Patent Application: US-3977008-A

Abstract:
the present invention provides an apparatus for the detection of volatile and semi - volatile chemicals using the olfactory abilities of honey bees that are trained to respond to the presence of a specific chemical in a sample of gas with the proboscis extension reflex . in particular , the geometry and arrangement of the parts of the apparatus are such that the amount of surface area in contact with the sample of gas prior to its introduction to the bees is minimized to improve the detection of particular volatile and semi - volatile that have a tendency to “ stick ” to contacting surfaces , especially certain chemicals associated with explosives and narcotics . according to another aspect of the present invention , a pre - concentrating means is incorporated with the device to effectively increase the concentration of “ sticky ” chemicals presented to the insects .

Description:
it is advantageous to define several terms before describing the invention . it should be appreciated that the following definitions are used throughout this application . the term “ insect ” includes any insect that is capable of displaying a consistent behavior in response to sensing a specific volatile or semi - volatile chemical . the term “ insect ” includes an insect that is trained or conditioned to display an observable behavior . the term “ insect ” includes an insect that displays the proboscis extension reflex ( per ). the term “ insect ” includes a honey bee . the terms “ sticky ” or “ stickiness ” refer to volatile or semi - volatile chemicals that have a tendency to adhere and collect on contacting surfaces or substrates . as shown in fig1 , two or more insects or bees 101 ( preferably five or more bees ) are placed and constrained in individual yokes 102 arranged in parallel such that the head of each bee is visible from at least one single vantage point within the instrument to allow for simultaneous observation of a per event . the yokes are fixed in a predetermined and patterned arrangement onto the base 103 of the holding tray 104 such that the fixed end of each yoke corresponds to the posterior end of each bee with the anterior ( head ) end of the bee pointed in the opposite direction away from the base of the holding tray . further , the heads of each bee are arranged such that they are substantially co - planar with each other and such that no other bee is placed either directly in front of or directly behind of another bee within the axis of air flow so that each bee receives its own portion of the air flow . however , it is not required that the bees are arranged linearly and are preferably arranged according to one embodiment in a non - linear array . the holding tray 104 is capable of being removably inserted into the device , and handling of the holding tray may be facilitated by the use of a knob 105 fixed to the outer surface 106 of the holding tray to become substantially flush with the outer casing ( not shown ) of the device when fully inserted . according to one aspect of the invention , five or more bees 101 are used to detect the presence of a volatile or semi - volatile chemical . using an increased number of bee detectors ( i . e ., bees ) allows for a statistically more accurate detection by reducing the number of false positives or negatives that might occur as a result of one or more errant bees . increasing the number of bees also allows for the additional implementation of control ( e . g ., untrained ) bees to make positive test events more reliable by helping to eliminate background effects that might contribute to a false event . fig2 a and fig2 b show one embodiment of the invention . the holding tray 104 is fully inserted into the housing 201 using the knob 105 attached to the outer surface 106 of the holding tray until the outer surface of the holding tray is substantially flush with the outer surface of the housing 201 and outer casing 202 of the device assembly 203 . once inserted , the bees are positioned inside the chamber 206 of the housing 201 . a latch or similar mechanism ( not shown ) may be attached to the inner surface of the holding tray 104 to allow the holding tray to remain stably fixed in place once it is fully inserted . the inlet 207 of the housing 201 is placed on the front portion 217 of the housing and is oriented to face outward and to be substantially flush with outer casing 202 of the device assembly 203 to allow for the air sample to enter the device from outside the device . the flow of air is generated by a fan ( not shown ) preferably positioned on the rear portion 218 of the housing 201 that is opposite the inlet 207 to generate a negative pressure that pulls the air through the device . in further reference to fig2 a and fig2 b , the upper portion 208 of the chamber of the housing creates an opening 209 to allow the per behavior of the bees to be observed . in an alternative embodiment , the opening 209 on the upper portion 208 of the chamber is covered with a transparent material . the present invention further includes a means for monitoring the insects . according to one embodiment , the monitoring means is preferably a camera 210 that is fixed to the upper portion 208 of the housing 201 such that the camera faces away from the position of the bees and uses a mirror 211 that is angled to put the bees in view of the camera . a light source ( not shown ) is also included in the chamber of the housing to allow the monitoring means to visualize the bees . preferably , the light source is placed near the base 103 of the holding tray 104 to provide a backlight for viewing the bees . the present invention further includes a means for focusing the camera preferably on the heads of the bees . the present invention includes a means for inputting commands to the device , which preferably comprises a keypad 212 . the present invention also includes an outputting means or readout 213 for displaying the results of a test . the keypad and readout are positioned so that they are substantially flush with the outer surface of the device casing 202 to allow the user to access the keypad and observe the readout . the present invention further includes a computer means 214 for processing the visual data to determine if a positive per event has occurred and directing the outputting means to communicate or display the results of a test in the appropriate format . finally , the present invention uses either a battery 215 or other power source to provide the necessary electricity to power the system , including namely the fan 303 , the optional pre - concentrating means 401 , the outputting 213 and inputting 212 means , the light source 304 , and the computer means 214 . finally , a carrying handle 216 is optionally included to allow the user to carry the instrument in a facilitated manner . fig3 provides a cross - sectional view of a preferred embodiment for the housing 201 . the air is first pulled into an inlet 207 on the front portion 217 of the housing and travels through a first channel 301 of the housing toward the chamber 206 where the bees are located . said first channel is approximately the width of the arrangement of bees in the chamber and is approximately co - planar with the arrangement of the heads of the bees . importantly , said first channel does not divide the air flowing to each bee detector but is instead substantially arranged as a horizontal slot , thus avoiding any unnecessary increase in surface area for the channel . in other words , said first channel creates one flow of air that is common to all of the bees . in addition , said first channel 301 is relatively short in length , thus placing the bees 101 closer to the inlet 207 and further reducing the surface area in contact with the air sample prior to exposure to the bees . the air sample is pulled into the housing 201 by a fan 303 that is preferably placed on the rear portion 218 of the housing generating an air flow that is substantially unidirectional and planar . thus , the air flow through the housing is substantially as follows : first , the air enters the inlet 207 on the front portion 217 of the housing . second , the air travels through a common first channel 301 that is relatively short . next , the air enters the chamber 206 in a substantially planar flow around the heads of the bees 101 . finally , the air exits the chamber and flows out of the housing through a second channel 302 and a fan 303 mounted on the rear portion 218 of the housing that pulls the air through it . the cross sectional view of the housing in fig3 further displays the preferred location for the light source 304 near the base 103 of the holding tray 104 to provide backlighting for the camera . the cross sectional view further shows the opening 209 on the upper portion 208 of the housing 201 that allows for the per behavior of the bees to be observed by the monitoring means or camera . in an alternative embodiment , the opening 209 on the upper portion 208 of the housing is covered by a transparent material . as depicted in fig4 , the present invention may optionally include a pre - concentrator assembly 401 . when engaged , the pre - concentrator includes a holder 402 that is mounted with the front surface 405 of said holder placed in front of the inlet 201 on the front portion of the housing 601 . said holder has a horizontal slot 403 of nearly identical size and dimension as said inlet 201 and said first channel 301 . the slot of said holder is attached to the housing such that said slot of the holder is placed directly in front of and is fully continuous with said inlet and said first channel . a metal strip or mesh 404 is removably placed over the rear surface 406 of the holder in contact with the entire opening of the slot and a portion of the holder . an insulating spacer 407 is placed between said metal strip or mesh 404 and said portion of the holder covered by said metal strip or mesh such that the spacer does not block any portion of the slot 403 or inlet 201 of said first channel to allow unimpeded air flow into the device . a sandwich assembly may thereby be formed by placing pieces 404 and 407 in alternating layers . further , the metal strip or mesh 404 is attached to an electrical source ( not shown ), and in one preferred embodiment , the metal strip or mesh 404 is composed of stainless steel . to operate the pre - concentrator , the air sample is passed over the metal strip or mesh 404 over a period of time to allow “ sticky ” volatile or semi - volatile compounds to adhere to said metal strip or mesh . once a sufficient or predetermined volume of air sample has been passed over the metal strip or mesh , said metal strip or mesh is attached to the pre - concentrator as described above ( if not already attached ), and a pulse of electrical current is introduced by an attached power source ( not shown ) to the metal strip or mesh at a predetermined level . the current introduced to said metal strip or mesh produces resistive heating i the metal that causes any “ sticky ” volatile or semi - volatile compounds that may have adhered to said metal strip or mesh to be released over a short period of time , thus increasing the concentration of the volatile or semi - volatile compounds presented to the bees during the pulse ( compared to concentrations present in the air ) to improve the probability that the bees will be able to detect and report the presence of sticky compounds that are present in the air sample at low concentrations . fig5 presents an alternative arrangement for the placement of the monitoring means or camera . although the arrangement of the housing , holding tray , etc . are identical in this alternative embodiment as described above , the camera 210 is placed directly above and in direct view of the bees . the camera is mounted onto a plate 502 that is designed to slide on the upper portion of a mounting bracket 501 with the bracket stem mounted on its lower portion to the housing . movement of the plate is along the major axis of the bracket 501 and is restricted by a tongue - in - groove mechanism that utilizes a projection 503 of the plate that tightly fits inside an indentation 504 of the bracket , thus allowing the camera and plate to slide only along a the major axis of the bracket ( i . e ., toward and away from the bees ). the adjustable movement of the plate and camera allows for the camera to focus on the plane of the heads of the bees . when the height of the camera and plate are at the appropriate height such that a focused image of the heads of the bees is created , the position of the camera and plate along the major axis of the bracket can be fixed in place by tightening a screw knob 505 . said screw knob has a screw portion ( not shown ) that goes through an opening 506 of the bracket with said opening oriented lengthwise along the major axis of said mounting bracket 501 preferably within said indentation 504 of the bracket . said screw portion of said screw knob also screws into the plate 502 on the opposite surface of the camera . this screw knob mechanism allows for the plate and camera to be fixed at a desired height along the major axis of the bracket when the screw knob is tightened . as shown in fig6 a , 6 b , and 6 c , the alternative arrangement in fig5 showing placement of the camera directly above the bees may be incorporated into an alternative type of device . all of the major components of the present invention are also provided in this alternative embodiment and function identically as described above , even though the relative placement of the holding tray 104 , keypad 212 , readout 213 in this alternative embodiment are repositioned . all documents , patents , journal articles and other materials cited in the present application are hereby incorporated by reference . although the present invention has been fully described in conjunction with several embodiments thereof with reference to the accompanying drawings , it is to be understood that various changes and modifications may be apparent to those skilled in the art . such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims , unless they depart therefrom . davis et al ., “ detection of odors using insects ,” ( u . s . pat . no . 7 , 237 , 504 ) issued jul . 3 , 2007 . bitterman , m . e ., “ classical conditioning of proboscis extension in honeybees ( apis mellifera ),” journal of comparative psychology , 97 ( 2 ), p . 107 - 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