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Determination Of Benzotriazole And Analog Compounds By Liquid Chromatography-Mass Spectrometry In Surface Runoff Water Samples From Wilmington Air Park, Jessica A. Wiese

Browse all Theses and Dissertations

Benzotriazole (BTri) and its analog compounds are widely used in aircraft de-icing and anti-icing solutions, however their high solubility in water and resistance to biodegradation results in only their partial removal in wastewater treatment, and therefore makes them potential contaminants in watershed systems. The Wilmington Air Park in Wilmington, Ohio currently has two surface-runoff lagoons to pre-treat water containing these de-icing compounds before releasing it into nearby streams. Because the Wilmington Air Park has recently made an agreement with a major online retailer to lease over two dozen planes and open a package-sorting facility beginning in late 2019, the goal …

Urease Is An Essential Component Of The Acid Response Network Of Staphylococcus Aureus And Is Required For A Persistent Murine Kidney Infection, Chunyi Zhou, Fatema Bhinderwala, Mckenzie K. Lehman, Vinai C. Thomas, Sujata S. Chaudhari, Kelsey J. Yamada, Kirk W. Foster, Robert Powers, Tammy Kielian, Paul D. Fey

Department of Chemistry: Faculty Publications

Staphylococcus aureus causes acute and chronic infections resulting in significant morbidity. Urease, an enzyme that generates NH₃ and CO₂ from urea, is key to pH homeostasis in bacterial pathogens under acidic stress and nitrogen limitation. However, the function of urease in S. aureus niche colonization and nitrogen metabolism has not been extensively studied. We discovered that urease is essential for pH homeostasis and viability in urea-rich environments under weak acid stress. The regulation of urease transcription by CcpA, Agr, and CodY was identified in this study, implying a complex network that controls urease expression in response to changes …

Synthesis, Structure, And Luminescence Properties Of Rare-Earth-Doped Alkaline-Earth Fluorohalide Upconverting Nanocrystals, Kumuduni Tauni Dissanayake

Wayne State University Dissertations

The major scientific problems that associated with the state-of-the-art upconverting nanocrystal system (rare-earth-doped β-NaYF4) are lower quantum efficiency, lack of full-spectrum color tunability, and difficulty in achieving single-band red emission. The major scientific strategies that employed to address these scientific problems are based on nanostructuring, tuning rare-earth concentration, and tuning host chemical composition. The reported articles during the past few decades clearly illustrated that nanostructuring and tuning rare-earth concentration hadn’t bought considerable contribution to synthesize efficient and color-tunable upconverting nanocrystal systems. However, the ability to tune the chemical composition of the host to design efficient and color-tunable upconverting nanocrystal system …

Properties And Applications Of Tetraalkylphosphonium Alkylsulfate Ionic Liquids And 3d Printed Polymerized Ionic Liquids, Mustafa Mohammed Alhussain

Murray State Theses and Dissertations

Ionic liquids (ILs) are defined as pure salts with a melting temperature below 100 °C with a subset called room-temperature ILs (RTILs) with melting temperatures at or below room temperature. The sizes of the cation and anion play a critical role in determining the properties, with smaller ions forming stronger ionic forces and packing better, raising viscosity and lowering conductivity of the IL. At the same time, intermolecular forces such as van der Waals and hydrogen bonding can play a role in IL properties as well. Our research described herein is focused on three tetraalkylphosphonium-based cations coupled with three alkylsulfate …

Design, Synthesis And Biological Screening Of Novel Cucs-Inspired Estrone Analogs Towards Treatment Of Pancreatic Adenocarcinoma, Khaled Alseud

Electronic Theses and Dissertations

Pancreatic cancer is currently the fourth most deadly type of cancer globally. It is expected to become the second by 2030, due to its poor prognosis and its resistance to the current standard treatment, Gemcitabine. Moreover, the survival rate after treatment is low compared to other cancer types, which suggests an urgent need for new potent and safe treatment agents. Recently, the triterpenoid, cucurbitacin, has shown promising antiproliferative activity against human pancreatic cancer cells in a dose- and timedependent manner, and decreased pancreatic tumor size in combination with gemcitabine in vivo. However, the use of cucurbitacin in clinical studies has …

Application Of Analytical Techniques In Food Product Development, Sonali R. Pandey

