jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Hanna Bukovska | Fernando García-Pérez | Natalia Brea Núñez | Laura J. Bonales | Andrés Velasco | M. A. Clavero | Javier Martı́nez | Alberto J. Quejido | Isabel Rucandio | M. Belén Gómez-Mancebo
Source: C – Journal of Carbon Research (article, 2023-07-05)
Field: Materials Science — Materials Chemistry

Evaluation and Optimization of Tour Method for Synthesis of Graphite Oxide with High Specific Surface Area Many of the graphene-based structures exhibit an adsorption capacity due to their high specific surface area (SSA) and micropore volume. This capacity makes them competent materials for applications in energy and environmental sectors where efficiency is highly dependent on these properties for applications, such as water decontamination, solar cells or energy storage. The aim of this work is to study graphene-related materials (GRM) for applications where a high SSA is a requirement, considering the ideal SSA of graphene ≅ 2600 m2g−1. For the synthesis of most of the GRMs, some oxidation method such as the Tour method is used to oxidize graphite to graphite oxide (GrO) as an initial step. Our work studies the optimization of this initial step to evaluate the best conditions to obtain GrO with the maximum possible SSA. The different parameters influencing the process have been evaluated and optimized by applying an experimental design (ED). The resulting materials have been characterized by Brunauer–Emmett–Teller (BET), elemental analysis (EA), X-ray diffraction (XRD) and Raman and scanning electron microscopy (SEM). The evaluation of the results shows a maximum SSA of GrO of 67.04 m2g−1 for a temperature of 60 °C, a time of 12 h, a H2O2 volume of 50 mL and 4 g of KMnO4. Graphene ; Materials science ; Graphite ; Raman spectroscopy ; Oxide ; Chemical engineering ; Microporous material ; Specific surface area ; Response surface methodology ; Graphite oxide ; Adsorption ; Volume (thermodynamics) ; Scanning electron microscope ; Nanotechnology ; Composite material ; Chemistry ; Organic chemistry ; Chromatography ; Optics ; Thermodynamics Graphene research and applications ; Graphene and Nanomaterials Applications ; Advancements in Battery Materials
Authors: Alvja Mali | Margot Verbeelen | Paul B. White | Alexander H. J. Staal | N. Koen van Riessen | Cyril Cadiou | Françoise Chuburu | Olga Koshkina | Mangala Srinivas
Source: Nanoscale (article, 2023-01-01)
Field: Materials Science — Materials Chemistry

The internal structure of gadolinium and perfluorocarbon-loaded polymer nanoparticles affects <sup>19</sup>F MRI relaxation times <sup>19</sup>F magnetic resonance imaging (<sup>19</sup>F MRI) is an emerging technique for quantitative imaging in novel therapies, such as cellular therapies and theranostic nanocarriers. Nanocarriers loaded with liquid perfluorocarbon (PFC) typically have a (single) core-shell structure with PFC in the core due to the poor miscibility of PFC with organic and inorganic solvents. Paramagnetic relaxation enhancement acts only at a distance of a few angstroms. Thus, efficient modulation of the <sup>19</sup>F signal is possible only with fluorophilic PFC-soluble chelates. However, these chelates cannot interact with the surrounding environment and they might result in image artifacts. Conversely, chelates bound to the nanoparticle shell typically have a minimal effect on the <sup>19</sup>F signal and a strong impact on the aqueous environment. We show that the confinement of PFC in biodegradable polymeric nanoparticles (NPs) with a multicore structure enables the modulation of longitudinal (<i>T</i><sub>1</sub>) and transverse (<i>T</i><sub>2</sub>) <sup>19</sup>F relaxation, as well as proton (<sup>1</sup>H) signals, using non-fluorophilic paramagnetic chelates. We compared multicore NPs <i>versus</i> a conventional single core structure, where the PFC is encapsulated in the core(s) and the chelate in the surrounding polymeric matrix. This modulated relaxation also makes multicore NPs sensitive to various acidic pH environments, while preserving their stability. This effect was not observed with single core nanocapsules (NCs). Importantly, paramagnetic chelates affected both <i>T</i><sub>1</sub> and <i>T</i><sub>2</sub><sup>19</sup>F relaxation in multicore NPs, but not in single core NCs. Both relaxation times of the <sup>19</sup>F nucleus were enhanced with an increasing concentration of the paramagnetic chelate. Moreover, as the polymeric matrix remained water permeable, proton enhancement additionally was observed in MRI. Gadolinium ; Relaxation (psychology) ; Nanoparticle ; Polymer ; Materials science ; Nuclear magnetic resonance ; Chemistry ; Chemical engineering ; Nanotechnology ; Composite material ; Medicine ; Physics Lanthanide and Transition Metal Complexes ; Advanced NMR Techniques and Applications ; Advanced MRI Techniques and Applications
Authors: Rasmus Walther | Jovana Krmar | Adrian Leistner | Bojana Svrkota | Biljana Otašević | Anđelija Malenović | Ulrike Holzgrabe | Ana Protić
Source: Pharmaceuticals (article, 2023-03-23)
Field: Chemistry — Spectroscopy

