Chemistry Commons^™

Preparation And Characterisation Of Heat Treated Oil Palm-Empty Fruit Bunch/High Density Polyethylene Composites, Nordin Nur Afifah

Student Works (2020-2029)

Natural fibre composites (NFCs) are composite materials, in which the reinforcing fibres are derived from renewable and carbon dioxide neutral resources such as wood or plants. NFC can be made by replacing synthetic fibres with various types of natural fibres. Oil palm empty fruit bunch (OPEFB) fibre and oil palm mesocarp fibre are two important types of fibrous materials left in the palm-oil industry. In this study, EFB will be used as a reinforcement to the high-density polyethylene (HDPE). EFB was heat-treated at 180°C using vacuum oven for one hour, extrusion compounded with HDPE at 10%, 20% and 30% weight …

Synthesis, Structure Elucidation And Selected Biological Activities Of Ag(I) And Au(I) Complexes Constructed From Thiosemicarbazone And Phosphine Ligands, Syahrina Nur ‘Ain Abdul Halim

Student Works (2020-2029)

New Ag(I) and Au(I) mixed ligand complexes were synthesised using thiosemicarbazone and phosphine in search of a new biologically active compounds. CHN elemental analysis, powder X-ray diffraction (PXRD), single crystal X-ray diffraction as well as several spectroscopic techniques such as FT-IR, Energy-dispersive X-ray (EDX), 1H, 13C, and 31P{1H} NMR were performed to elucidate the structure of these complexes. Elemental analysis suggested that the stoichiometry of the complexes formed by the reaction of Ag nitrate with thiosemicarbazone in the presence of phosphine was indeed 1:2:1 molar ratio, while for the Au to be in 1:1:1 molar ratio. The Ag and Au …

Pressure Driven Desalination Utilizing Nanomaterials, Fangyou Xie

Master's Theses

Nanomaterials such as graphene oxide and carbon nanotubes, have demonstrated excellent properties for membrane desalination, including decrease of maintenance, increase of flux rate, simple solution casting, and impressive chemical inertness. Here, two projects are studied to investigate nanocarbon based membrane desalination. The first project is to prepare hybrid membranes with amyloid fibrils intercalated with graphene oxide sheets. The addition of protein amyloid fibrils expands the interlayer spacing between graphene oxide nanosheets and introduces additional functional groups in the diffusion pathways, resulting in increase of flux rate and rejection rate for the organic dyes. Amyloid fibrils also provide structural assistance to …

Rheological Studies Of Fully-Formulated Coatings Thickened With Heur: Effects Of Surfactants, Brandon M. Bonilla

Master's Theses

Rheology modifiers such as hydrophobically-modified ethoxylated urethane (HEUR)thickeners are included in waterborne latex coatings to optimize shear-rate dependent viscosity and other rheological properties. While these HEUR polymers are commonly used in industry, the complex chemical interactions that contribute to rheological properties are still not completely understood. Prior work in this area has focused on understanding latex-HEUR and latex-surfactant-HEUR interactions that affect rheological properties. Additionally, studies have been previously conducted to understand the relaxation mechanisms of complex interactions present in HEUR-thickened waterborne latex coatings under various dynamic conditions. The objective of this work is to extend the experimental work to fully-formulated …

I. Selective Chlorination And Fluorination Of Quinols Ii. Synthetic Study Of Strongylophorine-26, Sihan Li

Dissertations, Theses, and Capstone Projects

Organic compounds containing halogen are an important and useful class of intermediates that can be converted to other functionalities. This thesis describes our strategy in selective chlorination and fluorination of quinols to offer the corresponding aromatic structures. Quinols, or cyclohexadienones, as oxidized derivatives of phenols, have their remarkable chemical reactivities, including additions to enone, enolate alkylations, aldol reactions, cycloadditions, and rearrangements. Dienone-phenol rearrangement provides the asymmetric route since the stereocenters located in the six-membered ring of various cyclohexadienone were widely using in building larger chiral arrays for many total syntheses

