This invention generally relates to chromatography, and more particularly to a cartridge module for simultaneously fluidically coupling at least two chromatography columns to fluid-carrying tubing within a liquid chromatography system.
Liquid chromatography (LC) is well-known in the fields of chemical separation, compound purification and chemical analysis. A central component of a liquid chromatography system is a chromatographic column. The column comprises a capillary tube that is packed with a permeable solid material that either is, itself, a chromatographic stationary phase or otherwise comprises or supports a chromatographic stationary phase. A fluid mixture comprising both a compound of interest for purification or separation as well as a chromatographic mobile phase is caused to flow through the column under pressure from an input end to an output end. Generally, the chemical properties of the stationary phase and the mobile phase are such that the degree of partitioning of the compound of interest between the mobile phase and the stationary phase is different from the degree of partitioning of other compounds within the fluid. As a result, the degree of retention or time of retention of the compound of interest within the column is different from the degree or time of retention of the other compounds, thus causing a physical separation or partial purification of the compound of interest from the other compounds.
As used herein, “liquid chromatography” (LC) means a process of selective retention of one or more components of a fluid solution as the fluid uniformly percolates through a column of a finely divided substance, or through capillary passageways. The retention results from the distribution of the components of the mixture between one or more stationary phases and the bulk fluid, (i.e., mobile phase), as this fluid moves relative to the stationary phase(s). “Liquid chromatography” includes, without limitation, reverse phase liquid chromatography (RPLC), high performance liquid chromatography (HPLC), ultra high performance liquid chromatography (UHPLC), supercritical fluid chromatography (SFC) and ion chromatography.
As used herein, the term “HPLC” or “high performance liquid chromatography” refers to liquid chromatography in which the degree of separation is increased by forcing the mobile phase under pressure through a stationary phase, typically a densely packed column.
As used herein, the term “UHPLC” or “ultra high performance liquid chromatography” refers to a liquid chromatography technique similar to HPLC except the operating pressures are higher than HPLC (e.g., about 100 MPa vs. about 40 MPa), the columns are typically smaller in diameter, and resolution can be greater.
Chromatography may be used to purify or enrich one or more analytes of a sample, prior to analysis by mass spectrometry. The chromatography step or steps are generally used to enrich one or more analytes of interest relative to one or more other components of the sample. Typically, one or more methods including, without limitation, liquid chromatography, HPLC, UHPLC, precipitation, dialysis, affinity capture, electrophoresis, or other suitable methods known in the art, are used for the purification.
Various methods have been described involving the use of HPLC for sample cleanup prior to mass spectrometry analysis. For example, see, e.g., Taylor et al., Therapeutic Drug Monitoring 22:608-12 (2000) (manual precipitation of blood samples, followed by manual C18 solid phase extraction, injection into an HPLC for chromatography on a C18 analytical column, and MS/MS analysis); and Salm et al., Clin. Therapeutics 22 Supl. B:B71-B85 (2000) (manual precipitation of blood samples, followed by manual C18 solid phase extraction, injection into an HPLC for chromatography on a C18 analytical column, and MS/MS analysis). One of skill in the art can select HPLC instruments and columns that are suitable for use in the invention. The chromatographic column typically includes a medium (i.e., a packing material) to facilitate separation of chemical moieties (i.e., fractionation). The medium may include minute particles. The particles may include a bonded surface that interacts with the various chemical moieties to facilitate separation of the chemical moieties. One suitable bonded surface is a hydrophobic bonded surface such as an alkyl bonded surface. Alkyl bonded surfaces may include C-4, C-8, or C-18 bonded alkyl groups, preferably C-18 bonded groups. The chromatographic column includes an inlet port for receiving a sample and an outlet port for discharging an effluent that includes the fractionated sample. For example, a test sample may be applied to the column at the inlet port, eluted with a solvent or solvent mixture, and discharged at the outlet port.
In another example, more than one column may be used wherein a test sample may applied to a first column (e.g., a cleanup column) at the inlet port, eluted with a solvent or solvent mixture onto a second column (e.g., an analytical column), and eluted with a solvent or solvent mixture from the second column to the outlet port. Different solvent modes may be selected for eluting the analytes. For example, liquid chromatography may be performed using a gradient mode, an isocratic mode, or a polytyptic (i.e. mixed) mode.
