Air Trapping Research Articles

Pore doublet micromodel experiments of evaporation influence on pre-event water entrapment and pre-event and event water interaction

The stable isotopic signature of xylem water differs from those of rainfall and river water. Without considering the water exchange through the vapor phase, this phenomenon implies that when the event water (new water) infiltrates the soil, a part of the pre-event water (old water) is isolated. The isolation and immobilization of old water are suspected because of the low matrix potential. Because evaporation is the main process that can reduce the matrix potential after quick gravitational drainage, we conjectured that after evaporation, the old water hides in small pores and increases the likelihood of air entrapment, which separates the new and old water. To examine and visualize the potential effect of evaporation on the interactions between old and new water, we performed a series of wetting–drainage–evaporation–wetting experiments within pore doublet micromodels (PDMs). The experimental results showed that air bubbles are trapped when the menisci of the residual liquid are sufficiently far from the inlet and outlet of the PDM. Evaporation can increase these distances, resulting in the formation of larger air bubbles. The air bubble trapped upstream prevents the invading liquid from quickly flushing the original residual liquid out of the PDM. Nevertheless, the invading wetting liquid is still able to bypass the trapped air bubbles and mix with the residual wetting phase via corner flow. In addition, the remobilization of the upstream bubble enhances the process of removing the old trapped liquid.

Risk factors for poorer respiratory outcomes in adolescents and young adults born preterm

RationaleThe respiratory outcomes for adult survivors of preterm birth in the postsurfactant era are wide-ranging with prognostic factors, especially those encountered after the neonatal period, poorly understood.ObjectivesTo obtain comprehensive ‘peak’...

Comparison of mild physiological effects of surgical masks and N95 respirators over 60 min at rest.

Dead-space-associated rebreathing of expired air and heat trapping with use of surgical masks and N95 respirators may underlie anecdotal reports of adverse symptoms associated with medical face barriers. Limited data exist directly comparing the physiological effects of masks and respirators at rest. We assessed the short-term physiological effects of both barrier types over 60 min at rest, including face microclimate temperature, end-tidal gases, and venous blood acid-base variables. We recruited 34 participants into two trials: surgical masks (n = 17) and N95 respirators (n = 17). In a seated position, participants underwent a 10-min baseline without a barrier and then wore a standardized surgical mask or dome-shaped N95 respirator for 60 min, followed by a 10-min washout. We instrumented healthy human participants with a peripheral pulse oximeter ([Formula: see text]) and a nasal cannula connected to a dual gas analyzer for measurement of the pressure of end-tidal [Formula: see text] and [Formula: see text], with an associated temperature probe for face microclimate temperature. Venous (v) blood samples were obtained at baseline and following 60-min mask/respirator wearing to assess [Formula: see text], [HCO3-]v and pHv. Compared with baseline during/following 60 min, temperature, [Formula: see text], [Formula: see text], and [HCO3-]v were mildly but significantly higher, and [Formula: see text] and [Formula: see text] were significantly lower, but [Formula: see text] was unaffected. The magnitude of effects was similar between barrier types. Temperature and [Formula: see text] returned to baseline levels within 1-2 min following removal of the barrier. These mild physiological effects may underlie reports of qualitative symptoms while wearing masks or respirators. However, the magnitudes were mild, not physiologically relevant and reversed immediately with the removal of the barrier.NEW & NOTEWORTHY Anecdotal reports suggest mild physiological effects of wearing surgical masks and/or N95 respirators, including heat trapping and rebreathing of expired air. There are limited data directly comparing the physiological effects of wearing medical barriers at rest. We found that the time course and magnitude of changes to face microclimate temperature, end-tidal gases, and venous blood gases and acid-base variables were mild in magnitude, not physiologically relevant, equivalent between barrier types, and immediately reversible on removal.

