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Recent advancements in asthma management include non-invasive methodologies such as sputum analysis, exhaled breath condensate (EBC), and fractional exhaled nitric oxide (FeNO). These techniques offer a means to assess airway inflammation, a critical feature of asthma, without invasive procedures. Sputum analysis provides detailed insights into airway inflammation patterns and cellular composition, guiding personalized treatment strategies. EBC collection, reflecting bronchoalveolar lining fluid composition, provides a non-invasive window into airway physiology. FeNO emerges as a pivotal biomarker, offering insights into eosinophilic airway inflammation and aiding in asthma diagnosis, treatment monitoring, and the prediction of exacerbation risks. Despite inherent limitations, each method offers valuable tools for a more comprehensive assessment of asthma. Combining these techniques with traditional methods like spirometry may lead to more personalized treatment plans and improved patient outcomes. Future research is crucial to refine protocols, validate biomarkers, and establish comprehensive guidelines in order to enhance asthma management with tailored therapeutic strategies and improved patient outcomes. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease (COPD), as the third leading cause of death among adults, is a significant public health problem around the world. However, about 75% of smokers do not develop the disease despite the severe smoking burden. COPD is a heterogeneous disease, and several phenotypes, with differences in their clinical picture and response to treatment, have been distinguished. Metabolomic studies provide information on metabolic pathways, and therefore are a promising tool for understanding disease etiopathogenesis and the development of effective causal treatment. The aim of this systematic review was to analyze the metabolome of the respiratory epithelial lining fluid of patients with COPD, compared to healthy volunteers, refractory smokers, and subjects with other lung diseases. We included observational human studies. Sphingolipids, phosphatidylethanolamines, and sphingomyelins distinguished COPD from non-smokers; volatile organic compounds, lipids, and amino acids distinguished COPD from smokers without the disease. Five volatile organic compounds were correlated with eosinophilia and four were associated with a phenotype with frequent exacerbations. Fatty acids and ornithine metabolism were correlated with the severity of COPD. Metabolomics, by searching for biomarkers and distinguishing metabolic pathways, can allow us to understand the pathophysiology of COPD and the development of its phenotypes. [ABSTRACT FROM AUTHOR]

The problem of the formation and estimation of a thermoradiant and temperature field in ceramics Thermal- Environmental-Barrier Coatings (TBC/EBC) has been considered with complex heat transfer but under the influence of the penetrating intense radiant component. The authors proposed to analyze not only TBC but also EBC from the point of view of the optics of semitransparent scattering and absorbing media in the range of ~0.4–4 μm of external radiant action. This paradigm allows us to continue the study of ceramic fibers embedded in ceramic matrix CMCs (C/C, C/SiC, SiC/SiC) as a traditional class of opaque materials. However, at the same time, mullites, Al2O3/Al2O3 have been reviewed as a class of semitransparent elements for designing CMCs. The relevance of studying the effect of oriented fibers on the formation of thermoradiation and temperature fields in a semitransparent material was noted. Modeling the scattering asymmetry coefficient influence (scattering phase function) on the generation of the subsurface thermal radiation source was carried out. The methodology for calculating the thermoradiative field in a semitransparent medium (with relative absorption, scattering indexes, and scattering asymmetry coefficient) was used under a one-dimensional two-flux model as the first approximation for solving the radiative heat transfer equation. Calculations of temperature profiles in opaque and semitransparent ceramics were presented under heat load typical for the combustion chambers operating regime of diesel and gas turbine engines. [ABSTRACT FROM AUTHOR]

