Chemistry Commons^™

Alignment Of Theoretically Grounded Constructs For The Measurement Of Science And Chemistry Identity, Kathryn Nicole Hosbein, Jack Barbera

Chemistry Faculty Publications and Presentations

Identity has been theorized to aid in student persistence within STEM disciplines. In this study, science and chemistry identity were defined as being recognized as a science or chemistry person within the classroom. To generalize the effects that identity has on student persistence, a measurable construct must be defined, operationalized, and tested in multiple settings with different populations. This project addressed the first step in the process, defining the construct and grounding it in an established theoretical framework. This qualitative project utilized a previously described physics identity framework, with sub-constructs of performance/competence, recognition, and interest, as a starting point for …

Structure-Property-Function Connections Underlying Performance Of Polybenzoxazole Membranes Derived From Bisapaf Polyimides, Maram A. Q. Al-Sayaghi, Jeremy Lewis, Chris Buelke, Ali Alshami

Chemical Engineering Faculty Publications

Highlights

• Stable rigid monomers result in polyimides with higher Mw, Tg, TR, and the more superior separation performance.
• Thermal rearrangement improved ideal gas separation by 1.5 to 2.0 orders of magnitude.
• Thermal rearrangement resulted in an enhanced thermal, mechanical and chemical properties of the produced membranes.

Polymeric membranes remain and will most likely continue to be the most practical cost-effect chemical constructs for gas separation processes, provided that novel polymers are developed to overcome current and persisting limitations facing exiting membranes. Here, we report a methodical and systematic study of the structure-property-function relations of standard polyimide membranes and their implications …

Charging And Supercharging Of Proteins For Mass Spectrometry: Recent Insights Into The Mechanisms Of Electrospray Ionization., Lars Konermann, Haidy Metwally, Quentin Duez, Insa Peters

Chemistry Publications

Electrospray ionization (ESI) is an essential technique for transferring proteins from solution into the gas phase for mass spectrometry and ion mobility spectrometry. The mechanisms whereby [M + zH]^z+ protein ions are released from charged nanodroplets during ESI have been controversial for many years. Here we discuss recent computational and experimental studies that have shed light on many of the mysteries in this area. Four types of protein ESI experiments can be distinguished, each of which appears to be associated with a specific mechanism. (i) Native ESI proceeds according to the charged residue model (CRM) that entails droplet evaporation …

Stretchable Self-Healable Semiconducting Polymer Film For Active-Matrix Strain-Sensing Array, Jin Young Oh, Donghee Son, Toru Katsumata, Yeongjun Lee, Yeongin Kim, Jeffrey Lopez, Hung-Chin Wu, Jiheong Kang, Joonsuk Park, Xiaodan Gu, Jaewan Mun, Nathan Ging-Ji Wang, Yikai Yin, Wei Cai, Youngjun Yun, Jeffrey B.-H. Tok, Zhenan Bao

Faculty Publications

Skin-like sensory devidces shoud be stretchable and self-healable to meet the demands for future electronic skin applications. Despite recent notable advances in skin-inspired electronic materials, it remains challenging to confer these desired functionalities to an active semiconductor. Here, we report a strain-sensitive, stretchable, and autonomously self-healable semiconducting film achieved through blending of a polymer semiconductor and a self-healable elastomer, both of which are dynamically cross-linked by metal coordination. We observed that by controlling the percolation threshold of the polymer semiconductor, the blend film became strain sensitive, with a gauge factor of 5.75 x 10⁵ at 100% strain in a …

Sustainable Solutions, Fall/Winter 2020, Issue 41

Sustain Magazine

No abstract provided.

Performance Of Concrete Made With A Calcined Clay – Limestone-Portland Cement Exposed To Natural Conditions, Fernando Martirena, Ernesto Díaz, Dayran Rocha, Hamed Maraghechi, Karen Louise Scrivener

International Conference on Durability of Concrete Structures

This work presents the results of an investigation carried out to assess durability of concrete made with a calcined clay- limestone-Portland cement with 47% of clinker, hereafter named LC3, produced during an industrial trial in 2013. LC3 was used to cast concrete blocks and later expose them at a natural location at the northern coast of Cuba. Reference concrete was cast with Cuban Portland cement having 88% of clinker. Throughout three years (2015, 2016, 2017) concrete cores were systematically taken and the specimens were subjected to a testing program that included Formation factor, chloride profiling, surface resistivity, air permeability and …

Formulation To Application: Thermomechanical Characterization Of Flexible Polyimides And The Improvement Of Their Properties Via Chain Interaction, Alejandro Rivera Nicholls

