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2013

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Articles 1171 - 1200 of 1354

Full-Text Articles in Chemistry

Study Of Charge-Dependent Transport And Toxicity Of Peptide-Functionalized Silver Nanoparticles Using Zebrafish Embryos And Single Nanoparticle Plasmonic Spectroscopy, Kerry J. Lee, Lauren M. Browning, Prakash D. Nallathamby, Xiao-Hong Nancy Xu Jan 2013

Study Of Charge-Dependent Transport And Toxicity Of Peptide-Functionalized Silver Nanoparticles Using Zebrafish Embryos And Single Nanoparticle Plasmonic Spectroscopy, Kerry J. Lee, Lauren M. Browning, Prakash D. Nallathamby, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Nanomaterials possess unusually high surface area-to-volume ratios and surface-determined physicochemical properties. It is essential to understand their surface-dependent toxicity in order to rationally design biocompatible nanomaterials for a wide variety of applications. In this study, we have functionalized the surfaces of silver nanoparticles (Ag NPs, 11.7 ±+2.7 nm in diameter) with three biocompatible peptides (CALNNK, CALNNS, CALNNE) to prepare positively (Ag-CALNNK NPs+ζ), negatively (Ag-CALNNS NPs−2ζ), and more negatively charged NPs (Ag-CALNNE NPs−4ζ), respectively. Each peptide differs in a single amino acid at its C-terminus, which minimizes the effects of peptide sequences and serves as …

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Ace-Fts Observations Of Acetonitrile In The Lower Stratosphere, J. J. Harrison, P. F. Bernath Jan 2013

Ace-Fts Observations Of Acetonitrile In The Lower Stratosphere, J. J. Harrison, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

This work reports the first infrared satellite remote-sensing measurements of acetonitrile (CH3CN) in the Earth's atmosphere using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) between 2004 and 2011. The retrieval scheme uses new quantitative laboratory spectroscopic measurements of acetonitrile (Harrison and Bernath, 2012). Although individual ACE-FTS profile measurements are dominated by measurement noise, median profiles in 10 degrees latitude bins show a steady decline in volume mixing ratio from similar to 150 ppt (parts per trillion) at 11.5 km to < 40 ppt at 25.5-29.5 km. These new measurements agree well with the scant available air-and balloon-borne data in the lower stratosphere. An acetonitrile stratospheric lifetime of 73 ± 20 yr has been determined.

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Role Of Extractable And Residual Organic Matter Fractions On Sorption Of Phenanthrene In Sediments, Yulong Zhang, Yong Ran, Jingdong Mao Jan 2013

Role Of Extractable And Residual Organic Matter Fractions On Sorption Of Phenanthrene In Sediments, Yulong Zhang, Yong Ran, Jingdong Mao

Chemistry & Biochemistry Faculty Publications

Two sediments were demineralized and sequentially fractionated into extracted fractions [free lipid (FL), bound lipid (BL) and lignin (LG)] and residual fractions [free lipid free (FLF), bound lipid free (BLF) and lignin free (LGF)]. The sorption isotherms of phenanthrene (Phen) were examined to evaluate the importance of various fractions on sorption. A lignin extraction procedure was for the first time applied to separate the lignin or degraded lignin fraction from sediment organic matter (SOM). The extracted LG was similar to model lignin in terms of elemental ratios and sorption behavior. FL and LG fractions were quite important, as their contents …

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Interaction Mechanism Of Benzene And Phenanthrene In Condensed Organic Matter: Importance Of Adsorption (Nanopore-Filling), Ke Sun, Yong Ran, Yu Yang, Baoshan Xing, Jingdong Mao Jan 2013

Interaction Mechanism Of Benzene And Phenanthrene In Condensed Organic Matter: Importance Of Adsorption (Nanopore-Filling), Ke Sun, Yong Ran, Yu Yang, Baoshan Xing, Jingdong Mao

