Patent Publication Number: US-2023133241-A1

Title: Automated specimen processing systems and methods

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of filing date of U.S. Provisional Application No. 62/988,171, filed on Mar. 11, 2020, the disclosure of which is incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     Aspects of the present technology relate to automated systems and methods for handling objects, such as culture plates or dishes. 
     BACKGROUND 
     Biological samples such as body fluids (e.g., blood, urine, etc.) water samples, food samples, soil samples, etc. are frequently tested for the presence or absence of microorganisms (e.g., bacteria, fungi, etc.). Such tests typically require the samples to be combined with nutrient media to cultivate the growth of a sufficient amount of microorganisms in the sample to allow for reliable detection. Testing samples for evidence of microbial growth has historically been a manual process. Lab technicians will prepare culture plates, inoculate them with a sample, place the inoculated plates in an incubator, and periodically check the plates for the growth of colonies of bacteria. When there is evidence of microbial growth, a lab technician will manually pick a portion of a colony for further analysis. To prepare the picked colony for further analysis, the lab technician typically combines the picked colony with a solution to create a suspension for downstream testing. Such downstream testing is used to determine, for example, the type of microorganism and/or the antibiotic susceptibilities and resistances of the microorganisms. These process steps are also often done manually, requiring significant numbers of technicians to prepare such samples in large laboratories with high throughput. 
     As a result, automated specimen processing systems, such as Becton, Dickinson and Company&#39;s BD Kiestra™ Total Lab Automation (TLA) system, have been developed to enhance the efficiency of clinical microbiology laboratories. Presently, the BD Kiestra TLA system has several distinct modules, such as the SorterA (a module for media storage and distribution), the BarcodA (a module for barcoding culture plates), the InoqulA™+(a module for initial specimen processing and inoculation), the ReadA Compact (a module for specimen incubation and imaging), and the ErgonomicA (a workbench). All of these modules are linked together by the two-way ProceedA conveyor system. The number of these modules can be adapted to the requirements of a clinical laboratory to provide a complete lab automation solution. Additional examples of automated specimen processing systems are described in Susan M. Novak &amp; Elizabeth M. Marlowe,  Automation in the Clinical Microbiology Laboratory,  33 Clinics in Laboratory Medicine 567 (2013) and A. Croxatto et al.,  Laboratory Automation in Clinical Bacteriology: What System to Choose ?, 22 Clinical Microbiology and Infection 217 (2016), both of which are incorporated herein by reference. 
     Within these types of automated systems, two recurring operations for handling culture plates are stacking and de-stacking. For example, culture plates may be delivered to one or more output stacks and picked up manually by a lab technician for follow-up work. In the BD Kiestra TLA system, stackers and de-stackers can be found in the SorterA, the ReadA Compact, and the ErgonomicA modules. 
     In many automated specimen processing systems, pneumatic actuators are used for stacking and de-stacking. However, such systems require an air compressor, which can be expensive to purchase, run, and maintain. Furthermore, an air compressor capable of providing a sufficient quantity of compressed air to one or more automated specimen processing systems may be quite loud. Thus, a need exists for stackers and de-stackers that are capable of reliability stacking and de-stacking culture plates without the use of compressed air. 
     BRIEF SUMMARY 
     The present disclosure describes automated systems and methods for handling objects, such as culture plates or dishes. For example, in one embodiment, the present disclosure describes an automated stacker and de-stacker comprising a clamping mechanism, a lift pad, a pair of pins, and a cabinet. A stack of culture plates may be stored in the cabinet. During a stacking operation, the pair of pins may be raised to stop a culture plate traveling along a conveyor track. Once stopped, the culture plate may be raised above the conveyor track by the lift pad and clamped by the clamping mechanism. During a de-stacking operation, the clamping mechanism may be opened, and the culture plate may be lowered onto the conveyor track by the lift pad. Advantageously, in some embodiments, the automated stackers and de-stackers described herein may be implemented with one or more electric actuators, which may be cheaper to purchase, run, and maintain than pneumatic actuators. Furthermore, the one or more electric actuators may also produce less noise than pneumatic actuators. 
     One aspect of the present disclosure relates to an automated stacker and de-stacker comprising a lift pad, a clamping mechanism comprising two or more clamps, and one or more processers for controlling the lift pad and the clamping mechanism. The one or more processers are configured to control the lift pad and the clamping mechanism to stack a first culture plate by: raising the lift pad along with the first culture plate resting atop the lift pad until a top surface of a lid of the first culture plate touches or is proximate to a bottom surface of a base of a second culture plate at the bottom of a first stack of culture plates, opening the clamping mechanism, further raising the lift pad along with the first culture plate and the first stack of culture plates supported thereon, and closing the clamping mechanism such that the two or more clamps contact a base of the first culture plate. The one or more processers are also configured to control the lift pad and the clamping mechanism to de-stack a third culture plate by: raising the lift pad until a top surface of the lift pad touches or is proximate to a bottom surface of a base of the third culture plate, opening the clamping mechanism, lowering the lift pad along with the third culture plate and a second stack of culture plates supported thereon, closing the clamping mechanism such that the two or more clamps contact a base of a fourth culture plate within the second stack of culture plates and that is resting atop a lid of the third culture plate, and further lowering the lift pad to separate the third culture plate from the second stack of culture plates. 
     In some embodiments, a force applied to the first and fourth culture plates by the clamping mechanism after it closes is small enough to permit the first and fourth culture plates to slide downwards until the lid of the first culture plate and a lid of the fourth culture plate contacts the two or more clamps. In some embodiments, each of the two or more clamps of the clamping mechanism comprise two edges positioned at an angle between 80 and 160 degrees relative to each other, and wherein each of the edges contact the bases of the first and fourth culture plates at different contact points. 
     In some embodiments, the automated stacker and de-stacker is incorporated into an automated specimen processing system that also includes a conveyor system comprising a track configured to transport culture plates to and from the automated stacker and de-stacker. In such embodiments, the further lowering of the lift pad to separate the third culture plate from the second stack of culture plates comprises lowering the lift pad to a position beneath the track and consequently placing the third culture plate on the track. In some embodiments, the lift pad comprises a shield configured to stop other culture plates traveling along the track while the lift pad is raised above the track. 
     In some embodiments, the automated stacker and de-stacker is in cooperative communication with a stopping mechanism comprising one or more pins. In such embodiments, the one or more processers of the automated stacker and de-stacker are further configured to control the one or more pins for stacking the first culture plate by raising the one or more pins above the track to stop the first culture plate from continuing to travel along the track at a position above the lift pad. In such embodiments, the one or more processers of the automated stacker and de-stacker are further configured to control the one or more pins for de-stacking the third culture plate by lowering the one or more pins below the track to permit the third culture plate to travel along the track. In some embodiments, at least one motor is coupled to the one or more pins and the lift pad such that the one or more processors can control the one or more pins and the lift pad by controlling the at least one motor. In some embodiments, the one or more pins contact the base of the first culture plate, but not the lid of the first culture plate, when stopping the first culture plate from continuing to travel along the track. 
     In some embodiments, the automated stacker and de-stacker is in cooperative communication with a flipper stopper comprising at least one flipper having two or more edges separated by a bend. In such embodiments, the one or more processers of the automated stacker and de-stacker are further configured to control the flipper stopper for stacking the first culture plate by rotating the at least one flipper to stop the first culture plate as it travels along the track at a position above the lift pad. In such embodiments, the one or more processers of the automated stacker and de-stacker are further configured to control the flipper stopper for de-stacking the third culture plate by rotating the at least one flipper to permit the third culture plate to travel along the track. In some embodiments, the at least one flipper is rotated by a pair of actuators when the pair of actuators apply opposing forces to separate portions of the flipper. In some embodiments, the at least one flipper is rotated by a moving magnet actuator. In some embodiments, the at least one flipper is coupled to a shaft disposed in a slot defined in a housing or a guide structure. 
     Another aspect of the present disclosure relates to a method comprising: positioning a first culture plate beneath a stack of culture plates and above a lift pad, raising the lift pad along with the first culture plate resting atop the lift pad until a top surface of a lid of the first culture plate touches or is proximate to a bottom surface of a base of a second culture plate at the bottom of the stack of culture plates, opening the clamping mechanism, further raising the lift pad along with the first culture plate and the stack of culture plates supported thereon, and closing the clamping mechanism such that two or more clamps of the clamping mechanism contact a base of the first culture plate. 
     In some embodiments, a force applied to the first and fourth culture plates by the clamping mechanism after it closes is small enough to permit the first culture plate to slide downwards until the lid of the first culture plate contacts the two or more clamps. 
     In some embodiments, the method further comprises: raising the lift pad until a top surface of the lift pad touches or is proximate to a bottom surface of a base of a third culture plate, opening the clamping mechanism a second time, lowering the lift pad along with the third culture plate and a second stack of culture plates supported thereon, closing the clamping mechanism such that the two or more clamps contact a base of a fourth culture plate within the second stack of culture plates, wherein the fourth culture plate is resting atop a lid of the third culture plate, and further lowering the lift pad to separate the third culture plate from the second stack of culture plates. 
     Yet another aspect of the present disclosure relates to a method comprising: raising a lift pad until a top surface of the lift pad touches or is proximate to a bottom surface of a base of a first culture plate at the bottom of a stack of culture plates, opening a clamping mechanism, lowering the lift pad along with the first culture plate and the stack of culture plates supported thereon, closing the clamping mechanism such that the two or more clamps contact a base of a second culture plate within the stack of culture plates, wherein the second culture plate is resting atop a lid of the first culture plate, and further lowering the lift pad to separate the first culture plate from the stack of culture plates. 
     Yet another aspect of the present disclosure relates to a stopping mechanism comprising one or more pins and one or more processers for controlling the one or more pins, wherein the one or more processers are configured to raise the one or more pins above a track of a conveyor system to stop an object from continuing to travel along the track, and lower the one or more pins below the track to permit the object to travel along the track. 
     Yet another aspect of the present disclosure relates to a stopping mechanism comprising a platform hingedly engaged with a pin and one or more processers for controlling the platform, wherein the one or more processers are configured to rotate the platform about the pin in a first direction to stop an object from continuing to travel along a track of a conveyor system, and rotate the platform about the pin in a second direction opposite the first direction to permit the object to travel along the track. 
     Yet another aspect of the present disclosure relates to a stopping mechanism comprising at least one flipper having two or more edges separated by a bend and one or more processers for controlling the at least one flipper, wherein the one or more processers are configured to rotate the at least one flipper in a first direction to stop an object from continuing to travel along a track of a conveyor system, and rotate the at least one flipper in a second direction opposite the first direction to permit the object to travel along the track. 
     Yet another aspect of the present disclosure relates to a transfer mechanism comprising an arm having a first end and a second end, a pivot joint positioned at the first end of the arm, a post positioned at the second end of the arm, and one or more processers for controlling the arm, wherein the one or more processers are configured to rotate the arm about the pivot joint in a first direction to stop, with the post, an object from continuing to travel along a first track of a conveyor system, and rotate the arm about the pivot joint in a second direction opposite the first direction to push, with the post, the object from the first track to a second track of the conveyor system. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIGS.  1 ( a ) and  1 ( b )  illustrate two different modules that may be integrated into an automated specimen processing system. 
         FIGS.  2 ( a )- 2 ( g )  illustrate a conveyor system that may be integrated into an automated specimen processing system. More specifically,  FIGS.  2 ( a )- 2 ( c )  illustrate different side-views of the conveyor system.  FIG.  2 ( d )  illustrates a top-view of the conveyor system.  FIGS.  2 ( e )- 2 ( g )  illustrate different cross-sections of the conveyor system. 
         FIGS.  3 ( a ) and  3 ( b )  illustrate a side-view and a cross-section, respectively, of a cabinet for storing a stack of culture plates and an automated stacker and de-stacker that may be integrated into an automated specimen processing system. 
         FIG.  4    illustrates how a clamping mechanism of the automated stacker and de-stacker of  FIG.  3 ( b )  may be configured to contact a culture plate within a stack of culture plates. 
         FIGS.  5 ( a ) and  5 ( b )  illustrate different top-views of a clamping mechanism of the automated stacker and de-stacker of  FIG.  3 ( b ) . 
         FIGS.  6 ( a ) and  6 ( b )  illustrate how the clamping mechanism of the automated stacker and de-stacker of  FIG.  3 ( b )  may be configured to support a stack of culture plates. 
         FIG.  7    is a photograph of a rim of a culture plate. 
         FIGS.  8 ( a ) and  8 ( b )  illustrate a side-view and a top-view, respectively, of how a pin of the automated stacker and de-stacker of  FIG.  3 ( b )  may be configured to contact a culture plate on a conveyor track. 
         FIG.  9    illustrates a side-view of the automated stacker and de-stacker of  FIG.  3 ( b ) . 
         FIG.  10    illustrates a side-view of the automated stacker and de-stacker of  FIG.  3 ( b ) . 
         FIGS.  11 ( a )- 11 ( f )  illustrate an automated stacker and de-stacker that may be integrated into an automated specimen processing system. More specifically,  FIG.  11 ( a )  illustrates a side-view of the automated stacker and de-stacker.  FIG.  11 ( b )  illustrates a side-view of a lift mechanism of the automated stacker and de-stacker.  FIG.  11 ( c )  illustrates a side-view of a clamping mechanism of the automated stacker and de-stacker.  FIG.  11 ( d )  illustrates a side-view of a linear actuator of the automated stacker and de-stacker.  FIG.  11 ( e )  illustrates a side-view of a pair of pins of the automated stacker and de-stacker.  FIG.  11 ( f )  illustrates a cross-section of the automated stacker and de-stacker when the lift mechanism is raised. 
         FIG.  12    illustrates a schematic of the control circuitry of an automated stacker and de-stacker that may be integrated into an automated specimen processing system. 
         FIG.  13    illustrates a method for stacking that may be performed by an automated stacker and de-stacker that may be integrated into an automated specimen processing system. 
         FIGS.  14 ( a )- 14 ( h )  illustrate different potential states of an automated stacker and de-stacker that has been integrated into an automated specimen processing system. 
         FIG.  15    illustrates a method for de-stacking that may be performed by an automated stacker and de-stacker that may be integrated into an automated specimen processing system. 
         FIGS.  16 ( a )- 16 ( h )  illustrate different potential states of an automated stacker and de-stacker that has been integrated into an automated specimen processing system. 
         FIGS.  17 ( a )- 17 ( k )  illustrate an automated stacker and de-stacker that may be integrated into an automated specimen processing system. More specifically,  FIG.  11 ( a )  illustrates a side-view of the automated stacker and de-stacker integrated with a conveyor system.  FIG.  11 ( b )  illustrates a side-view of the automated stacker and de-stacker.  FIGS.  17 ( c ) and  17 ( d )  illustrate different side views of a clamping mechanism of the automated stacker and de-stacker. FIGS.  17 ( e ) and  17 ( f ) illustrate different side views of a lift mechanism of the automated stacker and de-stacker.  FIGS.  17 ( g ) and  17 ( h )  illustrate different side views of a pair of pins of the automated stacker and de-stacker.  FIGS.  17 ( i )- 17 ( k )  illustrate different potential states of the lift mechanism and the pair of pins of the automated stacker and de-stacker. 
         FIGS.  18 ( a )- 18 ( q )  illustrate different stopping mechanisms that may be integrated into an automated specimen processing system. More specifically,  FIGS.  18 ( a )- 18 ( d ) and  18 ( e )  illustrate a first stopping mechanism.  FIG.  18 ( a )  illustrates a side view of the first stopping mechanism.  FIG.  18 ( b )  illustrates a top view of the first stopping mechanism.  FIGS.  18 ( c ) and  18 ( e )  illustrate different cross-sections of the first stopping mechanism.  FIGS.  18 ( d ) and  18 ( f )  illustrate different cross-sections of a second stopping mechanism.  FIGS.  18 ( g ) and  18 ( h )  illustrate different cross-sections of a third stopping mechanism.  FIGS.  18 ( i ) and  18 ( j )  illustrate different cross-sections of a fourth stopping mechanism.  FIGS.  18 ( k ) and  18 ( l )  illustrate different cross-sections of a fifth stopping mechanism.  FIGS.  18 ( m ) and  18 ( n )  illustrate different cross-sections of a sixth stopping mechanism.  FIG.  18 ( o )  illustrates a cross-section of a seventh stopping mechanism.  FIG.  18 ( p )  illustrates a cross-section of an eighth stopping mechanism.  FIG.  18 ( q )  illustrates a top view of a ninth stopping mechanism. 
         FIG.  19 ( a )- 19 ( e )  illustrate a stopping mechanism that may be integrated into an automated specimen processing system. More specifically,  FIGS.  19 ( a )- 19 ( d )  illustrate different cross-sections of the stopping mechanism.  FIG.  19 ( e )  illustrates a top view of the stopping mechanism. 
         FIGS.  20 ( a ) and  20 ( b )  illustrates a top view and cross-section, respectively, of a stopping mechanism that may be integrated into an automated specimen processing system. 
         FIG.  21    illustrates a flipper stopper that may be integrated into an automated specimen processing system. 
         FIGS.  22 ( a )- 22 ( c )  illustrate different side views of a flipper stopper that may be integrated into an automated specimen processing system. In  FIGS.  22 ( b ) and  22 ( c ) , a portion of a housing of the flipper stopper has been removed. 
         FIGS.  23 ( a )- 23 ( c )  illustrate a flipper stopper that may be integrated into an automated specimen processing system. More specifically,  FIG.  23 ( a )  illustrates a side-view of the flipper stopper integrated with a conveyor system.  FIG.  23 ( b )  illustrates a side-view of the flipper stopper without a portion of a housing of the flipper stopper.  FIG.  23 ( c )  illustrates a side-view of the flipper stopper without the housing. 
         FIG.  24    illustrates a clamping mechanism that may be integrated into an automated stacker and de-stacker. 
         FIG.  25    illustrates an automated specimen processing system with a gate stopper and a plurality of automated stackers and de-stackers. 
         FIGS.  26 ( a ) and  26 ( b )  illustrate a side-view and a cross-section, respectively, of a cabinet for storing a stack of culture plates and an automated stacker and de-stacker that may be integrated into an automated specimen processing system. 
         FIG.  27    illustrates a conveyor system that may be integrated into an automated specimen processing system. 
         FIGS.  28 ( a )- 28 ( f )  illustrate different modules that may be integrated into an automated specimen processing system. More specifically,  FIG.  28 ( a )  illustrates a two-way highway module.  FIG.  28 ( b )  illustrates the two-way highway module of  FIG.  28 ( a )  with an automated output stacker.  FIG.  28 ( c )  illustrates the two-way highway module of  FIG.  28 ( a )  with an automated stacker and de-stacker.  FIG.  28 ( d )  illustrates a one-way highway module.  FIG.  28 ( e )  illustrates a 90-degree turn module, a T-intersection module, and a 180-degree turn module.  FIG.  28 ( f )  illustrates a shortcut module. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are described in detail with reference to the figures wherein like reference numerals identify similar or identical elements. Many of the figures are drawn to scale. In such instances, measurements are provided in millimeters. However, it is to be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. 
       FIG.  1 ( a )  illustrates a module  100 A that may be integrated into an automated specimen processing system (e.g., the BD Kiestra TLA system). As shown, module  100 A includes a conveyor system  110 A and cabinets  120 A and  130 A. Cabinets  120 A and  130 A may each contain a stack of culture plates. Furthermore, automated stackers and de-stackers may be positioned beneath cabinets  120 A and  130 A under the stacks of culture plates. In other embodiments, the number of cabinets and/or automated stackers and de-stackers may be varied. For example, as shown in  FIG.  1 ( b ) , a module  100 B may include four separate cabinets for housing stacks of culture plates. Moreover, separate stackers and de-stackers may be positioned beneath each of these cabinets. As shown, module  100 B includes a conveyor system  110 B and cabinets  120 B,  130 B,  140 B, and  150 B. In some embodiments, an automated specimen processing system may include multiple modules (e.g., module  100 A or  100 B). For example, in some embodiments, module  100 A and  100 B may be positioned adjacently such that culture plates may exit module  100 A and immediately enter module  100 B. 
       FIGS.  2 ( a )- 2 ( g )  illustrate various views of a conveyor system  200  that may, for example, be integrated into modules  100 A and  100 B of  FIGS.  1 ( a )- 1 ( b ) . More specifically,  FIGS.  2 ( a )- 2 ( c )  illustrate three-dimensional renderings of conveyor system  200  and  FIGS.  2 ( d )- 2 ( g )  are scaled drawings that include measurements in millimeters. In other embodiments, the dimensions of conveyor system  200  may be modified. As shown, conveyor system  200  includes top cover  202 , bottom cover  204 , stage  206 , main track  210 , side track  220 , beam  232 , beam  234 , beam  236 , stopping mechanism  242 , stopping mechanism  244 , stopping mechanism  246 , off-ramp catcher  252 , on-ramp catcher  254 , scanner  262 , and scanner drive  264 . Main track  210  includes belt  212  and  214 . Side track  220  includes belt  222  and  224 . In some of  FIGS.  2 ( a )- 2 ( g ) , top cover  202  and/or bottom cover  204  are not illustrated so that other aspects of conveyor system  200  can be seen more clearly. 
     During operation, culture plates may traverse stage  206  along main track  210  and/or side track  220 . Culture plates may enter and exit conveyor system  200  on main track  210 . As a culture plate travels along main track  210 , it may be stopped by stopping mechanisms  242 ,  244 , and/or  246 . Furthermore, as a culture plate enters conveyor system  200 , it may be rotated by scanner drive  264  such that a barcode on the culture plate faces scanner  262 . Scanner  262  may then scan the barcode. The barcode information may be used by an automated specimen processing system to track the positions of the culture plates that are being processed. After a culture plate has been scanned, it may be transferred to side track  220  by off-ramp catcher  252 . Furthermore, after the culture plate has traveled the length of side track  220 , it may be transferred back to the main track  210  by on-ramp catcher  254 . In some embodiments, main track  210  and side track  220  are separately controlled. 
     In some embodiments, one or more automated stackers and de-stackers may be placed along side track  220 . In some embodiments, portions of the one or more automated stackers may extend through beams  234  and  236 . An example of an automated stacker and de-stacker that may be integrated with conveyor system  200  is illustrated in  FIGS.  3 ( a )- 3 ( b ) . As shown, automated stacker and de-stacker  300  includes clamping mechanism  310 , motor  322 , bi-directional lead screw  324 , motor  332 , and lift pad  334 . Clamping mechanism  310  includes clamps  312  and  314 . A cabinet  302  may be positioned above and supported by automated stacker and de-stacker  300 . A stack of culture plates  304  positioned within cabinet  302  may also be supported by automated stacker and de-stacker  300 . When automated stacker and de-stacker  300  is integrated with conveyor system  200 , a culture plate  306  may pass through automated stacker and de-stacker  300  as it travels along side track  220  atop belts  222  and  224 . 
     During operation, clamps  312  and  314  of clamping mechanism  310  may hold the culture plate at the bottom of the stack of culture plates  304 . Clamping mechanism may be opened and closed by motor  322 . More specifically, motor  322  may rotate bi-directional lead screw  324 , which is connected to clamps  312  and  314 . As shown in  FIG.  3 ( b ) , the entire stack of culture plates  304  may be held above side track  320  so that another culture plate (e.g., culture plate  306 ) may travel underneath the stack of culture plates  304  without contacting them. Additional culture plates may be raised and added to the stack of culture plates  304  by lift pad  334 . Similarly, culture plates may be lowered and removed from the stack of culture plates  304  by lift pad  334 . Lift pad  334  is raised and lowered by motor  332 . In some embodiments, motor  332  is connected to lift pad  334  via a lead screw. In some embodiments, motors  322  and  332  are electric motors (e.g., AC motors, DC motors, stepper motors, etc.). 
       FIG.  4    illustrates how a clamp (e.g., clamp  312  or  314 ) of clamping mechanism  310  may be configured to contact a culture plate within a stack of culture plates. As shown, culture plate  410  includes lid  412  and base  414 . Similarly, culture plate  420  includes lid  422  and base  424 . In this embodiment, a clamp of clamping mechanism  310  is configured to contact base  414  of culture plate  410  (not lid  412 ). If lid  412  was clamped (instead of base  414 ), base  414  would fall back down onto track  220 . In this embodiment, the thickness of the portion of the clamp of clamping mechanism  310  contacting culture plate  410  is 0.5 mm. Furthermore, in this embodiment, the clamp of clamping mechanism  310  contacts base  414  at a height of 18 mm relative to the bottom of culture plate  420 . However, the clamp of clamping mechanism  310  could be configured to contact base  414  at any height between 16.8 mm and 21.4 mm relative to the bottom of culture plate  420 . Nonetheless, by selecting a value in the middle of that range, there is a higher tolerance for error. In other embodiments, different dimensions may be used. 
       FIGS.  5 ( a )- 5 ( b )  illustrate top-views of clamping mechanism  310 . As shown in  FIG.  5 ( a ) , a clamp (e.g., clamp  312  or  314 ) of clamping mechanism  310  may be configured to contact a culture plate  510  at two different points. In this embodiment, culture plate  510  has a diameter of 85 mm and the two different contact points are 42.5 mm apart. However, in other embodiments, different dimensions may be used. In this embodiment, the two edges of the clamp of clamping mechanism  310  contacting culture plate  510  are positioned at an angle of 120 degrees relative to each other. However, in other embodiments, this angle may be increased in order to increase the distance between the two points at which the clamp of clamping mechanism  310  contacts culture plate  510 . Furthermore, in other embodiments, this angle may be decreased in order to increase the useable actuation distance of clamping mechanism  310 . Thus, in other embodiments, the angle between the two edges of the clamp of clamping mechanism  310  may, for example, be anywhere between 80 and 160 degrees. As shown in the embodiment of  FIG.  5 ( b ) , clamping mechanism  310  may be opened such that a culture plate  520  having a diameter of 96 mm or less can be released. In other embodiments, different dimensions may be used. 
