UCR: Graduate student constructs “human colon simulation”

Ian Marcus, a former graduate student from UCR’s Bourns College of Engineering, spent nearly a year constructing a replica of a human colon, septic tank and groundwater. According to UCR Today, through comparisons of his own work with researchers who worked with isolated bacteria, Marcus discovered that “the E. coli strain in the microbial community may be less mobile in aquatic environments and more prone to biofilm that than the isolated strain.”

In an effort to gain a more comprehensive understanding of the ways bacteria impacts the environment, Marcus “feeds” the colon thrice a day to simulate human digestion. He aims to show that researchers should study microorganisms in conditions as close as possible to their natural ones. Since biofilm is essentially a refuge from the environment, the E. coli lingers longer in the environment. When biofilm matures, bacteria colonize another surface and “could potentially linger longer and over a long period of time, travel greater distances in the groundwater,” Marcus explained.

Prior to Marcus’s idea and creation, scientists typically studied bacteria under ideal and isolated environments. The problem with this, however, is that bacteria proliferate in microbial communities along with archaea, fungi, protozoa and other microorganisms. Bacteria life cycles and communities can now be studied from the human colon acting as a conduit for water treatment and groundwater. Marcus is the first to combine the simulations of a human colon and aquatic environments.

In response to his research, UCR Associate Professor of Chemical and Environmental Engineering Dr. Sharon Walker expressed, “Ian’s work has provided critical new insight into how microbial communities behave in wastewater treatment and contribute to biological contamination of water, which really changes the paradigm of how we do research and manage our water resources.”

UCLA: Study shows no correlation between ADHD and substance abuse

Attention-deficit hyperactivity disorder, commonly known as ADHD, affects approximately five to 10 percent of the U.S. children population. A recent study conducted by UCLA psychologists showed that ADHD medication such as Retalin and Adderall have no observable correlation with the development of substance abuse problems.

The comprehensive assessment included 15 long-term studies in which psychologists Kathryn Humphreys and Steve S. Lee followed over 2,500 children, eight years old on average, for 12 years into young adulthood.

The findings concluded that “children were neither more likely nor less likely to develop alcohol and substance-use disorders as a result of being treated with stimulant medication,” Humphreys said. “However, later substance use is usually not the only factor parents think about when they are choosing treatment for their child’s ADHD.”

The study shows that stimulant medication is unlikely to increase a child’s likelihood of substance abuse in the future, but senior author Lee warns that “saying that all parents need not be concerned about the use of medication for their children is an overstatement … parents should consult with the prescribing physician about potential side effects and long-term risks.”

In 2011, a separate UCLA psychology research indicated that children diagnosed with ADHD are two to three times more likely to develop substance abuse problems than other children. Though the recent study does not oppose the 2011 findings, researchers state that children who take ADHD medication are not more prone to drug addictions to nicotine, marijuana, cocaine and other substances.

The study is published in journal JAMA Psychiatry, an international peer review journal consisting of medical research. Lee and Humphreys plan to publish three additional research articles in the future.

UC Davis: Stream pebbles suggest possibility of life on Mars

Curiosity, the car-sized rover that explores the Gale Crater on Mars, found, examined and took high-resolution images of pebble-rich slabs of rock at three locations known as Goulburn, Link and Hottah. Because of the pebbles’ size, roundness and other characteristics, researchers were able to conclude that the pebbles had been transported by water and deposited over two billion years ago. UC Davis geologist Dawn Sumner is a co-investigator for NASA’s Mars Science Laboratory Team and co-author of a study surrounding the remnants of life on Mars.

“The main reason we chose Gale Crater as a landing site was to look at the layered rocks at the base of Mount Sharp, about five miles away,” Sumner said in a press release. “These sorts of pebbles are likely because of that environment [with flowing water]. So while we didn’t choose Gale Crater for this purpose, we were hoping to find something like this.”

The roundness indicates that a stream once flowed through Mars, as round pebbles of such small size are known to form only after being transported extensively through water. The finding is the first piece of evidence that suggests water once flowed on Mars, since chemical reactions require water molecules in order to create living organisms.

Sumner had a critical role in choosing Gale Crater as Curiosity’s landing site. She expressed that finding the rounded pebbles was a matter of landing in the right place, as the red planet is roughly half the size of Earth and there is much to explore. Sumner also receives credit for coordinating the first scientific interpretations of the images and directing Curiosity to take photographs. She currently works on the mission from UC Davis but will soon go on sabbatical in order to continue working from the Jet Propulsion Laboratory.