jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Luís Felipe Ferreira Motta Barbosa | Philip B. Dubowik | Manuel Armin Reddemann | Reinhold Kneer
Source: Review of Scientific Instruments (article, 2023-10-01)
Field: Chemistry — Spectroscopy

Development of a cavity ring-down spectrometer toward multi-species composition This work presents the development of a cavity ring-down spectrometer (CRDS) designed for the detection of several molecules relevant for air pollution, including the second overtone of ro-vibration transitions from CO at 1.58 µm and NO at 1.79 µm. A unique feature of this CRDS is the use of custom mirrors with a reflectivity of about 99.99% from 1.52 to 1.80 µm, enabling efficient laser coupling into the cavity while ensuring a minimum detectable absorbance of 1.1 × 10-10 cm-1 within an integration time of about 1.2 s. In this work, the successful implementation of the current CRDS is demonstrated in two different wavelength regions. At 1.79 µm, the transitions R17.5 and R4.5 of the second overtone of NO are detected. At 1.58 µm, carbon dioxide and water vapor from untreated ambient air are measured, serving as an example to investigate the suitability of a post-processing procedure for the determination of the molar fraction in a multi-species composition. This post-processing procedure has the benefit of being calibration-free and SI-traceable. Additionally, CRDS measurements of gas mixtures containing CO and CO2 are also shown. In the future, the advantages of the developed cavity ring-down spectrometer will be exploited in order to perform fundamental studies on the transport processes of heterogeneous catalysis by locally resolving the gas phase near a working catalytic surface. The possibility to cover a broad wavelength region with this CRDS opens up the opportunity to investigate different catalytic reactions, including CO oxidation and NO reduction. Overtone ; Spectrometer ; Cavity ring-down spectroscopy ; Absorbance ; Materials science ; Calibration ; Wavelength ; Optics ; Optoelectronics ; Analytical Chemistry (journal) ; Laser ; Spectral line ; Chemistry ; Physics ; Environmental chemistry Spectroscopy and Laser Applications ; Atmospheric Ozone and Climate ; Atmospheric chemistry and aerosols
Authors: Angelo Maspero | Federico Vavassori | Luca Nardo | Guglielmo Vesco | Jenny G. Vitillo | Andrea Penoni
Source: Molecules (article, 2023-06-10)
Field: Materials Science — Materials Chemistry

Synthesis, Characterization, Fluorescence Properties, and DFT Modeling of Difluoroboron Biindolediketonates We report a simple and efficient strategy to enhance the fluorescence of biocompatible biindole diketonates (bdks) in the visible spectrum through difluoroboronation (BF<sub>2</sub>bdks complexes). Emission spectroscopy testifies an increase in the fluorescence quantum yields from a few percent to as much as >0.7. This massive increment is essentially independent of substitutions at the indole (-H, -Cl, and -OCH<sub>3</sub>) and corresponds to a significant stabilization of the excited state with respect to non-radiative decay mechanisms: the non-radiative decay rates are reduced by as much as an order of magnitude, from 10<sup>9</sup> s<sup>-1</sup> to 10<sup>8</sup> s<sup>-1</sup>, upon difluoroboronation. The stabilization of the excited state is large enough to enable sizeable <sup>1</sup>O<sub>2</sub> photosensitized production. Different time-dependent (TD) density functional theory (DFT) methods were assessed in their ability to model the electronic properties of the compounds, with TD-B3LYP-D3 providing the most accurate excitation energies. The calculations associate the first active optical transition in both the bdks and BF<sub>2</sub>bdks electronic spectra to the <i>S</i><sub>0</sub> → <i>S</i><sub>1</sub> transition, corresponding to a shift in the electronic density from the indoles to the oxygens or the O-BF<sub>2</sub>-O unit, respectively. Density functional theory ; Excited state ; Fluorescence ; Radiative transfer ; Photochemistry ; Chemistry ; Time-dependent density functional theory ; Spectroscopy ; Atomic electron transition ; Indole test ; Fluorescence spectroscopy ; Physical chemistry ; Computational chemistry ; Spectral line ; Atomic physics ; Physics ; Stereochemistry ; Optics Luminescence and Fluorescent Materials ; Radical Photochemical Reactions ; Fluorine in Organic Chemistry
Authors: Yipeng Zhang | He Lou | Mingfeng Wang
Source: Chemistry - A European Journal (article, 2023-11-29)
Field: Materials Science — Materials Chemistry

