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Radiation physics

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https://www.readbyqxmd.com/read/29330481/fdxr-is-a-biomarker-of-radiation-exposure-in-vivo
#1
Gráinne O'Brien, Lourdes Cruz-Garcia, Matthäus Majewski, Jakub Grepl, Michael Abend, Matthias Port, Aleš Tichý, Igor Sirak, Andrea Malkova, Ellen Donovan, Lone Gothard, Sue Boyle, Navita Somaiah, Elizabeth Ainsbury, Lucyna Ponge, Krzysztof Slosarek, Leszek Miszczyk, Piotr Widlak, Edward Green, Neel Patel, Mahesh Kudari, Fergus Gleeson, Volodymyr Vinnikov, Viktor Starenkiy, Sergii Artiukh, Leonid Vasyliev, Azfar Zaman, Christophe Badie
Previous investigations in gene expression changes in blood after radiation exposure have highlighted its potential to provide biomarkers of exposure. Here, FDXR transcriptional changes in blood were investigated in humans undergoing a range of external radiation exposure procedures covering several orders of magnitude (cardiac fluoroscopy, diagnostic computed tomography (CT)) and treatments (total body and local radiotherapy). Moreover, a method was developed to assess the dose to the blood using physical exposure parameters...
January 12, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29329599/gallbladder-ascariasis-in-kosovo-focus-on-ultrasound-and-conservative-therapy-a-case-series
#2
Vlora Ismaili-Jaha, Halim Toro, Lidvana Spahiu, Mehmedali Azemi, Teuta Hoxha-Kamberi, Muharrem Avdiu, Shqipe Spahiu-Konjusha, Luan Jaha
BACKGROUND: Ascaris lumbricoides is one of the most common intestinal infections in developing countries, including Kosovo. In contrast to migration to the bile duct, migration of the worm to the gallbladder, due to the narrow and tortuous nature of the cystic duct, is rare. When it does occur, it incites acalculous cholecystitis. CASE PRESENTATIONS: This case series describes a 16-month-old Albanian girl, a 22-month-old Albanian girl, a 4-year-old Albanian girl, and a 10-year-old Albanian boy...
January 13, 2018: Journal of Medical Case Reports
https://www.readbyqxmd.com/read/29328718/charge-catastrophe-and-dielectric-breakdown-during-exposure-of-organic-thin-films-to-low-energy-electron-radiation
#3
A Thete, D Geelen, S J van der Molen, R M Tromp
The effects of exposure to ionizing radiation are central in many areas of science and technology, including medicine and biology. Absorption of UV and soft-x-ray photons releases photoelectrons, followed by a cascade of lower energy secondary electrons with energies down to 0 eV. While these low energy electrons give rise to most chemical and physical changes, their interactions with soft materials are not well studied or understood. Here, we use a low energy electron microscope to expose thin organic resist films to electrons in the range 0-50 eV, and to analyze the energy distribution of electrons returned to the vacuum...
December 29, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29327017/a-significant-role-of-non-thermal-equilibrated-electrons-in-the-formation-of-deleterious-complex-dna-damage
#4
Takeshi Kai, Akinari Yokoya, Masatoshi Ukai, Kentaro Fujii, Tomohiro Toigawa, Ritsuko Watanabe
Although most of the radiation damage to genomic DNA could be rendered harmless using repair enzymes in a living cell, a certain fraction of the damage is persistent resulting in serious genetic effects, such as mutation induction. In order to understand the mechanisms of the deleterious DNA damage formation in terms of its earliest physical stage at the radiation track end, dynamics of low energy electrons and their thermalization processes around DNA molecules were investigated using a dynamic Monte Carlo code...
January 12, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29326118/observation-of-bulk-fermi-arc-and-polarization-half-charge-from-paired-exceptional-points
#5
Hengyun Zhou, Chao Peng, Yoseob Yoon, Chia Wei Hsu, Keith A Nelson, Liang Fu, John D Joannopoulos, Marin Soljačić, Bo Zhen
The ideas of topology have found tremendous success in closed physical systems, but even richer properties exist in the more general open or dissipative framework. We theoretically propose and experimentally demonstrate a bulk Fermi arc that develops from non-Hermitian radiative losses in an open system of photonic crystal slabs. Moreover, we discover half-integer topological charges in the polarization of far-field radiation around the bulk Fermi arc. Both phenomena are shown to be direct consequences of the non-Hermitian topological properties of exceptional points, where resonances coincide in their frequencies and linewidths...
January 11, 2018: Science
https://www.readbyqxmd.com/read/29325801/editorial-the-role-of-medical-physics-in-lung-sbrt
#6
EDITORIAL
Pietro Mancosu, Andrew Nisbet, Núria Jornet
Stereotactic body radiation therapy (SBRT) has become a standard treatment for non-operable patients with early stage non-small cell lung cancer (NSCLC). In this context, medical physics community has largely helped in the starting and the growth of this technique. In fact, SBRT requires the convergence of many different features for delivering large doses in few fractions to small moving target in an heterogeneous medium. The special issue of last month, was focused on the different physics challenges in lung SBRT...
January 9, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/29321544/a-gaussian-extension-for-diffraction-enhanced-imaging
#7
Fulvia Arfelli, Alberto Astolfo, Luigi Rigon, Ralf Hendrik Menk
Unlike conventional x-ray attenuation one of the advantages of phase contrast x-ray imaging is its capability of extracting useful physical properties of the sample. In particular the possibility to obtain information from small angle scattering about unresolvable structures with sub-pixel resolution sensitivity has drawn attention for both medical and material science applications. We report on a novel algorithm for the analyzer based x-ray phase contrast imaging modality, which allows the robust separation of absorption, refraction and scattering effects from three measured x-ray images...
January 10, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29317689/high-energy-short-duration-bursts-of-coherent-terahertz-radiation-from-an-embedded-plasma-dipole
#8
Kyu Been Kwon, Teyoun Kang, Hyung Seon Song, Young-Kuk Kim, Bernhard Ersfeld, Dino A Jaroszynski, Min Sup Hur
Emission of radiation from electrons undergoing plasma oscillations (POs) at the plasma frequency has attracted interest because of the existence of intriguing and non-trivial coupling mechanism between the electrostatic PO and the emitted electromagnetic wave. While broadband emission from plasma waves in inhomogeneous plasma is well known, the underlying physics of narrowband emission at the plasma frequency observed in experiments and in solar radio-bursts is obscure. Here we show that a spatially-localized plasma dipole oscillation (PDO) can be generated when electrons are trapped in a moving train of potential wells produced by the ponderomotive force of two slightly detuned laser pulses that collide in plasma and give rise to a burst of quasi-monochromatic radiation...
January 9, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29316969/proton-and-helium-ion-radiotherapy-for-meningioma-tumors-a-monte-carlo-based-treatment-planning-comparison
#9
Thomas Tessonnier, Andrea Mairani, Wenjing Chen, Paola Sala, Francesco Cerutti, Alfredo Ferrari, Thomas Haberer, Jürgen Debus, Katia Parodi
BACKGROUND: Due to their favorable physical and biological properties, helium ion beams are increasingly considered a promising alternative to proton beams for radiation therapy. Hence, this work aims at comparing in-silico the treatment of brain and ocular meningiomas with protons and helium ions, using for the first time a dedicated Monte Carlo (MC) based treatment planning engine (MCTP) thoroughly validated both in terms of physical and biological models. METHODS: Starting from clinical treatment plans of four patients undergoing proton therapy with a fixed relative biological effectiveness (RBE) of 1...
January 9, 2018: Radiation Oncology
https://www.readbyqxmd.com/read/29315944/the-effectiveness-of-a-saline-mouth-rinse-regimen-and-education-programme-on-radiation-induced-oral-mucositis-and-quality-of-life-in-oral-cavity-cancer-patients-a-randomised-controlled-trial
#10
B-S Huang, S-C Wu, C-Y Lin, K-H Fan, J T-C Chang, S-C Chen
Radiation therapy (RT) and concurrent chemotherapy RT (CCRT) generate radiation-induced oral mucositis (OM) and lower quality of life (QOL). This study assessed the impact of a saline mouth rinse regimen and education programme on radiation-induced OM symptoms, and QOL in oral cavity cancer (OCC) patients receiving RT or CCRT. Ninety-one OCC patients were randomly divided into a group that received saline mouth rinses and an education programme and a control group that received standard care. OM symptoms and QOL were assessed with the WHO Oral Toxicity Scale, MSS-moo and UW-QOL...
