WorldCat Identities

Indiana University, Bloomington Department of Chemistry

Overview
Works: 340 works in 375 publications in 1 language and 2,798 library holdings
Genres: Academic theses 
Roles: Researcher
Classifications: QD1000,
Publication Timeline
.
Most widely held works about Bloomington Indiana University
 
Most widely held works by Bloomington Indiana University
Homogeneous C--H activation and redox chemistry of PNP-supported organotitanium complexes by Vincent N Cavaliere( )

1 edition published in 2012 in English and held by 63 WorldCat member libraries worldwide

One of the most important challenges facing chemists, fundamentally and practically speaking, is the efficient and mild activation and functionalization of the major components of natural gas: methane, ethane, and other alkanes. New lab-scale techniques to this end are needed to supplement the industrial standards in this area, such as steam reforming, cracking, and the Fischer-Tropsch process, which are energy and capital-intensive. The transient titanium alkylidyne is now shown to cleave the C--H bonds of the most inert organic molecules, methane, heavier alkanes, under mild conditions. Methane reacts to form a stable titanium-methyl bond, and careful deuterium labeling and kinetics studies show rapid tautomerization processes in this molecules, implicating a terminal, transient titanium methylidene
Development and deployment of instrumentation to measure total hydroxyl radical reactivity in the atmosphere by Robert Frederick Hansen( )

1 edition published in 2014 in English and held by 63 WorldCat member libraries worldwide

The hydroxyl radical (OH) is an important atmospheric oxidant that plays a key role in the formation of tropospheric ozone and secondary organic aerosols and controls the lifetime of atmospheric trace gases that contribute to global climate change. A complete understanding of OH sources and sinks is therefore essential to understand these processes. Total hydroxyl radical (OH) reactivity, the inverse of the lifetime of OH, is an important metric of OH chemistry and can be used to investigate OH sources and sinks. Notably, OH reactivity has been used to investigate OH sink budgets by comparing the OH reactivity calculated from measurements of trace gas concentrations to that measured directly by one of several techniques. Comparisons of measured and calculated OH reactivity from field measurement campaigns have yielded discrepancies in both urban and forested environments, which suggest the presence of unknown OH sinks
Peptide ion conformation studies and the 157 nm photofragmentation of arginine containing dipeptides by Nathaniel T Webber( )

1 edition published in 2012 in English and held by 63 WorldCat member libraries worldwide

Mass spectrometry is a powerful tool that has become a popular method for the analysis of biological molecules, such as proteins and sugars. A challenge when dealing with biological molecules is that there can be many gas phase conformations of the same molecule, and these conformations may fragment differently. It can also be difficult to differentiate structural isomers. Ion mobility spectrometry (IMS) utilizes a uniform electric field and a buffer gas to separate ions based on their collisional cross sectional area. This enables the separation of conformations and structural isomers. Ultraviolet (UV) photodissociation can then be used to deposit a large but well-defined amount of energy into these ions, producing informative high-energy photofragments that can be used for elucidating the ion's structure
Charge detection mass spectrometry : improved charge precision and applications to bacteriophage P22 by David Z Keifer( )

1 edition published in 2016 in English and held by 63 WorldCat member libraries worldwide

In CDMS, both the m/z and the charge are measured simultaneously for individual ions. Multiplying those measurements for each ion yields the mass. Thus, there is no need for charge state resolution in an m/z spectrum. CDMS can therefore be used to measure the masses of extremely heavy and heterogeneous analytes far beyond the capabilities of conventional MS. This comes at the cost of efficiency, since single ions are measured serially, and resolution, since the charge measurement historically has been imprecise in CDMS
Measurement of ion transport in biological monolayers with scanning ion conductance microscopy by Yi Zhou( )

1 edition published in 2014 in English and held by 63 WorldCat member libraries worldwide

