Tuning Two Interfaces with Fluoroethylene Carbonate Electrolytes for High-Performance Li/LCO Batteries.

Various electrolytes have been reported to enhance the reversibility of Li-metal electrodes. However, for these electrolytes, concurrent and balanced control of Li-metal and positive electrode interfaces is a critical step toward fabrication of high-performance Li-metal batteries. Here, we report the tuning of Li-metal and lithium cobalt oxide (LCO) interfaces with fluoroethylene carbonate (FEC)-containing electrolytes to achieve high cycling stability of Li/LCO batteries. Reversibility of the Li-metal electrode is considerably enhanced for electrolytes with high FEC contents, confirming the positive effect of FEC on the stabilization of the Li-metal electrode. However, for FEC contents of 50 wt % and above, the discharge capacity is significantly reduced because of the formation of a passivation layer on the LCO cathodes. Using balanced tuning of the two interfaces, stable cycling over 350 cycles at 1.5 mA cm-2 is achieved for a Li/LCO cell with the 1 M LiPF6 FEC/DEC = 30/70 electrolyte. The enhanced reversibility of the Li-metal electrode is associated with the formation of LiF and polycarbonate in the FEC-derived solid electrolyte interface (SEI) layer. In addition, electrolytes with high FEC contents lead to lateral Li deposition on the sides of Li deposits and larger dimensions of rodlike Li deposits, suggesting the elastic and ion-conductive nature of the FEC-derived SEI layer.

Rational Design of Highly Packed, Crack-Free Sulfur Electrodes by Scaffold-Supported Drying for Ultrahigh-Sulfur-Loaded Lithium-Sulfur Batteries.

Despite the notable progress in the development of rechargeable lithium-sulfur batteries over the last decade, achieving high performance with high-sulfur-loaded sulfur cathodes remains a key challenge on the path to the commercialization of practical lithium-sulfur batteries. This paper presents a novel method by which to fabricate a crack-free sulfur electrode with an ultrahigh sulfur loading (16 mg cm-2) and a high sulfur content (64%). By introducing a porous scaffold on the top of a cast of sulfur cathode slurry, the formation of cracks during the drying of the cast can be prevented due to the lower volume shrinkage of the skin. The scaffold-supported sulfur cathode delivers a notably high capacities of 10.3 mAh cm-2 and 473 mAh cm-3 after a prolonged cycle, demonstrating that the crack-free structure renders more uniform redox reactions at such high sulfur loading. The highly packed, crack-free feature of the sulfur cathode is advantageous, given that it reduces the electrolyte uptake to as low as an E/S ratio of 4 µL mg-1, which additionally contributes to the high energy density. Therefore, the scaffold-supported drying fabrication method as presented here provides an effective route by which to design practically viable, energy-dense lithium-sulfur batteries.

Achieving three-dimensional lithium sulfide growth in lithium-sulfur batteries using high-donor-number anions.

Uncontrolled growth of insulating lithium sulfide leads to passivation of sulfur cathodes, which limits high sulfur utilization in lithium-sulfur batteries. Sulfur utilization can be augmented in electrolytes based on solvents with high Gutmann Donor Number; however, violent lithium metal corrosion is a drawback. Here we report that particulate lithium sulfide growth can be achieved using a salt anion with a high donor number, such as bromide or triflate. The use of bromide leads to ~95 % sulfur utilization by suppressing electrode passivation. More importantly, the electrolytes with high-donor-number salt anions are notably compatible with lithium metal electrodes. The approach enables a high sulfur-loaded cell with areal capacity higher than 4 mA h cm-2 and high sulfur utilization ( > 90 %). This work offers a simple but practical strategy to modulate lithium sulfide growth, while conserving stability for high-performance lithium-sulfur batteries.

An Ultrahigh Capacity Graphite/Li2S Battery with Holey-Li2S Nanoarchitectures.

