Buchenhofen wastewater treatment plant of Wupperverband (650,000 p.e.) is currently being expanded for targeted nitrogen elimination. In view of the limited space available for extension, an optimized control concept is to be used in order to minimize the number of additional tanks required. This concept was investigated by dynamic simulation based on Activated Sludge Model No. 1. The investigations included a pure feedback control configuration and a configuration combining feedback und feedforward control, considering the influent ammonium load, for aeration. The results show that combined feedforward/feedback control has significant advantages over pure feedback control. In particular, this configuration allows a reduction in the effluent NH4-N peaks, which is especially important because of the low NH4-N limit of 5 mg NH4-N/L in a grab sample.

The objective of this study is to investigate to what extent the nitrification capacity of a pilot-plant fixed-film reactor changes during extensive periods of nutrient supply deficiency. The examined pilot-plant was an upflow reactor filled with swelling clay of medium grain size (6 to 8 mm).The experiments revealed that the maximum nitrification rate remained practically constant during the first weeks after the onset of unregulated ammonium supply. The capacity declined slowly, dropping to approximately 66% of the initial capacity after about ten weeks. Still ammonium peaks of up to 8 mg/l were readily nitrified throughout the entire period of the experiment. The reduction in nitrification capacity during the observation period did not result from decay processes of biomass but from the reactor becoming blocked and thus hampering transfer processes. It could be observed that the detached organisms attached again further up.This semi-industrial project demonstrated that a plug-flow fixed-film reactor can be used as effective means of tertiary nitrification.

In order to study the significance of non-ECG-gated cardiac computed tomography (CCT) for the diagnosis of hypertrophic cardiomyopathies, the method was applied in 55 consecutive patients and the data were correlated with the echocardiogram. In a subset of 18 patients left and right heart catheterization was additionally performed, and in a subset of 17 patients, endomyocardial biopsy was performed. The CCT turned out to be an easily applicable, non-time-consuming method for obtaining a sectional visualization of the left and right ventricle. Regarding the septal thickness, there was an unexpectedly high correlation between CCT and echocardiogram (r = 0.9). The left ventricular deformity observed by echocardiogram and angiography in patients with hypertrophic cardiomyopathies corresponded well to that visualized by CCT, leading to a good differentiation between HOCM and HNCM (diagnostic specificity: 92% and 80%, respectively). It is concluded that the non-ECG-gated CCT seems to be a very helpful non-invasive method for diagnosing hypertrophic cardiomyopathies and differentiating between the obstructive and nonobstructive forms. From a clinical point of view, this may be important, mainly in patients in whom no clear-cut diagnosis is possible using previously applied non-invasive methods, including echocardiography. It may also be useful for follow-up studies, providing a sectional insight into the distribution of left ventricular hypertrophy.

In a total of 82 patients (age 37-71 years) with an occluded left anterior descending artery (LAD) the results of coronary revascularization were evaluated 7 months postoperatively on average. In all patients the indications for revascularization was given by clinical symptoms (angina pectoris) or by prognostic reasons. In patients with multivessel disease. In patients with anterior wall infarction viable myocardium was proven by thallium-scintigram at rest and during exercise. 29 patients were evaluated by coronary angiography postoperatively, in 19 patients the angiograms of the left ventricle could be assessed quantitatively. Total patency rate was 76%, for the LAD 69%, for the circumflex artery 73% and for the right coronary artery 83%. The relatively low patency rate for the LAD was caused by an increased collateral flow to the occluded LAD and therefore by a significantly lower bypass flowrate measured during surgery. Angina pectoris improved markedly, 55% of patients had angina pectoris class III or IV versus 10% postoperatively. These changes were observed in all patients irrespectively of patency rate or occluded grafts to the LAD. Left ventricular volumes and ejection fraction did not change on average after revascularization. Only end-diastolic volume increased significantly in patients with an occluded graft to the LAD. There was a tendency of the end-systolic volume to decrease postoperatively in patients with complete revascularization or at least an open graft to the LAD. The results show a similar clinical improvement in these patients with occluded LAD as shown after "usual" revascularization in other patients. Preoperative coronary angiograms are helpful in judging the postoperative outcome of grafts to the occluded LAD.

The effects of the antiarrhythmic drugs disopyramide (D), mexiletine (M), and propafenone (P) on left ventricular function after intravenous injection and after oral therapy of at least 48 hours, and of the combined oral application of D and M, were studied by M-mode echocardiography in patients with ventricular arrhythmias in whom antiarrhythmic therapy was indicated. The drugs were given in doses comparable in terms of clinical efficacy. The results showed that the three drugs had varying negative inotropic power. The intravenous injection resulted in a more pronounced cardiac depression than the oral therapy. The most significant decrease in left ventricular wall motion after intravenous and oral application was seen after D, the smallest negative inotropic effect after M. P caused a cardiac depression between these extremes. After the combined oral application of D and M the impairment of left ventricular function was more pronounced than after therapy with the single drugs.

12 patients with cardiac tumors (7 myxomas of the left, 2 of the right atrium, 2 ventricular, 2 intramural tumors and 1 epicardial cyst) were examined by M-Mode-(ME) and two-dimensional (2DE) echocardiography, computertomography (CT) and heart catheterization (HK) with angiography (A). The results were compared with intraoperative findings. There were no false negative results with 2DE and CT, but in 1 case the size of an intramural tumor was underestimated by 2DE. With ME all atrial myxomas were diagnosed, but 2 ventricular and 2 intramural tumors as well as the epicardial cyst were overlooked. Also with HK and A, the 2 intramural tumors and the epicardial cyst were not recognized well. The results indicate that the diagnosis of cardiac tumors can be made with great accuracy by noninvasive methods. The sensitivity of the single methods depends on the location of the tumors.

The activity of the selenoenzyme glutathione peroxidase (EC 1.11.1.9) was determined in platelets of 15 patients with acute myocardial infarction and 13 control subjects. The platelets of the patients had significantly lower activities of the enzyme (P(t)>0.99). This may be related to the pathogenesis of the disease.

A case of a 32 year-old male with a cardiac metastasis of a fibrosarcoma is reported. The patient suffered from chest pain, the ECG revealed deep negative T-waves in the precordial leads. A tumor in the apical region of the left ventricle was found by two dimensional echocardiography, whereas the diagnosis was not possible by the M-mode recording.