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2011

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Articles 361 - 390 of 1068

Full-Text Articles in Chemistry

Research Progress In Orthosilicates As Cathode Materials For Li-Ion Batteries, Dong-Ping Lv, Lin Wang, Yong Yang May 2011

Research Progress In Orthosilicates As Cathode Materials For Li-Ion Batteries, Dong-Ping Lv, Lin Wang, Yong Yang

Journal of Electrochemistry

Rechargeable Li-ion batteries fulfilling high-energy density, high safety, environmental friendliness, and low cost are demanded urgently for energy storage systems. Besides the structure stability arising from the strong Si-O covalent bond, environmental benignancy and low cost from the characteristics of Fe, Mn, Si elementals, orthosilicates (Li2MSiO4) show promising prospect to meet the demand of high-energy density for its two available Li+ per formula unit. Motivated by these significant advantages, Li2MSiO4 have been intensively investigated in the past few years. In the present work, we gave a review on the progress of orthosilicate research …

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Effect Of Pore Size On Pseudo-Capacitive Performance Of Nio In The Mixed Electrolyte Of Koh And Hexacyanoferrate, Wen Wu, Meng-Yan Hou, Dan-Dan Zhou, Yong-Yao Xia May 2011

Effect Of Pore Size On Pseudo-Capacitive Performance Of Nio In The Mixed Electrolyte Of Koh And Hexacyanoferrate, Wen Wu, Meng-Yan Hou, Dan-Dan Zhou, Yong-Yao Xia

Journal of Electrochemistry

In this paper, five kinds of NiO samples with different pore size distributions were synthesized .The electrochemical capacitance of the samples were characterized in 3 mol/L KOH solution with and without hexacyanoferrate addition. Electrochemical test results indicated the NiO sample with an optimum pore size of about 15 nm shows high Coulombic efficiency of the N4(NiO) electrode as the redox reaction of hexacyanoferrate ions would be limited in the pore, thus prevent ion diffusion into the bulk electrolyte solution .

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Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan May 2011

Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan

Journal of Electrochemistry

A simple and efficient electrochemical route was developed for the synthesis of flaked spindle-like CuO nanocrystals using aqueous electrolyte and Cu sacrificial anode (graphite as the cathode) in an undivided cell at a constant potential mode under room temperature. The morphologies, structure and component of CuO nanocrystals obtained were characterized by SEM, XRD, respectively. Flaked spindle-like CuO nanocrystals were successfully used to modify a GC electrode to detect H2O2 with cyclic voltammetry (CV) and amperometric (AC).The results showed that products were pure monoclinic CuO nanocrystals. The linear range for the determination of hydrogen peroxide is from 1.0 …

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Investigation Of Supercapacitors Based On Polyvinyl Alcohol Hydrogel-Polymer Electrolyte, Kai-Qing Xu, Le-Qing Fan, Ji-Huai Wu, Qing Leng, Xin Zhong, Jian-Ming Lin, Miao-Liang Huang, Zhang Lan May 2011

Investigation Of Supercapacitors Based On Polyvinyl Alcohol Hydrogel-Polymer Electrolyte, Kai-Qing Xu, Le-Qing Fan, Ji-Huai Wu, Qing Leng, Xin Zhong, Jian-Ming Lin, Miao-Liang Huang, Zhang Lan

Journal of Electrochemistry

For the first time, the supercapacitor based on the hydrogel-polymer electrolyte which consisted of the cross-linking of polyvinyl alcohol-glutaraldehyde (PVA-GA) using 2-acrylamido-2-methyl propane sulfonic acid (AMPS) as solicitation reagent was assembled. The gel polymer electrolyte was characterized by FTIR and AC impedance. The maximum ionic conductivity is 1.23 mS/cm at room temperature. The electrochemical properties of the supercapacitor were investigated by cyclic voltammetry, AC impedance spectra and constant current charge-discharge curve. The results show that the specific capacitance reachs 139 F/g with AMPS of 1.0 g and 0.05 mL of 5 %(by mass) GA. And the specific capacitance still retained …