The pairing of high-capacity Li2S cathode (1166 mAh g-1) and lithium-free anode (LFA) provides an unparalleled potential in developing safe and energy-dense next-generation secondary batteries. However, the low utilization of the Li2S cathode and the lack of electrolytes compatible to both electrodes are impeding the development. Here, a novel graphite/Li2S battery system, which features a self-assembled, holey-Li2S nanoarchitecture and a stable solid electrolyte interface (SEI) on the graphite electrode, is reported. The holey structure on Li2S is beneficial in decomposing Li2S at the first charging process due to the enhanced Li ion extraction and transfer from the Li2S to the electrolyte. In addition, the concentrated dioxolane (DOL)-rich electrolyte designed lowers the irreversible capacity loss for SEI formation. By using the combined strategies, the graphite/holey-Li2S battery delivers an ultrahigh discharge capacity of 810 mAh g-1 at 0.1 C (based on the mass of Li2S) and of 714 mAh g-1 at 0.2 C. Moreover, it exhibits a reversible capacity of 300 mAh g-1 after a record lifecycle of 600 cycles at 1 C. These results suggest the great potential of the designed LFA/holey-Li2S batteries for practical use.

Enhancing the Cycling Stability of Sodium Metal Electrodes by Building an Inorganic-Organic Composite Protective Layer.

Owing to the natural abundance of sodium resources and their low price, next-generation batteries employing an Na metal anode, such as Na-O2 and Na-S systems, have attracted a great deal of interest. However, the poor reversibility of an Na metal electrode during repeated electrochemical plating and stripping is a major obstacle to realizing rechargeable sodium metal batteries. It mainly originates from Na dendrite formation and exhaustive electrolyte decomposition due to the high reactivity of Na metal. Herein, we report a free-standing composite protective layer (FCPL) for enhancing the reversibility of an Na metal electrode by mechanically suppressing Na dendritic growth and mitigating the electrolyte decomposition. A systematic variation of the liquid electrolyte uptake of FCPL verifies the existence of a critical shear modulus for suppressing Na dendrite growth, being in good agreement with a linear elastic theory, and emphasizes the importance of the ionic conductivity of FCPL for attaining uniform Na plating and stripping. The Na-Na symmetric cell with an optimized FCPL exhibits a cycle life two times longer than that of a bare Na electrode.

The potential of minor ginsenosides isolated from the leaves of Panax ginseng as inhibitors of melanogenesis.

Three minor ginsenosides, namely, ginsenoside Rh6 (1), vina-ginsenoside R4 (2) and vina-ginsenoside R13 (3), were isolated from the leaves of hydroponic Panax ginseng. The chemical structures were determined based on spectroscopic methods, including fast atom bombardment mass spectroscopy (FAB-MS), 1D-nuclear magnetic resonance (NMR), 2D-NMR, and, infrared (IR) spectroscopy. The melanogenic inhibitory activity of compounds 1, 2 and 3 was 23.9%, 27.8% and 35.2%, respectively, at a concentration of 80 µM. Likewise, the three compounds showed inhibitory activity on body pigmentation on a zebrafish model, which is commonly used as a model for biomedical or cosmetic research. These results from in vitro and in vivo systems suggest that the three aforementioned compounds isolated from Panax ginseng may have potential as new skin whitening compounds.

Perfluorinated ionomer-enveloped sulfur cathodes for lithium-sulfur batteries.

Nafion is known to suppress the polysulfide (PS) shuttle effect, a major obstacle to achieving high capacity and long cycle life for lithium-sulfur batteries. However, elaborate control of the layer's configuration is required for high performance. In this regard, we designed a Nafion-enveloped sulfur cathode, where the Nafion layer is formed on the skin of the cathode, covering its surface and edge while not restricting the porosity. Discharge capacity and efficiency were enhanced with the enveloping configuration, demonstrating suppression of shuttle. The edge protection exhibited better cycling stability than an edge-open configuration. In the absence of the Nafion envelope, charged sulfur concentrated on the top region of the cathode because of the relatively lower PS concentration at the cathode surface. Surprisingly, for the Nafion-enveloped cathode, sulfur was evenly distributed along the cathode, indicating that the configuration imparts a uniform PS concentration within the cathode.

Quality evaluation of Panax ginseng roots using a rapid resolution LC-QTOF/MS-based metabolomics approach.

Korean ginseng (Panax ginseng C.A. Meyer) contains several types of ginsenosides, which are considered the major active medicinal components of ginseng. The types and quantities of ginsenosides found in ginseng may differ, depending on the location of cultivation, making it necessary to establish a reliable method for distinguishing cultivation locations of ginseng roots. P. ginseng roots produced in different regions of Korea, China, and Japan have been unintentionally confused in herbal markets owing to their complicated plant sources. PCA and PLS-DA using RRLC-QTOF/MS data was able to differentiate between ginsengs cultivated in Korea, China, and Japan. The chemical markers accountable for such variations were identified through a PCA loadings plot, tentatively identified by RRLC-QTOF/MS and partially verified by available reference standards. The classification result can be used to identify P. ginseng origin.

