The present invention relates to a diagnostic or testing device, a consumable device for use with the diagnostic device and a method of operating both the diagnostic device and consumable device.

There is a requirement for an easily operable means to perform certain diagnostic tests, where an operator is not required to possess advanced skills and where a result of the tests can preferably be obtained in-situ (i.e. without being sent to a laboratory for analysis) in a relatively short timeframe.

In a particular scenario, a patient’s urine may be analysed for the presence of certain pathogens. This analysis typically involves collecting a sample from the patient and then dispatching the sample to a laboratory for analysis and waiting for the results to be returned. This can take valuable time, which could otherwise be used to begin treatment and so alleviate the patient’s condition.

In a particular example, it is desired to detect pathogens indicative of a urinary tract infection (UTI) in a urine sample, and to ascertain the antimicrobial sensitivity thereof.

Urinary tract infections can be very painful, cause significant distress and may have serious consequences if left untreated. Unfortunately, many vulnerable patients are unable to recognise the symptoms of an infection or articulate their discomfort. UTIs are common in residents of care homes for the elderly or infirm. People who have urinary tract infections may become confused, angry or delirious. However, such symptoms may be difficult to distinguish from those of other conditions that may also be present, for example dementia.

Even when a UTI is suspected it can be difficult and slow using current methods to identify the specific pathogen causing the infection or the antimicrobial sensitivity of that pathogen. This can cause delays in a patient receiving the correct treatment, leading to prolonged suffering and an increased risk of complications.

It is an aim of embodiments of the present invention to address shortcomings and issues in the prior art, whether mentioned herein or not.

According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows. According to a first aspect of the present invention, there is provided a system comprising a diagnostic device and a cartridge, wherein the diagnostic device is operable to receive the cartridge, having a plurality of chambers, each of which plurality of chambers is arranged to contain a fluid sample for analysis, wherein the diagnostic device is further operable to: agitate the cartridge; incubate the fluid samples contained in the respective plurality of chambers; measure optical transmission through each of the plurality of chambers, each including a respective fluid sample, in order to determine an attenuation measurement, wherein if the attenuation measurement in any particular one of the plurality of chambers differs from a threshold value by a defined amount, then a positive result in connection with the particular one of the plurality of chambers is indicated to a user.

In an embodiment, agitation of the cartridge is achieved via rotation, vibration or shaking.

In an embodiment, the threshold value is determined on the basis of: one or more of the properties of the contents of one or more of the plurality of chambers; and an attenuation measurement determined on the basis of a control sample included in one of the plurality of chambers.

In an embodiment, wherein the optical transmission is determined using an optical source, which produces an optical signal, and an optical receiver. In an embodiment the wavelength of the optical source is selected according to the chemistry employed in the cartridge.

In an embodiment, the optical signal passes through each of the plurality of chambers individually so that the optical signal is received by the optical receiver.

In an embodiment, there is provided an identification reader for reading an identifier associated with the cartridge.

In an embodiment, the device is operable to display the positive result to the user by means of a Display/UI.

In an embodiment, there is provided a communications unit to allow results to be communicated to an associated device.

In an embodiment, the cartridge is arranged at an angle in the range of substantially 5° -45° relative to a base of the diagnostic device. Most preferably, the cartridge is arranged at an angle of substantially 25-30° relative to a base of the diagnostic device. According to a second aspect of the present invention, there is provided a cartridge for use in a diagnostic device, the cartridge comprising: a sample entry port leading to a cavity for receiving a fluid sample; a distribution nozzle in selective fluid communication with the cavity; a plug to prevent fluid communication between the cavity and the distribution nozzle; and a plurality of sample chambers to each receive some of the fluid sample from the distribution nozzle, wherein the cartridge is operable such that the plug may be manoeuvred to permit the fluid sample to flow into the distribution nozzle and then into the plurality of sample chambers.

In an embodiment, the plug is manoeuvred by the relative screwing or unscrewing of an upper and lower part of the cartridge.

