Patent Publication Number: US-2023143682-A1

Title: Apparatus and methods for controlling heating of an objective in a linescanning sequencing system to improve resolution

Description:
RELATED APPLICATION SECTION 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63/277,992, filed Nov. 10, 2021, and U.S. Provisional Patent Application No. 63/282,555, filed on Nov. 23, 2021, the content of each which is incorporated by reference herein in their entireties and for all purposes. 
    
    
     BACKGROUND 
     A linescan sequencing system may use laser line illumination to detect and sequence a biological specimen. The laser line illumination may be substantially in the shape of a line or a substantially line-shaped illumination. High power laser line illumination enables high throughput scanning using a time delay integration (TDI) sensor to detect fluorescence emissions from a flow cell. An optical imager for use with such an optical sequencing system includes a beam shaping group having one or more optical elements configured and arranged to form a line-shaped illumination beam and an objective configured and arranged to focus the line-shaped illumination beam at a flow cell to cause fluorescence emissions from the flow cell. 
     SUMMARY 
     Advantages of the prior art can be overcome and benefits as described later in this disclosure can be achieved through the provision of apparatus and methods for controlling heating of an objective in a linescanning sequencing system to improve resolution. Various implementations of the apparatus and methods are described below, and the apparatus and methods, including and excluding the additional implementations enumerated below, in any combination (provided these combinations are not inconsistent), may overcome these shortcomings and achieve the benefits described herein. 
     In accordance with a first implementation, an apparatus includes or comprises a beam source, a beam shaping group, and an objective. The beam source for providing input radiation and the beam shaping group including or comprising one or more optical elements positioned to receive the input radiation from the beam source, and to perform beam shaping on the input radiation to form a shaped beam. The objective positioned to receive the shaped beam and to transform the shaped beam into a probe beam. The objective further configured to provide the probe beam to a focal plane of the objective for optically probing a sample. The beam shaping group is configured to adjust one or more properties of the shaped beam over time to generally uniformly heat the objective over a region of incidence for the shaped beam. 
     In accordance with a second implementation, an apparatus for controlling thermal lensing or absorption based heating on an objective includes or comprises: a beam source to provide input radiation; a beam shaping group having or comprising: one or more optical elements configured to receive the input radiation from the beam source and further configured to shape the input radiation into a substantially line-shaped beam being substantially uniform along a long axis of the substantially line-shaped beam, and wherein the substantially line-shaped beam has or comprises a short axis perpendicular to the long axis, and a modifier configured to widen the first beam in a direction along the short axis of the substantially line-shaped beam; and an objective configured and positioned to transform the shaped beam into a probe beam focused to a focal plane of the objective, wherein the objective is defocused such that the focal plane is further from the objective than a sample being optically probed, wherein the modifier is configured to widen the first beam to generally uniformly illuminate the objective. 
     In accordance with a third implementation, an apparatus including or comprising a beam source, a multi-mode fiber, and a beam shaping group. The beam source configured to provide input radiation. The multi-mode fiber configured to receive the input radiation from the beam source and to output radiation from an output of the multi-mode fiber, the output being at an output plane of the multimode fiber. The beam shaping group having or comprising one or more optical elements configured to (i) receive the output radiation from the multi-mode fiber, (ii) project an image of the output plane of the multi-mode fiber, and (iii) expand the image in one direction. The objective configured to receive the image from the beam shaping group, and further configured to project the image to a focal plane of the objective. 
     In accordance with a fourth implementation, a method of controlling heating of an objective includes or comprises: providing, by a beam source, input radiation to a beam shaping group, the beam shaping group including or comprising one or more optical elements; performing, by the beam shaping group, beam shaping of the input radiation and forming a shaped beam; and focusing, by an objective, the shaped beam to form a probe beam, the probe beam focused at a focal plane of the objective for optically probing a sample. The beam shaping group adjusts one or more properties of the shaped beam over time to generally uniformly heat the objective. 
     In accordance with a fifth implementation, a method of controlling heating of an objective includes or comprises: providing, by a beam source, input radiation to a beam shaping group, the beam shaping group including or comprising one or more optical elements; shaping, by the beam shaping group, the input radiation into a substantially line-shaped beam being substantially uniform along a long axis of the substantially line-shaped beam, and wherein the substantially line-shape beam has or comprises a short axis perpendicular to the long axis; widening, by a modifier in the beam shaping group, the substantially line-shaped beam in a direction along the short axis of the substantially line-shaped beam to form a shaped beam; and transforming, by an objective, the shaped beam into a probe beam, the probe beam being focused to a focal plane of the objective. The objective is defocused such that the focal plane is further from the objective than a sample being optically probed and the modifier is configured to widen the substantially line-shaped beam to generally uniformly illuminate the objective. 
     In further accordance with the first, second, third, fourth, and/or fifth implementations, an apparatus and/or method may further include or comprise any one or more of the following: 
     In an implementation, the one or more optical elements are configured to form the first shaped beam as a substantially line-shaped beam and the beam shaping group further includes or comprises a modifier configured to change a beam offset for the substantially line-shaped beam over time, such that, at different times, the substantially line-shaped beam is made to be incident on the objective at different respective locations of the objective. 
     In another implementation, the modifier is configured to change the beam offset over time such that the probe beam is a substantially unchanged line-shaped beam at or near the focal plane of the objective at different beam offsets 
     In another implementation, the modifier is at least one of a selectively tiltable pane of material, a mirror, a wedge, or a prism. 
     In another implementation, the beam shaping group is further configured for the modifier to periodically cycle the beam offset through a plurality of beam offsets. 
     In another implementation, the modifier is configurable to move the substantially line-shaped beam back and forth across a transverse axis of the objective. 
     In another implementation, the modifier is configured to rotate the substantially line-shaped beam about an optical axis of the objective. 
     In another implementation, the beam offset may be in one or two directions. 
     In another implementation, the beam shaping group is configured to: perform beam shaping on the input radiation to form a substantially line-shaped beam as the shaped beam during a first time period; provide the substantially line-shaped beam to the objective during the first time period; perform beam shaping on the input radiation to form a broad beam as the shaped beam during a second different time period; and provide the broad beam to the objective during the second time period to pre-heat the objective. 
