Turbulent Flows in 2-D Can Be Calculated in New Model

Turbulent flows have challenged researchers for centuries. It is impossible to predict chaotic weather more than a week in advance. Wind resistance on a plane or a car cannot be calculated precisely, since it is determined by atmospheric turbulence. Now, however, researchers from the Niels Bohr Institute have succeeded in developing a statistical model that can replicate the chaotic flows and thereby provide a better understanding of the process.

The research results are published in the scientific journal Physics of Fluids.

"Without knowing the movements in detail, we know that they happen in such a way that the kinetic energy is conserved," explains Peter Ditlevsen, a research associate professor at the Niels Bohr Institute at the University of Copenhagen. He explains that when a liquid or air is set in motion, for example, if you create large eddies in a bathtub by stirring the water, it will transpire, that when you stop stirring, smaller and smaller eddies will continue to be created, while the large ones slowly die out. Finally, the movement in the smallest eddies are converted into heat. The entire process is called an energy cascade from large scales to small scales and is absolutely fundamental for understanding chaotic turbulent flow.

If the motion is limited to only being able to take place on a single plane, that is, two dimensions (2D), instead of in a volume, that is, three dimensions (3D), it will happen quite differently. The reason is that the flow cannot release its energy as small eddies cannot easily be formed in two dimensions. In two dimensions, both the energy and eddy density (which is called enstrophy) is retained in the flow, unlike in three dimensions, where only the energy is preserved.

Complicated calculations in 3D

A complex motion equation that has been known for almost 200 years, the so-called Navier-Stokes equation, is used to calculate the air's turbulent 3D movements. But even the world's most powerful computers, which have been dedicated to just this purpose, can only provide an approximate solution to the equation.

In order to describe the turbulent cascade processes, the researchers have therefore developed simplified mathematical models that are much easier to fully investigate in with computer calculations. The models have the same behaviour as the Navier-Stokes equation, but the models have not been able to reproduce the so-called inverse cascade in 2D.

Until now, the models have been too limited to show both the eddy density cascades down to small scales and the energy cascades up to large scales. They have been able to simulate the one cascade or the other, but not both simultaneously.

Simpler calculations in 2D

However, Peter Ditlevsen has now succeeded in developing such a cascade model that can reproduce the double cascade process in 2D turbulence.

"Turbulence can occur as a somewhat exotic phenomena. Though not in this case: Motion in the atmosphere, the wind and the weather is largely two-dimensional. The movements on the vertical axis are 100 to 1000 times less than those on the horizontal axis. The air has a much more difficult time moving vertically, so the movement of the weather systems movement is two-dimensional turbulence. This means that it is possible to predict the weather a ways ahead of time. If the movement had been three-dimensional, it would be dominated by small eddies, which are completely unpredictable, like when you see autumn leaves randomly floating around in a courtyard," explains Peter Ditlevsen.

The turbulent flows occur over a vast span of scales, so when researchers want to understand the processes, they have to study simplified models.

"With the new model of the two-dimensional turbulence we are one step closer to understanding which factors in the motion equations govern how energy is distributed in the flow," explains Peter Ditlevsen.

Journal Reference:

1.      Peter D. Ditlevsen. A stochastic model of cascades in two-dimensional turbulence. Physics of Fluids, 2012; 24 (10): 105109 DOI: 10.1063/1.4761834

Tweet

Planet Found in Nearest Star System to Earth: HARPS Instrument Finds Earth-Mass Exoplanet Orbiting Alpha Centauri B

European astronomers have discovered a planet with about the mass of Earth orbiting a star in the Alpha Centauri system -- the nearest to Earth. It is also the lightest exoplanet ever discovered around a star like the Sun. The planet was detected using the HARPS instrument on the 3.6-metre telescope at ESO's La Silla Observatory in Chile.

The results will appear online in the journal Nature on Oct. 17, 2012.

Alpha Centauri is one of the brightest stars in the southern skies and is the nearest stellar system to our Solar System -- only 4.3 light-years away. It is actually a triple star -- a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri [1]. Since the nineteenth century astronomers have speculated about planets orbiting these bodies, the closest possible abodes for life beyond the Solar System, but searches of increasing precision had revealed nothing. Until now.

"Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days," says Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal), lead author of the paper. "It's an extraordinary discovery and it has pushed our technique to the limit!"

The European team detected the planet by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet [2]. The effect is minute -- it causes the star to move back and forth by no more than 51 centimetres per second (1.8 km/hour), about the speed of a baby crawling. This is the highest precision ever achieved using this method.

