jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Daniel Fernando Hincapié-Rojas | Sandy Paola Rojas Hernández | Felipe Castaño González | Kelly Natalia Parra Castaño | Laura Rocío Giraldo Torres
Source: DYNA (article, 2020-11-18)
Field: Materials Science — Biomaterials

Obtención, funcionalización y aplicaciones biomédicas de las Nanopartículas de Sílice Mesoporosa: una revisión Recientemente, las nanopartículas inorgánicas han sido ampliamente investigadas como agentes terapéuticos en los campos biomédicos debido a sus propiedades físicas, químicas y biológicas excepcionales, su fácil funcionalización superficial, su capacidad de carga y su excelente biocompatibilidad. El creciente aumento en investigaciones centradas en nanopartículas inorgánicas en especial las de sílice ha permitido entender su comportamiento en aplicaciones biomédicas, debido a que es un biomaterial con alta resistencia mecánica, bioactividad y reabsorbilidad mejoradas. En este artículo, se realiza la revisión de estudios recientes basados en Nanopartículas de Sílice Mesoporosa (MSN) cuyo enfoque principal se centra en diferentes métodos de síntesis, funcionalización y recubrimiento de superficie y algunas aplicaciones biomédicas como liberación controlada de fármacos e imágenes diagnósticas. Finalmente, se presentan los impactos de las modificaciones químicas de la superficie de las nanopartículas en cuanto a su biocompatibilidad y las diversas aplicaciones biomédicas debido a sus destacables características. Humanities ; Physics ; Philosophy Electrospun Nanofibers in Biomedical Applications ; Bone Tissue Engineering Materials ; Nanoparticle-Based Drug Delivery
Authors: Chenliang Shi | Ling Lin | Yukun Yang | Wenjia Luo | Maoqing Deng | Yujie Wu
Source: e-Polymers (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

Synthesis of aminated polystyrene and its self-assembly with nanoparticles at oil/water interface Abstract The influence of density of amino groups, nanoparticles dimension and pH on the interaction between end-functionalized polymers and nanoparticles was extensively investigated in this study. PS–NH 2 and H 2 N–PS–NH 2 were prepared using reversible addition–fragmentation chain transfer polymerization and atom transfer radical polymerization. Zero-dimensional carbon dots with sulfonate groups, one-dimensional cellulose nanocrystals with sulfate groups and two-dimensional graphene with sulfonate groups in the aqueous phase were added into the toluene phase containing the aminated PS. The results indicate that aminated PS exhibited the strongest interfacial activity after compounding with sulfonated nanoparticles at a pH of 3. PS ended with two amino groups performed better in reducing the water/toluene interfacial tension than PS ended with only one amino group. The dimension of sulfonated nanoparticles also contributed significantly to the reduction in the water/toluene interfacial tension. The minimal interfacial tension was 4.49 mN/m after compounding PS–NH 2 with sulfonated zero-dimensional carbon dots. Polystyrene sulfonate ; Polymer chemistry ; Nanoparticle ; Toluene ; Sulfonate ; Surface tension ; Polystyrene ; Atom-transfer radical-polymerization ; Aqueous solution ; Chemistry ; Polymer ; Polymerization ; Chemical engineering ; Materials science ; Organic chemistry ; Nanotechnology Pickering emulsions and particle stabilization ; Surface Modification and Superhydrophobicity ; Advanced Cellulose Research Studies
Authors: Mostapha Dakhchoune
Source: CHIMIA International Journal for Chemistry (article, 2020-04-25)
Field: Materials Science — Materials Chemistry

Two-dimensional Material Membranes for Gas Separation Two-dimensional (2D) materials with atom- or few-atoms-thick layers have emerged as building-blocks in the synthesis of the next-generation membrane-based separations. Generally, 2D material-based membranes display high permeation and high selectivity due to their unique structure composed of nanopores and nanochannels with extremely short transport pathways. In this review, the latest advances and ground-breaking research studies on 2D nanosheets for gas separation are highlighted with a focus on the different strategies in synthesizing 2D nanosheets, their assembly into thin membranes and the type of transport mechanism taking place in such membranes. Membrane ; Permeation ; Gas separation ; Nanopore ; Materials science ; Nanotechnology ; Separation (statistics) ; Facilitated diffusion ; Chemical engineering ; Chemistry ; Engineering ; Computer science Graphene research and applications ; Membrane Separation and Gas Transport ; MXene and MAX Phase Materials
Authors: Abdellah Felouat | Julien Massue | Gilles Ulrich
Source: Dyes and Pigments (article, 2020-10-01)
Field: Chemistry — Physical and Theoretical Chemistry

Oligo(ethylene glycol) (OEG) functionalized 2-(2′-Hydroxy benzofuranyl) benzoxazole (HBBO) derivatives: Synthesis, photophysical properties and biomolecules binding studies Two molecular fluorophores based on a 2-(2′-Hydroxybenzofuranyl) benzoxazole (HBBO) scaffold and presenting an Excited-State Intramolecular Proton Transfer (ESIPT) process are reported herein. These dyes incorporate strongly electrodonating aromatic amino groups on the benzofuranyl side, enabling the appearance of a dual fluorescence emission corresponding to the radiative decay of the excited enol (E*) and keto (K*) tautomers at high and low energy respectively. It was previously demonstrated that dual E*/K* emission could originate from a beneficial decrease of phenolic acidity upon absorption of light leading to a thermodynamic stabilization of the first excited-state. The innovation within these dyes lies in the double functionalization of the aniline moiety with 2-(2-methoxyethoxy)ethyl units which allowed a better solubilization in protic solvents, as compared to their butyl analogs while keeping strong electrodonating capacity. Their intrinsic amphiphilic character leads to a good vectorization in a wide range of solvents from toluene to PBS buffer. The investigation of the photophysical properties of these dyes in solution showed a clear dual emission in apolar solvents with the E* band gradually red-shifting along with the dipole moment of the solvent. Dual emission is also observed in the solid-state when these dyes are doped as 1% wt in PMMA or PS films. Finally, the interactions of one dye with calf-thymus (ct)-DNA and Bovine Serum Albumin (BSA) have been explored and reveal pronounced modifications of the UV–Vis profile of the dye. Additionally, a gradual hypsofluorochromic shift and narrowing of the K* band along with the appearance of the E* fluorescence band upon addition of ct-DNA or BSA is also observed, presumably evidencing an intercalation mode of binding. Benzoxazole ; Chemistry ; Photochemistry ; Excited state ; Ethylene glycol ; Intramolecular force ; Carbazole ; Anthracene ; Absorption (acoustics) ; Fluorescence ; Solvatochromism ; Solvent ; Organic chemistry ; Materials science Photochemistry and Electron Transfer Studies ; Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research
Authors: Vilmos Kertész | John F. Cahill | Bernadeta Srijanto | C. Patrick Collier | Marissa Vavrek | Bingming Chen
Source: Rapid Communications in Mass Spectrometry (article, 2020-11-25)
Field: Chemistry — Spectroscopy

Absolute quantitation of propranolol from 200‐μm regions of mouse brain and liver thin tissues using laser ablation‐dropletProbe‐mass spectrometry This work illustrates that depositing a thin layer of parylene C onto thin tissue prior to analysis, which seals the surface and prevents direct liquid extraction of the drug from the tissue, coupled to the novel LA-dropletProbe surface sampling system is a viable approach for sub-mm resolution quantitative drug distribution analysis. Chromatography ; Parylene ; Mass spectrometry ; Ablation ; Analytical Chemistry (journal) ; Laser ablation ; Resolution (logic) ; Chemistry ; Materials science ; Propranolol ; Biomedical engineering ; Laser ; Optics Mass Spectrometry Techniques and Applications ; Analytical chemistry methods development ; Analytical Chemistry and Chromatography
Authors: Laura Juhász | Bence Parditka | P. Petrík | Csaba Cserháti | Zoltán Erdélyi
Source: Journal of Porous Materials (article, 2020-07-11)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Continuous tuning of the plasmon resonance frequency of porous gold nanoparticles by mixed oxide layers Abstract Porous gold nanoparticles (PGNs) are very popular due to their high surface/volume ratio, moreover they have stronger plasmonic properties than their solid counterparts. These properties make the porous gold nanoparticles very useful for lots of applications, for instance chemical sensors, cancer therapy applications. For applications, however, it is indispensable that the resonance frequency (RF) of a plasmonic structure to be tuneable. In this work we show that the RF can be set in a wide range as desired by coating the PGNs by mixed oxide layers. By changing the composition of the coating layer, that is the mixture ratio, the RF can be shifted practically continuously in a wide range determined by the refractive index of the used oxides. As a demonstration, PGNs were coated with mixed alumina-titania oxide layers (5–7 nm) using plasma-enhanced atomic layer deposition method. The oxide layer, beside as a tuning tool, also stabilises the structure of the PGNs when are exposed to elevated temperature. This is shown by the influence of the temperature (from $$350\, ^{\circ }\hbox {C}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>350</mml:mn> <mml:msup> <mml:mspace /> <mml:mo>∘</mml:mo> </mml:msup> <mml:mtext>C</mml:mtext> </mml:mrow> </mml:math> up to $$900\, ^{\circ }\hbox {C}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>900</mml:mn> <mml:msup> <mml:mspace /> <mml:mo>∘</mml:mo> </mml:msup> <mml:mtext>C</mml:mtext> </mml:mrow> </mml:math> ) on the morphology, and as a consequence the optical extinction spectra, of the oxide coated PGNs. Materials science ; Oxide ; Nanoparticle ; Surface plasmon resonance ; Layer (electronics) ; Analytical Chemistry (journal) ; Nanotechnology ; Chemistry ; Chromatography Gold and Silver Nanoparticles Synthesis and Applications ; Nanoporous metals and alloys ; Copper-based nanomaterials and applications
Authors: Adam T. Szafran | Michael J. Bolt | Caroline E. Obkirchner | Maureen G. Mancini | Christine Helsen | Frank Claessens | Fabio Stossi | Michael A. Mancini
Source: SLAS DISCOVERY (article, 2020-05-11)
Field: Chemistry — Spectroscopy

A Mechanistic High-Content Analysis Assay Using a Chimeric Androgen Receptor That Rapidly Characterizes Androgenic Chemicals Androgen receptor ; High-content screening ; Androgen ; Chemistry ; Cell biology ; Pharmacology ; Computational biology ; Internal medicine ; Biology ; Medicine ; Biochemistry ; Cell ; Hormone Mass Spectrometry Techniques and Applications ; Effects and risks of endocrine disrupting chemicals ; Analytical Chemistry and Chromatography
Authors: David Liese | Hans Henning Wenk | Xin Lü | Jochen Kleinen | Gebhard Haberhauer
Source: Beilstein Journal of Organic Chemistry (article, 2020-11-19)
Field: Chemistry — Organic Chemistry

Dirhamnolipid ester – formation of reverse wormlike micelles in a binary (primerless) system We report new dirhamnolipid ester forming reverse wormlike micelles in nonpolar solvents without the addition of any primer. Therefore, these compounds represent a rare case of a binary system showing this gel-like behavior. In this study, the influence of the concentration of the rhamnolipid ester and the ester alkyl chain length on the rheological properties of the reverse wormlike micelles in toluene was investigated in detail. Highly viscoelastic solutions were obtained even at a relatively low concentration of less than 1 wt %. The phase transition temperatures indicate that the formation of reverse wormlike micelles is favored for dirhamnolipid esters with shorter alkyl chain lengths. Oscillatory shear measurements for the viscoelastic samples reveal that the storage modulus (<i>G'</i>) and the loss modulus (<i>G''</i>) cross each other and fit the Maxwell model very well in the low-ω region. As is typical for wormlike micelle systems, the normalized Cole-Cole plot of <i>G''</i>/<i>G''</i> <sub>max</sub> against <i>G'</i>/<i>G''</i> <sub>max</sub> was obtained as a semicircle centered at <i>G'</i>/<i>G''</i> <sub>max</sub> = 1. The formation of network structures was also verified by polarized light microscopy. The sample was birefringent at ambient temperature and anisotropic at an elevated temperature. Differential scanning calorimetry analysis yielded a transition enthalpy of about Δ<i>H</i> <sub>SG/GS</sub> = ±7.2 kJ/mol. This value corresponds to a strong dispersion energy and explains the formation of the highly viscous gels by the entanglement of wormlike micelles through the interaction of the alkyl chains. Micelle ; Chemistry ; Alkyl ; Viscoelasticity ; Dynamic mechanical analysis ; Differential scanning calorimetry ; Dynamic modulus ; Glass transition ; Enthalpy ; Polymer chemistry ; Thermodynamics ; Polymer ; Organic chemistry ; Aqueous solution Surfactants and Colloidal Systems ; Lipid Membrane Structure and Behavior ; Enhanced Oil Recovery Techniques
Authors: Manon Demulder | Lieven De Veylder | Remy Loris
Source: Acta Crystallographica Section F Structural Biology Communications (article, 2020-04-01)
Field: Materials Science — Materials Chemistry

