jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Matti Leskinen
Source: Työväentutkimus Vuosikirja (article, 2018-01-01)
Field: Materials Science — Biomaterials

Novel cellulose particles by regeneration from homogeneous solution The theme of the thesis has been the preparation of cellulose particles from homogeneous ionic liquid solutions. The work approaches this topic from the materials chemistry perspective and focuses on physical properties of the obtained materials and the methodological details of their preparation.\n\nNovel cellulose macro- and microparticles have been prepared from two cellulose solvents systems, [DBNH][OAc]/DMSO and [P4441][OAc]/GVL. The two types of particles and their preparation methods are very different and distinct. The large beads are prepared using remarkably simple hands-on method, while the small particles are prepared by exploiting a thermally triggered gelation of cellulose. Both particles are scientifically interesting and observations made during their preparation provide insight to the field of cellulose materials chemistry. Special attention has been given to exploring their potential applications outside the laboratory in the commercial and industrial sectors.\n\nThe laboratory work examines the experimental parameters of the cellulose particle production methods in detail. The particle preparation methods are very simple in practice. Emphasis has been given to describing the observed novel phenomena and fine-tuning the processes for efficiency. The procured cellulose particles have been analysed using a variety of methods including optical microscopy, SEM, XRD, WAXS, CP-MAS, VSM and H-NMR. Cellulose ; Homogeneous ; Regeneration (biology) ; Chemistry ; Polymer science ; Chemical engineering ; Mathematics ; Engineering ; Biology ; Combinatorics ; Cell biology Advanced Cellulose Research Studies
Authors: Zhen Zhang
Source: UNM’s Digital Repository (University of New Mexico) (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

SYNTHESIS, CHARACTERIZATION AND APPLICATION OF STRUCTURALLY DIVERSE POLY(CHALCOGENYLENE VINYLENE)S Conjugated polymers have found widespread applications in flexible and printable electronic devices, among which poly(thienylene vinylene) (PTV) displays outstanding optoelectronic properties and promising applications. However, further studies of its structure-property-function relationship have been greatly impeded mainly due to the synthetic difficulty of generating new structures beyond its rudimentary form. To further investigate this class of material, I have developed a facile methodology for the preparation of structurally diverse poly(chalcogenylene vinylene)s (PCVs) through a combination of acyclic diene metathesis (ADMET) polymerization and post-polymerization modification techniques. Specifically, a series of halogenated and cross-conjugated PCVs have been designed and synthesized, followed by complete characterizations. It was found the physical and optoelectronic properties of the obtained polymers can be fine-tuned through introducing halogen atoms and specific conjugated side chains. Interestingly, the PTVs with strong electron withdrawing cyano groups were found to be emissive, which is rarely observed in this class of materials. The newly prepared polymers combining with PCBM (electron acceptor) were eventually fabricated into solar cell devices. Power conversion efficiency of ca. 1.6%, 2-fold higher than the parent PTV, was achieved, resulting from the optimized energy levels, crystallinity and broadened absorption via chemical modifications. Our methodologies provide a facile tool to effectively diversify PTV’s structures and then systematically study their structure-property-function relationships, which enhanced our basic understanding on this type of materials and will potentially lead to new materials for advanced electronic applications. The other part of the dissertation is about the preparation, photophysical studies and application of a conjugated Pt-containing small molecule. The incorporation of Pt atom into this molecule is supposed to increase the triplet exciton generation after radiation due to the heavy atom effect, offering us the opportunity to investigate the formation and transport of the triplet excitons and eventually capture them for solar cells. This acceptor is composed of our previously designed Pt-containing electron-rich unit in the middle and strong electron-deficient units on both sides. It was found that this acceptor-donor-acceptor Pt-containing compound possesses broad absorption from 300 to 1000 nm, good crystallinity and low LUMO energy level, which are prerequisite for a good acceptor material of organic solar cells. The device performance of the Pt-containing compound is currently under investigation. Characterization (materials science) ; Materials science ; Polymer science ; Chemistry ; Polymer chemistry ; Nanotechnology Chemistry and Stereochemistry Studies
Authors: Martina Di Francesco | Rosita Primavera | Davide Romanelli | Roberto Palomba | Rui C. Pereira (4925011) | Tiziano Catelani | Christian Celia | Luisa Di Marzio | Massimo Fresta | Daniele Di Mascolo | Paolo Decuzzi
Source: Figshare (preprint, 2018-03-09)
Field: Materials Science — Biomaterials

