jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Amanda Binotto | Bruno Albuquerque de Castro | Vitor Vecina dos Santos | Jorge Alfredo Ardila‐Rey | André Luiz Andreoli
Source:  (article, 2020-11-14)
Field: Materials Science — Materials Chemistry

A Comparison between Piezoelectric Sensors Applied to Multiple Partial Discharge Detection by Advanced Signal Processing Analysis The development of sensors applied to failure detection systems for power transformers is a critical concern since this device stands out as a strategic component of the electric power system. Among the most common issues is the presence of partial discharges (PDs) in the insulation system of the transformer, which can lead the device to total failure. Aiming to prevent unexpected damages, several PD monitoring approaches have been developed. One of the most promising is the Acoustic Emission (AE) technique, which captures the acoustic signals generated by PDs using piezoelectric sensors. Although many studies have proved the effectiveness of AE, most signal processing approaches are strictly related to the frequency analysis of PD signals, which can hide important information such as the repetition rate of the failure. This article presents a comparison between two types of piezoelectric transducers: the microfiber composite (MFC) and the lead zirconate titanate (PZT). To ensure the detection of multiple PDs, time&ndash;frequency analysis was carried out by short-time Fourier transform (STFT). Intending to compare the sensibility of the transducers, the AE signals were windowed, and the root mean square (RMS) value was extracted for each part of the signal. The results indicate that spectrogram and RMS analysis have great potential to detect multiple PD activity. Although MFC was two times more sensitive to PD detection than the PZT sensor, PZT presents a higher frequency response band (0&ndash;100 kHz) than MFC (80 kHz). Spectrogram ; Partial discharge ; Acoustic emission ; Piezoelectricity ; Acoustics ; Piezoelectric sensor ; Materials science ; Signal processing ; Transducer ; Short-time Fourier transform ; Lead zirconate titanate ; Condition monitoring ; SIGNAL (programming language) ; Root mean square ; Electronic engineering ; Computer science ; Fourier analysis ; Fourier transform ; Voltage ; Electrical engineering ; Engineering ; Optoelectronics ; Digital signal processing ; Speech recognition ; Ferroelectricity ; Physics High voltage insulation and dielectric phenomena ; Power Transformer Diagnostics and Insulation ; Electrical Fault Detection and Protection
Authors: Simon R. Larsen | Leander Michels | Éverton Carvalho dos Santos | Marcella C. Berg | Will P. Gates | Laurie Aldridge | Tilo Seydel | Jacques Ollivier | Mark T. F. Telling | Jon Otto Fossum | Heloisa N. Bordallo
Source: Microporous and Mesoporous Materials (article, 2020-07-22)
Field: Materials Science — Biomaterials

Physicochemical characterisation of fluorohectorite: Water dynamics and nanocarrier properties Intercalation (chemistry) ; Nanocarriers ; Clay minerals ; Chemistry ; Chemical engineering ; Diffusion ; Thermal decomposition ; Chemical physics ; Materials science ; Mineralogy ; Thermodynamics ; Inorganic chemistry ; Drug delivery ; Organic chemistry Clay minerals and soil interactions ; Therapeutic Uses of Natural Elements ; Soil and Unsaturated Flow
Authors: Joshua Muir | Michael C. Jollands | Feiwu Zhang | Andrew Walker
Source: Physics and Chemistry of Minerals (article, 2020-11-24)
Field: Materials Science — Biomaterials

