scholarly journals The Stoichiometry, Structure and Possible Formation of Crystalline Diastereomeric Salts

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 667
Author(s):  
Dorottya Fruzsina Bánhegyi ◽  
Emese Pálovics
Keyword(s):  
Melting Point ◽  
Phase Diagrams ◽  
Dynamic Equilibrium ◽  
Decisive Role ◽  
The Self ◽  
Racemic Compound ◽  
Self Organized ◽  
Supramolecular Associations ◽  
Diastereomeric Salts ◽  
The Given

Knowing the eutectic composition of the binary melting point phase diagrams of the diastereomeric salts formed during the given resolution, the achievable F (F = eeDia*Y) value can be calculated. The same value can also be calculated and predicted by knowing the eutectic compositions of the binary melting point phase diagrams of enantiomeric mixtures of the racemic compound or the resolving agent. An explanation was sought as to why and how the crystalline precipitated diastereomeric salt—formed in the solution between a racemic compound and the corresponding resolving agent—may be formed. According to our idea, the self-disproportionation of enantiomers (SDE) has a decisive role when the enantiomers form two nonequal ratios of conformers in solution. The self-organized enantiomers form supramolecular associations having M and P helicity, and double helices are formed. Between these double spirals, with the formation of new double spirals, a dynamic equilibrium is achieved and the salt crystallizes. During this process between acids and bases, chelate structures may also be formed. Acids appear to have a crucial impact on these structures. It is assumed that the behavior of each chiral molecule is determined by its own code. This code validates the combined effect of constituent atoms, bonds, spatial structure, charge distribution, flexibility and complementarity.

Adhesive Joining Process and Joint Property With Low Melting Point Filler

2005 ◽  
Vol 127 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Kiyokazu Yasuda ◽  
Jong-Min Kim ◽  
Kozo Fujimoto
Keyword(s):  
Melting Point ◽  
Volume Fraction ◽  
The Self ◽  
Matched Pair ◽  
Conduction Path ◽  
Scanning Calorimetry ◽  
Self Organized ◽  
Joint Morphology ◽  
Joining Process ◽  
Joint Property

In order to conquer the limitation of conventional solders and adhesives used in electronics packaging, a novel self-organized joining process using conductive adhesive with low melting point alloy was proposed. As a basic characteristic of the adhesive paste, the differential scanning calorimetry analysis was carried out. Joint morphology, the formation of conduction path, and the self-organized characteristics were examined. Melting fillers were preserved their initial spherelike form for nonreductive adhesive, although enlargement of the alloy colony occurred in the case of the reductive polymer. The formation of a conduction path can be controlled significantly by varying the resin performance and the process parameters such as the joint height and the volume fraction of filler. The self-organized characteristic was observed on the copper line patterned glass-epoxy substrate. The matched pair of substrates could be interconnected with excellent self-organized joint.

Formation of Giant SiGe Crystals on Insulator by Self-Organized-Seeding Rapid-Melting Growth

2013 ◽  
Vol 481 ◽  
pp. 27-29
Author(s):  
Ryo Matsumura ◽  
Hironori Chikita ◽  
T. Sadoh ◽  
M. Miyao
Keyword(s):  
Melting Point ◽  
Grain Boundaries ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
The Self ◽  
Solidification Point ◽  
Lateral Growth ◽  
Rapid Melting ◽  
Self Organized ◽  
Crystal Seed

Rapid-melting growth of SiGe stripes on insulator without crystal-seed has been investigated. After rapid-thermal annealing (RTA) of amorphous SiGe stripes (~5 μm) at a temperature between melting-point and solidification-point, SiGe crystals with large lateral sizes (~20 μm) are formed. The Si concentrations in the grains show peaks at the center of the grains and gradually decrease toward the grain boundaries. These phenomena are explained based on the self-organized formation of Si-rich micro-crystals and subsequent Si-segregating lateral-growth during RTA.

Problem behavior in autism spectrum disorders: A paradigmatic self-organized perspective of network structures

2019 ◽  
Vol 42 ◽  
Author(s):  
Lucio Tonello ◽  
Luca Giacobbi ◽  
Alberto Pettenon ◽  
Alessandro Scuotto ◽  
Massimo Cocchi ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Problem Behaviors ◽  
Autism Spectrum ◽  
The Self ◽  
Network Structures ◽  
Self Organized ◽  
Critical Equilibrium ◽  
Self Organized Criticality ◽  
Acute Agitation ◽  
Spectrum Disorders

AbstractAutism spectrum disorder (ASD) subjects can present temporary behaviors of acute agitation and aggressiveness, named problem behaviors. They have been shown to be consistent with the self-organized criticality (SOC), a model wherein occasionally occurring “catastrophic events” are necessary in order to maintain a self-organized “critical equilibrium.” The SOC can represent the psychopathology network structures and additionally suggests that they can be considered as self-organized systems.

scholarly journals Tripeptide Self-Assembly into Bioactive Hydrogels: Effects of Terminus Modification on Biocatalysis

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 173
Author(s):  
Marina Kurbasic ◽  
Ana M. Garcia ◽  
Simone Viada ◽  
Silvia Marchesan
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Chemical Modifications ◽  
Ability To Work ◽  
Active Compounds ◽  
Future Design ◽  
Self Organized ◽  
The Future ◽  
Bio Material ◽  
Supramolecular Catalysts

