Investigating the Impact of Visuohaptic Simulations for the Conceptual Understanding of Electric Field for Distributed Charges

The present study assessed the benefits of a multisensory intervention on the conceptual understanding of electric field for distributed charges in engineering and technology undergraduate students. A novel visuohaptic intervention was proposed, which focused on exploring the forces around the different electric field configurations for distributed charges namely point, infinitely long line and uniformly charged ring. The before and after effects of the visuohaptic intervention are compared, wherein the intervention includes instructional scaffolding. Three single-group studies were conducted to investigate the effect among three different populations: (a) Undergraduate engineering students, (b) Undergraduate technology students and (c) Undergraduate engineering technology students from a different demographic setting. The findings from the three studies suggests that the haptic modality intervention provides beneficial effects by allowing students to improve their conceptual understanding of electric field for distributed charges, although students from groups (b) and (c) showed a statistically significant increase in the conceptual understanding. The findings also indicate a positive learning perception among all the three groups

A Comparison of Numerical Methods for Solving the Unforced Van Der Pol’s Equation

Due to the advancements in the field of computational mathematics, numerical methods are most widely being utilized to solve the equations arising in the fields of applied medical sciences, engineering and technology. In this paper, the numerical solutions of an important equation of applied dynamics: namely, the Unforced Van der Pol’s Equation (UFVDP) are obtained by reducing it to a system of two first order differential equations. The objective of this work is to investigate the efficiency of improved Heun’s (IH) method against the classical Runge-Kutta (RK4) and Mid-point (MP) methods for UFVDP equation. For analysis of accuracy, the Poincare-Lindstedt method has been used as a comparison criterion and respective error bounds are obtained. The results show that the popular RK4 method retains its better accuracy than other methods used for comparison. Keywords: Van der Pol, Runge-Kutta, Mid-point, Improved Heun’s, Poincare-Lindstedt

Neonatal sepsis following prolonged rupture of membranes in a tertiary care hospital in Karachi, Pakistan

Introduction: Prolonged rupture of membrane (PROM) is an important risk factor for early onset neonatal sepsis (EONS), which is associated with increased neonatal morbidity and mortality. We reported the incidence and associated risk factors of PROM for culture-proven EONS. Methodology: The medical records of all neonates born at Aga Khan University, Karachi over a period of five years (2007-2011) with PROM (\u3e 18 hours) were reviewed. Data about maternal and neonatal risk factors for EONS was collected and adjusted logistic regression (AOR) analysis was applied. Results: Incidence of PROM in this neonatal birth cohort was 27/1,000 live births. A total of 17 (4%) cases with blood-culture proven bacterial sepsis were identified within 72 hours of birth. Klebsiella pneumonia (n = 5; 29%) and Pseudomonas aeruginosa (n = 4; 24%) were the commonest isolates followed by group B Streptococcus (n = 3; 18%) and Escherichia coli (n = 2; 12%). Maternal fever (p = 48 hr. (p \u3c 0.001; AOR, 8.2), neonatal prematurity \u3c 34 weeks (p \u3c 0.001; AOR, 4.1) and low birth weight \u3c 1,500 grams (p 0.001; AOR, 9.8) along with neonatal thrombocytopenia and raised CRP were found to be independent risk factors associated with culture-proven EONS in PROM. Conclusions: Preventive measures should focus on recognition of these high-risk infants with prompt laboratory screening for sepsis and early institution of empirical antibiotic based on local data. Such approaches would be a safe and cost-effective strategy, especially in developing countries

Midterm results of bovine jugular vein conduit for right ventricular outflow tract reconstruction

Objective: To evaluate the midterm results of Contegra conduit. Methods: The retrospective study comprised patient record at Aga Khan University Hospital, Karachi, of conduits implanted between May 2007 and June 2012. Data collection was made from the clinical notes and from serial echocardiograms by a single cardiologist. The last followup echocardiography was done at the time of data collection in June 2012. SPSS 19 was used for statistical analysis. Results: A total of 18 conduits had been implanted (16-22mm) during the study period. Median age at the time of surgery was 9 years (range: 2.5-16 years). Early mortality was seen in 3 (16.66%) patients, but none was Contegra related. Of the remaining 15 patients, 2 (13.33%) with a diagnosis of Pulmonary Atresia-Ventricular Septal Defect with hypoplastic peripheral Pulmonary Arteries (PA), developed severe distal pressure gradient (50mmHg) across Contegra over a median period of 18 months (range: 12-24 months), with resultant severe regurgitation and needed percutaneous intervention. There was no thrombosis, calcification, anuerysmal dilation or late deaths. Conclusion: At midterm followup, Contegra conduit was associated with low re-intervention rates with satisfactory haemodynamic results. However, long-term durability must be determined for this conduit, especially in patients with Pulmonary Atresia-Ventricular Septal Defect with hypoplastic peripheral Pulmonary Arteries

