9 resultados para Membrane-covered self-expanding metal stent (SEMS)
em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland
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Aims: This study was carried out to evaluate surgical treatment of colorectal cancer (CRC) with special interest in present status and controversial issues: stenting as a palliative procedure for metastasized CRC (I), duration of thromboprophylaxis after the surgical treatment of CRC (II), treatment of the increasing population of elderly people (III) and the quality of life (QoL) after surgery for rectal cancer with special reference to pelvic floor dysfunction (IV). Materials and methods: The material consisted of patients with CRC operated on at Turku University Hospital between 2003 and 2008. In study II the data was collected retrospectively from electronic archives. In other studies the follow-up data was collected at postoperative control visits. In study IV the RAND-36 standardized questionnaire and additional questions assessing urinary, sexual and anorectal dysfunction were used. Results: The results of the current study showed that self-expanding metallic stents provided an alternative to palliative surgery in the treatment of obstructive CRC. Low molecular heparin given s.c. for a median of 11 days until hospital discharge seemed to provide sufficient thromboprophylaxis after surgery. With preoperative selection elderly patients with rectal cancer were suitable for major surgery for rectal cancer with morbidity and mortality rates comparable to those in younger patients. There was no difference between preoperative and one year postoperative general QoL for operated rectal cancer patients. Postoperative pelvic dysfunction was associated with an impaired QoL in some dimensions. Conclusions: Many individual factors regarding the patient and the disease must be taken into account when making treatment decisions in CRC to ensure successful treatment of CRC, patient satisfaction and QoL.
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This report illustrates a comparative study of various joining methods involved in sheet metal production. In this report it shows the selection of joining methods, which includes comparing the advantages and disadvantages of a method over the other ones and choosing the best method for joining. On the basis of various joining process from references, a table is generated containing set of criterion that helps in evaluation of various sheet metal joining processes and in selecting the most suitable process for a particular product. Three products are selected and a comprehensive study of the joining methods is analyzed with the help of various parameters. The table thus is the main part of the analysis process of this study and can be advanced with the beneficial results. It helps in a better and easy understanding and comparing the various methods, which provides the foundation of this study and analysis. The suitability of the joining method for various types of cases of different sheet metal products can be tested with the help of this table. The sections of the created table display the requirements of manufacturing. The important factor has been considered and given focus in the table, as how the usage of these parameters is important in percentages according to particular or individual case. The analysis of the methods can be extended or altered by changing the parameters according to the constraint. The use of this table is demonstrated by pertaining the cases from sheet metal production.
Resumo:
In this thesis the membrane filtration equipment for plate type ceramic membranes was developed based on filtration results achieved with different kinds of wastewaters. The experiments were mainly made with pulp and board mill wastewaters, but some experiments were also made with a bore well water and a stone cutting mine wastewater. The ceramicmembranes used were alpha-alumina membranes with a pore size of 100 nm. Some ofthe membranes were coated with a gamma-alumina layer to reduce the membrane pore size to 10 nm, and some of them were modified with different metal oxides in order to change the surface properties of the membranes. The effects of operationparameters, such as cross-flow velocity, filtration pressure and backflushing on filtration performance were studied. The measured parameters were the permeateflux, the quality of the permeate, as well as the fouling tendency of the membrane. A dynamic membrane or a cake layer forming on top of the membrane was observed to decrease the flux and increase separa-tion of certain substances, especially at low cross-flow velocities. When the cross-flow velocities were increased the membrane properties became more important. Backflushing could also be used to decrease the thickness of the cake layer and thus it improved the permeate flux. However, backflushing can lead to a reduction of retentions in cases where the cake layer is improving them. The wastewater quality was important for the thickness of the dynamic membrane and the membrane pore size influenced the permeate flux. In general, the optimization of operation conditions is very important for the successful operation of a membrane filtration system. The filtration equipment with a reasonable range of operational conditions is necessary, especiallywhen different kinds of wastewaters are treated. This should be taken into account already in the development stage of a filtration equipment.
Resumo:
Tässä diplomityössä tutkittiin keraamisten mikrosuodatuskalvojen soveltuvuutta kiintoaineen erottamiseen happamasta PLS-liuoksesta eri huokoskoon omaavilla mikrosuodatuskalvoilla. Koelaitteistolla suodatettiin puhdasta vettä, kaoliinipitoista vesiliuosta sekä hapanta kuparia, kalsiumia ja kaoliinia sisältävää malliliuosta. Koeajojen tavoitteena oli saada tietoa permeaattivuon maksimimäärästä eri mikrosuodatuskalvoilla sekä tuotteen puhtaudesta. Näiden lisäksi saatiin tietoa kalvojen likaantumisesta ajon aikana. Teoriaosassa käsiteltiin yleisesti kalvosuodatusta, esitettiin yleiset kalvotekniset menetelmät ja sovellukset sekä käytiin läpi tutkimuksia samankaltaisiin kalvoihin ja sovelluksiin liittyen. Lisäksi teoriaosuudessa pohdittiin mahdollisuutta käyttää myös muita, kuin putkimoduulisia mikrosuodatuskalvoja. Myös työhön oleellisena taustana kuuluvaa hydrometallurgiaa tarkasteltiin teoreettiselta kannalta. Puhtaan veden suodatuskoetuloksista havaittiin, että kaikki kalvot jäivät selvästi valmistajan ilmoittamista arvoista. 1,0 µm CoMetas CoMem® kalvon teoreettinen vesivuo on 10 m3/(h bar) ja 3,0 µm CoMetas CoMem® teoreettinen vesivuo on yli 50 m3/(h bar). Näistä parhaimman vuon arvon sai 1,0 µm CoMetas CoMem® mikrosuodatuskalvo. Tämä kalvo oli paras sekä veden suodatuksissa että malliliuoksella tehdyillä suodatuksilla. Malliliuoksella saavutettiin n. 2000 L/(m2 h) paineen ollessa 2,0 bar ja virtausnopeuden ollessa 4,4 m/s. Vastaavat vesiajon tulokset olivat n. 1100 L/(m2 h) paineen ollessa 1,0 bar ja virtausnopeuden 2,9 m/s. Kaikki kolme käytettyä kalvoa pidättivät kaoliiniliuoksen 81–100 %:sesti. Kuparipitoista malliliuosta suodatettaessa pystyttiin vastaavasti erottamaan 77–99 % kiintoaineesta. Koeajoissa kuitenkin havaittiin huomattava vuon arvojen putoaminen, joka johtui kalvon likaantumisesta. Huomioitavaa oli kuitenkin, että hapanta malliliuosta suodatettaessa permeaattivuon arvot olivat kaoliiniliuoksen suodatuksessa saatuja vastaavia arvoja korkeammat.
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This study explores areas which need to be improved to develop the quality of patient education to support self-management of patients with mental illness in psychiatric hospitals. The study was conducted in five phases during the period 2000 – 2007. First, patients‘ (n = 313) satisfaction with patient education were investigated. Second, patients' (n = 51) experiences of patient education were explored. Third, a national survey was conducted to investigate realisation of patient education from the staff (n = 55) viewpoint. Fourth, outcomes of patient education were investigated by evaluating the impacts of different patient education methods on patients‘ (n = 311) attitudes towards medication, knowledge level and importance of information. Fifth, patients‘ (n = 16) perceptions of different patient education methods were explored. Patients reported poor satisfaction with patient education (Phase I), and they have considerable need to receive information during their hospital stay (Phase II). Described by staff, the content of patient education covered almost all informational areas investigated. However, discrepancies related to the realisation of patient education were found. (Phase III.) Evaluation of different patient education methods indicate that patients derived benefits from structured patient education with supportive methods (Phase IV) and patients also perceived that these methods supported their information receiving (Phase V). In order to improve the quality of patient education to support self-management of patients with mental illness patient education should be systematically and individually provided to all patients by using different educational methods. Realisation of this should be ensured by providing written instructions, improving nurses‘ knowledge and skills as well ensuring operating conditions.