In an embodiment, the distribution nozzle is arranged to dispense substantially equal amounts of the fluid sample into each of the plurality of chambers.

In an embodiment, there is provided an air escape channel which permits air in the plurality of sample chambers to vent to an exterior of the cartridge upon entry of the fluid sample into the plurality of sample chambers.

In an embodiment, there is provided an identifier for reading by an associated diagnostic device.

In an embodiment, each of the plurality of sample chambers is pre-supplied with at least one or more of: a nutrient; an antibiotic; and a dye.

According to a third aspect of the present invention, the system of the first aspect comprises the cartridge of the second aspect.

Although a few preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example only, to the accompanying diagrammatic drawings in which:

Figure 1 shows a general view of a diagnostic device according to an embodiment of the present invention; Figure 2 shows a partial internal view of the device of Figure 1 ;

Figure 3 shows a general view of a consumable device or cartridge according to an embodiment of the present invention;

Figures 4a-c show cross-sectional views of the device of Figure 3 in various stages of operation;

Figure 5 shows an exploded view of the device of Figure 2;

Figures 6a-6l show a sequence of operations of the use of a diagnostic device according to an embodiment of the present invention and a consumable device according to an embodiment of the present invention;

Figure 7 shows a schematic of the major functional units of the device of Figure 1 ;

Figure 8 shows a detailed view of a cartridge receiver, forming part of the device of Figure 1 ; and

Figure 9 shows details of an optical scanner, forming part of the device of Figure 1 .

Figure 1 shows a general view of a diagnostic device 1 according to an embodiment of the present invention. The device 1 is arranged for use in a desktop setting, rather than a laboratory setting, although it could, of course, be so used if required.

The device 1 comprises a cover 10 which is openable to reveal an internal portion of the device, which is arranged to receive a consumable device, which is described later. The device 1 also comprises a display 20, which is operable to display status and result information to the user.

The device 1 is operable to analyse a sample included in the consumable device and its operation will be described in more detail later.

Figure 2 shows a partial internal view of the device 1 , with the outer casing and cover 10 removed. A cartridge-receiver 30 is shown, which is operable to receive the consumable device 100.

Figure 3 shows a consumable device 100, arranged to be used in conjunction with the diagnostic device 1 , shown in Figure 1 . In the following description of Figures 3 to 5, further details of the cartridge 100 are provided, together with a step-by-step description of its operation from unpacking to being placed into the diagnostic device 1.

The consumable device 100, hereinafter also referred to as a cartridge, is arranged to receive a sample for analysis. The sample for analysis is introduced into the cartridge through a sample port, which is here shown covered by a lid 105. The sample, once introduced, passes through the body of the cartridge and is distributed evenly into a plurality of separate chambers 110.

Figure 4a shows the cartridge 100 in cross-section and reveals details of its internal operation. This figure is best viewed in conjunction with Figure 5 which shows an exploded view of the features of the cartridge 100. In Figure 4a, the cartridge 1 is shown with a diluent in-situ after the sample has been introduced via sample port 106.

The upper portion 115 of the cartridge houses a sample entry port 106, which is provided with a lid 105, attached to the port by means of a screw thread provided on an external surface of the port 106 and a complementary thread on an internal surface of the lid 105. The entrance to the port 106 is sealed with a removable seal 116, which is provided for biosecurity reasons, so that a user of the cartridge can be assured that the cartridge is new and has not been tampered with. The seal 116 takes the form of a peel-off foil or similar material. In some circumstances a seal may not be required and so this is to be considered as an optional feature.

The upper surface 115 forms an upper boundary to a cavity 121 formed from chamber unit 120. The chamber unit 120 is substantially cylindrical and defines the cavity 121 such that the cavity has a smaller diameter at its base than at the upper end, covered by upper portion 115. Extending downward from the chamber unit 120 is an internally threaded portion 122, arranged to couple in a screwed manner with distribution nozzle 130, which is provided with a complementary threaded external portion 131.

Positioned between the chamber unit 120 and the distribution nozzle 130, there is provided a primary seal 125 which provides a barrier between chamber unit 120 and distribution nozzle 130.

