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2023

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Articles 1171 - 1200 of 1539

Full-Text Articles in Chemistry

Split Catalytic Probes For The Detection Of Monkeypox Virus, Jaehyun Ahn Jan 2023

Split Catalytic Probes For The Detection Of Monkeypox Virus, Jaehyun Ahn

Honors Undergraduate Theses

The COVID-19 outbreak highlighted the important role that diagnostic tests play in the healthcare system. To reduce the impact of infectious disease outbreaks, the development of rapid and cost-effective point-of-care-tests (POCTs) is crucial. With the dissemination of the Monkeypox (Mpox) virus, it became a necessity to produce POCTS that are inexpensive and easy to use. This work explored the construction of two colorimetric assays that aim to detect Mpox genetic signatures. One is based on the split-peroxidase-like deoxyribozyme probes (sPDz), while the other utilizes a cascade system of split RNA-cleaving deoxyribozyme (sDz) and peroxidase-like deoxyribozyme (PDz). Both rely on catalytic …

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Literature Search For Extraction And Characterization Of Fragrant Compounds From Ten Flowering Plants, Ember Smith Jan 2023

Literature Search For Extraction And Characterization Of Fragrant Compounds From Ten Flowering Plants, Ember Smith

All Capstone Projects

This capstone literature project conducted a literature search on the extraction of essential oils from the leaves of ten different flowering plants using steam distillation and/or solvent extraction methods. Additionally, the project focused on characterizing and identifying the fragrant compounds present in the essential oils of these ten plants. By conducting a comprehensive literature search, this project provides a summary of the methods employed for extraction and the composition of fragrant compounds in each essential oil. A diverse range of fragrant compounds were found in various plants and flowers, including major and minor compounds such as alcohols, aldehydes, ketones, terpenes, …

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A Comparison Of Tung Oil Resin Reinforcements Using Fibrous Proteins And Peptides For Biological And Materials Applications, Parker L. Williams Jan 2023

A Comparison Of Tung Oil Resin Reinforcements Using Fibrous Proteins And Peptides For Biological And Materials Applications, Parker L. Williams

College of Graduate Studies: Theses & Dissertations

In this study a tung oil based thermoset was reinforced with collagen and fibroin, and the resulting composites were analyzed for their physical properties. Tung tree seed oil is a great candidate for biobased polymer production because its triglycerides are primarily made of alpha eleostearic acid, a fatty acid with three conjugated carbon-carbon double bonds. These double bonds allow for mechanically strong crosslinking in the polymer. It has been observed that polymerized tung oil forms a gel. This issue has been addressed using divinylbenzene (DVB) and n-butyl methacrylate (BMA) as co-monomers. Similar bio-based polymers have been studied and tend to …

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Development And Praxis Of Ph Drug Delivery System Contra Zika, Julissa Rodriguez Jan 2023

Development And Praxis Of Ph Drug Delivery System Contra Zika, Julissa Rodriguez

College of Graduate Studies: Theses & Dissertations

As the effects of global warming continue to spread throughout the world, another critical issue is slowly gaining attention in many urban tropical countries. The Emerging Infectious Diseases/ Pathogens list from the National Institutes of Health (NIH) listed the Zika virus as a potential pandemic threat. In 2015, an outbreak of Zika was noted in several South American countries until the spread reached an all-time high of 87 countries in 2017. During the outbreaks, adults affected were noted to have joint and muscle pains, fevers, and rashes. The worst cases reported would ultimately lead to Guillain-Barre symptoms. Still, pregnant women …

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Structure–Activity Relationship Studies On 6-Chloro-1-Phenylbenzazepines Leads To The Identification Of A New Dopamine D1 Receptor Antagonist, Rajan Giri, Hari K. Namballa, Vishwashiv Emogaje, Wayne W. Harding Jan 2023

Structure–Activity Relationship Studies On 6-Chloro-1-Phenylbenzazepines Leads To The Identification Of A New Dopamine D1 Receptor Antagonist, Rajan Giri, Hari K. Namballa, Vishwashiv Emogaje, Wayne W. Harding

