jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Amy J. Brandt
Source: Scholar Commons (University of South Carolina) (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Bimetallic Systems for Heterogeneous Catalysis and Tuning Electronic Properties of Functional Materials Throughout the past few decades, advancements have been made in altering monometallic materials through addition of a second metal to create a bimetallic material that displays enhanced properties over its monometallic components and optimized attributes toward the intended application. However, a lack of fundamental understanding of the interactions between the two metals and between the metals and their environment can hinder the process of designing enhanced functional materials with desirable properties. In this work, careful analysis of model catalysts and metal-organic frameworks (MOFs) is performed in ultrahigh vacuum, and evaluation of the catalytic activity of the catalysts and electronic properties of the MOFs establishes a relationship between the interactions of the bimetallic materials and their properties. Platinumrhenium surfaces on diverse supports including TiO2, HOPG, and Pt(111) are investigated for the effect of differences in their composition and morphology on their catalytic activity for the water-gas shift (WGS) reaction, as well as their potential for oxidation. Catalysts consisting of Pt with subsurface Re are found to have enhanced activity over Pt alone regardless of the support being used. However, clusters on the TiO2 support have greater activity overall, indicating the oxide support plays a role in facilitating the reaction. The oxidation of Re is enhanced in the presence of Pt on all supports, and is attributed to greater dispersion when Re is intermixed with Pt. The electronic properties of copper-containing MOFs are studied by transmetallating a second metal into the framework, including cobalt, rhodium, iron, manganese, ruthenium, or nickel to form a bimetallic MOF. Alternate secondary building units (SBUs) of monomeric M-HHTP, dimeric M2-BTC and pentameric M5-NIP metal centers are used with the monometallic and bimetallic MOFs to fully investigate the parameters that influence their electronic properties. The bimetallic CuCo-BTC and CuRh-BTC MOFs exhibit more density of states (DOS) near the Fermi edge (EF) than the monometallic Cu-BTC MOF, demonstrating the influence of incorporating a second metal into the framework. However both the monometallic and bimetallic MOFs using the HHTP ligand all have greater DOS near EF than the Cu-BTC MOF; and the Cu-NIP and CuRh-NIP also show enhanced DOS near EF, suggesting the ligand plays an influential role in determining the DOS as well. Thin MOF films of Cu-BTC grown via dip-coating demonstrated successful transmetallation with Co to produce bimetallic CuCo-BTC films with controllable Co concentration based on immersion time and temperature. Films maintained a uniform coverage of the substrate and crystalline structure upon initial growth and after undergoing transmetallation. Bimetallic strip ; Catalysis ; Nanotechnology ; Materials science ; Computer science ; Chemistry Catalytic Processes in Materials Science
Authors: Camelia Drăghici | Viktoria Mikhalevich | Gesine Gunkel-Gabrol | Justyna Kowal | Wolfgang Meier | Cornelia G. Palivan
Source: edoc (University of Basel) (article, 2019-01-01)
Field: Materials Science — Biomaterials

Functional Surfaces: Bio-Hybrid Membranes for Biosensing Combining natural enzymes with synthetic membranes on solid support enables creation of functional surfaces able to serve for efficient biosensing. Enzymes (laccase and tyrosinase) integrated on soft copolymer mono- and bilayer membranes preserve their activity and specifically detect the presence of phenols. The straightforward approach to create these bio-hybrid membranes allows changing the enzyme type and thus producing functional surfaces for sensitive detection of desired molecules. Biosensor ; Membrane ; Nanotechnology ; Chemistry ; Computer science ; Materials science ; Biochemistry Diatoms and Algae Research
Authors: Faezeh Sabri
Source: PolyPublie (École Polytechnique de Montréal) (article, 2019-07-01)
Field: Materials Science — Materials Chemistry

