The plasmon coupling between a Au nanorod and a small Au nanosphere has been studied with scattering measurements, electrodynamic simulations, and model analysis. The spatial perturbation of the ...nanosphere leads to distinct spectral changes of the heterodimer. The plasmonic responses, including Fano resonance, are remarkably sensitive to the nanosphere position on the nanorod, the gap distance, and the nanocrystal dimensions. The nanosphere dipole is intriguingly found to rotate around the nanorod dipole to achieve favorable attractive interaction for the bonding dipole–dipole mode. The sensitive spectral response of the heterodimer to the spatial perturbation of the nanosphere offers an approach to designing plasmon rulers of two spatial coordinates for sensing and high-resolution measurements of distance changes.
Elongated plasmonic nanoparticles have been extensively explored over the past two decades. However, in comparison with the dipolar plasmon mode that has attracted the most interest, much less ...attention has been paid to multipolar plasmon modes because they are usually thought to be "dark modes", which are unable to interact with far-field light efficiently. Herein, we report on an intriguing far-field scattering phenomenon, colour routing, based on longitudinal multipolar plasmon modes supported by high-aspect-ratio single Ag nanorods. Taking advantage of the distinct far-field behaviours of the odd and even multipolar plasmon modes, we demonstrate two types of colour routing, where the incident white light can be scattered into several beams with different colours as well as different propagation directions. Because of the narrow linewidths of the longitudinal multipolar plasmon modes, there is little spectral overlap between the adjacent peaks, giving rise to outstanding colour selectivity. Our experimental results and theoretical model provide a simple yet effective picture for understanding the far-field behaviour of the longitudinal multipolar plasmon modes and the resultant colour routing phenomenon. Moreover, the outstanding colour routing capability of the high-aspect-ratio Ag nanorods enables nanoscale optical components with simple geometries for controlling the propagation of light below the diffraction limit of light.
To explore carbide superconductors with higher transition temperature, two novel carbon structures of cage‐network are designed and their superconductivity is studied by doping metals. MC6 and MC10 ...are respectively identified as C24 and C32 cage‐network structures. This study finds that both carbon structures drive strong electron–phonon interaction and can exhibit superconductivity above liquid nitrogen temperature. Importantly, the superconducting transition temperatures above 100 K are predicted to be achieved in C24‐cage‐network systems doped by Na, Mg, Al, In, and Tl at ambient pressure, which is far higher than those in graphite, fullerene, and other carbides. Meanwhile, the superconductivity of cage‐network carbides is also found to be sensitive to the electronegativity and concentration of dopant M. The result indicates that the higher transition temperatures can be obtained by optimizing the carbon‐cage‐network structures and the doping conditions. The study suggests that the carbon‐cage‐network structure is a direction to explore high‐temperature superconducting carbides.
The novel carbon structures of cage‐network is designed. The superconducting transition temperature above 100 K are predicted to be achieved in C24‐cage‐network systems doped by metals at ambient pressure, which is far higher than those in graphite, fullerene, and other carbides. The study suggests that the carbon‐cage‐network structure is a direction to explore high‐temperature superconducting carbides.
Ovarian cancer is the third most common cancer in the female reproductive organs and epithelial ovarian cancer has the highest lethality of all gynecological cancers. Pomegranate fruit juice (PFJ) ...has been shown to inhibit the growth of several types of cancer other than ovarian cancer. In this study, we exposed the ovarian cancer cell line A2780 to PFJ and two of its components (ellagic acid and luteolin). MTT and wound healing assays demonstrated that all three treatments suppressed the proliferation and migration of the ovarian cancer cells. In addition, western blotting and ELISA assays showed that the expression levels of MMP2 and MMP9 gradually decreased after treatment with increasing concentrations of ellagic acid and luteolin. To confirm our findings in the in vitro experiments, we used another ovarian cancer cell line, ES-2, in nude mice experiments. All three treatments inhibited tumor growth without obvious side-effects. Furthermore, compared with the control group, the expression levels of MMP2 and MMP9 were depressed. Ellagic acid induced a greater effect than luteolin, suggesting that ellagic acid might be a promising candidate for further preclinical testing for treatment of human ovarian cancer.
Copper-catalyzed asymmetric dearomative azidation of tryptamines using azidobenziodoxolone as an azidating reagent was developed, which affords a variety of 3a-azido-pyrroloindolines in good to high ...enantioselectivities under mild reaction conditions. The azides could be readily transformed into the corresponding 3a-amino-pyrroloindolines
via
reduction and 1,2,3-triazole derivatives
via
a click reaction.
A facile strategy for the construction of enantioenriched 3a-azido-pyrroloindolines
via
a copper-catalyzed asymmetric dearomative azidation of tryptamines is presented.