Anthracycline-induced cardiotoxicity: prospective cohort study from Pakistan

Objectives: To identify anthracycline-induced acute (within 1 month) and early-onset chronic progressive (within 1 year) cardiotoxicity in children younger than 16 years of age with childhood malignancies at a tertiary care centre of Pakistan. Design: Prospective cohort study. Setting: Aga Khan University, Karachi, Pakistan. Participants: 110 children (aged 1 month–16 years). Intervention: Anthracycline (doxorubicin and/or daunorubicin). Outcome measurements: All children who received anthracycline as chemotherapy and three echocardiographic evaluations (baseline, 1 month and 1 year) between July 2010 and June 2012 were prospectively analysed for cardiac dysfunction. Statistical analysis including systolic and diastolic functions at baseline, 1 month and 1 year was carried out by repeated measures analysis of variance. Results: Mean age was 74±44 months and 75 (68.2%) were males. Acute lymphoblastic leukaemia was seen in 70 (64%) patients. Doxorubicin alone was used in 59 (54%) and combination therapy was used in 35 (32%). A cumulative dose of anthracycline /m2was used in 95 (86%). Fifteen (14%) children developed cardiac dysfunction within a month and 28 (25%) children within a year. Of these 10/15 (66.6%) and 12/28 (43%) had isolated diastolic dysfunction, respectively, while 5/15 (33.3%) and 16/28 (57%) had combined systolic and diastolic dysfunction. Seven (6.4%) patients expired due to severe cardiac dysfunction. Eight of 59 (13.5%) children showed dose-related cardiotoxicity (p= Conclusions: Incidence of anthracycline-induced cardiotoxicity is high. Long-term follow-up is essential to diagnose its late manifestations

Severe combined immune deficiency syndrome

Objective: To determine the clinico-demographic features and laboratory parameters of children with severe combined immunodeficiency (SCID). Study Design: Case series. Place and Duration of Study: Department of Paediatrics and Child Health, the Aga Khan University, Karachi, from July 2006 to July 2011. Methodology: Thirteen infants who were discharged with a diagnosis of SCID were inducted in the study. Their clinicodemographic features and laboratory parameters were determined. Descriptive statistics has been used for computing frequency and percentage. Results: The median age at diagnosis was five months; 5 infants presented within 3 months of life. Three-fourth (77%) were males. Most of the infants were severely malnourished (85%) at the time of presentation. More than two-thirds (69%) were products of consanguineous marriages. All subjects had severe lymphopenia {absolute lymphocyte count (ALC) ranging between 170 – 2280} and low T and B lymphocyte counts. Conclusion: SCID should be considered in infants presenting with severe and recurrent infections. Low ALC (\u3c 2500/mm3), is a reliable diagnostic feature of SCID. These infants should be promptly referred to a facility where stem cell transplant can be done

Empyema thoracis in children: clinical presentation, management and complications

Objective: To determine the etiology, clinical manifestation, management (medical and surgical) and complications of children with empyema thoracis in a tertiary care hospital from Karachi, Pakistan. Study Design: Descriptive, analytical study. Place and Duration of Study: Department of Surgery, The Aga Khan University Hospital, Karachi, from January 1996 to December 2010. Methodology: Medical records of admitted children aged \u3e a month to 15 years with discharge diagnosis of empyema thoracis and data was collected on demographic features, clinical manifestation, management and complications. Children managed medically were compared with those managed surgically by using interquartile range and median comparison. Mann-Whitney U test was used to compare age in months, weight (kg) and length of stay in days and presenting complaint, duration of illness; chi-square test was used to compare thrombocytosis in between groups and p-value was calculated. Results: Among the 112 patients, 59 (53%) were younger than 5 years of age. Males (n=83, 74%) were predominant. Fifty (45%) children were admitted in winter. Thirty (27%) children found unvaccinated and one fourth (n=27; 24%) were severely malnourished. Fever, cough, and dyspnea were the major presenting symptoms. Sixty-six (59%) were on some antibiotics prior to admission. Staphylococcus aureus (n=13) and Streptococcus pneumoniae (n=5) were the commonest organism isolated from blood and pleural fluid cultures. Majority of the children required some surgical intervention (n=86). Surgically managed children were younger (p=0.01); had less weight (p=0.01) and prolonged fever (p=0.02); and stayed longer in hospital (p \u3c 0.001) as compared to medically managed children. Requiring readmission (n=8), subcutaneous emphysema (n=5) and recollection of pus (n=5) were the major complications. Conclusion: Staphylococcus aureus was the major organism associated with paediatric empyema thoracis. Early identification and empiric antibiotic as per local data is essential to prevent short and long-term complications. Younger, lower weight children with prolonged fever required surgical management

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding. Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124. Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98). Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial