FLUID TRANSFER MECHANISM FOR NEEDLE-FREE INJECTION DEVICE

Abstract

An injection device for use with a cartridge facilities a transfer of fluid from the cartridge into an injection bore.

Claims

1. An injection device for use with a cartridge containing an injectate, the injection device comprising: a housing including: an end wall at a distal end of the housing; an inner wall extending in a direction from a proximal end of the housing toward the distal end, the inner wall separating a first chamber from a second chamber in the housing, the first chamber extending along a first axis and the second chamber extending along a second axis, where an angle between the first axis and the second axis is nonzero; a first opening disposed in the end wall and in fluid communication with the first chamber; a second opening in fluid communication with the second chamber; a coupler disposed in the first chamber for coupling to the cartridge; and wherein the first opening and the second opening are in fluid communication via a channel for transfer of fluid between the first chamber and the second chamber.

2. The injection device of claim 1 wherein the angle between the first axis and the second axis is an acute angle.

3. The injection device of claim 1 wherein the angle between the first axis and the second axis is an obtuse angle.

4. The injection device of claim 1 wherein the angle between the first axis and the second axis is equal to 180.

5. The injection device of claim 1 wherein the second opening is disposed in the end wall.

6. The injection device of claim 2 further comprising a covering attached to an outer surface of the distal end wall, wherein the channel is formed between the outer surface of the distal end wall and the covering.

7. The injection device of claim 6 wherein the covering includes a removable foil.

8. The injection device of claim 6 wherein the covering includes a membrane.

9. The injection device of claim 8 wherein the membrane is gas permeable and liquid impermeable.

10. The injection device of claim 6 wherein the covering includes a removable cap.

11. The injection device of claim 2 further comprising a removable cap attached to the distal end of the body, wherein at least a portion of the channel is fully formed within the cap.

12. The injection device of claim 11 wherein the cap includes a third opening disposed at a first end of the portion of the channel and a fourth opening disposed at a second end of the portion of the channel, the third opening being aligned with the first opening and the fourth opening being aligned with the second opening.

13. The injection device of claim 1 wherein the coupler includes a needle in fluid communication with the channel.

14. The injection device of claim 13 further comprising a piercable member configured to receive the needle and prevent fluid from passing through the channel in a direction from the second chamber to the first chamber.

15. The injection device of claim 1 wherein the coupler includes a Luer connector in fluid communication with the channel.

16. The injection device of claim 1 wherein the coupler includes a pierceable membrane in fluid communication with the channel.

17. The injection device of claim 1 further comprising a plunger disposed in the second chamber.

18. The injection device of claim 1 further comprising a check valve configured to prevent fluid from passing through the channel in a direction from the second chamber to the first chamber.

19. The injection device of claim 1 wherein a maximum rate of flow of fluid through the channel is limited to be less than a maximum rate of flow of fluid through the second opening.

20. The injection device of claim 1 further comprising a flexible projection disposed in the first chamber for allowing insertion of a container into the first chamber and preventing removal of the container from the first chamber.

21. An injection device for use with a cartridge containing an injectate, the injection device comprising: a housing including: an end wall at a distal end of the housing; a wall extending in a direction from a proximal end of the housing toward the distal end, the wall defining a chamber, the chamber extending along a first axis; a first opening disposed in the end wall and in fluid communication with the chamber; and a coupler including a second opening and configured to couple the cartridge to the housing such that the cartridge extends along a second axis, where an angle between the first axis and the second axis is nonzero; wherein the first opening and the second opening are in fluid communication via a channel for transfer of fluid between the chamber and the coupler chamber.

Description

DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a needle-free transdermal injection device.

[0026] FIG. 2 is a first embodiment of a fluid transfer mechanism.

[0027] FIG. 3 shows a fluid transfer operation of the fluid transfer mechanism of FIG. 2.

[0028] FIG. 4 shows an injection operation of the fluid transfer mechanism of FIG. 2.

[0029] FIG. 5 shows a second embodiment of a fluid transfer mechanism.

[0030] FIG. 6 shows a third embodiment of a fluid transfer mechanism.

[0031] FIG. 7 shows a fluid transfer operation of the fluid transfer mechanism of FIG. 6.

[0032] FIG. 8 shows an injection operation of the fluid transfer mechanism of FIG. 6.

