Amplatzer Septal Occluder-induced Transient Complete Atrioventricular Block

Percutaneous transcatheter atrial septal defect (ASD) closure is a widely used technique that has replaced open-heart surgical closure in many centers. The most common implant is the Amplatzer septal occluder which seems to be a highly effective and safe device. However, there are reports of complications associated with its implantation. We report a 9-year-old boy who presented with complete atrioventricular block after undergoing percutaneous closure of a large secundum ASD with an Amplatzer septal occluder. We treated the patient with oral prednisolone. The patient's atrioventricular conduction improved to second-degree Mobitz type 1 block on post-procedure day 24 and first-degree block on day 35. We conclude that patients with Amplatzer septal occluder-induced complete atrioventricular block generally have a good outcome, although it may take several weeks for improvement

Application of Head-up Tilt Table Testing in Children

Background/PurposeWe investigated the application of head-up tilt table testing (HUT) and management of neurocardiogenic syncope (NCS) in children, as pediatric studies are limited.MethodsSeventy-nine patients (ages 6-18 years) underwent HUT for evaluation of syncope. Patient triggers and premonitory symptoms allowed the clinical diagnosis of NCS or non-NCS. Results were divided into four hemodynamic types (1, 2A, 2B, and 3) according to patient response to HUT.ResultsNCS occurred in 65 patients and non-NCS in 14 patients. Isoproterenol infusion significantly increased the sensitivity of the test (from 28% to 45%) and was associated with a slight decrease in the specificity (from 93% to 86%). Subjects in the type 1 group accounted for the majority of responses to the test (69%). There were no complications associated with the test. At follow-up (16.6 ± 9.3 months), the overall recurrence rate was 30.8% but NCS was less severe in most patients. The recurrence rate was similar for patients with a positive or negative HUT and for both pharmacologically and non-pharmacologically treated patients.ConclusionHUT can be safely performed with a high specificity in children, with the sensitivity of HUT improved by isoproterenol. Therefore, a positive response to treatment is reassuring to the physician and family. NCS is generally a self-limited condition despite a high recurrence rate

Effects of vitamin D on inflammatory and oxidative stress responses of human bronchial epithelial cells exposed to particulate matter

PEP was a Wellcome Trust Clinical Research Training Fellow and this research was supported by the Wellcome Trust (Grant 098882/Z/12/Z). This research was also supported by the National Institute for Health Research (NIHR) Clinical Research Facility at Guy’s & St Thomas’ NHS Foundation Trust and NIHR Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London

Charge Density Wave Order and Electronic Phase Transitions in a Dilute d‐Band Semiconductor

As one of the most fundamental physical phenomena, charge density wave (CDW) order predominantly occurs in metallic systems such as quasi-1D metals, doped cuprates, and transition metal dichalcogenides, where it is well understood in terms of Fermi surface nesting and electron-phonon coupling mechanisms. On the other hand, CDW phenomena in semiconducting systems, particularly at the low carrier concentration limit, are less common and feature intricate characteristics, which often necessitate the exploration of novel mechanisms, such as electron-hole coupling or Mott physics, to explain. In this study, an approach combining electrical transport, synchrotron X-ray diffraction, and density-functional theory calculations is used to investigate CDW order and a series of hysteretic phase transitions in a dilute d-band semiconductor, BaTiS3 . These experimental and theoretical findings suggest that the observed CDW order and phase transitions in BaTiS3 may be attributed to both electron-phonon coupling and non-negligible electron-electron interactions in the system. This work highlights BaTiS3 as a unique platform to explore CDW physics and novel electronic phases in the dilute filling limit and opens new opportunities for developing novel electronic devices

Unconventional Charge-density-wave Order in a Dilute d-band Semiconductor

Electron-lattice coupling effects in low dimensional materials give rise to charge density wave (CDW) order and phase transitions. These phenomena are critical ingredients for superconductivity and predominantly occur in metallic model systems such as doped cuprates, transition metal dichalcogenides, and more recently, in Kagome lattice materials. However, CDW in semiconducting systems, specifically at the limit of low carrier concentration region, is uncommon. Here, we combine electrical transport, synchrotron X-ray diffraction and optical spectroscopy to discover CDW order in a quasi-one-dimensional (1D), dilute d-band semiconductor, BaTiS3, which suggests the existence of strong electron-phonon coupling. The CDW state further undergoes an unusual transition featuring a sharp increase in carrier mobility. Our work establishes BaTiS3 as a unique platform to study the CDW physics in the dilute filling limit to explore novel electronic phases

Experimental Study of Demolding Properties on Stereolithography Tooling

Direct tooling using stereolithography (SL

EFFECTS OF INTERFACE SLIP ON FLOW SHEAR STRESS BETWEEN DIFFERENT MATERIALS

Interfacial instability is an unsteady-state process in which the interface located between layers varies locally in a transient manner. This instability develops in the co-extrusion mold, and can be correlated with a critical interfacial shear stress for a particular polymer. In this work, a multilayer film co-extrusion experiment was conducted to measure the flow pressure drops on the mold wall along the flow to evaluate the flow shear stresses. Two pressure sensors were set sequentially on the mold wall along the flow direction for measuring the flow pressure drops. Pressure drops in the flow would be used to calculate flow shear stress. Variations of shear stress are then used to analyze interface slipping occur in the multilayer film. Two combinations of Polycarbonate (PC) / Polymethylmethacrylate (PMMA) and Polypropylene (PP) / Polycaprolactam (PA) were used as the experimental materials. Extrusion rate was experimentally increased to raise the pressure within the flow. According to the experiment results, when shear stress reaches a certain threshold, a large number of interfaces cause interfacial slip, which leads to a decline in shear stress. Increasing the number of interfaces increases interfacial slip. Moreover, PP/PA co-extruded film is more likely to cause slippage than PC/PMMA co-extruded film, because of its poor binding force between PP/PA interfaces

Restrictive Cardiomyopathy in a Child

Restrictive cardiomyopathy in young children is rare and carries a poor prognosis. We report an 18-month-old girl with poor feeding and abdominal distension. Except for hepatomegaly, no other gastrointestinal abnormalities were found. She had normalsized ventricles but biatrial enlargement. Echocardiography demonstrated normal systolic but impaired diastolic function. Cardiac catheterization revealed a characteristic dip-and-plateau configuration of the right ventricular pressure tracing. The diagnosis turned out to be typical restrictive cardiomyopathy. The patient was maintained on aspirin while awaiting cardiac transplant