Scientific Publications 2001
2001. "Multiscale Modeling and Simulation Methods with Applications to Dentritic Polymers." Computational and Theoretical Polymer Science 11(5):345-356. Abstract Dendrimers and hyperbranched polymers represent a novel class of structurally controlled macromolecules derived from a branches-upon-branches structural motif. The synthetic procedures developed for dendrimer preparation permit nearly complete control over the critical molecular design parameter, such as size, shape, surface/interior chemistry, flexibility, and topology. Dendrimers are well defined, highly branched macromolecules that radiate from a central core and are synthesized through a stepwise, repetetive reaction sequence that guarantees complete shells for each generation, leading to polymers that are mono-disperse.
2001. "Computers for Integrative Instruction in Bioengineering Labs." Computing in Science & Engineering 3(5):73-83. Abstract The advent of ubiquitous computing technology has transformed scientific and engineering research and development work in less than one generation. The other focus articles in this issue describe how this transformation is manifested in bioengineering and biophysics practices. A natural question is, “What, if any, implications does this have for undergraduate education in these fields?” In this article, we provide two case studies—one from the University of Pennsylvania and another from Columbia University—that illustrate our attempts to transform the educational process based on changes in professional practice.
2001. "Coherent Raman and Infrared Studies of Sulfur Trioxide." Journal of Molecular Spectroscopy 210:233-239. Abstract High resolution (0.001 cm-1) coherent anti-Stokes Raman scattering (CARS) was used to observe the Q-branch structure of the IR-inactive n1 symmetric stretching mode of 32S 16O3 and its various 18O isotopomers. The v1 spectrum of 32S 16O3 reveals two intense Q-branch regions in the 1065-1067 cm-1 region, with surprisingly complex vibrational-rotational structure not resolved in earlier studies. Efforts to simulate this with a simple Fermi-resonance model involving v1 and 2v4 do not reproduce the spectral detail nor yield reasonable spectroscopic parameters. A more subtle combination of Fermi resonance and indirect Coriolis interactions with nearby states; 2v4 (l = 0, ? 2), v2+v4 (l = ? 1), 2v2 (l =0) is suspected and a determination of the location of these coupled states by high resolution infrared measurements is underway. At medium resolution (0.125 cm-1), the infrared spectra reveal Q-branch features from which approximate band origins are estimated for the v2, v3, v4 fundamental modes of 32S 18O3, 32S 18O2 16O and 32S 18O 16O2. These and literature data for 32S 16O3 are used to calculate force constants for SO3 and a comparison is made with similar values for SO2 and SO. The frequencies and force constants are in excellent agreement with a recent ab initio calculation by Martin. *In memory of Dr. Nicolae Vulpanovici (1968-2001)
2001. "NMR Structure Determination and Structure-Based Functional Characterization of a Conserved, Hypothetical Protein MTH1175 from Methanobacterium thermoautotrophicum." Journal of Structural and Functional Genomics 1:15-25. Abstract The solution structure of MTH1175, a 124-residue protein from the archaecon Methanobacterium thermoautotrophicum has been determined by NMR spectroscopy.
2001. "Solution Structure of Pyrobaculum aerophilum DsrC, an Archaeal Homologue of the Gamma Subunit of Dissimilatory Sulfite Reductase." European Journal of Biochemistry / FEBS 268(22):5842-50. Abstract The solution structure of DsrC, an archaeal homologue of the g subunit of dissimilatory sulfite reductase has been determined by NMR spectroscopy. This 12.7 kDa protein from the hyperthermophilic archaeon Pyrobaculum aerophilum adopts a novel fold consisting of an orthogonal helical bundle with a b-hairpin along one side. A portion of the structure resembles the helix-turn-helix DNA-binding motif common in transcriptional regulator proteins. The protein contains two disulfide bonds but remains folded in the presence of DTT. DsrC proteins from organisms other than Pyrobaculum species do not contain these disulfide bonds. A conserved cysteine next to the C-terminus, which is not involved in the disulfide bonds, is not part of the globular structure of the protein and is located on an unstructured 7-residue C-terminal arm that extends away from the center of the protein.