jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Hilal Daglar | Seda Keskın | Randall Q. Snurr
Source: Diffusion fundamentals. (article, 2025-11-03)
Field: Chemistry — Inorganic Chemistry

Investigating the Effects of Framework Flexibility on Water Adsorption in the Metal–Organic Framework NbOFFIVE-1-Ni via Molecular Modeling Many metal-organic frameworks (MOFs) exhibit complex structural flexibility, including breathing, swelling, and linker rotation.Understanding how these dynamic behaviors influence guest adsorption is crucial for designing MOFs for practical applications.In this study, 1 we employed a multiscale computational approach to gain molecular-level insight into the effect of flexibility on water adsorption in the MOF, NbOFFIVE-1-Ni.This material has narrow pores and good hydrothermal stability, which makes it attractive for CO2 capture.We utilized density functional theory (DFT) calculations and grand canonical Monte Carlo (GCMC) simulations to study the impact of NbOFFIVE-1-Ni structural flexibility on its water adsorption at different humidity conditions.To mimic possible changes in the MOF structure during water adsorption, we generated 14 derivatives of NbOFFIVE-1-Ni by performing DFT optimization of the structure at different water loadings and by rotating the pyrazine linkers in the framework.Studying the water adsorption in different configurations of NbOFFIVE-1-Ni demonstrated that DFT optimization in the presence of adsorbed water molecules and rotating the linkers are useful strategies to mimic its structural flexibility.Our results illustrate the significance of taking structural flexibility into account when designing MOFs for water adsorption and other relevant applications. Flexibility (engineering) ; Molecular model ; Adsorption ; Work (physics) ; Component (thermodynamics) Metal-Organic Frameworks: Synthesis and Applications ; Zeolite Catalysis and Synthesis ; Mesoporous Materials and Catalysis
Authors: Sebastian Kozuch
Source: Angewandte Chemie International Edition (article, 2025-10-29)
Field: Chemistry — Inorganic Chemistry

Resonant Dative Bonds The dative bond is an often underappreciated entity in the theory of chemical interactions, despite its explanatory and predictive potential. In this work, the concept is recovered to computationally design a novel resonant dative bonding pattern in ring molecules, which would be formally considered to be composed of multiple hypervalent and hypovalent atoms. Starting with the (HCPO)<sub>3</sub> ring arranged as alternating carbons and phosphorus, we propose that the major Lewis structure is composed of P═O double bonds and "semi-dative-semi-covalent" P─C bonds. The three carbons technically are a rare case of σ<sup>0</sup>π<sup>2</sup> carbenes; however, due to the stability granted by the delocalized, resonant dative bonds, we termed them "pseudo-carbenes". By experimenting with isoelectronic systems with other elements but with the same bonding pattern, we also observed pseudo-nitrenes, pseudo-silylenes, and dicoordinated halogens, among other unusual structures. Surprisingly, the isomeric rings with normal valence and traditional covalent bonds were found to be of much higher energy, suggesting that the resonant dative bonds can potentially be a source of highly stable molecular entities. Hypervalent molecule ; Dative case ; Covalent bond ; Valence bond theory ; Chemical bond ; Ring (chemistry) ; Single bond Synthesis and characterization of novel inorganic/organometallic compounds ; Chemical Reactions and Mechanisms ; Synthesis and Properties of Aromatic Compounds
Authors: Devyani G. Bhadane | Sachin B Somwanshi
Source: International Journal of Pharmaceutical Sciences and Drug Research (article, 2025-07-30)
Field: Chemistry — Analytical Chemistry

Optimized Formulation of Sitagliptin Fast Dissolving Tablets Using Statistical Design Techniques The study focused on developing and statistically optimizing sitagliptin-loaded fast-dissolving tablets (FDTs) utilizing a systematic DoE-based approach to enhance oral drug delivery and patient compliance in type 2-diabetes management. FDTs were prepared via direct compression with varying concentrations of variable excipients, Crospovidone (superdisintegrant) and Avicel 102 (binder) as part of a 3² full factorial design. The study assessed their impact on formulation attributes specifically hardness and disintegration time, alongside pre- and post-compression characteristics, dissolution performance, and stability over time. All developed formulations met pharmacopoeial standards. The optimized batch (B7) disintegrated in 34±3 seconds with adequate hardness of 4.5±0.09 kg/cm² and achieved 99.11% drug release within 30 minutes. Statistical analysis confirmed significant effects of both excipients, with crospovidone having a greater influence on disintegration. Stability studies over three months indicated no significant changes in key parameters. The results demonstrated a robust, cost-effective sitagliptin FDTs with improved dissolution properties, particularly beneficial for those with dysphagia or requiring immediate pharmacological response. Factorial experiment ; Sitagliptin ; Dissolution ; Statistical analysis ; Design of experiments ; Dosage form ; Dissolution testing Analytical Methods in Pharmaceuticals ; Drug Solubulity and Delivery Systems ; Pharmaceutical studies and practices
Authors: Benjamin J. Statham | Florian F. Mulks | Carsten Bolm
Source: Angewandte Chemie (article, 2025-06-10)
Field: Chemistry — Organic Chemistry

