Abstract: A composite membrane for selectively separating (e.g., pervaporating) a first fluid (e.g., first liquid such as a high octane compound) from a mixture comprising the first fluid (e.g., first liquid such as a high octane compound) and a second fluid (e.g., second liquid such as gasoline). The composite membrane includes a porous substrate comprising opposite first and second major surfaces, and a plurality of pores. A pore-filling polymer is disposed in at least some of the pores so as to form a layer having a thickness within the porous substrate. The composite membrane further includes at least one of: (a) an ionic liquid mixed with the pore-filling polymer; or (b) an amorphous fluorochemical film disposed on the composite membrane.

Abstract: The present invention relates to a polyelectrolyte multilayer (PEM) membrane comprised of at least one bilayer, wherein the bilayer is comprised of a layer of a polymeric polycation and a layer of a polymeric polyanion. Furthermore, present invention relates to methods for the production of these PEM membranes by layer-by-layer deposition and the use of these PEM membranes for the decontamination of liquids, preferably water.

Abstract: The present invention discloses a bubble generating device for a vortex pump, includes an impeller and a stirring wheel provided coaxially with the impeller, wherein a stirring chamber is formed between the impeller and the stirring wheel, a water inlet hole is provided in the middle of the stirring wheel, and the water inlet hole is communicated with the water inlet of the vortex pump and is communicated with the stirring chamber. A stirring convex portion in the stirring chamber is selectively provided on the impeller or the stirring wheel. Correspondingly, a stirring concave portion in the stirring chamber is selectively provided on the impeller or the stirring wheel, and the stirring convex portion is inserted into the stirring concave portion. The present invention can generate smaller and more uniform bubbles and increase the surface area of the bubbles.

Abstract: Provided herein are apparatuses and systems for mixing liquids and suspensions that include vessels with structures that improve mixing while not contacting liquid delivery components. The apparatuses and systems can include a motor drive that allows speed and directional control of rotation of the vessel. The apparatuses and systems can include one or more magnets for separating magnetic beads in a suspension. Also provided are methods using said apparatuses and systems for mixing and separation processes.

Abstract: A container for two or more viscous materials is provided that contains a reservoir, one or more mixing tube(s) and frame or shield, with one or more apertures arranged within the mixing tube. The container can include a frame and a first and second polymeric film joined to a first and, respectively second surface of the frame by one or more adhesive or seal seams.

Abstract: A device for storing first and second ingredient materials, mixing the ingredient materials to form an adhesive material and dispensing the adhesive material. The device comprises: a nozzle for dispensing the third material; a first container adapted to store a first ingredient material and mix the first ingredient material with a second ingredient material; a second container disposed within the first container, and moveable between a storage position in which a second ingredient material is stored in the second container and a mixing position in which the second ingredient material is moved to the first container; a mixer that longitudinally extends into the first and second containers; a handle alternatively coupled to the mixer to mix the first and second ingredient materials or to the second container to move the second container to a dispensing position to dispense the third material.

Abstract: Method for solidifying a chemical product (10) which is in melt form, comprising the following steps: subjecting a first stream (10a) of said chemical product to a prilling stage, with production of prills (12) of varying diameter; feeding said prills (12) to a screening device, which separates them according to their diameter into at least a first fraction (13) and a second fraction (14), the average diameter of the prills of said first fraction (13) being smaller than the average diameter of the prills of said second fraction (14); subjecting a second stream (10b) of said chemical product and the first fraction (13) of prills to a granulation stage, with the production of granules (16).

Abstract: The present disclosure relates to a system and method for synthesis of condensed, nano-carbon materials to create nanoparticles. In one embodiment the system may have a source of liquid precursor, a flow control element and a shock wave generating subsystem. The flow control element is in communication with the source of the liquid precursor and creates a jet of liquid precursor. The shock wave generating subsystem drives a shock wave through at least a substantial portion of a thickness of the jet of liquid precursor to sufficiently compress the jet of liquid precursor, and to increase a pressure and a temperature of the jet of liquid precursor, to create solid state nanoparticles.

