A Stable and Conductive Covalent Organic Framework with Isolated Active Sites for Highly Selective Electroreduction of Carbon Dioxide to Acetate.

Electroreduction of CO2 to acetate provides a promising strategy to reduce CO2 emissions and store renewable energy, but acetate is usually a by-product. Here, we show a stable and conductive two-dimensional phthalocyanine-based covalent-organic framework (COF) as an electrocatalyst for reduction of CO2 to acetate with a single-product Faradaic efficiency (FE) of 90.3(2)% at -0.8 V (vs. RHE) and a current density of 12.5 mA cm-2 in 0.1 M KHCO3 solution. No obvious degradation was observed over 80 hours of continuous operation. Combined with the comparison of the properties of other catalysts with isolated metal active sites, theoretical calculations and in situ infrared spectroscopy revealed that the isolated copper-phthalocyanine active site with high electron density is conducive to the key step of C-C coupling of *CH3 with CO2 to produce acetate, and can avoid the coupling of *CO with *CO or *CHO to produce ethylene and ethanol.

Single-Product Faradaic Efficiency for Electrocatalytic of CO2 to CO at Current Density Larger than 1.2†A cm-2 in Neutral Aqueous Solution by a Single-Atom Nanozyme.

Electroreduction of CO2 to CO is a promising approach for the cycling use of CO2 , while it still suffers from impractical current density and durability. Here we report a single-atom nanozyme (Ni-N5 -C) that achieves industrial-scale performance for CO2 -to-CO conversion with a Faradaic efficiency (FE) exceeded 97 % over -0.8--2.4 V vs. RHE. The current density at -2.4 V vs. RHE reached a maximum of 1.23 A cm-2 (turnover frequency of 69.7 s-1 ) with an FE of 99.6 %. No obvious degradation was observed over 100 hours of continuous operation. Compared with the planar Ni-N4 site, the square-pyramidal Ni-N5 site has an increase and a decrease in the d z 2 ${{{\rm d}}_{{z}^{2}}}$ and dxz/yz orbital energy levels, respectively, as revealed by density functional theory calculations. Thus, the Ni-N5 catalytic site is more superior to activate CO2 molecule and reduce the energy barriers as well as promote the CO desorption, thus boosting the kinetic activation process and catalytic activity.

Highly Selective CO2 Electroreduction to C2H4 Using a Metal-Organic Framework with Dual Active Sites.

Conversion from CO2 to C2H4 is important for the development of energy and the environment, but the high energy barrier of hydrogenation of the *CO intermediate and C-C coupling step tend to result in C1 compounds as the main product and thus restrict the generation of C2H4. Here, we report a metal-organic framework (denoted as PcCu-Cu-O), composed of 2,3,9,10,16,17,23,24-octahydroxyphthalo-cyaninato)copper(II) (PcCu-(OH)8) ligands and the square-planar CuO4 nodes, as the electrocatalyst for CO2 to C2H4. Compared with the discrete molecular copper-phthalocyanine (Faradaic efficiency (FE) of C2H4 = 25%), PcCu-Cu-O exhibits much higher performance for electrocatalytic reduction of CO2 to C2H4 with a FE of 50(1)% and a current density of 7.3 mA cm-2 at the potential of -1.2 V vs RHE in 0.1 M KHCO3 solution, representing the best performance reported to date. In-situ infrared spectroscopy and control experiments suggested that the enhanced electrochemical performance may be ascribed to the synergistic effect between the CuPc unit and the CuO4 unit, namely the CO on the CO-producing site (CuO4 site) can efficiently migrate and dimerize with the *CO intermediate adsorbed on the C2H4-producing site (CuPc), giving a lower C-C dimerization energy barrier.

An effective snakebite first aid training method for medics in the Chinese troops: a RCT.

