Two-level multivariable control system of dissolved oxygen tracking and aeration system for activated sludge processes.

The problem of tracking dissolved oxygen is one of the most complex and fundamental issues related to biological processes. The dissolved oxygen level in aerobic tanks has a significant influence on the behavior and activity of microorganisms. Aerated tanks are supplied with air from an aeration system (blowers, pipes, throttling valves, and diffusers). It is a complex, dynamic system governed by nonlinear hybrid dynamics. Control of the aeration system is also difficult in terms of control of the dissolved oxygen. In this article, a two-level multivariable control system for tracking dissolved oxygen and controlling an aeration system is designed. A nonlinear model predictive control algorithm was applied to design controllers for each level. This overall hierarchical control system was validated by simulation based on real data records provided by a water resource recovery facility located in Kartuzy, Northern Poland. The effect of control system parameters and disturbances was also investigated.

Protein kinase g iα inhibits pressure overload-induced cardiac remodeling and is required for the cardioprotective effect of sildenafil in vivo.

BACKGROUND: Cyclic GMP (cGMP) signaling attenuates cardiac remodeling, but it is unclear which cGMP effectors mediate these effects and thus might serve as novel therapeutic targets. Therefore, we tested whether the cGMP downstream effector, cGMP-dependent protein kinase G Iα (PKGIα), attenuates pressure overload-induced remodeling in vivo. METHODS AND RESULTS: The effect of transaortic constriction (TAC)-induced left ventricular (LV) pressure overload was examined in mice with selective mutations in the PKGIα leucine zipper interaction domain. Compared with wild-type littermate controls, in response to TAC, these Leucine Zipper Mutant (LZM) mice developed significant LV systolic and diastolic dysfunction by 48 hours (n=6 WT sham, 6 WT TAC, 5 LZM sham, 9 LZM TAC). In response to 7-day TAC, the LZM mice developed increased pathologic hypertrophy compared with controls (n=5 WT sham, 4 LZM sham, 8 WT TAC, 11 LZM TAC). In WT mice, but not in LZM mice, phosphodiesterase 5 (PDE5) inhibition with sildenafil (Sil) significantly inhibited TAC-induced cardiac hypertrophy and LV systolic dysfunction in WT mice, but this was abolished in the LZM mice (n=3 WT sham, 4 LZM sham, 3 WT TAC vehicle, 6 LZM TAC vehicle, 4 WT TAC Sil, 6 LZM TAC Sil). And in response to prolonged, 21-day TAC (n=8 WT sham, 7 LZM sham, 21 WT TAC, 15 LZM TAC), the LZM mice developed markedly accelerated mortality and congestive heart failure. TAC induced activation of JNK, which inhibits cardiac remodeling in vivo, in WT, but not in LZM, hearts, identifying a novel signaling pathway activated by PKGIα in the heart in response to LV pressure overload. CONCLUSIONS: These findings reveal direct roles for PKGIα in attenuating pressure overload-induced remodeling in vivo and as a required effector for the cardioprotective effects of sildenafil.

Early decline of pancreatic function in cystic fibrosis patients with class 1 or 2 CFTR mutations.

BACKGROUND: Most cystic fibrosis (CF) patients develop steatorrhea and require pancreatic enzyme replacement therapy. However, there are few data regarding the decline of exocrine pancreatic function within the first years of life in relation to CF genotype. We assessed the decline of pancreatic function in CF infants carrying class 1 or 2 CFTR mutations who were diagnosed in a neonatal screening program. MATERIALS AND METHODS: Twenty-eight CF patients were included in the study and 27 completed the study. In all subjects, fecal pancreatic elastase-1 concentrations and fecal fat excretion were scheduled to be determined at diagnosis, at 6 months of age and subsequently at 6-month intervals. RESULTS: In all CF patients, fecal pancreatic elastase-1 concentrations of the first assay after diagnosis (3 to 4 months of age) were lower than the cut-off level for normals of <200 microg/g stool. Steatorrhea was found in 81.5% of these subjects. At the age of 6 months, all screened CF subjects had fecal pancreatic elastase-1 concentrations <100 microg/g and at the age of 12 months all were pancreatic insufficient. At that time, having proved pancreatic insufficiency in all studied subjects, we stopped the scheduled further assessment. CONCLUSION: CF patients require careful monitoring of pancreatic status from diagnosis onwards. In patients carrying class 1 or 2 CFTR mutations, pancreatic insufficiency develops in the first months of life. The proper assessment of pancreatic insufficiency and intestinal malabsorption is crucial for the early introduction of pancreatic enzymes.