The process scale-up of fully oxide-based environmental barrier coatings (EBCs) on sintered SiC and chemical vapor infiltration (CVI) SiC/SiC ceramic matrix composite (CMC) sub-components was investigated using various slurry manufacturing processes (dip, spray, spin–dip). The performance of EBC-coated sub-components (SiC heating element, SiC/SiC ceramic matrix mini-composite, SiC airfoil, SiC/SiC CMC airfoil) was evaluated in steam oxidation and combustion rigs. Steam oxidation was conducted at 1427 °C in 90 vol.% H2O (g) + 10 vol.% O2 (g) with a 1 h hold at 1427 °C per cycle (1 h hot and 20 min cooling). For high-pressure combustion rig testing, the EBC surface temperature ranged between 1354 °C and 1538 °C with the temperature gradient through CMC + EBC ranging between 100 °C and 150 °C. Dip and spin–dip are non-line-of-sight processes, whereas spray is a line-of-sight process. The three processes, collectively, demonstrated the capability to manufacture slurry EBCs on sub-components with various shapes and sizes. There was no discernable disparity in the EBC steam oxidation performance between the coupons and sub-components in this study and coupons in a previous study. The dependence of steam oxidation rates on the substrate chemistry reported previously was confirmed. The steam oxidation rate of EBC-coated sintered SiC, compared with EBC-coated CVI CMC, was ~2 times and ~1.5 times higher after 100 h and 500 h, respectively, due to the boron sintering aid in sintered SiC. An EBC-coated CMC airfoil after 150 15-h-long cycles in a high-pressure combustion rig test showed only limited EBC spallation along the leading edge and more substantial spallation along the trailing edge, demonstrating the feasibility of an oxide-based bond coat to meet the extreme temperature requirements of next-generation EBCs. [ABSTRACT FROM AUTHOR]

To understand the failure mechanism or to predict the spallation life of environmental barrier coatings (EBC) on fiber reinforced ceramic matrix composites, the fracture strength of EBC and the process of the crack growth in EBC layers need to be experimentally determined under standard or simulated engine operating conditions. The current work considers a multi layered barium strontium aluminum silicate (BSAS)-based EBC-coated, melt infiltrated silicon carbide fiber reinforced silicon carbide matrix composite (MI SiC/SiC) specimen that was tensile tested at room temperature. Numerous tests were performed under tensile loading conditions, and the specimen was loaded until failure under pre-determined stress levels. The specimen was examined with optical microscopy, scanning electron microscopy (SEM), computed tomography (CT) scan, and digital image correlation (DIC) camera. Observation from the computed tomography scanning, the SEM, and the optical microscopy did not offer conclusive information concerning the cracks that spawned during the tests. However, inspection with the DIC camera offered some indication that cracks had developed and allowed their detection and the location of their initiation site. Thus, this study provides detailed discussion of the results obtained from the experimental investigation and the nondestructive evaluation (NDE), and it also includes assessment of the stress response predicted by analytical modeling and their impact on EBC durability and crack growth formation under complex loading settings. [ABSTRACT FROM AUTHOR]

Three pools of exhaled breath condensate (EBC) from non-smokers plus healthy smokers (NS + HS, n = 45); chronic obstructive pulmonary disease (COPD) without emphysema (COPD, n = 15) and subjects with pulmonary emphysema associated with α1-antitrypsin deficiency (AATD, n = 23) were used for an exploratory proteomic study aimed at generating fingerprints of these groups that can be used in future pathophysiological and perhaps even clinical research. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was the platform applied for this hypothesis-free investigation. Analysis of pooled specimens resulted in the production of a "fingerprint" made of 44 proteins for NS/HS; 17 for COPD and 15 for the group of AATD subjects. Several inflammatory cytokines (IL-1α, IL-1β, IL-2; IL-12, α and β subunits, IL-15, interferon α and γ, tumor necrosis factor α); Type I and II cytokeratins; two SP-A isoforms; Calgranulin A and B and a1-antitrypsin were detected and validated through the use of surface enhanced laser-desorption ionization mass spectrometry (SELDI-MS) and/or by Western blot (WB) analysis. These results are the prelude of quantitative studies aimed at identifying which of these proteins hold promise as identifiers of differences that could distinguish healthy subjects from patients. [ABSTRACT FROM AUTHOR]

(1) Background: L-arginine (L-ARG) and its metabolites are involved in some aspects of asthma pathogenesis (airway inflammation, oxidative stress, bronchial responsiveness, collagen deposition). Published data indicate that lungs are a critical organ for the regulation of L-ARG metabolism and that alterations in L-ARG metabolism may be significant for asthma. The aim of this study was to assess the levels of L-ARG and its metabolites in pediatric patients with asthma in serum and exhaled breath condensate (EBC) by mass spectrometric analysis and compare them with non-asthmatic children. (2) Methods: Sixty-five children (37 pediatric patients with bronchial asthma and 28 healthy control subjects) aged 6–17 participated in the study. All participants underwent a clinical visit, lung tests, allergy tests with common aeroallergens, and serum and EBC collection. The levels of biomarkers were determined in both serum and EBC. Analytical chromatography was conducted using an Acquity UPLC system equipped with a cooled autosampler and an Acquity HSS T3 column. Mass spectrometric analysis was conducted using the Xevo G2 QTOF MS with electrospray ionization (ESI) in positive ion mode. (3) Results: Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) levels in serum and EBC did not differ significantly in asthmatic children and healthy control subjects. We found no correlation between forced expiratory volume in one second (FEV1) and L-ARG and its metabolites, as well as between interleukin-4 (IL-4) serum level and L-ARG and its metabolites. Concentrations of ADMA, SDMA, citrulline (CIT), and ornithine (ORN) were higher in serum than EBC in asthmatics and non-asthmatics. By contrast, concentrations of dimethylarginine (DMA) were higher in EBC than serum. ADMA/L-ARG, SDMA/L-ARG, and DMA/L-ARG ratios were significantly higher in EBC than in serum in asthmatics and in non-asthmatics. (4) Conclusions: Serum and EBC concentrations of L-ARG and its metabolites were not an indicator of pediatric bronchial asthma in our study. [ABSTRACT FROM AUTHOR]

Inhaled ultrafine particle (UFP) content in exhaled breath condensate (EBC) was observed as an airway inflammatory marker and an indicator of exposure to particulate matter (PM). The exceptional decline in air pollution during the COVID-19 lockdown was an opportunity to evaluate the effect of environmental changes on UFP airway content. We collected EBC samples from 30 healthy subjects during the first lockdown due to COVID-19 in Israel (March-April 2020) and compared them to EBC samples retrieved during April-June 2016 from 25 other healthy subjects (controls) living in the same northern Israeli district. All participants underwent EBC collection and blood sampling. Ambient air pollutant levels were collected from the Israeli Ministry of Environmental Protection's online database. Data were acquired from the monitoring station closest to each subject's home address, and means were calculated for a duration of 1 month preceding EBC collection. UFP contents were measured in the EBC and blood samples by means of the NanoSight LM20 system. There was a dramatic reduction in NO, NO 2 , SO 2 , and O 3 levels during lockdown compared to a similar period in 2016 (by 61%, 26%, 50%, and 45%, respectively). The specific NO 2 levels were 8.3 ppb for the lockdown group and 11.2 ppb for the controls ( p = 0.01). The lockdown group had higher UFP concentrations in EBC and lower UFP concentrations in serum compared to controls (0.58 × 10 8 /mL and 4.3 × 10 8 /mL vs. 0.43 × 10 8 /mL and 6.7 × 10 8 /mL, p = 0.05 and p = 0.03, respectively). In this observational study, reduced levels of air pollution during the COVID-19 lockdown were reflected in increased levels of UFP airway contents. The suggested mechanism is that low airway inflammation levels during lockdown resulted in a decreased UFP translocation to serum. Further studies are needed to confirm this hypothesis.

Introduction: Lung cancer is the second most frequent malignancy worldwide, but its aetiology is still unclear. Inflammatory cytokines and Th cells, including Th17, are now emerging as being involved in NSCLC pathways, thus postulating a role of IL-17 in tumour angiogenesis by stimulating the vascular endothelial growth factor and the release of nitric oxide. Despite the fact that many biomarkers are used for chest malignancy diagnosis, data on FeNO levels and inflammatory cytokines in NSCLC are still few. Our study aimed to evaluate the relationship between pulmonary nitric oxide production and VEGF and Th17-related cytokines in the EBC of patients affected by early-stage NSCLC. Methods: FeNO measurement and lung function tests were performed in both patients affected by NCSLC and controls; EBC samples were also taken, and Th1 (IL-1, IL-6, IL-12, IFN-g, TNF-a), Th17 (IL-17, IL-23) and Th2 (IL-4, IL-5, IL-13) related cytokines were measured. Results: Th1 and Th17-related cytokines in EBC, except for IFN-gamma and TNF-alpha, were significantly higher in patients than in healthy controls, whereas no differences were seen for Th2-related cytokines. FeNO at the flow rate of 50 mL/s, JawNO and CalvNO levels were significantly higher in patients affected by NSCLC compared to controls. Significant correlations were found between FeNO 50 mL/s and IL-17, IL-1 and VEGF. JawNO levels positively correlated with IL-6, IL-17 and VEGF. No correlations were found between FeNO and Th2-related cytokines. Conclusion: This is the first report assessing a relationship between FeNO levels and Th17-related cytokines in the EBC of patients affected by early-stage NSCLC. IL-17, which could promote angiogenesis through the VEGF pathway, might be indirectly responsible for the increased lung production of NO in patients with NSCLC. [ABSTRACT FROM AUTHOR]

