Resurrecting dinosaurs with medical scanners and 3D printers

CT scans and 3D printers are making it possible to see fossils that were previously inaccessible inside rock.

Accurate copies of fossilised bones can now be made from the combined use of computed tomography (CT) scans and 3D printers, according to a paper published in the journal Radiology.

The technique offers scientists a non-destructive way of transporting and handling rare or fragile fossils.

To protect such specimens from damage during transportation, the fossils are often stored in plaster jackets or casts. These jackets must be strong enough to protect the fossils, but should also separate easily from the specimen when removed.

It is during the removal of the plaster and surrounding sediment that the fossil is in danger of material loss or even destruction. This typically occurs when the plaster is stuck fast to the bone.

(A 3D print of a fossil (right) next to the original still inside a plaster jacket. Image: Courtesy of Radiology and RSNA)

A group of German researchers found that, by using CT and 3D printers, they could separate fossilised bone from its surrounding sediment matrix in a way that would not harm the specimen, then produce a 3D copy of it.

Applying this method to an unidentified fossil from the Museum für Naturkunde in Berlin, the researchers scanned the bone with a 320-slice multi-detector system to show up the different attenuation (absorption of radiation) through the bone and the surrounding sediment matrix, depicting clearly the fossilised vertebra.

The scan also provided information on the condition and integrity of the specimen, like otherwise unknown fractures, and helped the researchers build an accurate reconstruction of the fossil.

Then using a laser sintering system – a process which uses high-powered lasers to fuse materials by adding thin horizontal layers of plastic – an accurate 3D copy of the fossil was produced.

(An enlarged 3D copy of a 380 million year old coelacanth skull found near Fitzroy Crossing, Western Australia. Image: John Long)

The impact on palaeontology
According to Richard Brian Gunderman, a professor of radiology at Indiana University who was not involved in the study, CT scanners are able to determine the exact structural dimensions of an object, down to fractions of a millimetre.

This data can then be used to construct a replica so precise that objects of great historical interest, like Stradivarius violins, have been created to sound remarkably similar to the originals.

“Such a technology has been a boon to palaeontologists in the past few years,” said John Long, strategic professor in palaeontology at Flinders University.

“Once we relied on meticulous time-consuming methods to prepare delicate fossils out of the rock and, even then, we could only see their external features. Now, using high-resolution micro-CT scanners and synchrotrons [particle accelerators], we can investigate every nook and cranny of the fossil right down to individual cells and tissue structures without having to risk damaging the specimen.

“Combined with advanced 3D printing, we can now slice though the ancient fossil skulls and print them in halves showing the full anatomy in clear definition. This will no doubt revitalise palaeontology.”

(A 3D scan of a 380 million-year-old Gogonasus fish skull by Tim Senden and ANU Vizlab.)

Ahi Sema Issever, from the Charité Campus Mitte in Berlin and one of the study’s authors, explained: “The most important benefit of this method is that it is non-destructive so the risk of harming the fossil is minimal. In addition, not only does this method allow for a global exchange of rare fossils in any quantity, data on the specimens can also be digitally shared between research institutes, museums and schools while protecting the original fossil.”

Darren Curnoe, associate professor at the University of New South Wales, agreed, saying: “Famous fossils like the Taung Child in South Africa - the very first ancient ape-like creature found in our human evolutionary tree - has been quite badly damaged following almost 90 years of study by scientists.

“Almost everyone who sees the fossil wants to take a couple of measurements of their own, and by doing so, is damaging these priceless pieces of our collective heritage. We need to do better, and such technology might just be the answer.”

A note of caution
Although supportive of the technological breakthrough in this study, Professor Long warned that researchers must not rely too heavily on tomographic imagery and 3D printing to draw their conclusions.

“It is important to carefully study the preservational biases of the original fossil first to determine how reliable a computer-generated image will be. In some cases, replacement of bone by other minerals or the presence of solid inclusions can effect the quality of CT images and affect 3D printing results.

“Scientists still need to study the original specimens in detail first, and then make interpretations using CT tomography and 3D printing.”

(A scanned 400 million-year-old placoderm eye capsule found in Taemas near Canberra. Image: Tim Senden)

Associate Professor Curnoe agreed, saying: “Any model made from CT scans must properly distinguish actual bone from missing bone, or even from materials like plaster, that had been used in the past to reconstruct missing bones in the fossils. This is particularly important since most fossils found are incomplete or distorted.

“In the end, there is nothing like seeing the real thing to fully understand the anatomy and the state of preservation of a fossil. But, for the sort of work many scientists do, especially postgraduate students, 3D models would be incredibly useful at a time when funding can be very hard to get.”

Beyond fossils
Some experts speculate that the findings from this study will benefit the medical field, like building and fitting implants in orthopaedic surgery. Others feel that the technique could be used to model real bones and other tissues, such as cadavers that have been preserved in ice or peat bogs.

Martin Baumers, a research fellow at the University of Nottingham, would like to see the implementation of a virtual library and data infrastructure for such 3D data and designs. He believes that it would aid collaborative research, allowing experts from different disciplines to share and retrieve 3D models for 3D printing or other scientific, even commercial, usage.

For Professor Long, the biggest breakthrough will come when palaeontologists possess the ability to make portable machines to take into the field and scan fossils, still buried under the rock layers, to determine the full extent of the fossil before excavating it.

This article was originally published at The Conversation. Read the original article.The Conversation

A scan of a 380million-year-old tooth from a fossil shark. (Image: Tim Sendon)
ILONA WELLMANN/MILLENNIUM IMAGES, UK
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How the internet has democratised pornography

With people now free to circumvent the big studios, different bodies, tastes and even pubic hair styles are being represented online.

Our opinions and tastes are influenced by the media we consume: that much is obvious. But although it’s easy to have that conversation if the medium we are discussing is “safe for work”, pornography carries so much stigma that we only engage with it on simple terms. Porn is either “good” or “bad”: a magical tool for ­empowerment or a destructive influence on society. Many “pro-porn” campaigners shy away from nuanced critique, fearing it could lead to censorship. “Anti-porn” campaigners, convinced that porn is harmful by definition, need look no further than the mainstream tube sites – essentially, aggregators of clips from elsewhere – to gather examples that will back them up.

When we talk about the influence of porn, the emphasis is usually on a particular type of video – hardcore sex scenes featuring mostly slim, pubic-hairless women and faceless men: porn made for men about women. This kind of porn is credited with everything from the pornification of pop music to changing what we actually do in bed. Last year the UK government released a policy note that suggested porn was responsible for a rise in the number of young people trying anal sex. Although the original researcher, Cicely Marston, pointed out that there was no clear link between the two, the note prompted a broad debate about the impact of porn. But in doing so, we have already lost – by accepting a definition of “porn” shaped less by our desires than by the dominant players in the industry.

On the day you read this, one single site, PornHub, will get somewhere between four and five million visits from within the UK. Millions more will visit YouPorn, Tube8, Redtube or similar sites. It’s clear that they’re influential. Perhaps less clear is that they are not unbiased aggregators: they don’t just reflect our tastes, they shape what we think and how we live. We can see this even in simple editorial decisions such as categorisation: PornHub offers 14 categories by default, including anal, threesome and milf (“mum I’d like to f***”), and then “For Women” as a separate category. So standard is it for mainstream sites to assume their audience is straight and male that “point of view” porn has become synonymous with “top-down view of a man getting a blow job”. Tropes that have entered everyday life – such as shaved pubic hair – abound here.

Alongside categories and tags, tube sites also decide what you see at the top of their results and on the home page. Hence the videos you see at the top tend towards escalation to get clicks: biggest gang bang ever. Dirtiest slut. Horniest milf. To find porn that doesn’t fit this mould you must go out of your way to search for it. Few people do, of course, so the clickbait gets promoted more frequently, and this in turn shapes what we click on next time. Is it any wonder we’ve ended up with such a narrow definition of porn? In reality, the front page of PornHub reflects our desires about as accurately as the Daily Mail “sidebar of shame” reflects Kim Kardashian.

Perhaps what we need is more competition? All the sites I have mentioned are owned by the same company – MindGeek. Besides porn tube sites, MindGeek has a stake in other adult websites and production companies: Brazzers, Digital Playground, Twistys, PornMD and many more. Even tube sites not owned by MindGeek, such as Xhamster, usually follow the same model: lots of free content, plus algorithms that chase page views aggressively, so tending towards hardcore clickbait.

Because porn is increasingly defined by these sites, steps taken to tackle its spread often end up doing the opposite of what was intended. For instance, the British government’s Digital Economy Bill aims to reduce the influence of porn on young people by forcing porn sites to age-verify users, but will in fact hand more power to large companies. The big players have the resources to implement age verification easily, and even to use legislation as a way to expand further into the market. MindGeek is already developing age-verification software that can be licensed to other websites; so it’s likely that, when the bill’s rules come in, small porn producers will either go out of business or be compelled to license software from the big players.

There are glimmers of hope for the ethical porn consumer. Tube sites may dominate search results, but the internet has also helped revolutionise porn production. Aspiring producers and performers no longer need a contract with a studio – all that’s required is a camera and a platform to distribute their work. That platform might be their own website, a dedicated cam site, or even something as simple as Snapchat.

This democratisation of porn has had positive effects. There’s more diversity of body shape, sexual taste and even pubic hair style on a cam site than on the home page of PornHub. Pleasure takes a more central role, too: one of the most popular “games” on the webcam site Chaturbate is for performers to hook up sex toys to the website, with users paying to try to give them an orgasm. Crucially, without a studio, performers can set their own boundaries.

Kelly Pierce, a performer who now works mostly on cam, told me that one of the main benefits of working independently is a sense of security. “As long as you put time in you know you are going to make money doing it,” she said. “You don’t spend your time searching for shoots, but actually working towards monetary gain.” She also has more freedom in her work: “You have nobody to answer to but yourself, and obviously your fans. Sometimes politics comes into play when you work for others than yourself.”

Cam sites are also big business, and the next logical step in the trickle-down of power is for performers to have their own distribution platforms. Unfortunately, no matter how well-meaning your indie porn project, the “Adult” label makes it most likely you’ll fail. Mainstream payment providers won’t work with adult businesses, and specialist providers take a huge cut of revenue. Major ad networks avoid porn, so the only advertising option is to sign up to an “adult” network, which is probably owned by a large porn company and will fill your site with bouncing-boob gifs and hot milfs “in your area”: exactly the kind of thing you’re trying to fight against. Those who are trying to take on the might of Big Porn need not just to change what we watch, but challenge what we think porn is, too.

The internet has given the porn industry a huge boost – cheaper production and distribution, the potential for more variety, and an influence that it would be ridiculous to ignore. But in our failure properly to analyse the industry, we are accepting a definition of porn that has been handed to us by the dominant players in the market.

Girl on the Net writes one of the UK’s most popular sex blogs: girlonthenet.com

This article first appeared in the 16 February 2017 issue of the New Statesman, The New Times