(Press-News.org) "Many people are now saying: 'Is it really that easy? Then why didn't anyone think of it a long time ago?' But you have to have the right idea at the right time," says Annette Röttger, physicist at the Physikalisch-Technische Bundesanstalt (PTB), in a pleased way. Annette Röttger and her scientific team managed to do something that was previously thought to be impossible: they developed a primary standard for the measurement of short-lived radioactive thoron. Thoron measuring instruments from all over the world will now be calibrated at this unique device which is currently the only one of its kind in the world. This is the basis for accurate measurements of radioactive gas, which occurs naturally in the ground, can collect in living areas and whose progenies are considered carcinogenic.
The same as its sister isotope radon (Rn-222), the radioactive gas thoron (Rn-220) can also cause lung cancer through its progenies if these are breathed in over long periods of time and in high concentrations. The degree of the radiation exposure of living areas varies greatly and is dependent on the construction of the house and the way it is ventilated. The measurement of Rn-222 has worked very accurately for a long time, whereas measuring instruments for thoron have delivered results with considerable uncertainties up till now. And what was worse: sometimes the results were simply wrong! The exact measurement of thoron is, however, important for the estimation of risks, as at the same activity concentration, a 14-fold higher radiation level results from the thoron progenies than from the progenies of the Rn-222, which is already measured well.
"It was clear that all thoron measuring instruments need a uniform standard with which they can be calibrated so that all the measurements are comparable, and so that you know the uncertainty of each individual measuring instrument," explains Annette Röttger. But the development of a standard that is valid everywhere – metrologists speak of a primary standard – like the one that already exists for Rn-222, was considered impossible for a long time, because thoron has a relatively short half-life of only 55 seconds. The PTB team finally had a brilliant idea:
The core of the primary standard is a test container which is filled with a defined amount of thoron. In view of the short half-life, a closed container, such as for radon, did not come into question, as the activity would quickly decay in that, in a short time. For this reason the scientists developed a circuit system that constantly introduces newly produced thoron with a high flow air stream and keeps the activity in the container constant.
The production and the accurate measurement of the activity which was fed in, was a metrological challenge. It was possible through a novel measuring arrangement called the thoron emanation measuring facility (TEM). The activity thereby comes from a thorium (Th-228) preparation which continually produces thoron. A constant, strong air stream transports the thoron into the test container. The tough nut that had to be cracked was: how much thoron is transported away and how much stays in the source? The PTB team finally succeeded in determining this ratio to one tenth of a per cent exactly.
Parallel to operating the TEM, the measuring instrument to be calibrated can be connected to the test container. As a rule, all the connected devices show more or less different results. You might even have a factor of 4! The manufacturers then receive a correction factor from PTB with which they have to multiply the measurement result to get to the correct result.
As more and more geological and epidemiological studies in Asia, Europe and Latin America are focussed on thoron (to which little attention had been paid to date), the newly set up measuring arrangement at PTB is constantly fully booked by international customers.
###
Accurate measurement of radioactive thoron possible at last
PTB develops first primary standard worldwide for calibration of thoron measuring instruments
2011-03-08
ELSE PRESS RELEASES FROM THIS DATE:
You are what your mother ate
2011-03-08
Poor diet during pregnancy increases offspring's vulnerability to the effects of aging, new research has shown for the first time.
The research, by scientists from the University of Cambridge, provides important insight into why children born to mothers who consumed an unhealthy diet during pregnancy have an increased risk of type 2 diabetes (a significant contributing factor to heart disease and cancer) later in life.
"What is most exciting about these findings is that we are now starting to really understand how nutrition during the first nine months of life ...
1 in 3 doctors afraid to report underperforming colleagues
2011-03-08
Almost one in five UK doctors has had direct experience of an incompetent or poorly performing colleague in the past three years, finds a survey of professional values, published online in BMJ Quality & Safety.
Nearly three out of four of these doctors said they had sounded the alarm, but one in three of those who had not done so gave fear of retribution as the reason.
The study authors canvassed the views of almost 2,000 US doctors working in primary care and hospital medicine and over 1,000 of their UK peers in 2009 about various aspects of professional behaviour.
Topics ...
High levels of 'good' cholesterol may cut bowel cancer risk
2011-03-08
High levels of "good" (high density lipoprotein) HDL cholesterol seem to cut the risk of bowel cancer, suggests research published online in Gut.
The association is independent of other potentially cancer-inducing markers of inflammation in the blood.
The researchers base their findings on participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. This is tracking the long term impact of diet on the development of cancer in more than half a million people in 10 European countries, including the UK.
Some 1,200 people who developed ...
Acupuncture curbs severity of menopausal hot flushes
2011-03-08
Traditional Chinese acupuncture curbs the severity of hot flushes and other menopausal symptoms, suggests a small study published today in Acupuncture in Medicine.
The effects did not seem to be related to changes in levels of the hormones responsible for sparking the menopause and its associated symptoms, the study shows.
The authors base their findings on 53 middle aged women, all of whom were classified as being postmenopausal - they had spontaneously stopped having periods for a year. Their somatic (hot flushes) urogenital (vaginal dryness and urinary tract infection) ...
Suggesting genes' friends, Facebook-style
2011-03-08
Scientists at the European Molecular Biology Laboratory (EMBL) and the German Cancer Research Centre (DKFZ), both in Heidelberg, Germany, have developed a new method that uncovers the combined effects of genes. Published online today in Nature Methods, it helps understand how different genes can amplify, cancel out or mask each others' effects, and enables scientists to suggest genes that interfere with each other in much the same manner that facebook suggests friends.
To understand the connections between genetic make-up and traits like disease susceptibility, scientists ...
Older parents are happier with more children
2011-03-08
This release is available in German.
"Children may be a long-term investment in happiness," says MPIDR demographer Mikko Myrskylä. Together with Rachel Margolis from the University of Pennsylvania in Philadelphia, USA, he published the new study in the latest issue of the journal "Population and Development Review". It shows a global trend: while for parents under 30 the level of happiness decreases with the first and each additional child, mothers and fathers aged 30 to 39 feel as happy as childless peers until they have four children or more. From age 40 onwards parents ...
Unique frog helps amphibian conservation efforts
2011-03-08
A tropical frog – the only one of its kind in the world – is providing conservationists with exclusive insights into the genetic make-up of its closest endangered relatives.
University of Manchester scientists have allowed two critically endangered species of Central American Leaf frogs to interbreed, producing the unique frog – a hybrid of the two species. DNA tests using a harmless mouth swab showed that the two parent frogs were actually very closely related despite being different species.
The findings are important because DNA tests on frogs of the same species ...
Genome sequencing used to assess a novel form of Clostridium botulinum
2011-03-08
Scientists on the Norwich Research Park have sequenced the genome of a novel strain of Clostridium botulinum, one of the most dangerous pathogens known to man. The strain produces an unusual botulinum neurotoxin, known as type A5 neurotoxin, which was isolated by the Health Protection Agency (HPA), following a case of wound botulism.
Professor Mike Peck and his research group at the Institute of Food Research (IFR) study Clostridium botulinum. Their expertise is crucial for preventing food poisoning outbreaks in the UK and internationally and to understanding the threat ...
Otters on road to recovery in Andalusia
2011-03-08
Improved environmental conditions have enabled the otter (Lutra lutra) to spread in Andalusia over the past 20 years. However, the recovery of populations of this mammal has been "relatively" slow, and in some areas the impact of human activities still prevents the species from gaining a foothold.
"The high level of 'humanisation' of the landscape still acts as a strong impediment to the expansion of the otter, to such an extent that it is preventing the species from fully recovering its original distribution area", Miguel Clavero, lead author of the study and a researcher ...
Universal screening programs can uncover abuse, study finds
2011-03-08
TORONTO, ON., March 7, 2011—Screening every woman who comes to a health care centre does increase the number who acknowledge they have been abused by their partners, a new study confirms.
The study, led by Patricia O'Campo, director of the Centre for Inner City Research at St. Michael's Hospital, represents a major reversal of thinking about the value of universal screening programs for domestic abuse or intimate partner violence.
Until now, the research and health care policy communities felt there was insufficient evidence to support such programs. O'Campo reviewed ...
LAST 30 PRESS RELEASES:
Biodegradable PET alternative bioproduced at unprecedented levels
NTU Singapore scientists develop cooling sunscreen from pollen
Efficient ethane separation from natural gas using ZIF-8 slurry
Flying blind: aviation experts call for more pilot training amid poor general aviation safety record
Unraveling the complex relationship between trade openness and carbon emissions in Asia
Towards a new era of global agricultural ecology and environmental science
Durham University scientists pioneer new drone swarm technology
New research reveals insights into linkage between menopause and cardiovascular health
Durham University scientists map stress response system in plants
Weight-loss drug semaglutide reduces cocaine use in rats: Suggests possible first pharmacological treatment for human cocaine dependency
Are probiotics worth the cost to prevent infection after a colon removal surgery?
Mizzou at the forefront of using hydrogen energy safely
New design framework makes it easier to create custom shock-absorbing materials
Ochsner Health honored by AMA for Joy in Medicine
New meta-analysis demonstrates that access to the GeneSight test can significantly improve response and remission rates for patients with depression
UCLA receives $7.1M federal grant to expand psychotherapy treatment for chronic pain
One dose of antibiotic treats early syphilis as well as three doses
Researchers identify single antibody behind life-threatening reaction to common blood thinner
Don’t sweat it: New device detects sweat biomarker at minimal perspiration rate
Not so sweet: Some sugar substitutes linked to faster cognitive decline
Antibody-making cells reveal new function in response to flu infection
CCNY physicists make quantum emitter discovery in diamonds
SwRI and Copeland win R&D 100 Award for innovative oil-free compressor
Loneliness is bad for health and wealth in the U.K.
Oral health treatment in patients due for surgery is associated with significantly lower rates of postoperative pneumonia and shorter hospital stays, per observational study in one Japanese hospital,
Oxygen came late to ocean depths during Paleozoic
Among women suffering hyperemesis (extreme nausea and vomiting) in pregnancy, half report considering terminating their pregnancy, and 9 in 10 have considered having no more children
Loneliness is bad for health and wealth in the UK
Climate change is making rollercoaster harvests the new normal
Misdirected: Increased dementia risk associated with errors of the 'brain’s compass'
[Press-News.org] Accurate measurement of radioactive thoron possible at lastPTB develops first primary standard worldwide for calibration of thoron measuring instruments