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https://www.readbyqxmd.com/read/29149758/oligotrophy-as-a-major-driver-of-mercury-bioaccumulation-in-medium-to-high-trophic-level-consumers-a-marine-ecosystem-comparative-study
#1
Tiphaine Chouvelon, Pierre Cresson, Marc Bouchoucha, Christophe Brach-Papa, Paco Bustamante, Sylvette Crochet, Françoise Marco-Miralles, Bastien Thomas, Joël Knoery
Mercury (Hg) is a global contaminant of environmental concern. Numerous factors influencing its bioaccumulation in marine organisms have already been described at both individual and species levels (e.g., size or age, habitat, trophic level). However, few studies have compared the trophic characteristics of ecosystems to explain underlying mechanisms of differences in Hg bioaccumulation and biomagnification among food webs and systems. The present study aimed at investigating the potential primary role of the trophic status of systems on Hg bioaccumulation and biomagnification in temperate marine food webs, as shown by their medium-to high-trophic level consumers...
November 14, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/29149751/massive-arrival-of-desalinated-seawater-in-a-regional-urban-water-cycle-a-multi-isotope-study-b-s-o-h
#2
W Kloppmann, Ido Negev, Joseph Guttman, Orly Goren, Ittai Gavrieli, Catherine Guerrot, Christine Flehoc, Marie Pettenati, Avihu Burg
"Man-made" or unconventional freshwater, like desalinated seawater or reclaimed effluents, is increasingly introduced into regional water cycles in arid or semi-arid countries. We show that the breakthrough of reverse osmosis-derived freshwater in the largely engineered water cycle of the greater Tel Aviv region (Dan Region) has profoundly changed previous isotope fingerprints. This new component can be traced throughout the system, from the drinking water supply, through sewage, treated effluents, and artificially recharged groundwater at the largest Soil-Aquifer Treatment system in the Middle East (Shafdan) collecting all the Dan region sewage...
November 14, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29149554/boron-dissolved-and-dust-atmospheric-inputs-to-a-forest-ecosystem-northeastern-france
#3
Philippe Roux, Marie Pierre Turpault, Gil Kirchen, Paul-Olivier Redon, Damien Lemarchand
Boron concentrations and isotopic compositions of atmospheric dust and dissolved depositions were monitored over a two-years period (2012-2013) in the forest ecosystem of Montiers (Northeastern France). This time series allows the determination of the boron atmospheric inputs to this forest ecosystem and contributes to refine our understanding of the sources and processes that control the boron atmospheric cycle. Mean annual dust and dissolved boron atmospheric depositions are comparable in size (13 g.ha-1...
November 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29149444/morphology-molecular-structure-and-stable-carbon-isotopic-composition-of-black-carbon-bc-in-urban-topsoils
#4
Yutong Zong, Qing Xiao, Shenggao Lu
Urban soils contain significant amounts of black carbon (BC) from biomass and fossil fuel combustion and regard to be a pool of BC. BC in urban soils has multiple effects on environmental processes in urban system, such as global climate change, air quality, and public health. Urban topsoil samples (0-10 cm) were collected from Anshan, Liaoning Province, northeast China, which is one of the most important old steel industrial bases in China. The BC in urban topsoils was extracted using the density method. Their chemical composition, morphology, molecular structure, and stable carbon isotopic composition were examined using elemental analysis, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and stable carbon isotope (δ(13)C)...
November 17, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29148779/hydrogen-uptake-on-coordinatively-unsaturated-metal-sites-in-vsb-5-revisited-strong-binding-affinity-leading-to-high-temperature-d2-h2-selectivity
#5
Amit Sharma, Keith V Lawler, Jarod J Wolffis, Christopher T Eckdahl, Cooper S McDonald, Jesse L C Rowsell, Stephen A Fitzgerald, Paul M Forster
We examine the adsorption of hydrogen and deuterium into the nanoporous nickel phosphate, VSB-5. Based on gas sorption analysis, VSB-5 exhibits one of the highest measured H2 heats of adsorption (HOA) for hydrogen (16 kJ/mol) yet reported. This high HOA is consistent with an unusually large redshift in the Q(1) and Q(0) hydrogen vibrational modes as measured with in situ IR spectroscopy. The HOA for D2 is measured to be 2 kJ/mol higher than for H2. Ideal Adsorbed Solution Theory analysis of H2 and D2 isotherms provides selectivities above 4 for deuterium at 140 K, suggesting that VSB-5 is a promising adsorbent for pressure-swing adsorption type separations of hydrogen isotopes...
