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2015

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Articles 2461 - 2490 of 12617

Full-Text Articles in Physical Sciences and Mathematics

Dielectric Behavior Of 95.5% Pb(Zn1/3nb2/3)O-3-4.5% Pbtio3 Single Crystals Under Dc Bias From 12-550 K, Ang Chen, Zhi Yu Sep 2015

Dielectric Behavior Of 95.5% Pb(Zn1/3nb2/3)O-3-4.5% Pbtio3 Single Crystals Under Dc Bias From 12-550 K, Ang Chen, Zhi Yu

Ang Chen

This work reports a detailed study of the dielectric behavior of 95.5% Pb(Zn1/3Nb2/3)O-3 - 4.5% PbTiO3 (PZN-4.5PT) single crystals with and without dc bias. It is found that there are at least five sets of dielectric anomalies for PZN-4.5PT from 12K to 550K. There are two dielectric peaks, around 430K and 395K, which are referred to as cubic-tetragonal and tetragonal- rhombohedral phase transitions, respectively, above room temperature. Furthermore, a set of broad peaks around 350K (at 10kHz) that showed up under electric field of 10kV/cm might indicate the existence of a monoclinic distortion M-A phase.

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Adhesion And Friction Characteristics Of Carbon Nanotube Arrays, Alper Buldum Sep 2015

Adhesion And Friction Characteristics Of Carbon Nanotube Arrays, Alper Buldum

Alper Buldum

There has been a great deal of interest in understanding, design and fabrication of bio-mimetic and bio-inspired adhesives in recent years. In this paper we present theoretical investigations on adhesion, friction behaviors and characteristics of fibrillar arrays composed of noninteracting carbon nanotubes for bio-inspired dry adhesives. Contact, compression, subsequent pulling off and dry sliding friction simulations were performed. It is demonstrated that there are two different adhesion forces during pull off. Static friction force values are in between 40 and 60 N cm(-2) at different loads and they are significantly larger than the normal adhesion forces. Dynamic friction force and …

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Pentacene-Fused Diporphyrins, Lin Jiang, James Engle, Ross Zaenglein, Alex Matus, Christopher Ziegler, Hong Wang, Martin Stillman Sep 2015

Pentacene-Fused Diporphyrins, Lin Jiang, James Engle, Ross Zaenglein, Alex Matus, Christopher Ziegler, Hong Wang, Martin Stillman

Christopher J. Ziegler

In this work, we report the synthesis, spectroscopic characterization, and theoretical analysis of a linearly conjugated pentacene-fused porphyrin dimer and cross-conjugated quinone-fused dinaphtho[2,3]porphyrins. These multichromophoric systems display non-typical UV-visible absorptions of either porphyrins or pentacenes/quinones. UV-visible, emission and magnetic circular dichroism (MCD) spectroscopy suggest strong electronic interactions among the multichromophores in the system. DFT calculations revealed the delocalization of the HOMOs and LUMOs spanning the entire dimer and linker assembly. The pentacene-fused porphyrin dimer is significantly more stable than both the corresponding pentacene and the heptacene derivatives. The availability of these huge π-extended and electronically highly interactive multichromophoric systems promises …

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Combined Mcd/Dft/Tddft Study Of The Electronic Structure Of Axially Pyridine Coordinated Metallocorroles, Hannah Rhoda, Laura Crandall, G. Geier, Christopher Ziegler, Victor Nemykin Sep 2015

Combined Mcd/Dft/Tddft Study Of The Electronic Structure Of Axially Pyridine Coordinated Metallocorroles, Hannah Rhoda, Laura Crandall, G. Geier, Christopher Ziegler, Victor Nemykin

Christopher J. Ziegler

A series of metallocorroles were investigated by UV−vis and MCD spectroscopies to investigate similarities and differences in the electronic structure and spectroscopy of the closed- and open-shell metallocorroles. Similar to the free-base H3tpfc, inspection of the MCD Faraday B-terms for all of the macrocycles presented here revealed that a ΔHOMO < ΔLUMO condition is present for each complex, which results in an unusual sign-reversed sequence for π−π* transitions in their MCD spectra.

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Synthesis Of Dimeric Rhenium Phenylenediimine Conjugates, Christopher Ziegler, J Bass, C Bogdanowicz, R Herrick, A Hasheminasab Sep 2015

Synthesis Of Dimeric Rhenium Phenylenediimine Conjugates, Christopher Ziegler, J Bass, C Bogdanowicz, R Herrick, A Hasheminasab

Christopher J. Ziegler

No abstract provided.

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Improved Synthesis Of [Re(Co)(3)(H2o)(3)]Br And Its Derivatives, Gerard Kerins, Joshua Farrell, Richard Herrick, Christopher Ziegler Sep 2015

Improved Synthesis Of [Re(Co)(3)(H2o)(3)]Br And Its Derivatives, Gerard Kerins, Joshua Farrell, Richard Herrick, Christopher Ziegler

Christopher J. Ziegler

Rhenium has been studied at length as a non-radioactive chemical analog to Technetium, a popular diagnostic imaging agent employed in nuclear medicine and biology. This study details a new synthetic method for preparing [Re(CO)3(H2O)3]Br as well as multiple derivatives of this complex using tridentate ligands. Full synthetic details and characterization will be pre

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Enhanced Helical Folding Of Ortho-Phenylenes Through The Control Of Aromatic Stacking Interactions, Sanyo Mathew, Laura Crandall, Christopher Ziegler Sep 2015

Enhanced Helical Folding Of Ortho-Phenylenes Through The Control Of Aromatic Stacking Interactions, Sanyo Mathew, Laura Crandall, Christopher Ziegler

Christopher J. Ziegler

The ortho-phenylenes are a simple class of foldamers, with the formation of helices driven by offset aromatic stacking interactions parallel to the helical axis. For the majority of reported o-phenylene oligomers, the perfectly folded conformer comprises perhaps 50–75% of the total population. Given the hundreds or thousands of possible conformers for even short oligomers, this distribution represents a substantial bias toward the folded state. However, “next-generation” o-phenylenes with better folding properties are needed if these structures are to be exploited as functional units within more complex architectures. Here, we report several new series of o-phenylene oligomers, varying both the nature …

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Structure And Conformation Of The Medium-Sized Chlorophosphazene Rings, Bowers, David Bowers, Brian Wright, Vincenzo Scionti, Anthony Schultz, Matthew Panzner, Eric Twum, Lin-Lin Li, Bryan Katzenmeyer, Benjamin Thome, Peter Rinaldi, Chrys Wesdemiotis, Wiley Youngs, Claire Tessier Sep 2015

Structure And Conformation Of The Medium-Sized Chlorophosphazene Rings, Bowers, David Bowers, Brian Wright, Vincenzo Scionti, Anthony Schultz, Matthew Panzner, Eric Twum, Lin-Lin Li, Bryan Katzenmeyer, Benjamin Thome, Peter Rinaldi, Chrys Wesdemiotis, Wiley Youngs, Claire Tessier

Wiley J. Youngs

No abstract provided.

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Structure And Conformation Of Meso-2,4-Di(N-Carbazolyl)Pentane, Patrick Wagers, Wiley Youngs, Aditya Agrahari, Steven Schildcrout, John Masnovi Sep 2015

Structure And Conformation Of Meso-2,4-Di(N-Carbazolyl)Pentane, Patrick Wagers, Wiley Youngs, Aditya Agrahari, Steven Schildcrout, John Masnovi

Wiley J. Youngs

The stereochemistry of the title compound is established as meso. The carbazole groups have no parallel planar close contacts (π-type interactions), which differs from the packing found previously for terminal 1,n-di(N-carbazolyl)alkanes. Bond distances, bond angles, and torsion angles are compared with those calculated for the isolated molecule using M06-2X density functional theory, which is designed to model intramolecular dispersion effects. The results indicate that dispersion effects have a significant influence on the molecular conformation, although packing effects likely determine the magnitude of the puckering about one of the nitrogens (N1) and give a crystal conformation …

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Investigating The Pharmacokinetics And Biological Distribution Of Silver-Loaded Polyphosphoester-Based Nanoparticles Using 111ag As A Radiotracer, Tolulope Aweda, Shiyi Zhang, Chiedza Mupanomunda, Jennifer Burkemper, Gyu Heo, Nilantha Bandara, Mai Lin, Cathy Cutler, Carolyn Cannon, Wiley Youngs, Karen Wooley, Suzanne Lapi Sep 2015

Investigating The Pharmacokinetics And Biological Distribution Of Silver-Loaded Polyphosphoester-Based Nanoparticles Using 111ag As A Radiotracer, Tolulope Aweda, Shiyi Zhang, Chiedza Mupanomunda, Jennifer Burkemper, Gyu Heo, Nilantha Bandara, Mai Lin, Cathy Cutler, Carolyn Cannon, Wiley Youngs, Karen Wooley, Suzanne Lapi

Wiley J. Youngs

Purified 111Ag was used as a radiotracer to investigate silver loading and release, pharmacokinetics, and biodistribution of polyphosphoester-based degradable shell crosslinked knedel-like (SCK) nanoparticles as a comparison to the previously reported small molecule, N-heterocyclic silver carbene complex analog (SCC1) for the delivery of therapeutic silver ions in mouse models. Biodistribution studies were conducted by aerosol administration of 111Ag acetate, [111Ag]SCC1, and [111Ag]SCK doses directly into the lungs of C57BL/6 mice. Nebulization of the 111Ag antimicrobials resulted in an average uptake of 1.07 ± 0.12% of the total aerosolized dose given per mouse. The average dose taken into the lungs of …

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Preparation And In Vitro Antimicrobial Activity Of Silver-Bearing Degradable Polymeric Nanoparticles Of Polyphosphoester-Block-Poly(L-Lactide), Young Lim, Kristin Tiemann, Gyu Heo, Patrick Wager, Yohannes Rezenom, Shiyi Zhang, Fuwu Zhang, Wiley Youngs, David Hunstad, Karen Wooley Sep 2015

Preparation And In Vitro Antimicrobial Activity Of Silver-Bearing Degradable Polymeric Nanoparticles Of Polyphosphoester-Block-Poly(L-Lactide), Young Lim, Kristin Tiemann, Gyu Heo, Patrick Wager, Yohannes Rezenom, Shiyi Zhang, Fuwu Zhang, Wiley Youngs, David Hunstad, Karen Wooley

Wiley J. Youngs

The development of well-defined polymeric nanoparticles (NPs) as delivery carriers for antimicrobials targeting human infectious diseases requires rational design of the polymer template, an efficient synthetic approach, and fundamental understanding of the developed NPs, e.g., drug loading/release, particle stability, and other characteristics. Herein, we developed and evaluated the in vitro antimicrobial activity of silver-bearing, fully biodegradable and functional polymeric NPs. A series of degradable polymeric nanoparticles (dNPs), composed of phosphoester and l-lactide and designed specifically for silver loading into the hydrophilic shell and/or the hydrophobic core, were prepared as potential delivery carriers for three different types of silver-based antimicrobials–silver acetate …

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Structure And Conformation Of The Medium-Sized Chlorophosphazene Rings, Bowers, David Bowers, Brian Wright, Vincenzo Scionti, Anthony Schultz, Matthew Panzner, Eric Twum, Lin-Lin Li, Bryan Katzenmeyer, Benjamin Thome, Peter Rinaldi, Chrys Wesdemiotis, Wiley Youngs, Claire Tessier Sep 2015

Structure And Conformation Of The Medium-Sized Chlorophosphazene Rings, Bowers, David Bowers, Brian Wright, Vincenzo Scionti, Anthony Schultz, Matthew Panzner, Eric Twum, Lin-Lin Li, Bryan Katzenmeyer, Benjamin Thome, Peter Rinaldi, Chrys Wesdemiotis, Wiley Youngs, Claire Tessier

Claire A. Tessier

No abstract provided.

