Abstract:
Generally described herein are apparatus, systems and methods related to a stem insertable into the access port tubing for the prevention of fluid leaks. More particularly, the stem or stems may be larger than the interior diameter of the access port tubing thereby providing a fluid seal to keep the fluid within the access port tubing. However, these fluid seals might not be absolute and may still allow a certain degree of leakage. In one embodiment, by including barbs which further presses against the interior diameter of the access port tubing, the sealing of the fluid may be substantially improved. The stem itself, while impenetrable by a needle, may still allow for bend flexibility of the access port tubing by employing a ball and socket joint for connecting to a next stem. In this manner, fluid leak prevention is improved while retaining the mobility of the access port tubing.

Description:
FIELD 
     The present invention generally relates to medical systems, devices and uses thereof for treating obesity and/or obesity-related diseases. More specifically, the present invention relates to one or more stems for guarding against needle sticks as related to an access port used as a part of a gastric banding system implantable in a patient. 
     BACKGROUND 
     Adjustable gastric banding apparatus have provided an effective and substantially less invasive alternative to gastric bypass surgery and other conventional surgical weight loss procedures. Despite the positive outcomes of invasive weight loss procedures, such as gastric bypass surgery, it has been recognized that sustained weight loss can be achieved through a laparoscopically-placed gastric band, for example, the LAP-BAND® (Allergan, Inc., Irvine, Calif.) gastric band or the LAP-BAND AP® (Allergan, Inc., Irvine, Calif.) gastric band. Generally, gastric bands are placed about the cardia, or upper portion, of a patient&#39;s stomach forming a stoma that restricts food&#39;s passage into a lower portion of the stomach. When the stoma is of an appropriate size that is restricted by a gastric band, food held in the upper portion of the stomach may provide a feeling of satiety or fullness that discourages overeating. Unlike gastric bypass procedures, gastric band apparatus are reversible and require no permanent modification to the gastrointestinal tract. An example of a gastric banding system is disclosed in Roslin, et al., U.S. Patent Pub. No. 2006/0235448, the entire disclosure of which is incorporated herein by this specific reference. 
     Over time, a stoma created by a gastric band may need adjustment in order to maintain an appropriate size, which is neither too restrictive nor too passive. Accordingly, prior art gastric band systems provide a subcutaneous fluid access port (“access port”) connected to an expandable or inflatable portion of the gastric band. By adding fluid to or removing fluid from the inflatable portion by means of a hypodermic needle inserted into the access port, the effective size of the gastric band can be adjusted to provide a tighter or looser constriction. 
     Typically, the access port, and in particular, the tubing leading from the access port to a reservoir or the inflatable portion of the gastric band may be susceptible to a misdirected needle. That is, a misdirected needle may puncture the tubing and cause leaking of fluid out of the gastric banding system, which may eventually lead to reduced efficacy of the gastric band. In some scenarios, the entire gastric banding system may then need to be removed from the body or the physician may need to perform an operation to mend the punctured tube. 
     Exterior tubing shields have been used as one option to protect the tubing from puncturing from stray needles. However, tubing shields add bulk, which may in certain patients, reduce the biocompatibility of the tubing and/or reduce the comfort of the gastric banding system within the patient. 
     What is needed is an interior tubing protection system that can reduce the likelihood and/or severity of leaking while still maintaining the relatively less bulky tubing currently incorporated in gastric banding systems. 
     SUMMARY 
     Generally described herein are apparatus, systems and methods related to a stem insertable into the access port tubing for the prevention of fluid leaks. More particularly, the stem or stems may be larger than the interior diameter of the access port tubing thereby providing a fluid seal to keep the fluid within the access port tubing. However, these fluid seals might not be absolute and may still allow a certain small degree of leakage. In one embodiment, by including barbs which further press against the interior diameter of the access port tubing, the sealing of the fluid may be substantially improved. The stem itself, while impenetrable by a needle under normal application of force, may still allow for bend flexibility of the access port tubing by employing a ball and a socket joint for connecting to a next stem. In this manner, fluid leak prevention is improved while retaining the mobility of the access port tubing. 
