Chemistry Commons^™

Chemical Constituents Of Cryptocarya Densiflora., Nurul Nazneem Wan Othman

Student Works (2010-2019)

The extraction of alkaloids from the Malaysian Cryptocarya densiflora has been carried out in this study. The alkaloids were extracted from the bark and leaves of this species using acid base extraction and the crude alkaloids obtained were subjected to extensive chromatographic techniques such as thin layer and column chromatography. The structural elucidation of the purified alkaloids were performed with the aid of spectroscopic methods i.e. 1H NMR, 13C NMR, 2D NMR, IR, UV and LCMS. Investigation of the alkaloidal content from the bark of Cryptocarya densiflora afforded six alkaloids and their structures were elucidated as laurotetanine 63, isocaryachine 64, …

New Palm Oil Products By Enzymatic Interesterification And Dry Fractionation., Saw Mei Huey

Student Works (2010-2019)

Palm olein is one of the major palm oil products that domestically and industrially used as cooking or frying oil. Palm olein tends to crystallize at low temperature that limits its usage in temperate countries. In spite of various nutritional studies, palm olein is also not well considered as recommended choice due to its higher saturation content. Against these factors, there is a need to reduce its saturation content. In this study, the saturation content in palm olein was reduced through the combination of enzymatic interesterification and dry fractionation. Enzymatic interesterification allows interchanging of acyl groups between and within triacylglycerols …

Biochemical Characterization Of Human Mismatch Recognition Proteins Mutsα And Mutsβ, Lei Tian

University of Kentucky Doctoral Dissertations

The integrity of an organism's genome depends on the fidelity of DNA replication and the efficiency of DNA repair. The DNA mismatch repair (MMR) system, which is highly conserved from prokaryotes to eukaryotes, plays an important role in maintaining genome stability by correcting base-base mismatches and insertion/deletion (ID) mispairs generated during DNA replication and other DNA transactions. Mismatch recognition is a critical step in MMR. Two mismatch recognition proteins, MutSα (MSH2-MSH6 heterodimer) and MutSβ (MSH2-MSH3 heterodimer), have been identified in eukaryotic cells. MutSα and MutSβ have partially overlapping functions, with MutSα recognizing primarily base-base mismatches and 1-2 nt ID mispairs …

Explorations In Homeoviscous Adaptation And Mass Spectral Analysis Of Membrane Lipids, Michael Douglas Timmons

University of Kentucky Doctoral Dissertations

The focus of this dissertation is centered on the mass spectral analysis of lipids and changes occurring in keeping with the concept of homeoviscous adaptation [1]. Homeoviscous adaptation is the process of modification of membrane lipids in response to environmental stimuli [1]. Dissertation investigations applied this concept to prokaryotic and eukaryotic organisms, and expanded the perception of environmental factors from exogenous organic solvents to intracellular environment.

The field of lipidomics deals with the analysis of phospholipid and fatty acid components of membranes the changes that occur due to environmental stimuli and their biological significance [2-6]. The high sensitivity of mass …

In Vivo Oxidative Stress In Alzheimer Disease Brain And A Mouse Model Thereof: Effects Of Lipid Asymmetry And The Single Methionine Residue Of Amyloid-Β Peptide, Miranda Lu Bader Lange

University of Kentucky Doctoral Dissertations

Studies presented in this dissertation were conducted to gain more insight into the role of phospholipid asymmetry and amyloid-β (Aβ)-induced oxidative stress in brain of subjects with amnestic mild cognitive impairment (aMCI) and Alzheimer disease (AD). AD is a largely sporadic, age-associated neurodegenerative disorder clinically characterized by the vast, progressive loss of memory and cognition commonly in populations over the age of ~65 years, with the exception of those with familial AD, which develop AD symptoms as early as ~30 years-old. Neuropathologically, both AD and FAD can be characterized by synapse and neuronal cell loss in conjunction with accumulation of …

Identification And Quantification Of Pesticides Residue In Vegetables By Liquid Chromatography Quadrupole-Time-Of Flight Mass Spectrometry (Lc-Q-Tof Ms)., Tin Ae Ru

Student Works (2010-2019)

A liquid chromatography tandem mass spectrometry (LC-Q-TOF MS) technique was used to simultaneously determine six types of carbamates and organophosphorus pesticides residue in vegetables. The pesticides were extracted by ultrasonic solvent extraction method using ethyl acetate as the extraction solvent followed by Florisil column clean up. Four types of common consumed vegetables from local hypermarket were used to study the recovery. The accurate mass measurement and retention time were used to identify and determine the empirical formula of the pesticides. The mass accuracy errors were less than 7 ppm for all the investigated pesticides. The limit of detection (LOD) were …

Adsorption Of Lead (Ii) By A Non-Living Algal Biomass., Mudher A. Hussein

Student Works (2010-2019)

Conventional techniques for removing dissolved heavy metals are only practical and cost-effective when applied to high strength wastes with heavy metal ion concentrations greater than 100 ppm. The possibility of using a non-living algal biomass to solve this problem was studied. Lead(II) was used in this study because it has been reported to cause several disorders in human. The non-living algal biomass was obtained from the filamentous green alga Spirogyra neglecta. The effects of initial concentration and contact time, pH, and temperature on the adsorption of lead(II) by the non-living algal biomass were studied. The equilibrium isotherms and kinetics were …

Progress Toward The Total Synthesis Of Lyconadin A, Yu Zhang

Theses and Dissertations

Lyconadin A is a pentacyclic Lycopodium alkaloid isolated from the club moss Lycopodium complanatum with antitumor properties. We have developed a novel 7-exo/6-exo acyl radical cascade cyclization as a method of making the bicyclo[5.4.0]undecane ring system of lyconadin A. The model products are trans-fused ring systems, while a cis-fused ring system is needed in lyconadin A. We have discovered a method to convert the trans-fused model cascade cyclization product into the desired cis isomer. Based on Donohoe's pyridone synthesis, we developed a method for the construction of 5-alkyl and 3,5-dialkyl-6-carbomethoxy-2-pyridones, the former of which …

The Ecology Of The Peaks Of Otter Salamander (Plethodon Hubrichti) In Sympatry With The Eastern Red-Backed Salamander (Plethodon Cinereus), Norman Reichenbach, Andrew Kniowski

Faculty Publications and Presentations

The Peaks of Otter Salamander, Plethodon hubrichti, is found along a 19 km length of the Blue Ridge Mountains, Virginia, USA, often in sympatry with the Eastern Red-backed Salamander, P. cinereus. In a sympatric area of Bedford County, Virginia, we conducted a mark-recapture study on a 10 × 10 m site. Surface densities of salamanders increased as the number of days without precipitation prior to a collection event increased. This suggests vertical movements in response to surface moisture. When salamanders returned to the surface after rain, individuals appeared to “shuffle” between rocks and likely, leaf litter. That is, we were …

Subcutaneous Administration Of Tc007 Reduces Disease Severity In An Animal Model Of Sma, Virginia B. Mattis, Marina Y. Fosso, Cheng-Wei Tom Chang, Christian L. Lorson

Chemistry and Biochemistry Faculty Publications

Background Spinal Muscular Atrophy (SMA) is the leading genetic cause of infantile death. It is caused by the loss of functional Survival Motor Neuron 1 (SMN1). There is a nearly identical copy gene, SMN2, but it is unable to rescue from disease due to an alternative splicing event that excises a necessary exon (exon 7) from the majority of SMN2-derived transcripts. While SMNΔ7 protein has severely reduced functionality, the exon 7 sequences may not be specifically required for all activities. Therefore, aminoglycoside antibiotics previously shown to suppress stop codon recognition and promote translation read-through have been examined to increase the …

Synthesis And Evaluation Of N6,5'-Bis-Ureido-5'-Amino-5'-Deoxyadenosine Derivatives: Novel Nucleosides With Antiproliferative And Protein Kinase Binding Activities, Marcelio Oliveira

Theses and Dissertations

A new series of N6,5'-bis-ureido-5'-amino-5'-deoxyadenosine derivatives was prepared and evaluated for anticancer activities using the NCI 60 panel of human cancers. Certain of the derivatives showed promising activities (low micromolar GI50's) against several of the representative cancers. These included cell lines from the following general cell types in the NCI 60: Leukemia, Breast, Central Nervous System, Non-Small Cell Lung, Ovarian, Prostate, Renal, and Colon cancers. Select compounds were also screened for their affinities for protein kinases. The synthesis of the compounds was straightforward and involved N6 acylation with arylisocyanates, preceded by activation and nucleophilic substitution of the 5'-position to give …

Correlating Molecular Phylogeny With Venom Apparatus Occurrence In Panamic Auger Snails (Terebridae), Mandë Holford, Nicolas Puillandre, Maria Vittoria Modica, Maren Watkins, Rachel Collin, Eldredge Bermingham, Baldomero M. Olivera

