Rational Design of Molybdenum-Doped Cobalt Nitride Nanowire Arrays for Robust Overall Water Splitting.

Rational design of efficient electrocatalysts is highly imperative but still a challenge for overall water splitting. Herein, we construct self-supported Co3 N nanowire arrays with different Mo doping contents by hydrothermal and nitridation processes that serve as robust electrocatalysts for overall water splitting. The optimal Co3 N-Mo0.2 /Ni foam (NF) electrode delivers a low overpotential of 97 mV at a current density of 50 mA cm-2 as well as a highly stable hydrogen evolution reaction (HER). Density functional theory (DFT) calculations prove that Mo doping can effectively modulate the electronic structure and surface adsorption energies of H2 O and hydrogen intermediates on Co3 N, leading to improved reaction kinetics with high catalytic activity. Further modification with FeOOH species on the surface of Co3 N-Mo0.2 /NF improves the oxygen evolution reaction (OER) performance benefiting from the synergistic effect of dual Co-Fe catalytic centers. As a result, the Co3 N-Mo0.2 @FeOOH/NF catalysts display outstanding OER catalytic performance with a low overpotential of 250 mV at 50 1 mA cm-2 . The constructed Co3 N-Mo0.2 /NF||Co3 N-Mo0.2 @FeOOH/NF water electrolyzer exhibits a small voltage of 1.48 V to achieve a high current density of 50 mA cm-2 at 80 °C, which is superior to most of the reported electrocatalysts. This work provides a new approach to developing robust electrode materials for electrocatalytic water splitting.

Carbon-encapsulated Co2P/P-modified NiMoO4 hierarchical heterojunction as superior pH-universal electrocatalyst for hydrogen production.

The development of hydrogen evolution reaction (HER) technology that operates stably in a wide potential of hydrogen (pH) range of electrolytes is particular important for large-scale hydrogen production. However, the rational design of low-cost and pH-universal electrocatalyst with high catalytic performance remains a huge challenge. Herein, Co2P nanoparticles strongly coupled with P-modified NiMoO4 nanorods are directly grown on nickel foam (NF) substrates through carbon layer encapsulation (denoted as C-Co2P@P-NiMoO4/NF) by hydrothermal, deposition, and phosphating processes. This novel kind of hierarchical heterojunction has abundant heterogeneous interfaces, strong electronic interactions, and optimized reaction kinetics, representing the highly-active pH-universal electrodes for HER. Remarkably, the C-Co2P@P-NiMoO4/NF catalyst shows excellent HER properties in acidic and basic electrolytes, where the overpotentials of 105 mV and 107 mV are applied to drive the current density of 100 mA cm-2. In addition, a low overpotential of 177 mV at 100 mA cm-2 along with high stability is realized in 1 M phosphate buffer solution (PBS), which is close to the state-of-the-art non-precious metal electrocatalysts. Our work not only provides a class of robust pH-universal electrocatalyst but also offers a novel way for the rational design of other heterogeneous materials bythe interface regulation strategy.

Universal strategy of iron/cobalt-based materials for boosted electrocatalytic activity of water oxidation.

Low-dimensional cobalt-based materials have proved to be one of the promising catalytic systems for oxygen-evolution reaction (OER). How to develop a facile and universal strategy for significantly improving their catalytic performance is of great significance, but still faces great challenges. Herein, a series of cobalt-based nanowires (CoS2, CoP, CoF2, and Co3O4) are synthesized and used as conceptual examples to explore the universality to enhance their OER catalytic activity. The FeOOH-modified cobalt-based electrocatalysts exhibit significantly improved OER catalytic performance compared to the pristine samples. Especially, the optimal CoS2@FeOOH material delivers the smallest overpotential of 260 mV at 100 mA cm-2, which outperforms most of the reported excellent materials. Notably, the CoP||CoP@FeOOH electrolyzer (1.63 V@30 mA cm-2) delivers higher performance than the CoS2||CoS2@FeOOH electrolyzer (1.72 V@30 mA cm-2) benefiting from the better HER catalytic activity of CoP. In addition, the post-characterizations confirm that the real catalytic structure of those electrocatalysts consists of a surface CoOOH@FeOOH catalytic layer and cobalt-based nanowire core. The Co-Fe catalytic layer provides more active centers for the adsorption and dissociation of water molecules as well as the formation of oxygen, while the nanowire core acts as an electron transport channel to realize better reaction kinetics. Our work not only develops a general strategy to enhance the catalytic activity but also provides new ideas for the facile design of other advanced catalytic materials.