Explaining the dependence of M-site diffusion in forsterite on silica activity: a density functional theory approach Experimentally, silica activity (aSiO<sub>2</sub>) has been shown to have an effect on Mg diffusion in forsterite, but no fully satisfactory mechanism has yet been proposed. We calculated the effects of aSiO<sub>2</sub> and aluminium content (the main contaminant in some recent experimental studies), and their co-effect, on Mg diffusion in forsterite, using thermodynamic minimisations of defect formation energies [calculated using density functional theory (DFT)] and a Monte-Carlo diffusion model. These two variables, in isolation, do not appreciably change the defect concentrations of forsterite and thus do not affect the diffusivity of Mg. However, when elevated together, they cause large increases in the Mg vacancy content and thus can increase the Mg diffusivity by one to six orders of magnitude depending on temperature, with little pressure dependence. This effect is largely independent of Al<sub>2</sub>O<sub>3</sub> concentration above ~ 1 wt. ppm, and thus, for all practical purposes, should occur wherever forsterite is in the presence of enstatite. It is also largely dependent upon configurational entropy and is thus highly sensitive to the chemistry of the crystal. A low concentration of structurally bound hydroxyl groups at low temperatures (1000 K) suppresses this effect in pure forsterite, but it is likely robust in the presence of water either when alternative water sinks (such as Ti or Fe) are present, or at high temperatures (> 1500 K). This effect is also robust in the presence of ferrous iron (or other substitutional Mg defects) at all temperatures. Fe<sub>2</sub>O<sub>3</sub> can operate like Al<sub>2</sub>O<sub>3</sub> in this reaction and should enhance its effect. These findings explain the experimentally observed dependency of Mg diffusion of aSiO<sub>2</sub>, and elucidate how chemical activity variations in both experiments and natural settings could affect not only the diffusivity of Mg in forsterite, but of olivine-hosted cations in general. Forsterite ; Chemistry ; Thermal diffusivity ; Diffusion ; Enstatite ; Vacancy defect ; Thermodynamics ; Density functional theory ; Ferrous ; Mineralogy ; Crystallography ; Computational chemistry ; Meteorite ; Organic chemistry Clay minerals and soil interactions ; High-pressure geophysics and materials ; Geological and Geochemical Analysis
Authors: Michael R. Hudak | Ilya N. Bindeman
Source: Geochimica et Cosmochimica Acta (article, 2020-06-16)
Field: Materials Science — Ceramics and Composites

Solubility, diffusivity, and O isotope systematics of H2O in rhyolitic glass in hydrothermal temperature experiments Hydrothermal circulation ; Thermal diffusivity ; Rhyolite ; Solubility ; Systematics ; Isotope ; Mineralogy ; Geochemistry ; Geology ; Thermodynamics ; Chemistry ; Physical chemistry ; Nuclear physics ; Physics ; Volcanic rock ; Paleontology Glass properties and applications ; Geological and Geochemical Analysis ; Hydrocarbon exploration and reservoir analysis
Authors: Ghinwa Yaghy | Abdulraouf Ali | Thibaut Charpentier | Lorenzo Fusi | Anne Neville | David Harbottle
Source: Journal of Petroleum Science and Engineering (article, 2020-12-16)
Field: Chemistry — Analytical Chemistry

Wax deposition using a cold rotating finger: An empirical and theoretical assessment in thermally driven and sloughing regimes Sloughing ; Wax ; Mass transfer ; Thermal diffusivity ; Rotational speed ; Deposition (geology) ; Diffusion ; Chemistry ; Materials science ; Analytical Chemistry (journal) ; Mechanics ; Composite material ; Thermodynamics ; Chromatography ; Geology Petroleum Processing and Analysis ; Hydrocarbon exploration and reservoir analysis ; Enhanced Oil Recovery Techniques
Authors: Cynthia Cordt | Tobias Meckel | Andreas Geißler | Markus Biesalski
Source: Nanomaterials (article, 2020-12-07)
Field: Chemistry — Organic Chemistry

Entrapment of Hydrophobic Biocides into Cellulose Acetate Nanoparticles by Nanoprecipitation This contribution reports an efficient method for the production and use of biocide-loaded cellulose acetate nanoparticles. As well-known model biocides 4-Hexylresorcinol and Triclosan were used for in situ nanoparticle loading during a nanoprecipitation process. We show that the nanoparticle size can be well-controlled by variation of the cellulose acetate concentration during nanoprecipitation. Apart from strong evidence suggesting cellulose acetate particle formation according to a nucleation-aggregation mechanism, we further show that the biocide loading of the particles occurs by a diffusion process and not via co-precipitation. The quantity of particle loading was analyzed by <sup>1</sup>H-NMR spectroscopy of re-dissolved nanoparticles, and it was observed that a decisive factor for high packaging efficiency is the use of a biocide with low water solubility and high hydrophobicity. SEM studies showed no influence on the particle morphology or size by both biocides 4-Hexylresorcinol and Triclosan. Finally, an aqueous nanoparticle dispersion can be coated onto model paper sheets to yield pronounced antimicrobial surface-properties. Nanoparticles loaded with the biocide Triclosan showed a high antimicrobial activity against <i>Bacillus subtilis</i>, a cellulase producing bacteria, if applied to model paper substrates, even at extremely low coating weights of 1-5 g/m<sup>2</sup>, respectively. Additional long-term efficacy renders these nanoparticles ideal for various applications. Biocide ; Triclosan ; Nanoparticle ; Chemical engineering ; Cellulose acetate ; Cellulose ; Particle (ecology) ; Solubility ; Materials science ; Aqueous solution ; Particle size ; Silver nanoparticle ; Coating ; Chemistry ; Organic chemistry ; Nanotechnology Antimicrobial agents and applications ; Polydiacetylene-based materials and applications ; Biopolymer Synthesis and Applications
Authors: Lili Ren | Zhihui Yang | Lei Huang | Yingjie He | Haiying Wang | Liyuan Zhang
Source: Polymers (article, 2020-03-23)
Field: Materials Science — Biomaterials

