This thesis describes a study of the fundamental aspects of banding in steel. The banded structure is simulated by means of layer diffusion couples. Consideration is given to the amount of carbon pre-­segregation that occurs in the austenitic state due to activity differ­ences arising from a non-uniform distribution of alloying elements as well as to the segregation which occurs during subsequent transformation. A new method for the experimental determination of the off-diagonal diffusion coefficients which control the pre-segregation in ternary systems is described. Different cooling rates are used to investigate the contribution of transformation segregation toward the final structure. The effect of cooling rates on the final structure is investigated metallographically. / Thesis / Master of Science (MS)

Process irregularities in remelting furnace operation have an impact on the ingot solidification structure which depends on the local thermal conditions and the alloy concerned. In this work, a laboratory investigation into the structures resulting from interruptions in solid growth is presented in order to understand the cause and effect relationship between the solidification interruption and banding. The results demonstrate the range of structure, segregation and precipitation changes which are experienced by a range of alloys including Inconel 718, Nimonic 80A, Waspaloy andM50. In the case of alloys which form primary precipitates, the interruption period is shown to give rise to structure changes. Segregations are found due to the interruption. We also comment on the differences observed between industrial examples of banding and the laboratory samples which may be due to the absence of liquid movement in the latter technique. It is concluded that the interruption in solidification condition during a directionally solidification itself can produce banding through its effects on the morphology of precipitates.

Process irregularities in remelting furnace operation have an impact on the ingot solidification structure which depends on the local thermal conditions and the alloy concerned. In this work, a laboratory investigation into the structures resulting from interruptions in solid growth is presented in order to understand the cause and effect relationship between the solidification interruption and banding. The results demonstrate the range of structure, segregation and precipitation changes which are experienced by a range of alloys including Inconel 718, Nimonic 80A, Waspaloy andM50. In the case of alloys which form primary precipitates, the interruption period is shown to give rise to structure changes. Segregations are found due to the interruption. We also comment on the differences observed between industrial examples of banding and the laboratory samples which may be due to the absence of liquid movement in the latter technique. It is concluded that the interruption in solidification condition during a directionally solidification itself can produce banding through its effects on the morphology of precipitates.

Thesis (Ph. D.)--Cornell University, 1929. / From Bird-banding, vol. I, no. 4, 1930, and vol. II, no. 1-2, 1931. "Literature cited" at end of each part.

Thesis (Ph. D.)--Cornell University, 1929. / From Bird-banding, vol. I, no. 4, 1930, and vol. II, no. 1-2, 1931. "Literature cited" at end of each part.

Thesis (M.S.)--Oregon State University, 1969. / Includes bibliographical references (leaves 63-65). Also available on the World Wide Web.

Process irregularities in remelting furnace operation have an impact on the ingot solidification structure which depends on the local thermal conditions and the alloy concerned. In this work, a laboratory investigation into the structures resulting from interruptions in solid growth is presented in order to understand the cause and effect relationship between the solidification interruption and banding. The results demonstrate the range of structure, segregation and precipitation changes which are experienced by a range of alloys including Inconel 718, Nimonic 80A, Waspaloy andM50. In the case of alloys which form primary precipitates, the interruption period is shown to give rise to structure changes. Segregations are found due to the interruption. We also comment on the differences observed between industrial examples of banding and the laboratory samples which may be due to the absence of liquid movement in the latter technique. It is concluded that the interruption in solidification condition during a directionally solidification itself can produce banding through its effects on the morphology of precipitates. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

