SEMICONDUCTOR PHYSICS Dose-rate dependence of optically stimulated luminescence signal

NASA Astrophysics Data System (ADS)

Pingqiang, Wei; Zhaoyang, Chen; Yanwei, Fan; Yurun, Sun; Yun, Zhao

2010-10-01

Optically stimulated luminescence (OSL) is the luminescence emitted from a semiconductor during its exposure to light. The OSL intensity is a function of the total dose absorbed by the sample. The dose-rate dependence of the OSL signal of the semiconductor CaS doped Ce and Sm was studied by numerical simulation and experiments. Based on a one-trap/one-center model, the whole OSL process was represented by a series of differential equations. The dose-rate properties of the materials were acquired theoretically by solving the equations. Good coherence was achieved between numerical simulation and experiments, both of which showed that the OSL signal was independent of dose rate. This result validates that when using OSL as a dosimetry technique, the dose-rate effect can be neglected.

Experimental photodynamic laser therapy for rheumatoid arthritis with a second generation photosensitizer.

PubMed

Hendrich, C; Hüttmann, G; Vispo-Seara, J L; Houserek, S; Siebert, W E

2000-01-01

Photodynamic laser therapy has been shown to be a new method for the treatment of synovitis in various animal models. Its principle is the accumulation of a photosensitizing drug in the inflamed synovium which is destroyed by photoactivation of the drug. In the present animal study we demonstrate the effect of a second-generation photosensitizer and suggest a concept for light dosimetry within the joint. We used 38 inbred rabbits for the IgG-induced arthritis model; 2 mg/kg of the benzoporphyrin derivative monoacid ring-A (BPD-MA) Verteporfin were administered 3 h before irradiation, which was performed using a 690-nm diode laser coupled to quartz glass fiber with a cylinder diffusor tip at a total light energy of either 180 or 470 J. During irradiation specific fluorescence of BPD-MA was monitored using a spectroscopy unit. The effect of the photodynamic laser therapy was documented grossly and histologically after 1 week. Within the 470 J-group a complete necrosis of the inflamed synovium was observed. The bradytrophic structures of the joint, however, remained unchanged. Throughout the 180 J-group the extent of necrosis was minor. During irradiation the tissue fluorescence of BPD-MA showed a dose-dependent decrease. Using BPD-MA as a photosensitizer a highly selective and minimal invasive synoviorthesis can be performed. At a dose of 2 mg/kg the histological effect depends on the light dose. For optimum efficacy a total energy of 470 J seems favorable. Online fluorescence detection can be used to monitor the effect of light administration. For dosimetry therefore an online tissue fluorescence detection may represent a technical solution.

Assessment of the actual light dose in photodynamic therapy.

PubMed

Schaberle, Fabio A

2018-06-09

Photodynamic therapy (PDT) initiates with the absorption of light, which depends on the spectral overlap between the light source emission and the photosensitizer absorption, resulting in the number of photons absorbed, the key parameter starting PDT processes. Most papers report light doses regardless if the light is only partially absorbed or shifted relatively to the absorption peak, misleading the actual light dose value and not allowing quantitative comparisons between photosensitizers and light sources. In this manuscript a method is presented to calculate the actual light dose delivered by any light source for a given photosensitizer. This method allows comparing light doses delivered for any combination of light source (broad or narrow band or daylight) and photosensitizer. Copyright © 2018. Published by Elsevier B.V.

An algorithm for intelligent sorting of CT-related dose parameters.

PubMed

Cook, Tessa S; Zimmerman, Stefan L; Steingall, Scott R; Boonn, William W; Kim, Woojin

2012-02-01

Imaging centers nationwide are seeking innovative means to record and monitor computed tomography (CT)-related radiation dose in light of multiple instances of patient overexposure to medical radiation. As a solution, we have developed RADIANCE, an automated pipeline for extraction, archival, and reporting of CT-related dose parameters. Estimation of whole-body effective dose from CT dose length product (DLP)--an indirect estimate of radiation dose--requires anatomy-specific conversion factors that cannot be applied to total DLP, but instead necessitate individual anatomy-based DLPs. A challenge exists because the total DLP reported on a dose sheet often includes multiple separate examinations (e.g., chest CT followed by abdominopelvic CT). Furthermore, the individual reported series DLPs may not be clearly or consistently labeled. For example, "arterial" could refer to the arterial phase of the triple liver CT or the arterial phase of a CT angiogram. To address this problem, we have designed an intelligent algorithm to parse dose sheets for multi-series CT examinations and correctly separate the total DLP into its anatomic components. The algorithm uses information from the departmental PACS to determine how many distinct CT examinations were concurrently performed. Then, it matches the number of distinct accession numbers to the series that were acquired and anatomically matches individual series DLPs to their appropriate CT examinations. This algorithm allows for more accurate dose analytics, but there remain instances where automatic sorting is not feasible. To ultimately improve radiology patient care, we must standardize series names and exam names to unequivocally sort exams by anatomy and correctly estimate whole-body effective dose.

An algorithm for intelligent sorting of CT-related dose parameters

NASA Astrophysics Data System (ADS)

Cook, Tessa S.; Zimmerman, Stefan L.; Steingal, Scott; Boonn, William W.; Kim, Woojin

2011-03-01

Imaging centers nationwide are seeking innovative means to record and monitor CT-related radiation dose in light of multiple instances of patient over-exposure to medical radiation. As a solution, we have developed RADIANCE, an automated pipeline for extraction, archival and reporting of CT-related dose parameters. Estimation of whole-body effective dose from CT dose-length product (DLP)-an indirect estimate of radiation dose-requires anatomy-specific conversion factors that cannot be applied to total DLP, but instead necessitate individual anatomy-based DLPs. A challenge exists because the total DLP reported on a dose sheet often includes multiple separate examinations (e.g., chest CT followed by abdominopelvic CT). Furthermore, the individual reported series DLPs may not be clearly or consistently labeled. For example, Arterial could refer to the arterial phase of the triple liver CT or the arterial phase of a CT angiogram. To address this problem, we have designed an intelligent algorithm to parse dose sheets for multi-series CT examinations and correctly separate the total DLP into its anatomic components. The algorithm uses information from the departmental PACS to determine how many distinct CT examinations were concurrently performed. Then, it matches the number of distinct accession numbers to the series that were acquired, and anatomically matches individual series DLPs to their appropriate CT examinations. This algorithm allows for more accurate dose analytics, but there remain instances where automatic sorting is not feasible. To ultimately improve radiology patient care, we must standardize series names and exam names to unequivocally sort exams by anatomy and correctly estimate whole-body effective dose.

ASSESSMENT OF VISUAL FUNCTION AND RETINAL STRUCTURE FOLLOWING ACUTE LIGHT EXPOSURE IN THE LIGHT SENSITIVE T4R RHODOPSIN MUTANT DOG

PubMed Central

Iwabe, Simone; Ying, Gui-Shuang; Aguirre, Gustavo D.; Beltran, William A.

2016-01-01

The effect of acute exposure to various intensities of white light on visual behavior and retinal structure was evaluated in the T4R RHO dog, a naturally-occurring model of autosomal dominant retinitis pigmentosa due to a mutation in the Rhodopsin gene. A total of 14 dogs (ages: 4–5.5 months) were used in this study: 3 homozygous mutant RHOT4R/T4R, 8 heterozygous mutant RHOT4R/+, and 3 normal wild-type (WT) dogs. Following overnight dark adaptation, the left eyes were acutely exposed to bright white light with a monocular Ganzfeld dome, while the contralateral right eye was shielded. Each of the 3 homozygous (RHOT4R/T4R) mutant dogs had a single unilateral light exposure (LE) to a different (low, moderate, and high) dose of white light (corneal irradiance/illuminance: 0.1 mW/cm2, 170 lux; 0.5 mW/cm2, 820 lux; or 1 mW/cm2, 1590 lux) for 1min. All 8 heterozygous (RHOT4R/+) mutant dogs were exposed once to the same moderate dose of light. The 3 WT dogs had their left eyes exposed 1, 2, or 3 times to the same highest dose of light. Visual function prior to LE and at 2 weeks and 33 weeks after exposure was objectively assessed in the RHOT4R/T4R and WT dogs by using an obstacle-avoidance course. Transit time through the obstacle course was measured under different scotopic to photopic ambient illuminations. Morphological retinal changes were evaluated by non-invasive in vivo cSLO/sdOCT imaging and histology before and at several time-points (2–36 weeks) after light exposure. The analysis of the transit time through the obstacle course showed that no differences were observed in any of mutant or WT dogs at 2 weeks and 33 weeks post LE. The RHOT4R/T4R retina exposed to the lowest dose of white light showed no obvious changes in ONL thickness at 2 weeks, but mild decrease was noted 36 weeks after LE. The RHOT4R/T4R retina that received a moderate dose (showed an obvious decrease in ONL thickness along the superior and temporal meridians at 2 weeks post LE with more severe damage at 36 weeks post LE in all four meridians. The RHOT4R/T4R retina exposed to the high dose showed at 2 weeks after LE extensive ONL damage in all four meridians. This light intensity did not cause any retinal damage in WT dogs even after repeated (up to 3) LE. Analysis of ONL thickness in heterozygous mutant dogs exposed to the moderate dose of light confirmed the increased sensitivity to light damage of the superior/tapetal retina, and the occurrence of an ongoing cell death process several weeks after the acute LE. In conclusion, a short single exposure to a dose of white light that is not retinotoxic in WT dogs causes in the T4R RHO retina an acute loss of ONL in the central to mid peripheral region that keeps progressing over the course of several weeks. However, this severe retinal damage does not affect visual behavior presumably because of islands of surviving photoreceptors found in the area centralis including the newly discovered canine fovea-like area, and the lack of damage to peripheral photoreceptors. PMID:27085210