At the base of the chamber unit 121 , there is provided an aperture 123 which, once opened, allows the sample (and diluent, if present) to flow into the distribution nozzle 130. In the state shown in Figure 4a, the aperture is closed by plug 134 which extends upwardly from, and is integrally formed with, the distribution nozzle 130. The plug 134 comprises an o-ring or gasket 134a which sits within a circumferential groove in the plug 134 and serves to ensure that any fluid in the cavity 121 remains in place until such time as it is permitted to escape.

In order to cause the fluid contained in cavity 121 to escape into the distribution nozzle, the chamber unit 120 is rotated relative to the distribution nozzle 130, causing the chamber unit 120 to move relatively upward, away from the distribution nozzle 130, by means of the complementary threaded portions 122, 131.

Once the upper portion 120 has been unscrewed as described, the cartridge is as shown in Figure 4b. Here, the fluid in the cavity 121 is in the process of flowing downwards under gravity into the distribution nozzle 130 and thence into the plurality of separate chambers 110. The distribution nozzle serves to ensure that a substantially equal amount of fluid flows into each individual chamber 110.

Unscrewing the upper portion as described also opens the air escape channel 133, which is a vent which is closed until the upper half is unscrewed. The air escape channel allows air which is displaced from the chambers 110 by the entry of fluid to escape to the exterior of the cartridge. In the absence of the air escape channel, the fluid would not leave the cavity since it would be a closed system.

Once all the fluid has left the cavity 121 and each of the chambers 110 has been filled to the requisite level, the cartridge can be sealed so that the fluid in each chamber 110 cannot escape. To this, the unscrewing operation referred to previously is reversed, whereby the upper section 120 is screwed such that it travels by means of complementary screw threads 122, 131 towards the plurality of chambers 110. Figure 4c shows the final configuration, once the screwing operation is complete. Here the plug 134 is again located in the aperture 123. Further, there is no air escape possible from the cartridge, since air escape channel 133 is closed off, further preventing any flow of fluid from the chambers 100.

Figures 6a-l illustrate the mode of operation of the cartridge 100 from before the introduction of the sample up to insertion of the cartridge 100 into the diagnostic device 1 and provide supplementary information to that provided above in relation to Figures 3-5.

Figure 6a shows the cartridge 100 ready for first use. The cartridge 100 is supplied to the user, preferably in a shrink-wrapped plastic film 200 to ensure the cartridge is protected and to assure the user that it has not been pre-used or otherwise tampered with. The film 200 is removed before use. Figure 6b shows how the upper surface of the cartridge 100 may be labelled with a patient’s details or other identifier to link the particular cartridge to the particular patient. A pre-printed area may be provided on the cartridge. Alternatively, space may be provided for a printed label to be affixed thereto.

Figure 6c shows the lid 105 being unscrewed ready for use. The lid 105 is required later and is retained for further use. The protective seal 116, if present, is also removed before use and may be discarded.

Figure 6d shows a sample being drawn up into a syringe 300 from a container 310. In a specific example, the sample is a urine sample. In other examples, the sample may be peritoneal fluid or ascitic fluid. A defined volume of fluid is required for the later analysis and this is the volume drawn up at this time.

Figure 6e shows the sample being delivered into the cartridge from syringe 300 by means of port 105. Once the requisite volume has been delivered, the lid 105 is re-applied and tightened. An interior portion of the port 106 is provided with internally projecting ribs which guide the syringe tip and also provide means for displaced air to leave the cavity 121 as the sample is delivered. The cavity 121 inside the cartridge may be pre-supplied with a diluent.

Figure 6f shows the cartridge being agitated, which can be achieved by inversion. This step is required if the cartridge has been pre-supplied with cavity 121 containing a diluent, which is required in certain embodiments of the invention. A suitable diluent is water or a phosphate- buffered saline solution. If no diluent is required, then step 6f may be omitted. For instance, the sample may not require dilution or may be diluted before being introduced into the cartridge.

