jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Jacob Henshaw
Source: CUNY Academic Works (City University of New York) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Charge State Dynamics and Quantum Sensing with Defects in Diamond In recent years, defect centers in wide band gap semiconductors such as diamond, have received significant attention. Defects offer great utility as single photon emitters, nanoscale sensors, and quantum memories and registers for quantum computation. Critical to the utility of these defects, is their charge state. In this dissertation, experiments surrounding the charge state dynamics and the carrier dynamics are performed and analyzed. Extensive studies of the ionization and recombination processes of defects in diamond, specifically, the Nitrogen Vacancy (NV) center, have been performed. Diffusion of ionized charge carriers has been imaged indirectly through the recapture of said carriers by optically active defects such as the NV center and the Silicon Vacancy (SiV) center. With proper understanding of the carrier dynamics, diamond stands to be a strong competitor in the field of spintronics for quantum information processing. Additionally, the understanding of these charge state dynamics is utilized in a novel proof of principle experiment, showing that the NV center defect’s charge state could serve as an ultra-dense 3D memory platform. The NV center has also been used as a nanoscale magnetometer. The high degree of spin polarization and the ease of manipulation of the NV allows us to transfer this polarization to other spins in the diamond and assists in the detection of spins outside of the diamond. Ensembles of Nitrogen Vacancy centers can be used to perform NMR spectroscopy of sample volumes not achievable through traditional methods. The operating mechanisms of the magnetic resonance aspects of the NV center will be discussed in depth. Work surrounding the control and polarization of the NV center’s host nitrogen spin will be covered. The topic of sensitivity and methods to improve that sensitivity will be covered as well. Charge (physics) ; Quantum ; Statistical physics ; Diamond ; Physics ; State (computer science) ; Quantum mechanics ; Materials science ; Computer science ; Algorithm Diamond and Carbon-based Materials Research ; Carbon Nanotubes in Composites ; Force Microscopy Techniques and Applications
Authors: Geoffrey Ijeomah | Fahmi Samsuri | Felix Obite | Mohamad Adzhar Md Zawawi
Source: International Journal of Engineering Technology and Sciences (article, 2018-12-27)
Field: Materials Science — Materials Chemistry

Theoretical Modelling of Charge Transport Properties of Individual Single-Wall Carbon Nanotubes Experimental projection of transport properties of semiconductor devices faces a challenge nowadays. As devices scale to nanometre scale range, the classical transport equations used in current device simulators can no longer be applied. Conversely, the use of a more accurate and better non-equilibrium green function (NEGF) is limited by the fact that it requires excessive quantum of memory and computational time, having quasi-separable matrices that are extremely convoluted to solve. This work exploits the Boltzmann Transport Equation (BTE) to assess the transport properties of carbon nanotubes. Previous works on solving the BTE have employed either a stochastic method or an approximate method, both of which do not possess the necessary properties for practical device applications. Therefore, this work represents the first direct theoretical solution of the BTE for one-dimensional carbon nanotubes that can be utilized for practical device applications. The complete spectrum of transport in CNTs extending from ohmic to high-field through ballistic transmission is examined to delineate plethora of transport properties. The transport for arbitrary values of the electric field is based on the BTE applied to experimental data on CNTs. In the limit of low field, the mobility expressions are obtained in terms of the mean free path (mfp) that is distinctly shorter than the length of the sample. The ohmic resistance is quantized a value of 6.453k-ohms consistent with experimental findings with transmission approaching unity as channel length shrinks below the carrier mfp. The emission of a quantum was observed to lower the saturation velocity that is independent of scattering and hence ballistic. Transition to ballistic domain was found to occur when the channel length is scaled below the ballistic limit that is shown to be the extended version of the long-channel mfp modulated by injections from the contacts, yet the mobility degrades. The mobility degradation is shown to be the cause of resistance quantum in the low-channel length limit. These findings are important in predicting the transport properties of low-dimensional CNTs. Ohmic contact ; Carbon nanotube ; Ballistic conduction ; Boltzmann equation ; Mean free path ; Computational physics ; Statistical physics ; Physics ; Quantum ; Ballistic conduction in single-walled carbon nanotubes ; Materials science ; Condensed matter physics ; Nanotechnology ; Quantum mechanics ; Electron ; Optical properties of carbon nanotubes ; Nanotube Carbon Nanotubes in Composites ; Graphene research and applications ; Nanopore and Nanochannel Transport Studies
Authors: Annie Chang | Vicente Compañ Moreno | Barry A. Weissman
Source: RiuNet (Politechnical University of Valencia) (article, 2018-01-01)
Field: Chemistry — Spectroscopy

