Analytical Chemistry Commons^™

Design Of In Vivo Assays For Study Of Transport, Biocompatibility And Toxicity Of Nanoparticles, Kerry Jean Lee

Theses and Dissertations in Biomedical Sciences

This dissertation focuses on the design of new in vivo assays for study of transport, biocompatibility and toxicity of nanoparticles (NPs) in zebrafish embryos. We synthesized and purified spherical silver (Ag) NPs with diameters, ranging from 12 to 95 nm, that are stable (non-aggregated) in egg-water media. We developed new imaging approaches to characterize the sizes of single Ag NPs in zebrafish embryos at nanometer resolution by measuring their size-dependent plasmonic spectra and scattering intensity using dark-field optical microscopy and spectroscopy (DFOMS). We used single Ag NPs because they exhibit the high quantum yield (QY) of Rayleigh scattering and resist …

Strawberry Growth, Yield, Fruit Nutrition, And Control Of Verticillium Wilt With Pre-Plant Soil Fumigants, Ozone, And Biological Control, Justin J. Scurich

Master's Theses

Verticillium wilt is a widespread soilborne disease of strawberry historically controlled by soil fumigation with methyl bromide (MB). MB was banned by the United Nations in 1995 and will be completely phased out by 2015. Research has concentrated on alternative methods of disease control without finding a single alternative able to replace MB in widespread disease control and yield increase. For the current study, strawberries were greenhouse grown in container pots filled with soil from both infested and non-infested areas of a commercial strawberry field in Watsonville, CA. Treatments included pre-plant soil fumigation with commercially available formulations of methyl bromide, …

K-Shell X-Ray Spectroscopy Of Atomic Nitrogen, M. M. Sant'anna, Gunnar Ohrwall, Wayne C. Stolte, Alfred S. Schlachter, Dennis W. Lindle, B. M. Mclaughlin

Chemistry and Biochemistry Faculty Research

Absolute K-shell photoionization cross sections for atomic nitrogen have been obtained from both experiment and state-of-the-art theoretical techniques. Because of the difficulty of creating a target of neutral atomic nitrogen, no high-resolution K-edge spectroscopy measurements have been reported for this important atom. Interplay between theory and experiment enabled identification and characterization of the strong 1s → np resonance features throughout the threshold region. An experimental value of 409.64 ± 0.02 eV was determined for the K-shell binding energy.

Electrochemical Behavior Of Imidacloprid, Jie-Qiong Wang, Wang Zhang, Ming Chen, Guo-Wang Diao

Journal of Electrochemistry

The electrochemical behavior of imidacloprid（IDP）on glassy carbon electrode has been investigated by cyclic voltammetry. The result shows that the electrochemical reduction of IDP is irreversible and controlled by diffusion. At 25 ℃, the numbers of the electrons transferred of IDP in the electrochemical reaction are four. The diffusion coefficient of IDP is 2.44×10⁶ cm²·s^-1 and the diffusion activation energy is calculated to be 9.33 kJ·mol^-1.

Preparation And Rapid Analysis Of Antibacterial Silver, Copper And Zinc Doped Sol–Gel Surfaces, Brendan Duffy, Swarna Jaiswal, Patrick Mchale

Articles

The colonisation of clinical and industrial surfaces with microorganisms, including antibiotic-resistant strains, has promoted increased research into the development of effective antibacterial and antifouling coatings. This study describes the preparation of metal nitrate (Ag, Cu, Zn) doped methyltriethoxysilane (MTEOS) coatings and the rapid assessment of their antibacterial activity using polyproylene microtitre plates. Microtitre plate wells were coated with different volumes of liquid sol–gel and cured under various conditions. Curing parameters were analysed by thermogravimetric analysis (TGA) and visual examination. The optimum curing conditions were determined to be 50–70C using a volume of 200ul. The coated wells were challenged with Gram-positive …