Chapter one of this thesis discusses our new selective nucleophilic …

Capsaicin Is A Negative Allosteric Modulator Of The 5-Ht3 Receptor, Eslam El Nebrisi, Tatiana Prytkova, Dietrich Ernst Lorke, Luke Howarth, Asma Hassan Alzaabi, Keun-Hang Susan Yang, Frank Christopher Howarth, Murat Oz

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this study, effects of capsaicin, an active ingredient of the capsicum plant, were investigated on human 5-hydroxytryptamine type 3 (5-HT₃) receptors. Capsaicin reversibly inhibited serotonin (5-HT)-induced currents recorded by two-electrode voltage clamp method in Xenopus oocytes. The inhibition was time- and concentration-dependent with an IC₅₀ = 62 μM. The effect of capsaicin was not altered in the presence of capsazepine, and by intracellular BAPTA injections or trans-membrane potential changes. In radio-ligand binding studies, capsaicin did not change the specific binding of the 5-HT₃ antagonist [³H]GR65630, indicating that it is a noncompetitive inhibitor of …

Detection Of Melamine Based On The Suppressed Anodic Response Of Uric Acid By A Au-Ag Nanoparticles Modified Glassy Carbon Electrode, Yu-Hui Peng, Tsunghsueh Wu, Yang-Wei Lin

Journal of Food and Drug Analysis

We demonstrated a sensitive electrochemical method for the determination of non-electroactive melamine (Mel) using a modified glassy carbon electrode (GCE), with uric acid (UA) as the signal reporter. To increase the anodic response of UA, GCE was coated with Au–Ag nanoparticles and a Nafion thin film (Au–Ag/Nafion/GCE). The sensing mechanism was based on the competitive adsorption behavior of Mel on the Au–Ag/Nafion/GCE, which reduces the electroactive surface area of nanoparticles and thus hinders anodic response of UA. Under optimal conditions and the use of an analytical method of differential pulse voltammetry, this modified electrode detected Mel concentrations ranging from 2.5 …

Spatiotemporal Patterns Of Polychlorinated Dibenzo-P-Dioxins And Dibenzofurans And Dioxin-Like Polychlorinated Biphenyls In Foodstuffs In Air Quality Regions In Taiwan, Ching-Chang Lee, Wei-Hsiang Chang, Hsin-Tang Lin, Jung-Wei Chang

Journal of Food and Drug Analysis

High-fat food intake is the main source of dioxin-like compounds for humans, such as consumption of meat, dairy and eggs, and seafood products. Fruits, vegetables, and cereals have relatively low levels of dioxin-like compounds, but because of high consumption they also contribute to the food-borne intake. It is necessary to clarify dietary dioxin exposure affected by different food contamination levels and dietary habits among different geographic areas. We aimed to evaluate chronic dietary PCDD/Fs and DL-PCBs exposure in 725 individual foods in 14 categories in 6 Taiwan air quality regions (AQRs) and a total of 2,441 foods from 2004 and …

Recent Progress In Bifunctional Catalysts For Zinc-Air Batteries, Neng-Neng Xu, Jin-Li Qiao

Journal of Electrochemistry

Zinc-air battery has attracted great attention from researchers due to its high energy density and power density, which is expected to be widely used in energy conversion and storage. Air electrode as the core area of oxygen catalytic reaction is the focus of the entire zinc-air battery research. Recently, many research achievements have been made in non-noble metal bifunctional catalysts/electrodes with high activity, low cost and abundant species. In this review, we mainly focus on the reaction mechanism and the recent progress in non-noble metal oxide catalyst, carbon-based catalyst, and carbon-based transition metal compound composite and self-supporting electrode. In addition, …

Research Progress Of Metal-Nitrogen-Carbon Catalysts Toward Oxygen Reduction Reaction Inm Changchun Institute Of Applied Chemistry, Ming-Jun Xu, Jie Liu, Jun-Jie Ge, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

