jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Dantio Nguela Christian Brice | Ngomo Horace Manga | Bénédoué Serge Arnold | Kouotou Daouda | Abega Aimé Victoire | Ndongo Ndongo Alain Giresse | Che Randy Nangah | Ndi Julius Nsami
Source: Open Journal of Inorganic Chemistry (article, 2021-01-01)
Field: Chemistry — Analytical Chemistry

Adsorption of Tartrazine onto Activated Carbon Based Cola Nuts Shells: Equilibrium, Kinetics, and Thermodynamics Studies The uptake of tartrazine from its aqueous solution by powdered activated carbon prepared from cola nut shells chemically activated with potassium hydroxide (ACK) and phosphoric acid (ACP) has been investigated using kinetics models. Batch isotherm data were analysed with the pseudo-first order, pseudo-second order model as well as the intraparticle diffusion model. For structural elucidation, the materials were characterized using FTIR, XRD and SEM. These analyses revealed that the activated carbons (ACK and ACP) were predominantly mesoporous with several oxygen-containing functional groups dispersed on their surface. The reaction was systematically investigated under various experimental conditions such as contact time, adsorbent dose and pH. For the two adsorbents, the quantity adsorbed of 19.256 mg/g and 18.196 mg/g respectively for ACP and ACK at respective contact times of 5 and 10 min were obtained. The adsorption data were tested with the Langmuir, Freundlich models. Langmuir model was found to best describe the adsorption of tartrate ions with maximum monolayer adsorption capacities of 24.57 and 21.59 mg/g for ACP and ACK, respectively. Results analysis indicated clearly that the pseudo-second order kinetic rate model best fitted the experimental data and therefore was the adsorption controlling mechanism for both adsorbents. Thermodynamic studies revealed that the adsorption process was spontaneous and exothermic for ACP with increased randomness at the solid solution interface, then exothermic but non-spontaneous for ACK. The results show that these activated carbons could be an alternative for more costly adsorbents for the purpose of tartrate ions elimination. Adsorption ; Chemistry ; Freundlich equation ; Tartrazine ; Langmuir ; Activated carbon ; Potassium hydroxide ; Phosphoric acid ; Inorganic chemistry ; Ion exchange ; Aqueous solution ; Langmuir adsorption model ; Kinetics ; Organic chemistry ; Chromatography ; Ion Dye analysis and toxicity ; Adsorption and biosorption for pollutant removal ; Electrochemical sensors and biosensors
Authors: J. Luis López‐Miranda | Gustavo A. Molina | Rodrigo Esparza | Marlén Alexis González-Reyna | Rodolfo Silva | Miriam Estévez
Source: Toxics (article, 2021-10-28)
Field: Materials Science — Materials Chemistry

Green Synthesis of Homogeneous Gold Nanoparticles Using Sargassum spp. Extracts and Their Enhanced Catalytic Activity for Organic Dyes <i>Sargassum</i> species-based extracts were used to carry out the synthesis of homogeneous gold nanoparticles. Various techniques were used to determine the characteristics and composition of the nanoparticles. The UV-Vis results showed that the 50% water/ethanol extract had the most reducing agents and stabilizers. Therefore, this type of extract was used to synthesize nanoparticles and for their subsequent characterization. Crystallinity and crystal size were evaluated using X-ray diffraction. Size and morphology were analyzed using scanning electron microscopy, showing that the gold nanoparticles were mostly spherical, with a size range of 15-30 nm. The catalytic activity of the gold nanoparticles was evaluated through the degradation of organic dyes: methylene blue, methyl orange, and methyl red. The degradation rates were different, depending on the nature of each dye, the simplest to degrade was methylene blue and methyl red was the most difficult to degrade. The results indicated that the use of <i>Sargassum</i> spp. for the synthesis of gold nanoparticles has potential in the remediation of water that is contaminated with organic dyes. Moreover, given the recent serious environmental and economic problems caused by the overpopulation of <i>Sargassum</i> spp. in the Mexican Caribbean, the findings hold promise for their practical and sustainable use in the synthesis of nanomaterials. Methyl orange ; Methylene blue ; Colloidal gold ; Nanomaterials ; Nanoparticle ; Sargassum ; Catalysis ; Nanomaterial-based catalyst ; Nuclear chemistry ; Crystallinity ; Chemistry ; Oxidizing agent ; Materials science ; Organic chemistry ; Nanotechnology ; Algae ; Photocatalysis ; Botany Nanoparticles: synthesis and applications
Authors: Yongqiang Wang | Zhuo Zeng | Meng Gao | Ziye Huang
Source: Polymers (article, 2021-06-29)
Field: Materials Science — Materials Chemistry

