Chemistry Commons^™

Surface Structure And Phase Composition Of Tio2 P25 Particles After Thermal Treatments And Hf Etching, M. Jasim Uddin, Federico Cesano, Aminur Rashid Chowdhury, Tarek Trad, Sara Cravanzola, Gianmario Martra, Lorenzo Mino, Adriano Zecchina, Domenica Scarano

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

The anatase to rutile phase transformation via thermal and chemical (HF etching) routes of TiO2 P25 has been investigated. The treatment parameters and properties of the resulting anatase and rutile nanoparticles are analyzed and discussed. Since the nature of TiO2 surfaces plays a significant role in determining the physical and chemical properties of the TiO2 nanoparticles, it is important to investigate the surface properties, including the morphology, the main exposed faces, the defectiveness, to be correlated with their peculiar properties, and then reactivity. Herein, we report an infrared spectroscopy investigation, employing the adsorption of CO probe molecule at low temperature, …

Hydrogen Peroxide And Antioxidant Enzymes Moderate Interaction Of The Carbon And Oxygen Cycles At The Redoxcline, Fan Wang

Theses and Dissertations

Hydrogen peroxide is a reduced form of dioxygen produced in natural waters from a manifold of abiotic and biological processes. Hydrogen peroxide is highly redox active and it often serves to initiate the formation of reactive oxygen species in the environment. It typically exists in natural waters at concentrations ranging from as low as ~ 1 nanomolar in “blue water” marine environments to as high as 10 micromolar near actively effluxing sediments. It has the potential to cause significant toxicity in aquatic organisms, which have evolved a collection of antioxidant enzymes including peroxidase, catalase, and superoxide dismutase. Work in this …

Three-Event Energy Detection With Adaptive Threshold For Spectrum Sensing In Cognitive Radio Systems, Alexandru Martian, Mahmood Jalal Ahmad Al Sammarraie, Calin Vladeanu, Dimitrie Popescu

Electrical & Computer Engineering Faculty Publications

Implementation of dynamic spectrum access (DSA) in cognitive radio (CR) systems requires the unlicensed secondary users (SU) to implement spectrum sensing to monitor the activity of the licensed primary users (PU). Energy detection (ED) is one of the most widely used methods for spectrum sensing in CR systems, and in this paper we present a novel ED algorithm with an adaptive sensing threshold. The three-event ED (3EED) algorithm for spectrum sensing is considered for which an accurate approximation of the optimal decision threshold that minimizes the decision error probability (DEP) is found using Newton’s method with forced convergence in one …

An Angelman Syndrome Substitution In The Hect E3 Ubiquitin Ligase C-Terminal Lobe Of E6ap Affects Protein Stability And Activity, Steven A. Beasley, Chloe E. Kellum, Rachel J. Orlomoski, Feston Idrizi, Donald E. Spratt

Chemistry

Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by speech impairment, intellectual disability, ataxia, and epilepsy. AS is caused by mutations in the maternal copy of UBE3A located on chromosome 15q11-13. UBE3A codes for E6AP (E6 Associated Protein), a prominent member of the HECT (Homologous to E6AP C-Terminus) E3 ubiquitin ligase family. E6AP catalyzes the posttranslational attachment of ubiquitin via its HECT domain onto various intracellular target proteins to regulate DNA repair and cell cycle progression. The HECT domain consists of an N-lobe, required for E2~ubiquitin recruitment, while the C-lobe contains the conserved catalytic cysteine required for ubiquitin transfer. …

An Experimental Investigation Of Liquid Hydrocarbons In A Simulated Titan Environment, Kendra Farnsworth

Graduate Theses and Dissertations

Saturn’s moon, Titan, has surface conditions (89–94 K, 1.5-bar atmosphere) that permit lakes of methane, ethane, and dissolved atmospheric nitrogen. The effects of atmospheric nitrogen on methane-ethane liquid properties is poorly understood, leading to uncertainty in Titan modeling. I address this question by experimentally investigating the physical properties of methane-ethane liquids under a 1.5-bar nitrogen atmosphere in a simulated Titan environmental chamber.

