P1/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR AN INNOVATION PATENT ORIGINAL Name of Applicant: AUSTRALIAN PREBUILD GROUP PTY LTD Actual Inventors: Corie GALE Daniel GAYNOR Address for Service: Houlihan 2 , Level 1, 70 Doncaster Road, Balwyn North, Victoria 3104, Australia Invention Title: BUILDING SYSTEM AND METHOD The following statement is a full description of this invention, including the best method of performing it known to the Applicant: 1 BUILDING SYSTEM AND METHOD Field of the Invention [0001] The present invention relates to prefabricated building components and/or units and methods of use thereof. In particular, the invention relates to prefabricated wet area units, such as pre-fabricated bathroom units, and to a method of installation of same into a building. Background to the Invention [0002] Construction of apartments and other multi-story housing units is commonplace and generally follows standard, regulated procedures and protocols. These types of building structures can take weeks or months to construct, requiring many different types of materials and construction phases to complete. [0003] Recent developments in materials and structural engineering have allowed builders to construct multi-story buildings using prefabricated, transportable components and/or units. These prefabricated units are often assembled in substantial part before delivery to the specific location to reduce the overall time required to complete a building project. Bathrooms are particularly suited to being constructed offsite since they are time consuming to build and are quite self-contained by virtue of being substantially isolated from the remainder of the dwelling due to the need for water-proofing. [0004] Installation of the prefabricated units, such as a pre-fabricated bathroom unit, conventionally involves lifting the unit into place, adjusting the floor and ceiling heights of the unit, followed by connecting the internal piping and wiring within the pre fabricated unit to various external services, including plumbing, electricity and sewerage. Pre-fabricated bathroom units in multi-story buildings are usually located above one another so that all necessary services may be conveniently located in certain parts of the multi-story building. [0005] For obvious reasons, any work on one level of a multi-story building cannot be initiated until the structural build of the supporting level below it has been completed. Furthermore, specialized tradesmen, such as plumbers and electricians, typically require access to a newly located pre-fabricated bathroom on the building site in order to carry 2 out the connection of the internal piping and wiring within the pre-fabricated bathroom unit to the various external services. Such work tends to delay the structural preparation of the next level of the multi-story building, increasing costs. Costs are further increased by the need for specialized tradesmen, such as plumbers and electricians, to attend the building site, and effect connections of services for each unit after installation. [0006] The present invention relates to improved pre-fabricated building units, methods of construction, and methods of installing same, that provide significant advantages over previously known units and installation methods thereof. Summary of the Invention [0007] Broadly, the present invention provides an improved pre-fabricated building unit and method of installing same within a building, the method involving the steps of lifting and lowering a unit to be installed while simultaneously supporting formwork for use in pouring concrete for the support of another unit. [0008] The inventors have surprisingly found that the sequential lifting and lowering of a pre-fabricated building unit on a first loading-bearing surface on a first level during installation allows the simultaneous preparation of a second-loading bearing surface on a level above. [0009] Accordingly, the present invention provides an improved pre-fabricated building unit comprising: a) a floor comprising unit lifting and lowering means; b) a load-bearing planar roof substantially parallel to the floor, the roof comprising formwork; c) a plurality of load-bearing walls extending between the floor and the roof, and secured thereto; and d) elongate removable spacers which are transversely disposed within the plurality of load-bearing walls and substantially parallel with the roof. [0010] The unit lifting and lowering means may be synonymous. The unit lifting and lowering means may, in use, abut a lower load-bearing surface. In a preferred embodiment, the unit lifting and lowering means both comprise a plurality of load 3 bearing bolts disposed around the perimeter of the floor and projecting outwardly there through, the heads of the bolts internally located proximal to the floor of the unit. The bolts are operatively pivotable such that tightening of the bolts causes the end of the bolts to bear against the lower load-bearing surface beneath the unit, thereby lifting the unit. Similarly, loosening of the bolts causes the end of the bolts to bear against the load bearing surface, thereby lowering the unit. [0011] The improved pre-fabricated building unit may comprise: a) a lower section comprising: i) a floor comprising unit lifting and lowering