122 research outputs found
IRSL Signals from Maar Lake Sediments Stimulated at Various Temperatures
Optisch stimulierte Lumineszenz (OSL) und infrarot stimulierte Lumineszenz (IRSL) wurden an sieben Feinkorn Proben von Kern JW3 aus dem Trockenmaar Jungfernweiher gemessen. Zwei verschiedene post-IR IRSL Messprotokolle (blaue Detektion) wurden an den polymineralischen Feinkörnern (4–11 μm) angewandt. Diese Protokolle beinhalten eine Stimulation mit IR bei 50°C für bis zu 200 s vor einer weiteren IR Stimulation bei erhöhten Temperaturen bei 225°C für 100 s oder 290°C für 200 s. Die OSL von Quarz sättigt bei Dosen von 260–300 Gy und die De-Werte, die mit IRSL bei 50°C (IR50) erhalten werden, nehmen mit der Tiefe nicht zu. Dies weist darauf hin, dass auch dieses Signal bei ~500 Gy in Sättigung geht. De-Werte des post-IR IRSL Signals bei 225°C (pIRIR225) und 290°C (pIRIR290) nehmen jedoch mit der Tiefe von ~800 Gy bis ~1400 Gy zu, und zeigen ein korrigiertes Minimalalter von ~200 ka für die jüngsten Sedimente an. Die durchschnittlichen im Labor gemessene Fadingraten liegen für IR50 bei 4.09 ± 0.02%/decade und für pIRIR225 bei 2.55 ± 0.14%/decade. Für Probe JWS1 wurde für pIRIR290 ein g-value von 0.52 ± 1.12%/decade gemessen. Sowohl fading korrigierte pIRIR225 als auch unkorrigierte pIRIR290 De-Werte der jüngsten Probe (~16 m unterhalb der heutigen Erdoberfläche) weisen auf ein Alter von ~250 ka für die oberste Probe hin. Für die ältesten Proben, die in ~94 m unterhalb der heutigen Erdoberfläche genommen wurden, wurden Alter von bis zu ~400 ka gemessen.researc
Combining 10Be surface exposure and OSL dating to reconstruct Holocene lake-level fluctuations: a case study at Tangra Yumco (southern Tibet)
Abstract HKT-ISTP 2013
B
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Chronology of Cauvery Delta Sediments from Shallow Subsurface Cores Using Elevated-Temperature Post-IR IRSL Dating of Feldspar
We present the results of luminescence dating of sediments from two cores from the Cauvery Delta in south-east India. Since all natural quartz OSL signals except one sample were in saturation, the elevated temperature post-IR IRSL protocol for K-feldspar was applied to establish a chronology. Internal dose rates of K-feldspar grains were calculated from the measured internal content of potassium, uranium, thorium and rubidium in the bulk of K-feldspar grains using solution ICP-OES and ICP-MS analysis. A substantial scatter in single-aliquot De values was observed which is most probably due to the effect of incomplete bleaching of fluvial sediments before burial. A minimum age model was applied to extract possible depositional ages. The study revealed that except an upper layer of Holocene sediments (< 5m), the majority of the upper ~50m of Cauvery delta sediments were deposited between marine isotope stage MIS-5 and MIS-10 or older. The feldspar luminescence ages also indicate the existence of a period of non deposition or erosion in the upper part of the cores. © 2010 GADAM Centre Institute of Physics, Silesian University of Technology. All rights reserved
Флуориметрическая методика оценки влияния доксорубицина на жизнеспособность лактобактерий
Объектами исследования являются лекарственные препараты "Лактобактерин" и "Доксорубицин". Цель работы заключается в разработке флуориметрической методики оценки влияния доксорубицина на жизнеспособность лактобактерий. В результате исследования разработана флуориметрическая методика оценки влияния доксорубицина на лактобактерии.The object of study are drugs "Lactobacterin" and "Doxorubicin". The purpose of the work is to develop a fluorimetric methodology for assessing the effect of doxorubicin on the viability of lactobacillus. As a result of the study, a fluorimetric method for assessing the effect of doxorubicin on the viability of lactobacillus
Aeolianite and barrier dune construction spanning the last two glacial-interglacial cycles from the southern Cape coast, South Africa
The southern Cape region of South Africa has extensive coastal aeolianites and barrier dunes. Whilst previously reported, limited knowledge of their age has precluded an understanding of their relationship with the climatic and sea-level fluctuations that have taken place during the Late Quaternary. Sedimentological and geomorphological studies combined with an optical dating programme reveal aeolianite development and barrier dune construction spanning at least the last two glacial–interglacial cycles. Aeolianite deposition has occurred on the southern Cape coast at ca 67–80, 88–90, 104–128, 160–189 and >200 ka before the present. Using this and other published data coupled with a better understanding of Late Quaternary sea-level fluctuations and palaeocoastline configurations, it is concluded that these depositional phases appear to be controlled by interglacial and subsequent interstadial sea-level high stands. These marine transgressions and regressions allowed onshore carbonate-rich sediment movement and subsequent aeolian reworking to occur at similar points in the landscape on a number of occasions. The lack of carbonates in more recent dunes (Oxygen Isotope Stages 1/2 and 4/5) is attributed not to leaching but to changes to carbonate production in the sediment source area caused by increased terrigenous material and/or changes in the balance between the warm Agulhas and nutrient-rich Benguela ocean current
