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Romeo lifts Big Chill past Cagayan Valley
Mar Villahermosa shot 19 of his 21 points in the second half and Terrence Romeo nailed the marginal basket as Big Chill nipped Cagayan Valley, 93-92, yesterday in the PBA D-League Foundation Cup at Filoil Flying V Arena in San Juan.
Villahermosa, who combined for nine triples with Mac Montilla, helped the Superchargers wrest the lead, 88-79, and Romeo scored on a layup that gave the Superchargers a 93-90 edge with seven seconds left after the Rising Suns had threatened at, 90-91.
"When Cagayan was making its run, we were rattled for a while but we were able to regain our composure," coach Robert Sison said after his Superchargers foiled the Rising Suns' bid to grab a share of the top spot.
In other games, Cebuana Lhuillier dumped Informatics, 101-76, to improve to third at 4-2, while Boracay Rum survived a huge run by newcomer Hog's Breath Cafe and escaped with a 72-68 victory.
Before Romeo's game-clincher, the Rising Suns blew a chance to take the lead when Chris Exciminiano missed an easy layup with over 10 seconds left.
The Rising Suns, who fell into a tie with the Superchargers at 3-2, missed another chance to forge overtime time when Mark Bringas' three-point attempt fell short. Adrian Celada scored an inconsequential basket at the buzzer for the final tally.
Montilla had 13 of his 18 points in the second half, while Romeo and Janus Lozada wound up with 14 each.
June Dizon had 14 points to lead seven Cebuana players in double figures.
Roider Cabrera pumped in 20 points to lead the Waves, who picked up their fourth win in seven games after surviving the Razorback's furious 23-7 rally in the closing minutes.
The scores:
First Game
BIG CHILL 93—Villahermosa 21, Montilla 18, Romeo 14, Lozada 14, Canlas 13, Heruela 4, Bringas 4, Holstein 2, Santos 2, Nuyles 1.
CAGAYAN VALLEY 92—Bringas 26, Webb 19, Poligrates 14, Exciminiano 12, Cruz 10, Celada 7, Canta 2,Melano 2, Montemayor 0, Del Rio 0.
Quarters: 18-15, 44-33, 71-62, 93-92
Second Game
CEBUANA LHUILLIER 101—Dizon 14, Bautista 13, Aguilar 12, Martinez 11, Banal 10, Zamar 10, Lopez 10, Bustos 10, Padilla 8, Buensuceso 2, Sarangay 2, Montecastro 0, Chiu 0, Custodio 0.
INFORMATICS 76—Teng 26, Mabayo 13, Altamrinao 10,Benitez 6, Cabonce 5, Ablaza 4, Acuña 4, Montano 4, Acidre 4, Morales 0, Labis 0, Bartolo 0, Matute 0.
Quarters: 29-8, 55-27, 78-48, 101-76
Third Game
BORACAY RUM 72—Cabrera 20, Sabellina 17, Viernes 8, Acibar 6, Taha 6, Bandaying 5, Siruma 3, Eguilos 2, Rosopa 2, Ilagan 2, Arellano 1, Tagarda 0, Monteclaro 0.
HOG'S BREATH CAFE 68—Belorio 15, Roy 11, Cayabyab 9, Eman 8, Lima 7, Pangilinan 5, Malinao 4, Morillo 4, Macasaet 3, Pacquiao 2, Rabalo 0, Armisen 0.
Quarters: 12-11, 33-28, 56-41, 72-68
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ANACORTES, Wash. - Thick black smoke rose from a fire at the Tesoro refinery in Anacortes on Wednesday afternoon, but there was no emergency.
A number of people called KING 5, concerned about the smoke.
The Tesoro Anacortes Refinery said early Wednesday afternoon they experienced an unexpected shutdown of three boilers that produce the majority of the refinery's steam.
The loss of steam required a number of process units to be temporarily shut down and process gases were temporarily diverted to the flare safety relief system.
The flare system is designed to handle this type of event and is working properly to safely burn-off the excess gas, said John McDarment, Manager Human Resources. Smoke that was observed was due to burning off of gases at the flare and was not associated with a fire at the facility. All personnel are accounted for and there are no injuries associated with the event. Tesoro takes pride in being a good neighbor in the community. We apologize for any inconvenience this may have caused.

subset: commoncrawl


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Elizabeth Luna
Elizabeth Luna, 6 months old, passed away Sunday, December 16, 2012.
Funeral services will be held at 2 p.m. Thursday, December 20, 2012, at Jan Lee Baptist Church with Rev. Mark Simons, officiating. Interment will follow in Burkburnett Memorial Cemetery under the direction of Owens & Brumley Funeral Home of Burkburnett.
Elizabeth was born May 20, 2012, in Wichita Falls, Texas, to Eric Luna and Amanda Michael. Heaven needed another angel, so God took ours.
She is survived by her parents, Amanda Michael and Eric Luna; two brothers, Darren Luna and Jace Luna, all of Wichita Falls; maternal grandparents, Mark and Sandra Michael, and Susan Balis, all of Iowa Park; paternal grandparents, Mike and Melissa Luna of Burkburnett; maternal great-grandparents, Ed and Vickey Michael of California, Dawn Michael of Ohio, and Garry and Connie Balis of Church Point, Louisiana; paternal great-grandparents, Frances Luna of Burkburnett, Dennis Cauble of Carrollton; aunts and uncles, Derek and Miranda Michael of Grapevine, Brett Michael of Iowa Park, Tabitha and James Skelnik of Chicago, Illinois, and Joshua Luna of Burkburnett; and numerous cousins.
The family will receive friends from 7 until 8 p.m. Wednesday, December 19, 2012, at Owens & Brumley Funeral Home of Burkburnett.
Condolences may be sent to the family at www.owensandbrumley.com.
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Mon-Fri: 7am-1am EST / Sat-Sun: 7am-11pm EST
ApplianceFrigidaire Refrigerator
Level of DifficultyA Bit Difficult
Time to do repair30 - 60 mins
Age of Appliance1 - 4 years
PliersScrew drivers
0 out of 4 people found this instruction helpful
First I removed the two screws that hold the frame in place. Then I had to unscrew the board and pull the plugs so that the actuator could be installed. The most difficult part was to re-insert the water tube in its place. There is very little space. I used long nose pliers to push the tube through. You have to be careful not to touch the electrical board b/c it can shock you. After I replaced the frame, everything worked just fine.
Help other customers find the most helpful instructions.
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Part Number: PS1526418
All brand logos are trademarks of their respective owners.
The PartSelect logo is a Registered Trademark of Atlantic Laundry Centres, Ltd.
Copyright © 1999-2015 , Eldis Group Partnership. All rights reserved.


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CONTEST: Meow Like a Pirate Day!
Avast ye mateys! Unless ye be wantin' to walk the plank, it's time to don yer best pirate garb and Meow Like a Pirate this Saturday!
The Cat's Meow will set sail for a raucous day of pillagin' and keel-haulin', so join in the fun!
Photoshopped pirate garb is purrmitted for those of you who are accustomed to going commando.
All ye kittehs, decorate your blogs or Catster profiles, and don your best pirate gear for The Cat's Meow's Meow Like a Pirate Contest!
Leave a comment on this post, and a link to your Catster profile and/or blog.
- All cats with a Catster Profile or public blog may enter.
- All cats in a household may enter.
- If more than one cat in the household is a finalist, the household will have only one entry in the grand prize drawing. (For example, if three of the ten finalists are from the same household, they will get one consolidated entry in the drawing for the grand prize, such that there will be eight names [7 individuals and 1 household] in the drawing.)
Leave your comment by 11:59pm Catster time (PT) on Sep 18th to be eligible.
We'll be givin' away 50 zealies and a kitty kat pirate hat (right) to the Top Pirate. The best entries will be featured on The Cat's Meow Blog on Saturday.
The best of the entries will be featured on The Cat's Meow on Saturday, Sep 19th. At the end of the day, a name will be drawn at random (via random.org) from those finalists for the Grand Prize winner.
Join the Pirate Purrade on Catster
Catsters, don't furget to tag your photos with "pirate" to join the Meow Like a Pirate Gallery!


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A biodegradable polymer comprising a condensation polymer of glycerol and a diacid. The polymer may be adapted for use as a tissue engineering construct. For example, it may be seeded with cells or molecules may be attached to it to modify the metabolism and proliferation of cells or to modify the degradation rate and/or mechanism of the polymer. The polymer may also be exploited in a variety of medical and non-medical applications.
1. A biocompatible, biodegradable elastomeric crosslinked polymer comprising glycerol and a diacid, wherein the polymer has a cross-link density of 1% up to less than about 40%, which can be obtained by polycondensation and crosslinking of glycerol and diacid at 120° C. under an inert atmosphere with reduction in pressure for 24 to 48 hours until the desired crosslinking is reached.
2. The polymer of
3. The polymer of
4. The polymer of
5. The polymer of
6. The polymer of
7. The polymer of
8. The polymer of
9. The polymer of
10. The polymer of
11. The polymer of
12. The polymer of 11, wherein the polymer has a cross-link density of less than 10%.
13. The polymer of
14. The polymer of
15. The polymer of
16. The polymer of
17. The polymer of
18. The polymer of
19. The polymer of
20. The polymer of
21. The polymer of
22. The polymer of
23. The polymer of
24. The polymer of
25. The polymer of
26. The polymer of
27. The polymer of
28. The polymer of
29. The polymer of
30. The polymer of
31. The polymer of
32. The polymer of
33. A stent, comprising the polymer of
34. The stent of
35. The stent of
36. A stent, comprising:
the polymer of
a second polymer
wherein the two polymers are combined in a mixture or adduct.
37. The stent of
38. The stent of
39. The stent of
40. A method of producing a polymer, comprising:
combining glycerol and a diacid to form a mixture; holding the mixture under conditions equivalent to a temperature of 120° C. in an inert atmosphere at a pressure of 1 Torr to 40 mTorr until the mixture forms a crosslinked polymer having a pre-determined crosslinking density of 1% up to less than about 40%.
41. The method of
42. The method of
43. The method of
44. The method of
45. The method of
46. The method of
47. The method of
providing a substrate having a predetermined pattern of grooves and channels and a sacrificial coating of a water-soluble material;
after the step of combining, casting the mixture over the substrate; and
after the mixture has the predetermined cross-link density, dissolving the sacrificial layer to free the polymer from the substrate,
wherein the polymer has a relief pattern corresponding to the predetermined pattern.
48. The method of
49. The method of
50. The method of
51. The method of
combining glycerol and a diacid to form a mixture;
holding the mixture at a temperature of 120° C. in an inert atmosphere at a pressure of 1 Torr for 24 hours; and
holding the mixture at a temperature of 120° C. in an inert atmosphere at a pressure of 1 Torr until the polymer has a predetermined cross-link density.
52. The polymer of
53. The polymer of
54. The polymer of
This application claims the priority of Provisional Patent Applications Nos. 60/340,432, filed Oct. 22, 2001, and 60/336,545, filed Oct. 23, 2001, the entire contents of which are incorporated by reference herein.
The work described herein was supported, in part, by a grant from the National Institutes of Health (#5-R01-HL60435-02). Accordingly, the Government may have certain rights in this invention.
