jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Juliana Lorenz Mandro Campiol | Nathália Torres Corrêa Magri | Juliana Aparecida de Souza Sartori | Felipe Iwagaki Braga Ogando | Cláudio Lima de Aguiar
Source: Brazilian journal of food technology/Brazilian Journal of Food Technology (article, 2019-01-01)
Field: Chemistry — Analytical Chemistry

Color reduction of raw sugar syrup using hydrogen peroxide Abstract A commercial H2O2 solution (35%, v/v) was evaluated as a clarifying agent for raw, type VHP (very high polarization) sugar syrup, using an experimental design applying artificial neural networks (ANN). Fifteen experimental runs were carried out and the samples were taken at the following time intervals: 0, 5, 10, 15, 20, 25, 30, 40, 50, 60, 75 and 90 min. The treatments were carried out using an experimental design consisting of three variables: H2O2 (X1: 0; 202.4; 500; 797.6 and 1.000 mg L-1); pH (X2: 3.32, 5, 7.5, 10 and 11.68) and temperature (X3: 16.4, 30, 50, 70 and 83.6°C). The theoretical and measured values fitted the analysis by artificial neural networks (ANN) well. A reduction in colour (ICUMSA method) was observed between 60 and 75 min, except for treatments # 11 (pH= 11.68; 50°C and 500 mgH2O2 L-1), # 13 (pH=7.5; 83.6°C and 500 mgH2O2 L-1) and #15 (pH= 7.5; 50°C and 1.000 mgH2O2 L-1), which showed a colour reduction after 30 min. In the treatments at pH 3.32 or 11.68, temperature of 83.6°C and H2O2 dose of 1.000 mg L-1, an average sucrose degradation of 55% was observed. The best colour reduction result was obtained with treatment # 9 (pH 7.5, 50 °C and 500 mgH2O2 L-1), although sucrose degradation of 26% was observed. Chemistry ; Hydrogen peroxide ; Sugar ; Sucrose ; Chromatography ; Raw material ; Nuclear chemistry ; Food science ; Biochemistry ; Organic chemistry Dye analysis and toxicity ; Biochemical Analysis and Sensing Techniques ; Natural Products and Biological Research
Authors: Loghman Zareei | Baharak Divband | Asghar Mesbahi | M. Khatamian | Anita Kiani | Nahideh Gharehaghaji
Source: Journal of Biomedical Physics and Engineering (article, 2019-04-06)
Field: Materials Science — Biomaterials

A New Potential Contrast Agent for Magnetic Resonance Imaging: Iron Oxide-4A Nanocomposite The high T2/T1 relaxivity ratio of the iron oxide-4A nanocomposite confirms it's potential to act as a T2 contrast agent. Nanocomposite ; Magnetic resonance imaging ; Materials science ; Relaxation (psychology) ; Iron oxide ; MRI contrast agent ; Contrast (vision) ; Oxide ; Nuclear magnetic resonance ; Nanoparticle ; Nanotechnology ; Radiology ; Medicine ; Computer science Nanoparticle-Based Drug Delivery ; Characterization and Applications of Magnetic Nanoparticles ; Graphene and Nanomaterials Applications
Authors: Olli-Pekka Koistinen | Vilhjálmur Ásgeirsson | Aki Vehtari | Hannes Jónsson
Source: ChemRxiv (preprint, 2019-10-21)
Field: Materials Science — Materials Chemistry

Minimum Mode Saddle Point Searches Using Gaussian Process Regression with Inverse-Distance Covariance Function The minimum mode following method can be used to find saddle points on an energy surface by following a direction guided by the lowest curvature mode. Such calculations are often started close to a minimum on the energy surface to find out which transitions can occur from an initial state of the system, but it is also common to start from the vicinity of a first order saddle point making use of an initial guess based on intuition or more approximate calculations. In systems where accurate evaluations of the energy and its gradient are computationally intensive, it is important to exploit the information of the previous evaluations to enhance the performance. Here, we show that the number of evaluations required for convergence to the saddle point can be significantly reduced by making use of an approximate energy surface obtained by a Gaussian process model based on inverse inter-atomic distances, evaluating accurate energy and gradient at the saddle point of the approximate surface and then correcting the model based on the new information. The performance of the method is tested with start points chosen randomly in the vicinity of saddle points for dissociative adsorption of an H2 molecule on the Cu(110) Surface and three gas phase chemical reactions. Saddle point ; Inverse ; Saddle ; Covariance ; Curvature ; Mathematics ; Gaussian process ; Gaussian curvature ; Maxima and minima ; Gaussian ; Mathematical optimization ; Mathematical analysis ; Physics ; Geometry ; Statistics ; Quantum mechanics Machine Learning in Materials Science ; Gaussian Processes and Bayesian Inference ; Advanced Multi-Objective Optimization Algorithms
Authors: Ilya Kuprov
Source: Journal of Magnetic Resonance (article, 2019-07-09)
Field: Chemistry — Spectroscopy

