Abstract:
Catheter securement devices are generally described for securing the catheter hub to the access site following successful catheterization. Examples of catheter assemblies with integrated securing mechanisms and related methods are disclosed. The integrated device provides convenience and easy to use access to securing devices that are integrated to the wings of the catheter assemblies.

Description:
FIELD OF ART 
       [0001]    The present disclosure generally relates to catheter devices and more particularly to catheter devices having securing mechanisms and related methods. 
       BACKGROUND 
       [0002]    After successful catheterization of an indwelling catheter to a patient, the access site where the catheter tube enters the skin is secured to prevent the catheter from moving or inadvertently withdrawing from the vessel of the patient. To secure the catheter to the patient, a practitioner typically uses tape or other catheter stabilization devices. These catheter stabilization devices are usually separate products that come in their own packaging. 
       SUMMARY 
       [0003]    The various embodiments of a catheter device having a securing mechanism have several features, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of the present embodiments as set forth in the claims that follow, their more prominent features now will be discussed briefly. 
         [0004]    Aspects of the present disclosure include a catheter assembly with securing mechanisms which includes a catheter hub unit comprising a catheter hub, a catheter tube extending distally from the catheter hub, and two wings each extending laterally of the catheter hub, a needle hub unit comprising a needle hub and a needle extending distally from the catheter hub and projecting through the catheter tube in a ready position, an anchor sheet located on each of the wings, each anchor sheet comprising a top side facing away from a corresponding wing and a bottom side facing the corresponding wing in the ready position, an adhesive layer provided on the top side of each anchor sheet, and a release liner covering the adhesive layer on each anchor sheet in the ready position. Each anchor sheet can be pivotably connected to the corresponding wing. 
         [0005]    Each anchor sheet can be pivotably connected to the corresponding wing in a different direction from each other. 
         [0006]    Each wing can be shaped differently from the other wing. A recessed space can be formed in each wing, the recessed space being configured for securing the anchor sheet in the ready position. 
         [0007]    A tab can extend from each anchor sheet, the tab being configured for pulling the anchor sheet from the recessed space. 
         [0008]    A release liner tab can extend from the release liner. 
         [0009]    Each anchor sheet can be pivotably connected to the respective wing by adhesive along a pivoting edge on the anchor sheet. The pivoting edge for each wing can differ in location from the other or be the same. 
         [0010]    An anchor sheet can be provided on a bottom exterior surface of the catheter hub in addition to the anchor sheets on the wings. 
         [0011]    Each anchor sheet can be pivotably connected to the respective wing by a living hinge. 
         [0012]    The living hinge can be located at a proximal end of the wing. 
         [0013]    The release liner can be attached to the needle hub unit, such that withdrawing the needle hub unit from the catheter hub unit rotates the anchor sheet and removes the release liner. 
         [0014]    The anchor sheets can include a plurality of connected subsections folded upon each other in an accordion fashion to form folded anchor sheets. 
         [0015]    The needle hub unit can further comprise a pair of tethers attached to a free end of the folded anchor sheets. 
         [0016]    The folded anchor sheets can be stored in a storage space in the wing. The folded anchor sheets can be tucked under the wing. The folded anchor sheets can unfold to extend in a same first direction. 
         [0017]    One of the two folded anchor sheets can unfold to extend in a distal direction with the adhesive facing down, and the other of the two anchor sheets can unfold to extend in a proximal direction with the adhesive facing down. 
         [0018]    Because the anchor sheets are accessible once applied to a patient, they can easily be lifted and removed to facilitate removing the catheter hub from the patient. For example, the anchor sheets can be lifted directly using fingers or other means to remove the catheter hub from the patient. Anchor sheets that are not directly accessible, such as being located only on lower surfaces of the wings or the catheter hub, can be difficult to remove. 
         [0019]    Another aspect of the present disclosure includes a method of manufacturing a catheter assembly which includes extending a catheter tube distally from a catheter hub, a left wing laterally from a left side of the catheter hub, and a right wing laterally from a right side of the catheter hub, extending a needle from a needle hub unit through the catheter tube in a ready position, pivotably connecting an anchor sheet to the left wing and another anchor sheet to the right wing, each anchor sheet comprising a top side facing away from a corresponding wing and a bottom side facing the corresponding wing in the ready position, the top side having an adhesive layer, and covering the adhesive layer on each anchor sheet with a release liner. 