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Tuning The Mobility Coupling Of Quaternized Polyvinylpyridine And Anionic Phospholipids In Supported Lipid Bilayers, Xiaojun Shi, Xiaosi Li, Megan Kaliszewski, Xiaodong Zhuang, Adam Smith Sep 2015

Tuning The Mobility Coupling Of Quaternized Polyvinylpyridine And Anionic Phospholipids In Supported Lipid Bilayers, Xiaojun Shi, Xiaosi Li, Megan Kaliszewski, Xiaodong Zhuang, Adam Smith

Adam W. Smith

Binding of biomacromolecules to anionic lipids in the plasma membrane is a common motif in many cell signaling pathways. Previous work has shown that macromolecules with cationic sequences can form nanodomains with sequestered anionic lipids, which alters the lateral distribution and mobility of the membrane lipids. Such sequestration is believed to result from the formation of a lipid–macromolecule complex. To date, however, the molecular structure and dynamics of the lipid–polymer interface are poorly understood. We have investigated the behavior of polycationic quaternized polyvinylpyridine (QPVP) on supported lipid bilayers doped with phosphatidylserine (PS) or phosphatidylinositol phosphate (PIP) lipids using time-resolved fluorescence …

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Contrasting Patterns Of Coupling Between The Ch Stretches And The Large-Amplitude Motions In The Molecules, Ch3nh2, Ch3oh2+ And Ch3ch2radical Dot, Mahesh Dawadi, Ram Bhatta, David Perry Sep 2015

Contrasting Patterns Of Coupling Between The Ch Stretches And The Large-Amplitude Motions In The Molecules, Ch3nh2, Ch3oh2+ And Ch3ch2radical Dot, Mahesh Dawadi, Ram Bhatta, David Perry

David S. Perry

In each of the title molecules, torsional and inversion tunneling occurs between six equivalent minima. The coupling between these large-amplitude motions and the CH stretch vibrations stems from the variation of the CH stretching force constants as a function of the torsional and inversion coordinates. First principles 2D maps of the variation of the CH-stretch force constants are reported. Although the torsional barriers differ by more than a factor of 20, the torsion–inversion–vibration coupling is similar for two of the species, CH3NH2 and CH3CH2, but is much weaker and qualitatively different in form …

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Inflammation Triggers Production Of Dimethylsphingosine From Oligodendrocytes, Leah Shriver, Alexandra Taraboletti, S Hill, Y Chen, H Huang, K Cho, R Gallo, M Manchester, G Patti Sep 2015

Inflammation Triggers Production Of Dimethylsphingosine From Oligodendrocytes, Leah Shriver, Alexandra Taraboletti, S Hill, Y Chen, H Huang, K Cho, R Gallo, M Manchester, G Patti

Leah Shriver

Neuropathic pain is a chronic, refractory condition that arises after damage to the nervous system. We previously showed that an increased level of the endogenous metabolite N,N-dimethylsphingosine (DMS) in the central nervous system (CNS) is sufficient to induce neuropathic pain-like behavior in rats. However, several important questions remain. First, it has not yet been demonstrated that DMS is produced in humans and its value as a therapeutic target is therefore unknown. Second, the cell types within the CNS that produce DMS are currently unidentified. Here we provide evidence that DMS is present in human CNS tissue. We show that DMS …

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Unexpected Synthesis Of 1,3,5-Triarly-1,5-Diketones From Aryl Ketones Via Di-Enamine Mechanism, Bin Liu, Junfeng Wang, Yi Pang, Zemei Ge, Runtao Li Sep 2015

Unexpected Synthesis Of 1,3,5-Triarly-1,5-Diketones From Aryl Ketones Via Di-Enamine Mechanism, Bin Liu, Junfeng Wang, Yi Pang, Zemei Ge, Runtao Li

Yi Pang

An unexpected reaction of aryl ketone with acetohydrazone of aromatic aldehyde via 1,2-di-enamine/diiminium mechanism was discovered, leading to efficient synthesis of 1,3,5-triaryl-1,5-diketones in good to excellent yields. (C) 2014 Elsevier Ltd. All rights reserved.

