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Medicinal-Pharmaceutical Chemistry Commons

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University of Nebraska - Lincoln

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Full-Text Articles in Medicinal-Pharmaceutical Chemistry

Analysis Of Drug-Protein Interactions During Diabetes By High-Performance Affinity Chromatography, Pingyang Tao Apr 2019

Analysis Of Drug-Protein Interactions During Diabetes By High-Performance Affinity Chromatography, Pingyang Tao

Student Research Projects, Dissertations, and Theses - Chemistry Department

High-performance affinity chromatography (HPAC) is a type of liquid chromatography in which solutes are separated based on their binding to a stationary phase that is a biologically-related agent. Sulfonylurea drugs have significant binding to proteins in blood, with most of this binding is believed to occur with human serum albumin (HSA). HSA is known to be modified as a result of the high serum levels of glucose that is present during diabetes, which may also alter the function of HSA as a binding agent for many drugs in circulation. Some modifications of HSA that can occur during diabetes involves early ...


Urease Is An Essential Component Of The Acid Response Network Of Staphylococcus Aureus And Is Required For A Persistent Murine Kidney Infection, Chunyi Zhou, Fatema Bhinderwala, Mckenzie K. Lehman, Vinai C. Thomas, Sujata S. Chaudhari, Kelsey J. Yamada, Kirk W. Foster, Robert Powers, Tammy Kielian, Paul D. Fey Jan 2019

Urease Is An Essential Component Of The Acid Response Network Of Staphylococcus Aureus And Is Required For A Persistent Murine Kidney Infection, Chunyi Zhou, Fatema Bhinderwala, Mckenzie K. Lehman, Vinai C. Thomas, Sujata S. Chaudhari, Kelsey J. Yamada, Kirk W. Foster, Robert Powers, Tammy Kielian, Paul D. Fey

Faculty Publications -- Chemistry Department

Staphylococcus aureus causes acute and chronic infections resulting in significant morbidity. Urease, an enzyme that generates NH3 and CO2 from urea, is key to pH homeostasis in bacterial pathogens under acidic stress and nitrogen limitation. However, the function of urease in S. aureus niche colonization and nitrogen metabolism has not been extensively studied. We discovered that urease is essential for pH homeostasis and viability in urea-rich environments under weak acid stress. The regulation of urease transcription by CcpA, Agr, and CodY was identified in this study, implying a complex network that controls urease expression in response to changes ...


Role Of Water On The Rotational Dynamics Of The Organic Methylammonium Cation: A First Principles Analysis, Ross D. Hoehn, Joseph S. Francisco, Sabre Kais, Ali Kachmar Jan 2019

Role Of Water On The Rotational Dynamics Of The Organic Methylammonium Cation: A First Principles Analysis, Ross D. Hoehn, Joseph S. Francisco, Sabre Kais, Ali Kachmar

Faculty Publications -- Chemistry Department

Understanding the degradation mechanisms of lead-halide perovskites (CH3NH3PbI3) under exposure to liquid/aerosol water is an essential problem within the photovoltaic community. Herein we investigate both the static and the dynamic properties of the methylammonuim cation (MA) as it coordinates with invading water molecules (MA.(H2O)n, n = 1, 2, 3, 4) using both stationary state quantum mechanics and first principle molecular dynamics simulations. Various solvation structures of MA were characterized by their stabilization energies, dipoles, and Maximally-Localized Wannier Function (MLWF) centers. Calculation – and analysis – of vibrational shifts in the IR spectral region ...


Highly Stable And Efficient All-Inorganic Lead-Free Perovskite Solar Cells With Native-Oxide Passivation, Min Chen, Ming-Gang Ju, Hector F. Garces, Alexander D. Carl, Luis K. Ono, Zafer Hawash, Yi Zhang, Tianyi Shen, Yabing Qi, Ronald L. Grimm, Domenico Pacifici, Xiao Cheng Zeng, Yuanyuan Zhou, Nitin P. Padture Jan 2019

Highly Stable And Efficient All-Inorganic Lead-Free Perovskite Solar Cells With Native-Oxide Passivation, Min Chen, Ming-Gang Ju, Hector F. Garces, Alexander D. Carl, Luis K. Ono, Zafer Hawash, Yi Zhang, Tianyi Shen, Yabing Qi, Ronald L. Grimm, Domenico Pacifici, Xiao Cheng Zeng, Yuanyuan Zhou, Nitin P. Padture

