VIAL ADAPTOR

A vial adaptor is disclosed. The vial adaptor can include a cap member and a piston. The cap member can removably couple to a vial storing, for example, liquid constituent for facilitating sample collection for detecting pathogens. The piston can distally translate through the cap member and into the vial to generate volume displacement and positive pressure, which can cause the liquid constituent stored in the vial to flow out from the vial via a channel formed within the piston. The piston can include a cover that creates a water-tight seal with an inner surface of the vial.

FIELD

The present application is generally related to a vial adaptor for transferring materials, such as a fluid containing a biological sample, from a vial to another device such as, a cartridge for sensing and/or identifying pathogens, genomic materials, proteins, and/or other small molecules or biomarkers.

BACKGROUND

Pathogens may be identified by detecting genomic material (DNA or RNA) in a biological sample. In conventional nucleic acid testing (“NAAT”), DNA in a biological sample is exponentially copied using a molecular amplification processes such as, the polymerase chain reaction (“PCR”) or Loop-Mediated Isothermal Amplification (“LAMP”) until the quantity of DNA present is great enough to be measurable. In the case of RNA, the genomic material of many viruses, an additional step can be included to first transcribe the RNA into DNA before amplification. Liquid constituents such as amplification reagents, buffer solutions, water, mucin mitigating agents, or other desired liquid constituents are typically used in the testing processes, some of which assist in extracting the DNA, RNA or both from a target agent present in the biological sample such as, mold, fungus, bacteria, virus, or a microbe. These liquid constituents need to be efficiently introduced into devices that facilitate NAAT, especially in situations where pipettes are not readily available. There is a lasting need for improved pathogen detection methods and tools, which facilitate the transfer of biological samples and liquid constituents into devices that are used for NAAT.

SUMMARY

According to one aspect of the disclosure, a vial adaptor that can facilitate transfer of fluid from a vial to a receiving device is disclosed. The vial adaptor can include a cap member comprising a proximal opening, a distal opening, and a threaded portion that can removably couple with a corresponding threaded portion formed on an opening of a vial; a piston including a cover, a distal end, a proximal end, a channel, and a body extending between the distal end and the proximal end and comprising a head, the cover can surround the head and abut an inner surface of the vial, the channel extending between the distal end and the proximal end of the piston and configured to allow flow of fluid through the piston between the distal end and the proximal end; a ratchet system including: a first arm formed about the proximal opening of the cap member, at least a portion of the first arm extending inward towards a center of the proximal opening of the cap member, the first arm including a tip; and a first rack formed along the body of the piston, the first rack can engage the first arm, wherein the engagement between the first rack and the first arm allows the piston to translate in a first direction, and wherein a translation of the piston in the first direction can cause a positive pressure change in the vial and withdrawal of fluid stored in the vial through the channel of the piston.

In some embodiments, the first direction can be a direction towards the vial.

In some embodiments, the engagement between the first rack and the first arm can prevent the piston from translating in a second direction.

In some embodiments, the second direction can be a direction away from the vial.

In some embodiments, the channel can include a proximal aperture and a distal aperture, the channel extending between the proximal aperture and the distal aperture, the distal aperture formed on a distal portion of the head of the body of the piston, the proximal aperture formed about the proximal end of the piston. The cover can include an opening that aligns with the proximal aperture of the channel, and wherein the fluid stored in the vial flows into the piston via the opening of the cover and the proximal aperture of the channel.

In some embodiments, an outer circumference of the cover can create a seal with the inner surface vial. The cover can be a molded elastomer.

In some embodiments, the first rack includes a plurality of tooth, and wherein each of the plurality of tooth includes a leading edge and a stopping edge. The leading edges of the first rack facilitates movement of the first arm, and wherein the stopping edges of the first rack prevents movement of the first arm. The first arm slides along the leading edges of the first rack when the piston is translated in the first direction, and wherein the first arm abuts against one of the stopping edges of the first rack when the piston is translated in the second direction.

In some embodiments, the proximal end of the piston removably can couple with a receiving device.

In some embodiments, the piston can include a stopper extending radially and circumferentially outwards from the body of the piston, wherein the stopper can abut the cap member when the piston is in its distal-most position with respect to the cap member.

In some embodiments, a width of the channel can increase from the distal end of the piston to the proximal end of the piston.

