Abstract：
:The statistical distribution of the number of ion pairs per ionizing event in a small volume simulating a tissue sphere was obtained by applying the Expectation-Maximization (EM) algorithm to experimental spectra measured by exposing a Rossi-type spherical proportional counter to gamma radiation. The normalized experimental spectrum, r(x), which is the distribution of the number of ion pairs per event from both the primary track and the subsequent electron multiplication, can be represented as Sum(n) p(n) x f(n,x), where the f(n,x)'s for n = 1, 2, 3, ..., n are the normalized spectra for exactly 1, 2, 3, ..., n primary ion pairs and are calculated by convoluting the single-electron spectrum. The coefficients pn represent the mixing proportions of the spectra corresponding to 1, 2, 3, ..., n ion pairs in forming the experimental spectrum. The single-electron spectrum used in our calculations is the distribution of the number of ion pairs due to the multiplication process, and it is represented in analytical form by the Gamma distribution f(1,x) = a x x(b) x e(-cx), where x is energy, usually in eV, and a, b and c are constants. The EM algorithm is an iterative procedure for computing the maximum likelihood or maximum a posteriori estimates of the mixing proportions p(n), which we also refer to as the primary distribution of ion pairs in a microscopic spherical tissue-equivalent volume. The experimental and primary spectra are presented for simulated tissue spheres ranging from 0.25 to 8 microm in diameter exposed to 60Co gamma radiation.
journal_name
Radiat Resjournal_title
Radiation researchauthors
Obelić B,Srdoc D,Djurić PM,Marino SAsubject
Has Abstractpub_date
1998-05-01 00:00:00pages
411-5issue
5eissn
0033-7587issn
1938-5404journal_volume
149pub_type
杂志文章abstract：:This laboratory previously demonstrated that hyperbaric oxygen and hyperbaric carbogen improved oxygenation in the R3230Ac tumor, but normobaric 100% O2 and carbogen did not. The current study assessed tumor growth after exposure to radiation plus either hyperbaric oxygen, carbogen or carbogen/nicotinamide and the rel...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1997-06-01 00:00:00
abstract：:Changes in the free-cell population of the lungs of two strains of mice (SAS/4 and CBA/H) were studied up to 4 months after inhalation exposure to a sized fraction of 239PuO2 particles (1.5 micron AMAD) to give initial alveolar depositions (IADs) ranging from 17 to 810 Bq. A sample of the free-cell population of the l...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1986-03-01 00:00:00
abstract：:The investigation of fragment length distributions of plasmid DNA gives insight into the influence of localized energy distribution on the induction of DNA damage, particularly the clustering of double-strand breaks. We present an approach that determines the fragment length distributions of plasmid DNA after heavy-io...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR1028.1
更新日期：2008-06-01 00:00:00
abstract：:Exposure of cells to heat induces thermotolerance, a transient resistance to subsequent heat challenges. It has been shown that thermotolerance is correlated in time with the enhanced synthesis of heat shock proteins. In this study, the association of induced heat shock proteins with various cellular fractions was inv...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1985-03-01 00:00:00
abstract：:We tested the possibility that hyperthermia kills HA-1 cells in a manner analogous to growth factor deprivation. HA-1 cells were inactivated by serum starvation when incubated in Eagle's MEM at a density of 40 cells/cm2 or less. Cells became resistant to the absence of serum when the cell density was greater than 400 ...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1988-03-01 00:00:00
abstract：:The relationship between apoptosis induced by gamma radiation and glutathione in cells of two human cancer cell lines, HeLa from cervix carcinoma and MCF-7 from mammary carcinoma, was examined. MCF-7 cells appeared to be more radioresistant than HeLa cells, and radiation-induced apoptosis, which was monitored by asses...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR0578.1
更新日期：2007-03-01 00:00:00
abstract：:Several studies over recent years have highlighted the possibility that radiation can induce transmissible genomic instability. Most of these involve in vitro irradiation and usually in vitro culture. Here it is reported that the short-half-life bone-seeking alpha-particle emitter (224)Ra did not induce excess transmi...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/0033-7587(2001)155[0345:lodtci]2.0.co;2
更新日期：2001-02-01 00:00:00
