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Full-Text Articles in Physical Sciences and Mathematics

Evaluating The Effect Of Resveratrol On Sirt1 With Different Peptide Substrates, Yujin Hur Jan 2023

Evaluating The Effect Of Resveratrol On Sirt1 With Different Peptide Substrates, Yujin Hur

Master's Theses

SIRT1 is an NAD+-dependent lysine deacetylase that is involved in many important cellular pathways. The protein has an extended N-terminal domain that seems to play a role in regulating its activity. Sirtuin Activating Compounds (STACs) are allosteric activators, such as resveratrol, that regulate the activity of SIRT1. STACs bind to the N-terminal STAC Binding Domain (SBD) in SIRT1. Past literature has found that SIRT1 activity can be increased, decreased, or remain unchanged by resveratrol depending on the identity of the peptide substrate. The goal of this study is to clarify the mechanism for substrate-specific allosteric regulation by resveratrol. The interactions …


Characterization And Evaluation Of Catalytic Activity Of Small Molecule Copper Complexes For Metallopolymer Design, Brenda Lu Jan 2023

Characterization And Evaluation Of Catalytic Activity Of Small Molecule Copper Complexes For Metallopolymer Design, Brenda Lu

Master's Theses

Catalysis is one of the driving forces in designing greener chemical processes for essential real-world applications. Enzymes, Nature’s catalysts, are known for their high selectivity, use of readily available metals and reagents, and ability to work under physiological conditions; three important qualities that synthetic chemists would like to mimic in their small molecule metal catalysts. Though most small molecule metal catalysts fall short of enzyme-like activity, we hypothesize that using a polymer scaffold as a secondary coordination sphere mimic around the metal complex will affect the microenvironment (steric and electronic) and enable enzyme-like activity. Previously, we synthesized ligand precursors and …


Optimizing Soluble Recombinant Expression Of The Aedes Aegypti Early Trypsin Protease, Neomi Millan Jan 2023

Optimizing Soluble Recombinant Expression Of The Aedes Aegypti Early Trypsin Protease, Neomi Millan

Master's Theses

The female Aedes aegypti mosquito is a primary vector for the transmission of blood–borne viral pathogens such as Chikungunya, Zika, Yellow Fever, and Dengue. The female mosquito will become infected with these pathogens through the uptake of a blood meal from an infected host. The midgut digestive enzymes are required to digest the blood meal to obtain necessary nutrients needed for the completion of the gonotrophic cycle. Blood meal digestion is biphasic and digestive enzymes are expressed at different time points after uptake of a blood meal. The focus of this study is on an early phase protease known as …


Single Chain Nanoparticles As Synthetic Enzyme Mimics, Tony Mo Jan 2023

Single Chain Nanoparticles As Synthetic Enzyme Mimics, Tony Mo

Master's Theses

Enzymes, nature’s catalysts, are a crucial component in biological reactions because they help lower the activation energy and speed up these reactions. They display impressive selectivity, catalytic activity, and specificity. However, they can be difficult to produce synthetically, especially on a large scale, and they are not suitable for all reactions for which synthetic catalysts are needed. Metalloenzymes contain a transition metal active site inside the primary coordination sphere (PCS) (ligands directly bound to the metal) that is surrounded by a secondary coordination sphere (SCS) (made up of more distant amino acids) which provides steric bulk and intramolecular interactions between …


Prediction And Confirmation Of A Switch-Like Region Within The N-Terminal Domain Of Hsirt1, Angelina T. Huynh, Thi-Tina N. Nguyen, Carina A. Villegas, Saira Montemorso, Benjamin Strauss, Richard A. Pearson, Jason G. Graham, Jonathan Oribello, Rohit Suresh, Brooke Lustig, Ningkun Wang May 2022

Prediction And Confirmation Of A Switch-Like Region Within The N-Terminal Domain Of Hsirt1, Angelina T. Huynh, Thi-Tina N. Nguyen, Carina A. Villegas, Saira Montemorso, Benjamin Strauss, Richard A. Pearson, Jason G. Graham, Jonathan Oribello, Rohit Suresh, Brooke Lustig, Ningkun Wang

