Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Animals (3)
- Humans (3)
- Models (3)
- Models, Molecular (3)
- Molecular (3)
-
- Alzheimer Disease (2)
- Amino Acid Sequence (2)
- Amyloid beta-Peptides (2)
- Micelle (2)
- Molecular Dynamics Simulation (2)
- Protein Conformation (2)
- Rabbits (2)
- Raman (2)
- Spectrum Analysis (2)
- Spectrum Analysis, Raman (2)
- Synapses (2)
- Allosteric Regulation (1)
- Annexins (1)
- Antibacterial (1)
- Atherosclerosis (1)
- Au nanoparticle (1)
- Autocatalytic kinetics (1)
- Avidin (1)
- BN Heterocycles • Formazanate Ligands • Redox Chemistry • Boron Chemistry • Stable Radicals (1)
- Binding Sites (1)
- Binding affinity (1)
- Biocatalysis (1)
- Butyl rubber (1)
- CEH (1)
- CO oxidation (1)
Articles 1 - 30 of 35
Full-Text Articles in Physical Sciences and Mathematics
Changes In Enzyme Structural Dynamics Studied By Hydrogen Exchange-Mass Spectrometry: Ligand Binding Effects Or Catalytically Relevant Motions?, Courtney S Fast, Siavash Vahidi, Lars Konermann
Changes In Enzyme Structural Dynamics Studied By Hydrogen Exchange-Mass Spectrometry: Ligand Binding Effects Or Catalytically Relevant Motions?, Courtney S Fast, Siavash Vahidi, Lars Konermann
Chemistry Publications
It is believed that enzyme catalysis is facilitated by conformational dynamics of the protein scaffold that surrounds the active site, yet the exact nature of catalytically relevant protein motions remains largely unknown. Hydrogen/deuterium exchange (HDX) mass spectrometry (MS) reports on backbone H-bond fluctuations. HDX/MS thus represents a promising avenue for probing the relationship between enzyme dynamics and catalysis. A seemingly straightforward strategy for such studies involves comparative measurements during substrate turnover and in the resting state. We examined the feasibility of this approach using rabbit muscle pyruvate kinase (rM1-PK) which catalyzes the conversion of phosphoenolpyruvate and Mg-ADP to pyruvate and …
Effect Of Counter Ions On The Self-Assembly Of Polystyrene-Polyphosphonium Block Copolymers, Benjamin Hisey, Jasmine V. Buddingh, Elizabeth R. Gillies, Paul J. Ragogna
Effect Of Counter Ions On The Self-Assembly Of Polystyrene-Polyphosphonium Block Copolymers, Benjamin Hisey, Jasmine V. Buddingh, Elizabeth R. Gillies, Paul J. Ragogna
Chemistry Publications
The ability to manipulate block copolymers on the nanoscale has led to many scientific and technological advances. These include nano-scale ordered bulk and thin films and also solution phase components, these are promising materials for making smaller ordered electronics, selective membranes, and also biomedical applications. The ability to manipulate block copolymer material architectures on such small scales has risen from thorough investigations into the properties that affect the architectures. Polyelectrolytes are an important class of polymers that are used to make amphiphilic block copolymers. In this context the authors synthesized polystyrene-b-polyphosphonium block copolymers with different anions coordinated to …
1,6-Diphenyl-1,3,5-Hexatriene (Dph) As A Novel Matrix For Maldi Ms Imaging Of Fatty Acids, Phospholipids, And Sulfatides In Brain Tissues., Hanadi Ibrahim, Kristina Jurcic, Jasmine S-H Wang, Shawn N Whitehead, Ken K-C Yeung
1,6-Diphenyl-1,3,5-Hexatriene (Dph) As A Novel Matrix For Maldi Ms Imaging Of Fatty Acids, Phospholipids, And Sulfatides In Brain Tissues., Hanadi Ibrahim, Kristina Jurcic, Jasmine S-H Wang, Shawn N Whitehead, Ken K-C Yeung
Chemistry Publications
1,6-Diphenyl-1,3,5-hexatriene (DPH) is a commonly used fluorescence probe for studying cell membrane-lipids due to its affinity toward the acyl chains in the phospholipid bilayers. In this work, we investigated its use in matrix-assisted laser desorption/ionization (MALDI) as a new matrix for mass spectrometry imaging (MSI) of mouse and rat brain tissue. DPH exhibits very minimal matrix-induced background signals for the analysis of small molecules (below m/z of 1000). In the negative ion mode, DPH permits the highly sensitive detection of small fatty acids (m/z 200-350) as well as a variety of large lipids up to m/z of 1000, including lyso-phospholipid, …
