jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Isabela Sales | Dinis O. Abranches | Pedro Costa | Tânia E. Sintra | Sónia P. M. Ventura | Silvana Mattedi | João A. P. Coutinho | Mara G. Freire | Simão P. Pinho
Source: Fluid Phase Equilibria (article, 2021-01-19)
Field: Materials Science — Materials Chemistry

Enhancing Artemisinin Solubility in Aqueous Solutions: Searching for Hydrotropes based on Ionic Liquids Chemistry ; Solubility ; Ionic liquid ; Artemisinin ; Aqueous solution ; Dicyanamide ; Solvent ; Organic chemistry ; Phosphonium ; Hydrogen peroxide ; Catalysis Crystallization and Solubility Studies ; Ionic liquids properties and applications ; Analytical Chemistry and Chromatography
Authors: Minglun Li | Bilin Zhuang | Jing Yu
Source: Macromolecules (article, 2021-10-06)
Field: Materials Science — Surfaces, Coatings and Films

Sequence–Conformation Relationship of Zwitterionic Peptide Brushes: Theories and Simulations Zwitterionic polymer brushes have broad applications in antifouling, biolubrication, and drug delivery. The charge distribution on polymers is critical to the structure and properties of surface-tethered zwitterionic polymer brushes. However, there is a lack of understanding of the relationship between the charge distribution and conformation in these systems, which is important for designing and predicting the functionality of controllable surface-tethered polymer brushes. Zwitterionic peptides with different sequences of charged amino acids are excellent model systems to elucidate such a charge–conformation relationship. By performing all-atom molecular dynamics (MD) simulations and developing a discrete-charge mean-field theory, we perform a systematic investigation on the effect of charge distribution on the conformations of zwitterionic peptide brushes. All-atom MD simulations reveal that the height of the peptide brush strongly depends on the distribution of the charges along the peptide chain. Contact map analysis reveals that the charge sequence also determines the preferred intrachain (loops and extended) and interchain (head-to-tail and parallel) structures. Through the theory developed by us, we show that the interchain electrostatic interactions are responsible for the contraction of peptide brushes with long charged blocks, while elasticity drives the contraction of peptide brushes with alternating-charged segments. This study provides a clear illustration of the factors influencing the sequence–conformation relationship of zwitterionic peptide brushes. Peptide ; Polymer ; Molecular dynamics ; Chemical physics ; Polymer brush ; Chemistry ; Sequence (biology) ; Static electricity ; Surface charge ; Electrostatics ; Charge (physics) ; Crystallography ; Materials science ; Computational chemistry ; Physics ; Physical chemistry ; Organic chemistry ; Polymerization Polymer Surface Interaction Studies ; Force Microscopy Techniques and Applications ; Dendrimers and Hyperbranched Polymers
Authors: P. V. Melnikov | A. Yu. Alexandrovskaya | Alina O. Naumova | Nadezhda Popova | Б. В. Спицын | Н. К. Зайцев | N. A. Yashtulov
Source: Nanomaterials (article, 2021-11-06)
Field: Materials Science — Materials Chemistry

Modified Nanodiamonds as a Means of Polymer Surface Functionalization. From Fouling Suppression to Biosensor Design The development of different methods for tuning surface properties is currently of great interest. The presented work is devoted to the use of modified nanodiamonds to control the wetting and biological fouling of polymers using optical sensors as an example. We have shown that, depending on the type of modification and the amount of nanodiamonds, the surface of the same fluorinated polymer can have both bactericidal properties and, on the contrary, good adhesion to the biomaterial. The precise control of wetting and biofouling properties of the surface was achieved by the optimization of the modified nanodiamonds thermal anchoring conditions. In vitro and in vivo tests have shown that the fixation of amine functional groups leads to inhibition of biological activity, while the presence of a large number of polar groups of mixed composition (amide and acid chloride) promotes adhesion of the biomaterial and allows one to create a biosensor on-site. A comprehensive study made it possible to establish that in the first 5 days the observed biosensor response is provided by cells adhered to the surface due to the cell wall interaction. On the 7th day, the cells are fixed by means of the polysaccharide matrix, which provides much better retention on the surface and a noticeably greater response to substrate injections. Nevertheless, it is important to note that even 1.5 h of incubation is sufficient for the formation of the reliable bioreceptor on the surface with the modified nanodiamonds. The approach demonstrated in this work makes it possible to easily and quickly isolate the microbiome on the surface of the sensor and perform the necessary studies of its substrate specificity or resistance to toxic effects. Biosensor ; Wetting ; Surface modification ; Biomaterial ; Polymer ; Fouling ; Materials science ; Biofouling ; Nanodiamond ; Adhesion ; Nanotechnology ; Chemical engineering ; Contact angle ; Biocompatibility ; Chemistry ; Composite material ; Membrane Diamond and Carbon-based Materials Research ; Analytical chemistry methods development ; Carbon Nanotubes in Composites
Authors: Michael B. Farrar | Helen M. Wallace | Peter Brooks | Catherine M. Yule | Iman Tahmasbian | Peter K. Dunn | Shahla Hosseini Bai
Source: Remote Sensing (article, 2021-05-06)
Field: Chemistry — Analytical Chemistry