November 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29148746/keto-enol-tautomerization-triggers-an-electrophilic-aldehyde-deformylation-reaction-by-a-nonheme-manganese-iii-peroxo-complex
#6
Fabián G Cantú Reinhard, Prasenjit Barman, Gourab Mukherjee, Jitendra Kumar, Deep Kumar, Devesh Kumar, Chivukula V Sastri, Sam P de Visser
Oxygen atom transfer by high-valent enzymatic intermediates remains an enigma in chemical catalysis. In particular, manganese is an important first-row metal involved in key biochemical processes including the biosynthesis of mo-lecular oxygen (through the photosystem II complex) and biodegradation of toxic superoxide to hydrogen peroxide by superoxide dismutase. Biomimetic models of these biological systems have been developed to gain understanding on the structure and properties of short-lived intermediates but also with the aim to create environmentally benign oxidants...
November 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29146748/stable-isotope-kinetic-study-of-apom-apolipoprotein-m
#7
Mikaël Croyal, Stéphanie Billon-Crossouard, Sophie Goulitquer, Audrey Aguesse, Luis León, Fanta Fall, Maud Chétiveaux, Thomas Moyon, Valentin Blanchard, Khadija Ouguerram, Gilles Lambert, Estelle Nobécourt, Michel Krempf
OBJECTIVE: ApoM (apolipoprotein M) binds primarily to high-density lipoprotein before to be exchanged with apoB (apolipoprotein B)-containing lipoproteins. Low-density lipoprotein (LDL) receptor-mediated clearance of apoB-containing particles could influence plasma apoM kinetics and decrease its antiatherogenic properties. In humans, we aimed to describe the interaction of apoM kinetics with other components of lipid metabolism to better define its potential benefit on atherosclerosis...
November 16, 2017: Arteriosclerosis, Thrombosis, and Vascular Biology
https://www.readbyqxmd.com/read/29146204/mercury-exposure-and-short-term-consequences-on-physiology-and-reproduction-in-antarctic-petrels
#8
Alice Carravieri, Jérôme Fort, Arnaud Tarroux, Yves Cherel, Oliver P Love, Solène Prieur, Maud Brault-Favrou, Paco Bustamante, Sébastien Descamps
Mercury (Hg) is a pervasive contaminant reaching Antarctic environments through atmospheric transport and deposition. Seabirds as meso to top predators can accumulate high quantities of Hg through diet. Reproduction is one of the most sensitive endpoints of Hg toxicity in marine birds. Yet, few studies have explored Hg exposure and effects in Antarctic seabirds, where increasing environmental perturbations challenge animal populations. This study focuses on the Antarctic petrel Thalassoica antarctica from Svarthamaren, Antarctica, where the world's largest breeding population is thought to be in decline...
November 13, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/29145098/a-novel-simplified-strategy-of-relative-quantification-n-glycan-quantitative-glycomics-using-electrospray-ionization-mass-spectrometry-through-the-stable-isotopic-labeling-by-transglycosylation-reaction-of-mutant-enzyme-endo-m-n175q
#9
Qing Shi, Ryugo Hashimoto, Tadamune Otsubo, Kiyoshi Ikeda, Kenichiro Todoroki, Hajime Mizuno, Dongri Jin, Toshimasa Toyo'oka, Zhe Jiang, Jun Zhe Min
The lack of a highly sensitive and simple method for the quantitative analysis of glycan has impeded the exploration of protein glycosylation patterns (glycomics), evaluation of antibody drug stability, and screening of disease glycan biomarkers. In this study, we describe a novel and simplified quantitative glycomics strategy. Quantitation by mutant enzyme reaction stable isotope labeling (QMERSIL) to label the N-glycans with either a nondeuterated (d0-) or deuterated (d8-) 4-(2,4-Dinitro-5-piperazin-1-yl-phenyl)-1,1-dimethyl-piperazin-1-ium (MPDPZ)-Boc-asparaginyl-N-acetyl-d-glucosamine (Boc-Asn-GlcNAc) acceptor of a positive charge structure through the glycosynthase (Endo-M-N175Q) transglycosylation reaction with mass spectrometry facilitates comparative glycomics...
