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Articles 1 - 30 of 51
Full-Text Articles in Physics
Breaking The Causality Limit For Broadband Acoustic Absorption Using A Noncausal Active Absorber, Kangkang Wang, Sipei Zhao, Chen Shen, Haishan Zou, Jing Lu, Andrea Alu
Breaking The Causality Limit For Broadband Acoustic Absorption Using A Noncausal Active Absorber, Kangkang Wang, Sipei Zhao, Chen Shen, Haishan Zou, Jing Lu, Andrea Alu
Henry M. Rowan College of Engineering Departmental Research
The principle of causality imposes a constraint between the thickness and bandwidth of absorbers. This trade-off applies to any linear, time-invariant, passive system, limiting the development of broadband-absorbing materials that demand a thin profile for sound, light, and radio waves. Here, we demonstrate a strategy to overcome this constraint in acoustics using a noncausal active absorber whose response is controlled over time. A theoretical framework is established, which sets a relation among minimum thickness, bandwidth, and a priori information about the incident signal, representing a relaxed physical bound for noncausal absorbers. We design an absorber based on this principle and …
Revolutionizing Wild Silk Fibers: Ultrasound Enhances Structure, Properties, And Regenerability Of Protein Biomaterials In Ionic Liquids., Xincheng Zhuang, Haomiao Zhu, Fang Wang, Xiao Hu
Revolutionizing Wild Silk Fibers: Ultrasound Enhances Structure, Properties, And Regenerability Of Protein Biomaterials In Ionic Liquids., Xincheng Zhuang, Haomiao Zhu, Fang Wang, Xiao Hu
College of Science & Mathematics Departmental Research
Ultrasound-assisted regulation of biomaterial properties has attracted increasing attention due to the unique reaction conditions induced by ultrasound cavitation. In this study, we explored the fabrication of wild tussah silk nanofiber membranes via ultrasound spray spinning from an ionic liquid system, characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), atomic force microscopy (AFM), water contact angle, cytocompatibility tests, and enzymatic degradation studies. We investigated the effects of ultrasound propagation in an ionic liquid on the morphology, structure, thermal and mechanical properties, surface hydrophilicity, biocompatibility, and biodegradability …
Electrochromic Polymers: From Electrodeposition To Hybrid Solid Devices, Haradou Sare, Dongmei Dong
Electrochromic Polymers: From Electrodeposition To Hybrid Solid Devices, Haradou Sare, Dongmei Dong
College of Science & Mathematics Departmental Research
This paper reports on the linear colorimetric and electrochromic (EC) characteristics of electrodeposited polyaniline (PANI) films. This paper also investigates the infrared EC properties of acid-doped PANI films. The electrochemical polymerization method was employed to create a porous and thin PANI film layer onto PET-ITO substrates. This layer was capped with WO3 film to create a gel electrolyte sandwich structure that demonstrates the compatibility of PANI films with cathodic WO3 films in full devices. The electrodeposition of the film was fabricated by applying different voltages and time, with the optimal film quality achieved with the 1.7 V voltage and a …
Development Of Antibacterial Neural Stimulation Electrodes Via Hierarchical Surface Restructuring And Atomic Layer Deposition., Henna Khosla, Wesley Seche, Daniel Ammerman, Sahar Elyahoodayan, Gregory A. Caputo, Jeffrey Hettinger, Shahram Amini, Gang Feng
Development Of Antibacterial Neural Stimulation Electrodes Via Hierarchical Surface Restructuring And Atomic Layer Deposition., Henna Khosla, Wesley Seche, Daniel Ammerman, Sahar Elyahoodayan, Gregory A. Caputo, Jeffrey Hettinger, Shahram Amini, Gang Feng
College of Science & Mathematics Departmental Research
Miniaturization and electrochemical performance enhancement of electrodes and microelectrode arrays in emerging long-term implantable neural stimulation devices improves specificity, functionality, and performance of these devices. However, surgical site and post-implantation infections are amongst the most devastating complications after surgical procedures and implantations. Additionally, with the increased use of antibiotics, the threat of antibiotic resistance is significant and is increasingly being recognized as a global problem. Therefore, the need for alternative strategies to eliminate post-implantation infections and reduce antibiotic use has led to the development of medical devices with antibacterial properties. In this work, we report on the development of electrochemically …
Effect Of Hf Alloying On Magnetic, Structural, And Magnetostrictive Properties In Feco Films For Magnetoelectric Heterostructure Devices, Thomas Mion, Margo Staruch, Konrad Bussmann, Goran Karapetrov, Olaf Van 'T Erve, Sara Mills, Heonjune Ryou, Ramasis Goswami, Patrick G. Callahan, David J. Rowenhorst, Syed B. Qadri, Samuel Lofland, Peter Finkel
Effect Of Hf Alloying On Magnetic, Structural, And Magnetostrictive Properties In Feco Films For Magnetoelectric Heterostructure Devices, Thomas Mion, Margo Staruch, Konrad Bussmann, Goran Karapetrov, Olaf Van 'T Erve, Sara Mills, Heonjune Ryou, Ramasis Goswami, Patrick G. Callahan, David J. Rowenhorst, Syed B. Qadri, Samuel Lofland, Peter Finkel
College of Science & Mathematics Departmental Research
Materials with high magnetoelectric coupling are attractive for use in engineered multiferroic heterostructures with applications such as ultra-low power magnetic sensors, parametric inductors, and non-volatile random-access memory devices. Iron-cobalt alloys exhibit both high magnetostriction and high saturation magnetization that are required for achieving significantly higher magnetoelectric coupling. We report on sputter-deposited (Fe0.5Co0.5)1-xHfx (x = 0 - 0.14) alloy thin films and the beneficial influence of Hafnium alloying on the magnetic and magnetostrictive properties. We found that co-sputtering Hf results in the realization of the peening mechanism that drives film stress from highly tensile to slightly compressive. Scanning electron microscopy and …
Developing Carbon Quantum Dots As Multimodal Contrast Agents, Nicholas Whiting
Developing Carbon Quantum Dots As Multimodal Contrast Agents, Nicholas Whiting
College of Science & Mathematics Departmental Research
No abstract provided.
Reconversion Of Parahydrogen Gas In Surfactant-Coated Glass Nmr Tubes, Robert V. Chimenti, James Daley, James Sack, Jennifer Necsutu, Nicholas Whiting
Reconversion Of Parahydrogen Gas In Surfactant-Coated Glass Nmr Tubes, Robert V. Chimenti, James Daley, James Sack, Jennifer Necsutu, Nicholas Whiting
College of Science & Mathematics Departmental Research
The application of parahydrogen gas to enhance the magnetic resonance signals of a diversity of chemical species has increased substantially in the last decade. Parahydrogen is prepared by lowering the temperature of hydrogen gas in the presence of a catalyst; this enriches the para spin isomer beyond its normal abundance of 25% at thermal equilibrium. Indeed, parahydrogen fractions that approach unity can be attained at sufficiently low temperatures. Once enriched, the gas will revert to its normal isomeric ratio over the course of hours or days, depending on the surface chemistry of the storage container. Although parahydrogen enjoys long lifetimes …
Ultrasound-Assisted Air-Jet Spinning Of Silk Fibroin-Soy Protein Nanofiber Composite Biomaterials., Futian Yang, Fang Wang, Janine Mazahreh, Xiao Hu
Ultrasound-Assisted Air-Jet Spinning Of Silk Fibroin-Soy Protein Nanofiber Composite Biomaterials., Futian Yang, Fang Wang, Janine Mazahreh, Xiao Hu
College of Science & Mathematics Departmental Research
Ultrasound utilizes a non-radiation technology that can meet modern standards to gain access to cheap, reliable and sustainable modern energy. Ultrasound technology can be implemented in the field of biomaterials for its exceptional potential in controlling the shape of nanomaterials. This study presents the first example of the production of soy and silk fibroin protein composite nanofibers in various ratios via combining ultrasonic technology with air-spray spinning. Characterization of ultrasonic spun nanofibers was performed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, water contact angle, water retention, enzymatic …
Online Test Administration Results In Students Selecting More Responses To Multiple-Choice-Multiple-Response Items, Alexis Olsho, Trevor Smith, Philip Eaton, Charlotte Zimmerman, Andrew Boudreaux, Suzanne White
Online Test Administration Results In Students Selecting More Responses To Multiple-Choice-Multiple-Response Items, Alexis Olsho, Trevor Smith, Philip Eaton, Charlotte Zimmerman, Andrew Boudreaux, Suzanne White
College of Science & Mathematics Departmental Research
We developed the Physics Inventory of Quantitative Literacy (PIQL) to assess students' quantitative reasoning in introductory physics contexts. The PIQL includes several "multiple-choice-multiple-response"(MCMR) items (i.e., multiple-choice questions for which more than one response may be selected) as well as traditional single-response multiple-choice items. In this paper, we discuss differences in performance on MCMR items that seems to result from differences in administration method (paper versus online). In particular, we find a tendency for "clickiness"in online administration: students choose more responses to MCMR items when taking the electronic version of the assessment. Student performance on single-response multiple-choice items was not affected …
Editorial: Advances In Acoustic/Elastic Wave Sensing For Information Processing, Taehwa Lee, Chen Shen, Qingbo He
Editorial: Advances In Acoustic/Elastic Wave Sensing For Information Processing, Taehwa Lee, Chen Shen, Qingbo He
Henry M. Rowan College of Engineering Departmental Research
No abstract provided.
Role Of Draw Rate And Molecular Weight When Electrospun Nanofibers Are Post-Drawn With Residual Solvent, Adriano Conte, Xiao Hu, Vincent Beachley
Role Of Draw Rate And Molecular Weight When Electrospun Nanofibers Are Post-Drawn With Residual Solvent, Adriano Conte, Xiao Hu, Vincent Beachley
College of Science & Mathematics Departmental Research
The postdrawing process is poorly understood for polymer nanofibers due to the difficulty of manipulating nanofiber structures. Here, an angled track system facilitates postdrawing of individual nanofibers with control of parameters including molecular weight, draw rate, draw ratio, and solvent evaporation time. In this study, the effects of molecular weight, draw rate, and relative residual solvent content on final nanofiber properties are investigated. Molecular weight is first investigated to clarify any influence polymer chain length can have on drawing in facilitating or hindering chain extensibility. Polyacrylonitrile nanofibers with 50 and 150 kDa molecular weights behave similarly with postdrawing resulting in …
Multifunctional Silk Fibroin – Poly(L-Lactic Acid) Porous Nanofibers: Designing Adjustable Nanopores To Control Composite Properties And Biological Responses, Hangling Gu, Fang Wang, Hao Liu, Kyle Printon, Xiao Hu
Multifunctional Silk Fibroin – Poly(L-Lactic Acid) Porous Nanofibers: Designing Adjustable Nanopores To Control Composite Properties And Biological Responses, Hangling Gu, Fang Wang, Hao Liu, Kyle Printon, Xiao Hu
College of Science & Mathematics Departmental Research
Nano-scale renewable porous materials have a wide range of applications in the biomedical field such as tissue engineering and biosensors due to their high biocompatibility and large surface area. In this study, a composite of silk fibroin and poly(L-lactic acid) was electrospun together to form a porous nanofiber biomaterial with 11 blending ratios to tune the porosity of the single fibers (19.3–49%). This is highly advantageous as porous fibers effectively promoted cell attachment and proliferation while also manipulating cell growth. The protein-polymer molecular interactions, structures and crystal contents, as well as the melting and glass transition behaviors of the composites …
