Search results for "OLIGOMERS"

Assessing the MALDI-TOF MS sample preparation procedure to analyze the influence of thermo-oxidative ageing and thermo-mechanical degradation on poly…

2011

[EN] Multiple processing by means of successive injection cycles was used to simulate the thermo-mechanical degradation effects on the oligomeric distribution of PLA under mechanical recycling. Likewise, an accelerated thermal ageing over PLA glass transition was performed in order to simulate its service life. MALDI-TOF MS was used for the analysis and the sample preparation procedure was assessed by means of a statistical Design of Experiments (DoE). The quality effects in use for the analysis were signal-to-noise ratio and Resolution. Different matrixes, analyte/matrix proportions and the use of NaTFA as cationization agent were considered. A deep inspection of the statistical results pr…

Weak Interactions Modulating the Dimensionality in Supramolecular Architectures in Three New Nickel(II)-Hydrazone Complexes, Magnetostructural Correl…

2011

Three different ONO donor acetyl hydrazone Schiff bases have been synthesized from the condensation of acetic hydrazide with three different carbonyl compounds: salicylaldehyde (HL(1)), 2-hydroxyacetophenone (HL(2)), and 2, 3-dihydroxybenzaldehyde (HL(3)). These tridentate ligands are reacted with Ni(OOCCF(3))(2)·xH(2)O to yield three new Ni(II) complexes having distorted octahedral geometry at each Ni center: [Ni(L(1))(OOCCF(3))(CH(3)OH)](2) (1), [Ni(L(2))(OOCCF(3))(H(2)O)](2) (2), and [Ni(L(3))(L(3)H)](OOCCF(3))(H(2)O)(1.65)(CH(3)OH)(0.35) (3). The ligands and the complexes have been characterized by elemental analysis and IR and UV-vis spectroscopy, and the structures of the complexes ha…

Small Molecules Targeting and Modulating Toxic Tau Oligomeric Strains

Alzheimer’s disease (AD) is one of over 18 different disorders known as tauopathies, characterized by the pathological aggregation and accumulation of tau, a microtubule-associated protein. Tau aggregates are heterogeneous and can be divided into two major groups: large metastable neurofibrillary tangles (NFTs) and oligomers. Recently, it has been shown that tau oligomers are highly toxic in vitro and efficient seeds for the propagation of pathology as compared to NFTs. While the toxicity of recombinant tau oligomers has been studied extensively, within the same aggregation state, tau exhibits conformational differences, termed tau oligomeric strains. Due to the dynamic nature of these stra…

Microglia and α-synuclein implication in Parkinson's disease

2011

Age-related neurodegenerative disorders like Parkinson’s disease take an enormous toll on individuals and on society. Despite extensive efforts, Parkinson’s disease remains incurable and only very limited treatments exist. Indeed, Parkinson’s pathogenesis is still not clear and research on its molecular mechanisms is ongoing. In this study, we focused our interest on two abnormal events occurring in Parkinson’s patients, namely α-synuclein aggregation and microglial activation. We first investigated α-synuclein and its abnormal polymerisation. For this purpose, we developed novel methods, which allowed the in vitro production of different types of α-synuclein oligomers. Using highly sensiti…

Role of Alkyl Substituent and Solvent on the Structural, Thermal, and Magnetic Properties of Binary Radical Salts of 1,2,3,5-Dithia- or Diselenadiazo…

2022

The synthesis, structural, thermal, and magnetic properties of a series of simple binary organic salts based on the radical anion of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 4-(N-alkylpyridinium-3-yl)-1,2,3,5-dithiadiazolyl (DTDA), 1R (R = Et, Pr, Bu), radical cations and their heavier selenium analogues (DSDA), 2R, are described. Single-crystal X-ray structural analyses reveal that short alkyl substituents on the pyridinium moiety of DTDA/DSDA cations lead to crystallization of isostructural acetonitrile (MeCN) solvates 1Et·MeCN, 1Pr·MeCN, 2Et·MeCN, and 2Pr·MeCN with trans-cofacial DTDA radical cation and eclipsed-cofacial TCNQ radical anion dimers. A slight increase in the substituent …

Fibrillogenesis of hen egg-white lysozyme at acidic pH

2009

Role of electrostatic interactions in the fibrillogenesis of lysozyme

2011

(E)-2-cyano-3-(5'-piperidin-1-yl-2,2'-bithien-5-yl)acrylic acid: a new fluorescent probe for detecting prefibrillar oligomers

2013

Efficient stabilisation of a dihydrogenphosphate tetramer and a dihydrogenpyrophosphate dimer by a cyclic pseudopeptide containing 1,4-disubstituted …

2017

A cyclic pseudooctapeptide 2 is described containing 1,4-disubstituted 1,2,3-triazole moieties. This compound features eight converging hydrogen bond donors along the ring, namely four amide NH and four triazole CH groups, which enable 2 to engage in interactions with anions. While fully deprotonated sulfate anions exhibit only moderate affinity for 2, protonated anions such as dihydrogenpyrophosphate and dihydrogenphosphate anions are strongly bound. Complexation of the phosphate-derived anions involves sandwiching of a dihydrogenpyrophosphate dimer or a dihydrogenphosphate tetramer between two pseudopeptide rings. X-ray crystallography provided structural information, while 1H NMR spectro…

Selective Synthesis of Z -Silyl Enol Ethers via Ni-Catalyzed Remote Functionalization of Ketones

2021

Journal of the American Chemical Society : JACS 143(22), 8375-8380 (2021). doi:10.1021/jacs.1c01797