PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Movement of pyrrole molecules defy 'classical' physics

2013-04-26
(Press-News.org) New research shows that movement of the ring-like molecule pyrrole over a metal surface runs counter to the centuries-old laws of 'classical' physics that govern our everyday world.

Using uniquely sensitive experimental techniques, scientists have found that laws of quantum physics - believed primarily to influence at only sub-atomic levels – can actually impact on a molecular level.

Researchers at Cambridge's Chemistry Department and Cavendish Laboratory say they have evidence that, in the case of pyrrole, quantum laws affecting the internal motions of the molecule change the "very nature of the energy landscape" – making this 'quantum motion' essential to understanding the distribution of the whole molecule.

The study, a collaboration between scientists from Cambridge and Rutgers universities, appeared in the German chemistry journal Angewandte Chemie earlier this month.

A pyrrole molecule's centre consists of a "flat pentagram" of five atoms, four carbon and one nitrogen. Each of these atoms has an additional hydrogen atom attached, sticking out like spokes.

Following experiments performed by Barbara Lechner at the Cavendish Laboratory to determine the energy required for movement of pyrrole across a copper surface, the team discovered a discrepancy that led them down a 'quantum' road to an unusual discovery.

In previous work on simpler molecules, the scientists were able to accurately calculate the 'activation barrier' – the energy required to loosen a molecule's bond to a surface, allowing movement – using 'density functional theory', a method that treats the electrons which bind the atoms according to quantum mechanics but, crucially, deals with atomic nuclei using a 'classical' physics approach.

Surprisingly, with pyrrole the predicted 'activation barriers' were way out, with calculations "less than a third of the measured value". After much head scratching, puzzled scientists turned to a purely quantum phenomenon called 'zero-point energy'.

In classical physics, an object losing energy can continue to do so until it can be thought of as sitting perfectly still. In the quantum world, this is never the case: everything always retains some form of residual – even undetectable – energy, known as 'zero-point energy'.

While 'zero-point energy' is well known to be associated with motion of the atoms contained in molecules, it was previously believed that such tiny amounts of energy simply don't affect the molecule as a whole to any measurable extent, unless the molecule broke apart.

But now, the researchers have discovered that the "quantum nature" of the molecule's internal motion actually does affect the molecule as a whole as it moves across the surface, defying the 'classical' laws that it's simply too big to feel quantum effects.

'Zero-point energy' moving within a pyrrole molecule is unexpectedly sensitive to the exact site occupied by the molecule on the surface. In moving from one site to another, the 'activation energy' must include a sizeable contribution due to the change in the quantum 'zero-point energy'.

Scientists believe the effect is particularly noticeable in the case of pyrrole because the 'activation energy' needed for diffusion is particularly small, but that many other similar molecules ought to show the same kind of behavior.

"Understanding the nature of molecular diffusion on metal surfaces is of great current interest, due to efforts to manufacture two-dimensional networks of ring-like molecules for use in optical, electronic or spintronic devices," said Dr Stephen Jenkins, who heads up the Surface Science Group in Cambridge's Department of Chemistry.

"The balance between the activation energy and the energy barrier that sticks the molecules to the surface is critical in determining which networks are able to form under different conditions."

###


ELSE PRESS RELEASES FROM THIS DATE:

Fish win fights on strength of personality

2013-04-26
When predicting the outcome of a fight, the big guy doesn't always win suggests new research on fish. Scientists at the University of Exeter and Texas A&M University found that when fish fight over food, it is personality, rather than size, that determines whether they will be victorious. The findings suggest that when resources are in short supply personality traits such as aggression could be more important than strength when it comes to survival. The study, published in the journal Behavioral Ecology and Sociobiology, found that small fish were able to do well in contests ...

Forthcoming study explores use of intermittent fasting in diabetes as cardiovascular disease

2013-04-26
Los Angeles, CA (April 26, 2013) – Intermittent fasting is all the rage, but scientific evidence showing how such regimes affect human health is not always clear cut. Now a scientific review in the British Journal of Diabetes and Vascular Disease published by SAGE, suggests that fasting diets may help those with diabetes and cardiovascular disease, alongside established weight loss claims. Intermittent fasting –fasting on a given number of consecutive or alternate days – has recently been hailed as a path to weight loss and improved cardiovascular risk. A team led by ...

Flu and bacteria: Better prognosis for this potentially fatal combination

2013-04-26
This press release is available in German. The flu is caused by an infection with the influenza virus, which mainly attacks the upper respiratory tract – the nose, throat and bronchi and rarely also the lungs. According to the World Health Organization (WHO), around five to 15 percent of the population are affected by upper respiratory tract infections during seasonal flu outbreaks, and between 250 000-500 000 people die of the illness every year. However, a main cause of death in people having the flu is actually a secondary infection with bacteria. Influenza increases ...

Developmental neurobiology: How the brain folds to fit

2013-04-26
During fetal development of the mammalian brain, the cerebral cortex undergoes a marked expansion in surface area in some species, which is accommodated by folding of the tissue in species with most expanded neuron numbers and surface area. Researchers have now identified a key regulator of this crucial process. Different regions of the mammalian brain are devoted to the performance of specific tasks. This in turn imposes particular demands on their development and structural organization. In the vertebrate forebrain, for instance, the cerebral cortex – which is responsible ...

