Physical Sciences and Mathematics Commons^™

Identification Of Arabidopsis Gpat9 (At5g60620) As An Essential Gene Involved In Triacylglycerol Biosynthesis, Jay Shockey, Anushobha Regmi, Kimberly Cotton, Neil Adhikari, John Bowse, Philip D. Bates

Faculty Publications

The first step in the biosynthesis of nearly all plant membrane phospholipids and storage triacylglycerols is catalyzed by a glycerol-3-phosphate acyltransferase (GPAT). The requirement for an endoplasmic reticulum (ER)-localized GPAT for both of these critical metabolic pathways was recognized more than 60 years ago. However, identification of the gene(s) encoding this GPAT activity has remained elusive. Here, we present the results of a series of in vivo, in vitro, and in silico experiments in Arabidopsis (Arabidopsis thaliana) designed to assign this essential function to AtGPAT9. This gene has been highly conserved throughout evolution and is …

Kohn–Sham Exchange-Correlation Potentials From Second-Order Reduced Density Matrices, Rogelio Cuevas-Saavedra, Paul W. Ayers, Viktor N. Staroverov

Chemistry Publications

We describe a practical algorithm for constructing the Kohn–Sham exchange-correlation potential corresponding to a given second-order reduced density matrix. Unlike conventional Kohn–Sham inversion methods in which such potentials are extracted from ground-state electron densities, the proposed technique delivers unambiguous results in finite basis sets. The approach can also be used to separate approximately the exchange and correlation potentials for a many-electron system for which the reduced density matrix is known. The algorithm is implemented for configuration-interaction wave functions and its performance is illustrated with numerical examples.

Synthesis Of Porous Carbon Nanosheets And Its Application In Sodium-Ion Battery, Jing-Fei Zhang, Jing Lu, Xiao-Yu Yang, Yun-Di Huang, Lin Xu, Dong-Mei Sun, Ya-Wen Tang

Journal of Electrochemistry

Owning to sodium’s high abundance, relatively low cost, similar chemical properties to Li and very suitable redox potential of E0(Na+/Na) = -2.71 V versus SHE which is only 0.3 V above that of lithium, rechargeable sodium ion battery hold much promise as potential alternatives to current lithium ion batteries for energy storage applications. Carbon material is regarded as the most promising anode candidate for sodium ion battery. Particularly, carbon nanosheet with porous structure and high conductivity is expected to have improved sodium ion storage properties. In this paper, we present a two-step pyrolysis-based method for facile synthesis of porous carbon …

Carbon Aerogel/Nickel Foam As Electrode For High-Performance Supercapacitor, Zhong Wu, Xin-Bo Zhang

Journal of Electrochemistry

Herein, a facile synthesis has been explored to prepare carbon aerogel/Ni foam. Graphene oxide, resorcinol and formaldehyde serve as precursors and polymerize in-situ on the Ni foam after hydrothermal synthesis at 85 oC. After lyophilization treatment, the carbon aerogel/Ni foam with porous structure can be obtained. Electrochemical investigations reveal that the carbon aerogel/Ni foam exhibits superior performances in both aqueous and organic electrolytes involving high specific capacitance and long-term cycling stability. The excellent properties can be ascribed to the unique formation and porous structure, which allows more effective transportations of electron and electrolyte ion.

Intercalation Of Clo4- Into Hopg Investigated By Ec-Stm, Xiao-Yan Hu, Alice Aliwowe, Jia-Wei Yan, Bing-Wei Mao

Journal of Electrochemistry

The electrochemical intercalation and surface morphology of highly oriented pyrolytic graphite (HOPG) electrode in 2 mol•L^-1 HClO₄ were studied by in situ scanning tunneling microscopy (STM) and cyclic voltammetry (CV). Based on the step-height changes observed before and after the intercalation, the effects of different step sites on intercalation are compared. The feasibility, reversibility and speed of intercalation are discussed. The intercalation of ClO₄^- into HOPG can be divided into three types depending on the number of graphite layers at the step site: When the layers of graphite are more than three, the intercalation becomes feasible; …

Effect Of Mno2 Content On Electrochemical Capacitance Behavior Of Active Carbon Electrode, Kun Shen, Xian-Liang Zhou, Qi-Shun Duan

Journal of Electrochemistry

In this work, the manganese dioxide (MnO₂) materials were prepared by solution approach at low temperature, thermal decomposition and electrochemical deposition. The actived carbon (AC) and MnO₂ composite electrodes were used for aqueous supercapacitors. The morphologies and structures of the prepared materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the electrochemical behaviors were tested by cyclic voltammetry (CV) and galanostatic charge-discharge tests. Electrochemical test data show that the maximum specific capacitances of 151, 172 and 141 F•g^-1 were obtained with the contents of MnO₂ being 70, 60 and 70% in …

