151
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Williams DF, Askill IN, Smith R. Protein absorption and desorption phenomena on clean metal surfaces. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1985; 19:313-20. [PMID: 4077885 DOI: 10.1002/jbm.820190312] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The noncompetitive adsorption of the proteins albumin and fibrinogen onto 17 different metal surfaces has been studied in vitro using 125I-labeled proteins. Although many of the metals showed very similar adsorption characteristics to polymers, several of them adsorbed considerably greater amounts. Copper, gold, and silver were the most significant in this respect, all three being face-centered cubic, group 1B metals known to bind to many types of protein in vitro and in vivo. The desorption of the proteins was studied in an in vivo model in which preproteinized metals were implanted in rats. There was considerable variations in the amounts of the proteins removed from the various metal surfaces. Generally those metals onto which protein is most readily adsorbed tend to lose the protein quickly, whereas others, such as iron, with only moderate adsorbed amounts, may retain a large part of the adsorbed layer for a long time.
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152
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Miller ND, Williams DF. The in vivo and in vitro degradation of poly(glycolic acid) suture material as a function of applied strain. Biomaterials 1984; 5:365-8. [PMID: 6098316 DOI: 10.1016/0142-9612(84)90037-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The in vivo and in vitro stability of a degradable suture material, poly(glycolic acid) has been shown to be dependent on the magnitude of a pre-imposed strain. The degradation, monitored by changes in the tensile load at break, was considerably enhanced by pre-straining the material to one half of the normal extension at break, using a novel implantable device.
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Abstract
A cloth-sandwich construction of a carbon-carbon composite material has been implanted in the femora of a series of rats and the response of the bone to this material compared to the response to titanium. It is shown that the carbon provides for excellent hard tissue biocompatibility. When the composite has a surface texture associated with fibre run out there is a degree of bony attachment, the interfacial shear strength for the composite-bone system being significantly greater than that for the titanium-bone system during the period 4-40 weeks post implantation.
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155
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Chu CC, Williams DF. Effects of physical configuration and chemical structure of suture materials on bacterial adhesion. A possible link to wound infection. Am J Surg 1984; 147:197-204. [PMID: 6364858 DOI: 10.1016/0002-9610(84)90088-6] [Citation(s) in RCA: 126] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The purpose of this study was to examine the effects of physical configuration and the chemical nature of suture materials on the preferential adherence of bacteria. Ten suture materials of 2-0 (chromic catgut, Dexon, Vicryl, PDS, Mersilene, Tycron, Ethibond, Surgilon, Ethilon, and Prolene) were used. The bacterial strains tested were Staph. aureus and E. coli. The level of bacterial adherence was determined quantitatively by radiolabelled cells and qualitatively by scanning electron microscopy. It was found that the amount of adhered bacteria depended on the type of suture material, the type of bacteria, and the duration of contact. In the group of absorbable sutures, the new PDS sutures exhibited the smallest affinity toward the adherence of both E. coli and Staph. aureus. Dexon sutures had the highest affinity toward these two bacteria. With nonabsorbable sutures, the physical configuration of the sutures contributed more to their ability to attract bacteria than the surface finish. The bacterial adherence on suture materials was also time dependent. Scanning electron microscope morphologic observation also indicated that Staph. aureus adhered on the suture surface in clusters whereas E. coli tended to adhere individually.