Effect of irradiated pork on physicochemical properties of meat emulsions

NASA Astrophysics Data System (ADS)

Choi, Yun-Sang; Sung, Jung-Min; Jeong, Tae-Jun; Hwang, Ko-Eun; Song, Dong-Heon; Ham, Youn-Kyung; Kim, Hyun-Wook; Kim, Young-Boong; Kim, Cheon-Jei

2016-02-01

The effect of pork irradiated with doses up to 10 kGy on meat emulsions formulated with carboxy methyl cellulose (CMC) was investigated. Raw pork was vacuums packaged at a thickness of 2.0 cm and irradiated by X-ray linear accelerator (15 kW, 5 MeV). The emulsion had higher lightness, myofibrillar protein solubility, total protein solubility, and apparent viscosity with increasing doses, whereas cooking loss, total expressible fluid separation, and hardness decreased. There were no significant differences in fat separation, sarcoplasmic protein solubility, springiness, and cohesiveness. Our results indicated that it is treatment by ionizing radiation which causes the effects the physicochemical properties of the final raw meat product.

SU-F-BRE-07: Experimental Validation of a Lung SBRT Technique Using a Novel, True Volumetric Plenoptic-Plastic-Scintillator Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goulet, M; Rilling, M; Gingras, L

2014-06-15

Purpose: Lung SBRT is being used by an increasing number of clinics, including our center which recently treated its first patient. In order to validate this technique, the 3D dose distribution of the SBRT plan was measured using a previously developed 3D detector based on plenoptic camera and plastic scintillator technology. The excellent agreement between the detector measurement and the expected dose from the treatment planning system Pinnacle{sup 3} shows great promise and amply justify the development of the technique. Methods: The SBRT treatment comprised 8 non-coplanar 6MV photon fields with a mean field size of 12 cm{sup 2} atmore » isocentre and a total prescription dose of 12Gy per fraction for a total of 48Gy. The 3D detector was composed of a 10×10×10 cm{sup 2} EJ-260 water-equivalent plastic scintillator embedded inside a truncated cylindrical acrylic phantom of 10cm radius. The scintillation light was recorded using a static R5 light-field camera and the 3D dose was reconstructed at a 2mm resolution in all 3 dimensions using an iterative backprojection algorithm. Results: The whole 3D dose distribution was recorded at a rate of one acquisition per second. The mean absolute dose difference between the detector and Pinnacle{sup 3} was 1.3% over the region with more than 10% of the maximum dose. 3D gamma tests performed over the same region yield passing rates of 98.8% and 96.6% with criteria of 3%/1mm and 2%/1mm, respectively. Conclusion: Experimental results showed that our beam modeling and treatment planning system calculation was adequate for the safe administration of small field/high dose techniques such as SBRT. Moreover, because of the real-time capability of the detector, further validation of small field rotational, dynamic or gated technique can be monitored or verified by this system.« less

Interstitial photodynamic therapy for the prostate: a canine feasibility study

NASA Astrophysics Data System (ADS)

Shetty, Sugandh D.; Sirls, Larry T.; Chen, Qun; Hetzel, Fred W.; Cerny, Joseph C.

1996-05-01

Prior to a possible clinical application of photodynamic therapy (PDT) for prostatic diseases such as benign prostatic hyperplasia and prostate cancer, optical properties of the prostate gland need to be studied. The specific objectives of this study were (1) to determine the light penetration depth, (2) to document the photosensitizer levels in the prostate, and (3) to document the lesion size after PDT. Sixteen dogs were injected with Photofrin II (1, 3 and 5 mg/kg) 24 hrs prior to laser application. After laparotomy and exposure of prostate, monochromatic light (630 nm, via an argon pumped dye laser) was applied through an isotropic fiber at 100 mw for a total dose of 400 joules. Continuous light fluence and temperature were documented. Prostates were harvested at 1 week and examined histologically for the lesion size. Four sham dogs were treated without Photofrin II. At Photofrin doses of 1, 3 and 5 mg/kg the mean prostatic Photofrin levels were 1.78 plus or minus 0.33, 1.47 plus or minus 0.08 and 1.95 plus or minus 0.44 (mu) gm/ml. The mean light penetration depths were 2.08, 1.37 and 1.64 mm respectively. Photofrin dose escalation (1, 3 and 5 mg/kg) increased the lesion size to radius of 4.1 plus or minus 0.9 mm, 4.4 plus or minus 0.8 mm and 6.3 plus or minus 0.9 mm. There were no lesions seen in sham dogs. These results demonstrate that light penetration in prostate is consistent and therapeutic levels of photosensitizer are achieved in prostatic tissue. Moreover, increasing size of the lesions were documented with dose escalation.

Online dosimetry for temoporfin-mediated interstitial photodynamic therapy using the canine prostate as model

NASA Astrophysics Data System (ADS)

Swartling, Johannes; Höglund, Odd V.; Hansson, Kerstin; Södersten, Fredrik; Axelsson, Johan; Lagerstedt, Anne-Sofie

2016-02-01

Online light dosimetry with real-time feedback was applied for temoporfin-mediated interstitial photodynamic therapy (PDT) of dog prostate. The aim was to investigate the performance of online dosimetry by studying the correlation between light dose plans and the tissue response, i.e., extent of induced tissue necrosis and damage to surrounding organs at risk. Light-dose planning software provided dose plans, including light source positions and light doses, based on ultrasound images. A laser instrument provided therapeutic light and dosimetric measurements. The procedure was designed to closely emulate the procedure for whole-prostate PDT in humans with prostate cancer. Nine healthy dogs were subjected to the procedure according to a light-dose escalation plan. About 0.15 mg/kg temoporfin was administered 72 h before the procedure. The results of the procedure were assessed by magnetic resonance imaging, and gross pathology and histopathology of excised tissue. Light dose planning and online dosimetry clearly resulted in more focused effect and less damage to surrounding tissue than interstitial PDT without dosimetry. A light energy dose-response relationship was established where the threshold dose to induce prostate gland necrosis was estimated from 20 to 30 J/cm2.

Dose-response association of physical activity with acute myocardial infarction: do amount and intensity matter?

PubMed

Elosua, Roberto; Redondo, Ana; Segura, Antonio; Fiol, Miquel; Aldasoro, Elena; Vega, Gema; Forteza, Jordi; Martí, Helena; Arteagoitia, José María; Marrugat, Jaume

2013-11-01

The aims of this study were to analyze the dose-response association between leisure time physical activity (PA) practice and myocardial infarction (MI), considering not only the total amount but also the amount of PA at different levels of intensity, and to determine whether these associations were modified by age. In a population-based age- and sex-matched case-control study, all first acute MI patients aged 25 to 74 years were prospectively registered in four Spanish hospitals between 2002 and 2004. Controls were randomly selected from population-based samples recruited during the same period of time. The Minnesota PA questionnaire was administered to assess total energy expenditure in PA and in light-, moderate-, and high-intensity PA. Finally, 1339 cases and 1339 controls were included. The association between PA and MI likelihood was non-linear, with significantly lower MI odds at low practice levels (≥ 500 MET·min/week), lowest odds around 1500 MET·min/week, and a plateau thereafter. Light- (in subjects older than 64 years), moderate-, and high-intensity PA produced similar benefits. Most of the population could reduce their likelihood of MI by engaging in PA at a moderate level of intensity or, in individuals older than 64 years, at a light level of intensity. © 2013.

Radiation damage of all-silica fibers in the UV region

NASA Astrophysics Data System (ADS)

Gombert, Joerg; Ziegler, M.; Assmus, J.; Klein, Karl-Friedrich; Nelson, Gary W.; Clarkin, James P.; Pross, H.; Kiefer, J.

