A fundamental understanding of polymer microstructure is important in order to design novel polymer electrolyte membranes (PEMs) with excellent electrochemical performance and stabilities. ...Hydrocarbon-based polymers have distinct microstructure according to their chemical structure. The ionic clusters and/or channels play a critical role in PEMs, affecting ion conductivity and water transport, especially at medium temperature and low relative humidity (RH). In addition, physical properties such as water uptake and dimensional swelling behavior depend strongly on polymer morphology. Over the past few decades, much research has focused on the synthetic development and microstructural characterization of hydrocarbon-based PEM materials. Furthermore, blends, composites, pressing, shear field, electrical field, surface modification, and cross-linking have also been shown to be effective approaches to obtain/maintain well-defined PEM microstructure. This review summarizes recent work on developments in advanced PEMs with various chemical structures and architecture and the resulting polymer microstructures and morphologies that arise for potential application in fuel cell, lithium ion battery, redox flow battery, actuators, and electrodialysis.
The enhanced stability of lithium metal is vital to the development of high energy density lithium batteries due to its higher specific capacity and low redox potential. Herein, we demonstrate that ...nitrogen and sulfur codoped graphene (NSG) nanosheets coated on a polyethylene separator stabilized the lithium electrode in lithium metal batteries by effectively suppressing dendrite growth and maintaining a uniform ionic flux on the metal surface. The ultrathin layer of NSG nanosheets also improved the dimensional stability of the polymer separator at elevated temperatures. In addition, the enhanced interfacial interaction between the NSG-coated separator and lithium metal via electrostatic attraction released the surface tension of lithium metal and suppressed the initiation of dendrite growth on lithium metal. As a result, the electrochemical performance of a lithium metal cell composed of a LiNi0.8Co0.15Al0.05O2 positive electrode with an NSG-coated separator was remarkably improved as compared to the cell with an uncoated polyethylene separator.
Methicillin-resistant Staphylococcus aureus (MRSA) are spread among infected patients, with infection rates increasing at an alarming rate. Furthermore, increased resistance to antibiotics has ...resulted in serious challenges in the treatment of infectious diseases worldwide. Under the selection pressure of exposure to antibiotics, microorganisms evolve to survive against the new conditions imposed by therapy. Therefore, there exists a need to develop alternative natural or combination drug therapies. Curcumin (CCM), a natural polyphenolic flavonoid isolated from the rhizome of a plant, Curcuma longa Linné., has been found to possess many beneficial biological activities. The aim of this study was to investigate the synergistic effect of curcumin and antibiotics as well as to determine the antibacterial activity of CCM against specific MRSA strains. The antibacterial activity of CCM was assessed by the broth microdilution method (by calculating the minimal inhibitory concentration MIC), checkerboard dilution test, and time-kill assay. Antimicrobial activity of CCM was observed against all tested strains. The MICs of CCM against 10 strains of S. aureus ranged from 125 to 250μg/ml. In the checkerboard test, CCM markedly reduced the MICs of the antibiotics oxacillin (OXI), ampicillin (AMP), ciprofloxacin (CIP), and norfloxacin (NOR) used against MRSA. The time-kill curves showed that a combined CCM and OXI treatment reduced the bacterial counts below the lowest detectable limit after 24h. This study suggested that CCM reduced the MICs of several antibiotics tested, notably of OXI, AMP, CIP, and NOR, and that CCM in combination with antibiotics could lead to the development of new combination of antibiotics against MRSA infection.
Long-term exposure to particulate matter (PM) with aerodynamic
diameters < 10 (PM10) and 2.5 µm (PM2.5) has
negative effects on human health. Although station-based PM monitoring has
been conducted ...around the world, it is still challenging to provide spatially
continuous PM information for vast areas at high spatial resolution.