BACKGROUND: Snakebites can lead to lifelong consequences and is one of the main causes of death among military troops worldwide. However, few Chinese military medics know the proper first aid procedures for snakebites. Therefore, this study aimed to explore the impact of the Standard Operation Procedure (SOP) and checklist on Chinese military medics' ability to manage snakebite first aid. METHODS: This study was a prospective single-blind randomized controlled trial conducted in a military medical university of China from May to June 2017. A questionnaire-based survey was performed to collect the participants' socio-demographic profiles before the baseline measurement. During the baseline measurement, participants were requested to provide corresponding first aid that was responsive to the simulative situation portrayed by the SPs (standardized patients) and the evaluators then scored their performances according to a checklist for snakebite first aid scoring table. After the baseline measurement, they were randomly assigned to one of three intervention groups after stratification according to their baseline performance scores: group A received a self-learning course with textbooks (n = 27), group B received a self-learning training on the SOP and checklist (n = 27) and group C was engaged in an interactive discussion panel regarding the SOP and checklist (n = 26). After the interventions, participants received outcome measurements about snakebite first aid key points capability from the same evaluator and SP for each group to avoid observational error. The reviewers were blinded about the grouping in the trial. RESULTS: The baseline measurement yielded no significant difference (H = 1.647, P = 0.439) among the three groups. The post-intervention scores were higher than the pre-intervention scores for all three (A, B and C) groups (P = 0.008, P < 0.001 and P < 0.001, respectively). There was significant difference of the post-intervention scores among the three groups (F = 8.841, P < 0.001). Both post-intervention scores of group B and group C were higher than that of group A (P < 0.001 and P = 0.001, respectively), but no difference was found between group B and C (P = 0.695). The acceptance questionnaire score of SOP and checklist was mostly very satisfied, as the final scores of group B and group C were 4.62 ± 0.61 and 4.82 ± 0.45, respectively. CONCLUSIONS: In this study, the implementation of an SOP and checklist for snakebite first aid was shown to update and improve first aid treatment concepts in military medics. These intervention methods played an important role in improving the medics' cognition and understanding of snakebite first aid. Therefore, this finding suggests that SOP and checklist training should be further implemented in Chinese troops for snakebite care.

[Establishment and application of ELISAs based on rLipL32/1-LipL21-OmpL1/2 fusion antigen of Leptospira interrogans].

OBJECTIVE: To establish ELISAs based on rLipL32/1-LipL21-OmpL1/2 fusion antigen of Leptospira interrogans for detecting specific IgG and IgM in serum of patients with leptospirosis. METHODS: Microscope agglutination test(MAT) was performed to detect serum specimens from leptospirosis patients and to determine titers of rabbbit antiserum agaist rLipL32/1-LipL21-OmpL1/2 to reference standard strains of L. interrogans. By using rLipL32/1-LipL21-OmpL1/2, rLipL32/1, rLipL21 and rOmpL1/2 as the coated antigens, ELISAs for detecting specific serum IgM and IgG were established. The established ELISAs were applied to MAT-positive serum specimens from 107 patients with leptospirosis. RESULT: The results of MAT confirmed that 66% (71/107) of the patients were infected with L.interrogans serogroup Icterohaemorrhagiae, and the rLipL32/1-LipL21-OmpL1/2 antiserum were able to agglutinate all 15 reference standard L.interrogans strains with 1 : 20approximate, equals1 : 160 titers. The positive rates of ELISAs using rLipL32/1-LipL21-OmpL1/2, rLipL32/1, rLipL21 or rOmpL1/2 as the antigen were 89.7%, 75.7%, 85.1% and 79.4% for detecting IgM, respectively, while 99.1%, 99.1%, 94.4% and 86.0% for detecting IgG, respectively. The positive detection rate of rLipL32/1-LipL21-OmpL1/2-IgM-ELISA was higher than those of the other three IgM detection ELISAs (P<0.05). The positive detection rate of rLipL32/1-LipL21-OmpL1/2-IgG-ELISA was higher than that of rOmpL1/2-IgG-ELISA (P<0.05), while there was no significant differnce with that of rLipL21-IgG-ELISA and rLipL32/1-IgG-ELISA (P>0.05). CONCLUSION: The ELISAs using rLipL32/1-LipL21-OmpL1/2 as the antigen can be applied as a sensitive,specific and universal serological method for diagnosis of leptospirosis.rLipL32/1-LipL21-OmpL1/2-IgM-ELISA shows a definite value for early diagnosis of leptospirosis compared with the other ELISAs used in this study.