Complex samples, such as biologically-derived fluids, may contain a large number of compounds. Generally, a laboratory analysis will be directed to detect the presence (vs. absence) or the concentrations of a limited number of target compounds within the complex sample. Frequently, a chromatographic signature (or signatures) of the target compound (or compounds) will be masked by the elution properties of much-more-abundant matrix compounds. Therefore, it is often desirable to perform two-stage or multiple-stage chromatographic separations in order to increase analyte signal strength or to improve the ability to discriminate the analyte signal from background noise or other interferences. A first such step—i.e., a “cleanup” step—may be employed to separate certain classes or sub-sets of compounds from one another (e.g. large molecule versus small molecule, or polar versus non polar) with the fraction that may contain possible analyte substances retained and the other fraction discarded. Then, in a second chromatographic separation step—i.e., an “analytical” step—the retained fraction may be separated into particular isolated compounds. Such two-stage or multiple-stage separations may require multiple chromatographic columns, each such column uniquely optimized to perform a particular type of separation.
In operation of the system 10 (
The valve system 5 may comprise a plurality of multiple-port valves fluidically interconnected to one another, to the two pumps and to the two columns by means of various connection tubing lines. For instance, the illustrated valve system 5 comprises two multiple-port rotary valves v1, v2 such as the valves known as Rheodyne valves sold by IDEX Health & Science, 619 Oak Street Oak Harbor, Wash. USA. The valve system 5 shown in
The system 10 may further comprise an electronic controller or computer apparatus 32 under software or firmware control that is electronically connected to various other system components by electronic communication lines, schematically shown as dashed lines in
Although a conventional multiple column system, as described above, is capable of obtaining excellent analytical results, it does present a number of actual or potential issues and difficulties about which an analyst must be wary. A first potential difficulty arises from the experimental observations that the cleanup and analytical chromatography columns often need to be matched for optimal analytical results of a particular analyte from a particular type of sample. Various stationary phase materials are available for packing into each of the cleanup and analytical columns. It is often found that best results are obtained, for a given analyte and sample, with a particular combination of cleanup column and analytical column stationary phases (and mobile phases). The most-suitable matching column pair can conceivably vary from one analysis protocol to another. Thus, an analyst must take care to ensure that both the cleanup and analytical columns are appropriate for the analysis at hand and must take care to ensure that both columns are appropriately matched (and possibly replaced) when a new analysis protocol is started. A second potential issue arises from the fact that, since the multiple columns of a conventional multi-column system are not physically integrated with one another, time must be expended to separately replace both columns when a new protocol is started that requires a completely new pair of columns.
A third potential concern arises from the fact that the conventional columns do not carry on-board information on their usage history. This concern arises because chromatography columns have finite useful lifetimes. Thus, existing columns on the conventional system must be occasionally removed and replaced with fresh columns. The analyst must therefore take care to record hours used or the total number of analyses performed for each column. Although such usage history records could be maintained by an electronic controller or computer apparatus, there is a risk of such information being lost if a column is transferred from one chromatography system to another. All of the above issues provide opportunities for errors to be introduced into the analyses with possible consequent invalidation of results.
To address the above-noted issues, the present disclosure provides a modular chromatography cartridge comprising a housing having at least two chromatography columns at least partially contained therein. The columns are preferably but not necessarily affixed to the housing. Two columns in each cartridge may be matched for purposes of conducting chromatographic separations of a specific analyte (or analytes). For instance, a first column may comprise a TurboFlow® or other pre-column or cleanup column (such as a Solid Phase Extraction column or an affinity chromatography column) while a second column is an analytical column. Connection fittings protruding outside of the housing at each end of each column enable fluidic connection to a chromatograph plumbing system and/or a detector such as a mass spectrometer. The cartridge may optionally comprise heaters and temperature sensors for temperature control of one or more columns as well as optional sensors to monitor fluid flow rate, pH, etc., together with associated electronic connectors. A passive identification feature (an indicator or identifier), e.g., a barcode or RFID module may be employed to identify the cartridge and its associated chromatography methods to external apparatus/software. Further, an on-board memory module and controller chip may be used to actively record computer-readable module information, including module history information, the information transferrable through a standard interface, such as a universal serial bus (USB) port.