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156
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McNamara A, Williams DF. Enzyme histochemistry of the tissue response to pure metal implants. ACTA ACUST UNITED AC 1984. [DOI: 10.1002/jbm.820180208] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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157
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Chu CC, Williams DF. The effect of gamma irradiation on the enzymatic degradation of polyglycolic acid absorbable sutures. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1983; 17:1029-40. [PMID: 6317694 DOI: 10.1002/jbm.820170612] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The purpose of the study was to examine the effect of gamma irradiation on the enzymatic as well as the in vivo degradation of polyglycolic acid sutures. The sutures of size 2-0 were irradiated at dosage levels of 0-20 mrad. The three enzymes chosen for this study were esterase, alpha-chymotrypsin, and trypsin. The irradiated sutures were both immersed in the enzyme solutions; their corresponding buffer controls, and implanted in inbred black-and-white hooded hister rats (Liverpool strain). The degradation of PGA sutures was determined mechanically. Among the three enzymes studied, esterase showed the highest enzymatic effect on the degradation of the unirradiated and irradiated PGA sutures. Trypsin's effect on PGA sutures was not observed until 20 mrad. The findings of trypsin demonstrated the hypothesis that synthetic high molecular weight polymers, which are initially resistant to enzymatic degradation, could become prone to enzymatic attack after altering their physical and chemical structures. Implanted PGA sutures maintained a similar or slightly higher mean tensile breaking strength in in vivo degradation compared to in vitro degradation (0.1M tris buffer of pH = 7.5); these degradation profiles suggest that PGA does not display similar behavior in in vivo and in vitro degradations. The magnitude of dissimilarity depends on the radiation dosage and on the duration of degradation, and is speculated to be attributable to the specific action of enzymes with respect to the configuration and chemical structure of the PGA sutures.
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158
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Williams DF, Gore LF, Clark GC. Quantitative microradiography of cortical bone in disuse osteoporosis following fracture fixation. Biomaterials 1983; 4:285-8. [PMID: 6640055 DOI: 10.1016/0142-9612(83)90029-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Stainless steel (elastic modulus 210 GN/m2) and carbon fibre reinforced epoxy resin (elastic modulus 65 GN/m2) plates have been attached to intact femora in cats and the development of disuse osteoporosis assessed by microdensitometric methods after 8 months. The bone adjacent to the stainless steel plate showed evidence of considerable demineralization, both uniformly throughout a section and especially at certain focal points. A noticeable, but much smaller amount of osteoporosis developed adjacent to the composite plate. Various methods of presenting quantitative micro-densitometric data are used.
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159
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Williams DF, Cunningham J, Lalor MJ, Groves D, Atkinson JT. Laser techniques for the evaluation of wear in Class II restorations. J Oral Rehabil 1983; 10:407-14. [PMID: 6579265 DOI: 10.1111/j.1365-2842.1983.tb00137.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A technique for the quantitative determination of the changes in surface topography of restorations during wear has been developed. This involves the optical contouring of the surface using a laser, and the generation of contour maps. Several different methods for interpreting these maps are discussed. A computer-aided method is the most consistently accurate and measures wear volume to an accuracy of 2--5%.
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160
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Causton BE, Braden M, McCabe JF, Brown D, Prosser HJ, Coombe EC, Waters NE, Cruickshanks-Boyd DW, Watts DC, Fletcher AM, Williams DF, Kuhn AT, Wilson AD, Lloyd CH, Wilson HJ. Dental materials: 1980 literature review. Part 2. J Dent 1983; 11:95-132. [PMID: 6136537 DOI: 10.1016/0300-5712(83)90212-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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161
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Glancey BM, Lofgren CS, Williams DF. Avermectin B1a: effects on the ovaries of red imported fire ant queens (Hymenoptera: Formicidae). JOURNAL OF MEDICAL ENTOMOLOGY 1982; 19:743-747. [PMID: 7154028 DOI: 10.1093/jmedent/19.6.743] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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162
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Lofgren CS, Williams DF. Avermectin B1a: highly potent inhibitor of reproduction by queens of the red imported fire ant (Hymenoptera: Formicidae). JOURNAL OF ECONOMIC ENTOMOLOGY 1982; 75:798-803. [PMID: 7175003 DOI: 10.1093/jee/75.5.798] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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163
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McNamara A, Williams DF. Scanning electron microscopy of the metal-tissue interface. II. Observations with lead, copper, nickel, aluminium, and cobalt. Biomaterials 1982; 3:165-76. [PMID: 7115861 DOI: 10.1016/0142-9612(82)90007-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The nature of the metal-tissue interface following the implantation of five pure metals, lead, copper, nickel, aluminium and cobalt, in rats has been observed by scanning electron microscopy. The general conclusion, derived from light microscopy that the tissue response to pure metals is characteristic of and specific to individual pure metals has been confirmed in this study. However, far more detailed observations of factors such as the extent of metallic corrosion, the distribution of red blood cells, platelets and other cells in the capsule and adherent to the metal surface, have been possible with SEM.
