The understanding of lithium (Li) nucleation and growth is important to design better electrodes for high-performance batteries. However, the study of Li nucleation process is still limited because ...of the lack of imaging tools that can provide information of the entire dynamic process. We developed and used an operando reflection interference microscope (RIM) that enables real-time imaging and tracking the Li nucleation dynamics at a single nanoparticle level. This dynamic and operando imaging platform provides us with critical capabilities to continuously monitor and study the Li nucleation process. We find that the formation of initial Li nuclei is not at the exact same time point, and Li nucleation process shows the properties of both progressive and instantaneous nucleation. In addition, the RIM allows us to track the individual Li nucleus's growth and extract spatially resolved overpotential map. The nonuniform overpotential map indicates that the localized electrochemical environments substantially influence the Li nucleation.
Anti-CRISPR proteins (Acrs) targeting CRISPR-Cas9 systems represent natural “off switches” for Cas9-based applications. Recently, AcrIIC1, AcrIIC2, and AcrIIC3 proteins were found to inhibit ...Neisseria meningitidis Cas9 (NmeCas9) activity in bacterial and human cells. Here we report biochemical and structural data that suggest molecular mechanisms of AcrIIC2- and AcrIIC3-mediated Cas9 inhibition. AcrIIC2 dimer interacts with the bridge helix of Cas9, interferes with RNA binding, and prevents DNA loading into Cas9. AcrIIC3 blocks the DNA loading step through binding to a non-conserved surface of the HNH domain of Cas9. AcrIIC3 also forms additional interactions with the REC lobe of Cas9 and induces the dimerization of the AcrIIC3-Cas9 complex. While AcrIIC2 targets Cas9 orthologs from different subtypes, albeit with different efficiency, AcrIIC3 specifically inhibits NmeCas9. Structure-guided changes in NmeCas9 orthologs convert them into anti-CRISPR-sensitive proteins. Our studies provide insights into anti-CRISPR-mediated suppression mechanisms and guidelines for designing regulatory tools in Cas9-based applications.
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•Crystal structures of Cas9-bound AcrIICs suggest distinct inhibitory mechanisms•AcrIIC2 interferes with RNA- and DNA-loading steps through binding to Cas9 BH motif•AcrIIC3 induces Cas9 dimerization by interacting with the HNH domain and REC lobe•Cas9 enzymes can be reengineered to become susceptible to AcrIIC’s inhibition
Zhu et al. report biochemical and structural data that suggest molecular mechanisms of AcrIIC2- and AcrIIC3-mediated inhibition of Cas9. The two inhibitors employ distinct means to block Cas9 activity that include binding to different regions, targeting distinct steps of catalysis, and inhibiting different scopes of Cas9 orthologs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Novel theranostics based on photosensitizer‐conjugated carbon dots is reported. The prepared C‐dots–Ce6 has good stability and high water dispersibility and solubility, non‐cytotoxicity, good ...biocompatibility, enhanced photosensitizer fluorescence detection and remarkable photodynamic efficacy upon irradiation. The C‐dots–Ce6 conjugate is a good candidate with excellent imaging and tumor‐homing ability for NIR fluorescence imaging monitored PDT treatment.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A weaker solvent was constantly added at the middle of the two columns to set up a two-step solvent gradient in twin-column recycling chromatography so that the eluotropic strength of the downstream ...liquid was reduced. Therefore, the back edge of the band moved faster than the front edge during the circulation of the solute band, initiating special gradient compression to effectively counteract the band spreading. Herein, modified recycling chromatography was applied to the simultaneous purification and concentration of minor impurities in the bulk drug. Taking orlistat as an example, the target impurity with only 0.7% content in orlistat bulk drug was isolated, giving a purity of 96%. Its concentration was enhanced by 9.4 times. Investigations on operating conditions verified that decreasing the eluent eluotropic strength, increasing the solvent gradient, extending the column switching interval, and enhancing the number of switches within proper ranges were beneficial to the improvement of separation.
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IJS, KILJ, NUK, PNG, UL, UM
7-Xylosyl-10-deacetyl paclitaxel is a crucial semisynthetic precursor of paclitaxel, which could prevent cancer cells from dividing and growing. In this study, twin-column recycling chromatography ...with a step solvent gradient was applied to the isolation and purification of 7-xylosyl-10-deacetyl paclitaxel. By introduction of a weak solvent between the two columns, band broadening was counteracted to facilitate the separation process. Also the effects of various variables including the magnitude of solvent gradient, feeding volume, switch number, and interval were comprehensively investigated, and the operating conditions were systematically optimized. In the results, 7-xylosyl-10-deacetyl paclitaxel was successfully refined from 23.90% to almost 100%, with a remarkable yield of over 95%. This study demonstrates the distinct advantage of utilizing a new chromatography system in the separation of natural products.
