Note: Descriptions are shown in the official language in which they were submitted.
1~253~'77
BACKGROUND OF THE INVENTION
The present invention relates generally to improv-
ing the dispersibility of agglomerated hygroscopic powders
such as pregelatinized starch, whole milk, skim milk, whole
milk replacer, whey powders, powdered yeast and fish protein
extracts, animal feeds, baby foods, and maltodextrines. More
specifically, in its presently preferred form, the invention
relates to methods for enhancing the dispersibility of ag-
glomerated pregelatinized starch and to resulting composi-
tions of easily dispersible agglomerated pregelatinized
starch.
Mammals, including ruminants such as cattle and
sheep and monogastric animals such as pigs, horses and human
beings, often suffer from diarrhea or "scours". It has been
reported that diarrhea is a serious health problem for adult
cattle (U.S. Patent 3,911,114) and causes high mortality
rates for neonatal calves (U.S. Patent 4,009,268). Mono-
gastric animals, including pigs, horses and humans, are also
reported to suffer significantly from diarrhea (U.S. Patent
4,120,952), i.e., one-fifth of newborn pigs which contract
diarrhea die without treatment (U.S. Patent 4,010,262).
The above-mentioned patents disclose methods for
treating diarrhea in the animal by administering oral
dosages of an aqueous mixture of an antidiarrheal agent,
pregelatinized starch (PGS). Typically the methods involve
mixing a dry pregelatinized starch commercial product with
water and forcing the resultant PGS solution or paste down a
tube inserted in the animal's throat. (See, e.g., U.S.
Patents 3,911,114 and 4,010,262.) Other disclosed methods
~J~
1~53(:~77
include mixing the pregelatinized starch with other liquids,
such as milk, and feeding the mixture to the animal. (See,
U.S. Patent 4,120,952).
Although PGS appears to be an effective anti-
diarrheal agent, mixing pregelatinized starch with liquids
is difficult due to the intrinsic properties of the starch.
As produced commercially, pregelatinized starch is an ex-
tremely hygroscopic powder. Characteristic of hygroscopic
powders, PGS disperses with difficulty in aqueous media. If
added directly to such media too quickly and without suf~i-
cient agitation, the dry starch powder becomes encapsulated
by stiff paste into balls of material which are very diffi-
cult to disperse. This incomplete dispersion makes the
mixture more difficult to administer to the patient to the
point that force-feeding may be required. Incomplete dis-
persion also means that a greater amount of pregelatinized
starch may be required to achieve the desired antidiarrheic
effect than if complete dispersal had been obtained.
The wettability of pregelatinized starch can be
enhanced by agglomerating the particles of pregelatinized
starch through controlled addition of water and redrying.
The result is a coarse powder, agglomerated pregelatinized
starch (APGS), that wets more readily in aqueous media and
disperses more easily than pregelatinized starch. However,
substantial care is still required when mixing agglomerated
pregelatinized starch in water to avoid formation of lumps
of stiff paste which resist dispersion.
In application of pregelatinized starch composi-
tions such as PGS or APGS as an antidiarrheal, unskilled
--3--
persons are expected to mix the compositions into water or
aqueous suspensions and administer the solution orally to
the patient. In intensive livestock production enterprises,
however, instructions to take special precautions to mix
medications slowly and carefully are often unheeded. To be
accepted for routine use, a pregelatinized starch anti-
diarrheal product must be readily dispersible in aqueous
media without the need for exceptional precautions for mix-
ing, and with great margin for error. Thus formulations of
pregelatinized starch compositions with mixing qualities
superior to both PGS and APGS compositions presently avail-
able are required.
It is generally known in the art that the dis-
persibility of a composition can be improved through incor-
poration of a "dispersant" component which readily absorbs
i water. Many compounds are known to act as dispersants for
certain compositions including raw starch used in tableting
as an excipient and as a dispersant for PGS, and FDA
approved anticaking agents for animal feeds such as poly-
sorbate-60 and polysorbate-80. Sodium aluminum silicate may
similarly be employed as an anticaking agent. U.S. Patent
3,332,848 (Col. 1, line 68 to Col. 2, line 4) discloses
incorporation of microcrystalline cellulose into multiple
vitamin tablets to enhance the dispersibility of the tablets
in aqueous vehicles. U.S. Patent 3,696,637 discloses en-
hancing the dispersibility of estrogen in aqueous solutions
by admixing microcrystalline cellulose with the hormone
prior to mixing with water.