Hierarchical\nMicroplates as Drug Depots with Controlled Geometry, Rigidity, and\nTherapeutic Efficacy A variety\nof microparticles have been proposed for the sustained and localized\ndelivery of drugs with the objective of increasing therapeutic indexes\nby circumventing filtering organs and biological barriers. Yet, the\ngeometrical, mechanical, and therapeutic properties of such microparticles\ncannot be simultaneously and independently tailored during the fabrication\nprocess to optimize their performance. In this work, a top-down approach\nis employed to realize micron-sized polymeric particles, called microplates\n(μPLs), for the sustained release of therapeutic agents. μPLs\nare square hydrogel particles, with an edge length of 20 μm\nand a height of 5 μm, made out of poly­(lactic-&lt;i&gt;co&lt;/i&gt;-glycolic acid) (PLGA). During the synthesis process, the μPL\nYoung’s modulus can be varied from 0.6 to 5 MPa by changing\nthe PLGA amounts from 1 to 7.5 mg, without affecting the μPL\ngeometry while matching the properties of the surrounding tissue.\nWithin the porous μPL matrix, different classes of therapeutic\npayloads can be incorporated including molecular agents, such as anti-inflammatory\ndexamethasone (DEX), and nanoparticles containing imaging and therapeutic\nmolecules themselves, thus originating a truly hierarchical platform.\nAs a proof of principle, μPLs are loaded with free DEX and 200\nnm spherical polymeric nanoparticles, carrying DEX molecules (DEX–SPNs).\nElectron and fluorescent confocal microscopy analyses document the\nuniform distribution and stability of molecular and nanoagents within\nthe μPL matrix. This multiscale, hierarchical microparticle\nreleases DEX for at least 10 days. The inclusion of DEX–SPNs\nserves to minimize the initial burst release and modulate the diffusion\nof DEX molecules out of the μPL matrix. The biopharmacological\nand therapeutic properties together with the fine tuning of geometry\nand mechanical stiffness make μPLs a unique polymeric depot\nfor the potential treatment of cancer, cardiovascular, and chronic,\ninflammatory diseases. Nanoparticle ; Drug delivery ; Materials science ; PLGA ; Biomedical engineering ; Nanotechnology ; Biophysics ; Medicine Nanoparticle-Based Drug Delivery ; Advanced Drug Delivery Systems ; Advancements in Transdermal Drug Delivery
Authors: Ruža Frkanec | Karmen Radošević | Adela Štimac | Lucija Horvat | Leo Frkanec
Source: Proceedings of the 35th European Peptide Symposium (article, 2018-01-01)
Field: Materials Science — Biomaterials

Development of new supramolecular nanostructuredmaterials based on peptide hydrogelator Ac-L-Phe-L-Phe-L-Ala-NH2 with embedded liposomes for potential biomedical application In recent years design and synthesis of self-assembled nanomaterialswith diversified structuresand functionalities via fine tuning of supramolecular building blocks increased rapidly.[1] Self-assembling peptides have been widely recognized as nanomaterials with high potential for an extensive range of biomedical applications from drug delivery to tissue enginering, owing to their hydrophilic character and biocompatibility.[2,3] Short peptide hydrogels made of two or three amino acids are of particular interest because they are cost effective and simple to prepare. It was previously shown that the newly developed self-assembling tripeptide hydrogel Ac-L-Phe-L-Phe-L-Ala-NH 2 (Ac-F-F-A-NH 2 ) is effective in enhancing cell proliferation and has potential for use in tissue engineering approaches. Tripeptide ; Self-healing hydrogels ; Supramolecular chemistry ; Peptide ; Biocompatibility ; Nanomaterials ; Nanotechnology ; Drug delivery ; Combinatorial chemistry ; Chemistry ; Liposome ; Tissue engineering ; Amino acid ; Materials science ; Biochemistry ; Biomedical engineering ; Organic chemistry ; Molecule ; Engineering Supramolecular Self-Assembly in Materials ; Chemical Synthesis and Analysis ; Glycosylation and Glycoproteins Research
Authors: Jake Yeston
Source: Science (article, 2018-08-09)
Field: Chemistry — Organic Chemistry

