Search results for "digestive"
showing 10 items of 2631 documents
Functional Polymer-Opals from Core-Shell Colloids
2007
Colloidal photonic crystals were prepared from monodisperse core-shell particles. The shell is hereby formed from a functional monomer, such as glycidylmethacrylate or different reactive ester monomers, which can perform chemical reactions and the core from a standard monomer, which yields highly monodisperse colloids. It was possible to crystallize the core-shell particles into artificial opals with excellent optical properties. Reactions on the functional surface of the colloids were carried out, which lead to a dramatic rise in the mechanical stability or to a functionalization of His-tagged silicatein, which acts as nanoreactor to synthesize and immobilize gold nanoparticles from auric …
Re-entrant glass transition in a colloid-polymer mixture with depletion attractions.
2002
Performing light scattering experiments we show that introducing short-ranged attraction to a colloidal suspension of nearly hard spheres by addition of free polymer produces new glass transition phenomena. We observe a dramatic acceleration of the density fluctuations amounting to the melting of a colloidal glass. Increasing the strength of the attractions the system freezes into another nonergodic state sharing some qualitative features with gel states occurring at lower colloid packing fractions. This reentrant glass transition is in qualitative agreement with recent theoretical predictions.
Controlling the wetting properties of the Asakura-Oosawa model and applications to spherical confinement.
2012
We demonstrate for the Asakura-Oosawa model and an extension of this model that uses continuous rather than hard potentials, how wetting properties at walls can be easily controlled. By increasing the interaction range of the repulsive wall potential acting on the colloids (while keeping the polymer-wall interactions constant) polymers begin to substitute colloids at walls and the system can be driven from complete wetting of colloids via partial wetting to complete wetting of polymers. As an application, we discuss the morphology and wetting behavior of colloid-polymer mixtures in spherical confinement. We apply the recently developed 'ensemble switch method' where the Hamiltonian is exten…
Salt and fat contents influence the microstructure of model cheeses, chewing/swallowing andin vivoaroma release
2013
The effects of the lipid/protein ratio (20/28, 24/24, 28/20) and salt content of model cheeses were investigated simultaneously with respect to chewing behaviour, swallowing events and in vivo aroma release. Chewing parameters were measured by electromyography. Swallowing events were recorded manually. In vivo aroma release was investigated using nose-space on-line atmospheric pressure chemical ionisation-mass spectrometry. The values for chewing activity and time before swallowing were higher with lower lipid/protein ratios and lower salt contents, due to the greater mechanical resistance of the model cheeses. The corresponding microstructure was made up of smaller and more circular fat dr…
Localization and Activity of a Carboxypeptidase in Germinating Seeds of Scots Pine, Pinus sylvestris
1976
Extracts prepared from the endosperm of germinating seeds of Scots pine, Pinus sylvestris L., hydrolysed two typical carboxypeptidase substrates, Z-Phe-Ala and Z-Phe-Phe, with pH optima at 4.2 and 5.0. The activities were completely destroyed by diisopropylfluorophosphate. Identical heat inactivation curves and elution patterns in gel chromatography on Sephadex G-200 suggest that the two activities are due to a single enzyme. In resting seeds very low carboxypeptidase activity was present in both the endosperm and the embryo. During germination on agar gel at 20°C in the dark the activities, expressed as enzyme units per seed, increased in the seedling and particularly in the endosperm up t…
Brownian dynamics simulation of grafted polymer brushes
1995
We present results of computer simulations by the method of Brownian dynamics of polymeric brushes attached to impenetrable planes. For testing both model and method we have used one polymer brush attached to a repulsive plane and compare some results with Monte Carlo results of Lai and Binder on the bond fluctuation model. We have also studied two polymeric brushes attached to two parallel planes at different distances between planes, and investigate the interplay between the interpenetration of the brushes and the configurational properties of the grafted chains.
Hydrodynamic mechanisms of spinodal decomposition in confined colloid-polymer mixtures: A multiparticle collision dynamics study
2013
A multiscale model for a colloid-polymer mixture is developed. The colloids are described as point particles interacting with each other and with the polymers with strongly repulsive potentials, while polymers interact with each other with a softer potential. The fluid in the suspension is taken into account by the multiparticle collision dynamics method (MPC). Considering a slit geometry where the suspension is confined between parallel repulsive walls, different possibilities for the hydrodynamic boundary conditions (b.c.) at the walls (slip versus stick) are treated. Quenching experiments are considered, where the system volume is suddenly reduced (keeping the density of the solvent flui…
Epidemiology and pathogenesis of celiac disease and non-celiac gluten (wheat) sensitivity
2021
Abstract While in the past, celiac disease (CD) was considered the only clinical entity caused by the ingestion of gluten-containing grains, now there is evidence that a spectrum of gluten-related disorders, including also wheat allergy and non-celiac gluten (wheat) sensitivity (NCGS/NCWS), exists. The prevalence of gluten-related disorders is rising, and increasing numbers of individuals are empirically trying a gluten-free diet for a variety of signs and symptoms. CD is a gluten-induced immune-mediated enteropathy characterized by a specific genetic genotype [human leukocyte antigen (HLA)-DQ2 and HLA-DQ8 genes] and autoantibodies (antitissue transglutaminase and antiendomysial). NCGS/NCWS…
Responses of soil carbon and nitrogen transformations to stump removal
2012
We studied in central Finland whether stump harvesting after clear felling of coniferous forest poses further short-term changes in soil carbon and nitrogen dynamics when compared to the traditional site preparation method, mounding. Exposed mineral soil patches in Norway spruce (Picea abies) dominated clear-cut stands were sampled 1â5 years after the treatments. The extent of the exposed mineral soil surface was significantly larger at the stump removal sites when compared to the mounding sites. No differences were found in soil pH, organic matter content or total concentration of soil C between the treatments or treatment years. Total concentration of soil N was consistently higher and …
Steviol Glycosides Stability after Pulsed Electric Technologies and Ultrasounds Treatments in Fruit Juice Blend Sweetened with Stevia rebaudiana
2016
Stevia rebaudiana bartoni due to its high content in steviol glycosides and the ability to serve as a natural antimicrobial to complement the effectiveness of pulsed electric technologies for food preservation, has been used more frequently to improve sensorial properties of liquid foods.