Water entry of cups and disks

It is known that the water entry of a body with a recessed, cupped nose can suppress the splash and air cavity typically observed for solid body entry (Mathai, Govardhan & Arakeri, Appl. Phys. Lett., vol. 106, 2015, 064101). However, the interplay between the captive gas in the cup, the cavity and the splash is quite subtle and has not been thoroughly explored. Here we study the cavity and splash dynamics associated with the vertical water entry of cups and find a variety of regimes over a range of Weber numbers ( $We_D$ ) and dimensionless cup depths. Our parameter space spans a transition between slow-developing cavities with long closure times (low $We_D$ ) to fast-sealing cavities (high $We_D$ ). An important dynamic event is the evacuation of trapped gas from within the cup, which drives the ensuing cavity and splash behaviour. Through modelling, we predict the conditions for which the evacuating gas inflates a cavity that opens to the atmosphere versus inflating a submerged cavity that suppresses air entrainment from above the surface. We also compare our cup water entry findings to the impact phenomena observed for flat disks, which entrap gas on the front surface similar to cups. In doing so, we reveal the sensitivity of disk splash and cavity behaviour to impact angle, and show that disks share a common regime with cups, in which a thin splash quickly seals on the body. We deduce the mechanisms by which increasing cup depth delays the cavity seal time in this regime. These findings reveal that cups may in fact promote or suppress cavity growth, depending on the cup depth and impact conditions.

Squeeze Film Effect in Surface Micromachined Nano Ultrasonic Sensor for Different Diaphragm Displacement Profiles

In the present paper, we have analytically explored the small variations of the local pressure in the trapped air film of both sides of the clamped circular capacitive micromachined ultrasonic transducer (CMUT), which consists of a thin movable membrane of silicon nitride (Si3N4). This time-independent pressure profile has been investigated thoroughly by solving the associated linear Reynold’s equation in the framework of three analytical models, viz. membrane model, plate model, and non-local plate model. The solution involves Bessel functions of the first kind. The Landau–Lifschitz fringing technique has been assimilated to engrave the edge effects in estimation of the capacitance of CMUT, which should be considered in the micrometer or lesser dimension. To divulge the dimension-based efficacy of the considered analytical models, various statistical methods have been employed. Our use of contour plots of absolute quadratic deviation revealed a very satisfactory solution in this direction. Though the analytical expression of the pressure profile is very cumbersome in various models, the analysis of these outputs exhibits that the pressure profile follows the displacement profile in all the cases indicating no viscous damping. A finite element model (FEM) has been used to validate the systematic analyses of displacement profiles for several radii and thicknesses of the CMUT’s diaphragm. The FEM result is further corroborated by published experimental results bearing excellent outcome.

Rendimiento clínico de espirometría y oscilometría respiratoria para predecir crisis graves en escolares con asma

ObjectiveTo determine the performance of spirometry and respiratory oscillometry (RO) in the prediction of severe asthma exacerbations (SAEs) in children. MethodsIn a prospective study, 148 children (age 6–14 years) with asthma were assessed with RO, spirometry and a bronchodilator test. Based on the findings of spirometry and the bronchodilator test, they were classified into 3 phenotypes: air trapping (AT), airflow limitation (AL) and normal. Twelve weeks later, they were re-evaluated in relation to the occurrence of SAEs. We analysed the performance of RO, spirometry and AT/AL phenotypes for prediction of SAEs by means of positive and negative likelihood ratios (LR+/LR–), ROC curves with the corresponding areas under the curve and a multivariate analysis adjusted for potential confounders. ResultsDuring the followup, 7.4% of patients had SAEs, and there were differences between phenotypes (normal, 2.4%; AL, 17.9%; AT, 22.2%, P=.005). The best area under the curve corresponded to the forced expiratory flow between 25% and 75% of vital capacity (FEF25–75): 0.787; 95% confidence interval, 0.600-0.973. Other significant areas under the curve were those for the reactance area (AX), forced expiratory volume in the first second (FEV1), the post- bronchodilator change in forced vital capacity (FVC), and the FEV1/FVC ratio. All of the variables had a low sensitivity for prediction of SAEs. The AT phenotype had the best specificity (93.8%; 95% confidence interval, 87.9-97.0), but LR+ and LR– were both significant only for the FEF25–75. In the multivariate analysis, only some spirometry parameters were significative for prediction of SAEs (AT phenotype, FEF25–75 and FEV1/FVC). ConclusionsSpirometry performed better than RO for prediction of SAEs in the medium term in schoolchildren with asthma.