Faculty Publications -- Chemistry Department

There has been an urgent need to eliminate toxic lead from the prevailing halide perovskite solar cells (PSCs), but the current lead-free PSCs are still plagued with the critical issues of low efficiency and poor stability. This is primarily due to their inadequate photovoltaic properties and chemical stability. Herein we demonstrate the use of the lead-free, allinorganic cesium tin-germanium triiodide (CsSn0.5Ge0.5I3) solid-solution perovskite as the light absorber in PSCs, delivering promising efficiency of up to 7.11%. More importantly, these PSCs show very high stability, with less than 10% decay in efficiency after ...


The Inductive Effect In Organic Chemistry, Charles A. Kingsbury Jan 2019

The Inductive Effect In Organic Chemistry, Charles A. Kingsbury

Faculty Publications -- Chemistry Department

The subtle difference between the successive polarization model and the flow of electrons through sigma bonds is explored, as well as the alternating charge model of Pople and the pervasive field model. The present paper is concerned with the ability of alkyl groups to serve as sigma inductive electron donors.


Mass Spectrometry And Nuclear Magnetic Resonance In The Chemometric Analysis Of Cellular Metabolism, Eli Riekeberg Nov 2018

Mass Spectrometry And Nuclear Magnetic Resonance In The Chemometric Analysis Of Cellular Metabolism, Eli Riekeberg

Student Research Projects, Dissertations, and Theses - Chemistry Department

The development and awareness of Machine Learning and “big data” has led to a growing interest in applying these methods to bioanalytical research. Methods such as Mass Spectrometry (MS), and Nuclear Magnetic Resonance (NMR) can now obtain tens of thousands to millions of data points from a single sample, due to fundamental instrumental advances and ever-increasing resolution. Simple pairwise comparisons on datasets of this magnitude can obfuscate more complex underlying trends, and does a disservice to the richness of information contained within. This necessitates the need for multivariate approaches that can more fully take advantage of the complexity of these ...


‘Cassette’-Ises (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds For Hydrolytic Kinetic Resolution Across A Range Of Epoxides, Sangeeta Dey, Douglas R. Powell, Chunhua Hu, David B. Berkowitz Oct 2018

‘Cassette’-Ises (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds For Hydrolytic Kinetic Resolution Across A Range Of Epoxides, Sangeeta Dey, Douglas R. Powell, Chunhua Hu, David B. Berkowitz

Faculty Publications -- Chemistry Department

‘Cassette’-ISES (In Situ Enzymatic Screening) Identifies Complementary Chiral Scaffolds for Hydrolytic Kinetic Resolution Across a Range of Epoxides

A new ‘Cassette’-In Situ Enzymatic Screen (ISES) for combinatorial catalysis is introduced. This allows the experimentalist to obtain an information-rich readout, in real time, providing an estimate of the sense and magnitude of enantioselectivity across more than one substrate. In its first iteration, the screen identified CoIII-salen catalysts with β-pinene- and α-naphthylalanine-derived chiral scaffolds with broad, yet complementary, substrate specificities.


A High Throughput Approach For The Generation Of Orthogonally Interacting Protein Pairs, Justin Lawrie, Xi Song, Wei Niu, Jiantao Guo Jan 2018

A High Throughput Approach For The Generation Of Orthogonally Interacting Protein Pairs, Justin Lawrie, Xi Song, Wei Niu, Jiantao Guo

Faculty Publications -- Chemistry Department

In contrast to the nearly error-free self-assembly of protein architectures in nature, artificial assembly of protein complexes with pre-defined structure and function in vitro is still challenging. To mimic nature’s strategy to construct pre-defined three-dimensional protein architectures, highly specific proteinprotein interacting pairs are needed. Here we report an effort to create an orthogonally interacting protein pair from its parental pair using a bacteria-based in vivo directed evolution strategy. This high throughput approach features a combination of a negative and a positive selection. The newly developed negative selection from this work was used to remove any protein mutants that retain ...


