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The applicability of multivariable linear regression (MLR) models to estimate the maximum temperature inside a SOFC stack is investigated experimentally. The experiments were carried out with a complete 10 kW SOFC system. The behavior of the maximum temperature measured inside a SOFC stack with respect to four independent input variables (stack current, air flow, air inlet temperature and fuel flow) is examined following the design of experiments methodology, and MLR models are created based on the retrieved data. The practical feasibility of the MLR estimate is investigated experimentally with the 10 kW system by evaluating the accuracy of the estimate in two test cases: (i) a system load change where the stack temperature is regulated by a closed-loop controller using the MLR estimate and (ii) during operator-imposed disturbances in the fuel system (a variation in the methane conversion in the fuel pre-reformer). Finally, the performance of the MLR estimate is evaluated with another, 64-cell stack operated at higher current density. [ABSTRACT FROM AUTHOR]

A solid oxide fuel cell (SOFC) stack can exhibit both anodic and cathodic leakages, i.e. a fuel leak from the anode side and an air leak from the cathode side of the stack, respectively. This study describes the results of an in-situ leakage analysis conducted for a planar SOFC stack during 2000 hours of operation in an actual system environment. The leakages are quantified experimentally at nominal system operating conditions by conducting composition analysis and flow metering of gases for both fuel and air subsystems. Based on the calculated atomic hydrogen-to-carbon ratio of the fuel and air gases, it is found that the fuel leakages are mostly selective by nature: the leaking fuel gas does not have the same composition as the fuel system gas. A simple diffusive leakage model, based on the leakage being driven by concentration differences weighted by diffusion coefficients, is applied to quantify the amount of leakages. The leakage model provides a good correspondence with the experimental results of the gas analysis. [ABSTRACT FROM AUTHOR]

A 500 W SOFC stack provided by Topsoe Fuel Cells A/S was run with reformed diesel fuel for 1,200 h. Diesel fuel used was Swedish Environmental Class 1 containing <10 ppm of sulfur. The fuel was reformed with an autothermal reformer (ATR). The reformer consisted of a mixing chamber and a reactor chamber containing a noble metal catalyst provided by SüdChemie. The reformer used the diesel fuel without any pre-treatment such as sulfur adsorbent. The reformer unit was able to achieve high conversion of reactants with only ppm levels of higher hydrocarbons at the reformer outlet. Particulate emissions of the reformer were measured to be 30 μg m-3, a very low value even below daily exposure limits in ambient air set by the European Comission directives. The stack was first run with 3% humidified H2 + N2 fuel to obtain baseline performance and then switched to reformate. Diesel reformate was found not to induce significantly more long-term degradation on the stack compared to hydrogen case. However, an initial degradation of about 20 mV cell-1 was observed during the first 150 h on diesel fuel reformate. This could be an indication of a poisoning mechanism taking place, but needs further research to be verified. [ABSTRACT FROM AUTHOR]

The effect of anode off-gas recycling (AOGR) on the characteristic performance of a natural gas reformer equipped with a precious metal catalyst is investigated experimentally. The reformer is operated both with synthetic AOGR gas and in steam reforming (SR) conditions. The characteristic performance in SR and AOGR mode are compared with equilibrium, and it is found that equilibrium is more readily achieved in AOGR mode. The reformer is used for extended periods of time (100-1,000 h) in conditions where carbon formation is thermodynamically possible to measure any changes in characteristic performance. No significant change in the performance is observed due to carbon formation or catalyst deactivation. The reformer could be successfully implemented in a 10 kW SOFC system with an anode off-gas recycling loop. [ABSTRACT FROM AUTHOR]

