Review Article : Feudalism or Absolute Monarchism?

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68809/2/10.1177_009770049001600304.pd

Progress in Radiocarbon Dating with the Chalk River MP Tandem Accelerator

From the 10th International Radiocarbon Conference held in Bern, Switzerland and Heidelberg, Germany, August 19-26, 1979.The evolution of a tandem accelerator 14C dating system at Chalk River is recounted. Background problems and sources of instability are discussed and solutions are described. Details of sample chemistry and source preparation are presented.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Recent 14C Measurements with the Chalk River Tandem Accelerator

From the 11th International Radiocarbon Conference held in Seattle, Washington, June 20-26, 1982.The Chalk River Tandem Accelerator Mass Spectrometry System has reached a state of reliable measurement of 14C using 2 to 5mg elemental carbon prepared by Mg reduction of CO2. For two comparisons of a near-modern unknown with the NBS oxalic acid standard we obtain a total error of ∼ +/- 4.5%, consisting of a random system error of about +/- 3.5% combined with the statistical counting error. Measurements have been made on 70 samples in 30 days of running time during the past year. Samples included deep rock carbonates, cosmogenic 14C in meteorites, charcoal from earthquake fault zones, collagen of bone artifacts and fossil beetle-fragments.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Histological and biochemical analysis of DNA damage after BNCT in rat model

Abstract To understand the mechanism of tumor cell death induced by boron neutron capture therapy (BNCT) and to optimize BNCT condition, we used rat tumor graft models and histological and biochemical analyses were carried out focusing on DNA damage response. Rat lymphosarcoma cells were grafted subcutaneously into male Wister rats. The rats with developed tumors were then treated with neutron beam irradiation 45min after injection of 330mg/kg bodyweight boronophenylalanine (10BPA) (+BPA) or saline control (–BPA). BNCT was carried out in the National Nuclear Center of the Republic of Kazakhstan (neutron flux: 1×109nvt/s, fluence: 6×1011nvt) with the presence of background γ-irradiation of 33Gy. 6 and 20h after BNCT treatment, tumors were resected, fixed and subjected to immunohistochemistry and biochemical analyses. Immunostaining of nuclei showed that double strand break (DSB) marker gamma H2AX staining was high in 20h/+BPA sample but not in 20h/–BPA samples. Poly(ADP-ribose), DSB and single strand break markers of DNA, also demonstrated this tendency. These two markers were observed at low levels in unirradiated tissues or 6h after BNCT either under −BPA and +BPA conditions. HMGB1 level increased in 6h/+BPA but not in 6h/−BPA or 20h/+BPA samples. The persistent staining of γH2AX and poly(ADP-ribose) in +BPA group suggests accumulated DSB damage after BNCT. The early HMGB1 upregulation and γH2AX and poly(ADP-ribose) observed later might be the markers for monitoring the DNA damage induced by BNCT