Newborn Pulse Oximetry Screening for Detecting Congenital Heart Disease: Experience at a Tertiary Care Center.

Background: Congenital heart disease (CHD) remains the number one birth defect worldwide. Pulse oximetry screening (POS) is a widely used CHD screening modality effective in detecting critical lesions. This study is aimed at assessing the accuracy and cost-effectiveness of POS in a cohort of term well-babies admitted to a regular nursery in a tertiary care center. Methods: We reviewed the charts of term babies admitted to our regular nursery over a period of one year. The results of POS and the findings of echocardiography were collected. Similarly, we explored the records of our fetal echocardiography program to identify the fetuses screened for CHD during the same period. Results: 900 term babies were born and admitted to newborn nursery at our center, and 69 fetuses were evaluated by our fetal cardiology team during the study period. None of our term babies had a positive POS at birth or 24 hours of age. However, 56 babies had a cardiac echo before hospital discharge due to suspicious findings on physical examination or a family history of CHD. A simple noncritical CHD was noted in 10 of them. Additionally, 53 babies underwent echocardiography within the first five years of life; a simple CHD was noted in 6 of them. In parallel, 21 of our fetuses were found to have CHD: 16 simple CHD and 5 critical CHD (CCHD). Conclusion: Despite its cost-effectiveness and efficacy in screening for CCHD, POS is suboptimal for detecting simple CHD. In the absence of a proper prenatal screening and fetal echocardiography program, POS remains a cost-effective modality for detecting CCHD.

Ultrahigh Mass Activity Pt Entities Consisting of Pt Single atoms, Clusters, and Nanoparticles for Improved Hydrogen Evolution Reaction.

Platinum is one of the best-performing catalysts for the hydrogen evolution reaction (HER). However, high cost and scarcity severely hinder the large-scale application of Pt electrocatalysts. Constructing highly dispersed ultrasmall Platinum entities is thereby a very effective strategy to increase Pt utilization and mass activities, and reduce costs. Herein, highly dispersed Pt entities composed of a mixture of Pt single atoms, clusters, and nanoparticles are synthesized on mesoporous N-doped carbon nanospheres. The presence of Pt single atoms, clusters, and nanoparticles is demonstrated by combining among others aberration-corrected annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, and electrochemical CO stripping. The best catalyst exhibits excellent geometric and Pt HER mass activity, respectively ≈4 and 26 times higher than that of a commercial Pt/C reference and a Pt catalyst supported on nonporous N-doped carbon nanofibers with similar Pt loadings. Noteworthily, after optimization of the geometrical Pt electrode loading, the best catalyst exhibits ultrahigh Pt and catalyst mass activities (56 ± 3 A mg-1 Pt and 11.7 ± 0.6 A mg-1 Cat at -50 mV vs. reversible hydrogen electrode), which are respectively ≈1.5 and 58 times higher than the highest Pt and catalyst mass activities for Pt single-atom and cluster-based catalysts reported so far.

Access to training in neurosurgery (Part 2): The costs of pursuing neurosurgical training.

Introduction: Opportunities for in-country neurosurgical training are severely limited in LMICs, particularly due to rigorous educational requirements and prohibitive upfront costs. Research question: This study aims to evaluate financial barriers aspiring neurosurgeons face in accessing and completing neurosurgical training, specifically in LMICs, in order to determine the barriers to equitable access to training. Material and methods: In order to assess the financial costs of accessing and completing neurosurgery residency, an electronic survey was administered to those with the most recent experience with the process: aspiring neurosurgeons, neurosurgical trainees, and recent neurosurgery graduates. We attempted to include a broad representation of World Health Organization (WHO) geographic regions and World Bank income classifications in order to determine differences among regions and countries of different income levels. Results: Our survey resulted in 198 unique responses (response rate 31.3%), of which 83% (n â€‹= â€‹165) were from LMICs. Cost data were reported for 48 individual countries, of which 26.2% were reported to require trainees to pay for their neurosurgical training. Payment amounts varied amongst countries, with multiple countries having costs that surpassed their annual gross national income as defined by the World Bank. Discussion and conclusions: Opportunities for formal neurosurgical training are severely limited, especially in LMICs. Cost is an important barrier that can not only limit the capacity to train neurosurgeons but can also perpetuate inequitable access to training. Additional investment by governments and other stakeholders can help develop a sufficient workforce and reduce inequality for the next generation of neurosurgeons worldwide.