Novel Reversible “Sticky” Particles Grafted With Gelling Polysaccharides to Control the Stability of Pickering Emulsions In this article, we demonstrate that submicrometer particles with surface-grafted sodium alginate (SA) display enhanced and reversible aggregation/disaggregation properties in aqueous solution.300 nm silica particles were first functionalized with an aminosilane coupling agent, followed by the grafting of pH-sensitive SA, as confirmed by zeta potential, XPS and FTIR analyses.The SAmodified particles show enhanced aggregation properties at acidic pH compared to unmodified silica, with a 10 times increase in average aggregate diameter.The process is reversible, as the aggregates can be broken and dispersed again when the pH is increased back to 7.0.As a result, the sedimentation rate of SA-modified particles at pH 3.0 is both significantly faster and complete compared to the unmodified particles.This enhanced aggregation is most likely due to the formation of intermolecular hydrogen bonds between neighboring SA-modified particles.This work illustrates how Pickering emulsion ; Destabilisation ; Chemistry ; Humanities ; Emulsion ; Art ; Organic chemistry Pickering emulsions and particle stabilization ; Proteins in Food Systems ; Micro and Nano Robotics
Authors: Osella Silvio | Kiliszek Małgorzata | Ersan Harputlu | Unlu Cumhur G. | Kasım Ocakoğlu | Trzaskowski Bartosz | Kargul Joanna
Source: Figshare (article, 2019-11-21)
Field: Materials Science — Materials Chemistry

Role of Metal Centers in Tuning the Electronic Properties of Graphene-Based Conductive Interfaces Combined theoretical and experimental characterization of self-assembly of pyrene derivatives on graphene monolayer for efficient charge transfer process. Graphene ; Materials science ; Electrical conductor ; Nanotechnology ; Metal ; Composite material ; Metallurgy Graphene research and applications ; Conducting polymers and applications
Authors: Kavita Attri | Manish Yadav | Sonika Shrivastav
Source: Journal of Drug Delivery and Therapeutics (article, 2019-05-22)
Field: Materials Science — Biomaterials

Nanoparticles: A Novel Approach for Targeted Delivery of Medicines The utilization of nanotechnology in medicine and all the more explicitly tranquilize conveyance is resolved to spread quickly.Right now numerous substances are under scrutiny for medication conveyance and all the more explicitly for disease treatment Strangely pharmaceutical sciences are utilizing nanoparticles to lessen lethality and reactions of medications and up to as of late did not understand that bearer frameworks themselves may force dangers to the patient.The sort of risks that are presented by utilizing nanoparticles for medication conveyance are past that presented by customary perils forced by synthetic concoctions in established conveyance frameworks. For nanoparticles the learning on molecule danger as got in inward breath poisonous quality tells the way the best way to examine the potential risks of nanoparticles. The toxicology of particulate issue contrasts from toxicology of substances as the making chemical(s) could conceivably be dissolvable in natural frameworks, therefore impacting extraordinarily the potential presentation of different inside organs. This may differ from a fairly high neighborhood introduction in the lungs and a low or neglectable presentation for other organ frameworks after inward breath. Be that as it may, ingested species may likewise impact the potential harmfulness of the breathed in particles. For nanoparticles the circumstance is distinctive as their size opens the potential for intersection the different organic boundaries inside the body. From a positive perspective, particularly the possibility to cross the blood cerebrum hindrance may open new ways for medication conveyance into the mind. Likewise, the nanosize additionally takes into consideration access into the cell and different cell compartments including the core. A large number of substances are right now under scrutiny for the arrangement of nanoparticles for medication conveyance, differing from organic substances like egg whites, gelatin and phospholipids for liposomes, and more substances of a concoction nature like different polymers and strong metal containing nanoparticles. This paper gives a diagram on a portion of the right now utilized frameworks for medication conveyance. Nanoparticle ; Nanotechnology ; Business ; Chemistry ; Materials science Nanoparticle-Based Drug Delivery ; Advanced Drug Delivery Systems ; Drug Solubulity and Delivery Systems
Authors: Liqiang Yang | Wei You | Zhou, Huaxing
Source: UNC Libraries (article, 2019-12-17)
Field: Materials Science — Polymers and Plastics