Faculty Research, Scholarly, and Creative Activity

Many proteins display conformational changes resulting from allosteric regulation. Often only a few residues are crucial in conveying these structural and functional allosteric changes. These regions that undergo a significant change in structure upon receiving an input signal, such as molecular recognition, are defined as switch- like regions. Identifying these key residues within switch-like regions can help elucidate the mechanism of allosteric regulation and provide guidance for synthetic regulation. In this study, we combine a novel computational workflow with biochemical methods to identify a switch-like region in the N-terminal domain of human SIRT1 (hSIRT1), a lysine deacetylase that plays important …


Statistical Potentials For Rna-Protein Interactions Optimized By Cma-Es, Takayuki Kimura, Nobuaki Yasuo, Masakazu Sekijima, Brooke Lustig Oct 2021

Statistical Potentials For Rna-Protein Interactions Optimized By Cma-Es, Takayuki Kimura, Nobuaki Yasuo, Masakazu Sekijima, Brooke Lustig

Faculty Research, Scholarly, and Creative Activity

Characterizing RNA-protein interactions remains an important endeavor, complicated by the difficulty in obtaining the relevant structures. Evaluating model structures via statistical potentials is in principle straight-forward and effective. However, given the relatively small size of the existing learning set of RNA-protein complexes optimization of such potentials continues to be problematic. Notably, interaction-based statistical potentials have problems in addressing large RNA-protein complexes. In this study, we adopted a novel strategy with covariance matrix adaptation (CMA-ES) to calculate statistical potentials, successfully identifying native docking poses.


Ru(Ii)-Diimine Complexes And Cytochrome P450 Working Hand-In-Hand, Celine Eidenschenk, Lionel Cheruzel Sep 2020

Ru(Ii)-Diimine Complexes And Cytochrome P450 Working Hand-In-Hand, Celine Eidenschenk, Lionel Cheruzel

Faculty Publications, Chemistry

With a growing interest in utilizing visible light to drive biocatalytic processes, several light-harvesting units and approaches have been employed to harness the synthetic potential of heme monooxygenases and carry out selective oxyfunctionalization of a wide range of substrates. While the fields of cytochrome P450 and Ru(II) photochemistry have separately been prolific, it is not until the turn of the 21st century that they converged. Non-covalent and subsequently covalently attached Ru(II) complexes were used to promote rapid intramolecular electron transfer in bacterial P450 enzymes. Photocatalytic activity with Ru(II)-modified P450 enzymes was achieved under reductive conditions with a judicious choice of …


The Ability Of Vitreous Metabolite Concentration To Determine Time Of Death, Victoria Wiggins May 2020

The Ability Of Vitreous Metabolite Concentration To Determine Time Of Death, Victoria Wiggins

Themis: Research Journal of Justice Studies and Forensic Science

This paper analyzes the ability of vitreous fluid to determine time of death. The high variability in current methods used to establish post-mortem interval (PMI), or the amount of time between death and post-mortem examination make it difficult to obtain an accurate estimation. The concentration of metabolites found within vitreous fluid, such as potassium (K+), hypoxanthine (Hx), and magnesium (Mg), are the most researched alternatives to traditional methods in PMI determination because of the relative isolation of vitreous within the body and its ability to withstand degradation. There is no clear consensus on which metabolite provides the most accurate data …


The Development Of Silica Hydride Stationary Phases For High-Performance Liquid Chromatography From Conception To Commercialization, Maria Matyska-Pesek, Joseph Pesek May 2019

The Development Of Silica Hydride Stationary Phases For High-Performance Liquid Chromatography From Conception To Commercialization, Maria Matyska-Pesek, Joseph Pesek

Faculty Publications, Chemistry

The development of a stationary phase material for high-performance liquid chromatography based on a surface of silica hydride as opposed to silanols on ordinary silica is discussed including synthetic approaches, characterization, and applications. There are several synthetic approaches available to create a silica hydride surface. Modification of the Si–H moiety on the silica surface can be accomplished through the use of a hydrosilation reaction. Both the intermediate silica hydride and the material modified with an organic moiety can be characterized by a number of spectroscopic as well as a variety of other methods. Further insights into the retention mechanism are …


The Importance Of Solvent Effects On The Mechanism Of The Pfeiffer Effect, Jamie Lunkley, Ngoc Nguyen, Kristina Tuminaro, Dana Margittai, Gilles Muller Aug 2018

The Importance Of Solvent Effects On The Mechanism Of The Pfeiffer Effect, Jamie Lunkley, Ngoc Nguyen, Kristina Tuminaro, Dana Margittai, Gilles Muller

Faculty Publications, Chemistry

The Pfeiffer effect is observed when an optically active compound such as an amino acid is introduced to a solution containing a labile racemic metal complex, and an equilibrium shift is obtained. The “perturbation” results in an excess of one enantiomer over the other. The shift is a result of a preferential outer sphere interaction between the introduced chiral species and one enantiomeric form (Λ or ∆) of a labile metal complex. Speculations regarding the mechanism of the Pfeiffer effect have attributed observations to a singular factor such as pH, solvent polarity, or numerous other intermolecular interactions. Through the use …


Superconductivity At Т≈200 K In Bismuth Cuprates Synthesized Using Solar Energy, J. Chigvinadze, Juana Acrivos, S. Ashimov, D. Gulamova, G. Donadze Oct 2017

Superconductivity At Т≈200 K In Bismuth Cuprates Synthesized Using Solar Energy, J. Chigvinadze, Juana Acrivos, S. Ashimov, D. Gulamova, G. Donadze

Faculty Publications, Chemistry

When investigating low-frequency (0.1 Hz) oscillations of multiphase high-temperature cuprate superconductors (HTCS) Bi1,7Pb0,3Sr2Ca(n-1)CunOy (n=2-30), a wide attenuation peak (ΔT~100 К) with a maximum at Т≈200 К was detected. This peak was particularly pronounced in field cooling (FC) experiments, i.e. after abrupt cooling of the sample in the external magnetic field at the temperature Т<Тс with subsequent slow warming up to room temperature with invariance of the applied field. The attenuation peak height depended on the preliminaryorientation (before cooling) of the samples θ in the measured permanent magnetic field Н. On the one hand, it is well known that, after the FC procedure and subsequent slow warming up, at the temperatures close to the critical temperature Тс, the attenuation peak associated with “melting” of the Abrikosov frozen vortex structure and its disappearance at Т >Тс is detected in monophase samples. At the same time, in most multiphase bismuth HTCS samples, synthesized using solar energy and superfast quenching of the melt, the attenuation peak with the maximum at Т≈200 К was observed.Depending on the conditions of synthesis, the attenuation peak could …


Spin-Imbalance In A 2d Fermi-Hubbard System, Peter Brown, Debayan Mitra, Elmer Guardado-Sanchez, Peter Schauß, Stanimir Kondov, Ehsan Khatami, Thereza Paiva, Nandini Trivedi, David Huse, Waseem Bakr Sep 2017

Spin-Imbalance In A 2d Fermi-Hubbard System, Peter Brown, Debayan Mitra, Elmer Guardado-Sanchez, Peter Schauß, Stanimir Kondov, Ehsan Khatami, Thereza Paiva, Nandini Trivedi, David Huse, Waseem Bakr

Faculty Publications

The interplay of strong interactions and magnetic fields gives rise to unusual forms of superconductivity and magnetism in quantum many-body systems. Here, we present an experimental study of the two-dimensional Fermi-Hubbard model—a paradigm for strongly correlated fermions on a lattice—in the presence of a Zeeman field and varying doping. Using site-resolved measurements, we revealed anisotropic antiferromagnetic correlations, a precursor to long-range canted order. We observed nonmonotonic behavior of the local polarization with doping for strong interactions, which we attribute to the evolution from an antiferromagnetic insulator to a metallic phase. Our results pave the way to experimentally mapping the low-temperature …


Abca' Tetrablock Terpolymers: Synthesis And Morphology, Madalyn Radlauer, Seijiro Fukuta, Megan Matta, Joshua Van Benschoten, Marc Hillmyer May 2017

Abca' Tetrablock Terpolymers: Synthesis And Morphology, Madalyn Radlauer, Seijiro Fukuta, Megan Matta, Joshua Van Benschoten, Marc Hillmyer

Faculty Publications, Chemistry

No abstract provided.


Proximal Effects In Bimetallic Catalysts For Olefin Polymerization, In Cross Metathesis Of Poly(3-R-Cyclooctenes), And In Multiblock Polymers, Madalyn Radlauer, Theodor Agapie, Marc Hillmyer Aug 2016

Proximal Effects In Bimetallic Catalysts For Olefin Polymerization, In Cross Metathesis Of Poly(3-R-Cyclooctenes), And In Multiblock Polymers, Madalyn Radlauer, Theodor Agapie, Marc Hillmyer

Faculty Publications, Chemistry

Proximity and sterics play a large role in polymerization and polymer chemistry. In the development and testing of bimetallic polymerization catalysts where the two metal centers are held on the same side of the molecule by a rigid ligand framework, the proximity of the second metal changes reactivity at the first. The resulting enhancements of polar group tolerance or isoselecitivity in olefin polymerization are not observed in related bimetallic systems with distal metal centers or in monometallic analogues. In cross metathesis between poly(cyclooctene) chains, high E-stereoregularity and head-to-tail regioregularity are achieved with Grubbs second or third generation catalysts when there …


Conformational Changes And Chiroptical Switching Of Enantiopure Bis-Helicenic Terpyridine Upon Zn2+ Binding, Helena Isla, Monika Srebro-Hooper, Marion Jean, Nicolas Vanthuyne, Thierry Roisnel, Jamie Lunkley, Gilles Muller, J. Gareth-Williams, Jochen Autschbach, Jeanne Crassous Jan 2016

Conformational Changes And Chiroptical Switching Of Enantiopure Bis-Helicenic Terpyridine Upon Zn2+ Binding, Helena Isla, Monika Srebro-Hooper, Marion Jean, Nicolas Vanthuyne, Thierry Roisnel, Jamie Lunkley, Gilles Muller, J. Gareth-Williams, Jochen Autschbach, Jeanne Crassous

Faculty Publications, Chemistry

The molecular conformation of a bis-helicenic terpyridine system is strongly modified upon binding to Zn(II) ion, a process that is accompanied by large changes in the optical and chiroptical properties. This system affords a new type of helicene-based chiroptical switching.


Functionalized Cationic [4]Helicenes With Unique Tuning Of Absorption, Fluorescence And Chiroptical Properties Up To The Far-Red Range, I. Hernández Delgado, S. Pascal, A. Wallabregue, R. Duwald, C. Besnard, L. Guénée, C. Nançoz, E. Vauthey, R. Tovar, J. Lunkley, Gilles Muller, J. Lacour Jan 2016

Functionalized Cationic [4]Helicenes With Unique Tuning Of Absorption, Fluorescence And Chiroptical Properties Up To The Far-Red Range, I. Hernández Delgado, S. Pascal, A. Wallabregue, R. Duwald, C. Besnard, L. Guénée, C. Nançoz, E. Vauthey, R. Tovar, J. Lunkley, Gilles Muller, J. Lacour

Faculty Publications, Chemistry

Unprecedented regioselective post-functionalization of racemic and enantiopure cationic diaza [4]helicenes is afforded. The peripheral auxochrome substituents allow a general tuning of the electrochemical, photophysical and chiroptical properties of the helical dyes (26 examples). For instance, electronic absorption and circular dichroism are modulated from the orange to near-infrared spectral range (575–750 nm), fluorescence quantum efficiency is enhanced up to 0.55 (631 nm) and circularly polarized luminescence is recorded in the red (|glum| ∼ 10−3).


Logistic Regression Models To Predict Solvent Accessible Residues Using Sequence- And Homology-Based Qualitative And Quantitative Descriptors Applied To A Domain-Complete X-Ray Structure Learning Set, Reecha Nepal, Joanna Spencer, Guneet Bhogal, Amulya Nedunuri, Thomas Poelman, Thejas Kamath, Edwin Chung, Katherine Kantardjieff, Andrea Gottlieb, Brooke Lustig Dec 2015

Logistic Regression Models To Predict Solvent Accessible Residues Using Sequence- And Homology-Based Qualitative And Quantitative Descriptors Applied To A Domain-Complete X-Ray Structure Learning Set, Reecha Nepal, Joanna Spencer, Guneet Bhogal, Amulya Nedunuri, Thomas Poelman, Thejas Kamath, Edwin Chung, Katherine Kantardjieff, Andrea Gottlieb, Brooke Lustig

Faculty Publications, Chemistry

A working example of relative solvent accessibility (RSA) prediction for proteins is presented. Novel logistic regression models with various qualitative descriptors that include amino acid type and quantitative descriptors that include 20- and six-term sequence entropy have been built and validated. A domain-complete learning set of over 1300 proteins is used to fit initial models with various sequence homology descriptors as well as query residue qualitative descriptors. Homology descriptors are derived from BLASTp sequence alignments, whereas the RSA values are determined directly from the crystal structure. The logistic regression models are fitted using dichotomous responses indicating buried or accessible solvent, …


Frustrated Abc Triblock Terpolymers Morphologies, Madalyn Radlauer, Yusuke Asai, Christophe Sinturel, Marc Hillmyer Jun 2015

Frustrated Abc Triblock Terpolymers Morphologies, Madalyn Radlauer, Yusuke Asai, Christophe Sinturel, Marc Hillmyer

Faculty Publications, Chemistry

No abstract provided.


Potential Switchable Circularly Polarized Luminescence From Chiral Cyclometalated Platinum(Ii) Complexes, Xiao-Peng Zhang Zhang, Victoria Chang, Jian Liu, Xiao-Liang Yang, Wei Huan, Yizhi Li, Cheng-Hui Li, Gilles Muller, Xiao-Zeng You Jan 2015

Potential Switchable Circularly Polarized Luminescence From Chiral Cyclometalated Platinum(Ii) Complexes, Xiao-Peng Zhang Zhang, Victoria Chang, Jian Liu, Xiao-Liang Yang, Wei Huan, Yizhi Li, Cheng-Hui Li, Gilles Muller, Xiao-Zeng You

Faculty Publications, Chemistry

A series of chiral cyclometalated platinum(II) complexes, [Pt((−)-L1)(Dmpi)]Cl ((−)-1), [Pt((+)-L1)(Dmpi)]Cl ((+)-1), [Pt((−)-L2)(Dmpi)]Cl ((−)-2), [Pt((+)-L2)(Dmpi)]Cl ((+)-2), [Pt3((−)-L2)2(Dmpi)4](ClO4)4 ((−)-3), and [Pt3((+)-L2)2(Dmpi)4](ClO4)4 ((+)-3) [(−)-L1 = (−)-4,5-pinene-6′-phenyl-2,2′-bipyridine, (+)-L1 = (+)-4,5-pinene-6′-phenyl-2,2′-bipyridine), (−)-L2 = (−)-1,3-bis(2-(4,5-pinene)pyridyl)benzene, (+)-L2 = (+)-1,3-bis(2-(4,5-pinene)pyridyl)benzene, Dmpi = 2,6-dimethylphenyl isocyanide], have been designed and synthesized. In aqueous solutions, (−)-1 and (+)-1 aggregate into one-dimensional helical chain structures through Pt···Pt, π–π, and hydrophobic–hydrophobic interactions. (−)-3 and (+)-3 represent a novel helical structure with Pt–Pt bonds. The formation of helical structures results in enhanced and distinct chiroptical properties as evidenced by circular dichroism spectra. Circularly polarized luminescence (CPL) was observed from the aggregates of (−)-1 and …


Enantio-Enriched Cpl-Active Helicene–Bipyridine–Rhenium Complexes, Nidal Saleh, Monika Srebro, Thibault Reynaldo, Nicolas Vanthuyne, Loïc Toupet, Victoria Chang, Gilles Muller, J. Gareth-Williams, Christian Roussel, Jochen Autschbach, Jeanne Crassous Jan 2015

Enantio-Enriched Cpl-Active Helicene–Bipyridine–Rhenium Complexes, Nidal Saleh, Monika Srebro, Thibault Reynaldo, Nicolas Vanthuyne, Loïc Toupet, Victoria Chang, Gilles Muller, J. Gareth-Williams, Christian Roussel, Jochen Autschbach, Jeanne Crassous

Faculty Publications, Chemistry

The incorporation of a rhenium atom within an extended helical π-conjugated bi-pyridine system impacts the chiroptical and photophysical properties of the resulting neutral or cationic complexes, leading to the first examples of rhenium-based phosphors that exhibit circularly polarized luminescence.


