Representative Publications

Mechanisms of Low-Power Noncoherent Photon Upconversion in Metalloporphyrin-Organic Blue Emitter Systems in Solution.
Sunish K. Sugunan et al. 2009.

The mechanisms of noncoherent photon upconversion that involve triplet-triplet annihilation (TTA) in solution have been investigated for two model systems. ZnTPP (meso-tetraphenylporphine zinc) is used as the model visible light-absorbing metalloporphyrin because its S1 fluorescence intensity can be used to monitor the initial rate of porphyrin triplet state production and because its S2 fluorescence intensity can be used as a direct measure of the rate of porphyrin TTA …

Solution structure of the N-domain of Wilson disease protein: Distinct nucleotide-binding environment and effects of disease mutations.
Oleg Demitriev et al. 2006.

Wilson disease protein (ATP7B) is a copper-transporting P1B-type ATPase that regulates copper homeostasis and biosynthesis of copper-containing enzymes in human tissues. Inactivation of ATP7B or related ATP7A leads to severe neurodegenerative disorders, whereas their overexpression contributes to cancer cell resistance to chemotherapeutics. Copper-transporting ATPases differ from other P-type ATPases in their topology and the sequence of their nucleotide-binding domain (N-domain). To gain insight into the structural basis of ATP7B function, we have solved the structure of the ATP7B N-domain in the presence of …

Single-Event Transients Effects on Dynamic Comparators in a 90nm CMOS Triple-Well and Dual-Well Technology.
Tao Wang et al. 2009

Single-Event Transient effects on dynamic comparators using dual-well and triple-well technologies in a 90-nm CMOS process are investigated using pulsed-laser and schematic simulations. Results show that circuit vulnerability is a strong function of technology, circuit topology, and individual transistor currents.

Understanding the Reactivity of Strained Sandwich Compounds with Aluminum or Gallium in Bridging Positions: Experiments and DFT Calculations.
Bidraha Bagh et al. 2012

The aluminum and gallium dichlorides (Mamx)ECl2 1a (E = Al; 82%) and 1b (E = Ga; 79%) (Mamx = 2,4-di-tert-butyl-6-[(dimethylamino)methyl]phenyl) reacted with dilithioferrocene or dilithioruthenocene to give [1]ferrocenophanes (2a, 2b) and [1]ruthenocenophanes (3a, 3b), respectively. The galla[1]ruthenocenophane 3b could be isolated from the reaction mixture through precipitation into hexane (50%), while 2a, 2b, and 3a underwent ring-opening polymerization under the reaction conditions of their formation reactions to give metallopolymers (Mw (DLS) between 8.07 and 106 kDa) …

The effect of pressure on .111. type iron arsenide superconductor.
S. J. Wang et al. 2009

Resistance measurements of a "111" type superconductor LixFeAs (x=0.8,1.0,1.1) were performed at high pressure. The superconductivity transition temperature (Tc) is found to decrease almost linearly with increasing pressure and the pressure derivative, dTc/dP, becomes smaller with increasing Li content. Electron spin resonance experiment at ambient pressure on a stoichometric sample shows gradual decrease in the spin moment and the loss of coherence of spin coupling as the temperature is lowered. A very weak Fe local moment is observed when the temperature is lowered to Tc. In situ synchrotron radiation powder x-ray diffraction at high pressure shows changes in the resistivity are not related to a structural transition …

Iron pairs in beryl: New insights from electron paramagnetic resonance, synchrotron X-ray absorption spectroscopy, and ab initio calculations.
Jinru Lin et al. 2013

Berylís various coloring make it a sought-after and precious gemstone. Knowledge on the physical origin behind the various colorings is essential to differentiate artificial colorings from natural ones. The blue color of the variety aquamarine has been proposed to be due to charge transfer between adjacent Fe3+-Fe2+ pairs on the Al site and its adjacent 6g interstitial position, respectively. The present work presents the first experimental confirmation of such an arrangement …

Discovery of inhibitors and substrates of brassinin hydrolase: Probing selectivity with dithiocarbamate bioisosteres.
M. Soledade Pedras et al. 2012

Brassinin hydrolase (BHAb), an inducible enzyme produced by the plant pathogen Alternaria brassicicola under stress conditions, catalyzes the hydrolysis of the methyl dithiocarbamate group of the phytoalexin brassinin, to indolyl-3-methanamine, methane thiol and carbonyl sulfide. Thirty four substrate inspired compounds, bioisosteres of brassinin and a range of related compounds, were evaluated as potential substrates and inhibitors of BHAb for the first time. While six compounds containing thiocarbamate, carbamate and carbonate groups displayed inhibitory activity against BHAb, only two were found to be substrates (thionecarbamate and dithiocarbamate). Methyl naphthalen-1-yl-methyl carbamate, the most potent inhibitor of the six, and methyl N'-(1-methyl-3-indolylmethyl)carbamate inhibited BHAb through a reversible noncompetitive mechanism (Ki = 89 ± 9 and 695 ± 60 μM, respectively) …

Phosphorus speciation in riparian soils: A phosphorus-31 nuclear magnetic resonance spectroscopy and enzyme hydrolysis study.
Eric O. Young et al. 2012

In the Lake Champlain Basin, phosphorus (P) loading from streambank erosion and cropland are both important P sources, and a better understanding of the factors affecting riparian P loss is needed to help prioritize riparian restoration efforts. We utilized solution phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy and an enzyme hydrolysis method to characterize P and assess bioavailability in 14 commonly mapped riparian soils from northwestern Vermont. Surface horizons were sampled from distinct series at two riparian restoration sites to capture a range of soil properties …