         [0020]    Each anchor sheet can be pivotably connected to the corresponding wing in a different direction from each other. 
         [0021]    A recessed space can be formed in each wing, the recessed space securing the anchor sheet in the ready position. 
         [0022]    The method can further include pulling the anchor sheet from the recessed space. 
         [0023]    Each anchor sheet can be pivotably connected to the corresponding wing by a living hinge. 
         [0024]    The living hinge can be located at a proximal end of the wing. 
         [0025]    The method can further include withdrawing the needle hub from the catheter hub thereby rotating the anchor sheet and removing the release liner, wherein the release liner is attached to the needle hub. 
         [0026]    The method can further include folding the anchor sheets into a plurality of connected subsections folded upon each other in an accordion fashion. 
         [0027]    The method can further include unfolding the anchor sheets by pulling a free end of the folded anchor sheets with tethers attached to the needle hub. 
         [0028]    The method can further include storing the anchor sheets in a storage space in the wing. 
         [0029]    The method can further include tucking the folded anchor sheets under the wing. 
         [0030]    The method can further include folding the anchor sheets over the wings towards a distal direction after unfolding the anchor sheets. 
         [0031]    The method can further include unfolding the anchor sheets in different directions. 
         [0032]    The method can further comprise providing direct access to the anchor sheets so that they can be gripped, such as by an instrument or by fingers. 
         [0033]    The method can further comprise the step of applying the anchor sheets to a patient. 
         [0034]    The method can further comprise the step of directly gripping the anchor sheets and lifting the anchor sheets away from the patient. 
         [0035]    Each anchor sheet can be removed from the skin of the patient with or without tabs for easy removal of the catheter. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0036]    These and other features and advantages of the present device, system, and method will become appreciated as the same becomes better understood with reference to the specification, claims and appended drawings wherein: 
           [0037]      FIG. 1  shows one embodiment of a catheter assembly, the catheter assembly including a catheter hub unit and a needle hub unit; 
           [0038]      FIG. 2  shows the catheter assembly of  FIG. 1  with release liners of the catheter hub unit being removed; 
           [0039]      FIG. 3  shows the catheter assembly of  FIG. 1  with anchor sheets of the catheter hub unit pivoted from the wings; 
           [0040]      FIG. 4  shows another embodiment of a catheter assembly; 
           [0041]      FIG. 5  shows an enlarged view of the circular portion  5 - 5  of  FIG. 4 ; 
           [0042]      FIGS. 6-9  show various stages of separating a needle hub unit from a catheter hub unit of yet another embodiment of a catheter assembly, the catheter hub unit including wings and anchor sheets attached to the wings, and the needle assembly tethered to the anchor sheets; 
           [0043]      FIG. 10  shows one embodiment of wings of the catheter assembly of  FIG. 6 ; 
           [0044]      FIG. 11  shows another embodiment of wings of the catheter assembly of  FIG. 6 ; and 
           [0045]      FIG. 12  shows a front view of the catheter assembly of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiments of catheter assemblies for use in various applications provided in accordance with aspects of the present devices, systems, and methods and is not intended to represent the only forms in which the present devices, systems, and methods may be constructed or utilized. The description sets forth the features and the steps for constructing and using the embodiments of the present devices, systems, and methods in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the present disclosure. As denoted elsewhere herein, like element numbers are intended to indicate like or similar elements or features. 
         [0047]      FIG. 1  illustrates one embodiment of a catheter assembly  100 , which includes a catheter hub unit  101  and a needle hub unit (conventional and shown in  FIG. 4 ). The catheter hub unit  101  includes a catheter hub  102 , a catheter tube  104  connected to a distal end of the catheter hub  102 , and a pair of wings  106   a,    106   b  extending laterally from the catheter hub  102 . For example, a first or left wing  106   a  extends from a left side of the catheter hub  102 , and a second or right wing  106   b  extends from a right side of the catheter hub  102 . 
