Physical Sciences and Mathematics Commons^™

Optimizing And Evaluating Zinc Oxide Nanoparticles As A Matrix For Matrix-Assited Laser/ Desorption Ionization Mass Spectrometry For Small Molecule Detection In Rodent Brain Tissue, Juan Pablo Galindo

Electronic Thesis and Dissertation Repository

Matrix-assisted laser/desorption ionization (MALDI) is the preferred method for mass spectrometry imaging (MSI) due to its high spatial resolution. Detecting small molecules like γ-aminobutyric acid (GABA) and glutamate, which are the main inhibitory and excitatory neurotransmitters respectively, proves challenging as their low masses conflict with background signals from most matrices.

This work optimizes zinc oxide nanoparticles (ZnO NP) as a matrix, focusing on GABA and Glutamate detection. Its absence of background signal makes ZnO suitable for small molecule detection. Its shortcomings, especially batch-to-batch variability, were mitigated through filtration and sonication before deposition, achieving high-resolution imaging of rat brain tissue sections. …

Asymmetric Electrode-Electrolyte Interfaces For High-Performance Rechargeable Lithium-Sulfur Batteries, Jia Chou, Ya-Hui Wang, Wen-Peng Wang, Sen Xin, Yu-Guo Guo

Journal of Electrochemistry

With a high cell-level specific energy and a low cost, lithium-sulfur (Li-S) battery has been intensively studied as one of the most promising candidates for competing the next-generation energy storage campaign. Currently, the practical use of Li-S battery is hindered by the rapidly declined storage performance during battery operation, as caused by irreversible loss of electroactive sulfide species at the cathode, dendrite formation at the anode and parasitic reactions at the electrode-electrolyte interface due to unfavorable cathode-anode crosstalk. In this perspective, we propose to stabilize the Li-S electrochemistry, and improve the storage performance of battery by designing asymmetric electrode-electrolyte interfaces …

Three-Dimensional Two-Phase Cfd Simulation Of Alkaline Electrolyzers, Ling-Yu Gao, Lin Yang, Chen-Hui Wang, Gui-Xuan Shan, Xin-Yi Huo, Meng-Fei Zhang, Wei Li, Jin-Li Zhang

Journal of Electrochemistry

The structural and operation parameters of the electrolyzer play important roles in the efficiency of alkaline water electrolysis. In this article, a three-dimensional numerical model coupled with the electric field and the Euler-Eulerian k-ε turbulence flow field was first established to simulate accurately the performance of alkaline electrolyzers, based on a compact assembly structure of the industrial alkaline water electrolyzers, especially at current densities higher than 5000 A·m^–2. The simulation results are compared with the experimental data to verify the accuracy of the model. Suitable operating conditions for concentration, flow rate and the optimal design method of the …

Dependence Of Heat Transfer Model On The Structure Of Electrically Coil-Heated Microelectrodes, Ju Li, Sen Yang, Jian-Jun Sun

Journal of Electrochemistry

Electrically heated microelectrodes have gained much attention in electroanalytical chemistry in recent years. It has been shown that the promotion of mass transport and reaction kinetics at high-temperatures often results in increased current signals. However, there is no study about the heat transfer inner the microelectrodes which is necessary for the design and operation for microsensors. This report introduces a finite element software (COMSOL) to analyze the factors that influence the surface temperature (T_s), which is crucial for the heating ability of micro-disk electrodes with coils. Distances between the electrode surface and the bottom of the heated copper …

Hydrophobicity Optimization Of Cathode Catalyst Layer For Proton Exchange Membrane Fuel Cell, Hao-Jie Chen, Mei-Hua Tang, Sheng-Li Chen

Journal of Electrochemistry

Hydrophobicity of the cathode catalyst layers (CCLs) crucially determines the performance of proton exchange membrane fuel cells (PEMFCs) by affecting the transports of oxygen and liquid water. In this regard, polytetrafluoroethylene (PTFE) is usually used as a hydrophobic additive to facilitate the oxygen and water transports in CCLs. So far, there remains lacking systematic effort to optimize the addition methods of PTFE in CCLs and the mechanisms behind. In this work, the effects of the approaches for PTFE addition and the distribution of PTFE on the mass transport of oxygen and the proton conduction in CCLs were studied by using …

