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Hydrogen-Bond Acceptor Properties of Nitro-O Atoms : A Combined Crystallographic Database and Ab Initio Molecular Orbital Study
Crystallographic data for 620 C - nitro-O⋯H - N,O hydrogen bonds, involving 560 unique H atoms, have been investigated to the van der Waals limit of 2.62 Å. The overall mean nitro-O⋯H bond length is 2.30 (1) Å, which is much longer (weaker) than comparable hydrogen bonds involving >C=O acceptors in ketones, carboxylic acids and amides. The donor hydrogen prefers to approach the nitro-O atoms in th
Retardation of Aβ42 fibril formation by apolipoprotein A-I and recombinant HDL particles
The double nucleation mechanism of amyloid β (Aβ) peptide aggregation is retained from buffer to cerebrospinal fluid (CSF) but with reduced rate of all microscopic processes. Here, we used a bottom-up approach to identify retarding factors in CSF. We investigated the Aβ42 fibril formation as a function of time in the absence and presence of apolipoprotein A-I (ApoA-I), recombinant high-density lip
Solubility of foreign molecules in stratum corneum brick and mortar structure
The barrier function of the skin is mainly assured by its outermost layer, stratum corneum (SC). One key aspect in predicting dermal drug delivery and in safety assessment of skin exposure to chemicals is the need to determine the amount of chemical that is taken up into the SC. We here present a strategy that allows for direct measures of the amount of various solid chemicals that can be dissolve
Ganglioside GM3 stimulates lipid-protein co-assembly in α-synuclein amyloid formation
Parkinson's disease is characterized by the aggregation of the presynaptic protein α-synuclein (αSyn), and its co-assembly with lipids and other cellular matter in the brain. Here we investigated lipid-protein co-assembly in a system composed of αSyn and model membranes containing the glycolipid ganglioside GM3. We quantified the uptake of lipids into the co-assembled aggregates and investigated h
Hydrophobic homopolymers of native α-L-amino acids at the air-water interface : A study by circular dichroism spectroscopy, atomic force microscopy, and surface balance experiments
Films of poly-L-leucine, poly-L-valine, and poly-L-isoleucine have been studied at the air-water interface by surface balance experiments. In addition, Langmuir-Blodgett (LB) films of these polypeptides deposited onto quartz and mica have been studied by circular dichroism (CD) spectroscopy and atomic force microscopy (AFM) to elucidate the effects of polypeptide conformation and spreading agent (
Mitophagy : From the dark into the spotlight
AFM study of lipid monolayers : III. Phase behavior of ceramides, cholesterol and fatty acids
The outer part of the skin, stratum corneum, is essential to the skin's barrier function. Monolayer and bulk phase behavior of stratum corneum model lipids have thus been studied. Domain formation in Langmuir-Blodgett monolayers of synthetic ceramides (C16CerIII and C24CerIII), cholesterol, and free fatty acids (lignoceric acid, C24:0, and palmitic acid, C16:0) were investigated by atomic force mi
Responding phospholipid membranes : Interplay between hydration and permeability
Osmotic forces are important in regulating a number of physiological membrane processes. The effect of osmotic pressure on lipid phase behavior is of utmost importance for the extracellular lipids in stratum corneum (the outer part of human skin), due to the large gradient in water chemical potential between the water-rich tissue on the inside, and the relative dry environment on the outside of th
Diffusion through a responding lamellar liquid crystal : A model of molecular transport across stratum corneum
The outer part of the skin, stratum corneum, has an architecture of keratin filled cells, the corneocytes, embedded in stacked lipid bilayers. The lamellar structure provides an effective barrier to passive diffusion of small molecules and prevents uncontrolled water loss. In this paper, we present a theoretical model for molecular diffusional transport over an oriented stack of liquid crystalline
Rectangular solid domains in ceramide-cholesterol monolayers - 2D crystals