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Detection Of Acute Promyelocytic Leukemia Pml/Rarî± Fusion Gene Using Graphene Modified Glassy Carbon Electrode, Zhi-Xian Lian, Guang-Xian Zhong, Kun Wang, Ai-Lin Liu, Xin-Hua Lin, Yuan-Zhong Chen May 2011

Detection Of Acute Promyelocytic Leukemia Pml/Rarî± Fusion Gene Using Graphene Modified Glassy Carbon Electrode, Zhi-Xian Lian, Guang-Xian Zhong, Kun Wang, Ai-Lin Liu, Xin-Hua Lin, Yuan-Zhong Chen

Journal of Electrochemistry

A graphene modified glassy carbon electrode (GCE) was prepared by electrochemical reduction of graphite oxide fixed on the surface of GCE. Then, the amino-group modified probe of acute promyelocytic leukemia (APL) PML/RARα fusion gene fragment was immobilized onto surface of the graphene modified GCE by coupling activating agent. With methylene blue (MB) as a novel electrochemical indicator, artificial APL PML/RARα fusion gene fragment was measured by differential pulse voltammetry (DPV). The result indicated graphene nanomaterial showed good sensitization on the signal of MB. The relationship between the reduction peak current of MB and the concentration of complementary strand was linear …

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Study On Direct Electro-Oxidation Of Anisaldehyde, Lin-Lin Wu, Ying-Hong Zhu, Shan-Shan Li, Hong-Yan Zeng, Chun-An Ma May 2011

Study On Direct Electro-Oxidation Of Anisaldehyde, Lin-Lin Wu, Ying-Hong Zhu, Shan-Shan Li, Hong-Yan Zeng, Chun-An Ma

Journal of Electrochemistry

The oxidation of anisole on Pt electrode was investigated by cyclic voltammery and constant potential electrolysis. The influence of scan rates, substrate concentration, supporting electrolytes and solvent were considered . The results show that the electro-oxidation process of anisole was irreversible. In this research the sulfuric acid was the best supporting electrolytes and acetone was the best solvent, and the process was controlled by diffusion . The product of constant potential electrolysis was charactered by GC-MS .The results show that the main products was anisaldehyde, and the selectivity was up to 66.5% when using acetone as solvent.

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Electric Vehicles And Power Batteries, Xin-Ping Ai, Han-Xi Yang May 2011

Electric Vehicles And Power Batteries, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

In retrospect of the historical development of Electric Vehicles (EV), the impact of battery technologies on the progress of EV was discussed. In consequence, it is concluded that the lack of advanced batteries was the main cause for the fluctuations of EV development and the sluggish commercialization of electric cars in the past century. After a brief introduction to the classification and the requirements of electric vehicles, the main issues of the batteries including safety, temperature range for operation and the cost as well as the effects of these factors on the applications of advanced batteries for electric vehicles were …

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Effects Of Additives On The Electrochemical Behaviors Of Zn Electrode In Alkaline Solutions, Shu-Na Hong, Hai-Bin Lin, Zuo-Jian Su, He-Bing Zhou, Man Liang, Wei-Shan Li May 2011

Effects Of Additives On The Electrochemical Behaviors Of Zn Electrode In Alkaline Solutions, Shu-Na Hong, Hai-Bin Lin, Zuo-Jian Su, He-Bing Zhou, Man Liang, Wei-Shan Li

Journal of Electrochemistry

Electrochemical behaviors of Zn in 3mol⋅L-1 KOH solution containing the single additive(Pb(NO3)2, SDBS) the mixed additives(Pb(NO3)2+SDBS) were investigated. The results showed that all the additives can supress the corrosion of zinc in 3mol•L-1 KOH solution. And the inhibition effeciency of the mixed additives is higher than that of any single additive.