USF Tampa Graduate Theses and Dissertations

In this work, Polyimides were synthesized by incorporating an aromatic diamine monomer with a methylene linker, 4,4'-methylenebis(2,6-dimethylaniline) (MBDMA), to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to reduce rigidity. The polymers were designed to exhibit thermal properties in between those of conventional aromatic polyimides and polymers with wholly aliphatic ether diamine links. Through dynamic mechanical analysis and differential scanning calorimetry, it is shown that control of the molar ratios of the aromatic MBDMA and the composition and size of the aliphatic polyetherdiamine can be used to tune the glass transition temperature. The materials were characterized and …

Root Cause Analysis And Method Development Of Calorimetry Experiments, Anya M. Deaton, Lydia R. Deaton, John M. Farrar Dr.

Posters-at-the-Capitol

First year chemistry students learn a broad range of concepts that are also proven out in the lab environment. These concepts are a basis for a solid foundation for future chemistry learning. When the lab experiments don’t produce the expected results, students understanding in these concepts diminish and overall confidence and grades suffer. Our project details the root cause analysis and subsequent method development work for two experiments related to calorimetry; heat of solution and freezing point depression. The team sought to refine these experiments after finding that many of the students were unable to generate the expected results for …

Medicaments In Preventing Iodine Deficiency, And Their Chemical Composition, I. R. Asqarov Doctor Of Chemical Sciences, Professor, A. S. Xojiqulov Teacher

Scientific journal of the Fergana State University

The article discusses the causes of iodine deficiency, the state of the spread of iodine deficiency in the world and in the Republic of Uzbekistan, synthetic and natural remedies used for its treatment are described from the information given in writing supplements, used as the “Alcoman” medicinal product, as well as methods for making tincture from it and its use.

Synthesis Of The Betulinic Acid, Sh. Sh. Turg‘Unboyev Base Doctoral Student, A. X. Xaitbayev Doctor Of Chemical Sciences, Associate Professor

Scientific journal of the Fergana State University

Today, one of the most important tasks for the further development of the pharmaceutical industry is medicines obtained from local raw materials. This article describes the production of betulin from the bark of the Betula pendula tree growing in the territory of Uzbekistan, the synthesis of various derivatives based on it, and the study of the structure of substances by physical methods. Based on these studies, medicines will be created from local raw materials.

Beer Classification And Certification Based On Chemical Composition, D. T. Xasanova Doctor Of Philosophy In Chemical Sciences (Phd), I. R. Asqarov Doctor Of Chemical Sciences, Professor

Scientific journal of the Fergana State University

The article analyzes the physical-chemical indicators that determine the commodity status characteristic of beer products, gives criteria for differentiating existing product codes and assigning product codes to the new types of products, as well as the features of applying new express analysis methods.

An Efficient Viologen-Based Electron Donor To Nitrogenase, Artavazd Badalyan, Zhi-Yong Yang, Bo Hu, Jian Luo, Maowei Hu, T. Leo Liu, Lance C. Seefeldt

Chemistry and Biochemistry Faculty Publications

Nitrogenase catalyzes the reduction of N₂ to NH₃, supporting all biological nitrogen fixation. Electron donors to this enzyme are ferredoxin or flavodoxin (in vivo) and sodium dithionite (in vitro). Features of these electron donors put a limit on spectrophotometric studies and electrocatalytic applications of nitrogenase. Although it is common to use methyl viologen as an electron donor for many low-potential oxidoreductases, decreased nitrogenase activity is observed with an increasing concentration of methyl viologen, limiting its utility under many circumstances. In this work, we suggest that this concentration-dependent decrease in activity can be explained …

The Total Syntheses Of Jbir-94 And Two Synthetic Analogs And Their Cytotoxicities Against A549 (Ccl-185) Human Small Lung Cancer Cells, Cathy L. Mangum, Mica B. Munford, Alyssa Sam, Sandra K. Young, Jeremy T. Beales, Yagya Prasad Subedi, Chad D. Mangum, Tanner J. Allen, Miranda S. Liddell, Andrew I. Merrell, Diana I. Saavedra, Becky L. Williams, Nicole Evans, Joseph L. Beales, Mike A. Christiansen

Chemistry and Biochemistry Faculty Publications

We here disclose the total syntheses of the natural polyphenol JBIR-94 and two nonnatural analogs, whose structures are of interest for their bioactivity potential as radical scavengers. Although we initially attempted this by dually acylating both of putrecine’s amine nitrogens in a single pot, our endeavors with this method (which has been successfully reported by other groups) proved ineffectual. We accordingly opted for the lengthier approach of acylating each amine individually, which gratuitously prevailed and also aligns with separate literature precedent. Moreover, we here share our analysis of these target compounds’ cytotoxicities and IC₅₀ values against A549 (CCL-185) human …

