Consequently, SWCNTs have an adverse effect on protoplasts and leaves through oxidative stress, leading to a certain amount of programmed cell death. Although nanomaterials have great advantages in many respects, the benefits and side effects still need to be assessed carefully.

Two-dimensional (2D) materials have attracted tremendous interest as fluorescence quenchers of dye-labeled biomolecules for application in biosensing. Metal-organic framework (MOF) nanosheets, as a new type of 2D material, have rarely been studied as bioanalytical platforms. Herein, we synthesize a series of ultrathin lanthanide-based MOF (MOF-Ln) nanosheets as a dye-labeled aptamer platform. The fluorescence quenching or recovery on the MOF-Ln nanosheets is determined by the charge properties (positive or negative) of the labeled fluorophores. The negatively charged fluorophores experience a fluorescence 'turn-down followed by turn-down' process, whereas the positively charged fluorophores experience a fluorescence 'turn-down followed by turn-up' process. The interesting fluorescence quenching properties of the MOF-Ln nanosheets make them an excellent two-color sensing platform for the intracellular detection of biomolecules. NPG Asia Materials (2017) 9, e354; doi:10.1038/am.2017.7; published online 10 March 2017 INTRODUCTION Two-dimensional (2D) nanomaterials have been attracting extensive research interest due to their unique physical and chemical properties, as well as their potential scientific and technological applications in the fields of gas storage, sensing, electronics, energy conversion and storage, and electrocatalysis. 1 In the area of biomedical applications, 2D nanosheets with an extremely high surface area, such as graphene and its derivative graphene oxide, have been successfully used for biomedical imaging, drug delivery and cancer therapy. 2,3 Other emerging nanosheets (for example, MoS 2 , WS 2 and MnO 2 ) with a good fluorescence-quenching ability also exhibit selective adsorption affinity toward single-stranded DNA (ssDNA) versus double-stranded DNA (dsDNA). [4][5][6][7] These results have inspired studies to exploit the potential biological applications of novel 2D nanosheets. Very recently, 2D metal-organic framework (MOF) thin films or nanosheets have been successfully synthesized and exfoliated by several groups. [8][9][10] Their potential biological applications remain to be explored.MOFs are a fascinating class of functional materials that have been extensively studied for applications in gas storage, 11 catalysis, 12 separation 13 and sensing. 14 MOFs are certainly very promising for fabricating multifunctional luminescent sensors, because both the metal and the ligand units can provide platforms for generating luminescence and some guest molecules loaded on the MOFs can also emit or induce luminescence. 14 A variety of MOFs have been already

The only discovery of Earth Trojan 2010 TK7 and the subsequent launch of OSIRIS-REx motive us to investigate the stability around the triangular Lagrange points L4 and L5 of the Earth. In this paper we present detailed dynamical maps on the (a0, i0) plane with the spectral number (SN) indicating the stability. Two main stability regions, separated by a chaotic region arising from the ν3 and ν4 secular resonances, are found at low (i0 ≤ 15 • ) and moderate (24 • ≤ i0 ≤ 37 • ) inclinations respectively. The most stable orbits reside below i0 = 10 • and they can survive the age of the Solar System. The nodal secular resonance ν13 could vary the inclinations from 0 • to ∼ 10 • according to their initial values while ν14 could pump up the inclinations to ∼ 20 • and upwards. The fine structures in the dynamical maps are related to higher-degree secular resonances, of which different types dominate different areas. The dynamical behaviour of the tadpole and horseshoe orbits, reflected in their secular precession, show great differences in the frequency space. The secular resonances involving the tadpole orbits are more sensitive to the frequency drift of the inner planets, thus the instabilities could sweep across the phase space, leading to the clearance of tadpole orbits. We are more likely to find terrestrial companions on horseshoe orbits. The Yarkovsky effect could destabilize Earth Trojans in varying degrees. We numerically obtain the formula describing the stabilities affected by the Yarkovsky effect and find the asymmetry between the prograde and retrograde rotating Earth Trojans. The existence of small primordial Earth Trojans that avoid being detected but survive the Yarkovsky effect for 4.5 Gyr is substantially ruled out.

Soluble dietary fibers (SDF) are fermented more than insoluble dietary fibers (IDF), but their effect on colonic bacterial community structure and function remains unclear. Thus, bacterial community composition and function in the colon of BALB/c mice (n = 7) fed with a high level (approximately 20%) of typical SDF, oat-derived β-glucan (G), microcrystalline cellulose (M) as IDF, or their mixture (GM), were compared. Mice in group G showed a lowest average feed intake (p < 0.05) but no change on the average body weight gain (p > 0.05) compared to other groups, which may be associated with the highest concentration of colonic propionate (p < 0.05) in these mice. The bacterial α-diversity of group G was significantly lower than other groups (p < 0.01). In group G, the relative abundance of bacteria belonging to the phylum Bacteroidetes was significantly increased, whereas bacteria from the phylum Firmicutes were significantly decreased (p < 0.01). The core bacteria for different treatments showed distinct differences. Bacteroides, Dehalobacterium, and Prevotella, including known acetogens and carbohydrate fermenting organisms, were significantly increased in relative abundance in group G. In contrast, Adlercreutzia, Odoribacter, and Coprococcus were significantly more abundant in group M, whereas Oscillospira, Desulfovibrio, and Ruminoccaceae, typical hydrogenotrophs equipped with multiple carbohydrate active enzymes, were remarkably enriched in group GM (p < 0.05). The relative abundance of bacteria from the three classes of Proteobacteria, Betaproteobacteria, Gammaproteobacteria (including Enterobacteriaceae) and Deltaproteobacteria, were significantly more abundant in group G, indicating a higher ratio of conditional pathogenic bacteria in mice fed dietary β-glucan in current study. The predicted colonic microbial function showed an enrichment of “Energy metabolism” and “Carbohydrate metabolism” pathways in mice from group G and M, suggesting that the altered bacterial community in the colon of mice with the two dietary fibers probably resulted in a more efficient degradation of dietary polysaccharides. Our result suggests that the influence of dietary β-glucan (SDF) on colonic bacterial community of mice was more extensively than MCC (IDF). Co-supplementation of the two fibers may help to increase the bacterial diversity and reduce the conditional pathogens in the colon of mice.

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