jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Mariana González Medina
Source: theses.fr (ABES) (preprint, 2022-12-01)
Field: Chemistry — Organic Chemistry

Functional molecular motions in drug design : application to nicotinic acetylcholine receptors The study of the conformational changes occurring in a protein structure is essential to understand its function and how a protein can be modulated. This research project was started with the aim of studying the gating cycle of the alpha-4 alpha-5 beta-2 nAChR, propose new ways of modulating this receptor and developing a method to find novel modulators. The interest on the alpha-4 alpha-5 beta-2 receptor comes from GWAS studies that have associated a Single Nucleotide Polymorphism (SNP D398N) on the alpha-5 subunit, to nicotine addiction and lung cancer. Without experimental structures of the alpha-4 alpha-5 beta-2 nAChR, I lacked the structural information to understand its gating mechanism, information essential to perform drug design in specific effector sites. Therefore, as the first step in the development of this project I performed the in-silico modeling of alpha-4 alpha-5 beta-2 in resting, activated and desensitized states. Once I obtained satisfactory models, I computed the conformational transition path between the modeled states and used this conformational path to do cavity analysis. The cavity analysis on the transition path pre-validated the models by confirming the presence of known orthosteric and allosteric sites and I identified novel plausible effector sites that can be exploited to modulate alpha-4 alpha-5 beta-2 nAChR. As an initial approach to propose modulators for these novel cavities, I collected and curated the structural data of protein ligand pairs and trained a deep learning method to produce ligand shapes complementary to a protein pocket. In addition, to tackle the issue of how to synthesize in-silico generated compounds, I integrated a series of synthetic feasibility scores that allowed me to set thresholds and filters to continue studying only in-silico generated compounds with a predicted synthetic route available. The trained generative model can be used to generate novel compounds complementary to the selected alpha-4 alpha-5 beta-2, pockets extracted from the cavity analysis, but it can also be used to generate ligands for other proteins in future research projects. Acetylcholine receptor ; Nicotinic agonist ; Drug ; Receptor ; Pharmacology ; Nicotinic acetylcholine receptor ; Acetylcholine ; Computational biology ; Neuroscience ; Computer science ; Chemistry ; Medicine ; Biology ; Biochemistry Synthesis and biological activity ; Various Chemistry Research Topics ; Inorganic and Organometallic Chemistry
Authors: Pengfei Zhang | Jialu Xu | Shengtai Hou | Qiang Niu | Zheng-Hong Luo
Source:  (preprint, 2022-08-28)
Field: Chemistry — Organic Chemistry

Cyclic Extrusion Synthesis of Mesoporous Carbon-Supported Metal Catalysts for Selective Hydrogenation The mesoporous carbon-supported metal catalysts are important materials in heterogeneous catalysis. From the standpoint of process intensification, the current synthesis methods still suffer from several issues, such as the excessive use of toxic solvents, the time-consuming self-assembly process, and the difficulty of continuous production. Herein, we report a solvent-free and continuous route to synthesize mesoporous carbon-supported metal catalysts. Interestingly, the use of cyclic extrusion could promote the mixing, coordination, and assembly of catalyst precursors (tannin-metal salts-additives) by shearing and squeeze force. The as-made mesoporous carbon-supported nickel showed high surface areas (up to 512m2g-1), narrow pore size distribution (~10 nm), and good performance in the selective hydrogenation of nitrobenzene to aniline (Conv.&gt;99%; Sel.&gt;99%). In addition, the fluid property of catalyst precursors and the geometry of the twin-screw extrusion channel were studied, and the essence of this cyclic extrusion process is also discussed. Catalysis ; Mesoporous material ; Materials science ; Aniline ; Nitrobenzene ; Extrusion ; Chemical engineering ; Metal ; Carbon fibers ; Organic chemistry ; Chemistry ; Composite material ; Metallurgy ; Composite number Nanomaterials for catalytic reactions ; Electrocatalysts for Energy Conversion ; Catalytic Processes in Materials Science
Authors: James J. Race | Alex Heyam | Matthew A. Wiebe | J. Diego Garcia-Hernandez | Charlotte E. Ellis | Shixing Lei | Ian Manners | Andrew S. Weller
Source: Angewandte Chemie (article, 2022-11-17)
Field: Chemistry — Organic Chemistry