Publications and Research

Central to the discovery of neuroactive compounds produced by predatory marine snails of the superfamily Conoidea (cone snails, terebrids, and turrids) is identifying those species with a venom apparatus. Previous analyses of western Pacific terebrid specimens has shown that some Terebridae groups have secondarily lost their venom apparatus. In order to efficiently characterize terebrid toxins, it is essential to devise a key for identifying which species have a venom apparatus. The findings presented here integrate molecular phylogeny and the evolution of character traits to infer the presence or absence of the venom apparatus in the Terebridae. Using a combined dataset …

Lipid-Protein Interactions Probed By Electron Crystallography, Steve L. Reichow, Tamir Gonen

Chemistry Faculty Publications and Presentations

Electron crystallography is arguably the only electron cryomicroscopy (cryoEM) technique able to deliver an atomic-resolution structure of membrane proteins embedded in the lipid-bilayer. In the electron crystallographic structures of the light driven ion pump, bacteriorhodopsin, and the water channel, aquaporin-0, sufficiently high resolution was obtained and both lipid and protein were visualized, modeled and described in detail. An extensive network of lipid-protein interactions mimicking native membranes is established and maintained in two-dimensional (2D) crystalline vesicles used for structural analysis by electron crystallography. Lipids are tightly integrated into the protein's architecture where they can affect the function, structure, quaternary assembly and …

Unlv Magazine, Matthew K. Jacobsen, Holly Ivy De Vore, Lisa Arth, Cate Weeks, Greg Lacour, Tony Allen, Afsha Bawany, Barbara Cloud, Gian Galassi, Phil Hagen, Karyn S. Hollingsworth, Michelle Mouton, Erin O'Donnell

UNLV Magazine

No abstract provided.

Pore Size Characterization Of Monolithic Capillary Columns Using Capillary Flow Porometry, Yan Fang

Theses and Dissertations

A simple capillary flow porometer (CFP) was assembled for pore structure characterization of monolithic capillary liquid chromatography columns based on ASTM standard F316-86. Determination of differential pressures and flow rates through dry and wet samples provided the necessary information to determine the through-pore throat diameter, bubble point pore diameter, mean flow pore diameter, and pore distribution. Unlike measurements in bulk using traditional techniques to provide indirect information about the pore properties of monolithic columns, monoliths can be characterized in their original chromatographic forms with this system. The performance of the new CFP was first evaluated by characterizing the pore size …

Gas Phase Chiral Recognition, Characterization Of Porous Polymer Monolith Nanospray Ionization, And The Negative Mode Crafti Method Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Nannan Fang

Theses and Dissertations

Our group has been studying chiral recognition in gas phase using mass spectrometry for more than 10 years. We are interested in gas phase studies of fundamental interactions because the gas phase avoids complications and masking effects that may arise upon solvation. Therefore, the results of gas phase experiments can be directly compared with those of high-level computational studies. In chapter 2, I studied the roles of hydrogen bonding and pi stacking in gas phase chiral recognition between aromatic crown molecules and aromatic amines. High affinity between host and guest doesn't necessarily result in better recognition. If the affinity is …

Apoptotic And Chemotherapeutic Properties Of Iron (Iii)-Salophene In An Ovarian Cancer Animal Model, Thilo S. Lange, Carolyn Mccourt, Rakesh K. Singh, Kyu Kwang Kim, Ajay P. Singh, Brian S. Luisi, Onur Alptürk, Robert M. Strongin, Laurent Brard

Chemistry Faculty Publications and Presentations

The cytotoxicity of organometallic compounds iron(III)-, cobalt(III)-, manganese(II)-, and copper(II)-salophene (-SP) on platinum-resistant ovarian cancer cell lines was compared. Fe-SP displayed selective cytotoxicity (IC(50) at ~1 muM) against SKOV-3 and OVCAR-3 cell lines while Co-SP caused cytotoxic effects only at higher concentrations (IC(50) at 60 muM) and Cu-SP effects were negligible. High cytotoxicity of Mn-SP (30-60 muM) appeared to be nonspecific because the Mn-chloride salt reduced cell viability similarly. The effect of Fe-SP at 1 muM proved to be ovarian cancer cell selective when compared to a panel of cell lines derived from different tumors. The first irreversible step in …

Theoretical Studies Of 2,3 -Sigmatropic Rearrangements Of Allylic Selenoxides And Selenimides, Craig A. Bayse, Sonia Antony

