ELECTROCEUTICAL DRESSING FOR WOUND CARE
20230166101 · 2023-06-01
Inventors
- Shaurya Prakash (Columbus, OH)
- Vishwanath Subramaniam (Westerville, OH, US)
- Traci WILGUS (Dublin, OH, US)
- Paul STOODLEY (Columbus, OH, US)
- Daniel WOZNIAK (Columbus, OH, US)
- Prashanth Mohana SUNDARAM (Columbus, OH, US)
- Rachel HEALD (Laurel, MD, US)
- Gurleen VILKHU (Lewis Center, OH, US)
- Kavya NARAYANAN (Dublin, OH, US)
Cpc classification
A61N1/0476
HUMAN NECESSITIES
International classification
Abstract
Electroceutical dressings having at least three electrodes that are used for prevention and mitigation of biofilm and bacterial infection by an applied electric current are provided. Methods of making the dressings and methods of applying an electric current to promote the wound healing process are also disclosed.
Claims
1. An electroceutical dressing comprising: a substrate having two sides, wherein one of the sides is a wound-facing side and a second side opposite the wound-facing side; three or more electrodes positioned on the wound-facing side of the substrate, said electrodes comprising at least a conductive anode, a conductive cathode, and a conductive reference node, wherein each of three or more electrodes are configured to be in at least partial contact with a wound when the electroceutical dressing is placed on the wound; and an energy source having a positive terminal and a negative terminal, wherein the positive terminal is configured to connect to one of the conductive anode and/or the conductive cathode, and the negative terminal is configured to connect to an other of the conductive cathode and/or the conductive anode when the electroceutical dressing is placed on the wound, wherein when connected to the conductive anode and the conductive cathode the energy source induces an electrical current to flow through the wound.
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10. The electroceutical dressing of claim 1, further comprising one or more sensors comprised of one or more of a transepidermal water loss probe, an electrical impedance sensor, and an eddy current sensor, wherein a change in sensed electrical characteristics of the electrical impedance sensor and the eddy current sensor are used to estimate healing of the wound.
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15. The electroceutical dressing of claim 1, wherein a change in electrical characteristics of the energy source and/or the three or more electrodes over time is used to estimate healing, wherein a change in electrical characteristics of the energy source and/or the three or more electrodes includes a change in resistance and/or impedance between any two of the electrodes, and/or a change in current and/or voltage of the energy source.
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21. The electroceutical dressing of claim 1, further comprising an insulating material, wherein the energy source is substantially insulated from at least one of the conductive anode and the conductive cathode using the insulating material, wherein the insulating material is substantially an electrical insulator when in its solid form but when moistened forms an electrically-conductive solution, wherein the insulating material comprises NaCl, KCl, sugar, glucose, or any other material that presents electrically isolating properties in the solid phase and upon exposure to a solvent dissolves entirely or in-part to generate an electrically conducting solution.
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30. The electroceutical dressing of claim 1, wherein the conductive anode is larger than the conductive cathode.
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32. The electroceutical dressing of claim 30, wherein the conductive anode is conformed to a shape such that it substantially covers the wound.
33. The electroceutical dressing of claim 1, wherein a size and shape of the electroceutical dressing is determined by at least one of wound size, wound shape, and location of the wound.
34. The electroceutical dressing of claim 1, wherein a size and shape of at least one of the conductive anode and the conductive cathode is determined by at least one of wound size, wound shape, and location of the wound.
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43. The electroceutical dressing of claim 1, wherein the energy source comprises at least two electrodes in a spaced pattern on an insulating substrate and the at least two electrodes are comprised of a biocompatible reduction/oxidation reaction materials such that a voltage differential is created between the at least two electrodes.
44. The electroceutical dressing of claim 43, wherein the energy source comprises a plurality of electrodes in a spaced pattern on the insulating substrate wherein a first subset of the plurality of electrodes are connected in electrical series and a second set of the plurality of electrodes are connected in a separate electrical series and the plurality of electrodes are comprised of a biocompatible reduction/oxidation reaction material such that a voltage differential is created between the first subset of the plurality of electrodes connected in electrical series and the second subset of the plurality of electrodes connected in electrical series.
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52. The electroceutical dressing of claim 1, further comprising a barrier that substantially covers the second side of the substrate, said barrier configured to maintain a desired moisture level of the wound.
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54. The electroceutical dressing of claim 1, further comprising a current-limiting element, wherein the current limiting element limits the electrical current flowing through the wound to a desired range.
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59. The electroceutical dressing of claim 1, further comprising a voltage indicator, wherein the voltage indicator indicates voltage being provided by the energy source, and/or a current indicator, wherein the current indicator indicates a presence and/or a magnitude of the electrical current flowing through the wound.
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61. The electroceutical dressing of claim 1, wherein at least one of the three or more electrodes are comprised of a biocompatible reduction/oxidation reaction material.
62. The electroceutical dressing of claim 61, wherein the electrical current flowing through the wound inhibits formation of a biofilm within the wound, at least partially disrupts a biofilm growing within the wound, at least partially destroys sessile bacteria within the wound, and/or at least partially destroys planktonic bacteria within the wound.
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71. A method of assembling an electroceutical dressing, comprising: applying a layer of conductive material to an insulated base substrate to form at least one electrode pair and a reference electrode on the insulated base substrate, wherein the pair of electrodes comprise a conductive anode and a conductive cathode that are electrically insulated from one another and the reference electrode is insulated from the conductive anode and the conductive cathode, wherein an energy source is connected to the at least one electrode pair, wherein the energy source induces an electrical current to flow from the conductive anode, through a wound, to the conductive cathode, wherein potential between the anode and the reference electrode is monitored and/or controlled to produce HOCL in the wound.
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80. The method of claim 71, wherein the energy source connected to the at least one electrode pair comprises a flexible fabric battery and the flexible fabric battery comprises a plurality of electrodes in a spaced pattern on a fabric substrate, wherein the energy source comprises the plurality of electrodes in a spaced pattern on the fabric substrate and a first subset of the plurality of electrodes are connected in electrical series and a second set of the plurality of electrodes are connected in electrical series and the plurality of electrodes are comprised of a biocompatible reduction/oxidation reaction material such that a voltage differential is created between the anode and the cathode.
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86. The method of claim 71, further comprising an insulating material, wherein the energy source is substantially insulated from at least one of the conductive anode and the conductive cathode using the insulating material, wherein the insulating material comprises NaCl, KCl, sugar, glucose, or any other material that presents electrically isolating properties in the solid phase and upon exposure to a solvent dissolves entirely or in-part to generate an electrically conducting solution.
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88. The method of claim 71, further comprising providing a current-limiting element, wherein the current limiting element limits the electrical current flowing from the conductive anode, through the wound, to the conductive cathode to a desired range.
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92. The method of claim 71, further comprising providing one or more sensors, wherein the one or more sensors measure impedance through the wound or eddy current in the wound, which is used to determine healing of the wound.
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Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:
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DETAILED DESCRIPTION
[0029] In the United States, 6.5 million patients are affected by chronic wounds, sometimes complicated by infection. If the bacteria form a biofilm at the wound site, treatment of the infection becomes significantly more difficult. Biofilm bacteria are 500 to 5,000 times more resistant to antibiotic medications than the non-biofilm bacteria. Previous studies have shown that the presence of direct electric current through the biofilm enhances the activity of various antibiotics against biofilm-forming bacterial strains such as Pseudomonas aeruginosa and Staphylococcus epidermidis. This behavior has been referred to as the electro-bactericidal effect.
[0030] Disclosed herein are electroceutical wound care dressings and methods of using the electroceutical wound care dressings for wound treatment in humans and animals. The electroceutical wound care dressings can be used to apply an electric current through a wound to aid in bacterial infection prevention and destruction. These dressings can provide a functional antimicrobial and antibiofilm barrier.
[0031] Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.
[0032] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes¬ from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
[0033] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
[0034] Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal embodiment. “Such as” is not used in a restrictive sense, but for explanatory purposes.
[0035] Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods.
[0036] The present methods and systems may be understood more readily by reference to the following detailed description of preferred embodiments and the Examples included therein and to the Figures and their previous and following description.
[0037] In one aspect, disclosed are wound care dressings that include an electrode assembly and an electric current generating and control assembly. The electrode assembly can be used for applying an electric current for wound healing. The electric current generating and control assembly can be used to control and vary the electric current intensity during the wound healing period. The wound care dressings can provide antimicrobial and antibiofilm effects, which aid wound healing and tissue regeneration.
[0038]
[0039] The anode 106, the cathode 108 and the conductive reference electrode 112 are electrically insulated from one another. The energy source 110 induces a voltage differential between the conductive anode 106 and conductive cathode 108, which causes an electrical current (I) to flow from the conductive anode 106, through the wound 102 (represented here as an electrical resistor), to the conductive cathode 108.
[0040] In some instances the reference electrode 112 is connected to a source with a known potential. For example, the reference electrode 112 may be connected to an electrical ground. The potential between the anode 106 and/or the cathode 108 and the reference electrode 112 can be determined when the reference electrode 112 is connected to the source having known potential. In this way, a potential difference between the conductive anode 106 and/or the conductive cathode 108 and the conductive reference node can be measured and the energy source can be used to maintain that potential difference at or above a desired potential to generate hypochlorous acid in the wound. For example, the desired potential difference may be 1.14 volts with respect to a Ag/AgCl reference electrode, or greater, which is a potential difference that is known to produce HOC1 electrochemically.
[0041]
[0042] Also, though
[0043] Generally, in regard to the substrate 104, it is comprised of material that is substantially electrically insulating. For example, the substrate 104 may be comprised of silk, polyester, and any material that has ability for printing a desired geometry and is compatible with a wound environment (i.e., does not occlude the wound for transport of essential fluids including oxygen) including polymeric substrates common to the medical industry like Polydimethylsiloxane (PDMS) and the like. In one embodiment of the dressings 100, the substrate 104 is comprised of silk and the silk comprises Habotai silk. In other embodiments the substrate 104 may be comprised of semiconductive materials or may have conductive elements within the substrate. For example, at least one of the conductive anode 106, the conductive cathode 108, or the reference node 112 may be woven into the substrate 104. In one specific example, at least one of the conductive anode 106, the conductive cathode 108, or the reference node 112 comprise a conductive silver material woven into a Habotai silk substrate 104. In one non-limiting example, an electrical current may be circulated through the conductive or semiconductive element of the substrate 104 in parallel to the current that flows from the conductive anode 106, through the wound 102, to the conductive cathode 108. The current through the substrate may create an electrical field that can facilitate healing of the wound. Generally, the substrate 104 or at least the wound side portion of the substrate 104 is sterile. Non-limiting examples of substrate 104 thickness include 10 .Math.m - 1 mm or 10 .Math.m -0.5 mm.
[0044] In other examples, at least one of the conductive anode 106, the conductive cathode 108, or the reference node may be printed on the substrate using conductive printing techniques. For example, at least one of the conductive anode 106, the conductive cathode 108, or the reference node 112 may be printed on the substrate 104 using screen-printing techniques, using a (conductive) ink-jet printer, and the like. It is to be appreciated that any other deposition or incorporation methods may be used to form the conductive anode 106, conductive cathode 108, and the reference node 112 on or within the substrate 104.
[0045] Generally, the conductive anode 106, the conductive cathode 108 and the reference node 112 are comprised of biocompatible electrically-conductive materials. Examples of such materials include silver, silver chloride, silver compounds, gold, gold compounds, platinum, platinum compounds, and/or binary alloys of platinum, nickel, cobalt or palladium with phosphorus, or binary alloys of platinum, nickel, cobalt or palladium with boron, and the like. Non-metallic materials are also contemplated for electrode formation such as conductive polymers and the like. Conductive polymers can include, but are not limited to, polyaniline, polythiophene, polypyrrole, polyphenylene, poly(phenylenevinylene), and the like.
[0046] The conductive anode 106, the conductive cathode 108, and the reference node 112 may be of any size and/or shape. Generally; however, as shown in
[0047] Referring to
[0048] As shown in
[0049] In one aspect, the energy source 110 comprises a battery, which may include any number of cells connected in either series and/or parallel. In one aspect, the energy source 110 may comprise a battery paired with an inverter to create an AC source or it may be an AC source transformed to the desired voltage. In one exemplary embodiment, the energy source 110 connected to the at least one electrode pair comprises an energy harvesting device that creates the voltage differential between the anode 106 and the cathode 108. For example, the energy harvesting device may be of the type that creates the voltage differential between the anode 106 and the cathode 108 based on movement of a subject to whom the electroceutical dressing is applied. Further, the energy source 110 may at least in part use a galvanic reaction between the anode 106, the wound 102, and the cathode 108 to create a voltage differential between the anode 106 and the cathode 108, which results in the electrical current flowing from the conductive anode 106, through the wound 102, to the conductive cathode 108.
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[0052] In one aspect, as shown in
[0053] The barrier 216 can control the rate of moisture evaporation from the substrate and/or the wound 102, and also function as a physical barrier to the penetration of microbes from the surrounding environment. The barrier 216 can be a film, fabric or foam. Some preferred materials include, but are not limited to, polyurethanes, polyolefins such as linear low density polyethylene, low density polyethylene, ethylene vinyl acetate, vinylidene, chloride copolymer of vinyl chloride, methyl acrylate or methyl methacrylate copolymers and combinations thereof. A preferred polymeric material is polyurethane, either as a film or as a polyurethane foam. The polyurethane may be an ester or ether based polyurethane. Materials suitable for a foam moisture regulation layer can be any semi-permeable or impermeable natural or synthetic compound including, but not limited to, rubber, silicon, polyurethane, polyethylene polyvinyl, polyolefin, hydrogels, or combinations thereof.
[0054] Alternatively, the barrier 216 may be a transparent elastomer film for visual inspection of the moisture status of the substrate 104. The film can have a thickness from 10 .Math.m to 100 .Math.m. The barrier 216 may have an MVTR of from about 300 to about 5,000 grams/meter2/24 hours, preferably from about 800 to about 2,000 grams/meter2/24 hours. The barrier 216 can be laminated to the substrate 104 by methods well recognized in the art.
[0055] The electroceutical dressing 100 can optionally include one or more therapeutic agents. Exemplary therapeutic agents include, but are not limited to, growth factors, analgesics (e.g., an NSAID, a COX-2 inhibitor, an opioid, a glucocorticoid agent, a steroid, or a mineralocorticoid agent), antibiotics, antifungals, anti-inflammatory agents, antimicrobials (e.g., chlorhexidine-, iodine-, or silver- based agents), antiseptics (e.g., an alcohol, a quaternary ammonium compound), antiproliferative agents, emollients, hemostatic agents, procoagulative agents, anticoagulative agents, immune modulators, proteins, vitamins, and the like.
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[0057] Optionally, other embodiments of the electroceutical dressing 100 may include one or more sensors. To control electroceutical actuation for HOC1 generation, it is desired to know at what stage of healing the wound is, at a given point in time (with respect to the healing stages). The current standard method that exists to monitor wound healing is a visual inspection of the wound by the clinician. This method is very less deterministic and varies from person to person. Hence, a quantifiable parameter is desired that can be monitored in real time and does not require removal of the dressings frequently for inspection. To monitor both the biochemical and physical states across distinct regimes of angiogenesis, inflammation control, and wound closure, one or more sensors can be integrated into embodiments of the electroceutical dressing, including: (i) miniaturized existing TEWL (transepidermal water loss) probes (measures temperature and humidity to estimate wound evaporation rate); (ii) electrical impedance and/or eddy current sensors to provide a detailed ‘geographical map’ of the wound bed electrical properties in real time. TEWL measurements are a reliable, existing method to verify the restoration skin barrier function and also serve as a measure of validation of the remaining sensors that may be integrated into an embodiment of the electroceutical dressing. The impedance and eddy current sensors rely on data that shows that as infected, burn wounds healed with application of an embodiment of the disclosed electroceutical dressing, the electrical properties of the wound tissue evolved in time (see
[0058] In addition, to avoid the frequent removal of the dressings, the sensors may use wireless communications (see
[0059] n one aspect, the one or more sensors may comprise an electrical impedance spectroscopy (EIS) probe that senses impedance through the wound 102. In another aspect, the sensor may comprise an eddy current probe. As noted herein, the measured impedance through the wound 102 can be used to detect wound healing. For example, as shown in
[0060]
[0061] The electroceutical dressings disclosed herein can be fabricated by various methods. The electrodes can be fabricated from the conductive materials disclosed herein.
