Biomedical subjects

M Kühni

Publications and source records attributed to M Kühni.

15 recordsLinked to original sources

PubMed2002

The EAWAG Bio-P module for activated sludge model No. 3.

An additional module for the prediction of enhanced biological phosphorus removal is presented on the basis of a calibrated version of ASM3. The module uses modified processes from ASM2d but neglects the fermentation of readily degradable substrate. Biomass decay is modeled in the form of endogenous respiration as in ASM3. The glycogen pool and biologically induced P-precipitation is not taken into account. The module was systematically calibrated with experimental data from various batch experiments, a full-scale WWTP and a pilot plant treating Swiss municipal wastewater. A standard parameter set allowed all data to be simulated.

Calibration↗

PubMed2001

Calibration and validation of an ASM3-based steady-state model for activated sludge systems--part I: Prediction of nitrogen removal and sludge production.

The steady-state model from Siegrist and Gujer (1994) which can be used for the design and optimisation of nitrogen-removing activated sludge plants is applied to the stoichiometrics and kinetics of a validated Activated Sludge Model No. 3. It considers the wastewater composition, the effect of the electron acceptor on the average sludge production, the oxygen input into anoxic volumes, denitrification in the secondary clarifier, the temperature and various operating conditions. The organic substrate for denitrification originates from readily degradable substrate from the influent, from the hydrolysis of slowly degradable particulate substrate along the activated sludge plant and from the endogenous respiration of the biomass. The model is calibrated and validated with data from long-term full-scale and pilot-plant experiments for Swiss municipal wastewater. The most sensitive parameters as well as the uncertainty of the model prognosis for various COD-to-nitrogen ratios from inlet water and anoxic volume fractions were calculated with the aid of sensitivity analyses and Monte-Carlo simulations. Excel spreadsheets of the model for different flow schemes are available from the corresponding author.

Biomass↗

PubMed2001

Calibration and validation of an ASM3-based steady-state model for activated sludge systems--part II: Prediction of phosphorus removal.

An ASM3-based steady-state model which can be used for estimating the average nitrogen-removal, sludge-production and phosphorus-removal rates of different biological phosphorus-removing systems (AAO, UCT, intermittent processes) is developed. It considers the wastewater composition, the oxygen and nitrate input in the anaerobic compartment and the interaction between biological phosphorus removal and denitrification for different operating conditions. The model is calibrated and validated with data from a number of long-term pilot and full-scale experiments for Swiss municipal wastewater. The steady-state model is adequate for a comparison of different BPR process configurations or for a first estimation of the nutrient-removal efficiency. It allows the plant performance and key parameters to be determined very quickly. Excel spreadsheets of the model for different flow schemes are available from the corresponding author.

Anaerobiosis↗

PubMed2001

The EAWAG Bio-P module for activated sludge model No. 3.

An additional module for the prediction of enhanced biological phosphorus removal is presented on the basis of a calibrated version of ASM3. The module uses modified processes from ASM2d but neglects the fermentation of readily degradable substrate. Biomass decay is modeled in the form of endogenous respiration as in ASM3. Moreover, an additional glycogen pool and biologically induced P-precipitation were not taken into account. The module was systematically calibrated with experimental data from various batch experiments, a full-scale WWTP and a pilot plant treating Swiss municipal waste water. A standard parameter set allowed all data to be simulated.

Biomass↗

PubMed1994

Growth and regulation of enzyme synthesis in the nitrilotriacetic acid (NTA)-degrading bacterium Chelatobacter heintzii ATCC 29600.

In the aerobic bacterium Chelatobacter heintzii, growth and regulation of enzymes involved in nitrilotriacetic acid (NTA) degradation have been investigated in chemostat culture during cultivation with glucose, NTA or mixtures thereof. In batch culture mu max with NTA was 0.18 h-1 and with glucose 0.22 h-1. Growth yields for both substrates were reduced at low dilution rates. During growth with NTA specific activity of the NTA monooxygenase (NTA-MO) exhibited a maximum at D = 0.03 h-1 and gradually decreased with increasing dilution rates. In glucose-grown cells the specific activity as well as immunologically detectable NTA-MO protein was always close to the detection limit. During cultivation with different mixtures of NTA and glucose at a dilution rate of 0.06 h-1, both substrates were utilized simultaneously, irrespective of the NTA/glucose ratio and the presence of excess ammonia. Synthesis of both NTA-MO and iminodiacetic acid dehydrogenase became induced when NTA contributed to more than approximately 1-3% of the total carbon in the substrate mixture supplied. However, NTA was also degraded when the proportion of NTA in the mixture was lower than 1%, which is consistent with the low constitutive level of expression for NTA-MO observed. Results are discussed with respect to NTA biodegradation during sewage treatment and in ecosystems.