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164
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McNamara A, Williams DF. Scanning electron microscopy of the metal-tissue interface. I. Fixation methods and interpretation of results. Biomaterials 1982; 3:160-4. [PMID: 7115860 DOI: 10.1016/0142-9612(82)90006-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Scanning electron microscopy has been used to study the interface between implants of pure metals and the muscular tissue of rats. Several problems arise in the interpretation of the observations made, due to the potential for disruption to the tissue and the exacerbation of any corrosion that may have occurred in vivo during the fixation periods. Details are given of the control experiments performed in order to ascertain the nature of potential artefacts and of the techniques eventually determined to be optimal for these purposes.
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165
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Meachim G, Pedley RB, Williams DF. A study of sarcogenicity associated with Co-Cr-Mo particles implanted in animal muscle. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1982; 16:407-16. [PMID: 7107658 DOI: 10.1002/jbm.820160409] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A study has been made of the sarcogenicity of particles of cobalt-chromium-molybdenum alloy. The particles were implanted as a dry powder into a surgical incision into the dorsal paraspinal muscle of adult female rats and guinea pigs. Two preparations were used. In one, the particles had a size range of 100-250 micrometers. This preparation was implanted into 51 Wistar rats. In the other, the particles had a size range of 0.5-50 micrometers, 85% being in the range 0.5-5 micrometers. This preparation was implanted into 61 Wistar rats, 53 hooded rats, and 46 Dunkin Hartley guinea pigs. Sham operations were carried out on a control group of 50 Wistar rats. No malignant neoplasms developed at the test or control operation sites during the time periods for which the animals survived. This negative finding contrasts with that from a previous study by Health, Freeman and Swanson, who observed sarcomas in rats at sites of intramuscular injection of cobalt-chromium-molybdenum particles suspended in horse serum. Possible explanations for this difference in results are discussed.
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166
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Clark GC, Williams DF. The effects of proteins on metallic corrosion. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1982; 16:125-34. [PMID: 7061531 DOI: 10.1002/jbm.820160205] [Citation(s) in RCA: 114] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The corrosion of the pure metals aluminium, cobalt, copper, chromium, molybdenum, nickel, and titanium and of a cobalt-chromium molybdenum casting alloy has been studied in buffered saline with and without the presence of the proteins serum albumin and fibrinogen. The corrosion of aluminium and titanium was unaffected by the protein. The corrosion rates of chromium and nickel showed a slight increase, while cobalt and copper dissolved to a very much greater extent in the presence of protein. However, with molybdenum the corrosion was inhibited by protein.
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167
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Williams DF. Eye for eye, tooth for tooth; a materialistic overview of contemporary prostheses. J Med Eng Technol 1982; 6:12-8. [PMID: 7120348 DOI: 10.3109/03091908209032566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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168
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Brown D, Braden M, Causton BE, Combe EC, Cruickshanks-Boyd DW, Fletcher AM, Lloyd CH, McCabe JF, Miller M, Prosser HJ, Waters NE, Watts DC, Williams DF, Wilson AD, Wilson HJ. Dental materials: 1979 literature review. Part II. J Dent 1981; 9:271-98. [PMID: 7033315 DOI: 10.1016/0300-5712(81)90001-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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169
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Fünfschilling J, Zschokke‐Gränacher I, Williams DF. The determination of the site‐energy distribution of organic molecules dissolved in glassy matrices. J Chem Phys 1981. [DOI: 10.1063/1.442531] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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170
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Brown D, Braden M, Miller M, Causton BE, Prosser HJ, Combe EC, Waters NE, Cruickshanks-Boyd DW, Watts DC, Fletcher AM, Williams DF, Lloyd CH, Wilson AD, McCabe JF, Wilson HJ. Dental materials: 1979 literature review. Part I. J Dent 1981; 9:177-209. [PMID: 7024355 DOI: 10.1016/0300-5712(81)90056-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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171