Transcriptomics and Metabolomics Reveal Purine and Phenylpropanoid Metabolism Response to Drought Stress in Dendrobium sinense, an Endemic Orchid Species in Hainan Island.

Drought stress is a bottleneck factor for plant growth and development, especially in epiphytic orchids that absorb moisture mainly from the air. Recent studies have suggested that there are complex transcriptional regulatory networks related to drought stress in Dendrobium sinense. In this study, the transcription and metabolite alterations involved in drought stress response in D. sinense were investigated through RNA-seq and metabolomics. A total of 856 metabolites were identified from stressed and control samples, with 391 metabolites showing significant differences. With PacBio and Illumina RNA sequencing, 72,969 genes were obtained with a mean length of 2,486 bp, and 622 differentially expressed genes (DEGs) were identified. Correlation analysis showed 7 differential genes, and 39 differential metabolites were involved in interaction networks. The network analysis of differential genes and metabolites suggested that the pathways of purine metabolism and phenylpropanoid biosynthesis may play an important role in drought response in D. sinense. These results provide new insights and reference data for culturally important medicinal plants and the protection of endangered orchids.

Detection of carboxylesterase by a novel hydrosoluble near-infrared fluorescence probe.

A novel hydrosoluble near-infrared fluorescence off-on probe has been developed for detecting carboxylesterase activity. The probe was designed by introducing (4-acetoxybenzyl)oxy as a quenching and recognizing moiety to the decomposed product of IR-783, which exhibits excellent near-infrared fluorescence features and good water solubility. The responding mechanism of novel probe 1 to carboxylesterase was investigated. It would lead to the cleavage of the carboxylic ester bond by carboxylesterase catalyze the spontaneous hydrolysis of the probe, resulting in the release of a near-infrared fluorophore. This behaviour leads to the development of a simple and sensitive fluorescent method for assaying carboxylesterase activity, with a detection limit of 3.4 × 10-3 U mL-1. Moreover, the probe displays excellent selectivity toward carboxylesterase over other substances. Notably, the imaging experimental results showed that the probe 1 is cell membrane permeable, and its applicability has been demonstrated for monitoring carboxylesterase activity in HeLa cells.

Differentially Methylated Epiloci Generated from Numerous Genotypes of Contrasting Tolerances Are Associated with Osmotic-Tolerance in Rice Seedlings.

DNA methylation plays an essential role in plant responses to environmental stress. Since drought develops into a rising problem in rice cultivation, investigations on genome-wide DNA methylation in responses to drought stress and in-depth explorations of its association with drought-tolerance are required. For this study, 68 rice accessions were used for an evaluation of their osmotic-tolerance related to 20% PEG6000 simulated physiological traits. The tolerant group revealed significantly higher levels of total antioxidant capacity and higher contents of H2O2 in both normal and osmotic-stressed treatments, as well as higher survival ratios. We furthermore investigated the DNA methylation status in normal, osmotic-stressed, and re-watering treatments via the methylation-sensitive amplification polymorphism (MSAP). The averaged similarity between two rice accessions from tolerant and susceptible groups was approximately 50%, similar with that between two accessions within the tolerant/susceptible group. However, the proportion of overall tolerance-associated epiloci was only 5.2% of total epiloci. The drought-tolerant accessions revealed lower DNA methylation levels in the stressed condition and more de-methylation events when they encountered osmotic stress, compared to the susceptible group. During the recovery process, the drought-tolerant accessions possessed more re-methylation events. Fourteen differentially methylated epiloci (DME) were, respectively, generated in normal, osmotic-stressed, and re-watering treatments. Approximately, 35.7% DME were determined as tolerance-associated epiloci. Additionally, rice accessions with lower methylation degrees on DME in the stressed conditions had a higher survival ratio compared to these with higher methylation degrees. This result is consistent with the lower DNA methylation levels of tolerant accessions observed in the stressed treatment. Methylation degrees on a differentially methylated epilocus may further influence gene regulation in the rice seedling in response to the osmotic stress. All these results indicate that DME generated from a number of genotypes could have higher probabilityies for association with stress-tolerance, rather than DME generated from two genotypes of contrasting tolerance. The DME found in this study are suspected to be good epigenetic markers for the application in drought-tolerant rice breeding. They could also be a valuable tool to study the epigenetic differentiation in the drought-tolerance between upland and lowland rice ecotypes.

