Free flap reconstruction and implant-based dental rehabilitation in oral cancer patients

Chapter 2 retrospectively investigated postoperative complications (POC) in patients who had undergone primary free flap reconstructions after surgical treatment of oral cancer. Surgical complications occurred in 32% of the patients and systemic complications occurred in 8% of the patients. Prolonged anaesthesia time and red cell transfusion were associated with systemic complications and prolonged hospital stay, respectively. Although both variables are difficult to modify, these may create awareness during the postoperative course and may be informative in the preoperative phase for patient selection and during the informed consent process. Chapter 3 gives an estimation of the occurrence of symptomatic venous thromboembolism (VTE) in 233 surgical oral cancer patients. Despite almost all patients (97%) were classified as having the highest risk for VTE, the occurrence of VTE in surgical oral cancer patients seems to be rare, if thromboprophylaxis is used (overall incidence: 0.4 %). We could not recommend the use of routine thromboprophylaxis as there was no control group without thromboprophylaxis. Therefore, thromboprophylaxis could be advocated in patients with obvious and serious risk factors. Chapter 4 focused on POCs in patients who had undergone reconstruction of segmental mandibular defects with free fibula flaps after surgical ablation of oral cancer. During the first year, POCs occurred in 47 patients (54.7%). Twenty-eight patients (32.6%) had surgical complications, 10 patients (11.6%) had systemic complications and 9 patients (10.5%) had surgical and systemic complications. Active smoking, mandibular reconstruction in the symphyseal region, and TNM anatomic stage group>II were associated with surgical complications. Age>60 years and a Charlson Comorbidity Index (CCI)>2 were identified as predictive factors for systemic complications. With exemption of smoking habits, most variables are relatively unchangeable and its clinical value is mostly informative regarding risk stratification and it may be helpful during the informed consent process and for selecting surgical patients. In Chapter 5 a retrospective study is described on head and neck cancer patients who had undergone implant-based dental rehabilitation after jaw reconstruction with a fibula free flap. In total, 161 dental implants were placed secondarily in 44 fibula free flaps. The implant survival was significantly different in irradiated fibula free flaps (55%) compared to the implant survival in non-irradiated fibula free flaps (96%). Implant-based dental rehabilitation was started 45 times in 42 patients, out of 150 patients. Three patients underwent a second attempt after the initial fibula graft was lost. In 37 patients dental rehabilitation was completed of whom 29 eventually functioned satisfactory. Irradiation of the fibula free flap and cigarette smoking seemed to be significant predictors for dental implant failure and attainment of functional dental rehabilitation. Having both risk factors simultaneously may be associated with an extreme high risk for dental implant failure and necrosis of the fibula free flap. Chapter 6 evaluated the effect of implant-based dental rehabilitation on the health-related quality of life (HRQoL) in head and neck cancer patients who had undergone reconstruction with a fibula free flap. HRQoL was evaluated with the EORTC QLQ-C30 and EORTC QLQ-H&N 35 in 19 patients who had undergone implant-based dental rehabilitation and 38 patients who had not. HRQoL did not seem to substantially change after completing implant-based dental rehabilitation compared to baseline values, as weight loss was the only domain that reached significance in the within-subject analysis. When the mean changes of all the EORTC QLQ-C30 and EORTC QLQ-H&N35 scores were analysed in both groups, no significant differences could be found in the course of HRQoL for those who had undergone implant-based dental rehabilitation compared to those who had not. Patients should be preoperatively informed regarding this finding to have realistic expectations regarding the outcomes of this additional treatment

The oxidative reforming of methane to synthesis gas on a commercial steam reforming catalyst

The oxidative reforming of methane to predominantly carbon monoxide and hydrogen was studied over a commercial steam reforming catalyst. The said reaction was performed in an integral fixed-bed reactor at temperatures between 575°C and 650°C at a total pressure of 200 kPa(a). The primary objective of the study was the design and construction of equipment to facilitate firstly, the measurement of axial bed temperature profiles, and secondly, the investigation of transport effects during the oxidative reforming of methane. The absence of internal or external temperature- and concentration gradients were tested by subjecting the experimental results to theoretical criteria that had previously been derived to check for transport limitations. In all cases the correlations confirmed that the experimental system was free of transport resistances. Having obtained differential reaction rates from the integral data, two LangmuirHinshelwood models were developed and fitted to the data. The model which was derived from the assumption that methane adsorption on a single active site was the rate-determining step, gave the best fit to the experimental data. Adsorption constants correlated in broad terms with the reaction orders of the species which were previously determined by the method of initial rates. The differential kinetic data that were obtained from the fitting of exponential curves to the integral data gave the best correlation between predicted and measured reaction rates. Subsequent to the differential treatment of the data, an attempt was made to correlate the integral data by means of an integral reaction model. A combination of the total oxidation-, oxidative reforming- and steam reforming of methane, as well as the water-gas shift reaction, resulted in the best fit between measured- and predicted data. The predicted methane, carbon monoxide- and hydrogen partial pressures correlated well with experimental data, but that of oxygen, carbon dioxide and water were less accurately predicted by the model. The lack of any comparable study in the literature made it impossible to compare adsorption- and rate constants to other work. X-ray diffraction results showed that the active catalyst bed consisted of a top layer of nickel oxide on alumina and zero-valent nickel on alumina deeper into the bed. Evidence from thermogravimetric experiments revealed that carbon formation was inhibited by H2 cofeeding and high 0 2 inlet partial pressures, but that it was enhanced by CO co-feeding