       FIGS.  6 ( a )- 6 ( b )  illustrate how clamping mechanism  310  may be configured to support a stack of culture plates. As shown, the stack of culture plates includes culture plates  610  and  620 . Culture plate  610  includes lid  612  and base  614 . Similarly, culture plate  620  includes lid  622  and base  624 . As shown in  FIG.  6 ( a ) , the clamping force applied by clamping mechanism  310  to culture plate  620  is sufficient to hold the weight of the entire stack of culture plates. Alternatively, as shown in  FIG.  6 ( b ) , the clamping force applied by clamping mechanism to culture plate  620  is only sufficient to hold the weight of base  624 . In this situation, the stack of culture plates is permitted to slide downwards until lid  622  contacts clamps  312  and  314  of clamping mechanism  310 . To illustrate the advantages of such a configuration, assume that the stack consists of 50 culture plates and has a total weight of 2310 grams. Further, assume that the coefficient of friction between the culture plates and clamps  312  and  314  is 0.3. Under these parameters, the clamping force applied in  FIG.  6 ( a )  is 75.5 newtons and the clamping force applied in  FIG.  6 ( b )  is only 1.5 newtons. Therefore, in the configuration of  FIG.  6 ( b ) , base  624  is under significantly less stress than it is in the configuration of  FIG.  6 ( a ) . 
       FIGS.  8 ( a )- 8 ( b )  illustrate a side-view and top-view, respectively, of automated stacker and de-stacker  300 , wherein automated stacker and de-stacker  300  includes pins  842  and  844 . As shown, pins  842  and  844  may be raised to stop a culture plate  810  as it travels along side track  220  atop belts  222  and  224 . Pins  842  and  844  may also be lowered to permit culture plate  810  to pass. In some embodiments, pins  842  and  844  may be coupled to lift  334  such that lift  334  and pins  842  and  844  can be raised and lowered by the same mechanism (e.g., motor  332 ). As shown in this embodiment, pins  842  and  844  have a height of 10 mm and a diameter of 6 mm. Furthermore, pins  842  and  844  are spaced apart by 80 mm. However, in other embodiments, different dimensions may be used. 
     As shown in  FIG.  8 ( a ) , pins  842  and  844  are configured to contact a base  814  (not a lid  812 ) of a culture plate  810 . Advantageously, this configuration minimizes the distance pins  842  and  844  need to be raised and lowered. In embodiments where the space underneath side track  220  is scarce, this is particularly important. However, pins  842  and  844  should still be raised to a sufficient height above side track  220  (e.g., 4 mm) that prevents culture plate  810  from jumping over pins  842  and  844 . Similarly, pins  842  and  844  should be lowered to a sufficient height below side track  220  that allows culture plate  810  to pass over pins  842  and  844  (e.g., 2.5 mm). For example, in some instances, a portion of a rim of base  814  may extend below belts  222  and  224 . This may occur when a gap in the rim of base  814  aligns with belt  222  or  224 . An example of a culture plate having a rim with a gap is illustrated in  FIG.  7   . As shown, a culture plate  710  includes lid  712  and base  714 . Base  714  includes rim  716 , which has a gap  718 . 
       FIG.  9    illustrates a side-view of automated stacker and de-stacker  300 . As shown, conveyor system  200  further includes side cover  908 , which is positioned above bottom cover  204 . Furthermore, lift pad  334  has been lowered to a position that is 2.5 mm below the surface of stage  206 . Much like pins  842  and  844 , lift pad  334  has been lowered to a position below the surface of stage  206  to ensure that a culture plate (e.g., culture plate  910 ) traveling along side track  220  can pass over lift pad  334 . During stacking and/or de-stacking processes, lift pad  334  may be raised to a position above clamps  312  and  314  of clamping mechanism  310 . For example, in some embodiments, lift pad  334  may be raised to a position where a top surface of lift pad  334  is flush with a top surface of side cover  908 . Therefore, in this embodiment, lift pad  334  may be raised 44.5 mm (i.e., 2.5 mm plus 42 mm). 
       FIG.  10    illustrates a side-view of automated stacker and de-stacker  300 . As shown, the clamping force of clamping mechanism  310  is provided by a spring  1016 . Clamping mechanism  310  is opened by rotating bi-directional lead screw  324  using motor  322 . As bi-directional lead screw  324  is rotated in a first direction (e.g., clockwise or counterclockwise), lead nuts  1026  and  1028  move away from clamps  312  and  314 , respectively. As bi-directional lead screw  324  is rotated in a second opposite direction (e.g., clockwise or counterclockwise), lead nuts  1026  and  1028  move towards clamps  312  and  314 , respectively. When lead nuts  1026  and  1028  contact and push against clamps  312  and  314 , respectively, clamping mechanism  310  starts to open. 
     In some embodiments, spring  1016  may provide a sufficient clamping force to center a culture plate during a de-stacking process. As shown, the stack of culture plates  304  positioned within cabinet  302  includes culture plate  1010 . Culture plate  1010  is positioned at the bottom of the stack of culture plates  304  and it is being held by clamping mechanism  310 . Furthermore, culture plate  1010  is held in a position such that clamp  312  is 2 mm away from lead nut  1026  and clamp  314  is 7 mm away from lead nut  1028 . Thus, culture plate  1010  is not centered above side track  220 , which includes belts  222  and  224 . In such a situation, as bi-directional lead screw  324  is rotated in a second direction and lead nuts  1026  and  1028  move towards clamps  312  and  314 , respectively, lead nut  1026  will contact clamp  312  before lead nut  1028  contacts clamp  314 . When this occurs, spring  1016  may be configured to provide a sufficient clamping force to pull clamp  314  towards lead nut  1028  as (a) lead nut  1026  pushes against clamp  312  and (b) lead nut  1028  continues to move towards clamp  314 . In such embodiments, spring  1016  may provide a clamping force that is greater than or equal to the force required to overcome the friction between the stack of culture plates  304  and lift pad  334 , allowing culture plate  1010  to slide laterally underneath the stack of culture plates. 
       FIGS.  11 ( a )- 11 ( f )  illustrate various side-views and/or components of an automated stacker and de-stacker  1100 . As shown in  FIG.  11 ( a ) , much like automated stacker and de-stacker  300  discussed above, automated stacker and de-stacker  1100  includes clamping mechanism  1110 , spring  1116 , motor  1122 , bi-directional lead screw  1124 , motor  1132 , lift pad  1134 , pin  1142 , and pin  1144 . Clamping mechanism  1110  includes clamps  1112  and  1114 . Lift pad  1134  includes shield  1136 . As shown, automated stacker and de-stacker  1100  is mounted to top plate  1101 . In some embodiments, top plate  1101  may form part of a stage of a conveyor system (e.g., stage  206  of conveyor system  200  of  FIGS.  2 ( a )- 2 ( g ) ). As shown, portions of clamp  1112 , clamp  1114 , lift pad  1134 , pin  1142 , and pin  1144  may extend through top plate  1101 . In some embodiments, motors  1122  and  1132  are electric motors (e.g., AC motors, DC motors, stepper motors, etc.). 
     As shown in  FIG.  11 ( b ) , motor  1132  is connected to lift pad  1134  via lead screw  1124 . Furthermore, a linear guideway  1150  is coupled to lift pad  1134 . Linear guideway  1150  includes rail  1152  and bearing block  1154 . Lift pad  1134  is coupled to rail  1152 , which can slide upwards and downwards through bearing block  1154 . Bearing block  1154  may be coupled to another stationary component of automated stacker and de-stacker  1100  (e.g., top plate  1101 ) and/or a conveyor system (e.g., stage  206  of conveyor system  200  of  FIGS.  2 ( a )- 2 ( g ) ). During operation, motor  1132  may rotate lead screw  1138  clockwise or counterclockwise in order to raise or lower lift pad  1134 . As lift pad  1134  is raised and lowered by motor  1132 , linear guideway  1150  provides stability to lift pad  1134 . 
     As shown in  FIG.  11 ( c ) , spring  1116 , bi-directional lead screw  1124 , and linear guideway  1160  extend from clamp  1112  to clamp  1114 . Linear guideway  1160  includes rail  1162  and bearing blocks  1164  and  1166 . Clamps  1112  and  1114  are coupled to bearing blocks  1164  and  1166 , respectively, both of which can slide along rail  1162 . As shown in  FIG.  11 ( d ) , lead nuts  1126  and  1128  are positioned on bi-directional lead screw  1124 . When automated stacker and de-stacker  1100  is assembled, lead nuts  1126  and  1128  are positioned on bi-directional lead screw  1124  between clamps  1112  and  1114 . 
     During operation, motor  1122  may rotate bi-directional lead screw  1124  clockwise or counterclockwise in order to open or close clamping mechanism  1110 . For example, in order to open clamping mechanism  1110 , motor  1122  may rotate bi-directional lead screw  1124  such that lead nuts  1126  and  1128  move towards clamps  1112  and  1114 , respectively. When lead nuts  1126  and  1128  contact and push against clamps  1112  and  1114 , respectively, they may exert a force that is greater than and opposes a clamping force (e.g., 23 newtons) of spring  1116 . When this happens, clamping mechanism starts to open. During this process, linear guideway  1160  provides stability to clamps  1112  and  1114 . Similarly, in order to close clamping mechanism  1110 , motor  1122  may rotate bi-directional lead screw  1124  such that lead nuts  1126  and  1128  move away from clamps  1112  and  1114 , respectively. When lead nuts  1126  and  1128  are no longer contacting clamps  1112  and  1114 , respectively, clamping mechanism  1110  is closed. 
     Advantageously, clamping mechanism  1110  does not require any electricity to stay in a closed position because the clamping force is provided by spring  1116 . Electricity is used in this embodiment to open clamping mechanism  1110 . Therefore, in the event of a power outage, a stack of culture plates will remain clamped and secured in automated stacker and de-stacker  1100 . Furthermore, by using spring  1116 , clamping mechanism  1110  can easily adapt to culture plates with different diameters. 
     As shown in  FIG.  11 ( e ) , pins  1142  and  1144  are urged upward by springs  1146  and  1148 , respectively. Furthermore, pin  1142  is coupled to pin  1144  via crossbar  1145 . Springs  1146  and  1148  are positioned beneath crossbar  1145 . During operation, lift pad  1134  may be used to lower pins  1142  and  1144 . For example, lift pad  1134  may be lowered by motor  1132  to a position where a portion of lift pad  1134  contacts crossbar  1145  and pushes springs  1146  and  1148  into a retracted state. Therefore, motor  1132  can advantageously be used to actuate lift pad  1134  and pins  1142  and  1144 . However, in other embodiments, multiple motors can be used to actuate these components. In some embodiments, the portion of lift pad  1134  that contacts crossbar  1145  is a notch that can be adjusted with two or more screws. In some embodiments, pins  1142  and  1144  are guided by a pair of sleeve bearings with flanges. In some embodiments, pins  1142  and  1144  are configured to contact a base (not a lid) of a culture plate. In other embodiments, pins  1142  and  1144  are configured to contact a lid of a culture plate. In some embodiments, springs  1146  and  1148  may be configured to raise pins  1142  and  1144  by 6.5 mm to a position that is 4 mm above top plate  1101 . In some embodiments, springs  1146  and  1148  are conical compression springs, which, advantageously, can be fully flattened when compressed and minimize the space required by automated stacker and de-stacker  1100 . 
     As shown in  FIG.  11 ( f ) , cabinet  1102  may be positioned above and supported by automated stacker and de-stacker  1100 . A stack of culture plates  1104  positioned within cabinet  1102  may also be supported by automated stacker and de-stacker  1100 . As shown, lift pad  1134  is raised to a position where it is touching culture plate  1105 , which is at the bottom of the stack of culture plates  1104 . Furthermore, shield  1136  of lift pad  1134  is preventing another culture plate  1106  traveling towards automated stacker and de-stacker  1100  from accidentally getting caught underneath lift pad  1134 . 
       FIG.  12    illustrates a schematic of the control circuitry of an automated stacker and de-stacker (e.g., automated stacker and de-stacker  300  or  1100 ). In this schematic, lines with arrows generally indicate a flow of data, and lines without arrows are power supply connections. In this embodiment, control circuitry  1200  includes controllers  1271 ,  1272 , and  1273 . Controllers  1272  and  1273  control motors  1222  and  1232 , respectively. In some embodiments, controllers  1272  and  1273  may be dedicated motor controllers. As shown, controller  1272  receives data from an optical sensor  1276  having a sensor module  1275  (e.g., SICK&#39;s WLL170-2P132 Fiber Optic Sensor) and a sensor cable  1277  (e.g., SICK&#39;s LL3-DB01 Fiber Optic Sensor Cable). In other embodiments, optical sensor  1276  may not include a sensor cable (e.g., SICK&#39;s VTE6-P3121S01 Photoelectric Proximity Sensor). Similarly, controller  1273  receives data from an optical sensor  1278  (e.g., Panasonic&#39;s PM-Y45 Photoelectric Sensor). Sensors  1276  and  1278  may transmit, for example, infrared or visible light. Power supply  1274  provides power to controllers  1272  and  1273 , which then provide power to sensors  1276  and  1278 , respectively. In some embodiments, control circuitry  1200  may include multiple power supplies. 
     Sensor  1276  may be used to determine whether a culture plate is ready to be stacked. For example, if control circuitry  1200  is used to control automated stacker and de-stacker  1100 , sensor  1276  may be used to determine whether a culture plate is positioned beneath clamping mechanism  1110 . In some such embodiments, sensor cable  1277  may be mounted to top plate  1101  and sensor module  1275  may be mounted elsewhere. During operation, sensor module  1275  sends light through sensor cable  1277 . When an object, such as a culture plate, is above sensor cable  1277 , the light initially sent by sensor module  1275  is reflected back to it through sensor cable  1277 . When this occurs, sensor  1276  may send controller  1272  a signal through a wire indicating that a culture plate is positioned above it. In some embodiments, the detection distance of sensor  1276  can be adjusted using a dial on sensor module  1275 . 