Unusual Activities Of The Thioesterase Domain For The Biosynthesis Of The Polycyclic Tetramate Macrolactam Hsaf In Lysobacter Enzymogenes C3, Lili Lou, Haotong Chen, Ronald Cerny, Yaoyao Li, Yuemao Shen, Liangcheng Du

Ronald Cerny Publications

HSAF is an antifungal natural product with a new mode of action. A rare bacterial iterative PKSNRPS assembles the HSAF skeleton. The biochemical characterization of the NRPS revealed that the thioesterase (TE) domain possesses the activities of both a protease and a peptide ligase. Active site mutagenesis, circular dichroism spectra and homology modeling of the TE structure suggested that the TE may possess uncommon features that may lead to the unusual activities. The iterative PKS-NRPS is found in all polycyclic tetramate macrolactam gene clusters, and the unusual activities of the TE may be common to this type of hybrid PKS-NRPS.

Self-Assembling Subnanometer Pores With Unusual Mass-Transport Properties, Xibin Zhou, Guande Liu, Kazuhiro Yamato, Yi Shen, Ruixian Cheng, Xiaoxi Wei, Wanli Bai, Yi Gao, Hui Li, Yi Liu, Futao Liu, Daniel M. Czajkowsky, Jingfang Wang, Michael J. Dabney, Zhonghou Cai, Jun Hu, Frank V. Bright, Lan He, Xiao Cheng Zeng, Zhifeng Shao, Bing Gong

Xiao Cheng Zeng Publications

A long-standing aim in molecular self-assembly is the development of synthetic nanopores capable of mimicking the mass-transport characteristics of biological channels and pores. Here we report a strategy for enforcing the nanotubular assembly of rigid macrocycles in both the solid state and solution based on the interplay of multiple hydrogen-bonding and aromatic π − π stacking interactions. The resultant nanotubes have modifiable surfaces and inner pores of a uniform diameter defined by the constituent macrocycles. The self-assembling hydrophobic nanopores can mediate not only highly selective transmembrane ion transport, unprecedented for a synthetic nanopore, but also highly efficient transmembrane water permeability. …

Plasma Spectroscopic Techniques Applied To Biological And Environmental Matrices, Morgan Steele Schmidt

Electronic Theses and Dissertations

The purpose of this research was to apply the use of direct ablation plasma spectroscopic techniques, including spark-induced breakdown spectroscopy (SIBS) and laser-induced breakdown spectroscopy (LIBS), to a variety of environmental matrices. These were applied to two different analytical problems. SIBS instrumentation was adapted in order to develop a fieldable monitor for the measurement of carbon in soil. SIBS spectra in the 200 nm to 400 nm region of several soils were collected, and the neutral carbon line (247.85 nm) was compared to total carbon concentration determined by standard dry combustion analysis. Additionally, Fe and Si were evaluated in a …

Dynamic Light Scattering And Microelectrophoresis: Main Prospects And Limitations, Vuk Uskoković

Pharmacy Faculty Articles and Research

Microelectrophoresis based on the dynamic light scattering (DLS) effect has been a major tool for assessing and controlling the conditions for stability of colloidal systems. However, both the DLS methods for characterization of the hydrodynamic size of dispersed submicron particles and the theory behind the electrokinetic phenomena are associated with fundamental and practical approximations that limit their sensitivity and information output. Some of these fundamental limitations, including the spherical approximation of DLS measurements and an inability of microelectrophoretic analyses of colloidal systems to detect discrete charges and differ between differently charged particle surfaces due to rotational diffusion and particle orientation …

Ccpa Regulates Arginine Biosynthesis In Staphylococcus Aureus Through Repression Of Proline Catabolism, Austin S. Nuxoll, Steven M. Halouska, Marat R. Sadykov, Mark L. Hanke, Kenneth W. Bayles, Tammy Kielian, Robert Powers, Paul D. Fey