Kinetic and Thermodynamic Control of Supramolecular Aggregation of Near Infrared Pyrrolopyrrole Cyanine Fluorophores Confined in Colloidal Nanoparticles Control of the intermolecular aggregation of organic π-conjugated molecules as chromophores is crucial for tuning their physical properties such as light absorption/emission, and energy and charge transfer. Lots of advances have been achieved in control of intermolecular aggregation of organic chromophores in solid states where an indefinitely large number of molecules are involved. However, much less understanding has been gained at a mesoscale of aggregates formed by well-defined organization of a deterministic number of chromophores, which has been realized in natural photosynthetic systems but still remains rare in manmade materials. Here, we report both the kinetic and the thermodynamic control of the supramolecular aggregation of a near-infrared cyanine dye, PPcy, and its derivatives confined in colloidal nanoparticles stabilized by surfactants in aqueous media. Our results demonstrate that both the aggregation number, the aggregation state and the optical properties of the PPcy chromophores are controllable through optimization of the alkyl and polymer chains tethered from PPcy, the effective concentration of the chromophore inside each particle, and the surfactants utilized to stabilize the colloids in water. Cyanine ; Chromophore ; Intermolecular force ; Supramolecular chemistry ; J-aggregate ; Polymer ; Particle aggregation ; Molecule ; Nanoparticle ; Absorption (acoustics) ; Chemical physics ; Photochemistry ; Chemistry ; Materials science ; Fluorescence ; Nanotechnology ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Spectroscopy and Quantum Chemical Studies ; Photochemistry and Electron Transfer Studies
Authors: Zhen-Yu Wang | Daniel M. Többens | Alexandra Franz | Stanislav N. Savvin | Joachim Breternitz | Susan Schorr
Source: Journal of Materials Chemistry C (article, 2023-12-14)
Field: Materials Science — Materials Chemistry

Uncovering cation disorder in ternary Zn<sub>1+<i>x</i></sub>Ge<sub>1−<i>x</i></sub>(N<sub>1−<i>x</i></sub>O<sub><i>x</i></sub>)<sub>2</sub> and its effect on the optoelectronic properties Ternary nitrides have potential as sustainable solar absorber materials. Their structures permit unique bandgap tuning through cation disorder. We experimentally show two independent disorder modes influencing the bandgap in similar but distinct ways. Ternary operation ; Materials science ; Band gap ; Nitride ; Crystallography ; Condensed matter physics ; Nanotechnology ; Optoelectronics ; Physics ; Chemistry ZnO doping and properties ; Semiconductor materials and devices ; Ga2O3 and related materials
Authors: Efstratios Manousakis
Source: Physical review. B./Physical review. B (article, 2023-02-02)
Field: Materials Science — Materials Chemistry

Transition to an excitonic insulator from a two-dimensional conventional insulator In this paper, first, we present a general formulation to investigate the ground-state and elementary excitations of an excitonic insulator (EI) in real materials. In addition, we discuss the out-of-equilibrium state induced (albeit transiently) by high-intensity light illumination of a conventional two-dimensional (2D) insulator. We then present various band structure models which allow us to study the transition from a conventional insulator to an EI in 2D materials as a function of the dielectric constant, the conventional-insulator gap (and chemical potential), the bandwidths of the conduction and valence bands, and the Bravais lattice unit-cell size. One of the goals of this investigation is to determine which range of these experimentally determined parameters to consider in order to find the best candidate materials to realize the excitonic insulator. The numerical solution to the EI gap equation for various band structures shows a significant and interesting momentum dependence of the EI gap function $\mathrm{\ensuremath{\Delta}}(\stackrel{P\vec}{k})$ and of the zero-temperature electron and hole momentum distribution across the Brillouin zone. Last, we discuss the fact that these features can be detected by tunneling microscopy. Brillouin zone ; Insulator (electricity) ; Condensed matter physics ; Quantum tunnelling ; Band gap ; Dielectric ; Bravais lattice ; Electron ; Physics ; Materials science ; Chemistry ; Quantum mechanics ; Optoelectronics Electronic and Structural Properties of Oxides ; Quantum and electron transport phenomena ; Strong Light-Matter Interactions
Authors: Jingxiang Chen | Cheng Fu | Junye Li | Weiyu Tang | Xinglong Gao | Jingzhi Zhang
Source: Materials (article, 2023-05-16)
Field: Materials Science — Surfaces, Coatings and Films

