jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Klichchupong Dabsamut | Thanasee Thanasarnsurapong | Intuon Chatratin | Tosapol Maluangnont | Sirichok Jungthawan | Adisak Boonchun
Source: arXiv (Cornell University) (preprint, 2022-10-15)
Field: Materials Science — Materials Chemistry

Two-dimensional Penta-NiPS Sheets: Two Stable Polymorphs The discovery of new and stable two-dimensional (2D) materials with exotic properties is essential for technological advancement. Inspired by the recently reported penta-PdPSe, we proposed penta-NiPS as a new member of the penta-2D materials based on first-principles calculations. The penta-NiPS monolayer is stable in two polymorphs including the alpha phase with identical structure as penta-PdPSe, and the newly proposed beta phase with rotated sublayers. Comprehensive analysis indicated that both phases are thermodynamically, dynamically, mechanically, and thermally stable. The penta-NiPS is a soft material with 2D Young's modulus of Ea=208 Nm^-1 and Eb=187 Nm^-1 for the alpha phase and Ea=184 Nm^-1 and Eb=140 Nm^-1 for the beta phase. Interestingly, the alpha-penta-NiPS showed nearly zero Poisson's ratios along the in-plane direction, where its dimensions would be maintained when being extended. For electronic applications, we demonstrated that penta-NiPS is the wide band gap semiconductor with an indirect band gap of 2.35 eV for alpha phase, and 2.20 eV for beta phase. Monolayer ; Phase (matter) ; Semiconductor ; Materials science ; Band gap ; Crystallography ; Modulus ; Condensed matter physics ; Physics ; Nanotechnology ; Chemistry ; Optoelectronics ; Composite material ; Quantum mechanics 2D Materials and Applications ; MXene and MAX Phase Materials ; Chalcogenide Semiconductor Thin Films
Authors: Iffath Rizwana | Syeda Urooba Anam
Source: International Journal of Pharmaceutical Sciences Review and Research (article, 2022-11-15)
Field: Chemistry — Analytical Chemistry

Stability Indicating RP-HPLC Method for Development and Validation of Atogepant and its Application in Dissolution Studies A new, simple, precise, accurate and reproducible RP-HPLC method for Simultaneous estimation of Atogepant bulk and pharmaceutical formulations. Separation of Atogepant was successfully achieve Dona: WATERS 150X4.6mm, 5µm, C18 or equivalent in an isocratic mode utilizing K2HPO4: Methanol (55:45) at a flow rate of 1.0 mL/min and eluate was monitored at 272nm, with a retention time of 2.860 minutes for Atogepant respectively. The method was validated and their response was found to be linear in the drug concentration range of 50µg/ml to150 µg/ml for Atogepant. The values of the correlation coefficient were found to 1.000 for Atogepant respectively. The LOD and LOQ for Atogepant were found to be 0.050 and 0.165 respectively. This method was found to be good percentage recovery for Atogepant were found to be 100 respectively indicates that the proposed method is highly accurate. The specificity of the method shows good correlation between retention times of standard with the sample so, the method specifically determines the analyte in the sample without interference from excipients of tablet dosage forms. The method was extensively validated according to ICH guidelines for Linearity, Accuracy, Precision, Specificity and Robustness. Chromatography ; Analyte ; Correlation coefficient ; Linearity ; Retention time ; Accuracy and precision ; High-performance liquid chromatography ; Dissolution ; Methanol ; Elution ; Chemistry ; Linear correlation ; Analytical Chemistry (journal) ; Mathematics ; Statistics Analytical Methods in Pharmaceuticals ; Analytical Chemistry and Chromatography ; Antibiotics Pharmacokinetics and Efficacy
Authors: Jianyu Zhang | Parvej Alam | Siwei Zhang | Hanchen Shen | Lianrui Hu | Herman H. Y. Sung | Ian D. Williams | Jianwei Sun | Jacky W. Y. Lam | Haoke Zhang | Ben Zhong Tang
Source: ChemRxiv (preprint, 2022-01-06)
Field: Materials Science — Materials Chemistry