1999-04-01

Since several years, UVI-fibers having higher solarization- resistance are well known stimulating new fiber-optic applications in the UV-region below 250 nm. Besides the description of the improved transmission properties of UV- light from different UV-sources, the mechanisms of improvement have been discussed in detail. The UV-defects, mainly the E'- center with the UV-absorption band around 215 nm, were passivated by using hydrogen-doping. Besides DUV-light, ionizing radiation like Gamma-radiation or X-rays can create similar defects in the UV-region. In the past, the radiation- damage in the UV-region was studied on silica bulk samples: again, E'-centers were generated. Up to now, no UV- transmission through a 1 m long fiber during or after Gamma- radiation had been observed. However, the hydrogen in the UVI- fibers behaves the same for Gamma-irradiation, leading to a passivation of the radiation-induced defects and an improved transmission in the UV-C region below 250 nm. On this report, the influence of total dose and fiber diameter on the UV- damage after irradiation will be described and discussed. In addition, we will include annealing studies, with and without UV-light. Based on our results, the standard process of Gamma- sterilization with a total dose of approx. 2 Mrad can be used for UVI-fibers resulting in a good UV-transmission below 320 nm. Excimer-laser light at 308 nm (XeCl) and 248 nm (KrF) and deuterium-lamp light with the full spectrum starting at 200 nm can also be transmitted.

Accelerometer-measured dose-response for physical activity, sedentary time, and mortality in US adults.

PubMed

Matthews, Charles E; Keadle, Sarah Kozey; Troiano, Richard P; Kahle, Lisa; Koster, Annemarie; Brychta, Robert; Van Domelen, Dane; Caserotti, Paolo; Chen, Kong Y; Harris, Tamara B; Berrigan, David

2016-11-01

Moderate-to-vigorous-intensity physical activity is recommended to maintain and improve health, but the mortality benefits of light activity and risk for sedentary time remain uncertain. Using accelerometer-based measures, we 1) described the mortality dose-response for sedentary time and light- and moderate-to-vigorous-intensity activity using restricted cubic splines, and 2) estimated the mortality benefits associated with replacing sedentary time with physical activity, accounting for total activity. US adults (n = 4840) from NHANES (2003-2006) wore an accelerometer for ≤7 d and were followed prospectively for mortality. Proportional hazards models were used to estimate adjusted HRs and 95% CIs for mortality associations with time spent sedentary and in light- and moderate-to-vigorous-intensity physical activity. Splines were used to graphically present behavior-mortality relation. Isotemporal models estimated replacement associations for sedentary time, and separate models were fit for low- (<5.8 h total activity/d) and high-active participants to account for nonlinear associations. Over a mean of 6.6 y, 700 deaths occurred. Compared with less-sedentary adults (6 sedentary h/d), those who spent 10 sedentary h/d had 29% greater risk (HR: 1.29; 95% CI: 1.1, 1.5). Compared with those who did less light activity (3 h/d), those who did 5 h of light activity/d had 23% lower risk (HR: 0.77; 95% CI: 0.6, 1.0). There was no association with mortality for sedentary time or light or moderate-to-vigorous activity in highly active adults. In less-active adults, replacing 1 h of sedentary time with either light- or moderate-to-vigorous-intensity activity was associated with 18% and 42% lower mortality, respectively. Health promotion efforts for physical activity have mostly focused on moderate-to-vigorous activity. However, our findings derived from accelerometer-based measurements suggest that increasing light-intensity activity and reducing sedentary time are also important, particularly for inactive adults. © 2016 American Society for Nutrition.

SU-E-CAMPUS-T-03: Four-Dimensional Dose Distribution Measurement Using Plastic Scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hashimoto, M; Kozuka, T; Oguchi, M

2014-06-15

Purpose: To develop the detector for the four-dimensional dose distribution measurement. Methods: We made the prototype detector for four-dimensional dose distribution measurement using a cylindrical plastic scintillator (5 cm diameter) and a conical reflection grass. The plastic scintillator is used as a phantom. When the plastic scintillator is irradiated, the scintillation light was emitted according to absorbed dose distribution. The conical reflection grass was arranged to surround the plastic scintillator, which project to downstream the projection images of the scintillation light. Then, the projection image was reflected to 45 degree direction by flat reflection grass, and was recorded by camcorder.more » By reconstructing the three-dimensional dose distribution from the projection image recorded in each frame, we could obtain the four-dimensional dose distribution. First, we tested the characteristic according to the amount of emitted light. Then we compared of the light profile and the dose profile calculated with the radiotherapy treatment planning system. Results: The dose dependency of the amount of light showed linearity. The pixel detecting smaller amount of light had high sensitivity than the pixel detecting larger amount of light. However the difference of the sensitivity could be corrected from the amount of light detected in each pixel. Both of the depth light profile through the conical reflection grass and the depth dose profile showed the same attenuation in the region deeper than peak depth. In lateral direction, the difference of the both profiles was shown at outside field and penumbra region. We consider that the difference is occurred due to the scatter of the scintillation light in the plastic scintillator block. Conclusion: It was possible to obtain the amount of light corresponding to the absorbed dose distribution from the prototype detector. Four-dimensional dose distributions can be reconstructed with high accuracy by the correction of the scattered light.« less

Comparison of three light doses in the photodynamic treatment of actinic keratosis using mathematical modeling

NASA Astrophysics Data System (ADS)

Vignion-Dewalle, Anne-Sophie; Betrouni, Nacim; Tylcz, Jean-Baptiste; Vermandel, Maximilien; Mortier, Laurent; Mordon, Serge

2015-05-01

Photodynamic therapy (PDT) is an emerging treatment modality for various diseases, especially for cancer therapy. Although high efficacy is demonstrated for PDT using standardized protocols in nonhyperkeratotic actinic keratoses, alternative light doses expected to increase efficiency, to reduce adverse effects or to expand the use of PDT, are still being evaluated and refined. We propose a comparison of the three most common light doses in the treatment of actinic keratosis with 5-aminolevulinic acid PDT through mathematical modeling. The proposed model is based on an iterative procedure that involves determination of the local fluence rate, updating of the local optical properties, and estimation of the local damage induced by the therapy. This model was applied on a simplified skin sample model including an actinic keratosis lesion, with three different light doses (red light dose, 37 J/cm2, 75 mW/cm2, 500 s blue light dose, 10 J/cm2, 10 mW/cm2, 1000 s and daylight dose, 9000 s). Results analysis shows that the three studied light doses, although all efficient, lead to variable local damage. Defining reference damage enables the nonoptimal parameters for the current light doses to be refined and the treatment to be more suitable.

Emission of polycyclic aromatic hydrocarbons and lead during Chinese mid-autumn festival.

PubMed

Kuo, Chung-Yih; Lee, Hong-Shen; Lai, Jeang-Hung

2006-07-31

The emission factors of total particulate polycyclic aromatic hydrocarbons (PAHs), Benzo(a)pyrene (BaP), BaP-equivalent doses (BaP(eq)) and Pb for burning three kinds of charcoal were investigated in this study: fast-lighting charcoal, Taiwanese, and Indonesian charcoal (the latter two of which are not fast-lighting). Compared to the burning of Taiwanese and Indonesian charcoal, the burning of fast-lighting charcoal can emit much larger amounts of total PAHs, BaP(eq) and Pb into the atmosphere. The emission factors of total PAHs, BaP and BaP(eq) for broiling meat were noticeably higher than those for broiling vegetables and non-fish seafood. When using Indonesian charcoal to broil meat, the total emission factors of particulate PAHs and BaP were about 15.7 and 0.39 mg/kg, respectively. The total amounts of particulate PAHs and Pb emitted from cookouts during Mid-Autumn Festival were 2881 and 120 g, respectively. Total PAHs and BaP(eq) in PM(10) aerosols on Mid-Autumn Festival nights increased about 1.6 and 1.5 times, respectively, higher than those on non-festival nights. The mean concentration of Pb on the nights of Mid-Autumn Festival increases to about 2.8 times that of non-festival nights.

HepG2 human hepatocarcinomas cells sensitization by endogenous porphyrins

NASA Astrophysics Data System (ADS)

Vonarx-Coinsmann, Veronique; Foultier, Marie-Therese; de Brito, Leonor X.; Morlet, Laurent; Patrice, Thierry

1995-03-01

We assessed the ability of the human hepatocarcinoma cell line HepG2 to synthesize PpIX in vitro from exogenous ALA and analyzed ALA-induced toxicity and phototoxicity on this cell line. ALA induced a slight dose-dependent dark toxicity, with 79 and 66% cell survival respectively for ALA 50 and 100 mg/ml after 3-h incubation. Whereas the same treatment followed by laser irradiation (l equals 632 nm, 25 J/sq cm) induced dose-dependent phototoxicity, with 54 and 19% cell survival 24 h after PDT. Whatever the incubation time with ALA, a 3-h delay before light exposure was found optimal to reach a maximal phototoxicity. Photoproducts induced by porphyrin light irradiation absorbed light in the red spectral region at longer wavelengths than did the original porphyrins. The possible enhancement of PDT effects after ALA HepG2 cell incubation was investigated by irradiating cells successively with red light (l equals 632 nm) and light (l equals 650 nm). Total fluence was kept constant at 25 J/sq cm. Phototoxicity was lower when cells were irradiated for increased periods of l equals 650 nm light than with l equals 632 nm light alone. Any photoproducts involved had either a short life or were poorly photoreactive. HepG2 cells, synthesizing enzymes and precursors of endogenous porphyrin synthesis, represent a good in vitro model for experiments using ALA-PpIX-PDT.