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Biocompatible Flavone-Based Fluorogenic Probes For Quick Wash-Free Mitochondria! Imaging In Living Cells, Bin Liu, Mickey Shah, Ge Zhang, Qin Liu, Yi Pang Sep 2015

Biocompatible Flavone-Based Fluorogenic Probes For Quick Wash-Free Mitochondria! Imaging In Living Cells, Bin Liu, Mickey Shah, Ge Zhang, Qin Liu, Yi Pang

Yi Pang

Mitochondria, vital organelles existing in almost all eukaryotic cells, play a crucial role in energy metabolism and apoptosis of aerobic organisms. In this work, we report two new flavone-based fluorescent probes, MC-Mito1 and MC-Mito2, for monitoring mitochondria in living cells. These two probes exhibit remarkably low toxicity, good cell permeability, and high specificity; these probes complement the existing library of mitochondrial imaging agents. The new dyes give nearly no background fluorescence, and their application does not require tedious postwashing after cell staining. The appreciable tolerance of MC-Mito2 encourages a broader range of biological applications for understanding the cell degeneration and …

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A Single Molecular Probe For Multi-Analyte (Cr3+, Al3+ And Fe3+) Detection In Aqueous Medium And Its Biological Application, Junfeng Wang, Yingbo Li, Nikul Patel, Ge Zhang, Demin Zhou, Yi Pang Sep 2015

A Single Molecular Probe For Multi-Analyte (Cr3+, Al3+ And Fe3+) Detection In Aqueous Medium And Its Biological Application, Junfeng Wang, Yingbo Li, Nikul Patel, Ge Zhang, Demin Zhou, Yi Pang

Yi Pang

An ESIPT based fluorescent sensor 1 was developed, which could selectively detect and differentiate trivalent metal ions Cr3+, Al3+ and Fe3+ in aqueous medium. The cell imaging experiments confirmed that 1 can be used for monitoring intracellular Cr3+ and Al3+ levels in living cells.

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L.A. River Project, Erin Payne Sep 2015

L.A. River Project, Erin Payne

The STEAM Journal

A field note that reflected the artists' experience of the city and the making of art through an activity at the L.A. River.

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Embアルゴリズムの新たな応用による多重比率補定(高橋将宜), Masayoshi Takahashi Sep 2015

Embアルゴリズムの新たな応用による多重比率補定(高橋将宜), Masayoshi Takahashi

Masayoshi Takahashi

No abstract provided.

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Is Atmospheric Phosphorus Pollution Altering Global Alpine Lake Stoichiometry?, Janice Brahney, Natalie Mahowald, Daniel S. Ward, Ashley P. Ballantyne, Jason C. Neff Sep 2015

Is Atmospheric Phosphorus Pollution Altering Global Alpine Lake Stoichiometry?, Janice Brahney, Natalie Mahowald, Daniel S. Ward, Ashley P. Ballantyne, Jason C. Neff

Ecosystem and Conservation Sciences Faculty Publications

Anthropogenic activities have significantly altered atmospheric chemistry and changed the global mobility of key macro-nutrients. Here we show that contemporary global patterns in nitrogen (N) and phosphorus (P) emissions drive large hemispheric variation in precipitation chemistry. These global patterns of nutrient emission and deposition (N:P) are in turn closely reflected in the water chemistry of naturally oligotrophic lake (r2 = 0.81, p < 0.0001). Observed increases in anthropogenic N deposition play a role in nutrient concentrations (r2 = 0.02, p < 0.05); however, atmospheric deposition of P appears to be major contributor to this pattern (r2 = 0.65, p < 0.0001). Atmospheric simulations indicate a global increase in P deposition by 1.4 times the pre-industrial rate largely due to increased dust and biomass burning emissions. Although changes in the mass flux of global P deposition are smaller than for N, the impacts on primary productivity may be greater because, on average, one unit of increased P deposition has 16 times the influence of one unit of N deposition. These stoichiometric considerations, combined with the evidence presented here, suggest that increases in P deposition may be a major driver of alpine Lake trophic status, particularly in the Southern Hemisphere. These results underscore the need for the broader scientific community to consider the impact of atmospheric phosphorus deposition on the water quality of naturally oligotrophic lakes.