125307~
--4--
Although dispersants are generally known as a
class, the choice of a dispersant is dependent primarily on
the composition sought to be dispersed and the context
within which the composition is intended to be used. In the
present case, the dispersant must interact with a hygro-
scopic powder, APGS~ intended to be ingested by livestock on
a large-scale basis, and by human beings. It is therefore
essential that the dispersant be non-toxic, inert and inex-
pensive. It is also preferred that the dispersant be a
lo constituent of the normal diet of the patient. Further
restrictions exist with respect to the nature and amount of
dispersants that may be fed to livestock raised for human
consumption, e.g., the U.S. Food ~ Drug Administration would
be expected to require extensive retesting of PGS if the
amount of dispersant in the antidiarrheal compositions were
to exceed 10~. These and other regulatory restrictions
would likely exist with respect to agglomerated hygroscopic
powders such as milk, baby food, protein extracts and the
like which are intended for direct human consumption.
As noted above, microcrystalline cellulose has
been reported to function as a dispersant for estrogen in
aqueous mixtures administered to cattle, (U.S. Patent
3,639,637), and as a dispersant in vitamin tablets (U.S.
Patent 3,332,848). Microcrystalline cellulose is purified
alpha cellulose particles prepared from processing alpha
cellulose from fibrous plant materials. It is an inert,
organic material and is a commercial product sold under
various tradenames including Avicel (American Viscose Divi-
sion, FMC Corp.), as an excipient and extender in pharma-
ceutical tableting. (Avicel0 Sales Brochure).
1~53077
Although microcrystalline cellulose initially
appears attractive as a possible dispersant for APGS, actual
testing consistent with this suggestion has proven unsuc-
cessful. As indicated in more detail below, applicant
prepared mixtures of various proportions of microcrystalline
cellulose and the antidiarrheal APGS starch. It was found
that a minimum of 35% to 40~ microcrystalline cellulose was
required to significantly improve the dispersibility of
APGS. The size of the microcrystalline cellulose particles
was also found to influence dispersibility, the smaller
sized particles (20 microns) belng more effective than the
larger 50 micron and ~0 micron particles. At concentrations
of about 35~ microcrystalline cellulose, the cost of the
mixture was three times that of APGS alone.
There continues to exist, therefore, a need in the
art for a method of enhancing the dispersibility of agglom-
erated hygroscopic powders such as APGS and for easily dis-
persible APGS antidiarrheal compositions.
BRIEF SUMMARY OF THE INVENTION
The present invention provides novel methods for
enhancing the dispersibility of agglomerated hygroscopic
powders such as agglomerated pregelatinized starch (APGS)
which comprises admixing the powder with a dispersionally
effective amount of fibrous cellulose having an average
fibre length of greater than l00 microns.
Presently preferred dispersionally effective
amounts of fibrous cellulose for use in these methods are
those providing, on a dry weight basis, about l0 weight
percent or less (and more preferably 6 to 7 weight percent)
l~S3(:~'77
--6--
of the total weight of the admixture. Preferred fibrous
cellulose materials for use in the invention have an average
fibre length of between about 120 to 290 microns, and most
preferably, an average fibre length of about 290 microns.
Exemplary easily dispersible hygroscopic powder
compositions according to the invention include admixtures
of APGS and dispersionally effective amounts of fibrous
cellulose having an average fibre length of greater than 100
microns. Preferred compositions include admixtures of, on a
dry weight basis, about 90 to 94 percent APGS and about 6 to
lO percent fibrous cellulose having an average fibre length
of between 120 and 290 microns. Presently most highly pre-
ferred compositions are those which include 93 to 94 percent
APGS and 6 to 7 percent fibrous cellulose with a 290 micron
average fibre length.
Compositions of the invention possess enhanced
dispersibility in aqueous media. Such enhanced dispersion
is readily achieved without the need for careful mixing
steps or elaborate mixing equipment. Compositions according
to the invention flow in live-bottom automated packaging
equipment, further facilitating their use on a large-scale
basis.
Commercially available fibrous cellulose may be
employed in the present invention without the need for
treatment of fibres to render them hydrophobic, in distinc-
tion to use of lypophilized fibrous cellulose food thicken-
ing agents as disclosed in U.S. Patent 4,198,400.
Other aspects and advantages of the invention will
become apparent upon consideration of the following detailed
lZ53077
.
description wherein FIG.l graphically illustrates the en-
hanced dispersibility of APGS consistent with methods and
compositions according to the invention.
DETAILED DESCRIPTION
EXAMPLE 1
Dispersion of Agglomerated Pregelatinized
Starch By Admixture of Fibrous Cellulose
Samples of dry fibrous cellulose were obtained
from Grefco, Inc., Torrence, California. The samples,
Solka- FIoc~ BW-100 (fibre length 35-45 microns) and Solka-
Floc~ KS-1016 (fibre length 290 microns), were tested for
their effectiveness in aiding dispersion of dry powdered
agglomerated pregelatinized starch (APGS) Diamylex0 (Shulcon
Industries, Phoenix, Arizona), as follows.
lS Each fibrous cellulose sample was mixed with 30
grams of the agglomerated pregelatinized starch in concen-
trations of 10, 15 and 20% fibrous cellulose, and the dry
fibrous cellulose/APGS mixtures were tested for dispersion
in water at room temperature according to the following
protocol.
Each mixture, containing 309 of agglomerated pre-
gelatinized starch and the appropriate quantity of fibrous
cellulose was added to the quiescent surface of 1 liter of
water in a cylindrical container 6 inches in diameter and 6
3/4 inches tall. The dry mixture was added suddenly and
allowed to stand without agitation for 30 seconds. The con-
tents of the can were then swirled 100 times in 30 seconds
and then poured through a piece of 1/8 inch mesh hardware
cloth. The sides of the container were washed with a small
amount of water and the washings were poured over any
~Z53(~ 7
--8--
retained material on the hardware cloth. Material retained
on the hardware cloth was transferred to a tared container
and weighed. The mixtures tested were ordered randomly for
the testing sequence using a random numbers table generated
by a Hewlett-Packard Model 97 Desk Calculator.
The results of the experiment are set forth in
Table I, below.
TABLE I
Wet Weight of Solids Retained on
Hardware Cloth ( in grams )
Fibrous Cellulose Fiber Length (Ave.)
% of Fibrous
Cellulose in APGS 35-45~ 290~
0 53.1 58.7
20.8 0
3.7 0
0
The results set forth in Table I indicate that
fibrous cellulose is an effective dispersant and that, of
the types tested, the materials having the longest (e.g.,
290 micron) average fibre length is the most effective on a
weight basis. The effective concentration of 290 micron
fibres is 10 percent or less, on a dry weight basis, of the
total admixture.
The following Example illustrates an experiment
examining the dispersion effect of 290 micron fibrous cellu-
lose on agglomerated pregelatinized starch at lower concen-
trations of the fibrous cellulose and in warm water.
EXAMPLE 2
Dispersion Effect of 290~
Fibrous Cellulose on APGS
lZS3V'77
g
Solka-Floc~ fibrous cellulose KS-1016 (290~) was
mixed with agglomerated pregelatinized starch (APGS) in
amounts of 1, 2 and 3 grams of fibrous cellulose per 30
grams APGS and tested against the dispersibility of APGS
alone in random order according to the protocol of Example
1, except the water temperature was raised to 115-117F.
The results of this experiment are set forth in
Table II below.
TABLE II
Wet Weight of Solids Retained
on Hardware Screen (in grams)
Grams of 290 Micron Fibrous Cellulose/309 APGS
Replicate # _ 1 2 3_
1 43.7 16.0 0 0
2 45.8 12.1 0 0
3 48.5 14.5 o 0
(Means 46.0 14.2 0 0)
S.D. +2.41 +1.97 0 0
The results set forth in Table II show that 6.3%
(i.e., 2g/32g mixture x 100%) of Solka-Floc~ KS-1016 fibrous
cellulose having an average fibre length of 290 microns in
an admixture with APGS effectively acts as an aid in
dispersing the APGS in water. There appears to be little
influence of temperature on the test results using this
system. When mixed with an adequate quantity of 290 micron
fibre length fibrous cellulose to permit complete dispersion
of the APGS, the mixture floats on the surface of the water
until a concerted effort is made to mix it. The dispersion
effectiveness of the 290 micron fibrous cellulose may be
partially attributable to its extreme buoyancy, inhibiting
premature wetting of the starch.
