Találati lista | Tudóstér

001-es BibID:	BIBFORM116077
035-os BibID:	(Scopus)85175964697
Első szerző:	Kiss Gabriella Ilona (vegyész)
Cím:	Comparison of different preparation methods for oxygen isotope determination of phosphate in mammal tooth enamel / Gabriella Ilona Kiss, Péter Szabó, Marianna Túri, István Futó, János Kovács, László Palcsu
Dátum:	2023
ISSN:	1788-2281 1789-3348
Megjegyzések:	We tested several sample pre-Treatment protocols for the study of oxygen isotope ratios in the phosphate phase of mammalian enamel of ten different fossil samples. We investigated the effect of different pre-Treatment methods and the duration of the hydrogen fluoride treatment on enamel samples from skeletal phosphate with known ?18O values. The samples had been measured previously, so we could compare the ratios measured in our laboratory with the previous values to choose the best chemical preparation procedure. Four pre-soaking methods and two different time intervals of 2 mol dm-3 hydrogen fluoride treatment were compared during our experiments. In our experimental conditions, the distilled water wash and the 6 h of soaking in hydrogen fluoride gave the closest results to the expected ?-values. The steps of the tested preparation processes were repeated at least three times on each sample, so the reproducibility of the process could be also investigated.
Tárgyszavak:	Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény hazai lapban folyóiratcikk bioapatite fossil mammal teeth oxygen isotopes paleoclimate reconstruction phosphate pre-Treatment protocols
Megjelenés:	Central European Geology. - 65 : 2 (2023), p. 144-157. -
További szerzők:	Szabó Péter Túri Marianna (1988-) (geográfus-geoinformatikus) Futó István (fizikus) Kovács János (1950-) (agrármérnök) Palcsu László (1975-) (fizikus)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM083343
035-os BibID:	(cikkazonosító)8626
Első szerző:	Kiss Gabriella Ilona (vegyész)
Cím:	Oxygen isotope ratio measurements on bioapatite samples prepared from mammal tissues: method development at ICER Centre / Kiss Gabriella, Túri Marianna, Futó István, Kovács János, Szabó Péter, Palcsu László
Dátum:	2019
ISSN:	1029-7006 1607-7962
Megjegyzések:	To get more information about the changes of the palaeoclimatic conditions on Earth, many method can be used, especially, stable isotope measurements on different elements. Beside the stable isotope analysis of hydrogen, carbon and nitrogen, which can provide interesting facts about the environment and diet in case of modern samples, the stable isotope measurements of other elements like oxygen can complete these informations with other data, for example the environmental water temperature, in case of older samples. During this work we compared some different preparation methods for oxygen isotope analysis of biological apatites. To carry out these measurements, well preserved tissues should be used for the chemical processes, for example scales, teeth or bone pieces/powder. During our experiments the effect of the different precleaning methods (a. distilled water; b. 1 M calcium acetate?acetic acid buffer solution; c. 10 % hydrogen peroxide and 1 M calcium acetate?acetic acid buffer solution; d. 12 % sodium hypochlorite and 1 M calcium acetate?acetic acid buffer solution) and the duration of the hydrogen-fluoride treatment (6, 12, and 24 hours) were examined. The preparation methods were tested on enamel samples (mainly Stephanorphinus sp.), with a well known and previously published d18Ophosphate vs. VSMOW values between +11 ? and +20 ? (Szabó et al., 2017). The phosphate d18O ratio of the bioapatite was measured in silver phosphate precipitation form. The measurements were carried out on a Thermo Finnigan Delta plus XP isotope ratio mass spectrometer with a TC/EA high temperature elemental analyzer. Through these investigations the relation between the shift in the measured isotope ratios and the precleaning or preparation processes can be brightened. With these comparisons and investigations, our goal is to develop an accurate and precise method for the oxygen isotope analysis of bioapatite at the ICER Centre
Tárgyszavak:	Természettudományok Kémiai tudományok idézhető absztrakt folyóiratcikk
Megjelenés:	Geophysical Research Abstracts. - 21 (2019), p. 8626. -
További szerzők:	Túri Marianna (1988-) (geográfus-geoinformatikus) Futó István (fizikus) Kovács János Szabó Péter Palcsu László (1975-) (fizikus)
Pályázati támogatás:	GINOP-2.3.2-15-2016-00009 GINOP
Internet cím:	Szerző által megadott URL Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM083342
Első szerző:	Palcsu László (fizikus)
Cím:	Local temperature calibration of carbonate-water oxygen isotope fractionation and clumped isotopes (?47) in a karstic freshwater limestone environment / László Palcsu, Marianna Túri, István Futó, János Kovács, Péter Szabó, Judit Orsovszki, Marjan Temovski, László Rinyu
Dátum:	2019
ISSN:	1029-7006 1607-7962
Megjegyzések:	Oxygen isotope ratios of carbonates are widely used as palaeoclimate indicators since isotope fractionation between the carbonate and the water phase is temperature dependent. The available empirical equationsare reliable for deposits which are precipitated under isotopic equilibrium. However, in many cases, precipitation of abiotic carbonate sediments (flowstones, freshwater limestones, travertines, tufas, etc.) can occur with fast CO2 degassing, which tends to result in a kinetic fractionation of isotope compositions. In karst environments, freshwater limestone is precipitated from cold spring waters as the creek is flowing and the dissolved CO2 is released from the water. This process creates tufa deposits. Our aim is to investigate the suitability of the tufa deposits as a palaeoclimate archive, even if kinetic fractionation plays a significant role during carbonate formation. In Mecsek Mts, Hungary, tufa deposits can be found in karst valleys. We have chosen a karst spring of constant annual temperature of 10.3 ?C. As the water is flowing away from the spring, it is heated up or cooled down by the ambient air, so the annual temperature variation is increasing with the distance from the spring. In 2015, glass plates, as well as temperature loggers, were placed in the water downstream from the spring along with a 200 m long section, so that carbonate could be precipitated onto the glass surface. In 3-4 weeks the glass plates are replaced. Daily average temperatures of the water vary between 0 and 25.6 ?C, while temperatures averaged to the sampling periods vary between 0.8 and 20.1 ?C. The first ? 18Ocarb and clumped isotope results show a significant temperature dependence, although the equations are shifted from those that are reliable to equilibrium circumstances. However, both ? 18Ocarb-T and ?47-T relationships seem to be significant and therefore applicable to the old tufa layers for reconstructing palaeotemperatures.
Tárgyszavak:	Természettudományok Környezettudományok idézhető absztrakt folyóiratcikk
Megjelenés:	Geophysical Research Abstracts. - 21 (2019), p. 8493. -
További szerzők:	Túri Marianna (1988-) (geográfus-geoinformatikus) Futó István (fizikus) Kovács János Szabó Péter Orsovszki Judit Temovski, Marjan Rinyu László (fizikus)
Pályázati támogatás:	GINOP-2.3.2-15-2016-00009 GINOP
Internet cím:	Szerző által megadott URL Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: