1. A method of making particles, the method comprising:
obtaining a substantially pure material comprising at least one constituent having a spin-lattice relaxation time T1 greater than about 5 minutes;
reducing the substantially pure material into particles in the presence of one or more solvents; and
separating the particles by size to yield one or more collections of particles exhibiting a spin-lattice relaxation time T1 greater than about 5 minutes.
2. The method as claimed in claim 1, wherein the spin-lattice relaxation time T1 of a yielded collection of particles is greater than about 15 minutes.
3. The method as claimed in claim 1, wherein the substantially pure material is a material selected from the group consisting of: silicon, silica, silicon carbide, silicon nitride, and carbon.
4. The method as claimed in claim 1, wherein the at least one constituent comprises an isotope selected from the group consisting of: 13C, 29Si, and a combination thereof.
5. The method as claimed in claim 1, wherein the stoichiometric purity of the substantially pure material is greater than about 90%.
6. The method as claimed in claim 1, wherein the concentration of the at least one constituent is between about 0.1% and about 100%.
7. The method as claimed in claim 1, wherein the step of reducing comprises reducing bulk material in a machine selected from the following group: a ball mill, a jet mill, a grinding machine, a cutting machine, and any combination thereof.
8. The method as claimed in claim 1, wherein the step of reducing comprises reducing bulk material in a ball mill operated at a speed between about 50 revolutions per minute and about 400 revolutions per minute.
9. The method as claimed in claim 8, wherein the ball mill is operated for a period of time between about 12 hours and about 48 hours.
10. The method as claimed in claim 8, wherein one or more zirconia milling balls having diameters between about 2 mm and about 15 mm are used in the ball mill.
11. The method as claimed in claim 1, wherein the solvent is selected from the group consisting of: water, de-ionized water, distilled water, purified water, ethanol, isopropanol, methanol, and any combination thereof.
12. The method as claimed in claim 1, wherein a yielded collection of particles has an average particle size between about 1 nm and about 200 nm.
13. The method as claimed in claim 1, wherein a yielded collection of particles has an average particle size between about 200 nm and about 1 \u03bcm.
14. The method as claimed in claim 1, wherein a yielded collection of particles has an average particle size between about 1 \u03bcm and about 200 \u03bcm.
15. The method as claimed in claim 1, wherein more than about 90% of the particles within a yielded collection of particles have a size between about 200 nm and about 500 nm.
16. The method as claimed in claim 1 further comprising:
removing contaminants from the surface of the particles.
17. The method as claimed in claim 1 further comprising:
sterilizing the particles.
18. The method as claimed in claim 1, the step of separating the particles by size comprising:
gathering the particles in a solution;
centrifuging the solution to produce a first pellet and a first supernatant; and
subjecting the first supernatant andor the first pellet to one or more subsequent steps of centrifugation.
19. The method as claimed in claim 18, wherein the maximum particle size ds in any of the produced supernatants is selected by choosing centrifugation parameters in accordance with the relation
d
s
<
ln
\ue8a0
(
R
b
R
t
)
\ue89e
9
\ue89e
\ue89e
\u03bc
2
\ue89e
(
\u03c1
p
–
\u03c1
f
)
\ue89e
\u03c9
2
\ue89e
t
\ue89e
\ue89e
wherein
Rt is substantially the location with respect to the centrifuge’s axis of rotation of the top of the fluid containing the particles in a centrifugation vial;
Rb is substantially the location with respect to the centrifuge’s axis of rotation of the bottom of the vial;
\u03c9 is substantially the angular velocity at which the centrifuge is operated;
t is substantially the duration of centrifugation;
\u03bc is substantially the viscosity of the fluid containing the particles;
\u03c1f is substantially the density of the fluid containing the particles; and
\u03c1p is substantially the density of the particles.
20. The method as claimed in claim 1, the step of separating the particles by size comprising:
gathering the particles in a solution;
sonicating the solution;
centrifuging the solution;
decanting a supernatant from the centrifuged solution; and
removing excess liquid from the supernatant.
21. The method as claimed in claim 20 further comprising:
letting the sonicated solution stand without substantial motion for a period between about 12 hours and about 48 hours.
22. The method as claimed in claim 20, wherein the step of centrifuging is carried out at a value between about 2,500 relative centrifugal force and about 4,500 relative centrifugal force, and for a time between about 1 minute and about 90 minutes.
23. The method as claimed in claim 1, wherein the substantially pure material is in a material form selected from the group consisting of: amorphous, crystalline, porous, polycrystalline, nanocrystalline, or co-crystalline.
