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Full-Text Articles in Chemistry
Insights On Dissolved Organic Matter Production Revealed By Removal Of Charge-Transfer Interactions In Senescent Leaf Leachates, Karl M. Meingast, Brice K. Grunert, Sarah A. Green, Evan S. Kane, Nastaran Khademimoshgenani
Insights On Dissolved Organic Matter Production Revealed By Removal Of Charge-Transfer Interactions In Senescent Leaf Leachates, Karl M. Meingast, Brice K. Grunert, Sarah A. Green, Evan S. Kane, Nastaran Khademimoshgenani
Michigan Tech Publications
Dissolved organic matter (DOM) is a critical part of the global carbon cycle. Currently, it is understood that at least a portion of the chromophoric DOM (CDOM) character can be described through an electronic interaction of charge transfer (CT) complexes. While much work has been done to understand the influence of CT on soil and aquatic reference standard DOM, little is known about the influence of CT in fresh terrestrially derived DOM. In this study, leaf litter leachates from three tree species were treated (reduced) with sodium borohydride to determine the contribution of CT on a source of fresh terrestrial …
An International Laboratory Comparison Of Dissolved Organic Matter Composition By High Resolution Mass Spectrometry: Are We Getting The Same Answer?, Jeffrey A. Hawkes, Juliana D'Andrilli, Jeffrey N. Agar, Mark P. Barrow, Stephanie M. Berg, Núria Catalán, Hongmei Chen, Rosalie K. Chu, Richard B. Cole, Thorsten Dittmar, Rémy Gavard, Gerd Gleixner, Patrick G. Hatcher, Chen He, Nancy J. Hess, Ryan H.S. Hutchins, Amna Ijaz, Hugh E. Jones, William Kew, Maryam Khaksari, Diana Catalina Palacio Lozano, Jitao Lv, Lynn Mazzoleni, Beatriz E. Noriega-Ortega, Helena Osterholz, Nikola Radoman, Shuzhen Zhang, Phoebe Zito, David C. Podgorski
An International Laboratory Comparison Of Dissolved Organic Matter Composition By High Resolution Mass Spectrometry: Are We Getting The Same Answer?, Jeffrey A. Hawkes, Juliana D'Andrilli, Jeffrey N. Agar, Mark P. Barrow, Stephanie M. Berg, Núria Catalán, Hongmei Chen, Rosalie K. Chu, Richard B. Cole, Thorsten Dittmar, Rémy Gavard, Gerd Gleixner, Patrick G. Hatcher, Chen He, Nancy J. Hess, Ryan H.S. Hutchins, Amna Ijaz, Hugh E. Jones, William Kew, Maryam Khaksari, Diana Catalina Palacio Lozano, Jitao Lv, Lynn Mazzoleni, Beatriz E. Noriega-Ortega, Helena Osterholz, Nikola Radoman, Shuzhen Zhang, Phoebe Zito, David C. Podgorski
Michigan Tech Publications
High-resolution mass spectrometry (HRMS) has become a vital tool for dissolved organic matter (DOM) characterization. The upward trend in HRMS analysis of DOM presents challenges in data comparison and interpretation among laboratories operating instruments with differing performance and user operating conditions. It is therefore essential that the community establishes metric ranges and compositional trends for data comparison with reference samples so that data can be robustly compared among research groups. To this end, four identically prepared DOM samples were each measured by 16 laboratories, using 17 commercially purchased instruments, using positive-ion and negative-ion mode electrospray ionization (ESI) HRMS analyses. The …
Role Of Structural Dynamics In Selectivity And Mechanism Of Non-Heme Fe(Ii) And 2-Oxoglutarate-Dependent Oxygenases Involved In Dna Repair, Sodiq Waheed, Rajeev Ramanan, Shobhit Chaturvedi, Nicolai Lehnert, Christopher J. Schofield, Christo Z. Christov, Tatyana Karabencheva-Christova
Role Of Structural Dynamics In Selectivity And Mechanism Of Non-Heme Fe(Ii) And 2-Oxoglutarate-Dependent Oxygenases Involved In Dna Repair, Sodiq Waheed, Rajeev Ramanan, Shobhit Chaturvedi, Nicolai Lehnert, Christopher J. Schofield, Christo Z. Christov, Tatyana Karabencheva-Christova
Michigan Tech Publications
AlkB and its human homologue AlkBH2 are Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenases that repair alkylated DNA bases occurring as a consequence of reactions with mutagenic agents. We used molecular dynamics (MD) and combined quantum mechanics/molecular mechanics (QM/MM) methods to investigate how structural dynamics influences the selectivity and mechanisms of the AlkB- and AlkBH2-catalyzed demethylation of 3-methylcytosine (m3C) in single (ssDNA) and double (dsDNA) stranded DNA. Dynamics studies reveal the importance of the flexibility in both the protein and DNA components in determining the preferences of AlkB for ssDNA and of AlkBH2 for dsDNA. Correlated motions, including of a …
Richardsite, Zn2cugas4, A New Gallium-Essential Member Of The Stannite Group From The Gem Mines Near Merelani, Tanzania, Luca Bindi, John A. Jaszczak
Richardsite, Zn2cugas4, A New Gallium-Essential Member Of The Stannite Group From The Gem Mines Near Merelani, Tanzania, Luca Bindi, John A. Jaszczak
Michigan Tech Publications
The new mineral richardsite occurs as overgrowths of small (50–400 μm) dark gray, disphenoidal crystals with no evident twinning, but epitaxically oriented on wurtzite–sphalerite crystals from the gem mines near Merelani, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania. Associated minerals also include graphite, diopside, and Ge,Ga-rich wurtzite. It is brittle, dark gray in color, and has a metallic luster. It appears dark bluish gray in reflected plane-polarized light, and is moderately bireflectant. It is distinctly anisotropic with violet to light-blue rotation tints with crossed polarizers. Reflectance percentages for Rmin and Rmax in air at the respective wavelengths are 23.5, 25.0 …
Targeting Oncogenic K-Ras And Monoamine Oxidase B Utilizing Chalcones Bearing The 3,4,5-Trimethoxyphenyl Motif, Cody Fourman
Targeting Oncogenic K-Ras And Monoamine Oxidase B Utilizing Chalcones Bearing The 3,4,5-Trimethoxyphenyl Motif, Cody Fourman
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Oncogenic K-Ras is a driver protein found in specific cancers and was once thought to be “undruggable.” However, recent advances have suggested that mislocalizing K-Ras from the plasma membrane could be a viable strategy to target these cancers. The objective of this project was to identify a lead compound and determine a structure-activity relationship from chalcones bearing the 3,4,5-trimethoxy motif towards oncogenic K-Ras and MAO-B. This was accomplished by keeping the trimethoxy group consistent on one ring while varying the electron-donating or -withdrawing groups on the opposite ring. Previous work showed chalcones of this specific archetype exhibiting indiscriminate MAO inhibition, …
Development Of Tetrathiafulvalene Fused N-Heterocyclic Carbene Compounds, William J. Robinson Iii
Development Of Tetrathiafulvalene Fused N-Heterocyclic Carbene Compounds, William J. Robinson Iii
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Separately, N-Heterocyclic carbene and Tetrathiafulvalene compounds show great promise for a variety of applications. N-heterocyclic carbenes exhibit desirable metal bonding characteristics which allow for modulation of the metal center via back-bonding interactions. Additionally, this creates a system of increased bonding strength creating stable complexes. Tetrathiafulvalene exhibits strong redox-active and optical characteristics. These are owed to an increased aromaticity as oxidation of the compound occurs and thus, is stable through a multitude of oxidative states. The marriage of these two functionalization creates a unique opportunity for a “cure-all” compound, able to address many problems the world faces today including, but not …
Introducing Functionality To Poly(Arylene Ether)S Via Modification Of Diphenyl Sulfone – Type Monomers, Zahida Humayun
Introducing Functionality To Poly(Arylene Ether)S Via Modification Of Diphenyl Sulfone – Type Monomers, Zahida Humayun
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The synthesis of poly(arylene ether)s, with a pendent aryl iodide, was achieved via nucleophilic aromatic substitution (NAS) polycondensation of DI-DFDPS monomer. The platform diiodo-difluorodiphenyl sulfone monomer, DFDPS-DI (3), was prepared in one-step, via EAS chemistry. Structural characterization was provided by NMR spectroscopy, GC/MS, and elemental analysis. As “pre” approach didn’t work here, so “post” approach was used to synthesize N-heterocycle functionalized copolymers. The DI-copolymers were subjected to copper-catalyzed C-N coupling reaction with carbazole, phenoxazine, and indole and the syntheses of chromophore based copolymer were successfully carried out. A series of PAEs containing carbazole, phenoxazine, and indole substituents were synthesized and …
Quantum Chemical Pka Estimation Of Carbon Acids, Saturated Alcohols, And Ketones Via Quantitative Structure-Activity Relationships, Corey Adam Baldasare
Quantum Chemical Pka Estimation Of Carbon Acids, Saturated Alcohols, And Ketones Via Quantitative Structure-Activity Relationships, Corey Adam Baldasare
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Acid dissociation constants, often expressed as pKa values, afford vital information with regards to molecular behavior in various environments and are of significance in fields of organic, inorganic, and medicinal chemistry. Several quantitative structure-activity relationships (QSARs) were developed that correlate experimental pKas for a given class of compounds with a descriptor(s) calculated using density functional theory at the B3LYP/6-31+G** level utilizing the CPCM solvent model. A set of carbon acids provided a good final QSAR model of experimental aqueous pKas versus ΔEH2O (R2 = 0.9647) upon removal of three aldehydes as outliers. A study of saturated alcohols offered a final …
Organic Blue Tadf Chromophore Tag For Monitoring Transfection Studies, Brandon G. Bresler
Organic Blue Tadf Chromophore Tag For Monitoring Transfection Studies, Brandon G. Bresler
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A novel organic TADF chromophore was synthesized via a 3-step process to emit a blue fluorescent light upon excitation. The chromophore was covalently attached to a 61% isobutyryl amidated poly(ethyleneimine) (PEI-IBAm0.61) non-viral gene vector utilized in gene transfection experiments. The gene vectors are loaded with a green fluorescent protein (GFP) and are monitored via fluorescence microscopy. The addition of the blue chromophore therefore allows for the monitoring of the movements of the PEI-IBAm0.61 through the full delivery mechanism of the GFP inside the cells. This can give vital information about the overall toxicity of these non-viral gene vectors to biological …
Investigating Heterogeneous Nucleation Of Barite Using Hydrothermal Atomic Force Microscopy And Optical Microscopy, Ankita B. Gurav
Investigating Heterogeneous Nucleation Of Barite Using Hydrothermal Atomic Force Microscopy And Optical Microscopy, Ankita B. Gurav
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In order to develop a better understanding heterogeneous nucleation of barite, barite precipitation was studied under varying experimental parameters. Hydrothermal atomic force microscopy (HAFM) and optical microscopy were used to investigate the effect of change in temperature, supersaturation and varying ratios of ions on heterogeneous nucleation of barite. In the experiments conducted at higher temperatures, the particles thus nucleated were found to display characteristic hexagonal and rhomboidal shapes. In comparing results of particle densities among different ion ratios, there is evidence suggesting that barium to sulfate ratio plays a role of promoter. Wherein, the ratios with higher [Ba2+] concentration were …
Exploring The Multiplex Detection Capabilities Of Raman Spectroscopy On Mock Street Samples Containing Illicitly Manufactured Fentanyls, Mia Laverne Williams Burnett
Exploring The Multiplex Detection Capabilities Of Raman Spectroscopy On Mock Street Samples Containing Illicitly Manufactured Fentanyls, Mia Laverne Williams Burnett
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Illicitly manufactured fentanyls (IMFs) have become a global and local epidemic and have recently caused an increase in the number of accidental exposures and overdoses in first responders and the community. The aim of the research is to explore a method to discriminate between IMFs and cutting agents in mock street samples using Raman Spectroscopy. Predominant Raman bands corresponding to the structural moieties of each individual illicit, licit drugs, and cutting agents were tracked, then used to discriminate between varying components in a mock street sample. In conclusion, discrimination between the components in the mixture was obtained using Raman Spectroscopy. …