Chemistry & Biochemistry Faculty Publications

Although microporosity and surface area of natural organic matter (NOM) are crucial to mechanistic evaluation of the sorption process for nonpolar organic contaminants (NOCs), they have wrongly been estimated by the N2 adsorption technique. Nuclear magnetic resonance spectroscopy (13C NMR), and benzene, carbon dioxide, and nitrogen adsorption techniques were used to characterize structural and surface properties for different condensed NOM samples, which were related to the sorption behavior of phenanthrene (Phen). It was found that the revised Freundlich model by taking the chemical activity into account can well describe the isotherms for benzene and Phen. The benzene …

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Quantifying The Impact Of Boreal Forest Fires On Tropospheric Oxidants Over The Atlantic Using Aircraft And Satellites (Bortas) Experiment: Design, Execution And Science Overview, P. I. Palmer, M. Parrington, J. D. Lee, A, C. Lewis, A. R. Rickard, P. F. Bernath, T. J. Duck, D. L. Waugh, D. W. Tarasick, S. Andrews Jan 2013

Quantifying The Impact Of Boreal Forest Fires On Tropospheric Oxidants Over The Atlantic Using Aircraft And Satellites (Bortas) Experiment: Design, Execution And Science Overview, P. I. Palmer, M. Parrington, J. D. Lee, A, C. Lewis, A. R. Rickard, P. F. Bernath, T. J. Duck, D. L. Waugh, D. W. Tarasick, S. Andrews

Chemistry & Biochemistry Faculty Publications

We describe the design and execution of the BORTAS (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) experiment, which has the overarching objective of understanding the chemical aging of air masses that contain the emission products from seasonal boreal wildfires and how these air masses subsequently impact downwind atmospheric composition. The central focus of the experiment was a two-week deployment of the UK BAe-146-301 Atmospheric Research Aircraft (ARA) over eastern Canada, based out of Halifax, Nova Scotia. Atmospheric ground-based and sonde measurements over Canada and the Azores associated with the planned …

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Ultrasensitive Analysis Of Binding Affinity Of Hiv Receptor And Neutralizing Antibodies Using Solution-Phase Electrochemiluminescence Assay, Xiao-Hong Nancy Xu, Zhaoyang Wen, William J. Brownlow Jan 2013

Ultrasensitive Analysis Of Binding Affinity Of Hiv Receptor And Neutralizing Antibodies Using Solution-Phase Electrochemiluminescence Assay, Xiao-Hong Nancy Xu, Zhaoyang Wen, William J. Brownlow

Chemistry & Biochemistry Faculty Publications

Binding of a few ligand molecules with its receptors on cell surface can initiate cellular signaling transduction pathways, and trigger viral infection of host cells. HIV-1 infects host T-cells by binding its viral envelope protein (gp120) with its receptor (a glycoprotein, CD4) on T cells. Primary strategies to prevent and treat HIV infection is to develop therapies (e.g., neutralizing antibodies) that can block specific binding of CD4 with gp120. The infection often leads to the lower counts of CD4 cells, which makes it an effective biomarker to monitor the AIDS progression and treatment. Despite research over decades, quantitative assays for …

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Improved Method For Quantifying The Air-Sea Flux Of Volatile And Semi-Volatile Organic Carbon, Emily Hauser, Rebecca M. Dickhut, Renee Falconer, Andrew S. Wozniak Jan 2013

Improved Method For Quantifying The Air-Sea Flux Of Volatile And Semi-Volatile Organic Carbon, Emily Hauser, Rebecca M. Dickhut, Renee Falconer, Andrew S. Wozniak

Chemistry & Biochemistry Faculty Publications

A method for quantifying the diffusive air-sea exchange of gaseous organic carbon (OC) was developed. OC compounds were separated into two operational pools-those that were kinetically air limited in diffusion across the air-sea interface and those that were water limited-during simultaneous air/water sampling. The method separates OC compounds into low Henry's law constant (low-H) semivolatile OC (SOC) and high Henry's law constant (high-H) volatile OC (VOC) pools that can be categorized by relating diffusion kinetic parameters to Henry's Law constant. Air limited (low-H; H << similar to 0.1 L atm mol(-1)) compounds were collected in pure water traps and were quantified as dissolved OC, whereas …