Molecularly Imprinted Electrochemical Sensor Based On Poly (O-Phenylenediamine) For Sensitive Detection Of Oxycodone In Water, Pranaya Charkravarthula, Amos Mugweru

College of Science & Mathematics Departmental Research

This work was aimed at the development of a sensitive electrochemical detection method for oxycodone in water. Molecularly imprinted electrodes were formed by electro-polymerization process using o-phenylenediamine as a monomer. The electro-polymerization was performed on glassy carbon electrodes in the presence of oxycodone before the extraction of entrapped oxycodone molecules. Various electrochemical techniques were employed to monitor the polymerization and response of the fabricated electrodes toward oxycodone. These techniques included cyclic voltammetry (CV), square wave voltammetry (SWV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The oxycodone concentration was determined using SWV by measuring the change in the oxidation …

Comparative Study Of Guanidine-, Acetamidine- And Urea-Based Chloroaluminate Electrolytes For An Aluminum Battery, Iwan Sumarlan, Anand Kunverji, Anthony J Lucio, A Robert Hillman, Karl S Ryder

Student and Faculty Publications

Aluminum-based batteries are a promising alternative to lithium-ion as they are considered to be low-cost and more friendly to the environment. In addition, aluminum is abundant and evenly distributed across the globe. Many studies and Al battery prototypes use imidazolium chloroaluminate electrolytes because of their good rheological and electrochemical performance. However, these electrolytes are very expensive, and so cost is a barrier to industrial scale-up. A urea-based electrolyte, AlCl3:Urea, has been proposed as an alternative, but its performance is relatively poor because of its high viscosity and low conductivity. This type of electrolyte has become known as an ionic liquid …

Developing New Strategies Towards The Fabrication Of Flexible, Organic Electronics, Daniella Skaf

Electronic Theses and Dissertations

An investigation into the use of greener dielectric and substrate materials, specifically shellac and paper, was done through the development of paper-based organic thin film transistors. Shellac and paper both hold advantageous properties that were explored in Chapter III, through the optimization in the fabrication of the devices and an evaluation of the electrical properties of these newly developed organic transistors. Different designs were explored using two common DPP-based polymers, P(DPP-T) and P(DPP-TVT), as the active materials, with Design #2 (bottom-gate top-contact) proving to be the best performing device according to the on/off ratio, charge mobilities and threshold voltage. Shellac …

Structural Control Of Metallothionein Metallation And Oxidation, Natalie C. Korkola

Electronic Thesis and Dissertation Repository

Metallothioneins (MT) are a family of cysteine-rich metal-binding intrinsically disordered proteins that are ubiquitous across life. The proposed functions of MTs are to maintain Zn(II) homeostasis, participate in heavy metal detoxification, and protect against oxidative stress by binding to a variety of metals in a range of stoichiometries. However, due to their disordered nature and ability to form multiple metallated species, these diverse structures are not well characterized. Electrospray ionization mass spectrometry (ESI-MS) is a technique that allows quantification of heterogeneous metallation states through analysis of the speciation distributions. In this thesis, ESI-MS in combination with other spectroscopic techniques is …

Fundamental Study Of Ionic Liquid Physicochemical Effects On Thermal Stability Of Model Biological Macromolecules, Austin Keith Clark

Theses and Dissertations

Ionic Liquids (ILs) are substances with a unique physical attribute compared to that of solid ionic salts. At room temperature, ILs are molten salts that have a variety of physical effects that can play a role in their impact on other molecules, as solvents or solutes. They can play the role of the solvent in a variety of applications, from biofuels to organic catalysis or as excipients in pharmaceutical formulations. These ILs have a desirable use as solvents due to their ability to be tunable substances. Changing the cation or anion of the IL causes a change in its physical …

Synthesis And Evaluation Of Novel Nucleotide Prodrugs Against Sars-Cov-2, Mohammed Attaelmanan