Polyphosphinoborane Block Copolymer Synthesis Using Catalytic Reversible Chain‐Transfer Dehydropolymerization Abstract An amphiphilic block copolymer of polyphosphinoborane has been prepared by a mechanism‐led strategy of the sequential catalytic dehydropolymerization of precursor monomers, H 3 B ⋅ PRH 2 (R=Ph, n‐hexyl), using the simple pre‐catalyst [Rh(Ph 2 PCH 2 CH 2 PPh 2 ) 2 ]Cl. Speciation, mechanism and polymer chain growth studies support a step‐growth process where reversible chain transfer occurs, i.e. H 3 B ⋅ PRH 2 /oligomer/polymer can all coordinate with, and be activated by, the catalyst. Block copolymer [H 2 BPPhH] 110 ‐ b ‐[H 2 BP(n‐hexyl)H] 11 can be synthesized and self‐assembles in solution to form either rod‐like micelles or vesicles depending on solvent polarity. Copolymer ; Catalysis ; Chemistry ; Monomer ; Oligomer ; Chain transfer ; Solvent polarity ; Micelle ; Polymer ; Polymer chemistry ; Amphiphile ; Chain (unit) ; Solvent ; Vesicle ; Organic chemistry ; Aqueous solution ; Membrane ; Radical polymerization Advanced Polymer Synthesis and Characterization ; Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Paige J. Moncure | Zoe C. Simon | Jill E. Millstone | Jennifer E. Laaser
Source: ChemRxiv (preprint, 2022-01-18)
Field: Materials Science — Materials Chemistry

The relationship between gel mesh and particle size in determining nanoparticle diffusion in hydrogel nanocomposites The diffusion of poly(ethylene glycol) methyl ether thiol (PEGSH) functionalized gold nanoparticles (NPs) was measured in polyacrylamide gels of various crosslinking densities. The molecular weight of the PEGSH ligand and particle core size were both varied to yield particles with hydrodynamic diameters ranging from 7 to 21 nm. Gel mesh size was varied from approximately 36 to 60 nm by controlling the crosslinking density of the gel. Because high molecular weight ligands are expected to yield more compressible particles, we expected the diffusion constants of the NPs to depend on their hard:soft ratios (where the hard component of the particle consists of the particle core and the soft component of the particle consists of the ligand shell). However, our measurements revealed that NP diffusion coefficients resulted primarily from changes in the overall hydrodynamic diameter and not the ratio of particle core size to ligand size. Across all particles and gels, we found that the diffusion coefficient was well-predicted by the confinement ratio calculated from the diameter of the particle and an estimate of the gel mesh size obtained from the elastic blob model. These results suggest that the elastic blob model provides a reasonable estimate of the mesh size that particles “see” as they diffuse through the gel. This work brings new insights into the factors that dictate how NPs move through polymer gels and will inform development of hydrogel nanocomposites for applications such as drug delivery in heterogeneous, viscoelastic biological materials. Particle size ; Materials science ; Diffusion ; Particle (ecology) ; Nanoparticle ; Viscoelasticity ; Chemical engineering ; Yield (engineering) ; Nanotechnology ; Composite material ; Thermodynamics ; Physics Pickering emulsions and particle stabilization ; Blood properties and coagulation
Authors: Soheila Ghasemi | Marzieh Owrang | Farzad Javaheri
Source: Research Square (preprint, 2022-11-10)
Field: Chemistry — Organic Chemistry

Kinetic and Equilibrium Function and Switchable Catalytic Activity of Some Thermo-Responsive Hydrogel Metal Absorbents Based on Modified PNIPAM Abstract Synthesis and identification of some thermo-responsive hydrogel metal absorbents based on Schiff base modified PNIPAM is described. PNIPAM hydrogel is produced through conventional free-radical polymerization method. The hydrogel is amino modified with different amines and then treated with various aldehydes to make polymeric Schiff-bases supposing to utilize as an absorbent for Cu salt. Characterization of the as-prepared hydrogels was performed properly and confirmed the corresponding structures. Kinetic and equilibrium function of the absorbents and the effect of distinct variables like pH, adsorbent amount and contact time in the absorption process are investigated in detail. Kinetic and adsorption isotherm data agreed with pseudo-second order model and Langmuir isotherm, respectively. The maximum value of adsorption capacity of the prepared adsorbent was around 8550 mg g-1. In addition, the corresponding switchable catalytic activity using one of the thermo-responsive hydrogel metal absorbents in the reduction of 4-nitro phenol to 4-amino phenol in the role of model reaction is examined. Adsorption ; Schiff base ; Catalysis ; Phenol ; Self-healing hydrogels ; Chemical engineering ; Langmuir adsorption model ; Materials science ; Metal ; Polymerization ; Chemistry ; Polymer chemistry ; Polymer ; Organic chemistry ; Composite material Nanomaterials for catalytic reactions ; Inorganic and Organometallic Chemistry ; Adsorption and biosorption for pollutant removal
Authors: Veronika Krbečková | Zuzana Šimonová | Petr Langer | Pavlína Peikertová | Kateřina Mamulová Kutláková | Barbora Thomasová | Daniela Plachá
Source: Research Square (preprint, 2022-05-18)
Field: Materials Science — Materials Chemistry