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Silver Nanoparticles Induce Developmental Stage-Specific Embryonic Phenotypes In Zebrafish, Kerry J. Lee, Lauren M. Browning, Prakash D. Nallathamby, Christopher J. Osgood, Xiao-Hong Nancy Xu Jan 2013

Silver Nanoparticles Induce Developmental Stage-Specific Embryonic Phenotypes In Zebrafish, Kerry J. Lee, Lauren M. Browning, Prakash D. Nallathamby, Christopher J. Osgood, Xiao-Hong Nancy Xu

Chemistry & Biochemistry Faculty Publications

Much is anticipated from the development and deployment of nanomaterials in biological organisms, but concerns remain regarding their biocompatibility and target specificity. Here we report our study of the transport, biocompatibility and toxicity of purified and stable silver nanoparticles (Ag NPs, 13.1 ± 2.5 nm in diameter) upon the specific developmental stages of zebrafish embryos using single NP plasmonic spectroscopy. We find that single Ag NPs passively diffuse into five different developmental stages of embryos (cleavage, early-gastrula, early-segmentation, late-segmentation, and hatching stages), showing stage-independent diffusion modes and diffusion coefficients. Notably, the Ag NPs induce distinctive stage and dose-dependent phenotypes and …

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Ace-Fts Observations Of Pyrogenic Trace Species In Boreal Biomass Burning Plumes During Bortas, K. A. Tereszchuk, G. G. Abad, C. Clerbaux, J. Hadji-Lazaro, D. Hurtmans, P. F. Coheur, P. F. Bernath Jan 2013

Ace-Fts Observations Of Pyrogenic Trace Species In Boreal Biomass Burning Plumes During Bortas, K. A. Tereszchuk, G. G. Abad, C. Clerbaux, J. Hadji-Lazaro, D. Hurtmans, P. F. Coheur, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

To further our understanding of the effects of biomass burning emissions on atmospheric composition, the BORTAS campaign (BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) was conducted on 12 July to 3 August 2011 during the boreal forest fire season in Canada. The simultaneous aerial, ground and satellite measurement campaign sought to record instances of boreal biomass burning to measure the tropospheric volume mixing ratios (VMRs) of short- and long-lived trace molecular species from biomass burning emissions. The goal was to investigate the connection between the composition and the distribution of these pyrogenic outflows and …

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Ace-Fts Version 3.0 Data Set: Validation And Data Processing Update, Claire Waymark, Kaley A. Walker, Chris D. Boone, Peter F. Bernath Jan 2013

Ace-Fts Version 3.0 Data Set: Validation And Data Processing Update, Claire Waymark, Kaley A. Walker, Chris D. Boone, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

No abstract provided.

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Harmonized Dataset Of Ozone Profiles From Satellite Limb And Occultation Measurements, V. F. Sofieva, N. Rahpoe, J. Tamminen, E. Kyrölä, N. Kalakoski, M. Weber, A. Rozanov, C. Von Savigny, A Laeng, T. Von Clarmann, P. Bernath, R. J. Hargreaves Jan 2013

Harmonized Dataset Of Ozone Profiles From Satellite Limb And Occultation Measurements, V. F. Sofieva, N. Rahpoe, J. Tamminen, E. Kyrölä, N. Kalakoski, M. Weber, A. Rozanov, C. Von Savigny, A Laeng, T. Von Clarmann, P. Bernath, R. J. Hargreaves

Chemistry & Biochemistry Faculty Publications

In this paper, we present a HARMonized dataset of OZone profiles (HARMOZ) based on limb and occultation measurements from Envisat (GOMOS, MIPAS and SCIAMACHY), Odin (OSIRIS, SMR) and SCISAT (ACE-FTS) satellite instruments. These measurements provide high-vertical-resolution ozone profiles covering the altitude range from the upper troposphere up to the mesosphere in years 2001-2012. HARMOZ has been created in the framework of the European Space Agency Climate Change Initiative project. The harmonized dataset consists of original retrieved ozone profiles from each instrument, which are screened for invalid data by the instrument teams. While the original ozone profiles are presented in different …

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Validation Of Stratospheric And Mesospheric Ozone Observed By Smiles From International Space Station, Y. Kasai, H. Sagawa, D. Kreyling, E. Dupuy, P. Baron, J. Mendrok, K Suzuki, T. O. Sato, T. Nishibori, S. Mizobuchi, P. F. Bernath Jan 2013

Validation Of Stratospheric And Mesospheric Ozone Observed By Smiles From International Space Station, Y. Kasai, H. Sagawa, D. Kreyling, E. Dupuy, P. Baron, J. Mendrok, K Suzuki, T. O. Sato, T. Nishibori, S. Mizobuchi, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

We observed ozone O3 in the vertical region between 250 and 0.0005 hPa (~ 12-96 km) using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the Japanese Experiment Module (JEM) of the International Space Station (ISS) between 12 October 2009 and 21 April 2010. The new 4K superconducting heterodyne receiver technology of SMILES allowed us to obtain a one order of magnitude better signal-to-noise ratio for the O3 line observation compared to past spaceborne microwave instruments. The non-sun-synchronous orbit of the ISS allowed us to observe O3 at various local times. We assessed the quality of the vertical …

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The Roles Of Vertical Advection And Eddy Diffusion In The Equatorial Mesospheric Semi-Annual Oscillation (Msao), R. L. Gattinger, E. Kyrölä, C. D. Boone, W. F.J. Evans, K. A. Walker, I. C. Mcdade, P. F. Bernath, E. J. Llewellyn Jan 2013

The Roles Of Vertical Advection And Eddy Diffusion In The Equatorial Mesospheric Semi-Annual Oscillation (Msao), R. L. Gattinger, E. Kyrölä, C. D. Boone, W. F.J. Evans, K. A. Walker, I. C. Mcdade, P. F. Bernath, E. J. Llewellyn

Chemistry & Biochemistry Faculty Publications

Observations of the mesospheric semi-annual oscillation (MSAO) in the equatorial region have been reported dating back several decades. Seasonal variations in both species densities and airglow emissions are well documented. The extensive observations available offer an excellent case study for comparison with model simulations. A broad range of MSAO measurements is summarised with emphasis on the 80-100 km region. The objective here is not to address directly the complicated driving forces of the MSAO, but rather to employ a combination of observations and model simulations to estimate the limits of some of the underlying dynamical processes. Photochemical model simulations are …

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Low Root Zone Temperature Limits Nutrient Effects On Cucumber Seedling Growth And Induces Adversity Physiological Response, Qiu-Yan Yan, Zeng-Qiang Duan, Jing-Dong Mao, Xun Li, Fei Dong Jan 2013

Low Root Zone Temperature Limits Nutrient Effects On Cucumber Seedling Growth And Induces Adversity Physiological Response, Qiu-Yan Yan, Zeng-Qiang Duan, Jing-Dong Mao, Xun Li, Fei Dong

Chemistry & Biochemistry Faculty Publications

Effects of root-zone temperatures (RZT) (12°C-RZT and 20°C-RZT) and different N, P, and K nutrient regimes on the growth, reactive oxygen species (ROS), and antioxidant enzyme in cucumber seedlings were investigated in hydroponics. Strong interactions were observed between RZT and nutrient on the dry weight (P=0.001), root length (P=0.001) and leaf area (P=0.05). Plant dry weights were suppressed at low RZT of 12°C, while higher biomass and growth of cucumber seedlings were produced at elevated RZT of 20°C under each nutrient treatment. Growth indexes (plant height, internode length, root length, and leaf area) at 12°C-RZT had less difference among nutrient …

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Crystal Growth And An Investigation Of Structural Stability: Synthesis, Structure, And Physical Properties Of Yb(Mn,M)Xal12-X (M = Fe, Ru; X < 2.5) And Lnmnxga3 (Ln = Ho-Tm; X < 0.15), Bradford Wesley Fulfer Jan 2013

Crystal Growth And An Investigation Of Structural Stability: Synthesis, Structure, And Physical Properties Of Yb(Mn,M)Xal12-X (M = Fe, Ru; X < 2.5) And Lnmnxga3 (Ln = Ho-Tm; X < 0.15), Bradford Wesley Fulfer