The development of highly active and stable catalysts toward oxygen reduction reaction (ORR) has been facing severe challenges. In recent years, pyrolytic M-N-C catalysts and metal-organic framework derived materials made the performance of non-noble metal catalysts greatly improved, however, the molecular and atomic level understanding in the reaction active sites and the mechanism are still lacking. Here, we summarize the recent research progress made in the Changchun Institute of Applied Chemistry. We present a microporous metal-organic-framework confined strategy toward the preferable formation of ORR catalysts. Firstly, we studied the active site and proposed a new active site structure for the …

Electrochemical Carbon Dioxide Reduction In Flow Cells, Jia Fan, Na Han, Yan-Guang Li

Journal of Electrochemistry

Electrochemical carbon dioxide reduction (CO₂RR) is an appealing approach to convert atmospheric CO₂ to value-added fuels and industrial chemicals, and may play an important role during the transition to a carbon-neutral economy. In order to make this technology commercially viable, it is essential to pursue CO₂RR in flow reactors instead of conventional H-type reactors, and to combine electrocatalyst development with system engineering. In this review, we overview the cell configurations and performance advantages of the two types of flow reactors, analyze their shortcomings, and discuss the effects of their different components including gas diffusion electrode …

Electrolyte Tailoring For Electrocatalytic Reduction Of Stable Molecules, Jin-Han Li, Fang-Yi Cheng

Journal of Electrochemistry

Reduction of stable molecules such as CO₂ and N₂ is important process in electrochemical energy conversion and storage technologies for electrofuels production. However, for the inert nature of CO₂/N₂ molecule and competitive proton reduction in conventional aqueous electrolytes, selective electrochemical carbon/nitrogen fixation suffers from high overpotential, low reaction rate and low selectivity. While addressing these issues has witnessed substantial advances in electrocatalysts, much less attention has been placed on the electrolytes, which play an important role in regulating the local environment and thus the performance of catalysts under operating conditions. Rational design of electrolytes has …

Fuel Cell Performance Of Non-Precious Metal Based Electrocatalysts, Yan-Feng Zhang, Fei Xiao, Guang-Yu Chen, Min-Hua Shao

Journal of Electrochemistry

The commercialization of proton exchange membrane fuel cells (PEMFCs) is hindered by high cost and low durability of Pt based electrocatalysts. Developing efficient and durable non-precious metal catalysts is a promising approach to addressing these conundrums. Among them, transition metals dispersed in a nitrogen (N)-doped carbon support (M-N-C) show good oxygen reduction reaction activity. This article reviews recent progress in M-N-C catalysts development, focusing on the catalysts design, membrane electrode assembly fabrication, fuel cell performance, and durability testing. Template-assisted approach is an efficient way to synthesize M-N-C materials with homogeneously dispersed single atom active site and reduced metal particles, carbides …

Protein Discrimination Using A Fluorescence-Based Sensor Array Of Thiacarbocyanine-Gumbos, Rocio L. Perez, Mingyan Cong, Stephanie R. Vaughan, Caitlan E. Ayala, Waduge Indika S. Galpothdeniya, John K. Mathaga, Isiah M. Warner

Faculty Publications

Sensitive and selective detection of proteins from complex samples has gained substantial interest within the scientific community. Early and precise detection of key proteins plays an important role in potential clinical diagnosis, treatment of different diseases, and proteomic research. In the study reported here, six different compounds belonging to a group of uniform materials based on organic salts (GUMBOS) have been synthesized using three thiacarbocyanine (TC) dyes and employed as fluorescent sensors. Fluorescence properties of micro- and nanoaggregates of these TC-based GUMBOS formed in phosphate buffer solutions are studied in the absence and presence of seven proteins. Fluorescence response patterns …

Electrochemical Energy Storage And Conversion Based On Organic Electrodes, Jian-Hang Huang, Xiao-Li Dong, Zhao-Wei Guo, Yuan-Yuan Ma, Yan-Rong Wang, Yong-Gang Wang

Journal of Electrochemistry

Aqueous batteries have been considered to be a competitive candidate for large-scale energy storage. However, most of aqueous batteries adopt inorganic electrode materials with metallic elements, which are based on the reversible insertion of metal ions, making their application being highly hindered by limited cycle life, environmental issue, high cost and low reserves. On the other hand, organic electrode materials offer the advantages of abundant reserves, tunable structures, renewability and environmental benignity. Furthermore, the wide internal space enables these organics to flexibly store various charge carriers. Organics have been investigated as the alternative to inorganic electrode materials. Herein, we review …

Recent Progress On Enhancing Effect Of Nanosized Metals For Electrochemical Co2 Reduction, Yu-Ning Zhang, Dong-Fang Niu, Shuo-Zhen Hu, Xin-Sheng Zhang

Journal of Electrochemistry

The electrochemical conversion of CO₂ to chemical raw material for further utilization shows promising future to alleviate global warming and realize carbon cycle in nature, which is of great significance to the green chemistry and sustainable development. This review briefly introduces the advantages of CO₂ electrochemical reduction (CO₂ER) and its basic reaction principles, and summarizes the recent progress in a series of activity enhancement strategies based on nanosized metal catalysts. The influences of alloy effect, interface engineering, synergistic effect, surface defect engineering and support effect on the catalytic performance of nanosized metals for CO₂ER …

Research Progresses Of Copper Interconnection In Chips, Lei Jin, Jia-Qiang Yang, Fang-Zu Yang, Dong-Ping Zhan, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

In this paper, the copper interconnection technology in chip manufacturing is introduced in detail, and the essentials of acidic copper sulfate electroplating process and the mechanisms of common-used additives are reviewed. The progresses of novel additives at home and abroad are also summarized. Based on the studied achievement, the possibility of the novel copper interconnect process replacing the acidic copper electroplating is prospected.

A Review Of Electrochemical Energy Storage Researches In The Past 22 Years, Yu-Sheng Yang

Journal of Electrochemistry

In this paper, research activities from my groups in the field of electrochemical energy storage are reviewed for the past 22 years, which is divided into three sections. The first section describes the researches related to high specific energy and high specific power energy storage devices, including lithium sulfur batteriies (sulfur composite cathode material, lithium sulfur battery fabrication, lithium boron alloy as lithium sulfur battery anodes, and sulfur lithium-ion battery new system), supercapacitors (super activated carbon, capacitive carbon prepared from phenolic resin, carbon nanotube array parasitic pseudo-capacitive energy storage materials, necessary properties of capacitive carbons, nickel hydroxide xerogels pseudo-capacitive energy …

Aerosol Mass And Optical Properties, Smoke Influence On O3, And High No3 Production Rates In A Western U.S. City Impacted By Wildfires, Vanessa Selimovic, Robert J. Yokelson, Gavin R. Mcmeeking, Sarah Coefield

Chemistry and Biochemistry Faculty Publications

Evaluating our understanding of smoke from wild and prescribed fires can benefit from downwind measurements that include inert tracers to test production and transport and reactive species to test chemical mechanisms. We characterized smoke from fires in coniferous forest fuels for >1,000 hr over two summers (2017 and 2018) at our Missoula, Montana, surface station and found a narrow range for key properties. ΔPM2.5/ΔCO was 0.1070 ± 0.0278 (g/g) or about half the age-independent ratios obtained at free troposphere elevations (0.2348 ± 0.0326). The average absorption Ångström exponent across both years was 1.84 ± 0.18, or about half the values …

An Investigation Of Antenna, Ligand Side-Chain, And Metal Ion Effects On The Optical And Mri Properties Of Bimodal Lanthanide (Iii) Complexes, Marisa Poveda

Master's Theses

Magnetic Resonance Imaging (MRI) is a leading anatomical imaging modality for disease diagnosis. With the aid of Gd³⁺ based contrast agents, high resolution images of biological structures can be obtained. However, there is an increased need for contrast agents that are responsive to specific analytes and chemical environments. Paramagnetic Chemical Exchange Saturation Transfer (PARACEST) agents that utilize a paramagnetic lanthanide ion chelated with a ligand have shown great promise in this area. Lanthanide ions also possess luminescence properties that do not suffer from common limitations of conventional optical imaging agents such as autofluorescence and photobleaching. The projects described in …

Designing A More Effective Mri Contrast Agent: Investigation Into Various Functionalization Strategies For Targeted Imaging, Lauren Nicole Rust

Dissertations and Theses

Magnetic resonance imaging (MRI) is a medical imaging technique that provides high-resolution images used for diagnostic medicine while maintaining a superior safety profile compared to other radiative techniques. The administration of gadolinium-based contrast agents (GBCAs) improves the diagnostic power of MRI and have been used clinically for over three decades. Although GBCAs are effective at improving the contrast in the image, their detection limits are high and require a large dose to generate an observable effect. This high dose is the consequence of the current available designs of clinical GBCAs; their structures are not tuned to generate optimal efficacy. Efficacy …

Functionalized Pyridine In Pyclen-Based Iron(Iii) Complexes: Evaluation Of Fundamental Properties, Magy A. Mekhail, Kristof Pota, Timothy M. Schwartz, Kayla N. Green

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The use of tetra-aza pyridinophanes is of increasing interest in the fields of bioinorganic modeling, catalysis, and imaging. However, a full study of how modifications to the pyridyl moiety affect the characteristics of the daughter metal complexes, has not been explored. In this study, six tetra-aza macrocyclic ligands were metalated with Fe(iii) and were characterized for the first time. The pyridyl functional groups studied include: 4-hydroxyl (L1), 4-H (L2), 4-chloro (L3), 4-trifluoromethyl (L4), 4-nitrile (L5), and 4-nitro (L6) modified pyridyl on a pyclen base structure. The resulting iron …

Electrospun Zno/Poly(Vinylidene Fluoride-Trifluoroethylene) Scaffolds For Lung Tissue Engineering, Bahareh Azimi, Mohammad Sajad Sorayani Bafqi, Alessandra Fusco, Claudio Ricci, Giuseppe Gallone, Roohollah Bagherzadeh, Giovanna Donnarumma, M. Jasim Uddin, Masoud Latifi, Andrea Lazzeri, Serena Danti

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Due to the morbidity and lethality of pulmonary diseases, new biomaterials and scaffolds are needed to support the regeneration of lung tissues, while ideally providing protective effects against inflammation and microbial aggression. In this study, we investigated the potential of nanocomposites of poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] incorporating zinc oxide (ZnO), in the form of electrospun fiber meshes for lung tissue engineering. We focused on their anti-inflammatory, antimicrobial and mechano-electrical character according to different fiber mesh textures (i.e., collected at 500 rpm and 4000 rpm) and compositions: (0/100) and (20/80) w/w% ZnO/P(VDF-TrFE), plain and composite, respectively. The scaffolds were characterized in terms …

Deciphering Tip-Enhanced Raman Imaging Of Carbon Nanotubes With Deep Learning Neural Networks., Usant Kajendirarajah, María Olivia Avilés, François Lagugné-Labarthet

Chemistry Publications

Recent release of open-source machine learning libraries presents opportunities to unify machine learning with nanoscale research, thus improving effectiveness of research methods and characterization protocols. This paper outlines and demonstrates the effectiveness of such a synergy with artificial neural networks to provide for an accelerated and enhanced characterization of individual carbon nanotubes deposited over a surface. Our algorithms provide a rapid diagnosis and analysis of tip-enhanced Raman spectroscopy mappings and the results show an improved spectral assignment of spectral features and spatial contrast of the collected images. Using several examples, we demonstrate the robustness and versatility of our deep learning …

Insights On Dissolved Organic Matter Production Revealed By Removal Of Charge-Transfer Interactions In Senescent Leaf Leachates, Karl M. Meingast, Brice K. Grunert, Sarah A. Green, Evan S. Kane, Nastaran Khademimoshgenani

Michigan Tech Publications, Part 1

Dissolved organic matter (DOM) is a critical part of the global carbon cycle. Currently, it is understood that at least a portion of the chromophoric DOM (CDOM) character can be described through an electronic interaction of charge transfer (CT) complexes. While much work has been done to understand the influence of CT on soil and aquatic reference standard DOM, little is known about the influence of CT in fresh terrestrially derived DOM. In this study, leaf litter leachates from three tree species were treated (reduced) with sodium borohydride to determine the contribution of CT on a source of fresh terrestrial …