The connection fittings of the cartridge may provide quick connect/disconnect functionality at each end of each column housed therein, so that modules directed to analyses of different respective analytes may be rapidly interchanged. Each column connection fitting may mate with an inventive device that guides a fluid-carrying tube into the respective column end fitting such that the tube will be in contact with the column end fitting; applies a spring force to the tube which exceeds the opposing force that will be created when the column is at maximum operating pressure; and ensures that a deformable sealing member (which may be a ferrule) comes in contact with the same column end fitting, encircling the tube. Separate spring forces are applied to the tube and to the sealing member. The latter spring force ensures that a proper fluid seal is made between the tube, sealing member and column end fitting to prevent any leakage at the maximum operating pressure of the column. The positioning of the tube, sealing member, and column end fitting and the spring forces for the tube and sealing member may be provided for by a lever which provides an appropriate amount of motion and mechanical advantage such that an operator does not require a tool to insert or extract a cartridge.
In accordance with a first aspect of the invention, there is disclosed a cartridge for liquid chromatography separations comprising: a housing; and at least a first and a second chromatography column at least partially passing through the housing, each chromatography column comprising a first and a second end fitting operable to connect the chromatography to external tubing.
In accordance with a second aspect of the invention, there is disclosed a cartridge for liquid chromatography separations comprising: (a) a housing; (b) a first chromatography column at least partially passing through the housing, comprising: (i) a first and a second end fitting of the first chromatography column operable to connect the first chromatography column to external tubing; (ii) a packing material formed as a substantially uniformly distributed multiplicity of rigid, solid, porous particles having substantially uniform mean cross-section dimensions or diameters of not less than about 30 μm; and (iii) a system of interstitial channels between said particles having a total interstitial volume of not less than about 45% of the total volume of the column, wherein the particles and interstitial channels are configured such that, in operation, flow within at least a major portion of the interstitial volume is turbulent; and (c) a second chromatography column at least partially passing through the housing, comprising: (i) a first and a second end fitting of the second chromatography column operable to connect the second chromatography column to external tubing; and (ii) a packing material different from the packing material of the first chromatography column.
In a third aspect of the present invention, there is disclosed a liquid chromatography system comprising: (a) a sample source; (b) a solvent source; (c) at least one fluid pump fluidically coupled to the sample source and to the solvent source for propelling samples from the sample source and solvents from the solvent source through the liquid chromatography system; (d) at least one mixing apparatus fluidically coupled to the at least one fluid pump for mixing samples from the sample source with solvents from the solvent source; (e) a cartridge comprising: (i) a housing; and (ii) a first and a second chromatography column at least partially passing through the housing; (f) a valve system fluidically coupled to the first and second chromatography columns and to the at least one mixing apparatus; and (g) a detector fluidically coupled to the second chromatography column for detecting substances eluting from the second chromatography column, wherein the valve system is configurable so as to route fluids to the first chromatography column so as to be input thereto and so as to route fluids output from the first chromatography column to the second chromatography column so as to be input thereto.
The above noted and various other aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings, not drawn to scale, in which:
The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the described embodiments will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the embodiments and examples shown but is to be accorded the widest possible scope in accordance with the features and principles shown and described. To appreciate the features of the present invention in greater detail, please refer to
Although the conventional system 10 illustrated in
Connectors 48 are employed in order to connect the two end fittings of the first column of the cartridge 40 to fluid tubing lines 6f and 6g as well as to connect the two end fittings of the second column of the cartridge 40 to fluid tubing lines 6k and 6j. Each connector 48 may comprise a simple conventional tubing connection fitting or end fitting consisting of just a coupling nut, a tubular coupling body and a ferrule. However, in accordance with various aspects of the present teachings, the connectors 48 may comprise alternative apparatuses designed so as to not require an installation tool and so as to prevent application of a twisting motion or torque. Examples of such apparatuses are illustrated in the appended
The provision of the cartridge 40 in the system 30 (
In accordance with the above considerations, the module may comprise, in addition to the fluid connections, an electronic connector or other electrical connector that enables communication between the cartridge 40 and the controller or computer apparatus 32 by means of an electronic communication line 34f (
The cartridge 40 may include a passive identification feature (an indicator or identifier), e.g., a barcode 54 or an RFID module, etc. that may be employed to identify the cartridge and its associated chromatography methods to external apparatus/software. For instance, the system 30 may include a barcode reader (not shown) or other apparatus capable of interpreting the passive identification feature, the reader or other apparatus being electronically connected to the electronic controller or computer apparatus 32. This feature may enable system software to be able to automatically verify that the columns within an inserted cartridge are appropriate for an analysis protocol currently being conducted by the system.