Interpreting the Interpreters : a Critical Analysis of the Interaction Between Formalism and Transformative Adjudication in Namibian Constitutional Jurisprudence 1990 - 2004

The Security Council of the United Nations adopted Resolution 629 on 16 January 1999, preparing the way for supervised elections and independence for Namibia. A Constituent Assembly elected through a United Nations-supervised election, drafted the Constitution. Namibia became independent from South Africa on 21 March 1990. The dissertation analyses the constitutional judgments of the Supreme and High Courts of Namibia. The interpretive and jurisprudential theories of interpretation of the Namibian superior courts are analyzed. Special attention is given to a post-modern approach known in southern Africa as transformative constitutionalism, developed by American scholar Karl Klare. Klare bases his theory on the proposition that a post-modern constitution cannot be fully understood by using liberal tools or theories of interpretation. University of Cape Town scholar and High Court judge Dennis Davis and his co-worker S Woolman, has a similar approach as Klare and in an enlightening manner refer to the South African constitution as a creole liberal document. The dissertation identifies the Namibian constitution with what Klare calls a post-modern constitution and Davis/Woolman a creole liberal document. While no Namibian court has used the phrases post-modern or creole liberal with reference to the Namibian Constitution, the dissertation identifies several High and Supreme Court judgments where an interpretive model is used that fits the Klare/Davis/Woolman model. The dissertation compares these judgments with other judgments where the superior courts followed the traditional positivist approach. It concludes that both models are part of the Namibian jurisprudential development between independence and 2004. The Supreme Court, the highest court in Namibia, is yet to give an interpretive authority to any of the models. The Namibian legal system follows a strict reliance on the stare decisis rule, which means that the decisions of the Supreme Court are final and binding on government and all the other courts in Namibia. The dissertation identifies several cases where the High Court initially opted for a conservative and/or positivist approach in interpreting rights or freedoms, while the Supreme Court overturned the judgment with a transformative interpretation. The well-known Kauesa case is a good example. The High Court ruled that the freedoms listed in the Constitution are subjected to the laws of Namibia and that dignity is the â highestâ protected right. The Supreme Court rejected the idea that any constitutional right or freedom can be limited by another Namibian law. It also rejected an interpretation seeing rights and freedoms as a pyramid with dignity on top and all the freedoms at the bottom. The Supreme Court opted for a interpretation grounded in the theory of transformative constitutionalism. Freedoms and rights are not organized as a pyramid, but rather a horizontal line of equally important rights and freedoms. The preferential right or freedom needs to be identified in every case depending on the broadest protection of the individual. But, the dissertation points out, there are also cases where the High Court gave a transformative interpretive judgment just to be overturned by a conservative or positivist judgment of the Supreme Court. The well-known Frank case is aq case in point. The High Court found that the word â sexâ as a non-discriminatory category in Artice 10 of the Constitution, also includes sexual orientation. The Supreme Court overturned the judgment by ruling that the word â sexâ only refers to male and female and has nothing to say about sexual orientation. Finally the dissertation concludes that transformative constitutionalism, while not the only interpretive model adhere to by the Namibian superior courts, has been acknowledge as a good model giving the freedoms and rights in the Constitution a broad interpretation, and well-defined protection to Namibians

Wave and tidal power review

A review of the technology of useful conversion of wave power and tidal power is presented. These two power resources are reviewed separately, but on the same basis: principles of operation, existing devices or plants and research and development. Promising wave power devices in Britain, the United States and Europe are discussed. If wave power is to be competitive, one of the first requirements may be energy densification. Proposed energy densification schemes include resonance, high pressure water and wave focussing. Wave focussing is a Norwegian invention, technically feasible, and although more research and development is required, it appears to be more promising than alternative forms of wave power utilisation. According to a preliminary cost analysis, it could be competitive with conventional hydro-electric power. The large scale exploitation of tidal power has been considered seriously for about half a century; the literature on the topic is voluminous. The main limitations of tidal power are its intermittent nature and the high costs involved in the construction of a plant. The existing pilot plants at the Rance and Kislaya Guba have respectively proved that tidal power is technically feasible and that construction costs could be reduced. With the rapid increase in the price of fossil fuels, tidal power plants may be realised at the two best sites in the world, the Bay of Fundy and the Severn Estuary

Speaking of fragrance

Thesi