A Performance Evaluation of Vis/NIR Hyperspectral Imaging to Predict Curcumin Concentration in Fresh Turmeric Rhizomes Hyperspectral image (HSI) analysis has the potential to estimate organic compounds in plants and foods. Curcumin is an important compound used to treat a range of medical conditions. Therefore, a method to rapidly determine rhizomes with high curcumin content on-farm would be of significant advantage for farmers. Curcumin content of rhizomes varies within, and between varieties but current chemical analysis methods are expensive and time consuming. This study compared curcumin in three turmeric (Curcuma longa) varieties and examined the potential for laboratory-based HSI to rapidly predict curcumin using the visible–near infrared (400–1000 nm) spectrum. Hyperspectral images (n = 152) of the fresh rhizome outer-skin and flesh were captured, using three local varieties (yellow, orange, and red). Distribution of curcuminoids and total curcumin was analysed. Partial least squares regression (PLSR) models were developed to predict total curcumin concentrations. Total curcumin and the proportion of three curcuminoids differed significantly among all varieties. Red turmeric had the highest total curcumin concentration (0.83 ± 0.21%) compared with orange (0.37 ± 0.12%) and yellow (0.02 ± 0.02%). PLSR models predicted curcumin using raw spectra of rhizome flesh and pooled data for all three varieties (R2c = 0.83, R2p = 0.55, ratio of prediction to deviation (RPD) = 1.51) and was slightly improved by using images of a single variety (orange) only (R2c = 0.85, R2p = 0.62, RPD = 1.65). However, prediction of curcumin using outer-skin of rhizomes was poor (R2c = 0.64, R2p = 0.37, RPD = 1.28). These models can discriminate between ‘low’ and ‘high’ values and so may be adapted into a two-level grading system. HSI has the potential to help identify turmeric rhizomes with high curcumin concentrations and allow for more efficient refinement into curcumin for medicinal purposes. Curcumin ; Rhizome ; Curcuma ; Orange (colour) ; Hyperspectral imaging ; Partial least squares regression ; Chemistry ; Mathematics ; Horticulture ; Food science ; Botany ; Biology ; Statistics ; Remote sensing Spectroscopy and Chemometric Analyses ; Essential Oils and Antimicrobial Activity ; Phytochemicals and Antioxidant Activities
Authors: Dan Peng | Yali Liu | Jiasheng Yang | Yanlan Bi | Jingnan Chen
Source: Journal of Spectroscopy (article, 2021-06-16)
Field: Chemistry — Analytical Chemistry

Nondestructive Detection of Moisture Content in Walnut Kernel by Near-Infrared Diffuse Reflectance Spectroscopy The rapid and accurate detection of the moisture content is of great significance to the quality evaluation and oil extraction process of walnut kernel. Near-infrared (NIR) spectroscopy is an ideal method for measuring the moisture content in walnut kernel. In this study, a regression model for moisture content in walnut kernel was developed based on NIR diffuse reflectance spectroscopy using chemometric methods. The different spectral pretreatment methods were adopted to preprocess the original spectral data. The whole spectra band was divided into 5 subbands, 10 subbands, 15 subbands, and 20 subbands to screen specific wavelengths relevant to the walnut kernel moisture content. PLS (partial least square regression), MLR (multivariate linear regression), PCR (principle component regression), and SVR (support vector regression) were used to establish the relationship model between the spectral data and measurement values of the moisture content. In comparison, the optimized modeling conditions were determined as follows: detection wavelength 1349–1490 nm, SNV-FD (standard normal variate transformation and first derivative) preprocessing method, and PLS algorithm. Under these conditions, the square correlation coefficient (R2) and root mean square error of prediction (RMSEP) of the prediction model were 0.9865 and 0.0017, respectively. The results of this study provided a feasible method for the rapid detection of moisture content in walnut kernel. To improve the performance and applicability of the model, it is necessary to continuously expand the size of the sample set. Near-infrared spectroscopy ; Mathematics ; Kernel (algebra) ; Water content ; Principal component regression ; Mean squared error ; Linear regression ; Principal component analysis ; Correlation coefficient ; Moisture ; Partial least squares regression ; Coefficient of determination ; Statistics ; Chemistry ; Optics ; Physics Spectroscopy and Chemometric Analyses ; Nuts composition and effects ; Phytochemicals and Antioxidant Activities
Authors: Marco Dalla Tiezza | Trevor A. Hamlin | F. Matthias Bickelhaupt | Laura Orian
Source: ChemMedChem (article, 2021-09-18)
Field: Chemistry — Organic Chemistry

Radical Scavenging Potential of the Phenothiazine Scaffold: A Computational Analysis The reactivity of phenothiazine (PS), phenoselenazine (PSE), and phenotellurazine (PTE) with different reactive oxygen species (ROS) has been studied using density functional theory (DFT) in combination with the QM-ORSA (Quantum Mechanics-based Test for Overall Free Radical Scavenging Activity) protocol for an accurate kinetic rate calculation. Four radical scavenging mechanisms have been screened, namely hydrogen atom transfer (HAT), radical adduct formation (RAF), single electron transfer (SET), and the direct oxidation of the chalcogen atom. The chosen ROS are HO<sup>.</sup> , HOO<sup>.</sup> , and CH<sub>3</sub> OO<sup>.</sup> . PS, PSE, and PTE exhibit an excellent antioxidant activity in water regardless of the ROS due to their characteristic diffusion-controlled regime processes. For the HO<sup>.</sup> radical, the primary active reaction mechanism is, for all antioxidants, RAF. But, for HOO<sup>.</sup> and CH<sub>3</sub> OO<sup>.</sup> , the dominant mechanism strongly depends on the antioxidant: HAT for PS and PSE, and SET for PTE. The scavenging efficiency decreases dramatically in lipid environment and remains only significant (via RAF) for the most reactive radical (HO<sup>.</sup> ). Therefore, PS, PSE, and PTE are excellent antioxidant molecules, especially in aqueous, physiological environments where they are active against a broad spectrum of harmful radicals. There is no advantage or significant difference in the scavenging efficiency when changing the chalcogen since the reactivity mainly derives from the amino hydrogen and the aromatic sites. Phenothiazine ; Scavenging ; Chemistry ; Scaffold ; Combinatorial chemistry ; Computer science ; Pharmacology ; Biochemistry ; Biology ; Antioxidant Free Radicals and Antioxidants ; Photochemistry and Electron Transfer Studies ; Phenothiazines and Benzothiazines Synthesis and Activities
Authors: Yingying Li | Jingfeng Huang
Source: Sensors (article, 2021-04-28)
Field: Chemistry — Analytical Chemistry

Leaf Anthocyanin Content Retrieval with Partial Least Squares and Gaussian Process Regression from Spectral Reflectance Data Leaf pigment content retrieval is an essential research field in remote sensing. However, retrieval studies on anthocyanins are quite rare compared to those on chlorophylls and carotenoids. Given the critical physiological significance of anthocyanins, this situation should be improved. In this study, using the reflectance, partial least squares regression (PLSR) and Gaussian process regression (GPR) were sought to retrieve the leaf anthocyanin content. To our knowledge, this is the first time that PLSR and GPR have been employed in such studies. The results showed that, based on the logarithmic transformation of the reflectance (log(1/<i>R</i>)) with 564 and 705 nm, the GPR model performed the best (R<sup>2</sup>/RMSE (nmol/cm<sup>2</sup>): 0.93/2.18 in the calibration, and 0.93/2.20 in the validation) of all the investigated methods. The PLSR model involved four wavelengths and achieved relatively low accuracy (R<sup>2</sup>/RMSE (nmol/cm<sup>2</sup>): 0.87/2.88 in calibration, and 0.88/2.89 in validation). GPR apparently outperformed PLSR. The reason was likely that the non-linear property made GPR more effective than the linear PLSR in characterizing the relationship for the absorbance vs. content of anthocyanins. For GPR, selected wavelengths around the green peak and red edge region (one from each) were promising to build simple and accurate two-wavelength models with R<sup>2</sup> > 0.90. Partial least squares regression ; Calibration ; Content (measure theory) ; Remote sensing ; Anthocyanin ; Kriging ; Absorbance ; Linear regression ; Chemometrics ; Mathematics ; Chemistry ; Food science ; Statistics ; Chromatography ; Geography Spectroscopy and Chemometric Analyses ; Remote Sensing in Agriculture ; Leaf Properties and Growth Measurement
Authors: Mohana SundaramK | Priyanka Prakash | S. Angalaeswari | T. Deepa | L. Natrayan | Prabhu Paramasivam
Source: Journal of Nanomaterials (article, 2021-12-15)
Field: Materials Science — Materials Chemistry

Influence of Process Parameter on Carbon Nanotube Field Effect Transistor Using Response Surface Methodology Carbon nanotube field-effect transistor (CNTFET) is a good option to replace silicon for low power consumption application. Recent research shows that CN-FET thermal and electrical properties alter with length, diameter, and gate parameters. Optimization of CNTFET design parameters helps control some of the factors. Double gate and cylindrical gate layouts are introduced to overcome these facts. Carbon nanotubes have an intercapacitance between them that increases as their diameter increases. Total capacitance and inductance of CNTFETs increase with nanotube count. In order to reduce the voltage drop between semiconducting and metallic terminals, the diameter and pitch must be raised. This study employs response surface methodology and ANOVA technique that were used to optimize CNTFET process parameters. Thickness, voltage, delay, and power were all considered. The most affecting parameter was investigated. Materials science ; Carbon nanotube field-effect transistor ; Carbon nanotube ; Transistor ; Field-effect transistor ; Capacitance ; Voltage ; Response surface methodology ; Optoelectronics ; Inductance ; Nanotechnology ; Electrical engineering ; Computer science ; Electrode Carbon Nanotubes in Composites ; Nanotechnology research and applications ; Integrated Circuits and Semiconductor Failure Analysis
Authors: Yosuke Harashima | Keiichi Tamai | Shotaro Doi | Munehisa Matsumoto | Hisazumi Akai | Naoki Kawashima | Masaaki Ito | Noritsugu Sakuma | Akira Kato | Tetsuya Shoji | Takashi Miyake
Source: Physical Review Materials (article, 2021-01-26)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Data assimilation method for experimental and first-principles data: Finite-temperature magnetization of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>Nd</mml:mi><mml:mo>,</mml:mo><mml:mi>Pr</mml:mi><mml:mo>,</mml:mo><mml:mi>La</mml:mi><mml:mo>,</mml:mo><mml:mi>Ce</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>Fe</mml:mi><mml:mo>,</mml:mo><mml:mi>Co</mml:mi><mml:mo>,</mml:mo><mml:mi>Ni</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>14</mml:mn></mml:msub><mml:mi mathvariant="normal">B</mml:mi></mml:mrow></mml:math> We propose a data assimilation method for evaluating the finite-temperature magnetization of a permanent magnet over a high-dimensional composition space. Based on a general framework for constructing a predictor from two data sets including missing values, a practical scheme for magnetic materials is formulated in which a small number of experimental data in limited composition space are integrated with a larger number of first-principles calculation data. We apply the scheme to ${({\mathrm{Nd}}_{1\ensuremath{-}\ensuremath{\alpha}\ensuremath{-}\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}}{\mathrm{Pr}}_{\ensuremath{\alpha}}{\mathrm{La}}_{\ensuremath{\beta}}{\mathrm{Ce}}_{\ensuremath{\gamma}})}_{2}{({\mathrm{Fe}}_{1\ensuremath{-}\ensuremath{\delta}\ensuremath{-}\ensuremath{\zeta}}{\mathrm{Co}}_{\ensuremath{\delta}}{\mathrm{Ni}}_{\ensuremath{\zeta}})}_{14}\mathrm{B}$. The magnetization in the whole $(\ensuremath{\alpha},\ensuremath{\beta},\ensuremath{\gamma},\ensuremath{\delta},\ensuremath{\zeta})$ space at arbitrary temperature is obtained. It is shown that the Co doping does not enhance the magnetization at low temperatures, whereas the magnetization increases with increasing $\ensuremath{\delta}$ above 320 K. Magnetization ; Magnet ; Space (punctuation) ; Experimental data ; Doping ; Assimilation (phonology) Magnetic Properties of Alloys ; Rare-earth and actinide compounds ; Magnetic and transport properties of perovskites and related materials
Authors: Kaiji Chen | Xueqian Zhang | Xieyu Chen | Tong Wu | Qing-Wei Wang | Ziying Zhang | Quan Xu | Jiaguang Han | Weili Zhang
Source: IEEE photonics journal (article, 2021-01-29)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Active Dielectric Metasurfaces for Switchable Terahertz Beam Steering and Focusing Conventional metasurfaces often manipulate light propagation in a passive way, which cannot satisfy the dynamic operation requirements of many practical applications. Integrating functional materials or components into the structure design is one effective method, which, however, often introduces additional loss to the resonances, thus greatly affecting the efficiency of modulation. Here, we numerically propose a reflection-type dielectric metasurface design that could allow switchable and efficient wavefront control in the terahertz regime. The metasurfaces are composed of dielectric structures suspended on a ground metallic film, which can exhibit different phase responses at different gap distances between them owing to the variation of the Fabre-Pérot (FP) resonance. Two metasurfaces are designed and numerically demonstrated, which can achieve mechanically switchable beam steering and wave focusing responses, respectively, by only changing the gap distance by a small range of 1/3 working wavelength. The maximum efficiency can reach around 89%. The proposed method provides a new avenue towards efficient and active terahertz wavefront control. Terahertz radiation ; Wavefront ; Beam steering ; Dielectric ; Optics ; Materials science ; Reflection (computer programming) ; Optoelectronics ; Beam (structure) ; Wavelength ; Phase (matter) ; Computer science ; Physics Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Plasmonic and Surface Plasmon Research
Authors: Abdelmjeed Mohamed | Saeed Salehi | Ramadan Ahmed | Guoqiang Li
Source: Journal of Petroleum Science and Engineering (article, 2021-09-24)
Field: Materials Science — Polymers and Plastics