[0033] FIG. 9 is a perspective view of a covering for attachment to a distal end of the fluid transfer mechanism.

[0034] FIG. 10 is a fourth, non-parallel embodiment of a fluid transfer mechanism.

[0035] FIG. 11 is a fifth embodiment, end-to-end embodiment of a fluid transfer mechanism.

[0036] FIG. 12 is a sixth, end-to-end embodiment of a fluid transfer mechanism.

DESCRIPTION

[0037] Referring to FIG. 1, a needle-free transdermal injection device 100 includes an injector mechanism 102 with a fluid transfer mechanism 104 attached thereto. Very generally, the injector mechanism 102 operates the fluid transfer mechanism 104 to eject an injectate from an injectate cartridge therein and to deliver the ejected injectate through the skin and into the bloodstream of a patient. Referring to FIG. 2, one embodiment of the fluid transfer mechanism 204 includes a housing 206 which has a distal end 208 and a proximal end 210. The housing 206 includes an end wall 212 disposed at its distal end 208 and an inner wall 214 extending in a direction from the proximal end 210 of the housing 206 to the distal end 208 of the housing. The inner wall 214 separates a cartridge chamber 216 in the housing 206 from an injection chamber 218 (sometimes referred to as an injection bore or injectate bore) in the housing 206. In some examples, the injection chamber 218 has an injection plunger 219 slidably disposed therein for moving fluid into and out of the injection chamber 218, as is discussed in greater detail below.

[0038] The end wall 212 includes a fluid transfer opening 220 that is in fluid communication with the cartridge chamber 216 and an injection opening 222 that is in fluid communication with the injection chamber 218. A coupler 224 for coupling a cartridge, syringe or other container (not shown), including an injectate, to the fluid transfer mechanism 204 is disposed in the cartridge chamber 216 and is in fluid communication with the fluid transfer opening 220.

[0039] In FIG. 2, the coupler 224 is shown schematically. However, it is noted that in some examples, the coupler 224 includes a needle for piercing a pierceable membrane of the cartridge. In other examples, the coupler 224 includes a Luer-type connector for coupling to a cartridge or syringe with a corresponding Luer-type connector. In yet other examples, the coupler 224 includes a pierceable membrane or insert for receiving a needle of a cartridge or syringe.

[0040] In various configurations of the fluid transfer mechanism 204 described herein, the fluid transfer opening 220 in the cartridge chamber 216 is in fluid communication with the injection opening 222 of the injection chamber 218. Very generally, in certain configurations a channel 230 exists between the fluid transfer opening 220 and the injection opening 222 through which fluid (e.g., injectate) can flow between the cartridge chamber 216 and the injection chamber 218.

[0041] In the embodiment of FIG. 2, the fluid transfer mechanism 204 includes a covering 228 which covers some or all of the end wall 212 including the fluid transfer opening 220 and the injection opening 222. In some examples, the covering 228 is attached to the end wall 212 using an adhesive. In other examples, the covering 228 is attached to the end wall using other attachment techniques such as heat sealing or laser bonding techniques.

[0042] Regardless of the attachment technique, a portion of the covering 228 is left unattached from the end wall 212 such that a fluid transfer channel 230 connecting the fluid transfer opening 220 and the injection opening 222 is formed between the covering 228 and the end wall 212. In some examples, the unattached portion of the covering 228 includes a groove (e.g., a vacuum formed blister, not shown) which is aligned to fluid transfer opening 220 and the injection opening 222 and defines the fluid transfer channel 230 between the covering 228 and the end wall 212. In some examples, the end wall 212 includes a corresponding groove such that a diameter of the fluid transfer channel 230 is increased. In other examples, the unattached portion of the covering 228 is configured to bulge away from the end wall 212 to form the channel 230, thereby allowing fluid transfer between the fluid transfer opening 220 and the injection opening 222. In general, fluid is prevented from leaking from the fluid transfer mechanism 204 by the covering 228.

[0043] In some examples, the covering 228 is made of a foil or pliable material and can be peeled off of the end wall 212 of the housing 206 prior to performing an injection (e.g., by grasping a tab 232 of the covering 228 and pulling). In some examples, the foil or pliable material is sufficiently thin to allow for injection through the foil, thereby obviating the need to remove the covering before performing the injection. In some examples, the covering 228 is made of a thin membrane (e.g., an air permeable, liquid impermeable membrane) through which an injection can be performed, in which case the covering 228 does not need to be removed prior to performing an injection.

