Binding of calcium cations with three different types of oxygen-based functional groups of superplasticizers studied by atomistic simulations

2018 ◽  
Vol 24 (11) ◽  
Author(s):  
Hongxia Zhao ◽  
Yong Yang ◽  
Yanwei Wang ◽  
Xin Shu ◽  
Shishan Wu ◽  
...  
Keyword(s):  
Functional Groups ◽  
Atomistic Simulations ◽  
Calcium Cations ◽  
Different Types

New approaches to the design of analgesic medicinal substances

2021 ◽  
Author(s):  
Ilya V. Rogachevskii ◽  
Vera B. Plakhova ◽  
Valentina A. Penniyaynen ◽  
Stanislav G. Terekhin ◽  
Svetlana A. Podzorova ◽  
...  
Keyword(s):  
Functional Groups ◽  
Receptor Binding ◽  
Therapeutic Potential ◽  
Medicinal Substance ◽  
Neuron Membrane ◽  
Comenic Acid ◽  
Structural Criterion ◽  
Calcium Cations ◽  
Medicinal Substances ◽  
Living Neurons

A gamma-pyrone derivative, comenic acid, activates the opioid-like receptor-mediated signaling pathway that modulates the NaV1.8 channels in the primary sensory neuron membrane. These channels are responsible for generation of the nociceptive signal; gamma-pyrones can therefore have a great therapeutic potential as analgesics, and this effect deserves a deeper understanding. The novelty of our approach to the design of a medicinal substance is based on a combination of the data obtained on living neurons using very sensitive physiological methods and the results of quantum-chemical calculations. This approach allows to correlate the molecular structure of gamma-pyrones with their ability to evoke a physiological response of the neuron. Comenic acid can bind two calcium cations. One of them is chelated by the carbonyl and the hydroxyl functional groups, while another one forms the salt bond with the carboxylate anion. Calcium-bound gamma-pyrones are fundamentally different in electrostatic properties from the free gamma-pyrone molecules. These two calcium ions are the key elements involved in ligand-receptor binding. It is very likely ion-ionic interactions between these cations and anionic functional groups of the opioid-like receptor that activate the latter. The calculated intercationic distance of 9.5 Å is a structural criterion for effective ligand-receptor binding of calcium-bound gamma-pyrones.

scholarly journals Understanding medical civil-military relationships within the humanitarian-development-peace ‘triple nexus’: a typology to enable effective discourse

2020 ◽  
pp. jramc-2019-001382 ◽  
Author(s):  
Simon Horne ◽  
S Boland
Keyword(s):  
Functional Groups ◽  
Future Study ◽  
Relative Stability ◽  
Visual Representation ◽  
Geographical Area ◽  
Common Language ◽  
Different Types ◽  
Foreign Policies ◽  
Military Activity ◽  
Hearts And Minds

The interface between humanitarianism, development and peacebuilding is increasingly congested. Western foreign policies have shifted towards pro-active stabilisation agendae and so Civil-Military Relationships (CMRel) will inevitably be more frequent. Debate is hampered by lack of a common language or clear, mutually understood operational contexts to define such relationships. Often it may be easier to simply assume that military co-operation attempts are solely to ‘win hearts and minds’, rather than attempt to navigate the morass of different acronyms. In healthcare, such relationships are common and more complex - partly as health is seen as both an easy entry point for diplomacy and so is a priority for militaries, and because health is so critical to apolitical humanitarian responses. This paper identifies the characteristics of commonly described kinds of CMRel, and then derives a typology that describe them in functional groups as they apply to healthcare-related contexts (although it is likely to be far more widely applicable). Three broad classifications are described, and then mapped against 6 axes; the underlying military and civilian motivations, the level of the engagement (strategic to tactical), the relative stability of the geographical area, and finally the alignment between the civilian and military interests. A visual representation shows where different types may co-exist, and where they are likely to be more problematic. The model predicts two key areas where friction is likely; tactical interactions in highly unstable areas and in lower threat areas where independent military activity may undermine ongoing civilian programmes. The former is well described, supporting the typology. The latter is not and represents an ideal area for future study. In short, we describe an in-depth typology mapping the Civil-Military space in humanitarian and development contexts with a focus on healthcare, defining operational spaces and the identifying of areas of synergy and friction.