Fast Melt Cooled Superconducting Alloys: (Bi1.97pb0.03sr2can‐1cuno2n+4+Δ)2 N/N’ N<24 Intergrowth, J. Kmiec, Juana Acrivos, D. Gulamova, J. Chigvinadze Oct 2012

Fast Melt Cooled Superconducting Alloys: (Bi1.97pb0.03sr2can‐1cuno2n+4+Δ)2 N/N’ N<24 Intergrowth, J. Kmiec, Juana Acrivos, D. Gulamova, J. Chigvinadze

Faculty Publications, Chemistry

High temperature layer superconducting cuprate (HTLSC) alloys: (Bi1.97Pb0.03Sr2Can-1CunO2n+4+δ)2 called (2s:2:n-1:n) have been grown from n-oxide stoichiometric melts in concentrated sun flux, followed by rapid cooling SFQA technology that preserves the melt tiling after annealing at 845±5oC**. Synchrotron XRD at the DOE SLAC-SSRL near the Cu K-edge has identified the mixing of n ≠ n’ alloys as observed by many in thin films last century. An ideal D17 4h Space Group structure obtains {an, bn, cn} = {3.815 Å, an+ubn, 2dP(n+3)+ucn} where dP is a perovskite sandwich, (CuO2)1/2|_Ca|(CuO2)1/2, thickness, and un are the amplitudes of periodic lattice distortions, PLD also observed …


Résonance Dans Alliages Des Couches Supraconductrices Refroidi Rapidement: (Bi1.7pb0.3sr2can‐1cuno2n+4+Δ)2, N=1 To 9détecté Par Local Renforcée Atomique Xrd, Juana Acrivos, J. Chigvinadze, D. Gulamova May 2012

Résonance Dans Alliages Des Couches Supraconductrices Refroidi Rapidement: (Bi1.7pb0.3sr2can‐1cuno2n+4+Δ)2, N=1 To 9détecté Par Local Renforcée Atomique Xrd, Juana Acrivos, J. Chigvinadze, D. Gulamova

Faculty Publications, Chemistry

Lien résonance dans alliages supraconductrice à haute température (HTLSC): (Bi1.7Pb0.3Sr2Can-1CunO2n+4+δ)2,n=1-9 appelé (2s:2:n-1:n) préparé en Ouzbékistan à partir de oxide fondu par flux concentré du Soleil, suivi d'un refroidissement rapide, technologie SFQA préserve fondre carrelage. Tc,n est mesurée en Tbilissi, et atomique local renforcée synchrotron diffraction des rayons X, (XRD) à proximité de la Cu-K bord est effectuée à DOE National Laboratoire SLAC-SSRL. La structure indexé dans le groupe D17 4h démontre qui (n-1) unîtes: (CuO2)1/2/Ca/(CuO2)1/2 sont intercalés à chaque extrémité de la phase n=1: [(CuO2)1/2/SrO/Bi1.7Pb0.3O/Bi1.7Pb0.3O/SrO/(CuO2)1/2]2. Les effets de surface conduit à intercalations des different n-phase, et à des distorsions réseau …


Covalent Bonds In Superconducting Rapid Cooled Alloys: (Bi1.7pb0.3sr2can‐1cuno2n+4+Δ)2, N=1 To 9 Detected By Local Atomic Enhanced Xrd, J. Kmiec, K. Tyson, Juana Acrivos, D. Gulamova, J. Chigvinadze Apr 2012

Covalent Bonds In Superconducting Rapid Cooled Alloys: (Bi1.7pb0.3sr2can‐1cuno2n+4+Δ)2, N=1 To 9 Detected By Local Atomic Enhanced Xrd, J. Kmiec, K. Tyson, Juana Acrivos, D. Gulamova, J. Chigvinadze

Faculty Publications, Chemistry

High temperature layer superconducting cuprates (HTLSC) alloys: (Bi1.7Pb0.3Sr2Can-1CunO2n+4+δ)2,n=1-9 called (2s:2:n-1:n) prepared in Uzbekistan from melts in concentrated sun flux, followed by rapid cooling, SFQA technology that preserves melt tiling by confinement of conduction layer: |(CuO2)1/2|Ca|(CuO2)1/2]n-1| in the hard shell ||, of the n=1 phase,[(CuO2)1/2|SrO|Bi1.7Pb0.3O|Bi1.7Pb0.3O|SrO|(CuO2)1/2]2. Disproportion leads to different n-phase mixing, and periodic lattice distortions (PLD) through bond resonance covalent crystalaxes: 2(rCu+2+rO-2)=4.2Å>a=3.82Å>d(CuO)+2-3/2d(O3))=3.2Å≈(cn-c1)/2(n-1). Individual phase local bonds Cu-Ca, Cu-Sr, Cu-O-Cu are ascertained by X-Ray diffraction near Cu K-edgefollowed by Cu-Ca bond scattering. The HTLSC density, ρ decrease as n increases obtains Tc,n ~180 K, identified due to n=8 phase on …