Evolution of the critical oxygen tension Chang, A.; Compañ Moreno, V.; Weissman, BA. (2018). Evolution of the critical oxygen tension. Contact Lens Spectrum. 33(3):36-39. http://hdl.handle.net/10251/121358 Oxygen ; Chemistry Mass Spectrometry Techniques and Applications ; Protist diversity and phylogeny ; Microbial Community Ecology and Physiology
Authors: Muhammad Muniruzzaman | Massimo Rolle
Source: Technical University of Denmark, DTU Orbit (Technical University of Denmark, DTU) (article, 2018-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Coulombic effects during conservative and reactive transport of charged solutes in homogeneous and heterogeneous porous media: Experiments and modeling Homogeneous ; Porous medium ; Porosity ; Chemistry ; Chemical physics ; Chemical engineering ; Thermodynamics ; Physics ; Organic chemistry ; Engineering Electrostatics and Colloid Interactions ; Analytical Chemistry and Sensors ; Microfluidic and Capillary Electrophoresis Applications
Authors: Rizvan M. Guseynov | Kheiyrulla M. Makhmudov | R. A. Radzhabov | Zumrud N. Bakhmudkadieva | Zaripat A. Zaynutdinova
Source: IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA (article, 2018-07-12)
Field: Chemistry — Electrochemistry

BEHAVIOR OF BLOCKING (INERT) ELECTRODE / SOLID ELECTROLYTE INTERFACE IN GALVANOGARMONIC CHARGING MODE. CASE OF DECELERATED DIFFUSION AND ADSORPTION –DESORPTION OF TWO DIFFERENT KINDS OF PARTICLES Electrochemical behavior of a cell with an interface of blocking electrode /solid electrolyte was studied in galvanogarmonic mode of charge. The possibility of application of simple and more graphic calculation technique and separation of electrochemical impedance schemes into active and reactive constituents was shown. The Jacobsen-West diffusion model was used as an equivalent electric circuit, which is valid for relatively large times or low AC frequencies. The plotting of dependences of active and reactive impedance components on AC frequency was used in order to estimate the values of parameters for studied equivalent electric circuits. Electrolyte ; Electrode ; Diffusion ; Electrochemistry ; Equivalent circuit ; Electrical impedance ; Inert ; Electrochemical cell ; Blocking (statistics) ; Desorption ; Analytical Chemistry (journal) ; Materials science ; Chemistry ; Adsorption ; Voltage ; Thermodynamics ; Chromatography ; Electrical engineering ; Physical chemistry ; Organic chemistry ; Physics Electrochemical Analysis and Applications ; Ionic liquids properties and applications ; Electrostatics and Colloid Interactions
Authors: Yiran Chen
Source: eScholarship (California Digital Library) (article, 2018-01-01)
Field: Chemistry — Spectroscopy