Fast And Accurate Evaluation Of Lifepo4 Cathode Materials By Single Particle Microelectrode, Fu-Qing Wang, Yi-Min Wei, Yu-Zhuan Su, Bing-Wei Mao, Kai Wu, Feng-Gang Zhao, Chun-Lei Chen, Xing-Lu Li, Jin Chong

Journal of Electrochemistry

Single particle microelectrode enables to evaluate the electrochemical responses for single particle of active material without binder and conductive agent. Thus, the influences of additive and electrode structure on the electrochemical performance of active materials can be ignored. Furthermore, this technology can be used to evaluate active materials fast. Therefore, single particle microelectrode allows fast and accurate determination of the intrinsic performance of active material. Cyclic voltammogram (CV), cycle performance, and kinetic behavior of LiFePO4 cathode materials were evaluated by the single particle microelectrode. CV curve of LiFePO4 particle with a pair of oxidation and reduction peaks was obtained with …

Special Issue: Electrochemistry Of Carbon Materials, Chen Wei

Journal of Electrochemistry

Carbon materials are traditional electrode materials due to their excellent electrical conductivities, high electrochemical stabilities and wide potential windows. Glassy carbon, graphite, various activated charcoals, carbon fibers etc. have been widely used in electrochemistry serving as electrode substrates or supports. In addition to their applications in basic electrochemistry, carbon materials have also played important roles in electrochemical energy storage and conversion. In recent years, various types of carbon structures, from zero-dimensional carbon nanodots, one-dimensional nanotubes, two-dimensional graphene to three-dimensional porous carbons, have attracted increasing attention in electrochemical field. It has been found that carbon materials have outstanding properties as advanced …

Applications Of Carbon Materials In Electrochemical Energy Storage, Ji Liang, Lei Wen, Hui-Ming Cheng, Feng Li

Journal of Electrochemistry

An electrode material for electrochemical energy storage is one of the key components for high performance devices. In a variety of electrochemical energy storage systems, carbon materials, especially the lately emerged carbon nanomaterials including the carbon nanotube and graphene, have been playing a very important role and brought new vitality to the development and demonstration of the broad application prospects. In this review, we summarize the applications of various carbon materials in the typical electrochemical energy storage devices, namely lithium/sodium ion batteries, supercapacitors, and lithium-sulfur batteries, as well as flexible electrochemical energy storage and electrochemical catalysis. A perspective of novel …

Colloidal Ionic Supercapacitors, Kun-Feng Chen, Dong-Feng Xue

Journal of Electrochemistry

Supercapacitors have high power density and long cycle life compared with battery systems, but they still suffer from low energy density at the same time. In order to increase the energy density of supercapacitors, we have developed a new type of pseudocapacitor, called colloidal ion supercapacitor, which can directly use commercial metal salts as electrode materials and form electroactive matter by in-situ electrochemical reactions without the need of additional materials synthesis processes. Colloidal ion supercapacitor can fully utilize the redox reaction of metal cations with multiple oxidation states, which can completely release the stored electrical energy of multiple-valence cations, leading …

Progress Of Self-Supported Supercapacitor Electrode Materials Based On Carbon Substrates, Shui-Jian He, Wei Chen

Journal of Electrochemistry

Self-supported electrode materials have been widely used in supercapacitors. Carbon materials are promising substrates in building self-supported electrode materials attributed to their diverse structures, rich resource, relatively low cost and high stability. Combined with our own research in this field, we summarize here the recent progress on the synthesis of self-supported electrode materials and their supercapacitance properties. The overall synthetic strategy could be divided into two categories: “top-down” and “bottom-up”. We hope this review is helpful for the development and application of renewable sources in self-supported electrode materials.

