Effect of Levosimendan Compared to Conventional Inotropic Agents on Hemodynamics and Outcome in Patient with Poor LV Function Undergoing Cardiac Surgery

BACKGROUND: Patients undergoing heart surgery involving cardiopulmonary bypass (CPB) experience global myocardial ischemia with subsequent reperfusion which, despite cardioplegic protection, may result in different degrees of transient ventricular dysfunction. Levosimendan is a “calcium sensitisersâ€, it improves myocardial contractility by sensitising troponin C to calcium without increasing myocardial oxygen consumption and without impairing relaxation and diastolic function. AIM: To evaluate the adding effect of a calcium sensitiser (levosimendan) compared to the conventional inotropic and vasoactive agent used in the patient with poor left ventricular function undergoing cardiac surgery on different measured hemodynamic variables and the effect on the outcome. METHODS: It is prospective observational studies were patients were divided into 2 groups of 30 patients each. The first Group received conventional inotropic and vasoactive treatment at different doses, while the other group received levosimendan additionally at a loading dose of 6-12mic/kg according to mean arterial pressure over 0.5 hr followed by 24 hrs infusion at 0.05 to 0.2 mic/kg/min. Hemodynamic data were collected at the end and 30 minutes after CPB, after that at 6, 12, 24, and 36 hours post CPB. Mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR), mixed venous saturation (Svo2), and base deficit (BD) were measured. RESULTS: Levosimendan had significantly improved postoperative hemodynamic values as in the mixed venous pressure at different times postoperative (p < 0.05), also the base deficit at different times postoperative (p < 0.05), while there was a significant reduction in systemic vascular resistance as decreased mean arterial pressure in levosimendan group compared to conventional group at 6hrs postoperative mean 77.50 ± 10.81 vs 83.73 ± 10.81 with (p = 0.029), and at 12 hrs postoperative mean 77.37 ± 10.10vs 84.23 ± 13.81 with (p = 0.032), and there was no significant difference in heart rate at different times postoperative between both groups (p > 0.05), while there was no significant effect on mortality between both groups (p = 0.781). CONCLUSION: Levosimendan had improved hemodynamic parameters significantly with no effect on mortality compared to conventional inotropic agents in a patient with poor left ventricular function undergoing cardiac surgery

Comparative study between purse–string suture and peritoneal disconnection with ligation techniques in the laparoscopic repair of inguinal hernia in infants and children

Background Laparoscopic hernia repair in children is becoming more popular nowadays. A lot of laparoscopic techniques were described to repair inguinal hernia in infants and children; however, there are few reports on laparoscopic disconnection of the hernia sac at internal inguinal ring (IIR) as a method for hernia repair.Purpose The objective of this study was to compare intracorporeal purse–string suturing leaving the hernia sac in continuity and laparoscopic disconnection of the hernia sac at IIR and proximal closure of the peritoneum for repair of inguinal hernia in infants and children. A randomized prospective study was carried out in the Pediatric Surgery Unit of Alexandria University Hospitals (Alexandria, Egypt) on 40 male children.Patients and methods Forty male patients (48 repairs) were randomized into two equal groups (n= 20). Group A was subjected to intracorporeal purse–string suturing around the IIR leaving the hernia sac in continuity. Group B was subjected to disconnection of the hernia sac from the parietal peritoneum at the level of IIR, followed by proximal closure of the peritoneum. Inclusion criteria were as follows: male inguinal hernia, either unilateral or bilateral, and age between 6 months and 12 years. Exclusion criteria were as follows: female inguinal hernia, hernia with undescended testicles, recurrent inguinal hernia, and previous major lower abdominal surgery. The main outcome measurement was recurrence, and secondary outcome measurements were operative time, hospital stay, intraoperative complications, postoperative hematoma, postoperative testicular atrophy, and postoperative hydrocele formation.Results There were no significant differences between the two groups as regards age, sex, and mode of presentation. All cases were completed laparoscopically without conversion. Group A showed a significantly higher rate of recurrence as well as hydrocele formation compared with group B; however, there was no difference as regards the operative time, hospital stay, and testicular atrophy.Conclusion Laparoscopic hernia repair using the peritoneal closure following disconnection of the hernia sac is a safe and feasible method for hernial repair with minimal complications. It has a lower recurrence rate compared with the purse–string suturing alone, with no added risk for injury to the vas and vessels

Comprehensive performance analysis of perovskite solar cells based on different crystalline structures of MAPbI 3

