A process for preserving baked goods takes advantage of the discovery that a form of modified whey characterized by a calcium content of at least 3%, protein content of from 10 to 20%, and a phospholipid content of at least 2%, has high antimicrobial activity, particularly, antimycotic activity. Baked flour-containing foods are formulated to contain sufficient amounts of the modified whey to provide a desired antimicrobial activity, e.g., from about 2 to about 10% of the modified whey will improve the stability of baked goods having moisture contents as high as 50%.

The invention relates to baked food products improved with a modified whey of novel composition to control microbial growth, and a process for improving the storage stability of baked goods by supplementing the dough or batter used to prepare them with the modified whey.
Baked goods tend to be susceptible to microbial growth. Mold growth is a severe problem, especially in moist products, such as bread, cake, donuts and moist cookies. Preservatives can be added to some foods, but generally add expense and are perceived as chemical adulterants by many consumersxe2x80x94they provide no nutritional improvement to a food substrate and are of no functional importance other than preservation.
While a number of efforts have been made to address these interrelated problems, the art is in need of effective solutions.
In developed nations, the incentive for food preservation is largely one of economics. In less-developed societies, life itself depends on the ability of man to avoid waste of food. There is a need for a preservation technology that is fully compatible with moist baked goods processing and, preferably, will have some other advantage such as to aid in reducing the amount of other ingredients.
Many food additives have been available as preservatives. For example, in U.S. Pat. No. 3,202,514, Burgess, et al., describe the use of sugars and other soluble food ingredients to provide shelf stability in intermediate moisture foods. This technology has been adapted to a wide variety of foods, including meats, vegetables, soups and stews, baked goods and others, typically having moisture contents of from about 15 to 50%. However, the use of anitmycotics is still considered necessary.
In U.S. Pat. No. 3,753,734, Kaplow, et al., describe the preparation of shelf stable pancake and waffle products. Because these products have such high moistures and water activities, the use of polyhydric alcohols constitute the principal source of water soluble solids. In addition, antimycotics such as sorbates are preferably employed.
In U.S. Pat. No. 4,154,863, Kahn, et al., describe a variety of intermediate moisture, ready-to-use, frozen foods. They assert that microbiologically stable flour based batters can be prepared which remain soft and ready for use at freezer temperatures and which can be maintained at room temperature and refrigerator temperature for an extended period of time, by controlling their sugar/fat content. The batters are of intermediate-moisture content and have sufficient sugar solutes to provide a bacteriostatic effect.
Many other food ingredients have been added for nutritional advantage or as cost-saving substitutions for other ingredients, but have not been recognized for preservation. For example, whey, as it is conventionally available, has been used as an ingredient for human and animal foods. Historically, it was used as a waste product and for animal feed products. More recently, economically attractive uses for whey have been foundxe2x80x94not only for its own inherent nutrition, but also as a replacement for eggs, flour or fat. See for example, G. Ranhotra, xe2x80x9cUse Of Whey And Whey Products In Baked Goodsxe2x80x9d, Technical Bulletin, Volume XVII, Issue 11, November 1995. Several modified forms of whey have been developed, principally by fractionating to obtain various fractions valuable for specific uses based on the concentration of nutritional or functional characteristics.
Conventionally-available whey products as described in the above reference have low protein, fat and ash contents. With typical, high concentrations of lactose, commercial sweet whey is often suggested for use in low amounts (2 to 6% of flour) in yeast-leavened bakery products to improve crust color, tenderize crumb and improve color. Baked goods containing it, however, are still highly-susceptible to mold growth.
In U.S. Pat. No. 4,301,179, Schmidt discloses a bread dough for standard white bread which incorporates whey and pea flour. Pea flour in a relatively small amount is said to act to substantially reduce dough mixing time, to increase fermentation aroma, and to obtain improved taste in the bread, and yet not destroy the well recognized character of the baked product as standard white bread. The disclosure also relates to a milk substitute for use in bread that consists essentially of a dry blend of pea flour and whey. Bread dough having the pea-whey milk substitute is said to be characterized by reduced mixing and fermentation times, but also the resulting baked bread has been found to have a superior crust color and crumb structure.
In U.S. Pat. No. 4,421,777, Chung describes a process for preparing a chocolate flavored cake comprising mixing together and baking cake ingredients, and adding to the ingredients of about 3% to about 15% on a flour basis of (1) a defined whey protein-containing composition in combination with (2) an amount of sodium bicarbonate sufficient to elevate the pH of the cake crumb to a pH within the range of about 7.5 to about 9.
In U.S. Pat. No. 5,320,859, Namdari describe a high protein dough mix for a leavened bakery product, consisting essentially of, by weight, in unflavored form, a blend of up to 20% water, 10-80% of a protein containing material selected from the group consisting of soy products, gluten, milk products, whey products, egg products and nuts, 10-80% of a sweetener, up to 40% of a vegetable shortening, up to 50% flour, and up to 8% of a leavening agent. The dough mix may be baked and served as a cookie, a muffin, a cake, a brownie, or a snack bar.
In U.S. Pat. No. 4,501,757, Smith, et al., describe yeast quickener and dough conditioner compositions having the ability to reduce raising and baking times and improving shelf life of the baked product. Particularly superior characteristics are reportedly obtained by adding an activating amount of fenugreek and a rancidity inhibiting amount of rosemary to a combination of (1) whey solids, (2) lecithin, (3) ascorbic acid, along with fillers and flavoring agents such as starch, salt, dried honey and silica gel or a silicate salt.
In distinction to conventional whey, a variety of modified whey products have been proposed for a number of food supplements.
As noted above, and in U.S. Pat. No. 3,791,283, to Moreno, et al., whey can be concentrated to improve its protein content to make it more suitable for use as a protein supplement. In the noted patent disclosure, the protein is also specially treated to make it more stable in an acid beverage. However, the microbiological stability of the product is not apparently improved.
Indeed, in U.S. Pat. No. 4,081,555 there are described whey concentrates stabilized against putrefying action using a combination of downward pH adjustment (to 2.5-4.2) and a preservative agent. The best results are obtained with benzoates and/or sorbates as the preservative agent.
In U.S. Pat. No. 5,262,187, Hahn discloses a low-fat dry mix, ready-to-use batter and baked compositions which are composed of a sweetened, cereal-grain ingredient base with a fat mimetic system of polydextrose, cellulosic material, non-fat milk solid or substitute, emulsifier, modified food starch, and a mixture of xanthan gum and guar or locust bean gum, preferably with lecithin and whey protein concentrate. The baked composition is reported as moist, tender, crumbly with good mouthfeel but contains, one-third fewer calories than a similar full-fatted composition.
In U.S. Pat. No. 4,109,025, Lauck discloses partially replacing the shortening requirement of leavened baked goods with a whey protein concentrate wherein the protein is substantially undenatured and non-oxidized. Protein enriched, lower fat content products such as biscuits are prepared.
In U.S. Pat. No. 4,214,010, Corbett discloses replacing up to 75% of the whole egg requirement of a custard using from about 40% to about 60% of a whey protein concentrate containing from about 0.5% to about 5% carboxymethylcellulose and from about 60% to about 40% of a lactylated shortening. They report substantially no change in the food product containing the substitution which provides an economic advantage.
In U.S. Pat. No. 3,941,895, Ash, et al., describe a selected demineralized and partially delactosed whey is used as a substitute for nonfat dry milk in various food compositions. The selected whey has a predetermined ash to protein ratio of 0.01 to 0.3. Also, the selected whey can be combined with a modified starch to provide a satisfactory replacement for the nonfat dry milk constituent in baked goods.
In U.S. Pat. No. 4,118,514, Hoseney, et al., disclose a low-cost substitute for nonfat dry milk (NFDM) solids as a functional equivalent of NFDM in yeast-leavened doughs used in bread making or the like. It is said to provide desirable organoleptic properties such as loaf volume, crumb quality and crust color. The substitute comprises a component such as an ammonium salt which serves as a source of ammonium ion in the dough, and a quantity of deproteinized whey; these components are characterized as synergistic for maintaining or enhancing loaf volumes while giving good crust color and crumb quality, notwithstanding the fact that deproteinized whey alone has deleterious effect when used alone in doughs. In preferred forms, the substitute is said to serve as both a functional and at least a partial nutritional replacement for NFDM in yeast-leavened doughs, but is lower in cost and can be used without difficulty in both batch and continuous bread making processes.
There remains a need for a process for preserving baked goods and to the resulting baked goods.
It is an object of the invention to provide a process for preserving baked goods.
It is another object of the invention to provide preserved baked goods.
It is another object of the invention to provide formulations and processes for baked goods that eliminate the need for special preservatives.
It is a further object of the invention to provide baked goods preservatived with economical food ingredients that are not perceived as chemical adulterants.
It is yet another object of the invention to provide formulations for baked goods with food additives that can replace the functionality of more expensive ingredients and, in addition, have a preservative function.
It is also an object of the invention to provide foods preserved with additives that replace other, more-costly food ingredients.
These and other objects are achieved by the present invention, which provides baked products preserved with modified whey and a process for preparing baked products with improved stability by utilizing modified whey in their preparation, the modified whey being characterized by a calcium content of at least 3%, protein content of from 12 to 18%, and a phospholipid content of at least 2%.
Many of the preferred aspects of the invention are described below.
The following description will illustrate the preparation of preferred preserved foods and processes according to the invention, including those highlighted above. The processing will be described in terms of the procedures effective for the materials employed in the various formulations. It will be understood by those skilled in the art, however, that some will have to be modified to accommodate them where necessary.
Basic to all of the embodiments of the invention is a xe2x80x9cmodified wheyxe2x80x9d, which is defined as a whey fraction characterized by a calcium content of at least 3%, protein content of from 12 to 55%, and a phospholipid content of at least 2%. The calcium content is in highly soluble form and is homogeneously dispersed therein, as can be obtained by being codried with the protein, fat and sugar components separated to form the whey fraction. Calcium in this form is distinguished from calcium added as a salt that is simply mixed in dry form with whey. Preferred forms of modified whey are further characterized as conforming to the following analysis, based on a 100-gram sample.
Typical calcium to phosphorous ratios are within the range of from about 2:1 to about 10:1, e.g., about 5:2. Similarly, typical calcium to protein ratios are within the range of from about 1:4 to about 4:5, e.g., about 1:3. And, typical calcium to fat (essentially as phospholipid) ratios of from about 3:1 to abut 10:1, e.g., about 4:1.
Products meeting these specifications can be prepared from whey by fractionation and drying to obtain the noted composition. They are commercially available, for example, under the trademark VERSAPRO (various grades, including A, B, D, F, M, N, S) from Davisco Foods International, Inc., LeSueur, MN.
Example 1, below reports the results of a study to challenge several substrates (both using and not using the invention) with mold cultures to determine their susceptibility to mold growth, and Example 2 illustrates the use of modified whey as an antimycotic in baking cake donuts.
Among the food products that can be improved according to the invention are baked goods, other flour-based foods such as pasta and noodles, prepared entrees, meat extenders or extended meat products, and other foods, e.g., snack foods of the type prepared by extruder expansion and gun puffing. An advantage of the invention is that the use of modified whey can enable reducing or eliminating egg yolks in some formulations and can have advantages in nutrition and leavening, color and flavor in baked products.
Baked goods and doughs (the term xe2x80x9cdoughxe2x80x9d as used herein is also intended to include xe2x80x9cbattersxe2x80x9d) for their preparation, can be formulated as usual to contain modified whey and at least flour and water in reasonable amounts to form the desired dough for baking. Among baked goods are included cakes, cookies, crackers, breads, pan cakes, biscuits and other baked products of less-distinct grouping.
The term flour includes flour milled from starchy plants, flour substitutes, and starches. Flours and starches useful in this invention include those derived from wheat, corn, rice, waxy maize, rye, barley, peas, various beans, potato, arrow root, sorghum and waxy sorghum. Starches can be raw, gelatinized, chemically modified or physically treated. Generally about from 15 to 80% flour is adequate, depending on the type of baked goods desired. More typical amounts will be from about 20 to 60%. The amount of water added will depend on the nature of the dough or batter desired for a particular type of product. The water will be sufficient to hydrate the ingredients sufficiently to form the batter or dough and sufficient to gelatinize the starch in the flour.
Most doughs will also contain salt, sugar, fat or oil and leavening, such as yeast or chemical leavening such as baking powder. Some doughs made for extrusion contain no leavening and are expanded by extrusion. Baked goods can employ as much of the modified whey as can be tolerated by the particular product in terms of texture, taste and appearance. Typical concentrations of modified whey will range from about 2 to about 25%, preferably from 3 to 10%, of the modified whey based on the weight of product. Using at least 10% on this basis will generally have a significant impact on deterring mold growth in baked products, yet permit yeast growth in batters and doughs.
The type of fat can be varied widely between saturated and unsaturated depending on the type of cake and texture desired. An unsaturated fat will often provide superior flow and nutritional properties.
Fats high in unsaturation are typically liquid at room temperature and often referred to as oils, include safflower oil, corn oil, soybean oil, cottonseed oil and sunflower oilxe2x80x94unsaturated fats typically have iodine values of about at least 50 which include partially hydrogenated fats, and the more highly unsaturated fats with an iodine value above about 100. These fats are often recommended for dietary purposes, particularly for those with a high plasma cholesterol level which is associated with atherosclerosis.
The saturated fats include the hydrogenated oil products of coconut, cottonseed, corn, soybean, peanut, olive, etc. Fats having a melting point of 90xc2x0-94xc2x0 F. are preferred, i.e., the melting point should be below body temperature.
The term xe2x80x9csugarxe2x80x9d is to be understood as meaning any of a number of useful saccharide materials. Included in the list of useful sugars are the mono-saccharides, di-saccharides and polysaccharides and their degradation products; e.g., pentoses, including aldopentoses, methylpentoses, keptopentoses, like xylose and arabinose; a deoxyaldose like rhamnose, hexoses and reducing saccharides such as aldo hexoses like glucose, galactose and mannose; the ketohexoses, like fructose and sorbose; disaccharides, like lactose and maltose; non-reducing disaccharides such as a sucrose and other polysaccharides such as dextrin and raffinose; and hydrolyzed starches which contain as their constituents oligosaccharides.
The products of this invention are characterized by its substantial resistance to bacterial decomposition, but may serve as a host for yeasts and mold, the foods of this invention may have an antimycotic agent incorporated at a sufficient level to prevent the growth of such organisms. It is an advantage of the invention that the amount required for this purpose will be less than otherwise. Sorbate salts such as potassium sorbate as well as sorbic acid can be used either separately or in combination. Propylene glycol which may be used alone or with other humectants like sorbitol to impart a further degree of product softness or tenderness can also serve as an anti-mycotic. Other anti-mycotic agents will be apparent to those skilled in the art. The amount of anti-mycotic agent added is selected so as to produce the desired results and will constitute a minor proportion of the product, about 0.1% or higher, depending on the particular anti-mycotic and the particular product composition, although even lower levels in the order of 50 p.p.m. can be employed in the case of some anti-mycotics as pimarcin. Potassium sorbate in a water solution can be sprayed into the surface of the food or the food can be dipped in this solution; other anti-mycotics lend themselves to such surface application as esters of the parabens (para-hydroxy benzoate) such as propyl and methyl parabens (methyl para-hydroxy benzoate). Cellophane and other enwrapments for the food can be spray coated with a sorbic acid solution but impregnation or dusting with sorbic acid or potassium sorbate is preferred. Anti-mycotics which can generally be used are benzoic acid, sodium benzoates, proprionic acid, sodium and calcium proprionate, sorbic acid, potassium and calcium sorbate, propylene glycol, diethyl pyrocarbonate, and menadione sodium bisulfite (vitamin K).
Other ingredients known to those skilled in the art may also be employed to impart their characteristic effects to the compositions of the present invention. Typical of such ingredients are flavoring agents, colorants, vitamins, minerals, and the like. Suitable flavoring agents can be employed to impart vanilla, cream, chocolate, coffee, maple, spice, mint, butter, caramel, fruit and other flavors. Additionally, the use of certain polyols such as sorbitol and mannitol can be employed to modify mouthteel. Furthermore, other additives such as phosphates and the like may be employed for their known functions. Several types of ingredients used are described below.
Protein in the form of whole egg, egg whites, egg yolks, or various concentrates and isolates are useful to improve the nutritional qualities of the product and to facilitate and maintain structure. Protein also aids in emulsification and contributes to flavor. Bland protein concentrates with a wide range of fiber content, bland soy flour, milk powder and food proteins are all useful, generally in concentrations about from 0-10%, preferably about from 0.3-3%. Alternatively, use can be made of a protein such as sodium or calcium caseinate, or as its substitute a protein hydrolysate in a minor amount.
Emulsifiers are often employed in baked goods for emulsification, dough conditioning and other utilities. A wide variety of emulsifiers may be employed in amounts on the same order as in the prior art oil-in-water emulsions for example, about from 0.1-5%, preferably about from 0.2-1.5%. Among those suitable are: hydroxylated lecithin; mono, di, or polyglycerides of fatty acids, such as monostearin and monopaimitin; polyoxyethylene ethers of fatty esters of polyhydric alcohols, such as the polyoxyethylene ethers of sorbitan monostearate (polysorbate 60) or the polyoxyethylene ethers of sorbitan distearate; fatty esters of polyhydric alcohols such as sorbitan monostearate; mono-and di-esters of glycols such as propylene glycol monostearate, and propylene glycol monopalmitate, succinoylated monoglycerides; and the esters of carboxylic acids such as lactic, citric, and tartaric acids with the mono-and diglycerides of fatty acids such as glycerol lacto paimitate and glycerol lacto stearate. The fatty acids employed in the preparation of the emulsifiers include those derived from beef, tallow, and coconut, cotton seed, palm, peanut, soybean and marine oils. Many blends of emulsifiers are commercially used and readily available in accordance with known techniques. For example, it may be desirable to provide a controlled hydrophil-lipophil balance (HLB) as with a lipophilic emulsifier such as glyceryl monostearate or sorbitan monostearate with a hydrophilic material such as polysorbate 60.
The compositions of the present invention can also include one or more stabilizers or hydrophilic colloids to improve processing and product properties as known in the art. These stabilizers are natural, i.e. vegetable, or synthetic gums and may be, for example, carrageenin, guar gum, alginate, xanthan gum and the like or methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxypropyl methlycellulose (Methocel 65 HG), micro-crystalline cellulose and the like, and mixtures thereof. Typically, a gum or combination of gums is employed with a sugar, e.g. dextrose, carrier. The amount of these stabilizers can be varied widely in accordance with the amounts required in prior art compositions, generally about from 0-2%, preferably about from 0.1-0.5%.
Many types of salts are used in the compositions of this invention for flavoring, including common salt (sodium chloride), sodium or potassium phosphates, citrates, chlorides, and the like, in amounts about from 0-5%, but preferably about from 0.1-1%.
Antioxidants such as butylated hydroxytoluene, butylated hydroxyanisole and tertiary butyl hydroquinone may be used in minor amounts (i.e. as Tenox 22 antioxidant).
Food grade acidulants such as phosphoric, tartaric, malic, citric, fumaric, hydrochloric and the like edible food acids are suitable to impart tartness, control pH or serve as a preservative.
The preferred products of the invention will have Aw (water activity) values of from about 0.60 to about 0.95. The term xe2x80x9cwater activityxe2x80x9d is well understood in the art to be a measure of free water in a food and is typically measured by measuring the equilibrium relative humidity in the head space of a container holding a test food which has been given time to equilibrate. Under some circumstances, some mold and yeast can grow at Aw values less than 0.60, but typically dry baked goods having moistures of 2-3% can be stored at 65% relative humidity without spoilage. On the other hand, foods with Aw values above about 0.85 are difficult to stabilize without significant levels of chemical additives.
There are commercially available devices for measuring the water activity of formulations. For example, a formulation may be placed in a container until equilibration is reached and then the humidity in the container measuredxe2x80x94based on standard tables the water activity is then determined. For example, electric hygrometers are devices commonly used to measure water activity. These devices contain sensors impregnated with salts such as lithium chloride or potassium chloride. Water is adsorbed on the sensor and causes a change in electrical resistance which is measured by a wheatstone bridge. Reference curves based on solutions of known humidity are used to relate the electrical readings to water activity.
The bafters and doughs are prepared in the typical fashion for the type of product desired. The flour and water are typically mixed with the intensity needed to either develop gluten, emulsify fats or simply mix without eitherxe2x80x94as the case may be. Once prepared, the dough or batter is permitted to rise in the case of yeast-leavened goods or directly baked in the case of chemically-leavened goods. The baking times, as the mixing, are well within the skill of the art. Baking by oven, stove top, extruder or other suitable cooking device are all included.