Satellite-derived aerosol information such as aerosol optical depth (AOD) has
been frequently used to investigate ground-level PM concentrations. In this
study, we combined multiple satellite-derived products including AOD with
model-based meteorological parameters (i.e., dew-point temperature, wind
speed, surface pressure, planetary boundary layer height, and relative
humidity) and emission parameters (i.e., NO, NH3, SO2,
primary organic aerosol (POA), and HCHO) to estimate surface PM concentrations over South Korea. Random
forest (RF) machine learning was used to estimate both PM10 and
PM2.5 concentrations with a total of 32 parameters for 2015–2016. The
results show that the RF-based models produced good performance resulting in
R2 values of 0.78 and 0.73 and root mean square errors (RMSEs) of 17.08 and
8.25 µg m−3 for PM10 and
PM2.5, respectively. In particular, the proposed models successfully
estimated high PM concentrations. AOD was identified as the most significant
for estimating ground-level PM concentrations, followed by wind speed, solar
radiation, and dew-point temperature. The use of aerosol information derived
from a geostationary satellite sensor (i.e., Geostationary Ocean Color Imager, GOCI) resulted in slightly
higher accuracy for estimating PM concentrations than that from a
polar-orbiting sensor system (i.e., the Moderate Resolution
Imaging Spectroradiometer, MODIS). The proposed RF models yielded
better performance than the process-based approaches, particularly in
improving on the underestimation of the process-based models (i.e., GEOS-Chem
and the Community Multiscale Air Quality Modeling System, CMAQ).
This new approach for adsorption and elimination of toxic substances entering the lung represents an alternative defense mechanism against exposure to nitrates from particulate matter.
Display ...omitted
Airborne particulate matter has been designated as a class 1 carcinogen by the World Health Organization. Nitrate is a toxic substance that accounts for a large proportion of particulate matter, and nitrate toxicity has long been reported.
In this study, we aimed to optimize the adsorption and removal of particulate matter containing nitrate for effective elimination by the lungs. To this end, particles were designed to optimize the inhalation and removal efficiencies. These particles were prepared as chitosan-based particles containing N-acetylcysteine by using emulsion diffusion methods. Chitosan adsorbs nitrate, while N-acetylcysteine dissolves mucus. This removal mechanism has been found to occur in various in vitro models that mimic respiratory environments and in vivo models.
In particular, the removal of exogenous substances, such as particulate matter, by the motility of respiratory cilia through mucolytic effect was investigated. This new approach for the adsorption and elimination of toxic substances entering the lungs represents an alternative defense mechanism against exposure to nitrates from air pollution.
Sulfonated SiO2 particles containing poly(lithium 4-styrenesulfonte) in their shell are synthesized and used as coating materials for the preparation of ceramic-coated separators for lithium-ion ...cells. The ceramic-coated separators exhibit good thermal stability and wettability for liquid electrolyte due to the presence of a heat-resistant silica with hydrophilic poly(lithium 4-styrenesulfonte). By using these ceramic-coated separators, lithium-ion cells composed of a carbon negative electrode and a LiNi1/3Co1/3Mn1/3O2 positive electrode are assembled and their cycling performances are evaluated. The cells assembled with the ceramic-coated separators demonstrate superior cycling performance compared to cell prepared with a polyethylene separator.
► Core–shell SiO2 particles are used as coating materials for ceramic-coated separators. ► The ceramic-coated separators exhibit good thermals stability and wettability. ► The cells assembled with ceramic-coated separators exhibit good cycling performance.
Endoscopic transsphenoidal surgery (ETSS) is emerging as an effective, minimally invasive surgery technique for brain tumors of the pituitary fossa. Using a surgical endoscope, surgeons can obtain a ...broader, nearer, and more apparent visual field with minimal keyhole entrance. However, ETSS may require a steep learning curve to achieve technical competence and relevant outcomes. Moreover, there is no consensus on the learning process of ETSS. We aimed to review and determine the technical proficiency points of ETSS and discuss how to accelerate the learning curve.
Core databases, including PubMed, Embase, and the Cochrane Library, were systematically searched for learning curve studies that demonstrated the clinical outcomes and learning status of ETSS for pituitary adenomas using numerical data. Quality assessments of the included articles were performed using the Newcastle–Ottawa scale. The cutoff points were evaluated based on various outcome measures.