         [0048]    A proximal end opening  44  of the catheter hub  102  may include a female Luer fitting (not shown) having a female Luer taper and/or female Luer lock threads. The female Luer fitting is thus configured to matingly receive a male Luer connector, such as used in connection with an IV line, a Luer access connector, a needle hub, a syringe tip, a vent plug, or another known or future-developed IV devices. Each of these components can be sized and configured in conformity with at least some of the International Standards Organization (ISO) standards for female and male Luer connections under current or future standards. 
         [0049]    The catheter tube  104  is shown penetrated under the skin into the vein of a patient at an access site  108 . Typically, a needle tip of a needle extends through a hollow interior cavity of the catheter hub  102  from a distal end of the needle hub and out the distal opening of the catheter tube  104 , prior to insertion into the patient at the access site  108 . The needle tip can also extend through various components such as a valve, a valve actuator, and a needle guard, positioned in the hollow interior cavity of the catheter hub  102 , the examples of which can be found in U.S. Pat. No. 8,333,735, the contents of which are expressly incorporated herein by reference. The needle guard may also be located outside of the catheter hub as disclosed in U.S. Pat. No. 8,597,249, the contents of which are expressly incorporated herein by reference. 
         [0050]    A distal portion of the catheter tube  140  can taper inwardly or the distal opening can have a size smaller than an outer diameter of the needle to form a seal around the opening of the catheter tube  103  with the needle to prevent fluid from entering the annular space between the catheter tube  102  and the needle when the needle tip pierces the skin of the patient. After verification of proper needle and catheter tube placement, retraction of the needle tip in a proximal direction will allow fluid or blood to flow into the annular space between the needle and the interior of the catheter tube  102 , known as secondary blood flashback. After the needle tip and distal end of the catheter tube  104  has penetrated and accessed the vein, the needle hub is then withdrawn from the catheter hub unit  101  to remove the needle from the catheter hub  102 . When incorporated, a needle guard will activate to cover the needle tip to prevent inadvertent needle stick. 
         [0051]    In the example shown, an anchor sheet  110  is provided on each wing  106   a,    106   b.  The anchor sheet  110  is configured to secure the catheter hub unit  101  to the patient and prevent the catheter hub unit  101 , including the catheter tube  104 , from shifting in and out, or around the access site  108 , where the catheter tube penetrates the skin. Each anchor sheet  110  has a top side and an opposed bottom side facing the respective wing  106   a,    106   b.  The top side of each anchor sheet  110  is provided with an adhesive, such as a hypoallergenic adhesive or a pressure-sensitive adhesive, and a release liner  112  for covering the adhesive until use. In one embodiment, each anchor sheet  110  is securely attached to the respective wing  106   a,    106   b  along a pivoting edge  116 . In another embodiment, each anchor sheet  110  is securely attached to the respective wing  106   a,    106   b  along a pivoting edge  116  and wedged in a recessed space  124  defined by a perimeter lip  50  of the respective wing  106   a,    106   b  to hold the anchor sheet  110  in place prior to use. The pivoting edge  116  of the two anchor sheets can be located at any edge of the wings  106   a,    106   b . In one embodiment, the location of the two pivoting edges  116  of the two anchor sheets  110  are reversed. For example, the pivoting edge  116  at the left wing  106   a  is on the distal side  118  of the left wing  106   a  while the pivoting edge  116  at the right wing  106   b  is on the proximal side  120  of the right wing  106   b.  In another embodiment, the location of the two pivoting edges  116  can also be located on the same side such as the distal side  118  or the proximal side  120  of the wings  106   a,    106   b.  In yet another embodiment, the location of the two pivoting edges  116  are at the edges furthest away from the catheter hub  102 . The wings  106   a,    106   b  can be symmetrically identical or different from each other. In the illustrated embodiment, the wings  106   a,    106   b  are shaped such that the pivoting edge  116  is sufficiently long enough to adequately secure the catheter hub unit  101  to the patient and provide a minimum rotation or movement at the pivoting edge  116 . A tab  114  extends outwardly from each anchor sheet  110  to allow a user to pull the anchor sheet  110 , such as from the recessed space  124  of the respective wing  106   a,    106   b,  or the surface of the respective wings  106   a,    106   b  if no recessed space  124  is provided. In a particular example, each pivoting edge  116  comprises a band of permanently bonded anchor sheet layer, bonded to the surface of the respective wing  106   a,    106   b,  with a folded line along or adjacent the band to form a fold for pivoting. 