     In an implementation, the first time period corresponds to a time period of optical scanning of a sample, and the second time period corresponds to a time period when optical scanning of a sample is not being performed 
     In an implementation, the beam source is at least one of a laser, a laser diode, a diode-pumped solid-state laser, or a coherent light source. 
     In an implementation, the one or more optical elements includes or comprises a Powell lens having or comprising a Powell axis, and the modifier expands the first beam along a non-Powell axis, the non-Powell axis being perpendicular to the Powell axis. 
     In another implementation, the modifier includes or comprises at least one of a cylindrical lens, a cylindrical telescope, an excitation cylindrical telescope, a defocus lens, a prism array, or a diffuser. 
     In another implementation, the beam source is at least one of a laser, a laser diode, a diode-pumped solid-state laser, or a coherent light source. 
     In an implementation, the one or more optical elements includes or comprises at least one of a cylindrical microlens array, or a diffractive optical element. 
     In another implementation, the beam source is at least one of a laser, a laser diode, a diode-pumped solid-state laser, or a coherent light source. 
     In according with an implementation, the shaped beam includes or comprises a substantially line-shaped beam, and wherein the method further includes or comprises: changing, by a modifier included or comprised in the beam shaping group, a beam offset of the substantially line-shaped beam over time, such that, at different times, the substantially line-shaped beam is incident on the objective at different respective locations of the objective. 
     In accordance with another implementation, the modifier is configured to change the beam offset over time such that the probe beam is a substantially unchanged line-shaped beam at or near the focal plane of the objective at different beam offsets. 
     In accordance with another implementation, the modifier includes or comprises at least one of a selectively tiltable pane of material, a mirror, a wedge, or a prism. 
     In accordance with another implementation, the method further includes or comprises changing, by the beam shaping group, the beam offset by periodically cycling by controlling the modifier to periodically cycle the beam offset through a plurality of beam offsets. 
     In accordance with another implementation, the modifier is configurable to move the substantially line-shaped beam back and forth across a transverse axis of the objective. 
     In accordance with another implementation, the modifier is configurable to rotate the substantially line-shaped beam about an optical axis of the objective. 
     In accordance with another implementation, the beam offset may be in one or two directions. 
     In accordance with another implementation, the method further includes or comprises: performing, by the beam shaping group, beam shaping on the input radiation to form a substantially line-shaped beam as the shaped beam during a first time period; providing the substantially line-shaped beam to the objective during the first time period; performing, by the beam shaping group, beam shaping on the input radiation to form a broad beam as the shaped beam during a second different time period; and providing the broad beam to the objective during the second time period to pre-heat the objective. 
     In accordance with another implementation, the first time period corresponds to a time period of optical scanning of a sample, and wherein the second time period corresponds to a time period when optical scanning of a sample is not being performed. 
     In accordance with another implementation, the beam source is at least one of a laser, a laser diode, a diode-pumped solid-state laser, or a coherent light source. 
     In accordance with another implementation, the one or more optical elements includes or comprises a Powell lens having or comprising a Powell axis, and widening the substantially line-shaped beam includes or comprises expanding, by the modifier, the substantially line-shaped beam along a non-Powell axis, the non-Powell axis being perpendicular to the Powell axis. 
     In accordance with another implementation, the modifier includes or comprises at least one of a cylindrical lens, a cylindrical telescope, an excitation cylindrical telescope, a defocus lens, a prism array, or a diffuser. 
     In accordance with another implementation, the beam source is at least one of a laser, a laser diode, a diode-pumped solid-state laser, or a coherent light source. 
     In accordance with a sixth implementation, a method for controlling heating of an objective includes or comprises: providing, by a beam source, input radiation to a multi-mode fiber; guiding, by the multi-mode fiber, the input radiation and outputting the inputting radiation from an output of the multimode fiber, the output being at an output plane; expanding, by a beam shaping group, an image of the output plane of the multi-mode fiber in one direction of the image; projecting, by the beam shaping group, the image of the output plane of the multi-mode fiber onto an objective; and projecting, by the objective, the image from the beam shaping group to a focal plane of the objective. 
     In accordance with an implementation, the one or more optical elements includes or comprises at least one of a cylindrical microlens array, or a diffractive optical element. 
     In accordance with another implementation, the beam source is at least one of a laser, a laser diode, a diode-pumped solid-state laser, or a coherent light source. 
     It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein and/or may be combined to achieve the particular benefits of a particular aspect. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the subject matter disclosed herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, together with the detailed description below, are incorporated in and form part of the disclosure, and serve to further illustrate examples of concepts that include the claimed invention, and explain various principles and advantages of those examples. Moreover, the figures only show those specific details that are pertinent to understanding the examples of the disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
         FIG.  1    illustrates a schematic diagram of an example optical imager apparatus in accordance with the teachings of this disclosure and having a beam shaping group configured to control heating of an objective. 
         FIG.  2    shows an example pattern of illumination of a sample resulting from the optical imager apparatus of  FIG.  1    in accordance with teachings of this disclosure. 
         FIG.  3    shows an example pattern of illumination of an objective over time resulting from the optical imager apparatus of  FIG.  1    in accordance with teachings of this disclosure. 
         FIG.  4    illustrates a schematic diagram of another example optical imager apparatus in accordance with the teachings of this disclosure and having a beam shaping group configured to control heating of an objective. 
         FIG.  5    shows an example pattern of illumination of an objective resulting from the optical imager apparatus of  FIG.  4    in accordance with teachings of this disclosure. 
         FIG.  6 A  illustrates an example illumination pattern in the X-axis resulting from the optical imager apparatus of  FIG.  4    in accordance with teachings of this disclosure. 
         FIG.  6 B  shows an example illumination pattern in the Y-axis resulting from the optical imager apparatus of  FIG.  4    in accordance with teachings of this disclosure. 
         FIG.  7    illustrates a schematic diagram of yet another example optical imager apparatus in accordance with the teachings of this disclosure and having a beam shaping group configured to control heating of an objective. 
         FIG.  8 A  shows an example pattern of illumination of the objective resulting from the optical imager apparatus of  FIG.  7    using the multi-mode fiber, the expander, and rotationally symmetric collimator as the collimator. 
