scholarly journals Combined Size and Density Fractionation of Soils for Investigations of Organo-Mineral Interactions

10.3791/58927 ◽  
2019 ◽  
Author(s):  
Fanny Viret ◽  
Stephanie Grand
Keyword(s):  
Density Fractionation

scholarly journals A New Radiocarbon Pretreatment Method for Molluscan Shell Using Density Fractionation of Carbonates in Bromoform

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1301-1311 ◽  
Author(s):  
Christopher M Russo ◽  
Jennifer A Tripp ◽  
Katerina Douka ◽  
Thomas F G Higham
Keyword(s):  
Radiocarbon Dating ◽  
Separation Technique ◽  
Archaeological Sites ◽  
Density Fractionation ◽  
Pretreatment Method ◽  
Density Separation ◽  
Molluscan Shell ◽  
Archaeological Artifacts ◽  
Organic Remains

Coastal archaeological sites that lack organic remains for radiocarbon dating are often abundant sources of molluscan shells. As a substitute for materials such as bone and charcoal, shells can be analyzed with 14C dating to determine a site's age. Despite their being convenient, non-mobile archaeological artifacts, molluscan shells are plagued by several issues, including carbonate remodeling, in which aragonite in shells is converted to calcite as predicted by thermodynamics. We present here a carbonate density separation technique that addresses the issue of carbonate remodeling. Using a density fractionation with bromoform, aragonite concentrations are enriched in shells that have undergone significant remodeling. The technique has been applied to archaeological shells and has returned dates that are younger than those previously determined for the same shells.

scholarly journals Identification of heat-shock protein 90 beta in Japanese encephalitis virus-induced secretion proteins

2011 ◽  
Vol 92 (12) ◽  
pp. 2803-2809 ◽  
Author(s):  
Chun-Yu Hung ◽  
Meng-Chieh Tsai ◽  
Yi-Ping Wu ◽  
Robert Y. L. Wang
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Molecular Chaperones ◽  
Heat Shock Protein 90 ◽  
Rna Replication ◽  
Hsp90 Inhibitor ◽  
Encephalitis Virus ◽  
Virus Infectivity ◽  
Density Fractionation ◽  
Virus Particles

Five host cellular proteins were identified in the secretion medium from Japanese encephalitis virus (JEV)-infected baby hamster kidney-21 (BHK-21) cells, including three molecular chaperones: Hsp70, GRP78 and Hsp90. Hsp90 isoforms were characterized further. Hsp90α was observed to be retained inside the nuclei, whereas Hsp90β associated with virus particles during assembly and was released into the secretion medium upon JEV infection. The association of Hsp90β and viral E protein was demonstrated by using sucrose-density fractionation and Western blot analysis. Moreover, JEV viral RNA replication was not affected by treatment with geldanamycin, an Hsp90 inhibitor, but impaired virus infectivity that was determined by a plaque-forming assay. Our results show that Hsp90β, not Hsp90α, is present in the JEV-induced secretion medium and is required for JEV infectivity in BHK-21 cells.

scholarly journals Density fractions versus size separates: does physical fractionation isolate functional soil compartments?

2012 ◽  
Vol 9 (12) ◽  
pp. 5181-5197 ◽  
Author(s):  
C. Moni ◽  
D. Derrien ◽  
P.-J. Hatton ◽  
B. Zeller ◽  
M. Kleber
Keyword(s):  
Organic Matter ◽  
Mineral Soil ◽  
European Beech ◽  
Nitrogen Dynamics ◽  
Protective Mechanism ◽  
Density Fractionation ◽  
Adsorbed State ◽  
Density Fractions ◽  
Physical Fractionation ◽  
Comprehensive Picture

Abstract. Physical fractionation is a widely used methodology to study soil organic matter (SOM) dynamics, but concerns have been raised that the available fractionation methods do not well describe functional SOM pools. In this study we explore whether physical fractionation techniques isolate soil compartments in a meaningful and functionally relevant way for the investigation of litter-derived nitrogen dynamics at the decadal timescale. We do so by performing aggregate density fractionation (ADF) and particle size-density fractionation (PSDF) on mineral soil samples from two European beech forests a decade after application of 15N labelled litter. Both density and size-based fractionation methods suggested that litter-derived nitrogen became increasingly associated with the mineral phase as decomposition progressed, within aggregates and onto mineral surfaces. However, scientists investigating specific aspects of litter-derived nitrogen dynamics are pointed towards ADF when adsorption and aggregation processes are of interest, whereas PSDF is the superior tool to research the fate of particulate organic matter (POM). Some methodological caveats were observed mainly for the PSDF procedure, the most important one being that fine fractions isolated after sonication can not be linked to any defined decomposition pathway or protective mechanism. This also implies that historical assumptions about the "adsorbed" state of carbon associated with fine fractions need to be re-evaluated. Finally, this work demonstrates that establishing a comprehensive picture of whole soil OM dynamics requires a combination of both methodologies and we offer a suggestion for an efficient combination of the density and size-based approaches.

scholarly journals Differentiating Bone Osteonal Turnover Rates By Density Fractionation; Validation Using the Bomb 14C Atmospheric Pulse

Radiocarbon ◽  
2004 ◽  
Vol 46 (2) ◽  
pp. 853-861 ◽  
Author(s):  
Ji Young Shin ◽  
Tamsin O'Connell ◽  
Stuart Black ◽  
Robert Hedges
Keyword(s):  
Post Mortem ◽  
Density Fractionation ◽  
Turnover Rates ◽  
Fractionation Method ◽  
Older Populations ◽  
Microbial Attack

The density (BSG) of bone increases, at the osteon scale, during lifetime aging within the bone. In addition, post-mortem diagenetic change due to microbial attack produces denser bioapatite. Thus, fractionation of finely powdered bone on the basis of density should not only enable younger and older populations of osteons to be separated but also make it possible to separate out a less diagenetically altered component. We show that the density fractionation method can be used as a tool to investigate the isotopic history within an individual's lifetime, both in recent and archaeological contexts, and we use the bomb 14C atmospheric pulse for validating the method.

scholarly journals An investigation of the distribution of phosphorus between free and mineral associated soil organic matter, using density fractionation

2017 ◽  
Vol 427 (1-2) ◽  
pp. 139-148 ◽  
Author(s):  
Jessica L. Adams ◽  
Edward Tipping ◽  
Sarah A. Thacker ◽  
John N. Quinton
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Density Fractionation
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