Abstract: In one aspect, the magnetic recording medium comprises a magnetic layer comprising a ferromagnetic powder and a binder and said binder comprises polyurethane resin having a glass transition temperature of 100 to 200° C. In a second aspect, the magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a ferromagnetic powder and a binder in this order on a nonmagnetic support and at least the binder comprised in said magnetic layer comprises polyurethane resin having a glass transition temperature of 100 to 200° C. In both aspects, said magnetic layer has a thickness equal to or less than 0.15 ?m, said ferromagnetic powder has a mean major axis length or a mean plate diameter of 60 nm or less, and said magnetic layer has a coercivity of 159 to 239 kA/m in a longitudinal or in-plane direction.

Abstract: The present invention relates to a magnetic disk substrate formed of a thermoplastic resin and a magnetic disk comprising a magnetic recording layer formed on the magnetic disk substrate. In the magnetic disk substrate of the invention, the amount of gases generated therefrom upon held at 90° C. for 1 hour is 100 ?g/cm2 or less, so that when scanned by a floating head, errors on recording and reading of information are remarkably reduced. Thus, the magnetic disk substrate can provide a magnetic disk having improved scan capability. The present invention also provides a process for manufacturing such a magnetic disk.

Abstract: During startup or shutdown of a fuel cell power plant, the electric energy generated by consumption of reactants is extracted by a storage control (200) in response to a controller (185) as current applied to an energy storage system 201 (a battery). In a boost embodiment, an inductor (205) and a diode (209) connect one terminal (156) of the stack (151) of the battery. An electronic switch connects the juncture of the inductor and the diode to both the other terminal (155) of the stack and the battery. The switch is alternately gated on and off by a signal (212) from a controller (185) until sufficient energy is transferred from the stack to the battery. In a buck environment, the switch and the inductor (205) connect one terminal (156) of the stack to the battery. A diode connects the juncture of the switch with the inductor to the other terminal (155) of the fuel cell stack and the battery.

Abstract: Apparatus and methods for regulating methanol concentration in a direct methanol fuel cell system without the need for a methanol concentration sensor. One or more operating characteristics of the fuel cell, such as the potential across the load, open circuit potential, potential at the anode proximate to the end of the fuel flow path or short circuit current of the fuel cell, are used to actively control the methanol concentration.

Abstract: A fuel cell is disclosed which is formed on a semiconductor wafer by etching channel in the wafer and forming a proton exchange membrane PEM barrier in the etched channel. The barrier divides the channel into two. A hydrogen fuel is admitted into one of the divided channels and an oxidant into the other. The hydrogen reacts with a catalyst formed on an anode electrode at the hydrogen side of the channel to release hydrogen ions (protons) which are absorbed into the PEM. The protons migrate through the PEM and recombine with return hydrogen electrons on a cathode electrode on the oxygen side of the PEM and the oxygen to form water.

Abstract: A fuel cell for production of electrical energy, such as a fuel cell, comprising a fuel chamber (1), an anode (2a), a cathode (2b), an electrolyte (3) disposed between said anode and said cathode, an oxidant chamber (4), wherein said chambers (1 and 4) enclose said anode, cathode and electrolyte, wherein a fuel flowing from the fuel chamber is oxidized at the anode, thereby producing electrical energy, wherein said electrolyte (3) is a ceramic composite electrolyte comprising at least one salt and at least one oxide in mixture.

Abstract: In a fuel cell assembly comprising a plurality of cell each including an electrolyte layer (2), a pair of diffusion electrode layers (3, 4) interposing the electrolyte layer between them, and a pair of flow distribution plates (5) for defining passages (11) for fuel and oxidant fluids that contact the diffusion electrode layers, the fuel cells are arranged on a common plane. Therefore, the vertical dimension of the fuel cell assembly can be minimized, and a fuel cell assembly of favorable electric properties can be achieved. Each flow distribution plate is typically formed with communication passages for communicating fluid passages defined on each side of the electrolyte layer at a prescribed pattern. The communication passages and through holes communicate the fluid passages in such a manner that adjacent fuels cells have opposite polarities.

