https://doi.org/10.33697/ajur.2009.001

Undergraduate Essay: Open Source Science

https://doi.org/10.33697/ajur.2009.002

Author(s):

Megan Schield and Douglas Armstrong

Affiliation:

Olivet Nazarene University, One University Avenue, Bourbonnais, Illinois 60914-2345 USA

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Molecular Distribution Behavior of Cyanine Dyes in Aqueous Solution

https://doi.org/10.33697/ajur.2009.003

Author(s):

David Baumann, Bryan Clark, Jared Garlick, and Hussein Samha

Affiliation:

Department of Physical Science, Southern Utah University, Cedar City, Utah 84720 USA

ABSTRACT:

The molecular distribution of the cyanine dye (5-chloro-2-[3-[5-chloro-3-(4-sulfobutyl)-2(3H)-benzothiazolylidine]-1-propenyl]-3-(4-sulfobutyl)-benzothiazolium hydroxide triethylamine salt, NK-3796) in aqueous solution was investigated using absorption and emission spectroscopy. Dimers of the dye are formed in concentrated solutions, while monomers dominate more diluted solutions. J aggregates are formed in solutions containing electrolytes such as sodium chloride, calcium chloride, and di-hydrogen ammonium phosphate. The dye readily forms J aggregates upon mixing with electrolyte. The J aggregates formation was followed spectroscopically by the appearance of a red-shifted narrow band centered at 653 nm in the absorption spectra. A similar shift is also observed in the emission spectra. The absorbance bandwidth is dependent on the charge of the cation of the electrolyte. This suggests different ground-state conformations for the J aggregates in solution.

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Material Point Method Investigations of Trauma to Fluids and Elastic Solids Due to Finite Barriers

https://doi.org/10.33697/ajur.2009.004

Authors and Affiliations:

J.L. Dean
Department of Aeronautical Engineering, Iowa State University, Ames, Iowa 50014 USA
M.W. Roth
Department of Physics, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

Paul A. Gray
Department of Computer Science, University of Northern Iowa, Cedar Falls, Iowa 50614-0507 USA

ABSTRACT:

A Material Point Method (MPM) algorithm is developed and utilized to investigate how the dynamics of (Langrangian) Navier-Stokes fluids as well as that of elastic solids is affected by trauma due to finite barriers. For the fluid simulations, material point particles are placed in a two dimensional pipe with various initial and boundary conditions and stationary perturbations to fluid flow. Results show that eddy currents are present not only in the wake of the perturbing object but are also responsible for disruption of laminar flow upstream from the barrier. An unfortunately relevant application for sudden finite trauma to an elastic solid involves simulations of an aircraft striking a large building under varying system conditions. The work presented here is introductory in nature; the potential ramifications and importance of continued study is discussed and emphasized.

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Anisotropic Properties of Sculptured Thin Films

https://doi.org/10.33697/ajur.2009.005

Author(s):

Drew Pulsifer, Andrew Jones and Tariq H. Gilani

Affiliation:

Department of Physics, Millersville University, P. O. Box 1002, Millersville, Pennsylvania 17551 USA

ABSTRACT:

The electrical anisotropy of Cr-Sculptured thin films has been studies as a function of growth angle of Cr columns on a glass substrate. A peak in resistivity anisotropy is found at growth angle of 72 ± 5^o.

https://doi.org/10.33697/ajur.2008.017

Educating Scientists During Hard Times

https://doi.org/10.33697/ajur.2008.018

Author(s):

C. C. Chancey

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

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A Distributional Approach to Conditionally Convergent Series

https://doi.org/10.33697/ajur.2008.019

Authors and Affiliations:

Gregory A. Ciccarelli
Schreyer Honors College, The Pennsylvania State University, 10 Schreyer Honors College, University Park, Pennsylvania 16802-3905 USA

Patrick Moylan
Physics Department, Abington College, The Pennsylvania State University, Abington, Pennsylvania 19001 USA

ABSTRACT:

Whether the car’s gas tank is filled up on Monday and the paycheck is deposited on Tuesday, or vice versa, the contribution of those two transactions to the checkbook’s final balance is the same. By the commutative property, order does not matter for the algebraic addition of a finite number of terms. However, for a super banker who conducts an infinite number of transactions, order may matter. If a series (sum of all transactions/terms) is convergent and the order of term does not matter, then the series is absolutely convergent. If a series is convergent but the order of terms does matter, then it is conditionally convergent. Georg Bernhard Riemann proved the disturbing result that the final sum of a conditionally convergent series could be any number at all or divergent. In two, three and higher dimensions, the matter is even worse, and such series with double and triple sums are not even well-defined without first giving sum interpretation to the (standard) order in which the series is to be summed, e.g., in three dimensions, summing over expanding spheres or expanding cubes, whose points represent ordered triples occurring in the summation. In this note we show using elementary notions from distribution theory that an interpretation exists for conditionally convergent series so they have a precise, invariant meaning.

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Evaluating α-Synuclein’s Interaction with Cellular Phospholipids and Potential Toxicity in Yeast Models for Parkinson’s Disease

https://doi.org/10.33697/ajur.2008.020

Author(s):

Lokesh Kukreja and Shubhik DebBurman

Affiliation:

Biology Department, Lake Forest College, 555 N. Sheridan Road, Lake Forest, Illinois 60045 USA

ABSTRACT:

Parkinson’s disease is a progressive neurodegenerative disease caused by the death of midbrain dopaminergic neurons. The misfolding and aggregation of α-synuclein plays a ruinous role in this disease, but how the protein becomes toxic is unclear. Using yeasts as model organisms for studying α-synuclein properties, our study explores the hypothesis that α-synuclein toxicity depends on plasma membrane phospholipid binding. First, using a chemical approach, we induced phospholipid synthesis in both fission and budding yeast with dimethyl sulfoxide (DMSO), a known inducer [1]. Instead of regulating α-synuclein-dependent toxicity, DMSO unexpectedly exerted its own toxicity in both yeasts, in addition to inducing a lethal morphology defect in budding yeast. Moreover, instead of inducing plasma membrane localization of α-synuclein in either yeast, DMSO altered α-synuclein localization in both yeasts into as-yet unidentified cytoplasmic structures. We speculate that some of these structures may be internal, membrane bound organelles. To test for membrane phospholipid binding specifically, α-synuclein localization was analyzed in a phosphatidylserine-deficient budding yeast strain. We observed no loss of plasma membrane localization, suggesting that other phospholipids may regulate such specificity to α-synuclein. Together, these related studies illustrate the usefulness of yeasts in evaluating genetic and environmental factors that regulate α-synuclein toxicity linked to Parkinson’s disease.

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Immune Function, Body Size, and Parasite Load in Lubber Grasshoppers

https://doi.org/10.33697/ajur.2008.021

Author(s):

Alex Kreuzer, Jinger Walrath, Meaghan Hirsch, and Olcay Akman (Department of Mathematics)

Dori Pitynski, Jason Jannot, and Steve Juliano (School of Biological Sciences)

Affiliation:

Illinois State University, Normal, Illinois 61790 USA

ABSTRACT:

Immunity is an important biological property of organisms that protects them from parasites. Similarly, body size is one of the most important biological traits because almost all biological processes, from the cellular to the ecosystem level, scale with body size. Our goal was to determine the correlation between body size and immune function in different populations of the eastern lubber grasshopper (Romalea microptera) which differ in body size. Field data was collected on grasshopper location, size (thorax and femur lengths), and immune function (measured by melanization response). In accordance with previous work, we found a significant body size cline among populations of south Florida grasshoppers: on average, small adult grasshoppers are found in western populations whereas large grasshoppers are found in eastern populations. However, we did not find a significant relationship between body size and one measure of immune function, either within or across these populations. Future work should be directed at understanding when body size and immune function might or might not be correlated.

https://doi.org/10.33697/ajur.2008.012

WALL-E in Real Life

https://doi.org/10.33697/ajur.2008.013

Author(s):

C. C. Chancey

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

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Survey of Nitrogen Isotopes of Lepomis macrochirus (Blue Gill) from Kentucky Lake Reservoir and Ledbetter Creek, Kentucky

https://doi.org/10.33697/ajur.2008.014

Author(s):

Rebecca M. Cripps and George W. Kipphut

Affiliation:

Department of Biological Sciences & Hancock Biological Station, Murray State University, Murray, Kentucky 42071 USA

ABSTRACT:

Previous research has shown stable isotope ratios of nitrogen in fish and other animals may vary depending on their food source. Ecologists have had some success in determining feeding and trophic relationships within an ecosystem using stable isotopic ratios. In this study, nitrogen stable isotopic ratios were measured in populations of Lepomis macrochirus (Blue Gill) in Kentucky Lake Reservoir and in a small tributary, Ledbetter Creek, in western Kentucky. The nitrogen isotopic ratios between these populations were statistically different. Even though fish are able to migrate freely between the two environments, the isotopic results suggest that the Lepomis macrochirus in Ledbetter Creek were spending enough time feeding in that environment to alter their isotopic signature. These results may lead to a better understanding of how Lepomis macrochirus utilize both stream and reservoir environments.

