jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Reissig, Hans-Ulrich
Source: Refubium (Universitätsbibliothek der Freien Universität Berlin) (article, 2025-01-01)
Field: Chemistry — Organic Chemistry

Computational Study of Ignored Pericyclic Reactions: Rearrangements of 1,2-Bis(Diazo)Alkanes to 1,2,3,4-Tetrazines and Subsequent Fragmentations An electrocyclic ring closure of bis-1,3-dipoles can afford six-membered heterocycles. This 8π-electron process was systematically analyzed by DFT calculations with 1,2-bis(diazo)alkane derivatives as possible precursor compounds and 1,2,3,4-tetrazines as products. The C2-symmetry of the transition state of the parent system points to a conrotatory ring closing event. The subsequent (6–2–2) cycloreversions of these elusive nitrogen-rich heterocycles to alkynes or nitriles and dinitrogen were also computationally investigated. The results show that the reactions are strongly dependent on the substitution pattern, but all are kinetically easily feasible delivering products of differing stability. The calculations can therefore provide important information for experimental endeavors to generate or even isolate so far unknown 1,2,3,4-tetrazines. The feasibility of carbene or 1,2,3-triazolyl-substituted nitrene intermediates for the formation of alkynes is also discussed. The experimental evidence for the proposed processes is enclosed presenting literature known examples of the fragmentation reactions which can most convincingly be explained by the intermediacy of 1,2,3,4-tetrazine derivatives. Furthermore, the electrocyclic ring closure reactions of five other types of bis-1,3-dipoles are calculated, demonstrating that this so far ignored 8π-electrocyclization process can establish a new route to interestingly composed heterocyclic compounds. Conrotatory and disrotatory ; Pericyclic reaction ; Ring (chemistry) ; Nitrene ; Carbene ; Electrocyclic reaction ; Closure (psychology) Click Chemistry and Applications ; Cyclopropane Reaction Mechanisms ; Chemical Reactions and Mechanisms
Authors: Jeppe K. Christensen | Simon H. Albrechtsen | Christian Petersen | Constant A. Schouder | Iker Sánchez-Pérez | Pedro Javier Carchi-Villalta | Massimiliano Bartolomei | Fernando Pirani | Tomás González‐Lezana | Henrik Stapelfeldt
Source: ArXiv.org (preprint, 2025-10-14)
Field: Chemistry — Spectroscopy

Time-resolved solvation dynamics of Li$^+$, Na$^+$ and K$^+$ ions in liquid helium nanodroplets In 2023, ultrafast pump-probe spectrocopy was used to record the solvation dynamics of a single Na$^+$ ion in a liquid helium droplet, atom-by-atom and with femtosecond time resolution [Albrechtsen \textit{et al., Nature}, 2023, \textbf{623}, 319]. Subsequently, theoretical studies showed that other alkali ions solvate in a similar manner but no experimental results were reported so far. Here, we extend the previous measurement on Na$^+$ to Li$^+$ and K$^+$ ions. A pump pulse selectively ionizes an alkali atom, initially residing at the droplet surface, and the ensuing solvation dynamics of the formed alkali cation, Ak$^+$, is followed by ionizing a Xe atom, located in the droplet interior, and recording the yields of Ak$^+$He$_n$ ions expelled from the droplet as a function of the pump-probe pulse delay. We find that Li$^+$, Na$^+$ and K$^+$ ions solvate with a binding rate of 1.8 $\pm$ 0.1, 1.8 $\pm$ 0.1 and 1.7 $\pm$ 0.1 He per ps, respectively. Furthermore, by comparing the number distribution of the Ak$^+$He$_n$ ion yields to the evaporation energies of these ion--He complexes, obtained by Path Integral Monte Carlo calculations, we identify signatures of the first solvation shells of Li$^+$, Na$^+$ and K$^+$. Lastly, we determine the time-dependent dissipation of the solvation energy from the vicinity of the three alkali ion species and find that the rate is highest (lowest) for Li$^+$ (K$^+$) Solvation ; Ion ; Alkali metal ; Femtosecond ; Ionization ; Helium ; Molecular dynamics ; Solvation shell Advanced NMR Techniques and Applications ; Quantum, superfluid, helium dynamics ; Spectroscopy and Quantum Chemical Studies
Authors: J. Rezek | Jan Koloros | Jiří Houška | R. Čerstvý | Stanislav Haviar | Jemal Yimer Damte | David Kolenatý | Pavel Baroch
Source: ArXiv.org (preprint, 2025-06-18)
Field: Materials Science — Materials Chemistry