Occurrence and distribution of synthetic musks and organic UV filters from riverine and coastal sediments in the Pearl River estuary of China.

This study reports the occurrence and distribution of synthetic musks (SMs) and organic UV filters (UVFs) in sediment samples collected in 8 riverine runoffs from the Pearl River and Pearl River estuary (PRE). Here, 6 of the 8 target compounds were detected in all sediments with concentrations ranging from 0.35ngg(-1) to 456ngg(-1). Higher concentrations of SMs and UVFs were evident in the eastern outlets compared to the western suggesting greater input of these contaminants from the Pearl River Delta (PRD) region. All the compounds showed a decreasing trend toward the seaward side which confirming that riverine runoff was the most important source of SMs and UVFs to the coastal environment. Notably, high levels of SMs and UVFs were detected in two fishing harbors in the PRE area. In comparison to UVFs, the SM compounds exhibited a significant correlation with TOC content in the sediments.

Adaptive Epigenetic Differentiation between Upland and Lowland Rice Ecotypes Revealed by Methylation-Sensitive Amplified Polymorphism.

The stress-induced epimutations could be inherited over generations and play important roles in plant adaption to stressful environments. Upland rice has been domesticated in water-limited environments for thousands of years and accumulated drought-induced epimutations of DNA methylation, making it epigenetically differentiated from lowland rice. To study the epigenetic differentiation between upland and lowland rice ecotypes on their drought-resistances, the epigenetic variation was investigated in 180 rice landraces under both normal and osmotic conditions via methylation-sensitive amplified polymorphism (MSAP) technique. Great alterations (52.9~54.3% of total individual-locus combinations) of DNA methylation are recorded when rice encountering the osmotic stress. Although the general level of epigenetic differentiation was very low, considerable level of ΦST (0.134~0.187) was detected on the highly divergent epiloci (HDE). The HDE detected in normal condition tended to stay at low levels in upland rice, particularly the ones de-methylated in responses to osmotic stress. Three out of four selected HDE genes differentially expressed between upland and lowland rice under normal or stressed conditions. Moreover, once a gene at HDE was up-/down-regulated in responses to the osmotic stress, its expression under the normal condition was higher/lower in upland rice. This result suggested expressions of genes at the HDE in upland rice might be more adaptive to the osmotic stress. The epigenetic divergence and its influence on the gene expression should contribute to the higher drought-resistance in upland rice as it is domesticated in the water-limited environment.

Endocrine-disrupting chemicals in the Pearl River Delta and coastal environment: sources, transfer, and implications.

A study was conducted to investigate the occurrence and behavior of six endocrine-disrupting chemicals (EDCs) in sewage, river water, and seawater from the Pearl River Delta (PRD). The six EDCs under study were 4-nonylphenol (NP), bisphenol A (BPA), 17α-ethynylestradiol (EE2), estrone (E2), 17ß-estradiol (E2), and estriol (E3). These EDCs, predominated by BPA, were found in high levels in the influents and the effluents of sewage treatment plants in the area. The relatively high concentrations (0.23-625 ng/L) of the EDCs detected in the receiving river water suggested that the untreated sewage discharge was a major contributor. The EDCs detected in eight outlets of the Pear River and the Pear River Estuary were in the ranges of 1.2-234 and 0.2-178 ng/L, respectively. The estrogen equivalents in the aquatic environments under study ranged from 0.08 to 4.5 ng/L, with E1 and EE2 being the two predominant contributors. As the fluxes of the EDCs from the PRD region to the nearby ocean are over 500 tons each year, the results of this study point to the potential that Pearl River is a significant source of the EDCs to the local environment there.

Levels and distribution of heavy metals in atmospheric particular matters over the northern South China Sea.

Oceans play a significant role in the cycling of trace metals and persistent organic pollutants. In this study, aerosol samples covering the whole northern South China Sea (SCS) were collected in 2005 and 2007, respectively, for analysis of trace metals and major elements. The levels of trace metals detected ranged from 0.514 to 119 ng/m(3) in 2005 and from 0.130 to 24.2 ng/m(3) in 2007, respectively. Cu, Zn, and Pb were the three predominant metals with high enrichment factors (>10), indicating the strong anthropogenic inputs. The trace metals over SCS were comparable to the values in suburban and background sites of South China, but generally higher than those over other seas and oceans. Considering the fact that they were influenced by their proximity to source regions and air mass origins, the elevated metals in 2005 were probably attributed to the strong wind and long-range atmospheric transport driven by Asian monsoon.

[Effect of Curcuma aromatica on epithelial-myofibroblast transdifferentiation of NRK-52E cells induced by TGF-beta1].

OBJECTIVE: To observe the antagonist effect of Curcuma Aromatica (CA) on renal tubular epithelial-myofibroblast transdifferentiation (EMT) induced by transforming growth factor-beta1 (TGF-beta1). METHODS: Normal renal tubular epithelial NRK-52E cells in vitro cultured were randomly divided into 6 groups, i.e., the normal control group (Group C), the TGF-beta1 induced model group (Group T), the low dose CA treated group (Group E1), the moderate dose CA treated group (Group E2), the high dose CA group (Group E3), and the Benazepril Hydrochloride Tablet treated group (Group Y). Except Group C, corresponding medication (with an action of 48 h) was administered to cells in the rest groups after they were induced by TGF-beta1 for 24 h. The morphological changes were observed by inverted phase contrast microscope. The distribution of beta-actin protein was detected by immunohistochemical assay. The mRNA expressions of alpha-smooth muscle actin (alpha-SMA) and E-cadherin (E-cad) were detected by real-time PCR. The concentration of fibronectin (FN) was detected by ELISA. RESULTS: After induced by TGF-beta1 for three days, hypertrophy and elongated cells in fusiform-shape occurred,with increased expressions of beta-actin protein in the cytoskeletal structure (P < 0.05), bundle fibrous structure occurred inside cytoplasm with significantly up-regulated intracellular alpha-SMA mRNA expressions (P < 0.05), E-cad mRNA expression decreased (P < 0.05), the FN content in the supernate increased (P < 0.05) in Group T. Compared with Group T, partial cells in Group E1, E2, and E3 showed fibrous changes, accompanied with decreased expression of beta-actin protein and FN concentration (P < 0.05). The expression of alpha-SMA mRNA increased and the expression E-cad mRNA decreased in Group E2 and E3 (both P < 0.05). But there was no statistical difference in the expression levels of E-cad and alpha-SMA mRNA (P > 0.05). Compared with Group E1, the expression of beta-actin protein and FN concentration decreased in Group E2 and E3 (P < 0.05). The expressions of alpha-SMA mRNA decreased and E-cad mRNA increased in Group E3 (P < 0.05). Compared with Group Y, the expression of beta-actin mRNA and FN concentration increased in Group E1 (P < 0.05); the expression of beta-actin mRNA increased in Group E3 (P < 0.05); the expression of E-cad mRNA decreased in Group E3 (P < 0.05). There was no statistical difference in the expression of alpha-SMA mRNA among Group E1, E2, and E3 (P > 0.05). CONCLUSION: CA could inhibit the occurrence of TGF-beta1 induced EMT, which could be used as an effective drug for treating chronic renal insufficiency.

Antibiotics in riverine runoff of the Pearl River Delta and Pearl River Estuary, China: concentrations, mass loading and ecological risks.

Ten antibiotics belonging to three groups (macrolides, fluoroquinolones and sulfonamides) were investigated in riverine runoff of the Pearl River Delta (PRD) and Pearl River Estuary (PRE), South China for assessing the importance of riverine runoff in the transportation of contaminants from terrestrial sources to the open ocean. All antibiotics were detected in the eight outlets with concentrations ranging from 0.7 to 127 ng L(-1). The annual mass loadings of antibiotics from the PRD to the PRE and coast were 193 tons with 102 tons from the fluoroquinolone group. It showed that antibiotics decreased from the riverine outlets to the PRE and open ocean. Risk assessment showed that most of these antibiotics showed various ecological risks to the relevant aquatic organisms, in which ofloxacin (OFL), erythromycin (ETM) and ciprofloxacin (CIP) posed high ecological risks to the studied aquatic environments.

Mercury profiles in surface sediments from ten bays along the coast of Southern China.

Spatial and temporal variations of mercury (Hg) were investigated from ten representative bays along the coast of Southern China. The total Hg (THg) in surface sediments varied widely with concentrations from 25 to 264 ng/g. As a whole, Hg pollution in several bays occupied by busy sea traffic and industrial activities, such as Shantou (ST) Bay and Dapeng (DP) Bay were remarkably more serious than others, which reflected the direct effects of anthropogenic activities around the coastal areas. Hg variations in sediment cores clearly display upcore rising trend which obviously correlates with the trend of economic development and urbanization in the last five decades. No significant correlations were found between Hg and organic matter and particle size, suggesting that the distribution of Hg is not fully controlled by these variables.

Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments from Zhanjiang Bay and Leizhou Bay, South China.

The concentrations and spatial distribution of polycyclic aromatic hydrocarbons have been investigated in two adjacent bays of Zhanjiang and Leizhou, China. The total concentrations of the 16 USEPA priority PAHs were ranged from 41.96 to 933.90 ng/g dry weight with an average concentration of 315.98 ng/g and ranged from 21.72 to 319.61 ng/g with an average concentration of 103.91 ng/g in Zhanjiang and Leizhou Bays, respectively. The spatial distribution of PAHs was site-specific and appeared to be somewhat positively correlated with TOC and negatively correlated with sediment grain size in the two bays. The values of Phe/Ant, BaA/228 and InP/276 were higher than 10, less than 0.2, and from 0.2 to 0.5, respectively, indicating that the sources of PAHs in the two bays were mainly from petroleum and its combustion, which predominantly originated from those ships and boats coming and going in the two bays.

Spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments from Daya Bay, South China.

The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in Daya Bay, China. The total concentration of the 16 USEPA priority PAHs in surface sediments ranged from 42.5 to 158.2 ng/g dry weight with a mean concentration of 126.2 ng/g. The spatial distribution of PAHs was site-specific and combustion processes were the main source of PAHs in the surface sediments. Total 16 priority PAH concentration in the cores 8 and 10 ranged from 77.4 to 305.7 ng/g and from 118.1 to 319.9 ng/g respectively. The variation of the 16 PAH concentrations in both cores followed the economic development in China very well and was also influenced by input pathways. Some of the PAHs were petrogenic in core 8 while pyrolytic source was dominant in core 10. In addition, pyrolytic PAHs in both cores were mainly from the coal and/or grass and wood combustion.

Designing highly flexible and usable cyberinfrastructures for convergence.

This article presents the results of a 7-year-long quest into the development of a "dream tool" for our research in information science and scientometrics and more recently, network science. The results are two cyberinfrastructures (CI): The Cyberinfrastructure for Information Visualization and the Network Workbench that enjoy a growing national and interdisciplinary user community. Both CIs use the cyberinfrastructure shell (CIShell) software specification, which defines interfaces between data sets and algorithms/services and provides a means to bundle them into powerful tools and (Web) services. In fact, CIShell might be our major contribution to progress in convergence. Just as Wikipedia is an "empty shell" that empowers lay persons to share text, a CIShell implementation is an "empty shell" that empowers user communities to plug-and-play, share, compare and combine data sets, algorithms, and compute resources across national and disciplinary boundaries. It is argued here that CIs will not only transform the way science is conducted but also will play a major role in the diffusion of expertise, data sets, algorithms, and technologies across multiple disciplines and business sectors leading to a more integrative science.