Macroscopic Poly Schiff Base-Coated Bacteria Cellulose with High Adsorption Performance Here, a nanofiber-exfoliated bacteria cellulose aerogel with improved water affinity and high mass transfer was synthesized. Consequently, poly Schiff base can be uniformly coated within the body of bacteria cellulose aerogel without the traditional dispersion treatment. The composite aerogel has adequate mechanical and thermal stability and high mass transfer efficiency. Such an aerogel can serve as a superior adsorbent for flow through adsorption of pollution. Typically, the adsorption capacity towards Cr(VI), Cu(II), Re(VII), Conga red, and Orange G reaches as high as 321.5, 256.4, 153.8, 333.3, and 370.3 mg g<sup>-1</sup>, respectively. Moreover, the adsorption by this composite aerogel is very fast, such that, for example, at just 2 s, the adsorption is almost finished with Cr(VI) adsorption. Moreover, the composite aerogel exhibits a good adsorption-desorption capability. This research will hopefully shed light on the preparation of bacteria cellulose-derived macroscopic materials powerful in not only environmental areas, but also other related applications. Schiff base ; Cellulose ; Adsorption ; Bacterial cellulose ; Materials science ; Chemical engineering ; Bacteria ; Polymer chemistry ; Chemistry ; Organic chemistry ; Biology Advanced Cellulose Research Studies ; Electrospun Nanofibers in Biomedical Applications ; Hydrogels: synthesis, properties, applications
Authors: Rafaela Q. C. Melo | Marcus Vinícius Lia Fook | Antônio Gilson Barbosa de Lima
Source: Polymers (article, 2020-10-27)
Field: Materials Science — Polymers and Plastics

Non-Fickian Moisture Transport in Vegetable-Fiber-Reinforced Polymer Composites Using a Langmuir-Type Model The purpose of this article was to theoretically study the non-Fickian moisture absorption process in vegetable-fiber-reinforced polymer composites using a Langmuir-type model. Here, the focus was on evaluating the effect of the water layer thickness that surrounds the composite during the water migration process. The solutions of the governing equations were obtained using the finite volume method, considering constant thermophysical properties and non-deformable material. The results for the local and average moisture content and concentration, gradient values, and the transient rates of the free and bound (water) molecules in the process were presented and analyzed. It was observed that the water layer thickness strongly influenced the water absorption kinetics, the moisture content gradient values, and the equilibrium moisture content inside the material. It is envisaged that this new approach will contribute to better interpretation of experimental data and a better understanding of the physical phenomenon of water absorption, which directly affects the properties of composite materials. Materials science ; Composite material ; Moisture ; Water content ; Absorption of water ; Composite number ; Polymer ; Absorption (acoustics) ; Fiber ; Langmuir ; Bound water ; Volume (thermodynamics) ; Thermodynamics ; Molecule ; Chemistry ; Adsorption ; Organic chemistry ; Geotechnical engineering Natural Fiber Reinforced Composites ; Textile materials and evaluations ; Acoustic Wave Phenomena Research
Authors: Vazrik Chiloyan | Samuel Huberman | A. A. Maznev | Keith A. Nelson | Gang Chen
Source: Applied Physics Letters (article, 2020-04-20)
Field: Materials Science — Materials Chemistry

