Osman Ozdemir

Unsteady 2-D chlorine transport in water supply pipes

Abstract Water supply networks are generally modelled for a day or longer time period. Under most circumstances, it is normal to omit the dispersive movement of chlorine and to assume that the convective transport dominates over dispersion. However, during night time operations the velocities are significantly decreased. This radical change in the velocity may therefore lead to the following question: can the available convection based quality models predict the chlorine concentrations accurately in time and space? An improved water quality model implies accurate estimation of concentrations at nodes in time and space at all levels of branching. To enhance the utility of water quality models dispersion may also be taken into account. In this paper, an effort that led to the development of an unsteady 2-D convective–dispersive model is presented, and the model output is compared with the experimental results.

Realistic numerical simulation of chlorine decay in pipes

The objective of the present study is to develop a numerical mass transport model that can simulate chlorine disappearance mechanisms under low flow conditions. The model accounts for axial convection and radial diffusion in a pipe under turbulent, transitional and laminar flow regimes and uses realistic velocity profiles. The bulk decay coefficient assumed to be constant in previous models is taken to be a function of residence time of water in pipes based on the findings of the experiments by laboratory tests. Furthermore, a methodology is introduced to convert simple one dimensional model solutions into refined results as if they were calculated by a much more precise two dimensional model.

Success of booster chlorination for water supply networks with genetic algorithms

The chlorination of drinking water distribution networks is usually carried out at the supply source. However, chlorine may disappear in some portions or at distant points within a network. In this case, one or more booster chlorination stations must be built in the network in order to observe detectable chlorine residual at all levels of branching. Network hydraulic values, tank water levels and chlorine concentrations may vary over the course of one day because of changes in consumer demand. For this reason, the optimal location of a booster chlorination station, injection rates-and scheduling must be considered together. In this research, the locations, injection rates and scheduling of chlorine booster stations were studied using genetic algorithms. The results indicate that booster disinfection can significantly increase the desired residual concentrations above the minimum limit while helping to reduce variability in nodal concentrations. The objective of the study is to satisfy minimum and maximum required chlorine residual at every point in the network while minimizing chlorine consumption as much as possible. In order to find a hydraulic solution and chlorine concentration distribution in a network, EPANET software was used. In the solution phase, genetic algorithms and EPANET software were run interactively. The algorithm developed was used on an existing network given in the literature and solutions were compared with the current status of the network.

Cardiac Troponin T in Children With Acute Rheumatic Carditis

The existence of cardiac damage in active rheumatic carditis patients is unknown, especially in those without pericarditis. The aim of this study was to determine cardiac myocyte damage using cardiac troponin T (cTnT) measurements in active rheumatic carditis. The levels of creatine kinase MB isoenzyme (CK-MB), cTnT, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), cardiothoracic ratio (CTR), and fractional shortening (FS) were compared using Mann–Whitney U test between 28 patients with active rheumatic carditis and 32 controls (healthy children). Association of cTnT levels with ESR, CRP, and CTR was evaluated with Spearman correlation analysis. ESR, CRP, cTnT levels, and CTR were statistically higher in the patients than in the controls. There were no differences between the groups for CK-MB levels and FS. No relationships were found between cTnT levels and ESR, CRP, and CTR in the patient group. The results of the study suggest that when cTnT levels are within non-pathological range, there is no serious cardiac damage; however, statistically significant increases in cTnT levels may indicate minor damages in patients with active carditis due to acute rheumatic fever.

Neuron-specific enolase and S100B protein in children with carbon monoxide poisoning: children are not just small adults.

INTRODUCTION The aim of this study was to evaluate the role of S100B protein and neuron-specific enolase (NSE) in children with carbon monoxide (CO) poisoning. METHODS In this prospective, case-controlled study, children with CO poisoning were recruited. Patient demographics features and Glasgow Coma Scale (GCS) were recorded. Blood samples were collected from all children with CO poisoning at their admission to the hospital and at 3 and 6 hours after admission. Levels of NSE and S100B were measured. The control group consisted of age-matched healthy children. RESULTS A total of 30 children with CO poisoning (mean age, 7.88 ± 3.75 years; 17 boys) and 30 healthy children (mean age, 8.16 ± 3.05 years; 7 boys) were enrolled in the study. Mean carboxyhemoglobin level (%) measured at admission was 30.05 ± 8.00. Serum NSE levels of the children with CO poisoning were significantly higher than those of children from the control group at 0 hour and also at 3 and 6 hours (P < .001, P = .001, and P = .005, respectively). Serum S100B protein levels were similar between the 2 groups at 0 and 3 and 6 hours (P > .05). Serum NSE levels of patients with CO poisoning demonstrated a negative correlation with the admission GCS scores. No correlation was found between GCS scores and S100B protein levels. CONCLUSION We have shown that NSE levels increase in CO-associated hypoxic brain damage in accordance with clinical findings. We have also found that, contrary to the studies conducted on adults, S100B protein levels do not increase in response to hypoxic brain damage.

Two unusual presentations of acute rheumatic fever

Patients with acute rheumatic fever sometimes present with atypical signs and symptoms. In these circumstances, the Jones criterions may not be sufficient to make a clinical diagnosis. We describe here two patients with unusual presentations, highlighting that, both in regions where the disease is endemic, or where it is seen only sporadically, physicians should be more alert and careful in making the diagnosis.