Electronic Thesis and Dissertation Repository

Positive sense RNA (ribonucleic acid) viruses (+ssRNA) are the known causative agents of diseases throughout history. These includes Hepatitis C Virus (HCV), SARS-CoV, and recently SARS-CoV-2. RNA dependent RNA polymerase (RdRp), a critical enzyme in the life cycle of the virus, can be targeted by using nucleotide antivirals thus causing inhibition. Novel ribonucleotides antiviral agents that possess nucleobase modifications and a 5′-phosphoramidate prodrug moiety, referred to as a ProTide, have been synthesized. The ribonucleoside analogues were constructed by CuI catalyzed azide-alkyne cycloaddition chemistry (CuAAC), also referred to as ‘click’ chemistry. The synthetic route utilized 5-ethynylpyrimidines and azidoribofuranoses as CuI ‘click’ …

Phosphorus And Its Role In Chemical Evolution, Asbel Gonzalez

PANDION: The Osprey Journal of Research and Ideas

Phosphorus is a minor element with a cosmic abundance of about 105.5 atoms per 1012 H atoms (Boudreaux, n.d.). Phosphorus was depleted as a volatile throughout the developing solar system, and as a result, volatile forms of phosphorus would have been minimal, even in the colder regions of the solar nebula. Despite its low abundance, phosphorus minerals play key roles in planetary petrology, including through the formation of phosphate minerals that trapped volatiles and rare Earth elements, and in the formation of metal phosphides that may have served as nucleation sites for kamacite and taenite crystal growth in minor planet …

Antibacterial Testing On Silver/Zinc Oxide Nanoparticles/Organoclay Reinforced Chitosan Biocomposites, Lisna Junaeni Muiz, Ariadne Lakshmidevi Juwono, Zulkarnaen Paputungan, Yuni Krisyuningsih Krisnandi

Makara Journal of Science

Herein, bionanocomposites of chitosan (CS)/silver nanoparticle/organoclay/zinc oxide nanoparticle (CS/Ag/OC/ZnO) were prepared for antibacterial food packaging. This study examines the time variation in the AgNP synthesis method by comparing local (74˗85% deacetylated) and commercial chitosan (75%˗85% deacetylated) as a reducing and capping agent and seeks to reconstruct the optimum ratio formulations of AgNPs and ZnONPs in bionanocomposites for food packaging. The results reveal that the synthesis of AgNPs was successfully carried out using a local chitosan solution as a reducing and capping agent. The CS/Ag/OC/ZnO films exhibit structural, mechanical, and optical properties suitable for food packaging and antibacterial activity on Staphylococcus …

Synthesis, Characterization, Antibacterial Activity, And Potential Water Filter Application Of Copper Oxide/Zeolite Composite, Elfa Aida Kamila, Zaenal Abidin, Irma Isnafia Arief, Trivadila Trivadila

Makara Journal of Science

Detection of E. coli bacteria in water samples can indicate the presence of other bacterial contamination in feces. Bacterial contamination can be treated with antibiotics, but excessive use of antibiotics leads to the emergence of multiresistant bacteria. Therefore, alternative antibacterial agents must be explored. Copper ion/zeolite composite has been widely studied as an antibacterial agent. However, the released copper ions accumulate in water and are toxic to humans; this can be prevented by converting copper ions into copper oxides (CuO and Cu₂O). In this study, copper oxide/zeolite composite is synthesized and characterized using the heating method, followed by …

Synergistic Effect Of Nanoclay And Barium Sulfate Fillers On The Corrosion Resistance Of Polyester Powder Coatings, Jinbao Huang, Marshall Shuai Yang, Chengqian Xian, James Joseph Noel, Yolanda S. Hedberg, Jian Chen, Ubong Eduok, Ivan Barker, Jeffrey Daniel Henderson, Haiping Zhang, Liqin Wang, Hui Zhang, Jesse Zhu

Chemistry Publications

No abstract provided.