Toward The Detection Of The Triatomic Negative Ion Spn−: Spectroscopy And Potential Energy Surfaces, Tarek Trabelsi, Majdi Hochlaf, Joseph S. Francisco Jan 2018

Toward The Detection Of The Triatomic Negative Ion Spn−: Spectroscopy And Potential Energy Surfaces, Tarek Trabelsi, Majdi Hochlaf, Joseph S. Francisco

Faculty Publications -- Chemistry Department

High level theoretical calculations using coupled-cluster theory were performed to provide an accurate description of the electronic structure, spectroscopic properties, and stability of the triatomic negative ion comprising S, N, and P. The adiabatic electron affinities (AEAs) and vertical detachment energies

(VDEs) of PNS, SPN, PSN, and cyc-PSN were calculated. The predicted AEA and VDE of the linear SPN isomer are large: 2.24 and 3.04 eV, respectively. The potential energy surfaces (PESs) of the lowest-lying electronic states of the SPN isomer along the PN and SP bond lengths and bond angle were mapped. A set of spectroscopic ...


Characterization Of Solution-Phase Drug-Protein Interactions By Ultrafast Affinity Extraction, Sandya Beeram, Xiwei Zheng, Kyungah Suh, David S. Hage Jan 2018

Characterization Of Solution-Phase Drug-Protein Interactions By Ultrafast Affinity Extraction, Sandya Beeram, Xiwei Zheng, Kyungah Suh, David S. Hage

Faculty Publications -- Chemistry Department

A number of tools based on high-performance affinity separations have been developed for studying drug-protein interactions. An example of one recent approach is ultrafast affinity extraction. This method has been employed to examine the free (or non-bound) fractions of drugs and other solutes in simple or complex samples that contain soluble binding agents. These free fractions have also been used to determine the binding constants and rate constants for the interactions of drugs with these soluble agents. This report describes the general principles of ultrafast affinity extraction and the experimental conditions under which it can be used to characterize such ...


Elastic Properties Of 2d Ti3c2tx Mxene Monolayers And Bilayers, Alexey Lipatov, Haidong Lu, Mohamed H. Alhabeb, Babak Anasori, Alexei Gruverman, Yury Gogotsi, Alexander Sinitskii Jan 2018

Elastic Properties Of 2d Ti3c2tx Mxene Monolayers And Bilayers, Alexey Lipatov, Haidong Lu, Mohamed H. Alhabeb, Babak Anasori, Alexei Gruverman, Yury Gogotsi, Alexander Sinitskii

Faculty Publications -- Chemistry Department

Two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, are a large class of materials that are finding numerous applications ranging from energy storage and electromagnetic interference shielding to water purification and antibacterial coatings. Yet, despite the fact thatmore than 20 different MXenes have been synthesized, the mechanical properties of a MXene monolayer have not been experimentally studied. We measured the elastic properties of monolayers and bilayers of the most important MXene material to date, Ti3C2Tx (Tx stands for surface termination).We developed amethod for preparingwell-strainedmembranes of Ti3C2Tx ...


Systems And Methods For Actuating Soft Robotic Actuators, Robert F. Shepherd, Adam Stokes, Stephen A. Morin, Ludovico Cademartiri, Jacob Freake, Rui Nunes, Xin Chen, George M. Whitesides Jan 2018

Systems And Methods For Actuating Soft Robotic Actuators, Robert F. Shepherd, Adam Stokes, Stephen A. Morin, Ludovico Cademartiri, Jacob Freake, Rui Nunes, Xin Chen, George M. Whitesides

Faculty Publications -- Chemistry Department

Systems and methods for providing a soft robot is provided. In one system , a robotic device includes a flexible body having a fluid chamber, where a portion of the flexible body includes an elastically extensible material and a portion of the flexible body is strain limiting relative to the elastically extensible material. The robotic device can further include a pressurizing inlet in fluid communication with the fluid chamber, and a pressurizing device in fluid communication with the pressurizing inlet, the pressurizing device including a reaction chamber configured to accommodate a gas producing chemical reaction for providing pressurized gas to the ...


