Effect of Relative Humidity on the Oxidative Stability of Microencapsulated Sea Buckthorn Seed Oil

ABSTRACT: The effect of relative humidity (RH) (20 °C: RH 11%, 54%) on oxidative stability microencapsulated sea buckthorn seed oil was studied using bulk oil as a reference. Microcapsules were prepared by spray-drying using maltodextrin-gum arabic (MD/GA) and corn starch sodium octenyl succinate derivate (HiCap) as the wall materials. The influence of the physical state of the wall material was also evaluated. Under dry conditions, the microencapsulated oils were most stable, but the oxidation of the bulk oil was accelerated. At 20 °C and at RH 11%, the peroxide value of the bulk oil exceeded 20 meq/kg within 1 wk. Microencapsulation prolonged the shelf-life of the oil from 1 wk to 2 mo at 20 °C, when the encapsulating matrix was in glassy state. In conditions in which the HiCap matrix was in a rubbery state (RH 54%, 20 °C), the oxidation proceeded very quickly, reaching a peroxide value of 20 meq/kg just after 1 wk. Caking and collapse of the microcapsule powder were observed in the rubbery state. At accelerated conditions (50 °C: RH 11%, 30%, 45%), the oxidation was noticeably fast, not only in the bulk oil but also in the MD/GA matrix, even in the glassy state. The behavior in the HiCap matrix was more complex as the amount of peroxides started to decrease in time. This was assigned to the structural collapse in HiCap microcapsules. The behavior of the microencapsulated oils under accelerated conditions did not correlate with their behavior at 20 °C.     

Thermodynamic properties of malonic, succinic, and glutaric acids: evaporation rates and saturation vapor pressures

This work provides thermodynamic data, in particular, liquid-state saturation vapor pressures of three common slightly water soluble secondary organic aerosol components, namely, malonic, succinic, and glutaric acids. A modified tandem differential mobility analyzer system was used to measure evaporation rates of nanometer sized aqueous malonic, succinic, and glutaric acid droplets at relative humidities and temperatures relevant in the lower troposphere. Liquid phase saturation vapor pressures and other thermodynamic properties were derived from the measurements using a binary condensation model. The obtained expressions for liquid phase saturation vapor pressures compare well with extrapolated literature data. The importance of the choice of method for calculating activity coefficients is discussed.     

Synthesis of nitrogen-functionalized polyolefins with metallocene/methylaluminoxane catalysts

Summary Thirteen differently substituted long-chain amide- and amine-functional alkenes were synthesised and used as comonomers in zirconocene/methylaluminoxane-catalysed copolymerizations with ethylene and propylene. Characterization of the prepared copolymers showed the formation of functionalized copolymers with isolated comonomer units. The incorporation level of the comonomers ranged from 0.24 to 1.3 mol % with ethylene and from 0.04 to 0.96 mol % with propylene. The molar masses of the copolymers were lower than those of the corresponding homopolymers. End group analysis of the copolymers by NMR suggested that the dominant chain termination mechanism was chain transfer to aluminium. Received: 8 December 2000/Accepted: 12 February 2001     

Great differences in the ways of implementing the new EIA Directive – the offerings of the EIALAW 2018 conference

On the 23 March 2018, the most recent developments of the environmental impact assessment (EIA) law were examined by experts in Helsinki. The main theme of the conference was the comparison of the implementation experiences of various countries concerning the reformed EU EIA Directive. The European EIA debate was reflected against experiences in Canada. This paper examines the key points of the conference presentations and the lessons of the event.     

Strong coupling between surface plasmon polaritons and Sulforhodamine 101 dye

We demonstrate a strong coupling between surface plasmon polaritons and Sulforhodamine 101 dye molecules. Dispersion curves for surface plasmon polaritons on samples with a thin layer of silver covered with Sulforhodamine 101 molecules embedded in SU-8 polymer are obtained experimentally by reflectometry measurements and compared to the dispersion of samples without molecules. Clear Rabi splittings, with energies up to 360 and 190 meV, are observed at the positions of the dye absorption maxima. The split energies are dependent on the number of Sulforhodamine 101 molecules involved in the coupling process. Transfer matrix and coupled oscillator methods are used to model the studied multilayer structures with a great agreement with the experiments. Detection of the scattered radiation after the propagation provides another way to obtain the dispersion relation of the surface plasmon polaritons and, thus, provides insight into dynamics of the surface plasmon polariton/dye interaction, beyond the refrectometry measurements.PACS: 42.50.Hz, 33.80.-b, 78.67.-n     

Plane wave propagation in a uniaxial bianisotropic medium with an application to a polarization transformer

Uniaxial bianisotropic medium is a generalization of the well-studied bi-isotropic and chiral media. It is obtained, for example, when microscopic helices with parallel axes are positioned in a host dielectric in random locations. Plane wave propagation in such a medium is studied and a simple solution for the dispersion equation and for the eigenwaves are found. As a numerical example, polarization properties of a transverse wave propagating in a uniaxial bianisotropic medium is considered. The results give a simple possibility to construct a polarization transformer with a transversely uniaxial chiral medium for changing the polarization of a propagating plane wave.     

Pulmonary function in horses with recurrent airway obstruction after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively

OBJECTIVE: To determine changes in clinical signs of disease and response to pulmonary function testing in horses with recurrent airway obstruction (heaves) after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively. ANIMALS: 6 horses with inducible and reversible heaves. PROCEDURE: Episodes of heaves were induced by exposure (challenge) to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone dipropionate, parenterally administered dexamethasone, aerosolized propellant [control]), and respiratory frequency and subjective assessment of respiratory effect were determined twice daily. Maximal change in pleural pressure (delta-Pplmax), pulmonary resistance (RL), and dynamic compliance (Cdyn) was determined on days 0, 7, 10, 14, and 21. RESULTS: The RL and delta Pplmax were increased, and Cdyn was decreased in all horses in response to natural challenge. Beclomethasone reduced RL on day 10, reduced delta Pplmax on days 14 and 21 and increased Cdyn on day 14. Dexamethasone reduced RL and delta Pplmax on days 10, 14, and 21 and increased Cdyn on days 10 and 14. Respiratory effort (subjective assessment) improved after 2 and 3 days of beclomethasone and dexamethasone administration but rebounded to pretreatment values 1 and 3 days after discontinuation of drugs. CONCLUSIONS: Pulmonary function testing responses and clinical signs of airway obstruction were improved by administration of beclomethasone. The magnitude of response to aerosolized beclomethasone generally was less marked than the response to parenterally administered dexamethasone. Higher or more frequent dosing of aerosolized beclomethasone may be necessary to achieve the anti-inflammatory response to parenterally administered dexamethasone.