15 research outputs found

    A cooperative biphasic MoOx–MoPx promoter enables a fast-charging lithium-ion battery

    Get PDF
    The realisation of fast-charging lithium-ion batteries with long cycle lifetimes is hindered by the uncontrollable plating of metallic Li on the graphite anode during high-rate charging. Here we report that surface engineering of graphite with a cooperative biphasic MoOx–MoPx promoter improves the charging rate and suppresses Li plating without compromising energy density. We design and synthesise MoOx–MoPx/graphite via controllable and scalable surface engineering, i.e., the deposition of a MoOx nanolayer on the graphite surface, followed by vapour-induced partial phase transformation of MoOx to MoPx. A variety of analytical studies combined with thermodynamic calculations demonstrate that MoOx effectively mitigates the formation of resistive films on the graphite surface, while MoPx hosts Li+ at relatively high potentials via a fast intercalation reaction and plays a dominant role in lowering the Li+ adsorption energy. The MoOx–MoPx/graphite anode exhibits a fast-charging capability (<10 min charging for 80% of the capacity) and stable cycling performance without any signs of Li plating over 300 cycles when coupled with a LiNi0.6Co0.2Mn0.2O2 cathode. Thus, the developed approach paves the way to the design of advanced anode materials for fast-charging Li-ion batteries. © 2021, The Author(s).1

    East Asian specific asthma associated variants were discovered via exome-sequencing

    No full text
    Rapid development in sequencing technology enabled us study a near complete catalogue of variants in human genome. We performed whole-exome sequencing to identify functional variants responsible for severe asthma in Korean population. We identified 10 variants of 6 candidate asthma genes (P < 10(-5)) comprising GPR88, AGTRAP, GTP2IRD1, KANK1, DNHD1, and DCUN1D2. Our study provides possible new therapeutic targets for asthma.N

    Clonal Dissemination and mupA Gene Polymorphism of Mupirocin-Resistant Staphylococcus aureus Isolates from Long-Term-Care Facilities in South Korea

    No full text
    We identified 25 high-level mupirocin-resistant (MuH) and 21 low-level mupirocin-resistant (MuL) Staphylococcus aureus isolates from eight long-term-care facilities (LTCFs). The pulsed-field gel electrophoresis patterns of 19 MuH and 19 MuL isolates from two facilities were identical for 18 and 15 isolates, respectively. The most predominant mupA restriction fragment length polymorphism type was found in 21 MuH isolates. We conclude that clonal transmission of MuH and MuL S. aureus strains occurred in these LTCFs. This is the first report of clonal transfer of mupirocin resistance in LTCFs

    Effect of Electrolytes on Electrochemical Properties of Magnesium Electrodes

    No full text
    Magnesium (Mg) deposition and dissolution behaviors of 0.2 M MgBu2(AlCl2Et)2MgBu_2-(AlCl_2Et)_2, 0.5 M Mg(ClO4)2Mg(ClO_4)_2, and 0.4M (PhMgCl)2AlCl3(PhMgCl)_2-AlCl_3-based electrolytes with and without tris(pentafluorophenyl) borane (TPFPB) are investigated by ex situ scanning electron microscopy (SEM) and galvanostatic cycling of Mg/copper (Cu) cells. To ascertain the factors responsible for the anodic stability of the electrolytes, linear sweep voltammogrametry (LSV) experiments for various electrolytes and solvents are conducted. The effects of TPFPB as an additive on the anodic stability of 0.4M ((PhMgCl)2AlCl3(PhMgCl)_2-AlCl_3/THF electrolyte are also discussed.close

    Role of Cu in Mo6S8 and Cu mixture cathodes for magnesium ion batteries

    No full text
    The reversible capacity of Chevrel Mo6S8 cathode can be increased by the simple addition of the Cu metal to Mo6S8 electrodes. However, the exact reaction mechanism of the additional reversible capacity for the Mo6S8 and Cu mixture cathode has not been clearly understood yet. To clarify this unusual behavior, we synthesize a novel Cu nanoparticle/graphene composite for the preparation of the mixture electrode. We thoroughly investigate the electrochemical behaviors of the Mo6S8 and Cu mixture cathode with the relevant structural verifications during Mg2+ insertion and extraction. The in situ formation of CuxMo(6)S(8) is observed, indicating the spontaneous electrochemical insertion of Cu to the Mo6S8 host from the Cu nanoparticle/graphene composite. The reversible electrochemical replacement reaction of Cu in the Mo6S8 structure is clarified with the direct evidence for the solid state Cu deposition/dissolution at the surface of Mo6S8 particles. Moreover, the Mo6S8 and Cu mixture cathode improves the rate capability compared to the pristine. We believe that our finding will contribute to understanding the origin of the additional capacity of the Mo6S8 cathode arising from Cu addition and improve the electrochemical performance of the Mo6S8 cathode for rechargeable Mg batteries

    Magnesium(II) Bis(trifluoromethane sulfonyl) Imide-Based Electrolytes with Wide Electrochemical Windows for Rechargeable Magnesium Batteries

    No full text
    We present a promising electrolyte candidate, Mg­(TFSI)<sub>2</sub> dissolved in glyme/diglyme, for future design of advanced magnesium (Mg) batteries. This electrolyte shows high anodic stability on an aluminum current collector and allows Mg stripping at the Mg electrode and Mg deposition on the stainless steel or the copper electrode. It is clearly shown that nondendritic and agglomerated Mg secondary particles composed of ca. 50 nm primary particles alleviating safety concern are formed in glyme/diglyme with 0.3 M Mg­(TFSI)<sub>2</sub> at a high rate of 1C. Moreover, a Mg­(TFSI)<sub>2</sub>-based electrolyte presents the compatibility toward a Chevrel phase Mo<sub>6</sub>S<sub>8</sub>, a radical polymer charged up to a high voltage of 3.4 V versus Mg/Mg<sup>2+</sup> and a carbon–sulfur composite as cathodes

    Role of Cu in Mo<sub>6</sub>S<sub>8</sub> and Cu Mixture Cathodes for Magnesium Ion Batteries

    No full text
    The reversible capacity of Chevrel Mo<sub>6</sub>S<sub>8</sub> cathode can be increased by the simple addition of the Cu metal to Mo<sub>6</sub>S<sub>8</sub> electrodes. However, the exact reaction mechanism of the additional reversible capacity for the Mo<sub>6</sub>S<sub>8</sub> and Cu mixture cathode has not been clearly understood yet. To clarify this unusual behavior, we synthesize a novel Cu nanoparticle/graphene composite for the preparation of the mixture electrode. We thoroughly investigate the electrochemical behaviors of the Mo<sub>6</sub>S<sub>8</sub> and Cu mixture cathode with the relevant structural verifications during Mg<sup>2+</sup> insertion and extraction. The <i>in situ</i> formation of Cu<sub><i>x</i></sub>Mo<sub>6</sub>S<sub>8</sub> is observed, indicating the spontaneous electrochemical insertion of Cu to the Mo<sub>6</sub>S<sub>8</sub> host from the Cu nanoparticle/graphene composite. The reversible electrochemical replacement reaction of Cu in the Mo<sub>6</sub>S<sub>8</sub> structure is clarified with the direct evidence for the solid state Cu deposition/dissolution at the surface of Mo<sub>6</sub>S<sub>8</sub> particles. Moreover, the Mo<sub>6</sub>S<sub>8</sub> and Cu mixture cathode improves the rate capability compared to the pristine. We believe that our finding will contribute to understanding the origin of the additional capacity of the Mo<sub>6</sub>S<sub>8</sub> cathode arising from Cu addition and improve the electrochemical performance of the Mo<sub>6</sub>S<sub>8</sub> cathode for rechargeable Mg batteries

    Analysis of Changes in Gene Expression and Metabolic Profiles Induced by Silica-Coated Magnetic Nanoparticles

    No full text
    Magnetic nanoparticles (MNPs) have proven themselves to be useful in biomedical research; however, previous reports were insufficient to address the potential dangers of nanoparticles. Here, we investigated gene expression and metabolic changes based on the microarray and gas chromatography–mass spectrometry with human embryo kidney 293 cells treated with MNPs@SiO<sub>2</sub>(RITC), a silica-coated MNP containing Rhodamine B isothiocyanate (RITC). In addition, measurement of reactive oxygen species (ROS) and ATP analysis were performed to evaluate the effect of MNPs@SiO<sub>2</sub>(RITC) on mitochondrial function. Compared to the nontreated control, glutamic acid was increased by more than 2.0-fold, and expression of genes related to the glutamic acid metabolic pathway was also disturbed in 1.0 μg/μL of MNPs@SiO<sub>2</sub>(RITC)-treated cells. Furthermore, increases in ROS concentration and mitochondrial damage were observed in this MNPs@SiO<sub>2</sub>(RITC) concentration. The organic acids related to the Krebs cycle were also disturbed, and the capacity of ATP synthesis was decreased in cell treated with an overdose of MNPs@SiO<sub>2</sub>(RITC). Collectively, these results suggest that overdose (1.0 μg/μL) of MNPs caused transcriptomic and metabolic disturbance. In addition, we suggest that a combination of gene expression and metabolic profiles will provide more detailed and sensitive toxicological evaluation for nanoparticles

    Korean childhood asthma study (KAS): a prospective, observational cohort of Korean asthmatic children

    Get PDF
    Abstract Background Asthma is a syndrome composed of heterogeneous disease entities. Although it is agreed that proper asthma endo-typing and appropriate type-specific interventions are crucial in the management of asthma, little data are available regarding pediatric asthma. Methods We designed a cluster-based, prospective, observational cohort study of asthmatic children in Korea (Korean childhood Asthma Study [KAS]). A total of 1000 Korean asthmatic children, aged from 5 to 15 years, will be enrolled at the allergy clinics of the 19 regional tertiary hospitals from August 2016 to December 2018. Physicians will verify the relevant histories of asthma and comorbid diseases, as well as airway lability from the results of spirometry and bronchial provocation tests. Questionnaires regarding subjects’ baseline characteristics and their environment, self-rating of asthma control, and laboratory tests for allergy and airway inflammation will be collected at the time of enrollment. Follow-up data regarding asthma control, lung function, and environmental questionnaires will be collected at least every 6 months to assess outcome and exacerbation-related aggravating factors. In a subgroup of subjects, peak expiratory flow rate will be monitored by communication through a mobile application during the overall study period. Cluster analysis of the initial data will be used to classify Korean pediatric asthma patients into several clusters; the exacerbation and progression of asthma will be assessed and compared among these clusters. In a subgroup of patients, big data-based deep learning analysis will be applied to predict asthma exacerbation. Discussion Based on the assumption that asthma is heterogeneous and each subject exhibits a different subset of risk factors for asthma exacerbation, as well as a different disease progression, the KAS aims to identify several asthma clusters and their essential determinants, which are more suitable for Korean asthmatic children. Thereafter we may suggest cluster-specific strategies by focusing on subjects’ personalized aggravating factors during each exacerbation episode and by focusing on disease progression. The KAS will provide a good academic background with respect to each interventional strategy to achieve better asthma control and prognosis
    corecore