Fabrication and Experimental Study of Micro/Sub-Micro Porous Copper Coating for Anti-Icing Application Micro and sub-micro-spherical copper powder slurries were elaborately prepared to fabricate different types of porous coating surfaces. These surfaces were further treated with low surface energy modification to obtain the superhydrophobic and slippery capacity. The surface wettability and chemical component were measured. The results showed that both the micro and sub-micro porous coating layer greatly increased the water-repellence capability of the substrate compared with the bare copper plate. Notably, the PFDTES-fluorinated coating surfaces yielded superhydrophobic ability against water under 0 °C with a contact angle of ~150° and a contact angle of hysteresis of ~7°. The contact angle results showed that the water repellency of the coating surface deteriorated with decreasing temperature from 10 °C to -20 °C, and the reason was probably recognized as the vapor condensation in the sub-cooled porous layer. The anti-icing test showed that the ice adhesion strengths of the micro and sub-micro-coated surfaces were 38.5 kPa and 30.2 kPa, producing a 62.8% and 72.7% decrease compared to the bare plate. The PFDTES-fluorinated and slippery liquid-infused porous coating surfaces both produced ultra-low ice adhesion strengths of 11.5-15.7 kPa compared with the other non-treated surfaces, which showed prominent properties for anti-icing and deicing requirement of the metallic surface. Materials science ; Contact angle ; Wetting ; Coating ; Composite material ; Porosity ; Copper ; Superhydrophobic coating ; Surface energy ; Layer (electronics) ; Adhesion ; Hysteresis ; Slurry ; Substrate (aquarium) ; Fabrication ; Metallurgy Surface Modification and Superhydrophobicity ; Icing and De-icing Technologies ; Adhesion, Friction, and Surface Interactions
Authors: Leśław B. Lahuta | Joanna Szablińska‐Piernik | Karolina Stałanowska | Marcin Horbowicz | Ryszard J. Górecki | Viorica Railean‐Plugaru | Paweł Pomastowski | Bogusław Buszewski
Source: Plants (article, 2023-04-12)
Field: Materials Science — Materials Chemistry

Exogenously Applied Cyclitols and Biosynthesized Silver Nanoparticles Affect the Soluble Carbohydrate Profiles of Wheat (Triticum aestivum L.) Seedling Cyclitols, such as <i>myo</i>-inositol and its isomers and methyl derivatives (i.e., d-<i>chiro</i>-inositol and d-pinitol (3-<i>O</i>-methyl-<i>chiro</i>-inositol)), are classified as osmolytes and osmoprotectants and are significantly involved in plant responses to abiotic stresses, such as drought, salinity and cold. Moreover, d-pinitol demonstrates a synergistic effect with glutathione (GSH), increasing its antioxidant properties. However, the role of cyclitols in plant protection against stresses caused by metal nanoparticles is not yet known. Therefore, the present study examined the effects of <i>myo</i>-inositol, d-<i>chiro</i>-inositol and d-pinitol on wheat germination, seedling growth and changes in the profile of soluble carbohydrates in response to biologically synthesized silver nanoparticles ((Bio)Ag NPs). It was found that cyclitols were absorbed by germinating grains and transported within the growing seedlings but this process was disrupted by (Bio)Ag NPs. Cyclitols applied alone induced sucrose and 1-kestose accumulation in seedlings slightly, while (Bio)Ag NP doubled the concentrations of both sugars. This coincided with a decrease in monosaccharides; i.e., fructose and glucose. Cyclitols and (Bio)Ag NPs present in the endosperm resulted in reductions in monosaccharides, maltose and maltotriose, with no effect on sucrose and 1-kestose. Similar changes occurred in seedlings developing from primed grains. Cyclitols that accumulated in grain and seedlings during grain priming with d-pinitol and glutathione did not prevent the phytotoxic effects of (Bio)Ag NPs. Monosaccharide ; Sucrose ; Fructose ; Inositol ; Seedling ; Germination ; Chemistry ; Glutathione ; Fructan ; Carbohydrate ; Food science ; Botany ; Biochemistry ; Biology ; Enzyme Nanoparticles: synthesis and applications ; Phytase and its Applications ; Selenium in Biological Systems
Authors: Agnieszka Szczygieł | Katarzyna Węgierek‐Ciura | Jagoda Mierzejewska | Anna Wróblewska | Joanna Rossowska | Natalia Anger | Bożena Szermer-Olearnik | Marta Świtalska | Tomasz M. Goszczyński | Elżbieta Pajtasz‐Piasecka
Source: PubMed (article, 2023-01-01)
Field: Materials Science — Biomaterials

