keyword
MENU ▼
Read by QxMD icon Read
search

Isotope tracer

keyword
https://www.readbyqxmd.com/read/29134098/progressive-ontogenetic-niche-shift-over-the-prolonged-immaturity-period-of-wandering-albatrosses
#1
Alice Carravieri, Henri Weimerskirch, Paco Bustamante, Yves Cherel
Very little is known about trophic ontogenetic changes over the prolonged immaturity period of long-lived, wide-ranging seabirds. By using blood and feather trophic tracers (δ(13)C and δ(15)N, and mercury, Hg), we studied age-related changes in feeding ecology during the immature phase of wandering albatrosses Diomedea exulans when they gradually change from a pure oceanic life to visits to their future breeding grounds. Immatures fed in subtropical waters at high trophic positions during moult. Between- and within-individual variations in isotopic niche were very high, irrespective of age, highlighting wide-ranging exploratory behaviours...
October 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/29131928/n-and-o-isotope-%C3%AE-15-n-%C3%AE-%C3%AE-15-n-%C3%AE-%C3%AE-18-o-%C3%AE-17-o-analyses-of-dissolved-no3-and-no2-by-the-cd-azide-reduction-method-and-n2-o-laser-spectrometry
#2
Leonard I Wassenaar, Cedric Douence, Mark Altabet, Pradeep Aggarwal
RATIONALE: The nitrogen and oxygen (δ(15) N, δ(18) O, δ(17) O) isotopic compositions of NO3(-) and NO2(-) are important tracers of nutrient dynamics in soil, rain, groundwater and the oceans. The Cd-azide method was used to convert NO3 or NO2 to N2 O for N and triple-O isotopic analyses by N2 O-laser spectrometry. A protocol for laser-based headspace isotope analyses was compared with isotope-ratio mass spectrometry. Lasers provide the ability to directly measure (17) O anomalies which can help discern atmospheric N sources...
November 13, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/29130969/mechanistic-links-underlying-the-impact-of-c-reactive-protein-on-muscle-mass-in-elderly
#3
Britta Wåhlin-Larsson, Daniel J Wilkinson, Emelie Strandberg, Adrian Hosford-Donovan, Philip J Atherton, Fawzi Kadi
BACKGROUND/AIMS: Mechanisms underlying the relationship between systemic inflammation and age-related decline in muscle mass are poorly defined. The purpose of this work was to investigate the relationship between the systemic inflammatory marker CRP and muscle mass in elderly and to identify mechanisms by which CRP mediates its effects on skeletal muscle, in-vitro. METHODS: Muscle mass and serum CRP level were determined in a cohort of 118 older women (67±1.7 years)...
November 9, 2017: Cellular Physiology and Biochemistry
https://www.readbyqxmd.com/read/29129455/plasma-palmitoyl-carnitine-ac16-0-is-a-marker-of-increased-postprandial-nonesterified-incomplete-fatty-acid-oxidation-rate-in-individuals-with-type-2-diabetes
#4
Fatima-Zahra Bouchouirab, Mélanie Fortin, Christophe Noll, Jean Dubé, André C Carpentier
OBJECTIVES: Enhanced mitochondrial fatty acid utilization is known to increase radical oxidative stress and induce insulin resistance. An increased level of plasma acylcarnitine (AC) has been proposed to indicate mitochondrial energy substrate overload, a possible mechanism leading to insulin resistance. The aim of our study was to determine fasting and postprandial plasma acetyl-carnitine (AC2:0), palmitoyl-carnitine (AC16:0), oleoyl-carnitine (AC18:1) and linoleoyl-carnitine (AC18:2) levels and their relationships with plasma nonesterified fatty acid appearance and oxidation rates and insulin sensitivity in participants with type 2 diabetes and normoglycemic offspring of 2 parents with type 2 diabetes (FH+) compared to healthy participants without family histories of type 2 diabetes (FH-)...
November 9, 2017: Canadian Journal of Diabetes
https://www.readbyqxmd.com/read/29123536/response-of-summer-maize-photosynthate-accumulation-and-distribution-to-shading-stress-assessed-by-using-13-co2-stable-isotope-tracer-in-the-field
#5
Jia Gao, Bin Zhao, Shuting Dong, Peng Liu, Baizhao Ren, Jiwang Zhang
Maize is one of the most important crops globally that provides food, feed, and bioenergy. However, shading stress threatens maize production. In this study, we investigated the effects of shading on photosynthate accumulation and distribution of summer maize in the field. Zhengdan958 (ZD958) and Denghai 605 (DH605) were used as experimental materials in a field experiment running from 2013 to 2015. Shading treatments were applied over different growth stages: from the tassel stage (VT) to physiological maturity (R6) (S1), from the six-leaf stage (V6) to VT (S2), and from emergence stage (VE) to R6 (S3)...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/29116768/greenhouse-gas-dynamics-in-a-salt-wedge-estuary-revealed-by-high-resolution-cavity-ring-down-spectroscopy-observations
#6
Douglas R Tait, Damien Troy Maher, Wei Wen Wong, Isaac R Santos, Mahmood Sadat-Noori, Ceylena Holloway, Perran Louis Miall Cook
Estuaries are an important source of greenhouse gases to the atmosphere, but uncertainties remain in the flux rates and production pathways of greenhouse gases in these dynamic systems. This study performs simultaneous high resolution measurements of the three major greenhouse gases (carbon dioxide, methane, and nitrous oxide) as well as carbon stable isotope ratios of carbon dioxide and methane, above and below the pycnocline along a salt wedge estuary (Yarra River estuary, Australia). We identified distinct zones of elevated greenhouse gas concentrations...
November 8, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29107780/cd-isotope-fractionation-during-sulfide-mineral-weathering-in-the-fule-zn-pb-cd-deposit-yunnan-province-southwest-china
#7
Chuanwei Zhu, Hanjie Wen, Yuxu Zhang, Runsheng Yin, Christophe Cloquet
Zinc (Zn)-Lead (Pb) deposits are generally rich in cadmium (Cd), and the weathering of sulfide minerals in such deposits results in large releases of Cd into the environment. From an environmental and public health standpoint, understanding Cd sources and cycling is critical to identifying potential hazards to humans. In this study, the Cd isotope compositions (expressed as δ(114/110)Cd) of secondary minerals such as anglesite (-0.57±0.03‰; 2S.D.), granular smithsonite (0.04±0.14‰; 2S.D.), layered smithsonite (0...
November 3, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29107283/acute-activation-of-glp-1-expressing-neurons-promotes-glucose-homeostasis-and-insulin-sensitivity
#8
Xuemei Shi, Shaji Chacko, Feng Li, Depei Li, Douglas Burrin, Lawrence Chan, Xinfu Guan
OBJECTIVE: Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. METHODS: We generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected excitatory hM3Dq-mCherry AAV into their brainstem NTS...
November 2017: Molecular Metabolism
https://www.readbyqxmd.com/read/29106312/nitrogen-concentrations-and-isotopic-compositions-of-seafloor-altered-terrestrial-basaltic-glass-implications-for-astrobiology
#9
G E Bebout, N R Banerjee, M R M Izawa, K Kobayashi, K Lazzeri, L A Ranieri, E Nakamura
Observed enrichments of N (and the δ(15)N of this N) in volcanic glasses altered on Earth's modern and ancient seafloor are relevant in considerations of modern global N subduction fluxes and ancient life on Earth, and similarly altered glasses on Mars and other extraterrestrial bodies could serve as valuable tracers of biogeochemical processes. Palagonitized glasses and whole-rock samples of volcanic rocks on the modern seafloor (ODP Site 1256D) contain 3-18 ppm N with δ(15)Nair values of up to +4.5‰...
November 6, 2017: Astrobiology
https://www.readbyqxmd.com/read/29096152/analysis-of-air-mass-trajectories-to-explain-observed-variability-of-tritium-in-precipitation-at-the-southern-sierra-critical-zone-observatory-california-usa
#10
Ate Visser, Melissa Thaw, Brad Esser
Understanding the behavior of tritium, a radioactive isotope of hydrogen, in the environment is important to evaluate the exposure risk of anthropogenic releases, and for its application as a tracer in hydrology and oceanography. To understand and predict the variability of tritium in precipitation, HYSPLIT air mass trajectories were analyzed for 16 aggregate precipitation samples collected over a 2 year period at irregular intervals at a research site located at 2000 m elevation in the southern Sierra Nevada (California, USA)...