Kraniopharyngeome sind seltene hypothalamische Tumore, die vor allem im Kindes- und Jugendalter auftreten. Bei hohen Überlebensraten ist die Prognose des Tumors gut, jedoch leiden viele Patienten in der Folge unter einer reduzierten Lebensqualität, bedingt durch Schäden des Nervus opticus, Hypophyseninsuffizienz und hypothalamischer Fehlfunktion. Schäden an hypothalamischen Kerngebieten als wichtige Steuerungszentralen der Energiehomöostase führen bei einem Teil der Kraniopharyngeom-Patienten zur Ausbildung einer morbiden Adipositas. Es wird angenommen, dass vor allem eine Fehlfunktion des ventromedialen Hypothalamus zu einer Hyperphagie bzw. einer autonomen Dysregulation mit einer nachfolgenden unkontrollierbaren und stetigen Gewichtszunahme führt. Bisher fehlen etablierte Konzepte über eine adäquate Therapie der kraniopharyngeom-assoziierten hypothalamischen Adipositas. Bei nutritiver morbider Adipositas können bariatrische Eingriffe das Körpergewicht sowie Morbidität und Mortalität anhaltend senken. Auch für junge Kraniopharyngeom-Patienten mit morbider Adipositas erhoffte man sich hier in Ermangelung anderer Optionen einen erfolgreichen Therapieansatz. In Einzelfallberichten zeigten erste Studien vielversprechende Ergebnisse nach Magenband sowie einen effektiven Gewichtsverlust nach Magenbypass. In unserer Studie verglichen wir retrospektiv die Ergebnisse von neun Kraniopharyngeom-Patienten nach Magenbandanlage, sleeve gastrectomy oder Magenbypass mit den Ergebnissen einer Kontrollgruppe, bestehend aus 150 Patienten, davon 46 Patienten mit einem Magenband, 49 Patienten nach einer sleeve gastrectomy und 55 Patienten nach einem Magenbypass. Der Gewichtsverlust der Patienten mit Kraniopharygeom war nach Magenband und sleeve gastrectomy im Vergleich zur Kontrollgruppe signifikant niedriger. Nur nach Anlage eines Magenbypasses waren die Ergebnisse in beiden Gruppen vergleichbar. Wir folgern daraus, dass Verfahren der Adipositas-Chirurgie wie das Magenband und die sleeve gastrectomy keine ausreichende Wirkung zur Reduktion des Übergewichtes bei Kraniopharygeom-Patienten haben. Im Gegensatz dazu könnte der Magenbypass eine geeignete Therapieoption darstellen. Durch die geringe Patientenzahl ist diese Ergebnis unserer Studie jedoch limitiert. Weitere, prospektive Studien mit höheren Fallzahlen sind notwendig, um definitiv zu klären, dass die Bypasschirurgie eine wirksame Therapie der hypothalamischen Adipositas bei Kraniopharygeom-Patienten ist. / Craniopharyngiomas are rare hypothalamic neoplasms, which mostly appear in childhood and adolescence. Survival rates are high, but quality of life is frequently impaired due to alterations of the optic nerve, pituitary gland or hypothalamus. Typically, hypothalamic impairment is followed by rapid onset of morbid obesity (hypothalamic obesity). In the hypothalamic nuclei afferent information from insulin, leptin and ghrelin are translated into signals for hunger, satiety and energy balance. Especially venteromedial hypothalamius dysfunction is believed to promote excessive caloric intake and/or decreased caloric expenditure, leading to continuous and often unrelenting weight gain. Hypothalamic obesity is a devastating condition, which currently lacks an effective treatment. In adults, morbid obesity is associated with increased mortality and health benefits of bariatric surgery are well documented. Because of the pressing need for an effective treatment, bariatric surgery has been postulated also for adolescents with hypothalamic obesity. First experience with laparoscopic adjustable gastric banding (LAGB) was promising and case reports documented effective weight loss after gastric bypass in patients with craniopharyngioma. We retrospectively analysed the effectiveness of bariatric surgery in patients with craniopharyngoma associated morbid obesity. Nine patients we included underwent laparoscopic gastric banding (n = 6), sleeve gastrectomy (n = 4) or gastric bypass surgery (n = 2). Tree patients underwent more than one type of bariatric surgery. 150 persons with common obesity who underwent bariatric surgery served as controls: 46 underwent laparoscopic gastric banding, 49 sleeve gastrectomy and 55 underwent gastric bypass surgery. There was no significant loss of weight in patients with craniopharyngioma after gastric banding and sleeve gastrectomy in contrast to the control group. Significant weight loss was found only in those two patients who received a gastric bypass. Weight loss in these patients was comparable to what was found in the respective control group. In conclusion, our findings in patients with craniopharyngioma associated morbid obesity suggest that both LAGB and sleeve gastrectomy are not as effective as in patients with common obesity and could perhaps only limit further weight gain. Gastric bypass surgery seems to be more effective, but data are still too limited to recommend this procedure without caution in obese craniopharyngioma patients.

Einleitung: Eine präoperative Selektion adipöser Patienten anhand objektiver Kriterien soll entscheidend sein für den Gewichtsverlauf nach Implantation eines Magenbandes (Laparoscopic adjustable gastric banding, LAGB). Es ist unbekannt, ob die präoperative Selektion Auswirkungen auf das Langzeitergebnis des LAGB hat. Material und Methoden: Die vorliegende Studie suchte nach objektiven Variablen mit signifikanter Vorhersagekraft für das Langzeitergebnis des LAGB. Hierfür wurde der Gewichtsverlauf nach LAGB in einem jährlichen Intervall analysiert. 166 Patienten (91,2 %) nahmen an der retrospektiven Studie teil (Lost to Follow-up 8,8 %). Das mediane Follow-up des gesamten Patientenguts betrug 83,1 Monate (Range 0,1 - 177,3 Monate) und endete am Tag des abschließenden Interviews mit den Studienteilnehmern, jedoch spätestens bei ersatzloser Explantation des Magenbandes (Studienende). Eine Per-Protokoll-Analyse untersuchte den Gewichtsverlauf von Patienten ohne ersatzlose Explantation des Magenbandes (N = 111). Der prozentuale Verlust an Übergewicht (Excess Weight Loss, EWL %) am Studienende entschied über das Langzeitergebnis (Success: EWL ≥ 50,0 % mit LAGB, No Success: EWL < 50,0 % mit LAGB oder ersatzlose Explantation des LAGB; Failure: EWL < 20,0 % mit LAGB oder ersatzlose Explantation des LAGB, No Failure: EWL ≥ 20,0 % mit LAGB). Zur Abschätzung von prädiktiven Faktoren hinsichtlich der abhängigen Variablen Success und No Success sowie Failure und No Failure wurde eine binär logistische Regressionsanalyse durchgeführt. Folgende präoperative Kovariaten wurden auf ihren prädiktiven Langzeiteffekt analysiert: Alter, Body-Mass-Index, Übergewicht (Excess Weight), Geschlecht, Adipositas assoziierte Komorbiditäten (Diabetes Mellitus Typ II, arterieller Hypertonus, Schlafapnoe, Gelenkbeschwerden, Belastungsdyspnoe), Bandart (Swedish adjustable gastric banding, Lap Band), Operationstechnik (Pars flaccida, retrogastrisch). Ergebnisse: In der vorliegenden Studie war der EWL (%) im Langzeitverlauf moderat. Der höchste mediane EWL (%) des gesamten Patientenguts wurde im 2. postoperativen Jahr erreicht und betrug 43,2 % (Range -34,1 - 178,8 %) (N = 155). Mit zunehmendem Follow-up sank der EWL (%). Im 5.-, 10.- und 14. postoperativen Jahr betrugen der mediane EWL 39,7 % (Range -39,7 - 162,0 %) (N = 126), 31,0 % (Range -37,6 - 139,7 %) (N = 65) und 31,9 % (Range -34,0 - 108,6 %) (N = 27). Am Studienende wurde am häufigsten ein EWL-Level von 30 - 40 % (12 %, N = 20) erreicht. Prüfkonforme Patienten erreichten am Studienende einen medianen EWL von 33,2 % (Range -81,4 - 116,7 %) (N = 111). Wie bereits in der Literatur berichtet nahmen mit zunehmendem Follow-up die Anteile an Success und No Failure ab. Im 2. postoperativen Jahr betrugen die Success- und No Success-Raten 38,0 % und 62,0 % (Failure: 24,7 %, No-Failure: 75,3 %). Bis zum 10. postoperativen Jahr reduzierte sich der Success-Anteil auf 17,2 % und der No Success-Anteil stieg auf 82,8 % (Failure: 60,9 %, No Failure: 39,1 %). Am Studienende erfüllten 18,7 % (N = 31) der Patienten das Kriterium Success und 81,3 % (N = 135) das Kriterium No Success (Failure: 52,4 %, N = 87; No Failure: 47,6 %, N = 79). Die postoperative Komplikationsrate war hoch, jedoch vergleichbar mit aktuellen Langzeitstudien: 47,6 % (N = 79) der Patienten entwickelten postoperativ eine oder mehrere Band-assoziierte Komplikationen. Slippage (20,5 %, N = 34), Pouchdilatation (20,5 %, N = 34) und Portdislokation/Portdiskonnektion (12,7 %, N = 21) traten am häufigsten auf. 33,1 % (N = 55) der Magenbänder wurden ersatzlos entfernt nach einer medianen Zeit von 40,7 Monaten (Range 0,1 - 163,6 Monate). Diese Studie belegte die positiven Langzeiteffekte des LAGB auf Adipositas-assoziierte Komorbiditäten: 79,4 % (N = 54) der präoperativ hypertonen Patienten und 72,0 % (N = 