         [0052]      FIG. 2  shows the release liner  112  being removed from the top side of each anchor sheet  110  and the anchor sheet  110  lifted from the recessed space  124  of the respective wing  106   a ,  106   b  by pulling up on the tab  114  or by removal of the release liner  112  from a different gripping process or location of the release liner. A tab liner  115 , which may also be called a release liner tab, can extend from the release liner  112  to help separate the release liner  112  from the anchor sheet  110 . For example, if there is no adhesive on the tab  114  and the tab liner  115  overlaps the tab  114  of the anchor sheet, a user can easily grip the tab liner  115  to pull off the release liner  112 . No adhesive on the tab  114  also allows a user to easily remove the anchor sheet  110  from the patient when removing the catheter hub unit  101  from the patient, by gripping and pulling the anchor sheet  110  from the tab  114 . In another example, the anchor sheet  110  does not have a tab  114  and the anchor sheet  110  is lifted from the recessed space  124  of the respective wing  106   a,    106   b  by pulling on the release liner tab  115  or gripping one of the edges of the anchor sheet. 
         [0053]      FIG. 3  shows the two anchor sheets  110  rotated along the pivoting edge  116  so that the top side of each anchor sheet  110 , which is provided with adhesive, can be pressed against the skin of the patient to secure the catheter hub unit  101  and the catheter tube  104  to the access site  108 . After the release liner  112  is removed from the anchor sheet  110  to expose the adhesive on the top side of the respective anchor sheet  110 , the anchor sheet  110  is removably fixed to the skin of the patient by pressing against the bottom side  122  of the anchor sheet  110  to press the now exposed adhesive layer on the top side against the skin of the patient. In some examples, the recessed space  124  of each wing  106   a,    106   b  may be provided with a testing device or instrument, such as a glucose strip, which is only exposed after the anchor sheets  110  are pivoted and bonded to the patient. 
         [0054]      FIG. 4  shows another embodiment of a catheter assembly  200  which includes a catheter hub unit  201  and a needle hub unit  209  attached to a proximal end of the catheter hub unit  201 . The catheter hub unit  201  includes a catheter hub  202 , a catheter tube  203  extending distally from the catheter hub  202 , and a pair of wings  208  extending laterally from the catheter hub  202 . In the example shown, an anchor sheet  210  is provided with each wing  208  and each anchor sheet  210  has an adhesive layer or coat covered by a release liner  220 . The needle hub unit  209  shown includes a needle hub  204  attached to the proximal end of the catheter hub  202 , and a needle  205  extending distally from the needle hub  204  and through the catheter hub  202  and the catheter tube  203 . The catheter assembly  200  is similar to the catheter assembly  100  of  FIG. 1 , except that the anchor sheet  210  is integrally formed with the wing  208 , as further discussed below. 
         [0055]    With reference now to  FIG. 5 , which is an enlarged view of one of the wings of  FIG. 4 , the anchor sheet  210  is shown attached to the wing  208  along a hinge  212 . In the illustrated embodiment, the hinge  212  is located at a proximal side of the wing  208 . However, the location of the hinge  212  is not limited and can be located at any of the various sides of the wing  208 . In the example shown, the anchor sheet  210  is unitarily formed with the wing  208  and the hinge  212  is a living hinge. Thus, the anchor sheet  210  is made from the same thermoplastic material as the wing  208 . When in the ready to use position as shown in  FIG. 4 , the anchor sheet  210  has a top side  214  facing away from the wing  208  and a bottom side  216  facing the wing  208 . To temporarily secure the anchor sheet  210  to the wing  208  in the ready to use position, detents or a weak adhesive can be used. 
