jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Amr Ellaithy
Source: VCU Scholars Compass (Virginia Commonwealth University) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Metabotropic Glutamate Receptor 2 Activation: Computational Predictions and Experimental Validation G protein-coupled receptors (GPCRs) are the largest family of signaling proteins in animals and represent the largest family of druggable targets in the human genome. Therefore, it is of no surprise that the molecular mechanisms of GPCR activation and signal transduction have attracted close attention for the past few decades. Several stabilizing interactions within the GPCR transmembrane (TM) domain helices regulate receptor activation. An example is a salt bridge between 2 highly conserved amino acids at the bottom of TM3 and TM6 that has been characterized for a large number of GPCRs. Through structural modeling and molecular dynamics (MD) simulations, we predicted several electrostatic interactions to be involved in metabotropic glutamate receptor 2 (mGlu2R) activation. To experimentally test these predictions, we employed a charge reversal mutagenesis approach to disrupt predicted receptor electrostatic intramolecular interactions as well as intermolecular interactions between the receptor and G proteins. Using two electrode voltage clamp in Xenopus laevis oocytes expressing mutant receptors and G-proteins, we revealed novel electrostatic interactions, mostly located around intracellular loops 2 and 3 of mGlu2R, that are critical for both receptor and G-protein activation. These studies contribute to elucidating the molecular determinants of mGluRs activation and conformational coupling to G-proteins, and can likely be extended to include other classes of GPCRs. Metabotropic glutamate receptor 5 ; Metabotropic glutamate receptor 1 ; Metabotropic glutamate receptor ; Metabotropic receptor ; Metabotropic glutamate receptor 6 ; Metabotropic glutamate receptor 7 ; Metabotropic glutamate receptor 4 ; Metabotropic glutamate receptor 2 ; Metabotropic glutamate receptor 3 ; Computer science ; Glutamate receptor ; Chemistry ; Neuroscience ; Receptor ; Psychology ; Biochemistry Photochromic and Fluorescence Chemistry ; Neuroscience and Neuropharmacology Research ; Photoreceptor and optogenetics research
Authors: Chang-Sheng Wang
Source: theses.fr (ABES) (article, 2018-10-15)
Field: Chemistry — Organic Chemistry

Synthèses de molécules azotés et phosphorés par fonctionnalisations sélectives de liaisons C(sp²)–H et C(sp³)–H Dans la thèse de doctorat, nous avons développé une approche efficace pour la modification rapide d'oxydes d'arylphosphines via la fonctionnalisation de liaisons C-H en position ortho du groupement P=O catalysée par le ruthénium (II) en présence des alcènes. Intéressement, l'ajustement du pH du milieu réactionnel permet de contrôler la sélectivité de la réaction à savoir alkylation or oléfination. La réduction des oxydes de phosphines fonctionnalisées permet la formation d'arylphosphines portant un carboxylate flexible. Dans le second objectif, un couplage C(sp3)–H /N-H oxydatif catalysé par le cuivre a permis l'alkylation d'hétérocycles à partir de (cyclo alcanes abordables. Ce protocole implique la formation de liaisons C (sp3)–N via une voie radicalaire générée par un clivage homolytique du peroxyde de di-tert-butyle et le piégeage du ou des radicaux par des catalyseurs au cuivre. Dans une troisième partie, nous avons utilisé ces processus radicalaires pour la fonctionnalisation le liassions C(sp3)–H benzylique d'oxyde de 2-alkylpyridines. Ces transformations impliquent un processus en cascade : estérification oxydative catalysée par le cuivre suivie d'un transfert d'atome d'oxygène. Enfin, des dérivés tosylés de pyridin-2-ylméthyl ont été obtenus avec des rendements élevés à partir des oxide de 2-alkylpyridines grâce à un réarrangement sigmatropic [3,3] du produit d'addition entre les oxides de 2-alkylpridine avec des chlorures de chlorure de benzènesulfonyles. De plus, les alkylnitrones subissent également ce réarrangement sigmatropique [3,3] pour donner des cétones α-tosylées après hydrolyse. Alkylation ; Organic peroxide ; Chemical reduction Catalytic C–H Functionalization Methods ; Catalytic Cross-Coupling Reactions ; Radical Photochemical Reactions
Authors: Xuefeng Liu | Wei Lü | Xiaoying Zhou | Yang Zhou | Chenglong Zhang | Jiawei Lai | Shaofeng Ge | Chandra Sekhar M | Shuang Jia | Kai Chang | Dong Sun
Source: 2D Materials (preprint, 2018-01-25)
Field: Materials Science — Materials Chemistry

Dynamical anisotropic response of black phosphorus under magnetic field Black phosphorus (BP) has emerged as a promising material candidate for next generation electronic and optoelectronic devices due to its high mobility, tunable band gap and highly anisotropic properties. In this work, polarization resolved ultrafast mid-infrared transient reflection spectroscopy measurements are performed to study the dynamical anisotropic optical properties of BP under magnetic fields up to 9 T. The relaxation dynamics of photoexcited carrier is found to be insensitive to the applied magnetic field due to the broadening of the Landau levels and large effective mass of carriers. While the anisotropic optical response of BP decreases with increasing magnetic field, its enhancement due to the excitation of hot carriers is similar to that without magnetic field. These experimental results can be well interpreted by the magneto-optical conductivity of the Landau levels of BP thin film, based on an effective k*p Hamiltonian and linear response theory. These findings suggest attractive possibilities of multi-dimensional controls of anisotropic response (AR) of BP with light, electric and magnetic field, which further introduces BP to the fantastic magnetic field sensitive applications. Anisotropy ; Magnetic field ; Condensed matter physics ; Optical conductivity ; Effective mass (spring–mass system) ; Excitation ; Black phosphorus ; Polarization (electrochemistry) ; Materials science ; Landau quantization ; Relaxation (psychology) ; Band gap ; Physics ; Optoelectronics ; Optics ; Chemistry 2D Materials and Applications ; Perovskite Materials and Applications ; Photonic and Optical Devices
Authors: Dmitri Visser
Source: Research Repository (Delft University of Technology) (article, 2018-12-05)
Field: Materials Science — Biomaterials

Creating a simplified and standardised bioreactor system for tissue-engineered vascular graft culturing and characterisation With the recent developments in tissue-engineered organ substitutes, there has been an increasing demand for novel culturing techniques to create biological substitutes in vitro, as well as reliable and efficient test methods that can assess their biocompatibility and mechanical performance. In the past two decades, perfusion bioreactors have proved to be important tools in the creation, control, and evaluation of cell cultures and engineered tissues under precisely controlled in vitro conditions that simulate the physiological environment. Due to the demanding requirements for blood vessel substitutes, they have been extensively deployed in the culture and conditioning experiments of novel tissue-engineered vascular grafts (TEVGs) and have been often used to study haemodynamic mechanic stimuli, including the cyclic vessel expansion and wall shear stress. However, a key limitation of the currently available TEVG perfusion bioreactors is their often complex design and operation and the lack of standardisation of the mechanical characterisation.&lt;br/&gt;In this study, the goal was to design, characterise, and construct a TEVG perfusion bioreactor that is foremost simpler to operate and extends the capabilities of particular currently available set-ups. A modular bioreactor design is presented that allows for the toolless mounting of the graft with a diameter up to 6 mm and features completely separated circuits for the intra- and extraluminal side of the scaffold wall. The culture chamber encloses a removable graft frame, mainly machined out of polyether ether ketone (PEEK). In silico simulations have been used to assess local fluid dynamics within the scaffold, to predict the reliability of the simulated culture conditions. The presented design allows the exertion of a broad range of physiologically relevant shear stresses on cultured TEVGs, including arterial shear stresses. A test for the in vitro cytotoxicity showed that the medium extracts of the constructed graft frame did not show any cytotoxic potential. Finally, an assessment method for the estimation of the radial compliance is proposed, which aims to adhere to the relevant international standards on the mechanical characterisation of vascular substitutes. Bioreactor ; Scaffold ; Biomedical engineering ; Modular design ; Tissue engineering ; Computer science ; Biochemical engineering ; Engineering ; Chemistry Electrospun Nanofibers in Biomedical Applications ; Tissue Engineering and Regenerative Medicine ; Cardiac and Coronary Surgery Techniques
Authors: T Hoang | L Wu | J Golinval | M Arnst | L Noels | U Hofmann | A Sayed Herbawi | M Holyoak | J Chang | S Hong | Y Kwon | C Jung | M Lee | T Kim | D Cho | Y See Yoon | D Horsley | Y Kusano | G Hou | P See Zhu | Z Hou | D See Xiao | Q Li | M Hu | T Wang | Q Huang | W Deng | S Wang | Y See Ye | C Huber | P Liu | C Krammer | B Stein | H Kalt | M Huff | M See Pedersen | K Ichikawa | S Maeda | Y Yamanishi | S Ihida | F Shaik | Y Ikeuchi | B Ilic | Y Kessler | S Ilyas | N Jaber | M Imboden | C Pollock | O Shekhah | M Eddaoudi | M Younis | J Jackson | Y Zhang | M Jakobsen | M Molgaard | J Javor | E Jeon | S Baek | B Ji | Z See Guo | H Jiang | Y Almoallem | J Fernandes | Y Jin | P Jo | J Gonzalez | J Jones | J Bahari | A Jovic | G Pandraud | N Losilla | J Sancho | K Zinoviev | J Rubio | E Margallo-Ballbas | P Sarro | J Judy | J Rogers | J Juillard | Y Lu | I Jung | D Lopez | Z Qiu | W Piyawattanametha
Source: Journal of Microelectromechanical Systems (article, 2018-12-01)
Field: Materials Science — General Materials Science

2018 Index Journal of Microelectromechanical Systems Vol. 27 Index (typography) ; Microelectromechanical systems ; Computer science ; Materials science ; Nanotechnology ; World Wide Web Material Properties and Applications
Authors: Daniela Bauer
Source: mediaTUM – the media and publications repository of the Technical University Munich (Technical University Munich) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Single-molecule force spectroscopy reveals the domain hierarchy of DnaK NBD and identifies a folding seed and minimal ATP-binding domain of DnaK How proteins adopt their fully functional native 3D structure, is still a puzzling question. In this thesis, the folding behavior of the 45kDa nucleotide-binding domain of DnaK was investigated at a single-molecular level using force spectroscopy. We could decipher the folding path as well as a crucial folding seed for this protein. Moreover, a minimal adenosine-binding domain was designed and structurally and biophysically investigated. These results will help to understand the folding and evolution of other members of the sugar-kinase protein family. Force spectroscopy ; Folding (DSP implementation) ; Cyclic nucleotide-binding domain ; Protein folding ; Biophysics ; Chemistry ; Domain (mathematical analysis) ; Adenosine triphosphate ; Protein domain ; Biology ; Crystallography ; Biochemistry ; Computational biology ; Nucleotide ; Molecule Enzyme Structure and Function ; Force Microscopy Techniques and Applications ; Protein Structure and Dynamics
Authors: Ville Ulvila
Source: Työväentutkimus Vuosikirja (article, 2018-06-12)
Field: Chemistry — Spectroscopy

New method to generate mid-infrared optical frequency combs for molecular spectroscopy In the current study, I experimentally demonstrate a new technique for generating a mid-infrared optical frequency comb (OFC). The motivation for this work stems from importance of coherent light sources to molecular spectroscopy, particularly in the mid-infrared region, where the strong fundamental molecular vibration-rotation absorption bands lie. Coherent light sources are needed to provide the best available sensitivity and selectivity in the spectroscopy experiments. As a prelude for the OFC research, an optical parametric oscillator operating close to signal-idler degeneracy was also examined in this thesis.\n\nThe OFC generator investigated here is based on cascaded quadratic optical nonlinearities (CQNs), an approach that was first discovered as a part of the current study. By applying the new method inside a continuous-wave pumped optical parametric oscillator (OPO), a high-power mid-infrared OFC was produced by simple near-infrared laser pumping.\n\nHere, I present a rigorous experimental study of the new mid-infrared OFC generator. In particular, I verify the CQN comb mode spacing uniformity and demonstrate tuning of the center wavelength, offset frequency, and the mode spacing of the mid-infrared comb. I also apply a parametric seeding technique to improve the spectral quality of the comb. Furthermore, I demonstrate that the CQN method is capable of generating multioctave-spanning composite frequency combs. These results demonstrate the potential of the new OFC generation method for demanding molecular spectroscopy experiments.\n\nUtilization of an OFC source in field applications of molecular spectroscopy requires a robust and compact experimental platform. At the end of this thesis, I present preliminary results of our work towards miniaturization of the CQN comb generator using an optical waveguide device. Infrared ; Spectroscopy ; Molecular spectroscopy ; Infrared spectroscopy ; Optics ; Materials science ; Physics Spectroscopy and Laser Applications ; Advanced Fiber Laser Technologies ; Laser Design and Applications
Authors: A. A. LEONOV
Source: Electronic Theses of LMU Munich (Ludwig-Maximilians-Universität München) (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Mechanistic investigations on various carbon-nucleophiles Annulation of a planar aromatic moiety to cyclopentanone-and cyclohexanone-derived enamines and silyl enol ethers, while influencing the nucleophilicity only slightly, shows significant effects on the sensitivity parameter sN making these substrates less sensitive towards changes in the nature of the electrophile (Figure A.10). Figure A.10.Comparison of the nucleophilicity N and sensitivity sN parameters for various silyl enol ethers and enamines. Carbon fibers ; Nucleophile ; Computer science ; Chemistry ; Algorithm Chemical Reaction Mechanisms
Authors: Pietari Shalah
Source: Theseus (Ammattikorkeakoulujen) (article, 2018-01-01)
Field: Materials Science — Polymers and Plastics

