Chemistry Commons^™

Protein Free Energy Landscapes Remodeled By Ligand Binding, Troy C. Messina, David Talaga

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Glucose/galactose binding protein (GGBP) functions in two different larger systems of proteins used by enteric bacteria for molecular recognition and signaling. Here we report on the thermodynamics of conformational equilibrium distributions of GGBP. Three fluorescence components appear at zero glucose concentration and systematically transition to three components at high glucose concentration. Fluorescence anisotropy correlations, fluorescent lifetimes, thermodynamics, computational structure minimization, and literature work were used to assign the three components as open, closed, and twisted conformations of the protein. The existence of three states at all glucose concentrations indicates that the protein continuously fluctuates about its conformational state space via …

Surge Of Green: A Sustainable Approach To Conductive Polymers, Bethany Masten

Undergraduate Review

No abstract provided.

Antibacterial Fluoromicas: A Novel Delivery Medium, Bekir Dizman, Jonathan C. Badger, Mohamed O. Elasri, Lon J. Mathias

Faculty Publications

Antibacterial fluoromicas were prepared by ion-exchanging fluoromicas with different antibacterial agents including various quaternary ammonium compounds, AgNO₃, and norfloxacin. Antibacterial activities of the ion-exchanged fluoromicas were determined against Staphylococcus aureus and Escherichia coli. Minimum inhibitory concentration (MIC) and zone of inhibition (ZOI) tests were performed to determine both antibacterial effectiveness and mode of action associated with the fluoromicas. All treated fluoromicas showed excellent antibacterial activities against both types of bacteria. The antibacterial activities of treated fluoromicas were found to be either better than or the same as those of neat antibacterial agents. The repeated antibacterial activity tests demonstrated …

Synthesis Towards Novel Boron Modified Polypeptides As Potential Hiv-1 Protease Inhibitors, Tajinder Heer

Undergraduate Honors Theses

Although current HIV-1 protease inhibitors on the market show high specificity, a number of side effects can result from their administration. Furthermore, quick drug resistance is developed due to mutations of the protease. Consequently, there exists a great and urgent need for the development of a novel HIV-1 protease inhibitors that have less toxicity, greater bioavailability, and exhibit distinct resistance profiles. Recent studies have shown that borinic acid HIV-1 protease inhibitors, which can act both associatively and competitively, have a higher affinity for HIV-1 protease variants than compounds that are strictly transition state analogs. Furthermore, such inhibitors were found to …

Designing And Constructing A Research Grade Scanning Tunneling Microscope System For Imaging Individual Molecules In Surface Self-Assembly, William P. Klein

Undergraduate Honors Theses

The invention of the scanning tunneling microscope (STM) 25 years ago gave researchers the ability to peer directly inside the fascinating world of molecular structures. Since that time, the design of STMs has be refined, allowing researchers to custom build their own STMs to meet their specific needs. A research grade STM was designed and constructed, along with a very stable two stage extension spring vibration isolation system. This STM was specifically designed to image molecular self-assembly at surfaces at a fraction of the cost of comparable research grade STMs currently available. The STM was constructed out of a machinable …

Synthesis Of Nitrogen-Containing Heterocycles From The Reaction Of Amidrazones With \Alpha-Haloesters, Hany M. Dalloul, Peter H. Boyle

Turkish Journal of Chemistry

The reaction of amidrazones 1 with \alpha-haloesters 2 formed 1,3,5-substituted 4,5-dihydro-1,2,4-triazin-6-ones (4a-z) rather than 1,2,4-triazin-5-one derivatives (5a-z). The microanalysis and spectral data of the synthesized compounds are in full agreement with their molecular structure.

