U.S. patent number 3,706,877 [Application Number 05/107,140] was granted by the patent office on 1972-12-19 for densitometer having an analog computer for calculating a fraction of the total area under a curve.
This patent grant is currently assigned to Clifford Instruments, Inc.. Invention is credited to George F. Clifford, Jr., Robert C. Woodward.
United States Patent |
3,706,877 |
Clifford, Jr. , et
al. |
December 19, 1972 |
DENSITOMETER HAVING AN ANALOG COMPUTER FOR CALCULATING A FRACTION
OF THE TOTAL AREA UNDER A CURVE
Abstract
A densitometer which provides complete electrophoresis results
on a single sheet. An electrophoresis sample is scanned by a beam
of light energy. The light energy transmitted through the sample is
converted to an electrical signal. An analog trace of the density
profile is made on a recording chart. At the same time, the total
area under the curve is integrated. After the trace and integration
have been completed, the portions of the trace from which
additional information is required such as area percents and
protein levels are marked. The sample is rescanned and reintegrated
within the selected portions of the trace. The area percents and
protein levels are printed on the recording chart in digital form
when the rescanning of the selected portion of the trace has been
completed.
Inventors: |
Clifford, Jr.; George F.
(Natick, MA), Woodward; Robert C. (Natick, MA) |
Assignee: |
Clifford Instruments, Inc.
(Natick, MA)
|
Family
ID: |
26701999 |
Appl.
No.: |
05/107,140 |
Filed: |
January 18, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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27067 |
Apr 9, 1970 |
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Current U.S.
Class: |
702/137; 250/556;
235/61R; 346/13; 346/29; 346/30; 346/33A; 346/33F |
Current CPC
Class: |
G01N
27/44721 (20130101); G01N 21/5907 (20130101); G01N
21/27 (20130101); G01N 30/95 (20130101) |
Current International
Class: |
G01N
27/447 (20060101); G01N 21/25 (20060101); G01N
21/27 (20060101); G01N 21/59 (20060101); G01N
30/00 (20060101); G01N 30/95 (20060101); G01d
001/04 () |
Field of
Search: |
;346/13,30
;235/61.6R,61.6A,151.3 ;250/219QA,222R,222PC |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Botz; Eugene G.
Assistant Examiner: Dildine, Jr.; R. Stephen
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Ser. No. 27,067,
ELECTROPHORESIS DENSITOMETER MODEL 345, filed Apr. 9, 1970.
Claims
Having described our invention, what we now claim is:
1. A densitometer which comprises in combination:
a. a source of energy;
b. means to expose a sample to be analyzed to said energy;
c. means to cause the scanning of the sample by relative movement
between the sample and said energy;
d. means to convert the energy emerging from the sample to an
electrical signal;
e. means to display a selected signal in analog form;
f. means to integrate a selected signal;
g. means to select a portion of the analog form from which
additional information is desired;
h. means to cause the rescanning of the sample and to integrate the
signal received;
i. means to compare the integrated rescan signal with the
integrated scan signal; and
j. means to record the compared signals in digital form.
2. The densitometer of claim 1 wherein the source of energy is
light energy and which includes means to focus said light energy as
a beam, the means to expose the sample to the beam of light energy
includes an aperture therein whereby the sample may be placed on a
support means and the beam of light energy adapted to pass through
said aperture, and wherein the means to scan the sample includes
means to drive the support means along a predetermined path.
3. The densitometer of claim 2 wherein the support means includes a
holding means having a flat surface thereon, said surface being
characterized by a slot therein and being formed of a magnetizable
material, and further wherein a magnetic mat having an aperture
slit therein is secured to the flat surface of the holding means
whereby the sample is placed on the flat surface of the holding
means and the magnetic mat engages the magnetizable material
thereby holding the sample firmly in place.
4. The densitometer of claim 2 wherein the means to drive the
support means includes a motor means adapted to operate at a
selected constant speed which reciprocates the support means
between preselected positions.
5. The densitometer of claim 1 wherein the means to convert the
light energy to an electrical signal includes a photometer whereby
the energy is converted to current and said current is transmitted
to an amplifier whose output signal is voltage,
wherein the means to display in analog form includes a
servomechanism in combination with a recording stylus adapted to
trace a profile,
wherein the means to integrate includes a voltage-to-frequency
converter and a plurality of BCD cascade counters,
wherein the means to select portions of the profile trace to be
integrated on rescan includes means to mark a medium on which the
density profile trace is formed, and
which includes means to control the scan and rescan cycles.
6. The densitometer of claim 1 wherein the means to rescan the
sample includes holding means and drive means to move the holding
means along a predetermined path,
wherein the means to integrate the signal during rescan includes
means to accumulate a plurality of pulses on BCD cascade
counters,
wherein the means to compare the rescan signal with the total
accumulated signal includes means to calculate the percent of
rescan signals compared against the total accumulated signal,
and
wherein the means to record the signal in digital form includes
print means.
7. The densitometer of claim 6 wherein the means to calculate the
area percent includes a digital divider.
8. The densitometer of claim 1 wherein the sample being analyzed is
a thin layer chromatography plate.
9. The densitometer of claim 1 which includes means to define
preselected areas of the analog trace.
10. An improved densitometer which comprises in combination:
a. a source of light energy;
b. means to form a beam of said light energy;
c. means to expose a sample to be analyzed to the beam of light
energy;
d. means to scan the sample with the beam of light energy;
e. means to convert the light energy transmitted through the sample
to an electrical signal;
f. function generator means to convert the signal from the sample
to a level related to the amount of material to be analyzed in the
sample;
g. means to record the signal in analog form as a profile trace on
a recording medium;
h. means to integrate the selected signal with the recording of the
selected signal in analog form in communication with the function
generator means;
i. means to select a portion of the analog profile trace from which
additional information is desired;
j. means to rescan the sample and to integrate the signal
received;
k. means to compare the integrated rescan signal of the selected
portion of the analog profile trace with the total accumulated scan
signal whereby on comparison the pulses are discharged; and
l. means to record the compared signals in digital form on the
medium.
11. The densitometer of claim 10 wherein the function generator
means includes a linear inverse converter, a log inverse converter,
function of x converter, and further includes the means to record
in one of said functions and integrate in that or another of said
functions as desired,
wherein the medium includes chart recording means, and
wherein the means to record in digital form includes:
1. housing means,
2. bridge means secured to the housing means and extending across
the chart recording means,
3. sensing means adapted to indicate when the rescan of a selected
portion of the analog trace has been completed and pen means
disposed in the bridge means, and
wherein the chart recording means includes a chart which is
magnetically secured to a support means,
wherein the digital printing means are disposed within the housing
of the bridge assembly and axially aligned with and spaced apart
from the sensing means along the y axis of the recording chart.
12. The densitometer of claim 11 wherein the means to compare the
integrated rescan signal against the total accumulated scan signal
includes means to calculate percents.
13. The densitometer of claim 12 wherein the means to calculate
includes:
means to store a number representing the total amount of
material;
means to control the movement of the holding means and bridge
assembly means;
means to control the selection of the information transmitted to
the digital printing means in the bridge assembly means;
means to multiply percent times the total amount of material;
and
means to print the percent and the material amount for the selected
portion of the analog trace upon the receipt of a command from the
sensing means.
14. The densitometer of claim 10 wherein the sample being analyzed
is an electrophoresis strip.
15. The densitometer of claim 11 wherein the bridge assembly means
and the holding means for the sample are each driven by stepping
motors which stepping motors are driven by pulses derived from the
same pulse train.
16. A method of scanning a sample and recording the results of said
scan therefrom which comprises:
a. creating a source of light energy;
b. exposing a sample to be analyzed to the beam of light
energy;
c. receiving a portion of said beam of light energy emerging from
the sample on a receptor;
d. converting the light energy emerging from the sample to an
electrical signal;
e. integrating the electrical signal transmitted from the
receptor;
f. recording the signal from the receptor as an analog profile
trace on a medium;
g. selecting a portion of the profile trace from which desired
information is required;
h. rescanning and integrating the sample over the desired portion
from which information is desired;
i. comparing the integrated rescan signal against the total
integrated scan signal;
j. providing a value representative of a comparison between the
rescan signal against the total scan signal; and
k. recording said value in digital form on the medium.
17. The method of claim 16 which includes converting the light
energy emerging from the sample into an electrical signal by
transmitting said signal to a photometer;
integrating said signal by converting the signal to a plurality of
pulses and accumulating the pulses.
18. The method of claim 16 which includes recording the signal from
the photometer as an analog profile trace by tracing said signal on
a recording medium, and further which includes selecting the
desired portion of the profile trace from which additional
information is desired by marking the medium.
19. The method of claim 16 which includes converting the signal
received on rescan into pulses and totalizing the pulses received
and further which includes dividing digitally the pulses received
on rescan by the pulses previously accumulated during scan in a
digital divider.
20. The method of claim 16 which includes printing the calculated
value in digital form on the medium, and further which includes
storing a material amount level, multiplying the value times said
material amount level and recording said calculations in digital
form on the medium.
21. The method of claim 16 which includes:
transmitting the electrical signal to one of a plurality of
function generators,
selecting the function in which the analog trace is to be recorded,
and
selecting the function in which the integration is made.
22. The method of claim 21 wherein the function generators include
a log inverter, a linear inverter, and a function of x
converter.
23. The method of claim 16 wherein the sample to be analyzed is an
electrophoresis sample.
24. A modular computer for calculating a fraction of a total area
under a curve which comprises:
a. means to receive signals representative of variations in
composition of a scanned sample from a source;
b. means to display said signals in analog form;
c. means to integrate said signals;
d. means to select a portion of the analog form from which
additional information is desired;
e. means to receive and integrate signals representative of
variations in composition of the sample rescanned;
f. means to compare the integrated rescanned signal with the
integrated scanned signal; and
g. means to record the compared signals in digital form.
25. The computer of claim 24 wherein means to integrate the signals
received includes means to accumulate a plurality of pulses on BCD
cascade counters and wherein the means to compare the rescan signal
with the total accumulated scan signal includes means to calculate
the percent of rescan signals compared against the total
accumulated signal.
26. The computer of claim 24 wherein the means to display in analog
form includes a servomechanism in combination with a recording
stylus adapted to trace a profile, wherein the means to integrate
includes a voltage-to-frequency converter and a plurality of BCD
cascade counters, and wherein the means to select portions of the
profile trace includes means to mark a medium on which the analog
trace is formed.
27. The computer of claim 24 which includes:
a. function generator means to convert the signals received to a
level related to the amount of material to be analyzed in the
sample;
b. means to record the signals in analog form as a profile trace on
a recording medium;
c. means to integrate the selected signals with the recording of
the selected signals in analog form in communication with the
function generator means;
d. means to select a portion of the analog profile from which
additional information is desired;
e. means to compare the integrated rescan signals of the selected
portion of the analog profile trace with the total accumulated scan
signals whereby on comparison the pulses are discharged; and
f. means to record the compared signals in digital form on the
medium.
Description
BACKGROUND OF THE INVENTION
Zone electrophoresis has been used in clinical laboratories and
where used, there has always been a need to translate a
quantitation of an amount of material such as, for example, dye
stained protein to a report form.
Prior methods and equipment used for density determinations of the
dyed strip have been unsatisfactory for producing quick and
accurate laboratory results. For example, one method which has been
used involves cutting strips into different sections and then
eluting the dye from each of the sections. After extraction of the
dye, the optical density of the eluting solution is measured and
the resulting values are plotted on a curve as a function of the
distance along the original strip. It is clear that this method is
time-consuming and requires many laboratory operations. Another
method which has been used for this purpose is to saturate the
electrophoresis strip with an oil to make it more transparent. The
paper is passed over an illuminated slit and the amount of light
passed through the paper is measured by suitable electric means.