Abstract: A subassembly for a stack of electrochemical cells that includes a porous metal sheet having a first face and a second face with a hydrophobic, carbonaceous gas diffusion layer disposed within the pores along the first face of the porous metal sheet. The second face of the porous metal sheet defines a flow field while that portion of the porous metal sheet filled with the gas diffusion layer forms a current collector. The subassembly may further include a metal gas barrier metallurgically bonded to the second face of the porous metal sheet to act as a gas barrier between the porous metal sheet and a second porous metal sheet having a second gas diffusion layer disposed within the pores along a face of the second porous metal sheet. Preferably, the gas diffusion layers are applied as a paste to the porous metal sheet and then dried.

Abstract: It has been difficult to keep the voltage of a polymer electrolyte fuel cell stable for a long period of time because uniform water content control over the plane of the membrane-electrode assembly is impossible. A gas diffusion electrode is produced by forming a conductive polymer layer composed of conductive particles and a polymer material on a porous material composed of carbon fiber, and forming a catalyst layer composed of platinum-carried carbon particles on the plane of the conductive polymer layer. The conductive polymer layer is composed of conductive particles different in particle size, and the content of the conductive particles having the smaller particle size is decreased from one end towards the other end of the gas diffusion electrode.

Abstract: A fuel cell includes a membrane electrode assembly and first and second separators in the form of meal plates for sandwiching the membrane electrode assembly. An anode of the membrane electrode assembly has a gas diffusion layer, and a cathode of the membrane electrode assembly has a gas diffusion layer. Each of the gas diffusion layers includes a foamed member made of metal material such as stainless steel. Resinous flow field walls are provided in the foamed member by impregnation for forming a reactant gas flow field.

Abstract: An end cap seal assembly for an electrochemical cell such as an alkaline cell is disclosed. The end cap assembly comprises a convoluted end cap which may also function as a cell terminal and an underlying insulating sealing disk. The insulating sealing disk comprises a central boss and radially extending arm terminating in a downwardly sloped elbow and upwardly sloped peripheral edge. The end cap disk has at least one vent aperture therethrough which faces the ambient environment. The insulating disk has an annular groove in its top or bottom surface, which preferably circumvents the central boss. The base of the groove defines an a rupturable membrane portion of the insulating sealing disk. The rupturable membrane is designed to rupture, preferably when the cell internal gas pressure reaches a level between about 150 and 900 psig (1034×103 and 6206×103 pascal gage) advantageously, between about 150 and 700 psig (1034×103 and 4827×103 pascal gage).

Abstract: A non-aqueous electrolyte cell having high discharge capacity, an improved capacity upkeep ratio and optimum cyclic characteristics. The non-aqueous electrolyte cell has a cell device including a strip-shaped cathode material and a strip-shaped anode material, layered and together via a separator and coiled a plural number of times, a non-aqueous electrolyte solution, and a cell can for accommodating cell device and the non-aqueous electrolyte solution. The cathode employs a cathode active material containing a compound of the olivinic structure represented by the general formula LixFe1-yMyPO4, where M is at least one selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05?x?1.2 and 0?y?0.8, with the compound being used either singly or in combination with other materials. The ratio of an inner diameter d to an outer diameter D of cell device is selected so that 0.05<d/D<0.5.

Abstract: The compositions comprise: (a) from 1 to 99% by weight of a pigment (I) having a primary particle size of from 5 nm to 100 ?m which is a solid Ia or a compound Ib which acts as cathode material in electrochemical cells or a compound Ic which acts as anode material in electrochemical cells or a mixture of the solid Ia with the compound Ib or the compound Ic, (b) from 1 to 99% by weight of a polymeric material (II) which comprises: (IIa) from 1 to 100% by weight of a polymer or copolymer (IIa) which has, as part of the chain, at the end(s) of the chain and/or laterally on the chain, reactive groups (RG) which are capable of crosslinking reactions under the action of heat and/or UV radiation, and (IIb) from 0 to 99% by weight of at least one polymer or copolymer (IIb) which is free of reactive groups RG.

Abstract: An alkaline battery includes a cathode including a nickel oxyhydroxide and an anode including zinc or zinc alloy particles.

Abstract: A battery includes an anode comprising a metal, a cathode comprising an active oxygen species, and a non-aqueous electrolyte, wherein oxidation of the metal and reduction of the active oxygen species provides the current of the battery.

Abstract: There is provided an exposure method that includes the steps of forming a phase shift mask having a desired pattern and a cyclic dummy pattern overlaid onto the desired pattern, a part of the desired pattern to be resolved by effects of the dummy pattern being thicker than the dummy pattern's line width, illuminating the phase shift mask by using illumination light having a peak near or on an optical axis in an intensity distribution to transfer the desired pattern onto the exposure plane by projecting light having passed through the phase shift mask onto the exposure plane.

Abstract: A photomask repair method including scanning an electron beam across a main surface of the photomask, thereby producing a pattern image of the photomask, identifying the position of a defective portion from the pattern image thus produced, and applying an electron beam to a region to be etched including a defective portion under an atmosphere of a gas capable of performing a chemical etching of a film material forming the photomask pattern, thereby removing a defect. In this method, the electron beam to be applied to the region to be etched is a shaped beam. The electron beam is set such that the side of the electron beam is applied in parallel to a borderline between a non-defective pattern and the defect.

Abstract: In an electrophotographic photosensitive member comprising a conductive substrate, and provided thereon a photoconductive layer containing at least an amorphous material composed chiefly of silicon atoms and, deposited on the photoconductive layer, a layer region containing an amorphous material composed chiefly of silicon atoms, which layer region contains at least partly a periodic-table Group 13 element, the content of the periodic-table Group 13 element based on the total amount of constituent atoms in the layer region deposited on the photoconductive layer has distribution having at least any two of maximum value(s) and maximum region(s) in the thickness direction of the layer region. This electrophotographic photosensitive member can be improved in charging performance, can prevent image defects due to pressure mars and can form high-quality images over a long period of time.

Abstract: A member including for example, a substrate, a charge generating layer, a charge transport layer comprising a poly(phenylsilsesquioxane), molecule, and a film forming binder.

Abstract: The present invention relates to an electrophotographic photosensitive member having a support and provided thereon a photosensitive layer. The photosensitive layer contains a high-molecular weight charge-transporting material having a specific repeating structural unit. The high-molecular weight charge-transporting material has a weight-average molecular weight Mw of 1,500 or more and an energy level of highest occupied molecular orbital, EHOMO, of from ?8.3 eV or more to ?8.0 eV or less as found by semiempirical molecular-orbital calculation. The present invention also relates to a process cartridge and an electrophotographic apparatus which have such an electrophotographic photosensitive member.

Abstract: This invention relates to a novel organophotoreceptor that includes a photoconductive layer having a) a novel charge transport compound having the formula ?where R1 is a carbazole group, a julolidine group, or a p-(N,N-disubstituted)arylamine, R2, R3, R4, R5 and R6 are, independently, an alkyl group or an aryl group, R7 and R8 are, independently, hydrogen, an alkyl group, or an aryl group, X is oxygen, sulfur, or a NR? group where R? is hydrogen, an alkyl, or an aryl group, and Y is a trivalent aryl group; (b) a charge generating compound; and wherein the at least one photoconductive layer is carried on an electrically conductive substrate.

Abstract: A toner for printing documents that are difficult to forge and that are readily easy to visually verify and methods of using and forming the toner are disclosed. The toner includes a colorant for printing an image on a surface of a document and a dye for forming a latent version of the image underneath a surface of a substrate. An image formed using the toner of the invention is readily verified by comparing the colorant-formed image and the dye-formed image.

Abstract: A chemically prepared toner for electrophotographic printers and method therefor using a unique polymeric dispersant. The chemically prepared toner includes agglomerated polymeric dispersant stabilized pigment particles, a fuser release agent, a charge control agent dispersion, and a self-stabilized essentially surfactant free latex binder. The polymeric dispersant includes at least three segments, a hydrophilic polymeric segment, a hydrophobic polymeric segment, and a protective colloid or reactive surfactant segment. The weight average molecular weight range of the dispersant ranges from about 5,000 to about 30,000, and a hydrophobicity ranging from about 10 to about 90 percent by weight. The chemically prepared toner includes agglomerated toner particles have a unimodal particles size distribution with a number average particle size (N) ranging from about 5.0 to about 8.5 microns and a volume average particle size (V) ranging from about 5.0 to about 8.5 microns.

Abstract: The present invention relates to a non-magnetic one-component toner that is characterized by containing toner particles that have a volume-average particle size of 2 to 8 ?m, a ratio of the volume-average particle size/number-average particle size of not more than 1.22, an average degree of roundness of not less than 0.92 and a Vickers hardness of not less than 13.5HV0.01 (10 g), and also concerns a non-magnetic one-component contact developing device using such a toner and an image-forming apparatus using such a developing device.

