S& T 16,2

Signature of radiation induced thyroid cancer
It is now possible to discriminate between cancers caused by intake of a radioactive material and those that arise spontaneously

Ready evidence: The study was successful because the researchers had carefully collected, documented and stored samples of thyroid cancer tissues from the Chernobyl region in the Chernobyl tissue bank.
Recently, scientists from the Helmholtz Zentrum Munchen have identified a genetic change in thyroid cancer as a signature or fingerprint that points to a previous exposure of the thyroid to ionizing radiation. They discovered the gene marker in papillary thyroid cancer cases from the victims of Chernobyl; this marker was absent in the thyroid cancers in patients with no history of radiation exposure.
This breakthrough has profound biological significance. Now, for the first time, scientists have been able to discriminate between the cancers caused by the intake of a radioactive material and those that arise spontaneously.
Cancer occurence
Most cancers occur spontaneously or when cells get exposed to certain viruses or chemicals or a physical agent such as ionizing radiation. So far, there was no way to identify uniquely a radiation cancer from a naturally occurring cancer.
The researchers led by Prof Horast Zitzelsberger and Dr Kristian Unger from the Radiation Genetics Unit of the Helmholtz Zentrums Munchen in collaboration with Prof. Geraldine Thomas, Imperial College London, examined the thyroid cancers from children exposed to the radioiodine fallout from the accident at the Chernobyl nuclear power station.
After decay
For comparison, they looked for the same genetic change in thyroid cancers of children born more than one year after the explosion, after all radioiodine decayed away. Iodine-131 has a half life of 8 days.
Scientists found that the number of copies of a small fragment of chromosome 7 was increased only in the cancers from the irradiated children.
Writing in the May 23, 2011 issue of the Proceedings of the National Academy of Sciences (PNAS), the researchers noted that this is one of the first genetic markers that indicate a radiation aetiology of cancer.
Normally, humans have 46 chromosomes. Two copies of chromosome 7, one inherited from each parent are present in every cell. Forty one disorders are associated with genes on chromosome 7. Changes in the number or structure of chromosome 7 occur frequently in human cancers. According to National Institutes of Health (NIH), some genes in chromosome 7 may play critical roles in controlling the growth and division of cells.
“Without these genes, cells could grow and divide too quickly or in an uncontrolled way resulting in a cancerous tumour”, NIH clarified in Genetic Home Reference.
According to Professor Zitzelsberger, the availability of the genetic marker will improve both the clinical diagnosis of thyroid cancer and our understanding of how radioiodine causes the disease to develop (B ioscience Technology, May 24, 2011).
Researchers will extend the study to determine if the genetic fingerprint is able to indicate the dose required to cause cancer.
The study was successful because the researchers had carefully collected, documented and stored samples of thyroid cancer tissues from the Chernobyl region in the Chernobyl tissue bank, a unique venture to establish a collection of biological samples from tumours and normal tissues from patients for whom the cause of their disease is known as exposure to radioiodine in childhood.
The unique collection of materials made it possible for the team to compare for the first time tumours from children of the same age and regional background ( insciences.org, May 24, 2011)
The accident at the Chernobyl nuclear power station led to contamination of milk with iodine-131, a radioactive isotope of iodine. If authorities administered stable iodine promptly during the early phase, radiation dose to the thyroid would have been negligible. Stable iodine saturates the thyroid so that the gland will not receive radioactive iodine when it arrives.
Not implemented
Unfortunately, this measure was not implemented at Chernobyl. The exposed population received large doses to their thyroid; this led to a significant fraction of the more than 6,000 thyroid cancers observed to date among people who were children or adolescents at the time of the accident. By 2005, 15 of these patients died.
Thyroid cancers will not occur in Fukushima because as per emergency plan the management at Fukushima promptly evacuated the population from the affected regions and supplied stable iodine to the evacuees.
K.S. PARTHASARATHY


