Search results for "Kinetic analysis"
showing 10 items of 20 documents
General Kinetic Analysis and Comparison of Molecular Weight Distributions for Various Mechanisms of Activity Exchange in Living Polymerizations
1997
The molecular weight distributions in many living (e.g. anionic, group transfer, cationic, and radical) polymerizations strongly depend on the dynamics of various equilibria between chain ends of d...
Idarubicin-loaded beads for chemoembolisation of hepatocellular carcinoma: results of the IDASPHERE phase I trial
2014
SummaryBackground A phase I dose-escalation trial of transarterial chemoembolisation (TACE) with idarubicin-loaded beads was performed in cirrhotic patients with hepatocellular carcinoma (HCC). Aim To estimate the maximum-tolerated dose (MTD) and to assess safety, efficacy, pharmacokinetics and quality of life. Methods Patients received a single TACE session with injection of 2 mL drug-eluting beads (DEBs; DC Bead 300–500 μm) loaded with idarubicin. The idarubicin dose was escalated according to a modified continuous reassessment method. MTD was defined as the dose level closest to that causing dose-limiting toxicity (DLT) in 20% of patients. Results Twenty-one patients were enrolled, inclu…
Thermal analysis applied to the characterization of degradation in soil of polylactide: II. On the thermal stability and thermal decompositon kinetics
2010
[EN] The disposal stage of polylactide (PLA) was assessed by burying it in active soil following an international standard. Degradation in soil promotes physical and chemical changes in the polylactide properties. The characterization of the extent of degradation underwent by PLA was carried out by using Thermal Analysis techniques. In this paper, studies on the thermal stability and the thermal decomposition kinetics were performed in order to assess the degradation process of a commercial PLA submitted to an accelerated soil burial test by means of multi-linear-non-isothermal thermogravimetric analyses. Results have been correlated to changes in molecular weight, showing the same evolutio…
A kinetic study of the formation of smectic phases in novel liquid crystal ionogens
2013
[EN] A multi-rate non-isothermal kinetic analysis of the isotropic-melt to liquid crystalline phase transition of novel liquid crystalline ionogenic copolymers, LCIs, the 10-(4-methoxyazobenzene-4'-oxy)decyl methacrylate]-co-2-(acrylamido-2-methyl-1-propanesulfonic acid)s, 10-MeOAzB/AMPS, copolymers, has been performed by means of calorimetric experiments. An analytical methodology which includes the study of the phase transition rate parameter, the determination of the activation energies by using Kissinger and Flynn-Wall-Ozawa models, and the study of the phase transition kinetics by the use of the Avrami theory, has been applied. The formation of the mesophases from the isotropic state o…
The role of polaronic states in the enhancement of CO oxidation by single-atom Pt/CeO2
2023
Single Atom Catalysts (SACs) have shown that the miniaturization of the active site implies new phenomena like dynamic charge transfer between isolated metal atoms and the oxide. To obtain direct proof of this character is challenging, as many experimental techniques provide averaged properties or have limitations with poorly conductive materials, leaving kinetic measurements from catalytic testing as the only reliable reference. Here we present an integrated Density Functional Theory-Microkinetic model including ground and metastable states to address the reactivity of Pt1/CeO2 for CO oxidation. Our results agree with experimentally available kinetic data in the literature and show that CO…
The Role of Eucalyptus Species on the Structural and Thermal Performance of Cellulose Nanocrystals (CNCs) Isolated by Acid Hydrolysis
2022
Cellulose nanocrystals (CNCs) are attractive materials due to their renewable nature, high surface-to-volume ratio, crystallinity, biodegradability, anisotropic performance, or available hydroxyl groups. However, their source and obtaining pathway determine their subsequent performance. This work evaluates cellulose nanocrystals (CNCs) obtained from four different eucalyptus species by acid hydrolysis, i.e., E. benthamii, E. globulus, E. smithii, and the hybrid En × Eg. During preparation, CNCs incorporated sulphate groups to their structures, which highlighted dissimilar reactivities, as given by the calculated sulphate index (0.21, 0.97, 0.73 and 0.85, respectively). Although the impact o…
The influence of pH on the stability of antazoline: kinetic analysis
2015
Degradation of the drug antazoline was studied in aqueous solutions by means of pH-rate profiling (pH 0–7.4). The novel approach of Runge–Kutta numerical integration in combination with multi-parameter optimisation was applied to UV-Vis spectral data to determine a valid kinetic model and kinetic parameters of the degradation process. The overall degradation mechanism was found to be dependent on the environmental pH. In the pH range of 3.0–7.4, the formation of the antazoline hydrolysis product (N-(2-aminoethyl)-2-(N-benzylanilino)acetamide) through three different pathways (acidic, non-catalysed, and semi-alkaline hydrolysis) was observed. In highly acidic media (pH 0–2), the degradation …
Thermal and thermo-oxidative stability of reprocessed poly(ethylene terephthalate)
2013
An exhaustive assessment of the behaviour of virgin and mechanically reprocessed poly(ethylene terephthalate) (PET) facing thermal and thermo-oxidative decomposition processes is presented in this work, as an approach for the energetic valorisation of post-consumer PET goods. Multi-rate linear-non-isothermal thermogravimetric (TGA) experiments under inert (Ar) and reactive (O2) conditions were performed to virgin PET and its recyclates in order to simulate the thermal behaviour of the materials facing pyrolysis and combustion processes. The release of gases was monitored by evolved gas analysis of the fumes of the TGA experiment, by in-line Fourier-transform infrared (IR) analysis, with the…
Kinematics and subpopulations' structure definition of blue fox (Alopex lagopus) sperm motility using the ISAS® V1 CASA system.
2013
Contents Over recent years, technological advances have brought innovation in assisted reproduction to the agriculture. Fox species are of great economical interest in some countries, but their semen characteristics have not been studied enough. To advance the knowledge of function of fox spermatozoa, five samples were obtained by masturbation, in the breeding season. Kinetic analysis was performed using ISAS® v1 system. Usual kinematic parameters (VCL, VSL, VAP, LIN, STR, WOB, ALH and BCF) were considered. To establish the standardization for the analysis of samples, the minimum number of cells to analyse and the minimum number of fields to capture were defined. In the second step, the pre…
Pharmacokinetic analysis of the interaction between dicoumarol and tolbutamide in man
1976
The effect of repeated administration of tolbutamide on the elimination and anticoagulant action of a single oral dose of dicoumarol 600 mg was studied in four healthy male subjects using a crossover design. In all subjects the plasma concentration of dicoumarol in the postabsorptive phase was lower during concomitant tolbutamide treatment. However, the subjects differed with respect to the elimination kinetics of dicoumarol and the effect of tolbutamide on some of the measured pharmacokinetic paramaters. In two subjects dicoumarol was eliminated by apparent first-order kinetics. Tolbutamide led to a pronounced increase in the elimination rate and a shift in the plasma concentration-respons…