Abstract: A filter unit for removing leukocytes from a leukocyte-containing suspension by passing the suspension through a filter unit. The filter unit may comprise a main filter for blocking the leukocytes and a post-filter for preventing leakage of the leukocytes having a higher median pore size than the main filter and placed downstream of the main-filter.

Abstract: The invention relates to charged filtration membranes and their use for separation of a protein from solvent, low molecular weight solutes or a mixture of proteins. Modification of the membranes to generate charge includes modification of membrane pores to alter charge within a pore and alter the size of a pore. Consequently, the protein is separated from other solutes in a mixture based on size as well as net protein charge and membrane charge.

Abstract: An improved wide passage cross-flow filtration cassette is disclosed that incorporates an open mesh matrix retentate spacer that is dimensioned and oriented so as to improve flux and cause turbulence in the flow of fluids through the cassette.

Abstract: A filter aid, in particular for filtering beverages by means of precoated filters, comprises a mixture of exclusively natural components, e.g. cellulose components. The filter aid is made only of sustainable raw materials and can be degraded almost totally in a natural way.

Abstract: The present invention relates to cationically charge-modified membranes and methods of preparing such membranes. In one major aspect of the invention, the membranes are hydrophobic membranes that are treated with one or more polymeric wetting agents to render the membranes substantially hydrophilic, followed by treatment with one or more charge-modifying agents, the agents causing the membranes to possess a fixed formal positive charge. In another major aspect of the invention, a cationic membrane is formed from casting in a film a mixed polymer solution comprising a sulfone polymer and a copolymer of vinylpyrrolidone and a cationic imidazolinium compound, and quenching the film in an aqueous bath to produce a coagulated membrane. The membrane can be further cationically charge-modified with one or more charge-modifying agents.

Abstract: A pore plugging material, for pH dependent membrane diffusion, in which cyclic olefins having phosphazene-functional moieties provide predictable erosion properties when used to plug pores in separation barriers and other porous membranes. Specific properties of the polymers are dependent on several factors, including molecular weight and identity of side groups attached to the phosphazene moiety. However, as a class, phosphazene-functional cyclic olefins provide both predictable erodibility and uniformly benign hydrolysis products and are, therefore, uniquely suitable as pore plugging polymers for separation barriers and membranes of all kinds. The invention, therefore, embraces the provision of a pH-sensitive erodible pore plugging material for pores in separation barriers and membranes of all kinds.

Abstract: Cast semi-permeable membranes made from synthetic polymer used in reverse osmosis, ultrafiltration and microfiltration are treated with a non-leaching antimicrobial agent to prevent its bio-fouling and bacterial breakthrough. The semi-permeable membranes include a polymeric material and a non-leaching antimicrobial agent that is incorporated into and homogeneously distributed throughout the polymeric material. The polymeric material, in the case of one membrane, may be cellulose acetate. In the case of thin film composite polyamide membranes, the antimicrobial agent is incorporated in a microporous polysulfone layer that is sandwiched between a reinforcing fabric and an ultrathin polyamide material. The invention also includes a treatment of flat and hollow fiber semipermeable membranes made with polysulfones and polyvinylidene fluoride.

Abstract: The present invention relates to ultra-thin high strength asymmetric microfiltration and ultrafiltration cellulosic membranes. The membranes are internally hydrophilic. A method of preparing such membranes and their use in separating proteins from biological liquids are also provided.

Abstract: Methods and apparatus for qualitatively or quantitatively determining one or more analytes in matrices such as foods, biological fluids, etc. An embodiment for determination of a single analyte comprises a sample receiving vessel, a first membrane and a reagent-containing well. The prepared sample passes through the first membrane whereby extraneous matter is removed, and a filtrate enters the reagent-containing well to provide a filtrate-reagent admixture from which the analyte may be determined. An embodiment for determination for multiple analytes includes one or more additional membranes in series with the first membrane, each such additional membrane being operative to capture one or more analytes. Each of the additional analytes may then be eluted from the membrane upon which it has been captured, into a separate reagent-containing well to provide eluant-reagent admixture from which each desired analyte may be determined. Formulations for preparation additives are also included.

Abstract: Asymmetric hydrophilic polymeric membranes are disclosed wherein the asymmetry between the pore diameters of the first and second membrane faces is at least about 2:1, and wherein the membrane comprises a hydrophobic polymer to which hydrophilic moieties have been covalently bonded. A method of preparing such membranes is provided, wherein an asymmetric hydrophobic polymeric membrane is immersed in a solution comprising a solvent, a free radical polymerization initiator, and a monomer having hydrophilic moieties, then exposed to an energy source, whereby the monomer is covalently bonded to the hydrophobic polymer of the membrane. A method of rendering a hydrophobic polymeric substrate permanently hydrophilic is disclosed, wherein a hydrophobic polymeric substrate is immersed in a solution of monomer and free radical polymerization initiator in an alkylene glycol solvent, then exposed to an energy source so as to covalently bond the hydrophilic monomer to the substrate.