Analytical Quality by Design: Achieving Robustness of an LC-CAD Method for the Analysis of Non-Volatile Fatty Acids An alternative to the time-consuming and error-prone pharmacopoeial gas chromatography method for the analysis of fatty acids (FAs) is urgently needed. The objective was therefore to propose a robust liquid chromatography method with charged aerosol detection for the analysis of polysorbate 80 (PS80) and magnesium stearate. FAs with different numbers of carbon atoms in the chain necessitated the use of a gradient method with a Hypersil Gold C<sub>18</sub> column and acetonitrile as organic modifier. The risk-based Analytical Quality by Design approach was applied to define the Method Operable Design Region (MODR). Formic acid concentration, initial and final percentages of acetonitrile, gradient elution time, column temperature, and mobile phase flow rate were identified as critical method parameters (CMPs). The initial and final percentages of acetonitrile were fixed while the remaining CMPs were fine-tuned using response surface methodology. Critical method attributes included the baseline separation of adjacent peaks (α-linolenic and myristic acid, and oleic and petroselinic acid) and the retention factor of the last compound eluted, stearic acid. The MODR was calculated by Monte Carlo simulations with a probability equal or greater than 90%. Finally, the column temperature was set at 33 °C, the flow rate was 0.575 mL/min, and acetonitrile linearly increased from 70 to 80% (<i>v</i>/<i>v</i>) within 14.2 min. Acetonitrile ; Chromatography ; Formic acid ; Chemistry ; Oleic acid ; Elution ; Stearic acid ; High-performance liquid chromatography ; Volumetric flow rate ; Organic chemistry Analytical Chemistry and Chromatography ; Advanced Chemical Sensor Technologies ; Analytical Methods in Pharmaceuticals
Authors: Atsushi Tamura | Mamoru Osawa | Nobuhiko Yui
Source: Molecules (article, 2023-03-09)
Field: Materials Science — Biomaterials

Supermolecule—Drug Conjugates Based on Acid-Degradable Polyrotaxanes for pH-Dependent Intracellular Release of Doxorubicin Doxorubicin (DOX)-conjugated acid-degradable polyrotaxanes (PRXs) were designed as supramolecular drug carriers capable of releasing drugs in acidic cellular environments. Acid-degradable PRXs composed of α-cyclodextrin (α-CD) as a cyclic molecule, poly(ethylene glycol) (PEG) as a polymer axis, and <i>N</i>-triphenylmethyl (<i>N</i>-Trt) groups as an acid-labile stopper molecules were synthesized and DOX was conjugated with the threaded α-CDs in the PRXs. Because the acid-induced cleavage of <i>N</i>-Trt groups in PRXs leads to PRX dissociation, the DOX-modified α-CDs were released under acidic conditions (pH 5.0). The cytotoxicity of DOX-conjugated PRXs in colon-26 cells revealed significant cell death for DOX-conjugated PRXs after 48 h of treatment. Confocal laser scanning microscopy (CLSM) analysis revealed that the fluorescence signals derived from DOX-conjugated PRXs were observed in cellular nuclei after 48 h, suggesting that the DOX-modified α-CDs were released and accumulated in cellular nuclei. These results confirmed that acid-degradable PRXs can be utilized as drug carriers capable of releasing drug-modified α-CDs in acidic lysosomes and eliciting cytotoxicity. Overall, acid-degradable PRXs represent a promising supramolecular framework for the delivery and intracellular release of drug-modified α-CDs, and PRX-drug conjugates are expected to contribute to the development of pH-responsive drug carriers for cancer therapy. Conjugate ; Supermolecule ; Chemistry ; Doxorubicin ; Intracellular ; Biophysics ; Drug ; Combinatorial chemistry ; Biochemistry ; Pharmacology ; Organic chemistry ; Biology Nanoparticle-Based Drug Delivery ; Supramolecular Chemistry and Complexes ; Dendrimers and Hyperbranched Polymers
Authors: Xiupeng Wang | Ayako Oyane | Tomoya Inose | Maki Nakamura
Source: Pharmaceutics (article, 2023-04-21)
Field: Materials Science — Biomaterials

In Situ Synthesis of a Tumor-Microenvironment-Responsive Chemotherapy Drug Current chemotherapy still suffers from unsatisfactory therapeutic efficacy, multi-drug resistance, and severe adverse effects, thus necessitating the development of techniques to confine chemotherapy drugs in the tumor microenvironment. Herein, we fabricated nanospheres of mesoporous silica (MS) doped with Cu (MS-Cu) and polyethylene glycol (PEG)-coated MS-Cu (PEG-MS-Cu) as exogenous copper supply systems to tumors. The synthesized MS-Cu nanospheres showed diameters of 30-150 nm with Cu/Si molar ratios of 0.041-0.069. Only disulfiram (DSF) and only MS-Cu nanospheres showed little cytotoxicity in vitro, whereas the combination of DSF and MS-Cu nanospheres showed significant cytotoxicity against MOC1 and MOC2 cells at concentrations of 0.2-1 μg/mL. Oral DSF administration in combination with MS-Cu nanospheres intratumoral or PEG-MS-Cu nanospheres intravenous administration showed significant antitumor efficacy against MOC2 cells in vivo. In contrast to traditional drug delivery systems, we herein propose a system for the in situ synthesis of chemotherapy drugs by converting nontoxic substances into antitumor chemotherapy drugs in a specific tumor microenvironment. In situ ; Tumor microenvironment ; Chemotherapy ; Drug ; Cancer research ; Drug development ; Medicine ; Chemistry ; Pharmacology ; Tumor cells ; Internal medicine Nanoparticle-Based Drug Delivery ; Nanoplatforms for cancer theranostics ; Cancer Research and Treatments
Authors: Yi Lü | Li Guo | Yeqiu Li | Yuan Yao
Source: Journal of Zhejiang University SCIENCE B (article, 2023-10-01)
Field: Materials Science — Biomaterials

Cellulose nanofibril matrix drives the dynamic formation of spheroids Multicellular spheroids, which mimic the natural organ counterparts, allow the prospect of drug screening and regenerative medicine. However, their application is hampered by low processing efficiency or limited scale. This study introduces an efficient method to drive rapid multicellular spheroid formation by a cellulose nanofibril matrix. This matrix enables the facilitated growth of spheroids (within 48 h) through multiple cell assembly into size-controllable aggregates with well-organized physiological microstructure. The efficiency, dimension, and conformation of the as-formed spheroids depend on the concentration of extracellular nanofibrils, the number of assembled cells, and the heterogeneity of cell types. The above strategy allows the robust formation mechanism of compacted tumoroids and hepatocyte spheroids. Spheroid ; Multicellular organism ; Extracellular matrix ; Matrix (chemical analysis) ; Biophysics ; Cellulose ; Nanotechnology ; Chemistry ; Cell ; Materials science ; In vitro ; Biology ; Biochemistry ; Chromatography Electrospun Nanofibers in Biomedical Applications ; Advanced Cellulose Research Studies ; 3D Printing in Biomedical Research
Authors: Filippo Campagnolo | Matteo Bevilacqua | Marco Baron | Cristina Tubaro | Andrea Biffis | Daniele Zuccaccia
Source: ChemPlusChem (article, 2023-10-30)
Field: Chemistry — Organic Chemistry