Electronic Theses and Dissertations

Products are analyzed in major sectors of food industry to meet regulatory standards, food safety, quality control, and research and development. Analytical and extraction techniques have been applied for simultaneous investigation of multiple product characteristics. Food analysis faces critical challenges due to the complex composition of food, leading to matrix effects that result in loss of accuracy and reliability. The analytical techniques require an efficient sample preparation to avoid or minimize matrix effects. Solid-phase extraction has been widely used to address this issue. In this dissertation, the aim is to apply analytical techniques in food product development. To accomplish this, …

Mass Spectrometry-Based Quantitative Proteomic Analysis Of Biological Fluids, Patience Akosua Afedi

Electronic Theses and Dissertations

Proteomics is a high-throughput approach to study protein expression, structure, function, interaction, post-translational modifications, and localization in a cell or tissue. Proteomic shotgun approach was used to analyze changes in proteins in bovine follicular fluid (FF) and plasma (PL) from cows with high estradiol (HE2) or low E2 (LE2) during the preovulatory period. FF creates a unique microenvironment in follicles necessary for follicle growth and oocyte maturation, and pre-ovulatory concentrations of E2 have been reported to impact several processes involved with fertility. Initial steps in the analysis involved development of an immunodepletion protocol for high abundant proteins (HAPs) in bovine …

Effect Of Mineral Ions On The Functional Properties Of Starch Films, Aliza Sigdel

Electronic Theses and Dissertations

Essential minerals are indispensable inorganic micronutrients that modulate vital physiological functions at the molecular level. Their deficiency, though required in small amounts, impairs health significantly. Their supplementation through diet is prudent and carbohydrates standout as favorable choice. Carbohydrates, starches and polysaccharides, exhibit unique chemical structures and functionalities, and interact with mineral ions in several ways. The aim of this research is to investigate the effect of mineral ions on the physicochemical properties, tensile strength and in vitro starch digestion of starch-films. Corn starch and potato starch along with Fe2+, Mn2+, Cu2+ and Zn2+ ions have been chosen as model starch …

In-Silico Design And Synthesis Of Selective Estrogen Receptor Modulators Targeting Ovarian Cancer, John Apraku

Electronic Theses and Dissertations

The established records of the safety of Ormeloxifene along with its favorable bioavailability and ability to inhibit rapid cell proliferation in the endometrium during embryonic implantation has made it one of the best drug candidates for controlling undesirable rapid cell growth such as endometriosis and cancerous tumor conditions. Recent studies have confirmed the effectiveness of Ormeloxifene to suppress and inhibit epithelial-mesenchymal transition process as evidenced by repression of N-cadherin, slug, snail, vimentin, MMPs, β-catenin/TCF-4 transcriptional activity and induce the expression of pGSK3b. Recently conducted studies have revealed the dynamic binding of ormeloxifene with β-catenin, GSK3b, CDK4, and other downstream EGFR. …

การใช้ผลิตภัณฑ์จุลินทรีย์เพื่อการกำจัดสีย้อมรีแอกทีฟในสารละลายสีย้อมที่ใช้แล้ว, ฐิติกานต์ นิลแก้ว

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ได้คัดเลือกผลิตภัณฑ์จุลินทรีย์ทางการค้า 3 ชนิด (ผลิตภัณฑ์จุลินทรีย์ T B และ F) ที่มีแนวโน้มในการกำจัดสีย้อมรีแอกทีฟ ได้แก่ 1)Novacron Super Black-G 2)Novacron Red S-B และ 3)Novacron Orange C-3R จากการทดลองพบว่าผลิตภัณฑ์จุลินทรีย์ B สามารถกำจัดสีในสารละลายสีได้ดีที่สุด และเมื่อศึกษาความสามารถของผลิตภัณฑ์จุลินทรีย์ B ในการกำจัดสีรีแอกทีฟในสารละลายสีที่มีน้ำและสี ทดลองในภาวะต่างๆ ของค่าพีเอช อุณหภูมิและปริมาณจุลินทรีย์ ณ ภาวะสถิตและเขย่า พบว่า ภาวะที่เหมาะสมต่อการกำจัดสีรีแอกทีฟทั้งสามสี คือพีเอช 8 เติมผลิตภัณฑ์จุลินทรีย์ B 0.7 กรัมในสารละลายสีความเข้มข้น 100 มิลลิกรัมต่อลิตร ปริมาตร 100 มิลลิลิตร บ่มที่ภาวะสถิต อุณหภูมิ 40 องศาเซลเซียส เป็นเวลา 6 วัน แล้วนำภาวะที่เหมาะสมเบื้องต้นมาศึกษาความสามารถของผลิตภัณฑ์จุลินทรีย์ B ในการกำจัดสี Novacron Super Black-G ในสารละลายสีที่มีด่างและเกลือพบว่า สามารถกำจัดสารละลายสีที่มีด่างและที่มีด่างและเกลือได้ 87.44 และ 90.61 เปอร์เซ็นต์ตามลำดับ ภายใน 6 วัน ผลการวิเคราะห์คุณภาพน้ำเสียหลังกำจัดสีด้วยผลิตภัณฑ์จุลินทรีย์ B พบว่า ค่าพีเอช ของแข็งละลายน้ำทั้งหมด (Total Dissolved Solids; TDS) และของแข็งแขวนลอยทั้งหมด (Total Suspended Solid; TSS) ไม่เกินมาตรฐานน้ำทิ้งสำหรับอุตสาหกรรมสิ่งทอ ผลการวิเคราะห์โครงสร้างทางเคมีของสีก่อนและหลังกำจัดสีโดยใช้เทคนิค FTIR และ HPLC พบว่า ผลิตภัณฑ์จุลินทรีย์ B สามารถย่อยสลายหมู่โครโมฟอร์หรือหมู่เอโซ (-N=N-) ทำให้พันธะเอโซของสีแตกออกแล้วเกิดเป็นสารแอโรแมติกเอมีน ทำให้ความเข้มสีลดลง ในขณะที่ผลการวิเคราะห์กรดออกซาลิกที่อาจเกิดขึ้นจากการย่อยสลายสี Novacron Super Black-G ของผลิตภัณฑ์จุลินทรีย์ B พบว่าไม่สามารถตรวจสอบด้วยเทคนิค HPLC …

Fluorescence-Based Ratiometric Nanosensor For Selective Imaging Of Cancer Cells, Isiah M. Warner, Kelsey E. Mcneel, Noureen Siraj, Nimisha Bhattarai

Faculty Publications

Herein, we report the synthesis and characterization of a nanosensor developed from a group of uniform materials based on organic salts (GUMBOS). This sensor is composed of three ionic species, namely, fluorescein, rhodamine B, and tetradecyltrihexyl phosphonium (P-66614) ions. Nanoparticles prepared from this three-component GUMBOS, termed nanoGUMBOS, exhibited increased fluorescence at two wavelengths with increases in pH values. The ratio of fluorescence emission corresponding to FL and RhB components of these nanoGUMBOS also changed with pH, allowing ratiometric analysis of pH through fluorescence measurements. Peak ratios were significantly different at pH 5 and pH 7, indicating potential applications of this …

Synthesis And Investigation Of Phthalocyanine-Biotin Conjugates, M. Graca H. Vicente, Elizabeth A. Okoth, Zehua Zhou, Benson Ongarora

Faculty Publications

An isothiocyanato-functionalized phthalocyanine (Pc) was synthesized in good yield from the corresponding amine-substituted Pc. This Pc reacted with ethanolamine, biotin hydrazine, and biotin diethylamine under mild conditions (room temperature in DMF or DMSO in the presence of TEA) to produce the corresponding thiourea products in 60-75% yields. All Pcs showed intense Q absorptions in DMF around 677 nm, emissions centered at 683 nm, and fluorescence quantum yields in the range 0.18-0.27. The Pcs were phototoxic to human carcinoma HEp2 cells (IC50 similar to 7 at 1.5 J/cm(2)) and localized in multiple organelles, including the lysosomes, Golgi and ER. One biotin-Pc …

การสังเคราะห์ 5-ไฮดรอกซีเมทิลเฟอร์ฟิวรัลจากกลูโคสโดยใช้ตัวเร่งปฏิกิริยาซีโอไลต์ Husy, พิมลพรรณ เล็กสมบูรณ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาการดัดแปรสภาพกรดของซีโอไลต์ HUSY ผ่านการล้างด้วยสารละลายกรด และศึกษาการสังเคราะห์ 5-ไฮดรอกซีเมทิลเฟอร์ฟิวรัล (HMF) จากกลูโคสโดยใช้ซีโอไลต์ HUSY เป็นตัวเร่งปฏิกิริยา ในการสังเคราะห์ HMF จากกลูโคสเกิดผ่านปฏิกิริยา 2 ขั้นตอน ได้แก่ ปฏิกิริยาไอโซเมอไรเซชันของกลูโคสเป็นฟรุกโตส และปฏิกิริยาดีไฮเดรชันของฟรุกโตสไปเป็น HMF โดยใช้ตัวเร่งปฏิกิริยากรดชนิดลิวอิส และกรดชนิดกรดบรอนสเตดตามลำดับ จากการศึกษาสมบัติทางกายภาพและเคมีของซีโอไลต์ HUSY พบว่าซีโอไลต์ HUSY ที่ผ่านการดัดแปรสภาพกรดมีปริมาณอะลูมิเนียมลดลง พร้อมกับเกิดการสูญเสียโครงสร้างผลึกซีโอไลต์ จากการศึกษาหมู่ฟังก์ชันพบว่าซีโอไลต์ HUSY ที่ผ่านการแปรสภาพกรดมีหมู่ฟังก์ชันหมู่ไฮดรอกซิลของตำแหน่งกรดชนิดบรอนสเตดและกรดชนิดลิวอิสที่เปลี่ยนแปลงไป และจากการศึกษาสภาพกรดของซีโอไลต์ HUSY ที่ผ่านการแปรสภาพกรด พบว่ามีแนวโน้มของปริมาณกรดรวมลดลง ขณะที่สัดส่วนของปริมาณตำแหน่งกรดแก่มีแนวโน้มเพิ่มขึ้น และปริมาณตำแหน่งกรดชนิดบรอนสเตดและกรดชนิดลิวอิสมีแนวโน้มเพิ่มขึ้น ในการสังเคราะห์ HMF จากกลูโคส พบว่าการเปลี่ยนกลูโคสมีความสัมพันธ์กับปริมาณตำแหน่งกรดแก่ในตัวเร่งปฏิกิริยาซีโอไลต์ HUSY และผลได้ของ HMF มีความสัมพันธ์กับสัดส่วนระหว่างปริมาณตำแหน่งตำแหน่งกรดชนิดบรอนสเตดกับกรดชนิดลิวอิส (สัดส่วน B/L) ซึ่งพบว่าตัวเร่งปฏิกิริยาซีโอไลต์ HUSY-0.1N-80 ที่มีสัดส่วน B/L เท่ากับ 3.17 ทำให้ได้ผลได้ของ HMF สูงที่สุด และสภาวะการสังเคราะห์ HMF พบว่าตัวเร่งปฏิกิริยาซีโอไลต์ HUSY-0.1N-80 ปริมาณ 0.25 กรัม สังเคราะห์ที่อุณหภูมิ 170 องศาเซลเซียสเป็นระยะเวลา 60 นาที เป็นสภาวะที่เหมาะสมที่สุด โดยมีการเปลี่ยนของกลูโคส และผลได้ของ HMF เท่ากับ 99.6% และ 65.6% ตามลำดับ

Structure And Dynamics Of Spin Label Side Chains In Membrane Protein Using Molecular Dynamics Simulations, Ngoc-Lan Le-Nguyen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Site-directed spin labeling (SDSL) combined with electron paramagnetic resonance (EPR) spectroscopy is a powerful approach to explore the structure and dynamics of biological complex systems. Nitroxide spin label is the most widely used probe for SDSL in the study of structure and function of biomolecules. However, the behavior of the nitroxide spin label is not well understood. This study aims to characterize the structural and dynamical properties of the spin label in the voltage-sensing domain (VSD) of KvAP, a potassium channel from the thermophilic archaea Aeropyrum pernix by mean of molecular dynamics (MD) studies. MD simulations for unlabeled and a …

Conformational Flexibility In The Enterovirus Rna Replication Platform, Meghan S. Warden, Kai Cai, Gabriel Cornilescu, Jordan E. Burke, Komala Ponniah, Samuel E. Butcher, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

