Chemistry Commons^™

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 …

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.

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 …

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 …

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 …

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 …

Thermoresponsive Self-Immolative Polyglyoxylamides., Amir Rabiee Kenaree, Quinton E. A. Sirianni, Kyle Classen, Elizabeth R. Gillies

Chemistry Publications

Thermoresponsive polymers with lower critical solution temperatures (LCSTs) are of significant interest for a wide range of applications from sensors to drug delivery vehicles. However, the most widely investigated LCST polymers have nondegradable backbones, limiting their applications

The Bio3d Packages For Structural Bioinformatics, Barry J. Grant, Lars Skjærven, Xin-Qiu Joe Yao

Chemistry Faculty Publications

Bio3D is a family of R packages for the analysis of biomolecular sequence, structure, and dynamics. Major functionality includes biomolecular database searching and retrieval, sequence and structure conservation analysis, ensemble normal mode analysis, protein structure and correlation network analysis, principal component, and related multivariate analysis methods. Here, we review recent package developments, including a new underlying segregation into separate packages for distinct analysis, and introduce a new method for structure analysis named ensemble difference distance matrix analysis (eDDM). The eDDM approach calculates and compares atomic distance matrices across large sets of homologous atomic structures to help identify the residue wise …

Stay Calm And Focus On The Learning Outcomes: Tools For Taking Biophysical Chemistry Online, Maria Ballester, Brian L. Van Hoozen Jr., Arthur Sikora

Chemistry and Physics Faculty Articles

Course specific learning outcomes are an important tool to define the scope of a course and can be very helpful when designing experiments and assessments. With slight modification, these learning outcomes can serve as a guide when transitioning to the distance learning format especially in courses with a traditional lab. Here we present such an example for the biophysical chemistry course.

Structural Organization And Chemical Activity Revealed By New Developments In Single-Molecule Fluorescence And Orientation Imaging, Tianben Ding

McKelvey School of Engineering Graduate Student Theses & Dissertations

Single-molecule (SM) fluorescence and its localization are important and versatile tools for understanding and quantifying dynamical nanoscale behavior of nanoparticles and biological systems. By actively controlling the concentration of fluorescent molecules and precisely localizing individual single molecules, it is possible to overcome the classical diffraction limit and achieve 'super-resolution' with image resolution on the order of 10 nanometers.

Single molecules also can be considered as nanoscale sensors since their fluorescence changes in response to their local nanoenvironment. This dissertation discusses extending this SM approach to resolve heterogeneity and dynamics of nanoscale materials and biophysical structures by using positions and orientations …

Development And Application Of Mass Spectrometry-Based Approaches For Protein Higher Order Structure Analysis And Protein-Protein Interaction Characterization, Mengru Zhang

Arts & Sciences Graduate Student Theses and Dissertations

Proteins, one of the most fundamental biomolecules, adopt unique higher order structures (HOS) to enable diverse biological functions. Deciphering protein HOS is crucial to gain deeper insights of their working mechanisms and to develop biotherapeutics. Mass spectrometry (MS)-based approaches evolved rapidly in the past 30 years and are now playing critical roles in protein HOS characterization. One of those approaches is MS-based footprinting whose principle is to map the solvent accessible surface area (SASA) to deliver structural information. Protein footprinting can be achieved by reversible labeling, e.g., hydrogen-deuterium exchange (HDX), and by irreversible labeling using radical-based reagents or other targeted …

Production Of Medical Radioisotopes Using Titanium Accelerator Targets, Christopher Shaun Loveless

Arts & Sciences Graduate Student Theses and Dissertations

Theranostic radiopharmaceuticals enable diagnostic imaging and radionuclide therapy in patients using a single molecular agent labeled with a diagnostic-therapeutic pair (e.g., 68Ga/177Lu) or a theranostic radionuclide (e.g., 131I). This theranostic approach can help inform patient-specific treatment plans and improve clinical outcomes. Radionuclide pairs used in theranostic agents fall into two categories: pseudo matched-pairs (e.g., 68Ga/177Lu) and matched-pairs (e.g., 124I/131I). Pseudo matched-pair radionuclides have similar chemistries and pharmacokinetics when bound to the same bioconjugate molecule. In contrast, identical chemistries and pharmacokinetics can be obtained by using the matched-pair radionuclides.The isotopes of Sc include two diagnostic radioisotopes, 43Sc & 44Sc, and one …

Transition Metal Complexes Of Pyridyltriazole And Bipyridine Ligands, Sen Gao

LSU Doctoral Dissertations

Four Ni(II) complexes have been obtained with the pyridyltriazole ligand, bpt, or the bis(pyridyltriazole) ligand, m-xpt, in chapter 2. This work was carried out as a comparison with the previously established coordination chemistry of copper(II) with bpt and m-xpt. Initially, the reaction between Ni(II) and bpt only produced one mononuclear compound, [Ni(bpt)₂(H₂O)₂](NO₃)₂ (1). In order to study the formation of Ni-bpt and Ni-m-xpt complexes in solution, mixtures of Ni(NO₃)₂ and ligand (m-xpt or bpt) were prepared in different ratios and …