Biodegradable polymers have significant potential in various fields of medicine, such as tissue engineering, drug delivery, and in vivo sensing. Many biomedical devices are implanted in a mechanically dynamic environment in the body, which requires the implants to sustain and recover from various deformations without mechanical irritation of the surrounding tissue. In many cases, the matrices and scaffolds of these implants would ideally be made of biodegradable polymers that mimic the functions of extracellular matrix (ECM), a soft, tough and elastomeric proteinaceous network that provides mechanical stability and structural integrity to tissues and organs. Hence an elastomeric biodegradable polymer that readily recovers from relatively large deformations is advantageous for maintaining the implant's proper function (Peppas, N. A., et al., New Challenges In Biomaterials. Science 263: 1715-20, 1994; Langer, R., Biomaterials: Status, Challenges and Perspectives. AIChE J. 46: 1286-1289, 2000). However, most currently available biodegradable polymers are not elastomeric, and >95% of the revenue from these polymers is generated by bioabsorbable sutures. For example, PLGA has a modulus of 2 GPa and a maximum elongation of about 2-10%. In contrast, the modulus of collagen is 1.2 GPa, and the modulus of elastin is 410 kPa. Common biodegradable polymers often require surface modification for wettability and cell attachment (Gao, J., Niklason, et al., Surface Hydrolysis of Poly(glycolic acid) Meshes Increases the Seeding Density of Vascular Smooth Muscle Cells. J. Biomed. Mater. Res. 42: 417-424, 1998) and are subject to fibrous encapsulation (Anderson, J. M., et al., Biodegradation and Biocompatibility of PLA and PLGA Microspheres. Adv. Drug Deliv. Rev. 28: 5-24, 1997; Anderson, J. M., In vivo Biocompatibility of Implantable Delivery Systems and Biomaterials. Eur. J Pharm. Biopharm. 40: 1-8 1994).
In one aspect, the invention is a polymer comprising a biodegradable condensation polymer of glycerol and a diacid. The polymer has a tensile elastic modulus of 5 MPa or less. The polymer may be biocompatible, elastomeric, or both. The ratio of the glycerol to the diacid may be between 1 and 1.5. The diacid may be sebacic acid. Alternatively, the diacid may have fewer carbons, for example, between 3 and 9 carbon atoms. Longer diacids, having chains longer than 10, 15, 20, or 25 carbon atoms, may also be used. The diacid may include one or more double bonds, and aromatic group, an amine, a hydroxyl group, a halogen atom, an aliphatic side chain, or any combination of the above. The polymer may be crosslinked. The polymer may have a crosslink density of 40% or less, less than 30%, less than 20%, less than 20%, less than 5%, less than 1%, less than 0.5%, or less than 0.05%. The Young's modulus of the polymer may be less than 3 MPa, less than 1 MPa, less than 0.5 MPa, less than 0.1 MPa, or less than 0.01 MPa. The ultimate tensile strength of the polymer may be greater than 0.5 MPa. The polymer may have a maximum elongation greater than 250%. When the polymer is exposed to an aqueous environment, it may be characterized by surface erosion.
The polymer may further include a biomolecule, a hydrophilic group, a hydrophobic group, a non-protein organic group, an acid, a small molecule, a bioactive agent, or any combination of the above. For example, the biomolecule may be a growth factor, cell adhesion sequence, polynucleotide, polysaccharide, polypeptide, extracellular matrix component, or any combination of these. These molecular groups may be linked to the polymer through a covalent bond or a non-covalent bond, e.g., a hydrogen bond, an electrostatic interaction, a hydrophobic interaction, or a van der Waals interaction.
The polymer may be seeded with cells, for example, connective tissue cells, organ cells, muscle cells, nerve cells, or some combination of these. In another embodiment, the polymer may further comprise a second polymer as a mixture or adduct. The second polymer may be biodegradable or non-biodegradable, and it may be biocompatible.
A chromophore may be covalently linked to the polymer. A receptor may be covalently linked to the chromophore or interposed between the chromophore and the polymer. The polymer may be porous and may include a porogen. The shape of the polymer may be particulate, a tube, a sphere, a strand, a coiled strand, a capillary network, a film, a fiber, a mesh, or a sheet. In another aspect, the invention is a polymer comprising a biodegradable, elastomeric condensation polymer of glycerol and a diacid. In another embodiment, the invention is a polymer comprising a biodegradable condensation polymer of glycerol and a diacid, wherein the polymer is adapted and constructed for use as an adhesive.
In another aspect, the invention is a drug delivery device comprising the glycerol-diacid co-polymer and a small molecule, a bioactive molecule, or both. The small or bioactive molecule may be covalently or non-covalently attached to the polymer. The drug delivery device may be adapted to be implanted in the abdominal region of a patient, and the small or bioactive molecule may be an anti-inflammatory agent.
In another aspect, the invention is a cardiac stent comprising an expandable metal mesh and the glycerol-diacid co-polymer or a mixture or adduct of the co-polymer and a second biocompatible polymer. Both the coated stent and the polymeric stent may include a small molecule or a bioactive agent disposed within the polymer, for example, covalently or non-covalently linked to the polymer. The second biocompatible polymer may be biodegradable or non-biodegradable.
In another aspect, the invention is an absorbent garment including a liquid pervious topsheet, a backsheet comprising the glycerol-diacid co-polymer, and a liquid absorbent cord disposed between the topsheet and the backsheet. The polymer may be degradable in a landfill, and the garment may be a diaper, incontinence protector, sanitary napkin, panty liner, or surgical dressing.
In another aspect, the invention is a chewing gum including the glycerol-diacid co-polymer and a flavoring agent, colorant, or both. The chewing gum may further include a small molecule, a nutrient, or both that may be covalently or non-covalently attached to the polymer.
In another embodiment, the invention is an inflatable balloon that includes the glycerol-diacid co-polymer and that is degradable in an outdoor environment. In another embodiment, the invention is a fishing lure or a fishing fly that includes the glycerol-diacid co-polymer and a hook; the polymer degrades after exposure to an aqueous environment. In another embodiment, the invention is a disposable bag including the glycerol-diacid co-polymer. The disposable bag degrades in a landfill.
In another aspect, the invention is a tissue engineering construct including an elastomeric biodegradable condensation polymer of glycerol and a diacid. The ratio of the glycerol to the diacid may be between 1 and 1.5. The diacid may be sebacic acid. Alternatively, the diacid may have carbon chains having fewer or more carbon atoms, for example, between 3 and 9 carbons, greater than 10 carbons, greater than 15 carbons, greater than 20 carbons, or greater than 25 carbons.
The polymer may have a crosslink density of 40% or less, less than 30%, less than 20%, less than 20%, or less than 5%. The Young's modulus of the polymer may be less than 5 MPa, 3 MPa, less than 1 MPa, less than 0.5 MPa, less than 0.1 MPa, or less than 0.01 MPa. The ultimate tensile strength of the polymer may be greater than 0.5 MPa. The polymer may have a maximum elongation greater than 250%. When the polymer is exposed to an physiological environment, it may be characterized by surface erosion.
The tissue may be selected from muscle tissue, connective tissue, nerve tissue, organ tissue, epithelial tissue, or any combination of these. For example, the tissue may be skin, lung, cardiac muscle, skeletal muscle, smooth muscle, heart valve, bone, nerve, kidney, bladder, liver, tendon, ligaments, or pancreas tissue.
The construct may be seeded with connective tissue cells, organ cells, muscle cells, nerve cells, or some combination of these. For example, the cells may be tenocytes, fibroblasts, ligament cells, endothelial cells, lung cells, epithelial cells, smooth muscle cells, cardiac muscle cells, skeletal muscle cells, islet cells, nerve cells, hepatocytes, kidney cells, bladder cells, urothelial cells, chondrocytes, or bone-forming cells.
The shape of the polymer may be particulate, a tube, a sphere, a strand, a coiled strand, a capillary network, a film, a fiber, a mesh, or a sheet. The polymer may be porous, and the tissue engineering construct may include a porogen.
The construct may further include a biomolecule, a hydrophilic group, a hydrophobic group, a non-protein organic group, an acid, a small molecule, a bioactive molecule, or some combination of these. The construct may further include a second biocompatible polymer that may form a mixture or adduct with the biocompatible condensation polymer. The second biocompatible polymer may be biodegradable or non-biodegradable.
In another aspect, the invention is a method of producing a polymer. The invention includes the steps of combining equal molar amounts of glycerol and a diacid to form a mixture, holding the mixture at a temperature of 120° C. in an inert atmosphere at a pressure of 1 Torr for 24 hours, and holding the mixture at a temperature of 120° C. and a pressure of 40 m Torr until the mixture forms a polymer having a predetermined cross-link density. The mixture may be held at 40 m Torr for 24 hours or 48 hours. The step of combining may further include adding a porogen, e.g., azodicarboimide, an alkali halide salt, or a water-soluble salt, to the mixture. The polymerized mixture may be soaked in water to leach out the porogen. The method may further include modifying hydroxyl groups on the polymer with one or more of a biomolecule, a hydrophilic group, a hydrophobic group, a non-protein organic group, an acid, a small molecule, or a bioactive agent.
The method may further include the steps of providing a substrate having a predetermined pattern of grooves and channels and a sacrificial coating of a water-soluble material, casting the mixture over the substrate after the step of combining, and, after the mixture has the predetermined cross-link density, dissolving the sacrificial layer to free the polymer from the substrate. The polymer has a release pattern corresponding to the predetermined pattern. The release pattern in the polymer may be covered to form covered channels. For example, the cover may include an elastomeric copolymer of glycerol and a diacid. The step of covering may include providing a cover, disposing a partially polymerized equimolar mixture of glycerol and a diacid between the cover and the polymer, and cross-linking the equimolar mixture. A cover may also be provided by combining equal molar amounts of glycerol and a diacid to form a mixture, holding the mixture at a temperature of 120° C. in an inert atmosphere at a pressure of 1 Torr for 24 hours, forming the mixture into a sheet, disposing the sheet over the relief pattern in the polymer, and holding the mixture at a temperature of 120° C. in an inert atmosphere at a pressure of 1 Torr until the sheet has a predetermined cross-link density. The mixture may be formed into a sheet before or after the initial holding step.
"Biomolecules": The term "biomolecules", as used herein, refers to molecules (e.g., proteins, amino acids, peptides, polynucleotides, nucleotides, carbohydrates, sugars, lipids, nucleoproteins, glycoproteins, lipoproteins, steroids, etc.) whether naturally-occurring or artificially created (e.g., by synthetic or recombinant methods) that are commonly found in cells and tissues. Specific classes of biomolecules include, but are not limited to, enzymes, receptors, neurotransmitters, hormones, cytokines, cell response modifiers such as growth factors and chemotactic factors, antibodies, vaccines, haptens, toxins, interferons, ribozymes, anti-sense agents, plasmids, DNA, and RNA.
"Biocompatible": The term "biocompatible", as used herein is intended to describe materials that do not elicit a substantial detrimental response in vivo.
"Biodegradable": As used herein, "biodegradable" polymers are polymers that degrade fully (i.e., down to monomeric species) under physiological or endosomal conditions. In preferred embodiments, the polymers and polymer biodegradation byproducts are biocompatible. Biodegradable polymers are not necessarily hydrolytically degradable and may require enzymatic action to fully degrade.
"Elastomer": As used herein, an elastomer is a macromolecular material can return rapidly to the approximate shape from which it has been substantially distorted by a weak stress. Rubber is the most common elastomer.