Effective and Reproducible Biosynthesis of Nanogold-composite Catalyst for Paracetamol Oxidation Abstract Pharmaceutical products are some of the most serious emergent pollutants in the environment, especially nowadays of the covid-19 pandemic. In this study, nanogold-composite was prepared, and its catalytic activity for paracetamol degradation was investigated. Moreover, for the first time, recycled waste diatomite earth (WDE) from beer filtration was used for reproducible gold nanoparticle (Au NPs) preparation. The yeast cell debris in the WDE are responsible for Au NPs biosynthesis. The WDE served as both a reducing and stabilizing agent for crystalline spherical 30 nm Au NPs as well as acting as a direct support matrix. The conversion of paracetamol was 62% and 67% after 72 hours in the absence or presence of light irradiation, respectively, with 0.0126 h − 1 and 0.0148 h − 1 reaction rate constants. The presented study demonstrates successful use of a waste material from the food industry for the nanogold-composite preparation and its application as a promising catalyst in paracetamol removal. Composite number ; Catalysis ; Chemistry ; Biosynthesis ; Combinatorial chemistry ; Business ; Chemical engineering ; Biochemistry ; Materials science ; Composite material ; Engineering ; Enzyme Advanced Nanomaterials in Catalysis ; Electrochemical sensors and biosensors
Authors: Amirreza Malekzadeh Dirin | Ehsan Saljoughi | Shirin Kiani | Seyed Mahmoud Mousavi
Source: Research Square (preprint, 2022-07-05)
Field: Materials Science — Biomaterials

Zein protein obtained from maize as a novel biodegradable membrane material for oxygen/nitrogen separation: membrane fabrication and characterization Abstract In this study, biodegradable zein protein obtained from maize was used as a novel material to prepare a membrane for oxygen/nitrogen separation. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), tensile test, X-ray diffraction (XRD) spectroscopy, differential scanning calorimetry (DSC), biodegradability test, and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were conducted for characterizing the zein membrane, and membrane properties was compared with that of the polymeric membranes reported in the literature. The developed zein membrane showed a significantly high thermal stability. The mechanical properties of the zein membrane were higher or comparable to those of the previously reported dense membranes. In addition, biodegradation in compost was significantly higher than the other membranes reported in the literature. The developed zein membrane provided a significantly high oxygen/nitrogen selectivity at 2 bar, which was superior to most of the previously reported data on the neat biodegradable polymers with dense structure. The permeability of oxygen and nitrogen at 2 bar was 0.67 and 0.12 barrer, respectively, which brought about the selectivity of 5.45 for oxygen/nitrogen separation. Thermogravimetric analysis ; Membrane ; Differential scanning calorimetry ; Fourier transform infrared spectroscopy ; Chemical engineering ; Materials science ; Nitrogen ; Oxygen permeability ; Biodegradation ; Thermal stability ; Polymer ; Oxygen ; Chemistry ; Polymer chemistry ; Organic chemistry ; Composite material Electrospun Nanofibers in Biomedical Applications
Authors: Martinus Heru Palmiyanto | Eko Surojo | Dody Ariawan | Fitrian Imaduddin
Source: Research Square (preprint, 2022-08-10)
Field: Materials Science — Polymers and Plastics

Fiber Glass/Kenaf Reinforced Thermoset Composite with Microcrystalline Cellulose as Filler in a Different Fluid Immersion Abstract Microcrystalline cellulose (MCC) is one of the good and environmentally friendly natural rigid fillers used in polymer matrix composites to improve mechanical properties. However, the reliability of this MCC composite cannot be ensured in a humid environment or submerged in water with different pH. This study investigated the addition of MCC filler to the absorption of distilled water (pH 7), seawater (pH8), and acid solution (pH 3), flexural strength, and flexural modulus of kenaf/glass fiber reinforced polymer composites. Soaking the composite for 60 days in distilled water and seawater showed an increase in the concentration of water absorption. Water absorption by the kenaf fibers causes the fibers to swell and provides an expansion to the matrix resulting in crack propagation and the growth of new cracks in the matrix. The behavior of the composite in an acidic solution shows a mass loss, and the matrix erodes on the surface and inside the material. The flexural strength and flexural modulus of the composite decreased at all immersions. The addition of MCC as a reinforcing filler for thermoset composites increases the interfacial interaction between the matrix and the kenaf/glass fiber. The improved mechanical properties of MCC-filled composites in different pH environments create opportunities and reliability for use in different engineering applications. Composite material ; Kenaf ; Materials science ; Flexural strength ; Absorption of water ; Flexural modulus ; Composite number ; Distilled water ; Biocomposite ; Compounding ; Natural fiber ; Cellulose fiber ; Filler (materials) ; Microcrystalline cellulose ; Glass fiber ; Thermosetting polymer ; Polypropylene ; Fiber ; Cellulose ; Chemistry Natural Fiber Reinforced Composites ; Advanced Cellulose Research Studies ; Dielectric materials and actuators
Authors: Pra Cipta Buana Wahyu Mustika | Mega Mustikaningrum
Source: Jurnal Kimia Sains dan Aplikasi (article, 2022-11-16)
Field: Materials Science — Biomaterials

