Understanding how silvicultural treatments and changes in the forest resource will affect wood quality characteristics, including heartwood natural durability, is a critical need for forest managers. Because heartwood properties can be affected by environmental disturbances, including silvicultural practices used to grow trees faster, we need to know if increased growth...
Thermal stabilization of chlorophyll and anthocyanin on pear peels during thermal process was investigated in this study. The green color of peels-on thermally processed (canned) pears was successfully retained by complexation of magnesium-free chlorophyll with zinc ions, and the red pigments were stabilized through anthocyanin-stannous complexation and polymerization of pear...
The development of a transient electric birefringence (TEB) apparatus for macroparticle characterization is herein discussed. The experimental difficulties encountered were related largely to poor data resolution. Misalignment and strain birefringence in optical components further complicated results. Improved data digitization methods were developed, and precise mathematical models were derived in order...
Halogenated Polycyclic Aromatic Hydrocarbons (X-PAHs) are ubiquitous contaminants that are thought to be generated by processes such as chemical industries and incomplete combustion, including waste incineration and electronic waste (e-waste) burning. X-PAHs are a concern for environmental and human health because they are toxic, mutagenic, and are expected to be...
Commercial methodologies for producing fungal pigments are of worldwide interest due to the desire to move away from synthetic dyes. Chlorociboria species and Scytalidium species have been reported to produce sufficient yields of pigments for commercial production and have attracted special attention because of their use in spalted wood applications....
The “why” of any situation is one of the most important questions to ask. Inventors have ideas every day. Some ideas are the brilliant ideas that lead to a better tomorrow. To protect these ideas, inventors turn to patents, a governmental grant of the right to stop others, for a...
American hop growers have historically dried hops in the range of 140-155°F/ 60-68°C using deep bed kilns (24 – 32 inches/ 60 – 81 cm), but over the last 10 years they have shifted to lower temperatures (125 -135 °F/ 52 – 57°C) for drying new American aroma cultivars. Reduced...
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants and are mostly products of the incomplete combustion of organic material. PAHs are often found in environmental samples as a complex mixture of isomers. In addition, the same sources that produce complex PAH mixtures also produce other poorly characterized mixtures of organic compounds,...
Beer is one of the most extensively consumed beverages world-wide and it is almost always brewed with hops (Humulus lupulus, L.). Hops provide beer with bitterness, aroma, flavor and texture and also enhance specific beer properties such as foam stability, clarity (colloidal stability), color, flavor stability and microbial stability. Hops...
Used Nuclear Fuel (UNF) contains transuranic (TRU) elements and numerous fission products as a result of the uranium fission process and neutron activation that occur in commercial light water power reactors. Recent environmental and nuclear proliferation concerns have spawned the development of advanced reprocessing techniques to close the nuclear fuel...
Dendrimers are nanoscale macromolecules that have highly branched, core-shell structures. Higher generation dendrimers have close-packed peripheral functional groups and a hollow interior. The chemistry of the core and the terminal functionalities can be tailored according to the specific application. These structural characteristics provide room for the design of dendrimers to...
Novel synthetic strategies are developed to prepare new intercalation compounds and nanocomposites with several layered hosts (NiPS₃, Na-montmorillonite, MoS₂ and MoO₃). In these products, alkali metals are ionic intercalates and linear polymers, dendrimers or amines act as co-intercalates. In addition to new synthetic approaches, new structures are identified and characterized....
The emerging field of nanotechnology strictly requires the micro-scaling of the available separation technology and the design of novel devices for separations of molecules of interest. The separation of proteins and nanoparticles is challenging due to their relatively large size, non-specific adherence to surfaces and instability in many solvents.
This...
Contact of blood with the surfaces of synthetic materials is associated with spontaneous protein adsorption, initiating platelet aggregation, the coagulation cascade, and the eventual development of a stable clot. Current therapy to inhibit implant-induced thrombosis is life-long administration of systemic anticoagulants. An alternative to the systemic administration of anticoagulant drugs...
Protein adsorption on blood contacting medical devices usually causes fouling and failure, and may promote clotting and undesirable immune responses. Hydrophilic polymer coatings in a dense, pendent “brush” conformation can resist protein adsorption on the surface while increasing biocompatibility. Such coatings can also be used to immobilize a variety of...
