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Full-Text Articles in Physical Sciences and Mathematics

The Impact Of Project-Based Learning On Students In High School Chemistry In Rural Maine, Brianna Degone Dec 2021

The Impact Of Project-Based Learning On Students In High School Chemistry In Rural Maine, Brianna Degone

Electronic Theses and Dissertations

Project-based learning (PBL) is an instructional strategy that is promoted throughout education for its use of active learning and ability to connect to real-world applications. Studies have been conducted on PBL ranging from early elementary grades through graduate courses, however little research considers the effectiveness of PBL at the secondary science level. This thesis considers the use of PBL and describes the implementation of a PBL unit in a rural Maine 11th grade chemistry classroom. The thesis aims to better understand the impact PBL has on students’ content learning and additional skills acquired through the PBL learning process. Along with …


Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally Dec 2021

Gradient Generating Microfluidic Coculture System For Disease Modeling And Neural Development, Phaneendra Chennampally

Electronic Theses and Dissertations

Cellular microenvironment or cell niche plays an important role in developmental biology and disease pathophysiology. Physical or chemical signals in microenvironment drive the cellular activity. These signaling molecules are generated from the surrounding cells/tissues as part of intercellular communication; a fundamental property of a cell. Dynamic profile of these signaling molecules in the microenvironment plays a pivotal role in transfer of molecular information from cell to cell in disease proliferation or fate determination. Recapitulating these signaling cues in an in vitro study is difficult to achieve using standard cell culture techniques. However microfluidic systems are capable of addressing these issues, …


Asymmetric Synthesis Of Phosphate Mimics: From Chemistry To Biotechnology, Ahmed Numan Aug 2021

Asymmetric Synthesis Of Phosphate Mimics: From Chemistry To Biotechnology, Ahmed Numan

Electronic Theses and Dissertations

Oligonucleotide based therapeutics have been pursued in the clinic for the treatment of many disease indications. However, unmodified oligonucleotides are polyanionic macromolecules with poor drug-like properties. Modifications of the phosphodiester backbone provide resistance to nucleases in vivo, making them more efficacious than unmodified nucleotides. However, these backbone modifications have added the structural complexity of a stereogenic phosphorus center. Stereochemically pure isomers exhibit differential efficiency dependent on its enantiopurity. The catalytic, stereocontrolled synthesis of a phosphorus-stereogenic center is challenging, and traditionally, depends on a resolution or use of stochiometric auxiliaries. Herein, asymmetric nucleophilic catalysis has been investigated to provide enantio-enriched phosphonates …


To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand Aug 2021

To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand

Electronic Theses and Dissertations

Ever since the eighteenth century, experts have tried to tell farmers how to farm. The agricultural enlightenment in Europe marked the beginning of a long arc of new experts aiming to change agricultural knowledge and practice. This dissertation analyzes the pivotal period in the late nineteenth and early twentieth century in Germany and the United States when scientists, improvers, and market agents began to develop comprehensive ways to communicate agricultural innovation to farmers. In a functional approach to analyzing the negotiation of agricultural knowledge through its communication in things, words, and practices, this dissertation argues that the process of change …


Development Of Nanostructured Titania-Incorporated Photocatalysts For Environmental Applications, Sudheera B. Yaparatne Jul 2021

Development Of Nanostructured Titania-Incorporated Photocatalysts For Environmental Applications, Sudheera B. Yaparatne

Electronic Theses and Dissertations

Ultraviolet (UV) radiation application in water and wastewater treatment has become a common approach for inactivation of protozoa and other pathogenic microorganisms. However, degradation of most organic compounds, such as taste and odor products prevalent in surface waters, has not been proven effective with direct UV photolysis. Advanced oxidation processes (AOPs) that involve efficient photocatalysts like TiO2 show an advantage over direct UV photolysis providing fast reaction rates and non-selective oxidation of contaminants. However, the real-world application of TiO2 in water and wastewater treatment is limited due to difficulties in separating the suspended nanosized particles following treatment, the …


Development Of Methods For Determining Water Content In Oil Using Infrared Spectroscopy, Sfoog Hamad Saleh May 2021

Development Of Methods For Determining Water Content In Oil Using Infrared Spectroscopy, Sfoog Hamad Saleh

Electronic Theses and Dissertations

Karl Fischer Titration (KFT) is the “gold standard” method for measuring the amount of water in oils. KFT is a laborious and time-consuming method that requires expensive and hazardous chemicals which has provided the impetus to develop alternative methods. In this thesis, we investigated three approaches for determining water content in oils that are based on the use of infrared spectroscopy. In the first approach, we developed a simple method for measuring water concentrations from 1 to 5000 ppm in various types of oil that uses no hazardous, and expensive, chemical reagents or matrix specific calibrations. This approach involves capturing …


Synthesis And Photophysical Studies Of Nitrogen Heterocycles Containing Benzothiazines, Benzothiazoles, Indoles And Quinolines, Ealin N. Patel May 2021

Synthesis And Photophysical Studies Of Nitrogen Heterocycles Containing Benzothiazines, Benzothiazoles, Indoles And Quinolines, Ealin N. Patel

Electronic Theses and Dissertations

Nitrogen heterocycles such as quinolines, benzothiazines, benzothiazoles, and indoles are widely found in nature and these compounds have significance in organic and medicinal chemistry, biochemistry as well as materials science. Monomeric units of eumelanin (brominated 5,6- dimethoxyindolecarboxylate derivatives) were synthesized and regioselectively functionalized to form three monobrominated, three dibrominated, and a tribrominated variant using thermally induced nitrene insertions. After deprotection, three monobrominated 5,6-dihydroxyindole carboxylate (DHICA) derivatives were synthesized, and their UV-Vis absorbance was compared to DHICA. Bominated DHICA derivatives showed similar λmax as DHICA (~330 nm) but did not show aerial oxidation as evident by absence of chromophore absorbance at …