Insights on the Anion Effect in N‐heterocyclic Carbene Based Dinuclear Gold(I) Catalysts Dinuclear bisNHC (bis(N-heterocyclic carbene)) gold(I) complexes 3 a and 4 a of general formula [Au<sub>2</sub> Br<sub>2</sub> (bisNHC)] were tested as catalysts in the cycloisomerization of N-(prop-2-yn-1-yl)benzamide and in the hydromethoxylation of 3-hexyne in the presence of silver(I) activators bearing different counteranions. The catalytic performance of mononuclear NHC complexes (1 a, 2 a) in the same reactions was also studied. The results highlighted the fundamental role of both NHC ligand and counterion in the catalytic cycles and activation process: dinuclear catalysts exhibit higher initial activity even under milder conditions but suffer in terms of stability with respect to mono NHCs. Furthermore, a new dinuclear bisNHC gold(I) complex 4 b of general formula [Au<sub>2</sub> (OTs)<sub>2</sub> (bisNHC)] (OTs=p-toluenesulfonate) was successfully synthesized and characterized by means of NMR and ESI-MS analyses. Carbene ; Cycloisomerization ; Counterion ; Catalysis ; Chemistry ; Benzamide ; Ligand (biochemistry) ; Medicinal chemistry ; Ion ; Combinatorial chemistry ; Stereochemistry ; Polymer chemistry ; Organic chemistry ; Receptor Catalytic Alkyne Reactions ; Synthetic Organic Chemistry Methods ; Catalytic Cross-Coupling Reactions
Authors: Pol Gimeno‐Fonquernie | Jorge Albalad | Jason R. Price∥ | Witold M. Bloch | Jack D. Evans | Christian J. Doonan | Christopher J. Sumby
Source: Journal of Materials Chemistry C (article, 2023-12-22)
Field: Chemistry — Inorganic Chemistry

Topological analysis and control of post-synthetic metalation sites in Zr-based metal–organic frameworks MOFs formed from 8-connecting nodes and 4-connecting linkers can have the flu , scu and csq topologies. Here we show design criteria for making the rare sqc topology and how topology can be used to generate distinct post-synthetic metalation sites. Metalation ; Topology (electrical circuits) ; Network topology ; Materials science ; Metal-organic framework ; Nanotechnology ; Computer science ; Stereochemistry ; Organic chemistry ; Chemistry ; Mathematics ; Combinatorics Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Crystallography and molecular interactions
Authors: Hongjun Jin | Ziyan Wu | Weilin Lin | Yinye Chen | Jingran Zhang | Ruyi Zheng | Haibing Wei | Qinghua Chen | Qingrong Qian | Jianbin Huang | Jie Zhang | Yun Yan
Source: Small (article, 2023-04-08)
Field: Chemistry — Organic Chemistry