[0044] Referring to FIG. 3, in a fluid transfer operation of the fluid transfer mechanism 204, an injectate cartridge 334 (or more generally, an injectate source) including a fluid injectate 336 (e.g., a drug or vaccine) is first inserted into the cartridge chamber 216 of the fluid transfer mechanism 204 such that a coupling mechanism 338 of the cartridge 334 engages the coupler 224 of the fluid transfer mechanism 204. For example, the coupling mechanism 338 of the cartridge 334 may be a rubber membrane or bung which is pierced by a needle in the cartridge chamber 218 (i.e., the coupler 224 of the fluid transfer mechanism 204).

[0045] With the injectate cartridge 334 engaged with the coupler 224, a cartridge plunger 321 in the cartridge 334 is moved from a starting position in the cartridge 334 in a direction away from the proximal end 210 of the housing 206 and toward the distal end 208 of the housing 206. The movement of the cartridge plunger 321 results in a positive pressure in a distal portion 340 of the cartridge 334. The positive pressure in the distal portion 340 of the cartridge 334 causes the fluid injectate 336 to flow out of the cartridge 334, out of the cartridge chamber 218 through the fluid transfer opening 220, through the channel 230, through the injection opening 222, and finally into the injection chamber 218. The fluid injectate 336 causes the injection plunger 219 to move from a starting position in the injection chamber 218 in a direction away from the distal end 208 of the housing 206 toward the proximal end 210 of the housing 206. It is noted that, in some examples, movement of the injection plunger 219 may be used to create a negative pressure in the injection chamber 218 in order to cause injectate to flow into the injection chamber 218.

[0046] In general, the movement of the cartridge plunger 321 is actuated by a device external to the fluid transfer mechanism 204 such as the injector mechanism 102 of FIG. 1 and is carefully controlled to ensure that a correct amount or dosage of fluid injectate 336 is transferred into the injection chamber 218 during the fluid transfer operation.

[0047] Referring to FIG. 4, after completion of the fluid transfer operation, with the correct amount or dosage of fluid injectate 336 is present in the injection chamber 218, the needle-free transdermal injection device 100 is prepared for an injection operation. In the case that a foil covering is attached to the end wall 212 of the housing 206 of the fluid transfer mechanism 204, a user of the device 100 first peels the foil covering off of the end wall 212. In doing so, the channel 230 between the end wall 212 and the covering is destroyed, eliminating the possibility of any additional fluid transfer between the cartridge chamber 216 and the injection chamber 218 and exposing the injection opening 222.

[0048] The user then positions the needle-free transdermal injection device 100 such that the injection opening 222 is aligned with a desired injection location on a patient's skin 442. With the injection opening 222 aligned to the desired injection location, the user triggers the needle-free transdermal injection device 100, causing the injection plunger 219 to rapidly move in the injection chamber 218 in a direction away from the proximal end 210 of the housing 206 and toward the distal end 208 of the housing 206. The rapid movement of the injection plunger 219 causes a positive pressure in the injection chamber 218 which in turn causes ejection of the fluid injectate 336 from the injection chamber 218 via the injection opening 222. The force of ejection of the fluid injectate 336 from the injection opening 222 causes delivery of the fluid injectate 336 through the skin and into the bloodstream of the patient.

[0049] It is noted that presence of the injection cartridge 334 in the cartridge chamber 216 is not necessary during the injection operation.

[0050] In some examples, when the covering 228 is a thin membrane, the covering 228 is left in place during the injection operation. In such cases, the channel 330 may be sufficiently narrow to ensure that little if any fluid injectate 336 is forced back into the cartridge chamber 216 during the injection operation. In some examples, a check valve is included in the cannel 330 to prevent backflow of fluid injectate 336 into the cartridge chamber 216 during the injection operation.

[0051] Referring to FIG. 5, in some examples, rather than having a covering attached to the end wall 212 of the housing 206, a removable cap 544 is used to cover the distal end 208 of the housing 206 and to establish a fluid transfer channel between the cartridge chamber 216 and the injection chamber 218.