[0062] In an exemplary embodiment, the electroceutical dressing fabrication process can begin with applying the conductive electrodes 106, 108, 112 to the substrate 104. This step may involve printing techniques such as screen-printing or using an ink-jet printer, among other methods. For example, applying the electrodes may comprise screen printing Ag/AgCl ink (cathode) and a paste of zinc (Zn) powder and poly (vinyl alcohol) (PVA) in water (anode) on a silk fabric.
[0063] Also, in certain embodiments, electrodes 106, 108, 112 can be fabricated by stamping a solution of conductive polymer or precursor(s) thereof onto the substrate 104. Any of a variety of known methods for stamping can be used to fabricate the electrodes. In certain embodiments, electrodes 106, 108, 112 can be fabricated using a capillary micromolding technique and/or apparatus. In certain embodiments, electrodes, 108, 112 can be fabricated by printing conductive polymer and/or prepolymer directly onto an appropriate substrate 104. In one example an ordinary laser printer is used in combination with specially formulated ink to form a patterned conductive polymer film. An appropriate ink formulation can comprise a conductive polymer and/or prepolymer thereof. Additionally, such an ink may optionally comprise a binder, a surfactant, and/or an oxidizing agent such as ferric ethylbenzenesulfonate. In one example, a substrate 104 coated with an appropriate ink is exposed to excess monomer vapor thereby developing the image in the regions containing oxidizing agent. This results in a conductive polymer image. In certain embodiments, a laser printer can be used to print a negative image of an electrode. The negative can then be dipped into a conductive polymer deposition/coating system. This results in polymer coating both the negative image and the exposed substrate 104. Then the image can be developed by removing the toner. In one example, a negative image of an interdigitated electrode (IDE) can be printed on an ordinary overhead transparency using a laser printer. The conductive polymer can then be formed in situ. In certain embodiments, electrodes can be fabricated photolithographically.
[0064] The layers of disclosed electroceutical dressings may or may not be attached to each other or can be provided as a component of another structure. For example, an electrode including a patterned conductive layer on a base substrate can be applied directly to the affected site, such as a wound. The energy source can be integral with or supplied separately from the electrode assembly of the electroceutical dressings.
[0065] The disclosed electroceutical dressings can be used to treat wounds of an animal or human subject. The appropriate aspect of the wound dressing can be selected and positioned on the wound, with the electrodes in direct contact or indirect contact with the wound.
[0066] In one aspect, disclosed is a method of treating or preventing a bacterial infection (e.g., a biofilm infection) in a wound, the method including applying a therapeutically effective amount of an electric current to the wound. The electric current can be applied to the wound via a electroceutical dressing as disclosed herein. The electroceutical dressing can include an anode and a cathode that are substantially in contact with the wound or its exudate such that an electric current flows through the wound. As a non-limiting example, the voltage potential between the anode and the cathode may be from 1-10 volts. Potential between the anode 106 and the reference node 112 can be monitored to ensure optimal HOCL generation in the wound. The time of treatment may range from hours to days. The electroceutical dressing can be applied, for example, within 4-6 hours of injury to prevent biofilm formation. The electroceutical dressing can be applied, for example, after biofilm formation (e.g., 7 days after injury) to treat a biofilm infection. The method may reduce the bacterial load by > 90% over a period of 4 weeks. For example, the starting bacterial load may be 10.sup.5-10.sup.8 colony forming units (cfu)/ml, where 10.sup.5 is the clinical infection threshold, and the method of treatment using the electroceutical dressing reduces the bacterial load to below the clinical threshold (e.g. at or below 10.sup.1-10.sup.2 cfu/ml) in the wound.
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[0068] Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications, including without limitation those relating to the chemical structures, substituents, derivatives, intermediates, syntheses, compositions, formulations, or methods of use of the invention, may be made without departing from the spirit and scope thereof.
[0069] While the methods and systems have been described in connection with preferred embodiments and specific examples, it is not intended that the scope be limited to the particular embodiments set forth, as the embodiments herein are intended in all respects to be illustrative rather than restrictive.
[0070] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification.
[0071] Throughout this application, various publications may be referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which the methods and systems pertain and to illustrate improvements over the present state of the art in claimed invention.
[0072] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.