Publications and Research

The 1-phenylbenzazepine template has yielded a number of D1R-like ligands, which, though useful as pharmacological tools, have significant drawbacks in terms of selectivity versus D5R as well as pharmacokinetic behavior. A number of 1-phenylbenzazepines contain a 6-chloro functional group, but extensive SAR studies around the 6-chloro-1-phenylbenzazepine framework have not been reported in the literature. To further understand the tolerance of the 6-chloro-1-phenylbenzazepine template for various substituent groups towards affinity and selectivity at D1R, we synthesized two series of analogs with structural variations at the C-7, C-8, N-3, C-3′ and C-4′ positions. The series 2 analogs differed from …

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Comparative Static And Dynamic Analyses Of Solvents For Removal Of Asphaltene And Wax Deposits Above- And Below-Surface At An Iranian Carbonate Oil Field, Milad Norouzpour, Amin Azdarpour, Rafael M. Santos, Ali Esfandiarian, Moein Nabipour, Erfan Mohammadian, Abbas K. Manshad, Alireza Keshavarz Jan 2023

Comparative Static And Dynamic Analyses Of Solvents For Removal Of Asphaltene And Wax Deposits Above- And Below-Surface At An Iranian Carbonate Oil Field, Milad Norouzpour, Amin Azdarpour, Rafael M. Santos, Ali Esfandiarian, Moein Nabipour, Erfan Mohammadian, Abbas K. Manshad, Alireza Keshavarz

Research outputs 2022 to 2026

During production from oil wells, the deposition of asphaltene and wax at surface facilities and porous media is one of the major operational challenges. The crude oil production rate is significantly reduced due to asphaltene deposition inside the reservoir. In addition, the deposition of these solids inside the surface facilities is costly to oil companies. In this study, the efficiency of different solvents in dissolving asphaltene and wax was investigated through static and dynamic tests. The analysis of solid deposits from the surface choke of one of the Iranian carbonate oil fields showed that they consisted of 41.3 wt % …

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Flipping The Thinking On Equality, Diversity, And Inclusion. Why Edi Is Essential For The Development And Progression Of The Chemical Sciences: A Case Study Approach, M. Anwar H. Khan, Timothy G. Harrison, Magdalena Wajrak, Michele Grimshaw, Kathy G. Schofield, Alison J. Trew, Kulvinder Johal, Jeannette Morgan, Karen L. Shallcross, Joyce D. Sewry, Michael T. Davies-Coleman, Dudley E. Shallcross Jan 2023

Flipping The Thinking On Equality, Diversity, And Inclusion. Why Edi Is Essential For The Development And Progression Of The Chemical Sciences: A Case Study Approach, M. Anwar H. Khan, Timothy G. Harrison, Magdalena Wajrak, Michele Grimshaw, Kathy G. Schofield, Alison J. Trew, Kulvinder Johal, Jeannette Morgan, Karen L. Shallcross, Joyce D. Sewry, Michael T. Davies-Coleman, Dudley E. Shallcross

Research outputs 2022 to 2026

All learners have a contribution to make to the development of the Chemical Sciences, be that in novel ways to teach, and their perspectives and contexts, but also in research, both in chemical education and the wider Chemical Sciences. Through four case studies, this paper explores interactions with diverse groups and how this has altered perspectives on both teaching and research. The case studies include work with visually impaired adults, a project bringing together First Peoples in Australia with academics to explore old ways (traditional science) and new ways (modern approaches), primary (elementary) school perspectives on teaching science, and a …

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Spatial And Temporal Varitations In Dissolved Calcium In The Kentucky Lake Watershed In Relation To Zebra Mussel Colonization, Kelsie Meystedt Jan 2023

Spatial And Temporal Varitations In Dissolved Calcium In The Kentucky Lake Watershed In Relation To Zebra Mussel Colonization, Kelsie Meystedt

Murray State Theses and Dissertations

Calcium is the fifth most abundant element on earth’s crust. Plants and animals require calcium for structure and intracellular metabolism. Recent studies have shown that dissolved calcium (Ca2+) freshwater ecosystems is of growing concern as the increasing concentrations of this element are implicated in altering the natural environment and biota. Elevated levels of dissolved calcium and sporadic re-emergence of an invasive species, namely zebra mussels (Dreissena polymorpha) in Kentucky Lake in the recent years served as a motivation for this study. The objective of this study was to determine spatial and temporal variations in dissolved calcium in selected streams, Kentucky …