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Comparison of Biochemical and Chemical Digestion and Detection Methods for Carbohydrates

https://doi.org/10.33697/ajur.2008.015

Author(s):

Katie Miloski, Kelly Wallace, Ashley Fenger, Ellen Schneider, Kestas Bendinskas

Affiliation:

Department of Chemistry, State University of New York—Oswego, Oswego, New York 13126 USA

ABSTRACT:

There is a multitude of chemical and biochemical detection methods for sugars. Which ones would be most practical in an undergraduate laboratory setting? How to best detect non-reducing disaccharides? How to make such lab fun for students to perform? After trying several spectrophotometric methods, it was found that chemical detection by dinitrosalicylic acid and biochemical detection by hexokinase/glucose-6-phosphate dehydrogenase reagent are most appropriate. Sucrose, a non-reducing disaccharide was digested chemically with hydrochloric acid and biochemically with invertase. It was concluded that chemical detection and biochemical detection compliment each other. Chemical digestion method was preferred over the digestion by invertase. These methods were applied for testing the validity of sugar ingredients printed on drink labels as well as the measurement of sugar levels in ripening bananas at two different conditions. The comprehensive comparison of these methods and the detection of sugar concentrations in interesting samples might serve as a basis for an undergraduate chemistry laboratory.

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The Effects Hypergravity on the Morphology of Xenopus Embryos

https://doi.org/10.33697/ajur.2008.016

Author(s):

Rochelle Remus and Darrell Wiens

Affiliation:

Department of Biology, University of Northern Iowa, Cedar Falls, Iowa 50614-0421 USA

ABSTRACT:

Early amphibian development is sensitive to both reduced and elevated gravitational force. But later, following gastrulation and neurulation, a critical population of cells must migrate from the dorsal neural tube outward to destinations throughout the body where they differentiate into a wide variety of critical tissues including head cartilage. These cells, the neural crest cells, respond to extracellular cues and signals that guide migration and differentiation in an intricate process that may also be sensitive to altered gravity. We examined the effects of hypergravity on the migration of neural crest cells to form head skeleton cartilage, and on body size in Xenopus embryos. To investigate this we centrifuged embryos at 7G or 10G, from yolk plug stage (gastrulation) through five days of development to stage 45 when feeding begins. A control group was placed on the centrifuge. After centrifugation, the embryos were fixed, cleared and stained with Alcian Blue to reveal cartilage. We then captured images for analysis to obtain body and head cartilage measurements. We found that hypergravity retarded the growth of Xenopus embryos, possibly via increased load on the cardiovascular system. Surprisingly, it also resulted in significantly larger and more asymmetrical head cartilages, when corrected for body size, but it did not result in a significantly higher frequency of malformations. Our results support the likelihood that hypergravity inhibits body growth and perturbs the formation of neural crest derived head cartilage.

https://doi.org/10.33697/ajur.2008.006

Alternative Energies and Undergraduate Research

https://doi.org/10.33697/ajur.2008.007

Author(s):

C. C. Chancey

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

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A Graph Theoretical Approach to DNA Fragment Assembly

https://doi.org/10.33697/ajur.2008.008

Author(s):

Jonathan Kaptcianos

Affiliation:

Saint Michael’s College, Colchester, Vermont 05439 USA

ABSTRACT:

Built on prior work on sequencing by hybridization, fragment assembly is a newly explored method of determining whether or not a reassembled strand of DNA matches the original strand. One particular way to analyze this method is by using concepts from graph theory. By constructing data models based on these ideas, it is possible to come to various conclusions about the original problem regarding reassembled strands of DNA. In this paper we will detail this approach to DNA fragment assembly and present some related graph theoretical proofs in the process, including the BEST theorem. Further, we will explore the Eulerian superpath problem and its role in aiding fragment assembly, in addition to other recent applications of graph theory in the field of bioinformatics.

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Acetylation-Dependent Binding Analysis of the Yeast Gcn5 Bromodomain Protein

https://doi.org/10.33697/ajur.2008.009

Author(s):

Jesús Francisco Glaus Garzón, Christopher Kupitz, Joshua Bailey, and Martin Thompson

Affiliation:

Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931 USA

ABSTRACT:

The 439 amino acid yeast Gcn5 protein contains a C-terminal bromodomain, which is required for SAGA (Spt-Ada-Gcn5-Acetyltransferase) mediated nucleosomal acetylation and transcriptional coactivation. Bromodomains are acetyl-lysine binding modules found in many chromatin binding proteins and histone acetyltransferases. Recently, both in vivo and in vitro studies indicate that bromodomains are able to discriminate the acetylation state of lysine side-chains within histone proteins. Here, the cloning, expression and bioactivity of a recombinant bromodomain from the yeast Gcn5 protein is described. The bromodomain from Gcn5 was cloned from yeast genomic DNA enabling effective one-step purification by affinity chromatography. Steady-state fluorescence anisotropy was used to quantify the interaction of Gcn5 with acetylated histone H3. The present cloning, expression, and purification procedure enabled the preparation of large quantity and high yields of biologically active recombinant Gcn5 bromodomain for in vitro structure and function studies.