November 12, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/29144762/enhancement-of-co-evolution-by-modification-of-ga2o3-with-rare-earth-elements-for-the-photocatalytic-conversion-of-co2-by-h2o
#10
Hiroyuki Tatsumi, Kentaro Teramura, Zeai Huang, Zheng Wang, Hiroyuki Asakura, Saburo Hosokawa, Tsunehiro Tanaka
Modification of the surface of Ga2O3 with rare-earth elements enhanced the evolution of CO as a reduction product in the photocatalytic conversion of CO2 using H2O as an electron donor under UV irradiation in aqueous NaHCO3 as a pH buffer, with the rare-earth species functioning as a CO2 capture and storage material. Isotope experiments using (13)CO2 as a substrate clearly revealed that CO was generated from the introduced gaseous CO2. In the presence of the NaHCO3 additive, the rare-earth (RE) species on the Ga2O3 surface are transformed into carbonate hydrates (RE2(CO3)3•nH2O) and/or hydroxycarbonates (RE2(OH)2(3-x)(CO3)x) which are decomposed upon photoirradiation...
November 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29143948/label-free-nmr-based-dissociation-kinetics-determination
#11
Pablo Trigo-Mouriño, Christian Griesinger, Donghan Lee
Understanding the dissociation of molecules is the basis to modulate interactions of biomedical interest. Optimizing drugs for dissociation rates is found to be important for their efficacy, selectivity, and safety. Here, we show an application of the high-power relaxation dispersion (RD) method to the determination of the dissociation rates of weak binding ligands from receptors. The experiment probes proton RD on the ligand and, therefore, avoids the need for any isotopic labeling. The large ligand excess eases the detection significantly...
November 16, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/29143883/rooting-depth-varies-differentially-in-trees-and-grasses-as-a-function-of-mean-annual-rainfall-in-an-african-savanna
#12
Ricardo M Holdo, Jesse B Nippert, Michelle C Mack
A significant fraction of the terrestrial biosphere comprises biomes containing tree-grass mixtures. Forecasting vegetation dynamics in these environments requires a thorough understanding of how trees and grasses use and compete for key belowground resources. There is disagreement about the extent to which tree-grass vertical root separation occurs in these ecosystems, how this overlap varies across large-scale environmental gradients, and what these rooting differences imply for water resource availability and tree-grass competition and coexistence...
November 16, 2017: Oecologia
https://www.readbyqxmd.com/read/29143845/pulse-laser-induced-fragmentation-of-carbon-quantum-dots-a-structural-analysis
#13
Han-Wei Chu, Ju-Yi Mao, Chia-Wen Lien, Pang-Hung Hsu, Yu-Jia Li, Jui-Yang Lai, Tai-Chia Chiu, Chih-Ching Huang
Carbon quantum dots (CQDs) have attracted enormous interest in recent years owing to their low cytotoxicity, excellent biocompatibility and strong fluorescence. They have been successfully employed in sensor, bio-imaging, and drug carrier applications. A complete understanding of their core-surface structure is essential for tuning their physical and chemical properties for various applications. Conventional characterizations of CQDs are conducted with electron microscopy or spectroscopy, such as transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy...
November 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/29143368/re-thinking-the-role-of-radiometal-isotopes-towards-a-future-concept-for-theranostic-radiopharmaceuticals
#14
Johannes Notni, Hans-Jürgen Wester
The potential and future role of certain metal radionuclides, for example, (44) Sc, (89) Zr, (86) Y, (64) Cu, (68) Ga, (177) Lu, (225) Ac, (213) Bi, and several terbium isotopes has been controversely discussed in the past decades. Furthermore, the possible benefits of "matched pairs" of isotopes for tandem applications of diagnostics and therapeutics (theranostics) have been emphasized, while such approaches still haven't made their way into routine clinical practice. Analysis of bibliographical data illustrates how popularity of certain nuclides has been promoted by cycles of availability and applications...
November 16, 2017: Journal of Labelled Compounds & Radiopharmaceuticals
https://www.readbyqxmd.com/read/29143260/combining-stable-carbon-isotope-analysis-and-petroleum-fingerprinting-to-evaluate-petroleum-contamination-in-the-yanchang-oilfield-located-on-loess-plateau-in-china
#15
Yiping Wang, Jidong Liang, Jinxing Wang, Sha Gao
This study evaluated petroleum contamination in the Yanchang (Shaanxi Yanchang Petroleum (Group) Co., Ltd.) oilfield, located in the loess plateau region of northern Shaanxi, China. Surface soil and sediment samples were collected from the wasteland, farmland, and riverbed in this area to assess the following parameters: total petroleum hydrocarbon (TPH), n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and carbon isotope ratios (δ(13)C). The results showed that TPH and PAH levels in the study area were 907-3447 mg/kg and 103...
November 15, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/29142823/investigation-of-useful-carbon-tracers-for-13-c-metabolic-flux-analysis-of-escherichia-coli-by-considering-five-experimentally-determined-flux-distributions
#16
Kousuke Maeda, Nobuyuki Okahashi, Yoshihiro Toya, Fumio Matsuda, Hiroshi Shimizu
The (13)C-MFA experiments require an optimal design since the precision or confidence intervals of the estimated flux levels depends on factors such as the composition of (13)C-labeled carbon sources, as well as the metabolic flux distribution of interest. In this study, useful compositions of (13)C-labeled glucose for (13)C-metabolic flux analysis ((13)C-MFA) of Escherichia coli are investigated using a computer simulation of the stable isotope labeling experiment. Following the generation of artificial mass spectra datasets of amino acid fragments using five literature-reported flux distributions of E...
December 2016: Metabolic Engineering Communications
https://www.readbyqxmd.com/read/29142325/origin-of-methane-rich-natural-gas-at-the-west-pacific-convergent-plate-boundary
#17
Yuji Sano, Naoya Kinoshita, Takanori Kagoshima, Naoto Takahata, Susumu Sakata, Tomohiro Toki, Shinsuke Kawagucci, Amane Waseda, Tefang Lan, Hsinyi Wen, Ai-Ti Chen, Hsiaofen Lee, Tsanyao F Yang, Guodong Zheng, Yama Tomonaga, Emilie Roulleau, Daniele L Pinti
Methane emission from the geosphere is generally characterized by a radiocarbon-free signature and might preserve information on the deep carbon cycle on Earth. Here we report a clear relationship between the origin of methane-rich natural gases and the geodynamic setting of the West Pacific convergent plate boundary. Natural gases in the frontal arc basin (South Kanto gas fields, Northeast Japan) show a typical microbial signature with light carbon isotopes, high CH4/C2H6 and CH4/(3)He ratios. In the Akita-Niigata region - which corresponds to the slope stretching from the volcanic-arc to the back-arc -a thermogenic signature characterize the gases, with prevalence of heavy carbon isotopes, low CH4/C2H6 and CH4/(3)He ratios...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29142088/muscle-glycogen-synthesis-and-breakdown-are-both-impaired-in-glycogenin-1-deficiency
#18
Mads Godtfeldt Stemmerik, Karen Lindhardt Madsen, Pascal Laforêt, Astrid Emilie Buch, John Vissing
OBJECTIVE: To study fat and carbohydrate metabolism during exercise in patients with glycogenin-1 (GYG1) deficiency, and to study whether IV glucose supplementation can alleviate exercise intolerance in these patients. METHODS: This is a case-control study with 4 patients with GYG1 deficiency and 4 healthy controls. Patients performed 1 hour of cycling at 50% of their maximal workload capacity, while controls cycled at the same absolute workloads as patients. Heart rate was measured continuously, and production and utilization of fat and glucose was assessed by stable isotope technique...
November 15, 2017: Neurology
https://www.readbyqxmd.com/read/29141439/double-cross-polarization-for-the-indirect-detection-of-nitrogen-14-nuclei-in-magic-angle-spinning-nmr-spectroscopy
#19
Diego Carnevale, Xiao Ji, Geoffrey Bodenhausen
Nitrogen-14 NMR spectra at fast magic-angle spinning rates can be acquired indirectly by means of two-dimensional techniques based on double cross polarization transfer (1)H → (14)N →(1)H. Experimental evidence is given for polycrystalline samples of glycine, l-histidine, and the dipeptide Ala-Gly. Either one-bond or long-range correlations can be favored by choosing the length of the cross polarization contact pulses. Longer contact pulses allow the detection of unprotonated nitrogen sites. In contrast to earlier methods that exploited second-order quadrupolar/dipolar cross-terms, cross polarization operates in the manner of the method of Hartmann and Hahn, even for (14)N quadrupolar couplings up to 4 MHz...
November 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29140295/quantification-of-cardiovascular-disease-biomarkers-in-human-platelets-by-targeted-mass-spectrometry
#20
Sebastian Malchow, Christina Loosse, Albert Sickmann, Christin Lorenz
Platelets are known to be key players in thrombosis and hemostasis, contributing to the genesis and progression of cardiovascular diseases. Due to their pivotal role in human physiology and pathology, platelet function is regulated tightly by numerous factors which have either stimulatory or inhibitory effects. A variety of factors, e.g., collagen, fibrinogen, ADP, vWF, thrombin, and thromboxane promote platelet adhesion and aggregation by utilizing multiple intracellular signal cascades. To quantify platelet proteins for this work, a targeted proteomics workflow was applied...
November 15, 2017: Proteomes
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