     Sensor  1278  may be used to determine whether a lift pad is in a particular position. For example, if control circuitry  1200  is used to control automated stacker and de-stacker  1100 , sensor  1278  may be used to determine whether lift pad  1134  is in a starting position. In some embodiments, while in a starting position, lift pad  1134  may be positioned beneath top plate  1101  and holding pins  1142  and  1144  in a retracted position. In some embodiments, sensor  1278  is a U-shaped optical sensor. In some such embodiments, sensor  1278  sends a signal to controller  1272  through a wire when an object breaks a beam of light between the two sides of the U-shape of sensor  1278 . Advantageously, this type of sensor can be highly accurate, compact, and inexpensive, and it does not exert any additional force on the components of automated stacker and de-stacker  1100 . 
     In some embodiments, controllers  1272  and/or  1273  may be used to detect whether motor  1222  and/or  1232  has stalled. For example, if control circuitry  1200  is used to control automated stacker and de-stacker  1100 , a stall detection process may be used to determine whether clamping mechanism  1110  is in a particular position. For example, motor  1222  will stall when clamping mechanism  1110  is in a fully extended open position. In such a position, clamps  1112  and  1114  are pushed against portions of the openings in top plate  1101  through which clamps  1112  and  114  extend. When this occurs, controller  1273  will detect that motor  1222  has stalled and, consequently, that clamping mechanism  1110  is in a fully extended open position. Advantageously, this type of detection process does not require an additional sensor. 
     However, in some embodiments, control circuitry  1200  may include additional sensors. For example, if control circuitry  1200  is used to control automated stacker and de-stacker  1100 , additional sensors may be used to determine (a) whether cabinet  1102  is full, (b) whether cabinet  1102  is empty, (c) whether a culture plate is in a stacking position where it can be added to the stake of plate  1104  in cabinet  1102 , (d) the position of clamping mechanism  1110 , (e) the position of lift pad  1134 , and/or (f) the position of pins  1142  and  1144 . Furthermore, in some embodiments, sensors  1276  and/or  1278  may be replaced with different types of sensors. For example, sensors  1276  and/or  1278  may be replaced with one or more ultrasonic sensors, inductive sensors, and/or capacitive sensors. 
     As shown in  FIG.  12   , communication between controllers  1272  and  1273  is handled by three data lines. Two wires connect outputs on controller  1272  to inputs on controller  1273 . If control circuitry  1200  is used to control automated stacker and de-stacker  1100 , these wires may carry a signal that tells controller  1273  to either open or close clamping mechanism  1110 . Furthermore, another wire may carry a feedback signal from an output on controller  1273  to an input on controller  1272 . If control circuitry  1200  is used to control automated stacker and de-stacker  1100 , that wire may carry a signal that tells controller  1272  whether clamping mechanism  1110  is open or closed. As shown, communication between controllers  1271  and  1272  is handled by a single data line. If control circuitry  1200  is used to control automated stacker and de-stacker  1100 , this data line may carry a signal from controller  1271  to controller  1272  that tells controller  1272  to either stack or de-stack a culture plate. 
     In some embodiments, controllers  1271 ,  1272 , and/or  1273  may communicate through any one of the following types of communication interfaces or standards: USB, Ethernet, RS-232, Serial Peripheral Interface (“SPI”), Inter-Integrated Circuit (“I2C”), Controller Area Network (“CAN”), or a custom-defined communications interface. Controllers  1271 ,  1272 , and/or  1273  may communicate may also communicate wirelessly through, for example, WiFi, Bluetooth, ZigBee, or a custom-defined wireless communications protocol. Similarly, numerous communication interfaces or standards can be utilized between controllers  1272  and  1273  and sensors  1276  and  1278 , respectively. 
     Those skilled in the art will appreciate that various modifications can be made to control circuitry  1200  of  FIG.  12   . For example, in some embodiments, control circuitry  1200  may include an additional data line for carrying a signal from controller  1271  to controller  1273  that tells controller  1273  to either stack or de-stack a culture plate. As another example, in some embodiments, the roles of controllers  1272  and  1273  may be reversed. For example, controller  1273  may receive commands from controller  1271  and send commands to controller  1272 . As another example, in some embodiments, controllers  1272  and  1273  may not directly communicate. Instead, controllers  1272  and  1273  may receive commands from controller  1271  and send data to controller  1271 . As yet another example, in some embodiments, controllers  1271 ,  1272 , and/or  1273  may be combined as a single integrated controller. 
       FIG.  13    illustrates a method  1300  for stacking that may be performed by an automated stacker and de-stacker (e.g., automated stacker and de-stacker  300  or  1100 ). It is to be understood that the arrows in  FIG.  13    are meant to illustrate one possible order in which the various processes of the method  1300  may be performed. However, in some embodiments, the blocks illustrated in  FIG.  13    may be rearranged. Moreover, in some embodiments, one or more blocks may be added and/or removed.  FIGS.  14 ( a )- 14 ( h )  illustrate an automated stacker and de-stacker  1400  in an automated specimen processing system that is performing an embodiment of method  1300 . In some embodiments, automated stacker and de-stacker  1400  may be structured and/or operated in much the same way as automated stackers and de-stackers  300  and/or  1100 . 
     In block  1310 , an automated stacker and de-stacker (e.g., automated stacker and de-stacker  1400 ) is initialized such that a lift pad (e.g., lift pad  1434 ) and pins (e.g., pins  1442  and  1444 ) are positioned below a conveyor track (e.g., side track  1420 ). An embodiment of block  1310  is illustrated in  FIG.  14 ( a ) . 
     In block  1320 , the pins (e.g., pins  1442  and  1444 ) are raised to a sufficient height above the conveyor track (e.g., side track  1420 ) to stop an incoming culture plate (e.g., culture plate  1406 ). In some embodiments, this may also involve raising the lift pad (e.g., lift pad  1434 ). For example, as explained above with reference to automated stacker and de-stacker  1100  of  FIGS.  11 ( a )- 11 ( f ) , motor  1132  ( FIG.  11 ( e )  controls lift pad  1434  and pins  1142  and  1144 . An embodiment of block  1320  is illustrated in  FIG.  14 ( b ) . As shown, pins  1442  and  1444  extend above side track  1420 , and a top surface of lift pad  1434  is positioned immediately below side track  1420 . 
     In block  1330 , the incoming culture plate (e.g., culture plate  1406 ) is stopped by the raised pins (e.g., pins  1442  and  1444 ) at a position that is both directly beneath a stack of culture plates (e.g., stack of culture plates  1404 ) and directly above the lift pad (e.g., lift pad  1434 ). An embodiment of block  1330  is illustrated in  FIG.  14 ( c ) . 
     In block  1340 , the culture plate (e.g., culture plate  1406 ) is raised by the lift pad (e.g., lift pad  1434 ) to a position where a top surface of a lid of the culture plate touches or is proximate to a bottom surface of a base of a culture plate at the bottom of the stack of culture plates (e.g., stack of culture plates  1404 ). In embodiments where the culture plate is merely raised to a position proximate to the stack of culture plates, there is a small gap therebetween. After a clamping mechanism (e.g., clamping mechanism  1410 ) is opened, the stack of culture plates may fall the short distance of the gap. However, after the stack of culture plates touches the top surface of the lid of the culture plate, the culture plate can support the stack of culture plates. An embodiment of block  1340  is illustrated in  FIG.  14 ( d ) . 
     In block  1350 , the clamping mechanism (e.g., clamping mechanism  1410 ) is opened and the culture plate (e.g., culture plate  1406 ) is raised along with the entirety of the stack of culture plates (e.g., stack of culture plates  1404 ) by the lift pad. In this block, the culture plate may be raised to a position where the clamps (e.g., clamps  1412  and  1414 ) of the clamping mechanism will contact the culture plate when the clamping mechanism is closed again. An embodiment of block  1350  is illustrated in  FIG.  14 ( e ) . 
     In block  1360 , the clamping mechanism (e.g., clamping mechanism  1410 ) is closed. As shown in  FIG.  14 ( f ) , the clamps (e.g., clamps  1412  and  1414 ) of clamping mechanism  1410  contact culture plate  1406  when clamping mechanism  1410  is closed. More specifically, the clamps contact a base of culture plate  1406 . As discussed above in relation to  FIGS.  6 ( a )- 6 ( b ) , the clamping force applied to culture plate  1406  by clamping mechanism  1410  can be minimized in this type of configuration. However, other configurations may be used. 
     In block  1370 , the lift pad (e.g., lift pad  1434 ) is lowered to a position below the conveyor track (e.g., side track  1420 ). An embodiment of block  1370  is illustrated in  FIG.  14 ( g ) . In some embodiments, the lift pad may be lowered to a similar position that it was in during block  1320 . For example, in  FIGS.  14 ( b ) and  14 ( g ) , lift pad  1434  is in a similar position. 
     In block  1380 , the pins (e.g., pins  1442  and  1444 ) are lowered to a position below the conveyor track (e.g., side track  1420 ). In some embodiments, this may also involve lowering the lift pad (e.g., lift pad  1434 ). For example, as explained above with reference to automated stacker and de-stacker  1100  of  FIGS.  11 ( a )- 11 ( f ) , motor  1132  controls lift pad  1134  and pins  1142  and  1144 . An embodiment of block  1380  is illustrated in  FIG.  14 ( h ) . 
       FIG.  15    illustrates a method  1500  for de-stacking that may be performed by an automated stacker and de-stacker (e.g., automated stacker and de-stacker  300  or  1100 ). It is to be understood that the arrows in  FIG.  15    are meant to illustrate one possible order in which the various processes of the method  1500  may be performed. However, in some embodiments, the blocks illustrated in  FIG.  15    may be rearranged. Moreover, in some embodiments, one or more blocks may be added and/or removed.  FIGS.  16 ( a )- 16 ( h )  illustrate an automated stacker and de-stacker  1600  in an automated specimen processing system that is performing an embodiment of method  1500 . In some embodiments, automated stacker and de-stacker  1600  may be structured and/or operated in much the same way as automated stackers and de-stackers  300  and/or  1100 . 
     In block  1510 , an automated stacker and de-stacker (e.g., automated stacker and de-stacker  1600 ) is initialized such that a lift pad (e.g., lift pad  1634 ) and pins (e.g., pins  1642  and  1644 ) are positioned below a conveyor track (e.g., side track  1620 ). An embodiment, of block  1510  is illustrated in  FIG.  16 ( a ) . 
     In block  1520 , the pins (e.g., pins  1642  and  1644 ) are raised to a position above the conveyor track (e.g., side track  1620 ). In some embodiments, this may also involve raising the lift pad (e.g., lift pad  1634 ). For example, as explained above with reference to automated stacker and de-stacker  1100  of  FIGS.  11 ( a )- 11 ( f ) , motor  1132  controls lift pad  1134  and pins  1142  and  1144 . An embodiment of block  1520  is illustrated in  FIG.  16 ( b ) . As shown, pins  1642  and  1644  extend above side track  1620 , and a top surface of lift pad  1634  is positioned immediately below side track  1620 . 
     In block  1530 , the lift pad (e.g., lift pad  1634 ) is raised to a position where a top surface of the lift pad touches or is proximate to a bottom surface of a base of a first culture plate (e.g., culture plate  1606 ) at the bottom of the stack of culture plates (e.g., stack of culture plates  1604 ). In embodiments where the lift pad is merely raised to a position proximate to the stack of culture plates, there is a small gap therebetween. After a clamping mechanism (e.g., clamping mechanism  1610 ) is opened, the stack of culture plates may fall the short distance of the gap. However, after the stack of culture plates touches the top surface of the lift pad, the lift pad can support the stack of culture plates. An embodiment, of block  1530  is illustrated in  FIG.  16 ( c ) . 
     In block  1540 , the clamping mechanism (e.g., clamping mechanism  1610 ) is opened and the first culture plate (e.g., culture plate  1606 ) is lowered along with the entirety of the stack of culture plates (e.g., stack of culture plates  1604 ) by the lift pad. In this block, a second culture plate (e.g., culture plate  1607 ) resting atop a lid of the first culture plate may be lowered to a position where the clamps (e.g., clamps  1612  and  1614 ) of the clamping mechanism will contact the second culture plate when the clamping mechanism is closed again. An embodiment, of block  1540  is illustrated in  FIG.  16 ( d ) . 
     In block  1550 , the clamping mechanism (e.g., clamping mechanism  1410 ) is closed. As shown in  FIG.  16 ( e ) , the clamps (e.g., clamps  1612  and  1614 ) of clamping mechanism  1610  contact culture plate  1607  when clamping mechanism  1610  is closed. More specifically, the clamps contact a base of culture plate  1607 . As discussed above in relation to  FIGS.  6 ( a )- 6 ( b ) , the clamping force applied to culture plate  1607  by clamping mechanism  1610  can be minimized in this type of configuration. However, other configurations may be used. 
     In block  1560 , the lift pad (e.g., lift pad  1634 ) is lowered to a position below the conveyor track (e.g., side track  1620 ). An embodiment, of block  1560  is illustrated in  FIG.  16 ( f ) . In some embodiments, the lift pad may be lowered to a similar position that it was in during block  1520 . For example, in  FIGS.  16 ( b ) and  16 ( f ) , lift pad  1634  is in a similar position. 
     In block  1570 , the pins (e.g., pins  1642  and  1644 ) are lowered to a position below the conveyor track (e.g., side track  1620 ). In some embodiments, this may also involve lowering the lift pad (e.g., lift pad  1634 ). For example, as explained above with reference to automated stacker and de-stacker  1100  of  FIGS.  11 ( a )- 11 ( f ) , motor  1132  controls lift pad  1134  and pins  1142  and  1144 . An embodiment, of block  1570  is illustrated in  FIG.  16 ( g ) . 
     In block  1580 , the first culture plate (e.g., culture plate  1606 ) is transported to another location within the automated specimen processing system by the conveyor track (e.g., side track  1620 ). An embodiment, of block  1580  is illustrated in  FIG.  16 ( h ) . 
       FIGS.  17 ( a )- 17 ( k )  illustrate various side-views and/or components of another automated stacker and de-stacker. As shown, automated stacker and de-stacker  1700  includes clamping mechanism  1710 , motor  1722 , motor  1732 , lift pad  1734 , pin  1742 , pin  1744 , controller  1772 , controller  1773 , sensor  1776 , sensor  1777 , sensor  1778 , and sensor  1779 . Clamping mechanism  1710  includes clamps  1712  and  1714 . Controller  1772  controls motor  1732 , which is used to raise and lower lift pad  1734 , pin  1742 , and pin  1744 . Controller  1773  controls motor  1722 , which is used to open and close clamping mechanism  1710 . In some embodiments, motors  1722  and  1732  are electric motors (e.g., AC motors, DC motors, stepper motors, etc.). In some embodiments, controllers  1772  and  1773  may be structured and/or operated in much the same way as controllers  1272  and  1273  of  FIG.  12   , respectively. Furthermore, in some embodiments, controllers  1772  and  1773  may receive commands from another controller (not shown), such as controller  1271 , and send data to that controller. 
     Sensor  1776  may be used to determine whether a culture plate is ready to be stacked. For example, sensor  1776  may be used to determine whether a culture plate is positioned beneath clamping mechanism  1710 . In some embodiments, sensor  1776  may be an optical sensor (e.g., SICK&#39;s VTE6-P3121S01 Photoelectric Proximity Sensor). As shown, lift pad  1734  includes a hole  1739  through which sensor  1776  can transmit and/or receive signals. For example, sensor  1776  can transmit light signals and receive reflected light signals through hole  1739 . When an object, such as a culture plate, is above sensor  1776 , the light initially transmitted by sensor  1776  is reflected back to it through hole  1739 . When this occurs, sensor  1776  may send controller  1772  a signal indicating that a culture plate is positioned above it. In some embodiments, the detection distance of sensor  1776  can be adjusted using a dial (not shown). 
     Sensors  1777 ,  1778 , and  1779  may be used to determine whether lift pad  1734  is in a particular position. For example, sensor  1277  may be used to determine whether lift pad  1734  is in the position illustrated in  FIG.  17 ( i ) , sensor  1278  may be used to determine whether lift pad  1734  is in the position illustrated in  FIG.  17 ( j ) , and sensor  1279  may be used to determine whether lift pad  1734  is in the position illustrated in  FIG.  17 ( k ) . In some embodiments, sensors  1777 ,  1778 , and/or  1779  may be U-shaped optical sensors (e.g., Panasonic&#39;s PM-Y45 Photoelectric Sensor). In some such embodiments, sensors  1777 ,  1778 , and/or  1779  may send signals to controller  1772  when an object (e.g., an arm  1737  of lift pad  1734 ) breaks a beam of light between the two sides of the U-shape of sensors  1777 ,  1778 , and/or  1779 . In some embodiments, additional sensors that are structured and/or operated in much the same way as sensors  1777 ,  1778 , and/or  1779  may be included in automated stacker and de-stacker  1700  to determine whether other components, such as clamping mechanism  1710 , are in a particular position. 
     As shown in  FIG.  17 ( a )  automated stacker and de-stacker  1700  may be incorporated into an automated specimen processing system including stage  1701 , belt  1702 , belt  1703 , belt  1704 , belt  1705 , wall  1708 , and wall  1709 . During operation, a culture plate may travel along belts  1704  and  1705  towards automated stacker and de-stacker  1700 . Walls  1708  and  1709  may help guide the culture plate towards automated stacker and de-stacker  1700  by ensuring that the culture plate does not slide off of belts  1704  and  1705 . In some embodiments, belts  1702  and  1703  may form part of a main track (e.g., main track  210 ) and belts  1704  and  1705  may form part of a main track (e.g., side track  220 ). In such embodiments, the automated specimen processing system may also include one or more mechanisms for transferring culture plates between the main track and the side track (e.g., off-ramp catcher  252  and/or on-ramp catcher  254 ). 
     As shown in  FIG.  17 ( b )  automated stacker and de-stacker  1700  includes two separate components. One component includes motor  1732 , lift pad  1734 , pin  1742 , pin  1744 , and controller  1772 . This component may be coupled to a bottom surface of stage  1701 . The other component includes clamping mechanism  1710 , motor  1722 , and controller  1773 . As shown in  FIG.  17 ( a ) , this component may be coupled to walls  1708  and  1709  through support beams  1713  and  1715 . In other embodiments, the components of automated stacker and de-stacker  1700  may be more integrated. For example, a single controller may control motors  1722  and  1732 . 
     As shown in  FIGS.  17 ( c ) and  17 ( d ) , spring  1716  extends from clamp  1712  to clamp  1714 . Furthermore, bearing block  1764 , bearing block  1766 , and bearing block  1768  are coupled to clamp  1712 , clamp  1714 , and bi-directional lead screw  1724 , respectively. During operation, motor  1722  may rotate bi-directional lead screw  1724  clockwise or counterclockwise in order to open or close clamping mechanism  1710 . For example, in order to open clamping mechanism  1710 , motor  1722  may rotate bi-directional lead screw  1724  such that bearing block  1768  moves downward. Due to the wedge-like shape of bearing block  1768 , as it moves downward, it pushes bearing blocks  1764  and  1766  in an outward direction. For example, from the perspective of FIGS.  17 ( c ) and  17 ( d ), as bearing block  1768  moves downward, bearing block  1768  pushes bearing block  1764  in a leftward direction, and it pushes bearing block  1766  in a rightward direction. Similarly, in order to close clamping mechanism  1710 , motor  1722  may rotate bi-directional lead screw  1724  such that bearing block  1768  moves upward. As bearing block  1768  moves upward, spring  1716  pulls bearing blocks  1764  and  1766  in an inward direction. For example, from the perspective of  FIGS.  17 ( c ) and  17 ( d ) , as bearing block  1768  moves downward, spring  1716  pulls bearing block  1764  in a rightward direction, and it pulls bearing block  1766  in a leftward direction. 
     Advantageously, much like clamping mechanism  1110 , clamping mechanism  1710  does not require any electricity to stay in a closed position because the clamping force is provided by spring  1716 . Electricity is used in this embodiment to open clamping mechanism  1710 . Therefore, in the event of a power outage, a stack of culture plates will remain clamped and secured in automated stacker and de-stacker  1700 . Furthermore, by using spring  1716 , clamping mechanism  1710  can easily adapt to culture plates with different diameters. 
     As shown in  FIGS.  17 ( e ) and  17 ( f ) , motor  1732  is connected to lift pad  1734  via lead screw  1738 . Furthermore, a linear guideway  1750  is coupled to lift pad  1734 . Linear guideway  1750  includes rail  1752  and bearing block  1754 . Lift pad  1734  is coupled to rail  1752 , which can slide upwards and downwards through bearing block  1754 . Bearing block may be coupled to another stationary component, such as a bottom surface of stage  1701 . During operation, motor  1732  may rotate lead screw  1738  clockwise or counterclockwise in order to raise or lower lift pad  1734 . As lift pad  1734  is raised and lowered by motor  1732 , linear guideway  1750  provides stability to lift pad  1734 . As shown in  FIG.  17 ( e ) , lift pad  1734  is in a lowered state. As shown in  FIG.  17 ( f ) , lift pad  1734  is in a raised state. 
     Advantageously, lift pad  1734  includes posts  1733  and  1735 , which provide additional support for a culture plate being stacked or de-stacked by automated stacker and de-stacker  1700 . As shown, the top surfaces of posts  1733  and  1735  are approximately coplanar with a central pad  1731  of lift  1734 . Furthermore, the gaps between posts  1733  and  1735  and central pad  1731  are large enough to accommodate belts  1704  and  1705 . As a result, belts  1704  and  1705  do not impede the upward or downward movement of lift pad  1734 . In some embodiments, lift pad  1734  may include additional posts. Furthermore, in some embodiments, posts  1733  and/or  1735  may be omitted from lift pad  1734 . For example, lift pad  1734  may be structured more like lift pad  1134  (see, e.g.,  FIG.  11 ( b ) ). Similarly, in some embodiments, lift pad  1134  may be structured more like lift pad  1734  and include one or more posts that offer additional support for a culture plate being stacked or de-stacked by automated stacker and de-stacker  1100 . 
     As shown in  FIGS.  17 ( g ) and  17 ( h ) , pins  1742  and  1744  are urged upward by springs  1746  and  1748 , respectively. Furthermore, pin  1742  is coupled to pin  1744  via plate  1745 . Springs  1746  and  1748  are positioned beneath plate  1745 . The upward and downward movement of pins  1742  and  1744  is guided by guide structure  1756 . In some embodiments, springs  1746  and  1748  may be configured to raise pins  1742  and  1744  by 6.5 mm to a position that is 4 mm above stage  1701 . In some embodiments, springs  1746  and  1748  are conical compression springs, which, advantageously, can be fully flattened when compressed and minimize the space required by automated stacker and de-stacker  1700 . As shown in  FIG.  17 ( g ) , pins  1742  and  1744  are fully raised. As shown in  FIG.  17 ( h ) , pins  1742  and  1744  are partially retracted. In some embodiments, pins  1742  and  1744  are configured to contact a base (not a lid) of a culture plate. In other embodiments, pins  1742  and  1744  are configured to contact a lid of a culture plate. 
     As shown in  FIGS.  17 ( i )- 17 ( k ) , lift pad  1734  may be used to lower pins  1742  and  1744 . As a result, motor  1732  can advantageously be used to actuate lift pad  1734 , post  1733 , post  1735 , pin  1742 , and pin  1744 . However, in other embodiments, multiple motors can be used to actuate these components. As shown in  FIG.  17 ( i ) , lift pad  1734  may be lowered by motor  1732  to a position where a base  1736  of lift pad  1734  contacts an arm  1747  of plate  1745  and applies a downward force to springs  1746  and  1748 . As shown in  FIG.  17 ( j ) , lift pad  1734  may be raised by motor  1732  to a position where base  1736  touches arm  1747  without applying a significant downward force to springs  1746  and  1748 . As shown in  FIG.  17 ( k ) , lift pad  1734  may be raised by motor  1732  to a position where base  1736  does not touch arm  1747 . As shown in  FIGS.  17 ( j ) and  17 ( k ) , pins  1742  and  1744  are fully raised. 
     In some embodiments, one or more blocks of methods  1300  and/or  1500  may be performed by automated stacker and de-stacker  1700 . For example, as shown in  FIG.  17 ( i ) , automated stacker and de-stacker  1700  may be initialized such that lift pad  1734 , pin  1742 , and pin  1744  are positioned below belts  1704  and  1705 . Therefore, blocks  1310  and/or  1510  may be performed by automated stacker and de-stacker  1700 . As another example, as explained above, motor  1732  may raise or lower lift pad  1734  and/or pins  1742  and  1744 . Therefore, blocks  1320 ,  1330 ,  1340 ,  1370 ,  1380 ,  1520 ,  1530 ,  1560 , and/or  1570  may be performed by automated stacker and de-stacker  1700 . As yet another example, as explained above, motor  1722  may open or close clamping mechanism  1710 . Therefore, blocks  1350 ,  1360 ,  1540 , and/or  1550  may be performed by automated stacker and de-stacker  1700 . 
       FIGS.  18 ( a )- 18 ( q )  illustrate stopping mechanisms that may be used alone or in combination with any of the automated stackers and de-stackers described above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ). For example, one or more of these stopping mechanisms may replace stopping mechanisms  242 ,  244 , and/or  246  in conveyor system  200 . As another example, one or more of the stopping mechanisms of  FIGS.  18 ( a )- 18 ( q )  may replace the pins and/or associated components of any of the automated stackers and de-stackers described above (e.g., pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 , and  1744 ). 
     As shown in  FIGS.  18 ( a )- 18 ( c ) , a stopping mechanism may include pins  1842 A and  1844 A. As shown in  FIG.  18 ( a ) , pins  1842 A and  1844 A may be positioned along a side track  1820  having belts  1822  and  1824 . During operation, an off-ramp catcher  1850  may transfer culture plates, such as culture plate  1806 , to side track  1820  from a main track  1810  having belts  1812  and  1814 . As shown, off-ramp catcher  1850  includes arm  1852 , pivot joint  1854 , and post  1856 . Off-ramp catcher  1850  may operate in much the same way as off-ramp catcher  252  and/or on-ramp catcher  254 . For example, during operation, off-ramp catcher  1850  may be rotated clockwise about pivot joint  1854  such that arm  1852  extends across belts  1812  and  1814 . While in this position, off-ramp catcher  1850  may prevent a culture plate from further traveling along main track  1810 . Sensor  1876  may be used to confirm that a culture plate has been stopped by off-ramp catcher  1850 . After stopping a culture plate in this manner, off-ramp catcher  1850  may be rotated counter-clockwise about pivot joint  1854  and push the stopped culture plate onto side track  1820 . During operation, pins  1842 A and  1844 A may be raised to prevent a culture plate from further traveling along side track  1820 . Similarly, stopper  1860  may be used to prevent a culture plate from further traveling along side track  1820 . Sensors, such as sensor  1878 , may be used to confirm that a culture plate has been stopped by pins  1842 A and  1844 A and/or stopper  1860 . Walls  1808  and  1809  may help guide the culture plate along side track  1820 . 
       FIG.  18 ( b )  provides a top-view of culture plate  1806 , which has been stopped by pins  1842 A and  1844 A.  FIG.  18 ( c )  illustrates a cross-section taken along line A of  FIG.  18 ( b ) . As shown, pins  1842 A and  1844 A are configured to contact a base  1805  (not a lid  1807 ) of culture plate  1806 . As discussed above, this configuration advantageously minimizes the distance pins  1842 A and  1844 A need to be raised and lowered. In embodiments where the space underneath side track  1820  is scarce, this is particularly important. However, pins  1842 A and  1844 A should still be raised to a sufficient height above side track  1820  (e.g., 4 mm) that prevents culture plate  1806  from jumping over pins  1842 A and  1844 A. Similarly, pins  1842 A and  1844 A should be lowered to a sufficient height below side track  1820  that allows culture plate  1806  to pass over pins  1842 A and  1844 A (e.g., 2.5 mm). 
     As shown in  FIG.  18 ( d ) , pins  1842 A and  1844 A may modified to contact lid  1807  of culture plate  1806 . In the side-view of  FIG.  18 ( d ) , pin  1842 A has been replaced with pin  1842 B. One potential disadvantage of this configuration is that a collision between, for example, pin  1842 B and lid  1807  may dislodge lid  1807  from base  1805 . Since pins  1842 A and  1844 A are configured to contact base  1805  (not lid  1807 ) of culture plate  1806 , the stopping mechanism of  FIGS.  18 ( a )- 18 ( c )  addresses this potential problem. 
     However, as shown in  FIGS.  18 ( e ) and  18 ( f ) , different risks are present when culture plate  1806  is replaced with, for example, a carrier  1881 A and a sample vessel  1882 . As noted above, the automated specimen processing systems described herein may be used to handle a variety of different objects. Culture plates are commonly used carriers for transporting biological samples. However, other types of objects, such as slides, cartridges, and vessels (e.g., tubes, screw-top containers, etc.), may be used for transporting biological samples. As shown in  FIGS.  18 ( e ) and  18 ( f ) , carrier  1881 A carries sample vessel  1882  as it travels along side track  1820 . The structure of sample vessel  1882  may be such that it cannot safely and/or reliably travel along side track  1820  without carrier  1881 A. For example, sample vessel  1882  may be a tube that is both fragile and prone to getting stuck between belts  1822  and  1824 . In some embodiments, carrier  1881 A may have a circular profile with a comparable diameter to culture plate  1806 . However, as shown, carrier  1881 A may be taller than culture plate  1806 . 
     As shown in  FIGS.  18 ( e ) and  18 ( f ) , pin  1842 A contacts carrier  1881 A at a lower point than pin  1842 B. As a result, there is an increased risk that sample vessel  1882  will tip in response to a collision between, for example, pin  1842 A and carrier  1881 A. However, as explained above, the height of pin  1842 A is advantageous for culture plates. The stopping mechanisms illustrated in  FIGS.  18 ( g )- 18 ( n )  combine some of the advantages offered by the stopping mechanisms described in relation to  FIGS.  18 ( a )- 18 ( f ) . 
     For example, as shown in  FIGS.  18 ( g ) and  18 ( h ) , pin  1842 A has been replaced with pin  1842 C. In contrast to pin  1842 B, pin  1842 C includes a recess  1883 C. As shown in  FIG.  18 ( g ) , carrier  1881 A contacts both an upper portion  1884 C and a lower portion  1885 C of pin  1842 C. As a result, pin  1842 C contacts carrier  1881 A at a higher point than pin  1842 A. Therefore, there is a decreased risk that sample vessel  1882  will tip in response to a collision between, for example, pin  1842 C and carrier  1881 A. Furthermore, as shown in  FIG.  18 ( h ) , base  1805  of culture plate  1806  contacts lower portion  1885 C of pin  1842 C. Lid  1807  of culture plate  1806  is received in recess  1883 C, but it does not contact pin  1842 C. As a result, there is a decreased risk that lid  1807  will be dislodged from base  1805 . 
     As another example, as shown in  FIGS.  18 ( i ) and  18 ( j ) , pin  1842 A has been replaced with pin  1842 D. In contrast to pin  1842 C, an upper portion  1884 D of pin  1842 D has an increased width. As shown in  FIG.  18 ( i ) , carrier  1881 A contacts only upper portion  1884 D (not a lower portion  1885 D) of pin  1842 D. As a result, pin  1842 D also contacts carrier  1881 A at a higher point than pin  1842 A. Therefore, there is a decreased risk that sample vessel  1882  will tip in response to a collision between, for example, pin  1842 D and carrier  1881 A. Furthermore, as shown in  FIG.  18 ( j ) , base  1805  of culture plate  1806  contacts lower portion  1885 D of pin  1842 D. Lid  1807  of culture plate  1806  is received in a recess  1883 D, but it does not contact pin  1842 D. As a result, there is a decreased risk that lid  1807  will be dislodged from base  1805 . 
     As yet another example, as shown in  FIG.  18 ( k ) , pin  1842 A has been replaced with pin  1842 E, and carrier  1881 A has been replace with carrier  1881 B. In contrast to the embodiments, of  FIGS.  18 ( g )- 18 ( j ) , both pin  1842 A and carrier  1881 A have been modified. As shown, a lip  1886 B of carrier  1881 B contacts a narrow upper portion  1884 E of pin  1842 E. As a result, pin  1842 E contacts carrier  1881 B at a higher point than pin  1842 A contacts carrier  1881 A. Therefore, there is a decreased risk that sample vessel  1882  will tip in response to a collision between, for example, pin  1842 E and carrier  1881 B. Furthermore, as shown in  FIG.  18 ( l ) , base  1805  of culture plate  1806  contacts a wide lower portion  1885 E of pin  1842 E. Since upper portion  1884 E has a smaller width than lower portion  1885 E, lid  1807  of culture plate  1806  does not contact pin  1842 E. As a result, there is a decreased risk that lid  1807  will be dislodged from base  1805 . 
     As yet another example, as shown in  FIG.  18 ( m ) , pin  1842 A has been replaced with pin  1842 F, and carrier  1881 A has been replace with carrier  1881 C. In contrast to pin  1842 E, a narrow upper portion  1884 F of pin  1842 F also includes an extension  1883 F. Furthermore, in contrast to carrier  1881 B, carrier  1881 C has a lip  1886 C with a recess  1887 . As shown, lip  1886 C contacts portion  1884 F. Furthermore, recess  1887  receives extension  1883 F. As a result, pin  1842 F contacts carrier  1881 C at a higher point than pin  1842 A contacts carrier  1881 A. Therefore, there is a decreased risk that sample vessel  1882  will tip in response to a collision between, for example, pin  1842 F and carrier  1881 C. Furthermore, as shown in  FIG.  18 ( n ) , base  1805  of culture plate  1806  contacts a wide lower portion  1885 F of pin  1842 F. Since upper portion  1884 F has a smaller width than lower portion  1885 F and extension  1883 F is positioned above culture plate  1806 , lid  1807  of culture plate  1806  does not contact pin  1842 F. As a result, there is a decreased risk that lid  1807  will be dislodged from base  1805 . 
     Those skilled in the art will appreciate that various modifications can be made to the stopping mechanisms of  FIGS.  18 ( a )- 18 ( n ) . For example, a resilient element, such as a spring, may be added to any of the stopping mechanisms of  FIGS.  18 ( a )- 18 ( l )  to reduce the collision forces with culture plate  1806  and/or carriers  1881 A,  1881 B, and/or  188 C. For example, as shown in  FIG.  18 ( o ) , a wide lower portion  1885 F of a pin  1842 G may extend below belt  1822  and be coupled with a resilient element  1888 . When lip  1886 B of carrier  1881 B contacts a narrow upper portion  1884 G of pin  1842 G, resilient element  1888  will compress and absorb some of the collision forces. This configuration may also reduce the noise created by such a collision. As another example, any of the pins of the stopping mechanisms of  FIGS.  18 ( a )- 18 ( n )  may be configured to rotate in order to rotate culture plate  1806  and/or carriers  1881 A,  1881 B, and/or  188 C. For example, as shown in  FIG.  18 ( p ) , a pin  1842 H may be configured to rotate. In some embodiments, a motor (not shown) may be coupled to a wider lower portion  1885 H of pin  1842 H. While lip  1886 B of carrier  1881 B contacts a narrow upper portion  1884 H of pin  1842 H, pin  1842 H may be rotated in order to rotate carrier  1881 B. As carrier  1881 B rotates, a scanner  1889  may scan carrier  1881 B and/or sample vessel  1882  for a barcode and/or another identifying mark. As yet another example, the number of pins included in the stopping mechanisms of  FIGS.  18 ( a )- 18 ( n )  may be increased or decreased. For example, as shown in  FIG.  18 ( q ) , a single pin  1841  in combination with walls  1808  and  1809  can be used to stop culture plate  1806 . 
       FIGS.  19 ( a )- 19 ( e )  illustrate another stopping mechanism that may be used alone or in combination with any of the automated stackers and de-stackers described above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ). For example, the stopping mechanism of  FIGS.  19 ( a )- 19 ( e )  may replace stopping mechanisms  242 ,  244 , and/or  246  in conveyor system  200 . As another example, the stopping mechanism of  FIGS.  19 ( a )- 19 ( e )  may replace the pins and/or associated components of any of the automated stackers and de-stackers described above (e.g., pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 ,  1744 ,  1841 ,  1842 A, and  1844 A). 
     As shown in  FIGS.  19 ( a )- 19 ( e ) , a stopping mechanism may include a platform  1941 , a pin  1943 , and a pin  1944 . As shown in the top-view of  FIG.  19 ( e ) , platform  1941  may be positioned on a stage  1901  between belts  1922  and  1924 .  FIGS.  19 ( a )- 19 ( d )  are cross-sections taken along line B of  FIG.  19 ( e ) . As shown in  FIGS.  19 ( a )- 19 ( d ) , pin  1944  may be positioned beneath platform  1941  and extend through stage  1901 . As shown in  FIG.  19 ( a ) , during operation, a culture plate  1906  may travel along belts  1922  and  1924  towards platform  1941 . As shown in  FIG.  19 ( b ) , when all or some of culture plate  1906  is above platform  1941 , pin  1944  may be raised. As pin  1941  is raised, it exerts an upward force on platform  1941  that causes platform  1941  to rotate counter-clockwise about pin  1943 . As shown in  FIG.  19 ( c ) , culture plate  1906  has stopped moving. More specifically, culture plate  1906  is resting above belts  1922  and  1924  on platform  1941 . As shown in  FIG.  19 ( d ) , pin  1944  may be lowered in order to lower culture plate  1906  back onto belts  1922  and  1924 . As pin  1941  is lowered, the weight of platform  1941  causes it to rotate clockwise about pin  1943 . Culture plate  1906  may then travel along belts  1922  and  1924  away from platform  1941 . 
     In some embodiments, compressed air may be used to raise or lower pin  1944 . In some embodiments, since pin  1944  does not need to be raised or lowered a great distance, an electric motor (not shown), such as an AC motor, a DC motor, or a stepper motor, may be used to raise or lower pin  1941 . In some embodiments, pin  1944  may operate in much the same way as pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 ,  1744 ,  1841 ,  1842 A, and/or  1844 A. 
     In some embodiments, a sensor (not shown) may be used to confirm that all or some of culture plate  1906  is above platform  1941 . In some embodiments, the sensor may be a fiber optic sensor. In some embodiments, the sensor may be positioned alongside belts  1922  or  1924 . In some embodiments, the sensor may be coupled to platform  1941 . In some embodiments, the sensor may be positioned beneath a hole (not shown) in platform  1941 . In such embodiments, the sensor may operate in much the same way as sensor  1776  by transmitting and/or receiving signals through the hole in platform  1941 . For example, the sensor can transmit light signals and receive reflected light signals through the hole in platform  1941 . 
     In comparison to the stopping mechanisms of  FIGS.  18 ( a )- 18 ( q ) , the stopping mechanism of  FIGS.  19 ( a )- 19 ( e )  may produce less noise. In many conveyor systems, the belts of a track will often continue to move regardless of whether a culture plate has been stopped by, for example, one of the stopping mechanisms of  FIGS.  18 ( a )- 18 ( q )  or the stopping mechanism of  FIGS.  19 ( a )- 19 ( e ) . However, when a culture plate is stopped by one of the stopping mechanisms of  FIGS.  18 ( a )- 18 ( q ) , the belts will rub against the base of the culture plate and create noise. In contrast, when a culture plate is stopped by the stopping mechanism of  FIGS.  19 ( a )- 19 ( e ) , there is no contact between the culture plate and the belts. 
       FIGS.  20 ( a ) and  20 ( b )  illustrate yet another stopping mechanism that may be used alone or in combination with any of the automated stackers and de-stackers described above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ). For example, the stopping mechanism of  FIGS.  20 ( a ) and  20 ( b )  may replace stopping mechanisms  242 ,  244 , and/or  246  in conveyor system  200 . As another example, the stopping mechanism of  FIGS.  20 ( a ) and  20 ( b )  may replace the pins and/or associated components of any of the automated stackers and de-stackers described above (e.g., pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 ,  1744 ,  1841 ,  1842 A, and  1844 A). 
     As shown in  FIGS.  20 ( a ) and  20 ( b ) , a stopping mechanism may include a platform  2041 , a pin  2043 , a pin  2042 , and a pin  2044 . As shown in the top-view of  FIG.  20 ( a ) , platform  2041  may be positioned on a stage  2001  alongside a belt  2024 . Furthermore, pin  2042  may be positioned on stage  2001  alongside a belt  2022 .  FIG.  20 ( b )  is a cross-section taken along line C of  FIG.  20 ( a ) . As shown in  FIG.  20 ( b ) , pin  2044  may extend through stage  2001 . Similarly, pin  2042  may also and extend through stage  2001 . The stopping mechanism of  FIGS.  20 ( a ) and  20 ( b )  may operate in much the same way as the stopping mechanism of  FIGS.  19 ( a )- 19 ( e ) . For example, when all or some of culture plate  2006  is above platform  2041 , pins  2042  and  2044  may be raised. As pin  2044  is raised, it exerts an upward force on platform  2041  that causes platform  2041  to rotate counter-clockwise about pin  2043 . As shown in  FIG.  20 ( b ) , culture plate  2006  has stopped moving. More specifically, a portion of culture plate  2006  is held above belts  2022  and  2024  by platform  2041 . Furthermore, pin  2042  is supporting culture plate  2006  and helping to ensure that culture plate  2006  does not slide off of platform  2041 . Pins  2042  and  2044  may be lowered in order to lower culture plate  2006  back onto belts  2022  and  2024 . As pin  2041  is lowered, the weight of platform  2041  causes it to rotate clockwise about pin  2043 . Culture plate  2006  may then travel along belts  2022  and  2024  away from platform  2041 . 
     In some embodiments, compressed air may be used to raise or lower pins  2042  and  2044 . In some embodiments, since pins  2042  and  2044  do not need to be raised or lowered a great distance, an electric motor (not shown), such as an AC motor, a DC motor, or a stepper motor, may be used to raise or lower pin  2041 . In some embodiments, pins  2042  and  2044  may operate in much the same way as pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 ,  1744 ,  1841 ,  1842 A, and/or  1844 A. 
     As shown in  FIG.  20 ( a ) , a sensor  2076  may be positioned on stage  2001  between belts  2022  and  2024  and used to confirm that all or some of culture plate  2006  is above platform  2041 . In some embodiments, sensor  2076  may be a fiber optic sensor. In other embodiments, sensor  2076  may be moved to a different location. For example, sensor  2076  may be positioned alongside belts  2022  or  2024 . In other embodiments, sensor  2076  may be coupled to platform  2041 . In other embodiments, sensor  2076  may be positioned beneath a hole (not shown) in platform  2041 . In such embodiments, sensor  2076  may operate in much the same way as sensor  1776  by transmitting and/or receiving signals through the hole in platform  2041 . For example, sensor  2076  can transmit light signals and receive reflected light signals through the hole in platform  2041 . 
     In comparison to the stopping mechanisms of  FIGS.  18 ( a )- 18 ( q ) , the stopping mechanism of  FIGS.  20 ( a ) and  20 ( b )  may produce less noise. In many conveyor systems, the belts of a track will often continue to move regardless of whether a culture plate has been stopped by, for example, one of the stopping mechanisms of  FIGS.  18 ( a )- 18 ( q )  or the stopping mechanism of  FIGS.  20 ( a ) and  20 ( b ) . However, when a culture plate is stopped by one of the stopping mechanisms of  FIGS.  18 ( a )- 18 ( q ) , the belts will rub against the base of the culture plate and create noise. In contrast, when a culture plate is stopped by the stopping mechanism of  FIGS.  20 ( a ) and  20 ( b ) , there is no contact between the culture plate and the belts. 
     Those skilled in the art will appreciate that various modifications can be made to the stopping mechanism of  FIGS.  20 ( a ) and  20 ( b ) . For example, the positions of platform  2041  and pin  2042  may be reversed such that platform  2041  is positioned on stage  2001  alongside belt  2022 , and pin  2042  is positioned on stage  2001  alongside a belt  2024 . As another example, platform  2041  may be positioned on stage  2001  between belts  2022  and  2024 . As yet another example, pin  2042  may be replaced with a second platform hingedly engaged with a pin that operates in conjunction with platform  2041  to stop an incoming culture plate. As yet another example, platform  2041  may be rotated by a different mechanism than pin  2042 . 
       FIG.  21    illustrates yet another stopping mechanism (i.e., flipper stopper  2100 ) that may be used alone or in combination with any of the automated stackers and de-stackers described above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ). For example, flipper stopper  2100  may replace stopping mechanisms  242 ,  244 , and/or  246  in conveyor system  200 . As another example, flipper stopper  2100  may replace the pins and/or associated components of any of the automated stackers and de-stackers described above (e.g., pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 ,  1744 ,  1841 ,  1842 A, and  1844 A). 
     As shown, flipper stopper  2100  includes flippers  2142  and  2144 , a housing  2190 , actuators  2191 ,  2192 ,  2193 , and  2194 , and shafts  2195 ,  2196 , and  2197 . Actuators  2191 ,  2192 ,  2193 , and  2194  are disposed within housing  2190 . In some embodiments, one or more of actuators  2191 ,  2192 ,  2193 , and  2194  may be voice coil actuators. For example, one or more of actuators  2191 ,  2192 ,  2193 , and  2194  may be moving magnet actuators or moving coil actuators. In some embodiments, one or more of actuators  2191 ,  2192 ,  2193 , and  2194  may be pneumatic actuators. As shown, flipper  2142  is rotatably coupled to housing  2190  through shaft  2195 . As a result, flipper  2142  can rotate about an axis defined by shaft  2195 . Flipper  2142  is also coupled to actuators  2192  and  2194  through shafts  2197  and  2196 , respectively. As shown, actuators  2192  and  2194  can push or pull flipper  2142 . During such operations, shafts  2197  and  2196  slide back and forth in slots (e.g., slot  2198 ) defined in housing  2190 . The length of these slots may limit the movement of flipper  2142 . Although not easily seen from the perspective of  FIG.  21   , flipper  2144  is also be coupled to housing  2190  and actuators  2191  and  2193  in a similar manner (i.e., through three separate shafts). As shown, flippers  2142  and  2144  include two roughly straight edges separated by an angular bend. However, in other embodiments, the edges and/or bends of flippers  2142  and/or  2144  may be curved. Similarly, in other embodiments, flippers  2142  and  2144  may be curved without any bends. 
     During operation, flipper stopper  2100  may stop culture plates traveling along belts  2122  and  2124 . For example, as shown, flipper stopper  2100  has stopped a culture plate  2106 . To reach this position, actuators  2191  and  2192  pushed flippers  2142  and  2144  outward, and actuators  2193  and  2194  pulled flippers  2142  and  2144  inward. As a result, flippers  2142  and  2144  rotate in opposite directions and prevent culture plate  2106  from further traveling along belts  2122  and  2124 . A similar operation may be performed to permit culture plate  2106  to travel along belts  2122  and  2124 . For example, actuators  2191  and  2192  may pull flippers  2142  and  2144  inward, and actuators  2193  and  2194  may push flippers  2142  and  2144  outward. Advantageously, such an operation may also prevent another culture plate (not shown) traveling along belts  2122  and  2124  from passing through flippers  2142  and  2144 . Therefore, when operated in this manner, only a single culture plate may pass through flippers  2142  and  2144  at a time. 
     As noted above, in some embodiments, flipper stopper  2100  may replace the pins and/or associated components of any of the automated stackers and de-stackers described above (e.g., pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 , and  1744 ). In such embodiments, housing  2190  may be positioned beneath the lift pads of those systems (e.g., lift pads  334 ,  1134 ,  1434 ,  1634 , and  1734 ). Furthermore, in such embodiments, the lengths of the shafts (e.g., shafts  2195 ,  2196 , and  2197 ) connecting flippers  2142  and  2144  to housing  2190  and actuators  2191 ,  2192 ,  2193 , and  2194  may be increased to compensate for the lift pad. 
       FIGS.  22 ( a )- 22 ( c )  illustrate yet another stopping mechanism (i.e., flipper stopper  2200 ) that may be used alone or in combination with any of the automated stackers and de-stackers described above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ). For example, flipper stopper  2200  may replace stopping mechanisms  242 ,  244 , and/or  246  in conveyor system  200 . As another example, flipper stopper  2200  may replace the pins and/or associated components of any of the automated stackers and de-stackers described above (e.g., pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 ,  1744 ,  1841 ,  1842 A, and  1844 A). 
     As shown, flipper stopper  2200  includes a flipper  2241 , a housing  2290 , an actuator  2291 , a guide structure  2294 , shaft  2296 , and shaft  2297 . In comparison to  FIG.  22 ( a ) , a portion of housing  2290  has been removed in  FIGS.  22 ( b ) and  22 ( c )  to reveal some of the components within housing  2290 , such as actuator  2291 . As shown, actuator  2291  includes casing  2292  and piston  2293 . Guide structure  2292  is coupled to piston  2293 . In some embodiments, actuator  2291  may be a voice coil actuator. For example, actuator  2291  may be a moving magnet actuator or a moving coil actuator. In some embodiments, actuator  2291  may be a pneumatic actuator. As shown, flipper  2241  is rotatably coupled to housing  2290  through shaft  2296 . As a result, flipper  2241  can rotate about an axis defined by shaft  2296 . Flipper  2241  is also coupled to shaft  2297 , which extends through a slanted slot  2295  of guide structure  2294 . As shown, flipper  2241  includes two roughly straight edges separated by an angular bend. However, in other embodiments, the edges and/or bend of flipper  2241  may be curved. Similarly, in other embodiments, flipper  2241  may be curved without any bends. 
     During operation, piston  2293  (and consequently guide structure  2294 ) may oscillate between the two positions illustrated in  FIGS.  22 ( b ) and  22 ( c ) . Since shaft  2297  extends through slot  2295  of guide structure  2294 , the oscillation of piston  2293  will also cause shaft  2297  to oscillate in directions approximately perpendicular to the directions of oscillation of piston  2293 . Furthermore, since shaft  2297  is coupled to flipper  2241 , the oscillation of shaft  2297  will also cause flipper  2241  to rotate about the axis defined by shaft  2296 . 
     Much like flipper stopper  2100 , flipper stopper  2200  may stop culture plates traveling along a conveyor track through the rotation of flipper  2241 . For example, flipper  2241  may be rotated in one direction to stop an incoming culture plate, and flipper  2241  may be rotated in an opposite direction to release that culture plate. In some embodiments, when flipper stopper  2200  is operated in this manner, only a single culture plate may pass through flipper stopper  2200  at a time. In some embodiments, a wall may be positioned across the conveyor track from flipper stopper  2200  (see, e.g., the position of flipper stopper  2300  in relation to a wall  2309  in  FIG.  23 ( a ) ) to stabilize a stopped culture plate. In some embodiments, a second flipper stopper may be positioned across the conveyor track from flipper stopper  2200 . In some such embodiments, the second flipper stopper may be structured and/or operated in much the same way as flipper stopper  2200 . In some embodiments, a sensor (e.g., a fiber optic sensor) may be used to confirm that a culture plate has been stopped and/or released by flipper stopper  2200 . 
       FIGS.  23 ( a )- 23 ( c )  illustrate yet another stopping mechanism (i.e., flipper stopper  2300 ) that may be used alone or in combination with any of the automated stackers and de-stackers described above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ). For example, flipper stopper  2300  may replace stopping mechanisms  242 ,  244 , and/or  246  in conveyor system  200 . As another example, flipper stopper  2300  may replace the pins and/or associated components of any of the automated stackers and de-stackers described above (e.g., pins  842 ,  844 ,  1142 ,  1144 ,  1442 ,  1444 ,  1642 ,  1644 ,  1742 ,  1744 ,  1841 ,  1842 A, and  1844 A). 
     As shown, flipper stopper  2300  includes a flipper  2341 , a housing  2390 , a controller  2391 , a motor  2392 , and an eccentric arm  2394 . In comparison to  FIG.  22 ( a ) , some or all of housing  2390  has been removed in  FIGS.  22 ( b ) and  22 ( c )  to reveal some of the components within housing  2390 , such as controller  2391  and motor  2392 . As shown, motor  2392  is coupled to eccentric arm  2394  through disc  2393 . In some embodiments, motor  2392  is an electric motor (e.g., AC motors, DC motors, stepper motors, etc.). As shown, flipper  2341  includes cylindrical extensions  2395  and  2396 . Furthermore, housing  2390  includes complementary cylindrical recesses (see, e.g., the transparent illustration of recess  2398  in  FIG.  22 ( b ) ) for receiving extensions  2395  and  2396 . As a result, flipper  2341  can rotate about an axis defined by extensions  2395  and  2396 . As shown, flipper  2341  also includes a recess  2397  through which a portion of eccentric arm  2394  extends. Flipper  2341  also includes two roughly straight edges separated by an angular bend. However, in other embodiments, the edges and/or bend of flipper  2341  may be curved. Similarly, in other embodiments, flipper  2341  may be curved without any bends. 
     During operation, controller  2391  may control motor  2392  to rotate disc  2393  (and consequently eccentric arm  2394 ). Since eccentric arm  2394  extends through recess  2397  of flipper  2341 , the rotation of eccentric arm  2394  will also cause flipper  2341  to rotate about the axis defined by extensions  2395  and  2396 . In some embodiments, controller  2391  may control motor  2392  to only rotate disc  2393  clockwise or counter-clockwise. In other embodiments, controller  2391  may control motor  2392  to alternate between rotating disc  2393  clockwise and counter-clockwise. 
     Much like flipper stoppers  2100  and  2200 , flipper stopper  2300  may stop culture plates traveling along belts  2322  and  2324  through the rotation of flipper  2341 . For example, flipper  2341  may be rotated in one direction to stop an incoming culture plate, and flipper  2341  may be rotated in an opposite direction to release that culture plate. In some embodiments, when flipper stopper  2300  is operated in this manner, only a single culture plate may pass through flipper stopper  2300  at a time. As shown, a wall  2309  may be positioned across belts  2322  and  2324  from flipper stopper  2300  to stabilize a stopped culture plate. However, in other embodiments, wall  2309  may be replaced with a second flipper stopper. In some such embodiments, the second flipper stopper may be structured and/or operated in much the same way as flipper stopper  2300 . As shown, a sensor  2376  (e.g., a fiber optic sensor) may be used to confirm that a culture plate has been stopped and/or released by flipper stopper  2300 . However, in other embodiments, sensor  2376  may be omitted or moved to a different location. 
     From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, a different clamping mechanism, such as the one illustrated in  FIG.  24   , can be integrated into any of the automated stackers and de-stackers discussed above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ). As shown, clamping mechanism  2400  includes base  2402 , clamp  2412 , clamp  2414 , spring  2422 , spring  2424 , gear  2432 , and gear  2434 . Clamp  2412  includes arms  2442  and  2444 . Clamp  2414  includes arm  2446 . As shown, arms  2442 ,  2444 , and  2446  include complementary sets of teeth that are configured to mesh together with the teeth of gears  2432  and  2434 . During operation, springs  2422  and  2424  pull clamps  2412  and  2424  into a closed position. However, an opposing force may be applied to, for example, arm  2446  of clamp  2414  in order to open clamping mechanism  2400 . In some embodiments, the opposing force maybe be applied through the use of an electric motor (e.g., AC motors, DC motors, stepper motors, etc.). 
     As another example, the shape of the clamping mechanisms described above (e.g., clamping mechanisms  310 ,  1110 ,  1410 ,  1610 , and  1710 ) can be modified. In many of the embodiments discussed above, the clamping mechanisms contacted the culture plates at four different points. However, in other embodiments, the clamping mechanism can, for example, be configured to contact the culture plates at three different points. Similarly, the clamping mechanism can, for example, be configured to contact the culture plates at five different points. Furthermore, in many of the embodiments discussed above, the contact points were along roughly straight edges separated by angular bends. However, in other embodiments, the edges and/or bends may be curved. Similarly, in other embodiments, the contact points may be along a singular curved edge. Moreover, in some embodiments, the contact points may include rollers mounted to the clamps of the clamping mechanism in order to reduce the amount of friction between the clamps and the culture plates. 
     As yet another example, a sensor can be added to any of the automated stackers and de-stackers discussed above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ) in order to detect the height of incoming culture plates. For example, in some embodiments, the clamping mechanism (e.g., clamping mechanisms  310 ,  1110 ,  1410 ,  1610 , and  1710 ) can be configured to clamp culture plates having heights with a predetermined range. However, by including a sensor configured to detect the height of incoming culture plates, that range can be expanded. More specifically, the height information obtained from the sensor can be used to adjust the height at which the clamping mechanism closes around a culture plate. 
     As yet another example, a gate stopper may be included in any of the automated specimen processing systems described above. For example, as illustrated in  FIG.  25   , a gate stopper may be included in automated specimen processing system  2500 . As shown, automated specimen processing system  2500  includes main track  2512 , side track  2514 , off-ramp catcher  2522 , on-ramp catcher  2524 , gate stopper  2530 , and automated stackers and de-stackers  2542 ,  2544 ,  2546 , and  2548 . During operation, an incoming culture plate may be transferred from main track  2512  to side track  2514  by off-ramp catcher  2522 . Once on side track  2514 , the culture plate may be stopped by gate stopper  2530  at a position preceding automated stackers and de-stackers  2542 ,  2544 ,  2546 , and  2548 . This may be done to prevent the incoming culture plate from interfering with the stacking and/or de-stacking of one or more other culture plates. In some embodiments, gate stopper  2530  may be controlled independently from automated stackers and de-stackers  2542 ,  2544 ,  2546 , and  2548 . In other embodiments, one or more motors in automated stackers and de-stackers  2542 ,  2544 ,  2546 , and/or  2548  may be used to control gate stopper  2530 . For example, a motor that controls one or more of the pins of automated stackers and de-stackers  2542 ,  2544 ,  2546 , and/or  2548  may be used to control gate stopper  2530 . 
     As yet another example, a pusher mechanism could be added to one or more of the cabinets of the automated stackers and de-stackers described above (e.g., cabinets  120 A,  130 A,  120 B,  130 B,  140 B,  150 B,  302 , and  1102 ). A pusher mechanism could be used to automatically push a stack of culture plates out of a cabinet and onto a plate cart of a workbench. In some embodiments, the pusher mechanism could be configured to push all of the culture plates in the cabinet except for the bottom culture plate that is clamped by the clamping mechanism. In other embodiments, the clamping mechanism may be opened and the bottom culture plate may be raised by the lift pad so that the entire stack of culture plates can be pushed out of the cabinet by the pusher mechanism. 
     As yet another example, any of the automated stackers and de-stackers discussed above (e.g., automated stackers and de-stackers  300 ,  1100 ,  1400 ,  1600 , and  1700 ) may be reconfigured such that the culture plates are stored beneath the conveyor system. For example, as shown in  FIGS.  26 ( a )- 26 ( b ) , automated specimen processing system  2600  includes a main track, a side track, automated stacker and de-stacker  2606 , and stage  2608 . The main track includes belts  2601  and  2602 . The side track includes belts  2603  and  2604 . Automated stacker and de-stacker  2606  includes actuator  2610 , actuator  2620 , and cabinet  2630 . Actuator  2620  can raise or lower a stack of culture plates (e.g., stack of culture plates  2644 ) in cabinet  2630 . During a stacking operation, actuator  2620  can raise or lower the stack of culture plates such that the top surface of the culture plate at the top of the stack of culture plates is approximately level with a top surface of stage  2608 . Furthermore, actuator  2610  can slide a culture plate (e.g., culture plate  2642 ) off of belts  2603  and  2604  of the side track and onto the stack of culture plates. During a de-stacking operation, actuator  2620  can raise or lower the stack of culture plates such that the top surface of the culture plate second from the top of the stack of culture plates is approximately level with a top surface of stage  2608 . Furthermore, actuator  2610  can slide the culture plate at the top of the stack of culture plates onto belts  2603  and  2604  of the side track. 
     In contrast to some of the embodiments discussed above, the embodiment of  FIGS.  26 ( a )- 26 ( b )  requires less accuracy because the culture plates do not need to be clamped within a predetermined range of heights. However, in this embodiment, an actuator is included in the cabinet housing the stack of culture plates. As a result, the cabinet is wider and has a larger footprint. Furthermore, the embodiment of  FIGS.  26 ( a )- 26 ( b )  does not split the interlocking rims on the lids and the bases of the culture plates. Therefore, a significant amount of force (e.g., 110 newtons) may need to be applied during a de-stacking operation. 
     As yet another example, any of the conveyor systems discussed above (e.g., conveyor systems  110 A,  110 B, and  200 ) may be modified to include a shortcut. For example, as shown in  FIG.  27   , a conveyor system  2700  may include a stage  1706 , a main track  2710  having belts  2712  and  2714 , a side track  2720  having belts  2722  and  2724 , a transfer track  2730  having belts  2732  and  2734 , pin  2742 , pin  2744 , pin  2746 , pin  2748 , transfer mechanism  2750 , transfer mechanism  2760 , and wheels  2770 . Wheels  2770  are included in conveyor system  2700  to bend portions of main track  2710 , side track  2720 , and transfer track  2730 . In other embodiments, one or more of the wheels  2770  may be added or removed. 
     As shown in  FIG.  27   , a culture plate  2701  is prevented from further traveling along transfer track  2730  by pins  2746  and  2748 , a culture plate  2702  is prevented from further traveling along side track  2720  by pins  2742  and  2744 , and a culture plate  2703  is being transferred from side track  2720  to transfer track  2730  by transfer mechanism  2750 . Transfer mechanism  2750  includes arm  2752 , pivot joint  2754 , post  2756 , and post  2758 . As shown, posts  2756  and  2758  contact culture plate  2703 . Furthermore, arm  2752  is supported by pivot joint  2754  at a height exceeding the height of culture plate  2703 . As a result, a portion of culture plate  2703  is positioned beneath arm  2752 . While culture plate  2703  is positioned in this manner, arm  2752  is rotated clockwise about pivot joint  2754 . This rotation of arm  2752  causes posts  2756  and  2758  to push culture plate  2703  from side track  2720  to transfer track  2730 . In some embodiments, this process may involve rotating arm  2752  clockwise until it is approximately perpendicular with side track  2720  and/or transfer track  2730  (e.g., within 30 degrees of this position). 
     A similar operation may be performed to transfer another culture plate, such as culture plate  2701  from transfer track  2730  to side track  2720 . For example, after culture plate  2703  is transferred to transfer track  2730 , arm  2752  may remain at a position that is approximately perpendicular with side track  2720  and/or transfer track  2730  and pins  2746  and  2748  may be lowered beneath stage  2706 . As a result, culture plate  2701  will travel along transfer track  2730  until it contacts posts  2756  and  2758 . While culture plate  2701  is positioned in this manner, arm  2752  is rotated counter-clockwise about pivot joint  2754 . This rotation of arm  2752  causes posts  2756  and  2758  to push culture plate  2701  from transfer track  2730  to side track  2720 . In some embodiments, this process may involve rotating arm  2752  counter-clockwise until it is approximately perpendicular with side track  2720  and/or transfer track  2730 . 
     After transferring a culture plate between side track  2720  and transfer track  2730 , arm  2752  may be rotated to a neutral position in which it is approximately parallel with side track  2720  and/or transfer track  2730 . While arm  2752  is in this neutral position, it does not interfere with culture plates traveling along side track  2720  and/or transfer track  2730 . 
     Transfer mechanism  2760  may operate in much the same way transfer mechanism  2750  to transfer culture plates between main track  2710  and transfer track  2730 . Furthermore, transfer mechanism  2760  may be rotated to a neutral position in which it is approximately parallel with main track  2710  and/or transfer track  2730 . Collectively, transfer track  2730 , transfer mechanism  2750 , and transfer mechanism  2760  provide a shortcut for transferring culture plates between main track  2710  and side track  2720 . In automated specimen processing systems comprising a plurality of modules, this shortcut may expedite the processing of biological samples by reducing the time spent transferring those samples between the plurality of modules. 
     In other embodiments, the structure of transfer mechanisms  2750  and/or  2760  may be modified. For example, post  2758  may be removed from transfer mechanisms  2750 . In such embodiments, transfer mechanisms  2750  may be structured much like off-ramp catcher  1850 . As another example, additional posts and/or structures for contacting culture plates may be added to transfer mechanism  2750 . As yet another example, the shape of arm  2752  of transfer mechanisms  2750  may be modified. For example, arm  2752  may be curved much like off-ramp catcher  252  or on-ramp catcher  254 . 
     As yet another example, any of the mechanisms described above may be integrated into any of the modules illustrated in  FIGS.  28 ( a )- 28 ( f ) .  FIG.  28 ( a )  illustrates a two-way highway module  2810  with an opening  2812 . As shown in  FIGS.  28 ( b ) and  28 ( c ) , opening  2812  may provide an interface for a variety of different mechanisms. For example, an automated output stacker  2814  or an automated stacker and de-stacker  2816  may be coupled to module  2810  through interface  2812 . Module  2810  may include a conveyor system that is structured and/or operated much like conveyor system  200 .  FIG.  28 ( d )  illustrates a one-way highway module  2820 . Module  2820  may only include a single conveyor track.  FIG.  28 ( e )  illustrates a 90-degree turn module  2830 , a T-intersection module  2840 , and a 180-degree turn module  2850 . Module  2830  may include one or more conveyor tracks with a 90-degree turn. Module  2840  may include a T-intersection between a plurality of conveyor tracks. Module  2850  may include one or more conveyor tracks with a 180-degree turn.  FIG.  28 ( f )  illustrates a shortcut module  2860 . Module  2860  may include a conveyor system that is structured and/or operated much like conveyor system  2700 . 
     While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.