jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Chao Zheng | Yue Yu | Shi Kuang | Biyue Zhu | Heng Zhou | Shaoqing Zhang | Jing Yang | Liang Shi | Chongzhao Ran
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2020-10-05)
Field: Materials Science — Materials Chemistry

β-Amyloid peptides tailor switching behaviors of Donor-Acceptor Stenhouse Adducts Abstract Molecular switching plays a critical role in biological and displaying systems. Here we demonstrate the first use of peptides to operate molecular switches of donor-acceptor Stenhouse adducts (DASAs), a series of negative photochromes that are highly promising for applications ranging from smart material to biological systems. Fluorescence imaging proved Aβ40 species could make SHA-2 more stable in the linear configuration than without peptide and decrease the rate of molecular switching. According to molecular dynamics simulation, SHA-2 bound to protein resulted in substantial changes in the tertiary structure of Aβ40 monomer with the region of Glu22-Ala30 partially unfolded and being more exposed to water. This structural change is likely to impede the aggregation of Aβ40, as evidenced by fluorescence and ProteoStat ® aggresome detection experiments. SHA-2 is able to inhibit the aggregation of Aβ40 by producing the off-pathway structures. These results open ample opportunities for optically addressable potential widely apply DASAs in the biological system based on this peptides-tailor process. Aggresome ; Monomer ; Fluorescence ; Molecular dynamics ; Chemistry ; Acceptor ; Peptide ; Biophysics ; Adduct ; Molecular switch ; Amyloid (mycology) ; Combinatorial chemistry ; Nanotechnology ; Molecule ; Materials science ; Biochemistry ; Computational chemistry ; Organic chemistry ; Polymer ; Biology ; Gene Photochromic and Fluorescence Chemistry ; Photoreceptor and optogenetics research ; Neurobiology and Insect Physiology Research
Authors: Oliver G. Hayes | Stewart J. Warrender | David B. Cordes | Morven J. Duncan | Alexandra M. Z. Slawin | Russell E. Morris
Source: European Journal of Inorganic Chemistry (article, 2020-05-27)
Field: Chemistry — Inorganic Chemistry

Preventing Undesirable Structure Flexibility in Pyromellitate Metal Organic Frameworks Removal of coordinated water molecules from the porous Zn‐pyromellitate metal organic framework Zn 5 (OH) 2 (PMA) 2 (H 2 O) 4 · x H 2 O (PMA = pyromellitic acid or 1,2,4,5‐benzene tetracarboxylic acid) should generate coordinatively unsaturated metal sites suitable for gas adsorption. However, reports of instability towards dehydration have restricted the study and utility of this MOF. Here we examine in more detail the nature of the structural transformation that occurs upon dehydration. This study reveals that a fully reversible crystalline‐crystalline transformation from a porous to a non‐porous homologue takes place, proceeding through a partially dehydrated intermediate. We show that doping the structure with Ni 2+ ions at greater than 30 % prevents structural rearrangement, thereby maintaining porosity, and rendering the material effective for gas (nitric oxide) adsorption applications. These results indicate that doping can be an effective means to increase the utility of otherwise unserviceable structures. Chemistry ; Porosity ; Adsorption ; Metal-organic framework ; Molecule ; Oxide ; Benzene ; Metal ; Inorganic chemistry ; Dehydration ; Doping ; Chemical engineering ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Enhanced Oil Recovery Techniques ; Hydrocarbon exploration and reservoir analysis
Authors: Masooma Ibrahim | Thomas Rudszuck | Banan Kerdi | S. Krämer | Gisela Guthausen | Annie K. Powell
Source: Applied Magnetic Resonance (article, 2020-10-08)
Field: Materials Science — Materials Chemistry

Comparative NMR Relaxivity Study of Polyoxometalate-Based Clusters [Mn4(H2O)2(P2W1SO56)2]16− and [{Dy(H2O)6}2Mn4(H2O)2(P2W15O56)2]10− from 20 MHz to 1.2 GHz Abstract Nuclear Magnetic Resonance relaxivities are a measure for the sensitivity of a contrast agent (CA), i.e. the potential of a paramagnetic moiety to enhance longitudinal and transverse relaxation of molecules in its near neighbourhood. The underlying mechanism is called Paramagnetic Relaxation Enhancement (PRE). The relaxivity, characterizing PRE, depends not only on the external applied magnetic field but also depends on numerous factors, such as number of coordinated water molecules, water exchange rate, rotational diffusion, first and second coordination hydration sphere, electronic and magnetic properties of paramagnetic centers and the molecular shape/size of the CA. Relaxation rates are usually normalized to the concentration of the contrast agent to provide the relaxivities. To investigate the influence of these factors on PRE of newly synthesized potential CA, two paramagnetic metals containing polyoxometalates (POMs) [Mn 4 (H 2 O) 2 (P 2 W 15 O 56 ) 2 ] 16− ( Mn 4 -P 2 W 15 ) and [{Dy(H 2 O) 6 } 2 Mn 4 (H 2 O) 2 (P 2 W 15 O 56 ) 2 ] 10− ( Dy 2 Mn 4 -P 2 W 15 ) were selected as models to be studied at 1 H Larmor frequencies from 20 MHz to 1.2 GHz. Structurally, the POM Dy 2 Mn 4 -P 2 W 15 is similar to the tetra-nuclear manganese(II)-substituted sandwich-type POM Mn 4 -P 2 W 15 , with the two coordinated Dy III cations acting as linkers connecting Mn 4 -P 2 W 15 units, thus forming a 1D ladder-like chain structure based on sandwich-type rungs strung together by the dysprosium cations. This study shows that POM ( Dy 2 Mn 4 -P 2 W 15 ) is a promising CA at high magnetic fields and proves that the use of heterometallic clusters is an effective strategy to increase PRE due to the synergistic effects from different metal ions. Paramagnetism ; Chemistry ; Polyoxometalate ; Molecule ; Relaxation (psychology) ; Crystallography ; MRI contrast agent ; Nuclear magnetic resonance ; Gadolinium ; Condensed matter physics ; Catalysis ; Physics Polyoxometalates: Synthesis and Applications ; Lanthanide and Transition Metal Complexes ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Billie A Radcliffe
Source: VCU Scholars Compass (Virginia Commonwealth University) (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

A Density Functional Theory Study of Palladium Nanoparticles and Their Redox Properties on Graphene Nanoparticles exhibit characteristics that are different from bulk materials as well as from atoms resulting in their application in numerous fields of applied material science. In particular, small palladium nanoparticles supported on graphene have been found to be outstanding catalysts for the Suzuki cross-coupling reaction. One explanation as to why these supported nanoparticles are such outstanding catalysts is because they may act as both electron donors and acceptors. Charge donating ligands are known to lower the ionization energy of clusters, making the clusters better donors. In this project, it is hypothesized that graphene supports may also act like charge donating ligands, lowering the ionization energy and making the supported catalyst a better charge donor. To understand this hypothesis we investigate the structure, and energetics of small Palladium (Pd) clusters of 1-7 and 13 atoms as free clusters, and on different graphene-based supports using gradient-corrected density functional theory. Graphene is found to increases the stability of the supported clusters and we find that graphene also significantly reduces the ionization energy of the palladium clusters, which is consistent with the hypothesis that graphene is a good support for catalytic processes in part because it makes the cluster a better charge donor. Graphene ; Density functional theory ; Palladium ; Redox ; Nanoparticle ; Materials science ; Nanotechnology ; Chemistry ; Catalysis ; Computational chemistry ; Metallurgy ; Biochemistry Graphene research and applications
Authors: Abdulhakim A. Ahmed | Mohamed A El-Hag Ahmed | Raed M Abouhaddaf
Source: International Journal of Advanced Chemistry Research (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Density functional investigation of the adsorption of nitric oxide on palladium clusters (PDN n=1-6) The adsorption of nitric oxide molecule on small palladium clusters (Pdn;n=1–6) has been investigated by the density functional theory. The orientations of nitric oxide to get a nitrosyl (-NO) and Isonitrosyl (-ON) ligands were implemented. The most stable palladium clusters have been used as adsorbate. The resulting nitrosyl and Isonitrosyl palladium complexes always chemisorbs in a bent geometry. The nitrosyl complexes showed higher binding energy, charge donation, HOMO-LUMO gap and u(NO) than their isonitrosy counterparts. Looking to the thermodynamic and kinetic stability of the cluster and their interaction with nitric oxide. Palladium ; Nitric oxide ; Density functional theory ; Bent molecular geometry ; Chemistry ; Adsorption ; Oxide ; Binding energy ; Cluster (spacecraft) ; Molecule ; Kinetic energy ; Computational chemistry ; Inorganic chemistry ; Materials science ; Physical chemistry ; Catalysis ; Organic chemistry ; Atomic physics ; Physics Nanomaterials for catalytic reactions ; Inorganic Chemistry and Materials ; Nanocluster Synthesis and Applications
Authors: Lisa Sturm | Christian R. Göb | Iris M. Oppel
Source: European Journal of Inorganic Chemistry (article, 2020-12-23)
Field: Chemistry — Inorganic Chemistry

Anion Directed Selective Synthesis of Supramolecular Metallocycles and Related Coordination Dimers Abstract The reaction of C 3 ‐symmetric tris ‐(2‐pyridinylene‐ N ‐oxide)triaminoguanidinium salts ([H 3 L ]X) and zinc(II) in presence of thiocyanate and different carboxylate ions as co‐ligands yields in a series of different coordination compounds. Supramolecular metallocycles and carboxylate‐bridged dimers are defined by two fundamentally different binding motifs. By adjusting the co‐ligands’ stoichiometry, metallocycles and carboxylate‐bridged compounds can be synthesized selectively. Furthermore, the occupation of the metallocycles with co‐ligands can also be controlled that way. Directed synthesis of these metallocycles is essential for further application in host‐guest chemistry due to their cavities and porosity in the solid state. Chemistry ; Carboxylate ; Supramolecular chemistry ; Thiocyanate ; Stoichiometry ; Zinc ; Coordination complex ; Polymer chemistry ; Stereochemistry ; Molecule ; Inorganic chemistry ; Metal ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Supramolecular Chemistry and Complexes
Authors: Julie A. Peterson | Yuan Ding | Arthur H. Winter
Source: ChemRxiv (preprint, 2020-09-28)
Field: Materials Science — Materials Chemistry

Multiwavelength Control of Mixtures Using Visible Light Absorbing Photocages Selective deprotection of functional groups using different wavelengths of light is attractive for materials synthesis as well as for achieving independent photocontrol over substrates in biological systems. However, wavelength-selective activation is difficult to achieve with common UV-absorbing photoremovable protecting groups (PRPGs) because it is difficult to separate the chromophore absorption profiles. Moreover, deep UV irradiation of photocages can result in cellular phototoxicity. Here, we investigated the ability of recently-developed visible light absorbing BODIPY-derived PRPGs and a coumarin-derived PRPG to undergo wavelength selective activation in order to identify well-behaved pairs of PRPGs that allow independent optical control over a mixture of photocaged substrates using more biologically benign long-wavelength light. The three pairs of PRPGs tested have complete selectivities for cleaving the longerwavelength absorbing photocage first, and fair to excellent selectivities for releasing the lower-wavelength absorbing PRPG first when mixtures were irradiated in solution. When the PRPGs are attached to the same substrate, irradiating the shorter-wavelength absorbing PRPG results in energy transfer, but the PRPGs can be cleaved in a sequential manner starting by deprotecting the longest wavelength absorbing photocage first and then removing the lower-wavelength absorbing PRPG. A mixture of the three photocages could be sequentially reacted using common red, green, and far-UV (365 nm) LED irradiation. &lt;br&gt; Phototoxicity ; Wavelength ; Chromophore ; Visible spectrum ; Photochemistry ; Absorption (acoustics) ; Irradiation ; Chemistry ; Optoelectronics ; Substrate (aquarium) ; Materials science ; Physics Photochromic and Fluorescence Chemistry ; Click Chemistry and Applications ; Nanoplatforms for cancer theranostics
Authors: Eric C. Hosten | Richard Betz
Source: Zeitschrift für Kristallographie - New Crystal Structures (article, 2020-11-13)
Field: Chemistry — Inorganic Chemistry

The crystal structure of 3-ammonio-4-aminobenzoate, C<sub>7</sub>H<sub>8</sub>N<sub>2</sub>O<sub>2</sub> – a second polymorph Abstract C 7 H 8 N 2 O 2 , monoclinic, P 2 1 / n (no. 14), a = 8.9884(6) Å, b = 6.0490(4) Å, c = 12.1290(8) Å, β = 95.400(2)°, V = 656.54(8) Å 3 , Z = 4, R gt ( F ) = 0.0340, wR ref ( F 2 ) = 0.0978, T = 200 K. Monoclinic crystal system ; Crystallography ; Chemistry ; Crystal structure ; Stereochemistry Crystal structures of chemical compounds ; Crystallography and molecular interactions ; Chemical Synthesis and Analysis
Authors: Zoltán Nagymihály | Beáta Lemli | László Kollár | Sándor Kunsági‐Máté
Source: Molecules (article, 2020-04-21)
Field: Chemistry — Spectroscopy

Solvent Switched Weak Interaction of a 4-Quinazolinone with a Cavitand Derivative Interaction of 4-quinazolinone with tetrakis (3,5-dicarboxylatophenoxy)-cavitand derivative has been studied in methanol and dimethylformamide media using fluorescence spectroscopy and molecular modeling methods. Results show temperature dependent complex formation: either the entropy gain or the high enthalpy changes are responsible for the formation of stable complexes in two separated temperature regions. However, different thermodynamic parameters are associated to different conformations of the complexes: while the high entropy gain associated to the formation of deeply included guest in methanol, the high entropy gain is associated with the formation of weakly included guest in dimethylformamide solvent. This finding highlights the importance of dynamic properties of the species interacted in different solvents. Cavitand ; Chemistry ; Quinazolinone ; Dimethylformamide ; Solvent ; Methanol ; Derivative (finance) ; Enthalpy ; Fluorescence ; Entropy (arrow of time) ; Computational chemistry ; Molecule ; Organic chemistry ; Supramolecular chemistry ; Thermodynamics Molecular Sensors and Ion Detection ; Supramolecular Chemistry and Complexes ; Luminescence and Fluorescent Materials
Authors: Sabine Illner | Jonathan Ortelt | Daniela Arbeiter | Valeria Khaimov | Katharina Wulf | Stefan Oschatz | Thomas Reske | Volkmar Senz | K.-P. Schmitz | Niels Grabow
Source: Current Directions in Biomedical Engineering (article, 2020-09-01)
Field: Materials Science — Biomaterials

Adaptable Superfibers as Implant Material Abstract Electrospun fiber nonwoven materials of different polymer classes provide promising perspectives in almost all fields of application, including medical science. In this paper we present the fiber generation of selected biostable polymers (PBT, TPC-ET, PA 6.12 and PVDF) by direct electrospinning, as an extremely powerful tool for manufacturing of new superfiber implant materials. This initial study includes the variation of some relevant process parameters, such as polymer concentrations or electrode spacing. The influence on fiber morphology, tensile strength and biocompatibility is shown. The results presented indicate that the choice and combination of materials is crucial for the application on load-bearing implants, independent of the processing technology and thus of the fiber bonding, delamination or fiber strength. Electrospinning ; Materials science ; Biocompatibility ; Ultimate tensile strength ; Composite material ; Polymer ; Fiber ; Delamination (geology) ; Nanofiber Electrospun Nanofibers in Biomedical Applications ; Advanced Sensor and Energy Harvesting Materials ; Conducting polymers and applications
Authors: Estefanía Delgado‐Pinar | Marta Piñeiro | J. Sérgio Seixas de Melo
Source: Dalton Transactions (article, 2020-01-01)
Field: Chemistry — Spectroscopy

A water-soluble bithiophene with increased photoluminescence efficiency and metal recognition ability A new water-soluble tri-tert-butyl-bithiophenesulfonamide (α2-tbS) was synthesized and a comprehensive spectroscopic and photophysical study was undertaken in organic solvents and water at different pH values. In contrast to the behaviour found for the parent (and un-substituted) α,α'-bithiophene (α2), in which radiationless decay processes are the main excited-state deactivation channels, the tert-butylsulfonamide derivative presents a significant fluorescence quantum yield (φF) (ca. one order of magnitude higher than that of α2). The high φF allowed further exploring α2-tbS as a selective fluorimetric sensor for metal ions. A strong selectivity towards Cu(ii) is observed at neutral pH values, whereas at pH = 9.5 a strong quenching upon the addition of Hg(ii) is observed. An additional high sensitivity of 0.64 ± 0.02 ppm towards Cu(ii) was observed, well below 1.25 ppm (∼20 μM), the maximum value allowed in drinking water by the EPA. Derivatization ; Photoluminescence ; Fluorescence ; Excited state ; Selectivity ; Metal ; Water soluble ; Photochemistry ; Chemistry ; Inorganic chemistry ; Materials science ; Catalysis ; Organic chemistry ; Optoelectronics ; High-performance liquid chromatography ; Optics Molecular Sensors and Ion Detection ; Luminescence and Fluorescent Materials ; Advanced biosensing and bioanalysis techniques
Authors: Gregor T. Dahl | Jan-Dominik Krueger | Sebastian Döring | Horst Weller | Tobias Voßmeyer
Source: Nanomaterials (article, 2020-06-19)
Field: Materials Science — Materials Chemistry

Seeded Growth Synthesis of Zirconia@Gold Particles in Aqueous Solution Metal-ceramic composite particles are of increasing interest due to their potential applications in photonic metamaterials as well as next-generation catalysts. The zirconia-gold system has received little attention due to the lack of controllable preparation methods. Well-known methods for the deposition of gold nanoshells on silica spheres, however, should be adaptable for similar zirconia-based materials. Here, we present a novel synthetic approach to the well-controlled deposition of gold on the surface of sol-gel derived zirconia mesoparticles by a stepwise method involving the immobilization of gold nanoparticles and repeated seeded-growth steps. We show that the immobilization efficiency is strongly enhanced by acidification with hydrochloric acid and additional employment of aminomethylphosphonic acid as coupling agent. The optimum conditions are identified and the subsequent incremental growth by seeded reduction of gold is demonstrated. The results shed light on the parameters governing the preparation of zirconia@gold composite particles and our synthetic approach provides a promising tool for future developments in complex nanomaterials design. Materials science ; Cubic zirconia ; Nanomaterials ; Nanotechnology ; Colloidal gold ; Ceramic ; Composite number ; Chemical engineering ; Nanoparticle ; Deposition (geology) ; Composite material Catalytic Processes in Materials Science ; Advanced Photocatalysis Techniques ; Quantum Dots Synthesis And Properties
Authors: Matej Holc | Igor Karlovits | D. Ravnjak | ALEŠ PALATINUS | Junkar Ita
Source: Wood Research (article, 2020-06-30)
Field: Materials Science — General Materials Science

Influence of gaseous plasma treatment on functional properties of coated papers Three different types of paper with different coatings have been used in order to study the influence of gaseous plasma treatment on surface properties of paper. Radio frequency (RF) oxygen plasma was used for treatment of papers that contain different parts of organic and inorganic components in their coatings. Surface properties like surface morphology, roughness, surface energy, wettability, and chemistry were studied. The influence of plasma modification was also studied in terms of printability and paper gloss, which are one of the key parameters that dictate the use of such paper in desired applications. The results indicate that plasma modification of different types of coatings indeed influences paper printability as well as gloss function, which was shown to be highly connected with surface morphology, as micro-and nanopores were opened or formed due to selective plasma etching of organic part of the coating. Moreover, significant increase in surface energy was observed on all plasma treated papers, however this seemed not to influence much on the printing and gloss properties. Plasma ; Materials science ; Composite material ; Chemical engineering ; Physics ; Engineering Material Properties and Applications
Authors: Shalini Singh | Sourav Ghosh | Virender Kumar Pal | MohamedHusen Munshi | Raju S Rajmani | Govindasamy Mugesh | Amit Singh
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2020-08-15)
Field: Materials Science — Materials Chemistry

Antioxidant nanozyme counteracts HIV-1 by modulating intracellular redox potential Abstract Reactive oxygen species (ROS) regulates the proliferation of human immunodeficiency virus (HIV-1) and Mycobacterium tuberculosis ( Mtb ) inside the infected immune cells. However, the application of this knowledge to develop therapeutic strategies remained unsuccessful due to unfavorable consequences of manipulating cellular antioxidant systems that respond to ROS. Here, we show that vanadium pentoxide (V 2 O 5 ) nanosheets functionally mimic the activity of natural glutathione peroxidase (GPX) to mitigate ROS associated with HIV-1 infection without triggering detrimental changes in cellular physiology. Using genetic reporters of glutathione (GSH) redox potential ( E GSH ; Grx1-roGFP2) and H 2 O 2 (Orp1-roGFP2), we showed that V 2 O 5 -nanosheets catalyze GSH-dependent neutralization of ROS in HIV-1 infected cells. Notably, V 2 O 5 -nanosheets uniformly blocked HIV-1 reactivation, multiplication, and impaired survival of drug-resistant Mtb during HIV-TB co-infection. Mechanistically, V 2 O 5 -nanosheets suppressed HIV-1 by affecting the expression of pathways coordinating redox balance, virus transactivation ( e.g., NF-κB and FOS), inflammation, and apoptosis. Importantly, a combination of V 2 O 5 -nanosheets with a pharmacological inhibitor of NF-κB (BAY11-7082) abrogated activation of HIV-1 from latency. Lastly, V 2 O 5 -nanosheets counteracted ROS, disease pathophysiology, and virus expression in HIV-1 transgenic mice. Our data successfully revealed the usefulness of V 2 O 5 -nanosheets against human pathogens and suggest nanozymes as future platforms to develop interventions against infectious diseases. Significance Statement Redox stress, such as those caused by the deregulation of the antioxidant glutathione, promotes the multiplication of human immunodeficiency virus-1 (HIV-1) and Mycobacterium tuberculosis ( Mtb ). Here we present a vanadium pentoxide (V 2 O 5 )-based antioxidant nanozyme that targets cells infected with HIV-1. The nanozyme, by mimicking the activity of glutathione peroxidase, reprograms redox signaling to subvert HIV-1 from monocytes, lymphocytes, and HIV-1 transgenic mice. Treatment with nanozyme bolsters the antiviral potential of immune cells by reducing the expression of genes involved in virus activation, inflammation, and apoptosis. The nanozyme also inhibited the proliferation of Mtb , which is a major cause of lethality in HIV patients. These V 2 O 5 -based nanozymes may be applied to numerous human pathogens where redox signaling contributes to disease progression. Reactive oxygen species ; Transactivation ; Antioxidant ; Cell biology ; Glutathione ; Biology ; Oxidative stress ; Intracellular ; Chemistry ; Biochemistry ; Transcription factor ; Enzyme Advanced Nanomaterials in Catalysis ; Nanoparticles: synthesis and applications ; Nanocluster Synthesis and Applications