Chemistry & Biochemistry Faculty Publications

Density-functional theory is used to model the endo and exo transition states for [2,3]-sigmatropic rearrangement of allylic aryl-selenoxides and -selenimides. The endo transition state is generally preferred for selenoxides if there is no substitution at the 2 position of the allyl group. Based upon the relative energies of the endo and exo transition states, enantioselectivity of rearrangements is expected to be greatest for molecules with substitutions at the 1- or (E)-3- position of the allyl group. Ortho substitution of a nitro group on the ancillary selenoxide phenyl ring reduces the activation barriers, increases the difference between the endo and exo …

Total Synthesis Of (-)-Acutumine, Fang Li

Theses and Dissertations

Acutumine is a tetracyclic alkaloid isolated from the Asian vine Menispermum dauricum with selective T-cell cytotoxicity and antiamnestic properties. We have developed a total synthetic route to this congested alkaloid, during which we also found a novel, stereoselective radical-crossover reaction that combines an intramolecular radical conjugate addition with a subsequent enolate hydroxylation. Key features of this synthesis also include a reagent-controlled diastereoselective ketone allylation, an anionic oxy-Cope rearrangement to form a congested quaternary sterocenter, a pyridine-mediated selective ozonolysis, and a Lewis acid promoted Michael-type cyclization.

Development Of Biocompatible Polymer Monoliths For The Analysis Of Proteins And Peptides, Yun Li

Theses and Dissertations

Biocompatibility is an important issue for the development of chromatographic stationary phases for the analysis of biomolecules (including proteins and peptides). A biocompatible stationary phase material is a material that resists nonspecific adsorption of biomolecules and does not interact with them in a way that would alter or destroy their structures or biochemical functions. The monolithic column format is a good alternative to typical spherical particle packed columns for capillary liquid chromatography of biomacromolecules. Several novel anion-exchange polymer monoliths for the analysis of proteins were synthesized for improved biocompatibility. Two novel polymeric monoliths were prepared in a single step by …

Real-Time Virus Analysis Via Image Charge Detection Surface Induced Dissociation Tandem Mass Spectrometry, Seth T. Call

Theses and Dissertations

This thesis reports on the development of a novel mass spectrometer combining image charge detection with surface induced dissociation for real-time analysis of intact viruses. Protonated viruses produced using electrospray are accelerated and subsequently impact on a solid surface. Capsid peptides released during the impact are analyzed using time-of-flight mass spectrometry. Image charge detection is used to measure the mass and charge states of structurally intact, electrosprayed viruses prior to impact. Since virus capsids are composed of loosely-bound proteins, collision of viruses with surfaces at moderate impact energies could release intact proteins. The masses and numbers of different protein types …

Design And Characterization Of A Human Exposure Chamber And Inversion Episodes In Salt Lake City, Utah In January/February Of 2009, Roman Yuri Kuprov

Theses and Dissertations

Research on health effects of particulate matter (PM) has been a very active area in the last two decades. One plausible mechanism by which exposure to PM affects human health includes modification of autonomic endothelium function. Decreased endothelium activity causes heightened risks of cardiovascular disease. A human exposure chamber designed to conduct experiments to quantify diminished function of endothelium from short term exposure to PM is described. The chamber consists of two stages for containment and pre-treatment of PM and exposure of human subjects. Concentrations of CO, CO2, NO, NO2, O3, and PM2.5, are monitored and controlled in the exposure …

Undergraduate Research Opportunities Program, University Of Nevada Las Vegas, College Of Sciences

Undergraduate Research Opportunities Program (UROP)

No abstract provided.

The Study Of Variations In The Properties Of Biodiesel On Addition Of Antioxidants, Hiranmayee Kandala

Masters Theses & Specialist Projects

This research studies variations in biodiesel upon addition of different concentrations of antioxidant and petrodiesel additives. Oxidation onset temperature, oxidation induction time, oxidative stability, thermal stability, crystallization onset temperature and moisture retention properties of the biodiesel, with and without antioxidants have been studied. Antioxidants like BHT, BHA, PrG, Vit E and Vit C were added to the biodiesel during the study. These samples were analyzed using the PDSC, TGA, DSC and TGA-SA instrumentation.