Ultra-low-resistivity nitrogen-doped p-type Cu2O thin films fabricated by reactive HiPIMS We have successfully fabricated the nitrogen-doped cuprous oxide thin films on the amorphous standard soda-lime glass by reactive high-power impulse magnetron sputtering. The energy of film-forming particles was controlled by the value of pulse-averaged target power density, which has a significant impact on the elemental composition, structure and optoelectrical properties of the films. We have shown that the high-energy regime is more suitable for preserving Cu2O structure and leads to continuous substitution of oxygen by nitrogen compared with the low-energy regime. Moreover, in the high-energy regime, it is possible, to some extent, to independently control the electrical resistivity and optical properties. The electrical resistivity decreases down to 5 x10-2 ohm.cm at the optical band gap 2.0-2.3 eV. Special attention is paid to the formation of nitrogen molecules and their ability to form shallow acceptor states. Experimental results supported by our DFT calculations indicate that N2 replacing Cu in the Cu2O lattice is one possible (but not the only possible) acceptor. We have also found that the formation of nitrogen molecules is preferred in a high-energy regime. Electrical resistivity and conductivity ; Thin film ; Band gap ; Amorphous solid ; Acceptor ; High-power impulse magnetron sputtering ; Oxide ; Oxygen Copper-based nanomaterials and applications ; ZnO doping and properties ; Semiconductor materials and devices
Authors: Awatef Hattab | Alhadji Malloum | Jeanet Conradie | Zoubeida Dhaouadi | Nino Russo
Source: ChemPhysChem (article, 2025-11-03)
Field: Chemistry — Physical and Theoretical Chemistry

[Be(NH <sub>3</sub> ) <sub>16</sub> ] <sup>[2]</sup> <sup>+</sup> Microsolvation: Structure, Energetics, and Temperature Effects Gas-phase structural, energetic, and thermal properties of the [Be(NH<sub>3</sub>)<sub>16</sub>]<sup>2</sup> cluster are investigated by using the MP2/6-311++G** level of theory. The relative stability of isomers is explained evidencing the long-range electrostatic interactions and the spatial arrangement of NH<sub>3</sub> ligands around Be<sup>2</sup> <sup>+</sup> cation. The computed isomers binding strength and energies values are compared with that with beryllium cation coordinated from n = 1-6 ligands. A fitting approach yields an asymptotic binding energy of -32.2 kcal mol<sup>-1</sup>. Clustering energies suggest a compact and strongly bound first solvation shell, with weaker, secondary interactions beyond four to five ligands. The cluster thermal behavior is probed through temperature-dependent solvation enthalpies (ΔH) and free energies (ΔG) in gas phase. Results show that ΔG slightly decreases with temperature, while ΔH increases, emphasizing the role of entropy in thermal stabilization. Finally, Quantum Theory of Atoms in Molecules analysis reveals the coexistence of Be<sup>2</sup> <sup>+</sup>N coordination bonds and a network of NH…N hydrogen bonds. These cooperative noncovalent interactions significantly enhance both structural and energetic stability. Solvation ; Binding energy ; Molecule ; Hydrogen bond ; Non-covalent interactions ; Cluster (spacecraft) ; Beryllium ; Coordination number ; Thermal stability ; Thermochemistry Crystallography and molecular interactions ; Inorganic Fluorides and Related Compounds ; Synthesis and characterization of novel inorganic/organometallic compounds
Authors: Michelle Morrow
Source: Bioconjugation Insights (article, 2025-04-25)
Field: Chemistry — Organic Chemistry

Next-generation conjugates: small peptides to transform targeted cancer therapy “Our mission is to extend the therapeutic index of toxic payloads that effectively target cancer.”Lauren Coyle, Launch Commissioning Editor, Bioconjugation Insights, speaks with Michelle Morrow, Chief Scientific Officer, Avacta, about a novel drug delivery platform that utilizes a small peptide with a capping group conjugated to a cytotoxic cancer drug. She discusses the advantages of the platform over traditional ADC therapies including the improved precision and safety of cancer treatment.Bioconjugation Insights is the only dedicated provider of specialized, high-quality, Open Access digital content tailored to the bioconjugation field. To read more of our Open Access content, please register here. Bioconjugation ; Cancer therapy ; Cancer ; Drug ; Peptide ; Cancer treatment ; Drug delivery ; Cancer drugs Click Chemistry and Applications ; RNA Interference and Gene Delivery ; Biochemical and Structural Characterization
Authors: Emre Çevik | Atheel Almofleh | Şeyda Tuğba Günday | Sarah Mousa Asiri | Ayhan Bozkurt | Arfa Iqbal | Ömer Işık
Source: ChemistrySelect (article, 2025-04-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Design of Gel Electrolyte Bearing Redox Additive for High‐Performance Functional Supercapacitors Abstract In advanced supercapacitor applications, redox‐based electrolyte systems, particularly the synergistic potential of benzoquinone, glycerol, and phosphoric acid, plays a crucial role. However, the poor electrochemical stability of these systems limits their practical use. Benzoquinone, known for its high redox activity, was incorporated into glycerol as a stable host‐gel matrix and combined with phosphoric acid to produce a high‐ion‐conductivity electrolyte. In this study high electrochemical stability and improved charge–discharge kinetics of redox‐mediated supercapacitors were systematically addressed. The findings highlight the potential of this unique electrolyte system to contribute to the development of high‐performance and environmentally friendly energy storage devices for diverse applications. In this regard, a comparative study was conducted on aqueous and nonaqueous glycerol (Gly)/phosphoric acid (P) systems, where benzoquinone (BQ) was introduced as a redox mediator in varying fractions. This research provides valuable insights into the design and optimization of electrolyte compositions for next‐generation supercapacitors with enhanced efficiency and sustainability. Furthermore, the devices assembled with Gly3P50BQ exhibited a high specific energy of 48 Wh kg⁻¹ at 150 W kg⁻¹ and demonstrated a superior capacitance retention rate of 95% after 10,000 charge–discharge cycles. Supercapacitor ; Electrolyte ; Redox ; Bearing (navigation) ; Materials science ; Chemical engineering ; Chemistry ; Computer science ; Electrode ; Capacitance ; Inorganic chemistry ; Engineering ; Artificial intelligence Supercapacitor Materials and Fabrication ; Advanced battery technologies research ; Advancements in Battery Materials
Authors: Ipsita A. Banerjee | Amrita Das | Mary A. Biggs | Chau Anh N. Phan | Liana R. Cutter | Albert Ren
Source: Biomimetics (article, 2025-01-28)
Field: Materials Science — Biomaterials

Design and Development of Natural-Product-Derived Nanoassemblies and Their Interactions with Alpha Synuclein Biomimetic nanoassemblies derived from natural products are considered promising nanomaterials due to their self-assembling ability and their favorable interactions with biological molecules leading to their numerous applications as therapeutic agents or as molecular probes. In this work, we have created peptide nanoconjugates of two natural products, β-Boswellic acid (BA) and β-glycyrrhetinic acid (GH). Both BA and GH are known for their medicinal value, including their role as strong antioxidants, anti-inflammatory, neuroprotective and as anti-tumor agents. To enhance the bioavailability of these molecules, they were functionalized with three short peptides (YYIVS, MPDAHL and GSGGL) to create six conjugates with amphiphilic structures capable of facile self-assembly. The peptides were also derived from natural sources and have been known to display antioxidant activity. Depending upon the conjugate, nanofibers, nanovesicles or a mixture of both were formed upon self-assembly. The binding interactions of the nanoconjugates with α-Synuclein, a protein implicated in Parkinson's disease (PD) was examined through in silico studies and FTIR, circular dichroism and imaging studies. Our results indicated that the nanoassemblies interacted with alpha-synuclein fibrils efficaciously. Furthermore, the nanoassemblies were found to demonstrate high viability in the presence of microglial cells, and were found to enhance the uptake and interactions of α-Synuclein with microglial cells. The nanoconjugates designed in this work may be potentially utilized as vectors for peptide-based drug delivery or for other therapeutic applications. Alpha-synuclein ; Natural product ; Alpha (finance) ; Chemistry ; Nanotechnology ; Materials science ; Medicine ; Stereochemistry ; Parkinson's disease biodegradable polymer synthesis and properties ; Nanoparticle-Based Drug Delivery
Authors: Satish S. Singh | John Ohodnicki | Abhijit Roy | Mitali Patil | Boeun Lee | Prashant N. Kumta
Source: Materials (article, 2025-09-28)
Field: Materials Science — Biomaterials