Defeating the Matrix Hindsight bias ; Notation ; Computer science ; Scaling ; Software ; Code (set theory) ; Field (mathematics) ; Matrix (chemical analysis) ; Artificial intelligence ; Computational science ; Arithmetic ; Psychology ; Programming language ; Mathematics ; Cognitive psychology Advanced NMR Techniques and Applications ; Electron Spin Resonance Studies ; NMR spectroscopy and applications
Authors: M. G. Danikas | S. Morsalin
Source: Engineering Technology & Applied Science Research (review, 2019-10-09)
Field: Materials Science — Materials Chemistry

Foreign Inclusions, Enclosed Cavities, Partial Discharge Models and Discharge Energy: A Short Review Regarding Solid Dielectrics and Composite Insulating Systems Partial discharges in cavities are one of the main reasons of breakdown of insulating materials and insulating systems in general. The present paper aims at commenting some aspects of the relation between partial discharges and insulation damage. Some basic models explaining the workings and impacts of discharges in cavities are discussed. Discussions about the possibility of damage in the presence of multiple cavities as well as of the risks of minute discharges and/or charging phenomena below the so-called inception voltage are conducted. It is remarked that the question of the relationship between discharge parameters and insulation damage is still an important one, especially for composite insulating systems. Partial discharge ; Composite number ; Dielectric ; Materials science ; Insulation system ; Electrical treeing ; Voltage ; Mechanics ; Engineering physics ; Composite material ; Electrical engineering ; Forensic engineering ; Physics ; Engineering ; Optoelectronics High voltage insulation and dielectric phenomena ; Power Transformer Diagnostics and Insulation ; Lightning and Electromagnetic Phenomena
Authors: Yuta Otsuka | Akira Ito | Tōru Takahashi | Saki Matsumura | Masaki Takeuchi | Hideji Tanaka
Source: Chemical and Pharmaceutical Bulletin (article, 2019-03-31)
Field: Chemistry — Analytical Chemistry

Bilayer Tablet Dissolution Kinetics Based on a Degassing Cyclic Flow UV-Vis Spectroscopy with Chemometrics Dissolution kinetics of a bilayer direct compress tablet was evaluated by using degassing cyclic flow UV-visible (Vis) spectroscopy with chemometrics. The model bilayer nicotinamide (NA)-pyridoxine hydrochloride (PH) 100.0 mg tablets were prepared via the dual compress method. The fast diffusion layer of the bilayer tablet contained nicotinamide, microcrystal cellulose, beta-lactose, magnesium stearate, and croscarmellose sodium. The slow release layer contained pyridoxine hydrochloride and carnauba wax. The monolayer direct compress tablets were prepared as dual ingredient (API)s formulation tablets. The degassing cyclic flow UV-Vis spectroscopy dissolution test was carried out using the prepared tablets. The dissolution test conditions were as follows: time, 60 min; temperature, 37°C; paddle method, 50 rpm, and UV-Vis spectra measurement 1 time/min. The UV-Vis spectra of the flow solution were measured in the range of 240-380 nm. API concentration was predicted by partial least squares (PLS) regression models based on UV-Vis spectra. The dissolution kinetics of the bilayer and monolayer tablets were evaluated based on the UV-Vis spectra with the predicted API concentration profile. The degassing flow system could prevent air bubbles in the flow cell at 1800 min. Therefore, simultaneous determination of NA and PH concentration based on the PLS regression was suggested to have high accuracy. PLS regression has advantages over the conventional λ<sub>max</sub> absorbance method of simultaneous determination. We found that the kinetics of the separated bilayer tablet can be evaluated by the same kinetic analysis method used for the single layer model tablet. Chemistry ; Magnesium stearate ; Bilayer ; Dissolution ; Analytical Chemistry (journal) ; Absorbance ; Chromatography ; Chemometrics ; Ultraviolet visible spectroscopy ; Kinetics ; Dosage form ; Organic chemistry Spectroscopy and Chemometric Analyses ; Drug Solubulity and Delivery Systems ; Analytical Methods in Pharmaceuticals
Authors: Mohamed Osman Elfaki | Mukhtaar Qaaed S. Sultan | Inas Osman Khojali Mohammed
Source: Computational Chemistry (article, 2019-11-21)
Field: Chemistry — Organic Chemistry