1~53077
--10--
.
The following example illustrates testing of the
dispersion effect of fibrous cellulose having average fibre
lengths of 120 microns on agglomerated pregelatinized
starch.
EXAMPLE 3
Dispersion Effect of 120~
Fibrous Cellulose on APGS
Solka-Floc~ KS-1040, with an average fiber length
of 120 microns was tested as a dispersant for agglomerated
pregelatinized starch (APGS), employing 1, 2, or 3g of the
120 micron fibrous cellulose per 30g of APGS. The test
system used is described in Example 1. The results obtained
are set forth in Table III below.
TABLE III
Wet Weightof Solids Retained
on Hardward Cloth (in grams)
Grams of 120 Micron Eibr~bLLla~L~L~ 9
Replicate # 1 2 3
1 36.8 10.6 3.8
2 38.4 19.0 6.8
3 40.3 8.2 2.8
(Means 38.5 12.6 4.47)
S.D. +1.75 +5.67 +2.08
These results indicate that fibrous cellulose
having a fibre length of about 120 microns is an effective
dispersant of APGS at amounts of about 10 weight percent.
The following Example illustrates the dispersion
effect of fibrous cellulose on unagglomerated pregelatinized
starch (PGS).
1~53~ '7
EXAMPLE 4
Dispersion of Pregelatinized
Starch 8y Fibrous Cellulose
Tests were performed to evaluate the dispersi-
bility of unagglomerated pregelatinized starch (PGS) with
fibrous celluloses of two different fiber lengths, 290 mic-
rons (Solka- Floc~ KS-1016) and 35-45 microns (Solka-Floc~
BW-100). The test methods of Example 1 were followed. The
results are set forth below.
TABLE IV
Wet Weight of Solids Retained
on Hardward Cloth (in grams)
g Fibrous Fibre Length of Fibrous Cellulose
Cellulose/30g PGS Replicate 35-45~ 290-
2.00 1 --- 43.2
3.33 1 47.6 29.4
- 2 53.5 23.9
3 48.7 33.4
(Means 49.93 28.9)
(S.D. +3.1 +4.8)
5.3 1 --- 19.2
2 --- 14.4
3 --- 17.1
Mean --- 16.9
S.D. --- 2.4
6.6 1 37.1 ---
2 34.0 ___
3 33.7 ---
(Mean 34.93 ---
S.D. 1.9 ---
1 21 ~ 14.5
12.9 1 11.5 ---
1~5~t7t7
-12-
As indicated by the above results, 290 micron and
35-45 micron fibrous cellulose present in amounts of 10
weight percent were ineffective in dispersing PGS. Much
higher amounts of even the 290 micron long fibrous cellulose
were required to disperse the 309 sample of PGS.
The following Example illustrates the effect of
microcrystalline cellulose of varying particle size on the
dispersibility of agglomerated pregelatinized starch.
EXAMPLE 5
Dispers~on of Agglomerated Pregelatinized
Starch by Microcrystalline Cellulose
After preliminary tests to establish the range of
concentration of microcrystalline cellulose needed to effect
some degree of dispersion of agglomerated pregelatinized
starch (APGS), three grades of microcrystalline cellulose
were tested for effectiveness in enhancing dispersion of
APGS in water. The test method used is descrlbed in Example
1. Avicel~ microcrystalline cellulose products PH-105 (par-
ticle size, 20 microns), PH-101 (particle size, 50 microns)
and PH-102 (particle size, 90 microns) were employed. The
results are set forth in Table V below.
.0
-13-
TABLE V
Wet Weightof Solids Retained
on Hardware Cloth (in grams)
g Micro- Microcrystalline Cellulose Particle Size
crystalline
Cellulose/
5 30g APGS Replicate 20~ 50~ 90
1 0 5.2 8
2 ~ 7.6 2.7
3 3 3.8 6.1
(Means 1.0 5.5 5.6)
S.D. 1.7 1.9 2.7
7.5 1 28.7 44.1 48.8
2 38.7 43.6 45.6
3 26.3 41.6 47.4
(Means 31.2 43.1 47.i)
S.D. +6.6 +1.3 +1.6
The results indicate that even at very high
amounts (i.e., 20%) microcrystalline cellulose does not
significantly disperse APGS. The results also show that the
smaller the size of the microcrystalline cellulose particle,
the greater its ability to disperse APGS.
