Search results for "Critical"
showing 10 items of 3024 documents
Calculation of phase diagrams not requiring the derivatives of the Gibbs energy demonstrated for a mixture of two homopolymers with the corresponding…
1995
A method is presented which allows the calculation of phase diagrams (spinodal, binodal and tie lines) on the basis of the Gibbs energy of mixing ΔG. No derivatives of ΔG with respect to the composition variables are required. This method is particularly useful in cases where the composition dependence of ΔG is very complex and no analytical representation of the derivatives can be given. The method is applied to a ternary mixture of two homopolymers with a copolymer consisting of the same monomers. The sequence distribution of the copolymer is kept constant between random and purely alternating, and phase diagrams are calculated for different chemical compositions of the copolymer. The com…
Self-assembly of bioelastomeric structures from solutions: Mean-field critical behavior and Flory-Huggins free energy of interactions
1993
Elastic and quasi-elastic light scattering studies were performed on aqueous solutions of poly (Val-Pro-Gly-Gly), a representative synthetic bioelastomer that differs from the previously studied poly (Val-Pro-Gly-Val-Gly) by the deletion of the hydrophobic Val in position four. When the spinodal line was approached from the region of thermodynamic stability, the intensity of light scattered by fluctuations, and the related lifetime and correlation length, were observed to diverge with mean-field critical exponents for both systems. Fitting of the experimental data allowed determining the spinodal and binodal (coexistence) lines that characterize the phase diagrams of the two systems, and it…
Demixing of unsheared and sheared solutions of polystyrene in tert-butylacetate and the pressure influence on their flow behaviour
1979
For the system tert-butyl acetate/polystyrene (M= 670000) the phase separation behaviour (upper critical solution temperatures, upper critical solution pressures) is investigated by means of visual and turbidimetric cloud-point measurements and by viscometry. For near-critical concentrations the visually determined cloud-points are found at higher, for low concentrations at lower temperatures as compared with the turbidimetrically determined binodal temperature,Tbin Plots of the invers of the turbidity measured atTbin as a function of the polymer concentration,w2, yield a minimum from which the critical composition can be determined. The viscometrically obtained demixing points (break-down …
Bio-inspired security analysis for IoT scenarios
2020
Computer security has recently become more and more important as the world economy dependency from data has kept growing. The complexity of the systems that need to be kept secure calls for new models capable of abstracting the interdependencies among heterogeneous components that cooperate at providing the desired service. A promising approach is attack graph analysis, however, the manual analysis of attack graphs is tedious and error prone. In this paper we propose to apply the metabolic network model to attack graph analysis, using three interacting bio-inspired algorithms: topological analysis, flux balance analysis, and extreme pathway analysis. A developed framework for graph building…
Modifying the body distribution of HPMA-based copolymers by molecular weight and aggregate formation.
2011
There is a recognized need to create well-defined polymer probes for in vivo and clinical positron emission tomography (PET) imaging to guide the development of new generation polymer therapeutics. Using the RAFT polymerization technique in combination with the reactive ester approach, here we have synthesized well-defined and narrowly distributed N-(2-hydroxypropyl)methacrylamide homopolymers (pHPMA) (P1* and P2*) and random HPMA copolymers consisting of hydrophilic HPMA and hydrophobic lauryl methacrylate comonomers (P3* and P4*). The polymers had molecular weights below (P1* and P3*) and above the renal threshold (P2* and P4*). Whereas the homopolymers dissolve in isotonic solution as in…
Oxygenation and Bioenergetic Status of Murine Fibrosarcomas
1992
The heterogeneity of cellular response to therapy is a major problem in non-surgical cancer therapy. This heterogeneity is influenced by both the genetic variability between different tumor cells and by epigenetic, physiological factors, such as the local metabolic milieu. A restriction of tumor microcirculation concomitant with regional hypoxia, nutrient depletion, accumulation of lactate, and an intensified tumor acidosis becomes evident during growth of many solid tumors1. These critical factors can greatly influence the efficiency of various non-surgical tumor therapies.
Quantifying biogeochemical heterogeneity in soil systems
2018
© 2018 Elsevier B.V. Soils are increasingly perceived as complex systems with properties and biogeochemical functions that vary on millimeter scales. Quantitative information about the resulting biogeochemical heterogeneity is needed to improve process knowledge and to render biogeochemical models more mechanistic. Here we demonstrate how standardized arrays of Pt-electrodes can be used to quantify biogeochemical or ‘functional’ soil heterogeneity, defined as the extent to which the soil is subdivided into microenvironments. Our case study confirmed the validity of this approach for a soil sequence consisting of a well-drained, a moderately well drained and a poorly drained Mollisol. We fou…
Potentials for critical raw materials recovery from Mediterranean saltworks bitterns
2022
Minerals extraction from seawater brines is currently regarded as the most practical approach to reduce European dependency from the import of many Critical Raw Materials. The technical feasibility of such approach has been widely demonstrated in several different research and development projects but the economic sustainability has always been found to depend on the local demand for sodium chloride, which is always the most abundant product of the extraction. Starting from this crucial node, the SEArcularMINE project has investigated the possibility to use the residual brines originated by sea-salt extraction in traditional saltworks, regarded as an already well-established marketplace. Th…
Chronic consumption of an inositol-enriched carob extract improves postprandial glycaemia and insulin sensitivity in healthy subjects: A randomized c…
2016
Background & aims: Inositols are thought to be mediators of the insulin signalling pathway. We assessed the effects of inositols on glycaemic control in fasting and postprandial states and evaluated lipoprotein profile and LDL particle size in healthy population. Methods: A 12-week double-blind clinical trial was performed with forty healthy subjects administered either an inositol-enriched beverage (IEB) -containing 2.23 g of inositols in 250 ml- or a sucrose-sweetened beverage (SB) twice a day. Anthropometric measurements, fasting glucose levels, insulin and HOMA-IR index, lipoprotein profile and postprandial glucose concentrations (measured using the continuous glucose monitoring system …
Effects of red wine polyphenols and alcohol on glucose metabolism and the lipid profile: a randomized clinical trial.
2013
Summary Background & aims Epidemiological data suggest that moderate red wine consumption reduces cardiovascular mortality and the incidence of diabetes. However, whether these effects are due to ethanol or to non-alcoholic components of red wine still remains unknown. The aim of the present study was to compare the effects of moderate consumption of red wine, dealcoholized red wine, and gin on glucose metabolism and the lipid profile. Methods Sixty-seven men at high cardiovascular risk were randomized in a crossover trial. After a run-in period, all received each of red wine (30 g alcohol/d), the equivalent amount of dealcoholized red wine, and gin (30 g alcohol/d) for 4 week periods, in a…