jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Müjgan Okur
Source: Journal of Polytechnic (article, 2020-05-29)
Field: Materials Science — Biomaterials

Borik Asit, Sitrik Asit, Askorbik Asit İçeren Polikaprolakton/Halloysit Filmlerin Ambalaj Malzemesi Olarak Değerlendirilmesi Biyopolimerlerin ambalaj malzemesi olarak kullanımı düşük mekanik, termal ve bariyer özelliklere sahip olması nedeniyle kısıtlıdır. Bu kısıtlama biyopolimerlere dolgu malzemeleri eklenerek giderilebilmektedir. Bu çalışmada saf polikaprolakton (PCL) ve % 0,5 w/v oranında halloysit (HAL) karıştırılarak, PCL/HAL filmler çözelti döküm yöntemiyle hazırlanmıştır. Bu filmlere yapısal (ATR-FTIR ve XRD), termal (TGA) ve mekanik (çekme-kopma, sertlik) testler yapılmıştır. PCL/HAL filmlerin Terime sıcaklığı, sertlik ve gerilme dayanımlarında saf PCL filmlere göre artış gözlenmiştir. PCL filmlerin antimikrobiyal etkisini incelemek için PCL/HAL filmlere borik asit, sitrik asit ve askorbik asit (% 0,25) eklenmiştir. Bu filmlerin antimikrobiyal etkisi gram pozitif Staphylococcus aureus 29213 ve gram negatif Escheria coli 35218 bakterilerine karşı incelenmiştir. Antimikrobiyal aktivite deneyi sonucunda filmlere eklenen borik asit, sitrik asit ve askorbik asit miktarının yeterli inhibisyon etkisi gösteremediği gözlenmiştir. Sonuç olarak saf PCL’ye HAL eklenmesi filmlerin mekanik özelliklerinde artışa sebep olmuştur ve bu nedenle ambalaj malzemesi olarak kullanılabilir potansiyele sahip olduğu düşünülmektedir. Nuclear chemistry ; Boric acid ; Citric acid ; Chemistry ; Materials science ; Food science ; Organic chemistry biodegradable polymer synthesis and properties ; Nanocomposite Films for Food Packaging ; Electrospun Nanofibers in Biomedical Applications
Authors: Aleš Stýskalík | Imène Kordoghli | Claude Poleunis | Arnaud Delcorte | Denis Dochain | Z. Moravec | Julius A. Vida | Tomáš Homola | Carmela Aprile | Luca Fusaro | François Devred | Damien P. Debecker
Source: ChemRxiv (preprint, 2020-12-17)
Field: Materials Science — Materials Chemistry

Non-Hydrolytic Sol-Gel Route to a Family of Hybrid Mesoporous Aluminosilicate Ethanol Dehydration Catalysts Organic-inorganic hybrid materials are nowadays intensely studied for potential applications in heterogeneous catalysis because their properties and catalytic behavior differ from pristine inorganic counterparts. The organic groups at the catalyst surface can modify not only its hydrophilicity, but also acidity, hydrothermal stability, porosity, etc. In some cases, such properties alteration leads to improved catalytic performance in terms of activity, selectivity, or stability. However, the choice of organic groups stays relatively narrow, as most reports focus on pendant methyl groups. Here, a series of mesoporous hybrid aluminosilicate materials containing various organic groups was prepared in one pot by non-hydrolytic sol-gel (NHSG). Both aromatic and aliphatic, pendant and bridging organic groups were incorporated. The presence of the organic groups in the bulk and at the outermost surface of the materials was verified by solid-state NMR and ToF-SIMS, respectively. Aluminum is mostly incorporated in tetrahedral coordination in the hybrid silica matrix. The organically modified mesoporous aluminosilicate samples were tested as catalysts in the gas phase ethanol dehydration (which relies on solid acids) and most of them outperformed the purely inorganic catalyst benchmark. While a direct influence of surface hydrophilicity or hydrophobicity (as probed by water sorption and water contact angle measurements) appeared unlikely, characterization of acidity (IR-pyridine) revealed that the improved performance for hybrid catalysts can be correlated with a modification of the acidic properties. In turn, acidity is determined by the quality of the dispersion of Al centers in the form of isolated sites in the hybrid silica matrix. All in all, this study establishes a "ranking" for a variety of organic groups in terms of their effect on gas-phase ethanol dehydration to ethylene; ethylene yield decreases in this order: bridging xylylene ≈ pendant methyl &gt; pendant benzyl &gt; bridging methylene ≈ inorganic benchmark (no organic groups) &gt; bridging ethylene.&lt;br&gt; Aluminosilicate ; Catalysis ; Mesoporous material ; Hybrid material ; Hydrolysis ; Sorption ; Chemistry ; Chemical engineering ; Inorganic chemistry ; Materials science ; Organic chemistry ; Adsorption Mesoporous Materials and Catalysis ; Zeolite Catalysis and Synthesis ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Wenzhao Fu | Qianhong Wang | Wenyao Chen | Gang Qian | Jing Zhang | De Chen | Wei Yuan | Xinggui Zhou | Xuezhi Duan
Source:  (preprint, 2020-09-02)
Field: Materials Science — Materials Chemistry

Fabrication and engineering of Ru local structures toward enhanced kinetics of hydrogen generation A strategy to boost hydrogen generation from ammonia borane hydrolysis was proposed by engineering Ru local structures via the employment of Cl-free Ru precursors and acid-leaching of the bimetallic Ru-Co catalysts. The effects of Cl and Co were separately investigated by comparing the Cl-free/Cl-containing monometallic Ru catalysts and Co-leaching/Co-containing bimetallic Ru-Co catalysts, respectively. Decoupled from the Co electronic effects (electron transfer from Co to Ru), the Cl geometric effects (site blockage and steric hindrance) were identified as the main factors, which could be further promoted by introducing more low-coordinated Ru sites. The increase of Co content gives rise to more edge-like Ru active sites after acid leaching, with a lower H2O activation barrier for hydrogen production. Consequently, al-Ru1Co with the most edge-like Ru active sites demonstrated a 4.1-fold increase in catalytic activity. The insights revealed here might guide the design and preparation of metal catalysts with the maximum active sites. Bimetallic strip ; Ammonia borane ; Catalysis ; Leaching (pedology) ; Chemistry ; Steric effects ; Ruthenium ; Hydrogen production ; Hydrogen ; Inorganic chemistry ; Stereochemistry ; Organic chemistry Hydrogen Storage and Materials ; Ammonia Synthesis and Nitrogen Reduction ; Electrocatalysts for Energy Conversion
Authors: Mauro Perfetti | Andréa Caneschi | Taisiya S. Sukhikh | Kira E. Vostrikova
Source: ChemRxiv (preprint, 2020-08-14)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Lanthanide Complexes with a Tripodal Nitroxyl Radical Showing Strong Magnetic Coupling A series of isomorphous mononuclear complexes of Ln(III) ions comprising one stable tripoidal oxazolidine nitroxyl radical were obtained in acetonitrile media starting from nitrates. The compounds, [LnRad(NO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;3&lt;/sub&gt;] (Ln = Gd, Tb, Dy, Tm, Y; Rad = 4,4-dimethyl-2,2-bis(pyridin-2-yl)-1,3-oxazolidine-3-oxyl), have molecular structure. Their coordination polyhedron, LnO&lt;sub&gt;7&lt;/sub&gt;N&lt;sub&gt;2&lt;/sub&gt;, can be described as a tricapped trigonal prism with symmetry close to &lt;i&gt;D&lt;/i&gt;&lt;sub&gt;3h&lt;/sub&gt;. The value of 23 cm&lt;sup&gt;-1&lt;/sup&gt; for the antiferromagnetic coupling Gd-Rad established from the &lt;i&gt;DC&lt;/i&gt; magnetic and EPR data is a record strength for the complexes of 4f-elements with nitroxyl radicals. The terbium derivative displays frequency-dependent out-of-phase signals in zero field indicating single-molecule magnetic behavior with an effective barrier of 57 cm&lt;sup&gt;-1&lt;/sup&gt;. Chemistry ; Crystallography ; Electron paramagnetic resonance ; Molecule ; Coordination sphere ; Radical ; Antiferromagnetism ; Stereochemistry ; Nuclear magnetic resonance ; Crystal structure ; Physics Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Electron Spin Resonance Studies
Authors: Julie Peterson | Ding Yuan | 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. Phototoxicity ; Wavelength ; Chromophore ; Photochemistry ; Visible spectrum ; Absorption (acoustics) ; Irradiation ; Chemistry ; Optoelectronics ; Materials science ; Physics Photochromic and Fluorescence Chemistry ; Polydiacetylene-based materials and applications ; Nanoplatforms for cancer theranostics
Authors: Nicholas K. Pinkin | Bei Liu | Frederico M. Pimenta | Klaus M. Hahn
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2020-07-16)
Field: Chemistry — Organic Chemistry

Using SNAP-tag for facile construction of dye-based biosensors in living cells Abstract Fluorescent biosensors based on environment-sensitive dyes have important advantages over alternative methodologies such as FRET, including the potential for enhanced brightness, elimination of bleaching artifacts, and more possibilities for multiplexing. However, such biosensors have been difficult to use because they required proteins to be covalently labeled and reintroduced into cells. Recent development of self-labeling enzymes that covalently react with membrane-permeable dyes (e.g. SNAP-tag) provide an opportunity to easily generate dye-based biosensors within cells. Here, we generate a new biosensor for Cdc42 activation by positioning SNAP-tag between Cdc42 and a peptide that binds selectively to active Cdc42. We generate a membrane-permeable Nile Red derivative that exhibits 50-fold fluorescence enhancement upon covalent labeling of the biosensor, then optimize the biosensor so the dye undergoes a 20 nm emission shift upon Cdc42 activation, enabling ratiometric imaging with a single dye. The biosensor, named SNAPsense Cdc42, is validated by examining its response to known regulatory proteins and studying Cdc42 activation during protrusion in living cells. Variants using other dyes are also presented. Biosensor ; Förster resonance energy transfer ; Fluorescence ; Covalent bond ; Chemistry ; CDC42 ; Biophysics ; Nanotechnology ; Biochemistry ; Materials science ; Biology ; Cell Click Chemistry and Applications ; Advanced Fluorescence Microscopy Techniques ; Advanced biosensing and bioanalysis techniques
Authors: Nadica D. Abazović | Tatjana D. Savić | Tatjana Novaković | Mirjana I. Čomor | Zorica Mojović
Source: Journal of the Serbian Chemical Society (article, 2020-12-02)
Field: Chemistry — Electrochemistry

Electrochemical oxidation of 2,4,6-trichlorophenol on iron-doped nanozirconia ceramic Solvothermaly synthesized zirconium oxide nanopowders, pure and doped with various amounts of iron ions (1?20 %), were used as modifiers of glassy carbon electrodes. The modified electrodes were tested in the reaction of electrochemical oxidation of 2,4,6-trichlorophenol (TCP) in order to investigate the influence of doping on electrochemical performance of zirconia matrix. The techniques of cyclic voltammetry and electrochemical impedance spectroscopy were employed. Cyclic voltammetry showed that electrooxidation of TCP proceeded through the oxidation of hydroxyl group. Possible pathway included the formation of quinones and the formation of polyphenol film on the electrode surface, leading to the electrode fouling. Iron doping enhanced the activity of zirconia matrix towards TCP electrooxidation. Electrochemical impedance spectroscopy showed the importance of iron content in zirconia matrix for the preferable pathway of TCP electrooxidation. The quinone formation pathway was favoured by low iron doped zirconia (doped with 1% of iron), while polyphenol film formation on the electrode surface was more pronounced at samples with higher iron ion content (for doping with 10 and 20 % of iron). The sample with 5 % of added iron ions, showed intermediate behaviour, where the formed polyphenol film showed slight degradation. Dielectric spectroscopy ; Cyclic voltammetry ; Electrochemistry ; Inorganic chemistry ; Cubic zirconia ; Electrode ; Materials science ; Zirconium ; Chemistry ; Ceramic ; Metallurgy Electrochemical Analysis and Applications ; Conducting polymers and applications ; Electrochemical sensors and biosensors
Authors: Jieun Kim | Eduardo Lupi | David Pesquera | Megha Acharya | Wenbo Zhao | Gabriel Velarde | Sinéad M. Griffin | Lane W. Martin
Source: MRS Advances (article, 2020-09-08)
Field: Materials Science — Materials Chemistry

Beyond Expectation: Advanced Materials Design, Synthesis, and Processing to Enable Novel Ferroelectric Properties and Applications Materials science ; Nanotechnology ; Ferroelectricity ; Perspective (graphical) ; Material Design ; Engineering physics ; Field (mathematics) ; Materials processing ; Function (biology) ; Systems engineering ; Computer science ; Process engineering ; Engineering ; Optoelectronics ; Artificial intelligence Ferroelectric and Piezoelectric Materials ; Multiferroics and related materials ; Ferroelectric and Negative Capacitance Devices
Authors: Elizabeth H. Pempe | Jian Liu | Yongmei Xu
Source: UNC Libraries (article, 2020-11-09)
Field: Chemistry — Organic Chemistry

Chemoenzymatic Synthesis of Heparin Oligosaccharides with both Anti-factor Xa and Anti-factor IIa Activities Heparan sulfate (HS) and heparin are highly sulfated polysaccharides. Heparin is a commonly used anticoagulant drug that inhibits the activities of factors Xa and IIa (also known as thrombin) to prevent blood clot formation. Here, we report the synthesis of a series of size-defined oligosaccharides to probe the minimum size requirement for an oligosaccharide with anti-IIa activity. The synthesis was completed by a chemoenzymatic approach involving glycosyltransferases, HS sulfotransferases, and C5-epimerase. We demonstrate the ability to synthesize highly purified N-sulfo-oligosaccharides having up to 21 saccharide residues. The results from anti-Xa and anti-IIa activity measurements revealed that an oligosaccharide longer than 19 saccharide residues is necessary to display anti-IIa activity. The oligosaccharides also exhibit low binding toward platelet factor 4, raising the possibility of preparing a synthetic heparin with a reduced effect of heparin-induced thrombocytopenia. The results from this study demonstrate the ability to synthesize large HS oligosaccharides and provide a unique tool to probe the structure and function relationships of HS that require the use of large HS fragments. Factor (programming language) ; Heparin ; Chemistry ; Pharmacology ; Stereochemistry ; Biochemistry ; Biology ; Computer science Carbohydrate Chemistry and Synthesis
Authors: Deepak Sridhar
Source: eScholarship@McGill (McGill) (article, 2020-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Carbon-nanofiber electrodes directly grown on a nickel foam current collector for electrochemical energy storage devices Supercapacitors are gaining interest in the energy storage sector and are working their way to replace batteries or to provide a high-power supplement to the battery energy.Despite their high-power density and long cycle life, their energy density is low presently.Even with the use of high surface area materials like graphene, activated carbon, and metal oxides, there has not been a considerable increase in the energy density, mostly due to the electrode preparation methods.This thesis has focused on preparing carbon nano fibers (CNF) that are directly grown on nickel foam current collectors, resulting in electrodes that are not only mechanically stable but also have an extended micro-porous structure on the macro-porous nickel foam.This leads to a electrochemical active surface area ca.400 m 2 /g and thus provides a good architecture for enhanced performance of surface-limited electrochemical reactions.The electrode Electrode ; Nickel ; Current (fluid) ; Materials science ; Energy storage ; Current collector ; Carbon nanofiber ; Electrochemistry ; Nanotechnology ; Carbon nanotube ; Chemistry ; Metallurgy ; Electrical engineering ; Electrolyte ; Engineering Supercapacitor Materials and Fabrication ; Advancements in Battery Materials ; Conducting polymers and applications
Authors: Sam Benson | Fabio De Moliner | A. Garrido Fernández | Erkin Kuru | Nicholas Asiimwe | Jun‐Seok Lee | Lloyd Hamilton | Dirk Sieger | Isabel Bravo | Abigail Elliot | Yi Feng | Marc Vendrell
Source: ChemRxiv (preprint, 2020-11-12)
Field: Chemistry — Organic Chemistry

Photoactivatable Metabolic Warheads Enable Precise and Safe Ablation of Target Cells in Vivo Photoactivatable molecules enable ablation of malignant cells under the control of light, yet current agents can be ineffective at early stages of disease when target cells are similar to healthy surrounding tissues. In this work, we describe a chemical platform based on amino-substituted benzoselenadiazoles to build photosensitizers that mimic native metabolites as indicators of disease onset and progression. Through a series of synthetic derivatives, we have identified the key chemical groups in the benzoselenadiazole scaffold responsible for its photodynamic activity, and subsequently designed photosensitive metabolic warheads to target cells associated with various diseases, including bacterial infections and cancer. We demonstrate that versatile benzoselenadiazole metabolites can selectively kill pathogenic cells -but not healthy cells- with high precision after exposure to non-toxic visible light, reducing any potential side effects in vivo. This chemical platform provides powerful new tools to exploit cellular metabolic signatures for safer therapeutic and surgical approaches. &lt;br&gt; In vivo ; Chemistry ; Cancer research ; Computational biology ; Biology ; Biotechnology Click Chemistry and Applications ; Radical Photochemical Reactions ; Nanoplatforms for cancer theranostics
Authors: Seyed M. Allameh | Morteza Sadat-Hossieny | Paul Cooper
Source:  (article, 2020-09-03)
Field: Materials Science — Biomaterials

Instrumentation Of Rv M1 Robots For Developing Biologically Inspired Materials The extensive devastation caused by hurricanes Katrina and Rita in southern US has intensified efforts to build structures that are resistant to shear forces of nature, typical of hurricanes, tsunamis and earthquakes. With the superior properties of biologically inspired materials such as nacre, which combine high strength with toughness, it is desirable to mimic nature in construction of large and small structures. Due to the fine details of the layered microstructure of nacre, it is almost impossible to mimic it with the conventional fabrication methods. The nano/micro-scale thickness of the hard and soft layers that comprise the hard shell of nacre requires innovative automated in-situ fabrication processes that span various fields including materials science, robotics, construction and metrology. This paper describes the details of instrumentation for robotic construction using RV-M1 robots. It also presents some preliminary results on the fabrication of biomimicked materials. For the robotic part, vision enabled robots were equipped with dispensers to build bio-mimicked layered composites. Labview virtual instruments (VIs) were developed to guide the robots, to actuate injectors, and to analyze images. The implications of this work for the projects assigned at the undergraduate level as well as students' capstone project will also be discussed. Instrumentation (computer programming) ; Robot ; Computer science ; Robotics ; Fabrication ; Artificial intelligence ; Systems engineering ; Engineering ; Nanotechnology ; Mechanical engineering ; Materials science Calcium Carbonate Crystallization and Inhibition ; Innovations in Concrete and Construction Materials ; Soft Robotics and Applications
Authors: Rebecca Grünbauer | Michael Seidl | Gábor Balázs | Manfred Scheer
Source: Zeitschrift für anorganische und allgemeine Chemie (article, 2020-12-03)
Field: Chemistry — Organic Chemistry

Utilizing the weak P−Cr bond in [{Cp*Cr(CO)<sub>3</sub>}<sub>2</sub>(μ,η<sup>1:1</sup>−P<sub>4</sub>)] for the generation of different P<sub>4</sub> butterfly compounds Abstract A novel reactivity of [{Cp*Cr(CO) 3 } 2 (μ,η 1:1 −P 4 )] (Cp*=C 5 Me 5 ; 1 ) is reported, which utilizes the selective cleavage of the two P−Cr bonds and subsequently initiates a substituent exchange yielding P 4 butterfly compounds. By means of NMR and IR spectroscopy studies, the successful implementation of 1 to obtain [{Cp′′′Fe(CO) 2 } 2 (μ,η 1:1 −P 4 )] (Cp′′′=C 5 H 2 t Bu 3 ; 2 ) and Cp′′′ 2 P 4 ( 3 ) could be confirmed, by reacting 1 with 2.0 eq. of K[Cp′′′Fe(CO) 2 ] or NaCp′′′, respectively. Hereby, a quantitative conversion could be detected alongside the formation of 2.0 eq. of the [Cp*Cr(CO) 3 ] − anion. Moreover, various syntheses of novel organometallic and organo‐P 4 butterfly compounds were examined and first results show that the generation of different compounds should be possible. However, the isolation and stabilization of these sensitive molecules proves to be a major challenge. Chemistry ; Substituent ; Molecule ; Reactivity (psychology) ; Group 2 organometallic chemistry ; Bond cleavage ; Crystallography ; Nuclear magnetic resonance spectroscopy ; Stereochemistry ; Medicinal chemistry ; Catalysis ; Organic chemistry Organometallic Complex Synthesis and Catalysis ; Synthesis and characterization of novel inorganic/organometallic compounds ; Coordination Chemistry and Organometallics
Authors: Emilia Balcer | Maciej Mazur
Source: Prospects in Pharmaceutical Sciences (article, 2020-08-07)
Field: Materials Science — Materials Chemistry

NANOCZĄSTKI ZŁOTA W DIAGNOSTYCE I TERAPII NOWOTWORÓW – WYBRANE ZASTOSOWANIA Nanomedycyna jest obecnie jedną z najszybciej rozwijających się dziedzin nanotechnologii, znajdującą coraz więcej zastosowań w walce z chorobami nowotworowymi. Nanocząstki złota, ze względu na swoje unikalne właściwości optyczne i chemiczne, cieszą się rosnącym zainteresowaniem naukowców. Do zalet nanocząstek złota należą między innymi wysoki stosunek powierzchni do objętości cząstki, duże możliwości modyfikacji ich powierzchni, czy też występowanie efektu wzmocnionej przepuszczalności i retencji, pozwalającego na bardziej efektywną i selektywną akumulację leku w miejscach zmienionych nowotworowo. W pracy krótko omówiono charakterystykę fizykochemiczną nanocząstek złota oraz przedstawiono ich wybrane zastosowania zarówno w diagnostyce, jak i terapii chorób nowotworowych. Physics Nanoparticles: synthesis and applications ; Nanoparticle-Based Drug Delivery ; Graphene and Nanomaterials Applications