Note: Descriptions are shown in the official language in which they were submitted.
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~: Background of the Invention
-: 1. Field of Invention:
The present invention relates to processes and devices
for determining rheological properties of biological and other
liquids. More specifically~ the present invention is directed to-
, wards processes and devices for obtaining bodily mucus, chiefly
cervical mucus and/or oral mucus, and for determining its viscoelastic
` properties in order to predict and indicate the inception and the
presence of ovulation for conception control.
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2. Description of the Prior Art:
It has been found that mucus samples from the vaginal and
oral cavities undergo distinct in-phase rheological changes
during the menstrual cycle. Although the changes in the cervical
mucus are much more noticeable than the changes in the oral
mucus, both changes are readily determinable. During the immediate
preovulatory phase under estrogen domination ~or a period of
one to three days, the mucus ~s profuse and watery. During_
the postovulatory phase, under progestation, the mucus becomes
less abundant and highly viscous. In healthy women with normal
menstrual cycles, as is well documented in the medical literature,
ovulation usually occurs between the 12th and 14th day prior to
the next menstrual period. Specifically, cervical mucus is most
hydrated (97 to 98% water) at the time of ovulation and is
relatively dehydrated (80 to 90% water) at other times. The
solid residue present after desiccation may range from 2~ during
o~ulation to 20% at other times, a ten fold increase. Determining
ovulation on the basis of the preceeding menstrual period, such
as in the rythm method of counting the days ellapsed between the
termination of the menstrual period and the presumed midcycle
ovulatory phase, is prone to errors because of the great
variability in the length:of the proliferative period, i.e.
between the end of the menses and ovulation. Although it is
possible to predict ovulation on the basis of hormonal changes
in the blood or chemical changes in the mucus, present pro-
cedures for such anal~ses besides being lengthly and costly,
do not provide immediate result. In consequance, these pro-
cedures are utilized only in special cases. At present, there
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are no known reliable on-the-spot techniques that are capable of
providing the information necessary for prediction or confirmation
of ovulation during or immediately following examination of a
patient.
S Summary of the Invention
The primary object of the present invention is to provide
processes and devices for determining the rheological properties
of biological and other liquids. Generally, the device comprises
an inner bearing member having a hori~ontally disposed outer
cylindrical surface and an outer bearing member havi,ng.a _
horizontally disposed inner cylindrical surface, each cylindrical
surface constituting a bearing surface of predetermined grit.
A liquid sample îs introduced between the hori~ontally disposed
outer cylindrical surface of the inner bearing member and the
horizontally disposed inner cylindrical surface of the outer
bearing member, the cylindrical surfaces being eccentrically
oriented relative to one another~ One bearing member is fixed and
the o~her bearing member is biased. Relative mechanical mo~ement
of the bearing members, a rotational movement about eccentric
bearing surface axes that is related to both shear and displacement
of the liquid sample, provides an indication of the rheological
properties of the liquid.
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It is another object of the invention to provide processes
and devices for obtaining affd testing a bodily mucus sample in
order to determine menstrual cycle phase by introducing the mucus
sample between a horizontally disposed outer cylindrical surface
of an inner bearing member and a horizontally disposed inner cylin-
drical surface of an outer bearing member, the cylindrical surfaces
being eccentrically oriented relative to one another. One bearing
member is fixed and the other bearing member is biased, each cylin-
drical surface constituting a bearing surface of predetermined grit.
Mechanical movement or the absence of such movement of the biased
bearing member relative to the fixed bearing denotes the menstrual
cycle phase and provides indicia of ovulation. The inner and outer
bearing members are individually separable from each other and from
a sùpport so that they can be sterilized or replaced. The motion
between the bearing members is a rotational movement about eccentric
bearing surface axes, each of which is horizontally disposed.