Controlling The Structure And Properties Of Semi-Crystalline Cellulose/Silk-Fibroin Biocomposites By Ionic Liquid Type And Hydrogen Peroxide Concentration, Stacy A. Love, Xiao Hu, David Salas-De La Cruz
Controlling The Structure And Properties Of Semi-Crystalline Cellulose/Silk-Fibroin Biocomposites By Ionic Liquid Type And Hydrogen Peroxide Concentration, Stacy A. Love, Xiao Hu, David Salas-De La Cruz
College of Science & Mathematics Departmental Research
This work reports how to tune the semi-crystallinity of a blended microcrystalline cellulose/silk-fibroin biocomposite using ionic liquids and various coagulation agents. The morphological and thermal properties of a blended 1:1 polymeric system are studied as a function of polymer fabrication parameters. Ionic liquids, 1-ethyl-3-methylimidazolium acetate verses 1-ethyl-3-methylimidazolium chloride, are used as competing solvent types and six hydrogen peroxide solutions (1—25%) plus water are used as varying coagulation agents. Analysis of the results demonstrate that solvent anion type, Ac− verses Cl−, affects protein secondary structure formation, and that solvent anion type and the concentration of hydrogen peroxide changes morphology and thermal …
Post-Acquisition Hyperpolarized 29silicon Mr Image Processing For Visualization Of Colorectal Lesions Using A User-Friendly Graphical Interface, Caitlin V Mccowan, Duncan Salmon, Jingzhe Hu, Shivanand Pudakalakatti, Nicholas Whiting, Jennifer S Davis, Daniel D Carson, Niki M Zacharias, Pratip K Bhattacharya, Mary C Farach-Carson
Post-Acquisition Hyperpolarized 29silicon Mr Image Processing For Visualization Of Colorectal Lesions Using A User-Friendly Graphical Interface, Caitlin V Mccowan, Duncan Salmon, Jingzhe Hu, Shivanand Pudakalakatti, Nicholas Whiting, Jennifer S Davis, Daniel D Carson, Niki M Zacharias, Pratip K Bhattacharya, Mary C Farach-Carson
College of Science & Mathematics Departmental Research
Medical imaging devices often use automated processing that creates and displays a self-normalized image. When improperly executed, normalization can misrepresent information or result in an inaccurate analysis. In the case of diagnostic imaging, a false positive in the absence of disease, or a negative finding when disease is present, can produce a detrimental experience for the patient and diminish their health prospects and prognosis. In many clinical settings, a medical technical specialist is trained to operate an imaging device without sufficient background information or understanding of the fundamental theory and processes involved in image creation and signal processing. Here, we …
Recent Progress In Biopolymer-Based Hydrogel Materials For Biomedical Applications., Ayaz Mahmood, Dev Patel, Brandon Hickson, John Desrochers, Xiao Hu
Recent Progress In Biopolymer-Based Hydrogel Materials For Biomedical Applications., Ayaz Mahmood, Dev Patel, Brandon Hickson, John Desrochers, Xiao Hu
College of Science & Mathematics Departmental Research
Hydrogels from biopolymers are readily synthesized, can possess various characteristics for different applications, and have been widely used in biomedicine to help with patient treatments and outcomes. Polysaccharides, polypeptides, and nucleic acids can be produced into hydrogels, each for unique purposes depending on their qualities. Examples of polypeptide hydrogels include collagen, gelatin, and elastin, and polysaccharide hydrogels include alginate, cellulose, and glycosaminoglycan. Many different theories have been formulated to research hydrogels, which include Flory-Rehner theory, Rubber Elasticity Theory, and the calculation of porosity and pore size. All these theories take into consideration enthalpy, entropy, and other thermodynamic variables so that …
Ultrasound Regulated Flexible Protein Materials: Fabrication, Structure And Physical-Biological Properties., Bowen Cai, Hanling Gu, Fang Wang, Kyle Printon, Zhenggui Gu, Xiao Hu
Ultrasound Regulated Flexible Protein Materials: Fabrication, Structure And Physical-Biological Properties., Bowen Cai, Hanling Gu, Fang Wang, Kyle Printon, Zhenggui Gu, Xiao Hu
College of Science & Mathematics Departmental Research
Ultrasound can be used in the biomaterial field due to its high efficiency, easy operation, no chemical treatment, repeatability and high level of control. In this work, we demonstrated that ultrasound is able to quickly regulate protein structure at the solution assembly stage to obtain the designed properties of protein-based materials. Silk fibroin proteins dissolved in a formic acid-CaCl solution system were treated in an ultrasound with varying times and powers. By altering these variables, the silks physical properties and structures can be fine-tuned and the results were investigated with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron …
Structural And Morphological Properties Of Wool Keratin And Cellulose Biocomposites Fabricated Using Ionic Liquids, Karleena Rybacki, Stacy A. Love, Bailey Blessing, Abneris Morales, Emily Mcdermott, Kaylyn Cai, Xiao Hu, David Salas-De La Cruz
Structural And Morphological Properties Of Wool Keratin And Cellulose Biocomposites Fabricated Using Ionic Liquids, Karleena Rybacki, Stacy A. Love, Bailey Blessing, Abneris Morales, Emily Mcdermott, Kaylyn Cai, Xiao Hu, David Salas-De La Cruz
College of Science & Mathematics Departmental Research
In this study, the structural, thermal, and morphological properties of biocomposite films composed of wool keratin mixed with cellulose and regenerated with ionic liquids and various coagulation agents were characterized and explored. These blended films exhibit different physical and thermal properties based on the polymer ratio and coagulation agent type in the fabrication process. Thus, understanding their structure and molecular interaction will enable an understanding of how the crystallinity of cellulose can be modified in order to understand the formation of protein secondary structures. The thermal, morphological, and physiochemical properties of the biocomposites were investigated by Fourier transform infrared (FTIR) …
Replicating Analyses Of Item Response Curves Using Data From The Force And Motion Conceptual Evaluation, Connor J. Richardson, Trevor Smith, Paul J. Walter
Replicating Analyses Of Item Response Curves Using Data From The Force And Motion Conceptual Evaluation, Connor J. Richardson, Trevor Smith, Paul J. Walter
College of Science & Mathematics Departmental Research
Ishimoto, Davenport, and Wittmann have previously reported analyses of data from student responses to the Force and Motion Conceptual Evaluation (FMCE), in which they used item response curves (IRCs) to make claims about American and Japanese students’ relative likelihood to choose certain incorrect responses to some questions. We have used an independent dataset of over 6,500 American students’ responses to the FMCE to generate IRCs to test their claims. Converting the IRCs to vectors, we used dot product analysis to compare each response item quantitatively. For most questions, our analyses are consistent with Ishimoto, Davenport, and Wittmann, with some results …
Air-Spun Silk-Based Micro-/Nanofibers And Thin Films For Drug Delivery, Christopher R Gough, Xiao Hu
Air-Spun Silk-Based Micro-/Nanofibers And Thin Films For Drug Delivery, Christopher R Gough, Xiao Hu
College of Science & Mathematics Departmental Research
Micro-/nanofibers have shown high promise as drug delivery vehicles due to their high porosity and surface-area-to-volume ratio. The current study utilizes air-spraying, a novel fiber fabrication technique, to create silk micro-/nanofibers without the need for a high voltage power source. Air-spraying was used to create silk fibrous mats embedded with several model drugs with high efficiency. In order to compare the effect of biomaterial geometry on the release of the model drugs, silk films were also created and characterized. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and a drug release study were …
Silk-Cellulose Acetate Biocomposite Materials Regenerated From Ionic Liquid, Ashley Rivera-Galetti, Chrtstopher R. Gough, Farhan Kaleem, Michael Burch, Chris Ratcliffe, Ping Lu, David Salas-De La Cruz, Xiao Hu
Silk-Cellulose Acetate Biocomposite Materials Regenerated From Ionic Liquid, Ashley Rivera-Galetti, Chrtstopher R. Gough, Farhan Kaleem, Michael Burch, Chris Ratcliffe, Ping Lu, David Salas-De La Cruz, Xiao Hu
College of Science & Mathematics Departmental Research
The novel use of ionic liquid as a solvent for biodegradable and natural organic biomaterials has increasingly sparked interest in the biomedical field. As compared to more volatile traditional solvents that rapidly degrade the protein molecular weight, the capability of polysaccharides and proteins to dissolve seamlessly in ionic liquid and form fine and tunable biomaterials after regeneration is the key interest of this study. Here, a blended system consisting of Bombyx Mori silk fibroin protein and a cellulose derivative, cellulose acetate (CA), in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIMAc) was regenerated and underwent characterization to understand the structure and physical …
Protein And Polysaccharide-Based Electroactive And Conductive Materials For Biomedical Applications, Xiao Hu, Samuel Ricci, Sebastian Naranjo Naranjo, Zachary Hill, Peter Gawason
Protein And Polysaccharide-Based Electroactive And Conductive Materials For Biomedical Applications, Xiao Hu, Samuel Ricci, Sebastian Naranjo Naranjo, Zachary Hill, Peter Gawason
College of Science & Mathematics Departmental Research
Electrically responsive biomaterials are an important and emerging technology in the fields of biomedical and material sciences. A great deal of research explores the integral role of electrical conduction in normal and diseased cell biology, and material scientists are focusing an even greater amount of attention on natural and hybrid materials as sources of biomaterials which can mimic the properties of cells. This review establishes a summary of those efforts for the latter group, detailing the current materials, theories, methods, and applications of electrically conductive biomaterials fabricated from protein polymers and polysaccharides. These materials can be used to improve human …
Selection Rule For Topological Amplifiers In Bogoliubov De Gennes Systems, Hong Y. Ling, Ben Kain
Selection Rule For Topological Amplifiers In Bogoliubov De Gennes Systems, Hong Y. Ling, Ben Kain
College of Science & Mathematics Departmental Research
Dynamical instability is an inherent feature of bosonic systems described by the Bogoliubov de Geenes (BdG) Hamiltonian. Since it causes the BdG system to collapse, it is generally thought that it should be avoided. Recently, there has been much effort to harness this instability for the benefit of creating a topological amplifier with stable bulk bands but unstable edge modes which can be populated at an exponentially fast rate. We present a theorem for determining the stability of states with energies sufficiently away from zero, in terms of an unconventional commutator between the number conserving part and number nonconserving part …
Chemical, Thermal, Time, And Enzymatic Stability Of Silk Materials With Silk I Structure, Meihui Zhao, Zhenzhen Qi, Xiaosheng Tao, Chad Newkirk, Xiao Hu, Shenzhou Lu
Chemical, Thermal, Time, And Enzymatic Stability Of Silk Materials With Silk I Structure, Meihui Zhao, Zhenzhen Qi, Xiaosheng Tao, Chad Newkirk, Xiao Hu, Shenzhou Lu
College of Science & Mathematics Departmental Research
The crystalline structure of silk fibroin Silk I is generally considered to be a metastable structure; however, there is no definite conclusion under what circumstances this crystalline structure is stable or the crystal form will change. In this study, silk fibroin solution was prepared from B. Mori silkworm cocoons, and a combined method of freeze-crystallization and freeze-drying at different temperatures was used to obtain stable Silk I crystalline material and uncrystallized silk material, respectively. Different concentrations of methanol and ethanol were used to soak the two materials with different time periods to investigate the effect of immersion treatments on the …