Wise investment in hydrographic services capacity building needed
World Hydrographic Day (WHD) is celebrated on the 21 {+s} {+t} June each year to commemorate the establishment of the International Hydrographic Organisation (IHO) at Monaco in 1921 by Prince Albert, an ardent Oceanographer. IHO is an inter governmental consultative and technical organization and recognized as a competent international authority on hydrography and nautical charting services.
Every activity at sea
These are executed through more than 25 strict IHO Standards by the 80 member states, which has ensured uniformity in the sea sapping and related subjects.
Hydrography impinges on every activity at the sea, the most important being provision of nautical charts and publications for worldwide navigational safety with 24 X 7 updating service under the IMO /IHO/UN Conventions. Major impact of hydrography is on navigational safety, offshore maritime development (Oil/Gas/Energy/Fisheries/Minerals/Tourism/Environment) and coastal zone management, to name a few. IHO has estimated that the cost benefit ratio for investment in hydrography as a national service is 1:10.
Hydrography is the branch of applied sciences which deals with the measurement and description of the physical features of oceans, seas, coastal areas, lakes and rivers. It also seeks to provide prediction of their change over time, for the primary purpose of safety of navigation and in support of all other marine activities.
These include economic development, security and defence, scientific research, and environmental protection.
Hydrographic surveying is a top notch profession for development of any maritime nation. This along with the “National Spatial Data Infrastucture” organization has provided “mountains to deep seas” seamless data base. Now, there is an imperative need to dovetail the established hydrographic training facilities at the National Institute of Hydrography at Goa. Also this need is felt in the private sector to cover offshore human resources needs of the hydrographic industry as well and evolve credible dissemination methodology to the end users.
Vast improvements
It is significant that the hydrographic technology is seeing vast improvements, both in hardware and software terms, especially in the management of voluminous 3D digital data. Keeping hydrographic experts current in their profession is a necessity to meet many user needs.
Marine Cartography to international Standards will enable the Nation to translate the voluminous processed 3D field survey data into many user-friendly nautical products and services.
The modern equipment fit in the new catamaran design six survey vessels, coupled with well trained manpower, will enable the Indian National Hydrographic Office (INHO), to achieve 100 per cent insonification with 3D surveys within the Indian Exclusive Economic Zone. This is possible even if requested for foreign waters, with products and services to meet end users' needs with better revenue earnings.
INHO has a great responsibility on their shoulders and duty to perform on hydrography and related fields, on which some key resources shall come from the Indian juridical waters, since “the 21 {+s} {+t} century will be the Century of the Seas”.
Wise investment on hydrographic capacity building (assets and human resources ) by the Indian Government is needed.
Autonomous status
This should be coupled with a restructured autonomous status for the INHO for more effective functioning in predominantly civil applications oriented domain. These measures shall facilitate higher professionalism and profound strategic and economic returns in the years to come.
K.R. SRINIVASAN



While other migratory birds take advantage of many possible stopovers en route to rest and feed, great snipes fly the distance almost nonstop, Klaasen said.

Technology to utilise automobile exhaust

New technology is being developed to capture and use the low-to-medium grade waste heat that is going out the exhaust pipe of automobiles, diesel generators, factories and electrical utilities.


Tapping into plants to combat climate change
The photosynthetic antenna of plants absorbs the sunlight used in photosynthesis. It is an incredibly efficient mechanism, which if harnessed, can lead to more efficient solar energy, and fight against climate change.

Species expansion, exit must both be studied
As species disappear or are made extinct, many species expand their range as a result of human introduction and because certain species benefit from climate change. The two phenomena must be studied at the same time.

