Disclosure of Invention
Aiming at the problem of poor lubricating capability in the prior art, the invention aims to provide a bone trabecular metal total ankle joint prosthesis.
In order to solve the problems, the invention adopts the following technical scheme.
A bone trabecular metal total ankle joint prosthesis, which comprises a talus connecting frame, wherein a joint device is fixedly arranged at the top of the talus connecting frame, and a tibia connecting part is fixedly arranged at the top of the joint device;
The joint device comprises a fixed seat, a hinge groove is formed in the fixed seat, a hinge ball is movably mounted in the hinge groove, the bottom of the hinge ball is connected with the top of the talus connecting frame, a wear-resistant ceramic gasket is fixedly connected in the hinge groove, the inner side of the wear-resistant ceramic gasket is connected with the outer surface of the hinge ball, self-lubricating mechanisms are arranged on the outer surface of the hinge ball at equal intervals, linear guide holes are formed in the hinge ball at equal intervals, and the inner ends of the linear guide holes are communicated with the inner parts of the self-lubricating mechanisms.
Optionally, the equidistant rotation of surface upper end of articulated ball is connected with lubricated ball, the outside of lubricated ball is laminated with the inner wall of wear-resisting ceramic gasket and is connected, wear-resisting ceramic gasket comprises wear-resisting zirconia ceramic material.
Optionally, the self-lubricating mechanism comprises an elastic bag body, the elastic bag body is uniformly and annularly arranged and fixedly connected to the lower end of the outer surface of the hinged ball, the outer bottom and the inner bottom of the elastic bag body are fixedly connected with one-way valves, the output end of the one-way valve positioned at the outer side is communicated with the inner part of the elastic bag body, the output end of the one-way valve positioned at the inner end is communicated with the input end of the linear guide hole, and the elastic bag body is made of polycarbonate polyurethane.
Optionally, the tibia connecting portion comprises a connecting main pipe, a tibia connecting frame is fixedly installed at the top of the connecting main pipe, the connecting main pipe is fixedly connected to the top of the fixing seat, and outer macropores are formed in the outer surface of the connecting main pipe at equal intervals.
Optionally, inner micropores are formed in the connecting main pipe at equal intervals on the inner wall of the outer macropores of the ring, and the aperture of the outer macropores is larger than that of the inner micropores.
Optionally, microspheres are arranged in the micropores of the inner layer, and bone morphogenetic proteins and vascular endothelial growth factors are loaded in the microspheres.
Optionally, the bottom both sides fixedly connected with mounting bracket of talus link, the mounting hole has been seted up to the lower extreme of mounting bracket.
Optionally, the outer surfaces of the connecting main pipe, the tibia connecting frame, the hinging ball and the talus connecting frame are all provided with an antibacterial composite coating, and the antibacterial composite coating is a coating doped with silver nano particles or quaternary ammonium salt compounds in the HA coating.
Compared with the prior art, the technical scheme provided by the invention has at least the following beneficial effects:
In the scheme, the ankle joint prosthesis is characterized in that the joint device is characterized in that the hinge ball can freely rotate in the hinge groove of the fixing seat, the device can be adapted to the ankle joint of a human body, the rotation angle is adjusted in a self-adaptive mode, the wear-resistant ceramic gasket is attached to the hinge ball, the wear resistance is greatly improved, the lubricating balls arranged at the outer end of the hinge ball at equal intervals provide self-lubrication, particularly, the elastic bag body is matched with the one-way valve, when the hinge ball rotates, the fixing seat extrudes the elastic bag body, so that tissue lubricating liquid is sucked from the outside through a piston pumping function, and is uniformly conveyed to the surfaces of the hinge ball and the wear-resistant ceramic gasket through the linear guide holes, so that the lubricating property is improved in an omnibearing mode, the wear is reduced, and the smooth operation of the joint is ensured;
In the ankle joint prosthesis application, the tibial connecting part plays a key role, a tibial connecting frame connected with the top of a main pipe is ensured to be firmly connected with tibia, the main pipe is fixedly arranged at the top of a fixed seat to strengthen the stability of the whole structure, the outer layer macropores of the outer surface of the main pipe with the diameter of 500-800 mu m are beneficial to bone tissue ingrowth and enhance the anchoring effect of the prosthesis, the inner layer micropores with the diameter of 100-200 mu m are increased in surface area, the absorption growth factors support vascularization, PLGA microspheres loaded with BMP-2 and VEGF in the micropores are controlled by controlling the degradation rate of the microspheres, the growth factors are continuously released, osteoblast differentiation and angiogenesis are directionally activated to form a synergistic effect of 'bone-blood vessel synchronous growth', the bone healing is greatly accelerated, and the integration of the prosthesis and tibia is enhanced;
The mounting frames and the lower mounting holes on the two sides of the bottom of the talus connecting frame are conveniently and firmly connected with the talus to ensure the structural and functional continuity of the whole ankle joint prosthesis, and the antibacterial composite coating coated on the outer surfaces of the connecting main pipe, the tibia connecting frame, the hinge ball and the talus connecting frame HAs strong antibacterial performance no matter the HA coating is doped with 0.5-1wt% of silver nano particles or adopts quaternary ammonium salt compounds, can effectively inhibit bacterial breeding, greatly reduce postoperative infection risk, and provide firm and powerful guarantee for long-term stable work after prosthesis implantation and physical health of patients.