Chapter 1 addresses nitrogen dissolution kinetics in Titan’s liquid hydrocarbons. I found an exponential increase in nitrogen quantity and diffusion coefficients with increasing methane mol%. I find that Titan’s liquids are likely not saturated in nitrogen, with dissolution …

Thiophene Derivative Monomers Co-Electropolymerized On Microelectrodes Within Arrays For Tailored Surface Chemistry And Electrochemical Properties, Benjamin J. Jones

Graduate Theses and Dissertations

Potentiodynamic co-electropolymerization of two thiophene derivatives, (2,3-dihydrothieno[3,4-b]dioxin-2-yl)methanol (1) and 4-((2,3-dihydrothieno[3,4-b][1,4]dioxin-2-yl)-methoxy)-4-oxobutanoic acid (2), in aqueous solutions (0.02 M total monomer, 0.05 M sodium dodecyl sulfate (SDS) and 0.1 M LiClO4) on gold microband electrodes in an array was investigated. A modified Steglich esterification reaction between monomer 1 and succinic anhydride produced monomer 2 at 93.6% yield. Seven deposition solutions of the two monomers, defined by mol% of monomer 2 (0, 25, 34, 50, 66, 75, 100) generated seven sets of polymer films by cyclic voltammetry in a specially designed cell to conserve monomer. The onset potential for monomer oxidation and total …

Resonance Raman Spectroscopic Studies Of Peroxo And Hydroperoxo Intermediates In Lauric Acid (La)-Bound Cytochrome P450 119, Remigio Usai, Daniel Kaluka, Piotr J. Mak, Yilin Liu, James R. Kincaid

Chemistry Faculty Research and Publications

Cytochromes P450 bind and cleave dioxygen to generate a potent intermediate compound I, capable of hydroxylating inert hydrocarbon substrates. Cytochrome P450 119, a bacterial cytochrome P450 that serves as a good model system for the study of the intermediate states in the P450 catalytic cycle. CYP119 is found in high temperature and sulfur rich environments. Though the natural substrate and redox partner are still unknown, a potential application of such thermophilic P450s is utilizing them as biocatalysts in biotechnological industry; e.g., the synthesis of organic compounds otherwise requiring hostile environments like extremes of pH or temperature. In the present work …

Mqct: User-Ready Program For Calculations Of Inelastic Scattering Of Two Molecules, Alexander Semenov, Bikramaditya Mandal, Dmitri Babikov

Chemistry Faculty Research and Publications

A program named MQCT is developed for calculations of rotationally and vibrationally inelastic scattering of molecules using the mixed quantum/classical theory approach. Calculations of collisions between two general asymmetric top rotors are now possible, which is a feature unavailable in other existing codes. Vibrational states of diatomic molecules can also be included in the basis set expansion, to carry out calculations of ro-vibrational excitation and quenching. Minimal input for the code assumes several defaults and is very simple, easy to set-up and run by non-experts. Multiple options, available for expert calculations, are listed in the Supplemental Information. The code is …

Probing Cooperativity In C–H⋯N And C–H⋯Π Interactions: Dissociation Energies Of Aniline⋯(Ch4)N (N = 1, 2) Van Der Waals Complexes From Resonant Ionization And Velocity Mapped Ion Imaging Measurements, James Makuvaza, John L. Loman, Damian L. Kokkin, Scott A. Reid

Chemistry Faculty Research and Publications

Recent studies of the weakly bound anisole⋯CH₄ complex found a dual mode of binding, featuring both C/H⋯π and C/H⋯O noncovalent interactions. In this work, we examine the dissociation energies of related aniline⋯(CH₄)_n (n = 1, 2) van der Waals clusters, where both C/H⋯π and C/H⋯N interactions are possible. Using a combination of theory and experiments that include mass-selected two-color resonant two-photon ionization spectroscopy, two-color appearance potential (2CAP) measurements, and velocity-mapped ion imaging (VMI), we derive the dissociation energies of both complexes in the ground (S₀), excited (S₁), and cation radical (D …

Crystal Structure Of 4-Methyl-N-Propyl­Benzene­Sulfonamide, Brock A. Stenfors, Rachel C. Collins, Jonah R.J. Duran, Shannon Biros, Felix Ngassa