Exploring Students’ Epistemological Understanding Of Atomic Structure Models, Claire V. Ward, Morgan Balabanoff

The Cardinal Edge

Developing a robust understanding of atomic structure and the nature of matter is foundational across chemistry and STEM courses. The development of this concept is challenging because it relies on models to illustrate something not directly observable. Scientific models are important tools used to explain phenomena, particularly phenomena that are not directly observable. In general chemistry, students are typically asked to consider four different models: (1) the particle model, (2) the nuclear model, (3) the Bohr model, and (4) the Quantum model. Each depiction has its own advantages and limitations, where instructors introduce each model to explain specific parts of …

Characterization And Electrolysis Of Zn And Cu 2,6-Diacetylpyridine Bis(2-Hydrazinopyridine), Bailee G. Duff, Christine Phipps, Craig Grapperhaus

The Cardinal Edge

With increasing demands for fuel and concerns over climate change, the search for sustainable energy sources is ever growing. Hydrogen is a potential solution to these issues, as it is clean, recyclable, and efficient. However, hydrogen must be generated, unlike other fuel sources that are naturally ready for use. The most sustainable method for hydrogen production involves water electrolysis, as no pollution is generated. The water splitting process contains a cathodic hydrogen evolution reaction (HER) and an anodic oxygen evolution reaction (OER). These reactions require a catalyst to overcome the kinetic barrier present and meet the high voltage requirements for …

Exploring Retrieval Difficulties And Self-Confidence In An Assessment Of General Chemistry Students, Karen Julian, Morgan Balabanoff

The Cardinal Edge

Developing self-assessment skills is an important aspect of learning. Framed by assessment developed for the year-long sequence of general chemistry, students were asked to rate their ability to answer conceptual questions. Using cognitive interviews, this study revealed that people rely on a range of characteristics other than content knowledge to assess their confidence, including doubt, retrieval difficulty, and test-taking methods. These findings imply that more explicit instruction may be required to encourage correct self-assessment. Students can develop their metacognitive skills and calibrate their perceived ability by completing examinations meant to emphasize content knowledge gaps.

Eggshell-Alginate Composites (Eacs) As Eco-Friendly Adsorbents For Rhodamine B Uptake From Aqueous Solutions, Rusnadi Rusnadi, Mar’Atus Sholihah, Nurrahmi Handayani, Muhammad Ali Zulfikar

Karbala International Journal of Modern Science

The contamination of wastewater by Rhodamine B (RhB) poses a significant environmental concern due to its negative impacts on aesthetics, ecosystems, and human well-being. This study successfully synthesized eco-friendly egg-shell-alginate composites (EACs) as adsorbents by combining alginate solution, eggshell powder, and a 2% CaCl2 solu-tion. Characterization techniques including FTIR, SEM, TGA, and SAA were employed to analyze the EACs. FTIR analysis revealed characteristic absorption peaks corresponding to -OH groups, C=O groups, C-O groups, and the pres-ence of CO32-. The structural analysis confirmed the physical mixture of functional groups from eggshells and alginate, resulting in a homogeneous EACs mixture. TGA analysis …

Synthesizing Of Alginate Coated-Silver Nanoparticles Core-Shell For Detecting Of S-Naproxen Enantiomer In Pharmaceutical Formulation, Abdolrasol Barazandeh, Ghasem Najafpour-Darz, Afshar Alihossein, Sohrab Kazemi

Karbala International Journal of Modern Science

Core-shell nanoparticles were used in a unique direct UV-Vis spectrophotometric technique to detect the S-naproxen enantiomer. Silver nanoparticles (Ag NPs) covered with sodium alginate (Alg) shell, a naturally occurring biopolymer, made the core of the nanostructure. To name a few, TEM, FESEM, UV-Visible, DLS, ZP, AFM, XRD, EDX and FT-IR are among the analytical methods used to analyze the creation of the core-shell structure. Based on obtained results, spherical Ag@ Alg NPs with an average size of 27.4 nm (DTEM), hydrolytic size of 46 nm (DDLS) and surface charge of -60.9 mV were successfully synthesized. The effect of various reaction …

Thermodynamic And Kinetic Modeling Of Electrocatalytic Reactions Using A First-Principles Approach, M. Vasanthapandiyan, Shagun Singh, Fernanda Bononi, Oliviero Andreussi, Naiwrit Karmodak

