70 research outputs found
Flash sintering of injection molded zirconia under AC electric field for enhancement of optical properties
Zirconia is a very versatile ceramic material used in many applications, from structural components to healthcare implantable parts. The majority of current flash research has been performed using uniaxial pressed samples. In our research, we looked to study a large-scale manufacturing technique to produce the samples to be sintered. Ceramic injection molding (CIM) is a known method to produce complex shaped parts with great precision and high density. The high binder content in CIM parts can cause difficulty during flash sintering, due to the high porosity left after debinding process. This can cause localization and flashover during the application of the electric field. Commercially injection molded partially stabilized zirconia (3YSZ) was chosen as it has important properties, such high fracture toughness, however, it is usually opaque due to inherent microstructure defects and grain size of the material. For many applications, zirconia, does not require a particular color or specific appearance, but in some cases for aesthetic uses, a transparent-like material is highly desirable. This paper will describe the results on flash sintering equipment design and field parameters used in order to optimize levels of translucency in zirconia disks, with high fracture toughness. The flash sintering process is shown to be repeatable, and is compared with conventionally sintered samples to assess the improvement on translucency and/or fracture toughness. It is then proposed that flash sintering is an enabling mechanism for the use of zirconia in a wider range of applications and markets, where aesthetics and toughness are required in parallel
Investment Evaluation of a Suburban Coastal Transport System
This paper aims at determining the optimum viable solution of an investment on a suburban coastal shipping system in the area of Athens. More specifically the development of a sea transport system, alternative to the existing road one, that connects Piraeus with the southern suburban coastal area of Athens is examined. The best viable solution of such an undertaking is considered to be the one, which under the existing constraints maximises the total profit that derives from this investment. The variables used for the formation of the constraints are the number of vessels used, the routing and the price of the services. The article focuses on the financing alternatives of the project and their impact on its economic efficiency and concludes with the best viable scenarios and optimum solution
Differential trends in the rising incidence of endometrial cancer by type: data from a UK population-based registry from 1994 to 2006
BACKGROUND: Endometrial cancer is the most common gynaecological cancer in the western world, the incidence increasing in the United Kingdom by over 40 % since 1993. Two types of endometrial cancer exist – oestrogen-dependent type 1 with good prognosis and non-oestrogen-dependent type 2 with poor prognosis. The histopathological distribution of the increase in endometrial cancer is unknown. This study investigates the observed incidence trends of the two types, the age, stage, and socioeconomic distribution of this increase and survival outcome. METHODS: Data were analysed from 6867 women with endometrial cancer registered between 1994 and 2006, at a UK population-based cancer registry. RESULTS: Increased endometrial cancer incidence is confined to type 1 cancers with a significant increase in age standardised incidenc
A labelled discrete choice experiment adds realism to the choices presented: preferences for surveillance tests for Barrett esophagus
<p>Abstract</p> <p>Background</p> <p>Discrete choice experiments (DCEs) allow systematic assessment of preferences by asking respondents to choose between scenarios. We conducted a labelled discrete choice experiment with realistic choices to investigate patients' trade-offs between the expected health gains and the burden of testing in surveillance of Barrett esophagus (BE).</p> <p>Methods</p> <p>Fifteen choice scenarios were selected based on 2 attributes: 1) type of test (endoscopy and two less burdensome fictitious tests), 2) frequency of surveillance. Each test-frequency combination was associated with its own realistic decrease in risk of dying from esophageal adenocarcinoma. A conditional logit model was fitted.</p> <p>Results</p> <p>Of 297 eligible patients (155 BE and 142 with non-specific upper GI symptoms), 247 completed the questionnaire (84%). Patients preferred surveillance to no surveillance. Current surveillance schemes of once every 1–2 years were amongst the most preferred alternatives. Higher health gains were preferred over those with lower health gains, except when test frequencies exceeded once a year. For similar health gains, patients preferred video-capsule over saliva swab and least preferred endoscopy.</p> <p>Conclusion</p> <p>This first example of a labelled DCE using realistic scenarios in a healthcare context shows that such experiments are feasible. A comparison of labelled and unlabelled designs taking into account setting and research question is recommended.</p
Global political responsibility for the conservation of albatrosses and large petrels
Migratory marine species cross political borders and enter the high seas, where the lack of an effective global management framework for biodiversity leaves them vulnerable to threats. Here, we combine 10,108 tracks from 5775 individual birds at 87 sites with data on breeding population sizes to estimate the relative year-round importance of national jurisdictions and high seas areas for 39 species of albatrosses and large petrels. Populations from every country made extensive use of the high seas, indicating the stake each country has in the management of biodiversity in international waters. We quantified the links among national populations of these threatened seabirds and the regional fisheries management organizations (RFMOs) which regulate fishing in the high seas. This work makes explicit the relative responsibilities that each country and RFMO has for the management of shared biodiversity, providing invaluable information for the conservation and management of migratory species in the marine realm
Patients' and urologists' preferences for prostate cancer treatment: A discrete choice experiment
__Abstract__
Background: Patients' preferences are important for shared decision making. Therefore, we investigated patients' and urologists' preferences for treatment alternatives for early prostate cancer (PC). Methods: A discrete choice experiment was conducted among 150 patients who were waiting for their biopsy results, and 150 urologists. Regression analysis was used to determine patients' and urologists' stated preferences using scenarios based on PC treatment modality (radiotherapy, surgery, and active surveillance (AS)), and risks of urinary incontinence and erectile dysfunction.Results:The response rate was 110 out of 150 (73%) for patients and 50 out of 150 (33%) for urologists. Risk of urinary incontinence was an important determinant of both patients' and urologists' stated preferences for PC treatment (P<0.05). Treatment modality also influenced patients' stated preferences (P<0.05), whereas the risk of erectile dysfunction due to radiotherapy was mainly important to urologists (P<0.05). Both patients and urologists preferred AS to radical treatment, with the exception of patients with anxious/depressed feelings who preferred radical treatment to AS. Conclusion: Although patients and urologists generally may prefer similar treatments for PC, they showed different trade-offs between various specific treatment aspects. This implies that urologists need to be aware of potential differences compared with the patient's perspective on treatment decisions in shared decision making on PC treatment
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and nonbreeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging speciespublishedVersio
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