In some embodiments, the tip of the first arm can be curved inwards towards an axis orthogonal to the proximal opening and the distal opening.

In some embodiments, the vial adaptor can include: a second arm; and a second rack formed along the body of the piston and configured to engage the second arm. The second arm can be positioned opposite of the first arm, and wherein the second rack can be formed on an opposite side of the body of the piston.

According to another aspect of the disclosure, a vial adaptor is disclosed. The vial adaptor can include: a cap member that can removably coupled with an opening of a vial; and a piston including a distal end, a proximal end, a body extending between the distal end and the proximal end, and a channel, the channel can allow flow of fluid through the piston between a distal aperture formed on the distal end of the piston and a proximal aperture formed on the proximal end of the piston, the piston can translate distally through the cap member and towards the vial, wherein a distal translation of the piston can cause a positive pressure change in the vial and withdrawal of fluid stored in the vial through the channel of the piston.

In some embodiments, the cap member can include an arm, wherein the piston can include a rack, and wherein the arm can engage the rack to allow the piston to translate distally through the cap member towards the vial and prevent the piston to translate proximally through the cap member away from the vial. The arm can include a tip, and wherein the tip can be curved inwards towards an axis parallel to the body of the piston. The rack can include a plurality of tooth, wherein each of the plurality of tooth can include a leading edge and a stopping edge, and wherein the arm can slide along the leading edges of the plurality of tooth and the piston can be translated distally and abut one of the stopping edges of the plurality of tooth to prevent the piston from translating proximally.

In some embodiments, the proximal end of the piston can be removably coupled with a receiving device.

In some embodiments, the piston can include a stopper extending radially and circumferentially outwards from the body of the piston, wherein the stopper can abut the cap member when the piston is in its distal-most position with respect to the cap member.

In some embodiments, a width of the channel can increase from the distal aperture to the proximal aperture.

In some embodiments, the tip of the first arm can be curved inwards towards an axis orthogonal to the proximal opening and the distal opening.

In some embodiments, the vial adaptor can include a cover, wherein the cover can cover the distal end of the body of the piston. The cover can be a molded elastomer. The cover can abut an inner surface of the vial to create a seal between the cover and the inner surface of the vial.

According to another aspect of the disclosure, a piston for withdrawing fluid stored in a vial is disclosed. The piston can include: a distal end; a proximal end; a body extending between the distal end and the proximal end, the body including a head including a distal aperture, the proximal end including a proximal aperture; a channel formed within the body and extending between the distal aperture and the proximal aperture; the head of the piston that can move towards and into a vial and generate a positive pressure change in the vial, thereby causing a flow of fluid stored in the vial into the channel via the distal aperture and out of the channel via the proximal aperture.

In some embodiments, a width of the channel increases from the distal aperture to the proximal aperture.

In some embodiments, the piston can include a rack comprising a plurality of tooth. The rack can be formed along a length of the body of the piston. Each of the plurality of tooth can include a leading edge and a stopping edge. The leading edges of the plurality of tooth can allow an arm of a cap member to slide along in a first direction, and wherein the stopping edges of the plurality of tooth can prevent the arm of the cap member from moving in a second direction opposite from the first direction.

In some embodiments, the piston can move through a proximal opening and a distal opening of a cap member, and wherein the cap member can be attached to an opening of the vial.

In some embodiments, the cap member can be positioned between the piston and the vial.

In some embodiments, the piston can include a cover. The cover can cover the distal end of the piston, and wherein an outer circumference of the cover can abut an inner surface of the vial to create a seal between the cover and the vial. The cover can be a molded elastomer.

In some embodiments, the proximal end of the piston can removably couple with a receiving device.

According to another aspect of the disclosure, a method of withdrawing fluid stored in a vial via a vial adaptor is disclosed. The method can include: coupling a distal opening of a cap member of a vial adaptor to an opening of a vial, the cap member including a proximal opening opposite of the distal opening; coupling a proximal end of a piston of the vial adaptor to an opening of a receiving device; distally translating the piston towards the vial and through the proximal opening and the distal opening of the cap member, a head of the piston can abut an inner surface of the vial to create a water-tight seal between the head of the piston and the inner surface of the vial, a distal translation of the piston towards the vial can generate positive pressure change in the vial and cause a flow of fluid stored in the vial.

In some embodiments, the head of the piston can be a molded elastomer.

In some embodiments, the cap member can include an arm and the piston can include a rack having a plurality of tooth, and wherein the arm of the cap member and the plurality of tooth of the piston can engage during the distal translation of the piston.

In some embodiments, each of the plurality of tooth of the rack can include a leading edge and a stopping edge, wherein the arm slides along the leading edges of the plurality of tooth of the rack during the distal translation of the piston, and wherein the stopping edges of the plurality of tooth of the rack can prevent a proximal translation of the piston away from the vial.

In some embodiments, the piston can include a channel extending between a distal aperture formed about a distal end of the piston and a proximal aperture formed about the proximal end of the piston.

In some embodiments, the piston can include a stopper. The stopper can abut the cap member when the piston is in its distal-most position. The stopper can abut the receiving device when the proximal end of the piston is coupled to the opening of the receiving device.

DETAILED DESCRIPTION

Aspects of the disclosure herein concern an adaptor that facilitates the flow of liquid constituents from a standard vial to a target sensing device or a diagnostic device e.g., a cartridge configured to detect a pathogen. The adaptor may be coupled to a standard vial and a standard target sensing device without any modification to the vial or the target sensing device. In some aspects, the adaptor is configured to inhibit or prevent re-aspiration of the liquid constituent into the vial.

FIGS.1A and1Billustrate various views of an example vial adaptor100. The vial190can be, in some embodiments, an off-the-shelf vial or the vial can be specifically or custom manufactured. The adaptor100can include a cap member110and a piston150. The cap member110can be removably coupled to a vial190during use and can be decoupled after use. For example, the vial190can include a threaded or interlocking portion290(an example is shown inFIG.2), which corresponds to a threaded or interlocking portion620of the cap member110. The piston150can be slidingly inserted into a cavity formed by the cap member110and translate towards the vial190through the cap member110. In some embodiments, the cap member110can include a locking mechanism that allows the piston150to only translate distally (for example, towards the vial190) and not proximally (for example, away from the vial190). The movement of the piston150(for example, distal translation through the cap member110towards the vial190) can generate a positive pressure and cause fluid stored in the vial190to flow out of the vial190through the vial adaptor100.

The piston150can include a proximal end (for example, an end opposite the vial190as shown inFIG.1A) that can removably couple with an opening of a target sensing device or a diagnostic device (for example, seeFIGS.8A and8B).

FIG.2illustrates an exploded view of the vial adaptor100and the vial190. The cap member110can include a distal end214(for example, an end that is proximate to the vial190) and a proximal end216(for example, an end that is distal from the vial190). The proximal end216can include an opening dimensioned to receive the piston150. The distal end214can include an opening dimensioned to couple with the vial190. For example, the distal end214of the cap member110can include an inner surface having the threaded portion620(seeFIG.6B). Additionally, the distal end214of the cap member110can extend over at least a portion of the threaded portion290of the vial190when coupled to the vial190. The coupling between the vial190and the cap member110can be leak-proof to prevent or inhibit fluid stored in the vial190from leaking during the transfer process.

The vial190can include the threaded portion290and a protrusion292. The protrusion292can engage the distal end214of the cap member110and stop further distal translation of the cap member110.

The piston150can include a cover200and a body220. The cover200and the piston body220can be removably coupled. The cover200can include a base202and a tip204. The base202that can be dimensioned such that its outer circumference206can abut against an inner surface (for example, inner surface710shown inFIG.7A) of the vial190to create a seal. The seal between the inner surface710of the vial190and the outer circumference206of the base202can be maintained while the piston150is distally translated through the cap member110towards the vial190. Additionally, the seal between the inner surface710of the vial190and the outer circumference206of the base202can prevent or inhibit fluid stored in the vial190from leaking between the base202of the cover200and the inner surface710of the vial190during use. Additionally, the seal between the inner surface710of the vial190and the outer circumference206of the base202can generate a positive pressure gradient or volume displacement in the vial190, which can cause fluid stored in the vial190to flow out of the vial190via the vial adaptor100.

In some embodiments, the cover200is made from a material that can generate desired amount of friction against the inner surface710of the vial190(for example, inner surface710shown inFIG.7A). The friction between the cover200and the inner surface710of the vial190can prevent or inhibit accidental distal translation of the piston150. In some embodiments, the cover200is a molded elastomer.

The body220of the piston150can include a head222, one or more sets of racks228, a stopper230, and a proximal portion240. The head222can include one or more flaps226and a distal end224. The head222can be positioned inside the cover200(for example, in a cavity500as shown inFIG.5A) when the head222is coupled with the cover200. The flaps226can each include a rear edge227that can abut against an inner surface of the cover200and prevent the cover200from slipping off of the head222. The distal end224can be shaped such that when the head222is inserted into the cavity500of the cover200, the tip204and its inner surface wraps about an outer surface of the distal end224(for example, as shown inFIG.5B). This can provide a desired seal between the cover200and the head222(for example, an inner surface of the distal end204and an outer surface of the distal end224) that can prevent or inhibit flow of, for example, fluid stored in the vial190into an area between the cover200and the head222during use.

The racks228can be formed on the body220. For example, the racks228can be formed along a longitudinal axis defined by the length of the body220(as shown inFIGS.5A and5B). The racks228can include teeth510that can engage corresponding arms (for example, arms610shown inFIGS.6A and6B) of the cap member110to restrict the movement of the piston150through the cap member110. The racks228and the corresponding arms (for example, the arms610) of the cap member110can be a locking mechanism that restricts the movement of the piston150through the cap member110.

The stopper230can extend radially outward from an outer circumference of the body220proximate to the proximal portion240. The stopper230can engage the proximal end216of the cap member110to prevent further movement (for example, distal translation) of the piston150with respect to the cap member110(for example, through the cap member110). Additionally, the stopper230can abut against an opening of a testing device (e.g., a cartridge for sensing and/or identifying pathogens, genomic materials, proteins, and/or other small molecules or biomarkers) or another storage device (for example, for fluid samples) during use such that fluid stored in the vial190can be transferred to the testing device or the other storage device via the vial adaptor100.

In some embodiments, the piston150can only translate distally (for example, towards the vial190) and cannot translate proximally (for example, away from the vial190). The movement of the piston150with respect to the cap member110is further described herein.

In some embodiments, the piston150and the cap member110may be integrated into a single device, while the piston150being able to move (for example, translate distally or proximally) with respect to the cap member110.

FIG.3illustrates a perspective view of the vial adaptor100. The cover200can include a distal aperture300formed on a distal end of the tip204. During use, as the piston150distally translates towards the vial190, the cover200and the distal aperture300can move, for example, into a cavity700(seeFIGS.7A-7C) of the vial190. As the cover200moves into the cavity (for example, the cavity700) of the vial190, it displaces the volume of the cavity and generates a positive pressure change in the vial190. Because of the seal between the cover200and the inner surface (for example, the inner surface710) of the vial190, the volume displacement generated by the distal movement of the piston150(and the cover200) can cause flow of fluid stored in the vial190via the distal aperture300and out of the vial190via the vial adaptor100. In some embodiments, at least a portion of the cover200and the distal aperture300extends into a portion of the vial190.

With references toFIGS.4A-SB, the cover200can be removably coupled with head222of the body220. The cover200can include the cavity500(seeFIGS.5A and5B) formed inside the tip204and the base202. The shape of the cavity500can correspond to the shape of the head222of the body220such that the head222can be inserted within the cavity500of the cover200without much clearance. This can prevent the head222from slipping away from the cover200or the cover200slipping off from the head222.

The cavity500can include a first portion550and a second portion560. The first portion550can be a space circumferentially surrounded by an inner surface of the base202. The first portion550can receive the flaps226of the head222. The second portion560can be a space circumferentially surrounded by an inner surface of the tip204. The second portion560can be narrower than the first portion550. As described herein, the second portion560can receive the distal end224of the head222.

The cover200can include a lip524that is circumferentially formed at a proximal end of the cover200and forming a proximal aperture520of the cover200. The lip524can extend inwards towards the center of the proximal aperture520from the body of the base202such that the end of the lip524defines the proximal aperture520. The proximal aperture520may be circular or some other desired shape. The lip524can include a tapered edge522that can facilitate and guide insertion of the head222into the cavity500of the cover200. Once the head222is inserted into the cavity500of the cover200, a distal edge526of the lip524(for example, an edge of the lip524that faces towards the vial190during use) can abut the rear edge227of the flaps226to prevent the head222from slipping out from the cover200.