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Band Gap Energy in Silicon

https://doi.org/10.33697/ajur.2008.010

Author(s):

Jeremy J. Low, Michael L. Kreider, Drew P. Pulsifer, Andrew S. Jones and Tariq H. Gilani

Affiliation:

Department of Physics, Millersville University, P. O. Box 1002, Millersville, Pennsylvania 17551 USA

ABSTRACT:

The band gap energy Eg in silicon was found by exploiting the linear relationship between the temperature and voltage for the constant current in the temperature range of 275 K to 333 K. Within the precision of our experiment, the results obtained are in good agreement with the known value energy gap in silicon. The temperature dependence of Eg for silicon has also been studied.

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Advice for Student Authors How to Organize Your Research Article

https://doi.org/10.33697/ajur.2008.011

Author(s):

Editorial Staff

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

ABSTRACT:

General information about article organization is presented. Questions about equation placement, chart or graph usage, figure placement, and bibliographic style are answered. Information about how a paper is reviewed is discussed, and steps for submitting a research paper are outlined. 

https://doi.org/10.33697/ajur.2008.001

Visual Editorial: AJUR Authors 2002 – 2008

https://doi.org/10.33697/ajur.2008.002

Author(s):

C. C. Chancey

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

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Design and Evaluation of a Syringe Pump for Determining the Critical Micelle Concentration of Surfactants by Making Use of the Drop Volume Method

https://doi.org/10.33697/ajur.2008.003

Author(s):

Jacob Friest, Benjamin Dowse, Dru Delaet

Affiliation:

Department of Physical Science, Southern Utah University, Cedar City, Utah 84720 USA

ABSTRACT:

Surfactants are of widespread importance in biochemistry, the detergent industry, analytical chemistry, and many other areas that are both academically and industrially important. Here we report the design and evaluation of an inexpensive and novel syringe pump. The system is suitable for the academic and small laboratory setting. It has been tested here by measuring the Critical Micelle Concentration (CMC) of surfactants with a relatively high degree of accuracy. The system may also be adapted for use in chromatography, controlled reagent dispensing for synthesis or other biochemical and biomedical applications.

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Some Results on the Variation of Composite Function of Functions of Bounded d Variation

https://doi.org/10.33697/ajur.2008.004

Author(s):

Mohsen Soltanifar

Affiliation:

Department of Mathematics, Faculty of Science, K.N. Toosi University of Technology, P.O. Box 16315-1618, Tehran IRAN

ABSTRACT:

In this paper we discuss conditions under which the composite function of two functions of bounded d variation is also of bounded d variation.

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Stairway to Self-Organized Criticality: SOC on a Slope using Relative Critical Heights

https://doi.org/10.33697/ajur.2008.005

Author(s):

Clinton Davis

Affiliation:

Department of Physics and Astronomy, Ohio Wesleyan University, Delaware, Ohio 43015 USA

ABSTRACT:

A computational model of loose snow avalanches was studied as an example of Self-Organized Criticality (SOC). The distribution of the magnitudes of avalanches was measured for a stair-stepped system with various critical relative differences and system slopes. Depending on the configuration, the model showed either power law behaviors or a Gaussian distribution. For configurations that displayed power laws, the slope of the power law was dependent on the configuration of the system. 

https://doi.org/10.33697/ajur.2007.016

Editorial: On the Cutting Edge — New Areas of Undergraduate Research

https://doi.org/10.33697/ajur.2007.017

Author(s):

C. C. Chancey

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

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Using Meiobenthic Species as a Measure of the Impact of Acid Mine Outflows on the Tioga River in North Central Pennsylvania

https://doi.org/10.33697/ajur.2007.018

Author(s):

Carissa Ganong and Gregory Carson, Department of Chemistry and Physics

John Kirby, Department of Biology

Affiliation:

Mansfield University, Mansfield, Pennsylvania 16933 USA

ABSTRACT:

In this study meiobenthic communities were sampled from several acid mine drainage (AMD) impacted sites along the Tioga River in North Central Pennsylvania. Concentrations of several chemical indicators of aquatic health (Fe+2/Fe+3, Mn+2, and SO4-2) were measured along with the pH. Meiobenthic communities were present at all AMD impacted locations but diversity and abundance varied. The diversity and abundance at the AMD impacted sites was inversely related to the concentration of several key acid mine drainage indicators. Macroinvertebrate species were collected only at the unimpacted head waters of the Tioga River. All other sampled locations were devoid of macroinvertebrate species.

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Studies of E. coli and Coliform Bacteria Contamination in Mussels (Geukensia demissa) Collected from Guion Creek and Its Correlation to Water Flow Rate

https://doi.org/10.33697/ajur.2007.019

Author(s):

Pretima G. Persad and Anna K. Yeung-Cheung

Affiliation:

Department of Biology, Manhattanville College, Purchase, New York 10577 USA

ABSTRACT:

Ribbed mussels (Geukensia demissa) were collected from a highly contaminated Guion Creek, Mamaroneck Harbor, NY and were compared with Harbor Island Park and Shore Acres Beach, for amounts of bacteria. Mussels were also collected from a pristine beach, Read Sanctuary, Rye. The water flow rate was measured at all sites. The results showed that the amount of E. coli and coliform bacteria recovered from mussels were significantly higher in Guion Creek and its water flow rate was significantly lower when compared to three other sites. On the contrary, the highest water flow rate and lowest amounts of bacteria were recovered from mussels collected at Read Sanctuary. A negative correlation of water flow rate with amounts of E. coli and coliform recovered from mussels at all sites was found. Results suggested that a slow water flow rate in Guion Creek might be one of the contributing factors to the high bacterial loads.

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Extraction, Identification, and Quantification of Harmala Alkaloids in Three Species of Passiflora

https://doi.org/10.33697/ajur.2007.020

Author(s):

Abigail Frye and Catherine Haustein

Affiliation:

Department of Chemistry, Central College, 812 University, Pella, Iowa 50219 USA

ABSTRACT:

Harmala alkaloids are a common plant extract with a number of reported uses including as stimulants and monoamine oxidase (MAO) inhibitors. Their reported activity has led some researchers to identify them as the principal active constituent in passion flowers, an abundant plant which has been identified to have a number of pharmaceutical uses of its own. Harmalas are commonly extracted using chloroform; however, in this case, a green extraction process using ethyl acetate and sodium bicarbonate was applied. Analysis of the harmala alkaloids in Passiflora caerulea, Passiflora incarnata and Passiflora “Coral Glow” was performed quantitatively using the HPLC. Comparison of HPLC results from plant extracts to results from standard solutions concluded that harmol and harmine were present in minor amounts in Passiflora incarnata, harmine was present in large amounts in Passiflora caerulea, and no significant amounts of harmala alkaloids were found in Passiflora “Coral Glow”. The extraction process and HPLC analysis also revealed the presence of the flavonoid derivative Vitexin in Passiflora incarnata. Vitexin was present in relatively large amounts, and as a flavonoid derivative, the compound may have powerful antioxidant activity.

https://doi.org/10.33697/ajur.2007.011

Guest Opinion: Undergraduate Research Assistants

https://doi.org/10.33697/ajur.2007.012

Author(s):

Barbara Hetrick

Affiliation:

Department of Biology, University of Northern Iowa, Cedar Falls, Iowa 50614-0421 USA

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Acoustic Imaging of Sound Sources with a Student-Designed Acoustic Camera

https://doi.org/10.33697/ajur.2007.013

Author(s):

Joachim Sigl and René Scheucher

Affiliation:

Department of Automotive Engineering, FH Joanneum University of Applied Sciences, Alte Poststr. 149, A-8020 Graz, AUSTRIA

ABSTRACT:

An acoustic camera consists of a microphone array, a data recorder and sound analysis- and -visualization software. It creates a color-coded sound map that displays the sound sources overlaid on the visual image of the recorded object. The sound maps are usually produced by analyzing the phase differences of the signals measured by the array microphones. Delay-and-sum beamformer and multiple signal classification (MUSIC) techniques are used in this work for the localization of sound sources. Beamformers are able to determine the amplitude of incident sound, but suffer from poor resolution and from ghost images. MUSIC, on the other hand, is an established technique for efficient and accurate noise source location, which can provide high-resolution source maps, but does not provide any information about the sound level. The combination of both methods gives comprehensive information about the acoustic emission of the system under investigation.

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Electrostriction Effects During Defibrillation

https://doi.org/10.33697/ajur.2007.014

Authors and Affiliations:

Michelle M. Fritz
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 USA

Phil W. Prior and Bradley J. Roth
Department of Physics, Oakland University, Rochester, Michigan 48309 USA

ABSTRACT:

Background—The electric field applied to the heart during defibrillation causes mechanical forces (electrostriction), and as a result the heart deforms. This paper analyses the physical origin of the deformation, and how significant it is. Methods—We represent the heart as an anisotropic cylinder. This simple geometry allows us to obtain analytical solutions for the potential, current density, charge, stress, and strain. Results—Charge induced on the heart surface in the presence of the electric field results in forces that deform the heart. In addition, the anisotropy of cardiac tissue creates a charge density throughout the tissue volume, leading to body forces. These two forces cause the tissue to deform in a complicated manner, with the anisotropy suppressing radial displacements in favor of tangential ones. Quantitatively, the deformation of the tissue is small, although it may be significant when using some imaging techniques that require the measurement of small displacements. Conclusions—The anisotropy of cardiac tissue produces qualitatively new mechanical behavior during a strong, defibrillation-strength electric shock.

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Analysis of the Ferromagnetic Transition in Melt-Spun Gadolinium Nanocrystals

https://doi.org/10.33697/ajur.2007.015

Authors and Affiliations:

J.G. Bohnet and P. M. Shand
Department of Physics, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

J. Goertzen and J.E. Shield
Department of Mechanical Engineering and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 USA

D. Schmitter, G. Shelburne and D. L. Leslie-Pelecky
Department of Physics & Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 USA

ABSTRACT:

Magnetic materials are present in rewriteable disk drives, electric motors and generators, and signal transformers/receivers. To improve the performance of these and other devices, much research in magnetism continues to be done. In particular, materials that are disordered on the atomic and nanometer scales have recently been the subject of extensive research, as the arrangement of atoms and the interactions between them significantly affect a material’s magnetic properties. We have prepared a disordered pure gadolinium (Gd) system using a melt-spinning technique. This resulted in a system of Gd crystals on the order of 160 nm in size embedded in an amorphous Gd matrix. The structure was identified using X-ray analysis and transmission electron microscopy. AC susceptibility and DC magnetization measurements at various temperatures (280 -350 K) and DC bias fields (0 – 3 kOe) were performed on a sample of the nanocrystalline Gd. Using modified Arrott-Noakes plots and scaling ideas for a second-order phase transition, critical exponents and the Curie temperature (TC) for the ferromagnetic transition in the nanocrystalline Gd system were obtained. TC was found to be 289.70 K, and the critical exponents had shift away from those of bulk Gd and toward those of the Heisenberg model with short-range interactions, indicating that melt-spinning suppressed the interactions present in bulk Gd. 

https://doi.org/10.33697/ajur.2007.006

Guest Opinion: Undergraduate Research at the University of Northern Iowa

https://doi.org/10.33697/ajur.2007.007

Author(s):

Joel K. Haack

Affiliation:

College of Natural Sciences, University of Northern Iowa, Cedar Falls, Iowa 50614-0181 USA

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Identification, Optimization and Preliminary X-ray Diffraction of a New Crystal Form of the
N-terminal Domain of the HIV-1 CA Protein

https://doi.org/10.33697/ajur.2007.008

Author(s):

Ryan Van Woerkom, Andrew Dixon, Rob Oslund and Bruce R. Howard

Affiliation:

Department of Physical Science, Southern Utah University, Cedar City, Utah 84720 USA

ABSTRACT:

In an effort to better understand the detailed intersubunit interactions of the N-terminal Domain of the CA (capsid) protein from HIV-1 within the conical core of the mature virus, we have identified a novel crystal form of this domain and have optimized conditions to grow single protein crystals suitable for x-ray analysis. These high quality crystals diffract to better than 1.8 Å resolution on a rotating anode generator.

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Particle Beam Waist Location in Plasma Wakefield Acceleration: Methods, Data and Discussion

https://doi.org/10.33697/ajur.2007.009

Author(s):

Adrian Down

Affiliation:

Department of Physics, University of California, Berkeley, California 94720-7300 USA

ABSTRACT:

The role of beam waist location in interactions between a plasma and a particle beam is not yet fully understood. Nonlinear effects with the plasma make an analysis of such interactions difficult. Five simulations are presented in this report, with the waist location of a beam of ultra-relativistic electrons propagating through one meter of self-ionized lithium plasma. The simulation parameters are chosen to model the recent experiment 167 at the Stanford Linear Accelerator, relevant to the design of future plasma wakefield accelerating afterburners. It is found that beams focused near the point of entry into the plasma propagate further into the plasma and accelerate witness particles to a greater maximum energy before disintegrating. These results could indicate that ion channel formation is dependent on the drive beam waist location and that the plasma accelerating medium can have an observable effect on the focusing of the drive beam.

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Molecular Dynamics Simulations of Hexane Deposited onto Graphite: An Explicit–Hydrogen Model at ρ = 1 

https://doi.org/10.33697/ajur.2007.010

Authors and Affiliations:

M.J. Connolly and M.W. Roth
Department of Physics, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

Carlos Wexler
Department of Physics and Astronomy, University of Missouri – Columbia, Columbia, Missouri 65211 USA

Paul A. Gray
Department of Computer Science, University of Northern Iowa, Cedar Falls, Iowa 50614-0507 USA

ABSTRACT:

We present the results of parallel Molecular Dynamics computer simulations of hexane (C6H14) adlayers physisorbed onto a graphite substrate in the density range 0.5 ≤ ρ ≤1 in units of monolayers, with emphasis on monolayer completion (ρ = 1). The hexane molecules are modeled to explicitly include hydrogens and the graphite is modeled as a six – layer all atom structure. In the explicit hydrogen simulations, the herringbone solid loses its orientational order at T1 = 140 °K, fairly consistent with results of UA simulations. However there is almost no nematic meso-phase or negative energy change at the loss of herringbone order. The explicit hydrogen melting temperature is T2 = 160 °K—somewhat lower than seen in experiment and in UA simulations. Generally, results for the all–atom model agree well with experiment, as the molecules remain overall flat on the substrate in the solid phase. At densities below about ρ = 0.875 the system supports a connected network which stabilizes it against thermal fluctuations and yields much more reasonable sub-monolayer- melting behavior. The united atom picture, on the other hand, departs significantly from experiment at most sub-monolayer- densities and gives melting temperatures several decades below what is experimentally observed. The purpose of this work is to compare the results of UA and explicit hydrogen MD simulations of hexane on graphite mainly at ρ = 1, to discuss cursory explorations at sub-monolayer- densities and mention open questions related to the system that are worth pursuing. Various structural and thermodynamic order parameters and distributions are presented in order to outline such differences. 