Crystal structure of <i>Arabidopsis thaliana</i> casein kinase 2 α1 Casein kinase 2 (CK2) is a ubiquitous pleiotropic enzyme that is highly conserved across eukaryotic kingdoms. CK2 is singular amongst kinases as it is highly rigid and constitutively active. Arabidopsis thaliana is widely used as a model system in molecular plant research; the biological functions of A. thaliana CK2 are well studied in vivo and many of its substrates have been identified. Here, crystal structures of the α subunit of A. thaliana CK2 in three crystal forms and of its complex with the nonhydrolyzable ATP analog AMppNHp are presented. While the C-lobe of the enzyme is highly rigid, structural plasticity is observed for the N-lobe. Small but significant displacements within the active cleft are necessary in order to avoid steric clashes with the AMppNHp molecule. Binding of AMppNHp is influenced by a rigid-body motion of the N-lobe that was not previously recognized in maize CK2. Arabidopsis thaliana ; Casein kinase 2 ; Protein subunit ; Casein kinase 1 ; Enzyme ; Kinase ; Biology ; Chemistry ; Biochemistry ; Transferase ; Steric effects ; Stereochemistry ; Cell biology ; Biophysics ; Protein kinase A ; Gene ; Mitogen-activated protein kinase kinase Enzyme Structure and Function ; Phytase and its Applications ; Plant biochemistry and biosynthesis
Authors: Salha Hamri | Jabrane Jouha | Asmaa Oumessaoud | María Dolors Pujol | Mostafà Khouili | Gérald Guillaumet
Source: Tetrahedron (article, 2020-11-16)
Field: Chemistry — Organic Chemistry

Convenient approach for the synthesis of ONO-LB-457, a potent leukotriene B4 receptor antagonist Chemistry ; Wittig reaction ; Knoevenagel condensation ; Malonic acid ; Intramolecular force ; Stereochemistry ; Yield (engineering) ; Hydrolysis ; Olefin fiber ; Medicinal chemistry ; Organic chemistry ; Catalysis Chemical Synthesis and Reactions ; Inflammatory mediators and NSAID effects ; Synthetic Organic Chemistry Methods
Authors: S.Z. Kiss | Neil MacKinnon | Jan G. Korvink
Source: Research Square (preprint, 2020-12-11)
Field: Chemistry — Spectroscopy

Microfluidic Overhauser DNP Chip for Signal-enhanced Compact NMR Abstract Nuclear magnetic resonance at low field strength is an insensitive spectroscopic technique, precluding portable applications with small sample volumes, such as needed for biomarker detection in body fluids. Here we report a compact double resonant chip stack system that implements in situ dynamic nuclear polarisation of a 130 nL sample volume, achieving a signal enhancement of 54 w.r.t. the thermal equilibrium level at a microwave power level of 0.5W. This work overcomes instrumental barriers to the use of NMR detection for point-of-care applications. Stack (abstract data type) ; Microfluidics ; SIGNAL (programming language) ; Chip ; Materials science ; Microwave ; Nuclear magnetic resonance ; Power (physics) ; Microwave power ; Sample (material) ; Optoelectronics ; Analytical Chemistry (journal) ; Nanotechnology ; Chemistry ; Physics ; Computer science ; Telecommunications ; Chromatography Advanced NMR Techniques and Applications ; Electron Spin Resonance Studies ; Microwave and Dielectric Measurement Techniques
Authors: Yvonne Abel | Ivan Vlassiouk | Enno Lork | Sergei Smirnov | Marat R. Talipov | Franz‐Peter Montforts
Source: Chemistry - A European Journal (article, 2020-07-06)
Field: Materials Science — Materials Chemistry

Symmetry Effects in Photoinduced Electron Transfer in Chlorin‐Quinone Dyads: Adiabatic Suppression in the Marcus Inverted Region In donor-acceptor dyads undergoing photoinduced electron transfer (PET), a direction or pathway for electron movement is usually dictated by the redox properties and the separation distance between the donor and acceptor subunits, while the effect of symmetry is less recognized. We have designed and synthesized two isomeric donor-acceptor assemblies in which electronic coupling between donor and acceptor is altered by the orbital symmetry control with the reorganization energy and charge transfer exothermicity being kept unchanged. Analysis of the optical absorption and luminescence spectra, supported by the DFT and TD-DFT calculations, showed that PET in these assemblies corresponds to the Marcus inverted region (MIR) and has larger rate for isomer with weaker electronic coupling. This surprising observation provides the first experimental evidence for theoretically predicted adiabatic suppression of PET in MIR, which unambiguously controlled solely by symmetry. Acceptor ; Adiabatic process ; Electron transfer ; Chemistry ; Photoinduced electron transfer ; Photochemistry ; Coupling (piping) ; Marcus theory ; Electron acceptor ; Symmetry (geometry) ; Molecular physics ; Atomic physics ; Materials science ; Physics ; Condensed matter physics ; Reaction rate constant ; Kinetics Porphyrin and Phthalocyanine Chemistry ; Photochemistry and Electron Transfer Studies ; Photosynthetic Processes and Mechanisms
Authors: Lena Reinke | Julia Bartl | Marcus Koch | Stefan Kubik
Source: Beilstein Journal of Organic Chemistry (article, 2020-11-02)
Field: Chemistry — Spectroscopy

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes Gold nanoparticles covered with a mixture of ligands of which one type contains solubilizing triethylene glycol residues and the other peripheral zinc(II)-dipicolylamine (DPA) complexes allowed the optical detection of hydrogenphosphate, diphosphate, and triphosphate anions in water/methanol 1:2 (v/v). These anions caused the bright red solutions of the nanoparticles to change their color because of nanoparticle aggregation followed by precipitation, whereas halides or oxoanions such as sulfate, nitrate, or carbonate produced no effect. The sensitivity of phosphate sensing depended on the nature of the anion, with diphosphate and triphosphate inducing visual changes at significantly lower concentrations than hydrogenphosphate. In addition, the sensing sensitivity was also affected by the ratio of the ligands on the nanoparticle surface, decreasing as the number of immobilized zinc(II)-dipicolylamine groups increased. A nanoparticle containing a 9:1 ratio of the solubilizing and the anion-binding ligand showed a color change at diphosphate and triphosphate concentrations as low as 10 μmol/L, for example, and precipitated at slightly higher concentrations. Hydrogenphosphate induced a nanoparticle precipitation only at a concentration of ca. 400 μmol/L, at which the precipitates formed in the presence of diphosphates and triphosphates redissolved. A nanoparticle containing fewer binding sites was more sensitive, while increasing the relative number of zinc(II)-dipicolylamine complexes beyond 25% had a negative impact on the limit of detection and the optical response. Transmission electron microscopy provided evidence that the changes of the nanoparticle properties observed in the presence of the phosphates were due to a nanoparticle crosslinking, consistent with the preferred binding mode of zinc(II)-dipicolylamine complexes with phosphate anions which involves binding of the anion between two metal centers. This work thus provided information on how the behavior of mixed monolayer-protected gold nanoparticles is affected by multivalent interactions, at the same time introducing a method to assess whether certain biologically relevant anions are present in an aqueous solution within a specific concentration range. Chemistry ; Nanoparticle ; Inorganic chemistry ; Zinc ; Colloidal gold ; Nuclear chemistry ; Organic chemistry ; Nanotechnology Molecular Sensors and Ion Detection ; Electrochemical sensors and biosensors ; Electrochemical Analysis and Applications
Authors: Dulal Pal
Source: Journal of Scientific Research (article, 2020-05-01)
Field: Materials Science — Materials Chemistry

Conventional and Inverse Magnetocaloric Effect in Ni-Rich Ni-Mn-Ga and Ni-Mn-Sn Heusler Alloy: A Comparison Magnetic and magnetocaloric effect of Ni-rich Ni52Mn34Sn14 (Ni-Mn-Sn) and Ni54Mn17Ga29 (Ni-Mn-Ga) Heusler alloys have been investigated up to a magnetic field of 5T and within a temperature range of 4.2 – 325 K. In this study, we report a systematic comparison between Ni-rich Ni52Mn34Sn14 and Ni54Mn17Ga29 alloys in the light of their magnetocaloric effect (MCE). In both the samples, a large magnetic entropy change was observed (~96 J kg-1 K-1 for Ni-Mn-Ga), but for the alloy Ni-Mn-Sn the MCE becomes negative/inverse. From various magnetic measurements it have been observed that in Ni-Mn-Sn alloy the martensite to austenite transition accompanied by lower to higher magnetization whereas for Ni-Mn-Ga alloy reverse situation occurred. The different type of magnetocaloric effect, i.e. inverse and direct can be explained by considering magneto-crystalline anisotropy and different state of magnetization of the martensite and austenite phase of the alloys. Magnetic refrigeration ; Materials science ; Austenite ; Alloy ; Magnetization ; Magnetic shape-memory alloy ; Martensite ; Condensed matter physics ; Metallurgy ; Inverse ; Atmospheric temperature range ; Magnetic field ; Magnetic anisotropy ; Microstructure ; Thermodynamics ; Physics Shape Memory Alloy Transformations ; Magnetic Properties and Applications ; Aeroelasticity and Vibration Control