Abstract: Toner is rounded by vigorously mixing less than about 5 percent by weight of particulate silica to the total weight of a starting toner in a closed, recirculating air system. The starting toner contains at least about 4.5 percent by weight of the starting toner of a wax and additionally contains at least 5 percent by weight of the starting toner of a softening agent. The temperature during the mixing is no more than 13 degrees C. above the onset of the glass transition temperature of the starting toner. The final toner comprises rounded starting toner having particulate silica embedded during the mixing process.

Abstract: A composition containing a polymer, a crosslinker and a photo-activatable catalyst is placed on a substrate. The composition is exposed to a predetermined pattern of light, leaving an unexposed region. The light causes the polymer to become crosslinked by hydrosilylation. A solvent is used to remove the unexposed composition from the substrate, leaving the exposed pattern to become a sorbent polymer film that will absorb a predetermined chemical species when exposed to such chemical species.

Abstract: The present invention relates to a novel photoresist composition that can be developed with an aqueous alkaline solution, and is capable of being imaged at exposure wavelengths in the deep ultraviolet. The invention also relates to a process for imaging the novel photoresist as well as novel photoacid generators. The novel photoresist comprises a) a polymer containing an acid labile group, and b) a novel mixture of photoactive compounds, where the mixture comprises a lower absorbing compound selected from structure 1 and 2, and a higher absorbing compound selected from structure 4 and 5, where, R1 and R2 R5, R6, R7, R8, and R9 are defined herein; m=1–5; X? is an anion, and Ar is selected from naphthyl, anthracyl, and structure 3, where R30, R31, R32, R33, and R34 are defined herein.

Abstract: The present disclosure relates to a limited play optical storage media and a method for limiting access to data thereon. This storage media comprises: an optically transparent substrate; a reflective layer; an oxygen penetrable UV coating disposed on a side of the substrate opposite the reflective layer; and a reactive layer disposed between the UV coating and the substrate, the optical storage media having an initial percent reflectivity of about 50% or greater and a subsequent percent reflectivity of about 45% or less.

Abstract: A negative photoresist composition and a method of patterning a substrate through use of the negative photoresist composition. The composition includes: a radiation sensitive acid generator; an additive; and a resist polymer derived from at least one first monomer including a hydroxy group. The first monomer may be acidic or approximately pH neutral. The resist polymer may be further derived from a second monomer having an aqueous base soluble moiety. The additive may include one or more alicyclic structures. The acid generator is adapted to generate an acid upon exposure to radiation. The resist polymer is adapted to chemically react with the additive in the presence of the acid to generate a non-crosslinking reaction product that is insoluble in an aqueous alkaline developer solution.

Abstract: A method of fabricating a distributed feedback optical fiber laser, comprises the step of exposing an optical fiber (20) to a transverse light beam (30) to form a grating structure in a section of the optical fiber, the writing light beam being polarized in a direction not parallel to the axis of the section (10) of optical fiber (20).

Abstract: An integrated waveguide and photodetector which are evanescently coupled, and methods of making such integrated waveguide and photodetector.

Abstract: Photoresists may be formed over a structure that has been modified so as to poison a lower layer of the photoresist. Then, when the photoresist is patterned, it is only patterned down to the poisoned layer. The poisoned layer may be removed subsequently. However, because of the use of the modification process, the critical dimensions of the photoresist may be improved in some embodiments.

Abstract: Thermographic and photothermographic materials comprise a barrier layer to provide physical protection and to prevent migration of diffusible imaging components and by-products resulting from high temperature imaging and/or development. The barrier layer comprises a scavenger that is a metal hydroxide or ester. This barrier layer is capable of retarding diffusion of mobile chemicals such as organic carboxylic acids, developers, and toners.

Abstract: For a 2-dimensional periodic array of contact holes or islands, a depth-of-focus-enhancement lithographic scheme based on a combination of alternating phase-shifting mask and off-axis illumination is revealed. The scheme is achieved by choosing appropriate off-axis illumination and smaller numerical aperture such that only two diffraction orders, which are of equal distance from the pupil center, are collected in the first exposure. The image of the 2-dimensional periodic array can be formed by superposing a second exposure on the first. In the second exposure, another appropriate off-axis illumination and smaller numerical aperture is chosen such that another two diffraction orders, which are also of equal distance from the pupil center, are collected.

