Flexible bronchoscopy in children: Utility and complications

AbstractBackground and objectivesThe flexible bronchoscope has become widely used by pediatric pulmonologists as a diagnostic and therapeutic tool. Nevertheless, there are several gaps in our knowledge to help refine its use and reduce its complications. In this study, we aimed to evaluate the utility and complications of pediatric bronchoscopy.Design and settingWe conducted a retrospective review of bronchoscopy cases between March 2006 and April 2015 at a tertiary care medical center (King Fahad Medical City). One-hundred forty nine patients were studied.Patients and methodsWe evaluated how bronchoscopy contributed to the patients' diagnosis, assessed the accuracy of bronchoalveolar lavage white blood cell count (BAL WBC) to differentiate between infectious and non-infectious conditions, assessed the ability of clinical factors to predict high risk of desaturation during bronchoscopy, and finally summarized the reported procedural complications.ResultsWe found pediatric bronchoscopy was a crucial diagnostic (confirming, ruling out, and discovering unexpected diagnosis) and therapeutic tool. The accuracy of BAL WBC counts is poor (AUC (95% CI) = 0.609 (0.497–0.712)); however, using two cutoff values (≤10 WBCs (sensitivity = 84.44% and specificity = 29.27%) to rule out, and ≥400 WBCs (sensitivity = 33.33% and specificity 81.49%) to rule in infection) helped in early differentiation between infectious and non-infectious conditions. From the factors that we test, none we found predictive of desaturation. The most common procedural complication was desaturation (pooled incidence (95% CI) = 13 (8–19)%) followed by cough, mild airway bleeding, and spasm.ConclusionsFlexible bronchoscopy is an important and relatively safe diagnostic and therapeutic tool in pediatric medicine, and utilization of this service should be encouraged after a careful consideration of which patient needs this procedure and a rigorous estimate of its pros and cons

Influence of Monomer Systems on the Bond Strength Between Resin Composites and Polymerized Fiber-Reinforced Composite upon Aging

Purpose: This study examined the influence of different monomer systems on the tensile bond strength between a resin composite and a polymerized fiber-reinforced composite (FRC). The influence of the age (shelf-life) of the FRC prepreg (reinforcing fiber pre-impregnated with a resin system) before preparing the FRC substrate for the bonding test was also assessed.Materials and Methods: Semi-interpenetrating polymer network (semi-IPN)-based glass FRC prepregs were aged for various durations (1, 1.5, and 3 years) at 4 degrees C before being used to prepare FRC substrates via light polymerization. Four groups of aged prepregs were prepared through different treatments with: 1. no primer; 2. a dimethacrylate-based adhesive primer; 3. a universal primer; and 4. a specific composite primer. Subsequently, a resin composite luting cement was applied on the treated FRC substrates and cured with light. The water sorption of the FRC-composite specimens was determined. Then, the differences in the tensile bond strength were evaluated using ANOVA (p <= 0.05).Results: There were significant differences in the tensile bond strength between the composite cement and the FRC according to the primer used (p < 0.001), aging time (p < 0.001), and their interactive effect (p < 0.001).Conclusion: The monomers of the universal primer demonstrated the best ability to diffuse into the semi-IPN structure of the polymer matrix of FRC. This improved the interfacial bond strength between the composite cement and the FRC substrate

Solid-State NMR Spectroscopy:Towards Structural Insights into Starch-Based Materials in the Food Industry

Solid-state NMR is a nondestructive and noninvasive technique used to study the chemical structure and dynamics of starch-based materials and to bridge the gap between structure–function relationships and industrial applications. The study of crystallinity, chemical modification, product blending, molecular packing, amylose–amylopectin ratio, end chain motion, and solvent–matrix interactions is essential for tailoring starch product properties to various applications. This article aims to provide a comprehensive and critical review of research characterizing starch-based materials using solid-state NMR, and to briefly introduce the most advanced and promising NMR strategies and hardware designs used to overcome the sensitivity and resolution issues involved in structure–function relationships

Numerical evaluation of the breakout force of embedded objects in cohesive seafloor soils

ASCE, University of Colorad

Innovative Scheme for Evaluation of Soil Induced Stresses Using a Customized Two -point Gauss Formula

Abstract. This paper presents a systematic procedure in which the variation in induced stresses in soil layers is effectively dealt with using only two sublayers. A customized two -point Gauss quadrature formula was derived to evaluate induced stresses such that the weight factors for the derived formula were set equal to those of the two -point Gauss -Legendre formula. However, the base points were obtained by dividing the compressible layer into two sublayers whose thicknesses were determined such that their middle points are the base points for the derived formula. The thickness of the two sublayers was expressed in terms of a factor called the sublayering ratio. Expressions for this ratio were derived for different types of loads and loaded areas, and its values were presented in a series of normalized, non -dimensional charts. Numerical examples were included to illustrate the use of the developed charts for obtaining the value of the sublayering ratio, and the application of the derived formula in settlement computations. Keywords: Soil settlements, Sublayering ratio, Induced stresses, Gauss quadrature, Numerical method