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Ongoing Fragmentation Of The Subducting Cocos Slab, Central America, Tu Xue, Diandian Peng, Kelly H. Liu, Jonathan Obrist-Farner, Marek Locmelis, Stephen S. Gao, Lijun Liu Jan 2023

Ongoing Fragmentation Of The Subducting Cocos Slab, Central America, Tu Xue, Diandian Peng, Kelly H. Liu, Jonathan Obrist-Farner, Marek Locmelis, Stephen S. Gao, Lijun Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Fundamental to plate tectonics is the subduction of cold and mechanically strong oceanic plates. While the subducted plates are conventionally regarded to be impermeable to mantle flow and separate the mantle wedge and the sub slab region, isolated openings have been proposed. by combining new shear wave splitting measurements with results from geodynamic modeling and recent seismic tomography and geochemical observations, we show that the upper ~200 km of the Cocos slab in northern Central America is intensively fractured. the slab there is strong enough to produce typical arc volcanoes and Benioff Zone earthquakes but allows mantle flow to traverse …

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Erratum: New Estimates Of The Magnitude Of The Sea-Level Jump During The 8.2 Ka Event, (Geology (2022), 50(1), (86–90), (10.1130/G49296.1)), Jonathan Obrist-Farner, Mark Brenner, Jeffery R. Stone, Marta Wojewódka-Przybył, Thorsten Bauersachs, Andreas Eckert, Marek Locmelis, Jason H. Curtis, Susan R.H. Zimmerman, Alex Correa-Metrio, Lorenz Schwark, Edward Duarte, Antje Schwalb, Etienne Niewerth, Paula Gabriela Echeverría-Galindo, Liseth Pérez Jan 2023

Erratum: New Estimates Of The Magnitude Of The Sea-Level Jump During The 8.2 Ka Event, (Geology (2022), 50(1), (86–90), (10.1130/G49296.1)), Jonathan Obrist-Farner, Mark Brenner, Jeffery R. Stone, Marta Wojewódka-Przybył, Thorsten Bauersachs, Andreas Eckert, Marek Locmelis, Jason H. Curtis, Susan R.H. Zimmerman, Alex Correa-Metrio, Lorenz Schwark, Edward Duarte, Antje Schwalb, Etienne Niewerth, Paula Gabriela Echeverría-Galindo, Liseth Pérez

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

No abstract provided.

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Analysis Of Polycyclic Aromatic Hydrocarbons In Tobacco Related Samples Via High Performance Liquid Chromatography And Laser Excited Time Resolved Shpol' Skii Spectroscopy, Ahmed Comas Jan 2023

Analysis Of Polycyclic Aromatic Hydrocarbons In Tobacco Related Samples Via High Performance Liquid Chromatography And Laser Excited Time Resolved Shpol' Skii Spectroscopy, Ahmed Comas

Electronic Theses and Dissertations, 2020-2023

Human exposure to polycyclic aromatic hydrocarbons (PAHs) due to cigarette smoke is well known. It is also known that PAHs are not inherent components of tobacco. Their presence in cigarette smoke results from the curing process of tobacco leaves used for the fabrication of cigarettes and the incomplete combustion of tobacco during the smoking process. The two chromatographic versions of EPA method 610 are popular approaches for the analysis of PAHs in a wide variety of samples. This method, which is based either on High-Performance Liquid-Chromatography (HPLC) or Gas-Chromatography (GC) has shown the presence of Benzo[a]pyrene (B[a]P) in tobacco samples …

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Mechanism Of Pth Ca2+ Sensing On G-Protein Interactions With Pth1r, Difei Jiang Jan 2023

Mechanism Of Pth Ca2+ Sensing On G-Protein Interactions With Pth1r, Difei Jiang

Lawrence University Honors Projects

Parathyroid hormone 1 receptor (PTH1R) is a family-B GPCR that plays a crucial role in bone remodeling. Previous studies show extracellular Ca2+ is a positive allosteric modulator for one PTH1R ligand, parathyroid hormone (PTH), which is approved by US FDA to treat severe osteoporosis. Moreover, PTH residues E19 & E22 have shown to be involved in Ca2+ sensing. However, the effects of PTH Ca2+ sensing on intracellular G-protein binding are unknown. Here, we used FRET-based SPASM sensors to study the interaction between PTH1R and different Ga peptides. SPASM sensors, which are isolated in native HEK293T membranes through optimized protocol, contain …

