Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2000-09-22
2002-05-07
Warden, Sr., Robert J. (Department: 1744)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S132000, C604S145000, C604S131000, C422S001000
Reexamination Certificate
active
06383165
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to fluid delivery applications and more specifically to a system for achieving a controlled low emission rate for small volumes of chemical agents for pest and insect management. The emission of chemical agents such as insecticides, pesticides, pheromones, etc. to control pests, frequently requires controlled and accurate rates of delivery, if specific results, such as kill rate, mating interruption, aggregation prevention, etc., have to be achieved, effectively. Whenever multi-component chemical agent blends are required, it is extremely difficult to achieve and maintain the desired emission rates, using existing delivery devices, or emitters.
The examples recited below from published experiments, illustrate the need for release control and show that available devices do not satisfy this need.
In Japan, the tea tortrix is a serious pest, on tea plants. Pest control can be achieved by mating disruption, using Z-11-TDA (Z-11 tetradecenylacetate) as the mating interruption pheromone. In these experiments, it was possible to show the following agent activity.
Release rate of Z-11-TDA
Mating ratio
(mg/day/hectare
%
1300
68
2000
45
3500
20
Mating disruption is proportional to pheromone release rate. Therefore, the emitter, preset for a specific rate, should sustain it, since mating is not appreciably prevented below rates of 2000 mg/day/ha. Furthermore, since different dose rates are needed in different areas, the emitter should be flexible enough to accommodate different rates.
In another controlled test, small moths (Prays oleae), lured by PBX, were trapped in five successive time periods by four different doses, ranging from 0.1 to 20.0 mg. The dose-response relationship, reported below, points to a maximum catch, at 1.0 mg, which is twice that for any other doses.
Mean catches with lure doses of
0.1 mg
1.0 mg
5.0 mg
Time sequence
Year 1981
Oct 04
18.0
56.8
24.3
Oct 09
31.3
70.8
24.3
Oct 14
39.3
68.0
31.3
Oct 18
43.7
43.2
40.0
Oct 21
6.7
17.8
13.3
TOTAL
139.0
260.6
152.9
Obviously, the effectiveness of the trap is strongly affected by the ability to maintain a 1.0 mg dose.
In Western Europe, four species of tortridid moths infest fruit orchards. All species use dodec-8-en-1-o1 acetate (8-12-26 Ac) as major component, available as (Z) or (E) isomers. However, 100% attractivity towards the binary mixture is achieved in the following manner:
5% of (E) isomer in the blend attracts G(Grapholita) funebrana
10% of (E) isomer in the blend attracts G-molesta
25% of (E) isomer in the blend attracts G-janinthana
90% of (E) isomer in the blend attracts G-iobarzewski
In this case, the integrity of the species is maintained by differentiating blend compositions. Therefore, if both isomers are not emitted at the appropriate rate, multiple species may be attracted.
In British Columbia (1991), verbenone was tested as an anti-aggregation pheromone for mountain pine beetle. At an emission rate of 3.8 mg/day, from a concentrated source, the pheromone completely inhibited response to an attractant blend consisting of myrcene, exo-brevicomin and trans-verbenol. When verbenone was released from beads on the forest floor, effectiveness was reduced by 50%. When exposed to sunlight, 50% of verbenone was converted to the inactive chrysanthenone, within 75 to 100 minutes. Rapid isomerization probably reduced verbenone concentration to below biologically active levels. This illustration points to the specific need of point sources and to the danger of exposing the pheromone to sunlight.
Similarly, in another antiaggregation experiment, an optimum dosage of verbenone was determined to reduce infestation of mountain pine beetle in lodgepole pines in Central Idaho.
The results of the previous experiments are used as a way to illustrate the critical nature of pheromone concentration, the narrow concentration ranges for effectiveness, the need to emit from concentrated, or point, sources, and the specificity of the emission rate. Point sources are only symptomatic of the need to create a repeatable concentration gradient to which the insects are responding.
Pheromone dispensers can be grouped in two general classes: passive devices, which are based on natural forces (evaporation, diffusion, etc.) and active devices which require man-made energy sources (batteries, springs, etc.)
Passive Devices
Plastic Laminate Dispensers contain pheromone trapped between layers of plastic films. The emission rate is proportional to the inverse of square root of time, such that Rate=a t
−½
where (a) is a characteristic of film properties and geometry. Devices of this type display a high initial emission rate progressively decreasing to zero. This behavior is characteristic of first order kinetics, i.e. the rate is concentration-dependent. Since the coefficient (a) is also dependent on the properties of the pheromone, it is 1) difficult to control the rate, and 2) in the case of multicomponent blends it is not possible to control the concentration ratios of individual components. Hollow fibers are used as capillaries from which the pheromone diffuses through the vapor-air volume, considered the rate-controlling step. Therefore, the rate should be predictable. However, liquid retention within walls and fiber cross-channels result in a release rate between order zero and one commercial success is further hampered by the financial investment in the equipment required to process the fiber bundles.
Microcapsules consist of packaging chemicals in a microgranular form with stabilizing agents. The 1-1000 microns diameter capsule contains the pheromone which is therefore protected from the environment, i.e. light and oxygen. Again, since the active ingredient concentration within the capsule changes with time, the emission rate is first order, i.e. time-dependent.
Other dispensers have also been developed and used. They include polyethylene tubes, rubber septa, polyvinyl chloride rods or pellets, cigarette filters, polyethylene vial caps, dental roll, etc.
In summary, none of the existing and currently-in-use dispensers can achieve the “ideal” zero-order delivery, or the sustained release of multiple pheromones at concentration ratios required for an effective use of generally expensive chemical agents.
It will be the primary object of the present invention to show that “ideal” control release is achievable.
Active Devices
Timed release spray dispensers have been used for mating interruption of the blackheaded fireworm. A battery-powered timing mechanism operating a valve is used to spray the sex pheromone solution at preset time intervals. Spray dispensers are nearly zero-order release devices. However, the intermittent delivery results in “spurt” emission, thereby creating a discontinuous release.
The object of this invention will be to demonstrate “continuous” emission.
Although the previous examples specifically describe pheromones, the present invention is also suitable for liquids such as fragrances, insect formulations, sanitizers, disinfectants, repellents, aromatherapuetic formulations, or any other such liquid requiring delivery in a controlled manner.
The following summarizes certain desired dispenser features and attributes and emitter characteristics, albeit not necessarily achievable simultaneously.
Compatibility with most pheromones
Compatibility with a variety of solvents, diluents, additives, ranging from water to functional chemicals to hydrocarbons
Compatible with multicomponent blends
Maintaining the relative concentration ratios of all components in solution
Long term (6 months) storage of the pheromone in the dispenser without adverse effects (evaporation, phase separation, chemical changes, etc.)
Protection from light, UV and oxygen
Release at “quasi” steady state (zero-order)
Release of multicomponent blends without affecting individual component rates
Readily changeable delivery rate, i.e. use of the dispenser for a variety of different rates, with minor changes.
Long term delivery capability
Ease of filling and sealing the reservoir
Eas
Maget Henri J. R.
Rosati Robert J.
Conley Sean E.
Logan II Garles C.
Warden, Sr. Robert J.
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