Ion transport regulated by protein channels is of great importance in biological systems. Such regulation is highly sensitive and selective. The nature of channel architecture and permeability have been and remain an important area of research. Since the introduction of scanning ion conductance microscopy (SICM), significant effort has been directed toward high resolution topographic imaging of delicate biological samples. Recently, a key feature of SICM, the precise control of probe positions, has been explored with multifunctional probes to obtain local conductance and electrochemical information. In work described here, modifications to SICM were made for the study of ion transport regulated by tight junction proteins in cell monolayers. Modifications include a four-electrode setup (compared to the original two-electrode setup), which allowed localized measurement of heterogeneous conductance on a porous membrane. Further addition of a fifth electrode transformed traditional current recording of SICM to potentiometric measurements, which significantly increased the signal-to-noise ratios and allowed measurement in biological monolayers. With the aid of well-defined samples prepared by focused ion beam, mechanisms of potentiometric-SICM (P-SICM) were studied in detail. P-SICM was then applied to study the interaction of claudin-16 and claudin-19, which are tight junction proteins that control ion transport through cell junctions. With live-cell fluorescence microscopy, cells that expressed unique claudins were identified and targeted with P-SICM. In addition to advances in instrument configuration, the scanning probe of SICM was modified with ion channels inserted in a lipid bilayer at the pipet tip. Such ion channel probes (ICPs) combine the precise position control of SICM with the powerful sensing of ion channels. Approach curves and preliminary imaging performed with ICPs are described in detail. Developments for SICM reported here extend applications available for the study of biological transport
Manipulating the architecture of bimetallic nanostructures and their plasmonic properties by Christopher John DeSantis( Visual )

1 edition published in 2014 in English and held by 62 WorldCat member libraries worldwide

There has been much interest in colloidal noble metal nanoparticles due to their fascinating plasmonic and catalytic properties. These properties make noble metal nanoparticles potentially useful for applications such as targeted drug delivery agents and hydrogen storage devices. Historically, shape-controlled noble metal nanoparticles have been predominantly monometallic. Recent synthetic advances provide access to bimetallic noble metal nanoparticles wherein their inherent multifunctionality and ability to fine tune or expand their surface chemistry and light scattering properties of metal nanoparticles make them popular candidates for many applications. Even so, there are currently few synthetic strategies to rationally design shape-controlled bimetallic nanocrystals; for this reason, few architectures are accessible. For example, the "seed-mediated method" is a popular means of achieving monodisperse shape-controlled bimetallic nanocrystals.^
Dynamics and conformational heterogeneity in cytochrome P450s via infrared spectroscopy by Edward J Basom( )

1 edition published in 2017 in English and held by 61 WorldCat member libraries worldwide

Cytochrome P450s (P450s) are a superfamily of enzymes that catalyze oxidation of unactivated hydrocarbons. However, the means by which P450s control (1) regioselectivity of their activity and (2) specificity in their molecular recognition remain largely elusive. Toward investigation of the role of dynamics in the regioselectivity of the archetypal cytochrome P450cam (P450cam), two-dimensional infrared spectroscopy has been applied with heme-bound carbon monoxide (CO) as an infrared probe of the active site. The data support a model for P450cam regioselectivity in which binding of different substrates to P450cam variably stabilizes the active site into two distinct states, each associated with different dynamics linked to different levels of regioselectivity. To investigate the role of conformational heterogeneity in P450cam substrate specificity, infrared spectoscopy was combined with the site-specific incorporation of nitrile probes at distinct P450cam microenvironments. This approach enabled differentiation of changes experienced at each of those environments when d-camphor and/or CO binds to the active site. Finally, the impact of conformational heterogeneity on the affinity of substrate molecular recognition by wild-type and mutant P450cam was evaluated using both CO and nitrile probes. This study suggests that the nature of the conformations populated in the unbound states influences the affinity for different substrates. Collectively, these studies provide new insight into the roles of conformational heterogeneity and dynamics in P450cam activity. Furthermore, these studies help to lay the foundation for efforts toward understanding the roles of conformational heterogeneity and dynamics in the function of human P450s, for which unraveling the mechanisms involved in Phase I metabolism is a topic of great pharmacological concern
Using induced signals to develop a position-sensitive microchannel plate detector by Bryan Blake Wiggins( )