         FIGS.  8 B  shows an example pattern of illumination of the objective resulting from the optical imager apparatus of  FIG.  7    using the multi-mode fiber, the expander, and rotationally symmetric collimator as the collimator. 
         FIGS.  8 C  shows another example pattern of illumination of the objective resulting from the optical imager apparatus of  FIG.  7    using the multi-mode fiber, the expander, and rotationally symmetric collimator as the collimator. 
         FIG.  8 D  shows an example pattern of illumination at the objective resulting from the optical imager apparatus of  FIG.  7    using the multi-mode fiber, the expander, and an anamorphic collimator as the collimator. 
         FIG.  9    illustrates a schematic diagram of still another example optical imager apparatus in accordance with the teachings of this disclosure and having a beam shaping group configured to control heating of an objective. 
         FIG.  10    illustrates an example mask for the optical imager apparatus of  FIG.  9   . 
         FIG.  11    is a flowchart representative of example processes that may be performed to implement operations of the examples disclosed herein. 
         FIG.  12    illustrates a schematic diagram of an example implementation of a system in which teachings of this disclosure may be implemented. 
     
    
    
     The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
     DETAILED DESCRIPTION 
     Although the following description discloses a detailed description of implementations of methods, apparatuses and/or articles of manufacture, it should be understood that the legal scope of the property right is defined by the words of the claims set forth at the end of this patent. Accordingly, the following detailed description is to be construed as examples only and does not describe every possible implementation, as describing every possible implementation would be impractical, if not impossible. Numerous alternative implementations could be implemented, using either current technology or technology developed after the filing date of this patent. It is envisioned that such alternative implementations would still fall within the scope of the claims. 
     Use of a line-shaped illumination beam at a sample on a flow cell or another substrate in a linescan sequencing system typically entails passing a line-shaped beam through an objective of an optical imager of the sequencing system. When high power illumination is used, optical elements may absorb radiation causing absorption based heating and further may cause thermal lensing of the optical elements. For example, optical elements formed of materials with absorptions of 3%, 5%, 10%, or greater, absorb radiation during operation of the linescan sequencing system causing localized heating of the optical element which may result in astigmatic thermal lensing, anisotropic mechanical expansion, higher-order nonlinear optical contributions, or other distortions and undesirable effects. Additionally, the wavelength(s) of the illumination may further exacerbate localized heating of optical elements. Localized heating in a region of an optical element may cause a gradient in focusing power across optical elements such as the objective and cause uneven thermal expansions and refractive index changes resulting in astigmatism in the line-shaped beam, image quality degradations in linescan images, and/or any other degradations. The region of the optical element may include a center line of a lens, a center Gaussian region, etc. The optical degradations due to localized heating may not be easily correctable with further optical elements, in some instances. Additionally, adding further optical elements increases system costs, complexity of optical aligning and maintenance, and increases required space/real estate and weight of the system. 
     At least one aspect of this disclosure is directed toward an apparatus, in particular an optical imager, for use with a system that can be used to perform an analysis on one or more samples of interest. The sample may include one or more DNA clusters, such as a DNA cluster that has been linearized to form a single stranded DNA (sstDNA). In various examples, the apparatus is designed to reduce, manage, and/or control astigmatic thermal lensing of an objective of an optical imager apparatus of the system by generating a generally or substantially line-shaped illumination pattern at the sample in a manner that does not entail passing a substantially line-shaped beam through the objective or otherwise controls absorption based heating of the objective. By preventing and/or reducing non-uniform heating of an objective, the imaging resolution of a sequencing scanner that includes one of the example optical imager apparatuses disclosed herein can be increased. 
     A number of non-limiting example optical imager apparatuses are described below in connection with the figures. The beam transmitted through the objective may be changed over time using beam shifting, reshaping, or other methods to more uniformly heat the objective, in some examples. The beam passed through the objective may be broadened along a non-Powell axis such as along the smaller field angle axis or non-fanning axis of a Powell lens, thereby more uniformly illuminating the objective. The objective may then defocus the illumination beam to obtain a generally or substantially line-shaped illumination of the sample, in some examples. The beam may be broadened during pre-heating periods of time when the sample is not exposed to illumination and then narrowed to a line-shaped beam for illumination of a sample during sampling periods of time, in some examples. While examples are described herein as controlling heating of an objective, the present techniques may be used to control heating of other optical elements of an optical imager apparatus. 
     Reference will now be made in detail to non-limiting examples, some of which are illustrated in the accompanying drawings. 
     Controlling Heating Using Beam Decentering 
       FIG.  1    illustrates an example optical imager apparatus  100  in accordance with disclosed examples that may be part of a sequencing system such as a system  1200  of  FIG.  12   . The apparatus  100  is generally configured to form a generally or substantially line-shaped pattern of probe illumination  105  on a sample  110  on a flow cell or another substrate. As used herein, a “flow cell” can include a device having a lid extending over a reaction structure to form a flow channel therebetween that is in communication with a plurality of reaction sites of the reaction structure, and can include a detection device that detects designated reactions that occur at or proximate to the reaction sites. The shaped pattern of probe illumination  105  is a generally or substantially line-shaped pattern, in disclosed examples. Exposure to the probe illumination  105  causes the sample  110  to fluoresce and the emitted florescent illumination or radiation can be detected, sensed, and/or imaged by any number and/or types of scanners  115  having one or more detectors, sensors, or cameras. 
     The optical imager apparatus  100  includes an example beam shaping group  120  disposed along an optical axis A, with the shaping group  120  arranged and configured to receive an input beam  125  generated by a beam source  130 . The input beam  125  may be referred to herein as input radiation. The beam shaping group  120  further alters the input beam to form a desired shaped beam  135  having a desired spatial profile. The beam source  130  may be implemented using any number and/or type(s) of lasers, laser diodes, diode-pumped solid-state lasers, coherent light sources, light emitting diodes, black body sources, optical amplifiers, filters, and/or amplifier stages. The beam source  130  may, however, be implemented in different ways. 