Long Term Air Quality Analysis In Reference To Thermal Power Plants Using Satellite Data In Singrauli Region, India, H. K. Romana, Ramesh P. Singh, D. P. Shukla

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The exponentially growing population and related anthropogenic activities have led to modifications in local environment. The change in local environment, evolving pattern of land use, concentrations of greenhouse gases and aerosols alter the energy balance of our climate system. This alteration in climate is leading to pre-mature deaths worldwide. This study analyses the air quality of Singrauli region, Madhya Pradesh, India for the past 15 years. Otherwise known as Urjanchal “the energy capital” of India has been declared as critically polluted by CPCB. The study provides an updated list of thermal power plants in the study area and their emission …

The Bach1/Nrf2 Axis In Brain In Down Syndrome And Transition To Alzheimer Disease-Like Neuropathology And Dementia, Marzia Perluigi, Antonella Tramutola, Sara Pagnotta, Eugenio Barone, D. Allan Butterfield

Chemistry Faculty Publications

Down syndrome (DS) is the most common genetic cause of intellectual disability that is associated with an increased risk to develop early-onset Alzheimer-like dementia (AD). The brain neuropathological features include alteration of redox homeostasis, mitochondrial deficits, inflammation, accumulation of both amyloid beta-peptide oligomers and senile plaques, as well as aggregated hyperphosphorylated tau protein-containing neurofibrillary tangles, among others. It is worth mentioning that some of the triplicated genes encoded are likely to cause increased oxidative stress (OS) conditions that are also associated with reduced cellular responses. Published studies from our laboratories propose that increased oxidative damage occurs early in life in …

Recent Progress In Enhancing Poly(Lactic Acid) Stereocomplex Formation For Material Property Improvement, Fuhong Luo, Alexander Fortenberry, Jie Ren, Zhe Qiang

Faculty Publications

The production and utilization of polymers have been widely implemented into diverse applications that benefit modern human society, but one of the most valuable properties of polymers, durability, has posed a long-standing environmental challenge from its inception since plastic waste can lead to significant contamination and remains in landfills and oceans for at least hundreds of years. Poly(lactic acid) (PLA) derived from renewable resources provides a sustainable alternative to traditional polymers due to its advantages of comparable mechanical properties with common plastics and biodegradability. However, the poor thermal and hydrolytic stability of PLA-based materials limit their potential for durable applications. …

High-Frequency Data Reveal Differential Dissolved And Suspended Solids Behavior From A Mixed Restored Prairie And Agricultural Catchment, Andrew Miller, Ashlee L. Dere, Tracy Coleman

Chemistry Faculty Publications

Quantifying temporal variability and fluxes within hydrologic catchments is critical to understanding the underlying chemical and physical processes leading to material transport. Measuring variability and fluxes requires sampling at time scales similar to the time scale of process occurrence. This demand has led to the development of automated sampling systems designed to sample at high frequencies, on the order of minutes. While widely deployed in a variety of systems, we installed two high-frequency sampling devices in a single drainage comprised of restored prairie and agricultural land uses in temperate Eastern Nebraska. The sampling systems determined flow rate, conductivity, and turbidity …

Effect Of Carbon Hybridization In C—F Bond As An Electron Donor In Triel Bonds, Qingqing Yang, Zongqing Chi, Qingzhong Li, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The ability of the F atom of HC≡CF, H₂C=CHF and H₃CCH₂F to serve as an electron donor to the triel (Tr) atom of TrR₃ in the context of a triel bond is assessed by ab initio calculations. The triel bond formed by C_sp3—F is strongest, as high as 30 kcal/mol, followed by C_sp2—F, and then by C_sp—F whose triel bonds can be as small as 1 kcal/mol. The noncovalent bond strength diminishes in the order Tr = Al > Ga > B, consistent with the intensity of the π-hole …