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Articles 301 - 330 of 517
Full-Text Articles in Chemistry
Substituent Effects On Reactivity And Allergenicity Of Benzoquinone, Wilbes Mbiya
Substituent Effects On Reactivity And Allergenicity Of Benzoquinone, Wilbes Mbiya
Dissertations and Theses
Benzoquinone (BQ) is an extremely potent electrophilic contact allergen that haptenates endogenous proteins through Michael addition (MA). It is also hypothesized that BQ may haptenate proteins via free radical formation. The objective of this study was to assess the inductive effects (activating and deactivating) of substituents on BQ reactivity and the mechanistic pathway of covalent binding to nucleophilic thiols. The BQ binding by Cys34 on human serum albumin was studied, and for reactivity studies, nitrobenzenethiol (NBT) was used as a surrogate for protein binding of the BQ and benzoquinone derivatives (BQD). Stopped flow techniques were used to determine pseudo-first order …
Developing Thyronamine Analog Pharmaceuticals Targeting Taar1 To Treat Methamphetamine Addiction, Troy Andrew Wahl
Developing Thyronamine Analog Pharmaceuticals Targeting Taar1 To Treat Methamphetamine Addiction, Troy Andrew Wahl
Dissertations and Theses
As a part of the overall program in the Grandy laboratory at Oregon Health & Science University (OHSU), studying the underlying chemical biology of methamphetamine (Meth) addiction, this dissertation reports on the development of six new thyronamine analogs which were synthesized and assayed against trace amine associated receptor 1 (TAAR1), giving preliminary results consistent with the analogs being inverse agonists. Due to highly variable TAAR1 expression levels in the assays, based on inter-assay response to control Meth stimulation as well as other possible factors, kinetic models were developed to qualitatively explain the assay results. The models set approximate limits on …
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
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
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 …
Training An Asymmetric Signal Perceptron In An Artificial Chemistry, Peter Banda
Training An Asymmetric Signal Perceptron In An Artificial Chemistry, Peter Banda
Student Research Symposium
Autonomous learning implemented purely by means of a synthetic chemical system has not been previously realized. Learning promotes reusability, and minimizes the system design to simple input-output specification. In this poster, I present a simulated chemical system, the first full-featured implementation of a perceptron in an artificial (simulated) chemistry, which can successfully learn all 14 linearly separable logic functions. A perceptron is the simplest system capable of learning inspired by the functioning of a biological neuron. My newest model called the asymmetric signal perceptron (ASP) is, as opposed to its predecessors such as the weight-race perceptron (WRP), substantially simpler by …
An Alternative Ribozyme For The Rna Hypercycle, Ishak Elkhal
An Alternative Ribozyme For The Rna Hypercycle, Ishak Elkhal
Student Research Symposium
In the quest to forward understanding of the prebiotic world (specifically, the RNA World Hypothesis), one of the most interesting paradigms to consider is the potential for cooperative networks that may have driven molecular evolution forward. Such a network may exist as an RNA hypercycle, as proposed by Eigen (1977). Much progress has been made towards an RNA hypercycle-like system, especially using the Azoarcus ribozyme system demonstrated by Vaidya et al. (2012). The current work is dedicated to constructing a second model as a cooperative RNA network, utilizing a group I intron from Coxiella burnetii (Cbu1917). The intron was constructed …
Use Of Soybean Lecithin In Shape Controlled Synthesis Of Gold Nanoparticles, Benjamin Robert Ayres
Use Of Soybean Lecithin In Shape Controlled Synthesis Of Gold Nanoparticles, Benjamin Robert Ayres
Dissertations and Theses
The work presented in this dissertation is a composite of experiments in the growth of gold nanoparticles with specific optical properties of interest. The goal is to synthesize these gold nanoparticles using soybean extract for not only shape control, but for propensity as a biocompatible delivery system. The optical properties of these nanoparticles has found great application in coloring glass during the Roman empire and, over the centuries, has grown into its own research field in applications of nanoparticulate materials. Many of the current functions include use in biological systems as biosensors and therapeutic applications, thus making biocompatibility a necessity. …
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
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
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 …
Online Learning In A Chemical Perceptron, Peter Banda, Christof Teuscher, Matthew R. Lakin
Online Learning In A Chemical Perceptron, Peter Banda, Christof Teuscher, Matthew R. Lakin
Computer Science Faculty Publications and Presentations
Autonomous learning implemented purely by means of a synthetic chemical system has not been previously realized. Learning promotes reusability and minimizes the system design to simple input-output specification. In this article we introduce a chemical perceptron, the first full-featured implementation of a perceptron in an artificial (simulated) chemistry. A perceptron is the simplest system capable of learning, inspired by the functioning of a biological neuron. Our artificial chemistry is deterministic and discrete-time, and follows Michaelis-Menten kinetics. We present two models, the weight-loop perceptron and the weight-race perceptron, which represent two possible strategies for a chemical implementation of linear integration and …
Model For Acid-Base Chemistry In Nanoparticle Growth (Mabnag), Taina Yli-Juuti, Kelley Barsanti, L. Hildebrandt Ruiz, Antti-Jussi Kieloaho, U. Makkonen, Tuukka Petäjä, Taina Ruuskanen, Markku Kulmala, Ilona Riipinen
Model For Acid-Base Chemistry In Nanoparticle Growth (Mabnag), Taina Yli-Juuti, Kelley Barsanti, L. Hildebrandt Ruiz, Antti-Jussi Kieloaho, U. Makkonen, Tuukka Petäjä, Taina Ruuskanen, Markku Kulmala, Ilona Riipinen
Civil and Environmental Engineering Faculty Publications and Presentations
Climatic effects of newly-formed atmospheric secondary aerosol particles are to a large extent determined by their condensational growth rates. However, all the vapours condensing on atmospheric nanoparticles and growing them to climatically relevant sizes are not identified yet and the effects of particle phase processes on particle growth rates are poorly known. Besides sulfuric acid, organic compounds are known to contribute significantly to atmospheric nanoparticle growth. In this study a particle growth model MABNAG (Model for Acid-Base chemistry in NAnoparticle Growth) was developed to study the effect of salt formation on nanoparticle growth, which has been proposed as a potential …
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
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 …
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
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 (ᵝabs), scattering (ᵝsca), and extinction (ᵝext) 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
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.
An Investigation Of Urban Mobile Source Aerosol Using Optical Properties Measured By Crdt/N: Diesel Particulate Matter And The Impact Of Biodiesel, Monica Elizabeth Wright
An Investigation Of Urban Mobile Source Aerosol Using Optical Properties Measured By Crdt/N: Diesel Particulate Matter And The Impact Of Biodiesel, Monica Elizabeth Wright
Dissertations and Theses
Mobile source emissions are a major contributor to global and local air pollution. Governments and regulatory agencies have been increasing the stringency of regulations in the transportation sector for the last ten years to help curb transportation sector air pollution. The need for regulations has been emphasized by scientific research on the impacts from ambient pollution, especially research on the effect of particulate matter on human health. The particulate emissions from diesel vehicles, diesel particulate matter (DPM) is considered a known or probable carcinogen in various countries and increased exposure to DPM is linked to increased cardiovascular health problems in …
Differential Effects Of The Hydrophobic Surfactant Proteins On The Formation Of Inverse Bicontinuous Cubic Phases, Mariya Chavarha, Ryan W. Loney, Kamlesh Kumar, Shankar B. Rananavare, Stephen B. Hall
Differential Effects Of The Hydrophobic Surfactant Proteins On The Formation Of Inverse Bicontinuous Cubic Phases, Mariya Chavarha, Ryan W. Loney, Kamlesh Kumar, Shankar B. Rananavare, Stephen B. Hall
Chemistry Faculty Publications and Presentations
Prior studies have shown that the biological mixture of the two hydrophobic surfactant proteins, SP-B and SP-C, produces faster adsorption of the surfactant lipids to an air/water interface, and that they induce 1-palmitoyl-2-oleoyl phosphatidylethanolamine (POPE) to form inverse bicontinuous cubic phases. SP-B has a much greater effect than SP-C on adsorption. If the two proteins induce formation of the bicontinuous structures and faster adsorption by similar mechanisms, then they should also have differential ability to form the cubic phases. To test this hypothesis, we measured small angle X-ray scattering on the individual proteins combined with POPE. SP-B replicated the doserelated …
Progress Toward Red And Near-Infrared (Nir) Emitting Saccharide Sensors, Martha Sibrian-Vazquez, Jorge O. Escobedo, Mark Lowry, Robert M. Strongin
Progress Toward Red And Near-Infrared (Nir) Emitting Saccharide Sensors, Martha Sibrian-Vazquez, Jorge O. Escobedo, Mark Lowry, Robert M. Strongin
Chemistry Faculty Publications and Presentations
Red-shifted and near-infrared (NIR)-active rhodamine analogs and their boronic acid derivatives were synthesized and studied. These latter compounds function as fluorogenic NIR active substrates for sugar sensing. The effects of benzannulation and boronic acid functionalization on fluorophore optical and sensing properties are described.
A Fast Response Highly Selective Probe For The Detection Of Glutathione In Human Blood Plasma, Yixing Guo, Xiaofeng Yang, Lovemore Hakuna, Aabha Barve, Jorge O. Escobedo, Mark Lowry, Robert M. Strongin
A Fast Response Highly Selective Probe For The Detection Of Glutathione In Human Blood Plasma, Yixing Guo, Xiaofeng Yang, Lovemore Hakuna, Aabha Barve, Jorge O. Escobedo, Mark Lowry, Robert M. Strongin
Chemistry Faculty Publications and Presentations
A fluorescent probe for glutathione (GSH) detection was developed. Our study indicates a possible mechanism which couples a conjugate addition and micelle-catalyzed large membered ring formation/elimination sequence. This method enables excellent selectivity towards GSH over other biological thiols such as cysteine (Cys) and homocysteine (Hcy). The proposed method is precise with a relative standard deviation (R.S.D) lower than 6% (n = 3) and has been successfully applied to determine GSH in human plasma with recoveries between 99.2% and 102.3%.
Chemical Exchange Saturation Transfer Is Unaffected By Modest Changes In Pressure, Benjamin Charles Webber, Christiane A. Carney, Mark Woods
Chemical Exchange Saturation Transfer Is Unaffected By Modest Changes In Pressure, Benjamin Charles Webber, Christiane A. Carney, Mark Woods
Chemistry Faculty Publications and Presentations
ParaCEST (paramagnetic Chemical Exchange Saturation Transfer) agents offer an unparalleled opportunity to perform quantitative molecular imaging by MRI. Agents that can alter the image contrast they generate in response to changes in local environmental parameters such as pH, glucose concentration or lactate concentration can be used ratiometrically to quantitatively describe the local tissue environment. However, when performing such quantitative measurements it is important that the results are not confounded by changes in a second environmental parameter. In vivo pressure varies quite considerably, both through the respiratory cycle and from tissue to tissue (tumors in particular have high interstitial pressures). Since …
Reversed Chloroquine Molecules As A Strategy To Overcome Resistance In Malaria, David H. Peyton
Reversed Chloroquine Molecules As A Strategy To Overcome Resistance In Malaria, David H. Peyton
Chemistry Faculty Publications and Presentations
This short review tells the story of how Reversed Chloroquine drugs (RCQs) were developed. These are hybrid molecules, made by combining the quinoline nucleus from chloroquine (CQ) with moieties which are designed to inhibit efflux via known transporters in the membrane of the digestive vacuole of the malaria parasite. The resulting RCQ drugs can have potencies exceeding that of CQ, while at the same time having physical chemical characteristics that may make them favorable as partner drugs in combination therapies. The need for such novel antimalarial drugs will continue for the foreseeable future.
Functional Promiscuity Of The Cog0720 Family, Gabriela Phillips, Laura L. Grochowski, Shilah Bonnett, Huimin Xu, Marc Bailly, Crysten Haas-Blaby, Basma El Yacoubi, Dirk Iwata-Reuyl, Robert H. White, Valérie De Crécy-Lagard
Functional Promiscuity Of The Cog0720 Family, Gabriela Phillips, Laura L. Grochowski, Shilah Bonnett, Huimin Xu, Marc Bailly, Crysten Haas-Blaby, Basma El Yacoubi, Dirk Iwata-Reuyl, Robert H. White, Valérie De Crécy-Lagard
Chemistry Faculty Publications and Presentations
The biosynthesis of GTP derived metabolites such as tetrahydrofolate (THF), biopterin (BH4), and the modified tRNA nucleosides queuosine (Q) and archaeosine (G+) relies on several enzymes of the Tunnel-fold superfamily. A subset of these proteins include the 6-pyruvoyl-tetrahydropterin (PTPS-II), PTPS-III, and PTPS-I homologs, all members of the COG0720 family, that have been previously shown to transform 7,8-dihydroneopterin triphosphate (H2NTP) into different products. PTPS-II catalyzes the formation of 6-pyruvoyltetrahydropterin in the BH4 pathway. PTPS-III catalyzes the formation of 6-hydroxylmethyl-7,8-dihydropterin in the THF pathway. PTPS-I catalyzes the formation of 6-carboxy-5,6,7,8-tetrahydropterin in the Q pathway. Genes of these …
Surfactant-Free Hybridization Of Transition Metal Oxide Nanoparticles With Conductive Graphene For High-Performance Supercapacitor, Wen Qian, Zhiqiang Chen, Steven Cottingham, William Alexander Merrill, Natasja A. Swartz, Andrea Goforth, Tami Lasseter Clare, Jun Jiao
Surfactant-Free Hybridization Of Transition Metal Oxide Nanoparticles With Conductive Graphene For High-Performance Supercapacitor, Wen Qian, Zhiqiang Chen, Steven Cottingham, William Alexander Merrill, Natasja A. Swartz, Andrea Goforth, Tami Lasseter Clare, Jun Jiao
Chemistry Faculty Publications and Presentations
In order to improve specific capacitance and limit electrical resistance, high-quality exfoliatedgraphene decorated with transition metal (Fe, Mn, Co) oxide nanoparticles (NPs) has been successfully synthesized without the use of surfactant via a simple, general, environmentally-friendly chemical process. The specific capacitance of as-prepared graphene/Mn3O4 composite reach 239.6 F/g, when employed as the anode material in neutral NaCl electrolyte solutions (cf. 98.2 F/g for pristine graphene and 141.4 F/g for pure Mn3O4 NPs), which indicate the synergetic effects from both graphene and attached Mn3O4 NPs. Moreover, the high conductivity of …
Diversity Of Archaeosine Synthesis In Crenarchaeota, Gabriela Phillips, Manal A. Swairjo, Kirk W. Gaston, Marc Bailly, Patrick A. Limbach, Dirk Iwata-Reuyl, Valérie De Crécy-Lagard
Diversity Of Archaeosine Synthesis In Crenarchaeota, Gabriela Phillips, Manal A. Swairjo, Kirk W. Gaston, Marc Bailly, Patrick A. Limbach, Dirk Iwata-Reuyl, Valérie De Crécy-Lagard
Chemistry Faculty Publications and Presentations
Archaeosine (G+) is found at position 15 of many archaeal tRNAs. In Euryarchaeota, the G+ precursor, 7-cyano-7-deazaguanine (preQ0), is inserted into tRNA by tRNA-guanine transglycosylase (arcTGT) before conversion into G+ by ARChaeosine Synthase (ArcS). However, many Crenarchaeota known to harbor G+ lack ArcS homologs. Using comparative genomics approaches, two families that could functionally replace ArcS in these organisms were identified: 1) GAT-QueC, a two-domain family with an N-terminal glutamine amidotransferase class-II domain fused to a domain homologous to QueC, the enzyme that produces preQ0; 2) QueF-like, a family homologous to the bacterial enzyme catalyzing the reduction of preQ0 to 7- …
Advanced Nanohybrid Materials: Surface Modification And Applications, Li-Hung Liu, Rémi Métivier, Shanfeng Wang, Hui Wang
Advanced Nanohybrid Materials: Surface Modification And Applications, Li-Hung Liu, Rémi Métivier, Shanfeng Wang, Hui Wang
Chemistry Faculty Publications and Presentations
The field of functional nanoscale hybrid materials is one of the most promising and rapidly emerging research areas in materials chemistry. Nanoscale hybrid materials can be broadly defined as synthetic materials with organic and inorganic components that are linked together by noncovalent bonds (Class I, linked by hydrogen bond, electrostatic force, or van der Waals force) or covalent bonds (Class II) at nanometer scale. The unlimited possible combinations of the distinct properties of inorganic, organic, or even bioactive components in a single material, either in molecular or nanoscale dimensions, have attracted considerable attention. This approach provides an opportunity to create …
Identification Of The Biogenic Compounds Responsible For Size-Dependent Nanoparticle Growth, Paul M. Winkler, John Ortega, Thomas Karl, Luca Cappellin, Hans R. Friedli, Kelley Barsanti, Peter H. Mcmurry, James N. Smith
Identification Of The Biogenic Compounds Responsible For Size-Dependent Nanoparticle Growth, Paul M. Winkler, John Ortega, Thomas Karl, Luca Cappellin, Hans R. Friedli, Kelley Barsanti, Peter H. Mcmurry, James N. Smith
Civil and Environmental Engineering Faculty Publications and Presentations
The probability that freshly nucleated nanoparticles can survive to become cloud condensation nuclei is highly sensitive to particle growth rates. Much of the growth of newly formed ambient nanoparticles can be attributed to oxidized organic vapors originating from biogenic precursor gases. In this study we investigated the chemical composition of size-selected biogenic nanoparticles in the size range from 10 to 40 nm. Particles were formed in a flow tube reactor by ozonolysis ofα-pinene and analyzed with a Thermal Desorption Chemical Ionization Mass Spectrometer. While we found similar composition in 10 and 20 nm particles, the relative amounts of …
A Seminaphthofluorescein-Based Fluorescent Chemodosimeter For The Highly Selective Detection Of Cysteine, Xiaofeng Yang, Yixing Guo, Robert M. Strongin
A Seminaphthofluorescein-Based Fluorescent Chemodosimeter For The Highly Selective Detection Of Cysteine, Xiaofeng Yang, Yixing Guo, Robert M. Strongin
Chemistry Faculty Publications and Presentations
A fluorescent chemodosimeter for cysteine detection was developed based on a tandem conjugate addition and intramolecular cyclization reaction. The method exhibited an excellent selectivity for cysteine over other biothiols such as homocysteine and glutathione.
Overview Of The 2010 Carbonaceous Aerosols And Radiative Effects Study (Cares), Rahul A. Zaveri, William J. Shaw, Daniel J. Cziczo, Beat Schmid, Richard Ferrare, M. Lizabeth Alexander, Raul Alvarez, W. Patrick Arnott, Dean B. Atkinson, Sunil Baidar, Robert M. Banta, James Barnard, Josef Beranek, Larry K. Berg, Fred Brechtel, W. Alan Brewer, John F. Cahill, Brian Cairns, Christopher D. Cappa, D. Chand, S. China, Jennifer M. Comstock, Manvendra K. Dubey, Robert C. Easter, M. H. Erickson, Jerome Fast, Cody Floerchinger, B. Flowers, Edward C. Fortner, Jeffrey S. Gaffney, Mary K. Gilles, Kyle Gorkowski, William Gustafson, Madhu Gyawali, J. Hair, R. M. Hardesty, Joseph Harworth, Scott C. Herndon, Naruki Hiranuma, Chris Hostetler, John M. Hubbe, John T. Jayne, H. Jeong, B. Tom Jobson, Evgueni Kassianov, Lawrence I. Kleinman, C. Kluzek, W. Berk Knighton, Katheryn R. Kolesar, Chongai Kuang, Alena Kubátová, Andrew O. Langford, Alexander Laskin, N. Laulainen, Richard D. Marchbanks, Claudio Mazzoleni, Fan Mei, Ryan C. Moffet, Dan Nelson, Michael Obland, Hilke Oetjen, Timothy B. Onasch, I. Ortega, Matteo Ottaviani, Mikhail Pekour, Kimberly A. Prather, James Gregory Radney, Raymond R. Rogers, Scott P. Sandberg, Arthur J. Sedlacek, Christoph J. Senff, Gunnar I. Senum, Ari Setyan, John E. Shilling, Manishkumar Shrivastava, C. Song, Stephen R. Springston, R. Subramanian, Kaitlyn Suski, Jason Tomlinson, Rainer M. Volkamer, H. W. Wallace, Jian Wang, A. M. Weickmann, Douglas R. Worsnop, Xiao-Ying Yu, Alla Zelenyuk, Qi Zhang