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Interactions Of Bioactive Trace Metals In Shipboard Southern Ocean Incubation Experiments, Shannon M. Burns, Randelle M. Bundy, William Abbott, Zuzanna Abdala, Alexa R. Sterling, P. Dreux Chappell, Bethany D. Jenkins, Kristen N. Buck Jan 2023

Interactions Of Bioactive Trace Metals In Shipboard Southern Ocean Incubation Experiments, Shannon M. Burns, Randelle M. Bundy, William Abbott, Zuzanna Abdala, Alexa R. Sterling, P. Dreux Chappell, Bethany D. Jenkins, Kristen N. Buck

OES Faculty Publications

In the Southern Ocean, it is well‐known that iron (Fe) limits phytoplankton growth. Yet, other trace metals can also affect phytoplankton physiology. This study investigated feedbacks between phytoplankton growth and dissolved Fe, manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd) concentrations in Southern Ocean shipboard incubations. Three experiments were conducted in September–October 2016 near the West Antarctic Peninsula: Incubations 1 and 3 offshore in the Antarctic Circumpolar Current, and Incubation 2 inshore in Bransfield Strait. Additions of Fe and/or vitamin B12 to inshore and offshore waters were employed and allowed assessment of metal (M) …

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Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins Jan 2023

Potential Interactions Between Diatoms And Bacteria Are Shaped By Trace Element Gradients In The Southern Ocean, Alexa R. Sterling, Laura Z. Holland, Randelle M. Bundy, Shannon M. Burns, Kristen N. Buck, P. Dreux Chappell, Bethany D. Jenkins

OES Faculty Publications

The growth of diatoms in the Southern Ocean, especially the region surrounding the West Antarctic Peninsula, is frequently constrained by low dissolved iron and other trace metal concentrations. This challenge may be overcome by mutualisms between diatoms and co-occurring associated bacteria, in which diatoms produce organic carbon as a substrate for bacterial growth, and bacteria produce siderophores, metal-binding ligands that can supply diatoms with metals upon uptake as well as other useful secondary compounds for diatom growth like vitamins. To examine the relationships between diatoms and bacteria in the plankton (diatom) size class (> 3 mu m), we sampled both …

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Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams Jan 2023

Atmospheric Input And Seasonal Inventory Of Dissolved Iron In The Sargasso Sea: Implications For Iron Dynamics In Surface Waters Of The Subtropical Ocean, Peter N. Sedwick, Bettina M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, Tara E. Williams

OES Faculty Publications

Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time-series Study region and weekly-scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to >1 nM in late summer, …

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Systemic Analyses Of Radiocarbon Ages Of Coexisting Planktonic Foraminifera, Jörg Lippold, Julia Gottschalk, Jean Lynch-Stieglitz, Matthew W. Schmidt, Sönke Szidat, Andre Bahr Jan 2023

Systemic Analyses Of Radiocarbon Ages Of Coexisting Planktonic Foraminifera, Jörg Lippold, Julia Gottschalk, Jean Lynch-Stieglitz, Matthew W. Schmidt, Sönke Szidat, Andre Bahr

OES Faculty Publications

We compare radiocarbon (14C) ages of coexisting planktonic foraminifera species from sediment cores VM12-107 and KNR166-2-26JPC from the Equatorial Atlantic Ocean for three time periods (Holocene, Heinrich Stadial 1, last glacial maximum). We find a maximum inter-species difference of 1200 14C yr. On average, the 14C ages deviate by ∼300 yr between Globigerinoides ruber and other species. In most cases, this exceeds the analytical uncertainty range of the measurements and thus renders the choice of species for generating age models as important as sample weight. While modern stratified water-column profiles imply an increase in 14C …

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Global Oceanic Diazotroph Database Version 2 And Elevated Estimate Of Global N2 Fixation, Zhibo Shao, Yangchun Xu, Hua Wang, Weicheng Luo, Lice Wang, Yuhong Huang, Nona Sheila R. Agawin, Ayaz Ahmed, Mar Benavides, Mikkel Bentzon-Tilia, Ilana Berman-Frank, Hugo Berthelot, Isabelle C. Biegala, Mariana B. Bif, Antonio Bode, Sophie Bonnet, Deborah A. Bronk, Mark V. Brown, Lisa Campbell, Ya-Wei Luo Jan 2023