Further increasing the critical temperature and/or decreasing the stabilized pressure are the general hopes for the hydride superconductors. Inspired by the low stabilized pressure associated with Ce ...4f electrons in superconducting cerium superhydride and the high critical temperature in yttrium superhydride, we carry out seven independent runs to synthesize yttrium-cerium alloy hydrides. The synthetic process is examined by the Raman scattering and X-ray diffraction measurements. The superconductivity is obtained from the observed zero-resistance state with the detected onset critical temperatures in the range of 97-141 K. The upper critical field towards 0 K at pressure of 124 GPa is determined to be between 56 and 78 T by extrapolation of the results of the electrical transport measurements at applied magnetic fields. The analysis of the structural data and theoretical calculations suggest that the phase of Y
Ce
H
in hexagonal structure with the space group of P6
/mmc is stable in the studied pressure range. These results indicate that alloying superhydrides indeed can maintain relatively high critical temperature at relatively modest pressures accessible by laboratory conditions.
Computational materials science has grown in China in recent times. Hai-Qing Lin gives an overview of Chinas eorts towards a Materials Genome Initiative and the challenges faced. Due to the rapid ...development of computational physics and quantum chemistry as research disciplines since 1990, and enabling advances in computer technology and soware, computational-based materials research is growing in importance. One of the most challenging issues in materials scienceis to identify materials with potentially good properties, out of thousands of candidates. The traditional approach, based on trial-and-error experiments, is time-consuming, resource-intensive and oen fails to discover those materialswith optimum properties. In addition, understanding the mechanisms behind how atomic and microscopic structures control macroscopic properties would signicantly enhance search efficiency, aiding the prediction of complex materials properties for advanced applications. Computational approaches towards materials science can oer substantial advances in this regard, providing shortcuts to new materials, and understanding of material behaviour. Given the substantial research and technological eorts towards materials science in China, it is no surprise that computational materials is a rapidly growing eld inChina.
Background
Limited studies have focused on the associated clinicopathologic features and short‐term prognostic impacts of metastatic patterns at initial diagnosis in differentiated thyroid cancer ...(DTC).
Methods
Overall, 530 individuals with distant DTC diagnosed between 2010 and 2014 were identified from Surveillance, Epidemiology, and End Results (SEER) database. Multinomial logistic regression model was used to assess the clinicopathologic factors influencing the pattern of distant metastasis. Kaplan–Meier method and multivariable Cox regression were used to estimate the short‐term effects of metastatic patterns on overall (OS) and thyroid cancer‐specific survival (TCSS).
Results
Fifty, 111, 263, 59 and 47 patients presented with distant lymph node (LN)‐only, bone‐only, lung‐only, bone plus lung, and liver and/or brain metastases (Mets), respectively. Regional lymph node metastasis (LNM) and follicular histotype were the only confirmed risk factors for distant LN‐only Mets and bone‐only Mets, respectively. Larger tumour size, extrathyroidal extension (ETE) and papillary histotype were associated with lung‐only Mets. Synchronous bone and lung Mets were more likely to occur in older patients. In addition, patients with distant LN‐only Mets had hardly any negative effect on OS and TCSS, whereas those with synchronous bone and lung or liver/brain Mets predicted unfavourable short‐term outcomes, regardless of whether they received total thyroidectomy and radioisotopes.
Conclusions
Different clinicopathologic factors predispose to different patterns of metastases with profound short‐term survival differences among DTC patients. Our findings may help to determine effective pretreatment screening for aggressive metastatic patterns at initial diagnosis, and thus to provide additional treatment or access of clinical trials for these patients.
The plasmon coupling between metal nanocrystals can lead to large plasmon shifts, enormous electric field enhancements, and new plasmon modes. Metal nanorods, unlike spherical ones, possess a ...transverse and a longitudinal plasmon mode owing to their geometrical anisotropy. Consequently, the plasmon coupling between metal nanorods is much more complicated than that between nanospheres. For the latter, experimental approaches, simple scaling relationships, and exact analytic solutions have been developed for describing the plasmon coupling. In this study, we have carried out extensive finite-difference time-domain simulations to understand the plasmon coupling in the dimers of Au nanorods that are aligned along their length axes. The effects of the gap distance, longitudinal plasmon energy, and end shape of the nanorod monomers on the plasmon coupling have been scrutinized. The coupling energy diagrams show a general anticrossing behavior. All of them can be rescaled into one simple and universal hyperbolic formula. A theoretical model based on two interacting mechanical oscillators has been developed to understand the plasmon coupling between two arbitrarily varying Au nanorods. This model, together with the universal equation, allows for the determination of the coupled plasmon energies of Au nanorod dimers with high accuracies. Furthermore, the Fano interference has been observed in the nanorod heterodimers, with its behavior being dependent on the gap distance and plasmon energies of the nanorod monomers. Our results will be useful for predicting the coupled plasmon energies of metal nanorod dimers in a variety of plasmonic applications and understanding the Fano resonance in plasmonic nanostructures.
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