jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Julian Meyer‐Kirschner | Alexander Mitsos | Jörn Viell
Source: Journal of Raman Spectroscopy (article, 2018-05-10)
Field: Chemistry — Analytical Chemistry

Polymer particle sizing from Raman spectra by regression of hard model parameters Abstract The particle size of polymer colloids is a key characteristic. It directly affects Raman measurements due to light scattering by particles. This publication exploits the extent to which these spectral changes can be correlated to the particle sizes by using a spectral hard model and data‐driven model. To this end, spectra of aqueous polystyrene nanoparticles are decomposed into pure component spectral models by means of indirect hard modeling (IHM). Each pure component model is characterized by multiple peak‐shaped Voigt profiles. By fitting the model to spectra of polymer colloids, spectral changes due to light scattering by particles are incorporated in the model parameters. The resulting parameter values are used as input for data‐driven partial least squares (PLS) regression to extract particle sizes. The method is applied to Raman spectra of polystyrene nanoparticles of 23–60 nm diameter measured repeatedly at concentrations 0.17–1 wt%. The hybrid model predicts the particle size with R 2 = 0.99. In contrast, purely data‐driven PLS regression of the spectral intensities with 3 latent PLS variables results in R 2 from 0.78 to 0.83. Resulting PLS scores portray a clear differentiability of Raman scattering and light scattering by particles within IHM model parameters. PLS regression coefficients further allow identification of individual peak parameters that correlate with particle size, which substantiates previous findings on correlation between Raman signal and scattering by polymer colloids. Combining IHM and data‐driven PLS regression demonstrates more accurate prediction of particle size for extended usage of Raman spectroscopy as comprehensive process analytical technology to determine sample concentrations and particle data. Raman spectroscopy ; Partial least squares regression ; Particle (ecology) ; Particle size ; Polystyrene ; Materials science ; Light scattering ; Raman scattering ; Spectral line ; Analytical Chemistry (journal) ; Polymer ; Scattering ; Chemistry ; Optics ; Physics ; Statistics ; Mathematics ; Chromatography ; Composite material ; Physical chemistry Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Water Quality Monitoring and Analysis
Authors: Ali Javid | Farid Moeinpour
Source: Bulletin of the Chemical Society of Ethiopia (article, 2018-11-26)
Field: Chemistry — Organic Chemistry

Ni0.5Zn0.5Fe2O4@HA-PRS nanoparticle: A recoverable green catalyst for the synthesis of tetrahydrobenzo[b]pyrans in water A green, efficient and simple technique for the synthesize of tetrahydrobenzo[b]pyrans through one-pot three-component reaction of dimedone, aromatic aldehydes and malonitrile as active methylene compound using immobilization of Preyssler heteropoly acid on Ni0.5Zn0.5Fe2O4 magnetite nanoparticles (MNPs), coated with hydroxyapatite (HA) as a catalyst is described. Comparing with the previous studies on preparation of these compounds, the present methodology suggests some benefits which include high yields, short reaction times and green reaction conditions (room teperature in H2O). More importantly, the magnetic catalyst was isolated from the reaction mixture using a simple magnet and efficiently reused at least five runs without any loss of catalytic activity. Thus, the developed separable catalysts are potentially beneficial for the economic production of organic compounds. KEY WORDS: One-pot, Three-component, Tetrahydrobenzo[b]pyrans, Preyssler, Heteropoly acid, Magnetite nanocatalyst Bull. Chem. Soc. Ethiop. 2018, 32(3), 501-511.DOI: https://dx.doi.org/10.4314/bcse.v32i3.9 Dimedone ; Chemistry ; Catalysis ; Magnetite ; Methylene ; Multi-component reaction ; Nanoparticle ; Nuclear chemistry ; Magnetite Nanoparticles ; Reaction conditions ; Magnetic nanoparticles ; Organic chemistry ; Chemical engineering ; Metallurgy Chemical Synthesis and Reactions ; Multicomponent Synthesis of Heterocycles ; Polyoxometalates: Synthesis and Applications
Authors: Nathan S. Babcock | D.A. Keedy | James S. Fraser | David A. Sivak
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2018-10-20)
Field: Materials Science — Materials Chemistry

