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Illuminating Biology With Membrane Penetrating Sulfonate Delivery Scaffolds And Near-Infrared Azasiline Fluorophores, Adam Choi 2018 University of Massachusetts Medical School

Illuminating Biology With Membrane Penetrating Sulfonate Delivery Scaffolds And Near-Infrared Azasiline Fluorophores, Adam Choi

GSBS Dissertations and Theses

Near-infrared (NIR) light, with wavelengths of 650 to 900 nanometers, effectively penetrates tissues. The high signal to noise ratio and low phototoxicity of NIR light makes this wavelength range ideal for deep tissue imaging. However, current NIR fluorophores are generally large hydrophobic molecules that are prone to aggregation. Sulfonation can enhance aqueous solubility, but their anionic nature prevents membrane diffusion, and thus, restricts the applications of sulfonated molecules to in vitro or fixed cells.

The repertoire of commercially available sulfonated NIR probes is mostly limited cyanines, which have low photostability. Moreover, larger cyanines require multiple sulfonates to maintain aqueous solubility ...


Enhancement Of Triplet-Sensitized Upconversion In Rigid Polymers Via Singlet Exciton Sink Approach, Steponas Raišys, Saulius Juršėnas, Yoan C. Simon, Christoph Weder, Karolis Kazlauskas 2018 Vilnius University

Enhancement Of Triplet-Sensitized Upconversion In Rigid Polymers Via Singlet Exciton Sink Approach, Steponas Raišys, Saulius Juršėnas, Yoan C. Simon, Christoph Weder, Karolis Kazlauskas

Faculty Publications

To increase the practical usefulness of solid-state sensitized upconversion (UC) materials as components of solar energy harvesting systems, it is important to identify and suppress loss mechanisms, and increase the UC quantum yield (ΦUC). Here we focus on a benchmark UC system consisting of the emitter 9,10-diphenylanthracene (DPA) and the sensitizer platinum octaethylporphyrin (PtOEP) in a rigid poly(methyl methacrylate) (PMMA) matrix, and show that one of the major losses originates from Förster resonant energy transfer (FRET) from DPA back to PtOEP. Even though DPA emission lies within the PtOEP transparency window, the quantitative assessment of singlet exciton ...


Archean Phosphorus Liberation Induced By Iron Redox Geochemistry, Barry Herschy, Sae Jung Chang, Ruth Blake, Aivo Lepland, Heather Abbott-Lyon, Jacqueline Sampson, Zachary Atlas, Terence P. Kee, Matthew A. Pasek 2018 University of South Florida

Archean Phosphorus Liberation Induced By Iron Redox Geochemistry, Barry Herschy, Sae Jung Chang, Ruth Blake, Aivo Lepland, Heather Abbott-Lyon, Jacqueline Sampson, Zachary Atlas, Terence P. Kee, Matthew A. Pasek

Faculty Publications

The element phosphorus (P) is central to ecosystem growth and is proposed to be a limiting nutrient for life. The Archean ocean may have been strongly phosphorus-limited due to the selective binding of phosphate to iron oxyhydroxide. Here we report a new route to solubilizing phosphorus in the ancient oceans: reduction of phosphate to phosphite by iron(II) at low (<200 >°C) diagenetic temperatures. Reduction of phosphate to phosphite was likely widespread in the Archean, as the reaction occurs rapidly and is demonstrated from thermochemical modeling, experimental analogs, and detection of phosphite in early Archean rocks. We further demonstrate that the ...