The cartridge 40 may further or alternatively include various electronic control, sensing, data storage or logic components together with associated external electronic connectors. For example, the cartridge may include one or more heaters 58 in intimate contact with one or more of the contained columns so as to control temperature during a chromatographic procedure. The heater may be used, for instance, to increase temperature so as to release a sample fraction previously retained or concentrated on a stationary phase within the first column so that the sample fraction may be transferred to the second column. The cartridge may include one or more temperature sensors 60. Such sensors, if present, may work in conjunction with any on-board heaters as part of a temperature control loop to control the temperature of one or more columns. The control logic may be implemented in software of the electronic controller or computer apparatus 32 or, alternatively, may be implemented in firmware of an on-board circuitry module 52 which may comprise electronic memory or controller logic. In addition or alternatively, the circuitry module 52 may be used to actively record computer-readable data or other information pertaining to the module, including module history information, such information downloadable by or transferrable to external apparatus (such as electronic controller or computer apparatus 32) through a standard interface 50, such as a USB port. Other electrical or electronic connectors 56 may be employed to provide power to heaters, to read sensors, etc.
The cartridge 250 depicted in
As an example of a two-stage chromatographic separation, a TurboFlow® column (also sometimes know as a High Turbulence Liquid Chromatography or HTLC column) may be employed, in certain embodiments in accordance with the invention, as a “cleanup” column in a first separation step. The TurboFlow column may be employed to isolate and possibly concentrate a subset of compounds based on their size range or molecular weight range (or some other property) and then a following “analytical column” may be employed to separate the individual compounds of the isolated or concentrated subset. TurboFlow® methods and apparatus are described in detail in U.S. Pat. Nos. 5,772,874; 5,919,368 and 6,149,816, all of which are hereby incorporated by reference in their entirety as if fully set forth herein. Briefly stated, the TurboFlow® apparatus and methods include or relate to a chromatography column or body that is formed as a substantially uniformly distributed multiplicity of rigid, solid, porous particles having substantially uniform mean cross-section dimensions or diameters of not less than about 30 μm, typically 50 μm or greater up to, but not limited to, 1000 μm in certain instances. The particles are selected from a range of various sizes and shapes and are held together in a body or column as by pressure, sintering and the like so that interstitial channels having a total interstitial volume of not less than about 45% of the total volume of the column are formed between the particles. The surfaces of the particles, including the inner surfaces of the pores in the particles, are chromatographically active, as by being coated with chromatographic stationary phase layers.
Because of the nature of the particles and packing in a TurboFlow® column, the flow of the fluid mixture through the column can be at a high flow rate and is believed that, under such conditions, turbulent flow of the mixture is induced within at least a major portion of the interstitial volume, and it is postulated that such turbulent flow in fact enhances the rate of mass transfer, thus increasing the dynamic capacity of the column. From the principles of turbulence, diffusion, and chemistry, small sample molecules may be separated from a sample matrix in a TurboFlow® column. Since small molecular weight molecules diffuse faster than large molecular weight molecules, the small sample compounds diffuse into the particle pores. The turbulent flow of the mobile phase quickly flushes the large sample compounds through the column to waste before they have an opportunity to diffuse into the particle pores. Of the sample molecules that enter the pores, those that have an affinity to the chemistry inside the pores bind to the internal surface of the column particles. The small sample molecules that have a lower binding affinity quickly diffuse out of the pores and are flushed to waste. A change in mobile phase, temperature or other parameter may then cause those molecules that were bound by the TurboFlow® column to elute to the analytical column for further separation.
In various other embodiments of the invention, either a Solid Phase Extraction (SPE) column or an affinity chromatography column may be employed as a cleanup column. An SPE column may be used to eliminate or separate out certain non-analyzed or interfering chemical constituents based upon their physical or chemical tendancy to either be held within (or upon) or to pass through a stationary phase material. The interfering constituents may be either suspended or dissolved in the mobile phase. An affinity chromatography column can also to eliminate certain non-analyzed or interfering chemical constituents but, in this latter case, the elimination or separation is based on the relative tendancies of sample constituents to undergo biological interaction with the stationary phase. The biological interaction may, for instance, be a specific interaction between an antigen and an antibody or between an enzyme and the biological material upon which the enzyme specifically interacts.
