The physics of icicles and our lumpy universe

Everyone knows that no two snowflakes are alike, but what about icicles? Physicist Stephen Morris built an icicle-making machine in his University of Toronto lab to tackle this question by systematically studying the shape of icicles and how they grow. (See video above). His research is not just fascinating physics. It could also have implications for preventing dangerous ice formations on airplane wings or power lines.

And icicles are just the tip of the problem. The entire universe is not uniform, instead it’s “a kind of foam or lumpy mass,” Morris says.

Morris is in Atlanta this week, where he will be giving talks about pattern formations in nature, going back to the lumps that developed in the primordial soup of early Earth. You can catch him in a public lecture tonight, Feb. 4 at 6 pm at Georgia Tech, and in an Emory physics colloquia tomorrow, Feb. 5 at 2:30 pm.

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Catch a rising star of ichnology

A sea star makes a trail on a barrier island beach, from the book "Life Traces of the Georgia Coast" by Anthony Martin.

Emory ichnologist Tony Martin drew a standing-room-only crowd on Saturday for his Atlanta Science Tavern talk about tracks, burrows, trails, nests, tooth marks, feces and other signs left by plants and animals. Who wouldn't want to follow an expert on tracks?

Here’s an excerpt from a post Martin wrote about his work for the “Wonders and Marvels” blog:

“In reality, the majority of ichnologists ignore humans, and more often use their observations of modern non-human traces as guides for traveling back in time to interpret the products of behavior from earth history. This is how we can interpret when (and why) a trilobite stopped and changed its direction while burrowing along a Paleozoic seafloor more than 400 million years ago. This is how we figure out what a dinosaur was eating on a given day during the Mesozoic Era, and that dung beetles were living with those dinosaurs, making use of the digested part of that dinosaur’s meal. This is how we identify the size and species of fish that swam along a lake bottom more than 50 million years ago, despite it having left only marks from its fins and mouth. Given nearly 10 million species of modern life-forms and their behaviors to consider, four billion years of life history, and innumerable trace fossils that resulted from that life, why should we waste our time being anthropocentric, or otherwise let ourselves be distracted by just our species in the here and now?”

Martin will give another talk on February 5 at the Decatur Library, where he will also be signing copies of his new book, “Life Traces of the Georgia Coast.” And on February 24, Martin will be the guest lecturer at Andalusia, the Milledgeville farm of Flannery O’Connor.

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Lake-bed trails tell ancient fish story
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Burrow into a good book on wildlife traces
Insider's guide to Georgia barrier islands

Canine brain-tumor treatment trials may help humans

Following a seizure, Petey the pit bull was diagnosed with a brain tumor. He is doing well after undergoing treatment in a pilot trial in 2011.

By Janet Christenbury
Woodruff Health Sciences Center

The American Kennel Club Canine Health Foundation, Inc., has awarded the University of Georgia (UGA) College of Veterinary Medicine and Emory University a $119,000 grant over three years to test a newly developed experimental drug to treat dogs with naturally-occurring brain tumors, following partial surgical removal of those tumors.

The goal of the research is to help translate new brain cancer therapies to humans by assessing results in dogs with similar diseases. According to the researchers, the tumors in dogs, known as spontaneous gliomas, are very similar to human malignant brain tumors both by imaging and biology, and both tend to grow back rapidly. The poor prognosis for dogs with gliomas is similar to human patients. The researchers are hoping the novel treatment being tested will slow down tumor growth.

A seven-year-old pit bull named Petey was the first dog enrolled in the initial pilot trial at UGA in 2011. Following discovery of a brain tumor after a seizure, Petey underwent surgery in September 2011 to remove a portion of the tumor. Simon Platt, a professor of veterinary neurology at UGA, performed the surgery and diagnosed Petey with a glioma. After surgery and for three days, an investigational drug was directly infused into the glioma tumor area via catheters, targeting any residual tumor cells. Petey underwent blood testing and complete neurologic testing confirming no toxicity of the therapeutic agent.

Six weeks after surgery, Petey had a follow-up MRI that revealed the therapeutic agent still within the remaining brain tumor. Petey had another MRI five months after surgery showing a marked reduction in tumor size. Petey is now seizure-free and doing well 15 months after surgery.

Read more.

Penicillin, not the pill, may have launched the sexual revolution

The 1950s were not as prudish as they seemed on the surface, says economist Andrew Francis. 

By Carol Clark

The rise in risky, non-traditional sexual relations that marked the swinging ‘60s actually began as much as a decade earlier, during the conformist ‘50s, suggests an analysis recently published by the Archives of Sexual Behavior.

“It’s a common assumption that the sexual revolution began with the permissive attitudes of the 1960s and the development of contraceptives like the birth control pill,” notes Emory University economist Andrew Francis, who conducted the analysis. “The evidence, however, strongly indicates that the widespread use of penicillin, leading to a rapid decline in syphilis during the 1950s, is what launched the modern sexual era.”

As penicillin drove down the cost of having risky sex, the population started having more of it, Francis says, comparing the phenomena to the economic law of demand: When the cost of a good falls, people buy more of the good.

“People don’t generally think of sexual behavior in economic terms,” he says, “but it’s important to do so because sexual behavior, just like other behaviors, responds to incentives.”

