Kathy Hightower: A Case Study to Test Your Own Giftedness

Dunn, Rita; Dunn, Kenneth

doi:10.1177/107621757900200204

Cited by 19 publications

(32 citation statements)

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“…Participation of the N-acetyl group in this reaction is indicated by the CH3 observation of Capon that methanolysis of this compound proceeds with retention of configuration at C, (113). Further evidence for kinetically important N-acetyl participation in the hydrolysis of carboxyl-substituted NAGs is provided by the observation that para substitution in 71 yields a positive p value ( t-0.86) for the rate constant pertaining to carboxyl group facilitation (78). The magnitude of p in this instance is consistent with displacement by the N-acetyl group of a protonated phenol in contrast to the p value of +2.…”

Section: F Intramolecular General Acid Catalysis Of Acetal Hydrolysiscontrasting

confidence: 38%

“…The ratio of rate constants for participation by the N-acetyl group and the -OH group (k%E/ksg;;:) is lo3. The plateau rates for the phenyl-p-NAGS obey a Hammett relationship when plotted against (+-and yield a slope of +2.28, indicating that electron withdrawal in the leaving group greatly favors this intramolecular attack (77,78).…”

Section: B Spontaneous Hydrolysismentioning

confidence: 99%

“…The magnitude of p in this instance is consistent with displacement by the N-acetyl group of a protonated phenol in contrast to the p value of +2. observed for displacement of a phenoxide ion (77,78). Furthermore, Piszkiewicz and Bruice noted that although AH: for reaction of (2-carboxyphenyl ) -2'-N-acetyl-2'-deoxy-p-~-glucopyranoside was 4 kcal less than AH1 for (2-carboxyphenyl ) -p-D-glucopyranoside, the entropy of activation was 2 kcal greater for the NAGoside indicating that the reduction in activation energy is partially compensated for by the increased restriction of an additional catalytic group in the transition state (77).…”

Section: F Intramolecular General Acid Catalysis Of Acetal Hydrolysismentioning

confidence: 99%

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Physical Organic Models for the Mechanism of Lysozyme Action

Dunn¹,

Bruice²

1973

Advances in Enzymology - And Related Areas of Molecular Biology

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Section: F Intramolecular General Acid Catalysis Of Acetal Hydrolysiscontrasting

confidence: 38%

Section: B Spontaneous Hydrolysismentioning

confidence: 99%

Section: F Intramolecular General Acid Catalysis Of Acetal Hydrolysismentioning

confidence: 99%

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Physical Organic Models for the Mechanism of Lysozyme Action

Dunn¹,

Bruice²

1973

Advances in Enzymology - And Related Areas of Molecular Biology

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“…A finite-sliding, general contact formulation was adopted for the stent-tissue interactions. A friction coefficient of 0.05 was prescribed among all contact surfaces [20]. Artery and plaque were meshed with 17,784 and 8816 reduced eight-node brick elements (C3D8R), respectively.…”

Section: í/ =mentioning

confidence: 99%

Performance of Self-Expanding Nitinol Stent in a Curved Artery: Impact of Stent Length and Deployment Orientation

Zhao

Froemming

2012

Journal of Biomechanical Engineering

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The primary aim of this work was to investigate the performance of self-expanding Nitinol stents in a curved artery through finite element analysis. The interaction between a PROTÉGÉ™ GPS™ self-expanding Nitinol stent and a stenosed artery, as well as a sheath, was characterized in terms of acute lumen gain, stent underexpansion, incomplete stent apposition, and tissue prolapse. The clinical implications of these parameters were discussed. The impact of stent deployment orientation and the stent length on the arterial wall stress distribution were evaluated. It was found that the maximum principal stress increased by 17.46%, when the deployment orientation of stent was varied at a 5 deg angle. A longer stent led to an increased contact pressure between stent and underlying tissue, which might alleviate the stent migration. However, it also caused a severe hinge effect and arterial stress concentration correspondingly, which might aggravate neointimal hyperplasia. The fundamental understanding of the behavior of a self-expanding stent and its clinical implications will facilitate a better device design.

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“…These authors used HF to remove the film left after chemical polishing. Dunn (6) obtained larger deformations of the metal by rolling anodized metal. A reanodizing technique, which again gave a measure of the area of metal exposed at cracks, indicated large deformation of the oxide.…”

mentioning

confidence: 98%

Adhesion, Ductility, and Fracture of Anodic Oxide Films on Tantalum

Propp

Young

1979

J. Electrochem. Soc.

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Spectrophotometric thickness measurements have confirmed that anodic oxide films on tantalum can show considerable plastic flow when the oxidecoated metal is stretched or rolled, for example up to 15% reduction in the average thickness of oxide. SEM pictures showed that after a certain amount of deformation the oxide cracks and widening areas of "bare" metal develop. The ductile behavior is seen if chemically polished tantalum is etched in HF or treated with boiling water before anodization. Otherwise the fluoride in the film left by chemical polishing modifies the oxidation process in a way which leads to a poorly adherent anodic oxide film.The mechanical properties of oxide films have been considered to be of importance in corrosion situations where the metal is stressed. In such situations, a complication is that the presence of an oxide film can significantly affect the mechanical properties of the metal. A fairly comprehensive list of literature references is given in a recent paper by Choo and Devereux (1). The mechanical properties of thin oxide films can be unexpected by comparison with those of bulk oxide samples. Some years ago (2), one of us reported that anodic oxide films made on tantalum, which had been chemically polished and then pretreated in a certain way before anodization, showed evidence of a surprising degree of ductility, as indicated by a change in interference color when anodized metal foil was stretched in a tensile machine. The pretreatment was immersion in boiling water for a few minutes. Films formed on chemically polished tantalum without pretreatment are very lightly attached to the metal. The pretreatment was based on a guess that fluoride present in the film left by chemical polishing was somehow responsible for the lack of adherence and that it could be replaced by OH' by the pretreatment. The presence of fluoride has been established by Amsel et aL (3). Pawel et al. (4) haveshown that fluoride ions can be incorporated into the oxide from the solution during anodization and can be drifted by the high applied field to the metal where they do indeed then produce poor adhesion. The ductility was confirmed and quantified by Bubar and Vermilyea (5), who used an electrochemical technique to measure the amount of "bare" metal exposed at cracks in the oxide. A redox current was observed corresponding to the tunneling of electrons through the thin oxide in the crack regions. Substantially no such current was observed in some cases up to 9% elongation of the tantalum (Fig. 4, loc. cir.). These authors used HF to remove the film left after chemical polishing. Dunn (6) obtained larger deformations of the metal by rolling anodized metal. A reanodizing technique, which again gave a measure of the area of metal exposed at cracks, indicated large deformation of the oxide. Eliezer and Brandon (7) applied a dry bulge test to windows of anodic film left by selectively removing the metal from behind. They observed only 9 Electrochemical Society Active Member.

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Kathy Hightower: A Case Study to Test Your Own Giftedness

Cited by 19 publications

References 0 publications

Physical Organic Models for the Mechanism of Lysozyme Action

Physical Organic Models for the Mechanism of Lysozyme Action

Performance of Self-Expanding Nitinol Stent in a Curved Artery: Impact of Stent Length and Deployment Orientation

Adhesion, Ductility, and Fracture of Anodic Oxide Films on Tantalum

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