In one type of experiment, the analyte or analytes of interest may be held within the cleanup column (HTLC, SPE, affinity chromatography or other) while the interfering consituents pass through the cleanup column to waste. A subsequent change of mobile phase solvent (or a change of one or more physical parameters, such as temperature) may then be used to extract the analytes of interest and direct them to the analytical column. In another type of experiment, the analyte or analytes of interest may pass through the cleanup column and then pass to the analytical column while the interfering consituents are held within the cleanup column. A different solvent or a change of one or more physical parameters may be subsequently employed to flush the separated unwanted constituents out of the cleanup column to waste. The analytical column may be a column that separates the various analytes and other constituents based upon the differing retention times within the analytical column. Optimal separation or concentration of any particular analyte may require a particular combination of cleanup and analytical column properties (e.g., chemical or physical makeup of the stationary phase).
The connector apparatus 100 shown in
The support member 116 of the apparatus 100 (
In contrast to the slidable nature of the coupling between the support member 116 and the base or housing 108, the column support member 106 is rigidly fixed in place with respect to the base or housing 108. As shown in
Returning now to the discussion of
Prior to assembly of the distal body member 110 onto the intermediate body member 114, a ferrule 122a is placed into a hollow interior portion of the intermediate body member. The purpose of the ferrule 122a is to transfer force provided by the first spring 118a through the bushing or washer 120a to the tubing 6 such that the tubing is pressed into the column end fitting 104 with sufficient force so that the pressure between the tubing and the end fitting exceeds the fluid pressure—typically 15000 psi—achieved in the column under normal operating conditions. Since the body of the tubing is generally constructed of metal, the ferrule 122a is preferably constructed of a metal—for instance, stainless steel—having a hardness that is equivalent to or greater than that of the tubing. With such choice of material, force applied to the ferrule 122a in the direction of the column 103 will tend to cause the ferrule 122a to wedge itself into the tubing wall so as create a tight metal-to-metal friction seal. In alternative embodiments, the ferrule 122a may be replaced by a shape on or integral with the tubing 6, such as a ridge, groove, ring, etc. In operation, the formed shape portion of the tubing may engage with a clamp, ring, washer, bushing etc. in contact with the first spring 118a in order to transfer spring force to the tubing 6.
In operation, the apparatus 100 also comprises a deformable sealing member 122b (which may be a ferrule), which is placed on the tubing 6 just prior to positioning the tubing end into the column end fitting 104. The purpose of the deformable sealing member or ferrule 122b is to deform, under application of force provided by the second spring 118b through the bushing or washer 120b so as to form a leak-tight seal between the tubing, end fitting and column. Accordingly, the deformable sealimg member 122b is preferably constructed of an elastic polymer material such as PEEK.
When the apparatus 100 is not in operation providing coupling between a tubing and a column, the pre-loaded spring forces are respectively taken up between the end cap 117 of the distal body member 110 and the intermediate body member 112 and between the intermediate body member and the proximal body member 114. A user may place the apparatus 100 in operation (with the tubing 6 and the ferrule 122a already in place within the apparatus and the deformable sealing member or ferrule 122b already in place on the tubing) by operating a clamping and latching mechanism 124 (comprising both a pushing mechanism and a locking mechanism) which pushes the three body members (and, consequently, also the support member 116, the tubing 6 and the hardware within the body members) in the direction of the fixed column 103 and its end fitting 104.
Once the tubing comes into contact with the end fitting, further application of force (by continued operation of the clamping and latching mechanism) causes the tubing to apply an increasing force against the first spring 118a through the ferrule 122a and the first bushing or washer 120a. Once the opposing force provided by the tubing exceeds the pre-loaded spring force on spring 118a, continued operation of the clamping and latching mechanism will cause the spring to compress, thereby enabling movement of the apparatus such that the deformable sealing member 122b comes into contact with both the proximal body member 114 and the column end fitting 104. Further operation of the clamping and latching mechanism causes both compression of the first spring 118a as well as application of an increasing opposing against the second spring 118b through the deformable sealing member 122b and the second bushing or washer 120b. Still further operation of the clamping and latching mechanism causes both springs 118a, 118b to compress with consequent increase in spring force applied to the tubing and to the sealing member. The increasing force and pressure on the sealing member 122b causes this sealing member to deform within the column end fitting 104 and around the tubing so as to create a leak-tight pressure seal.
A recess 115 in the end of the proximal body member 114 may be provided so as to provide a gap for accommodation of the deformable sealing member 122b and to guide the relative movement between the connector apparatus 100 and the column end fitting 104 during the clamping and latching procedure. The pre-compression of the springs prior to actual operation of the apparatus ensures that minimal actual movement of parts is required to achieve the required or appropriate final forces on the tubing and on the deformable sealing member.
The sealing member 125 of the alternative apparatus 145 (
A bushing or other bearing 311 may be provided within the portion of the bore or cavity 326 that receives the portion of the piston 303 so as to provide a smooth sliding surface for insertion and retraction of the piston. The movement of the piston into or partial retraction of the piston from the housing may be controlled manually by a user by means of a pushing and latching (or locking) mechanism 324. As shown the pushing and latching mechanism may comprise a hand operated lever 321 and a coupling bar 325 such that the coupling bar 325 is mechanically engaged to the lever 321 by means of a first pivot pin 322 about which an end of the coupling bar is free to rotate. A second pivot pin (not shown) similarly provides mechanical engagement between the opposite end of the coupling bar 325 and the piston 303 so that rotational motion of the lever 321 is converted into translational motion of the piston.
The piston 303 has a chamber 327 therein through which a length of tubing 306 passes. The inset drawing 330 of
In the views shown in
As may be observed from
As previously illustrated in and discussed with reference to
In accordance with the above considerations,
The connector apparatus 100a, which comprises distal body member 110a, intermediate body member 112a and proximal body member 114a, serves to couple tubing 6f to an end of the first column 42 within the cartridge 40. The connector apparatus 100b, which comprises distal body member 110b, intermediate body member 112b and proximal body member 114b, serves to couple tubing 6g to the other end of the first column. The connector apparatus 100c, which comprises distal body member 110c, intermediate body member 112c and proximal body member 114c, serves to couple input tubing 6j to the input end of the second column 44 within the cartridge 40. The connector apparatus 100d, which comprises distal body member 110d, intermediate body member 112d and proximal body member 114d, serves to couple output tubing 6k to the output end of the second column.
A first clamping mechanism 130a and a second clamping mechanism 130b are each operable by a user so as to provide the compressional clamping motions described previously. In operation of the device 150, the user will place the cartridge 40 into the device and operate both clamping mechanisms 130a, 130b, such as by rotating a lever associated with each clamping mechanism. As previously described, the positioning of the sections of tubing, ferrules or sealing members and column end fittings, as well as the application of the appropriate forces is assured by the device. As the holding force on the tube is separate from the sealing force on the deformable sealing member or ferrule, each can be set only as necessary, enabling reuse of the tube and ferrule many times more as compared to typical combination of tube and ferrule.
The system 150 illustrated in
A multiple column cartridge for chromatography systems has been disclosed. Advantageously, a multiple column cartridge in accordance with the present teachings may be employed in an automated sample preparation and analysis system, such as is disclosed in a co-pending International (PCT) application for patent titled “Automated System for Sample Preparation and Analysis” (Attorney Docket No. TFS-13AWO, Application No. PCT/US2011/058452) filed on even date herewith and published as WO 2012/058632 A1. In various embodiments, the automated sample preparation and analysis system includes a sample preparation system for preparing various samples and a sample analysis system, which may include a liquid chromatography mass spectrometer (“LCMS”) for analyzing the prepared samples according to selected analyte assays. The sample preparation system and the sample analysis system are interconnected in an automated manner A multiple column cartridge in accordance with the present teachings may assist in ease of configuration and use of such an automated system.
The discussion included in this application is intended to serve as a basic description. Although the present invention has been described in accordance with the various embodiments shown and described, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. The reader should be aware that the specific discussion may not explicitly describe all embodiments possible; many alternatives are implicit. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit, scope and essence of the invention. Neither the description nor the terminology is intended to limit the scope of the invention. All patent application publications or other publications are hereby explicitly incorporated by reference herein as if fully set forth herein.
This application is the United States National Stage Application, under 35 U.S.C. 371, of International Application PCT/US2011/058229 having an international filing date of Oct. 28, 2011, which claims the benefit of the filing date, under 35 U.S.C. 119(e), of U.S. Provisional Application 61/408,044, filed on Oct. 29, 2010.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US11/58229 | 10/28/2011 | WO | 00 | 5/2/2013 |
Number | Date | Country | |
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61408044 | Oct 2010 | US |