Dual-Crystallizable Silk Fibroin/Poly(L-Lactic Acid) Biocomposite Films: Effect Of Polymer Phases On Protein Structures In Protein-Polymer Blends, Fang Wang, Yingying Li, Christopher R. Gough, Qichun Liu, Xiao Hu
Dual-Crystallizable Silk Fibroin/Poly(L-Lactic Acid) Biocomposite Films: Effect Of Polymer Phases On Protein Structures In Protein-Polymer Blends, Fang Wang, Yingying Li, Christopher R. Gough, Qichun Liu, Xiao Hu
College of Science & Mathematics Departmental Research
Biopolymer composites based on silk fibroin have shown widespread potential due to their brilliant applications in tissue engineering, medicine and bioelectronics. In our present work, biocomposite nanofilms with different special topologies were obtained through blending silk fibroin with crystallizable poly(L-lactic acid) (PLLA) at various mixture rates using a stirring-reflux condensation blending method. The microstructure, phase components, and miscibility of the blended films were studied through thermal analysis in combination with Fourier-transform infrared spectroscopy and Raman analysis. X-ray diffraction and scanning electron microscope were also used for advanced structural analysis. Furthermore, their conformation transition, interaction mechanism, and thermal stability were also …
Protein Conformational Entropy Is Not Slaved To Water, Bryan S Marques, Matthew A Stetz, Christine Jorge, Kathleen G Valentine, A Joshua Wand, Nathaniel V Nucci
Protein Conformational Entropy Is Not Slaved To Water, Bryan S Marques, Matthew A Stetz, Christine Jorge, Kathleen G Valentine, A Joshua Wand, Nathaniel V Nucci
College of Science & Mathematics Departmental Research
Conformational entropy can be an important element of the thermodynamics of protein functions such as the binding of ligands. The observed role for conformational entropy in modulating molecular recognition by proteins is in opposition to an often-invoked theory for the interaction of protein molecules with solvent water. The "solvent slaving" model predicts that protein motion is strongly coupled to various aspects of water such as bulk solvent viscosity and local hydration shell dynamics. Changes in conformational entropy are manifested in alterations of fast internal side chain motion that is detectable by NMR relaxation. We show here that the fast-internal side …
Comparative Study Of Silk-Based Magnetic Materials: Effect Of Magnetic Particle Types On The Protein Structure And Biomaterial Properties., Ye Xue, Samuel Lofland, Xiao Hu
Comparative Study Of Silk-Based Magnetic Materials: Effect Of Magnetic Particle Types On The Protein Structure And Biomaterial Properties., Ye Xue, Samuel Lofland, Xiao Hu
College of Science & Mathematics Departmental Research
This study investigates combining the good biocompatibility and flexibility of silk protein with three types of widely used magnetic nanoparticles to comparatively explore their structures, properties and potential applications in the sustainability and biomaterial fields. The secondary structure of silk protein was quantitatively studied by infrared spectroscopy. It was found that magnetite (Fe3O4) and barium hexaferrite (BaFe12O19) can prohibit β-sheet crystal due to strong coordination bonding between Fe3+ ions and carboxylate ions on silk fibroin chains where cobalt particles showed minimal effect. This was confirmed by thermal analysis, where a high temperature degradation peak was found above 640 °C in …
Sound Vortex Diffraction Via Topological Charge In Phase Gradient Metagratings, Yangyang Fu, Chen Shen, Xiaohui Zhu, Junfei Li, Youwen Liu, Steven A. Crummer
Sound Vortex Diffraction Via Topological Charge In Phase Gradient Metagratings, Yangyang Fu, Chen Shen, Xiaohui Zhu, Junfei Li, Youwen Liu, Steven A. Crummer
Henry M. Rowan College of Engineering Departmental Research
Wave fields with orbital angular momentum (OAM) have been widely investigated in metasurfaces. By engineering acoustic metasurfaces with phase gradient elements, phase twisting is commonly used to obtain acoustic OAM. However, it has limited ability to manipulate sound vortices, and a more powerful mechanism for sound vortex manipulation is strongly desired. Here, we propose the diffraction mechanism to manipulate sound vortices in a cylindrical waveguide with phase gradient metagratings (PGMs). A sound vortex diffraction law is theoretically revealed based on the generalized conservation principle of topological charge. This diffraction law can explain and predict the complicated diffraction phenomena of sound …
Divergence Of The Dielectric Constant In Ultrathin Granular Metal Films Near The Percolation Threshold, H. Bakkali, E. Blanco, Samuel Lofland, M. Dominguez
Divergence Of The Dielectric Constant In Ultrathin Granular Metal Films Near The Percolation Threshold, H. Bakkali, E. Blanco, Samuel Lofland, M. Dominguez
College of Science & Mathematics Departmental Research
We report on the electronic and optical properties of ultrathin granular films. We demonstrate that the static dielectric constant increases with thickness in the dielectric regime and diverges at the critical thickness, as predicted by classical percolation theory. However, for thicker samples, the dc conductivity does not obey scaling laws due to the presence of tunneling conduction. In this region the dielectric constant is positive, and the electronic transport is not metallic but can be described by Jonscher's universal power law, even though there is a Drude-like response indicating the presence of free charge carriers. Only for thicker films when …
In Situ Electric-Field Study Of Surface Effects In Domain Engineered Pb(In1/2nb1/2)O3-Pb(Mg1/3nb2/3)O3-Pbtio3 Relaxor Crystals By Grazing Incidence Diffraction, Markys G. Cain, Margo Staruch, Paul Thompson, Christopher Lucas, Didier Wermeille, Yves Kayser, Burkhard Beckhoff, Samuel Lofland, Peter Finkel
In Situ Electric-Field Study Of Surface Effects In Domain Engineered Pb(In1/2nb1/2)O3-Pb(Mg1/3nb2/3)O3-Pbtio3 Relaxor Crystals By Grazing Incidence Diffraction, Markys G. Cain, Margo Staruch, Paul Thompson, Christopher Lucas, Didier Wermeille, Yves Kayser, Burkhard Beckhoff, Samuel Lofland, Peter Finkel
College of Science & Mathematics Departmental Research
In this work, we present a grazing incidence X-ray diffraction study of the surface of a 0.24Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) [011] poled rhombohedral single crystal. The near surface microstructure (the top several tens to hundreds of unit cells) was measured in situ under an applied electric field. The strains calculated from the change in lattice parameters have been compared to the macroscopic strain measured with a strain gauge affixed to the sample surface. The depth dependence of the electrostrain at the crystal surface was investigated as a function of temperature. The analysis revealed hidden sweet spots featuring unusually high strains that were …
Protein And Polysaccharide-Based Fiber Materials Generated From Ionic Liquids: A Review., Christopher R Gough, Ashley Rivera-Galletti, Darrel A Cowan, David Salas-De La Cruz, Xiao Hu
Protein And Polysaccharide-Based Fiber Materials Generated From Ionic Liquids: A Review., Christopher R Gough, Ashley Rivera-Galletti, Darrel A Cowan, David Salas-De La Cruz, Xiao Hu
College of Science & Mathematics Departmental Research
Natural biomacromolecules such as structural proteins and polysaccharides are composed of the basic building blocks of life: amino acids and carbohydrates. Understanding their molecular structure, self-assembly and interaction in solvents such as ionic liquids (ILs) is critical for unleashing a flora of new materials, revolutionizing the way we fabricate multi-structural and multi-functional systems with tunable physicochemical properties. Ionic liquids are superior to organic solvents because they do not produce unwanted by-products and are considered green substitutes because of their reusability. In addition, they will significantly improve the miscibility of biopolymers with other materials while maintaining the mechanical properties of the …