Effects of aphids and moth caterpillars on epiphytic microorganisms in canopies of forest trees

2000 ◽  
Vol 30 (4) ◽  
pp. 631-638 ◽  
Author(s):  
Bernhard Stadler ◽  
Thomas Müller
Keyword(s):  
Population Dynamics ◽  
Functional Groups ◽  
Filamentous Fungi ◽  
Growing Season ◽  
Aphid Species ◽  
Growth Media ◽  
Forest Trees ◽  
Epiphytic Microorganisms ◽  
Colony Forming Units ◽  
Different Types

Different types of herbivores were investigated for their effects on microorganisms in the phyllosphere of forest trees during the growing season. Aphids on spruce, beech, and oak produced honeydew, which was readily consumed by microorganisms and resulted in two to three orders of magnitude higher densities (colony forming units) of bacteria, yeasts, and filamentous fungi on leaves of infested trees. The amounts of honeydew excreted by different aphid species and their mode of excretion (large droplets, tiny droplets scattered over leaves, production of wax wool) affected the degree to which honeydew could be processed by epiphytic microorganisms. All groups of microorganisms appeared to be energy limited. These results were consistent for different growth media offered to the microorganisms. Leaf-feeding moth caterpillars also positively affected the growth of microorganisms on leaves of beech and oak. The effects were more pronounced for bacteria and yeasts especially on oak. Thus, different functional groups of herbivores positively affected the growth of microorganisms in the phyllosphere of trees. It is suggested that the population dynamics of herbivores and their feeding characteristics are important features, which should be considered when the population dynamics of microorganisms in the canopies of trees is studied.

scholarly journals Columnar Aggregates of Azobenzene Stars: Exploring Intermolecular Interactions, Structure, and Stability in Atomistic Simulations

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7598
Author(s):  
Markus Koch ◽  
Marina Saphiannikova ◽  
Olga Guskova
Keyword(s):  
Hydrogen Bonds ◽  
Md Simulations ◽  
Binding Energies ◽  
Atomistic Simulations ◽  
Π Interactions ◽  
Different Types ◽  
Non Covalent Interactions ◽  
Experimental Works ◽  
Supramolecular Aggregates ◽  
Covalent Interactions

We present a simulation study of supramolecular aggregates formed by three-arm azobenzene (Azo) stars with a benzene-1,3,5-tricarboxamide (BTA) core in water. Previous experimental works by other research groups demonstrate that such Azo stars assemble into needle-like structures with light-responsive properties. Disregarding the response to light, we intend to characterize the equilibrium state of this system on the molecular scale. In particular, we aim to develop a thorough understanding of the binding mechanism between the molecules and analyze the structural properties of columnar stacks of Azo stars. Our study employs fully atomistic molecular dynamics (MD) simulations to model pre-assembled aggregates with various sizes and arrangements in water. In our detailed approach, we decompose the binding energies of the aggregates into the contributions due to the different types of non-covalent interactions and the contributions of the functional groups in the Azo stars. Initially, we investigate the origin and strength of the non-covalent interactions within a stacked dimer. Based on these findings, three arrangements of longer columnar stacks are prepared and equilibrated. We confirm that the binding energies of the stacks are mainly composed of π–π interactions between the conjugated parts of the molecules and hydrogen bonds formed between the stacked BTA cores. Our study quantifies the strength of these interactions and shows that the π–π interactions, especially between the Azo moieties, dominate the binding energies. We clarify that hydrogen bonds, which are predominant in BTA stacks, have only secondary energetic contributions in stacks of Azo stars but remain necessary stabilizers. Both types of interactions, π–π stacking and H-bonds, are required to maintain the columnar arrangement of the aggregates.

Synthesis, electrochromic, halochromic and electro-optical properties of polyazomethines with a carbazole core and triarylamine units serving as functional groups

2015 ◽  
Vol 3 (14) ◽  
pp. 3482-3493 ◽  
Author(s):  
Xiaochuan Ma ◽  
Haijun Niu ◽  
Hailin Wen ◽  
Shuhong Wang ◽  
Yongfu Lian ◽  
...  
Keyword(s):  
Optical Properties ◽  
Functional Groups ◽  
Direct Polycondensation ◽  
Different Types

A series of aromatic polyazomethines (PAMs) were prepared via direct polycondensation from 9-(2-ethylhexyl)-carbazole-3,6-dicarboxaldehyde and six different types of diamine containing triarylamines.

Target-specificity of feral pig baits under different conditions in a tropical rainforest

2011 ◽  
Vol 38 (5) ◽  
pp. 370 ◽  
Author(s):  
Andrew J. Bengsen ◽  
Luke K.-P. Leung ◽  
Steven J. Lapidge ◽  
Iain J. Gordon
Keyword(s):  
Seasonal Variation ◽  
Functional Groups ◽  
Tropical Rainforests ◽  
Target Species ◽  
Novel Foods ◽  
Different Types ◽  
Poison Baiting ◽  
Consumption Rates ◽  
Presentation Methods ◽  
Feral Pig

Context The mitigation of feral pig (Sus scrofa) impacts in north Queensland’s World Heritage tropical rainforests is constrained by the lack of an effective and target-specific poison baiting method. Aims This study aimed to determine whether easily implemented bait presentation methods or seasonal variation in bait acceptability could be used to selectively reduce the consumption of feral pig baits by non-target species. Methods We exposed manufactured feral pig baits to pigs and non-target species in the field, and compared bait encounter, sampling and consumption rates for different functional groups of species among three different types of bait presentation and composition. We then exposed baits under different seasonal conditions and related bait encounter and consumption by different functional groups to seasonally variable phenomena. Key results Shallow burial greatly reduced bait consumption by most non-target species, but not dingoes (Canis lupus dingo). Nocturnal bait distribution and seasonal baiting were less useful. Pigs showed substantial seasonal variation in physiological condition, suggesting that pigs should be more susceptible to consuming novel foods, such as baits, after periods of low rainfall. However, few pigs consumed the manufactured baits used in this study. Conclusions Manufactured baits are not currently suitable for widespread use in the region. However, shallow burial should provide an effective method of reducing non-target bait-take if baits can be made more attractive and acceptable to pigs and less acceptable to dingoes. Implications Future efforts to enable effective feral pig control in the region should focus on developing baiting materials that are more attractive to pigs and unappealing to dingoes.

scholarly journals A sandcastle worm-inspired strategy to functionalize wet hydrogels

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Donghui Zhang ◽  
Jingjing Liu ◽  
Qi Chen ◽  
Weinan Jiang ◽  
Yibing Wang ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Functional Groups ◽  
Wound Repair ◽  
Functional Polymers ◽  
Polymer Chains ◽  
Biological Functions ◽  
Reactive Site ◽  
Direct Modification ◽  
Different Types ◽  
One Step

AbstractHydrogels have been extensively used in many fields. Current synthesis of functional hydrogels requires incorporation of functional molecules either before or during gelation via the pre-organized reactive site along the polymer chains within hydrogels, which is tedious for polymer synthesis and not flexible for different types of hydrogels. Inspired by sandcastle worm, we develop a simple one-step strategy to functionalize wet hydrogels using molecules bearing an adhesive dibutylamine-DOPA-lysine-DOPA tripeptide. This tripeptide can be easily modified with various functional groups to initiate diverse types of polymerizations and provide functional polymers with a terminal adhesive tripeptide. Such functional molecules enable direct modification of wet hydrogels to acquire biological functions such as antimicrobial, cell adhesion and wound repair. The strategy has a tunable functionalization degree and a stable attachment of functional molecules, which provides a tool for direct and convenient modification of wet hydrogels to provide them with diverse functions and applications.

scholarly journals Are Rate and Selectivity Correlated in Iridium-Catalysed Hydrogen Isotope Exchange Reactions?

2021 ◽  
Author(s):  
Daria Timofeeva ◽  
David Lindsay ◽  
William Kerr ◽  
David Nelson
Keyword(s):  
Functional Groups ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Lewis Base ◽  
Exchange Reactions ◽  
Different Types ◽  
Observed Behaviour ◽  
Directing Group ◽  
The Relationship

Herein we examine the relationship between reaction rate and reaction selectivity in iridium-catalysed hydrogen isotope<br>exchange (HIE) reactions directed by Lewis basic functional groups. We have recently develped a directing group scale that allows semi-quantitative predictions of Lewis base directed selectivity in HIE, formally ranking ‘relative rates’ determined from a structured set of competition experiments. Here, we show that selectivity and rate are in fact not correlated, but that different types of behaviour emerge in competition experiments and that the observed behaviour can be predicted from our established selectivity scale.

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