Hygrothermal Aging Characteristics of Silicone-Modified Aging-Resistant Epoxy Resin Insulating Material To study the improvement effect of silicone materials on the hygrothermal resistance of epoxy resin and the aging mechanism of silicone-modified insulation materials under hygrothermal conditions, diphenylsilanediol was added to epoxy resin as a modifier in various quantities to synthesize silicone-modified epoxy resin, and a hygrothermal aging test was carried out. Water sorption, surface contact angles and dielectric properties of the insulation material were measured, and scanning electron microscope (SEM), Fourier-transform infrared spectrometry (FT-IR) and frequency domain spectroscopy (FDS) were used to analyze the results. The results showed that under 10 wt%, the silicone-modified insulation materials exhibited lower absorption rate and better dielectric properties, including lower dissipation factors and lower dielectric constant during the hygrothermal aging process, while epoxy resin modified with excessive silicone material tend to show worse dielectric performance. Closer analysis found that diphenylsilanediol decreases the size of the cracks within the material during hygrothermal aging, indicating that cracks generated during the hygrothermal aging process may be the reason for the worse dielectric performance, and diphenylsilanediol improves the hygrothermal aging resistance mainly by slowing down the generation and growth rate of cracks. FT-IR results confirmed the existence of hydrolysis and found that the rate of hydrolysis does not change with the content of diphenylsilanediol. FDS results also indicated that modified materials contain less dipoles after hygrothermal aging. Materials science ; Epoxy ; Composite material ; Silicone ; Dielectric ; Scanning electron microscope ; Fourier transform infrared spectroscopy ; Silicone resin ; Accelerated aging ; Absorption of water ; Chemical engineering High voltage insulation and dielectric phenomena ; Corrosion Behavior and Inhibition ; Silicone and Siloxane Chemistry
Authors: Tahira Yaqoob | Malika Rani | Arshad Mahmood | Rubia Shafique | Safia Khan | Naveed Kausar Janjua | Aqeel Ahmad Shah | Awais Ahmad | Abdullah A. Al‐Kahtani
Source: Materials (article, 2021-10-12)
Field: Materials Science — Materials Chemistry

MXene/Ag2CrO4 Nanocomposite as Supercapacitors Electrode MXene/Ag<sub>2</sub>CrO<sub>4</sub> nanocomposite was synthesized effectively by means of superficial low-cost co-precipitation technique in order to inspect its capacitive storage potential for supercapacitors. MXene was etched from MAX powder and Ag<sub>2</sub>CrO<sub>4</sub> spinel was synthesized by an easy sol-gel scheme. X-Ray diffraction (XRD) revealed an addition in inter-planar spacing from 4.7 Å to 6.2 Å while Ag<sub>2</sub>CrO<sub>4</sub> nanoparticles diffused in form of clusters over MXene layers that had been explored by scanning electron microscopy (SEM). Energy dispersive X-Ray (EDX) demonstrated the elemental analysis. Raman spectroscopy opens the gap between bonding structure of as-synthesized nanocomposite. From photoluminence (PL) spectra the energy band gap value 3.86 eV was estimated. Electrode properties were characterized by applying electrochemical observations such as cyclic voltammetry along with electrochemical impedance spectroscopy (EIS) for understanding redox mechanism and electron transfer rate constant K<sub>app</sub>. Additionally, this novel work will be an assessment to analyze the capacitive behavior of electrode in different electrolytes such as in acidic of 0.1 M H<sub>2</sub>SO<sub>4</sub> has specific capacitance C<sub>sp</sub> = 525 F/g at 10 mVs<sup>-1</sup> and much low value in basic of 1 M KOH electrolyte. This paper reflects the novel synthesis and applications of MXene/Ag<sub>2</sub>CrO<sub>4</sub> nanocomposite electrode fabrication in energy storage devices such as supercapacitors. Supercapacitor ; Cyclic voltammetry ; Materials science ; Dielectric spectroscopy ; Nanocomposite ; Scanning electron microscope ; Electrode ; Electrolyte ; Nanoporous ; Capacitance ; Chemical engineering ; Raman spectroscopy ; Energy-dispersive X-ray spectroscopy ; Nanotechnology ; Electrochemistry ; Analytical Chemistry (journal) ; Composite material ; Chemistry ; Organic chemistry ; Optics MXene and MAX Phase Materials ; Supercapacitor Materials and Fabrication ; Advanced Memory and Neural Computing
Authors: Henry Chu | Stephen Garoff | Robert D. Tilton | Aditya S. Khair
Source: Journal of Fluid Mechanics (article, 2021-04-30)
Field: Chemistry — Physical and Theoretical Chemistry

Macrotransport theory for diffusiophoretic colloids and chemotactic microorganisms Abstract Microorganism ; Chemotaxis ; Materials science ; Mechanics ; Physics ; Bacteria ; Medicine ; Geology Electrostatics and Colloid Interactions ; Microfluidic and Bio-sensing Technologies ; Nanopore and Nanochannel Transport Studies