[Evaluation of some anthropometric and clinical parameters in children with cystic fibrosis]. / Charakterystyka wybranych parametrów antropometrycznych i klinicznych u dzieci chorych na mukowiscydoze.

UNLABELLED: The aim of this study was to evaluate some antropometric and clinical parameters in children with cystic fibrosis. Studies involved 34 patients with cystic fibrosis: 13 girls (38.24%) and 21 boys (61.76%) in the age of 6 to 18 (x +/- SD = 12 +/- 3,12 lat). VARIABLES: antropometric measurements (height, body weight, circumference of the chest), spirometry, 6 minute walkin test (6MWT), pulse oximetry had been measured for 4 consecutive years. Significant difference was found in dynamics of change of body weight in boys with cystic fibrosis in comparison with healthy boys in the age: 9-11 and 12-14 ( p< 0,001 and p< 0,03 respectively). Analogous differences were found in: dynamics of change of height in girls with cystic fibrosis in comparison to healthy girls in the age 12-14 (p<0.05) and in boys with cystic fibrosis in comparision to healthy boys in the age 9-11 (p< 0.001). Significant changes were observed in values of FEV1 and FVC EX in consecutive 4 years of observation (p<0.002) and p<0.002 respectively). Loss of saturation in subjects during 6 MWT was significant (p< 0,001); (x=2.69%). The mean of oxygen arterial blood saturation was 96.44% (initial level); 93.75% (post-test levels). There was correlation between the post-test level of saturation and circumference of the chest in girls with cystic fibrosis.

Serum lipase after secretin stimulation detects mild pancreatic involvement in cystic fibrosis.

BACKGROUND: The assessment of severe pancreatic insufficiency in cystic fibrosis (CF) is not a diagnostic problem. However, identification of mild cases remains a challenge. The aim of this study was to assess the ability of serum lipase after secretin stimulation to identify mild pancreatic insufficiency in patients with CF. MATERIAL AND METHODS: Thirty patients with CF and pancreatic insufficiency (CF-PI) and 30 patients with CF and pancreatic sufficiency (CF-PS) were studied. Thirty healthy subjects with no known gastrointestinal disease served as controls. In all subjects, fecal fat excretion, fecal elastase-1 (E1) concentration and basal and secretin-stimulated serum lipase concentration were measured. RESULTS: All patients with CF-PI and 3 with CF-PS had abnormally low fecal E1 concentrations. The remaining 27 CF-PS patients and all controls had normal values. Basal and post-stimulation lipase levels were extremely low in patients with CF-PI. Mean basal and poststimulation serum lipase concentrations were significantly higher in CF-PS who had normal fecal E1 concentrations but were still below those of controls (P < 0.001). Among the 27 CF-PS patients with normal fecal elastase, high basal and poststimulation lipase values were found in 6 and 17 patients respectively. CONCLUSION: In patients with CF-PS who have normal fecal elastase-1 concentration, the measurement of basal or secretin-stimulated lipase levels might be helpful in identifying the progression of the destructive process in the pancreas.

Fecal elastase-1 cut-off levels in the assessment of exocrine pancreatic function in cystic fibrosis.

BACKGROUND: Fecal elastase-1 (E1) test is a sensitive and specific indirect test. However, there are few data on the best cut-off level in the assessment of exocrine pancreatic function in cystic fibrosis (CF). MATERIAL AND METHODS: In 725 CF patients and 243 healthy subjects (HS) from Greece, Russia, Poland and the United Kingdom, E1 concentrations were measured. The best cut-off levels for the discrimination between CF and HS (for whole group as well as for individual countries) were calculated. RESULTS: The best cut-off level for the differentiation between CF pancreatic insufficiency and normal pancreatic function in HS was found to be 184 microg/g of feces. However, some inter-country differences were stated. E1 concentrations in the UK subgroup were significantly lower than those found in Polish and Russian CF patients. E1 concentrations in Greek patients were significantly higher than in the other countries. However, E1 concentrations in Delta F508 homozygotes were very similar in all studied subgroups. IN CONCLUSION: In clinical practice, instead of a single best cut-off level for the E1 test, we suggest using a range of values (160-200 microg/g). The presence of different best cut-off levels within countries is a practical consequence of the different distribution of pancreatic function.