γ irradiation with different dose rates induces different DNA damage responses in Petunia x hybrida cells.

PubMed

Donà, Mattia; Ventura, Lorenzo; Macovei, Anca; Confalonieri, Massimo; Savio, Monica; Giovannini, Annalisa; Carbonera, Daniela; Balestrazzi, Alma

2013-05-15

In plants, there is evidence that different dose rate exposures to gamma (γ) rays can cause different biological effects. The dynamics of DNA damage accumulation and molecular mechanisms that regulate recovery from radiation injury as a function of dose rate are poorly explored. To highlight dose-rate dependent differences in DNA damage, single cell gel electrophoresis was carried out on regenerating Petunia x hybrida leaf discs exposed to LDR (total dose 50 Gy, delivered at 0.33 Gy min(-1)) and HDR (total doses 50 and 100 Gy, delivered at 5.15 Gy min(-1)) γ-ray in the 0-24h time period after treatments. Significant fluctuations of double strand breaks and different repair capacities were observed between treatments in the 0-4h time period following irradiation. Dose-rate-dependent changes in the expression of the PhMT2 and PhAPX genes encoding a type 2 metallothionein and the cytosolic isoform of ascorbate peroxidase, respectively, were detected by Quantitative RealTime-Polymerase Chain Reaction. The PhMT2 and PhAPX genes were significantly up-regulated (3.0- and 0.7-fold) in response to HDR. The results are discussed in light of the potential practical applications of LDR-based treatments in mutation breeding. Copyright © 2013 Elsevier GmbH. All rights reserved.

Optimization of light dosimetry for photodynamic therapy of Barrett's esophagus

NASA Astrophysics Data System (ADS)

Panjehpour, Masoud; Phan, Mary N.; Overholt, Bergein F.; Haydek, John M.

2004-06-01

Background and Objective: Photodynamic therapy (PDT) may be used for ablation of high grade dysplasia and/or early cancer (HGD/T1) in Barrett's esophagus. A complication of PDT is esophageal stricture. The objective of this study was to find the lowest light dose to potentially reduce the incidence of strictures while effectively ablating HGD/T1. Materials and Methods: Patients (n=113) with HGD/T1 received an intravenous injection of porfimer sodium (2 mg/kg). Three days later, laser light (630 nm) was delivered using a cylindrical diffuser inserted in a 20 mm.diameter PDT balloon. Patients were treated at light doses of 115 J/cm, 105 J/cm, 95 J/cm and 85 J/cm. The efficacy was determined by four quadrant biopsies of the treated area three months after PDT. The formation of stricture was determined by the incidence of dysphagia and the need for esophageal dilation. Strictures were considered mild if they required less than 6 dilations, and severe if 6 or more dilations were required. Efficacy and incidence of strictures were tabulated as a function of light dose. Results: Using 115 J/cm, there were 17% of patients with residual HGD/T1 after one treatment. However, when the light doses of 105 J/cm, 95 J/cm and 85 J/cm were used, the residual HGD/T1 after one PDT session was increased to 33%, 30%, and 32% respectively. The overall incidence of strictures (mild and severe) was not correlated to the light dose. However, the incidence of severe strictures was directly proportional to the light dose. Using the light dose of 115 J/cm, 15.3% of patients developed severe strictures compared to about 5% in the groups of patients who received the lower light doses. Conclusions: Decreasing the light dose below 115 J/cm doubled the rate of residual HGD/T1 after one treatment while reducing the incidence of severe strictures to one-third of cases from 115 J/cm. The results may be used to evaluate the risks and benefits of different light doses.

Evaluating analytical ionization quenching correction models for 3D liquid organic scintillator detector

NASA Astrophysics Data System (ADS)

Alsanea, F.; Beddar, S.

2017-05-01

Proton therapy offers dosimetric advantage over conventional photon therapy due to the finite range of the proton beam, which improves dose conformity. However, one of the main challenges of proton beam therapy is verification of the complex treatment plans delivered to a patient. Thus, 3D measurements are needed to verify the complex dose distribution. A 3D organic scintillator detector is capable of such measurements. However, organic scintillators exhibit a non-linear relation to the ionization density called ionization quenching. The ionization quenching phenomenon in organic scintillators must be accounted for to obtain accurate dose measurements. We investigated the energy deposition by secondary electrons (EDSE) model to explain ionization quenching in 3D liquid organic scintillator when exposed to proton beams. The EDSE model was applied to volumetric scintillation measurement of proton pencil beam with energies of 85.6, 100.9, 144.9 and 161.9 MeV. The quenching parameter in EDSE model ρq was determined by plotting the total light output vs the initial energy of the ion. The results were compared to the Birks semi-empirical formula of scintillation light emission.

Drink and Think: Impact of Alcohol on Cognitive Functions and Dementia - Evidence of Dose-Related Effects.

PubMed

Gutwinski, Stefan; Schreiter, Stefanie; Priller, Josef; Henssler, Jonathan; Wiers, Corinde E; Heinz, Andreas

2017-09-26

Regular alcohol consumption affects cognitive performance and the development of dementia. So far, findings are contradicting, which might be explained in part by dose-related effects. For this narrative review, we undertook a literature search for surveys investigating the impact of alcohol consumption on cognitive performance and the development of dementia. The majority of studies observed a U-shaped relationship between regular alcohol consumption and cognitive function: frequent heavy consumption of alcohol alters brain functions and decreases cognitive performance; regular light and moderate consumption may have protective impact. In many studies, total abstainers show an inferior cognitive performance than people with moderate or light consumption. Nevertheless, policy implications are difficult to draw for at least 2 reasons: (1) the possible risks associated with alcohol consumption and (2) the potential confounders in the group of non-consumers and heavy consumers. © Georg Thieme Verlag KG Stuttgart · New York.

Reactive oxygen species explicit dosimetry (ROSED) of a type 1 photosensitizer

NASA Astrophysics Data System (ADS)

Ong, Yi Hong; Kim, Michele M.; Huang, Zheng; Zhu, Timothy C.

2018-02-01

Type I photodynamic therapy (PDT) is based on the use of photochemical reactions mediated through an interaction between a tumor-selective photosensitizer, photoexcitation with a specific wavelength of light, and production of reactive oxygen species (ROS). The goal of this study is to develop a model to calculate reactive oxygen species concentration ([ROS]rx) after Tookad®-mediated vascular PDT. Mice with radiation-induced fibrosarcoma (RIF) tumors were treated with different light fluence and fluence rate conditions. Explicit measurements of photosensitizer drug concentration were made via diffuse reflective absorption spectrum using a contact probe before and after PDT. Blood flow and tissue oxygen concentration over time were measured during PDT as a mean to validate the photochemical parameters for the ROSED calculation. Cure index was computed from the rate of tumor regrowth after treatment and was compared against three calculated dose metrics: total light fluence, PDT dose, reacted [ROS]rx. The tumor growth study demonstrates that [ROS]rx serves as a better dosimetric quantity for predicting treatment outcome, as a clinically relevant tumor growth endpoint.

Dosing-time-dependent variation in biliary excretion of flomoxef in rats.

PubMed

Hishikawa, Shuji; Sugimoto, Koh-ichi; Kobayashi, Eiji; Kumagai, Yuji; Fujimura, Akio

2003-05-01

We previously reported that the biliary excretion of flomoxef, an oxacephem antibiotic, was greater after dosing at 21:00 than at 09:00 h in diurnally active human subjects. The present study was undertaken to examine whether the biliary excretion of flomoxef is also dependent on its dosing time in rats. Adult male Wistar rats were housed under light on at 07:00 h and off at 19:00 h. Bile fluid was completely drained through a polyethylene catheter from conscious animals. Flomoxef (20 mg/kg) was injected into the tail vein at 09:00 or 21:00 h by a cross-over design, and drained bile fluid was collected for 8 h after each dosing. The maximum concentration of biliary flomoxef was significantly greater and its total excretion tended to be greater after dosing at 09:00 than 21:00 h. These results suggest the biliary excretion of flomoxef is enhanced after dosing at the beginning of the rest period in rats, as it is in humans.