Authors: Mark Winter | Miri Morgulis | Tsvia Gildor | Andrew R. Cohen | Smadar Ben‐Tabou de‐Leon
Source: PLoS Computational Biology (article, 2021-02-22)
Field: Materials Science — Biomaterials

Calcium-vesicles perform active diffusion in the sea urchin embryo during larval biomineralization Biomineralization is the process by which organisms use minerals to harden their tissues and provide them with physical support. Biomineralizing cells concentrate the mineral in vesicles that they secret into a dedicated compartment where crystallization occurs. The dynamics of vesicle motion and the molecular mechanisms that control it, are not well understood. Sea urchin larval skeletogenesis provides an excellent platform for investigating the kinetics of mineral-bearing vesicles. Here we used lattice light-sheet microscopy to study the three-dimensional (3D) dynamics of calcium-bearing vesicles in the cells of normal sea urchin embryos and of embryos where skeletogenesis is blocked through the inhibition of Vascular Endothelial Growth Factor Receptor (VEGFR). We developed computational tools for displaying 3D-volumetric movies and for automatically quantifying vesicle dynamics. Our findings imply that calcium vesicles perform an active diffusion motion in both, calcifying (skeletogenic) and non-calcifying (ectodermal) cells of the embryo. The diffusion coefficient and vesicle speed are larger in the mesenchymal skeletogenic cells compared to the epithelial ectodermal cells. These differences are possibly due to the distinct mechanical properties of the two tissues, demonstrated by the enhanced f-actin accumulation and myosinII activity in the ectodermal cells compared to the skeletogenic cells. Vesicle motion is not directed toward the biomineralization compartment, but the vesicles slow down when they approach it, and probably bind for mineral deposition. VEGFR inhibition leads to an increase of vesicle volume but hardly changes vesicle kinetics and doesn't affect f-actin accumulation and myosinII activity. Thus, calcium vesicles perform an active diffusion motion in the cells of the sea urchin embryo, with diffusion length and speed that inversely correlate with the strength of the actomyosin network. Overall, our studies provide an unprecedented view of calcium vesicle 3D-dynamics and point toward cytoskeleton remodeling as an important effector of the motion of mineral-bearing vesicles. Biomineralization ; Sea urchin ; Calcium ; Embryo ; Vesicle ; Larva ; Biology ; Cell biology ; Developmental biology ; Biophysics ; Anatomy ; Chemistry ; Ecology ; Biochemistry ; Membrane ; Astrobiology Calcium Carbonate Crystallization and Inhibition ; Marine Biology and Environmental Chemistry ; Physiological and biochemical adaptations
Authors: Eduardo P. Milan | Murilo Álison Vigilato Rodrigues | Virgínia da Conceição Amaro Martins | Ana Maria de Guzzi Plepis | Thomas Fuhrmann‐Lieker | Marilia M. Horn
Source: Molecules (article, 2021-05-13)
Field: Materials Science — Biomaterials

Mineralization of Phosphorylated Fish Skin Collagen/Mangosteen Scaffolds as Potential Materials for Bone Tissue Regeneration In this study, a potential hard tissue substitute was mimicked using collagen/mangosteen porous scaffolds. Collagen was extracted from Tilapia fish skin and mangosteen from the waste peel of the respective fruit. Sodium trimetaphosphate was used for the phosphorylation of these scaffolds to improve the nucleation sites for the mineralization process. Phosphate groups were incorporated in the collagen structure as confirmed by their attenuated total reflection Fourier transform infrared (ATR-FTIR) bands. The phosphorylation and mangosteen addition increased the thermal stability of the collagen triple helix structure, as demonstrated by differential scanning calorimetry (DSC) and thermogravimetry (TGA) characterizations. Mineralization was successfully achieved, and the presence of calcium phosphate was visualized by scanning electron microscopy (SEM). Nevertheless, the porous structure was maintained, which is an essential characteristic for the desired application. The deposited mineral was amorphous calcium phosphate, as confirmed by energy dispersive X-ray spectroscopy (EDX) results. Differential scanning calorimetry ; Mineralization (soil science) ; Fourier transform infrared spectroscopy ; Chemistry ; Apatite ; Attenuated total reflection ; Von Kossa stain ; Scanning electron microscope ; Thermal stability ; Calcium ; Phosphate ; Biomaterial ; Thermogravimetry ; Chemical engineering ; Nuclear chemistry ; Materials science ; Infrared spectroscopy ; Biophysics ; Biochemistry ; Mineralogy ; Organic chemistry ; Inorganic chemistry ; Alkaline phosphatase ; Composite material Collagen: Extraction and Characterization ; Bone Tissue Engineering Materials ; biodegradable polymer synthesis and properties