1 edition published in 2017 in English and held by 61 WorldCat member libraries worldwide

A novel concept to provide position-sensitivity to a microchannel plate (MCP) is described. While several designs exist to make MCPs position sensitive, all these designs are based upon collection of the electrons. In contrast, this approach utilizes an induced signal as the electron cloud emanates from an MCP and passes a wire plane. We demonstrate the validity of the concept by constructing a device that provides single electron detection with 98 mum position resolution (FWHM) over an area of 50 mm x 50 mm. The characteristics of the detector are described through both bench-top tests and simulation. After characterization of the detector, the sense wire detector was utilized for slow-neutron radiography. Furthermore, we utilized our knowledge of position-sensitive techniques to realize a beam-imaging MCP detector useful for radioactive beam facilities
Hydroxyl, hydroperoxyl, and organic peroxy radical chemistry in forested areas : measurements, modeling and implications for atmospheric chemistry by Michelle Mikiko Lew( )

1 edition published in 2017 in English and held by 61 WorldCat member libraries worldwide

The hydroxyl (OH) and the hydroperoxyl (HO2) are the primary oxidants in the atmosphere. In addition to controlling lifetimes of many trace gases, OH radicals react with volatile organic compounds (VOCs) emitted from both natural and anthropogenic sources leading to the production of ozone and secondary organic aerosols in the atmosphere. Accurate concentration measurements of OH and HO2 radicals in the atmosphere can provide an important test of our understanding of atmospheric chemistry and its implications to air quality. Recent measurements of OH radicals have often been greater than model predictions, questioning our understanding of this important chemistry. Measurements of these radicals presents a difficult analytical challenge, as the typical ambient concentration of the hydroxyl radical is less than 0.05 parts per trillion due to its high reactivity and short chemical lifetime in the atmosphere
On the development of tools to further understand and kill bacteria by Jonathan Thomas Rittichier( )

2 editions published in 2016 in English and held by 11 WorldCat member libraries worldwide

Tripropeptins, empedopeptin and plusbacins (collectively known as TEPins) are a general class of lipodepsipeptide antibiotics that make interesting synthetic targets. Even more importantly to our group, the TEPins display excellent activity against many Gram-positive bacteria - most notably, methicillin resistant S. aureus (MRSA) and VanA-type vancomycin-resistant enterococci (VRE). We have recently developed a unified solid-phase synthesis for these antibiotics allowing us to further study their mechanism of action as well as rapidly access analogs in hopes of providing new weapons to better kill bacteria
Design and synthesis of fluorous protecting groups amenable to automated solution-phase synthesis of biologically active oligosaccharides by Rajarshi Roy Choudhury( )

2 editions published in 2014 in English and held by 11 WorldCat member libraries worldwide

Fluorous protecting group-assisted synthesis of oligosaccharides from monosaccharide building blocks has been popular for a decade owing to its unique purification advantages over more traditional methods. In this dissertation, first ever photo-labile fluorous protecting groups and their use in automated solution-phase synthesis of oligosaccharides are introduced. Also, first demonstration of generation of adaptive immune response against neutral carbohydrate structures in the context of Leishmaniasis is reported in this dissertation. Additionally, scope of synthetic glycans in designing carbohydrate based adjuvants against several infectious diseases are highlighted
Charge detection mass spectrometry and a frequency scanned linear quadrupole : mass analysis of large ions by Deven Lee Shinholt( )

2 editions published in 2014 in English and held by 11 WorldCat member libraries worldwide

