Background Levels and Radiation Dose Yield of o-Tyrosine in Chicken Meat

1991 ◽  
Vol 54 (12) ◽  
pp. 935-938 ◽  
Author(s):  
NOEMI CHUAQUI-OFFERMANNS ◽  
TOM MCDOUGALL
Keyword(s):  
Radiation Dose ◽  
Dose Response ◽  
Response Curve ◽  
Dose Range ◽  
Background Level ◽  
Chicken Meat ◽  
Dose Response Curve ◽  
Poultry Meat ◽  
Wet Weight ◽  
The Mean

The measurement of o-tyrosine levels in poultry meat is a potential method for postirradiation dosimetry of poultry. The validity of using o-tyrosine for this purpose has not yet been established. As part of the validation process, the o-tyrosine content in unirradiated chicken meat, the radiation dose response curve, and the effects of postirradiation storage on o-tyrosine levels are examined. In 18 individual samples, the mean background level of o-tyrosine was 0.18 ± 0.11 ppm (wet weight, 70% moisture), and the most frequent background level (60% of the cases) was between 0.05 and 0.15 ppm (wet weight, 70% moisture). In pooled samples of 10 chickens, the mean background level was 0.12 ± 0.03 ppm (wet weight, 70% moisture). The levels were not significantly affected by storage at 5°C (7 d) or by freezing the sample. The radiation dose response curve was linear within the dose range studied (0 to 10 kGy), with a slope of 0.127 ± 0.003 ppm (wet weight)/kGy. Although there was some variation in the intercept (0.132 ± 0.013), the slope was the same in all samples tested. Postirradiation storage at either 4 or 8°C until spoilage did not affect the levels of o-tyrosine. These data indicate that o-tyrosine level may be useful for determining the absorbed dose in chicken meat gamma-irradiated to doses greater than 0.6 kGy. Further validation studies are continuing.

OVARIAN ASCORBIC ACID DEPLETION TEST FOR LUTEINIZING HORMONE

1967 ◽  
Vol 56 (4) ◽  
pp. 619-625 ◽  
Author(s):  
Hans Jacob Koed ◽  
Christian Hamburger
Keyword(s):  
Ascorbic Acid ◽  
Luteinizing Hormone ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Origin ◽  
Response Curves ◽  
Significant Difference ◽  
The Mean ◽  
Different Levels

ABSTRACT Comparison of the dose-response curves for LH of ovine origin (NIH-LH-S8) and of human origin (IRP-HMG-2) using the OAAD test showed a small, though statistically significant difference, the dose-response curve for LH of human origin being a little flatter. Two standard curves for ovine LH obtained with 14 months' interval, were parallel but at different levels of ovarian ascorbic acid. When the mean ascorbic acid depletions were calculated as percentages of the control levels, the two curves for NIH-LH-S8 were identical. The use of standards of human origin in the OAAD test for LH activity of human preparations is recommended.

Study of dosimetric characteristics of a commercial optically stimulated luminescence system

2017 ◽  
Vol 16 (4) ◽  
pp. 461-475 ◽  
Author(s):  
Gourav K. Jain ◽  
Arun Chougule ◽  
Ananth Kaliyamoorthy ◽  
Suresh K. Akula
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Light Exposure ◽  
Dose Range ◽  
Optically Stimulated Luminescence ◽  
Dose Response Curve ◽  
Field Size ◽  
In Vivo Dosimetry ◽  
Detector Response

AbstractBackgroundOptically stimulated luminescence dosimeters (OSLDs) have a number of advantages in radiation dosimetry making them an excellent dosimeter for in vivo dosimetry. The study aimed to study the dosimetric characteristics of a commercial optically stimulated luminescence (OSL) system by Landauer Inc., before using it for routine clinical practice for in vivo dosimetry in radiotherapy. Further, this study also aimed to investigate the cause of variability found in the literature in a few dosimetric parameters of carbon-doped aluminium oxide (Al2O3:C).Materials and methodsThe commercial OSLD system uses Al2O3:C nanoDotTM as an active radiation detector and InLightTM microStar® as a readout assembly. Inter-detector response, energy, dose rate, field size and depth dependency of the detector response were evaluated for all available clinical range of photon beam energies in radiotherapy.ResultsInter-detector variation in OSLD response was found within 3·44%. After single light exposure for the OSL readout, detector reading decreased by 0·29% per reading. The dose linearity was investigated between dose range 50–400 cGy. The dose response curve was found to be linear until 250 cGy, after this dose, the dose response curve was found to be supra-linear in nature. OSLD response was found to be energy independent for Co60 to 10 MV photon energies.ConclusionsThe cause of variability found in the literature for some dosimetric characteristics of Al2O3:C is due to the difference in general geometry, construction of dosimeter, geometric condition of irradiation, phantom material and geometry, beam energy. In addition, the irradiation history of detector used and difference in readout methodologies had varying degree of uncertainties in measurements. However, the large surface area of the detector placed in the phantom with sufficient build-up and backscatter irradiated perpendicularly to incident radiation in Co60 beam is a good method of choice for the calibration of a dosimeter. Understanding the OSLD response with all dosimetric parameters may help us in estimation of accurate dose delivered to patient during radiotherapy treatment.