In recent years, black carbon (BC) has been gaining more attention due to the diversity of anthropogenic sources and the harmful effects on human health, environment, and climate. In this paper, for the first time in Poland, the results of long-term measurements of eBC concentrations (2009–2020) at the urban background station in Zabrze (southern Poland) are presented. A Multi-Angle Absorption Photometer (MAAP) was used, which enables the measurement of eBC concentration in fine particulate matter (PM2.5). The mean concentration of eBC over the 11-year period (3.82 μg·m−3) was higher compared to the values recorded at most European urban stations. Annual averaged eBC levels showed a downward trend and clear seasonal variations, which was caused mainly by changes in the intensity of anthropogenic emissions. The impact of meteorological parameters, in particular air temperature and wind speed, which determine the intensity of emissions and the conditions of pollutant dispersion, was not without significance. The work additionally attempts to assess the possible impact of remedial actions carried out in Zabrze over the last decade. The results showed that modernization in industry and heating and maintenance of green areas potentially had the most important impact on the decline in eBC concentrations. [ABSTRACT FROM AUTHOR]

The pathophysiology of asthma has been intensively studied, but its underlying mechanisms such as airway inflammation, control of airway tone, and bronchial reactivity are still not completely explained. There is an urgent need to implement novel, non-invasive diagnostic tools that can help to investigate local airway inflammation and connect the molecular pathways with the broad spectrum of clinical manifestations of asthma. The new biomarkers of different asthma endotypes could be used to confirm diagnosis, predict asthma exacerbations, or evaluate treatment response. In this paper, we briefly describe the characteristics of exhaled breath condensate (EBC) that is considered to be an interesting source of biomarkers of lung disorders. We look at the composition of EBC, some aspects of the collection procedure, the proposed biomarkers for asthma, and its clinical implications. We also indicate the limitations of the method and potential strategies to standardize the procedure of EBC collection and analytical methods. [ABSTRACT FROM AUTHOR]

The global increase in air travel will require commercial vehicles to be more efficient than ever before. Advanced turbine hot section materials are a key technology required to keep fuel consumption and emission to a minimum. Ceramic matrix composites (CMCs) are the most promising material to revolutionize turbine hot section materials because of their excellent high-temperature properties. Rapid surface recession due to volatilization by water vapor is the Achilles heel of CMCs. Environmental barrier coatings (EBCs), which protect CMCs from water vapor, is an enabling technology for CMCs. The first CMC component entered into service in 2016 in a commercial engine, and more CMC components are scheduled to follow within the next few years. One of the most difficult challenges to CMC components is EBC durability because failure of EBC leads to a rapid reduction in CMC component life. Novel EBC chemistries, creative EBC designs, and robust processes are required to meet EBC durability challenges. Engine-relevant testing, characterization, and lifting methods need to be developed to improve EBC reliability. The aim of this Special Issue is to present recent advances in EBC technology to address current EBC challenges. [ABSTRACT FROM AUTHOR]

Tri-layer Si/mullite/Yb2SiO5 environmental barrier coating (EBC) was prepared on the SiCf/SiC ceramic matrix composite (CMC) by plasma spray-physical vapor deposition (PS-PVD). The EBC samples were carried out with water vapor corrosion at 1300 °C for 200 h. After steam corrosion, Yb2SiO5 layer forms a gradient porous structure. This is mainly due to the inclusion of SiO2-rich layer which is precipitated from the gasification inside the coating and existing a small amount of Yb2O3 separately. During the corrosion process, water vapor infiltrates into the coating and reacts with the SiO2 and Yb2O3 to generate volatile substances. This forms a porous structure to make the coating brittle, resulting in mud cracks finally. In addition, the results show that the Yb2SiO5 can react with the water vapor at the coating surface, forming an Yb2Si2O7 top layer. [ABSTRACT FROM AUTHOR]