The results of this research show an improvement in the OOT, OIT and Oxidative stability of biodiesel with the addition of antioxidants and by blending the biodiesel …

Synthesis And Characterization Of Bis-Phosphine Complexes With Transition Metals, Alicia L. Mcdaniel

Masters Theses & Specialist Projects

Extractants and extraction methodologies play a vital role in many industrial processes, from the concentration of precious metals from ores to the separation of longlived nuclei from radioactive waste as well as the removal of heavy metals from soils and water for remediation. The vast majority of extractants rely on the use of nitrogen, oxygen, sulfur or selenium as Lewis base donor atoms to form coordination complexes with the metal ions of interest. These extractants often make use of the chelate effect and/or the macrocyclic effect in order to form stable complexes. Some of the best known types of chelate …

Physico-Chemical Characteristics Of Storage-Ripened Mango (Mangifera Indica L.) Fruits Varieties Of Eastern Tanzania, O C Othman, G P Mbogo

Tanzania Journal of Science

Two mango (Mangifera indica L.) fruit varieties, Dodo and Viringe, from two localities of Eastern Tanzania, (Muheza in Tanga and Ifakara in Morogoro), were harvested as mature green fruits during early, mid and late season and allowed to ripen while stored at room temperature. The fruits were analyzed for their proximate composition (ash, titratable acidity, crude fat, crude fibre, moisture), reducing and total sugars content, ascorbic acid and total soluble solids content, concentration of four macro elements (Ca, Mg, K, Na) and seven heavy metals (Al, Cd, Cu, Fe, Mn, Pb, Zn). The results showed that the mango fruits had …

Plants As A Source Of Green Corrosion Inhibitors: The Case Of Gum Exudates From Acacia Species (A. Drepanolobium And A. Senegal), J Buchweishaija

Tanzania Journal of Science

The inhibitive performance of gum exudates from Acacia drepanolobium and Acacia senegal from Tanzania, towards the corrosion of mild steel in fresh water has been investigated. The experimental methods include potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies. The results indicate that gum exudates (Acacia drepanolobium and Acacia senegal) exhibit good inhibition characteristics to corrosion on mild steel under fresh water medium and the inhibition efficiency of up to 90.7% and 99.7% respectively was attained at 30 oC. Furthermore, the studies have shown that the inhibition performance remained above 90% on both Acacia exudates independent of the raise in temperature. …

Physical And Chemical Composition Of Storage-Ripened Papaya (Carica Papaya L.) Fruits Of Eastern Tanzania, O C Othman

Tanzania Journal of Science

The proximate composition (ash, titratable acidity, crude fat, crude fibre, moisture and sugars), soluble solids, ascorbic acid, polyphenol oxidase activity, macro-nutrients and heavy metal contents of storage-ripened papaya (Carica papaya L.) fruits from Mbezi, Dar es Salaam, Tanzania were determined. The determinations were repeated for early, middle and late-season papaya fruits. The fruits were always harvested at the mature green stage and allowed to ripen during room temperature storage. The results showed that papaya fruits had high moisture content (>85.5%), low acidity (<0.18% c.a.), low crude fat (0.10 g/100 g-edible portion), moderate crude fibre (1.45 g/100 g-edible portion), high ascorbic acid content (>84.5 mg/100 g- fw), moderate total sugars (>13.0%) and soluble solids (>12.9%) content. Early-season …

A Top-Down Proteomic Approach For The Discovery Of Novel Serum Biomarkers Of Pregnancy-Related Disease, Karen Merrell

Theses and Dissertations

The serum fraction of blood is an ideal material in which to search for novel biomarkers for disease. It is easily obtained through relatively non-invasive means, routinely collected, and a rich treasure-trove of information about the health of an individual. Cells react to signal molecules, take up nutrients, and release waste products, fragments that are the result of proteolysis, and other molecules out into the bloodstream. If these components are unique to the cells in question, that part of the complex mixture that is the blood stream can potentially characterize the health of the tissue or organ those cells are …

Ion Transport Behaviors Upstream And Downstream From The Sampling Cone Of An Inductively Coupled Plasma Mass Spectrometer, Haibin Ma

Theses and Dissertations

Inductively coupled plasma - mass spectrometry (ICP-MS) is the technique of choice worldwide for trace elemental determinations because of its excellent ionization ability, low detection limits and fast analysis speeds. However, the ICP-MS still suffers from some disadvantages, such as spectral overlap and severe matrix effects. Matrix effects or interferences, partly arise from changes in the analyte transmission through the interfacial region between the ICP and mass spectrometer with changes in sample matrix. Better understanding of the transmission behaviors of analyte through the sampling and skimmer cones will provide the insights needed to alleviate matrix interferences and to improve the …