Resumo:
In the theory part the membrane emulsification was studied. Emulsions are used in many industrial areas. Traditionally emulsions are prepared by using high shear in rotor-stator systems or in high pressure homogenizer systems. In membrane emulsification two immiscible liquids are mixed by pressuring one liquid through the membrane into the other liquid. With this technique energy could be saved, more homogeneous droplets could be formed and the amount of surfactant could be decreased. Ziegler-Natta and single-site catalysts are used in olefin polymerization processes. Nowadays, these catalysts are prepared according to traditional mixing emulsification. More homogeneous catalyst particles that have narrower particle size distribution might be prepared with membrane emulsification. The aim of the experimental part was to examine the possibility to prepare single site polypropylene catalyst using membrane emulsification technique. Different membrane materials and solidification techniques of the emulsion were examined. Also the toluene-PFC phase diagram was successfully measured during this thesis work. This phase diagram was used for process optimization. The polytetrafluoroethylene membranes had the largest contact angles with toluene and also the biggest difference between the contact angles measured with PFC and toluene. Despite of the contact angle measurement results no significant difference was noticed between particles prepared using PTFE membrane or metal sinter. The particle size distributions of catalyst prepared in these tests were quite wide. This would probably be fixed by using a membrane with a more homogeneous pore size distribution. It is also possible that the solidification rate has an effect on the particle sizes and particle morphology. When polymeric membranes are compared PTFE is probably still the best material for the process as it had the best chemical durability.
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Bio-ethanol has been used as a fuel additive in modern society aimed at reducing CO2-emissions and dependence on oil. However, ethanol is unsuitable as fuel supplement in higher proportions due to its physico-chemical properties. One option to counteract the negative effects is to upgrade ethanol in a continuous fixed bed reactor to more valuable C4 products such as 1-butanol providing chemical similarity with traditional gasoline components. Bio-ethanol based valorization products also have other end-uses than just fuel additives. E.g. 1-butanol and ethyl acetate are well characterised industrial solvents and platform chemicals providing greener alternatives. The modern approach is to apply heterogeneous catalysts in the investigated reactions. The research was concentrated on aluminium oxide (Al2O3) and zeolites that were used as catalysts and catalyst supports. The metals supported (Cu, Ni, Co) gave very different product profiles and, thus, a profound view of different catalyst preparation methods and characterisation techniques was necessary. Additionally, acidity and basicity of the catalyst surface have an important role in determining the product profile. It was observed that ordinary determination of acid strength was not enough to explain all the phenomena e.g. the reaction mechanism. One of the main findings of the thesis is based on the catalytically active site which originates from crystallite structure. As a consequence, the overall evaluation of different by-products and intermediates was carried out by combining the information. Further kinetic analysis was carried out on metal (Cu, Ni, Co) supported self-prepared alumina catalysts. The thesis gives information for further catalyst developments aimed to scale-up towards industrially feasible operations.
Resumo:
University of Turku, Faculty of Medicine, Department of Cardiology and Cardiovascular Medicine, Doctoral Programme of Clinical Investigation, Heart Center, Turku University Hospital, Turku, Finland Division of Internal Medicine, Department of Cardiology, Seinäjoki Central Hospital, Seinäjoki, Finland Heart Center, Satakunta Central Hospital, Pori, Finland Annales Universitatis Turkuensis Painosalama Oy, Turku, Finland 2015 Antithrombotic therapy during and after coronary procedures always entails the challenging establishment of a balance between bleeding and thrombotic complications. It has been generally recommended to patients on long-term warfarin therapy to discontinue warfarin a few days prior to elective coronary angiography or intervention to prevent bleeding complications. Bridging therapy with heparin is recommended for patients at an increased risk of thromboembolism who require the interruption of anticoagulation for elective surgery or an invasive procedure. In study I, consecutive patients on warfarin therapy referred for diagnostic coronary angiography were compared to control patients with a similar disease presentation without warfarin. The strategy of performing coronary angiography during uninterrupted therapeutic warfarin anticoagulation appeared to be