Authors: Mohamed S. Nafie | Ahmed I. Khodair | Hebat Allah Y. Hassan | Noha M. Abd El‐Fadeal | Hanin A. Bogari | Sameh S. Elhady | Safwat A. Ahmed
Source: Molecules (article, 2021-12-23)
Field: Chemistry — Organic Chemistry

Evaluation of 2-Thioxoimadazolidin-4-one Derivatives as Potent Anti-Cancer Agents through Apoptosis Induction and Antioxidant Activation: In Vitro and In Vivo Approaches Hepatocellular carcinoma (HCC) is one of the most widespread malignancies and is reported as the fourth most prevalent cause of cancer deaths worldwide. Therefore, we aimed to investigate the probable mechanistic cytotoxic effect of the promising 2-thioxoimidazolidin-4-one derivative on liver cancer cells using in vitro and in vivo approaches. The compounds were tested for the in vitro cytotoxic activity using MTT assay, and the promising compound was tested in colony forming unit assay, flow cytometric analysis, RT-PCR, Western blotting, in vivo using SEC-carcinoma and in silico to highlight the virtual mechanism of action. Both compounds <b>4</b> and <b>2</b> performed cytotoxic effects against HepG2 cells with IC<sub>50</sub> values of 0.017 and 0.18 μM, respectively, compared to Staurosporine and 5-Fu as reference drugs with IC<sub>50</sub> values of 5.07 and 5.18 µM, respectively. Compound <b>4</b> treatment revealed apoptosis induction by 19.35-fold (11.42% compared to 0.59% in control), arresting the cell cycle at G2/M phase. Moreover, studying gene expression that plays critical roles in cell cycle and apoptosis by RT-PCR demonstrated that compound <b>4</b> enhances the expression of the pro-apoptotic genes p53, PUMA, and Caspase 3, 8, and 9, and impedes the anti-apoptotic Bcl-2 gene in the HepG2 cells. It can also inhibit the PI3K/AKT pathway at both gene and protein levels, which was reinforced by the in silico predictions of the molecular docking simulations towards the PI3K/AKT proteins. Finally, in vivo study verified that compound <b>4</b> has a promising anti-cancer activity through activating antioxidant levels (CAT, SOD and GSH) and ameliorating hematological, biochemical, and histopathological findings. In vivo ; Apoptosis ; PI3K/AKT/mTOR pathway ; Cytotoxic T cell ; Cell cycle ; Protein kinase B ; Cancer cell ; MTT assay ; In vitro ; Chemistry ; Biology ; Molecular biology ; Cancer research ; Cancer ; Biochemistry ; Genetics Synthesis and biological activity ; Synthesis and Characterization of Heterocyclic Compounds ; Synthesis of heterocyclic compounds
Authors: Giovanni Angiulli | Mario Versaci
Source: IEEE Access (article, 2021-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Retrieving the Effective Parameters of an Electromagnetic Metamaterial Using the Nicolson-Ross-Weir Method: An Analytic Continuation Problem Along the Path Determined by Scattering Parameters Electromagnetic metamaterials (MMs) are composite structures that allow one to potentially develop unique and innovative microwave, millimetre wave, and optical devices due to their unusual physical properties. In this process, their electromagnetic characterization plays a fundamental role. Various procedures have been proposed to accomplish this task, but the Nicolson-Ross-Weir (NRW) method still appears to be the most commonly adopted one even though it is afflicted by the severe issue of branch ambiguity. In this paper, we have demonstrated that rigorously, as the branch ambiguity can be entirely overcome through the analytic continuation of a specific analytic logarithm element along the path determined in the complex plane by the scattering parameters of an MM under analysis. Furthermore, the underlying relationship between analytic continuation, phase unwrapping approach, implemented through a procedure devised by Oppenheim and Schafer for the homomorphic treatment of signals (hereafter named PUNWOS), and the Kronig-Kramers relation has been discussed and enlightened, demonstrating the full equivalence among the methods. To clarify this aspect, a couple of numerical examples is presented. The results discussed in this study open the possibility of employing the vast theoretical equipment developed in the phase unwrapping field to achieve the retrieval of MMs' effective parameters when the NRW method is applicable. Continuation ; Analytic continuation ; Weir ; Metamaterial ; Scattering ; Path (computing) ; Physics ; Mathematical analysis ; Mathematics ; Computer science ; Optics Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Antenna Design and Analysis
Authors: Christian Winkler | Tomas Kamencek | Egbert Zojer
