Polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in the equatorial Indian Ocean: Temporal trend, continental outflow and air-water exchange

Nineteen pairs of air and seawater samples collected from the equatorial Indian Ocean onboard the Shiyan I from 4/2011 to 5/2011 were analyzed for PCBs and HCB. Gaseous concentrations of Sigma(ICES)PCBs (ICES: International Council for the Exploration of the Seas) and HCB were lower than previous data over the study area. Air samples collected near the coast had higher levels of PCBs relative to those collected in the open ocean, which may be influenced by proximity to source regions and air mass origins. Dissolved concentrations of Sigma(ICES)PCBs and HCB were 1.4-14 pg L-1 and 0.94-13 pg L-1, with the highest concentrations in the sample collected from Strait of Malacca. Fugacity fractions suggest volatilization of PCBs and HCB from the seawater to air during the cruise, with fluxes of 0.45-34 ng m(-2) d(-1) and 0.36-18 ng m(-2) d(-1), respectively. (c) 2014 Elsevier Ltd. All rights reserved.Nineteen pairs of air and seawater samples collected from the equatorial Indian Ocean onboard the Shiyan I from 4/2011 to 5/2011 were analyzed for PCBs and HCB. Gaseous concentrations of Sigma(ICES)PCBs (ICES: International Council for the Exploration of the Seas) and HCB were lower than previous data over the study area. Air samples collected near the coast had higher levels of PCBs relative to those collected in the open ocean, which may be influenced by proximity to source regions and air mass origins. Dissolved concentrations of Sigma(ICES)PCBs and HCB were 1.4-14 pg L-1 and 0.94-13 pg L-1, with the highest concentrations in the sample collected from Strait of Malacca. Fugacity fractions suggest volatilization of PCBs and HCB from the seawater to air during the cruise, with fluxes of 0.45-34 ng m(-2) d(-1) and 0.36-18 ng m(-2) d(-1), respectively. (c) 2014 Elsevier Ltd. All rights reserved

Investigation and Application of Colored-leaf Plants in Tibet

For the quantitative analysis of colored-leaf plants in Tibet, the five-point sampling method is used for stratified investigation of garden plant communities in Tibet. (i) There are a total of 46 families, 76 genera and 110 species of garden colored-leaf plants in Tibet, including 56 kinds of trees, 40 kinds of bushes, 9 kinds of herbs, 4 kinds of vines and 1 kind of bamboo. There are too few colored-leaf herbs and bamboos, and there is a serious imbalance between evergreen and deciduous trees, between coniferous and broad leaved forests. (ii) The most widely applied families include Rosaceae (26), Salicaceae (12), Fabaceae (6), Aceraceae (5), Oleaceae (4) and Elaeagnaceae (4), accounting for 23.64%, 10.91%, 5.46%, 4.55%, 3.64% and 3.64% of the investigated colored-leaf plants, respectively. (iii) In terms of color, there are 55 kinds of red plants, 43 kinds of yellow plants and 12 kinds of plants with other colors, accounting for 50.00%, 39.09% and 10.91% of colored-leaf plants, respectively. There are 9 kinds of spring color leaf plants, 63 kinds of autumn color leaf plants, 29 kinds of constant color leaf plants, 7 kinds of double color leaf plants and 2 kinds of spot color leaf plants, accounting for 8.18%, 57.27%, 26.36%, 6.36% and 1.82% of colored-leaf plants, respectively, indicating that it is dominated by autumn color leaf and constant color leaf plants. (iv) In terms of importance value of trees, the top two are Salix alba (37.623) and Prunus cerasifera f.atropurpurea (26.063); in terms of importance value of bushes, the top three are Ligustrum×vicaryi Hort (22.577), Berberis thunbergii ‘atropurpurea Nana’ (18.987) and Platycladus orientalis Franco cv. Sieboldii (10.529); in terms of importance value of herbs, the top two are Taraxacum sherriffii (0.915) and Oxalis triangu laris cv. purpurea (0.326). (v) In terms of species abundance of colored-leaf plants, it is in the order of Nyingchi (94)>Lhasa (47)>Qamdo (43)>Shannan (34)>Xigaze (21)>Ali (7)>Nagqu (5). There are great differences between regions: it is highest in Nyingchi while it is lowest in Nagqu. Based on the main problems in the application of colored-leaf plants in Tibet, this paper makes the corresponding recommendations

Effects of the Vitamin D3 on Alleviating the Oxidative Stress Induced by Diquat in Wenchang Chickens