[0052] In some examples, the cap 544 includes an internal channel 530 which has a first channel opening 546 and a second channel opening 548. When the cap 544 is attached to the distal end 208 of the housing 206, the first channel opening 546 is aligned with the fluid transfer opening 220 and the second channel opening 548 is aligned with the injection opening 222. By aligning the channel openings 546, 548 to the openings in the end wall 212 of the housing 206, the channel 530 establishes fluid communication between the cartridge chamber 216 and the injection chamber 218. With fluid communication established, fluid injectate 336 can be drawn from the cartridge chamber 216 into the injection chamber 218 through the channel 530 in the same manner as was described in relation to FIG. 3. The cap 544 can then be removed, destroying the fluid communication between the cartridge chamber 216 and the injection chamber 218. With the cap removed, the injection operation can be performed in the same manner as was described in relation to FIG. 4.

[0053] It is noted that in some examples, as in FIG. 5, the channel 530 is formed fully within the cap 544. However, in other examples, the channel 530 is formed between a surface feature (e.g. a groove) in the cap 544 and the end wall 212 of the housing 206 (a similar channel formation to that shown in FIG. 2).

[0054] Referring to FIG. 6, another embodiment of the fluid transfer mechanism 604 includes a housing 606 which has a distal end 608 and a proximal end 610. In some configurations, a cap 644 is attached to the distal end 608 of the housing 606. The housing 606 includes an end wall 612 disposed at its distal end 608 and an inner wall 614 extending in a direction from the proximal end 610 of the housing 606 to the distal end 608 of the housing 606. The inner wall 614 separates a cartridge chamber 616 in the housing 606 from an injection chamber 618 in the housing 606. In some examples, the injection chamber 618 has an injection plunger 619 slidably disposed therein for moving fluid into and out of the injection chamber 618.

[0055] A distal inner surface 650 of the cartridge chamber 616 includes a fluid transfer opening 620 that is in fluid communication with the cartridge chamber 616. A coupler 624 for coupling a cartridge (not shown) including an injectate to the fluid transfer mechanism 604 is disposed in the cartridge chamber 616 and is in fluid communication with the fluid transfer opening 620. The end wall 612 includes an injection opening 622 that is in fluid communication with the injection chamber 618.

[0056] As was the case above, the coupler 624 is shown schematically but should be understood to be one of any number of syringe or cartridge couplers that are well known in the art.

[0057] A fluid transfer channel 630 extends through the housing and connects the fluid transfer opening 620 and the injection opening 622, thereby establishing fluid communication between the two openings 620, 622. In some examples, the channel 630 includes a one-way valve 654 (e.g., a check valve) which only allows fluid to flow in a direction from the cartridge chamber 616 to the injection chamber 618. In other examples, a portion of 654 or the entire channel 630 has a relatively small diameter that restricts flow of fluid through the channel 630.

[0058] Referring to FIG. 7, in a fluid transfer operation of the fluid transfer mechanism 604, an injectate cartridge 734 including a fluid injectate 736 (e.g., a drug or vaccine) is first inserted into the cartridge chamber 616 of the fluid transfer mechanism 604 such that a coupling mechanism 738 of the cartridge 734 engages the coupler 624 of the fluid transfer mechanism 604. For example, the coupling mechanism 738 of the cartridge 734 may be a rubber membrane or bung which is pierced by a needle in the cartridge chamber 618 (i.e., the coupler 624 of the fluid transfer mechanism 604).

[0059] With the injectate cartridge 734 engaged with the coupler 624, a cartridge plunger 721 in the cartridge 734 is moved from a starting position in a direction away from the proximal end 610 of the housing 606 and toward the distal end 608 of the housing 606. The movement of the cartridge plunger 721 results in a positive pressure in a distal portion 740 of the cartridge 734. The positive pressure in the distal portion 740 of the cartridge 734 causes the fluid injectate 736 to flow out of the cartridge 734, out of the cartridge chamber 618 through the fluid transfer opening 620, through the channel 630, through the check valve 654, through the injection opening 622, and finally into the injection chamber 618. The fluid injectate 736 causes the injection plunger 619 to move from a starting position in the injection chamber 618 in a direction away from the distal end 608 of the housing 606 toward the proximal end 610 of the housing 606.

[0060] In general, the movement of the cartridge plunger 721 is actuated by a device external to the fluid transfer mechanism 204 such as the injector mechanism 102 of FIG. 1 and is carefully controlled to ensure that a correct amount or dosage of fluid injectate 736 is transferred into the injection chamber 618 during the fluid transfer operation.