Model Selection for Biological Crystallography Structural biologists have fit increasingly complex model types to protein X-ray crystallographic data, motivated by higher-resolving crystals, greater computational power, and a growing appreciation for protein dynamics. Once fit, a more complex model will generally fit the experimental data better, but it also provides greater capacity to overfit to experimental noise. While refinement progress is normally monitored for a given model type with a fixed number of parameters, comparatively little attention has been paid to the selection among distinct model types where the number of parameters can vary. Using metrics derived in the statistical field of model comparison, we develop a framework for statistically rigorous inference of model complexity. From analysis of simulated data, we find that the resulting information criteria are less likely to prefer an erroneously complex model type and are less sensitive to noise, compared to the crystallographic cross-validation criterion R free . Moreover, these information criteria suggest caution in using complex model types and for inferring protein conformational heterogeneity from experimental scattering data. Overfitting ; Model selection ; Computer science ; Selection (genetic algorithm) ; Noise (video) ; Inference ; Algorithm ; Experimental data ; Information Criteria ; Data mining ; Artificial intelligence ; Biological system ; Statistical physics ; Mathematics ; Statistics ; Biology ; Physics Enzyme Structure and Function ; Protein Structure and Dynamics ; Molecular Biology Techniques and Applications
Authors: Kashif Ishfaq | Nadeem Ahmad Mufti | Muhammad Jawad | Muhammad Sajid | Mirza Jahanzaib
Source: Advances in Science and Technology – Research Journal (article, 2018-03-01)
Field: Materials Science — Materials Chemistry

Analysis of the Effect of Wire Electric Dischage Machining Process Parameters for the Formation of High Speed Steel Form Tool The use of form tools is growing in industry, owing to their inherent advantage of improving productivity. However, the accurate formation of form tool profile is a really tedious task. In this research work, wire electric discharge machining (WEDM) process has been used for the generation of a form tool. Pulse on-time, pulse off-time, servo voltage, wire tension, flushing pressure have been considered as input parameters, whereas tool geometry (clearance angle, included angle), surface roughness and material removal rate are the selected responses. Response surface methodology (RSM) (Box Bhenken experimental design) technique has been used for design of experiments. Analysis of Variance (ANOVA) has shown that pulse on-time and pulse off-time are the two influential control factors for material removal rate (MRR), surface roughness (Ra), clearance angle and included angle. Contour plot analysis has been performed to find out the optimal ranges of the most influential control factors for each response characteristics. Process (computing) ; Machining ; Mechanical engineering ; Materials science ; Electrical discharge machining ; Engineering drawing ; Manufacturing engineering ; Metallurgy ; Computer science ; Engineering Metal Alloys Wear and Properties ; Engineering Technology and Methodologies ; Advanced machining processes and optimization
Authors: Selvia M. Adly | Maha M. Abdelrahman | Nada S. Abdelwahab | Nourudin Wageh Ali
Source: European Journal of Chemistry (article, 2018-12-31)
Field: Chemistry — Analytical Chemistry

Different spectrophotometric and TLC-densitometric methods for determination of olmesartan medoxomil and hydrochlorothiazide and their degradation products In this work, multivariate calibration models and TLC-densitometric methods have been developed and validated for quantitative determination of olmesartan medoxomil (OLM) and hydrochlorothiazide (HCZ) in presence of their degradation products, olmesartan (OL) and salamide (SAL), respectively. In the first method, multivariate calibration models including principal component regression (PCR) and partial least square (PLS) were applied. The wavelength range 210-343 nm was used and data was auto-scaled and mean centered as pre-processing steps for PCR and PLS models, respectively. These models were tested by application to external validation set with mean percentage recoveries 99.78, 100.01, 100.41 and 100.46% for OLM, HCZ, OL and SAL, respectively, for PLS model and also, 100.22, 100.40, 102.25 and 100.13% for them, respectively, for PCR model. The second method is TLC-densitometry at which the chromatographic separation was carried out using silica gel 60F254 TLC plates and the developing system consisted of a mixture of ethyl acetate:chloroform:methanol: formic acid:tri-ethylamine (60:40:4:4:1, by volume) with UV-scanning at 254 nm. The developed methods were successfully applied for determination of OLM and HCZ in their pharmaceutical dosage form. Also, statistical comparison was made between the developed methods and the reported method using student’s-t test and F-test and results showed that there was no significant difference between them concerning both accuracy and precision. Olmesartan ; Chromatography ; Chemistry ; Hydrochlorothiazide ; Densitometry ; Partial least squares regression ; Densitometer ; Silica gel ; Linear regression ; Chemometrics ; Analytical Chemistry (journal) ; Mathematics Analytical Methods in Pharmaceuticals ; Pesticide Residue Analysis and Safety ; Analytical Chemistry and Chromatography
Authors: Lindsay Bassman Oftelie | Pankaj Rajak | Rajiv K. Kalia | Aiichiro Nakano | Fei Sha | Muratahan Aykol | Patrick Huck | Kristin A. Persson | Jifeng Sun | David J. Singh | Priya Vashishta
Source: MRS Advances (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Efficient Discovery of Optimal N-Layered TMDC Hetero-Structures Materials science ; Bayesian optimization ; Electronic structure ; Band gap ; Electronic band structure ; Thermoelectric effect ; Gaussian ; Thermoelectric materials ; Computer science ; Condensed matter physics ; Optoelectronics ; Thermodynamics ; Thermal conductivity ; Machine learning ; Physics ; Quantum mechanics 2D Materials and Applications ; Machine Learning in Materials Science ; Advanced Thermoelectric Materials and Devices
Authors: Eryn Kwon | Michael R Singh | Ravin D Vallabh | Raj Das | Michael Taylor | Justin Fernandez
Source: Computer Methods in Biomechanics and Biomedical Engineering Imaging & Visualization (article, 2018-07-31)
Field: Materials Science — Materials Chemistry

Modelling ballistic cranial injury and backspatter using smoothed particle hydrodynamics ABSTRACT Forensic investigation has the primary challenge of assessing cause from limited evidence. The use of computational modelling can play a role in assessing potential ballistic pathways in a crime investigation by analysing; (a) the entry wound and blood spatter patterns; (b) the influence of target materials; and (c) the cranial geometry, to inform the investigation process. In particular, the retrograde ejection of blood and tissue from the entry wound following projectile impact, called ‘backspatter’, and can help inform the proximity of the shooter and potentially differentiate between suicide and homicide, while providing other important forensic information. However, the ‘backspatter’ phenomenon is not well understood due to the lack of viable surrogate models and the difficulties of analysing the high-speed, extreme-force impact. This study presents (i) the development of an anatomically based model of cranial ballistic injury using the Smoothed Particle Hydrodynamics (SPH) method; (ii) the simulation of the tail splashing and temporary cavitation mechanisms and the effect of different cranial skin and cranium simulants on backspatter generation; (iii) an evaluation of anatomical geometry simulation results such as stress and strain and velocity of the particles ejected as backspatter; and (iv) a parametric study of the effect of bullet calibre and speed on the ballistic response of the anatomical geometry computational model. Smoothed-particle hydrodynamics ; Projectile ; Ballistics ; Ballistic impact ; Parametric statistics ; Mechanics ; Impact ; Computer science ; Physics ; Simulation ; Classical mechanics ; Mathematics High-Velocity Impact and Material Behavior ; Fluid Dynamics Simulations and Interactions ; Structural Response to Dynamic Loads
Authors: Huy Do Hoang | Julia Janke | Aneta Amirjanyan | Tariel V. Ghochikyan | Anika Flader | Alexander Villinger | Peter Ehlers | Stefan Lochbrunner | Annette‐Enrica Surkus | Peter Langer
Source: Organic & Biomolecular Chemistry (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Synthesis of furo[3,2-<i>b</i>:4,5-<i>b</i>′]diindoles and their optical and electrochemical properties An efficient two-step palladium catalyzed synthesis of furo[3,2-b:4,5-b']diindoles, a hitherto unknown symmetrical heterocyclic core structure, was developed. The synthesis is based on a regioselective Suzuki-Miyaura cross coupling reaction of tetrabromofuran and subsequent double N-arylation. Selected compounds were studied with regard to their optical and electrochemical properties. The compounds show fluorescence with high quantum yields and non-reversible oxidation events. The compounds possess similar HOMO-LUMO band gaps compared to their sulfur and nitrogen analogs. Variation of the substituents hardly affects the HOMO-LUMO gap, but allows for some fine-tuning of the electron affinity and ionization potential as well as quantum yields. The compounds prepared represent interesting candidates for the development of organic electronic materials. Chemistry ; Electrochemistry ; Combinatorial chemistry ; Stereochemistry ; Physical chemistry ; Electrode Catalytic C–H Functionalization Methods ; Synthesis of Indole Derivatives ; Catalytic Cross-Coupling Reactions
Authors: Nicolai D. Knöfel | Caroline Schweigert | Thomas J. Feuerstein | Christoph Schoo | Niklas Reinfandt | Andreas‐Neil Unterreiner | Peter W. Roesky
Source: Inorganic Chemistry (article, 2018-07-25)
Field: Chemistry — Organic Chemistry

