The Beckman Institute Graduate Student Seminar Series presents the work of outstanding graduate students working in Beckman research groups. The seminars begin at Noon in Beckman Institute Room 1005 and are open to the public. Lunch will be served.
Information Foraging across the Life Span: Search and Switch in Unknown Patches
Jessie Chin
In everyday life, people often face the decisions, “to go or not to go?” and “where to go?” For example, in apartment hunting, people need to decide if they want to continue visiting new apartments or to choose the current one. Information is distributed in clusters as patches in the wild. Human beings, as information consumers, do not have enough time and computational abilities to visit every information patch for finding useful information from multiple resources. Researchers used the analogue of how animals forage for food among patches in the wild to explain how people find information among multiple information resources in the world (Pirolli & Card, 1999).
The current study examined the effects of task environments and individual differences in information uptake and switch behavior in an information foraging task in which young and old participants attempted to maximize the number of items found in a set of 4 word search puzzles on an iPad. Mixed effects modeling was used to estimate the rates of information gain (RIG) for each participant suggesting that the information uptake grew differently in various task environments and differed with the general knowledge of information seekers. Results also showed that people of different ages switched among information patches differently whose perseverance was associated with their RIG. The tradeoff between exploration and exploitation for maximizing information gain was also discussed.
Biography: Jessie Chin is a Doctorate student in Educational Psychology and graduate fellow at Beckman Institute for Advanced Science and Technology who earned her Master Science degree in Human Factors at the University of Illinois at Urbana Champaign.
Mesenchymal Stem Cells Contribute to Vascular Growth in Skeletal Muscle in Response to Eccentric Exercise
Heather Huntsman
Tissue health is critically dependent on vascularization to support growth and function following injury. In addition to multiple implications in the regenerative potential of other tissues, mesenchymal stem cells have been shown to promote vessel formation both in vivo and in vitro. Our recent work has established that transgenic overexpression of the α7 integrin in skeletal muscle (α7Tg ) can enhance the presence of Sca-1+CD45- mesenchymal stem cells (mMSCs) which facilitate myogenesis. PURPOSE: The purpose of this study was to determine the extent to which angiogenesis and/or arteriogenesis is increased in α7Tg muscle following an acute bout of eccentric exercise and elucidate a role for mMSCs in this event. METHODS: mMSCs were isolated from α7Tg muscle by fluorescent activated cell sorting (FACS) and pericyte markers were examined by flow cytometry. Wild type (WT) and α7Tg mice (5 wk) were subjected to a single bout (30min) of downhill running exercise. Additionally, DiI-labeled mMSCs were injected into WT mice. Measures of angiogenesis and vessel growth were evaluated by immunohistochemistry. RESULTS: A large percentage of isolated mMSCs were positive for pericyte markers. DiI-labeled mMSCs injected into WT muscle migrated to the vascular niche and incorporated directly into vessels. Although capillary:fiber ratio, capillary density and tortuosity index did not increase, the number of large vessels was significantly increased in α7Tg muscle following exercise (p<0.05; 7 days post exercise bout) and in WT muscle receiving mMSC transplantation (P<0.05; 48%). CONCLUSION: This study demonstrates that mMSCs contribute to vascular growth in skeletal muscle in response to eccentric exercise, and that this adaptation is coordinated with increased myogenesis previously reported. Well-orchestrated responses similar to this may be a key mechanism in the successful regeneration of several tissue types.
*Supported by grants from the National Science Foundation, and the Ellison Medical Foundation.
Biography: I obtained my bachelors from Bethel College and masters from George Washington University, and both degrees were in Exercise Science. I am currently a third year PhD student in the department of Kinesiology and Community Health, and a second year National Science Foundation IGERT pre-doctoral fellow. Working for Dr. Marni Boppart in a Molecular Muscle Physiology lab, the focus of my research is the role of the α7β1 integrin and mesenchymal-like, adult stem cells in skeletal muscle regeneration. Using exercise as a stimulus for muscle generation I am very interested in both microenvironment and vascular changes that improve muscle quality and function. By understanding the mechanisms responsible for these changes I would like to one day develop a viable stem cell therapy that can be used in an aged or diseased population to improve muscle function. My interests outside of the lab include training for and participating in both running and triathlon endurance races.
