Driven by the persisting poor understanding of the sluggish kinetics of the hydrogen evolution reaction (HER) on Pt in alkaline media, a direct correlation of the interfacial water structure and ...activity is still yet to be established. Herein, using Pt and Pt–Ni nanoparticles we first demonstrate a strong dependence of the proton donor structure on the HER activity and pH. The structure of the first layer changes from the proton acceptors to the donors with increasing pH. In the base, the reactivity of the interfacial water varied its structure, and the activation energies of water dissociation increased in the sequence: the dangling O−H bonds < the trihedrally coordinated water < the tetrahedrally coordinated water. Moreover, optimizing the adsorption of H and OH intermediates can re‐orientate the interfacial water molecules with their H atoms pointing towards the electrode surface, thereby enhancing the kinetics of HER. Our results clarified the dynamic role of the water structure at the electrode–electrolyte interface during HER and the design of highly efficient HER catalysts.
On nickel–platinum alloy nanoparticles under alkaline conditions, the reactivity of interfacial water varies with its structure and the order of water dissociation. The inclusion of nickel re‐orientates interfacial water molecules with their hydrogen atoms pointing towards the electrode surface, thereby enhancing the kinetics of the hydrogen evolution reaction (HER).
Metal‐containing nanoparticles (M‐NPs) in metal/nitrogen‐doped carbon (M‐N‐C) catalysts have been considered hostile to the acidic oxygen reduction reaction (ORR). The relation between M‐NPs and the ...active sites of metal coordinated with nitrogen (MNx) is hard to establish in acid medium owing to the poor stability of M‐NPs. Herein, we develop a strategy to successfully construct a new FeCo‐N‐C catalyst containing highly active M‐NPs and MN4 composite sites (M/FeCo‐SAs‐N‐C). Enhanced catalytic activity and stability of M/FeCo‐SAs‐N‐C is shown experimentally. Calculations reveal that there is a strong interaction between M‐NPs and FeN4 sites, which can favor ORR by activating the O−O bond, thus facilitating a direct 4 e− process. Those findings firstly shed light on the highly active M‐NPs and FeN4 composite sites for catalyzing acid oxygen reduction reaction, and the relevant reaction mechanism is suggested.
Highly active metal‐containing nanoparticles and FeN4 composite sites have been constructed. Experiment and calculation results reveal the enormous potential for activating the O−O bond and promoting the direct 4 e− dissociation pathway in the acidic oxygen reduction reaction (ORR), which could fundamentally improve ORR activity and inhibit the formation of reactive oxygen species.
To investigate the prevalence of congenital heart disease (CHD) in China based on a large prospective multicenter screening study.
A total of 122 765 consecutive infants born at 18 hospitals ...throughout China between August 1, 2011, and November 30, 2012, were included. Cases of CHD were identified by echocardiography, clinical assessment, and telephone follow-up.
The overall prevalence of CHD was 8.98 per 1000 live births (critical, 1.46; serious, 1.47; significant, 5.00; nonsignificant, 1.07), including 7.15 in male infants and 11.11 in female infants. The most common CHD was ventricular septal defect (3.3), followed by atrial septal defect (1.7), patent ductus arteriosus (0.78), pulmonary stenosis (0.73), tetralogy of Fallot (0.47), and transposition of the great arteries (0.35). Female predominance was observed for all CHD and mild CHD (significant and nonsignificant), and male predominance was observed for the critical CHDs. The proportion of preterm newborns was substantially higher among the major CHD cases (critical and serious) compared with normal newborns. There were appreciably more low birth weight infants among the critical CHD cases compared with normal newborns. Significantly higher rates of ventricular septal defect and atrioventricular septal defect were found in infants born to mothers aged ≥35 years. Extracardiac anomalies were found in 9.3% of CHD cases. The risk of CHD was increased by approximately 3-fold when a first-degree relative had CHD.
Our estimates are concordant with data from Western studies. This screening study may provide more accurate and complete information on the overall prevalence of CHD in China.
We previously found that human mesenchymal stem cells (MSC) or its conditioned medium restored lung protein permeability and reduced alveolar inflammation following Escherichia coli endotoxin-induced ...acute lung injury (ALI) in an ex vivo perfused human lung in part through the secretion of soluble factors such as keratinocyte growth factor (KGF). Recently, MSC were found to release microvesicles (MVs) that were biologically active because of the presence of mRNA or miRNA with reparative properties. MVs are circular fragments of membrane released from the endosomal compartment as exosomes or shed from the surface membranes. These studies were designed to determine if MVs released by human bone marrow derived MSCs would be effective in restoring lung protein permeability and reducing inflammation in E. coli endotoxin-induced ALI in C57BL/6 mice. The intratracheal instillation of MVs improved several indices of ALI at 48 hours. Compared to endotoxin-injured mice, MVs reduced extravascular lung water by 43% and reduced total protein levels in the bronchoalveolar lavage (BAL) fluid by 35%, demonstrating a reduction in pulmonary edema and lung protein permeability. MVs also reduced the influx of neutrophils and macrophage inflammatory protein-2 levels in the BAL fluid by 73% and 49%, respectively, demonstrating a reduction in inflammation. KGF siRNA-pretreatment of MSC partially eliminated the therapeutic effects of MVs released by MSCs, suggesting that KGF protein expression was important for the underlying mechanism. In summary, human MSC-derived MVs were therapeutically effective following E. coli endotoxin-induced ALI in mice in part through the expression of KGF mRNA in the injured alveolus.
Solid desiccant dehumidification is a promising alternative to vapor compression-based air-dehumidification to reduce energy consumption and improve air quality. Desiccant coated heat exchanger ...(DCHE), as one type of solid desiccant dehumidification system, can improve system performance and efficiency. The thermal performance and moisture removal capability of the DCHE greatly influence its dehumidification performance.
The present work aims to critically analyze the designs, materials, and manufacturing methods of heat exchangers used for solid desiccant coating and look into recent developments in regular heat exchangers, potentially deployed as a substrate for DCHE applications. A comprehensive literature review of publications regarding solid desiccant materials, heat exchangers, manufacturing and coating methods, binder materials, and the performance of heat exchangers has been developed. Alternative heat exchangers are described as better options than fin and tube heat exchangers that have been considered thus far for DCHE applications. Additionally, the heat exchanger's manufacturing process and materials over their thermal and mass exchange performance have been analyzed. Despite the widespread use of fin and tube heat exchangers for solid desiccant coating, recent developments in heat exchanger design, and related fields such as manufacturing methods and materials, open the possibilities for their application in solid desiccant dehumidification systems.
Finally, the authors provide their outlook on possible developments of DCHE technology, aiming to increase systems' energy and dehumidification performance.
•Alternative designs of desiccant coated heat exchanger might improve performance.•Novel designs of heat exchangers use materials like metal foam and wire structure.•Additive manufacturing allows to generate high surface area heat exchangers.•Heat transfer coefficient and surface area can improve dehumidification performance.
Microvesicles (MVs) derived from human mesenchymal stem cells (MSC MVs) were demonstrated to ameliorate inflammation in lungs. We have found their content of mRNA for keratinocyte growth factor was ...partly involved in their therapeutic effects. As MSC MVs also contained a substantial quantity of angiopoietin-1 (Ang-1) mRNA, which plays an essential role in vascular stabilization and resolving inflammation, we hypothesized that Ang-1 mRNA might similarly account for a part of their therapeutic effects. We downregulated Ang-1 mRNA expression in MVs, using a lentivirus vector carrying Ang-1 short hairpin RNA to transfect MSCs. A mouse model of lipopolysaccharide induced acute lung injury (ALI) was used in vivo. We also studied in vitro interactions between Ang-1 mRNA deficient MVs on macrophages and human lung microvascular endothelial cells. Compared with negative control, Ang-1 mRNA deficient MVs increased the influx of neutrophils and macrophage inflammatory protein-2 levels in bronchoalveolar lavage fluid by 136% and 105%, respectively, suggesting a deteriorative lung inflammation and a failure to restore pulmonary capillary permeability assessed by Evan's blue dye and bronchoalveolar lavage albumin level. In vitro, the addition of Ang-1 mRNA deficient MVs failed to maintain the integrity of endotoxin-stimulated microvascular endothelial cells and abrogated the decrease in tumor necrosis factor-α level and the increase in interleukin-10 level mediated by negative control in RAW 264.7 cells. In summary, the therapeutic effects of MVs in ALI, and their immunomodulatory properties on macrophages were partly mediated through their content of Ang-1 mRNA. Stem Cells 2017;35:1849-1859.
Isothermal membrane-based air dehumidification (IMAD), a recent emerged air dehumidification technology, separates the moisture from the humid air by using a selective membrane, through which only ...vapor molecules can transfer from the one side of the membrane at a high concentration to the other side at a low concentration. The IMAD process has superior performance potentially in energy and economic than other traditional dehumidification technologies. This paper comprehensively reviews the literature on IMAD including membrane characteristics, membrane configuration, membrane-related mass transport mechanism, and system design and operation, as well as the mass transfer modeling. State of the art in the IMAD is presented and finally the recommendations of future research are provided.
Since the outbreak of coronavirus disease 2019 (COVID-19), the National Health Commission of the People's Republic of China has issued a series of timely updated guidelines. 5–8 Type II alveolar ...epithelial cells show extensive hyperplasia, with some necrosis and desquamation. ...latest research has confirmed the postmortem persistence of 2019-nCoV in the lung tissue of the patients who experienced diffuse alveolar damage followed by rapidly evolving pulmonary fibrosis and respiratory failure. ...several complications, such as acute cardiac injury, acute kidney injury, abnormal coagulation function, shock, and even multi-organ dysfunction, tend to develop in critically ill patients. The previous clinical experience suggests that some patients with mild and moderate disease would inevitably evolve into critically ill states or may even die during hospitalization. ...the prognostic factors for patients at risk of developing more severe disease are of paramount importance in strengthening surveillance and enabling timely initiation of appropriate treatment.
This paper presents a multi-period active distribution network planning (ADNP) with distributed generation (DG). The objective of the proposed ADNP is to minimize the total planning cost, subject to ...both investment and operation constraints. The paper proposes a multi-stage stochastic optimization model to address DG uncertainties over several periods, in which the decisions are made sequentially by only using the present-stage information. A nested decomposition method is proposed which applies the stochastic dual dynamic integer programming (SDDIP) method to address computational intractabilities of the proposed ADNP approach. The presented numerical results and discussions on a 33-bus distribution system and a large-scale 906-bus system verify the effectiveness of the proposed ADNP method and its solution method.
Abstract
A dual‐network model (DNM) representing the topological characteristics of both the pore space and solid fraction of a packed bed was developed to study coupled incompressible water flow and ...heat transport from the pore‐scale to mesoscale (μm‐cm) with the consideration of temperature‐dependent fluid viscosity. The DNM was validated and used to study the temperature and velocity at the pore scale and their effects on fluid flow and heat transfer. Then the pore volume of the DNM was varied to illustrate the effect of bed porosity on transport processes, quantifying the trade‐off between flow conditions and heat transfer. This work demonstrates the ability of the DNM to simulate pore‐scale fluid flow and heat transfer simultaneously, which can then be averaged over the entire simulation domain to approximate meso/macroscopic parameters efficiently in relation to the pore geometry.
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