Overview Of The 2010 Carbonaceous Aerosols And Radiative Effects Study (Cares), Rahul A. Zaveri, William J. Shaw, Daniel J. Cziczo, Beat Schmid, Richard Ferrare, M. Lizabeth Alexander, Raul Alvarez, W. Patrick Arnott, Dean B. Atkinson, Sunil Baidar, Robert M. Banta, James Barnard, Josef Beranek, Larry K. Berg, Fred Brechtel, W. Alan Brewer, John F. Cahill, Brian Cairns, Christopher D. Cappa, D. Chand, S. China, Jennifer M. Comstock, Manvendra K. Dubey, Robert C. Easter, M. H. Erickson, Jerome Fast, Cody Floerchinger, B. Flowers, Edward C. Fortner, Jeffrey S. Gaffney, Mary K. Gilles, Kyle Gorkowski, William Gustafson, Madhu Gyawali, J. Hair, R. M. Hardesty, Joseph Harworth, Scott C. Herndon, Naruki Hiranuma, Chris Hostetler, John M. Hubbe, John T. Jayne, H. Jeong, B. Tom Jobson, Evgueni Kassianov, Lawrence I. Kleinman, C. Kluzek, W. Berk Knighton, Katheryn R. Kolesar, Chongai Kuang, Alena Kubátová, Andrew O. Langford, Alexander Laskin, N. Laulainen, Richard D. Marchbanks, Claudio Mazzoleni, Fan Mei, Ryan C. Moffet, Dan Nelson, Michael Obland, Hilke Oetjen, Timothy B. Onasch, I. Ortega, Matteo Ottaviani, Mikhail Pekour, Kimberly A. Prather, James Gregory Radney, Raymond R. Rogers, Scott P. Sandberg, Arthur J. Sedlacek, Christoph J. Senff, Gunnar I. Senum, Ari Setyan, John E. Shilling, Manishkumar Shrivastava, C. Song, Stephen R. Springston, R. Subramanian, Kaitlyn Suski, Jason Tomlinson, Rainer M. Volkamer, H. W. Wallace, Jian Wang, A. M. Weickmann, Douglas R. Worsnop, Xiao-Ying Yu, Alla Zelenyuk, Qi Zhang
Chemistry Faculty Publications and Presentations
Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program’s Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was …
Spontaneous Cooperative Assembly Of Replicative Catalytic Rna Systems, Nilesh Vaidya
Spontaneous Cooperative Assembly Of Replicative Catalytic Rna Systems, Nilesh Vaidya
Dissertations and Theses
The RNA World hypothesis proposes a period of time during the origins of life in which RNA molecules were the only source of both genotypes and phenotypes. Although a vast amount of evidence has been obtained in support of this hypothesis, a few critical demonstrations are lacking. A most crucial one is a demonstration of self-replication of RNA molecule from prebiotic soup. Previously in the Lehman laboratory, it has been demonstrated that a 198-nucleotide molecule derived from the Azoarcus group I intron can self-assemble from up to four fragments of RNA via recombination. Furthermore, the covalent full-length molecules are catalytically …
Biosynthesis Of Marineosin, A Spiroaminal Undecylprodiginine Natural Product, Shaimaa Mohamed Salem
Biosynthesis Of Marineosin, A Spiroaminal Undecylprodiginine Natural Product, Shaimaa Mohamed Salem
Dissertations and Theses
Marineosins A and B are two spiroaminal-ring containing tripyrrole compounds isolated from the marine actinomycete, Streptomyces CNQ-617, and were found to possess potent and selective cytotoxic activity against leukemia and melanoma. Marineosins belong to the prodiginines class of natural products, examples of which are undecylprodiginine and streptorubin B. Unlike marineosins, prodiginines structures are characterized by the presence of fully conjugated tripyrrole nucleus linked to an alkyl chain (that lacks any oxygen). Cyclic prodiginines arise from an oxidative cyclization of the alkyl chain onto the tripyrrole, a step catalyzed by Rieske-oxygenase like enzymes such as RedG. The biosynthesis of prodiginines is …
Understanding The Emission From Semiconductor Nanoparticles, Beth Ann Manhat
Understanding The Emission From Semiconductor Nanoparticles, Beth Ann Manhat
Dissertations and Theses
This dissertation describes the synthesis and characterization of fluorescent semiconductor nanoparticles (NPs) in order to optimize their biomedical utility for imaging and sensing applications. While both direct and indirect bandgap semiconductor NPs have been studied, control over their emission properties vary. Quantum confinement (QC), which primarily controls the emission wavelength of nanosized semiconductors, dictates that as the size of semiconductor NPs decrease, the magnitude of the bandgap increases, resulting in changes in the observed emission wavelength: smaller NPs have a larger bandgap, and thus a bluer emission. However, surface, interfacial, or shell defects can act as non-radiative or radiative recombination …