Cross Reference to Related Applications

[01] This application claims priority to U.S. Provisional Application No. 63/156,102, filed March 3, 2021; and U.S. Provisional Application No. 63/315,978, filed March 2, 2022. These applications are incorporated herein by reference in their entireties.

Field of the Invention

[02] This invention relates generally to aqueous liquid herbicidal compositions, and more particularly, but not by way of limitation to, an improved high-load aqueous liquid herbicidal composition containing one or more active ingredients from a phosphinic acid group, and methods for their preparation, transportation and end-use.

Background of the Invention

[03] Glufosinate is a broad-spectrum herbicide that is commonly used to control invasive weeds in agricultural production. Glufosinate is commercially available, and its herbicidal activity has been well documented (e g., by F. Schwerdtle et al. Z. Pflanzenkr. Pflanzenschutz, 1981, Sonderheft IX, pp. 431-440). Glufosinate, (also referred to as phosphinothricin or glufosinate ammonium, with a common name of DL-4- [hydroxyl(methyl)phosphinoyl]-DL-homoalaninate) is a naturally occurring broad- spectrum herbicide produced by several species of streptomyces soil bacteria. Glufosinate is a non-selective, contact herbicide, with some systemic action. The compound irreversibly inhibits glutamine synthetase, an enzyme necessary to produce glutamine and for ammonia detoxification, giving it antibacterial, antifungal, and herbicidal properties. The application of glufosinate to plants leads to reduced glutamine and elevated ammonia levels in tissues, halting photosynthesis and resulting in plant death.

[04] Various compositions of and methods for making and using glufosinate have been described by documents such asU.S. Pat. No. 10,781,465 to Green, U.S. Pat. No. 9,999,223 to Sievernich, U.S. Pat. No. 9,834,802 to Green, U.S. Pat. No. 8,895,470 to Yerkes, U.S.

Pat. No. 6,544,930 to Wright, and U.S. Pat. No. RE37,866 to Wright. The aforementioned patents are incorporated herein in their entirety by reference. Known compositions and methods of making and using glufosinate however have physical and chemical stability issues that can lead to decreased efficacy of increased storage and transportation costs. There is, therefore, a need for an improved composition of glufosinate, with increased physical and chemical stability, which increases or retains the biological efficacy on target pests, as well as a need for methods for preparation, transportation, and end use of such a composition. It is to these and other objectives that the present invention is directed.

Summary of the Invention

[05] In one embodiment, the present invention is a composition directed to a water- soluble phosphinic acid-based pesticide. In another aspect, the present invention includes methods for making a novel highly concentrated and stable phosphinic compound and correlated salts formulation with a concentration between about 450 and 650 grams per liter or as a weight percentage between 36% w/w and 53% w/w of phosphinic compound. The preferable phosphonic compound active ingredients are glufosinate, L-glufosinate, and an enantiomeric ratio of both, including potential salts derivates from the neutralization of the acid form and premixes of both the acids and salts forms. The pesticides can be soluble, slightly soluble, or soluble after a neutralization in a basic compound. The soluble pesticides result in a highly concentrated and stable phosphinic acid and correlated salts formulation when dissolved in water. In one embodiment L-glufosinate or glufosinate ammonium is dissolved in water and a co-solvent is added. The co-solvent is used to prevent an increase in viscosity and to prevent crystallization at lower temperatures. The mixture may be agitated to promote mixing and to prevent bridging within the solution. The solution may also be neutralized with a basic compound. In addition, an antifoaming agent may be added to prevent foaming in the formulation and a surfactant may be added to the solution to add desirable properties to the solution for application. The resulting phosphinic acid formulation has improved stability, greater application convenience, optimized biological effectiveness, better safety in manufacturing, and decreased transportation, storage, and disposal costs.

Brief Description of the Drawings

[06] FIG. 1 shows data tables for phosphinic compound formulations with various cosolvents.

[07] FIG. 2 shows data tables for phosphinic compound formulations with various surfactants.

[08] FIGS. 3a-3o show data tables describing the efficacy results of phosphonic compound formulations with L-glufosinate as the active ingredient.

[09] FIGS. 4a-4ii show data tables with additional trial data describing the efficacy results of phosphonic compound formulations with L-glufosinate as the active ingredient.

[10] FIGS. 5a-5j show data tables for standard phosphonic compound formulations.

[11] FIGS. 6a-6f show data tables and samples describing the results of solubility tests of phosphonic compound formulations with L-glufosinate and glufosinate as the active ingredient.

[12] FIGS. 7a-7n show the diagrams of surface tension test results of phosphonic compound formulations with L-glufosinate as the active ingredient combined with surfactants. [13] FIGS. 8a-8b show data tables describing the solubility results of phosphonic compound formulations.

[14] FIGS. 9a-9d show solubility and surfactant data tables corresponding to FIGS. 7a- 7n.

Written Description

[15] Compositions and methods for making a novel highly concentrated and stable phosphinic acid and correlated salts formulation are provided herein. In a first embodiment of the invention, a formulation is derived from water-soluble pesticide compositions. The preferable pesticides to form the formulation are glufosinate, L-glufosinate, and an enantiomeric ratio of both, including potential salts derivates from the neutralization of the

acid form and the premixes of both the acids and salts forms. The pesticides can be soluble, slightly soluble, or soluble after a neutralization in a basic compound. The soluble pesticides result in a highly concentrated and stable phosphinic acid and correlated salts formulation when dissolved in water. In the present embodiment the phosphinic compound may be deployed in solution as salts, such as glufosinate ammonium salt at a concentration between 450 grams per liter and 650 grams per liter or as a weight percentage between 36% w/w and 53% w/w. Concentrations expressed as percent by weight herein relate to parts by weight of compound, salt, solid, or acid equivalent per 100 parts by weight of the total formulation. Other salts compatible with phosphinic acid will be apparent from the prior art. To form the formulation a phosphinic compound is dissolved in a water. The solution is then agitated until dissolution of the phosphonic compound. Agitation of the solution prevents bridging within the solution and to promotes a homogenous mixture. A co-solvent is then added to the solution. In addition to the co-solvent, antifoam and a surfactant are added to the solution to allow for easier application of the formulation. The resulting formulation is an aqueous liquid suitable for spray applications.

[16] In an embodiment of the invention the phosphonic compound and water are combined to produce a solution. The phosphonic compound is added in amounts sufficient to produce a formulation with a phosphonic compound concentration between 450 and 650 grams per liter or as a weight percentage between 36% w/w and 53% w/w. The phosphonic compound may be glufosinate, L-glufosinate, or an enantiomeric ratio of both compounds. After the phosphonic compound is added, the solution is agitated to dissolve the phosphonic compound in the water solvent. After the dissolution of the phosphonic compound, a co-solvent is added to the solution to prevent an increase of viscosity and crystallization at low temperatures. In one embodiment a co-solvent of propylene glycol is added to the solution. In other embodiments different co-solvents may be added to the solution, such as propylene glycol n-propyl ether, propylene glycol methyl ether acetate, 2-(2-Ethoxyethoxy)ethanol, Rhodiasolv RPDE, 2-(2-Butoxyethoxy)ethanol, Augeo Film, polyethylene glycol 400, tripropylene glycol mono methyl ether, ethylene glycol, Proprionitrile, Rhodiasolv Polarclean, Rhodiasolv LI TEC 2V, diisodecyl adipate, tris (2- ethylhexyl)trimellitate, tributyl acetyl citrate, Bis(2-ethylhexyl) terephthalate, Zendex DB 300 Bis(2-ethylhexyl) adipate, propylene glycol, propylene glycol mono methyl ether, N,N-dimethylacetamide, dimethyl sulfoxide, benzoate esters, diisodecyl adipate, tributyl citrate, isobutylalcohol, N-butylpyrrolidone, and acetonitrile.

