Radiotherapy is under investigation for its ability to enhance responses to immunotherapy. However, the mechanisms by which radiation induces anti-tumour T cells remain unclear. We show that the DNA ...exonuclease Trex1 is induced by radiation doses above 12-18 Gy in different cancer cells, and attenuates their immunogenicity by degrading DNA that accumulates in the cytosol upon radiation. Cytosolic DNA stimulates secretion of interferon-β by cancer cells following activation of the DNA sensor cGAS and its downstream effector STING. Repeated irradiation at doses that do not induce Trex1 amplifies interferon-β production, resulting in recruitment and activation of Batf3-dependent dendritic cells. This effect is essential for priming of CD8
T cells that mediate systemic tumour rejection (abscopal effect) in the context of immune checkpoint blockade. Thus, Trex1 is an upstream regulator of radiation-driven anti-tumour immunity. Trex1 induction may guide the selection of radiation dose and fractionation in patients treated with immunotherapy.
It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic ...field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Decay products of radioactive materials may attach to ambient fine particles and form radioactive aerosol. Internal ionizing radiation source from inhaled radioactive aerosol may contribute to the ...fine particulate matter (PM2.5)-inflammation pathway. However, few studies in humans have examined the associations.
To examine the associations between particle radioactivity and biomarkers of oxidative stress and inflammation among participants from the Framingham Offspring and Third Generation cohorts.
We included 3996 participants who were not current smokers and lived within 50 km from our central air pollution monitoring station. We estimated regional mean gross beta radioactivity from monitors in the northeastern U.S. as a surrogate for ambient radioactive particles, and calculated the 1- to 28-day moving averages. We used linear regression models for fibrinogen, tumor necrosis factor α, interleukin-6, and myeloperoxidase which were measured once, and linear mixed effect models for 8-epi-prostaglandin F2α, C-reactive protein, intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1), P-selectin, and tumor necrosis factor receptor-2 that were measured up to twice, adjusting for demographics, individual- and area-level socioeconomic positions, time, meteorology, and PM2.5. We also examined whether the associations differed by median age, sex, diabetes status, PM2.5 levels, and black carbon levels.
The mean age was 54 years and 54% were women. An interquartile range (3 × 10−3 pCi/m3) higher beta radioactivity level at the 7-day moving average was associated with 5.09% (95% CI: 0.92, 9.43), 2.65% (1.10, 4.22), and 4.71% (95% CI: 3.01, 6.44) higher levels of interleukin-6, MCP-1, and P-selectin, but with 7.01% (95% CI: −11.64, −2.15) and 2.70% (95% CI: −3.97, −1.42) lower levels of 8-epi-prostaglandin F2α and ICAM-1, respectively.
Regional mean particle radioactivity was positively associated with interleukin-6, MCP-1, and P-selectin, but negatively with ICAM-1 and 8-epi-prostaglandin F2α among our study participants.
Associations between the 7-day moving average of regional mean gross beta radioactivity (per 3 × 10−3 pCi/m3) and levels of oxidative stress and inflammation biomarkers among participants from the Framingham Offspring and Third Generation cohorts. Display omitted
•Decay products of ambient radioactive materials can attach to ambient particles.•Inhaled radioactive particles may form an ionizing radiation source in the lung.•Few studies studied the associations of particle radioactivity with inflammation.•Particle radioactivity was associated with inflammation adjusting for air pollution.•Associations differed by age, sex, diabetes status and ambient air pollution levels.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•LiF-B2O3-SiO2 glass is developed for alpha and beta detectors.•Glass-ceramics with LiF has better luminescence than the as-made glass.•Glass-ceramics has comparable level of TL signal to commercial ...crystalline material.