Department of Chemistry: Faculty Publications

Staphylococcus aureus is a leading cause of community-associated and nosocomial infections. Imperative to the success of S. aureus is the ability to adapt and utilize nutrients that are readily available. Genomic sequencing suggests that S. aureus has the genes required for synthesis of all twenty amino acids. However, in vitro experimentation demonstrates that staphylococci have multiple amino acid auxotrophies, including arginine. Although S. aureus possesses the highly conserved anabolic pathway that synthesizes arginine via glutamate, we demonstrate here that inactivation of ccpA facilitates the synthesis of arginine via the urea cycle utilizing proline as a substrate. Mutations within putA, rocD, …

Unraveling The Structural Complexity In A Single-Stranded Rna Tail: Implications For Efficient Ligand Binding In The Prequeuosine Riboswitch, Catherine D. Eichhorn, Jun Feng, Krishna C. Suddala, Nils G. Walter, Charles L. Brooks Iii, Hashim M. Al-Hashimi

Department of Chemistry: Faculty Publications

Single-stranded RNAs (ssRNAs) are ubiquitous RNA elements that serve diverse functional roles. Much of our understanding of ssRNA conformational behavior is limited to structures in which ssRNA directly engages in tertiary interactions or is recognized by proteins. Little is known about the structural and dynamic behavior of free ssRNAs at atomic resolution. Here, we report the collaborative application of nuclear magnetic resonance (NMR) and replica exchange molecular dynamics (REMD) simulations to characterize the 12 nt ssRNA tail derived from the prequeuosine riboswitch. NMR carbon spin relaxation data and residual dipolar coupling measurements reveal a flexible yet stacked core adopting an …

Crystalline Nano Structures, Barry Chin Li Cheung, Joseph Reese Brewer, Nirmalendu Deo

Department of Chemistry: Faculty Publications

The present invention comprises nano obelisks and nanostructures and methods and processes for same. The nano obelisks of the present invention are advantageous structures for use as electron source emitters. For example, the ultra sharp obelisks can be used as an emitter source to generate highly coherent and high energy electrons with high current.

Ƴ-Selective Directed Catalytic Asymmetric Hydroboration Of 1,1-Disubstituted Alkenes, Sean M Smith, Gia L. Hoang, Rhitankar Pal, Mohammad O. Bani Khaled, Liberty S. W. Pelter, Xiao Cheng Zeng, James M. Takacs

Xiao Cheng Zeng Publications

Directed catalytic asymmetric hydroborations of 1,1-disubstituted alkenes afford ƴ

-dioxaborato amides and esters in high enantiomeric purity (90–95% ee).

Single Molecule Studies Of Rna-Target Interactions, Sharla Leann Wood

Wayne State University Dissertations

We have used FRET, single molecule spectroscopy, and several other biophysical techniques to study how the folding of RNA allows it to perform its various functions by recognizing and binding a target ligand. We have shown that the c-di-GMP riboswitch undergoes a large, global conformational change upon binding of the ligand. The folding dynamics of the c-di-GMP riboswitch upon Mg2+ binding help to pre-organize the aptamer for efficient ligand binding and ultimately efficient gene expression. We have also investigated two instances, a fluorophore-binding aptamer and molecular beacon, where the folding of RNA can be used to detect an analyte. We …

Effect Of Low Endogenous Brain-Derived Neurotrophic Factor Levels On Striatal Dopamine Dynamics, Francis Kabui Maina

Wayne State University Dissertations

Many neurological diseases and disorders are a result of alterations with neurotransmitters, neuromodulators, and/or proteins. Specifically, one protein that has been linked to numerous neurological diseases and disorders such as Parkinson's disease, Huntington's disease, addiction, attention deficit hyperactivity disorder (ADHD), and depression is brain-derived neurotrophic factor (BDNF). As a trophic factor, BDNF role is to assist in the growth, survival, and differentiation of neurons. However, there is increasing evidence that BDNF may mediate neurotransmitter dynamics. Our goals were to understand how endogenous BDNF levels and aging modulate the dopamine (DA) dynamics in the mouse striatum. Two complementary neurochemical techniques, slice …

Determination Of Descriptors By Liquid-Liquid Partition And Chromatographic Methods, Thushara Namal Karunasekara

Wayne State University Dissertations

ABSTRACT

DETERMINATION OF DESCRIPTORS BY LIQUID-LIQUID PARTITION AND CHROMATOGRAPHIC METHODS

by

THUSHARA KARUNASEKARA

September 2012

Advisor: Prof. Colin F. Poole

Major: Chemistry (Analytical)

Degree: Doctor of Philosophy

Partition coefficients for varied compounds were determined for several totally organic biphasic systems using formamide, propylene carbonate, ethylene glycol or dimethyl sulfoxide as the base solvent and n-heptane, 1,2-dichloroethane, 1-octanol or isopentyl ether as the counter solvent. These partition coefficient databases are analyzed using the solvation parameter model facilitating a quantitative comparison of these systems with other totally organic and water-based partition systems. These totally organic biphasic solvent systems offer a complementary approach …

Trace Element Analysis Of Environmental And Clinical Materials Using Novel Instrumentation Based On X-Ray Fluorescence Spectrometry : New Capabilities For Public Health Laboratories, Kathryn G. Mcintosh

Legacy Theses & Dissertations (2009 - 2024)

X-ray fluorescence (XRF) spectrometry is a well-established analytical technique for determining the elemental content of many different materials. XRF has long been used for public health applications, particularly for identifying lead-based paint hazards. The primary advantage of XRF over other atomic spectrometric techniques is that it is nondestructive. In addition, little sample preparation is required, so results are obtained rapidly and at low cost. The principal aim of this study was to characterize the utility and reliability of current XRF instrumentation for use in the environmental health sciences. Interest in the use of XRF for detecting lead in children's toys …

Fractional Comparison Of Arson Accelerants Using Advanced Distillation, Sarah Clickner

Legacy Theses & Dissertations (2009 - 2024)

Detection of accelerants is often critical in proving a fire was intentional. Establishing a fire was intentionally set is not an easy task and hinges on the preservation of accelerant present in fire debris. Various accelerants have previously been studied using the advanced distillation method to get fractional composition information. The resulting fractions from advanced distillations were compared to evaporation and burn samples to determine if there were any similarities.

The Application Of Raman Spectroscopy As A Confirmatory Blood Test In The Presence Of Sodium Hypochlorite Cleaners In In Comparison With Presumptive Blood Tests, Aliea Anoshaa Afnan

Legacy Theses & Dissertations (2009 - 2024)

Popular presumptive tests for blood include: Luminol, tetramethylbenzidine (TMB), leucomalachite green (LMG), phenolphthalein, and Hemastix® [3]. These presumptive tests have been reviewed with respect to their sensitivity, specificity, and DNA degradation. In this study, the aforementioned presumptive tests were subjected to bloodstains deposited on cotton contaminated with all-purpose bleach and compared with Raman spectroscopy as an application of a confirmatory blood test. Samples were tested for interference with the all-purpose bleach to determine the selectivity of the presumptive tests. Tetramethylbenzidine, leucomalachite green, and phenolphthalein all yielded inconclusive results when applied to a contaminated sample. Luminol and Hemastix® yielded a positive …

Amyloid Fibril Polymorphism : Structure, Supramolecular Chiraliy And Spontaneous Interconversion, Dzmitry Kurouski

Legacy Theses & Dissertations (2009 - 2024)

Specific protein aggregation has been linked to more than 25 severe human maladies including prion, Alzheimer's, and Parkinson's diseases. These important malfunctions are often referred to as 'conformational' disorders and result from the conversion of a normal isoform of a protein into a specific b-sheet rich polymeric amyloid form. This work elaborates a comprehensive characterization of amyloids and dedicated to the investigation of the fibril polymorphism using advanced microscopic tools, such as Atomic Force and Scanning Electron microcopies, together with several vibrational spectroscopy techniques, such as Raman, Infrared and Vibrational Circular Dichroism. A new type of protein folding-aggregation phenomenon, spontaneous …