Tip-Enhanced Raman Spectroscopy Of Amyloid Β At Neuronal Spines., Mohammadali Tabatabaei, Fabiana A Caetano, Farshid Pashee, Stephen S G Ferguson, François Lagugné-Labarthet
Tip-Enhanced Raman Spectroscopy Of Amyloid Β At Neuronal Spines., Mohammadali Tabatabaei, Fabiana A Caetano, Farshid Pashee, Stephen S G Ferguson, François Lagugné-Labarthet
Chemistry Publications
The early stages of Alzheimer's disease pathogenesis are thought to occur at the synapse level, since synapse loss can be directly correlated with memory dysfunction. Considerable evidence has suggested that amyloid beta (Aβ), a secreted proteolytic derivative of amyloid precursor protein, appears to be a critical factor in the early 'synaptic failure' that is observed in Alzheimer's disease pathogenesis. The identification of Aβ at neuronal spines with high spatial resolution and high surface specificity would facilitate unraveling the intricate effect of Aβ on synapse loss and its effect on neighboring neuronal connections. Here, tip-enhanced Raman spectroscopy was used to map …
Tip-Enhanced Raman Spectroscopy Of Amyloid Β At Neuronal Spines., Mohammadali Tabatabaei, Fabiana A Caetano, Farshid Pashee, Stephen S G Ferguson, François Lagugné-Labarthet
Tip-Enhanced Raman Spectroscopy Of Amyloid Β At Neuronal Spines., Mohammadali Tabatabaei, Fabiana A Caetano, Farshid Pashee, Stephen S G Ferguson, François Lagugné-Labarthet
Chemistry Publications
The early stages of Alzheimer's disease pathogenesis are thought to occur at the synapse level, since synapse loss can be directly correlated with memory dysfunction. Considerable evidence has suggested that amyloid beta (Aβ), a secreted proteolytic derivative of amyloid precursor protein, appears to be a critical factor in the early 'synaptic failure' that is observed in Alzheimer's disease pathogenesis. The identification of Aβ at neuronal spines with high spatial resolution and high surface specificity would facilitate unraveling the intricate effect of Aβ on synapse loss and its effect on neighboring neuronal connections. Here, tip-enhanced Raman spectroscopy was used to map …
Cytochrome C As A Peroxidase: Activation Of The Precatalytic Native State By H, Victor Yin, Gary S Shaw, Lars Konermann
Cytochrome C As A Peroxidase: Activation Of The Precatalytic Native State By H, Victor Yin, Gary S Shaw, Lars Konermann
Chemistry Publications
In addition to serving as respiratory electron shuttle, ferri-cytochrome c (cyt c) acts as a peroxidase; i.e., it catalyzes the oxidation of organic substrates by H2O2. This peroxidase function plays a key role during apoptosis. Typical peroxidases have a five-coordinate heme with a vacant distal coordination site that permits the iron center to interact with H2O2. In contrast, native cyt c is six-coordinate, as the distal coordination site is occupied by Met80. It thus seems counterintuitive that native cyt c would exhibit peroxidase activity. The current work scrutinizes the origin of this …
Dendritic Plasmonics For Mid-Infrared Spectroscopy, Francois Lagugne-Labarthet, Gregory Q. Wallace, Hayden C. Foy, Scott M. Rosendahl
Dendritic Plasmonics For Mid-Infrared Spectroscopy, Francois Lagugne-Labarthet, Gregory Q. Wallace, Hayden C. Foy, Scott M. Rosendahl
Chemistry Publications
Metallic nanostructures that exhibit tailored optical resonances spanning from the near to mid-infrared spectral range are of particular interest for spectroscopic and optical measurements in these spectral domains that can benefit from localized surface-enhancement effects. Plasmon resonances shifted in the near or mid-infrared range could be used to further enhance the excitation and/or the emission of an optical process. Surface-enhanced infrared absorption (SEIRA) is one of such processes and can particularly benefit from plasmon-enhanced local fields yielding an increase in sensitivity towards the detection of an analyte. Herein, we have fabricated a series of gold dendritic nanostructures, prepared by electron-beam …