Source: Nanoscale (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Understanding the origin of serrated stacking motifs in planar two-dimensional covalent organic frameworks Covalent organic frameworks (COFs) have attracted significant attention due to their chemical versatility combined with a significant number of potential applications. Of particular interest are two-dimensional COFs, where the organic building units are linked by covalent bonds within a plane. Most properties of these COFs are determined by the relative arrangement of neighboring layers. These are typically found to be laterally displaced, which, for example, reduces the electronic coupling between the layers. In the present contribution we use dispersion-corrected density-functional theory to elucidate the origin of that displacement, showing that the common notion that the displacement is a consequence of electrostatic repulsions of polar building blocks can be misleading. For the representative case of COF-1 we find that electrostatic and van der Waals interactions would, actually, favor a cofacial arrangement of the layers and that Pauli repulsion is the crucial factor causing the serrated AA-stacking. A more in-depth analysis of the electrostatic contribution reveals that the "classical" Coulomb repulsion between the boroxine building blocks of COF-1 suggested by chemical intuition does exist, but is overcompensated by attractive effects due to charge-penetration in the phenylene units. The situation becomes more involved, when additionally allowing the interlayer distance to relax for each displacement, as then the different distance-dependences of the various types of interactions come into play. The overall behavior calculated for COF-1 is recovered for several additional COFs with differently sized π-systems and topologies, implying that the presented results are of more general relevance. Stacking ; Covalent bond ; Planar ; Pauli exclusion principle ; Materials science ; Chemical physics ; Crystallography ; Nanotechnology ; Chemistry ; Condensed matter physics ; Physics ; Computer science ; Organic chemistry Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Luminescence and Fluorescent Materials
Authors: José Jarib Alcaraz‐Espinoza | Guadalupe Ramos‐Sánchez | Jhon Harrison Sierra-Uribe | Ignacio González
Source: ACS Applied Energy Materials (article, 2021-08-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Supramolecular Assembly of Nanostructured Conducting Polymer Hydrogels by Hydrotropic Agents for Outstanding Supercapacitive Energy Storage Conducting polymer hydrogels (CPHs) are relevant to energy storage due to their micro-nanoscale three-dimensional network combined with a high electronic conductivity and electrochemical activity. The successful implementation of CPHs as an energy storage material requires solving two barriers: (1) low capacitance and electronic conductivity of current CPHs and (2) the lack of simple and scalable chemical synthesis routes. In this work, we propose a different approach for the synthesis of CPHs based on a supramolecular self-assembly induced by hydrotropic agents. The proposed synthesis method induces the formation of networks with superior electronic conductivity which does not require the addition of costly additives. Herein, para-toluene sulfonic acid (p-TSA) was proposed to produce CPHs of polypyrrole (PPy). The method was further extended to other polymer and hydrotropic agents as polyaniline and camphor sulfonic acid, demonstrating the versatility of the synthesis method. It was found that morphology and physical–chemical and electrochemical properties of PPy-CPHs can be fine-tuned with the amount of doping agents. The optimized PPy-CPHs sample possesses a high specific gravimetric capacitance of 560 F g–1 and an areal capacitance of 695 mF cm–2 at 0.75 A g–1 in addition to a capacitance retention of 72% at 10 A g–1, significantly higher than most state of the art PPy electrodes. Characterization suggests that CPH’s faster charge transfer and enhanced ionic and electronic conductivity are due to the higher degree of conjugation, porosity, and size of polymer clusters. Moreover, the symmetric supercapacitor devices with liquid and solid electrolytes exhibit an excellent energy storage performance with a maximum energy density of 13 W h kg–1 and power density of 3.6 kW kg–1. These devices also exhibit a capacitance retention of 82% after 5000 cycles at 5 A g–1. Materials science ; Supercapacitor ; Polypyrrole ; Capacitance ; Self-healing hydrogels ; Conductive polymer ; Sulfonic acid ; Nanotechnology ; Conductivity ; Chemical engineering ; Polymer ; Gravimetric analysis ; Electrochemistry ; Electrode ; Polymer chemistry ; Polymerization ; Composite material ; Chemistry ; Organic chemistry ; Physical chemistry Supercapacitor Materials and Fabrication ; Conducting polymers and applications ; Advanced Sensor and Energy Harvesting Materials