Mechanistic Study of Anticancer Activity of Some Known Aminopyrimidoisoquinolinequinones via QSAR Classification Methodology The impact of lipophilicity as represented by the logarithm of octanol/water partition coefficient (logP), the combined steric/polarizability effect as represented by molar refractivity (MR) and bulk as represented by molar volume (MV) on the biological activity of 29 known aminopyrimidoisoquinolinequinones APIQ were analyzed using quantitative structure activity relationships methodology (QSAR). The activity data chosen was the inhibitory concentration (IC50) against human gastric adenocarcinoma (AGS) cell line. On running regression analysis, the physicochemical parameters and IC50 show very weak correlations as evident by the low values of Pearson Correlation R2 (0.1 to 0.2). Since the individual compounds show appreciable activity (ranging from 20 to 0.5 μM), classification was resorted to in order to expose mechanistic nesting subgroups. This was done by clustering data points around various trend lines extracted from the scattered plot relating parameters to activity using R2 as an index. The correlation of IC50 versus MV was chosen a base of classification owing to higher statistical metrics it yield. This gave five regression lines, each of which is believed to represent a separate mechanistic profile. Additional descriptors were used to consolidate the clustering approach and to give depth to the assumed mechanistic profiles of each cluster. Quantitative structure–activity relationship ; Molar refractivity ; Lipophilicity ; Partition coefficient ; Chemistry ; Polarizability ; Correlation coefficient ; Octanol ; Logarithm ; Regression analysis ; Linear regression ; Cluster analysis ; Pearson product-moment correlation coefficient ; Molecular descriptor ; Mathematics ; Regression ; Biological system ; Statistics ; Stereochemistry ; Chromatography ; Molecule ; Organic chemistry Synthesis and biological activity ; Free Radicals and Antioxidants ; Chemical synthesis and pharmacological studies
Authors: Veikko Sajaniemi | Alp Karakoç | Jouni Paltakari
Source: Research on Engineering Structures and Materials (article, 2019-01-01)
Field: Materials Science — Polymers and Plastics

Mechanical and thermal behavior of natural fiber-polymer composites without compatibilizers The present study aims at understanding the mechanical and thermal properties of natural fibers in a polymer matrix without strong adhesion between the two constitutes. For this purpose, four types of pulps, which are refined and unrefined pine and birch kraft pulps, were used together with polypropylene without any compatibilizer. One constituent pulp based and composite pulp fiber-polypropylene handsheets were prepared by standard laboratory sheet preparation method followed by hot pressing process. In addition to these handsheets, pure polypropylene sheets were also formed as the reference. The produced handsheets were tested to determine their tensile properties following the ISO 1924-2 standard for paper and board. During these tests, infrared thermal imaging was also carried out with FLIR A655SC thermal camera with frame rate of 200 Hz and thermal resolution of 50 mK so as to investigate the thermal behavior. As a result of the experiments, it was deduced that the chosen methods produced composites with unsatisfactory properties. In addition, microstructures of the investigated handsheets were analyzed with scanning electron microscopy (SEM) indicating the heterogeneous mixing of constituents and existence of material defects, which was mainly due to the inherent incompatibility of hydrophilic natural fibers and hydrophobic thermoplastics. Composite material ; Materials science ; Thermal ; Fiber ; Natural fiber ; Polymer Natural Fiber Reinforced Composites ; Material Properties and Applications
Authors: Huihui He | Weiying Lu
Source: Sensors (article, 2019-09-26)
Field: Chemistry — Analytical Chemistry