Chemistry and Biochemistry Faculty Publications and Presentations

The computational modeling of electrochemical interfaces and their applications in electrocatalysis has attracted great attention in recent years. While tremendous progress has been made in this area, however, the accurate atomistic descriptions at the electrode/electrolyte interfaces remain a great challenge. The Computational Hydrogen Electrode (CHE) method and continuum modeling of the solvent and electrolyte interactions form the basis for most of these methodological developments. Several posterior corrections have been added to the CHE method to improve its accuracy and widen its applications. The most recently developed grand canonical potential approaches with the embedded diffuse layer models have shown considerable improvement …

Investigation Of The Thermodynamics For The Removal Of As(Iii) And As(V) From Water Using Synthesized Zno Nanoparticles And The Effects Of Ph, Temperature, And Time, Helia Magali Morales, Grecia Torreblanca, Arnulfo Mar, Mataz Alcoutlabi, Thomas Eubanks, Erik Plata, Jason Parsons

Chemistry Faculty Publications and Presentations

In the present study, the removal of both As(III) and As(V) from aqueous solutions using synthesized ZnO nanomaterials was achieved. The ZnO nanomaterial was synthesized using a precipitation technique and characterized using XRD, SEM, and Raman spectroscopy. XRD confirmed the ZnO nanoparticles were present in the hexagonal wurtzite structure. SEM of the particles showed they were aggregates of triangular and spherical particles. The average nanoparticle size was determined to be 62.03 ± 4.06 nm using Scherrer’s analysis of the three largest diffraction peaks. Raman spectroscopy of the ZnO nanoparticles showed only ZnO peaks, whereas the after-reaction samples indicated that As(V) …

Ambient Processed Rgo/Ti3cntx Mxene Thin Film With High Oxidation Stability, Photosensitivity, And Self-Cleaning Potential, Muhammad Abiyyu Kenichi Purbayanto, Dominika Bury, Madhurya Chandel, Zhila Dehghan Shahrak, Vadym Mochalin, Anna Wójcik, Dorota Moszczyńska, Anita Wojciechowska, Anika Tabassum, Michael Naguib, Agnieszka Maria Jastrzębska

Chemistry Faculty Research & Creative Works

Solution-Based Processing Offers Advantages for Producing Thin Films Due to Scalability, Low Cost, Simplicity, and Benignity to the Environment. Here, We Develop Conductive and Photoactivated Self-Cleaning Reduced Graphene Oxide (RGO)/Ti₃CNT_x MXene Thin Films Via Spin Coating under Ambient Conditions. the Addition of a Thin RGO Layer on Top of Ti₃CNT_x Resulted in Up to 45-Fold Improvement in the Environmental Stability of the Film Compared to the Bare Ti₃CNT_x Film. the Optimized RGO/Ti₃CNT_x Thin Film Exhibits an Optical Transmittance of 74% in the Visible Region of the Spectrum and …

Molecular And Physical Composition Of Tar Balls In Wildfire Smoke: An Investigation With Complementary Ionisation Methods And 15-Tesla Ft-Icr Mass Spectrometry, Amna Ijaz, William Kew, Zezhen Cheng, Susan Mathai, Nurun Nahar Lata, Libor Kovarik, Simeon Schum, Swarup China, Lynn Mazzoleni

Michigan Tech Publications, Part 2

Tar balls (TBs) are a major carbonaceous product of wildfires and other biomass-burning events that often exceed soot or other elemental forms of carbon in number and mass. Being a recalcitrant fraction of organic carbon, TBs are capable of long-range atmospheric transport, and thus, exert influence not only in the vicinity of wildfires but also in remote regions. Here, we characterised ambient atmospheric aerosol samples with varying TB number fractions collected downwind of Pacific Northwest wildfires using a 15-Tesla Fourier transform-ion cyclotron resonance mass spectrometer (15-T FT-ICR MS). Relative to non-TB aerosol, we found 2006 and 851 molecular formulae exclusively …

Designing Polymers For Cartilage Uptake: Effects Of Architecture And Molar Mass., Jue Gong, Jordan Nhan, Jean-Philippe St-Pierre, Elizabeth R Gillies