a relatively safe alternative to bridging therapy, if the international normalized ratio level was not on a supratherapeutic level. In-stent restenosis remains an important reason for failure of long-term success after a percutaneous coronary intervention (PCI). Drug-eluting stents (DES) reduce the problem of restenosis inherent to bare metal stents (BMS). However, a longer delay in arterial healing may extend the risk of stent thrombosis (ST) far beyond 30 days after the DES implantation. Early discontinuation of antiplatelet therapy has been the most important predisposing factor for ST. In study II, patients on long-term oral anticoagulant (OAC) underwent DES or BMS stenting with a median of 3.5 years’follow-up. The selective use of DESs with a short triple therapy seemed to be safe in OAC patients, since late STs were rare even without long clopidogrel treatment. Major bleeding and cardiac events were common in this patient group irrespective of stent type. In order to help to predict the bleeding risk in patients on OAC, several different bleeding risk scorings have been developed. Risk scoring systems have also been used also in the setting of patients undergoing a PCI. In study III, the predictive value of an outpatient bleeding risk index (OBRI) to identify patients at high risk of bleeding was analysed. The bleeding risk seemed not to modify periprocedural or long-term treatment choices in patients on OAC after a percutaneous coronary intervention. Patients with a high OBRI often had major bleeding episodes, and the OBRI may be suitable for risk evaluation in this patient group. Optical coherence tomography (OCT) is a novel technology for imaging intravascular coronary arteries. OCT is a light-based imaging modality that enables a 12–18 µm tissue axial resolution to visualize plaques in the vessel, possible dissections and thrombi as well as, stent strut appositions and coverage, and to measure the vessel lumen and lesions. In study IV, 30 days after titanium-nitride-oxide (TITANOX)-coated stent implantation, the binary stent strut coverage was satisfactory and the prevalence of malapposed struts was low as evaluated by OCT. Long-term clinical events in patients treated with (TITANOX)-coated bio-active stents (BAS) and paclitaxel-eluting stents (PES) in routine clinical practice were examined in study V. At the 3-year follow-up, BAS resulted in better long-term outcome when compared with PES with an infrequent need for target vessel revascularization. Keywords: anticoagulation, restenosis, thrombosis, bleeding, optical coherence tomography, titanium
Resumo:
For advanced devices in the application fields of data storage, solar cell and biosensing, one of the major challenges to achieve high efficiency is the fabrication of nanopatterned metal oxide surfaces. Such surfaces often require both precise structure at the nanometer scale and controllable patterned structure at the macro scale. Nowadays, the dominating candidates to fabricate nanopatterned surfaces are the lithographic technique and block-copolymer masks, most of which are unfortunately costly and inefficient. An alternative bottom-up approach, which involves organic/inorganic self-assembly and dip-coating deposition, has been studied intensively in recent years and has proven to be an effective technique for the fabrication of nanoperforated metal oxide thin films. The overall objective of this work was to optimize the synthesis conditions of nanoperforated TiO2 (NP-TiO2) thin films, especially to be compatible with mixed metal oxide systems. Another goal was to develop fabrication and processing of NP-TiO2 thin films towards largescale production and seek new applications for solar cells and biosensing. Besides the traditional dip-coating and drop-casting methods, inkjet printing was used to prepare thin films of metal oxides, with the advantage of depositing the ink onto target areas, further enabling cost-effective fabrication of micro-patterned nanoperforated metal oxide thin films. The films were characterized by water contact angle determination, Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and Grazing Incidence XRay Diffraction. In this study, well-ordered zinc titanate nanoperforated thin films with different Zn/Ti ratios were produced successfully with zinc precursor content up to 50 mol%, and the dominating phase was Zn2Ti3O8. NP-TiO2 structures were also obtained by a cost-efficient means, namely inkjet printing, at both ambient temperature and 60 °C. To further explore new biosensing applications of nanoperforated oxide thin films, inkjet printing was used for the fabrication of both continuous and patterned polymeric films onto NP-TiO2 and perfluorinated phosphate functionalized NP-TiO2 substrates, respectively. The NP-TiO2 films can be also functionalized with a fluoroalkylsilane, resulting in hydrophobic surfaces on both titania and silica. The surface energy contrast in the nanoperforations can be tuned by irradiating the films with UV light, which provides ideal model systems for wettability studies.