Alpha Centauri B is very similar to the Sun but slightly smaller and less bright. The newly discovered planet, with a mass of a little more than that of Earth [3], is orbiting about six million kilometres away from the star, much closer than Mercury is to the Sun in the Solar System. The orbit of the other bright component of the double star, Alpha Centauri A, keeps it hundreds of times further away, but it would still be a very brilliant object in the planet's skies.

The first exoplanet around a Sun-like star was found by the same team back in 1995 and since then there have been more than 800 confirmed discoveries, but most are much bigger than Earth, and many are as big as Jupiter [4]. The challenge astronomers now face is to detect and characterise a planet of mass comparable to Earth that is orbiting in the habitable zone [5] around another star. The first step has now been taken [6].

"This is the first planet with a mass similar to Earth ever found around a star like the Sun. Its orbit is very close to its star and it must be much too hot for life as we know it," adds Stéphane Udry (Geneva Observatory), a co-author of the paper and member of the team, "but it may well be just one planet in a system of several. Our other HARPS results, and new findings from Kepler, both show clearly that the majority of low-mass planets are found in such systems."

"This result represents a major step towards the detection of a twin Earth in the immediate vicinity of the Sun. We live in exciting times!" concludes Xavier Dumusque.

Notes

[1] The components of a multiple star are named by adding uppercase letters to the name of the star. Alpha Centauri A is the brightest component, Alpha Centauri B is the slightly fainter second star and Alpha Centauri C is the much fainter Proxima Centauri. Proxima Centauri is slightly closer to Earth than A or B and hence is formally the closest star.

[2] HARPS measures the radial velocity of a star -- its speed towards or away from Earth -- with extraordinary precision. A planet in orbit around a star causes the star to regularly move towards and away from a distant observer on Earth. Due to the Doppler effect, this radial velocity change induces a shift of the star's spectrum towards longer wavelengths as it moves away (called a redshift) and a blueshift (towards shorter wavelengths) as it approaches. This tiny shift of the star's spectrum can be measured with a high-precision spectrograph such as HARPS and used to infer the presence of a planet.

[3] Using the radial velocity method, astronomers can only estimate a minimum mass for a planet as the mass estimate also depends on the tilt of the orbital plane relative to the line of sight, which is unknown. But, from a statistical point of view, this minimum mass is often close to the real mass of the planet.

[4] NASA's Kepler mission has found 2300 candidate planets using an alternative method -- searching for the slight drop in the brightness of a star as a planet passes in front of it (transits) and blocks some of the light. The majority of planet candidates detected by this transit method are very distant from us. But, in contrast, the planets found by HARPS are around stars close to the Sun -- with the new discovery being the closest yet. This makes them better targets for many kinds of additional follow-up observations such as characterising the planet's atmosphere.

[5] The habitable zone is a narrow annular region around a star in which water may be present in liquid form if conditions are right.

[6] ESPRESSO, the Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations, is to be installed on the ESO Very Large Telescope. Currently undergoing final design, it is scheduled to start operating in late-2016 or early-2017. ESPRESSO will feature radial velocity precision of 0.35 km/hour or less. For comparison, Earth induces a 0.32 km/hour radial velocity on the Sun. This resolution should thus enable ESPRESSO to discover Earth-mass planets in the habitable zone. The ESPRESSO consortium is led by team members responsible for the current discovery.

More information

This research was presented in a paper "An Earth mass planet orbiting Alpha Centauri B," to appear online in the journalNature on Oct. 17, 2012.

The team is composed of Xavier Dumusque (Observatoire de Genève, Switzerland; Centro de Astrofisica da Universidade do Porto, Portugal), Francesco Pepe (Observatoire de Genève), Christophe Lovis (Observatoire de Genève), Damien Ségransan (Observatoire de Genève), Johannes Sahlmann (Observatoire de Genève), Willy Benz (Universität Bern, Switzerland), François Bouchy (Observatoire de Genève; Institut d'Astrophysique de Paris, France), Michel Mayor (Observatoire de Genève), Didier Queloz (Observatoire de Genève), Nuno Santos (Centro de Astrofisica da Universidade do Porto) and Stéphane Udry (Observatoire de Genève).

Journal Reference:

1.      Xavier Dumusque, Francesco Pepe, Christophe Lovis, Damien Ségransan, Johannes Sahlmann, Willy Benz, François Bouchy, Michel Mayor, Didier Queloz, Nuno Santos, Stéphane Udry. An Earth-mass planet orbiting α Centauri B. Nature, 2012; DOI: 10.1038/nature11572

Tweet

Carbon Dioxide: Our Salvation from a Future Ice Age?

