Introduction: Sudden cardiac death is common in patients on hemodialysis and may occur in the immediate post dialysis period when ventricular premature complexes are common. QT dispersion reflecting hetovogelity in ventricle repolarization has been used for predicting patients with risk of malignant arrhythmia and sudden death. The purpose of the study was to assess the effect of hemodialysis on QT dispersion (QTd) corrected QT dispersion (QTcd) and maximum QTc (QTcMax) in chronic hemodialysis patients. Methods: In this deh1ive-analytic study data of 48 patients (30 male and 18 female patients with mean age 43±16 yr) on chronic hemodialysis were studied. 12 lead ECG were recorded 5-10 minutes before and after hemodialysis in a standard setting and Na+ K+ Ca++ Po4 and Mg++ levels were also determined pre and post hemodialysis. During hemodialysis no drug therapy was used except isotonic and hypertonic NaCl infusions and sodium heparin. The maintenance drug therapy including digitalis antihypertensive antianginal and beta blocking agents was not changed. The data were analyzed using SPSS software. Results: The maximal QTd interval changed significantly from 434±12.8 ms to 443±21.33 ms (P<0.001). The QTd increased significantly from 55.87±7.5 ms to 61.27±9.09 ms (p<0.001) and QTcd from 61.18±43 ms to 68.79±10.32 ms (p<0.001). 33.33% of the patients before and 47.90% after hemodialysis had QTcMax more than 440 ms.Conclusion: Hemodialysis incrases the QTd, QTcd and QTcMax in patients with end-stage renal failure, Tuse it is likely that heterogeneity of regional ventricular repolarization increases during hemodialysis.

Background: Nocturnal hypoxia is an important factor increasing the risk of mortality in patients with chronic heart failure and is associated with atrial and ventricular arrhythmias. QT dispersion, an index of myocardial electrical activity, is used as a prognostic tool in determining future malignant arrhythmias and sudden cardiac death. In the current study we investigated the effect of nocturnal oxygen therapy (NOT) on QTd in patients with CHF.Materials and methods: In this clinical study 54 patients with CHF (EF≤40%) were enrolled. Patients were administered NOT; electrocardiography was taken before and after NOT and QTd measured each time. Paired t-test was used to compare pre- and post-NOT QTd.Results: QTd significantly decreased from 56.3±18.2 msec before NOT to 46.3±17 msec after NOT (p=0.001).Conclusion: In this study NOT decreased QTd in patients with CHF which could consequently decrease risk of malignant arrhythmias and sudden cardiac death. However, the mechanisms by which NOT decreases QTd is not clear and requires further investigation.

The need to laboratory and Computational Simulation of biological Suspensions and the microorganisntes dispersion equipment, including their advantages and disadvantages are discussed. Dispersion and evaporation of microbiological aevosols from a nazel are studied and modelled. In this regard a new computational program is presented and the results are discussed. The obtained results show that the aevosols will be evaporated after dispersion and their diameters will be reduced.By increasing nazed pressure, aerosols diameters will be reduced and their speed in air will be increased. These nazel pressure and aerosols speed are shown in model by Rinolds and Webber numbers. Increasing nazed diameter would also causes increasing Rinolds and Webber dimention less numbers.

Background: The main complication of Kawasaki disease is the Coronary Artery (CA) involvement and long term follow up of patients depends on the severity of coronary arterial aneurysms, ischemia, and thrombosis. Early diagnosis of these complications can lead to a more desirable outcome for patients. Myocardial ischemia can prolong QT dispersion and increase the risk of cardiac arrhythmias as well as sudden cardiac arrests.Also, T wave peak-to-end (Tp-Te) interval dispersion, which provides a valuable index of transmural dispersion of repolarization, can trigger the arrhythmia.Methods: We evaluated the non-corrected QT interval dispersion (QTD) and the corrected QT (QTc) dispersion and measured Tp-Te interval dispersion in 49 Iranian children (28 males and 21 females) with the diagnosis of Kawasaki disease (KD) in the acute phase and 49 age-matched controls in a prospective study from 2009 to 2012. Student's t-test and Pearson correlation were used to analyze the data. All the statistical analyses were performed through the SPSS 16. Besides, P<0.05 was considered as statistically significant.Results: Patients with KD had significantly longer QTc dispersion (0.099±0.055 s versus. 0.040±0.018 s; P<0.001), non-corrected QT dispersion (0.075±0.046 versus 0.042±0.019; P<0.001), and Tp-Te dispersion (0.047±0.054 versus 0.022±0.011; P=0.015). The patients with elevation in white blood cell count (above 15000) had a statistically significant increased in QTD (P=0.011). No significant correlation was found between coronary involvement and repolarization indexes.Conclusions: In conclusion, the QT interval (corrected or non-corrected) and the Tp-Te dispersion significantly increased in the patients with KD which shows repolarization changes during the acute phase of KD. However, there is no correlation between the QT interval and the coronary involvement.

The Max-Mean Dispersion Problem comprises selecting a subset of elements from a set while maximising the average of a measure of dispersion. We usually compute this measure of dispersion based on some distance metric between the elements of the candidate set. However, in real-world applications, this measure of dispersion could be ill-defined or vague. For example, consider the problem of building a team to execute some kinds of project. We can see the dispersion between the members of the team as the team chemistry, so the coach is interested in maximising this chemistry. In this example, it would be very difficult to compute exactly a dispersion measure for each candidate. This is due to the lack of information about how well the candidates worked together in the past. To cope with imprecise or vague information, in this paper, we propose three mixed integer linear programming models based on possibility, necessity, and credibility measures. To the best of our knowledge, this is the first approach which explicitly considers this type of uncertainty in this optimisation problem.