Direct Thermoplastic Impregnation of Leno-Woven Fabric To bring high-performance fiber-reinforced composite parts into the mainstream, the parts need to be molded in minutes, easily recyclable and utilize continuous fibers. Current processing methods and materials rely on difficult-to-recycle thermoset resins and long-cycle-time reaction based molding unsuitable for growing demand. Only recently have manufacturing requirements of fiber reinforced composite surpassed current manufacturing capabilities spawning new methods and materials suited for high-volume production. A new all-glass leno-woven unidirectional (UD) non-crimp fabric (NCF) promising structural stability and high permeability was used to demonstrate its suitability for thermoplastic compression resin transfer molding (TP-CRTM) which borrows concepts from thermoplastic injection molding. Through permeability measurements and compression molding this preliminary study investigates the practical feasibility of TP-CRTM using all-glass leno-woven UD NCF and introduces and implements a technique for high-contrast UV fluorescence microscopy. It was demonstrated that higher molding pressures during thermoplastic compression molding improved saturation of the leno-woven UD NCF without overly distorting the fabric structure and that basic UV fluorescence methods resulted in high-contrast images for void detection. Thermoplastic ; Composite material ; Materials science ; Thermoplastic composites Textile materials and evaluations ; Additive Manufacturing and 3D Printing Technologies
Authors: Emilia Galli
Source: Työväentutkimus Vuosikirja (article, 2018-10-13)
Field: Materials Science — Biomaterials

Development of Analytical Tools for the Quantification of MANF and CDNF in Disease and Therapy Mesencephalic astrocyte-derived neurotrophic factor (MANF) and cerebral dopamine neurotrophic factor (CDNF) are expressed ubiquitously in the body and show protective effects on neurons and other cell types. Although the effects of MANF and CDNF administration have been studied in various animal disease models, such as neurodegenerative diseases, ischemia, and diabetes, it is largely unknown whether their endogenous levels and expression patterns are changed in relation to the pathology of these diseases. \n\nThis thesis describes the development and validation of enzyme-linked immunosorbent assays (ELISAs) for the specific and sensitive quantification of MANF and CDNF in biological samples including serum, tissues, and in vitro cell samples. Since MANF removal leads into a clear diabetic phenotype in mice, we studied the circulating MANF levels in relation to human type 1 diabetes. The aim was to find out whether MANF expression and/or secretion is differently regulated before and at the onset of clinical symptoms of the disease, thus giving insights into its association to type 1 diabetes development in humans.\n\nMultiple studies have demonstrated neuroprotective and neurorestorative effects of MANF and CDNF. Since they are unable to penetrate the blood brain barrier, they need to be delivered within the central nervous system. In this thesis, the effects of intracranial gene therapy of human CDNF were studied in animal models of Parkinson’s and Alzheimer’s disease. Transgene expression depends on multiple variables, such as transduction efficiency, stability, and virus titer. Thus, the quantification of expressed protein is important in the interpretation of its effects. The species-selectivity of the developed ELISAs was utilised when analysing human CDNF levels in rodent brain.\n\nIn addition to gene therapy, long-term protein delivery can be implemented by encapsulated cells that secrete the therapeutic protein to the target site. The developed ELISAs were used for the quantification of secreted CDNF from cells. Despite the successful production of several cell clones with high CDNF expression, its secretion was found to decrease markedly once the cells were confluent in cell culture plates or in polymeric microcapsules. This thesis describes modifications that were done to the CDNF coding sequence to improve its secretion, aiming at efficient delivery of CDNF by encapsulated cell therapy.\n\nThe developed sensitive, specific, and thoroughly validated ELISAs for the quantification of MANF and CDNF can be utilised in future studies aimed at understanding the regulation and functions of these proteins in health and disease. In addition, the ELISAs hold the potential for analysis of these proteins as biomarkers. Computer science Nanoparticle-Based Drug Delivery
Authors: Ryan Hekman
Source: Scholarly Commons (University of the Pacific) (article, 2018-01-01)
Field: Materials Science — Biomaterials

