Background
While the clinical characteristics and outcomes of asthma‐chronic obstructive pulmonary disease (COPD) overlap (ACO) have been frequently compared with those of COPD or asthma, the ...prevalence and features of ACO in patients with severe asthma are unclear.
Objectives
Evaluation of the prevalence and clinical features of ACO using the Korean severe asthma registry.
Methods
At the time of registration, ACO was determined in patients with severe asthma by attending specialists. Patients were classified into ACO and non‐ACO groups, and the demographic and clinical characteristics of these two groups were compared.
Results
Of 482 patients with severe asthma, 23.7% had ACO. Patients in the ACO group were more likely to be male (P < .001), older (P < .001), and ex‐ or current smokers (P < .001) compared with those in the non‐ACO group. Patients in the ACO group had lower mean forced expiratory volume in 1 second (P < .001) and blood eosinophil percentage (P = .006), but higher blood neutrophil percentage (P = .027) than those in the non‐ACO group. The ACO group used more inhaled long‐acting muscarinic antagonist (P < .001), methylxanthine (P = .001), or sustained systemic corticosteroid (P = .002). In addition, unscheduled emergency department visits due to exacerbation were more frequent in the ACO group (P = .006).
Conclusion
Among patients with severe asthma, those with ACO were older, predominantly male, and were more likely to have a smoking history than those with asthma only. Patients with ACO used more systemic corticosteroid and had more frequent exacerbations related to emergency department visits than those with severe asthma only.
We found that about one‐fourth of patients with severe asthma was diagnosed with ACO by specialists. The most common reason for ACO diagnosis was smoking history. ACO patients were predominantly male, older, and had more smoking history compared with non‐ACO patients. ACO patients had higher blood neutrophil count, but lower lung function. ACO patients used more LAMA, methylxanthine, and systemic corticosteroid and had more frequent exacerbations related to ER visits compared with those with severe asthma only. Abbreviations: ACO, asthma‐COPD overlap; ER, emergency room; FEV1, forced expiratory volume in one second.
The endoplasmic reticulum (ER) is an important intracellular compartment in eukaryotic cells and has diverse functions, including protein synthesis, protein folding, lipid metabolism and calcium ...homeostasis. ER functions are disrupted by various intracellular and extracellular stimuli that cause ER stress, including the inhibition of glycosylation, disulphide bond reduction, ER calcium store depletion, impaired protein transport to the Golgi, excessive ER protein synthesis, impairment of ER‐associated protein degradation and mutated ER protein expression. Distinct ER stress signalling pathways, which are known as the unfolded protein response, are deployed to maintain ER homeostasis, and a failure to reverse ER stress triggers cell death. Sphingolipids are lipids that are structurally characterized by long‐chain bases, including sphingosine or dihydrosphingosine (also known as sphinganine). Sphingolipids are bioactive molecules long known to regulate various cellular processes, including cell proliferation, migration, apoptosis and cell–cell interaction. Recent studies have uncovered that specific sphingolipids are involved in ER stress. This review summarizes the roles of sphingolipids in ER stress and human diseases in the context of pathogenic events.
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•Novel rGO/ZrO2/Ag3PO4 composite was synthesized via a green hydrothermal approach.•Contaminant degradation by adsorption–photocatalysis synergy was confirmed.•Optimal band-edge ...alignment of ZrO2/Ag3PO4 provided high photocatalytic performance.•Structural stability and reusability of the composite favor practical applications.•The quantum yield of this system exceeds previously reported values.
Synergy between surface adsorption and photocatalysis is key for effective contaminant degradation in the liquid phase. Herein, we report a heterojunction photocatalyst of reduced graphene oxide (rGO)/zirconium dioxide (ZrO2)/silver phosphate (Ag3PO4) that incorporates this synergy for 4-nitrophenol (PNP) removal. Compared with other photocatalyst combinations, ZrO2 and Ag3PO4 coupling generates reactive species with greater degradation potential. ZrO2 and rGO were synthesized by a green approach using a one-step hydrothermal reaction in ethanol–water. The growth of rGO/ZrO2 and Ag3PO4 were accomplished and the functions of each part were well developed together. The rGO/ZrO2/Ag3PO4 composite exhibited enhanced light absorption and a low band gap energy (2.3 eV) owing to rGO and Ag3PO4 integration. The composite’s photocatalytic activity was much higher than that of ZrO2, Ag3PO4, or ZrO2/Ag3PO4. The maximal adsorption of PNP was 26.88 mg/g, and a pseudo-first-order model described the PNP degradation kinetics (k = 0.034 min−1). Synergy between the three components resulted in 97% PNP removal in 90 min, and even after five cycles, 94% PNP removal was obtained. The quantum yield of the system (7.31 × 10−5 molecules/photon) was compared with those in previous reports to assess the photocatalytic performance and energy requirements.