Characterization and Superhydrophobic Anticorrosive Coating of AA-7475/ZrO2/Polymer Nanocomposites

An AA-7475 is coated with superhydrophobic (SH) polymer nanocomposites (PNCs), emphasizing the coating’s manufacturing, characterization, and anticorrosive qualities. Coating AA-7475 alloy with polyvinyl chloride (PVC), copper stearate (CS), and zirconium oxide (ZrO2) nanoparticles produces the desired superhydrophobic. Using an X-ray diffractometer, field-emission scanning electron microscopy, Fourier-transform infrared spectrometer, ZrO2 nanoparticles, CS, and PVC PNCs are analyzed structurally and molecularly. The atomic force microscope picture was analyzed to determine how the surface roughness affected the SH behavior reached by changing the weight percentage of ZrO2 nanoparticles from 0.6 to 3.0 wt%. PNC-5 with 3.0 wt% ZrO2 nanoparticles is used as resistance to corrosion coating for AA-7475 due to its water contact angle of 154°. In a 3.5% NaCl solution, uncoated and PNC-5-coated AA-7475 are examined using potentiodynamic polarization and electrochemical spectroscopy. PNC-5 coating reduces AA-7475 corrosion rate from 23.75 to 0.2253 mpy. In this study, we use polarization resistance, corrosion resistance efficiency, double layer capacitance, corrosion current density, and charge transfer resistance to demonstrate that the SH surface air trapping phenomena are responsible for effective corrosion resistance.

A Vexing Problem of Air Trapping in the Trima Accel During Plateletpheresis Procedure: Reflecting Our Experience in Troubleshooting.

Troubleshooting for any fault of apheresis equipment or kit is hardly addressed. Here, we report a unique problem of air trapping in a kit at two different positions leading to failure of the plateletpheresis procedure. Two plateletpheresis procedures were aborted due to "Access pressure low", though the needle position was absolutely perfect. In the third event, platelet yield was not increasing even after 30 minutes from the time of initiation. It was completed after stopping the centrifuge pump which could have displaced the air bubble from the collection port. The root cause for these events was analyzed in consultation with the apheresis technical expert and "air block" was found to be the cause. Air block can also result in a "low access pressure" alarm despite improper phlebotomy being the common cause. Perfect kit loading, checking of tubing defects prior to loading, and comparative analysis of troubleshooting to have adequate knowledge are essential tools for the smooth functioning of apheresis.

Effectiveness of T2 biologics in patients with common variable immune deficiency and allergic respiratory disease

IntroductionMany patients with common variable immune deficiency (CVID) have a history suggestive of allergic respiratory disease including chronic rhinosinusitis (CRS) and asthma. The underlying immunologic defect, the presence of comorbid conditions such as bronchiectasis or interstitial lung disease, and recurrent infections may make the diagnosis of these conditions difficult. T2 biologics targeting allergic inflammatory pathways are now the standard of care for severe persistent asthma and CRS with nasal polyposis (CRSwNP). The efficacy of these agents in patients with CVID is unknown. MethodsWe performed a retrospective analysis of patients with CVID at a single academic medical center and identified those who had ever been prescribed a T2 biologic. ResultsWe identified 8 patients with CVID who had ever been prescribed T2 biologics: 6 patients with severe persistent asthma and 2 patients with CRSwNP. All patients had CVID without inflammatory complications with therapeutic IgG levels on immune globulin replacement therapy. Comorbid bronchiectasis was identified in 3 patients and no patients had GLILD. Two patients were taking omalizumab, two on mepolizumab, 1 on benralizumab, and 1 on dupilumab for severe persistent asthma and 2 on dupilumab for CRSwNP. Only 4 patients in this group (50%) had subjective improvement of symptoms and objective clinical benefit based on ability to wean off of corticosteroids and fewer exacerbations per year. Only 1 of these patients had objective improvement in FEV1 by >200mL. Neither of the 2 patients treated with dupilumab for CRswNP reported improvement and the biologic was discontinued. Of the 2 patients with asthma who were found to have eosinophilia on bronchoalveolar fluid analysis, both of these patients had clinical improvement on eosinophil-targeted biologic therapy. All 3 patients who were tested were found to have elevated serum T2 cytokines including IL-4, but this did not predict response to therapy.Table 1(abstract: 191) Demographic and immunologic data of 8 patients with CVID on T2 biologiesAgeGenderT2 biologicIndicationBronchiectasisIncrease in FEV1 by >200mLClinical responseIgG (mg/dL)IgA (mg/dL)IgM (mg/dL)IgE (kU/L)Absolute eosinophil count(K/μL)CD19B cell count (cells/μL)Th2 Cytokine PanelBAL Eosinophils%CT ThoraxBronchoscopy-Pathology82Fomalizumabsevere persistent asthmayesnono1551522923430049Not availableNot availableBasal abnormalitycharacterized by ground glass opacities (GGO), centrilobular nodularity with small focus of consolidation posterior right lower lobe (RLL). Additional focus of patchy groundglass posterior right lung (RL).Not available74Mmepolizumabsevere persistent asthmayesnoyes11681623141681600176Not available25Resolution of right upper lobe (RUL) apical nodule and branching tubular opacity. New clustered nodularity in the posterior RLL with faint GGO in the upper lobes. Moderate bronchial wall thickening, greatest in the lower lobes.Bronchial wall with smooth muscle hypertrophy. Lung parenchyma without evidence of inflammation, fibrosis, or malignancy.57Fomalizumabsevere persistent asthmanonoyes89725221687100103Not available0Diffuse bronchial dilation without bronchial wall thickening. Mild patchy air trapping.Largely denuded and edematous bronchial wall with minima] chronic inflammation, focal subepithelial elastosis, focal expansion of the subbasal lamina, mild increase in mucous secretion.37Fdupilumabchronic rhinosinusitis with nasal Polyposisnonot applicableno787<10<20<2100187elevated IL-4, IL-6Not availableResolved patchy GGO with exception of a new tiny focus of GGO in the basal RLL. Stable mild diffuse bronchial wall thickening.Not available73Fbenralizumabsevere persistentnoyesyes84635<20<2100179Not available4Mild to moderate airway inflammation and diffuse air-trapping. Minimal left basilar linear atelectasis/scarring is new. TracheobronchomalaciaBronchial wall with moderate chronic inflammation and eosionphils (peak 12/hpf), thickened subbasal lamina, mild smooth muscle hypertrophy.43Fdupilumabsevere persistent asthmanonot availableyes12614313556.5056elevated IL-4, IL-5, IL-6Not availableBenign right oblique fissure. 2 small nodules.Not available56Fdupilumabyesnot applicableno95476602.625027Not available1chronic rhinosinusitis with nasal polyposisMultiple new areas of peribronchovascular consolidation and confluent GGO. Widespread tree-inbud nodularity. Mild cylindricalbronchiectasis. Dilated main pulmonary trunk.Bronchial wall with moderate chronic inflammation and scattered eosinophils (6/hpf), thickened subbasal lamina. No granulomas. Right lung bronchial wall with moderate chronic inflammation. Lung parenchyma with airway centered mild interstitial chronic inflammation49 Fmepolizumabsevere persistent asthmanonono166845189510049Not available0Mild bronchial wall thickening and scattered air trapping. Patchy GGO in the left upper lobe with minimal involvement of the lower lobes. Dynamic expiratory images demonstrates evidence of tracheobronchomalacia.Bronchial wall with patchy mild to moderate chronic inflammation with rare neutrophils and eosinophils. Mild smooth muscle hypertrophy. Patchy squamous metaplasia and respiratory bronchiolitis in the left lung.*Clinical response is measured by reduction in exacerbations and/or ability to wean off of corticosteroids for individuals with severe asthma and is measured by improvement in sinonasal symptoms and reduced nasal polypoid burden for CRSwNP. [Display omitted] [Display omitted] ConclusionPatients with CVID may benefit from more direct sampling of nasal mucosal and bronchial secretions (sputum, bronchoalveolar lavage) to determine the potential benefit from T2 biologics in severe allergic respiratory disease. Prospective analyses in larger cohorts following objective indices of improvement as well as changes in serum and mucosal biomarkers are necessary.

SonoRotor: An Acoustic Rotational Robotic Platform for Zebrafish Embryos and Larvae

Rotation manipulation is an essential component of biological microscopy and can become integral to multidisciplinary research and applications. On-chip rotation of microobjects with spherical shapes like biological cells and model organisms has been demonstrated based on advanced microfluidic techniques. To date, however, biocompatible, easy-to-fabricate, easy-to-operate, and controlled rotation of small animal models with slender bodies remains a challenge. Here, we present SonoRotor, a miniaturized acoustic rotation platform for animal models using a single elongated acoustically activated air bubble. In the presence of an acoustic field, the trapped elongated air bubble oscillates and induces a polarized vortex in the surrounding liquid. Zebrafish embryos (spherical) and larvae (slender), typically larger than hundreds of micrometers, become trapped near the oscillating bubble and undergo a controllable, high-speed, and stable out-of-plane rotation. By controlling the voltage applied to our device, we can adjust the rotation speed of the zebrafish. The developed acoustic rotation manipulation platform is simple, cost-effective, allows multiview imaging, high-throughput operation, and can be combined with downstream analytical techniques to perform a variety of biological micromanipulation on small animal models.