means; ii) a first plurality of load-bearing walls extending upwardly from the floor and secured thereto; and b) an upper section comprising: i) a load-bearing planar roof, the roof comprising formwork; ii) a second plurality of load-bearing walls extending downwardly from the roof and secured thereto; and c) fastening means for contiguously securing the first and second plurality of load-bearing walls relative to one another such that the roof is disposed substantially parallel to the floor; and d) elongate removable spacers which are transversely disposed between the first plurality of load-bearing walls and the second plurality of load bearing walls. [0012] The invention extends to a lower section part for use in assembling an improved pre-fabricated building unit of the invention, the lower section comprising: a) a floor comprising unit lifting and lowering means; and b) a first plurality of load-bearing walls extending upwardly from the floor and secured thereto. [0013] The invention also extends to an upper section part for use in assembling an improved pre-fabricated building unit of the invention, the upper section comprising: a) a load-bearing planar roof, the roof comprising formwork; and b) a second plurality of load-bearing walls extending downwardly from the roof and secured thereto. 4 [0014] The load bearing walls may house a lifting rod, the lifting rod secured to the floor at its lower end and comprising a loop at its upper end which extends above the roof of the unit. [0015] The elongate removable spacers may be between 10mm and 300mm in width. Preferably, the elongate removable spacers are between 20mm and 100mm in width. The spacers are preferably located in load bearing points within the wall, proximal to the fastening means. [0016] The improved pre-fabricated building unit may further comprise pre-installed service piping and/or wiring connections for connection to another improved pre fabricated building unit of the invention. The unit may further comprise pre-installed acoustic material. [0017] The floor may comprise a steel plate having a thickness of about 5mm to 50mm. Preferably the steel plate is about 10mm thick. The floor may further comprise a tubular perimeter, such as a perimeter comprising Short Hollow Steel sections ("SHS"). [0018] The walls may be secured to the floor and/or roof by way of a nutted bolt. The nutted bolt may be fastened to the SHS. [0019] The walls may be permanent or temporary. [0020] The invention also provides a method of constructing an improved pre fabricated building unit according to the invention, the method comprising the steps of: a) constructing a lower section according to the invention; b) constructing an upper section according to the invention; c) placing the upper section on the lower section; and d) fastening the fastening means, thereby securing the upper section to the lower section. [0021] The step of constructing the lower section may be carried out on a delivery platform. 5 [0022] The invention also provides a method of installing an improved pre-fabricated building unit of the invention, the method comprising the steps of: a) locating a pre-fabricated building unit of the invention onto a first load bearing surface; b) operating the unit lifting means and lifting the unit; c) pouring concrete onto the roof of the unit, within the formwork; d) operating the unit lowering means and lowering the unit; e) striking the concrete; f) operating the unit lifting means and lifting the unit; g) setting the concrete to form a second load-bearing surface; h) operating the unit lowering means and lowering the unit; and i) removing the spacers from the walls of the unit. [0023] The invention extends to a method of preparing a second load-bearing surface for an improved pre-fabricated building unit of the invention, the method comprising the steps of: a) locating a pre-fabricated building unit of the invention onto a first load bearing surface; b) operating the unit lifting means and lifting the unit; c) pouring concrete onto the roof of the unit, within the formwork; d) operating the unit lowering means and lowering the unit; e) striking the concrete; f) operating the unit lifting means and lifting the unit; g) setting the concrete to form a second load-bearing surface; h) operating the unit lowering means and lowering the unit; and i) removing the spacers from the walls of the unit. [0024] In a preferred embodiment, steps a) to i) are repeated to prepare a third load bearing surface. [0025] In a preferred embodiment, in which the unit lifting and lowering means comprise a plurality of load-bearing bolts disposed around the perimeter of the floor and projecting outwardly there through, the steps of operating the unit lifting and lifting means may comprise screwing and unscrewing the bolts respectively. 