Electrodeposition Of Lanthanum In Deep Eutectic Solvents, Li Wang, You-Jun Fan, Lu Wei, Hai-Xia Liu, Shi-Gang Sun

Journal of Electrochemistry

With the choline chloride/urea deep eutectic solvents (DESs) as the medium, the olive-like lanthanum particles with uniform shape and size were successfully prepared through a potentiostatic deposition method. The prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS). At the same time, the effect of deposition potential, temperature and time on the size and morphology of samples was investigated. The results demonstrated that the optimum conditions for the preparation of olive-like lanthanum particles were as follows: deposition potential of -1.7 V, temperature of 80 ^oC …

Electrochemical Properties Of Graphene/Porous Nano-Silicon Anode, Chun-Li Li, Guang Yang, Ping Zhang, Zhi-Yu Jiang

Journal of Electrochemistry

Porous nano-silicon (Si) was prepared by acid etching Al-Si alloy powder method, and used as an active material for fabricating a grapene/porous nano-Si electrode. The results of SEM and TEM measurements indicated that porous nano-Si powder was uniformly mixed with graphene by emulsification dispersion-ultrasonication method. As an anode for lithium ion battery, the graphene/porous nano-Si electrode presented relatively high performance in 1 mol•L^-1 LiPF6/EC:DMC = 1:1(by volume) + 1.5% (by mass) VC solution. At the charge and discharge current densities of 0.5A•g^-1, the first discharge capacity was 1768.6 mAh•g^-1 with coulombic efficiency of 68.3%. The discharge …

Characterization Of Cytidylyltransferase Enzyme Activity Through High Performance Liquid Chromatography, James Brault

Theses and Dissertations

The cytidylyltransferases are a family of enzymes that utilize cytidine 5â?? triphosphate (CTP) to synthesize molecules that are precursors to membrane phospholipids. There are four well known enzymes: CTP: phosphoethanolamine cytidylyltransferase (ECT), CTP: glycerol-3-phosphate cytidylyltransferase (GCT), 2-C-methyl-D-erythritol-4-phosphate cytidylyltransferase synthetase (CMS), and CTP: phosphocholine cytidylyltransferase (CCT). Previously, a radioisotope tagging method was employed to study cytidylyltransferase catalysis. Using CCT as a model, a method utilizing high performance liquid chromatography (HPLC) was developed to replace the radioisotope scintillation technique. The development of this new HPLC method is cheaper, more efficient, and more accurate than the previously established method.

The targets of separation …

Self-Assembling Biomolecular Catalysts For Hydrogen Production, Dustin Patterson

Dustin Patterson

Bodipy-Based Fluorescent Probes For Sensing Protein Surface-Hydrophobicity, Nethaniah Dorh, Shilei Zhu, Kamal B. Dhungana, Ranjit Pati, Fen-Tair Luo, Haiying Liu, Ashutosh Tiwari

Department of Chemistry Publications

Mapping surface hydrophobic interactions in proteins is key to understanding molecular recognition, biological functions, and is central to many protein misfolding diseases. Herein, we report synthesis and application of new BODIPY-based hydrophobic sensors (HPsensors) that are stable and highly fluorescent for pH values ranging from 7.0 to 9.0. Surface hydrophobic measurements of proteins (BSA, apomyoglobin, and myoglobin) by these HPsensors display much stronger signal compared to 8-anilino-1-naphthalene sulfonic acid (ANS), a commonly used hydrophobic probe; HPsensors show a 10- to 60-fold increase in signal strength for the BSA protein with affinity in the nanomolar range. This suggests that these HPsensors …

Photooxidation Reactions Of Small-Chain Methyl Esters, Aerosol Photoelectron Spectroscopy, And The Photodissociation Of Ethylenediamine, Giel Muller

Master's Theses

Research conducted at the University of San Francisco is presented within this masters thesis, including the Cl-initiated photooxidation reactions of methyl propanoate, methyl butanoate, and methyl valerate (pentanoate), the aerosol photoelectron spectroscopy of isoprene and gamma-valerolactone, and the TPEPICO investigation of ethylenediamine. Experiments were conducted at the Lawrence Berkeley National Lab Advanced Light Source (ALS), the National Synchrotron Radiation Research Center in Hsinchu City (NSRRC), and the University of Stockton in California, respectively.

Antiviral Peptide Nanocomplexes As Potential Therapeutics For The Treatment Of Infectious Diseases, Jinjin Zhang

Theses & Dissertations

Hepatitis C Virus (HCV) is recognized as a major burden in global public health, which can be further exacerbated by several cofactors such as human immunodeficiency virus (HIV). Currently, there is no vaccine for HCV. The emergence of potent and highly specific direct-acting antivirals (DAA) has marked a new era in HCV therapy, however, the remaining issues like affordability, genotype dependency, and potential resistance still necessitate the development of additional therapeutic approaches to be used instead or in combination with DAA.

Recently, the antiviral peptide C5A (in our studies designated as p1) and its cationic derivative p41 have been identified …

Microsolvation Of Anions By Molecules Forming Ch∙∙X- Hydrogen Bonds, Steve Scheiner, Binod Nepal

Chemistry and Biochemistry Faculty Publications

Various anions were surrounded by n molecules of CF₃H, which was used as a prototype CH donor solvent, and the structures and energies studied by M06-2X calculations with a 6-31+G∗∗ basis set. Anions considered included the halides F^-, Cl^-, Br^- and I^-, as well as those with multiple proton acceptor sites: CN^-, NO₃ ^-, HCOO^-, CH₃COO^-, HSO₄ ^-, H₂PO₄ ^-, and anions with higher charges SO₄ ^2-, HPO₄ ^2- and PO_{4 …}

Designing Synthetic Pathways For Several 2-Thio-Substituted-3h-Phenothiazin-3-Ones In Preparation For Testing In Treatment Of Central Nervous System Disorders, Preston H. Palm, Herman H. Odens

Senior Research Projects

This paper investigates possible synthetic pathways for two 2-thio-substituted-3H-phenothiazin-3-ones (7). A two step reaction in which 1,4-benzoquinone (1) is first reacted with an alkylthiol (2) in the presence of sodium periodate (NaIO₄) and then treated with 2-aminothiophenol (5) followed by a second oxidation with sodium periodate was demonstrated to be effective in synthesizing 2-(phenylthio)-3H-phenothiazin-3-one (12). The same synthetic approach was shown to be ineffective in the synthesis of 2-(cyclopentylthio)-3H-phenothiazin-3-one (16) due to the fact that the first step was incapable of synthesizing 2-(cyclopentylthio)-1,4-benzoquinone (14). Several other synthetic routes were also proven to be ineffective. This …

Investigation Of 89zr-Siderophores As Molecular Imaging Agents For Positron Emission Tomography Imaging Of Bacterial Infections, Nora C. M. Goscinski

Arts & Sciences Electronic Theses and Dissertations

Siderophores are small molecules synthesized by bacteria to harvest Fe³⁺ from their environment. In infection scenarios, their production can increase infection virulence by increasing the ability of bacteria to obtain Fe³⁺ and therefore grow more rapidly. The selective uptake of siderophores in vivo in multi-bacteria environments indicates that this class of molecules has a potential use as selective imaging agents. In this work, DFO-NCS and a library of trihydroxamate siderophores were evaluated as vehicles to deliver ⁸⁹Zr selectively to bacteria for Positron Emission Tomography (PET) imaging of bacterial infections.

Productive work with radiometals involves thorough knowledge of …

Applying Bayesian Machine Learning Methods To Theoretical Surface Science, Shane Carr

McKelvey School of Engineering Theses & Dissertations

Machine learning is a rapidly evolving field in computer science with increasingly many applications to other domains. In this thesis, I present a Bayesian machine learning approach to solving a problem in theoretical surface science: calculating the preferred active site on a catalyst surface for a given adsorbate molecule. I formulate the problem as a low-dimensional objective function. I show how the objective function can be approximated into a certain confidence interval using just one iteration of the self-consistent field (SCF) loop in density functional theory (DFT). I then use Bayesian optimization to perform a global search for the solution. …

Optical-Optical Double Resonance, Laser Induced Fluorescence, And Revision Of The Signs Of The Spin-Spin Constants Of The Boron Carbide (Bc) Free Radical, Fumie X. Sunahori, Ramya Nagarajan, Dennis J. Clouthier

Chemistry Faculty Publications

The cold boroncarbide free radical (BC X  ⁴Σ⁻) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescencespectra have been obtained for the B  ⁴Σ⁻–X  ⁴Σ⁻ and E  ⁴Π–X  ⁴Σ⁻ band systems of both ¹¹BC and ¹⁰BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then …

Hydroxy Polybenzimidazoles For High Temperature Fuel Cells And The Solution Polymerization Of Polybenzimidazole, Kayley Fishel

Theses and Dissertations

In this dissertation, two different hompolymers of polybenzimidazole (PBI) containing hydroxyl functional units were synthesized via the PPA Process to produce gel membranes. These polymers and their phosphoric acid doped membranes were characterized to further explore structure-property relationships in functionalized PBI's. Fuel cell performance of the doped membranes was evaluated and compared to previously reported PBI membrane chemistries. Copolymers of p-OH PBI and para-PBI were prepared at five different copolymer compositions to examine the effects of hydroxy content on membrane properties and compared to the respective homopolymers. The reactivity of the hydroxy groups and the formation of phosphate bridges were …

Defining The Effects Of Gdf-2 On TgfB Signaling In Tumorigenic Epithelial Cells, Tirthankar Bandyopadhyay

Theses and Dissertations

Cancer cells can be viewed as such cells, which have disrupted/aberrant signaling pathways for maintaining cellular homoeostasis. Identifying such altered signaling mechanisms can help us target these pathways in a better way. GDF-2 (Growth and differentiation factor – 2) or BMP9 (Bone morphogenetic protein – 9), a multifunctional cytokine, is a member of the Bone Morphogenetic Protein subfamily, under TGFβ superfamily, with roles distinct from BMP2/4/7. While GDF-2 is known to be one of the most potent ectopic inducers of bone and cartilage formation, it rose to significance with the identification of its receptor ALK1 in endothelial cells. TGFβ’s role …

Supramolecular Coordination Networks Of S- And F-Block Metals Featuring The 1,8-Naphthalimide Tecton, Andrew Paul Leitner

Theses and Dissertations

The reactions of (S)-2-(1,8-naphthalimido)propanoic acid (HLala), and (S)-2-(1,8- naphthalimido)-3-hydroxypropanoic acid (HLser), protonated forms of ligands that contain a carboxylate donor group, an enantiopure chiral center and a 1,8-naphthalimide π...π stacking supramolecular tecton and in the case of HLser an alcohol functional group, with the appropriate alkali metal hydroxide followed by a variety of crystallization methods leads to the formation of crystalline K(Lala)(MeOH) (1), K(Lala)(H2O) (2), Na(Lala)(H2O) (3), KLser (4), CsLser (5) and CsLala (6). Each of these new complexes has a solid state structure based on six-coordinate metals linked into homochiral helical rod SBU central cores. In addition to the …

Optimized Spectral Processing Of Infrared Diffuse Reflection Spectra For The Detection Of Blood On Fabric, Stephanie Ann Dejong

Theses and Dissertations

The detection of bodily fluids such as blood on interfering backgrounds is important to the forensic community. Luminol, which participates in a chemiluminescent reaction with the heme groups of blood, is one of the most commonly used presumptive tests. Luminol has a few drawbacks, including the requirement of use in a dark environment and potential to degrade the amount of recoverable DNA in blood stains. A potential complementary method is infrared (IR) spectroscopy. These two methods are compared in this work. Infrared diffuse reflection (DR) spectroscopy works well to measure the IR spectrum of samples that are highly absorbing or …

Two-Dimensional Transient Spectroscopy Measuring Heterogeneity In Electronic And Rotational Dynamics, Haorui Wu

Theses and Dissertations

Multiple population-period transient spectroscopy (MUPPETS) is a picosecond, time resolved experiment that uses a sequence of six laser pulses. It was previously known that MUPPETS could measure heterogeneity in electronic-state decay. This dissertation presents two projects that extend MUPPETS to new processes. One process is the extension from 2-level system into 3-level system, another new process extends the kinetics from electronic decay to rotational decay. In addition, a third, ongoing project on rotational dynamics in ionic liquids will also be discussed briefly. The first project consisted of two main parts. The first part focused on the biexciton decay in semiconductor …

Optimization Of Shell Growth And Influence Of Surface Ligands For Colloidal Cdse/Cds Core/Shell Quantum Dots, Rui Tan

Theses and Dissertations

Progress in the colloidal synthesis of semiconductor quantum dots (QDs) has triggered a burst of research toward applications in QD based light emitting diodes, biological imaging as fluorescent tags, and advanced solar cell designs. In order to adjust and optimize the photo physical properties of QDs, QD heterostructures have been introduced and widely explored. This dissertation is focused on studies of growth of semiconductor colloidal CdSe/CdS core/shell quantum dots and the influences of neutral surface ligands to their photo-physical properties. Chapter 1 provides an introduction of the concept of semiconductor colloidal nanoparticles, core/shell heterostructures and the synthesis methods as well …

Applications Of Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy For Forensic Analysis, Zhenyu Lu

Theses and Dissertations

Blood stains, which are among the traces encountered most frequently at crime scenes, are important for potential extraction and amplification of DNA for suspect identification, as well for spatter pattern analysis to reveal a sequence of events. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used in detection of blood stains and age estimation because of signature absorbances in the mid-infrared region at 3300 cm-1 (Amide A), 2800-3000 cm-1 (Amide B), ~1650 cm-1 (Amide I), ~1540 cm-1 (Amide II) ,and 1200-1350 cm-1 (Amide III). Position and intensity shifts for amide peaks were observed due to aging changes occurring as …