18) der Patienten mit initialem Diabetes Mellitus Typ II erreichten am Studienende eine Remission und Heilung (Reduktion und Absetzen der Antihypertensiva bzw. Antidiabetika) ihrer Komorbidität. In der Regressionsanalyse fanden sich keine objektiv fassbaren Parameter, die präoperativ ein erfolgreiches Langzeitergebnis nach Implantation eines Magenbandes vorhersagen konnten. Die wichtige präoperative Selektion der Patienten wird dadurch erschwert und basiert somit weiterhin auf eher subjektiven Parametern wie Eindruck der Patienten-Compliance, des patientenseitigen Verstehens der Prozedur sowie Patientenwunsch. LAGB ist heute kein bariatrischer Eingriff der ersten Wahl. Jedoch gibt es Patienten, die aufgrund der potentiellen Reversibilität und geringen Mortalität ein LAGB bevorzugen. Wird heute ein LAGB durchgeführt, erscheint auf Basis der klinischen Erfahrung eine engmaschige Anbindung der Patienten in der postoperativen Nachsorge notwendig, um ein optimales Ergebnis zu erreichen. Bei Versagen des Verfahrens (nicht zufriedenstellender Gewichtsverlauf und/oder Auftreten von Band-assoziierten Komplikationen) sind die Entfernung des Magenbandes und die Umwandlung in ein alternatives adipositaschirurgisches Verfahren zumindest zu diskutieren. / Background: A reasonable preoperative selection of obese patients seems to be important for a successful outcome of laparoscopic adjustable gastric banding (LAGB). It is unknown whether the preoperative selection has influence on the long-term outcome of LAGB. The present study focused on objective predictors of a successful long-term outcome of LAGB, weight loss outcomes and band-related complications. Materials and Methods: Between May 1997 and December 2008, 182 obese patients received a LAGB in the Surgical Department of the Julius-Maximilians-University of Wuerzburg, Germany. Data were collected by retrospective study of the patient files and in a final interview at the end of the follow-up period. Complete weight loss data were collected on 166 patients in a yearly follow-up. 16 patients were lost during follow-up (lost to follow up 8,8 %). The median follow-up of all patients was 83,1 months (range 0,1 - 177,3 months). The follow-up ended on the day of final interview, at latest however on the day of band removal. A separate per-protocol-analysis investigated the weight loss of patients without band removal during the follow-up (n = 111). 166 patients were analysed according to possible predictive characteristics for successful long-term outcome after LAGB. The excess weight loss (EWL %) at the end of the follow-up defined the long-term outcome (success vs. no success, failure vs. no failure): Success was defined as EWL ≥ 50,0 % without band removal, no success as EWL < 50,0 % with LAGB or band removal. Failure was defined as EWL < 20,0 % with LAGB or band removal, no failure as EWL ≥ 20,0 % without band removal. Possible preoperative objective predictors of outcome were age, body mass-index, excess weight, sex, obesity related comorbidities (type 2 diabetes mellitus, arterial hypertension, sleep apnea, joint-disease, dyspnea), type of band (Swedish adjustable gastric banding, Lap Band) and operative technique (pars flaccida, retrogastric). Binary logistic regression analysis was performed using the outcome measure as dependent variable (success vs. no success, failure vs. no failure) and candidates` preoperative features as independent variable. Results: In the present study, the EWL (%) was moderate in the long term. The highest median EWL (%) of all patients was 43,2 % (range -34,1 - 178,8 %) (n = 155) and was reached in the second postoperative year. With increasing follow-up the EWL (%) declined. In the fifth-, tenth- and fourteenth postoperative year the median EWL was 39,7 % (range -39,7 - 162,0 %) (n = 126), 31,0% (range -37,6 - 139,7 %) (n = 65) and 31,9 % (range -34,0 - 108,6 %) (n = 27). At the end of the follow-up the most reached EWL-level was 30 - 40 % (12 %, n = 20). Patients of the per-protocol-analysis reached a median EWL of 33,2 % (range -81,4 - 116,7 %) (n = 111) at the end of the follow-up. As reported in the literature, the success rate and the no failure rate declined progressively with increasing follow-up. In the second postoperative year the success rate and the no success rate were 38,0 % and 62,0 % (failure 24,7 %, no failure 75,3 %). Until the tenth postoperative year, the success rate fell to 17,2 % and the no success rate increased to 82,8 % (failure 60,9 %, no failure 39,1 %). At the end of the follow-up, 18,7 % (n = 31) of all patients met the criterion success and 81,3 % (n = 135) the criterion no success (failure 52,4 %, no failure 47,6 %). The postoperative complication rate was high but comparable with long-term studies: 47,6 % (n = 79) of all patients experienced one or more band-related complications. Slippage (20,5 %, n = 34), pouchdilatation (20,5 %, n = 34) and portdislocation/portdisconnection (12,7 %, n = 21) were the most frequent complications. 33,1 % (n = 55) of the gastric bands were removed without substitution after a median time of 40,7 months (range 0,1 - 163,6 months). This study showed positive long-term effects of LAGB on obesity related comorbidities: 79,4 % (n = 54) of the preoperative hypertensive patients and 72,0 % (n = 18) of the patients with initial type 2 diabetes mellitus had a remission and resolution of the comorbidity at the end of the follow-up. Logistic regression analysis didn´t find objective preoperative parameters that predict a successful long-term outcome after LAGB. The important selection of patients is made difficult and continues to base on subjective parameters (impression of patients` compliance, understanding of the procedure and patients` wish). LAGB is not a first-line option for the surgical treatment of morbid obesity today. However, there are people who prefer LAGB because of its potential reversibility and low mortality. Based on clinical experience, a close postoperative follow-up is necessary to achieve successful long-term results of LAGB. After failure of the procedure (insufficient weight loss or band related complications) surgeons and patients have at least to discuss the band removal and the converting to an alternative obesity surgery procedure.

The ability to accurately identify individuals is required for the detailed study of animals. Numerous artificial markers have been developed for this purpose. Negative effects on survival, reproductive success and behavior have been reported for most marking methods, significantly affecting the very parameters being studied. / Birds of prey have suffered the shortcomings of artificial marking methods. In light of the known and potential deleterious effects of marking, attention has been focused on developing new techniques to identify individual raptors without attaching artificial markers. / This study investigated the use of tarsal scale patterns as unique individual identifiers in birds of prey. The American kestrel (Falco sparverius) was chosen as a model. Both legs of seventy-five kestrels were photographed over a two-year period. / Photographic comparisons of 150 scale patterns demonstrated the uniqueness of each and therefore its ability to be used as an individual's natural identifier. Furthermore, patterns were found to remain unchanged from one year to the next. These findings support the hypotheses that tarsal scale patterns are unique to each bird and do not change over time. / A method of coding the tarsal scale patterns was developed. These codes can be used in a computerized data base to significantly enhance the speed of pattern searches.