Using mobile phone apps in weight-loss programs

2013-04-26
Mobile phones using text messaging and monitoring have been shown to be useful additions to health programs. The objective of this study was to develop and evaluate a weight-loss intervention delivered by a smartphone app that supported individuals embarking on a diet and that was evidenced-based. Researchers developed and tested a mobile phone application (app) to support individuals embarking on a partial meal replacement program (MRP). Overweight or obese women were randomly allocated to one of two study groups an intervention group and a control group. The intervention ...

Protein shaped like a spider

2013-04-26
This press release is available in German. The protein C4BP is similar to a spider in its spatial form with eight "arms". The structure of the "spider body" has recently been described in detail by researchers from the Helmholtz Centre for Infection Research (HZI) in Braunschweig and the Technische Universität Darmstadt. This leads the scientists to unconventional ideas – the protein is possibly suitable as a scaffold for the transport of active pharmaceutical substances, particularly biomolecules. The researchers are publishing their results in the current edition ...

New excavations indicate use of fertilizers 5,000 years ago

2013-04-26
Researchers from the University of Gothenburg, Sweden, have spent many years studying the remains of a Stone Age community in Karleby outside the town of Falköping, Sweden. The researchers have for example tried to identify parts of the inhabitants' diet. Right now they are looking for evidence that fertilisers were used already during the Scandinavian Stone Age, and the results of their first analyses may be exactly what they are looking for. Using remains of grains and other plants and some highly advanced analysis techniques, the two researchers and archaeologists ...

Computer scientists suggest new spin on origins of evolvability

2013-04-26
Scientists have long observed that species seem to have become increasingly capable of evolving in response to changes in the environment. But computer science researchers now say that the popular explanation of competition to survive in nature may not actually be necessary for evolvability to increase. In a paper published this week in PLOS ONE, the researchers report that evolvability can increase over generations regardless of whether species are competing for food, habitat or other factors. Using a simulated model they designed to mimic how organisms evolve, the ...

Sea surface temperatures reach highest level in 150 years

2013-04-26
Sea surface temperatures in the Northeast Shelf Large Marine Ecosystem during 2012 were the highest recorded in 150 years, according to the latest Ecosystem Advisory issued by NOAA's Northeast Fisheries Science Center (NEFSC). These high sea surface temperatures (SSTs) are the latest in a trend of above average temperature seen during the spring and summer seasons, and part of a pattern of elevated temperatures occurring in the Northwest Atlantic, but not seen elsewhere in the ocean basin over the past century. The advisory reports on conditions in the second half of ...

Federally funded research & development centers employed more than 3,000 postdoctoral researchers

2013-04-26
According to a recent report released by the National Science Foundation, 22 of the nation's 39 federally funded research and development centers (FFRDCs) employed 3,011 postdocs in 2010, the year the latest data are available. Three out of every four postdocs employed in the FFRDCs in 2010 were men. Foreign nationals on temporary visas made up 60 percent of all postdocs employed in FFRDCs. Men constituted a higher percentage of foreign nationals than of U.S. citizens and permanent residents--78 percent versus 72 percent. Among U.S. citizens and permanent residents, ...

LAST 30 PRESS RELEASES:

CMD-OPT model enables the discovery of a potent and selective RIPK2 inhibitor as preclinical candidate for the treatment of acute liver injury

Melatonin receptor 1a alleviates sleep fragmentation-aggravated testicular injury in T2DM by suppression of TAB1/TAK1 complex through FGFR1

Single-cell RNA sequencing reveals Shen-Bai-Jie-Du decoction retards colorectal tumorigenesis by regulating the TMEM131–TNF signaling pathway-mediated differentiation of immunosuppressive dendritic ce

Acta Pharmaceutica Sinica B Volume 15, Issue 7 Publishes

New research expands laser technology

Targeted radiation offers promise in patients with metastasized small cell lung cancer to the brain

A high clinically translatable strategy to anti-aging using hyaluronic acid and silk fibroin co-crosslinked hydrogels as dermal regenerative fillers

Mount Sinai researchers uncover differences in how males and females change their mind when reflecting on past mistakes

CTE and normal aging are difficult to distinguish, new study finds

Molecular arms race: How the genome defends itself against internal enemies

Tiny chip speeds up antibody mapping for faster vaccine design

KTU experts reveal why cultural heritage is important for community unity

More misfolded proteins than previously known may contribute to Alzheimer’s and dementia

“Too much going on”: Autistic adults overwhelmed by non-verbal social cues

What’s driving America’s deep freezes in a warming world?

A key role of brain protein in learning and memory is deciphered by scientists

Heart attacks don’t follow a Hollywood script

Erin M. Schuman wins 2026 Nakasone Award for discovery on neural synapse function and change during formation of memories

Global ocean analysis could replace costly in-situ sound speed profiles in seafloor positioning, study finds

Power in numbers: Small group professional coaching reduces rates of physician burnout by nearly 30%

Carbon capture, utilization, and storage: A comprehensive review of CCUS-EOR

New high-temperature stable dispersed particle gel for enhanced profile control in CCUS applications

State gun laws and firearm-related homicides and suicides

Use of tobacco and cannabis following state-level cannabis legalization

Long-term obesity and biological aging in young adults

Eindhoven University of Technology and JMIR Publications announce unlimited open access publishing agreement

Orphan nuclear receptors in metabolic dysfunction-associated steatotic liver disease development

A technological breakthrough for ultra-fast and greener AI

Pusan National University researchers identify key barriers hindering data-driven smart manufacturing adoption

Inking heterometallic nanosheets: A scalable breakthrough for coating, electronics, and electrocatalyst applications

[Press-News.org] Movement of pyrrole molecules defy 'classical' physics