π‐Electron Donation at the Sulfoximidoyl Nitrogen Atom Abstract Knowledge of the physicochemical properties and the reactivity of functional groups is invaluable in organic chemistry. Although substantial understanding of properties/reactivities exists for standard functional groups, moieties which have entered the chemist's toolbox more recently are often not as well characterized. Sulfoximines constitute such a class of recently strongly promoted compounds, which nowadays have emerged as relevant molecules in an industrial context and in academic research. However, theoretical studies on the properties of the sulfoximidoyl group remain sparse. The aim of the present work was to investigate the interactions of the sulfoximidoyl nitrogen lone pairs with adjacent π‐acceptor orbitals. Density functional theory‐based (DFT‐based) methods were employed throughout the investigation to quantify the strength of these interactions and to characterize their influence on the properties/reactivities of N ‐functionalized sulfoximines. Although sulfoximines are commonly characterized as electron‐withdrawing, our analysis suggests a strong positive mesomeric effect of the sulfoximidoyl group at nitrogen. This effect increases the basicity and nucleophilicity of conjugated substituents at the sulfoximidoyl nitrogen atom. Nitrogen atom ; Nitrogen ; Atom (system on chip) ; Chemistry ; Organic chemistry ; Group (periodic table) ; Computer science Synthesis and Catalytic Reactions ; Organic Chemistry Cycloaddition Reactions ; Chemical Reactions and Mechanisms
Authors: Jan Martinek | Václav Hortvík | Miroslav Valtr | Petr Klapetek
Source: International Journal of Thermal Sciences (article, 2025-09-16)
Field: Materials Science — Materials Chemistry

Thermal diffusivity measurements using dual probe Scanning Thermal Microscopy We present a novel dual probe Scanning Thermal Microscopy setup and methodology for addressing measurements of thermal diffusivity using two microscale thermal probes placed at mutual distance between 1 to 60 μ m , monitoring propagation of heat pulses from one probe to another one through the studied sample. It is shown that even if the measured heat pulses are very weak in this configuration, they can be measured if the heat transfer via air is reduced by measuring in vacuum, radiative heat transfer is reduced by suitable measurement protocol and many pulses are averaged. Resulting signals show the expected dependencies and thermal diffusivity can be evaluated from them with a help of a numerical modeling. Diffusivity measurements are demonstrated on glasses and polymer samples and potential uncertainty sources are identified. Thermal diffusivity ; Microscale chemistry ; Heat transfer ; Thermal ; Laser flash analysis ; Scanning thermal microscopy ; Radiative transfer ; Microscopy Thermal properties of materials ; Thermography and Photoacoustic Techniques ; Thermal Radiation and Cooling Technologies
Authors: E. Katsipoulaki | K. Mourzidis | V. K. Jindal | David Lagarde | T. Taniguchi | K. Watanabe | Georgios Kopidakis | X. Marie | M. M. Glazov | E. Stratakis | Γ. Κιοσέογλου | Ioannis Paradisanos
Source: ArXiv.org (preprint, 2025-02-05)
Field: Materials Science — Materials Chemistry