Abstract: A gas generator including an enhancer chamber provided on a first end of a cylindrical housing and including an igniter therein, a diffuser portion formed with a gas discharge port on a second end, a combustion chamber provided between the diffuser portion and the enhancer chamber, the enhancer chamber being an internal space which is axially sandwiched between the igniter and a cup-shaped partition wall, the internal space accommodating therein an enhancing agent, the cup-shaped partition wall including a peripheral wall provided with a peripheral wall body with a plurality of nozzles and an annular portion expanding outwardly from the peripheral wall body, an outer surface of the annular portion abutting against an inner wall surface of the cylindrical housing, a cylindrical gap being formed between the peripheral wall body and the inner wall surface, the nozzles being disposed to face the cylindrical gap, and the cylindrical gap being devoid of the gas generating agent therein.

Abstract: The disclosure is directed to the use of an upflow reactor for producing a dihydroxy compound, to a method for producing a dihydroxy compound, and to a method for manufacturing polycarbonate. The upflow reactor for producing a dihydroxy compound of the disclosure comprises: a vessel; a catalyst bed disposed in said vessel; a distributor in fluid communication with an inlet through which reactants are introduced to said distributor, said distributor being disposed at a lower end of said vessel and comprising distributor perforation(s) disposed in said distributor, at least part of which distributor perforations are in a direction facing away from said catalyst bed; and a collector through which said product dihydroxy compound is removed, said collector being disposed at an upper end of said vessel.

Abstract: A catalytic bed for a chemical reactor, said catalytic bed having an annular-cylindrical geometry and comprising at least one collector made with a gas-permeable cylindrical wall, containing at least a first catalyst and a second catalyst, wherein the second catalyst has a finer particle size than the first catalyst, and wherein the first catalyst forms a layer of catalyst adjacent to and in contact with said collector.

Abstract: Internally reinforced aerogels, articles of manufacture and uses thereof are described. An internally reinforced aerogel includes an aerogel having a support at least partially penetrating the aerogel and having the aerogel penetrating the porous structure of the support.

Abstract: A method for producing molecular assemblies of an amphiphilic block polymer includes applying a polymer solution in a layered shape on a planar base member, the polymer solution including an amphiphilic block polymer and a solvent, the amphiphilic block polymer having a hydrophilic block chain including 20 or more sarcosine units and a hydrophobic block chain including 10 or more lactic acid units, forming a polymer film on the planar base member by removing the solvent from a coated layer of the polymer solution, and obtaining molecular assemblies by bringing the polymer film into contact with a water-based liquid. The planar base member is a flexible long film.

Abstract: The present invention relates to a method for preparing solid microcapsules, comprising the following steps a) adding, with stirring, a composition C1 to a polymeric composition C2 comprising at least one aliphatic or aromatic ester or polyester, additionally bearing at least one function selected from the group consisting of acrylate, methacrylate, vinyl ether, N-vinyl ether, epoxy, siloxane, amine, lactone, phosphate and carboxylate functions and mixtures thereof, whereby an emulsion (E1) is obtained comprising droplets of composition C1 dispersed in a composition C2; b) adding, with stirring, the emulsion (E1) to a composition C3 whereby a double emulsion (E2) is obtained comprising droplets dispersed in the composition C3; c) applying shear to the emulsion (E2) whereby a double emulsion (E3) is obtained comprising droplets of controlled size dispersed in the composition C3; and d) polymerizing the composition C2, whereby solid microcapsules dispersed in the composition C3 are obtained.

Abstract: A propulsion element including a catalyzing reactor is disclosed. The catalyzing reactor comprises a reactor entrance and a reactor exit and an internal structure arranged for flowing a reacting medium through the reactor from the reactor entrance to the reactor exit. The reactor structure comprising at least one thin walled reactor channel arranged between the entrance and the exit of the reactor. The channel having a channel wall that includes a catalyst and that defines a flow path, in which channel in use, a catalyzed exothermic reaction takes place in the medium as it flows along the flow path. The at least one channel is looped to have a portion of its flow path that is downstream with respect to the reactor entrance in heat exchanging contact with a portion of a flow path that is that is more upstream with respect to the reactor entrance, so as to transfer heat between a downstream portion of the reacting medium to an upstream portion thereof.

Abstract: Devices and methods are provided for spotting an array with fluid. Arrays produced by such methods are also provided. In one aspect of the invention, a spotter device for spotting a plurality of fluids into an array is described, the spotter device comprising a plurality of reservoirs provided in a first configuration, each reservoir holding its respective fluid, a print head having a plurality of positions provided in a second configuration, the second configuration being different from the first configuration, a plurality of tubes, each tube configured to provide fluid communication from a reservoir at a first end of the tube to a position in the print head at the second end of the tube, and a pump for pumping fluid through the tubes from the reservoir to the print head.