There is an increasing demand for the results of cardiac markers (troponin I or T, creatine kinase MB mass and myoglobin) to be made available promptly after sample-taking. In order to shorten the turnaround time, the possibility of using EDTA- or heparin-plasma instead of serum was investigated. The study population comprised 391 patients with acute chest pain. Four different instruments and systems routinely used in Finland giving quantitative results were studied for the assays of creatine kinase isoenzyme MB mass, myoglobin, and troponin I or troponin T. In addition to serum samples, heparin-plasma seems to be useful for all three assays using the Access and Immulite systems, while EDTA-plasma seems to be useful for all three assays with the Access and Elecsys systems. For the AxSYM assays, serum samples seem to be the best alternative. In conclusion, it is possible to use a single EDTA- or heparin-plasma sample for Access, Elecsys and Immulite analysers, and thereby to shorten the turnaround time. In this way the quantitative analyses from plasma can be performed 30 min after taking the sample. [ABSTRACT FROM AUTHOR]

There is an increasing demand for the results of cardiac markers (troponin I or T, creatine kinase MB mass and myoglobin) to be made available promptly after sample-taking. In order to shorten the turnaround time, the possibility of using EDTA- or heparin-plasma instead of serum was investigated. The study population comprised 391 patients with acute chest pain. Four different instruments and systems routinely used in Finland giving quantitative results were studied for the assays of creatine kinase isoenzyme MB mass, myoglobin, and troponin I or troponin T. In addition to serum samples, heparin-plasma seems to be useful for all three assays using the Access and Immulite systems, while EDTA-plasma seems to be useful for all three assays with the Access and Elecsys systems. For the AxSYM assays, serum samples seem to be the best alternative. In conclusion, it is possible to use a single EDTA- or heparin-plasma sample for Access, Elecsys and Immulite analysers, and thereby to shorten the turnaround time. In this way the quantitative analyses from plasma can be performed 30 min after taking the sample. [ABSTRACT FROM AUTHOR]

Objective: To investigate the time window for ruling out myocardial infarction (MI) with troponin T (TnT) and creatine kinase isoenzyme MB mass (CK-MBm) and the prognosis of patients with ruled-out MI diagnosis.Design: The study was based on 397 patients admitted with a suspected acute coronary syndrome but with relief of symptoms within 24 h.Results: MI diagnosis was confirmed with elevated TnT (>0.10 microg/l) in 108 patients. in 91% within 12-24 h from the onset of symptoms, and in 99% within 12 h from admission. In 94 of these patients CK-MBm became elevated (>5.0 microg/l). in 95% within 10-12 h from the onset of symptoms, and in 99% within 6 h from admission. Among patients with ruled-out MI diagnosis, the 1-year incidence of recurrent coronary events was 29% in those with positive history of coronary heart disease (CHD) but only 7% in those without prior CHD (p < 0.001).Conclusion: Using TnT or CK-MBm, MI can be ruled out within 12 h from admission in the majority of patients. Among patients with ruled-out MI diagnosis, positive history of CHD is an important determinant of prognosis. [ABSTRACT FROM AUTHOR]

Context: Results from recent studies on the effects of beta1-blockade in patients with heart failure demonstrated a 34% reduction in total mortality. However, the effect of beta1-blockade on the frequency of hospitalizations, symptoms, and quality of life in patients with heart failure has not been fully explored.Objective: To examine the effects of the beta1-blocker controlled-release/extended-release metoprolol succinate (metoprolol CR/XL) on mortality, hospitalization, symptoms, and quality of life in patients with heart failure.Design: Randomized, double-blind controlled trial, preceded by a 2-week single-blind placebo run-in period, conducted from February 14, 1997, to October 31, 1998, with a mean follow-up of 1 year.Setting: Three hundred thirteen sites in 14 countries.Participants: Patients (n = 3991) with chronic heart failure, New York Heart Association (NYHA) functional class II to IV, and ejection fraction of 0.40 or less who were stabilized with optimum standard therapy.Interventions: Patients were randomized to metoprolol CR/XL, 25 mg once per day (NYHA class II), or 12.5 mg once per day (NYHA class III or IV), titrated for 6 to 8 weeks up to a target dosage of 200 mg once per day (n = 1990); or matching placebo (n = 2001).Main Outcome Measures: Total mortality or any hospitalization (time to first event), number of hospitalizations for worsening heart failure, and change in NYHA class, by intervention group; quality of life was assessed in a substudy of 741 patients.Results: The incidence of all predefined end points was lower in the metoprolol CR/XL group than in the placebo group, including total mortality or all-cause hospitalizations (the prespecified second primary end point; 641 vs 767 events; risk reduction, 19%; 95% confidence interval [CI], 10%-27%; P<.001); total mortality or hospitalizations due to worsening heart failure (311 vs 439 events; risk reduction, 31%; 95% CI, 20%-40%; P<.001), number of hospitalizations due to worsening heart failure (317 vs 451; P<.001); and number of days in hospital due to worsening heart failure (3401 vs 5303 days; P<.001). NYHA functional class, assessed by physicians, and McMaster Overall Treatment Evaluation score, assessed by patients, both improved in the metoprolol CR/XL group compared with the placebo group (P = .003 and P = .009, respectively).Conclusions: In this study of patients with symptomatic heartfailure, metoprolol CR/XL improved survival, reduced the need for hospitalizations due to worsening heart failure, improved NYHA functional class, and had beneficial effects on patient well-being. [ABSTRACT FROM AUTHOR]