Ordinarily, the mucus is supplied to one of the bearing surfaces
while the bearing members are disassembled from each other and the
mucus is extruded between the bearing surfaces when they are assemb-
led with each other. In one form, one of the bearing members isfixed on a~suitable support and the other is provided with a biasing
member, e.g. a weight or a spring, which exerts sufficient force to
cause relative movement when the highly fluid mucus has been sampled
during the ovulatory phase but insufficient force to cause relative
movement when the viscous mucus has been sampled at other times
during the menstrual period. In another form, one of the bearing
members is an extension
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of an elongated probe, which is inserted into the vaginal cavity and
held against the external os. for retrieval of acervicalmucus spec-
imen. In accordance with the present invention, it has been dis-
covered that the foregoing operation requires that the bearing member
have inner and outer bearing surfaces, each characterized by a surface
finish having valleys and peaks of from 8 to 125 microinches in
average valley to peak height. Such a surface finish, in various
embodiments, is provided by precision grinding, machining or etching
random valleys and peaks or machining or etching regularly spaced
prismatic facets or the like. It is believed that this specific sur-
face roughness controls slippage of the mucus with respect to the
bearing surfaces and ensures the occurrence of predetermined shear
within the mucus interior and displacement of the mucus between the
eccentric surfaces.
Other objects of the present invention will in part be
obvious and will in part appear hereinafter.
The invention accordingly comprises the processes and
devices, together with their steps, parts and interrelationships,
which are exemplified in the present disclosure, the scope of which
will be indicated in the appended claims.
_ ief Description of the Drawings_
For a fuller understanding of the nature and objects of
the present invention, reference is made to the following detalled
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description, which is to be taken in connection with the
accompanying drawings, wherein:
Fig. 1 illustrates certain principles o the invention;
Fig. 2 illustrates certain principles of the invention;
Fig. 3 is a perspective view of a de~ice embodying the
~)resent invention, with parts-assembled for the performance
of certain steps of a process of the present invention;
Fig. 4 is a sectional of the device of Fig. 3;
Fig. 5 illustra~es an auxilliary instrument useful in
the performance of certain steps of the present invention;
Fig. 6 illustrates another auxilliary instrument useful
in the performance of certain steps of the present invention;
Fig. 7 is a perspec~ive view of another device embodying
the present invention, with parts disasse~bled ~o~.the performance
of certain steps of the process of the pre~ent invention; and
Fig. 8 is a perspective view-of-the-~evi-ce-of Fig.--~, wi~h--
parts assembled for the performance of othex steps of the present
invention.
Detailed Description of ~he Preferred Em~odiments
The present invention provides processes and devices for
determining the rheological properties of biological and other
liquids involving horizontally disposed bearing ~urfaces that
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are eccentrically oriented with respect to one another. The
basic principles of operation are believed to involve~
the shear of a liquid between two coaxial rotating surfaces
and (2) the displacement of li~uid through the eccentric dis-
position of two bearing surfaces which relates to resistance
flow measurements in capillary viscometry.- The shear and
displacement of the liquid occur at the same time. ~ -
Parameters illustrating certa-in-principles of the in-
vention are shown in Fig. 1, wherein
R = radi~s of inner cylinder
h = radius of outer cylinder
c = clearance
Q = angular velocity or displacement
~ = angle between a radius vector and the 2 axis
e = eccentricity
h = film thickness
The film thickness h depends both upon the cleàrance c and --
upon the eccentricity e. For c~R ~<1
h = c(l + E COS ~)
where E iS the eccentricity ratio e/c
In the present case, the radii, angular displacement (maximum
of 90l and clearances are known as priori, but the ~iscosity
and eccentricity ratio are not. Experimental data indicates that
the eccentricity ratio is determined from the weight per unit area
of the outer cylinder and the vi~cosity of the liquid measured,
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there being no relative motion between the cylinders and the
liquid in immediate contact wi~ the cylinders. The eccentricity
ratio is a constant when designi.ng the instrument and becomes
variable when a liquid is introduced between the cylinders. In
operation, the eccentricity decreases for liquids characteri~ed
by low viscosity and increases for liquids characterized by high
viscosity. Experimental data ~hows that the eccentricity ratio
is larger for saliva than for cervical mucus using the same weight
cylinder. By gelecting outer cylinders of predetermined mass,
measurements within certain viscosity ranges may be performed-under
near-optimal conditions for eccentricity ratio 'E torque to yield
t~e largest numerical valves.
