Abstract: Methods for making microporous polyvinylidene fluoride (PVDF) membranes from vinylidene fluoride polymers and the products produced. The PVDF microporous membranes have a significantly faster flow rate at a given pore size as compared to equally-sized microporous membranes made by conventional procedures. The PVDF microporous membranes also have significantly smaller pore sizes than conventional microporous PVDF membranes. The present membranes have unique macrostructural features responsible, in part, for their unique functional properties. The process includes dissolving the polymer in a liquid that includes a solvent and a co-solvent for the polymer. The dissolution of the polymer can be at temperatures ranging from about 20.degree. C. to about 50.degree. C. while the formation of the microporous membrane can be at temperatures ranging from about -10.degree. C. to 50.degree. C.

Abstract: A mailing label and system and method for preparing the same is provided. The mailing labels are provided on a continuous perforated strip, where the perforations define unitary fields of labels, including at least a label for an intended recipient's address and a label for bearing a postal service approved postage indicia, to be used on a single item to be mailed. The strip is adapted for use with a computer driven printer capable of printing the recipient's address, the postage indicia and other data relating to the item to be mailed on the labels within a given unitary field. The system and method according to the invention provide for the ability to prepare the aforementioned mailing labels by effectively combining the functions of a postage meter with a system for preparing mailing labels.

Abstract: A filter cartridge that includes a track etched membrane sealed therein in a leak-free manner, and a method for making the cartridge. The filter cartridge has a bubble point that is at least 50% of the bubble point of the track etched membrane. In one embodiment, the method includes disposing the track etched membrane below a heat source and orienting the membrane so that it melts back on itself, and then allowing the membrane to cool to form a leak-free seal.

Abstract: A laboratory research tool for conducting a variety of procedures including cell and tissue culture techniques includes a multi-well cluster plate, a filter plate that has one or more filter wells that extend into the wells of the cluster plate, a cover and a reservoir that can be used with auxiliary equipment designed for use with standard 96-well format cluster plates. The system allows multiple tissue samples to be grown and manipulated simultaneously.

Abstract: The present invention features hydrophobic articles of manufacture having a composition comprising a plastic and a fluoropolymer. The plastic-fluoropolymer composition is resistant to irradiation allowing the article to maintain hydrophobic properties through standard irradiation processes.

Abstract: A laboratory article, and in particular a cluster plate is provided including a plurality of wells supported by a structural framework including a peripheral wall. At locations in the structural framework a plurality of protrusions are provided so as to support the cluster plate on a support surface, such as a benchtop, in a point-to-point manner. Such point-to-point support allows the article to be moved across the support surface without the generation of unpleasant audible vibrations. According to a preferred embodiment, a cluster plate having protrusions extending from the lower edge of a peripheral wall is provided.

Abstract: The present invention features methods and apparatus for forming a plurality of tracks in a foil or film with high-energy charged particles by forming layers.

Abstract: Microporous membranes having supporting structures are disclosed. A microporous filtration membrane made of a polymeric material has an integral support, both the support and the membrane having substantially identical chemical composition. Preferred supported membranes of the present invention are made of polyvinylidene fluoride. At least part of the support is bonded to the surrounding microporous membrane to provide rigidity and chemical inertness. Methods of forming the supported microporous membranes are described, including a method that results in microporous membranes having unique structural and functional characteristics.

Abstract: A tissue or cell growth device is described for placement within a well of a cluster dish. The device has a cell or tissue retention element detachably attached to a hanger. The hanger preferably has openings allowing access to the well without removal of the member and is capable of positioning the cell or tissue retention element a preselected distance relative to the hanger. Also described are various embodiments of the device having differently shaped hangers and the combination of the device and a cluster dish.

Abstract: Apparatus for growing tissue cultures in vitro, which permits a concentration gradient of nutrients to develop through a permeable membrane to which a sample of tissue is attached. The permeable membrane is attached to the bottom end of a tubular support that in turn hangs by a flange connected to its upper end on the top of a well containing the nutrients. Typically, the well is part of a tissue culture cluster dish. The flange of the support positions the support and membrane centrally in the well so as to avoid capillary action in the space between the well and support. The configuration of the support and its cooperation with the lid of the cluster dish also prevents the support and membrane from floating in the nutrient solution in the well. Openings in the support provide access for a pipette to add and withdraw fluid from the space between the well and membrane support and from the space below the membrane.

Abstract: A tissue or cell growth device is described for placement within a well of a cluster dish. The device has a cell or tissue retention element detachably attached to a hanger. The hanger preferably has openings allowing access to the well without removal of the member and is capable of positioning the cell or tissue retention element a preselected distance relative to the hanger. Also described are various embodiments of the device having differently shaped hangers and the combination of the device and a cluster dish.

Abstract: A multi-well test plate which includes a base and a plurality of well strips. The well strips are removable from the base and the individual wells of each strip are separable. The wells in each strip are joined by T-shaped connecting members which hold the wells in a flat linear array when the well strips are either held in or removed from the base and the T-shaped members are readily severable to permit easy separation of individual wells. The bottom wall of each well is a microporous membrane.

Abstract: A hand-held, manually operated pipetter having a variable volume controlled by a rotating spindle and adjusting screw that control the position of a stop which limits the upper end of the stroke of the pipetter piston. The lower end of the stroke is controlled by a movable stop urged to a first position by a blow-out spring which may be overcome with additional force applied to the pipetter piston when the lower stop is engaged. The pipetter also includes a stripper which surrounds the tip holder and which is actuated by a rod movable in the body of the pipetter along a path parallel to the path of the pipetter piston. The pipetter piston and the stripper rod are controlled by separate actuators which may readily be engaged by the thumb of the hand which holds the body of the device.

Abstract: A multi-well test plate which includes a base and a plurality of well strips. The well strips are removable from the base and the individual wells of each strip are separable. The wells in each strip are joined by T-shaped connecting members which hold the wells in a flat linear array when the well strips are either held in or removed from the base and the T-shaped members are readily severable to permit easy separation of individual wells.

Abstract: Apparatus for growing tissue cultures in vitro, which permits a concentration gradient of nutrients to develop through a permeable membrane to which a sample of tissue is attached. The permeable membrane is attached to the bottom end of a tubular support that in turn hangs by a flange connected to its upper end on the top of a well containing the nutrients. Typically, the well is part of a tissue culture cluster dish. The flange of the support positions the support and membrane centrally in the well so as to avoid capillary action in the space between the well and support. The configuration of the support and its cooperation with the lid of the cluster dish also prevents the support and membrane from floating in the nutrient solution in the well. Openings in the support provide access for a pipette to add and withdraw fluid from the space between the well and membrane support and from the space below the membrane.

Abstract: A filter strip and composite assemblies for filtering microliter quantities of fluids. A linear array of wells having open top and bottom ends are connected by frangible webs in spaced-apart relation with discrete filter membranes closing the bottom ends of each well. Tabs are provided on the ends of the filter strip for holding the same and supporting the strip in a rectangular holder having alpha-numeric designations for identifying each well in a plurality of such filter strips contained within the holder. The filter strip may be used in a vacuum manifold for applying a pressure differential across the filter membrane and directing the filtrate into an aligned aperture of a closed bottom well of an array of wells held within the manifold. Alternatively, the filter strip may be used with a transfer plate for directing the filtrate from each well of the filter strip to an aligned well of a closed bottom array of wells.

Abstract: A tissue culture flask having a flat bottom wall with optical properties on the inner surface of which cells are grown. A top wall opposite the bottom wall has a large opening therethrough which provides access to the growing surface for the removal of cells growing on the surface. The opening is closed by a flexible transparent film which is sealed to the top wall and which may be peeled off the top wall to provide access to the flask interior.

Abstract: A filtration system for handling an array of filter wells which are open at the top and closed by a filter membrane at the bottom. The system includes a manifold chamber defined by side and bottom walls and having a support for the wells which carries the filter membranes above the bottom walls so that filtrate may be drawn through the membranes. A vacuum fitting is connected to the chamber so that a low pressure source may be applied thereto, and a sealing sheet extends over the wells and having holes aligned with the open tops of the wells so that when the low pressure is applied to the chamber, filtrate may be drawn through the membrane.

Abstract: A filter strip and composite assemblies for filtering microliter quantities of fluids wherein a linear array of wells having open top and bottom ends are connected by frangible webs in spaced-apart relation with discrete filter membranes closing the bottom ends of each well. Tabs are provided on the ends of the filter strip for holding the same and supporting the strip in a rectangular holder having alphanumeric designations for identifying each well in a plurality of such filter strips contained within the holder. The filter strip may be used in a vacuum manifold for applying a pressure differential across the filter membrane and directing the filtrate into an aligned aperture of a closed bottom well of an array of wells held within the manifold. Alternatively, the filter strip may be used with a transfer plate for directing the filtrate from each well of the filter strip to an aligned well of a closed bottom array of wells.