abstract：:Alpha-particle irradiation of cells damages not only the irradiated cells but also nontargeted bystander cells. It has been proposed that the bystander effect is caused by oxidants and free radicals generated by the radiation. Recent studies have shown that α(1)-microglobulin protects against cell damage caused by oxi...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR2213.1
更新日期：2010-11-01 00:00:00
abstract：:Cognitive impairments after brain irradiation seriously affect quality of life for patients, and there is currently no effective treatment. In this study using an irradiated rat model, the role of electroacupuncture was investigated for treatment of radiation-induced brain injury. Animals received 10 Gy exposure to th...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR14561.1
更新日期：2017-06-01 00:00:00
abstract：:The mechanisms underlying hepatocellular damage after irradiation are obscure. We identified genes induced by radiation in isolated rat hepatocytes in vitro by cDNA array gene expression analysis and then screened in vivo experiments with those same genes using real-time PCR and Western blotting. Hepatocytes were irra...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/rr3503.1
更新日期：2006-03-01 00:00:00
abstract：:The hypothesis of boron neutron capture therapy (BNCT) research has been that the short-range, high-linear energy transfer radiation produced by the capture of thermal neutrons by (10)B will potentially control tumor and spare normal tissue only if the boron compound selectively targets tumor tissue within the treatme...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR3592.1
更新日期：2006-08-01 00:00:00
abstract：:Single crystals of the co-crystalline complex of 1-methyluracil and 9-ethyladenine were X-irradiated and studied using EPR, ENDOR and FSE spectroscopic techniques at 10 K. All together seven radicals were identified, and experimental evidence for at least one more species, as well as for a very low population of radic...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1998-02-01 00:00:00
abstract：:We used Restriction Landmark Genome Scanning (RLGS) to assess, on a genome-wide basis, the mutation induction rate in mouse germ cells after radiation exposure. Analyses of 1,115 autosomal NotI DNA fragments per mouse for reduced spot intensity, indicative of loss of one copy, in 506 progeny derived from X-irradiated ...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/rr3146
更新日期：2004-04-01 00:00:00
abstract：:The effects of bromodeoxyuridine (BrdUrd) substitution for thymidine on gamma-ray-induced strand breakage were determined in single- and double-stranded oligonucleotides and double-stranded oligonucleotides containing a mismatched bubble region. BrdUrd does not sensitize complementary double-stranded DNA to gamma-ray-...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/rr3267
更新日期：2004-12-01 00:00:00
abstract：:While the risk of lung cancer associated separately with smoking and radiation exposure has been widely reported, it is not clear how smoking and radiation together contribute to the risk of specific lung cancer histological types. With individual smoking histories and radiation dose estimates, we characterized the jo...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/rr2819.1
更新日期：2012-09-01 00:00:00
abstract：:The percentage of T lymphocytes of atomic bomb survivors showed no change as a function of age or exposure dose. The percentage of T cells was slightly lower in malignant-tumor patients than in the control group, but was significantly higher in the group with chromosomal aberrations than in the control group. The perc...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1983-03-01 00:00:00
abstract：:Polonium-210 is a naturally occurring radioactive element that decays by emitting an alpha particle. It is in the air we breathe and also a component of tobacco smoke. Polonium-210 is used as an anti-static device in printing presses and gained widespread notoriety in 2006 after the poisoning and subsequent death of a...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR13395.1
更新日期：2014-02-01 00:00:00
abstract：:The mechanisms underlying the hyper-radiosensitivity of AT cells were investigated by analyzing chromosome aberrations in the G(2) and M phases of the cell cycle using a combination of chemically induced premature chromosome condensation (PCC) and fluorescence in situ hybridization (FISH) with chromosome painting prob...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/0033-7587(2003)159[0597:rcaiat]2.0.co;2
更新日期：2003-05-01 00:00:00
abstract：:The Radiological Research Accelerator Facility (RARAF) is in its 50th year of operation. It was commissioned on April 1, 1967 as a collaboration between the Radiological Research Laboratory (RRL) of Columbia University, and members of the Medical Research Center of Brookhaven National Laboratory (BNL). It was initiall...