The following Example illustrates the effectivenss
of preferred methods and compositions according to the in-
vention in treating diarrheic mammals.
EXAMPLE 6
Treatment of Diarrheic Mammals
With Fibrous Cellulose/APGS Admixtures
The therapeutic effectiveness of the admixture of
6.3% fibrous cellulose (Solka-Floc~ KS-1016, 290~) and APGS
(Diamylex~, Shulcon Industries, Phoenix, Arizona) was
evaluated in a clinical field setting. Two hundred (200)
1~53Q'77
diarrheic calves were treated with the admixture according
to the package instructions specifying that one packet (32g)
of the admixture be dissolved in one quart or greater volume
liquid feed and administered to each calf twice daily at
normal feeding times for two days promptly upon the first
occurrence of diarrheic symptoms. The effectiveness of this
treatment was evaluated against treatment of 50 diarrheic
calves using 309 of PGS alone in liquid feed performed as
part of the regulatory approval of PGS as an antidiarrheal.
The results of both treatments are set forth in Table VI,
below.
TABLE VI
Therapeutic Effectiveness of a
Dispersible Fibrous Cellulose/APGS Mixture
6.3% Fibrous
Cellulose (290~)
PGS in APGS
Total # of Calves Treated 50 200
Responding to Treatment* 72 80
*Returned to normal without further or auxiliary
treatment.
As indicated in Table VI, 80% of the diarrheic
calves treated with the 290m fibrous cellulose/APGS admix-
ture responded to the treatment and returned to normal with-
out the need for additional treatment, a response which is
similar to the 72% response rate obtained with PGS alone.
EXAMPLE 7
Dispersion Effect of Fibrous Cellulose
on Antidiarrheal/Nutrient Compositions and
Agglomerated Antidiarrheal/Nutrient Compositions
The dispersion effect of Solka-Floc~ KS-1016
(290~) fibrous cellulose upon antidiarrheal compositions
including nutritional salts and sugar was evaluated
1253(~77
according to the method of Example 1. The first anti-
diarrheal compositions examined included the following
ingredient~.
NaCl - 9.4%
KCl - 3.1
NaHCO~ - 6.7
Dextrose - 53.4
PGS - 21.2~
KS-1016 - 6.2%
100.0%
One batch (70.429) was prepared by mixing all the
above ingredients except the fibrous cellulose and agglom-
erating the mixture. KS-1016 fibrous cellulose (6.2~) was
then admixed to the composition.
A second antidiarrheal composition was prepared
according to the above formula except that 21.2~ APGS was
substituted for the PGS and no agglomeration of this APGS/
nutritional salts and sugar admixture was conducted. An
equal amount (6.2~) of KS-1016 was then admixed with this
antidiarrheal composition. Both compositions were tested
for dispersibility in water according to the method of
Example 1. The results are set forth in Table VII below.
TABLE VII
Sample I Sample II
Wet Wet
Weight Weight
Dry Retained Dry Retained
Antidiarrheal Weight on Screen Weight on Screen
Composition (g) (9) (g) (g)
APGS, Nutritional 37.5 trace 37.5 0.5
Mixture and 290~
Fibrous Cellulose
Agglomerated 37.5 0 37.5 0
PGS/Nutritional
Mixture and290~
Fibrous Cellulose
Agglomerated 35.2 8.5 35.2 12.3
PGS/Nutritional
Mixture Without
290~ Fibrous
Cellulose
-16- lZS3~ 7
As indicated by the above results, the presence of
6.2% of 290u fibrous cellulose significantly increased the
dispersibility of the agglomerated PGS/nutritional salts and
sugar mixture. Additionally, it was observed that fibrous
cellulose also significantly improved the dispersion of APGS
and non-agglomerated nutritional ingredients including the
hygroscopic dextrose component.
FIG.l graphically illustrates the enhanced disper-
sibility of agglomerated pregelatinized starch according to
the methods and compositions of the pr2sent invention. The
data from Examples 1 to 6 pertaining to fibrous cellulose
admixtures with APGS are indicated in Figurel as follows.