Dimolybdenum Paddlewheel as Scaffold for Heteromultimetallic Complexes: Synthesis and Photophysical Properties A diphenylphosphine functionalized benzoic acid was applied for the synthesis of a homoleptic dimolybdenum-based metalloligand, exhibiting four symmetrically placed phosphine donor sites. This allowed subsequent treatment with gold(I), rhodium(I), and iridium(I) precursors to obtain early-late heterometallic complexes as well as Lewis acid-base adducts with BH<sub>3</sub>. The compounds were in-depth investigated by spectroscopic techniques, single-crystal X-ray diffraction, and femtosecond laser spectroscopy. The coordination of different metal fragments to the dimolybdenum metalloligand leads to a fine-tuning of the system's optical properties, which correlates well with fluorescence quantum yield measurements. Nevertheless, triplet dynamics still remain the dominating channel in these systems with an intersystem crossing time constant below 1 ps. Chemistry ; Scaffold ; Combinatorial chemistry ; Programming language Organometallic Complex Synthesis and Catalysis ; Supramolecular Chemistry and Complexes ; Polyoxometalates: Synthesis and Applications
Authors: Deeb Taher | Sami Klaib | Firas F. Awwadi | Wissam Helal | Mohammed Gharaibeh | G. Rheinwald | Tobias Rüffer | Heinrich Lang
Source: Inorganica Chimica Acta (article, 2018-03-21)
Field: Chemistry — Organic Chemistry

Ti(ƞ5-1-SiMe3-C9H6)(Cl)2(OR): Structure and bonding Chemistry ; Benzene ; Crystallography ; Yield (engineering) ; Ion ; Solid-state ; Crystal structure ; Density functional theory ; Electron density ; Computational chemistry ; Electron ; Physical chemistry ; Organic chemistry ; Thermodynamics Organometallic Complex Synthesis and Catalysis ; Coordination Chemistry and Organometallics ; Synthesis and characterization of novel inorganic/organometallic compounds
Authors: Monica Enculescu | Alexandru Evanghelidis | Ionuţ Enculescu
Source: Polymers (article, 2018-07-04)
Field: Materials Science — Biomaterials

White-Light Emission of Dye-Doped Polymer Submicronic Fibers Produced by Electrospinning Lighting and display technologies are evolving at tremendous rates nowadays; new device architectures based on new, microscopic building blocks are being developed. Besides high light-emission efficiencies, qualities including low cost, low environmental impact, flexibility, or lightweightness are sought for developing new types of devices. Electrospun polymer fibers represent an interesting type of such microscopic structures that can be employed in developing new functionalities. White-light-emitting fiber mats were prepared by the electrospinning of different dye-doped polymer solutions. Two approaches were used in order to obtain white-light emissions: the overlapping of single-dye-doped electrospun fiber mats, and the electrospinning of mixtures of different ratios of single-dye-doped polymer solutions. Scanning electron microscopy (SEM) was used to investigate the morphologies of the electrospun fibers with diameters ranging between 300 nm and 1 µm. Optical absorption and photoluminescence (PL) were evaluated for single-dye-doped submicronic fiber mats, for overlapping mats, and for fiber mats obtained from different compositions of mixtures. Depending on the ratios of the mixtures of different dyes, the luminance was balanced between blue and red emissions. Commission Internationale de L'Eclairage (CIE) measurements depict this fine-tuning of the colors' intensities, and the right composition for white-light emission of the submicronic fiber mats was found. Electrospinning ; Materials science ; Polymer ; Photoluminescence ; Fiber ; Doping ; Optical fiber ; Nanofiber ; Scanning electron microscope ; White light ; Nanotechnology ; Chemical engineering ; Composite material ; Optoelectronics ; Optics Electrospun Nanofibers in Biomedical Applications ; Advanced Sensor and Energy Harvesting Materials ; Conducting polymers and applications
Authors: Botond Szilágyi | Andy Koswara | Bradley P. Loren | Christina R. Ferreira | David H. Thompson | Zoltán K. Nagy
Source: Chemical Engineering Science (article, 2018-10-28)
Field: Chemistry — Spectroscopy

Piezoelectric-based high performance spray solvent delivery system for desorption electrospray ionization mass spectrometry: Systematic design and case studies for high throughput screening of N-alkylation reactions Desorption electrospray ionization ; Chemistry ; Volumetric flow rate ; Solvent ; Reaction rate ; Desorption ; Process engineering ; Analytical Chemistry (journal) ; Nanotechnology ; Materials science ; Ionization ; Organic chemistry ; Ion ; Chemical ionization ; Catalysis ; Adsorption ; Thermodynamics Mass Spectrometry Techniques and Applications ; Microfluidic and Capillary Electrophoresis Applications ; Advanced Chemical Sensor Technologies
Authors: Priscila Destro | Daniel Augusto Cantaneo | Débora Motta Meira | Guilherme dos Santos Honório | Luelc Souza da Costa | J.M.C. Bueno | Daniela Zanchet
Source: European Journal of Inorganic Chemistry (article, 2018-06-13)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Formation of Bimetallic Copper–Gold Alloy Nanoparticles Probed by in Situ X‐ray Absorption Fine Structure Spectroscopy Advanced studies of the formation and growth processes of metal alloy nanoparticles are of great importance and provide a better understanding for the fine tuning of their properties for the desired applications. In this work, we followed the synthesis of Au 1– x Cu x colloidal nanoparticles by in situ time‐resolved X‐ray absorption fine structure (XAFS) spectroscopy. The particles were synthesized by a one‐pot approach with a homemade reactor adapted to the XAFS measurements. The colloidal nanoparticles were also characterized by complementary ex situ techniques. Analyses at the Cu‐ K edge and Au‐ L 3 edge confirmed that the initial reduction of the Au species occurs at low temperatures (&lt;100 °C) to form Au seeds that are subsequently enriched with Cu to form Au 0.75 Cu 0.25 alloy nanoparticles at 225 °C. An important finding was the temporary formation of a Cu 2 O‐type phase during the colloidal synthesis. This phase was consumed with the concomitant formation of the Au 1– x Cu x alloy nanoparticles. These results directly confirm the previous proposal that the alloy formation occurs through a digestive‐ripening‐like process of an amorphous Cu‐enriched phase. X-ray absorption fine structure ; Nanoparticle ; Alloy ; Bimetallic strip ; Chemistry ; Copper ; Absorption spectroscopy ; Absorption (acoustics) ; X-ray absorption spectroscopy ; Phase (matter) ; Amorphous solid ; Spectroscopy ; Chemical engineering ; Colloid ; Colloidal gold ; Extended X-ray absorption fine structure ; Metal ; Nanotechnology ; Crystallography ; Materials science ; Physical chemistry ; Composite material ; Organic chemistry ; Optics Gold and Silver Nanoparticles Synthesis and Applications ; Copper-based nanomaterials and applications ; nanoparticles nucleation surface interactions
Authors: Marwa A. A. Mohamed | H.M.A. Hussein | A. A.M. Ali
Source: Journal of Phytopathology and Pest Management (article, 2018-10-10)
Field: Materials Science — Materials Chemistry

Antifungal activity of different size controlled stable silver nanoparticles biosynthesized by the endophytic fungus Aspergillus terreus Silver nanoparticles (AgNPs) synthesized by using the aqueous extract of the endophytic fungus Aspergillus terreus F37 (KX024595) as reducing agent is reported here. The reaction medium employed in the synthesis process was optimized under a narrow range of pH and temperature to attain better yield, controlled size, and more stable of AgNPs. Further, the microbially synthesized AgNPs were studied through UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy analyses. The obtained results indicated the formation of high crystalline spherical AgNPs with an average diameter of 45.2±0.5 nm at room temperature (22 oC). Quantitative analyses indicated that reduction of the Ag+ precursor was promoted at elevated pH due to increased activity of biomolecules in the fungal extract. As a result, the size of the AgNPs decreased with increased pH of the reactions. The optimum conditions for maximum production of small control sized AgNPs (12± 0.5 nm) were pH (10) and temperature (100 oC). The outcomes of the antifungal activity of different controlled sized AgNPs showed their efficiently to inhibit the mycelial growth of the pathogenic fungus Alternaria solani, the causal agent of tomato early blight disease and reduced their viability in a pH and temperature dependent manner. These findings revealed that the fine tuning of the reaction synthesis parameters, will increase the chance to obtain desired well shaped and small sized AgNPs with potent antifungal activities, may have important applications as new bio-fungicides in controlling various plant diseases caused by fungi. Aspergillus terreus ; Silver nanoparticle ; Mycelium ; Nuclear chemistry ; Chemistry ; Fourier transform infrared spectroscopy ; Aspergillus fumigatus ; Transmission electron microscopy ; Alternaria solani ; Nanoparticle ; Fungicide ; Nanotechnology ; Materials science ; Botany ; Chemical engineering ; Food science ; Biology Nanoparticles: synthesis and applications