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- AGGREGATION-INDUCED EMISSION; THERMAL-DEGRADATION; DESIGN; ELECTROLUMINESCENCE; PHOTOLUMINESCENCE (2)
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- PHOTOACOUSTIC CONTRAST AGENT; DEEP-TISSUE; UP-CONVERSION; AMINO-ACIDS; NANOPARTICLES; LUMINESCENCE; PERSISTENT; GLASS; MASS (2)
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- Ambrosia salsola; Ambrosia dumosa; beta-Hydroxydihydrochalcones; fungitoxic and phytotoxic compounds; confertin; X-ray diffraction; SESQUITERPENE LACTONES; TRANS-CHALCONE; FLAVONOIDS; PLANTS (1)
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Articles 1 - 30 of 37
Full-Text Articles in Physical Sciences and Mathematics
Conformational Polymorphism In Organic Crystals: Structural And Functional Aspects - A Review, Bidisha Sengupta, Pradeep K. Sengupta, Romans Grant1, Matthew Beasley1, Benjamin Mason1, Tanesha Love1, Larissa Barroso9, Mariela Alvarado9, M S. Zaman
Conformational Polymorphism In Organic Crystals: Structural And Functional Aspects - A Review, Bidisha Sengupta, Pradeep K. Sengupta, Romans Grant1, Matthew Beasley1, Benjamin Mason1, Tanesha Love1, Larissa Barroso9, Mariela Alvarado9, M S. Zaman
Faculty Publications
Polymorphism in organic crystals involves the formation of isomeric molecular identities. It is dependent on the structural arrangement due to inter-atomic interactions, as well as external stimuli, which include temperature, visible and UV radiation. Conformational polymorphism of organic crystalline molecules is often the result of isomerism due to the twisting and turning of angular bonds. The arrangement of the atoms supports different types of bonding mechanisms (which include hydrogen bonding) within the same compound. This, in turn, results in the formation of cis/trans configurational isomers or a proton transfer species (tautomer), having different functional properties. The conformers support the flexibility …
Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu
Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu
Faculty Publications
Changing functionalities of materials using simple methods is an active area of research, as it is "green" and lowers the developing cost of new products for the enterprises. A new small molecule racemic N,N-dimethyl aspartic acid has been prepared. Its structure is determined by single-crystal X-ray diffraction. It is characterized by FTIR, XPS, 1 H NMR, and mass spectroscopy. Its near-infrared luminescence can be enhanced by the combination of metal ions, including Dy3+, Gd3+, Nd3+, Er3+, Sr3+, Y3+, Zn2+, Zr4+, Ho3+, Yb3+, La3+, Pr6+/Pr3+, and Sm3+ ions. An optical chemistry mechanism upon interaction between the sensitizer and activator is proposed. …
Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu
Simultaneous Enhancement Of Near-Infrared Emission And Dye Photodegradation In A Racemic Aspartic Acid Compound Via Metal-Ion Modification, Frank R. Fronczek, Jian Xu
Faculty Publications
Changing functionalities of materials using simple methods is an active area of research, as it is "green" and lowers the developing cost of new products for the enterprises. A new small molecule racemic N,N-dimethyl aspartic acid has been prepared. Its structure is determined by single-crystal X-ray diffraction. It is characterized by FTIR, XPS, 1 H NMR, and mass spectroscopy. Its near-infrared luminescence can be enhanced by the combination of metal ions, including Dy3+, Gd3+, Nd3+, Er3+, Sr3+, Y3+, Zn2+, Zr4+, Ho3+, Yb3+, La3+, Pr6+/Pr3+, and Sm3+ ions. An optical chemistry mechanism upon interaction between the sensitizer and activator is proposed. …
Stretchable Self-Healable Semiconducting Polymer Film For Active-Matrix Strain-Sensing Array, Jin Young Oh, Donghee Son, Toru Katsumata, Yeongjun Lee, Yeongin Kim, Jeffrey Lopez, Hung-Chin Wu, Jiheong Kang, Joonsuk Park, Xiaodan Gu, Jaewan Mun, Nathan Ging-Ji Wang, Yikai Yin, Wei Cai, Youngjun Yun, Jeffrey B.-H. Tok, Zhenan Bao
Stretchable Self-Healable Semiconducting Polymer Film For Active-Matrix Strain-Sensing Array, Jin Young Oh, Donghee Son, Toru Katsumata, Yeongjun Lee, Yeongin Kim, Jeffrey Lopez, Hung-Chin Wu, Jiheong Kang, Joonsuk Park, Xiaodan Gu, Jaewan Mun, Nathan Ging-Ji Wang, Yikai Yin, Wei Cai, Youngjun Yun, Jeffrey B.-H. Tok, Zhenan Bao
Faculty Publications
Skin-like sensory devidces shoud be stretchable and self-healable to meet the demands for future electronic skin applications. Despite recent notable advances in skin-inspired electronic materials, it remains challenging to confer these desired functionalities to an active semiconductor. Here, we report a strain-sensitive, stretchable, and autonomously self-healable semiconducting film achieved through blending of a polymer semiconductor and a self-healable elastomer, both of which are dynamically cross-linked by metal coordination. We observed that by controlling the percolation threshold of the polymer semiconductor, the blend film became strain sensitive, with a gauge factor of 5.75 x 105 at 100% strain in a …
Emergent Functional Behaviour Of Humic Substances Perceived As Complex Labile Aggregates Of Small Organic Molecules And Oligomers, Robert L. Cook
Emergent Functional Behaviour Of Humic Substances Perceived As Complex Labile Aggregates Of Small Organic Molecules And Oligomers, Robert L. Cook
Faculty Publications
The structural organisation of humic substances (HS) has been a central question of earth sciences for several decades. The latest experimental results have led to the recognition of HS as complex mixtures of small molecules and oligomers. We investigate the correlation between the chemical composition of HS, perceived as labile aggregates, and the emergent functions. Computational modelling was used to help to understand the processes and mechanisms on the molecular scale that occur in different fractions of the HS, fulvic acids (FA) and humic acids (HA), as they interact with metal ions and organic pollutants. The importance of non-covalent interactions …
Detection Of Chalk In Single Kernels Of Long-Grain Milled Rice Using Imaging And Visible/Near-Infrared Instruments, Christopher K. Addison
Detection Of Chalk In Single Kernels Of Long-Grain Milled Rice Using Imaging And Visible/Near-Infrared Instruments, Christopher K. Addison
Faculty Publications
Background and objectives To maintain the competitiveness of U.S. long-grain rice in U.S. and foreign markets, having translucent whole milled grain is critical. An objective technique to detect grain chalk, opaque areas in the grain, will provide breeders and industry with an effective tool for developing low-chalk varieties or agronomic practices that reduce chalk occurrence. Two instruments developed at the Center for Grain and Animal Health Research, U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS), a single-kernel near-infrared (SKNIR) tube instrument and a silicon-based light-emitting diode (SiLED) high-speed sorter, were compared with two commercially available imaging instruments, WinSEEDLE and SeedCount used …
Cross-Linked Poly(4-Vinylpyridine-N-Oxide) As A Polymer-Supported Oxygen Atom Transfer Reagent, Anna M. Bauer, Erin E. Ramey, Kjersti G. Oberle, Gretchen A. Fata, Chloe D. Hutchison, Christopher R. Turlington
Cross-Linked Poly(4-Vinylpyridine-N-Oxide) As A Polymer-Supported Oxygen Atom Transfer Reagent, Anna M. Bauer, Erin E. Ramey, Kjersti G. Oberle, Gretchen A. Fata, Chloe D. Hutchison, Christopher R. Turlington
Faculty Publications
Oxygen atom transfer (OAT) reagents are common in biological and industrial oxidation reactions. While many heterogeneous catalysts have been utilized in OAT reactions, heterogeneous OAT reagents have not been explored. Here, cross-linked poly(4-vinylpyridine-N-oxide), called x-PVP-N-oxide, was tested as a heterogeneous OAT reagent and its oxidation chemistry compared to its molecular counterpart, pyridine-N-oxide. The insoluble oxidant x-PVP-N-oxide demonstrated comparable reactivity to pyridine-N-oxide in direct oxidation reactions of phosphines and phosphites in acetonitrile, but x-PVP-N-oxide did not react in other solvents. The polymer backbone of x-PVP-N-oxide, however, allowed …
Experimental And Computational Electrochemistry Of Quinazolinespirohexadienone Molecular Switches – Differential Electrochromic Vs Photochromic Behavior, Eric W. Webb, Jonathan P. Moerdyk, Kyndra B. Sluiter, Benjamin J. Pollock, Amy L. Speelman, Eugene J. Lynch, William F. Polik, Jason G. Gillmore
Experimental And Computational Electrochemistry Of Quinazolinespirohexadienone Molecular Switches – Differential Electrochromic Vs Photochromic Behavior, Eric W. Webb, Jonathan P. Moerdyk, Kyndra B. Sluiter, Benjamin J. Pollock, Amy L. Speelman, Eugene J. Lynch, William F. Polik, Jason G. Gillmore
Faculty Publications
Our undergraduate research group has long focused on the preparation and investigation of electron-deficient analogs of the perimidinespirohexadienone (PSHD) family of photochromic molecular switches for potential application as "photochromic photooxidants" for gating sensitivity to photoinduced charge transfer. We previously reported the photochemistry of two closely related and more reducible quinazolinespirohexadienones (QSHDs), wherein the naphthalene of the PSHD is replaced with a quinoline. In the present work, we report our investigation of the electrochemistry of these asymmetric QSHDs. In addition to the short wavelength and photochromic long-wavelength isomers, we have found that a second, distinct long-wavelength isomer is produced electrochemically. This …
Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner
Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner
Faculty Publications
A novel sky-blue-emitting tripyrenylpyridine derivative, 2,4,6-tri(1-pyrenyl)-pyridine (2,4,6-TPP), has been synthesized using a Suzuki coupling reaction and compared with three previously reported isomeric dipyrenylpyridine (DPP) analogues (2,4-di(1 pyrenyl)pyridine (2,4-DPP), 2,6-di(1-pyrenyl)pyridine (2,6-DPP), and 3,5-di(1-pyrenyl)-pyridine (3,5-DPP)). 0 revealed by single-crystal X-ray analysis and computational simulations, all compounds possess highly twisted conformations in the solid state with interpyrene torsional angles of 42.3 degrees-57.2 degrees. These solid-state conformations and packing variations of pyrenylpyridines could be correlated to observed variations in physical characteristics such as photo/thermal stability and spectral properties, but showed only marginal influence on electrochemical properties. The novel derivative, 2,4,6-TPP, exhibited the lowest degree …
Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner
Pyrenylpyridines: Sky-Blue Emitters For Organic Light-Emitting Diodes, Thenahandi Prasanthi Deepthika De Silva, Sang Gill Youm, Isiah M. Warner
Faculty Publications
A novel sky-blue-emitting tripyrenylpyridine derivative, 2,4,6-tri(1-pyrenyl)-pyridine (2,4,6-TPP), has been synthesized using a Suzuki coupling reaction and compared with three previously reported isomeric dipyrenylpyridine (DPP) analogues (2,4-di(1 pyrenyl)pyridine (2,4-DPP), 2,6-di(1-pyrenyl)pyridine (2,6-DPP), and 3,5-di(1-pyrenyl)-pyridine (3,5-DPP)). 0 revealed by single-crystal X-ray analysis and computational simulations, all compounds possess highly twisted conformations in the solid state with interpyrene torsional angles of 42.3 degrees-57.2 degrees. These solid-state conformations and packing variations of pyrenylpyridines could be correlated to observed variations in physical characteristics such as photo/thermal stability and spectral properties, but showed only marginal influence on electrochemical properties. The novel derivative, 2,4,6-TPP, exhibited the lowest degree …
Rompi-Cdsa: Ring-Opening Metathesis Polymerization-Induced Crystallization-Driven Self-Assembly Of Metallo-Block Copolymers, Ye Sha, Md Anisur Rahman, Tianyu Zhu, Yujin Cha, C Wayne Mcalister, Chuanbing Tang
Rompi-Cdsa: Ring-Opening Metathesis Polymerization-Induced Crystallization-Driven Self-Assembly Of Metallo-Block Copolymers, Ye Sha, Md Anisur Rahman, Tianyu Zhu, Yujin Cha, C Wayne Mcalister, Chuanbing Tang
Faculty Publications
Polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are among the most prevailing methods for block copolymer self-assembly. Taking the merits of scalability of PISA and dimension control of CDSA, we report one-pot synchronous PISA and CDSA ring-opening metathesis polymerization (ROMP) to prepare nano-objects based on a crystalline poly(ruthenocene) motif. We denote this self-assembly methodology as ROMPI-CDSA to enable a simple, yet robust approach for the preparation of functional nanomaterials.
Preface To Special Issue “International Year Of The Periodic Table: From Mendeleev To Cluster Chemistry”, Richard D. Adams, Boon Teo, Vladimir P. Fedin
Preface To Special Issue “International Year Of The Periodic Table: From Mendeleev To Cluster Chemistry”, Richard D. Adams, Boon Teo, Vladimir P. Fedin
Faculty Publications
No abstract provided.
Fisetin, A 3,7,3 ',4 '-Tetrahydroxyflavone Inhibits The Pi3k/Akt/Mtor And Mapk Pathways And Ameliorates Psoriasis Pathology In 2d And 3d Organotypic Human Inflammatory Skin Models, Konstantin G. Kousoulas
Fisetin, A 3,7,3 ',4 '-Tetrahydroxyflavone Inhibits The Pi3k/Akt/Mtor And Mapk Pathways And Ameliorates Psoriasis Pathology In 2d And 3d Organotypic Human Inflammatory Skin Models, Konstantin G. Kousoulas
Faculty Publications
Psoriasis is a chronic immune-mediated skin disease that involves the interaction of immune and skin cells, and is characterized by cytokine-driven epidermal hyperplasia, deviant differentiation, inflammation, and angiogenesis. Because the available treatments for psoriasis have significant limitations, dietary products are potential natural sources of therapeutic molecules, which can repair the molecular defects associated with psoriasis and could possibly be developed for its management. Fisetin (3,7,3 ',4 '-tetrahydroxyflavone), a phytochemical naturally found in pigmented fruits and vegetables, has demonstrated proapoptotic and antioxidant effects in several malignancies. This study utilized biochemical, cellular, pharmacological, and tissue engineering tools to characterize the effects of …
Approaches For Sample Characterization And Lithography With Nanoparticles Using Modes Of Scanning Probe Microscopy, Jayne C. Garno, Temitope O. Jegede, Kathryn B. Mckee, Melissia Porter, Autumn E. Webb, Jin Gyun Lee, Neepa Mk Kuruppu Arachchige, Justin R. Ragains, Noémie Elgrishi
Approaches For Sample Characterization And Lithography With Nanoparticles Using Modes Of Scanning Probe Microscopy, Jayne C. Garno, Temitope O. Jegede, Kathryn B. Mckee, Melissia Porter, Autumn E. Webb, Jin Gyun Lee, Neepa Mk Kuruppu Arachchige, Justin R. Ragains, Noémie Elgrishi
Faculty Publications
Measurement and imaging modes of scanning probe microscopy (SPM) have been routinely applied for characterizing systems of nanoparticles; however the evolution of fabrication methods to prepare arrangements of nanoparticles remains a challenge. Reproducible fabrication of surface structures which integrate nanoparticles within ultra-small patterns will require innovative approaches to achieve high throughput and precision. Strategies for nanoscale lithography have been introduced for preparing defined arrangements of nanoparticles on surfaces based on physical or chemical interactions. For example, physisorption was employed for attaching nanoparticles based on colloidal lithography and site-directed assembly. Microfabricated atomic force microscope (AFM) tips with capillary channels have been …
A New Magnetic Topological Quantum Material Candidate By Design, Weiwei Xie, Xin Gui
A New Magnetic Topological Quantum Material Candidate By Design, Weiwei Xie, Xin Gui
Faculty Publications
Magnetism, when combined with an unconventional electronic band structure, can give rise to forefront electronic properties such as the quantum anomalous Hall effect, axion electrodynamics, and Majorana fermions. Here we report the characterization of high-quality crystals of EuSn2P2, a new quantum material specifically designed to engender unconventional electronic states plus magnetism. EuSn2P2 has a layered, Bi2Te3-type structure. Ferromagnetic interactions dominate the Curie-Weiss susceptibility, but a transition to antiferromagnetic ordering occurs near 30 K. Neutron diffraction reveals that this is due to two-dimensional ferromagnetic spin alignment within individual Eu layers and antiferromagnetic alignment between layers-this magnetic state surrounds the Sn-P layers …
Melt Electrospinning Designs For Nanofiber Fabrication For Different Applications, Yasseen S. Ibrahim, Essraa A. Hussein, Moustafa M. Zagho, Ghada G. Abdo, Ahmed A. Elzatahry
Melt Electrospinning Designs For Nanofiber Fabrication For Different Applications, Yasseen S. Ibrahim, Essraa A. Hussein, Moustafa M. Zagho, Ghada G. Abdo, Ahmed A. Elzatahry
Faculty Publications
Nanofibers have been attracting growing attention owing to their outstanding physicochemical and structural properties as well as diverse and intriguing applications. Electrospinning has been known as a simple, flexible, and multipurpose technique for the fabrication of submicro scale fibers. Throughout the last two decades, numerous investigations have focused on the employment of electrospinning techniques to improve the characteristics of fabricated fibers. This review highlights the state of the art of melt electrospinning and clarifies the major categories based on multitemperature control, gas assist, laser melt, coaxial, and needleless designs. In addition, we represent the effect of melt electrospinning process parameters …
A High-Spin Ground-State Donor-Acceptor Conjugated Polymer, Alex E. London, H. Chen, M.A. Sabuj, Joshua Tropp, M. Saghayezhian, Naresh Eedugurala, B.A. Zhang, Y. Liu, Xiaodan Gu, B.M. Wong, N. Rai, M.K. Bowman, Jason D. Azoulay
A High-Spin Ground-State Donor-Acceptor Conjugated Polymer, Alex E. London, H. Chen, M.A. Sabuj, Joshua Tropp, M. Saghayezhian, Naresh Eedugurala, B.A. Zhang, Y. Liu, Xiaodan Gu, B.M. Wong, N. Rai, M.K. Bowman, Jason D. Azoulay
Faculty Publications
Interest in high-spin organic materials is driven by opportunities to enable far-reaching fundamental science and develop technologies that integrate light element spin, magnetic, and quantum functionalities. Although extensively studied, the intrinsic instability of these materials complicates synthesis and precludes an understanding of how fundamental properties associated with the nature of the chemical bond and electron pairing in organic materials systems manifest in practical applications. Here, we demonstrate a conjugated polymer semiconductor, based on alternating cyclopentadithiophene and thiadiazoloquinoxaline units, that is a ground-state triplet in its neutral form. Electron paramagnetic resonance and magnetic susceptibility measurements are consistent with a high-to-low spin …
Molecular Packing Control Enables Excellent Performance And Mechanical Property Of Blade-Cast All-Polymer Solar Cells, Baojun Lin, Lin Zhang, Heng Zhao, Xianbin Xu, Ke Zhou, Song Zhang, Lu Guo, Baobing Fan, Lei Zhang, Hongping Yan, Xiaodan Gu, Lei Ying, Fei Huang, Yong Cao, Wei Ma
Molecular Packing Control Enables Excellent Performance And Mechanical Property Of Blade-Cast All-Polymer Solar Cells, Baojun Lin, Lin Zhang, Heng Zhao, Xianbin Xu, Ke Zhou, Song Zhang, Lu Guo, Baobing Fan, Lei Zhang, Hongping Yan, Xiaodan Gu, Lei Ying, Fei Huang, Yong Cao, Wei Ma
Faculty Publications
All-polymer solar cells (all-PSCs) are the most promising power generators for flexible and portable devices due to excellent morphology stability and outstanding mechanical property. Previous work indicates high crystallinity is beneficial to device performance but detrimental to mechanical property, therefore identifying the optimized ratio between crystalline and amorphous domains becomes important. In this work, we demonstrated highly efficient and mechanically robust all-PSCs by blade-coating technology in ambient environment based on PTzBI:N2200 system. By controlling the aggregation in solution state and ultrafast film formation process, a weakly ordered molecular packing morphology as well as small phase separation is obtained, which leads …
A High-Spin Ground-State Donor-Acceptor Conjugated Polymer, A.E. London, H. Chen, M.A. Sabuj, J. Tropp, M. Saghayezhian, N. Eedugurala, B.A. Zhang, Y. Liu, X. Gu, B.M. Wong, N. Rai, M.K. Bowman, J.D. Azoulay