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IJS, KILJ, NUK, PNG, UL, UM
Background
Several immune‐mediated diseases have been shown to be associated with an increased risk of cardiovascular disease. However, studies evaluating the association between inflammatory bowel ...disease and risk of cardiovascular disease reported inconsistent results. We assessed the association between inflammatory bowel disease and risk of ischemic heart disease in a meta‐analysis of cohort studies.
Methods and Results
We conducted a literature search of PubMed and Embase up to October 2016 to identify relevant studies. The summary relative risks were calculated using the random‐effects models. To explore the source of heterogeneity, we performed subgroup and sensitivity analysis. We included 10 cohort studies that satisfied our inclusion criteria. Patients with inflammatory bowel disease were associated with an increased risk of ischemic heart disease (relative risk: 1.244; 95% CI, 1.142–1.355). Considerable heterogeneity was observed. Crohn's disease showed a significantly increased risk of ischemic heart disease (relative risk=1.243; 95% CI, 1.042–1.482) and a positive association was also observed in ulcerative colitis (relative risk=1.206; 95% CI, 1.170–1.242).
Conclusions
Based on meta‐analysis of cohort studies, we found an increased risk of ischemic heart disease in patients with inflammatory bowel disease. Large long‐term prospective studies are warranted to confirm our results.
Direct ethanol fuel cells (DEFCs) provide a portable and environmentally friendly power source with high energy density. However, the slow kinetic of the ethanol oxidation reaction (EOR) has hindered ...the commercialization of DEFCs. Palladium (Pd)-based nanomaterials are the best promising catalysts for EOR due to the high catalytic activities and relatively abundant reserves. In this paper, we developed a simple and green way for the preparation of palladium hydride (PdH0.43) and Au/PdH0.43 heterostructures. Ethylene glycol (EG) provided the source of H atoms for the formation of PdH0.43 in synthesis process. The as-synthesized PdH0.43 and Au/PdH0.43 nanocrystals were extremely stable under ambient conditions and annealing at 300 °C under Ar. Compared with PdH0.43 and commercial Pd/C, Au/PdH0.43 presented a higher mass activity of 2659 mA mg−1, a lower oxidation peak potential, and a higher catalytic stability for oxidizing ethanol. Remarkably, the improved catalytic performance might arise from the synergistically modulation of electronic structure, the enhanced resistance to poisoning products and the acceleration of electron transfer by the formation of palladium hydrides and abundant heterostructures of Au/PdH0.43. This work provides a promising reference for the development of metal-hydride nanomaterials and heterostructures as efficient catalysts.
•The PdH0.43 and Au/PdH0.43 were prepared with ethylene glycol as the H source.•The PdH0.43 and Au/PdH0.43 were extremely stable in the air over six months.•Au/PdH0.43 can maintain the stability of structure even annealing at 300 °C in Ar.•Au/PdH0.43 exhibited a higher performance toward EOR than PdH0.43 and Pd/C.•The improved activities might arise from the doping of H and heterostructures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•We invented a technology of an easy-prepared and low-cost chip consisting of 3D silver microspheres (AgMSs).•The aggregation of micron-sized silver particles can induce much more hotspots of ...enhanced Raman scattering.•We proposed that Raman enhancement mechanism of 3D silver microspheres lay in the 3D synergetic effects.•We demonstrated the trace detection of pesticide residue in Chinses tea.
Due to the excessive use of fungicides, pesticide residues have become a growing concern in recent years. Herein, we demonstrated an easy-prepared and low-cost surface enhanced Raman Scattering (SERS) chip composed of 3D silver microspheres (AgMSs) pattern for the quantitative testing of carbendazim in Chinese tea. Compared with the common monolayer SERS substrate, the 3D patterns formed by self-assembly AgMSs with fine nanostructure can offer much more aggregation-induced hotspots and generate strong 3D synergetic effects. Furthermore, when the thickness of the 3D pattern exceeded 6 μm, we replaced the conductive supporting coatings using the glass slides to reduce the cost without any impact on SERS properties. The prepared 3D chips achieved the determination of carbendazim within the linear range of 0.1–10 mg/L and the detection limit of 0.01 mg/L. It is simple and sensitive enough for the detection of most pesticide residues or other harmful organic molecules in our food or environment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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