Volcano spews ash, gas in a plume 10 km high

A huge plume of sulphur dioxide spewed from Chile's Puyehue-Cordón Caulle Volcanic Complex, which lies in the Andes. On 4 June, a fissure opened, sending a towering plume of volcanic ash and gas over 10 km high.


new way called flash processing that makes steel 7 per cent stronger than any steel on record in less than 10 seconds has been found. The new steel is stronger and more shock-absorbing than the most common titanium alloys


GAGAN – making GPS more accurate
N. GOPAL RAJ
Use of GPS in civil aviation demands higher accuracy and reliability in determining position than a mobile phone user would need

Space sojourn: India's GSAT-8 satellite being checked prior to launch from the European spaceport at French Guiana in South America.-PHOTO: ARIANESPACE
These days, anyone who wants to find out exactly where they are can turn to their mobile phones. Phones that pick up signals from orbiting U.S. Global Positioning System (GPS) satellites are now commonplace. The phone uses that information to work out the location and display it on a map.
In a similar fashion, the GPS signals can be used to assist aircraft during take off and land as well as in flying shorter routes to their destination.
But, as there can be hundreds of passengers in a single aircraft, the use of GPS for such purposes in civil aviation demands higher accuracy in determining position than a mobile phone user would need as well as greater reliability in doing so.
One important way to meet the demands of civil aviation has been through what is known as a Satellite-Based Augmentation System (SBAS). Satellites in geostationary orbit, where they match the earth's rotation and therefore remain over the same place on the globe, are used to supplement the GPS signals.
The first such SBAS was the U.S. Wide Area Augmentation System (WAAS) that became operational in 2003. The European Geostationary Navigation Overlay Service (EGNOS) began working in October 2009 but was officially declared available for aviation use only in March this year. The Japanese have a system known by the acronym MSAS.
India is establishing its own system, the 'GPS Aided Geo Augmented Navigation' (GAGAN), a joint effort by the Indian Space Research Organisation and the Airports Authority of India.
The ground segment for GAGAN, which has been put up by the U.S. company Raytheon, has 15 reference stations scattered across the country. Two mission control centres, along with associated uplink stations, have been set up at Kundalahalli in Bangalore. One more control centre and uplink station are to come up at Delhi.
The space component for it will become available after the GAGAN payload on the GSAT-8 communication satellite, which was launched recently, is switched on. This payload was also on the GSAT-4 satellite that was lost when the Geosynchronous Satellite Launch Vehicle (GSLV) failed during launch in April 2010. Two more satellites carrying the same payload are to be launched in the coming years.
The reference stations pick up signals from the orbiting GPS satellites. These measurements are immediately passed on to the mission control centres that then work out the necessary corrections that must be made. Messages carrying those corrections are sent via the uplink stations to the satellites in geostationary orbit that have the GAGAN payload. Those satellites then broadcast the messages. SBAS receivers are able to use those messages and apply the requisite corrections to the GPS signals that they receive, thereby establishing their position with considerable accuracy.
But as with any SBAS, GAGAN needs to do more than simply provide the corrections. Not less important is ensuring the system's integrity. “Integrity is a measure of trust that can be placed in the correctness of the information supplied by the total system,” observed S.V. Kibe, who was at the ISRO Headquarters till his retirement.
It included the ability to provide timely and valid warnings to the users when the navigation system was not performing as required, he noted in article on the GAGAN system published in a recent issue of the specialist magazine Coordinates.
Currently, aircraft from must fly from one place to another along predefined air routes marked with ground-based navigation aids. Planes with SBAS receivers will, on the other hand, be able to take shorter routes, saving both time and fuel.
To help pilots land their aircraft in bad weather and poor visibility, several airports in the country are equipped with ground-based Instrument Landing Systems (ILS). Such ILS equipment is expensive. Consequently, even in airports that have it, only one runway and that too one end of a runway may have the ILS capability.
An SBAS, on the other hand, can provide guidance on both ends of all runways that fall within its coverage area. The U.S. Federal Aviation Administration (FAA) has, for instance, published the approach procedures that aircraft equipped to receive the WAAS signals can use to access 2,300 runways in over 1,200 airports in poor weather conditions.
“WAAS will provide an equivalent level of precision approach service to that of the Category 1 ILS when fully deployed,” according to the FAA. (There are three ILS categories, with those in Category 3 being able to help aircraft land in conditions with the worst visibility.)
When GAGAN becomes operational, it would provide close to Category 1 services across much of India, observed one official associated with the project. In due course, the Indian system would be upgraded and improved to meet Category 1 requirements.
During the technology demonstration phase when GAGAN was tested in 2007 with just eight reference stations and a leased transponder on the Inmarsat 4F1 satellite, the position given by a stationary SBAS receiver during a 24-hour period varied by only two metres to three metres. An ordinary GPS receiver, on the other hand, varied by as much as eight metres to 20 metres during the same period. Moreover, when aircraft fitted with SBAS receivers were flown, the GAGAN was found to provide very good position accuracies.
Once the GSAT-8's GAGAN payload becomes available for use, the full system can be thoroughly tested. However, certification of the system for safety-critical use in aviation will be taken up only only after the second GAGAN-equipped spacecraft becomes operational. The certification will be carried out by the Directorate General of Civil Aviation.
Since all augmentation systems follow common standards laid down by the International Civil Aviation Organisation, aircraft with SBAS receivers can use any of those systems.
India's GAGAN has a reach well beyond the country, from Africa and Middle East on one side to the Bay of Bengal and South-East Asia on the other other. It will therefore fill a gap between Europe's EGNOS and Japan's MSAS systems.
Moreover, as has already happened with GPS receivers, the uses for GAGAN will no doubt go well beyond aviation. Those involved in surveying and map-making will obviously benefit from the better accuracy it provides, as can the transportation sector and marine operations, not to mention recreational applications.


Radiation dose limit for eye lens slashed
The lens of the eye is one of the most radiation sensitive tissues in the body. If the eye lens which is normally crystal clear receives a high enough radiation dose it may become partly cloudy or totally opaque depending on the dose. Radiation protection agencies have prescribed dose limits to the lens to prevent induction of lens opacity or cataract.
On April 21, this year, the International Commission on Radiological Protection (ICRP) which issues recommendations on radiation protection, slashed the dose limit for the lens of the eye to 20mSv in a year, averaged over defined period of five years, with no single year exceeding 50 mSv.
Earlier dose limit
The earlier dose limit was 150mSv in a year. (Sv is a unit of biologically effective dose. The radiation energy absorbed in a sievert (Sv) is one Joule per kilogramme of material; since the unit is large, a sub-multiple such as one thousandth of a Sv or milliSv —mSv — is normally used).
Several studies over the past few years led the Commission to reduce the dose limit steeply.
There are three main forms of cataract depending on its anatomic location in the eye lens: nuclear, cortical and posterior sub capsular (PSC). Among these, PSC is the least common and is commonly associated with exposure to ionizing radiation. Radiation Effects Research foundation (RERF) describes the formation of radiation cataract thus: “There is a transparent layer of cells covering the interior frontal side of the capsule that covers the eye lens.
This layer maintains the function of the lens by slowly growing toward the centre, achieved through cell division at the periphery. Because irradiation is especially harmful to dividing cells, exposed cells at the equator are most prone to damage.
Unknown reasons
For unknown reasons, damaged cells move toward the rear of the lens before converging on the centre. Such cells prevent light from travelling straight forward resulting in opacity.”
So far, scientists believed that cataract will be formed only after the lens receives a typical radiation dose called the threshold. ICRP assumed that threshold was 2Gy for a single dose and 5 Gy when the exposure occurs in a protracted way.
Not any more. Recent studies appear to show the formation of radiation induced cataracts at much lower doses than the current standards. (Gy is the unit of absorbed dose; the dose is said to be one gray — Gy — when the ionizing radiation energy absorbed per kilogramme of material is one joule).
ICRP now considers that the threshold dose for cataract is 0.5Gy. ICRP also stated that although uncertainty remains, medical practitioners must be made aware that the absorbed dose threshold for circulatory disease may be as low as 0.5Gy to the heart or brain.
“Doses to patients of this magnitude could be reached during some complex interventional procedures, and therefore particular emphasis should be placed on optimization in these circumstances,” ICRP cautioned the specialists. The procedures include angioplasty.
The June 2010 on-line version of Catheterization and Cardiovascular Interventions and October 210 issue of Radiation Research have published studies on increased risk of cataracts among interventional cardiology professionals. Though the numbers of professionals monitored in the studies was limited, the results demand urgent action.
Chernobyl effect
Cataract analysis of 8607 Chernobyl clean up workers,12 and 14 years after exposure, indicated that posterior sub-capsular or cortical cataracts appeared in 25 per cent of the participants (Radiation Research, February 2007). Researchers found evidence of a dose threshold of less than 0.7Gy.
The researchers noted that the workloads tend to increase in catheterization suites. This, together with lack of training in radiation protection and unavailability or non-use of radiation protection accessories may result in doses to the eyes of cardiology professionals sufficient to cause cataracts.
Studies show that leaded glass alone reduced the dose to the lens by 5 to 10 times; scatter-shielding drapes alone reduced the dose rate by 5 to 25 times; using both reduced the dose rate by 25 times or more
In BioMed Central Public Health (2010), Dr Sophie Jacob from the French Institute of Radiological Protection and Nuclear Safety (IRSN) and other specialists listed 14 peer reviewed studies showing evidence for low dose radiation-induced cataracts.
The results of their study on occupational cataracts and lens opacities in interventional cardiology involving 1700 interventional cardiologists in France is expected to be available this year.
The jury is no more out on radiation induction of cataract. The present ICRP recommendations must serve as a wake up call for interventional cardiology and radiology professionals.
Raja Ramanna Fellow, Department of Atomic Energy


Wheat grown on soil with fly ash is safe
Belying apprehensions that wheat and other crops grown on fly ash mixed soil may not be safe for human consumption, research has proved that on the contrary, it has beneficial effects.
Research conducted by Hyderabad-based National Institute of Nutrition (NIN) recently cleared the concerns that fly ash disposal could contaminate soil and crops grown over it.
“Results have indicated that there is no difference between wheat samples grown in soils with fly ash and without fly ash,” Bhaskaracharya Kandlakunta, a senior scientist at NIN associated with the experiment, told PTI.
The purpose of the NIN study was to evaluate nutritional and toxicological aspects of wheat grown on soils treated with fly ash.
The results of the study were published in the Journal of Science Food and Agriculture.
Scientists carried out evaluation on rats fed with wheat grown in fly ash-applied soils.
Results showed that the moisture, protein and ash content of wheat samples showed no difference between fly ash treated and control samples, the scientist said.
The study clearly demonstrated that the shoot and root growth and yield of test crops at different locations after fly ash incorporation resulted in beneficial effects of fly ash addition in most cases. Fly ash disposal is a big environmental problem. — PTI


A new analytical method improves detection of dimethyl fumarate (DMFu) in leather and footwear. The substance causes allergic contact dermatitis. It has been detected in leather products made in Asia.


Ocean acidification will hit coral reef diversity
A new study concludes that ocean acidification, along with increased ocean temperatures, will likely severely reduce the diversity and resilience of coral reef ecosystems within this century


A widely publicized study concluded that a bacterial bloom consumed the methane discharged from the Deepwater Horizon well. Now, a recent study has shown low measured rates of methane consumption by bacteria.

New research shows that the Antarctic Circumpolar Current (ACC) played a key role in the shift in the global climate that began about 38 million years ago. Early ACC was vital to the formation of modern ocean structure.


