Engineers design soft and flexible 'skeletons' for muscle-powered robots

Our muscles are nature's perfect actuators -- devices that turn energy into motion. For their size, muscle fibers are more powerful and precise than most synthetic actuators. They can even heal from damage and grow stronger with exercise.

For these reasons, engineers are exploring ways to power robots with natural muscles. They've demonstrated a handful of "biohybrid" robots that use muscle-based actuators to power artificial skeletons that walk, swim, pump, and grip. But for every bot, there's a very different build, and no general blueprint for how to get the most out of muscles for any given robot design.

Now, MIT engineers have developed a spring-like device that could be used as a basic skeleton-like module for almost any muscle-bound bot. The new spring, or "flexure," is designed to get the most work out of any attached muscle tissues. Like a leg press that's fit with just the right amount of weight, the device maximizes the amount of movement that a muscle can naturally produce.

The researchers found that when they fit a ring of muscle tissue onto the device, much like a rubber band stretched around two posts, the muscle pulled on the spring, reliably and repeatedly, and stretched it five times more, compared with other previous device designs.

The team sees the flexure design as a new building block that can be combined with other flexures to build any configuration of artificial skeletons. Engineers can then fit the skeletons with muscle tissues to power their movements.

"These flexures are like a skeleton that people can now use to turn muscle actuation into multiple degrees of freedom of motion in a very predictable way," says Ritu Raman, the Brit and Alex d'Arbeloff Career Development Professor in Engineering Design at MIT. "We are giving roboticists a new set of rules to make powerful and precise muscle-powered robots that do interesting things."

Raman and her colleagues report the details of the new flexure design in a paper appearing in the journal Advanced Intelligent Systems. The study's MIT co-authors include Naomi Lynch '12, SM '23; undergraduate Tara Sheehan; graduate students Nicolas Castro, Laura Rosado, and Brandon Rios; and professor of mechanical engineering Martin Culpepper.

Muscle pull

When left alone in a petri dish in favorable conditions, muscle tissue will contract on its own but in directions that are not entirely predictable or of much use.

"If muscle is not attached to anything, it will move a lot, but with huge variability, where it's just flailing around in liquid," Raman says.

To get a muscle to work like a mechanical actuator, engineers typically attach a band of muscle tissue between two small, flexible posts. As the muscle band naturally contracts, it can bend the posts and pull them together, producing some movement that would ideally power part of a robotic skeleton. But in these designs, muscles have produced limited movement, mainly because the tissues are so variable in how they contact the posts. Depending on where the muscles are placed on the posts, and how much of the muscle surface is touching the post, the muscles may succeed in pulling the posts together but at other times may wobble around in uncontrollable ways.

Raman's group looked to design a skeleton that focuses and maximizes a muscle's contractions regardless of exactly where and how it is placed on a skeleton, to generate the most movement in a predictable, reliable way.

"The question is: How do we design a skeleton that most efficiently uses the force the muscle is generating?" Raman says.

The researchers first considered the multiple directions that a muscle can naturally move. They reasoned that if a muscle is to pull two posts together along a specific direction, the posts should be connected to a spring that only allows them to move in that direction when pulled.

"We need a device that is very soft and flexible in one direction, and very stiff in all other directions, so that when a muscle contracts, all that force gets efficiently converted into motion in one direction," Raman says.

Soft flex

As it turns out, Raman found many such devices in Professor Martin Culpepper's lab. Culpepper's group at MIT specializes in the design and fabrication of machine elements such as miniature actuators, bearings, and other mechanisms, that can be built into machines and systems to enable ultraprecise movement, measurement, and control, for a wide variety of applications. Among the group's precision machined elements are flexures -- spring-like devices, often made from parallel beams, that can flex and stretch with nanometer precision.

"Depending on how thin and far apart the beams are, you can change how stiff the spring appears to be," Raman says.

She and Culpepper teamed up to design a flexure specifically tailored with a configuration and stiffness to enable muscle tissue to naturally contract and maximally stretch the spring. The team designed the device's configuration and dimensions based on numerous calculations they carried out to relate a muscle's natural forces with a flexure's stiffness and degree of movement.

The flexure they ultimately designed is 1/100 the stiffness of muscle tissue itself. The device resembles a miniature, accordion-like structure, the corners of which are pinned to an underlying base by a small post, which sits near a neighboring post that is fit directly onto the base. Raman then wrapped a band of muscle around the two corner posts (the team molded the bands from live muscle fibers that they grew from mouse cells), and measured how close the posts were pulled together as the muscle band contracted.

The team found that the flexure's configuration enabled the muscle band to contract mostly along the direction between the two posts. This focused contraction allowed the muscle to pull the posts much closer together -- five times closer -- compared with previous muscle actuator designs.

"The flexure is a skeleton that we designed to be very soft and flexible in one direction, and very stiff in all other directions," Raman says. "When the muscle contracts, all the force is converted into movement in that direction. It's a huge magnification."

The team found they could use the device to precisely measure muscle performance and endurance. When they varied the frequency of muscle contractions (for instance, stimulating the bands to contract once versus four times per second), they observed that the muscles "grew tired" at higher frequencies, and didn't generate as much pull.

"Looking at how quickly our muscles get tired, and how we can exercise them to have high-endurance responses -- this is what we can uncover with this platform," Raman says.

The researchers are now adapting and combining flexures to build precise, articulated, and reliable robots, powered by natural muscles.