Formation of Size‐Controllable Tetragonal Nanoprisms by Crystallization‐Directed Ionic Self‐Assembly of Anionic Porphyrin and PEO‐Containing Triblock Cationic Copolymer The creation of anisotropic nanostructures with precise size control is desirable for new properties and functions, but it is challenging for ionic self-assembly (ISA) because of the non-directional electrostatic interactions. Herein, the formation of size-controllable tetragonal nanoprisms is reported via crystallization-directed ionic self-assembly (CDISA) through evaporating a micellar solution on solid substrates. First, ISA is designed with a crystalline polyethylene oxide (PEO) containing cationic polymer poly(2-(2-guanidinoethoxy)ethyl methacrylate)-b-poly(ethyleneoxide)-b-poly(2-(2-guanidinoethoxy)-ethylmethacrylate) (PG<sub>n</sub> -PEO<sub>230</sub> -PG<sub>n</sub> ) and an anionic 5,10,15,20-Tetrakis(4-sulfonatophenyl) porphyrin (TPPS) to form micelles in aqueous solution. The PG segments binds excessive TPPS with amplenet chargeto form hydrophilic corona, while the PEO segments are unprecedentedly dehydrated and tightly packed into cores. Upon naturally drying the micellar solution on a silicon wafer, PEO crystallizationdirects the micelles to aggregate into square nanoplates, which are further connected to nanoprisms. Length and width of the nanoprisms can be facilely tuned by varying the initial concentration. In this hierarchical process, the aqueous self-assembly is prerequisite and the water evaporation rate is crucial for the formation of nanostructures, which provides multiple factors for morphology regulating. Such precise size-control strategy is highly expected to provide a new vision for the design of advanced materials with size controllable anisotropic nanostructures. Materials science ; Micelle ; Ostwald ripening ; Ionic bonding ; Porphyrin ; Chemical engineering ; Cationic polymerization ; Aqueous solution ; Self-assembly ; Crystallization ; Copolymer ; Nanostructure ; Tetragonal crystal system ; Polymer ; Polymer chemistry ; Nanotechnology ; Organic chemistry ; Chemistry ; Phase (matter) Advanced Polymer Synthesis and Characterization ; Pickering emulsions and particle stabilization ; Surfactants and Colloidal Systems
Authors: Monika Kušter | Janez Kovač | Zoran Samardžija | Matej Komelj | Sorour Semsari Parapari | Matejka Podlogar | Jean‐Marie Dubois | Sašo Šturm
Source: Crystals (article, 2023-05-23)
Field: Materials Science — Materials Chemistry

Impact of Tuned Oxidation on the Surface Energy of Sintered Samples Produced from Atomised B-Doped Al-Cu-Fe Quasicrystalline Powders Super-hydrophobic surfaces and coatings have stimulated a great deal of research, with the aim being to achieve better wetting properties. Factors such as surface chemistry and roughness play an important role in changing the surface energy, which in turn leads to changes in the wettability. Here, we have analysed the time dependence of the oxide layer and possible surface adsorbates on the surface topography of an Al59Cu25Fe13B3 quasicrystalline material in relation to changes in the wettability. The quasicrystalline matrix phase was 94% of the sample volume, and it was covered by a very smooth, amorphous oxide layer. The AlB12 and AlFe2B2 boron-rich phases were embedded in the quasicrystalline material as a result of the 3 at.% boron addition, which made atomisation of the material a simpler process. Under ambient conditions, the sample was naturally covered by an oxide layer; therefore, it is referred to as “surfenergy” to distinguish it from the conventional surface energy of a bare quasicrystal surface. The growth of the oxide layer with atmospheric ageing and annealing at 500 °C in air for various times was investigated for both cases. The phase most prone to oxidation was the boron-rich AlFe2B2, which influenced the topography of the surface and accordingly the wetting behaviour of the specimen. We demonstrated that the surfenergy depends on the polar component, which is the most sensitive to the operating conditions. A correlation between the surfenergy components and the surface roughness was found. In addition, theoretical models to determine the wettability were included. Wetting ; Materials science ; Oxide ; Annealing (glass) ; Surface energy ; Surface roughness ; Quasicrystal ; Surface finish ; Contact angle ; Amorphous solid ; Boron ; Coating ; Chemical engineering ; Layer (electronics) ; Composite material ; Surface layer ; Analytical Chemistry (journal) ; Metallurgy ; Crystallography ; Chemistry ; Organic chemistry Quasicrystal Structures and Properties ; Mineralogy and Gemology Studies ; nanoparticles nucleation surface interactions
Authors: Аlexander А. Korlyukov | A.I. Stash | Alexander R. Romanenko | Damian Trzybiński | Krzysztof Woźniak | Анна В. Вологжанина
Source: Biomedicines (article, 2023-03-01)
Field: Chemistry — Physical and Theoretical Chemistry

