Mok-Hwa Kim

Facile Synthesis of Nb2O5@Carbon Core–Shell Nanocrystals with Controlled Crystalline Structure for High-Power Anodes in Hybrid Supercapacitors

Hybrid supercapacitors (battery-supercapacitor hybrid devices, HSCs) deliver high energy within seconds (excellent rate capability) with stable cyclability. One of the key limitations in developing high-performance HSCs is imbalance in power capability between the sluggish Faradaic lithium-intercalation anode and rapid non-Faradaic capacitive cathode. To solve this problem, we synthesize Nb2O5@carbon core-shell nanocyrstals (Nb2O5@C NCs) as high-power anode materials with controlled crystalline phases (orthorhombic (T) and pseudohexagonal (TT)) via a facile one-pot synthesis method based on a water-in-oil microemulsion system. The synthesis of ideal T-Nb2O5 for fast Li(+) diffusion is simply achieved by controlling the microemulsion parameter (e.g., pH control). The T-Nb2O5@C NCs shows a reversible specific capacity of ∼180 mA h g(-1) at 0.05 A g(-1) (1.1-3.0 V vs Li/Li(+)) with rapid rate capability compared to that of TT-Nb2O5@C and carbon shell-free Nb2O5 NCs, mainly due to synergistic effects of (i) the structural merit of T-Nb2O5 and (ii) the conductive carbon shell for high electron mobility. The highest energy (∼63 W h kg(-1)) and power (16 528 W kg(-1) achieved at ∼5 W h kg(-1)) densities within the voltage range of 1.0-3.5 V of the HSC using T-Nb2O5@C anode and MSP-20 cathode are remarkable.

The role of interleukin-17 in mouse models of atopic dermatitis and contact dermatitis.

Atopic dermatitis (AD) and contact dermatitis (CD) are both T cell‐mediated eczematous disorders. Interleukin (IL)‐17, expressed by T helper (Th)17 cells, is involved in recruitment of inflammatory cells into AD and CD skin.

Ribbon-like activated carbon with a multi-structure for supercapacitors

Ribbon-like activated carbon (RAC) has been successfully developed by a two-step activation process based on alkali activation and an electrochemical activation route. The multi-structure of the RAC features a porous graphitic structure with the coexistence of micropores and graphitic structures, mainly originating from the loose packing of the graphite sheets as a result of the degree of graphitization controlled by the carbonization conditions. RAC provides the tremendous benefits of excellent cycle life, high power (3.2 kW kg−1), and high energy density (43.5 W h kg−1) for electric double-layer capacitors, because of its graphitic architecture comprised of micropores and ring-shaped crystalline structures. In addition to investigating the improved electrochemical performance, we observed an interesting feature of the RAC: the obtained RAC has a high structural stability as shown by ex situ high-resolution transmission electron microscopy (HR-TEM). These extraordinary results are attributed to the unique structure of RAC.

Rational design of Li3VO4@carbon core–shell nanoparticles as Li-ion hybrid supercapacitor anode materials

A Li-ion hybrid supercapacitor (Li-HSC) delivering high energy within seconds (excellent rate performance) with stable cycle life is one of the most highly attractive energy storage devices. However, the limited anode materials for Li-HSC systems lead to stagnation and restrict the development of high-performance Li-HSCs. To tackle this problem, a facile synthetic route to Li3VO4@carbon core–shell nanoparticles (Li3VO4@C NPs), a promising high-power anode for Li-HSCs, is reported. The synthesized Li3VO4@C NPs show a high specific capacity of ∼400 mA h g−1 at the current density of 0.02 A g−1 in the potential range from 0.2 to 3.0 V (vs. Li/Li+), with rapid charge/discharge characteristics (∼110 mA h g−1 at 10 A g−1). By various electrochemical analyses, it was demonstrated that the excellent electrochemical properties of Li3VO4@C NPs stem from their improved pseudocapacitive behavior and their low internal resistance, which are mainly due to the synergistic effects of (i) a well-designed electrode morphology achieved by nano-engineering and (ii) the structural merits of a core–shell architecture. In addition, the Li-HSC using the Li3VO4@C NP anode and activated carbon (AC) cathode provides ∼190 W h kg−1 energy and ∼18 500 W kg−1 power density, with long-term cycle stability in the potential range from 0.0 to 4.3 V.