Read more at Science Daily

Vittrup Man crossed over from forager to farmer before being sacrificed in Denmark

Vittrup Man was born along the Scandinavian coast before moving to Denmark, where he was later sacrificed, according to a study published February 14, 2024 in the open-access journal PLOS ONE by Anders Fischer of the University of Gothenburg, Sweden and colleagues.

Vittrup Man is the nickname of a Stone Age skeleton recovered from a peat bog in Northwest Denmark, dating to between 3300-3100 BC. The fragmented nature of the remains, including a smashed skull, indicate that he was killed in a ritualistic sacrifice, a common practice in this region at this time.

After a DNA study found Vittrup Man's genetic signature to be distinct from contemporary, local skeletons, Fischer and colleagues were inspired to combine additional evidence to reconstruct the life history of this Stone Age individual at an unprecedented resolution.

Strontium, carbon and oxygen isotopes from Vittrup Man's tooth enamel indicate a childhood spent along the coast of the Scandinavian Peninsula.

Corroborating this, genetic analysis found a close relationship between Vittrup Man and Mesolithic people from Norway and Sweden.

Additional isotope and protein analysis of the teeth and bones indicate a shift in diet from coastal food (marine mammals and fish) in early life to farm food (including sheep or goat) in later life, a transition that happened in the later teen years.

These results suggest that Vittrup Man spent his early years in a northern foraging society before relocating to a farming society in Denmark.

It isn't clear why this individual moved, though the authors suggest he might have been a trader or captive who became integrated into local society.

Mysteries remain about Vittrup Man, but this detailed understanding of his geographic and dietary life history provides new insights into interactions between Mesolithic and Neolithic societies in Europe.

Read more at Science Daily

Scandinavia's first farmers slaughtered the hunter-gatherer population, study finds

Following the arrival of the first farmers in Scandinavia 5,900 years ago, the hunter-gatherer population was wiped out within a few generations, according to a new study from Lund University in Sweden, among others. The results, which are contrary to prevailing opinion, are based on DNA analysis of skeletons and teeth found in what is now Denmark.

The extensive study has been published as four separate articles in the journal Nature. An international research team, of which Lund University in Sweden is a member, has been able to draw new conclusions about the effects of migration on ancient populations by extracting DNA from skeletal parts and teeth of prehistoric people.

The study shows, among other things, that there have been two almost total population turnovers in Denmark over the past 7,300 years.

The first population change happened 5,900 years ago when a farmer population, with a different origin and appearance, drove out the gatherers, hunters and fishers who had previously populated Scandinavia.

Within a few generations, almost the entire hunter-gatherer population was wiped out.

"This transition has previously been presented as peaceful. However, our study indicates the opposite. In addition to violent death, it is likely that new pathogens from livestock finished off many gatherers," says Anne Birgitte Nielsen, geology researcher and head of the Radiocarbon Dating Laboratory at Lund University.

A thousand years later, about 4,850 years ago, another population change took place when people with genetic roots in Yamnaya -- a livestock herding people with origins in southern Russia -- came to Scandinavia and wiped out the previous farmer population.

Once again, this could have involved both violence and new pathogens.

These big-boned people pursued a semi-nomadic life on the steppes, tamed animals, kept domestic cattle and moved over large areas using horses and carts.

The people who settled in our climes were a mix between Yamnaya and Eastern European Neolithic people.

This genetic profile is dominant in today's Denmark, whereas the DNA profile of the first farmer population has been essentially erased.

"This time there was also a rapid population turnover, with virtually no descendants from the predecessors. We don't have as much DNA material from Sweden, but what there is points to a similar course of events. In other words, many Swedes are to a great extent also descendants of these semi-nomads," says Anne Birgitte Nielsen, who contributed quantitative pollen data which shows how the vegetation changed in connection with the population changes.

The results do not just overturn previous theories about amorous and peaceful meetings between groups of people.

The study also provides a deepened understanding of historical migration flows, and the interpretation of archaeological finds and changes in vegetation and land use found in palaeoecological data.

"Our results help to enhance our knowledge of our heredity and our understanding of the development of certain diseases. Something that in the long term could be beneficial, for example in medical research," concludes Anne Birgitte Nielsen.

Read more at Science Daily

Oldest bat skeletons ever found described from Wyoming fossils

Scientists have described a new species of bat based on the oldest bat skeletons ever recovered. The study on the extinct bat, which lived in Wyoming about 52 million years ago, supports the idea that bats diversified rapidly on multiple continents during this time. Led by researchers at the American Museum of Natural History and Naturalis Biodiversity Center in the Netherlands, the study is published today in the journal PLOS ONE.

There are more than 1,460 living species of bats found in nearly every part of the world, with the exception of the polar regions and a few remote islands. In the Green River Formation of Wyoming -- a remarkable fossil deposit from the early Eocene -- scientists have uncovered over 30 bat fossils in the last 60 years, but until now they were all thought represent the same two species.

"Eocene bats have been known from the Green River Formation since the 1960s. But interestingly, most specimens that have come out of that formation were identified as representing a single species, Icaronycteris index, up until about 20 years ago, when a second bat species belonging to another genus was discovered," said study co-author Nancy Simmons, curator-in-charge of the Museum's Department of Mammalogy, who helped describe that second species in 2008. "I always suspected that there must be even more species there."

In recent years, scientists from the Naturalis Biodiversity Center started looking closely at Icaronycteris index by collecting measurements and other data from museum specimens.