The Impact of Relative Permeability Hysteresis on CO2 Sequestration in Saline Aquifer

This work analyzed the amount of capillary-trapped CO2 for maximum residual gas saturation due to relative permeability hysteresis. Upward migration of CO2 is unwanted because it increases the risk of CO2 migration from storage sites to the surface. One way to mitigate CO2 leakage risk is to reduce the vertical CO2 migration to improved storage capacity and containment security. A compositional simulator (CMG-GEM) was used to simulate the flow of two components (CO2 and H2 O). A fluid model was built with the PR 78 EOS using WINPROP. A base case model without relative permeability hysteresis was simulated and compared with the case with relative permeability hysteresis. The amount of CO2 trapped, and CO2 saturation distribution were analyzed for maximum trapped gas saturation of 0.3, 0.4 and 0.5. Results shows an increase in the amount of CO2 trapped as the maximum residual gas saturation was increased from 0.3 to 0.4 and 0.5 with a value of 16560128mol for the base case study, 49041744mol, 59502924mol and 67286728mol respectively for maximum residual gas saturation due to relative permeability hysteresis of 0.3, 0.4 and 0.5 respectively. Very little accumulation of CO2 occurs when the maximum trapped gas saturation due to relative permeability hysteresis was set at 0.5. Result reveals that after 200 years, almost all the CO2 was trapped in the formation. Therefore, the imbibition cycle at the trailing end of the CO2 plume should be considered as accounting for hysteresis effects has led to a spread-out distrib

Using Mitral Annular Plane Systolic Excursion (MAPSE) and Tissue Doppler Imaging Systolic Velocity (TDIS’) As Surrogates of Left Ventricular Systolic Function

Purpose: Echocardiography has become a useful method for assessing structural diseases of the heart. MAPSE and TDI S’ have also been shown to be reproducible assessments of longitudinal heart changes as LVEF is ineffective in cases of sub-optimal echocardiographic imagery caused by artefacts or air trapping.&#x0D; Methodology: One hundred patients referred for echocardiography at the cardiac laboratory of DELSUTH, Oghara, Nigeria was recruited for the study. All patients had trans-thoracic echocardiography done with M-Mode, 2D and Spectral Doppler and Tissue Doppler echocardiographic images acquired. Data obtained was analyzed using IBM-SPSS version 22. A p-value of ≤0.05 was considered significant for all comparisons.&#x0D; Findings: Hypertension was the commonest indication for an echocardiogram. The prevalence of abnormal left ventricular function was 13%, 24% and 28% as determined using LVEF, TDI S’ and MAPSE. MAPSE had a higher specificity than TDI S’ with statistically significant correlations found between TDI S’ (p&lt;0.001); MAPSE (p=0.032) and LVEF. Multiple linear and binomial logistic regression analysis showed significant relationships (beta=0.423; p &lt;0.001) and odd ratios [OR(CI) = 10.80(2.56- 49.07)] respectively between TDI S’ and LVEF.&#x0D; Unique Contribution to Theory, Policy and Practice: MAPSE’s specificity allows for diagnosis of longitudinal heart functional changes even in cases where the LVEF may be within normal limits. A combination of both MAPSE and TDI S’ offer a greater prognostic significance. The correlation between MAPSE and TDI S’ were good. Thus, MAPSE and TDI S’ can serve as surrogates for LVEF in assessing left ventricular systolic function and prognosticating cardiac disease

Canine-inspired Unidirectional Flows for Improving Memory Effects in Machine Olfaction.

A dog's nose differs from a human's in that air does not change direction but flows in a unidirectional path from inlet to outlet. Previous simulations showed that unidirectional flow through a dog's complex nasal passageways creates stagnant zones of trapped air. We hypothesize that these zones give the dog a "physical memory," which it may use to compare recent odors to past ones. In this study, we conducted experiments with our previously built Gaseous Recognition Oscillatory Machine Integrating Technology (GROMIT) and performed corresponding simulations in two dimensions. We compared three settings: a control setting that mimics the bidirectional flow of the human nose; a short-circuit setting where odors exit before reaching the sensors; and a unidirectional configuration using a dedicated inlet and outlet that mimics the dog's nose. After exposure to odors, the sensors in the unidirectional setting showed the slowest return to their baseline level, indicative of memory effects. Simulations showed that both short-circuit and unidirectional flows created trapped recirculation zones, which slowed the release of odors from the chamber. In the future, memory effects such as the ones found here may improve the sensitivity and utility of electronic noses.