The modulation of local and systemic anti-tumor immune response induced by methotrexate nanoconjugate in murine MC38 colon carcinoma and B16 F0 melanoma tumor models. Methotrexate (MTX) which is one of the longest-used cytostatics, belongs to the group of antimetabolites and is used for treatment in different types of cancer as well as during autoimmune diseases. MTX can act as a modulator enable to create the optimal environment to generate the specific anti-tumor immune response. A novel system for MTX delivery is its conjugation with high-molecular-weight carriers such as hydroxyethyl starch (HES), a modified amylopectin-based polymer applied in medicine as a colloidal plasma volume expander. Such modification prolongs the plasma half-life of the HES-MTX nanoconjugate and improves the distribution of the drug in the body. In the current study, we focused on evaluating the dose-dependent therapeutic efficacy of chemotherapy with HES-MTX nanoconjugate compared to the free form of MTX, and examining the time-dependent changes in the local and systemic anti-tumor immune response induced by this therapy. To confirm the higher effectiveness of HES-MTX in comparison to MTX, we analyzed its action using murine MC38 colon carcinoma and B16 F0 melanoma tumor models. It was noted that HES-MTX at a dose of 20 mg/kg b.w. was more effective in tumor growth inhibition than MTX in both tumor models. One of the main differences between the two analyzed tumor models concerned the kinetics of the appearance of the immunomodulation. In MC38 tumors, the beneficial change in the tumor microenvironment (TME) landscape, manifested by the depletion of pro-tumor immune cells, and increased influx of cells with strong anti-tumor activity was noted already 3 days after HES-MTX administration, while in B16 F0 model, these changes occurred 10 days after the start of therapy. Thus, the immunomodulatory potential of the HES-MTX nanoconjugate may be closely related to the specific immune cell composition of the TME, which combined with additional treatment such as immunotherapies, would enhance the therapeutic potential of the nanoconjugate. Methotrexate ; Melanoma ; Cancer research ; Immune system ; Tumor microenvironment ; Medicine ; Tumor progression ; Cancer ; Colorectal cancer ; Pharmacology ; Immunology ; Internal medicine Nanoparticle-Based Drug Delivery ; Nanoplatforms for cancer theranostics ; Immune cells in cancer
Authors: Andrea Alessio | Ettore Bernardi | Ekaterina Moreva | Ivo Pietro Degiovanni | Marco Genovese | Marco Truccato
Source: Sensors (article, 2023-12-29)
Field: Materials Science — Materials Chemistry

Limitations of Bulk Diamond Sensors for Single-Cell Thermometry The present paper reports on a Finite Element Method (FEM) analysis of the experimental situation corresponding to the measurement of the temperature variation in a single cell plated on bulk diamond by means of optical techniques. Starting from previous experimental results, we have determined-in a uniform power density approximation and under steady-state conditions-the total heat power that has to be dissipated by a single cell plated on a glassy substrate in order to induce the typical maximum temperature increase ΔTglass=1 K. While keeping all of the other parameters constant, the glassy substrate has been replaced by a diamond plate. The FEM analysis shows that, in this case, the maximum temperature increase is expected at the diamond/cell interface and is as small as ΔTdiam=4.6×10-4 K. We have also calculated the typical decay time in the transient scenario, which resulted in τ≈ 250 μs. By comparing these results with the state-of-the-art sensitivity values, we prove that the potential advantages of a longer coherence time, better spectral properties, and the use of special field alignments do not justify the use of diamond substrates in their bulk form. Diamond ; Finite element method ; Materials science ; Substrate (aquarium) ; Transient (computer programming) ; Coherence (philosophical gambling strategy) ; Power density ; Field (mathematics) ; Steady state (chemistry) ; Power (physics) ; Temperature measurement ; Mechanics ; Optoelectronics ; Composite material ; Thermodynamics ; Chemistry ; Computer science ; Physics ; Mathematics Diamond and Carbon-based Materials Research ; Advanced Fiber Laser Technologies ; High-pressure geophysics and materials
Authors: Sayan Shee | Sowmya Shree Ranganathappa | Mahesh S. Gadhave | Romin Gogoi | Akkattu T. Biju
Source: Angewandte Chemie (article, 2023-11-21)
Field: Chemistry — Organic Chemistry

Enantioselective Synthesis of C−O Axially Chiral Diaryl Ethers by NHC‐Catalyzed Atroposelective Desymmetrization** Abstract Axially chiral diaryl ethers, a distinguished class of atropisomers possessing unique dual C−O axis, hold immense potential for diverse research domains. In contrast to the catalytic enantioselective synthesis of conventional single axis bearing atropisomers, the atroposelective synthesis of axially chiral ethers containing flexible C−O axis remains a significant challenge. Herein, we demonstrate the first N‐heterocyclic carbene (NHC)‐catalyzed synthesis of axially chiral diaryl ethers via atroposelective esterification of dialdehyde‐containing diaryl ethers. Mechanistically, the reaction proceeds via NHC‐catalyzed desymmetrization strategy to afford the corresponding axially chiral diaryl ether atropisomers in good yields and high enantioselectivities under mild conditions. The derivatization of the synthesized product expands the utility of present strategy via access to a library of C−O axially chiral compounds. The temperature dependency and preliminary investigations on the racemization barrier of C−O bonds are also presented. Atropisomer ; Desymmetrization ; Enantioselective synthesis ; Chemistry ; Axial chirality ; Kinetic resolution ; Catalysis ; Racemization ; Carbene ; Combinatorial chemistry ; Diphenyl ether ; Organic chemistry Axial and Atropisomeric Chirality Synthesis ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Synthetic Organic Chemistry Methods
Authors: Hengli Zhao | José A.C. Silva | Adriano Henrique | Farid Nouar | Christian Serre | Guillaume Maurin | Aziz Ghoufi
Source: Physical Chemistry Chemical Physics (article, 2023-01-01)
Field: Chemistry — Inorganic Chemistry

Adsorption and dynamics of linear and mono-branched hexane isomers in MIL-140 metal–organic frameworks Recent breakthrough experiments revealed the iso-reticular Zr-MOFs, MIL-140B and MIL-140C, as promising sorbents for the separation of C6 isomers. Interestingly while the ultra-small pore MIL-140B exhibited hexane isomer sorption hierarchy according to the normal boiling point order (<i>n</i>-C6 > 3MP (3-methyl pentane)), an uncommon shift in the elution order was observed in the larger pore MIL-140C. It was only speculated that the flexibility of the MOFs might be the origin of this intriguing behavior. Herein, flexible force field hybrid osmotic Monte Carlo combined with molecular dynamics simulations were carried out to unravel the microscopic mechanism of the adsorption and dynamics of both C6 isomers in MIL140B and MIL140C. Thermodynamically preferred adsorption of <i>n</i>-C6 over 3MP was predicted for MIL-140B and to a slightly less extent for MIL-140C. Interestingly while the mobility of <i>n</i>-C6 was found to remain higher than that of 3MP in the whole range of loading for MIL-140B, 3MP becomes more mobile than <i>n</i>-C6 at saturation in MIL-140C. This suggests that this kinetics order is most probably the origin of the inversion of the elution order observed experimentally for MIL-140C. The translational and rotational dynamics of the two guests in MIL-140B and MIL-140C was further understood in-depth. Adsorption ; Chemistry ; Hexane ; Molecular dynamics ; Boiling point ; Metal-organic framework ; Pentane ; Elution ; Chemical physics ; Chemical engineering ; Physical chemistry ; Computational chemistry ; Chromatography ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Advanced NMR Techniques and Applications ; Crystallography and molecular interactions
Authors: Sara Gómez‐Gil | Marta Solas | Samuel Suárez‐Pantiga | Roberto Sanz
Source: The Journal of Organic Chemistry (article, 2023-12-12)
Field: Chemistry — Organic Chemistry

Brønsted Acid-Catalyzed Synthesis of 4-Functionalized Tetrahydrocarbazol-1-ones from 1,4-Dicarbonylindole Derivatives A <i>p</i>-toluenesulfonic acid-catalyzed cascade reaction is reported for the synthesis of 4-functionalized tetrahydrocarbazolones via the reaction of 4-(indol-2-yl)-4-oxobutanal derivatives with a variety of nucleophiles in acetonitrile or hexafluoroisopropanol. After the initial intramolecular Friedel-Crafts hydroxyalkylation, the 3-indolylmethanol intermediate is subsequently activated and reacted with the external nucleophile. The reaction conditions are crucial to avoid alternative reaction pathways, allowing direct substitution reaction with thiols, (hetero)arenes, alkenes, or sulfinates. The procedure features high overall yields to access a diverse family of compounds bearing the tetrahydrocarbazole core. Chemistry ; Intramolecular force ; Catalysis ; Nucleophile ; Brønsted–Lowry acid–base theory ; Acetonitrile ; Reaction conditions ; Divergent synthesis ; Combinatorial chemistry ; Friedel–Crafts reaction ; Organic chemistry ; Medicinal chemistry Sulfur-Based Synthesis Techniques ; Catalytic C–H Functionalization Methods ; Synthesis of Indole Derivatives