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1

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J-R curve calculation with the normalization method for toughened polymers (1994)

Zhou, Z. ; Landes, J. D. ; Huang, D. D.

Stamford, Conn. [u.a.] : Wiley-Blackwell

Polymer Engineering and Science 34 (1994), S. 128-134

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ISSN: 0032-3888

Keywords: Chemistry ; Chemical Engineering

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics

Notes: The method of normalization is used to develop the J-R curve fracture toughness characterization for polymeric materials. This method can develop J-R curves directly from load vs. displacement records without a need for an on-line crack monitoring system. It was used previously to develop J-R curves for metallic materials and is applied here for the first time to polymer materials. Single edge notched bend specimens of rubber toughened nylon 6/6 and rubber toughened amorphous nylon are used in this study. The J-R curves from the method of normalization are compared with the results obtained from the multiple specimen method of ASTM Standard E813. The results show that the method of normalization gives reasonable J-R curves; both methods show agreement over the early J-R curve region. In addition the JIc values are determined for each method and compared. Based on this work it is suggested that the method of normalization could be used as a general test method to develop J-R curves for polymeric materials.

Additional Material: 10 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pen.760340209

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2

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Nongenomic regulation of extracellular matrix events by vitamin D metabolites (1994)

Boyan, Barbara D. ; Dean, D. D. ; Sylvia, V. L. ; [et al.]

New York, N.Y. : Wiley-Blackwell

Journal of Cellular Biochemistry 56 (1994), S. 331-339

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ISSN: 0730-2312

Keywords: 1,25-(OH)2D3 ; 24,25-(OH)2D3 ; matrix vesicles ; nongenomic regulation ; extracellular matrix ; alkaline phosphatase ; phospholipase A2 ; Protein kinase C ; Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: Vitamin D metabolites appear to regulate chondrocytes and osteoblasts via a combination of genomic and nongenomic mechanisms. Specificity of the nongenomic response to either 1,25-(OH)2D3 or 24, 25-(OH)2D3 may be conferred by the chemical composition of the target membrane and its fluid mosaic structure, by the presence of specific membrane receptors, or by the interaction with classic Vitamin D receptors. Nongenomic effects have been shown to include changes in membrane fluidity, fatty acid acylation and reacylation, arachidonic acid metabolism and prostaglandin production, calcium ion flux, and protein kinaase C activity. Chondrocytes metabolize 25-(OH)D3 to 1,25-(OH)2D3 and 24,25-(OH)2D3; production of these metabolites is regulated by both growth factors and hormones and is dependent on the state of cell maturation. 1,25-(OH)2D3 and 24,25-(OH)2D3 may interact directly with extracellular matix vesicles to regulate their function in the matrix, including protease activity, resulting in matrix modefication and calcification. Isolated matrix vesicles, produced by growth zone chondrocytes, can activate latent transforming growth factor-β when incubated with exogenous 1,25-(OH)2D3. These observations suggest that nongenomic regulation of martix vesicle structure and function may be a mechanism by which mesenchymal cells, like osteoblasts and chndrocytes, may modulate events in the extracellular matrix at sites distant from the cell surace.

Additional Material: 3 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcb.240560309

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3

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Torsional properties of healed canine diaphyseal defects grafted with a fibrillar collagen and hydroxyapatite/tricalcium phosphate composite (1994)

Zardiackas, Lyle D. ; Teasdall, Robert D. ; Black, R. John ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Biomaterials 5 (1994), S. 277-283

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ISSN: 1045-4861

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Medicine , Technology

Notes: The need for alternatives to autogenous bone grafts is widely recognized. This study compared the torsional strength of canine femora 1 year after grafting with one of three forms of a collagen/hydroxyapatite/tricalcium phosphate bone grafting material (COLLAGRAFT15), autogenous bone, or no graft. The groups were compared to each other and to the unoperated contralateral femora. Results of torsional testing were evaluated for torsional strength, torsional displacement, total energy to fracture and White fracture mode. Data analysis showed lower torsional strength of the operated vs. unoperated femora with the exception of morsellized COLLAGRAFT15 material, which had higher strength. However, the only difference in the operated groups was that the morsellized COLLAGRAFT15 had greater strength than several groups including the autogenous bone group. There was no difference found in angular displacement between any of the groups. However, there was a difference in the energy to fracture in both strip forms of the COLLAGRAFT15. The final conclusion is that in this model, grafting with COLLAGRAFT15 provided torsional properties at one year postoperatively at least equivalent to autogenous bone. © 1994 John Wiley & Sons, Inc.