Oleophobic and hydrophobic filters for filter venting applications are made by forming a fluorosulfone coating on the surface of a filtration substrate. The filters have high water penetration pressures and high air permeabilities. The coatings are formed by grafting a fluorosulfone oligomer to a polymeric substrate.

The present invention relates to filtration media having both hydrophobic (water repellent) and oleophobic (oil repellent) properties. The properties are produced by forming a fluorosulfone oligomer coating on a substrate such as a hydrophobic or hydrophilic membrane or other filtration medium. The invention also relates to methods of preparing such filtration media.
Hydrophobic filters are used in filtration of gases, in venting filters, and as gas vents. These hydrophobic filters allow gases and vapors to pass through the filter while liquid water is repelled by the filter.
Polytetrafluoroethylene (PTFE) has been the most commonly used material in filters for gas venting. PTFE is chemically and biologically inert, has high stability, and is hydrophobic. PTFE filters therefore allow gases to be selectively vented while being impervious to liquid water.
Hydrophobic membranes are used as filters in healthcare and related industries, for example, as vent filters for intravenous (IV) fluids and other medical devices. In the healthcare industry, the membrane is sterilized before use. PTFE membranes can be sterilized for these health-related applications with steam or by chemical sterilization without losing integrity.
Treating PTFE membranes with steam can cause pore blockage due to condensation of oil from the machinery used to generate the steam. The resulting loss of air permeability reduces the membrane""s ability to serve as an air vent. Although chemical sterilization minimizes exposure of the membrane to oil, chemical sterilization uses toxic chemicals and can generate byproducts which cause waste disposal problems. Ionizing radiation has also been used for sterilization of materials used in medical and biological devices. PTFE may become unstable when exposed to ionizing radiation. Irradiated PTFE membranes have greatly reduced mechanical strength and cannot be used in applications where they are subjected to even moderate pressures.
Perhaps the two biggest drawbacks to PTFE as a filter for venting gases are the high cost and the low air permeability of PTFE membranes. PTFE membranes are formed by extruding and stretching PTFE. Both the PTFE raw material and the processing to form the PTFE membrane are expensive. Furthermore, the extruding and stretching processes used to form PTFE membranes create a membrane which has relatively low air permeability.
The oleophobicity of PTFE can be improved by impregnating or coextruding the PTFE with siloxanes (for example, U.S. Pat. No. 4,764,560), fluorinated urethane (U.S. Pat. No. 5,286,279), or perfluoro-2,2-dimethyl-1,3-dioxole (U.S. Pat. No. 5,116,650). Although the oil resistance of the PTFE is improved, the treated PTFE membranes are expensive, and air permeability remains fairly low.
As a result, efforts have been made to identify alternative substrates which are less expensive and have higher air permeability than PTFE and which can be modified to be hydrophobic and oleophobic.
Coating filtration substrates allows one to retain the desirable bulk properties of the substrate while only altering the surface and interfacial properties of the substrate. Coating substrates to increase their hydrophobic and oleophobic properties has not been very practical, because the coatings can reduce permeability. Furthermore, many of the coating materials are expensive.
Scarmoutzos (U.S. Pat. No. 5,217,802) modified the surface of substrates made of nylon, polyvinylidene difluoride (PVDF), and cellulose by treating the substrate with a fluorinated acrylate monomer. The substrate was sandwiched between two sheets of polyethylene, and the monomer was polymerized by exposing to ultraviolet light. The resulting composite filters had hydrophobic and oleophobic surfaces. The air permeability of the filters decreases with time.
Moya (U.S. Pat. No. 5,554,414) formed composite filters from polyethersulfone and PVDF membranes with a method similar to that of Scarmoutzos. The resulting filters did not wet with water or hexane. The disadvantage of the Moya filters is that air permeability of the treated filters was lower than the untreated substrates, and the fluorinated monomer is expensive.
Sugiyama et al. (U.S. Pat. No. 5,462,586) treated nylon fabric and PTFE membranes with solutions containing two different preformed fluoropolymers. The treated filters were resistant to water and oils. The durability of filters coated with preformed polymers is often less than that for filters where the coating is formed by polymerizing a monomer on the surface of the substrate, however.
Kenigsberg et al. (U.S. Pat. No. 5,156,780) treated a variety of membranes and fabrics with solutions of fluoroacrylate monomers and formed coatings on the substrate by polymerizing the monomer. The coating conferred oil and water repellency onto the substrate. However, the airflow through the treated membrane was reduced, compared to the untreated membrane.
Hydrophobic media suitable for garments have been made by extruding mixtures of polypropylene or PTFE and the fluorochemical oxazolidinone as disclosed in U.S. Pat. No. 5,260,360. The media made by extrusion tend to have relatively low air permeability.
In copending U.S. application Ser. No. 09/323,709 filed Jun. 1, 1999, now U.S. Pat. No. 6,355,081 issued Mar. 12, 2002 (incorporated herein by reference in its entirety), oleophobic and hydrophobic filters are prepared by forming a polydimethylsiloxane coating on a polymeric substrate by polymerizing vinyl terminated siloxane with a crosslinker such as hydrosilicon in the presence of a catalyst.
There is a need for an oleophobic and hydrophobic filter which is inexpensive and has high air permeability. Specifically, there is a need for a coating for filter medium substrates that makes the substrate oleophobic and hydrophobic, and also a need for a more cost-effective process of making oleophobic filters.
In a first embodiment of the present invention, an oleophobic filter is provided including a substrate and a coating, the substrate including a polymer and the coating including a fluorosulfone oligomer capable of being covalently bonded to the polymer, wherein the substrate is rendered oleophobic by grafting the fluorosulfone oligomer to the substrate.
In various aspects of the first embodiment, the polymer includes a polysulfone, for example, a polyalkylsulfone, a polyethersulfone, and a polyarylsulfone. The polymer may also include a polyvinylidene fluoride, a polyethylene, poly(tetrafluoroethylene), a poly(tetrafluoroethylene-co-ethylene), a polyamide, a polyacrylate, a polymethacrylate, a polyester, a polypropylene, a nylon, or a polyurethane.
In another aspect of the first embodiment, the substrate includes a porous membrane. The porous membrane may include an isotropic membrane or anisotropic membrane, such as an asymmetric membrane. If the substrate is an asymmetric membrane, the asymmetric membrane may have a supporting structure, a first porous face and a second porous face, each porous face having pore diameters, wherein an asymmetry between the pore diameters of the first porous face and the second porous face is at least about 2:1, at least about 5:1, or at least about 10:1. The supporting structure may also include an isotropic region adjacent the second porous face, the isotropic region having substantially constant pore size, the supporting structure further including an asymmetric region adjacent the isotropic region. The asymmetric region may extend through at least about 50% of the supporting structure but not more than about 85% of the supporting structure. The average diameter of the pores of the second porous face may be between about 0.01 xcexcm and about 50 xcexcm, between about 0.01 xcexcm and about 10 xcexcm, or may be less than about 0.01 xcexcm.
In a further aspect of the first embodiment, the polymeric substrate includes a material including a nonwoven material, a woven material, or a melt blown material.
In another aspect of the first embodiment, the fluorosulfone oligomer includes a polyfluorosulfone acrylate.
In a further aspect of the first embodiment, the oleophobic filter further includes a support, wherein the substrate is bonded to the support. The support may include a fabric. The support may include a polysulfone, a polyethylene, a poly(tetrafluoroethylene), a poly(tetrafluoroethylene-co-ethylene), a polyamide, a polyacrylate, a polymethacrylate, a polyester, a polypropylene, a nylon, or a polyurethane.
In another aspect of the first embodiment, the fluorosulfone oligomer has a structure of formula CnF2n+1SO2N(CH2CH2)CH2CH2OCOxe2x80x94(CH2xe2x80x94CH2)mxe2x80x94CHxe2x95x90CH2, wherein n is an integer from about 5 to about 20, and wherein m is an integer from about 2 to about 10.
In a second embodiment of the present invention, a method of producing an oleophobic filter is provided, the method including providing a polymeric substrate; contacting the substrate with a grafting formulation including a fluorosulfone oligomer; grafting the fluorosulfone oligomer to the substrate; and recovering an oleophobic filter.
In an aspect of the second embodiment, the method further includes providing a support and bonding the substrate to the support.
In a further aspect of the second embodiment, the method further includes providing a support; and bonding the polymeric substrate to the support, wherein the substrate is bonded to the support prior to or after contacting the substrate with the grafting formulation.