     In one embodiment, provided is an access port for use with a gastric band for the treatment of obesity. The access port may comprise a housing enclosing a fluid reservoir, a conduit having a first end connected to the fluid reservoir and a bulbous second end, a tube having an inner surface defining a first pathway, a first end connected to the bulbous second end of the conduit and a second end connected to an inflatable portion of the gastric band. The tube further having a first stem guard located within the first pathway of the tube and configured to prevent a first needle from passing therethrough. The first stem guard may further include a first socket-shaped tail portion for receiving the bulbous second end of the conduit, a first ball-shaped head portion, a first shaft portion located between the first socket-shaped tail portion and the first ball-shaped head portion, the first shaft portion defining a second pathway for carrying fluid, and a first barb portion protruding from the first shaft portion and configured to extend into the inner surface of the tube. 
     In one embodiment, provided is a flexible tubing for carrying fluid between an access port and an inflatable portion of a gastric band. The flexible tubing may comprise a body configured to have a first end attachable to a bulbous end of a conduit of the access port and a second end attachable to the inflatable portion, the body having an inner surface defining a first pathway for carrying fluid, and a first stem guard located within the first pathway of the body and configured to prevent a needle from passing therethrough. The first stem guard may further include a first socket-shaped tail portion for receiving a bulbous second end of the conduit, a first ball-shaped head portion, a first shaft portion located between the first socket-shaped tail portion and the first ball-shaped head portion, the first shaft portion defining a second pathway for carrying fluid, and a first barb portion protruding from the first shaft portion and configured to extend into the inner surface of the body. 
     In one embodiment, provided is a needle stem guard located internally within a first pathway of a flexible tubing for the prevention of leaks. The needle stem guard may comprise a socket-shaped tail portion for receiving a bulbous conduit connected to a fluid reservoir of an access port, a ball-shaped head portion, a shaft portion located between the first socket-shaped tail portion and the ball-shaped head portion, the shaft portion defining a second pathway for carrying fluid, and a barb portion protruding from the shaft portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features, obstacles, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, wherein: 
         FIG. 1  illustrates a gastric banding system including an access port according to an embodiment of the present invention. 
         FIG. 2A  illustrates needle stick stem guards without barbs according to an embodiment of the present invention. 
         FIG. 2B  illustrates a potential leak path utilizing the needle stick stem guards without barbs of  FIG. 2A . 
         FIG. 3A  illustrates how the inclusion of barbs to needle stick stem guards may prevent a potential leak path according to an embodiment of the present invention. 
         FIG. 3B  illustrates needle stick stem guards with barbs according to an embodiment of the present invention. 
         FIG. 3C  illustrates a close-up, cross-sectional view of a portion of  FIG. 3A  according to an embodiment of the present invention. 
         FIG. 3D  illustrates an even closer view of a portion of  FIG. 3A  according to an embodiment of the present invention. 
         FIG. 3E  illustrates a stem guard for attaching to a connector of an access port housing according to an embodiment of the present invention. 
         FIG. 3F  illustrates a cross-sectional view of the stem guard of  FIG. 3E  according to an embodiment of the present invention. 
         FIG. 3G  illustrates a stem guard for attaching to another stem guard according to an embodiment of the present invention. 
         FIG. 3H  illustrates a cross-sectional view of the stem guard of  FIG. 3G  according to an embodiment of the present invention. 
         FIG. 4A  illustrates needle stick stem guards with barbs according to an embodiment of the present invention. 
         FIG. 4B  illustrates a close-up, cross-sectional view of a portion of  FIG. 4A  according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Apparatuses, systems and/or methods that implement the embodiments of the various features of the present invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate some embodiments of the present invention and not to limit the scope of the present invention. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. 
       FIG. 1  illustrates an implantable gastric banding system  105  used for the treatment of obesity. In the embodiment shown, a tube  125  and an access port  130  are used in the implantable gastric banding system  105 , including a gastric band  110  configured to form a loop around a portion of a stomach  120  of a patient  100  to form a stoma. The gastric band  110  is preferably wrapped around the cardia or esophageal junction of the stomach  120  to restrict the flow of food passing from the upper portions of the stomach  120  to the lower portions of the stomach  120 . The restricted flow of food enhances the satiety signals sensed by the patient  100 , which desirably reduces food consumption of the patient  100 , which aids the patient  100  in losing weight. 
     Over time, a physician may need to adjust the degree to which the gastric band  110  constricts the stomach. As such, the gastric band  110  may include an inflatable portion  115 , which comprises an inflatable cuff that wraps around the stomach  120  of the patient  100 . The inflatable portion  115  may be filled with fluid. The amount of fluid in the inflatable portion  115  defines the degree to which the gastric band  110  constricts the stomach  120  (e.g., a greater amount of fluid in the inflatable portion  115  will increase the constriction of the stomach  120 ). A physician may adjust the amount of fluid in the inflatable portion  115  via the access port  130 . 
     The access port  130  is preferably fixed subcutaneously within the body of the patient  100 , and is preferably fixed to body tissue including the interior muscle wall of the patient  100 . The tube  125  conveys fluid to and from the inflatable portion  115  via the access port  130 . One end of the tube  125  couples to the access port  130 , and the other end of the tube  125  couples to the inflatable portion  115  of the gastric band  110 . 
     A physician inserts a syringe needle  150  into the patient&#39;s body to access the access port  130 , and varies the amount of fluid in the inflatable portion  115  of the gastric band  110 . Generally, the physician must attempt to locate a septum  135  of the access port  130  to pass the syringe  150  needle through the septum  135 . The septum  135  must be penetrated by the syringe needle  150  to allow fluid to enter, or be removed from the access port  130 . The physician will typically palpate the area around the access port  130  to locate the septum  135 . 
     However, it may be difficult for the physician to properly locate the septum  135 , because the access port  130  may be covered by many layers of skin and/or fat. Accordingly, it is possible the physician may not properly locate the septum  135 , and may insert the syringe  150  needle in the wrong location. The physician may errantly contact a portion of the tube  125  proximal to the access port  130 . The syringe needle  150  may puncture the tube  125 , specifically the end of the tube  125  connected to the access port  130 , and may cause fluid to leak from the gastric banding system  105 . A surgical procedure may be necessary to repair the punctured tube  125 , or replace the entire gastric banding system  105 . 
     By incorporating an apparatus to guard the tube  125  from leaking fluid, this undesirable result may be avoided or prevented. 
       FIG. 2A  illustrates an access port system  200  having needle stick guard stems  230 ,  235 ,  240  deployed or positioned in an internal fluid pathway  225  to prevent the leaking out of fluid when a needle pricks or penetrates a flexible tubing  220  between an access port  205  and a gastric band (not shown). As shown, the needle stick guard stem  230  is connected to an access port connector  215 , which in turn, serves as a fluid conduit between an internal fluid reservoir  240  of the access port  205  and the rest of the gastric band. The needle stick guard stem  230  is attached to another needle stick guard stem  235 , which in turn is attached to the needle stick guard stem  240 . As these needle stick guard stems  230 ,  235 ,  240  are positioned inside the internal fluid pathway  225 , in one sense, they block or restrict the internal fluid pathway  225 . However, the needle guard stems  230 ,  235  and  240  include stem portions that are hollowed out to serve as fluid conduits while protecting the hollow interior from leakage caused by needle puncturing. In essence, the needle guard stems  230 ,  235  and  240  are able to fluidly couple the internal fluid reservoir  240  and the internal fluid pathway  225  by creating a substitute fluid pathway to allow fluid to travel from the fluid reservoir  240  to the internal fluid pathway  225 , and vice versa. 
     Advantageously, by utilizing a plurality of short needle stick guard stems (as opposed to one long one), flexibility of the tubing  220  may be maintained. As shown, the needle stick guard stem  240  leads to unprotected portions of the internal fluid pathway  225 . In practice, because physicians attempting to penetrate a septum  210  of the access port  205  are unlikely to miss by more than a few inches, additional needle stick guard stems may not be necessary. However, additional needle stick guard stems may be employed if desired. 
     Generally, the needle stick guard stems may prevent the needle from directly penetrating its shell and creating a large leak. However, the fact that these needle stick guard stems mainly incorporate physical pressure (e.g., pressing against and/or slightly stretching the outer diameter of the internal fluid pathway  225 ) to provide sealing renders the needle stick guard stems susceptible to allowing leaks from the joints (i.e., the connection point between two adjacent needle stick stem guards). 
       FIG. 2B  illustrates examples of a potential leakage path  255  and which may result when a misdirected needle  250  penetrates the area proximal to the stem. This potential leakage path  255  may allow fluid inside the gastric banding system to undesirably leak out potentially reducing the efficacy of the gastric banding system. 
     Accordingly, one or more barbs may be employed to prevent fluid passage from the joint to a puncture hole caused by a misdirected needle.  FIGS. 3A-3H  illustrates an embodiment having needle stick stem guards that are less susceptible to allowing leaks from joints. 
       FIG. 3A  illustrates a similar scenario as  FIG. 2B , where the misdirected needle  250  penetrates the area proximal to a needle stick guard stem  335 . However, due to the presence of a barb or protrusion  338 , fluid from the joint created by a head portion  339  and a corresponding tail portion  341  is blocked from traveling along the exterior of the needle stick guard stem  335  and out a hole caused by the needle  250 . Accordingly, the addition of a barb or protrusion  338  provides an advantageous benefit of leak prevention. 
       FIG. 3B  illustrates a perspective view of a portion of a gastric banding employing the features of  FIG. 3A . Here, needle stick guard stems  330 ,  335 ,  340  deployed or positioned in an internal fluid pathway  325  to prevent the fluid from leaking out of the gastric banding system when a needle pricks or penetrates the flexible tubing  320  connecting an access port  305  and a gastric band (not shown). Each of the needle guard stems  330 ,  335 ,  340  includes a barb or protrusion portion  333 ,  338  and  343 , respectively, directed to block a portion of the internal fluid pathway  325  in order to prevent fluid passage from a joint to a puncture hole caused by a misdirected needle in a manner similar to the illustration of  FIG. 3A  and the corresponding description, thereby increasing the leaking prevention capabilities. 
     In addition, the needle guard stems  330 ,  335 ,  340  are slightly larger than the inner diameter of the internal fluid pathway  325  of the flexible tubing  320  and therefore press against the flexible tubing  320  to create a fluid seal. 
       FIG. 3C  illustrates a close up, cross-sectional view of  FIG. 3A . As shown from left to right, an access port connector  315  defining a fluid conduit  350  may include a bulbous conduit head  345  connectable to the first needle guard stem  330 . More particularly, the head  345  fits into a tail portion  331  of the first needle guard stem  330 . The first needle guard stem  330 , in addition to the tail portion  331 , may include a shaft portion  332 , a barb portion  333  and a head  334  portion. The head portion  334  may fit into a tail portion  336  of the second needle guard stem  335  (in a manner that a ball may fit into a socket to create a flexible joint). The second needle guard stem  335  may also include a shaft portion  337 , a barb portion  338  and a head portion  339 . Similarly, the head portion of  339  of the second needle guard stem  335  fits into a tail portion  341  of the third needle guard stem  340  to create another flexible joint. The third needle guard stem  340  may also include a shaft portion  342 , a barb portion  343  and a head portion  344 . The stems  332 ,  337  and  342  may each be molded to include a cavity for transporting fluid, for example, internal fluid pathways  351 ,  352  and  353  for establishing a fluid path between the fluid conduit  350  and the internal fluid pathway  325 . 
     The addition of barbs  333 ,  338  and  343  at the joint areas proximal to the location of the heads  334 ,  338  and  344  are located advantageously to prevent fluid passage from the joint to a punctured hole. That is, the protruding aspects of the bulbous barb act as a shield to block the joint from being penetrated by a misdirected needle. In addition, since the barb portions  333 ,  338  and  343  significantly bulge out into the inner diameter of the tube, a better fluid seal is provided at the location of the barb portions  333 ,  338  and  343 . In this manner, a leak may be limited to only existing fluid between two adjacent barbs since additional fluid cannot flow past the barbs and out of the puncture hole. 
       FIG. 3D  further illustrate the relative diameters of a needle stick stem guard (e.g., needle stick stem guard  340 ) which serves to explain how fluid is passed between the fluid paths  325  and  353  while being blocked by barb portion  343  and how a fluid seal is created by a diameter  362  of the needle stick stem guard  340 . As shown in  FIG. 3C , the inner diameter of a tube  360  may be larger or equal to an inner diameter  361  of the fluid path  353 . However, the inner diameter  361  is less than the diameter  362  of the needle stick stem guard  340 . In this manner, any leaking of fluid as shown by arrow  371  is minimal. The barb portion  343  further seals and/or blocks the fluid shown by arrow  371  as it protrudes even deeper into the flexible tubing  320 . Accordingly, fluid may travel between fluid pathway  325  and  353  without leaking out of the pathway. 