Crystal Structure Of A Homoleptic Zinc(Ii) Complex Based On Bis­(3,5-Diiso­Propyl­Pyrazol-1-Yl)Acetate, Josiah G. Elsberg, Nicholas G. Spiropulos, Adam C. Colson, Eric C. Brown 2018 Boise State University

Crystal Structure Of A Homoleptic Zinc(Ii) Complex Based On Bis­(3,5-Diiso­Propyl­Pyrazol-1-Yl)Acetate, Josiah G. Elsberg, Nicholas G. Spiropulos, Adam C. Colson, Eric C. Brown

Chemistry Faculty Publications and Presentations

Deprotonation of the methyl­ene group in bis­(3,5-diiso­propyl­pyrazol-1-yl)methane with nBuLi and reaction with carbon dioxide yields lithium bis­(3,5-diiso­propyl­pyrazol-1-yl)acetate (1). Treatment of 1 with ZnCl2 results in the com­pound bis­[bis­(3,5-diiso­propyl­pyrazol-1-yl)acetato]­zinc(II), [Zn(C20H31N4O2)2] (2), whose structure has monoclinic (P21/c) symmetry. The ZnII ion resides on an inversion center and is coordinated by two bis­(3,5-diiso­propyl­pyrazol-1-yl)acetate (bdippza) ligands. Each ligand facially coordinates the zinc center via ...


Nmr Characterizations Of Candidate Battery Electrolytes, Stephen A. Munoz 2018 The Graduate Center, City University of New York

Nmr Characterizations Of Candidate Battery Electrolytes, Stephen A. Munoz

All Dissertations, Theses, and Capstone Projects

Enormous strides have been made in next-generation power sources to build a more sustainable society. Energy storage has become a limiting factor in our progress, and there are huge environmental and financial incentives to find the next step forward in battery technology. This work discusses NMR methods for characterizing materials for use in battery application, with a special focus on relaxometry and diffusometry. Examples are provided of various recent investigations involving novel candidate electrolyte materials with different collaborators. Works discussed in this thesis include: the characterization of a new disruptive solid polymer electrolyte technology, investigations of the dynamics of super ...


Synthesis And Evaluation Of Densely-Functionalized Troponoids, Danielle R. Hirsch 2018 The Graduate Center, City University of New York

Synthesis And Evaluation Of Densely-Functionalized Troponoids, Danielle R. Hirsch

All Dissertations, Theses, and Capstone Projects

Herein, we document our efforts to expand the scope of troponoid synthetic methodology towards densely-substituted scaffolds. This body of work has focused primarily on an oxidopyrylium cycloaddition/ring-opening strategy for the synthesis and biochemical evaluation of troponoids for assistance in a variety of medicinal chemistry studies. In Chapter 1, we outline the use of this synthetic strategy in the profiling of a library of synthetic αHTs against an aminoglycoside antibiotic resistance enzyme known as aminoglycoside-2’’-O-nucleotidyltransferase [ANT(2’’)-Ia]. Enzymatic mechanistic insights have been gleaned from an assessment of troponoid/antibiotic synergistic potential. In particular, two synthetic constructs were identified ...


Fundamental Chemistry Related To The Separations And Coordination Of Actinium-225, Thorium-227, And Technetium-99, Jasmine L. Hatcher 2018 The Graduate Center, City University of New York

Fundamental Chemistry Related To The Separations And Coordination Of Actinium-225, Thorium-227, And Technetium-99, Jasmine L. Hatcher

All Dissertations, Theses, and Capstone Projects

This work explores the fundamental chemistry of actinium, thorium, and technetium in an effort to develop methodologies which help to address complications specific to each of these elements. Developing fundamental knowledge in inorganic chemistry has the power to meaningfully address a number of real world problems. By using simple systems and experiments like following an electron or changing the solvent system, we are able to gain invaluable information which can be used to address major issues.

Actinium-225 (t½: 9.92 d) is an alpha-emitting radionuclide with nuclear properties well suited for alpha therapy of malignant tumors. The present global ...


Characterization And Quantification Of Covalent Modification Of Proteins Using Mass Spectrometry, Pratikkumar N. Rathod 2018 The Graduate Center, City University of New York

Characterization And Quantification Of Covalent Modification Of Proteins Using Mass Spectrometry, Pratikkumar N. Rathod

All Dissertations, Theses, and Capstone Projects

Identification and characterization of various post-translational modifications of protein is a key to understanding many unknown cellular processes. In the last few decades, mass spectrometry has evolved as an essential and effective analytical tool for qualitative and quantitative analysis of proteins. In this research, we have developed a novel MALDI-MS2 based quantification method for Desmosine and Isodesmosine, which served as cross-linking amino acids of elastin, in order to measure the elastin degradation in the body. This is the first quantification method that not only illustrates the potential of MALDI-Ion Trap MS2, but also improvement over the current LC-MS ...