24. The method as claimed in claim 1, the step of separating the particles by size comprising:
gathering the particles in a solution;
sonicating the solution;
letting the sonicated solution stand without substantial motion for a period of time;
centrifuging the solution;
decanting a first supernatant from the centrifuged solution;
centrifuging the first supernatant to produce a second supernatant and pellet;
decanting the second supernatant; and
removing excess liquid from the pellet to yield a collection of particles.
25. The method as claimed in claim 1, the step of separating the particles by size comprising:
gathering the particles in a solution;
sonicating the solution;
letting the sonicated solution stand without substantial motion for a period of time;
centrifuging the solution;
decanting a first supernatant from the centrifuged solution;
filtering the first supernatant to produce a filtrate;
centrifuging the filtrate to produce a pellet of particles; and
removing excess liquid from the pellet to yield a collection of particles.
26. The method as claimed in claim 25, wherein the filtering is carried out sequentially with filters of gradually reducing pore size.
27. The method as claimed in claim 25, wherein the removing of excess liquid is done by lyophilization.
28. The method as claimed in claim 25, wherein the step of removing of contaminants from the surface of the particles comprises a process step selected from the group consisting of: immersion in hydrofluoric acid, immersion in a mixture of sulfuric acid and hydrogen peroxide, and immersion in a heated mixture of water, hydrogen peroxide and ammonium hydroxide.
29. The method of claim 1, further comprising:
coating the particles with a passivating moiety, the passivating moiety providing a protective layer enabling the particle to withstand a living system’s natural defense against foreign bodies.
30. The method of claim 1, further comprising:
chemically functionalizing the surface of the particles with a ligand so that the particle binds specifically to a desired target cell type, molecule, or molecular expression.
31. The method of claim 1, wherein the particles within the yielded collection of particles are porous, and further comprising:
subjecting the porous particles to a drug-loading process, wherein the particles are exposed to a drug to be loaded into the vacancies of the particles.
32. A collection of particles produced by the method of claim 1, the collection of particles having an average particle size between about 1 nm and about 200 \u03bcm and a characteristic spin-lattice relaxation time T1 greater than about 15 minutes.
33. A collection of particles having an average particle size between about 1 nm and about 200 \u03bcm, the collection of particles having a characteristic spin-lattice relaxation time T1 greater than about 15 minutes.
34. The collection of particles as claimed in claim 33, wherein the collection was produced by a method comprising multiple steps of centrifugation.
35. The collection of particles as claimed in claim 33, wherein more than about 90% of the particles have a size within a range between about \xb160% of the average particle size.
36. The collection of particles as claimed in claim 33, wherein more than about 90% of the particles have a size within a range between about \xb140% of the average particle size.
37. A method of delivering particles to a specimen or subject, the method comprising:
using the collection of particles of claim 33; and
delivering a selected quantity of the particles internally to the specimen or subject.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
We claim:
1. A depilatory for removal of body hair comprising:
a water soluble or water dispersable hot melt adhesive blend coated on a first substrate and overlaid with a second substrate in a continuous fashion and cut to size dependent upon the area of the body to which it is applied.
2. The depilatory in accordance with claim 1 wherein said first substrate and said second substrate are formed from a polymer such as polypropylene or other suitable plastic film.
3. The depilatory in accordance with claim 1 wherein said first substrate and said second substrate are formed from a cellulosic material.
4. The depilatory in accordance with claim 1 wherein said water soluble adhesive is comprised of hydrogenated rosin, dipropylene glycol dibenzoate, 1,4-cyclohexane di-methanol dibenzoate, ethoxylated alcohol, a water soluble or dispersable sulfo-polyester, poly(vinyl) pyrrolidone acetate and anti-oxidants.
5. The depilatory in accordance with claim 4 wherein said hydrogenated rosin is present in a range of from 5 to 40 percent, said di-propylene glycol benzoate is present in a range of from 5 to 40 percent, said 1,4-cyclohexane di-methanol di-benzoate is present in the range of from 5 to 40 percent, said ethoxylated alcohol is present in a range of from 5 to 40 percent, said sulfo-polyester is present in a range of from 5 to 80 percent, said poly(vinyl) pyrrolidone vinyl acetate is present in a range of from 5 to 40 percent, and said anti-oxidants are present in the range of less than 1 percent.
6. The depilatory in accordance with claim 5 wherein the preferred water soluble adhesive is comprised of hydrogenated rosin in the percentage amount of 9.5 percent; di-propylene glycol benzoate in the percentage amount of 27 percent, di-methanol 1,4-cyclohexane di-benzoate in the percentage amount of 5 percent, ethoxylated alcohol in the percentage amount of 12.5 percent, water soluble sulfo-polyester in the percentage amount of 36.50 percent, poly(vinyl) pyrrolidone vinyl acetate in the percentage amount of 8.5 percent, and anti-oxidants in the percentage amount of 1 percent.