Experimental study on rheological and settling properties of shape memory polymer for fracture sealing in geothermal formations Rheology ; Materials science ; Settling ; Volumetric flow rate ; Drilling fluid ; Particle (ecology) ; Drill pipe ; Rotational speed ; Geothermal gradient ; Shear thinning ; Composite material ; Geotechnical engineering ; Drill ; Drilling ; Geology ; Mechanics ; Mechanical engineering ; Engineering ; Metallurgy Polymer composites and self-healing ; Grouting, Rheology, and Soil Mechanics ; Fluid Dynamics Simulations and Interactions
Authors: Haikuan Dong | Petri Hirvonen | Zheyong Fan | Ping Qian | Yanjing Su | Tapio Ala-Nissilä
Source: Journal of Applied Physics (article, 2021-12-15)
Field: Materials Science — Materials Chemistry

Heat transport across graphene/hexagonal-BN tilted grain boundaries from phase-field crystal model and molecular dynamics simulations We study the interfacial thermal conductance of grain boundaries (GBs) between monolayer graphene and hexagonal boron nitride (h-BN) sheets using a combined atomistic approach. First, realistic samples containing graphene/h-BN GBs with different tilt angles are generated using the phase-field crystal model developed recently [P. Hirvonen et al., Phys. Rev. B 100, 165412 (2019)] that captures slow diffusive relaxation inaccessible to molecular dynamics (MD) simulations. Then, large-scale MD simulations using the efficient GPUMD package are performed to assess heat transport and rectification properties across the GBs. We find that lattice mismatch between the graphene and h-BN sheets plays a less important role in determining the interfacial thermal conductance as compared to the tilt angle. In addition, we find no significant thermal rectification effects for these GBs. Graphene ; Grain boundary ; Molecular dynamics ; Materials science ; Condensed matter physics ; Boron nitride ; Crystal (programming language) ; Relaxation (psychology) ; Monolayer ; Nanotechnology ; Composite material ; Chemistry ; Computational chemistry ; Microstructure ; Physics Thermal properties of materials ; Advanced Thermoelectric Materials and Devices ; nanoparticles nucleation surface interactions