Synthesis And Cytotoxic Activity Of Platinum(Ii) And Platinum(Iv) Complexes With 2-Hydroxymethylbenzimidazole Or 5(6)-Chloro-2-Hydroxymethylbenzimidazole Ligands Against Mcf-7 And Hela Cell Lines, Semra Utku, Fatma Gümüş, Si̇bel Gür, Aykut Özkul

Turkish Journal of Chemistry

Four platinum(II) and 4 platinum(IV) complexes with the structures [PtL_2Cl_2], [PtL_2I_2], [PtL_2Cl_4], and [PtL_2Cl_2(OH)_2] (L = 5(6)-non/orchloro-substituted-2-hydroxymethylbenzimidazole ligands as ``non-leaving groups''), respectively, were synthesized and characterized by their elemental analyses, and IR and ^1H-NMR spectra. In vitro cytotoxic activities of the platinum(II) and platinum(IV) complexes were tested against the human MCF-7 (breast cancer) and HeLa (cervix cancer) cell lines using the cell culture method. In general, the platinum(II) complexes were more active than the corresponding platinum(IV) complexes. The complexes, which were found to be less active than cisplatin, exhibited cyctotoxicity comparable to carboplatin on the human MCF-7 and HeLa cell …

Characterization And Co Oxidation Activity Studies Of Co-Based Catalysts, Fi̇li̇z Balikçi, Çi̇ğdem Güldür

Turkish Journal of Chemistry

Cobalt oxide based catalysts were developed for carbon monoxide oxidation at low temperature. The catalysts were prepared by co-precipitation and calcined at 200 °C. Several techniques were used to characterize the catalysts, such as X-ray diffractometer system, N_2 physisorption measurements, scanning electron microscope (SEM), and X-ray photoelectron spectroscopy. Carbon monoxide oxidation studies were carried out to investigate the relation between the characteristic properties of the catalysts and the catalytic activity. Catalytic activity measurements were studied from room temperature to 200 °C, using a feed composition of 1% CO, 21% O_2, and remaining He. X-ray studies showed that the catalysts have …

Abstraction Of Dimensional Relevance Of Molecular Representation: Generation Of Novel Inhibitors Against Malarial Plasmodium Falciparum Plasmepsin Iv, Christopher B. Abdul-Wahid

Undergraduate Honors Theses

The malarial parasite Plasmodium falciparum is endemic to 50% of the world's population, killing three million people a year, many of whom are children under five years of age. Due in part to the development of malarial resistance to current drug therapies, novel drug targets are being sought. The malarial hemolytic aspartic protease Plasmepsins are such targets of rational drug design.

We are developing a methodology to rapidly generate combinatorial libraries of chemical structures using a one-dimensional representation (Simplified molecular input line entry specification (SMILES)) of a molecule, to automatically generate a minimized three-dimensional representation (SYBYLMOL2), and to screen this …

Synthesis Of Novel Aziridine Derivatives Of Podocarpic Acid, Stephen Rhoden

Electronic Theses and Dissertations

Podocarpic acid (a diterpenoid resin acid extracted from the Podocarpacea specie of plants) has shown cytotoxicity against carcinoma of the nasopharynx. Since this discovery has been made, research has been performed in order to alter the structure of the resin acid so as to increase the anticancer activity. The carboxylic acid and phenol functional groups, which are present in podocarpic acid, make it possible to synthesize new derivatives selectively at the C-15, C-13, and C-7 positions as well as by substitution of the phenol hydroxyl group. Thus numerous derivatives can be prepared, in high yield, for the purpose of investigating …

A Novel Processing Route For The Production Of Nanoparticulate Zinc Oxide Using An Isophthalate Precursor, Grainne Duffy, Declan Mccormack, Suresh Pillai

Articles

Zinc oxide nanoparticles have been processed from a novel isophthalate precursor. In contrast to those processed from an oxalate precursor, this material exhibits three-dimensional, non-directional aggregation behaviour.

Such non-directional aggregation of uniaxial crystallites may allow for the production of structures with a higher proportion of catalytically active surfaces than can be prepared through conventional sol–gel methods. XRD,

FTIR, TEM and SEM were used to characterize the synthesized materials.