The fusion reaction ²⁰⁸Pb (⁵⁰Ti, xn) ²⁵⁸⁻x Rf (x = 1-3) was studied to determine PCN (probability that the mononucleus system evolves to form a compound nucleus inside the fission saddle point) and to establish the value of Wsur (survival probability) for the given reaction experimentally. The fission excitation function...
Prevention of marine biofouling is vital to the survivability and performance of ships, buoys, and wave energy devices. Coatings that contain metal biocides are currently used to prevent marine biofouling. These coatings have a limited lifetime and are under environmental scrutiny. As a result, it is necessary to research and...
There is significant interest in harnessing the biosynthetic capacities of photosynthetic diatom microalgae for the production of unique bioinspired nanomaterials. Specifically, this research focuses on understanding the photoluminescent properties of diatom biosilica and β-chitin nanofiber production in diatoms. Diatoms are single-celled microalgae that possess intricately patterned biosilica shells called, frustules....
Miniaturized and portable microfluidic analytical platforms have been widely explored in the broad field of chemical analysis. The concept of microfluidics offer a number of important advantages, including low reagent consumption, low-cost detection, high sample throughput, and shorter analysis time. Semiconductor nanocrystals or quantum dots have been extensively utilized in...
Science inquiry is central to the science education reform efforts that began in the early 1990's. It is both a topic of instruction and a process to be experienced. Student engagement in the process of scientific inquiry was the focus of this study. The process of scientific inquiry can be...
Due to a number of disadvantages associated with the use of antibodies as
affinity stationary phases, researchers have recently began to explore the use of RNA
and DNA aptamers for use as affinity stationary phases. These molecules have been
shown to be a viable choice for applications in many methods...
The Micralyne microfluidic toolkit (μTK) was an instrument built by Micralyne in the early 2000’s. It was built for electrophoresis and has a sensitive laser-induced fluorescence detection system. The updates to the system were upgrading the control GUI from running in LabVIEW 5 (Windows XP, 2000) to LabVIEW 2012 (Windows...
This report details preliminary studies towards the development of a microfluidic
sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal
transduction. The device consists of a microwave circuit in which a slotline and a coplanar
waveguide are integrated with a biochemically activated sensor area. The magnetic beads...
Full Text:
@eecs.oregonstate.edu,
Oregon State University
Remcho*, Vincent
Department of Chemistry, Vincent.Remcho
This report details preliminary studies towards the development of a microfluidic
sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal
transduction. The device consists of a microwave circuit in which a slotline and a coplanar
waveguide are integrated with a biochemically activated sensor area. The magnetic beads...
Full Text:
.
Vincent T. Remcho received his BS in biochemistry in 1989 and his Ph.D. in chemistry
(with Prof. Harold
This report details preliminary studies towards the development of a microfluidic
sensor that exploits ferromagnetic resonance, excited in magnetic bead labels, for signal
transduction. The device consists of a microwave circuit in which a slotline and a coplanar
waveguide are integrated with a biochemically activated sensor area. The magnetic beads...
Chemical synthesis of oligonucleotides is a widely used tool in the field of biochemistry. Several methods for gene synthesis have been introduced in the growing area of genomics. In this paper, a novel method of constructing dsDNA is proposed. Short (28-mer) oligo fragments from a library were assembled through successive...
This dissertation describes the racemic and enantioselective synthesis cavicularin. Cavicularin is a macrocyclic bisbibenzyls family member natural product. It has been an attractive synthetic target due to its intriguing structure: the macrocyclic core imparts sufficient strain on the system to force one benzene rings to adopt a boat-shaped conformation, out...
High Performance Liquid Chromatography-Mass Spectrometry coupled with filtration, centrifugation, and other common sample preparation techniques offers a rapid and robust method for separating and quantifying propofol, a commonly used anesthetic, from human blood and its synthetic analogs. Method development is important for not only optimizing separation and quantification for a...
WLBU2 is an engineered cationic amphiphilic peptide that targets Gram-positive and Gram-negative bacteria, and envelopes endotoxin while avoiding other cell types. The exact mechanism of how WLBU2 targets, binds, and disrupts bacterial cell membranes is still not completely known. Thus, the overall goal of this investigation is to determine the...
New graphite intercalation compounds (GICs) containing N,N-n-alkyl substituted pyrrolidinium cation intercalates (Py[subscript n.m], n, m = alkyl chain lengths) are obtained via cationic exchange from stage-1 donor-type GIC [Na(ethylenediamine)₁.₀]C₁₅. Powder X-ray diffraction and thermogravimetric analyses are used to determine the GIC structures and compositions. [Py₄.₈]C₄₇·0.71DMSO and [Py₈.₈]C₄₈ with intercalate monolayers...
In a search for designed materials that mimic those found in biological systems, combining polymers with inorganic materials in sol-gel chemistry processes has gained momentum in the research world since the 1990's. This work methodically investigated the properties of several related polymer-SiO₂ hybrids prepared by a simple methodology that could...
Electrodeposition is a versatile polymer deposition technique to create nano-microscale materials using an electrical field generated from a charged droplet of solution and a grounded collector. Electrospinning or electrospraying can occur during electrodeposition, leading to the creation of nanofibers or bead-like materials depending on the process parameters. Photopolymerization of the...
Ion-selective polymeric optical sensors – ion optodes – are a promising alternative to ion-selective electrodes and fluorescent dyes for analytical and biological applications, e.g. extra- and intracellular measurements. They are non-toxic, highly selective robust probes for ionic fluxes monitoring.
A large-scale fabrication of ion optodes using a solvent displacement method...
The overall concept of reducing laboratory operations to a scale that fits on a single microfluidic chip has been an attractive area of research over the last several decades. Despite a surge in research, few commercial success stories have been written. Lab-on-a-chip technologies have the capability to be cost effective...
A novel method for detecting the peptidase activity of clinically relevant peptidases was investigated using solid-contact electrochemical polyion sensors under chronopotentiometric control. Complete instrumental control over ion-extraction was accomplished by incorporating a lipophilic electrolyte into the ion-selective membrane; the sensors had no intrinsic ion-exchange capabilities. The sensors were used to...
The purpose of this research was to investigate the optoelectronic properties of the
Ge doped biosilica, mainly focused on the photoluminescence (PL) properties of
diatom frustules of N. frustulum that contain metabolically inserted germanium
oxide produced by a two-stage photobioreactor cultivation process. In order to
explain the observed PL intensity...
A system of Photoactuated Droplet Microfluidics (PDM), in which a droplet of
fluid is moved by way of the manipulation of the wettability of a spiropyran
functionalized surface via irradiation with ultraviolet and visible light, was proposed. The
photochromic behaviors of several species of spiropyran were studied and a procedure...
Public attention and concern about per- and polyfluoroalkyl substances (PFASs) are increasing due to detection of PFASs in drinking water supplies, the environment, including remote locations, and wildlife and to the lowering of the federal health advisory levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in drinking water. Aqueous film-forming...
Chemical synthesis of oligonucleotides is a widely used tool in the field of biochemistry.
Several methods for gene synthesis have been introduced in the growing area of genomics.
In this paper, a novel method of constructing dsDNA is proposed. Short (28-mer) oligo fragments
from a library were assembled through successive...
Chemical synthesis of oligonucleotides is a widely used tool in the field of biochemistry.
Several methods for gene synthesis have been introduced in the growing area of genomics.
In this paper, a novel method of constructing dsDNA is proposed. Short (28-mer) oligo fragments
from a library were assembled through successive...
Full Text:
and an
Oligo Library
Sumate Pengpumkiat1, Myra Koesdjojo1, Erik R. Rowley2, Todd C. Mockler3, Vincent
The intriguing size- and shape dependent properties of nanoparticles have garnered recent attention in many science and engineering areas. When the particle size is in the nanometer size range, the material exhibits very different properties such as surface plasmon resonance (of gold nanoparticles) and superparamagnetism (of iron oxide nanoparticles). The...
Fungi from the genus Chlorociboria are known for their production of the blue-green quinonic pigment xylindein. Extracted xylindein has been the subject of investigations ranging from fabric dying to use a coloring agent in paint, and shows potential as an organic semiconductor in organic photovoltaics (OPVs) and other technologies. However,...