     The beam source  130  may emit light in the blue region of visible light, in some examples. In other examples, the beam source  139  may emit light in the ultraviolet spectrum or another spectrum for exciting fluorescence from a probed sample. Further, while described often herein as a beam, the light or beam may additionally be referred to herein as radiation or illumination, as a person of ordinary skill in the art would recognize. For example, it may be more convenient to discuss the light in terms of a beam when describing different spatial modes of the light, or as radiation when describing heat loads or absorption depending on the context of the discussion. While described herein as being a single beam and a single beam source  130 , it should be understood that multiple beam sources may provide multiple beams individually, in a pulsed interleaved manner, or simultaneously to the elements of the systems and apparatus described herein. 
     A collimator (not shown for clarity of illustration) may be disposed along the optical axis A between the beam source  130  and the beam shaping group  120  to collimate the input beam  125  as needed or desired. One or more collimators, lenses, or telescopes may be used to manage the size of the beam as the beam propagates between beam shaping elements, between elements of the optical imager apparatus  100 , or to focus the beam at a focal (far field) plane, for example. 
     The beam shaping group  120  includes any number and/or type(s) of optical components or elements, such as focusing surfaces, lenses, reflective surfaces, or mirrors, diffractive elements, filters, polarizers, waveplates, apertures, spatial light modulators, and microlens arrays. One or more of the optical components or elements of the beam shaping group  120  may be disposed along the optical axis A and configured to shape the input beam  125  to form, generate, etc. the desired shaped beam  135  at a far field having the sample  110 , to allow for optical probing of the sample  110 . The beam shaping group  120  may include a Powell lens  140 , a beam shaping lens, and/or diffractive or scattering components. The substantially line-shaped beam profile  105  at the far field coincides with the profile of one or more line scanning sensors  115  allows for probing of the sample in flow cell applications. 
     An objective  145  is disposed along the optical axis A and the objective  145  focuses the shaped beam  135  such that the probe illumination  105  is propagated toward and focused on the sample  110 . The objective  145  has an objective pupil (not shown for clarity of illustration) and the objective is disposed to receive the shaped beam  135  such that the objective pupil is not overfilled, in some examples. That is, the shaped beam  135  is not clipped by the objective pupil or any other apertures in association with the objective  145 . 
     The objective  145  transforms the shaped beam  135  into the probe illumination  105 , with the probe illumination  105  having a substantially line-shaped beam profile at a focal plane of the objective  145 . The focal plane of the objective  105  may be at the sample  110  or a region of the sample  110 , in a region along the optical axis A upstream of the sample  110 , or in a region along the optical axis A downstream the sample  110  such as between the sample  110  and the scanner  115 . The probe illumination  105  may further be referred to herein as a probe beam in certain contexts. 
     A controller  150  of the optical imager apparatus  100  or, more generally of a scanning system including the optical imager apparatus  100 , is used to control and/or configure the beam shaping group  120  to perform the beam shaping and manage and/or control heating of the objective  145 . 
     The beam shaping group  120  includes one or more example modifiers (one of which is designated at reference numeral  155 ) that can be controlled and/or positioned to modify one or more characteristics of the shaped beam  135  to control, manage, uniformize, and/or distribute the shaped beam  135  and heating the objective  145 . The modifier  155  may be located at any number of locations in the beam shaping group  120  but, in some implementations, is disposed along the optical axis A follow downstream of the Powell lens  140 . The modifier  155  may modify the shaped beam  135  while the optical imager apparatus  100  is being operated for linescan imaging and, in some implementations, the modifier  155  may modify the shaped beam  135  in between linescan images being captured. The modifier  155  may modify the shaped beam  135  during periods of time when the scanner  115  is not capturing or imaging fluorescence from the sample  110 , for example. 
     The modifier  155  selectively changes the pattern of the shaped beam  135  over time such as by beam offsetting, while maintaining a consistent, substantially line-shaped pattern of probe illumination  105  at the sample  110  and/or at a focal plane of the objective  145 . The shaped beam  135  is substantially line-shaped, in some examples, and the modifier  155  decenters the shaped beam  135  by different amounts and/or directions over time such that the shaped beam  135  is incident at different locations on the objective  145 . The pattern of probe illumination  105  at the sample  110  will retain its desired line-shaped pattern and size and continue to fall incident at the same place on the sample  110  because the modifier  155  decenters the shaped beam  135  without modifying the angle at which the shaped beam  135  falls incident on the objective  145 . The shaped beam  135  may be offset in one or both directions on the objective  145  such as along the horizontal and vertical axes. 
     The modifier  155  can be selectively positioned, tilted, and/or controlled by the controller  150  and/or an associated instrument to sweep the shaped beam  135  back and forth across the objective  145  or to cycle the beam offset through a plurality of beam offsets in a set pattern or order, in some examples. The modifier  155  may include one or more of a selectively tiltable pane of material, a mirror, a one-dimensional wedge, a prism, a dispersive element, a polarizer, and/or a waveplate. The modifier  155  may include a tillable transparent plate that provides the beam displacement in a horizontal and/or vertical direction through optical refraction. The controller  150  and/or an associated instrument may cause the modifier  155  to rotate to orbit the line-shaped beam  135  about a central axis or optical axis of the objective  145  (i.e., a Z-axis), such as around the optical axis A of  FIG.  1   , in examples. The modifier  155  may include two prisms configured as a Risley prism pair for translating the shaped beam  135  around the objective  145 . One or more of the prisms of the Risley prism pair may be rotated or translated to provide a beam offset in a horizontal or vertical direction, or may rotate the position of the shaped beam  135  around the objective  145 . 
       FIG.  2    shows an example pattern of illumination  200  that may be provided as the probe illumination  105  provided to the sample  110  by the optical imager apparatus  100  as the modifier  155  decenters the beam  135  over time. The pattern of illumination  200  is a substantially line-shaped pattern of illumination  200  having a long axis P which may be along the Powell axis of a Powel lens, in examples regardless of any decentering of the beam  135  by the modifier  155 . The substantially line-shaped pattern further has a short axis S that is perpendicular to the long axis P. The substantially line-shaped pattern of illumination  200  as illustrated in  FIG.  2    has a peak intensity that spans along the long axis P, resulting in substantially uniform intensity along the long axis, while the intensity quickly decreases along the short axis S. 
