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Previously, researchers have suggested some strategies

That typically happens between a 2D sheet of electronics and a surface of the tissue

our work suggests a new approach—to build and grow the biology up with the electronics synergistically and in a 3D interwoven format

Last year, a research effort

resulted in the development of a "tattoo" made up of a biological sensor and antenna that can be affixed to the surface of a tooth

This project, however, is the team's first effort to create a fully functional organ: one that not only replicates a human ability, but extends it using embedded electronics

Creating organs using 3D printers is a recent advance; several groups have reported using the technology for this purpose in the past few months

this is the first time that researchers have demonstrated that 3D printing is a convenient strategy to interweave tissue with electronics

Ear reconstruction "remains one of the most difficult problems in the field of plastic and reconstructive surgery

the team turned to a manufacturing approach called 3D printing

The finished ear consists of a coiled antenna inside a cartilage structure

Two wires lead from the base of the ear and wind around a helical "cochlea" – the part of the ear that senses sound – which can connect to electrodes

further work and extensive testing would need to be done before the technology could be used on a patient

the ear in principle could be used to restore or enhance human hearing.

electrical signals produced by the ear could be connected to a patient's nerve endings, similar to a hearing aid

The current system receives radio waves, but he said the research team plans to incorporate other materials, such as pressure-sensitive electronic sensors, to enable the ear to register acoustic sounds

researchers used an ordinary 3D printer to combine a matrix of hydrogel and calf cells with silver nanoparticles that form an antenna. The calf cells later develop into cartilage

Dinosaur tracks are far more common

Stanford may have discovered a footprint of an adult ankylosaur in an unexpected place.

the print sits on the property of a NASA‘s Goddard Space Flight Center in Greenbelt, Maryland

Stanford stumbled across the lone track earlier this summer and recently led NASA scientists out to the site to show them the fossil depression

the track has started to erode, and may have been damaged by a lawnmower, the roughly 112-million-year-old track still shows four toe imprints

member of the heavily-armored ankylosaur subgroup that lacked tail clubs but often sported prominent spikes along their sides

Officials

are already moving to protect the fossil, and they plan to bring in paleontologists to look for other dinosaur tracks

it seems that there is more than just a lone track at the spaceflight facility. When Stanford took the NASA scientists out to the site, he and other researchers found several more possible dinosaur tracks. The high-tech NASA facility may have been founded on a Cretaceous dinosaur stomping ground.

about 65 to 67 million years ago

The skull

also showed signs of trauma

from the size and shape of the marks on the bone

paleontologist at the Palm Beach Museum of Natural History

speculate the creature was attacked by a T. rex

, though still unproven, that both the skin wound and the skull injury were sustained during the same attack,

. The wound "was large enough to have been a claw or a tooth,"

also compared the dinosaur wound to healed wounds on modern reptiles, including iguanas, and found the scar patterns to be nearly identical.

Phil Bell, a paleontologist with the Pipestone Creek Dinosaur Initiative in Canada

not convinced, however, that it was caused by a predator attack

The size of the scar is relatively small

, and would also be consistent with the skin being pierced in some other accident such as a fall.

certainly the marks that you see on the skull, those are [more consistent] with Tyrannosaur-bitten bones,"

Prior to the discovery, scientists knew of one other case of a dinosaur wound.

But in that instance, it was an unhealed wound that scientists think was inflicted by scavengers after the creature was already dead

It's very likely that this particular

wasn't the only dinosaur to sport scars, whether from battle wounds or accidents

Just how Edmontosaurus survived a T. rex attack is still unclear

. "Escape from a T. rex is something that we wouldn't think would happen,"

Duckbill dinosaurs

were not without defenses.

, for example, grew up to 30 feet (9 meters) in length, and could swipe its hefty tail or kick its legs to fell predators.

Furthermore, they were fast

had very powerful [running] muscles, which would have made them difficult to catch once they'd taken flight,"

Duckbills were also herd animals, so maybe this one escaped with help from neighbors

Figuring out the details of the story is part of what makes paleontology exciting

Imagine going to the doctor for your aching knees

what if your doctor could actually listen to your body, monitoring the way your knees sound as they bend and flex

an instrument called a Surface Forces Apparatus (SFA), a device that measures the adhesion and friction forces between surfaces—in this case cartilage, the pad of tissue that covers the ends of bones at a joint.

degeneration of cartilage is the most common cause of osteoarthritis: The pads wear away, leaving bone grinding against bone

researchers found is that it isn't just any kind of friction that leads to the irreversible wear and tear on the material

currently believed that a high-friction force, or 'coefficient of friction,' is the primary factor in surface wear and damage

found is that this is not the case

The critical feature is not a high-friction force, but what is known as "stick-slip" friction, or, sometimes, "stiction."

Both are characterized by surfaces that initially stick together, and then accelerate away quickly once the static friction force is overcome

With stick-slip friction, the surfaces eventually pull slightly apart and slide across each other, stick again, and pull apart, causing jerky movements.