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Altay C, Gravely ME, Joseph BR, Williams DF. alpha-thalassemia-2 and the variability of hematological values in children with sickle cell anemia. Pediatr Res 1981; 15:1093-6. [PMID: 7267182 DOI: 10.1203/00006450-198108000-00004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Seventy children homozygous for Hb S (SS) and their 111 heterozygous (AS) parents were evaluated through their erythrocytic indices, hemoglobin composition, and occasionally through in vitro Hb chain synthesis values. Three groups of SS patients and of AS parents were identified based on differences in degree of microcytosis (MCV) and (degree of hypochromia (MCH) values. The level of Hb S in the Hb S heterozygotes showed a trimodal distribution. Five SS patients had an alpha-thalassemia homozygosity (alpha(0) alpha/alpha(0) alpha; beta(s)/beta(s) which was characterized by a distinct microcytosis and hypochromia (MCV), less than or equal to 70 fl; MCH, less than or equal to 22 pp). Nine SS patients had an alpha-thalassemia heterozygosity (alpha(0)/alpha/alpha alpha; beta(s)/beta(s)) with an MCV value of 71 to 78 fl, and an MCH value of 21.3 to 26.5 pg. Four AS parents had an alpha-thalassemia-2 homozygosity with values of MCV less than or equal to 71 fl and MCH less than or equal to 23.5. The level of Hb S was less than 31%. Thirty-nine AS parents had an alpha-thalassemia-2 heterozygosity characterized by an MCV value of 72 to 79 fl, an MCH value of 23.6 to 26.5, and a level of Hb S ranging between 31.0 and 36.8%. The Hb A2 level in SS patients was significantly correlated with the RBC counts and the MCV and MCH (r = 0.38, -0.52, and -0.47, respectively). Significant correlations in AS parents were also noted between the MCV, MCH, RBC, and Hb S percentages (r = 0.62, 0.68, and -0.49, respectively). Although the data are limited, the simultaneous occurrence of an alpha-thal-2 homozygosity seems to decrease the level of Hb F in sickle cell anemia. The presence of an alpha-thal-2 heterozygosity or homozygosity together with an SS or AS condition resulted in identifiable hematologic phenotypes.
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172
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Williams DF. In search of perfect dental materials. Br Dent J 1981; 151:24-7. [PMID: 7018530 DOI: 10.1038/sj.bdj.4804623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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173
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174
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Williams DF, Patterson RS, LaBrecque GC, Weidhaas DE. Control of the stable fly, Stomoxys calcitrans (Diptera: Muscidae), on St. Croix, U.S. Virgin Islands, using integrated pest management measures. II. Mass rearing and sterilization. JOURNAL OF MEDICAL ENTOMOLOGY 1981; 18:197-202. [PMID: 7328606 DOI: 10.1093/jmedent/18.3.197] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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175
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Patterson RS, LaBrecque GC, Williams DF, Weidhaas DE. Control of the stable fly, Stomoxys calcitrans (Diptera: Muscidae), on St. Croix, U.S. Virgin Islands, using integrated pest management measures. III. Field techniques and population control. JOURNAL OF MEDICAL ENTOMOLOGY 1981; 18:203-210. [PMID: 7328607 DOI: 10.1093/jmedent/18.3.203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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176
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LaBrecque GC, Patterson RS, Williams DF, Weidhaas DE. Control of the stable fly, Stomoxys calcitrans (Diptera: Muscidae), on St. Croix, U.S. Virgin Islands, using integrated pest management measures. I. Feasibility of sterile male releases. JOURNAL OF MEDICAL ENTOMOLOGY 1981; 18:194-196. [PMID: 7328605 DOI: 10.1093/jmedent/18.3.194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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177
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Abstract
Discs of five high-purity metals, cobalt, nickel, copper, aluminium and lead have been implanted intramuscularly in rats and the response observed histologically for period up to 52 weeks. A reproducible but different response was observed with each metal. Whenever corrosion occurred, as with copper, nickel and some cobalt specimens, the implants became loose. In the absence of corrosion, the implants were firmly held within a more confined capsule. A minimal response was seen with lead, implying normally toxic metals do elicit an immune response whilst some, especially copper and nickel appear to render the host more susceptible to disease. The implants appear to have a profound effect on the immediate vasculature, are able to cause a prolonged polymorphonuclear response in the same way as bacteria, are associated with varying amounts of haemosiderin laden macrophages but not with giant cells. The animals appear to be able to deal with bacteria introduced at surgery without hindrance from the metal.
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178
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Brown D, Braden M, Causton BE, Combe EC, Cruickshanks-Boyd DW, Lloyd CH, Main C, McCabe JF, Miller M, Tranter TC, Waters NE, Watts DC, Williams DF, Wilson AD, Wilson HJ. Dental materials: 1978 literature review. Part II. J Dent 1980; 8:222-48. [PMID: 7002967 DOI: 10.1016/0300-5712(80)90075-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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179
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Dalal NS, Haley LV, Northcott DJ, Park JM, Reddoch AH, Ripmeester JA, Williams DF, Charlton JL. Influence of deuteration on the order–disorder phase transition of anthracene–tetracyanobenzene. J Chem Phys 1980. [DOI: 10.1063/1.440368] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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180
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Brown D, Braden M, Causton BE, Combe EC, Cruickshanks-Boyd DW, Lloyd CH, Main C, McCabe JF, Miller M, Tranter TC, Waters NE, Watts DC, Williams DF, Wilson AD, Wilson HJ. Dental materials: 1978 literature review. Part I. J Dent 1980; 8:189-221. [PMID: 7002966 DOI: 10.1016/0300-5712(80)90074-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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181
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182
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Williams DF. The effect of bacteria on absorbable sutures. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1980; 14:329-38. [PMID: 6245093 DOI: 10.1002/jbm.820140313] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In vitro and in vivo experiments were performed on polyglycolic acid and plain catgut sutures to study the effects of bacteria on their rate of degradation. Experiments with Strep, mites, E. coli and Staph. albus in culture showed that the polyglycolic acid sutures degraded faster in broth controls than in a broth containing bacteria as measured by the loss in breaking strength. No difference was observed with the catgut. Polyglycolic acid sutures in subcutaneous sites in rats inoculated with Staph. albus again degrade slower than in similar wounds which were not deliberately infected. With high bacterial counts, the catgut showed the reverse trend although no differences were noted at lower counts.
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183
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Williams DF. Academic focus: biomaterials activities at the University of Liverpool. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1980; 14:325-7. [PMID: 7364793 DOI: 10.1002/jbm.820140312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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184
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185
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Braden M, Brown D, Miller M, Causton BE, Tranter TC, Combe EC, Waters NE, Cruickshank-Boyd DW, Williams DF, Lloyd CH, Wilson AD, Main C, Wilson HJ. Dental materials: 1977 literature review. Part II. J Dent 1980; 8:43-67. [PMID: 6989870 DOI: 10.1016/s0300-5712(80)80044-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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186
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Williams DF, Bé AW, Fairbanks RG. Seasonal Oxygen Isotopic Variations in Living Planktonic Foraminifera off Bermuda. Science 1979; 206:447-9. [PMID: 17809368 DOI: 10.1126/science.206.4417.447] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Seasonal variations in the oxygen-18/oxygen-16 ratio of calcite shells of living planktonic foraminifera in the Sargasso Sea off Bermuda are a direct function of surface water temperature. Seasonal occurrence as well as depth habitat are determining factors in the oxygen isotopic composition of planktonic foraminifera. These relationships may be used to determine the seasonal temperature contrast of oceans in the past.