Physiologically-based pharmacokinetic modeling of quinidine to establish a CYP3A4, P-gp, and CYP2D6 drug-drug-gene interaction network
The antiarrhythmic agent quinidine is a potent inhibitor of cytochrome P450 (CYP) 2D6 and P-glycoprotein (P-gp) and is therefore recommended for use in clinical drug-drug interaction (DDI) studies. However, as quinidine is also a substrate of CYP3A4 and P-gp, it is susceptible to DDIs involving these proteins. Physiologically-based pharmacokinetic (PBPK) modeling can help to mechanistically assess the absorption, distribution, metabolism, and excretion processes of a drug and has proven its usefulness in predicting even complex interaction scenarios. The objectives of the presented work were to develop a PBPK model of quinidine and to integrate the model into a comprehensive drug-drug(-gene) interaction (DD(G)I) network with a diverse set of CYP3A4 and P-gp perpetrators as well as CYP2D6 and P-gp victims. The quinidine parent-metabolite model including 3-hydroxyquinidine was developed using pharmacokinetic profiles from clinical studies after intravenous and oral administration covering a broad dosing range (0.1-600 mg). The model covers efflux transport via P-gp and metabolic transformation to either 3-hydroxyquinidine or unspecified metabolites via CYP3A4. The 3-hydroxyquinidine model includes further metabolism by CYP3A4 as well as an unspecific hepatic clearance. Model performance was assessed graphically and quantitatively with greater than 90% of predicted pharmacokinetic parameters within two-fold of corresponding observed values. The model was successfully used to simulate various DD(G)I scenarios with greater than 90% of predicted DD(G)I pharmacokinetic parameter ratios within two-fold prediction success limits. The presented network will be provided to the research community and can be extended to include further perpetrators, victims, and targets, to support investigations of DD(G)Is.Horizon 2020 (H2020)Personalised Therapeutic
Methods for measuring gas emissions from naturally ventilated livestock buildings: Developments over the last decade and perspectives for improvement
[EN] The objectives of this paper are: 1) to give an overview of the development of methods for measuring emission rates from naturally ventilated livestock buildings over the last decade, 2) to identify and evaluate strengths and weaknesses, 3) to summarise and conclude the current state-of-art of available measurement concepts and their perspectives for improvement. The methods reviewed include determination of concentration and air exchange rate separately, tracer gas ratio, passive flux samplers, flux chambers, and combined downwind measurement and dispersion modelling. It is concluded that passive flux samplers, flux chambers and combined measurement and dispersion modelling are useful, but for limited fields of application only and require further development and validation against reference methods. The most robust method to investigate emission rates available at this stage is the tracer gas ratio method, but improvements are required. They include more detailed estimates of CO2 release rates (when using CO2 as a tracer) and research into optimising dosing performance of tracer gas release systems. The reliability of tracer gas ratio methods applied in buildings with large ventilation openings needs to be improved by a more profound understanding of tracer-pollutant ratios and their spatial variability, and the development of improved sampling methods for concentration ratios. There is a need for a field reference method against which other methods can be evaluated. None of the diicussed measurement methods can be marked as a solid reference for all conditions; tracer gas ratio methods are the most likely candidate but need further improvement. (C) 2012 IAgrE. Published by Elsevier Ltd. All rights reserved.The contribution to this paper of N. Ogink and J. Mosquera was financially supported by the Netherlands Ministry of Infrastructure and Environment.Ogink, NWM.; Mosquera, J.; Calvet Sanz, S.; Zhang, G. (2013). Methods for measuring gas emissions from naturally ventilated livestock buildings: Developments over the last decade and perspectives for improvement. Biosystems Engineering. 116(3):297-308. https://doi.org/10.1016/j.biosystemseng.2012.10.005S297308116
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