October 30, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/29078954/elucidation-of-oxidation-and-degradation-products-of-oxygen-containing-fuel-components-by-combined-use-of-a-stable-isotopic-tracer-and-mass-spectrometry
#11
Marcella Frauscher, Charlotte Besser, Günter Allmaier, Nicole Dörr
In order to reveal the degradation products of oxygen-containing fuel components, in particular fatty acid methyl esters, a novel approach was developed to characterize the oxidation behaviour. Combination of artificial alteration under pressurized oxygen atmosphere, a stable isotopic tracer, and gas chromatography electron impact mass spectrometry (GC-EI-MS) was used to obtain detailed information on the formation of oxidation products of (9Z), (12Z)-octadecadienoic acid methyl ester (C18:2 ME). Thereby, biodiesel simulating model compound C18:2 ME was oxidized in a rotating pressurized vessel standardized for lubricant oxidation tests (RPVOT), i...
November 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29078310/methyl-compound-use-and-slow-growth-characterize-microbial-life-in-2-km-deep-subseafloor-coal-and-shale-beds
#12
Elizabeth Trembath-Reichert, Yuki Morono, Akira Ijiri, Tatsuhiko Hoshino, Katherine S Dawson, Fumio Inagaki, Victoria J Orphan
The past decade of scientific ocean drilling has revealed seemingly ubiquitous, slow-growing microbial life within a range of deep biosphere habitats. Integrated Ocean Drilling Program Expedition 337 expanded these studies by successfully coring Miocene-aged coal beds 2 km below the seafloor hypothesized to be "hot spots" for microbial life. To characterize the activity of coal-associated microorganisms from this site, a series of stable isotope probing (SIP) experiments were conducted using intact pieces of coal and overlying shale incubated at in situ temperatures (45 °C)...
October 31, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29073064/human-shmt-inhibitors-reveal-defective-glycine-import-as-a-targetable-metabolic-vulnerability-of-diffuse-large-b-cell-lymphoma
#13
Gregory S Ducker, Jonathan M Ghergurovich, Nello Mainolfi, Vipin Suri, Stephanie K Jeong, Sophia Hsin-Jung Li, Adam Friedman, Mark G Manfredi, Zemer Gitai, Hahn Kim, Joshua D Rabinowitz
The enzyme serine hydroxymethyltransferse (SHMT) converts serine into glycine and a tetrahydrofolate-bound one-carbon unit. Folate one-carbon units support purine and thymidine synthesis, and thus cell growth. Mammals have both cytosolic SHMT1 and mitochondrial SHMT2, with the mitochondrial isozyme strongly up-regulated in cancer. Here we show genetically that dual SHMT1/2 knockout blocks HCT-116 colon cancer tumor xenograft formation. Building from a pyrazolopyran scaffold that inhibits plant SHMT, we identify small-molecule dual inhibitors of human SHMT1/2 (biochemical IC50 ∼ 10 nM)...
October 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29055827/using-stable-isotope-labeling-to-study-the-nitrogen-metabolism-in-anabaena-flos-aquae-growth-and-anatoxin-biosynthesis
#14
Zong-Yao Qian, Jian Ma, Chun-Lei Sun, Zhi-Gang Li, Qi-Ming Xian, Ting-Ting Gong, Bin Xu
Freshwater resources are under stress around the world due to rapid urbanization and excessive water consumption. Cyanobacterial blooms have occurred frequently in surface waters, which produced toxic secondary metabolites causing a potential harm to aquatic ecosystems and humans. In this study, the relationship between different types of nitrogen source and the algal growth of Anabaena flos-aquae, which was isolated from Dianchi Lake in southern China, was investigated. Experiments were accomplished by using four types of isotope tracers including (15)N-ammonium chloride, (15)N-sodium nitrate, (15)N-urea, (15)N-l-alanine in culture medium to characterize the biosynthesis of (15)N-anatoxin-a (ATX-A), which is a major algal toxin from A...
October 6, 2017: Water Research
https://www.readbyqxmd.com/read/29054640/apportioning-source-of-erosion-induced-organic-matter-in-the-hilly-gully-region-of-loess-plateau-in-china-insight-from-lipid-biomarker-and-isotopic-signature-analysis
#15
Chun Liu, Zhongwu Li, Xiaofeng Chang, Xiaodong Nie, Lin Liu, Haibing Xiao, Danyang Wang, Hao Peng, Guangming Zeng
Understanding the dynamics of organic matter (OM) at global and local scales is one of the challenges in the environmental sciences and i.e. terrestrial biogeochemistry. The accurate identification of OM is an essential element to achieve this goal. In our study, a novel application for quantitatively apportioning sources of eroded sedimentary OM from an eco-geomorphologic perspective was shown successfully via a coupled molecular n-alkane biomarkers and stable isotopic signatures ((13)C and (15)N) along with elemental compositions (TOC and TN) using a Bayesian mixing model (SIAR)...