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Dynamics Of Thermally Induced Ice Streams Simulated With A Higher-Order Flow Model, Douglas Brinkerhoff, Jesse Johnson Sep 2015

Dynamics Of Thermally Induced Ice Streams Simulated With A Higher-Order Flow Model, Douglas Brinkerhoff, Jesse Johnson

Computer Science Faculty Publications

We use a new discretization technique to solve the higher-order thermomechanically coupled equations of glacier evolution. We find that under radially symmetric continuum equations, small perturbations in symmetry due to the discretization are sufficient to produce the initiation of non-symmetric thermomechanical instabilities which we interpret as ice streams, in good agreement with previous studies which have indicated a similar instability. We find that the inclusion of membrane stresses regularizes the size of predicted streams, eliminating the ill-posedness evident in previous investigations of ice stream generation through thermomechanical instability. Ice streams exhibit strongly irregular periodicity which is influenced by neighboring ice …

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The Nature And Frequency Of Outflows From Stars In The Central Orion Nebula Cluster, C. R. O'Dell, Gary J. Ferland, W. J. Henney, M. Peimbert, Ma. T. García-Díaz, Robert H. Rubin Sep 2015

The Nature And Frequency Of Outflows From Stars In The Central Orion Nebula Cluster, C. R. O'Dell, Gary J. Ferland, W. J. Henney, M. Peimbert, Ma. T. García-Díaz, Robert H. Rubin

Physics and Astronomy Faculty Publications

Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbig–Haro objects known within the inner Orion Nebula. We find that the best-known Herbig–Haro shocks originate from relatively few stars, with the optically visible X-ray source COUP 666 driving many of them. While some isolated shocks are driven by single collimated outflows, many groups of shocks are …

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Are We Making A Better World With Information And Communication Technology For Development (Ict4d) Research? Findings From The Field And Theory Building, Sajda Qureshi Sep 2015

Are We Making A Better World With Information And Communication Technology For Development (Ict4d) Research? Findings From The Field And Theory Building, Sajda Qureshi

Information Systems and Quantitative Analysis Faculty Publications

As Information and Communication Technologies (ICTs) continue to penetrate people’s lives the world over, there is a sense that understanding the role of ICTs in the context of development needs to be conceptualized theoretically while making empirical contributions that add to what we know (Avgerou, 2008; Davison, 2012; Sein and Harindranath, 2004; Sahay and Walsham, 1995). Other scholars have pointed to the importance of this research for the field of Information Systems (ISs) in offering broader contributions. Avgerou (2008) suggests that in the era of globalization such research offers contributions in ISs beyond “organizational organizational and national boundaries and support …

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Modeling Security And Resource Allocation For Mobile Multi-Hop Wireless Neworks Using Game Theory, Laurent L. Y. Njilla Sep 2015

Modeling Security And Resource Allocation For Mobile Multi-Hop Wireless Neworks Using Game Theory, Laurent L. Y. Njilla

FIU Electronic Theses and Dissertations

This dissertation presents novel approaches to modeling and analyzing security and resource allocation in mobile ad hoc networks (MANETs). The research involves the design, implementation and simulation of different models resulting in resource sharing and security’s strengthening of the network among mobile devices. Because of the mobility, the network topology may change quickly and unpredictably over time. Moreover, data-information sent from a source to a designated destination node, which is not nearby, has to route its information with the need of intermediary mobile nodes. However, not all intermediary nodes in the network are willing to participate in data-packet transfer of …

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Formaldehyde From E-Cigarettes - It's Not As Simple As Some Suggest, James F. Pankow, Robert M. Strongin, David H. Peyton Sep 2015

Formaldehyde From E-Cigarettes - It's Not As Simple As Some Suggest, James F. Pankow, Robert M. Strongin, David H. Peyton

Chemistry Faculty Publications and Presentations

The Authors address critics of a previously published letter to the Editor in The New England Journal of Medicine, pertaining to hidden formaldehyde in E-Cigarette aerosols and the need for future testing of their safety.