Ligand-Receptor Interactions of Lamivudine: A View from Charge Density Study and QM/MM Calculations The nature and strength of interactions for an anti-HIV drug, <i>Lamivudine</i>, were studied in a pure crystal form of the drug and the ligand-receptor complexes. High-resolution single-crystal X-ray diffraction studies of the tetragonal polymorph allowed the drug's experimental charge density distribution in the solid state to be obtained. The QM/MM calculations were performed for a simplified model of the <i>Lamivudine</i> complex with deoxycytidine kinase (two complexes with different binding modes) to reconstruct the theoretical charge density distribution. The peculiarities of intramolecular interactions were compared with previously reported data for an isolated molecule. Intermolecular interactions were revealed within the quantum theory of 'Atoms in Molecules', and their contributions to the total crystal energy or ligand-receptor binding energy were evaluated. It was demonstrated that the crystal field effect weakened the intramolecular interactions. Overall, the energies of intermolecular interactions in ligand-receptor complexes (320.1-394.8 kJ/mol) were higher than the energies of interactions in the crystal (276.9 kJ/mol) due to the larger number of hydrophilic interactions. In contrast, the sum of the energies of hydrophobic interactions was found to be unchanged. It was demonstrated by means of the Voronoi tessellation that molecular volume remained constant for different molecular conformations (250(13) Å<sup>3</sup>) and increased up to 399 Å<sup>3</sup> and 521(30) Å<sup>3</sup> for the <i>Lamivudine</i> phosphate and triphosphate. Intramolecular force ; Intermolecular force ; Ligand (biochemistry) ; Crystallography ; Chemistry ; Density functional theory ; Tetragonal crystal system ; Charge density ; Molecule ; Crystal (programming language) ; Interaction energy ; Atoms in molecules ; Computational chemistry ; Crystal structure ; Stereochemistry ; Receptor ; Physics ; Organic chemistry Crystallography and molecular interactions ; HIV/AIDS drug development and treatment ; Crystallization and Solubility Studies
Authors: Andrea Gualandi | Francesco Calogero | Dario Corbisiero | Emanuele Pinosa | Pier Giorgio Cozzi
Source: Asian Journal of Organic Chemistry (article, 2023-12-21)
Field: Chemistry — Organic Chemistry

Reactivities of Photoredox Generated Nickel‐Nucleophilic Reactive Organometallic Species Abstract Dual photoredox catalysis has revolutionized the field of cross‐coupling reactions, enabling the discovery of numerous highly efficient reactions. This breakthrough is attributed to the exceptional combination of nickel catalysis with photoredox catalysis. Nickel exhibits both oxidative addition and reductive elimination processes, and a wide range of oxidation states (ranging from I to IV) accessible within a single catalytic cycle. Furthermore, nickel complexes are capable of catalyzing various processes through radical mechanisms. The latest feature has proven to be incredibly potent in facilitating the formation of new C−C and C−X bonds (X=H, O, S, N). The powerful combination of photoredox and nickel catalysis reveals an expansive domain of unexplored possibilities. It offers unparalleled opportunities for improving reactions and exploring innovative pathways. Under photoredox conditions, it is possible to form nucleophilic reactive organometallic intermediates, useful in reaction with electrophiles. We have devoted a research program towards the rediscovery and use of organometallic reagents, introduced by Corey, Hegedus, and Semmelack many years ago. The results unveiled the extraordinary capabilities of photoredox catalysis, enabling the creation and efficient utilization of potent nucleophilic organometallic reagents under mild conditions, free from the need for strong bases or stoichiometric metal reductants. Photoredox catalysis ; Chemistry ; Nucleophile ; Catalysis ; Electrophile ; Reagent ; Oxidative addition ; Combinatorial chemistry ; Nickel ; Organometallic chemistry ; Reactive intermediate ; Catalytic cycle ; Reductive elimination ; Photochemistry ; Organic chemistry ; Photocatalysis Radical Photochemical Reactions ; Sulfur-Based Synthesis Techniques ; Catalytic C–H Functionalization Methods