Zinc oxide particles synthesized by using isophthalic acid (C6H4-1,3-(COOH)2) are found to be slightly smaller than the previously reported materials prepared through chelation with oxalic acid (H2C2O2・2H2O).

Silver Doped Titanium Dioxide Nanomaterials For Enhanced Visible Light Photocatalysis, Michael Seery, Reena George, Suresh Pillai, Patrick Floris

Articles

This paper presents a systematic study on two different preparation methods for titanium dioxide with silver. The silver can be incorporated by irradiating the reaction mixture during preparation to reduce silver ion to silver metal or by direct calcination of the sol–gel material to decompose silver nitrate to silver. Of the two methods, we found the latter produces a more effective photocatalytic material (6–50% improvement in catalytic efficiency), which is attributed to the fact that the silver is homogeneously dispersed throughout the material. The efficiency of the materials were examined using a Q-Sun solar simulator (visible light) and in Dublin …

Membrane Fragmentation By A 20-29 Fragment Of Human Islet Amyloid Polypeptide And Rat Amyloid Polypeptide, Shyamprasad Samisetti

Master's Theses and Doctoral Dissertations

A key factor in the development of type II diabetes is the loss of insulin-producing pancreatic beta cells. The amyloidogenic human Islet Amyloid Polypeptide (hIAPP, also known as human amylin) is believed to play a crucial role in this biological process. Previous studies have shown that hIAPP forms small aggregates that kill β-cells by disrupting the cellular membrane. In this study we report membrane fragmentation by hIAPP20-29 and the rat version, rIAPP20-29, using solid-state NMR experiments on nanotube arrays of anodic aluminum oxide containing aligned phospholipid membranes.

31P NMR results suggest that membrane fragmentation by hIAPP is related to peptide …

The Effect Of The Reducing Agent Triphenylphosphine On Arachidonic Acid Metabolism By Prostaglandin H2 Synthase, Lalini Ailaboina

Master's Theses and Doctoral Dissertations

Prostaglandin H2 synthase (PGHS) catalyzes the conversion of arachidonic acid to prostaglandin endoperoxide (PGH2), which is a precursor to a variety of prostaglandins that function as hormones. Gas chromatography combined with mass spectrometry is employed to look for the novel products produced by reaction of triphenylphosphine with arachidonic acid prior to and during the PGHS reaction. Triphenylphosphine (TPP) is known to reduce hydro peroxides to alcohols and is used in the present study to ascertain the extent to which hydroperoxides in arachidonic acid preparations and in PGHS contribute to enzyme activity. Incubation of PGHS with arachidonic acid that was treated …

Kinetics Of The Ligand Exchange Reactions Between Bidentate Ligands And Rriethylenetetramine Nickelate (Ii) And Synthesis Of Boron (Iii) Subphthalocyanines With Various Boron Substitutions, Michael Christopher Cate

Master's Theses and Doctoral Dissertations

Part 1. The kinetics of the ligand exchange reaction between 5-methyl-1,10-phenanthroline and triethylenetetramine nickel (II) were studied spectrophotometrically over the pH range of 5.2 to 8.0 at 25oC. A ternary complex Ni(Trien)(5MP) forms within a few seconds and subsequently reacts with 5MP to form Ni(5MP)3. The reaction is first-order with respect to: [5MP], [Ni(Trien)(5MP)] and [H+]. The rate law is given by:

k dt d[Ni(trien)] = ( − MP Ni(trien)(5MP) + kH, 5MP Ni(trien)(5MP) [H+]) [Ni(trien)][5mp]

where: 5MP is 5-methyl-1,10-phenanthroline and k is the first order rate constant that has units of 1/time.

kH, 5mp Ni(trien)(5mp) = 9.78 X 104 …

Development Of A Microwave-Assisted Epoxide Aminolysis And Investigation Of The Aza-Cope Rearrangement--Mannich Cyclization For Alkaloid Synthesis, Brendan Roberto D'Souza