Secondary Through-Space Interactions: Achieving Single-Molecule White-Light Emission from Clusteroluminogens with Isolated Phenyl Rings Clusteroluminogens (CLgens) refer to some non-conjugated molecules that show visible light due to the formation of aggregates and unique electronic properties with through-space interactions (TSI). Although mature and systematic theories of molecular photophysics have been developed to study conventional conjugated chromophores, it is still challenging to endow CLgens with designed photophysical properties by manipulating TSI. Herein, three CLgens with non-conjugated donor-acceptor structures and different halide substituents with secondary TSI are designed and synthesized. These molecules show multiple emissions and even white-light emission in the crystalline state and the intensity ratio of these multiple emission peaks is easily manipulated by changing the halide atom and excitation wavelength. Experimental and theoretical results successfully disclose the electronic nature of these multiple emissions: through-space conjugation for short-wavelength fluorescence, through-space charge transfer based on secondary TSI for long-wavelength fluorescence, and room-temperature phosphorescence. The introduction of secondary TSI to CLgens not only enriches their varieties of photophysical properties but also inspires the establishment of novel aggregate photophysics for clusteroluminescence. Conjugated system ; Chromophore ; Phosphorescence ; Fluorescence ; Molecule ; Photochemistry ; Acceptor ; Wavelength ; Halide ; Materials science ; Chemistry ; Chemical physics ; Optoelectronics ; Optics ; Physics ; Polymer ; Organic chemistry Luminescence and Fluorescent Materials ; Porphyrin and Phthalocyanine Chemistry ; Nanoplatforms for cancer theranostics
Authors: Bruno Barbosa Rodrigues | Júlio Cesar Siqueira Rocha | Bismarck Vaz da Costa
Source: SSRN Electronic Journal (article, 2022-01-01)
Field: Materials Science — Polymers and Plastics

Phase Diagram of Flexible Polymers with Quenched Disordered Charged Monomers Phase diagram ; Polymer ; Monomer ; Materials science ; Diagram ; Chemical physics ; Statistical physics ; Polymer science ; Phase (matter) ; Chemical engineering ; Physics ; Composite material ; Engineering ; Mathematics ; Statistics ; Quantum mechanics Polymer crystallization and properties ; Material Properties and Applications ; Advanced Theoretical and Applied Studies in Material Sciences and Geometry
Authors: Kate K.S. Batista | Marta Lafuente | Sergio G. Rodrigo | Reyes Mallada | M.P. Pina
Source: 2022 IEEE Sensors (article, 2022-10-30)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Engineering Plasmonic Nanostructures for label-free SERS Detection of Neurotoxic Gases In this work, we explore the SERS based sensing capabilities of core-shell nanostructures for gas detection of neurotoxic agents at ppm level. These nanostructures generate intense localized surface plasmon resonances which are engineered by tuning geometrical parameters, in particular the aspect ratio of the metallic nanorods and the thickness of the silica mesoporous shell to extend the spectral window for the SERS based sensing from the visible to the near-infrared. This nanoarchitecture enables the integration of sampling preconcentration and detection of Sarin gas surrogate in a single SERS unit. Plasmon ; Nanorod ; Nanostructure ; Materials science ; Nanotechnology ; Mesoporous material ; Mesoporous silica ; Nanoparticle ; Optoelectronics ; Chemistry Gold and Silver Nanoparticles Synthesis and Applications ; Advanced biosensing and bioanalysis techniques ; Biosensors and Analytical Detection
Authors: Nicolas Madern | Judith Monnier | Jean‐Claude Crivello | Junxian Zhang | Karine Provost | V. Paul‐Boncour | Solenn Réguer | Dominique Thiaudière | M. Latroche
Source: Journal of Alloys and Compounds (article, 2022-12-31)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Investigations of the Mn–Ni–Sm ternary system by means of anomalous X-ray diffraction, X-ray absorption and DFT calculations Ternary operation ; Intermetallic ; Extended X-ray absorption fine structure ; XANES ; Crystallography ; Stacking ; Ternary numeral system ; Materials science ; Absorption (acoustics) ; Diffraction ; Powder diffraction ; Chemistry ; Phase (matter) ; Absorption spectroscopy ; Spectroscopy ; Physics ; Metallurgy Magnetic Properties of Alloys ; Rare-earth and actinide compounds ; Hydrogen Storage and Materials
Authors: Maria Cherevatskaya | Ilia Cherepanov | N. V. Kalganova | Andrej Frolov | Tatiana Bilova | Ludger A. Wessjohann | Sergey K. Moiseev
Source: ChemRxiv (preprint, 2022-12-13)
Field: Chemistry — Organic Chemistry