In another aspect of the second embodiment, the grafting formulation includes a solvent for the fluorosulfone oligomer. The solvent may include a non-polar solvent or a polar solvent, such as isopropyl alcohol, water, or a mixture of isopropyl alcohol and water.
In a further aspect of the second embodiment, the grafting formulation includes between about 0.05 and about 40 wt. %, between about 0.1 and about 10 wt. %, between about 0.5 and about 5 wt. %, or between about 1 and about 2 wt. % fluorosulfone oligomer.
In another aspect of the second embodiment, the grafting step includes exposing the coated substrate to ultraviolet radiation.
In a further aspect of the second embodiment, the method may further include rinsing the oleophobic filter in a rinsing liquid. The rinsing liquid may include water, isopropyl alcohol, or a mixture of isopropyl alcohol and water.
In another aspect of the second embodiment, the method further includes drying the oleophobic filter at an elevated temperature, wherein the drying step is conducted after the rinsing step.
In a third embodiment of the present invention, a medical device is provided, the device comprising an oleophobic filter, the oleophobic filter comprising a substrate and a coating, the substrate comprising a polymer and the coating comprising a fluorosulfone oligomer capable of being covalently bonded to the polymer, wherein the substrate is rendered oleophobic by grafting the fluorosulfone oligomer to the substrate.
In one aspect of the third embodiment, the oleophobic filter includes an intravenous fluid vent filter.
In a fourth embodiment of the present invention, a method of venting an intravenous fluid is provided, the method comprising the steps of providing an intravenous fluid; providing a receptacle, the receptacle containing the intravenous fluid, the receptacle having a vent, the vent having an oleophobic filter including a substrate and a coating, the substrate comprising a polymer and the coating including a fluorosulfone oligomer capable of being covalently bonded to the polymer, wherein the substrate is rendered oleophobic by grafting the fluorosulfone oligomer to the substrate; and venting a fluid through the oleophobic filter.
In an aspect of the fourth embodiment, the method further includes the step of steam sterilizing the oleophobic filter.
In another aspect of the fourth embodiment, the method further includes the step of sterilizing the oleophobic filter using an ionizing radiation.
The following description and examples illustrate a preferred embodiment of the present invention in detail. Those of skill in the art will recognize that there are numerous variations and modifications of this invention that are encompassed by its scope. Accordingly, the description of a preferred embodiment should not be deemed to limit the scope of the present invention.
The present invention provides hydrophobic and oleophobic filters that have high gas permeabilities and that repel water and other liquids. The invention also includes methods of preparing such filters.
The filter medium substrate is treated with a coating material including a crosslinked fluorosulfone-containing oligomer, which coats the surface of the substrate. Coating the substrate with a material including crosslinked fluorosulfone imparts permanent oleophobicity and hydrophobicity to the filter. The treated filters have high permeabilities for airflow and reject liquid water, as evidenced by high water penetration pressures. The filters are useful, for example, as air filters or vent filters for intravenous (IV) or other medical devices. The critical surface tension for spreading (xcex3c), which is defined as the wettability of a solid surface by noting the lowest surface tension a liquid can have and still exhibit a contact angle (xcex8) greater than zero degrees on that solid, is dramatically reduced for a substrate after treatment according to the method of the invention.
Introduction
Crosslinking is a process wherein a low molecular weight active group, such as an oligomer, is covalently bonded to a parent polymer (for example, a polysulfone or PVDF) so as to modify the surface of the polymer. In one embodiment of such a chemical grafting process, a polymeric substrate is immersed in a solution containing one or more oleophobic fluorosulfone oligomers and polymerization initiators, then post-treated with UV radiation to induce grafting of the fluorosulfone oligomer to the polymeric substrate. In this way, permanent oleophobic groups may be covalently bonded to a polymeric substrate.
The Polymeric Substrate
The membrane or other substrate of the filtration media of preferred embodiments may be prepared from any suitable polymer capable of being grafted with the fluorosulfone oligomer. The polymer may be a homopolymer, copolymer, terpolymer, or more complex polymer. A single polymer or combination of two or more polymers may be preferred. The polymer may be subjected to a pretreatment, for example, sulfonation or grafting prior to forming a membrane casting dope, or may be subjected to a post-treatment, for example grafting or crosslinking, after a membrane is cast or a substrate is formed. There is no particular molecular weight range limitation for useful polymers.
In a particularly preferred embodiment, the polymer is a sulfone polymer, such as polysulfone, polyethersulfone (PES), or polyarylsulfone. Other suitable polymers include fluorinated polymers such as polyvinylidene fluoride (PVDF), polyolefins including polyethylene and polypropylene, polytetrafluoroethylene (PTFE or Teflon(trademark)), poly(tetrafluoroethylene-co-ethylene) (ECTFE or Halar(trademark)), acrylic copolymers, polyamides or nylons, polyesters, polyurethanes, polycarbonates, polystyrenes, polyethylene-polyvinyl chloride, polyacrylonitrile, cellulose, and mixtures or combinations thereof.
The substrates that may be coated may be in any suitable shape or form. If the substrate is a membrane, suitable forms include, but are not limited to, sheet and hollow fiber cast polymer membranes. Suitable membranes further include both those membranes that are cast from a single polymer solution or dope, generally referred to as xe2x80x9cintegralxe2x80x9d membranes, as well as non-integral or composite membranes that are cast from more than one polymer solution or dope to form a layered or composite membrane. Composite membranes may also be assembled from two or more fully formed membranes after casting, for example, by lamination or other suitable methods. Suitable composite membranes are discussed further in copending U.S. patent application Ser. No. 09/694,120 filed on Oct. 20, 2000 and entitled xe2x80x9cLAMINATES OF ASYMMETRIC MEMBRANES,xe2x80x9d which is incorporated herein by reference in its entirety. Polymeric substrates other than membranes are also suitable for grafting with fluorosulfone oligomer according to preferred embodiments. Non-limiting examples of other suitable substrates include hollow fiber media, melt blown or other nonwoven media, woven media, extruded media, and sedimented media. Suitable melt blown substrates include, but are not limited to, polyester, polypropylene or ECTFE, and are commercially available from U.S. Filter/Filterite Division, Timonium, Md.
The filtration media of preferred embodiments may be composites, such as, for example, composites having different layers of any of the foregoing media, composites having multiple layers of the same medium, or composites having layers of the same medium, but of different pore sizes, porosities, geometries, orientations, and the like.
The substrates that are suitable for coating in accordance with the present invention may include membranes having a symmetric or asymmetric pore structure. The term xe2x80x9casymmetricxe2x80x9d as used herein relates to a membrane possessing a pore size gradient. That is, asymmetric membranes possess their smallest or finest pores in or adjacent to one surface of the membrane, generally referred to as the xe2x80x9cskinxe2x80x9d surface or xe2x80x9cshinyxe2x80x9d side of the membrane. The increase in pore size between the skin surface and the opposite surface of the membrane is generally gradual, with the smallest pore size nearest the skin surface and the largest pores being found at or adjacent to the opposite, coarse-pored surface, generally referred to as the xe2x80x9copenxe2x80x9d surface or the xe2x80x9cdullxe2x80x9d side of the membrane. Another variety of asymmetric membrane, commonly described as having a xe2x80x9cfunnel-with-a-neckxe2x80x9d structure, includes both an asymmetric region and an isotropic region, the isotropic region having a uniform pore size. The isotropic region typically extends from the skin surface of the membrane through about 5-80% of the thickness of the membrane, more preferably from about 15-50% of the thickness of the membrane.
The membranes of preferred embodiments also have a porous supporting structure between the two sides of the membrane. The nature of the porous supporting structure of a membrane may depend on the composition of the casting dope and the coagulation bath. The supporting structure can include closed cells, open cells of substantially the same pore size from one side of the membrane to the other, open cells with a gradation of pore sizes from one side of the membrane to the other, or finger-type structures, generally referred to as xe2x80x9cmacrovoids.xe2x80x9d Macrovoids typically vary substantially in size from the surrounding porosity, and generally do not communicate with surface pores. In a preferred embodiment, the porous supporting structure includes a network of structural surfaces capable of contacting a filter stream, defined herein as including any fluid substance, including liquids and gases, that passes through the membrane via the porous supporting structure.