Flexible Robotic Actuators, Stephen A. Morin, Robert F. Shepherd, Adam Stokes, Filip Ilievski, Ramses V. Martinez, Jamie L. Branch, Carina R. Fish, Lihua Jin, Rui M. D. Nunes, Zhigang Suo, George M. Whitesides Jan 2018

Flexible Robotic Actuators, Stephen A. Morin, Robert F. Shepherd, Adam Stokes, Filip Ilievski, Ramses V. Martinez, Jamie L. Branch, Carina R. Fish, Lihua Jin, Rui M. D. Nunes, Zhigang Suo, George M. Whitesides

Faculty Publications -- Chemistry Department

Systems and methods for providing flexible robotic actuators are disclosed. Some embodiments of the disclosed subject matter include a soft robot capable of providing a radial deflection motions; a soft tentacle actuator capable of providing a variety of motions and providing transportation means for various types of materials; and a hybrid robotic system that retains desirable characteristics of both soft robots and hard robots. Some embodiments of the disclosed subject matter also include methods for operating the dis closed robotic systems.


Application Of Group I Metal Adduction To The Separation Of Steroids By Traveling Wave Ion Mobility Spectrometry, Alana L. Rister, Tiana L. Martin, Eric D. Dodds Jan 2018

Application Of Group I Metal Adduction To The Separation Of Steroids By Traveling Wave Ion Mobility Spectrometry, Alana L. Rister, Tiana L. Martin, Eric D. Dodds

Faculty Publications -- Chemistry Department

Steroids represent an interesting class of small biomolecules due to their use as biomarkers and their status as scheduled drugs. Although the analysis of steroids is complicated by the potential for many isomers, ion mobility spectrometry (IMS) has previously shown promise for the rapid separation of steroid isomers. This work is aimed at the further development of IMS separation for the analysis of steroids. Here, traveling wave ion mobility spectrometry (TWIMS) was applied to the study of group I metal adducted steroids and their corresponding multimers for five sets of isomers. Each set of isomers had a minimum of one ...


Tin Nanoparticles Encapsulated Carbon Nanoboxes As High-Performance Anode For Lithium-Ion Batteries, Ziming Yang, Hong-Hui Wu, Zhiming Zheng, Yong Cheng, Pei Li, Qiaobao Zhang, Ming-Sheng Wang Jan 2018

Tin Nanoparticles Encapsulated Carbon Nanoboxes As High-Performance Anode For Lithium-Ion Batteries, Ziming Yang, Hong-Hui Wu, Zhiming Zheng, Yong Cheng, Pei Li, Qiaobao Zhang, Ming-Sheng Wang

Faculty Publications -- Chemistry Department

One of the crucial challenges for applying Sn as an anode of lithium-ion batteries (LIBs) is the dramatic volume change during lithiation/delithiation process, which causes a rapid capacity fading and then deteriorated battery performance. To address this issue, herein, we report the design and fabrication of Sn encapsulated carbon nanoboxes (denoted as Sn@C) with yolk@shell architectures. In this design, the carbon shell can facilitate the good transport kinetics whereas the hollow space between Sn and carbon shell can accommodate the volume variation during repeated charge/discharge process. Accordingly, this composite electrode exhibits a high reversible capacity of ...


Anatomy Of Stem Teaching In American Universities: A Snapshot From A Large-Scale Observation Study, Marilyne Stains, Jordan Harshman, Megan K. Barker, Stephanie V. Chasteen, Renee Cole, Sue Ellen Dechenne-Peters, M. Kevin Eagan Jr., Joan M. Esson, Jennifer K. Knight, Frank A. Laski, Marc Levis-Fitzgerald, Christopher J. Lee, Stanley M. Lo, Lisa M. Mcdonnell, Timothy A. Mckay, Nicole Michelotti, Michael S. Palmer, Kathryn M. Plank, Tamara M. Rodela, Erin R. Sanders, Natalie G. Schimpf, Patricia M. Schulte, Michelle Smith, Mackenzie Stetzer, Jackie Stewart, Blaire Van Valkenburgh, Erin Vinson, Laura K. Weir, Paul J. Wendel, Lindsay B. Wheeler, Anna M. Young Jan 2018