The Effects of Endogenous Cannabinoids on the Mammalian Respiratory System: A Scoping Review of Cyclooxygenase-Dependent Pathways.

Introduction: The endogenous cannabinoid (endocannabinoid) system is an emerging target for the treatment of chronic inflammatory disease with the potential to advance treatment for many respiratory illnesses. The varied effects of endocannabinoids across tissue types makes it imperative that we explore their physiologic impact within unique tissue targets. The aim of this scoping review is to explore the impact of endocannabinoid activity on eicosanoid production as a measure of human airway inflammation. Methods: A scoping literature review was conducted according to PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) guidelines. Search strategies using MeSH terms related to cannabinoids, eicosanoids, cyclooxygenase (COX), and the respiratory system were used to query Medline, Embase, Cochrane, CINAHL, Web of Science, and Biosis Previews in December 2021. Only studies that investigated the relationship between endocannabinoids and the eicosanoid system in mammalian respiratory tissue after 1992 were included. Results: Sixteen studies were incorporated in the final qualitative review. Endocannabinoid activation increases COX-2 expression, potentially through ceramide-dependent or p38 and p42/44 Mitogen-Activated Protein Kinase pathways and is associated with a concentration-dependent increase in prostaglandin (PG)E2. Inhibitors of endocannabinoid hydrolysis found either an increase or no change in levels of PGE2 and PGD2 and decreased levels of leukotriene (LT)B4, PGI2, and thromboxane A2 (TXA2). Endocannabinoids increase bronchial epithelial cell permeability and have vasorelaxant effects in human pulmonary arteries and cause contraction of bronchi and decreased gas trapping in guinea pigs. Inhibitors of endocannabinoid hydrolysis were found to have anti-inflammatory effects on pulmonary tissue and are primarily mediated by COX-2 and activation of eicosanoid receptors. Direct agonism of endocannabinoid receptors appears to play a minor role. Conclusion: The endocannabinoid system has diverse effects on the mammalian airway. While endocannabinoid-derived PGs can have anti-inflammatory effects, endocannabinoids also produce proinflammatory conditions, such as increased epithelial permeability and bronchial contraction. These conflicting findings suggest that endocannabinoids produce a variety of effects depending on their local metabolism and receptor agonism. Elucidation of the complex interplay between the endocannabinoid and eicosanoid pathways is key to leveraging the endocannabinoid system as a potential therapeutic target for human airway disease.

First report of post-vomiting subcutaneous peri-lacrimal drainage system emphysema

Subcutaneous emphysema is defined as a trapped air in tissues under the skin. This entity most often occurs in the chest wall and neck but can infrequently happen in other parts of the body like the orbital area [1]. The main mechanism of subcutaneous emphysema is the traumatic damage of the anatomical air-filled cavities or canals. Most of the rare, reported cases of orbital and periorbital emphysema were described in adults as complications of several types of traumas, including direct trauma, recent or previous surgery [2,3], barotrauma secondary to non-invasive ventilation, such as continuous positive airway pressure therapy [4], and even post forceful nose-blowing [5]. In this report, we described the first reported case of post-vomiting subcutaneous emphysema surrounding the medial canthus of the right eye in a 10-year-old boy.

Inter-relationships among neutrophilic inflammation, air trapping and future exacerbation in COPD: an analysis of ECOPD study

BackgroundThe inter-relationships among neutrophilic airway inflammation, air trapping and future exacerbation in chronic obstructive pulmonary disease (COPD) remain unclear.ObjectiveTo evaluate the associations between sputum neutrophil proportions and future exacerbation in...