Very small rectangular domains were observed by atomic force microscopy in binary monolayers of synthetic ceramides and cholesterol. When the cholesterol content is increased the domains are bigger although the rectangular shape is retained. The almost perfect shape of the domains indicates two-dimensional single ceramide crystals. Lipid domains in monolayers of this particular shape and size have
The skin barrier from a lipid perspective
This contribution summarises the results from a number of investigations undertaken in the spirit of the Domain Mosaic Model proposed by Forslind in 1994. Atomic Force Microscopy (AFM) studies on the two-dimensional phase behaviour of some stratum corneum lipids revealed phase separation of the lipids in the typical case and the ability of cholesterol to reduce the line tension between phases. A t
Development of supramolecular structure through alkylation of pendant pyridyl functionality
The complex 12+ which has two pendant 4-pyridyl substituents may be viewed as a metal-containing analogue of 4,4′-bipyridine. The complex undergoes N-alkylation reactions with a variety of alkylating agents to give more highly functionalised tetracationic complexes which may be termed metalloviologens by analogy with viologens. These complexes may also be prepared by alkylation of the free ligands
Reaction of [Os3H2(CO)10] with the diyne Me3SiC2C2SiMe3 and the reactivity of the products towards [Co2(CO)8] : The X-ray structures of [Os3(μ-H)(CO)10 {μ-η1-η2-HC2 (SiMe3)C2(SiMe3)}],[Os3
The reaction of [Os3H2(CO)10] with Me3SiC2C2SiMe3 affords both [Os3(μ-H) (CO)10{μ-η1-η2-HC 2(SiMe3)C2(SiMe3)}] (1) and [Os3(μ-CO)(CO)9(μ3-η 2-Me3SiC2C2SiMe3)] (2) in good yield, 2 being favoured with an excess of diyne. In 1, one edge of the triosmium unit is bridged by the vinyl moiety of a transformed bis(trimethylsilyl)-1,4-butadiyne ligand that has undergone a hydride transfer and a 1,2-trimet
The effect of cholesterol on fatty acid monolayers
AFM study of lipid monolayers. 2. Effect of cholesterol on fatty acids
In this study the effect of cholesterol in Langmuir-Blodgett monolayers of fatty acids of varying chain lengths was investigated by atomic force microscopy (AFM). Domain formation due to lateral phase separation was studied at different lipid compositions and surface pressures. A small amount of cholesterol is miscible with palmitic acid (C16:0) and forms a flat monolayer while excess cholesterol
AFM study of lipid monolayers. 1. Pressure-induced phase behavior of single and mixed fatty acids
Monolayers of palmitic (C16:0) and lignoceric acid (C24:0) and their equimolar mixture were transferred to a hydrophilic mica substrate at various surface pressures and investigated by means of atomic force microscopy (AFM) in contact and lateral force modes. The first-order transition of lignoceric acid gives a plateau region, representing a liquid expanded to liquid condensed phase transition in
Dear territory or dear partner? Causes and consequences of breeding dispersal in a highly territorial bird of prey with a strong pair bond
Abstract: Territorial species are unlikely to show extensive movements between breeding seasons. This is especially true for long-lived species, which often have strong pair bonding and can occupy the same territory for years. However, also in such species, individuals may face situations that can lead to a territory shift. Here, we use a comprehensive dataset documenting 40 years of breeding beha
Impacts of large-scale Saharan solar farms on the global terrestrial carbon cycle
Amassing the available solar energy over the Sahara desert, through the installation of a large-scale solar farm, would satisfy the world’s current electricity needs. However, such land use changes may affect the global carbon cycle, possibly offsetting mitigation efforts. Here a fully coupled Earth System model EC-Earth was used to investigate the impact of a Saharan solar farm on the terrestrial
Metoprolol disrupts inflammatory response of human cardiomyocytes via β-arrestin2 biased agonism and NF-κB signaling modulation
Aims: Recent evidence supports non-class cardioprotective effects of metoprolol against neutrophil-mediated ischemia-reperfusion injury during exacerbated inflammation. Whether metoprolol exerts direct anti-inflammatory effect on cardiomyocytes is unknown. Accordingly, we aimed to investigate the direct anti-inflammatory effects of metoprolol in a cellular model of human induced pluripotent stem c