"Endosomal conditions": The phrase "endosomal conditions", as used herein, relates to the range of chemical (e.g., pH, ionic strength) and biochemical (e.g., enzyme concentrations) conditions likely to be encountered within endosomal vesicles. For most endosomal vesicles, the endosomal pH ranges from about 5.0 to 6.5.
"Physiological conditions": The phrase "physiological conditions", as used herein, relates to the range of chemical (e.g., pH, ionic strength) and biochemical (e.g., enzyme concentrations) conditions likely to be encountered in the intracellular and extracellular fluids of tissues. For most tissues, the physiological pH ranges from about 7.0 to 7.4.
"Polynucleotide", "nucleic acid", or "oligonucleotide": The terms "polynucleotide", "nucleic acid", or "oligonucleotide" refer to a polymer of nucleotides. The terms "polynucleotide", "nucleic acid", and "oligonucleotide", may be used interchangeably. Typically, a polynucleotide comprises at least three nucleotides. DNAs and RNAs are polynucleotides. The polymer may include natural nucleosides (i.e., adenosine, thymidine, guanosine, cytidine, uridine, deoxyadenosine, deoxythymidine, deoxyguanosine, and deoxycytidine), nucleoside analogs (e.g., 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3-methyl adenosine, C5-propynylcytidine, C5-propynyluridine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5-methylcytidine, 7-deazaadenosine, 7-deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, O(6)-methylguanine, and 2-thiocytidine), chemically modified bases, biologically modified bases (e.g., methylated bases), intercalated bases, modified sugars (e.g., 2′-fluororibose, ribose, 2′-deoxyribose, arabinose, and hexose), or modified phosphate groups (e.g., phosphorothioates and 5′-N-phosphoramidite linkages).
"Polypeptide", "peptide", or "protein": According to the present invention, a "polypeptide", "peptide", or "protein" comprises a string of at least three amino acids linked together by peptide bonds. The terms "polypeptide", "peptide", and "protein", may be used interchangeably. Peptide may refer to an individual peptide or a collection of peptides. Inventive peptides preferably contain only natural amino acids, although non-natural amino acids (i.e., compounds that do not occur in nature but that can be incorporated into a polypeptide chain; see, for example, http://www.cco.caltech.edu/˜dadgrp/Unnatstruct.gif, which displays structures of non-natural amino acids that have been successfully incorporated into functional ion channels) and/or amino acid analogs as are known in the art may alternatively be employed. Also, one or more of the amino acids in an inventive peptide may be modified, for example, by the addition of a chemical entity such as a carbohydrate group, a phosphate group, a farnesyl group, an isofarnesyl group, a fatty acid group, a linker for conjugation, functionalization, or other modification, etc. In a preferred embodiment, the modifications of the peptide lead to a more stable peptide (e.g., greater half-life in vivo). These modifications may include cyclization of the peptide, the incorporation of D-amino acids, etc. None of the modifications should substantially interfere with the desired biological activity of the peptide.
"Polysaccharide", "carbohydrate" or "oligosaccharide": The terms "polysaccharide", "carbohydrate", or "oligosaccharide" refer to a polymer of sugars. The terms "polysaccharide", "carbohydrate", and "oligosaccharide", may be used interchangeably. Typically, a polysaccharide comprises at least three sugars. The polymer may include natural sugars (e.g., glucose, fructose, galactose, mannose, arabinose, ribose, and xylose) and/or modified sugars (e.g., 2′-fluororibose, 2′-deoxyribose, and hexose).
"Small molecule": As used herein, the term "small molecule" is used to refer to molecules, whether naturally-occurring or artificially created (e.g., via chemical synthesis), that have a relatively low molecular weight. Typically, small molecules are monomeric and have a molecular weight of less than about 1500 g/mol. Preferred small molecules are biologically active in that they produce a local or systemic effect in animals, preferably mammals, more preferably humans. In certain preferred embodiments, the small molecule is a drug. Preferably, though not necessarily, the drug is one that has already been deemed safe and effective for use by the appropriate governmental agency or body. For example, drugs for human use listed by the FDA under 21 C.F.R. §§330.5, 331 through 361, and 440 through 460; drugs for veterinary use listed by the FDA under 21 C.F.R. §§500 through 589, incorporated herein by reference, are all considered acceptable for use in accordance with the present invention.
"Bioactive agents": As used herein, "bioactive agents" is used to refer to compounds or entities that alter, inhibit, activate, or otherwise affect biological or chemical events. For example, bioactive agents may include, but are not limited to, anti-AIDS substances, anti-cancer substances, antibiotics, immunosuppressants, anti-viral substances, enzyme inhibitors, neurotoxins, opioids, hypnotics, anti-histamines, lubricants, tranquilizers, anti-convulsants, muscle relaxants and anti-Parkinson substances, anti-spasmodics and muscle contractants including channel blockers, miotics and anti-cholinergics, anti-glaucoma compounds, anti-parasite and/or anti-protozoal compounds, modulators of cell-extracellular matrix interactions including cell growth inhibitors and anti-adhesion molecules, vasodilating agents, inhibitors of DNA, RNA or protein synthesis, anti-hypertensives, analgesics, anti-pyretics, steroidal and non-steroidal anti-inflammatory agents, anti-angiogenic factors, anti-secretory factors, anticoagulants and/or antithrombotic agents, local anesthetics, ophthalmics, prostaglandins, anti-depressants, anti-psychotic substances, anti-emetics, and imaging agents. In certain embodiments, the bioactive agent is a drug.
A more complete listing of bioactive agents and specific drugs suitable for use in the present invention may be found in "Pharmaceutical Substances: Syntheses, Patents, Applications" by Axel Kleemann and Jurgen Engel, Thieme Medical Publishing, 1999; the "Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals", Edited by Susan Budavari et al., CRC Press, 1996, and the United States Pharmacopeia-25/National Formulary-20, published by the United States Pharmcopeial Convention, Inc., Rockville Md., 2001, all of which are incorporated herein by reference.
"Tissue"; as used herein, the term "tissue" refers to a collection of similar cells combined to perform a specific function, and any extracellular matrix surrounding the cells.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
The invention is described with reference to the several figures of the drawing, in which,
Collagen and elastin are the major fibrous protein components of ECM. Collagen provides mechanical strength to ECM, while elastin adds rubber-like elasticity to certain ECM, such as those in the lungs, ligaments, and arteries (Matthews, C. K., et al., Biochemistry. The Benjamin/Cummings Publishing Company, Redwood City, 1990; Voet, D., et al., Biochemistry. John Wiley & Sons, Inc., New York, 1995). Both collagen and elastin are unusual proteins that are covalently cross-linked (
Collagen fibers can sustain deformations of ˜20% (Fratzl, P., et al., Fibrillar Structure and Mechanical Properties of Collagen. J. Struct. Biol. 122: 119-22 (1998); Wang, J. L., et al. Failure Criterion of Collagen Fiber: Viscoelastic Behavior Stimulated by Using Load Control Data. Theor. Appl. Fract. Mech. 27: 1-12, 1997), far greater than the most prevalent biodegradable polymers, poly(lactide), poly(glycolide) and their copolymers (PLGA) (Storey, R. F., et al., Methacrylate-endcapped Poly(D,L-lactide-co-trimethylene carbonate) Oligomers. Network Formation by Thermal Free-radical curing. Polymer 38: 6295-6301, 1997; Helminen, A., et al., Biodegradable Cross-linked Polymers Based on Triethoxysilane Terminated Polylactide Oligomers. Polymer 42: 3345-3353, 2001). The recoverable deformation is also greater than that of poly-4-hydroxybutyrate (P4HB), which is about 10%.
Based on the structural elements of collagen and elastin, we hypothesized that: (1) good mechanical properties could be obtained through covalent cross-linking (Lee, K. Y., et al., Controlling Mechanical and Swelling Properties of Alginate Hydrogels Independently by Cross-Linker Type and Cross-Linking Density. Macromolecules 33: 4291-4294, 2000; Anseth, K. S., et al. Photopolymerizable Degradable Polyanhydrides with Osteocompatibility. Nat. Biotechnol. 17: 156-9, 1999; Nagata, et al., Biodegradability of Poly(Ethylene Terephthalate) Copolymers with Poly(Ethylene Glycol)s and Poly(Tetramethylene Glycol). Polym. Int. 39: 83-9, 1996) of polymers and hydrogen bonding of hydroxyl groups; and (2) rubber-like elasticity could be obtained by building a three-dimensional network of random coils through copolymerization where at least one monomer is trifunctional (Erman, 1994).
To realize this design, we considered the following criteria: (1) degradation mechanism—we chose hydrolysis over enzymatic degradation, as enzyme level varies among individuals and enzymatic activities vary with time even for the same person (Langer, 2000); (2) hydrolysable chemical bond—we chose ester for its established and versatile synthetic methods (March, J. Advanced Organic Chemistry. John Wiley & Sons, Inc., New York, 1992); (3) cross-link density—low density is preferred, as high degree of cross-linking usually leads to rigid and brittle polymers; and (4) specific monomers—they should be non-toxic, at least one should be trifunctional and at least one should provide hydroxyl groups for hydrogen bonding.
Glycerol [CH2(OH)CH(OH)CH2OH], the basic building block for lipids, satisfies all three requirements and was chosen as the alcohol monomer (
Other diacids of different lengths, including malonic acid [HOOC(CH2)COOH] and succinic acid [HOOC(CH2)2COOH] up to long chain fatty acid dimers, may also be used to form elastomeric biomaterials according to the invention. Exemplary diacids include glutaric acid (5 carbons), adipic acid (6 carbons), pimelic acid (7 carbons), suberic acid (8 carbons), and azelaic acid (nine carbons). Exemplary long chain diacids include diacids having more than 10, more than 15, more than 20, and more than 25 carbon atoms. Non-aliphatic diacids may be used. For example, versions of the above diacids having one or more double bonds may be employed to produce glycerol-diacid co-polymers. Amines and aromatic groups may also be incorporated into the carbon chain. Exemplary aromatic diacids include terephthalic acid and carboxyphenoxypropane. The diacids may also include substituents as well. Reactive groups like amine and hydroxyl will increase the number of sites available for cross-linking. Amino acids and other biomolecules will modify the biological properties of the polymer. Aromatic groups, aliphatic groups, and halogen atoms will modify the inter-chain interactions within the polymer.
Elastomeric glycerol-diacid copolymers of the invention are also referred to as bio-rubber due to their biodegradability and elasticity. Most of the hydroxyl groups in collagen are from hydroxyproline, while the hydroxyl groups in bio-rubber are from non-cross-linked glycerol. The cross-links in bio-rubber can be oligomeric as well. We anticipated this biomimetic approach would yield biodegradable polymers with improved mechanical properties and biocompatibility.
In a preferred embodiment, the glycerol-diacid copolymers of the invention have a tensile elastic modulus of 5 MPa or less. One skilled in the art will recognize that the modulus of the polymer may be adjusted depending on the application. For example, the polymer may have a modulus less than 3 MPa, less than 1 MPa, less than 0.5 MPa, less than 0.3 MPa, or less than 0.1 MPa.
The elastic modulus and degradation rate of the polymer is easily adjusted by modifying the cross-link density. In certain embodiments, the cross-link density of elastomeric polymers produced according to the invention may be 40% or less, less than 30%, less than 20%, less than 10%, or less than 5%.