https://doi.org/10.33697/ajur.2007.001

Raison d’etre: American Journal of Undergraduate Research

https://doi.org/10.33697/ajur.2007.002

Author(s):

C. C. Chancey

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614-0150 USA

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Particle Beam Waist Location in Plasma Wakefield Acceleration: Introduction and Background

https://doi.org/10.33697/ajur.2007.003

Author(s):

Adrian Down

Affiliation:

Department of Physics, University of California, Berkeley, California 94720-7300 USA

ABSTRACT:

The role of beam waist location in interactions between a plasma and a particle beam is not yet fully understood. Nonlinear effects with the plasma make an analysis of such interactions difficult. Five simulations are presented in this report, with the waist location of a beam of ultra-relativistic electrons propagating through one meter of self-ionized lithium plasma. The simulation parameters are chosen to model the recent experiment 167 at the Stanford Linear Accelerator, relevant to the design of future plasma wakefield accelerating afterburners. It is found that beams focused near the point of entry into the plasma propagate further into the plasma and accelerate witness particles to a greater maximum energy before disintegrating. These results could indicate that ion channel formation is dependent on the drive beam waist location and that the plasma accelerating medium can have an observable effect on the focusing of the drive beam.

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Impaired Spatial Learning and Reduced MK-801 Associated Behavioral Deficits in Rodents Following Early Postnatal Exposure to Low-level Lead

https://doi.org/10.33697/ajur.2007.004

Author(s):

Jing Guo

Affiliation:

Department of Life Sciences, University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4 CANADA

ABSTRACT:

The current research aimed to investigate the effects of early postnatal exposure to low-level lead on the spatial learning of Long-Evans Hooded rats tested in the Morris water maze. To explore possible neurotoxic actions of lead on the N-methyl-D-aspartate (NMDA) receptors, the non-competitive NMDA receptor antagonist (+)-5-methyl-10,11-dihydroxy-5h- dibenzo(a,d)cyclohepten-5,10-imine (MK-801) was used. Two-day-old pups were randomly assigned to 0.1% lead carbonate diet or control diet and weaned onto regular food on postnatal day (PND) 23. Spatial acquisition was assessed from PND 24 to PND 27. Thirty minutes prior to behavioral testing, rats received an intraperitoneal (i.p.) injection of 0.1% MK-801 or saline. In the saline treatment group, Pb-exposed rats exhibited significantly longer overall mean escape latencies than those on the control diet, replicating the impaired spatial learning of Pb-exposed animals tested at a young age. Although MK-801 injection severely impaired animals’ water maze performance regardless of diet, it affected the performance of Pb-exposed animals to a lesser extent than animals on the control diet. No main effects of diet and drug were found for probe trials on PND 28 and PND 36, but interestingly, lead diet/MK-801 animals performed significantly better than control diet/MK-801 animals during the first probe trial. Unfortunately, MK-801 not only caused animals to display higher activity levels in the activity box, but also significantly impaired animals’ performance in the cued trial, suggesting non-specific sensorimotor deficits induced by MK-801 treatment might be responsible for animals’ poor performance. However, a significant drug by diet interaction in the escape latencies and the significantly better probe trial performance of Pb-exposed animals within the MK-801 treatment group imply that lead exposure actually alleviated behavioral deficits induced by MK-801 injection, providing evidence for a possible interaction between lead and MK-801 at the molecular level.

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Electrochemical Behavior of Hexacyano Iron (III/II) in Frozen Aqueous Electrolytes

https://doi.org/10.33697/ajur.2007.005

Author(s):

Leslie S. Books, Cherie Harris, and Kasem K. Kasem

Affiliation:

Department of Natural, Information and Mathematical Sciences, Indiana University Kokomo, Kokomo, Indiana 46904-9003 USA

ABSTRACT:

Electrochemical studies in phases that have been solidified by freezing were carried out. A 5 mM [Fe(CN)6]-3/-4 [Hexacyano Iron(III/II)] in either aqueous 0.1M KCl or in Agar gel containing 0.1 M KCl Agar were the two phase systems subject to this study. Formation of pristine ice crystals (salt free) in pure aqueous electrolyte explains smaller ΔEp recorded in frozen agar than that in absence of Agar. Furthermore, greater capacitive current was observed in frozen agar compared to that in frozen aqueous electrolyte. The results also indicates that while a liquid-like layer (≈ 4 time the value of √2Dt) is formed in frozen aqueous electrolyte at electrode/ electrolyte interface, opposite observation were recorded in frozen agar electrolyte. This evident from the thin-layer electrochemical outcome generated in frozen electrolyte, and low diffusion coefficient determined under these conditions. Deviations from the liquid state behavior at room temperature were explained on the assumption that freezing created conditions similar to those caused by application of high pressure on liquid electrochemical systems. Some kinetic data related to these systems were determined and recorded.