Thermal transport exceeding bulk heat conduction due to nonthermal micro/nanoscale phonon populations While classical size effects usually lead to a reduced effective thermal conductivity, we report here that nonthermal phonon populations produced by a micro/nanoscale heat source can lead to enhanced heat conduction, exceeding the prediction from Fourier's law. We study nondiffusive thermal transport by phonons at small distances within the framework of the Boltzmann transport equation (BTE) and demonstrate that the transport is significantly affected by the distribution of phonons emitted by the source. We discuss analytical solutions of the steady-state BTE for a source with a sinusoidal spatial profile, as well as for a three-dimensional Gaussian “hot spot,” and provide numerical results for single crystal silicon at room temperature. If a micro/nanoscale heat source produces a thermal phonon distribution, it gets hotter than that predicted by the heat diffusion equation; however, if the source predominantly produces low-frequency acoustic phonons with long mean free paths, it may get significantly cooler than that predicted by the heat equation, yielding an enhanced heat transport beyond bulk heat conduction. Thermal conduction ; Boltzmann equation ; Thermal conductivity ; Phonon ; Heat equation ; Materials science ; Heat current ; Condensed matter physics ; Physics ; Thermodynamics ; Composite material Thermal properties of materials ; Thermal Radiation and Cooling Technologies ; Advanced Thermoelectric Materials and Devices
Authors: Roman Lesyk
Source: Journal of Medical Science (article, 2020-06-26)
Field: Chemistry — Organic Chemistry

Drug design: 4-thiazolidinones applications. Part 2. Pharmacological profiles Following of the chemical diversity of 4-thiazolidinones the in-house library of new heterocycles have been designed and synthesized (more 7000 compounds). Anticancer, antitrypanosomal, antituberculosis and antiviral activity screening led to SAR database formation; lead-compounds identification; design of focused sub-libraries; formation and validation of hypotheses for structure optimization: i) complications of C5 fragment and/or functionalization of N3 position; ii) creation of the hybrid molecules; iii) fixation of 5-ene-4-thiazolidinones in fused heterocycles via annulation (thiopyrano[2,3-d]thiazoles were found as a cyclic isosteric mimetics of 5-ene-4-thiazolidinones); iv) the leukemia panel was detected to be the most sensitive among all cancer cell lines. Following the in silico and pharmacological data for the investigation of molecular mechanism of anticancer effect the argument in favor of the apoptotic related and mild prooxidant actions for active compounds have been found. Combinatorial chemistry ; In silico ; Chemistry ; Drug ; Drug discovery ; Lead compound ; Stereochemistry ; Computational biology ; Pharmacology ; Biochemistry ; Biology ; In vitro Synthesis and biological activity ; Synthesis and Characterization of Heterocyclic Compounds ; Synthesis and Reactivity of Sulfur-Containing Compounds
Authors: Łukasz Popiołek | Monika Gawrońska‐Grzywacz | Anna Berecka | Kinga Paruch | Iwona Piątkowska‐Chmiel | Dorota Natorska‐Chomicka | Mariola Herbet | Anna Gumieniczek | Jarosław Dudka | Monika Wujec
Source: Oncology Letters (article, 2020-09-02)
Field: Chemistry — Organic Chemistry

New benzenesulphonohydrazide derivatives as potential antitumour agents Cancer treatment remains a serious challenge worldwide. Thus, finding novel antitumour agents is of great importance. In the present study, nine new benzenesulphonohydrazide derivatives (1-9) were synthesized, and the chemical structures of the obtained compounds were confirmed by spectral analysis methods, including IR, <sup>1</sup>H nuclear magnetic resonance (NMR) and <sup>13</sup>C NMR. Experimental lipophilicity values were established using reversed phase-high performance thin layer chromatography. The antiproliferative activity of the synthesized compounds was tested against three tumour cell lines (769-P, HepG2 and NCI-H2170) and one normal cell line (Vero). Among the newly developed molecules, compound 4 exhibited generally the highest cytotoxicity across all tumour cell lines, and it was highly selective. However, higher selectivity towards the tested cancer cell lines was observed using compound 2, when compared with compound 4, which also exhibited significant antiproliferative activity against these tumour cells. In 769-P cells, compounds 5 and 6 were the most selective among all tested compounds. Compound 5 exhibited high cytotoxicity with an estimated IC<sub>50</sub> value of 1.94 µM. In the NCI-H2170 cell line, compound 7 was the most cytotoxic and the most selective. In brief, the combination of fluorine and bromine substituents at the phenyl ring showed the most promising results, exerting high cytotoxicity and selectivity towards cancer cells. The renal adenocarcinoma cell line (769-P) appeared to be the most sensitive to the anticancer properties of the novel benzenesulphonohydrazones. Cytotoxicity ; Lipophilicity ; Chemistry ; Cell culture ; Stereochemistry ; Cell cycle ; Apoptosis ; In vitro ; Biochemistry ; Biology Synthesis and biological activity ; Enzyme function and inhibition ; Metal complexes synthesis and properties
Authors: А. М. Попов | А. А. Климович | Olga Styshova | Т. В. Московкина | Andrey E. Shchekotikhin | Natalia E. Grammatikova | Lyubov G. Dezhenkova | Dmitry N. Kaluzhny | Peter Deriabin | А.В. Герасименко | А.А. Удовенко | Valentin A. Stonik
Source: International Journal of Molecular Medicine (article, 2020-08-06)
Field: Chemistry — Organic Chemistry