Decorative Articles Based On Polymeric Materials, Yaser M. Asal Mr., M. A. Radwan, Hany A. Elazab Dr, Bassant Hussein, Mohamed A. Sadek

Chemical Engineering

The aim of the research is to create decorative articles based on polymeric materials, study the effects of fillers and the type of moulds that it can cope with the exothermic reaction nature of resin to create a scientific background on the usage of the resins in daily life products. The polymeric materials that will be concentrated on are the unsaturated polyester resins and epoxy resins. The unsaturated polyester is of many types and chemical constituents, the used experimentally is a general-purpose type and the epoxy also have different types and the used is a commercially 3D floor coating type. …

End-Point Modification Of Recombinant Thrombomodulin With Enhanced Stability And Anticoagulant Activity, Xia Liu, Mallorie Boron, Yu Zhao, Xue-Long Sun

Chemistry Faculty Publications

Thrombomodulin (TM) is an endothelial cell membrane protein that plays essential roles in controlling vascular haemostatic balance. The 4, 5, 6 EGF-like domain of TM (TM₄₅₆) has cofactor activity for thrombin binding and subsequently protein C activation. Therefore, recombinant TM₄₅₆ is a promising anticoagulant candidate but has a very short half-life. Ligation of poly (ethylene glycol) to a bioactive protein (PEGylation) is a practical choice to improve stability, extend circulating life, and reduce immunogenicity of the protein. Site-specific PEGylation is preferred as it could avoid the loss of protein activity resulting from nonspecific modification. We report herein …

Detection Of Chalk In Single Kernels Of Long-Grain Milled Rice Using Imaging And Visible/Near-Infrared Instruments, Christopher K. Addison

Faculty Publications

Background and objectives To maintain the competitiveness of U.S. long-grain rice in U.S. and foreign markets, having translucent whole milled grain is critical. An objective technique to detect grain chalk, opaque areas in the grain, will provide breeders and industry with an effective tool for developing low-chalk varieties or agronomic practices that reduce chalk occurrence. Two instruments developed at the Center for Grain and Animal Health Research, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), a single-kernel near-infrared (SKNIR) tube instrument and a silicon-based light-emitting diode (SiLED) high-speed sorter, were compared with two commercially available imaging instruments, WinSEEDLE and SeedCount used …

Emergent Functional Behaviour Of Humic Substances Perceived As Complex Labile Aggregates Of Small Organic Molecules And Oligomers, Robert L. Cook

Faculty Publications

The structural organisation of humic substances (HS) has been a central question of earth sciences for several decades. The latest experimental results have led to the recognition of HS as complex mixtures of small molecules and oligomers. We investigate the correlation between the chemical composition of HS, perceived as labile aggregates, and the emergent functions. Computational modelling was used to help to understand the processes and mechanisms on the molecular scale that occur in different fractions of the HS, fulvic acids (FA) and humic acids (HA), as they interact with metal ions and organic pollutants. The importance of non-covalent interactions …

Chemical Process Development, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet on the Energy & Environmental Research Center’s chemical process development capabilities, facilities and equipment, and history. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

Enhanced Piezoresponse And Nonlinear Optical Properties Of Fluorinated Self-Assembled Peptide Nanotubes, Soma Khanra, Sandra V. Vassiliades, Wendel A. Alves, Kaidi Yang, Rainer Glaser, Kartik Ghosh, Payal Bhattacharya, Ping Yu, Suchismita Guha

Chemistry Faculty Research & Creative Works

Self-assembled L,L-diphenylalanine (FF) nanostructures offer an attractive platform for photonics and nonlinear optics. The nonlinear optical (NLO) coefficients of FF nanotubes depend on the diameter of the tube [S. Khanra et al. Phys. Chem. Chem. Phys. 19(4), 3084-3093 (2017)]. To further enhance the NLO properties of FF, we search for structural modifications. Here, we report on the synthesis of fluorinated FF dipeptides by replacing one ortho-hydrogen atom in each of the phenyl groups of FF by a fluorine atom. Density-functional theoretical calculations yield insights into minimum energy conformers of fluorinated FF (Fl-FF). Fl-FF self-assembles akin to FF into micron-length tubes. …

Optimization Of Electrospray Ionization For Liquid Chromatography Time-Of-Flight Mass Spectrometry Analysis Of Preservatives In Wood Leachate Matrix, Kukowski Klara, Gysbers Brianna, Stephen Fisher, Alena Kubatova