Figure 6g shows the cartridge being placed on a level surface. Note that the sample (plus diluent, if present) is retained within cavity 121. In order to release the sample, as shown in Figure 6h, the chamber unit 120 is unscrewed (moved upwards), which releases the sample (plus diluent, if present) into the distribution nozzle 130. By unscrewing the chamber unit 120 in this way, air escape channels 133 are opened, which permits the sample to flow freely, as the air displaced by the entry of the sample is then able to escape. Figure 6i shows the sample flowing from cavity 121 via the distribution nozzle 130, which serves to ensure that each of the plurality of chambers 110 is filled to a substantially identical level, so that each contains a substantially identical volume. The respective fill level of each chamber 110 can be judged by eye. Figure 6j shows the chamber unit 120 of the cartridge being fully screwed into its original starting position, which has the effect of sealing the cartridge and preventing any sample from escaping. In particular, screwing the chamber portion downwards in this way has the effect of closing the air escape channels 133, thereby preventing any liquid from escaping from the cartridge. A security feature may be employed whereby a click is heard upon reaching the end of the screw operation, where the click is the result of a mechanical lock engaging which prevents the cartridge from then being unscrewed.

Figure 6k shows the final state of the filled cartridge 100 after the sample has been introduced and been distributed to the plurality of chambers 110. After this, it is ready for the analysis process to begin.

Figure 6I shows the cartridge being introduced into the diagnostic device 1 .

Figure 7 shows a block diagram illustrating certain functional units of the device 1.

The device 1 comprises a power supply 510 for powering the various units of the device. The power supply is preferably a mains AC power supply, but in some embodiments, an internal DC power supply may be provided if, for instance, the device is to be used in the field, where a suitable mains supply may be unavailable. In either case, suitable power conditioning is provided so that the required voltages are supplied to the various units of the device.

At the heart of the device is a processor 520. The processor controls the operation of the device, using a program stored in memory 530. The memory 530 is also used as working memory for the processor. The program for operating the device is pre-stored in the memory and is made available at power-up. If the program requires updating periodically, this may be achieved via a connection to a suitably programmed computer via, for instance, a wired or wireless connection (not shown).

The operation and control of the device 1 is performed by means of the display/User Interface (Ul) 580. An important aspect of the device 1 is that it should be simple to operate and not require extensive user training. As such, the display and control are deliberately kept simple. The user is able to begin the analysis process by selection of a suitable menu option from the display and then operating a control. Alternatively, a single “Start” button may be provided to begin the analysis. If it is required to stop the analysis this same button may be pressed again.

The progress of the analysis can be displayed on the display and once the analysis is complete, the results can be displayed here also. To further enhance the operation of the device 1 , the cartridge 100 may be provided with a form of identification which may be read by the device 1 via ID reader 590. The ID may be in the form of a bar code or QR code, which is able to read optically. More preferably, an RFID tag is used, which can be read by means of a suitable RF reader.

Each cartridge may then be assigned either a unique ID, or one of a predefined range, wherein each ID in the range corresponds to a particular selection of antibiotic substances provided in the plurality of chambers 110. In either event, the processor is able to provide a meaningful display message to the user to indicate which antibiotic is most suitable at the end of the test.

A Communications unit 600 may be provided which permits results to be sent from the device 1 to a remote device. The remote device may be, for instance, a WiFi Access Point AP (not shown) which links the device to a remote medical records system where the results may be automatically added to a patient’s records. The patient’s details may be obtained by reference to the ID referred to above. Other communications techniques may be used. For instance, Low Power RF, such as Bluetooth, may be used to link the device 1 to a nearby computer which can either store the results locally or transmit them to a remote system for storage.

In any event, any communications are suitably encrypted to ensure confidentiality.

In more detail, the analysis involves the cartridge 100 being incubated at a given temperature, agitated/rotated for a time and optical measurements being made periodically. As such, the incubator 540 comprises temperature control means to keep the sample in the cartridge at or about body temperature (approximately 37° Celsius). The temperature control means typically comprises a heater to raise the sample above normal room temperature. It may also comprise a cooling device if the device is likely to used in warmer ambient conditions.

Once introduced into the device 1 , the cartridge 100 is rotated to ensure that the fluid sample included in each of the chambers 110 is mixed thoroughly with a capsule 140 included in each of the chambers.

The number and speed of rotations required in order to ensure full and consistent mixing may be varied depending upon the exact circumstances, but in a preferred embodiment, the speed of rotation may be in the range of 7.5 to 200rpm and 2 to 20 rotations may be required. More preferably, a speed in the range of 120-200rpm is preferred.

The rotations may be continuous or there may be one or more brief pauses at intervals. The direction of rotation may be always in the same direction, or it may be alternated. The alternation may follow one or more of the brief pauses. Each capsule 140 in each chamber is different and comprises a different antibiotic, a nutrient and an indicator compound whose colour is dependent on the presence or absence of bacteria. The capsule typically comprises a soluble shell with powered ingredients included therein. Alternatively, a compacted power tablet or a liquid solution may be provided.

It is found that angling the cartridge at an angle of approximately 5° - 45°, more preferably at 15° - 35° and most preferably at 25° - 30°, relative to a line perpendicular to the base of the device and leaving a small quantity of air in each chamber at the filling stage ensures optimal dissolving of the capsule in the fluid sample.

Each capsule comprises a different antibiotic and indicator compound. As the analysis process progresses, a certain defined colour change is triggered which is detectable by means of the optical scanner 570. The exact nature of the colour change is not an aspect of the present invention and any means by which a suitable change in colour of the various samples can be assessed would be of utility. However, for details of a typical technique, reference is invited to the Applicant’s co-pending patent application W02019/063990A1 .

As can be seen most clearly in Figures 3 and 4, there is a central open area provided between the plurality of chambers 110. This central open area coincides with an optical source in the device 1. Figures 8 and 9 illustrate features of the optical scanner and how this interacts with the cartridge 100.

Figure 8 shows how the cartridge 100 is received into the cartridge receiver 30. The cartridge receiver is sized to complement the cartridge 100 and is provided with a plurality of inwardly extending ribs 572 which align with the gaps between the plurality of chambers 110 in the cartridge. In this way, the cartridge is held securely in position and the neighbouring chambers 110 are optically isolated from each other. In the outer wall of the cartridge receiver 30, there are provided a number of apertures 573, each one associated with one of the plurality of chambers 110. These apertures 573 allow an optical detector 575 (shown in Figure 9) to receive light emitted from a central source 574, having passed through the sample in the respective chamber 110. The optical source is preferably a Light Emitting Diode, LED emitting light at a wavelength in the region of 540nm. Of course, the optimum wavelength to select depends upon the nature of the colour change expected in the sample fluids in plurality of chambers, and 540nm is an example of the wavelength associated with a particular chemical composition. More generally, a wavelength in the range of 500 to 600nm is suitable. Other compositions may be associated with other wavelengths. An LED power in the range of 60 to 100mW is preferred. Figure 9 shows a sectional view through the cartridge receiver 30. The inwardly extending ribs 572 can be clearly seen, as well as the optical source 574 which is positioned in the central gap between the plurality of chambers 110. Light from the optical source 574 passes through the fluid sample in chamber 110, travels along path 576, and emerges via aperture 573, where it falls upon an optical detector 575, in the form of a photodiode.

The light emitted from the optical source 574 is of a known wavelength and the optical receiver 575 is similarly receptive to light of this wavelength. By passing through the sample, a degree of attenuation of the optical signal is experienced. This attenuation is at least partly dependent on the colour and/or opacity of the liquid in the respective chamber.