Additional Material: 8 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jab.770050402

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4

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Fracture of porous polyethylene-bone composite (1983)

Mayer, R. D. ; Moyle, D. D. ; Sauer, B. W.

Hoboken, NJ : Wiley-Blackwell

Journal of Biomedical Materials Research 17 (1983), S. 59-70

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ISSN: 0021-9304

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Medicine , Technology

Notes: Porous high-density polyethylene specimens were implanted in the femurs of mongrel canines. At the end of the residency period (3 or 6 months), the animals were sacrificed and the implants were retrieved. The work-of-fracture of the implant specimens was then determined using the technique of Tattersall and Tappin. The work required to fracture a specimen in three-point bending by controlled crack propagation through a triangular cross section was obtained directly from the load-deflection curve. The area of the resulting fracture surface was measured by macro-photographic techniques, and the work-of-fracture was calculated as work per unit area. The implants were subsequently sectioned and examined microradiographically to determine the extent of bone ingrowth. Bone specimens adjacent to the implants and porous high-density polyethylene controls (no ingrowth) were also tested to determine their work-of-fracture. The results showed that bone adjacent to the implant specimens had a higher work-of-fracture than normal medial, canine femoral bone and was not appreciably different from the composite. The work-of-fracture of porous high-density polyethylene was not significantly increased by an increase in bone infiltration, and this anomalous behavior was attributed to a degradation of the polyethylene during implant residence. Control studies supported this hypothesis.

Additional Material: 7 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jbm.820170106

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Metal ion concentrations in retrieved polyethylene total hip inserts and implications for artifactually high readings in tissue (1994)

Meldrum, Russell D. ; Bloebaum, Roy D. ; Dorr, Lawrence D.

Hoboken, NJ : Wiley-Blackwell

Journal of Biomedical Materials Research 28 (1994), S. 405-405

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ISSN: 0021-9304

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Medicine , Technology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jbm.820280316

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Identification and quantification of Cu contamination on GaAs surfacesPaper presented at QSA 7, Guildford, September 1992. (1994)

Sykes, D. E. ; Chew, A. ; Hall, D. D. ; [et al.]

Chichester [u.a.] : Wiley-Blackwell

Surface and Interface Analysis 21 (1994), S. 51-55

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ISSN: 0142-2421

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Physics

Notes: Secondary ion mass spectrometry has been used to identify the presence of Cu contamination on undoped semiinsulating GaAs wafer surfaces following polishing under certain conditions. The presence of a contaminating species on the wafer surface is indicated by the influence of pre-etch treatments on electrical measurements performed on heat-treated wafers, with and without Si implants. The identification of Cu as a contaminant is confirmed by photoluminescence measurements. With the appropriate wafer preparation process, the level of Cu contamination is below the SIMS detection limit of 〈1 × 1016 atoms cm-3.In the SIMS analysis of the surface-contaminated wafers, the Cu depth profile shape was dependent on the primary beam bombardment energy, suggesting a chemical segregation of Cu out of the altered layer, a redistribution that is known to occur in Si.To quantify the surface concentration of Cu, GaAs wafers were deliberately contaminated with Cu, heat treated and analysed with glow discharge mass spectrometry and SIMS to provide a cross-calibration.

Additional Material: 5 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/sia.740210108

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7

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Theory of fire and fire processes (1983)

Rasbash, D. J. ; Drysdale, D. D.

New York, NY [u.a.] : Wiley-Blackwell

Fire and Materials 7 (1983), S. 79-88

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ISSN: 0308-0501

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Architecture, Civil Engineering, Surveying , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: There are two major fire processes, an understanding of which is essential for effective fire safety design: (1) the conditions under which a combustible material may become involved in flaming combustion, and (2) the rate at which such a material, once involved, will provide an output of heat, smoke, toxic gases, etc., which can endanger people and property. The first process may be regarded as covering both ignition and spread of fire on materials; its complement is the way in which fire may become extinguished. It is necessary for such processes to bring in a characteristic of the basic combustion reaction which, directly or indirectly, expresses the reactivity of the combustion process. Thus pilot ignition is usually associated with an approximate surface fuel temperature. More basically, it is associated with a critical flow rate of volatiles and a critical heat loss from the flame, the latter being influenced by ambient oxygen and temperatures conditions as well as heat lost and gained by the fuel itself. The most important factor governing the production of dangerous product is the rate at which volatiles first (fuel controlled fires) and later air (air controlled fires) are fed into the flames. The reactivity is of less importance, although it may be one of the factors which control combustion efficiency. In general, the more efficient is the combustion the more heat is produced, but the less smoke and toxic gases are produced. Some of the main advances in the above areas are reviewed in this paper.

