Nitrous oxide research progress in polar and sub-polar oceans

N2O gas depletes ozone and has a powerful greenhouse effect. Oceans are among the most important N2O sources and have been the subject of extensive studies. Polar oceans are important regions for deep water formation and global-scale thermohaline circulation. Therefore, these water bodies play an important role in the N2O budget, however, these regions were not well studied. This review of previously published studies and data on polar oceans, including both the Arctic Ocean and Southern Ocean, describes the distribution pattern of N2O and possible regulating mechanism of these distribution patterns and shows that the Arctic Ocean and Southern Ocean both represent source and sink regions, suggesting that the source/sink characteristics of the Arctic and Southern oceans and their strengths need further study. Questions related to N2O circulation in polar oceans were proposed, and future work is suggested

Multiple processes affecting surface seawater N2O saturation anomalies in tropical oceans and Prydz Bay, Antarctica

We analyzed the N2O content of surface seawater sampled from Prydz Bay, Antarctica, on a cruise track between 30°S and 30°N during the twenty-second Chinese National Antarctic Research Expedition during austral summer, 2006. The surface water showed an average pN2O value of 311.9±7.6 nL·L-1 (14.1±0.4 nmol·L-1), which was slightly undersaturated. The air-sea N2O flux in the region was -0.3±0.8 μmol·m-2·d-1; however, N2O in the surface water was oversaturated in most stations along the cruise track. Saturation anomalies were greater than 10%, with a maximum of 54.7% being observed at the Equator, followed by 31% at 10°N in the Sulu Sea. The air-sea fluxes at these locations were 12.4 and 4 μmol·m-2·d-1, respectively. Overall, the results indicated that surface water in Prydz Bay was near equilibrium with atmospheric N2O, and that ocean waters in lower latitudes acted as a N2O source. Physical processes such as stratification, ice-melt water dilution, and solar radiation dominate the factors leading to N2O saturation of surface water of Prydz Bay, while biological production and upwelling are primarily responsible for the N2O oversaturation of surface water observed in subtropical and tropical regions along the cruise track

Concentration maxima of methane in the bottom waters over the Chukchi Sea shelf: implication of its biogenic source

Knowledge about the distribution of CH4 remains insufficient due to the scarcity of data in the Arctic shelves. We conducted shipboard observations over the Chukchi Sea shelf (CSS) in the western Arctic Ocean in September 2012 to obtain the distribution and source characteristics of dissolved CH4 in seawater. The oceanographic data indicated that a salinity gradient generated a pronounced pycnocline at depths of 20–30 m. The vertical diffusion of biogenic elements was restricted, and these elements were trapped in the bottom waters. Furthermore, high CH4 concentrations were measured below the pycnocline, and low CH4 concentrations were observed in the surface waters. The maximum concentrations of nutrients simultaneously occurred in the dense and cold bottom waters, and significant correlations were observed between CH4 and 2 3 SiO , 3 4 PO , 2 NO , and 4 NH (p < 0.01, n= 44). These results suggest that the production of CH4 in the CSS has a similar trend as that of nutrient regeneration and is probably associated with the degradation of organic matter. The high primary productivity and high concentration of organic matter support the formation of biogenic CH4 in the CSS and the subsequent release of CH4 to the water column

Adenomatoid Tumor of the Adrenal Gland: Report of Two Cases and Review of the Literature

Adenomatoid tumor (AT) is an uncommon benign neoplasm of mesothelial origin, usually occurring in the female and male genital tracts. Extragenital localization such as the adrenal gland is extremely rare. Until now, only 39 cases of adrenal AT have been reported in the English literature. Here we report two novel cases of adrenal AT that occurred in male patients aged 30 and 31 years. The tumors were discovered incidentally by computed tomography (CT). Macroscopically, the tumors were unilateral and solid, and the greatest dimension of the tumors was 3.5 and 8.0 cm, respectively. Histologically, the tumors consisted of angiomatoid, cystic, and solid patterns and infiltrated the adrenal cortical or medullary tissue. The tumor cells had low nuclear/cytoplasmic ratio, with no pathological mitosis or nuclear pleomorphism. Thread-like bridging strands and signet-ring-like cells could be seen. Immunohistochemically, the tumor cells were positive for epithelial markers (AE1/AE3, CK7) and mesothelial markers (D2-40, calretinin, and WT-1). The Ki-67 index was approximately 1 and 2%, respectively. The differential diagnosis of adrenal AT includes a variety of benign and malignant tumors. The patients had neither local recurrence nor distant metastasis at 21 and 8 months after removal of the tumor. In the literature review, we comprehensively summarized the clinical, morphological, immunohistochemical, and prognostic features of adrenal AT. Adrenal ATs are morphologically and immunophenotypically identical to those that occur in the genital tracts. Combining the histology with immunohistochemical profiles is very supportive in reaching the diagnosis of this benign tumor, helping to avoid misdiagnosis and overtreatment

RYBP Inhibits Progression and Metastasis of Lung Cancer by Suppressing EGFR Signaling and Epithelial-Mesenchymal Transition