Humankind's emissions of fossil carbon and the resulting increase in temperature could prove to be our salvation from the next ice age. According to new research from the University of Gothenburg, Sweden, the current increase in the extent of peatland is having the opposite effect.

"We are probably entering a new ice age right now. However, we're not noticing it due to the effects of carbon dioxide," says researcher Professor Lars Franzén.

Looking back over the past three million years, Earth has experienced at least 30 periods of ice age, known as ice age pulses. The periods in between are called interglacials. The researchers believe that the Little Ice Age of the 16^th to 18^th centuries may have been halted as a result of human activity. Increased felling of woodlands and growing areas of agricultural land, combined with the early stages of industrialisation, resulted in increased emissions of carbon dioxide which probably slowed down, or even reversed, the cooling trend.

"It is certainly possible that mankind's various activities contributed towards extending our ice age interval by keeping carbon dioxide levels high enough," explains Lars Franzén, Professor of Physical Geography at the University of Gothenburg.

"Without the human impact, the inevitable progression towards an ice age would have continued. The spread of peatlands is an important factor."

Peatlands act as carbon sinks, meaning that they absorb carbon dioxide from the atmosphere. They are a dynamic landscape element and currently cover around four percent of Earth's land area. Most peatlands are found in temperate areas north and south of the 45th parallel.

Around 16 percent of Sweden is covered by peatland. Peatlands grow in height and spread across their surroundings by waterlogging woodlands. They are also one of the biggest terrestrial sinks of atmospheric carbon dioxide. Each year, around 20 grams of carbon are absorbed by every square metre of peatland.

"By using the National Land Survey of Sweden's altitude database, we have calculated how much of Sweden could be covered by peatlands during an interglacial. We have taken a maximum terrain incline of three degrees as our upper limit, and have also excluded all lakes and areas with substrata that are unsuitable for peatland formation."

The researchers found that around half of Sweden's surface could be covered by peat. In such a case, the carbon dioxide sink would increase by a factor of between six and ten compared with the current situation.

"If we accept that rising levels of carbon dioxide in the atmosphere lead to an increase in global temperature, the logical conclusion must be that reduced levels lead to a drop in temperature."

The relationship between carbon dioxide and temperature is not linear. Instead, lower levels result in a greater degree of cooling than the degree of warming achieved by a corresponding increase.

"There have been no emissions of fossil carbon during earlier interglacials. Carbon sequestration in peatland may therefore be one of the main reasons why ice age conditions have occurred time after time."

Using calculations for Swedish conditions, the researchers are also producing a rough estimate of the global carbon sink effect if all temperate peatlands were to grow in the same way.

"Our calculations show that the peatlands could contribute towards global cooling equivalent to five watts per square metre. There is a great deal of evidence to suggest that we are near the end of the current interglacial."

Professor Franzén and three other researchers have published their findings in the journal Mires and Peat.

Journal Reference:

1.      Franzén, L.G., F. Lindberg, V. Viklander & A. Walther. The potential peatland extent and carbon sink in Sweden, as related to the Peatland/Ice Age Hypothesis. Mires and Peat, 2012

Tweet

New Approach to Combat Viral Infections Identified

When a virus such as influenza invades our bodies, interferon proteins are among the first immune molecules produced to fight off the attack. Interferon can also play a role in suppressing tumor growth and the effects of autoimmune diseases, and doctors may use an artificial form of interferon to treat patients with certain cancers or multiple sclerosis. But even this approach sometimes fails when patients' bodies reject the foreign interferon or growing resistant to its effects.

A study by scientists from the University of Pennsylvania School of Veterinary Medicine offers a new strategy for enhancing the effects of interferon in fighting off infection. The research suggests that, by targeting a particular molecule in the interferon signaling pathway, specially designed drugs may be able to boost the activity of a person's own interferon, augmenting the immune system's fight against viruses. It's possible that the same drugs might also be effective against some types of cancer and certain autoimmune conditions.

Serge Fuchs, a professor of cell biology in Penn Vet's Department of Animal Biology and director of the School's Mari Lowe Comparative Oncology Center, was the senior author on the paper published in theProceedings of the National Academy of Sciences.

"The practical significance of our study is a demonstration of the ability to use emerging pharmaceuticals to reactivate an individual's own interferon or to use a reduced dose to get the same effect," Fuchs said.

Christopher Carbone and Hui Zheng of the Department of Animal Biology and John Lewis and Alexander Reiter of the Department of Clinical Studies played leading roles in the study. Additional Penn Vet collaborators were Sabyasachi Bhattacharya, Paula Henthorn and Kendra Bence. Zhong-Yin Zhang of Indiana University School of Medicine and Darren Baker of Biogen Idec also contributed.

The research would have been impossible without the team's comparative-medicine approach, in which they examined the effects of activating the interferon pathway in both human cells and in cats affected by a naturally occurring disease. Mice would normally be the model organism of choice for such a study, but they lack a molecular element of the interferon pathway that humans and cats share.

"Mice are very convenient, but they may not always recapitulate human diseases that well," Fuchs said. "Veterinary diseases happen naturally, and they provide a less convenient but a more truthful recapitulation of the human situation."

Interferon fights viruses by binding to an interferon receptor on cells, triggering a cascade of other molecular events and leading to the production of proteins that prevent viruses from reproducing or that stimulate other immune responses. But because too much interferon can harm the host's body, this signaling cascade has a built-in brake: Using a separate molecular pathway, interferon triggers the body's cells to remove its own receptor, so the immune system attack doesn't go on indefinitely.

"It's very important to understand what regulates the responsiveness of cells to interferon, and a major factor is the levels of cell-surface receptors," Fuchs said.

Although the researchers' investigations of these pathways led them to identify a target for improving the body's virus-fighting ability, they didn't set out to discover a drug. Rather, they were attempting to solve a paradox of cell biology.

The paradox rests on the fact that many steps in the interferon-signaling pathway involve adding a molecule of phosphate to proteins in the cascade. Interferon itself promotes the addition of phosphate onto the interferon receptor, yet previous evidence suggested that the receptor resisted being removed by the cell if it had phosphate added. Given that interferon does in fact trigger the removal of its own receptor, the research team hypothesized that another enzyme must be at work in the pathway to remove the phosphate molecule from the receptor so it could be consumed by the body's cells to ramp down the immune-system response to viruses.

Performing a screening for this putative enzyme, they identified protein tyrosine phosphatase 1 B (PTP1B) as a likely candidate. In a series of experiments, the researchers confirmed that blocking PTP1B decreased the removal of the interferon receptor. As a result, interferon signaling became enhanced. Using human cells infected with hepatitis C, the researchers found that adding a PTP1B inhibitor allowed smaller doses of interferon to be effective in keeping the virus from reproducing. They demonstrated a similar effect in human cells infected with vesicular stomatitis virus.

Aiding in their work was the fact that pharmaceutical companies have already designed multiple drugs that inhibit the activity of PTP1B but for a completely separate reason than the enzyme's involvement in interferon signaling.

"PTP1B also works on the leptin receptor," Fuchs said. "This is the pathway that regulates satiety, appetite and weight gain. So in the past 10 years there have been massive industrial and academic undertaking to develop PTP1B inhibitors to treat obesity and diabetes."

To see how these PTP1B inhibitors would impact viral infections in a living organism, the researchers could not use mice because mice lack a portion of the receptor that PTP1B acts upon, and so blocking PTP1B does not impact interferon signaling in the same way as it does in humans and other mammals. Instead, they examined five cats that had been enrolled by their owners in the study. Each was suffering from chronic stomatitis, a condition that involves substantial inflammation in the mouth and makes it painful for the cats to eat and groom. The cats received a single injection of a PTP1B inhibitor. Two weeks later, all five showed noticeable reductions in redness and inflammation, providing clinical evidence that these drugs could be used to treat infection.

Fuchs said that what seemed like a drawback in the study -- that it couldn't be effectively modeled in mice -- ended up being a benefit, as naturally occurring diseases in animals such as cat and dogs more closely mimic many human diseases.

Because interferon is known to suppress tumors and help multiple sclerosis patients, the results of this study give the researchers optimism that PTP1B could be a target for anti-cancer and anti-autoimmune disease therapies.

As a next step, they plan to test the PTP1B inhibitors in a model of feline immunodeficiency virus, or the cat version of AIDS, to see if its virus-fighting capabilities can have an effect against that infection.

The study was supported by the National Institutes of Health and the Mari Lowe Center for Comparative Oncology Research at the University of Pennsylvania.

Journal Reference:

1.      C. J. Carbone, H. Zheng, S. Bhattacharya, J. R. Lewis, A. M. Reiter, P. Henthorn, Z.-Y. Zhang, D. P. Baker, R. Ukkiramapandian, K. K. Bence, S. Y. Fuchs. Protein tyrosine phosphatase 1B is a key regulator of IFNAR1 endocytosis and a target for antiviral therapies.Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1211491109

Tweet

Scientific Explanation to Why People Perform Better After Receiving a Compliment

Japanese scientists have found scientific proof that people doing exercises appear to perform better when another person compliments them. The research was carried out by a group lead by National Institute for Physiological Sciences Professor Norihiro Sadato, Graduate University for Advanced Studies graduate student Sho Sugawara, Nagoya Institute of Technology Tenure-Track Associate Professor Satoshi Tanaka, and in collaboration with Research Center for Advanced Science and Technology Associate Professor Katsumi Watanabe.

The team had previously discovered that the same area of the brain, the striatum, is activated when a person is rewarded a compliment or cash. Their latest research could suggest that when the striatum is activated, it seems to encourage the person to perform better during exercises.

Forty-eight adults recruited for the study were asked to learn and perform a specific finger pattern (pushing keys on a keyboard in a particular sequence as fast as possible in 30 seconds). Once participants had learned the finger exercise, they were separated into three groups. One group included an evaluator who would compliment participants individually, another group involved individuals who would watch another participant receive a compliment, and the third group involved individuals who evaluated their own performance on a graph. When the participants were asked to repeat the finger exercise the next day, the group of participants who received direct compliments from an evaluator performed better than participants from the other groups. It indicates that receiving a compliment after exercising stimulates the individual to perform better afterwards.

According to Professor Sadato, "To the brain, receiving a compliment is as much a social reward as being rewarded money. We've been able to find scientific proof that a person performs better when they receive a social reward after completing an exercise.There seems to be scientific validity behind the message 'praise to encourage improvement'. Complimenting someone could become an easy and effective strategy to use in the classroom and during rehabilitation."

This research was funded by the Japanese Ministry of Education, Culture, Sports, Science and Technology's Sciences Research Grant (KAKENHI).

Journal Reference:

1.      Sho K. Sugawara, Satoshi Tanaka, Shuntaro Okazaki, Katsumi Watanabe, Norihiro Sadato. Social Rewards Enhance Offline Improvements in Motor Skill. PLoS ONE, 2012; 7 (11): e48174 DOI:10.1371/journal.pone.0048174

Tweet

Compound in Grapes, Red Wine Could Be Key to Fighting Prostate Cancer

Resveratrol, a compound found commonly in grape skins and red wine, has been shown to have several beneficial effects on human health, including cardiovascular health and stroke prevention. Now, a University of Missouri researcher has discovered that the compound can make prostate tumor cells more susceptible to radiation treatment, increasing the chances of a full recovery from all types of prostate cancer, including aggressive tumors.

  

"Other studies have noted that resveratrol made tumor cells more susceptible to chemotherapy, and we wanted to see if it had the same effect for radiation therapy," said Michael Nicholl, an assistant professor of surgical oncology in the MU School of Medicine. "We found that when exposed to the compound, the tumor cells were more susceptible to radiation treatment, but that the effect was greater than just treating with both compounds separately."

Prostate tumor cells contain very low levels of two proteins, perforin and granzyme B, which can function together to kill cells. However, both proteins need to be highly "expressed" to kill tumor cells. In his study, when Nicholl introduced resveratrol into the prostate tumor cells, the activity of the two proteins increased greatly. Following radiation treatment, Nicholl found that up to 97 percent of the tumor cells died, which is a much higher percentage than treatment with radiation alone.

"It is critical that both proteins, perforin and granzyme B, are present in order to kill the tumor cells, and we found that the resveratrol helped to increase their activity in prostate tumor cells," Nicholl said. "Following the resveratrol-radiation treatment, we realized that we were able to kill many more tumor cells when compared with treating the tumor with radiation alone. It's important to note that this killed all types of prostate tumor cells, including aggressive tumor cells."

Resveratrol is present in grape skins and red wine and available over-the-counter in many health food sections at grocery stores. However, the dosage needed to have an effect on tumor cells is so great that many people would experience uncomfortable side effects.

"We don't need a large dose at the site of the tumor, but the body processes this compound so efficiently that a person needs to ingest a lot of resveratrol to make sure enough of it ends up at the tumor site. Because of that challenge, we have to look at different delivery methods for this compound to be effective," Nicholl said. "It's very attractive as a therapeutic agent since it is a natural compound and something that most of us have consumed in our lifetimes."