High-Throughput Chemometric Quality Assessment of Extra Virgin Olive Oils Using a Microtiter Plate Reader A commercially available microtiter plate reader was applied as a high-throughput counterpart of ultraviolet-visible (UV–Vis) spectrophotometer to identify the producing location of extra virgin olive oils (EVOOs). Multiplicative scatter correction and the first derivative was used to denoise the UV–Vis spectra and eliminate the effects of background drift. The spectra were analyzed using chemometrics methods including the principal component analysis (PCA) and the partial least squares-discriminant analysis (PLS-DA). The PLS-DA model on full spectra using 5 latent variables showed a classification accuracy of 97.92% by cross-validation. The overall results demonstrated that the use of a UV–Vis spectrophotometer based on the microtiter plate reader combined with chemometrics can be applied to the quality assessment of EVOOs. It is demonstrated that the microtiter plate reader can be a high-throughput tool in the quality assessment of food ingredients. Chemometrics ; Microtiter plate ; Partial least squares regression ; Principal component analysis ; Chromatography ; Chemistry ; Linear discriminant analysis ; Biological system ; Analytical Chemistry (journal) ; Plate reader ; Pattern recognition (psychology) ; Artificial intelligence ; Mathematics ; Computer science ; Statistics ; Optics ; Fluorescence ; Biology Spectroscopy and Chemometric Analyses ; Edible Oils Quality and Analysis ; Advanced Chemical Sensor Technologies
Authors: E.V. Popov | Anatoly Batiukov | N. Vogt | T.P. Popova | J. Vogt
Source:  (article, 2019-07-16)
Field: Chemistry — Physical and Theoretical Chemistry

VISUALIZATION AND ANALYSIS OF MOLECULAR POTENTIAL ENERGY SURFACE (PES) AND ITS MINIMA The study of the potential energy surface (PES) of a molecule is of fundamental importance in structural chemistry. PES,being a function of torsion angles describing the internal rotation of different fragments in the molecule, is Maxima and minima ; Visualization ; Potential energy surface ; Molecule ; Surface (topology) ; Internal rotation ; Potential energy ; Torsion (gastropod) ; Chemical physics ; Computational chemistry ; Computer science ; Physics ; Chemistry ; Classical mechanics ; Data mining ; Mathematics ; Geometry ; Engineering ; Quantum mechanics ; Mechanical engineering ; Biology Various Chemistry Research Topics ; Advanced Physical and Chemical Molecular Interactions
Authors: Güzide PEKCAN ERTOKUŞ
Source: International Journal of Analytical Chemistry (article, 2019-07-09)
Field: Chemistry — Analytical Chemistry

The Determination of Parkinson’s Drugs in Human Urine by Applying Chemometric Methods The spectrophotometric-chemometric analysis of levodopa and carbidopa that are used for Parkinson's disease was analyzed without any prior reservation. Parkinson's drugs in the urine sample of a healthy person (never used drugs in his life) were analyzed at the same time spectrophotometrically. The chemometric methods used were partial least squares regression (PLS) and principal component regression (PCR). PLS and PCR were successfully applied as chemometric determination of levodopa and carbidopa in human urine samples. A concentration set including binary mixtures of levodopa and carbidopa in 15 different combinations was randomly prepared in acetate buffer (pH 3.5).). UV spectrophotometry is a relatively inexpensive, reliable, and less time-consuming method. Minitab program was used for absorbance and concentration values. The normalization values for each active substance were good (r2>0.9997). Additionally, experimental data were validated statistically. The results of the analyses of the results revealed high recoveries and low standard deviations. Hence, the results encouraged us to apply the method to drug analysis. The proposed methods are highly sensitive and precise, and therefore they were implemented for the determination of the active substances in the urine sample of a healthy person in triumph. Carbidopa ; Chromatography ; Partial least squares regression ; Urine ; Principal component regression ; Chemistry ; Absorbance ; Levodopa ; Principal component analysis ; Parkinson's disease ; Mathematics ; Medicine ; Internal medicine ; Statistics ; Biochemistry Analytical Methods in Pharmaceuticals ; Electrochemical sensors and biosensors ; Electrochemical Analysis and Applications
Authors: Sk Manirul Haque | Murad Alsawalha
Source: International Journal of Applied Pharmaceutics (article, 2019-03-28)
Field: Chemistry — Analytical Chemistry

ANALYTICAL METHODS FOR THE QUANTITATION OF AMLODIPINE BESYLATE AND ATORVASTATIN CALCIUM IN PHARMACEUTICAL DOSAGE FORM AND BIOLOGICAL FLUIDS Amlodipine is the best-prescribed medication for cardiovascular disease major risk factor for hypertension and atorvastatin well known for diabetic. First discussed low cost ultraviolet-visible technique for the determination and quantitation of drugs in pharmaceuticals and biological fluids. Chromatographic techniques have an application with respect to trace analysis. Different types of chromatography such as high-performance liquid chromatography, high performance thin layer chromatography have most frequent applications in the field of pharmaceutical as well as biomedical analyses. Chromatography combined with mass spectrophotometry has the ability to collect molecular ion, followed to prepare a spectrum to assess molecular weight as well as structure. High-performance liquid chromatography coupled with mass spectrophotometry is a reliable and dynamic technique for the analysis of small and large drugs molecule. The advantages and disadvantages of all techniques are compared with each other with respect to sensitivity, reproducibility and other important parameters. The investigation also focused for the quantitation on both drugs in pharmaceutical preparations and plasma samples with the help of all available analytical techniques. Amlodipine ; Chromatography ; Chemistry ; Dosage form ; High-performance liquid chromatography ; Spectrophotometry ; Biological fluids ; High performance thin layer chromatography ; Thin-layer chromatography ; Pharmaceutical formulation ; Medicine Analytical Methods in Pharmaceuticals ; Analytical Chemistry and Chromatography ; Pharmacological Effects and Assays
Authors: Lakshmi Prasanna Lingamdinne | Jong-Soo Choi | Yu-Lim Choi | Jae‐Kyu Yang | Janardhan Reddy Koduru | Yoon‐Young Chang
Source: Metals (article, 2019-08-27)
Field: Chemistry — Inorganic Chemistry

Green Activated Magnetic Graphitic Carbon Oxide and Its Application for Hazardous Water Pollutants Removal Graphitic carbon oxide (GCO) and magnetic graphitic carbon oxide (MGCO) were prepared from sugar via optimized green activation by employing ozone oxidation, and applied to wastewater treatment. The maximal oxidation and adsorption yield of pollutants were achieved at pH 2.0−4.0, which is the optimized pH for ozone oxidation of GC to generate GCO. As-prepared GCO and MGCO were characterized using X-ray, infrared, and microscopic techniques. The MGCO has enough saturation magnetization (MS) of 41.38 emu g−1 for separation of the sorbent from the reaction medium by applying an external magnetic field. Batch adsorption of radioactive and heavy metals (Th(IV), Pb(II)), and a dye (methylene blue (MB)) using GCO and MGCO was evaluated by varying the adsorbent dose, equilibrium pH, contact time, initial metal and dye concentrations, and kinetics and isotherms. Adsorption kinetics and isotherm studies indicated that Th(IV), Pb(II), and MB adsorption were best described by pseudo-second-order kinetics and Langmuir isotherm with R2 (correlation coefficient) &gt; 0.99, respectively. The maximum adsorption capacities for Th(IV), Pb(II), and MB were 52.63, 47.39, and 111.12 mg g−1 on GCO and 76.02, 71.94, and 76.92 mg g−1 on MGCO. GCO and MGCO are prospectively effective and low-cost adsorbents for ion removal in wastewater treatment. As prepared MGCO can be reused up to three cycles for Th(IV), Pb(II), and MB. This work provides fundamental information about the equilibrium adsorption isotherms and mechanisms for Th(IV), Pb(II), and MB on GCO and MGCO. Adsorption ; Chemistry ; Activated carbon ; Sorbent ; Kinetics ; Langmuir adsorption model ; Oxide ; Inorganic chemistry ; Nuclear chemistry ; Organic chemistry Radioactive element chemistry and processing ; Adsorption and biosorption for pollutant removal ; Geochemistry and Elemental Analysis