A High-Spin Ground-State Donor-Acceptor Conjugated Polymer, A.E. London, H. Chen, M.A. Sabuj, J. Tropp, M. Saghayezhian, N. Eedugurala, B.A. Zhang, Y. Liu, X. Gu, B.M. Wong, N. Rai, M.K. Bowman, J.D. Azoulay
Faculty Publications
Interest in high-spin organic materials is driven by opportunities to enable far-reaching fundamental science and develop technologies that integrate light element spin, magnetic, and quantum functionalities. Although extensively studied, the intrinsic instability of these materials complicates synthesis and precludes an understanding of how fundamental properties associated with the nature of the chemical bond and electron pairing in organic materials systems manifest in practical applications. Here, we demonstrate a conjugated polymer semiconductor, based on alternating cyclopentadithiophene and thiadiazoloquinoxaline units, that is a ground-state triplet in its neutral form. Electron paramagnetic resonance and magnetic susceptibility measurements are consistent with a high-to-low spin …
Generalizing Metallocene Mechanochemistry To Ruthenocene Mechanophores, Ye Sha, Yudi Zhang, Enhua Xu, C Wayne Mcalister, Tianyu Zhu, Stephen L. Craig, Chuanbing Tang
Generalizing Metallocene Mechanochemistry To Ruthenocene Mechanophores, Ye Sha, Yudi Zhang, Enhua Xu, C Wayne Mcalister, Tianyu Zhu, Stephen L. Craig, Chuanbing Tang
Faculty Publications
Recent reports have shown that ferrocene displays an unexpected combination of force-free stability and mechanochemical activity, as it acts as the preferred site of chain scission along the backbone of highly extended polymer chains. This observation raises the tantalizing question as to whether similar mechanochemical activity might be present in other metallocenes, and, if so, what features of metallocenes dictate their relative ability to act as mechanophores. In this work, we elucidate polymerization methodologies towards main-chain ruthenocene-based polymers and explore the mechanochemistry of ruthenocene. We find that ruthenocene, in analogy to ferrocene, acts as a highly selective site of main …
Low Molecular Weight Fluorescent Probes (Lmfps) To Detect The Group 12 Metal Triad, Ashley D. Johnson, Rose M. Curtis, Karl J. Wallace
Low Molecular Weight Fluorescent Probes (Lmfps) To Detect The Group 12 Metal Triad, Ashley D. Johnson, Rose M. Curtis, Karl J. Wallace
Faculty Publications
Fluorescence sensing, of d-block elements such as Cu2+, Fe3+, Fe2+, Cd2+, Hg2+, and Zn2+ has significantly increased since the beginning of the 21st century. These particular metal ions play essential roles in biological, industrial, and environmental applications, therefore, there has been a drive to measure, detect, and remediate these metal ions. We have chosen to highlight the low molecular weight fluorescent probes (LMFPs) that undergo an optical response upon coordination with the group 12 triad (Zn2+, Cd2+, and Hg2+), as these metals have …
The Lowest-Energy Isomer Of C2si2h4 Is A Bridged Ring: Reinterpretation Of The Spectroscopic Data Based On Dft And Coupled-Cluster Calculations, Jesse J. Lutz, Larry W. Burggraf
The Lowest-Energy Isomer Of C2si2h4 Is A Bridged Ring: Reinterpretation Of The Spectroscopic Data Based On Dft And Coupled-Cluster Calculations, Jesse J. Lutz, Larry W. Burggraf
Faculty Publications
The lowest-energy isomer of C2Si2H4 is determined by high-accuracy ab initio calculations to be the bridged four-membered ring 1,2-didehydro-1,3-disilabicyclo[1.1.0]butane (1), contrary to prior theoretical and experimental studies favoring the three-member ring silylsilacyclopropenylidene (2). These and eight other low-lying minima on the potential energy surface are characterized and ordered by energy using the CCSD(T) method with complete basis set extrapolation, and the resulting benchmark-quality set of relative isomer energies is used to evaluate the performance of several comparatively inexpensive approaches based on many-body perturbation theory and density functional theory (DFT). Double-hybrid DFT methods are found to …
Evidence For A Bind-Then-Bend Mechanism For Architectural Dna Binding Protein Ynhp6a, Manas Kumar Sarangi, Viktoriya Zvoda, Molly Nelson Holte, Nicole A. Becker, Justin Peters, L. James Maher Iii, Anjum Ansari
Evidence For A Bind-Then-Bend Mechanism For Architectural Dna Binding Protein Ynhp6a, Manas Kumar Sarangi, Viktoriya Zvoda, Molly Nelson Holte, Nicole A. Becker, Justin Peters, L. James Maher Iii, Anjum Ansari
Faculty Publications
The yeast Nhp6A protein (yNhp6A) is a member of the eukaryotic HMGB family of chromatin factors that enhance apparent DNA flexibility. yNhp6A binds DNA nonspecifically with nM affinity, sharply bending DNA by >60◦. It is not known whether the protein binds to unbent DNA and then deforms it, or if bent DNA conformations are ‘captured’ by protein binding. The former mechanism would be supported by discovery of conditions where unbent DNA is bound by yNhp6A. Here, we employed an array of conformational probes (FRET, fluorescence anisotropy, and circular dichroism) to reveal solution conditions in which an 18- base-pair DNA oligomer …
Ultra-Strong Long-Chain Polyamide Elastomers With Programmable Supramolecular Interactions And Oriented Crystalline Microstructures, Lingzhi Song, Tianyu Zhu, Liang Yuan, Jiangjun Zhou, Yaqiong Zhang, Zhongkai Wang, Chuanbing Tang
Ultra-Strong Long-Chain Polyamide Elastomers With Programmable Supramolecular Interactions And Oriented Crystalline Microstructures, Lingzhi Song, Tianyu Zhu, Liang Yuan, Jiangjun Zhou, Yaqiong Zhang, Zhongkai Wang, Chuanbing Tang
Faculty Publications
Polyamides are one of the most important polymers. Long-chain aliphatic polyamides could bridge the gap between traditional polyamides and polyethylenes. Here we report an approach to preparing sustainable ultra-strong elastomers from biomass-derived long-chain polyamides by thiol-ene addition copolymerization with diamide diene monomers. The pendant polar hydroxyl and non-polar butyrate groups between amides allow controlled programming of supramolecular hydrogen bonding and facile tuning of crystallization of polymer chains. The presence of thioether groups on the main chain can further induce metal–ligand coordination (cuprous-thioether). Unidirectional step-cycle tensile deformation has been applied to these polyamides and significantly enhances tensile strength to over 210 …
Multiplexed Paper Microfluidics For Titration And Detection Of Ingredients In Beverages, Manas Ranjan Gartia, Alisha Prasad
Multiplexed Paper Microfluidics For Titration And Detection Of Ingredients In Beverages, Manas Ranjan Gartia, Alisha Prasad
Faculty Publications
Food safety and access to systematic approaches for ensuring detection of food hazards is an important issue in most developing countries. With the arrival of paper-based analytical devices (mu PADs) as a promising, rapid, easy-to-use, and low-cost analytical tool, we demonstrated a simple microfluidic-based titration study for the analysis of packaged fruit juices. Similar, to the titration experiments using traditional glassware in chemistry laboratories, in this study the titration experiments were developed using paper microfluidics for the analysis of several analytes such as pH, vitamin C, sugars, and preservatives present in the packaged fruit juices. The allergen found commonly in …
Bioassay-Guided Isolation And Structure Elucidation Of Fungicidal And Herbicidal Compounds From Ambrosia Salsola (Asteraceae), Frank R. Fronczek
Bioassay-Guided Isolation And Structure Elucidation Of Fungicidal And Herbicidal Compounds From Ambrosia Salsola (Asteraceae), Frank R. Fronczek
Faculty Publications
The discovery of potent natural and ecofriendly pesticides is one of the focuses of the agrochemical industry, and plant species are a source of many potentially active compounds. We describe the bioassay-guided isolation of antifungal and phytotoxic compounds from the ethyl acetate extract of Ambrosia salsola twigs and leaves. With this methodology, we isolated and identified twelve compounds (four chalcones, six flavonols and two pseudoguaianolide sesquiterpene lactones). Three new chalcones were elucidated as (S)-beta-Hydroxy-2,3,4,6'-tetrahydroxy-5-methoxydihydrochalcone (salsolol A), (S)-beta-Hydroxy-2',4,4',6'-tetrahydroxy-3-methoxydihydrochalcone (salsolol B), and (R)-alpha, (R)-beta-Dihydroxy-2,3,4,4,6'-pentahydroxydihydrochalcone (salsolol C) together with nine known compounds: balanochalcone, six quercetin derivatives, confertin, and neoambrosin. Chemical structures were determined …
Large Fatty Acid-Derived Aβ42 Oligomers Form Ring-Like Assemblies, Wenhui Xu, Dexter N. Dean, Kelli A. Stockmal, Sarah E. Morgan, Ulrich H.E. Hansmann, Vijayaraghavan Rangachari
Large Fatty Acid-Derived Aβ42 Oligomers Form Ring-Like Assemblies, Wenhui Xu, Dexter N. Dean, Kelli A. Stockmal, Sarah E. Morgan, Ulrich H.E. Hansmann, Vijayaraghavan Rangachari
Faculty Publications
As the primary toxic species in the etiology of Alzheimer disease (AD) are low molecular weight oligomers of Aβ, it is crucial to understand the structure of Aβ oligomers for gaining molecular insights into AD pathology. We have earlier demonstrated that in the presence of fatty acids, Aβ42 peptides assemble as 12-24mer oligomers. These Large Fatty Acid-derived Oligomers (LFAOs) exist predominantly as 12mers at low and as 24mers at high concentrations. The 12mers are more neurotoxic than the 24mers and undergo self-replication, while the latter propagate to morphologically distinct fibrils with succinct pathological consequences. In order to glean into their …
Realization Of A Type-Ii Nodal-Line Semimetal In Mg3bi2, Weiwei Xie
Realization Of A Type-Ii Nodal-Line Semimetal In Mg3bi2, Weiwei Xie
Faculty Publications
Nodal-line semimetals (NLSs) represent a new type of topological semimetallic phase beyond Weyl and Dirac semimetals in the sense that they host closed loops or open curves of band degeneracies in the Brillouin zone. Parallel to the classification of type-I and type-II Weyl semimetals, there are two types of NLSs. The type-I NLS phase has been proposed and realized in many compounds, whereas the exotic type-II NLS phase that strongly violates Lorentz symmetry has remained elusive. First-principles calculations show that Mg3Bi2 is a material candidate for the type-II NLS. The band crossing is close to the Fermi level and exhibits …
Substrate-Dependent Photoconductivity Dynamics In A High-Efficiency Hybrid Perovskite Alloy, Ali Moeed Tirmzi, Jeffrey A. Christians, Ryan P. Dwyer, David T. Moore, John A. Marohn
Substrate-Dependent Photoconductivity Dynamics In A High-Efficiency Hybrid Perovskite Alloy, Ali Moeed Tirmzi, Jeffrey A. Christians, Ryan P. Dwyer, David T. Moore, John A. Marohn
Faculty Publications
Films of (FA0.79MA0.16Cs0.05)0.97Pb(I0.84Br0.16)2.97 were grown over TiO2, SnO2, indium tin oxide (ITO), and NiO. Film conductivity was interrogated by measuring the in-phase and out-of-phase forces acting between the film and a charged microcantilever. We followed the films’ conductivity versus time, frequency, light intensity, and temperature (233−312 K). Perovskite conductivity was high and light-independent over ITO and NiO. Over TiO2 and SnO2, the conductivity was low in the dark,increased with light intensity, and persisted for 10’s of seconds after the light …
Exposure Characterization Of Haloacetic Acids In Humans For Exposure And Risk Assessment Applications: An Exploratory Study, Shahid Parvez, Jeffrey L. Ashby, Susana Y. Kimura, Susan D. Richardson
Exposure Characterization Of Haloacetic Acids In Humans For Exposure And Risk Assessment Applications: An Exploratory Study, Shahid Parvez, Jeffrey L. Ashby, Susana Y. Kimura, Susan D. Richardson
Faculty Publications
Disinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono-, di-, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels …