scholarly journals Recent Advances of Hierarchical and Sequential Growth of Macromolecular Organic Structures on Surface

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 662 ◽  
Author(s):  
Corentin Pigot ◽  
Frédéric Dumur
Keyword(s):  
Supramolecular Chemistry ◽  
Data Storage ◽  
Materials Science ◽  
Growth Control ◽  
Linear Polymers ◽  
Research Activity ◽  
Covalent Bonds ◽  
New Approach ◽  
Promising Strategy ◽  
Important Milestone

The fabrication of macromolecular organic structures on surfaces is one major concern in materials science. Nanoribbons, linear polymers, and porous nanostructures have gained a lot of interest due to their possible applications ranging from nanotemplates, catalysis, optoelectronics, sensors, or data storage. During decades, supramolecular chemistry has constituted an unavoidable approach for the design of well-organized structures on surfaces displaying a long-range order. Following these initial works, an important milestone has been established with the formation of covalent bonds between molecules. Resulting from this unprecedented approach, various nanostructures of improved thermal and chemical stability compared to those obtained by supramolecular chemistry and displaying unique and unprecedented properties have been developed. However, a major challenge exists: the growth control is very delicate and a thorough understanding of the complex mechanisms governing the on-surface chemistry is still needed. Recently, a new approach consisting in elaborating macromolecular structures by combining consecutive steps has been identified as a promising strategy to elaborate organic structures on surface. By designing precursors with a preprogrammed sequence of reactivity, a hierarchical or a sequential growth of 1D and 2D structures can be realized. In this review, the different reaction combinations used for the design of 1D and 2D structures are reported. To date, eight different sequences of reactions have been examined since 2008, evidencing the intense research activity existing in this field.

Solid Lipid Nanoparticles: A Promising Drug Delivery Technology

2009 ◽  
Vol 2 (2) ◽  
pp. 509-516
Author(s):  
S. Pragati ◽  
S. Kuldeep ◽  
S. Ashok ◽  
M. Satheesh
Keyword(s):  
Drug Delivery ◽  
Solid Lipid Nanoparticles ◽  
Large Scale ◽  
Colloidal Particles ◽  
Scale Up ◽  
Lipid Nanoparticles ◽  
Scale Production ◽  
Research Activity ◽  
New Approach ◽  
Solid Lipid

One of the situations in the treatment of disease is the delivery of efficacious medication of appropriate concentration to the site of action in a controlled and continual manner. Nanoparticle represents an important particulate carrier system, developed accordingly. Nanoparticles are solid colloidal particles ranging in size from 1 to 1000 nm and composed of macromolecular material. Nanoparticles could be polymeric or lipidic (SLNs). Industry estimates suggest that approximately 40% of lipophilic drug candidates fail due to solubility and formulation stability issues, prompting significant research activity in advanced lipophile delivery technologies. Solid lipid nanoparticle technology represents a promising new approach to lipophile drug delivery. Solid lipid nanoparticles (SLNs) are important advancement in this area. The bioacceptable and biodegradable nature of SLNs makes them less toxic as compared to polymeric nanoparticles. Supplemented with small size which prolongs the circulation time in blood, feasible scale up for large scale production and absence of burst effect makes them interesting candidates for study. In this present review this new approach is discussed in terms of their preparation, advantages, characterization and special features.

scholarly journals Strain-stabilized superconductivity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. P. Ruf ◽  
H. Paik ◽  
N. J. Schreiber ◽  
H. P. Nair ◽  
L. Miao ◽  
...  
Keyword(s):  
Thin Films ◽  
Materials Science ◽  
Condensed Matter ◽  
Quantum States ◽  
Low Energy ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Detailed Understanding ◽  
Epitaxial Strain ◽  
Promising Strategy

AbstractSuperconductivity is among the most fascinating and well-studied quantum states of matter. Despite over 100 years of research, a detailed understanding of how features of the normal-state electronic structure determine superconducting properties has remained elusive. For instance, the ability to deterministically enhance the superconducting transition temperature by design, rather than by serendipity, has been a long sought-after goal in condensed matter physics and materials science, but achieving this objective may require new tools, techniques and approaches. Here, we report the transmutation of a normal metal into a superconductor through the application of epitaxial strain. We demonstrate that synthesizing RuO2 thin films on (110)-oriented TiO2 substrates enhances the density of states near the Fermi level, which stabilizes superconductivity under strain, and suggests that a promising strategy to create new transition-metal superconductors is to apply judiciously chosen anisotropic strains that redistribute carriers within the low-energy manifold of d orbitals.