[Prokaryotic expression of trigeminy artificial fusion gene of Leptospira interrogans and the immunogenicity of its products].

OBJECTIVE: To construct lipL32/1-lipL21-OmpL1/2 fusion gene of Leptospira interrogans and its prokaryotic expression system, and to identify the immunogenicity of its products. METHODS: PCR using linking primers was applied to construct lipL32/1-lipL21-OmpL1/2 fusion gene and a prokaryotic expression system of the fusion gene was then established using routine genetic engineering technique. SDS-PAGE was used to examine output of the target recombinant protein rLipL32/1-LipL21-OmpL1/2. Double immunodiffusion and Western Blot assay were applied to identify immunogenicity of rLipL32/1-LipL21-OmpL1/2. RESULT: lipL32/1-lipL21-OmpL1/2 fusion gene with correct sequence and its prokaryotic expression system E.coli BL21DE3pET42a-lipL32/1-lipL21-ompL1/2 was obtained in this study. The output of rLipL32/1-LipL21- OmpL1/2 after optimisation was 37.78 mg/L. The immunodiffusion titer of rabbit antiserum against rLipL32/1-LipL21-OmpL1/2 was 1:4. The rLipL32/1-LipL21-OmpL1/2 antiserum was able to recognize rLipL32/1-LipL21-OmpL1/2, rLipL32/1, rLipL21 and rOmpL1/2. Positive Western hybridization signals were found among rLipL32/1-LipL21-OmpL1/2 and rabbit antiserum against whole cell of strain 56601 and serum from patients infected with L.interrogans serogroups Icterohaemorrhagiae, Grippotyphosa, Autumnalis and Pomona. CONCLUSION: The fusion gene lipL32/1-lipL21-OmpL1/2 and its prokaryotic expression system were successfully constructed in this study. The expressed fusion protein can be used as the antigen for developing universal genetic engineering vaccine and universal serological tests of leptospirosis.

A systematic study of the genus Atlanticus Scudder, 1894 from Zhejiang, China (Orthoptera: Tettigoniidae: Tettigoniinae).

Six species of genus Atlanticus have been recorded from Zhejiang, China prior to this study. We describe 2 new species, A. fallax sp. nov. and A. interval. sp. nov. Their morphology, songs, COI genes and distributions are compared. The type specimens are deposited in East China Normal University, Biology of History Museum (ECNU).

Efficient production of a thermophilic 2-deoxyribose-5-phosphate aldolase in glucose-limited fed-batch cultivations of Escherichia coli by continuous lactose induction strategy.

The production of a thermophilic 2-deoxyribose-5-phosphate aldolases (DERA) in Escherichia coli BL21 under continuous lactose induction strategy was investigated. The process was combined with the exponential feeding method, controlling the feeding rate to maintain the specific growth rate at 0.15 h(-1). The results indicate that the lactose concentration in the feed medium affected directly the expression of the target protein. The use of 50 g/L in the feed medium resulted in the biomass concentration of 39.3 g DCW/L, and an expression level of above 30%, and the maximum final DERA concentration of 16,200 U/L. Furthermore, the acetate concentration remained at a low level in the fed-batch phase, less than 0.5 g/L. In conclusion, combining glucose feeding with lactose induction is a more powerful way to achieve high cell density cultures and to efficiently produce the thermophilic DERA. The results also indicate the potential industrial utility in the scale production of other recombinant proteins.