This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. To further enhance our instrumentation capability in pulsed ESR microscopy, where unlike c.w., the experimenter can directly measure many key parameters such as self diffusion, relaxation times of the magnetic probe, viscosity, accurate O2 concentration, etc., we have designed a programmable pulsed field gradient coil driver of advanced capability. Based on a hybrid topology consisting of our existing gated-haversine coil excitation scheme and a fast-switched constant-current source, the new gradient coil driver design can be operated in either a prgrammable """"""""rectangular"""""""" mode to accommodate our need for time-invariant gradients during the pulse sequence, or the previous fast """"""""haversine"""""""" gradient excitation mode. The main advantage of a fast pulsed rectangular gradient is that it can be turned on, for example, only during each imaging pulse sequence, which enables the operator to avoid the problem of a heat producing constant gradient in one of the dimensions for frequency-encoded imaging applications. Ultimately, with further development, we expect to be able to produce short rectangular gradient pulses of ca 100ns at 0.5% stability. Such gradients can be selectively turned on during a specific microwave pulse which would permit, e.g., the possibility for slice selection imaging capability. Furthermore, when operating in the mode of our present haversine current driver, the new hybrid design would be capable of stronger and shorter pulsed field gradients which are necessary to support ESRM studies of nitroxide radicals with T2's in the 100 ?400ns range. After the planned developments and improvements in the gradient drivers, it is anticipated that the imaging probes will be able to generate haversine pulsed field gradients with durations of ~80 ns. A two-channel prototype """"""""hybrid"""""""" pulsed field gradient coil driver has been designed and constructed and is presently under test. During the coming year, this unit will replace the existing haversine-only coil driver system, and continuing developmental upgrades will be incorporated and evaluated in situ.

National Institute of Health (NIH)
National Center for Research Resources (NCRR)
Biotechnology Resource Grants (P41)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-BCMB-K (40))
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Cornell University
Schools of Arts and Sciences
United States
Zip Code
Jain, Rinku; Vanamee, Eva S; Dzikovski, Boris G et al. (2014) An iron-sulfur cluster in the polymerase domain of yeast DNA polymerase ?. J Mol Biol 426:301-8
Pratt, Ashley J; Shin, David S; Merz, Gregory E et al. (2014) Aggregation propensities of superoxide dismutase G93 hotspot mutants mirror ALS clinical phenotypes. Proc Natl Acad Sci U S A 111:E4568-76
Georgieva, Elka R; Borbat, Peter P; Ginter, Christopher et al. (2013) Conformational ensemble of the sodium-coupled aspartate transporter. Nat Struct Mol Biol 20:215-21
Airola, Michael V; Sukomon, Nattakan; Samanta, Dipanjan et al. (2013) HAMP domain conformers that propagate opposite signals in bacterial chemoreceptors. PLoS Biol 11:e1001479
Airola, Michael V; Huh, Doowon; Sukomon, Nattakan et al. (2013) Architecture of the soluble receptor Aer2 indicates an in-line mechanism for PAS and HAMP domain signaling. J Mol Biol 425:886-901
Sun, Yan; Zhang, Ziwei; Grigoryants, Vladimir M et al. (2012) The internal dynamics of mini c TAR DNA probed by electron paramagnetic resonance of nitroxide spin-labels at the lower stem, the loop, and the bulge. Biochemistry 51:8530-41
Smith, Andrew K; Freed, Jack H (2012) Dynamics and ordering of lipid spin-labels along the coexistence curve of two membrane phases: an ESR study. Chem Phys Lipids 165:348-61
Yu, Renyuan Pony; Darmon, Jonathan M; Hoyt, Jordan M et al. (2012) High-Activity Iron Catalysts for the Hydrogenation of Hindered, Unfunctionalized Alkenes. ACS Catal 2:1760-1764
Gaffney, Betty J; Bradshaw, Miles D; Frausto, Stephen D et al. (2012) Locating a lipid at the portal to the lipoxygenase active site. Biophys J 103:2134-44
Dzikovski, Boris; Tipikin, Dmitriy; Freed, Jack (2012) Conformational distributions and hydrogen bonding in gel and frozen lipid bilayers: a high frequency spin-label ESR study. J Phys Chem B 116:6694-706

Showing the most recent 10 out of 72 publications