In an embodiment, once the interaction between the sample and the capsule 140 has progressed, one possible outcome is the generation of a compound having a particular defined colour in the solution. The presence of such a colour is indicative of a particular interaction having taken place. In one embodiment of the present invention, the absence of the defined colour is indicative of the suitability of a particular antibiotic to treat the patient whose sample is being tested. In the presence of a suitable concentration of coloured compound in the sample, the optical signal received by the optical receiver 575 is attenuated to such a degree that the signal received at optical detector 575 is below a defined threshold. This is indicative of the inefficacy of the antibiotic included in the particular capsule 140 in that chamber and so the processor 520 controls the display/UI 580 to display a suitable message to the user. If the antibiotic in a particular chamber is effective, then the defined colour is not produced, or at least not produced to a significant extent, and this is indicative of the efficacy of that particular antibiotic.

The defined threshold may be an absolute threshold, defined for the particular situation, taking into account the nature of one or more of the sample type, the antibiotic type and the nutrient type. Alternatively, the threshold may be defined to be relative to a change (or lack thereof) in the colour of a fluid in one of the plurality of chambers 110 designated as a control. In this control chamber, a colour change is experienced, since there is no antibiotic activity, and so this can serve as a baseline whereby the significant absence of a colour attributable to the indicator in the remaining chambers can be safely attributed to the action of antibiotic, nutrient and indicator.

In a particular example, the coloured compound used is tetrazolium violet, which demonstrates maximal light absorption at 540nm, although there is a degree of absorption in the range 500 to 600nm. The optical source 574 and detector 575 are therefore configured to operate at this wavelength. Other compounds will have different properties and the optical source/detector pair can be configured accordingly. In some cases, the source and detector can be configured to have a relatively broad range of emission/detection wavelengths, allowing the apparatus 1 to operate with a range of possible compounds.

A single optical detector 575 may be provided, with the cartridge being stepped around, exposing each of the plurality of chambers in turn. Alternatively, a plurality of optical detectors 575 may be provided, each associated with an aperture 573 and chamber 110 so that simultaneous readings may be taken.

In use, the cartridge 100 may be continuously rotated during the testing procedure, stopping only to perform the measurements set out above. Alternatively, the cartridge may be rotated for a defined period before resting for a further period, with this pattern being repeated as necessary, taking into account the speed and number of rotations referred to previously. The rotation is controlled via the rotator controller 550, under instruction from the processor 520. The rotator controller provides control signals to the rotator 560, which includes a motor arranged to rotate the cartridge receiver 30 and. Hence, the cartridge 100.

In another embodiment, the cartridge 100 need not be rotated and can, instead or as well, be agitated, shaken or vibrated. The purpose of the rotation or alternative process is to ensure that the contents of the plurality of chambers are well mixed so that the chemical reactions which are sought can progress as required. In the present application, reference is mostly made to rotation, but the skilled person will realise that agitation, vibration or shaking yield similar results by similar means and so this should be borne in mind when reference is made to rotation.

As can be seen in Figure 2, the cartridge is inclined at an angle of approximately 25° to the vertical. This angle is found to give a good degree of mixing of the solution in each chamber, which assists in the dissolution of the capsule 140 and the subsequent reaction. This mixing is further enhanced by the provision of a small amount of air at the top of each chamber, so that as the cartridge 100 rotates, room is provided for agitation. The amount of solution in each chamber is controlled by virtue of the amount of sample introduced into the cartridge, together with the amount of diluent, if provided.

In use, the incubation and associated rotation of the cartridge 100 may continue for a predefined period of time, with tests of each chamber being taken periodically. Alternatively, the incubation and rotation may only continue until such time that one of the chambers produces a positive result, as set out above. A default maximum time may be configured such that if no positive result is triggered by such a time, the analysis is terminated, and a suitable message displayed to the user via the Display/UI 580.

Once the test is completed, the processor unlocks the cover 10, allowing the cartridge 100 to be withdrawn and disposed of or recycled. The cartridge receiver 30 can also be removed for cleaning, if necessary. This may be the case if a cartridge leaks any sample fluid during the test.

At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as ‘component’, ‘module’ or ‘unit’ used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term “comprising” or “comprises” means including the components) specified but not to the exclusion of the presence of others.

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.

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. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). 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.