Global Oceanic Diazotroph Database Version 2 And Elevated Estimate Of Global N2 Fixation, Zhibo Shao, Yangchun Xu, Hua Wang, Weicheng Luo, Lice Wang, Yuhong Huang, Nona Sheila R. Agawin, Ayaz Ahmed, Mar Benavides, Mikkel Bentzon-Tilia, Ilana Berman-Frank, Hugo Berthelot, Isabelle C. Biegala, Mariana B. Bif, Antonio Bode, Sophie Bonnet, Deborah A. Bronk, Mark V. Brown, Lisa Campbell, Ya-Wei Luo

OES Faculty Publications

Marine diazotrophs convert dinitrogen (N2) gas into bioavailable nitrogen (N), supporting life in the global ocean. In 2012, the first version of the global oceanic diazotroph database (version 1) was published. Here, we present an updated version of the database (version 2), significantly increasing the number of in situ diazotrophic measurements from 13 565 to 55 286. Data points for N2 fixation rates, diazotrophic cell abundance, and nifH gene copy abundance have increased by 184 %, 86 %, and 809 %, respectively. Version 2 includes two new data sheets for the nifH gene copy abundance of non-cyanobacterial …

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Isotopic Evidence For Sources Of Dissolved Carbon And The Role Of Organic Matter Respiration In The Fraser River Basin, Canada, Britta M. Voss, Timothy I. Eglinton, Bernhard Peucker-Ehrenbrink, Valier Galy, Susan Q. Lang, Cameron Mcintyre, Robert G.M. Spencer, Ekaterina Bulygina, Zhaohui Aleck Wang, Katherine A. Guay Jan 2023

Isotopic Evidence For Sources Of Dissolved Carbon And The Role Of Organic Matter Respiration In The Fraser River Basin, Canada, Britta M. Voss, Timothy I. Eglinton, Bernhard Peucker-Ehrenbrink, Valier Galy, Susan Q. Lang, Cameron Mcintyre, Robert G.M. Spencer, Ekaterina Bulygina, Zhaohui Aleck Wang, Katherine A. Guay

OES Faculty Publications

Sources of dissolved and particulate carbon to the Fraser River system vary significantly in space and time. Tributaries in the northern interior of the basin consistently deliver higher concentrations of dissolved organic carbon (DOC) to the main stem than other tributaries. Based on samples collected near the Fraser River mouth throughout 2013, the radiocarbon age of DOC exported from the Fraser River does not change significantly across seasons despite a spike in DOC concentration during the freshet, suggesting modulation of heterogeneous upstream chemical and isotopic signals during transit through the river basin. Dissolved inorganic carbon (DIC) concentrations are highest in …

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Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining Jan 2023

Authigenic Iron Is A Significant Component Of Oceanic Labile Particulate Iron Inventories, Laura E. Sofen, Olga A. Antipova, Kristen N. Buck, Salvatore Caprara, Lauren Chacho, Rodney J. Johnson, Gabriella Kim, Peter Morton, Daniel C. Ohnemus, Sara Rauschenberg, Peter N. Sedwick, Alessandro Tagliabue, Benjamin S. Twining

OES Faculty Publications

Particulate phases transport trace metals (TM) and thereby exert a major control on TM distribution in the ocean. Particulate TMs can be classified by their origin as lithogenic (crustal material), biogenic (cellular), or authigenic (formed in situ), but distinguishing these fractions analytically in field samples is a challenge often addressed using operational definitions and assumptions. These different phases require accurate characterization because they have distinct roles in the biogeochemical iron cycle. Particles collected from the upper 2,000 m of the northwest subtropical Atlantic Ocean over four seasonal cruises throughout 2019 were digested with a chemical leach to operationally distinguish labile …

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Synthesis, Densification, And Cation Inversion In High Entropy (Co,Cu,Mg,Ni,Zn)Al2o4 Spinel, Cole A. Corlett, Nina Obradovic, Jeremy Lee Watts, Eric W. Bohannan, William Fahrenholtz Jan 2023

Synthesis, Densification, And Cation Inversion In High Entropy (Co,Cu,Mg,Ni,Zn)Al2o4 Spinel, Cole A. Corlett, Nina Obradovic, Jeremy Lee Watts, Eric W. Bohannan, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

