The self‐organization of organic polymer semiconductors into ordered supramolecular assemblies commensurate with efficient charge transport is achieved by tuning a range of process parameters (e.g., film deposition method (spin vs drop cast), solvent boiling point (low vs high boiling point), polymer‐dielectric interface treatment, and post‐deposition processing (solvent vapor or thermal annealing)). However, these strategies present limitations for large‐scale high‐throughput processing due to associated pre‐ and/or post semiconductor deposition steps. Here, photoinduced anisotropic supramolecular assembly of P3HT chains in solution is demonstrated. UV irradiation provides for enhanced intramolecular ordering of solubilized polymer chains, and thereby effects formation of anisotropic supramolecular polymer assemblies via favorable π–π stacking (intermolecular interaction). Molecular ordering is thus dramatically enhanced with concomitant, enhanced charge transport characteristics of corresponding films. Additional pre‐ and/or post treatments are avoided.
Capacitive deionization (CDI) that engages porous carbon electrodes constitutes one of the well-established energy-efficient desalination methods. However, improvement in desalination performance, including ion removal capacity, ion removal rate, and charge efficiency remains requisite for a wide range of applications. Herein, an ion-exchange membrane-free asymmetric CDI is introduced by pairing a metal organic framework (MOF), namely, K 0.03 Cu[Fe(CN) 6 ] 0.65 ·0.43H 2 O and porous carbon. The exclusive intercalation of cations into the MOF prevents the reverse adsorption of co-ions (anions), thus significantly improving ion removal capacity (23.2 mg g −1 ) and charge efficiency (75.8%). Moreover, by utilizing the advantage of the MOF that diverse mono-and divalent cations can be stored in the narrow redox potential range, the asymmetric CDI allows simultaneous capture of monoand divalent cations, thus achieving omnivalent cation removal. Moreover, cations are intercalated in the hydrated forms without a discrete phase transition of the host structure, facilitating rapid desalination by reducing the desolvation energy penalty, which results in a high ion removal rate of 0.24 mg g −1 s −1 . This study offers a new design principle in CDI: the integration of a crystal structure with large ionic channels that enable hydrated intercalation of multivalent ions in a fast and exclusive manner.
PurposeTo determine the impact of noise on heart rate variability (HRV) in men, with a focus on the noise type rather than on noise intensity.Materials and MethodsForty college-going male volunteers were enrolled in this study and were randomly divided into four groups according to the type of noise they were exposed to: background, traffic, speech, or mixed (traffic and speech) noise. All groups except the background group (35 dB) were exposed to 45 dB sound pressure levels. We collected data on age, smoking status, alcohol consumption, and disease status from responses to self-reported questionnaires and medical examinations. We also measured HRV parameters and blood pressure levels before and after exposure to noise. The HRV parameters were evaluated while patients remained seated for 5 minutes, and frequency and time domain analyses were then performed.ResultsAfter noise exposure, only the speech noise group showed a reduced low frequency (LF) value, reflecting the activity of both the sympathetic and parasympathetic nervous systems. The low-to-high frequency (LF/HF) ratio, which reflected the activity of the autonomic nervous system (ANS), became more stable, decreasing from 5.21 to 1.37; however, this change was not statistically significant.ConclusionThese results indicate that 45 dB(A) of noise, 10 dB(A) higher than background noise, affects the ANS. Additionally, the impact on HRV activity might differ according to the noise quality. Further studies will be required to ascertain the role of noise type.
The anisotropic assembly of P3HT nanocrystallites into longer nanofibrillar structures was demonstrated via sequential UV irradiation after ultrasonication to the pristine polymer solutions. The morphology of resultant films was studied by atomic force microscopy (AFM), and quantitative analysis of intra- and intermolecular ordering of polymer chains was performed by means of static absorption spectroscopy and quantitative modeling. Consequently, the approach to treat the precursor solution enhanced intra- and intermolecular ordering and reduced the incidence of grain boundaries within P3HT films, which contributed to the excellent charge carrier transport characteristics of the corresponding films (μ ≈ 12.0 × 10(-2) cm(2) V(-1) s(-1) for 96% RR P3HT).