       FIG.  3    shows an example pattern of illumination  300  of the objective  145  integrated over time with the shaped beam  135  provided to the objective  145  at three different positions on the objective  145 . The objective  145  may have a circular aperture or lens and, thus, for simplicity and clarity, the objective  145  is represented in  FIG.  3    by a circle. The modifier  155  provided the substantially linearly shaped beam  135  to the objective at a central position  302   C , and two decentered positions, a left position  302   L , and a right position  302   R . The example illumination  300  includes three different line-shaped patterns  305 ,  306  and  307  corresponding to the beam  135  being centered at a first time at the central position  302   C , decentered in a first direction to the right position  302   R  at a second time, and decentered in a second direction to the left position  302   L  at a third time, respectively. The resulting illumination  300  is substantially more uniform as shown than would result by providing the shaped beam  135  to the objective  145  at a single position (e.g., as shown in  FIG.  2   ). The illumination pattern  300  may result in significantly more uniform illumination and, thus, more uniform heating of the objective  145 , especially when the objective  145  heats slowly (e.g., over seconds) due to absorption of illumination. While illustrated as moving along the short axis S of the illumination  300 , the modifier may shift the beam offset in a vertical direction along the long axis P, or along a diagonal direction, or another direction for providing radiation to different parts of the objective  145  at different times. 
     Controlling Heating Using Non-Powell Axis Beam Widening According to an Example 
       FIG.  4    illustrates another example optical imager apparatus  400  in accordance with disclosed examples that may be part of a sequencing system such as the system  1200  of  FIG.  12   . The apparatus  400  is generally configured to provide a substantially line-shaped pattern of probe illumination  105  to a sample  110  on a flow cell, for example. The shaped pattern of the probe illumination  105  is a substantially line-shaped pattern, in disclosed examples. The probe illumination  105  is exposed to the sample  110  and causes the sample  110  to fluoresce and the scanner(s)  115  detects, senses, and/or images radiative emissions from the sample  110 . 
     Elements of  FIG.  4    that are substantially identical and/or functionally similar to elements of  FIG.  1    are designated with identical reference numerals in  FIGS.  1  and  4   . The description of these elements will not be repeated here for the sake of a compact disclosure. The interested reader is instead referred to the description of these elements provided above in connection with  FIG.  1   . The radiation and beams may additionally be provided between elements of  FIGS.  1  and  4    through free-space, optical fibers, another waveguide, or by another means capable of transmitting optical radiation. 
     The beam shaping group  120  of  FIG.  4    includes one or more example wideners (one of which is designated at reference numeral  405 ) that can be configured, adapted, controlled, and/or positioned to modify one or more characteristics of the shaped beam  135  to control, manage, and/or uniformize illumination of and, thus, heating of the objective  145 . The widener  405  may be located at any number of locations in the beam shaping group  120  but, in some implementations, the widener  405  is disposed along the optical axis A downstream of the Powell lens  140 . 
     The widener  405  widens the shaped beam  135  along the non-Powell axis such as the short axis S of  FIG.  2   . The widening of the beam  135  increases the area of the illumination field, thereby reducing the overall illuminance such as lumens per area and fluence such as energy per area provided to the objective  145 . Widening of the beam  135  increases the footprint of the illumination by the beam  135  on the objective  145  and causes a more uniform irradiation and/or heating of the objective  145 . A more correctable optical aberration may be achieved as a result that is more uniform or spherical, less intense, more gradual in gradient or differential. An example resultant illumination pattern  500  is shown in  FIG.  5   . Example wideners  405  include a cylindrical lens, a cylindrical telescope, an excitation cylindrical telescope, a defocus lens, a prism array, a diffuser, a birefringent element, a spatial light modulator, a microlens array, and/or a diffractive element positioned and configured to widen the shaped beam  135  along its non-Powell axis such as a non-substantially linear axis. An excitation cylindrical telescope is used, in some examples, to control the beam waist in the non-Powell axis. This method allows control of the peak beam intensity at both imaging and non-imaging points within the Z-space of the objective  145  such as along optical axis A in the direction of propagation shown in  FIG.  1   . This method can moreover be used to control the incident footprint of the shaped beam  135  at points internal to the objective  145 . As used herein, the term “footprint” is used to refer to the various radiation field, or illumination shape angles such as horizontal and vertical angles of a substantially linear or rectangular field, circular radius of a field, or geometric parameters and values associated with Gaussian or other shaped beams or fields. Further, the footprint is also indicative of energy distribution of the field, and therefore, radiative absorption and heat distribution of the objective  145 . 
     The widening of the pattern of the shaped beam  135  by the widener  405  increases the width of the line-shaped pattern of the probe illumination  105  incident on the sample  110  along the non-scan axis, parallel to the non-Powell axis). The objective  145  can be defocused to compensate for the increase in the width of the probe illumination  105  by moving the objective  145  along the Z-axis to focus the pattern  105  on a focal plane  605  beyond the surfaces of the sample  110 , as illustrated in  FIGS.  6 A and  6 B . The Z-axis of the objective  145  is along the propagation axis of the shaped beam  135 , which, in examples, is along the optical axis A of  FIGS.  1  and  4   .  FIG.  6 A  shows an example illumination pattern  610  in the X-axis, being the substantially linear or Powell axis, when the objective  145  is de-focused.  FIG.  6 B  shows an example illumination pattern  615  in the Y-axis, being the non-Powell axis, when the objective  145  is de-focused. The objective  145  may be defocused such that rays  620  in the Y-axis crossover at the sample  110 , as shown in  FIG.  6 B .  FIGS.  6 A and  6 B  illustrate that defocusing the objective  145  results in a substantially line-shaped pattern of illumination on the sample  110  while having the widened beam  135  incident on the objective  145  (e.g., as shown in  FIGS.  5  and  6 B ). 