The synthesis, densification behavior, and crystallographic site occupancy were investigated for four different spinel-based ceramics, including a high-entropy spinel (Co0.2Cu0.2Mg0.2Ni0.2 Zn0.2)Al2O4. Each composition was reacted to form a single phase, but analysis of X-ray diffraction patterns revealed differences in cation site occupancy with the high-entropy spinel being nearly fully normal. Densification behavior was investigated and showed that fully dense ceramics could be produced by hot pressing at temperatures as low as 1375°C for all compositions. Vickers' hardness values were at least 10 GPa for all compositions. The …

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Efficient Text Bounding Box Identification Using Mask R-Cnn: Case Of Thai Documents, Phanthakan Kiatphaisansophon Jan 2023

Efficient Text Bounding Box Identification Using Mask R-Cnn: Case Of Thai Documents, Phanthakan Kiatphaisansophon

Chulalongkorn University Theses and Dissertations (Chula ETD)

Text detection is a fundamental task in computer vision, particularly for Optical Character Recognition (OCR) application. This research focuses on text detection part of the OCR. Our previous text detection model, CRAFT (Character-Region Awareness For Text detection) has shown promising outcomes in bounding box identification. Nevertheless, it encounters issues associated with post-processing and multiline text. The post-processing related to the necessity to reconfigure the model when new documents are introduced, resulting in inefficiencies and complexities. Also the CRAFT model tends to blend bounding boxes from consecutive lines, introducing errors and impacting the accuracy in the text recognition part of the …

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Laser-Induced Biochar For The Solid-Phase Extraction Of Organophosphorus Pesticides, Sherwin Hugo Tan Lu Jan 2023

Laser-Induced Biochar For The Solid-Phase Extraction Of Organophosphorus Pesticides, Sherwin Hugo Tan Lu

Chulalongkorn University Theses and Dissertations (Chula ETD)

Biochar is a carbon-rich material made from the combustion of biomass. It is a potential sustainable material for preconcentration sorbents, however conventional research uses energy-intensive pyrolysis methods to produce biochar sorbents. In this study, a more energy-efficient approach, using a laser irradiation process under ambient conditions, was studied to produce a biochar sorbent for the solid-phase extraction (SPE) of organophosphorous pesticides (OPPs) and analyzed by gas chromatography-mass spectrometry (GC-MS). Various biomass materials rich in lignin were tested to produce a biochar by a laser irradiation method. Cork sheet had the most consistent production of a laser-induced biochar and was selected …

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การเตรียมและลักษณะเฉพาะของแวกซ์เอสเทอร์จากกรดปาลมิติก, ณัฐกมล ดีมูลมั่ง Jan 2023

