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University of Arkansas, Fayetteville

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Articles 1351 - 1380 of 2433

Full-Text Articles in Physical Sciences and Mathematics

Proportionality Of Population Descriptors Of Metacercariae Of Clinostomum Marginatum In The Orobranchial Cavity Of Black Bass (Micropterus Spp.) From Arkansas Ozark And Ouachita Streams, J. J. Daly Sr. Jan 2014

Proportionality Of Population Descriptors Of Metacercariae Of Clinostomum Marginatum In The Orobranchial Cavity Of Black Bass (Micropterus Spp.) From Arkansas Ozark And Ouachita Streams, J. J. Daly Sr.

Journal of the Arkansas Academy of Science

In a previous study of Clinostomum marginatum metacercariae in Micropterus dolomieu, I reported that the population parameters of mean abundance, standard deviation, maximum abundance, mean intensity and mean intensity standard deviation were proportional between the total population and the orobranchial numbers for 16 locations in Arkansas Ozark and Ouachita streams. This allowed an assessment of the parasite populations by only examining the mouth and gill areas without sacrificing a valued sports fish. The present study examined the same orobranchial parameters utilizing correlation and descriptive statistics to determine if proportionality also existed between the different localities. I have now included an …


Distribution, Habitat Preference, And Status Of The Ditch Fencing Crayfish, Faxonella Clypeata (Hay) (Decapoda: Cambaridae), In Arkansas, H. W. Robison, C. T. Mcallister Jan 2014

Distribution, Habitat Preference, And Status Of The Ditch Fencing Crayfish, Faxonella Clypeata (Hay) (Decapoda: Cambaridae), In Arkansas, H. W. Robison, C. T. Mcallister

Journal of the Arkansas Academy of Science

The ditch fencing crayfish, Faxonella clypeata (Hay), is a common and widespread crayfish that inhabits roadside ditches, intermittent first-order streams, shallow sloughs with heavy vegetation, and edges of swamps in Arkansas. Between 1997-2012, we made 55 collections of F. clypeata in 34 counties throughout eastern Arkansas, including 23 counties where F. clypeata had not been previously documented. At most of these locations within the West Gulf Coastal and Mississippi Alluvial Plain provinces, F. clypeata was found to be a locally abundant crayfish. With regard to conservation status, F. clypeata should be considered as “Currently Stable” due to its widespread distribution …


Solid State Dye Sensitive Solar Cells Based On Zno Nanowire As The N-Type Semiconductor, S. Abdulalmohsin Jan 2014

Solid State Dye Sensitive Solar Cells Based On Zno Nanowire As The N-Type Semiconductor, S. Abdulalmohsin

Journal of the Arkansas Academy of Science

We fabricated solid state dye-sensitized solar cells with ZnO nanorods as the n-type material and polypyrrole as the p-type material. The ZnO nanorods were grown on indium-tin oxide (ITO) glass by electrochemical methods for one hour. Scanning electron micrographs of the ZnO nanowire (NW) indicated a length of about 1 micrometer and a diameter of approximately 100-200 nm for the nanorods. Polypyrrole deposited on ITO/ZnO NW/dye and the fabricated device of ITO glass/ZnO nanorods/dye/polypyrrole/Ag showed a power conversion efficiency of 1.29%.


Binary Star Light Curve And Model Of Tyc 3670-588-1 From Professional-Amateur Collaboration, A, J. W. Robertson, B. Mcmath, D. Waters, R. T. Campbell, G. Roberts Jan 2014

Binary Star Light Curve And Model Of Tyc 3670-588-1 From Professional-Amateur Collaboration, A, J. W. Robertson, B. Mcmath, D. Waters, R. T. Campbell, G. Roberts

Journal of the Arkansas Academy of Science

We present the orbital light curve and model system parameters of a newly discovered eclipsing binary star in the constellation of Perseus. Our professional-amateur astronomy collaboration between Arkansas Tech University (ATU), the Central Arkansas Astronomy Society (CAAS) and Whispering Pine Observatory, produced photometry in two wavelengths (Johnson V and R) in order to model the system for fundamental parameters with a binary modeling code. We determined that this binary system contains two F-type stars orbiting each other with a short orbital period and having the following characteristics for the two components: mass ratio (q ~ 0.92), temperatures (T1~ 7170 K, …


Study Of The Relation Between The Spiral Arm Pitch Angle And The Kinetic Energy Of Random Motions Of The Host Spiral Galaxies, A, I. Al-Baidhany, M. Seigar, P. Treuthardt, A. Sierra, B. Davis, D. Kennefick, J. Kennefick, C. Lacy, Z. A. Toma, W. Jabbar Jan 2014

Study Of The Relation Between The Spiral Arm Pitch Angle And The Kinetic Energy Of Random Motions Of The Host Spiral Galaxies, A, I. Al-Baidhany, M. Seigar, P. Treuthardt, A. Sierra, B. Davis, D. Kennefick, J. Kennefick, C. Lacy, Z. A. Toma, W. Jabbar

Journal of the Arkansas Academy of Science

In this work, we report a relation between the kinetic energy of random motions of the corresponding host galaxies and spiral arm pitch angles (Mdynσ2- P), (M*σ2- P) where Mdyn is the bulge dynamical mass, M* is bulge stellar mass, and σ is the velocity dispersion of the host galaxy bulge. We measured the spiral arm pitch angle (P) for a sample of Spitzer/IRAC 3.6-μm images of 54 spiral galaxies, estimated by using a 2D Fast Fourier Transform decomposition technique (2DFFT). We selected a sample of nearly face-on spiral galaxies and used IRAF ellipse to determine the ellipticity and major-axis …


Urban Stream Syndrome In A Small Town: A Comparative Study Of Sager And Flint Creeks, T. S. Wakefield Jan 2014

Urban Stream Syndrome In A Small Town: A Comparative Study Of Sager And Flint Creeks, T. S. Wakefield

Journal of the Arkansas Academy of Science

Utilizing rapid bioassessment procedures and aquatic physiochemical techniques, a three-year investigation of Sager and Flint creeks was completed. Bioassessment indices and physiochemical parameters of the 2 streams were compared and the effects of urbanization on both watersheds were assessed. Correlating data concerning land usage in both watersheds and alterations of both streams' geomorphology were also utilized to conclude that Sager Creek shows a higher degree of urban stream syndrome than Flint Creek.


Low Speed Current Bearing Anti-Force Waves, M. Hemmati, W. P. Childs, H. Shojaei, H. Morris Jan 2014

Low Speed Current Bearing Anti-Force Waves, M. Hemmati, W. P. Childs, H. Shojaei, H. Morris

Journal of the Arkansas Academy of Science

For theoretical investigation of electrical breakdown of a gas, we apply a one-dimensional, steady profile, constant velocity, three-component (electrons, ions and neutral particles) fluid model. Our fluid model consists of the equations of conservation of mass, momentum and energy, coupled with the Poison’s equation. The set of equations is referred to as the electron fluid dynamical equations (EFD). This investigation involves breakdown waves with a substantial current behind the wave front, and waves for which the electric field force on electrons is in the opposite direction of the wave propagation (anti-force waves – lightning return stroke). Therefore, the set of …


Forensic Investigation Of Mysql Database Management System, Andrew C. Lawrence Dec 2013

Forensic Investigation Of Mysql Database Management System, Andrew C. Lawrence

Computer Science and Computer Engineering Undergraduate Honors Theses

For various reasons, circumstances might arise in which an investigator, enlisting the help of a system administrator, needs access to an instance of MySQL that is password protected by an individual system user. If this password is unknown and the user is uncooperative or unavailable, alternative means must be utilized to gain access to the data stored within the program. Two main approaches will be explored, each with its pros and cons. In one case, the password can be bypassed entirely, granting the investigator unfettered access to the program data. The second method allows a narrower look at only some …


Assessing Trichloromethane Formation And Control In Algal-Stimulated Waters Amended With Nitrogen And Phosphorus, Clinton Mash Dec 2013

Assessing Trichloromethane Formation And Control In Algal-Stimulated Waters Amended With Nitrogen And Phosphorus, Clinton Mash

Graduate Theses and Dissertations

Nitrogen (N) and phosphorus (P) enrichments can stimulate algal growth in drinking water sources, which can cause increased production of disinfection byproduct (DBP) precursors. However, the effect of systematic N and P enrichments on DBP formation and control has not been adequately studied. In this work, we enriched samples from a drinking water source - sampled on April 5, May 30, and August 19, 2013 - with N and P to stimulate algal growth at N:P ratios covering almost five orders of magnitude (0.2-4,429). To simulate DBP-precursor removal processes at drinking water treatment plants (DWTPs), the samples were treated with …


Reservoir Management Techniques To Enhance Biological Productivity And Protect Water Quality, Ben Alan Thompson Dec 2013

Reservoir Management Techniques To Enhance Biological Productivity And Protect Water Quality, Ben Alan Thompson

Graduate Theses and Dissertations

Three reservoirs of similar size, watershed land use, and qualitative characteristics in northwest Arkansas, USA were selected to compare the effects of chemical fertilization and pulsed artificial-upwelling on whole-lake productivity, specifically primary production and phytoplankton biomass. Numerous water quality parameters were quantified over a two year period (2011-13) with the goal of understanding how each management technique would stimulate productivity. This experiment was the first step towards a larger goal to ultimately enhance sport fish production. The first year of monitoring occurred in 2011 and served as a control year for the three lakes. Treatments were initiated in two of …


Sedimentary Provenance Of The Wedington Member, Fayetteville Shale, From Age Relations Of Detrital Zircons, William Tyson Cains Dec 2013

Sedimentary Provenance Of The Wedington Member, Fayetteville Shale, From Age Relations Of Detrital Zircons, William Tyson Cains

Graduate Theses and Dissertations

U-Pb geochronology of detrital zircons collected from the Chesterian Wedington Sandstone allows interpretation of sediment provenance and dispersal patterns in the southern midcontinent during the Late Mississippian. Detrital zircons analyzed from six samples of Wedington Sandstone yielded a final result of 565 concordant analyses used for interpretation. Results are plotted as Probability-Density Plots to interpret the spectrum of ages. Significant peaks occurred at 350-500 Ma, 950-1250 Ma, 1300-1500 Ma, 1600-1800 Ma, 1800-2300 Ma, and >2500 Ma. These peaks are interpreted as sourced by crystalline rocks within the Laurentian craton from Taconic-Acadian, Grenville, Midcontinent Granite-Rhyolite, Yavapai-Mazatzal, Paleoproterozoic, and Superior Provinces. The …


Assessing The Impact Of Chlorine Residual On Trihalomethane And Haloacetonitrile Formation Under Chlorination And Chloramination Disinfection Regimes, Thien Duc Do Dec 2013

Assessing The Impact Of Chlorine Residual On Trihalomethane And Haloacetonitrile Formation Under Chlorination And Chloramination Disinfection Regimes, Thien Duc Do

Graduate Theses and Dissertations

A disinfection byproduct (DBP) formation potential (FP) test can be used to indirectly measure the concentration of DBP precursors in natural waters, permitting assessment of various DBP-related treatment processes and control strategies. While these tests require a 7-day chlorine residual (CR) between 3-5 mg L-1 as Cl2, it is not well known if this recommended residual corresponds to the true DBPFP (i.e., the maximum concentrations) for trihalomethanes (THMs) and haloacetonitriles (HANs). In this study, THMs and HANs were quantified as a function of CR under three common disinfection regimes: (1) free chlorine at pH 7.0 (FC7), (2) …


Bacterially-Mediated Formation Of Rock Coatings In Kärkevagge, Swedish Lapland: A Mineralogical And Micro-Environmental Analog For Mars, Cassandra L. Marnocha Dec 2013

Bacterially-Mediated Formation Of Rock Coatings In Kärkevagge, Swedish Lapland: A Mineralogical And Micro-Environmental Analog For Mars, Cassandra L. Marnocha

Graduate Theses and Dissertations

The search for past or present life on Mars is, for now, limited to surface environments. An often neglected surface environment that could have served as an abode for life and could presently preserve evidence of that life is that of rock coatings. Rock coatings are mineral accretions on rock surfaces. On Earth, they are widespread and occur with considerable chemical diversity. There is growing evidence for a biotic role in their formation on Earth, particularly with respect to rock varnish. As a result, rock varnish has become a target of astrobiological interest on Mars, where varnish-like coatings have been …


Consumer Adoption Of Health Information Systems, Sankara Subramanian Srinivasan Dec 2013

Consumer Adoption Of Health Information Systems, Sankara Subramanian Srinivasan

Graduate Theses and Dissertations

At nearly 18 percent of the country's GDP, the U.S. healthcare industry continues to wrestle with growing cost and a quality of care that does not match the increased spending. The dominant focus to date has been on promoting Health IT (HIT) system implementation and digitizing health records at the provider's end, with scant attention to the role of the patient in the healthcare process. The source of inefficiency in the healthcare system is not only on account of shortcomings at the provider's end but also due to non-compliance (such as failing to adhere to medication advice and follow-up visits) …


Long-Term Residue And Water Management Effects On Soil Respiration And Soil Aggregate Stability In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Sharon Faye Smith Dec 2013

Long-Term Residue And Water Management Effects On Soil Respiration And Soil Aggregate Stability In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Sharon Faye Smith

Graduate Theses and Dissertations

Sustainability in agriculture is paramount to assuring continued production from our most naturally fertile soils. Storing carbon (C) in soil as organic matter through sustainable agricultural management practices can both remove atmospheric C and improve soil quality. The objective of this study was to evaluate the long-term effects of water management (irrigation and dryland), residue management [burn and no-burn, conventional (CT) and no-tillage (NT)] and residue/fertility level (high and low) on soil respiration and aggregate stability in a wheat- (Triticum aestivum L.) soybean [Glycine max (L.) Merr.], double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta …


Workforce Preparedness Of Information Systems Students: Perceptions Of Students, Alumni, And Employers, Susan Bristow Dec 2013

Workforce Preparedness Of Information Systems Students: Perceptions Of Students, Alumni, And Employers, Susan Bristow

Graduate Theses and Dissertations

Employers of newly hired higher education graduates report their new workforce is not prepared. Further research was required to discover insights to the workforce readiness gap. This concurrent mixed methods study explored what competencies influenced employer's perceptions of the work-readiness of Information Systems (ISYS) undergraduate students and discovered ISYS graduates' and current ISYS students' perceptions of their work-readiness. Participants consisted of a convenience sample including 69 ISYS program upperclassmen, 20 ISYS program alumni, and 8 employers of the ISYS program graduates. ISYS program alumni completed an online Qualtrics survey to measure the participants' perception of their workforce preparedness. ISYS program …


Attitudes And Behaviors In Online Communities: Empirical Studies Of The Effects Of Social, Community, And Individual Characteristics, Richard Kumi Dec 2013

Attitudes And Behaviors In Online Communities: Empirical Studies Of The Effects Of Social, Community, And Individual Characteristics, Richard Kumi

Graduate Theses and Dissertations

Online communities and communities of practice bring people together to promote and support shared goals and exchange information. Personal interactions are important to many of these communities and one of the important outcomes of personal interactions in online communities and communities of practice is user-generated content. The three essays in the current study examines behavior motivation in online communities and communities of practice to understand how Social and personal psychological factors, and user-generated influence attitudes, intentions and behaviors in online communities.

The first essay addresses two research questions. First, how does Social capital influence exchange and combination behaviors in online …


A Solar-Powered And Multi-Tiered Mesh Node For A Portable In Situ Emergency Response System, Adam Matthews Dec 2013

A Solar-Powered And Multi-Tiered Mesh Node For A Portable In Situ Emergency Response System, Adam Matthews

Graduate Theses and Dissertations

The aftermath of a natural disaster is typically characterized by lack of a reliable medium for dissemination of information to survivors. Current state-of-the-art emergency response systems rely on satellite radio-enabled devices, but survivors, unlike first responders, do not have access to such devices. To mitigate this problem, we present PERPETUU a solar-powered portable GIS microserver. The microserver node can be deployed in a disaster scene, and can serve maps to survivors viewable on browsers of off-the-shelf mobile systems. A key innovation in the design of the PERPETUU node is a multi-tiered hardware architecture-the system combines a low-power micro-controller, a medium-power …


Quantitative Trait Loci Associated With Waterlogging Tolerance In A Soft Red Winter Wheat Mapping Population, Diana Carolina Ballesteros Benavides Dec 2013

Quantitative Trait Loci Associated With Waterlogging Tolerance In A Soft Red Winter Wheat Mapping Population, Diana Carolina Ballesteros Benavides

Graduate Theses and Dissertations

Waterlogging is caused when water stays superficially in the soil for an extended period of time, creating an anaerobic environment which decreases plant growth and grain yield at maturity. Despite the impact of waterlogging on wheat production both globally and in the southeastern U.S., very little is known about the genetic control of waterlogging tolerance in wheat. The objective of this study was to determine the amount of genetic variation for vegetative stage waterlogging tolerance present within a wheat recombinant inbred line (RIL) population and to identify quantitative trait loci (QTL) associated with tolerance and productivity. Experiments were carried out …


Conceptual, Impact-Based Publications Recommendations, Ann Smittu Joseph Dec 2013

Conceptual, Impact-Based Publications Recommendations, Ann Smittu Joseph

Graduate Theses and Dissertations

CiteSeerx is a digital library for scientific publications by computer science researchers. It also functions as a search engine with several features including autonomous citation indexing, automatic metadata extraction, full-text indexing and reference linking. Users are able to retrieve relevant documents from the CiteSeerx database directly using search queries and will further benefit if the system suggests document recommendations to the user based on their preferences and search history. Therefore, recommender systems were initially developed and continue to evolve to recommend more relevant documents to the CiteSeerx users. In this thesis, we introduce the Conceptual, Impact-Based Recommender (CIBR), …


Developing A Presumptive Test For Select Synthetic Cannabinoids, Carrie Snyder Dec 2013

Developing A Presumptive Test For Select Synthetic Cannabinoids, Carrie Snyder

Graduate Theses and Dissertations

Synthetic cannabinoids (SC's) began to gain popularity around the world in 2009. Since then, many of the compounds have been outlawed and methods developed to detect them and their metabolites using mass spectrometry. Our work investigated the possibility of developing a colorimetric presumptive test. The SC JWH-019 was synthesized and its ketone targeted as a possible reaction site. Many SC's contain ketones and thus a reaction at this site would be applicable to many of the compounds. Since JWH-019 is costly and time consuming to synthesize, much of the experimental work was done using benzophenone (BP). BP contains a diaryl …


A Bandwidth-Conserving Architecture For Crawling Virtual Worlds, Dipesh Gautam Dec 2013

A Bandwidth-Conserving Architecture For Crawling Virtual Worlds, Dipesh Gautam

Graduate Theses and Dissertations

A virtual world is a computer-based simulated environment intended for its users to inhabit via avatars. Content in virtual worlds such as Second Life or OpenSimulator is increasingly presented using three-dimensional (3D) dynamic presentation technologies that challenge traditional search technologies. As 3D environments become both more prevalent and more fragmented, the need for a data crawler and distributed search service will continue to grow. By increasing the visibility of content across virtual world servers in order to better collect and integrate the 3D data we can also improve the crawling and searching efficiency and accuracy by avoiding crawling unchanged regions …


Hydrogeology And Chemical Characterization Of Hydrocarbon In Domestic Water Wells, Rancho Villa Subdivision, Rogers, Arkansas, Janelle Renee Sherman Dec 2013

Hydrogeology And Chemical Characterization Of Hydrocarbon In Domestic Water Wells, Rancho Villa Subdivision, Rogers, Arkansas, Janelle Renee Sherman

Graduate Theses and Dissertations

This project is centered on the Rancho Villa community in Rogers, Arkansas where several residents have had hydrocarbon contamination in their domestic water wells. The goal of this project was to understand the hydrogeology in the study area, characterize the contaminant chemically, and determine the source of the contaminant. The hydrogeology of the area was determined from previous theses. Seventeen samples were taken from the wells in the Rancho Villa community; each sample was analyzed for geochemical parameters and by Gas Chromatography/Mass Spectrometry (GC/MS) for organic compounds analysis. Four of the 17 samples had a visible non-aqueous layer of hydrocarbon …


Infrared Spectra Analysis Of Thermally Altered Iron Phyllosilicates And The Implications For Mars, William Thomas Bryan Dec 2013

Infrared Spectra Analysis Of Thermally Altered Iron Phyllosilicates And The Implications For Mars, William Thomas Bryan

Graduate Theses and Dissertations

This study looks at two iron-rich phyllosilicates, which may be present on Mars. The minerals, greenalite and hisingerite, are rich in iron-II and iron-III, respectively. Small samples (~0.40 grams) of each mineral were crushed and heated in a Lindberg Tube Oven for approximately twenty-four hours at temperatures selected to mimic lava flows and impact events. Following heating, each sample was placed in a Fourier Transform Infrared (FT-IR) spectrometer to collect the near- and mid-infrared spectra. The spectra allowed for these terrestrial analogs to be analyzed with regards to how their structure breaks down with increasing temperature. The samples' colors were …


Assessment Of The Predictive Reliability Of A Swat Flow Model And The Evaluation Of Runoff Generation And Bmp Effectiveness In A Shale-Gas Impacted Watershed Using A Modeling Approach, Kwasi Asante Dec 2013

Assessment Of The Predictive Reliability Of A Swat Flow Model And The Evaluation Of Runoff Generation And Bmp Effectiveness In A Shale-Gas Impacted Watershed Using A Modeling Approach, Kwasi Asante

Graduate Theses and Dissertations

In order to ensure a harmonious harness of shale-gas resources while ensuring minimal damage to the environment, it is imperative that studies to conduct to inform various aspects of managing the environment. This includes the development of reliable hydrologic models to inform in decisions concerning water and the environment.

The first objective of this study was to evaluate the predictive reliability of the Soil and Water Assessment Tool (SWAT) model based on respective methods of LULC data classification and data type spatial resolution. Results showed that the high-resolution data classified with object-oriented image method does not provide any significant advantage …


Microfluidics Guided By Redox-Magnetohydrodynamics (Mhd) For Lab-On-A-Chip Applications, Vishal Sahore Dec 2013

Microfluidics Guided By Redox-Magnetohydrodynamics (Mhd) For Lab-On-A-Chip Applications, Vishal Sahore

Graduate Theses and Dissertations

Unique microfluidic control actuated by simply turning off and on microfabricated electrodes in a small-volume system was investigated for lab-on-a-chip applications. This was accomplished using a relatively new pumping technique of redox-magnetohydrodynamics (MHD), which as shown in this dissertation generated the important microfluidic features of flat flow profile and fluid circulation. MHD is driven by the body force, FB = j × B, which is the magnetic part of the Lorentz force equation, and its direction is given by the right hand rule. The ionic current density, j, was generated in an equimolar solution of potassium ferri/ferro cyanide by applying …


Environmental Literacy Of Sixth Grade Students In Arkansas: Implications For Environmental Education Reform, Lisa Suzanne Wood Dec 2013

Environmental Literacy Of Sixth Grade Students In Arkansas: Implications For Environmental Education Reform, Lisa Suzanne Wood

Graduate Theses and Dissertations

Environmental education must be better integrated into K-12 curriculum to advance environmental literacy. Producing a citizenry that can understand and address the complex environmental issues facing the world today and in the future is essential to sustainable life on this planet.

Using the Middle School Environmental Literacy Survey, 6th grade students across Arkansas were surveyed to obtain a baseline measure of environmental literacy based on the four domains of environmental literacy included in the survey; ecological knowledge, environmental affect, cognitive skills, and behavior. Individual domain scores were combined into a composite environmental literacy score. Results were then compared to the …


Steady-State Switching And Dispersion/Absorption Spectroscopy Of Multistate Atoms Inside An Optical Ring Cavity, Jiteng Sheng Dec 2013

Steady-State Switching And Dispersion/Absorption Spectroscopy Of Multistate Atoms Inside An Optical Ring Cavity, Jiteng Sheng

Graduate Theses and Dissertations

This thesis mainly focuses on the experimental investigations of electromagnetically induced transparency (EIT) related phenomena in various systems involving multilevel atoms inside an optical ring cavity. Semiclassical methods, e.g. density-matrix equations, are used through out this thesis to simulate the experimental results. First, the cavity transmission spectrum can be significantly modified when multilevel atoms are placed inside an optical ring cavity. Such coupled atom-cavity systems are well explained by the intracavity dispersion/absorption properties. Specifically, three-level lambda-type, four-level N-type and double-lambda-type atoms inside an optical ring cavity are investigated by examining their cavity transmission spectra. Second, optical multistability (OM) has been …


Towards The Total Synthesis Of Antascomicin B. Efforts To Construct The C1-C21 Fragment, Juliette Rivero-Castro Dec 2013

Towards The Total Synthesis Of Antascomicin B. Efforts To Construct The C1-C21 Fragment, Juliette Rivero-Castro

Graduate Theses and Dissertations

Antascomicin B is a macrolide isolated from a strain of Micromonospora. It possesses structural similarities to FK506 and rapamycin and exhibits potent binding ability to FKBP12. Recent reports suggest that small molecule ligands of FKBP12 possess potent neuroprotective and neurodegenerative properties in mouse models of Parkinson's disease. Our approach to the C1-21 fragment of antascomicin B involves an asymmetric amino-Claisen rearrangement originally developed by Tsunoda et al.35 report the scalability of the preparation and rearrangement of an allylic amide possessing a silyloxy group at the terminal position of the alkene. The Tsunoda-Claisen rearrangement uses inexpensive (S)-α-methylbenzylamine as the chiral …


Monodentate, Bidentate And Photocrosslinkable Thiol Ligands For Improving Aqueous Biocompatible Quantum Dots, Hiroko Takeuchi Dec 2013

Monodentate, Bidentate And Photocrosslinkable Thiol Ligands For Improving Aqueous Biocompatible Quantum Dots, Hiroko Takeuchi

Graduate Theses and Dissertations

Water-soluble Quantum Dots (QDs) are highly sensitive fluorescent probes that are often used to study biological species. One of the most common ways to render QDs water-soluble for such applications is to apply hydrophilic thiolated ligands to the QD surface. However, these ligands are labile and can be easily exchanged on the QD surface, which can severely limit their application. As one way to overcome this limitation while maintaining a small colloidal size of QDs, we developed a method to stabilize hydrophilic thiolated ligands on the surface of QDs through the formation of a crosslinked shell using a photocrosslinking approach. …