"Paleontologists have collected so many bats that have been identified as Icaronycteris index, and we wondered if there were actually multiple species among these specimens," said Tim Rietbergen, an evolutionary biologist at Naturalis. "Then we learned about a new skeleton that diverted our attention."

The exceptionally well-preserved skeleton was collected by a private collector in 2017 and purchased by the Museum. When researchers compared the fossil to Rietbergen's expansive dataset, it clearly stood out as a new species. A second fossil skeleton discovered in the same quarry in 1994 and in the collections of the Royal Ontario Museum was also identified as this new species. The researchers gave these fossils the species name Icaronycteris gunnelli in honor of Gregg Gunnell, a Duke University paleontologist who died in 2017 and made extensive contributions to the understanding of fossil bats and evolution.

Although there are fossil bat teeth from Asia that are slightly older, the two I. gunnelli fossils represent the oldest bat skeletons ever found.

"The Fossil Lake deposits of the Green River Formation are simply amazing because the conditions that created the paper-thin limestone layers also preserved nearly everything that settled to the lake's bottom," said Arvid Aase, park manager and curator at the Fossil Butte National Monument, in Wyoming. "One of these bat specimens was found lower in the section than all other bats, making this species older than any of the other bat species recovered from this deposit."

While the I. gunnelli skeletons are the oldest bat fossils from this site, they are not the most primitive, supporting the idea that Green River bats evolved separately from other Eocene bats around the world.

Read more at Science Daily

One of Swedish warship Vasa's crew was a woman

When the human remains found on board the warship Vasa were investigated, it was determined that the skeleton designated G was a man. New research now shows that the skeleton is actually from a woman.

About thirty people died when Vasa sank on its maiden voyage in 1628. We cannot know who most of them were, only one person is named in the written sources. When the ship was raised in 1961 it was the scene of a comprehensive archaeological excavation, in which numerous human bones were found on board and examined.

“Through osteological analysis it has been possible to discover a great deal about these people, such as their age, height and medical history. Osteologists recently suspected that G could be female, on the basis of the pelvis. DNA analysis can reveal even more”, says Dr Fred Hocker, director of research at the Vasa Museum, in Stockholm, Sweden.

Since 2004 the Vasa Museum has collaborated with the Department of Immunology, Genetics and Pathology at Uppsala University in Sweden to investigate all of the remains from Vasa and find out as much as possible about each individual. Initially the project focused on confirming if certain bones belonged to a specific person. Marie Allen, professor of forensic genetics, has led the work.

“For us, it is both interesting and challenging to study the skeletons from Vasa. It is very difficult to extract DNA from bone which has been on the bottom of the sea for 333 years, but not impossible”, says Marie Allen. She continues:

“Already some years ago we had indications that skeleton G was not a man but a woman. Simply put, we found no Y-chromosomes in G’s genetic material. But we could not be certain and wanted to confirm the result”.

The result has now been confirmed thanks to an interlaboratory study with Dr Kimberly Andreaggi of the Armed Forces Medical Examiner System’sArmed Forces DNA Identification Laboratory (AFMES-AFDIL) in Delaware, USA. The AFMES-AFDIL is the American Department of Defense’s laboratory, specializing in human remains DNA testing from deceased military personnel. They have established a new testing method for the analysis of many different genetic variants.

“We took new samples from bones for which we had specific questions. AFMES-AFDIL has now analysed the samples, and we have been able to confirm that G was a woman, thanks to the new test”, says Marie Allen.

For Marie Allen and Kimberly Andreaggi, the analysis of the Vasa skeletons is a way to develop their forensic methods, which can then be used to analyse DNA in criminal investigations or to identify fallen soldiers.

For the Vasa Museum the results of the DNA analysis are an important puzzle piece in the museum’s research into the people on the ship. Dr. Anna Maria Forssberg, historian and researcher at the museum, explains:

“We want to come as close to these people as we can. We have known that there were women on board Vasa when it sank, and now we have received confirmation that they are among the remains. I am currently researching the wives of seamen, so for me this is especially exciting, since they are often forgotten even though they played an important role for the navy“.

More results are expected shortly from the new samples. Marie Allen and Kimberly Andreaggi will be able to say something about how individuals looked, what colour their hair and eyes had, and possibly where their families came from.

“Today we can extract much more information from historic DNA than we could earlier and methods are being continuously refined. We can say if a person was predisposed to certain illnesses, or even very small details, such as if they had freckles and wet or dry ear wax”, says Marie Allen.

Read more at Science Daily

The world's first horse riders

The researchers discovered evidence of horse riding by studying the remains of human skeletons found in burial mounds called kurgans, which were between 4500-5000 years old. The earthen burial mounds belonged to the Yamnaya culture. The Yamnayans had migrated from the Pontic-Caspian steppes to find greener pastures in today´s countries of Romania and Bulgaria up to Hungary and Serbia.

Yamnayans were mobile cattle and sheep herders, now believed to be on horseback.

"Horseback-riding seems to have evolved not long after the presumed domestication of horses in the western Eurasian steppes during the fourth millennium BCE. It was already rather common in members of the Yamnaya culture between 3000 and 2500 BCE," says Volker Heyd, Professor of Archaeology at the University of Helsinki and a member of the international team, which made the discovery.

These regions west of the Black Sea constitute a contact zone where mobile groups of herdsmen from the Yamnaya culture first encountered the long-established farmer communities of Late Neolithic and Chalcolithic traditions. For decades, the Early Bronze Age expansion of steppe people into southeastern Europe was explained as a violent invasion.