Synthesis and Analysis
PGS was synthesized by polycondensation of 0.1 mole each of glycerol (Aldrich, Milwaukee, Wis.) and sebacic acid (Aldrich) at 120° C. under argon for 24 h before the pressure was reduced from 1 Torr to 40 mTorr over 5 h. The reaction mixture was kept at 40 mTorr and 120° C. for 48 h. Polycondensation of glycerol and sebacic acid yields a transparent, almost colorless elastomer that does not swell or dissolve in water. Alternate methods have been used to synthesize rigid, totally cross-linked polymers of glycerol and sebacic acid with a molar ratio of glycerol to sebacic acid of 2:3 (Nagata, 1999).
Preferred molar ratios for glycerol-diacid co-polymers produced according to the invention range from 1:1 to 1:1.5. Catalysts may be used to reduce reaction temperature, shorten reaction time, and increase individual chain length. However, the catalyst should be bio-compatible or easily removed. An exemplary FDA-approved catalyst is stannous octoate (bis(2-ethylhexanoate)tin(II)), available from Fluka and Strem.
A KBr pellet of newly prepared PGS was used for FTIR analysis on a Nicolet Magna-IR 550 Spectrometer. A Perkin-Elmer DSC differential scanning calorimeter was used for DSC measurements. Elemental analysis on vacuum-dried samples was performed by QTI Inc. (Whitehouse, N.J.). The water-in-air contact angle was measured at room temperature using the sessile drop method and an image analysis of the drop profiled with VCA2000 video contact angle system on slabs of polymer fixed on glass slides.
Chemical analysis indicates that the polymerization reaction has a yield of close to 100%. For example, the FTIR spectrum does not show a carbonyl stretch for a free carboxylic acid group (
Elemental analysis confirms the composition of the PGS as approximately 1 glycerol:1 sebacic acid (calculated for C13H22O5. C: calculated 60.47%, found 60.46%; H: calculated 8.53%, found 8.36%). The polymer is insoluble in water and swells 2.1+/−0.33% after soaking in water for 24 h. The polymer surface is very hydrophilic due to the hydroxyl groups attached to its backbone. Its water-in-air contact angle is 32.0°, almost identical to that of a flat 2.7 nm thick type I collagen film (31.9°) (See, Dupont-Gillain, et al., Collagen adsorption on poly(methyl methacrylate): net-like structure formation upon drying. Polym. Int. 48: 271-276, 1999).
The crosslinking density is expressed by n (moles of active network chains per unit volume), which is 38.3±3.40 mol/m3, and Mc, the relative molecular mass between crosslinks, which is 18,300±1,620, calculated from the following equation (See, Sperling, L. H., Introduction to Physical Polymer Science, John Wiley & Sons, New York; 1992):
Differential scanning calorimetery (DSC) showed two crystallization temperatures at −52.14° C. and −18.50° C., and two melting temperatures at 5.23° C. and 37.62° C. No glass transition temperature was observed above −80° C., which is the lower detection limit of the instrument. The DSC results indicate that the polymer is totally amorphous at 37° C.
Similar to vulcanized rubber, this elastomer is a thermoset polymer. However, the uncrosslinked prepolymer can be processed into various shapes because it can be melted into liquid and is soluble in common organic solvents, such as 1,3-dioxolane, tetrahydrofuran, ethanol, isopropanol, and N,N-dimethylformamide. We have prepared PGS sheets and foams with these methods. Briefly, a mixture of NaCl particles of appropriate size and an anhydrous 1,3-dioxolane solution of the prepolymer was poured into a PTFE mold. One skilled in the art will recognize that other salts besides NaCl may also be employed. The polymer was cured in the mold in a vacuum oven at 120° C. and 100 mtorr. A porous scaffold was obtained after salt leaching in deionized water. Alternative porogens include azodicarboimide, which decomposes into nitrogen, carbon dioxide, and ammonia upon heating, and other porogens known to those skilled in the art. The primary requirements for ionic porogens are solubility in water and non-interference with polymerization.
Mechanical Testing
Tensile tests on thin strips of PGS reveal a stress-strain curve characteristic of an elastomeric and tough material (
The non-linear shape of the tensile stress-strain curve is typical for elastomers and resembles those of ligament (Yamaguchi, S., Analysis of Stress-Strain Curves at Fast and Slow Velocities of Loading in vitro in the Transverse Section of the Rat Incisor Periodontal Ligament Following the Administration of Beta-aminopropionitrile. Arch. Oral Biol. 37: 439-44, 1992; Komatsu, K., et al., The Effect of Velocity of Loading on the Biomechanical Responses of the Periodontal Ligament in Transverse Sections of the Rat Molar in vitro. Arch. Oral. Biol. 38: 369-75, 1993; Chiba, M., et al., Mechanical Responses of the Periodontal Ligament in the Transverse Section of the Rat Mandibular Incisor at Various Velocities of Loading in vitro. J. Biomech. 26: 561-70, 1993) and vulcanized rubber (Nagdi, K. Rubber as an Engineering Material: Guideline for Users. Hansesr, Munich, 1993) (
Overall, P4HB has a much higher modulus (stiffer) and much lower strain to failure compared with either PGS or vulcanized rubber. The value of the Young's modulus of PGS is between those of ligaments (kPa scale) (Yamaguchi, 1992; Komatsu, 1993; Chiba, 1993), which contain a large amount of elastin in addition to collagen, and tendon (GPa scale) (Fratzl, 1998; Wang, 1997; Misof, K. et al., A new molecular model for collagen elasticity based on synchrotron X-ray scattering evidence. Biophys. J. 72:1376-1381, 1997), which is mainly made of collagen. The strain to failure of PGS is similar to that of arteries and veins (up to 260%) (Lee, M. C., et al., Strain rate effects on tensile failure properties of the common carotid artery and jugular veins of ferrets. J. Biomech. 25:925-927, 1992), and much larger than that of tendons (up to 18%) (Haut, R. C. The effect of a lathyritic diet on the sensitivity of tendon to strain rate. J. Biomech. Eng. 107:166-174, 1985). After soaking for 24 h in water, the weight of PGS barely changes, and the mechanical properties are virtually the same as dry polymer. Compression tests indicate that PGS can be compressed up to 70% repeatedly without rupture (
In Vitro Biocompatibility
The polymer appears to be biocompatible both in vitro and in vivo. Due to its elastomeric nature, bio-rubber may find applications in tissue engineering of soft tissues, especially muscle tissue, artery, and heart valves. In one study, we chose primary human aortic smooth muscle cells (HASMC) and primary human aortic endothelial cells (HAEC) to test the in vitro biocompatibility of the polymer. PGS samples were cut into approximately 10×10×0.2 mm slices, autoclaved at 120° C. for 20 min, and fixed in 6 wells of a 12-well plate (the polymer adheres easily to the surface with a slight pressure applied by a specula). Each well was filled with 2 ml of PBS and the solution was changed after 12 h. PBS was replaced by 2 ml of growth medium (Clonetics) 12 h later. After another 12 h, the media was removed and each well was charged with 1.75 ml of fresh medium. The plates were kept on a shaker in a 37° C. incubator during the above process. Each well was charged with 0.25 ml of single cell suspension (HASMC or HAEC, Clonetics), and the plate was put on a shaker at 40 rpm in a 37° C. incubator with 5% CO2. The media was changed after 24 h. Media exchange was performed every 48 h after that. At day 7, phase contrast images were taken for both the polymer wells and the control wells on a Nikon Diaphot microscope equipped with a Nikon 6000 camera. The trypsinized cells were counted by Tripan-blue exclusion on a hemocytometer.
The cells in the polymer wells had normal morphology and reached confluence within 7 days (
In a second experiment, nine glass Petri dishes (60 mm diameter) were coated with 1,3-dioxolane solution of PGS prepolymer (1%). The coated dishes were transferred into a vacuum oven after evaporation of the solvent in air. The prepolymer was crosslinked into the elastomer after 24 h at 120° C. and 120 mtorr. Nine control dishes were coated with 1% CH2Cl2 solution of PLGA (50:50, carboxyl ended, relative molecular mass 15,000 (Mr 15K), Boehringer Ingelheim, Ingelheim, Germany), and the solvent was evaporated for 24 h in air. The coated dishes were sterilized by UV radiation for 15 min. Each dish was soaked in growth medium for 4 h, replaced with fresh medium, and soaked for 4 h before cell seeding to remove any unreacted monomers or residual solvents. Each dish was seeded with 100,000 NIH 3T3 fibroblast cells and 8 ml of growth medium.
The cells were incubated at 37° C. with 5% CO2. Cell density was measured by MTT assay (Hansen, M. B., et al., Re-examination and further development of a precise and rapid dye method for measuring cell growth/cell kill. J. Immunol. Methods 119:203-210, 1989). Medium exchange was carried out every 48 h. At day 6, phase contrast images were taken for both the polymer wells and the control wells on a Zeiss Axiovert 200 microscope equipped with a Dage 240 digital camera. The cells in PGS sample wells were viable and adherent and showed normal morphology with higher growth rate than the control, as tested by MTI assay (Northup, S. J., et al., In Handbook of Biomaterials Evaluation, von Recum, A. F., ed, Taylor & Francis, Philadelphia, 325-339, 1999) (
In Vivo Biocompatibility
Subcutaneous implantation of the polymer in Sprague-Dawley rats was used to test its biocompatibility in vivo. Polymer slabs of approximately 5×5×2 mm were autoclaved before being implanted subcutaneously in 15 seven-week-old female Sprague-Dawley rats (Charles River Laboratories) by blunt dissection. The animals were cared for in compliance with the regulations of MIT and the principles of Laboratory Animal Care published by the National Institute of Health (National Institutes of Health, Principles of Laboratory Animal Care, NIH pub. no. 85-23, rev. 1985). Each animal received two implants in the abdominal area. Every implantation site was marked by two tattoo marks 2 cm away from the implantation center. The animals were randomly divided into five groups. The body weights of the animals were monitored regularly. At each predetermined time point (5, 12, 19, 31, 60 days), one group of rats was sacrificed, and tissue samples (˜15×15 mm) surrounding the implants were harvested with the intact implant. The samples were fixed in 10% formalin for 24 h. and embedded in paraffin after a series of dehydration steps in ethanol and xylenes. The slides were stained with hematoxylin and eosin (H&E) and Masson's trichrome stain (MTS).