Spin-valley polarization control in WSe$_2$ monolayers using photochemical doping We report on the influence of a photochemical doping method on the spin-valley polarization degree ($P_{c}$) of excitons in WSe$_2$ monolayers. By varying the carrier density and transitioning from an excess of electrons (n-type) to an excess of holes (p-type), we observe a non-monotonic dependence of $P_{c}$ on the doping level. Using controlled, single-shot photochlorination steps, we unveil this non-monotonic behavior, with $P_{c}$ reaching a minimum value of less than 10$\%$ at 78 K near the charge neutrality point, while increasing by a factor of three at a hole density of $5 \times 10^{11} \,\mathrm{cm^{-2}}$. The impact of the doping on $P_{c}$ is explained using a phenomenological model that accounts for various mechanisms influencing exciton polarization dynamics, including exciton-carrier scattering processes and exciton-to-trion conversion rates. Among these, exciton-carrier collisions emerge as the dominant mechanism driving the observed variations in $P_{c}$, while the exciton effective lifetime remains nearly independent of doping. These findings highlight the potential of photochemical methods for investigating valley physics and for effectively tuning the exciton polarization degree in transition metal dichalcogenide monolayers. Monolayer ; Doping ; Polarization (electrochemistry) ; Spin polarization ; Materials science ; Condensed matter physics ; Spin (aerodynamics) ; Photochemistry ; Chemical physics ; Optoelectronics ; Chemistry ; Physics ; Nanotechnology ; Physical chemistry ; Quantum mechanics ; Electron 2D Materials and Applications ; Heusler alloys: electronic and magnetic properties ; Chalcogenide Semiconductor Thin Films
Authors: Huayong Xie | Weijing Zhao | Hang Xiao | Yan Zhang | Yang Shen | Yuefang Gan | Qiong Tong | Yongxiang Zhao | Huan Tan | Jun Yang
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2025-10-29)
Field: Chemistry — Spectroscopy

<i>In Situ</i> Structure Determination of a Membrane Protein in Native Cellular Membranes by Proton-Detected Solid-State NMR Determining the structure of membrane proteins within their native cellular membranes remains a substantial challenge in structural biology. In this study, we present a proton-detected solid-state NMR (ssNMR) approach, combined with an optimized random partial protonation (RAP) labeling strategy, to determine the high-resolution structure of the large-conductance mechanosensitive channel (MscL) directly within native <i>E.coli</i> membranes (backbone RMSD = 1.9 Å). Our approach effectively suppresses background protein signals and achieves high spectral resolution and sensitivity at moderate MAS frequencies (40-60 kHz) by differentially tuning amide and side-chain protonation levels. Using advanced recoupling schemes, we obtained chemical shift assignments of side-chain protons by 3D hCCH spectra and <sup>1</sup>H-<sup>1</sup>H distance restraints from a series of 3D hNHH spectra. With 10% protonation in side-chains, the <sup>1</sup>H signals displayed linewidths of approximately 50Hz, facilitating the extraction of 49 long-range distance restraints between amide and side-chain protons, which are crucial for structural convergence. Ambiguities in the assignment of weak signals corresponding to distance restraints were resolved by integrating 3D hNHH experimental data with CS-Rosetta structural modeling. The resulting structure reveals a well-defined pentameric assembly, with transmembrane helix packing consistent with that observed in detergent environments. This study demonstrates significant sensitivity advantages of <sup>1</sup>H-detected over <sup>13</sup>C-detected <i>in situ</i> ssNMR methods, highlighting the potential of <sup>1</sup>H-detected ssNMR for the structure determination of a broad range of membrane proteins in native membranes. Protonation ; Membrane ; Amide ; Membrane protein ; Transmembrane protein ; Protein structure ; Mechanosensitive channels Advanced NMR Techniques and Applications ; Protein Structure and Dynamics ; Electron Spin Resonance Studies
Authors: Michael O. Okebiorun | Dalton Miller | Ken Cornell | Jim Browning
Source: Plasma (article, 2025-08-26)
Field: Materials Science — Biomaterials