That's when things get damaged microscopically

Stick-slip is a common phenomenon. It is responsible for everything from computer hard drive crashes and automobile failures, to squeaking doors and music

same thing happens with a violin string

Even if you're pulling the bow steadily, it's moving in hundreds or thousands of little jerks per second, which determine the sound you hear

Each little jerk, no matter how submicroscopic, is an impact, and over time the accumulation of these impacts can deform surfaces, causing irreparable damage—first microscopically, then growing to macroscopic

it's not easy to tell the difference between types of friction at the microscopic level

Smooth-sliding joints might feel the same as those undergoing stiction, or the even more harmful stick-slip, especially in the early stages of arthritis

when measured with an ultra-sensitive and high-resolution instrument like the SFA, each type of friction revealed its own characteristic profile

Smooth-sliding joints yielded an almost smooth constant line (friction force or friction trace

with stiction showed up as a peak, as the "sticking" was being overcome, followed by a relatively smooth line

stick-slip shows the jagged saw-tooth profile of two surfaces repeatedly pulling apart, sticking, and pulling apart again

these measurements could be recorded by placing an acoustic or electric sensing device around joints, giving a signal similar to an EKG.

this could be a good way to measure and diagnose damage to the cartilage

to measure the progression, or even the early detection of symptoms related to arthritis

Early detection of conditions like arthritis has been a priority for many years

the functioning of joints is more complicated

scientists will continue their work by studying synovial fluid—the lubricating fluid between two cartilage surfaces in joints

plays a major role in whether or not the surfaces wear and tear, and the synergistic roles of the different molecules (proteins, lipids, and polymers

all involved in lubricating and preventing damage to our joints.

a number of directions to take, both fundamental and practical

it looks as if we need to focus our research on finding ways to prevent stick-slip motion, rather than lowering the friction force

Anatomical evidence, however, points to it being a juvenile; adults may have been larger.

Until very recently, the United States was the epicenter for dinosaur diversity, but China surpassed the U.S. in 2007 in terms of species found

The anatomical features of the bones bear some resemblance to another Titanosaur that had been discovered by paleontologists in China in 1929

the team was able to identify a number of unique characteristics

The shoulder blade was

nearly 2 meters, with sides that were nearly parallel, unlike many other Titanosaurs whose scapulae bow outward

an unfused portion of the shoulder blade indicated to the researchers that the animal under investigation was a juvenile or subadult

The scapula was so long, indeed, that it did not appear to fit in the animal's body

if placed in a horizontal or vertical orientation

Instead

suggest the bone must have been oriented at an angle of 50 degrees from the horizontal.

a full-grown adult might be larger than this 50-60 foot long individual

The ulna and radius were well preserved, enough so that the researchers could identify grooves and ridges they believe correspond with the locations of muscle attachments in the dinosaur's leg

the vertebrae had large cavities in the interior that the team believes provided space for air sacs in the dinosaur's body

It's believed that dinosaurs, like birds, had air sacs in their trunk, abdominal cavity and neck as a way of lightening the body

the longest tooth they found was nearly 15 centimeters long

the discovery point to the fact that Titanosaurs encompass a diverse group of dinosaurs,

it was once thought that sauropods dominated herbivorous dinosaur fauna during the Jurassic but became almost extinct during the Cretaceous

n other parts of the world, particularly in South America and Asia, sauropod dinosaurs continued to flourish in the Cretaceous

Issus coleoptratus

juveniles

The researchers’ high-speed videos showed that the creatures

, is believed to be the first functional gearing system ever discovered in nature

The finding,

used electron microscopes and high-speed video capture to discover the existence of the gearing and figure out its exact function.

To jump, both of the insect’s hind legs must push forward at the exact same time

The reason for the gearing, they say, is coordination

have an intricate gearing system that locks their back legs together, allowing both appendages to rotate at the exact same instant, causing the tiny creatures jump forward.

cocked their back legs in a jumping position, then pushed forward, with each moving within 30 microseconds

if one tooth breaks, it limits the effectiveness of the design

30 millionths of a second

the skeleton is used to solve a complex problem that the brain and nervous system can’t

The gears are located at the top of the insects’ hind legs

and include 10 to 12 tapered teeth, each about 80 micrometers wide (or 80 millionths of a meter).

In all the Issus hoppers studied, the same number of teeth were present on each hind leg, and the gears locked together neatly

adults of the same insect species don’t have any gearing—as the juveniles grow up and their skin molts away

the adult legs are synchronized by an alternate mechanism (a series of protrusions extend from both hind legs, and push the other leg into action).

hypothesize that this could be explained by the fragility of the gearing

jump at speeds as high as 8.7 miles per hour

isn’t such a big problem for the juveniles, who repeatedly molt and grow new gears before adulthood

for the mature Issus, replacing the teeth would be impossible

There have been gear-like structures previously found on other animals

but they’re purely ornamental