With the advent of ancient DNA research, the differences between these migrants from the east and members of local societies became even more pronounced.

"Our research is now beginning to provide a more nuanced picture of their interactions. For example, findings of physical violence as were expected are practically non-existent in the skeletal record so far. We also start understanding the complex exchange processes in material culture and burial customs between newcomers and locals in the 200 years after their first contact," explains Bianca Preda-Bălănică, another team member from the University of Helsinki.

Horse riding is a pivotal moment in human history

The use of animals for transport, in particular the horse, marked a turning point in human history. The considerable gain in mobility and distance had profound effects on land use, trade, and warfare. Current research has mostly focused on the horses themselves. However, horse-riding is an interaction of two components -- the mount and its rider -- and human remains are available in larger numbers and more complete condition than early horse remains. Since horseback riding is possible without specialized equipment, the absence of archaeological finds with regard to earliest horsemanship does not come unexpected.

Traces of horsemanship can be found in the skeletons

"We studied over 217 skeletons from 39 sites of which about 150 found in the burial mounds belong to the Yamnayans. Diagnosing activity patterns in human skeletons is not unambiguously. There are no singular traits that indicate a certain occupation or behavior. Only in their combination, as a syndrome, symptoms provide reliable insights to understand habitual activities of the past.," explains Martin Trautmann, Bioanthropologist in Helsinki and the lead author of the study.

The international team decided to use a set of six diagnostic criteria established as indicators of riding activity (the so-called "horsemanship syndrome"):

1. Muscle attachment sites on pelvis and thigh bone (femur);

2. Changes in the normally round shape of the hip sockets;

3. Imprint marks caused by pressure of the acetabular rim on the neck of the femur;

4. The diameter and form of the femur shaft;

5. Vertebral degeneration caused by repeated vertical impact;

6. Traumata that typically can be caused by falls, kicks or bites from horses.

To increase the diagnostic reliability, the team also used a stricter filtering method and developed a scoring system that takes into account the diagnostic value, distinctiveness and reliability of each symptom. Altogether, out of the 156 adult individuals of the total sample at least 24 (15.4%) can be classified as 'possible riders', while five Yamnaya and two later as well as two possibly earlier individuals qualify as 'highly probable riders'. "The rather high prevalence of these traits in the skeleton record, especially with respect to the overall limited completeness, show that these people were horse riding regularly," Trautmann states.

If the primary use of horseback riding was as a convenience in a mobile pastoral lifestyle, in allowing a more effective herding of cattle, as means of swift and far-ranging raids or just as symbol of status needs further research.

Could it all have happened even earlier?

"We have one intriguing burial in the series" remarks David Anthony, emeritus Professor of Hartwick College USA and also senior co-author in the study.

"A grave dated about 4300 BCE at Csongrad-Kettöshalom in Hungary, long suspected from its pose and artifacts to have been an immigrant from the steppes, surprisingly showed four of the six riding pathologies, possibly indicating riding a millennium earlier than Yamnaya. An isolated case cannot support a firm conclusion, but in Neolithic cemeteries of this era in the steppes, horse remains were occasionally placed in human graves with those of cattle and sheep, and stone maces were carved into the shape of horse heads. Clearly, we need to apply this method to even older collections."

Read more at Science Daily

Fossil overturns more than a century of knowledge about the origin of modern birds

Fossilised fragments of a skeleton, hidden within a rock the size of a grapefruit, have helped upend one of the longest-standing assumptions about the origins of modern birds.

Researchers from the University of Cambridge and the Natuurhistorisch Museum Maastricht found that one of the key skull features that characterises 99% of modern birds -- a mobile beak -- evolved before the mass extinction event that killed all large dinosaurs, 66 million years ago.

This finding also suggests that the skulls of ostriches, emus and their relatives evolved 'backwards', reverting to a more primitive condition after modern birds arose.

Using CT scanning techniques, the Cambridge team identified bones from the palate, or the roof of the mouth, of a new species of large ancient bird, which they named Janavis finalidens. It lived at the very end of the Age of Dinosaurs and was one of the last toothed birds to ever live. The arrangement of its palate bones shows that this 'dino-bird' had a mobile, dexterous beak, almost indistinguishable from that of most modern birds.

For more than a century, it had been assumed that the mechanism enabling a mobile beak evolved after the extinction of the dinosaurs. However, the new discovery, reported in the journal Nature, suggests that our understanding of how the modern bird skull came to be needs to be re-evaluated.

Each of the roughly 11,000 species of birds on Earth today is classified into one of two over-arching groups, based on the arrangement of their palate bones. Ostriches, emus and their relatives are classified into the palaeognath, or 'ancient jaw' group, meaning that, like humans, their palate bones are fused together into a solid mass.

All other groups of birds are classified into the neognath, or 'modern jaw' group, meaning that their palate bones are connected by a mobile joint. This makes their beaks much more dexterous, helpful for nest-building, grooming, food-gathering, and defence.

The two groups were originally classified by Thomas Huxley, the British biologist known as 'Darwin's Bulldog' for his vocal support of Charles Darwin's theory of evolution. In 1867, he divided all living birds into either the 'ancient' or 'modern' jaw groups. Huxley's assumption was that the 'ancient' jaw configuration was the original condition for modern birds, with the 'modern' jaw arising later.

"This assumption has been taken as a given ever since," said Dr Daniel Field from Cambridge's Department of Earth Sciences, the paper's senior author. "The main reason this assumption has lasted is that we haven't had any well-preserved fossil bird palates from the period when modern birds originated."