Anatomy Of Stem Teaching In American Universities: A Snapshot From A Large-Scale Observation Study, Marilyne Stains, Jordan Harshman, Megan K. Barker, Stephanie V. Chasteen, Renee Cole, Sue Ellen Dechenne-Peters, M. Kevin Eagan Jr., Joan M. Esson, Jennifer K. Knight, Frank A. Laski, Marc Levis-Fitzgerald, Christopher J. Lee, Stanley M. Lo, Lisa M. Mcdonnell, Timothy A. Mckay, Nicole Michelotti, Michael S. Palmer, Kathryn M. Plank, Tamara M. Rodela, Erin R. Sanders, Natalie G. Schimpf, Patricia M. Schulte, Michelle Smith, Mackenzie Stetzer, Jackie Stewart, Blaire Van Valkenburgh, Erin Vinson, Laura K. Weir, Paul J. Wendel, Lindsay B. Wheeler, Anna M. Young

Faculty Publications -- Chemistry Department

National and local initiatives focused on the transformation of STEM teaching in higher education have multiplied over the last decade. These initiatives often focus on measuring change in instructional practices, but it is difficult to monitor such change without a national picture of STEM educational practices, especially as characterized by common observational instruments. We characterized a snapshot of this landscape by conducting the first large scale observation-based study. We found that lecturing was prominent throughout the undergraduate STEM curriculum, even in classrooms with infrastructure designed to support active learning, indicating that further work is required to reform STEM education. Additionally ...


Magnetic Assembly Of Soft Robots With Hard Components, Sen Wai Kwok, Stephen A. Morin, Bobak Mosadegh, Ju-Hee So, Robert F. Shepherd, George M. Whitesides Jan 2018

Magnetic Assembly Of Soft Robots With Hard Components, Sen Wai Kwok, Stephen A. Morin, Bobak Mosadegh, Ju-Hee So, Robert F. Shepherd, George M. Whitesides

Faculty Publications -- Chemistry Department

Reconfigurable soft robotic actuators with hard components are described. Magnetic attraction is used to couple flexible molded bodies capable of actuation upon pressurization with other flexible molded bodies and/or with hard components (e.g., frames and connectors) to form a seal for fluidic communication and cooperative actuation. Pneumatic decoupling chambers built into the hard components to decouple the hard components from the magnetically-coupled soft molded bodies are described. The use of magnetic self- alignment coupling and pneumatic de-coupling allows for the remote assembly and disassembly of complex structures involving hard and soft components. The magnetic coupling allows for rapid ...


Flexible Thin Robotic Actuators, Aaron D. Mazzeo, Stephen A. Morin, Robert F. Shepherd, George M. Whitesides, William B. Kalb Jan 2018

Flexible Thin Robotic Actuators, Aaron D. Mazzeo, Stephen A. Morin, Robert F. Shepherd, George M. Whitesides, William B. Kalb

Faculty Publications -- Chemistry Department

Some embodiments of the disclosed subject matter includes a laminated robotic actuator. The laminated robotic actuator includes a strain-limiting layer comprising a flexible, non extensible material in the form of a sheet or thin film, a flexible inflatable layer in the form of a thin film or sheet in facing relationship with the strain-limiting layer, wherein the inflatable layer is selectively adhered to the strain-limiting layer, and wherein a portion of an un-adhered region between the strain-limiting layer and the inflatable layer defines a pressurizable channel, and at least one fluid inlet in fluid communication with the pressurizable channel. The ...


Crystallographic,Vibrational Modes And Optical Properties Data Of Α-Dipabcrystal, Ahmad Alsaad, Chris M. Marin, Nabil Alaqtash, Hsien-Wen Chao, Tsun-Hsu Chang, Chin Li Cheung, A. Ahmad, I. A. Qattan, Renat F. Sabirianov Jan 2018

Crystallographic,Vibrational Modes And Optical Properties Data Of Α-Dipabcrystal, Ahmad Alsaad, Chris M. Marin, Nabil Alaqtash, Hsien-Wen Chao, Tsun-Hsu Chang, Chin Li Cheung, A. Ahmad, I. A. Qattan, Renat F. Sabirianov

Faculty Publications -- Chemistry Department

The Crystallographic data of the α-DIPAB sample was measured using powder X-ray diffraction (PXRD). The crystal structure was also optimized using density functional based method. The calculations were performed both including vander Waals (vdW) interactions and excluding them to quantify the effects of vdW interaction on the crystal formation. The vibrational modes of DIPAB crystal corresponding to the Bromine deficient samples are calculated and presented. These show the origin of drastic change in dielectric response in Br deficient samples as compared to the ideal stoichiometric DIPAB crystal (Alsaad et al. 2018) [4]. Optical properties of an ideal α-DIPAB were calculated ...


