DUJS EVENT HIGHLIGHT
DUJS Science Lecture Series: MythBusters
As fall 2011 came to a close, Dartmouth Undergraduate Journal of Science held its termly DUJS Science Lecture Series—co-sponsored with Dartmouth Society of Biological Sciences—in honor of its newest fall issue. More than fifty students and faculty members attended the event, hosted by DUJS President Alice Pang ’12 with the help from DUJS’s Managing Editor Derek Racine ‘14, Publicity Relations Officer Diana Pechter ‘12 and Editor-in-Chief Andrew Zureick ‘13.
The event was composed of two lectures centered on the theme of DUJS’s newest issue, “Mythbusters.” Roger Sloboda—the Dartmouth Ira Allen Eastman Professor of Biology and the biology faculty advisor to DUJS—shed new light on the most current research on Flagellar Hip Complex and mused on the ongoing research on cell biology. Thalia Wheatley, a Dartmouth assistant professor of Psychological and Brain Sciences and the highlight of DUJS’s “Faculty Spotlights,” spoke about some of the foundations of hypnosis, her own contributions to this growing brain of brain studies and some of the most common misconceptions and the historical stigma associated with her research.
Wheatley’s presentation was followed by an actual hypnosis demonstration given to the entire audience. For thirty minutes, the audience listened attentively to the sound of her voice. Many participants who had unwittingly fallen under the influence of hypnosis were unable to raise their arms or to separate their interlocked fingers.
The event’s videocast is found on the DUJS website.
ENGINEERING
Energy Efficiency: A Look at the Class of ’78 Life Sciences Building
David Madigan, vice president of van Zelm Engineers, discussed the energy-efficient structure of the newly developed Class of ’78 Life Sciences (LSC) Building in a Jones Seminar. The building, whose design and construction was led by Madigan’s firm, is expected to receive a platinum LEED (Leadership in Energy and Environmental Design) award, signifying its overwhelmingly positive environmental impact.
Madigan’s firm worked to promote the greatest efficiency in factors that cause the greatest energy consumption for laboratory structures. The following list includes three significant energy-use problems and their complementing technological solutions:
1. High performance envelope: Much of the heat produced in large buildings is lost through weak insulation in the walls and roof. By using a continuous Spray Polyurethane Foam (SPF) insulation, a three-inch deep foam covers and seals all potential cracks, allowing for a higher thermal energy retention rate.
2. Controlled lighting: The LSC makes use of new technology called the Neutron Echo System, which contains a complex network of timers and sensors that continuously modulate lighting levels in the space to keep it consistent throughout the day. Thereby, electricity use during daylight hours is significantly less than at night, while the light experienced by the building’s occupants is exactly the same.
3. Heat recovery: The LSC’s Enthalpy Wheel draws thermal energy from exhaust steam and reuses 65–80% of the latent heat to warm the building. This device alone saves the College over $600,000 per year.
Ultimately, the Class of ’78 Life Sciences Building is an innovative and environmental achievement for both Madigan’s firm and the College. The building’s future looks towards solar panel roofing for hot water heating and an overall predicted 54.7% reduction in energy use compared to an average building of the same size. Only time will tell what new inventive and energy-efficient technologies will come to dominate the College’s landscape.
BIOLOGY
Changes in Genome Copy Number and Stability in Development
Understanding how DNA is replicated and how chromosomes are pulled apart is a significant issue with respect to human health. This subject has particular relevance for cancer, as defects in both of these processes are fundamental causes of cells going into the cancerous state of uncontrolled proliferation. The fruit fly is a model organism, because all of the genes that control these processes are common to both flies and humans.
Terry Orr-Weaver, professor of biology at MIT and featured speaker of The Distinguished Basic Science Lecture, uses the fruit fly in her lab to understand DNA repair and replication mechanisms. One of the defects that occurs during DNA replication is an increase in gene copy number, which is developmentally controlled by the repression of replication initiation and fork progression. Gene amplification results from replication stress, and genomic approaches have been taken to identify the origins and factors that stall replication forks.
In understanding the role of increasing the copy number for development, the Orr-Weaver lab has found relevance in development. Orr-Weaver is currently investigating the cross-talk that may be occurring between the neuronal mass. There may be an increase in gene copy number to accommodate the rapidly increasing neuronal mass as neuroblasts divide. Future studies include further defining the relationship between changes in gene copy number and development, as well as developing a strategy for organogenesis.
CHEMISTRY
Bioorganometallic Chemistry and Rhenium-based Contrasts
Richard Herrick, a professor from the College of the Holy Cross, visited Dartmouth to discuss his research in organometallic chemistry. He was recently named the O’Rourke Professor of Liberal Arts at Holy Cross for his research in the field of bioorganometallic chemistry, a relatively new branch of chemistry developed in the early 1990’s.
Herrick described the importance of bioorganometallic chemistry. He believed organometallic compounds could be used to answer biochemistry-related questions. He went on to discover a molecular structure, named “Herrick Conformation,” for organometallic compounds that could interact with protein structures. Bioorganometallic compounds exhibit unique structural and binding features, and have important uses in the health sector, such as for protein tagging and radio imaging.
For his most recent research, Herrick has been testing a variety of ligands on compounds containing rhenium. The underlying idea is that rhenium acts much like technetium, another element that is already used heavily in contrasting agents, and could potentially serve as a better alternative. An advantage of using rhenium instead of technetium is that the rhenium allows for better diffraction in certain media. Further, rhenium is not radioactive, unlike technetium. Herrick has already discovered a number of promising, stable rhenium-based compounds.
NEUROSCIENCE
Damage to the Postsubiculum Disrupts Fear Conditioning
David Bucci, Dartmouth professor of psychological and brain sciences, found the first evidence that suggests that the postsubiculum (PoSub) is involved in fear conditioning. PoSub is one of the parahippocampal structures that interfaces with the hippocampus in the brain. It is important for spatial learning and memory, but its influence on the formation of other types of associations, such as fear conditioning, was previously unknown. Bucci’s work is published in Hippocampus.
Bucci hypothesized that the PoSub lesions disrupt associative processes that link relevant external cues with internal cues involved in fear conditioning. To test their hypothesis, Bucci’s lab created PoSub lesions in test rats both before and after fear conditioning training. Pavlovian fear conditioning is a technique used to understand how learning occurs in response to various stimuli.
The Bucci lab quantified the animals’ fear response by measuring how often and for how long a rat exhibited “freezing” behavior, which is a natural behavioral response to aversive stimuli. The study tested the PoSub lesion’s effects on both contextual fear memory and auditory fear memory. Contextual fear memory is the conditioned fear in response to the training in the absence of the aversive stimulus, while auditory fear memory is the subject’s behavioral response to the tone that is associated with the fearful stimulus.
Contrary to the hypotheses of previous studies, the Bucci lab demonstrated that damage to the postsubiculum not only impairs the contextual and auditory fear response, but also impairs initial fear conditioning. They found that rats with the PoSub lesion exhibited significantly less freezing behavior than their control counterparts exhibited.
The study shows that the PoSub and the hippocampus have distinct roles in the retrieval of spatial information, which is crucial for contextual spatial learning. The study also demonstrates that PoSub lesions made after conditioning results in reduced expression and/or retrieval of auditory fear memory. Future studies would continue to investigate the functional contributions of the PoSub to fear learning and memory.