Search results for "Arid"
showing 10 items of 1382 documents
Photo-Cross-Linked Hydrogels with Polysaccharide−Poly(amino acid) Structure: New Biomaterials for Pharmaceutical Applications
2006
The aim of this work has been the preparation and characterization of novel hydrogels with polysaccharide-poly(amino acid) structure having suitable physicochemical properties for pharmaceutical applications. In the first step, hyaluronic acid (HA) and alpha,beta-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA) have been derivatized with methacrylic anhydride (AMA), thus obtaining HA-AMA and PHM derivatives, respectively. In the second step, aqueous solutions of both these derivatives have been irradiated at 313 nm to obtain chemical hydrogels. The hydrogel obtained by irradiating for 15 min an aqueous solution containing 4% w/v of HA-AMA and 4% w/v of PHM resulted in the highest yield. Its swe…
The Effect of Calcium on the Cohesive Strength and Flexural Properties of Low-Methoxyl Pectin Biopolymers.
2019
Abstract: Pectin binds the mesothelial glycocalyx of visceral organs, suggesting its potential role as a mesothelial sealant. To assess the mechanical properties of pectin films, we compared pectin films with a less than 50% degree of methyl esterification (low-methoxyl pectin, LMP) to films with greater than 50% methyl esterification (high-methoxyl pectin, HMP). LMP and HMP polymers were prepared by step-wise dissolution and high-shear mixing. Both LMP and HMP films demonstrated a comparable clear appearance. Fracture mechanics demonstrated that the LMP films had a lower burst strength than HMP films at a variety of calcium concentrations and hydration states. The water content also influe…
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2001
Translational diffusion coefficients of volatile compounds in various aqueous solutions at low and subzero temperatures.
2005
International audience; Translational diffusion coefficients (D(12)) of volatile compounds were measured in model media with the profile concentration method. The influence of sample temperature (from 25 to -10 degrees C) was studied on translational diffusion in sucrose or maltodextrin solutions at various concentrations. Results show that diffusivity of volatile compounds in sucrose solutions is controlled by temperature, molecule size, and the viscosity of the liquid phase as expected with the Stokes-Einstein equation; moreover, physicochemical interactions between volatile compounds and the medium are determinant for diffusion estimation. At negative temperature, the winding path induce…
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL)-linker in the synthesis of glycopeptide partial structures of complex cell surface glycoproteins.
2003
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL) linker represents a novel fluoride-sensitive anchor for the solid-phase synthesis of protected peptides and glycopeptides. Its cleavage is achieved under almost neutral conditions using tetrabutylammonium fluoride trihydrate in dichloromethane thus allowing the construction of complex molecules sensitive to basic and acidic media commonly required for the cleavage of standard linker systems. The advantages of the PTMSEL linker are demonstrated in the synthesis of glycopeptides from the liver intestine (LI)-cadherin and the mucin MUC1, bearing carbohydrate moieties such as N-linked chitobiose or O-linked sialyl-T(N)-residues. The synthesis of the…
Multiple reaction monitoring for identification and quantification of oligosaccharides in legumes using a triple quadrupole mass spectrometer.
2022
Raffinose family oligosaccharides are non-digestible compounds considered as dietary prebiotics with health-related properties. Hence, it is important to develop highly specific methods for their determination. An analytical method is developed in this study for oligosaccharide identification and quantification using liquid chromatography-tandem mass spectrometry equipped with a triple quadrupole analyser operating in Multiple Reaction Monitoring mode. Raffinose, stachyose and verbascose are separated in a 10-minute run and the method is validated over a broad concentration range, showing good linearity, accuracy, precision and high sensitivity. A low-cost, short eco-friendly procedure for …
Quasispecies dynamics and molecular evolution of human norovirus capsid P region during chronic infection.
2009
In this novel study, we have for the first time identified evolutionarily conserved capsid residues in an individual chronically infected with norovirus (GGII.3). From 2000 to 2003, a total of 147 P1-1 and P2 capsid sequences were sequenced and investigated for evolutionarily conserved and functionally important residues by the evolutionary trace (ET) algorithm. The ET algorithm revealed more absolutely conserved residues (ACR) in the P1-1 domain (47/53, 88 %) as compared with the P2 domain (86/133, 64 %). The capsid P1-1 and P2 domains evolved in time-dependent manner, with a distinct break point observed between autumn/winter of year 2000 (isolates P1, P3 and P5) and spring to autumn of y…
Chionaeosides A–D, Triterpene Saponins from Paronychia chionaea
2007
Four new triterpenoid saponins, chionaeosides A-D (1-4) were isolated from the roots of Paronychia chionaea. On the basis of their spectroscopic data, the structures of the new saponins were established as 3-O-alpha-L-arabinopyranosylgypsogenic acid 28-O-beta-D-glucopyranosyl-(1--3)-beta-D-glucopyranosyl-(1--6)-beta-D-glucopyranoside (1), 3-O-alpha-L-arabinopyranosylgypsogenic acid 28-O-beta-D-glucopyranosyl-(1--6)-beta-D-glucopyranoside (2), 3-O-alpha-L-arabinopyranosylgypsogenic acid 28-O-beta-D-glucopyranoside (3), and 3-O-alpha-L-arabinopyranosylgypsogenic acid (4).
Triterpene Glycosides from the Roots of Astragalus flavescens
2007
Six new triterpene saponins, 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (1), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (2), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (3), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (4), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzus…