A high-resolution miniature spectrometer has been demonstrated by utilizing a 128-channel integrated filter array, fabricated by using the combinatorial deposition technique, as a dispersive component whose passbands range from 722.0 to 880.0 nm with a bandwidth (or spectral resolution) from 1.7 to 3.8 nm and an average channel interval of 1.2 nm. The miniature spectrometer is smaller than 1 cm3 without any moving parts. This kind of miniature spectrometer has the advantages of very low payload, high resolution, and high reliability simultaneously, which are especially urgently needed for space applications.

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We report the first pyrrole-ring surface-functionalized graphene quantum dots (p-GQDs) prepared by a two-step hydrothermal approach under microwave irradiation in an ammonia medium. The most distinct feature of the functionalized GQDs is that both the excitation and emission wavelengths fall into the visible-light region. The p-GQDs are excited by visible light at λ(ex) 490 nm (2.53 eV) to emit excitation-independent photoluminescence at a maximum wavelength of λ(em) 550 nm. This is thus far the longest emission wavelength reported for GQDs. Stable photoluminescence is achieved at pH 4-10 with an ionic strength of 1.2 mol L(-1) KCl. These features make the p-GQDs excellent probes for bio-imaging and bio-labeling, which is demonstrated by imaging live HeLa cells.

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Anaerobic ammonium oxidation (anammox) widely occurs in marine ecosystems, and it plays an important role in the global nitrogen cycle. But in freshwater ecosystems its occurrence, distribution and contribution, especially in extreme environments, are still not well known. In this study, anammox process was investigated in some extreme environments of freshwater ecosystems, such as those with high (above 75°C) and low (below -35°C) temperature, high (pH > 8) and low (pH < 4) pH and eutrophy (the concentration of NH4 (+) -N > 300 mg kg(-1) ). The polymerase chain reaction (PCR) screening results showed that anammox bacteria were widespread in the examined sediments from freshwater extreme environments. Quantitative PCR showed that the abundance of anammox bacteria ranged from 6.94 × 10(4) to 8.05 × 10(6) hydrazine synthase (hzsB) gene copies g(-1) dry soil. (15) N-labelled incubation experiments indicated the occurrence of anammox in all examined sediments and the potential anammox rates ranged from 0.02 to 6.24 nmol N g(-1)  h(-1) , with a contribution of 3.45-58.74% of the total N2 production. In summary, these results demonstrate the occurrence of anammox in these extreme environments, inferring that anammox may harbour a wide ecological niche in the freshwater ecosystems.