Cryopreservation of adherent cells may be advantageous for cell types that are difficult to
preserve in suspension or when it is necessary to preserve characteristics of the adherent cultured cells. Vitrification is a promising procedure for the preservation of adherent cells that prevents ice crystal formation and the resulting dissociation...
Novel ternary graphite intercalation compounds (GICs) of alkali metal cations
and a wide variety of amines have been synthesized by one-pot chemical syntheses.
Alkali metals studied includes Li, Na and K. The families of amines employed are nalkylamines,
branched alkylamines, and different structural isomers of diamines and
polyamines. Intragallery structures...
The challenges prompted by miniaturization of chromatographic systems have led scientists to explore new avenues in the synthesis of stationary phases. Packed capillary columns have found limited application in routine analysis due to a number of technical difficulties, most of which are attributable to the frits. New column designs insure...
This thesis presents a novel microlamination architecture that enables the large scale integration of valves into low cost micro energy and chemical systems via membrane entrapment. Polycarbonate layers embossed with microfluidic channels were bonded by ultrasonic welding of raised embossed protrusions that penetrate though the PDMS membranes. The bonding pressure...
For a number of reasons, miniaturization of chromatographic columns has been a general trend over the past three decades. Methods designed to enhance selectivity and efficiency can offer improved separation power and speed, expanding on the advantages of miniaturized columns. This dissertation describes novel approaches in this direction, focusing on...
Transient liquid-phase diffusion brazing is used in precision, hermetic joining applications as a replacement for diffusion bonding to reduce cycle times, reduce bonding pressure and improve yields. Studies showed that the interlayer used in diffusion brazing can be detrimental due to the use of melting point depressants (MPDs). The goal...
Novel donor-typed ternary graphite intercalation compounds (GICs) are synthesized and characterized containing (1) pyrrolidinium cations with DMSO co-intercalates; (2) alkali metal cations with crown ether co-intercalates; and (3) alkali metal cations with polyethylene glycol co-intercalates. Structural and compositional data are obtained for the stable products. A new ether-amine co-intercalate exchange...
Microchannel process technology (MPT) offers several advantages to the field of nanomanufacturing: 1) improved process control over very short time intervals owing to shorter diffusional distances; and 2) reduced reactor size due to high surface area to volume ratios and enhanced heat and mass transfer. The objective of this thesis...
Over the last decade, the miniaturization of analytical systems has become an increasingly important and interesting research area. Miniaturized systems offer many advantages, including reduced reagent and sample consumption, shorter analysis times, portability and disposability. This dissertation describes novel approaches in this direction, focusing on two areas: the miniaturization of...
New methods, sensors, and devices based on redox indicators were developed to
monitor redox conditions in anoxic and anaerobic laboratory systems and the subsurface
environment. The primary application was monitoring redox conditions
during the dechlorination of tetrachioroethene (PCE) to ethene (ETH) in packed
columns and microcosm bottles containing an enriched...
Microalgae has been under careful consideration as a sustainable feedstock for renewable fuel recently due to its year round production with high energy yields per unit area, reduced need for arable land, water treatment benefits with nutrient cycling, and minimal competition with the food industry. Despite of all these advantages,...
We have developed a compact micro total analysis system (μTAS) to serve as a platform for in-situ spectrophotometric water quality monitoring. Individual fluidic, optical, and electrical components were designed, developed, and characterized. These components were combined in both an integrated (single lithographic “chip-based” platform) and a modular manner. The microfluidic...
The development of micro total analysis systems (µTAS), also called “lab-on-a-chip”, or microfluidic analysis systems, is presented in this dissertation. Various research areas, covering subjects from magnetic particles synthesis to novel microchip fabrication techniques, are explored to develop a lab-on-a-chip system capable of performing magnetic bead-based bioassays. These devices are...
The objective of this thesis is to introduce and demonstrate a novel magnetic bead detector based on inductive detection at the ferromagnetic resonance (FMR) frequency for use in bio-sensing applications. Detection ability is demonstrated through theoretical arguments, numerical computer simulations, and experimental characterization of micro-fabricated detectors.
The detector is composed...
Radiation exposure to the brain can occur from a variety of events, including space missions, nuclear accidents, and clinical treatments. The effects of high dose radiation are well studied, but those of lower dosage are more elusive. Decline of memory and cognition is observed in patients exposed to low dose...
Low-dimensional electronic materials offer a platform to observe biological processes with unprecedented spatial and temporal resolution. Carbon nanotubes (CNTs) are the closest physical analog to an ideal 1D system and can be scaled and integrated into multiplexed electronic circuitry. The molecular structure of a CNT is also biocompatible, making them...
Wine taste and mouthfeel are essential factors that determine consumer acceptance, consumer preference, and wine quality. The three taste descriptors, sweet, sour, and bitter, are well understood and routinely appearing in wine sensory. In contrast, information related to mouthfeel sensations is still relatively limited. Winemakers have worked hard to craft...
A system to reversibly extract Pb²⁺ ions from aqueous solutions using spiropyran functionalized nanofibers was proposed. Spiropyrans are photochromic compounds which undergo a conformational change that alters their physical properties and makes Pb²⁺ binding possible upon irradiation with UV light (365 nm). Irradiation with green light (525 nm) reverses this...
The concept of reducing laboratory operations into microfluidic devices has been an attractive area of research for several decades. Due to several advantages of porous-media microfluidic devices including low mass, portability, power-free fluid transport, and the ability to store dried reagents in the porous structures, these devices show great promise...
A simple Janus-type membrane-based wicking microfluidic device fabricated on a polycaprolactone-filled glass microfiber membrane enables separation and collection of blood plasma or serum from whole blood. This device bridges the wicking and cut-capillary-based solution transport mechanisms in a single membrane. The initial portion of the device is fabricated using selective...
The materials Fe₂(Si,Ge)(S,Se)₄, Cu₃PS[subscript 4-x]Se[subscript x] (0 ≤ x ≤ 4), and Cu₃PxAs[subscript 1-x]S₄ (0 ≤ x ≤ 1) have been synthesized and studied as new earth-abundant absorbers for single and multijunction photovoltaic cells as well as solar fuel generation. The synthesis, single-crystal growth, and optical and electrical properties of...
The various solution-based processes, spin coating, inkjet printing, microreactor assisted nanoparticle deposition (MANDTM) and spin-successive ionic layer absorption and reaction (Spin-SILAR) were used to demonstrate thin film electronics and anti-reflective coatings. Several aspects of thin film transistors (TFTs) were tested including a range of temperatures, annealing atmosphere, and deposition methods....
Historically, brewers have used dry-hopping (a cold extraction of nonvolatile and volatile chemicals from hops into fermenting or finished beer) to increase the microbial stability and shelf life of their beer. As hoppy beer styles have gained in popularity over the last decade (2007-2017), the objective of dry-hopping has turned...
The influence of cultivar and maturity on polyphenolic composition and
antioxidant activity was investigated by UV-Visible spectrophotometry and
analytical high performance liquid chromatography (HPLC) in commercially
important blackberry cultivars and selections. The anthocyanin pigments changed
tremendously with ripening. Total anthocyanins increased from 74.7-317 mg/100g
fw from underripe to over ripe...
Two improvements to the established procedures for synthesis and response detection of ion-selective optical sensors (optodes) were introduced.
The first improvement addresses the drawback of organic dye (optode-localized chromoionophore) photobleaching. This positively impacts fluorescence response and allows for (1) direct measurement of hydrogen ion activity upon binding with the dye,...
Methane is a flammable gas that is the main component of natural gas. It is a highly potent greenhouse gas, and accounts for about 20% of greenhouse gas emissions. Methane is routinely flared in many industrial processes without harnessing any of its energy. The environmental impact and wasted energy potential...
A low, but significant, fraction of the carbohydrate portion of herbaceous biomass may be composed of fructose/fructosyl-containing components (“fructose equivalents”); such carbohydrates include sucrose, fructo-oligosaccharides, and fructans. Standard methods used for the quantification of structural-carbohydrate-derived neutral monosaccharide-equivalents in biomass are not particularly well suited for the quantification of fructose equivalents...
