Water window imaging opportunity

A new theoretical study elucidates mechanisms that could help in producing coherent radiations, ultimately promoting high-contrast imaging of biological samples

2014-08-21

(Press-News.org) Ever heard of the water window? It consists of radiations in the 3.3 to 4.4 nanometre range, which are not absorbed by the water in biological tissues. New theoretical findings show that it is possible to develop coherent radiations within the water window. These could be the basis of an optimal technique to obtain a high-contrast image of the biological samples or to be used in high-precision spectroscopy. Now, a new theoretical study identifies the physical mechanism needed to efficiently generate the harmonic radiations—which are multiples of an incoming laser’s frequency—at high laser intensities that occur beyond the saturation threshold of atoms and molecules. These findings, aimed at improving conventional methods of coherent radiation production to reach the water window, were recently published in the EPJ D by José Pérez-Hernández from the Centre for Pulsated Laser, CLPU, in Salamanca, Spain, and colleagues. When an intense and short laser pulse interacts with an atom or molecule, one of the resultant physical processes is the High-order Harmonic Generation (HHG) process, which is capable of changing the driving laser pulse into new harmonic frequencies. HHG also provides a direct way to synthesise atto-second pulses (10-18s range) and produce coherent radiation in the extreme UV range, dubbed XUV and EUV. In previous similar work, studies focused on hydrogen as the atomic target. In the present work, the authors extend the study to argon atoms—a gas typically providing a high enough frequency conversion efficiency to detect the HHG. The authors use the same formalism as in hydrogen studies, consisting in mathematical equations combined with a quantum mechanical approach using numerical computation and providing a quantitative description of the HHG spectrum. The experimental confirmation of the reported prediction, however, still remains a challenge. INFORMATION: Reference: Pérez-Hernández, J. A. et al. (2014). High order harmonic generation at high laser intensities beyond the tunnel regime. European Physical Journal D. DOI: 10.1140/epjd/e2014-50086-6 END

ELSE PRESS RELEASES FROM THIS DATE:

Study shows steep decline in tooth loss, increase in socioeconomic disparities

2014-08-21

Alexandria, Va., USA – The International and American Associations for Dental Research (IADR/AADR) have published a paper titled "Projections of U.S. Edentulism Prevalence Following Five Decades of Decline." This study, by lead researcher Gary Slade, University of North Carolina at Chapel Hill, USA, follows edentulism (tooth loss) over the last hundred years and highlights the numbers of people losing teeth and requiring dentures. It is published in the OnlineFirst portion of the IADR/AADR Journal of Dental Research (JDR). The researchers of this study investigated population ...

Tropical Storm Karina looks like a giant 'number 9' from space

2014-08-21

Despite being the eleventh tropical cyclone of the Eastern Pacific Ocean Hurricane Season, Karina looked like a giant number nine from NASA's Aqua satellite. Tropical Storm Karina was weakening on August 20 when NASA's Terra satellite passed overhead. The Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard Terra snapped a visible image of Tropical Storm Karina on August 20 at 19:40 UTC (3:40 p.m. EDT). The MODIS image showed that a thick band of strong thunderstorms spiraled into Karina's center from the southeast. The band of thunderstorms wrapped ...

Insulin offers new hope for the treatment of acute pancreatitis

2014-08-21

Acute pancreatitis involves the pancreas digesting itself resulting in severe abdominal pain, vomiting and systemic inflammation. Every year in the UK around 20,000 patients are diagnosed with the disease resulting in 1000 deaths. There is no immediate cure and treatment is restricted to intravenous fluid and nutritional support. Dr Jason Bruce, from the Faculty of Life Sciences, who led the research, said "The major causes of pancreatitis include bile acid reflux from gall stones and excessive alcohol intake combined with a high fat diet. In fact, the incidence of acute ...

Toothpaste fluorine formed in stars

2014-08-21

The fluorine that is found in products such as toothpaste was likely formed billions of years ago in now dead stars of the same type as our sun. This has been shown by astronomers at Lund University in Sweden, together with colleagues from Ireland and the USA. Fluorine can be found in everyday products such as toothpaste and fluorine chewing gum. However, the origins of the chemical element have been somewhat of a mystery. There have been three main theories about where it was created. The findings now presented support the theory that fluorine is formed in stars similar ...

Researchers found an important clue to potential treatments for absence seizures

2014-08-21

Absence seizures are believed to be elicited by T-type calcium channels in the thalamic reticular nucleus of the brain that regulate influxes of calcium. These channels enable thalamic reticular nucleus neurons to generate burst firing, leading the neurons to enter a hyper-excited state. In order to identify the relationship between burst firing and absence seizures, the researchers conducted an experiment to induce absence seizures in mice using gene targeting techniques to delete the T-type calcium channel CaV3.3. The results showed that mice that received a complete ...

Amplitude of sensory nerve action potential in early stage diabetic peripheral neuropathy

2014-08-21

Early diagnosis of diabetic peripheral neuropathy is important for the successful treatment of diabetes mellitus. Research group at the Fourth Affiliated Hospital of Kunming Medical University, China, led by Dr. Jianlin Wang sought to establish a sensitive index for nerve conduction studies in the early diagnosis of peripheral neuropathy in 500 patients with diabetes mellitus. Nerve conduction studies revealed that distal motor latency was longer, sensory nerve conduction velocity was slower, and sensory nerve action potential and amplitude of compound muscle action potential ...

Smartphone-loss anxiety disorder

2014-08-21

The smart phone has changed our behavior, sometimes for the better as we are now able to connect and engage with many more people than ever before, sometimes for the worse in that we may have become over-reliant on the connectivity with the outside world that these devices afford us. Either way, there is no going back for the majority of users who can almost instantaneously connect with hundreds if not thousands of people through the various social media and other applications available on such devices and not least through the humble phone call. However, our dependence ...

ADHD children make poor decisions due to less differentiated learning processes

2014-08-21

Which shirt do we put on in the morning? Do we drive to work or take the train? From which takeaway joint do we want to buy lunch? We make hundreds of different decisions every day. Even if these often only have a minimal impact, it is extremely important for our long-term personal development to make decisions that are as optimal as possible. People with ADHD often find this difficult, however. They are known to make impulsive decisions, often choosing options which bring a prompt but smaller reward instead of making a choice that yields a greater reward later on down ...

Learning to play the piano? Sleep on it!

2014-08-21

According to researchers at the University of Montreal, the regions of the brain below the cortex play an important role as we train our bodies' movements and, critically, they interact more effectively after a night of sleep. While researchers knew that sleep helped us the learn sequences of movements (motor learning), it was not known why. "The subcortical regions are important in information consolidation, especially information linked to a motor memory trace. When consolidation level is measured after a period of sleep, the brain network of these areas functions with ...

Electric sparks may alter evolution of lunar soil

2014-08-21

DURHAM, N.H. –- The moon appears to be a tranquil place, but modeling done by University of New Hampshire and NASA scientists suggests that, over the eons, periodic storms of solar energetic particles may have significantly altered the properties of the soil in the moon's coldest craters through the process of sparking—a finding that could change our understanding of the evolution of planetary surfaces in the solar system. The study, published recently in the Journal of Geophysical Research-Planets, proposes that high-energy particles from uncommon, large solar storms ...

Water window imaging opportunity

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: