Listen to simulations of our ancestors’ first sounds

YOU may think humanity’s first words are lost in the noise of ancient history, but an unlikely experiment using plastic tubes and puffs of air is helping to recreate the first sounds uttered by our distant ancestors.

Many animals communicate with sounds, but it is the variety of our language that sets us apart. Over millions of years, changes to our vocal organs have allowed us to produce a rich mix of sounds. One such change was the loss of the air sac – a balloon-like organ that helps primates to produce booming noises.

All primates have an air sac except humans, in whom it has shrunk to a vestigial organ. Palaeontologists can date when our ancestors lost the organ, as the tissue attaches to a skeletal feature called the hyoid bulla, which is absent in humans. “Lucy’s baby”, an Australopithecus afarensis girl who lived 3.3 million years ago, had a hyoid bulla; but by the time Homo heidelbergensis arrived on the scene 600,000 years ago, air sacs were a thing of the past.

To find out how this changed the sounds produced, Bart de Boer of the University of Amsterdam in the Netherlands created artificial vocal tracts from shaped plastic tubes. Air forced down them produced different vowel sounds, and half of the models had an extra chamber to mimic an air sac.

De Boer played the sounds to 22 people and asked them to identify the vowel. If they got it right, they were asked to try again, only this time noise was added to make it harder to identify the sound. If they got it wrong, noise was reduced.

He found that those listening to tubes without air sacs could tolerate much more noise before the vowels became unintelligible.

The air sacs acted like bass drums, resonating at low frequencies, and causing vowel sounds to merge; Lucy’s baby would have had a greatly reduced vocabulary. Even simple words – such as “tin” and “ten” – would have sounded the same to her.

Observations of soldiers from the first world war corroborate de Boer’s findings. Poison gas enlarged the vestigial air sacs of some soldiers, who are said to have had speech problems that made them hard to comprehend.

De Boer’s study provides clear evidence supporting the idea that the need to produce complex sounds to communicate better made air sacs shrink, says Ann MacLarnon of the University of Roehampton in London. More sounds meant more information could be shared, giving those who lacked air sacs a better chance of survival in a dangerous world.

“Early humans’ need to produce complex sounds to communicate better made their vocal air sacs shrink”

De Boer found that air sacs also interfered with the workings of the vocal cords, making consonants trickier. Only once they had gone could words like “perpetual”, requiring rapid changes in sound, be produced.

What, then, might our ancestors’ first words have been? With air sacs, vowels tend to sound like the “u” in “ugg”. But studies suggest it is easier to produce a consonant plus a vowel, and “d” is easier to form with “u”. “Drawing it all together, I think it is likely cavemen and cavewomen said ‘duh’ before they said ‘ugg’,” says de Boer.

Listen to simulations of the vowel sounds with and without air sacs:

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OLD oil and gas wells might soon be reborn as environmentally friendly geothermal power generators.

Geothermal energy holds promise as a low-carbon source of electricity because of its ubiquity – rock temperatures increase by between 25 and 50°C for every kilometre of depth due to heat from the Earth’s core. But as much as half the cost of geothermal power plants comes from drilling into the Earth.

Old oil and gas wells often plunge several kilometres deep to reach reserves. Refitting their shafts to circulate water could provide an easy way to extract this energy, says Xianbiao Bu and colleagues from the Chinese Academy of Sciences in Guangzho.

The team proposes a pipe-within-a-pipe design. Water would flow down one pipe to the bottom of the well, heat up and then be pumped up an inner pipe to the surface, where it would drive a turbine ().

Xianbiao believes that a typical well could produce around 54 kilowatts of electricity – not much compared to a full-sized power plant running on coal, gas or nuclear energy. But with an estimated 2.5 million abandoned oil and gas wells in the US alone, huge stores of energy could be going untapped.

The scales are actually a tiny maze of fluid-filled channels, 10 to 15 micrometres wide, sitting on a chip attached to various sensors. Computer-controlled jets direct cells around the maze until one becomes trapped in a receptacle just big enough to hold it. The receptacle sits at the end of a springboard-like channel that vibrates at specific frequencies depending on the channel’s mass. When a cell is forced into this channel it displaces some of the fluid inside. This changes the frequency of vibration, which is monitored and used to weigh the cell.

from the Massachusetts Institute of Technology and colleagues have shown that the scales are able to weigh yeast cells accurately to within a few trillionths of a gram.

Manalis’s team then used them to monitor changes in cell growth in response to drugs. First, the researchers trapped single white blood cells within the scales. They left the cells to grow for 10 minutes, then replaced the glucose fluid in the scales with one containing sodium azide – a toxic chemical that damages cell membranes – and left the cells to grow for a further 10 minutes. As the cells grew, fluid was displaced, changing the frequency of vibration of the channel, which was monitored throughout. Cells grew at a much slower rate after the sodium azide solution was added (, ).

Manalis says the scales could be used to help develop personalised cancer therapies that could be tested on an individual’s cells. “We plan to determine if the growth response of tumour cells can be predictive of how a patient will respond to a therapy, he says.

“Measuring the growth of single tumour cells may predict how a patient will respond to a therapy”

Snake oil might be best avoided but snake blood may be just what the doctor ordered. Injecting snake-blood plasma into mice increased the size of their heart. The discovery could prove key in the treatment of heart damage.

In humans, an enlarged heart is normally a sign that the body is in trouble. Heart attacks, high blood pressure and defects in heart valves all force the heart to work harder and grow to manage the extra load. Growth can scar the heart and decrease the efficiency of nutrient absorption in heart cells.

The heart of the Burmese python, a subspecies of Indian python, also grows. After eating a large meal, the organ nearly doubles in size to pump recently digested nutrients around its body. This growth, however, has no negative side effects and is reversible.

Similarly, heart growth in humans is not always negative. A hormone called insulin-like growth factor 1 (IGF-1), produced during exercise, causes the heart to swell in order to meet increased bodily demand for oxygen. When growth occurs in this way, there is no scarring.

Fatty acid cocktail

After eating, a snake’s blood contains a cocktail of fatty acids, some of which from the University of Colorado at Boulder, suspected were causing the heart to grow.

To see if this enriched blood could have the same effect on other animals’ cells, Leinwand coated in vitro rat heart-muscle cells with the blood plasma of recently fed snakes and found that they produced a greater volume of IGF-1 while also increasing in size. The cells were able to process fats more effectively and had a faster metabolism. The snake plasma also caused the rat cells to produce less NFAT – a protein created when hearts are stressed.

The team next identified three fatty acids that appeared key to these helpful effects. They injected these fatty acids into healthy mice. After one week, the hearts of these mice had increased in size and showed no sign of scar tissue.

Leinwand believes that the discovery could lead to new treatments to strengthen hearts damaged by heart attack. She now plans to test the fatty acids on mice with heart disease to see if cell death in the heart can be slowed or even reversed.

Journal reference: Science, DOI 10.1126/science.1210558

Doctors, like many others, already rely on stimulants like caffeine and nicotine to boost flagging performance, but Colin Sugden at Imperial College London and colleagues decided to test whether they could benefit from something stronger: modafinil, a drug originally designed to treat sleep disorders such as narcolepsy and sleep apnoea.

The exact way modafinil affects the brain is not known, but it is believed that it acts on specific parts of the hypothalamus responsible for keeping people awake.

After missing a night’s sleep, 39 male doctors were put into one of two groups. Sugden’s team gave one group a dose of modafinil while the other got a placebo. Both groups were then subjected to a number of cognitive tests, and asked to use a surgical training simulator to gauge their motor skills. Neither the participants nor the researchers they met knew which group received which treatment – a strategy to avoid inadvertent bias.

The doctors who had taken modafinil scored higher on the cognitive tests: they had better working memory, could plan more effectively and made less impulsive decisions – all useful qualities for a doctor. No improvements were seen in their surgical ability, however.

Docs on drugs

Some media reports of the work have suggested that it means . Sugden himself says that the research is too preliminary to make such a link.

“It is not clear how performance on tests of mental function relates to how someone performs as a doctor,” he says. “Larger studies looking at the performance effects and safety of longer-term use of the drug would need to be performed before we could draw conclusions about whether or not sleep-deprived doctors might benefit from taking it.”

If such studies find evidence that the drug could improve patient care, might doctors working long shifts be encouraged to take modafinil? Could they even face malpractice claims for failing to do so, as ?

“This was an academic piece. We wanted to encourage a debate in order to identify the ethical considerations,” says Sugden.

Clock-watching

A mean that junior doctors in the EU may not work more than 48 hours a week, and must have 11 hours of continuous rest out of 24. Previously, 60 to 100-hour weeks were been considered normal.

“[UK] National Health Service organisations should ensure staff are well rested to do their jobs properly – not replace good management with performance-enhancing drugs,” a spokesperson for the UK government’s Department of Health told ��è����Ƶ.

Surprisingly, though, it is not certain that patients suffer when doctors work long shifts. On the one hand, a showed that doctors working overnight were three times more likely to make an error leading to a patient’s death than those working on a normal schedule. On the other, a of New York state hospitals that followed the introduction of legislation to reduce working hours found there was no change in the rate of deaths from due to congestive heart failure or pneumonia.

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GO GO gadget arms! Turbines could soon sport blades that extend and retract to suit wind conditions.

Large turbines harvest more energy from the wind than small ones – provided the breeze doesn’t freshen too much. Then long blades become a disadvantage as they exert big stresses on the turbine’s mechanism, which can damage it. So turbine designers generally strike a compromise between efficiency and durability.

What about a wind turbine with telescopic arms? of the University of Auckland in New Zealand calculated that such a turbine could generate twice as much power over a year as an ordinary one, and be safe to run at high wind speeds. To test the idea, he built a prototype based on a small 1.5-kilowatt turbine. In strong winds it generated the same power as a standard turbine, while in gentler conditions it easily beat its rival.

The extendable blades cost more to make, though Sharma calculates they would be cost-effective even if they were four times as expensive as ordinary ones. The blades could be deployed in areas once thought unsuitable for wind power, Sharma adds. And existing turbines could be retrofitted with the blades, though Sharma has not tested the idea on industrial-scale turbines.

An alternative chemistry of DNA-bonded nanoparticles, rather than chemically bonded atoms, just got a boost. We now have rules for building crystals like this, which means they can be created on demand.

In nature, the atoms of different elements arrange themselves in very different ways to form crystals. How many partners each atom is bonded to, and the length of the bonds, depend on the sizes and properties of the atoms in question. So sodium chloride forms a “face-centred cubic” structure, in which each sodium atom is surrounded by six chlorines and vice versa; whereas in gallium arsenide, say, the atoms arrange themselves differently and each has only four nearest neighbours.

of Northwestern University in Evanston, Illinois, and colleagues wondered if they could wrest control from nature and create crystals where the bond lengths and number of bonds don’t depend on the size or composition of the component particles.

To do this the researchers coated their atom analogues – gold nanoparticles – with multiple DNA molecules. The DNA contained exposed, single-stranded sections that formed “sticky” regions on each particle which could bond to complementary sections on strands coating other gold particles.

It’s not the first time that researchers have used these building blocks to create artificial structures. In the past few years, structures have been build that , with the nanoparticles as “atoms” and the DNA linkers standing in for chemical bonds. A current limitation is that the identities of the particles being assembled often determine the structures that can be synthesised – so certain structures can only be built using certain nanoparticles and vice versa.

Now Mirkin and colleagues have worked out how to dictate the number of nanoparticles and the length of bonds for a system of particles of a given size and composition – and summarised their findings in six rules. For instance, the total size of the nanoparticle, including its DNA coating, determined what sort of crystal developed – and this size could be tailored either by using different lengths of DNA or different-sized nanoparticles.

Against nature

These rules could be used to design artificial crystals with totally novel properties, says Mirkin. This is “one of the most fundamental demonstrations of man over nature”, he adds.

For instance, he suggests using the rules to design materials that can absorb light of low energy and release it in the form of high-energy photons. This might drastically improve the efficiency of solar cells.

“There are extremely few successful examples of crystals with nanoparticles, and these were obtained after extremely difficult procedures and with little control over the final structure,” says of Iowa State University in Ames. “This paper shows how DNA-programmed self-assembly provides a relatively simple route to solve this very fundamental technological problem.”

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The mutant form of adult haemoglobin forms long sticky chains inside red blood cells. The cells containing these chains can clog small blood vessels, depriving organs of oxygen and causing pain. In severe cases, sickle cell disease can be fatal. Tricking the body into make fetal haemoglobin again can alleviate symptoms, though.

That’s because fetal haemoglobin does not form sticky chains. However, it is produced in the body only during development in the womb and in the six months following birth. It has a higher affinity for oxygen than adult haemoglobin, vital in allowing the developing fetus to “steal” oxygen from its mother’s blood.

of Harvard Medical School in Boston, and colleagues, knocked out the BCL11A gene from mice belonging to a strain that normally develops a sickle cell-like condition. As adults, the mice produced over 20 times more fetal haemoglobin than normal and their blood contained almost no sickle-shaped cells. Their spleen and kidneys – organs easily damaged by the effects of the disease – were almost completely healthy.

Bound and gagged

Gene therapy to block the action of BCL11A in humans could in theory provide similar benefits. Specially designed lengths of RNA, injected into the bloodstream, could bind with the BCL11A gene and silence it. This approach, however, would be expensive and impractical on a large scale. “The long-term goal is to have a drug that can effectively block the function of BCL11A,” says Orkin. “It’s a more challenging approach, but one that could be applied to large populations.”

Other treatments designed to encourage the production of fetal haemoglobin have been suggested over the years. One drug in particular – hydroxyurea – is widely used but has many side effects including reducing the levels of white blood cells.

Orkin’s main concern with hydroxyurea, however, is that its effect on the body is not fully understood. “We have no idea how it really works. In some patients it’s good, in others it doesn’t work at all. It’s unpredictable,” he says. “Our approach gets to the real mechanism. It actually silences the gene that leads to fetal haemoglobin being suppressed.”

Journal reference: , DOI: 10.1126/science.1211053

Top of the list is the idea of paying for the funerals of people who agree that their organs can be transplanted after they die.

Almost 8000 people are waiting for a transplant in the UK. Although 18 million people are signed up to the British , three people every day die waiting for a donor.

The council hopes that offering to pay funeral expenses would encourage more people to sign up. If introduced, it would be the first such scheme in the world. , a consultant transplant surgeon and co-author of the report, says a pilot study should be introduced.

The average British funeral costs nearly £7000, but a funeral-for-transplant scheme would quickly pay for itself. Kidney transplants alone a year per patient, as they remove the need for costly dialysis. Rigg says that reduced treatment after organ transplantation saved the British National Health Service more than £50 million in 2008.

Opt in or opt out?

In the UK, the donor must have explicitly given consent before their organs can be taken, but in some other countries, such as Spain, consent is assumed unless a person has registered their refusal. There have long been calls for such an opt-out system to be introduced in the UK as a way to increase donor numbers.

Opt-out systems might seem a sure-fire way of getting more organs, but the report suggests that they are not. “There is uncertainty about whether or not an opt-out system could lead to more organs being donated,” says Rigg. Although Spain has the highest rate of organ donation in the world, Sweden, which also practises opt-out, has a rate lower than the UK.

There will always be uncertainty about what the person really wanted with an opt-out system, says , a medical ethicist at Brighton and Sussex Medical School, UK. The absence of a request to opt out could be a sign of the donor being confused or misinformed about the process, rather than a willingness to donate.

Living free

The report also made recommendations about live organ donation. To prevent donors being exploited or harmed by repeat donations, it is against European law to offer payments directly for organs – and the authors say altruistic donation should remain the rule. Any additional money given over expenses could undermine the motive of helping others, they say.

For egg and sperm donations, however, they recommend that a cap of £250 for expenses should be increased to match the lost earnings of anyone willing to donate. With half of all fertility clinics in the UK short of sperm, and nearly all clinics short of eggs, no financial barrier should prevent donation, says Farsides.

Price of eggs

Women who are willing to suffer the discomforts and possible health effects of donating eggs for medical research should be paid over and above the expenses given to those donating for fertility treatment, however, the report concluded.

Participants in phase I clinical trials often receive hundreds of pounds for their involvement, says , an anthropologist who also worked on the report.

“Donating eggs for research purposes is different from donating to help someone else’s treatment. You’re not trying to help a particular individual – you are more a participant in a research exercise,” she says. A registry should be set up to ensure donations are monitored and regulated, she adds.

Prehistoric paintings in northern Spain could be irreparably damaged if plans to reopen the Altamira cave to tourists go ahead. Local officials want to reopen the cave to boost the local economy, but visitors could heat the caves and introduce microbes that destroy pigments.

The were discovered in 1879 and are thought to be at least 14,000 years old. The paintings have attracted huge numbers of visitors – 175,000 in 1973, the busiest year on record. But the cave was closed to the public in 2002 after photosynthetic bacteria and fungi were found to be consuming pigments at alarming rates.

Plans to reopen the caves could restart the damaging processes. A team from the in Madrid have modelled the effect of visitors over a number of years and say that tourists would increase the temperature, humidity and carbon-dioxide levels in the cave, creating conditions in which microbes would thrive.

In addition, visitors would bring with them organic matter in the form of skin flakes, clothing fibres and dust, which microbes can consume. Air turbulence created by moving people would spread bacterial and fungal spores to other, previously unaffected spaces.

Another Lascaux?

Although reopening the caves might boost the economy in the short term, says lead researcher Cesáreo Sáiz Jiménez, the damage would outweigh the benefit. “The paintings are a legacy from the past and their importance exceeds local culture.”

The researchers say they want to prevent the scale of damage that occurred at the Lascaux cave in France, where mismanagement led to successive waves of pathogens attacking wall paintings there. For example, pesticides intended to destroy microorganisms became a source of nutrients for them instead.

Sáiz Jiménez and his colleagues conclude that only isolation from the outside world can prevent the same kind of damage at Altamira.

Journal reference: , DOI: 10.1126/science.1206788