Sydnone imines as a new class of promising plant growth modulators and potential drought-protective phytoeffectors – a first experimental structure-activity-analysis overview Due to the oncoming climate changes, drought is the factor dramatically affecting crop yields and quality of produced foods. Therefore, to meet the growing food demand of the human population, improvement of drought tolerance of the currently cultured crops is required. The knowledge of the molecular mechanisms behind, e.g., drought tolerance provides a versatile instrument to correct the plant metabolism by chemical tools and to increase, thereby, their adaptive potential. This will preserve crop productivity and quality under water deficit conditions. Endogenously produced nitric oxide (NO) is one of the key signaling factors activating drought tolerance mechanisms in plants. Thus, application of synthetic NO donors as drought-protective phytoeffectors might support maintaining plant growth and productivity under dehydration conditions. Sydnone imines (Sydnonimines) are a class of clinically established mesoionic heterocyclic NO donors which represent a promising candidate group for such phytoeffectors. Therefore, here we provide an overview of the current progress in application of sydnone imines as exogenous NO donors in plants with a special emphasis on their potential as herbicides as well as herbicide antidotes, growth stimulants and suggest a deeper look into them as drought protectors, applicable to different plant species. We specifically address the structure-activity relationships in the context of the growth modulating activity of sydnone imines. According to the actual state of the art, growth-stimulating or antidote effects sre typical for 4-(α-hydroxybenzyl) derivatives of sydnone imines containing an alkyl substituent in position N-3. The nature of the substituent of the N-6 atom has a significant influence on the activity profile and the intensity of the effect. Nevertheless, further investigations are necessary to establish reliable structure-activity relationships (SAR). Consequently, sydnone imines might be considered as promising phytoeffector candidates, which are expected to exert either protective effects on plants growing under unfavorable conditions, or herbicidal ones, depending on the exact structure Sydnone ; Context (archaeology) ; Drought tolerance ; Population ; Biotechnology ; Agronomy ; Chemistry ; Biology ; Medicine ; Environmental health ; Organic chemistry Quinazolinone synthesis and applications ; Synthesis and Biological Evaluation ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
Authors: Yansong Ren | A. I. Kravchenko | Sheng Xie | Erik Svensson Grape | Zhen Yang | A. Ken Inge | Mingdi Yan | Olof Ramström
Source: ChemRxiv (preprint, 2022-04-20)
Field: Materials Science — Materials Chemistry

Stimuli-responsive Enaminitrile Molecular Switches as Tunable AIEgens Covering the Chromaticity Space and Acting as Vapor Sensors A family of responsive enaminitrile molecular switches showing tunable turn-on fluorescence upon switching and aggregation is reported. When activated by the addition of acid/base, isomerization around the C=C bond could be effectuated, resulting in complete and reversible switching to the E- or Z-isomers. Typical aggregation-induced emission (AIE) could be recorded for one specific state of the different switches. By subtle tailoring of the parent structure, a series of compounds with emission covering almost the full visible color range were obtained. The switchable AIE features of the enaminitrile structures enabled their demonstration as solid-state chemosensors to detect acidic and basic vapors, where the emission displayed an “off-on-off” effect. Single-crystal X-ray diffraction measurements and DFT calculations suggested a luminescence mechanism based on restriction of intramolecular rotation and an intramolecular charge transfer effect in the AIE luminogens. Intramolecular force ; Molecular switch ; Isomerization ; Aggregation-induced emission ; Chromaticity ; Luminescence ; Fluorescence ; Photochemistry ; Materials science ; Solid-state ; Chemistry ; Optoelectronics ; Molecule ; Stereochemistry ; Optics ; Physical chemistry ; Catalysis ; Organic chemistry Luminescence and Fluorescent Materials ; Molecular Sensors and Ion Detection ; Supramolecular Chemistry and Complexes
Authors: Eduardo Guzmán | Fernando Martínez‐Pedrero | Carles Calero | Armando Maestro | Francisco Ortega | Ramón G. Rubio
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2022-02-23)
Field: Materials Science — Materials Chemistry