Rational design of high performance conjugated polymers for organic solar cells The research on the polymer-based solar cells (PSCs) has attracted an increasing amount of attention in recent years because PSCs pose potential advantages over mainstream inorganic-based solar cells, such as significantly reduced material/fabrication costs, flexible substrates, and light weight of finished solar cells. The research community has made great progress in the field of bulk heterojunction (BHJ) polymer solar cells since its inception in 1995. The power conversion efficiency (PCE), a key parameter to assess the performance of solar cells, has increased from 1% in the 1990s to over 8% just recently. These great advances are mainly fueled by the development of conjugated polymers used as the electron-donating materials in BHJ solar cells. In this Perspective, we first briefly review the progress on the design of conjugated polymers for polymer solar cells in the past 16 years. Since a conjugated polymer can be arbitrarily divided into three constituting componentsthe conjugated backbone, the side chains, and the substituentswe then focus on the rational design of conjugated polymers by separately discussing the influence of each component on the physical and photovoltaic (PV) properties of these polymers. Special attention is paid to the design of donor− acceptor type low-band-gap polymers because this approach is prevailing in the literature with its unique features. In doing so, we strive to extract useful rules for the rational design of conjugated polymers with predictable properties. We conclude by proposing future research opportunities to achieve even higher PCEs for PSCs. Conjugated system ; Materials science ; Organic solar cell ; Rational design ; Polymer ; Nanotechnology ; Composite material Conducting polymers and applications ; Organic Electronics and Photovoltaics
Authors: Atheer M. Mkhaiber
Source: Iraqi Journal of Physics (article, 2019-01-05)
Field: Chemistry — Organic Chemistry

The effect of heat treatment on the optical properties of organic semiconductor (NiPc/C60) thin films Thin films of the blended solution of (NiPc/C60) on glass substrates were prepared by spin-coated method for three different ratios (100/1, 100/10 and 100/100). The effects of annealing temperature and C60 concentration on the optical properties of the samples were studied using the UV-Vis absorption spectroscopy and FTIR spectra. The optical absorption spectrum consists of two main bands, Q and B band, with maxima at about (602-632) nm and (700-730) nm for Q1 and Q2 respectively, and (340-375) nm for B band. The optical energy gap were determined from optical absorption spectra, The variation of optical energy gap with annealing temperature was nonsystematic and this may be due to the improvement in crystal structure for thin films. While the energy gap decreased by increasing the concentration of C60 approaches from the energy gap of this compound. Materials science ; Band gap ; Annealing (glass) ; Thin film ; Absorption spectroscopy ; Semiconductor ; Fourier transform infrared spectroscopy ; Analytical Chemistry (journal) ; Spectroscopy ; Absorption (acoustics) ; Optoelectronics ; Optics ; Nanotechnology ; Chemistry ; Organic chemistry Fullerene Chemistry and Applications ; Organic Electronics and Photovoltaics ; Molecular Junctions and Nanostructures
Authors: Dylan L. Riggs
Source: eScholarship (California Digital Library) (article, 2019-01-01)
Field: Chemistry — Spectroscopy

Shining the Light on Aging and Isomers Using Photodissociation and Radical Chemistry Biological aging is a complex and nuanced chemical process that proceeds along numerous routes at the molecular level. Spontaneous deamidation of asparagine and isomerization of aspartic acid are among the most prevalent age-related chemical modifications and are associated with a growing list of human diseases. Although both degradation pathways are common throughout the body, they are often unnoticed because the resulting chemical modification is relatively minor and is exceptionally difficult to detect. Structural characterization is further complicated because both deamidation and isomerization produce four isomers of aspartic acid (L-Asp, D-Asp, L-isoAsp, and D-isoAsp). To better understand the aging process, we utilized radical directed dissociation (RDD) in conjunction with mass spectrometry to identify and quantify the products of deamidation and isomerization. We began by outlining intrinsic factors that govern the deamidation rate, and external factors that influence product outcomes to develop models of peptide and protein aging. Subsequent studies revealed the specific structural and functional perturbations associated with the unnatural isomers present in aged proteins. To further expand our isomer detection capabilities, we applied our radical based fragmentation method to the glutamine deamidation, which exhibits several parallels to asparagine deamidation, but has remained largely uncharacterized. Importantly, we demonstrate that radical chemistry generated diagnostic and informative fragment ions for both glutamic acid and isoglutamic acid. We apply this technique in a manner that is amenable to shotgun proteomics and reveal several key differences between the two aging processes. Finally, we tailor our radical based analytical methodology toward the analysis of isomeric glycans. After successfully discriminating a comprehensive family of isomeric glycans with RDD, we demonstrate similar capabilities with 213 nm ultraviolet photodissociation, and outline how such a versatile approach may unify the closely related fields of glycomics and proteomics. Deamidation ; Chemistry ; Asparagine ; Isomerization ; Aspartic acid ; Radical ; Structural isomer ; Biochemistry ; Stereochemistry ; Amino acid ; Catalysis ; Enzyme Advanced Proteomics Techniques and Applications ; Molecular Biology Techniques and Applications ; Protein Hydrolysis and Bioactive Peptides
Authors: Baillie A. DeHaven
Source: Scholar Commons (University of South Carolina) (article, 2019-01-01)
Field: Materials Science — Biomaterials

Emergent Properties and Applications of Self- Assembled Benzophenone-Containing Materials Supramolecular assembly of benzophenone through urea hydrogen bonding interactions facilitates the formation of remarkably persistent triplet radical pairs upon UV-irradiation at room temperature, whereas no radicals are observed in solution. The generation of organic radicals is correlated to the microenvironment around the benzophenone carbonyl, the types of proximal hydrogens, and the rigid supramolecular network. High-Field EPR and variable temperature X-band EPR accompanied by simulations suggest a resonance stabilized radical pair through hydrogen abstraction. Previous work has shown that UV-irradiation of self-assembled benzophenone bis-urea host results in low quantities of radical pairs that can be used to enhance NMR signals by a factor of 4 for both the host and the encapsulated guest using a dynamic nuclear polarization (DNP) technique. This result suggests that even low levels of endogenous radicals can facilitate the study of host-guest relationships in the solid-state.2 Additionally, the photochemical formation of reactive oxygen species (ROS) by the host was examined, which was found to generate both superoxide and singlet oxygen in similar quantities. The host was then applied as a nanoreactor to mediate photooxidations of 1-methyl-1-cyclohexene while suspended in solution and as a solvent free host:guest complex. Benzophenone ; Nanotechnology ; Materials science ; Polymer chemistry Supramolecular Self-Assembly in Materials ; Porphyrin and Phthalocyanine Chemistry ; Synthesis and properties of polymers
Authors: Kim, Jason Sung
Source: Carolina Digital Repository (University of North Carolina at Chapel Hill) (article, 2019-08-13)
Field: Materials Science — Biomaterials

Innovative biomedical applications using hybrid nanoparticles Nanoparticle and metal-chelate technologies can be combined to create innovative hybrid materials with versatile functions for research and clinical purposes. This dissertation addresses the novel use of hybrid inorganic/organic nanoparticles in biomedical applications, including early detection of autoimmune disease and cancer as well as purification of therapeutic proteins. In an in vivo animal model of rheumatoid arthritis (RA), fluorescent nanoparticles coated with a magnetic resonance imaging (MRI) contrast enhancing metalchelate are used for cell specific trafficking of monocytes, which correlate with disease activity. Metal-chelate derivatized magnetic nanoparticles isolate tagged proteins, potential cancer therapeutics, from impurities generated from bacterial and mammalian cell expression systems. The novel applications of hybrid magnetic nanoparticles pursued in this dissertation have the ability to translate into new and more sensitive strategies to treat patients with chronic disease. Nanotechnology ; Computer science ; Materials science Nanoparticle-Based Drug Delivery ; Nanotechnology research and applications ; Rheumatoid Arthritis Research and Therapies
Authors: Gurshagan Kandhola
Source: Journal of the Arkansas Academy of Science (article, 2019-01-01)
Field: Materials Science — Biomaterials

Optimized Production and Evaluation of Cellulose Nanocrystals Derived from Pre-Extracted Kraft Pulp of Different Wood Species Production of nanocellulose from a variety of naturally abundant, locally available and industrially significant wood species provides an opportunity for diversifying the portfolio of traditional pulp and paper industries. The U.S. has a prolific forest products industry with a well-established infrastructure that could be utilized for optimized and customized production of cellulose nanomaterials. However, to achieve that, it is important to a) understand how biorefining strategies for complete fractionation of biomass affect the downstream processing of pulp into nanocellulose, b) maximize the yields of cellulose nanocrystals and nanofibers (CNCs and CNFs) from pretreated raw materials, and c) evaluate if the yields and properties of CNCs vary based on the wood species used as the starting material. In the first objective, effect of pre-extraction prior to kraft pulping on the yields and properties of CNCs and CNFs was evaluated, using loblolly pine as a model substrate. Differences between cellulose nanomaterials obtained from pre-extracted vs non-extracted pulp were found with respect to their yield, crystallinity index, surface charge, particle size and thermal stability. Overall, kraft pulp purity was found to be a significant factor impacting the quality and quantity of nanocellulosic materials. In the second objective, strong acid strong acid hydrolysis-based production of CNCs and CNFs from pre-extracted and fully bleached loblolly pinewood kraft pulp was optimized using response surface methodology. Conditions, with respect to acid concentration, temperature, duration and pulp particle size, that maximized CNC and CNF yields were identified. In the third objective, four wood species were evaluated for CNC production using strong acid hydrolysis conditions that were previously optimized for pinewood. Differences in the yield of CNCs among the four species was found to be strongly correlated with pulp purity. Differences in the morphological, thermal and mechanical properties were also observed, highlighting the tuning potential of CNCs based on raw material selection. This research will advance the production and targeted application of nanocellulose derived from wood biomass. Kraft process ; Pulp and paper industry ; Cellulose ; Pulp (tooth) ; Kraft paper ; Chemistry ; Paper production ; Materials science ; Organic chemistry ; Engineering Advanced Cellulose Research Studies ; Lignin and Wood Chemistry
Authors: Kelly K. McGrath
Source: Digital Scholarship - UNLV (University of Nevada Reno) (article, 2019-05-29)
Field: Chemistry — Organic Chemistry

Synthesis and characterization of novel asymmetrically substituted bisphenazines and their self assembling properties The self-assembly of pi-conjugated materials into one-dimensional (1-D) nanostructures via intermolecular pi-electron overlap is of particular interest for optoelectronic device miniaturization. There have been a number of pi-conjugated organic semiconductors reported with the ability to self-assemble to produce nanofibers, nanobelts, and nanotubes. However, the majority of these molecules are electron-rich (p-type) and thus the demand for electron-deficient (n-type) semiconductors is high since the availability of useful n-type semiconductors is limited; The design strategy and synthetic routes for novel n-type organic semiconductors based on bisphenazine are reported. The thermal, optical, and electrochemical properties studied by DSC, UV-visible and fluorescence spectroscopy, and cyclic voltammetry (CV) are presented. Electronic properties from theoretical calculations are also compared with the experimental results. The assembling properties, organogelation and 1-D assembly, of these new n-type molecules will be discussed with extensive investigations by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-Transform infrared (FT-IR) spectroscopy. Characterization (materials science) ; Chemistry ; Nanotechnology ; Computer science ; Materials science Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and properties of polymers ; Synthesis and Biological Evaluation
Authors: Luc Jacobs | Cédric Barroo | Bernhard von Boehn | Matthias Homann | R. Imbihl | Thierry Visart de Bocarmé
Source: Microscopy and Microanalysis (article, 2019-08-01)
Field: Materials Science — Materials Chemistry

Understanding Fundamental Processes on Au-Ag Catalysts during Oxidation Reactions: a Correlative Microscopy Approach info:eu-repo/semantics/nonPublished Correlative ; Catalysis ; Materials science ; Microscopy ; Chemical engineering ; Nanotechnology ; Chemistry ; Organic chemistry ; Optics ; Physics ; Engineering ; Philosophy Catalytic Processes in Materials Science ; Nanocluster Synthesis and Applications ; Nanoporous metals and alloys