Abstract: An exposure method includes the steps of providing a mask that arranges a contact-hole pattern and a pattern smaller than the contact-hole pattern, and illuminating the mask using plural kinds of light so as to resolve the contact-hole pattern and restrain the smaller pattern from resolving on an object to be exposed via a projection optical system, wherein the following conditions are met A=?1.7k1+C1, 1.2?C1?1.3, 0.5?B?0.55 and B?A?0.1, 0.80???0.9 and ??A+0.1, k1=(L/?)NA, where k1 is resolving power, L is a hole diameter of the contact-hole pattern, ? is a wavelength for exposure, NA is a numerical aperture of the projection optical system, ? is a ratio of a numerical aperture of an illumination optical system to the numerical aperture of the projection optical system, A and B are distances from two orthogonal axes to a boarder of a light-shielding part in an effective light source for illumination of plural kinds of light, the light-shielding part being symmetrical with respect to the two orthogonal axes.

Abstract: The present invention relates, in general, to stem cells, and in particular, to a method of isolating stem cells and to reagents suitable for use in such a method. The invention further relates to stem cell populations isolatable in accordance with the present method.

Abstract: A self contained diagnostic test device is provided for use in the collection and detection of a biological specimen or the like. The device comprises a tubular swab and reagent dispensing cap component for receiving specimens. The reagent dispensing cap component includes barrel, reagent chamber, and results window subcomponents, and delivers one or more selected reagents to a specimen testing chamber for contacting the collected specimen, upon the rotation of the reagent chamber component.

Abstract: The invention provides cell lines which are useful for the rapid detection and production of influenza and parainfluenza viruses. In particular, the invention relates to transgenic mink lung cells which show increased sensitivity to infection by influenza A, influenza B, or parainfluenza 3 viruses, or which are capable of enhanced productivity of infectious virions. The invention is suitable for use in culturing clinical influenza and parainfluenza virus isolates and for the production of influenza and parainfluenza virus for vaccine formulations, as antigen preparations for diagnostic applications, and for screening antiviral drugs.

Abstract: Methods are provided for the rapid identification of essential or conditionally essential DNA segments in any species of haploid cell (one copy chromosome per cell) that is capable of being transformed by artificial means and is capable of undergoing DNA recombination. This system offers an enhanced means of identifying essential function genes in diploid pathogens, such as gram-negative and gram-positive bacteria.

Abstract: Disclosed herein are nucleic acid sequences that encode novel polypeptides. Also disclosed are polypeptides encoded by these nucleic acid sequences, and antibodies, which immunospecifically-bind to the polypeptide, as well as derivatives, variants, mutants, or fragments of the aforementioned polypeptide, polynucleotide, or antibody. The invention further discloses therapeutic, diagnostic and research methods for diagnosis, treatment, and prevention of disorders involving any one of these novel human nucleic acids and proteins.

Abstract: Mixtures of chemical compounds are provided having antibacterial and other utility. The mixtures are formed, preferably in solution phase, from the reaction of a purine or pyrimiding heterocyclic scaffold with a set of related chemical substituients, optionally through employment of a tether moiety. Libraries formed in accordance with the invention have utility per se and are articles of commerce. They can be used to screen for pesticides, drugs and other biologically active compounds.

Abstract: Methods for detecting and sequencing of target double-stranded nucleic acid molecules, nucleic acid probes and arrays of probes useful in these methods, and kits and systems that contain these probes are provided. The methods involve hybridizing the nucleic acids or nucleic acids which represent complementary or homologous sequences of the target to an array of nucleic acid probes. These probes include a single-stranded portion, an optional double-stranded portion and a variable sequence within the single-stranded portion. The molecular weights of the hybridized nucleic acids of the set can be determined by mass spectroscopy, and the sequence of the target determined from the molecular weights of the fragments.

Abstract: A method for isolating a polynucleotide of interest that is present in the genome of a first mycobacterium strain and/or is expressed by the first mycobacterium strain, where the polynucleotide of interest is also absent or altered in the genome of a second mycobacterium strain and/or is not expressed in the second mycobacterium. The method includes (a) contacting the genomic DNA of the first mycobacterium strain under hybridizing conditions with the DNA of a least one clone that belongs to a bacterial artificial chromosome (BAC) genomic DNA library of the second mycobacterium strain, and (b) isolating the polynucleotide of interest that does not form a hybrid with the DNA of the second mycobacterium strain. This invention further pertains to a Mycobacterium tuberculosis strain H37Rv genomic DNA library, as well as a Mycobacterium bovis BCG strain Pasteur genomic DNA library, and the recombinant BAC vectors that belong to those genomic DNA libraries.