Production of Synthetic Spider Silk Spider silk is a material that both has impressive mechanical properties and is also environmentally friendly. Though there are limitless potential engineering applications for such materials, industrial production of spider silk has proven to be challenging. Farming silk from spiders, as is done with silkworms, is not a viable option for large-scale production of spider silk due to the venomous and predatory nature of spiders. Here, an attempt is made to express synthetic spider silk minifibroins heterologously in Escherichia coli, to purify the recombinant spidroins from cell lysate, and to spin them into artificial fibers through a biomimetic process. Silk minifibroins were designed to be similar to Major Ampullate Spidroin 1 from Latrodectus hesperus. Synthetic fibers were examined by scanning electron and light microscopy, and their mechanical properties were tested by a tensometer. Properties of synthetic silk were compared to those of native dragline silk from the same species from which their design was inspired, revealing synthetic silk fibers with lower breaking stress and breaking strain. Spider silk ; SILK ; Spider ; Production (economics) ; Computer science ; Biology ; Economics ; Zoology Silk-based biomaterials and applications ; Silkworms and Sericulture Research
Authors: Megan Briggeman | Mengchen Huang | Anthony Tylan‐Tyler | Jung-Woo Lee | Hyungwoo Lee | Chang‐Beom Eom | Patrick Irvin | Jeremy Levy
Source: D-Scholarship@Pitt (University of Pittsburgh) (article, 2018-03-05)
Field: Materials Science — Materials Chemistry

Experimental Solid State Quantum Simulation Using 1D Superlattice Structures In this thesis we describe experiments which explore 1D transport at the LaAlO3/SrTiO3 interface. Complex oxide systems, specifically those based on SrTiO3, possess a wide range of magnetic and electronic properties, including superconductivity, magnetism, ferroelectricity, and ferroelasticity. Electron waveguide devices created at the LaAlO3/SrTiO3 interface exhibit quantized ballistic transport of electrons, electron pairs, and Pascal liquid phases-bound states of more than two electrons. Different types of periodic modulation are applied to the electron waveguides to create one-dimensional superlattices. By creating superlattice devices we are able to engineer new properties and enhance electron-electron interactions at the LaAlO3/SrTiO3 interface. These devices represent a first step towards developing a solid-state quantum simulation platform and will be used as building blocks for creating more complex quantum systems. Superlattice ; Electron ; Magnetism ; Condensed matter physics ; Quantum ; Ferroelectricity ; Superconductivity ; Materials science ; Physics ; Optoelectronics ; Quantum mechanics Electronic and Structural Properties of Oxides ; Semiconductor Lasers and Optical Devices ; Geophysics and Sensor Technology
Authors: G Tumminelli
Source: Nova Science Publishers (Nova Science Publishers, Inc.) (article, 2018-09-13)
Field: Materials Science — Materials Chemistry

DEVELOPMENT OF A NEW SATURATED VAPOUR-ANODE, SATURATED VAPOUR-CATHODE AMTEC-LIKE DEVICE Cathode ; Anode ; Materials science ; Electrical engineering ; Chemistry ; Electrode ; Engineering Silicone and Siloxane Chemistry
Authors: Keane Tobin
Source: Saint Mary's University Institutional Repository (Saint Mary's University) (article, 2018-01-01)
Field: Chemistry — Spectroscopy

An OP-FTIR trace gas observatory : design, automation, and applications Observatory ; Fourier transform infrared spectroscopy ; Trace gas ; Process engineering ; Environmental science ; Computer science ; Chemistry ; Engineering ; Physics ; Chemical engineering ; Astronomy ; Organic chemistry Spectroscopy and Laser Applications ; Atmospheric and Environmental Gas Dynamics ; Atmospheric Ozone and Climate