A rapid screen for complex reactants Organic Chemistry Chemists engaged in reaction discovery tend to report outcomes involving a few, relatively simple reactants. It remains a major challenge to fine-tune reported conditions when the reactants become more structurally complex, as often happens in pharmaceutical research. Lin et al. developed a protocol for rapidly screening different catalytic conditions for C–N coupling across a wide range of complex substrates. The product detection scheme relies on mass spectrometry of nanomole-scale reaction mixtures without any need for intervening chromatography. Science , this issue p. [eaar6236][1] [1]: /lookup/doi/10.1126/science.aar6236 Chemistry ; Computer science Chemical synthesis and alkaloids ; Analytical Chemistry and Chromatography ; Chemical Synthesis and Analysis
Authors: Srimanta Pakhira | José L. Mendoza-Cortés
Source: ChemRxiv (preprint, 2018-06-28)
Field: Materials Science — Materials Chemistry

First Row Transition Metals Intercalation of Covalent-Organic Frameworks: A Promising Route to Tune the Material Structure and Electronic Properties Covalent organic frameworks (COFs) have emerged as an important class of nano-porous crystalline materials with many potential applications. They are intriguing platforms for the design of porous skeletons with special functionality at the molecular level. A new form of nanoporous material, transition metal intercalated COFs is proposed and its electronic properties are revealed. Using first-principles dispersion-corrected hybrid density functional theory (DFT-D), we have designed 31 new COF materials in-silico by intercalating all of the first row transition metals (TMs) with boroxine-linked and triazine-linked COFs. This is a significant addition considering that only 187 experimentally COFs structures has been reported and characterized so far. We have investigated their frameworks properties as well as material properties. Specifically, we predict that COF's band gap and density of states (DOSs) can be fine tuned by intercalating first row transition metal atoms (TM: Sc - Zn). The present DFT-D calculations showed that the d-subshell electron density of the TMs plays an important role in determining the material properties of the COFs. The implications of controllable electronic structure and properties of intercalated COF materials for future device applications are discussed. Thus intercalated-COFs provide a new strategy to create semi-conducting and conducting materials within a rigid porous network in a highly controlled and predictable manner. This work opens up new avenues for the efficient production of TM-intercalated materials with promising future applications in nanoporous material science, electronics and chemical sensors. Materials science ; Intercalation (chemistry) ; Nanoporous ; Covalent bond ; Nanotechnology ; Density functional theory ; Transition metal ; Electronic structure ; Chemistry ; Computational chemistry ; Organic chemistry Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Mesoporous Materials and Catalysis
Authors: Zachary L. Palchak
Source: eScholarship (California Digital Library) (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Advancing Methods to Synthesize Nitrogen-Containing Small Molecules for Catalysis and as Potential Therapeutics Analysis of the current top grossing pharmaceuticals finds that a vast number of them contain amines. As a result, the development of methodologies for the formation of amine-containing compounds is of high value and great importance. With the ability to treat: cancer, HIV, malaria, diabetes, and depression, as well as other ailments, increased efforts have been made to optimize the production of these compounds to increase yield while decreasing the environmental impact. This work is ongoing, and is a culmination of the fields of organic synthesis, catalysis, green chemistry, and biochemistry. The work in the Larsen group revolves largely around the use of copper-based catalysis to access hindered amine scaffolds through single-step, multicomponent reactions. Further functionalization of these compounds allows for the synthesis of previously unknown, biologically active, Î±-amino triazoles. Preparation and analysis of electronically diverse pyridyl triazoles allows for the development of new complexes with platinum and palladium. These pyridyl triazole palladiumcomplexes are highly reactive under mild aerobic conditions when used in Suzuki-Miyaura cross-coupling reactions. Pyridyl pyrazoles are another class of compounds that show promise in the field of catalysis. Utilization of electronically diverse ligands allows for fine-tuning of the resulting complex for both classes of ligands. With further investigation, this may allow for the discovery of new reactivity in organic transformations. Chemistry ; Catalysis ; Combinatorial chemistry ; Amine gas treating ; Palladium ; Organic synthesis ; Organic chemistry ; Reactivity (psychology) ; Yield (engineering) ; Materials science Catalytic Cross-Coupling Reactions ; Click Chemistry and Applications ; Catalytic C–H Functionalization Methods
Authors: Lucas Schreyer
Source: Kölner Universitäts PublikationsServer (Universität zu Köln) (article, 2018-07-16)
Field: Chemistry — Organic Chemistry

IDPi Catalysis - The Hosomi–Sakurai Allylation and a Mukaiyama Aldol Reaction with Enolsilanes of Acetaldehyde The following work describes the development and application of imidodiphosphorimidates (IDPi) in enantioselective organic Lewis acid catalysis. This new class of catalysts was generated by the replacement of the O-atoms of the Brønsted acidic and Lewis basic sites of the core of previously developed imidodophosphate (IDP) catalysts by NTf groups (the "Yagupolskii principle"). IDPi are of sufficiently enhanced Brønsted acidity and weakened Lewis basicity for the application in "silylium" Lewis acid catalysed transformations. Therefore, while IDP were catalytically inactive, silylated IDPi activated aldehydes for the addition of even weakly nucleophilic silanes. One long standing problem in this regard has been the enantioselective addition of allyltrimethylsilane to aldehydes, the "Hosomi-Sakurai" allylation. This transformation was beyond reach with the previously developed organic Lewis acid disulfonimide (DSI) precatalysts. By fine-tuning of the catalyst structure, a highly enantioselective allylation of a variety of aromatic and even simple aliphatic aldehydes was enabled, at catalysts loadings as low as 0.05mol%. The products obtained by this method, homoallylic alcohols, are frequently applied as intermediates for the synthesis of (protected) acetaldehyde aldols within 2 more steps, by O-protection and olefin oxidation. With our powerful new catalysts, we realized a single step enantioselective method to synthesize these aldols in a Mukaiyama aldol reaction with simple enolsilanes of acetaldehyde. Various functionalized and unfunctionalized aromatic and aliphatic aldehydes were readily transformed into the corresponding single aldolisation products in high yields and enantiomeric ratios, at short reaction times (5 min to 10 h) with low catalyst loadings (0.5-2.0 mol%). The method described in this thesis have solved long-standing problems in organic synthesis. Inexpensive, non-toxic allyltrimethylsilane can now be used for highly enantioselective allylations of aldehydes. While other strong Lewis acids such as triflimide catalyse the oligomerisation of enolsilanes of acetaldehyde, our IDPi successfully distinguishes substrate and product aldehydes, enabling highly enantioselective single step syntheses of aldols which previously were accessible in only sequences of several transformations. Aldol reaction ; Acetaldehyde ; Catalysis ; Chemistry ; Organic chemistry ; Ethanol Synthetic Organic Chemistry Methods ; Chemical Synthesis and Reactions ; Asymmetric Synthesis and Catalysis
Authors: Pavle V. Radovanovic
Source: 2018-Sustainable Industrial Processing Summit (article, 2018-07-23)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Plasmonic Semiconductor Nanocrystals as Multifunctional Materials Synthesis, properties, and applications of plasmonic nanostructures with tunable localized surface plasmon resonance (LSPR) have been a subject of intense investigation over the past decade. Unlike typical metal nanoparticles, colloidal plasmonic semiconductor nanocrystals have LSPR frequencies tunable in the near- to mid-infrared region, which can potentially allow for their applications in terahertz imaging, heat-responsive devices and surface-enhanced infrared spectroscopic techniques [1]. Furthermore, the ability to control type and concentration of charge carriers, as well as their activation, trapping, and scattering via nanocrystal composition and/or surface chemistry allows for fine tuning of the energy, band width, and quality factor of LSPR in semiconductor nanocrystals. Besides expanding the LSPR range, semiconductor nanocrystals bring about numerous other opportunities related to single-phase plasmon-exciton interactions. However, non-resonant nature of the LSPR and exciton in semiconductor nanocrystals has been a major obstacle toward realizing such opportunities. This talk will first introduce the general properties of colloidal plasmonic semiconductor nanocrystals and compare them with those of noble metal nanoparticles. Then, various ways of generating and controlling the type, concentration, and mobility of charge carriers in these materials [2] will be reviewed. The second part of the talk will focus on the results of our recent work on structure and composition dependent plasmonic properties of transparent metal oxide nanocrystals [3,4], and particularly on generating robust electron polarization in degenerately-doped In2O3 nanocrystals owing to non-resonant magnetic-field-induced plasmon-exciton coupling [5]. Applications of these materials for photocatalysis, solar energy conversion, and new energy-efficient and sustainable electronic and quantum information technologies will also be discussed. The talk will conclude with general outlook, and future research directions. Materials science ; Plasmon ; Surface plasmon resonance ; Nanocrystal ; Semiconductor ; Nanotechnology ; Optoelectronics ; Charge carrier ; Nanoparticle ; Exciton ; Localized surface plasmon ; Surface photovoltage ; Spectroscopy ; Physics Gold and Silver Nanoparticles Synthesis and Applications ; Quantum Dots Synthesis And Properties
Authors: David C. Chatfield | Alexander N. Morozov
Source: Biophysical Journal (article, 2018-02-01)
Field: Chemistry — Inorganic Chemistry

Influence of Conserved Structural Elements of the Proximal Pocket in HEME-Thiolate Enzymes on Oxygen Insertion Reactions Chemistry ; Heme ; Hydroxylation ; Stereochemistry ; Enzyme ; Cysteine ; Ligand (biochemistry) ; Cytochrome ; Cytochrome P450 ; Active site ; Reactivity (psychology) ; Biochemistry ; Receptor Metal-Catalyzed Oxygenation Mechanisms ; Pharmacogenetics and Drug Metabolism ; Microbial metabolism and enzyme function
Authors: Heejun Choi | Ya-Cheng Liao | Luke D. Lavis | Yoon J Young | Jennifer Lippincott‐Schwartz
Source: Biophysical Journal (article, 2018-02-01)
Field: Chemistry — Organic Chemistry

Probing Dynamics of Proteins via Self-Labeling Tags Fluorophore ; Förster resonance energy transfer ; Chemistry ; Fluorescence ; Alexa Fluor ; Protein tag ; Covalent bond ; Rhodamine ; Green fluorescent protein ; Biophysics ; Conjugated system ; Fusion protein ; Biochemistry ; Biology Click Chemistry and Applications ; Advanced Biosensing Techniques and Applications ; Monoclonal and Polyclonal Antibodies Research
Authors: Nicolás Pazos‐Pérez | Ramón A. Álvarez‐Puebla
Source:  (article, 2018-03-15)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Fabrication of continuous and isolated 3D plasmonic micro-structured super-crystals arrays for SERS sensing (Conference Presentation) Metallic nanoparticles are very interesting because of their potential use in microelectronics, optical devices, biomedical and sensing applications. Their individual electromagnetic response is highly dependent on the specific size, shape, and surrounding environment. Nowadays, there are different methods which allow us to fine tune these parameters and thus, the materials properties. On the other hand, surface enhance Raman scattering (SERS) spectroscopy is a powerful ultra-sensitive technique which allows detection down to single molecule levels. However, the production of effective and highly active SERS substrates is mainly based on the generation of hot spots created by plasmonic nanoparticles. Nonetheless, the lack of capability to form reproducible organized structures at large scales is still a very important challenge to solve in order to produce substrates with homogeneous and reproducible SERS intensities over large areas. In this work, we report novel methods to produce arrays of nanoparticles, either as continuous or as isolated super-crystals made with plasmonic nanoparticles.[1] These macro-scale organizations were created via confinement controlled drying and spin coating. SERS studies on the super-crystals shape and size were conducted. Moreover, the produced structures were effectively use for SERS sensing showing very good reproducibility among big areas. This fact, make them perfect candidates as ultrasensitive substrates for SERS due to the controlled formation of hot spots. Which provide high and uniform SERS enhancement over extended areas. [1] Nanoscale. 2016, 8 12702 Plasmon ; Materials science ; Nanotechnology ; Microelectronics ; Plasmonic nanoparticles ; Nanoparticle ; Fabrication ; Nanoscopic scale ; Raman scattering ; Surface-enhanced Raman spectroscopy ; Raman spectroscopy ; Optoelectronics ; Optics Gold and Silver Nanoparticles Synthesis and Applications ; Advanced Nanomaterials in Catalysis ; Laser-Ablation Synthesis of Nanoparticles