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Yarn-type supercapacitors should have high energy density in small given spaces, and the one attempt among many is to comprise the electrodes asymmetrically. However, the low capacitance of conventional materials causes the widened operating voltage useless. In this study, we have utilized a novel material MXene with carbon nanotubes (CNTs) to make highly loaded MXene/CNT yarn electrodes, which exhibited a remarkable areal capacitance. With MnO2/CNT biscrolled cathode and PVA/LiCl gel electrolyte, the plied asymmetric yarn supercapacitor had energy density of 100 µWh/cm2. The yarn supercapacitor could operate under mechanical deformations without performance degradation.
We trace Sn nanoparticles (NPs) produced from SnO2 nanotubes (NTs) during lithiation initialized by high energy e-beam irradiation. The growth dynamics of Sn NPs is visualized in liquid electrolytes by graphene liquid cell transmission electron microscopy. The observation reveals that Sn NPs grow on the surface of SnO2 NTs via coalescence and the final shape of agglomerated NPs is governed by surface energy of the Sn NPs and the interfacial energy between Sn NPs and SnO2 NTs. Our result will likely benefit more rational material design of the ideal interface for facile ion insertion.
Social media data are a highly contextual health information source. The objective of this study was to identify Korean keywords for detecting influenza epidemics from social media data.
We included data from Twitter and online blog posts to obtain a sufficient number of candidate indicators and to represent a larger proportion of the Korean population. We performed the following steps: initial keyword selection; generation of a keyword time series using a preprocessing approach; optimal feature selection; model building and validation using least absolute shrinkage and selection operator, support vector machine (SVM), and random forest regression (RFR).
A total of 15 keywords optimally detected the influenza epidemic, evenly distributed across Twitter and blog data sources. Model estimates generated using our SVM model were highly correlated with recent influenza incidence data.
The basic principles underpinning our approach could be applied to other countries, languages, infectious diseases, and social media sources. Social media monitoring using our approach may support and extend the capacity of traditional surveillance systems for detecting emerging influenza. (Disaster Med Public Health Preparedness. 2018; 12: 352–359)
Social support programs for dementia caregivers were widely used in order to reduce care burden. We investigated which types of social supports can reduce psychological and non-psychological burdens of dementia caregivers, and explored the mechanism of those social supports.
We evaluated 731 community-dwelling dementia patients and their caregivers from the National Survey of Dementia Care in South Korea. We investigated the five types of social supports (emotional support, informational support, tangible support, positive social interaction, affectionate support) using the Medical Outcomes Study Social Support Survey in each caregiver. The mechanisms of specific types of social support on psychological/non-psychological burden were examined using path analysis.
Positive social interaction and affectionate support reduced psychological burden via direct and indirect paths. Tangible support reduced the non-psychological burden via direct and indirect paths. Informational support and emotional support were not helpful for reducing psychological or non-psychological burden. A maximum of 20% of psychological burden could be relieved by positive social interaction and 10.3% of that could be reduced by affectionate support. Tangible support was associated with a 15.1% maximal improvement in non-psychological burden.
In order to reduce caregiver burden in dementia effectively, psychosocial interventions should be tailored to target type of caregiver burden.
Copper–zinc alloy (Cu/Zn) powders with different Zn to Cu molar ratios were prepared by the combustion synthesis technique using a CuO + 0.15(C2H4)n + kZn (0.2 ≤ k ≤ 1.6 mol) reactive mixture. Depending on the Zn concentration, the combustion wave developed a temperature between 950 and 1040 °C and passed through the sample with a speed of 0.04–0.08 cm/s, resulting in almost single-stage temperature distributions. Cu/Zn alloy powders with Zn concentrations ranging from 0.5 to 45 wt% were obtained. It was shown that alloy particles become spherical and well dispersed with increasing Zn concentration. Inert dilution test with KCl salt was also performed to determine the influence of temperature degradation in the combustion wave on the morphology and composition of alloy powders.
Porous zirconium metal microspheres were synthesized successfully by a combustion technique using ZrO2 + 2Mg starting mixture. In this process, a controlled amount of KClO3 + 3Mg is mixed with ZrO2 + 2Mg to enable a self-sustaining combustion process and to promote a reduction of the ZrO2. The framework structure, morphology, and porosity of zirconium microspheres were determined using various techniques. Microscopic visualization suggested that the spherical structure has macroporous windows of diameter ∼0.5–5.0 μm and the space between the macropores has a wormhole-like mesoporous/microporous structure. The mesoporous structure had a pore diameter of ∼1.19 nm. This procedure provides an easy method for the synthesis of porous microspherical assemblies of Zr composed of submicrometer size particles.
Mesoporous low dielectric poly(silsesquioxane) thin films have been fabricated by templating various surfactants such as cetyltrimethyl ammonium bromide (CTAB) or 4-octylphenol polyethoxylate (OPE) in the silsesquioxane polymer matrix and their properties of the thin films characterized by electrical, mechanical and structural characterization. Depending on the types of the surfactants, mesoporous poly(silsesquioxane) thin films with different porosities have been formed. The dielectric constant (k) of the films depended on the content or porosity of the surfactants. The dielectric constants of ca. 2.2–2.4 were obtained for the films with relative porosities of about 15–30 vol. % to the polymer matrix itself. The elastic modulus of the films showed a dependency on the type, content of the surfactants and was ca. 2.9 GPa with the k value of ca. 2.38.
A nano-thin TiO2 layer was uniformly coated on spherical Ni particles for applications in multilayer ceramic capacitors via a controlled hydrolysis process using TiCl4, (C2H5)2NH (diethylamine, DEA), and C4H9OH as Ti-source, gradual (OH)- former, and solvent, respectively. At the constant [DEA]/[TiCl4] =10.6, the Ti-hydroxide could be coated uniformly using the dilute source solution ([TiCl4] ≤ 0.2 M) while the Ti-hydroxide powder in a separated form was frequently observed at [TiCl4] ≥ 0.4 M. A uniform coating was attained at the slower precipitation, and the kinetics of precipitation was controlled by tuning the trace amount of water in the solution. The TiO2-coating not only prevented Ni oxidation but also retarded the sintering between the Ni particles to a large extent.
The purpose of this study was to evaluate the effects of botulinum toxin A (BTX-A, Botox) dilution volume and post-injection exercise with electrical stimulation on muscle paralysis. We injected 10 units of BTX-A diluted with 0.1 ml (B1, n=8) or 0.5 ml (B5, n=8) normal saline into both gastrocnemius muscles of 16 New Zealand white rabbits; two controls received no BTX-A. After BTX-A injection, all rabbits received calf muscle stretching exercise and electrical stimulation for 2 hours on the left leg. The compound muscle action potential (CMAP) decrease was most pronounced at 1 week and progressive recovery was observed (i.e. recovery from paralysis, increase of CMAP). There was a significant decrease of CMAP amplitudes in the B5 group compared with the B1 group at week 1 and week 4 (p<0.001). Left limbs with stretching exercise and electrical stimulation showed lower CMAP amplitudes compared with control right limbs of all rabbits. To maximize the muscle paralysis effect of BTX-A, increasing dilution volume and performing post-injection stretching exercise with electrical stimulation may be a promising strategy for increasing the beneficial effect of BTX-A treatment. Future studies are needed to investigate the clinical application of this finding.
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