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https://www.readbyqxmd.com/read/28092855/lc-ms-ms-determination-of-d-mannose-in-human-serum-as-a-potential-cancer-biomarker
#1
Lyndsey White, Jing Ma, Su Liang, Beatriz Sanchez-Espiridion, Dong Liang
Several metabolites in human serum have been identified as potential cancer biomarkers for early detection. This study focuses on the LC-MS/MS method development and validation of d-mannose in human serum. Surrogate blank serum, coupled with stable isotope d-mannose-(13)C6, as internal standard, was used for generating standard curves ranging from 1 to 50μg/mL. Separation was achieved by an Agilent 1200 series HPLC equipped with a SUPELCOGELTM Pb, 6% Crosslinked column with HPLC water as a mobile phase at flow rate of 0...
December 28, 2016: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28092812/%C3%AE-14-co2-from-dark-respiration-in-plants-and-its-impact-on-the-estimation-of-atmospheric-fossil-fuel-co2
#2
Xiaohu Xiong, Weijian Zhou, Peng Cheng, Shugang Wu, Zhenchuan Niu, Hua Du, Xuefeng Lu, Yunchong Fu, George S Burr
Radiocarbon ((14)C) has been widely used for quantification of fossil fuel CO2 (CO2ff) in the atmosphere and for ecosystem source partitioning studies. The strength of the technique lies in the intrinsic differences between the (14)C signature of fossil fuels and other sources. In past studies, the (14)C content of CO2 derived from plants has been equated with the (14)C content of the atmosphere. Carbon isotopic fractionation mechanisms vary among plants however, and experimental study on fractionation associated with dark respiration is lacking...
January 13, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28092743/stable-isotope-composition-of-mercury-forms-in-flue-gases-from-a-typical-coal-fired-power-plant-inner-mongolia-northern-china
#3
Shunlin Tang, Chaohui Feng, Xinbin Feng, Jianming Zhu, Ruoyu Sun, Huipeng Fan, Lina Wang, Ruiyang Li, Tonghua Mao, Ting Zhou
Mercury forms emitted from coal combustion via air pollution control devices are speculated to carry different Hg isotope signatures. Yet, their Hg isotope composition is still not reported. Here, we present the first onsite Hg isotope data for gaseous elemental Hg (GEM) and gaseous oxidized Hg (GOM) of flue gases from a typical lignite-fired power plant (CFPP). Significant mass dependent fractionation (MDF) and insignificant mass independent fractionation (MIF) are observed between feed coal and coal combustion products...
January 11, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28092047/analysis-of-the-global-changes-in-sh2-binding-properties-using-mass-spectrometry-supported-by-quantitative-stable-isotope-labeling-by-amino-acids-in-cell-culture-silac-technique
#4
Radoslaw M Sobota
Quantitative mass spectrometry (MS)-based proteomics enables fast and reliable analysis of protein complexes. Its robustness and sensitivity effectively substitute traditional antibody-based approaches. Here, we describe the combination of mass spectrometry and Stable Isotope Labeling by Amino acids in Cell culture (SILAC) in characterization of the SH2 domain binding capacity.
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28092038/nmr-chemical-shift-mapping-of-sh2-peptide-interactions
#5
Marissa A McKercher, Deborah S Wuttke
Heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) experiments offer a rapid and high resolution approach to gaining binding and conformational insights into a protein-peptide interaction. By tracking (1)H and (15)N chemical shift changes over the course of a peptide titration into isotopically labeled protein, amide NH pairs of amino acids whose chemical environment changes upon peptide binding can be identified. When mapped onto a structure of the protein, this approach can identify the peptide-binding interface or regions undergoing conformation changes within a protein upon ligand binding...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28091930/non-equilibrium-molecular-dynamics-simulations-of-the-transient-ludwig-soret-effect-in-a-binary-lennard-jones-spline-mixture
#6
Bjørn Hafskjold
A binary isotope mixture of Lennard-Jones/spline particles at equilibrium was perturbed by a sudden change in the system's boundary temperatures. The system's response was determined by non-equilibrium molecular dynamics (NEMD). Three transient processes were studied: 1) The propagation of a pressure (shock) wave, 2) heat diffusivity and conduction, and 3) thermal diffusion (the Ludwig-Soret effect). These three processes occur at different time scales, which makes it possible to separate them in one single NEMD run...
January 2017: European Physical Journal. E, Soft Matter
https://www.readbyqxmd.com/read/28091753/vtst-mt-studies-of-the-catalytic-mechanism-of-c-h-activation-by-transition-metal-complexes-with-cu2-%C3%AE-o2-fe2-%C3%AE-o2-and-fe-iv-o-cores-based-on-dft-potential-energy-surfaces
#7
REVIEW
Yongho Kim, Binh Khanh Mai, Sumin Park
High-valent Cu and Fe species, which are generated from dioxygen activation in metalloenzymes, carry out the functionalization of strong C-H bonds. Understanding the atomic details of the catalytic mechanism has long been one of the main objectives of bioinorganic chemistry. Large H/D kinetic isotope effects (KIEs) were observed in the C-H activation by high-valent non-heme Cu or Fe complexes in enzymes and their synthetic models. The H/D KIE depends significantly on the transition state properties, such as structure, energies, frequencies, and shape of the potential energy surface, when the tunneling effect is large...
January 16, 2017: Journal of Biological Inorganic Chemistry: JBIC
https://www.readbyqxmd.com/read/28091714/comparison-of-potential-higher-order-reference-methods-for-total-haemoglobin-quantification-an-interlaboratory-study
#8
Claudia Frank, Christine Brauckmann, Marie Palos, Cristian G Arsene, Joerg Neukammer, Maria Estela Del Castillo Busto, Sabine Zakel, Claudia Swart, Bernd Güttler, Rainer Stosch
The total haemoglobin (Hb) concentration in blood is one of the most frequently measured analytes in clinical medicine because of its significance for evaluating the health state of a human. The spectrophotometric cyanmethaemoglobin (HiCN) method is the internationally accepted conventional reference method to determine this biomarker. It is frequently used in clinical routine diagnostics but is not traceable to the International System of Units and thus does not meet highest metrological demands. A further critical issue is the toxicity of the necessary potassium cyanide...
January 14, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28091646/molecular-hydrogen-production-from-amorphous-solid-water-during-low-energy-electron-irradiation
#9
Kamel A K Gadallah, Demian Marchione, Sven P K Koehler, Martin R S McCoustra
This work investigates the production of molecular hydrogen isotopologues (H2, HD, and D2) during low energy electron irradiation of layered and isotopically labelled thin films of amorphous solid water (ASW) in ultrahigh vacuum. Experimentally, the production of these molecules with both irradiation time and incident electron energy in the range 400 to 500 eV is reported as a function of the depth of a buried D2O layer in an H2O film. H2 is produced consistently in all measurements, reflecting the H2O component of the film, though it does exhibit a modest reduction in intensity at the time corresponding to product escape from the buried D2O layer...
January 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28091618/chemical-isotope-labeling-lc-ms-for-monitoring-disease-progression-and-treatment-in-animal-models-plasma-metabolomics-study-of-osteoarthritis-rat-model
#10
Deying Chen, Xiaoling Su, Nan Wang, Yunong Li, Hua Yin, Liang Li, Lanjuan Li
We report a chemical isotope labeling (CIL) liquid chromatography mass spectrometry (LC-MS) method generally applicable for tracking metabolomic changes from samples collected in an animal model for studying disease development and treatment. A rat model of surgically induced osteoarthritis (OA) was used as an example to illustrate the workflow and technical performance. Experimental duplicate analyses of 234 plasma samples were carried out using dansylation labeling LC-MS targeting the amine/phenol submetabolome...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28091604/polyglucose-nanoparticles-with-renal-elimination-and-macrophage-avidity-facilitate-pet-imaging-in-ischaemic-heart-disease
#11
Edmund J Keliher, Yu-Xiang Ye, Gregory R Wojtkiewicz, Aaron D Aguirre, Benoit Tricot, Max L Senders, Hannah Groenen, Francois Fay, Carlos Perez-Medina, Claudia Calcagno, Giuseppe Carlucci, Thomas Reiner, Yuan Sun, Gabriel Courties, Yoshiko Iwamoto, Hye-Yeong Kim, Cuihua Wang, John W Chen, Filip K Swirski, Hsiao-Ying Wey, Jacob Hooker, Zahi A Fayad, Willem J M Mulder, Ralph Weissleder, Matthias Nahrendorf
Tissue macrophage numbers vary during health versus disease. Abundant inflammatory macrophages destruct tissues, leading to atherosclerosis, myocardial infarction and heart failure. Emerging therapeutic options create interest in monitoring macrophages in patients. Here we describe positron emission tomography (PET) imaging with (18)F-Macroflor, a modified polyglucose nanoparticle with high avidity for macrophages. Due to its small size, Macroflor is excreted renally, a prerequisite for imaging with the isotope flourine-18...