Eleven full-text articles, representing 2780 cases, were selected from 317 screened studies. The outcome measures were operative time, tumor removal, endocrinological results, visual field, and surgical complications. The plateaus or cutoff points in the learning curve varied with a mean of 103 ± 139.43 (range, 9–500) cases.
ETSS is an efficient and minimally invasive alternative surgical option for pituitary tumors. Plateau points may differ according to outcome measures, patient selection, training status, and surgical conditions. Therefore, great care should be taken when interpreting the learning curve. A systematic training program is essential to improve the learning process of endoscopic neurosurgical procedures.
Liquid electrolytes composed of lithium salt in a mixture of organic solvents have been widely used for lithium-ion batteries. However, the high flammability of the organic solvents can lead to ...thermal runaway and explosions if the system is accidentally subjected to a short circuit or experiences local overheating. In this work, a cross-linked composite gel polymer electrolyte was prepared and applied to lithium-ion polymer cells as a safer and more reliable electrolyte. Mesoporous SiO2 nanoparticles containing reactive methacrylate groups as cross-linking sites were synthesized and dispersed into the fibrous polyacrylonitrile membrane. They directly reacted with gel electrolyte precursors containing tri(ethylene glycol) diacrylate, resulting in the formation of a cross-linked composite gel polymer electrolyte with high ionic conductivity and favorable interfacial characteristics. The mesoporous SiO2 particles also served as HF scavengers to reduce the HF content in the electrolyte at high temperature. As a result, the cycling performance of the lithium-ion polymer cells with cross-linked composite gel polymer electrolytes employing methacrylate-functionalized mesoporous SiO2 nanoparticles was remarkably improved at elevated temperatures.
With the wide range of requirements for architectural glass, such as transparency, opacity, and hydrophobicity, there is a need to address the issues in the complexity of convention methods. Thus, ...considering functionality and applicability in various architectural windows, hydrophobic alumina/polytetrafluoroethylene (Al2O3/PTFE) composite layers with transparency or opacity were transferred to commercial architectural glass using a facile aerosol deposition (AD) process. We successfully fabricated hydrophobic coating layers with high transmittance (only a 0.03% difference from sheet glass) by optimizing the PTFE content in Al2O3 using solution‐based synthesized powders to enable a uniform surface topology. The opaque hydrophobic Al2O3/PTFE coating layers exhibit a transmittance of approximately 0% with excellent hydrophobicity of 130°. Remarkably, this opaque film was successfully employed onto a large deposition area, curved substrate, and micro‐patterned regions. It is believed that our AD‐prepared composite layers have great potential for architectural glass in terms of economic feasibility and versatility.
Airborne fungi are ubiquitous in the environment and are commonly associated with airway inflammatory diseases. The innate immune defense system eliminates most inhaled fungi. However, some influence ...the development of chronic rhinosinusitis. Fungal CRS is thought of as not a common disease, and its incidence increases over time. Fungi are present in CRS patients and in healthy sinonasal mucosa. Although the immunological mechanisms have not been entirely explained, CRS patients may exhibit different immune responses than healthy people against airborne fungi. Fungi can induce Th1 and Th2 immune responses. In CRS, Th2-related immune responses against fungi are associated with pattern recognition receptors in nasal epithelial cells, the production of inflammatory cytokines and chemokines from nasal epithelial cells, and interaction with innate type 2 cells, lymphocytes, and inflammatory cells. Fungi also interact with neutrophils and eosinophils and induce neutrophil extracellular traps (NETs) and eosinophil extracellular traps (EETs). NETs and EETs are associated with antifungal properties and aggravation of chronic inflammation in CRS by releasing intracellular granule proteins. Fungal and bacterial biofilms are commonly found in CRS and may support chronic and recalcitrant CRS infection. The fungal-bacterial interaction in the sinonasal mucosa could affect the survival and virulence of fungi and bacteria and host immune responses. The interaction between the mycobiome and microbiome may also influence the host immune response, impacting local inflammation and chronicity. Although the exact immunopathologic role of fungi in the pathogenesis of CRS is not completely understood, they contribute to the development of sinonasal inflammatory responses in CRS.
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