https://doi.org/10.33697/ajur.2006.017

Editorial Graphic: Our Authors by Location since June 2002

https://doi.org/10.33697/ajur.2006.018

Author(s):

C. C. Chancey

Affiliation:

American Journal of Undergraduate Research, University of Northern Iowa, Cedar Falls, Iowa 50614 USA

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Synthesis and Surfactant Studies of Dialkyl Dimethyl Quaternary Ammonium Bromide Formulations

https://doi.org/10.33697/ajur.2006.019

Author(s):

Rocky Barney, Tony Stark, and Dru Delaet

Affiliation:

Department of Physical Science, Southern Utah University, Cedar City, Utah 84720 USA

ABSTRACT:

Quaternary ammonium salts (otherwise known as quats) are commonly used active ingredients in biocide formulations used in the anti-microbial industry. Although quats have been established to be effective biocides, there are few studies investigating the maximization of biocidal efficacy in multiple component formulations using various carbon chain lengths. Reported here is the synthesis based on the Sn2 reaction of tertiary amines with alkyl bromide. Surfactant studies of the single and dual component systems were conducted, and the evaluation is explored.

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Using Fly Ash for Removal of Hazardous Substances in Water: An Undergraduate Environmental Chemistry Research Project

https://doi.org/10.33697/ajur.2006.020

Author(s):

Brianna Lambes and Shahrokh Ghaffari

Affiliation:

Ohio University-Zanesville, Zanesville, OH 43701

ABSTRACT:

Fly ash obtained from a coal burning power plant was used to separate dissolved component of unleaded fuel from water using column chromatography. The results of this study indicate complete removal of the unleaded fuel from water. Eluted water collected from fly ash packed column has no odor. A successful field test at a larger scale shows the real environmental benefit of using this approach for removal of environmentally hazardous materials.

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A Characterization of Refinable Rational Functions

https://doi.org/10.33697/ajur.2006.021

Authors and Affiliations:

Paul Gustafson
Department of Mathematics, Texas A&M University, College Station, Texas 77843-3368 USA

Nathan Savir
Department of Mathematics, Princeton University, Princeton New Jersey 08544-1000 USA

Ely Spears
Department of Mathematics, Rose-Hulman Institute of Technology, 5000 Wabash Avenue, Terre Haute, Indiana 47803 USA

ABSTRACT:

In recent decades, refinable functions have become increasingly popular due to their desirable properties in many applications. Rational functions, however, are not as well-behaved as some other classes of functions and have seemingly escaped notice in terms of refinability. The authors spent the summer of 2006 investigating the refinability of rational functions while attending a National Science Foundation funded Research Experience for Undergraduates program at Texas A & M University. Preliminary simplifications to the general case are presented in a chronological collection of lemmas. A complete characterization of refinable rational functions follows with an interesting connection to an open problem in number theory.

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Phosphorus Sorption by Sediments from Wetlands in the Cedar River Watershed

https://doi.org/10.33697/ajur.2006.022

Author(s):

Ann Schwemm, Renee Pasker, Maureen Clayton and Ed Brown

Affiliation:

Environmental Programs, University of Northern Iowa, Cedar Falls, Iowa 50614-0506 USA

ABSTRACT:

Excess phosphorus can lead to eutrophication of aquatic ecosystems, which can indirectly cause many species to suffer due to lower oxygen levels. The intent of this project was to determine if wetlands draining agricultural soil in the Cedar River watershed are removing phosphorus prior to empting into a tributary of the Cedar River. To determine the fate and transport of phosphorus in the wetlands, the total phosphorus (TP) of both the water and sediments was measured, and the ability for sediments to remove phosphate was also determined. The TP in the water column in the wetlands varied temporally from 700 to 1700 μg/L. Dissolved inorganic phosphate (SRP) totals were usually less than 10% of the total P, with a modest spike observed after a rainfall event. The low levels of SRP in the water led to testing of the TP levels in sediments and TP sorption capabilities. The TP of the sediment varied spatially from 500-700 μg/gdw. Sediments from the tributary (Beaver Creek) had total phosphorus levels of about 500 μg/gdw and the inlet to the wetlands varied from 300-400 μg/gdw. Depending on sampling locations, maximum sorption for sediments from the main body of the wetland ranged from 2-9 mg/gdw. Sediments from both the tributary (Beaver Creek) and the inlet to the wetlands sorbed about 7 mg/gdw. The results suggest that sediments in the wetlands are not yet saturated with phosphorus and therefore, when aerobic, can prevent phosphorus transport to rivers and streams.