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Release Devices (release + device)
Selected AbstractsSeason-long mating disruption of citrus leafminer, Phyllocnistis citrella Stainton, with an emulsified wax formulation of pheromoneJOURNAL OF APPLIED ENTOMOLOGY, Issue 6 2010L. L. Stelinski Abstract The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a major worldwide pest of citrus. Larval feeding by this insect facilitates proliferation of citrus bacterial canker, Xanthomonas axonopodis pv. citri. Herein, we describe a season-long disruption trial of P. citrella with a newly developed, emulsified wax dispenser of pheromone (SPLAT-CLMTM). A formulation containing a 3 : 1 blend of (Z,Z,E)-7,11,13-hexadecatrienal:(Z,Z)-7,11-hexadecadienal at a 0.2% loading rate of active ingredient by weight and deployed twice per season (24 weeks total) at 490 g of formulation/ha caused season-long disruption of male moth catch in pheromone traps as well as reduced leaf infestation. Analysis of pheromone release from dispensers by gas chromatography revealed that effective disruption of P. citrella occurred at a deployment rate of 126 ,g of (Z,Z,E)-7,11,13-hexadecatrienal/ha/h. Direct observation of moth behaviour in the field suggested that disruption by this formulation occurred by a non-competitive mechanism. A formulation of the 3 : 1 attractive blend at a 0.02% pheromone loading rate caused only 2,6 weeks of disruption per deployment and did not reduce leaf infestation during mid and end of the season evaluations. A formulation containing 0.2% of (Z,Z)-7,11-hexadecadienal alone and deployed at 490 g/ha caused 6,7 weeks of moth disruption to pheromone traps and did not prevent leaf infestation, while an identical formulation loaded with 0.02% (w/w) of (Z,Z)-7,11-hexadecadienal alone had no effect on P. citrella orientation to pheromone traps. The SPLAT formulation evaluated herein appears to be an excellent release device for (Z,Z,E)-7,11,13-hexadecatrienal given that approximately 100 days of steady release occurred following an initial brief (ca. 7 days) burst of higher release. The advantages of SPLAT as a formulation for P. citrella disruption include low cost of manufacturing, biodegradable and weather resistant characteristics, and flowability allowing machine application. Mating disruption should be an effective alternative to insecticides for management of P. citrella and may reduce the incidence of citrus canker. [source] Active Packaging of Fresh Chicken Breast, with Allyl Isothiocyanate (AITC) in Combination with Modified Atmosphere Packaging (MAP) to Control the Growth of PathogensJOURNAL OF FOOD SCIENCE, Issue 2 2010Joongmin Shin ABSTRACT:,Listeria monocytogenes,and,Salmonella typhimurium,are major bacterial pathogens associated with poultry products. Ally isothiocyanate (AITC), a natural antimicrobial compound, is reportedly effective against these pathogenic organisms. A device was designed for the controlled release of AITC with modified atmosphere packaging (MAP), and then evaluated for its ability to control the growth of,L. monocytogenes,and,S. typhimurium,on raw chicken breast during refrigerated storage. In order to obtain controlled release during the test period, a glass vial was filled with AITC and triglyceride. It was then sealed using high-density polyethylene film. The release of AITC was controlled by the concentration (mole fraction) of AITC in the triglyceride and by the AITC vapor permeability through the film. The fresh chicken samples were inoculated with one or the other of the pathogens at 104 CFU/g, and the packages (with and without AITC-controlled release device) were flushed with ambient air or 30% CO2/70% N2 before sealing, and then stored at 4 °C for up to 21 d. The maximum reduction in MAP plus AITC (compared to MAP alone) was 0.77 log CFU/g for,L.,monocytogenes,and 1.3 log CFU/g for,S.,typhimurium. The color of the chicken breast meat was affected by the concentration of AITC. Overall, a release rate of 0.6 ,g/h of AITC was found to not affect the color, whereas at 1.2 ,g/h of AITC the surface of the chicken was discolored. [source] Protection of lodgepole pines from mass attack by mountain pine beetle, Dendroctonus ponderosae, with nonhost angiosperm volatiles and verbenoneENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2001D.P.W. Huber Abstract A number of angiosperm nonhost volatiles (NHVs) and green leaf volatiles (GLVs) were tested alone and as supplements to the antiaggregation pheromone, verbenone, for their ability to disrupt attack by the mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae), on lodgepole pine, Pinus contorta Dougl. ex Loud. var. latifolia Engel. Preliminary experiments led to a refined NHV blend [benzyl alcohol, guaiacol, benzaldehyde, nonanal, salicylaldehyde, and conophthorin] and a refined GLV blend [(Z)-3-hexen-1-ol and (E)-2-hexen-1-ol]. In a 20-replicate experiment, NHV and GLV groups both singly, and verbenone alone, significantly reduced MPB mass attack on pheromone-baited trees and on trees within 5 m of the pheromone-baited trees. Both blends in combination with verbenone reduced the number of mass attacked, baited trees to three out of 20 compared to 20 out of 20 of the baited controls. Each binary combination was also effective