         [0056]    Hypoallergenic adhesive or pressure-sensitive adhesive may be provided on the top side  214  of each anchor sheet  210  and is protected by a release liner  220 .  FIG. 5  shows the anchor sheet  210  pivoted away at the hinge  212  from the wing  208  with the release liner  220  in the process of being removed from the top side  214  of the anchor sheet  210 . In one embodiment, the two release liners  220  are secured to the needle hub  204  so that upon retraction of the needle hub unit  209  away from the catheter hub unit  201  following successful catheterization, the anchor sheets  210  are pulled by the retracting needle hub unit  209  and automatically rotated about the hinge  212 . Concurrently therewith, the release liners  220  are automatically removed from the anchor sheets  210  thereby exposing the adhesive for attaching to the patient. In another embodiment, the two release liners  220  are not attached to the needle hub unit  209  and can be removed from the anchor sheets  210  manually by the user. Once the release liner  220  is completely removed from the anchor sheet  210 , force is applied to the bottom side  216 , now rotated to face up with respect to the wing  208  as shown in  FIG. 5 , to press the adhesive against the skin, thus securing the catheter hub  202  and the catheter tube  203  to secure the access site from unwanted or from excessive movement. 
         [0057]    With reference now to  FIG. 6 , yet another embodiment of a catheter assembly  300  is shown partially inserted into an access site  108 . The catheter assembly  300  includes a catheter hub unit  301  and a needle hub unit  309  attached to a proximal end of the catheter hub unit  301 . The catheter hub unit  301  includes a catheter hub  302 , a catheter tube  303  extending distally from the catheter hub  302 , and a pair of wings  306   a,    306   b  extending laterally of the catheter hub  302 . An anchor sheet  310   a,    310   b  ( FIG. 7A ) is provided with each corresponding wing  306   a ,  306   b,  and each has an adhesive layer or coat, as further discussed below. The needle hub unit  309  includes a needle hub  304  attached to the proximal end of the catheter hub  202 , and a needle  305  with a sharpened distal tip extending distally from the needle hub  304  and through the catheter hub  302  and the catheter tube  303 . The catheter assembly  300  is similar to the catheter assembly of  FIG. 1  except that the anchor sheets  310   a,    310   b  are folded upon each other in an accordion fashion, with or without a separate release liner. In the illustrated embodiment, a pair of tethers  308   a,    308   b  are connected to the needle hub  304  and to the folded anchor sheets  310   a ,  310   b,  and the folded anchor sheets  310   a,    310   b  have ends that are connected to the catheter hub  202 . In an alternative embodiment, the tethers  308   a,    308   b  are omitted and the two folded anchors sheets  310   a,    310   b  are to be activated or deployed when a user grips and manipulates them. 
         [0058]      FIG. 7A  shows the needle hub  304  retracted away from the catheter hub  302 , such as following successful catheterization. Referring also to  FIG. 7B , the folded anchor sheets  310   a ,  310   b  each includes a plurality of connected subsections  311  stacked upon each other. The length and width of the connected subsections  311  can vary depending on the design. In addition, the shape of the connected subsections is not limited to square or rectangular, but can be any regular or irregular shape. In the process of retracting the needle hub unit  309  from the catheter hub unit  301 , such as following successful venipuncture, the tethers  308   a,    308   b,  which are attached to the two folded anchors sheets  310   a,    310   b,  pull the two folded anchor sheets  310   a,    310   b  away from the two wings  306   a,    306   b.  When pulled, the folded and connected subsections  311  of the anchor sheets  310   a,    310   b  are unfolded and lengthen. Each unfolded anchor sheet  310   a,    310   b  comprises a top side  312  and a bottom side  315  opposite the top side. The anchor sheets  310   a,    310   b  are provided with hypoallergenic adhesive or pressure-sensitive adhesive on at least some portions or substantially all along the top side  312 . In one example, the adhesive is only on the top side  312  of every other connected subsection  311 , such that the adhesive will be protected by an adjacent subsection  311  without the adhesive, which acts as a release liner. In another example, the adhesive is on substantially the entire top side  312  of the anchor sheet  310   a,    310   b.  In yet another example, a separate release liner is provided to cover the adhesive on the top side  312  of the anchor sheet  310   a,    310   b.  The connected subsections  311  can be formed by simple folds, double folds, or various fold patterns from an elongated sheet with uniform or non-uniform outer edges to form a sufficiently compact configuration for storage under the wings in a ready to use position. 
         [0059]      FIG. 8  shows the needle hub unit  309  completely separated from the catheter hub unit  301 . The two tethers  308   a,    308   b  are separated from the two folded anchor sheets  310   a,    310   b . Perforations or weakened sections may be provided at attachment points between the tethers  308   a,    308   b  and the anchor sheets  310   a,    310   b  to facilitate separation. In one example, the tethers  308   a,    308   b  are lightly attached to at least one connected subsection  311  of the anchor sheets  310   a,    310   b  and detach from the anchor sheets  310   a,    310   b  when the anchor sheets  310   a,    310   b  are fully extended. In another example, if a separate release liner is provided, the release liner is also attached to the tethers  308   a,    308   b  and removed from the anchor sheets  310   a,    310   b  when the tethers  308   a,    308   b  are separated from the two folded anchor sheets  310   a,    310   b.    
         [0060]    Referring to  FIG. 9 , the two folded anchor sheets  310   a,    310   b  are folded over the two wings  306   a,    306   b  with a plurality of straightened connected subsections  311  extending beyond the wings  306   a,    306   b.  The bottom sides  314  of the anchor sheets  310   a,    310   b  are pressed against the skin to adhere the anchor sheets  310   a,    310   b  to the skin to secure the catheter hub  302  and the catheter tube  303  to the access site  108 . In some examples, surfaces on an underside  54  of the wings are also provided with adhesive to further secure the wings to the skin of the patient. 
         [0061]      FIG. 10  shows one configuration for storing the folded anchor sheets  310   a,    310   b  underneath the wings  306   a,    306   b.  In the illustrated embodiment, the anchor sheets  310   a,    310   b  are folded and attached to the exterior underside  54  of the wings in the ready to use position of  FIG. 6 , which is the side that faces the patient when pressed against the patient. Each tether  308   a,    308   b  (not shown) is attached to a respective free end of the anchor sheet  310   a,    310   b,  or possibly even near the respective free end if not right at the free end. 
         [0062]      FIG. 11  shows a second configuration for storing the folded anchor sheets  310   a,    310   b  underneath the wings  306   a,    306   b.  In the present embodiment, the anchor sheets  310   a,    310   b  are folded and attached to a hollow space or a storage space  314   a,    314   b  inside each respective wing  310   a,    310   b.    FIG. 12  shows each wing  306   a,    306   b  having the storage space  314   a,    314   b.  The folded anchor sheets  310   a,    310   b  are tucked away inside the storage space  314   a,    314   b  in the ready to use position. The tethers  308   a,    308   b  (not shown) attach to the free ends of the anchor sheets  310   a,    310   b.  The location of the folded anchor sheets  310   a,    310   b  is not limited and can be stored anywhere on the wing such as underneath the wings  306   a,    306   b  as discussed above for  FIGS. 6-12  or above the wings  306   a,    306   b.  For example, the anchor sheets  310   a,    310   b  can be folded and attached at a top of the wings in the ready to use position of  FIG. 6 . 
         [0063]    It is also understood that the top or bottom sides  312 ,  315  of the anchor sheets  310   a,    310   b  having the adhesive could be applied to the skin in any direction such as in a direction towards the access site  108  or away from the access site  108 , depending which of the top or bottom sides  312 ,  315  the adhesive is located. Thus, both anchor sheets  310   a,    310   b  can be applied to the skin of the patient in a direction toward the access site  108 , or away from the access site  108 . In another embodiment, the adhesive is applied to the bottom side  315  of one anchor sheet and to the top side of one anchor sheet, such that one anchor sheet  310   a  is applied to the skin of the patient in one direction, and the other anchor sheet  310   b  is applied to the skin of the patient in the other opposite direction. 
         [0064]    Methods of making and of using the catheter assemblies with securing mechanisms and their components as discussed elsewhere herein are within the scope of the present invention. 
         [0065]    Although limited embodiments of various catheter assemblies having a securing mechanism of the anchor sheets have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. For example, any over the catheter assemblies can benefit by using the securing mechanism disclosed herein to provide quicker attachment to the patient. Furthermore, it is understood and contemplated that features specifically discussed for one catheter assemblies with securing mechanisms may be adopted for inclusion with another catheter assembly provided the functions are compatible. Accordingly, it is to be understood that the catheter assemblies with securing mechanisms and their components constructed according to principles of the disclosed devices, systems, and methods may be embodied other than as specifically described herein. The disclosure is also defined in the following claims.