การเตรียมและลักษณะเฉพาะของแวกซ์เอสเทอร์จากกรดปาลมิติก, ณัฐกมล ดีมูลมั่ง

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มุ่งเน้นการสังเคราะห์แวกซ์ปาลมิติกผ่านปฏิกิริยารีดักชันและปฏิกิริยาเอสเทอริฟิเคชัน ปฏิกิริยารีดักชันเป็นการเปลี่ยนกรดปาลมิติกเป็นปาลมิติกแอลกอฮอล์ ตัวแปรของการศึกษานี้คือปริมาณของตัวเร่งปฏิกิริยาและเวลา ภาวะที่เหมาะสมในการทำปฏิกิริยาคือ ปริมาณของตัวเร่งปฏิกิริยา 2.66%w/w และเวลา 24 ชั่วโมง เนื่องจากผลิตภัณฑ์ที่ได้เป็นของผสมระหว่างผลิตภัณฑ์ปาลมิติกแอลกอฮอล์และกรดปาลมิติกส่วนเกิน จึงมีการสกัดแยกด้วยตัวทำละลาย เช่น เมทานอล เอทานอล ไอโซ-โพรพานอล เมทิลเอทิลคีโตน และไดเมทิลฟอร์มาไมด์ เพื่อแยกกรดปาลมิติกและผลิตภัณฑ์ปาลมิติกแอลกอฮอล์ จากนั้นทำปฏิกิริยาเอสเทอริฟิเคชันเพื่อสังเคราะห์แวกซ์เอสเทอร์ที่ได้จากกรดปาลมิติกและปาลมิติกแอลกอฮอล์ พบว่าแวกซ์ปาลมิติกสังเคราะห์จากปาลมิติกแอลกอฮอล์ได้สำเร็จ (อัตราส่วนระหว่าง CA/ตัวทำละลายเป็น 1:2) คือ W-CA-MeOH2, W-CA-EtOH2 และ W-CA-MEK2 ให้ร้อยละผลได้ของแวกซ์ปาลมิติกเอสเทอร์สูงที่ 48.1, 71.0 และ 56.7% ตามลำดับ สมบัติทางกายภาพและทางเคมีของแวกซ์ปาลมิติกศึกษาด้วยการวิเคราะห์ FTIR, XRD, NMR, DSC และ TGA แวกซ์ปาลมิติก W-CA-EtOH2 ซึ่งเป็นสารเคลือบกระดาษมีค่าความไม่ชอบน้ำยิ่งยวดสูงด้วยค่ามุมสัมผัส 161.4 องศา นอกจากนี้การเคลือบ W-CA-EtOH2 มีความต้านทานน้ำสูงโดยมีการดูดซึมน้ำต่ำที่ 0.43 ผลของการศึกษานี้บ่งบอกกระดาษที่เคลือบด้วยแวกซ์ปาลมิติกมีประสิทธิภาพความทนน้ำเพิ่มขึ้นเมื่อเทียบกับกระดาษที่ไม่คลือบ

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Tenvr: Matlab-Based Toolbox For Environmental Research, Aleksandar I. Goranov, Rachel L. Sleighter, Dobromir A. Yordanov, Patrick G. Hatcher Jan 2023

Tenvr: Matlab-Based Toolbox For Environmental Research, Aleksandar I. Goranov, Rachel L. Sleighter, Dobromir A. Yordanov, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

With the advancements in science and technology, datasets become larger and more multivariate, which warrants the need for programming tools for fast data processing and multivariate statistical analysis. Here, the MATLAB-based Toolbox for Environmental Research "TEnvR" (pronounced "ten-ver") is introduced. This novel toolbox includes 44 open-source codes for automated data analysis from a multitude of techniques, such as ultraviolet-visible, fluorescence, and nuclear magnetic resonance spectroscopies, as well as from ultrahigh resolution mass spectrometry. Provided are codes for processing data (e.g., spectral corrections, formula assignment), visualization of figures, calculation of metrics, multivariate statistics, and automated work-up of large datasets. TEnvR allows …

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Extracting High-Molecular Weight Dna From Cyanobacteria Using Promega's Wizard® Hmw Dna Extraction Kit With A Modified Protocol, Metis, Megan A. Hept, Lesley H. Greene Jan 2023

Extracting High-Molecular Weight Dna From Cyanobacteria Using Promega's Wizard® Hmw Dna Extraction Kit With A Modified Protocol, Metis, Megan A. Hept, Lesley H. Greene

Chemistry & Biochemistry Faculty Publications

Extraction of high molecular weight (HMW) DNA for long read sequencing with little to no fragmentation and high purity is difficult to acquire from cyanobacterial species. Here we describe a modified method of extraction using Promega's Wizard® HMW DNA Extraction Kit to acquire high molecular weight DNA from cyanobacterial species. The protocol used in the kit is the “3.D. Isolating HMW DNA from Gram-Positive and Gram-Negative Bacteria” protocol. During a key step in the protocol, the lingering remnants of the mucilage layer of the cyanobacterial species is removed, preventing it from sticking to the DNA pellet produced. This customized modification …

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Abiotic Stress Mitigation: A Case Study From 21 Trials Using A Natural Organic Matter Based Biostimulant Across Multiple Geographies, Rachel L. Sleighter, Terry Hanson, David Holden, Kristen M. Richards Jan 2023

Abiotic Stress Mitigation: A Case Study From 21 Trials Using A Natural Organic Matter Based Biostimulant Across Multiple Geographies, Rachel L. Sleighter, Terry Hanson, David Holden, Kristen M. Richards

