could be on the brink of “an enormously powerful discovery”. “The stage is set to apply this discovery to the uniformly fatal disease of brain cancer and in so doing, potentially find an effective treatment,” he said. “Basic science breakthroughs such as this should give comfort to all those affected by brain tumours and confidence to those who have supported the Cure for Life foundation that their hard-earned dollars are being well spent." Editor's Note: Original news release can be found here.