The oxyfluoride glass and glass-ceramics from the LiF-B2O3-SiO2 system are developed. The stable glass can be produced in the range of 20–40 mol% LiF. The effect of LiF admixture on the thermal stability of the glass as well as the thermoluminescence (TL) properties such as glow curves shape is studied. The results show that the increase of lithium fluoride content in the borosilicate glass causes efficiency enhancement of the thermoluminescence signal. We have clearly stated that the process of controlled crystallization of the oxyfluoride glasses can lead again to increased intensity of the TL process. The glass-ceramics with 40 mol% LiF reveals similar level of TL signal to commercially used doped LiF material and can be considered as active material for alpha and beta radiation detectors.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
One of the major constraints of measurements of atomic hydrogen densities using two-photon absorption laser induced fluorescence in most plasma and combustion environments is the ...determination of fluorescence decay times (
τ
fluo H
), especially when using nanosecond-lasers or slow acquisition systems. Therefore, it is necessary to identify the depopulation processes of the laser excited level in order to correctly estimate
τ
fluo H
. In this study, depopulation mechanisms of atomic hydrogen excited by two-photon absorption to the
n
= 3 level (H(
n
= 3)) have been investigated using a picosecond-laser excitation and acquisition of fluorescence by a streak camera, which allowed for direct measurement of
τ
fluo H
and hence, the atomic hydrogen densities, in an H
2
microwave plasma operating in the pressure range 20–300 Pa. By combining these measurements with a detailed H(
n
= 3) collisional radiative depopulation model, it was found that full mixing amongst the H(
n
= 3) sub-levels occurs in our discharge conditions, even at a pressure as low as 20 Pa. Moreover, it is also seen that the Lyman
β
line is only partially trapped, as its escape factor
Λ
31
decreases from 0.94–0.98 down to 0.58–0.86 while the measured atomic hydrogen density rises from
8
±
5
×
10
19
m
−
3
to
9
±
6
×
10
20
m
−
3
. This means that the radiative decay rate of H(
n
= 3) atoms varies with pressure and the classical Stern–Volmer method used to determine the quenching cross-section of excited H(
n
= 3) in collisions with H
2
molecules,
σ
Q
H
n
=
3
/
H
2
, is not valid for our measurements. We used two different physics-based approaches, and show that the quenching cross-section
σ
Q
H
n
=
3
/
H
2
lies in the range 90–
106
×
10
−
20
m
2
, which can be averaged as
98
±
8
×
10
−
20
m
2
. This substantially improved estimation of
σ
Q
H
n
=
3
/
H
2
obtained in this work will be useful for the accurate estimation of H(
n
= 3) fluorescence decay times and therefore the atomic hydrogen densities.
Studying CaSO4:Eu as an OSL phosphor Guckan, Veysi; Altunal, Volkan; Nur, Necmettin ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
09/2017, Volume:
407
Journal Article
Peer reviewed
•CaSO4:Eu synthesis using precipitation method and structure analysis.•Investigation of optically stimulated properties of CaSO4:Eu phosphor.•Dosimetric characteristics of CaSO4:Eu.•Thermal effects ...on OSL properties.•Calculation of kinetic parameters.
This study was carried out to investigate the properties of the OSL signal from Eu-doped calcium sulfate (CaSO4:Eu) phosphor and study on its thermal behavior as a function of temperature under a series of luminescence experiments. The suitability of its usage as an optically stimulated luminescence (OSL) dosimeter was also checked. CaSO4:Eu was synthesized using the precipitation method and prepared in pellet form. The dopant concentration value was performed as 0.1mol%. The synthesized CaSO4:Eu was analyzed by X-ray diffraction (XRD) method to confirm the product. To have an idea about the crystallography and microstructure morphology of the material, scanning electron microscope (SEM) analysis were carried out. It was found that the OSL signal is a resultant signal having three components and exhibits thermal quenching above 150°C. The excitation spectrum of CaSO4:Eu showed different peaks in the region 220–360nm with the highest one at 269nm. Thermoluminescence (TL) signals of CaSO4:Eu pellets were obtained and compared with the TL signals obtained after OSL measurements of the same pellets by blue light stimulation. The low temperature peak near 180 °C did not show any significant change in TL after OSL measurement whereas the high temperature peak at 240°C was bleached with the blue light illumination and might be responsible for the observed OSL signal.
The dosimetric properties such as dose response, minimum detectable dose, energy response, reusability, fading properties, thermal stability and effect of reading temperatures on OSL signals were examined. OSL signals of CaSO4:Eu pellets were decreased by approximately 8% at the end of the 24h and by about 7% at the end of 28days when compared with the first readout. The thermal stability of the ∼240 °C TL peak and OSL signal using isothermal decay measurements were used to determine the trap parameters. The CaSO4:Eu OSL dosimeter in accordance with the presented study allows a high-sensitivity OSL phosphor whose host material was previously known as conventional synthetic CaSO4 TLD material.
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Ionizing radiation dosimetry with thermoluminescence (TL) materials based on silicon or glass can be interesting in its potential use in radiation monitoring as the solution to the constant looking ...of development of new radiation detectors. In this work, TL characteristics of sodium silicate exposed to beta radiation effects were studied. TL response beta irradiated exhibited a glow curve with two peaks centered at 398 K and 473 K. Samples showed linearity from 0.55 to 13.2 Gy. TL readings after 10 times showed a repeatability with an error of less than 1%. Remain information showed significant losses during the first 24 h, but its information was almost constant after 72 h of storage. The Tmax-Tstop method exhibited three peaks which were mathematically analyzed with a general order deconvolution finding kinetic orders close to the second order for the first peak, meanwhile the kinetic order for the second peak and third peak are close to second order. Finally, the VHR method showed anomalous TL glow curve behavior with an increasing intensity TL as the heating rate increased.
•Sodium Silicate Glass is good candidate for beta radiation monitoring applications.•Tl glow curve has two main peaks. They are composed of shallow and deep traps.•Trivalent ions Pr3+ modified the TL intensity of Sodium Silicate Glass.•TL glow curve deconvolution shows three peaks.•TL behavior observed is anomalous when varying the heating rate VHR.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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