Abstract: The invention pertains to a method for simultaneously removing metallic ions and particulate material from a pH neutral solution using particle-removing membranes (e.g., ultra high molecular weight polyethylene) having immobilized ligands that possess the capacity and high equilibrium binding constants for ion removal. The method is particularly useful for simultaneously filtering/purifying deionized water.

Abstract: A membrane having a refined surface as well as to a process and an apparatus for producing such a membrane, and which is useful, in particular, for rapid diagnostic tests for identifying specific analytes in liquid media.

Abstract: A membrane for use in a sensor having a detection arrangement. The membrane is of a cellulosic material incorporating a hydrophobic agent (e.g. isopropyl myristate) and is permeable by diffusion to an analyte species of interest to be detected directly or indirectly by the detection arrangement.

Abstract: To provide a cellulose acetate semipermeable membrane having a high filtration rate and high mechanical strength and which is hardly degraded by microorganisms, the present invention provides a cellulose acetate semipermeable membrane containing a cellulose acetate having an &agr;-cellulose content of not less than 99% by weight, a 6 wt/vol % viscosity of 20 to 220 mPa·s at 25±1° C. and an acetylation degree of 58 to 62%. The cellulose acetate semipermeable membrane is suitable particularly as a hollow fiber membrane.

Abstract: Novel solid phase reaction supports are disclosed. The solid phase reaction supports include (a) a solid phase carrier having a multiplicity of NH2 functional groups; (b) a coupling compound covalently bonded to an NH2 group of the solid phase carrier; and (c) a receptor compound coupled to the solid phase carrier through the coupling compound. The coupling compound is preferably ascorbic acid, dehydroascorbic acid or a diketo compound structurally similar to ascorbic acid or dehydroascorbic acid. The solid phase carrier is preferably made of cellulose.

Abstract: Novel solid phase reaction supports are disclosed. The solid phase reaction supports include (a) a solid phase carrier having a multiplicity of NH2 functional groups of the Formula (I): in which R1 and R2 are each H, or R1 is H and R2 is an alkyl or acyl substituent with a degree of substitution ≦1 or R1 is an alkyl or acyl substituent with a degree of substitution ≦1, and R2 is H, or R1 and R2 are each a substituent with a degree of substitution ≦2 and R3 is an aromatic substituent containing at least one free amino group having a substitution degree ≦1; (b) a coupling compound covalently bonded to an NH2 group of the solid phase carrier; and (c) a receptor compound coupled to the solid phase carrier through the coupling compound.

Abstract: A smooth-textured non-woven, superabsorbent particle-impregnated fibrous structure is disclosed. The web exhibits an improved smooth surface texture. The structure contains from 50% to 80% of ion sensitive SAP having a particle size of less than 200 microns, wood pulp fibers and cellulose acetate fibers, each in preferred specified amounts indicated herein. The superabsorbent, ion sensitive polymer particle-impregnated fibrous structure is made from an aqueous, wet-lay process in which an aqueous furnish comprises solids of fibers and superabsorbent, ion sensitive polymer and dissolved salt, such as preferably, Na2SO4. The furnish is passed over a moving foraminous support, such as a Fourdrinier wire, and a wet web structure is formed, followed by drying.

Abstract: This invention relates to a polyion complex separation membrane with a double structure, which is applicable in the separation process of a water-soluble mixture having ionic molecules or particles by means of reverse osmotic pressure for the purposes of recovering expensive ionic organic materials such as anionic emulsifiers from the waste water. More particularly, this invention relates to said membrane having anionic polymers, as substrate, which is immersed into a cationic polymer solution containing a multivalent ion cross-linking agent, by which a cross-linkage within the internal of the separation membrane is achieved, thereby forming an ion complex between ionic polymers of opposite ion at the surface of the separation membrane to yield a stable separation membrane of a double structure.

Abstract: A porous material is disclosed, made of a semi IPN type polymer alloy of a crosslinked polymer (A) obtained by the crosslinking polymerization of a crosslinking-polymerizable vinyl monomer and/or oligomer (a) with a non-crosslinked polymer (D) which is soluble in a solvent (B) capable of dissolving said monomer and/or oligomer (a) therein and subjecting said crosslinked polymer (A) to gelation but is insoluble in a coagulating solution (C) which is compatible with said solvent (B) but doesn't subject said crosslinked polymer (D) to gelation. A porous material excellent in mechanical strength as well as in heat resistance can be prepared. Various functional groups can be introduced into the surface of the porous material. Further, the pore diameter can be easily controlled.

Abstract: Supported separation membranes are disclosed wherein the permselective membrane is integral with a polymeric support of non-woven fibers having a particular air permeability, the integral membranes exhibiting far superior lifetimes and retention capability, especially for microorganisms.

Abstract: A method for producing an aqueous solution of a polymer having a phosphorylcholine group in which a polymerizable composition containing a polymerizable monomer having the phosphorylcholine group represented by the formula (1) is polymerized in the presence of a non-metal polymerization initiator soluble in a water-containing medium, to obtain a crude polymer aqueous solution, and the crude polymer aqueous solution is purified with a separation membrane, and an aqueous solution of the polymer having the phosphorylcholine group obtained by the method and having not more than 2000 ppm of impurities.