Abstract: The present invention provides methods, compositions, and systems for distributing single polymerase molecules into array regions. In particular, the methods, compositions, and systems of the present invention result in a distribution of single polymerase molecules into array regions at a percentage that is larger than the percentage expected to be occupied under a Poisson distribution.

Abstract: A method of processing a liquid by an alternating electromagnetic field includes: generating DC pulses by a pulse generator; and applying the DC pulses to a parallel oscillating circuit connected in parallel to the pulse generator. The parallel oscillating circuit includes an inductor connected in parallel to a capacitor. In response to the DC pulses, self-oscillations arise in the parallel oscillating circuit, the self-oscillations producing an alternating current in the inductor; and the inductor generates the alternating electromagnetic field for processing the liquid.

Abstract: The present disclosure relates to a method for separating a carbon isotope and a method for concentrating a carbon isotope using the same, the method for separating a carbon isotope including: cooling a formaldehyde gas to a temperature of from 190K to 250K; and obtaining a mixed gas and residual formaldehyde by photodissociating the cooled formaldehyde gas, the mixed gas including carbon dioxide containing a carbon isotope and hydrogen.

Abstract: Described herein is a modification unit (37) for the continuous, pathogen reduced processing of a guidance molecule e.g. a conjugate of a peptide or a protein or a nucleic acid and a linker comprising the following components: at least one reservoir containing the guidance molecule in buffer solution (1) and/or at least one inlet for a product stream containing the guidance molecule in buffer solution, at least one reservoir containing the linker in solution (2), at least one mixing device (3), at least two valves (7, 8), one for dosage of the guidance molecule and one for dosage of the linker molecule at least one outlet for the product stream comprising the guidance molecule-linker complexes and/or a reservoir for taking up the guidance molecule-linker complexes (5) further comprising at least one residence time device ensuring a defined residence time, i.e. ensuring that after mixing the guidance molecules and the linker molecules always spend a similar amount of time in a continuous process.

Abstract: Compositions for regeneration of spent dialysis fluid are disclosed. The compositions include a sorbent comprising a titanium-glyoxal complex. Sorbent cartridges comprising the sorbents, and methods and systems for using the cartridges in dialysis also are disclosed.

Abstract: The present disclosure relates to an adsorbent composition for reducing impurities of heat transfer fluids and a process for the preparation of the same. The adsorbent composition comprises a layered double hydroxide in an amount in the range of 15 to 70 wt % of the total mass of the composition; alumina in an amount in the range of 30 to 85 wt % of the total mass of the composition; and optionally activated bauxite in an amount in the range of 15 to 50 wt % of the total mass of the composition. The present disclosure provides economical and eco-friendly adsorbent composition having feed processing capacity in the range of 58 to 600 gm/gm.

Abstract: Methods of preparing a mercury sorbent material are provided. The methods comprise making a copper/clay mixture by admixing a dry clay and a dry copper source; making a sulfur/clay mixture by admixing a dry clay and a dry sulfur source; admixing the copper/clay mixture and the sulfur/clay mixture, to form a mercury sorbent premixture; and shearing the mercury sorbent pre-mixture to form the mercury sorbent material. Various substrates may be used with or instead of the clay, and various additives may be added to the copper, sulfur, clay, or mixture thereof.

Abstract: Disclosed herein are lithiated cyclodextrin metal organic frameworks and method of making and using the same. A metal organic framework comprising a coordinated network of repeating units extending in three dimensions, wherein the repeating unit comprises a cyclodextrin, a first coordinating metal cation, and a second coordinating metal cation.

Abstract: Adsorbent polymeric structures are described. These adsorbent polymeric structures are capable of separating non-polar hydrocarbons, such as crude oil or diesel fuel, from polar liquids, such as water. The adsorbent polymeric structures may include acid grafted graphene and at least one styrene. A method of preparing an adsorbent polymeric structure may include mixing graphene and at least one acid catalyst in a polar liquid in the presence of at least one alcohol to form an acid grafted graphene via an esterification reaction; and the acid grafted graphene and at least one styrene monomer are introduced to water in the presence of an initiator to form the adsorbent polymeric structure according to any of the previously-described embodiments via an emulsion polymerization reaction. Moreover, the adsorbent polymeric structures may be incorporated into methods of fluidly separating at least one non-polar hydrocarbon from a polar liquid.

