Radiological Control of Gold Octahedral and Prism Nanoparticles

2007 ◽  
Vol 1056 ◽  
Author(s):  
Tina M. Nenoff ◽  
Jason C. Jones ◽  
Paula P. Provencio ◽  
Donald T. Berry
Keyword(s):  
Dose Rate ◽  
High Dose Rate ◽  
Pure Gold ◽  
High Dose ◽  
Visible Absorption ◽  
Dose Rates ◽  
Radiation Induced ◽  
Radiological Control ◽  
Uv Visible ◽  
Short Time

ABSTRACTWe report on a fundamental morphology growth of gold-based nanoparticles by solution radiolysis. Radiolysis of pure gold-polymer solutions of different dose rates and aging time is examined. A detailed description will be presented of the experimentation, testing and analysis. In particular, we will present data on the formation of gold nano-octahedra and -prism particles. The γ-irradiations were carried out with a 60Co source of 1.345 × 105 Ci (Sandia National Laboratories Gamma Irradiation Facility (GIF). Nanoparticle characterization techniques included are UV-vis and TEM. Similar to what has been seen in earlier silver nanoparticle studies, dose rate dictates the size of nanoparticles formed. At high dose rate, all reducing species are produced and scavenged within a short time, and then coalesce into separate nanoparticles. At low dose rate, the coalescence process is faster than the production rate of the reducing radicals. The reduction of radicals occurs mainly on clusters already formed. The differences in the morphologies result from a combination of dose rate, aging and lack of radical scavengers (e.g. isopropyl alcohol), resulting in either gold nano-spheres, octahedral or prism nanoparticles. The progressive evolution with dose rate of the UV-visible absorption spectra of radiation-induced metal clusters is discussed.

A Positive-Ion Reaction Mechanism for the Radiation Induced Oxidation of Carbon Monoxide in the High Dose Rate Radiolysis of CO–O2 Mixtures

1972 ◽  
Vol 50 (21) ◽  
pp. 3508-3514 ◽  
Author(s):  
C. Willis ◽  
A. W. Boyd ◽  
P. E. Bindner
Keyword(s):  
Dose Rate ◽  
Low Dose ◽  
High Dose Rate ◽  
High Dose ◽  
Total Oxygen ◽  
Dose Rates ◽  
Electron Scavenger ◽  
Radiation Induced ◽  
A Chain ◽  
Positive Ion

Carbon dioxide and ozone yields have been measured in the irradiation of CO–O2 mixtures with single pulses of electrons. The yields of CO2 at 2 × 1027 ev g−1 s−1 are large G(CO2) = 15 ± 1 from 20–60% O2. These decrease by ∼50% at 1028 eV g−1 s−1. Although the results are somewhat irreproducible the addition of c-C4F8, an electron scavenger, increases these CO2 yields at both dose rates by up to a factor of 15. They are reduced to G(CO2) < 2 by the addition of positive ion scavengers. These results are consistent with a chain reaction similar to that proposed for low dose rate studies involving [Formula: see text], [Formula: see text], and [Formula: see text] as chain carriers.The ozone yields are consistent with a total oxygen atom yield of G(O) = 1.4 in pure CO from neutral processes.

scholarly journals Fractionated versus single-dose total body irradiation at low and high dose rates to condition canine littermates for DLA-identical marrow grafts

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3384-3389 ◽  
Author(s):  
R Storb ◽  
RF Raff ◽  
FR Appelbaum ◽  
HJ Deeg ◽  
TC Graham ◽  
...  
Keyword(s):  
Dna Repair ◽  
Single Dose ◽  
Dose Rate ◽  
Total Body Irradiation ◽  
High Dose Rate ◽  
Lymphoid Cells ◽  
High Dose ◽  
Dose Rates ◽  
Total Body ◽  
Allogeneic Marrow

Abstract We explored in dogs the immunosuppressive properties of 450 cGy total body irradiation (TBI) delivered from two opposing 60Co sources, as assessed by the criterion of successful engraftment of allogeneic genotypically DLA-identical littermate marrow. Two questions were asked in this study. Firstly, does dose rate affect the immunosuppressive effect of TBI when administered in a single dose? Secondly, does fractionation alter the immunosuppression of TBI when delivered at a very fast dose rate? Dose rates studied included 7 and 70 cGy/min, and fractionation involved four fractions of 112.5 cGy each, with 6-hour minimum interfraction intervals. Six of 7 dogs receiving 450 cGy single- dose TBI at 70 cGy/min showed sustained engraftment of the allogeneic marrow, compared with 1 of 7 dogs receiving single-dose TBI at 7 cGy/min (P = .01). Fractionated TBI at 70 cGy/min resulted in sustained allogeneic engraftment in 3 of 10 dogs, a result that was statistically significantly worse than that with single-dose TBI at 70 cGy/min (P = .03) and not statistically different (P = .24) from that with fractionated TBI delivered at 7 cGy/min (0 of 5 dogs engrafted). A single dose of 450 cGy of TBI delivered at a rate of 70 cGy/min is significantly more immunosuppressive than the same total dose delivered at 7 cGy/min. Fractionated TBI at 70 cGy/min is significantly less immunosuppressive than single-dose TBI at 70 cGy/min and not significantly different from fractionated TBI administered at 7 cGy/min. Results are consistent with the notion that significant DNA repair in lymphoid cells is possible during interfraction intervals at the relatively high dose rate of 70 cGy/min.

