Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

2022

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 631 - 660 of 1634

Full-Text Articles in Chemistry

An Economical Source For Peroxidase: Maize Cobs, Hathama Razooki Hasan, Ali Waleed Al- Ani May 2022

An Economical Source For Peroxidase: Maize Cobs, Hathama Razooki Hasan, Ali Waleed Al- Ani

Karbala International Journal of Modern Science

According to the current situation of peroxidase (POD), the relevant studies on this enzyme indicated its importance as a tool in clinical biochemistry and different industrial fields. Most of these studies used the fruits and vegetables as source of this enzyme. So that in order to couple the growing requirements for POD with the recent demands for reduc-ing disposal volume by recycling the plant waste, the aim of the present study was to extract POD through management of municipal bio-waste of Iraqi maize species. A simple, green and economical method was used to extract this enzyme. Our results revealed that …

Go to article

Efficient Removal Of Common Organic Pollutants From Water By Zn-Doped Tio2 Nanoparticles With Different Applications, Khaled Elgendy, Ibrahim Elmehasseb, Saleh Kandil May 2022

Efficient Removal Of Common Organic Pollutants From Water By Zn-Doped Tio2 Nanoparticles With Different Applications, Khaled Elgendy, Ibrahim Elmehasseb, Saleh Kandil

Karbala International Journal of Modern Science

Water purification via adsorption without energy consumption was considered a green process. Zn-doped TiO2 nanoparticles were fabricated by the Sol-gel method and characterized by different analysis techniques. Zinc doping of TiO2 increases the surface area to 26.7m2g-1 with adsorption results, 75.1%, 71.1%, and 68.2% for methylene blue, ofloxacin, and SLS, respectively. Variable affecting factors on adsorption have been studied. The adsorption behavior fitted with Langmuir and Freundlich equations than Temkin isotherm, indicating the preferred heterogeneous adsorption at equivalent adsorbent sites. The application of nanoparticles in many synthetic specimens of pollutants gave excellent removal results, which exceeded 75% of detoxification.

Go to article

Synthesis Of Cuo/Zno And Mgo/Zno Core/Shell Nanoparticles With Plasma Jets And Study Of Their Structural And Optical Properties, Raghad S. Mohammed, Kadhim A. Aadim, Khalid A. Ahmed May 2022

Synthesis Of Cuo/Zno And Mgo/Zno Core/Shell Nanoparticles With Plasma Jets And Study Of Their Structural And Optical Properties, Raghad S. Mohammed, Kadhim A. Aadim, Khalid A. Ahmed

Karbala International Journal of Modern Science

This paper reports the synthesis of CuO/ZnO and MgO/ZnO core/shell nanoparticles using atmospheric plasma jets. The characterization of the synthesized CuO/ZnO and MgO/ZnO core/shell nanoparticles were confirmed by a series of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and UV–Vis spectroscopy. The XRD analysis confirmed no other peaks related to the secondary phases for CuO, MgO, or ZnO, indicating the purity of these nanoparticles. Additionally, EDX analysis confirmed the formation of high purity CuO/ZnO and MgO/ZnO core/shell nanoparticles. The surface morphology, which represented the high agglomeration rate, was investigated using …

Go to article

Numerical Analysis Of A Silicon-Based Electro-Optic Modulator, Mario Alberto García-Ramírez, Orfil González-Reynoso, Everardo Vargas-Rodríguez, Miguel Angel Bello-Jiménez, Abel García-Barrientos May 2022

Numerical Analysis Of A Silicon-Based Electro-Optic Modulator, Mario Alberto García-Ramírez, Orfil González-Reynoso, Everardo Vargas-Rodríguez, Miguel Angel Bello-Jiménez, Abel García-Barrientos

Karbala International Journal of Modern Science

A phase shift electro-optic semiconductor structure that features a Mach-Zehnder Interferometer (MZI) is numerically analyzed. The interferometer structure considers a highly-doped Si-based waveguide that can control the phase shift by varying the refractive index through the carrier concentration while applying a control voltage. To analyze the structure, Kramers-Kronig dispersion relations, the effective index method and the Drude model are implemented within a finite element software. As a result, for an optical waveguide structure with a 9 mm length and 10 V, it is possible to obtain a phase shift by that allows, at the output of the MZI, total interference …