     Controlling Heating Using Non-Powell Axis Beam Widening According to Another Example 
       FIG.  7    illustrates yet another example optical imager apparatus  700  in accordance with disclosed examples that may be part of a sequencing system such as the system  1200  of  FIG.  12   . The apparatus  700  is generally configured to form a generally line-shaped pattern of probe illumination  105  on a sample  110  on a flow cell or other substrate. The shaped pattern of probe illumination  105  is a generally line-shaped pattern, in disclosed examples. Fluorescent emissions by the sample  110  caused by the shaped pattern of probe illumination  105  can be detected, sensed, and/or imaged by the scanner(s)  115 . 
     Elements of  FIG.  7    that are substantially identical and/or functionally similar to elements of  FIG.  1    are designated with identical reference numerals in  FIGS.  1  and  7   . The description of these elements will not be repeated here for the sake of a compact disclosure. The interested reader is instead referred to the description of these elements provided above in connection with  FIG.  1   . 
     The beam shaping group  120  of  FIG.  7    includes a multi-mode fiber  705 , a collimator  708 , and an expander  710  that can be configured, adapted, controlled, and/or positioned to modify one or more characteristics of the shaped beam  135  to more spatially broadly or uniformly provide the shaped beam  135  to the objective  145  resulting in a more uniform heating of the objective  145 . A more correctable optical aberration may be achieved as a result that is more spherical, less relative deviation, and/or more uniform. The multi-mode fiber  705  may instead be a light pipe, multimode waveguide, or another radiation guiding material and/or structure. 
     The input beam  125  is input to the fiber  705  and the collimator  708  is disposed to receive the light from an output of the multi-mode fiber  705  and to collimate and provide the light to the bream shaping group  120 . The collimator  708  may be a rotationally symmetric collimator, or, in examples, the collimator  708  may be an anamorphic collimator that collimates a beam differently along different dimensions. 
     An anamorphic collimator may be used in any of the example systems described herein to further form a substantially line-shaped pattern, or for performing other beam shaping for controlling heating of the objective  145 . The beam shaping group  120  and the objective  145  are disposed at a position and configured to project a de-magnified image of an output end of the fiber  705  onto the sample  110  and positioned at an output plane. The multi-mode fiber  705  allows multiple spatial modes of propagation for radiation being guided in the fiber. Typical multi-mode fibers therefore provide larger overall optical fields with wider field angles as compared to single-mode fibers. The multi-mode fibers further allow broader bands of wavelengths to be guided through the fiber. Example expanders  710  include a cylindrical microlens array, a diffractive optical element, a telescope, and cylindrical telescope. The expander  710  is configured and positioned to widen the width of the beam  135  in the non-scan axis such as the non-Powell axis, and the objective  145  then projects the image onto the sample  110 . The beam source  130  may be selected to provide a wider input beam  125  to prevent or control asymmetry of the input beam  125  and, thus, asymmetry of the shaped beam  135 . 
       FIG.  8 A  shows an example pattern of illumination  800  of the objective  145  resulting from the optical imager apparatus  700  of  FIG.  7    using the multi-mode fiber  705 , the expander  710 , and rotationally symmetric collimator as the collimator  708 . The example illustrated in  FIG.  8 A  used a laser diode as the beam source  130 , a 200×200 μm multi-mode fiber as the fiber  705 , the beam shaping group  120  expanded the beam along the scan-axis, and a cylindrical microlens array as the expander  710  that expanded the beam along the non-scan axis to form the shaped beam  135 . The resultant pattern of illumination  800  is generally elongated along one axis such as, the vertical axis shown, to provide a wider footprint of illumination at the objective  135 , while preserving a focused tighter probe illumination  105  at, or near, the sample  110 . 
       FIGS.  8 B and  8 C  show example patterns of illumination  820  and  840  of the objective  145  resulting from the optical imager apparatus  700  of  FIG.  7    using the multi-mode fiber  705 , the expander  710 , and rotationally symmetric collimator as the collimator  708 . The examples illustrated in  FIGS.  8 B and  8 C  used a laser diode as the beam source  130 , a 100×100 μm multi-mode fiber as the fiber  705 , the beam shaping group  120  expanded the beam along the scan-axis, and a cylindrical microlens array was used as the expander  710  that expanded the beam along the non-scan axis to form the shaped beam  135 . The illumination  820  of  FIG.  8 B  is incident on the objective  145  with a spacing distance of 50 mm between the beam shaping group  120  and the objective  145 . The illumination  820  of  FIG.  8 B  exhibits no clipping of the illumination  820  by any of the optical elements of the beam shaping group  120 . The illumination  840  of  FIG.  8 C  is incident on the objective with a spacing distance of about 75 mm between the beam shaping group  120  and the objective  145 . The rectangular features, such as less curved beam profile edges, of the illumination  840  are indicative of clipping, which, for the example of FIG. are due to pupil overfill of the objective  145 . Therefore, the respective illuminations  820  and  840  of  FIGS.  8 B and  8 C  provide substantially even illumination to the objective allowing for more even distributions of heating of the objective with and without clipping of the beam. 
       FIG.  8 D  shows an example pattern of illumination  860  at the objective  145  resulting from the optical imager apparatus  700  of  FIG.  7    using the multi-mode fiber  705 , the expander  710 , and an anamorphic collimator as the collimator  708 . The anamorphic collimator collimates the beam to have a smaller beam profile in the vertical direction (as illustrated) and a wider collimated beam profile in the horizontal direction to shrink the image of the output of the fiber  705  to a 48 μm field of view at the sample, which, in the present example, is a desired field of view for an illumination footprint at the sample  110 . The example illustrated in  FIG.  8 D  used a laser diode as the beam source  130 , a 150×150 μm multi-mode fiber as the fiber  705 , the beam shaping group  120  expanded the beam along the scan-axis, and a cylindrical microlens array as the expander  710  that expanded the beam along the non-scan axis to form the shaped beam  135 . The shorter focal length of the collimator  708  in the vertical direction resulted in a smaller overall beam than in the examples of  FIGS.  8 B and  8 C . The resultant pattern of illumination  860  is generally elongated along one axis, to provide a wider footprint of illumination at the objective  135 , while preserving a focused tighter probe illumination  105  at, or near, the sample  110 . Specifically, the anamorphic collimator allows for a smaller beam in the vertical direction while maintaining the focal length in the horizontal direction which is beneficial to shrink an image of the output of the multi-mode fiber  705  into a smaller illumination footprint field of view, such as shrinking an image of the 150 mm multi-mode fiber into a 48 μm field of view. 
     Controlling Heating With Pre-Heating 
       FIG.  9    illustrates yet another example optical imager apparatus  900  in accordance with disclosed examples that may be part of a sequencing system such as the system  1200  of  FIG.  12   . The apparatus  900  is generally configured to form a substantially line-shaped pattern of probe illumination  105  on a sample  110  on a flow cell and/or another substrate. The shaped pattern of probe illumination  105  is a substantially line-shaped pattern, in disclosed examples. The scanner(s)  115  can detect, sense, and/or image fluorescent emissions by the sample  110  caused by the shaped pattern of probe illumination  105 . 
     Elements of  FIG.  9    that are substantially identical and/or functionally similar to elements of  FIG.  1    are designated with identical reference numerals in  FIGS.  1  and  9   . The description of these elements will not repeated here for the sake of a compact disclosure. The interested reader is instead referred to the description of these elements provided above in connection with  FIG.  1   . 
     The controller  150  and/or an associated instrument configures, adapts, controls, and/or positions the beam shaping group  120 , and elements therein to modify one or more characteristics of the shaped beam  135  to preheat the objective  145 . The beam shaping group  120  can be configured to selectively output a substantially line-shaped pattern as the shaped beam  135  or a broad pattern as the shaped beam  135  at different times. An example broad pattern is generally circular or rectangular, and sized to illuminate a large portion of the pupil of the objective  145 . The broad pattern may thus be used to generally and uniformly illuminate all of the objective  145 , or a substantial portion of the objective and cause a more uniform heating of the objective  145 . A more correctable optical aberration may be achieved as a result that is more spherical, more uniform, less intense, etc. As described above, the substantially line-shaped pattern  135  can be used when linescanning the sample  110 . 
     The broad pattern probe illumination  135  may be output and/or generated by, for example, controlling the beam shaping group  120  to bypass, remove from an optical path, and/or alter a configuration of one or more beam shaping optical elements such as the Powell lens  140 . The broad pattern probe illumination may further be generated by bypassing, remove from the optical path, or otherwise manipulating any of the examples described above for widening a line-shaped pattern. A mask  905  such as an optical path flip in may be used when the broad pattern  135  is generated to block a central portion of the broad pattern  135  generally corresponding to the line-shaped pattern. The mask  905  may further be applied by a spatial light modulator or other tunable mask or filter element. 
       FIG.  10    illustrates an example mask  1000  that includes a solid central portion  1005  that blocks radiation from the central region of the mask  1000 . The central portion  1005  corresponds spatially to a central portion of the objective  145 , with the central portion  1005  of the mask  1000  configured to block radiation from reaching the central portion of the objective  145  while the mask is active. Selective broadening of the shaped radiation  135  combined with selective blocking of the central portion of the broadened shaped radiation  135  allows for providing radiation to, and heating of, the objective  145  to achieve more uniform heat distribution during operation of the optical imager apparatus  900 . Alternating between generation of the broad pattern and the substantially line-shaped pattern can further result in a generally, on average, uniform illumination of the objective  145  and, thus, a generally uniform heating of the objective  145 . The broad pattern can be used to preheat the outer portion of the objective  145  prior to imaging the sample  110 , with the inner portion of the objective  145  being subsequently heated by the line-shaped pattern while linescanning samples  110 . 
     Method of Controlling Heating 
       FIG.  11    is a flowchart of an example process  1100  that may be implemented by an apparatus, in particular an optical imager apparatus such as the example optical imager apparatuses  100 ,  400 ,  700  and  900 , to analyze one or more samples of interest. The sample may include one or more DNA clusters, such as a DNA cluster that has been linearized to form a single stranded DNA (sstDNA). 
     An apparatus receives an input beam (e.g., the example input beam  125 ) (block  1105 ). One or more properties of a shaped beam (e.g., the shaped beam  135 ) for a first time period are selected (block  1110 ). Example properties include, for the example optical imager apparatus  100 , a beam decentering offset amount. Example properties include, for the optical imager apparatus  900 , whether a line-shaped beam or a broad beam is to be generated. A beam shaping group (e.g., the beam shaping group  120 ) is configured to generate, form, and/or output the shaped beam based on at least the selected properties (block  1115 ). 
     The shaped beam is transformed into a substantially line-shaped sampling beam (e.g., the example probe illumination  105 ) at a focal plane (e.g., at a sample  110 ) of an objective (e.g., the objective  145 ) at block  1120 . The apparatus optically probes a sample, using the substantially line-shaped sampling beam (block  1125 ). 
     The blocks  1110  and  1115  may be repeated to configure the generation of different shaped beams (e.g., with different beam offsets). Thus, blocks  1110  and  1115  may be periodically and/or aperiodically repeated to move a line-shaped patterned probe illumination  135  about the objective  145  to more uniformly illuminate and, thus, more uniformly heat the objective  145 . The beam offset may be changed, and/or varied on a slow periodic basis such as every second or two or may be varied a higher frequency dither of beam position. The beam offset may be varied in one or two directions, or in various directions along multiple axes. 
     The blocks  1110  and  1115  may be carried out at a first time to generate a broad beam  135  that is generated until a second time when a linescan is to be performed. Before the linescan, blocks  1110  and  1115  may then be repeated to configure generation of a line-shaped beam  135  before block  1120  is started. 
     Example System 
       FIG.  12    illustrates a schematic diagram of an implementation of a system  1200  in accordance with the teachings of this disclosure. The system  1200  can be used to perform an analysis on one or more samples of interest. The sample may include one or more DNA clusters that have been linearized to form a single stranded DNA (sstDNA). In the implementation shown, the system  1200  receives a reagent cartridge  1202  and includes, in part, a drive assembly  1204  and a controller  1206 . The system  1200  also includes, an imaging system  1212 , and a waste reservoir  1214 . In other implementations, the waste reservoir  1214  may be included with the reagent cartridge  1202 . The imaging system  1212  include any one or more of the optical imager apparatus&#39;  100 ,  400 ,  700 ,  900  of  FIGS.  1 ,  4 ,  7 , and  9    disclosed herein. The controller  1206  is electrically and/or communicatively coupled to the drive assembly  1204 , and the imaging system  1212  and causes the drive assembly  1204 , and/or the imaging system  1212  to perform various functions as disclosed herein. 
     The reagent cartridge  1202  carries the sample of interest that can be loaded into channels of a flow cell  1220 . The drive assembly  1204  interfaces with the reagent cartridge  1202  to flow one or more reagents (e.g., A, T, G, C nucleotides) through flow cell  1220  that interact with the sample. 
     In an implementation, a reversible terminator is attached to the reagent to allow a single nucleotide to be incorporated onto a growing DNA strand. In some such implementations, one or more of the nucleotides has a unique fluorescent label that emits a color when excited. The color (or absence thereof) is used to detect the corresponding nucleotide. In the implementation shown, the imaging system  1212  excites one or more of the identifiable labels (e.g., a fluorescent label) and thereafter obtains image data for the identifiable labels. The labels may be excited by incident light and/or a laser and the image data may include one or more colors emitted by the respective labels in response to the excitation. The image data (e.g., detection data) may be analyzed by the system  1200 . The imaging system  1212  may be a fluorescence spectrophotometer including an objective lens and/or a solid-state imaging device. The solid-state imaging device may include a charge coupled device (CCD) and/or a complementary metal oxide semiconductor (CMOS). 
     After the image data is obtained, the drive assembly  1204  interfaces with the reagent cartridge  1202  to flow another reaction component (e.g., a reagent) through the reagent cartridge  1202  that is thereafter received by the waste reservoir  1214  and/or otherwise exhausted by the reagent cartridge  1202 . The reaction component performs a flushing operation that chemically cleaves the fluorescent label and the reversible terminator from the sstDNA. The sstDNA is then ready for another cycle. 
     Referring now to the drive assembly  1204 , in the implementation shown, the drive assembly  124  includes a pump drive assembly  1222 , a valve drive assembly  1224 , and an actuator assembly  192 . The pump drive assembly  1222  interfaces with a pump  1226  to pump fluid through the reagent cartridge  1202  and/or the flow cell  1220  and the valve drive assembly  1224  interfaces with a valve  1228  to control the position of the valve  1228 . The interaction between the valve  1228  and the valve drive assembly  1224  selectively actuates the valve  1228  to control the flow of fluid through fluidic lines  1230  of the reagent cartridge  1202 . One or more of the fluidic lines  1230  fluidically couple one or more reagent reservoirs  1232  and the flow cell  1220 . One or more of the valves  1228  may be implemented by a valve manifold, a rotary valve, a pinch valve, a flat valve, a solenoid valve, a reed valve, a check valve, a piezo valve, etc. 
     Referring to the controller  1206 , in the implementation shown, the controller  1206  includes a user interface  1234 , a communication interface  1236 , one or more processors  1238 , and a memory  1240  storing instructions executable by the one or more processors  1238  to perform various functions including the disclosed implementations. The user interface  1234 , the communication interface  1236 , and the memory  1240  are electrically and/or communicatively coupled to the one or more processors  1238 . 
     In an implementation, the user interface  1234  receives input from a user and provides information to the user associated with the operation of the system  1200  and/or an analysis taking place. The user interface  1234  may include a touch screen, a display, a key board, a speaker(s), a mouse, a track ball, and/or a voice recognition system. The touch screen and/or the display may display a graphical user interface (GUI). 
     In an implementation, the communication interface  1236  enables communication between the system  1200  and a remote system(s) (e.g., computers) via a network(s). The network(s) may include an intranet, a local-area network (LAN), a wide-area network (WAN), the intranet, etc. Some of the communications provided to the remote system may be associated with analysis results, imaging data, etc. generated or otherwise obtained by the system  1200 . Some of the communications provided to the system  1200  may be associated with a fluidics analysis operation, patient records, and/or a protocol(s) to be executed by the system  1200 . 
     The one or more processors  1238  and/or the system  1200  may include one or more of a processor-based system(s) or a microprocessor-based system(s). In some implementations, the one or more processors  1238  and/or the system  1200  includes a reduced-instruction set computer(s) (RISC), an application specific integrated circuit(s) (ASICs), a field programmable gate array(s) (FPGAs), a field programmable logic device(s) (FPLD(s)), a logic circuit(s), and/or another logic-based device executing various functions including the ones described herein. 
     The memory  1240  can include one or more of a hard disk drive, a flash memory, a read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), a random-access memory (RAM), non-volatile RAM (NVRAM) memory, a compact disk (CD), a digital versatile disk (DVD), a cache, and/or any other storage device or storage disk in which information is stored for any duration (e.g., permanently, temporarily, for extended periods of time, for buffering, for caching). 
     Additional Considerations 
     The foregoing description is provided to enable a person skilled in the art to practice the various configurations described herein. While the subject technology has been particularly described with reference to the various figures and configurations, it should be understood that these are for illustration purposes only and should not be taken as limiting the scope of the subject technology. 
     As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one implementation” are not intended to be interpreted as excluding the existence of additional implementations that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, implementations “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional elements whether or not they have that property. Moreover, the terms “comprising,” including,” having,” or the like are interchangeably used herein. 
     The terms “substantially,” “approximately,” and “about” used throughout this Specification are used to describe and account for small fluctuations, such as due to variations in processing. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. 
     There may be many other ways to implement the subject technology. Various functions and elements described herein may be partitioned differently from those shown without departing from the scope of the subject technology. Various modifications to these implementations may be readily apparent to those skilled in the art, and generic principles defined herein may be applied to other implementations. Thus, many changes and modifications may be made to the subject technology, by one having ordinary skill in the art, without departing from the scope of the subject technology. For instance, different numbers of a given module or unit may be employed, a different type or types of a given module or unit may be employed, a given module or unit may be added, or a given module or unit may be omitted. 
     Underlined and/or italicized headings and subheadings are used for convenience only, do not limit the subject technology, and are not referred to in connection with the interpretation of the description of the subject technology. All structural and functional equivalents to the elements of the various implementations described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and intended to be encompassed by the subject technology. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the above description. 
     It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the subject matter disclosed herein.