LSU Doctoral Dissertations

The contents of this dissertation describe the crystal growth, crystal structures, and physical properties of ternary intermetallic aluminides and gallides. These compounds are grown in an effort to determine how controlling reaction ratios using the flux growth method can impact chemical structure and physical properties. Three specific examples are given where slight changes in reaction ratios leads to crystalline products that adopt various structure types. LnMn2+xAl10-x (Ln = Gd, Yb) crystals adopt the CaCr2Al10 and ThMn12 structure types. We compare LnMn2+xAl10-x compounds adopting the CaCr2Al10 and ThMn12 structure types, and outline synthesis methods to obtain each polymorph. Magnetic susceptibility measurements …

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Design, Synthesis, And Characterization Of Porphyrin Derivatives For Biological Applications, Raja Gabadage Waruna Eranga Jinadasa Jan 2013

Design, Synthesis, And Characterization Of Porphyrin Derivatives For Biological Applications, Raja Gabadage Waruna Eranga Jinadasa

LSU Doctoral Dissertations

Chapter 1 of this Dissertation presents a brief introduction to the basic properties of porphyrins and their derivatives (hydroporphyrins), their abundance and functions in the nature, and their applications in photodynamic therapy. Chapter 2 reports the synthesis, characterization, conformational analysis and cellular studies of novel mono conjugated regioisomers of chlorin e6 derivatives that are promising photosensitizers for photodynamic therapy. All three regioisomers were synthesized from pheophytin a, which was extracted from the alga Spirulina pacifica. In vitro investigations using human carcinoma HEp2 cells show that the 152-lysyl regioisomers accumulate the most within cells, and the most phototoxic …

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Oligomers Of Beta-L-Arabinosides Of Hydroxyproline : Synthesis Of The Carbohydrate Epitope Of The Art V 1 Allergen, Ning Xie Jan 2013

Oligomers Of Beta-L-Arabinosides Of Hydroxyproline : Synthesis Of The Carbohydrate Epitope Of The Art V 1 Allergen, Ning Xie

LSU Doctoral Dissertations

The pollen of mugwort is a major contributor to hay fever in Europe and North America. The chemical structure of Art v 1, the major allergen of mugwort, has been elucidated. A notable motif in Art v 1 – characterized by clusters of contiguous â-arabinosides of hydroxyproline – was found to be a key recognition element for antibodies generated in response to the natural protein. This dissertation details the chemical synthesis of oligomers of â-arabinosides of hydroxyproline and the search to establish the minimal carbohydrate epitope of Art v 1. The â-arabinoside motif, being a 1,2-cis glycoside, presents a considerable …

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Surface Studies Of Organic Thin Films Using Scanning Probe Microscopy And Nanofabrication, Venetia Denae Lyles Jan 2013

Surface Studies Of Organic Thin Films Using Scanning Probe Microscopy And Nanofabrication, Venetia Denae Lyles

LSU Doctoral Dissertations

Porphyrins and metalloporphyrins have unique chemical and electronic properties and thus provide useful model structures for nanoscale studies of the role of chemical structure for electronic properties. Porphyrins have been proposed as viable materials for molecular-based information-storage devices, gas sensors, photovoltaic cells, organic light-emitting diodes and molecular wires. The function and efficiency of porphyrins in devices is largely attributable to molecular architecture and how the molecules are self-organized. Modifications of the porphyrin macrocycle, peripheral groups or bound metal ions can generate a range of electrical, photoelectrical or magnetic properties. The conductive properties are greatly influenced at the molecular level by …

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Complexity-Driven Properties Of The Intermetallic Compounds Gd₁₁₇Co₅₆Sn₁₁₂ And Ln₃₀Ru₄Sn₃₁ (Ln = Gd And Tb), Devin Charles Schmitt Jan 2013

Complexity-Driven Properties Of The Intermetallic Compounds Gd₁₁₇Co₅₆Sn₁₁₂ And Ln₃₀Ru₄Sn₃₁ (Ln = Gd And Tb), Devin Charles Schmitt

