INTRODUCTION

The present invention relates to an absorbent article for use in a wound product (e.g. a wound dressing) and a method of manufacturing such an absorbent article. In particular, but not exclusively, embodiments of the present invention relate to an absorbent article including a plurality of fibres and a foam, which can provide improved conformability, absorbency and strength compared to known wound products. BACKGROUND

Currently available wound dressing generally have one of three different types of structure. These include fibre based structures, foam based structures and laminate structures including foam and fibrous layers. Fibrous dressings are often used to provide absorbency and drape-ability but can sometimes shed fibres. Fibres that have been shed can become lodged in the wound bed and can cause damage to the wound bed on removal of the wound dressing from the wound. Fibrous dressings also are not usually suitable for cutting to size since exposed fibres along a cut line can more easily become loose and embedded within a wound.

Foam dressings are often desirable since they are gentle to the wound bed and can help to promote healing. However, in some foam dressings the absorbent capacity of the foam can be limited, particularly when the foam is under compression. Also, in some cases the strength of the foam may be limited.

SUMMARY

According to a first aspect of the present invention there is provided an absorbent article for a wound product, the absorbent article comprising:

a composite composition comprising a foam matrix and a plurality of fibres; wherein the plurality of fibres are at least partially encapsulated within the foam matrix.

Suitably, at least 80 % of the plurality of fibres are fully encapsulated within the foam matrix.

Suitably, at least a portion of the plurality of fibres extend into cells of the foam matrix. Suitably, wherein the plurality of fibres comprise fibre elements of between 0.8 dtex and 80 dtex. Preferably, the plurality of fibres comprise fibre elements of between 0.8 dtex and 15 dtex. The plurality of fibres may comprise fibre elements of less than 10 dtex. In other embodiments the plurality of fibres may comprise a first plurality of fibres of between 2 and 4 dtex and a second plurality of fibres between 8 and 12 dtex.

Suitably, the plurality of fibres comprise fibre elements of from about 4 mm to 100 mm in length. Suitably, the plurality of fibres comprise continuous filaments.

Suitably, the plurality of fibres form a sheet of fibrous material, and wherein the sheet of fibrous material is at least partially encapsulated within the foam matrix. Suitably, a first surface of the sheet of fibrous material is exposed and at least a second surface of the sheet of fibrous material is encapsulated within the foam matrix.

Suitably, the sheet of fibrous material comprises a woven fabric, a knitted fabric, a braided fabric, or a nonwoven fabric.

Suitably, the plurality of fibres comprise at least one of a viscose and a superabsorbent polymer fibre.

Suitably, the plurality of fibres comprise viscose fibres.

Suitably, the absorbent article comprises superabsorbent material.

According to a second aspect there is provided a wound product comprising the absorbent article of the first aspect. The wound product of the second aspect of the invention can be a wound dressing for use in a negative pressure wound therapy system.

Suitably, the absorbent article for use in the second aspect of the invention can comprise a moisture vapour permeable top film. Suitably, the absorbent article for use in the second aspect of the invention can comprise superabsorbent material. Suitably, the wound product further comprises a negative pressure interface for providing negative pressure to the absorbent article.

According to a further aspect of the present invention there is provided a negative pressure wound therapy system comprising:

an absorbent article for use as a wound dressing, the absorbent article comprising:

a composite composition comprising a foam matrix and a plurality of fibres; wherein the plurality of fibres are at least partially encapsulated within the foam matrix; and a vacuum source.

Suitably, the vacuum source is a vacuum pump.

Suitably, the negative pressure wound therapy system is canisterless. In such embodiments the negative pressure wound therapy system does not comprise a canister for collecting exudate from the wound. Rather, wound exudate may be substantially retained in the absorbent article.

Suitably, the negative pressure wound therapy system can comprise an absorbent article according to the first aspect of the invention or the second aspect of the invention.

According to a third aspect of the present invention there is provided a method of manufacturing an absorbent article for a wound product, the method comprising:

providing a plurality of fibres;

at least partially encapsulating the plurality of fibres within a foam matrix; and setting the foam matrix.

Suitably, the step of at least partially encapsulating comprises dispensing the foam matrix over the plurality of fibres. Suitably, the step of at least partially encapsulating comprises mixing the plurality of fibres into the foam matrix.