Drawings
The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.
FIG. 1 is a schematic perspective view of the present invention;
FIG. 2 is a schematic diagram of a front view of the present invention in a separated state;
FIG. 3 is a schematic view showing a separated bottom view structure of the present invention;
FIG. 4 is a schematic view of a tibial connection of the present invention;
FIG. 5 is a schematic view of the talar link and articulating ball configuration of the present invention;
FIG. 6 is a schematic view of the internal structure of the articulating ball of the present invention;
FIG. 7 is a schematic cross-sectional structural view of the outer macropores, inner micropores and microspheres of the present invention;
FIG. 8 is an enlarged schematic view of the structure of FIG. 4A according to the present invention;
FIG. 9 is an enlarged schematic view of the structure of FIG. 6B according to the present invention;
fig. 10 is an enlarged view of fig. 7 at C.
[ Reference numerals ]
1. A talar connection;
2. The device comprises a joint device, a fixing seat, a 22, a hinge groove, a 23, a hinge ball, a 24, a wear-resistant ceramic gasket, a 25 and a linear guide hole, wherein the joint device is arranged on the fixing seat;
26. 261, elastic bag body 262, one-way valve;
27. Lubricating the balls;
3. The tibia connecting part is 31, a connecting main pipe, 32, a tibia connecting frame, 33, an outer layer big hole, 34, an inner layer micropore, 35 and a microsphere;
4. And 5, an antibacterial composite coating.
Specific structures and devices are labeled in the drawings to enable clear implementation of embodiments of the invention, but this is merely illustrative and is not intended to limit the invention to the specific structures, devices and environments that may be modified or adapted by those of ordinary skill in the art, based on the specific needs.
Detailed Description
The invention will now be described in detail with reference to the drawings and to specific embodiments. While the invention has been described herein in detail in order to make the embodiments more detailed, the following embodiments are preferred and can be embodied in other forms as well known to those skilled in the art, and the accompanying drawings are only for the purpose of describing the embodiments more specifically and are not intended to limit the invention to the specific forms disclosed herein.
It should be noted that references in the specification to "one embodiment," "an example embodiment," "some embodiments," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the relevant art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
Generally, the terminology may be understood, at least in part, from the use of context. For example, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in a singular sense, or may be used to describe a combination of features, structures, or characteristics in a plural sense, depending at least in part on the context. In addition, the term "based on" may be understood as not necessarily intended to convey an exclusive set of factors, but may instead, depending at least in part on the context, allow for other factors that are not necessarily explicitly described.
It is to be understood that the meaning of "on," "above," "over" and "above" in the present invention should be read in the broadest manner so that "on" means not only "directly on" but also includes "on" something with intervening features or layers therebetween, and "on" or "above" means not only "on" or "over" but also may include the meaning of "on" or "over" it without intervening features or layers therebetween.
Furthermore, spatially relative terms such as "under," "below," "lower," "above," "upper," and the like may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented and the spatially relative descriptors used herein may similarly be interpreted accordingly.
As shown in fig. 1 to 10, an embodiment of the present invention provides a bone trabecular metal total ankle joint prosthesis, which comprises a talar connecting frame 1, wherein a joint device 2 is fixedly installed at the top of the talar connecting frame 1, and a tibia connecting part 3 is fixedly installed at the top of the joint device 2; the joint device 2 comprises a fixed seat 21, a hinge groove 22 is arranged in the fixed seat 21, a hinge ball 23 is movably arranged in the hinge groove 22, the bottom of the hinge ball 23 is connected with the top of the talus connecting frame 1, a wear-resistant ceramic gasket 24 is fixedly connected in the hinge groove 22, the inner side of the wear-resistant ceramic gasket 24 is connected with the outer surface of the hinge ball 23, a self-wetting mechanism 26 is arranged on the outer surface of the hinge ball 23 at equal intervals, linear guide holes 25 are arranged in the hinge ball 23 at equal intervals, the inner ends of the linear guide holes 25 are communicated with the inner parts of the self-wetting mechanism 26, when the bone trabecular metal total ankle joint prosthesis works, the talus connecting frame 1 is responsible for being connected with a talus, the joint device has supporting and connecting functions, the articulated ball 23 in the articulated groove 22 in the fixed seat 21 of the joint device 2 can flexibly move and is connected with the top of the talus connecting frame 1, the joint device can rotate at multiple angles in the articulated groove 22 according to the movement requirement of a human body, various movements of an ankle joint are realized, the wear-resistant ceramic gasket 24 fixed in the articulated groove 22 is tightly attached to the outer surface of the articulated ball 23, when the joint moves, the friction loss between the articulated ball 23 and the articulated groove 22 is effectively reduced, the durability of a prosthesis is improved, the self-lubricating mechanism 26 arranged on the outer surface of the articulated ball 23 at equal intervals is communicated with the inside of the articulated ball 23 by virtue of the linear guide hole 25, the self-lubricating mechanism 26 is activated in the process of the joint movement to convey lubricating substances into the linear guide hole 25, and the lubricating substance is uniformly guided to the contact part of the hinging ball 23 and the wear-resistant ceramic gasket 24 through the linear guide hole 25, so that continuous and uniform lubrication is realized, the stable and smooth operation of the joint device 2 is ensured, and the tibia connecting part 3 can be stably matched with the tibia along with the movement of the joint device 2, so that the function of the whole ankle joint prosthesis is completed.
Referring to fig. 1-6, the upper end of the outer surface of the hinge ball 23 is rotatably connected with a lubrication ball 27 at equal intervals, the outer side of the lubrication ball 27 is in fit connection with the inner wall of the wear-resistant ceramic gasket 24, the wear-resistant ceramic gasket 24 is made of wear-resistant zirconia ceramic material, when the bone trabecular metal total ankle joint prosthesis operates, the talus connecting frame 1 is connected with the talus to provide support for the whole device, in the joint device 2, the hinge ball 23 in the hinge groove 22 in the fixing seat 21 can flexibly rotate to drive the whole joint to simulate the movement of the human ankle joint, the outer side of the lubrication ball 27 is in fit with the inner wall of the wear-resistant ceramic gasket 24 made of wear-resistant zirconia ceramic material, when the joint moves, the hinge ball 23 rotates, the lubrication ball 27 rolls along with the joint ball, on one hand, the direct friction between the hinge ball 23 and the wear-resistant ceramic gasket 24 can be reduced, and the primary lubrication and buffer function can be achieved, on the other hand, the self-lubricating mechanism 26 is matched to provide a higher-efficient lubrication aid, the wear-resistant zirconia ceramic gasket 24 has good wear-resistant performance, the wear-resistant ceramic gasket 24 has good wear resistance performance, and the wear resistance performance of the joint 23 can well and the service life of the joint is well and the joint is well-resistant to the long, and the service life of the joint is ensured, and the service life is stable, and the service life of the joint is prolonged, and the life of the joint is stable.
Referring to fig. 1-7 and 9, the self-wetting mechanism 26 includes an elastic balloon 261, the elastic balloon 261 is fixed on the lower end of the outer surface of the hinged ball 23 in a circular arrangement at equal intervals, the outer bottom and the inner bottom of the elastic balloon 261 are both fixedly connected with a one-way valve 262, the output end of the one-way valve 262 located at the outer side is communicated with the inner side of the elastic balloon 261, the output end of the one-way valve 262 located at the inner end is communicated with the input end of the linear guide hole 25, the elastic balloon 261 is made of polycarbonate polyurethane, the elastic balloon 261 made of polycarbonate polyurethane is fixed at the lower end of the outer surface of the hinged ball 23 in a circular arrangement at equal intervals, when the hinged ball 23 is driven to rotate by the joint movement, the fixed seat 21 periodically extrudes the elastic balloon 261, and when the elastic balloon 261 is pressed, the inner air is contracted through the inner one-way valve 262, the air is prevented from flowing outwards due to the one-way valve 262 located at the outer side, when the hinged ball 23 rotates to release the elastic balloon 261 rapidly, the elastic balloon 261 is reset to generate negative pressure, and the elastic balloon 262 is smoothly pushed to the inner side through the linear guide hole 25, and the elastic balloon is stably runs to the inner side through the high-pressure, and the elastic guide hole is continuously, and the elastic fluid is smoothly conveyed to the inner side of the elastic balloon is stably, and the elastic balloon is stably runs to the inner side of the valve is pressed, and the elastic balloon is stably, and the elastic body is pressed.
Referring to fig. 1-4 and 7-10, the tibia connecting portion 3 includes a connecting main tube 31, a tibia connecting frame 32 is fixedly mounted at the top of the connecting main tube 31, the connecting main tube 31 is fixedly connected to the top of the fixing seat 21, outer macropores 33 are formed at equal intervals on the outer surface of the connecting main tube 31, inner micropores 34 are formed in the inner portion of the connecting main tube 31 and the inner walls of the outer macropores 33 are arranged at equal intervals in a ring shape, the aperture of the outer macropores 33 is larger than that of the inner micropores 34, the aperture of the outer macropores 33 is 500-800 μm, the aperture of the inner micropores 34 is 100-200 μm, microspheres 35 are arranged in the inner micropores 34, bone morphogenic proteins and vascular endothelial growth factors are loaded in the microspheres 35, mounting frames 4 are fixedly connected to two sides of the bottom of the talus connecting frame 1, the lower end of the mounting frame 4 is provided with a mounting hole, the outer surfaces of the connecting main pipe 31, the tibia connecting frame 32, the hinge ball 23 and the talus connecting frame 1 are respectively provided with an antibacterial composite coating 5, the antibacterial composite coating 5 is a coating doped with silver nano particles (0.5-1 wt%) or quaternary ammonium salt compounds in the HA coating, the tibia connecting frame 32 fixed at the top of the connecting main pipe 31 is used for being firmly connected with tibia in the tibia connecting part 3, the connecting main pipe 31 is fixed at the top of the fixing seat 21, the stability of the joint device 2 and tibia connection is ensured, the outer surface of the connecting main pipe 31 is provided with an outer layer macroporous 33 with the aperture of 500-800 mu m, a spacious channel is provided for bone tissue ingrowth, the preliminary combination of the prosthesis and surrounding bones is promoted, the inner layer micropores 34 with the inner aperture of 100-200 mu m greatly increases the surface area, the mounting frames 4 with the mounting holes are arranged on two sides of the bottom of the talus connecting frame 1 to be conveniently connected with talus, so that the overall continuity of the ankle joint prosthesis is ensured, and the antibacterial composite coating 5 on the outer surfaces of the connecting main pipe 31, the tibia connecting frame 32, the hinge ball 23 and the talus connecting frame 1 can be used for effectively inhibiting bacterial growth, reducing postoperative infection risk, ensuring long-term stable operation of the prosthesis and providing a guarantee for health of patients no matter whether the HA coating is doped with 0.5-1wt% of silver nano particles or the quaternary ammonium salt compound coating.
The technical scheme provided by the application has the following specific working processes:
The ankle joint frame body is provided with the innovative joint device 2, and shows excellent performance and adaptability in practical application, the core of the joint device 2 is that the hinge ball 23 is in subtle fit with the fixed seat 21, the hinge ball 23 can flexibly rotate in the hinge groove 22 on the fixed seat 21, and the design enables the ankle joint frame body to adaptively adjust the rotation angle according to the movement requirement of a human body when adapting to the ankle joint of the human body, effectively simulate the movement range of the natural ankle joint, and promote the action comfort level and flexibility of a patient.
In the running process of the joint, the wear-resistant ceramic gasket 24 is tightly attached to the hinged ball 23, so that friction loss generated when the hinged ball 23 rotates is greatly reduced by virtue of excellent wear resistance, the service life of the ankle joint frame body is remarkably prolonged, in addition, the lubricating balls 27 which are arranged at equal intervals on the upper end of the outer surface of the hinged ball 23 play an excellent self-lubricating function when the hinged ball 23 rotates, the fixed seat 21 can apply periodic extrusion force to the elastic bag body 261, and in the extrusion stage, the elastic bag body 261 is compressed under the action of external force, and internal air is rapidly discharged; when the hinged ball 23 rotates to the other side, the pressure applied to the elastic bag body 261 is relieved, the elastic bag body 261 expands and resets, in the process, surrounding tissue lubricating liquid is sucked into the elastic bag body 261 through the outer one-way valve 262, due to the unidirectional flow characteristic of the one-way valve 262, the tissue lubricating liquid only can enter the elastic bag body 261 in one direction, when the hinged ball 23 rotates and extrudes the elastic bag body 261 again, the outer one-way valve 262 prevents the liquid from reversely flowing out, the inner one-way valve 262 allows the liquid to flow from inside to outside, the tissue lubricating liquid in the elastic bag body 261 is conveyed to the top of the hinged ball 23 through the inner one-way valve 262 under the action of extrusion force through linear guide holes, the linear guide holes 25 are distributed at equal intervals along the rings Rao Jiao, the tissue lubricating liquid can be uniformly infiltrated into the surfaces of the hinged ball 23 and the abrasion-resistant ceramic gaskets 24, the lubricating performance in the joint rotating process is improved in all directions, abrasion is effectively reduced, and smooth operation of the joint is ensured.
In the ankle joint prosthesis application, the tibia connecting part 3 plays a key role in promoting bone growth and rapidly realizing osseointegration, the tibia connecting frame 32 fixedly arranged at the top of the connecting main pipe 31 is made of a material with high strength and good biocompatibility, stable and reliable connection with tibia is ensured, the connecting main pipe 31 is fixed at the top of the fixing seat 21, the stability of the whole structure is further enhanced, stress generated during joint movement is effectively dispersed, the mechanical property of the prosthesis in a human body is improved, the outer macropores 33 formed at equal intervals on the outer surface of the annular connecting main pipe 31 are accurately controlled to be 500-800 mu m, an ideal channel is provided for bone tissue growth, the tight combination of the prosthesis and surrounding bones is greatly promoted, the anchoring effect of the prosthesis at a tibia part is remarkably enhanced, the inner micropores 34 formed in the inner part of the connecting main pipe 31 and in an annular arrangement mode are equidistant on the inner wall of the annular outer macropores 33, the micropores are greatly increased in surface area, the surface area can be effectively adsorbed by growth factors, the stress generated during the joint movement is effectively dispersed, the mechanical property of the prosthesis is improved, the bone-carrying protein and the vascular protein arranged in the micropores are formed in the micropores, the vascular protein and the vascular protein are formed at the inner surface of the human bone or the endothelial protein and the human bone growth factor is remarkably and the human endothelial protein is remarkably recombined to be released at the human bone growth 2-endothelial growth stage, and the human bone growth factor is remarkably and the human bone growth-promoting growth stage is greatly improved; the mounting frame 4 fixedly connected with the two sides of the bottom of the talus connecting frame 1 has scientific and reasonable design, the mounting hole arranged at the lower end of the mounting frame 4 provides a convenient and stable mode for the connection with the talus, the continuity and the integrity of the whole ankle joint prosthesis in structure and function are ensured, the outer surfaces of the connecting main pipe 31, the tibia connecting frame 32, the hinging balls 23 and the talus connecting frame 1 are coated with an antibacterial composite coating 5, the HA coating is used as a coating material, 0.5-1wt% of silver nano particles or quaternary ammonium salt compounds are doped in the coating material, and the antibacterial components have strong antibacterial performance, can effectively inhibit the breeding and propagation of bacteria, obviously reduce the postoperative infection risk, and provide firm and reliable guarantee for long-term stable operation after the prosthesis is implanted and the physical health of patients.
The ankle joint prosthesis adopts a precise spherical matching structure, a hinge ball 23 rotating at a degree of freedom of +/-30 degrees is cooperated with a fixed seat 21 to construct an intelligent lubrication system, a medical grade silicon rubber elastic bag body 261 is combined, the system drives the elastic bag body 261 to realize piston type liquid circulation through a cam effect, when the joint motion generates periodic displacement, the elastic bag body 261 absorbs joint sliding liquid at a rate of 2-5 mu L/time through an outer one-way valve 262 (aperture 0.1-0.3 mm), when the hinge ball 23 rotates to a limiting position, internal pressure of 20-50kPa is generated, the sliding liquid is forced to enter a high-density micropore network (50-80 holes/cm <2 >) through an inner one-way valve 262 (aperture 0.05-0.1 mm), a linear guide hole adopts a bionic sliding film villus structure, and a uniform lubricating film (thickness 5-10 mu m) is formed at the interface of a ceramic gasket and the hinge ball 23 through surface tension gradient design, so that the friction coefficient is reduced to 0.015-0.02, and the smoothness of the joint motion is remarkably improved.
The tibia connecting part 3 adopts a three-dimensional collaborative design, promotes osseointegration through a gradient pore structure, a growth factor slow-release system and a dynamic stress stimulation triple mechanism, forms a graded bone ingrowth channel by an outer layer 500-800 mu m titanium alloy grid and an inner layer 100-200 mu m honeycomb micropore, realizes biphasic release of BMP-2 (30% +60 days sustained release > 80%) by matching with PLGA microspheres 35 prepared by microfluidics, and generates 10-50 mu A pulse current when an integrated 0.2mm thick piezoelectric ceramic chip bears a load of >150N, and activates osteoblast differentiation and angiogenesis by regulating and controlling a current density of 0.1-1.0mA/cm < 2>, so as to form a synergistic effect of bone-blood vessel synchronous growth.
The surface protection adopts a multi-layer composite architecture, long-acting antibacterial is realized through the synergistic effect of the nanostructure layer, the slow-release antibacterial layer and the biocompatible layer, the TiO2 nanotube array (with the pipe diameter of 50-100 nm) prepared by micro-arc oxidation is loaded with 0.8-1.2mg/cm < 2 > of silver ions to form a physical barrier, the minimum inhibitory concentration of chitosan/quaternary ammonium salt coating (with the thickness of 2-5 μm) on staphylococcus aureus is less than 5 mu g/mL, and the PEG grafting modification reduces the protein adsorption amount by more than 80%, so that bacterial adhesion and biofilm formation are effectively inhibited, and the postoperative infection risk is reduced.
The device adopts a manufacturing technology of multidisciplinary fusion, comprises five-axis CNC processing of cobalt-chromium-molybdenum alloy hinge balls 23 (Ra is less than or equal to 0.4 mu m), SLM preparation of a titanium alloy porous support (porosity control + -2%), an intelligent upgrading scheme comprises integration of a miniature pressure sensor (precision + -0.5% FS) to realize real-time load monitoring, surface grafting of PEGDA hydrogel (swelling rate 300%) and introduction of a bionic micro-fluff structure (50-100 mu m high), and the lubricating efficiency is improved while the biocompatibility is maintained.
The invention is intended to cover any alternatives, modifications, equivalents, and variations that fall within the spirit and scope of the invention. In the following description of preferred embodiments of the invention, specific details are set forth in order to provide a thorough understanding of the invention, and the invention will be fully understood to those skilled in the art without such details. In other instances, well-known methods, procedures, flows, components, circuits, and the like have not been described in detail so as not to unnecessarily obscure aspects of the present invention.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.