LSU Doctoral Dissertations

Understanding the relationships between the structure of materials and their properties in extended solid systems is a necessity when intuitively designing functional materials. One of the most fundamental properties of a material is its ability to transport heat, which is linked to the lattice complexity of the material. Here, the single crystalline materials Gd117Co56Sn112 and Tb30Ru4Sn31 are grown to study the pronounced effect of a complexity-driven reduction of lattice thermal conductivity. The transport and magnetic properties of Gd117Co56Sn112 and Ln30Ru4Sn31 (Ln = Gd and Tb) are also presented and related to other systems. Tb30Ru4Sn31 is found to be a large …

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Broadband Fourier Transform Rotational Spectroscopy For Structure Determination: The Water Heptamer, Cristóbal Pérez, Simon Lobsiger, Nathan A. Seifert, Daniel P. Zaleski, Berhane Temelso, George C. Shields, Zbigniew Kisiel, Brooks H. Pate Jan 2013

Broadband Fourier Transform Rotational Spectroscopy For Structure Determination: The Water Heptamer, Cristóbal Pérez, Simon Lobsiger, Nathan A. Seifert, Daniel P. Zaleski, Berhane Temelso, George C. Shields, Zbigniew Kisiel, Brooks H. Pate

Faculty Journal Articles

Over the recent years chirped-pulse, Fourier-transform microwave (CP-FTMW) spectrometers have chan- ged the scope of rotational spectroscopy. The broad frequency and large dynamic range make possible structural determinations in molecular systems of increasingly larger size from measurements of heavy atom (13C, 15N, 18O) isotopes recorded in natural abundance in the same spectrum as that of the parent isotopic species. The design of a broadband spectrometer operating in the 2–8 GHz frequency range with further improvements in sensitivity is presented. The current CP-FTMW spectrometer performance is benchmarked in the analyses of the rotational spectrum of the water …

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The Relation Between Atmospheric Humidity And Temperature Trends For Stratospheric Water, S. Fueglistaler, Y. S. Liu, T. J. Flannaghan, P. H. Haynes, D. P. Dee, W. J. Read, E. E. Remsberg, L. W. Thomason, D. F. Hurst, J. R. Lanzante, P. F. Bernath Jan 2013

The Relation Between Atmospheric Humidity And Temperature Trends For Stratospheric Water, S. Fueglistaler, Y. S. Liu, T. J. Flannaghan, P. H. Haynes, D. P. Dee, W. J. Read, E. E. Remsberg, L. W. Thomason, D. F. Hurst, J. R. Lanzante, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

We analyze the relation between atmospheric temperature and water vapor-a fundamental component of the global climate system-for stratospheric water vapor (SWV). We compare measurements of SWV (and methane where available) over the period 1980-2011 from NOAA balloon-borne frostpoint hygrometer (NOAA-FPH), SAGE II, Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS)/Aura, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) to model predictions based on troposphere-to-stratosphere transport from ERA-Interim, and temperatures from ERA-Interim, Modern Era Retrospective- Analysis (MERRA), Climate Forecast System Reanalysis (CFSR), Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC), HadAT2, and RICHv1.5. All model predictions are dry biased. The interannual …

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Hydrocarbons In The Upper Troposphere And Lower Stratosphere Observed From Ace-Fts And Comparisons With Waccm, Mijeong Park, William J. Randel, Douglas E. Kinnison, Louisa K. Emmons, Peter F. Bernath, Kaley A. Walker, Chris D. Boone, Nathaniel J. Livesey Jan 2013

Hydrocarbons In The Upper Troposphere And Lower Stratosphere Observed From Ace-Fts And Comparisons With Waccm, Mijeong Park, William J. Randel, Douglas E. Kinnison, Louisa K. Emmons, Peter F. Bernath, Kaley A. Walker, Chris D. Boone, Nathaniel J. Livesey

Chemistry & Biochemistry Faculty Publications

Satellite measurements from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) are used to examine the global, seasonal variations of several hydrocarbons, including carbon monoxide (CO), ethane (C2H6), acetylene (C2H2), and hydrogen cyanide (HCN). We focus on quantifying large-scale seasonal behavior from the middle troposphere to the stratosphere, particularly in the tropics, and furthermore make detailed comparisons with the Whole Atmosphere Community Climate Model (WACCM) chemistry climate model (incorporating tropospheric photochemistry, time-varying hydrocarbon emissions, and meteorological fields nudged from reanalysis). Comparisons with Microwave Limb Sounder (MLS) measurements of CO are also included …

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A Preliminary Examination Of An In Situ Dual Dye Approach To Measuring Light Fluxes In Lotic Systems, Elizabeth C. Minor, Elizabeth James, Jay A. Austin, Veronica Nelson, Ryan Lusk, Kenneth Mopper Jan 2013

A Preliminary Examination Of An In Situ Dual Dye Approach To Measuring Light Fluxes In Lotic Systems, Elizabeth C. Minor, Elizabeth James, Jay A. Austin, Veronica Nelson, Ryan Lusk, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

Light is a critical parameter in aquatic ecosystems, affecting primary production and in situ photochemistry. However, measuring light exposure for suspended particles or dissolved components in a dynamic water column can be challenging with existing Eulerian approaches. Here, we assess the simultaneous deployment of two dyes differing in photolability (rhodamine WT and fluorescein) as a Lagrangian measure of sunlight exposure in a lotic system. Fluorescein is sensitive to light exposure; rhodamine WT is relatively photostable. We examined dye fluorescence at various pH, salinity, and temperature conditions. We also tested dye photolability as a function of pH and wavelength range. In …

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Interaction Of Ceo2 And Zno Nanoparticles Towards The Symbiotic Association Of Alfalfa (Medicago Sativa) And Sinorhizobium Meliloti In Soil, Susmita Bandyopadhyay Jan 2013

Interaction Of Ceo2 And Zno Nanoparticles Towards The Symbiotic Association Of Alfalfa (Medicago Sativa) And Sinorhizobium Meliloti In Soil, Susmita Bandyopadhyay

Open Access Theses & Dissertations

The production of engineered nanoparticles (ENPs) has rapidly increased due to their wide range of applications in the field of electronics, medicine, chemistry and biology. Consequently, concerns have risen about the environmental release and potential negative impact of NPs. A few reports have described the effects of TiO2 NPs and quantum dots upon nitrogen fixing bacteria. However, the understanding of the interaction of NPs in plant-microbe interface (symbiotic association), like alfalfa (Medicago sativa L.)-Sinorhizobium meliloti, is still in its infancy. Alfalfa is the world's most important forage crop. It grows in association with S. meliloti, which is very important in …

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Preparation Of Cobalt/Nickel Molybdenum Sulfide Catalysts Supported By Aqueous Media Soluble Multi-Wall Carbon Nanotubes., Hassan Ahmad Bleibel Jan 2013

Preparation Of Cobalt/Nickel Molybdenum Sulfide Catalysts Supported By Aqueous Media Soluble Multi-Wall Carbon Nanotubes., Hassan Ahmad Bleibel

Open Access Theses & Dissertations

Multi-walled carbon nanotubes (MWCNTs) have been subjected to chemical treatment in order to introduce hydrophilic functional groups on their surfaces. These covalently bonded groups did enhance the solubility of MWCNTs in aqueous media as expected. Functionalized MWCNTs were characterized using FTIR, Raman spectroscopy, TGA, X-ray diffraction, dispersion test and TEM. Then, functionalized MWCNTs were incorporated in the hydrothermal synthesis method of transition metal sulfide catalysts (CoMo, NiMo, and Ethylenediamine-CoMo Sulfides). Catalysts were characterized using X-ray diffraction, TEM, SEM, N2 Gas adsorption-desorption, elemental analysis, and Hydrodesulfurization (HDS) reaction of dibenzothiophene (DBT). The objective was to study the functionalized MWCNTs' effect; being …

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Method Development For A Chemical And Biological Analysis Of Glucocorticoids In Wastewater, Maria Carmen Lozano Jan 2013

Method Development For A Chemical And Biological Analysis Of Glucocorticoids In Wastewater, Maria Carmen Lozano

Open Access Theses & Dissertations

Glucocorticoids are a class of steroid hormones that can either be produced synthetically or naturally by the adrenal glands. The synthetic glucocorticoids are highly prescribed in the United States for their anti-inflammatory and immunosuppressive properties to treat a variety of ailments and diseases; however, these have been implicated in a number of adverse human conditions such as obesity, metabolic syndrome, immune-suppression, delayed puberty, adrenal insufficiency and Cushing Syndrome, among others. Ongoing research has shown that synthetic and natural hormones are transported to aquatic environments via mammalian excretion or wastewater effluent, and as a result, the release of glucocorticoids into the …

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Organic Photovoltaics: A Charge Transfer Perspective In The Study Of Donor-Acceptor Systems, Marco Olguin Jan 2013

Organic Photovoltaics: A Charge Transfer Perspective In The Study Of Donor-Acceptor Systems, Marco Olguin

Open Access Theses & Dissertations

The present research involves the study of donor-acceptor (D/A) dyad complexes from a charge transfer energy perspective. The aim is to provide insight and predictive understanding into the charge transfer processes of the molecular-level components in donor-acceptor based organic solar cells using computational methods to describe photochemical processes at the quantum mechanical level within the Density Functional Theory (DFT) approximation. Predictive understanding is anchored in reproducing experimental results, wherein the present work a perturbative excited-state DFT method is described in detail and shown to give Charge Transfer (CT) energies in excellent agreement with benchmark experimental data. With an accurate excited …

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Impact Of Cerium Oxide Nanoparticles On Cilantro (Coriandrum Sativum), Maria Isabel Morales Jan 2013

Impact Of Cerium Oxide Nanoparticles On Cilantro (Coriandrum Sativum), Maria Isabel Morales

Open Access Theses & Dissertations

Studies have shown that plants exposed to ENPs suffer different types of stress. Other studies have revealed that plants can take up and accumulate CeO2 NPs without modification. Thus, these NPs could enter the food chain through edible plants, posing a threat for human health. Cilantro (Coriandrum sativum) is a worldwide culinary and medicinal plant consumed either as a fresh herb or a spice. In this research, cilantro plants were germinated and cultivated for 30 days in organic soil treated with CeO2 NPs at concentrations varying from 0 to 500 mg kg!1. Subsequently, plant organs were analyzed by using spectroscopic …

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Photochemical Synthesis Of Amino Acid And Peptide Oxo-Esters, Alfredo Ornelas Jan 2013

Photochemical Synthesis Of Amino Acid And Peptide Oxo-Esters, Alfredo Ornelas

Open Access Theses & Dissertations

Amino acid and peptide oxo-esters have played an important role in peptide chemistry for many years. Various amino acid esters are commonly used as protecting groups for peptide synthesis in solution. Moreover, activated phenyl ester derivatives have been used for chemical ligation of peptides. However, the synthesis of amino acid and peptide oxo-esters is commonly performed under acidic or basic conditions. Under acidic conditions, acid-sensitive protecting groups may be cleaved, and under basic conditions racemization of amino acid esters is a common problem. Here we present the photochemical synthesis of amino acid and peptide oxo-esters. Based on the photochemical properties …

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Novel Copper (Ii) Mediated Transfection Nano-Systems And Biological Properties Of Pyridinium Surfactants, Sarit Pal Jan 2013

Novel Copper (Ii) Mediated Transfection Nano-Systems And Biological Properties Of Pyridinium Surfactants, Sarit Pal

Open Access Theses & Dissertations

Efficacy of gene therapy is relied upon the improvement of gene delivery vectors into mammalian cells. Although viral-based polynucleotide carriers are still considered as the most common method for gene delivery but the cost effectiveness, nonspecific lethal immune response has evoked the renaissance of non-viral synthetic delivery systems. An initial discovery by Felgnar et al showed Cationic Liposomes (CLs) (having an overall positive charge) when mixed with DNA to form CL-DNA complexes can enhance the transfer of polynucleotides into cells followed by its expression. Presently, a flurry of experimental works is taking place for the better understanding of structural characterization …

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