Bacterial Proteins↗

PubMed1987

[Diagnosis of glomerular and non-glomerular erythrocyturia using phase contrast microscopy of the urine sediment].

Recently the appearance of deformed polymorphous erythrocytes in the urinary sediment has been described as characteristic of glomerular bleeding. We studied 30 patients with histologically confirmed glomerular disorders and 25 patients with urological diseases and with hematuria. In the sediment of 10 ml urine 200 erythrocytes were counted under phase-contrast microscopy and evaluated relative to their morphology. The number of glomerular erythrocytes was expressed as a percentage. In all groups of glomerular disorders (mesangial-proliferative, membranous and membrano-proliferative glomerulonephritis, focal segmental glomerulosclerosis, glomerulonephritis of systemic disease, thinning of the glomerular basement membrane) the percentage of glomerular erythrocytes varied widely between 2 and 100%. In 7 cases less than 10% of glomerular erythrocytes were found. There was no correlation between the percentage of glomerular erythrocytes and the degree of renal insufficiency, hematuria or proteinuria. On the other hand, in patients with hematuria from the lower urinary tract, erythrocytes were uniformly non-glomerular in shape (95-100%). We conclude that 10-20% or more of glomerular erythrocytes in the urinary sediment are a good indicator of glomerular disease, whereas lower figures do not definitely rule out a glomerular origin for hematuria.

Erythrocytes↗

PubMed1985

[Benefits of routine automatic blood picture differentiation].

The benefits of automated blood smear differential cell counting as a supplementary laboratory examination have been studied. The investigations focussed on patients of whom hematology requisitions were limited to total leukocyte count and hemoglobin determination. The specimens were derived from patients of departments of surgery and obstetrics and gynecology. For specimen collection the vacutainer system was used. The blood smears were prepared in a Coulter Electronics slide spinner, stained with a Hematek II slide stainer and analyzed in the Coulter Electronics Diff 3-50 cell classifier. A total of 1700 blood smears were examined. Following processing of each sample, the classification of each cell was inspected. Corrections were performed, if necessary, and the number of classification changes performed for each smear was registered. Using the in-house normal ranges, 34.5% were pathological smears. Since this group included a large number of borderline cases, new discrimination limits for clinically relevant pathological findings were set empirically. According to these wider ranges, the fraction of pathological slides amounted to 15.2%. Among these, immature granulocytes, eosinophilia and lymphopenia were the most frequent pathological findings. Microscopic control proved in 57.6% of the total number of smears. This complemental procedure was not found to be time-consuming.

Automation↗

PubMed1983

[Automatic blood smear differentiation using the Coulter Electronics Diff 3-50 system].

The Coulter Electronics Diff 3-50 consists of a slide spinner, a slide stainer and a cell classifier. The cell analyzer is composed of an optical system with a microscope, microprocessor, video camera and printer. The system used in this laboratory is supplemented by a video monitor. The Diff 3-50 analyzes blood cells according to the classical criteria used in hematology. It classifies 11 types of nucleated blood cells and it processes an average of 45 blood smears per hour. It features a visual control of each cell classified with a built-in mechanism for change of classification by the operator if necessary. Moreover, the system estimates leukocyte and platelet count and generates a quantitative estimate of platelet number. Blood smears of 507 blood samples from patients admitted to the hospital were included in the present study. They were analyzed twice, first by the Diff 3-50, and secondly by visual checking of the automatic classification of each cell. The results of the two procedures were then compared. The findings indicate an overall false negative error of 1.4% and an overall false positive error of 4.3%. Major differences were found, though not consistently, only when the classification by the Diff 3-50 of the band neutrophils was compared with the visual classification performed by the operator. Lymphocytes and monocytes correlated well when both procedures were compared. Blasts present in 5 blood smears were recognized by the classifier. The Diff 3-50 identified immature granulocytes in 47 out of 48 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Cell Count↗

PubMed1972