Chemistry Faculty Publications

Triazoles and 3-iodo-2-propynyl butylcarbamate (IPBC) are commonly used wood preservatives active against a wide range of fungi and bacteria. As they are prone to leaching, their amounts need to be monitored by the industry to determine preservative loss from the products and for environmental impact assessment. Therefore, a liquid chromatography–electrospray–time-of-flight mass spectrometry (LC–ESI–TOFMS) method was developed and optimized for simultaneous quantification of triazoles and IPBC in aqueous wood extracts, specifically wood leachate. Analyte pre-concentration on a solid-phase extraction cartridge prior to the analysis yielded > 94% recoveries. ESI method parameters (e.g., solvent system, electrolyte type, electrolyte concentration, capillary and fragmentor voltages) …

Development Of Novel Peroxidase-Tio2/Zno Hybrid Catalysts For The Degradation Of Emerging Pollutants, Rana Fawzi Mohamed

Theses

Water pollution by different organic compounds is one of the most important environmental issues that is attracting the attention of many scientists due to its direct potential bad effect on human health. These organic pollutants include pesticides, pharmaceuticals, industrial wastes, and personal care products that are released in water bodies from domestic and industrial discharge. Various chemical, physical and biological approaches have been proposed to degrade these contaminants from the polluted water. In the present study, we immobilized versatile thermostable enzymes, Soybean peroxidase (SBP) and Horseradish peroxidase on functionalized photocatalysts—TiO₂ and ZnO to create novel bio-composite catalysts (SBP-TiO₂, SBP-ZnO, HRP-TiO₂, …

How Oxygen Availability Affects The Antimicrobial Efficacy Of Host Defense Peptides: Lessons Learned From Studying The Copper-Binding Peptides Piscidins 1 And 3, Adenrele Oludiran, David S. Courson, Malia D. Stuart, Anwar R. Radwan, John C. Putsma, Myriam L. Cotten, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

The development of new therapeutic options against Clostridioides difficile (C. difficile) infection is a critical public health concern, as the causative bacterium is highly resistant to multiple classes of antibiotics. Antimicrobial host-defense peptides (HDPs) are highly effective at simultaneously modulating the immune system function and directly killing bacteria through membrane disruption and oxidative damage. The copper-binding HDPs piscidin 1 and piscidin 3 have previously shown potent antimicrobial activity against a number of Gram-negative and Gram-positive bacterial species but have never been investigated in an anaerobic environment. Synergy between piscidins and metal ions increases bacterial killing aerobically. Here, we …

Alginate/Cucurbit [7] Uril/Dequalinium–Basedb Supramolecular Carbohydrates: Modulation Of Fret Signal By Temperature Control, Amir Alam Sohail

Chemistry Theses

Herein, we describe the synthesis of a bioactive, inexpensive, and easy-tohandle supramolecular carbohydrate polymer by grafting of cucurbit [7] uril macrocycle (CB7)-encapsulated dequalinium chloride hydrate (DCH) onto alginic acid carbohydrates (ALG) via amide linkage formation and show that light energy transfer based on energy migration can be controlled by altering polymer temperature without changing polymer composition. DCH (donor) and 2-anilinonaphthalene-6- sulfonic acid (acceptor) were used to generate Förster resonance energy transfer (FRET) signals. Stationary and time-resolved photoluminescence spectra of the modified carbohydrate platform revealed that FRET resulted in a color change from violet (~387 nm) to blue (~429 nm), which …

Hierarchical Nanostructuring Of Porous Silicon With Electrochemical And Regenerative Electroless Etching, Ermei Mäkilä, Anne-Mari Anton Willmore, Haibo Yu, Marianna Irri, Mark Aindow, Tambet Teesalu, Leigh Trevor Canham, Kurt W. Kolasinski, Jarno Salonen

Chemistry Faculty Publications

Hierarchically nanostructured silicon was produced by regenerative electroless etching (ReEtching) of Si powder made from pulverized anodized porous silicon. This material is characterized by ∼15 nm mesopores, into the walls of which tortuous 2–4 nm pores have been introduced. The walls are sufficiently narrow that they support quantum-confined crystallites that are photoluminescent. With suitable parameters, the ReEtching process also provides control over the emission color of the photoluminescence. Ball milling and hydrosilylation of this powder with undecylenic acid produces nanoparticles with hydrodynamic diameter of ∼220 nm that exhibit robust and bright luminescence that can be excited with either one ultraviolet/visible …