Suitably, the plurality of fibres are provided as a sheet of fibrous material, and wherein the sheet of fibrous material is at least partially encapsulated within the foam matrix.

Suitably, the method further comprises applying surfactant to the plurality of fibres prior to encapsulating the plurality of fibres within the foam matrix. According to a further aspect of the invention there is also disclosed a method of treating a wound using a wound product according to the second aspect of the invention.

According to yet a further aspect of the invention there is disclosed a method of providing negative pressure wound therapy to a wound, the method comprising: placing a wound product according to the second aspect of the invention over a wound; forming a fluid flow path between the wound product and a negative pressure source; and operating the negative pressure source to provide negative pressure to the wound. The aforementioned method may be performed using a negative pressure wound therapy system according to that disclosed herein.

Certain embodiments of the invention provide the advantage of improved absorbency compared to known wound products.

Certain aspects of the invention provide a wound product which better maintains absorbent capacity upon compression compared to known wound products.

Certain embodiments of the present invention provide an absorbent article having improved performance in negative pressure systems. Certain aspects of the present invention provide increased strength of a wound product, particularly when wet.

Certain aspects of the present invention provide a wound product having improved drape- ability compared to known products.

BREIF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Fig. 1 illustrates a cross-sectional view of a first example of an absorbent article;

Fig. 2 illustrates a cross-sectional view of a second example of an absorbent article;

Fig. 3 illustrates a cross-sectional view of a third example of an absorbent article; Fig. 4 illustrates a cross-sectional view of a fourth example of an absorbent article; and

Fig. 5 illustrates a cross-sectional view of an example of a wound product including the absorbent article of Fig. 1. In the drawings like reference numerals refer to like parts.

DETAILED DESCRIPTION

As used herein the expression "wound" may include an injury to living tissue that may be caused by a cut, blow, or other impact, typically one in which the skin is cut or broken. A wound may be a chronic or acute injury. Acute wounds occur as a result of surgery or trauma. They move through the stages of healing within a predicted timeframe. Chronic wounds typically begin as acute wounds. The acute wound becomes a chronic wound when it does not follow the healing stages resulting in a lengthened recovery. It is believed that the transition from acute to chronic wound can be due to a patient being immunocompromised. Chronic wounds may include for example: Venous ulcers: Venous ulcers usually occur in the legs, account for the majority of chronic wounds, and mostly affect the elderly, Diabetic ulcers (typically foot or ankle ulcers, Peripheral Arterial Disease, Pressure ulcers, or Epidermolysis Bullosa (EB)). The wound may also include a deep tissue injury. The deep tissue injury is a term proposed by the National Pressure Ulcer Advisory Panel (NPUAP) to describe a unique form of pressure ulcers. These ulcers have been described by clinicians for many years with terms such as purple pressure ulcers, ulcers that are likely to deteriorate and bruises on bony prominences.

In the following a wound product will be referred to in general terms. However, in certain examples of the present invention, the wound product is a wound dressing. Furthermore, in certain other examples of the present invention, the wound product is a wound filler. It will be appreciated that the wound product of the present invention may therefore be used as a wound dressing or a wound filler (where these uses should be considered as non- limiting), where certain examples for each use may provide further modifications specific to each particular use. Additionally, in other examples, the wound product may be a debrider or a wound cleaner. Fig. 1 shows an example of an absorbent article 100 for use in a wound product. The absorbent article 100 includes a composite composition including a foam 1 10 and a plurality of fibres 120. As used herein, the term "composite composition" may alternatively be referred to a "fibre-reinforced foam". In this example, the absorbent article 100 is a single layer absorbent article formed by the fibre-reinforced foam. In other examples, the fibre-reinforced foam may be used in combination with additional layers to form a multi- layered absorbent article.

As used herein, the term "fibre" includes relatively short fibre elements, but may also include relatively long filaments that may be formed from a continuous length of fibres.

In this example, the plurality of fibres 120 includes relatively short fibre elements (e.g. between about 2 mm and 5 mm in length). The fibre elements are loose and are distributed throughout the foam 1 10. Each of the fibres 120 are at least partially encapsulated within the foam matrix such that the foam matrix secures each of the fibres in place. As such, at least a portion of the length of each fibre element is surrounded by the foam matrix. In this way, the fibre elements are retained within the absorbent article 100.