6 [0026] The first-loading bearing surface may comprise a set concrete surface prepared according to the method of the invention. [0027] It will be appreciated that the step of removing the spacers from the walls of the unit results in the unit no longer supporting the concrete which has set into a second loading surface. [0028] It will be appreciated that the steps of pouring the concrete, striking the concrete, and setting the concrete may be carried out according to standard procedures known in the art and using standard equipment suitable for the purpose. Brief Description of the Figures [0029] Figure 1 shows a line drawing of the lower section of unit of the invention in elevation view (A) and of the base plate with SHS attached in plan view (B). Expanded cross-sectional side views of the bolts comprising the unit lifting and lowering means in the corners of the base plate are shown in (C) and along the perimeter of the base plate in (D). [0030] Figure 2 shows a line drawing in elevation view of the lower section (A) and the upper section (B) of the unit of the invention which, when assembled together, form the prefabricated unit (C) of the invention. [0031] Figure 3 shows CAD drawings in perspective view (A), side view (B), and end view (C) of an assembled pre-fabricated unit of the invention according to an embodiment which comprises permanent walls. [0032] Figure 4 shows CAD drawings of the bolts in the corner of the base plate of the unit of the invention of Figure 3 in expanded side view (A) and in expanded perspective view (B), and of the bolts along the perimeter of the base plate in expanded side view (A) and in expanded transparent, perspective view (D). [0033] Figure 5 shows CAD drawings in perspective view (A), side view (B), and end view (C) of an assembled pre-fabricated unit of the invention according to an embodiment which comprises temporary travel walls. 7 [0034] Figure 6 shows CAD drawings of the bolts in the corner of the base plate of the unit of the invention of Figure 5 in expanded perspective view (A), in expanded transparent, perspective view (B) and in side view (C), and of the bolts along the perimeter of the base plate in expanded perspective view (A), in expanded transparent, perspective view (B) and in side view (C). An expanded view of the ceiling subframe is shown in perspective view (G) and in transparent, perspective view (H). An expanded view of the roof showing the lifting rod is shown in perspective view (I). [0035] Figure 7 shows a line drawing of the assembled unit according to an embodiment of the invention with comprises travel walls, in elevation view (A) and of the base plate in plan view (B). Expanded side views of the bolts at the corner of the base plate are shown in in cross-sectional side view (C) and in top view (D), and of the bolts along the perimeter of the base plate in cross-sectional side view (E) and in top view (F). [0036] Figure 8 shows a line drawing of an installed unit according to an embodiment of the invention with plastering applied, in elevation view (A) and in plan view (B). [0037] Figure 9 shows a line drawing of a manufacture and delivery platform on which the unit is constructed and assembled, in top view (A) and in front elevation view (B) and in side elevation view (C). Detailed Description of the Invention [0038] The following detailed description of the invention refers to all the Figures wherein like reference numerals designate like or corresponding parts throughout the several views. The Figures show exemplary embodiments of the present invention, and it is to be understood that these embodiments are not intended to limit the scope of the present invention. The skilled addressee will readily recognise alternative embodiments that may be used to put the present invention into practice, such embodiments are equally understood to be encompassed by the present invention. Accordingly, the following description refers to specific embodiments of the present invention and is in no way intended to limit the scope of the present invention to those specific embodiments. [0039] The present invention relates to the provision of improved prefabricated building units for installation into housing units, preferably multistorey buildings. The invention 8 also relates to a method for installing the improved prefabricated building units of the invention, in a stacked fashion, including simultaneous preparation of supporting formwork on the roof of each lower unit in order to support the later installation of a unit above. [0040] As shown in the Figures, each prefabricated building unit comprises a floor, a roof, and a plurality of load-bearing walls which are constructed in sections and assembled into the completed prefabricated building unit, preferably directly on a delivery platform. The prefabricated building unit is then installed onto a first load bearing surface in a building, typically a multi-story building, and a second-load-bearing surface in the form of a concrete slab is simultaneously prepared above the unit during installation. Prefabrication of building units [0041] The building units (10) are first prefabricated before installation, usually at a factory which is remote from the building site. As shown in Figure 1, the floor (12) of each unit (10) is typically made from a 10 mm steel plate (14) which is cut to size. Penetration holes (16) for the connection of services (not shown), including piping and wiring for plumbing, sewerage, and electricity services, are typically laser cut into the base plate (14) at pre-determined locations. The location of each of these holes (16) is established before cutting, using typical software known in the art, such as AutoCAD software. [0042] In addition, a 35mm hole (16.1) is cut into each corner of the base plate (14), as well as around the perimeter (16.2) of the base plate (14), and a M30 nut (18) is welded to the base plate (14) over each of these holes (16). 