The effects of different UV-B radiation intensities on morphological and biochemical characteristics in Ocimum basilicum L.

PubMed

Sakalauskaitė, Jurga; Viskelis, Pranas; Dambrauskienė, Edita; Sakalauskienė, Sandra; Samuolienė, Giedrė; Brazaitytė, Aušra; Duchovskis, Pavelas; Urbonavičienė, Dalia

2013-04-01

The effects of short-term ultraviolet B (UV-B) irradiation on sweet basil (Ocimum basilicum L. cv. Cinnamon) plants at the 3-4 leaf pair and flowering stages were examined in controlled environment growth chambers. Plants were exposed to 0 (reference), 2 and 4 kJ UV-B m(-2) day(-1) over 7 days. Exposure of basil plants to supplementary UV-B light resulted in increased assimilating leaf area, fresh biomass and dry biomass. Stimulation of physiological functions in young basil plants under either applied UV-B dose resulted in increased total chlorophyll content but no marked variation in carotenoid content. At the flowering stage the chlorophyll and carotenoid contents of basil were affected by supplementary UV-B radiation, decreasing with enhanced UV-B exposure. Both total antioxidant activity (2,2-diphenyl-1-picrylhydrazyl free radical assay) and total phenolic compound content were increased by UV-B light supplementation. Young and mature basil plants differed in their ascorbic acid content, which was dependent on UV-B dose and plant age. UV-B radiation resulted in decreased nitrate content in young basil plants (3-4 leaf pair stage). These results indicate that the application of short-exposure UV-B radiation beneficially influenced both growth parameters and biochemical constituents in young and mature basil plants. © 2012 Society of Chemical Industry.

Blue light does not impair wound healing in vitro.

PubMed

Masson-Meyers, Daniela Santos; Bumah, Violet Vakunseh; Enwemeka, Chukuka Samuel

2016-07-01

Irradiation with red or near infrared light promotes tissue repair, while treatment with blue light is known to be antimicrobial. Consequently, it is thought that infected wounds could benefit more from combined blue and red/infrared light therapy; but there is a concern that blue light may slow healing. We investigated the effect of blue 470nm light on wound healing, in terms of wound closure, total protein and collagen synthesis, growth factor and cytokines expression, in an in vitro scratch wound model. Human dermal fibroblasts were cultured for 48h until confluent. Then a linear scratch wound was created and irradiated with 3, 5, 10 or 55J/cm(2). Control plates were not irradiated. Following 24h of incubation, cells were fixed and stained for migration and fluorescence analyses and the supernatant collected for quantification of total protein, hydroxyproline, bFGF, IL-6 and IL-10. The results showed that wound closure was similar for groups treated with 3, 5 and 10J/cm(2), with a slight improvement with the 5J/cm(2) dose, and slower closure with 55J/cm(2) p<0.001). Total protein concentration increased after irradiation with 3, 5 and 10J/cm(2), reaching statistical significance at 5J/cm(2) compared to control (p<0.0001). However, hydroxyproline levels did not differ between groups. Similarly, bFGF and IL-10 concentrations did not differ between groups, but IL-6 concentration decreased progressively as fluence increased (p<0.0001). Fluorescence analysis showed viable cells regardless of irradiation fluence. We conclude that irradiation with blue light at low fluence does not impair in vitro wound healing. The significant decrease in IL-6 suggests that 470nm light is anti-inflammatory. Copyright © 2016 Elsevier B.V. All rights reserved.

Neuroprotective effects of diazoxide and its antagonism by glibenclamide in pyramidal neurons of rat hippocampus subjected to ischemia-reperfusion-induced injury.

PubMed

Zarch, Anoushiravan Vakili; Toroudi, Hamidreza Pazoki; Soleimani, Mansooreh; Bakhtiarian, Azam; Katebi, Majid; Djahanguiri, Bijan

2009-01-01

Mitochondrial ATP-sensitive potassium channel opener, diazoxide, is shown to have protective effect on the heart and brain following ischemia-reperfusion-induced injury (IR/II). However, the detailed effect of diazoxide and its antagonist on neuronal death, mitochondrial changes, and apoptosis in cerebral IR/II has not fully studied. IR/II was induced in rats by the 4-vessel occlusion model. Neuronal cell death and mitochondrial changes in CA1-CA4 pyramidal cells of the hippocampus were studied by light and electron microscopy, respectively. Apoptosis was assessed by measuring the amount of protein expressed by Bax and Bcl-2 genes. In light microscopy studies, the number of total and normal cells were increased only following 18 mg/kg of diazoxide. Lower doses (2 and 6 mg/kg) failed to change the cell numbers. All three doses of glibenclamide (1, 5, and 25 mg/kg) decreased the number of total and normal cell populations. In electron microscopy studies, different doses of diazoxide and glibenclamide prevented and aggravated the IR-induced morphological changes, respectively. Western blot analysis showed that diazoxide and glibenclamide inhibited and enhanced Bax protein expression respectively. Regarding Bcl-2 expression, only diazoxide showed a significant enhancement of gene expression. In conclusion, the results show that diazoxide can exhibit neuroprotective effects against IR/II in hippocampal regions, possibly through the opening of mitochondrial ATP-sensitive K(+) channels.

The artefacts of radiochromic film dosimetry with flatbed scanners and their causation by light scattering from radiation-induced polymers.

PubMed

Schoenfeld, Andreas A; Poppinga, Daniela; Harder, Dietrich; Doerner, Karl-Joachim; Poppe, Bjoern

2014-07-07

Optical experiments and theoretical considerations have been undertaken in order to understand the causes of the 'orientation effect' and the 'parabola effect', the artefacts impairing the desired light absorption measurement on radiochromic EBT3 films with flatbed scanners. EBT3 films exposed to doses up to 20.9 Gy were scanned with an Epson Expression 10000XL flatbed scanner in landscape and portrait orientation. The horizontally and vertically polarized light components of the scanner were determined, and another Epson Expression 10000XL flatbed scanner was disassembled to examine its optical components. The optical properties of exposed and unexposed EBT3 films were studied with incident polarized and unpolarized white light, and the transmitted red light was investigated for its polarization and scattering properties including the distribution of the scattering angles. Neutral density filters were studied for comparison. Guidance was sought from the theory of light scattering from rod-like macromolecular structures. The drastic dose-dependent variation of the transmitted total light current as function of the orientation of front and rear polarizers, interpreted by light scattering theory, shows that the radiation-induced polymerization of the monomers of EBT3 films produces light scattering oscillators preferably polarized at right angles with the coating direction of the film. The directional distribution of the scattered light is partly anisotropic, with a preferred scattering plane at right angles with the coating direction, indicating light scattering from stacks of coherently vibrating oscillators piled up along the monomer crystals. The polyester carrier film also participates in these effects. The 'orientation' and 'parabola' artefacts due to flatbed scanning of radiochromic films can be explained by the interaction of the polarization-dependent and anisotropic light scattering from exposed and unexposed EBT3 films with the quantitative difference between the scanner's horizontally and vertically polarized light supply and with the limited directional acceptance of the scanner's light recording system.

The affect of low-coherent light on microbial colony forming ability and morphology of some gram-positive and gram-negative bacteria

NASA Astrophysics Data System (ADS)

Popov, Denis E.; Tuchina, Elena S.; Chernova, Julia A.; Podshibyakin, Dmitry; Rudik, Dmitry V.; Samsonova, Maria; Gromov, Igor; Tuchin, Valery V.

2005-06-01

Gram-negative E. coli, gram-positive facultative anaerobe cocci Staphylococcus lugdensis, Micrococcus halobius, and Stomatococcus mucilaginosus as subjects of study were chosen. LEDs with spectrum maxima at 405 nm (without any exogenous sensitizer) and 660 nm (in conjunction with methylene blue) and power densities of 23 mW/cm2 and 5.7 mW/cm2 accordingly as continuous light sources were chosen. Photosensitized light's affect by methylene blue was studied on E. coli only. The original scheme of experiment set up was developed. It permits one to increase expositions quantity in each experiment for more certain trend's construction over dose curves and decrease parasite flora sowing. As a result of accomplished studies it was established that blue low-coherent light have unalike weak light's dose depending suppressing effect on cocci whereas red low-coherent light have a moderate dose-depended suppressing effect at low irradiation doses and a moderate dose-depended stimulating effect at high irradiation doses on sensitized by MeBlue E. coli. For all ofthis, but Staphylococcus morphology changes were observed.

SR-TXRF analysis of trace elements in whole blood and heart of rats: effects of irradiation with low and high doses

NASA Astrophysics Data System (ADS)

Mota, C. L.; Pickler, A.; Braz, D.; Barroso, R. C.; Mantuano, A.; Salata, C.; Ferreira-Machado, S. C.; Lau, C. C.; de Almeida, C. E.