A presumed RNA cloverleaf (5′CL), located at the 5′-most end of the noncoding region of the enterovirus genome, is the primary established site for initiation of genomic replication. Stem–loop B (SLB) and stem–loop D (SLD), the two largest stem–loops within the 5′CL, serve as recognition sites for protein interactions that are essential for replication. Here we present the solution structure of rhinovirus serotype 14 5′CL using a combination of nuclear magnetic resonance spectroscopy and small-angle X-ray scattering. In the absence of magnesium, the structure adopts an open, somewhat extended conformation. In the presence of magnesium, the structure compacts, bringing SLB …

Synthesis, Characterization And Mechanistic Studies Of Biomimetic Dinuclear Copper(Ii) Complexes, Millaniyage Nuwanthaka Prasad Jayaweera

Masters Theses

Dinuclear copper complexes are significant synthetic targets due to their use as model compounds for the active sites of type 3 copper proteins like catechol oxidase. A distinct class of ligands used in these studies are built on a phenol core to witch various donor side-arms were appended at the 2 and 6 positions of the arene ring. In our quest to quantify the influence of electron donating or withdrawing groups attached to the central arene ring, we have designed a set of ligands that, upon coordination to copper(II) centers, would produce complexes of the general structure. During this research …

Developing A Basket-Shaped Host Molecule Based On P-Tert-Butylcalix[4]Arene Featuring Urea Groups For Encapsulating Volatile Guest Molecules, Lokugama Widanelage Vidula Priyadarshana

Masters Theses

Molecular baskets are a group of synthetic host molecules which are designed to govern the inclusion of small guest molecules. The basic structural features of basket-shaped host molecules are a cavity for holding a much smaller guest molecule and tunable gates for keeping the guest molecule inside. These types of gates can be tuned by changing temperature, concentration, pH, etc. In this research group's previous study, a molecular basket of cal ix[ 4]arene with carboxylic acid groups was synthesized by functionalizing calix[4]arene's phenol hydroxyl groups with benzyl bromide building blocks. In the study detailed here, 1 , l '-((5-(bromomethyl)-1,3-phenylene)bis(methylene))bis(3-isopropylurea) was …

Applications Of Chemically Modified Nitrogen Doped Carbon, Zirconium Phosphate, Metal Organic Frameworks, And Functionalized Graphene Oxide Nanostructured Adsorbents In Water Treatment, Ayyob Mohammed A Bakry

Theses and Dissertations

Water contaminations by many pollutants, especially heavy metals such as Pb(II), Hg(II), Cu(II), Cd(II), and Cr(VI) pose many public health and environmental concerns as reported in the list of hazardous substances compiled by the US Environmental Protection Agency due to their high toxicity, refractory degradation, and ease of entering food chain. Adsorption by chelating resins is proven to be the most effective method for the extraction of metal ions from polluted and wastewater. However, traditional absorbents such as activated carbon, activated alumina, clay, zeolite, etc., show limited adsorption abilities for these heavy metal ions. The major goal of this thesis …

An Enzymology And Inhibition Study Of A Camp-Dependent Protein Kinase Linked To Acth-Independent Cushing's Syndrome, Nicole Luzi

Theses and Dissertations

Cyclic-AMP dependent protein kinase (PKA) is a key intracellular signal transduction kinase that is modulated by G_s- and G_i-coupled GPCRs. Under normal physiological conditions, PKA exists as an inactive holoenzyme made up of two catalytic subunits and two regulatory subunits. Upon cAMP binding to the regulatory subunits, the catalytic subunits (PKACa) are released to perform various downstream phosphorylation events. However, aberrant PKA activation can cause various diseases including Cushing’s Syndrome, which is an endocrine disorder caused by the overproduction of cortisol by the hypothalamus-pituitary-adrenal hormone system. This disorder can be caused by pituitary adenomas that release …

Expansion Of The Genetic Code To Include Acylated Lysine Derivatives And Photocaged Histidine, William D. Kinney

Theses and Dissertations

The genetic code of all known organisms is comprised of the 20 proteinogenic amino acids that serve as building blocks on a peptide chain to form a vast array of proteins. Proteins are responsible for virtually every biological process in all organisms; however, the 20 amino acids contain a limited number of functional groups that often leaves much to be desired. The lack of diversity addresses the need to increase the genetic repertoire of living cells to include a variety of amino acids with novel structural, chemical, and physical properties not found in the common 20 amino acids. In order …

Biometal-Induced Structural Consequences Of Α-Synuclein – The Parkinson’S Disease Protein, Dinendra L. Abeyawardhane

Theses and Dissertations

The pre-synaptic protein α-Synuclein (αS) is often linked to the pathology of Parkinson’s disease (PD), an age-related neurodegenerative disorder. Lewy bodies, the cytopathological hallmarks of PD, are found to be rich in aggregates of misfolded αS protein. Metal dyshomeostasis has also been linked to PD due to the accumulation of iron in the substantia nigra pars compacta, and diminished copper levels reported in this same region. Metal dyshomeostasis in the brain coupled with oxidative stress can enhance the aggregation of αS. Recently, it was confirmed that mammalian αS is universally acetylated at the N-terminus, a common post-translational modification in …

The Development Of Intrinsically Cell-Permeable Peptide Libraries Using Mrna Display, Nicolas A. Abrigo

Theses and Dissertations

Peptides are emerging as promising therapeutics due to their inhibitory affinity towards protein-protein interactions (PPI). However, peptides have been limited mainly by their poor bio-stability and lack of cell permeability. Efforts to generate drug-like peptides have led to the development of macrocyclic peptides, which exhibit improved stability. Yet, most macrocyclic peptides still require the assistance of a cell penetrating peptide (CPP) for cellular entry.

High throughput technologies have been exceptional tools for the discovery of peptides to interrupt PPIs. This work details the recent advancements we have made to improve our high throughput technique, mRNA display, to yield more therapeutically …

Near-Infrared High Efficiency Organic Dye Sensitized Solar Cells (Dscs) And Biological Fluorescent Imaging Dyes, Yanbing Zhang

Electronic Theses and Dissertations

With the energy consumption increase every year, the non-renewable energy sources such as fossil fuels, natural gas, and coal will not sustain forever. In this case, searching for a way to develop a renewable energy source is an emergency. For decades, dye-sensitized solar cells (DSCs) have received intensive attention due to their high power conversion efficiency and low material cost. This dissertation describes efforts to design and synthesize near-infrared organic dyes to apply to two systems: first, for use in the improvement of DSCs by the optimization of electron rich components such as ullazine and cross-conjugated -bridges to increase photon-to-electricity …

Advanced Analysis Of Compounds Of Toxicological Importance By Ice Concentration Linked With Extractive Stirrer (Icecles) Gc-Ms And Rp-Hplc-Esi-Ms-Ms, Joseph K. Dzisam

Electronic Theses and Dissertations

Cyanide and nitrosoamines (NAs) are ubiquitous compounds, found in our food and water, either by natural process or through man-made activities. The toxicity of cyanide is exerted by its ability to inhibit metalloenzymes such as cytochrome c oxidase, causing concomitant cascades of biochemical effects such as lactic acidosis, inhibition of ATP production, respiratory seizure, and potential death. Nitrosoamines, on the other hand, undergo biotransformation (metabolic activation in cytochrome P450) in the body to produce unstable intermediates that alkylate DNA, causing mutations, and leading to carcinogenesis. In order to further the advancement of a promising cyanide, cobinamide (Cbi), an LC-MS-MS method …

Case Studies Of Potential Reference Materials In Cultural Heritage Science, Heidi Kastenholz

Undergraduate Honors Thesis Collection

The study of cultural heritage objects requires reference materials for comparison in order to determine the identity of chemical compounds in historically/culturally significant artifacts. The reference materials available today can be inaccurately labeled, can contain inauthentic compounds, or can simply be formed differently than what the labeled material should be. Utilizing the laboratory at the Indianapolis Museum of Art at Newfields, three case studies were conducted over three different potential reference materials in order to properly identify each of the three materials being focused on here. Based on the analysis, the labels for these materials often do not match the …

Assessment Of Quantity And Quality Of Microplastics In The Sediments, Waters, Oysters, And Selected Fish Species In Key Sites Along The Bombong Estuary And The Coastal Waters Of Ticalan In San Juan, Batangas, Emilyn Q. Espiritu, Sophia Angeli Sn Dayrit, Annabel Soledad O. Coronel, Natasha Sophia C. Paz, Pilar Isabel L. Ronquillo, Virgil Christian G. Castillo, Erwin P. Enriquez