Nuclear Magnetic Resonance Studies Of Imidazolium-Based Ionic Liquids And Garnet-Type Li7la3zr2o12, Shen Lai 2018 The Graduate Center, City University of New York

Nuclear Magnetic Resonance Studies Of Imidazolium-Based Ionic Liquids And Garnet-Type Li7la3zr2o12, Shen Lai

All Dissertations, Theses, and Capstone Projects

Advancements in electrochemical energy storage materials are critical in the development and utilization of renewable energy technologies. These advancements involve obtaining a better understanding of electrochemical mechanisms and properties through scientific research towards an improved energy storage technology. Nuclear magnetic resonance (NMR), is a sensitive and selective method to probe particle dynamics (magnetic relaxation, diffusometry, etc.) and material structures (spectroscopy) down to the atomic level. In this work, several NMR techniques are employed to study imidazolium-based ionic liquids and garnet-type inorganic materials. These are being studied due to their potential use as safer alternatives to organic solvent-based electrolytes in lithium-ion ...


A Stereospecific Pd-Catalyzed Suzuki Cross-Coupling Reaction And A Statistical Study Of The Ligand's Role In Stereoselection, Shibin Zhao 2018 The Graduate Center, City University of New York

A Stereospecific Pd-Catalyzed Suzuki Cross-Coupling Reaction And A Statistical Study Of The Ligand's Role In Stereoselection, Shibin Zhao

All Dissertations, Theses, and Capstone Projects

The development of palladium-catalyzed carbon-carbon cross-coupling reactions has profoundly influenced the manner through which we approach the synthesis of complex organic molecules. Among established cross-coupling reactions, which include Kumada, Negishi, and Stille reactions, the Suzuki cross-coupling reaction exhibits particularly wide functional group compatibility, while employing non-toxic, air-stable organoboron nucleophiles. Conventional studies of Pd-catalyzed Suzuki cross-coupling reactions have focused on C(sp2)-C(sp2) cross-coupling reactions, which result in the formation of planar products. Conceptually, the use of C(sp3) (secondary) nucleophiles would enable the reliable manipulation of organic molecules in three dimensions. However, this process has not ...


Flexible And Versatile Soft Templates For Mesoporous Silicas And Organosilicas Based On Pluronic Block Copolymer Surfactants And Their Mixtures, George Farid 2018 The Graduate Center, City University of New York

Flexible And Versatile Soft Templates For Mesoporous Silicas And Organosilicas Based On Pluronic Block Copolymer Surfactants And Their Mixtures, George Farid

All Dissertations, Theses, and Capstone Projects

In this dissertation, the work will be discussed that was focused on the synthesis of consolidated periodic mesoporous materials such as 2-D hexgonal ordered mesoporous silicas (SBA-15) as well as single-micelle-templated silica and organosilica nanotubes and nanospheres using triblock copolymer surfactants and their mixtures in the presence of a swelling agent. The introductory section, Chapter 1, will address the current state of the tunability of single-micelle-templated silica and organosilica nanotubes and will compare it with the work presented in this dissertation on the use of a dual-surfactant templating systems. Chapter 2 of the dissertation discusses transmission electron microscopy characterization of ...


Nascent O2 (A1ΔG, V = 0, 1) Rotational Distributions From The Photodissociation Of Jet‐Cooled O3 In The Hartley Band, Michelle L. Warter, Carolyn E. Gunthardt, Wei Wei, George McBane, Simon W. North 2018 Texas A & M University - College Station

Nascent O2 (A1ΔG, V = 0, 1) Rotational Distributions From The Photodissociation Of Jet‐Cooled O3 In The Hartley Band, Michelle L. Warter, Carolyn E. Gunthardt, Wei Wei, George Mcbane, Simon W. North

Peer Reviewed Articles

We report rotational distributions for the O2 (a 1Δg) fragment from photodissociation of jet‐cooled O3 at 248, 266, and 282 nm. The rotational distributions show a population alternation that favors the even states, as previously reported for a 300 K sample by Valentini et al. (J. Chem. Phys. 86, 6745 (1987)). The alternation from the jet‐cooled precursor is much stronger than that observed by Valentini et al., and in contrast to their observations does not depend strongly on O2 (a 1Δg) vibrational state or photolysis wavelength. The odd/even alternation diminishes ...