2018-04-01

In the last decades, studies showed that the exposure to low doses of ionizing radiation of the body could sense and activate the cell signaling pathways needed to respond to any induced cellular damage. This procedure reduces cell killing compared with a single dose of high radiation dose. Damage to the vasculature can affect the function of most body organs by restricting blood flow and oxygen to tissues; however, the heart and brain are of main concern. The precise relationship between long-term health effects and low-dose exposures remain poorly understood. Biological markers are powerful tools that can be used to determine dose- response relationships and to estimate risk, especially when dealing with, the effects of low dose exposures in humans. These markers should be specific, sensitive, as well as easy and fast to quantify. Various types of biologic specimens are potential candidates for identifying biomarkers but blood has the advantage of being minimally invasive to obtain. In this study, we propose to apply total reflection X-ray fluorescence to quantify possible chemical elemental concentration (sulfer, iron, zinc, potassium and calcium) changes in blood and heart tissues of Wistar rats after total body irradiation with low (0.1 Gy) and high (2.5 Gy) doses. The fluorescence measurements were carried out at the X-ray Fluorescence beamline in the Brazilian Synchrotron Light Laboratory. The results showed that the irradiated animals with low doses have significant alterations in blood and cardiac tissue when compared with animals that received high doses of radiation. Taken together the analysis of all the elements, we can observe that the radiation induced oxidative stress may be the leading cause for alteration of the elemental level in the studied samples.

Passive dosimetry aboard the Mir Orbital Station: internal measurements.

PubMed

Benton, E R; Benton, E V; Frank, A L

2002-10-01

Passive radiation dosimeters were exposed aboard the Mir Orbital Station over a substantial portion of the solar cycle in order to measure the change in dose and dose equivalent rates as a function of time. During solar minimum, simultaneous measurements of the radiation environment throughout the habitable volume of the Mir were made using passive dosimeters in order to investigate the effect of localized shielding on dose and dose equivalent. The passive dosimeters consisted of a combination of thermoluminescent detectors to measure absorbed dose and CR-39 PNTDs to measure the linear energy transfer (LET) spectrum from charged particles of LET infinity H2O > or = 5 keV/micrometers. Results from the two detector types were then combined to yield mean total dose rate, mean dose equivalent rate, and average quality factor. Contrary to expectations, both dose and dose equivalent rates measured during May-October 1991 near solar maximum were higher than similar measurements carried out in 1996-1997 during solar minimum. The elevated dose and dose equivalent rates measured in 1991 were probably due to a combination of intense solar activity, including a large solar particle event on 9 June 1991, and the temporary trapped radiation belt created in the slot region by the solar particle event and ensuing magnetic storm of 24 March 1991. During solar minimum, mean dose and dose equivalent rates were found to vary by factors of 1.55 and 1.37, respectively, between different locations through the interior of Mir. More heavily shielded locations tended to yield lower total dose and dose equivalent rates, but higher average quality factor than did more lightly shielding locations. However, other factors such as changes in the immediate shielding environment surrounding a given detector location, changes in the orientation of the Mir relative to its velocity vector, and changes in the altitude of the station also contributed to the variation. Proton and neutron-induced target fragment secondaries, not primary galactic cosmic rays, were found to dominate the LET spectrum above 100 keV/micrometers. This indicates that in low earth orbit, trapped protons in the South Atlantic Anomaly are responsible for the major fraction of the total dose equivalent. c2002 Elsevier Science Ltd. All rights reserved.

Ultraviolet radiation cataract: dose dependence

NASA Astrophysics Data System (ADS)

Soderberg, Per G.; Loefgren, Stefan

1994-07-01

Current safety limits for cataract development after acute exposure to ultraviolet radiation (UVR) are based on experiments analyzing experimental data with a quantal, effect-no effect, dose-response model. The present study showed that intensity of forward light scattering is better described with a continuous dose-response model. It was found that 3, 30 and 300 kJ/m2UVR300nm induces increased light scattering within 6 h. For all three doses the intensity of forward light scattering was constant after 6 h. The intensity of forward light scattering was proportional to the log dose of UVR300nm. There was a slight increase of the intensity of forward light scattering on the contralateral side in animals that received 300 kJ/m2. Altogether 72 Sprague-Dawley male rats were included. Half of the rats were exposed in vivo on one side to UVR300nm. The other half was kept as a control group, receiving the same treatment as exposed rats but without delivery of UVR300nm to the eye. Subgroups of the rats received either of the three doses. Rats were sacrificed at varying intervals after the exposure. The lenses were extracted and the forward light scattering was estimated. It is concluded that intensity of forward light scattering in the lens after exposure to UVR300nm should be described with a continuous dose-reponse model.

Chlorophyll mediated photodynamic inactivation of blue laser on Streptococcus mutans

NASA Astrophysics Data System (ADS)

Astuti, Suryani Dyah; Zaidan, A.; Setiawati, Ernie Maduratna; Suhariningsih

2016-03-01

Photodynamic inactivation is an inactivation method in microbial pathogens that utilize light and photosensitizer. This study was conducted to investigate photodynamic inactivation effects of low intensity laser exposure with various dose energy on Streptococcus mutans bacteria. The photodynamic inactivation was achieved with the addition of chlorophyll as photosensitizers. To determine the survival percentage of Streptococcus mutans bacteria after laser exposure, the total plate count method was used. For this study, the wavelength of the laser is 405 nm and variables of energy doses are 1.44, 2.87, 4.31, 5.74, 7.18, and 8.61 in J/cm2. The results show that exposure to laser with energy dose of 7.18 J/cm2 has the best photodynamic inactivation with a decrease of 78% in Streptococcus

Hypericin-mediated photocytotoxic effect on HT-29 adenocarcinoma cells is reduced by light fractionation with longer dark pause between two unequal light doses.

PubMed

Sacková, Veronika; Kuliková, Lucia; Mikes, Jaromír; Kleban, Ján; Fedorocko, Peter

2005-01-01

The present study demonstrates the in vitro effect of hypericin-mediated PDT with fractionated light delivery. Cells were photosensitized with unequal light fractions separated by dark intervals (1 or 6 h). We compared the changes in viability, cell number, survival, apoptosis and cell cycle on HT-29 cells irradiated with a single light dose (12 J/cm(2)) to the fractionated light delivery (1 + 11 J/cm(2)) 24 and 48 h after photodynamic treatment. We found that a fractionated light regime with a longer dark period resulted in a decrease of hypericin cytotoxicity. Both cell number and survival were higher after light sensitization with a 6-h dark interval. DNA fragmentation occurred after a single light-dose application, but in contrast no apoptotic DNA formation was detected with a 6-h dark pause. After fractionation the percentage of cells in the G1 phase of the cell cycle was increased, while the proportion of cells in the G2 phase decreased as compared to a single light-dose application, i.e. both percentage of cells in the G1 and G2 phase of the cell cycle were near control levels. We presume that the longer dark interval after the irradiation of cells by first light dose makes them resistant to the effect of the second illumination. These findings confirm that the light application scheme together with other photodynamic protocol components is crucial for the photocytotoxicity of hypericin.

Measurements of air dose rates in and around houses in the Fukushima Prefecture in Japan after the Fukushima accident.

PubMed

Matsuda, Norihiro; Mikami, Satoshi; Sato, Tetsuro; Saito, Kimiaki

2017-01-01

Measurements of air dose rates for 192 houses in a less contaminated area (<0.5 μSv h -1 ) of the Fukushima Prefecture in Japan were conducted in both living rooms and/or bedrooms using optically stimulated luminescence (OSL) dosimeters and around the houses via a man-borne survey at intervals of several meters. The relation of the two air dose rates (inside and outside) for each house, including the background from natural radionuclides, was divided into several categories, determined by construction materials (light and heavy) and floor number, with the dose reduction factors being expressed as the ratio of the dose inside to that outside the house. For wooden and lightweight steel houses (classed as light), the dose rates inside and outside the houses showed a positive correlation and linear regression with a slope-intercept form due to the natural background, although the degree of correlation was not very high. The regression coefficient, i.e., the average dose reduction factor, was 0.38 on the first floor and 0.49 on the second floor. It was found that the contribution of natural radiation cannot be neglected when we consider dose reduction factors in less contaminated areas. The reductions in indoor dose rates are observed because a patch of ground under each house is not contaminated (this is the so-called uncontaminated effect) since the shielding capability of light construction materials is typically low. For reinforced steel-framed concrete houses (classed as heavy), the dose rates inside the houses did not show a correlation with those outside the houses due to the substantial shielding capability of these materials. The average indoor dose rates were slightly higher than the arithmetic mean value of the outdoor dose rates from the natural background because concrete acts as a source of natural radionuclides. The characteristics of the uncontaminated effect were clarified through Monte Carlo simulations. It was found that there is a great variation in air dose rates even within one house, depending on the height of the area and its closeness to the outside boundary. Measurements of outdoor dose rates required consideration of local variations depending on the environment surrounding each house. The representative value was obtained from detailed distributions of air dose rates around the house, as measured by a man-borne survey. Therefore, it is imperative to recognize that dose reduction factors fluctuate in response to various factors such as the size and shape of a house, construction materials acting as a shield and as sources, position (including height) within a room, floor number, total number of floors, and surrounding environment. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of visible light treatments on postharvest senescence of broccoli (Brassica oleracea L.).

