Search results for "TRIX"

Polyaminocyclodextrin nanosponges: synthesis, characterization and pH-responsive sequestration abilities

2016

New pH-responsive nanosponges were obtained by reacting four different polyaminocyclodextrins with heptakis-(6-bromo)-(6-deoxy)-β-cyclodextrin. The materials obtained were characterized by various techniques (FT-IR, potentiometric titration, differential scanning calorimetry (DSC), porosimetry (BET), 13C{1H} CP-MAS NMR). Their adsorption abilities at different pH values were verified towards a suitable set of model guests, and seem mainly controlled by electrostatic interactions, as a function of the protonation/charge status of the polymer matrix. By contrast, data positively point out a lesser importance assumed by the induced-fit effect, important in affecting the formation of host–guest…

Nautilin-63, a novel acidic glycoprotein from the shell nacre of Nautilus macromphalus

2011

In molluscs, and more generally in metazoan organisms, the production of a calcified skeleton is a complex molecular process that is regulated by the secretion of an extracellular organic matrix. This matrix constitutes a cohesive and functional macromolecular assemblage, containing mainly proteins, glycoproteins and polysaccharides that, together, control the biomineral formation. These macromolecules interact with the extruded precursor mineral ions, mainly calcium and bicarbonate, to form complex organo-mineral composites of well-defined microstructures. For several reasons related to its remarkable mechanical properties and to its high value in jewelry, nacre is by far the most studied …

UV-patternable nanocomposite containing CdSe and PbS quantum dots as miniaturized luminescent chemo-sensors

2015

In this study, a novel multifunctional hybrid polymer-based luminescent material, particularly formulated for photolithography, was developed, fabricated and tested as a miniaturized chemosensor. This nanocomposites were formulated with either luminescent CdSe (for the visible) or PbS (for the near-IR) colloidal QDs embedded in a polyisoprene-based photoresist (PIP). We checked the sensing capability of the nanocomposite by exposing 1 cm2 CdSe nanocomposite patterns to vapours of some analyte solutions such as 2-mercaptoethanol (MET) and ethylenediamine (EDA). The transduction mechanism of the sensor is based on changes of the QD photoluminescence (PL) when molecules are adsorbed on the QD …

Influence of dissolved humic material and ionic strength on C8 extraction of pesticides from water

1995

A mixture of twelve intermediate polarity pesticides, mostly carbamate-type, have been chromatographied on an octadecyl-silica bonded-phase column using acetonitrile-water gradient mobile phase and UV detection. Pesticides were extracted from aqueous matrix by solid-phase extraction. The extraction system consisted of a glass microcolumn containing octyl-silica solidphase conditioned with methanol and water. The elution was by acetonitrile-dichloromethane (50:50). Studies of extraction factors like volume of sample, addition of 10% sodium chloride and presence of dissolved humic material are investigated.

2019

Molecular complexes between glycolic acid and nitrogen were studied in a low-temperature argon matrix with FTIR spectroscopy, and supported by MP2 and BLYPD3 calculations. The calculations indicate 11 and 10 stable complex structures at the MP2 and BLYPD3 levels of theories, respectively. However, only one hydrogen-bonded complex structure involving the most stable SSC conformer of glycolic acid was found experimentally, where the nitrogen molecule is bound with the carboxylic OH group of the SSC conformer. The complex shows a rich site structure variation upon deposition of the matrix in different temperatures and upon annealing experiments, which provide interesting prospects for site-sel…

Hydrolytic degradation of PLA/Posidonia Oceanica green composites: A simple model based on starting morpho-chemical properties

2021

Abstract In this work, we studied the degradability of PLA-based biocomposites containing Posidonia Oceanica flour at different loading levels and aspect ratios. Hydrolytic tests were carried out in neutral (pH = 7.4) and alkaline (pH = 10) environment. Time-dependent evolution of some key features, including residual mass and solution uptake, was monitored, and correlated with the changes observed in both morphology and chemical structure of the matrix. The results pointed out that biocomposites degraded much faster than neat PLA in both conditions, up to lose 70% of their initial weight after 1000 h immersion. A complex mechanism was unveiled, evidencing the crucial role of the fillers, c…

Patterns of expression of trichocytic and epithelial cytokeratins in mammalian tissues

1988

Abstract Cells forming hair and nail material are characterized by the synthesis of members of a particular group of α-keratin polypeptides (trichocytic cytokeratins, “T cytokeratins”) different from epithelial cytokeratins (“E cytokeratins”). As the precursor cells to trichocytes are derived from fetal epidermal keratinocytes expressing only E cytokeratins, we have studied the patterns of expression of both T and E cytokeratins in developing human hair-and nailforming tissues of different fetal stages, by immunocyto-chemistry using antibodies specific for certain T or E cytokeratins and by two-dimensional gel electrophoresis and immunoblotting. In developing hair follicles up to the early …

Relationships Between Dimorphism, Cell Wall Structure, and Surface Activities in Candida albicans

1991

Most cells are covered with a complex network of interacting molecules that form the extracellular matrix. These molecules (proteins and polysaccharides) are secreted locally and interact among themselves to form an organized structure outside the cell plasma membrane. In unicellular eukaryotic organisms and plant cells, this structure is reinforced to withstand osmotic changes in the external environment, giving rise to the so-called cell wall.

Selective extraction of small proteins from biological samples using a novel restricted access column with cation exchange properties

2000

The determination of proteins utilising a polymer-based restricted access suppor material with ion exchange properties (IERAM) is outlined. Solid phase extraction coupled on-line with a mincrobore reversed phase HPLC system for the quantitation of small marker proteins is demonstrated. The cation-exchange restricted access packings were characterised with respect to their adsorption and desorption kinetics. The IERAM material was also investigated by capacity, selectivity, and biocompatibility determinations when applied to the quantification of small molecular weight proteins such as cytochrome C, Lysozyme, Ribonuclease A, Myoglobin, Insulin, human serum albumin, and a Tryptic inhibitor.

Modifying the reactivity of copper (II) by its encapsulation into polydimethylsiloxane: A selective sensor for ephedrine-like compounds

2018

This paper demonstrates that the reactivity of copper (II) can be modified through its entrappment in a polymeric matrix of polydimethylsiloxane (PDMS), which makes possible the reaction into the support instead of in solution. Amino-containing compounds such as amino acids, proteins and sugars, which react with Cu (II) in solution, do not react inside the polymer. As a prove of concept, a highly specific Cu (II) PDMS-based sensor for ephedrines has been developed in this work. When the sensors are put into contact with solutions of these drugs under basic conditions, a change in their color from pale green to purple is observed. This change enables the visual identification of ephedrine (E…