Again a curve is obtained as a function of distance along the paper
strip. This method has the disadvantage that any variation in
output of the light source leads to error in determination of the
density. Still another method currently employed, see for example,
U.S. Pat. No. 2,834,247, employs a mechanical ball and disc
integrator which traces a series of pips under the densitometric
trace. Each pip represents a defined amount of area under the
densitometer profile. The operator then determines where components
started and stopped, counts the pips under each peak, totals all
the pips, and then calculates an area percent value. A further
method employed is to use an electronic voltage-to-frequency
converter to activate solenoids which draw area pips under the
curve trace. A still further method used is to scan the
electrophoresis pattern repetitively sensing the transmitted light
and projecting the density profile on a cathode ray tube. The
operator adjusts the base line, sets gates to cause a total area
integral of the pattern, and adjusts a meter to read 100. The
integration gates are set for individual peaks and the operator
reads the area value from the meter. However, with this method no
record is made of the decision by the operator on which valleys
were selected for the particular area percents. All of the above
methods each have distinct disadvantages either by being too
time-consuming or too inaccurate and further requiring translation
of results to a final report form.
SUMMARY OF THE INVENTION
We have developed a unique apparatus and method whereby complete
electrophoresis results can be provided on a single form and which
apparatus and method eliminates the necessity of the manual
recording of data. In our invention the electrophoresis strip
material is scanned and the light transmitted through the sample is
received by a photometer. This transmitted signal is generally
directly proportional to the amount of the light transmitted
through the electrophoresis strip. An analog trace of the pattern
is recorded on a chart. At the same time the profile is being
recorded, the area under the profile is integrated and this value
is stored. The operator through marking the chart on which the
profile is recorded selects portions of the profile from which
portions the material amount levels and area percents are to be
determined. The total material in the sample say for example, the
total amount of protein, is stored in a calculation system in the
densitometer through a digital dial. The pattern is rescanned and
where the markings the operator has made are detected, the area
percents and material levels are printed in digital form directly
on the chart. After rescan, the operator on one chart or sheet has
all the information that is required in final form.
Briefly, our invention comprises a source of radiant energy (wave
or particle) such as light energy which may be ultraviolet,
infrared, white, and of any wave length which light energy is
formed into a beam, such as by passage through a lens system and
then focused on the sample and limited as by passage through a
slit. The sample to be analyzed which may be transparent,
translucent or a semiopaque material containing material to be
analyzed quantitatively or qualitatively, which permits variations
in passage of the energy through the sample to aid in sample
analysis. For example, an electrophoresis strip is exposed to a
beam of light energy which may be employed in the sample by
reflectance, transmission, fluorescence, or quenching; that is,
through an absorbtion of light. The light emerging from the sample
is received on a suitable receptor such as a photometer, for
example a photocell, photomultiplier, photo-diode, etc., where the
signal is converted to an electrical signal. This electrical signal
is then transmitted to a function generator which converts the
signal from the sample to a level linearly related to the amount of
material to be analyzed in the sample. The conversion of the signal
from the light receiving means may be linear, logarithmic, log
inverse, linear inverse, or some other hybrid function. Other types
of samples which themselves provide a source of radiant energy may
be successfully used with the invention in which a separate source
of energy is not required, such as radioactive samples. For
example, materials such as proteins may be tagged with radioactive
particles in which case the tagged material itself is the energy
source and the slit needs only to reflect or absorb a radioactive
material whereby the photomultiplier is only looking at one section
of the pattern at any given time. This technique may also be
employed with tagged amino acids.
After passing through the function generator, the signal is
recorded in the function desired as a profile trace.
Simultaneously, with the recording of the profile trace, the signal
is converted to a pulse train the frequency of which is related to
the signal level and the pulses are accumulated and stored thereby
integrating the area under the profile trace. After the density
profile has been traced and the area under the profile integrated,
a portion of the trace profile from which additional information is
desired, such as the particular area between selected portions, is
then marked. The sample is rescanned over the portion scanned
previously. The integrated rescan signal is then compared with the
accumulated scan signal, the values compared, and the area percents
computed as well as the material amounts. Upon command, the desired
information is then recorded directly on a medium such as a
chart.
Other distinct advantages of our invention are the ability to
record the density profile in one function, say for example in
linear inverse, and to integrate in another function, say for
example log inverse; or to record the trace profile and integrate
in the same function. Also, because the printing of the information
on rescan is on the same recording form as the indications made by
the operator, all pertinent information is directly printed out on
the same report form.
Because the majority of clinical laboratories are involved in
programs leading to the use of computers for compiling laboratory
results by patient, computer compatibility has also been designed
into the densitometer. The area percent information and the percent
protein values are both held in binary coded decimal (BCD) form. On
receiving a pulse from the computer, the information can be
transferred to the computer and thence to a memory block to be held
until the computer calls for the information on that patient. A
minimum of computer memory is required since the need for
point-by-point logging of the density profile is completely
eliminated.
Further, since the densitometer has its own calculation capability
it does not depend upon a computer to derive area percents or
percent material values, complete results are obtainable whether or
not the computer is in service. Inspection of the chart containing
the density profile provides immediate information such as to the
identification of albumin and the various globulins. In providing a
means for locating fractions along the density profile, the pattern
being scanned, the sample, and the recorder are both driven with
stepping motors. By counting the steps to each valley, location
information is provided which can be used in a simple computer
program to identify fractions.
Since most cellulose acetate and gel patterns can be precisely
quantitated by integrating in log inverse, this is generally the
preferred embodiment or method of operation in the densitometer.
However, if the amount of light absorbing material does not
increase linearly with optical density, the densitometer is also
provided with means to perform the integration linearly in a
function such as dye concentration on filter paper or such other
function as defined by the user.
In our invention, the analog system of a densitometer has been
combined with the digital calculation and printing capabilities of
a digital computer to provide on a single report a density profile
of the electrophoresis pattern, marks such as by punches or from an
electronic valley sensing system indicating how the pattern was
divided for calculation purposes, a digital value of area percent
printed on the chart for each peak or group of peaks in the
pattern, means to enter the total amount of sample material into
the densitometer and to print that amount of digital form on the
chart, and the capability to multiply area percent times the total
material and to print the amount of each fraction selected. Our
invention eliminates the necessity of meter reading and
interpolation errors as well as transcription errors and combines
an analog and digital presentation for obtaining the greater
precision of the digital system for calculation of results and
further, it is not limited to a certain number of peaks by number
of analog memory devices. The marking system employed is
advantageous in that it obtains correct results from all serum
protein and lipoprotein patterns which often have shoulders and
points of inflection which cause an electronic valley sensor to
divide patterns into fractions which are not related to the actual
material distribution desired.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the instrument;
FIG. 2 is a block diagram of the basic sections of the
instrument;
FIG. 3 is a partly schematic and partly sectional view of the
optical system of the invention;
FIGS. 4a and b are plan views of the sample holder;
FIG. 5 is a schematic illustration of the amplifier and signal
conditioning, mode selection, and integrator and scaler portions of
the invention;
FIG. 6 is a schematic illustration of the digital printing drive
system of the invention;
FIG. 7 is a partly block diagram and plan view of the control
section of the invention;
FIG. 8 is a plan view of the analog pen recorder section of the
invention;
FIGS. 9a and b are schematic illustrations of the movement of the
bridge assembly during the slew, scan, pretravel and rescan
cycles;
FIG. 10 is a plan view of the valley sensing system;
FIG. 11 is a block diagram of the functional elements of the
invention;
FIG. 12 is a circuit diagram of the print control;
FIG. 13 is a circuit diagram of the unit control;
FIG. 14 is a diagram of the pretravel circuit; and
FIG. 15 is a circuit diagram of the up-down counter.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
The instrument 10 is shown in FIG. 1 and includes two consoles 12
and 14. The entire system is also shown in block diagram form in
FIG. 2. Each major section of the system will be described
individually prior to the description of the entire system in a
working embodiment.
OPTICAL SYSTEM
The optical system is shown in greater detail in FIG. 3 and
comprises a white light source 22 which is powered by a regulated
power supply 24. The light source as shown is a standard lamp
operated at a fixed temperature of about 2,700.degree.K. If desired
to ensure that the light intensity is constant, a receptor 25 shown
in the dotted lines may be utilized to regulate the power supply
based on the intensity of the light received. Light energy from the
source passes through a heat absorbing or reflecting lens 26,
condensing lens 28, filter 30, deflects off a mirror 32 and then
passes through an aperture 34.
If desired depending upon the sample being analyzed, energy sources
other than white light may be used such as ultraviolet, infrared,
etc., and the wave lengths of the incident energy may vary as
selected by filters, monochromators, or lenses used. Further, light
energy may be measured emerging from the sample by reflectance,
transmission, fluorescence, or quenching.
Referring to FIGS. 3, 4a and b, an electrophoresis sample 36 is
placed in a unique holder 37 which employs a flexible magnetic mat
38 such as vinyl ferrite in combination with a magnetizable
material 40 such as steel. The holder communicates with a stepping
motor 44, which reciprocates the holder along a fixed path during
the scan and rescan cycles. The stepping motor also communicates
with the unit control 80 as shown in FIGS. 7, 11, and 13. The use
of the magnetic mat to hold the sample in place facilitates
insertion and adjustment of the sample in the holder while firmly
holding the sample in place during the scanning and rescanning
cycles. A termination switch 46 which can be adjusted to coincide
with one end of the portion of the sample to be scanned, terminates
movement of the sample holder at the end of the scan cycle.
A photocell 48 such as a vacuum photodiode receives the light
transmitted through the sample and converts the signal to a current
proportional to the energy emerging from the sample being
analyzed.
INTEGRATION
Referring now to FIG. 5, the current from the photocell 48 of FIG.
3 is transmitted to an amplifier 50 such as a variable gain
amplifier. One of a plurality of function generators such as a log
inverter 52, linear inverter 54, or a hybrid function 55, receives
the signal from the amplifier 50 and transmits the signal at a
different level to an analog recorder 56, such as a servoamplifier.
Simultaneously the signal is also transmitted to a
voltage-to-frequency converter 57. As shown, if desired, a signal
may be transmitted directly rather than passing through one of the
function generators. A plurality of cascaded binary-coded decimal
decade counters within the total pattern integrator 58 or total
area counter accumulate, totalize, and store the pulses received
from the voltage-to-frequency converter 57 whereby the total area
under the density profile trace on the recording chart as shown on
FIG. 8 is integrated. Upon rescan, certain selected portions of the
density profile trace are selected for analysis and the sample
rescanned whereby the area under the selected portion is
reintegrated, and the pulses accumulated in the peak integrator 59
or rescan counter. These rescan pulses are compared in the
comparator 60 against the pulses stored in the total pattern
integrator 58. The total pulses in the total area counter are
digitally divided by 1000 to provide units or values of comparison
of 0.1 percent of the total area under the curve. When the rescan
pulses reach a predetermined level corresponding to 0.1 percent of
the total area, the information is transmitted to the digital
printing and drive system shown in FIGS. 6 and 12. After each
transmittal of 0.1 percent pulses to the data selectors, the
comparator resets the rescan counter 59 and the pulses are again
accumulated until they reach a value of 0.1 percent of the total
area as determined by the comparator. Again the information is
transmitted to the data selectors. This cycle continues throughout
rescan while periodically the valley sensing system will command
the printing and drive system to print the desired information as
will be described later.