Vitamin D3 (VD3) is an indispensable micronutrient in livestock and poultry feed. Its function in antioxidant stress has been reported. We investigate whether the addition of different concentrations of VD3 to the diet affects the production performance, slaughter performance, meat quality, organ index, and gut injury on the diquat (DQ)-induced model of oxidative stress in Wenchang chickens. Four hundred and eighty one-day-old chickens were randomly divided into six groups: control (basal diet), 4000 VD (basal diet + VD3 4000 IU per kg feed intake), 1000 VD+DI (DQ, basal diet + VD3 1000 IU per kg feed intake), 2000 VD+DI (DQ, basal diet + VD3 2000 IU per kg feed intake), and 4000 VD+DI (DQ, basal diet + VD3 4000 IU per kg feed intake). The results showed that the addition of VD3 to the diet promoted DQ-induced weight loss and reduced ADFI, slaughter rate, splenic index, and pH after 1 h and 24 h in the leg muscles. VD3 decreased the increase in content of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) among proinflammatory cytokines (p 0.05) and increased the reduction in anti-inflammatory cytokines content of interleukin-10 (IL-10) (p 0.05) induced by DQ. In addition, liver and kidney injury biomarkers and the intestinal permeability index in serum were disordered after treatment with DQ (p 0.05). VD3 perfected the increase of D-lactic acid (D-LA), diamine oxidase (DAO), total cholesterol (T-CHO), creatinine (CR), blood urea nitrogen (BUN), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) content, aspartate transaminase (AST), alanine transaminase (ALT), and lactate dehydrogenase (LDH) activity (p 0.05); it increased the decrease of albumin (ALB) content (p 0.05). Meanwhile, VD3 regulated the intestinal morphology and intestinal barrier. Moreover, DQ induced a decrease in total antioxidant capacity and antioxidant enzyme activity in the serum, liver, and jejunum (p 0.05), and an increase in malonaldehyde (MDA) content (p 0.05). However, the addition of different levels of VD3 could alleviate the above phenomenon of oxidative stress in Wenchang chickens to different degrees. Thus, this research suggested that the addition of VD3 can relieve the DQ-induced oxidative stress of Wenchang chickens, and the level of VD3 acquisition is positively correlated with the remission effect

Data from: Mechanism and modelling of CO2 corrosion on downhole tools

The conditions surrounding oil and gas exploration are becoming more hazardous, especially in oil and gas fields with a high quantity of corrosive components such as CO2. CO2 causes localised corrosion of tools made from metal, rubber, and other materials in humid environments; this leads to corrosion failure in metal equipment and downhole tools such as drills pipes, casings, and oil pipes, thereby reducing their service life. In this study, the composition, lattice, and crystalline forms of corrosion products and corroded materials were analysed using scanning electron microscopy, energy spectrum analysis, X-ray diffraction, and polarization curves, in order to investigate the corrosion mechanisms and influential factors for several common tool materials. A CO2 corrosion model was established for two materials and the results were verified with optimal prediction values

Fossil and Non-fossil Fuel Sources of Organic and Elemental Carbonaceous Aerosol in Beijing, Shanghai, and Guangzhou: Seasonal Carbon Source Variation

We measured the radiocarbon isotope signals in various fractions of carbonaceous aerosols sampled across four seasons (Oct 2013–Jul 2014) in three megacities of China, viz., Beijing, Shanghai, and Guangzhou. The contributions of fossil fuel (FF) and non-fossil fuel (NF) to the carbonaceous aerosol were estimated based on the radiocarbon content in the organic carbon (OC), water-soluble organic carbon (WSOC), water-insoluble organic carbon (WIOC), and elemental carbon (EC). Although NF generated the primary share (> 55%) during autumn in all of the cities, the seasonal contributions of the sources differed by location during the rest of the year. During winter, FF emissions constituted the majority of the carbonaceous pollution (64%) in Beijing, probably as a result of increased coal combustion for heating. On average, the EC, WSOC, and WIOC generated by FF composed ~10%, 35%, and 19% of the total carbon (TC). Overall, NF was identified as the largest source of carbonaceous aerosol in Guangzhou (63%), whereas FF was the largest source, contributing slightly more than NF, in Shanghai (54%). During spring and summer, FF played a greater role than NF in Beijing (~55%) and Guangzhou (~63%); additionally, based on our limited number of samples, it contributed 71% in Shanghai during the latter season, with a significant portion due to fuel combustion (i.e., industrial, vehicular, fishing-boat, and large-vessel emissions)

Small RNA and Degradome Sequencing in Floral Bud Reveal Roles of miRNAs in Dormancy Release of <i>Chimonanthus praecox</i>

Chimonanthus praecox (wintersweet) is highly valued ornamentally and economically. Floral bud dormancy is an important biological characteristic in the life cycle of wintersweet, and a certain period of chilling accumulation is necessary for breaking floral bud dormancy. Understanding the mechanism of floral bud dormancy release is essential for developing measures against the effects of global warming. miRNAs play important roles in low-temperature regulation of flower bud dormancy through mechanisms that are unclear. In this study, small RNA and degradome sequencing were performed for wintersweet floral buds in dormancy and break stages for the first time. Small RNA sequencing identified 862 known and 402 novel miRNAs; 23 differentially expressed miRNAs (10 known and 13 novel) were screened via comparative analysis of breaking and other dormant floral bud samples. Degradome sequencing identified 1707 target genes of 21 differentially expressed miRNAs. The annotations of the predicted target genes showed that these miRNAs were mainly involved in the regulation of phytohormone metabolism and signal transduction, epigenetic modification, transcription factors, amino acid metabolism, and stress response, etc., during the dormancy release of wintersweet floral buds. These data provide an important foundation for further research on the mechanism of floral bud dormancy in wintersweet

