Physical Sciences and Mathematics Commons^™

Characterization Of Landfill Leachate For Enhanced Metal Recovery, Hanna Fulford, Amisha Shah, Inez Hua, Nadezhda Zyaykina, Lori Hoagland, Alejandro Rodriguez Sanchez, Umut Bicim

Discovery Undergraduate Interdisciplinary Research Internship

Landfills contain a trove of valuable materials, such as critical, precious, and rare earth metals, that are integral to the United State’s economy and national security. The leachate that filters through landfills picks up these materials, which allows for the possibility of recovery. For this research, samples will be analyzed from landfills throughout the Midwestern United States to provide a baseline on water quality constituents, elements present, and microbial activity. Preliminary data for this study was acquired by analyzing samples of landfill leachate from a landfill in northern Indiana. pH readings indicate that the leachate is slightly basic. It also …

Thienoisatin Oligomers As N-Type Molecular Semiconductors, Natalie M. Kadlubowski, Xuyi Luo, Jianguo Mei

The Summer Undergraduate Research Fellowship (SURF) Symposium

Organic field effect transistors (OFETs) offer many advantages compared to traditional inorganic transistors, such as flexibility and solution processability. In this study we design and synthesize two thienoisatin-based organic semiconducting small molecules, then investigate their electronic properties in n-type OFETs. To introduce n-type charge transport, electron-withdrawing dicarbonitrile moieties were installed on thienoisoindigo and bis-thienoisatin molecules, which led to a quinoidal conjugation on thienoisoindigo, while maintaining an aromatic conjugation on the bis-thienoisatin. Following the syntheses, the molecules were characterized to determine highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels via cyclic voltammetry, as well as any potential …

Examining The Effects Of Amino And Thiolate Ligands On The Reactivity And Selectivity Of Palladium On Carbon In Hydrogenation Reactions, Eric Liu, Christina Li

The Summer Undergraduate Research Fellowship (SURF) Symposium

Heterogeneous catalysts are used widely by chemical and energy industries because they show high reactivity but often suffer from lack of selectivity. On the other hand, ligands are commonly used in homogeneous catalysts to control the reactivity and selectivity; however, the effects of the ligands on the steric and electronic properties of heterogeneous catalysts are less understood. We examine the effects of four different ligands: 1-adamantanethiol, 1-adamantylamine, 1-dodecanethiol, and 1-dodecylamine, for the commercial hydrogenation catalyst palladium on carbon. Hydrogenation reactions are used as a screening tool to see the behavior that the different catalysts exhibit in the presence of unsaturated …

Synthesis Of Healable Organic Semiconductor Through Dioxaborolane Bond, Junchen Liu, William W. Mcnutt, Jianguo Mei

The Summer Undergraduate Research Fellowship (SURF) Symposium

The field of organic semiconductors have gained enormous attention the past few decades. Organic materials offer numerous advantages over their inorganic counterparts. Recently a number of works have demonstrated organic semiconductors with healable properties. We aim to investigate the healable ability of an organic semiconductor by mimicking a vitrimer system through the reversible dioxaborolane bond. Vitrimers are polymers with reversible crosslink system. It has been reported that the use of the borane-oxygen bond as the crosslink showed good mechanical performance. The electrical properties will be inspected for the vitrimer-like polymer. In this report we describe a Diketopyrrolopyrrole base polymer incorporating …

Synthetic Studies Of Heparan Derivatives: Glycosyl Couplings And Post-Glycosylative Modifications, Hari Raj Khatri

Open Access Dissertations

Heparan sulfate (HS) and closely related heparin are comprised of alternating units of D-glucosamine and either D-glucuronic acid (D-GluA) or L-iduronic acid (L-IdoA), and support variable degrees of sulfation which can interact with a large number of proteins with diverse biological functions. HS oligosaccharides can be constructed from readily accessible D-GlcN and D-GlcA derivatives, but the inclusion of L-IdoA is less straightforward. To address this, our laboratory has developed alternative synthetic strategies for HS-like oligosaccharides to incorporate either D-GlcA or L-IdoA in a synthetically efficient manner by nucleophilic ring opening of 4-epoxypyranosides, which can be made from readily available D-hexoses …

Analysis Of The Fabrication Conditions In Organic Field-Effect Transistors, Rachel M. Rahn, Yan Zhao, Jianguo Mei

The Summer Undergraduate Research Fellowship (SURF) Symposium

Polymer-based organic field-effect transistors have raised substantial awareness because they enable low-cost, solution processing techniques, and have the potential to be implemented in flexible, disposable organic electronic devices. The performance of these devices is highly dependent on the processing conditions, as well as the intrinsic properties of the polymer. Processing conditions play an important role in semiconductor film formation and device performance. These factors may provide an important link between structure and performance. In this study, an empirical analysis tool, Process Scout, was applied to assess processing factors such as polymer concentration and silicon modification. This sanctioned the creation of …

Development Of A Scalable Synthesis Of Hp-Β-Cd Pluronic Polyrotaxanes, Joseph L. Skulsky, Elizabeth A. Slepko, Bradley P. Loren, David H. Thompson

The Summer Undergraduate Research Fellowship (SURF) Symposium

Polyrotaxanes are polymers that have macrocycles threaded onto them, analogous to beads threaded onto a string. These materials are used for a variety of different biomedical applications.^1-3 The Thompson group has been developing 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) polyrotaxanes as therapeutics for the treatment of Niemann-Pick Type C (NPC) disease. NPC is a debilitating genetic disorder where cholesterol accumulates in the lysosomes of cells.⁴ Developing a scalable process is crucial for the advancement of these materials as NPC therapeutics. The goal of this project is to optimize the only protocol for the synthesis of HP-β-CD/Pluronic polyrotaxanes in order to develop a …

Studies Of Arctic Halogen Chemistry From The Snowpack To The Gas Phase, Kyle D Custard

Open Access Dissertations

The temporary depletion of both tropospheric ozone and gaseous mercury during the Arctic springtime has been a focus of active research over the past several decades. Both of these phenomena have been linked to chemical reactions with halogen radicals. In particular, bromine atoms have been shown to act as the primary driver for these chemical depletions, although both chlorine and iodine atoms also contribute. Molecular bromine, along with its oxidation products, have been well studied in the Arctic, yet chlorine has not. Chlorine is known to impact the local oxidation capacity via its high reactivity with volatile organic compounds. Despite …

A Bracketing Method For Proton Affinity Measurements Of Dehydro-And Didehydropyridines, Guannan Li

Open Access Theses

Proton affinity (PA) is a fundamental property that is related to the structure and reactivity of a molecule. Currently, very few experimental PA values are available for organic radicals and none for biradicals. Equilibrium methods cannot be used for these measurements. The traditional bracketing method is based on monitoring reactions of different reference bases with known proton affinities with the protonated analyte for the occurrence of exothermic proton transfer to determine the upper and lower limits of proton affinity. However, the energy deposited into the precursor ions upon CAD when forming protonated radicals may cause endothermic proton transfer reactions occur …

Non-Covalent Affinity Materials For Protein Structure Determination Via Single Particle Reconstruction Analysis Cryo-Electron Microscopy, Minji Ha

Open Access Theses

Single particle analysis (SPA) by cryogenic electron microscopy (Cryo-EM) is one of the powerful tools for determining biological macromolecule structure, particularly when combined with computational methods or X-ray crystallography. However, the SPA is challenged by sample processing efficiency. In this work, polyrotaxane (PRTx) was designed and synthesized such that laterally and rotationally mobile lysine nitrolicacetic acid (Lys-NTA) modified α-cyclodextrins (α-CD) were threaded onto a polyethylene glycol (PEG) core. Polyrotaxanes threaded with amine modified α-CD were also designed and synthesized for stoichiometric control of His-tagged protein capture by PRTx. For higher efficiency of single particle analysis along a single strand of …

Structure-Activity Relationships For The Water-Gas Shift Reaction Over Supported Metal Catalysts, Kaiwalya D. Sabnis

Open Access Dissertations

The Water-Gas Shift (WGS) reaction (CO + H₂O → CO₂ + H₂) is an important chemical process for industrial hydrogen production. The overall goal of this project is to use kinetic experiments and in situ characterization techniques in tandem, in order to derive structure-activity relationships for various catalytic systems. These relationships facilitate the rational catalyst design by identification of catalyst descriptors. In order to establish such relationships, various studies were undertaken, such as (i) effect of transition admetals on the WGS catalysis by molybdenum carbide (ii) effect of residual oxygen content on the performance of …

Development Of Novel Strategies To Combat Multidrug Resistance Mediated By Efflux Transporters And Intracellular Bacteria, Jerrin Kuriakose

Open Access Dissertations

Multidrug resistance (MDR) is the condition where cancer cells or microorganisms cease to respond to multiple drugs. MDR conferred by efflux transporters, that deprive the bioavailability of drugs at their site of action, are a threat to cancer and malarial chemotherapy. Specifically, the mammalian ABC transporter Pglycoprotein (P-gp) has undermined many drugs in treatment of cancer and other disease states. Mutations in the parasitic transporter Plasmodium falciparum chloroquine resistance transporter (PfCRT) have given rise to strains unsusceptible to the aminoquionoline family of antimalarials. Using the very drug substrates, we have developed bivalent inhibitors of P-gp. Here, click chemistry has been …

High-Purity Gallium Analysis By Inductively Coupled Plasma Mass Spectrometry, Kyungjean Min