The Radiation Dose-Response Curve and Bacterial Mutations

Science ◽  
1951 ◽  
Vol 114 (2965) ◽  
pp. 436-437 ◽  
Author(s):  
W. E. Jordan ◽  
R. B. Mefferd ◽  
O. Wyss
Keyword(s):  
Radiation Dose ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Bacterial Mutations

Polyethylene glycol-conjugated superoxide dismutase in focal cerebral ischemia-reperfusion

1993 ◽  
Vol 265 (1) ◽  
pp. H252-H256 ◽  
Author(s):  
Y. Y. He ◽  
C. Y. Hsu ◽  
A. M. Ezrin ◽  
M. S. Miller
Keyword(s):  
Superoxide Dismutase ◽  
Polyethylene Glycol ◽  
Cerebral Ischemia ◽  
Infarct Size ◽  
Dose Response ◽  
Response Curve ◽  
Focal Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Dose Range ◽  
Dose Response Curve

Generation of free radicals during reperfusion after organ ischemia has been implicated in the pathogenesis of ischemic injury. We have previously shown that a combination of intravenous polyethylene glycol-conjugated superoxide dismutase (PEG-SOD) and catalase (PEG-CAT), at a dose of 10,000 U/kg each, is effective in reducing infarct size in a focal cerebral ischemia model in the rat. It is not clear whether PEG-SOD alone is sufficient to reduce ischemic brain injury. In this study we determined the therapeutic efficacy of PEG-SOD and its dose-response curve. In a range of 1,000-30,000 U/kg, PEG-SOD exhibited a U-shaped dose-response curve. Only 10,000 U/kg significantly reduced infarct size [control 121 +/- 12 mm3 (mean +/- SE), n = 35; PEG-SOD 95 +/- 10 mm3, n = 36, P < 0.05]. PEG-SOD at the doses tested did not have significant acute hemodynamic effects but had a tendency to improve postischemic hypotension. This beneficial effect of PEG-SOD on blood pressure did not appear to fully account for the treatment effect of PEG-SOD on infarct size. The narrow therapeutic dose range of PEG-SOD in this study and similar findings of SOD in other investigations may contribute to the inconsistent protective effects of SOD preparations in ischemia-reperfusion injury in the literature.

SU-FF-T-366: Radiation Dose Response Curve of Human Cerebral Cortex Measured with [F-18]-FDG and [O-15]-H2O PET Imaging

2005 ◽  
Vol 32 (6Part12) ◽  
pp. 2035-2035
Author(s):  
S Zhou ◽  
C Hahn ◽  
T Shafman ◽  
J Kirkpatrick ◽  
A Tisch ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Radiation Dose ◽  
Dose Response ◽  
Pet Imaging ◽  
Response Curve ◽  
Dose Response Curve ◽  
Human Cerebral Cortex ◽  
O 15

Cytotoxicity and influence on radiation dose response curve of cis-diamminedichloroplatinum II (cis-DDP)

1979 ◽  
Vol 5 (8) ◽  
pp. 1411-1415 ◽  
Author(s):  
Anantha K. Murthy ◽  
Arthur H. Rossof ◽  
Kenneth M. Anderson ◽  
Frank R. Hendrickson
Keyword(s):  
Radiation Dose ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve

scholarly journals Assessing the maximum limit of SAR-OSL dating using quartz of different grain sizes

2018 ◽  
Vol 45 (1) ◽  
pp. 146-159 ◽  
Author(s):  
Valentina Anechitei-Deacu ◽  
Alida Timar-Gabor ◽  
Daniela Constantin ◽  
Oana Trandafir-Antohi ◽  
Laura Del Valle ◽  
...  
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Dose Range ◽  
Osl Dating ◽  
Dose Response Curve ◽  
High Dose ◽  
Response Curves ◽  
Grain Sizes ◽  
Coarse Grains ◽  
Dose Response Curves

Abstract SAR-OSL dating studies of Romanian, Serbian and Chinese loess using fine and coarse quartz have previously resulted in a series of controversial issues. We extend here the investigations using fine (4–11 μm) and different coarse quartz (>63 μm) grains extracted from aeolianites from a site on Eivissa Island (southwestern Mediterranean). Aeolianites were chosen since they contain quartz from a different geological context and have significantly lower environmental dose rates. The dose response curves of the OSL signals for fine and coarse quartz are similar to those for loess and are also represented by the sum of two saturating exponential functions. For doses up to ~200 Gy, the dose response curves of fine and coarse grains from aeolianites can be superimposed and the ages obtained for the different grain sizes are in agreement up to ~250 ka, increasing our confidence in the accuracy of the ages obtained for samples with such doses, irrespective of the magnitude of the environmental dose rate. Particularly for the fine quartz fraction, a mismatch between the SAR dose response curve and the dose response curve obtained when doses are added to the natural is reported, indicating that the application of the SAR protocol in the high dose range is problematic. This dose dependent deviation is much less pronounced for coarse grains. Thus, it seems reasonable to infer that the dose response curves for the coarse grains, although saturating earlier can be regarded as more reliable for equivalent dose calculation than those for the fine grains.

Sign in / Sign up

Export Citation Format

Share Document