Application of Genetic Algorithms for Booster Chlorination in Water Supply Networks

The chlorination of drinking water distribution networks is usually carried out at the supply source. However, chlorine may disappear in some portions or at distant points within a network. In this case, one or more booster chlorination stations must be built in the network in order to observe detectable chlorine residual at all levels of branching. Network hydraulic values, tank water levels and chlorine concentrations may vary over the course of one day because of changes in consumer demand. For this reason, the optimal location of a booster chlorination station, injection rates and scheduling must be considered together. In this research, the locations, injection rates and scheduling of chlorine booster stations were studied using genetic algorithms. The results indicate that booster disinfection can significantly increase the desired residual concentrations above the minimum limit while helping to reduce variability in nodal concentrations. The objectives were satisfied with a small increase in chlorine consumption compared to conventional disinfection only at the source. In order to find a hydraulic solution and chlorine concentration distribution in a network, EPANET software was used. In the solution phase, genetic algorithms and EPANET software were run interactively. The algorithm developed was used on an existing network given in the literature and solutions were compared with the current status of the network.

Echocardiographic findings in children with Marfan syndrome

Background The typical cardiac manifestations of Marfan syndrome are aortic regurgitation with progressive dilatation of the aortic root, which may cause dissection and rupture of the ascending aorta, mitral valve prolapse and mitral valve regurgitation. In this study, we aimed to show echocardiographic findings in 11 patients with Marfan syndrome. Methods Diagnosis of Marfan syndrome was based on the Ghent criteria. All patients had a full echocardiographic evaluation. During the evaluation, we investigated the presence of mitral valve prolapse, mitral valve regurgitation, tricuspid valve prolapse, dilatation of the aortic root, and aortic regurgitation. Results Eleven patients were diagnosed as Marfan syndrome (seven male, four female, age 4–14 years). All had mitral valve prolapse (nine with mitral valve regurgitation). Among these 11 patients, seven had accompanying tricuspid valve prolapse, six had dilatation of the aortic root and two had aortic regurgitation. Conclusion Eleven patients in our clinic were diagnosed as Marfan syndrome since they had distinct characteristics of marfanoid phenotype. Echocardiographic evaluation of these patients showed marked heart valve involvement. In Marfan syndrome, it is known that the aortic valve is affected following mitral valve involvement. In our experience, aortic root dilatation is less common. However, particular attention should be given to following up aortic root status with non-invasive echocardiography to institute measures to prevent complications.

Fibrillin-1 gene intron 56 polymorphism in Turkish children with mitral valve prolapse.

OBJECTIVE Mitral valvar prolapse is the most common anomaly of the mitral valve apparatus throughout childhood. Fibrillin is one of the structural components of the elastin-associated microfibrils found in the mitral valve. A case-controlled study has performed to investigate the relationship between fibrillin 1 gene intron 56 polymorphism and risk of mitral valvar prolapse in Turkish children. PATIENTS AND METHODS A total of 77 patients with mitral valvar prolapse diagnosed by clinical evaluation and echocardiography and 89 normal children of same age and sex were studied. The fibrillin-1 gene intron 56 polymorphism was identified by the polymerase chain reaction-based restriction analysis. RESULTS There was a significant difference in the distribution of fibrillin-1 gene intron 56 genotypes (p = 0.0001) and allelic frequency (p = 0.0001) between the cases and the controls. CONCLUSIONS Patients with mitral valvar prolapse have higher frequencies of fibrillin-1 gene intron 56 GC genotypes. Healthy children have higher frequencies of fibrillin-1 gene intron 56 CC genotypes. We speculate that the higher frequency of fibrillin-1 gene intron 56 G-allele increases the risk of mitral valvar prolapse.

Prognostic significance of sICAM-1 and sVCAM-1 molecules for cardiac surgery in pediatric patients with pulmonary hypertension

OBJECTIVE To investigate preoperative and postoperative blood levels of soluble intercellular and vascular cell adhesion molecules (sICAM-1, sVCAM-1) in patients with and without pulmonary hypertension (PAH) due to congenital heart disease and left to right (L-R) shunt and to determine whether these molecules can be used as reliable prognostic markers of endothelial activity to predict surgical outcomes. METHODS In this observational prospective cohort study; 42 patients, operated for L-R shunt were divided into three groups. Group 1: L-R shunt without PAH, Group 2: L-R shunt with PAH, Group 3: L-R shunt with PAH and postoperative low cardiac output syndrome (LCOS). Their sICAM-1 and sVCAM-1 levels were measured preoperatively (sICAM-0, sVCAM-0) and on the first (sICAM-1, sVCAM-1) and fifth postoperative days (sICAM-2, sVCAM-2).ROC curve for various cut-off levels of sICAM-0, sVCAM-0 in differentiating PAH patients with and without LCOS. RESULTS In Group 3, sICAM-0 and sVCAM-2 levels were higher than Group 1 and 2. The ROC curve demonstrated a significant association between sICAM-0 in patients with L-R shunt and PAH (Group 2 and 3) and the development of LCOS (area under the curve: 0.98, p<0.01 and 0.97, p<0.01, respectively). At a sICAM-0 concentration >359 ng/mL, there was a sensitivity of 90% and specificity of 95% for identification of LCOS in patients with L-R shunt and PAH (AUC: 0.98, 95% CI: 0.95-1.02, p<0.01). CONCLUSION High preoperative sICAM-1 molecule may be used to predict postoperative dichotomous outcome in patients with PAH associated with L-R shunt.