Switching effective oxygen reduction and evolution performance by controlled graphitization of a cobalt-nitrogen-carbon framework system

We report a purposely designed route for the synthesis of a promising carbon-based electrocatalyst for both ORR (oxygen reduction reaction) and OER (oxygen evolution reaction) from zeolitic imidazolate frameworks (ZIFs). Firstly, precursor ZIFs are rationally designed with a blend of volatile zinc to induce porosity and stable cobalt to induce graphitic domains. Secondly, the self-modulated cobalt–nitrogen–carbon system (SCNCS) is shown to be an effective ORR catalyst after graphitization at mild temperatures. Finally, the best OER catalyst is developed by enhancing graphitization of the SCNCS. For the first time, solely by switching the graphitization conditions of SCNCS, excellent ORR or OER performance is realized. This approach not only opens up a simple protocol for simultaneous optimization of nitrogen doping and graphitization at controlled cobalt concentrations, but also provide a facile method of developing such active catalysts without the use of extensive synthesis procedures

How do acupuncture practitioners use pattern identification – An international web-based survey?

© 2019 Elsevier GmbH Introduction: Training and practice of Traditional East Asian Medicine (TEAM) varies globally although similar diagnostic methods are used based on patients presenting signs and symptoms. These methods assist in determining disease patterns and treatment principles. The use of diagnostic principles and pattern identification (PI) was explored in this survey of TEAM practice across different countries. Methods: A web-based survey was disseminated to acupuncture professional membership organisations in UK, Australia, Italy, Korea and China using a Survey Monkey link between December 2015 and September 2017. Results: The 618 fully completed responses were available for comparison (UK 66, Australia 106, China 87, Italy 226, Korea 133). Demographic characteristics varied; UK practitioners were more likely to be female (71%) compared to the other countries (51-59%), Koreans tended to be under 40yrs (80%), compared to elsewhere (14-27%). Korean, UK and Australian respondents had fewer practitioners with biomedical training, 95% of the Italians had a biomedical qualification. TEAM diagnostic methods were more likely practised in the UK and Australian samples ( > 90%) but were lowest for the Italian sample (78%). TCM differential diagnosis was the predominant type of PI. PI was rated essential by 85% of Chinese practitioners, versus 32% Koreans, 45% Italians, 67% UK and 68% Australian respondents. Conclusion: This first international survey about acupuncturists use of PI demonstrated wide variation. The sample was limited to certain countries and relied on dissemination by specific professional bodies and participants completing an electronic questionnaire which may have affected responses but provides a platform for future studies

Co3+-O-V4+ cluster in CoVOx nanorods for efficient and stable electrochemical oxygen evolution

The development of cost-efficient and long-term stable catalysts for the oxygen evolution reaction (OER) is crucial to produce clean and sustainable H2 fuels from water. Here we demonstrate a cobalt vanadium oxide (CoVOx-300) working as such an efficient and durable electrocatalyst. Such an active catalyst is beneficial from the balanced Co3+-O-V4+ active species, which show the high surface Co3+ contents with matched V4+ generated by rapid heat treatment. The CoVOx-300 with highest Co3+/Co2+ ratio of 1.4 and corresponding highest V4+/ V5+ ratio of 1.7 exhibits remarkable OER activity with an overpotential of 330 mV at current density of 10 mA cm−2 (η10), a shallow Tafel slope of only 46 mV dec-1 and a current density of 100 mA cm−2 at an overpotential of 0.38 V vs RHE, which is 20 times higher than the active CoOx-300 and 1000 times higher than VOx-300. The catalyst also shows excellent stability for 10 h in alkaline media and a 40 % reduced activation energy to the counterpart, CoOx-300. The overpotential (η10) of CoVOx-300 also shows nearly 70 and 80 mV lower than the corresponding CoOx-300 and CoVOx catalysts, respectively and 20 % lower Tafel slope than the commercial benchmark catalyst RuO2. Thus, this study for the first time demonstrates that surface Co3+-O-V4+ species play a crucial role in improving electrocatalytic properties and stability for water oxidation reaction and the approaches allow the rational design and synthesis of other active transition metal oxides toward efficient OER activity

