The Ohio Journal of - The Ohio Academy of Science

Vol. 112(1)
1:30 PM
Undergraduate Research Session
Dr. Jeffrey D. Weidenhamer, Presiding
Kettering Science Center Lecture Hall Room 112
1:30 Introduction—Dr. Jeffrey D. Weidenhamer—See page 5.
1:40 MENTORING UNDERGRADUATES FOR SUCCESS IN
RESEARCH. S. Tonia Hsieh, sthsieh@temple.edu, Department
of Biology, 1900 North 12th St, Temple University,
Philadelphia, PA 19122.
Undergraduate research and inquiry-based learning are
two tools critical for inspiring our future generations
of scientists and leaders. While these methods for
engaging students are well-known and often-practiced at
predominately undergraduate institutions, exploring new
methods for teaching and prioritization of undergraduate
research at more research-focused institutions are often
overlooked. Primary reasons cited for not involving
undergraduates in research include principal investigators
lacking the time to work with undergraduates due to
already over-burdened schedules, the lack of preparation
amongst the student body for critical thinking skills
necessary for research, and the (supposed) inability
of undergraduates to produce “useful” research. Such
misperceptions are a travesty for scientific progress and
a disservice to an undergraduate population that is filled
with creative, knowledge-hungry students who can play a
critical role driving innovation in even the busiest research
lab. When properly conceived and supported by the right
strategies, undergraduate research can be mentored by a
“time-taxed” assistant professor at a research university
and lead to undergraduates presenting talks at national
meetings and co-authoring peer-reviewed publications.
2:30 LEAD AND CADMIUM IN CONSUMER PRODUCTS:
UNDERGRADUATE RESEARCH AT ASHLAND UNIVERSITY
IMPACTING PUBLIC POLICY. Jeffrey D. Weidenhamer,
jweiden@ashland.edu, Department of Chemistry, Geology
& Physics, 401 College Ave, Ashland University, Ashland, OH
44805.
Following the death of a 4-year-old Minnesota boy after
swallowing a highly leaded bracelet charm, the lead
content of children’s jewelry from local dollar stores was
investigated in a course for non-science majors on lead’s
chemistry and toxicity. This blossomed into an ongoing
research effort that has involved science majors in Ashland
University’s analytical chemistry courses and independent
research projects. Jewelry samples and painted toys were
screened for heavy metal content by X-ray fluorescence
(XRF), and lead and cadmium content determined by acid
digestion followed by atomic absorption analysis. Lead and
cadmium bioavailability from jewelry has been determined
using saline extractions to simulate exposure by mouthing
of jewelry and dilute HCl extractions to simulate the worstcase
scenario of ingestion of a jewelry item. Most recently,
cadmium bioavailability was evaluated in 86 components
of 57 jewelry items found to contain high levels of cadmium
(> 10,000 ppm) by XRF. Saline extraction yielded as much
as 2,200 µg cadmium, and 24-hr dilute HCl extraction
yielded a maximum of > 20,000 µg cadmium. These
amounts exceed the maximum amounts recommended by
the United States Consumer Product Safety Commission
(CPSC) by a factor of 100, indicating the potential for
dangerous exposures to children who mouth or swallow
this jewelry. The undergraduate research projects have
resulted in eight peer-reviewed publications (including
four papers co-authored by six different undergraduates),
and more than a dozen CPSC recalls of jewelry and toys
with high lead content as well as the first CPSC recalls of
consumer products for cadmium contamination.
The Ohio Journal of Science A-51
2:45 UNDERGRADUATE RESEARCH IN POLYMER CHEMISTRY
AT ASHLAND UNIVERSITY: POLYLACTIDE/POLYETHYLENE
GLYCOL STAR BLOCK COPOLYMERS. Perry S. Corbin, pcorbin@
ashland.edu, Ashland University, Department of Chemistry/
Geology/Physics, 401 College Ave., Ashland, OH 44805.
The synthesis of polymers that have varied molecular
architectures and are designed to self-organize into higherorder
structures is critical to the continued development
of multifaceted materials. The preparation of such
polymers has been the goal of a long-term undergraduate
research program at Ashland University. Studies have
recently focused on novel four-armed, calixarene- and
resorcinarene-core polylactide (PLA)/polyethylene glycol
(PEG) star block copolymers. These polymers may function
as useful drug-delivery vehicles upon assembling into
aqueous micelles. To synthesize the block copolymers,
PLA star homopolymers were first prepared by tin(II)catalyzed
ring-opening polymerizations of L-lactide. To
couple PEG with the PLA chains, the homopolymer end
groups were activated, and, subsequently, reacted with a
nucleophilic, amino-PEG. The PLA-PEGs were purified by
dialysis and multiple water washes. The disappearance
of the signal for the terminal methine hydrogens of the
PLA chain ends in nuclear magnetic resonance ( 1 H-NMR)
spectra of the activated PLA homopolymers suggested
that the activation proceeded to completion. 1 H-NMR
spectral integrations also allowed the degree of PLA-
PEG coupling to be estimated in the second step of the
convergent synthesis. Coupling efficiencies were estimated
to be high (>90%). Further fluorescence spectroscopic and
light-scattering studies indicated that aqueous micelles,
indeed, form from the calixarene- and resorcinarenecore
star block copolymers. In addition to the scientific
merit of such studies, undergraduates obtain invaluable
research training, develop reasoning skills, and examine
important aspects of polymer chemistry—an area that,
in some instances, does not receive its due attention in
undergraduate chemistry curricula.
3:00 FROM PROTEINS TO POLYLACTIDES: APPLICATION
OF MALDI MASS SPECTROMETRY TO UNDERGRADUATE
RESEARCH AT ASHLAND UNIVERSITY. Rebecca W. Corbin,
rcorbin@ashland.edu, Ashland University, Department of
Chemistry/Geology/Physics, 401 College Avenue, Ashland
OH 44805.
Matrix-assisted laser desorption/ionization (MALDI)
with time-of-flight mass spectrometry (TOF MS) is one
of the most versatile methods for the characterization
of biological as well as synthetic polymer samples.
MALDI-TOF MS serves an important role in a variety of
interdisciplinary research projects at Ashland University.
Over twelve undergraduates have been involved with
these collaborations. Students learn to prepare samples,
to evaluate matrix-analyte formulations, to optimize
instrumental parameters, and to determine appropriate
data analysis strategies for collaborative projects involving
proteomics as well as polymer synthesis. One proteomics
project involves MALDI-TOF MS analysis of recombinant
and purified eye lens crystallins from the zebrafish Danio
rerio. Results indicate the identity of specific crystallin
sequences and suggest the presence of structurally
modified forms. A second research project is the
identification of circadian clock-associated proteins in the
filamentous fungus Aspergillus nidulans. Comparing twodimensional
gel electrophoresis profiles of proteins isolated
at different time points allows the targeting of candidates
associated with an internal circadian oscillator. One such
protein, glyceraldehyde-3-phosphate dehydrogenase,
has been identified by tryptic digestion of an excised gel
spot followed by MALDI mass fingerprinting. The longterm
goal of an additional proteomics collaboration is the
identification of neuronal interleukin-16 binding partners.
MALDI-TOF MS also proves to be effective for the
characterization of synthetic polymers. Specifically, the
acquisition of mass spectra from polylactide star polymers
provides information that is complementary to molecular