Electron and Beta Dose Rates of UO2 Pellet and Fuel Rod

2013 ◽  
Author(s):  
Guoqing Zhang ◽  
Xuexin Wang ◽  
Jiangang Zhang ◽  
Dajie Zhuang ◽  
Chaoduan Li ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Dose Rate ◽  
Radiation Protection ◽  
High Dose Rate ◽  
High Dose ◽  
Electron Dose ◽  
Dose Rates ◽  
Fuel Rod ◽  
Calculation Results ◽  
Beta Dose

The isotopes of uranium and their daughter nuclides inside the UO2 pellet emit mono-energetic electrons and beta rays, which generate rather high dose rate near the UO2 pellet and could cause exposure to workers. In this work calculations of electron dose rates have been carried out with Monte Carlo codes, MCNPX and Geant4, for a UO2 pellet and a fuel rod. Comparisons between calculations and measurements have been carried out to verify the calculation results. The results could be used to estimate the dose produced by electrons and beta rays, which could be used to make optimization for radiation protection purpose.

Radiation-induced failures and degradation of wireless real-time dosimeter under high-dose-rate irradiation

2010 ◽  
Author(s):  
K. Tsuchiya ◽  
K. Kuroki ◽  
N. Akiba ◽  
K. Kurosawa ◽  
T. Matsumoto ◽  
...  
Keyword(s):  
Dose Rate ◽  
Real Time ◽  
High Dose Rate ◽  
High Dose ◽  
Radiation Induced

scholarly journals Assessing patient characteristics and radiation-induced non-targeted effects in vivo for high dose-rate (HDR) brachytherapy

2015 ◽  
Vol 91 (10) ◽  
pp. 786-794 ◽  
Author(s):  
Christine Pinho ◽  
Emilia Timotin ◽  
Raimond Wong ◽  
Ranjan K. Sur ◽  
Joseph E. Hayward ◽  
...  
Keyword(s):  
Dose Rate ◽  
Patient Characteristics ◽  
High Dose Rate ◽  
High Dose ◽  
Hdr Brachytherapy ◽  
Radiation Induced

Radiation-induced polymerization of methyl methacrylate and alkyl acrylates at high dose rate

1988 ◽  
Vol 36 (2) ◽  
pp. 295-308 ◽  
Author(s):  
Kanae Hayashi ◽  
Jun'ichi Takezaki ◽  
Toshio Okada ◽  
Ichiro Sakurada
Keyword(s):  
Methyl Methacrylate ◽  
Dose Rate ◽  
High Dose Rate ◽  
High Dose ◽  
Alkyl Acrylates ◽  
Radiation Induced

scholarly journals The Effect of High-Dose-Rate Pulsed Radiation on the Survival of Clinically Relevant Radioresistant Cells

Life ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1295
Author(s):  
Shingo Terashima ◽  
Hironori Yoshino ◽  
Yoshikazu Kuwahara ◽  
Hiro Sakuraba ◽  
Yoichiro Hosokawa
Keyword(s):  
Cell Survival ◽  
Dose Rate ◽  
High Dose Rate ◽  
High Dose ◽  
Dna Double Strand Breaks ◽  
Single Exposure ◽  
Strand Breaks ◽  
Cell Line Cell ◽  
Radiation Induced ◽  
Induced Apoptosis

We demonstrated that low dose pulsed radiation (0.25 Gy) at a high-dose-rate, even for very short intervals (10 s), decreases cell survival to a greater extent than single exposure to a similar total dose and dose rate. The objective of this study was to clarify whether high-dose-rate pulsed radiation is effective against SAS-R, a clinically relevant radioresistant cell line. Cell survival following high-dose-rate pulsed radiation was evaluated via a colony assay. Flow cytometry was utilized to evaluate γH2AX, a molecular marker of DNA double-strand breaks and delayed reactive oxygen species (ROS) associated with radiation-induced apoptosis. Increased cytotoxicity was observed in SAS-R and parent SAS cells in response to high dose rate pulsed radiation compared to single dose, as determined by colony assays. Residual γH2AX in both cells subjected to high-dose-rate pulsed radiation showed a tendency to increase, with a significant increase observed in SAS cells at 72 h. In addition, high-dose-rate pulsed radiation increased delayed ROS more than the single exposure did. These results indicate that high-dose-rate pulsed radiation was associated with residual γH2AX and delayed ROS, and high-dose-rate pulsed radiation may be used as an effective radiotherapy procedure against radioresistant cells.

High Dose Rate Oxygen Implantation for Formation of Silicon-on-Insulator Structures

1990 ◽  
Vol 201 ◽  
Author(s):  
E. Cortesi ◽  
F. Namavar ◽  
R. F. Pinizzotto ◽  
H. Yang
Keyword(s):  
Dose Rate ◽  
Silicon Surface ◽  
High Dose Rate ◽  
Silicon On Insulator ◽  
High Dose ◽  
Surface Oxide Layer ◽  
Dose Rates ◽  
Pit Formation ◽  
Lower Dose Rate ◽  
Very High

AbstractWe have studied Separation by IMplantation of OXygen (SIMOX) processes using very high dose rates (40–60 μA/cm2). For a dose of 4 × 1017 O+/cm2 at 160 keV, the structure formed by implantation at 50 μA/cm2 is very similar to that associated with lower dose rates. The same dose implanted at a dose rate of 60 μA/cm2, however, results in the formation of pits in the silicon surface as well as a somewhat different oxide structure. Implantation through a surface oxide layer appears to result in a structure similar to that associated with lower dose rate implantation. These and higher dose samples suggest that the threshold for pit formation is related to both dose rate and dose.

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