Anti-inflammatory cycloartane-type saponins of Astragalus membranaceus.

A new cycloartane-type triterpene glycoside, agroastragaloside V (1) was isolated from the roots of Astragalus membranaceus. The structure was identified as 3-O-ß-(2'-O-acetyl)-D-xylopyranosyl-6-O-ß-D-glucopyranosyl-(24S)-3ß,6α,24α,25-tetrahydroxy- 9,19-cyclolanostane, by means of spectroscopic methods, including HR-FAB/MS, 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. Four known cycloartane glycosides, namely, agroastragaloside I (2), agroastragaloside II (3), isoastragaloside II (4) and astragaloside IV (5) were also isolated. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.

Brazilin inhibits growth and induces apoptosis in human glioblastoma cells.

Brazilin, isolated from the methanol extract of the heart wood of Caesalpinia sappan, sensitizes cancer cells to apoptosis. Glioblastoma multiforme (GBM), which accounts for most cases of central nervous system malignancy, has a very poor prognosis and lacks effective therapeutic interventions. We, therefore, investigated the effects of different concentrations of and different periods of exposure to brazilin on cell proliferation and apoptosis in the glioma U87 cell line. Cell proliferation was investigated by MTT assays and growth curve analysis, apoptosis was assessed by FACS analysis and western blot studies. Brazilin showed dose-dependent inhibition of cell proliferation and induction of apoptosis in glioma cells. It also increased the ratio of cleaved poly-(ADP)-ribose polymerase and decreased the expression of caspase-3 and caspase-7.

Anti-inflammatory lignans from the fruits of Acanthopanax sessiliflorus.

A new lignan, named acanthosessilin A (1), as well as eight known lignan and lignan glycosides 2-9 were isolated from an ethanolic extract of Acanthopanax sessiliflorus fruits. The chemical structures were determined by spectroscopic methods, including HR-EIMS, 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.

Effects of Natural Bioactive Products on the Growth and Ginsenoside Contents of Panax ginseng Cultured in an Aeroponic System.

This study was conducted to evaluate the effects of natural bioactive products such as Manda enzyme (T1), Yangmyeongwon (T2), effective microorganisms (T3), and Kelpak (T4) on the growth and ginsenoside contents of Panax ginseng cultured in an aeroponic system using a two-layer vertical type of nutrient bath under natural light conditions. The growth of ginseng plants showed specific characteristics according to the positions in which they were cultured due to the difference of light transmittance and temperature in the upper and lower layers during aeroponic culture in a two-layer vertical type of system. The growth of the aerial part of the leaves and stems of ginseng plants cultured in the lower layer (4,000 to 6,000 lx, 23℃ to 26℃) of the nutrient bath was observed to be superior to that of the ginseng plants cultured in the upper layer (12,000 to 15,000 lx, 25℃ to 28℃). The leaf area was significantly larger in the treatment of T2 and T4 (46.70 cm(2)) than with other treatments. Conversely, the values of the root weight and root diameter were higher in ginseng plants cultured in the upper layer of the nutrient bath. The root weight was significantly heavier in the treatment of T4 (6.46 g) and T3 (6.26 g) than with other treatments. The total ginsenoside content in the leaves and roots was highest in the ginseng plants cultured by the treatment of T1, at 16.20%, while the total ginsenoside content obtained by other treatments decreased in the order of T4, T5 (control), T2, and T3, at 13.21%, 12.30%, 14.84%, and 14.86%, respectively. The total ginsenoside content of the ginseng leaves was found to be significantly higher in the treatment of T1 in the lower layer of the nutrient bath, at 15.30%, while the content of the ginseng roots in the treatments of T3 and T4, at 1.27% and 1.23%, respectively, was significantly higher than in other treatments in the upper layer of the nutrient bath.

Xenophilus aerolatus sp. nov., isolated from air.

A novel aerobic, Gram-negative, motile, rod-shaped bacterial strain designated 5516S-2(T) was isolated from an air sample taken in Suwon, Republic of Korea. Colonies were yellow-pigmented and circular with entire margins. 16S rRNA gene sequence analysis showed that strain 5516S-2(T) was closely related to Xylophilus ampelinus DSM 7250(T) (97.6 % sequence similarity), Variovorax soli KACC 11579(T) (97.5 %) and Xenophilus azovorans DSM 13620(T) (97.1 %). However, the phylogenetic tree indicated that strain 5516S-2(T) formed a separate clade from Xenophilus azovorans. Strain 5516S-2(T) displayed 42, 31 and 30 % DNA-DNA relatedness to the type strains of Xenophilus azovorans, Xylophilus ampelinus and V. soli, respectively. The major fatty acids (>10 % of total fatty acids) were C(16 : 0) (33.3 %), C(17 : 0) cyclo (18.8 %), C(18 : 1)omega7c (17.5 %) and summed feature 3 (comprising C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH; 13.0 %). The DNA G+C content was 69 mol%. The major quinone was ubiquinone Q-8. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and two unknown aminophospholipids. Genotypic and phenotypic characteristics clearly distinguished strain 5516S-2(T) from closely related species and indicated that it represents a novel species within the genus Xenophilus, for which the name Xenophilus aerolatus sp. nov. is proposed. The type strain is 5516S-2(T) (=KACC 12602(T)=DSM 19424(T)).

Roseomonas aerilata sp. nov., isolated from an air sample.

A polyphasic study was carried out to clarify the taxonomic position of a pink-coloured, Gram-negative bacterium isolated from air in the Suwon region of Korea. The novel strain, 5420S-30(T), grew in the temperature range of 5-35 degrees C (optimum 30 degrees C) and pH range of 5-9 (optimum pH 6-7). Growth did not occur in the presence of as little as 1 % (w/v) NaCl. It contained Q-10 as the predominant ubiquinone. The major fatty acids were C(18 : 1)omega7c, summed feature 3 (C(16 : 1)omega7c/iso-C(15 : 0) 2-OH) and C(16 : 0) (together representing 77.7 % of the total). The DNA G+C content was 72.1 mol%. The 16S rRNA gene sequence similarities between strain 5420S-30(T) and members of the genus Roseomonas were in the range 91.6-95.1 %, with the highest sequence similarities (95.1 and 94.5 %, respectively) to Roseomonas aquatica TR53(T) and Roseomonas gilardii ATCC 49956(T). On the basis of its phenotypic and genotypic characteristics, strain 5420S-30(T) represents a novel species of the genus Roseomonas, for which the name Roseomonas aerilata sp. nov. is proposed, with 5420S-30(T) (=KACC 12521(T) =DSM 19363(T)) as the type strain.

Rudanella lutea gen. nov., sp. nov., isolated from an air sample in Korea.

An orange-coloured bacterial strain, designated 5715S-11(T), was isolated from an air sample in Suwon, Republic of Korea. The strain was strictly aerobic, Gram-negative, non-spore-forming, non-flagellated and rod-shaped, frequently forming filaments. Growth of the strain was observed at 4-40 degrees C (optimum, 30 degrees C), pH 6.0-8.0 (optimum, pH 7.0) and 0-2 % (w/v) NaCl. Phylogenetically, strain 5715S-11(T) was shown to be a member of the family Spirosomaceae within the phylum Bacteroidetes. Its closest relatives were Spirosoma linguale LMG 10896(T) (87.9 % 16S rRNA gene sequence similarity) and Larkinella insperata LMG 22510(T) (86.2 % 16S rRNA gene sequence similarity). Predominant cellular fatty acids were summed feature 3 (C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH), C(16 : 1)omega5c and iso-C(15 : 0). Major polar lipids were phosphatidylethanolamine and unknown aminolipids and polar lipids. On the basis of the evidence from this polyphasic study, strain 5715S-11(T) is considered to represent a novel species of a new genus, for which the name Rudanella lutea gen. nov., sp. nov. is proposed. The type strain of Rudanella lutea is 5715S-11(T) (=KACC 12603(T) =DSM 19387(T)).

Knoellia aerolata sp. nov., isolated from an air sample in Korea.