[0061] Throughout the fluid transfer operation, the cap 644 prevents leakage of fluid injectate 736 out of the fluid transfer opening 622.

[0062] Referring to FIG. 8, after completion of the fluid transfer operation, with the correct amount or dosage of fluid injectate 736 is present in the injection chamber 618, a user of the needle-free transdermal injection device 100 may commence an injection operation.

[0063] The user first removes the cap 644 from the distal end 608 of the housing 606. The user then positions the needle-free transdermal injection device 100 such that the injection opening 622 is aligned with a desired injection location on a patient's skin 842. With the injection opening 622 aligned to the desired injection location, the user triggers the needle-free transdermal injection device 100, causing the injection plunger 619 to rapidly move in the injection chamber 618 in a direction away from the proximal end 610 of the housing 606 and toward the distal end 608 of the housing 606. The rapid movement of the injection plunger 619 causes a positive pressure in the injection chamber 618 which in turn causes ejection of the fluid injectate 736 from the injection chamber 618 via the injection opening 622. The force of ejection of the fluid injectate 736 from the injection opening 622 causes delivery of the fluid injectate 736 through the skin and into the bloodstream of the patient. Note that the check valve or channel restriction 654 of the channel 630 prevents or substantially limits flow of fluid injectate 736 back through the channel 630 and into the cartridge chamber 616 during the injection operation.

[0064] It is noted that presence of the injection cartridge 734 in the cartridge chamber 616 is not necessary during the injection operation.

[0065] Referring to FIG. 9, one example of a covering 950 for attachment to an end wall of a fluid transfer mechanism includes an attachment portion 952 and a channel portion 954. The attachment portion 952 is configured to make contact with and be attached to the end wall of the fluid transfer mechanism (e.g., by an adhesive, a heat sealing process, an ultrasonic welding process, or a laser bonding process). The covering 950 is attached to the end wall of the fluid transfer device such that the channel portion is aligned with, and establishes fluid communication between the injection opening and the fluid transfer opening of the fluid transfer device.

[0066] In some examples, during attachment of the attachment portion 952 to the end wall of the fluid transfer device, a seal ring 956 is formed between the end wall and the attachment portion 952. The seal ring 956 prevents unintended leakage of fluid from the channel portion 954 during a fluid transfer operation.

[0067] In some examples, a vacuum forming process is used to form the channel portion 954 (e.g., as a blister).

[0068] In some embodiments, the cartridge chamber (and the cartridge disposed therein) is shown as being oriented in parallel and beside the injection chamber. However, it is not an essential feature that the cartridge chamber (and the cartridge disposed therein) is oriented in parallel and beside the injection chamber. Indeed, many orientations between the two chambers are possible.

[0069] Referring to FIG. 10, in some examples, the fluid transfer device 1058 is configured such that an axis, A.sub.1 along which the cartridge chamber 1016 extends is at an angle, relative to an axis, A.sub.2 along which the injection chamber 1018 extends. As was the case in the embodiment shown in FIG. 5, a removable cap 1044 is used to cover the distal end 1008 of the housing 1006 and to establish a fluid transfer channel between the cartridge chamber 1016 and the injection chamber 1018.

[0070] The cap 1044 includes an internal channel 1030 which has a first channel opening 1046 and a second channel opening 1048. When the cap 1044 is attached to the distal end 1008 of the housing 1006, the first channel opening 1046 is aligned with the fluid transfer opening 1020 and the second channel opening 1048 is aligned with the injection opening 1022. By aligning the channel openings 1046, 1048 to the openings in the end wall 1012 of the housing 1006, the channel 1030 establishes fluid communication between the cartridge chamber 1016 and the injection chamber 1018. With fluid communication established, fluid injectate can be drawn from the cartridge chamber 1016 into the injection chamber 1018 through the channel. The cap 1044 can then be removed, destroying the fluid communication between the cartridge chamber 1016 and the injection chamber 1018.

[0071] It is noted that in some examples, the channel 1030 is formed fully within the cap 1044. However, in other examples, the channel 1030 is formed between a surface feature (e.g. a groove) in the cap 1044 and the end wall 1012 of the housing 1006. In some examples the fluid transfer device 1058 of FIG. 10, lacks the walls which define the cartridge chamber in other embodiments of the fluid transfer device.