Objective To determine lengths and causes of pre- and in-hospital delays in thrombolytic treatment.Design A prospective national survey covering 48 of the 51 Finnish university, central and general hospitals to obtain basic data before the start of a public campaign to shorten patient-related delay in acute myocardial infarction.Subjects One thousand and twelve consecutive patients with acute myocardial infarction who received thrombolytic therapy over 3 months in 1995 and who represent 40% of all patients with confirmed acute myocardial infarction.Results The median interval between onset of infarction symptoms and initiation of thrombolytic therapy was 160 min (30–647). Only 13% of the patients received thrombolysis within 60 min and 38% within 120 min. The median time from the onset of symptoms to the call for help was 60 min (5–491), and no difference was found in patients with or without a history of previous myocardial infarction (60 and 64 min, respectively). Only 52% of the patients called to the dispatch centre. The median delay from calling for help to hospital arrival was 40 min (10–170). The median in-hospital door-to-needle thrombolysis delay was 40 min (12–196). In 13% of hospitals the median delay was more than 60 min. The emergency physician encountered difficulties in decision making in 33% of cases.Conclusions Only 38% of the patients received thrombolysis within 2 h of onset of symptoms. Patient-related delay before they sought help accounted for the major portion of the total treatment delay. Thus the findings emphasize the importance of prompt action when people are confronted with an acute heart attack. Reorganizing the emergency medical service and emergency department routines is also a necessary target to shorten thrombolysis delays. The delay attributable to transporting patients could be shortened by initiating thrombolytic treatment in the pre-hospital setting. In Finnish hospitals, door-toneedle delay was acceptable in cases with clear indications for thrombolysis. However, emergency physicians often had diagnostic difficulties, which led to remarkably longer in-hospital delays. [ABSTRACT FROM PUBLISHER]

We investigated the incidence of fatal traffic accidents caused by sudden incapacity of the driver due to cardiac and other illnesses. The retrospective analysis was gleaned from Finnish traffic accident data files from 1984-1989, and police records of traffic accidents, from Canton de Vaud, Switzerland from 1986-1989. The annual rates of all traffic fatalities per million inhabitants were 125 in Finland and 212 in Vaud. Sudden driver incapacity due to acute illness caused 1.8 and 7.3 automobile driver deaths annually per million inhabitants in Finland and in Vaud, respectively. The corresponding rates for all-cause traffic deaths were 326 and 423, for driver deaths 105 and 167, and for those due to driver incapacity 4.7 and 15.6. Sudden driver incapacity caused 1. 5% of all traffic deaths in Finland, and 3. 4% in Vaud. Probable cardiac arrest caused 2. 1% of all drivers‘ deaths in Finland and 1. 7% in Vaud, respectively. Deaths caused by professional drivers’ sudden incapacity were responsible for 0. 11% of all traffic deaths in Finland, and for 0% in Vaud. Old age and short mileage were associated with illness-caused accidents. Accidents caused by sudden incapacity of the driver are rare causes of traffic deaths and hard to foresee. While this report relates to all drivers, we suggest there should be individual risk stratification for professional drivers with heart disease. However, non-professional drivers who are elderly and who have symptomatic cardiac disease should limit their driving to short distances and at low speed. [ABSTRACT FROM PUBLISHER]