An aerobic, Gram-positive, non-motile, non-spore-forming, rod-coccus-shaped bacterium, strain 5317S-21(T), was isolated from an air sample from Suwon city, Republic of Korea. The isolate was able to grow within a pH range of 5.0-9.0 and a temperature range of 5-35 degrees C and it tolerated up to 2 % (w/v) NaCl. The cell-wall peptidoglycan contained meso-diaminopimelic acid as diagnostic diamino acid. The predominant isoprenoid quinone was MK-8(H(4)). The major polar lipids were phosphatidylinositol, phosphatidylethanolamine and diphosphatidylglycerol; phosphatidylglycerol and several unknown phospholipids were also detected. Mycolic acids were absent. The only whole-cell sugar was glucose. The major cellular fatty acids were iso-C(16 : 0), C(17 : 1)omega8c and iso-C(15 : 0). 16S rRNA gene sequence analysis indicated that strain 5317S-21(T) was related phylogenetically to members of the genus Knoellia, with 97.4 % sequence similarity to the type strains of Knoellia sinensis and Knoellia subterranea. The G+C content of the genomic DNA of strain 5317S-21(T) was 73 mol%. Levels of DNA-DNA relatedness between strain 5317S-21(T) and the type strains of Knoellia sinensis and Knoellia subterranea were 37 and 41 %, respectively. It was concluded that strain 5317S-21(T) represents a novel species of the genus Knoellia, for which the name Knoellia aerolata sp. nov. is proposed. The type strain is 5317S-21(T) (=KACC 20583(T) =DSM 18566(T)).

Ureibacillus composti sp. nov. and Ureibacillus thermophilus sp. nov., isolated from livestock-manure composts.

Two Gram-negative, rod-shaped, thermophilic bacterial strains, HC145(T) and HC148(T), were isolated from a compost sample from a compost facility in Ichon, Korea. Sequencing of the 16S rRNA genes of HC145(T) and HC148(T) and comparative analyses of the resulting sequences clearly showed that these strains had a phylogenetic affiliation to the genus Ureibacillus. The level of 16S rRNA similarity between the two novel strains was 98.4 % and the levels of sequence similarity between them and existing Ureibacillus species were 97.8-98.1 (HC145(T)) and 97.4-98.7 % (HC148(T)). The DNA-DNA reassociation values between the two strains and the type strains of Ureibacillus species ranged from 38 to 51 %. The polar lipid profiles for both isolates consisted of phosphatidylglycerol, diphosphatidylglycerol, phospholipids and glycolipids of unknown composition. The major quinones were MK-8, MK-9 and MK-7, the peptidoglycan type was l-Lys<--d-Asp and the main cellular fatty acid was iso-C(16 : 0). The DNA G+C contents of strains HC145(T) and HC148(T) were 42.4 and 38.5 mol%, respectively. On the basis of the data from this polyphasic study, strains HC145(T) and HC148(T) represent members of the genus Ureibacillus, for which the names Ureibacillus composti sp. nov. and Ureibacillus thermophilus sp. nov., respectively, are proposed. The type strain of U. composti is HC145(T) (=KACC 11361(T) =DSM 17951(T)) and the type strain of U. thermophilus is HC148(T) (=KACC 11362(T) =DSM 17952(T)).

Epidemiological study of clonorchiasis and metagonimiasis along the Geum-gang (River) in Okcheon-gun (county), Korea.

The endemic status of clonorchiasis and metagonimiasis along the Geum-gang (River) in Okcheon-gun (County) in Korea was examined. From February to December 2000, stools of total 1,081 inhabitants living in 5 villages were examined. Each stool specimen was examined by both the cellophane thick smear method and the formalin-ether sedimentation technique. Egg-positive cases were further analyzed by Stoll's egg-counting technique, and praziquantel was administered to positive cases. The egg-positive rates for Clonorchis sinensis and Metagonimus species were 9.3% and 5.5%, respectively, and the double infection rate was 3.5%. The numbers of eggs per gram (EPG) of feces of C. sinensis and Metagonimus sp. were 918 +/- 1,463 and 711 +/- 947, respectively. The egg-positive rates for C. sinensis and Metagonimus sp. in the riverside area were 14.2% and 8.4%, respectively, which were significantly higher than those of the inland area (3.2% and 1.7%, respectively). The egg-positive rates of C. sinensis and Metagonimus sp. in males (16.7% and 10.0%) were significantly higher than those of females (3.5% and 1.8%). However, there were no significant differences of EPG values between localities and sexes. The prevalence of clonorchiasis and metagonimiasis in this survey was significantly lower than that in the previous reports. However, there is still a high prevalence of infection with C. sinensis and Metagonimus sp. in this region, especially in the riverside area.