As shown in Fig. 1 , some of the fibre elements, surface fibre elements 122, may extend partially out from a surface of the foam matrix 1 10. However, at least a portion of the length of these fibre elements 122 are encapsulated within the foam 1 10 so that they are secured in place in the absorbent article 100.

The remaining fibres, central fibre elements 124 (i.e. the fibres that do not protrude from the surface of the foam), are all fully encapsulated within the foam matrix. That is, the central fibre elements are fully surrounded by foam material. In this example, around 80 % of the plurality of fibres are fully encapsulated within the foam matrix. Aptly, between around 60 % and 95 % of the fibres may be fully encapsulated within the foam matrix.

The foam 1 10 includes cells, which may be open cells or closed cells, or in some examples the foam may include both open and closed cells. One example of a suitable foam is Allevyn® foam available from Smith and Nephew. Each fibre element may extend into, or through, at least one cell in the foam matrix. In this way, the fibre elements can function to help absorb exudate (or other fluid) that enters the cells. This can help to improve retention of exudates in the absorbent article under compression. In this example, around 50 % of the fibre elements extend into or through at least one cell in the foam matrix. It will be appreciated that the proportion of fibres that extend into, or through, at least one cell will also depend on the cell structure and cell density of the foam. Aptly, at least 20 % of the fibres extend into, or through at least one cell in the foam. More aptly, at least 40 % of the fibres extend into, or through at least one cell in the foam.

The thickness of the fibres 120 may be selected according to the desired absorbent properties of the absorbent article. As will be appreciated, higher absorbent capacity in fibrous materials can be achieved by increasing surface area of the fibres 120 (e.g. by using a greater density of smaller diameter fibres in the material). A smaller diameter equates to a smaller linear density - the measure of this in fibres is decitex (dtex). Using fibres with a smaller diameter allows a greater fibre surface area to be achieved. In this example, the fibres 120 have a linear density of around 3 dtex. Aptly, the linear density of the fibres may be less than 6 dtex, or more aptly less than 4 dtex, for example from around 2 dtex to 4 dtex. The plurality of fibres may include fibres of differing linear density or each of the fibres may have substantially equal linear density. In this example, the plurality of fibres 120 are superabsorbent polymer fibres (for example, polyacrylate or carboxyl methyl cellulose fibres). Fibres of different materials may be used in other examples to help adjust the absorbent properties and the strength of the absorbent article.

In some embodiments the plurality of fibres 120 can comprise fibre elements of between 0.8 dtex and 15 dtex. In other variations, the plurality of fibres 120 may comprise fibre elements of less than 10 dtex. Further embodiments can provide for a plurality of fibres comprising between 2 and 4 dtex or between 8 and 12 dtex. Additional embodiments can comprise a first plurality of fibres of between 2 and 4 dtex and a second plurality of fibres between 8 and 12 dtex. The absorbent capacity, the strength and the mechanical properties of the absorbent article can also be adjusted by varying the weight ratio of fibre to foam material. For example, the dry weight ratio (i.e. measured weight when dry) of fibre to foam material may be from around 10g fibre per 100g foam to around 90g fibre per 100g foam, for example from around 30g fibre per 100g foam to around 50g fibre per 100g foam.

Fig. 2 shows another example of an absorbent article 200 for use in a wound product. In this example, a plurality of fibres 220 are concentrated in a region adjacent a bottom surface 212 (i.e. wound facing surface) of the foam 210. In this example, the fibres 220 are concentrated in the volume of foam extending up to around 1 mm from the bottom surface 212 of the foam 210. In use, the bottom surface 212 may face or be adjacent to the wound bed. As such, the fibres 220 may improve wicking and absorption of wound exudate from the wound bed. Similarly to the example shown in Fig. 1 , some of the fibre elements, surface fibre elements 222, may extend partially out (i.e. protrude) from the bottom surface of the foam matrix 210. However, at least a portion of the length of these fibre elements 222 are encapsulated within the foam matrix 210 so that they are secured in place in the absorbent article 200.