October 17, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29054406/a-novel-puromycin-decorporation-method-to-quantify-skeletal-muscle-protein-breakdown-a-proof-of-concept-study
#16
Hannah Crossland, Kenneth Smith, Philip J Atherton, Daniel J Wilkinson
The precise roles that the major proteolytic pathways play in the regulation of skeletal muscle mass remain incompletely understood, in part due to technical limitations associated with current techniques used to quantify muscle protein breakdown (MPB). We aimed to develop a method to assess MPB in cells, based on loss of puromycin labelling of translated polypeptide chains. Following an initial 24 h incubation period with puromycin (1 μM), loss of puromycin labelling from murine C2C12 myotubes was assessed over 48 h, both in the presence or absence of protein synthesis inhibitor cycloheximide (CHX)...
October 17, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29039474/evaluation-of-a-radiocobalt-labelled-affibody-molecule-for-imaging-of-human-epidermal-growth-factor-receptor-3-expression
#17
Maria Rosestedt, Ken G Andersson, Bogdan Mitran, Sara S Rinne, Vladimir Tolmachev, John Löfblom, Anna Orlova, Stefan Ståhl
The human epidermal growth factor receptor 3 (HER3) is involved in the development of cancer resistance towards tyrosine kinase-targeted therapies. Several HER3‑targeting therapeutics are currently under clinical evaluation. Non-invasive imaging of HER3 expression could improve patient management. Affibody molecules are small engineered scaffold proteins demonstrating superior properties as targeting probes for molecular imaging compared with monoclonal antibodies. Feasibility of in vivo HER3 imaging using affibody molecules has been previously demonstrated...
October 11, 2017: International Journal of Oncology
https://www.readbyqxmd.com/read/29039106/improved-ultrafiltration-method-to-measure-drug-release-from-nanomedicines-utilizing-a-stable-isotope-tracer
#18
Sarah L Skoczen, Stephan T Stern
An important step in the early development of a nanomedicine formulation is the evaluation of stability and drug release in biological matrices. Additionally, the measurement of encapsulated and unencapsulated nanomedicine drug fractions is important for the determination of bioequivalence (pharmacokinetic equivalence) of generic nanomedicines. Unfortunately, current methods to measure drug release in plasma are limited, and all have fundamental disadvantages including non-equilibrium conditions and process-induced artifacts...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/29035268/trace-element-and-isotope-deposition-across-the-air-sea-interface-progress-and-research-needs
#19
REVIEW
A R Baker, W M Landing, E Bucciarelli, M Cheize, S Fietz, C T Hayes, D Kadko, P L Morton, N Rogan, G Sarthou, R U Shelley, Z Shi, A Shiller, M M P van Hulten
The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted...
November 28, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/29035267/coastal-ocean-and-shelf-sea-biogeochemical-cycling-of-trace-elements-and-isotopes-lessons-learned-from-geotraces
#20
REVIEW
Matthew A Charette, Phoebe J Lam, Maeve C Lohan, Eun Young Kwon, Vanessa Hatje, Catherine Jeandel, Alan M Shiller, Gregory A Cutter, Alex Thomas, Philip W Boyd, William B Homoky, Angela Milne, Helmuth Thomas, Per S Andersson, Don Porcelli, Takahiro Tanaka, Walter Geibert, Frank Dehairs, Jordi Garcia-Orellana
Continental shelves and shelf seas play a central role in the global carbon cycle. However, their importance with respect to trace element and isotope (TEI) inputs to ocean basins is less well understood. Here, we present major findings on shelf TEI biogeochemistry from the GEOTRACES programme as well as a proof of concept for a new method to estimate shelf TEI fluxes. The case studies focus on advances in our understanding of TEI cycling in the Arctic, transformations within a major river estuary (Amazon), shelf sediment micronutrient fluxes and basin-scale estimates of submarine groundwater discharge...
November 28, 2016: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
keyword
keyword
41874
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"