January 9, 2018: European Journal of Cancer Care
https://www.readbyqxmd.com/read/29314034/effect-of-drying-methods-microwave-vacuum-freeze-hot-air-and-sun-drying-on-physical-chemical-and-nutritional-attributes-of-five-pepper-capsicum-annuum-var-annuum-cultivars
#11
Vaibhav Kumar Maurya, Kodiveri Muthukaliannan Gothandam, Vijay Ranjan, Amita Shakya, Sunil Pareek
BACKGROUND: A randomized block design experiment was performed to investigate the influence of drying on the physical, chemical and nutritional quality attributes of five prominent cultivars of India under sun drying (SD) (mean temperature 35.5 o C, average daily radiation 5.26kWh/m-2 and mean relative humidity 73.66% RH), hot air drying (HD) at 65 °C, microwave-vacuum drying (MVD) (800W- 5KPa) and freeze drying (FD) (-50 °C, 5KPa). Water activity, pH, total phenolic content (TPC), ascorbic acid (AA), capsaicin, β-carotene, color, and Scoville heat unit were studied...
January 4, 2018: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/29313300/the-effect-of-educational-intervention-based-on-health-belief-model-and-social-support-on-promoting-skin-cancer-preventive-behaviors-in-a-sample-of-iranian-farmers
#12
Ali Khani Jeihooni, Tayebeh Rakhshani
Skin cancer is one of the most common cancers in Iran. Farmers are exposed to the sun's ultraviolet radiation due to their job and are susceptible to skin cancer. The aim of this study is to survey the effect of educational intervention based on health belief model and social support on promoting skin cancer preventive behaviors in farmers of Fasa City, Fars province, Iran. In this quasi-experimental study, 200 farmers (100 in experimental group and 100 in control group) in Fasa City, Fars, Iran, were selected in 2017...
January 8, 2018: Journal of Cancer Education: the Official Journal of the American Association for Cancer Education
https://www.readbyqxmd.com/read/29312634/experimental-verification-of-a-3d-in-vivo-dose-monitoring-system-based-on-epid
#13
Xiaoyong Wang, Lixin Chen, Conghua Xie, Dajiang Wang, Gaili Chen, Zhengming Fu, Hui Liu
Purpose: To evaluate the Edose system, a novel three-dimensional (3D) in vivo dose monitoring system based on electronic portal imaging device (EPID), prior to clinical application, we analyzed the preliminary clinical data using Edose system in patients receiving intensity-modulated radiation therapy (IMRT). Materials and methods: After the physical modeling, the measured results from the Edose system were examined in homogeneous and inhomogeneous phantoms, respectively...
December 12, 2017: Oncotarget
https://www.readbyqxmd.com/read/29309701/intense-thermal-neutron-fields-from-a-medical-type-linac-the-e_libans-project
#14
M Costa, E Durisi, M Ferrero, V Monti, L Visca, S Anglesio, R Bedogni, J M Gomez-Ros, M Romano, O Sans Planell, M Treccani, D Bortot, A Pola, K Alikaniotis, G Giannini
The e_LiBANS project aims at producing intense thermal neutron fields for diverse interdisciplinary irradiation purposes. It makes use of a reconditioned medical electron LINAC, recently installed at the Physics Department and INFN in Torino, coupled to a dedicated photo-converter, developed within this collaboration, that uses (γ,n) reaction within high Z targets. Produced neutrons are then moderated to thermal energies and concentrated in an irradiation volume. To measure and to characterize in real time the intense field inside the cavity new thermal neutron detectors were designed with high radiation resistance, low noise and very high neutron-to-photon discrimination capability...
December 22, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/29301235/factors-associated-with-maintaining-the-mental-health-of-employees-after-the-fukushima-nuclear-disaster-findings-from-companies-located-in-the-evacuation-area
#15
Masatsugu Orui, Yuriko Suzuki, Aya Goto, Seiji Yasumura
After the nuclear disaster in Fukushima on 11 March 2011, some businesses were permitted to continue operating even though they were located in the evacuation area designated by the Japanese government. The aim of this study was to examine differences in the mental health status, workplace, living environment, and lifestyle of employees in the evacuation and non-evacuation areas. We also investigated factors related to their mental health status. Data for this cross-sectional study were collected from the questionnaire responses of 647 employees at three medium-sized manufacturing companies in the evacuation and non-evacuation areas...
December 31, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29298954/computed-tomography-a-technical-review
#16
Euclid Seeram
Computed tomography (CT) is a technical and complex diagnostic imaging modality. Radiologic technologists must understand the technology well enough to optimize dose and image quality and provide excellent patient care. This article reviews essential physical principles and technical aspects of CT, including physics related to radiation attenuation and CT numbers along with general technical concepts. In addition, the article reviews multislice CT technology.
January 2018: Radiologic Technology
https://www.readbyqxmd.com/read/29298916/computed-radiography-photostimulable-phosphor-plate-receptors-effect-on-grid-conversion-factors
#17
Lauren B Noble, Melissa P Culp
BACKGROUND: Grid conversion factors were established for using grids with varying ratios for film-screen systems. Evidence from the physics community suggests that the relationship between grid conversion factors and exposure to the receptor does not apply with different types of digital imaging receptors. PURPOSE: To evaluate the relationship among analog grid conversion factors when using various grid ratios with a photostimulable phosphor plate (PSP) receptor system...
November 2017: Radiologic Technology
https://www.readbyqxmd.com/read/29290830/constructing-a-chromonome-of-yellowtail-seriola-quinqueradiata-for-comparative-analysis-of-chromosomal-rearrangements
#18
Junya Kawase, Jun-Ya Aoki, Kazuo Araki
To investigate chromosome evolution in fish species, we newly mapped 181 markers that allowed us to construct a yellowtail (Seriola quinqueradiata) radiation hybrid (RH) physical map with 1,713 DNA markers, which was far denser than a previous map, and we anchored the de novo assembled sequences onto the RH physical map. Finally, we mapped a total of 13,977 expressed sequence tags (ESTs) on a genome sequence assembly aligned with the physical map. Using the high-density physical map and anchored genome sequences, we accurately compared the yellowtail genome structure with the genome structures of five model fishes to identify characteristics of the yellowtail genome...
2018: Journal of Genomics
https://www.readbyqxmd.com/read/29290376/heat-a-primer-for-public-health-researchers
#19
Glenn R McGregor, Jennifer K Vanos
OBJECTIVES: To provide a primer on the physical characteristics of heat from a biometeorological perspective for those interested in the epidemiology of extreme heat. STUDY DESIGN: A literature search design was used. METHODS: A review of the concepts of heat, heat stress and human heat balance was conducted using Web of Sciences, Scopus and PubMed. RESULTS: Heat, as recognised in the field of human biometeorology, is a complex phenomenon resulting from the synergistic effects of air temperature, humidity and ventilation levels, radiation loads and metabolic activity...
December 28, 2017: Public Health
https://www.readbyqxmd.com/read/29289203/a-compact-low-temperature-hydrogen-ion-beam-apparatus-for-in-situ-physical-property-measurements
#20
R Nakayama, N Suzuki, M Maesato, T Nagaoka, M Arita, H Kitagawa
A new compact low-temperature hydrogen ion beam apparatus has been developed for in situ physical property measurements. Introduction of hydrogen can significantly alter the physical properties of materials. Conventional methods such as exposure to H2 gas are limited to materials having hydrogen sorption. The present method is, in principle, applicable to any material of interest. Our setup provides a facile way to conduct both low-temperature hydrogen ion beam irradiation and in situ electrical resistivity measurements, which enables observation of novel physical properties induced by the low-temperature irradiation...
December 2017: Review of Scientific Instruments
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