As shown in FIG. 7 and FIG. 5, the operator may integrate in one
function such as log inverse, and record in another function such
as linear inverse, during a scanning cycle, or if desired, through
the selection of the appropriate functions the integration and
recording may both be accomplished in the same function or either
function may be accomplished directly.
DIGITAL PRINTING AND DRIVE SYSTEM
Referring to FIGS. 6 and 11, the digital printing and drive system
comprises a plurality of data selector circuits 62a, b, and c which
communicate with a plurality of print adapters 64a and b which
transmit the signal received from the data selectors to the count
wheels and actuate the count wheels in the recording system. A
material multiplier 66 or milligram adapter which comprises a
binary coded circuit stores the total amount of protein which value
is inserted into the multiplier by the operator through the digital
dial 78 shown in FIGS. 7 and 11. The 0.1 percent signals from the
comparator flow in two directions, one directly to the data
selectors in combination with the print adapter 64a, and the second
to the milligram adapter 66 and then to the data selectors
associated with print adapters 64b. The material multiplier
digitally multiplies the percent signal times the total material
value as dialed-in prior to transmittal to the data selectors.
As will be described in detail, upon receipt of a command from the
pretravel circuit shown in FIG, 14, the stored value of total
material is printed on the recording chart prior to rescan. Upon
receipt of a command from the valley sensing system, the area
percent and the area percent times total material corresponding to
the selected portion of the chart is printed on the chart.
The print control circuit 68 is adapted to receive commands from
the unit control 80 shown in FIG. 7 and the valley sensing system
101 shown in FIGS. 11, 12, and 13.
UNIT CONTROL
Referring to FIGS. 7, 11, and 13, the unit control 80 comprises a
control panel 70 having a series of switches for commencing
operation of the instrument and as shown includes the reset, scan
and rescan switches and valley selection indicator. An integrator
dial 72 and recorder dial 74 select the recording and integration
functions as was described for FIG. 5. Also on the front panel, is
a scan length switch 76 which determines the ratio of the speed of
motion of the pattern to the speed of motion of the bridge in the
recorder. This speed ratio controls the amount of total motion of
the pattern which corresponds to the bridge moving across the
usable portion of the chart, and the scan length switch is
calibrated in these distances.
In communication with the control panel is the unit control 80 also
shown in greater detail in FIG. 13. A pulse generator 82 which is
disposed in the print control 68 communicates with the unit control
80 and provides a pulse train for driving both the stepping motors
44 and 90 shown as drives in FIG. 11 for the scanner and recorder
respectively. To ensure that the movement of the bridge carrying
the pen, and the holder carrying the sample being scanned each move
precisely the same distance during scan and rescan, an up-down
counter 84 counts the pulses generated during scan and rescan to
terminate the rescan mode when the same section of the pattern
originally scanned has been rescanned. This ensures that the total
area integrated is identical in both scans.
A slew switch 83 moves the recording pen to the starting position
prior to the actuation of the scan cycle. A pretravel circuit 86 on
rescan moves the bridge carrying the pen recorder, count wheels,
and valley sensing system, a predetermined distance prior to
actuating rescan of the sample to compensate for a mechanical
offset of the pen 98 and valley sensing system 101. This circuit
also controls the print-out of the total amount of material which
is stored in the material multiplier.
RECORDING SYSTEM
Referring to FIGS. 8 and 9a and b, the analog pen recorder
comprises a bridge assembly 92 which includes two sets of count
wheels 94 and 96 which communicate with the print adapters 64a and
64b which wheels record the area percent of selected portions of
the density profile trace and the material protein levels. A pen
recorder 98 engages a recording chart 100. The trace of the pen
along its x axis is controlled by the movement of the bridge driven
by the stepping motor 90. The amplitude or movement of the pen
along the y axis is controlled by the analog recorder whereby the
pen position is directly proportional to the signal selected for
recording. The recording pen 98 is slidably engaged within the arm
102 of the bridge assembly 92.
A valley sensing system 101 as shown in FIG. 10 comprises a light
source 104 and a photoresistor 106 disposed within the arm which
source and resistor are located on either side of the recording
chart 100. When actuated on rescan, the valley sensing system
senses the marks made in the recording chart by the operator and
transmits a signal to the digital printing drive system. If
desired, in lieu of the light and photoresistor, other valley
sensing systems such as an electronic valley sensing system may be
used.
FIG. 8 is a top plan view of the travelling bridge and recording
chart after scan and rescan. A stepping motor 90 which is
preferably driven by the same pulse train as the scanner stepping
motor 44 moves the bridge assembly 92 along a fixed path during the
scan and rescan periods of travel. The line of digits 112 represent
area percent and the line of digits 114 represent the material
level accumulated to each mark on the recording chart.
The recording chart 100 is carried in a unique holder 124. Each end
of the recording chart is magnetically held down by magnetic strips
116 which overlay the chart and magnetically engage the steel
surface of the holder.
THE OPERATION
The operation of our invention will be described in reference to an
analysis of an electrophoresis strip in which various protein
fractions of a blood sample are distributed along the strip.
Initially the power of the instrument is activated. Referring to
FIGS. 4a and b, a sample 36 is placed on the steel holder 40 and
the magnetic mat is placed over the sample and magnetically secured
to the steel plate 40. The slit 34 through which the light energy
passes is adjusted to the desired width. The termination switch 46
shown both in FIGS 4a and b and FIG. 3 is then set manually to
limit the movement of the sample being scanned during the scanning
cycle and generally is located about at the end of the protein
pattern. The sample holder is adjusted until the slit is under a
clear portion of the pattern wherein a maximum amount of
transmission of light is passing therethrough. The light energy
created by the lamp passes through the various filters and lenses
is focused on the pattern and passes through the adjustable slit 34
and received on the phototube 48 which communicates with the
amplifier 50. The variable gain amplifier 50 is adjusted until the
pulses received on the voltage-to-frequency converter are as close
to zero as possible. This may be determined by visual electrical
means such as a flashing lamp 16 which is shown on the console 14
in FIG. 1 and in FIG. 11. The termination switch for the bridge
assembly (not shown) may also be adjusted to limit the movement of
the bridge during scan.
A recording chart 100 is secured across a flat surface as shown in
FIG. 8 by magnetically engaging the edge of the paper to a holder
through the use of a magnetic strip 116 which cooperates with the
magnetic holder along the edge of the flat surface.
The function in which the trace is made and in which the area under
the profile is integrated is then made. As shown both the
integration and the profile trace will be done in log inverse
functions. On the recording switch it is possible to vary the
amplitude of the trace pattern at a ratio of two to one by
selecting the 1.5 or the 3.0 optical density (O.D.) level. That is,
if the log inverse function is directed to the 3.0 O.D. level, then
the amplitude of the trace on the recording chart will be half than
that if the selection had been at the 1.5 O.D. level.
Of course, it should be understood that, if desired, recording in
linear inverse would expand the small peaks making it possible for
the operator to make better decisions on the proper selection of
valleys between peaks while integration may be performed in a log
inverse function to correctly quantify material.
Referring to FIG. 7, the scan length selection switch 76 is set to
determine the length of the scan of the trace of the pen in
reference to the scan of the sample. The scan length determines the
ratio of speeds of the bridge assembly to the sample holder. That
is, as shown, it is set at 50 which means that the speed at which
the bridge assembly is driven will be four times the speed at which
the sample moves from its initial position until the scan cycle is
stopped by actuation of the termination switch 46. The length of
the scan of the sample is determined by the location of the
termination switch after the sample has been inserted in the
holder. The length of the trace across the chart along the x axis
is determined by the scan length control which is dependent upon
the ratio of speeds between the stepping motor driving the sample
scanner and stepping motor driving the bridge assembly. The
termination switch 46 for the bridge assembly may be employed in
lieu of the termination switch 44.
The amount of material in a particular sample which in this
instance is the total amount of protein in the sample is then
dialed in the digital dial manually 78 and stored in the milligram
adapter as shown in FIG. 6. Referring to FIG. 13, if the reset lamp
is not on, the reset switch (lamp switch) also shown on the control
panel 70 in FIG. 7 is actuated and sets flip-flop 115a to the one
state via gate 111c. This energizes the reset lamp on the control
panel 70 and holds the instrument in the reset mode. The slew
switch 83 is actuated to move the bridge assembly into position as
shown in FIG. 9a through the slew distance. The zero potentiometer
connected with the amplifier 50 is adjusted to bring the light 16
to a flashing condition. Also, when the rescan switch is actuated,
all stages of the up-down counter 84 shown in FIG. 15 are set to
"0" by gates 511a and 511b.
When the slew switch 83 is actuated, the bridge assembly or
recorder moves the slew distance A as shown in FIG. 9. Referring to
FIG. 13, gate 211a is enabled by the actuation by the slew switch
83 on the control panel to manually position the recording assembly
to the right as shown in FIG. 9a.
The scan switch on the control panel 70 is then actuated and since
the switches on the control panel are light switches, the actuation
of the switch is indicated by the light as shown in FIG. 13.
Actuation of the scan switch on the control panel after the bridge
assembly has moved its "slew" distance with flip-flop 115a in the
one state sets flip-flop 115b to its one state and resets flip-flop
115a to its zero state through gate 112a. Flip-flop 115b enables
flip-flop 116a to be set to its one state through gate 112b
immediately after flip-flop 115b has been set. The output of gate
112b also resets flip-flop 115b through gates 111d and 113a. When
either flip-flops 115b or 116a are in the one state the scan lamp
is energized via gate 113d. Flip-flop 116a thus holds the
instrument in the scan mode until it is reset by a signal from the
scanner termination switch 46.
The logic level generated by gate 211a controls the direction of
rotation of the stepping motor 90 to drive the bridge assembly. The
bridge assembly stepping motor drive signal which is a 10Ms square
wave is obtained from gate 211d. The logic levels generated by
gates 211a and 210c control the direction of rotation of the
stepping motor 90 via logic circuitry in the stepping motor drive
unit. The motor drive signal is derived from the square wave clock
located in the print control unit through gates 211b or 211c.
During the scan cycle, gate 211b is enabled through gate 211a by
flip-flop 116a which is in its one state. Gate 211a generates a "go
right" command. As shown in FIG. 9a, this would move the bridge
assembly to the right through its scan cycle.
The scanner drive motor or stepping motor 44 is controlled in
similar fashion when the instrument is in the scan mode. Flip-flop
116a commands the scanner holding the sample to "go right" during
the scan mode (flip-flop 117b commands the scanner to "go left"
during the rescan mode) via logic circuits the same as those
employed for the bridge assembly stepping motor drive and generally
located in the stepping motor drive unit 44. The period of the
scanner motor drive pulses 44 is manually selectable in order to
provide three scan langths: 25 centimeters, 50 centimeters, and 100
centimeters as shown in FIG. 7. The scan length switch 76 on the
control panel and as shown in FIG. 13 selects gates 213a, 213b, or
213c (via inverters 212b, 212c, and 212d) for the appropriate
scanner motor drive signal. The three available signals are derived
from the 10Ms clock and the outputs of the two-stage counter
flip-flop 118a and flip-flop 118b which provides square waves of
20Ms and 40Ms. The outputs of gates 213a, 213b, and 213c are
applied to gate 214d which during the scan cycle is enabled by
flip-flop 116a. (During the rescan cycle, gate 214d is enabled by
flip-flop 117b.)