Master's Theses and Doctoral Dissertations

β-Amino alcohols are important organic compounds with numerous applications. Commonly β-amino alcohols are prepared by ring opening of epoxides using an amine nucleophile and a catalyst or promoter. Ring opening can take place by the SN1 pathway or the SN2 pathway, but no single catalyst or promoter consistently gives SN2 selectivity. Additionally, long reaction times are often required to obtain adequate yields. We have demonstrated that microwave heating reduces reaction times for the aminolysis of both reactive and unreactive, sterically hindered epoxides. These reactions were accomplished with various amines. In all cases, only one equivalent of amine and epoxide were …

Effect Of Counter Ion Concentration Added With Mixture Of Water And Ethylene Glycol On Krafft Temperature Of Sodium Dodecyl Sulfate, Sateesh Krishna Chand Chundru

Master's Theses and Doctoral Dissertations

Surfactants are amphiphilic organic compounds having both hydrophobic and hydrophilic groups. Surfactants in solution form aggregates known as micelles. The minimum temperature at which surfactants forms micelles is known as Krafft temperature. The Krafft temperature of sodium dodecyl sulfate (SDS) was measured at various counter ion concentrations in two solvent systems, water and 10% ethylene glycol. The Krafft temperature of sodium dodecyl sulfate increased in both water and 10% ethylene glycol with increasing counter ion concentration. The Krafft temperature of sodium dodecyl sulfate in 10% ethylene glycol was higher than the Krafft temperature of sodium dodecyl sulfate in water, at …

Synthesis Of An Isotopically Labelled Analog Of The Antimicrobial Peptide Ll-37, Rajesh Penumatcha

Master's Theses and Doctoral Dissertations

LL-37 is a cationic cathelin-associated broad spectrum antibiotic peptide of human neutrophils. Its mechanism of action is by disruption of the bacterial cell membrane structure. LL-21 is a simplified form of the peptide that contains only the core portion of LL-37, which retains antimicrobial activity and is easier to synthesize. We synthesized an 15N –Val-labeled LL-21 peptide which allows us to perform antimicrobial assays to know the antimicrobial activity of the new peptide LL-21 on various gram positive and gram negative bacteria. We found that our new peptide LL-21 shows good minimum inhibitory concentrations on various gram positive and gram …

Mesoporous Matrices For Quantum Computation With Improved Response Through Redundance, T. E. Hodgson, Massimo F. Bertino, Nicholas Leventis, Irena D'Amico

Physics Faculty Research & Creative Works

We present a solid state implementation of quantum computation, which improves previously proposed optically driven schemes. Our proposal is based on vertical arrays of quantum dots embedded in a mesoporous material which can be fabricated with present technology. The redundant encoding typical of the chosen hardware protects the computation against gate errors and the effects of measurement induced noise. The system parameters required for quantum computation applications are calculated for II-VI and III-V materials and found to be within the experimental range. The proposed hardware may help minimize errors due to polydispersity of dot sizes, which is at present one …

Crosslinking 3d Assemblies Of Silica Nanoparticles (Aerogels) By Surface-Initiated Free Radical Polymerization Of Styrene And Methylmethacrylate, Nicholas Leventis, Chariklia Sotiriou-Leventis, Sudhir Mulik

Chemistry Faculty Research & Creative Works

Quasi-stable, ultra-low density, three-dimensional assemblies of nanoparticles are referred to as aerogels. Aerogels are open-cell foams derived from supercritical fluid (SCF) drying of wet gels. Their large internal void space is responsible for low dielectric constants, low thermal conductivities and high acoustic impedance. At the same time though those materials are fragile and impractical for high load applications. The fragility problem has been addressed by casting a thin conformal polymer coating over the entire internal porous surface of the nanostructure.1 That process is referred to as crosslinking. The coating connects chemically skeletal nanoparticles and renders interparticle necks wider. Thus, the …

