From Quaternary Carbon to Tertiary C(sp3)-Si and C(sp3)-Ge Bonds: Decyanative Coupling of Malononitriles with Chlorosilanes and Chlorogermanes Enabled by Ni/Ti Dual Catalysis.

Transition-metal-catalyzed C-Si/Ge cross-coupling offers promising avenues for the synthesis of organosilanes/organogermanes, yet it is fraught with long-standing challenges. A Ni/Ti-catalyzed strategy is reported here, allowing the use of disubstituted malononitriles as tertiary C(sp3) coupling partners to couple with chlorosilanes and chlorogermanes, respectively. This method enables the catalytic cleavage of the C(sp3)-CN bond of the quaternary carbon followed by the formation of C(sp3)-Si/C(sp3)-Ge bonds from ubiquitously available starting materials. The efficiency and generality are showcased by a broad scope for both of the coupling partners, therefore holding the potential to synthesize structurally diverse quaternary organosilanes and organogermanes that were difficult to access previously.

Geometric and Electronic Engineering in Co/VN Nanoparticles to Boost Bifunctional Oxygen Electrocatalysis for Aqueous/Flexible Zn-Air Batteries.

Modulating metal-metal and metal-support interactions is one of the potent tools for augmenting catalytic performance. Herein, highly active Co/VN nanoparticles are well dispersed on three-dimensional porous carbon nanofoam (Co/VN@NC) with the assistance of dicyandiamide. Studies certify that the consequential disordered carbon substrate reinforces the confinement of electrons, while the coupling of diverse components optimizes charge redistribution among species. Besides, theoretical analyses confirm that the regulated electron configuration can significantly tune the binding strength between the active sites and intermediates, thus optimizing reaction energy barriers. Therefore, Co/VN@NC exhibits a competitive potential difference (ΔE, 0.65 V) between the half-wave potential of ORR and OER potential at 10 mA cm-2, outperforming Pt/C+RuO2 (0.67 V). Further, catalyst-based aqueous/flexible ZABs present superior performances with peak power densities of 156 and 85 mW cm-2, superior to Pt/C-based counterparts (128 and 73 mW cm-2). This research provides a pivotal foundation for the evolution of bifunctional catalysts in the energy sector.

Oxalic Acid-Assisted Vacancy Engineering Promotes Iron-Copper Sulfide Nanosheets for High-Current Density Water Oxidation.

The effective defect and interface coupling are pivotal for the promotion of the catalytic activity for the oxygen evolution reaction. Herein, we report novel hybrid nanosheets with sulfur vacancies composed of FeS2 and Cu39S28 grown on Cu foam (Vs-FeS2/Cu39S28). The optimal Vs-FeS2/Cu39S28 exhibits a high current output of 500 mA cm-2 at a low overpotential of 370 mV and robust stability for 60 h at 100 mA cm-2, surpassing the values of most previously reported Cu-based catalysts. Furthermore, a two-electrode electrolyzer made by pairing the prepared catalyst with commercial Pt/C requires a low cell voltage of 1.75 V at 100 mA cm-2 and is retained over 80 h. Key to its excellent performance is the synergism between intertwined FeS2 and Cu39S28 domains, enriched by the deliberate introduction of sulfur vacancies, thus optimizing the electronic structure and causing the proliferation of catalytic active sites. This work presents a potent Cu-based electrocatalyst and emphasizes the leveraging of non-precious metals for efficient water oxidation.

The occurrence of lower-than-expected bulk NCCN values over the marginal seas of China - Implications for competitive activation of marine aerosols.

In this study, we combined the measured bulk particle number concentration (NCN), particle number size distribution (PNSD) and bulk cloud condensation nuclei concentration (NCCN) at various supersaturation (SS) levels to investigate competitive activation of aerosols in the marine atmospheres over the marginal seas of China during two winter campaigns Campaign A (December 9-19, 2019) and Campaign B (December 28, 2019-January 16, 2020). During the two campaigns, we observed various categories of aerosols, i.e., long-range transport continental aerosols, clean marine aerosols, grown new particles ranging from nucleation mode to larger sizes, and grown pre-existing particles ranging from Aitken mode to accumulation mode size, etc. We found that the measured NCCN increased by only approximately 30 % with increases in SS levels from 0.2 % to 1.0 %, e.g., (1.8 ± 1.4) × 103 cm-3 at SS = 0.2 % and (2.4 ± 1.4) × 103 cm-3 at SS = 1.0 % during Campaign A. We further calculated the hygroscopicity parameter kappa (κ) by combining simultaneously measured PNSD and bulk NCCN to explore the causes. The calculated κ values were below 0.1 at SS = 0.4 % during the 72 % (or 88 %) period of Campaign A (or Campaign B). When κ values below 0.1 (or 0.2) were excluded, the remaining κ values were apparently reasonable, with an average of 0.22 (or 0.36) and a standard deviation of 0.10 (or 0.21) at SS = 0.4 % during Campaign A (or Campaign B). The unexpectedly lower κ values were discussed in terms of competitive activation of aerosols in marine atmospheres together with its net contribution to lowering the measured bulk NCCN below the expected value.

[Influences of human beta-defensin 1 on the replication and expression of HPV18 in Hela cell].

OBJECTIVE: Investigate the influences of human beta-defensinl (hbetaD1) on the replication and expression of HPV18 in Hela cell. METHODS: Gene transfection: mediated by Fugen HD, hbetaD1/psectag plasmid was transfected to Hela cell [hbetaD1/psectag : liposome complexes (hbetaD1/psectag : lip)group], and control groups [psectag : liposome complexes(psectag : lip) group and blank group) were also established. After transfection, the expression of the target gene in Hela cell was investigated by the method of immunocytochemistry. 48 h and 72 h after the transfection, the change of the copy number of HPV18 DNA in Hela cell was investigated respectively by the quantitative fluorescent PCR method, and the change of the HPV18 E6 mRNA in Hela cell was evaluated by the semiquantitative RT-PCR. RESULTS: 48 h and 72 h after the transfection of hbetaD1/psectag plasmid to Hela cell, hbetaD1 was expressed in both of the two groups, and the latter showed a tendency of stronger expression. Compared with the control groups, the copy number of HPV18 DNA in Hela cell in the hbetaD1/psectag : lip group increased at 48 h and decreased at 72 h after the transfection, but the change was not statistically significant. 48 h after the transfection, compared with the control groups, the expression of HPV18 E6 mRNA in Hela cell in the hbetaD1/psectag : lip group changed a little; and 72 h after the transfection, the expression level of HPV18 E6 mRNA decreased significantly (P < 0.05). CONCLUSION: hbetaD1 displayed an inhibitory effect to the expression of HPV18 mRNA in Hela cell in a concentration-dependent pattern, but no significant effect on the duplication of HPV18 DNA.