jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Kazuhiro Kimura | Masayuki Toyoda | P. Babkevich | Kunihiko Yamauchi | Miyu Sera | Vivian Nassif | H. M. Rønnow | T. Kimura
Source: Physical review. B./Physical review. B (article, 2018-04-18)
Field: Materials Science — Electronic, Optical and Magnetic Materials

<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>A</mml:mi></mml:math>-cation control of magnetoelectric quadrupole order in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>A</mml:mi><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>TiO</mml:mi><mml:mo>)</mml:mo><mml:mi>Cu</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:msub><mml:mi>PO</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:mo>)</mml:mo></mml:mrow><mml:mn>4</mml:mn></mml:msub><mml:mrow><mml:mspace width="0.16em"/><mml:mo>(</mml:mo><mml:mi>A</mml:mi><mml:mo>=</mml:mo><mml:mi>Ba</mml:mi></mml:mrow><mml:mo>,</mml:mo><mml:mtext>Sr</mml:mtext><mml:mo>,</mml:mo><mml:mtext>and Pb</mml:mtext><mml:mo>)</mml:mo></mml:mrow></mml:math> A material with broken space-inversion and time-reversal symmetries can exhibit symmetry-dependent unique phenomena such as the magnetoelectric effect. Ferroic order of magnetic quadrupoles fulfills this symmetry condition. The authors report here the discovery of ferroic magnetic quadrupole order and its magnetoelectric activity in the novel compound Pb(TiO)Cu${}_{4}$(PO${}_{4}$)${}_{4}$, which is in contrast with isostructural Ba(TiO)Cu${}_{4}$(PO${}_{4}$)${}_{4}$ and Sr(TiO)Cu${}_{4}$(PO${}_{4}$)${}_{4}$ in exhibiting antiferroic quadrupole order. Their first-principles calculations reveal that ${s}^{2}$ electrons in Pb${}^{2+}$ ions alter specific magnetic interactions and consequently switch the quadrupole order from antiferroic to ferroic. This result provides not only an opportunity to explore magnetoelectric phenomena arising from magnetic quadrupoles, but also a useful way of fine-tuning magnetic interactions with ${s}^{2}$ electrons. Quadrupole ; Isostructural ; Homogeneous space ; Order (exchange) ; Electron ; Ion ; Symmetry (geometry) ; Physics ; Quadrupole magnet ; Crystallography ; Condensed matter physics ; Atomic physics ; Quantum mechanics ; Mathematics ; Crystal structure ; Chemistry ; Geometry Multiferroics and related materials ; Advanced Condensed Matter Physics ; Ferroelectric and Piezoelectric Materials
Authors: Medha M. Ugru | Sanjana Sheshadri | Devendra Jain | Harishkumar Madhyastha | Radha Madhyastha | Masugi Maruyama | P. N. Navya | Hemant Kumar Daima
Source: Colloids and Surfaces A Physicochemical and Engineering Aspects (article, 2018-03-26)
Field: Materials Science — Materials Chemistry

Insight into the composition and surface corona reliant biological behaviour of quercetin engineered nanoparticles Nanoparticle ; Quercetin ; Chemistry ; Nanotechnology ; Reactive oxygen species ; Colloidal gold ; Biophysics ; Biomolecule ; Materials science ; Biochemistry ; Antioxidant ; Biology Nanoparticles: synthesis and applications ; Nanoparticle-Based Drug Delivery ; Graphene and Nanomaterials Applications
Authors: Yuya Tamura | Kyohei Kanomata | Takuya Kitaoka
Source: Scientific Reports (article, 2018-03-22)
Field: Materials Science — Biomaterials

Interfacial Hydrolysis of Acetals on Protonated TEMPO-oxidized Cellulose Nanofibers Abstract 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNs), which have a high-density of exposed carboxylic acid groups on their crystalline surfaces, effectively act as acid catalysts in acetal hydrolysis. Carboxy-free cellulose nanofibers, polymeric carboxylic acids, and homogeneous acetic acid do not show significant catalytic activity under the same reaction conditions. Mercerized TOCNs differing from the original TOCNs in a crystalline structure were also ineffective, which suggests that the unique nanoarchitectural features of TOCNs, such as regularly aligned carboxylic acid groups, large specific surface areas, and structural rigidity, must be major factors in the acceleration of acetal hydrolysis. Kinetic analysis suggested that substrates and/or acid catalyst species were concentrated on the TOCN crystalline surfaces, which significantly enhanced the catalytic activity. Acetal ; Hydrolysis ; Cellulose ; Nanofiber ; Catalysis ; Acetic acid ; Carboxylic acid ; Protonation ; Chemistry ; Acid catalysis ; Polymer chemistry ; Organic chemistry ; Homogeneous ; Materials science ; Chemical engineering ; Composite material Advanced Cellulose Research Studies ; Nanomaterials for catalytic reactions ; Catalysis for Biomass Conversion
Authors: Febriyani Damanik | Gabriele Spadolini | Joris I. Rotmans | Silvia Farè | Lorenzo Moroni
Source: Biomaterials Science (article, 2018-12-21)
Field: Materials Science — Biomaterials

Biological activity of human mesenchymal stromal cells on polymeric electrospun scaffolds Electrospinning provides a simple robust method to manufacture scaffolds for tissue engineering applications. Though varieties of materials can be used, optimization and biocompatibility tests are required to provide functional tissue regeneration. Moreover, many studies are limited to 2D electrospun constructs rather than 3D templates due to the production of high density packed fibres, which result in poor cell infiltration. Here, we optimised electrospinning parameters for three different polymers: poly(ε-caprolactone) (PCL), polylactic acid (PLA) and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PA) copolymers. Human mesenchymal stromal cells (hMSCs) were cultured on scaffolds for 14 days to study the scaffolds' biocompatibility and their multi-lineage differentiation potential or maintenance of stemness in the absence of chemical stimuli. For all scaffolds, a high and stable metabolic activity was measured throughout the culture time with a high proliferation rate compared to day 1 (PCL 5.8-, PLA 4-, PA 4.9-fold). The metabolism of hMSCs was also measured through glucose and lactate concentrations, showing no cytotoxic levels up to 14 days. Total glycosaminoglycan (GAG) production was the highest in PA electrospun scaffolds. When normalized to DNA, GAG production was the highest in PLA and PA scaffolds. All scaffolds were prone to differentiate to an osteogenic lineage, with PCL providing the highest alkaline phosphatase and collagen type Ia gene upregulation. As PA had the most stable fibre formation, it was chosen as a template to further incorporate stromal cell-derived factor-1 (SDF-1) and granulocyte colony-stimulating factor (G-CSF), and stimulate higher hMSC infiltration. These scaffolds provided significantly higher hMSC infiltration than normal PA scaffolds. In conclusion, our optimized biocompatible electrospun scaffolds have shown promising regulation of hMSC fate. When combined with migratory stimulating cytokines, these scaffolds may overcome the known challenges of poor cellular infiltration typical of micro- and nano-fibrillary random meshes. Mesenchymal stem cell ; Chemistry ; Stromal cell ; Electrospinning ; Cell biology ; Polymer ; Biology ; Cancer research ; Organic chemistry Electrospun Nanofibers in Biomedical Applications ; Tissue Engineering and Regenerative Medicine ; Mesenchymal stem cell research
Authors: Sergio Martín‐Saldaña | Merari Tumin Chevalier | Marı́a José Iglesias | Silvana Lorena Colman | Claudia A. Casalongué | Vera A. Álvarez | Alberto Antonio Chevalier
Source: Carbohydrate Polymers (article, 2018-08-06)
Field: Materials Science — Biomaterials

Salicylic acid loaded chitosan microparticles applied to lettuce seedlings: Recycling shrimp fishing industry waste Salicylic acid ; Chitosan ; Shrimp ; Chemistry ; Fishing ; Food science ; Botany ; Biotechnology ; Biochemistry ; Biology ; Fishery Nanocomposite Films for Food Packaging ; Plant Growth Enhancement Techniques ; Polymer-Based Agricultural Enhancements
Authors: Matthew J. Cliffe | Jeongjae Lee | Joseph A. M. Paddison | Sam Schott | Paromita Mukherjee | Michael W. Gaultois | Pascal Manuel | Henning Sirringhaus | Siân E. Dutton | Clare P. Grey
Source: Physical review. B./Physical review. B (article, 2018-04-25)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Low-dimensional quantum magnetism in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Cu</mml:mi><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mi>NCS</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:mn>2</mml:mn></mml:msub></mml:math>: A molecular framework material Low-dimensional magnetic materials with spin-$\frac{1}{2}$ moments can host a range of exotic magnetic phenomena due to the intrinsic importance of quantum fluctuations to their behavior. Here, we report the structure, magnetic structure, and magnetic properties of copper ii thiocyanate, ${\mathrm{Cu}(\mathrm{NCS})}_{2}$, a one-dimensional coordination polymer which displays low-dimensional quantum magnetism. Magnetic susceptibility, electron paramagnetic resonance spectroscopy, $^{13}\mathrm{C}$ magic-angle spinning nuclear magnetic resonance spectroscopy, and density functional theory investigations indicate that ${\mathrm{Cu}(\mathrm{NCS})}_{2}$ behaves as a two-dimensional array of weakly coupled antiferromagnetic spin chains $[{J}_{2}=133(1)\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, $\ensuremath{\alpha}={J}_{1}/{J}_{2}=0.08]$. Powder neutron-diffraction measurements confirm that ${\mathrm{Cu}(\mathrm{NCS})}_{2}$ orders as a commensurate antiferromagnet below ${T}_{\mathrm{N}}=12\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, with a strongly reduced ordered moment ($0.3{\ensuremath{\mu}}_{\mathrm{B}}$) due to quantum fluctuations. Antiferromagnetism ; Magnetism ; Physics ; Magnetic moment ; Crystallography ; Paramagnetism ; Condensed matter physics ; Mott insulator ; Electron paramagnetic resonance ; Spectroscopy ; Nuclear magnetic resonance ; Chemistry ; Quantum mechanics Magnetism in coordination complexes ; Organic and Molecular Conductors Research ; Metal-Organic Frameworks: Synthesis and Applications
Authors: José Luís Dores‐Sousa | Jelle De Vos | Sebastiaan Eeltink
Source: Journal of Separation Science (review, 2018-09-22)
Field: Chemistry — Spectroscopy

Resolving power in liquid chromatography: A trade‐off between efficiency and analysis time This review describes chromatographic dispersion and different plate-height models frequently used to assess the chromatographic performance of ultra-high-pressure liquid chromatography column technology. Furthermore, different performance indices, including the resolution, the separation impedance, and kinetic plots are discussed allowing to quantify and visualize the resolving power in liquid chromatography. The construction of kinetic plots is explained, and different visualization approaches are highlighted. Finally, key instrument and column-technology developments to advance the kinetic performance limits are discussed and selected state-of-the-art applications are highlighted. Chromatography ; Dispersion (optics) ; Visualization ; High-performance liquid chromatography ; Resolution (logic) ; Column (typography) ; Chemistry ; Kinetic energy ; Analytical Chemistry (journal) ; Process engineering ; Computer science ; Data mining ; Engineering ; Artificial intelligence ; Physics ; Optics Analytical Chemistry and Chromatography ; Microfluidic and Capillary Electrophoresis Applications ; Protein purification and stability
Authors: Renée Duijvelshoff | Nicole C. A. van Engeland | Karen Gabriels | Serge H. M. Söntjens | Anthal I.P.M. Smits | Patricia Y. W. Dankers | Carlijn V. C. Bouten
Source: Bioengineering (article, 2018-08-06)
Field: Materials Science — Biomaterials

Host Response and Neo-Tissue Development during Resorption of a Fast Degrading Supramolecular Electrospun Arterial Scaffold In situ vascular tissue engineering aims to regenerate vessels "at the target site" using synthetic scaffolds that are capable of inducing endogenous regeneration. Critical to the success of this approach is a fine balance between functional neo-tissue formation and scaffold degradation. Circulating immune cells are important regulators of this process as they drive the host response to the scaffold and they play a central role in scaffold resorption. Despite the progress made with synthetic scaffolds, little is known about the host response and neo-tissue development during and after scaffold resorption. In this study, we designed a fast-degrading biodegradable supramolecular scaffold for arterial applications and evaluated this development in vivo. Bisurea-modified polycaprolactone (PCL2000-U4U) was electrospun in tubular scaffolds and shielded by non-degradable expanded polytetrafluoroethylene in order to restrict transmural and transanastomotic cell ingrowth. In addition, this shield prevented graft failure, permitting the study of neo-tissue and host response development after degradation. Scaffolds were implanted in 60 healthy male Lewis rats as an interposition graft into the abdominal aorta and explanted at different time points up to 56 days after implantation to monitor sequential cell infiltration, differentiation, and tissue formation in the scaffold. Endogenous tissue formation started with an acute immune response, followed by a dominant presence of pro-inflammatory macrophages during the first 28 days. Next, a shift towards tissue-producing cells was observed, with a striking increase in α-Smooth Muscle Actin-positive cells and extracellular matrix by day 56. At that time, the scaffold was resorbed and immune markers were low. These results suggest that neo-tissue formation was still in progress, while the host response became quiescent, favoring a regenerative tissue outcome. Future studies should confirm long-term tissue homeostasis, but require the strengthening of the supramolecular scaffold if a non-shielded model will be used. Scaffold ; Resorption ; Tissue engineering ; Materials science ; Biomedical engineering ; Medicine ; Internal medicine Electrospun Nanofibers in Biomedical Applications ; Supramolecular Self-Assembly in Materials ; Bone Tissue Engineering Materials
Authors: Kodai Hara | Masayuki Uchida | Risa Tagata | Hideshi Yokoyama | Yoshinobu Ishikawa | Asami Hishiki | Hiroshi Hashimoto
Source: Acta Crystallographica Section F Structural Biology Communications (article, 2018-03-22)
Field: Materials Science — Materials Chemistry

Structure of proliferating cell nuclear antigen (PCNA) bound to an APIM peptide reveals the universality of PCNA interaction Proliferating cell nuclear antigen (PCNA) provides a molecular platform for numerous protein-protein interactions in DNA metabolism. A large number of proteins associated with PCNA have a well characterized sequence termed the PCNA-interacting protein box motif (PIPM). Another PCNA-interacting sequence termed the AlkB homologue 2 PCNA-interacting motif (APIM), comprising the five consensus residues (K/R)-(F/Y/W)-(L/I/V/A)-(L/I/V/A)-(K/R), has also been identified in various proteins. In contrast to that with PIPM, the PCNA-APIM interaction is less well understood. Here, the crystal structure of PCNA bound to a peptide carrying an APIM consensus sequence, RFLVK, was determined and structure-based interaction analysis was performed. The APIM peptide binds to the PIPM-binding pocket on PCNA in a similar way to PIPM. The phenylalanine and leucine residues within the APIM consensus sequence and a hydrophobic residue that precedes the APIM consensus sequence are crucially involved in interactions with the hydrophobic pocket of PCNA. This interaction is essential for overall binding. These results provide a structural basis for regulation of the PCNA interaction and might aid in the development of specific inhibitors of this interaction. Proliferating cell nuclear antigen ; Peptide ; Protein–protein interaction ; DNA ; Biology ; Molecular biology ; Biochemistry Enzyme Structure and Function ; DNA Repair Mechanisms ; Protein Structure and Dynamics
Authors: Helen Y. Playford | Thomas F. Whale | Benjamin J. Murray | Matthew G. Tucker | Christoph G. Salzmann
Source: Journal of Applied Crystallography (article, 2018-07-26)
Field: Materials Science — Materials Chemistry

Analysis of stacking disorder in ice I using pair distribution functions Stacking-disordered materials display crystalline order in two dimensions but are disordered along the direction in which layered structural motifs are stacked. Countless examples of stacking disorder exist, ranging from close-packed metals, ice I and diamond to open-framework materials and small-molecule pharmaceuticals. In general, the presence of stacking disorder can have profound consequences for the physical and chemical properties of a material. Traditional analyses of powder diffraction data are often complicated by the presence of memory effects in the stacking sequences. Here it is shown that experimental pair distribution functions of stacking-disordered ice I can be used to determine local information on the fractions of cubic and hexagonal stacking. Ice is a particularly challenging material in this respect, since both the stacking disorder and the orientational disorder of the water molecules need to be described. Memory effects are found to contribute very little to the pair distribution functions, and consequently, the analysis of pair distribution functions is the method of choice for characterizing stacking-disordered samples with complicated and high-order memory effects. In the context of this work, the limitations of current structure-reconstruction approaches are also discussed. Stacking ; Materials science ; Context (archaeology) ; Molecule ; Crystallography ; Crystal structure ; Chemical physics ; Condensed matter physics ; Chemistry ; Physics ; Geology ; Nuclear magnetic resonance X-ray Diffraction in Crystallography ; Advanced NMR Techniques and Applications ; Crystallography and molecular interactions
Authors: Faisal Nadeem | Julien Mandon | Amir Khodabakhsh | Simona M. Cristescu | Frans J. M. Harren
Source: Sensors (article, 2018-06-27)
Field: Chemistry — Spectroscopy

Sensitive Spectroscopy of Acetone Using a Widely Tunable External-Cavity Quantum Cascade Laser We employed a single-mode, widely tunable (~300 cm<sup>&minus;1</sup>) external-cavity quantum cascade laser operating around 8 &micro;m for broadband direct absorption spectroscopy and wavelength modulation spectroscopy where a modulation frequency of 50 kHz was employed with high modulation amplitudes of up to 10 GHz. Using a compact multipass cell, we measured the entire molecular absorption band of acetone at ~7.4 &micro;m with a spectral resolution of ~1 cm<sup>&minus;1</sup>. In addition, to demonstrate the high modulation dynamic range of the laser, we performed direct absorption (DAS) and second harmonic wavelength modulation spectroscopy (WMS-2f) of the Q-branch peak of acetone molecular absorption band (HWHM ~10 GHz) near 1365 cm<sup>&minus;1</sup>. With WMS-2f, a minimum detection limit of 15 ppbv in less than 10 s is achieved, which yields a noise equivalent absorption sensitivity of 1.9 &times; 10<sup>&minus;8</sup> cm<sup>&minus;1</sup> Hz<sup>&minus;1/2</sup>. Quantum cascade laser ; Absorption spectroscopy ; Spectroscopy ; Laser ; Absorption (acoustics) ; Modulation (music) ; Tunable diode laser absorption spectroscopy ; Amplitude modulation ; Materials science ; Optics ; Cascade ; Analytical Chemistry (journal) ; Optoelectronics ; Chemistry ; Frequency modulation ; Tunable laser ; Physics ; Telecommunications ; Radio frequency Spectroscopy and Laser Applications ; Atmospheric Ozone and Climate ; Laser Design and Applications
Authors: Marc Kassis | Edward Wishnow | Michael Raffanti | Yuzo Ishikawa | Ean James | Elisha Jhoti | Kyle Lanclos | Scott Lilley | Tim Miller | Steve Milner | Tom Payne | Kodi Rider | Constance M. Rockosi | William Deich | S. L. Allen | David Cowley | Dale Sandford | Christian Schwab | Martin M. Sirk | R. E. Smith | Marie Weisfeiler | M. K. Wilcox | Adam Vandenberg | Steven R. Gibson | Andrew W. Howard | Jerry Edelstein | Arpita Roy | Chris Smith | Samuel Halverson | Jason Chin | James M. Curtis | D. Finstad | David W. Coutts | Andreas Seifahrt | Tobias Feger | Julian Stuermer | Yulia V. Gurevich | Peter Wizinowich
Source: Ground-based and Airborne Instrumentation for Astronomy VII (article, 2018-07-06)
Field: Chemistry — Spectroscopy

Keck Planet Finder: preliminary design The Keck Planet Finder (KPF) is a fiber-fed, high-resolution, high-stability spectrometer in development for the W.M. Keck Observatory. The instrument recently passed its preliminary design review and is currently in the detailed design phase. KPF is designed to characterize exoplanets using Doppler spectroscopy with a single measurement precision of 0.5 m s<sup>−1</sup> or better; however, its resolution and stability will enable a wide variety of other astrophysical pursuits. KPF will have a 200 mm collimated beam diameter and a resolving power greater than 80,000. The design includes a green channel (445 nm to 600 nm) and red channel (600 nm to 870 nm). A novel design aspect of KPF is the use of a Zerodur optical bench, and Zerodur optics with integral mounts, to provide stability against thermal expansion and contraction effects. Exoplanet ; Optics ; Planet ; Collimated light ; Spectrometer ; Observatory ; Interferometry ; Physics ; Remote sensing ; Astronomy ; Laser ; Geology Spectroscopy and Laser Applications ; Advanced Fiber Laser Technologies ; Laser-Matter Interactions and Applications
Authors: Niklas W. A. Gebauer | Michael Gastegger | Kristof T. Schütt
Source: arXiv (Cornell University) (preprint, 2018-10-26)
Field: Materials Science — Materials Chemistry

Generating equilibrium molecules with deep neural networks Discovery of atomistic systems with desirable properties is a major challenge in chemistry and material science. Here we introduce a novel, autoregressive, convolutional deep neural network architecture that generates molecular equilibrium structures by sequentially placing atoms in three-dimensional space. The model estimates the joint probability over molecular configurations with tractable conditional probabilities which only depend on distances between atoms and their nuclear charges. It combines concepts from state-of-the-art atomistic neural networks with auto-regressive generative models for images and speech. We demonstrate that the architecture is capable of generating molecules close to equilibrium for constitutional isomers of C$_7$O$_2$H$_{10}$. Artificial neural network ; Deep neural networks ; Artificial intelligence ; Computer science ; Statistical physics ; Mathematical economics ; Economics ; Physics Machine Learning in Materials Science ; Computational Drug Discovery Methods ; Innovative Microfluidic and Catalytic Techniques Innovation
Authors: Vincent Blay | Toshiyuki Yokoi | Humberto González‐Díaz
Source: Journal of Chemical Information and Modeling (article, 2018-08-23)
Field: Chemistry — Inorganic Chemistry

Perturbation Theory–Machine Learning Study of Zeolite Materials Desilication Zeolites are important materials for research and industrial applications. Mesopores are often introduced by desilication but other properties are also affected, making its optimization difficult. In this work, we demonstrate that Perturbation Theory and Machine Learning can be combined in a PTML multioutput model describing the effects of desilication. The PTML model achieves a notable accuracy ( R<sup>2</sup> = 0.98) in the external validation and can be useful for the rational design of novel materials. Zeolite ; Chemical engineering ; Computer science ; Chemistry ; Materials science ; Engineering ; Catalysis ; Organic chemistry Zeolite Catalysis and Synthesis ; Advanced Data Processing Techniques ; Advanced NMR Techniques and Applications