Go to article

Partial Pseudo-Random Hashing For Transactional Memory Read/Write Data Processing And Validation, G M Sridevi, Ashoka D V, B V Ajay Prakash May 2022

Partial Pseudo-Random Hashing For Transactional Memory Read/Write Data Processing And Validation, G M Sridevi, Ashoka D V, B V Ajay Prakash

Karbala International Journal of Modern Science

Development of a bypass parallel processing block is one of the emerging and interesting research areas in memory read/write application domain. Many Random Number Generation (RNG) techniques have been introduced for processing the data in storage memory. But the limitations include reduced efficiency, increased computational complexity, high area consumption and higher cost. This paper presents a novel dynamic memory register with optimal XOR design based on partial pseudo-random hashing to process transactional memory read/write data. Transfer characteristics of the current are analysed based on the pseudo differential pair for proficient memory utilization. A memory window is then created and adjusted …

Go to article

A Content-Based File Identification Dataset: Collection, Construction, And Evaluation, Saja Dheyaa Khudhur, Hassan Awheed Jeiad May 2022

A Content-Based File Identification Dataset: Collection, Construction, And Evaluation, Saja Dheyaa Khudhur, Hassan Awheed Jeiad

Karbala International Journal of Modern Science

File-Type Identification (FTI) is one of the essential functions that can be performed by examining the data blocks' magic numbers. However, this examination leads to a challenge when a file is corrupt, or these magic numbers are missing. Content-based analytics is the best way for file type identification when the magic numbers are not available. This paper prepares and presents a content-based dataset for eight common types of files based on twelve features. We designed our dataset to be used for supervised and unsupervised machine learning models. It provides the ability to classify and cluster these types into two levels, …

Go to article

Nigella Sativa Methanol Extract Inhibits Pc-3 Cell Line Colonization, Induced Apoptosis, And Modulated Lc3-Based Autophagy, Yusuf Toy, Merve Kivrik, Marwa H. Alkhafaji, Aryan M. Faraj, Ibrahim H. Gecibesler, Can A. Ağca May 2022

Nigella Sativa Methanol Extract Inhibits Pc-3 Cell Line Colonization, Induced Apoptosis, And Modulated Lc3-Based Autophagy, Yusuf Toy, Merve Kivrik, Marwa H. Alkhafaji, Aryan M. Faraj, Ibrahim H. Gecibesler, Can A. Ağca

Karbala International Journal of Modern Science

Nigella sativa has various pharmacological properties and has been used throughout history for a variety of reasons. However, there is limited data about the effects of Nigella sativa (NS) on human cancer cells. This study aimed at observing the roles of methanolic extract of N. sativa on apoptosis and autophagy pathway in the Human PC3 (prostate cancer) cell line. The cell viability was checked by MTT assay. Clonogenic assay was performed to demonstrate clonogenicity and Western blot was used to check caspase-3, TIGAR, p53, and LC3 protein expression. The results demonstrated that PC3 cell proliferation was inhibited, caspase-3 and p53 …

Go to article

Ultrasound-Assisted Dibutyl Phthalate Nanocapsules Preparation And Its Application As Corrosion Inhibition Coatings, Uday Bagale, Ammar Kadi, Irina Potoroko, Vinay Rangari, Minakshi Mahale May 2022

Ultrasound-Assisted Dibutyl Phthalate Nanocapsules Preparation And Its Application As Corrosion Inhibition Coatings, Uday Bagale, Ammar Kadi, Irina Potoroko, Vinay Rangari, Minakshi Mahale

Karbala International Journal of Modern Science

The current research employs an encapsulation of dibutyl phthalate (DBP) as a corrosion inhibitor in situ polymerization using a sonochemical method to form nanocapsules. The prepared nanocapsules were characterization by using Malvern particle size, Fouri-er transforms infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and Transmission electron microscope (TEM), and thermal and mechanical test to check particle size, morphology, and stability of nanocapsules. Later prepared DBP nanocapsules were incorporated in standard epoxy coating to check its corrosion inhibition resistance. The results show that nanocapsules are spherical, with an average particle size of 337 nm. Scratch nanocapsules epoxy coating shows improves coating …

Go to article

Heterogeneous Catalytic Degradation Of Dye By Fenton-Like Oxidation Over A Continuous System Based On Box–Behnken Design And Traditional Batch Experiments, Imad M. Luaibi, Mohammed A. Atiya, Ahmed K. Hassan, Zainab A. Mahmoud May 2022

Heterogeneous Catalytic Degradation Of Dye By Fenton-Like Oxidation Over A Continuous System Based On Box–Behnken Design And Traditional Batch Experiments, Imad M. Luaibi, Mohammed A. Atiya, Ahmed K. Hassan, Zainab A. Mahmoud

Karbala International Journal of Modern Science

In this study, iron was coupled with copper to form a bimetallic compound through a biosynthetic method, which was then used as a catalyst in the Fenton-like processes for removing direct Blue 15 dye (DB15) from aqueous solution. Characterization techniques were applied on the resultant nanoparticles such as SEM, BET, EDAX, FT-IR, XRD, and zeta potential. Specifically, the rounded and shaped as spherical nanoparticles were found for green synthesized iron/copper nanoparticles (G-Fe/Cu NPs) with the size ranging from 32-59 nm, and the surface area was 4.452 m2/g. The effect of different experimental factors was studied in both batch and continuous …

Go to article

Optical Measurement And Performance Prediction Of Solar Pv System In Al-Khidhir Zone/Iraq, Faten Sh. Zainulabdeen, Jaber O. Dahloos, Ahmed F. Atwan, Naseer K. Kasim May 2022

Optical Measurement And Performance Prediction Of Solar Pv System In Al-Khidhir Zone/Iraq, Faten Sh. Zainulabdeen, Jaber O. Dahloos, Ahmed F. Atwan, Naseer K. Kasim

Karbala International Journal of Modern Science

People have tended for investing the sources of renewable energy, especially solar energy, as they are clean and environmentally friendly sources. The present work aims to invest the measured data of solar irradiance, maximum ambient temperatures and wind speed provided by Al Khidhir Meteorological Station to predict the minimum performance of photovoltaic solar systems (NT-R0E3E-SHARP) for electric power generation. The single diode model is used to calculate the minimum output power produced by solar module and its minimum conversion efficiency based on soalr irradiance, maximum ambient temperatures and wind speed throughout 2020. The results indicate that the annual solar irradiance …

Go to article

Probing Convergence In Orthogonal Conjugated Catalysis By T4 Lysozyme Utilizing Biophysical Characterization, William Turner May 2022

Probing Convergence In Orthogonal Conjugated Catalysis By T4 Lysozyme Utilizing Biophysical Characterization, William Turner

Master of Science in Chemical Sciences Theses

Conjugated polymers have become highly attractive as they afford unique material properties that make them promising for a wide range of applications, such as photovoltaics and drug delivery systems. However, these conjugated polymers require extensive synthetic steps involving hazardous organic solvents or metal-based catalysts yielding toxic waste streams. To remedy this, enzymes have emerged as a highly valuable alternative to synthesizing these polymers as they are able to be produced in environmentally benign conditions and have played a pivotal role in various biosynthetic strategies in recent years. Serving as model systems, lysozymes have been shown to polymerize 2-ethynylpyridine (2-EP) via …

Go to article

Determining The Structure And Activity Of A Pseudomonas Aeruginosa Protein, Ivyp2, Katherine Letsinger May 2022

Determining The Structure And Activity Of A Pseudomonas Aeruginosa Protein, Ivyp2, Katherine Letsinger

Master of Science in Chemical Sciences Theses

Various biophysical methods were employed to structurally characterize and assess the activity of an important resistance factor (Ivyp2) from the multi-drug resistant Gram-negative bacterium Pseudomonas aeruginosa. This opportunistic pathogen accounts for approximately 10% of all hospital-acquired infections in the United States and contains a number of virulence factors that aid in its ability to infect and colonize immunocompromised individuals and those with cystic fibrosis. One of these factors – inhibitor of vertebrate lysozyme, or Ivy – neutralizes the lytic activity of lysozyme, an antimicrobial enzyme part of the innate immune system that hydrolyzes the linkages between bacterial cell wall subunits. …

Go to article

Simple Arenes As Aryne Synthetic Equivalents Via Sulfonium Salt Intermediates, Riley A. Roberts May 2022

Simple Arenes As Aryne Synthetic Equivalents Via Sulfonium Salt Intermediates, Riley A. Roberts

Student Research Symposium

Arynes are ephemeral molecules that are yet to be fully exploited in synthetic strategy because they are often challenging to access. These reactive intermediates participate in a myriad of reactions that conventional chemistry is incapable of, making them extremely useful for the synthesis of important molecules like pharmaceuticals and agrochemicals. While classical approaches for synthesizing arynes employ cheap starting material, extremely harsh reagents are necessary to generate the aryne. In contrast, methods that do not require harsh reaction conditions do require starting material that is exceedingly difficult to synthesize. To access arynes quickly and efficiently, the work described herein aims …

Go to article

Comparison Of Heavy Metals In Spinach Grown On The Roof Ground Location At Portland State University, Tyler A. Robin May 2022

Comparison Of Heavy Metals In Spinach Grown On The Roof Ground Location At Portland State University, Tyler A. Robin

Student Research Symposium

As a result of urbanization, fresh, healthy food can be expensive and easily contaminated but space for local farming is limited. Roofs can be underutilized in densely populated cities and can offer a space for local fresh farming. The purpose of this study is to continue a previous study done in 2021, to find if growing leafy vegetables on the roof can limit heavy metal exposure from air pollutants. This study compares spinach grown on the roof in 2021, 2019 and spinach bought from stores around the Portland State University campus and the heavy metals found in these greens. The …

Go to article

Computational Investigation Of The Mechanism Of An Octahedral Ni(Ii) Proton Reduction Catalyst And Importance Of Intramolecular Hydrogen Bonding, Avik Bhattacharjee, Dayalis S.V. Brown, Carolyn N. Virca, Trent E. Ethridge, Oreana Mendez Galue, Uyen T. Pham, Theresa M. Mccormick May 2022

Computational Investigation Of The Mechanism Of An Octahedral Ni(Ii) Proton Reduction Catalyst And Importance Of Intramolecular Hydrogen Bonding, Avik Bhattacharjee, Dayalis S.V. Brown, Carolyn N. Virca, Trent E. Ethridge, Oreana Mendez Galue, Uyen T. Pham, Theresa M. Mccormick

Student Research Symposium

Water-splitting to make hydrogen gas is of extreme importance in the field of alternative energy research. Transition-metal complexes are capable of catalyzing the conversion of water to hydrogen at higher pH, with low overpotential. Our research focuses on the importance of intramolecular hydrogen bonding (H-bonding) on the pKa and thermodynamic stability of the catalytic intermediates of a well-known proton-reduction catalyst, nickel (II) tris-pyridinethiolate. Density Functional Theory (DFT) calculations on the parent catalyst and eleven derivatives demonstrate geometric isomer formation after the protonation step of catalysis. These isomers differ in the relative thermodynamic stabilities and pKa values, which can be attributed …

Go to article

Stabilization Of Phenanthrene Anions In Helium Nanodroplets, Siegfried Kollotzek, Farhad Izadi, Miriam Meyer, Stefan Bergmeister, Fabio Zappa, Stephan Denifl, Olof E. Echt, Paul Scheier, Elisabeth Gruber May 2022

Stabilization Of Phenanthrene Anions In Helium Nanodroplets, Siegfried Kollotzek, Farhad Izadi, Miriam Meyer, Stefan Bergmeister, Fabio Zappa, Stephan Denifl, Olof E. Echt, Paul Scheier, Elisabeth Gruber

Faculty Publications

It has been debated for years if the polycyclic aromatic hydrocarbon phenanthrene exists in its anionic form, or, in other words, if its electron affinity (EA) is positive or negative. In this contribution we confirm that the bare phenanthrene anion Ph- created in a binary collision with an electron at room temperature has a lifetime shorter than microseconds. However, the embedding of neutral phenanthrene molecules in negatively charged helium nanodroplets enables the formation of phenanthrene anions by charge transfer processes and the stabilization of the latter in the ultracold environment. Gentle shrinking of the helium matrix of phenanthrene-doped HNDs …

Go to article

Unusual High-Frequency Mechanical Properties Of Polymer-Grafted Nanoparticle Melts, Mayank Jhalaria, Yu Chang, Yucheng Huang, Brian C. Benicewicz, Sanat K. Kumar, George Fytas May 2022

Unusual High-Frequency Mechanical Properties Of Polymer-Grafted Nanoparticle Melts, Mayank Jhalaria, Yu Chang, Yucheng Huang, Brian C. Benicewicz, Sanat K. Kumar, George Fytas

Faculty Publications

Brillouin light spectroscopy is used to measure the elastic moduli of spherical polymer-grafted nanoparticle (GNP) melts as a function of chain length at fixed grafting density (0.47  chains/nm2) and nanoparticle radius (8 nm). While the moduli follow a rule of mixtures (Wood’s law) for long chains, they display enhanced elasticity and anomalous dissipation for graft chains <1⁢0⁢0  kDa. GNP melts with long polymers at high 𝜎 have a dry zone near the GNP core, surrounded by a region where the grafts can interpenetrate with chain fragments from adjacent GNPs. We propose that the departures from Wood’s law for short chains are due to the effectively larger silica volume fraction in the region where sound propagates—this is caused by the short, interpenetrated chain fragments being pushed out of the way. We thus conclude that transport mechanisms (of gas, ions, sound, thermal phonons) in GNP melts are radically different if interpenetrated chain segments can be “pushed out of the way” or not. This provides a facile new means for manipulating the properties of these materials.

Go to article

Computational And Spectroscopic Studies Of New Sulfur-Containing Dipole-Bound Anions, Nicholas Allen Kruse May 2022

Computational And Spectroscopic Studies Of New Sulfur-Containing Dipole-Bound Anions, Nicholas Allen Kruse

Honors Theses

Sulfur and Nitrogen are essential ingredients in both life-supporting and light-harvesting molecules. Their presence also usually leads to the delocalization of electrons and large dipole and quadrupole moments. Such molecules are sometimes able to form negative ions through the electrostatic binding of an excess electron. These so-called multipole-bound (dipole-bound, quadrupole-bound, etc.) anions have been shown to be important in radiation damage in biology and electron transport processes. Here, we present our recent computational and experimental results studying the creation of new multipole-bound anions.

Go to article

The Design Of A Pcr-Based Assay To Detect And Isolate The Serine Palmitolytransferase Gene From Environmental Bacteria, Lana Taylor May 2022

The Design Of A Pcr-Based Assay To Detect And Isolate The Serine Palmitolytransferase Gene From Environmental Bacteria, Lana Taylor

Honors Theses

Sphingolipids are a natural class of lipids that function as structural elements of cell membranes and signaling molecules for important cellular activities such as cell growth, differentiation, apoptosis, recognition, and adhesion. These lipids can be found universally in eukaryotic cells as well as some species of bacteria, such as those found in the human gut microbiome and in the environment in soils. Though sphingolipid production is rare in bacteria, both eukaryotic and prokaryotic sphingolipid biosynthesis begin with the condensation of serine and palmitoyl CoA into 3-ketodihydrosphingosine catalyzed by the enzyme serine palmitoyltransferase (SPT). In recent years, several studies have shown …

Go to article

Covalent Modification Of Recombinant Protein With Reactive Thiols, Sawyer Dulaney, Bailey Taylor May 2022

Covalent Modification Of Recombinant Protein With Reactive Thiols, Sawyer Dulaney, Bailey Taylor