89 mm x 89 mm x 3.5 mm Square Hollow Steel sections ("SHS") (20) are welded to the upper surface of the base plate (14), around the perimeter thereof, to provide seating for the walls (22). Sections are cut out of the SHS so that it sits correctly over the M30 nuts (18), which are welded over each of the holes (16) in the base plate (14). The SHS (20) is then welded to the base plate (14), substantially in all areas, except along the edges where the doorway is to be located (24). A square 80 mm x 80 mm x 10 mm steel plate (26), with a corresponding hole (not 9 shown), is welded to the underside of the upper surface of the SHS (20), under each of the holes (16), as shown in Figure 1C, and a M16 nut (28) welded to the plate (26). [0043] The floor (12) of each unit (10) comprises unit lifting and load-bearing means, typically in the form of a plurality of load-bearing bolts (30). A M30 bolt (30), 150 mm in length, is inserted through each nut (18) and into each hole (16.2) around the perimeter of the base plate (14), and in the corners (16.1) thereof, and protruded through the hole (16) such that 20 mm of the bolt (30) extends below the lower surface of the base plate (14). In this way, the plurality of bolts (30) are disposed around the perimeter of the floor (12) and project outwardly therefrom, and the heads of the plurality of bolts (30) are internally located within the unit (10), proximal to the floor (12). [0044] As shown in Figures 2 and 3, the unit (10) is preferably assembled in two sections: a lower section (10.1) (as shown in Figure 2A) and an upper section (10.2) (as shown in Figure 2B). Once the floor (12) has been completed, a framework for the walls (22) is prepared. A lightweight steel frame (22.1) is constructed for the lower section (10.1), from a plurality of steel posts, typically 2301 millimetre in height. The steel framework (22.1) is manufactured using 1mm steel coils, which have been processed through a framing machine and assembled by hand. Each steel post has a 30 mm wide channel (32) longitudinally located within the steel post, at each corner of the unit (10), to permit the insertion of a 16 mm lifting rod (34). Once erected and secured, the framework (22.1) for the lower section (10.1) is bolted to the top of the SHS steel (20), through the 80 mm x 80 mm x 10 mm steel plates (26) and the M16 nut (28), as shown in Figure 1C. A spacer in the form of a 20 to 30 mm deflection packer (36) is placed at the top of each of the steel posts (22.1) of the lower section (10.1). [0045] The steel framework (22.2) for the ceiling subframe and upper section (10.2) is constructed in a similar manner from a plurality of steel posts, the spacing between the steel posts corresponding to the spacing between the steel posts of the lower section (10.1). The ceiling subframe may be adjusted internally, to a desired ceiling height. [0046] To prepare the upper section (10.2), form ply (38) is secured to the ceiling subframe to form a roof (40), the form ply (38) suitable for use as concrete formwork. The form ply (38) may comprise compress sheeting, where required, for fire rating purposes. The upper section (10.2) is conveniently constructed at ground level, or at a 1 10 metre working height, such as on a table (39), to facilitate and accelerate production time and the installation of plumbing, mechanical, electrical services, as well as for work safety purposes. The form ply (38) is then waterproofed, externally and/or internally, according to standard procedures known to those skilled in the art. [0047] The upper section (10.2) is placed on top of the lower section (10.1), with the framework (22.2) of the upper section (10.2) corresponding with the framework (22.1) of the lower section (10.1), as shown in Figure 2C. Additional holes (42) are cut into the steel posts of the lower section for plumbing and electricity services (not shown). A 16 mm lifting rod (34) is inserted into the longitudinal channel (32) of each corner steel posts, and secured to the top of the SHS steel (20) through a 16mm hole in the 80 mm x 80 mm x 10 mm steel plates (26) and the M16 nut (28), as shown in Figure 1C. [0048] It may be desirable for the prefabricated building units (10) of the invention to comprise prefabricated walls, such as for use in instances where a prefabricated bathroom is intended to have walls on all sides thereof. According to some embodiments of the invention, and as shown in Figures 3 and 4, all of the framework (22.1, 22.2) of the upper (10.2) and lower sections (10.1) of the unit (10) may be prepared and assembled as described above. Furthermore, the ceiling height of the prefabricated unit (10) may be predetermined as required. [0049] It may be also desirable for the finished unit (10) to be open plan with a neighbouring room in the building, such as a bedroom. According to other embodiments of the invention, and as shown in Figures 5, 6 and 7, some of the framework (22.1, 22.2) of the upper (10.2) and lower (10.1) sections maybe constructed to be removable. Accordingly, temporary travel walls (44) may be prepared and fitted to the unit (10) before