Trypan Blue Image-Guided Removal of Surface-Based Bacterial Biofilms from Chicken Tissue Using Cold Atmospheric Pressure Plasma The study evaluates the efficacy of an image-guided CAP treatment method with a plasma device capable of rapid biofilm removal from chicken tissue. The plasma treatment operating configuration includes a gas mixture of Argon and H<sub>2</sub>O at a flowrate of 1.5 lpm. An X-Y stage was used to move the chicken sample below the stationary plasma scalpel at a speed of 0.1 mm/s. The discharge voltage and current were maintained between 3.2 and 3.7 kV (AC 20 kHz), and at 3 mA, respectively. The electrode gap and sample distance were set to 0.6 mm and 4 mm. This configuration facilitated effective biofilm removal, as confirmed by CFU analysis and 3D microscopic analysis showing a >99% reduction in biofilm post treatment with an etch rate of 2.2-5.8 μm/s and an impact width of up to 300 μm. The plasma scalpel electrode temperature reached 94.7 °C, while the targeted biofilm area was heated to 36.3 °C, suggesting non-thermal biofilm disruption. Three-dimensional microscopic analysis revealed biofilm thickness on chicken tissues ranging from 20 to 180 μm, comparable to biofilm loads on mammalian tissues. In conclusion, the study highlights the potential of CAP devices as a promising solution for biofilm debridement. Trypan blue ; Atmospheric-pressure plasma ; Biofilm ; Atmospheric pressure ; Chemistry ; Materials science ; Plasma ; Environmental science ; Bacteria ; Biology ; Geology ; Biochemistry ; Cell ; Physics Electrospun Nanofibers in Biomedical Applications ; Plasma Applications and Diagnostics
Authors: Qiao Zhiwu | Yitong ZHU | Jinxiang YANG | Yaoyun LAI | Chenchen Zhu | Bo Li | Haibo LIU | Yicong ZHU | Junteng lu | Yuchen Zhang
Source: Journal of Molecular Science (article, 2025-12-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Cyclization magic: theoretical design of externally controlled organic materials with intensified mid infrared absorption beyond 3000 nm This study presents the rational design of a series of oligo-<italic>α</italic>-BTD-TTF molecules, combining electron-accepting 2,1,3-benzothiadiazole (BTD) and redox-active tetrathiafulvalene (TTF) units, as novel materials with widely tunable optical absorption from the UV-Vis to the infrared (IR) region. Theoretical investigations reveal that the absorption range can be effectively tuned by varying the molecular charge state. This is achieved through redox reactions that planarize the TTF unit, thereby dramatically narrowing the HOMO-LUMO gap. A key finding is that molecules with an even number of positive charges, particularly the doubly charged species (e.g., <italic>cis</italic>-2<italic>α</italic>-BT<sup>2+</sup>), exhibit the narrowest gaps. <italic>cis</italic>-2<italic>α</italic>-BT<sup>2+</sup> demonstrates absorption covering the entire solar spectrum, making it a promising candidate for solar cell applications. Furthermore, cyclization of the oligomers, such as forming a six-membered BT ring, significantly enhances the absorption intensity in the mid-IR region due to increased molecular symmetry. This work demonstrates that redox state and cyclization are powerful, externally tunable strategies for manipulating the orbital energies and absorption properties of these materials, offering a new design pathway for advanced optical and electronic applications, including transparent photovoltaics and IR materials. Absorption (acoustics) ; Tetrathiafulvalene ; Photovoltaics ; Organic solar cell ; Solar cell ; Absorption spectroscopy ; Rational design ; Molecular orbital ; Redox Organic and Molecular Conductors Research ; Organic Electronics and Photovoltaics ; 2D Materials and Applications
Authors: Apostolos I. Sotiropoulos | Athanasios Masouras | Hristos T. Anastassiu | Vassilis Kostopoulos | Stavros Koulouridis
Source: Sensors (article, 2025-06-25)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Planar Electrically Large Structures of Carbon Nanotube Films with High Absorption and Shielding Performance in X-Band We consider light, high-absorbance, low-reflectance, electrically large layered sheet structures composed of thin carbon nanotube films. Such structures can be utilized in electromagnetic absorption and shielding applications in the X-band. They are of increasing interest in sensor-enabling technologies, stealth systems, and EMI shielding of electronic components. Especially in aerospace, this is crucial, as sensors are integral to aerospace engineering, enhancing the safety, efficiency, and performance of aircraft and spacecraft. To that end, sheets with carbon nanotube films embedded in a glass fiber polymer matrix are fabricated. The films have a thickness of around 70 μm. As shown, they cause a significant attenuation of the electromagnetic field. For shielding applications, a single-film sheet structure with total thickness of 1.65 mm presents an attenuation of around 25 dB in the transmission coefficient, while the attenuation can reach 37 dB for a two-film sheet structure with thickness of 1.8 mm. Shielding effectiveness performance is found to be greater than 35 dB for the two-film sheet structure. For applications requiring both high shielding and absorption, a two-layered structure with a thickness of 4.65 mm has been designed. The absorption, represented by the Loss Factor, is calculated to achieve values greater than 90%. The simulation results show good agreement with the measured data. The findings demonstrate a promising structure for materials suitable for sensor housings and smart electromagnetic environments where the suppression of electromagnetic interference is critical. In conclusion, the addition of carbon nanotube films, even at micrometer thicknesses, within a glass fiber polymer matrix significantly enhances both electromagnetic shielding and absorption performance. Electromagnetic shielding ; Materials science ; Attenuation ; Carbon nanotube ; Absorption (acoustics) ; Optoelectronics ; Attenuation coefficient ; Composite material ; Electromagnetic interference ; Optics ; Computer science ; Telecommunications Electromagnetic wave absorption materials ; Advanced Antenna and Metasurface Technologies ; Electromagnetic Compatibility and Measurements
Authors: Oleg I. Utesov | J. S. White | Priya R. Baral | Tapas Samanta | Chen Luo | F. Radu | L. Caron | Victor Ukleev
Source: Research Square (preprint, 2025-05-16)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Ill-defined magnons in the field-polarized phase of cubic helimagnet Magnon ; Condensed matter physics ; Phase (matter) ; Field (mathematics) ; Physics ; Materials science ; Mathematics ; Ferromagnetism ; Quantum mechanics Magnetic Properties of Alloys ; Geomagnetism and Paleomagnetism Studies ; Magnetic properties of thin films
Authors: Vibha | Sujata Sanghi | Ashish Agarwal | Ekta Arya | Shalu Kaushik | Meenal Chauhan
Source: Indian Journal of Pure & Applied Physics (article, 2025-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Structural, Dielectric and Magnetic Characterization of Double Perovskite BaLaCuSbO6 This work highlights a comprehensive investigation of the structural, dielectric and magnetic properties of the double perovskite BaLaCuSbO6. The material was synthesized via the solid-state reaction technique. X-Ray diffraction (XRD) and Rietveld refinement analysis confirmed that the material adopts a monoclinic structure with the I2/m space group at room temperature.The crystallite size, calculated using both the Debye-Scherrer equation and the Williamson-Hall plot, revealed nanoscale dimensions.Electron density mapping and SEM analysis confirmed structural integrity and uniform grain distribution. Dielectric studies performed over the frequency range of 10 Hz to 10 MHz exhibited strong dispersionat low frequencies, stabilizing at higher frequencies, consistent with Maxwell-Wagner polarization. Both impedance and conductivity analysis demonstrated that the material exhibits negative temperature coefficient of resistance (NTCR) characteristics, confirming its semiconducting nature at high temperatures. Modulus spectroscopy confirmed a non-Debye relaxation mechanism, and AC conductivity analysis suggested thermally activated charge transport. Magnetic characterization revealed the anti-ferromagnetic behavior of the material at room temperature,as observed from the nature of magnetic hysteresis loop. These findings suggest that BaLaCuSbO6 is a promising candidate for applications in electronic and magnetic devices. Rietveld refinement ; Dielectric ; Dielectric spectroscopy ; Crystallite ; Monoclinic crystal system ; Conductivity ; Perovskite (structure) ; Relaxation (psychology) ; Hysteresis Magnetic and transport properties of perovskites and related materials ; Advanced Condensed Matter Physics ; Microwave Dielectric Ceramics Synthesis
Authors: A. Ghotbi Varzaneh | P. Kameli | Marco Antonio Meraz Ríos | B. Aslibeiki | I. Orue | Tapati Sarkar | A. V. Chernenko | Manfred Kohl | Jingyuan Xu | Daniel Salazar
Source: Advanced Electronic Materials (article, 2025-11-19)
Field: Materials Science — Materials Chemistry

Tailoring Ni–Co–Mn–Sn Ribbons by Ge Doping for Enhanced Magnetocaloric Effect Abstract Micro‐grained high surface‐to‐volume ratio thin ribbons of magnetic shape memory Ni 42 Co 8 Mn 39 Sn 11‐ x Ge x ( x = 1, 2, 3) alloys are prepared, and their martensitic transformation (MT) behavior, magnetic and magnetocaloric properties are investigated. X‐ray diffraction reveals that the incorporation of Ge consistently decreases the lattice parameters and the transformation volume change, thereby improving geometric compatibility between martensitic and austenitic crystal lattices. This improvement facilitated a reduction of the thermal hysteresis of MT to a minimum of ≈12.1 K at the Ge concentration of x = 2. Direct measurements of adiabatic temperature changes show that the x = 2 alloy (SnGe2 ribbon) exhibited the highest peak value (≈2 K) at a moderate magnetic field change of 1.96 T. In addition, SnGe2 ribbon demonstrates exceptional isothermal entropy changes of ΔS iso = 35.5 J kg −1 K −1 K at 7 T and 22.8 J kg −1 K −1 K at 2 T, which are competitive with those of bulk alloys and surpassing previously reported melt‐spun ribbons of the Heusler‐type magnetocaloric materials. The significance of intricate microstructure in boosting the magnetocaloric effect is emphasized. These results highlight the substantial potential of Ni–Co–Mn–Sn–Ge thin ribbons as highly effective, micro‐sized magnetocaloric materials for cutting‐edge solid‐state refrigeration systems. Magnetic refrigeration ; Diffusionless transformation ; Isothermal process ; Austenite ; Shape-memory alloy ; Alloy ; Microstructure ; Ribbon ; Martensite Shape Memory Alloy Transformations ; Magnetic and transport properties of perovskites and related materials ; Ferroelectric and Piezoelectric Materials