Honors Theses

Many diseases cause chronic and painful inflammation in different body systems. One of the front-line drug classes to treat such inflammation is Nonsteroidal Anti-Inflammatory Drugs (NSAIDs). Despite the benefits of oral administration of NSAIDs, there are drawbacks to their long-term usage because they can cause detrimental effects on off-target systems in the body such as the liver, kidney, or the lining of the intestinal tract. An alternative to NSAIDs is the usage of hydrogels for targeted drug delivery. Hydrogels can provide drug delivery in a specific portion of the site of inflammation, thus allowing higher doses of medication to be …

Go to article

Development Of An Analytical Method For Determination Of Lead And Cadmium In Biological Materials By Gfaas Using Escherichia Coli As Model Substance, Michelle Catherine Gende, Martina Schmeling May 2022

Development Of An Analytical Method For Determination Of Lead And Cadmium In Biological Materials By Gfaas Using Escherichia Coli As Model Substance, Michelle Catherine Gende, Martina Schmeling

Chemistry: Faculty Publications and Other Works

In this work, an analytical method was developed for the determination of lead and cadmium in biological samples using graphite furnace atomic absorption spectrometry. Escherichia coli (E. coli) was chosen as model substance for this purpose as it is readily available in most laboratories and can be quickly and easily prepared with a high turnaround rate. Four different sample preparation methods were initially evaluated with respect to percent recovery, limit of detection, and limit of quantification, and the most promising one was developed further. The final process involving microwave assisted digestion of the sample with nitric acid …

Go to article

Aloso: Spectroscopy And Structure Of A New Group Of Astrochemical Molecules, Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco May 2022

Aloso: Spectroscopy And Structure Of A New Group Of Astrochemical Molecules, Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

No abstract provided.

Go to article

High Performance Liquid Chromatography Monitoring Reaction Kinetics, Ken Overway, Mary Ruth Shifflett May 2022

High Performance Liquid Chromatography Monitoring Reaction Kinetics, Ken Overway, Mary Ruth Shifflett

Chemistry Faculty Scholarship

To develop a chromatographic method to characterize enantioselective kinetics, the reaction between aromatic aldehydes and ephedrine will be monitored with High Performance Liquid Chromatography (HPLC). First, develop kinetics analysis procedure with the HPLC, the decomposition of aspartame was observed with citrate and phosphate buffers. The procedure produced an activation energy in the presence of phosphate buffer of 71.9 kJ/mol with a -0.126 % error. The aromatic aldehyde, benzaldehyde, and ephedrine were run through a stereospecific column to separate peaks with various mobile phases. A more nonpolar mobile phase is required for better peak and retention time separation.

Go to article

Drug Loaded Mesoporous Nanocarriers For The Detection Of Aspergillosis, Madeline Jewel Brooks May 2022

Drug Loaded Mesoporous Nanocarriers For The Detection Of Aspergillosis, Madeline Jewel Brooks

Honors Capstone Projects and Theses

No abstract provided.

Go to article

Spectral Signatures Of Hydrogen Thioperoxide (Hosh) And Hydrogen Persulfide (Hssh): Possible Molecular Sulfur Sinks In The Dense Ism, Charles Z. Palmer, Ryan C. Fortenberry, Joseph S. Francisco May 2022

Spectral Signatures Of Hydrogen Thioperoxide (Hosh) And Hydrogen Persulfide (Hssh): Possible Molecular Sulfur Sinks In The Dense Ism, Charles Z. Palmer, Ryan C. Fortenberry, Joseph S. Francisco

Faculty and Student Publications

For decades, sulfur has remained underdetected in molecular form within the dense interstellar medium (ISM), and somewhere a molecular sulfur sink exists where it may be hiding. With the discovery of hydrogen peroxide (HOOH) in the ISM in 2011, a natural starting point may be found in sulfur-bearing analogs that are chemically similar to HOOH: hydrogen thioperoxide (HOSH) and hydrogen persulfide (HSSH). The present theoretical study couples the accuracy in the anharmonic fundamental vibrational frequencies from the explicitly correlated coupled cluster theory with the accurate rotational constants provided by canonical high-level coupled cluster theory to produce rovibrational spectra for use …

Go to article

Understanding Biogeochemical And Physical Controls On Methane Air-Sea Exchange Fluxes In The Pacific Ocean, Sarah Raney May 2022

Understanding Biogeochemical And Physical Controls On Methane Air-Sea Exchange Fluxes In The Pacific Ocean, Sarah Raney

Master's Theses

Methane and trace element samples were collected on GEOTRACES GP15 Pacific Meridional Transect (PMT) cruise conducted between the Aleutian Islands (57 °N) and Tahiti (20 °S) from September to November 2018. Uncertainty in methane air-sea exchange fluxes was determined using a propagation of errors approach. Fluxes ranged from -0.88 to 4.9 µmol CH4 m-2 d-1. Average CH4 flux along the Alaskan margin was 2.2 ± 2.9 µmol CH4 m-2 d-1. Methane fluxes decreased moving southward and increased to their open ocean maximum around 20 °N before declining in equatorial waters. Near …

Go to article

Real-Time Monitoring Of Paraquat Photodegradation Using Colloidal Gold Surface Enhanced Raman Spectroscopy, Nathan Wilson May 2022

Real-Time Monitoring Of Paraquat Photodegradation Using Colloidal Gold Surface Enhanced Raman Spectroscopy, Nathan Wilson

Masters Theses & Specialist Projects

Monitoring chemical reactions in aqueous solution is a challenge because most instrumental techniques either are not suited for the rapid timescales, are not sensitive enough to detect products at low concentrations, or do not have sufficient structure-to-spectrum relationships. Raman spectroscopy is a promising method to monitor reactions, as it is fast, dependent on chemical structure, and has little interference from water. However, Raman scattering is generally very weak. Surface-enhanced Raman spectroscopy (SERS) improves the signal strength of Raman spectroscopy by using a metal surface plasmon, or oscillation of the surface’s electrons, to allow for highly selective and sensitive detection and …

Go to article

Stem Club, Camden Jones, Erica Gesner, Amber Gadeken May 2022

Stem Club, Camden Jones, Erica Gesner, Amber Gadeken

Honors Program: Expanded Learning Clubs

The goal of this club is to introduce various topics stemming from different fields in science. We hope to excite the students about science and show them how important it is to their everyday lives. This club also aims to provide free education to underserved communities.

Go to article

Towards The Determination Of Estrone And 17Β-Estradiol In Dairy Cattle Waste Using Solid Phase And Stir Bar Sorptive Extractions With Liquid Chromatography-Mass Spectrometry And Gas Chromatography-Mass Spectrometry, Pallavi Ragi May 2022

Towards The Determination Of Estrone And 17Β-Estradiol In Dairy Cattle Waste Using Solid Phase And Stir Bar Sorptive Extractions With Liquid Chromatography-Mass Spectrometry And Gas Chromatography-Mass Spectrometry, Pallavi Ragi

Masters Theses & Specialist Projects

Steroidal hormones are naturally produced as a part of many physiological processes and are excreted in the urine and feces of animals and humans. Farm animals in concentrated animal feeding operations (CAFOs) are routinely implanted with synthetic and natural hormones to enhance growth and production, contributing significantly to environmental steroid hormone contamination. Every year around 49 tons of estrogens are generated by livestock waste in the United States alone. Due to rainfall and runoff, these steroid hormones reach the environment when animal waste is applied as manure. Studies show that estrogens and other steroidal hormones present in the surface waters …

Go to article

Dynamics Of Chemical Reaction Networks, Igor Vouffo May 2022

Dynamics Of Chemical Reaction Networks, Igor Vouffo

Honor’s College Freeman Research Journal

Network architecture imposes constrains on the types of dynamics a network system admits. Chemical reaction networks have further constrains coming from a special feature of reaction rate functions: the kinetic equations can be written as a product of a constant matrix (stoichiometric matrix) and its kinetics. Such special feature enables us to utilize the existing results from linear algebra to identify network conditions for addressing questions about dynamics. In this thesis, we reviewed some results by M. Feignberg and his collaborators regarding to the graphic conditions for multiplicity of equilibria (constant solutions), and also reviewed a result by Hirono et …

Go to article

First Prev Next Last