Duke Research Blog

Following the people and events that make up the research community at Duke.

Category: Art (Page 2 of 3)

Cracking a Hit-and-Run Whodunit — With Lasers

The scratch was deep, two feet long, and spattered with paint flecks. Another vehicle had clearly grazed the side of Duke graduate student Jin Yu’s silver Honda Accord.

But the culprit had left no note, no phone number, and no insurance information.

Pump-Probe-Microscope-Pigment

Duke graduate student Jin Yu used laser-based imaging to confirm the source of a large scratch on the side of her car. Paint samples from an undamaged area on her Honda Accord (top left) and a suspected vehicle (top right) gave her the unique pump-probe microscopy signatures of the pigments on each car. The damaged areas of the Honda (bottom left) and the suspected vehicle on right (bottom right) show pigment signatures from both vehicles.

The timing of the accident, the location of the scratch, and the color of the foreign paint all pointed to a likely suspect: another vehicle in her apartment complex parking lot, also sporting a fresh gash.

She had a solid lead, but Yu wasn’t quite satisfied. The chemistry student wanted to make sure her case was rock-solid.

“I wanted to show them some scientific evidence,” Yu said.

And lucky for her, she had just the tools to do that.

As a researcher in the Warren Warren lab, Yu spends her days as scientific sleuth, investigating how a laser-based tool called pump-probe microscopy can be used to differentiate between individual pigments of paint, even if they appear identical to the human eye.

The team is developing the technique as a way for art historians and conservators peer under the surface of priceless paintings, without causing damage to the artwork. But Yu thought there was no reason the technique couldn’t be used for forensics, too.

“The idea popped into my mind — car paint is made up of pigments, just like paintings,” Yu said. “So, if I can compare the pigments remaining on my car with the suspected car, and they match up, that would be a pretty nice clue for finding the suspected car.”

Using a clean set of eyebrow tweezers, Yu carefully gathered small flecks of paint from her car and from the suspected vehicle and sealed them up inside individual Ziploc bags. She collected samples both from the scratched up areas, where the paint was mixed, and from undamaged areas on both cars.

She left a note on the car, citing the preliminary evidence and stating her plan to test the paint samples. Then, back at the lab, she examined all four samples with the pump-probe microscope. Unlike a standard optical microscope, this device illuminates each sample with a precisely timed series of laser pulses; each pigment absorbs and then re-emits this laser light in a slightly different pattern depending on its chemical structure, creating a unique signature.

Optical-Microscope-and-Note

After finding the gash on her Accord (top left), Yu left a note (top right) on the car that she suspected of having caused the accident. Under an optical microscope, samples from damaged areas on the cars show evidence of the same two kinds of paint (bottom). Yu used pump-probe microscopy to confirm that the pigments in the paint samples matched.

The samples from the undamaged areas gave her the characteristic pigment signatures from both of the two vehicles.

She then looked at the paint samples taken from the scratched areas. She found clear evidence of paint pigment from the suspected car on her Honda, and clear evidence of paint pigment from her Honda on the suspected car. This was like DNA evidence, of the automotive variety.

Fortunately, the owner of the suspect vehicle contacted Yu to confess and pay to have her car fixed, without demanding the results of the paint analysis. “But it was reassuring to have some scientific evidence in case she denied the accident,” Yu said.

Yu says she had no interest in forensic science when she started the investigation, but the experience has certainly piqued her curiosity.

“I had never imagined that I can use pump-probe microscopy for forensic science before this car accident happened,” Yu said. “But I think it shows some interesting possibilities.”

Kara J. Manke, PhD

Post by Kara Manke

Sandcastles of Stars Make Stable Structures

Sandcastles are not known for their structural stability; even the most steadfast seaside fortresses won’t survive a crashing wave or a bully’s kick.

But what if, instead of round grains of sand, you built your castle from tiny stars?

Duke graduate student Yuchen Zhao tests the stability of a tower made from six-armed stars or “hexapods.”