[0072] Referring to FIG. 11, in some examples, a cartridge 1134 (shown as a syringe in FIG. 11) and an injection head 1117 (including an injection chamber 1118) are arranged in a fluid transfer device 1158 in a first end-to-end configuration. In the first end-to-end configuration, the distal end of the injection head 1117 is disposed in the fluid transfer device 1158 with the injection opening 1122 adjacent to the fluid transfer channel 1130. The fluid transfer device 1158 is configured such that an axis, A.sub.1 along which the cartridge chamber 1116 extends is at an angle, =180 relative to an axis, A.sub.2 along which the injection chamber 1118 extends.

[0073] In FIG. 11, a needle of the syringe 1134 has punctured a bung 1135 of the fluid transfer device 1158 and has entered a fluid transfer chamber 1130 which is in fluid communication with the injection chamber 1118. A user pushing on a plunger of the syringe 1134 causes transfer of injectate (not shown) from the syringe 1134, through the fluid transfer channel 1130, and into the injection chamber 1118 via an injection opening 1122.

[0074] In some examples, the injector head 1117 with injectate disposed therein can be removed from the fluid transfer device 1158 and installed on a needle-free injection device for injection of injectate into a patient.

[0075] Referring to FIG. 12, in some examples, a cartridge 1234 (shown as a syringe in FIG. 12) and an injection head 1217 (including an injection chamber 1218) are arranged in a fluid transfer device 1258 in a second end-to-end configuration. In the second end-to-end configuration, the proximal end of the injection head 1217 is disposed in the fluid transfer device 1258 a bung 1235 of the cartridge 1234 disposed adjacent to a channel 1230. The fluid transfer device 1258 is configured such that an axis, A.sub.1 along which the cartridge chamber 1216 extends is at an angle, =180 relative to an axis, A.sub.2 along which the injection chamber 1218 extends.

[0076] In FIG. 12, a needle of the syringe 1234 has punctured a bung 1235 disposed in the rear of the injection head 1217 (which, in some examples, is also the cartridge plunger) and has entered the injection chamber 1218. A user pushing on a plunger of the syringe 1234 causes transfer of injectate (not shown) from the syringe 1234 and into the injection chamber 1218. As injectate is transferred into the injection chamber 1218, air in the injection chamber 1218 is ejected via an injection opening 1222.

[0077] In some examples, the injector head 1217 with injectate disposed therein can be removed from the fluid transfer device 1258 and installed on a needle-free injection device for injection of injectate into a patient.

ALTERNATIVES

[0078] In some examples, the cartridge chamber includes a latching mechanism that allows for a cartridge, syringe, or other container to be inserted into the cartridge chamber but prevents removal of the container from the cartridge chamber. For example, the cartridge container may have a flexible catch that allows a shoulder of a container to pass beyond the catch but engages the shoulder of the container to prevent removal of the container from the cartridge chamber.

[0079] In some examples, the caps described above are made from hard plastic material. In some examples, the caps are made from a soft elastomer material. In some examples, the caps are threaded and engage a corresponding thread on the distal end of the housing of the fluid transfer mechanism.

[0080] In some examples, at completion of the fluid transfer operation, a rubber bung engages the coupler (e.g., needle) in the cartridge chamber and seals the coupler off from the cartridge chamber, thereby preventing flow of fluid through the channel and into the cartridge chamber during an injection operation.

[0081] It is noted that the term cartridge as used throughout this specification is not intended to limit the application to any particular container or device for holding injectate. In the context of this specification, the term cartridge should be understood as pertaining to any container for holding and allowing extraction of fluids such as medicaments.

[0082] It should be understood that the terms fluid and fluid injectates as used herein should be interpreted broadly to include liquid solutions, gaseous solutions, fluids (e.g., liquids or gases such as air) with solids suspended therein, and any other types of materials that can be forced to flow through the channel.

[0083] It should be noted that, while the fluid transfer mechanisms described above are described in the context of a needle-free injection mechanism, at least some of the approaches may also be used for fluid transfer in a needle-based injection mechanism.

[0084] It is to be understood that the foregoing description is intended to illustrate and not to limit the scope of the invention, which is defined by the scope of the appended claims. Other embodiments are within the scope of the following claims.