Journal articles: 'Platinum stable isotopes'

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Neu, W., G. Passler, G. Sawatzky, R. Winkler, and H. J. Kluge. "Isotope shift and hyperfine structure of stable platinum isotopes." Zeitschrift f�r Physik D Atoms, Molecules and Clusters 7, no. 2 (June 1987): 193–201. http://dx.doi.org/10.1007/bf01384588.

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Sharma, K. S., J. Vaz, R. C. Barber, F. Buchinger, J. A. Clark, J. E. Crawford, H. Fukutani, et al. "Atomic mass ratios for some stable isotopes of platinum relative to 197Au." European Physical Journal A 25, S1 (August 11, 2005): 45–46. http://dx.doi.org/10.1140/epjad/i2005-06-191-0.

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Crawford, Isobel, Daniel Layton-Matthews, Jan M. Peter, Michael G. Gadd, Alexandre Voinot, Matthew I. Leybourne, and Peir Pufahl. "Application of molybdenum and thallium isotopes as indicators of paleoredox conditions and genesis of hyper-enriched black shale deposits, Peel River, Yukon, Canada." Canadian Mineralogist 59, no. 5 (September 1, 2021): 1085–110. http://dx.doi.org/10.3749/canmin.2000099.

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ABSTRACT Hyper-enriched black shale (HEBS) deposits in northern Yukon, consist of thin (<10 cm), laterally extensive (tens of thousands of km2) stratiform sulfide mineralization layer(s) that are hyper-enriched in Ni, Mo, Zn, platinum group elements, Re, and Au. The genesis of HEBS deposits and the ambient paleoenvironment in which they formed are the subject of vigorous debate. Non-traditional stable isotopes, particularly molybdenum and thallium, are robust paleoredox indicators and we have employed these isotope systems in this study of Yukon HEBS. Systematic sampling and Mo and Tl isotopic analysis of a continuous 200 m stratigraphic section through the Yukon HEBS mineralization and footwall and hanging-wall strata at the Peel River north and south bank showings (spaced five km apart) give δ98Mo –1.24 to –0.53‰ and –8.1 to –5.2 ε-units for the mineralization and –0.70 to 0.60‰ and –6.5 to –2.0 ε-units for the unmineralized strata. These values preclude a hydrothermal origin and strongly suggest that redox processes were responsible for the Yukon HEBS mineralization. The isotopic compositions, together with rare earth element (REE) systematics (REE profile, Y positive anomalies, Ce negative anomalies, and Y/Ho values) and other bulk geochemical redox indicators (Mo, V, Re/Mo, Ni/Co, U/Th, and V/Cr) indicate that the Peel River HEBS mineralization formed because of metal scavenging from seawater in a quiescent, euxinic basinal paleoenvironment.

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A V, Anjana, Nicemon Thomas, and Antony Joseph. "Charge Radius And Neutron Skin Thickness Of Platinum And Osmium Isotopes Near The Nuclear Drip Lines." Journal of Nuclear Physics, Material Sciences, Radiation and Applications 9, no. 2 (June 20, 2022): 187–91. http://dx.doi.org/10.15415/jnp.2022.92027.

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Background: The density distributions of exotic nuclei are different from that of stable nuclei. For stable nuclei, charge radii can be obtained through electron scattering experiments. The excessive neutrons in neutron-rich nuclei make a decoupling of neutron and proton distribution and as a result nuclear skin structures are appeared.Purpose: The charge radius and the way by which nucleons are distributed can provide information about size, surface thickness and shell structure of nuclei. The information collected from such nuclei can be used for astrophysical studies to understand the origin of heavy elements. Methods: In the present study, we have made an attempt to investigate the charge radii, rms radii and skin thickness of Pt and Os isotopes. Here, the calculations were made by using the HFB solver which utilizes HO single-particle basis and iteratively diagonalizes the HFB Hamiltonian based on the Skyrme forces.Results: Here we can observe an increase in charge radius, rms radius and skin thickness with neutron number. The charge radii calculated are in good agreement with the experimental data and predictions of RCHB model. A linear dependence of skin thickness on neutron number is observed with the change in slope is noticed around N =126.Conclusion: Using HFB theory, we have analyzed the charge radius and neutron skin thickness of Pt and Os isotopes. The drip line nuclei have larger charge radius in comparison to the stable nuclei. The redistribution of the nucleons due to addition of neutrons leads to the gradual increase in neutron skin. The sudden increase of skin thickness may be due to the extra stability and shell closure around the magic number.