Strong correlations and orbital texture in single-layer 1T-TaSe2

Strong electron correlation can induce Mott insulating behaviour and produce intriguing states of matter such as unconventional superconductivity and quantum spin liquids. Recent advances in van der Waals material synthesis enable the exploration of Mott systems in the two-dimensional limit. Here we report characterization of the local electronic properties of single- and few-layer 1T-TaSe2 via spatial- and momentum-resolved spectroscopy involving scanning tunnelling microscopy and angle-resolved photoemission. Our results indicate that electron correlation induces a robust Mott insulator state in single-layer 1T-TaSe2 that is accompanied by unusual orbital texture. Interlayer coupling weakens the insulating phase, as shown by reduction of the energy gap and quenching of the correlation-driven orbital texture in bilayer and trilayer 1T-TaSe2. This establishes single-layer 1T-TaSe2 as a useful platform for investigating strong correlation physics in two dimensions

Phylogeographic analysis and genetic structure of an endemic sino-japanese disjunctive genus Diabelia (caprifoliaceae)

The Sino-Japanese Floristic Region (SJFR) is a key area for plant phylogeographical research, due to its very high species diversity and disjunct distributions of a large number of species and genera. At present, the root cause and temporal origin of the discontinuous distribution of many plants in the Sino-Japanese flora are still unclear. Diabelia (Caprifoliaceae; Linnaeoideae) is a genus endemic to Asia, mostly in Japan, but two recent discoveries in China raised questions over the role of the East China Sea (ECS) in these species' disjunctions. Chloroplast DNA sequence data were generated from 402 population samples for two regions (rpl32-trnL, and trnH-psbA) and 11 nuclear microsatellite loci were screened for 549 individuals. Haplotype, population-level structure, combined analyses of ecological niche modeling, and reconstruction of ancestral state in phylogenies were also performed. During the Last Glacial Maximum (LGM) period after the Tertiary, Diabelia was potentially widely distributed in southeastern China, the continental shelf of the East China Sea and Japan (excluding Hokkaido). After LGM, all populations in China have disappeared except those in Zhejiang which may represent a Glacial refuge. Populations of Diabelia in Japan have not experienced significant bottleneck effects, and populations have maintained a relatively stable state. The observed discontinuous distribution of Diabelia species between China and Japan are interpreted as the result of relatively ancient divergence. The phylogenetic tree of chloroplast fragments shows the characteristics of multi-origin evolution (except for D. sanguinea). STRUCTURE analysis of nuclear Simple Sequence Repeat (nSSR) showed that the plants of the Diabelia were divided into five gene pools: D. serrata, D. spathulata, D. sanguinea, D. ionostachya (D. spathulata var. spathulata-Korea), and populations of D. ionostachya var. ionostachya in Yamagata prefecture, northern Japan. Molecular evidence provides new insights of Diabelia into biogeography, a potential glacial refuge, and population-level genetic structure within species. In the process of species differentiation, ECS acts as a corridor for two-way migration of animals and plants between China and Japan during glacial maxima, providing the possibility of secondary contact for discontinuously distributed species between China and Japan, or as a filter (creating isolation) during glacial minima. The influence of the ECS in speciation and biogeography of Diabelia in the Tertiary remains unresolved in this study. Understanding origins, evolutionary histories, and speciation will provide a framework for the conservation and cultivation of Diabelia

Bis(diisopropylammonium) dimethyldioxalatostannate

The six-coordinate Sn atom in bis(diisopropylammonium) dimethyldioxalatostannate, [(C3H7)(2)NH2](2)(+) [(CH3)(2)Sn(O2CCO2)](2-), exists in a cis-C2SnO4 coordination sphere [Sn-C 2.127 (5) Angstrom; C-Sn-C 109.2 (3)degrees]. The anion lies on a special position of 2 symmetry. The ammonium cations and the stannate anions are linked by hydrogen bonds into a linear chain

Bis(diisopropylammonium) diphenyldioxalatostannate(IV)

The six-coordinate Sn atom in bis(diisopropylammonium) diphenyldioxalatostannate(IV), [(C3H7)(2)NH2](2)(+) [(C6H5)(2)Sn(O2CCO2)](2-), exists in a cis-C2SnO4 octahedral coordination sphere [Sn-C 2.139 (7) and 2.144 (7) Angstrom; C-Sn-C 103.8 (3)degrees]. The ammonium cations and the stannate anions are linked by hydrogen bonds into a zigzag chain, running along the c axis of the monoclinic cell