The remaining fibres, central fibre elements 224 (i.e. the fibres that do not protrude from the surface of the foam), are all fully encapsulated within the foam matrix. That is, the central fibre elements 224 are fully surrounded by foam material. In this example around 10 % of the fibres are fully encapsulated in the foam matrix, and around 90 % of the fibres are partially encapsulated in the foam matrix (i.e. around 90 % of the fibres protrude from the surface of the foam, in this case the bottom surface 212).

In this example the fibres are loose superabsorbent polymer fibres, though other fibres or fibres in the form of a fibrous material as discussed below may also be used. The fibres are between around 2 mm and 5 mm in length and have a linear density of around 3 dtex.

Similarly to the example of Fig. 1 , each fibre element may extend into, or through, at least one cell in the foam. In this example, around 30 % of the fibre elements extend into or through at least one cell in the foam. This can help to ensure each of the fibre elements remain fixed in the foam matrix.

Fig. 3 illustrates a further example of an absorbent article 300. This example is similar to the example in Fig. 2, but in this example a plurality of fibres 320 are concentrated in a central region of the foam 310. As such, all of the fibres 320 in this example are fully encapsulated within the foam matrix. In other words, all of the fibres 320 are fully surrounded by the foam matrix 310.

The fibres 320 in this example are configured similarly to the fibres 220 in the example of Fig. 2, so for brevity will not be described again in detail.

In this example, the fibres 320 are concentrated in a layer about 1 mm thickness in the central region of the foam matrix and are substantially evenly distributed across the whole of the layer extending through the foam matrix. That is, the fibres are distributed over substantially the whole width and length of the foam matrix in the central region. The layer extends substantially centrally through the foam 310 such that the fibre-reinforced foam layer is substantially symmetrical in cross-section. In other examples, the layer of fibres 320 may be offset from the centre of the foam matrix 310 so that they lay closer to one surface of the foam than the other. For example, the layer of fibres 320 may be provided closer to the wound facing surface (bottom surface) of the foam. This may help to draw fluid away from the wound. The specific concentrations and location of the fibres 320 within the foam may be selected according to the desired fluid absorption and distribution properties of the absorbent article. Having the fibres 320 positioned centrally within the foam allows the foam to sit directly next to the wound in use (without intervening fibres), which can be beneficial in healing certain types of wound. In addition the wound exudate may be stored in the fibres distal from the wound, which may help to regulate moisture at the wound site. The fibres may also provide additional support and strength to the foam material.

Fig. 4 illustrates another example of an absorbent article 400. The absorbent article 400 is similar to the absorbent article 300, but in this example, the fibres 420 include loose continuous filaments of relatively longer length (e.g. at least 4 cm) extending through a central region of the foam matrix 410.

Each of the filaments 420 lay substantially parallel to each other along the lay direction of the foam 410 (i.e. substantially parallel to the top and bottom surfaces of the foam 410). Aptly, the filaments 420 extend across substantially the whole width and length of the foam matrix 410.

In this example the filaments 420 are concentrated in a layer of about 1 mm thickness in the central region of the foam and are substantially evenly distributed across the whole of the length and width of the foam. The layer extends substantially centrally through the foam 410 such that the fibre-reinforced foam layer is substantially symmetrical in cross- section. In other examples, the layer of filaments 420 may be offset from the centre of the foam 410 so that they lay closer to one surface of the foam than the other. Any of the absorbent articles described above may be manufactured according to the method shown in Fig. 6. At step 601 a plurality of fibres are provided. These may be in the form of loose fibres (including filaments) or a fibrous material (as described in more detail below).

At step 602 the fibres are at least partially encapsulated within a foam matrix. The foam matrix may be in the form of a foam formulation or mixture, which may be dispensed onto the fibres such that the foam matrix spreads in between and at least partially around each of the fibres. In another example, the fibres may be mixed into the foam matrix such that they are substantially evenly distributed (suspended) in the foam matrix.

At step 603 the foam matrix is set to form a fibre-reinforced foam including the plurality of fibres at least partially encapsulated in the foam matrix. The foam matrix is set at least partially around the fibres such that each of the fibres is secured in place by surrounding foam matrix. As discussed above, some of the fibres may protrude from the surface of the foam. As the cells in the foam develop any fibres in the region of the cells may protrude into or through the cells. Any fibres that are not at least partially encapsulated within the foam matrix during the manufacturing process will fall away from the set foam and will not form part of the fibre-reinforced foam.

Fig. 5 shows an example of a wound product 500 including the absorbent article 100 of Fig. 1. It will be appreciated that the wound product 500 may include any of the absorbent articles described herein, and is not limited to the absorbent article shown in Fig. 1 .

The wound product 500 is a negative pressure wound therapy system. As used herein, the term "negative pressure" is generally used to refer to a pressure below atmospheric pressure.

As is used herein, reduced or negative pressure levels, such as -X mmHg, represent pressure levels that are below atmospheric pressure, which typically corresponds to 760 mmHg (or 1 atm, 29.93 inHg, 101 .325 kPa, 14.696 psi, etc.). Accordingly, a negative pressure value of -X mmHg reflects pressure that is X mmHg below atmospheric pressure, such as a pressure of (760-X) mmHg. In addition, negative pressure that is "less" or "smaller" than -X mmHg corresponds to pressure that is closer to atmospheric pressure (for example, -40 mmHg is less than -60 mmHg). Negative pressure that is "more" or "greater" than -X mmHg corresponds to pressure that is further from atmospheric pressure (for example, -80 mmHg is more than -60 mmHg).

In this example, the absorbent article 100 is disposed in a wound cavity 510. A drape 520 extends over the absorbent article 100, and seals over the wound cavity 510 by an adhesive provided around the periphery 522 of the drape 520. A negative pressure interface 530, which in this example is a port provided in the drape, is coupled to a negative pressure source 540 via a tube 532. In this example, the negative pressure source 540 is a reciprocal pump. In use, the pump provides negative pressure to the wound cavity 510 via the tube 532 and the negative pressure interface 530. Negative pressure is evenly distributed through the absorbent article 100. As such, wound exudate can be drawn from the wound cavity 510 and into the absorbent article 100. The fibre-reinforced foam in the absorbent article may absorb and retain at least a portion of the wound exudate in either or both of the plurality of fibres and the foam matrix. In some examples, the wound exudate may be drawn away from the absorbent article 100 through the tube 532 and may be collected in a canister (not shown) that is located between the negative pressure interface 530 and the pump. The vacuum source or pump can be configured to deliver negative pressure of approximately -80 mmHg, or between about -20 mmHg and -200 mmHg in some implementations. The pressure range delivered by the pump can be between about -40 mmHg and -150 mmHg. Alternatively, a pressure range of up to -75 mmHg, up to -80 mmHg or over -80 mmHg can be used. Also a pressure range of below -75 mmHg can be used.

In other examples, the absorbent article may be used alone as an absorbent wound product or in combination with an attachment means (e.g. a securing bandage, an adhesive on the wound facing side of the absorbent article, or an adhesive top cover). The absorbent article may include the fibre-reinforced foam as described herein and optionally may include other additional layers. For example, in addition to the fibre-reinforced foam, the absorbent article may include at least one of additional absorbent layer(s), a wound contact layer, a moisture vapour permeable top film layer or any other suitable layers. The absorbent article may also be used as the absorbent island in an island dressing, or in combination with other wound dressing components (e.g. a perforated wound contact layer, and/or a moisture vapour permeable top film).

In some embodiments the absorbent article can be in the form of a wound dressing to be used as part of a negative pressure wound therapy system that does not include a canister for collecting exudate from the wound. The absorbent article may thus be used as part of a "canisterless" negative pressure wound therapy system that is intended to retain substantially all of the wound exudate within the wound dressing. To this end, the absorbent article may comprise superabsorbent material to enhance the absorbent capacity of the wound dressing. Furthermore, a moisture vapour permeable top film may be utilized as a cover layer to retain negative pressure under the dressing and also to promote evaporation of exudate from the dressing thereby further increasing its absorbent capacity. Polyurethane films may be suitable for such a purpose. Various modifications to the above described examples may be possible. For example, although in the examples described above, the fibres are provided as loose fibres or filaments, in other examples, the fibres may be provides as a sheet of fibrous material.