Syphilis reached its peak in the United States in 1939, when it killed 20,000 people. “It was the AIDS of the late 1930s and early 1940s,” Francis says. “Fear of catching syphilis and dying of it loomed large.”

Penicillin was discovered in 1928, but it was not put into clinical use until 1941. As World War II escalated, and sexually transmitted diseases threatened the troops overseas, penicillin was found to be an effective treatment against syphilis.

“The military wanted to rid the troops of STDs and all kinds of infections, so that they could keep fighting,” Francis says. “That really sped up the development of penicillin as an antibiotic.”

Right after the war, penicillin became a clinical staple for the general population as well. In the United States, syphilis went from a chronic, debilitating and potentially fatal disease to one that could be cured with a single dose of medicine.

From 1947 to 1957, the syphilis death rate fell by 75 percent and the syphilis incidence rate fell by 95 percent. “That’s a huge drop in syphilis. It’s essentially a collapse,” Francis says.

In order to test his theory that risky sex increased as the cost of syphilis dropped, Francis analyzed data from the 1930s through the 1970s from state and federal health agencies. Some of the data was only available on paper documents, but the Centers for Disease Control and Prevention (CDC) digitized it at the request of Francis.

For his study, Francis chose three measures of sexual behavior: The illegitimate birth ratio; the teen birth share; and the incidence of gonorrhea, a highly contagious sexually transmitted disease that tends to spread quickly.

“As soon as syphilis bottoms out, in the mid- to late-1950s, you start to see dramatic increases in all three measures of risky sexual behavior,” Francis says.

While many factors likely continued to fuel the sexual revolution during the 1960s and 1970s, Francis says the 1950s and the role of penicillin have been largely overlooked. “The 1950s are associated with prudish, more traditional sexual behaviors,” he notes. “That may have been true for many adults, but not necessarily for young adults. It’s important to recognize how reducing the fear of syphilis affected sexual behaviors.”

A few physicians sounded moralistic warnings during the 1950s about the potential for penicillin to affect behavior. Spanish physician Eduardo Martinez Alonso referenced Romans 6:23, and the notion that God uses diseases to punish people, when he wrote: “The wages of sin are now negligible. One can almost sin with impunity, since the sting of sinning has been removed.”

Such moralistic approaches, equating disease with sin, are counterproductive, Francis says, stressing that interventions need to focus on how individuals may respond to the cost of disease.

He found that the historical data of the syphilis epidemic parallels the contemporary AIDS epidemic. “Some studies have indicated that the development of highly active antiretroviral therapy for treating HIV may have caused some men who have sex with men to be less concerned about contracting and transmitting HIV, and more likely to engage in risky sexual behaviors,” Francis says.

“Policy makers need to take into consideration behavioral responses to changes in the cost of disease, and implement strategies that are holistic and longsighted,” he concludes. “To focus exclusively on the defeat of one disease can set the stage for the onset of another if preemptive measures are not taken.”

Images are vintage health messages from NIH National Library of Medicine.

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Your brain, in love and in lust

For this chemist, science never gets old

"We are pretty close to having a final answer, but we don't have it yet," says John Codington of the quest to develop better ways to detect cancer.

By Mary Loftus

Having peppermint tea and crackers at a small table in the break room of Emory’s Whitehead Biomedical Research Building, John Codington looks out the window onto a crisp November day. The ninety-three-year-old chemist is wearing an orange sweater bright enough to eclipse the fall foliage. He has his own lab space just down the hall, where he comes nearly every day to work in cancer research.

The railroad tracks running by the Depot café are just visible through the trees. “That used to be a passenger stop when I went to school here,” he says. Codington’s journey has taken him full circle, from Atlanta, where his family moved when he was one, to college at Emory, to the University of Virginia’s malaria research program, to the National Institutes of Health, to Europe, to faculty positions at Cornell and Harvard, to private biotech companies, and back to Emory.

Cancer cells with antibodies.

His primary research concerns the chemical changes in cell surface glycoproteins associated with immunoresistance in tumor cells, and his goal is to develop a diagnostic assay of sera to detect the presence of a carcinoma (cancer found in epithelial tissues). He hopes to develop a better, more reliable, and consistent way to detect most cancers, preferably at the earliest stages. “The test must be robust and suitable for clinical use,” he says.

Codington’s lab isolated epiglycanin, and recognized that antibodies to epiglycanin signaled a cancer-specific substance in the blood of carcinoma patients. He has worked since to improve the diagnostic assay by making it more stable and consistent—a quest he plans to continue as long as he is able. “We isolated the active component of epiglycanin, which I call Emorin, for Emory,” says Codington, who admits to feeling more himself in a lab coat than street clothes. “We are pretty close to having the final answer but we don’t have it yet.”

Difficulties abound. Cancer, he says, is so close to being normal that many aspects of a cancer cell are present in normal cells. Also, when dealing with human serum, you are dealing with the entire history of each individual. “If they have had measles, or mumps, they have those antibodies. All of these things come to bear,” Codington says, “That’s why it’s taking so long, and why no one else has found it.”

Read more about Codington's work and life. 

Photo of John Codington by Kay Hinton.