Innovative Methodology and Applications of Diffusion-tensor and Hyperpolarized Carbon-13 Magnetic Resonance Imaging in Pediatric Brain Development Pediatric magnetic resonance imaging (MRI) emerged as an independent research area from adult MRI, due to distinct brain structure and development trajectory, and different responses to brain injuries or diseases in pediatric subjects. This dissertation discussed a few unexplored but important areas in pediatric brain MRI, including diffusion tensor imaging (DTI) and hyperpolarized 13C spectroscopic imaging. DTI is adversely affected by subject motion, which is a common problem among unsedated pediatric subjects. It is necessary to discard the corrupted images before diffusion parameter estimation. However, the consequences of rejecting those images were not well understood. We investigated the effects of excluding one or more volumes of diffusion weighted images by analyzing the changes in diffusion parameters. Based on the full set of diffusion images, we generated incomplete sets in three different ways: random, uniform and clustered rejections. Different rejection methods resulted in very different variations in DTI parameters, and sometimes the resulting accuracy depended on the relative orientation of the underlying fibers with respect to the excluded directions. In practice, if diffusion data is excluded, it is important to note the number and location of directions rejected, in order to make a more precise analysis of the results.Structural changes during early brain development have been studied using conventional MRI methods, but metabolic changes remain unrevealed. Hyperpolarized 13C spectroscopic imaging has recently been used to dynamically image metabolism in vivo. This technique provides the capability to investigate metabolic changes in mouse brain development over multiple time points. We used hyperpolarized 13C-1 labeled pyruvate to analyze its conversion into lactate during early brain development in normal and hypoxic-ischemic (HI) injured brains. The produced lactate level decreased linearly with increasing age in normal brains, but no pattern was observed in HI brains. This technique was also able to detect HI injury at a very early stage within a very short amount of time, which was hardly discovered otherwise. It can be a potential marker for HI diagnosis and progression tracking. Diffusion MRI ; Magnetic resonance imaging ; Neuroimaging ; Orientation (vector space) ; Diffusion ; Brain development ; Nuclear magnetic resonance ; Computer science ; Artificial intelligence ; Neuroscience ; Psychology ; Nuclear medicine ; Medicine ; Physics ; Mathematics ; Radiology Advanced NMR Techniques and Applications ; Advanced MRI Techniques and Applications ; Atomic and Subatomic Physics Research
Authors: A. Lier
Source: Max Planck Digital Library (article, 2018-01-01)
Field: Materials Science — Surfaces, Coatings and Films

Kinetic Modeling of Runaway Electron Dynamics One of the problems that reactor-relevant tokamaks face are plasma terminating disruptions.Under certain circumstances a beam of high energy electrons, so-called runaway electrons (REs) can form, which pose serious damage to the plasma facing components.In this thesis I numerically investigate the dynamics of REs using the relativistic, full-f, linearized kinetic (Fokker-Planck) solver CODE ("COllisional Distribution of Electrons") for experimentally relevant scenarios.After a theoretical introduction into the kinetic solver applied here, I apply basic validation, testing and convergence scans.The first type of experimentally relevant case investigated is a "flat-top" scenario.Here runaways are formed under quiescent (flat-top) parts of a regular tokamak discharge.We were trying to understand if CODE is suitable to model FTU (Frascati Tokamak Upgrade) flat-top cases and provide distributions suitable for experimental comparisons.I made an extensive parameter scan to study the effect of individual plasma parameters on the evolution of the distribution.I have found that simply using the data as supplied would lead to a significant overproduction of REs in the simulation.The experimental discrepancy can possibly be explained by measurement uncertainties or runaway transport in the flat-top scenario due to e.g.turbulence.The second (and more challenging) application is the case of post-disruption runaway generation for an ASDEX Upgrade (AUG) disruption case.This part of the project requires self-consistent treatment of the electric field, which introduces numerical complications, and makes the calculations significantly slower.I discuss a number of cases where numerical issues were not possible to resolve in the given timeframe.I finally close with a successful calculation for a post-disruptive runaway beam case.This is first time it had been possible to calculate RE generation for an AUG-like disruption using a full-f solver with a self-consistent electric field. Dynamics (music) ; Statistical physics ; Kinetic energy ; Physics ; Computer science ; Classical mechanics Electron and X-Ray Spectroscopy Techniques ; Advanced Chemical Physics Studies ; Atomic and Molecular Physics
Authors: Ahmed Sid-Ali
Source:  (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Un processus empirique à valeurs mesures pour un système de particules en interaction appliqué aux réseaux complexes Un processus empirique valeurs mesures pour un systme de particules en interaction appliqu aux rseaux complexesThse Physics Pickering emulsions and particle stabilization ; Slime Mold and Myxomycetes Research ; Adsorption, diffusion, and thermodynamic properties of materials
Authors: Shipra Baluja | Ashish Patel
Source: emergent Life Sciences Research (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Physicochemical properties of some tetrahydropyrimidine derivatives Production of tetrahydropyrimidine and their derivatives is of great importance in organic chemistry. Presence of pyrimidine piece in different biological compounds that are used in several medications makes it a crucial component. In this study, some new tetrahydropyrimidine compounds are synthesized and their physicochemical properties such as such as density, refractive index, partition coefficients have been studied in different solvents at 308.15K. Chemistry ; Biochemical engineering ; Environmental chemistry ; Engineering Synthesis of Tetrazole Derivatives ; Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and biological activity
Authors: Pierpaolo Minei | Marco Lessi | Marco Geppi | Tarita Biver | Gaetano Angelici | Giacomo Ruggeri | Andrea Pucci | Fabio Bellina
Source: CINECA IRIS Institutial research information system (University of Pisa) (article, 2018-01-01)
Field: Chemistry — Inorganic Chemistry