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Anode Electrodeposition Of Ti/Mno2 Electrode And Electrocatalytic Oxidization Properties Of Phenol Degradation, Ye Chen, Wen-Li Zhao, Qing Wen May 2011

Anode Electrodeposition Of Ti/Mno2 Electrode And Electrocatalytic Oxidization Properties Of Phenol Degradation, Ye Chen, Wen-Li Zhao, Qing Wen

Journal of Electrochemistry

Ti-base manganese dioxide (Ti/MnO2) electrode was prepared by anodically electrodeposition technology in this paper. The structure of the electrode, the microstructure of the electrode surface and the element composition of the electrode were analyzed by XRD, SEM and EDS. The preparation process parameters of the electrode were studied in detail with the help of the V~logi curve and phenol degradation curve. The Ti/MnO2 electrode was anodically electrodeposited at current density 4mA•cm-2, the Mn2 + ions concentration 0.5mol•L-1 and temperature70℃. The V~logi curve and phenol degradation curve were used to evaluate electrocatalytic oxidization properties …

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Capacitance Behaviors Of Ti/Ru0.1Ti0.1Sn0.8O2 Electrodes, Hai-Yan Chen, Yan-Qun Shao, Dian Tang May 2011

Capacitance Behaviors Of Ti/Ru0.1Ti0.1Sn0.8O2 Electrodes, Hai-Yan Chen, Yan-Qun Shao, Dian Tang

Journal of Electrochemistry

Ti/Ru0.1Ti0.1Sn0.8O2 electrodes were prepared by low temperature thermal decomposition. The structural characteristics were analyzed by X-ray diffraction(XRD).The performances were tested by cyclic voltammetry and constant current charge-discharge measurements. The results show that, the structure of Ti/Ru0.1Ti0.1Sn0.8O2 belongs to small rutile phase. A high specific capacitance of 933F/g is obtained at scan rate of 20 mV/s. The cycle life test shows a 23.6% specific capacitance lost after 1000 cycles. The electrode has a good cycle stability and reversibility.

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Electroless Silver Plating On The Cotton Fiber Modified With 3-Mercaptopropyltriethoxysilane, Li-Li Li, Wei Wang May 2011

Electroless Silver Plating On The Cotton Fiber Modified With 3-Mercaptopropyltriethoxysilane, Li-Li Li, Wei Wang

Journal of Electrochemistry

This paper studies on the characteristics of the electroless silver plating cotton fiber modified with 3-mercaptopropyltriethoxysilane.The effects of each factors on surface resistance and rate of weight gain was tested by the method of orthogonal test. It is concluded that the optimal technology for preparing the silver plating cotton fiber:concentration of the 3-mercaptopropyltriethoxysilane 1%, modification time 120min, the bath ratio of modification 1:60,dosage of AgNO3 3.5g, dosage of C6H12O6 3.5g, plating temperature 50℃, plating time 60min. SEM and XRD analysis shows that the silver plating on the cotton fiber modified with mercapto is uniform …

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The Flip-Flop Behavior Of Acetonitrile At Au Electrode Surface Investigated By Sum Frequency Generation Vibrational Spectroscopy, Zhi Huang, Xin Tang, Gang-Hua Deng, En-Cai Zhou, Hong-Fei Wang, Yuan Guo May 2011

The Flip-Flop Behavior Of Acetonitrile At Au Electrode Surface Investigated By Sum Frequency Generation Vibrational Spectroscopy, Zhi Huang, Xin Tang, Gang-Hua Deng, En-Cai Zhou, Hong-Fei Wang, Yuan Guo