Native V. Californicum Alkaloid Combinations Induce Differential Inhibition Of Sonic Hedgehog Signaling, Matthew W. Turner, Roberto Cruz, Jordan Elwell, John French, Jared Mattos, Owen M. McDougal 2018 Boise State University

Native V. Californicum Alkaloid Combinations Induce Differential Inhibition Of Sonic Hedgehog Signaling, Matthew W. Turner, Roberto Cruz, Jordan Elwell, John French, Jared Mattos, Owen M. Mcdougal

Chemistry Faculty Publications and Presentations

Veratrum californicum is a rich source of steroidal alkaloids such as cyclopamine, a known inhibitor of the Hedgehog (Hh) signaling pathway. Here we provide a detailed analysis of the alkaloid composition of V. californicum by plant part through quantitative analysis of cyclopamine, veratramine, muldamine and isorubijervine in the leaf, stem and root/rhizome of the plant. To determine whether additional alkaloids in the extracts contribute to Hh signaling inhibition, the concentrations of these four alkaloids present in extracts were replicated using commercially available standards, followed by comparison of extracts to alkaloid standard mixtures for inhibition of Hh signaling using Shh-Light ...


Rational Design Of Superhydrophilic/Superoleophobic Surfaces For Oil-Water Separation Via Thiol-Acrylate Photopolymerization, Li Xiong, Wei Guo, Benjamin M. Alameda, Reese Sloan, William D. Walker, Derek L. Patton 2018 University of Southern Mississippi

Rational Design Of Superhydrophilic/Superoleophobic Surfaces For Oil-Water Separation Via Thiol-Acrylate Photopolymerization, Li Xiong, Wei Guo, Benjamin M. Alameda, Reese Sloan, William D. Walker, Derek L. Patton

Faculty Publications

We report a simple, rapid, and scalable strategy to fabricate surfaces exhibiting in-air superoleophobic/superhydrophilic wetting via sequential spray deposition and photopolymerization of nanoparticle-laden thiol–acrylate resins comprising both hydrophilic and oleophobic chemical constituents. The combination of spray deposition with nanoparticles provides hierarchical surface morphologies with both micro- and nanoscale roughness. Mapping the wetting behavior as a function of resin composition using high- and low-surface-tension liquid probes enabled facile identification of coatings that exhibit a range of wetting behavior, including superhydrophilic/superoleophilic, superhydrophobic/superoleophobic, and in-air superhydrophilic/superoleophobic wetting. In-air superhydrophilic/superoleophobic wetting was realized by a dynamic rearrangement of ...


Exploring The Chemistry Of Asymmetric Phosphines & Phosphinidene Sulfides, Taylor E. Pritchard 2018 The University of Western Ontario

Exploring The Chemistry Of Asymmetric Phosphines & Phosphinidene Sulfides, Taylor E. Pritchard

Electronic Thesis and Dissertation Repository

The field of low-coordinate main group chemistry has seen huge development in the last 30 years, with novel compounds that demonstrate unique structures and reactivity. Isolation of these species has relied on thoughtfully designed substituents normally containing substructure steric bulk. The area of phosphinidene chalcogenide isolation and transfer remains poorly understood by comparison. In this context, the major focus of thesis was on the development of a room-temperature method for the transfer of RP=S moieties with and without sterically demanding substituents. The preparation and complete characterization of new asymmetric phosphines with m-terphenyl ligands was also reported. In Chapter ...