Development Of Entrapment Columns For The Study Of Affinity Based Analysis Of Drug-Protein Interactions, Shiden T. Azaria Jul 2017

Development Of Entrapment Columns For The Study Of Affinity Based Analysis Of Drug-Protein Interactions, Shiden T. Azaria

Student Research Projects, Dissertations, and Theses - Chemistry Department

High-performance affinity chromatography (HPAC) is a type of liquid chromatography in which solutes are separated based on their binding to a stationary phase that is a biologically-related agent. Because of the strong and selective nature of many biological interactions, this method has already become a powerful technique for the purification and analysis of solutes that are complementary to the immobilized binding agent. Human serum albumin (HSA), the most abundant protein in the blood with concentrations of 35-50 mg/mL in serum, has interactions with many drugs, which can affect the absorption, distribution, metabolism and excretion of such agents.

The overall ...


The Future Of Nmr-Based Metabolomics, John L. Markley, Rafael Bruschweiler, Arthur S. Edison, Hamid R. Eghbalnia, Robert Powers, Daniel Raftery, David S. Wishart Jan 2017

The Future Of Nmr-Based Metabolomics, John L. Markley, Rafael Bruschweiler, Arthur S. Edison, Hamid R. Eghbalnia, Robert Powers, Daniel Raftery, David S. Wishart

Faculty Publications -- Chemistry Department

The two leading analytical approaches to metabolomics are mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. Although currently overshadowed by MS in terms of numbers of compounds resolved, NMR spectroscopy offers advantages both on its own and coupled with MS. NMR data are highly reproducible and quantitative over a wide dynamic range and are unmatched for determining structures of unknowns. NMR is adept at tracing metabolic pathways and fluxes using isotope labels. Moreover, NMR is non-destructive and can be utilized in vivo. NMR results have a proven track record of translating in vitro findings to in vivo clinical applications.


Amino Acid Catabolism In Staphylococcus Aureus And The Function Of Carbon Catabolite Repression, Cortney R. Halsey, Shulei Lei, Jacqueline K. Wax, Mckenzie K. Lehman, Austin S. Nuxoll, Laurey Steinke, Marat Sadykov, Robert Powers, Paul D. Fey Jan 2017

Amino Acid Catabolism In Staphylococcus Aureus And The Function Of Carbon Catabolite Repression, Cortney R. Halsey, Shulei Lei, Jacqueline K. Wax, Mckenzie K. Lehman, Austin S. Nuxoll, Laurey Steinke, Marat Sadykov, Robert Powers, Paul D. Fey

Faculty Publications -- Chemistry Department

Staphylococcus aureus must rapidly adapt to a variety of carbon and nitrogen sources during invasion of a host. Within a staphylococcal abscess, preferred carbon sources such as glucose are limiting, suggesting that S. aureus survives through the catabolism of secondary carbon sources. S. aureus encodes pathways to catabolize multiple amino acids, including those that generate pyruvate, 2-oxoglutarate, and oxaloacetate. To assess amino acid catabolism, S. aureus JE2 and mutants were grown in complete defined medium containing 18 amino acids but lacking glucose (CDM). A mutation in the gudB gene, coding for glutamate dehydrogenase, which generates 2-oxoglutarate from glutamate, significantly reduced ...


Fluorogenic Protein Labeling Using A Genetically Encoded Unstrained Alkene, Xin Shang, X. Song, C. Faller, R. Lai, H. Li, R. Cerny, Wei Niu, Jiantao Guo Jan 2017

Fluorogenic Protein Labeling Using A Genetically Encoded Unstrained Alkene, Xin Shang, X. Song, C. Faller, R. Lai, H. Li, R. Cerny, Wei Niu, Jiantao Guo

Faculty Publications -- Chemistry Department

We developed a new fluorogenic bioorthogonal reaction that is based on the inverse electron-demand Diels–Alder reaction between styrene (an unstrained alkene) and a simple tetrazine. The reaction forms a new fluorophore with no literature precedent. We have identified an aminoacyl-tRNA synthetase/tRNA pair for the efficient and site-specific incorporation of a styrene-containing amino acid into proteins in response to amber nonsense codon. Fluorogenic labeling of purified proteins and intact proteins in live cells were demonstrated. The fluorogenicity of the styrene–tetrazine reaction can be potentially applied to the study of protein folding and function under physiological conditions with low ...