transport, to ensure that the ceiling and base plate (14) of the units (10) do not deflect during transportation. These travel walls (44) may be removed upon completion of installation, in instances where, for example, a bathroom is intended to be open plan with a neighbouring bedroom. [0050] In such embodiments, which comprise temporary travel walls (44), the lower (10.1) and upper (10.2) sections of the unit (10) are prepared in a similar manner to that described above. However, a continuous length of 89mm x 89mm x 3.5mm SHS (20) is only welded to those sides of the unit (10) which are to have pre-installed permanent 11 walls (22) that are retained on completion of the room. Along the perimeter of the base plate (14) to which temporary walls (44) are to be attached, short sections of 89mm x 89mm x 3.5mm SHS (46) are welded. Temporary travel walls (44) are typically constructed from 75mm x 75mm x 3.0mm SHS struts (44.1), the ends of which are transversely welded to the short sections of 89mm x 89mm x 3.5mm SHS (46) spaced around the perimeter (46.2) of the base plate (14) the lower section (10.1), as shown in Figures 5 and 6. M16 bolts (48) are inserted into 16 mm holes cut into the short sections of SHS (46), extending 20mm below the lower surface of the base plate (14). The M16 bolts (48) are typically located on either side of the strut (44.1), at a distance of about 200 mm, as shown in Figure 7 C. In corner posts which are to be temporary, a corner section of SHS (46.1) is welded to the base plate (14), and a M16 bolt (48) is inserted into a hole, through the base plate (14). A 80 mm x 80 mm x 10 mm steel plate (26) having a 16 mm hole is welded to the upper surface of the SHS (46), and a M16 nut (28) welded in place, in a similar manner to that described above. The framework (44.2) of the upper section (10.2) are also constructed in a similar manner, and the upper (10.2) and lower (10.1) sections assembled. After assembly, a M16 threaded rod (34) is inserted in the corner posts and bolted to the SHS (46), as shown in Figure 7 D, to provide a lifting rod. [0051] Once the completed prefabricated building unit (10) is assembled, and ready for transportation to the building site, the unit (10) is placed on a platform (50) having a pair of 250 UB external beams (52), a centre beam (54) and 250 UB forklift pockets (not shown), according to Figure 7. The unit (10) is preferably conveniently constructed and assembled directly on the platform (50), as set out above, to expedite pre-fabrication, transport and delivery from the unit factory to the building site. Installation [0052] After delivery of the pre-fabricated building unit (10), typically on a platform (50), the unit (10) is lifted into place onto a desired level of, for example, a multi-storey building using a crane, and hoisted into place by way of the lifting rod (34). The unit (10) is positioned and located into place onto a first load-bearing surface (not shown), usually a fully tensioned concrete slab. 12 [0053] A user will then tighten the heads of the M30 bolts (30) and the M16 bolts (48) disposed around the perimeter of the floor (12), and proximal thereto, causing the ends of the bolts (30, 48) to bear against the first load-bearing surface beneath the unit (10), thereby lifting the unit (10). The lifting of the unit (10) causes the waterproofed form ply (38) on the roof of the unit (10) to align with the floor (12) of the level above. Concrete is then poured onto the roof of the unit (10), and the weight of the concrete is supported by the unit (10). [0054] The user then loosens the heads of the M30 bolts (30) and the M16 bolts (48), causing the ends of the bolts (30, 48) to bear against the first load-bearing surface beneath the unit (10), thereby lowering the unit (10). Striking of the concrete is carried out. The unit (10) is again lifted in a similar manner, and the concrete slab allowed to set and form a second load-bearing surface (not shown). Once the concrete slab is fully tensioned, the unit (10) is lowered by loosening the bolts (30, 48) as before, and the deflection spaces (36) are removed from the walls (22, 44) of the unit (10), so that the roof of the unit (10) is spaced from the concrete slab above it by about 20mm to 30mm. After the spacers (36) have been removed, the unit (10) no longer supports the concrete slab. The formwork (38) on the unit (10) thereafter acts as the roof or ceiling of the completed room. If a ceiling has been included in the ceiling subframe of the upper section, the roof is then located between the ceiling of the unit (10) and the concrete slab. [0055] If the unit (10) comprises temporary travel walls (44), these walls may be removed by angle-grinding the welded 89mm x 89mm x 3.5mm SHS (46) from the base plate (14) of the unit (10). The lifting rod (34) may also be conveniently and easily removed from the corner struts of the unit (10) after installation, and reused. [0056] Where a second prefabricated building unit (10) is to be installed on the second load-bearing surface, holes may be cut through the concrete slab of the second load bearing surface and the roof, to correspond with connection points in the base plate (14) of the second prefabricated building unit (10), and in the upper section of the first installed unit (10). In this way, a second unit (10) may be rapidly installed on the second load-bearing surface, and services connected to pre-installed piping and wiring present in the upper section of the unit (10) installed in the level below. 