644 resultados para corrosion prevention
Resumo:
Data from studies in the United States suggest that young people engaging in health-compromising behaviors have lower access to health care. Using data from a Swiss national survey we tested the hypothesis that in a country with universal insurance coverage, adolescents engaging in health-compromising behaviors access primary care to the same extent as those who do not engage in these behaviors.
Resumo:
Even though patients who develop ischemic stroke despite taking antiplatelet drugs represent a considerable proportion of stroke hospital admissions, there is a paucity of data from investigational studies regarding the most suitable therapeutic intervention. There have been no clinical trials to test whether increasing the dose or switching antiplatelet agents reduces the risk for subsequent events. Certain issues have to be considered in patients managed for a first or recurrent stroke while receiving antiplatelet agents. Therapeutic failure may be due to either poor adherence to treatment, associated co-morbid conditions and diminished antiplatelet effects (resistance to treatment). A diagnostic work up is warranted to identify the etiology and underlying mechanism of stroke, thereby guiding further management. Risk factors (including hypertension, dyslipidemia and diabetes) should be treated according to current guidelines. Aspirin or aspirin plus clopidogrel may be used in the acute and early phase of ischemic stroke, whereas in the long-term, antiplatelet treatment should be continued with aspirin, aspirin/extended release dipyridamole or clopidogrel monotherapy taking into account tolerance, safety, adherence and cost issues. Secondary measures to educate patients about stroke, the importance of adherence to medication, behavioral modification relating to tobacco use, physical activity, alcohol consumption and diet to control excess weight should also be implemented.
Resumo:
Complications related to the neck-stem junction of modular stems used for total hip arthroplasty (THA) are generating increasing concern. A 74-year-old male had increasing pain and a cutaneous reaction around the scar 1 year after THA with a modular neck-stem. Imaging revealed osteolysis of the calcar and a pseudo-tumour adjacent to the neck-stem junction. Serum cobalt levels were elevated. Revision surgery to exchange the stem and liner and to resect the pseudo-tumour was performed. Analysis of the stem by scanning electron microscopy and by energy dispersive X-ray and white light interferometry showed fretting corrosion at the neck-stem junction contrasting with minimal changes at the head-neck junction. Thus, despite dry assembly of the neck and stem on the back table at primary THA, full neck-stem contact was not achieved, and the resulting micromotion at the interface led to fretting corrosion. This case highlights the mechanism of fretting corrosion at the neck-stem interface responsible for adverse local tissue reactions. Clinical and radiological follow-up is mandatory in patients with dual-modular stems.
Resumo:
Objective information for the groups exposed to the disease and the public in general is the only step that is currently possible in the prevention of AIDS. A certain number of information and support actions have been developed as a consequence of the appearance of AIDS in Switzerland. The AIDS information hot-line at the CHUV is one of these actions with the aim of orienting the information according to demand and examining the utility of this means, we made a prospective evaluation of the calls (between 23 October 1985-inception of the line and 31 March 1986). Out of a total of 535 calls, 317 requests for appointments (tests, consultation) or written documentation, and 218 (41%) were transferred to the doctor; 39% of the calls came from people who were directly concerned (ill, with a positive test, exposed groups), 11% from health professionals, and 47% from the general public. 56% of the calls were concerned with transmission of the disease (sexual, blood, indirect), 22% with the meaning of the detection test, 22% referred to the symptoms of the disease. According to the doctor's estimate, although the standard of knowledge is satisfactory in 55% of the cases, a considerable number of false ideas, that generate irrational fear, still persist. This hot-line thus provides a sympathetic ear and individual support, particularly for the exposed groups, rather than information about the disease. The existence of this action, therefore, appears justified, but must be integrated into a global strategy of information promotion.
Resumo:
In this thesis fouling of conventional filter fabrics and membranes was studied. In the beginning of the thesis fouling and how it can be measured and predicted is reviewed. Information on different methods on how fouling canbe decreased or cleaned away is also given. The experimental part is divided into two sections; fabric filtration and membrane filtration. Fouling of the filter fabrics was studied with silica or cupper slurries and fouling of the membranes was studied with pulp and paper mill waters. The fouled filter materials were characterised according to many different methods. The most useful way to observe fouling is to measure the changes in the permeate flux. Fouling can also be seen visually e.g. with scanning electron microscopy. Consequently, also the reason for the fouling in question might be found. Different filtration characteristics affect fouling e.g. as the filtration pressure was increased it did not have much influence on the permeate flux, but the pressure caused the membrane to get fouled faster. Also, an increase of shear rate on the membrane surface decreased fouling. Different pretreatment methods for the effluent were tested in membrane filtration to decrease fouling. The tested methods; biological treatment, ozonation, enzymatic treatment and flocculation, did not have a clear influence on the fouling of the membrane, but e.g. a biological treatment combined with ultrafiltration made the tested groundwood mill circulation water purer than ultrafiltration alone.
Resumo:
Superheater corrosion causes vast annual losses for the power companies. With a reliable corrosion prediction method, the plants can be designed accordingly, and knowledge of fuel selection and determination of process conditions may be utilized to minimize superheater corrosion. Growing interest to use recycled fuels creates additional demands for the prediction of corrosion potential. Models depending on corrosion theories will fail, if relations between the inputs and the output are poorly known. A prediction model based on fuzzy logic and an artificial neural network is able to improve its performance as the amount of data increases. The corrosion rate of a superheater material can most reliably be detected with a test done in a test combustor or in a commercial boiler. The steel samples can be located in a special, temperature-controlled probe, and exposed to the corrosive environment for a desired time. These tests give information about the average corrosion potential in that environment. Samples may also be cut from superheaters during shutdowns. The analysis ofsamples taken from probes or superheaters after exposure to corrosive environment is a demanding task: if the corrosive contaminants can be reliably analyzed, the corrosion chemistry can be determined, and an estimate of the material lifetime can be given. In cases where the reason for corrosion is not clear, the determination of the corrosion chemistry and the lifetime estimation is more demanding. In order to provide a laboratory tool for the analysis and prediction, a newapproach was chosen. During this study, the following tools were generated: · Amodel for the prediction of superheater fireside corrosion, based on fuzzy logic and an artificial neural network, build upon a corrosion database developed offuel and bed material analyses, and measured corrosion data. The developed model predicts superheater corrosion with high accuracy at the early stages of a project. · An adaptive corrosion analysis tool based on image analysis, constructedas an expert system. This system utilizes implementation of user-defined algorithms, which allows the development of an artificially intelligent system for thetask. According to the results of the analyses, several new rules were developed for the determination of the degree and type of corrosion. By combining these two tools, a user-friendly expert system for the prediction and analyses of superheater fireside corrosion was developed. This tool may also be used for the minimization of corrosion risks by the design of fluidized bed boilers.
Resumo:
The article proposes an alternative approach to policies for preventing doping in cycling, based on in-depth analysis of the functioning of nine of the 40 world professional teams and the careers of the 2,351 riders who were or have been professionals since 2005. The first part shows that the instruments of prevention have been based on a questionable understanding of doping as an individual moral fault, and have not produced the expected results. The second part proposes to analyse the ways in which teams and riders produce their achievments, so as to put forward an alternative to the anti-doping policies used hitherto, which have little impact on riders. The study shows that it is more pertinent to examine the forms of employment and the business models, because these have important effects on cycling professionals' conditions of work. It makes it possible to identify three dimensions of the risk of doping on which organisations can act in their antidoping policies: team organisation, riders' preparation and workload, and the precarity of employment.
Resumo:
Fallvignette: Ein 58-jähriger Mann hatte vor einem Jahr einen Herzinfarkt, der mit einem beschichteten Stent versorgt wurde. Im Beruf hat er eine verantwortungsvolle Position und ist häufig geschäftlich unterwegs. Er gibt an, dass er Mühe mit der Einnahme seiner fünf Medikamente (Statin, β-Blocker, ACE-Hemmer, Clopidogrel, Acetylsalizylsäure) hat und dass er ab und zu vergisst, eines zu nehmen. Frage: Könnte ihm ein Kombinationspräparat (Polypille) helfen, seine Medikamente regelmässig einzunehmen? Hintergrund: Weltweit sind Herz-Kreislauf-Erkrankungen die führende Ursache für Tod und Behinderung. Um diese Krankheitslast zu vermindern, ist eine bevölkerungsbezogene Prävention entscheidend, bei der bekannte kardiovaskuläre Risikofaktoren kontrolliert werden. Das Konzept der Polypille mit einer fixen Kombination von mindestens einem Antihypertensivum und einem Statin wurde vor allem in Hinblick auf Entwicklungs- und Schwellenländer entwickelt. Die Primärprävention ist in diesen Ländern schwierig durch führbar; eine einzige Tablette wäre dort eine kostengünstige Variante. Aber auch in reichen Ländern könnte die Polypille sinnvoll sein, um z.B. die Compliance bei multimorbiden Patienten zu verbessern. Als Polypille werden verschiedene Kombinationen von Medikamenten angeboten, ihre Wirksamkeit und möglichen Nebenwirkungen sind jedoch unklar. Ziel dieses Reviews war, ihre Wirksamkeit in der primären und sekundären Prävention bezüglich Mortalität, nicht-tödliche kardiovaskuläre Ereignisse und Blutdruck-bzw. Lipidsenkung zu überprüfen.
Resumo:
BACKGROUND: The considerable malaria decline in several countries challenges the strategy of chemoprophylaxis for travellers visiting moderate- to low-risk areas. An international consensus on the best strategy is lacking. It is essential to include travellers' opinions in the decision process. The preference of travellers regarding malaria prevention for moderate- to low-risk areas, related to their risk perception, as well as the reasons for their choices were investigated. METHODS: Prior to pre-travel consultation in the Travel Clinic, a self-administered questionnaire was given to travellers visiting moderate- to low-risk malaria areas. Four preventive options were proposed to the traveller, i.e., bite prevention only, chemoprophylaxis, stand-by emergency treatment alone, and stand-by emergency treatment with rapid diagnostic test. The information was accompanied by a risk scale for incidence of malaria, anti-malarial adverse drug reactions and other travel-related risks, inspired by Paling palettes from the Risk Communication Institute. RESULTS: A total of 391 travellers were included from December 2012 to December 2013. Fifty-nine (15%) opted for chemoprophylaxis, 116 (30%) for stand-by emergency treatment, 112 (29%) for stand-by emergency treatment with rapid diagnostic test, 100 (26%) for bite prevention only, and four (1%) for other choices. Travellers choosing chemoprophylaxis justified their choice for security reasons (42%), better preventive action (29%), higher efficacy (15%) and easiness (15%). The reasons for choosing stand-by treatment or bite prevention only were less medication consumed (29%), less adverse drug reactions (23%) and lower price (9%). Those who chose chemoprophylaxis were more likely to have used it in the past (OR = 3.0 (CI 1.7-5.44)), but were not different in terms of demographic, travel characteristics or risk behaviour. CONCLUSIONS: When travelling to moderate- to low-risk malaria areas, 85% of interviewees chose not to take chemoprophylaxis as malaria prevention, although most guidelines recommend it. They had coherent reasons for their choice. New recommendations should include shared decision-making to take into account travellers' preferences.
Resumo:
Parastomal hernia (PSH) is the most frequent long-term stoma complication with serious negative effects on quality of life. Surgical revision is often required and has a substantial morbidity and recurrence rate. The development of PSH requires revisional surgery with a substantial perioperative morbidity and high failure rate in the long-term follow-up. Prophylactic parastomal mesh insertion during stoma creation has the potential to reduce the rate of PSH, but carries the risk of early and late mesh-related complications such as infection, fibrosis, mesh shrinkage, and/or bowel erosion. We developed a new stomaplasty ring (KORING), which is easy to implant, avoids potential mesh-related complications, and has a high potential of long-term prevention of PSH. Here we describe the technique and the first use.
Resumo:
The present study was initiated with the aim to assess the in vivo electrochemical corrosion behaviour of CoCrMo biomedical alloys in human synovial fluids in an attempt to identify possible patient or pathology specific effects. For this, electrochemical measurements (open circuit potential OCP, polarization resistance Rp, potentiodynamic polarization curves, electrochemical impedance spectroscopy EIS) were carried out on fluids extracted from patients with different articular pathologies and prosthesis revisions. Those electrochemical measurements could be carried out with outstanding precision and signal stability. The results show that the corrosion behaviour of CoCrMo alloy in synovial fluids not only depends on material reactivity but also on the specific reactions of synovial fluid components, most likely involving reactive oxygen species. In some patients the latter were found to determine the whole cathodic and anodic electrochemical response. Depending on patients, corrosion rates varied significantly between 50 and 750mgdm(-2)year(-1).