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187
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Fünfschilling J, Altwegg L, Zschokke–Gränacher I, Chabr M, Williams DF. The magnetic field dependence of the delayed fluorescence in p‐terphenyl between 130 and 300 K. J Chem Phys 1979. [DOI: 10.1063/1.437296] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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188
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Williams DF, Mares MA. Karyologic Affinities of the South American Big-Eared Bat, Histiotus montanus (Chiroptera, Vespertilionidae). J Mammal 1978. [DOI: 10.2307/1380148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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189
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Williams DF, Mares MA. Karyologic affinities of the South American big-eared bat, Histiotus montanus (Chiroptera, Vespertilionidae). J Mammal 1978; 59:844-6. [PMID: 750638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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190
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Williams DF. Karyological Affinities of the Species Groups of Silky Pocket Mice (Rodentia, Heteromyidae). J Mammal 1978. [DOI: 10.2307/1380236] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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191
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Williams DF, Thunell RC, Kennett JP. Periodic Freshwater Flooding and Stagnation of the Eastern Mediterranean Sea During the Late Quaternary. Science 1978; 201:252-4. [PMID: 17778656 DOI: 10.1126/science.201.4352.252] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Major negative oxygen isotopic anomalies in planktonic foraminifera are associated with deep-sea anoxic mud layers (sapropels) deposited 9000 and 80,000 years ago in the eastern Mediterranean. The isotopic depletion in surface-dwelling foraminifera is significantly greater than in mesopelagic foraminifera. This difference in isotopic response suggests that surface-water salinities were drastically reduced during times of sapropel formation, possibly as the result of meltwater runoff from the Fennoscandian ice sheet into the eastern Mediterranean by way of the Black and Aegean seas.
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193
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Fisher AD, Williams DF, Bradley PF. The effect of cryosurgery on the strength of bone. THE BRITISH JOURNAL OF ORAL SURGERY 1978; 15:215-22. [PMID: 272917 DOI: 10.1016/0007-117x(78)90003-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The effect of cryosurgery on the mechanical properties of bone has been studied by freezing rats' mandibles. The mandibles of laboratory rats were subjected to cryosurgery and tested at 2, 4, 8, 16 and 26 weeks. In comparison to the control contralateral sides, a reduction in strength was recorded at four and eight weeks, the difference being highly significant at eight weeks. This indicates the susceptibility of bone treated by cryosurgery to pathological fracture and suggests that preventive measures may need to be undertaken to minimise this possibility.
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194
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Burshtein Z, Williams DF. Temperature dependence of carrier generation, and transport in para‐terphenyl above and below the 180 °K phase transition. J Chem Phys 1978. [DOI: 10.1063/1.435837] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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195
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Adams D, Williams DF, Hill J. Carbon fiber-reinforced carbon as a potential implant material. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1978; 12:35-42. [PMID: 632315 DOI: 10.1002/jbm.820120104] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A carbon fiber-reinforced carbon is being evaluated as a promising implant material. In a unidirectional composite, high strengths (1200 MN/m2 longitudinal flexural strength) and high modulus (140 GN/m2 flexural modulus) may be obtained with an interlaminar shear strength of 18 MN/m2. Alternatively, layers of fibers may be laid in two directions to give more isotopic properties. The compatibility of the material with bone has been studied by implanting specimens in holes drilled in rat femora. For a period of up to 8 weeks, a thin layer of fibrous tissue bridged the gap between bone and implant; but this tissue mineralizes and by 10 weeks, bone can be observed adjacent to the implant, giving firm fixation. Potential applications include endosseous dental implants where a greater strength in the neck than that provided by unreinforced carbon would be advantageous.
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196
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Anand SC, St John KR, Moyle DD, Williams DF. Stress distribution in porous surfaced medullary implants. Ann Biomed Eng 1977; 5:410-20. [PMID: 607827 DOI: 10.1007/bf02367319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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197
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Burshtein Z, Williams DF. Temperature dependence of electron transport and generation in biphenyl. J Chem Phys 1977. [DOI: 10.1063/1.435358] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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198
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199
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Williams DF. Titanium as a metal for implantation. Part 2: biological properties and clinical applications. J Med Eng Technol 1977; 1:266-70. [PMID: 597549 DOI: 10.3109/03091907709162192] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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200
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Williams DF, Mort E. Enzyme-accelerated hydrolysis of polyglycolic acid. JOURNAL OF BIOENGINEERING 1977; 1:231-8. [PMID: 210160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In a preliminary study of the enzyme-polymer interactions, the role of 15 enzymes in the in vitro hydrolysis of polyglycolic acid has been investigated. Carboxypeptidase A, alpha-chymotrypsin, clostridiopeptidase A and ficin increase the rate of hydrolysis of this synthetic polymer, illustrating the ability of enzymes to influence polymer degradation.
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