Proteins are essential to all biological systems. Proteins participate in numerous cellular processes by interacting with other proteins, other metabolites and membranes in a dynamic environment. Studying the structural and conformational properties of proteins in the solution phase is necessary to understand their protein folding and interaction dynamics. This research...
Novel donor-type graphite intercalation compounds (GICs) containing tetra-n-alkylammonium (TAA) cations have been synthesized by using both ion-exchange and electrochemical methods. Structural and compositional data of the resulting TAA-GICs are investigated by using powder X-ray diffraction (PXRD), one-dimensional electron density calculations, thermogravimetric and elemental analyses, and capillary zone electrophoresis (CZE). A...
The development of simple, rapid, and sensitive methods for thiophenol detection is of great importance in various fields, including environmental monitoring and food quality. Here, we present a novel approach for the colorimetric detection of thiophenols using gold nanoparticles (AuNPs) as the sensing platform. AuNPs aggregate in the presence of...
European hazelnut (Corylus avellana L.) is an important crop Oregon's Willamette Valley, producing 99% of the hazelnuts grown in North America and brings over US $60 million dollars to the region annually. Hazelnuts are rich in fiber and vitamins, as well in demand by consumers due to their popularity as...
Detection technique that proposed utilizing electrochemically controlled, reversible ion extraction into polymeric membrane in an alternating galvanostatic/ potentiostatic mode was introduced. This method is studied in detail to comprehend the advantages of the novel sensor (pulstrode) compared to the potentiometric ion selective electrode (ISE), studies included possible applications and limitations....
The spalting fungus Scytalidium cuboideum secretes a red pigment that produces naphthoquinonic crystals that are a photonic material candidate. The molecule can pack together in different configurations resulting in amazingly different optical properties. I developed a procedure (slowly evaporating the solvent) to preferentially grow two of these configurations, which have...
Since their discovery in the 1990s, the great potential of carbon nanotubes (CNTs) has made them a focus of many research endeavors, including their application as components of biosensors. The inherent chemical "inertness" of CNTs makes their application to biosensing a challenge. It is necessary to "decorate" their surfaces to...
Transition metal oxides are an important class of materials for the wide variety optical, electrical, dielectric, magnetic, and thermal properties observed. Their unique structure-property relationships allow for property tuning and often provide insight into the fundamentals of chemistry. The work in this thesis was focused on the design, synthesis and...
Advances in energy technologies and electronics have typically occurred through either heightened performance or cost reduction. This dissertation explores both routes through a series of fundamental material studies that may contribute to the enabling of next generation devices. Solution based syntheses and deposition of chemical products offer a low cost...
Dielectrophoresis (DEP) is a separation method in which a non-uniform electric
field is used to induce a dipole moment in a suspended particle. If the polarization
of the particle is greater than that of the suspending medium, the particle will move
towards the region of higher field strength (positive DEP);...
When hops are added to beer, varying degrees of hoppy aroma persist in the finished beer as a result of a number of factors. Dry-hopping is a technique whereby hops are added to beer post-fermentation to leverage the maximum aroma potential of the hop essential oils while minimizing bitterness contribution...
The concept of reducing laboratory operations in scale such that they fit on a microfluidic chip has been met with great enthusiasm. Lab-on-a-chip devices promise to be cost effective to operate due to reduced reagent consumption, have the potential to offer shorter analysis times due to their short path lengths,...
Background: The Oregon Wrestling Weight Monitoring Program establishes the athlete’s minimum wrestling weight (MW) for the season. This program specifies the
wrestler’s maximum weight loss rate and was implemented in order to reduce
unhealthy weight-cutting behaviors commonly practiced by wrestlers. Aims: (1) To
compare differences in percent body fat (%BF)...
This thesis presents an approach to develop innovative methods for decontamination and surface protection applicable to naval nuclear ships and potentially, personnel, replacing antiquated techniques. To accomplish this goal, two products manufactured by CBI Polymers, LLC., DeconGel™ 1101 (1101) and a shampoo, DeconGel™ "prototype" (prototype), were tested.
The prototype was...