Fabrication of Cellulose Nanocrystal (CNCs) Based Biosorbent From Oil Palm Trunks Through Acid Hydrolysis With Sonication Assisted and Adsorption Kinetic Study Developing cellulose nanocrystal (CNCs) preparation techniques is a challenge confronted by many researchers. The advantages of property remain the reason for research to be developed. To deal with this issue, it is essential to conduct research related to process optimization, particularly in the hydrolysis process, which is the primary step in forming CNCs. In this study, the effect of sonication-assisted hydrolysis time was investigated. XRD characterization showed that the CNCs formed where the first group with specific peaks indicated. The crystallinity of CNCs decreased with increasing sonication duration, indicating that sonication-assisted hydrolysis was nonselective. The crystallinity of CNCs obtained for 15, 30, and 45 min was 61.6, 55.0, and 48.4 %, respectively. For sonication duration variations of 15, 30, and 45 min, the hydration diameter of CNCs was nearly identical at 42.35 ± 27.10, 42.99 ± 29.46, and 42.63 ± 29.49 nm, respectively. Similarly, the removal of methylene blue can be achieved using CNCs bio-adsorbent. The results of percent removal of methylene blue under sonication treatment of 15, 30, and 45 min of sonication were 73.34; 73.62; 72.86 %, respectively. The adsorption rate of CNCs follows the pseudo-second-order kinetic model, with the adsorption values under sonication treatment of 15, 30, and 45 min were 0.075 ± 0.008; 0.166 ± 0.013; 0.078 ± 0.005 g mg-1 min-1, respectively. Sonication ; Crystallinity ; Adsorption ; Hydrolysis ; Chemistry ; Nuclear chemistry ; Cellulose ; Chemical engineering ; Methylene blue ; Materials science ; Chromatography ; Organic chemistry ; Catalysis ; Photocatalysis Advanced Cellulose Research Studies ; Biofuel production and bioconversion ; Lignin and Wood Chemistry
Authors: Hengli Zhao
Source:  (preprint, 2022-02-18)
Field: Chemistry — Inorganic Chemistry

Computational exploration of the performances of mechanically constrained MOFs for hydrocarbon separation La séparation des hydrocarbures par adsorption utilisant les MOFs assistée par pression mécanique a été étudiée en utilisant la simulation moléculaire. Nous nous sommes concentrés sur MIL-140B et ZIF-8 où ont exploré plusieurs mécanismes microscopiques de séparation. Nous avons utilisé une technique de simulation intitulé Hybrid Osmotic Monte Carlo pour moduler la pression du gaz et la flexibilité de la structure induite par la pression mécanique externe en même temps. Avec l’application de la pression mécanique externe, nous avons pu augmenter de 80 % la sélectivité pour les isomères de l'hexane dans le MIL-140B et de 40 % pour le mélange binaire d’hexane linéaire / monobranché dans le ZIF-8. Nous avons également étudié la diffusion lente des hydrocarbures butane/butène dans ZIF-8, où la simulation dynamique moléculaire nous a aidés à avoir une vision de l’échelle atomistique. Nos résultats fournissent un nouveau concept de processus d'adsorption/séparation des MOF. Separation (statistics) ; Hydrocarbon ; Computer science ; Chemistry ; Machine learning ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Catalytic Processes in Materials Science ; Enhanced Oil Recovery Techniques
Authors: Ubah Promise Chima | Arezoo Fereidonian Dashti | Mardiana Saaid | Saifullahi Shehu Imam | Rohana Adnan
Source: Research Square (preprint, 2022-02-22)
Field: Materials Science — Materials Chemistry

Fabrication and Response Optimization of Moringa Oleifera-Functionalized Nanosorbents for the Removal of Diesel Range Organics from Contaminated Water Abstract The purpose of this research is to synthesize environmentally friendly nanosorbents capable of Diesel Range Organics (DRO) adsorption from contaminated water. Central Composite Design (CCD) analysis of response surface methodology (RSM) was employed in a model fitting of the variables predicting the adsorption efficiency of Moringa Oleifera -functionalized zerovalent iron particles (ZINPs) for the removal of DRO. The effects of the reaction parameters on the response were screened using 2 4 factorial design to determine the statistically significant independent variables. A quadratic model predicting the DRO adsorption efficiency of ZINPs with an F -value of 276.84 ( p -value &lt;0.0001) was developed. Diagnostic plots show that the predicted values were in excellent agreement with actual experimental values ( R 2 = 0.99). The maximum percentage removal of DRO of 92.6% was achieved after optimization, using the synthesized ZINPs after 8 hours of contact between DRO substrates and ZINPs at pH of 8, the temperature of 25 ºC, with an adsorbent dosage of 2 g/L and at composite desirability of 1. Characterization of ZINPs revealed the formation of quasi nanospheres and nanocubes with an average particle diameter of 50.9 ± 9.7, the crystallite size of 15.31 nm, a crystallinity index of 32.47%, and pore width of 75.69 – 88.59 nm. The adsorption equilibrium data modelling of ZINPs for adsorption of DRO was best described by Langmuir isotherm with the maximum monolayer coverage capacity of 7.194 mg/g. The separation factor T, indicated favourable adsorption. The adsorption kinetic data were consistent with pseudo-second-order kinetics indicating probable chemisorption. Moringa ; Contamination ; Contaminated water ; Diesel fuel ; Environmental science ; Waste management ; Environmental engineering ; Environmental chemistry ; Chemistry ; Engineering ; Ecology ; Biology ; Food science Nanoparticles: synthesis and applications ; Biodiesel Production and Applications
Authors: Thangunpai Kotchaporn | Hu Donghao | Su Xianlong | Kajiyama Mikio | Neves Marcos A. | Enomae Toshiharu
Source: Institutional Repositories DataBase (IRDB) (article, 2022-10-01)
Field: Materials Science — Materials Chemistry

Thermal Stability of Polycaprolactone Grafted Densely with Maleic Anhydride Analysed Using the Coats–Redfern Equation Thermal stability ; Maleic anhydride ; Polycaprolactone ; Stability (learning theory) ; Thermal ; Thermal analysis Enzyme Structure and Function ; X-ray Diffraction in Crystallography ; Crystallography and molecular interactions
Authors: Jun Zhao | Xin Dou | Qilong Tang | Peng Qiu | Junbo Li | Dongxia Gou | Tong Liu
Source: Research Square (preprint, 2022-06-02)
Field: Materials Science — Biomaterials

Preparation of chitosan/β-Cyclodextrin composite membrane and its adsorption mechanism for protein Abstract Food wastewater contains a large amount of protein, which will cause water pollution. In order to solve the problem of poor adsorption protein performance and easy disintegration by a pure chitosan membrane, the chitosan/modified β-cyclodextrin (CS/β-CDP) composite membranes were prepared for the adsorption of bovine serum albumin (BSA) in this work. The effect of preparation conditions (the mass ratio of CS and β-CDP, preparation temperature and glutaraldehyde addition) and adsorption conditions (temperature and pH) on BSA the prepared CS/β-CDP composite membrane was investigated in detail. The physical and chemical properties of pure CS membrane and CS/β-CDP composite membrane was investigated. The results showed that CS/β-CDP composite membrane has higher tensile strength, elongation at break, Young's modulus, contact angle properties, and lower swelling degree. The physicochemical and morphological attributes of composite membrane before and after adsorption of BSA were characterised by SEM, FT-IR and XRD. The results showed that the CS/β-CDP composite membrane adsorbed BSA by both physical and chemical mechanisms, and the adsorption isotherm, kinetics and thermodynamic experiments further confirmed its adsorption mechanism. As a result, the CS/β-CDP composite membrane of absorbing BSA was successfully fabricated, demonstrating the potential application prospect in environmental protection. Chitosan ; Cyclodextrin ; Adsorption ; Composite number ; Mechanism (biology) ; Chemistry ; Chemical engineering ; Membrane ; Polymer chemistry ; Materials science ; Chromatography ; Organic chemistry ; Composite material ; Engineering ; Biochemistry ; Physics Nanocomposite Films for Food Packaging ; Advanced Drug Delivery Systems ; Polymer Surface Interaction Studies