Salinity changes the nitrification activity and community composition of comammox Nitrospira in intertidal sediments of Yangtze River estuary.

The newly discovered complete ammonia-oxidizing (comammox) Nitrospira has been identified in different environments, including coastal environments, where salinity is one of the most important factors for the abundance and activity of nitrifiers. Here, we demonstrate the effect of salinity on comammox Nitrospira, canonical ammonia-oxidizing bacteria (AOB), and ammonia-oxidizing archaea (AOA) in the intertidal sediments of the Yangtze River estuary based on microcosm experiments, DNA stable-isotope probing (DNA-SIP), and potential ammonium-oxidation rate (PAR) tests for different groups of ammonia oxidizers with selective inhibitors. During microcosm incubations, the abundance of comammox Nitrospira was more sensitive to increased salinity than that of other ammonia oxidizers. The results obtained with DNA-SIP heavy fractions showed that the dominant phylotype in clade A.2 (containing genes involved in the adaptation to haloalkaline environments) had high proportions in comammox Nitrospira community under both freshwater (0.06% salinity) and highly saline water (3% salinity) conditions. In contrast, another phylotype of clade A.2 (which lacks these genes) was dominant only under freshwater conditions. The PARs confirmed that comammox Nitrospira presented greater contributions to nitrification under freshwater conditions with a PAR of 4.37 ± 0.53 mg N·day-1·kg soil-1 (54%) than under saline water conditions with a PAR of 0.60 ± 0.94 mg N·day-1·kg soil-1 (18%). Moreover, AOA were specific to saline water conditions, whereas AOB were common under both freshwater and saline water conditions (44% and 52%, respectively). The present study provided evidence that salinity markedly affects the activity of comammox Nitrospira, and that the salt sensitivity of different phylotypes varies. IMPORTANCE Complete ammonia oxidation (comammox) is a newly discovered type of nitrification through which ammonia is oxidized to nitrate in an organism. Comammox Nitrospira were abundantly found in coastal ecosystems and demonstrated high community diversity. Changes in salinity are considered one of the most important factors to comammox Nitrospira in coastal ecosystems; however, reports on the correlation between them remain inconsistent. Therefore, it is critical to experimentally determine the influence of salinity on comammox Nitrospira in the coastal ecosystem. This study demonstrated a clear effect of salinity on the abundance, activity, and relative contribution of different ammonia oxidizers, especially for comammox Nitrospira. To the best of our knowledge, this is the first study demonstrating comammox Nitrospira activity at seawater salinities, implying the existence of a salt-tolerant type comammox Nitrospira, despite its activity being much lower than in freshwater conditions. The indicated correlation between the activity of specific comammox Nitrospira and salinity is anticipated to provide insights into the distribution of comammox Nitrospira and their potential contributions in estuaries and coastal ecosystems.

Room-Temperature Phosphorescent Co-Crystal Showing Direct White Light and Photo-Electric Conversion.

The development of molecular crystalline materials with efficient room-temperature phosphorescence has been obtained much attention due to their fascinating photophysical properties and potential applications in the fields of data storage, bioimaging and photodynamic therapy. Herein, a new co-crystal complex [(DCPA) (AD)2] (DCPA = 9,10-di (4-carboxyphenyl)anthracene; AD = acridine) has been synthesized by a facile solvothermal process. Crystal structure analysis reveals that the co-crystal possesses orderly and alternant arrangement of DCPA donors and AD acceptors at molecular level. Fixed by strong hydrogen bonds, the DCPA molecule displays seriously twisty spatial conformation. Density functional theory (DFT) calculations show well separation of HOMO and LUMO for this co-crystal system, suggesting the efficient triplet excitons generation. Photoluminescence measurements show intensive cyan fluorescence (58.20 ns) and direct white phosphorescence (325 µs) emission at room-temperature. The transient current density-time curve reveals a typical switching electric response under the irradiation of simulated light, reveal that the [(DCPA) (AD)2] co-crystal has a high photoelectric response performance.

Efficient Energy-Transfer-Induced High Photoelectric Conversion in a Dye-Encapsulated Ionic Pyrene-Based Metal-Organic Framework.

The relationship between the aggregation states of pyrene-based linkers and the photoluminescence/photoelectric performance was well studied by the formation of an anionic metal-organic framework, [BMI]2[Mg3(TBAPy)2(H2O)4]·2dioxane, which shows highly enhanced light-harvesting and photoelectric conversion efficiency by the encapsulation of D-π-A cation dyes.

Angle-Dependent Polarized Emission and Photoelectron Performance of Dye-Encapsulated Metal-Organic Framework.

Molecule-based crystalline materials with angle-dependent polarized emission have attracted considerable attention owing to their extensive applications in displays and anticounterfeiting. Herein, one anionic metal-organic framework (MOF) {[Zn2.5(µ3-OH)(NDC)2(HNDC)](HPIM)}n was constructed on the basis of an excellent photoactive ligand naphthalene-1,4-dicarboxylic acid (H2NDC). The protonated 2-propylimidazole (HPIM) guests residing in the nanochannels of MOF can be exchanged by a D-π-A cationic dye. The resulted host-guest system shows a rare example of ratiometric fluorescent polarizations and highly enhanced photoelectron performance in comparison with the pristine MOF.

The complete genome of extracellular protease-producing Deinococcus sp. D7000 isolated from the hadal region of Mariana Trench Challenger Deep.

The general features and genomic characteristics of gram-positive Deinococcus sp. D7000 isolated from the hadal region of Mariana Trench Challenger Deep were analyzed in this study. Deinococcus sp. D7000 has a genome consisting of 4,558,742 bp, including one chromosome and nine plasmids. This strain exhibits extracellular protease activity under low temperatures. Among 4328 protein-coding sequences (CDSs), 47 encode serine peptidases. Multiple annotation analysis was used to identify two genes encoding extracellular subtilases. In addition, three types of extracellular secretion transporter systems were found upon pathway construction and analysis. Genome analysis offers insights into the putative pathway of extracellular protease and application prospect of Deinococcus sp. D7000 in enzyme development.

Long Afterglow of a Nonporous Coordination Polymer with Tunable Room-Temperature Phosphorescence by the Doping of Dye Molecules.

Metal-organic frameworks (MOFs) or coordination polymers (CPs)-based phosphorescence materials may provide a powerful route for photoelectric and optical recording devices. Herein, two phosphorescence ligands, iso-phthalic acid (IPA) and 2-methylimidazole (MIM), were selected to construct an nonporous CP {Zn(IPA)(MIM)2} (1) with a long-lived phosphorescence lifetime up to 552 ms. By the doping of Eosin Y (EY) dye molecules under an in situ process, the phosphorescence emission color of 1 can be expressly tuned from green to red. The light-harvesting range can also be vastly broadened from the UV to the visible region (550 nm). Photoelectron measurements reveal that the synergistic effect of bias voltage and illumination can greatly restrain electron-hole recombination for the generation of additional free charges.

Multiscale Structural Engineering of Ni-Doped CoO Nanosheets for Zinc-Air Batteries with High Power Density.

Zinc-air batteries offer a possible solution for large-scale energy storage due to their superhigh theoretical energy density, reliable safety, low cost, and long durability. However, their widespread application is hindered by low power density. Herein, a multiscale structural engineering of Ni-doped CoO nanosheets (NSs) for zinc-air batteries with superior high power density/energy density and durability is reported for the first time. In micro- and nanoscale, robust 2D architecture together with numerous nanopores inside the nanosheets provides an advantageous micro/nanostructured surface for O2 diffusion and a high electrocatalytic active surface area. In atomic scale, Ni doping significantly enhances the intrinsic oxygen reduction reaction activity per active site. As a result of controlled multiscale structure, the primary zinc-air battery with engineered Ni-doped CoO NSs electrode shows excellent performance with a record-high discharge peak power density of 377 mW cm-2 , and works stable for >400 h at 5 mA cm-2 . Rechargeable zinc-air battery based on Ni-doped CoO NSs affords an unprecedented small charge-discharge voltage of 0.63 V, outperforming state-of-the-art Pt/C catalyst-based device. Moreover, it is shown that Ni-doped CoO NSs assembled into all-solid-state coin cells can power 17 light-emitting diodes and charge an iPhone 7 mobile phone.

Formation of tungsten oxide nanowires by ion irradiation and vacuum annealing.

Here we reported the fabrication of tungsten oxide (WO3-x ) nanowires by Ar+ ion irradiation of WO3 thin films followed by annealing in vacuum. The nanowire length increases with increasing irradiation fluence and with decreasing ion energy. We propose that the stress-driven diffusion of the irradiation-induced W interstitial atoms is responsible for the formation of the nanowires. Comparing to the pristine film, the fabricated nanowire film shows a 106-fold enhancement in electrical conductivity, resulting from the high-density irradiation-induced vacancies on the oxygen sublattice. The nanostructure exhibits largely enhanced surface-enhanced Raman scattering effect due to the oxygen vacancy. Thus, ion irradiation provides a powerful approach for fabricating and tailoring the surface nanostructures of semiconductors.

[Impact of Maximum Precipitation in 2017 on the Runoff Component of Reclaimed Water-Intaking River].

The hydrology of rivers recharged with reclaimed water is an important factor controlling its aquatic environment and biochemical processes, which change during the wet season. To understand the impacts of precipitation on hydrological conditions, water samples were collected from seven sites in three periods (before the wet season and during and after the maximum precipitation in July 2017, with 3.3 return periods) throughout a reclaimed water intake area of the Chaobai River in the Shunyi District, Beijing. The hydrogen-oxygen isotope characteristics and chloride content were measured. The results show that the hydrogen and oxygen isotopes of precipitation are mainly affected by the amount of the effect. The minor variation in the later period is due to changes in the sources of moisture. Within three days after precipitation, the slope runoff continues and the fraction of each section varies greatly. The reclaimed water reaches the downstream section through the preferred pathway. The water component ratio of the slope runoff increases from 2% to 85.6% in the direction of the flow, while the reclaimed water ratio decreases from 90% to 67%. The stream remains effluent from sections SY01 to SY05 that are recharged by the slope runoff, reclaimed water, and in-site river water, while the sections SY06 to SY07 are mainly recharged by the slope runoff and in-site river water within three days after the precipitation (the stream effluent is unremarkable).

[Impact of Mainstream Backwater on the Water Environment of the Tributaries of the Three Gorges Reservoir at Low Water Level].

To prevent the eutrophication of tributaries and guarantee water quality and safety in the Three Gorges Reservoir, research on the impact of mainstream backwater on tributary water environments is of great significance. The investigation and sampling of the Yangtze mainstream and its major tributaries in the reservoir region were performed from August 7 to August 12, 2016, through which the overall hydrochemical environment of the Three Gorges Reservoir has been revealed, and the impact of mainstream backwater on the hydrochemical characteristics of main tributaries has been determined during the low water level operation period. The results showed the following:① The electrical conductivity of the mainstream varied from 291 µS·cm-1 to 336 µS·cm-1, whereas that of the mainstream backwater unaffected zone of the tributary varied from 183.7 µS·cm-1 to 518 µS·cm-1. The electrical conductivity of the mainstream backwater affected zone of the tributary varied from 267 µS·cm-1 to 330 µS·cm-1, which was close to the mainstream variation range. ② The variation range of the δD and δ18 O values of the mainstream were -81.60‰--75.16‰ and -11.57‰--0.26‰, whereas that of the mainstream backwater unaffected zone of tributaries were -59.94‰--43.67‰ and -9.00‰--6.04‰; those of the mainstream backwater affected zone of tributary were -77.85‰--50.75‰ and -11.06‰--7.33‰, which showed the same pattern as those of electrical conductivity and mass concentration of main anions and cations. This means that the mainstream affected the waterbody composition of tributaries through backwater as well as the chemical characterization of tributary water. The extent of mainstream backwater influence on tributaries was negatively correlated to the distance between the tributary estuary and Three Gorges Dam as well as tributary discharge. The hydrochemical characteristics of the mainstream backwater unaffected zone of the tributary were related to the tributary catchment properties. Tributaries with denser populations and higher proportions of cultivated land have poorer water quality. Mainstream backwater can pollute tributaries of better water quality and optimize those with poor water quality.

Effect of temperature on development and reproduction of Proprioseiopsis asetus (Acari: Phytoseiidae) fed on asparagus thrips, Thrips tabaci.

Thrips tabaci Lindeman (Thysanoptera: Thripidae) is one of the most important pests of asparagus in China. In this study the effects of five constant temperatures (15, 20, 25, 30 and 35 °C) on the growth, survivorship and reproduction of Proprioseiopsis asetus (Chant) (Acari: Phytoseiidae) fed on T. tabaci was examined under laboratory conditions. Development time of immatures decreased with increasing temperature. The lower egg-to-adult developmental threshold (T 0) and thermal constant (K) of P. asetus were estimated at 15.2 °C and 75.8 degree days by means of a linear model. Fertilized females fed on T. tabaci produced offspring of both sexes, whereas the offspring sex ratio [♀/(♀ + â™‚)] of P. asetus at 20-35 °C was female-biased (0.68-0.78) and not significantly influenced by temperature. Survivorship during immature development was significantly influenced by temperature, and was especially low at 15 °C. Pre- and post-oviposition periods of fertilized females shortened with the increase in temperature. The longest oviposition period was 20.4 days, at 25 °C, whereas at 15 °C the mites did not reproduce. Maximum average life time fecundity and mean daily fecundity was recorded at 25 and 35 °C, respectively; the intrinsic rate of increase ranged from 0.05 (20 °C) to 0.17 (35 °C). The results indicate the capability of P. asetus to develop and reproduce at a broad range of temperatures, especially above 25 °C, which can be used for better management of T. tabaci in asparagus.

Control of the morphology and optical properties of ZnO nanostructures via hot mixing of reverse micelles.

ZnO nanostructures with controllable morphology were obtained by hot mixing reverse micelles containing Zn(NO(3))(2) or monoethanol amine aqueous solution. The ratio of water to surfactant concentration (omega(0)) was found to play a decisive role in determining the final morphology, namely, nanotetrahedrons formed at a lower omega(0) value and nanorods formed at a higher value. However, the hot mixing technique is propitious for obtaining nanostructures with uniform size. The ZnO nanotetrahedrons obtained gave a strong blue emission arising from interface state, and the ZnO nanorods emitted green light related to donor defects. Our results indicate that the hot mixing of reverse micelles is a unique way to tune the morphology and properties of nanostructures.

Stable aqueous dispersion of ZnO quantum dots with strong blue emission via simple solution route.

The aqueous dispersion of ZnO quantum dots (QDs) with strong blue emission (quantum yield of 76%) was synthesized through a simple solution route. The water stability of such QDs is provided by the hydroxyl groups on their surface, and the strong blue emission is suggested to arise from the formation of surface ZnO/oleic acid complexes. Under irradiation, these complexes are thought to absorb the excitation light with 3.54 eV and then generate the blue emission with 2.82 eV.