Orbital emphysema

Orbital emphysema (OE) is an uncommon, benign, and self-limiting condition that results from trapping of air in loose periorbital subcutaneous tissues. We report a series of five cases of OE, four post traumatic, and one after forceful nose blowing. They presented with acute periorbital swelling. The clinical diagnosis was confirmed on imaging promptly. They were counseled to keep a keen eye for any signs of deterioration and kept on close follow-up. Some key clinical and radiological clues which indicated a relatively low risk of deterioration were noted, so they were conservatively managed with cold compression, avoidance of nose blowing/sneezing, nasal decongestants, oral antibiotics, and anti-inflammatories. Complete resolution of symptoms occurred within 2–3 weeks. Timely diagnosis, thorough patient counseling, conservative management, close monitoring, and expedient surgical intervention on deterioration are keystones in OE management.

Insulation Materials Based on Recycled Feather Waste: A Review

Recently, the world has been moving towards reusing wastes in many industrial applications, such as buildings and automotive, to eliminate the environmental pollution impact due to increasing waste worldwide. Besides, waste reuse also leads to cost savings and improves sustainability. Therefore, this short review aims to present and discuss the recently used methods of utilizing feather waste as sustainable and renewable insulation instead of traditional petroleum-derived materials. The father's low thermal conductivity ranges from 0.024 W/(m. K) to 0.034 W/(m. K), and it's chemical composition and microstructure effectively trap air and produce a good barrier. So, feather waste fibers can be used as an effective thermal and acoustic insulation material with the same or better performance than commercially available products. However, several significant barriers and limitations associated with the manufacturing process of feathers insulations were identified in this review. These limitations make the commercial development of insulation materials based on feather waste a challenge. They need to be appropriately addressed to realize the potential of feather waste as a reliable insulation material.

Failure Mode and Effect Analysis (FMEA) of a Taurus 60 Gas Turbine Power Plant System (GTPPS), in Mowe, Nigeria

Failure Mode and Effect Analysis (FMEA) is an approach used for maintenance system reliability analysis. FMEA is applied to the Taurus 60 Gas Turbine Power Plant System (GTPPS). The unexpected failures with the associated maintenance costs are major problems in most power plants. In this study, critical components of the Taurus 60 gas turbine power plant were identified. Twenty-five sub-assemblies were identified and the probable failure modes of the main sub-assemblies. Failure analysis and the Risk Priority Numbers (RPN) of the critical sub-assemblies were determined using failure modes and effect analysis method. Failure analysis and the Risk Priority Numbers (RPN) of the critical sub-assemblies were determined using failure modes and effect analysis method. Based on criticality analysis, six (6) critical sub-assemblies were identified. These are fuel gas supply, air filter package, air trap package, gearbox, compressor rotor assembly and fuel injector with criticality numbers 12.5, 20.83, 20.83, 20.83, 16.67 and 20.83 respectively. The failure analysis for these critical sub-assemblies specified the failure modes, failure effects, maintenance tasks, frequency of inspection and strategies. The ranges of the Risk Priority Number (RPN) for the components of fuel gas supply, air filter package, air trap package, gearbox, compressor rotor assembly and fuel injector were 54-126, 60-90, 75-90, 72-84, 36-112 and 90-120 respectively. The critical sub-assemblies should be given close attention in terms of monitoring, routine checks which can be monitored using prepared checklists. The semi- critical and non- critical assemblies should not be neglected either.

Retrocardiac Pneumomediastinum: Description of an Unusual Case and Review of Literature

Retrocardiac pneumomediastinum (RP) is the consequence of air trapping in the inferior and posterior mediastinum. It is characterized by the presence of a right or left para-sagittal infrahilar oval or pyramidal air collection on a chest X-ray. It is usually detected in neonates because of alveolar rupture after invasive ventilation or invasive manoeuvres applied on airways or the digestive tract. A healthy child came to the emergency department (ED) for acute respiratory failure due to viral bronchiolitis when he was 2 months old. Because of his clinical condition, he underwent helmet continuous positive airway pressure (HCPAP). When the condition allowed, he was discharged and sent home. He was re-admitted into the hospital for asthmatic bronchitis 3 months later. A frontal chest X-ray taken during the second hospitalization showed an oval-shaped retrocardiac air lucency not previously detected. Differential diagnosis including digestive and lung malformations was made. Finally, the diagnosis of RP was made. We report an unusual case of retrocardiac pneumomediastinum in a 5-month-old male infant after the application of continuous positive pressure via a helmet. RP presentation after the administration of non-invasive ventilatory support beyond the neonatal age is unusual. Although surgical drainage is curative, conservative treatment can be considered in hemodynamically stable patients.