Electron Beam Transparent Boron Doped Diamond Electrodes for Combined Electrochemistry-Transmission Electron Microscopy.

The majority of carbon based transmission electron microscopy (TEM) platforms (grids) have a significant sp2 carbon component. Here, we report a top down fabrication technique for producing freestanding, robust, electron beam transparent and conductive sp3 carbon substrates from boron doped diamond (BDD) using an ion milling/polishing process. X-ray photoelectron spectroscopy and electrochemical measurements reveal the sp3 carbon character and advantageous electrochemical properties of a BDD electrode are retained during the milling process. TEM diffraction studies show a dominant (110) crystallographic orientation. Compared with conventional carbon TEM films on metal supports, the BDD-TEM electrodes offer superior thermal, mechanical and electrochemical stability properties. For the latter, no carbon loss is observed over a wide electrochemical potential range (up to 1.80 V vs RHE) under prolonged testing times (5 h) in acid (comparable with accelerated stress testing protocols). This result also highlights the use of BDD as a corrosion free electrocatalyst TEM support for fundamental studies, and in practical energy conversion applications. High magnification TEM imaging demonstrates resolution of isolated, single atoms on the BDD-TEM electrode during electrodeposition, due to the low background electron scattering of the BDD surface. Given the high thermal conductivity and stability of the BDD-TEM electrodes, in situ monitoring of thermally induced morphological changes is also possible, shown here for the thermally induced crystallization of amorphous electrodeposited manganese oxide to the electrochemically active γ-phase.

Moyamoya syndrome and stroke among pediatric sickle cell disease patients in Sudan: A cross-sectional study.

Background: Sickle cell disease (SCD) is autosomal recessive hemolytic anemia due to hemoglobinopathy commonly in Sub-Saharan Africa, and particularly in Sudan. The disease induces a pro-inflammatory cascade in the intimal layer that leads to hyperplasia and progressive stenosis in the major vessel of the circle of Willis. This is associated with the development of Moyamoya collaterals. The aim of this study is to highlight the frequency of Moyamoya syndrome in Sudanese pediatric patients with sickle cell disease presenting with stroke. Materials and methods: A descriptive cross-sectional hospital-based study was conducted in the Department of Hematology at Gaafar Ibnauf Pediatric Tertiary Hospital in Khartoum state in Sudan, in the period between March 2021 and August 2021. Secondary data has been collected from the medical record after ethical approval and informed consent. Results: A total of 104 patients were included in the study. The males were the majority, about 60 (57.7) compared to 44 (42.3%) females. More than half of our study population was in the school-age 54 compared to 42 adolescents and only 8 patients of preschool age. Only 50 out of 104 patients had diagnostic MRA which revealed features of Moyamoya syndrome in 48 (96%) patients. Motor weakness (100%), aphasia (52.9%), and facial palsy (35%) were the major stroke presentations. The left anterior circulation territory was the most common site of moyamoya features involvement in 31 patients out of 48. Conclusion: Stroke is a common problem in Sudanese pediatric patients with sickle cell disease, with a very high frequency of Moyamoya vasculopathy among patients with stroke presentation. The burden of Moyamoya syndrome in Sudanese pediatric patients with sickle cell disease is underestimated due to the cost of the available screening and diagnostic tools.

Controlling palladium morphology in electrodeposition from nanoparticles to dendrites via the use of mixed solvents.

By changing the mole fraction of water (χwater) in the solvent acetonitrile (MeCN), we report a simple procedure to control nanostructure morphology during electrodeposition. We focus on the electrodeposition of palladium (Pd) on electron beam transparent boron-doped diamond (BDD) electrodes. Three solutions are employed, MeCN rich (90% v/v MeCN, χwater = 0.246), equal volumes (50% v/v MeCN, χwater = 0.743) and water rich (10% v/v MeCN, χwater = 0.963), with electrodeposition carried out under a constant, and high overpotential (-1.0 V), for fixed time periods (50, 150 and 300 s). Scanning transmission electron microscopy (STEM) reveals that in MeCN rich solution, Pd atoms, amorphous atom clusters and (majority) nanoparticles (NPs) result. As water content is increased, NPs are again evident but also elongated and defected nanostructures which grow in prominence with time. In the water rich environment, NPs and branched, concave and star-like Pd nanostructures are now seen, which with time translate to aggregated porous structures and ultimately dendrites. We attribute these observations to the role MeCN adsorption on Pd surfaces plays in retarding metal nucleation and growth.