PubMed

Büchert, Agustin M; Gómez Lobato, Maria E; Villarreal, Natalia M; Civello, Pedro M; Martínez, Gustavo A

2011-01-30

Broccoli (Brassica oleracea L.) is a rapidly perishable vegetable crop. Several postharvest treatments have been applied in order to delay de-greening. Since light has been shown to have an effect on pigment accumulation during development and darkness is known to induce senescence, the effect of continuous and periodic exposure to low-intensity white light at 22 °C on postharvest senescence of broccoli heads was assayed. Exposure to a constant dose of 12 micromol m(-2) s(-1) was selected as the most suitable treatment and was employed for subsequent experiments. During the course of the treatments, hue and L* values as well as chlorophyll content and visual observation of florets indicated an evident delay in yellowing in treated samples compared with controls. No statistically significant differences in total protein content were found, but soluble protein content was higher in treated samples. Total and reducing sugar as well as starch levels decreased during postharvest senescence, with lower values in control samples. The results of this study indicate that storage under continuous low-intensity light is an efficient and low-cost treatment that delays postharvest senescence while maintaining the quality of harvested broccoli florets. 2010 Society of Chemical Industry.

Quantifying the radiant exposure and effective dose in patients treated for actinic keratoses with topical photodynamic therapy using daylight and LED white light

NASA Astrophysics Data System (ADS)

Manley, M.; Collins, P.; Gray, L.; O'Gorman, S.; McCavana, J.

2018-02-01

Daylight photodynamic therapy (dl-PDT) is as effective as conventional PDT (c-PDT) for treating actinic keratoses but has the advantage of reducing patient discomfort significantly. Topical dl-PDT and white light-PDT (wl-PDT) differ from c-PDT by way of light sources and methodology. We measured the variables associated with light dose delivery to skin surface and influence of geometry using a radiometer, a spectral radiometer and an illuminance meter. The associated errors of the measurement methods were assessed. The spectral and spatial distribution of the radiant energy from the LED white light source was evaluated in order to define the maximum treatment area, setup and treatment protocol for wl-PDT. We compared the data with two red LED light sources we use for c-PDT. The calculated effective light dose is the product of the normalised absorption spectrum of the photosensitizer, protoporphyrin IX (PpIX), the irradiance spectrum and the treatment time. The effective light dose from daylight ranged from 3  ±  0.4 to 44  ±  6 J cm-2due to varying weather conditions. The effective light dose for wl-PDT was reproducible for treatments but it varied across the treatment area between 4  ±  0.1 J cm-2 at the edge and 9  ±  0.1 J cm-2 centrally. The effective light dose for the red waveband (615-645 nm) was 0.42  ±  0.05 J cm-2 on a clear day, 0.05  ±  0.01 J cm-2 on an overcast day and 0.9  ±  0.01 J cm-2 using the white light. This compares with 0.95  ±  0.01 and 0.84  ±  0.01 J cm-2 for c-PDT devices. Estimated errors associated with indirect determination of daylight effective light dose were very significant, particularly for effective light doses less than 5 J cm-2 (up to 83% for irradiance calculations). The primary source of error is in establishment of the relationship between irradiance or illuminance and effective dose. Use of the O’Mahoney model is recommended using a calibrated logging illuminance meter with the detector in the plane of the treatment area.

Radiation effects in LDD MOS devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodruff, R.L.; Adams, J.R.

1987-12-01

The purpose of this work is to investigate the response of lightly doped drain (LDD) n-channel transistors to ionizing radiation. Transistors were fabricated with conventional (non-LDD) and lightly doped drain (LDD) structures using both standard (non-hardened) and radiation hardened gate oxides. Characterization of the transistors began with a correlation of the total-dose effects due to 10 keV x-rays with Co-60 gamma rays. The authors find that for the gate oxides and transistor structures investigated in this work, 10 keV x-rays produce more fixed-charge guild-up in the gate oxide, and more interface charge than do Co-60 gamma rays. They determined thatmore » the radiation response of LDD transistors is similar to that of conventional (non-LDD) transistors. In addition, both standard and radiation-hardened transistors subjected to hot carrier stress before irradiation show a similar radiation response. After exposure to 1.0 x 10/sup 6/ rads(Si), non-hardened transistors show increased susceptibility to hot-carrier graduation, while the radiation-hardened transistors exhibit similar hot-carrier degradation to non-irradiated devices. The authors have demonstrated a fully-integrated radiation hardened process tht is solid to 1.0 x 10/sup 6/ rads(Si), and shows promise for achieving 1.0 x 10/sup 7/ rad(Si) total-dose capability.« less

Disparity in Cutaneous Pigmentary Response to LED vs Halogen Incandescent Visible Light: Results from a Single Center, Investigational Clinical Trial Determining a Minimal Pigmentary Visible Light Dose.

PubMed

Soleymani, Teo; Cohen, David E; Folan, Lorcan M; Okereke, Uchenna R; Elbuluk, Nada; Soter, Nicholas A

2017-11-01

Background: While most of the attention regarding skin pigmentation has focused on the effects of ultraviolet radiation, the cutaneous effects of visible light (400 to 700nm) are rarely reported. The purpose of this study was to investigate the cutaneous pigmentary response to pure visible light irradiation, examine the difference in response to different sources of visible light irradiation, and determine a minimal pigmentary dose of visible light irradiation in melanocompetent subjects with Fitzpatrick skin type III - VI. The study was designed as a single arm, non-blinded, split-side dual intervention study in which subjects underwent visible light irradiation using LED and halogen incandescent light sources delivered at a fluence of 0.14 Watts/cm2 with incremental dose progression from 20 J/cm2 to 320 J/cm2. Pigmentation was assessed by clinical examination, cross-polarized digital photography, and analytic colorimetry. Immediate, dose-responsive pigment darkening was seen with LED light exposure in 80% of subjects, beginning at 60 Joules. No pigmentary changes were seen with halogen incandescent light exposure at any dose in any subject. This study is the first to report a distinct difference in cutaneous pigmentary response to different sources of visible light, and the first to demonstrate cutaneous pigment darkening from visible LED light exposure. Our findings raise the concern that our increasing daily artificial light surroundings may have clandestine effects on skin biology.

J Drugs Dermatol. 2017;16(11):1105-1110.

Photodynamic Therapy of the Murine LM3 Tumor Using Meso-Tetra (4-N,N,N-Trimethylanilinium) Porphine.

PubMed

Colombo, L L; Juarranz, A; Cañete, M; Villanueva, A; Stockert, J C

2007-12-01

Photodynamic therapy (PDT) of cancer is based on the cytotoxicity induced by a photosensitizer in the presence of oxygen and visible light, resulting in cell death and tumor regression. This work describes the response of the murine LM3 tumor to PDT using meso-tetra (4-N,N,N-trimethylanilinium) porphine (TMAP). BALB/c mice with intradermal LM3 tumors were subjected to intravenous injection of TMAP (4 mg/kg) followed 24 h later by blue-red light irradiation (λmax: 419, 457, 650 nm) for 60 min (total dose: 290 J/cm(2)) on depilated and glycerol-covered skin over the tumor of anesthetized animals. Control (drug alone, light alone) and PDT treatments (drug + light) were performed once and repeated 48 h later. No significant differences were found between untreated tumors and tumors only treated with TMAP or light. PDT-treated tumors showed almost total but transitory tumor regression (from 3 mm to less than 1 mm) in 8/9 animals, whereas no regression was found in 1/9. PDT response was heterogeneous and each tumor showed different regression and growth delay. The survival of PDT-treated animals was significantly higher than that of TMAP and light controls, showing a lower number of lung metastasis but increased tumor-draining lymph node metastasis. Repeated treatment and reduction of tissue light scattering by glycerol could be useful approaches in studies on PDT of cancer.

Photodynamic Therapy of the Murine LM3 Tumor Using Meso-Tetra (4-N,N,N-Trimethylanilinium) Porphine

PubMed Central

Colombo, L. L.; Juarranz, A.; Cañete, M.; Villanueva, A.; Stockert, J. C.