Feasibility Study of Strontium-Containing Calcium Phosphate Coatings on Micro-Arc Oxidized AZ31 Calcium phosphate coatings are known for their osteoconductive prowess. In this work, calcium phosphate coatings were studied on a model biodegradable magnesium alloy of AZ31, primarily to provide improved corrosion protection and, more importantly, to confer in vitro cytocompatibility to the AZ31 alloy. Correspondingly, an aqueous-based approach was developed to deposit Sr<sup>2+</sup>-substituted calcium phosphates on micro-arc oxidized AZ31. Micro-arc oxidation was used mainly as a pretreatment technique due to improved homogeneity and adhesion strength in comparison to the coatings formed by the traditionally used alkaline and acidic pretreatment. Calcium phosphate coatings with up to 11.5 mol. % Sr were formed on micro-arc oxidized AZ31 substrates. Despite observation of greater than the intended 10 mol. % Sr to the calcium phosphate coatings as measured within the measurement error, biphasic mixtures of dicalcium phosphate dihydrate and poorly crystalline hydroxyapatite were formed. Micro-arc oxidation treatment, nevertheless, provided a slight improvement in corrosion protection compared to uncoated AZ31. However, much-improved corrosion protection was provided by the calcium phosphate coatings prepared either with or without Sr<sup>2+</sup>. The calcium phosphate coatings prepared with Sr<sup>2+</sup> were also observed to support improved MC3T3-E1 murine pre-osteoblast cell proliferation compared to the calcium phosphate coated substrates prepared without Sr<sup>2+</sup>. Calcium ; Phosphate ; Corrosion ; Magnesium phosphate ; Magnesium ; Conversion coating Magnesium Alloys: Properties and Applications ; Corrosion Behavior and Inhibition ; Bone Tissue Engineering Materials
Authors: Eswar Kumar Nadendla | Gangadhar P Vadla | Manohar Radhakrishnan | Raghavendra Sashi Krishna Nagampalli
Source: Preprints.org (preprint, 2025-05-05)
Field: Chemistry — Organic Chemistry

Tyrosine Kinases: Structural Insights and Mechanistic Roles in Cancer Progression and Therapeutics Protein tyrosine kinases (PTKs) are key enzymes of cellular signaling, regulating key processes such as proliferation, differentiation, migration, metabolism, and apoptosis. TKs modulate protein functions in normal and disease states by phosphorylation of tyrosine residues on target proteins. On this critical role, dysregulation of TKs is directly linked with disease progression, particularly in cancer, therefore making TKs an attractive target for therapeutic intervention. The PTK family is broadly classified into receptor tyrosine kinases (RTKs) and non-receptor tyrosine kinases (NRTKs), having variation at both structural and functional levels. RTKs are membrane-bound kinases that initiate intracellular signaling when they react with extracellular ligands, whereas NRTKs within the cytoplasm or nucleus convey intracellular signaling upon receptor activation. This review aims at the organization, mechanistic activity, and therapeutic potential of PTKs, with a particular focus on epidermal growth factor receptor (EGFR) and Src kinase as representative of RTK and NRTK, respectively. Additionally, this review also focuses on addressing emerging strategies to enhance TKI efficacy and overcome acquired resistance in cancer therapy. Receptor tyrosine kinase ; Tyrosine kinase ; Cancer ; Kinase ; Cancer research ; Protein-Tyrosine Kinases ; Biology ; Computational biology ; Medicine ; Signal transduction ; Cell biology ; Genetics Synthesis and Characterization of Heterocyclic Compounds ; Nuclear Receptors and Signaling ; Enzyme function and inhibition
Authors: O.Yu. Fedorenko | G.V. Lisachuk | N.A. Kryvobok | K.V. Bilogubkina | E.V. Chefranov
Source: Voprosy Khimii i Khimicheskoi Tekhnologii (article, 2025-12-01)
Field: Materials Science — Ceramics and Composites