Abstract: The present invention relates to a method for preparing superabsorbent polymer. The method for preparing superabsorbent polymer according to the present invention enables providing superabsorbent polymer having excellent absorption ratio, absorption speed and permeability.

Abstract: The present disclosure relates to a preparation method for a super absorbent polymer sheet and a super absorbent polymer sheet prepared therefrom. According to the preparation method of the present disclosure, a porous super absorbent polymer sheet can be prepared by a simplified process.

Abstract: Disclosed is a ruthenium-based catalyst for hydrogen production from ammonia decomposition, comprising an active component, a promoter and a carrier, wherein the active component is ruthenium, the promoter is cesium and/or potassium, and the carrier comprises magnesium oxide, an activated carbon, cerium oxide, molybdenum oxide, tungsten oxide, barium oxide and potassium oxide. The present invention further discloses a preparation method and application of the aforementioned ruthenium-based catalyst for hydrogen production from ammonia decomposition. Compared with the prior art, the ruthenium-based catalyst for hydrogen production from ammonia decomposition provided by the present invention is low in preparation cost and simple in process, and has high catalytic activity at low temperature and good heat resistance.

Abstract: A catalysator element comprising a mixed metal oxide compound for conversion of nitrogen oxides (NOx). Methods for the preparation of the present mixed metal oxide compound for use in the present catalysator element and to exhaust systems for a combustion engine comprising the present catalysator element for conversion of (NOx) in exhaust gasses. Specifically, a catalysator element for conversion of nitrogen oxides (NOx) comprises a solid support coated with a calcined mixed metal oxide hydrotalcite-like compound. The calcined mixed metal oxide hydrotalcite-like compound comprises at least one bivalent metal (M2+) and at least one trivalent metal (M3+).

Abstract: Provided are an intermetallic compound having high stability and high activity, and a catalyst using the same. A hydrogen storage/release material containing an intermetallic compound represented by formula (1): RTX . . . (1) wherein R represents a lanthanoid element, T represents a transition metal in period 4 or period 5 in the periodic table, and X represents Si, Al or Ge.

Abstract: A carrier powder is thermodynamically stable and conductivity can be easily provided thereto. A carrier powder includes an aggregate of carrier fine particles; wherein: the carrier fine particles include a chained portion structured by fusion bonding a plurality of crystallites into a chain; the carrier fine particles contain titanium oxide; and a ratio of anatase phase/rutile phase of the titanium oxide of the carrier powder is 0.2 or lower.

Abstract: The present invention discloses a low-platinum catalyst based on nitride nanoparticles and a preparation method thereof. A component of an active metal of the catalyst directly clades on a surface of nitride particles or a surface of nitride particles loaded on a carbon support in an ultrathin atomic layer form. Preparation steps including: preparing a transition-metal ammonia complex first, nitriding the obtained ammonia complex solid under an atmosphere of ammonia gas to obtain nitride nanoparticles; loading the nitride nanoparticles on a surface of a working electrode, depositing an active component on a surface of the nitride nanoparticles by pulsed deposition, to obtain the low platinum loading catalyst using a nitride as a substrate. The catalyst may be used as an anode or a cathode catalyst of a low temperature fuel cell, has very high catalytic activity and stability, can greatly reduce a usage amount of a precious metal in the fuel cell, and greatly reduces a cost of the fuel cell.

Abstract: A method comprising a) contacting a solvent, a carboxylic acid, and a peroxide-containing compound to form an acidic mixture wherein a weight ratio of solvent to carboxylic acid in the acidic mixture is from about 1:1 to about 100:1; b) contacting a titanium-containing compound and the acidic mixture to form a solubilized titanium mixture wherein an equivalent molar ratio of titanium-containing compound to carboxylic acid in the solubilized titanium mixture is from about 1:1 to about 1:4 and an equivalent molar ratio of titanium-containing compound to peroxide-containing compound in the solubilized titanium mixture is from about 1:1 to about 1:20; and c) contacting a chromium-silica support comprising from about 0.1 wt. % to about 20 wt. % water and the solubilized titanium mixture to form an addition product and drying the addition product by heating to a temperature in a range of from about 50° C. to about 150° C. and maintaining the temperature in the range of from about 50° C. to about 150° C.

Abstract: A carrier-nanoparticle complex including: a carbon carrier; a polymer layer provided on a surface of the carbon carrier; and metal nanoparticles provided on the polymer layer, a catalyst including the same, an electrochemical cell or a fuel cell including the catalyst, and a method for preparing the same.