Whether the membrane has an isotropic, asymmetric or funnel-with-a-neck structure can depend upon several factors involved in the preparation of the membrane, including the type and concentration of the polymer, the solvent, and the nonsolvent; the casting conditions such as the knife gap, and the dope temperature; environmental factors such as the exposure time between casting and quenching, and the humidity of the exposure atmosphere; and the composition and temperature of the quench bath. In various embodiments, the asymmetry in pore size between the skin side and dull side of the membrane may typically be from about 1:2, 1:5, 1:10, 1:20, 1:50, 1:100, or 1:200 to about 1:1,000 or 1:10,000 or greater, more preferably from about 1:2, 1:5, 1:10, or 1:20 to about 1:50, 1:100, 1:200 or 1:1,000.
Membranes that are suitable for grafting in accordance with the present invention include virtually any formed hydrophobic or hydrophilic polymer membranes. Suitable membranes may typically have pore diameters from about 0.001 xcexcm to about 50 xcexcm or greater, preferably from about 0.01 xcexcm to about 50 xcexcm, on the skin side of the membrane. Membranes that are suitable for coating in accordance with the preferred embodiments include, for example, membranes that typically possess porosities characteristic of microfiltration membranes. Microfiltration membranes typically possess pore diameters of from at least about 0.01 or 0.05 xcexcm to about 5, 8, 10 or 20 xcexcm on the skin side of the membrane. Membranes within the ultrafiltration range may also be grafted according to preferred embodiments. Ultrafiltration membranes typically possess molecular weight cutoffs of from about 10,000 Daltons to about 1,000,000 Daltons and may have pore diameters typically from about 0.001 xcexcm to about 0.050 xcexcm on the skin side of the membrane.
Particularly preferred membranes before post treatment, such as crosslinking or grafting, include the highly asymmetric polyethersulfone membranes disclosed in U.S. Pat. No. 5,886,059 (incorporated herein by reference in its entirety). In typical highly asymmetric PES membranes, one side of the PES membrane is a skin face having relatively small diameter pores while the opposite or dull face of the membrane has relatively large diameter pores. The difference in porosity between the skin face and the opposite face is typically from at least about 1:2, 1:5, or 1:10 to about 1:20, 1:50, 1:100, 1:200 or 1:10,000. Preferably, the difference in porosity is from about 1:2 to about 1:10,000. More preferably, the difference in porosity is from about 1:2 to about 1:200. Most preferably, the difference in porosity is from about 1:5 to about 1:20. In addition, such membranes generally have a gradual slope of pore size from the skin face to the opposite face. Thus, during filtration, larger particles can enter the membrane through the larger pores, but do not exit through the smaller pores. Because the larger particles become lodged just within the outer surface, the membranes made by the methods included herein are not easily clogged with large particles.
In another preferred embodiment, the substrate is a microporous PVDF polymer membrane having a microporous surface with minimum pores, and an opposite surface with maximum pores. Such membranes may be prepared from PVDF HYLAR-461, (available from Ausimont USA, Inc. of Thorofare, N.J.) and may also typically contain from about 1% to about 30% by weight of polyvinylpyrrolidone (PVP).
Hydrophilic membranes may also be coated according to the present invention. Such hydrophilic membranes include hydrophobic membranes that have been post-treated with a surfactant or other material capable of rendering the membrane hydrophilic, as well as membranes prepared from a casting dope containing a hydrophilic material in addition to a hydrophobic polymer.
The filtration media of the preferred embodiments may include composite membranes. Composite membranes are membranes having multiple layers, and are preferred in a variety of separations applications. In many cases, the various layers of a composite membrane each impart different desirable properties to the composite. For example, in some applications, an extremely thin membrane may have advantageous flow rates in separations of very small particles, gases, and the like. Yet such a thin membrane may be fragile and difficult to handle or to package into cartridges. In such cases, the fragile, thin layer membrane may be combined with a backing or with a stronger, more porous membrane, to form a composite having improved strength and handling characteristics without sacrificing the separation properties of the thin layer membrane. Other desirable properties imparted by laminating a membrane to another media may include increased burst strength, increased thickness, providing prefiltration capability, and providing an adhesive layer to facilitate assembly of a device.
Composite membranes may be prepared using lamination techniques. In lamination, sheets are layered together in a stack, optionally with one or more adhesive materials placed between the sheets to facilitate binding and lamination of the sheets to each other, and the stack is laminated into an integral composite membrane under application of heat and/or pressure. A different approach to making composite membranes is to cast or form one membrane layer in situ on top of another layer. The base layer may be a fibrous backing material or it may be a membrane. The composites may include, for example, composites having different layers of any of the foregoing media, composites having multiple layers of the same medium, or composites having layers of the same medium, but of different pore sizes, porosities, geometries, orientations, and the like. The composite may be formed either before or after a membrane component is coated with a fluorosulfone oligomer according to a preferred embodiment.
Composite filtration media of the preferred embodiments are not limited to composites including membranes. Composites including other filtration media, for example, nonwoven or woven fibers or any other suitable non-membrane filtration media, are also contemplated.
In one type of composite, an oleophobic filtration medium of the preferred embodiment is bonded to a textile fabric or other woven or nonwoven material to form a layered fabric capable of excluding the passage of liquid while allowing passage of vapors and gases therethrough. Such a layered fabric may be preferred in a variety of applications, as will be appreciated by those of ordinary skill in the art. Bonding an oleophobic filtration medium, such as a membrane, to a fabric may be accomplished by conventional adhesives, thermal bonding, and the like. In this embodiment, the filtration medium may be coated prior to layering, or the coating may be applied simultaneously with, during, or after the layering of the filtration medium with the fabric.
Any polymer capable of being processed into filtration media using conventional methods, such as, for example, melt-blown techniques, or that can be formed into a membrane by a casting or other process and that can be rendered oleophobic by grafting with fluorosulfone oligomer is generally suitable for use in the present invention. Generally, oleophobicity is a characteristic of materials exhibiting repulsion to oils. Oleophobic materials repulse oils and possess a low surface tension value and are wettable by low surface tension liquids such as alcohol.
The Fluorosulfone Oligomer
The substrates of a preferred embodiment are rendered oleophobic through grafting the fluorosulfone oligomer to the polymer of the substrate such that a covalent bond is formed. Fluorosulfone oligomers suitable for use in preferred embodiments include those incorporating a functional group capable of grafting to the polymer of the substrate. The term xe2x80x98oligomerxe2x80x99, as used herein, is a broad term and is used in its ordinary sense, including, without limitation, oligomers incorporating up to about 20 or more repeat units, for example from about 1, 2, 3, 5, 10, 12, or 15 up to about 20 or more repeat units. For membranes having smaller pore sizes, oligomers having fewer repeat units are preferred. When the substrate to be coated is a larger pore membrane, oligomers having shorter or longer chain lengths may be preferred. Generally, the larger the pore size of the membrane, the longer the chain length of the oligomer that may be preferred to coat the membrane without significant pore blockage. However, longer chain length oligomers tend to be less reactive than a corresponding oligomer having a shorter chain length. Thus, if the polymer substrate is resistant to grafting, a shorter oligomer chain length may be preferred.
More than one fluorosulfone oligomer may be employed simultaneously. The fluorosulfone oligomers may differ, for example, in chemistry and/or chain length. The fluorosulfone oligomer as preferred herein has the ability to cause a surface to have decreased wettability by a low surface-tension fluid. Wetting, by definition, is the process of one fluid, including a liquid or a gas, displacing another fluid at a solid surface. However, in most cases, the term is used to describe the displacement of air by a liquid.