A broad perspective to particle-laden fluid interfaces systems: from chemically homogeneous particles to active colloids Particles adsorbed to fluid interfaces are ubiquitous in industry, nature or life. The wide range of properties arising from the assembly of particles at fluid interface has stimulated an intense research activity on shed light to the most fundamental physico-chemical aspects of these systems. These include the mechanisms driving the equilibration of the interfacial layers, trapping energy, specific inter-particle interactions and the response of the particle-laden interface to mechanical perturbations and flows. The understanding of the physico-chemistry of particle-laden interfaces becomes essential for taking advantage of the particle capacity to stabilize interfaces for the preparation of different dispersed systems (emulsions, foams or colloidosomes) and the fabrication of new reconfigurable interface-dominated devices. This review presents a detailed overview of the physico-chemical aspects that determine the behavior of particles trapped at fluid interfaces. This has been combined with some examples of real and potential applications of these systems in technological and industrial fields. It is expected that this information can provide a general perspective of the topic that can be exploited for researchers and technologist non-specialized in the study of particle-laden interfaces, or for experienced researcher seeking new questions to solve. Homogeneous ; Colloidal particle ; Perspective (graphical) ; Colloid ; Particle (ecology) ; Chemical engineering ; Chemical physics ; Nanotechnology ; Materials science ; Chemistry ; Physics ; Computer science ; Statistical physics ; Engineering ; Geology Pickering emulsions and particle stabilization ; Micro and Nano Robotics
Authors: Crystal Smitherman
Source: Digital Archive @ GSU (article, 2022-04-12)
Field: Chemistry — Inorganic Chemistry

Biochemical and Mechanistic Studies of Nitronate Monooxygenase and Roles of Histidine Residues in Select Flavoprotein Oxidases Nitronate monooxygenase (NMO) catalyzes the flavin-dependent oxidation of propionate 3-nitronate (P3N) via the formation of an anionic flavosemiquinone. The oxidation of substrate includes the formation of a peroxy-nitro acid intermediate. P3N is activated to its radical form via a single electron transfer onto the FMN cofactor forming the anionic flavosemiquinone. Reoxidation of FMN cofactor from the anionic semiquinone has been proposed to go through two routes dependent upon which radical species oxygen reacts with first, radical P3N or the semiquinone. The recent crystallographic determination of NMO from Cyberlindnera saturnus and steady-state kinetics revealed an allosteric activation effect on the enzyme by PEG 3350 with respect to P3N. Choline oxidase (CHO) catalyzes the two-step oxidation of choline to glycine betaine via an enzyme-bound FAD cofactor. In the first redox reaction, choline is activated to it alkoxide form by means of an enzyme-derived catalytic base, H466. This histidine residue has been shown to not only act as a general base but an electrostatic catalyst stabilizing the negative charge accumulated on the reduced flavin species as shown by replacing the residue with alanine, aspartate, and glutamine using site-directed mutagenesis. CHO was also observed to catalyze excited state reactions as facilitated by H466. Evidence for the ESR comes from the observation of a pL-dependence on the fluorescence emission of CHO in H2O and D2O. Using fluorescence spectroscopy and pH effects, a hydroxy-C4a flavin intermediate was detected in the wild-type and S101A variant with and without oxygen indicating the adduct formation was with an active site hydroxide ion. The mechanism of formation has been elucidated. Flavoprotein ; Monooxygenase ; Nitronate ; Chemistry ; Biochemistry ; Flavin-containing monooxygenase ; Histidine ; Flavin group ; Biology ; Genetics ; Enzyme ; Organic chemistry ; Cytochrome P450 Metal-Catalyzed Oxygenation Mechanisms ; Photosynthetic Processes and Mechanisms ; Enzyme-mediated dye degradation
Authors: Oliver J. Knowles | Linus O. Johannissen | Giacomo E. M. Crisenza | Sam Hay | David Leys | David J. Procter
Source: Angewandte Chemie (article, 2022-10-17)
Field: Chemistry — Organic Chemistry

A Vitamin B<sub>2</sub>‐Photocatalysed Approach to Methionine Analogues Access to new non-canonical amino acid residues is crucial for medicinal chemistry and chemical biology. Analogues of the amino acid methionine have been far less explored-despite their use in biochemistry, pharmacology and peptide bioconjugation. This is largely due to limited synthetic access. Herein, we exploit a new disconnection to access non-natural methionines through the development of a photochemical method for the radical α-C-H functionalization of sulfides with alkenes, in water, using inexpensive and commercially-available riboflavin (vitamin B<sub>2</sub>) as a photocatalyst. Our photochemical conditions allow the two-step synthesis of novel methionine analogues-by radical addition to unsaturated amino acid derivatives-and the chemoselective modification of peptide side-chains to yield non-natural methionine residues within small peptides. The mechanism of the bio-inspired flavin photocatalysis has been probed by experimental, DFT and TDDFT studies. Chemistry ; Methionine ; Stereochemistry ; Biochemistry ; Amino acid Click Chemistry and Applications ; Sulfur-Based Synthesis Techniques ; Radical Photochemical Reactions
Authors: Theodore A. Gazis | Peter D. Matthews
Source: ChemRxiv (preprint, 2022-11-17)
Field: Materials Science — Materials Chemistry

Reeling them in: Ph2PSiMe3 in the sequential formation of InP magic-sized clusters Indium phosphide magic-sized clusters (MSCs) have been identified as a key step in the growth of InP quantum dots (QDs). However, the need for elevated temperatures to form QDs from MSCs has limited our understanding of this transformation. Herein, we utilize Ph2PSiMe3 to identify additional MSC intermediate species, which absorb from 365 nm to 490 nm. Excitingly, particle growth was carried out at 100 C without the use of acidic surfactants. We show that despite being discrete, stable, and isolable sizes of MSCs, they form a reaction continuum, thus providing further insight into the growth mechanism of InP. Indium phosphide ; Quantum dot ; Indium ; MAGIC (telescope) ; Nanotechnology ; Materials science ; Chemical physics ; Chemical engineering ; Crystallography ; Optoelectronics ; Chemistry ; Physics ; Gallium arsenide ; Quantum mechanics ; Engineering Quantum Dots Synthesis And Properties ; Semiconductor Quantum Structures and Devices ; Molecular Junctions and Nanostructures
Authors: Thomas J. Kuczmera | Andreas Boelke | Boris J. Nachtsheim
Source: ChemRxiv (preprint, 2022-02-22)
Field: Chemistry — Organic Chemistry

Stabilization of Ethynyl-Substituted Aryl-λ3-Iodanes by Tethered N-Heterocylces A systematic investigation of ethynyl N-heterocycle-substituted-λ3-iodanes (ENHIs) is presented. In a straightforward one-pot synthesis these novel reagents can be obtained in high yields bearing a variety of N-heterocycles. Their reactivity as electrophilic alkyne group transfer reagents was benchmarked in well-established as well as novel inter- and intramolecular group transfer reactions and compared to literature-known ethynyl benziodoxolones. Reagent ; Electrophile ; Intramolecular force ; Aryl ; Alkyne ; Chemistry ; Reactivity (psychology) ; Combinatorial chemistry ; Transfer (computing) ; Group (periodic table) ; Medicinal chemistry ; Organic chemistry ; Computer science ; Parallel computing ; Catalysis Oxidative Organic Chemistry Reactions ; Catalytic C–H Functionalization Methods ; Vanadium and Halogenation Chemistry
Authors: Marija Nišavić | Gustav J. Wørmer | Cecilie Mølgaard Nielsen | Sofie M. Jeppesen | Johan Palmfeldt | Thomas B. Poulsen
Source: ChemRxiv (preprint, 2022-10-03)
Field: Chemistry — Organic Chemistry

oxSTEF reagents are tunable and versatile electrophiles for selective disulfide-rebridging of native proteins Site-selective disulfide rebridging has emerged as a powerful strategy to modulate structural and functional properties of proteins. Here, we introduce a novel class of electrophilic reagents, designated oxSTEF, that demonstrate excellent efficiency in disulfide rebridging via double thiol-exchange. The oxSTEF reagents are prepared using an efficient synthetic sequence which may be diverted to obtain a range of structural derivatives. We demonstrate highly selective rebridging of cyclic peptides and native proteins, such as human growth hormone, and absence of cross-reactivity with other nucleophilic amino acid residues. The oxSTEF-conjugates undergo glutathione-mediated disintegration under tumor relevant glutathione concentrations, which highlights the potential for use in targeted drug delivery. Finally, the α-dicarbonyl motif of the oxSTEF reagents enables “second phase” oxime ligation which furthermore increases the thiol-stability of the conjugates significantly. Reagent ; Chemistry ; Electrophile ; Combinatorial chemistry ; Glutathione ; Thiol ; Nucleophile ; Cysteine ; Conjugate ; Bioconjugation ; Disulfide bond ; Oxime ; Biochemistry ; Organic chemistry ; Enzyme Click Chemistry and Applications ; Adenosine and Purinergic Signaling ; Peptidase Inhibition and Analysis