Chemistry Publications

Osteoarthritis (OA) is a progressive disease, involving the progressive breakdown of cartilage, as well as changes to the synovium, and bone. There are currently no disease-modifying treatments available clinically. An increasing understanding of the disease pathophysiology is leading to new potential therapeutics, but improved approaches are needed to deliver these drugs, particularly to cartilage tissue, which is avascular and contains a dense matrix of collagens and negatively charged aggrecan proteoglycans. Cationic delivery vehicles have been shown to effectively penetrate cartilage, but these studies have thus far largely focused on proteins or nanoparticles, and the effects of macromolecular architectures have not …

Protein Stability In Solution And In The Gas Phase., Yousef Haidar

Electronic Thesis and Dissertation Repository

Electrospray Ionization mass spectrometry (ESI-MS) is widely used for probing proteins, yet many aspects of this technique remain elusive. Using MS, ion mobility spectrometry (IMS), and circular dichroism (CD) spectroscopy, this thesis sheds light on the stability differences of proteins in the gas phase and solution. After a general introduction (Chapter 1), Chapter 2 scrutinizes some aspects of native ESI. Our data highlight the significance of cone voltage in maintaining a native-like fold and show the advantage of using NH₄Ac in protein experiments. Chapter 3 focuses on hydrogen/deuterium exchange (HDX)-MS. Several studies have reported that D₂O …

Approaches To Assessing Nutrient Coupling In Open Ocean Datasets, James M. Moore, Claire P. Till

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

Nutrient coupling describes a process where the biogeochemical cycles of two elements are linked by being incorporated similarly into biomass. This paper uses data from the GEOTRACES GP16 cruise (Eastern Pacific Zonal Transect) to investigate the relationship between certain macronutrients generally coupled to trace elements in terms of their oceanic distributions with the notable exception of in an oxygen minimum zone: cadmium-phosphate and zinc-silicate. There are many methods applied to oceanographic data to correlate analyte concentrations; while they are often presented independently in literature, here we attempt to use them in conjunction for a more thorough interpretation. By compiling 1) …

Development Of Single-Crystalline And 3d-Printable Porous Organic Materials, Mingshi Zhang

Dartmouth College Ph.D Dissertations

Porous organic materials with designable structures, large surface areas, low densities, and unique electronic and optical properties have found widespread applications in adsorption, separation, energy storage, and catalysis. However, the majority of organic porous materials are synthesized as fluffy powders, which poses two fundamental challenges for them. Firstly, they lack a single-crystal structure at the microscopic scale, making it difficult to study the specific pore size, shape, and potential substrate binding sites at the atomic level and further establish the structure-property relationship. Secondly, they lack the general processing method and macroscopic shape design, making it difficult to manufacture suitable components …

Microplastics In Water, Their Effects On The Aquatic Ecosystem And Human Public Health, And The Proposed Solutions, Mohanad Abouserie

The Undergraduate Research Journal

We could be swallowing a credit card's weight in plastic every week. Microplastic water pollution is becoming a threat to both humans and aquatic creatures. In this research, microplastic water contamination is discussed, and divergent solutions are proposed. This paper attempts to investigate the causes and effects of such pollution and analyze the current solutions for this issue. The adopted research method is secondary research, where several studies are explored and analyzed. This study explains numerous causes for this issue like cosmetics, cleaning products, factories, and sewage. Consequently, this contamination can negatively impact the organs and metabolisms of the living …

From Random To Rational: Improving Enzyme Design Through Electric Fields, Second Coordination Sphere Interactions, And Conformational Dynamics, Shobhit S. Chaturvedi, Daniel Bím, Christo Christov, Anastassia N. Alexandrova

Michigan Tech Publications, Part 2

Enzymes are versatile and efficient biological catalysts that drive numerous cellular processes, motivating the development of enzyme design approaches to tailor catalysts for diverse applications. In this perspective, we investigate the unique properties of natural, evolved, and designed enzymes, recognizing their strengths and shortcomings. We highlight the challenges and limitations of current enzyme design protocols, with a particular focus on their limited consideration of long-range electrostatic and dynamic effects. We then delve deeper into the impact of the protein environment on enzyme catalysis and explore the roles of preorganized electric fields, second coordination sphere interactions, and protein dynamics for enzyme …