Search results for " change"
showing 10 items of 3731 documents
The chemistry of death--Adipocere degradation in modern graveyards.
2015
The formation of adipocere slows further decomposition and preserves corpses for decades or even centuries. This resistance to degradation is a serious problem, especially with regard to the reuse of graves after regular resting times. We present results from an exhumation series in modern graveyards where coffins from water-saturated earth graves contained adipocere embedded in black humic material after resting times of about 30 years. Based on the assumption that this humic material resulted from in situ degradation of adipocere, its presence contradicts the commonly held opinion that adipocere decomposition only occurs under aerobic conditions. To test our hypothesis, we collected black…
Cooperative symmetric to asymmetric conformational transition of the apo-form of scavenger decapping enzyme revealed by simulations.
2007
Decapping is a central step in eukaryotic mRNA turnover and in gene expression regulation. The human scavenger decapping enzyme, DcpS, catalyses cap hydrolysis following mRNA degradation. DcpS is a dimeric enzyme, with two active sites. Crystal structures suggest that DcpS must undergo significant conformational changes upon ligand binding, but the mechanism of this transition is unknown. Here, we report two long timescale (20 ns) molecular dynamics simulations of the apo-form of DcpS. The dimer is observed to undergo a strikingly cooperative motion, with one active site closing while the other opens. The amplitude of the conformational change is 6–21 A and the apparent timescale is 4–13 ns…
On new chemical reactions of polymers
1968
Three major areas of work present themselves to a chemist who is concerned with polymer materials namely: synthesis and degradation of polymers; structure analysis of natural and synthetic polymers; and chemical transformations of polymers. Although these three fields are very closely related, I wish to concern myself only with the last of them.
In vivo analysis of noise dependent activation of white blood cells and microvascular dysfunction in mice
2021
This article contains supporting information on data collection for the research article entitled “Aircraft noise exposure drives the activation of white blood cells and induces microvascular dysfunction in mice” by Eckrich et al. We found that noise-induced stress triggered microvascular dysfunction via involvement of innate immune-derived reactive oxygen species. In this article, we present the instrumentation of mice with dorsal skinfold chambers for in vivo microscopic imaging of blood flow, interaction of leukocytes with the vascular wall (also by fluorescent labelling of blood cells) and vessel diameter. In addition, we explain the preparation of cerebral arterioles for measurement of…
On the use of multi-parameter free energy relationships: the rearrangement of (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole into (2-aryl-5…
2010
Abstract By using a multi-parameter approach (a combination of Hammett/Ingold-Yukawa-Tsuno/Fujita-Nishioka free energy relationships) the mononuclear rearrangements of heterocycles (MRH) rates for five new ortho-substituted and ten new di-, tri-, or tetra-substituted (Z)-arylhydrazones of 5-amino-3-benzoyl-1,2,4-oxadiazole into the relevant (2-aryl-5-phenyl-2H-1,2,3-triazol-4-yl)ureas (in dioxane/water and in a large range of pS+ values) have been related to the electronic and proximity effects exerted by the present substituents, also considering previous results on some mono meta- and para-substituted (Z)-arylhydrazones. In every case, excellent correlation coefficients have been calculat…
Structure and Conformational Studies of Aza-Crown 8-Amino-BODIPY Derivatives: Influence of Steric Hindrance on Their Photophysical Properties
2017
Herein, we report the synthesis, X-ray crystal structure and photophysical studies of six new 8-amino-BODIPY derivatives containing crown or azo-crown ether moieties. The influence of steric hindrance, caused by the crown ether, on the planarity of the BODIPY core and its relationship with the fluorescent properties has been established. 1H NMR spectroscopic studies were undertaken to clarify the changes in fluorescence observed in the presence of ZnII.
A Novel Zeolite-Induced Population of a Planar Viologen Conformation. New Viologen Charge Transfer Complexes and Alkene/Viologen/Zeolite Arrays
2004
A rare example of a novel zeolite-induced conformational change and a mechanism for this process are suggested in order to rationalize an unexpected spontaneous intrazeolite reduction observed during preparation of a new viologen (MQ2+)-doped zeolite (NaY). In addition, the formations of six new alkene/viologen/ zeolite charge transfer (CT) arrays using NaMQY and the previously reported NaMVY are also reported. The binding constants between MQ2+ and MV2+ and 2,3-dimethyl-2-butene (TME) were determined using the Benesi-Hildebrand approach, and the stabilities of these CT complexes are compared to their intrazeolite analogue.
Riverine impacts on benthic biodiversity and functional traits: A comparison of two sub-Arctic fjords
2020
Abstract Climate change is leading to increases in freshwater discharge to coastal environments with implications for benthic community structure and functioning. Freshwater inputs create strong environmental gradients, which potentially affect the community structure of benthic infauna. In turn, changes in functional trait composition have the potential to affect the processing of terrestrially-derived nutrients and organic matter along the freshwater to marine continuum. We investigated the effects of riverine inputs on benthic community structure, functional traits, taxonomic and functional diversity, and utilization of terrestrial organic matter in two contrasting northern Norwegian fjo…
Changes in ewe milk fatty acids following turning out to pasture
2008
Abstract Ten Comisana dairy ewes were selected to observe time of changing in milk fatty acids as a result of switching from stall to pasture feeding. At first, ewes were subjected to a stall-feeding period of 30 days (pre-experimental phase). After which, ewes were abruptly turned out to a vetch and oats pasture as their sole feed (experimental phase). Individual milk samples were collected on experimental days 0 (the last day of stall feeding), 1–4, 8, 11, 17 and 23. Milk and feeds fatty acid composition was determined by gas chromatography. The sudden passage from a stall to a pasture diet significantly modified the fatty acid profile of ewe milk. Medium- and long-chain fatty acids were …
Über die lösungswärme von polystyrol in verschiedenen lösungsmitteln
1951
An einem Polystyrol mit einem Molekulargewicht von ca. 20 000 werden die Losungs-warmen in verschiedenen Losungsmitteln in einem Kalorimeter bestimmt. Die meisten Losungsvorgange verlaufen exotherm, in einem Fall (Cyclohexan) wird jedoch bei der Auflosung Warme von der Umgebung aufgenommen. Es wird festgestellt, das die Trocknung der Praparate sehr wichtig fur die Reproduzierbarkeit der Messungen ist. Ferner wird orientierend die Abhangigkeit der Losungswarme vom Polymerisationsgrad sowie von der Konzentration der entstehenden Losung festgestellt. Es wird auserdem orientierend die Mischungswarme von Athylbenzol in verschiedenen Losungsmitteln bestimmt. Measurements of the heat of solution o…