IgE cross-reactivity of peanut with walnut and soybean in children with food allergy.

BACKGROUND Peanut allergies are common and can be life-threating for sensitised individuals. Peanut allergens share significant amino acid homology with those of other legumes and tree nuts, but their cross-reactivity still remains unclear. OBJECTIVE We sought to determine the clinical significance of the cross-reactivity of peanut allergens with those of walnut and soybean. METHODS Pooled sera from eight subjects with both peanut and walnut specific IgE were investigated in an inhibition test. After the sera were incubated with either peanut or walnut protein extracts, the quantity of IgE antibodies against the peanut and walnut was measured using an immunoCAP test. Likewise, pooled sera from 18 subjects with both peanut and soybean specific IgE antibodies were incubated with either peanut or soybean protein extracts and evaluated with a peanut and soybean immunoCAP test. SDS-PAGE and immunoblotting were also performed with peanut, walnut and soybean protein extracts and relevant sera. RESULTS Peanut specific IgE was inhibited up to 20% and 26% by walnut and soybean protein extracts, respectively. In reverse, walnut and soybean specific IgE were inhibited up to 21% and 23% by peanut protein extracts, respectively. In the immunoblot analysis, pooled serum from the subjects with peanut specific IgE antibodies reacted with walnut protein extracts significantly. CONCLUSION Although the clinical significance of the cross-reactivity of peanut specific IgE with walnut and soybean protein extracts has not been established, we believe that individuals who are allergic to peanuts need to be cautious about consuming walnuts and soybeans.

Increased sputum levels of thymus and activation-regulated chemokine in children with asthma not eosinophilic bronchitis☆

BACKGROUND Thymus and activation-regulated chemokine (TARC), a member of the CC chemokine family, plays a crucial role in Th2-specific inflammation. We aimed to determine the concentration of sputum TARC in children with asthma and eosinophilic bronchitis (EB) and its relation with eosinophilic inflammation, pulmonary function, and bronchial hyper-responsiveness. METHODS In total, 90 children with asthma, 38 with EB, and 45 control subjects were enrolled. TARC levels were measured in sputum supernatants using an ELISA. We performed pulmonary function tests and measured exhaled fractional nitric oxide, eosinophil counts in blood, and sputum and serum levels of total IgE in all children. RESULTS Sputum TARC levels were significantly higher in children with asthma than in either children with EB (p=0.004) or the control subjects (p=0.014). Among patients with asthma, sputum TARC concentration was higher in children with sputum eosinophilia than in those without sputum eosinophilia (p=0.035). Sputum TARC levels positively correlated with eosinophil counts in sputum, serum total IgE levels, exhaled fractional nitric, and the bronchodilator response. Negative significant correlations were found between sputum TARC and FEV1/FVC (the ratio of forced expiratory volume in one second and forced expiratory vital capacity) or PC20 (the provocative concentration of methacholine causing a 20% decrease in the FEV1). CONCLUSION Elevated TARC levels in sputum were detected in children with asthma but not in children with EB. Sputum TARC could be a supportive marker for discrimination of asthma from EB in children showing characteristics of eosinophilic airway inflammation.

Lithium–Sulfur Capacitors

Although many existing hybrid energy storage systems demonstrate promising electrochemical performances, imbalances between the energies and kinetics of the two electrodes must be resolved to allow their widespread commercialization. As such, the development of a new class of energy storage systems is a particular challenge, since future systems will require a single device to provide both a high gravimetric energy and a high power density. In this context, we herein report the design of novel lithium-sulfur capacitors. The resulting asymmetric systems exhibited energy densities of 23.9-236.4 Wh kg-1 and power densities of 72.2-4097.3 W kg-1, which are the highest reported values for an asymmetric system to date. This approach involved the use of a prelithiated anode and a hybrid cathode material exhibiting anion adsorption-desorption in addition to the electrochemical reduction and oxidation of sulfur at almost identical rates. This novel strategy yielded both high energy and power densities, and therefore establishes a new benchmark for hybrid systems.