Brown researchers recently found new insight into how bacteria swim through fluids, according to an Aug. 12 University press release.
The researchers discovered a relationship between how coiled the bacteria’s spring-shaped flagellum is and the speed with which bacteria can move through viscous fluids. Unlike humans, who move most easily through fluids with low viscosity, bacteria move with greater ease through viscous substances, such as mucus or cervical fluid, the researchers said in the release. This is because viscous fluids are filled with polymers, which the bacterium push off of with their spiral flagella to propel themselves forward.
The researchers found themselves in a “really interesting fluid-dynamics problem,” said Thomas Powers, professor of engineering and physics and one of the study’s authors, in the release. The team’s computing led them to find that the tightness of the coil — the “pitch angle” — of the flagellum’s helix determines the bacteria’s speed in viscous fluids. The higher the pitch angle, the tighter the coil, and the faster the bacteria cruises through viscoelastic fluids, according to the release.
The findings could shine new light on issues of infection and fertility, which both involve bacterial swimming, according to the release.
Ice on Mars
Brown researchers have developed a new explanation for a unique type of crater found on Mars, according to an Aug. 5 University press release. More than 600 ejecta craters — featuring two distinct layers that form rings around the impaction site — have puzzled planetary geologists since the 1970s, according to the release. But James Head, professor of geological sciences, and David Kutai Weiss GS propose the Martian surface was once covered with meters of glacial ice, a unique surface that led to the strange double-layered rings around ejecta craters.
They propose that when the impact that caused the crater hit Mars’ icy surface, rock and debris flew away from the impact site to create the crater, according to the release. But because of the slippery ice surface of Mars, the debris didn’t stay put on the rim of the crater — it slid down the crater’s icy sides and formed the unusual double layer.
The findings “could tell us a lot about the history of the Martian climate on a global scale,” Weiss said.
Psychotherapy on the decline
The decline of psychotherapy to treat individuals with mental health problems may be due to the field’s failure to embrace evidence-based techniques, according to a special issue in Clinical Psychology Review, edited by Brandon Gaudiano and Ivan Miller, professors of psychiatry and human behavior.
In the review, the professors argue that the psychotherapy field has not quantified and communicated the evidence backing its practice, leading to psychotherapy’s declining presence in the mental health treatment world, according to a University press release. At the same time, the pharmaceutical industry has backed up its treatment practice with mounds of biological evidence, winning the attention of doctors, politicians and insurance companies, according to the release.
Between 1998 and 2007, the fraction of mental health patients in outpatient facilities receiving just psychotherapy decreased by about five percent, while the proportion of patients with medication-only treatment increased about 13 percent, according to the release.
Miller and Gaudiano concluded that the psychotherapy field should embrace scientific studies, and they highlighted mobile technology as a new opportunity for psychotherapists to deliver care and fold into health care teams, according to the release.