13 [0057] Once installed, the walls (22) of the unit (10) may be plastered according to standard procedures known to those skilled in the art, such as for example, by using plasterboard. As shown in Figure 8, an advantage of the unit (10) of the invention is that it may be constructed to comply with fire rating requirements. For example, the walls (22) that are disposed between the unit (10) and common areas may have 16mm fire check plaster applied to them (shown in dotted lines in Figure 8). The walls (22) of the unit (10) adjacent to adjoining apartment walls may have two 13mm fire check plaster applied to them. [0058] Once completed, the finished floor height of the unit (10) is at 22mm, so that other floor coverings can be merged to the same height. [0059] Conventional prefabricated units make use of a thick base plate (14) that can be as thick as 100mm, such that a rebate in the concrete slab acting as a load-bearing surface is needed to achieve the required 22 millimetres finished floor height. If the concrete slab is not rebated in this manner, the bathroom can have an undesirable threshold step of up to 100mm. Such rebating of the concrete is time-consuming, and causes delay which increases costs. [0060] An advantage of the present invention is that, the installation of the prefabricated building units described limits or minimises the requirement for the concrete slab to be rebated to achieve a specific finished floor height, for example, a 22mm finished floor height. Furthermore, the units are designed to have a rigid, durable base, to substantially prevent deflection during transportation of the unit, or at least to minimise deflection to at least 1 to 3 mm through the floor. In this way, a finished floor of a desired height may be conveniently and quickly achieved using the prefabricated building unit of the invention and method of installation thereof. [0061] Furthermore, the separate construction of the lower section and upper section of the prefabricated building units, according to the method of the invention facilitates quick and convenient construction, as well as increasing work safety during construction. Since the upper section of the prefabricated building units is constructed at ground level, or at a working height of im, there is no need for a user to work at an elevated height. This allows for all piping and wiring for services such as plumbing, sewage and electricity to be conveniently installed in the upper section of the prefabricated building units of the 14 invention. Since such pre-installation requires the services of specialised tradesmen, such as plumbers and electricians, this work can be carried out on the upper section of the unit, separately from the lower section, and off-site from the building site in which the unit is to be installed, thereby expediting installation of specialised services in the unit and reducing building costs. [0062] In addition, the use of waterproofed formwork on the roof of the prefabricated building unit permits the use of the roof as both formwork for the pouring concrete above the installed building unit, as well as for keeping the unit waterproofed against the weather whilst on site. [0063] The use of removable deflection spaces in the walls of the unit of the invention advantageously allows the disconnection of the installed unit from the set concrete above it, so that once the concrete slab is fully tensioned and can function as a load-bearing surface, the removal of the spaces allows the concrete slab to deflect without applying any pressure load to the unit. This is desirable to prevent any cracks or similar damage to the completed room after installation of the unit, increasing the longevity of the building and reducing maintenance costs. [0064] The present invention is not to be limited in scope by the specific embodiments and Figures described herein, which are intended as single illustrations of individual aspects of the invention, and functionally equivalent methods and components are within the scope of the invention. Indeed, various modifications of the invention, in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and accompanying Figures. Such modifications are intended to fall within the scope of the present invention. [0065] Where the terms "comprise", comprises", "comprising", "include", "includes", "included" or "including" are used in this specification, they are to be interpreted as specifying the presence of the stated features, integers, steps or components referred to, but not to preclude the presence or addition of one or more other feature, integer, step, component or group thereof. 15 [0066] Further, any prior art reference or statement provided in the specification is not to be taken as an admission that such art constitutes, or is to be understood as constituting, part of the common general knowledge. [0067] One of ordinary skill in the art will appreciate that materials and methods, other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by examples, preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. 16