Acute respiratory distress syndrome is a major cause of respiratory failure in critically ill patients. Despite extensive research into its pathophysiology, mortality remains high. No effective ...pharmacotherapy exists. Based largely on numerous preclinical animal studies, administration of mesenchymal stem or stromal cell (MSC) as a therapeutic for acute lung injury (ALI) holds great promise, and Phase I and II clinical trials are currently under way internationally. However, concern for the use of stem cells, specifically the risk of iatrogenic tumor formation, as well as the prohibitive cost of production, storage, and distribution of cells in bone marrow transplant facilities, may limit access to this lifesaving therapy. Accumulating evidence now suggest that novel stem cell–derived therapies, including MSC‐conditioned medium and extracellular vesicles (EVs) released from MSCs, might constitute compelling alternatives. The current review summarizes the preclinical studies testing MSC EVs as treatment for ALI and other inflammatory lung diseases. While certain logistic obstacles limit the clinical applications of MSC‐conditioned medium such as the volume required for treatment and lack of standardization of what constitutes the components of conditioned medium, the therapeutic application of MSC EVs remains promising, primarily due to ability of EVs to maintain the functional phenotype of the parent cell. However, utilization of MSC EVs will require large‐scale production and standardization concerning identification, characterization, and quantification.
The probability of nonradiative transitions in photochemical dynamics is determined by the derivative couplings, the couplings between different electronic states through the nuclear degrees of ...freedom. Efficient and accurate evaluation of the derivative couplings is, therefore, of central importance to realize reliable computer simulations of photochemical reactions. In this work, the derivative couplings for multistate multireference second-order perturbation theory (MS-CASPT2) and its “extended” variant (XMS-CASPT2) are studied, in which we present an algorithm for their analytical evaluation. The computational costs for evaluating the derivative couplings are essentially the same as those for calculating the nuclear energy gradients. The geometries and energies calculated with XMS-CASPT2 for small molecules at minimum energy conical intersections (MECIs) are in good agreement with those computed by multireference configuration interaction. As numerical examples, MECIs are optimized using XMS-CASPT2 for stilbene and a green fluorescent protein model chromophore (the 4-para-hydroxybenzylidene-1,2-dimethyl-imidazolin-5-one anion).
Biodegradable polymers are seen as a potential solution to the environmental problems generated by plastic waste. In particular, the renewable aliphatic polyesters of poly(hydroxyacid)-type ...homopolymers and copolymers consisting of polylactic acid (PLA), poly(glycolic acid) (PGA), and poly(e-caprolactone) (PCL) constitute the most promising bioresorbable materials for applications in biomedical and consumer applications. Among those polymers, PLA has attracted particular attention as a substitute for conventional petroleum-based plastics. PLA is synthesized by the fermentation of renewable agricultural sources, including corn, cellulose, and other polysaccharides. Although some of its characteristics are disadvantageous (e.g., poor melt properties, mechanical brittleness, low heat resistance, and slow crystallization), there exist potential routes to resolve these shortcomings. These include copolymerization, blending, plasticization modification, or the addition of reinforcing phases (e.g., chitosan (Cs), cellulose, and starch). In this review, we discuss the degradation mechanisms of PLA and its modified form in the environment, current issues that hinder the achievement of good Cs/PLA combination, and ways to overcome some of these problems. Furthermore, our discussion is extended to cover the subjects of hydrolytic degradation and weathering effects with different Cs/PLA blends.
It is essential and important to determine the adsorption mechanism as well as removal efficiency when using an adsorption technique to remove toxic heavy metals from wastewater. In this research, ...the removal efficiency and mechanism of chromium removal by a silica-based nanoparticle were investigated. A PEI-silica nanoparticle was synthesized by a one-pot technique and exhibited uniformly well-dispersed PEI polymers in silica particles. The adsorption capacity of chromium ions was determined by a batch adsorption test, with the PEI-silica nanoparticle having a value of 183.7 mg/g and monolayer sorption. Adsorption of chromium ions was affected by the solution pH and altered the nanoparticle surface chemically. First principles calculations of the adsorption energies for the relevant adsorption configurations and XPS peaks of Cr and N showed that Cr(VI), HCrO
is reduced to two species, Cr(III), CrOH
and Cr
, by an amine group and that Cr(III) and Cr(VI) ions are adsorbed on different functional groups, oxidized N and NH
.
Nanobubble and ultrasonic cavitation were applied to support and prolong oxidation reactions of ozonation. Nanobubbles increased ozone dissolution by a factor of 16 due to low buoyancy, high surface ...area, and stability in water. Hydroxyl radicals generated by ultrasonic cavitation produced hydrogen peroxide rather than recombining due to additional oxygen atoms supplied by the nanobubbles. The generated hydrogen peroxide formed hydroperoxyl ions that reacted with ozone to generate hydroxyl radicals. The process achieved improvements in both the loss of emitted ozone and radical recombination. Rhodamine B decomposition was used to gauge the effectiveness of the process, with the highest rhodamine B decomposition evident at a high initial pH and power and a frequency of 132 kHz as revealed in ultrasonic experiments. The process achieved more than 99% of the rhodamine B decomposition in 20 min under the most efficient conditions. The generation of hydrogen peroxide exhibited tendencies similar to those of rhodamine B decomposition, supporting the proposed mechanism. An ozonation process combined with nanobubble and ultrasonic cavitation can therefore sustain oxidizing power using continuous dissolution by nanobubbles and successive radical generation caused by hydrogen peroxide generated by cavitation.
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•Nanobubbles reduced ozone release into the atmosphere.•Ultrasonic cavitation broke the nanobubbles and increased the gas transfer.•Ultrasonic cavitation promoted ozone consumption through hydrogen peroxide production.•Nanobubbles increase the production of hydrogen peroxide by supplying oxygen.
An analytical gradient theory for single-state N-electron valence state perturbation theory (NEVPT2), using both strongly contracted (SC) and partially contracted (PC) internal contraction schemes, ...is developed. We demonstrate the utility of the developed algorithm in the optimization of the single-state molecular geometry of acrolein, benzyne, benzene, the retinal chromophore PSB3, the GFP chromophore pHBI, and porphine, with the cc-pVTZ basis sets. The SC-NEVPT2 analytical gradients exhibit numerical instability due to the lack of invariance with respect to the rotations among the inactive orbitals. On the other hand, PC-NEVPT2 gives molecular geometries comparable to the second-order complete active space perturbation theory in any tested cases. We discuss possible future developments that will make the NEVPT2 gradient algorithm a powerful tool for optimizing molecular geometries and conducting molecular dynamics simulations of correlated systems.
Our previous study demonstrated that mesenchymal stem cell (MSC) microvesicles (MV) reduced lung inflammation, protein permeability, and pulmonary edema in endotoxin‐induced acute lung injury in ...mice. However, the underlying mechanisms for restoring lung protein permeability were not fully understood. In this current study, we hypothesized that MSC MV would restore protein permeability across injured human lung microvascular endothelial cells (HLMVEC) in part through the transfer of angiopoietin‐1 (Ang1) mRNA to the injured endothelium. A transwell coculture system was used to study the effect of MSC MV on protein permeability across HLMVECs injured by cytomix, a mixture of IL‐1β, TNF‐α, and IFN‐γ (50 ng/ml). Our result showed that cytomix significantly increased permeability to FITC‐dextran (70 kDa) across HLMVECs over 24 hours. Administration of MSC MVs restored this permeability in a dose dependent manner, which was associated with an increase in Ang1 mRNA and protein secretion in the injured endothelium. This beneficial effect was diminished when MSC MV was pretreated with an anti‐CD44 antibody, suggesting that internalization of MV into the HLMVEC was required for the therapeutic effect. Fluorescent microscopy showed that MSC MV largely prevented the reorganization of cytoskeleton protein F‐actin into “actin stress fiber” and restored the location of the tight junction protein ZO‐1 and adherens junction protein VE‐cadherin in injured HLMVECs. Ang1 siRNA pretreatment of MSC MV prior to administration to injured HLMVECs eliminated the therapeutic effect of MV. In summary, MSC MVs restored protein permeability across HLMVEC in part by increasing Ang1 secretion by injured HLMVEC. Stem Cells Translational Medicine 2018;7:615–624
Mesenchymal stem cell microvesicles restored protein permeability across injured human lung microvascular endothelial cells in part by transferring mRNA for angiopoietin‐1 from the microvesicles to the injured endothelium, preventing actin stress fiber formation. Data are presented as mean ± SD, N = 9, *, p is significant vs. control using ANOVA with post hoc Tukey HSD test.
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