Turbine environments may degrade high temperature ceramics because of volatile hydroxide reaction products formed in water vapor. Accordingly, the volatility of transient TiO2 and steady-state Al2O3 scales formed on the oxidation-resistant Ti2AlC MAX phase ceramic was examined in 1300 °C high velocity (Mach 0.3, 100 m/s) and high pressure (6 atm, 25 m/s) burner rig tests (BRT). Unlike metals, the ceramic was stable at 1300 °C. Unlike SiC and Si3N4, neither burner test produced a weight loss, unless heavily pre-oxidized. Lower mass gains were produced in the BRT compared to furnace tests. The commonly observed initial, fast TiO2 transient scale was preferentially removed in hot burner gas (~10% water vapor). A lesser degree of gradual Al2O3 volatilization occurred, indicated by grain boundary porosity and crystallographic etching. Modified cubic-linear (growth-volatility) kinetics are suggested. Gas velocity and water vapor pressure play specific roles for each scale. Furthermore, a 7YSZ TBC on Ti2AlC survived for 500 h in the Mach 0.3 burner test at 1300 °C with no indication of volatility or spalling. [ABSTRACT FROM AUTHOR]

Background: Recently, epithelial alarmins have been shown to play important roles in non-allergen driven respiratory diseases like idiopathic pulmonary fibrosis (IPF). Little is known about the expression of the epithelial alarmins in IPF. Methods: This study aimed to prospectively examine interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) levels in the serum and exhaled breath condensate (EBC) in patients with IPF before and after one-year of antifibrotic treatment. A total of 82 volunteers, including 52 patients diagnosed with IPF that qualified for antifibrotic therapy as well as 30 controls, were examined. All study participants underwent baseline peripheral blood and EBC sampling. In 35 out of 52 IPF subjects, a follow-up sampling was performed after 12 months of antifibrotic treatment. Concentrations of alarmins in the serum and EBC were evaluated by means of ELISA. Results: Baseline TSLP concentrations were significantly elevated in patients with IPF compared to controls both in the serum (p < 0.05) and EBC (p < 0.0001). Baseline IL-25 and IL-33 serum and EBC levels did not differ significantly between IPF subjects and controls. Prospective analysis of changes in the epithelial alarmin levels showed significantly decreased IL-25 and TSLP EBC concentrations after 12 months of antifibrotic treatment (p < 0.05), which was observed in the subgroup of IPF patients treated with pirfenidone, but not in those treated with nintedanib. In stable patients with IPF over a study period (absolute forced vital capacity (FVC) % of predicted decline/year ≤ 5%, n = 25), a significant decrease in the EBC levels of both IL-25 and TSLP after 12 months of antifibrotic treatment was noted (p < 0.05), whereas, in progressor IPF patients (absolute FVC % of predicted decline/year > 5%, n = 10), a significant decrease was noted in the IL-25 EBC levels only (p < 0.05). Conclusions: Elevated TSLP levels in patients with IPF and their significant decrease in the lung compartment during antifibrotic therapy in stable patients with IPF, but not in progressors, support its significant contribution to pro-fibrotic type 2 immune responses in IPF. Noted changes in the epithelial alarmins concentration in the lung compartment during pirfenidone therapy may suggest its possible interaction with epithelial alarmins pathways in IPF. [ABSTRACT FROM AUTHOR]

This paper is a Part I of a literature review documentation describing the currently available and used techniques that are being explored by material scientists and researchers in the field of materials characterizations and testing for both thermal and environmental barrier coatings (TBCs and EBCs, respectively). This review contains relevant information regarding the most common coating applications and their impact on the durability and life of both the coatings and the substrate materials. It also includes a description of the methodologies of coating applications and their pros and cons. A discussion of the applicability, failure modes and modeling approaches that are presently available and utilized by active researchers in the field is also included. Part II will illustrate an in-depth assessment of various aspects of the available and developing life prediction models for both TBC and EBC and the influence of intrinsic and extrinsic factors on their thermal and mechanical stability. [ABSTRACT FROM AUTHOR]