At 5 days postimplantation, the skin sections contained a single well-demarcated pocket within the subcuticular adipose tissue separating the discrete muscle layers immediately underlying the dermis (
At 12 days, the zone of capillary proliferation and inflammation expanded modestly to approximately 50 μm in some areas while thinning in others. The pocket lining immediately adjacent to the implant showed a mild multifocal pattern of eosinophilic hyalinization with degeneration of some inflammatory cells (
At 19 days, the perilumenal zone was significantly reduced in size to 10-20 μm associated with small numbers of remaining capillaries and significant resolution of the inflammatory component (
At 31 days, the perilumenal zone was reduced to 5-10 μm of hyalinized sloughing debris with a capillary and collagen density (MTS) consistent with adjacent normal tissue (
At 60 days, the implantation sites were undetectable despite repeated sectioning of the specimens at multiple levels (
In summary, a modest focal inflammatory response was observed during the first 12 days after operation compared to healthy tissue from the same animal (
Subcutaneous implantation in Sprague-Dawley rats was also used to compare the in vivo biocompatibility of PGS and PLGA. Autoclaved PGS slabs of approximately 6×6×3 mm and ethylene oxide-sterilized PLGA (50:50, carboxyl ended, Mr 15K, Boehringer Ingelheim) disks (2 mm thick, 12.5 mm diameter) were implanted subcutaneously in 15 seven-week-old female Sprague-Dawley rats (Charles River Laboratories, Wilmington, Mass.) by blunt dissection under deep isoflurane-O2 general anesthesia. The surface area/volume ratio (1.33±0.04) was kept the same for both PGS and PLGA implants. Two implants each of PGS and PLGA were implanted symmetrically on the upper and lower back of the same animal. The animals were randomly divided into five groups. At each predetermined time point (7, 14, 21, 28, and 35 days), one group of rats was killed and tissue samples (˜15×15 mm) surrounding the implants were harvested with the intact implant. The implant sites were marked and the samples processed as described above. At each time point, 12 slides for each polymer were obtained. All histologic preparations were assessed by a pathologist who was not informed of the identity of the polymer implant in each slide. The thickness of the inflammatory zone (H&E) and collagen deposition (MTS) for each polymer implant is expressed as the average value of three readings per slide of six slides at each time point.
The inflammatory responses subsided with time for both polymer implants (
In the first three weeks, the inflammatory response of PLGA implantation sites was ˜16% thinner than that of PGS sites (
The inflammatory response and fibrous capsule formation observed for PLGA are similar to those reported in the literature (Cadee, J. A., et al., A comparative biocompatibility study of microspheres based on crosslinked dextran or poly(lactic-co-glycolic) acid after subcutaneous injection in rats. J. Biomed. Mater. Res., 56:600-609, 2001; van der Elst, et al., Bone Tissue response to biodegradable polymers used for intramedullary fracture fixation: a long-term in vivo study in sheep femora. Biomaterials., 20:121-128, 1999). Thick fibrous capsules block mass transfer between the implants and surrounding tissues, which an impair implant functions. Overall, the inflammatory response of PGS is similar to the PLGA. However, unlike PLGA, PGS induces little, if any, fibrous capsule formation.
Degradation of the Polymer
The degradation characteristics of PGS were examined both in vitro and in vivo. Slabs of dry polymer (5×5×2 mm) were weighed and transferred to 15 ml centrifuge tubes (Falcon) filled with PBS (pH: 7.4, Gibco, Carlsbad, Calif.) After 60 days, the samples were removed and washed with deionized water. The surface water was removed by Kimwipe, and the samples were weighed after drying at 40° C. in an oven for 7 days. The degree of degradation was determined by dry weight change.
Agitation for 60 days in phosphate buffered saline solution (PBS) at 37° C. caused the polymer to degrade 17±6% as measured by change of dry sample weight. In contrast, subcutaneous implants in rats were totally absorbed in 60 days. In the in vivo experiment, enzymes, and perhaps macrophages as well, may have caused differences in degradation rate. In vivo degradation thinned the polymer implants, with the explants maintaining their square shape and relatively sharp edges up to at least 35 days. Preliminary data indicate that mechanical strength probably decreases linearly with mass loss, e.g., ˜60% strength with ˜70% mass. Mechanical strength was measured on a nano-indenter that tests mechanical properties of minute samples. Both results suggest the polymer predominantly degrades through surface erosion. In contract, if the polymer exhibited bulk degradation, the mechanical strength would decrease well in advance of mass loss. The preservation of integrity during the degradation process can be important for certain types of tissue engineered implants, drug delivery devices, and in vivo sensors.
The in vivo degradation rates of PGS and PLGA were also compared. Flat sheets of PGS were cut into square blocks of 6×6×3 mm. Carboxylic acid ended PLGA (50:50, carboxyl ended, MW 15,000, Boehringer Ingelheim Inc., Germany) powder was pressed into round disks (diameter: 12.5 mm, thickness: 2 mm) by compression molding at 82° C. and 2000 psi for 6 min. The surface area/volume ratio was the same for PGS and PLGA samples. PGS samples were autoclaved (120° C., 20 min.), while PLGA samples were sterilized by ethylene oxide (4 h sterilization, 12 h ventilation) before implantation.
All samples were implanted subcutaneously in 15 seven-week-old female Sprague-Dawley rats. Each animal received 4 implants: 1 PGS and 1 PLGA each symmetrically on the upper and lower back. The animals were put under deep isofluorane/O2 general anesthesia before the surgical sites were shaved and sterilized with betadiene and 70% ethanol. The implants were inserted into a subcutaneous pocket created by blunt dissection. The wound was closed by wound clips, and the surgical sites were sterilized again with 70% ethanol. The animals were randomly divided into 5 groups. All the wound clips were removed 7 days postimplantation.
At day 7, 14, 21, 28, and 35, implants were explanted from one group of animals under deep isofluorane/O2 general anesthesia. Tissue samples (20×20 mm) surrounding the implants were removed with the implants intact. The implants were carefully removed and rinsed sequentially with phosphate buffered saline (PBS) solution and D.I. water.
Macroscopically, the PGS explants maintained its geometry throughout the time period tested (
SEM observation showed that the PGS explant surface maintained its integrity. Both pristine sterilized samples and cleaned and dried explants were mounted on aluminum stubs, and their surface morphologies were observed with a Philips FEI XL-30 FEG environmental scanning electron microscope under 2 Torr, 10 kV beam, 2.0 spot size, with gas phase secondary electron detector. Contoured features developed on the surface after autoclaving. Such features remained throughout the course of the experiment, however, no crack formation was observed (
The degree of swelling of degradable polymers in vivo is a key parameter for proper implant materials. Excessive swelling is usually undesirable for an implant, as it distorts the shape of the implant and softens the polymer (Yoon, J J, et al., Degradation behaviors of biodegradable macroporous scaffolds prepared by gas foaming of effervescent salts. J. Biomed. Mat. Res. 55:401-408, 2001; Kranz, H., et al., Physicomechanical properties of biodegradable poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) films in the dry and wet states. J. Pharm. Sci. 89:1558-1566, 2000). The swelling ratio was calculated from explant weight difference before and after drying: (Ww−Wd)/Wd, where Ww is the wet sample weight and Wd is the dry sample weight. The explants were cleaned and surface water removed with a Kimwipe before weighing. Each explant was thoroughly dried at 40° C. under vacuum (85 mTorr) for 48 h. Each explant was weighed again before any subsequent testing.
The water content of PGS implants rose linearly and reached 15% in 35 days, when the polymer degraded >70% (
The rate of mass loss is also an indicator of the degradation characteristics of a biodegradable polymer. PGS implants lost their weight steadily and linearly over the test period of 35 days, when they lost >70% of their mass (
One of the key functions of a degradable polymer in an implant is to provide mechanical support. Hence, it is important to know how the mechanical strength changes with degradation. The explants were tested according to ASTM standard D575-91 on Instron 5542 frame equipped with a 50 N or a 500 N load cell. Briefly, the explants were compressed at a fixed ramp speed of 2 mm/min. PGS explants were compressed to 50% strain, while PLGA explants were compressed to failure. Pristine samples and PGS explants have regular geometry and were measured with a digital caliper (Mitutoyo, 500-196 CD-6″CS). PLGA explants deform upon degradation, and their dimensions were measured to the best approximation. In this study, the mechanical strength is expressed by the compression modulus of the explants at about ⅓ of strain to failure (PLGA, 1%; PGS, 25%). The PGS implants lost mechanical strength gradually and slowly after implantation, about 8% each week. At day 35, when <30% of the PGS implant's mass was left, the modulus was >50% (
The differences in degradation characteristics between PGS and PLGA under identical conditions indicate they probably degrade by different mechanisms. Unlike PLGA, which degrades mostly by bulk degradation, in vivo degradation of PGS is dominated by surface erosion, as indicated by linear mass loss with time, preservation of implant geometry, better retention of mechanical strength, absence of surface cracks, and minimal water uptake. Upon degradation, PGS implants keep their integrity better than PLGA, and may prove useful in biomedical applications where such polymers are unsuccessful.
Composites and Mixtures
Bio-rubber may be combined with other polymers in blends and adducts to manipulate the degradation and mechanical properties of the material. Practically any biocompatible polymer may be combined with bio-rubber. In a preferred embodiment, the added polymer is biodegradable. Exemplary biodegradable polymers include natural polymers and their synthetic analogs, including polysaccharides, proteoglycans, glycosaminoglycans, collagen-GAG, collagen, fibrin, and other extracellular matrix components, such as elastin, fibronectin, vitronectin, and laminin. Hydrolytically degradable polymers known in the art include, for example, certain polyesters, polyanhydrides, polyorthoesters, polyphosphazenes, and polyphosphoesters. Biodegradable polymers known in the art, include, for example, certain polyhydroxyacids, polypropylfumerates, polycaprolactones, polyhydroxyalkanoates, poly(amide-enamines), polyamides, poly(amino acids), polyacetals, polyethers, biodegradable polycyanoacrylates, biodegradable polyurethanes and polysaccharides. For example, specific biodegradable polymers that may be used in the present invention include but are not limited to, polylysine, poly(lactic acid) (PLA), poly(glycolic acid) (PGA), copolymers and mixtures of PLA and PGA, e.g., poly(lactide-co-glycolide) (PLG), poly(caprolactone) (PCL), poly(lactide-co-caprolactone) (PLC), and poly(glycolide-co-caprolactone) (PGC). Those skilled in the art will recognize that this is an exemplary, not comprehensive, list of biodegradable polymers. The properties of these and other polymers and methods for preparing them are further described in the art. See, for example, U.S. Pat. Nos. 6,123,727; 5,804,178; 5,770,417; 5,736,372; 5,716,404 to Vacanti; 6,095,148; 5,837,752 to Shastri; 5,902,599 to Anseth; 5,696,175; 5,514,378; 5,512,600 to Mikos; 5,399,665 to Barrera; 5,019,379 to Domb; 5,010,167 to Ron; 4,806,621; 4,638,045 to Kohn; and 4,946,929 to d'Amore; see also Wang et al., J. Am. Chem. Soc. 123:9480, 2001; Lim et al., J. Am. Chem. Soc. 123:2460, 2001; Langer, Acc. Chem. Res. 33:94, 2000; Langer, J. Control Release 62:7, 1999; and Uhrich et al., Chem. Rev. 99:3181, 1999.
Bio-rubber may also be combined with non-biodegradable polymers. For example, polypyrrole, polyanilines, polythiophene, and derivatives thereof are useful electrically conductive polymers that can provide additional stimulation to seeded cells or neighboring tissue. Exemplary non-biodegradable polymers include, but are not limited to, polystyrene, polyesters, non-biodegradable polyurethanes, polyureas, poly(ethylene vinyl acetate), polypropylene, polymethacrylate, polyethylene, polycarbonates, and poly(ethylene oxide).
Alternatively or in addition, fibers and particles may be combined with the bio-rubber to modify its mechanical properties. For example, fibers, e.g., of collagen or PLGA, may be embedded in the bio-rubber to stiffen it. Particles of Bioglass™ or calcium phosphate ceramics may also be combined with the polymer.
Modification of Polymer Properties
The hydroxyl groups on bio-rubber provide sites to which molecules may be attached to modify the bulk or surface properties of the material (Jayachandran, K. N., et al., Synthesis of Dense Brush Polymers with Cleavable Grafts. Eur. Polym. J. 36: 743-749, 2000; Laschewsky, A., et al, Tailoring of Stimuli-responsive Water Soluble Acrylamide and Methacrylamide Polymers. Macromol. Chem. Phys. 202: 276-286, 2001). For example, tert-butyl, benzyl, or other hydrophobic groups may be added to the material to reduce the degradation rate. Polar organic groups such as methoxy also facilitate adjustment of both the degradation rate and hydrophilicity. In contrast, addition of hydrophilic groups, for example, sugars, at these sites would increase the degradation rate. Acids may also be added to the polymer to modify the properties of the material. For example, molecules with carboxylic or phosphoric acid groups or acidic sugars may be added. Charged groups such as sulfates and amines may also be attached to the polymer. Groups that are added to the polymer may be added via linkage to the hydroxyl group (substituting for hydrogen), linked directly to the polymer backbone by substituting for the hydroxyl group, or incorporated into an organic group which is linked to the polymer. For example, a charged amino acid such as arginine or histidine may be attached to the polymer to modify the degradation rate.
Attachment of such non-protein organic or inorganic groups to the polymer modifies the hydrophilicity and the degradation rate and mechanism of the polymer. Protecting group chemistry may also be used to modify the hydrophilicity of the material. One skilled in the art will recognize that a wide variety of non-protein organic and inorganic groups may be added to or substituted for the hydroxyl groups in the polymer to modify its properties. Exemplary functional groups are also described in March, Advanced Organic Chemistry. Fifth edition, John Wiley & Sons, Inc., New York, 1995, the entire contents of which are incorporated by reference herein.
To further control or regulate polymer interaction with cells, biomolecules, small molecules, or bioactive agents may be coupled to the hydroxyl groups or integrated into the polymer backbone (Barrera, D., et al., Synthesis and RGD Peptide Modification of a New Biodegradable Copolymer: Poly(lactic acid-co-lysine). J. Am. Chem. Soc. 115: 11010-11, 1993; West, J. L., et al., Polymeric Biomaterials with Degradation Sites for Proteases Involved in Cell Migration. Macromolecules 32: 241-244, 1999; Mann, B. K., Smooth Muscle Cell Growth in Photopolymerized Hydrogels with Cell Adhesive and Proteolytically Degradable Domains: Synthetic ECM Analogs for Tissue Engineering. Biomaterials 22, 3045-3051; 2001). Alternatively, biomolecules, small molecules, or bioactive agents may be encapsulated within the bio-rubber and perhaps linked to it using non-covalent interactions. Attachment of the moiety to the bio-rubber results in a slower release rate because it is released from the material as it degrades. In contrast, if the moiety is encapsulated within the bio-rubber, it may diffuse out of the material before the polymer degrades.
For example, biomolecules such as growth factors may be exploited to recruit cells to a wound site or promote specific metabolic or proliferative behavior in cells that are at the site or seeded within the matrix. Exemplary growth factors include, without limitation, TGF-β, acidic fibroblast growth factor, basic fibroblast growth factor, epidermal growth factor, IGF-I and II, vascular endothelial-derived growth factor, bone morphogenetic proteins, platelet-derived growth factor, heparin-binding growth factor, hematopoetic growth factor, and peptide growth factor. Integrins and cell adhesion sequences (e.g., the RGD sequence) may be attached to the bio-rubber to facilitate cell adhesion. Integrins are part of a large family of cell adhesion receptors that are involved in cell-extracellular matrix and cell-cell interactions. The RGD sequence, present in proteins such as fibronectin, has been shown to be active in promoting cell adhesion and proliferation (Massia, et al., J. Cell. Biol. 114:1089, 1991). Extracellular matrix components, e.g., collagen, fibronectin, laminin, elastin, etc., may be combined with bio-rubber to manipulate cell recruitment, migration, and metabolism and the degradation and mechanical properties of the material. Proteoglycans and glycosaminoglycans may also be covalently or non-covalently attached to bio-rubber.
Tissue Engineering Applications
The elasticity of bio-rubber recommends it for use in regenerating a variety of tissues. The material may be used to tissue engineer, for example, epithelial, connective, nerve, muscle, organ, and other tissues. Exemplary tissues that can benefit from the materials of the invention include artery, ligament, skin, tendon, kidney, nerve, liver, pancreas, bladder, and other tissues. Bio-rubber may also be used as the template for mineralization and formation of bone. Bio-rubber is especially recommended for regenerating tissues that are subject to repeated tensile, hydrostatic, or other stresses, such as lung, blood vessels, heart valve, bladder, cartilage and muscle.
Tissues experience mechanical forces and deformation in daily use, and tissue remodeling is often influenced by mechanical forces. For example, heart and other muscle will increase in density and size when they are frequently used and will atrophy under disuse. Mechanical force stimulates the cells that produce extracellular matrix elements to produce growth factors that promote either the production or degradation of ECM. Use of a material like bio-rubber that mimics a normal physiological response to mechanical forces will facilitate the regeneration of normal tissue, as mechanical stimulation can be applied early in the culturing of tissue engineered constructs.
For example, bio-rubber may be used to tissue engineer or regenerate a portion of a patient's bladder. In one embodiment, smooth muscle cells and urothelial cells are seeded onto bio-rubber. The cells may be allowed to proliferate before the implant is placed into a patient. To replace or regenerate cartilage, chondrocytes are seeded onto bio-rubber, which can withstand the cyclic shear and compressive forces cartilage is subjected to as joints bend.
Bio-rubber may also be used to produce prosthetic heart valves. Heart valves are very flexible and are subjected to cyclic deformation as the heart beats. The body repairs tears in heart valve through normal physiologic mechanisms and thus can regenerate heart valves made of biodegradable materials. A bio-rubber heart valve seeded with smooth muscle cells and endothelial cells will be remodeled in the body to produce a new, non-synthetic heart valve. In some embodiments, it may be desirable to add fibroblasts as well. In a preferred embodiment, the regeneration occurs over a period of 3 months. The degradation rate of the polymer is easily controlled by modifying the cross-link density and/or by modifying the hydroxyl groups with hydrophobic groups.
The shape of the bio-rubber may also be manipulated for specific tissue engineering applications. Exemplary shapes include particles, tubes, spheres, strands, coiled strands, films, sheets, fibers, meshes, and others. In one exemplary embodiment, microfabrication may be used to form capillary networks from bio-rubber. A silicon wafer is processed using standard microfabrication techniques to produce a capillary network having a desired pattern. The network is coated with a sacrificial layer, for example, sucrose. The prepolymer is cast over the sacrificial layer and cured according to the method described above. Water is used to dissolve the sacrificial layer and release the polymerized bio-rubber, which will have a relief pattern of the capillary networks that had been formed in the silicon wafer. In one embodiment, the channels in the bio-rubber are 7 μm across and 5 μm deep. One skilled in the art will realize, that while the size limit for the channels is dictated by the resolution of the microfabrication technique, biological applications may benefit from channel sizes on the order of 5 to 10's or 100's of microns or larger. The capillary networks may be closed by covering them with a flat sheet of bio-rubber and curing it. For example, a layer of uncrosslinked polymer may be used as a glue between the patterned layer and the flat layer. Polymerizing the "glue" will knit the two pieces together. Alternatively, the adhesive described below may be used to adhere the two pieces to one another. Further curing of the assembly will increase the cross-link density of the glue and form covalent bonds between the glue and the flat and patterned bio-rubber layers. In an alternative embodiment, an uncrosslinked flat bio-rubber film may be cured over a patterned film to cover the channels.
These shapes may be exploited to engineer a wider variety of tissues. For example, the polymer may be fabricated into a tube to facilitate nerve regeneration. The damaged nerve is fed into the end of the tube, which guides the migration of axons across the wound site. Alternatively, bio-rubber may be used to fabricate the tissue structures of liver. For example, it may be formed into a network of tubes that mimic a blood vessel and capillary network which may be connected to a nutrient supply to carry nutrients to the developing tissue. Cells may be recruited to the network of tubes in vivo, or it may be seeded with blood vessel cells. Around this network of tubes, bio-rubber may be formed into networks imitating the arrangements of extracellular matrix in liver tissue and seeded with hepatocytes. Similarly, the bio-rubber may be fabricated into a fibrous network, seeded with islet cells, and used to tissue engineer pancreas. The bio-rubber may also be seeded with a variety of other cells, for example, tenocytes, fibroblasts, ligament cells, endothelial cells, epithelial cells, muscle cells, nerve cells, kidney cells, bladder cells, intestinal cells, chondrocytes, bone-forming cells, stem cells such as human embryonic stem cells or mesenchymal stem cells, and others.
Medical Applications
Other medical applications may also benefit from the elasticity of the polymer of the invention. For example, after abdominal surgery, the intestines and other abdominal organs tend to adhere to one another and to the abdominal wall. It is thought that this adhesion results from post-surgical inflammation, however, anti-inflammatory drugs delivered directly to the abdominal region dissipate quickly. Bio-rubber may be used to deliver anti-inflammatory drugs to the abdominal region. Because bio-rubber is soft and flexible, it may be implanted between the abdominal wall and internal organs, for example, by attaching it to the abdominal wall, without cutting internal organs, which would lead to infection. The anti-inflammatory drug can be released from the bio-rubber over a period of months. While previous researchers have attempted to use hydrogels, hyaluronic acid-based membranes, and other materials to solve these problems, such materials tend to degrade quickly in the body; a longer resident period is necessary to prevent adhesion.
In another embodiment, bio-rubber may be used to coat a metallic stent. Because bio-rubber is flexible, it will expand with the stent without ripping, while the stiffness of the metal stent will prevent the bio-rubber from elastically assuming its previous shape. The bio-rubber may release heparin or other anti-coagulants or anti-inflammatory agents to prevent the formation of clots or scar tissue, which could close off the blood vessel or throw off a thrombus that could cause circulatory problems, including stroke, elsewhere in the body. Alternatively or in addition, angiogenic agents may be used to promote the remodeling of the blood vessel surrounding the stent. Indeed, any biomolecule, small molecule, or bioactive agent may be combined with the polymer. Such molecules may be covalently or non-covalently linked with the polymer.
Bio-rubber may also be used to prepare "long term" medical devices. Unlike typical permanent medical devices, bio-rubber will degrade over time. For example, the material may be fabricated into a biodegradable cardiac stent. Preferably, bio-rubber is combined with a harder polymer that plastically forms for the production of stents. Exemplary polymers include any of the polymers listed above, preferably biodegradable polymers. The bio-rubber acts as a plasticizer that enables the stent to expand into the desired shape after implantation. The stent increases the diameter of the blood vessel to allow easier circulation, but, because the stent is biodegradable, surrounding blood vessels increase in diameter without thrombosis or covering the stent with scar tissue, which would reclose the blood vessel. The time the stent should remain in place and retain its shape before degradation will vary from patient to patient and depend partially on the amount of blockage and the age of the patient (e.g., older patients require more time to heal). One skilled in the art will easily be able to adjust the molecular weight and cross-link density of the polymers in the stent to adjust the degradation rate. As for the coated stent, the degradable stent may release biomolecules, small molecules, bioactive agents, or some combination of these in situ.
The glycerol-diacid co-polymer may also be used as surgical glue. A biocompatible, biodegradable surgical glue may be used to stop bleeding during surgery but does not need to be removed before the surgeon sutures the wound closed and will degrade over time. Current surgical glues often use fibrin derived from bovine tissue, and a synthetic surgical glue reduces the risk of Creuzfeld-Jakob syndrome ("mad cow disease"). To produce the glue, the polymer should be held under vacuum for only 24 hours instead of 48, thus reducing the cross-link density, increasing the number of hydroxyl groups, and rendering the product exceedingly sticky. For example, after 24 hours under vacuum, the polymer will stick to supposedly non-stick materials such as polytetrafluoroethylene (PTFE). The stickiness may result from hydrogen bonding of the polymer with the adjacent material. While bio-rubber for tissue engineering applications typically has a cross-link density less than 10%, a glycerol-diacid co-polymer for use as a surgical glue has a cross-link density less than 1%, preferably less than 0.5%, and more preferably less than 0.05%.
Bio-rubber may also be used to support in vivo sensors and catheters. The polymer is constructed into a chamber for an optical fiber-based sensor or a coating for a catheter that is inserted into the area of interest. In a sensor, the chamber contains a specific chromophore-bonded receptor for the molecule of interest. When an analyte attaches to the receptor, the chromophore will either emit or absorb light at an specific wavelength. The absorption or emission may be detected by an apparatus connected to the optical fiber. The sensor may be used for short term, continuous monitoring, for example, for ten to fifteen days. Likewise, a catheter may be used to periodically deliver drugs or other small molecules or bioactive agents to a specific site or intravenously. Use of bio-rubber reduces the formation of scar tissue which would ordinarily form around a shunt or other implant that is used for more than two weeks. The degradation rate of the bio-rubber should be optimized so that there is not significant degradation of the material while it is in place in the patient.
Drug Release Applications
Bio-rubber may also be used for drug release applications, especially in applications where the matrix retaining the drug needs to be flexible. Because bio-rubber is elastic, it will move with the patient as he/she walks, runs, sits, etc. Because bio-rubber maintains its mechanical integrity as it degrades, the device is unlikely to fail catastrophically toward the end of its lifetime, reducing the risk of a bolus release of the desired agent. Biomolecules, small molecules, and bioactive agents may all be combined with bio-rubber using covalent or non-covalent interactions. Exemplary non-covalent interactions include hydrogen bonds, electrostatic interactions, hydrophobic interactions, and van der Waals interactions.
Bio-rubber may also be used for other wounds that are hard to close or that fail to heal properly through normal physiologic mechanisms. For example, diabetics often get skin injuries ("diabetic ulcers"), especially in the lower extremities, that take a long time to heal or fail to heal properly due to poor circulation. The use of bio-rubber to deliver antibiotics or anti-inflammatory agents to these wounds will aid healing and provide a cover for the wound.
Non-medical Applications
Bio-rubber may also be used for non-medical applications. For example, diapers are formed from a tough elastomer and liquid-permeable topsheet that encase an absorbent material. Currently, polypropylene is used for the elastomeric "casing". Polypropylene is not degradable and requires ten or more years to break down in a landfill. In contrast, bio-rubber is stable in a dry environment but will degrade in a landfill within two to four weeks after becoming wet. Similar products that can exploit the biodegradability of bio-rubber include incontinence protectors, sanitary napkins, panty liners, and wound dressings. Likewise, plastic bags, e.g., trash bags, may be made partially or entirety of the polymer of the invention. Where bio-rubber is used alone, it may be desirable to increase the cross-link density or modify the hydroxyl groups to increase the degradation time and prevent significant degradation before the bag reaches the landfill.
Bio-rubber may be exploited to protect not only natural resources but the animals that depend on those natural resources. For example, it is very popular to release helium filled balloons at various public events. The balloons eventually pop and drift back down to earth, where animals may choke while attempting to eat them. In contrast, balloons made out of bio-rubber would degrade upon exposure to the elements. Such balloons could eventually be digested by animals that eat them and would not present a continuing choking risk to animals once they degraded. In another embodiment, bio-rubber may be used to fabricate fishing lures or flies. When a fisherman loses a lure, the lure will simply sink to the bottom of the stream or lake and eventually degrade.
In another non-medical application, uncrosslinked glycerol-diacid co-polymers may be used as a base for chewing gum. For example, uncrosslinked material may be combined with a colorant, flavor enhancer, or other additive to produce a gum. The appropriate microstructure to produce a pleasant mouthfeel during chewing may be easily determined by polymerizing the polymer to different molecular weights and cross-link densities and chewing the resulting material for a few minutes.
The gum may also be adapted to deliver nutrients (e.g., vitamins) or drugs to the chewer. Nutrients may include FDA-recommended nutrients such as vitamins and minerals, amino acids, or various nutritional supplements available at health food stores. Such additives may simply be mixed with the glycerol-diacid co-polymer to produce a gum. Alternatively, they may be covalently attached to the polymer, preferably through hydrolyzable bonds or bonds that are lysed by the enzymes found in the mouth. As the gum is chewed, the nutrient or drug is released and swallowed. If the gum is swallowed, it will be completely metabolized in the digestive system.
Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.
Patent Citations
Non-Patent Citations
Referenced by
Legal Events
Original Image


text:
Perfect Storm of Turbulent Gases
June 20, 2003
Resembling the fury of a raging sea, this image actually shows a bubbly ocean of glowing hydrogen gas and small amounts of other elements such as oxygen and sulfur. The photograph, taken by NASA's Hubble Space Telescope, captures a small region within M17, a hotbed of star formation. M17, also known as the Omega or Swan Nebula, is located about 5,500 light-years away in the constellation Sagittarius.
Topics: Environment, Space, Sagittarius constellation, Astronomy, Technology Internet, Omega Nebula, Astrophysics, Nebula, Hubble Space Telescope


text:
Dollar (2006)
|Artist: Jamey Johnson
Song Listing
Album Notes and Credits
Notes & Personnel Info
|Personnel: Jamey Johnson (vocals); George Jones (vocals); Wayd Battle, Pat Buchanan (electric guitar); Steve Hinson (steel guitar); David Talbot (banjo); Rob Hajacos (fiddle); Kirk "Jelly Roll" Johnson (harmonica); Jim "Moose" Brown (piano, organ, Wurlitzer organ); Randy McCormick (piano, Wurlitzer organ, keyboards); Gary Prim (piano); Kevin Grantt (bass guitar); Cindy Walker, D. Bergen White, Trenna Barnes, Duane Hamilton, Jon Mark Ivey, Lisa Cochran, Lisa Silver, Marabeth Jordon, Melodie Crittenden, Liana Manis, Melonie Cannon, Louis Dean Nunley, Wyatt Beard (background vocals); John Willis (acoustic guitar, banjo); J.T. Corenflos (electric guitar); Dan Dugmore (steel guitar, dobro); Chad Cromwell (drums); Tom Roady (percussion).
|Audio Mixer: T.W. Cargile.
|Recording information: County Q Productions; Emerald Sound Studios; Loveshack Studios; Masterfonics Studios; Sounds Stage Studios; The Sound Kitchen, Nashville, TN; WEstwood Sound Studios.
|Photographer: Russ Harrington.
|Despite a handsome mug and a beefy build, Nashville newcomer Jamey Johnson proves that he's more than just a "hat act" on his 2006 debut, THE DOLLAR. Johnson's neo-traditionalist bent fares well on these 11 tracks, most of which he wrote himself, or co-wrote. While the lyrical themes--work, love, faith, and partying--will not surprise listeners of contemporary country, the freshness of Johnson's songwriting and the appeal of his ragged baritone may. THE DOLLAR balances between emotionally charged ballads and honky-tonk rockers, and Johnson delivers the goods in both styles, making this a solid first outing worth hearing.
Producer: Buddy Cannon; Buddy Cannon
Engineer: Chris Rowe; Steve Marcantonio; T.W. Cargile; Tony Castle; Billy Sherrill; Butch Carr
Compilation Appearances
|Now That's What I Call Country Vol 2
|Take The High Road
|We Walk the Line-Celebration of Johnny Cash
|At The Ryman
|At The Ryman
Associated Artists and Works
|Jennings, Shooter
Technical Info
|Release Date : 01/31/2006
|Original Release Date : 2006
|Catalog ID : 72690
|Label : Sony Music Distribution (USA)
|Number of Discs : 1
|Studio/Live : Studio
|Mono/Stereo : Stereo
|SPAR Code : n/a
Customer Reviews of Dollar
Promising newcomer adds grit to Nashville debut2/5/2006
Johnson's baritone shows a touch of fellow Alabaman Vern Gosdin, but with a rougher finish that gives his voice an appealing edge. His songs (he wrote or co-wrote seven of these eleven titles) range from homespun ("The Dollar") to rowdy ("Rebelicious") to soulfully spiritual ("Lead Me Home"). The upbeat numbers often sound derivative of Big and Rich's sound, making "Ray Ray's Juke Joint" more rock than swamp and "Redneck Side of Me" more sized for an arena than a bluesy roadhouse. ¶ Where Johnson's personality shines through is on the ballads and mid-tempo numbers. "Flying Silver Eagle," with guitar sounds mined from Haggard's greatest hits of the '70s, is a stellar song of a romantic dead-end turned into personal freedom, and the album's title hit is a clever, sweet song of a young son's love of time spent with his father. "Lead Me Home" is the sort of funereal song that Patty Loveless has successfully used to close many of her albums; Johnson's original song of life after death is moving and powerful. ¶ There's enough radio-friendly fare here to clearly mark this as a major-label Nashville project. But just the same, Johnson has his own artistic voice, both in words and vocals, and producer Buddy Cannon's done a nice job of framing it both for radio and for posterity. Modern country fans will like the more contemporary tracks, while others will find a surprising helping of earthier sounds sprinkled throughout. 3-1/2 stars, if allowed fractional ratings. [©2006 redtunictroll at hotmail dot com]


text:
Eric Sanderson:
Eric Sanderson描述紐約市的前身
在哈德遜發現紐約港400年後,Eric Sanderson 向我們講述了他是如何製作了一張極其精確的3D地圖:曼哈頓在成為城市之前的生態圖,裡面有山丘,有河流還有野生動植物,當時的時代廣場還是一片荒蕪濕地。
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text:
AJGA Annapolis Junior
Old South Country Club
Lothian, Md. • July 7 - 10, 2014
American Junior Golf Association • Contact: Chris Richards • (678) 425-1788 • email@example.com
Quick Facts
- 96 Boys and Girls, ages 12-18
- Format: 54 holes, stroke play
- Four AJGA champions
- This will be the second consecutive year Old South Country Club will host the AJGA
- Seven players have made a verbal commitment to play college golf
- Six players have signed a National Letter of Intent to play college golf
- 15 states will be represented
Tournament Storylines
|College bound: 33 players have committed to play golf at the college of their choice.
|Local flavor: 28 players from Maryland will compete.
|Three top finishers return
|Three of the top-five finishers in the Boys Division will return after a successful 2013 showing at Old South Country Club. Charlie Kennerly (T3) of Jupiter, Fla., Charles Musto (T3) of Sterling, Va. and Michael Graboyes (5) of Watchung, N.J. will all be making their second appearance at the AJGA Annapolis Junior.
|Calbi siblings make a second appearance
|Julia and Thomas Calbi will compete in the AJGA Annapolis Junior for the second straight year. Julia finished ninth in 2013 while Thomas finished T26. This will mark the sixth time the siblings have competed together in AJGA events and first of 2014.