Design, synthesis and biomedical evaluation of mostotrin, a new water soluble tryptanthrin derivative Mostotrin (MT), a novel compound, at least five orders of magnitude more soluble in water than its mother substance, was designed and synthesised from tryptanthrin (TR). Its structure was established by nuclear magnetic resonance and mass spectrometry data and confirmed by X‑ray analysis, revealing that MT is a pentacyclic product with an additional pseudo‑cycle formed with the participation of one intramolecular hydrogen bond. Antimicrobial activity and cytotoxic action against tumour cells in vitro, as well as anti‑tumour effects, acute toxicity and anti‑inflammatory activities in vivo, were evaluated. Antimicrobial properties of MT against Mycobacterium spp and Bacillus cereus ATCC 10702 appeared to be the same as that of TR, but against the other strains used it was weaker. Furthermore, MT exhibited 5‑10 times higher cytotoxic activities against tumour cell lines HCT‑116, МСF‑7 and K‑562 than TR, but was less toxic than TR (LD50 of MT was 375 mg/kg, while LD50 for TR was 75 mg/kg). Additionally, compounds MT and TR were studied in DNA binding tests. The quenching of its fluorescence on addition to DNA solution established MT to be capable of binding to DNA. Its anti‑tumour action in vivo on mice with the ascitic form of Ehrlich carcinoma was promising, particularly with joint application of MT and the antitumour drug doxorubicin. In this model, the survival and life span for the doxorubicin and 1 co‑treatment group were significantly higher compared to doxorubicin treatment alone. The compound MT showed a lower immunosuppressive effect than TR at the early stages of inflammation induced in mice by LPS from E. сoli (MT hardly inhibited the release of IL‑1, IL‑2, or INF‑γ). These results demonstrated that MT is a perspective hit compound for drug development. In our opinion, further evaluation on the biological effects of MT and its synthetic analogues could lead to safer and more effective anti‑tumour and anti‑tuberculosis agents than TR itself. MT has also the prospect of application in combination with known anti‑tumour drugs for the treatment of oncological diseases. Derivative (finance) ; Cell cycle ; Oncogene ; Combinatorial chemistry ; Molecular medicine ; Chemistry ; Apoptosis ; Biochemistry Quinazolinone synthesis and applications ; Synthesis and Biological Evaluation ; Cancer therapeutics and mechanisms
Authors: Adam I. Green | Fruzsina Hóbor | Christopher P. Tinworth | Stuart L. Warriner | Andrew J. Wilson | Adam Nelson
Source: Chemistry - A European Journal (article, 2020-05-27)
Field: Chemistry — Organic Chemistry

Activity‐Directed Synthesis of Inhibitors of the p53/<i>h</i>DM2 Protein–Protein Interaction Protein-protein interactions (PPIs) provide a rich source of potential targets for drug discovery and biomedical science research. However, the identification of structural-diverse starting points for discovery of PPI inhibitors remains a significant challenge. Activity-directed synthesis (ADS), a function-driven discovery approach, was harnessed in the discovery of the p53/hDM2 PPI. Over two rounds of ADS, 346 microscale reactions were performed, with prioritisation on the basis of the activity of the resulting product mixtures. Four distinct and novel series of PPI inhibitors were discovered that, through biophysical characterisation, were shown to have promising ligand efficiencies. It was thus shown that ADS can facilitate ligand discovery for a target that does not have a defined small-molecule binding site, and can provide distinctive starting points for the discovery of PPI inhibitors. Drug discovery ; Computational biology ; Small molecule ; Function (biology) ; Identification (biology) ; Ligand (biochemistry) ; Protein–protein interaction ; Protein function ; Ligand efficiency ; Chemistry ; Combinatorial chemistry ; Biology ; Biochemistry ; Cell biology ; Receptor ; Gene Click Chemistry and Applications ; Catalytic C–H Functionalization Methods ; Cyclopropane Reaction Mechanisms