Duke graduate student Yuchen Zhao has spent the last year studying such “sandcastles of stars” — towers crafted from hundreds of six-armed stars or “hexapods” which bear a remarkable resemblance to the jacks you might have played with as a kid.

To build these towers, Zhao simply pours the stars into a hollow tube, and then removes the tube. But unlike columns of sand, these towers stand on their own, stay up when shaken, and can even bear up to twice their own weight.

“When you remove the support, you see that the star particles have really jammed together!” said Zhao. “Nobody understands exactly how this rigidity comes about.”

Sand is a classic example of a granular material, and like other types of granular materials — rice, flour, marbles, or even bags of jacks — it sometimes pours like a liquid, and other times “jams” up, forming a rigid solid.

The physics of jamming has been well-studied for round and spherical particles, says Duke physics professor Bob Behringer, an expert on granular materials who advises Zhao. But much less is understood about jamming in particles with more complex shapes, like hexapods.

“As soon as you move away from spheres, you can create jammed systems at the drop of a hat,” said Behringer. “People think they understand these systems, but there are still a lot of outstanding questions about how they behave: how do they break? Or how do they respond to shear stress?”

These questions aren’t only interesting to physicists, Behringer says. Architects Karola Dierichs and Achim Menges, collaborators on the project, are experimenting with using custom-designed granular materials, from hexapods to hooks, to create structures like walls and bridges.

Similar to a sandcastle or a bird’s nest, structures made this way can be porous, light, recyclable and even adaptable.

“One of their big ideas is, can you actually design a structure that could build itself or be constructed at random, rather than designing something very precise?” said Zhao.

Zhaos says that the first goal of his project was simply to explore the physical limits of towers built from hexapods. To do so, he constructed towers out stars ranging in size from 2 to 10 centimeters and made from two different materials. For each combination, he investigated how high he could build the tower before it collapsed. He then subjected the towers to various stressors, including vibration, tilting, and added weight.

One of the most surprising findings, Zhao said, was that the friction between the particles — whether they were made of smooth acrylic or rougher nylon — had the biggest impact on the stability of the towers. He also noted that when these towers collapse, they don’t just fall over in a heap, they fall apart in a series of mini avalanches.

CT-Scan of jacks

A 3D illustration of a tower of stars reconstructed from CT-scan data. The red dots indicate the points of contact between the stars. Image courtesy of Jonathan Barés.

The team has published this initial study, which they hope will be used as a “handbook of mechanical rules” to improve the design of aggregate structures, in a special edition of the journal Granular Matter.

As a next step in the experiment, Zhao and collaborator Jonathan Barés are using a CT scanner in the Duke SMIF lab to take detailed 3D pictures of the “skeletons” of these structures. With the data, they hope to find a better understanding of how all the individual contacts between stars add up to a stable tower.

“It is amazing to see how these particles can make stable structures capable of supporting big loads,” said Jonathan Barés, who is a former Duke postdoc. “Just changing a small property of the particles — their ability to interlock — creates a dramatic change in the behavior of the system.”

CITATION: “Packings of 3D stars: stability and structure.” Yuchen Zhao, Kevin Liu, Matthew Zheng, Jonathan Barés, Karola Dietrichs, Achim Menges, and Robert P. Behringer. Granular Matter, April 11, 2016. DOI: 10.1007/s10035-016-0606-4

Kara J. Manke, PhD

Post by Kara Manke

What Makes a Face? Art and Science Team Up to Find Out

From the man in the moon to the slots of an electrical outlet, people can spot faces just about everywhere.

As part of a larger Bass Connections project exploring how our brains make sense of faces, a Duke team of students and faculty is using state-of-the-art eye-tracking to examine how the presence of faces — from the purely representational to the highly abstract — influences our perception of art.

The Making Faces exhibit is on display in the Nasher Museum of Art’s Academic Focus Gallery through July 24th.

The artworks they examined are currently on display at the Nasher Museum of Art in an installation titled, “Making Faces: At the Intersection of Art and Neuroscience.”