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Badola, Amit, S. K. Singhal, and Manoj Bhatnagar. "(n, and945) reaction cross-section of stable isotopes of Platinum and Osmium for fusion reactor technology." International Journal of Scientific Research in Physics and Applied Sciences 6, no. 5 (October 31, 2018): 125–33. http://dx.doi.org/10.26438/ijsrpas/v6i5.125133.

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Rivera, Javier, Martin Reich, Ronny Schoenberg, José María González-Jiménez, Fernando Barra, Thomas Aiglsperger, Joaquín A. Proenza, and Sebastien Carretier. "Platinum-group element and gold enrichment in soils monitored by chromium stable isotopes during weathering of ultramafic rocks." Chemical Geology 499 (November 2018): 84–99. http://dx.doi.org/10.1016/j.chemgeo.2018.09.008.

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Seshavatharam, U. V. S., and S. Lakshminarayana. "Energy, Economical, Environmental and Medical Applications of Cold Nuclear Fusion of Hydrogen with Powder and Liquid Forms of Metals." Innovation in Science and Technology 1, no. 3 (October 2022): 43–50. http://dx.doi.org/10.56397/ist.2022.10.04.

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Aim of this paper is to highlight the four major applications of Cold Nuclear fusion (CNF). Considering Google publications, NASA publications, European funding amounts and other important experimental results, we have developed a mechanism for understanding the mystery of energy liberation in CNF associated with fusion of hydrogen with metals. Apart from clean thermal energy liberation, we have identified three important applications of CNF. They are: Preparing Iridium-, Platinum-and Gold-like costly elements from Tungsten-like elements, converting high level nuclear radioactive waste into stable atomic nuclides and preparing radioactive isotopes for medical applications. It may be noted that, we have developed a common, simple and workable theoretical procedure for understanding the above applications and it needs funding for conducting experimental studies. We emphasize the point that, our proposed scientific concept of CNF is practical compared to other theoretical models of cold nuclear fusion.

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Bosley, Keith L., and Sam C. Wainright. "Effects of preservatives and acidification on the stable isotope ratios (15N:14N, 13C:12C) of two species of marine animals." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 11 (November 1, 1999): 2181–85. http://dx.doi.org/10.1139/f99-153.

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When animal tissues are prepared for stable isotope ratio analysis, they may or may not be treated with acid prior to analysis to remove carbonates and are loaded into tin or silver weigh boats for quantitative combustion. The effects of these methodological variations are poorly known. The effects of various preservation methods on isotopic compositions are also poorly known. We tested the effects of four preservation methods, (i) formalin, (ii) formalin followed by a transfer to ethanol (formalin/EtOH), (iii) saturated mercuric chloride solution, and (iv) freezing/freeze-drying, on the carbon and nitrogen isotopic composition of the muscle tissue of juvenile winter flounder (Pleuronectes americanus) and the tails (including exoskeleton) of mud shrimp (Crangon septemspinosa). Freezing and freeze-drying were the only preservation methods that did not affect stable isotope ratios of carbon and nitrogen. Formalin, formalin/EtOH, and saturated mercuric chloride solution produced significant increases in δ15N values (0.5-1.4) and decreases in δ13C values (0.6-2.3) compared with frozen samples. There was also an increase in the variability of δ15N and (or) δ13C values. We also tested the effects of acidification by comparing samples that were acidified either by fuming with concentrated HCl or by the direct application of 1 N HCl containing 1.0% platinum chloride (a combustion catalyst) to unacidified samples. Neither concentrated HCl fumes nor HCl/platinum chloride had a significant effect on the δ15N or δ13C values of either species compared with unacidified samples. Therefore, acidification may be unnecessary in the preparation of some marine animals. Finally, we compared the effects of two types of sample boats: tin and silver. We found no significant effect of boat material on the δ15N or δ13C values of either species.

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Wallner, A., K. Melber, S. Merchel, U. Ott, O. Forstner, R. Golser, W. Kutschera, A. Priller, and P. Steier. "Stable platinum isotope measurements in presolar nanodiamonds by TEAMS." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 294 (January 2013): 496–502. http://dx.doi.org/10.1016/j.nimb.2012.03.036.