Open Access Publishing Support Funded Articles

The crystal structure of the title sulfonamide, C₁₀H₁₅NO₂S, comprises two mol­ecules in the asymmetric unit. The S=O bond lengths of the sulfonamide functional group range from 1.428 (2) to 1.441 (2) Å, with S—C bond lengths of 1.766 (3) Å (for both mol­ecules in the asymmetric unit), and S—N bond lengths of 1.618 (2) and 1.622 (3) Å, respectively. When both mol­ecules are viewed down the N—S bond, the propyl group is gauche to the toluene moiety. In the crystal structure, mol­ecules of the title compound are arranged in an intricate three-dimensional network that …

Crystal Structure Of N,N-Diiso­Propyl-4-Methyl­Benzene­Sulfonamide, Brock A. Stenfors, Richard J. Staples, Shannon Biros, Felix Ngassa

Open Access Publishing Support Funded Articles

The synthesis of the title compound, C13H21NO2S, is reported here along with its crystal structure. This compound crystallizes with two mol­ecules in the asymmetric unit. The sulfonamide functional group of this structure features S=O bond lengths ranging from 1.433 (3) to 1.439 (3) Å, S—C bond lengths of 1.777 (3) and 1.773 (4) Å, and S—N bond lengths of 1.622 (3) and 1.624 (3) Å. When viewing the mol­ecules down the S—N bond, the isopropyl groups are gauche to the aromatic ring. On each mol­ecule, two methyl hydrogen atoms of one isopropyl group are engaged in intra­molecular C—H⋯O hydrogen bonds …

Features Of Heart Activity Of Cattle In The Conditions Of Southern Aral Sea Region, Svetlana Mambetullaeva, Khayratdin Seytkamalov

Karakalpak Scientific Journal

In this article, the results of comparative analysis of electrocardiogram are shown for the cows of different breeds in the Aral Sea region. It is set that the high temperature of the environment and sunny insolation render a negative influence on the functional parameters of the cardiac vascular system of animals. There are facts about the cows of different breeds at the influence of different temperatures that have unidirectional functional changes in the operation of the heart. At the same time, we will mark that these changes are less expressed for the cows of the improved zebu visible cattle, what …

Photoelectric Injection Amplification Of Al–Al2o3–P-Cdte–Mo Structures At Low Bias Voltages, A K. Uteniyazov

Karakalpak Scientific Journal

The results of studies of photoelectric injection enhancement of the Al–Al₂O₃–p-CdTe –Mo structure upon application of low bias voltages. It has been shown that the studied Al-Al₂O₃–p-CdTe-Mo structure under can be represented as a n⁺-p-R_ом structure with a long base. Conducted researches show that Al-Al₂O₃–p-CdTe-Mo structure has unique properties. It has very high photocurrent and photosensitivity at both direct and reverse dias voltage under even small bias voltage (up to 500mV).

Synthesis Of Supramolecular Complex L– (-) – Menthol, Ziyada Djumanova Dr, Lolaxan Ettibaeva, Ugilay Abduraxmonova, Zulfiya Khalmuratova

Karakalpak Scientific Journal

In this article glycyrrhizic acid content with menthol in several various proportions (2:1; 4:1; 9:1), information was given on synthesis and physical and chemical properties of new supermolecular complexes. Received supramolecular complexes concerning 4:1 it was chemically defined and also studied the structure of supramolecular complexes by physical methods on the basis of interaction of organic molecules with electromagnetic radiation, in particular their range IR – of spectroscopy. Our work of the near future will be turned to check its recent supramolecular complexes on the basis of GA: Menthol for growth of a plant and biotic elasticity of tension …

Spectrophotometric Characterization Of The Complexation Of Gossypol Acetic Acid With Cobalt Ion, Ugilay Abdurahmanova, Habibjon Kushiev, Maral Askarova, Dilafruz Allanazarova

Karakalpak Scientific Journal

The authors of the article suggest simple and express method of spectrophotometric determination of cobalt with the help of derivatives of gossypol. Optimal conditions of determining cobalt are found. Under optimal conditions there was created a graded graph, which is more linear in the range for cobalt concentration of 10.0 – 50.0 microgram/25 ml, contents and constants of cobalt complex with gossypol vinegar acid.