Journal of Electrochemistry

The electrochemical interface between liquid acetonitrile and polycrystal gold electrode is investigated by in situ infrared visible sum frequency generation spectroscopy (SFG-VS). The structure of acetonitrile adsorbed at polycrystal gold electrode surface is studied as a function of electrode potential. The SFG spectra of CH3 group indicate acetonitrile orients in response to the electrode potential. The SFG signal of CH3 group turns lower as the electrode potential changes from -700mV to 300mV, and vanishes around the 300mV(pzc), then becomes a negative signal above 500mV, which indicates that the orientation is predominately with the CH3 group toward the …

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Preparation And Performance Of Carbon-Coated Si/C Composites, Li-Li Du, Quan-Chao Zhuang, Tao Wei, Yong-Li Cui, Zhi Sun, Shi-Gang Sun May 2011

Preparation And Performance Of Carbon-Coated Si/C Composites, Li-Li Du, Quan-Chao Zhuang, Tao Wei, Yong-Li Cui, Zhi Sun, Shi-Gang Sun

Journal of Electrochemistry

Si/C composite for lithium ion batteries was obtained by pyrolyzing and ball-milling. The microstructure and component of the composite was characterized by SEM and XRD, the electrochemical performance was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvano static charge-discharge tests. The results illustrate that the particle of Si/C composite prepared by pyrolysis exhibits inerratic morphology, uniform carbon-coating layer, good electrical conductivity, low resistance. The first intercalated-lithium capacity of the composite material is 4495 mAh/g; the first coulomb efficiency is 65.3%. From the second week the coulomb efficiency maintains 97%, and the capacity at the 100th cycle can …

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Hairpin Locked Nucleic Acids Probe Based Electrochemical Biosensor For Detection Of Bcr/Abl Fusion Gene, Hong-Mei Wang, Li-Qing Lin, Shao-Huang Weng, Li-Man Wang, Yin-Huan Liu, Xin-Hua Lin May 2011

Hairpin Locked Nucleic Acids Probe Based Electrochemical Biosensor For Detection Of Bcr/Abl Fusion Gene, Hong-Mei Wang, Li-Qing Lin, Shao-Huang Weng, Li-Man Wang, Yin-Huan Liu, Xin-Hua Lin

Journal of Electrochemistry

In this article, a new kind of structure hairpin LNA probe was designed to detect BCR/ABL fusion gene in Chronic Myelocytic Leukemia. The LNA probe was immobilized on the gold electrode(AuE) through sulfur–Au interaction to construct specific electrochemical biosensor. The electrochemical response of the sensor to hybridization of the LNA probe with the target DNA was studied using [Cu(R)2]2+ as an electrochemical indicator. The optimal condition was discussed. The experimental results indicated that in pH 7.4 PBS buffer solution, this new method has excellent specificity for single base mismatch and complementary after hybridization. The relationship between the …

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Influence Of Tert-Butylpyridine On The Band Energetics Of Nanostructured Tio2 Electrodes And The Photoelectrochemical Properties Of Dye-Seneitized Electrodes, Shu-Ming Yang, Ji-Chao Wang, Hui-Zhi Kou, Hong-Bin Xue, Hong-Jun Wang, Yu-Ling Guo May 2011

Influence Of Tert-Butylpyridine On The Band Energetics Of Nanostructured Tio2 Electrodes And The Photoelectrochemical Properties Of Dye-Seneitized Electrodes, Shu-Ming Yang, Ji-Chao Wang, Hui-Zhi Kou, Hong-Bin Xue, Hong-Jun Wang, Yu-Ling Guo

Journal of Electrochemistry

The flat band edges (Efb) of nanostructured TiO2 electrodes in electrolyte solutions with tert-butylpyridine (TBP) of different concentrations have been determined with spectroelectrochemical technique. TBP played a role in band energetics of nanostructured TiO2 electrodes. The Efb values of -2.25, -2.46 and -2.62 V were determined in three 0.2 mol•L-1 tetrabutylammonium perchlorate (TBAP) acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L-1 TBP respectively. The addition of Li+ ions shifted Efb positively. The Efb values of -1.12, -1.22 and -1.30 V were determined in three 0.2 mol•L-1 LiClO4 acetonitrile electrolytes which contain 0, 0.2 …

