Results 1 - 10
of
11
Characterization of oxidized tannins: comparison of depolymerization methods, asymmetric flow field-flow fractionation and small-angle X-ray scattering Céline Poncet-Legrand
"... Abstract Condensed tannins are a major class of plant polyphenols. They play an important part in the colour and taste of foods and beverages. Due to their chemical reactivity, tannins are not stable once extracted from plants. A number of chemical reactions can take place, leading to structural ch ..."
Abstract
- Add to MetaCart
(Show Context)
Abstract Condensed tannins are a major class of plant polyphenols. They play an important part in the colour and taste of foods and beverages. Due to their chemical reactivity, tannins are not stable once extracted from plants. A number of chemical reactions can take place, leading to structural changes of the native structures to give so-called derived tannins and pigments. This paper compares results obtained on native and oxidized tannins with different techniques: depolymerization followed by high-performance liquid chromatography analysis, small-angle X-ray scattering (SAXS) and asymmetric flow field-flow fractionation (AF4). Upon oxidation, new macromolecules were formed. Thioglycolysis experiments showed no evidence of molecular weight increase, but thioglycolysis yields drastically decreased. When oxidation was performed at high concentration (e.g., 10 gL −1 ), the weight average degree of polymerization determined from SAXS increased, whereas it remained stable when oxidation was done at low concentration (0.1 gL −1 ), indicating that the reaction was intramolecular, yet the conformations were different. Differences in terms of solubility were observed; ethanol being a better solvent than water. We also separated soluble and non-water-soluble species of a much oxidized fraction. Thioglycolysis showed no big differences between the two fractions, whereas SAXS and AF4 showed that insoluble macromolecules have a weight average molecular weight ten times higher than the soluble ones.
JCB Article
"... Uroplakin IIIb, a urothelial differentiation marker, dimerizes with uroplakin Ib as an early step of urothelial plaque assembly ..."
Abstract
- Add to MetaCart
Uroplakin IIIb, a urothelial differentiation marker, dimerizes with uroplakin Ib as an early step of urothelial plaque assembly
Biomacromolecules XXXX, xxx, 000 A Breakdown of Cell Wall Nanostructure in Dilute Acid Pretreated
, 2010
"... The generation of bioethanol from lignocellulosic biomass holds great promise for renewable and clean energy production. A better understanding of the complex mechanisms of lignocellulose breakdown during various pretreatment methods is needed to realize this potential in a cost and energy efficient ..."
Abstract
- Add to MetaCart
The generation of bioethanol from lignocellulosic biomass holds great promise for renewable and clean energy production. A better understanding of the complex mechanisms of lignocellulose breakdown during various pretreatment methods is needed to realize this potential in a cost and energy efficient way. Here we use smallangle neutron scattering (SANS) to characterize morphological changes in switchgrass lignocellulose across molecular to submicrometer length scales resulting from the industrially relevant dilute acid pretreatment method. Our results demonstrate that dilute acid pretreatment increases the cross-sectional radius of the crystalline cellulose fibril. This change is accompanied by removal of hemicellulose and the formation of Rg ∼ 135 Å lignin aggregates. The structural signature of smooth cell wall surfaces is observed at length scales larger than 1000 Å, and it remains remarkably invariable during pretreatment. This study elucidates the interplay of the different biomolecular components in the breakdown process of switchgrass by dilute acid pretreatment. The results are important for the development of efficient strategies of biomass to biofuel conversion.
DOI 10.1007/s00396-011-2421-0 ORIGINAL CONTRIBUTION Morphology and photoluminescence study of titania nanoparticles
"... # The Author(s) 2011. This article is published with open access at Springerlink.com Abstract Titania nanoparticles are prepared by sol–gel chemistry with a poly(ethylene oxide) methyl ether methacrylate-block-poly(dimethylsiloxane)-block-poly (ethylene oxide) methyl ether methacrylate triblock copo ..."
Abstract
- Add to MetaCart
# The Author(s) 2011. This article is published with open access at Springerlink.com Abstract Titania nanoparticles are prepared by sol–gel chemistry with a poly(ethylene oxide) methyl ether methacrylate-block-poly(dimethylsiloxane)-block-poly (ethylene oxide) methyl ether methacrylate triblock copolymer acting as the templating agent. The sol–gel components—hydrochloric acid, titanium tetraisopropoxide, and triblock copolymer—are varied to investigate their effect on the resulting titania morphology. An increased titania precursor or polymer content yields smaller primary titania
Nano-Scale Morphology of Melanosomes Revealed by Small-Angle X-Ray Scattering
"... Melanosomes are highly specialized organelles that produce and store the pigment melanin, thereby fulfilling essential functions within their host organism. Besides having obvious cosmetic consequences – determining the color of skin, hair and the iris – they contribute to photochemical protection f ..."
Abstract
- Add to MetaCart
(Show Context)
Melanosomes are highly specialized organelles that produce and store the pigment melanin, thereby fulfilling essential functions within their host organism. Besides having obvious cosmetic consequences – determining the color of skin, hair and the iris – they contribute to photochemical protection from ultraviolet radiation, as well as to vision (by defining how much light enters the eye). Though melanosomes can be beneficial for health, abnormalities in their structure can lead to adverse effects. Knowledge of their ultrastructure will be crucial to gaining insight into the mechanisms that ultimately lead to melanosome-related diseases. However, due to their small size and electron-dense content, physiologically intact melanosomes are recalcitrant to study by common imaging techniques such as light and transmission electron microscopy. In contrast, X-ray-based methodologies offer both high spatial resolution and powerful penetrating capabilities, and thus are well suited to study the ultrastructure of electron-dense organelles in their natural, hydrated form. Here, we report on the application of small-angle X-ray scattering – a method effective in determining the three-dimensional structures of biomolecules – to whole, hydrated murine melanosomes. The use of complementary information from the scattering signal
DOI 10.1186/s13068-015-0422-9
"... Multi-scale processes of beech wood disintegration and pretreatment with 1-ethyl-3-methylimidazolium acetate/water mixtures ..."
Abstract
- Add to MetaCart
(Show Context)
Multi-scale processes of beech wood disintegration and pretreatment with 1-ethyl-3-methylimidazolium acetate/water mixtures
ARTICLE
"... Cooperative folding of intrinsically disordered domains drives assembly of a strong elongated protein ..."
Abstract
- Add to MetaCart
Cooperative folding of intrinsically disordered domains drives assembly of a strong elongated protein