The body220can include a distal opening502, a proximal opening504, and a channel506extending and formed between the distal opening502and the proximal opening504. When the cover200is placed on the head222of the body220, the distal opening502of the body220can substantially align with the distal aperture300of the cover200, as shown inFIG.5B. The gap between the cover200and the head222can be minimized to prevent any diverted flow into the gap between the cover200and the head222.

In some embodiments, the width of the channel506can stay the same or vary along the length of the piston150. For example, the width of the channel506can, as shown inFIGS.5A and5B, gradually increase from the distal opening502to the proximal opening504. In another example, the width of the channel can remain substantially the same between the majority of the channel506between the distal opening502and the stopper230, and increase significantly at the proximal end240. The gradual increase of the width of the channel506can facilitate flow through the channel506.

As described herein and shown inFIG.5A, the rack228can include teeth510. The teeth510can be triangular in shape. The teeth510can each include a leading edge512and a stopping edge514that can facilitate and restrict movement of the piston150through the cap member110, respectively.

FIGS.6A and6Billustrate various views of the cap member110of the vial adaptor100. The cap member110can include a proximal opening600, a distal opening602, an arm610, and the threaded portion620. The proximal opening600can be dimensioned to receive the piston150. The distal opening602can be dimensioned to, for example, extend over at least a portion of the vial190(for example, the threaded portion290of the vial190). The threaded portion620can be formed on an inner surface of the distal opening602and can couple with a corresponding threaded portion (for example, the threaded portion290) of the vial190. As described herein, the interaction between the threaded or interlocking portion620of cap member110and the threaded or interlocking portion290of the vial190can allow the cap member110of the vial adaptor100to removably couple with the vial190.

The arm610can include a first portion614and a second portion616. The first portion614can include a first end614A coupled to an inner circumference604of the proximal opening600and a second end614B at a predetermined distance away from the first end614A. As shown inFIG.6A, the first portion614can extend inwardly (for example, in a direction towards the center of the proximal opening600) from the inner circumference604of the proximal opening600between the first end614A and the second end614B. The second portion616can extend distally (for example, in a direction away from the proximal opening600and towards the distal opening602) from the second end614B of the first portion614. The second portion616can extend substantially orthogonally with respect to the first portion614. The second portion616can include a first end616A and a second end616B, where the first end616A is attached to the second end614B of the first portion614. The second end616B can be a free end and include a detent612formed about the second end616B of the second portion616. The detent612can a curved end that is curved inwards and extending away from the second portion616, for example, as shown inFIGS.6A and6B.

In some embodiments, the cap member110can include more than one of the arm610. For example, as shown inFIGS.6A and6B, the cap member110can include two arms610that are positioned on opposite sides of the inner circumference604. Alternatively, the two arms610can be positioned 90 degrees from one another or any other suitable angles. The detents612of the arms610can be curved towards each other.

FIGS.7A-7Cillustrate cross-sectional views of the vial adaptor100, showing different positions of the piston150during use.FIG.7Aillustrates relative position of the piston150of the vial adaptor100with respect to the vial190and the cap member110prior to actuation (for example, distal translation of the piston150towards the vial190) Prior to actuation, at least a portion of the piston150(for example, the cover200and the head222) may be positioned inside the vial190. Additionally, the outer circumference of the cover200of the piston150can abut against the inner surface of the vial190to provide water-tight seal between the inner surface of the vial190and the cover200. The water-tight seal can prevent or inhibit any flow of fluid stored in the vial190being diverted into a space between the cap member110and the body220of the piston150. In some embodiments, the detent612of the arms610of the cap member110can abut against a distal-most tooth610of the rack228prior to actuation of the piston150.