Bond Resonance In Superconducting Rapid Cooled Alloys: (Bi1.7pb0.3sr2can‐1cuno2n+4+Δ)2, N=1 To 9 Detected By Novel Local Atomic Enhanced Xrd, K Tyson, J Kmiec, Juana Acrivos, D. Gulamova, J Chigvinadze Mar 2012

Bond Resonance In Superconducting Rapid Cooled Alloys: (Bi1.7pb0.3sr2can‐1cuno2n+4+Δ)2, N=1 To 9 Detected By Novel Local Atomic Enhanced Xrd, K Tyson, J Kmiec, Juana Acrivos, D. Gulamova, J Chigvinadze

Faculty Publications, Chemistry

We discuss bond resonance in high temperature layer superconducting cuprates, HTLSC alloys: (Bi1.7Pb0.3Sr2Can‐1CunO2n+4+δ)2,n=1‐9 called (2s:2:n‐1:n) prepared in Uzbekistan from melts in concentrated sun flux, followed by rapid cooling, SFQA technology that preserves melt tiling, Tc,n measured in Tiblisi, and local atomic enhanced synchrotron X‐ray diffraction, XRD near the Cu K‐edge at DOE National Laboratory SLAC‐SSRL. The SFQA alloys structure indexed in the ideal D17 4h Space Group indicates (n‐1) units: (CuO2)1/2/Ca/(CuO2)1/2 are intercalated at each end of the n=1 phase [(CuO2)1/2/SrO/Bi1.7Pb0.3O/Bi1.7Pb0.3O/SrO/(CuO2)1/2]2. Surface effects lead to different n‐phase mixing, and periodic lattice distortions, PLD, through bond resonance in crystal axes: 2(rCu+2+rO‐2)=4.2Å …


Silica As A Matrix For Encapsulating Proteins:Surface Effects On Protein Structure Assessed By Circular Dichroism Spectroscopy, Daryl K. Eggers, P. J. Calabretta, M. C. Chancellor, C. Torres, G. R. Abel Jr., C. Neihaus, N. J. Birtwhistle, N. M. Khouderchah, G. H. Zemede Jan 2012

Silica As A Matrix For Encapsulating Proteins:Surface Effects On Protein Structure Assessed By Circular Dichroism Spectroscopy, Daryl K. Eggers, P. J. Calabretta, M. C. Chancellor, C. Torres, G. R. Abel Jr., C. Neihaus, N. J. Birtwhistle, N. M. Khouderchah, G. H. Zemede

Faculty Publications, Chemistry

The encapsulation of biomolecules in solid materials that retain the native properties of the molecule is a desired feature for the development of biosensors and biocatalysts. In the current study, protein entrapment in silica-based materials is explored using the sol-gel technique. This work surveys the effects of silica confinement on the structure of several model polypeptides, including apomyoglobin, copper-zinc superoxide dismutase, polyglutamine, polylysine, and type I antifreeze protein. Changes in the secondary structure of each protein following encapsulation are monitored by circular dichroism spectroscopy. In many cases, silica confinement reduces the fraction of properly-folded protein relative to solution, but addition …


Silica As A Matrix For Encapsulating Proteins:Surface Effects On Protein Structure Assessed By Circular Dichroism Spectroscopy, Daryl K. Eggers, P. J. Calabretta, M. C. Chancellor, C. Torres, G. R. Abel Jr., C. Neihaus, N. J. Birtwhistle, N. M. Khouderchah, G. H. Zemede Jan 2012

Silica As A Matrix For Encapsulating Proteins:Surface Effects On Protein Structure Assessed By Circular Dichroism Spectroscopy, Daryl K. Eggers, P. J. Calabretta, M. C. Chancellor, C. Torres, G. R. Abel Jr., C. Neihaus, N. J. Birtwhistle, N. M. Khouderchah, G. H. Zemede