[17] In formulations with propylene glycol, the co-solvent may be added in concentrations up to about 150 grams per liter or as a weight percentage up to 12% w/w. In other embodiments or in formulations with other co-solvents, the concentration range may be broader or limited to narrower ranges. In such embodiments one or more co solvents may be added in amounts sufficient to produce stable formulations of aqueous liquid suitable for spray applications. The concentration ranges of co-solvent and other components in the formulation may be adjusted such that the stability of the formulation remains greater than or equal to the stability of formulations with lower weight percentages of phosphonic compound. The stability of the formulation may be measured as a function of the density and viscosity of the formulation. The concentration range may vary depending on the co-solvent used. It is necessary to maintain a range of concentrations to ensure that a formulation with acceptable properties is achieved. For instance, in formulations where the concentration of propylene glycol is lower than about 50 grams per liter or 4% w/w the viscosity of the formulation will increase at lower temperatures. In addition to increased viscosity, gelling and crystallization of the formulation may occur with concentrations of propylene glycol lower than about 50 grams per liter or 4% w/w in the formulation. At concentrations of propylene glycol of about 150 or 12% w/w grams per liter or greater, the phosphonic compound formulation may become unstable and the active ingredient may not solubilize. It will be understood that in formulations with other cosolvents, different concentration ranges for the co-solvent may be used to achieve a formulation with viscosities suitable for typical application, transportation, and storage purposes. These variations may be apparent from the example formulations described below and in the figures. For the example, for the co-solvents Tributyl acetylcitrate, Propylene glycol mono methyl ether, N,N-Dimethylacetamide, Dimethyl Sulfoxide, Diisodecyl Adipate, Tributyl citrate, Isobutylalcohol, and Acetonitrile, limpid and stable formulations are achievable using concentrations between about 50 and 100 grams per liter or 4% and 12% w/w. It will be understood however that other concentrations may be used to achieve stable formulations with workable viscosities. Additional data regarding solutions prepared using these co-solvents is available in FIG 1.

[18] The data in FIG. 1 was recorded to determine compatibility of various co-solvents within the phosphonic compound formulation. The data was recorded on a standard phosphonic compound formulation with either about 50 grams per liter (4% w/w) or about 100 grams per liter (8% w/w) of co-solvent. The standard phosphonic compound formulation consisted of about 463 grams per liter (38% w/w) of a water solvent, about 120 grams per liter (10% w/w) of a surfactant, alkylpolyglucoside as Surfom CS 8902, and about 586 grams per liter (48% w/w) of a phosphonic compound, 95.5% glufosinate. The standard phosphonic compound formulation was prepared according to the methods outlined above and measurements were taken for various co-solvents to determine the aspect, density, viscosity and pH of the formulation. As shown in FIG. 1 various co solvents produce workable formulations with between about 50 grams per liter (4% w/w) and 100 grams per liter (8% w/w) of co-solvent.

[19] In the present embodiment a solution is prepared by adding phosphonic compound to a solvent such as water. After the solution of solvent and phosphinic compound is prepared, a co-solvent may be added to the solution. In one embodiment a phosphinic compound or a salt thereof is dissolved in the solvent at a concentration between about 450 and 650 grams per liter or as a weight percentage between 36% w/w and 53% w/w. It will be understood by those of skill in the art that normal variations in measurements may account for some variation in the upper and lower limits of the concentration ranges measured for each component of the formulation. In a typical formulation the variation may account for at least a variation of +/- 0.5% from the stated range limits. In other embodiments the concentration of phosphinic compound dissolved in water may be less than 450 grams per liter or greater than 650 grams per liter or as a weight percentage between 36% w/w and 53% w/w depending on the specific phosphonic compound used in the formulation. In one embodiment, it was observed that at -2°C and -8°C, 600 grams per liter (49% w/w) of glufosinate ammonium was the maximum achievable concentration for that specific the phosphonic compound at the specified temperatures. In other embodiments, glufosinate ammonium was added to the solution at concentrations of 500 (41% w/w), 560 (46% w/w), and 650 grams per liter (53% w/w) while retaining efficacy in the formulation. Once the phosphinic compound is added to the solution, the mixture is then sufficiently agitated to promote mixing and to prevent bridging within the solution. A co-solvent may then be added to the solution. As discussed above, in the present embodiment the co-solvent is used to prevent an increase in viscosity at higher concentrations of phosphinic compound.

[20] A surfactant is also added to the solution to add desirable properties for application. A surfactant may be added to the solution at about 50 grams per liter up to about 250 grams per liter or as a weight percentage at about 4% w/w to up to about 20% w/w. In other embodiments one or more surfactants are added in amounts, sufficient to produce stable formulations of aqueous liquid suitable for spray applications. In the present embodiments, surfactants such as an alkyl-polyglucoside surfactant system, or alcohol ethoxylated surfactants including isotridecylic and isodecylic may be mixed with the solution. In other embodiments different surfactants such as Lauryl Alcohol 7 EO, Sorbitan Monooleate 20 EO, Lauramine Oxide (and) Myristamine Oxide, Betaine, Alkylpolyglucoside, Isotridecyl Alcohol Ethoxylated, Lauryl Alcohol 6 EO, Cetyl Oleyl Alcohol Ethoxylate 5 EO, Isodecyl Alcohol Ethoxylate 6 EO, Alkyl Polyglucoside 50% content CMC 87.1, Alkyl Polyglucoside 60% content, Alkyl Polyglucoside 50% content CMC 61.2, Alkyl Polyglucoside 50% content CMC 67.2, Alkylamidopropyl Betaine, Alkylglucamide, Polyglycerol ester, Mixture of Methylated Seed Oil with Polyglycerol Ester, Secondary Alcohol Ethoxylates, Seed Oil Alkoxylate, Polyacrylate, Polycarboxylate 40% content, Polycarboxylate 45% content, Disodium Coco-Glucoside Sulfosuccinate, SorbitanMonooleate 80 EO, Isodecyl Alcohol Ethoxylate 6 EO, Sodium Laureth-2 Sulfate, and Block Copolymer 40 EO may be used. Clear and particle-free formulations are formed with the following surfactants of those listed above, ethoxylated alcohol, betaines, EO/PO copolymers, alkyl glucamide, alkyl polyacrylate, sulfosuccinate, alkyl polyglucoside (APG). Enough surfactant is added to achieve surface tension values for formulations which are less than 35 dn/cm. Of the surfactants listed above, Polyacrylates and EO/PO copolymers show the highest surface tension values, above 40 dn/cm. Still in other embodiments different suitable surfactants may be used. Additional data regarding solutions prepared using these surfactants is available in FIG 2.

[21] The data in FIG. 2 was recorded to determine compatibility of various surfactants within the phosphonic compound formulation. The data was recorded on a standard phosphonic compound formulation with the surfactant concentration being between about 50 grams per liter and about 250 grams per liter or as a weight percentage at about 4% w/w to up to about 20% w/w in the trials in FIG 2. The standard phosphonic compound formulation consisted of about 463 grams per liter (38% w/w) of a water solvent, about 50 grams per liter (4% w/w) of a co-solvent, alkylpolyglucoside as Surfom CS 8902, and about 586 grams per liter (48% w/w) of a phosphonic compound, 95.5% glufosinate. The standard phosphonic compound formulation was prepared according to the methods outlined above and measurements were taken for various surfactants to determine the aspect, average contact angle, average surface tension, density, viscosity, and pH of the formulation. As shown in FIG. 2 various surfactants produced workable formulations.

[22] The surfactant may be added after the phosphonic compound salt of pesticide acid is dissolved in a solvent such as water. Additional mixing or agitation may be applied to the solution to fully incorporate the surfactant into the solution. The added surfactant may add wetting agent properties that provide better efficacy and allow for easier spray application of the pesticide. These added properties allow the pesticide to be more easily applied to target plants, improving application convenience of the formulation over other L-glufosinate and glufosinate formulations currently available. To achieve sufficient wetting agent properties, concentrations of surfactant can be used which are lower than concentrations in common commercial formulations. The minor surfactant load in the formulation can provide sufficient wetting agent properties but avoid the foam promotion that is present in some common commercial formulations. This minor load surfactant ratio protects efficacy of the formulation. In some embodiments an antifoam agent may also be added to reduce foaming. In addition to the added surfactant properties benefits, the phosphonic compound formulations also show reduced viscosity over tradition formulation and surfactant systems. The reduced viscosity allows for better handling of the formulation, particularly in lower temperatures.

[23] In some embodiments the solution may also be neutralized with a basic compound. The resulting phosphinic compound formulation has improved stability, improved application convenience, optimized biological effectiveness, more safety in manufacturing, and better logistics savings which include transportation, storage, and disposal costs. The solubility in water of the phosphonic compound L-glufosinate at this concentration is believed not to be recorded in prior art. Similarly, aqueous solutions of the phosphonic compound L-glufosinate and salts thereof at concentrations up to 650 grams per liter (53% w/w) are believed not to have been specifically disclosed, thus any unusual or unpredicted properties of such solutions have not been publicly known. These stable highly concentrated aqueous formulations can hold larger amounts of phosphonic compounds than formulations which are currently available. This higher concentration also allows formulations to be transported or stored more efficiently. [24] In the phosphonic compound formulations, the acid form generally shows weaker biological activity or no biological activity compared to the salt of pesticide acid. To improve the efficacy and stability of the formulation in the acid form, the formulation can be chemically neutralized. Bases such as ammonia, potassium hydroxide (KOH) or amine bases such as triethanolamine (TEA), monoisopropanolamine (MIPA), diethanolamine (DEA), and dimethylamine (DMA), or various other sufficient bases could provide potential neutralization for the formulation. Proper neutralization helps to improve the efficacy and stability of the selected active ingredient. In formulations with multiple components, such as those with a salt and acid in a single formulation, neutralization can provide a broad spectrum of control. This broad spectmm of control can increase the effectiveness of the formulation and thereby increase the cost effectiveness of the formulation.

[25] The phosphonic compound formulation described above is a water base formulation. Since the salt of pesticide acid is dissolved in water, the solution can later be further diluted with additional water for application. Thus, solution is infinitely dilutable, allowing the end user to tune the concentration of the salt of pesticide acid to the desired concentration using water. The formulation has improved stability over current L- glufosinate and glufosinate ammonium formulations. The added stability will allow more variation in storage, transportation, and end use. After preparation the formulation will remain stable in storage over a broad range of as indicated above and in the figures.

[26] The following examples and results are provided for illustrative purposes only and are not intended to limit the scope of the present invention. The examples will permit better understanding of the invention and perception of its advantages and certain variations of execution.

[27] Turning now to FIGS. 3a-3o, and FIGS. 4a-4ii, shown therein are data tables describing the efficacy test results of an embodiment of the phosphonic compound formulations described above. FIGS 4a-4ii provide additional detail on the efficacy test shown in FIGS. 3a-3o. The results in the tables in FIGS. 3a-3o and 4a-4ii present efficacy data of the phosphonic compound formulation with L-glufosinate as the active ingredient with a concentration between 450 grams per liter and 650 grams per liter or as a weight percentage between 36% w/w and 53% w/w. ALB 2051 and ALB 2052, the phosphonic compound formulations with L-glufosinate as the active ingredient, were prepared according to the methods described above with component concentrations within the ranges described above. The formulations were then applied to a variety of common pests. A total of eleven pests were tested, including white clover, palmer amaranth, tall waterhemp, sicklepod, velvetleaf, prickly sida, pitted morningglory, hogweed, wild mustard, large crabgrass, and annual blue grass. It will be understood that other pest may respond similarly to the novel formulation and that these were selected as examples of the novel formulation’s efficacy. The results of the efficacy trials were compared to results for standard glufosinate compound formulations such as Albaugh’s Surmise and BASF’s Liberty.

[28] The efficacy of each phosphonic compound formulation was tested over a twenty- eight-day period against each pest. Efficacy readings were taken against a control on the first, third, seventh, tenth, fourteenth, and twenty-eighth day after the application of the formulation. The efficacy of the ALB 2051 and ALB 2052 formulations were each tested at three different rates, with ALB 2051 being tested at 4 fl oz/a, 8 fl oz/a, and 10.75 fl oz/a and ALB 2052 being tested at 4.5 fl oz/a, 9 fl oz/a, and 12 fl oz/a. The other formulations in the trial, Albaugh’s Surmise and BASF’s Liberty, were also tested at three different rates, with Albaugh’s Surmise and BASF’s Liberty being testing at 16 fl oz/a, 32 fl oz/a, and 43 fl oz/a. As shown in FIGs 3a-3o, and 4a-4ii the phosphonic formulations ALB 2051 and ALB 2052 the phosphonic formulations performed as well or better than existing formulations at lower flow rates.

