Combining pressure and electrochemistry to synthesize superhydrides.

Recently, superhydrides have been computationally identified and subsequently synthesized with a variety of metals at very high pressures. In this work, we evaluate the possibility of synthesizing superhydrides by uniquely combining electrochemistry and applied pressure. We perform computational searches using density functional theory and particle swarm optimization calculations over a broad range of pressures and electrode potentials. Using a thermodynamic analysis, we construct pressure-potential phase diagrams and provide an alternate synthesis concept, pressure-potential ([Formula: see text]), to access phases having high hydrogen content. Palladium-hydrogen is a widely studied material system with the highest hydride phase being Pd3H4 Most strikingly for this system, at potentials above hydrogen evolution and ∼ 300 MPa pressure, we find the possibility to make palladium superhydrides (e.g., PdH10). We predict the generalizability of this approach for La-H, Y-H, and Mg-H with 10- to 100-fold reduction in required pressure for stabilizing phases. In addition, the [Formula: see text] strategy allows stabilizing additional phases that cannot be done purely by either pressure or potential and is a general approach that is likely to work for synthesizing other hydrides at modest pressures.

Correlating the Role of Nanofillers with Active Layer Properties and Performance of Thin-Film Nanocomposite Membranes.

Thin-film nanocomposite (TFN) membranes are emerging water-purification membranes that could provide enhanced water permeance with similar solute removal over traditional thin-film composite (TFC) membranes. However, the effects of nanofiller incorporation on active layer physico-chemical properties have not been comprehensively studied. Accordingly, we aimed to understand the correlation between nanofillers, active layer physico-chemical properties, and membrane performance by investigating whether observed performance differences between TFN and control TFC membranes correlated with observed differences in physico-chemical properties. The effects of nanofiller loading, surface area, and size on membrane performance, along with active layer physico-chemical properties, were characterized in TFN membranes incorporated with Linde Type A (LTA) zeolite and zeolitic imidazole framework-8 (ZIF-8). Results show that nanofiller incorporation up to ~0.15 wt% resulted in higher water permeance and unchanged salt rejection, above which salt rejection decreased 0.9-25.6% and 26.1-48.3% for LTA-TFN and ZIF-8-TFN membranes, respectively. Observed changes in active layer physico-chemical properties were generally unsubstantial and did not explain observed changes in TFN membrane performance. Therefore, increased water permeance in TFN membranes could be due to preferential water transport through porous structures of nanofillers or along polymer-nanofiller interfaces. These findings offer new insights into the development of high-performance TFN membranes for water/ion separations.

Low-Pressure Electrochemical Synthesis of Complex High-Pressure Superconducting Superhydrides.

There is great current interest in multicomponent superhydrides due to their unique quantum properties under pressure. A remarkable example is the ternary superhydride Li_{2}MgH_{16} computationally identified to have an unprecedented high superconducting critical temperature T_{c} of ∼470 K at 250 GPa. However, the very high synthesis pressures required remains a significant hurdle for detailed study and potential applications. In this Letter, we evaluate the feasibility of synthesizing ternary Li-Mg superhydrides by the recently proposed pressure-potential (P^{2}) method that uniquely combines electrochemistry and applied pressure to control synthesis and stability. The results indicate that it is possible to synthesize Li-Mg superhydrides at modest pressures by applying suitable electrode potentials. Using pressure alone, no Li-Mg ternary hydrides are predicted to be thermodynamically stable, but in the presence of electrode potentials, both Li_{2}MgH_{16} and Li_{4}MgH_{24} can be stabilized at modest pressures. Three polymorphs are predicted as ground states of Li_{2}MgH_{16} below 300 GPa, with transitions at 33 and 160 GPa. The highest pressure phase is superconducting, while the two at lower pressures are not. Our findings point out the potentially important role of the P^{2} method in controlling phase stability of complex multicomponent superhydrides.

Hydrolytically Stable Ionic Fluorogels for High-Performance Remediation of Per- and Polyfluoroalkyl Substances (PFAS) from Natural Water.

PFAS are known bioaccumulative and persistent chemicals which pollute natural waters globally. There exists a lack of granular sorbents to efficiently remove both legacy and emerging PFAS at environmentally relevant concentrations. Herein, we report a class of polymer networks with a synergistic combination of ionic and fluorous components that serve as granular materials for the removal of anionic PFAS from water. A library of Ionic Fluorogels (IFs) with systematic variation in charge density and polymer network architecture was synthesized from hydrolytically stable fluorous building blocks. The IFs were demonstrated as effective sorbents for the removal of 21 legacy and emerging PFAS from a natural water and were regenerable over multiple cycles of reuse. Comparison of one IF to a commercial ion exchange resin in mini-rapid small-scale column tests demonstrated superior performance for the removal of short-chain PFAS from natural water under operationally relevant conditions.

Uncertainty quantification of DFT-predicted finite temperature thermodynamic properties within the Debye model.

Density functional theory (DFT) calculations are routinely used to screen for functional materials for a variety of applications. This screening is often carried out with a few descriptors, which use ground-state properties that typically ignore finite temperature effects. Finite-temperature effects can be included by calculating the vibration properties, and this can greatly improve the fidelity of computational screening. An important challenge for DFT-based screening is the sensitivity of the predictions to the choice of the exchange correlation function. In this work, we rigorously explore the sensitivity of finite temperature thermodynamic properties to the choice of the exchange correlation functional using the built-in error estimation capabilities within the Bayesian Error Estimation Functional-van der Waals (BEEF-vdW). The vibrational properties are estimated using the Debye model, and we quantify the uncertainty associated with finite-temperature properties for a diverse collection of materials. We find good agreement with experiment and small spread in predictions over different exchange correlation functionals for Mg, Al2O3, Al, Ca, and GaAs. In the case of Li, Li2O, and NiO, however, we find a large spread in predictions as well as disagreement between experiment and functionals due to complex bonding environments. While the energetics generated by the BEEF-vdW ensemble is typically normal, the complex mapping through the Debye model leads to the derived finite temperature properties having non-Gaussian behavior. We test a wide variety of probability distributions that best represent the finite temperature distribution and find that properties such as specific heat, Gibbs free energy, entropy, and thermal expansion coefficient are well described by normal or transformed normal distributions, while the prediction spread of volume at a given temperature does not appear to be drawn from a single distribution. Given the computational efficiency of the approach, we believe that uncertainty quantification should be routinely incorporated into finite-temperature predictions. In order to facilitate this, we have open-sourced the code base under the name dePye.

A hybrid functional study of native point defects in Cu2SnS3: implications for reducing carrier recombination.

The native point defects in the earth-abundant solar material Cu2SnS3 are studied using the hybrid functional. To generate more accurate formation energies of defects, the extended Freysoldt, Neugebauer, and Van de Walle (FNV) method is used for finite-size corrections in the charged supercell calculations. According to the calculated defect energetics, it is found that the usual experimental conditions can lead to abundant deep centers that deteriorate solar cell performance. To reduce the carrier recombination caused by the deep centers, Sn-rich and S-poor conditions should be attempted. The present calculations also give satisfactory explanations for a recent experimental work on the defect levels in Cu2SnS3.

THE RELATIONSHIP BETWEEN SERUM 25-HYDROXYVITAMIN D AND GLUCOSE HOMEOSTASIS IN OBESE CHILDREN AND ADOLESCENTS IN ZHEJIANG, CHINA.

OBJECTIVE: Evidence of the association between vitamin D, insulin resistance, and oral disposition index (oDI) in obese children and adolescents is limited. To fill this research gap, we measured serum 25-hydroxyvitamin D (25[OH]D) levels in obese children and analyzed the relationship between serum 25(OH)D levels and glucose homeostasis. METHODS: Altogether, 348 obese and 445 nonobese children and adolescents (age, 6 to 16 years) were enrolled in this study. Obese children were divided into 4 subgroups: normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and combined IFG and IGT (IFG+IGT) according to oral glucose tolerance test results. We measured serum 25(OH)D levels and calculated the homeostasis model assessment (HOMA) of insulin resistance (IR), the whole-body insulin sensitivity index (WBISI), and the disposition index. RESULTS: The levels of 25(OH)D in the obese group were significantly lower than in the nonobese group; serum 25(OH)D level in the NGT subgroup was higher than those of the other 3 subgroups, and it was significantly inversely correlated with logHOMA-IR (r = -0.090; P = .045) and positively correlated with logWBISI and logHOMA-oDI (r = 0.091, P = .049; and r = 0.108, P = .046, respectively). Obese patients with vitamin D deficiency thus have a significantly higher risk of disturbances in glucose metabolism. CONCLUSION: 25(OH)D deficiency or insufficiency is quite common in obese children and adolescents in Zhejiang, China. Obese patients with 25(OH)D deficiency (<30 nmol/L) are shown to be at higher risk for abnormal glucose metabolism.

Permanent neonatal diabetes mellitus in China.

BACKGROUND: Permanent neonatal diabetes mellitus (PNDM) is a rare disease, which is defined as the onset of diabetes before the age of 6 months with persistence through life. Infants with KCNJ11 or ABCC8 genetic mutations may respond to oral sulfonylurea therapy. Currently, there are limited studies about the genetic analysis and long-term follow-up of PNDM. CASE PRESENTATION: We report four cases of PNDM. None of the infants or their parents had INS, KCNJ11, or ABCC8 genetic mutations. One infant underwent continuous subcutaneous insulin infusion (CSII) and the other infants underwent multiple injections of insulin (MII). In these infants, PNDM persisted from 35 months to 60 months of follow-up. Three infants maintained fairly stable blood sugar levels, and one infant had poor sugar control. CONCLUSIONS: We suggest that all of the infants with PNDM should undergo genetic evaluation. For infants without KCNJ11 and ABCC8 genetic mutations, oral sulfonylurea should not be considered as treatment. CSII is a useful method for overcoming the difficulties of diabetes, and it may also improve the quality of life of both infants and their parents.

A Low Expression of NRF2 Enhances Oxidative Stress and Autophagy in Myofibroblasts, Promoting Progression of Chronic Obstructive Pulmonary Disease.

BACKGROUND: The inflammation phenotypes are often closely related to oxidative stress and autophagy pathway activation, which could be developed as a treatment target. AIMS: The aim of this study was to explore the underlying mechanism of inflammation in chronic obstructive pulmonary disease (COPD). METHODS: The lung tissue single-cell RNA-seq (scRNA-seq) dataset of GSE171541 was downloaded from the Gene Expression Omnibus (GEO) database. The marker genes were obtained from the CellMarker database. "Seurat" and "harmony" R packages were used for single-cell profiling analysis. Then, the "AUCell" R package was employed to calculate the reactive oxygen species (ROS) and autophagy pathway scores. Gene regulation network analysis was performed by applying the "SCENIC" package, followed by conducting correlation analysis with Spearman's rank correlation method. The cigarettes were used to develop a traumatic model in mice, and the expression of relevant genes was measured by qRT-PCR. RESULTS: The scRNA-seq analysis classified 12 cell subgroups in which the contractility of myofibroblasts was closely associated with the progression of COPD. Further analysis showed that ROS and autophagy pathways were significantly activated in myofibroblasts and that the nuclear factor erythroid 2-related factor 2 (NRF2) and its mediated oxidative stress pathway were inhibited in myofibroblasts. In addition, the downregulated NRF2 gene was negatively correlated with the expression of autophagy and ROS activation. In the traumatic mice model, NRF2 was downregulated in COPD mice but further elevated in the COPD+NRF2 mice group. Interestingly, the mRNA levels of Kelchlike ECH-associated protein 1 (Keap1), NADPH oxidase (NOX), and Cathepsin B (CTSB) were upregulated in COPD group in comparison to the control group but they were downregulated by NRF2. These results suggested that low-expressed NFR2 promoted autophagy and ROS pathway activation in myofibroblasts for COPD progression. CONCLUSION: We identified a cell myofibroblast cluster closely associated with COPD progression using the scRNA-seq analysis. The downregulated NFR2, as a key risk factor, mediated myofibroblast death by activating the oxidative stress and autophagy pathway for COPD progression.

Differentiable modeling and optimization of non-aqueous Li-based battery electrolyte solutions using geometric deep learning.

Electrolytes play a critical role in designing next-generation battery systems, by allowing efficient ion transfer, preventing charge transfer, and stabilizing electrode-electrolyte interfaces. In this work, we develop a differentiable geometric deep learning (GDL) model for chemical mixtures, DiffMix, which is applied in guiding robotic experimentation and optimization towards fast-charging battery electrolytes. In particular, we extend mixture thermodynamic and transport laws by creating GDL-learnable physical coefficients. We evaluate our model with mixture thermodynamics and ion transport properties, where we show improved prediction accuracy and model robustness of DiffMix than its purely data-driven variants. Furthermore, with a robotic experimentation setup, Clio, we improve ionic conductivity of electrolytes by over 18.8% within 10 experimental steps, via differentiable optimization built on DiffMix gradients. By combining GDL, mixture physics laws, and robotic experimentation, DiffMix expands the predictive modeling methods for chemical mixtures and enables efficient optimization in large chemical spaces.

Phase Diagrams of Alloys and Their Hydrides via On-Lattice Graph Neural Networks and Limited Training Data.

Efficient prediction of sampling-intensive thermodynamic properties is needed to evaluate material performance and permit high-throughput materials modeling for a diverse array of technology applications. To alleviate the prohibitive computational expense of high-throughput configurational sampling with density functional theory (DFT), surrogate modeling strategies like cluster expansion are many orders of magnitude more efficient but can be difficult to construct in systems with high compositional complexity. We therefore employ minimal-complexity graph neural network models that accurately predict and can even extrapolate to out-of-train distribution formation energies of DFT-relaxed structures from an ideal (unrelaxed) crystallographic representation. This enables the large-scale sampling necessary for various thermodynamic property predictions that may otherwise be intractable and can be achieved with small training data sets. Two exemplars, optimizing the thermodynamic stability of low-density high-entropy alloys and modulating the plateau pressure of hydrogen in metal alloys, demonstrate the power of this approach, which can be extended to a variety of materials discovery and modeling problems.

Facile Synthesis of Electrically Conductive Membranes.

A facile and effective strategy that can be used to fabricate electrically conductive membranes (ECMs) of diverse filtration performance (i.e., water productivity and solute rejection) is not available yet. Herein, we report a facile method that enables the fabrication of ECMs of a broad performance range. The method is based on the use of polyethylenimine (PEI), glutaraldehyde, and any of a diverse set of conductive materials to cast an electrically conductive layer atop any of a diverse set of substrates (i.e., from microfiltration to reverse osmosis membranes). We developed the reported ECM fabrication method using graphite as the conductive material and PVDF membranes as substrates. We demonstrate that graphite-PVDF ECMs were stable and electrically conductive and could be successfully used for solute filtration and electrochemical degradation. We also confirmed that the PEI/glutaraldehyde-based ECM fabrication method is suitable for conductive materials other than graphite, including carbon nanotubes, reduced graphene oxide, activated charcoal, and silver nanoparticles. Compared with the substrates used for their fabrication, ECMs showed low electrical sheet resistances that varied with conductive material, increased solute rejection, and reduced water permeance. Taken together, this work presents a promising general strategy for the fabrication of ECMs for environmental applications from diverse substrates and conductive materials.

Intercellular Communication-Related Molecular Subtypes and a Gene Signature Identified by the Single-Cell RNA Sequencing Combined with a Transcriptomic Analysis.

Background: The tumor microenvironment (TME) of lung adenocarcinoma (LUAD) comprise various cell types that communicate with each other through ligand-receptor interactions. This study focused on the identification of cell types in LUAD by single-cell RNA sequencing (scRNA-seq) data and screening of intercellular communication-related genes. Methods: The Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo) provided the RNA-seq data of LUAD patients in the GSE149655, GSE31210, and GSE72094 datasets. Quality control of the scRNA-seq data in GSE149655 was performed by the Seurat package (http://seurat.r-forge.r-project.org) for identifying highly variable genes for principal component analysis (PCA) and cell clustering. The CellPhoneDB (http://www.cellphonedb.org) was used for filtering intercellular communication-related ligand-receptor pairs. According to ligand and receptor expressions, LUAD samples were clustered using ConsensusClusterPlus (https://www.bioconductor.org/packages/release/bioc/html/ConsensusClusterPlus). Additionally, the identification of prognosis-related ligand and receptor genes was conducted along with the development of a risk prediction model by the least absolute shrinkage and selection operator (LASSO) Cox regression analysis. Results: This study identified twelve cell types in 8170 cells of LUAD tissues along with 219 ligand and receptor genes. LUAD was classified into three different molecular subtypes, among which cluster 3 (C3) had the longest overall survival (OS) time and cluster (C1) had the shortest OS time. In comparison with the other two molecular subtypes, it was observed that C1 had a higher rate of somatic mutations and lower levels of infiltrating immune cells and immune scores. Ten genes were screened from the total ligand and receptor genes to construct a risk model, which showed a strong prediction power in the prognosis of patients with LUAD. Conclusion: The results of this study revealed cell types specific to LUAD, which were classified into different molecular subtypes according to intercellular communication-related genes. A novel prognostic risk model was developed in this study, providing new insights into prognostic assessment models for LUAD.

Linear versus Nonlinear Aromatic Polyamides: The Role of Backbone Geometry in Thin Film Salt Exclusion Membranes.

Two aromatic polyamides─poly(3,3'-dihydroxybenzidine terephthalamide) (DHTA) and poly(3,3'-dihydroxybenzidine isophthalamide) (DHIA)─are compared for their ability to remove salts from water. DHTA is linear and rigid whereas DHIA is nonlinear and semirigid. DHTA and DHIA were selected as they allow us to investigate the effect of polymer backbone geometry on salt exclusion in a non-crosslinked thin film membrane, independently of the backbone chemistry. Because of their differences in solution viscosity, spin coating parameters for DHTA and DHIA solutions were optimized separately to produce thin film composites (TFCs) with reproducible membrane properties. The resulting DHTA TFCs displayed salt rejections of 87.8% (NaCl), 97.0% (MgSO4), and 80.3% (CaCl2). In comparison, DHIA TFCs demonstrated poor salt rejections of 21.0% (NaCl), 29.3% (MgSO4), and 15.4% (CaCl2). Cross-sectional SEM images of DHTA and DHIA films reveal that DHTA has a stratified (layered) morphology whereas DHIA exhibits a dense, featureless morphology. Both DHTA and DHIA TFCs exhibit similar surface morphology, contact angle, surface charge, and water uptake. PEG rejection experiments indicate that the average pore size of DHTA TFCs is ∼2 nm while DHIA TFCs have an average pore size of ∼3 nm. Our findings illustrate that using a rigid, linear aromatic polyamide gives an active layer with a stratified morphology, uniplanar orientation, smaller pores, and higher salt rejection, whereas the nonlinear aromatic polyamide analogue results in an isotropic active layer with larger pores and lower salt rejection.

[Rosuvastatin attenuates vascular endothelial adhesiveness in apolipoprotein E-deficient mice].

OBJECTIVE: To investigate the anti-inflammatory effects on the vessel wall of rosuvastatin in apolipoprotein E-deficient mice. METHODS: Eight-week-old apolipoprotein E-deficient mice fed a normal chow diet were treated with vehicle or various doses of rosuvastatin (1, 5, or 20 mg/kg) by subcutaneous injection for 2 or 6 weeks prior to sacrifice. Endothelial adhesiveness for monocytes was determined by functional binding assay. The expressions of vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 in the vessel wall were detected by quantitative real-time polymerase chain reaction. RESULTS: Endothelial adhesiveness for monocytes was significantly attenuated after 2 or 6 weeks treatments with 5 or 20 mg/kg rosuvastatin. Rosuvastatin also significantly reduced the expressions of vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 in the vessel wall. CONCLUSION: The anti-inflammatory effects of suvastatin might be responsible for attenuating the pathogenesis of atherogenesis in apolipoprotein E-deficient mice.

Recent advances in membrane development for treating surfactant- and oil-containing feed streams via membrane distillation.

Membrane distillation (MD) has been touted as a promising technology for niche applications such as desalination of surfactant- and oil-containing feed streams. Hitherto, the deployment of conventional hydrophobic MD membranes for such applications is limited and unsatisfactory. This is because the presence of surfactants and oils in aqueous feed streams reduces the surface-tension of these media significantly and the attachment of these contaminants onto hydrophobic membrane surfaces often leads to membrane fouling and pore wetting, which compromises on the quantity and quality of water recovered. Endowing MD membranes with surfaces of special wettabilities has been proposed as a strategy to combat membrane fouling and pore wetting. This involves the design of local kinetic energy barriers such as multilevel re-entrant surface structures, surfaces with ultralow surface-energies, and interfacial hydration layers to impede transition to the fully-wetted Wenzel state. This review critiques the state-of-the-art fabrication and surface-modification methods as well as practices used in the development of omniphobic and Janus MD membranes with specific emphasis on the advances, challenges, and future improvements for application in challenging surfactant- and oil-containing feed streams.

Hierarchically Structured Janus Membrane Surfaces for Enhanced Membrane Distillation Performance.

Commercial hydrophobic poly(vinylidene fluoride) (PVDF) membranes are vulnerable to membrane fouling and pore wetting, hampering the use of membrane distillation (MD) for the treatment of surfactant- and oil-containing feed streams. To address these challenges, we designed novel Janus membranes with multilevel roughness to mitigate foulant adhesion and prevent pore wetting. Specifically, fouling- and wetting-resistant Janus MD membranes with hierarchically structured surfaces were tailored via a facile technique that involved oxidant-induced dopamine polymerization followed by in situ immobilization of silver nanoparticles (AgNPs) on commercial PVDF hollow fiber substrates. These membranes demonstrated outstanding antifouling properties and salt rejection performances in comparison to membranes with single-level structures. We ascribed the membranes' excellent performances to the coupled effects of improved surface hydrophilicity and self-healing mechanism brought about by AgNPs. Furthermore, the newly engineered membranes exhibited antibacterial properties in Bacillus acidicola solutions as evidenced by clear inhibition zones observed on a confocal laser scanning microscope. The development of hierarchically structured Janus MD membranes with multilevel roughness paves a way to mitigate membrane fouling and pore wetting caused by low-surface-tension feed streams in the MD process.

Microsatellite DNA variation of the gametophyte clones isolated from introduced Laminaria japonica (Phaeophyta) and L. longissima of China and varieties derived from them.

The variation of 90 Laminaria gametophyte clones representing the introduced Laminaria japonica (Group 1) and Laminaria longissima (Group 2), the varieties of L. japonica (Group 3) and the varieties derived from interspecific hybrids (Group 4) was determined with 18 microsatellite markers. The allelic diversity and Nei's gene diversity of Group 1 were significantly higher than those of Group 2 (2.9 vs. 1.8 and 0.414 vs. 0.161, respectively), demonstrating that the variation of the introduced L. japonica is richer than that of L. longissima. Both allelic diversity and Nei's gene diversity of Group 3 were lower than those of Group 1, indicating that only a portion of variation of L. japonica was incorporated into the varieties of L. japonica. Significant genetic differentiation was detected between four groups and between female (Population 1) and male (Population 2) gametophyte clones in each group. The variation among groups accounted for 39.95%, while that among populations accounted for 21.65% of the total. The genetic distance between Group 1 and Group 4 was obviously longer than that between Group 2 and Group 4 (0.686 vs. 0.291), indicating that maternal gametophyte clone contributed more variation to the hybrids than the paternal gametophyte clone did.

The Role of Malic Enzyme on Promoting Total Lipid and Fatty Acid Production in Phaeodactylum tricornutum.

To verify the function of malic enzyme (ME1), the ME1 gene was endogenously overexpressed in Phaeodactylum tricornutum. Overexpression of ME1 increased neutral and total lipid content and significantly increased saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) in transformants, which varied between 23.19 and 25.32% in SFAs and between 49.02 and 54.04% in PUFAs, respectively. Additionally, increased ME1 activity was accompanied by elevated NADPH content in all three transformants, indicating that increased ME1 activity produced additional NADPH comparing with that of WT. These results indicated that ME1 activity is NADP-dependent and plays an important role in the NADPH levels required for lipid synthesis and fatty acid desaturation in P. tricornutum. Furthermore, our findings suggested that overexpression of endogenous ME1 represents a valid method for boosting neutral-lipid yield in diatom.

Cigarette smoke extract promotes proliferation of airway smooth muscle cells through suppressing C/EBP-α expression.

Cigarette smoke has been considered a major contributor to the pathogenesis of chronic obstructive pulmonary disease (COPD). In COPD patients, the airway smooth muscle layer has been observed to be markedly thickened and the proliferation of airway smooth muscle cells (ASMCs) was therefore used by the present study as a model to assess the impact of cigarette smoke extract (CSE). ASMCs were exposed to various concentrations of CSE and the proliferation of the cells was analyzed by an MTT assay. Furthermore, the expression levels of calreticulin and CCAAT/enhancer-binding protein alpha (C/EBP-α) in CSE-stimulated ASMCs were determined by polymerase chain reaction and western blot analyses. In addition, the effects of RNA interference (RNAi) to knockdown calreticulin and/or C/EBP-α on ASMC proliferation were studied. CSE was found to promote the proliferation of ASMCs, which was associated with increased expression of calreticulin and decreased expression of C/EBP-α. Knockdown of calreticulin resulted in the upregulation of C/EBP-α and inhibition of cell proliferation, while simultaneous knockdown of C/EBP-α promoted cell proliferation. The present study revealed that CSE promoted the proliferation of ASMCs, which was mediated by inhibition of C/EBP-α. These findings shed new light on airway remodeling in COPD and may provide novel approaches for therapies.