jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Jiayi Cen | Ioanna Pallikara | Jonathan M. Skelton
Source:  (preprint, 2021-08-12)
Field: Materials Science — Materials Chemistry

Structural Dynamics and Thermal Transport in Bismuth Chalcogenide Alloys We present a detailed study of the structural dynamics, energetic and dynamical stability and thermal transport of the bismuth chalcogenides Bi2S3, Bi2Se3 and Bi2Te3 and their alloys. The differing activities of the Bi cation lone pairs in Bi2S3, Bi2Se3 and Bi2Te3 lead to competition between orthorhombic Pnma and rhombohedral R-3m phases, with the latter favored by heavier chalcogen atoms, while the reported non-ambient phases of Bi2Se3 and Bi2Te3 show phonon instabilities under ambient conditions. The Pnma structure has weaker chemical bonding and stronger phonon anharmonicity than the R-3m phase, resulting in an intrinsically lower lattice thermal conductivity. A thermodynamic model of Bi2[Se(1-x)S(x)]3 indicates that the R-3m structure is energetically favored only for low S content, but the stability window can potentially be extended at lower formation temperatures. Bi2[Se(1-x)Te(x)]3 in the R-3m phase shows substantial deviation from ideal solid-solution behavior, due to a strong energetic preference for the Se and Te atoms to occupy the interior and exterior sites, respectively, in the constituent quintuple layers. Strain-field fluctuations induced by inhomogeneities in the chemical bonding are shown to play a significant role in determining the heat transport in the alloy systems, and chalcogen disorder away from the preferred symmetric structure is found to be an important factor in the reduced thermal conductivity of Bi2SeTe2 compared to the Bi2Te3 endpoint. The microscopic insight from these modelling studies provides new insight into the bismuth chalcogenides and their alloys, which may inform ongoing research to optimize the thermoelectric performance of these and related materials. Chalcogen ; Bismuth ; Orthorhombic crystal system ; Anharmonicity ; Phonon ; Thermal conductivity ; Chalcogenide ; Materials science ; Lone pair ; Chemical physics ; Crystallography ; Condensed matter physics ; Crystal structure ; Chemistry ; Physics ; Metallurgy ; Molecule Advanced Thermoelectric Materials and Devices ; Thermal properties of materials ; Advanced Thermodynamics and Statistical Mechanics
Authors: Dawid Marcinkowski | Ariel Adamski | Maciej Kubicki | Giuseppe Consiglio | Violetta Patroniak | Tomasz Ślusarski | Muhammed Açıkgöz | Daria Szeliga | Nahir Vadra | Mirosław Karbowiak | Ireneusz Stefaniuk | Czesław Rudowicz | Adam Gorczyński | Maria Korabik
Source:  (preprint, 2021-08-25)
Field: Materials Science — Electronic, Optical and Magnetic Materials

NEW MODULAR ORGANIC PLATFORM FOR UNDERSTANDING THE EFFECT OF STRUCTURAL CHANGES ON SLOW MAGNETIC RELAXATION IN MONONUCLEAR OCTAHEDRAL COPPER(II) COMPLEXES Current advances in molecular magnetism are aimed at the construction of molecular nanomagnets and spin qubits for their utilization as high-density data storage materials and quantum computers. Mononuclear coordination compounds with low spin values of S=½ are excellent candidates for this endeavour, but their construction via rational design is limited. This particularly applies to the single copper(II) spin center, having been only recently demonstrated to exhibit slow relaxation of magnetisation in the appropriate octahedral environment. We have thus prepared a novel, modular organic scaffold that would allow one to gain general insight into how purposeful structural differences affect the slow magnetic relaxation in monometallic, transition metal complexes. As a proof-of-principle, we demonstrate how one can construct two, structurally very similar complexes with isolated Cu(II) ions in an octahedral ligand environment, the magnetic properties of which differ significantly. The differences in structural symmetry effects and in magnetic relaxation are corroborated with a series of experimental and theoretical techniques, showing how symmetry distortions affect the relaxation behaviour in these isolated Cu(II) systems. Our highly modular organic platform can be efficiently utilized for the construction of various transition-metal ion systems in the future, effectively providing a model system for investigation of magnetic relaxation via targeted structural distortions. Magnetism ; Relaxation (psychology) ; Octahedron ; Magnetization ; Chemical physics ; Ligand (biochemistry) ; Chemistry ; Nanomagnet ; Ion ; Copper ; Transition metal ; Materials science ; Crystallography ; Condensed matter physics ; Nanotechnology ; Physics ; Magnetic field ; Quantum mechanics ; Organic chemistry Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies
Authors: Robert Franz
Source: Data Archiving and Networked Services (DANS) (article, 2021-05-17)
Field: Materials Science — Materials Chemistry

Deactivation pathways in methane upgrading catalysis The abundance of methane has led to a strong interest to use methane as a feedstock in the chemical industry. One of the main challenges is the initial activation of the methane molecule. In this thesis, heterogeneous catalysts for two different methane conversion processes are investigated. Firstly, the deactivation of supported Ni catalysts during the dry reforming of methane is studied. Secondly, the applicability of Metal-Organic Frameworks in the selective partial oxidation of methane to methanol is evaluated. Methane ; Catalysis ; Chemistry ; Methanol ; Raw material ; Partial oxidation ; Anaerobic oxidation of methane ; Methane reformer ; Environmental chemistry ; Inorganic chemistry ; Organic chemistry ; Steam reforming ; Hydrogen production Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions ; Catalysts for Methane Reforming
Authors: Alan Edlund
Source: Digital Commons - USU (Utah State University) (article, 2021-10-08)
Field: Materials Science — Biomaterials

Synthetic Spider Silk Sustainability Verification by Techno-Economic and Life Cycle Analysis Major ampullate spider silk represents a promising biomaterial with diverse commercial potential ranging from textiles to medical devices due to the excellent physical and thermal properties from the protein structure. Recent advancements in synthetic biology have facilitated the development of recombinant spider silk proteins from Escherichia coli (E. coli), alfalfa, and goats. This study specifically investigates the economic feasibility and environmental impact of synthetic spider silk manufacturing. Pilot scale data was used to validate an engineering process model that includes all of the required sub-processing steps for synthetic fiber manufacture: production, harvesting, purification, drying, and spinning. Modeling was constructed modularly to support assessment of alternative protein production methods (alfalfa and goats) as well as alternative down-stream processing technologies. The techno-economic analysis indicates a minimum sale price from pioneer and optimized E. coli plants at $761 kg-1 and $23 kg-1 with greenhouse gas emissions of 572 kg CO2-eq. kg-1 and 55 kg CO2-eq. kg-1, respectively. Spider silk sale price estimates from goat pioneer and optimized results are $730 kg-1 and $54 kg-1, respectively, with pioneer and optimized alfalfa plants are $207 kg-1 and $9.22 kg-1 respectively. Elevated costs and emissions from the pioneer plant can be directly tied to the high material consumption and low protein yield. Decreased production costs associated with the optimized plants include improved protein yield, process optimization, and an Nth plant assumption. Discussion focuses on the commercial potential of spider silk, the production performance requirements for commercialization, and impact of alternative technologies on the sustainability of the system. Spider silk ; SILK ; Sustainability ; Spider ; Economic analysis ; Business ; Computer science ; Economics ; Agricultural economics ; Telecommunications ; Biology ; Ecology Silk-based biomaterials and applications ; Silkworms and Sericulture Research
Authors: Kun Wang
Source: arXiv (Cornell University) (preprint, 2021-07-05)
Field: Materials Science — Materials Chemistry

Development of the modified quasichemical model in the distinguishable-pair approximation for multiple compositions of short-range ordering A binary solution with short-range ordering (SRO) exhibits characteristic solution thermodynamics. The Modified Quasichemical Model in the Pair Approximation (MQMPA) can effectively capture the thermodynamic features of a binary solution with a onefold SRO. However, once the SRO occurs at multiple compositions in a binary solution, the MQMPA is in principle inconvenient to treat the solution thermodynamics. It usually requires a large number of model parameters to fit the thermodynamic data of such a solution. The present work proposes the Modified Quasichemical Model in the Distinguishable-Pair Approximation (MQMDPA), which is a further improvement of the MQMPA. The MQMDPA can more realistically describe the solution thermodynamics with manifold SROs using fewer model parameters. It benefits from grouping the ordered pairs, which were assumed to be indistinguishable within the MQMPA, into several distinguishable types. Each kind of ordered pair has unique coordination numbers and pair energy, which is responsible for describing one of the SROs at the desired composition and strength. Interestingly, the MQMDPA can be completely transformed into the MQMPA when all kinds of ordered pairs are assigned the same pair energy and coordination numbers. The distinguishable pairs have thus become indistinguishable. Several real liquids with at least two observed SROs were successfully treated by the MQMDPA to demonstrate its effectiveness and reliability. Binary number ; Range (aeronautics) ; Thermodynamics ; Work (physics) ; Statistical physics ; Energy (signal processing) ; Physics ; Materials science ; Mathematics ; Quantum mechanics X-ray Diffraction in Crystallography ; Zeolite Catalysis and Synthesis ; Advanced Chemical Physics Studies
Authors: Wei Zhang | Minghao Liu | Jun Chen | Hao Wang
Source: Interdisciplinary Research in Medical Sciences Specialty (article, 2021-01-01)
Field: Materials Science — Biomaterials

Solvent-Dependent Morphology and Properties of Electrospun Poly(2-ethyl-2-oxazoline) Nanofibrous Scaffolds for Tissue Engineering Choosing an appropriate biomaterial is crucial when designing scaffolds intended for biomedical use. In particular, creating nanofibrous architectures by electrospinning requires careful selection of the polymer. Poly (2-ethyl-2-oxazoline) (PEOX) is one such candidate polymer suitable for electrospinning and can be utilized to fabricate scaffolds for medical purposes. PEOX dissolves readily in water, which is a significant advantage for biological systems, and it also exhibits solubility in vari Electrospinning ; Tissue engineering ; Biomaterial ; Nanofiber ; Polymer ; Morphology (biology) Electrospun Nanofibers in Biomedical Applications ; Conducting polymers and applications ; Advanced Cellulose Research Studies
Authors: Chauncey Tucker
Source: Digital Commons - USU (Utah State University) (article, 2021-10-05)
Field: Materials Science — Biomaterials

Mechanical and Physical Properties of Spider Silk Films Made from Organic and Water-Based Dopes In this project, we focus on developing a method to produce synthetic spider silk thin films. Using these films we optimized mechanical properties, lowered cost, and improved the environmental impact using different processing methods. Applications for spider silk films are broad, ranging from physical protection to biocompatible materials. This project was designed to improve mechanical properties and production methods of films made from synthetic forms of MaSp1 and MaSp2 from the dragline silk of Nephila clavipes. We have increased the mechanical stress (200 MPa) to more than 4 times that of similar products with elongations as high as 35%. The films have also been analyzed using NMR, XRD, and AFM or SEM showing that the secondary structure in as-poured films is mainly alpha-helical and after processing this structure turns to an aligned betasheet formation similar to that in spider silk fibers. Spider silk ; SILK ; Spider ; Polymer science ; Materials science ; Composite material ; Ecology ; Biology Silk-based biomaterials and applications ; Silkworms and Sericulture Research
Authors: K. A. Vanalkar
Source: International Journal for Research in Applied Science and Engineering Technology (article, 2021-04-19)
Field: Materials Science — Polymers and Plastics

An Overview of Shrink Wrapping Machine for Wrapping of Cloth Peg In order to handle most of the products like cloth peg, container, hanger, tooth brush, shaving blades, heavy duty cell etc. shrink wrapping machine is universally used. By shrink wrapping of the products, it is possible to handle the products conveniently, it make the packing attractive, it is very convenient during transport also. Here an attempt is made to present a structured approach for design and development of shrink wrapping machine used for cloth peg wrapping. The main component of machine is rollers, chain drive, geared d.c.motor, heater, structure. PEG ratio ; Computer science ; Engineering drawing ; Polymer science ; Materials science ; Engineering ; Business Textile materials and evaluations
Authors: David R. Khan
Source: Biomedical Journal of Scientific & Technical Research (article, 2021-10-07)
Field: Materials Science — Biomaterials

"Recently Reported Dual-Drug Co-Delivery of Liposomal-Based Chemotherapeutics to Treat Breast Cancer" The use of nanocarriers such as liposomes to co-encapsulate more than one anticancer drug has been shown to be a promising strategy in cancer treatment with respect to overcoming multidrug resistance (MDR). This is in part not only due to the many advantages associated with the use of liposomes, but also the effectiveness of using this dual-drug strategy to overcome potential drug resistance when compared to a single chemotherapeutic. In this review, we report promising recently reported dualdrug co-delivery of liposomal-based chemotherapeutics in order to treat breast cancer and provide some perspectives on possible future constructs. Breast cancer ; Library science ; Drug delivery ; Medicine ; Internal medicine ; Oncology ; Cancer ; Nanotechnology ; Computer science ; Materials science Nanoparticle-Based Drug Delivery ; Nanoplatforms for cancer theranostics ; Graphene and Nanomaterials Applications
Authors: Sergio A. Urzúa | Perla Y. Sauceda-Oloño | Carlos D. García | Christopher D. Cooper
Source: arXiv (Cornell University) (preprint, 2021-12-10)
Field: Materials Science — Surfaces, Coatings and Films

Predicting the orientation of adsorbed proteins steered with electric fields using a simple electrostatic model Under the most common experimental conditions, the adsorption of proteins to solid surfaces is an spontaneous process that leads to a rather compact layer of randomly oriented molecules. Due to the importance of this process for the development of catalytic surfaces, a number of existing computational and experimental approaches try to predict and control the orientation of such molecules. However, and despite their own advantages, these tend to be either too expensive computationally, or oversimplified, undermining their ability to predict the most appropriate experimental conditions to maximize the catalytic activity of adsorbed proteins. To address this current need, we present an efficient computational approach to model the behavior of proteins near surfaces in the presence of an external electric field, based on continuum electrostatics. Our model can not only estimate the overall affinity of the protein with the surface, but also their most likely orientation as a function of the potential applied. In this way, a rational selection of the potential can be performed to maximize the accessibility of the protein's active site to the solvent. The model relies on the Poisson-Boltzmann equation and was implemented in an extension of the code PyGBe that includes an external electric field, and renders the electrostatic component of the solvation free energy. To demonstrate the feasibility of this technique, we investigate the adsorption of trypsin onto a carbon electrode under potentiostatic conditions both numerically and experimentally. We found that even though the adsorption process is largely dominated by hydrophobic effects, the orientation of trypsin can be controlled through an external potential, influencing the position of the active sites, and resulting in an important change in the catalytic activity of the surface. Electrostatics ; Adsorption ; Electric field ; Static electricity ; Solvation ; Orientation (vector space) ; Chemical physics ; Poisson–Boltzmann equation ; Electric potential energy ; Chemistry ; Molecule ; Biological system ; Materials science ; Physics ; Energy (signal processing) ; Ion ; Physical chemistry ; Organic chemistry ; Mathematics Polymer Surface Interaction Studies ; Microfluidic and Bio-sensing Technologies ; Microfluidic and Capillary Electrophoresis Applications
Authors: Rikuo Kajiwara | Koji Hirano | Masahiro Miura
Source: Chemistry Letters (article, 2021-08-17)
Field: Chemistry — Organic Chemistry

Copper-mediated Regioselective C–H Cyanation of Phenols with Assistance of Bipyridine-type Bidentate Auxiliary Abstract A Cu-mediated ortho-selective C–H cyanation of phenols with ethyl cyanoformate as the cyano source has been developed. The key to success is the introduction of 4,4′-di-tert-butyl-2,2′-bipyridine (dtbpy) bidentate auxiliary on the phenol oxygen, which is easily attachable, detachable, and recyclable. The newly developed protocol is tolerant of several carbonyl functional groups, which are incompatible with previous Lewis-acid-promoted cyanation of phenols. Cyanation ; Chemistry ; Phenols ; Denticity ; Phenol ; Regioselectivity ; Bipyridine ; Organic chemistry ; Medicinal chemistry ; Catalysis ; Metal ; Crystal structure Catalytic C–H Functionalization Methods ; Synthesis and Catalytic Reactions ; Sulfur-Based Synthesis Techniques
Authors: István Antal
Source: Acta Pharmaceutica Hungarica (article, 2021-11-15)
Field: Materials Science — Biomaterials

Advanced Drug Delivery Systems: From Nano- and Microparticles to Smart Pills Pill ; Drug delivery ; Drug ; Nano- ; Medicine ; Nanotechnology ; Pharmacology ; Materials science Nanoparticle-Based Drug Delivery ; Innovative Microfluidic and Catalytic Techniques Innovation ; Advanced Drug Delivery Systems
Authors: Indrajit Tah | Smarajit Karmakar
Source: arXiv (Cornell University) (preprint, 2021-08-05)
Field: Materials Science — Materials Chemistry

Kinetic Fragility Directly Correlates with the Many-body Static Amorphous Order in Glass-Forming Liquids The term "fragility" describes the rate at which viscosity grows when a supercooled liquid approaches its putative glass transition temperature. The field of glassy materials is actively searching for a structural origin that governs this dynamical slowing down in the supercooled liquid, which occurs without any discernible change in structure. Our work shows clear evidence that growing many-body static amorphous order is intimately correlated with the kinetic fragility of glass-forming liquids. It confirms that the system's dynamical response to temperature is concealed in its micro-structures. This finding may pave the way for a deeper understanding of the different temperature dependence of the relaxation time or viscosity in a wide variety of glass-forming liquids. Fragility ; Supercooling ; Glass transition ; Viscosity ; Amorphous solid ; Relaxation (psychology) ; Kinetic energy ; Materials science ; Thermodynamics ; Viscous liquid ; Chemical physics ; Dynamical heterogeneity ; Chemistry ; Physics ; Composite material ; Polymer ; Classical mechanics ; Crystallography Material Dynamics and Properties ; Glass properties and applications ; Liquid Crystal Research Advancements
Authors: Vilmos Kertész | John F. Cahill | Bernadeta Srijanto | C. Patrick Collier | Marissa Vavrek | Bingming Chen
Source: Rapid Communications in Mass Spectrometry (article, 2021-09-20)
Field: Chemistry — Spectroscopy

Integrated laser ablation‐dropletProbe‐mass spectrometry for absolute drug quantitation, metabolite detection, and distribution in tissue This study exemplifies the capabilities of integrated laser ablation-dropletProbe-mass spectrometry (LADP-MS) for high resolution absolute drug quantitation analysis of thin tissue sections. This capability will be valuable for applications needing to quantitatively understand the spatial distribution of small molecules in tissue. Chemistry ; Mass spectrometry ; Chromatography ; Mass spectrometry imaging ; Laser ablation ; Analytical Chemistry (journal) ; Resolution (logic) ; Parylene ; Laser Mass Spectrometry Techniques and Applications ; Pesticide Residue Analysis and Safety ; Analytical Chemistry and Chromatography
Authors: Liang He | F. Tsui
Source: Carolina Digital Repository (University of North Carolina at Chapel Hill) (article, 2021-07-03)
Field: Materials Science — Materials Chemistry

Techniques for combinatorial molecular beam epitaxy Basic considerations for implementing combinatorial approach to molecular beam epitaxy (MBE) are discussed, focusing on the key issues relevant to conventional MBE synthesis using solid sources and characterization. The primary objective for implementing combinatorial approach is to make MBE do more, more able to carry out controlled and systematic work in large parameter space, without sacrificing any existing capabilities of conventional MBE. Methods for accomplishing this by integrating current instrumentation technology are described. Molecular beam epitaxy ; Materials science ; Computer science ; Epitaxy ; Nanotechnology Porphyrin and Phthalocyanine Chemistry ; Molecular Junctions and Nanostructures ; Laser-Matter Interactions and Applications
Authors: Alex de Oliveira Gomes | Douglas de Souza | Jerônimo da Silva Costa | Vera L. P. Pereira
Source: Journal of the Brazilian Chemical Society (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Ketones as Electrophile in Nitroaldol Reaction: Synthesis of β,β-Disubstituted- 1,3‑dinitroalkanes and Allylic Nitro Compounds β,β-Disubstituted-1,3-dinitro compounds were obtained exclusively with an overall yield of 83% through a domino nitroaldol/elimination/1,4-addition process, when excess nitromethane was added to cyclohexanone or butanone using DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), as a basic catalyst. On the other hand, β-nitroalcohols could be obtained in 30-84% yield, when nitromethane reacts with different aliphatic ketones in stoichiometric amounts, in the presence of catalytic amounts of K2CO3(s), Amberlyst®-A21 or TBAF.3H2O (tetra-n-butylammonium fluoride trihydrate)/THF (tetrahydrofuran). In addition, a new and versatile route to obtainment of allylic nitro compounds, by treatment of acetylated nitroalcohols and aldehydes in catalytic amounts of DBU or TBAF.3H2O, via a one-pot elimination/nitroaldol reaction sequence, was developed. Nitromethane ; Cyclohexanone ; Chemistry ; Catalysis ; Allylic rearrangement ; Yield (engineering) ; Nitroaldol reaction ; Tetrahydrofuran ; Organic chemistry ; Electrophile ; Medicinal chemistry ; Nitro ; Enantioselective synthesis ; Solvent Chemical Synthesis and Reactions ; Chemical Reaction Mechanisms ; Nanomaterials for catalytic reactions