Fidelity Of Implementation: An Overlooked Yet Critical Construct To Establish Effectiveness Of Evidence-Based Instructional Practices, Marilyne Stains, Trisha Vickrey Jan 2017

Fidelity Of Implementation: An Overlooked Yet Critical Construct To Establish Effectiveness Of Evidence-Based Instructional Practices, Marilyne Stains, Trisha Vickrey

Faculty Publications -- Chemistry Department

The discipline-based education research (DBER) community has been invested in the research and development of evidence-based instructional practices (EBIPs) for decades. Unfortunately, investigations of the impact of EBIPs on student outcomes typically do not characterize instructors’ adherence to an EBIP, often assuming that implementation was as intended by developers. The validity of such findings is compromised, since positive or negative outcomes can be incorrectly attributed to an EBIP when other factors impacting implementation are often present. This methodological flaw can be overcome by developing measures to determine the fidelity of implementation (FOI) of an intervention, a construct extensively studied in ...


Fluorogenic Protein Labeling Using A Genetically Encoded Unstrained Alkene, X. Shang, X. Song, C. Faller, R. Lai, H. Li, Ronald Cerny, Wei Niu, Jiantao Guo Jan 2017

Fluorogenic Protein Labeling Using A Genetically Encoded Unstrained Alkene, X. Shang, X. Song, C. Faller, R. Lai, H. Li, Ronald Cerny, Wei Niu, Jiantao Guo

Faculty Publications -- Chemistry Department

We developed a new fluorogenic bioorthogonal reaction that is based on the inverse electron-demand Diels–Alder reaction between styrene (an unstrained alkene) and a simple tetrazine. The reaction forms a new fluorophore with no literature precedent. We have identified an aminoacyl-tRNA synthetase/tRNA pair for the efficient and site-specific incorporation of a styrene-containing amino acid into proteins in response to amber nonsense codon. Fluorogenic labeling of purified proteins and intact proteins in live cells were demonstrated. The fluorogenicity of the styrene–tetrazine reaction can be potentially applied to the study of protein folding and function under physiological conditions with low ...


Cytotoxic Polyketides With An Oxygen-Bridged Cyclooctadiene Core Skeleton From The Mangrove Endophytic Fungus Phomosis Sp. A818, Wei Zhang, Baobing Zhao, Liangcheng Du, Yuemao Shen Jan 2017

Cytotoxic Polyketides With An Oxygen-Bridged Cyclooctadiene Core Skeleton From The Mangrove Endophytic Fungus Phomosis Sp. A818, Wei Zhang, Baobing Zhao, Liangcheng Du, Yuemao Shen

Faculty Publications -- Chemistry Department

Plant endophytic microorganisms represent a largely untapped resource for new bioactive natural products. Eight polyketide natural products were isolated from a mangrove endophytic fungus Phomosis sp. A818. The structural elucidation of these compounds revealed that they share a distinct feature in their chemical structures, an oxygen-bridged cyclooctadiene core skeleton. The study on their structure–activity relationship showed that the α,β-unsaturated δ-lactone moiety, as exemplified in compounds 1 and 2, was critical to the cytotoxic activity of these compounds. In addition, compound 4 might be a potential agonist of AMPK (5'-adenosine monophosphate-activated protein kinase).


Chemoselective Alteration Of Fluorophore Scaffolds As A Strategy For The Development Of Ratiometric Chemodosimeters, Xinqi Zhou, Lauren Lesiak, Rui Lai, Jon R. Beck, Jia Zhao, Christian Elowsky, Hui Li, Cliff I. Stains Jan 2017

Chemoselective Alteration Of Fluorophore Scaffolds As A Strategy For The Development Of Ratiometric Chemodosimeters, Xinqi Zhou, Lauren Lesiak, Rui Lai, Jon R. Beck, Jia Zhao, Christian Elowsky, Hui Li, Cliff I. Stains

Faculty Publications -- Chemistry Department

Ratiometric sensors generally couple binding events or chemical reactions at a distal site to changes in the fluorescence of a core fluorophore scaffold. However, such approaches are often hindered by spectral overlap of the product and reactant species. We provide a strategy to design ratiometric sensors that display dramatic spectral shifts by leveraging the chemoselective reactivity of novel functional groups inserted within fluorophore scaffolds. As a proof-of-principle, fluorophores containing a borinate (RF620) or silanediol (SiOH2R) functionality at the bridging position of the xanthene ring system are developed as endogenous H2O2 sensors. Both these fluorophores display far-red ...