January 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28091595/geological-support-for-the-umbrella-effect-as-a-link-between-geomagnetic-field-and-climate
#12
Ikuko Kitaba, Masayuki Hyodo, Takeshi Nakagawa, Shigehiro Katoh, David L Dettman, Hiroshi Sato
The weakening of the geomagnetic field causes an increase in galactic cosmic ray (GCR) flux. Some researchers argue that enhanced GCR flux might lead to a climatic cooling by increasing low cloud formation, which enhances albedo (umbrella effect). Recent studies have reported geological evidence for a link between weakened geomagnetic field and climatic cooling. However, more work is needed on the mechanism of this link, including whether the umbrella effect is playing a central role. In this research, we present new geological evidence that GCR flux change had a greater impact on continental climate than on oceanic climate...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28091552/dual-sources-of-water-overprinting-on-the-low-zircon-%C3%AE-18-o-metamorphic-country-rocks-disequilibrium-constrained-through-inverse-modelling-of-partial-reequilibration
#13
Chun-Sheng Wei, Zi-Fu Zhao
Since water is only composed of oxygen and hydrogen, δ(18)O and δ(2)H values are thus utilized to trace the origin of water(s) and quantify the water-rock interactions. While Triassic high pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks across the Dabie-Sulu orogen in central-eastern China have been well documented, postcollisional magmatism driven hydrothermal systems are little known. Here we show that two sources of externally derived water interactions were revealed by oxygen isotopes for the gneissic country rocks intruded by the early Cretaceous postcollisional granitoids...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28091361/responses-of-plasma-glucose-metabolism-to-exogenous-insulin-infusion-in-sheep-fed-forage-herb-plantain-and-exposed-to-heat
#14
M Al-Mamun, K Shibuya, M Kajita, Y Tamura, H Sano
The use of herbal plants as traditional medicines has a century long history. Plantain (Plantago lanceolata L.) is a perennial herb containing bioactive components with free radical scavenging activities. An isotope dilution technique using [U-13C]glucose was conducted to determine the effect of plantain on the responses of plasma glucose metabolism to exogenous insulin infusion in sheep. Six crossbred sheep (three wethers and three ewes; mean initial BW=40±2 kg) were fed either a mixed hay of orchardgrass (Dactylis glomerata) and reed canarygrass (Phalaris arundinacea) (MH-diet) or mixed hay and fresh plantain (1 : 1 ratio, dry matter basis, PL-diet) and exposed to a thermoneutral (TN, 20°C; 70% relative humidity (RH)) environment or a heat exposure (HE, 30°C; 70% RH) for 5 days using a crossover design for two 23-day periods...
January 16, 2017: Animal: An International Journal of Animal Bioscience
https://www.readbyqxmd.com/read/28090435/-13-c-metabolomics-nmr-and-iroa-for-unknown-identification
#15
Chaevien S Clendinen, Gregory S Stupp, Bing Wang, Timothy J Garrett, Arthur S Edison
ABSTRACT BACKGROUND: Isotopic Ratio Outlier Analysis (IROA) is an untargeted metabolomics method that uses stable isotopic labeling and LC-HRMS for identification and relative quantification of metabolites in a biological sample under varying experimental conditions. OBJECTIVE: We demonstrate a method using high-sensitivity (13)C NMR to identify an unknown metabolite isolated from fractionated material from an IROA LC-HRMS experiment. METHODS: IROA samples from the nematode Caenorhabditis elegans were fractionated using LC-HRMS using 5 repeated injections and collecting 30 sec fractions...
August 2016: Current Metabolomics
https://www.readbyqxmd.com/read/28089618/24-hour-protein-arginine-and-citrulline-metabolism-in-fed-critically-ill-children-a-stable-isotope-tracer-study
#16
Carlijn T I de Betue, Xiomara C Garcia Casal, Dick A van Waardenburg, Stephen M Schexnayder, Koen F M Joosten, Nicolaas E P Deutz, Marielle P K J Engelen
BACKGROUND & AIMS: The reference method to study protein and arginine metabolism in critically ill children is measuring plasma amino acid appearances with stable isotopes during a short (4-8 h) time period and extrapolate results to 24-h. However, 24-h measurements may be variable due to critical illness related factors and a circadian rhythm could be present. Since only short duration stable isotope studies in critically ill children have been conducted before, the aim of this study was to investigate 24-h appearance of specific amino acids representing protein and arginine metabolism, with stable isotope techniques in continuously fed critically ill children...
January 4, 2017: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
https://www.readbyqxmd.com/read/28089533/bias-and-association-of-sediment-organic-matter-source-apportionment-indicators-a-case-study-in-a-eutrophic-lake-chaohu-china
#17
Fu-Liu Xu, Chen Yang, Wei He, Qi-Shuang He, Yi-Long Li, Lei Kang, Wen-Xiu Liu, Yong-Qiang Xiong, Baoshan Xing
The sources of sediment organic matter (SOM) could be explained by various indicators. To test their biases and associations, the present study determined multiple indicators for SOM source apportionment, including elemental analysis (carbon and nitrogen, and their stable isotope δ(13)C and δ(15)N), n-alkanes compositions as well as derivative indicators (e.g., terrigenous to aquatic ratio), and carbon isotopes of n-alkane in Lake Chaohu, a eutrophic lake. The spatial variation of anthropogenic effects could be revealed by SOM elemental variations...
January 12, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28089399/a-mass-balance-model-to-estimate-the-rate-of-composting-methane-oxidation-and-anaerobic-digestion-in-soil-covers-and-shallow-waste-layers
#18
Reza Rafiee, Lizanne Obersky, Sihuang Xie, William P Clarke
Although CH4 oxidation in landfill soil covers is widely studied, the extent of composting and CH4 oxidation in underlying waste layers has been speculated but not measured. The objective of this study was to develop and validate a mass balance model to estimate the simultaneous rates of anaerobic digestion (rAD), CH4 oxidation (rOX) and composting (rCOM) in environments where O2 penetration is variable and zones of aerobic and anaerobic activity are intermingled. The modelled domain could include, as an example, a soil cover and the underlying shallow waste to a nominated depth...
January 12, 2017: Waste Management
https://www.readbyqxmd.com/read/28088859/determination-of-the-geographical-origin-of-all-commercial-hake-species-by-stable-isotope-ratio-sir-analysis
#19
Mónica Carrera, José M Gallardo
The determination of the geographical origin of food products is relevant to comply with the legal regulations of traceability, avoid food fraud and guarantee the food quality and safety to the consumers. For these reasons, Stable Isotope Ratio (SIR) analysis using an isotope ratio mass spectrometry (IRMS) instrument is one of the most useful technique for evaluating food traceability and authenticity. The present study was aimed to determine for the first time, the geographical origin for all commercial fish species belonging to the Merlucciidae family using SIR analysis of carbon (δ13C) and nitrogen (δ15N)...
January 15, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28088853/the-formation-of-ti-h-species-at-interface-is-lethal-to-the-efficiency-of-tio2-based-dye-sensitized-devices
#20
Yan Yan, Weidong Shi, Zhen Yuan, Shenggui He, Dongmei Li, Qingbo Meng, Hongwei Ji, Chuncheng Chen, Wanhong Ma, Jincai Zhao
TiO2-based dye-sensitization cycle is one of the basic strategies for the development of solar energy applications. Although the power conversion efficiency (PCE) of dye-sensitized devices has been improved through constant attempts, the intrinsically fatal factor that leads to the complete failure of the PCE of TiO2-mediated dye-sensitized devices has not yet been determined. Here, by using isotopically labeled MAS-1H NMR, ATR-FTIR spectroscopy (separate H/D and 48Ti/49Ti experiments) and ESR, we revealed that the accumulative formation of Ti-H species on the TiO2 surface is the intrinsic cause of the PCE failure of TiO2-based dye-sensitization devices...
January 15, 2017: Journal of the American Chemical Society
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