The antiarrhythmic efficacy of mexiletine in acute myocardial infarction (AMI) was studied in 99 patients randomized to mexiletine or placebo treatment. The loading dose was 250 mg i.v. and 400 mg orally followed by 200 mg orally 2 h later, and thereafter 200 mg t.i.d. up to 42 h. Arrhythmias occurring during 48 h were analysed from continuous electrocardiographic recordings. AMI was verified in 35 of 50 mexiletine patients and in 38 of 49 placebo patients. No deaths or instances of ventricular fibrillation occurred in the AMI patients. The number of patients who had any event of accelerated idioventricular rhythm (AIVR; <0.05), runs of ventricular premature beats (VPBs; <0.01), ventricular tachycardia (<0.01) and Ron T beats (<0.05) was smaller in the mexiletine group than in the placebo group. The number of all VPBs (<0.05), hours with occurrence of AIVR (<0.05), runs (<0.01) and Ron T beats (<0.05) was smaller in the mexiletine than in the placebo group. Serum levels of mexiletine tended to be low throughout the study. The half-life of the elimination was 13.7±7.2 h (means±S.D.). Adverse effects were infrequent, and the treatment was well-tolerated. Combined iv. and oral mexiletine prophylaxis significantly suppressed repetitive ventricular tachyarrhythmias and RonT beats. However, no clinical benefit from mexiletine treatment could be shown in a coronary care unit with a low frequency of primary ventricular fibrillation. [ABSTRACT FROM PUBLISHER]

Myopericarditis is a rare extraintestinal complication of inflammatory bowel disease (IBD). It has also been described as a side-effect of the treatment of IBD. We report a 37-year-old-woman with Crohn's disease who had several mild episodes of myopericarditis, two of which were associated with a pleural effusion, and two with conduction abnormalities in the atrioventricular node. During the last episode, a nodal rhythm was followed by a third-degree atrioventricular block and a prolonged pause, resulting in loss of consciousness and convulsions. A permanent pacemaker was implanted. Our patient is also human lymphocyte antigen (HLA) B27-positive. HLA B27 is known to be associated with conduction disturbances in the AV node. Recurrent myopericarditis can be a sign of IBD. [ABSTRACT FROM AUTHOR]

We investigated the difference in the number of myocardial infarction (MI) diagnoses based on troponin T compared with clinical and epidemiologic (modified FINnish Multinational MONItoring of trends and determinants in CArdiovascular diseases) diagnoses, and the prognosis of patients with discordant diagnoses. Five hundred fifty-nine consecutive patients (315 men and 244 women, median age 69 years) were admitted to the hospital with a suspected acute coronary syndrome. Median follow-up time was 17 months. Of the 559 patients, 127 had a clinical and 137 an epidemiologic diagnosis of MI. When a diagnosis of MI was primarily based on troponin T (>0.10 microg/L), the number of MIs was 169, which increased by 33% compared with the number of MIs by clinical diagnosis, and by 23% compared with those by epidemiologic diagnosis. However, troponin T was not elevated in 13% of the 127 patients with the clinical diagnosis and in 14% of the 137 patients with the epidemiologic diagnosis of MI. Among patients in whom clinical diagnosis of MI was not made, the prognosis with regard to coronary death or nonfatal MI was not significantly worse in patients with troponin T >0.10 microg/L than < or =0.10 microg/L (hazard ratio 1.07; 95% confidence interval 0.62 to 1.84). In patients with a suspected acute coronary syndrome, troponin T-based diagnostics leads to an increase in the number of patients diagnosed with MI compared with clinical or epidemiologic diagnosis. The prognostic impact of troponin T in patients without clinical diagnosis of MI based on elevations in conventional enzyme activities needs further study in larger series of patients. [ABSTRACT FROM AUTHOR]