Thermo-Responsive Self-Immolative Nanoassemblies: Direct And Indirect Triggering, Bo Fan, John F. Trant, Gauvin Hemery, Olivier Sandre, Elizabeth R. Gillies
Thermo-Responsive Self-Immolative Nanoassemblies: Direct And Indirect Triggering, Bo Fan, John F. Trant, Gauvin Hemery, Olivier Sandre, Elizabeth R. Gillies
Chemistry Publications
A thermo-responsive end-cap based on a retro-Diels-Alder and subsequent furan elimination reaction was developed. It was used to cap poly(ethyl glyoxylate), allowing end-to-end depolymerization upon thermal triggering. Using block copolymers, thermo-responsive micelles and vesicles were prepared and shown to disassemble upon heating. Thermal degradation could also be triggered indirectly by magnetic field hyperthermia after incorporation of iron oxide nanoparticles into the assemblies.
Aluminum Complexes Of N2o23‒ Formazanate Ligands Supported By Phosphine Oxide Donors, Ryan Maar, Amir Rabiee Kenaree, Ruizhong Zhang, Yichen Tao, Benjamin D. Katzman, Viktor N. Staroverov, Zhifeng Ding, Joe Gilroy
Aluminum Complexes Of N2o23‒ Formazanate Ligands Supported By Phosphine Oxide Donors, Ryan Maar, Amir Rabiee Kenaree, Ruizhong Zhang, Yichen Tao, Benjamin D. Katzman, Viktor N. Staroverov, Zhifeng Ding, Joe Gilroy
Chemistry Publications
The synthesis and characterization of a new family of phosphine-oxide-supported aluminum formazanate complexes (7a, 7b, 8a, 9a) are reported. X-ray diffraction studies revealed that the aluminum atoms in the complexes adopt an octahedral geometry in the solid state. The equatorial positions are occupied by an N2O23‒ formazanate ligand, and the axial positions are occupied by L-type phosphine oxide donors. UV-vis absorption spectroscopy revealed that the complexes were strongly absorbing (ε ~ 30,000 M‒1 cm‒1) between 500 and 700 nm. The absorption maxima in this region were simulated using …
Boron Difluoride Adducts Of A Flexidentate Pyridine-Substituted Formazanate Ligand: Property Modulation Via Protonation And Coordination Chemistry, Stephanie M. Barbon, Jasmine V. Buddingh, Ryan R. Maar, Joe Gilroy
Boron Difluoride Adducts Of A Flexidentate Pyridine-Substituted Formazanate Ligand: Property Modulation Via Protonation And Coordination Chemistry, Stephanie M. Barbon, Jasmine V. Buddingh, Ryan R. Maar, Joe Gilroy
Chemistry Publications
The synthesis and characterization of a flexidentate pyridine-substituted formazanate ligand and its boron difluoride adducts, formed via two different coordination modes of the title ligand, are described. The first adduct adopted a structure that was typical of other boron difluoride adducts of triarylformazanate ligands and contained a free pyridine subsituent, while the second was formed via chelation of nitrogen atoms from the formazanate backbone and the pyridine substituent. Stepwise protonation of the pydridine-functionalized adduct, which is essentially non-emissive, resulted in a significant increase in the fluorescence quantum yield up to a maximum of 18%, prompting study of this adduct as …
Addressing A Common Misconception: Ammonium Acetate As Neutral Ph "Buffer" For Native Electrospray Mass Spectrometry., Lars Konermann
Addressing A Common Misconception: Ammonium Acetate As Neutral Ph "Buffer" For Native Electrospray Mass Spectrometry., Lars Konermann
Chemistry Publications
Native ESI-MS involves the transfer of intact proteins and biomolecular complexes from solution into the gas phase. One potential pitfall is the occurrence of pH-induced changes that can affect the analyte while it is still surrounded by solvent. Most native ESI-MS studies employ neutral aqueous ammonium acetate solutions. It is a widely perpetuated misconception that ammonium acetate buffers the analyte solution at neutral pH. By definition, a buffer consists of a weak acid and its conjugate weak base. The buffering range covers the weak acid pKa ± 1 pH unit. NH4+ and CH3-COO- are …
Molecular Dynamics Simulations On Gas-Phase Proteins With Mobile Protons: Inclusion Of All-Atom Charge Solvation., Lars Konermann
Molecular Dynamics Simulations On Gas-Phase Proteins With Mobile Protons: Inclusion Of All-Atom Charge Solvation., Lars Konermann
Chemistry Publications
Molecular dynamics (MD) simulations have become a key tool for examining the properties of electrosprayed protein ions. Traditional force fields employ static charges on titratable sites, whereas in reality, protons are highly mobile in gas-phase proteins. Earlier studies tackled this problem by adjusting charge patterns during MD runs. Within those algorithms, proton redistribution was subject to energy minimization, taking into account electrostatic and proton affinity contributions. However, those earlier approaches described (de)protonated moieties as point charges, neglecting charge solvation, which is highly prevalent in the gas phase. Here, we describe a mobile proton algorithm that considers the electrostatic contributions from …
Calcium-Mediated Control Of S100 Proteins: Allosteric Communication Via An Agitator/Signal Blocking Mechanism., Yiming Xiao, Gary S Shaw, Lars Konermann
Calcium-Mediated Control Of S100 Proteins: Allosteric Communication Via An Agitator/Signal Blocking Mechanism., Yiming Xiao, Gary S Shaw, Lars Konermann
Chemistry Publications
Allosteric proteins possess dynamically coupled residues for the propagation of input signals to distant target binding sites. The input signals usually correspond to "effector is present" or "effector is not present". Many aspects of allosteric regulation remain incompletely understood. This work focused on S100A11, a dimeric EF-hand protein with two hydrophobic target binding sites. An annexin peptide (Ax) served as the target. Target binding is allosterically controlled by Ca2+ over a distance of ∼26 Å. Ca2+ promotes formation of a [Ca4 S100 Ax2] complex, where the Ax peptides are accommodated between helices III/IV and III'/IV'. …
(Co)Polymers Containing Boron Difluoride 3-Cyanoformazanate Complexes: Emission Enhancement Via Random Copolymerization, Joe Gilroy, Samantha Novoa
(Co)Polymers Containing Boron Difluoride 3-Cyanoformazanate Complexes: Emission Enhancement Via Random Copolymerization, Joe Gilroy, Samantha Novoa
Chemistry Publications
Ring-opening metathesis polymerization was used to produce polymers bearing an asymmetrically substituted boron difluoride 3-cyanoformazanate complex. The polymers were found to retain many of the unique characteristics of molecular boron difluoride complexes of 3-cyanoformazanates, including intense light absorption at ca. 560 nm and reversible electrochemical reductions implicating the radical anion and dianion forms of the formazanate complexes in the repeating unit of the polymer backbone. The polymers were also found to be emissive, with emission maxima centred at ca. 665 nm. The monomer employed in this study had a fluorescence quantum yield of 30%, while homopolymers were weakly emissive and …
Self-Healing Polyphosphonium Ionic Networks, Elizabeth Gillies, Tyler J. Cuthbert, Joshua J. Jadischke, John R. De Bruyn, Paul J. Ragogna, Elizabeth R. Gillies
Self-Healing Polyphosphonium Ionic Networks, Elizabeth Gillies, Tyler J. Cuthbert, Joshua J. Jadischke, John R. De Bruyn, Paul J. Ragogna, Elizabeth R. Gillies
Chemistry Publications
Self healing, ionically crosslinked networks were prepared from poly(acrylic acid) (PAA) and poly(triethyl(4-vinylbenzyl)phosphonium chloride (P-Et-P) and their properties were studied. Three different ratios of PAA/P-Et-P were incorporated into the networks by varying the addition orders of the components. Swelling of the networks increased with increasing NaCl concentration when they were immersed in aqueous solution. All networks retained their structural integrity in 0.1 M NaCl. Studies of the rheological and tensile properties of the networks swelled in 0.1 M NaCl showed that PAA>P-Et-Pexhibited high elongation and viscoelastic properties suitable for self-healing with a relaxation time of ~30 …