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Creech, John, Joel Baker, Monica Handler, Martin Schiller, and Martin Bizzarro. "Platinum stable isotope ratio measurements by double-spike multiple collector ICPMS." Journal of Analytical Atomic Spectrometry 28, no. 6 (2013): 853. http://dx.doi.org/10.1039/c3ja50022e.

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Fry, Brian, Susan Saupe, Meredith Hullar, and Bruce J. Peterson. "Platinum-catalyzed combustion of DOC in sealed tubes for stable isotopic analysis." Marine Chemistry 41, no. 1-3 (January 1993): 187–93. http://dx.doi.org/10.1016/0304-4203(93)90118-8.

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Creech, J. B., J. A. Baker, M. R. Handler, and M. Bizzarro. "Platinum stable isotope analysis of geological standard reference materials by double-spike MC-ICPMS." Chemical Geology 363 (January 2014): 293–300. http://dx.doi.org/10.1016/j.chemgeo.2013.11.009.

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Mogessie, A., and E. F. Stumpfl. "Platinum‐group element and stable isotope geochemistry of PGM‐bearing troctolitic rocks of the Duluth Complex, Minnesota." Australian Journal of Earth Sciences 39, no. 3 (July 1992): 315–25. http://dx.doi.org/10.1080/08120099208728026.

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Mosin, O. V., V. I. Shvets, D. A. Skladnev, and I. Ignatov. "Microbic synthesis of deuterium labelled L-phenylalanine with different levels of isotopic enrichment by facultative methylotrophic bacterium brevibacterium methylicum with RMP assimilation of carbon." Biomeditsinskaya Khimiya 60, no. 4 (2014): 448–61. http://dx.doi.org/10.18097/pbmc20146004448.

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The preparative microbial synthesis of amino acids labelled with stable isotopes, including deuterium ( 2 H), suitable for biomedical applications by methylotrophic bacteria was studied using L-phenylalanine as example. This amino acid is secreted by Gram-negative aerobic facultative methylotrophic bacteria Brevibacterium methylicum, assimilating methanol via ribulose-5-monophosphate (RMP) cycle of assimilation of carbon, The data on adaptation of L-phenylalanine secreted by methylotrophic bacterium В. methylicum to the maximal concentration of deuterium in the growth medium with 98% 2 Н 2 O and 2% [ 2 Н]methanol, and biosynthesis of deuterium labelled L-phenylalanine With different levels of enrichment are presented. The strain was adapted by means of plating initial cells on firm (2% agarose) minimal growth media with an increasing gradient of 2 Н 2 O concentration from 0; 24.5; 49.0; 73.5 up to 98% 2 Н 2 O followed by subsequent selection of separate colonies stable to the action of 2 Н 2 O. These colonies were capable to produce L-phenylalanine. L-phenylalanine was extracted from growth medium by extraction with isopropanol with the subsequent cristallization in ethanol (output 0.65 g/l). The developed method of microbial synthesis allows to obtain deuterium labelled L-phenylalanine with different levels of isotopic enrichment, depending on concentration of 2 Н 2 O in growth media, from 17% (on growth medium with 24,5% 2 Н 2 O) up to 75% (on growth medium with 98% 2 Н 2 O) of deuterium in the molecule that is confirmed with the data of the electron impact (EI) mass- spectrometry analysis of methyl ethers of N-dimethylamino(naphthalene)-5-sulfochloride (dansyl) phenylalanine in these experimental conditions.

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van den Kerkhof, Alfons M., Graciela M. Sosa, Thomas Oberthür, Frank Melcher, Tobias Fusswinkel, Andreas Kronz, Klaus Simon, and István Dunkl. "The hydrothermal Waterberg platinum deposit, Mookgophong (Naboomspruit), South Africa. Part II: Quartz chemistry, fluid inclusions and geochronology." Mineralogical Magazine 82, no. 3 (April 12, 2018): 751–78. http://dx.doi.org/10.1180/mgm.2018.80.

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AbstractThe historic Waterberg platinum deposit, ~15 km WNW of Mookgophong (formerly Naboomspruit), Limpopo Province, South Africa, is a rare fault-bound hydrothermal vein-type quartz-hematite-platinum-group mineralization. As a continuation of the geochemistry and ore mineralogy studies (Part I, Oberthür et al., 2018), this paper concentrates on the ore-bearing quartz and on the age constraints of ore formation. The state-of-the-art methods used include cathodoluminescence microscopy, electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of trace elements, stable isotope (δ18O) analysis and fluid-inclusion studies. U-Pb and (U-Th)/He radiometric age determination gave ages of 900–1075 Ma suggesting platinum-group element (PGE) mineralization as a result of upwelling fluids with connection to the Bushveld complex during Kibaran tectonic movements along the Thabazimbi–Murchison Lineament. Felsic fragments containing Qtz-1 were cemented by different quartz generations (Qtz-2 to Qtz-4) and enable the characterization of the changing physicochemical parameters during multistage mineralization and cooling. The PGE minerals are associated with the earliest hydrothermal stage represented by botryoidal radial-fibrous quartz aggregates (Qtz-2a) which formed on brecciated felsite. The other quartz types are essentially barren. Cathodoluminescence studies of quartz indicate very high Al, Fe and K concentrations as confirmed by EPMA and LA-ICP-MS, whereas Ti is always very low. The varying Al concentrations in the quartz mainly indicate pH fluctuations, the high Fe3+ points at high oxygen fugacity. Micro-inclusions of iron oxide are associated with Pt ore (Fe, Pt, Pd, Au, W, Sb, As), rutile, kaolinite and muscovite. The hydrothermal activity must have been characterized by low saline (<10 wt%) H2O–NaCl solutions. These fluids mixed with original high-saline NaCl ± CaCl2 ± CO2 brines in the brecciated felsite (Qtz-1). According to the quartz-hematite geothermometer the ore depositional temperatures were ~370–330°C (Qtz-2a), whereas the successive quartz veins formed during cooling towards ~295°C. The transport of PGE must have been facilitated by strongly oxidizing chloride complexes of relatively low salinity and moderate acidity.

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Ucurum, Ali, Paul J. Lechler, Greg B. Arehart, and Ferenc Molnar. "Platinum-Group Element, Stable Isotope, and Fluid Inclusion Investigation of the Ultramafic Rock-Hosted Gunes-Sogucak Ni-Cu-Sulfide Mineralization in the Gunes Ophiolite, East-Central Turkey." International Geology Review 49, no. 2 (February 2007): 169–92. http://dx.doi.org/10.2747/0020-6814.49.2.169.

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Chen, Hsin-Yu, Rahul Aggarwal, Robert A. Bok, Michael A. Ohliger, Zi Zhu, Philip Lee, Jeremy W. Gordon, et al. "Hyperpolarized 13C-pyruvate MRI detects real-time metabolic flux in prostate cancer metastases to bone and liver: a clinical feasibility study." Prostate Cancer and Prostatic Diseases 23, no. 2 (November 4, 2019): 269–76. http://dx.doi.org/10.1038/s41391-019-0180-z.

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Abstract Background Hyperpolarized (HP) 13C-pyruvate MRI is a stable-isotope molecular imaging modality that provides real-time assessment of the rate of metabolism through glycolytic pathways in human prostate cancer. Heretofore this imaging modality has been successfully utilized in prostate cancer only in localized disease. This pilot clinical study investigated the feasibility and imaging performance of HP 13C-pyruvate MR metabolic imaging in prostate cancer patients with metastases to the bone and/or viscera. Methods Six patients who had metastatic castration-resistant prostate cancer were recruited. Carbon-13 MR examination were conducted on a clinical 3T MRI following injection of 250 mM hyperpolarized 13C-pyruvate, where pyruvate-to-lactate conversion rate (kPL) was calculated. Paired metastatic tumor biopsy was performed with histopathological and RNA-seq analyses. Results We observed a high rate of glycolytic metabolism in prostate cancer metastases, with a mean kPL value of 0.020 ± 0.006 (s−1) and 0.026 ± 0.000 (s−1) in bone (N = 4) and liver (N = 2) metastases, respectively. Overall, high kPL showed concordance with biopsy-confirmed high-grade prostate cancer including neuroendocrine differentiation in one case. Interval decrease of kPL from 0.026 at baseline to 0.015 (s−1) was observed in a liver metastasis 2 months after the initiation of taxane plus platinum chemotherapy. RNA-seq found higher levels of the lactate dehydrogenase isoform A (Ldha,15.7 ± 0.7) expression relative to the dominant isoform of pyruvate dehydrogenase (Pdha1, 12.8 ± 0.9). Conclusions HP 13C-pyruvate MRI can detect real-time glycolytic metabolism within prostate cancer metastases, and can measure changes in quantitative kPL values following treatment response at early time points. This first feasibility study supports future clinical studies of HP 13C-pyruvate MRI in the setting of advanced prostate cancer.

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Li, Katja, Suzanne Zamany Andersen, Michael Statt, Mattia Saccoccio, Vanessa Jane Bukas, Kevin Krempl, Rokas Sazinas, et al. "Enhancement of Lithium-Mediated Ammonia Synthesis By Addition of Oxygen." ECS Meeting Abstracts MA2022-01, no. 40 (July 7, 2022): 1811. http://dx.doi.org/10.1149/ma2022-01401811mtgabs.

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Ammonia is one of the most produced chemicals worldwide and is currently synthesized by the Haber-Bosch process, which is a thermally catalyzed method that requires high pressures and temperatures. These harsh conditions, in addition to the prerequisite steam reforming process, leads to about 1 % of the annual energy consumption and 1.4 % of the global CO2 emission. One way to mitigate some of the Haber-Bosch process is to produce ammonia electrochemically, utilizing renewable energy sources. The electrochemical synthesis of ammonia faces several big issues. One being the selectivity, since the more facile hydrogen evolution reaction (HER) will always dominate over the nitrogen reduction reaction (NRR), and another issue being the activity, given that the nitrogen triple bond is very stable and therefore hard to split. Hence, most often the reported ammonia contents are in the low ppm regime, which makes it very susceptible to contaminations both from the gas stream (NH3 and NOx impurities) and the system itself (catalyst, cell, chemicals, nitrile gloves, etc.). To avoid misleading results, several protocols have been published on how to correctly perform NRR experiments [1, 2]. One of these confirm that only the Li-mediated ammonia synthesis (LiMeAS) is currently able to produce ammonia electrochemically [3]. The actual mechanism is not fully understood, but it is generally believed that the first step is Li plating from a Li salt containing non-aqueous electrolyte. The very reactive Li will then react with N2 solvated in the electrolyte to form Li3N, which is believed to hydrolyze to ammonia when in contact with a proton source. The currently highest archived faradaic efficiency (FE) is at 69 % at 20 bar N2 pressure when applying an ionic liquid as a proton shuttle [4]. In this work, we achieved up to 79 % FE at 20 bar N2 by the addition of 0.8 mol. % O2 in the reaction atmosphere. The positive effect of O2 is a very counterintuitive observation, since the original work by Tsuneto et al. [5] showed that the use of synthetic air significantly hindered the reaction, as it was postulated that O2 inhibits the reaction due to LiO2 formation and/or leading primarily to the oxygen reduction reaction (ORR). We will present experimental results obtained at 10 and 20 bar with varying O2 contents, which were measured accurately by a mass spectrometer probing the atmosphere just above the electrolyte inside the pressure vessel. By combining experimental observations with theoretical modelling, we conclude that the unexpectedly beneficial role of small O2 concentrations has a positive influences the solid electrolyte interface (SEI), which is of great importance in our system. Additional ex-situ X-Ray diffraction (XRD) and X-Ray photoelectron spectroscopy (XPS) measurements were conducted without exposure to air and moisture, to analyze the SEI layer and deposition after electrochemistry. We believe that this study will not only be beneficial for industrializing the LiMeAS, but will also bring us a step further in understanding the complex mechanism behind this process. [1] S. Z. Andersen et al., "A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements," Nature, vol. 570, pp. 504-508, 2019. [2] H. Iriawan et al., "Methods for nitrogen activation by reduction and oxidation," Nature Reviews Methods Primers, vol. 1, no. 1, pp. 1-26, 2021. [3] J. Choi et al., "Identification and elimination of false positives in electrochemical nitrogen reduction studies," Nature communications, vol. 11, no. 1, pp. 1-10, 2020. [4] B. H. Suryanto et al., "Nitrogen reduction to ammonia at high efficiency and rates based on a phosphonium proton shuttle," Science, vol. 372, no. 6547, pp. 1187-1191, 2021. [5] A. Tsuneto, A. Kudo, and T. Sakata, "Lithium-mediated electrochemical reduction of high pressure N2 to NH3," Journal of Electroanalytical Chemistry, vol. 367, no. 1-2, pp. 183-188, 1994.

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Creech, J. B., J. A. Baker, M. R. Handler, J. P. Lorand, M. Storey, A. N. Wainwright, A. Luguet, F. Moynier, and M. Bizzarro. "Late accretion history of the terrestrial planets inferred from platinum stable isotopes." Geochemical Perspectives Letters, November 2016, 94–104. http://dx.doi.org/10.7185/geochemlet.1710.

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Zhou, Haoyang, Robert B. Trumbull, Ilya V. Veksler, Ilya N. Bindeman, Johannes Glodny, Felix E. D. Kaufmann, and Dieter Rammlmair. "Contamination of the Bushveld Complex (South Africa) magmas by basinal brines: Stable isotopes in phlogopite from the UG2 chromitite." Geology, July 12, 2021. http://dx.doi.org/10.1130/g49173.1.

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There is abundant evidence for significant H2O in evolved melts from the platinum-rich UG2 chromitite and the Merensky Reef of the Bushveld Complex (South Africa), but there is no consensus about the source of H2O. We report triple-oxygen and hydrogen isotope ratios of interstitial, late-magmatic phlogopite from three localities of the UG2 layer. The phlogopite yielded δD values of –43‰ to –23‰, which is >30‰ higher than previously known from Bushveld rocks and far above the mantle values of ~–75‰. The phlogopite triple-oxygen isotope ratios are the first to be reported for Bushveld rocks, with values of Δ′17O0.5305 (17O excess relative to the reference line 0.5305) from –0.069‰ to –0.044‰ (δ18O 5.2‰–6.2‰). The oxygen data support existing models of as much as 30%–40% contamination of mantlederived magmas in the lower to middle crust. However, the high δ values require a second step of contamination, which we attribute to brines from the marine sediments in the Transvaal Basin at the emplacement level.

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"Tandem-accelerator mass-spectrometry measurements of 36 C1, 129 I and osmium isotopes in diverse natural samples." Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences 323, no. 1569 (August 25, 1987): 103–19. http://dx.doi.org/10.1098/rsta.1987.0076.

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Tandem AMS measurements at Rochester in the past few years have mainly involved the radioisotopes 36 Cl and 129 I, and some work on 10 Be, in a variety of terrestrial and extraterrestrial samples. Some m easurem ents have also been m ade on certain stable isotopes of osmium in meteorites and geological samples from impact craters. M easurem ents of 36 Cl have been made in groundwater and surface rocks for dating purposes, in ice and soil samples containing nuclear-weapon testing fallout for tracing water movement, and in meteorites and Antarctic ice for terrestrial and extraterrestrial meteoritic age determination. Also, 10 Be has been measured in a lake sediment, and 36 Cl in Greenland ice, through the period of the Maunder minimum ; 129 I has been measured in hydrological systems, in petroleum and in hydrothermal convection cells in the oceanic crust. Other applications involving measurements of these two radioisotopes include hydrotherm al fluids associated with gold mineralization and the determination of the integrity of possible sites for deep nuclear-waste disposal. Previously, the Rochester tandem was employed to measure 14 C and isotopes of platinum and iridium in natural samples.

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Moore, Christopher R., Mark J. Brooks, Albert C. Goodyear, Terry A. Ferguson, Angelina G. Perrotti, Siddhartha Mitra, Ashlyn M. Listecki, et al. "Sediment Cores from White Pond, South Carolina, contain a Platinum Anomaly, Pyrogenic Carbon Peak, and Coprophilous Spore Decline at 12.8 ka." Scientific Reports 9, no. 1 (October 22, 2019). http://dx.doi.org/10.1038/s41598-019-51552-8.

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Abstract A widespread platinum (Pt) anomaly was recently documented in Greenland ice and 11 North American sedimentary sequences at the onset of the Younger Dryas (YD) event (~12,800 cal yr BP), consistent with the YD Impact Hypothesis. We report high-resolution analyses of a 1-meter section of a lake core from White Pond, South Carolina, USA. After developing a Bayesian age-depth model that brackets the late Pleistocene through early Holocene, we analyzed and quantified the following: (1) Pt and palladium (Pd) abundance, (2) geochemistry of 58 elements, (3) coprophilous spores, (4) sedimentary organic matter (OC and sedaDNA), (5) stable isotopes of C (δ13C) and N (δ15N), (6) soot, (7) aciniform carbon, (8) cryptotephra, (9) mercury (Hg), and (10) magnetic susceptibility. We identified large Pt and Pt/Pd anomalies within a 2-cm section dated to the YD onset (12,785 ± 58 cal yr BP). These anomalies precede a decline in coprophilous spores and correlate with an abrupt peak in soot and C/OC ratios, indicative of large-scale regional biomass burning. We also observed a relatively large excursion in δ15N values, indicating rapid climatic and environmental/hydrological changes at the YD onset. Our results are consistent with the YD Impact Hypothesis and impact-related environmental and ecological changes.

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Khosravifarsani, Meysam, Samia Ait-Mohand, Benoit Paquette, Léon Sanche, and Brigitte Guérin. "In vivo behavior of [64Cu]NOTA-terpyridine platinum, a novel chemo-radio-theranostic agent for imaging, and therapy of colorectal cancer." Frontiers in Medicine 9 (September 23, 2022). http://dx.doi.org/10.3389/fmed.2022.975213.

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To overcome resistance to chemotherapy for colorectal cancer, we propose to validate in vivo a novel terpyridine-platinum (TP) compound radiolabeled with the radio-theranostic isotope 64Cu. In vivo stability, biodistribution, PET imaging, tumor growth delay, toxicity and dosimetry of [64Cu]NOTA-C3-TP were determined. The current experimental studies show that [64Cu]NOTA-C3-TP is stable in vivo, rapidly eliminated by the kidneys and has a promising tumor uptake ranging from 1.8 ± 0.4 to 3.0 ± 0.2 %ID/g over 48 h. [64Cu]NOTA-C3-TP retarded tumor growth by up to 6 ± 2.0 days and improved survival relative to vehicle and non-radioactive [NatCu]NOTA-C3-TP over 17 days of tumor growth observation. This effect was obtained with only 0.4 nmol i.v. injection of [64Cu]NOTA-C3-TP, which delivers 3.4 ± 0.3 Gy tumoral absorbed dose. No evidence of toxicity, by weight loss or mortality was revealed. These findings confirm the high potential of [64Cu]NOTA-TP as a novel radio-theranostic agent.

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Yin, Jie, Yiping Wen, Jing Zeng, Yanyan Zhang, Jiayu Chen, Yanmei Zhang, Tiantian Han, et al. "CDC50A might be a novel biomarker of epithelial ovarian cancer-initiating cells." BMC Cancer 22, no. 1 (August 19, 2022). http://dx.doi.org/10.1186/s12885-022-09953-y.

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Abstract Background The aim of this work was to screen and validate biomarkers of ovarian cancer-initiating cells to detect the mechanisms of recurrence of epithelial ovarian cancer (EOC). Methods Stably labelled the amino acid in side population (SP) cells of epithelial ovarian cancer which were rich in cancer-initiating cells and non-SP cells with isotope in culture and differentially expressed cellular membrane proteins in SP cells were identified through proteomics technology. The new candidate biomarker was screened and validated through RT-PCR and western blot. Both in cell lines and primary EOC, cancer-initiating biofunctions of CDC50A positive cells were validated. Moreover, the characteristics of mesenchymal transition (EMT) was also detected and the correlation between the biomarker and clinical prognosis was observed. Results Through proteomics technology, candidate protein CDC50A was screened, and its significantly differential expression in SP cells was validated. CDC50A-positive cells from cell lines and primary ovarian cancer tissues were validated to show characteristics of cancer-initiating cells both in vitro and in vivo, including sphere-forming, self-renewal, differentiation, tumor metastasis and tumorigenicity in mice. The relationship between CDC50A-positive cells from primary tissues and tumour metastasis was confirmed based on their mesenchymal transition characteristics. Among 16 high-grade ovarian serous cancer patients, a high ratio of CDC50A-positive cells in primary tumours was correlated with a shorter platinum-free interval (p = 0.031, HR 0.260, 95% CI 0.77 ~ 0.885). Conclusion CDC50A could be used to screen ovarian cancer-initiating cells and might be a new target to resolve tumour development in EOC patients.

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Journal articles on the topic 'Platinum stable isotopes'

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