Relevant bibliographies by topics / Phosphore – Isotopes

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Academic literature on the topic 'Phosphore – Isotopes'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Phosphore – Isotopes"

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Chen, Ke, Bai Song, Navaneetha K. Ravichandran, Qiye Zheng, Xi Chen, Hwijong Lee, Haoran Sun, et al. "Ultrahigh thermal conductivity in isotope-enriched cubic boron nitride." Science 367, no. 6477 (January 9, 2020): 555–59. http://dx.doi.org/10.1126/science.aaz6149.

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Materials with high thermal conductivity (κ) are of technological importance and fundamental interest. We grew cubic boron nitride (cBN) crystals with controlled abundance of boron isotopes and measured κ greater than 1600 watts per meter-kelvin at room temperature in samples with enriched 10B or 11B. In comparison, we found that the isotope enhancement of κ is considerably lower for boron phosphide and boron arsenide as the identical isotopic mass disorder becomes increasingly invisible to phonons. The ultrahigh κ in conjunction with its wide bandgap (6.2 electron volts) makes cBN a promising material for microelectronics thermal management, high-power electronics, and optoelectronics applications.
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Barrick, Reese E., and William J. Showers. "Oxygen isotope variability in juvenile dinosaurs (Hypacrosaurus): evidence for thermoregulation." Paleobiology 21, no. 4 (1995): 552–60. http://dx.doi.org/10.1017/s0094837300013531.

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Small terrestrial vertebrates are not capable of maintaining a constant body temperature (±2°C) without a relatively high metabolism. The amount of temperature variability during bone growth can be determined using oxygen isotopes from bone phosphate because fractionation of oxygen isotopes between body fluid and bone phosphate is dependent upon temperature. Fluctuation of body temperature during the early phase of growth in juvenile ectotherms should result in high intra- and interbone isotopic variability, whereas juvenile endotherms should have low isotopic variability resulting from the maintenance of homeothermy. Analyses of juvenile Hypacrosaurus individuals indicate a pattern of low isotopic heterogeneity suggestive of endothermy.
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Ford, William, Mark R. Williams, Megan B. Young, Kevin W. King, and Eric Fischer. "Assessing Intra-Event Phosphorus Dynamics in Drainage Water Using Phosphate Stable Oxygen Isotopes." Transactions of the ASABE 61, no. 4 (2018): 1379–92. http://dx.doi.org/10.13031/trans.12804.

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Abstract. Quantifying fluxes and pathways of dissolved reactive phosphorus (DRP) in tile-drained landscapes has been hampered by a lack of measurements that are sensitive to P fate and transport processes. One potential tool to help understand these dynamics is the oxygen isotope signature of phosphate (d18OPO4); however, its potential benefits and limitations are not well understood for intra-event dynamics at the field scale. The objectives of this study were to quantify intra-event variability of d18OPO4 signatures in tile drainage water and assess the efficacy of d18OPO4 to elucidate mechanisms and flow pathways controlling DRP transport to tile drains. We collected water samples during a summer storm event from a subsurface (tile)-drained field located in west-central Ohio and analyzed for d18OPO4 of DRP. Supplementary water quality measurements, hydrologic modeling, and soil temperature data were used to help understand intra-event d18OPO4 dynamics. Results of the soil extraction analysis from our study site highlight that the soil water-extractable P (WEP) pool was not in equilibrium with long-term, temperature-dependent water isotope values. This result suggests that P-rich soils may, at least partially, retain their original source signature, which has significant implications for identifying hotspots of P delivery in watershed-scale applications. Results of the storm event analysis highlight that equilibration of leached DRP in soil water creates a gradient between isotopic compositions of pre-event shallow subsurface sources, pre-event deep subsurface sources, and the WEP tied up in surface soils. The current study represents the first intra-event analysis of d18OPO4 and highlights the potential for phosphate oxygen isotopes as a novel tool to improve understanding of P fate and transport in artificially drained agroecosystems. Keywords: Agriculture, Edge-of-field, Macropores, Phosphate oxygen isotopes, Tile-drainage.
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Navarro, Nicolas, Christophe Lécuyer, Sophie Montuire, Cyril Langlois, and François Martineau. "Oxygen isotope compositions of phosphate from arvicoline teeth and Quaternary climatic changes, Gigny, French Jura." Quaternary Research 62, no. 2 (September 2004): 172–82. http://dx.doi.org/10.1016/j.yqres.2004.06.001.

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Oxygen isotope compositions of biogenic phosphates from mammals are widely used as proxies of the isotopic compositions of meteoric waters that are roughly linearly related to the air temperature at high- and mid-latitudes. An oxygen isotope fractionation equation was determined by using present-day European arvicoline (rodents) tooth phosphate: δ18Op = 20.98(±0.59) + 0.572(±0.065) δ18Ow. This fractionation equation was applied to the Late Pleistocene karstic sequence of Gigny, French Jura. Comparison between the oxygen isotope compositions of arvicoline tooth phosphate and Greenland ice core records suggests to reconsider the previously established hypothetical chronology of the sequence. According to the δ18O value of meteoric water–mean air temperature relationships, the δ18O value of arvicoline teeth records variations in mean air temperatures that range from 0° to 15°C.
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Lisowska-Gaczorek, Aleksandra, Krzysztof Szostek, Jacek Pawlyta, and Beata Cienkosz-Stepańczak. "Oxygen isotopic fractionation in rat bones as a result of consuming thermally processed water – bioarchaeological applications." Geochronometria 47, no. 1 (May 4, 2020): 1–12. http://dx.doi.org/10.2478/geochr-2020-0001.

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AbstractStable isotope analyses of oxygen are used in anthropology for such purposes as determination of origin of individuals, tracking migration routes or dynamics of human community relocation. The methodology related to oxygen isotope analysis has been founded on the relationship between its isotopic composition within phosphate groups of bone tissue (δ18Op) in individuals being analysed and the water consumed by such individuals (δ18Ow). Such a relationship has been observed in many species of mammals, including humans. However, the influence of culinary practices on the isotopic delta values of apatite phosphates of individuals has not yet been researched. The present study, which was conducted using laboratory rats, is an investigation of the influence of the thermal processing of water drank by such rats on the isotopic composition (δ18Op) of bone apatite. Increasing the value of the isotopic composition of water by about 6.1 ‰ during boiling resulted in an increase in the oxygen isotopic value δ18Op of rats drinking the water by about 4 ‰ (29%). It can be expected that regular consumption of heavily isotopic drinks and foods by humans may cause the δ18Op of individuals to exceed the range of isotopic environmental variability, even by a few per mille.
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Vickers, J. D., and J. F. Mustard. "The phosphoinositides exist in multiple metabolic pools in rabbit platelets." Biochemical Journal 238, no. 2 (September 1, 1986): 411–17. http://dx.doi.org/10.1042/bj2380411.

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The labelling of the phosphoinositides and phosphatidic acid in washed rabbit platelets incubated with [32P]phosphate or [3H]glycerol was studied in the presence of isotope and after unincorporated isotope had been removed. With both isotopes the increase in the specific radioactivity of phosphatidylinositol 4,5-bisphosphate (PIP2) lagged behind that of phosphatidylinositol 4-phosphate (PIP) but the specific radioactivity remained higher after unincorporated isotope had been removed. This result was consistent with the presence of a second pool of PIP2, which interconverted slowly with the pool of PIP2 which was in direct equilibrium with PIP, proposed to explain the increase in specific radioactivity of PIP2 which accompanies the decrease in amount of PIP2 at 10 s in ADP-stimulated platelets. In platelets labelled with [3H]glycerol, the specific radioactivity of PIP2 became higher than that of PIP and the specific radioactivity of PIP became higher than that of phosphatidylinositol (PI). These results were interpreted to indicate that there were two pools of PIP; of these the pool with the higher specific radioactivity was the precursor of PIP2. Similarly, two pools of PI were proposed. The presence of pools of the phosphoinositides with different specific radioactivities necessitates the measurement of chemical amount of these compounds when studying the effect of stimulation of the platelets, since changes in labelling may not accurately reflect changes in the amount of the phosphoinositides.
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Nagatsuka, Naoko, Nozomu Takeuchi, Ki-Cheol Shin, and Takanori Nakano. "Spatial variations of Sr–Nd isotopic ratios, mineralogical and elemental compositions of cryoconite in an Alaskan glacier." Annals of Glaciology 59, no. 77 (December 2018): 147–58. http://dx.doi.org/10.1017/aog.2019.2.

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ABSTRACTTo understand the geological origins of minerals in cryoconite and the nutrients sources for microbes on glaciers, we analyzed the Sr–Nd isotopic ratios of the four mineral fractions in cryoconites including saline, carbonate, phosphate, silicate and the organic fraction obtained from Gulkana Glacier in Alaska. The isotopes in the silicate mineral fraction exhibited spatial variation within the glacier (87Sr/86Sr: 0.704533–0.709563, εNd (0): −16.0 to 0.5), which can be explained by the different mixing ratios of the two distinct sources: one of the sources is lateral and terminal moraines or soil, and the other is the medial moraine of the glacier. The minerals in the cryoconite at the lower sites in the glacier are likely derived from the former source, whereas those at the upper sites are from latter sources. The mineralogical and elemental compositions also support mixing of the silicate minerals from the two local sources. The Sr isotopic ratios of the organic fraction also showed spatial variation on the glacier in the middle sites – a trend similar to those of the phosphate fraction. The results suggest that the organic matter is mostly the byproducts of microbes using the phosphate minerals as a nutrient source.
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v. Sperber, C., F. Tamburini, B. Brunner, S. M. Bernasconi, and E. Frossard. "The oxygen isotope composition of phosphate released from phytic acid by the activity of wheat and <i>Aspergillus niger</i> phytase." Biogeosciences Discussions 12, no. 6 (March 30, 2015): 5055–77. http://dx.doi.org/10.5194/bgd-12-5055-2015.

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Abstract. Phosphorus (P) is an essential nutrient for living organisms. Under P-limiting conditions plants and microorganisms can exude extracellular phosphatases that release inorganic phosphate (Pi) from organic phosphorus compounds (Porg). Phytic acid (IP6) is an important form of Porg in many soils. The enzymatic hydrolysis of IP6 by phytase yields plant available inorganic phosphate (Pi) and less phosphorylated inositol derivates as products. The hydrolysis of organic P-compounds by phosphatases leaves an isotopic imprint on the oxygen isotope composition (δ18O) of released Pi, which might be used to trace P in the environment. This study aims at determining the effect of phytase on the oxygen isotope composition of released Pi. For this purpose, enzymatic assays with histidine acid phytases from wheat and Aspergillus niger were prepared using IP6, adenosine 5'monophosphate (AMP) and glycerophosphate (GPO4) as substrates. For a comparison to the δ18O of Pi released by other extracellular enzymes, enzymatic assays with acid phosphatases from potato and wheat germ with IP6 as substrate were prepared. During the hydrolysis of IP6 by phytase, four Pi are released, and one oxygen atom from water is incorporated into each Pi. This incorporation of oxygen from water into Pi is subject to an apparent inverse isotopic fractionation (&amp;varepsilon; ∼ 6 to 10‰), which is similar to that imparted by acid phosphatase from potato during the hydrolysis of IP6 (&amp;varepsilon; ∼ 7‰) where less than three Pi are released. The incorporation of oxygen from water into Pi during the hydrolysis of AMP and GPO4 by phytase yielded a normal isotopic fractionation (&amp;varepsilon; ∼ −12‰), again similar to values reported for acid phosphatases from potato and wheat germ. We attribute this similarity in ε to the same amino acid sequence motif (RHGXRXP) at the active site of these enzymes, which leads to similar reaction mechanisms. We suggest that the striking substrate-dependency of the isotopic fractionation could be attributed to a difference in the δ18O-values of the C-O-P bridging and non-bridging oxygen atoms in organic phosphate compounds.
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Matveyeva, Ilona, Fatima Meiirman, Nurgul Nursapina, Bagdat Satybaldiyev, Tamara Tuzova, Zhandos Shalabayev, and Balnur Shynybek. "Concentration of uranium isotopes by in-situ coprecipitation on activated coal and iron (III) hydroxide." Chemical Bulletin of Kazakh National University, no. 1 (March 29, 2019): 4–11. http://dx.doi.org/10.15328/cb1000.

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The use of the method of nonequilibrium uranium in various branches of science led to the necessity to determine its isotopic composition. The content of uranium isotopes in natural waters is often extremely low, therefore, it is necessary to collect significant volumes of samples in order to obtain reliable results of analysis. In this paper, it is proposed to concentrate uranium isotopes from water in-situ. Two alternative methods of uranium coprecipitation in field conditions (on activated carbon and iron (III) hydroxide) are considered. The desorbed uranium isotopes are determined by an alpha-spectrometric method with preliminary radiochemical preparation in laboratory conditions, including extraction with tributyl phosphate and electrodeposition on a steel disc. It was found that when concentrating on activated carbon the chemical yield was from 2 to 32%, and when concentrating on iron (III) hydroxide it is from 15 to 62%. For the second case, the chemical yield is acceptable for radiochemical work, and the proposed method for concentrating of uranium isotopes is recommended for usage in field conditions. Approbation of the method was carried out within the framework of the PEER454 project in 2017 in the valley of the river Ziddy, Pamir-Alay, Republic of Tajikistan. Work in the field conditions showed high efficiency of the method and its full feasibility even in the absence of acceptable laboratory conditions.
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Sauze, Joana, Sam P. Jones, Lisa Wingate, Steven Wohl, and Jérôme Ogée. "The role of soil pH on soil carbonic anhydrase activity." Biogeosciences 15, no. 2 (January 30, 2018): 597–612. http://dx.doi.org/10.5194/bg-15-597-2018.

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Abstract. Carbonic anhydrases (CAs) are metalloenzymes present in plants and microorganisms that catalyse the interconversion of CO2 and water to bicarbonate and protons. Because oxygen isotopes are also exchanged during this reaction, the presence of CA also modifies the contribution of soil and plant CO18O fluxes to the global budget of atmospheric CO18O. The oxygen isotope signatures (δ18O) of these fluxes differ as leaf water pools are usually more enriched than soil water pools, and this difference is used to partition the net CO2 flux over land into soil respiration and plant photosynthesis. Nonetheless, the use of atmospheric CO18O as a tracer of land surface CO2 fluxes requires a good knowledge of soil CA activity. Previous studies have shown that significant differences in soil CA activity are found in different biomes and seasons, but our understanding of the environmental and ecological drivers responsible for the spatial and temporal patterns observed in soil CA activity is still limited. One factor that has been overlooked so far is pH. Soil pH is known to strongly influence microbial community composition, richness and diversity in addition to governing the speciation of CO2 between the different carbonate forms. In this study we investigated the CO2–H2O isotopic exchange rate (kiso) in six soils with pH varying from 4.5 to 8.5. We also artificially increased the soil CA concentration to test how pH and other soil properties (texture and phosphate content) affected the relationship between kiso and CA concentration. We found that soil pH was the primary driver of kiso after CA addition and that the chemical composition (i.e. phosphate content) played only a secondary role. We also found an offset between the δ18O of the water pool with which CO2 equilibrates and total soil water (i.e. water extracted by vacuum distillation) that varied with soil texture. The reasons for this offset are still unknown.
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Dissertations / Theses on the topic "Phosphore – Isotopes"

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Pouységu, Laurent. "Détermination structurale de sucres par RMN 29Si,13C et 31P : expériences INEPT et DEPT associées à des simulations de spectres." Bordeaux 1, 1997. http://www.theses.fr/1997BOR10583.