Laterally Extended Atomically Precise Graphene Nanoribbons With Improved Electrical Conductivity For Efficient Gas Sensing, Mohammad Mehdi Pour, Andrey Lashkov, Adrian Radocea, Ximeng Liu, Tao Sun, Alexey Lipatov, Rafal A. Korlacki, Mikhail Shekhirev, Narayana R. Aluru, Joseph W. Lyding, Victor Sysoev, Alexander Sinitskii Jan 2017

Laterally Extended Atomically Precise Graphene Nanoribbons With Improved Electrical Conductivity For Efficient Gas Sensing, Mohammad Mehdi Pour, Andrey Lashkov, Adrian Radocea, Ximeng Liu, Tao Sun, Alexey Lipatov, Rafal A. Korlacki, Mikhail Shekhirev, Narayana R. Aluru, Joseph W. Lyding, Victor Sysoev, Alexander Sinitskii

Faculty Publications -- Chemistry Department

Narrow atomically precise graphene nanoribbons hold great promise for electronic and optoelectronic applications, but the previously demonstrated nanoribbon-based devices typically suffer from low currents and mobilities. In this study, we explored the idea of lateral extension of graphene nanoribbons for improving their electrical conductivity. We started with a conventional chevron graphene nanoribbon, and designed its laterally extended variant. We synthesized these new graphene nanoribbons in solution and found that the lateral extension results in decrease of their electronic bandgap and improvement in the electrical conductivity of nanoribbon-based thin films. These films were employed in gas sensors and an electronic nose ...


Nanomaterials As Stationary Phases And Supports In Liquid Chromatography: A Review, Sandya Beeram, Elliott Rodriguez, Suresh Doddavenkatanna, Zhao Li, Allegra Pekarek, Darin Peev, Kathryn Goerl, Gianfranco Trovato, Tino Hofmann, David S. Hage Jan 2017

Nanomaterials As Stationary Phases And Supports In Liquid Chromatography: A Review, Sandya Beeram, Elliott Rodriguez, Suresh Doddavenkatanna, Zhao Li, Allegra Pekarek, Darin Peev, Kathryn Goerl, Gianfranco Trovato, Tino Hofmann, David S. Hage

Faculty Publications -- Chemistry Department

The development of various nanomaterials over the last few decades has led to many applications for these materials in liquid chromatography (LC). This review will look at the types of nanomaterials that have been incorporated into LC systems and the applications that have been explored for such systems. A number of carbon-based nanomaterials and inorganic nanomaterials have been considered for use in LC, ranging from carbon nanotubes, fullerenes and nanodiamonds to metal nanoparticles and nanostructures based on silica, alumina, zirconia and titanium dioxide. Many ways have been described for incorporating these nanomaterials into LC systems. These methods have included covalent ...


Soft Robotic Actuators, Filip Ilievski, Xin Chen, Aaron D. Mazzeo, George M. Whitesides, Robert F. Shepherd, Ramses V. Martinez, Won Jae Choi, Sen Wai Kwok, Stephen A. Morin, Adam Stokes, Zhihong Nie Jan 2017

Soft Robotic Actuators, Filip Ilievski, Xin Chen, Aaron D. Mazzeo, George M. Whitesides, Robert F. Shepherd, Ramses V. Martinez, Won Jae Choi, Sen Wai Kwok, Stephen A. Morin, Adam Stokes, Zhihong Nie

Faculty Publications -- Chemistry Department

A soft robotic device includes a flexible body having a width, a length and a thickness, wherein the thickness is at least 1 mm, the flexible body having at least one channel disposed within the flexible body, the channel defined by upper, lower and side walls, wherein at least one wall is strain limiting; and a pressurizing inlet in fluid communication with the at least one channel, the at least one channel positioned and arranged such that the wall opposite the strain limiting wall preferentially expands when the soft robotic device is pressurized through the inlet.