Suitable fluorosulfone oligomers may contain chemical functional groups such as acrylate or methacrylate groups and the like. In a preferred embodiment, the fluorosulfone oligomer is polyfluorosulfone acrylate. A nonlimiting example of such a fluorosulfone oligomer is one having the following structure:
CnF2n+1SO2N(CH2CH2)CH2CH2OCOxe2x80x94(CH2xe2x80x94CH2)mxe2x80x94CHxe2x95x90CH2
wherein n and m are integers up to about 20 or more, typically from about 1, 2, 3, 5, 10, 12, or 15 up to about 20 or more, preferably from about 2, 3, or 5 up to about 10, 12, 15 or 20, more preferably from about 5 to about 10, 12, 15, or 20, and most preferably greater than about 10.
The fluorosulfone oligomer is preferably applied to the polymeric substrate in the form of a solution. Suitable solvents include both polar and nonpolar solvents, including fluorocarbons, hydrocarbons, and alcohols such as, for example, isopropanol. Preferably, the solvent is not a solvent of the substrate. In a preferred embodiment, a mixture of isopropanol and water is preferred as the solvent. Nonlimiting examples of other suitable solvents include t-amyl alcohol, 2-methoxyethanol, ethanol, and methanol. The solubility of the fluorosulfone oligomer may be limited in certain solvents, resulting in formation of a suspension or emulsion. It is also suitable to apply the fluorosulfone oligomer to the polymeric substrate from such a suspension or emulsion.
The oligomer solution contains sufficient fluorosulfone oligomer to render the coated membrane sufficiently oleophobic without substantial pore blockage. The oligomer solution may contain from about 0.05 wt. % or less to about 40 wt. % or more of the oligomer, preferably from about 0.1 wt. % to about 10 wt. %, more preferably from about 0.5 to about 5 wt. %, and most preferably from about 1 to about 2 wt. %. At higher concentrations, substantial blockage of the membrane""s pores may be observed, resulting in lower airflow through the membrane. At lower concentrations, insufficient quantities of fluorosulfone oligomer may be available for grafting, resulting in a coated membrane that is not sufficiently oleophobic. In either case, the performance of the coated filtration medium may be less satisfactory, or even unsatisfactory, when compared to that of a coated filtration medium prepared from a solution in the preferred range. The optimal concentration of oligomer may vary depending upon the substrate to be coated. For example, the optimal concentration of oligomer may be lower for a membrane with smaller pore sizes and higher for a membrane with larger pore sizes or a loosely woven substrate.
The solution may also optionally contain one or more grafting initiators. A suitable grafting initiator is 2-hydroxy-2-methyl-1-phenyl-propan-1-one. The concentration of the grafting initiator in the solution may be from about 0.05 wt. % to about 1 wt. %, preferably from about 0.1 wt. % to about 0.5 wt. %, and more preferably from about 0.1 wt. % to about 0.2 wt. %.
The Grafting Process
The grafting process involves immersing the polymer substrate in the oligomer solution and allowing the solution to substantially penetrate the substrate. An immersion time of from about 1, 5, 10 or 15 seconds to about 1, 2, 5 or more minutes is typically sufficient to allow the oligomer solution to saturate the substrate. More typically, an immersion time of from about 15 seconds to about 2 minutes is preferred. Immersion times of from about 30 seconds to one minute are most preferred. Other times may be advantageous depending on the membrane and the oligomer formulation. The immersion of the substrate in the solution may be conducted at any suitable temperature, preferably at ambient temperature.
After the oligomer is applied to the polymer substrate by contacting the substrate with, for example, a solution, dispersion or emulsion of the oligomer, the oligomer is grafted to the substrate to yield an oleophobic-coated substrate. Grafting may be initiated by any suitable method. A few nonlimiting examples of approaches to grafting the fluorosulfone oligomer to a polymeric substrate include use of a grafting initiator such as 2-hydroxy-2-methyl-l-phenyl-propan-1-one, exposure to ultraviolet (UV) radiation, or heating to a temperature sufficient to induce grafting. Suitable temperatures may typically include, for example, a temperature from just above ambient up to the highest temperature that the filter is capable of withstanding without sustaining substantial damage, typically just below the melting point of the lowest melting component of the filter. A temperature above 100xc2x0 C. is preferred.
In a preferred embodiment, after contacting the substrate with the oligomer solution, the substrate is removed from solution and exposed to radiation to induce grafting of the oligomer to the polymer of the substrate. Suitable types of radiation include UV radiation, mixed-color light, infrared radiation, microwave radiation, or any other radiation capable of inducing grafting. UV radiation is preferred because it is particularly effective in inducing grafting. UV radiation has a wavelength of from about 15 nm up to about 400 nm. The wavelength of the UV radiation preferred for inducing grafting is typical of that of UV-C radiation, which includes wavelengths of from about 15 nm up to about 280 nm. More preferably, the wavelength of the UV radiation is about 254 nm. When grafting is induced by UV radiation, irradiation times typically will be from about 10 seconds, 15 seconds, 30 seconds, 1 minute, two minutes, five minutes, ten minutes, thirty minutes or more up to about 1 hour, 2 hours or more. Other times may be preferred, depending upon the nature of the substrate and oligomer, as will be appreciated by one of skill in the art. More typically, the irradiation time is from about one minute up to about one hour, most typically about 1 hour. The irradiation time may depend upon the ease or difficulty in inducing grafting of the fluorosulfone oligomer to the polymer of the substrate. Generally, the more inert the polymer, the more UV irradiation time is required. The irradiation may be conducted in an inert atmosphere, such as, for example, a nitrogen or argon purge.
After the irradiation is completed, the coated substrate is preferably rinsed to remove residual oligomer. Suitable rinsing solutions may include water, alcohol, mixtures of water and alcohol, or any other solvent capable of removing residual oligomer without causing substantial damage to the coated membrane. It is also preferable to dry the coated substrate at an elevated temperature, for example, in an oven. Drying temperatures may be between a temperature slightly above ambient to any higher temperature that the coated membrane is capable of withstanding without substantial damage. For example, drying temperatures of from about 100xc2x0 C. to about 150xc2x0 C. are typically preferred for coated polysulfone substrates. Alternatively, the coated substrate may be dried by any other suitable method that does not substantially affect the performance or integrity of the coated substrate, such as, for example, air-drying.
The substrate is preferably coated with an amount of fluorosulfone oligomer sufficient to impart oleophobicity to the coated filter without substantially affecting airflow through the filter.
The Coated Substrates
The relative oleophobicity of modified filters and unmodified substrates is determined by testing the filters and substrates (collectively xe2x80x9cfiltration mediaxe2x80x9d) for their ability to be wetted by a low surface-tension fluid. A drop of 2-methoxyethanol having a surface tension of 31.8 dynes/cm2 at 15xc2x0 C. is gently placed on the surface of the filtration medium using a glass pipette, and the wetting time is recorded. If the medium is not wetted by the 2-methoxyethanol within 30 seconds, the result is recorded as xe2x80x9cNo Wettingxe2x80x9d. The filtration media of the preferred embodiments are generally resistant to wetting by 2-methoxyethanol, and are relatively more oleophobic than untreated substrates.
Airflow through a filtration medium is measured in units of Gurley Flow. Gurley Flow is the time in seconds it takes 300 ml of air to pass through a 1xe2x80x3 diameter membrane under the force of a 5 oz weight. Gurley Flow may be measured using a Model 4320 GENUINE GURLEY(trademark) Densometer manufactured by Gurley Precision Instruments of Troy, N.Y.
A detergent solution penetration test is preferred to determine a membrane""s resistance to penetration by a dilute solution of a dishwashing detergent. The detergent solution mimics the behavior of a vitamin solution in contact with a membrane in an intravenous line. A consumer grade dishwashing detergent, such as Dawn(trademark) available from Proctor and Gamble of Cincinnati, Ohio, is diluted to produce a 1:100 solution in water. The solution is contacted to one side of a 25 mm diameter membrane to be tested, and one meter of head pressure is applied. If no detergent solution penetrates the membrane after one minute, then the membrane has passed the detergent flow test.
Water penetration is determined by measuring the pressure in pounds per square inch differential (psid) required to force water through the filtration medium. Pounds per square inch differential is the difference in pressure existing on opposite sides of a filtration medium. In comparing two filtration media having similar porosity, the water penetration pressure correlates with the filtration medium""s relative hydrophobicity, wherein a high water penetration pressure indicates that the filtration medium is more hydrophobic than a filtration medium having a lower water penetration pressure.