Chemistry Faculty Publications

Microplastics (or MPs; < 5 mm in size) pollution is largely unstudied in the Philippines. From an environmental sustainability standpoint, it is important to understand the characteristics, abundance, and environmental fate of plastic debris of various sizes, and these include microplastics that are not more easily and readily detected. In this study, we assessed the extent of microplastics contamination in the sediments, waters, oysters, and selected fishes found in the rivers and coastal areas of Ticalan, Batangas, which were identified from water quality parameters as Class C and CS, respectively. The microplastics were extracted from these samples by chemical digestion of the matrix, series of filtration, and separation by flotation through a density gradient to finally isolate the microplastics which were not dissolved by chemical digestion. The isolated samples were imaged by optical microscopy and characterized based on their descriptive attributes. The results showed the presence of microplastics in all the samples tested, which were found mostly in the form of filaments, fragments, films, and pellets – with most showing weathered, degraded, or angular and irregular surfaces. Identification was done through spectral matching of the Fourier transform infrared spectra of isolated fragments with that of known plastics, although identification in some cases is made uncertain by possibility of degradation of the plastics in the environment. The majority of the isolates showed signature absorption bands of the C-H stretching vibrations of polyethylene-based plastics.

Molecular Memory With Downstream Logic Processing Exemplified By Switchable And Self-Indicating Guest Capture And Release, Brian Daly, Thomas S. Moody, Allen J.M. Huxely, Chaoyi Yao, Benjamin Schazmann, Andre Alves-Areias, John F. Malone, H.Q. Nimal Gunaratne, Peter Nockemann, A. Prasanna De Silva

Articles

Molecular-logic based computation (MLBC) has grown by accumulating many examples of combinational logic gates and a few sequential variants. In spite of many inspirations being available in biology, there are virtually no examples of MLBC in chemistry where sequential and combinational operations are integrated. Here we report a simple alcohol-ketone redox interconversion which switches a macrocycle between a large or small cavity, with erect aromatic walls which create a deep hydrophobic space or with collapsed walls respectively. Small aromatic guests can be captured or released in an all or none manner upon chemical command. During capture, the fluorescence of the …

Modified Surface Relief Layer Created By Holographic Lithography: Application To Selective Sodium And Potassium Sensing, Sabad-E Gul, Luke O'Neill, John Cassidy, Izabela Naydenova

Articles

Point-of-care diagnostics will rely upon the development of low-cost, noncomplex, and easily integrated systems in order to examine biological samples such as blood and urine obtained from the patient. The development of metal ion sensors is a subject of significant relevance for physiological samples. The level of different blood electrolytes, mainly H+, Na+, K+ and Cl− is considerably used to monitor irregular physiologies. The particular challenge in biosensing, and in fact for any other sensor, is signal differentiation between non-specifically bound material and the specific detecting of the target molecule/ion. The biosensors described in this paper are fabricated by a …

Highly Selective Fluorimetric Turn-Off Detection Of Copper (Ii) By Two Different Mechanisms In Calix[4]Arene-Based Chemosensors And Chemodosimeters, Justine O'Sullivan, John Colleran, Brendan Twamley, Frances Heaney

Articles

Isoxazolo‐pyrene tethered calix[4]arenes selectively detect copper(II) ions without interference from related perchlorate ions. The fluorescence emission of the probes, synthesised by nitrile oxide alkyne cycloaddition, and characterised by spectroscopic and crystallographic data, is rapidly reduced by Cu(II) ions. Detection limits are in the micromolar or sub‐micromolar range (0.3–3.6 μM) based on a 1 : 1 sensor:analyte interaction. Voltammetric behaviour and 1H NMR data provide new insights into the sensing mechanism which is dependent on the calixarene substitution pattern. When the calixarene lower rim is fully substituted, Cu(II) detection occurs through a traditional chelation mechanism. In contrast, for calixarenes 1,3‐disubstituted on …

The Role Of Plant Proteins In The Green Synthesis Of Silver Nanoparticles, Katherine Trausch, Jeffrey Wiemer, Anna Holmes

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.