The fossil, Janavis, was found in a limestone quarry near the Belgian-Dutch border in the 1990s and was first studied in 2002. It dates from 66.7 million years ago, during the last days of the dinosaurs. Since the fossil is encased in rock, scientists at the time could only base their descriptions on what they could see from the outside. They described the bits of bone sticking out from the rock as fragments of skull and shoulder bones, and put the unremarkable-looking fossil back in storage.

Nearly 20 years later, the fossil was loaned to Field's group in Cambridge, and Dr Juan Benito, then a PhD student, started giving it another look.

"Since this fossil was first described, we've started using CT scanning on fossils, which enables us to see through the rock and view the entire fossil," said Benito, now a postdoctoral researcher at Cambridge, and the paper's lead author. "We had high hopes for this fossil -- it was originally said to have skull material, which isn't often preserved, but we couldn't see anything that looked like it came from a skull in our CT scans, so we gave up and put the fossil aside."

During the early days of Covid-19 lockdown, Benito took the fossil out again. "The earlier descriptions of the fossil just didn't make sense -- there was a bone I was really puzzled by. I couldn't see how what was first described as a shoulder bone could actually be a shoulder bone," he said.

"It was my first in-person interaction in months: Juan and I had a socially distanced outdoor meeting, and he passed the mystery fossil bone to me," said Field, who is also the Curator of Ornithology at Cambridge's Museum of Zoology. "I could see it wasn't a shoulder bone, but there was something familiar about it."

"Then we realised we'd seen a similar bone before, in a turkey skull," said Benito. "And because of the research we do at Cambridge, we happen to have things like turkey skulls in our lab, so we brought one out and the two bones were almost identical."

The realisation that the bone was a skull bone, and not a shoulder bone, led the researchers to conclude that the unfused 'modern jaw' condition, which turkeys share, evolved before the 'ancient jaw' condition of ostriches and their relatives. For an unknown reason, the fused palates of ostriches and kin must have evolved at some point after modern birds were already established.

Two of the key characteristics we use to differentiate modern birds from their dinosaur ancestors are a toothless beak and a mobile upper jaw. While Janavis finalidens still had teeth, making it a pre-modern bird, its jaw structure is that of the modern, mobile kind.

"Using geometric analyses, we were able to show that the shape of the fossil palate bone was extremely similar to those of living chickens and ducks" said Pei-Chen Kuo, a co-author of the study. Added co-author Klara Widrig: "Surprisingly, the bird palate bones that are the least similar to that of Janavis are from ostriches and their kin." Both Kuo and Widrig are PhD students in Field's lab at Cambridge.

"Evolution doesn't happen in a straight line," said Field. "This fossil shows that the mobile beak -- a condition we had always thought post-dated the origin of modern birds, actually evolved before modern birds existed. We've been completely backwards in our assumptions of how the modern bird skull evolved for well over a century."

The researchers say that while this discovery does not mean that the entire bird family tree needs to be redrawn, it does rewrite our understanding of a key evolutionary feature of modern birds.

Read more at Science Daily

500 million year-old fossils reveal answer to evolutionary riddle

An exceptionally well-preserved collection of fossils discovered in eastern Yunnan Province, China, has enabled scientists to solve a centuries-old riddle in the evolution of life on earth, revealing what the first animals to make skeletons looked like. The results have been published today in Proceedings of the Royal Society B.

The first animals to build hard and robust skeletons appear suddenly in the fossil record in a geological blink of an eye around 550-520 million years ago during an event called the Cambrian Explosion. Many of these early fossils are simple hollow tubes ranging from a few millimetres to many centimetres in length. However, what sort of animals made these skeletons was almost completely unknown, because they lack preservation of the soft parts needed to identify them as belonging to major groups of animals that are still alive today.

The new collection of 514 million year old fossils includes four specimens of Gangtoucunia aspera with soft tissues still intact, including the gut and mouthparts. These reveal that this species had a mouth fringed with a ring of smooth, unbranched tentacles about 5 mm long. It's likely that these were used to sting and capture prey, such as small arthropods. The fossils also show that Gangtoucunia had a blind-ended gut (open only at one end), partitioned into internal cavities, that filled the length of the tube.

These are features found today only in modern jellyfish, anemones and their close relatives (known as cnidarians), organisms whose soft parts are extremely rare in the fossil record. The study shows that these simple animals was among the first to build the hard skeletons that make up much of the known fossil record.

According to the researchers, Gangtoucunia would have looked similar to modern scyphozoan jellyfish polyps, with a hard tubular structure anchored to the underlying substrate. The tentacle mouth would have extended outside the tube, but could have been retracted inside the tube to avoid predators. Unlike living jellyfish polyps however, the tube of Gangtoucunia was made of calcium phosphate, a hard mineral that makes up our own teeth and bones. Use of this material to build skeletons has become more rare among animals over time.

Corresponding author Dr Luke Parry, Department of Earth Sciences, University of Oxford, said: 'This really is a one-in-million discovery. These mysterious tubes are often found in groups of hundreds of individuals, but until now they have been regarded as 'problematic' fossils, because we had no way of classifying them. Thanks to these extraordinary new specimens, a key piece of the evolutionary puzzle has been put firmly in place.'

The new specimens clearly demonstrate that Gangtoucunia was not related to annelid worms (earthworms, polychaetes and their relatives) as had been previously suggested for similar fossils. It is now clear that Gangtoucunia's body had a smooth exterior and a gut partitioned longitudinally, whereas annelids have segmented bodies with transverse partitioning of the body.

The fossil was found at a site in the Gaoloufang section in Kunming, eastern Yunnan Province, China. Here, anaerobic (oxygen-poor) conditions limit the presence of bacteria that normally degrade soft tissues in fossils.

PhD student Guangxu Zhang, who collected and discovered the specimens, said: 'The first time I discovered the pink soft tissue on top of a Gangtoucunia tube, I was surprised and confused about what they were. In the following month, I found three more specimens with soft tissue preservation, which was very exciting and made me rethink the affinity of Gangtoucunia. The soft tissue of Gangtoucunia, particularly the tentacles, reveals that it is certainly not a priapulid-like worm as previous studies suggested, but more like a coral, and then I realised that it is a cnidarian.'

Although the fossil clearly shows that Gangtoucunia was a primitive jellyfish, this doesn't rule out the possibility that other early tube-fossil species looked very different. From Cambrian rocks in Yunnan province, the research team have previously found well-preserved tube fossils that could be identified as priapulids (marine worms), lobopodians (worms with paired legs, closely related to arthropods today) and annelids.

Read more at Science Daily

Ankle exoskeleton enables faster walking

Being unable to walk quickly can be frustrating and problematic, but it is a common issue, especially as people age. Noting the pervasiveness of slower-than-desired walking, engineers at Stanford University have tested how well a prototype exoskeleton system they have developed -- which attaches around the shin and into a running shoe -- increased the self-selected walking speed of people in an experimental setting.

The exoskeleton is externally powered by motors and controlled by an algorithm. When the researchers optimized it for speed, participants walked, on average, 42 percent faster than when they were wearing normal shoes and no exoskeleton. The results of this study were published April 20 in IEEE Transactions on Neural Systems and Rehabilitation Engineering.

"We were hoping that we could increase walking speed with exoskeleton assistance, but we were really surprised to find such a large improvement," said Steve Collins, associate professor of mechanical engineering at Stanford and senior author of the paper. "Forty percent is huge."

For this initial set of experiments, the participants were young, healthy adults. Given their impressive results, the researchers plan to run future tests with older adults and to look at other ways the exoskeleton design can be improved. They also hope to eventually create an exoskeleton that can work outside the lab, though that goal is still a ways off.

"My research mission is to understand the science of biomechanics and motor control behind human locomotion and apply that to enhance the physical performance of humans in daily life," said Seungmoon Song, a postdoctoral fellow in mechanical engineering and lead author of the paper. "I think exoskeletons are very promising tools that could achieve that enhancement in physical quality of life."

Walking in the loop

The ankle exoskeleton system tested in this research is an experimental emulator that serves as a testbed for trying out different designs. It has a frame that fastens around the upper shin and into an integrated running shoe that the participant wears. It is attached to large motors that sit beside the walking surface and pull a tether that runs up the length of the back of the exoskeleton. Controlled by an algorithm, the tether tugs the wearer's heel upward, helping them point their toe down as they push off the ground.

For this study, the researchers had 10 participants walk with five different modes of operation. They walked in normal shoes without the exoskeleton, with the exoskeleton turned off and with the exoskeleton turned on with three different modes: optimized for speed, optimized for energy use, and a placebo mode adjusted to make them walk more slowly. In all of the tests, participants walked on a treadmill that adapts to their speed.

The mode that was optimized for speed -- which resulted in the 42 percent increase in walking pace -- was created through a human-in-the-loop process. An algorithm repeatedly adjusted the exoskeleton settings while the user walked, with the goal of improving the user's speed with each adjustment. Finding the speed-optimized mode of operation took about 150 rounds of adjustment and two hours per person.

In addition to greatly increasing walking speed, the speed-optimized mode also reduced energy use, by about 2 percent per meter traveled. However, that result varied widely from person to person, which is somewhat expected, given that it was not an intentional feature of that exoskeleton mode.

"The study was designed to specifically answer the scientific question about increasing walking speed," Song said. "We didn't care too much about the other performance measures, like comfort or energy. However, seven out of 10 participants not only walked faster but consumed less energy, which really shows how much potential exoskeletons have for helping people in an efficient way."

The settings that were optimized specifically for energy use were borrowed from a previous experiment. In the current study, this mode decreased energy use more than the speed-optimized settings but did not increase speed as much. As intended, the placebo mode both slowed down participants and boosted their energy use.

Better, faster, stronger

Now that the researchers have attained such significant speed assistance, they plan to focus future versions of the ankle exoskeleton emulator on reducing energy use consistently across users, while also being more comfortable.

In considering older adults specifically, Collins and his lab wonder whether future designs could reduce pain caused by weight on joints or improve balance. They plan to conduct similar walking tests with older adults and hope those provide encouraging results as well.

Read more at Science Daily

Corals carefully organize proteins to form rock-hard skeletons

Charles Darwin, the British naturalist who championed the theory of evolution, noted that corals form far-reaching structures, largely made of limestone, that surround tropical islands. He didn't know how they performed this feat.

Now, Rutgers scientists have shown that coral structures consist of a biomineral containing a highly organized organic mix of proteins that resembles what is in our bones. Their study, published in the Journal of the Royal Society Interface, shows for the first time that several proteins are organized spatially -- a process that's critical to forming a rock-hard coral skeleton.

"Our research revealed an intricate network of skeletal proteins that interact spatially, which likely applies to all stony corals," said Manjula P. Mummadisetti, who led the research while she was a postdoctoral associate in the Rutgers Environmental Biophysics and Molecular Ecology Laboratory led by senior author Paul G. Falkowski. She is now a senior scientist at AVMBioMed in Pottstown, Pennsylvania. "It's important to understand the mechanisms of coral biomineralization and how these invaluable animals persist during the era of anthropogenic climate change."

"Our findings suggest that corals will withstand climate change caused by human activities, based on the precision, robustness and resilience of their impressive process for forming rock-hard skeletons," said Falkowski, a Distinguished Professor in the School of Arts and Sciences and School of Environmental and Biological Sciences at Rutgers University-New Brunswick.

Coral reefs protect shorelines threatened by erosion and storms, and provide fish habitat, nursery and spawning grounds. Indeed, coral reefs provide food for about a half-billion people, who also depend on them to make a living. However, warming ocean waters from climate change put corals at risk from deadly bleaching and disease. More acidic ocean waters, sea-level rise, unsustainable fishing, vessels that damage reefs, invasive species, marine debris and tropical cyclones pose additional threats, according to the National Oceanic and Atmospheric Administration.

Rutgers scientists studied the spatial interactions of the proteins embedded within the skeleton of Stylophora pistillata, a common stony coral in the Indo-Pacific. Stony corals have evolved over more than 400 million years, forming enormous reefs in shallow subtropical and tropical seas. They've been called the "rainforests of the sea."

Predicting the survival of corals based on how they adapted to global climate change over millions of years requires understanding, among other things, how they build reefs by secreting calcium carbonate. That process is called biomineralization.

The scientists showed that several proteins work together to create optimal conditions for biomineralization. These proteins are not located randomly but are well-organized spatially, which the scientists detailed for the first time. The scientists revealed the spatial patterns as new mineral is formed between the living tissue of the animal and its base or an older skeleton.

Read more at Science Daily

Unlocking the mystery behind skeletal aging

 Researchers from the UCLA School of Dentistry have identified the role a critical enzyme plays in skeletal aging and bone loss, putting them one step closer to understanding the complex biological mechanisms that lead to osteoporosis, the bone disease that afflicts some 200 million people worldwide.

The findings from their study in mice, published online in the journal Cell Stem Cell, could hold an important key to developing more effective treatments for osteoporosis and improving the lives of an aging population, they say.

Cells in the bone marrow known as mesenchymal stem cells serve as the building blocks of the body's skeletal tissues, but whether these stem cells ultimately develop into bone or fat tissues is controlled in part by what are known as epigenetic factors -- molecules that regulate genes, silencing some and activating others.

The UCLA researchers, led by distinguished professor Dr. Cun-Yu Wang, chair of oral biology at the dentistry school, demonstrated that when the epigenetic factor KDM4B is absent from mesenchymal stem cells, these cells are far more likely to differentiate into fat cells than bone cells, resulting in an unhealthy imbalance that exacerbates skeletal aging and leads to brittle bones and fractures over time.

"We know that bone loss comes with age, but the mechanisms behind extreme cases such as osteoporosis have, up until recently, been very vague," said Dr Wang, the study's corresponding author and the Dr. No-Hee Park Professor of Dentistry at UCLA. "In this study, we built on more than seven years of research managed by my postdoctoral scholar and lead author Dr. Peng Deng in the hope that we can eventually prevent skeletal aging and osteoporosis."

While scientists have long understood the cellular pathway involved in bone tissue formation, the role of epigenetic factors has been murkier. Previous research by Wang, Deng and others had identified that the enzyme KDM4B plays an important epigenetic role in bone formation, but they were unsure of how its absence might affect the processes of bone formation and bone loss.

To test this, the research team created a mouse model in which KDM4B was absent or removed in several different scenarios. They found that the removal of the enzyme pushed mesenchymal stem cells to create more fat instead of bone tissue, leading to bone loss over time, which mimics skeletal aging.

In one important scenario, the scientists examined stem cell senescence, or deterioration and exhaustion -- the natural process by which mesenchymal stem cells stop rejuvenating or creating more of themselves over time. The team unexpectedly found that senescence, which leads to natural skeletal aging, was characterized by a loss of KDM4B.

In addition to age, other environmental factors are thought to reduce bone quality and exacerbate bone loss, including a high-fat diet. The team demonstrated that a loss of KDM4B significantly promoted bone loss and the accumulation of marrow fat in mice placed on a high-fat diet.

Finally, the team showed that parathyroid hormone, an anabolic drug approved by the U.S. Food and Drug Administration for the treatment of aging-related bone loss, helps to maintain the pool of mesenchymal stem cells in aging mice in a KDM4B-dependent manner.

The results not only confirm the critical role KDM4B plays in mesenchymal stem cell fate decision, skeletal aging and osteoporosis, but they show that the loss of KDM4B exacerbates bone loss under a number of conditions and, surprisingly, that KDM4B controls the ability of mesenchymal stem cells to self-renew. This study is the first in vivo research to demonstrate that the loss of an epigenetic factor promotes adult stem cell deterioration and exhaustion in skeletal aging.

The findings, the researchers say, hold promise for the eventual development of strategies to reverse bone-fat imbalance, as well as for new prevention and treatment methods that address skeletal aging and osteoporosis by rejuvenating adult stem cells.

"The work of Dr. Wang, his lab members and collaborators provides new molecular insight into the changes associated with skeletal aging," said Dr. Paul Krebsbach, dean of the UCLA School of Dentistry. "These findings are an important step towards what may lead to more effective treatment for the millions of people who suffer from bone loss and osteoporosis."

Read more at Science Daily

2,500-Year-Old Skeleton Found Wrapped in Marijuana

Archaeologists in northwestern China have unearthed a 2,500-year-old skeleton wrapped in a "shroud" made up of well-preserved marijuana.

Found during an investigation of the Jiayi Cemetery in Turpan, which houses 240 ancient tombs, the burial contained "an extraordinary cache" of 13 Cannabis plants.

The three-foot long, locally produced plants, were arranged across the chest of a man who died at around age 35.

"The Cannabis plants were placed above the body trimly, in a way that suggests ritual-medicinal purposes," Hongen Jiang of the Department of Archaeology and Anthropology at the University of Chinese Academy of Sciences in Beijing, told Discovery News.

The man was laid down on a wooden bed with a reed pillow under the head, while 13 nearly whole female Cannabis plants were deposited diagonally across his body, with the roots and lower parts of the plants grouped together and placed below the pelvis.

"The stems and foliage were arranged in a parallel alignment extending upwards to just under the chin and along the left side of the face," Jiang and colleagues wrote in the journal Economic Botany.

Radiocarbon dating of the tomb's contents, including the cannabis plants, indicates the burial occurred sometime between 2,400 and 2,800 years ago.

While all of the plants had roots attached, most of the flowering heads had been cut off. The few flowers that remained were nearly ripe and contained some immature fruit, suggesting the plants were collected—and that the man was buried -- in late summer, around the end of August or early September.

The plants offer rare insight into ancient cultivation practices.

"Due to the extremely dry climate, the stems and foliage retained their characteristic natural shape although they had turned yellowish brown," the researchers said.

They noted this is the first case of cannabis plants used a as a covering for a human body.

Examining the way the plants were lying on the man's body, basically pressed flat, the researchers concluded they had been fresh and harvested just before the funeral.

"Therefore, the plants were most likely growing locally," they said.

Jiang and colleagues suspect the plants were just harvested for their psychoactive resin. The Cannabis plants were all females with nearly ripe seed, and the flower heads contained the psychoactive resin of Cannabis.

Read more at Discovery News

Bacteria Behind London's Great Plague ID'd

A skull is uncovered at the Bedlam burial ground where it is believed over 20,000 Londoners were buried between 1569 and 1738.

Using DNA testing, scientists have confirmed the identity of the bacteria that caused London's Great Plague in the 17th century, reports the BBC.

From 1665 - 1666 the bubonic plague killed 100,000 people in London, almost a quarter of the city's entire population. The disease spread rapidly and burial pits were sometimes created to accommodate the overwhelming number of bodies.

Last year, archaeologists in London believe they came upon one of these pits as excavations were underway at a former burial ground at Liverpool Street for a new rail link across the city, reported CNN. The bodies looked to be buried on the same day as others in the nearby Bedlam cemetery with headstones reading 1665, further leading scientists to believe those in the burial pit were killed by the plague.

During the course of this year-long excavation, 3,500 skeletons have been uncovered.

The osteology department at the Museum of London Archaeology, where all the finds from the Liverpool Street excavation were examined, searched for Yersinia pestis in the skeletons, a bacterium known to cause plague. Teeth were removed from the other remains and sent to the Max Planck Institute for the Science of Human History in Germany for further testing.

Molecular palaeopathologist Kirsten Bos found positive results for Yersinia pestis in the teeth of five out of 20 skeletons she examined, confirming this is the bacteria that caused the bubonic plague.

"We could clearly find preserved DNA signatures in the DNA extract we made from the pulp chamber and from that we were able to determine that Yersinia pestis was circulating in that individual at the time of death," she told the BBC.

Read more at Discovery News

Oldest Case of Leukemia Found on 7,000-Year-Old Skeleton

German researchers have discovered what might be the earliest case of leukemia in a 7,000-year-old skeleton, they announced at the first European conference on evolutionary medicine.

Belonging to a female individual who died at 30-40 years, the skeleton was excavated in 1982 among other 72 burials at an early Neolithic site near Stuttgart-Mühlhausen in south western Germany.

Beside the individual stood a round-bottomed jar. The site was linked with the Linear Pottery culture, an early farming culture which flourished in western and central Europe between 5500–4800 BC and produced pottery with distinctive linear decorations.

“So far only a severe case of dental caries with alveolar inflammation was reported for this individual,” team leader Heike Scherf, from the Senckenberg Center for Human Evolution and Paleoenvironment at the University of Tübingen in Germany, said.

Using high resolution CT scans, Scherf and colleagues found a pattern of deep loss of spongy bone in both the bone tissue of the humerus (the long bone that runs from the shoulder to the elbow) and the sternum, or breastbone.

According to the researchers, the resorption of central spongy bone is significantly higher compared to specimens of the same age group from the same site and to recent human samples of the adult age class.

“Our results strongly suggests leukemia in its initial stages, affecting the hematopoietic stem cells in bone marrow,” Scherf said.

The locally restricted destruction of the sternum and humerus’s bone tissue ruled out other diseases such as osteoporosis, hyperparathyroidism and bone tumor.

“A virus associated with a special type of leukemia (T-cell leukemia) was previously found in Andean mummies. But this case is probably the earliest known appearance of leukemia in an archeological case,” Scherf told Discovery News.

The researchers admitted it’s impossible to make any more detailed assumptions, such as establishing the type of leukemia that affected the Neolithic woman.

Read more at Discovery News