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https://www.readbyqxmd.com/read/28938478/roux-en-y-gastric-bypass-surgery-has-unique-effects-on-postprandial-fgf21-but-not-fgf19-secretion
#1
Lydia-Ann L S Harris, Gordon I Smith, Bettina Mittendorfer, J Christopher Eagon, Adewole L Okunade, Bruce W Patterson, Samuel Klein
Context: Fibroblast growth factors (FGF) 19 and FGF21 are secreted by the intestine and liver in response to macronutrient intake. Intestinal resection and reconstruction via bariatric surgery may alter their regulation. Objective: We tested the hypothesis that weight loss induced by Roux-en-Y gastric bypass (RYGB) surgery, but not matched weight loss induced by laparoscopic adjustable gastric banding (LAGB), increases postprandial plasma FGF19 and FGF21 concentrations...
August 17, 2017: Journal of Clinical Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28938217/deriving-nitrogen-critical-levels-and-loads-based-on-the-responses-of-acidophytic-lichen-communities-on-boreal-urban-pinus-sylvestris-trunks
#2
Sirkku Manninen
The deposition of reactive nitrogen (N) compounds currently predominates over sulphur (S) deposition in most of the cities in Europe and North America. Acidophytic lichens growing on tree trunks are known to be sensitive to both N and S deposition. Given that tree species and climatic factors affect the composition of epiphytic lichen communities and modify lichen responses to air pollution, this study focused on the impact of urban air pollution on acidophytes growing on boreal conifer trunks. The study was performed in the Helsinki metropolitan area, southern Finland, where annual mean nitrogen dioxide (NO2) concentrations range from 4-5μgm(-3) to >50μgm(-3)...
September 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28938212/the-problem-of-identifying-arsenic-anomalies-in-the-basin-of-sahand-dam-through-risk-based-soft-modelling
#3
Ata Allah Nadiri, Fariba Sadeghi Aghdam, Rahman Khatibi, Asghar Asghari Moghaddam
An investigation is undertaken to identify arsenic anomalies at the complex of Sahand dam, East Azerbaijan, northwest Iran. The complex acts as a system, in which the impounding reservoir catalyses system components related to Origin-Source-Pathways-Receptor-Consequence (OSPRC) viewed as a risk system. This 'conceptual framework' overlays a 'perceptual model' of the physical system, in which arsenic with geogenic origins diffused into the formations through extensive fractures swept through the region during the Miocene era...
September 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28938176/genotypic-differences-in-physiological-and-biochemical-responses-to-salinity-stress-in-melon-cucumis-melo-l-plants-prospects-for-selection-of-salt-tolerant-landraces
#4
Behrooz Sarabi, Sahebali Bolandnazar, Nasser Ghaderi, Jaleh Ghashghaie
Melon (Cucumis melo L.) is one of the most important horticultural crops in Iran often cultivated in arid and semiarid regions of the country with salinity problems. The objective of this work was to better understand the mechanisms of physiological and biochemical responses to salinity stress of five Iranian melon landraces "Samsuri", "Kashan", "Khatouni", "Suski-e-Sabz", and "Ghobadlu" from different geographical origins, and "Galia" F1 cultivar. Plants were grown under greenhouse conditions and irrigated with half-strength Hoagland solution containing 0, 30, 60, or 90 mM NaCl for 60 days...
September 13, 2017: Plant Physiology and Biochemistry: PPB
https://www.readbyqxmd.com/read/28938002/regional-endothermy-as-a-trigger-for-gigantism-in-some-extinct-macropredatory-sharks
#5
Humberto G Ferrón
Otodontids include some of the largest macropredatory sharks that ever lived, the most extreme case being Otodus (Megaselachus) megalodon. The reasons underlying their gigantism, distribution patterns and extinction have been classically linked with climatic factors and the evolution, radiation and migrations of cetaceans during the Paleogene. However, most of these previous proposals are based on the idea of otodontids as ectothermic sharks regardless of the ecological, energetic and body size constraints that this implies...
2017: PloS One
https://www.readbyqxmd.com/read/28937751/high-precision-simultaneous-18-o-16-o-13-c-12-c-and-17-o-16-o-analyses-for-%C3%A2%C2%B5g-quantities-of-caco3-by-tunable-infrared-laser-absorption-spectroscopy
#6
Saburo Sakai, Shinichi Matsuda, Toshihide Hikida, Akio Shimono, Barry J McManus, Mark S Zahniser, David D Nelson, David Dettman, Danzhou Yang, Naohiko Ohkouchi
Stable isotope ratios ((18)O/(16)O, (13)C/(12)C and (17)O/(16)O) in carbonates have contributed greatly to understanding of Earth and planetary systems, climates, and history. Current methods for measuring isotopologues of CO2 derived from CaCO3 are primarily gas-source isotope ratio mass spectroscopy (IRMS). However, IRMS has drawbacks, such as mass overlap by multiple CO2 isotopologues and contaminants, the requirement of careful sample purification, and use of major instrumentation needing permanent installation and a high power electrical supply...
September 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28937210/multivariate-analysis-of-2d-1-h-13-c-methyl-nmr-spectra-of-monoclonal-antibody-therapeutics-to-facilitate-assessment-of-higher-order-structure
#7
Luke Arbogast, Frank Delaglio, John E Schiel, John P Marino
Two-dimensional (2D) 1H-13C methyl NMR provides a powerful tool to probe the higher order structure (HOS) of monoclonal antibodies (mAbs), since spectra can readily be acquired on intact mAbs at natural isotopic abundance, and small changes in chemical environment and structure give rise to observable changes in corresponding spectra, which can be interpreted at atomic resolution. This makes it possible to apply 2D NMR spectral fingerprinting approaches directly to drug products in order to systematically characterize structure and excipient effects...
September 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28936805/compound-specific-isotopic-and-congener-specific-analyses-of-polychlorinated-biphenyl-in-the-heat-medium-and-rice-oil-of-the-yusho-incident
#8
Takashi Miyawaki, Mari Sugihara, Shusaku Hirakawa, Tsuguhide Hori, Jumboku Kajiwara, Susumu Katsuki, Chikage Mitoma, Masutaka Furue
Compound-specific isotope analysis (CSIA) can be used to examine the source and transformation processes of organic pollutants in the environment. We performed a carbon stable isotope analysis of polychlorinated biphenyl (PCB) congeners in the PCB heat-transfer medium (heat medium) and the original Kanechlor-400 (KC-400, a commercial brand of PCBs) involved in the Yusho incident. The main purpose is to investigate whether isotope fractionation occurred in the rice oil deodorization process that caused the incident...
September 21, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28936331/double-c-h-bond-activation-of-acetylene-by-atomic-boron-in-forming-aromatic-cyclic-hbc2bh-in-solid-neon
#9
Jiwen Jian, Wei Li, Xuan Wu, Mingfei Zhou
The organo-boron species formed from the reactions of boron atoms with acetylene in solid neon are investigated using matrix isolation infrared spectroscopy with isotopic substitutions as well as quantum chemical calculations. Besides the previously reported single C-H bond activation species, a cyclic-HBC2BH diboron species is formed via double C-H bond activation of acetylene. It is characterized to have a closed-shell singlet ground state with planar D2h symmetry. Bonding analysis indicates that it is a doubly aromatic species involving two delocalized σ electrons and two delocalized π electrons...
June 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28935863/archaean-and-proterozoic-diamond-growth-from-contrasting-styles-of-large-scale-magmatism
#10
Janne M Koornneef, Michael U Gress, Ingrid L Chinn, Hielke A Jelsma, Jeff W Harris, Gareth R Davies
Precise dating of diamond growth is required to understand the interior workings of the early Earth and the deep carbon cycle. Here we report Sm-Nd isotope data from 26 individual garnet inclusions from 26 harzburgitic diamonds from Venetia, South Africa. Garnet inclusions and host diamonds comprise two compositional suites formed under markedly different conditions and define two isochrons, one Archaean (2.95 Ga) and one Proterozoic (1.15 Ga). The Archaean diamond suite formed from relatively cool fluid-dominated metasomatism during rifting of the southern shelf of the Zimbabwe Craton...
September 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28935801/titanium-isotopic-evidence-for-felsic-crust-and-plate-tectonics-3-5-billion-years-ago
#11
Nicolas D Greber, Nicolas Dauphas, Andrey Bekker, Matouš P Ptáček, Ilya N Bindeman, Axel Hofmann
Earth exhibits a dichotomy in elevation and chemical composition between the continents and ocean floor. Reconstructing when this dichotomy arose is important for understanding when plate tectonics started and how the supply of nutrients to the oceans changed through time. We measured the titanium isotopic composition of shales to constrain the chemical composition of the continental crust exposed to weathering and found that shales of all ages have a uniform isotopic composition. This can only be explained if the emerged crust was predominantly felsic (silica-rich) since 3...
September 22, 2017: Science
https://www.readbyqxmd.com/read/28935261/optimization-of-the-solvent-based-dissolution-method-to-sample-volatile-organic-compound-vapors-for-compound-specific-isotope-analysis
#12
Daniel Bouchard, Philipp Wanner, Hong Luo, Patrick W McLoughlin, James K Henderson, Robert J Pirkle, Daniel Hunkeler
The methodology of the solvent-based dissolution method used to sample gas phase volatile organic compounds (VOC) for compound-specific isotope analysis (CSIA) was optimized to lower the method detection limits for TCE and benzene. The sampling methodology previously evaluated by [1] consists in pulling the air through a solvent to dissolve and accumulate the gaseous VOC. After the sampling process, the solvent can then be treated similarly as groundwater samples to perform routine CSIA by diluting an aliquot of the solvent into water to reach the required concentration of the targeted contaminant...
August 24, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28934858/metabolism-nutrition-and-redox-signaling-of-hydroxyproline
#13
Zhenlong Wu, Yongqing Hou, Zhaolai Dai, Chien-An Hu, Guoyao Wu
SIGNIFICANCE: Hydroxyproline is a structurally and physiologically important imino acid in animals. It is provided from diets and endogenous synthesis, and its conversion into glycine is enhances the production of glutathione, DNA, heme, and protein. Furthermore, oxidation of hydroxyproline by hydroxyproline oxidase plays an important role in cell antioxidative reactions, survival, and homeostasis. Understanding the mechanisms whereby hydroxyproline participates in metabolism and cell signaling can improve the nutrition and health of animals and humans...
September 21, 2017: Antioxidants & Redox Signaling
https://www.readbyqxmd.com/read/28934629/lacking-linearity-in-quantitative-stable-isotope-lc-ms-ms-measurement-of-f2-isoprostanes-is-an-irrefutable-indicator-of-analytical-inadequacy
#14
Dimitrios Tsikas, Erik Hanff
In LC-MS/MS-basedquantitative analysis of biological substances such as the F2-isoprostanes including 8-iso-prostaglandin F2α (i.e., 8-iso-PGF2α) use of stable-isotope labelled analogues at matrix-relevant concentrations is indispensable, enables linearity in relevant concentration ranges, and minimizes matrix effects. The quality of the linearity of calibration curves is an indicator of the analytical reliability of the LC-MS/MS method. Poor linearity is a convincing evidence of lacking analytical reliability...
September 8, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28934505/combining-asymmetric-13c-labeling-and-isotopic-filter-edit-noesy-a-novel-strategy-for-rapid-and-logical-rna-resonance-assignment
#15
Regan M LeBlanc, Andrew P Longhini, Stuart F J Le Grice, Bruce A Johnson, Theodore K Dayie
Although ∼98% of the human genomic output is transcribed as non-protein coding RNA, <2% of the protein data bank structures comprise RNA. This huge structural disparity stems from combined difficulties of crystallizing RNA for X-ray crystallography along with extensive chemical shift overlap and broadened linewidths associated with NMR of RNA. While half of the deposited RNA structures in the PDB were solved by NMR methods, the usefulness of NMR is still limited by the high cost of sample preparation and challenges of resonance assignment...
September 19, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28934287/priming-effects-on-labile-and-stable-soil-organic-carbon-decomposition-pulse-dynamics-over-two-years
#16
Xiuwei Zhang, Xiaozeng Han, Wantai Yu, Peng Wang, Weixin Cheng
Soil organic carbon (SOC) is a major component in the global carbon cycle. Yet how input of plant litter may influence the loss of SOC through a phenomenon called priming effect remains highly uncertain. Most published results about the priming effect came from short-term investigations for a few weeks or at the most for a few months in duration. The priming effect has not been studied at the annual time scale. In this study for 815 days, we investigated the priming effect of added maize leaves on SOC decomposition of two soil types and two treatments (bare fallow for 23 years, and adjacent old-field, represent stable and relatively labile SOC, respectively) of SOC stabilities within each soil type, using a natural 13C-isotope method...
2017: PloS One
https://www.readbyqxmd.com/read/28934229/above-and-below-ground-carbohydrate-allocation-differs-between-ash-fraxinus-excelsior-l-and-beech-fagus-sylvatica-l
#17
Ronny Thoms, Michael Köhler, Arthur Gessler, Gerd Gleixner
We investigated soluble carbohydrate transport in trees that differed in their phloem loading strategies in order to better understand the transport of photosynthetic products into the roots and the rhizosphere as this knowledge is needed to better understand the respiratory processes in the rhizosphere. We compared beech, which is suggested to use mainly passive loading of transport sugars along a concentration gradient into the phloem, with ash that uses active loading and polymer trapping of raffinose family oligosaccharides (RFOs)...
2017: PloS One
https://www.readbyqxmd.com/read/28933733/melatonin-decreases-glucose-metabolism-in-prostate-cancer-cells-a-13-c-stable-isotope-resolved-metabolomic-study
#18
David Hevia, Pedro Gonzalez-Menendez, Mario Fernandez-Fernandez, Sergio Cueto, Pablo Rodriguez-Gonzalez, Jose I Garcia-Alonso, Juan C Mayo, Rosa M Sainz
The pineal neuroindole melatonin exerts an exceptional variety of systemic functions. Some of them are exerted through its specific membrane receptors type 1 and type 2 (MT1 and MT2) while others are mediated by receptor-independent mechanisms. A potential transport of melatonin through facilitative glucose transporters (GLUT/SLC2A) was proposed in prostate cancer cells. The prostate cells have a particular metabolism that changes during tumor progression. During the first steps of carcinogenesis, oxidative phosphorylation is reactivated while the switch to the "Warburg effect" only occurs in advanced tumors and in the metastatic stage...
July 26, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28933076/-strategies-of-elucidation-of-biosynthetic-pathways-of-natural-products
#19
Li-Qiu Zou, Xue-Jun Kuang, Chao Sun, Shi-Lin Chen
Elucidation of the biosynthetic pathways of natural products is not only the major goal of herb genomics, but also the solid foundation of synthetic biology of natural products. Here, this paper reviewed recent advance in this field and put forward strategies to elucidate the biosynthetic pathway of natural products. Firstly, a proposed biosynthetic pathway should be set up based on well-known knowledge about chemical reactions and information on the identified compounds, as well as studies with isotope tracer...
November 2016: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
https://www.readbyqxmd.com/read/28932843/applying-neutron-diffraction-with-isotopic-substitution-to-the-structure-and-proton-transport-pathways-in-protic-imidazolium-bis-trifluoromethyl-sulfonyl-imide-ionic-liquids
#20
Adam H Turner, Silvia Imberti, Małgorzata Swadźba-Kwaśny, John D Holbrey
Neutron diffraction with isotopic substitution has been applied to examine the potential for complex-ion formation in protic imidazolium bis{(trifluoromethyl)sulfonyl}imide ionic liquids. Strong cation-anion hydrogen-bonding in the 1 : 1 base : acid ionic liquid results in a high population of anions adopting a cis-conformation and, on adding excess imidazole (2 : 1 base : acid stoichiometry), cation-base and base-base correlations were identified, however, persistent hydrogen-bond associations were not observed...
September 21, 2017: Faraday Discussions
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