Abstract: Compositions comprising metal organic frameworks and related methods and uses are generally provided, including use in selective carbonylation of heterocyclic compounds.

Abstract: The invention relates to ylide-functionalized phosphane ligands, the production of same and use in transition metal compounds, as well as the use of same as catalysts in organic reactions.

Abstract: The present invention discloses a method and system of recovering elemental sulfur and regenerating the catalyst for a sulfur-deposited catalyst, including immersing the sulfur-deposited catalyst in the ammonium sulfide solution, the leaching reaction under normal pressure and temperature, replacing the ammonium sulfide solution and immersing again for extraction for the same time; collecting the leachate of the two steps, conducting gas stripping of the elemental sulfur by adopting the high-temperature nitrogen gas, condensing the tail gas of gas stripping, subjecting to a purification treatment and then discharging, with the liquor condensate being the ammonium sulfide solution. Finally, the solid in the leachate is filtered, washed and dried after the gas stripping to obtain the elemental sulfur; and the washing and drying of catalysts that has been subjected to the two times of immersion and extraction obtain the regenerated catalysts.

Abstract: A method for preparing an anion adsorbent may be provided, which comprises the steps of: mixing at least two metal salts with each other, thereby forming a stack structure in which cationic compound layers and anionic compound layers containing anions and water of crystallization are alternately stacked on one another; performing a first heat treatment on the stack structure to expand between the cationic compound layers, thereby preparing a preliminary anion adsorbent; and performing a second heat treatment on the preliminary anion adsorbent to remove the anions and the water of crystallization from the anionic compound layers while allowing at least one of the anions to remain, thereby preparing the anion adsorbent.

Abstract: Methods, sorbent cartridges and cleaning devices are disclosed for refurbishing sorbent materials. In one implementation among multiple implementations, a medical fluid delivery method includes: providing a sorbent cartridge including H+ZP within a casing for a treatment; and after the treatment, refurbishing the H+ZP while maintained within the casing via (i) regenerating the non-disinfected H+ZP by flowing an acid solution through the casing, (ii) rinsing the regenerated H+ZP while maintained within the casing, (iii) disinfecting the regenerated and rinsed H+ZP by flowing a disinfecting agent through the casing, and (iv) rinsing the regenerated and disinfected H+ZP while maintained within the casing. Multiple batch sorbent refurbishing implementations are also disclosed.

Abstract: Embodiments are directed towards methods and systems of depositing a uniform test-pathogen mixture onto a test article for testing the sterilization efficacy of an electromagnetic radiation or other sterilization process. The system includes a holding mechanism configured to removably secure the test article to the system. The system also includes a test-pathogen dispenser configured to uniformly deposit the test-pathogen mixture onto a reference surface of the test article. The system is structured so that at least one of the test article and the test-pathogen dispenser moves relative to the other. A plurality of test-pathogen mixture droplets or lines is deposited onto the reference surface in a predetermined test-pathogen pattern, such as, for example, a plurality of rows and columns of droplets. A distance from a dispenser tip of the test-pathogen dispenser to the reference surface of the test article may be determined to help maintain consistency between test-pathogen mixture droplets or lines.

Abstract: Disclosed herein are devices, apparatus, systems, methods and kits for collecting and storing a fluid sample from a subject. A device for collecting the fluid sample can include a housing comprising a recess having an opening, a vacuum chamber in the housing and in fluidic communication with the recess, and one or more piercing elements that are extendable through the opening to penetrate skin of the subject. The vacuum chamber can be configured for having a vacuum that draws the skin into the recess. The recess can be configured having a size or shape that enables an increased volume of the fluid sample to be accumulated in the skin drawn into the recess.

Abstract: Flow cells systems and corresponding methods are provided. The flow cells systems may include a socket comprising a base portion, a plurality of electrical contacts and a cover portion that includes a first port. The flow cells systems may also include a flow cell device secured within an enclosure of the socket. The flow cell device may comprise a frameless light detection device comprising a base wafer portion, a plurality of dielectric layers, a reaction structure, a plurality of light guides, a plurality of light sensors, and device circuitry electrically coupled to the light sensors. The flow cell device may also comprise a lid forming a flow channel over the reaction structure that includes a second port in communication with the flow channel and the first port of the socket. The device circuity of the light detection device may be electrically coupled to the electrical contacts of the socket.

Abstract: A mechanically-actuated vacuum-controlled fluid collection system includes a mechanically-actuated vacuum controller (MA VC) to draw fluid into a chamber through the opening to the chamber. The system may include a releasable seal to seal the opening, and the MAVC may include a spring-loaded plunger to create a vacuum within the chamber when sealed. The system includes multiple fluid chambers, and may further include a single actuator or multiple corresponding actuators. The system may be configured to add a pre-loadable reagent to fluid drawn into the one or more chambers, and may be configured to add the reagent in proportion to a volume of the fluid. The system may be controllable to release collected fluid to another device, such as for assay and/or transport. The system may be configured to draw a liquid biological sample such as urine, and may include a fluid interface to draw fluid from a biological sample container.

Abstract: Disclosed herein are devices, apparatus, systems, methods and kits for collecting and storing a fluid sample from a subject. A device for collecting the fluid sample can include a housing comprising a recess having an opening, a vacuum chamber in the housing and in fluidic communication with the recess, and one or more piercing elements that are extendable through the opening to penetrate skin of the subject. The vacuum chamber can be configured for having a vacuum that draws the skin into the recess. The recess can be configured having a size or shape that enables an increased volume of the fluid sample to be accumulated in the skin drawn into the recess.

Abstract: This patent application describes an integrated apparatus for processing polynucleotide-containing samples, and for providing a diagnostic result thereon. The apparatus is configured to receive a microfluidic cartridge that contains reagents and a network for processing a sample. Also described are methods of using the apparatus.

Abstract: An embodiment of a system includes a compartment-generating device, a compartment detector, and electronic computing circuitry. The device is configured to generate compartments of a digital assay, at least one of the compartments having a respective volume that is different from a respective volume of each of at least another one of the compartments. The detector is configured to determine a number of the compartments each having a respective number of a target that is greater than a threshold number of the target. And the electronic circuitry is configured to determine a bulk concentration of the target in a source of the sample in response to the determined number of compartments. Because such a system can be configured to estimate a bulk concentration of a target in a source from a polydisperse digital assay, the system can be portable, and lower-cost and faster, than conventional systems.

Abstract: A microtiter plate mixing control system is disclosed. The system includes a frame, a suspension attached to the frame, and a magnetically responsive horizontal platform supported on the frame by the suspension. A solenoid is adjacent the platform for moving the platform on the suspension. A proximity sensor is adjacent the platform for determining the position of the platform with respect to the frame. A controller is in communication with the proximity sensor and the solenoid for driving the solenoid and moving the platform in response to the proximity sensor.

Abstract: Disclosed are a gene detection chip, in which a gene detection channel is formed by an injection port, a microchannel, a reaction cell, and an exit port. The surface of the reaction cell has an aptamer, and the aptamer is modified with a fluorescent label. A detection method and a manufacturing method of the gene detection chip and a microfluidic control chip system are also disclosed. Upon a gene detection being performed, the fluorescent light of the fluorescent label is firstly quenched, and then a sample solution is introduced into the reaction cell through the injection port. If the sample solution has target gene, the target gene will hybridize and combine with the aptamer on the surface of the reaction cell, so as to recover the fluorescent light; if the sample solution does not have the target gene, the fluorescent light stays in the quenched state.

Abstract: Techniques regarding one or more structures that can facilitate automated, multi-stage processing of one or more nanofluidic chips are provided. For example, one or more embodiments described herein can comprise a system, which can comprise a roller positioned adjacent to a microfluidic card comprising a plurality of fluid reservoirs in fluid communication with a plurality of nanofluidic chips. An arrangement of the plurality of nanofluidic chips on the microfluidic card can defines a processing sequence driven by a translocation of the roller across the microfluidic card.

Abstract: A microfluidic device (10) comprising: a main body; at least one source reservoir and at least one collection reservoir (18,20); at least one fluid channel (12) for channelling a fluid comprising a compound from the at least one source reservoir (18) to the at least one collection reservoir (20); a plurality of chambers (13) for holding cells, wherein the plurality of chambers (13) are formed underneath and open to the fluid channel (12), wherein a fluid flow is generated through the at least one fluid channel (12) by a difference in hydrostatic pressure between fluid in the at least one source reservoir (18) and fluid the at least one collection reservoir (20) such that the fluid flow provides a compound concentration gradient across the plurality of chambers (13) and wherein the at least one collection reservoir (20) has an overflow opening (32) to substantially maintain a level of hydrostatic pressure in the at least one collection reservoir (20).