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Preparation And Electrocatalytic Activity Of The Pt/Wc/Tio2 Composites, Chun-An Ma, Bin Yu, Mei-Qin Shi, Xiao-Ling Lang May 2011

Preparation And Electrocatalytic Activity Of The Pt/Wc/Tio2 Composites, Chun-An Ma, Bin Yu, Mei-Qin Shi, Xiao-Ling Lang

Journal of Electrochemistry

TiO2 was used as the support for preparation of Pt/WC/TiO2 composite catalyst. The composites were characterized by XRD, SEM and TEM methods. The electrocatalytical activity of Pt/WC/TiO2 composite for oxidation of methanol was investigated by cyclic voltammetry. Pt/WC/TiO2 exhibited higher activity compared with that of Pt/TiO2 and Pt/WC composite catalysts. Based on this we discussed the effects of crystal phases of TiO2 on the electrocatalytical activity of Pt/WC/TiO2 composite catalyst.

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Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen May 2011

Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen

Journal of Electrochemistry

CO2 reduction on Cu(111) single crystal surfaces was studied using DFT calculations on the reaction energies and the minimum energy paths. The results indicated that the possible reaction paths for CO2 reduction on Cu(111) surface are CO2(g) + H* → COOH* → (CO +OH)*, (CO + H)* → CHO*, CHO + H → CH2O* → (CH2+O)*, CH2* + 2H* → CH4 or 2CH2* → C2H4. On Cu(111) surface, the reaction rate is controlled by steps of CH2O* → (CH2 …

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Electrochemical Studies Of Zinc Injection Into The Structure Materials Of Nuclear Power Plants, Sheng-Han Zhang, Yu Tan, Ke-Xin Liang May 2011

Electrochemical Studies Of Zinc Injection Into The Structure Materials Of Nuclear Power Plants, Sheng-Han Zhang, Yu Tan, Ke-Xin Liang

Journal of Electrochemistry

The electrochemical and semiconductor characters of oxide films formed on 304L, 316L stainless steel and alloy 600 in high temperature water with zinc addition were studied. Stress corrosion cracking and occupational radiation can be retarded effectively by zinc injection to the primary circuit of pressurized water reactor (PWR). The semiconductor characters of the materials formed by zinc injection was analyzed by Mott-Schottky curves. The surface morphology and components of the corrosion oxide layer were examined and detected by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The result reveals that the smaller crystals and the complex Zn-Cr-Ni-Fe oxide were …

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Electrochemical Capacitive Performance Of Mesoporous Carbon Based Co-Ni Oxides, Zhen-Sheng Yang, Ling-Bin Kong, Li Deng, Yong-Chun Luo, Long Kang May 2011

Electrochemical Capacitive Performance Of Mesoporous Carbon Based Co-Ni Oxides, Zhen-Sheng Yang, Ling-Bin Kong, Li Deng, Yong-Chun Luo, Long Kang

Journal of Electrochemistry

By using defects on the surface of CMK-3 served as nucleation center, Co0.25Ni0.75 oxide/C composite was successfully prepared through a simple chemical co-precipitation method. Characterization was carried by using X-ray diffraction, BET and scanning electron microscopy. Results showed that a perfect mesoporous network of interconnected nanoflakes was obtained for Co0.25Ni0.75 oxide/C composite and, this material has a less crystallization, interconnected nanoflakes network structure and a narrow mesoporous distribution at about 3~4 nm. The highly dispersed and loosely packed Co0.25Ni0.75 oxide/C composite possessed good electrochemical accessibility and fast diffusion rate of OH …

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Comparison Of Catalytic Performance On Different Materials Supported Pd Catalysts For Formic Acid Oxidation, Su-Dong Yang, Yan-Yu Liang, Zhu-Liang Wen, Qi-Jun Song, Xiao-Gang Zhang May 2011

Comparison Of Catalytic Performance On Different Materials Supported Pd Catalysts For Formic Acid Oxidation, Su-Dong Yang, Yan-Yu Liang, Zhu-Liang Wen, Qi-Jun Song, Xiao-Gang Zhang

Journal of Electrochemistry

Graphite oxide (GO) was prepared from by Hummers method. Then the graphene nanosheets supporting Pd catalysts were prepared by a single-step chemical reduction method. The electrocatalytic performance for formic acid oxidation of the prepared Pd/graphene composite was studied as an electrode material in comparison with the composite catalysts based on the other carbons (MWCNTs, SWCNTs, and Vulcan XC-72 carbon black). X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements indicated that the Pd nanoparticles were well dispersed on the surface of the graphene nanosheets with a small particle size. The electrocatalytic oxidation of formic acid was studied by electrochemically active …

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Cacao Use And The San Lorenzo Olmec, Terry G. Powis, Ann Cyphers, Nilesh W. Gaikwad, Louis Grivetti, Kong Cheong May 2011

Cacao Use And The San Lorenzo Olmec, Terry G. Powis, Ann Cyphers, Nilesh W. Gaikwad, Louis Grivetti, Kong Cheong

Faculty Articles

Mesoamerican peoples had a long history of cacao use—spanning more than 34 centuries—as confirmed by previous identification of cacao residues on archaeological pottery from Paso de la Amada on the Pacific Coast and the Olmec site of El Manatí on the Gulf Coast. Until now, comparable evidence from San Lorenzo, the premier Olmec capital, was lacking. The present study of theobromine residues confirms the continuous presence and use of cacao products at San Lorenzo between 1800 and 1000 BCE, and documents assorted vessels forms used in its preparation and consumption. One elite context reveals cacao use as part of a …

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The Exonuclease Activity Of Hpmc2 Is Required For Transcriptional Regulation Of The Qr Gene And Repair Of Estrogen-Induced Abasic Sites, N. Krishnamurthy, C. R. Ngam, Anthony J. Berdis, M. M. Montano May 2011

The Exonuclease Activity Of Hpmc2 Is Required For Transcriptional Regulation Of The Qr Gene And Repair Of Estrogen-Induced Abasic Sites, N. Krishnamurthy, C. R. Ngam, Anthony J. Berdis, M. M. Montano

Chemistry Faculty Publications

We have previously reported that the expression of antioxidative stress enzymes is upregulated by trans-hydroxytamoxifen (TOT) in breast epithelial cell lines providing protection against estrogen-induced DNA damage. This regulation involves Estrogen Receptor β (ERβ) recruitment to the Electrophile Response Element (EpRE) and a novel protein, human homolog of Xenopus gene which Prevents Mitotic Catastrophe (hPMC2). We have also demonstrated that ERβ and hPMC2 are required for TOT-dependent recruitment of poly (ADP-ribose) polymerase 1 (PARP-1) and Topoisomerase IIβ (Topo IIβ) to the EpRE. Sequence analysis reveals that the C-terminus of hPMC2 encodes a putative exonuclease domain. Using in vitro kinetic assays, …

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Pcr Amplification Of Trypanosoma Cruzi - Specific Dna From Raccoon Blood Samples, Colin Moss May 2011

Pcr Amplification Of Trypanosoma Cruzi - Specific Dna From Raccoon Blood Samples, Colin Moss

Mahurin Honors College Capstone Experience/Thesis Projects

The parasitic protist Trypanosoma cruzi is the causative agent of Chagas Disease. Chagas Disease causes greater than 15,000 deaths each year, and nearly 28 million people are believed to be at risk of infection in Central and South America. This parasite has been described in many mammalian host species and has also been described in the United States. The purpose of this study was to attempt to use PCR to amplify T. cruzi-specific DNA directly from blood samples obtained from raccoons (Procyon lotor) trapped in Warren and Barren Counties of Kentucky in 2007 and 2008. DNA was …