Additional Material: 2 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/fam.810070206

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8

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Increase in copy number of an integrated vector during continuous culture of Hansenula polymorpha expressing functional human haemoglobin (1994)

Gilbert, S. C. ; van Urk, H. ; Greenfield, A. J. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Yeast 10 (1994), S. 1569-1580

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ISSN: 0749-503X

Keywords: Hansenula ; haemoglobin ; integration ; continuous culture ; Life and Medical Sciences ; Genetics

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology

Notes: Recombinant human haemoglobin A (rHbA) was produced by a leucine-requiring strain of Hansenula polymorpha which had been transformed with an integration vector containing the Saccharomyces cerevisiae LEU2 gene and cDNAs for the expression of α and β globin each driven by the H. polymorpha MOX promoter. After 40 generations in a chemostat it was found that the integrated vector had become amplified in the host strain. In some cases this led to an increase in LEU2 gene dosage, but a loss of globin expression cassettes. In other cases the globin gene dosage also increased. These changes coincided with an increase in rHbA production in the culture, which was reversed when the dilution rate was increased. Isolates from a chemostat culture producing elevated levels of rHbA were grown in fed-batch fermentations, resulting in higher productivities than when inoculated with the parent strain. The rHbA produced was purified and characterized. Oxygen binding studies and electrospray mass spectrometry showed that the rHbA had been processed and assembled correctly, and behaved as a fully functional co-operative tetramer.

Additional Material: 7 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/yea.320101206

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9

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Triazine-based polymers, 2. Synthesis and characterization of polyethers (1994)

Braun, D. ; Most, D. ; Ziser, T.

Weinheim : Wiley-Blackwell

Angewandte Makromolekulare Chemie 221 (1994), S. 187-205

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ISSN: 0003-3146

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Description / Table of Contents: Polyether auf Triazinbasis können mittels phasentransferkatalysierter Polykondensation bei Raumtemperatur und Reaktionszeiten von 1 bis 3 h hergestellt werden. Von mehr als 20 Polyethern wurden Löslichkeiten, Glasübergangstemperaturen, thermogravimetrische Daten, Reißdehnungen, Reißfestigkeiten, Elastizitätsmoduli und Schlagzähigkeiten bestimmt. Von den Polymeren aus 2,4-Dichlor-6-diethylamino-s-triazin und Bisphenol A wurde zusätzlich der Kristallisationsgrad mittels Röntgenweitwinkelstreuung ermittelt. Das Inkrement des 1,3,5-Triazintriylrings wurde bestimmt, so daß die Glastemperaturen einiger Polyether nach van Krevelen berechnet werden konnten.

Notes: Triazine-based polyethers can be synthesized by phase transfer catalysed interfacial polycondensation at room temperature and reaction times of about 1 to 3 h. In this way, more than 20 polyethers were synthesized and solubilities, glass transition temperatures, thermogravimetric data, elongations at break, tensil strengths, elasticity moduli and impact strengths were determined. In addition, the degree of crystallinity was investigated for the polymer obtained from of 2,4-dichloro-6-diethylamino-s-triazine and bisphenol A by wide angle X-ray diffraction. The increment of the 1,3,5-triazinetriyl ring was determined, which made it possible to calculate the glass transition temperatures of some polyethers according to van Krevelen.

Additional Material: 1 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/apmc.1994.052210116

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Conformational analysis of acetyl-L-phenylalanine p-acetyl and p-valeryl anilides (1983)

Petkov, D. D. ; Ivanov, P. M. ; Stoineva, I. B.

New York : Wiley-Blackwell

Biopolymers 22 (1983), S. 1489-1498

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ISSN: 0006-3525

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Empirical force-field calculations and ir and 1H-nmr spectra indicate that five-membered (C5) and seven-membered (C7eq) hydrogen-bonded rings are the preferred conformations of acetyl-L-Phe p-acetyl and p-valeryl anilides in nonpolar media. The C5/C7eq ratio was found to be dependent on the dryness of the solute and the solvent. This fact and the results from conformational-energy calculations suggest that a molecule of water participates in the stabilization of the C7eq conformation.

Additional Material: 4 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/bip.360220605

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