Nicholl said that the next step would be to test the procedure in an animal model before any clinical trials can be initiated. Nicholl's studies were published in the Journal of Andrologyand Cancer Science. The early-stage results of this research are promising. If additional studies, including animal studies, are successful within the next few years, MU officials will request authority from the federal government to begin human drug development (this is commonly referred to as the "investigative new drug" status). After this status has been granted, researchers may conduct human clinical trials with the hope of developing new treatments for cancer.

Journal References:

1.      Y. Fang, E. J. Herrick, M. B. Nicholl. A Possible Role for Perforin and Granzyme B in Resveratrol-Enhanced Radiosensitivity of Prostate Cancer. Journal of Andrology, 2011; 33 (4): 752 DOI:10.2164/jandrol.111.015164

2.      Yujiang Fang, Vincent G. DeMarco, Michael B. Nicholl.Resveratrol enhances radiation sensitivity in prostate cancer by inhibiting cell proliferation and promoting cell senescence and apoptosis. Cancer Science, 2012; 103 (6): 1090 DOI: 10.1111/j.1349-7006.2012.02272.x

Tweet

Screening for Lung Cancer Saves Lives

Lung cancer is the No. 1 cause of cancer deaths in the United States, despite the fact it is largely preventable. For people at high risk of developing lung cancer, such as current or former longtime smokers, screening for the disease with low-dose CT scans is now a viable option that has been shown to significantly reduce mortality rates. In conjunction with National Lung Cancer Awareness Month, Seattle Cancer Care Alliance (SCCA) wants to raise awareness about the importance of prevention and early detection for at-risk populations.

A majority of patients diagnosed with lung cancer already have incurable disease at the time of diagnosis. The large number of patients with advanced lung cancer is the reason it is the leading cause of cancer-related death in the United States -- more than breast, colon and prostate cancer combined. However, by participating in screening that can detect cancer in its earliest stages, lung cancer mortality can be lowered by as much as 20 percent, according to results from the National Lung Screening Trial (NLST) that were published in June 2011.

"Low-dose computed tomography screening for patients at high risk of lung cancer saves lives," said David Madtes, M.D., director of SCCA's Lung Cancer Early Detection and Prevention Clinic and director of the low-dose CT screening program. "It is recommended by more than a dozen medical societies and patient advocacy groups including the American Cancer Society and the American Lung Association."

While lung cancer screening is not currently a routine part of preventive medical care like mammography for breast cancer screening or the PSA blood test to screen for prostate cancer, the results of the NLST trial are changing clinical practice. Lung cancer experts now support lung cancer screening to provide the opportunity to detect cancers at an earlier, treatable and curable stage.

Douglas Wood, M.D., professor and chief of Cardiothoracic Surgery at the University of Washington and a member of the multidisciplinary team that treats lung cancer patients at SCCA, chairs the National Comprehensive Cancer Network (NCCN) Lung Cancer Screening Panel which supports creating policies that allow more patients access to screenings. Wood led the NCCN group that published the initial set of guidelines in November 2011 and the guidelines revision process this summer, which aims to make screening available with the support of insurance and Medicare.

"Lung cancer screening for those at high risk is the biggest game changer in lung cancer treatment in a generation," Wood said. "The NLST study found that such screening could reduce mortality by 20 percent. We are on the cusp of changing guidelines and policies to help offer screening that could impact millions of people."

Patients at high risk for lung cancer who benefited from CT screening in the NLST met the following characteristics:

·         Ages 55-74

·         Current smokers or those who quit within the last 15 years

·         Previous smokers with a 30 or more pack-year smoking history ("pack years" equals the average number of packs of cigarettes smoked per day multiplied by the number of years a person has smoked)

In addition to the above characteristics, the NCCN considers individuals to be at high risk for lung cancer if they have the characteristics listed below.

·         Age 50 or older

·         Smoked for 20 or more pack years

·         Documented high radon exposure

·         Occupational exposure to silica, cadmium, asbestos, arsenic, beryllium, chromium, nickel or diesel fumes

·         A survivor of lung cancer, lymphoma or head and neck cancer

·         A history of chronic obstructive pulmonary disease or pulmonary fibrosis

·         A family history of lung cancer

Currently, low-dose CT screening is not covered by most insurance carriers, yet the out-of-pocket cost is relatively low at $300. Most follow-up care required after the exam will be covered by insurance or Medicare/Medicaid.

Tweet