When the scan switch is actuated, the stepping motors 44 and 90 are
driven by the pulse generator 82 whereby the stepping motors move
the scanner holder 40 transversely to the beam of light passing
through the slit 34 and move the bridge assembly 92 along the x
axis of the recording chart 100. The variations in light
transmitted through the sample are received by the photometer 48
and transmitted to the amplifier 50. The signal is converted to a
selected integrator function log inverse as shown and
simultaneously converted to a selected analog recorder function,
log inverse as shown. The density profile trace of the sample being
scanned is recorded on the recording chart 100 by the pen recorder
98. The pulses from the voltage-to-frequency converter are serially
accumulated in the cascaded binary coded decimal counters in the
total pattern integrator 58 and totalized while the sample is being
scanned. When the sample holder 40 actuates the termination switch
46, a signal is transmitted to the unit control 80.
During the scan cycle, 40Ms clock pulses are applied to the up-down
counter 84 and during this cycle flip-flop 116a commands the
up-down counter 84 to count up. The pulses during scan are
accumulated to some arbitrary count depending upon the scan period.
Referring to FIG. 15, flip-flop 116a of unit control through gates
214a and 214b enables gate 512b and gate 512a is disabled via gates
501a and 501b respectively. When flip-flop 513a responsive to 40Ms
pulses from the unit control changes from its "1" to its "0" state,
a carry pulse is transmitted through gates 512b and 512c to the
input of flip-flop 513b. In a like manner each of the nine stages
as shown receives an input pulse from the preceding stage when the
latter goes from "1" to "0". This results in an up-counting mode.
Also, during the scan cycle, the pretravel counter 86 receives 40Ms
pulses from gate 214c which is enabled by flip-flop 417a.
Referring to FIG. 13, the termination switch 46 signals through
gates 112c, 113b, and 113c that the scanner has reached the end of
travel in the scan direction. The output of gate 112c sets
flip-flop 116b to its one state and thus establishes the select
valleys mode and terminates the scan mode. Although the scanner
limitation or termination switch has been shown, a similar
termination switch which may be physically adjusted to limit the
travel of the bridge assembly rather than the scanner may be
employed in this instrument which bridge assembly termination
switch would be responsive to engagement by any desired portion of
the bridge assembly. As shown in FIG. 13, the termination switch
(recorder or scanner) is designed so that a switch may be employed
as shown for the scanner or for the bridge assembly or for both and
the unit control would be responsive to the first received signal.
The output of gate 112c also sets flip-flop 116b to its one state
which establishes the select valley mode and resets flip-flop
116a.
The select valleys indicator or light on the control panel is
actuated and the operator at this time selects the valleys on the
profile trace between which valleys the area percent and protein
levels are to be determined. As shown in FIG. 8, these valleys are
selected by physically punching slots in the edge of the recording
chart 100. The select valleys lamp is controlled by flip-flop
116b.
The pretravel counter 86 which is shown in schematic form in FIG.
14 is preset to a determined number (determined during final tests)
via gates 419a and 419b by a signal from the unit control when the
select valleys switch is actuated. The preset number is determined
by wiring jumpers to the terminals as shown. During rescan 1 or
pretravel, clock pulses from the unit control are applied to the
input of the counter. The counter is wired to count down from the
preset number. At the count of 010000 (i.e., decimal 2) gate 412
generates the command which causes the value of the material amount
level which was stored by the digi-switch to be printed on the
recording chart. At the count of 1000000 (decimal 1) gate 411
generates the end of pretravel signal which signal initiates the
rescan 2 mode and terminates the pretravel or rescan 1 mode.
After the indications have been made on the recording chart 100
selecting the valleys to be examined, the rescan switch is actuated
whereby flip-flop 117a is set to its one state via gate 112d. The
actuation also resets flip-flop 116b to its zero state. Flip-flop
117a establishes the pretravel or rescan 1 mode. Referring to FIG.
9b, this moves the bridge assembly 101 the pretravel distance C
while the scanner remains stationary. That is, the stepping motor
90 drives the bridge assembly. The pretravel counter which
previously received pulses from gate 214c which was enabled by
flip-flop 117a is designed to count down a predetermined number of
pulses during this pretravel cycle to control the movement of the
bridge assembly the distance C shown in FIG. 9b. As previously
described, flip-flop 215 is set to its one state by flip-flop 117a
which causes gate 210c to generate a "go left" command and also
enables gate 211c to provide the motor drive pulses. When the
rescan switch is actuated, the print control 68 receives print
commands from the pretravel counter 86, for example, the total
material amount in the total material digi-dial 78 upon command
from the pretravel counter, the value stored in the digi-dial 78 is
transferred to the decade counters in the data selectors 62a, b,
and c in combination with the print adapter 64b. The command from
the pretravel counter enables gate 312a of FIG. 12 to trigger the
circuitry which transfers the data to be printed from the data
selectors to the print adapters. Flip-flop 310a enables gate 306b
to transmit print pulses to the printer adapters to the count
wheels, and then to the printer solenoid command at the appropriate
time. This particular circuitry will be described in detail during
the rescan 2 cycle of the instrument.
The amount of material in the digi-dial is printed as shown on FIG.
8 by the count wheels 96. Upon completion of the pretravel cycle
when the pretravel counter has counted down to zero or decimal one,
a signal from gate 411, FIG. 14, is gated to gate 212a of the unit
control. This sets F/F 117b to its one state and causes the scanner
motor drive to generate a "go left" command. Also, through gates
214a and 214b it causes the up-down counter 82 to count down at the
termination of the pretravel. The bridge assembly continues to move
and the updown counter commences to count down and simultaneously
the stepping motor 44 is actuated and the sample rescanned and
curve reintegrated as described during the scanning cycle.
Referring to FIG. 15, gate 512a is enabled from gate 214b and gate
512b is disabled whereby flip-flop 513b receives an input pulse
when F/F 513a goes from "0" to "1" and similarly for other stages.
In this mode the counter counts down from the count which was
accumulated in scan. When the count reaches zero, gate 515 produces
an output to the unit control to gates 111a, 111b, and 111c which
sets flip-flop 115a to "one," its reset condition, and resets
flip-flop 117b to its zero state to terminate the drive of the
stepping motor 44 and to end rescan two. This stops scanning motor
44 and reintegration of the sample. The bridge assembly continues
moving the distance E shown in FIG. 9b until it strikes the "left"
termination switch after moving the slew distance.
On rescan, the pulses received on reintegration are transmitted to
the rescan counter and accumulated. Referring to FIG. 11, the
pulses from the voltage-to-frequency converter received on rescan
are accumulated in the rescan counter 59. These pulses are
continuously accumulated and compared in the comparator 60 against
the total accumulated pulses and in total area counter 58. The
pulses initially received in the total area counter are divided by
1,000 to produce 0.1 percent pulse values. Each time the rescan
counter 59 counts pulses corresponding to 0.1 percent pulses as
determined by the comparator 60 this information is transmitted
directly to the decade counters in the data selectors 62a, 62b, and
62c.
As shown most clearly in FIG. 11, the pulses are serially
accumulated in the decade counters of the print modules directly
from the comparator. The same signal or value from the comparator
each time the 0.1 percent pulse level is reached is transferred
directly to the milligram adapter 66. The milligram adapter
multiplies the percentage of each signal received by the total
amount of protein which was dialed in by the digi-dial 78 and
serially transfers this information to the decade counters
associated with the data selectors of the material print modules.
After each transfer of the 0.1 percent pulse to the appropriate
data selectors, the rescan counter is automatically reset by the
comparator. In the rescan mode the transfer of information to the
data selectors continues and is accumulated in both sets of the
decade counters until such time as the first mark made on the
recording chart 100 is sensed by the photocell of the valley
sensing system. When the photocell 106 in the valley sensing system
which is contained within the arm of the bridge assembly 92 senses
the first mark by the operator, the information is printed directly
on the recording chart 100 by the count wheels 94 and 96.
Referring to FIG. 12, the signal from the photocell which senses
the mark which was punched by the operator to select the valleys is
applied to amplifier A8. When the punch mark is sent, the output of
A8 sets flip-flop 310a to its one state via gates 308, 301a, 302c
and 302d. Gates 312a and 312b as shown form a pulse-shaping
network. The output of gate 302d also enables the gate 312a to
trigger the circuitry which transfers data to be printed from the
data selectors to the print adapters. This circuitry which
comprises flip-flops 316a, 316b, and gates 312a, 312b, 312c, 311c,
311d, 306a, 315a, 315b, and 315c develops a 0.4 microsecond
transfer command to the data selectors followed by a 0.4
microsecond clear command. The data input lines to the data
selectors are inhibited during the clear and transfer period.
Referring to FIG. 11, when the output from gate 302d enables gate
312a to trigger the circuitry as described, referring to the data
selectors 62a, 62b, and 62c, the information accumulated in the
decade counters is allowed to pass through the transfer gates and
into the binary coded decimal to serial converters which comprise
the print adapters. Specifically, for the 0.1 percent pulses
transmitted directly to the percent print modules, the information
accumulated on the decade counters flows through the transfer gates
and into the serial converters or print adapters 64a. Similarly,
the same occurence takes place at print adapters 64b where the
information which was multiplied in the milligram adapter and
accumulated on the decade counters in transferred to the serial
converters of the print adapters 64b.
Flip-flop 310a enables gate 306b to transmit print pulses to the
print adapters. Flip-flop 310a also enables gate 314a to transmit
clock pulses to the input of a five-stage counter which comprises
flip-flops 305a, 305b, 309a, 309b, and 310b. The fivestage counter
controls the time interval during which the print pulses and reset
pulses are applied to the print adapters. This counter also
generates the print or solenoid command at the appropriate time. In
the select valleys mode reset pulses are generated on command from
the unit control via gate 314d. At the conclusion of the print
cycle, flip-flop 316a, 316b and 310a are reset to zero by a signal
from gate 313 through gates 315d, 315e, and 315f. Flip-flop 310a
then resets the five-stage counter. The print control is then ready
to receive the next command. During the rescan mode, the print
commands from the valley sense circuit are accepted only during
this mode and this feature is controlled by gate 308. The print
command output code is a two-bit code generated by gates 311a and
311b. Therefore, gate 306b in timed relationship transmits print
pulses to the print adapters 64a and 64b. This information is
transferred to the count wheels where the count wheels are rotated
to the proper position. Subsequently, upon command from the
counter, the print or solenoid command is made whereby the
information is printed in digital form on the recording chart 100
as shown in FIG. 8.
This rescan mode is continued and each time the valley sensing
system senses the mark made by the operator, the accumulated
information in the decade counters is transferred to the print
adapters and then printed on the recording chart. The rescan and
reintegration of the sample and the movement of the bridge assembly
is continued until the movement of the scanner drive ceases when
the counter 84 has counted down. The bridge continues travel on
rescan whereby a left recorder limit switch (not shown), which is
physically set to engage the bridge assembly at the end of the slew
distance, resets flip-flop 215 comprised of gates 215a and 215b.
This in turn inhibits the recorder motor drive pulses through gates
215c, 215d, 210c, 211c, and 211d. The recorder stepping motor drive
signal which is a 10Ms square wave is obtained from gate 211d. As
mentioned above, in the rescan mode flip-flop 215 of the unit
control is set to its one state by flip-flop 117a. This causes gate
210c to generate a "go left" command and also enables gate 211c to
provide the motor drive pulses.
Similarly, the scanner drive stepping motor 44 is controlled in
similar fashion. Flip-flop 117b commands the scanner to "go left"
during the rescan mode via the logic circuits located in the
stepping motor drive unit 44. Referring to FIG. 9b, the bridge
assembly is now in the position indicated by the dotted line and
prior to analyzing the next sample, the slew switch is actuated to
bring the bridge assembly and pen back to the beginning of the scan
cycle.
* * * * *