Open Access Theses

The mobility of Two-dimensional Electron Gas in AlGaAs/GaAs heterostructures that are grown in the Molecular Beam Epitaxy (MBE) can be increased by purification of the gallium used to grow the films. To attain 200 million cm2/Vs mobility, the impurity concentration of gallium should be reduced to below 1 ppb. The commercial 7N (99.99999%) gallium with 100 ppb total impurity is currently used in the MBE at Purdue University and is being purified by zone refining. To evaluate the commercial 7N gallium and establish the methodology for the impurity measurement after zone refining, germanium, iron, and zinc in 6N and 7N …

Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, Holly Chan

Open Access Theses

The design and synthesis of electrically-conductive macromolecules can lead to significant improvements in the performance of polymer-based energy conversion devices (e.g., thermoelectric devices). For these organic electronic devices, conjugated polymers have dominated the area of conductive polymers; however, these materials are usually synthesized using conditions that lead to poorly-defined polymers. Furthermore, in these increasingly-standard polymers, the charge transport ability of the polymer thin films is largely affected by the degree of crystallinity, which is a difficult property to control in a reproducible fashion. Therefore, we seek to explore a new class of amorphous, non-conjugated polymers containing a stable radical …

Investigating Intermolecular Interactions In Crystalline Aspirin Using Cdft, Nicholas Turner, Tonglei Li, Mingtao Zhang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Drugs today are widely administered in their crystalline form, namely via tablets and capsules. The crystal structure of a drug molecule affects important drug qualities such as solubility, bioavailability, shelf life, and compaction properties. In order to form a basis for crystal structure prediction, it is necessary to first understand how intermolecular interactions cause molecules to pack in certain ways. Being able to predict and perhaps even control a drug molecule’s crystal structure will lead to the development of higher quality drugs that perform more consistently. Scientists and engineers do not fully understand the reasons for a molecule assuming a …

Continued Progress Towards Efficient Syntheses Of Cephalostatin North 1 Analogs, Daniel Preston Jamieson

Open Access Dissertations

Jamieson, Daniel P. Ph.D., Purdue University, December 2013. Continued Progress Towards Efficient Syntheses of Cephalostatin North 1 Analogs. Major Professor: PhilipL. Fuchs.

The cephalostatins and ritterazines represent an intriguing class of marine natural products in both structure and biological activity, and the progress towards the synthesis of high valued analogs with a focus on process orientated methodology is described herein. Included in the pages to follow, is the further advancement of the `Red-Ox' strategy toward the highly efficient synthesis of 25-epi-4,15-dihydro-North 1, Chapter 2. A short review focusing on the earlier efforts toward the main synthetic challenges of North 1 …

Synthesis Of Novel Isoprenoid Diphosphate Analogs As Chemical Tools To Investigate Protein Geranylgeranylation, Kayla Jo Temple

Open Access Dissertations

Many proteins require prenylation in order to be biologically functional. Some such proteins include the small Ras and Rho GTPase superfamilies, nuclear lamins A and B, and the kinesin motor proteins CENP-E and F. Prenyltransferase (PTase) inhibition is currently being explored as a possible treatment not only for cancer but for a wide variety of other diseases.

Clinical studies revealed that the effectiveness of farnesyltransferase inhibitors (FTIs) to treat Ras-dependent tumors is determined by which isoform of Ras is overactive. Unfortunately the majority of Ras-dependent tumors have a mutation in either the N- or K-Ras isoforms; both of these isoforms …

Fluorous- Phase Synthesis Of Heparan Sulfate Disaccharides & Low-Molecular Weight Additives For Enhancing The Performance Of Lithium-Ion Batteries., Matthew Daniel Casselman

Open Access Dissertations

Heparan sulfate is a complex cell-surface proteoglycan that serves many important roles in biology, such as growth and development, immune response and pathogenesis. Heparan sulfate is structurally heterogeneous due to the variable post- glycosylation modifications, particularly the generation of diverse sets of sulfate esters (sulfoforms) for any given disaccharide unit. In order to establish useful relationships between heparan sulfate structure and biological activity, a set of well-defined sulfoforms is necessary to support binding affinity screening. In this thesis, we describe the generation of diverse sulfoforms from heparan disaccharides using a fluorous tag to facilitate purification of highly charged intermediates, and …

Osmium Catalyzed Dihydroxylation And Oxidative Cleavage Of Vinyl Sulfone And Elucidation Of The Vinylsulfone Polypropionate Methodology For The Synthesis Of The C32 Des-Methyl C28-C34 Actin Binding Tail Of Aplyronine A, Thomas Paul Bobinski

Open Access Dissertations

A general methodology for the generation of dipropionate functionalities using cyclic 7-membered vinylsulfones has been devised for the purpose of synthesizing polyketide natural products such as aplyronine A. Final oxidative cleavage via ozonolysis has been shown to be difficult providing variable yields. Furthermore, elegant synthesis of the C28-C34 segment of the aplyronine A actin binding tail has proved elusive. Utilization of OsO4 and catalytic citric acid has led to a methodology whereby harsh ozonolysis procedures can be mostly avoided. A reengineering of the vinylsulfone polypropionate methodology in conjunction with osmylation has been found to provide the actin binding tail under …