FIGS.7B and7Cillustrates relative position of the piston150with respect to the vial190and the cap member110during distal translation of the piston150. As described herein, the piston150(or the body220of the piston150) can be actuated or translated distally towards the vial190(for example, as indicated by a directional arrow A). When the piston150moves in the direction A, the cover200and the head222of the piston150moves further into the vial190. This causes a positive pressure change or volume displacement in the vial190, which causes a flow of fluid stored in the vial190out of the vial190via the distal aperture300of the cover200, the distal opening502, the channel506, and the proximal opening504(for example, as indicated by directional arrows B). Additionally, when the piston150moves in the direction A (for example, moving distally towards the vial190), the arm610of the cap member110can move along the rack228towards the stopper230by sliding long the leading edges512of the teeth510. The teeth510of the rack228can be shaped such that the arm610can move towards the stopper230(for example, by sliding along the leading edges512) but not towards the head220. When the piston150is pulled in a direction away from the vial190(for example, in a direction opposite of direction A as shown inFIG.7B), the stopping edge514of the teeth510of the rack228can engage the detent612of the arm610to prevent or inhibit movement of the piston150being pulled away from the vial190. This can prevent or inhibit negative volume displacement (that is, increase in the volume inside the vial190) and decrease in pressure in the vial190, which can lead to re-aspiration of, for example, fluid withdrawn from the vial190.

When the piston150is fully actuated (for example, at its distal-most position with respect to the cap member110), the stopper230of the piston150can abut against the proximal end216of the cap member. Additionally, the detent612of the arm610may or may not abut against a proximal-most tooth510of the rack228when the piston150is fully actuated.

With reference toFIGS.8A and8B, the vial adaptor100can be used to transfer, for example, fluid stored in the vial190to a receiving device800. The proximal portion240of the piston150can be inserted into an opening802of the receiving device800. To prevent accidental leak from the vial190via the vial adaptor100, the vial190and the vial adaptor100can be oriented to have the vial190positioned below the vial adaptor100while the proximal portion240is being coupled to the opening802of the receiving device800. In some embodiments, the proximal portion240and the opening802can be coupled via friction fit. In some embodiments, the proximal portion240and the opening802can have corresponding attachment features (for example, threads) that allow the proximal portion240and the opening802to be removably secured to each other.

Once the vial190and the vial adaptor100are coupled to the receiving device800, the receiving device800can be positioned below the vial190and the vial adaptor100. The piston150can then be translated towards the cap member110by, for example, pushing the vial190and the cap member110towards the receiving device800. Pushing the vial190and the cap member110towards the receiving device800can cause the cover200of the piston150to move towards or into the vial190to generate positive pressure or volume displacement in the vial190. The positive pressure or volume displacement in the vial190can cause flow of, for example, fluid stored in the vial190to the receiving device800.

FIG.9illustrates an example method900of transferring fluid from a vial (for example, the vial190) to a receiving device (for example, a testing device) using the vial adaptor100. At step902, a vial (for example, the vial190) is attached to the cap member110of the vial adaptor100. For example, as described herein, the vial can include a threaded portion that can be screwed into the threaded portion620of the cap member110. At step904, the distal end (for example, the cover200) of the piston150is inserted into the cap member110via the proximal opening600(seeFIG.6A). In some embodiments, the piston150is integrated with the cap member110while being able to, for example, translate distally towards the vial190, and as such, the step904may be optional.

At step906, an opening of a receiving device (for example, a testing device or a cartridge) is coupled to the proximal portion240of the piston150. In some embodiments, the opening of the device and the proximal portion240can have corresponding coupling features (for example, threads, snap-fit, or a single thread and lock coupling) that allow the piston150to be removably secured to the opening of the receiving device. In some embodiments, the proximal portion240of the piston150can be coupled to the opening of the receiving device via friction fit. At step908, the piston150is actuated. As described herein, the piston150may be actuated by distally translating towards the vial190. When the piston150moves towards the vial190, the movements of the cover200and the seal between the cover200and the inner surface of the vial190can generate positive pressure and volume displacement in the vial190, which can in turn generate flow out of the vial190and into the piston150. In some embodiments, in order to facilitate the flow out of the vial190, into the piston150, and into the receiving device, the vial190, the vial adaptor100, and the receiving device (for example, the cartridge800) may be positioned as shown inFIGS.8A and8B.

The term “comprising” as used herein is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. By “consisting of” is meant including, and limited to, whatever follows the phrase “consisting of.” Thus, the phrase “consisting of” indicates that the listed elements are required or mandatory, and that no other elements may be present. By “consisting essentially of” is meant including any elements listed after the phrase, and limited to other elements that do not interfere with or contribute to the activity or action specified in the disclosure for the listed elements. Thus, the phrase “consisting essentially of” indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present depending upon whether or not they materially affect the activity or action of the listed elements.