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UNE METHODE GENERALE DE DETERMINATION STRUCTURALE DES SUCRES PAR RMN 29Si,13C et 31P A ETE DEVELOPPEE. L'EXPLOITATION DES PROPRIETES DES SEQUENCES INEPT (NON REFOCALISE, REFOCALISE-DECOUPLE 1D OU 2D) ET DEPT ETENDU PERMET DE REALISER L'ANALYSE CONFORMATIONNELLE D'HEXOPYRANOSES DIVERSEMENT SUBSTITUES. ASSOCIEES A DES SIMULATIONS DE SPECTRES, CES EXPERIENCES CONDUISENT A LA LOCALISATION DES SUBSTITUANTS SUR LE CYCLE PYRANOSIQUE, AINSI QU'A L'ATTRIBUTION DES ATOMES DE CARBONE CYCLIQUES. UNE PROPRIETE DE COUPLAGE HOMONUCLEAIRE 31P-31P (INTERACTION DE TYPE COORDINATIF) A EGALEMENT ETE OBSERVEE POUR LA PREMIERE FOIS LORS DE L'ANALYSE DE SUCRES PERPHOSPHITYLES.
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Petit, Sébastien. "Interaction d'échanges et résonance magnétique nucléaire du phosphore 31 dans les phosphates de vanadium." Lyon, École normale supérieure (sciences), 2003. http://www.theses.fr/2003ENSL0256.

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Zaim, Wadghiri Youssef. "Méthodologies pour l'utilisation clinique de la spectroscopie RMN : cas du phosphore-31 ; quantification ; mesures thermométriques." Lyon 1, 1994. http://www.theses.fr/1994LYO10349.

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Le chapitre i du manuscrit fait un appel succinct des bases physiques de la spectroscopie rmn. Les methodes recentes employees et les applications medicales de la spectroscopie rmn du 31p in vivo y sont egalement decrites et une attention particuliere est portee sur l'etude du muscle et du cerveau. Le chapitre ii concerne les developpements techniques elabores pour l'observation in vivo du phosphore-31 dans un aimant a 4,7 tesla de diametre utile 36 cm. Cette partie du travail a porte notamment sur la realisation d'un ergometre permettant de correler travail musculaire et spectres rmn et sur la conception d'une antenne adaptee a une couveuse pour l'observation du cerveau chez le nouveau-ne. Le chapitre iii est consacre a l'optimisation d'une methode parametrique de quantification des signaux rmn in vivo developpee au laboratoire. Cette methode est actuellement utilisee pour l'analyse automatique des spectres rmn obtenus au cours de cinetiques. Le dernier chapitre aborde les effets d'echauffements radiofrequence pouvant etre occasionnees au cours d'une experience de rmn a champ eleve, notamment en spectroscopie in vivo. Une methode de cartographie de temperature mettant a profit la dependance du deplacement chimique du noyau de cobalt-59 vis a vis de la temperature est proposee
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Pimmel, Pierre. "Les antennes en résonance magnétique nucléaire : fonctionnement et réalisation : résonateurs pour l'imagerie et pour la spectroscopie in vivo." Lyon 1, 1990. http://www.theses.fr/1990LYO10101.

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Dans la premiere partie est presentee une analyse detaillee du fonctionnement des antennes rmn. Une attention particuliere est portee aux divers montages permettant l'adaptation d'impedance. Plusieurs methodes de caracterisation des antennes sont indiquees. Des montages a accord multiple sont decrits, ainsi que quelques solutions pratiques au probleme du decouplage de deux antennes. Les deux parties suivantes sont consacrees aux applications a l'imagerie et a la spectroscopie in vivo. Les avantages que l'on peut tirer de la structure d'une antenne pour ameliorer sa sensibilite sont exploites dans un premier temps en imagerie rmn. C'est ainsi qu'une antenne pour l'examen pediatrique cardique a ete developpee en relation avec general electric cgr. De plus une version hybride de l'antenne cage d'oiseau est proposee pour l'observation du sodium a 4,7 tesla. Les applications a la spectroscopie in vivo en #3#1p portent sur les questions de quantification liees a l'utilisation d'antennes de surface et d'antennes globales. Une premiere categorie d'antennes de surface est utilisee pour l'examen musculaire chez l'homme, une seconde categorie est destinee aux etudes du metabolisme sur modeles animaux. Les antennes globales sont reservees a l'etude du metabolisme sur modeles animaux. Les antennes globales sont reserves a l'etude d'organes excises. L'etude presentee etablit le lien entre la formation du signal rmn, sa detection, son traitement et l'utilisation des resultats en vue de quantification des metabolites in vivo
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Mattei, Jean-Pierre. "Approches cliniques du métabolisme énergétique musculaire par spectrométrie de résonance magnétique du phosphore-31 : avantages, limites et perspectives." Aix-Marseille 2, 2002. http://www.theses.fr/2002AIX20688.

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Chaumeil, Myriam. "Mesure du métabolisme énérgétique cérébral par RMN du 31P in vivo : validation méthodologique multimodale et application à l'étude de la neurodégénérescence." Paris 11, 2008. http://www.theses.fr/2008PA112365.