Abstract: To measure or exert optically-induced forces on at least one particle in the focus of an optical cage, the following steps are taken: a) the focus is positioned in a microelectrode arrangement with a three-dimensional electrical field that has a field gradient which forms an electrical capture area, and the focus is at a distance from the capture are and b) the amplitude of the electrical field, the light power of the light beam forming the optical cage, and/or the distance of the capture area from the focus are varied to detect which varied field property moves the particle from the focus to the capture area or vice versa, or at least to temporarily move the particle into the capture area.

Abstract: Antibodies and methods are described for the detection and quantitation of cardiac specific troponin I in samples. Cardiac-specific troponin isoforms exist in various forms in the blood, including free and complexed forms. By selecting antibodies that are insensitive and/or sensitive to these various forms, the present invention can provide immunoassays that more accurately reflect the clinical state of an individual. These described antibodies and methods can be used for providing indicators of myocardial infarction and other cardiac pathologies.

Abstract: The present invention provides a method for screening a compound or its salt that alters the binding property between MCH or its salt and SLC-1 or its salt, characterized by using MCH or its derivative or a salt thereof and SLC-1 or its salt is useful for screening an SLC-1 agonist which can be used not only as an appetite (eating) promoting agent but also as a prophylactic/therapeutic agent for weak pains, atonic bleeding, before and after expulsion, subinvolution of uterus, cesarean section, induced abortion, galactostasis, and the like, and an SLC-1 antagonist which can be used not only as an antiobestic agents (drug), an appetite (eating) modulator, and the like, but also as a prophylactic/therapeutic agent for hyperstimulation, ankylosing uterine contractions, fetal distress, uterine rupture, cervical laceration, preterm delivery, Prader-Wili syndrome and the like.

Abstract: A novel protein, enkurin, that is preferentially expressed in sperm has been discovered. Enkurin binds to TRPCs including TRPC2-S, a protein encoded by TRPC2 that is not predicted to be a calcium channel subunit. The invention includes methods of identifying compounds that affect enkurin expression or activity, and are useful, e.g., for contraception and treatment of infertility.

Abstract: A method for identifying a Na+ channel blocker, including providing a cell containing a Na+ channel, demonstrating both a transient and a persistent current. The cell includes a potassium (K+) channel and a Na/K ATPase (Na+ pump). A fluorescent dye is disposed into the well. The fluorescent dye is sensitive to change in cell membrane potential in order to enable optical measurement of cell membrane potential. A Na+ channel blocker, to be identified, is added to the well and a stimulating current is passed through the cell in an amount sufficient to generate an action potential before and after the addition of the Na+ channel blocker. Thereafter, a change in cell membrane potential is optically measured.

Abstract: Methods, compositions and kits are disclosed. The methods are directed to determining the presence of entactogen analytes such as, for example, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-methamphetamine (MDMA), 3,4-methylenedioxy-ethylamphetamine (MDEA) and 4-hydroxy-3-methoxy-methamphetamine (HMMA). The method comprises providing in combination in a medium (i) a sample suspected of containing the compound and (ii) an antibody raised against a compound of Formula I that comprises a protein. The medium is examined for the presence a complex comprising the compound and the antibody where the presence of such as complex indicates the presence of the compound in the sample. In one aspect of the above embodiment, the combination further comprises a label conjugate of the compound Formula I.

Abstract: Novel magnetic assay methods and systems. According to a preferred embodiment, a chromatographic medium, which preferably comprises a test strip, is provided that is designed to be contacted with a test solution having activated magnetic particles such that the solution flows bilaterally thereacross. A magnetic field, generated by a magnet or electromagnet, is selectively applied to the medium which causes the charged particles to become substantially bound at a site on the medium specified by the position of the magnet, to thus form a captured line or zone. In one preferred embodiment, the magnetic field is applied at the site on the medium at which the test solution is contacted. The degree of magnetic force applied to the membrane may be selectively adjusted to vary the width or surface area of the capture line or zone.