journal_title：Radiation research
pub_type： 历史文章,杂志文章
doi：10.1667/RR002CC.1
更新日期：2017-04-01 00:00:00
abstract：:Ion microscopy was used for subcellular quantitative imaging of the isotopes 10B and 11B in the same cell to evaluate boron delivery using a mixture of two neutron capture therapy drugs, p-boronophenylalanine-fructose (BPA-F) and sodium borocaptate (BSH). The application of 10B-labeled BPA-F and 11B-labeled BSH allowe...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/0033-7587(2002)157[0700:qssims]2.0.co;2
更新日期：2002-06-01 00:00:00
abstract：:Survival of colony-forming units-spleen (CFU-S) was measured after single doses of photons or heavy charged particles from the BEVALAC. The purposes were to define the radiosensitivity to heavy ions used medically and to evaluate relationships between relative biological effectiveness (RBE) and dose-averaged linear en...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1983-10-01 00:00:00
abstract：:Incorporation of bromodeoxyuridine (BrdU) into DNA in both Chinese hamster ovary (CHO) cells and human melanoma (U1) cells reduced the rate of DNA migration in transverse alternating-field electrophoresis (TAFE) agarose gel optimized for separating molecules larger than 2 Mb. This "BrdU migration effect" was independe...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1994-04-01 00:00:00
abstract：:The effects of (56)Fe particles and (137)Cs gamma radiation were compared in TK6 and WTK1 human lymphoblasts, two related cell lines which differ in TP53 status and in the ability to rejoin DNA double-strand breaks. Both cell lines were more sensitive to the cytotoxic and clastogenic effects of (56)Fe particles than t...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/0033-7587(2001)156[0186:geohei]2.0.co;2
更新日期：2001-08-01 00:00:00
abstract：:The relationship between intracellular and extracellular pH was investigated in a murine tumor and normal tissue, prior to and following glucose injection. Isotransplants of the murine tumor FSa-II in the dorsum of the hind foot and leg muscle, were investigated in nonanesthetized mice. Extracellular pH was measured w...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1991-05-01 00:00:00
abstract：:We investigated delayed reproductive death and chromosome bridge formation in mitotic cells in colonies of normal human embryonic cells which survived exposure to 6 Gy of X rays. Eighteen primary clones each derived from control and irradiated cultures were isolated and secondary colonies were grown up. Six of the pri...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1998-10-01 00:00:00
abstract：:Relationships based on the microdosimetric-kinetic model are presented that calculate the average number of lethal lesions, and the associated cell survival, produced in mammalian cells by exposure to protracted continuous irradiation by temporary and permanent implantation of radioactive sources. The influence of cel...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR13558.1
更新日期：2014-07-01 00:00:00
abstract：:The filter elution technique using nondenaturing conditions is widely used to assay DNA double-strand break (DSB) induction and repair. It has been reported that in the measurement of strand breaks higher rates of elution and of initial rejoining are obtained at pH 9.6 compared to pH 7.2. In the present experiments ne...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1989-09-01 00:00:00
abstract：:Ionizing radiation induces chronic metabolic oxidative stress and a mutator phenotype in hamster fibroblasts that is mediated by H(2)O(2), but the intracellular source of H(2)O(2) is not well defined. To determine the role of mitochondria in the radiation-induced mutator phenotype, end points of mitochondrial function...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR1617.1
更新日期：2009-12-01 00:00:00
abstract：:In a series of Russian and Ukrainian papers published from 1974-1986, it was reported that 30-day whole-body exposures to continuous-wave (CW) radiofrequency (RF) radiation at 2375 MHz and 5 W/m(2) disrupted the antigenic structure of rat brain tissue. The authors suggested that this action caused an autoimmune respon...
journal_title：Radiation research
pub_type： 杂志文章
doi：10.1667/RR1541.1
更新日期：2009-11-01 00:00:00
abstract：:These assessment of the consequences of irradiation on chromatin is complicated by endogenous nucleases. Isolation and prolonged storage of rat liver nuclei in buffers containing divalent metal ions activates these enzymes and promotes the degradation of chromatin. Irradiation of rat liver nuclei to dose levels of 20,...
journal_title：Radiation research
pub_type： 杂志文章
doi：
更新日期：1984-08-01 00:00:00