Molecular insights into the reactivity of aquatic natural organic matter towards hydroxyl (•OH) and sulfate (SO4•−) radicals using FT-ICR MS

The higher scavenging capacity of natural organic matter (NOM) to hydroxyl radical ((OH)-O-center dot) than sulfate radical (SO4 center dot-) has been long-acknowledged. However, the difference in reactivity and the influence of initial characteristics, especially at the molecular-level, remain unaddressed. In this study, the reactivities of different NOM isolates to (OH)-O-center dot and SO4 center dot- were compared based on the determined second-order rate constants following the depletion of UV254-absorbing moieties. Three NOM isolates with varying characteristics were selected to investigate the influence of initial characteristics on their reactivities. With the identified reactive molecules using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the distinct reactivity between the radicals and the influence of the initial characteristics were illustrated. The reactivity towards SO4 center dot- was dominated by the electron density of the molecules (i.e., double bond equivalent (DBE)), while that of (OH)-O-center dot was also shaped by molecular size (i.e., m/z) and composition (i.e., N- or S-incorporation). The examination on the exclusively reactive molecules (accounting for 10-20%) reflected a preferred H-abstraction by (OH)-O-center dot and decarboxylation by SO4 center dot-. Moreover, the analysis on the shared reactive molecules (80-90%) based on the UV254 versus electron-donating capacity (EDC) dependency revealed a prevalent (OH)-O-center dot addition while single electron transfer to SO4 center dot-. The different reaction rates associated with the proposed transformation pathways supported the observed higher reactivity of NOM to (OH)-O-center dot than SO4 center dot-

Toxicity of biosynthesized silver nanoparticles to aquatic organisms of different trophic levels

Although biosynthesized nanoparticles are regarded as green products, research on their toxicity to aquatic food chains is scarce. Herein, biosynthesized silver nanoparticles (Alcea rosea-silver nanoparticles, AR-AgNPs) were produced by the reaction of Ag ions with leaf extract of herbal plant Alcea rosea. Then, the toxic effects of AR-AgNPs and their precursors such as Ag+ ions and coating agent (A.&nbsp;rosea leaf extract) on organisms of different trophic levels of a freshwater food chain were investigated. To the three studied aquatic organisms including phytoplankton (Chlorella vulgaris), zooplankton (Daphnia magna) and fish (Danio rerio), the coating agents of AR-AgNPs showed no toxic effects, and Ag+ ions were more toxic in comparison to AR-AgNPs. Further investigations revealed that the release of Ag+ ions from AR-AgNPs to the test media were not considerable due to the high stability of AR-AgNPs, thus the toxicity stemmed mainly from the particles of AR-AgNPs in all the three trophic levels. Based on values of 72-h EC50 for C.&nbsp;vulgaris, 48-h LC50 for D.&nbsp;magna and 96-h LC50 for D.&nbsp;rerio, the most sensitive organism to AR-AgNPs exposure was D.&nbsp;magna (the second trophic level)

Probing and Comparing the Photobromination and Photoiodination of Dissolved Organic Matter by Using Ultra-High-Resolution Mass Spectrometry

Photochemical halogenation of dissolved organic matter (DOM) may represent an important abiotic process for the formation of natural organobromine compounds (OBCs) and natural organoiodine compounds (OICs) within surface waters. Here we report the enhanced formation of OBCs and OICs by photohalogenating DOM in freshwater and seawater, as well as the noticeable difference in the distribution and composition pattern of newly formed OBCs and OICs. By using negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry, various OBCs and OICs were identified during the photohalogenation processes in sunlit waters. The respective number of OBCs and OICs formed in artificial seawater (ASW) under light radiation was higher than that in artificial freshwater (AFW), suggesting a possible role of the mixed reactive halogen species. OBCs were formed mainly via substitution reactions and addition reactions accompanied by other reactions and distributed into three classes: unsaturated hydrocarbons with relatively low oxygen content, unsaturated aliphatic compounds, and saturated fatty acids and carbohydrates with relatively high hydrogen content. Unlike the OBCs, OICs were located primarily in the region of carboxylic-rich alicyclic molecules composed of esterified phenolic, carboxylated, and fused alicyclic structures and were generated mainly through electrophilic substitution of the aromatic proton. Our findings call for further investigation on the exact structure and toxicity of the OBCs and OICs generated in the natural environment