Structural, Mineralogical And Quantitative Characterizations Of Compositions Of Products Linked To Explosive Volcanic Eruption At Haleakala, Usa, Aderemi Alabi, Ibukun Akinsola, Saminu Olatunji, Comfort Ogunyinka1, Oluwatoyin Osanyinlusi

Tanzania Journal of Science

This research focused the analysis vis-à-vis structural, mineralogical and quantitative characterizations of the samples which appeared to be formed from leftover of volcanic eruption sourced from basaltic magma obtained from Haleakala Hill, USA. The results show the presence of natural minerals like pyrolusite, zincite, magnetite, quartz, and diopside with their compositional concentrations in the samples. The geophysical analysis done corroborates the results obtained from the Scanning Electron Micrograph, which confirms the porosity of one of the samples. The X-Ray Diffraction results reveal the average grain sizes of the samples to range between 16 nm and 25 nm. Sample 'A' showed …

The Geochemical Compositions And Origin Of Sand Dunes In The Olduvai Gorge–Eastern Serengeti Plains, Northern Tanzania, Dalaly Kafumu

Tanzania Journal of Science

This paper reports the composition and origin of black sand dunes that occur in the eastern Serengeti plains near the Olduvai Gorge hominid site in Tanzania.  Grain size analysis reflected light microscopic examination, and scanning electron microscopy (SEM) analysis identified very fine to coarse sand fraction mineral grains of between 0.065 mm and 1 mm, composed of augite, fassaite and omphacite pyroxenes; garnet and sillimanite silicate mineral grains.  The pyroxene minerals (augite, omphacite and fassaite) constitute 95.4% by volume of the sand dunes. The other mineral grains are silicate minerals that include garnet and sillimanite, together form the remaining 4.6% …

Short Wavelength Infrared Spectral Characterization Of The Mineralogy Of Gokona And Nyabigena Andesite-Hosted Gold Deposits In North Mara, Tanzania, Emmanuel Kazimoto

Tanzania Journal of Science

The mineralogy of Gokona and Nyabigena gold deposits in Tanzania have been studied using Short Wavelength Infrared (SWIR) Spectrometry technique with an aim to fingerprint hydrothermal system responsible for the formation of the deposits and establish pertinent mineralogical signatures for gold deposition. Gokona and Nyabigena deposits are hosted in porphyritic andesite to basaltic andesite that contains plagioclase phenocrysts, pyroxene, hornblende and Fe-Ti oxides as primary minerals. Other minerals are actinolite, chlorite, epidote, albite and hematite, which indicate metamorphism of the rock under greenschist facies conditions. Hydrothermal alteration of the rock produced chlorite, sericite, carbonates (ankerite, siderite and calcite), pyrite and …

Preparation And Characterization Of Zns Thin Films Grown By Spin Coating Technique, Oluwatoyin Osanyinlusi

Tanzania Journal of Science

Spin coating technique was used to deposit zinc sulphide (ZnS) thin films successfully onto glass substrates and the effects of the number of spin times on the optical properties investigated. The morphology and structures of the prepared thin films were also confirmed. X-ray diffraction confirmed that spin coated ZnS films exhibited cubic structure, where reflections from (111), (220) and (311) are clearly visible with a preferential orientation along (111) plane. The calculated crystallite size for 1S sample from the XRD data is 8.8 nm. From the optical studies, the thin films exhibit good optical properties with relatively high transmittance (81 …

Geochemical Characteristics Of Soil In Relation To Occurrence Of Entomopathogenic Nematodes (Epns) In Osogbo, Osun State, Nigeria, Mohammed Rufai, Abidat Shittu, Monsuru Adeleke

Tanzania Journal of Science

The occurrence and abundance of entomopathogenic nematodes (EPNs) vary across locations, and this has been attributed to many factors including soil physico-chemical properties. This study examined the influence of selected soil chemicals on the occurrence of EPNs under different cultivated lands in Osun state, Southwestern Nigeria. EPNs were isolated from 23.33% of the soil samples in selected sites using decantation and centrifugation method and nematodes observed under standard microscopy were identified based on morphological analysis of infective juveniles (IJs). This study has revealed the presence of nematodes of the families Steinernema and Heterorhabditis in the sampled soils. Soil chemical properties, …

Stabilizing Capability Of Gum Arabic On The Synthesis Of Poly(Styrene-Methylmethacrylate-Acrylic Acid) Latex For The Generation Of Colloidal Crystal Films, Ikhazuagbe Ifijen, Stanley Omorogbe, Muniratu Maliki, Ifeanyi Odiachi, Aireguamen Aigbodion, Esther Ikhuoria

Tanzania Journal of Science

This article describes the generation and characterization of colloidal crystals from particles of gum arabic (GA) and sodium dodecylbenzene sulfate (SDBS) emulsified poly(styrene methylmethacrylate-acrylic acid) (P(St-MMA-AA) latex. The colloidal latex was synthesized using GA and SDBS as the emulsifying agents and then used to generate colloidal crystal films via the vertical deposition technique. Dynamic light scattering analysis placed the average particle diameter, polydispersity and Zeta potential at about 122 nm, 0.014 and –36.20 mV for the as-synthesized GA emulsified terpolymer latex and 213 nm, 0.006, –35.60 mV for the SDBS emulsified terpolymer latex, respectively. Thermo-gravimetric analysis and differential scanning calorimetry …

Construction Of Giant 2d And 3d Metallo-Supramolecules Based On Pyrylium Salts Chemistry, Yiming Li

USF Tampa Graduate Theses and Dissertations

Pyrylium salts are a type of six-membered cationic heterocycles with one positively charged oxygen atom. Since the discovery of pyrylium salts in 1911, such salts have been underappreciated for a long time. Until 1960s, the importance of pyrylium salts has been realized as versatile precursors in a variety of organic syntheses. Due to their high reactivity towards various nucleophiles, pyrylium salts were widely used for the convenient synthesis of diverse heterocyclic compounds. Starting from 1980s, the high reactive feature of pyrylium salts were further utilized to synthesize viologen polymers with pyridinium salts in the backbones. During the past two decades, …

Leaf Traits Can Be Used To Predict Rates Of Litter Decomposition, Marc Rosenfield, Jennifer L. Funk, Jason K. Keller, Catrina Clausen, Kimberlee Cyphers

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Strong relationships exist between litter chemistry traits and rates of litter decomposition. However, leaf traits are more commonly found in online trait databases than litter traits and fewer studies have examined how well leaf traits predict litter decomposition rates. Furthermore, while bulk leaf nitrogen (N) content is known to regulate litter decomposition, few studies have explored the importance of N biochemistry fractions, such as protein and amino acid concentration. Here, we decomposed green leaves and naturally senesced leaf litter of nine species representing a wide range of leaf functional traits. We evaluated the ability of traits associated with leaf and …

Thermal And Electrical Properties Of Isocyanate Derived Organic Aerogels For Cryogenic Insulation Applications, G. Churu, J. A. Demko, A. Mole, R. C. Duckworth, H. Lu, S. Malakooti, Nicholas Leventis

Chemistry Faculty Research & Creative Works

The use and storage of cryogens such as liquefied nitrogen, helium, hydrogen among others requires reliable and efficient thermal insulation systems. Passive insulation from high performance materials that are well-known for their inherent low thermal conductivity would reduce the overall costs involved in design, manufacture and maintenance of such systems. One such class of materials are referred to as aerogels. These materials are known for their low density, high mesoporosity, high surface areas, low thermal conductivity and high acoustic impedance. Aerogels were invented by S.S. Kistler in 1931, and the most common type are those made of silica. However, the …

Rapid Vertical Flow Assay On Aunp Plasmonic Paper For Sers-Based Point Of Need Diagnostics, Richard Frimpong

Theses and Dissertations

SERS based immunoassays for point-of-care diagnostics is a promising tool to facilitate biomarker detection for early disease diagnosis and control. The technique is based on a sandwiched system in which antigen is first captured by a selective substrate and then labeled by an extrinsic Raman label (ERL). Here, we report on the use of gold nanoparticle modified filter paper as a novel capture membrane in a vertical flow format. This vertical flow configuration affords reproducible flow of sample and label through the capture substrate to overcome diffusion limited kinetics and significantly reduced assay time. The filter paper was selected due …

The Interaction Of Ternary Components Of Ionic Liquid Gel Polymer Electrolytes For Lithium Metal Batteries, Xiao-Na Pan, Li-Lai Liu, Zhi-Pu Wang, Dan Wang, Yun Li, Pei-Xia Yang, Jin-Qiu Zhang, Mao-Zhong An

Journal of Electrochemistry

Ionically conductive gel polymer electrolyte is an excellent candidate due to its inflammable, nonvolatile and high thermal stability as compared to commercial liquid electrolytes which are usually flammable, volatile, and containing toxic organic solution as solvent, The synthesis and application of ionic gel polymer electrolytes in lithium ion/metal batteries have been previously reported. However, the interaction effects of N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13TFSI) ionic liquid (as plasticizer) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) on PVDF-HFP polymer remain unclear. In this work, the molecular structure of ionic liquid gel polymer electrolyte (ILGPE) composed of PP13TFSI, LiTFSI and PVDF-HFP was studied by Raman spectroscopy and Fourier-transform …

Electrochemical Oxidation Of Metal Chromium In Odium Hydroxide Aqueous Solution, Ping Han, Hai-Tao Feng, Ya-Ping Dong, Sen Tian, Bo Zhang, Wu Li

Journal of Electrochemistry

Ferrochrome electrolysis technology is a novel method for preparing sodium chromate (Na₂CrO₄). Although the method performs well at soft reaction conditions, controllable process, environmentally friendly production process, etc., the electrochemical oxidation process of metal chromium in NaOH aqueous electrolyte is still unclear. At present, there are few research articles about specific electrochemical oxidation of metal chromium in NaOH aqueous electrolyte. It is, therefore, meaningful to carry out the research in electrochemical oxidation mechanism of chromium. The electrochemical oxidation of metal chromium in 0.01 mol·L^-1 ~ 10 mol·L^-1 NaOH aqueous electrolytes at 20 °C was …

Ordered Mesoporous Carbon/Graphene/Nickel Foam For Flexible Dopamine Detection With Ultrahigh Sensitivity And Selectivity, Lai-Yu Wang, Xin Xi, Dong-Qing Wu, Xiong-Yu Liu, Wei Ji, Rui-Li Liu

Journal of Electrochemistry

Electro-catalytic reduction is an efficient way to achieve resourcable transformation of CO₂, which is one of the important techniques to solve the global environmental problems originated from excessive CO₂ emission. In this study, a membrane electrode assembly(MEA) type CO₂ electro-reduction electrolytic cell was constucted, which enables CO₂ feeding and real-time KHCO₃ aqueous updating on both sides of the cathode gas diffusion electrode (GDE). By means of the electrolytic cell, effects of KHCO₃ concentration and updating inside the liquid electrolytic chamber on CO₂ electro-reduction activity, production distribution and stability were investigated. The experimental …

Poly(Ethylene Oxide) Based Polymer Electrolytes For All-Solid-State Li-S Batteries, Xue Li, Zheng-Liang Gong

Journal of Electrochemistry

In recent years, research on lithium-sulfur (Li-S) batteries has received much attention because the sulfur positive electrode and the lithium metal negative electrode produce a high theoretical specific capacity (lithium metal ~ 3800 mAh·g^-1, sulfur ~ 1675 mAh·g^-1). In addition, sulfur is considered to be the most promising cathode material for secondary lithium batteries, due to its advantages of low price and environmental friendly. However, the practical application of conventional liquid Li-S batteries is still obstructed by several critical issues, such as lithium ploysulfides shuttle effect, long-term stability of lithium metal anode with organic liquid electrolytes, …

Electrochemical Response Of A Single Wire-Electrode Ac Probe In 3.5wt.% Nacl, Zhen-Wen Zou, Da-Jiang Zheng, Zi-Ming Wang, Guang-Ling Song

Journal of Electrochemistry

In this paper, a recently developed single wire-electrode AC probe technology which does not need a reference or counter electrode was employed to investigate the electrochemical corrosion and sacrificial anode protection behaviors of steel and zinc in 3.5wt.% NaCl. With this simple, fast, reliable and stable probe, the instantaneous corrosion rate and accumulated corrosion loss of carbon steel in 3.5wt.% NaCl were measured, and the results revealed that both were greater than those of zinc. Furthermore, the observed different corrosion behaviors between carbon steel and zinc during the immersion could be caused by their different surface films. With the galvanic …