[29] Turning now to FIGS. 5a-5j, shown therein are data tables for standard phosphonic compound formulations. The standard phosphonic formulation tested in FIGS. 5 contained a water solvent with a concentration of 463.61 grams per liter (38% w/w), propylene glycol as a co-solvent at a concentration of 50 grams per liter (4% w/w), alkylpolyglucoside as product Surfom CS 8902 as a surfactant at a concentration of 120 grams per liter (10% w/w), and the phosphonic compound glufosinate 95.5% as the active ingredient at a concentration of 586.39 grams per liter (48% w/w). These standard formulations had a load of 500 SL. The data in FIGS. 5a-5j was recorded to measure the stability through various properties of the standard phosphonic formulation such as the density, pH, miscibility, and persistent foam, as well as the changes in these properties over time and temperature ranges. The standard formulation was prepared according to the methods described above for phosphonic compound formulations. As shown in FIG. 5a-5j, the formulations were stable and retained their glufosinate content when tested up to 14 days after preparation. The formulations were tested across a range of temperatures between -8 degrees Celsius and 54 degrees Celsius and produced workable formulations in this range. [30] Turning now to FIGS. 6a-6f shown therein are data tables and samples describing the results of solubility tests of phosphonic compound formulations with L- glufosinate and glufosinate as the active ingredient. Each formulation tested included a combination of L-glufosinate and glufosinate, water, propylene glycol, and antifoaming agent, and a surfactant. In FIGS. 6a, 6c, and 6e the trials tested L-glufosinate ammonium and glufosinate ammonium mixed in ratios of 50/50, 75/25, and 90/10 to achieve a combined concentration of 560 grams/liter of the glufosinate mixture. Three trials were conducted for each combination of L-glufosinate ammonium and glufosinate ammonium, testing each formulation with a different surfactant combination which included Surfom CS 8902 (Alkylpolyglucoside (APG)), Synergen GA (alkylglucamide), Genagen CAB (alkyl betaine), and SLES 270 (sodium lauryl ether sulfate). The resulting formulations and solubility are shown in FIGS. 6b, 6d, and 6f.

[31] Turning now to FIGS. 7a-7n shown therein are the diagrams of surface tension test results of phosphonic compound formulations with L-glufosinate as the active ingredient combined with surfactants. The diagrams and tables show the change in surface tension over time for LDF 01-LDF 12 and water, as well as the parameters for the trials. In FIGS. 9a-9d the corresponding solubility and surfactants for LDF 01-LDF 12 as referenced in FIGS. 7a-7n are shown. The tested surfactants included Lauryl Alcohol 7 EO, Sorbitan Monooleate 20 EO, Lauramine Oxide (and) Myristamine Oxide, Betaine, Alkylpolyglucoside, Alkyl Polyglucoside 50% content CMC 87.1, Alkyl Polyglucoside 60% content, Alkylamidopropyl Betaine, Alkylglucamide, Polyacrylate, Disodium Coco- Glucoside Sulfosuccinate, and Block Copolymer 40 EO. Corresponding with parameters from FIG. 5a-5j, the formulations were stable and retained their glufosinate content when tested at 7 days and 14 days after preparation. The formulations were tested at -8 degrees Celsius and 54 degrees Celsius and produced miscible formulations.

[32] Turning now to FIGS. 8a-8b shown therein are data tables describing the solubility results of phosphonic compound formulations. L-glufosinate at 560 grams per liter was tested. The L-glufosinate was derived from various combinations of potassium salt and ammonium salt L-glufosinate. The combined salt formulations were tested with surfactant combinations Surfom CS 8902 + Genagen CAB, Surfom CS 8902 + Alkopon NS, and Surfom CS 8902 + Synergen GA and antifreezing agents of 5%, 7% and 10% w/v Propylene glycol, and 10% w/v Dowanol PM. The 90% ammonium salt with 10% potassium salt L-glufosinate formulations were tested again with parameters from FIG. 5a-5j . The resulting formulations of Surfom CS 8902 + Genagen CAB, and Surfom CS 8902 + Synergen GA were stable and retained their glufosinate content when tested 14 days after preparation for all three temperatures tested. The formulations were tested at -8 degrees Celsius and 54 degrees Celsius and room temperature.

[33] While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth hereinabove but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains. Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. Certain ranges are presented herein with numerical values being preceded by the term "about." The term "about" is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrecited number may be a number, which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number.