COOLSUN: Studio preliminare sulle proprietà “cool” dei pigmenti organici Il 50% dell'energia solare che raggiunge la terra viene emesso nella regione del vicino infrarosso (NIR) e non è rilevabile dall'occhio umano. L'assorbimento nel NIR da parte di un oggetto provoca un aumento della sua temperatura1. I pigmenti che interagiscono con la porzione NIR dello spettro solare (vale a dire tra 700 e 1600 nm) senza assorbirla sono chiamati NIR trasparenti e il loro uso riduce il riscaldamento dei substrati trattati2. Tale proprietà è utile in applicazioni in cui il riscaldamento solare deve essere attenuato: pelletteria, edilizia, coperture di serre, rivestimento e trasporto di materiali sensibili al calore3. Alcuni pigmenti, oltre alla trasparenza, hanno la proprietà di riflettere la radiazione NIR. Oggi la riflettività NIR si ottiene con l'uso di pigmenti inorganici (TiO2, ossidi e complessi metallici) che sono costosi e, in alcuni casi, tossici1. La chiave per ottenere rivestimenti innovativi è quindi la produzione di pigmenti NIR-riflettenti di natura organica in modo da superare i problemi relativi ai costi, all'impatto ambientale, all'efficienza e all'indice cromatico degli attuali pigmenti inorganici presenti sul mercato4. L'obiettivo del nostro lavoro è lo sviluppo di prodotti innovativi contenenti pigmenti organici NIR riflettenti e/o trasparenti. In questa fase preliminare del nostro progetto ci siamo concentrati sullo studio delle proprietà "cool" dei pigmenti commerciali al fine di essere in grado di progettare e sviluppare pigmenti organici, termo- e fotostabili, in grado di riflettere la radiazione nel NIR. I pigmenti sono stati inizialmente dispersi in una matrice polimerica, la miscela prodotta è stata quindi applicata su pannelli di prova bianchi (massima riflessione) e neri (assorbimento massimo). La percentuale di riflettanza dei pannelli trattati con ciascun pigmento è stata determinata utilizzando uno spettrofotometro UV-Vis-NIR. Le miscele pigmento/matrice sono state applicate su campioni di pelle e le loro proprietà “cool” sono state determinate mediante l’impiego di una termocamera dopo irraggiamento con una lampada a infrarossi. Studio ; Art ; Visual arts Pigment Synthesis and Properties
Authors: Yaokai Duan
Source: eScholarship (California Digital Library) (article, 2018-01-01)
Field: Materials Science — Biomaterials

Fluorescence Labeling and Limited Proteolysis for Demystifying Protein Corona Engineered nanomaterials (ENMs) have great application potentials in biological systems, while the protein corona formed around ENMs after they encounter any biofluids makes their fate difficult to be predicted. Protein corona provides a brand new âbiological identifyâ for ENMs, which will determine the recognition, targeting, and compatibility of ENMs in vivo. One important property of protein corona is its dynamic exchange of components during incubation time, on which lots of endeavors have been made, but there is still knowledge gap between the intrinsic properties of ENMs and what kinds of protein will form the corona. Moreover, the molecular details of protein in corona, including the orientation, conformational change and aggregation, are also important for the function of protein corona. Due to the non-specific forces behind protein-ENMs interactions, desired and controlled arrangement of protein on ENMs surface has always been a significant but difficult task. Despite of various success made on those two topics, rapid and routine methods for composition analysis and molecular details exploration of protein corona are still in stark deficient. This research will focus on new methods development for those two problems. Firstly, a fluorescamine labeling based high throughput screening method is applied to screen and discriminate interactions between single protein and ENMs, which could indicate either protein binding or unfolding induced by ENMs. With those results as descriptors, correlations between them and protein corona composition have been found, which suggests that a structure activity quantification model using those descriptors could be built for rapid corona prediction. Secondly, limited proteolysis coupled with LC-MS/MS capable to identify binding sites of protein on another molecule has been developed. By applying it to those positive protein-ENMs pairs identified in previous screening, the molecular details including orientation and unfolding of proteins in corona could be unveiled. Despite of the limitation on precision, information obtained from this method could be helpful for further rational design of ENMs on biological application. Corona (planetary geology) ; Chemistry ; Proteolysis ; Nanotechnology ; Biophysics ; Biochemistry ; Biology ; Materials science Nanoparticle-Based Drug Delivery ; Biological Research and Disease Studies
Authors: Shireesh Apte
Source: International Journal of Pharmaceutical Excipients (article, 2018-12-08)
Field: Materials Science — Materials Chemistry

Dimensional analysis as a tool to predict, identify and decipher the relative magnitude effects of known and unknown physicochemical properties that influence the solubilizing effectiveness of solubility modifiers and/or complexing agents. None DECIPHER ; Biochemical engineering ; Solubility ; Biological system ; Chemistry ; Computer science ; Bioinformatics ; Biology ; Organic chemistry ; Engineering Crystallization and Solubility Studies ; Analytical Chemistry and Chromatography ; Thermal and Kinetic Analysis
Authors: Anna Grebinyk | Svitlana Prylutska | І. І. Grynyuk | Benjamin Kolp | Vasyl V. Hurmach | T.Yu. Sliva | Vladimir M. Аmirkhanov | V.A. Trush | Olga Matyshevska | Nikolay S. Slobodyanik | Yu. І. Prylutskyy | Marcus Frohme | Uwe Ritter
Source: Nanoscale Research Letters (article, 2018-03-09)
Field: Chemistry — Organic Chemistry

C60 Fullerene Effects on Diphenyl-N-(trichloroacetyl)-amidophosphate Interaction with DNA In Silico and Its Cytotoxic Activity Against Human Leukemic Cell Line In Vitro New representative of carbacylamidophosphates - diphenyl-N-(trichloroacetyl)-amidophosphate (HL), which contains two phenoxy substituents near the phosphoryl group, was synthesized, identified by elemental analysis and IR and NMR spectroscopy, and tested as a cytotoxic agent itself and in combination with C<sub>60</sub> fullerene.According to molecular simulation results, C<sub>60</sub> fullerene and HL could interact with DNA and form a rigid complex stabilized by stacking interactions of HL phenyl groups with C<sub>60</sub> fullerene and DNA G nucleotide, as well as by interactions of HL CCl<sub>3</sub> group by ion-π bonds with C<sub>60</sub> molecule and by electrostatic bonds with DNA G nucleotide.With the use of MTT test, the cytotoxic activity of HL against human leukemic CCRF-CM cells with IC<sub>50</sub> value detected at 10 μM concentration at 72 h of cells treatment was shown. Under combined action of 16 μM C<sub>60</sub> fullerene and HL, the value of IC<sub>50</sub> was detected at lower 5 μM HL concentration and at earlier 48 h period of incubation, besides the cytotoxic effect of HL was observed at a low 2.5 μM concentration at which HL by itself had no influence on cell viability. Binding of C<sub>60</sub> fullerene and HL with minor DNA groove with formation of a stable complex is assumed to be one of the possible reasons of their synergistic inhibition of CCRF-CЕM cells proliferation.Application of C<sub>60</sub> fullerene in combination with 2.5 μM HL was shown to have no harmful effect on structural stability of blood erythrocytes membrane. Thus, combined action of C<sub>60</sub> fullerene and HL in a low concentration potentiated HL cytotoxic effect against human leukemic cells and was not followed by hemolytic effect. Fullerene ; DNA ; MTT assay ; Stacking ; IC50 ; Cytotoxicity ; Cytotoxic T cell ; Chemistry ; Viability assay ; Stereochemistry ; In vitro ; Biochemistry ; Organic chemistry Fullerene Chemistry and Applications ; Carbon Nanotubes in Composites ; Graphene research and applications