In a coaxial viscometer, the coefflcient of viscosity is
defined as
n~
where n = viscosity
M = torque tmoment)
Q = angular displacement in radians or angular velocity
In a capillary-tube viscometer, the volume displaced per
second is defined as
V= ~P/n
where V = displaced volume per second
aP = pressure difference
In the present case ~P i~ operationally analagous to M and
n= ~P/V
In eccentric viscometry, the equation defining the coefficient
of viscosity for a coaxial vi~c~meter and the e~uation defining
volume displaced per second for a capillary-t~be vi6cometer
combine to yield
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= M'/~
where M' = (f) V as well as coaxial movement.
As illustrated in Fig. 2, if the moment M is constant,
the viscosity~1 of a liquid between the eccentric cylinder is
obtained as a function of angular displacement. No angular dis-
placement, position A as shown by the solid lines in Fig. 2, de-
notes that the moment is insufficient to overcome the viscocity
of the liquid and provides an indication that the viscosity is
high. Maximum angular displacement,- position D as shown by the
dashed lines, denotes that the moment is sufficient to overcome
the viscosity of the liquid and provides an indication that the
viscosity is low. Intermediate positions B and C reflect values
between the two and serve to indicate the approaching time of
minimal viscosity.
Referring now to Figs. 3 and 4, there is shown an eccentric
viscometer 20 in the form of a torque-gauge comprising an inner
bearing member 22, an outer bearing member 24, a biasing member 26,
a support 28, and indicia 30. Support 28, which includes a grip 32,
a chuck 34 and a release mechanism 36, is composed of a suitable
plastic such as methyl methacrylate or polycarbonate. Chuck 34
includes a cylindrical head 37 and a rearwardly extending shaft 39.
Head 37 is provided with a horizontally extending central opening
38 having a holder 40, example an "O" ring.
Inner bearing member 22 is in the form of a short cylin-
drical rod having along its axis a rearward extension 42 and a for-
ward cylindrical outer bearing surface 44. Extension 42, which re-
movably fits into opening 38 and is snugly held therein by holder
40, maintains a horizontal orientation of the axis of
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bearing member 22 when bearing member 22 and support 28 are
assembled. Outer bearing member 24 is in ~he form of a ring
having an axis along which are disposed forward and rearward
parallel flat faces 46, 48 an outer cy~indrical periphery 50
and an inner cylindrical bearing surface 52. outer bearing
surface 44 and inner bearing surface 52 snugly and rotatably
fit each other when ~earing members 22 and.24 are assembled.
The bearing surfaces are orien~ed substantially horiæontal
and are disposed eccentrically relative to one another, where-
by a crescent shape gap 54 is formed b~tween outer bearing
surface 44 and inner ~earing surface 52 when bearing members
22 and 24 are assembled, the gap being shown somewhat exaggerated
for clarity~ That is, the weight of outer bearing member 24 is
such that the upper regions of hori~ontally disposed outer bearing
surface 44 o~ inner bearing member 22 is urged towards the upper
regions of horizontally disposed inner bearing surface 52 of
outer bearing member 24, gap 54 being formed between the lower
regions of the bearing surfaces. The eccentrically disposed
bearing members 22 and 24 define a horizontally disposed eccentric
viscometer, the operation of which i5 dependent upon the wei~ht
of outer bearing member 24 and the non-uniform and the changeable
dimensions of gap 54.
In accordance with the present invention, each of bearing
surfaces 44, 52 requir~s a surface finish ra~ging from 8 to 125
microinches in a~erage valley to peak height, Also, the difference
between the diametral profiles of the bearing surfaces ranges
from 0.01 to 10.0 mils and preferably from 1 to 5 mils. Preferably
the axial thickness of outer beaxing membar 22 ranges from 1/4
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to 2 inches. The weight of outer bearing member 22 is in the
range of 5 grams to 500grams and preferably from 10 grams to
50 grams. In one example, using oral mucus, the weiqht of outer
be.aring member 22 is 10 grams. In another example, using
cervical mucus, the weight of outer.bearing member 22. i5 48-grams.
Preferably each of the bearing members is composed of a dimension-
ally stable, sterilizable material, for example,-a vitreous
material such as glass, a metallic material such as stainless
steel, or a plastic material such as methyl methacrylate.
Biasing member 26 includes an externally threaded rod 56
and an internally threaded weighted ring 58. Rod 56, which is
composed.of plastic or metal for.example, is frictioaally secured
within a bore 60 that extends through periphery 50 of outer
bearing member 24. Ring 58, which is composed o~ plastic or
metal for example, is turned onto rod 56~ The position of ring
58 with respect to the axis of outer bearing memb~r 24 can be
adjusted precisely by turning the ring onto rod 56.
Grip 32 inclues a head 62 and a handle 64. Shaft 39 of
chuck 34 is freely rotatable within a bearing 66 that is mounted
to head 62. Release mechanism 35, which includes a trigger 68
and an extending arm 70, is pivotally mounted to handle 64. The
tip of arm 70, which defines a brake, is received within a notch
72 that is formed in outer bearing member 24. When arm 70 and
notch 72 are engaged, release mechanism 36 is in the locked
position and when arm 70 and notch 72 are disengaged,.release mech
anism 36 is in the unlocked position. Release mechanism 36 is
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is biased in the locked position by means of a spring 74 whi~h
is mounted to trigger 68, the locked position being shown in
Fig. 3. When trigger 68 is pulled inwardly against spring 74,
arm 70 disengages notch 72 and outer bearing member 24 is rotatable
-with~respect to inner bearing member 22, release mechanism being
in the unlocked position.
Indicia 30 include an outwardly directed arrow 76 on the free
end of~shaft 39 and a scale 78 on a rearward face of head 62, scale
78 being marked in gram - cm. When the inner and outer bearing
members are assembled with mucus between their bearing surfaces
and the release mechanism is in the locked position, weighted
ring 58 is in a position to cause rotar~ motion of the outer
bearing member with respect to the inner bearing member when the
release mechanism is actuated to the unlocked position. Initially,
arrow 76 is pointing upwardly towards the zero marking on scale
78 as shown at 79. The arrangement is such that when the mucus
between the bearing ~urfaces is highly water~, weighted ring 58
rotates outer bearing member 24 in a clockwise direction and
arrow 76 remains pointed upwardly. On the other hand, when the
mucus is highly viscous, weighted ring 58 is incapable o rotating
outer bearing member 24, whereby arrow 76 moves clockwise 90
due to the rotational resistance~ The angular displacement of
arrow 76 is a function of the relative viscosity of the mucus.
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In contrast to the opera-tional characteristics of a concentric
viscometer, the operational characteristics of the eccentric vis-
cometer of the present invention are such that: (1) the mucus,
which is displaced when outer bearing member 24 rotates, offers
rotational resistance in addition to conventional shear due to the
eccentrically disposed bearing surfaces; (2) the weight of outer
bearing member 24 resists the torque; and (3) the dimensions of
gap 54 varies during rotation.
One process of the present invention involves the use of
sterile inner and outer bearing members 22, 24 as follows. First,
inner bearing member 22 is assembled with chuck 34 by inserting
extension 42 into opening 38. Next, chuck 34 is rotated until
arrow 76 points to the zero marking on scale 78. Next, a sample
80 of cervical mucus is obtained by inserting a disposable probe
82 having an elastomeric scoop 84 at its extremity through the
vaginal cavity into contact with the cervix in order to retain the
sample of cervical mucus. Next, this cervical mucus is transferred
to one of bearing surfaces 44, 52 and the inner and outer bearing
members are assembled by fitting outer bearing member 24 onto inner
bearing member 22, the arrangement being such that the cervical
mucus is extruded between the bearing surfaces. Outer bearing
member 24 is positioned so that arm 70 engages notch 72, the longi-
tudinal axis of rod 56 being perpendicular with respect to the long-
itudinal axis of handle 64. Then, trigger 68 is pressed inwardly
and release mechanism 68 is actuated to the unlocked position.
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During the time of ovulation, the mucus is watery and the rot-
ational resistance is minimum. In consequence, when release
mechanism 36 is actuated to the unlocked position, rod 56 rotates
clockwise and arrow 76 remains stationary. At other times, the
mucus is highly viscous and the rotational resistance is maximum.
In consequence, when the release mechanism is in the unlocked posi-
tion, rod 56 remains stationary and arrow 56 rotates clockwise.
Finally, the position of arrow 76, a comparative indication of
viscosity, denotes the presence or absence of ovulation. In this
process, the weight of outer bearing member 24 i~s 48 grams. The
quantity of cervical mucus displaced as ring 58 travels in a 90
degree arcuate path is in the range of 3 mg to 5 mg, the mucus
being positively displaced without homogenation of the mucus or
the destruction of its viscoelastic properties during the measure-
ment.
In an alternative process, oral mucus, i.e. saliva, is
removed from the mouth by an eye dropper 86 having a tube 88
with a restricted end 90 and an elastomeric bulb 92. Here, saliva
is applied to one of bearing surfaces 44, 52 simply by manually
squeezing bulb 92 and extruding saliva through opening 90. This
process otherwise is identical to that described above in connection
with cervical mucus. In this process, the weight of outer bearing
member 24 is 10 grams.
The embodiment of Figs. 7 and 8 includes an elongated
cylindrical probe 100, at the forward extremity of which is a cy-
lindrical extension 102 of reduced diameter that is isolated
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from the remainder of the probe by a ~houlder 104. The forward
extremity of extension 102 is rounded as at 106. Associated with
probe 100 is an annulus 108 having an inner bore 110 and forward
and rearward fla~ parallel faces 112, 114. The outer bearing
surface of extension 102 and the inner bearing surface of bore
110 snugly fit each other when ring 108 and pro~e 100 are
assembled, a crescent shaped gap 115 being formed between the
bearing suraces. Extending from the periphery of ring 108 is
a threaded shaft 116 having turned thereon an adjustable nut
118, the shaft and the nut serving as an adjustable torque
weight. Probe 100 and ring 108 are composed of the same
materials as are their counterparts in Figs. 3 and 4. Also the
dimensions and grit characteris~ics of extension bearing surface
102 and of bore bearing surface 110 are the same as are their
counterparts in Figs. 3 and 4~
In operation of the device of Figs. 7 and 8, first probe
100 is inserted into the vaginal cavity so that extension 102
contacts the cervix, by which a ~uantity of cervical mucus is
retained on the bearing surface of extension 102. Next probe
100 is withdrawn from the vaginal cavity and is assembled with
ring 108 so that extension 102 i5 inserted into bore 110 and
rearward movement of ring 108 is limited by ~houlder 104. At
this point cervical mucus is extruded between the bearing surfaces
of bore 110 and extension 102. Then a nser, while holding probe
100 horizontally in one hand, moves shaft 116 into horizontal
orientation with the other hand. Finally when shaft 116 is
released, eccentric rotation of ring 108 relative to probe 100
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under the torque of weight 118 will or will not cccur.
Menstrual cycle phase thereby will be indicated in accordance
with the present invention.
Since certain changes may be made in the present disclosure
S without-departing from the scope of the-prese~t invention, it
is intended that all matter described in the foregoi~g specifica-
tion and depicted in the accompanying drawings be interpreted
in an illustrative and not in a limiting sense.