For example, the fibrous material may include fibres or filaments formed into a woven fabric, a knitted or a braided fabric, a web or a non-woven fabric. Non-woven fabrics may include fabrics formed by mechanical entanglement of the fibres or filaments, e.g. by needle punching or hydro entanglement. In some examples, the fibres may be formed as a carded non-woven web, which may include fibres of from 40 to 100 mm in length. A carded non-woven web can have a more uniform fibre alignment than other nonwoven fabrics, which can provide better flexibility and mechanical strength than other fabrics.

The sheet of fibrous material (or alternatively loose fibres) may be pre-treated with an agent (e.g. a surfactant) to help aid the spread of the foam over as many of the fibres as possible. For example, suitable surfactants may include ionic or non-ionic foaming or non- foaming surfactants.

During manufacture the sheet of fibrous material (or alternatively a plurality of loose fibres) may be placed into a casting bed, and the foam matrix may be dispensed over the sheet of fibrous material. The foam matrix will spread over the fibrous material at least partially encapsulating the fibres of the material within the foam matrix. The foam may then be set in place, and any excess foam may be cut away. This would produce a fibre-reinforced foam having the fibrous material at the bottom surface of the foam similarly to the concentrated loose fibres of Fig. 2.

In another example, a layer of foam matrix may be dispensed into a casting bed. A fibrous material (or a plurality of loose fibres) may then be placed over the layer of foam, before a further layer of foam is dispensed over the fibrous material. The foam may then be set, resulting in a fibre-reinforced foam having a fibrous material substantially fully encapsulated within the foam layer.

In other examples, the foam matrix may be injected, or suction/vacuum applied to the plurality of fibres. For example, where the plurality of fibres have a suitable level of stability (e.g. when formed as a fibrous layer), the foam mixture may be applied to a first side of the fibrous layer. To distribute the foam through the fibrous layer a vacuum or suction may be applied to a second opposite side of the fibrous layer to draw the foam mixture through the fibrous layer such that the fibres are at least partially encapsulated in the foam matrix.

In some examples, the fibres may be suspended in a gas or liquid phase prior to encapsulation in the foam. In this example, the plurality of fibres may be suspended in a liquid prior to the foam formulation being added. As the foam formulation is added, it displaces the liquid, leaving the plurality of fibres encapsulated in the foam matrix.

In some examples, the set foam including the plurality of fibres may be cut to the desired thickness.

Although in the examples described above, the fibres are superabsorbent polymer fibres, in other examples, the plurality of fibres may include at least one of viscose fibres, superabsorbent fibres, carbon fibres, synthetic fibres, natural fibres, bio-resourced or recycled fibres. A combination of two or more different types of fibre may also be used. This can help to adjust the absorbent properties of the fibre-reinforced foam. For example, a blend of fibres including around 70 % viscose and 30 % PET fibres could be used. The ratio of viscose fibres to PET fibres can be adjusted according to desired properties of the fibre-reinforced foam. For example, increasing the percentage of PET fibres would help to increase strength, whereas increasing the ratio of viscose or superabsorbent fibres would improve absorbency.

With the above described examples having the fibres at least partially encapsulated in the foam matrix, the risk of fibres becoming loose from the article may be reduced, whilst also improving the absorbent properties.

The fibres may absorb and help to retain wound exudate that is drawn into the foam. This can help to store the fluid away from the wound bed and thereby reduce risk of

maceration. The fibres can provide additional strength to the foam material and in particular may increase strength of the foam in a wetted condition. This can help to prevent tearing of the dressing in use. Furthermore, the additional strength provided by the fibres can help to prevent collapse of the absorbent article when used in a negative pressure device (e.g. as wound filler). Thus, the absorbent article may be particularly suitable for distributing negative pressure to a wound site whilst also functioning as an absorbent element for storing wound exudate from the wound. The examples described above can also better retain absorbent properties when under compression. This can therefore help prevent leaking of the wound dressing in use. The absorbent articles described above have the advantage that the article can be cut to size. Since the fibres are at least partially encapsulated in the foam matrix, the fibres are fixed in place and so risk of fibres becoming loose when cutting the article is significantly reduced compared to a known fibrous wound dressing. Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.