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Full-Text Articles in Physical Sciences and Mathematics

Coupling Fast Water Exchange To Slow Molecular Tumbling In Gd3+ Chelates: Why Faster Is Not Always Better, Stefano Avedano, Mauro Botta, Julian Saunders Haigh, Dario L. Lango, Mark Woods Jul 2013

Coupling Fast Water Exchange To Slow Molecular Tumbling In Gd3+ Chelates: Why Faster Is Not Always Better, Stefano Avedano, Mauro Botta, Julian Saunders Haigh, Dario L. Lango, Mark Woods

Chemistry Faculty Publications and Presentations

The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd3+ chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of monohydrated Gd3+ chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd3+–water proton distance (rGdH), and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd3+ chelate as a potential contrast agent. The consequence of this omission can be seen when considering …


Identification Of Cisplatin-Binding Proteins Using Agarose Conjugates Of Platinum Compounds, Takatoshi Karasawa, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger Jun 2013

Identification Of Cisplatin-Binding Proteins Using Agarose Conjugates Of Platinum Compounds, Takatoshi Karasawa, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger

Chemistry Faculty Publications and Presentations

Cisplatin is widely used as an antineoplastic drug, but its ototoxic and nephrotoxic side-effects, as well as the inherent or acquired resistance of some cancers to cisplatin, remain significant clinical problems. Cisplatin’s selectivity in killing rapidly proliferating cancer cells is largely dependent on covalent binding to DNA via cisplatin’s chloride sites that had been aquated. We hypothesized that cisplatin’s toxicity in slowly proliferating or terminally differentiated cells is primarily due to drug-protein interactions, instead of drug-DNA binding. To identify proteins that bind to cisplatin, we synthesized two different platinum-agarose conjugates, one with two amino groups and another with two chlorides …


Picture Of A Chelate In Exchange: The Crystal Structure Of Nahodotma, A 'Semi'-Hydrated Chelate, Katherine M. Payne, Edward J. Valente, Silvio Aime, Mauro Botta, Mark Woods Feb 2013

Picture Of A Chelate In Exchange: The Crystal Structure Of Nahodotma, A 'Semi'-Hydrated Chelate, Katherine M. Payne, Edward J. Valente, Silvio Aime, Mauro Botta, Mark Woods

Chemistry Faculty Publications and Presentations

Crystallography generally only provides static structural information. This can render it an ineffective technique for probing dynamic solution state processes. A crystal of HoDOTMA affords unique structures that effectively represent that of a lanthanide tetra-acetate chelate mid-way through the water exchange process.


Dimethyl Sulfoxide (Dmso) Exacerbates Cisplatin-Induced Sensory Hair Cell Death In Zebrafish (Danio Rerio), Phillip M. Uribe, Melissa A. Mueller, Julia S. Gleichman, Matthew D. Kramer, Qi Wang, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger, Douglas A. Cotanche, Jonathan I. Matsui Feb 2013

Dimethyl Sulfoxide (Dmso) Exacerbates Cisplatin-Induced Sensory Hair Cell Death In Zebrafish (Danio Rerio), Phillip M. Uribe, Melissa A. Mueller, Julia S. Gleichman, Matthew D. Kramer, Qi Wang, Martha Sibrian-Vazquez, Robert M. Strongin, Peter S. Steyger, Douglas A. Cotanche, Jonathan I. Matsui

Chemistry Faculty Publications and Presentations

Inner ear sensory hair cells die following exposure to aminoglycoside antibiotics or chemotherapeutics like cisplatin, leading to permanent auditory and/or balance deficits in humans. Zebrafish (Danio rerio) are used to study drug-induced sensory hair cell death since their hair cells are similar in structure and function to those found in humans. We developed a cisplatin dose-response curve using a transgenic line of zebrafish that expresses membrane-targeted green fluorescent protein under the control of the Brn3c promoter/enhancer. Recently, several small molecule screens have been conducted using zebrafish to identify potential pharmacological agents that could be used to protect sensory hair cells …


Evolution Of Multispectral Aerosol Optical Properties In A Biogenically-Influenced Urban Environment During The Cares Campaign, Madhu Gyawali, W. Patrick Arnott, Rahul A. Zaveri, C. Song, Mikhail Pekour, B. Flowers, Manvendra K. Dubey, Ari Setyan, Qi Zhang, Joseph Harworth, James Gregory Radney, Dean B. Atkinson, S. China, Claudio Mazzoleni, Kyle Gorkowski, R. Subramanian, B. Tom Jobson, Hans Moosmüller Jan 2013

Evolution Of Multispectral Aerosol Optical Properties In A Biogenically-Influenced Urban Environment During The Cares Campaign, Madhu Gyawali, W. Patrick Arnott, Rahul A. Zaveri, C. Song, Mikhail Pekour, B. Flowers, Manvendra K. Dubey, Ari Setyan, Qi Zhang, Joseph Harworth, James Gregory Radney, Dean B. Atkinson, S. China, Claudio Mazzoleni, Kyle Gorkowski, R. Subramanian, B. Tom Jobson, Hans Moosmüller

Chemistry Faculty Publications and Presentations

Ground-based aerosol measurements made in June 2010 within Sacramento urban area (site T0) and at a 40-km downwind location (site T1) in the forested Sierra Nevada foothills area are used to investigate the evolution of multispectral optical properties as the urban aerosols aged and interacted with biogenic emissions. Along with black carbon and non-refractory aerosol mass and composition observations, spectral absorption (abs), scattering (sca), and extinction (ext) coefficients for wavelengths ranging from 355 to 1064nm were measured at both sites using photoacoustic (PA) instruments with integrating nephelometers and using cavity ring-down (CRD) instruments. The …


Robust Visible Light Photoswitching With Ortho-Thiol Substituted Azobenzenes, Subhas Samanta, Theresa M. Mccormick, Simone K. Schmidt, Dwight S. Seferos, G. Andrew Woolley Jan 2013

Robust Visible Light Photoswitching With Ortho-Thiol Substituted Azobenzenes, Subhas Samanta, Theresa M. Mccormick, Simone K. Schmidt, Dwight S. Seferos, G. Andrew Woolley

Chemistry Faculty Publications and Presentations

Introduction of S-ethyl groups in all four ortho positions of azobenzene prevents reduction of the azo group by intracellular glutathione, while enhancing the absorptivity to ∼10000 M−1 cm−1 in the blue and green regions of the visible spectrum. cis-to-trans isomerization occurs thermally on the minutes timescale. Further, this substitution pattern permits switching with red light, a color that is more penetrating through biological tissues than other parts of the visible spectrum.


Aqueous Red-Emitting Silicon Nanoparticles For Cellular Imaging: Consequences Of Protecting Against Surface Passivation By Hydroxide And Water For Stable Red Emission, Sheng-Kuei Chiu, Beth Ann Manhat, William J.I. Debenedetti, Anna L. Brown, Katye Fichter, Tania Vu, Micah Eastman, Jun Jiao, Andrea Mitchell Goforth Jan 2013

Aqueous Red-Emitting Silicon Nanoparticles For Cellular Imaging: Consequences Of Protecting Against Surface Passivation By Hydroxide And Water For Stable Red Emission, Sheng-Kuei Chiu, Beth Ann Manhat, William J.I. Debenedetti, Anna L. Brown, Katye Fichter, Tania Vu, Micah Eastman, Jun Jiao, Andrea Mitchell Goforth

Chemistry Faculty Publications and Presentations

Stable, aqueous, red-to-near infrared emission is critical for the use of silicon nanoparticles (Si NPs) in biological fluorescence assays, but such Si NPs have been difficult to attain. We report a synthesis and surface modification strategy that protects Si NPs and preserves red photoluminescence (PL) in water for more than 6 mo. The Si NPs were synthesized via high temperature reaction, liberated from an oxide matrix, and functionalized via hydrosilylation to yield hydrophobic particles. The hydrophobic Si NPs were phase transferred to water using the surfactant cetyltrimethylammonium bromide (CTAB) with retention of red PL. CTAB apparently serves a double role …