Irradiation And Metal-Containing Conjugated-Polymer Nanocomposites, Frank D. Blum, Zhe-Fei Li, Sunil K. Pillalamarri, Massimo F. Bertino

Chemistry Faculty Research & Creative Works

In recent years, there has been considerable interest in inorganic/organic hybrid materials that combine the desirable properties of both classes. These composite materials may find significant application in a variety of applications such as sensors, memory and energy conversion, to name just a few. In our laboratories, we have recently made a series of studies on the production of polymer nanofibers and their composites with nanometals. Much of this work has focused on the production of polyaniline (PANI) nanofibers that have been made from one-pot syntheses in aqueous solutions where the polymerization was influenced by -radiation1 or UV-radiation.2 in the …

Structural Manipulation Of Pyrrole-Terminated Dendrimers To Create A More Efficient Encapsulation/Release System, Henry Wiggins

LSU Doctoral Dissertations

This work demonstrates the ability to manipulate the structure of pyrrole-terminated dendrimers by modifying solution conditions which directly affects their encapsulation properties. Investigations were conducted using FTIR and 2D NMR to determine the location of end groups. NMR relaxation studies were conducted at various temperatures and different solution pH to gain an understanding of the relative mobility and rigidity of different areas of the dendrimer. It was found that that the release properties were affected by the solution pH and the presence of salt. Further the effectiveness of retaining molecular guests by oligo-pyrrole terminated dendrimers with a range of oligomer …

Investigation Of Phospholipid Tubule Morphology For Use In Drug Delivery, Colleen Colson Garrett

LSU Doctoral Dissertations

Spherical vesicles consisting of phosphatidylcholines in which diacetylene groups have been inserted in the hydrocarbon tail centers give rise to hollow cylindrical tubes, known as “tubules”. The study of tubules has become an area of intense interest in recent years due to their unusual morphology, which raises several profound theoretical issues and suggests their use in a variety of applications. Tubule hollowness suggests medical and industrial encapsulations as well as filtration and purification applications. These potential uses, e.g., for drug and gene delivery, requires optimization of their morphology for the application. Tubules have many technologically desirable properties, such as a …

Jonas Kamlet (1914-1960) Chemist/Entrepreneur, Dean F. Martin, Barbara B. Martin

Chemistry Faculty Publications

Jonas Kamlet, Ph.D., as a chemist, inventor, and a significant entrepreneur who founded Kamlet Laboratories in New York City that became the model of a successful consulting firm. Among his hundreds of patents and inventions were a tablet that could be used to measure glucose in urine, a treated strip that could detect pregnancy, a fodder for ruminants that used newsprint, and biuret (a self-condensation product of urea) that could be used as a non-protein component of fodder. Following his death in an airplane collision on December 16, 1960, his wife and collaborator (and later a resident of Florida) carried …

Concomitant Polymorphism In 1,2-Bis(9-Anthryl)Acetylene, Rebecca Goldstein

Honors Theses

This thesis details the serendipitous discovery of the phenomenon of concomitant conformational polymorphism found to exist in 1,2-bis(9-anthryl)acerylene. 1,2-bis(9anthryl)acetylene is a previously published molecule. However, the published crystal structure showed the molecule to be completely planar, and to crystallize in the form of orange needles. While this form of the crystal was indeed found during the synthesis of 1,2-bis(9anthryl)acetylene, a new polymorph, crystallizing as yellow prisms, was also discovered. This yellow polymorph was found by X-ray crystallography to be monoclinic with an angle of 66.7 between the anthracene planes. The planar polymorph 1,2-bis(9-anthryl)acetylene was also found by X-ray crystallography to …

Detailed Mechanistic And Optimization Of The Photochemical Production Method Of Superoxide, Ta-Chung Ong

Honors Theses

The highly reactive nature of superoxide anion presents an analytical challenge to prepare stable standards for instrument calibration. McDowell et al. (1983) developed a convenient method of superoxide production based on continuous photolysis of benzophenone and acetone in oxygen saturated, alkaline, 2-propanol solution. In the McDowell reaction, ketones are photolyzed to their triplet state, and then reacted with alcohol to produce ketyl radicals that react with oxygen to produce superoxide. This study investigated the mechanism and rate of these reactions by Laser Flash Photolysis (LFP). Reaction rate constants for the reaction between the benzophenone triplet and ethanol was 5.5 x …

Intramolecular Chemistry Of Ss-Acetoxyethylidene And Photochemical Generation Of Vinylidenes, Jennifer M. Nguyen

Honors Theses

The parent carbene ß-acetoxyethylidene has been previously generated by the photolysis of its precursor, acetic acid 1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl methyl ester. Mechanistic studies on ß-acetoxyethylidene have indicated the possibilities of three rearrangement pathways to the formation of vinyl acetate: a proton shift, an acyl shift, and a cyclic rearrangement (see Figure 8). A deuterium labeling study involving the replacement of the hydrogens on the methylene carbon has indicated that the simple 1,2-H shift was the primary manner of rearrangement, with an 82% yield of product. However, a primary kinetic isotope effect may have occurred due to the greater strength of a C-D …

Physicochemical Properties Of Individual And Mixed Oxides Of Sio2, Al203, Tio2‚ And Photocatalytic Behaviour Of Organosilane Modified St Samples, Kalyani Gude

Masters Theses

A variety of oxides such as silica, alumina, titania and mixed oxides such as silica/alumina (SA), silica/titania (ST) and alumina/silica/titania (AST) are investigated by TGA and FTIR. These mixed oxides are analyzed because of their applications as catalysts. Thermogravimetric analysis is done on all the samples to determine the temperature at which the weakly adsorbed water is lost and the surface is left with only surface hydroxyls. TGA data showed the loss of most of the adsorbed water at around 100°C.

From the diffuse reflectance FTIR spectra taken at 200 and 300°C the silanol content is estimated from the 3740 …

Zinc(Ii) Incorporation Into Porphyrin Cytochrome C As A Function Of Temperature, Urea Concentration And Zinc(Ii) Acetate Concentration And The Urea And Guanidine Hydrochloride Induced Unfolding Of Porphyrin Cytochrome C, Sireesha Potula

Masters Theses

The objective of this thesis is to address the question of whether the removal of the native iron(II) ion in cytochrome c (cyt c) and substitution by a different metal ion affects the overall structural stability. We have studied the incorporation of zinc(II) into metal-free porphyrin cytochrome с (H2cyt) and investigated the structural stability of cyt c in the absence of the iron(II) ion and in the presence of the zinc(II) ion by different spectroscopic techniques. Compared to H2cyt, zinc-substituted cytochrome c (Zncyt) has a significantly different absorbance spectrum, so we monitor over time the change in absorbance upon addition …

Metal-Substituted Cytochrome C: Manganese (Ii) Incorporation Kinetics And Structural Stability Studies Of Native Iron Cytochrome C, Porphyrin Cytochrome C, Zinc Cytochrome C And Manganese Cytochrome C, Vineela Gundala

Masters Theses

Metalloproteins have the capacity to bind various metal ions. In spite of this seemingly diverse choice of cofactors, metalloproteins generally bind only their cognate metal in vivo. Cytochrome c (cyt c) binds Fe porphyrin in vivo. The main objective of this thesis is to investigate why nature selects Fe porphyrin as the prosthetic group in heme proteins and how removal of the native Fe in cyt c and substitution by different metal ions affects the local coordination environment, overall structural stability, and biological function. Our goal is to prepare and characterize metal-free cytochrome c, socalled porphyrin cytochrome c (H2cyt), and …