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Determining Protease Substrate Selectivity And Inhibition By Label-Free Supramolecular Tandem Enzyme Assays, Garima Ghale, Vijayakumar Ramalingam, Adam R. Urbach, Werner M. Nau May 2011

Determining Protease Substrate Selectivity And Inhibition By Label-Free Supramolecular Tandem Enzyme Assays, Garima Ghale, Vijayakumar Ramalingam, Adam R. Urbach, Werner M. Nau

Chemistry Faculty Research

An analytical method has been developed for the continuous monitoring of protease activity on unlabeled peptides in real time by fluorescence spectroscopy. The assay is enabled by a reporter pair comprising the macrocycle cucurbit[7]uril (CB7) and the fluorescent dye acridine orange (AO). CB7 functions by selectively recognizing N-terminal phenylalanine residues as they are produced during the enzymatic cleavage of enkephalin-type peptides by the metalloendopeptidase thermolysin. The substrate peptides (e.g., Thr-Gly-Ala-Phe-Met-NH2) bind to CB7 with moderately high affinity (K ≈ 104 M–1), while their cleavage products (e.g., Phe-Met-NH2) bind very tightly (K …

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Profiling Sterols In Cerebrotendinous Xanthomatosis: Utility Of Girard Derivatization And High Resolution Exact Mass Lc-Esi-Msn Analysis, Andrea E. Debarber, Yana Sandlers, Anuradha S. Pappu, Louise S. Merkens, P. Barton Duell, Steven R. Lear, Sandra K. Erickson, Robert D. Steiner May 2011

Profiling Sterols In Cerebrotendinous Xanthomatosis: Utility Of Girard Derivatization And High Resolution Exact Mass Lc-Esi-Msn Analysis, Andrea E. Debarber, Yana Sandlers, Anuradha S. Pappu, Louise S. Merkens, P. Barton Duell, Steven R. Lear, Sandra K. Erickson, Robert D. Steiner

Chemistry Faculty Publications

In this study we profile free 3-oxo sterols present in plasma from patients affected with the neurodegenerative disorder of sterol and bile acid metabolism cerebrotendinous xanthomatosis (CTX), utilizing a combination of charge-tagging and LC-ESI-MSn performed with an LTQ-Orbitrap Discovery instrument. In addition, we profile sterols in plasma from 24-month-old cyp27A1 gene knockout mice lacking the enzyme defective in CTX. Charge-tagging was accomplished by reaction with cationic Girard's P (GP) reagent 1-(carboxymethyl) pyridinium chloride hydrazide, an approach uniquely suited to studying the 3-oxo sterols that accumulate in CTX, as Girard's reagent reacts with the sterol oxo moiety to form charged hydrazone …

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Mmp-13 Selective Α-Sulfone Hydroxamates: A Survey Of P1' Heterocyclic Amide Isosteres, Thomas E. Barta, Daniel P. Becker, Louis J. Bedell, Alan M. Easton May 2011

Mmp-13 Selective Α-Sulfone Hydroxamates: A Survey Of P1' Heterocyclic Amide Isosteres, Thomas E. Barta, Daniel P. Becker, Louis J. Bedell, Alan M. Easton

Chemistry: Faculty Publications and Other Works

Seeking compounds preferentially potent and selective for MMP-13, we reported in the preceding Letter on a series of hydroxamic acids with a flexible benzamide tail groups.(1a) Here, we replace the amide moiety with non-hydrolyzable heterocycles in an effort to improve half-life. We identify a hydroxamate tetrazole 4e that spares MMP-1 and -14, shows >400-fold selectivity versus MMP-8 and >600-fold selectivity versus MMP-2, and has a 4.8 h half-life in rats. X-ray data (1.9 Å) for tetrazole 4c is presented.