Mass spectrometry (MS) has been a valuable analytical tool since J.J. Thomson first studied ion beams at the turn of the 20th century. When Whitehouse and Fenn coupled electrospray ionization to a quadrupole mass spectrometer, MS entered a new regime, where large ions were accessible for mass analysis. Although small proteins and peptides are relatively straightforward, analysis of much larger proteins and complexes (e.g., viruses and DNA) becomes much more difficult due to charge state convolution. Charge detection MS (CDMS) circumvents this issue by directly measuring the charge and m/z of each ion individually, allowing for the m/z spectrum to be directly deconvoluted into a true mass spectrum. This technique does not currently measure with high resolution, but a direct charge measurement is an advantage that is not available with other charge imaging techniques, for instance FTICR-MS or Orbitrap MS. Several projects were undertaken to improve our CDMS technique, such as improvements in ion optics, ion trap design, charge sensitive preamplifier modifications, and data analysis algorithms. In particular, the challenges and issues of the CDMS ion trap will be discussed, as well as future approaches to trap design
Strategies for the synthesis of glucan building blocks and their application in manual and automated solution-phase synthesis of betaglucans by Nishad Thambanchandrika( )

2 editions published in 2015 in English and held by 11 WorldCat member libraries worldwide

Since the heterogeneity of beta-glucans isolated from natural sources makes the conclusive investigation of their biological roles arduous, structurally well-defined beta-glucans are required. An iterative approach to the synthesis of these glucans has the unique feature of incorporating any desired sugar residue onto a growing chain at any point in the synthesis to provide regio- and stereo-selectively-defined oligosaccharides in a manner readily amenable to automation. This dissertation reports the design and synthesis of a library of several linear and branched beta-glucan oligomers using an iterative fluorous tag-assisted manual and automated solution-phase method. The strategy relies on the successful design of a common intermediate to generate all desired building blocks necessary for chain extension. A [2+2] glycosylation strategy involving a disaccharide building block was successfully employed in the case of a glucan hexasaccharide for comparison to the monosaccharide building block approach
Synthesis and characterization of multivalent mimics of phosphatidylinositol-4,5-bisphosphate (pip2) micelles by Sarah Anne Webb( )

2 editions published in 2004 in English and held by 11 WorldCat member libraries worldwide

Protein-lipid molecular recognition is critical for a variety of cellular processes. Phosphoinositides are lipids that are implicated in many pathways including actin cytoskeletal remodeling, regulation of apoptosis, clathrin-mediated endocytosis and regulation of intracellular calcium. The most ubiquitous of the phosphoinositides, phosphatidylinositol-4,5-bisphosphate (PIP2) binds to numerous of known proteins and to a variety of structurally different protein domains. However, because of the fluid dynamic properties of lipid membranes and limited access to synthetic analogs, the chemical mechanisms of protein-PIP2 molecular recognition are poorly understood. Although several lines of biochemical evidence support a multivalent model for binding interactions between PIP2 and a subset of PIP2-regulated proteins, this mechanism has not been studied to date. In order to study multivalent molecular recognition between PIP2 and proteins, mimics of PIP 2 micelles containing 4, 8 and 50 copies of the lipid headgroup have been chemically synthesized and characterized. These multivalent micelle mimics were prepared using GO, G1 and G4 PAMAM dendrimers as polymeric scaffolds. PAMAM dendrimers were derivatized with 3,4-diethoxy-3-cyclobutene-1,2dione to serve as a vinylogous diamide crosslinker. Derivatization of the dendrimers to form the PIP2 micelle mimics was accomplished in aqueous media. These polymer derivatives were characterized using state-of-the-art NMR and mass spectrometry techniques. To our knowledge, this work represents the first synthesis of multivalent PIP2 analogs with this degree of substitution. These compounds are among the most highly anionic synthetic polymers that have been characterized to date
Experimental and theoretical determination of the temperature dependent rate constant for the reaction of hydroxyl radicals with some volatile organic compounds by Paul E Carey( )

2 editions published in 2015 in English and held by 11 WorldCat member libraries worldwide

Air pollution and in particular photochemical smog is still an important environmental problem due to its impact on human health. One of the main contributors is tropospheric ozone, the primary component of photochemical smog. Some of the main illnesses related to high ozone levels are respiratory infections and lung inflammation as well as exacerbating illnesses such as asthma from both acute and chronic exposure. Controlling ozone levels is challenging, because ozone is not directly emitted into the atmosphere but is a secondary pollutant produced from chemical reactions of primary emissions, both biogenic and anthropogenic. Thus control of ozone in the troposphere requires an accurate understanding of the chemistry leading to its production. The primary step in the production of tropospheric ozone is the reaction of hydroxyl radicals with volatile organic compounds. For this reason a thorough understanding of the reactions of individual volatile organic compounds with hydroxyl radicals is needed. This dissertation focuses on the reaction of the hydroxyl radical with three volatile organic compounds: allyl alcohol, 1-propanol and propionaldehyde. These reactions are studied using a discharge-flow tube technique in addition to laser induced fluorescence detection of the OH radical. In addition, theoretical computational calculations of the potential energy surface of these reactions were performed to give insight into the reaction mechanisms
Computational studies to understand the role of allostery in copper regulation in Mycobacterium tuberculosis and in the design of HPV vaccines by Abhigna Polavarapu( )

2 editions published in 2015 in English and held by 11 WorldCat member libraries worldwide

Allostery is defined as the change in the structure, function or activity of a specific site on a protein, due to the binding of a substrate or effecter on a different site of the same protein. This phenomenon has been observed and studied in two different protein systems of therapeutic importance. CsoR protein in Mycobacterium tuberculosis adopts classical allostery to regulate the concentration of Cu(I) inside the cell. Cu(I) is speculated to bind in an unusual trigonal planar geometry with two cysteines and one histidine. When CsoR is bound to copper an overall structural change (allostery) is envisioned and its affinity to DNA is lost. In the current computational exploration we focus on the binding mode of Cu(I) and identify different protonation states of copper bound cysteines. MD simulations were performed on the apo and copper bound form with a starting structure from QM/MM calculations to predict the allosteric structural transition. The dynamic properties of the capsid of the human papillomavirus (HPV) type 16 were also examined using classical molecular dynamics simulations. The allostery identified in the components of the HPV is non-classical because the mean structure of the epitope carrying loops remains unchanged as the result of allosteric effect, but the structural fluctuations are altered significantly, which in turn changes the biochemical reactivity profile of the epitopes. Exploiting this novel insight, a new vaccine design strategy is proposed, where a relatively small virus fragment is deposited on a silica nanoparticle in such a way that the fluctuations of the h4 helix are suppressed. The structural and dynamic properties of the epitope carrying loops on this hybrid nanoparticle match the characteristics of epitopes found on the full virus like particle precisely, suggesting that these nanoparticles may serve as potent, cost-effective and safe alternatives to traditionally developed vaccines
Development of mass spectrometry-based methods for natural product discovery by Ashley M Sidebottom( )

2 editions published in 2015 in English and held by 11 WorldCat member libraries worldwide

Natural products from microbial and fungal source materials spurred the age of modern medicine seventy years ago with the discovery of the antibiotic penicillin from Penicillium notatum. Natural products, also called secondary metabolites, possess a range of activities including antibacterial, antifungal, and anticancer and can aid in disease state mediation, such as the treatment of type II diabetes. Despite their historical utility, natural product discovery from bacteria has decreased over the past few decades in part due to limited availability of high-resolution spectroscopic instrumentation and a lack of comprehensive databases for known compound dereplication. To address this, we have developed a mass spectrometry-based comparative analysis method for the discovery of natural products from both well-studied and minimally-characterized but genetically promising organisms. We incorporated high accuracy multi-stage mass spectrometry, bioinformatics, and solid-phase enrichment techniques to explore the secondary metabolite content of the model organism, Streptomyces coelicolor M145, for the elucidation of novel natural products. With our approach, 15 uniquely produced amphiphilic siderophores and a putative terminal alkyne-containing natural product were discovered amidst the complex microbial matrix. As the need for new molecules continues to grow to combat current ailments, such as infection with antibiotic resistant bacterial strains, the study of natural products promises to uncover compounds that will aid in the future of therapeutics
Implementing new ligand platforms for metal-ligand multiple bond and dinitrogen chemistry by Keith Searles( )

