Aggregation and Disaggregation of Humic Supramolecular Assemblies by NMR Diffusion Ordered Spectroscopy (DOSY-NMR)

2008 ◽  
Vol 42 (3) ◽  
pp. 699-706 ◽  
Author(s):  
Daniela Šmejkalová ◽  
Alessandro Piccolo
2015 ◽  
Vol 1099 ◽  
pp. 174-180 ◽  
Author(s):  
I.A. Khodov ◽  
G.A. Alper ◽  
G.M. Mamardashvili ◽  
N.Zh. Mamardashvili

1969 ◽  
Vol 22 (03) ◽  
pp. 496-507 ◽  
Author(s):  
W.G van Aken ◽  
J Vreeken

SummaryCarbon particles cause platelet aggregation in vitro and in vivo. Prior studies established that substances which modify thrombocyte aggregation also influence the rate at which carbon is cleared from the blood.This study was performed in order to elucidate the mechanism by which the carbon-platelet aggregates specifically accumulate in the RES.Activation of fibrinolysis by urokinase or streptokinase reduced the carbon clearance rate, probably due to generated fibrinogen degradation products (FDP). Isolated FDP decreased the carbon clearance and caused disaggregation of platelets and particles in vitro. Inhibition of fibrinolysis by epsilon-amino-caproic acid (EACA), initially accelerated the disappearance of carbon and caused particle accumulation outside the RES, predominantly in the lungs. It is supposed that platelet aggregation and locally activated fibrinolysis act together in the clearance of particles. In the normal situation the RES with its well known low fibrinolytic activity, becomes the receptor of the particles.


1972 ◽  
Vol 27 (01) ◽  
pp. 114-120 ◽  
Author(s):  
A. A Hassanein ◽  
Th. A El-Garf ◽  
Z El-Baz

SummaryADP-induced platelet aggregation and calcium-induced platelet aggregation tests were studied in 14 diabetic patients in the fasting state and half an hour after an intravenous injection of 0.1 unit insulin/kg body weight. Platelet disaggregation was significantly diminished as compared to a normal control group, and their results were negatively correlated with the corresponding serum cholesterol levels. Insulin caused significant diminution in the ADP-induced platelet aggregation as a result of rapid onset of aggregation and disaggregation. There was also a significant increase in platelet disaggregation. In the calcium-induced platelet aggregation test, there was a significant shortening of the aggregation time, its duration, and the clotting time. The optical density fall due to platelet aggregation showed a significant increase. Insulin may have a role in correcting platelet disaggregation possibly through improvement in the intracellular enzymatic activity.


2019 ◽  
Author(s):  
Nancy Watfa ◽  
Weimin Xuan ◽  
Zoe Sinclair ◽  
Robert Pow ◽  
Yousef Abul-Haija ◽  
...  

Investigations of chiral host guest chemistry are important to explore recognition in confined environments. Here, by synthesizing water-soluble chiral porous nanocapsule based on the inorganic metal-oxo Keplerate-type cluster, {Mo<sub>132</sub>} with chiral lactate ligands with the composition [Mo<sub>132</sub>O<sub>372</sub>(H<sub>2</sub>O)<sub>72</sub>(<i>x-</i>Lactate)<sub>30</sub>]<sup>42-</sup> (<i>x</i> = D or L), it was possible to study the interaction with a chiral guest, L/D-carnitine and (<i>R</i>/<i>S</i>)-2-butanol in aqueous solution. The enantioselective recognition was studied by quantitative <sup>1</sup>H NMR and <sup>1</sup>H DOSY NMR which highlighted that the chiral recognition is regulated by two distinct sites. Differences in the association constants (K) of L- and D-carnitine, which, due to their charge, are generally restricted from entering the interior of the host, are observed, indicating that their recognition predominantly occurs at the surface pores of the structure. Conversely, a larger difference in association constants (K<i><sub>S</sub></i>/K<i><sub>R</sub></i> = 3) is observed for recognition within the capsule interior of (<i>R</i>)- and (<i>S</i>)-2-butanol.


2018 ◽  
Vol 25 (19) ◽  
pp. 2272-2290 ◽  
Author(s):  
Aafrin M. Pettiwala ◽  
Prabhat K. Singh

Background: Amino acids are crucially involved in a myriad of biological processes. Any aberrant changes in physiological level of amino acids often manifest in common metabolic disorders, serious neurological conditions and cardiovascular diseases. Thus, devising methods for detection of trace amounts of amino acids becomes highly elemental to their efficient clinical diagnosis. Recently, the domain of developing optical sensors for detection of amino acids has witnessed significant activity which is the focus of the current review article. Methods: We undertook a detailed search of the peer-reviewed literature that primarily deals with optical sensors for amino acids and focuses on the use of different type of materials as a sensing platform. Results: Ninety-five papers have been included in the review, majority of which deal with optical sensors. We attempt to systematically classify these contributions based on the applications of various chemical and biological scaffolds such as polymers, supramolecular assemblies, nanoparticles, DNA, heparin etc for the sensing of amino acids. This review identifies that supramolecular assemblies and nanomaterial continue to be commonly used platforms to devise sensors for amino acids followed by surfactant assemblies. Conclusion: The broad implications of amino acids in human health and diagnosis have stirred a lot of interest to develop optimized optical detection systems for amino acids in recent years, using different materials based on chemical and biological scaffolds. We have also attempted to highlight the merits and demerits of some of the noteworthy sensor systems to instigate further efforts for constructing amino acids sensor based on unconventional concepts.


2021 ◽  
Vol 259 ◽  
pp. 124170
Author(s):  
Carolyn F. Graverson ◽  
Katherine M. Wortman-Otto ◽  
Abigail N. Linhart ◽  
Yasa Sampurno ◽  
Ara Philipossian ◽  
...  

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