Novel Inorganic Hydrogels Based on The Polymerization of Cyanometalate Transition Metal Complexes With [PdCl4]2-: A New Approach To Ceramic And Alloy Precursors

1994 ◽  
Vol 346 ◽  
Author(s):  
Andrew B. Bocarsly ◽  
Gireesh Kumar ◽  
Marija Heibel
Keyword(s):  
Transition Metal ◽  
Metal Ion ◽  
Sol Gel ◽  
Metallic Matrix ◽  
Linear Polymers ◽  
New Approach ◽  
Square Planar ◽  
Delafossite Structure ◽  
Cyanide Ligand ◽  
Sol Gel Transition

ABSTRACTThe reaction of a wide variety of cyanometalate complexes of the general form [M(CN)x]n- (where M= a transition metal ion) with square planar [PdCl4]2- in aqueous solution leads to the formation of linear polymers. Polymerization occurs via substitution of chloride ligands on the Pd(II) centers, by the nitrogen end of the cyanide ligand to generate extended bridging cyanide structures. Upon generation at room temperature polymer solutions of this type under go a sol-gel transition to generate robust hydrogels having water content in excess of 95%. In the case of the cyanocobaltate/tetrachloropalladate gel, pyrolysis at 900°C produces ferromagnetic Pd/Co metallic alloys having novel morphological character. Materials formed with a hydrogel having a 2:1 Pd to Co stoichiometry are found to be “sponge-like”. When placed in water, the metallic matrix swells becoming pliable and holding up to seven equivalents of water per metal site. The conductivity and magnetic properties of this material are maintained in the swollen state. Sintering of the Pd/Co hydrogel in air generates the layered oxide, PbCoO2 having a delafossite structure.

Comparing mathematical and heuristic approaches for scientific data analysis

2007 ◽  
Vol 22 (1) ◽  
pp. 53-69 ◽  
Author(s):  
Aparna S. Varde ◽  
Shuhui Ma ◽  
Mohammed Maniruzzaman ◽  
David C. Brown ◽  
Elke A. Rundensteiner ◽  
...  
Keyword(s):  
Mathematical Models ◽  
Data Storage ◽  
Materials Science ◽  
Scientific Data ◽  
Estimation Problem ◽  
Predictive Analysis ◽  
Heuristic Methods ◽  
Science Data ◽  
Domain Specific ◽  
Computational Estimation

AbstractScientific data is often analyzed in the context of domain-specific problems, for example, failure diagnostics, predictive analysis, and computational estimation. These problems can be solved using approaches such as mathematical models or heuristic methods. In this paper we compare a heuristic approach based on mining stored data with a mathematical approach based on applying state-of-the-art formulae to solve an estimation problem. The goal is to estimate results of scientific experiments given their input conditions. We present a comparative study based on sample space, time complexity, and data storage with respect to a real application in materials science. Performance evaluation with real materials science data is also presented, taking into account accuracy and efficiency. We find that both approaches have their pros and cons in computational estimation. Similar arguments can be applied to other scientific problems such as failure diagnostics and predictive analysis. In the estimation problem in this paper, heuristic methods outperform mathematical models.

Can hydrological model identifiability be improved? Stress-testing the concept of stochastic calibration

2021 ◽  
Author(s):  
Vasileios Kourakos ◽  
Andreas Efstratiadis ◽  
Ioannis Tsoukalas
Keyword(s):  
Dependence Structure ◽  
Hydrological Models ◽  
Proof Of Concept ◽  
Rainfall Runoff ◽  
Predictive Capacity ◽  
New Approach ◽  
Stochastic Inputs ◽  
Promising Strategy ◽  
Synthetic Time Series ◽  
Temporal Windows

<p>Hydrological calibrations with historical data are often deemed insufficient for deducing safe estimations about a model structure that imitates, as closely as possible, the anticipated catchment behaviour. Ιn order to address this issue, we investigate a promising strategy, using as drivers synthetic time series, which preserve the probabilistic properties and dependence structure of the observed data. The key idea is calibrating a model on the basis of synthetic rainfall-runoff data, and validating against the full observed data sample. To this aim, we employed a proof of concept on few representative catchments, by testing several lumped conceptual hydrological models with alternative parameterizations and across two time-scales, monthly and daily. Next, we attempted to reinforce the validity of the recommended methodology by employing monthly stochastic calibrations in 100 MOPEX catchments. As before, a number of different hydrological models were used, for the purpose of proving that calibration with stochastic inputs is independent of the chosen model. The results highlight that in most cases the new approach leads to stronger parameter identifiability and stable predictive capacity across different temporal windows, since the model is trained over much extended hydroclimatic conditions.</p>

scholarly journals A New Approach to Producing High Yields of Pulcherrimin from Metschnikowia Yeasts

Fermentation ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 114
Author(s):  
Ewelina Pawlikowska ◽  
Beata Kolesińska ◽  
Maria Nowacka ◽  
Dorota Kregiel
Keyword(s):  
Culture Media ◽  
Growth Control ◽  
Tween 80 ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Biofilm Inhibition ◽  
Iron Chelate ◽  
New Approach ◽  
1H Nuclear Magnetic Resonance ◽  
High Yields

Pulcherrimin, a red iron chelate, is produced by some yeasts and bacteria. It plays important ecological roles in many ecosystems, including growth control, biofilm inhibition and photoprotection. In this study, fifteen yeast strains of the genus Metschnikowia were characterized based on their production of pulcherrimin. Yeast pulcherrimin was isolated and its purity assessed using 1H nuclear magnetic resonance spectroscopy. Under experimental conditions, pulcherrimin formation varied depending on both the tested strains and culture media. The best producers formed up to 240 mg/L of pulcherrimin in minimal medium with glucose as the carbon source, supplemented with 0.05% FeCl3 and 0.1% Tween 80. This study presents a new approach to producing high yields of pulcherrimin from yeasts.

Recent aspects of self-oscillating polymeric materials: designing self-oscillating polymers coupled with supramolecular chemistry and ionic liquid science

2014 ◽  
Vol 16 (22) ◽  
pp. 10388-10397 ◽  
Author(s):  
Takeshi Ueki ◽  
Ryo Yoshida
Keyword(s):  
Ionic Liquid ◽  
Supramolecular Chemistry ◽  
Polymeric Materials ◽  
Building Blocks ◽  
Covalent Bonds ◽  
Spatiotemporal Structure ◽  
Molecular Building Blocks ◽  
Recent Developments

Herein, we summarise the recent developments in self-oscillating polymeric materials based on the concepts of supramolecular chemistry, where aggregates of molecular building blocks with non-covalent bonds evolve the temporal or spatiotemporal structure.

scholarly journals Surface functionalization of dinuclear clathrochelates via Pd-catalyzed cross-coupling reactions: facile synthesis of polypyridyl metalloligands

2016 ◽  
Vol 45 (20) ◽  
pp. 8422-8427 ◽  
Author(s):  
Mathieu Marmier ◽  
Giacomo Cecot ◽  
Basile F. E. Curchod ◽  
Philip Pattison ◽  
Euro Solari ◽  
...  
Keyword(s):  
Supramolecular Chemistry ◽  
Surface Functionalization ◽  
Materials Science ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Facile Synthesis ◽  
Cross Coupling Reactions

Clathrochelates can be decorated with pyridyl groups by cross-coupling reactions. They represent interesting ligands for supramolecular chemistry and materials science.

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