Chemistry & Biochemistry Faculty Publications

Crop productivity and yields can be greatly diminished by abiotic stress events including drought, extreme temperatures, excess moisture, and saline irrigation water. Multiple stressors occurring simultaneously can further exacerbate the strain on plants. Various types of biostimulants have been shown to mitigate abiotic stress and here, the results of 21 trials on corn, wheat, soybean, and various high-value crops are discussed in the context of the abiotic stress that either occurred naturally or was experimentally induced. Treatments in these trials included stressed and non-stressed plants, as well as either an untreated control or grower standard fertilizer applications alone and in …

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Investigation Of Ch4 Adsorption And Activation On Modified Metalloporphyrin Graphene Sheets, Brianna Haase Jan 2023

Investigation Of Ch4 Adsorption And Activation On Modified Metalloporphyrin Graphene Sheets, Brianna Haase

Masters Theses

Finding a good catalyst for C-H bond breaking is important due to the rise of natural gas and crude oil emissions. From 2000-2006, CH4 emission concentrations stabilized, but in 2007, it sharply started increasing again. For example, atmospheric CH4 levels were 1886.37 ppb in July 2021 but this rose to 1904.52 ppb in just one year. Precious metal catalysts, such as Ir systems, have been used for C-H bond breaking, but are not sustainability ideal as they are costly to produce and have a significant carbon footprint. Because of this, less expensive 3d metal catalysts have risen in investigative …

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Using Superatomic Clusters And Charge Transfer Ligands To Control Electronic Characteristics Of Phosphorene Nanoribbons And Phosphorene Monolayer, Ryan Lambert Jan 2023

Using Superatomic Clusters And Charge Transfer Ligands To Control Electronic Characteristics Of Phosphorene Nanoribbons And Phosphorene Monolayer, Ryan Lambert

Theses and Dissertations

Phosphorene is a two-dimensional electron poor p-type semiconductor with high carrier mobility and great promise for applications in electronics and optoelectronics. As the main theme in this dissertation, the following work represents different investigations of various electronic properties associated with phosphorene. Most notable are the findings on charge transfer doping with metal-chalcogenide superatoms which displays novel control of the two most important properties of a semiconductor – the band gap energy and the nature of carriers. By tuning the width of the gap and p-/n-type character of conduction, we gain control over a material’s capacity to play a certain role …

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Alkyd Resins Produced From Bio-Based Resources For More Sustainable And Environmentally Friendly Coating Applications, Cemi̇l Dizman, Eli̇f Cerrahoğlu Kaçakgi̇l Jan 2023

Alkyd Resins Produced From Bio-Based Resources For More Sustainable And Environmentally Friendly Coating Applications, Cemi̇l Dizman, Eli̇f Cerrahoğlu Kaçakgi̇l

Turkish Journal of Chemistry

Recently, due to the depletion of natural resources and raising environmental and economic concerns regarding petroleum derivatives, the creation of novel ecologically friendly and sustainable materials made from bio-based and renewable resources is gaining popularity. Alkyd resins are synthetic resins in which both renewable (fatty acids, glycerol, oil, etc.) and nonrenewable (maleic anhydride, pentaerythritol, phthalic anhydride, etc.) raw materials are used in their production. Due to their superior performance (good aging, greater weather resistance and high heat resistance, outstanding gloss, etc.) over other resins, easy application, low cost, and varied use, in the coating and paint industries, they are commonly …

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Effect Of Okra Bast Fillers On Biodegradation Properties Of Poly(Vinyl Alcohol) Composites, Gazi Md Arifuzzaman Khan, Nazi̇re Deni̇z Yilmaz Jan 2023

Effect Of Okra Bast Fillers On Biodegradation Properties Of Poly(Vinyl Alcohol) Composites, Gazi Md Arifuzzaman Khan, Nazi̇re Deni̇z Yilmaz

Turkish Journal of Chemistry

This paper focuses on the effect of okra bast fillers on biodegradation of poly(vinyl alcohol) composites. Fibers were obtained from okra plant stems via biological degumming and subjected to different chemical treatments such as scouring, alkalizing, maleic anhydride treatment, and vinyl acetate grafting. The fibers were ground and PVA-okra bast filler composites were produced at 20 wt% fiber load via the solution casting method. The obtained composites were tested in terms of mechanical properties and exposed to biodegradation in soil. Effects of okra bast filler addition and chemical treatments on changes in mass, breaking strength, elasticity modulus, and breaking elongation …

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