There has been a long-standing debate about the mechanism of the unusual superconductivity in alkali-intercalated fullerides. In this Letter, using high-resolution angle-resolved photoemission ...spectroscopy, we systematically investigate the electronic structures of superconducting K_{3}C_{60} thin films. We observe a dispersive energy band crossing the Fermi level with the occupied bandwidth of about 130 meV. The measured band structure shows prominent quasiparticle kinks and a replica band involving the Jahn-Teller active phonon modes, which reflects strong electron-phonon coupling in the system. The electron-phonon coupling constant is estimated to be about 1.2, which dominates the quasiparticle mass renormalization. Moreover, we observe an isotropic nodeless superconducting gap beyond the mean-field estimation (2Δ/k_{B}T_{c}≈5). Both the large electron-phonon coupling constant and large reduced superconducting gap suggest a strong-coupling superconductivity in K_{3}C_{60}, while the electronic correlation effect is suggested by the observation of a waterfall-like band dispersion and the small bandwidth compared with the effective Coulomb interaction. Our results not only directly visualize the crucial band structure but also provide important insights into the mechanism of the unusual superconductivity of fulleride compounds.
Abstract
Bladder cancer (BLCA) is one of the most frequent genitourinary cancers, with a high rate of morbidity and mortality. The connection of m6A-related lncRNAs with PD-L1 and tumor immune ...microenvironment (TIME) in BLCA prognosis was extensively investigated in this study, which could suggest novel therapeutic targets for further investigation. 30 m6A-associated lncRNAs with predictive values from the TCGA data set were identified with co-expression analysis. Cluster2 was correlated with a poor prognosis, upregulated PD-L1 expression, and higher immune ratings. Cluster2 had larger amounts of resting CD4 memory-activated T cells, M2 macrophages, neutrophils, and NK cells infiltration. “CHEMOKINE SIGNALING PATHWAY” was the most significantly enriched signaling pathway according to GSEA, which may play an important role in the different immune cell infiltrates between cluster1/2. The risk model for m6A-related lncRNAs could be employed in a prognostic model to predict BLCA prognosis, regardless of other clinical features. Collectively, m6A-related lncRNAs were linked to PD-L1 and TIME, which would dynamically affect the number of tumor-infiltrating immune cells. m6A-related lncRNAs may be key mediators of PD-L1 expression and immune cells infiltration and may strongly affect the TIME of BLCA.
We introduce the antibody landscape, a method for the quantitative analysis of antibodymediated immunity to antigenically variable pathogens, achieved by accounting for antigenic variation among ...pathogen strains. We generated antibody landscapes to study immune profiles covering 43 years of influenza A/H3N2 virus evolution for 69 individuals monitored for infection over 6 years and for 225 individuals pre- and postvaccination. Upon infection and vaccination, titers increased broadly, including previously encountered viruses far beyond the extent of cross-reactivity observed after a primary infection. We explored implications for vaccination and found that the use of an antigenically advanced virus had the dual benefit of inducing antibodies against both advanced and previous antigenic clusters. These results indicate that preemptive vaccine updates may improve influenza vaccine efficacy in previously exposed individuals.
To characterise the genetics of splenic marginal zone lymphoma (SMZL), we performed whole exome sequencing of 16 cases and identified novel recurrent inactivating mutations in Kruppel-like factor 2 ...(KLF2), a gene whose deficiency was previously shown to cause splenic marginal zone hyperplasia in mice. KLF2 mutation was found in 40 (42%) of 96 SMZLs, but rarely in other B-cell lymphomas. The majority of KLF2 mutations were frameshift indels or nonsense changes, with missense mutations clustered in the C-terminal zinc finger domains. Functional assays showed that these mutations inactivated the ability of KLF2 to suppress NF-κB activation by TLR, BCR, BAFFR and TNFR signalling. Further extensive investigations revealed common and distinct genetic changes between SMZL with and without KLF2 mutation. IGHV1-2 rearrangement and 7q deletion were primarily seen in SMZL with KLF2 mutation, while MYD88 and TP53 mutations were nearly exclusively found in those without KLF2 mutation. NOTCH2, TRAF3, TNFAIP3 and CARD11 mutations were observed in SMZL both with and without KLF2 mutation. Taken together, KLF2 mutation is the most common genetic change in SMZL and identifies a subset with a distinct genotype characterised by multi-genetic changes. These different genetic changes may deregulate various signalling pathways and generate cooperative oncogenic properties, thereby contributing to lymphomagenesis.
Subambient daytime radiative cooling (SDRC) provides a promising electricity‐ and cryogen‐free pathway for global energy‐efficiency. However, current SDRC systems require stringent surface designs, ...which are neither cost‐effective nor eco‐friendly, to selectively emit thermal radiation to outer space and simultaneously maximize solar reflectance. Here, a generic method is developed to upgrade the conventional building‐coating materials with a peculiar self‐adaptive SDRC effect through combining particle scattering, sunlight‐excited fluorescence, and mid‐infrared broadband radiation. It is also theoretically proved that heat exchange with the sky can eliminate the use of resonant microstructures and noble metal mirrors in conventional SDRC, and also leads to enhanced daytime cooling yet suppressed nighttime overcooling. When exposed to direct sunlight, the upgraded coating over an aluminum plate can achieve 6 °C (7 °C on a scale‐model building) below the ambient temperature under a solar intensity of 744 W m−2 (850 W m−2), yielding a cooling power of 84.2 W m−2. The results pave the way for practical large‐scale applications of high‐performance SDRC for human thermal comfort in buildings.
A waterborne building coating with smart subambient radiative cooling (SSRC) is created based on a new design concept, which combines particle scattering, sunlight‐excited fluorescence, and mid‐infrared broadband radiation. Consequently, conventional building‐coating materials can be engineered at low cost to realize SSRC, facilitating an eco‐friendly solution for widespread applications of the SSRC technology in buildings for improved human comfort.
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The effect of the chemical component and microstructure, not to mention their facile modification, of the coating/wrapping carbon layer on the electrochemical performance of the Si/C ...composite anode in lithium ion batteries (LIBs) hasn’t been actively explored although Si/C has been recognized as one of the most promising route for the high energy density LIBs. Herein we propose a novel nitrogen-plasma doping route to modify the top carbon film in an elaborately constructed layered Si/C composite anode. The electrochemical performance, e.g., the initial coulombic efficiency (CE), cycle stability and specific capacity of the composite anode is drastically improved by this plasma processing due to the increased kinetics of lithium ions. By means of the appropriate adjustment of the N doping ratio and N chemical configuration in the carbon layer through a N2/H2 plasma processing, the lithium diffusion rate in the composite anode was memorably increased as the pseudocapacitance effects promoted. The optimized Si/C composite exhibits a high capacity of 1120.7 mA h g−1 and an initial CE of 80.8% at the current of 2 A g−1 after a long cycle of 1500, increasing by ~40% of specific capacity and ~29% of the initial CE.
Aims
This study examined the biotransformation pathway of ginsenoside Rb1 by the fungus Esteya vermicola CNU 120806.
Methods and Results
Ginsenosides Rb1 and Rd were extracted from the root of Panax ...ginseng. Liquid fermentation and purified enzyme hydrolysis were employed to investigate the biotransformation of ginsenoside Rb1. The metabolites were identified and confirmed using NMR analysis as gypenoside XVII and gypenoside LXXV. A mole yield of 95·4% gypenoside LXXV was obtained by enzymatic conversion (pH 5·0, temperature 50°C). Ginsenoside Rd was used to verify the transformation pathway under the same reaction condition. The product Compound K (mole yield 49·6%) proved a consecutive hydrolyses occurred at the C‐3 position of ginsenoside Rb1.
Conclusions
Strain CNU 120806 showed a high degree of specific β‐glucosidase activity to convert ginsenosides Rb1 and Rd to gypenoside LXXV and Compound K, respectively. The maximal activity of the purified glucosidase for ginsenosides transformation occurred at 50°C and pH 5·0. Compared with its activity against pNPG (100%), the β‐glucosidase exhibited quite lower level of activity against other aryl‐glycosides. Enzymatic hydrolysate, gypenoside LXXV and Compound K were produced by consecutive hydrolyses of the terminal and inner glucopyranosyl moieties at the C‐3 carbon of ginsenoside Rb1 and Rd, giving the pathway: ginsenoside Rb1→ gypenoside XVII → gypenoside LXXV; ginsenoside Rd→F2→Compound K, but did not hydrolyse the 20‐C, β‐(1‐6)‐glucoside of ginsenoside Rb1 and Rd.
Significance and Impact of the Study
The results showed an important practical application on the preparation of gypenoside LXXV. Additionally, this study for the first time provided a high efficient preparation method for gypenoside LXXV without further conversion, which also gives rise to a potential commercial enzyme application.
Herein we propose a novel plasma-based route to synergistically modulate the microstructures of the current collectors of nickel foam and subsequently the Si/C composite active coatings, restraining ...the huge volume expansion of silicon anode materials during lithiation/delithiation in Lithium ion batteries. The nickel foam surface is tailored to form the temperature-dependent nanostructures by the Ar/H2-plasma. And a 3D Si/C nano-composite structure is constructed in combination of silicon via magnetron sputtering and carbon through the inductively coupled plasma vapor deposition (ICP-CVD). The plasma-activated nickel foam surface leads to the crystallization of the sputtered silicon, and the significantly increased surface area results in the increases of loading rate of Si/C composites (e.g., 75% @room temperature). The electrochemical performance, e.g., the specific capacity, cycle stability and the initial Coulombic efficiency of the composite anode is drastically improved by the plasma processing. The cauliflower-like Si/C composites on the Ar/H2-plasma modified nickel foam at 300 °C exhibits a high capacity of 1941.2 mA h g−1 at 0.1 A g−1 after 100 cycles, and 976 mA h g−1 at 1.6 A g−1 after 500 cycles, increasing by 3–7 times in terms of the current density when compared with the case without the plasma processing.
•Abundant nanostructure of nickel foam tailored by Ar/H2 plasma.•The plasma-activated nickel foam surface leads to the crystallization of the sputtered silicon.•The significantly increased surface area of nickel foam results in the increases of loading rate (e.g., 45% @300 °C).•The plasma modified nickel foam drastically boosted the electrochemical performance of the 3D Si/C nano-composite anode.
► High speed machining of Ti-6Al-4V is achieved. ► The segment spacing of serrated chip increases as the shear band evolves. ► The shear band evolution model was proposed to predict segment spacing. ...► The new model considers the shear band evolution and the material convection. ► Good prediction of segment spacing was achieved over a wide range of cutting speed.
Cutting experiments were performed on Ti-6Al-4V alloy over a wide range of cutting speeds. The transition of chip morphology from continuous to serrated is observed with increasing the cutting speeds, which is found to be ascribed to a periodic shear band formation that caused by thermo-plastic instability occurred within the primary shear zone (PSZ). Further microscopic observations reveal that the spacing of these periodic shear bands, i.e., the segment spacing, is significantly related to the evolution degree of shear band which increases with increasing the cutting speed. Since the segment spacing is the most important parameter to characterize the chip serration, to predict the segment spacing is fundamentally useful for the understating of serrated chip formation mechanism. However, the complicated conditions of high speed machining (HSM) give rise to greater difficulties for the prediction of segment spacing, and there is still no theoretical prediction has yet considered the effect of shear band evolution. In this work, by analyzing the plastic deformation within the PSZ, and taking into account the evolution of shear band as well as the material convection caused by chip flow, a new theoretical model is developed to predict the segment spacing, in which the momentum diffusion due to unloading within the shear band had been considered. The predictions of this model were compared with the experimental and simulated results, which clearly reveal that the proposed model can satisfactorily capture the process of chip segmentation over a wide range of cutting speeds.
An experimental device, based on the light-gas gun technology, was set up to realize high speed cutting over a wide range of cutting speeds from 30m/s to 200m/s. High-speed cutting experiments were ...performed on AISI 1045 steels. The investigation of chip morphology, micro-structures, micro-hardness and the finished surface integrity were carried out, focusing on the physical phenomena accompanying the saw-tooth chip formation. The results reveal that, with increasing the cutting speed, the transition of chip morphology from continue to saw-tooth could be attributed to repeated thermoplastic shear-banding rather than periodic cracking. In particular, a severe material flow leading to mass transfer of heat was observed at very high cutting speed. The effect of mass transfer of heat on thermoplastic shear instability was further investigated, which implies that the mass transfer of heat would retard the formation of saw-tooth chip. Finally, the influence of cutting speed and mass transfer on the temperature distribution during high speed machining was briefly discussed.
► We developed an experimental device to provide high speed machining. ► The cause of saw-tooth chip formation for AISI 1045 steel is investigated. ► Mass transfer of heat due to chip flow retards the saw-tooth chip formation. ► Increasing cutting speed weakens thermal diffusion and enhances mass transfer.
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