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Au cours des dernières décennies, des techniques de neuroimagerie atraumatiques et non invasives visant à évaluer les flux métaboliques cérébraux ont été développées. Parmi elles, la spectroscopie par résonance magnétique (SRM) du 31P présente l'avantage de permettre la mesure directe du flux cérébral de synthèse d'ATP, mais apparaît encore à ce jour un défi méthodologique. Dans une première étude de neuroimagerie multimodale, la consommation régionale de glucose CMRglc, la vitesse du cycle de Krebs (Vtca) et la vitesse de synthèse d'ATP (Vatp) ont été mesurées dans le cerveau de primate sain respectivement par TEP (tomographie par émission de positrons) 18F-FDG, SRM du 13C et transfert de saturation par SRM du 31P. La cohérence de ces trois flux a permis de valider la méthode de transfert de saturation par SRM du 31P pour la mesure directe de Vatp cérébrale. L'intérêt de la SRM du 31P a ensuite été évalué sur des patients atteints de la maladie de Huntington (MH). Un maintien de l’homéostasie métabolique, une diminution non significative de Vatp, et une augmentation significative du pH ont été mis en évidence dans le cerveau de ces patients. L'alcalinisation cérébrale, pour la première fois mesurée dans la MH, présentait de plus une corrélation avec les scores cliniques moteurs. Au vu de ce résultat, une étude visant à évaluer la précocité des variations de pH associées à la MH a été réalisée sur un modèle rongeur au cours d'une intoxication chronique à l'acide 3-nitropropionique (3NP). Une augmentation significative du pH précédant l'apparition de lésions striatales a été mise en évidence, démontrant la potentialité du pH comme biomarqueur précoce de la MH
Neuroimaging methods have considerably developed over the last decades and offer various non-invasive approaches for measuring cerebral metabolic fluxes. Among these methods, 31P magnetic resonance spectroscopy (MRS) has the particularity to directly measure cerebral ATP synthesis, but is still methodologically challenging. In this context, a multimodal neuroimaging study was performed in order to validate the saturation transfer 31P MRS method as a quantitative measurement of brain ATP synthesis. Glucose consumption (CMRglc), TCA cycle flux (Vtca ) and rate of ATP synthesis (Vatp) were measured in primate monkeys using 18F-FDG PET scan, indirect 13C MRS and saturation transfer 31P MRS, respectively. The consistency of these three fluxes with literature and, more interestingly, one with each other, demonstrated the robustness of saturation transfer 31 P MRS for directly evaluating ATP synthesis in the living brain. The potential of 31P MRS was then evaluated on Huntington's disease patients. Stability of metabolic homeostasis, non-significant decrease in Vatp, and significant increase in cerebral pH were shown in HD patient's brain. The increase in cerebral pH, detected for the first time in MH, was correlated with motor scores. Given these results, in order to assess the precocity of pH variations associated with MH, a study was performed on a rodent chronic model of MH. A significant increase in cerebral pH was detected before any lesions evidence, showing the potentiality of pH measurement as early biomarker of MH
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SEGUINEAU, PASCALE. "Les reactions de wittig et wittig-horner en milieu protique peu basique." Nantes, 1989. http://www.theses.fr/1989NANT2014.

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La reaction de wittig-horner realisee dans des conditions douces (milieu aqueux peu basique) a l'aide de composes dicarbonyles permet d'acceder par bisaldolisation a des cyclenols alpha -fonctionnalises. Grace a cette technique douce, la reaction de wittig-horner est chimioselective et ne s'effectue que sur les sites carbonyles tres actifs (aldehydes)
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Brédoire, Félix. "Impacts of global change on the biogeochemical cycling of water and nutrients in the soil-plant system and consequences for vegetation growth in south-western Siberia." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0033/document.

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Dans un contexte de changement global, prédire l’évolution de la productivité de la végétation dans le sud-ouest (SO) Sibérien reste un défi du fait d’incertitudes fortes sur les processus régulant la disponibilité en eau et en nutriments. Nous avons mis en évidence des relations entre cycles biogéochimiques, climat et propriétés du sol sur six sites contrastés.La croissance radiale des tiges de peuplier est principalement sensible au bilan hydrique du sol en forêt de steppe, au sud du SO Sibérien, alors qu’elle est stimulée par de hautes températures estivales en sub-taïga, dans le nord de la région.Des mesures de terrain et des simulations du bilan hydrique du sol ont montré que la fonte des neiges est importante pour la recharge des réserves hydriques du sol au sud. Au nord, ces réserves sont souvent rechargées en automne. La fonte des neiges est alors associée à du drainage. De plus, au nord, une épaisse couverture de neige protège le sol du gel en hiver. La distribution des racines fines est plus profonde en forêt de steppe qu’en sub-taïga, impactée par le déficit hydrique et le gel.L’homogénéité du statut en phosphore (P) des sols dans le SO Sibérien montre qu’il n’est pas encore très impacté par la pédogénèse. Les stocks en P élevés, notammen tles formes disponibles pour les plantes, suggèrent que le P n’est pas et ne sera pas limitant dans le futur.La décomposition des litières aériennes et la libération de l’azote (N) sont plus rapides en sub-taïga qu’en forêt de steppe. Un fort drainage pourrait expliquer un transfert profond du N dans les sols en sub-taïga. Cependant ces sols semblent efficaces pour retenir le N, limitant les pertes pour le système sol–plante
Predicting the evolution of vegetation productivity in SW Siberia in the contextof global change remains a challenge because of major uncertainties concerningthe biogeochemical cycling and the plant-availability of water and nutrients. Weprovided insights on their relation to climate and soil properties, investigating sixcontrasting sites.Aspen stem radial growth is mainly sensitive to soil water budget in the foreststeppezone established in the south of SW Siberia while it is enhanced by highsummer temperatures in the sub-taiga, in the north of the region.Field measurements and water budget simulations revealed that snow-melt isimportant re-filling soil water reserves in the south. In the north, these reservesare mostly re-filled in autumn and snow-melt is associated with drainage. A thicksnow-pack also prevents soil from freezing in winter in the sub-taiga. Water deficitand soil freezing largely impact the distribution of fine roots within the soil profilewhich is deeper in forest-steppe than in sub-taiga.The homogeneous soil phosphorus (P) status in the region investigated revealedthis nutrient has not been yet very impacted by contrasting soil processes. High Pstocks, and in particular plant-available forms, suggest P is unlikely to be limitingunder current and future conditions.By contrast, we found differences in nitrogen (N) status. Above-ground litterdecay and the release of N occurs faster in sub-taiga than in forest-steppe. Higherdrainage may explain deeper N transfer in sub-taiga soils. However, sub-taiga soilsalso seem to be efficient in retaining N, limiting losses from the soil–plant system
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Abrahão, Anna 1988. "Estratégias de forrageamento de plantas em campos rupestres da Cadeia do Espinhaço, MG, Brasil = aquisição e uso de nitrogênio e fósforo = Plant foraging strategies in rupestrian fields from the Espinhaço range, Minas Gerais, Brazil: nitrogen and phosphorus acquisition and use." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316209.

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Orientador: Rafael Silva Oliveira
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Apesar da grande diversidade de espécies de plantas nativas de solos tropicais e pobres em nutrientes, pouco se sabe sobre a diversidade de mecanismos de aquisição e uso de nutrientes nesses ambientes. Nesse contexto, o objetivo desse estudo foi entender como ocorre à aquisição e o uso de nitrogênio (N) e fósforo (P) em fisionomias rupestres de cerrado na Cadeia do Espinhaço, em Minas Gerais, sudeste do Brasil, em ambiente muito pobre em nutrientes. No primeiro capítulo, nós descrevemos e investigamos o status micorrízico e o papel funcional da especialização radicular de Discocactus placentiformis (Cactaceae), uma espécie abundante de campos rupestres na Cadeia do Espinhaço. As raízes possuem pelos abundantes que aderem grãos de areia. A nossa hipótese foi que as raízes de D. placentiformis não possuem colonização por micorrizas, e funcionam de forma similar a cluster roots, aumentando a liberação de ácidos orgânicos quando submetidas à deficiência de P. Nós não observamos colonização por micorrizas nas raízes de D. placentiformis. Ao coletar e analisar os exsudatos radiculares identificou ácido oxálico, málico, cítrico, láctico, succínico, fumárico e malônico, em ordem decrescente de concentração. Como esperado, a exsudação total aumentou com a deficiência de P. O papel ecofisiológico dessa nova especialização radicular parece ser semelhante ao de raízes do tipo cluster roots. Esses resultados sugerem uma convergência funcional entre estratégias nutricionais de plantas em hábitats pobres em nutrientes. No segundo capítulo, em nível de comunidade, comparamos as assinaturas isotópicas de N (?15N) e a colonização por micorrizas dos representantes mais abundantes de três fisionomias rupestres de cerrado, com disponibilidades distintas de N no solo (campos rupestres, campos úmidos e cerrados ralos). Nós testamos a hipótese de que o ?15N foliar aumenta com o N total no solo e que as fisionomias mais pobres em N apresentam um maior intervalo de valores de ?15N foliar, possuindo então maior diversidade de estratégias de aquisição de N. Em todas as fisionomias nós observamos uma disponibilidade de nitrogênio muito baixa, principalmente nos campos rupestres. Ao contrário do esperado, nós observamos uma relação negativa entre os valores de ?15N foliar e o N total no solo. Apesar das diferenças de nitrogênio no solo, os valores de N foliar foram similares entre as fisionomias. Os resultados também mostram que o maior intervalo de valores de ?15N foliar não está associado com o ambiente com menor valor de N total no solo. No entanto, como esperado, a grande variação nos valores de ?15N foliar aponta a diversidade de mecanismos de aquisição de nitrogênio. A eficiência na aquisição de fósforo por meio de especializações radiculares e a diversidade de mecanismos de absorção de nitrogênio podem ajudar a manter a grande diversidade de espécies nesses ambientes rupestres. Além disso, parece haver uma convergência funcional destes ambientes pobres em nutrientes da América do Sul com ambientes pobres em nutrientes de outras partes do mundo
Abstract: Despite the great plant species richness in tropical and nutrient-poor soils, little is known about nutrient-acquisition strategies in these environments. In this context, the aim of this work was to understand the acquisition and use of nutrients in a nutrient-impoverished site in Brazil. Therefore, we studied nitrogen and phosphorus acquisition and use in rupestrian physiognomies at the Espinhaço mountain range, in Minas Gerais, southeastern Brazil. In the first chapter, we described and investigated a sand-binding root specialization of Discocactus placentiformis (Cactaceae), a common species in rupestrian grasslands white sands. We hypothesized that D. placentiformis is non-micorrhizal and increases organic acid release when submitted to P deficiency. We collected and analyzed root exudates from plants subjected to different phosphorus supplies. We identified oxalic, malic, citric, and lactic, succinic fumaric and malonic acids, in decreasing order of concentration. As expected, total exudation decreased with P supply. These results show that the ecophysiological role of this root specialization seems to be similar to cluster roots, pointing towards a functional global convergence in nutrient-acquisition strategies between plants from nutrient-poor habitats. In the second chapter, at the community level, we compared N isotopic signatures (?15N), from the most abundant species in three rupestrian cerrado communities (rupestrian fields, humid fields and shrublands). We tested the hypothesis that foliar ?15N values increases with N availability, and that physiognomies with lower N availability present a higher range of foliar ?15N values. In all the physiognomies, we observed a very low N availability, especially in the rupestrian grasslands. Contrary to expectations, we observed a negative relation between foliar ?15N values and total soil N. Despite the differences in soil N, total foliar N values were similar among physiognomies. These results show that higher foliar ?15N do not always indicate higher soil N availability and that the widest range of foliar ?15N is not always associated with lowest total soil N. However, as expected, we observed a high range in foliar ?15N, indicating diversity in N-acquisition strategies. The efficiency in phosphorus acquisition by root specializations and the diversity in nitrogen-acquisition mechanisms may help maintaining the high species diversity in these habitats. Additionally, there seems to be a functional convergence between rupestrian communities and other nutrient-poor sites in the world
Mestrado
Ecologia
Mestra em Ecologia
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Duffy, Margaret R. "Determining the biological turnover rate of phosphate in agricultural soils using stable oxygen isotopes." Bowling Green State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1593864445251739.

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Books on the topic "Phosphore – Isotopes"

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Ballance, Peter E. Phosphorus-32: Practical radiation protection. Northwood: Science Reviews in association with H & H Scientific Consultants, 1987.

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Ballance, Peter E. Phosphorus-32: Practical radiation protection. Leeds: H and H Scientific Consultants Ltd., 1992.

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Burnett, William C. Release of radium and other decay-series isotopes from Florida phosphate rock: Final report. Bartow, Fla. (1855 W. Main St., Bartow 33830): The Institute, 1988.

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Waser, Nathalie Anne Danielle. Cosmogenic ³²P and ³³P in the atmosphere and aligotrophic ocean and applications to the study of phosphorus cycling. [Wood Hole, Mass: Woods Hole Oceanographic Institution, 1993.

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1933-, Tebby John C., ed. CRC handbook of phosphorus-31 nuclear magnetic resonance data. Boca Raton: CRC Press, 1991.

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Tebby, John C. Handbook of Phosphorus-31 Nuclear Magnetic Resonance Data. CRC Press, 1990.

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H, Phillips D., Castegnaro M. 1944-, Bartsch H, International Agency for Research on Cancer., United States. Environmental Protection Agency., and Germany Ministry of Health, eds. Postlabelling methods for detection of DNA adducts. Lyon: International Agency for Research on Cancer, 1993.

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Phillips, D. H. Postlabelling Methods for Detection of DNA Adducts. IARC Scientific Publications, 1993.

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1942-, Burt C. Tyler, ed. Phosphorus NMR in biology. Boca Raton, Fla: CRC Press, 1987.

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1935-, Verkade John G., and Quin Louis D. 1928-, eds. Phosphorus-31 NMR spectroscopy in stereochemical analysis. Deerfield Beach, Fla: VCH Publishers, 1987.

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Book chapters on the topic "Phosphore – Isotopes"

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Paytan, Adina, and Karen McLaughlin. "Tracing the Sources and Biogeochemical Cycling of Phosphorus in Aquatic Systems Using Isotopes of Oxygen in Phosphate." In Advances in Isotope Geochemistry, 419–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-10637-8_21.

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Jaisi, Deb P., Ruth E. Blake, Yuhong Liang, and Sae Jung Chang. "Investigation of Compound-Specific Organic-Inorganic Phosphorus Transformation Using Stable Isotope Ratios in Phosphate." In Applied Manure and Nutrient Chemistry for Sustainable Agriculture and Environment, 267–92. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-8807-6_13.

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Schomäcker, K., B. Meller-Rehbein, B. Gabruk-Szostak, H. Gerard, K. Scheidhauer, A. Scharl, M. Bähre, E. Richter, and H. Schicha. "Investigations into Biokinetics of I-123-Diethylstilbestrol Phosphate (DSEP) in Tumor-Bearing Mice." In Radioactive Isotopes in Clinical Medicine and Research, 333–42. Basel: Birkhäuser Basel, 1997. http://dx.doi.org/10.1007/978-3-0348-7772-5_50.

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Mayr, Christoph, Gisela Grupe, Anita Toncala, and Christina M. Lihl. "Linking Oxygen Isotopes of Animal-Bone Phosphate with Altimetry: Results from Archaeological Finds from a Transect in the Alps." In Isotopic Landscapes in Bioarchaeology, 157–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-48339-8_9.

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Zhang, Guoan, and Thomas A. Neubert. "Use of Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC) for Phosphotyrosine Protein Identification and Quantitation." In Phospho-Proteomics, 79–92. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-60327-834-8_7.

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Cruz-Paredes, Carla, and Mayra E. Gavito. "Isotope Labeling to Study Phosphorus Uptake in the Arbuscular Mycorrhizal Symbiosis." In Methods in Molecular Biology, 213–22. New York, NY: Springer US, 2020. http://dx.doi.org/10.1007/978-1-0716-0603-2_16.

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Kumarasinghe, K. S., and D. L. Eskew. "Effects of phosphorus fertilization on growth and N accumulation in Azolla." In Isotopic Studies of Azolla and Nitrogen Fertilization of Rice, 71–78. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1681-7_10.

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Borland, Kayla, and Patrick A. Limbach. "Applications and Advantages of Stable Isotope Phosphate Labeling of RNA in Mass Spectrometry." In Phosphate Labeling and Sensing in Chemical Biology, 89–103. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-60357-5_4.

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Fakhi, Said, Rabie Outayad, Elmehdi Fait, Zineb Faiz, C. Galindo, Abderrahim Bouih, Moncef Benmansour, et al. "Sequential Extraction of U and Th Isotopes: Study of Their Intrinsic Distribution in Phosphate and Limestone Sedimentary Rock in Comparison with Black Shale." In Uranium - Past and Future Challenges, 581–90. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11059-2_66.

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Lécuyer, Christophe. "Oxygen Isotope Analysis of Phosphate." In Handbook of Stable Isotope Analytical Techniques, 482–96. Elsevier, 2004. http://dx.doi.org/10.1016/b978-044451114-0/50024-7.

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Conference papers on the topic "Phosphore – Isotopes"

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Stănescu, R., N. Vedeanu, I. B. Cozar, and A. Măgdaş. "Structural investigation of phosphate - bismuth glasses with vanadium." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2013). AIP, 2013. http://dx.doi.org/10.1063/1.4833710.

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Popa, A., R. Stefan, M. Bosca, V. Dan, V. Pop, and P. Pascuta. "EPR and magnetic susceptibility investigation of iron-zinc-phosphate glass ceramics." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2013). AIP, 2013. http://dx.doi.org/10.1063/1.4833738.

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Muresan, L. E., A. I. Cadis, I. Perhaita, B. F. Oprea, and D. T. Silipas. "The influence of synthesis methods on the morpho - structural and luminescent characteristics of rare earth silicate phosphors." In PROCESSES IN ISOTOPES AND MOLECULES (PIM 2013). AIP, 2013. http://dx.doi.org/10.1063/1.4833726.

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Chang, Sae Jung, and Ruth Blake. "Oxygen Isotope Signature during Phosphite Oxidation by Bacterial Alkaline Phosphatase." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.359.

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Sun, Xiao Xu. "Study on Variations of Isotopes and Phosphate of Soil Water in Water Infiltration Process." In 2016 5th International Conference on Energy and Environmental Protection (ICEEP 2016). Paris, France: Atlantis Press, 2016. http://dx.doi.org/10.2991/iceep-16.2016.29.

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Bouhelal, M., F. Haas, E. Caurier, and F. Nowacki. "0 and 1 ħω shell model description of phosphorus isotopes with A = 30 to 35." In NUCLEAR STRUCTURE AND DYNAMICS 2012. AIP, 2012. http://dx.doi.org/10.1063/1.4764198.

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Kendall, Brian, Su Wang, Paul Lillis, Liyan Xing, Wang Zheng, and Congxi Zhu. "EVALUATION OF MOLYBDENUM ISOTOPES AS A PETROLEUM TRACER: THE PHOSPHORIA PETROLEUM SYSTEM, BIGHORN BASIN, U.S.A." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-320149.

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Travis Taylor, Leah M., Rebecca Totten Minzoni, and Celina Suarez. "RECONSTRUCTING THE PALEOECOLOGY OF THE ALABAMA MOSASAUR CLIDASTES FROM PHOSPHATE OXYGEN ISOTOPES IN FOSSIL TOOTH ENAMEL." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-323632.

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Kelley, Dennis. "Proven Technologies for the Solidification of Complex Liquid Radioactive Waste (LRW): Global Case Studies of Applications and Disposal Options." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66081.

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Abstract:
Legacy radioactive waste streams from the Cold War still exist and newly generated waste streams from nuclear power plants and research institutes go untreated and expose environmental hazards at many nuclear sites. The nature of the waste is extremely diverse, depending upon the source or the process from which it originated. The most problematic waste streams include complex liquids such as organic (tri-butyl-phosphate TBP) solutions contaminated with Pu and U isotopes, mixed sludge types, high acid radioactive waste, H-3 tritium contaminated organic and aqueous streams, etc. Environmental and economic challenges exist for the treatment and disposal of such waste streams. A proven technology that has been applied to LRW on a global basis provides a low-cost solution to legacy streams and small volume, highly complex LRW frequently generated from routine NPP operations, in nuclear laboratories and during decommissioning. The engineered polymer technology from Nochar, USA, is capable of solidifying standard and highly complex LLW and ILW waste streams for interim or final storage, or for incineration.
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Barbecot, Florent, Marina Tcaci, Jean-François Helie, Ben W. J. Surridge, and Daren C. Goody. "Removing the Barriers for Measuring Phosphate Oxygen Isotope Compositions of Low P Concentration Freshwater Samples." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.129.

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Reports on the topic "Phosphore – Isotopes"

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Scholz, Florian. Sedimentary fluxes of trace metals, radioisotopes and greenhouse gases in the southwestern Baltic Sea Cruise No. AL543, 23.08.2020 – 28.08.2020, Kiel – Kiel - SEDITRACE. GEOMAR Helmholtz Centre for Ocean Research Kiel, November 2020. http://dx.doi.org/10.3289/cr_al543.

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R/V Alkor Cruise AL543 was planned as a six-day cruise with a program of water column and sediment sampling in Kiel Bight and the western Baltic Sea. Due to restrictions related to the Covid-19 pandemic, the original plan had to be changed and the cruise was realized as six oneday cruises with sampling in Kiel Bight exclusively. The first day was dedicated to water column and sediment sampling for radionuclide analyses at Boknis Eck and Mittelgrund in Eckernförde Bay. On the remaining five days, water column, bottom water, sediment and pore water samples were collected at eleven stations covering different types of seafloor environment (grain size, redox conditions) in western Kiel Bight. The data and samples obtained on cruise AL543 will be used to investigate (i) the sedimentary cycling of bio-essential metals (e.g., nickel, zinc, and their isotopes) as a function of variable redox conditions, (ii) the impact of submarine groundwater discharge and diffusive benthic fluxes on the distribution of radium and radon as well as greenhouse gases (methane and nitrous oxide) in the water column, and (iii) to characterize and quantify the impact of coastal erosion on sedimentary iron, phosphorus and rare earth element cycling in Kiel Bight.
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