Endeavour shuttle to deliver giant window to ISS

The Endeavour space shuttle will fly with six astronauts aboard The US shuttle Endeavour is preparing to lift off from the Kennedy Space Center in Florida. The pre-dawn launch on Sunday will be the last time the orbiter climbs into dark skies. Just five shuttle flights remain before the re-useable fleet is retired at the end of the year. The mission to the International Space Station (ISS) will deliver a connecting unit and a large bay window that will be used as a robotic control room. The launch is timed for 0439 local time (0939 GMT). Weather forecasters say there is an 80% chance of favourable conditions. The shuttle mission is the first since President Barack Obama announced a new vision for US space exploration. Last Monday, he cancelled the rockets and capsule Nasa was developing to replace the shuttle, and urged the commercial sector to provide future transport needs. NODE 3 - 'TRANQUILITY' Key unit connects and helps manage other ISS modules Multiple docking ports for visiting vehicles or future modules 7m by 4.6m; a mass of 14 tonnes, but will be fitted out in orbit Sophisticated life support systems will include air cleaning unit Cupola to be fixed to an Earth-facing port once in orbit Panoramic views provide ideal control room for robotic arm Named after Sea of Tranquility, the Apollo 11 landing site Endeavour's mission, which includes three spacewalks, will end construction on the Western part of the space station. Once installed, the Node 3 and Cupola modules will make the platform 90% complete. The mission is an important moment for the European Space Agency's (Esa) contribution to the ISS project. Both modules being ferried to orbit were constructed in Italy by Thales Alenia Space. Their production concludes a barter arrangement made between Esa and Nasa in which Europe agreed to supply significant components for the platform in return for a free trip into space for its Columbus science laboratory and supporting equipment. Some 7m in length and about 4.5m in width, Node 3 is built around the same design principles as Europe's other space station contributions. Columbus, Node 2, the ATV space freighter, and the Multi-Purpose Logistics Modules (which serve as the packing boxes for major re-supply missions carried out by the US shuttle) all have a similar cylindrical look about them. Node 3 has several bays inside its multi-layer, meteoroid impact-hardened shell. These bays will quickly become filled in orbit by equipment already on the station. Chief among these will be the Environmental Control and Life Support Systems (ECLSS). Their jobs involve scrubbing the air of carbon dioxide to maintain its oxygen concentration; and recycling waste water, including urine, so it can be drunk again and again. Node 3 will also store a treadmill the crew will need to use regularly to exercise their bodies and maintain bone density. The node has several berthing ports that could conceivably even allow the ISS to be expanded one day. "Node 3 is an interconnecting module," explained Simonetta Di Pippo, Esa's director of human spaceflight. "It's a door open to the future, because if we decide to develop new modules, new extensions, new capabilities, we will be able to do it because we are now launching Node 3." The Cupola is a dome-shaped module with seven windows. At 80cm in diameter, its top window will be the biggest ever flown in space. UK-born astronaut Nicholas Patrick will perform three spacewalks The module will act as a control room to direct robotic operations on the exterior of the platform, and provide a vantage point for the astronauts to view their home planet. The UK-born American astronaut Nicholas Patrick will be one of the spacewalkers who will help install the modules. "I will be undoing the bolts that hold the Cupola shutters down," he said. "Once those 21 bolts are released, one of my colleagues on the inside can open up the window shutters and take a first look out through the Cupola windows, which will be, I think, just a fantastic thing on the space station," he told BBC News. This will be the 130th space shuttle flight, the 24th flight for shuttle Endeavour and the 32nd flight to the station. Nasa hopes to run out the final four shuttle flights before the end of the year, although President Obama has promised the agency funding to support the schedule should it slip into 2011.

Auklets and penguins: birds use feathers 'to touch'

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A whiskered auklet feels in the dark Birds may use their feathers for touch, using them to feel their surroundings just as cats use their whiskers. The revelation that feathers have this hitherto unknown function comes from research on auklets, birds that sport prominent plumes on their heads. Auklets with bigger crests, that stick out further, bump into things less. A wider analysis suggests that numerous birds, from parrots, penguins, pheasants and hummingbirds, also use their feathers to feel their way. Details Many species of bird sport elegant long feathers, either crests, beards or whiskers that adorn the head and face, or striking tail feathers. Many of these feathers are thought to have a sexual function, being used to advertise a bird's virility to potential mates. But Dr Sampath Seneviratne of the University of British Columbia in Vancouver, Canada and Professor Ian Jones of Memorial University in St John's, Canada suspect they may also have a tactile function. Bumping heads They explored why a group of birds called auklets have evolved such elaborate head feathers. Within the genus Aethia, a number of species have different shaped feathers, but both males and females tend to look the same. The birds usually breed in dark, rocky crevices. BEAUTIFUL BIRDS: FIND OUT MORE Many bird species have 'silver' wings, a sheen created by a hitherto unknown structure in their feathers, scientists recently discovered Crested penguins, including rock-hoppers and macaroni penguins, all have tufts of yellow feathers on their heads Many birds such as the spatuletail hummingbird, seen here on video, have long ornamental tail feathers which they use to advertise their prowess The researchers placed individual auklets into a dark experimental maze, designed to resemble a natural crevice, and recorded how often they bumped into things. Both crested and whiskered auklets bumped their heads 2.5 times more often if their feathers on their heads had been artificially flattened. Also, "without the aid of the crest, naturally long-crested individuals had more head bumps than short-crested individuals," Dr Seneviratne told the BBC. The two ornithologists then conducted a wider comparative analysis: checking which bird species sport long ornamental feathers against their lifestyles and where such birds live. What emerged was a striking pattern. "Birds that live in complex, cluttered habitats and are active at night tend to have a greater probability to express such facial feathers," says Dr Seneviratne. "We found a highly significant correlation for the observed trend." Penguins to parrots The pattern held true across all non-passerine birds, which comprise about half of all bird species. The researchers did not include passerine, or perching birds, in their analysis. That means that various species of penguin, parrot, cormorant, owl, hummingbird, kingfisher, woodpecker and game birds such as partridge and pheasant, may all use certain feathers for touch. Such species have facial feathers variously called crests, beards, whiskers, rictal bristles and orbital plumes. Touching moment Dr Seneviratne and Prof Jones suspect that similar feathers, such as the long streamers found on birds of paradise or the pin and forked tails of other species, and even protruding feathers on some birds' wings, may fulfil a similar function. Biologists have long wondered and debated why birds have long ornamental feathers. Many do so for camouflage, as a warning to startle predators, or to advertise their prowess. For example, "long facial feathers are generally thought to be 'sexy ornaments' used to seduce choosers and for assessment of the presenter," says Dr Seneviratne. Cat's whiskers But while such feathers may have acquired these functions, their original purpose may have been to provide a similar function as a cats' By providing sensory feedback to a bird about its environment, such feathers can provide a distinct advantage, particularly to birds living in dark or crowded environments. "Birds living in complex habitats are likely to encounter greater density of objects or clutter that they have to avoid." So such feathers could help birds avoid bumping into burrow ceilings, tree branches and undergrowth. Feathers around the face would prove especially useful, as they might stop a bird damaging vital organs, such as eyes, eardrums, nostrils and bill. "We describe the first comparative evidence for this widespread but entirely overlooked sensory function of long facial feathers. "We argue that this provides a hitherto missing explanation for the origin of ornamental feathers," says Dr Seneviratne. or a blind person's cane. the discovery are published in the journal Animal Behaviour.

Sperm sprint secrets 'may lead to new contraception'

Sperm need to delay their frantic dash until they are close to the egg A mechanism which starts sperm swimming when they get near the egg could one day lead to new forms of male contraception, scientists have said. Tiny pores on the sperm's surface allow it to change its internal pH, which in turn starts its tail movements. Researchers from the University of California in San Francisco said the study might also explain why marijuana makes men infertile. A UK expert said it could have a big effect on men's fertility. Limited resources Sperm do not start swimming from the moment of ejaculation - they have only limited resources, and to stand much chance of reaching the egg, need to delay their frantic dash until they are closer to the egg. Scientists have long known that a sperm's level of activity is governed by internal pH - how acid or alkaline its contents are - but the method which alters this at the right moment has proved elusive. In order to increase its pH and become more alkaline, the sperm needs to jettison protons, and the US scientists have found pores on its surface which allow it to do precisely that. Dr Yuriy Kirichok, who led the research, said: "The concentration of protons inside the sperm cell is 1,000 times higher than outside. "If you just open a pore, protons will go outside - we identify the molecule that lets them out." These pores, or Hv1 proton channels, as they have been termed, seem to be primed to open at precisely the right moment. They respond to a substance called anandamide, which is present in the female reproductive tract, and in particularly high levels near the egg. Cannabis theory Anandamide is an "endocannabinoid", a natural substance which can affect neurons, but it is possible that the cannabinoids found in marijuana may mimic some of its effects - which could explain why cannabis use has been associated with subfertility in men. Dr Kirichok said: "Marijuana likely activates sperm prematurely, leaving them burnt out in a matter of hours." He said that it was possible that the newly discovered channel could be exploited by a drug which hampered the proton release, leaving sperm stranded. He said: "All of these events are essential to fertilisation - you can imagine now that we know the molecule responsible we could block it to prevent activation and fertilisation as a kind of male contraception." Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said: "Although it seems obvious that sperm have to swim in order to find and fertilise an egg inside the female body, or in the dish during IVF, we are only just uncovering some of the molecular details that the sperm use when swimming" "Now that we know what this ion channel is, then it could lead us to either develop a novel contraceptive for men, or perhaps find a way to improve the sperm motility for men whose sperm don't swim as well as they should"

MRSA superbug strain 'tracked' via genome

The appearance of MRSA has been linked to widespread antibiotic use

Researchers have developed a technique for precisely tracking the spread of the superbug MRSA in hospitals.

The team from the Wellcome Trust Sanger Institute in Cambridge looked at the genomes of MRSA strains from across the globe and at one hospital in Thailand.

They were able to spot small changes that allowed them to track the strain back to an individual patient.

They say this adds to the understanding of how MRSA can spread so rapidly and should lead to better treatments.

DNA sequencing

The research, which is published in the journal Science, involved teams in the UK, Thailand, Portugal and the United States.

Scientists used new high-throughput DNA sequencing technologies to compare MRSA samples from patients to show how they were genetically related.

They were able to spot single-letter differences in the genetic code.

They looked at two different sets of samples: one set taken from people across the globe and another from a single hospital in Thailand.

They sequenced the entire genomes of each sample.

In the hospital setting it revealed single letter genetic changes in the samples showing that no two infections were caused by entirely identical bacteria.

This allowed them to discover whether one patient had infected another or whether the infection had come in from another source.

They found that the MRSA strain studied acquired about one single-letter change in its genetic code every six weeks.

Worldwide search

They also looked at samples from hospitals in several parts of the world collected over more than 20 years.

The rate of mutation apparently supports the theory that MRSA emerged in the 1960s at the time of widespread antibiotic use.

Professor Sharon Peacock, a microbiologist at the University of Cambridge said: "The implications for public health are clear. This technology represents the potential to trace transmission pathways of MRSA more definitively so that interventions or treatments can be targeted with precision and according to need."

Researchers say it would be too expensive to use the technology widely at present but the cost should fall in the next few years.

Professor Mark Enright, an expert in molecular epidemiology at Imperial College, London, said the work gave researchers "a good idea as to how this particular type of MRSA has evolved and how it behaves in and out of hospitals".

"This work is a great demonstration of new, rapid DNA sequencing that in the near future will be how important pathogens such as MRSA will be identified," he said.

"Such unambiguous identification will form the basis for rapid diagnostics of microbial infection and will tell us how they spread in hospitals identifying each human host and surface in chains of transmission between patients."

Alligators and birds share lung structure and ancestor

How do alligators breathe?

Alligators and birds share a breathing mechanism which may have helped their ancestors dominate Earth more than 200 million years ago, scientists say.

Research published in the journal Science found that like birds, in alligators air flows in one direction.

Birds' lung structure allows them to breathe when flying in low oxygen, or hypoxic, conditions.

This breathing may have helped a common ancestor of birds and alligators thrive in the hypoxic period of the Triassic.

Mammals 'hiding'

"It might explain a mystery that has been around for quite some time", Dr Colleen Farmer from the University of Utah told BBC News.

The mystery in question is why the archosaurs came to dominate Earth after the planet's worst mass extinction 251 million years ago.

Archosaurs evolved into two different branches which developed into crocodilians, dinosaurs, flying pterosaurs and eventually birds.

Synapsids, which evolved to include mammals, had been dominant in the Permian period before the mass extinction.

Some survived but were toppled from their perch by the archosaurs.

Any mammal-like synapsid survivors "were teeny liittle things hiding in cracks" said Dr Farmer. "I think it's because they couldn't compete.

"It wasn't until the die-off of the large dinosaurs 65 million years ago that mammals made a comeback and started occupying body sizes larger than an opossum."

To demonstrate alligator lung mechanisms, the scientists measured airflow in anesthetised animals, showing it flows in one direction rather than in and out of chambers.

They also pumped water containing tiny fluorescent beads into the lungs of dead alligators to observe the flow.

Studies on these alligators may explain why some animals ruled the Earth.

Puzzle solved

The researchers believe the similarity in lung structure may explain why some animals were better able to adapt after the extinction, when oxygen levels dropped.

"We know that birds are really good at breathing in hypoxic conditions. They can fly at altitudes that would kill a mammal," said Dr Farmer.

"Many archosaurs, such as pterosaurs, apparently were capable of sustaining vigorous exercise. Lung design may have played a key role in this capacity.

"That's been a puzzle, why do birds have these very different lungs? But now we can date it back to the common ancestor of birds and crocodilians.

"It implies that all dinosaurs, herbivores like Triceratops and carnivores like Tyrannosaurus, had bird-like lungs," Dr Farmer added.

New strategies may cut screening errors, says US study

Radiographers look for abnormalities among many normal cases

US scientists have found a way they believe may cut the number of mistakes made by medical staff looking for breast and cervical cancers.

Writing in the journal Current Biology, the researchers say that people in all walks of life looking for rare events often miss them.

But accuracy improves if people first get used to looking at samples of what they need to find.

Screening professionals said it was a recognised problem.

They carried out a study which showed that the number of mistakes made during a visual search varied according to the chances of finding the "target".

Time searching

Twelve volunteers were asked to identify target items in X-ray images of assorted objects in empty bags.

The accuracy of their search was monitored as the frequency of the target was altered.

The laboratory results are to be tested in clinics and airports. 

The study found that the amount of time the observers spent looking for something depended on how often if appeared.

"If you don't find it often, you often don't find it," said lead author, Jeremy Wolfe of Harvard Medical School.

"If you are trying to find 20 cases of breast cancer from 40 mammograms, you'll find more of them than if you look for the same 20 cases from 2,000 mammograms.

"From an evolutionary point of view it makes sense for people to give up searching more quickly if they don't expect to find what they were looking for," he said.

"If you know berries are there, you keep looking until you find them. If they are never there, you don't spend your time hunting."

But this causes difficulties when the aim is to accurately spot rare phenomenon like cancers or bombs in travellers' luggage.

Instant feedback

The authors say that one benefit of staff doing a booster exercise before starting work is that it helps them to visualise what they are looking for and improves their search success rate in the subsequent session.

They say that this kind of exercise could also sharpen search skills by providing instant feedback.

In the real world it often takes many months for radiographers and radiologists to discover if they have made mistakes.

The research has been welcomed by the Society of Radiographers.

Chief executive Richard Evans said: "The difficulty of spotting abnormal results among large numbers of normal cases is a recognised problem.

"I look forward to seeing more details about this research, but radiographers would welcome techniques which help ensure the best possible standards."

He pointed out that the NHS already monitors the performance of everyone involved in breast screening through a regular audit.

Italian scientists' 'wood to bone' medical breakthrough

Scientists in Italy have discovered a way of making artificial replacement bones out of wood.

Early trials on sheep have showed encouraging results.

The team behind the programme hopes the new bones will soon be available for patients whose own bones have been damaged by accident or disease.

Coloured lasers may offer a way to treat epilepsy

Laser lights can control cell signalling

Coloured lights could be used to find treatments for brain disorders such as epilepsy, a study has suggested.

A Massachusetts Institute of Technology team discovered a way to shut down brain activity using flashes of yellow and blue lasers.

They hope to adjust this to switch off neurons that generate an electrical impulse abnormally, causing seizures.

This could help experts understand how the brain works and, ultimately, offer treatment targets, Nature reports.

The work relies on two genes found in natural organisms like algae that need light to make energy.

Illuminating

These genes, known as Arch and Mac, contain the genetic code for light-activated proteins.

The MIT team engineered brain neurons to express Arch and Mac.

By doing this, they were able to control the brain cells of mice and monkeys using light.

Light activates proteins which, in turn, lowers the voltage in the neurons and prevents them from generating an electrical signal, known as firing.

Arch responds to blue light, Mac to yellow, and both recover afterwards.

Now the researchers plan to closely examine the neural circuits of the brain in the lab to find targets that, when shut down, could treat epilepsy as well as other conditions including Parkinson's disease and chronic pain.

Ed Boyden, who led the research, said: "Silencing different sets of neurons with different colours of light allows us to understand how they work together to implement brain functions.

"These tools will help us understand how to control neural circuits, leading to new understandings and treatments for brain disorders."

Although the work has involved animals, it should shed light on what is happening in humans, he said.

Professor Gero Miesenbock of Oxford University has been using the same technology in his research, which has included studying memory formation in fruit flies.

He has said the technology is "beginning to yield previously unattainable insight" into the organisation and regulation of the neural circuits of the brain, and the link between patterns of cellular activity and behaviour.

Biological cells reveal brain chemistry secrets

The cells change colour to reveal specific kinds of neural messages

Scientists have developed biological cells that can give insight into the chemistry of the brain.

The cells, which change colour when exposed to specific chemicals, have been used to show how a class of schizophrenia drug works.

The researchers hope they will also help shed light on how many other drugs work on the brain.

The study, by the University of California - San Diego, is published in Nature Neuroscience. 

Schizophrenia is most commonly associated with symptoms such as delusions and hallucinations.

But people with the illness also struggle to sustain attention or recall information.

A class of drugs called atypical neuroleptics has become commonly prescribed, in part because they seem to improve these problems.

However, the way they altered brain chemistry was uncertain.

It was known that the drugs trigger the release of a large amount of a chemical called acetylcholine, which enables brain cells to communicate with each other.

However, the drugs have also been shown to hobble a receptor on the surface of the receiving cell, which would effectively block the message.

The San Diego team designed biological cells - called CNiFERs - which changed colour when acetylcholine latched onto this particular class of receptors - an event scientists have not previously been able to detect in a living brain.

They implanted the cells into rat brains, then stimulated a deeper part of the brain in a way known to release acetylcholine nearby.

In response, CNiFERs changed colour - proving that they were working.

They then gave the rats one of two atypical neuroleptics. In both cases the drug severely depressed the response from the CNiFERs.

This suggested that the drugs' receptor-blocking action over-rides the increase they trigger in acetylcholine.

Researcher Professor David Kleinfeld said the new cells had great potential to reveal the mysteries of chemical action in the brain.

He said: "It's a world of signalling between cells that we were blind to before."

The researchers say they are already working to redesign CNiFERS so they can detect the activity of other types of receptors as well.

Paul Corry, of the mental health charity Rethink, said: "This study shows the value of mental health research.

"It is eliciting new information that could lead to the development of more effective drug treatments for schizophrenia, which have fewer of the debilitating side-effects associated with even the most modern atypical medicines.

"That in itself would benefit millions of people around the world.

"But the research also offers a new technique for understanding the workings of the brain that could also be developed for use across broad areas of medicine.

"We really do need to recognise that mental health research is starved of funds compared to other areas of medicine and recognise also that much of it takes place at the frontiers of our understanding which means that results from it could have far-reaching applications."

Tasmanian devil facial cancer origins 'identified'

Since the mid-1990s, Tasmanian devil numbers have crashed

Researchers believe they have identified the source of fatal tumours that threaten to wipe out the wild population of Tasmanian devils.

Writing in Science, an international team of scientists suggest cells that protect nerves are the likely origin of devil facial tumour disease (DFTD).

The disease is a transmissible cancer that is spread by physical contact, and quickly kills the animals.

DFTD has caused the devil population to collapse by 60% in the past decade.

"To look more closely at the tumours' origin, we sequenced the genes that are expressed in this devil cancer and compared them with other genes that are expressed in other devil tissues," explained lead author Elizabeth Murchison, from the Australian National University in Canberra.

She told the Science podcast the team's findings delivered surprising results.

"We found that the tumours expressed genes that were normally only expressed by Schwann cells, which are cells that are found in the peripheral nervous system that protect nerves."

'Genetically distinct'

The researchers sampled 25 different tumours from all over Tasmania, the only place on the planet where the world's largest carnivorous marsupials are found.

DEVILS IN DETAIL Scientific name: Sarcophilus harrisii Devils were given their common name by early settlers, who were haunted by "demonic growls" Largest living carnivorous marsupial Now only found in Tasmania Can live up to five years in wild Weight: male 10-12kg; female 6-8kg They favour habitats where they can shelter by day and scavenge by night

They found that the growths were genetically distinct from their hosts, but were identical to one another.

Dr Murchison, who is also a researcher at Cold Spring Harbor Laboratory, US, said the teams findings had a number of positive outcomes: "Most importantly, this has led to the development of a diagnostic test for the disease.

"Devils are susceptible to a number of different types of cancer. Just like humans, they can get breast cancer, leukaemia, etc - especially in their old age.

"Sometimes it can be difficult to tell the difference between these types of cancer and the transmissible disease.

"Now that we know that these very specific Schwann genes are expressed in the cancer, we can use these genes as diagnostic markers."

DFTD was first described in the mid-1990s, when devils with large facial tumours were photographed in north-eastern Tasmania.

By the end of 2008, the disease - which kills infected animals within nine weeks - had been confirmed at 64 locations, covering more than 60% of the Australian island state's mainland.

Experts warn that without intervention, the disease could wipe out the wild population of the world's largest carnivorous marsupial within decades.

Dr Murchison hoped identifying the catalogue of genes associated with DFTD would lead to the development of vaccines, or possibly therapies.

The disease usually kills infected devils within nine weeks

"As yet, unfortunately, there is nothing we can do to help the devils that have the disease," she said.

"This devil facial cancer is very unusual as it is an infection cancer; it is a little bit like an organ transplant," she said.

"In an organ transplant, you have an organ that is transplanted into an unrelated individual. In the case of the devil cancer, you have a cancer that is transplanted into another unrelated devil through biting.

"One of the big questions about this cancer is why it is not being rejected or being recognised as a foreign graft.

"If we could understand that... we could perhaps use this data to develop a vaccine that could help the devils' immune system reject the cancer before it takes hold."