Moving the heaven to get some rare earth

Exploration: The plan is to send rovers to the moon to look for minerals and ores which contain rare earth elements.
About a month ago came an intriguing piece of news. One Mr. Naveen Jain, who has started a company called Moon Express Inc. in California, has plans of sending robotic rovers to the moon.
These rovers will look for minerals and ores which contain rare earth elements such as Yttrium, Dysprosium, Nyobium and others, and upon finding, will send back images to the control station on earth. The team will then plan on sending space crafts to go and retrieve the rare earth minerals from the moon and bring them here.
An out-of-the-box (more an out-of-the-earth) idea! After all, recall that the moon was once part of the earth and was ejected from us (either by simple break-off from where the Pacific Ocean now is or due to collision by an external body) in the early history of the solar system. Thus, it is not unlikely that some of the ores and minerals we have here are also present on the moon; since the technology is available, why not explore there?
Why this focus on the rare earths? What are they? As many students of chemistry know, this is a group of 17 elements of the Periodic Table, specifically the fifteen of the “Lanthanide group” plus Scandium and Yttrium. Indeed, as they were discovered, they posed an embarrassment to the orderliness of the Periodic Table, much as the inert gases (also called rare gases) did. But the latter could simply be added on as an extra column (the zero group) where they fitted decorously.
But the lanthanides had to be grouped into one position with an asterisk and footnote. All the 15 elements from Lanthanum (atomic number 57) to Lutetium (atomic number 71) are placed in one spot on the table, between Barium (56) and Hafnium (72).
And they all occur together. In a given ore, for example Ytterbite which takes as name from the Swedish village Ytterby, the oxides of Yttrium and Cerium were first discovered. Further analysis revealed two more oxides, those of Lanthanum and Didymium (which itself is a twin mixture of Praseodymium and Neodymium). These Swedish ores yielded element after element, much like the Russian Matryoshka doll contains doll within a doll within a doll. The village Ytterby became famous since as many as seven elements (Yb, Er, Tb, Y, Pr and Nd) are named after it. What use are they? Because of their remarkable electronic structures, these elements and their compounds are useful in making specialty glasses, battery electrodes, superconducting materials, electromagnets, microwave resonators, and of course laser sources.
One of the most common lasers used in YAG (yttrium-aluminium-garnet), and its cousin is Nd-YAG which contains the element Neodymium also.
Other lanthanides are used in magnets, steel, MRI contrast agents and phosphors. They are ubiquitous in today's gadgets: disc-drives, miniature chargeable batteries, display, TV monitors, rangefinders, night vision goggles, and so on.
Soon it became clear that these elements and oxides are not as rare as was thought. In fact they occur just as abundantly as copper, and mostly in Brazil, China, South Africa, Malaysia US and of course India. We have rare earth ores found in Kerala and the Department of Atomic Energy has a company called Indian Rare Earths.
It is estimated that the world uses as much as 134,000 tons of rare earth metals a year, but mining only 124,000. Given this gargantuan appetite, those countries with supply are in a winning position, making rare earth stocks the new oil. And China, which holds 37 per cent of the world's supply, has decided to decrease its exports and regulate its mining efforts as well. Foreseeing the looming situation, a note has been circulated to the US policymakers by the Congressional Research Service highlighting the effect this would have on national security. Rare earth metals are used in missile guidance systems, jet fighter engines, underwater mine detectors and so forth.
Aware of the importance, India too appears to have geared up its policy. A new national multi-pronged strategy has been suggested, not only to ramp up domestic production, but also to enter into joint ventures with international players. Granted that we only offer 2% today of the world's needs, business opportunity on one hand and national needs on the other, demand such a move.
No wonder then that Naveen Jain is thinking of going to the moon. Now, if he can do it, should we not too? Moon is just as free and uninhabited as the Antarctic (just a bit farther away), and several countries have pitched their tents and hurled their flags in the latter.
And it is not the same as the colonization of The Gold Coast (Ghana) by the Portuguese and British, subjugating the native residents, or of D R Congo by the Belgians for diamond. So, are there rules for such exploitation and owning virgin territories, or is it free for all – first come first own? Are there any international laws or accepted practices? I wonder.
D. BALASUBRAMANIAN