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Self-Accleration And Instability Of Gravity Wave Packets: 1. Effects Of Temporal Localization, David C. Fritts, Brian Laughman, Thomas S. Lund, Jonathan B. Snively Sep 2015

Self-Accleration And Instability Of Gravity Wave Packets: 1. Effects Of Temporal Localization, David C. Fritts, Brian Laughman, Thomas S. Lund, Jonathan B. Snively

Publications

"An anelastic numerical model is used to explore the dynamics accompanying the attainment of large amplitudes by gravity waves (GWs) that are localized in altitude and time. GW momentum transport induces mean flow variations accompanying a GW packet that grows exponentially with altitude, is localized in altitude, and induces significant GW phase speed, and phase, variations across the GW packet. These variations arise because the GW occupies the region undergoing accelerations, with the induced phase speed variations referred to as “self-acceleration.” Results presented here reveal that self-acceleration of a GW packet localized in time and altitude ultimately leads to stalling …

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Mercury Metallation Of The Copper Protein Azurin And Structural Insight Into Possible Heavy Metal Reactivity., Anthony Zampino, Francesca Masters, Erika Bladholm, Matthew Panzner, Steven Berry, Thomas Leeper, Christopher Ziegler Sep 2015

Mercury Metallation Of The Copper Protein Azurin And Structural Insight Into Possible Heavy Metal Reactivity., Anthony Zampino, Francesca Masters, Erika Bladholm, Matthew Panzner, Steven Berry, Thomas Leeper, Christopher Ziegler

Thomas C Leeper

Mercury(II) metallation of Pseudomonas aeruginosa azurin has been characterized structurally and biochemically. The X-ray crystal structure at 1.5 Å of mercury(II) metallated azurin confirms the coordination of mercury at the copper binding active site and a second surface site. These findings are further validated by NMR, Matrix-assisted laser desorption/ionization spectrometry (MALDI), and UV–visible spectroscopic methods indicating copper displacement from the wild-type protein. Bioinformatic analysis has identified homologous human protein domains computationally, and compared them to the structure of azurin, providing a model for human mercury interactions. Study of the mercury–azurin adduct, in combination with other known examples of protein–heavy metal …

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Mitoneet As A Novel Drug Target For Mitochondrial Dysfunction, Werner Geldenhuys, Thomas Leeper, Richard Carroll Sep 2015

Mitoneet As A Novel Drug Target For Mitochondrial Dysfunction, Werner Geldenhuys, Thomas Leeper, Richard Carroll

Thomas C Leeper

Mitochondrial dysfunction plays an important part in the pathology of several diseases, including Alzheimer's disease and Parkinson's disease. Targeting mitochondrial proteins shows promise in treating and attenuating the neurodegeneration seen in these diseases, especially considering their complex and pleiotropic origins. Recently, the mitochondrial protein mitoNEET [also referred to as CDGSH iron sulfur domain 1 (CISD1)] has emerged as the mitochondrial target of thiazolidinedione drugs such as the antidiabetic pioglitazone. In this review, we evaluate the current understanding regarding how mitoNEET regulates cellular bioenergetics as well as the structural requirements for drug compound association with mitoNEET. With a clear understanding of …

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Structural Libraries Of Protein Models For Multiple Species To Understand Evolution Of The Renin-Angiotensin System, Jeremy Prokop, Victoria Petri, Mary Shimoyama, Ingrid Watanabe, Dulce Casarini, Thomas Peeper, Stephanie Bilinovich, Howard Jacob, Robson Santos, Almir Martins, Fabiano Araujo, Fernando Reis, Amy Milsted Sep 2015

Structural Libraries Of Protein Models For Multiple Species To Understand Evolution Of The Renin-Angiotensin System, Jeremy Prokop, Victoria Petri, Mary Shimoyama, Ingrid Watanabe, Dulce Casarini, Thomas Peeper, Stephanie Bilinovich, Howard Jacob, Robson Santos, Almir Martins, Fabiano Araujo, Fernando Reis, Amy Milsted

Thomas C Leeper

The details of protein pathways at a structural level provides a bridge between genetics/molecular biology and physiology. The renin-angiotensin system is involved in many physiological pathways with informative structural details in multiple components. Few studies have been performed assessing structural knowledge across the system. This assessment allows use of bioinformatics tools to fill in missing structural voids. In this paper we detail known structures of the renin-angiotensin system and use computational approaches to estimate and model components that do not have their protein structures defined. With the subsequent large library of protein structures, we then created a species specific protein …

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