Bioactive hydrogels based on the self-assembly of tripeptides have attracted great interest in recent years. In particular, the search is active for sequences that are able to mimic enzymes when they are self-organized in a nanostructured hydrogel, so as to provide a smart catalytic (bio)material whose activity can be switched on/off with assembly/disassembly. Within the diverse enzymes that have been targeted for mimicry, hydrolases find wide application in biomaterials, ranging from their use to convert prodrugs into active compounds to their ability to work in reverse and catalyze a plethora of reactions. We recently reported the minimalistic l-His–d-Phe–d-Phe for its ability to self-organize into thermoreversible and biocatalytic hydrogels for esterase mimicry. In this work, we analyze the effects of terminus modifications that mimic the inclusion of the tripeptide in a longer sequence. Therefore, three analogues, i.e., N-acetylated, C-amidated, or both, were synthesized, purified, characterized by several techniques, and probed for self-assembly, hydrogelation, and esterase-like biocatalysis. This work provides useful insights into how chemical modifications at the termini affect self-assembly into biocatalytic hydrogels, and these data may become useful for the future design of supramolecular catalysts for enhanced performance.

scholarly journals Investigation of single-domain Au silicide nanowires on Si(110) formed for Au coverages in the monolayer regime

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephan Appelfeller
Keyword(s):  
Fermi Level ◽  
Surface Structure ◽  
Density Of States ◽  
The Self ◽  
Single Domain ◽  
Photoemission Spectroscopy ◽  
Annealing Temperatures ◽  
Self Organized ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy

AbstractThe self-organized formation of single domain Au silicide nanowires is observed on Si(110). These nanowires are analysed using scanning tunnelling microscopy (STM) and spectroscopy (STS) as well as photoemission spectroscopy (PES). Core-level PES is utilised to confirm the formation of Au silicide and establish its presence as the top most surface structure, i.e., the nanowires. The growth of the Au silicide nanowires and their dimensions are studied by STM. They form for Au coverages of about 1 monolayer and are characterized by widths of about 2 to 3 nm and heights below 1 nm while reaching lengths exceeding 500 nm when choosing appropriate annealing temperatures. Valence band PES and STS indicate a small but finite density of states at the Fermi level typical for compound metals.

scholarly journals Ion Beam Nanopatterning of Biomaterial Surfaces

2021 ◽  
Vol 11 (14) ◽  
pp. 6575
Author(s):  
Yu Yang ◽  
Adrian Keller
Keyword(s):  
Material Properties ◽  
Ion Beam ◽  
The Self ◽  
Solid Surfaces ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Future Directions ◽  
Self Organized ◽  
Functional Surfaces ◽  
Biomaterial Surfaces

Ion beam irradiation of solid surfaces may result in the self-organized formation of well-defined topographic nanopatterns. Depending on the irradiation conditions and the material properties, isotropic or anisotropic patterns of differently shaped features may be obtained. Most intriguingly, the periodicities of these patterns can be adjusted in the range between less than twenty and several hundred nanometers, which covers the dimensions of many cellular and extracellular features. However, even though ion beam nanopatterning has been studied for several decades and is nowadays widely employed in the fabrication of functional surfaces, it has found its way into the biomaterials field only recently. This review provides a brief overview of the basics of ion beam nanopatterning, emphasizes aspects of particular relevance for biomaterials applications, and summarizes a number of recent studies that investigated the effects of such nanopatterned surfaces on the adsorption of biomolecules and the response of adhering cells. Finally, promising future directions and potential translational challenges are identified.

Fluctuations at the self-organized critical state

1997 ◽  
Vol 56 (6) ◽  
pp. 6710-6718 ◽  
Author(s):  
Hans-Henrik Stølum
Keyword(s):  
Critical State ◽  
The Self ◽  
Self Organized

Studies of Compositional Variations in Germanium Quantum Dots Grown on Silicon

2000 ◽  
Vol 638 ◽  
Author(s):  
Alan D.F. Dunbar ◽  
Matthew P. Halsall ◽  
Uschi Bangert ◽  
Alan Harvey ◽  
Philip Dawson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
The Self ◽  
Asymmetric Distribution ◽  
Scanning Transmission Electron ◽  
Self Organized ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Uk

AbstractWe report optical and scanning transmission electron microscopy studies of germanium dots grown on silicon. In an attempt to control the self-organized growth process and promote dot size uniformity the dot layers were grown on a 4.5nm Si0.6Ge0.4 alloy template layer. Photoluminescence results indicate the formation of carrier confining Ge rich islands, whilst Raman scattering results indicate the presence of an alloy throughout the structures formed. The samples were studied in the UK high resolution scanning transmission electron microscopy facility at Liverpool, UK. Energy dispersive analysis of individual line scans through the sample show that the structures are composed of an alloy throughout with an asymmetric distribution of Germanium in the dots and in the wetting layer close to the dots. We discuss the results in the light of the proposed growth mode for these dots and conclude that attempts to manipulate the composition of these dots during growth may be problematic due to the self-organized nature of their formation.

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