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Full-Text Articles in Physical Sciences and Mathematics

Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner Dec 2019

Importance Of Refractory Ligands And Their Photodegradation For Iron Oceanic Inventories And Cycling, Christel Hassler, Damien Cabanes, Sonia Blanco-Ameijeiras, Sylvia G. Sander, Ronald Benner

Faculty Publications

Iron is an essential micronutrient that limits primary production in up to 40% of the surface ocean and influences carbon dioxide uptake and climate change. Dissolved iron is mostly associated with loosely characterised organic molecules, called ligands, which define key aspects of the iron cycle such as its residence time, distribution and bioavailability to plankton. Models based on in situ ligand distributions and the behaviour of purified compounds include long-lived ligands in the deep ocean, bioreactive ligands in the surface ocean and photochemical processes as important components of the iron cycle. Herein, we further characterise biologically refractory ligands in dissolved …


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 Sep 2019

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.


A Comparison Of The Trojan Y Chromosome Strategy To Harvesting Models For Eradication Of Non-Native Species, Jingjing Lyu, Pamela J. Schofield, Kristen M. Reaver, Matthew Beauregard, Rana D. Parshad Aug 2019

A Comparison Of The Trojan Y Chromosome Strategy To Harvesting Models For Eradication Of Non-Native Species, Jingjing Lyu, Pamela J. Schofield, Kristen M. Reaver, Matthew Beauregard, Rana D. Parshad

Faculty Publications

The Trojan Y Chromosome Strategy (TYC) is a promising eradication method for biological control of non-native species. The strategy works by manipulating the sex ratio of a population through the introduction of supermales that guarantee male offspring. In the current manuscript, we compare the TYC method with a pure harvesting strategy. We also analyze a hybrid harvesting model that mirrors the TYC strategy. The dynamic analysis leads to results on stability of solutions and bifurcations of the model. Several conclusions about the different strategies are established via optimal control methods. In particular, the results affirm that either a pure harvesting …


Subsurface Mimo: A Beamforming Design In Internet Of Underground Things For Digital Agriculture Applications, Abdul Salam Aug 2019

Subsurface Mimo: A Beamforming Design In Internet Of Underground Things For Digital Agriculture Applications, Abdul Salam

Faculty Publications

In underground (UG) multiple-input and multiple-output (MIMO), the transmit beamforming is used to focus energy in the desired direction. There are three different paths in the underground soil medium through which the waves propagates to reach at the receiver. When the UG receiver receives a desired data stream only from the desired path, then the UG MIMO channel becomes three path (lateral, direct, and reflected) interference channel. Accordingly, the capacity region of the UG MIMO three path interference channel and degrees of freedom (multiplexing gain of this MIMO channel requires careful modeling). Therefore, expressions are required for the degree of …


Large And Small Data Blow-Up Solutions In The Trojan Y Chromosome Model, Rana D. Parshad, Matthew Beauregard, Eric M. Takyi, Thomas Griffin, Landrey Bobo Jul 2019

Large And Small Data Blow-Up Solutions In The Trojan Y Chromosome Model, Rana D. Parshad, Matthew Beauregard, Eric M. Takyi, Thomas Griffin, Landrey Bobo

Faculty Publications

The Trojan Y Chromosome Strategy (TYC) is an extremely well investigated biological control method for controlling invasive populations with an XX-XY sex determinism. In [35, 36] various dynamical properties of the system are analyzed, including well posedness, boundedness of solutions, and conditions for extinction or recovery. These results are derived under the assumption of positive solutions. In the current manuscript, we show that if the introduction rate of trojan fish is zero, under certain large data assumptions, negative solutions are possible for the male population, which in turn can lead to finite time blow-up in the female and male populations. …


Experimental Evidence Supportive Of The Quantum Dna Model, F. Matthew Mihelic May 2019

Experimental Evidence Supportive Of The Quantum Dna Model, F. Matthew Mihelic

Faculty Publications

The DNA molecule can be modeled as a quantum logic processor in which electron spin qubits are held coherently in each nucleotide in a logically and thermodynamically reversible enantiomeric symmetry, and can be coherently conducted along the pi-stacking interactions of aromatic nucleotide bases, while simultaneously being spin-filtered via the helicity of the DNA molecule. Entangled electron pairs can be separated by that spin-filtering, held coherently at biological temperatures in the topologically insulated nucleotide quantum gates, and incorporated into separate DNA strands during DNA replication. Two separate DNA strands that share quantum entangled electrons can be mitotically divided into individual cells, …


Generalizing Metallocene Mechanochemistry To Ruthenocene Mechanophores, Ye Sha, Yudi Zhang, Enhua Xu, C Wayne Mcalister, Tianyu Zhu, Stephen L. Craig, Chuanbing Tang Apr 2019

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 …


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 Mar 2019

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 …


A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak Feb 2019

A Theoretical Model Of Underground Dipole Antennas For Communications In Internet Of Underground Things, Abdul Salam, Mehmet C. Vuran, Xin Dong, Christos Argyropoulos, Suat Irmak

Faculty Publications

The realization of Internet of Underground Things (IOUT) relies on the establishment of reliable communication links, where the antenna becomes a major design component due to the significant impacts of soil. In this paper, a theoretical model is developed to capture the impacts of change of soil moisture on the return loss, resonant frequency, and bandwidth of a buried dipole antenna. Experiments are conducted in silty clay loam, sandy, and silt loam soil, to characterize the effects of soil, in an indoor testbed and field testbeds. It is shown that at subsurface burial depths (0.1-0.4m), change in soil moisture impacts …


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 Feb 2019

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 …


Betting & Hierarchy In Paleontology, Leonard Finkelman Jan 2019

Betting & Hierarchy In Paleontology, Leonard Finkelman

Faculty Publications

In his Rock, Bone, and Ruin: An Optimist’s Guide to the Historical Sciences, Adrian Currie argues that historical scientists should be optimistic about success in reconstructing the past on the basis of future research. This optimism follows in part from examples of success in paleontology. I argue that paleontologists’ success in these cases is underwritten by the hierarchical nature of biological information: extinct organisms have extant analogues at various levels of taxonomic, ecological, and physiological hierarchies, and paleontologists are adept at exploiting analogies within one informational hierarchy to infer information in another. On this account, fossils serve the role …


Crossed Tracks: Mesolimulus, Archaeopteryx, And The Nature Of Fossils, Leonard Finkelman Jan 2019

Crossed Tracks: Mesolimulus, Archaeopteryx, And The Nature Of Fossils, Leonard Finkelman

Faculty Publications

Organisms leave a variety of traces in the fossil record. Among these traces, vertebrate and invertebrate paleontologists conventionally recognize a distinction between the remains of an organism’s phenotype (body fossils) and the remains of an organism’s life activities (trace fossils). The same convention recognizes body fossils as biological structures and trace fossils as geological objects. This convention explains some curious practices in the classification, as with the distinction between taxa for trace fossils and for tracemakers. I consider the distinction between “parallel taxonomies,” or parataxonomies, which privileges some kinds of fossil taxa as “natural” and others as “artificial.” The motivations …


Effectiveness Of Plant Species For Removing Atmospheric Ammonia, Marife B. Anunciado, Sheryll B. Jerez, Hans Williams, Joey Bray, Dean W. Coble, Rena Saito Jan 2019

Effectiveness Of Plant Species For Removing Atmospheric Ammonia, Marife B. Anunciado, Sheryll B. Jerez, Hans Williams, Joey Bray, Dean W. Coble, Rena Saito

Faculty Publications

Six plant species of Yaupon, Eastern red cedar, American holly, Arizona cypress, Arborvitae and Roughleaf dogwood were utilized to determine their effectiveness in the removal of atmospheric ammonia. All species were exposed to three ammonia levels (1, 5 and 10 ppm) in an environmental chamber. Foliar ammonia content was quantified using an enzymatic technique. The effects of exposure to ammonia on the physiological responses (e.g. photosynthetic activity, stomatal conductance, and transpiration rate) of plants in ambient condition were also determined using an open design photosynthetic gas exchange system. Foliar ammonia content was significantly different among the six plant species (p<0.0001) with Eastern red cedar exhibiting the highest content. The physiological responses differed significantly depending on the plant species and the ammonia treatment level. The photosynthetic response of plants to the presence of ammonia was mixed. At low exposure level, all species except Arborvitae had decreased photosynthetic activity, reducing by as much as 44.5% for Yaupon. At the highest concentration, however, Yaupon’s photosynthetic activity improved by about 10%. Exposure to ammonia caused increased stomatal conductance and transpiration rate on American holly and Arizona cypress, making them more susceptible to water loss.


Move It Or Lose It: Interspecific Variation In Risk Response Of Pond-Breeding Anurans, Philip Matich, Christopher M. Schalk Jan 2019

Move It Or Lose It: Interspecific Variation In Risk Response Of Pond-Breeding Anurans, Philip Matich, Christopher M. Schalk

Faculty Publications

Changes in behavior are often the proximate response of animals to human disturbance, with variability in tolerance levels leading some species to exhibit striking shifts in life history, fitness, and/or survival. Thus, elucidating the effects of disturbance on animal behavior, and how this varies among taxonomically similar species with inherently different behaviors and life histories is of value for management and conservation. We evaluated the risk response of three anuran species—southern leopard frog (Lithobates sphenocephalus), Blanchard’s cricket frog (Acris blanchardi), and green tree frog (Hyla cinerea)—to determine how differences in microhabitat use (arboreal vs …


Correlates Of Snake Entanglement In Erosion Control Blankets, Sarah E. Ebert, Kasey L. Jobe, Christopher M. Schalk, Daniel Saenz, Cory K. Adams, Christopher E. Comer Jan 2019

Correlates Of Snake Entanglement In Erosion Control Blankets, Sarah E. Ebert, Kasey L. Jobe, Christopher M. Schalk, Daniel Saenz, Cory K. Adams, Christopher E. Comer

Faculty Publications

In road construction projects across the United States, erosion control methods (e.g., erosion control blankets [ECBs]), are mandated to stimulate seedbed regeneration and prevent soil loss. Previous reports have suggested that snakes are vulnerable to entanglement in ECBs. We conducted a literature review, field surveys, and an entanglement experiment to examine what factors increase a snake’s risk of ECB entanglement. Our literature review produced reports of 175 reptiles entangled in mesh products, 89.1% of which were snakes, with 43.6% of snake entanglements occurring in erosion control products. During our field surveys, we found 10 entangled snakes (n = 2 alive; …