91AV

There are three ongoing research projects in Amy Deveau's (Dr. D) lab:

1. The design and synthesis of naltrexol derivatives for use as pain and addiction therapies
2. The synthesis and biological characterization of tryptophan-based DNA intercalators
3. The synthesis of medicinally active, nitrogen-containing compounds using green Suzuki Coupling methodology, and the extension of these experiments to the undergraduate organic lab curriculum.

Overall, Dr. D is passionate about finding ways to interest students in science and in learning new ways to integrate teaching and research in the classroom (i.e. chemical pedagogy).

Along with interested 91AV students and scholars, Stephen Fox, Ph.D., plans to:

• Continue to characterize the physical and structural properties of the dicopper(I) model and its derivatives
• Further customize the naphthyridine with electron-donating groups to enhance the reactivity of the dicopper(I) center; selectively remove/replace the bridging groups to investigate the utility of the dicopper(I) center as a catalyst for reactions such as aziridination
• Investigate factors influencing the metal-metal separation through theoretical computational studies.

Research in Amy Keirstead's (Dr. K) group covers a wide variety of traditional areas, from synthetic organic chemistry to photochemistry, spectroscopy, materials science, and green chemistry, and undergraduate students will gain experience in all of these areas. Two major pieces of equipment are used for this research: a photochemical reaction chamber, which is a steady-state instrument, and a nanosecond laser flash photolysis system, which uses a nanosecond laser and fast detection system to monitor reactions as they happen on the nanosecond to millisecond time scale.

Several areas of research are being explored in Jerome Mullin's, Ph.D., laboratory. One area is focused on the determination of heavy metal distributions in sediments from the Gulf of Maine, local rivers, and the Bering Sea, in an attempt to evaluate current levels of heavy metal pollution and identify degrees and sources of anthropogenic inputs of these elements. Of particular interest are the baseline heavy metal distributions in the Bering Sea, a relatively sparsely populated area of high primary productivity still considered to be largely unpolluted. Metals that have been determined to date, using atomic absorption spectroscopy and anodic stripping voltammetry, include cadmium, lead, and chromium.

Another area of research involves the spectroscopic and electrochemical characterization of a series of Group-14 and 15 metallacyclopentadienes (metalloles). These interesting compounds, which have unusual photoluminescence properties, show promise as monomeric units for the design of conducting polymers, for use in energy-transfer applications, as emitting species in light-emitting diodes (LEDs), and as components of chemical sensors. Luminescence quantum yields for the compounds recently have been determined and luminescence quenching studies are ongoing. Of special interest is the dramatic aggregation-induced emission (AIE) exhibited by many of these compounds, in which luminescence yields are increased by over two orders of magnitude compared to the unaggregated compounds. Current directions in this research also include the development of substituted metalloles designed for increased water solubility, improved luminescence yields, and for use as luminescent probes.

Photoluminescence is also the subject of research involving compounds containing a rare earth ion, e.g., Tb(III), Eu(III), or Dy(III) and the dicyanoaurate or dicyanoargentate ions. These compounds appear to have energy transfer characteristics that lead to "tunable" excitation of rare earth photoluminescence.

Other areas of interest include the development of fiber-optic probes based on fluorescence and/or chemiluminescence and the development of a chemiluminescence-based immunoassay system for the determination of trace amounts of dioxins.

Recent Grant Support: National Science Foundation, U.S. Fish and Wildlife Service, EOSAT Corporation, Pittsburgh Conference Memorial National Grants Program, American Chemical Society (ACS) Petroleum Research Fund (PRF), 91AV.

One major research area in Deena Small’s, Ph.D., laboratory is the investigation of how proteins belonging to the Jagged1/Notch and Fibroblast Growth Factor (FGF) families interact and regulate adipocyte differentiation in response to hormones such as insulin. Since adipose tissue development and function is also dependent on the ability of the mature fat cells to secure a vascular system that will support its metabolic requirements, the study also includes analysis of Jagged1/Notch and FGF interactions as a regulator of angiogenesis- the formation of new blood vessels from the existing vasculature.

The second research project in The Small Laboratory is a toxicology study that characterizes the effects that Polybrominated Diphenyl Ethers (PBDEs), chemicals used as flame retardants in a variety of household goods, have on mesenchymal stem cell differentiation. In particular, research is focused on analyzing the effects that these endocrine-disrupting chemicals have on mesenchymal stem cell growth dynamics and their ability to differentiate into adipocytes and osteoblasts. These studies also document the impact that early PBDE exposure has on the formation of adipose and bone. The ultimate goal of both projects is to understand the connection that these signaling mediators have on human health and disease. Both research projects use a combination of cell culture and in vivo biomedical models such as the mouse and zebrafish. Techniques include standard biochemical/molecular biology methods including quantitative RT-PCR, immunoblot, and ELISA. In addition, Dr. Small employs molecular techniques such as cloning to produce transgenic mice and zebrafish for the studies. These projects involve collaborations with scientists from 91AV, Maine Medical Center Research Institute, SUNY Geneseo, University of Maine, Bates College and University of Quebec, Montreal.

The first area of Jon Stubbs's research is focused on DNA sensor microarray technology, which is composed of single-stranded DNA oligomers bound to a surface. The development of this technology relies on knowledge of DNA denaturation or "melting" and hybridization transitions, and their sensitivity to many variables has left several questions unanswered, such as the mechanism by which changes in physical environment between solution and bound DNA act to influence hybridization, or competitive adsorption of nearly identical sequences.

The second area attempts to improve upon separation technology using fairly innocuous materials such as supercritical carbon dioxide and polyethylene glycol to achieve what traditional processes do with more detrimental materials. Molecular simulations allow the modeling of such systems with the goal of optimizing solvation conditions and is done by carrying out calculations with varying thermodynamic (e.g. temperature and/or pressure) conditions and compositions.

James Vesenka, Ph.D. (Dr. V) conducts research in the self-assembly process of four-stranded “G-wire” DNA using scanning probe microscopy (SPM). He is interested in understanding the kinetics of the self-assembly process and the interaction of the G-wire DNA with substrates and double-stranded DNA. G-wires make exciting candidates for possible nano-electronic devices, so he is interested in their electronic properties and the ability to manipulate the self-assembled structures at the microscopic level with the SPM. With the advent of fast local area networks he has safely connected the sensitive SPM to the noisy environment of the introductory physics lab using virtual network computing.

Dr. V also conducts research in the area of physics pedagogy. He is developing more effective means for teaching introductory physics through the use of multiple representation learning tools, also called “modeling,” which includes better student evaluation procedures. He has organized two workshops to train pre-service and in-service science teachers in Maine and California for the summer of 2000.

Grant support: Research Corporation, National Science Foundation, Maine Mathematics and Science Alliance.