Lung cancer (LC) is a common lethal malignancy with rapid progression and metastasis, and Ring1 and YY1 binding protein (RYBP) has been shown to suppress cell growth in human cancers. This study aimed to investigate the role of RYBP in LC progression and metastasis. In this study, a total of 149 LC patients were recruited, and the clinical stage of their tumors, metastasis status, survival time, presence of epidermal growth factor receptor (EGFR) mutation, and RYBP expression levels were measured. RYBP silencing and overexpression were experimentally performed in LC cell lines and in nude mice, and the expressions of genes in EGFR-related signaling pathways and epithelial-mesenchymal transition (EMT) were detected. The results showed that RYBP was downregulated in LC compared with adjacent normal tissues, and low RYBP expression was associated with a more severe clinical stage, high mortality, high metastasis risk, and poor survival. Cell proliferation and xenograft growth were inhibited by RYBP overexpression, whereas proliferation and xenograft growth were accelerated by RYBP silencing. EGFR and phosphorylated-EGFR levels were upregulated when RYBP was silenced, whereas EGFR, p-EGFR, p-AKT, and p-ERK were downregulated when RYBP was overexpressed. Low RYBP expression was related to a high metastasis risk, and metastasized tumors showed low RYBP levels. Cell migration and invasion were promoted by silencing RYBP but were inhibited by overexpressed RYBP. In addition, the EMT marker vimentin showed diminished expression, and E-cadherin was promoted by the overexpression of RYBP. In conclusion, our data suggest that RYBP suppresses cell proliferation and LC progression by impeding the EGFR-ERK and EGFR-AKT signaling pathways and thereby inhibiting cell migration and invasion and LC metastasis through the suppression of EMT

Nitrous oxide concentrations during CHINARE 36 cruise 2020

The data set comprises concentrations of dissolved N2O from seawater samples collected during the 36th Chinese Antarctic Research Expedition (36th CHINARE). The 36th CHINARE took place onboard the research vessel/icebreaker Xuelong 2 between the 3rd and 31st of January 2020 and focused on physical and biogeochemical surveys of the Ross Sea (Pacific sector of the Southern Ocean). Samples were collected by drawing water from 10 L Niskin bottles (installed on a standard CTD-Rosette) into brown borosilicate 20 mL vials, which were then sealed with rubber (butyl) stoppers and aluminium caps. Immediately after collection, samples were preserved by adding 0.05 mL of a saturated mercuric chloride solution. Samples were analyzed by means of a standard headspace method coupled to gas chromatography/electron capture detection. Details on the measurement equipment and data analysis can be found in Kock et al. (2016; see: www.biogeosciences.net/13/827/2016/)

Microstructure and properties of Ni-based self-lubricating coatings by laser cladding/friction stir processing

The KF-2-WC-CaF2\ua0Ni-based self-lubrication coatings were synthesized on the surface of 6061 aluminum alloy with preset powder by laser cladding / friction stir processing (FSP). OM, SEM, EDS and XRD were used to characterize the phase constituents, microstructure and properties of the coatings, and the micro-hardness distribution and wear properties were also analyzed. The results showed that smooth and good metallurgical bonding zone is formed between the coating and the substrate. The microstructure of the one-stepped coating is dendrite, cell crystal, columnar crystal and equiaxed crystal. The main phase constituents of the two-stepped coating consist of α-Ni, α-Al, AlNi3, Al3Ni2, WC and CaF2. And the micro-hardness is significantly higher than that by direct laser cladding. With the increase of distance between coating and stirring tool, mechanical effect gradually weakened, micro-hardness curve and friction coefficient showed a gradient feature along the thickness direction

Spatial Variability and Factors Influencing the Air-Sea N2O Flux in the Bering Sea, Chukchi Sea and Chukchi Abyssal Plain

The concentrations of the ozone-depleting greenhouse gas nitrous oxide (N2O) in the upper 300 m of the Subarctic and Arctic Oceans determined during the 5th Chinese National Arctic Research Expedition were studied. The surface water samples revealed that the study area could be divided into three regions according to the distribution of dissolved N2O in the surface water, namely, the Aleutian Basin (52° N–60° N), continental shelf (60° N–73° N) and Canadian Basin (north of 73° N), with N2O in the surface water in equilibrium, oversaturated and undersaturated relative to the atmosphere, respectively. The influences of physical and chemical processes, such as eddy diffusion and sedimentary emissions, beneath the surface layer are discussed. The results of a flux evaluation show that the Aleutian Basin may be a weak N2O source of approximately 0.46 ± 0.1 μmol·m−2·d−1, and the continental shelf acts as a strong N2O source of approximately 8.2 ± 1.4 μmol·m−2·d−1. By contrast, the Chukchi Abyssal Plain (CAP) of the Canadian Basin is at least a temporal N2O sink with a strength of approximately −10.2 ± 1.4 μmol·m−2·d−1

Preparation of North American Type II PRRSV Infectious Clone Expressing Green Fluorescent Protein

Porcine reproductive and respiratory syndrome virus (PRRSV) is still one of the most important infectious diseases threatening the swine industry. To construct North American type II PRRSV infectious clone containing green fluorescent protein (GFP) gene, we amplify gfp gene, flanked by PRRSV Nsp2 gene fragments upstream and downstream, using overlap PCR method from pcDNA-EF1-GFP plasmid and FL12 plasmid containing PRRSV infectious genome as the templates. The Nsp2 fragment-flanked gfp gene was inserted into Nsp2 gene of the FL12 plasmid by Spe I and Xho I sites to generate PRRSV infectious recombinant plasmid (FL12-GFP) containing gfp gene. The recombinant PRRSV expressing GFP (PRRSV-GFP) was rescued in baby hamster kidney-21 (BHK-21) cells by transfecting PRRSV mRNA synthesized in vitro and amplified in Marc-145 cells. The PRRSV-GFP infectivity and replication capacity were identified. Results showed that, by adopting overlap PCR strategy, the gfp gene was successfully inserted into and fused with PRRSV Nsp2 gene in the PRRSV infectious clone plasmid FL-12 to generate FL12-GFP plasmid. The recombinant PRRSV-GFP was generated through transfecting PRRSV mRNA in BHK-2 cells. Like its parental virus, the recombinant PRRSV-GFP maintains its infectivity to Marc-145 cells and porcine alveolar macrophages (PAMs). This study provides essential conditions for further investigation on PRRSV