“Faces really provide the most absorbing source of information for us as humans,” Duke junior Sophie Katz said during a gallery talk introducing the installation last week. “We are constantly attracted to faces and we see them everywhere. Artists have always had an obsession with faces, and recently scientists have also begun grappling with this obsession.”

Katz said our preoccupation with faces evolved because they provide us with key social cues, including information about another individual’s gender, identity, and emotional state. Studies using functional Magnetic Resonance Imaging (fMRI) even indicate that we have a special area of the brain, called the fusiform face area, that is specifically dedicated to processing facial information.

The team used eye-tracking in the lab and newly developed eye-tracking glasses in the Nasher Museum as volunteers viewed artworks featuring both abstract and representational images of faces. They created “heat maps” from these data to illustrate where viewers gazed most on a piece of art to explore how our facial bias might influence our perception of art.

This interactive website created by the team lets you observe these eye-tracking patterns firsthand.

When looking at faces straight-on, most people direct their attention on the eyes and the mouth, forming a triangular pattern. Katz said the team was surprised to find that this pattern held even when the faces became very abstract.

“Even in a really abstract representation of a face, people still scan it like they would a face. They are looking for the same social information regardless of how abstract the work is,” said Katz.


A demonstration of the eye-tracking technology used to track viewers gaze at the Nasher Museum of Art. Credit: Shariq Iqbal, John Pearson Lab, Duke University.

Sophomore Anuhita Basavaraju pointed out how a Lonnie Holley piece titled “My Tear Becomes the Child,” in which three overlapping faces and a seated figure emerge from a few contoured lines, demonstrates how artists are able to play with our facial perception.

“There really are very few lines being used, but at the same time it’s so intricate, and generates the interesting conversation of how many lines are there, and which face you see first,” said Basavaraju. “That’s what’s so interesting about faces. Because human evolution has made us so drawn towards faces, artists are able to create them out of really very few contours in a really intricate way.”

IMG_8354

Sophomore Anuhita Basavaraju discusses different interpretations of the face in Pablo Picasso’s “Head of a Woman.”

In addition to comparing ambiguous and representational faces, the team also examined how subtle changes to a face, like altering the color contrast or applying a mask, might influence our perception.

Sophomore Eduardo Salgado said that while features like eyes and a nose and mouth are the primary components that allow our brains to construct a face, masks may remove the subtler dimensions of facial expression that we rely on for social cues.

For instance, participants viewing a painting titled “Decompositioning” by artist Jeff Sonhouse, which features a masked man standing before an exploding piano, spent most of their time dwelling on the man’s covered face, despite the violent scene depicted on the rest of the canvas.

“When you cover a face, it’s hard to know what the person is thinking,” Salgado said. “You lack information, and that calls more attention to it. If he wasn’t masked, the focus on his face might have been less intense.”

In connection with the exhibition, Nasher MUSE, DIBS, and the Bass Connections team will host visiting illustrator Hanoch Piven this Thursday April 7th and Friday April 8th  for a lunchtime conversation and hands-on workshop about his work creating portraits with found objects.

Making Faces will be on display in the Nasher Museum of Art’s Academic Focus Gallery through July 24th.

Kara J. Manke, PhD

Post by Kara Manke

The Future of 3D Printing in Medicine

While 3D printers were once huge, expensive devices only available to the industrial elite, they have rapidly gained popularity over the last decade with everyday consumers. I enjoy printing a myriad of objects at the Duke Colab ranging from the Elder Wand to laptop stands.

One of the most important recent applications of 3D printing is in the medical industry. Customized implants and prosthetics, medical models and equipment, and synthetic skin are just a few of the prints that have begun to revolutionize health care.

3D printed prosthetic leg: “customizable, affordable and beautiful.”

Katie Albanese is a student in the Medical Physics Graduate Program who has been 3D printing breasts, abdominal skeletons, and lungs to test the coherent scatter x-ray imaging system she developed. Over spring break, I had the opportunity to talk with Katie about her work and experience. She uses the scatter x-ray imaging system to identify the different kinds of tissue, including tumors, within the breast. When she isn’t busy printing 3D human-sized breasts to determine if the system works within the confines of normal breast geometries, Katie enjoys tennis, running, napping and watching documentaries in her spare time. Below is the transcript of the interview.

How did you get interested in your project?

When I came to Duke in 2014, I had no idea what research lab I wanted to join within the Medical Physics program. After hearing a lot of research talks from faculty within my program, I ultimately chose my lab based on how well I got along with my current advisor, Anuj Kapadia in the Radiology department. He had an x-ray project in the works with the hope of using coherent scatter in tissue imaging, but the system had yet to be used on human-sized objects.

Could you tell me more about the scatter x-ray imaging system you’ve developed?

Normally, scatter in a medical image is actively removed because it doesn’t contribute to diagnostic image quality in conventional x-ray. However, due to the unique inter-atomic spacing of every material – and Bragg’s law – every material has a unique scatter signature. So, using the scattered radiation from a sample (instead of the primary x-ray beam that is transmitted through the sample), we can identify the inter-atomic spacing of that material and trace that back to what the material actually is to a library of known inter-atomic spacings.

Bragg diffraction: Two beams with identical wavelength and phase approach a crystalline solid and are scattered off two different atoms within it.

How do you use this method with the 3D printed body parts?

One of the first things we did with the system was see if it could identify the different types of human tissue (ex. fat, muscle, tumor). The breast has all of these tissues within a relatively small piece of anatomy, so that is where the focus began. We were able to show that the system could discern different tissue types within a small sample, such as a piece of excised human tissue. However, in order to use any system in-vivo, which is ideally the aim, you have to determine whether or not it works on a normal human geometry. Another professor in our department built a dedicated breast CT system, so we used patient scans from that machine to model and print an accurate breast, both in anatomy and physical size.

 

What are the three biggest benefits of the x-ray imaging system for future research? 

Main breast phantom used and a mammogram of that phantom with tissue samples in it

Main breast phantom used and a mammogram of that phantom with tissue samples in it

Coherent scatter imaging is gaining momentum as an imaging field. At the SPIE Medical Imaging Conference a few weeks ago in San Diego, there was a dedicated section on the use of scatter imaging (and our group had 3 out of 5 talks on the topic!). One major benefit is that it is noninvasive. There is always a need for a noninvasive diagnostic step in the medical field. One thing we foresee this technology being used for could be a replacement for certain biopsy procedures. For instance, if a radiologist finds something suspicious in a mammogram, a repeat scan of that area could be taken on a scatter imaging system to determine whether or not the suspicious lesion is malignant or not. It has the potential to reduce the number of unnecessary invasive (and painful!) biopsies done in cancer diagnosis.

Another thing we envision, and work has been done on this in our group, is using this imaging technique for intra-operative margin detection. When a patient gets a lumpectomy or mastectomy, the excised tissue is sent to pathology to make sure all the cancer has been removed from the patient. This is done by assessing whether or not there is cancer on the outer margins of the sample and can often take several days. If there is cancerous tissue in the margin, then it is likely that the extent of the cancer was not removed from the patient and a repeat surgery is required. Our imaging system has the potential to scan the entirety of the tissue sample while the patient is still open in the operating room. With further refinement of system parameters and scanning technique, this could be a reality and help to prevent additional surgeries and the complications that could arise from that.

What was the hardest or most frustrating part of working on the project? 

We use a coded aperture within the x-ray beam, which is basically a mask that allows us to have a depth-resolved image. The aperture is what tells us where the source of the scatter came from so that we can reconstruct. The location of this aperture relative to the other apparatus within our setup is carefully calibrated, down to the sub-millimeter range. If any part of the system is moved, everything must be recalibrated within the code, which is very time-consuming and frustrating. So basically every time we wanted to move something in our setup to make things better or more efficient, it was like we were redesigning the system from scratch.

 What is your workspace like?

Katie and the team at the AAPM (American Association of Physicists in Medicine) conference from this past summer in Anaheim, CA where she presented in a special session on breast imaging. From left to right: Robert Morris (also in the research lab and getting his degree in MedPhys), Katie, Dr. James Dobbins III (former program director and current Associate Vice Provost for DKU) and Dr. Anuj Kapadia, my advisor and current director of graduate studies in the program

Katie presented in a special session on breast imaging at the American Association of Physicists in Medicine conference this past summer in Anaheim, CA. From left to right: Robert Morris, also working in the lab; Katie; Dr. James Dobbins III, former program director and current Associate Vice Provost for Duke-Kunshan University; and Dr. Anuj Kapadia, Katie’s advisor and current director of graduate studies.

We have a working experimental lab within the hospital. It looks like any other physics lab you might come across- messy, full of wires and strange electronics. It is unique from other labs within the Medical Physics department because a lot of research that is done there focuses on image processing or radiation therapy treatment planning and can be done on just a computer. This lab is very hands-on in that we need to engineer the system ourselves. It is not uncommon for us to be using power tools or soldering or welding.

What do you like best about 3D printing? 

3D printing has become such a great community for creativity. One of my favorite websites now, called Thingiverse, is basically a haven for 3D printable files of anything you could ever dream of, with comments on the best printing settings, printers and inks. You can really print anything you want — I’ve printed everything from breasts, lungs and spines to small animal models and even Harry Potter memorabilia to add to my collection. If you can dream it, you can print it in three dimensions, and I think that’s amazing.

 

Anika_RD_hed100_2By Anika Radiya-Dixit

 

When the Data Get Tough, These Researchers Go Visual

Ever wondered what a cleaner shrimp can see?

Or how the force of a footstep moves from particle to particle through a layer of sand?

How about what portion of our renewable energy comes from wind versus solar power?

The winning submission, created by Nicholas School PhD candidate Brandon Morrison, illustrates the flow of agricultural and forestry crops from raw materials to consumer products. The colors correspond to the type of crop – brown for wood, green for vegetables, etc. – and the width of the lines correspond to the quantity of the crop. You can check out the full image and caption on the Duke Data Visualization Flickr Gallery.

The winning submission, created by Nicholas School PhD candidate Brandon Morrison, illustrates the flow of agricultural and forestry crops from raw materials to consumer products. The colors correspond to the type of crop – brown for wood, green for vegetables, etc. – and the width of the lines correspond to the quantity of the crop. You can check out the full image and caption on the Duke Data Visualization Flickr Gallery.

The answers to these questions and more are stunningly rendered in the entries to the 2016 Student Data Visualization Contest, which you can check out now on the Duke Data Visualization Flickr Gallery.

“Visualizations take advantage of our powerful ability to detect and process shapes to reveal detailed trends that you otherwise wouldn’t be able to see,” said Angela Zoss, Data Visualization Coordinator at Duke Data and Visualization Services (DVS), who runs the contest. “This year’s winners were all able to take very complex topics and use visualization to make them more accessible.”

One winner and two finalists were selected from the 14 submissions on the basis of five criteria: insightfulness, broad appeal, aesthetics, technical merit, and novelty. The submissions represent data from all areas of research at Duke – from politics and health to fundamental physics and biology.

“This year’s entrants showed a lot of sophistication and advanced scholarship,” Zoss said.  “We’re seeing more advanced graduate work and multi-year research projects that are really benefiting from visualization.”

Eric Monson, a Data Visualization Analyst with DVS, hopes the contest will inspire more students to consider data visualization when grappling with intricate data sets.

“A lot of this work only gets shared within courses or small academic communities, so it’s exciting to give people this opportunity to have their work reach a broader audience,” Monson said.

Posters of the winning submissions will soon be on display in the Brandaleone Lab for Data and Visualization Services in The Edge on the first floor of Bostock Library.

The second-place entry, by Art History PhD student Katherine McCusker, depicts an archaeological site in Viterbo, Italy. The colored lines indicate the likely locations of buried structures like walls, platforms, and pavement, based on an interpretation of data from ground-penetrating radar (represented by a dark red, yellow, white colormap). You can check out the full image and caption on the Duke Data Visualization Flickr Gallery.

The second-place entry, by Art History PhD student Katherine McCusker, depicts an archaeological site in Viterbo, Italy. The colored lines indicate the likely locations of buried structures like walls, platforms, and pavement, based on an interpretation of data from ground-penetrating radar (represented by a dark red, yellow, white colormap). You can check out the full image and caption on the Duke Data Visualization Flickr Gallery.

Kara J. Manke, PhD

Post by Kara Manke

 

Star Wars and Space Travel: The Study of Science through Popular Movies

Who says class has to be all about lectures and labs? Andrés Aragoneses, a quantum optics researcher at Duke, has created a class called “Science & Science Fiction” in conjunction with the Osher Lifelong Learning Institute at Duke (OLLI). The course explores hot science fiction topics through the study of famous movies – from Star Wars, to Independence Day, to The Martian.

Professor Aragoneses teaching the class about the Big Bang Expansion

Professor Aragoneses teaching the class about the Big Bang Expansion

The unconventional idea to use movies as the primary medium for the class was born during Professor Aragoneses’s time teaching in Spain. Physics professors at his university had found that in order to get students to follow their classes, they had to do more than just explain Newton’s law and demonstrate practice problems. So, they began to relate these complex topics to media that the students were familiar with — news, cinema, and comics.

Each week, the OLLI group watches small scenes of movies that use scientific concepts in their production, and then learns the true theories behind these concepts. Most movies are quite fantastic when it comes to their scientific aspects, and this leads to incorrect representations of cosmological, physical, and astronomical phenomena on the screen. Focusing on a single concept each class, Aragoneses debunks Hollywood myths about natural disasters, comets, solar flares, neutrinos, and magnetic fields (to name a few).

Astronauts traveling with fuel packing in "Mission to Mars"

Astronauts traveling with jet packs in “Mission to Mars”

One week, the class focused on the dynamics of travel in space, calling on “Mission to Mars” to provide them with their screen reference. In one particular scene, astronauts are walking on Mars, propelled by air coming out of their backs and pushing them forward. The class learned that due to the lack of frictional force in space, the astronauts would, in reality, never run out of fuel since they would not need to push as hard as the movie suggested, using up much less fuel. The popular movie reference allowed Aragoneses to easily segue into the topics of friction, Newton’s laws, and the reality of space travel for the remainder of the class, while still holding the students’ attention. The group also analyzed the scientifically impossible behavior of deadly neutrinos in scenes from “2012” to learn about their true movement, and watched parts of “Independence Day” to better understand meteors and atmospheric interferences.

Astrophysicist searching for new planets by analyzing star movements.

Astrophysicist searching for new planets by analyzing star movements.

Occasionally, Aragoneses uses scientifically sound movies to study different concepts. One scene in Star Wars features Obi-Wan searching for a planet he is not able to find in existing maps. Yoda explains to him that the movement of the other stars in the sky is suspicious, and reasons that something must exist in between, although Obi-Wan cannot see it. The scene demonstrates the true manner in which astrophysicists search for new planets; since they are so tiny, they analyze movements of surrounding stars to detect their presence rather than searching for the planets themselves. Clearly the Grand Jedi Master knew a thing or two about the real universe!

Aragoneses’s idea to teach the class in such a unique fashion has evidently captivated his students; they often return after the week with new questions, suggestions for future movie references, and an excitement to continue their exploration of elaborate scientific concepts. The class has been a learning experience for Aragoneses as well, as he has had the chance to watch movies he hadn’t previously seen, and develop a deeper understanding of the concepts he teaches. He has so thoroughly enjoyed his work on the class in fact, that he is considering continuing to teach for OLLI in the future.

For those who are interested in enrolling in one of Aragoneses’s future classes, or another class hosted by OLLI, please visit their website. The Institute teaches about 100 different courses that range in topic from history, to science, to politics, to religion. The courses are taught both by Duke professors, and by other individuals from the Durham area.

Anika Ayyar_100Post by Anika Ayyar

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