Schedule of Events
|Monday, July 7
|2 p.m. shotgun
|Practice Round
|Tuesday, July 8
|7 a.m. – 12:10 p.m.
|First Round off No. 1 tee
|Wednesday, July 9
|7 a.m. – 12:10 p.m.
|Second Round off No. 1 tee
|Thursday, July 10
|7 a.m. – 12:10 p.m.
|Final Round off No. 1 tee
|5 p.m.
|Awards Ceremony
Top Players to Watch
|Michael Graboyes, Watchung, N.J. (2014)
|Graboyes comes in as the top-ranked boy in the field at No. 125 in the Polo Golf Rankings. The Cornell commit has notched three top-five finishes in his career, including one at the 2013 AJGA Annapolis Junior.
|Bennett Buch, West Friendship, Md. (2016)
|At No. 156, Buch is the highest-ranked player from the host state in the field. The Elon verbal commitment tied for eighth at the 2013 AJGA Annapolis Junior and recently won the 2014 AJGA Junior at Cattail Creek.
|Jiayu Kong, (China) Arcadia, Calif. (2016)
|Kong enters the tournament as the lone recipient of Rolex Junior All-America honors after being named an honorable mention in 2013. The champion of the 2013 Coca-Cola Junior Championship at Sugarloaf is also the highest-ranked player in the field at No. 64 in the Polo Golf Rankings.
|Julie Luo, Centreville, Va. (2015)
|The only player in the field with multiple AJGA victories, Luo enters the event at No. 99 in the Polo Golf Rankings. The Centreville, Va. native has amassed eight top-six finishes since 2009.
|Nikolette Schroeder, Avon Lake, Ohio (2015)
|The Ohio State verbal commit will compete in her second AJGA event of the 2014 season after placing fourth at the AJGA Junior at Sugar Valley. Schroeder has compiled seven top-10 finishes in national competition, including two runner-up finishes, on her way to a No. 127 ranking.
2013 Results
AJGA Annapolis Junior
Old South Country Club (July 8 - 11, 2013)
|Boys Division
|Jake Leavitt
|Woodstock, Md.
|Connor Messick
|Oak Hill, Va.
|Charles Musto
|Sterling, Va.
|Charlie Kennerly
|Jupiter, Fla.
|Michael Graboyes
|Watchung, N.J.
|Girls Division
|Hana Ku
|Basking Ridge, N.J.
|Anina Ku
|Basking Ridge, N.J.
|Young Shin Kim
|Austin, Texas
|Tatiana Wijaya
|(Indonesia) Perth, Australia
|Shannon Brooks
|Vienna, Va.
Media Accommodations
The AJGA Annapolis Junior will have AJGA communications representatives on hand to assist media throughout the week. Prior to the tournament the AJGA will provide information about the event and its participants, as well as assist with player interviews.
After each round, media officials on-site will write a recap with the day's results. These will be emailed to all media outlets. Interviews with AJGA Tournament Directors, Tournament Chairmen and juniors may be conducted before or after tournament rounds.
For more information about the AJGA and tournaments, please refer to ajga.org. Tournament websites are accessible from the homepage and include recaps, list of participants, tee times, live scoring, course and sponsorship information.
About the AJGA
The American Junior Golf Association is a 501(c)(3) nonprofit organization dedicated to the overall growth and development of young men and women who aspire to earn college golf scholarships through competitive junior golf. The AJGA provides valuable exposure for college golf scholarships, and has an annual junior membership (boys and girls, ages 12-18) of more than 6,300 members from 48 states and more than 50 foreign countries. Through initiatives like the Achieving Competitive Excellence (ACE) Grant, a financial assistance program, and Leadership Links, a service-oriented platform that teaches juniors charitable-giving skills, the AJGA fosters the growth of golf's next generation.
Titleist, the AJGA's National Sponsor, has been the catalyst and driving force behind the Association's success since 1989. Rolex, which is in its fourth decade of AJGA support, became the inaugural AJGA Premier Partner in 2004. In 2007, after 12 years of support, Ralph Lauren became the AJGA's second Premier Partner.
AJGA alumni have risen to the top of amateur, collegiate and professional golf. Former AJGA juniors have compiled more than 600 victories on the PGA and LPGA Tours. AJGA alumni include Jordan Spieth, Brandt Snedeker, Bubba Watson, Webb Simpson, Hunter Mahan, Phil Mickelson, Tiger Woods, Stacy Lewis, Vicky Hurst, Inbee Park, Paula Creamer, Cristie Kerr, Brittany Lincicome and Morgan Pressel.
Tournament field
|Boys Division
|John Abbott
|Hummelstown, Pa.
|Eric Austin
|Northford, Conn.
|Brendan Bacskai
|Berwyn, Pa.
|Max Bell
|Chambersburg, Pa.
|Kyle Berkshire
|Crofton, Md.
|Brandon Berry
|Great Falls, Va.
|Mike Blasey
|Potomac, Md.
|Bennett Buch
|West Friendship, Md.
|Alex Butler
|East Norriton, Pa.
|Thomas Calbi
|South Barrington, Ill.
|Christian Cavaliere
|Katonah, N.Y.
|Colton Christensen
|Potomac, Md.
|Nathan Chuwait
|Herndon, Va.
|Michael Conforti
|Palm Beach Gardens, Fla.
|Kyle Cunningham
|Sayville, N.Y.
|Ryan Davis
|Berkeley Heights, N.J.
|Gunnar Doyle
|Pittsford, N.Y.
|Erik Dulik
|Great Falls, Va.
|Walter Egloff
|Chevy Chase, Md.
|Michael Graboyes
|Watchung, N.J.
|Colton Grow
|Henrico, Va.
|Will Halamandaris
|Crownsville, Md.
|Eric Hall
|Harwood, Md.
|Patrick Hallisey
|Wethersfield, Conn.
|Cole Hand
|Wheeling, W.Va.
|David Hicks
|Cape May Court House, N.J.
|Jonathan Hsu
|Atlanta, Ga.
|Michael Jones
|Potomac, Md.
|Sam Jung
|(South Korea) Centreville, Va.
|Evan Katz
|Washington, D.C.
|Charlie Kennerly
|Jupiter, Fla.
|Manuel Kent
|(Paraguay) Weston, Fla.
|Peter Knade
|Easton, Md.
|Brett Krekorian
|Andover, Mass.
|Davis Lamb
|Potomac, Md.
|Joey Lawrence
|Augusta, Ga.
|Liam McAnally
|Downingtown, Pa.
|Scott McKean
|Chester Springs, Pa.
|Tyler Mealey
|Edgewater, Md.
|Nicholas Mejia
|Woodstock, Md.
|Blake Micholas
|Potomac, Md.
|Jake Miles
|Spotsylvania, Va.
|Benjamin Morris
|Reisterstown, Md.
|Charles Musto
|Sterling, Va.
|Chris Navarro
|Davidsonville, Md.
|Ethan Ng
|New York, N.Y.
|Jake Niedosik
|Lansdale, Pa.
|Ty Olinger
|Blacksburg, Va.
|Tyler Olmsted
|Boyds, Md.
|Edward Owen
|Baltimore, Md.
|John Pak
|Scotch Plains, N.J.
|Rij Patel
|Hunt Valley, Md.
|Boyd Peete
|Richmond, Va.
|McCullough Pickens
|St. Simons Island, Ga.
|David Rabil
|Fairfax Station, Va.
|Jake Reilly
|Hershey, Pa.
|Peter Richards
|Westport, Conn.
|Josh Rinehart
|York, Pa.
|Ryan Rucinski
|Wilmington, Del.
|Michael Savitt
|Greenwich, Conn.
|Luke Schaap
|Potomac, Md.
|Taso Scilaris
|Bethesda, Md.
|Steven Segrist
|Glenwood, Md.
|Jake Sollon
|Venetia, Pa.
|Dylan Stein
|Flemington, N.J.
|Jordan Weitz
|Rockville, Md.
|Edric Wung
|McLean, Va.
|Brandon Yoon
|Brambleton, Va.
|Justin Zheng
|Belle Mead, N.J.
|Victor Zhou
|New Britain, Conn.
|Girls Division
|Sasha Banks
|Rancho Santa Fe, Calif.
|Hannah Berman
|Ponte Vedra Beach, Fla.
|Kaitlyn Bingham
|Phoenix, Md.
|Hana Bradshaw
|San Diego, Calif.
|Julia Calbi
|South Barrington, Ill.
|Sophie DiPetrillo
|Dover, Mass.
|Ashley Kim
|Redondo Beach, Calif.
|Eunbbie Kim
|Potomac, Md.
|Jiayu Kong
|(China) Arcadia, Calif.
|Julianne Lee
|York, Pa.
|Abby Lim
|Tenafly, N.J.
|Julie Luo
|Centreville, Va.
|Sydney Mills
|Severna Park, Md.
|Naomi Mitchell
|Norfolk, Va.
|Sophia Morrill
|Hanover, Mass.
|Danielle Nicholson
|Geneva, Ohio
|Alexandra Sazhin
|(Russian Federation) Old Greenwich, Conn.
|Maggie Schoeller
|Jenkintown, Pa.
|Nikolette Schroeder
|Avon Lake, Ohio
|Charlotte Simpson
|Towson, Md.
|Elise Sumner
|North Tustin, Calif.
|Micaa Thomas
|Bowie, Md.
|Allison Wong
|Rockville, Md.


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Interesting. What color cream/polish did you use In caring for them? I find your pair darkened quite dramatically. Or maybe mine lightened over the course of 5 years...
post #1606 of 9406
5/16/12 at 3:23pm
- Posts: 4,827
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- Location: Silicon Valley
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By Nestor Cardozo
Open the Mac App Store to buy and download apps.
GeoCalc is a calculator for vectors (lines and planes), and tensors (strain and stress). Multiple calculators can be opened, edited and saved. Entries and results are presented in tables, as well as in a stereonet and a Mohr circle. In addition in 3D stress, the stereonet and Mohr circle can be colored by slip tendency. Entries can be read from text files. Results can be exported as text and plots. GeoCalc is a powerful tool to perform operations on thousands of vectors or tensors. It is also a great tool to learn the stereonet and the Mohr circle.
What's New in Version 5.3
- Further optimisations
- Remove one redundant operation in the Planes and Lines view
- updated documentation
- Free
- Category: Productivity
- Updated: Feb 26, 2015
- Version: 5.3
- Size: 3.7 MB
- Language: English
- Seller: Nestor Cardozo
- © Nestor Cardozo
Compatibility: OS X 10.8 or later, 64-bit processor


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Mitchell Guist and Brother: Swamp People Sneak Peekby Hilton Hater at . Comments
Dont we all wish we could be as happy as Mitchell! I will miss your stories...
My prayers are with the family and friends of the Guist family. The brothers added a closeness and a warm family value to the show. Mitchell will be greatly missed--especially by his brother. My heart goes out to this family--may he R.I.P. The show will be missing a big element of the show.
A very sad day for us all...he will be greatl y missed...my regrets to family!
we will all ways miss you buddy
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