2 editions published in 2015 in English and held by 11 WorldCat member libraries worldwide

Understanding the bonding and reactivity of highly reactive inorganic complexes requires the use of chemically robust ligand frameworks. Two new ligand platforms, a highly arylated and exceptionally bulky aryloxide, (2,6-bis(diphenylmethyl)-4- tert-butylphenol = HOAr), and an electron-rich bis-(pyrrolyl)pyridine pincer ligand, (2,6-bis(3,5-di-tert-butylpyrrolyl-2)pyridine = H2pyrr2py), have been implemented for the synthesis of novel early and late transition metal complexes respectively
Chemical probes for histidine kinase protein profiling and inhibitor discovery by Kaelyn Elizabeth Wilke( )

2 editions published in 2015 in English and held by 11 WorldCat member libraries worldwide

Adaptive bacterial signaling is largely regulated by two-component systems (TCSs). Comprised of histidine kinases (HKs) and response regulators (RRs), these phosphorylation cascades result in myriad intracellular responses that include various pathogenic mechanisms. Despite their abundance in Gram-negative, Gram-positive, and Mycobacterial organisms, little is known about global TCS regulation. Most studies focus on the response of one HK-RR pair to various stimuli primarily because of the lack of tools to enable global analysis of TCS activity. We are working to address this deficiency by generation of probes to profile HK autophosphorylation activity. Significantly, we have identified the first non-radioactive activity-based probe for HK signaling, BODIPY-FL-ATPgammaS, a fluorescent adenosine triphosphate (ATP)-based probe that exploits thiophosphorylation to afford greater stability and thus more facile detection of protein activation. This and other ATPgammaS-based probes are in development for the profiling of HK activity from bacterial proteomes. In addition to understanding system-wide HK regulation, we also seek to inhibit TCS signaling networks and thereby severely attenuate bacteria's ability to cause infection. To do this, we have targeted the highly conserved ATP-binding domain present across the HK superfamily. Revisiting previously reported nonspecific inhibitors, we repurposed a common feature into a guanidine-based fragment that anchors to the ATP-binding domain through interaction with an invariant residue. Additionally, a synthesized ADP-BODIPY probe enabled us to also pursue new inhibitor scaffolds through the optimization and execution of a high-throughput screen of ~75,000 diverse small molecules and natural product extracts. As a result, nine lead compounds have been identified for deactivation of multiple HKs. Scaffolds identified in these studies contribute to the foundation for HK inhibitor development, supporting a new class of antibiotics with a novel mechanism of action. Together, our chemical probes will continue to advance our current understanding of global HK regulation and inhibition
Probing supramolecular surface assemblies : ion binding, self-association, and electric field perturbations by Brandon E Hirsch( )

2 editions published in 2015 in English and held by 11 WorldCat member libraries worldwide

Self-assembly has emerged as a versatile strategy to engineer complex, organic nanostructures at surfaces with high fidelity. However, most synthetic assemblies lack the adaptive functionality that is common in their biological counterparts. We demonstrate the formation of several stimuli-responsive surface assemblies using synthetically programmed components with known host-guest recognition properties. Anionic guests are used to drive reversible phase switching, template bilayer growth, and regulate multilayer growth. Scanning tunneling microscopy provides submolecular resolution of individual anion binding and self-association events. The charged nature of the guests allows predictable control of phase switching using the electric field from the scanning tip. Overall, this work highlights the use of molecular design to develop functional components that are organized hierarchically on a surface to yield adaptive properties
 
moreShow More Titles
fewerShow Fewer Titles
Audience Level
0
Audience Level
1
  General Special  
Audience level: 0.00 (from 0.00 for Developmen ... to 0.00 for Developmen ...)

Alternative Names

controlled identityIndiana University, Bloomington

controlled identityIndiana University. Department of Chemistry

Indiana University Bloomington Chemical Department

Indiana University, Bloomington. Chemistry Department

Indiana University, Bloomington Chemistry Dept

Indiana University, Bloomington. Dept. of Chemistry

Languages
English (36)