       FIG. 3E  illustrates a close-up view of the first needle stem guard  330  and  FIG. 3E  illustrates a cross-sectional view of the first needle guard  330 . The fluid pathway of the first needle stem guard  351  is hidden from view in  FIG. 3D  (as it extends from the opening  370  of the head portion to the tail portion  331 ), but is revealed in  FIG. 3E . The first needle stem guard  330  as described above may include the tail portion  331  for receiving the head  345  of the connector  315 . At one end, the tail portion  331  may have an opening with a first diameter sized to fit the head portion  345  and may taper down to a relatively smaller diameter corresponding to portion of the shaft portion  332  (which may still be slightly larger than an inner diameter of the fluid pathway, for example, fluid pathway  325 ). The shaft portion  332  may lead to the barb portion  333  which bulges out beyond the outer diameter of the shaft portion  332 . On the other side of the barb portion  333  may be the head portion  334  which includes a hole  370  for allowing fluid to enter and travel along the fluid pathway  351 . 
     In one embodiment, the first needle guard  330  may be anywhere between about 0.5 centimeters to about 5 centimeters long as measured between the head portion  334  and the tail portion  331 . Preferably, the first needle stem guard  330  may be between about 2 to 4 centimeters long. 
     The first needle stem guard  330  may be constructed out of any suitable biocompatible material including, but not limited to, titanium, stainless steel, polysulfone, PPSU, PEEK from Solvay, UHMWPE from Ticona, and any combination thereof. 
       FIGS. 3G and 3H  illustrate an example of a stem guard other than the first needle stem guard  330  (e.g., stem guard  335  or  340 ). For ease of understanding, references will be made to the second needle stem guard  335  as attachable to the first needle stem guard  330 , but the characteristics are also applicable to the third needle stem guard  340  or any other stem guards that may be desirably added. As compared to the first needle stem guard  330 , the second needle stem guard  335  has a tail portion  336  configured to be a different shape and size. The reason for the difference is because the two tails,  331  and  336 , respectively, may receive head that are shaped differently. While the tail  331  is shown to be larger to accommodate for the larger connector head  345 , other variations are possible (e.g., where the connector head is actually smaller than a head of the stem guards). Indeed, besides the shape and size of the tail portion  336 , the second stem guard  335  is virtually identical in size, functionality and material as the first stem guard  330 . In other words, the tail portion  336  of the second needle stem guard  375  may have an opening with a first diameter sized to fit the head  334  of the first needle stem guard  330  and may taper down to a relatively smaller diameter corresponding to the portion of the shaft portion  337  (which may still be slightly larger than an inner diameter of the fluid pathway, for example, fluid pathway  325 ). The shaft portion  337  may lead to the barb portion  338  which bulges out beyond the diameter of the shaft portion  337 . On the other side of the barb portion  338  may be the head portion  339  which includes a hole  375  for allowing fluid to enter and travel along the fluid pathway  352  and through the fluid pathway  351  of the first needle stem guard  330 . The dimensions of the shaft portion  337 , the barb portion  338  and the head portion  339  may, in one embodiment, be identical to the dimensions of the shaft portion  332 , the barb portion  333  and the head portion  334  of the first needle stem guard  330 . Indeed, identical dimensioning of needle stem guards may allow for cheaper manufacturing and improved compatibility as the needle stem guards all couple to at least one other needle stem guard to produce a protected fluid path. 
     Furthermore, the shape of the head of one needle stem guard is configured to be received by the shape of the tail of an adjacent needle stem guard in order to provide the “ball-and-socket” functionality and thereby allow pivoting of the respective, adjacent needle stem guards to maintain flexibility of the tubing within which the needle stem guards are positioned. 
     In newly designed access ports and/or other appropriate access ports, the connector leading out of the access port housing (e.g., the access port connector  315 ) may be designed to have a head that is shaped and dimensioned similarly to the head of the first needle stem guard, the second needle stem guard, the third needle stem guard, and so forth. By conforming the head shape and dimension of the connector to be the same as the needle stem guards, all needle stem guards may be identical. In other words, this will eliminate the need for the first needle stem guard (e.g., first needle stem guard  335 ) interfacing with the connector (e.g., connector  315 ) to include a differently shaped and/or dimensioned tail. 
     For example,  FIGS. 4A and 4B  illustrate an access port connector  415  having a head shaped and dimensioned to be similar to the head shape and dimension of needle stem guards  430 ,  435 , and  440 . In this embodiment, manufacturing of only one interchangeable type of needle stem guard is possible. 
       FIG. 4A  illustrates one embodiment of needle stick guard stems  430 ,  435 ,  440  deployed or positioned in an internal fluid pathway  425  to prevent the leaking out of fluid when a needle pricks or penetrates a flexible tubing  420  between an access port  405  and a gastric band (not shown). Each of the needle guard stems  430 ,  435 ,  440  may be identical. Furthermore, each of the needle guard stems  430 ,  435 ,  440  includes a barb or protrusion portion  433 ,  438  and  443 , respectively, directed to block a portion of the internal fluid pathway  425  in order to prevent fluid passage from a joint to a puncture hole caused by a misdirected needle, thereby increasing the leaking prevention capabilities. 
     In addition, the needle guard stems  430 ,  435 ,  440  are slightly larger than the inner diameter of the internal fluid pathway  425  of the flexible tubing  420  and therefore press against the flexible tubing  420  to create a fluid seal. 
       FIG. 4B  illustrates a close-up, cross-sectional view of  FIG. 4A . As shown from left to right, an access port connector  415  defining a fluid conduit  450  may include a head  445  connectable to the first needle guard stem  430 . More particularly, the head  445  fits into a tail portion  431  of the first needle guard stem  430 . The first needle guard stem  430 , in addition to the tail portion  431 , may include a shaft portion  432 , the barb portion  433  and a head  434  portion. The head portion  434  may fit into a tail portion  436  of the second needle guard stem  435  (in a manner that a ball may fit into a socket to create a flexible joint). The second needle guard stem  435  may also include a shaft portion  437 , the barb portion  438  and a head portion  439 . Similarly, the head portion  439  of the second needle guard stem  435  fits into the tail portion  441  of the third needle guard stem  440  to create another flexible joint. The third needle guard stem  440  may also include a shaft portion  442 , the barb portion  443  and a head portion  444 . The shaft portions  432 ,  437  and  442  may each be molded to include a cavity for transporting fluid through, for example, internal fluid pathways  451 ,  452  and  453  for establishing a fluid path between fluid conduit  450  and the internal fluid pathway  425 . 
     The addition of the barb portions  433 ,  438  and  443  at the joint areas proximal to the location of the heads  434 ,  439  and  444  are located advantageously to prevent fluid passage from the joint to a punctured hole. For example, the barb portions  433 ,  438  and  443  function to provide protection to the joint from a misdirected needle. That is, the protruding aspects of the barb act as a shield to block the joint from being penetrated by a misdirected needle. In addition, since the barb portions  433 ,  438  and  443  significantly bulge out into the inner diameter of the tube, a better fluid seal is provided at the location of the barb portions  433 ,  438  and  443 . In this manner, a leak may be limited to only existing fluid between two adjacent barbs since additional fluid cannot flow past the barbs and out of the puncture hole. 
     Certain embodiments have been disclosed to clarify the concepts including the above structural configurations. However, one skilled in the art will recognize that an endless number of implementations may be performed with the concepts herein. For example, the tube may be a catheter and may be used in other applications which require transferring fluid or gas. 
     Unless otherwise indicated, all numbers expressing quantities of ingredients, volumes of fluids, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. 
     The terms “a,” “an,” “the” and similar referents used in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention. 
     Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims. 
     Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 
     Furthermore, certain references have been made to patents and printed publications throughout this specification. Each of the above-cited references and printed publications are individually incorporated herein by reference in their entirety. 
     Specific embodiments disclosed herein may be further limited in the claims using consisting of or and consisting essentially of language. When used in the claims, whether as filed or added per amendment, the transition term “consisting of” excludes any element, step, or ingredient not specified in the claims. The transition term “consisting essentially of” limits the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic(s). Embodiments of the invention so claimed are inherently or expressly described and enabled herein. 
     In closing, it is to be understood that the embodiments of the invention disclosed herein are illustrative of the principles of the present invention. Other modifications that may be employed are within the scope of the invention. Thus, by way of example, but not of limitation, alternative configurations of the present invention may be utilized in accordance with the teachings herein. Accordingly, the present invention is not limited to that precisely as shown and described.