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Liwei Wang, Cheng Wang, Zhihua Pan, Hui Xu, Lin Gao, Peiyi Zhao, Zhiqiang Dong, Jingting Zhang, Guohui Cui, Sen Wang, Guolin Han, Hui Zhao
Representing an important greenhouse gas, nitrous oxide (N2O) emission from cultivated land is a hot topic in current climate change research. This study examined the influences of nitrogen fertilisation, temperature and soil moisture on the ammonia monooxygenase subunit A (amoA) gene copy numbers and N2O emission characteristics. The experimental observation of N2O fluxes was based on the static chamber-gas chromatographic method. The ammonia-oxidising bacteria (AOB) and ammonia-oxidising archaea (AOA) gene copy numbers in different periods were measured by real-time polymerase chain reaction (PCR)...
December 3, 2016: International Journal of Biometeorology
Mark Trimmer, Panagiota-Myrsini Chronopoulou, Susanna T Maanoja, Robert C Upstill-Goddard, Vassilis Kitidis, Kevin J Purdy
Oceanic oxygen minimum zones are strong sources of the potent greenhouse gas N2O but its microbial source is unclear. We characterized an exponential response in N2O production to decreasing oxygen between 1 and 30 μmol O2 l(-1) within and below the oxycline using (15)NO2(-), a relationship that held along a 550 km offshore transect in the North Pacific. Differences in the overall magnitude of N2O production were accounted for by archaeal functional gene abundance. A one-dimensional (1D) model, parameterized with our experimentally derived exponential terms, accurately reproduces N2O profiles in the top 350 m of water column and, together with a strong (45)N2O signature indicated neither canonical nor nitrifier-denitrification production while statistical modelling supported production by archaea, possibly via hybrid N2O formation...
December 1, 2016: Nature Communications
Hannah Gaimster, Lisa Chalklen, Mark Alston, John T Munnoch, David J Richardson, Andrew J Gates, Gary Rowley
Nitrous oxide (N2O) is a stable, ozone depleting greenhouse gas. Emissions of N2O into the atmosphere continue to rise, primarily due to the use of nitrogen-containing fertilizers by soil denitrifying microbes. It is clear more effective mitigation strategies are required to reduce emissions. One way to help develop future mitigation strategies is to address the currently poor understanding of transcriptional regulation of the enzymes used to produce and consume N2O. With this ultimate aim in mind we performed RNA-seq on a model soil denitrifier, Paracoccus denitrificans, cultured anaerobically under high N2O and low N2O emitting conditions, and aerobically under zero N2O emitting conditions to identify small RNAs (sRNAs) with potential regulatory functions transcribed under these conditions...
2016: Frontiers in Microbiology
Huaihai Chen, Fangbo Yu, Wei Shi
Fungal denitrification has been increasingly investigated, but its community ecology is poorly understood due to the lack of culture-independent tools. In this work, four pairs of nirK-targeting primers were designed and evaluated for primer specificity and efficiency using thirty N2O-producing fungal cultures and an agricultural soil. All primers amplified nirK from fungi and soil, but their efficiency and specificity were different. A primer set, FnirK_F3/R2 amplified ∼80 % of tested fungi, including Aspergillus, Fusarium, Penicillium, and Trichoderma, as compared to ∼40-70 % for other three primers...
December 2016: Fungal Biology
Giorgio Mannina, Marco Capodici, Alida Cosenza, Daniele Di Trapani, Vito Armando Laudicina, Hallvard Ødegaard
The present paper reports the results of a nitrous oxide (N2O) production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the University of Cape Town layout for biological phosphorous removal. Gaseous and liquid samples were collected in order to measure the gaseous as well as the dissolved concentration of N2O. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated. The results confirmed that the anoxic reactor represents the main source of nitrous oxide production...
November 22, 2016: Journal of Environmental Management
Zhengrong Yao, Kun Tang, Zhonghua Xu, Jiandong Ye, Shunming Zhu, Shulin Gu
Vertically aligned N-doped ZnO microrods with a hexagonal symmetry were fabricated via the chemical vapor transport with abundant N2O as both O and N precursors. We have demonstrated the suppression of the zinc interstitial-related shallow donor defects and have identified the zinc vacancy-related shallow and deep acceptor states by temperature variable photoluminescence in O-rich growth environment. Through spatially resolved cathodoluminescence spectra, we found the luminescent inhomogeneity in the sample with a core-shell structure...
December 2016: Nanoscale Research Letters
Sunchai Theerapongpakdee, Thepakorn Sathitkarnmanee, Sirirat Tribuddharat, Siwalai Sucher, Maneerat Thananun, Duangthida Nonlhaopol
BACKGROUND: The Lack's circuit is a co-axial Mapleson A breathing system commonly used in spontaneously breathing anesthetized adults but still requires high fresh gas flow (FGF). The Lack-Plus circuit was invented with the advantage of lower FGF requirement. The authors compared the Lack-Plus and Lack's circuit for the minimal FGF requirement with no rebreathing in spontaneously breathing anesthetized adults. METHODS: This was a randomized crossover study. We enrolled 24 adult patients undergoing supine elective surgery, with a body mass index ≤30 kg/m(2) and an American Society of Anesthesiologists physical status I-II...
2016: Medical Devices: Evidence and Research
Lesley E Bobb, Michaela K Farber, Catherine McGovern, William Camann
STUDY OBJECTIVE: To compare the rate of epidural use before and after the implementation of nitrous oxide (N2O). DESIGN: Data were obtained from a nursing database of N2O usage and our obstetric anesthesia database. We compared 8 months before and 8 months after the introduction of N2O. It was available 24 h/d, 7 d/wk, consistent with neuraxial analgesia availability. Epidural utilization before and after introduction of N2O was compared using χ(2) analysis. SETTING: Labor and delivery floor...
December 2016: Journal of Clinical Anesthesia
T Wesley Templeton, Lauren K Hoke, Leah B Templeton, Douglas G Ririe, Danielle M Rose, Yvon F Bryan
STUDY OBJECTIVE: To determine quantitative differences in several routinely measured ventilation parameters using a standardized anesthetic technique and 3 different ventilation modalities in patients younger than 1 year with a ProSeal laryngeal mask airway (PLMA). DESIGN: Randomized prospective study. SETTING: Tertiary care pediatric hospital. PATIENTS: Thirty-nine American Society Anesthesiologists classifications 1 to 2, pediatric patients younger than 1 year...
December 2016: Journal of Clinical Anesthesia
Shinichi Yamashita, Jun Ma, Jean-Louis Marignier, Akihiro Hiroki, Mitsumasa Taguchi, Mehran Mostafavi, Yosuke Katsumura
We performed studies on pulse radiolysis of highly transparent and shape-stable hydrogels of hydroxypropyl cellulose (HPC) that were prepared using a radiation-crosslinking technique. Several fundamental aspects of radiation-induced chemical reactions in the hydrogels were investigated. With radiation doses less than 1 kGy, degradation of the HPC matrix was not observed. The rate constants of the HPC composing the matrix, with two water decomposition radicals [hydroxyl radical ((•)OH) and hydrated electron ([Formula: see text])] in the gels, were determined to be 4...
November 21, 2016: Radiation Research
Wei Wang, Xiaohong Wu, Anlei Chen, Xiaoli Xie, Yunqiu Wang, Chunmei Yin
The in situ application of rice straw enhances CH4 emissions by a large margin. The ex situ application of rice straw in uplands, however, may mitigate total global warming potential (GWP) of CH4 and N2O emissions from paddy-upland coexisting systems. To evaluate the efficiency of this practice, two field trials were conducted in rice-rice-fallow and maize-rape cropping systems, respectively. Year-round measurements of CH4 and N2O emissions were conducted to evaluate the system-scaled GWP. The results showed that CH4 accounted for more than 98% of GWP in paddy...
November 21, 2016: Scientific Reports
Shuping Qin, Timothy Clough, Jiafa Luo, Nicole Wrage-Mönnig, Oene Oenema, Yuming Zhang, Chunsheng Hu
Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) has greatly contributed to increased food production. However, enriching the biosphere with Nr has also caused a series of negative effects on global ecosystems, especially aquatic ecosystems. The main pathway converting Nr back into the atmospheric N2 pool is the last step in the denitrification process. Despite several attempts, there is still a need for perturbation-free methods for measuring in situ N2 fluxes from denitrification in aquatic ecosystems at the field scale...
November 12, 2016: Water Research
Zhi-Qi Lin, Shi-Jie Yuan, Wen-Wei Li, Jie-Jie Chen, Guo-Ping Sheng, Han-Qing Yu
Since nitrate causes severe ecological and health risks, nitrate contamination of drinking water sources has become one of the most important water quality concerns all over the world. Photocatalytic reduction of nitrate to molecular nitrogen presents a promising approach to remove nitrate from drinking water sources. However, harmful intermediates like NO2(-), NO, NO2 and N2O are usually formed, and metal loading or hole scavengers are generally needed to reduce the recombination of photo-generated electrons and holes, which will cause secondary pollution to drinking water...
November 14, 2016: Water Research
Lin Zhang, Christian Trncik, Susana L A Andrade, Oliver Einsle
The copper-containing enzyme nitrous oxide reductase (N2OR) catalyzes the transformation of nitrous oxide (N2O) to dinitrogen (N2) in microbial denitrification. Several accessory factors are essential for assembling the two copper sites CuA and CuZ and for maintaining their activity. In particular, the deletion of either the transmembrane iron-sulfur flavoprotein NosR or the periplasmic protein NosX, a member of the ApbE family, abolishes N2O respiration. Here we demonstrate through biochemical and structural studies that the ApbE protein from Pseudomonas stutzeri, where the nosX gene is absent, is a monomeric FAD-binding protein that can serve as the flavin donor for NosR maturation via covalent flavinylation of a threonine residue...
November 15, 2016: Biochimica et Biophysica Acta
Paul A Stricker, Wallis T Muhly, Ellen C Jantzen, Yue Li, Abbas F Jawad, Alexander S Long, Marcia Polansky, Scott D Cook-Sather
BACKGROUND: Bilateral myringotomy and pressure equalization tube insertion (BMT) is the most common surgery in children. Multiple anesthetic techniques for BMT have been proposed, but that which reliably promotes ideal recovery remains unclear. We sought to assess associations between anesthetic regimens that included single-agent (fentanyl or ketorolac) or dual-agent (fentanyl and ketorolac) analgesic therapy and the primary outcome of maximal postanesthesia care unit (PACU) pain score...
November 17, 2016: Anesthesia and Analgesia
Jonathan D Caranto, Avery C Vilbert, Kyle M Lancaster
Ammonia oxidizing bacteria (AOB) are major contributors to the emission of nitrous oxide (N2O). It has been proposed that N2O is produced by reduction of NO. Here, we report that the enzyme cytochrome (cyt) P460 from the AOB Nitrosomonas europaea converts hydroxylamine (NH2OH) quantitatively to N2O under anaerobic conditions. Previous literature reported that this enzyme oxidizes NH2OH to nitrite ([Formula: see text]) under aerobic conditions. Although we observe [Formula: see text] formation under aerobic conditions, its concentration is not stoichiometric with the NH2OH concentration...
November 16, 2016: Proceedings of the National Academy of Sciences of the United States of America
Hung-Ju Chen, Chih-Shan Huang
PURPOSE: Nitrous oxide (N2O) is neurotoxic by interfering with vitamin B12 bioavailability. The clinical picture is indistinguishable to that of subacute combined degeneration (SCD). A movement disorder might occur though it is not a characteristic feature. We report a patient with N2O-induced SCD, exhibiting a combination of different involuntary movements. CASE REPORT: A 20-year-old woman presented with one month of progressive unsteady gait, involuntary movements and tingling sensation in a stocking-glove distribution...
June 15, 2016: Acta Neurologica Taiwanica
Mengyao Gui, Qian Chen, Tao Ma, Maosheng Zheng, Jinren Ni
Effects of heavy metals on aerobic denitrification have been poorly understood compared with their impacts on anaerobic denitrification. This paper presented effects of four heavy metals (Cd(II), Cu(II), Ni(II), and Zn(II)) on aerobic denitrification by a novel aerobic denitrifying strain Pseudomonas stutzeri PCN-1. Results indicated that aerobic denitrifying activity decreased with increasing heavy metal concentrations due to their corresponding inhibition on the denitrifying gene expression characterized by a time lapse between the expression of the nosZ gene and that of the cnorB gene by PCN-1, which led to lower nitrate removal rate (1...
November 16, 2016: Applied Microbiology and Biotechnology
Muthuraman Vasanth, Moturi Muralidhar, Ramamoorthy Saraswathy, Arunachalam Nagavel, Jagabattula Syama Dayal, Marappan Jayanthi, Natarajan Lalitha, Periyamuthu Kumararaja, Koyadan Kizhakkedath Vijayan
Global warming/climate change is the greatest environmental threat of our time. Rapidly developing aquaculture sector is an anthropogenic activity, the contribution of which to global warming is little understood, and estimation of greenhouse gases (GHGs) emission from the aquaculture ponds is a key practice in predicting the impact of aquaculture on global warming. A comprehensive methodology was developed for sampling and simultaneous analysis of GHGs, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from the aquaculture ponds...
December 0: Environmental Monitoring and Assessment
Haixin Chen, Jingjing Liu, Afeng Zhang, Jing Chen, Gong Cheng, Benhua Sun, Xiaomin Pi, Miles Dyck, Bingcheng Si, Ying Zhao, Hao Feng
Mulching practices have long been used to modify the soil temperature and moisture conditions and thus potentially improve crop production in dryland agriculture, but few studies have focused on mulching effects on soil gaseous emissions. We monitored annual greenhouse gas (GHG) emissions under the regime of straw and plastic film mulching using a closed chamber method on a typical winter-wheat (Triticum aestivum L. cv Xiaoyan 22) and summer-maize (Zea mays L. cv Qinlong 11) rotation field over two-year period in the Loess Plateau, northwestern China...
November 12, 2016: Science of the Total Environment
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