Structurally Diverse Boron-Nitrogen Heterocycles From An N2o23− Formazanate Ligand, Stephanie M. Barbon, Viktor N. Staroverov, Joe Gilroy
Structurally Diverse Boron-Nitrogen Heterocycles From An N2o23− Formazanate Ligand, Stephanie M. Barbon, Viktor N. Staroverov, Joe Gilroy
Chemistry Publications
Five new compounds comprised of unprecedented boron-nitrogen heterocycles have been isolated from a single reaction of a potentially tetradentate N2O23− formazanate ligand with BF3•OEt2 and NEt3. Optimized yields for each product were obtained through variation of experimental conditions and rationalized in terms of relative Gibbs free energies of the products as determined by electronic structure calculations. Chemical reduction of two of these compounds resulted in the formation of a stable anion, radical anion, and diradical dianion. Structural and electronic properties of this new family of redox-active heterocycles were characterized using UV-vis …
Structurally Diverse Boron-Nitrogen Heterocycles From An N2o23− Formazanate Ligand, Stephanie Barbon, Viktor Staroverov, Joe Gilroy
Structurally Diverse Boron-Nitrogen Heterocycles From An N2o23− Formazanate Ligand, Stephanie Barbon, Viktor Staroverov, Joe Gilroy
Chemistry Publications
Five new compounds comprised of unprecedented boron-nitrogen heterocycles have been isolated from a single reaction of a potentially tetradentate N2O23− formazanate ligand with BF3•OEt2 and NEt3. Optimized yields for each product were obtained through variation of experimental conditions and rationalized in terms of relative Gibbs free energies of the products as determined by electronic structure calculations. Chemical reduction of two of these compounds resulted in the formation of a stable anion, radical anion, and diradical dianion. Structural and electronic properties of this new family of redox-active heterocycles were characterized using UV-vis …
Catalytic Acceptorless Dehydrogenation Of Amines With Ru(PR2nR′2) And Ru(Dppp) Complexes, James M. Stubbs, Richard J. Hazlehurst, Paul D. Boyle, Johanna M. Blacquiere
Catalytic Acceptorless Dehydrogenation Of Amines With Ru(PR2nR′2) And Ru(Dppp) Complexes, James M. Stubbs, Richard J. Hazlehurst, Paul D. Boyle, Johanna M. Blacquiere
Chemistry Publications
[Ru(Cp)(PPh2NBn2)(MeCN)]PF6 (1; PPh2NBn2 = 1,5-benzyl-3,7-phenyl-1,5-diaza-3,7-diphosphacyclooctane) and [Ru(Cp)(dppp)(MeCN)]PF6 (2; dppp = 1,3-bis(diphenylphosphino)propane) are both active toward the acceptorless dehydrogenation of benzylamine (BnNH2) and N-heterocycles. The two catalysts have similar activities but different selectivities for dehydrogenation products. Independent synthesis of a [Ru(Cp)(PPh2NBn2)(NH2Bn)]PF6 adduct (3) reveals the presence of a hydrogen bond between the bound amine and the pendent base of the PPh2NBn2 ligand. Preliminary mechanistic studies reveal that the benzylamine adduct is not an on-cycle catalyst intermediate.
Design, Synthesis, And Characterization Of A Phosphine-Based Heterotrimetallic (M = Fe, Ru, W) Homopolymer, Joe Gilroy, Amir Rabiee Kenaree
Design, Synthesis, And Characterization Of A Phosphine-Based Heterotrimetallic (M = Fe, Ru, W) Homopolymer, Joe Gilroy, Amir Rabiee Kenaree
Chemistry Publications
An organometallic homopolymer containing three different metals per repeating unit was synthesized from an air- and moisture-stable secondary phosphine bearing ethylferrocene and ethylruthenocene groups. Hydrophosphination yielded a tertiary phosphine bearing an alcohol, which was then used to introduce a polymerizable styrene group via DCC coupling. Free-radical polymerization, followed by post-polymerization coordination to photogenerated W(CO)5 units yielded the title polymer, which showed thermal, spectroscopic, and electrochemical properties associated with each of the transition metals involved.
A Phosphine-Based Heterotrimetallic (M = Fe, Ru, W) Homo-Polymer, Amir Rabiee Kenaree, Joe Gilroy
A Phosphine-Based Heterotrimetallic (M = Fe, Ru, W) Homo-Polymer, Amir Rabiee Kenaree, Joe Gilroy
Chemistry Publications
An organometallic homopolymer containing three different metals per repeating unit was synthesized from an air- and moisture-stable secondary phosphine bearing ethylferrocene and ethylruthenocene groups. Hydrophosphination yielded a tertiary phosphine bearing an alcohol, which was then used to introduce a polymerizable styrene group via DCC coupling. Free-radical polymerization, followed by post-polymerization coordination to photogenerated W(CO)5 units yielded the title polymer, which showed thermal, spectroscopic, and electrochemical properties associated with each of the transition metals involved.
Dye Rejection Membranes Prepared From Oxidized Graphite Particles, Anastasia Colomba, Mark C. Biesinger, Ranjith Divigalpitiya, Frank A. Brandys, Joe Gilroy
Dye Rejection Membranes Prepared From Oxidized Graphite Particles, Anastasia Colomba, Mark C. Biesinger, Ranjith Divigalpitiya, Frank A. Brandys, Joe Gilroy
Chemistry Publications
This article reports the comparison of different chemical methods to produce graphite-based particles with varying degrees of oxidation as well as graphene oxide (GO) and pristine graphite (PG). Detailed physico-chemical characterization of the resulting materials was carried out, highlighting structural differences and variable oxygen content. The particles were then used to produce supported membranes, which were tested for the rejection of three different organic dyes (Rhodamine B, Methyl Blue and Congo Red), and their performance was rationalized in terms of a combination of properties of the membranes and dyes. In particular, membranes produced using edge-oxidized graphite (EOG) showed comparable performance …
Metal-Containing Polymers Bearing Pendant Nickel(Ii) Complexes Of Goedken's Macrocycle, Joseph A. Paquette, Amir Rabiee Kenaree, Joe Gilroy
Metal-Containing Polymers Bearing Pendant Nickel(Ii) Complexes Of Goedken's Macrocycle, Joseph A. Paquette, Amir Rabiee Kenaree, Joe Gilroy
Chemistry Publications
The design, synthesis, and polymerization of a norbornene-based monomer bearing a nickel(II) complex of Goedken's macrocycle (endo-13) and the characterization of the resulting polymer are described. Detailed studies of the ring-opening metathesis polymerization of endo-13 using the 3-bromopyridine adduct of Grubbs' 3rd generation catalyst revealed that the polymerization shares many characteristics associated with a living polymer, but deviated from ideal behavior when high degrees of polymerization were targeted. The installation of a 3-hexylphenyl substituent at the macrocyclic backbone allowed for the realization of soluble polymers (14) and shut down an oxidative dimerization pathway …
Poly(Ethyl Glyoxylate)-Poly(Ethylene Oxide) Nanoparticles: Stimuli- Responsive Drug Release Via End-To-End Polyglyoxylate Depolymerization, Bo Fan, Elizabeth Gillies
Poly(Ethyl Glyoxylate)-Poly(Ethylene Oxide) Nanoparticles: Stimuli- Responsive Drug Release Via End-To-End Polyglyoxylate Depolymerization, Bo Fan, Elizabeth Gillies
Chemistry Publications
The ability to disrupt polymer assemblies in response to specifi c stimuli provides the potential to release drugs selectively at certain sites or conditions in vivo. However, most stimuli-responsive delivery systems require many stimuli initiated events to release drugs. “ Self-immolative polymers” offer the potential to provide amplifi ed responses to stimuli as they undergo complete end-to-end depolymerization following the cleavage of a single end-cap. Herein, linker end-caps were developed to conjugate self-immolative poly(ethyl glyoxylate) (PEtG) with poly(ethylene oxide) (PEO) to form amphiphilic block copolymers. These copolymers were self-assembled to form nanoparticles in aqueous solution. Cleavage of the linker …