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is considered as the most significant global public health crisis of the century. Several drug candidates have been suggested as potential therapeutic options for COVID-19, including remdesivir, currently the only authorized drug for use under an Emergency Use Authorization. However, there is only limited information regarding the safety profiles of the proposed drugs, in particular drug-induced cardiotoxicity. Here, we evaluated the antiviral efficacy and cardiotoxicity of remdesivir using cardiomyocytes-derived from human pluripotent stem cells (hPSC-CMs) as an alternative source of human primary cardiomyocytes (CMs). In this study, remdesivir exhibited up to 60-fold higher antiviral activity in hPSC-CMs compared to Vero E6 cells; however, it also induced moderate cardiotoxicity in these cells. To gain further insight into the drug-induced arrhythmogenic risk, we assessed QT interval prolongation and automaticity of remdesivir-treated hPSC-CMs using a multielectrode array (MEA). As a result, the data indicated a potential risk of QT prolongation when remdesivir is used at concentrations higher than the estimated peak plasma concentration. Therefore, we conclude that close monitoring of the electrocardiographic/QT interval should be advised in SARS-CoV-2-infected patients under remdesivir medication, in particular individuals with pre-existing heart conditions.
This paper presents our extensive investigation of the security aspects of control plane procedures based on dynamic testing of the control components in operational Long Term Evolution (LTE) networks. For dynamic testing in LTE networks, we implemented a semi-automated testing tool, named LTEFuzz, by using open-source LTE software over which the user has full control. We systematically generated test cases by defining three basic security properties by closely analyzing the standards. Based on the security property, LTEFuzz generates and sends the test cases to a target network, and classifies the problematic behavior by only monitoring the device-side logs. Accordingly, we uncovered 36 vulnerabilities, which have not been disclosed previously. These findings are categorized into five types: Improper handling of (1) unprotected initial procedure, (2) crafted plain requests, (3) messages with invalid integrity protection, (4) replayed messages, and (5) security procedure bypass. We confirmed those vulnerabilities by demonstrating proof-of-concept attacks against operational LTE networks. The impact of the attacks is to either deny LTE services to legitimate users, spoof SMS messages, or eavesdrop/manipulate user data traffic. Precise root cause analysis and potential countermeasures to address these problems are presented as well. Cellular carriers were partially involved to maintain ethical standards as well as verify our findings in commercial LTE networks.
Capacitive deionization (CDI) has received much attention, which is considered as a promising electrochemical water desalination technology. However, an obstacle to its conventional application is the limited ion removal capacity of carbon electrodes induced by the electrical double layer. Here, a novel CDI system, called multichannel redox CDI (MC-RCDI), was proposed to enhance the desalination performance of CDI by utilizing the redox couple of ferricyanide/ferrocyanide as well as the adsorption capacity of the conventional carbon electrodes. In the MC-RCDI, the feed water in the middle channel was fully separated from the redox couple-containing electrolyte in the side channel by ion exchange membranes. Then, along with the carbon adsorption capacity, the electrochemically reversible redox reaction provided an additional salt removal capacity driven by the charge inequality. Thus, the MC-RCDI exhibited a significantly enhanced salt adsorption capacity (SAC) of 67.8 mg/g (8.59 μmol/J) and a charge efficiency of ∼90%. The results demonstrated as greater than threefold increase in the salt removal capacity, compared to the system without the redox reaction (SAC ≈ 19.9 mg/g, 7.50 μmol/J). Moreover, in the MC-RCDI system, a sustainable redox reaction allowed a continuous desalination without a discharging step, possibly leading to the desalination of concentrated feed solution, up to seawater level standards.
A critical problem with stretchable supercapacitors developed to date has been evaporation of a volatile component of their electrolyte, causing failure. In this work, we demonstrated successful use of an ionic-liquid-based nonvolatile gel (ion-gel) electrolyte in carbon nanotube (CNT)-based stretchable supercapacitors. The CNT/ion-gel supercapacitors showed high capacitance retention (96.6%) over 3000 stretch cycles at 20% strain. The high durability against stretch cycles was achieved by introducing microroughness at the interfaces between different materials. The microroughness was produced by the simple process of imprinting the surface microstructure of office paper onto a poly(dimethylsiloxane) substrate; the surface texture is reproduced in successive current collector and CNT layers. Adhesion between the different layers was strengthened by this roughness and prevented delamination over repeated stretch cycles. The addition of a CNT layer decreased the sensitivity of electrical characteristics to stretching. Moreover, the ion-gel increases the operating voltage window (3 V) and hence the energy density. We believe our demonstration will greatly contribute to the development of flexible and/or stretchable energy-storage devices with high durability.
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