Oleophobic membrane materials by oligomer polymerization for filter venting applications


An ice delivery system includes an ice bin with an ice maker thereon. An auger dispenses ice from the bin and agitators within the bin prevent blockage. The agitation may follow a pattern depending on the location of the agitators with some about the periphery less employed than those adjacent the auger. An ice gate receives ice and flowing air to direct the ice pneumatically to a multistation diverter. The flow through the diverter is vertically downwardly. Tubes from the diverter convey ice to remote dispensing stations. The dispensing stations have prechambers with drains and lockable gates to advantageously receive ice for delivery into the remote station bins or block the ice storage area to allow cleaning. Conduit couplings are configured to connect tubing without creating an area of ice blockage or allowing the buildup of contamination. Germicidal lights or ozone may be used in the ice bin to avoid contamination. Further, active agents for cleaning, de-scaling or sanitizing may be introduced through the ice gate on an automatic is cycled basis.

The field of the present invention is pneumatic ice distribution to dispensing stations.
Apparatus and methods for distributing ice to remote stations have been developed, particularly for use in the food service industry. Such systems incorporate a central ice bin, transport conduits, remote dispensing stations and a source of pneumatic energy to move the ice from the central bin to the dispensing stations. One such system is illustrated in U.S. Pat. No. 5,549,421, the disclosure of which is incorporated herein by reference.
In designing such systems, important considerations include enhancing ice flow, maintaining the integrity of the ice in a frozen state and avoiding contamination. In operating such systems, ice has been found to have a tendency to stick together and form blockages in the handling system. Avoidance of such blockages and the proper handling of a blockage when it does occur are of critical importance to the reliability to such systems. Maintaining the ice in an appropriate frozen state is also important. Localized thawing followed by re-freezing encourages the agglomeration of pieces of ice, resulting in blockage and inappropriate dispensing. The quality of the ice dispensed also is dependent upon the appropriate maintenance of uniform temperatures. Contamination has been a problem in such systems. Ice bins form a convenient source for manually taking scoops of ice. Further, placing foreign objects, such as glasses and bowls, in the ice for chilling has also been found to be a common, if inappropriate, use of ice bins. Resolutions of these issues is necessary for public safety and commercial acceptance of such systems.
The present invention is directed to an ice delivery system including various mechanical components therefor and modes of operation.
In a first separate aspect of the present invention, the ice delivery system includes a source of ice, an ice bin and two sets of at least one agitator each. Each set of at least one agitator includes a periodic cycle. The frequency of the periodic cycle of the set closest to the bin outlet is substantially greater than the frequency of the periodic cycle of the other set. Ice is thus able to move through the bin without bridging or blockage and, at the same time, without being excessively stirred.
In a second separate aspect of the present invention, the ice delivery system of the first aspect may have a ratio of frequencies between sets of 10:1. Additionally, the agitators may move less than one full revolution for each periodic cycle. The bin may have a V-bottom with an augur located at the convergence of the V-bottom. Various agitator configurations are contemplated. Agitators adjacent to the augur may include augur elements oriented to move ice away from the outlet. The augur may be of increasing pitch toward the bin outlet. Each contributes to consistent flow through the bin and discharge.
In a third separate aspect of the present invention, an ice delivery system includes an ice bin with a channel in the bottom thereof leading to an outlet. The outlet has a larger horizontal major cross-sectional dimension than the channel. An augur is rotatably mounted in the channel. The augur may extend outwardly of the ice outlet. Reduced blockage is contemplated. A breaker element may be arranged adjacent the augur outwardly of the ice outlet to avoid further any ice buildup.
In a fourth separate aspect of the present invention, an ice delivery system includes a multi-station diverter. The diverter is associated with an ice transport conduit and with distribution conduits which extend to a plurality of receiving stations. The ice transport conduit extends downwardly to the diverter while the distribution conduits extend downwardly from the diverter at the portions of those conduits adjacent the diverter. This orientation of the conduits avoids ice blockage in the diverter. The downward orientation of the conduits may additionally be vertical to further inhibit ice blockage.
In a fifth separate aspect of the present invention, the ice delivery system includes a multi-station diverter including a rotatably mounted diverter tube which has an inlet end concentric with the axis of rotation and an outlet end displaced from the axis by a fixed distance. A transport conduit is associated with the inlet end while distribution conduits are placed about the axis of rotation at the same distance as the outlet end of the diverter tube. A conduit is thus presented through the diverter matching up with the incoming transport conduit and the outgoing distribution conduits.
In a sixth separate aspect of the present invention, the multi-station diverter of the fifth separate aspect is contemplated to include further a support for the diverter tube which has sockets cooperating with an actuated pin to properly align the diverter tube with the distribution conduit inlets. Station markers may be associated with the support to provide input to a controller for properly locating the diverter tube.
In a seventh separate aspect of the present invention, the ice delivery system includes an air directional valve and a source of constant transporting air. The valve includes valve elements which selectively open to alternatively supply air to an ice transport conduit and to exhaust. In this way, the source of constant transporting air may be rapidly applied and rapidly diverted from the pneumatic conveyor.
In an eighth separate aspect of the present invention, the ice delivery system includes an ice transport conduit, a controlled source of transporting air and an ice gate which includes a substantially vertically extending passage, an ice inlet open laterally into the passage, an air inlet open into the passage below the ice inlet and an ice and air outlet below the air inlet. A gate in the passage has two extreme positions. One of the positions closes off the ice inlet to avoid air flow toward the ice inlet while the other provides for charging of ice into the transport conduit from the ice inlet.
In a ninth separate aspect of the present invention, the ice delivery system includes an ice bin and receiving stations with a pneumatic system for selectively distributing ice from the ice bin to the receiving stations. Ice level sensors are located in the bin and the receiving stations. A visual ice level monitor is coupled with the bin for maintaining the integrity of ice within the bin. A locking element may further restrict entry.
In a tenth separate aspect of the present invention, an ice delivery system conduit coupling has two end pieces, each with a tubular clamp section and a tubular extension section. The tubular extension sections have inner shoulders facing the tubular clamp sections and have attachments with sealing surfaces. The sealing surfaces are engaged facing one another with a sealing element therebetween. The tubular extension sections each have an inner shoulder facing the tubular clamp sections and inner truncated conical surfaces. One of the inner truncated conical surfaces tapers inwardly from the associated shoulder while the other tapers outwardly from the associated shoulder. The arrangement provides a coupling which is to avoid ice blockage. The tubular clamp sections may optionally be partially split longitudinally and include circumferential channels to receive clamp bands.
In an eleventh separate aspect of the present invention, an ice delivery system conduit coupling includes a coupling tube with a clamp sleeve extending thereover. The clamp sleeve includes longitudinally split ends and circumferential channels about the split ends which may receive clamp bands. The coupling tube fits within the clamp sleeve between annular sealing flanges located on the inner surface of the clamp sleeve. Conduit ends extend between the coupling tube and the clamp sleeve at either end thereof. Sealing and resistance to ice blockage are to be achieved by the annular sealing flanges capable of constricting the conduit to form sealed smooth transitions with the coupling tube.
In a twelfth separate aspect of the present invention, an ice delivery system conduit coupling includes a tubular insert having a flared end on an internal tubular surface and an external surface to receive the end of a conduit. A second portion of the tubular insert may also include a flared end and an external surface to receive another end of a conduit. A passage through the tubular insert may be larger toward the upstream end than toward the downstream end. In appropriate circumstances, a split sleeve may be wrapped about the tubular insert to extend beyond the insert for constricting the tubing for sealing and avoiding ice blockage.
In a thirteenth separate aspect of the present invention, the ice delivery system includes an ice bin with a germicidal aspect. This could be a germicidal light in the ice bin or a source of ozone. The presence of the germicidal light or the ozone is to reduce organic growth within the ice bin which might otherwise contaminate the ice.
In a fourteenth separate aspect of the present invention, the ice delivery system includes a remote dispensing station, a chamber between the distribution conduit and the remote dispensing station with a passageway from the chamber to the station. A gate selectively closes the passage as controlled by a system controller. Closure of the gate can prove advantageous to avoid blowing air, cleaning fluid or a sanitizing device into the remote station.
In a fifteenth separate aspect of the present invention, the ice delivery system of the fourteenth separate aspect might further include a liquid drain at the end of the gate to divert liquid from the receiving station. The gate may be both lockable by the controller in the closed position and independently biased toward the closed position.
In a sixteenth separate aspect of the present invention, the ice delivery system includes a drain at the end of a gate in a passage to a remote dispensing station. The drain exits from the end of the gate with the gate closing the passage. The drain may include a collector extending across the distal end of the gate with an outlet at one edge of the gate. The collector may be a trough in one surface of the gate or the collector may extend through the wall of the passage at the distal end of the gate with the gate in the closed position.
In a seventeenth separate aspect of the present invention, the ice delivery system includes auguring ice from a bin, dropping the ice away from the augur, timing a delay after auguring the ice before closing a gate and blowing transporting air to convey the ice. Where appropriate, the augur may be reversed before closing the gate. This allows ice to properly pass into the transporting area from the ice bin.
In an eighteenth separate aspect of the present invention, the ice delivery system includes auguring ice from an ice bin, dropping the ice away from the augur outside of the bin, closing a gate between the bin and a source of transporting air and sensing the state of closure of that gate. Cycling the action to close the gate until the gate is fully closed helps to clear away any ice blocking complete closure of the gate which might otherwise result in insufficient conveying pressure to convey the ice.
In a nineteenth separate aspect of the present invention, the ice delivery system includes auguring ice from a bin, dropping the ice away from the augur, stopping the augur, closing a gate to the ice bin, storing pressure in a source of transporting air and rapidly releasing that air to blow transporting air and provide an initial boost to provide momentum to the ice being transported.
In a twentieth separate aspect of the present invention, the ice delivery system includes auguring ice from an ice bin and transporting that ice through distribution conduits. The auguring of ice is disabled upon the opening of an access door into the ice bin. Once disabled, upon closure of the ice bin door, a test puff of air may be employed for determining the presence of ice in the distribution system. Maintaining ice bin integrity and reinitializing the distribution system inhibits contamination and avoids system blockage.
In a twenty-first separate aspect of the present invention, the ice delivery system initializes the system upon powering up, either initially or upon restart after system shutdown. The blowing of transporting air is cycled upon the sensing of a predetermined minimum pressure in the ice transport conduit.
In a twenty-second separate aspect of the present invention, the ice delivery system includes testing the system for blockage before auguring ice from the bin and blowing a burst of transporting air through the system before auguring ice upon sensing a pressure above a preset value within the distribution conduit.
In a twenty-third separate aspect of the present invention, the ice delivery system provides for the blowing of transporting air without release of the gate at the remote dispensing station. The blowing of transporting air with the gate closed at the remote station accommodates a drying cycle as well as a cleaning cycle without affecting the ice within the remote station.
In a twenty-fourth separate aspect of the present invention, the gate associated with a remote dispensing station may be employed to sense the state of the remote dispensing station and disable the distribution of ice thereto when appropriate.
In a twenty-fifth separate aspect of the present invention, the ice delivery system includes the mode of blowing drying air through the system to inhibit the growth of contaminating agents.
In a twenty-sixth separate aspect of the present invention, the ice delivery system includes the cycle of transporting ice pneumatically through tubing from an ice bin to a remote dispensing station with a gate to the remote dispensing station closed, adding an active agent to the ice to be transported and blowing air through the tubing and over the transported ice. The active agent may be drained from the ice before entering the remote dispensing station.
In a twenty-seventh separate aspect of the present invention, any of the foregoing aspects are contemplated to be employed in combination.
Accordingly, it is a principal object of the present invention to provide an improved process and the apparatus therefor for distributing ice from a central station. Other and further objects and advantages will appear hereinafter.

Method and apparatus for the distribution of ice


Inhibitors of JAK3 kinase for the treatment of allergy inhibit mast cell degranulation an dmediator release.

Signal transducers and activators of transcription (STAT) are pleiotropic transcription factors which mediate cytokine-stimulated gene expression in multiple cell populations (D. A. Levy, Cytokine Growth Factor Rev., 8:81 (1997)). All STAT proteins contain a DNA binding domain, a Src homology 2 (SH2) domain, and a transactivation domain necessary for transcriptional activation of target gene expression. Janus kinases (JAK), including JAK1, JAK2, Tyk, and JAK3, are cytoplasmic protein tyrosine kinases (PTKs) which play pivotal roles in initiation of cytokine-triggered signaling events by activating the cytoplasmic latent forms of STAT proteins via tyrosine phosphorylation on a specific tyrosine residue near the SH2 domain (See J. N. Ihle et al., Trends Genet., 11:69 (1995); J. E. Darnell et al., Science, 265:1415 (1994); J. A. Johnston et al., Nature, 370:1513 (1994)). Tyrosine phosphorylated STAT proteins dimerize through specific reciprocal SH2-phosphotyrosine interactions and translocate from the cytoplasm to the nucleus where they stimulate the transcription of specific target genes by binding to response elements in their promoters (See W. J. Leonard, Nature Medicine, 2:968 (1996); Z. Zhong et al., PNAS USA, 91:4806 (1994) Darnell et al., Science, 264:1415 (1994)).
Among the four members of the JAK family, JAK3 is abundantly expressed in lymphoid cells and plays an important role in normal lymphocyte development and function, as evidenced by qualitative and quantitative deficiencies in the B-cell as well as T-cell compartments of the immune system of JAK3-deficient mice (T. Nosaka et al., Science, 270:800 (1995); D. C. Thomas et al., Science, 270:794 (1995)) and development of severe combined immunodeficiency in JAK3-deficient patients (R. H. Buckley et al., J. Pediatr., 130:379 (1997)). Besides lymphoid cells, non-lymphoid cells, including monocytes, megakaryocytes, endothelial cells, cancers cells, and, as described herein, mast cells also express JAK3, but no information is currently available regarding the physiologic function of JAK3 in these non-lymphoid cell populations. See, D. C. Thomas et al., Curr. Opin. Immunol., 9:541 (1997); J. N. Hile, Philos. Trans. R. Soc. Lond B Biol. Sci., 351:159 (1996); J. W. Verbsky et al., J. Biol. Chem., 271:13976 (1996).
JAK-3 maps to human chromosome 19p12-13.1. A cluster of genes encoding protooncogenes and transcription factors is also located near this region. JAK-3 expression has been demonstrated in mature B-cells as well as B-cell precursors. JAK-3 has also been detected in leukemic B-cell precursors and lymphoma B-cells. The physiological roles for JAK-3 have been borne out through targeted gene disruption studies in mice, the genetic analysis of patients with severe combined immunodeficiency, and biochemical studies of JAK-3 in cell lines. A wide range of stimuli result in JAK-3 activation in B-cells, including interleukin 7 and interleukin 4. The B-cell marker CD40 constitutively associates with JAK-3 and ligation of CD40 results in JAK-3 activation, which has been shown to be mandatory for CD40-mediated gene expression. Constitutive activity of JAK-3 has been observed in v-abl transformed pre-B cells and coimmunoprecipitations show that v-abl physically associates with JAK-3, implicating JAK-3 in v-abl induced cellular transformation. See J. N. Ihle, Philos Trans R Soc Lond B Biol Sci, 351:159 (1996); W. J. Leonard et al., Cytokine Growth Factor Rev., 8:81 (1997); M. C. Riedy et al., Genomics, 37:57 (1996); M. G. Safford et al. [published erratum appears in Exp. Hematol., 1997 July; 25(7):650] Exp. Hematol., 25:374 (1997); A. Kumar et al., Oncogene, 13:2009 (1996); S. M. Hoffman et al., Genomics, 43:109 (1997); P. J. Tortolani et al., J. Immunol., 155:5220 (1995); N. Sharfe et al., Clin. Exp. Immunol., 108:552 (1997); C. B. Gurniak et al., Blood, 87:3151 (1996); C. Rolling et al., Oncogene, 10:1757 (1995); C. Rolling et al., FEBS Lett., 393:53 (1996); S. H. Hanissian et al., Immunity, 6:379 (1997); N. N. Daniel et al., Science, 269:1875 (1995).
Acute allergic reactions, also known as immediate (type I) hypersensitivity reactions, including anaphylaxis with a potentially fatal outcome, are triggered by three major classes of proinflammatory mediators, namely preformed, granule-associated bioactive amines (e.g., histamine, serotonin) and acid hydrolases (e.g., .beta.-hexosaminidase), newly synthesized arachidonic acid metabolites [e.g., leukotriene (LT) C.sub.4, prostaglandin D.sub.2, and platelet activating factor], and a number of proinflammatory vasoactive cytokines (e.g., tumor necrosis factor [TNF] .alpha., interleukin-6 [IL-6]) (R. Malavija et al., J. Biol. Chem., 268:4939 (1983); S. J. Galli et al., N. Eng J. Med., 328:257 (1993)). These proinflammatory mediators are released from sensitized mast cells upon activation through the antigen-mediated crosslinking of their high affinity cell surface IgE receptors/Fc.epsilon. RI (M. J. Hamany et al., Cellular Signaling, 7:1535 (1995); A. M. Scharenberg et al., Clin. Immunol., G. Marone ed., Basel, Karger (1995) at p. 72)). IgE receptor/Fc.epsilon.RI is a multimeric receptor with .alpha., .beta., and homodimeric .gamma. chains (See U. Blank et al., Nature, 337, 187 (1989)). Both .beta.- and .gamma. subunits of the IgE receptor/Fc.epsilon.RI contain ITAMs (Immunoreceptor Tyrosine-based Activation Motifs) which allow interaction with protein tyrosine kinases (PTK) and PTK substrates via their SH2 domains (See, N. Hirasawa et al., J. Biol. Chem., 270:10960 (1995)). The engagement of IgE receptors by antigen triggers a cascade of biochemical signal transduction events, including activation of multiple PTK (S. E. Lavens-Philips et al., Inflamm. Res., 47:137 (1998)). The activation of PTK and subsequent tyrosine phosphorylation of their downstream substrates have been implicated in the pathophysiology of type I hypersensitivity reactions (See K. Moriya et al., PNAS USA, 94:12539 (1997) Costello et al., Oncogene, 13:2595 (1996)).
Treatments for allergy are generally aimed at three possible components: 1) avoidance or reduced exposure to the allergen, which can be very difficult especially in case of children; 2) allergen immunotherapy, which only works for some allergens, and which is frequently ineffective; and 3) pharmacotherapy (medication), which is the most effective treatment. Allergy medication either should prevent the release of allergy causing chemicals such as histamine from mast cells, or stop the response of histamine on the tissues. Most currently available medications are anti-histamines. Usually in case of allergy and asthma, doctors prescribe second generation anti-histamines such as loraitidine (Claratin.RTM.), fexofenidine (Allegra.RTM.) or leukotriene synthesis inhibitors such as zafirlukast (Accolate.RTM.) and zileutron (Zyflo.RTM.). Because the airway is more sensitive to leukotrienes produced by a number of inflammatory cells, anti-leukotriene agents are usually more effective for asthmatic conditions.
Although the second generation antihistamines are as effective as the older ones (Benadryl and Chlortrimeton) they have two potential problems. First, these drugs only counteract the effect of histamine released by mast cells in the body, which are responsible for many but not all the symptoms of allergy. Therefore, anti-histamines are very effective in decreasing the itching, sneezing, and nasal secretions, but do not provide relief from nasal stuffiness and late phase allergic reactions. A number of inflammatory mediators other than histamine, such as leukotrienes and a number of vasoactive cytokines, are also released by mast cells and basophils. These inflammatory mediators remain unaffected by anti-histamines and contribute significantly to the patho-physiology of allergy and asthma. Sometimes a combination of anti-allergic and inflammatory drugs works better, but at the same time these combinations cause adverse side effects. Secondly, in more severe allergic reactions (anaphylaxis), anti-histamines do not have therapeutic effect.
Until recently, therapy for asthma was based on the drug theophylline. This drug is an excellent, time proven, time tested drug but had numerous side effects. In the 1980's short acting beta-adrenergic compounds were introduced. In the 1990's asthma therapy shifted, so that asthmatic patients started taking cortocosteroids, cromolyn, and theophylline in different combinations. Recently three anti-leukotriene drugs: Accolate, Zyflo and Singulair, were introduced in to the U.S. market for the treatment of asthma. These medications either block the release of leukotrienes (Zylec) or block their effect on tissues (Accolate). Each is available in tablet form to be taken 2 to 4 times a day. Although leukotriene inhibitors do not inhibit early phase of allergy or asthmatic reaction, they are found to improve pulmonary function and asthma symptoms and significantly reduce requirement of beta-agonist by reducing the bronchial hyper-responsiveness.
Despite the above described advances in therapy, there is currently a need for therapeutic agents and methods that are useful for preventing or reducing immediate (type I) hypersensitivity reactions, including anaphylaxis and other allergic reactions.

JAK-3 inhibitors for treating allergic disorders


An organic electronic device includes: a pair of electrodes, an organic film layer containing an organic substance having a benzothiadiazole skeleton, a metal oxide layer provided on the organic film layer by vacuum vapor deposition, and an interface formed between the pair of electrodes out of the organic film layer and the metal oxide layer.

1. Technical Field
The present invention relates to an organic electronic device and a method for manufacturing the same.
2. Related Art
Numerous researches are being conducted on organic electronic devices such as organic light emitting devices (LEDs) and organic thin film transistors (TFTs). In current techniques, however, it is necessary to select materials having energy levels appropriate for carrier injection from an electrode to an organic substance. This is based on an idea that the energy level of a material in a film used in the development of inorganic semiconductor devices is considered as a continuum band and that the junction is performed with sending and receiving of the carriers. For example, an organic LED requires an electrode appropriate for the highest occupied molecular orbital (HOMO) level and the lowest unoccupied molecular orbital (LUMO) level of the organic molecule. As a result, an active metal having a low work function needs be used on the cathode side (Non-Patent Document 1: Nature, vol. 357, p. 477, 1992). This requires a sealing structure which is a heavy burden in applications.
The amount of carrier injection is strongly influenced by the height of a barrier. Thus, with devices such as TFTs associated with the carrier injection, once a central organic semiconductor is determined, ingredients such as electrodes that turn the semiconductor into a device are automatically determined (Non-Patent Document 2: Synthetic Metals, vol. 111-112, p. 19, 2000). This greatly restricts an act of adding functional variety to the device or adding other functions to the device.


In one embodiment, a method includes by a robotic system: sending, by an automatic tuning controller, driving commands to actuators of the robotic system, performing, for each of the actuators, one or more measurements of an actual pose of the respective actuator in response to the driving commands, generating, for each of the actuators, one or more configuration parameters for the respective actuator based on the one or more measurements, and storing the configuration parameters for the actuators in a data store of the robotic system.

A robot is a machine, especially one programmable by a computer, capable of carrying out a complex series of actions automatically. Robots may be guided by an external control device or the control may be embedded within. Robots may be constructed on the lines of human form, but most robots are machines designed to perform a task with no regard to their aesthetics. Robots may be autonomous or semi-autonomous and range from humanoids to industrial robots, medical operating robots, patient assist robots, dog therapy robots, collectively programmed swarm robots, UAV drones, and even microscopic nano robots. By mimicking a lifelike appearance or automating movements, a robot may convey a sense of intelligence or thought of its own.
The branch of technology that deals with the design, construction, operation, and application of robots, as well as computer systems for their control, sensory feedback, and information processing is robotics. These technologies deal with automated machines that can take the place of humans in dangerous environments or manufacturing processes, or resemble humans in appearance, behavior, or cognition.

Systems and methods for automated tuning of robotics systems