Perovskite solar cells (PSCs) have shown high optical absorption and consequently provide high conversion efficiency with stable performance. In our work, CH3NH3PbI3 (MAPbI3) as an absorber layer is analyzed for different crystalline structures. Cubic, tetragonal, and orthorhombic phases of perovskite material are investigated to check the impact of the crystalline structure on the solar cell performance. Both density of states and band structure are studied using Quantum-ESPRESSO package depending on density functional theory. Then, all relevant parameters were employed in SCAPS software and comprehensive study was done for examining the effect of the crystalline structure of perovskite layer on the solar cell performance. In-depth, analyses were conducted to evaluate key parameters, including open circuit voltage (Voc), short circuit current (Isc), fill factor (FF), and power conversion efficiency (PCE) considering the variations of perovskite layer thickness and bulk defect densities. The obtained results indicate that cells with cubic MAPbI3, which shows a notably higher bandgap of 1.7 eV and an enhanced optical absorption coefficient, especially in the higher wavelength range (around 105 cm−1), show better performance for almost all three scenarios. Cubic MAPbI3 cells achieve relatively higher peak efficiency of 26% when the absorber layer thickness is almost 900 nm. The investigation into absorber bulk defect densities reveals the critical role of defect levels in PSC performance. Adjusting defect levels from 1014 cm−3 to 1018 cm−3 results in deteriorating trends in Voc, Jsc, FF, and PCE. Jsc remains stable until a defect level of 1017 cm−3, highlighting a threshold where defects begin to impact charge carrier generation and separation. Doping effect has been studied, PCE remains stable until a critical doping level of 1016 cm−3 after which it drops significantly which indicates that doping is cautioned against due to its adverse effects on material and carrier transport. This finding holds significant promise for experimental solar cell fabrication, as it suggests that cubic MAPbI3’s superior bandgap and enhanced optical absorption could lead to more efficient and robust photovoltaic devices in real-world applications

Smart Touch Radiofrequency Catheter Ablation versus Cryoballoon Ablation of Pulmonary Veins in Patients with Paroxysmal Atrial Fibrillation

AIM: Evaluation of the safety and efficacy of pulmonary veins isolation in patients with paroxysmal atrial fibrillation (AF) using two new different technologies, cryoballoon (CB) ablation and radiofrequency ablation with contact force (CF)-sensing catheters. METHODS: Prospective single-center evaluation, carried out from January 2016 to June 2018 in Critical Care Medicine Department – Cairo University, comparing CF radiofrequency (Thermocool® SmartTouch, Biosense Webster, Inc.) (CF group) with CB ablation (Arctic Front Advance 28 mm CB, Medtronic, Inc.) (CB group), in regards to procedural safety and efficacy, as well as recurrence at 12 months. Overall, 50 consecutive patients were enrolled (25 in each group). RESULTS: The characteristics of patients of both the groups were similar (46.9 ± 11.2 years, the proportion of women 36%, mean documented AF duration 3 ± 2.3 years, mean CHA2DS2-VASc score 1.4 ± 1.3, and mean HAS-BLED 1.4 ± 0.6). Duration of the procedure was significantly lower in the CB group (171.7 ± 15.24 vs. 199.3 ± 18.94 min, p = 0.002), with a longer duration of fluoroscopy and X-ray exposure in the CB group than the CF group but statistically non-significant difference (58.60 ± 11.57 vs. 48.7 ± 13.86 min and 6273 ± 4934 cGy cm² vs. 6853 ± 5069 cGy cm², p = 0.1 and p = 0.2, respectively). Overall complication rate was similar in both groups: 2 (8%) in each group. At 12 months, AF recurrence occurred in 7 patients (28%) in the CF group and in 9 patients (36%) in the CB group (log rank p = 0.682). CONCLUSION: Pulmonary vein isolation using CF-guided RF and second-generation CB leads to comparable single-procedure arrhythmia-free survival at up to 12 months with similar overall complication rate

New Variable Step-Size NLMS Algorithm for Adaptive Noise Cancellation

Numerous Variable Step-Size Normalized Least Mean Square (VSS-NLMS) algorithms have been proposed to solve the problems of fast convergence rate and low value of steady-state misadjustment in the past three decades. In this paper we propose a new VSS-NLMS algorithm that employs the estimated power ratio of the adaptive filter to control the step-size update. The algorithm has a large step size in the initial stages to speed up the convergence rate, and then the step size is adjusted to maintain a low value of steady-state misadjustment. The performance of the proposed algorithm is evaluated for Adaptive Noise Canceller (ANC) using different speech signal with stationary and non-stationary noise added to it. The computer simulation highlights that the proposed algorithm has very fast convergence rate while maintaining a very low value of steady-state misadjustment

Visual image and expression directed to the child in Media Age

Abstract:Designing the visual image directed to the child is considered to be a big challenge for the artist or designer who is forming it, as the visual image is the strongest communication channel in the age of media because it carries meaning smoothly through expressive content. The artists or designer uses the design theories of visual image to form its elements expressing the message carried to children actively.The research contains the definition of visual image and how to form it based on art composition forming theories of the visual image, the study of the meaning definition and expressive characteristics that are in the children drawings and wording shapes for knowing the best ways to communicate with their sentiment. Keywords:Visual image – expression – children drawings characteristics Research Aims:1. Studying the dimensions of the visual image directed to the Pre-adolescent child (9 to 12 years old) contributes to activating the elements of his visual culture.2. Study of the basic formative construction of expression in child’s drawings achieves the target of communication message carried to him.Research Methodology:• The researcher uses the descriptive method followed by an analytical study to identify the concept of the visual image and expression addressed to the "Pre-adolescent" child (9 to 12 years old) to identify the set standards or the necessary ones of it.Research Results:1- That the formative elements of the visual image has to match the expressive content of the message carried.2- Design theories adds an aesthetic and expressive values to the visual image.3- The child has his own way of expressing that the artist needs to study to find the best way to communicate with his sentiment.4- The visual image and expression are considered to be the most powerful way to influence child’s perception.Most important references:1- Dr Ahmed Hamdy Mahmoud- Ma Wara’ Al Fen - General Egyptian Book Organization - 19932- Malameh Wa Qadaya Al Fen Al Tashkily Al Mo’aser - Dr Saleh Reda - Maktabet Al Osra - 200