Stylolites Cathodoluminescence Under Cross Polarized Light, Katherine Dvorak 2018 Western Michigan University

Stylolites Cathodoluminescence Under Cross Polarized Light, Katherine Dvorak

The Hilltop Review

Devil's Gate limestone under cathodoluminescence. Bright yellow and orange areas are calcite and the bright blue indicates trace minerals along the solution seam. Trace minerals left in the seam are heavy metals and other silicate minerals.


High-Dimensional Isotope Relationships, Yuyang He 2018 Louisiana State University

High-Dimensional Isotope Relationships, Yuyang He

LSU Doctoral Dissertations

High-dimensional isotope relationships describes the relationships of two or more element or position-specific (PS) elements in the same molecule or ion. It provides us more powerful tools to study reaction mechanisms and dynamics. Chapter 1 is about dual or multiple stable isotope relationship on δ-δ (or δ'-δ') space. While temporal data sampled from a closed-system can be treated by a Rayleigh Distillation Model (RDM), spatial data should be treated by a Reaction-Transport Model (RTM). Here we compare the results of a closed-system RDM to a RTM for systems with diffusional mass transfer by simulating the trajectories on nitrate's ...


Modulating Viscoelasticity, Stiffness, And Degradation Of Synthetic Cellular Niches Via Stoichiometric Tuning Of Covalent Versus Dynamic Noncovalent Cross-Linking, Yu Tan, Henry Huang, David C. Ayers, Jie Song 2018 University of Massachusetts Medical School

Modulating Viscoelasticity, Stiffness, And Degradation Of Synthetic Cellular Niches Via Stoichiometric Tuning Of Covalent Versus Dynamic Noncovalent Cross-Linking, Yu Tan, Henry Huang, David C. Ayers, Jie Song

Open Access Articles

Viscoelasticity, stiffness, and degradation of tissue matrices regulate cell behavior, yet predictive synergistic tuning of these properties in synthetic cellular niches remains elusive. We hypothesize that reversible physical cross-linking can be quantitatively introduced to synthetic hydrogels to accelerate stress relaxation and enhance network stiffness, while strategic placement of isolated labile linkages near cross-linking sites can predict hydrogel degradation, both of which are essential for creating adaptive cellular niches. To test these hypotheses, chondrocytes were encapsulated in hydrogels formed by biorthogonal covalent and noncovalent physical cross-linking of a pair of hydrophilic building blocks. The stiffer and more viscoelastic hydrogels with DBCO-DBCO ...


Pre- And Post-Research Group Selection: Evolving Roles For Chemistry Librarians, Sarah Jeong, Kiyomi D. Deards 2018 Wake Forest University

Pre- And Post-Research Group Selection: Evolving Roles For Chemistry Librarians, Sarah Jeong, Kiyomi D. Deards

Library Conference Presentations and Speeches

Librarian consultations with research groups, flipped classroom exercises, active learning, and Just-In-Time instruction sessions are increasing at public and private doctoral granting universities at a time when many library staffs are shrinking. As the needs and points of contact with graduate students evolve it will be critical for the depth of knowledge and resources of chemistry librarians to be understood and shared both in-person and on-demand online. This presentation will outline the strategies used to meet the evolving needs of chemistry graduate students as they move from pre-research group selection into established research groups.


Determination Of Polar Solvents By Static Headspace Extraction – Gas Chromatography (She-Gc), Michael Sithersingh 2018 Seton Hall University

Determination Of Polar Solvents By Static Headspace Extraction – Gas Chromatography (She-Gc), Michael Sithersingh

Seton Hall University Dissertations and Theses (ETDs)

ABSTRACT

The term “headspace” is defined as the vapor that forms above or around a liquid or solid sample in a closed container. Usually, the vapor is above the liquid or solid at the top of the container, hence the term headspace. Headspace sampling is a method for separating volatile materials that may be extracted from a more solid sample matrix and then analyzed using gas chromatography. Headspace extraction refers to the collection and analysis of the vapor phase in the container. The Static Headspace Extraction – Gas Chromatography (SHE-GC) technique has been used since the early days of Gas Chromatography ...


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