Daryl K. Eggers

The encapsulation of biomolecules in solid materials that retain the native properties of the molecule is a desired feature for the development of biosensors and biocatalysts. In the current study, protein entrapment in silica-based materials is explored using the sol-gel technique. This work surveys the effects of silica confinement on the structure of several model polypeptides, including apomyoglobin, copper-zinc superoxide dismutase, polyglutamine, polylysine, and type I antifreeze protein. Changes in the secondary structure of each protein following encapsulation are monitored by circular dichroism spectroscopy. In many cases, silica confinement reduces the fraction of properly-folded protein relative to solution, but addition …


Chemical Activity In Yba2cu3o7 − Δ Across The Normal To Superconducting Phase Transition, Juana Vivó Acrivos Nov 2011

Chemical Activity In Yba2cu3o7 − Δ Across The Normal To Superconducting Phase Transition, Juana Vivó Acrivos

Faculty Publications, Chemistry

The Gibbs free enthalpy, chemical activity across the transition temperature to superconductivity, Tc in YBa2Cu3O7 − δ is obtained from reciprocally enhanced X-Ray absorbance, XAS and diffraction, XRD data near the Ba L3,2 edges' energy Ea, and orientations in the X-ray beam for preferred Miller indexed [HKL] planes' scattering, that are enhanced near Tc. The standard enthalpy and entropy for the formation of mixed normal metal/superconducting domains above Tc, determined individually across the two Ba L3,2 edges, to better than a percent accuracy: ΔH≠≥ = − 220 meV, and ΔS≠≥ = − 2 meV/K when 121 ≥ T ≥ 92 …


Chemical Activity In Yba2cu3o7 − Δ Across The Normal To Superconducting Phase Transition, Juana Vivó Acrivos Nov 2011

Chemical Activity In Yba2cu3o7 − Δ Across The Normal To Superconducting Phase Transition, Juana Vivó Acrivos

Juana Vivó Acrivos

The Gibbs free enthalpy, chemical activity across the transition temperature to superconductivity, Tc in YBa2Cu3O7 − δ is obtained from reciprocally enhanced X-Ray absorbance, XAS and diffraction, XRD data near the Ba L3,2 edges' energy Ea, and orientations in the X-ray beam for preferred Miller indexed [HKL] planes' scattering, that are enhanced near Tc. The standard enthalpy and entropy for the formation of mixed normal metal/superconducting domains above Tc, determined individually across the two Ba L3,2 edges, to better than a percent accuracy: ΔH≠≥ = − 220 meV, and ΔS≠≥ = − 2 meV/K when 121 ≥ T ≥ 92 …


University Scholar Series: Marc D'Alarcao, Marc D'Alarcao Mar 2011

University Scholar Series: Marc D'Alarcao, Marc D'Alarcao

University Scholar Series

Synthetic Organic Chemistry to Shed Light on Type II Diabetes and Cancer

On March 16, 2011 Marc d'Alarcao spoke in the University Scholar Series hosted by Provost Gerry Selter at the Dr. Martin Luther King, Jr. Library. Marc d'Alarcao is a Professor in the Chemistry Department at SJSU. In this seminar, he gives a progress report on his work aimed at developing and synthesizing new compounds that are designed to take advantage of this metabolic difference. His hope is that these compounds will be selectively toxic to cancer cells and may provide a new strategy for treating this major threat …


A Bulk Water-Dependent Desolvation Energy Model For Analyzing The Effects Of Secondary Solutes On Biological Equilibria, Daryl K. Eggers Jan 2011

A Bulk Water-Dependent Desolvation Energy Model For Analyzing The Effects Of Secondary Solutes On Biological Equilibria, Daryl K. Eggers

Faculty Publications, Chemistry

A new phenomenological model for interpreting the effects of solutes on biological equilibria is presented. The model attributes changes in equilibria to differences in the desolvation energy of the reacting species that, in turn, reflect changes in the free energy of the bulk water upon addition of secondary solutes. The desolvation approach differs notably from that of other solute models by treating the free energy of bulk water as a variable and by not ascribing the observed shifts in reaction equilibria to accumulation or depletion of solutes next to the surfaces of the reacting species. On the contrary, the partitioning …