Port-a-Cath fracture and migration in paediatric cancer patients: incidence and management at a tertiary care centre - a 15-year experience.

INTRODUCTION: Port-a-Cath or chemoport provides prolonged central venous access for cancer patients requiring prolonged chemotherapy. Prolonged use of chemoport is associated with many complications. Dislodgement and migration of chemoport catheter is a rare and reportable complication with potentially serious consequences. METHODS: The medical charts of 1222 paediatric cancer patients admitted to the Children's Cancer Center in Lebanon who had chemoports inserted for long-term chemotherapy were retrospectively reviewed. Descriptive analysis of data was conducted. RESULTS: Chemoport fracture and migration were found in seven cases with an incidence of 0.57%. The duration of chemoport use before the event of dislodgement varied from 2 months to 102 months. Non-functioning chemoport was the most common presentation. Totally, six cases were managed successfully by loop snaring, three cases by paediatric cardiology team, and three cases by interventional radiology team. One case was managed surgically during chemoport removal. CONCLUSION: Fracture and migration of chemoport catheter is a rare complication of uncertain aetiology and with potentially serious consequences. Percutaneous retrieval, done by experienced cardiologist or interventional radiologist, is the first choice for management of this complication as it is considered as a safe and effective approach.

Transcatheter Closure of Atrial Septal Defects: Comparable Experience and Outcomes Between Developing and Developed Countries.

Atrial septal defect (ASD) is one of the most common congenital heart defects. Transcatheter device closure of ASDs is safe and effective with most of the reported data being described from developed countries. To evaluate the short and mid-term results and experience of device closure of ASDs at a tertiary center in a developing country and compare it to that from developed countries. Retrospective study based on data collection from all patients who have undergone transcatheter percutaneous device closure for ASD from January 2005 until December 2017 at the Children's Heart Center at the American University of Beirut, Medical Center, Lebanon. During the study period, a total of 254 cardiac catheterizations were performed for device closure of ASDs. The mean age of the patients was 18 ± 17.9 years with 37% being less than 6 years of age. Females were 54%. Defect size ranged from 7 to 37 mm and device size ranged from 8 to 40 mm. The procedure was executed with a success rate of 96%. Five patients had device embolization (2%); in one patient the device was snared and for the remainder the devices were removed surgically. None of the study patients had thrombus formation, neurological complications, bacterial endocarditis, or cardiac erosions. There was no mortality. Device closure of ASDs at our tertiary center in a developing country has an effective and safe profile with excellent results and low complications rates, which compare favorably to those reported from centers in developed countries.

Tracking Metal Electrodeposition Dynamics from Nucleation and Growth of a Single Atom to a Crystalline Nanoparticle.

In electrodeposition the key challenge is to obtain better control over nanostructure morphology. Currently, a lack of understanding exists concerning the initial stages of nucleation and growth, which ultimately impact the physicochemical properties of the resulting entities. Using identical location scanning transmission electron microscopy (STEM), with boron-doped diamond (BDD) serving as both an electron-transparent TEM substrate and electrode, we follow this process, from the formation of an individual metal atom through to a crystalline metal nanoparticle, under potential pulsed conditions. In doing so, we reveal the importance of electrochemically driven atom transport, atom cluster formation, cluster progression to a nanoparticle, and the mechanism by which neighboring particles interact during growth. Such information will help formulate improved nucleation and growth models and promote wider uptake of electrodeposited structures in a wide range of societally important applications. This type of measurement is possible in the TEM because the BDD possesses inherent stability, has an extremely high thermal conductivity, is electron beam transparent, is free from contamination, and is robust enough for multiple deposition and imaging cycles. Moreover, the platform can be operated under conditions such that we have confidence that the dynamic atom events we image are truly due to electrochemically driven deposition and no other factors, such as electron-beam-induced movement.