The dispersibility of APGS as influenced by varying amounts
of: (1) 290 micron fibrous cellulose (FC) is shown by the
solid line connecting open circles ( _ o ); (2) 120
.
micron fibrous cellulose is shown by the solid line connect-
ing open squares ( _ o ); and (3) the 35-45 micron
fibrous cellulose is shown by the solid line connecting open
triangles ( A_). The effect of 290 micron and 35-45
micron fibrous cellulose on unagglomerated PGS dispersion is
indicated by the broken lines connecting the open circles
(----O----) and triangles (--~ ), respectively. The
data set forth in Example 5 relating to the dispersion
effect of microcrystalline cellulose (MCC) of varying par-
ticle sizes and amounts on APGS is indicated in FIG.l by the
solid lines connecting the filled circles ( , 90
micron), filled squares ( , 50 micron), and filled
triangles ( _ 20 microns).
17 l'~S30 77
As indicated in FIG.l, 35-40% microcrystalline
cellulose is required in a microcrystalline cellulose/APGS
admixture tc effect significant dispersion of the anti-
diarrheal. At this concentration the cost of the micro-
crystalline cellulose would triple the cost of the anti-
diarrheal composition. The results also indicate that the
smaller particles of microcrystalline cellulose (20 microns)
were more effective in dispersing APGS than the larger par-
ticles (50 and 90 microns).
Unexpectedly, applicants have discovered that
fibrous cellulose having certain fibre lengths greatly en-
hance the dispersibility of APGS. As shown in FIG.l, the
amounts of fibrous cellulose required to achieve complete
dispersion of APGS is much less than that of microcrystal-
line cellulose. ~ith materials of similar particle size (35-
45 micron fibrous cellulose v.50 micron microcrystalline
cellulose), about one-fourth the amount of the fibrous
cellulose was required to obtain complete dispersion of APGS
than with the microcrystalline cellulose. In addition, it
was discovered that the dispersibility of APGS was strongly
influenced by increasing fiber length of the cellulosic
material added. In contrast to the results obtained with
microcrystalline cellulose, where smaller particles produced
better dispersibility, increase in fiber length dramatically
improved dispersibility of mixtures of fibrous cellulose
with APGS. The longest fibrous cellulose materials tested
(290 microns) were about 10 times more effective than the
most effective (20 micron particle size) microcrystalline
cellulose in enhancing dispersion.
12~3~it77
-18-
Fibrous cellulose having average fiber lengths of
approximately lO0 microns or greater were effective in
eliciting total dispersion of APGS mixtures with concen-
trations of fibrous cellulose of about 10% or less. At
these low concentrations, the inert organic dispersant
fibrous cellulose has no effect on the antidiarrheal
properties of pregelatinized starch, and the additional cost
of the fibrous cellulose material is well within tolerable
limits.
Fibrous cellulose having fibers of 100 microns or
larger are also more effective than shorter fiber length
material in enhancing dispersibility of PGS in water,
although, as expected, the concentration of fibrous cellu-
lose required was greater than with APGS. The magnitude of
the effect of fiber length was also substantially greater
when APGS was employed in the mixture. The quantity of
fibrous cellulose required for complete dispersion of PGS
was reduced by half when the fiber length was increased from
35-45 microns to 290 microns. The same change in fiber
length resulted in a 75% reduction in fibrous cellulose
concentration with APGS. As indicated in Example 6, actual
clinical field tests utilizing fibrous cellulose/APGS admix-
tures according to the invention proved effective in treat-
ment of diarrheic calves, eighty percent of the diarrheic
calves so treated returning to normal after two days of
treatment.
While the method of Example 2 utilizing the compo-
sition disclosed therein of about 93-94 weight percent APGS
and 6-7 weight percent fibrous cellulose having an average
-19- ~53t~'~'7
fibre length of about 290 microns is clearly the presently
most preferred and thoroughly tested procedure o~ the inven-
tion, it is expected that equally effective results may be
obtained through use of other APGS compositions using lesser
amounts of fibrous cellulose having fibre lengths of greater
than 100 microns consistent with applicant's teachings.
It is also expected that the dispersibility of
other selected agglomerated hygroscopic powders alone or in
conjunction with nutritional ingredients such as those set
forth in Example 7 may be enhanced by admixing them with
dispersionally effective amounts of fibrous ceilulose having
fibre lengths of greater than 100 microns.
Consistent with the foregoing disclosure, numerous
modifications and variations in the practice of the inven-
tlon are expected to occur to those skilled in the art.
Consequently, only those limitations as appear in the ap-
pended claims should be placed on the invention above des-
cribed.