at reducing mass attack. In these experiments, all tested repellents were released from devices stapled to trees at the same point as the pheromone bait, suggesting that the repellency could have been to a point source, rather than to the whole tree. Therefore, in two further experiments bands of release devices were wrapped around the treated trees and the pheromone bait was removed from the treated trees. In one experiment, when the aggregation pheromone bait was suspended between pairs of trees treated with the NHV blend plus GLV blend plus verbenone, only three out of 25 treated pairs had mass attack on at least one member of the pair. In the other 60-replicate experiment, with no pheromone baits present, attack occurred on 13 untreated and 11 banded trees, all in the path of a large advancing infestation. However, the mean attack density on the banded trees was significantly reduced to a level below the 40 attacks m,2 of bark surface required to kill a healthy lodgepole pine. As a result of these experiments, operational trials are recommended. [source] The effect of water on particle size, porosity and the rate of drug release from implanted titania reservoirsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2010Tessy Lopez Abstract The implantation of controlled drug release devices represents a new strategy in the treatment of neurodegenerative disorders. Sol,gel titania implants filled with valproic acid, have been used for this purpose to treat induced epilepsy in rats. The kinetics of the drug release depend on: (a) porosity, (b) chemical interactions between valproic acid and surface hydroxyl groups of titania, (c) particle size, and (d) particle size agglomerates. The concentration of water used in the hydrolysis reaction is an important variable in the degree of porosity, hydroxylation, and structural defects of the nanostructured titanium oxide reservoir. The titanium n -butoxide/water ratio was systematically varied during the sol,gel synthesis, while maintaining the amount of valproic acid constant. Characterization studies were performed using DTA-TGA, FTIR, Raman, TEM, SEM, BET, and in vitro release kinetic measurements. The particle agglomerate size and porosity were found to depend on the amount of water used in the sol,gel reaction. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [source] Mechanistic understanding of degradation in bioerodible polymers for drug deliveryAICHE JOURNAL, Issue 12 2002Domenico Larobina A new model was developed to understand the mechanism of erosion in bioerodible polymers, which is essential to accurately predict drug release and precisely design controlled release devices. This model takes into account the phenomenon of microphase separation observed for polyanhydrides of certain copolymer compositions, and assumes that erosion is dominated by degradation and, thus, in a system with a fast eroding and a slow eroding species, two rate constants,one for each species,essentially control the evolution of the polymer microstructure. Expressions were derived for the fraction of each monomer released, as well as for the porosity in the system. A partition coefficient accounts for thermodynamic partitioning of a drug into the microdomains. The solutions of the model equations were fitted to experimental data on monomer release kinetics from two polyanhydride systems to obtain the erosion rate constants. Drug release kinetics experiments are compared to the model solution for drug release, and the partition coefficient of the drug is obtained from the fits. The comparisons to the data are promising, while pointing out the limitations of the model. The model does not account for oligomer formation prior to monomer release or for the dependence of the rate constants on parameters such as the degree of crystallinity, the local pH, and the polymer molecular weight. [source] Synthesis of thermosensitive guar-based hydrogels with tunable physico-chemical properties by click chemistryJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2010Morgan Tizzotti Abstract Thermosensitive guar-based hydrogels are obtained in water solutions by copper-catalyzed 1,3-dipolar cycloaddition between alkyne-functionalized guars and ,,,-diazido-poly[(ethylene glycol)- co -(propylene glycol)]. Characterization by TGA, HR-MAS 1H NMR, and rheology have shown that hydrogels with tunable physico-chemical properties, such as crosslinking density, viscoelasticity, swelling ratio, and so forth, could be obtained by varying the guar molar mass, the degree of alkyne functionality, the guar/crosslinker weight ratio, and the reaction temperature. Based on swelling measurements, it has been shown that the thermal sensitiveness of guar-based hydrogels is fast, reversible, and intimately related to the weight fraction of the thermosensitive crosslinker in the network. Finally, the monitoring of doxorubicin hydrochloride release has demonstrated the potential of these hydrogels as temperature-dependent drug release devices. The robust, efficient, and orthogonal approach described herein represents a general approach towards the development of well-controlled guar-based hydrogels using ,,,-diazido crosslinkers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2733,2742, 2010 [source] | ||||||||||||||||