Phosphonium-Functionalized Polymer Micelles With Intrinsic Antibacterial Activity, Benjamin Hisey, Paul J. Ragogna, Elizabeth Gillies
Phosphonium-Functionalized Polymer Micelles With Intrinsic Antibacterial Activity, Benjamin Hisey, Paul J. Ragogna, Elizabeth Gillies
Chemistry Publications
New approaches to treat bacterial infections are badly needed to address the increasing problem of antibiotic resistance. This study explores phosphonium-functionalized block copolymer micelles as intrinsically antibacterial polymer assemblies. Phosphonium cations with varying alkyl lengths were conjugated to the terminus of a poly(ethylene oxide)− polycaprolactone block copolymer, and the phosphonium-functionalized block copolymers were self-assembled to form micelles in aqueous solution. The size, morphology, and ζ -potential of the assemblies were studied, and their abilities to kill Escherichia coli and Staphylococcus aureus were evaluated. It was found that the minimum bactericidal concentration depended on the phosphonium alkyl chain length, and different …
Deciphering Of Interactions Between Platinated Dna And Hmgb1 By Hydrogen/Deuterium Exchange Mass Spectrometry, Yuanyuan Wang, Zhifeng Du, Wei Zheng, Kui Wu, Decheng Xu, Qun Luo, Yao Zhao, Juanjuan Han, Yangzhong Liu, Fuyi Wang
Deciphering Of Interactions Between Platinated Dna And Hmgb1 By Hydrogen/Deuterium Exchange Mass Spectrometry, Yuanyuan Wang, Zhifeng Du, Wei Zheng, Kui Wu, Decheng Xu, Qun Luo, Yao Zhao, Juanjuan Han, Yangzhong Liu, Fuyi Wang
Chemistry Publications
A high mobility group box 1 (HMGB1) protein has been reported to recognize both 1,2-intrastrand crosslinked DNA by cisplatin (1,2-cis-Pt-DNA) and monofunctional platinated DNA using trans-[PtCl2(NH3)(thiazole)] (1-trans-PtTz-DNA). However, the molecular basis of recognition between the trans-PtTz-DNA and HMGB1 remains unclear. In the present work, we described a hydrogen/deuterium exchange mass spectrometry (HDX-MS) method in combination with docking simulation to decipher the interactions of platinated DNA with domain A of HMGB1. The global deuterium uptake results indicated that 1-trans-PtTz-DNA bound to HMGB1a slightly tighter than the 1,2-cis-Pt-DNA. The local deuterium uptake …
Synthesis, Properties, And Degradation Of Polyisobutylene-Polyester Graft Copolymers, Bethany A. Turowec, Elizabeth R. Gillies
Synthesis, Properties, And Degradation Of Polyisobutylene-Polyester Graft Copolymers, Bethany A. Turowec, Elizabeth R. Gillies
Chemistry Publications
The development of copolymers is a promising approach for combining the favorable properties of two polymers and obtaining new properties of the combination. In this work, graft copolymers of polyisobutylene (PIB) and polycaprolactone (PCL) or poly(D,L-lactide) (PDLLA) were synthesized and studied. Amine terminated polyesters were synthesized and were grafted onto an activated PIB backbone synthesized from butyl rubber, a copolymer of isobutylene and 2 mol % isoprene. The polyester content was tuned from 15 to 44 wt % by varying the molar mass of the polyester blocks and the number of molar equivalents used in the grafting reaction. The graft …
Highly Porous Photoluminescent Diazaborole-Linked Polymers: Synthesis, Characterization, And Application To Selective Gas Adsorption, Zafer Kahveci, Ali K. Sekizkardes, Ravi K. Arvapally, Logan Wilder, Hani M. El-Kaderi
Highly Porous Photoluminescent Diazaborole-Linked Polymers: Synthesis, Characterization, And Application To Selective Gas Adsorption, Zafer Kahveci, Ali K. Sekizkardes, Ravi K. Arvapally, Logan Wilder, Hani M. El-Kaderi
Chemistry Publications
The formation of boron–nitrogen (B–N) bonds has been widely explored for the synthesis of small molecules, oligomers, or linear polymers; however, its use in constructing porous organic frameworks remains very scarce. In this study, three highly porous diazaborole-linked polymers (DBLPs) have been synthesized by condensation reactions using 2,3,6,7,14,15-hexaaminotriptycene and aryl boronic acids. DBLPs are microporous and exhibit high Brunauer–Emmett–Teller surface area (730–986 m2 g−1) which enable their use in small gas storage and separation. At ambient pressure, the amorphous polymers show high CO2 (DBLP-4: 4.5 mmol g−1 at 273 K) and H2 (DBLP-3: 2.13 wt% at 77 K) uptake while …
Mesopore Etching Under Supercritical Conditions – A Shortcut To Hierarchically Porous Silica Monoliths, Martin Von Der Lehr, Kristof Hormann, Alexandra Höltzel, Lauren S. White, Arved E. Reising, Massimo F. Bertino, Bernd M. Smarsly, Ulrich Tallarek
Mesopore Etching Under Supercritical Conditions – A Shortcut To Hierarchically Porous Silica Monoliths, Martin Von Der Lehr, Kristof Hormann, Alexandra Höltzel, Lauren S. White, Arved E. Reising, Massimo F. Bertino, Bernd M. Smarsly, Ulrich Tallarek
Chemistry Publications
Hierarchically porous silica monoliths are obtained in the two-step Nakanishi process, where formation of a macro microporous silica gel is followed by widening micropores to mesopores through surface etching. The latter step is carried out through hydrothermal treatment of the gel in alkaline solution and necessitates a lengthy solvent exchange of the aqueous pore fluid before the ripened gel can be dried and calcined into a mechanically stable macro mesoporous monolith. We show that using an ethanol water (95.6/4.4, v/v) azeotrope as supercritical fluid for mesopore etching eliminates the solvent exchange, ripening, and drying steps of the classic route and …
Palladium Nanoparticles Supported On Ce-Metal–Organic Framework For Efficient Co Oxidation And Low-Temperature Co2 Capture, Andrew Lin, Amr Awad Ibrahim, Pezhman Arab, Hanii M. El-Kaderi, M. Samy El-Shall
Palladium Nanoparticles Supported On Ce-Metal–Organic Framework For Efficient Co Oxidation And Low-Temperature Co2 Capture, Andrew Lin, Amr Awad Ibrahim, Pezhman Arab, Hanii M. El-Kaderi, M. Samy El-Shall
Chemistry Publications
In this article, we report the lowest-temperature CO oxidation catalyst supported on metal–organic frameworks (MOFs). We have developed a facile, general, and effective approach based on microwave irradiation for the incorporation of Pd nanoparticle catalyst within Ce-MOF. The resulting Pd/Ce-MOF material is a unique catalyst that is capable of CO oxidation at modest temperatures and also of efficient uptake of the product CO2 gas at low temperatures. The observed catalytic activity of this material toward CO oxidation is significantly higher than those of other reported metal nanoparticles supported on MOFs. The high activity of the Pd/Ce-MOF catalyst is due to …
Roles Of Free Electrons And H2o2 In The Optical Breakdown-Induced Photochemical Reduction Of Aqueous [Aucl4]-, Victoria K. Meader, Mallory G. John, Collin Rodrigues, Katharine M. Tibbetts
Roles Of Free Electrons And H2o2 In The Optical Breakdown-Induced Photochemical Reduction Of Aqueous [Aucl4]-, Victoria K. Meader, Mallory G. John, Collin Rodrigues, Katharine M. Tibbetts
Chemistry Publications
Free electrons and H2O2 formed in an optical breakdown plasma are found to directly control the kinetics of [AuCl4]− reduction to form Au nanoparticles (AuNPs) during femtosecond laser-assisted synthesis of AuNPs. The formation rates of both free electrons and H2O2 strongly depend on the energy and duration of the 800 nm laser pulses over the ranges of 10−2400 μJ and 30−1500 fs. By monitoring the conversion of [AuCl4]− to AuNPs using in situ UV−vis spectroscopy during laser irradiation, the first- and second-order rate constants in the autocatalytic rate law, k1 and k2, were extracted and compared to the computed free …