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Mmp-13 Selective Alpha-Sulfone Hydroxamates: Identification Of Selective P1' Amides, Yvette M. Fobian, John N. Freskos, Thomas E. Barta, Louis J. Bedell, Daniel Becker May 2011

Mmp-13 Selective Alpha-Sulfone Hydroxamates: Identification Of Selective P1' Amides, Yvette M. Fobian, John N. Freskos, Thomas E. Barta, Louis J. Bedell, Daniel Becker

Chemistry: Faculty Publications and Other Works

Continuing our interest in designing compounds preferentially potent and selective for MMP-13, we report on a series of hydroxamic acids with a flexible amide P1' substituents. We identify an amide which spares both MMP-1 and -14, and shows >500 fold selectivity for MMP-13 versus MMP-2 and -8.

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Experimental Characterization Of The Weakly Anisotropic Cn X(2)Σ(+) + Ne Potential From Ir-Uv Double Resonance Studies Of The Cn-Ne Complex, J. M. Beames, B. A. O'Donnell, M. Ting, M. I. Lester, Thomas Alex Stephenson May 2011

Experimental Characterization Of The Weakly Anisotropic Cn X(2)Σ(+) + Ne Potential From Ir-Uv Double Resonance Studies Of The Cn-Ne Complex, J. M. Beames, B. A. O'Donnell, M. Ting, M. I. Lester, Thomas Alex Stephenson

Chemistry & Biochemistry Faculty Works

IR-UV double resonance spectroscopy has been used to characterize hindered internal rotor states (n(K) = 0(0), 1(1), and 1(0)) of the CN-Ne complex in its ground electronic state with various degrees of CN stretch (nu(CN)) excitation. Rotationally resolved infrared overtone spectra of the CN-Ne complex exhibit perturbations arising from Coriolis coupling between the closely spaced hindered rotor states (1(1) and 1(0)) with two quanta of CN stretch (nu(CN) = 2). A deperturbation analysis is used to obtain accurate rotational constants and associated average CN center-of-mass to Ne separation distances as well as the coupling strength. The energetic ordering and spacings …

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Characterization Of Esterase Activity From The Bacteria, Francisella Tularensis, The Causative Agent Of Tularemia, Leigh Anna Weston May 2011

Characterization Of Esterase Activity From The Bacteria, Francisella Tularensis, The Causative Agent Of Tularemia, Leigh Anna Weston

Undergraduate Honors Thesis Collection

Francisella tularensis is the bacteria responsible for causing the disease tularemia and is listed as one of the top three-biowarfare agents. Among the proteins essential to the virulence and infectivity of F.tularensis are multiple esterases, which are enzymes that break down various ester, thioester, and amide bonds. In this project, the catalytic activity, substrate speci fi city, and structure of a putative esterase from F.tularensis was studied. Latent fluorophores based on the molecule, fluorescein, were unmasked by the enzymatic activity of the esterase and the increase in fluorescence was measured over time to determine how well the e tcrase recognized …

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Chiral Recognition Study Of A Bimolecular Process In Amino Acid Chiral Ionic Liquids, Laurel Millikan Heckman May 2011

Chiral Recognition Study Of A Bimolecular Process In Amino Acid Chiral Ionic Liquids, Laurel Millikan Heckman

Undergraduate Honors Thesis Collection

In this study, chiral ionic liquid (CIL) solvents were prepared and tested for their chiral discrimination ability by probing with luminescence quenching. The CIL's were also tested for their impurities, viscosity and density. These experiments will help to determine the ability of CIL's to act as solvents in asymmetric catalysis. The chiral ionic liquids in this study were composed of amino acid methyl ester cations and bis(trifluoromethane) sulfonimide or bistri flimide anions (i.e. I-alanine methyl ester bistriflimid e, d-alanine methyl ester bistr iflim ide and I-leuci ne methyl ester bistriflimde). Circularly polarized luminescence (CPL) and its quenching in the chiral …

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