Heartwood can have properties that are distinct from sapwood,
including resistance to insect and microbial attack. Despite the practical
importance of heartwood formation in trees, a review of the literature revealed
that little was known about the effects of environmental factors on heartwood
quality or how variations in heartwood properties...
Capillary electrophoresis as a technique has many applications in a broad range of fields including forensics, environmental analysis, and biological analysis and as a separation method for samples such as oligonucleotides, peptides, proteins, and pharmaceuticals. The research conducted herein is for the antibiotic pharmaceutical ciprofloxacin HCl and three impurities. Sample...
Electrospinning and electrospray are both nano-scale material fabrication techniques, based on related phenomena of electrically charged fluid spray from a droplet of liquid. Material is dissolved in liquid, then a spray is generated by applying a high voltage, creating an electric field, between the fluid dispensing capillary and a grounded...
Dental plaque is one of the well-characterized biofilms in the human body. Oral bacterial species play vital roles in maintaining healthy bacterial homeostasis as well as causing oral infections. Many of the oral diseases are caused by opportunistic pathogens, and therefore, the bacterial metabolic activities become important in dictating their...
The general theme of this dissertation is the development of new analytical sensors to quantitatively study biological and environmental samples in aqueous and non-aqueous environments. A platinum ultramicroelectrode (UME) and a unique carbon-based pH microprobe were used to design a new SECM-based electrochemical bioassay. The Pt UME was used to...
ZnO nanowires (NWs) are good candidates for chemical sensing because of their high surface-to-volume ratio. In this work, ZnO nanobridge sensors were fabricated utilizing a novel method which uses carbonized photoresist (C-PR) as a nucleation layer. The use of C-PR allows simultaneous growth and integration of NWs to lithographically-defined features....
One post-transcriptional mechanism that regulates the progression of cancer and other diseases involves small 22-23 nucleotide sequences called microRNA (miR). Early detection of small changes in concentration of these biomarkers holds potential to diagnose diseases at their earliest stages. Use of current nucleic-acid based biosensors, like molecular beacons, for in...
It is often perceived that late maturity of grape gives a more complex aroma
profile to Pinot noir wine, however, there is little understanding of the basic flavor
chemistry of grape maturity on wine aroma. The aroma contributing compounds in
Pinot noir were first identified by aroma extract dilution analysis...
The focus of this study is to develop a general and low-cost solution-based
process to fabricate micro- and nano-structured semiconductors that are suitable
for electronics. This process uses simple metal halide precursors dissolved in a
solvent (organic or aqueous) and is capable of forming uniform and continuous
thin films via...
It is the responsibility of humans, as environmental stewards, to monitor our impact on the environment so that efforts can be made to remediate the effects of our actions and change behaviors. To better understand our environmental footprint, sensitive and simple analytical methods are needed to quantify the contaminants that...
Three analytical methods for determination of aroma compounds in alcoholic beverages were developed and validated. These methods are sensitive and reliable that can be applied to analyze volatile phenols, stale aldehydes as well as some highly volatile aromas in alcoholic beverages. In the first study, an ethylene glycol (EG) polydimethylsiloxane...
Over the last decade, the use of highly branched macromolecules, called dendrimers, is emerging. Polyamidoamine (PAMAM) dendrimers, in particular, have attracted high interest due to their unique properties, such as well-defined size, shape, and solubility in water. Our group, as part of an interdisciplinary team, is currently working on developing...
The general theme of this dissertation is the application of novel carbon based micro sensors with the scanning electrochemical microscopy (SECM). SECM allows positioning of the probe without touching the substrate while mapping the chemical parameters in 3D space above the substrate. The main focus of the dissertation is the...
State-of-the-art, high-resolution mass spectrometry techniques for acquisition of metabolomic and lipidomic data coupled with advanced computational methods provide new opportunities for interpreting large and complex datasets and comprehending the underlying biological processes of diseases. Both metabolomics and lipidomics strive to obtain comprehensive analyses of small molecules, i.e., metabolites and lipids,...
While fluorochemicals have been detected all over the world and in wastewater
treatment plants, the effect of wastewater effluent on the receiving waters has not been
evaluated. In the first study, the mass flow of fluorochemicals emanating from
wastewater treatment plants along the Glatt River in Switzerland was evaluated. The...