Energy-efficient synthesis of ultra-dispersed powders for obtaining radio-transparent ceramics and composites The synthesis of refractory compounds requires special conditions and methods to ensure the effective conduct of the phase formation reactions to obtain target compounds. The main disadvantage of solid-phase synthesis of compounds that are of most significant interest for obtaining new functional ceramic materials is the high energy consumption due to high phase formation temperatures, the duration of the process, and the presence of impurities in raw materials that impair the properties of the synthesis products. It is the purity and reproducibility of the synthesis products, the high dispersion of the crystalline phase, and the uniformity of the grain size distribution that ensure not only the high strength of ceramics and composite materials for radio-engineering purposes, but also the necessary level of their functional properties, in particular, electrophysical properties. This work analyzes possible solutions to the problem of energy consumption in the synthesis of refractory compounds. The results of research aimed at the synthesis of compounds of the BaO(SrO, ZnO)–Al2O3–SiO2 system, necessary for the manufacture of radio-transparent ceramic and composite materials using the technology of exothermic synthesis from mixtures containing barium and strontium nitrates, silica, and organic reducing agents, are discussed. The formulation and technological parameters for obtaining the target compounds and their combinations using the nitrate-citrate method have been developed. Ultra-dispersed powders of refractory compounds (celsian, slawsonite, and willemite), as well as their combinations (slawsonite+celsian, slawsonite+willemite, celsian+willemite, slawsonite+celsian+willemite), have been obtained under laboratory conditions. With the involvement of X-ray phase analysis and scanning electron microscopy, the structural and phase features of the reaction products have been studied, and the factors determining their purity and particle morphology of the obtained ceramic powders have been identified. Ceramic ; Exothermic reaction ; Composite number ; Raw material ; Phase (matter) ; Dispersion (optics) ; Refractory (planetary science) ; Impurity ; Grain size Advanced ceramic materials synthesis ; Microwave-Assisted Synthesis and Applications ; Electrophoretic Deposition in Materials Science
Authors: Francisco G. Blandón‐Cumbreras | Marc Villabona | Julia Osmólska | Elizaveta F. Petrusevich | David Guzmán | Robert Zaleśny | Joanna Olesiak‐Bańska | Jordi Hernando | Uwe Pischel
Source: ChemistryEurope (article, 2025-08-02)
Field: Materials Science — Materials Chemistry

Photoswitching of the Two‐Photon Absorption of Donor‐Acceptor Substituted Dithienylethenes In this work the structural and electronic integration of push–pull systems with photoactivatable dithienylethenes (DTEs) is demonstrated. The light‐induced 6π‐electrocyclization of two asymmetrically substituted DTEs is used to conjugate an electron‐donor ( N , N ‐dimethylaminonaphthyl) and an acceptor part (aldehyde or trifluoromethyl) in the ring‐closed form of the photoswitch. This has consequences for the two‐photon absorption (2PA) properties, showing substantial shifts toward the near‐infrared spectral region for the conjugated push–pull isomer (e.g., 140 GM at 600 nm for the ring‐open isomer vs. 220 GM at 840 nm for the ring‐closed isomer for the compound with an aldehyde acceptor in THF solvent; measured by Z‐scan technique). The possibility to address the dithienylethene core in an all‐optical (irradiation at 365 nm for ring‐closing and at &gt;550 nm for ring‐opening) and reversible manner with good fatigue resistance (≈85%–90% signal recovery after seven switching cycles) provides a straightforward means to control 2PA properties. The experimental observations are rationalized with theoretical calculations (RI‐CC2/cc‐pVDZ level of theory), providing compelling evidence for the charge‐transfer nature of the 2PA‐active S 0 → S 2 transition. Two-photon absorption ; Absorption (acoustics) ; Acceptor ; Two-photon excitation microscopy ; Photochemistry ; Photon ; Materials science ; Chemistry ; Optics ; Physics ; Laser ; Fluorescence ; Quantum mechanics Photochromic and Fluorescence Chemistry ; Photoreceptor and optogenetics research ; Porphyrin and Phthalocyanine Chemistry
Authors: Patrick De Souza Sagioratto | Rúbia Eliza de Oliveira Schultz Ascari | Dalcimar Casanova
Source: Revista Brasileira de Computação Aplicada (article, 2025-12-07)
Field: Chemistry — Organic Chemistry

Comparative analysis of the Support Vector Machine and Convolutional Neural Network algorithms applied in classifying Acer Palmatum plant subspecies Background: Plant identification is an essential task as it provides valuable information about plant characteristics and helps determine the population and distribution of species. This paper presents an artificial intelligence solution developed to automatically classify subspecies of the plant species Acer palmatum based on images. A database containing subspecies of Acer palmatum was created, and supervised learning algorithms such as Support Vector Machine (SVM) and Convolutional Neural Network (CNN) were used to classify them. The experiments included different scenarios, such as original images, feature extraction, and data augmentation techniques. Results: The results showed that the CNN with transfer learning and data augmentation performed best, standing out as the best model tested regardless of the dataset evaluated. Conclusions: These findings suggest that advanced Machine Learning techniques can be highly effective in classifying subspecies of Acer palmatum, providing a valuable biodiversity monitoring and mapping tool. Subspecies ; Convolutional neural network ; Support vector machine ; Artificial neural network ; Identification (biology) ; Pattern recognition (psychology) ; Population Wood and Agarwood Research ; Plant-Derived Bioactive Compounds ; Smart Agriculture and AI