Tools For Prescreening The Most Active Sites On Ir And Rh Clusters Toward C−H Bond Cleavage Of Ethane: Nbo Charges And Wiberg Bond Indexes, Yingbin Ge, Anna Le, Gregory J. Marquino, Phuc Q. Nguyen, Kollin Trujillo, Morgan Schimelfenig, Ashley Noble

All Faculty Scholarship for the College of the Sciences

B3LYP calculations were carried out to study the insertion of iridium (Ir) and rhodium (Rh) clusters into a C−H bond of ethane, which is often the ratelimiting step of the catalytic cycle of oxidative dehydrogenation of ethane. Our previous research on Ir catalysis correlates the diffusivity of the lowest unoccupied molecular orbital of the Ir clusters and the relative activities of the various catalytic sites. The drawback of this research is that the molecular orbital visualization is qualitative rather than quantitative. Therefore, in this study on C−H bond activation by the Ir and Rh clusters, we conducted analyses of natural …

Development And Evaluation Of Silica-Based Lectin Microcolumns For Glycoform Analysis Of Alpha1-Acid Glycoprotein, Chenhua Zhang, David S. Hage

David Hage Publications

Silica-based lectin microcolumns were developed and optimized for the separation and analysis of glycoform fractions in alpha1-acid glycoprotein (AGP) based on both the degree of branching and level of fucosylation. Concanavalin A (Con A) and Aleuria Aurantia lectin (AAL) were immobilized onto HPLC-grade silica by reductive amination and packed into 2.1 mm i.d. × 5.0 cm microcolumns. Factors examined for these microcolumns include their protein content, binding capacity, binding strength and band-broadening under isocratic conditions (Con A) or step elution conditions (AAL) and in the presence of various flow rates or temperatures. These factors were examined by using experiments based …

Thermo-Oxidative Degradation Of Hdpe Geomembranes: Effect Of Phenolic Antioxidant And Hindered Amine Light Stabilizer Concentrations, Yasin Kocak

USF Tampa Graduate Theses and Dissertations

High density polyethylene (HDPE) geomembrane is most common geomembrane which is mainly used for civil engineering applications. However, HDPE geomembrane loses its properties under oxidative degradation progress. This study aims to assess geomembranes which have different percentage of phenolic antioxidant and hindered amine light stabilizer (HALS) with under the six months of the thermal-oxidative degradation. The interactions between phenolic antioxidant, HALS and carbon black can affect the mechanical, physical and chemical properties. To monitor these properties, Differential Scanning Calorimetry (DSC), Fourier-transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectroscopy (SEM/EDX), Melt Index tests, …

Evaluating The Evidence Base For Evidence-Based Instructional Practices In Chemistry Through Meta-Analysis, Md Tawabur Rahman

USF Tampa Graduate Theses and Dissertations

Investigating the effectiveness of instructional practices provides an evidence base to inform instructional decisions. Synthesizing research studies on instructional effectiveness provides an estimate of the generalizability of effectiveness across settings, along with an exploration of factors that may moderate the impact, which cannot be achieved within individual studies. This study sought to provide a synthesis of evidence- based instructional practices (EBIPs) particular to chemistry through meta-analysis. 99 studies were analyzed comprising a broader view of chemistry specific studies than past meta-analyses. The results showed that EBIPs feature a demonstrably positive impact on students’ academic performance in chemistry, although assessment topic …

Near Real-Time Determination Of The Prevalence Of Cannabinoids, Cathinones, And Synthetic Opioids, Catherine O'Rourke, Bikram Subedi

Scholars Week

Unregulated new psychoactive substances (NPS) in “pure” or “preparation” forms are designed to mimic the effects of controlled substances, and are introduced and reintroduced in the market as a cheap substitute of established regulated drugs in quick succession to loophole the law enforcement efforts on combating drugs. For example, carfentanil, a synthetic opioid activates the opioid receptors similar to morphine but it is astoundingly potent compared to a typical drug of abuse (100 times more potent than fentanyl and 10,000 times more powerful than morphine). Based on the cost- and time-intensive forensic analysis, National Drug Early Warning System reported the …

Progress In Solar Photocatalytic Hydrogen Production, Zhi Wu, Lan Sun, Chang-Jian Lin

Journal of Electrochemistry

With the rapid development of human society and dramatically consumption of traditional energy, energy shortage and environmental pollution have become an important factor restricting the sustainable development of human society. At present, the development of clean and environmentally friendly renewable energy system has drawn much attention and becomes an important priority stratagem in the world. In many green and sustainable new energy projects, semiconductor-based photocatalytic hydrogen production technology which utilizes the available clean and renewable solar energy to prepare clean hydrogen energy is excepted to solve the crisis of energy shortage and environmental pollution, has become one of the most …