2007-01-01

Photodynamic therapy (PDT) of cancer is based on the cytotoxicity induced by a photosensitizer in the presence of oxygen and visible light, resulting in cell death and tumor regression. This work describes the response of the murine LM3 tumor to PDT using meso-tetra (4-N,N,N-trimethylanilinium) porphine (TMAP). BALB/c mice with intradermal LM3 tumors were subjected to intravenous injection of TMAP (4 mg/kg) followed 24 h later by blue-red light irradiation (λmax: 419, 457, 650 nm) for 60 min (total dose: 290 J/cm2) on depilated and glycerol-covered skin over the tumor of anesthetized animals. Control (drug alone, light alone) and PDT treatments (drug + light) were performed once and repeated 48 h later. No significant differences were found between untreated tumors and tumors only treated with TMAP or light. PDT-treated tumors showed almost total but transitory tumor regression (from 3 mm to less than 1 mm) in 8/9 animals, whereas no regression was found in 1/9. PDT response was heterogeneous and each tumor showed different regression and growth delay. The survival of PDT-treated animals was significantly higher than that of TMAP and light controls, showing a lower number of lung metastasis but increased tumor-draining lymph node metastasis. Repeated treatment and reduction of tissue light scattering by glycerol could be useful approaches in studies on PDT of cancer. PMID:23675051

Tookad-mediated photodynamic effects on the prostate and its adjacent tissues: in vivo study in canine models

NASA Astrophysics Data System (ADS)

Huang, Zheng; Chen, Qun; Luck, David; Beckers, Jill; Blanc, Dominique; Hetzel, Fred W.

2005-04-01

Photodynamic therapy (PDT) mediated with a vascular acting photosensitizer Tookad (pd-bacteriopheophorbide), was investigated as an alternative treatment modality for prostate cancer. Tookad photodynamic effects on the prostate and its adjacent tissues were evaluated in canine models. Interstitial prostate PDT was performed by irradiating individual lobes with a diode laser (763 nm) and 1-cm cylindrical diffuser fibers at various light doses to activate the IV administered photosensitizer Tookad (1 - 2 mg/kg). The sensitivity of the adjacent tissues to Tookad-PDT was determined by superficially irradiating the surfaces of the bladder, colon, abdominal muscle and pelvic plexus with a microlens fiber at various drug/light doses. PDT effect on the prostatic urethra was evaluated by transurethral irradiation. The prostate and adjacent tissues were harvested one-week after the treatment and subjected to histopathologic examination. At one-week post interstitial prostate PDT, the animals recovered well with little or no urethral complications. PDT induced prostate lesions were characterized by marked hemorrhagic necrosis. The bladder, colon, abdominal muscle and pelvic plexus, appeared to also be sensitive to Tookad-PDT at light dose levels greater than 40 Jcm2. Urethral mucosa appeared less sensitive to Tookad-PDT. In conclusion, Tookad-mediated PDT demonstrates very strong vascular effects and can provide an effective alternative for the treatment of localized prostate cancer. Protection of the adjacent tissues should be taken into consideration in the total prostate ablation process due to their sensitivity to the Tookad-mediated PDT.

Efficient in vitro photodynamic inactivation of Candida albicans by repetitive light doses

NASA Astrophysics Data System (ADS)

Torres-Hurtado, S. A.; Ramírez Ramírez, J.; Ramos-García, R.; Ramírez-San-Juan, J. C.; Spezzia-Mazzocco, T.

2018-02-01

The aim of this study was to compare the effectiveness of Rose Bengal (RB) and Methylene Blue (MB) as photosensitizers (PS) in Photodynamic Inactivation (PDI) on planktonic cultures of Candida albicans, a well-known opportunistic pathogen. RB and MB at concentrations ranging from 0.5 to 60 μM and fluences of 10, 30, 45 and 60 J/cm2 were tested. The light sources consist of an array of 12 led diodes with 30 mW of optical power each; 490-540 nm (green light) to activate RB and 600 -650 nm (red light) to activate MB. We first optimize the in vitro PDI technique using a single light dose and the optimum PS concentration. The novelty of our approach consist in reducing further the PS concentration than the optimum obtained with a single light exposure and using smaller light fluence doses by using repetitive light exposures (two to three times). MB and RB were tested for repetitive exposures at concentrations ranging from 0.1 to 10 μM, with fluences of 3 to 20 J/cm2, doses well below than those reported previously. All experiments were done in triplicate with the corresponding controls; cells without treatment, light control and dark toxicity control. RB-PDI and MB-PDI significantly reduced the number of CFU/mL when compared to the control groups. The results showed that RB was more effective than MB for C. albicans inactivation. Thus, we show that is possible to reduce significantly the amount of PS and light fluence requirements using repetitive light doses of PDI in vitro.

Measurement of Cerenkov radiation induced by the gamma-rays of Co-60 therapy units using wavelength shifting fiber.

PubMed

Jang, Kyoung Won; Shin, Sang Hun; Kim, Seon Geun; Kim, Jae Seok; Yoo, Wook Jae; Ji, Young Hoon; Lee, Bongsoo

2014-04-21

In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%.

Comparison of flat cleaved and cylindrical diffusing fibers as treatment sources for interstitial photodynamic therapy.

PubMed

Baran, Timothy M; Foster, Thomas H

2014-02-01

For interstitial photodynamic therapy (iPDT) of bulky tumors, careful treatment planning is required in order to ensure that a therapeutic dose is delivered to the tumor, while minimizing damage to surrounding normal tissue. In clinical contexts, iPDT has typically been performed with either flat cleaved or cylindrical diffusing optical fibers as light sources. Here, the authors directly compare these two source geometries in terms of the number of fibers and duration of treatment required to deliver a prescribed light dose to a tumor volume. Treatment planning software for iPDT was developed based on graphics processing unit enhanced Monte Carlo simulations. This software was used to optimize the number of fibers, total energy delivered by each fiber, and the position of individual fibers in order to deliver a target light dose (D90) to 90% of the tumor volume. Treatment plans were developed using both flat cleaved and cylindrical diffusing fibers, based on tissue volumes derived from CT data from a head and neck cancer patient. Plans were created for four cases: fixed energy per fiber, fixed number of fibers, and in cases where both or neither of these factors were fixed. When the number of source fibers was fixed at eight, treatment plans based on flat cleaved fibers required each to deliver 7180-8080 J in order to deposit 90 J/cm(2) in 90% of the tumor volume. For diffusers, each fiber was required to deliver 2270-2350 J (333-1178 J/cm) in order to achieve this same result. For the case of fibers delivering a fixed 900 J, 13 diffusers or 19 flat cleaved fibers at a spacing of 1 cm were required to deliver the desired dose. With energy per fiber fixed at 2400 J and the number of fibers fixed at eight, diffuser fibers delivered the desired dose to 93% of the tumor volume, while flat cleaved fibers delivered this dose to 79%. With both energy and number of fibers allowed to vary, six diffusers delivering 3485-3600 J were required, compared to ten flat cleaved fibers delivering 2780-3600 J. For the same number of fibers, cylindrical diffusers allow for a shorter treatment duration compared to flat cleaved fibers. For the same energy delivered per fiber, diffusers allow for the insertion of fewer fibers in order to deliver the same light dose to a target volume.

Comparison of flat cleaved and cylindrical diffusing fibers as treatment sources for interstitial photodynamic therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baran, Timothy M., E-mail: timothy.baran@rochester.edu; Foster, Thomas H.

Purpose: For interstitial photodynamic therapy (iPDT) of bulky tumors, careful treatment planning is required in order to ensure that a therapeutic dose is delivered to the tumor, while minimizing damage to surrounding normal tissue. In clinical contexts, iPDT has typically been performed with either flat cleaved or cylindrical diffusing optical fibers as light sources. Here, the authors directly compare these two source geometries in terms of the number of fibers and duration of treatment required to deliver a prescribed light dose to a tumor volume. Methods: Treatment planning software for iPDT was developed based on graphics processing unit enhanced Montemore » Carlo simulations. This software was used to optimize the number of fibers, total energy delivered by each fiber, and the position of individual fibers in order to deliver a target light dose (D{sub 90}) to 90% of the tumor volume. Treatment plans were developed using both flat cleaved and cylindrical diffusing fibers, based on tissue volumes derived from CT data from a head and neck cancer patient. Plans were created for four cases: fixed energy per fiber, fixed number of fibers, and in cases where both or neither of these factors were fixed. Results: When the number of source fibers was fixed at eight, treatment plans based on flat cleaved fibers required each to deliver 7180–8080 J in order to deposit 90 J/cm{sup 2} in 90% of the tumor volume. For diffusers, each fiber was required to deliver 2270–2350 J (333–1178 J/cm) in order to achieve this same result. For the case of fibers delivering a fixed 900 J, 13 diffusers or 19 flat cleaved fibers at a spacing of 1 cm were required to deliver the desired dose. With energy per fiber fixed at 2400 J and the number of fibers fixed at eight, diffuser fibers delivered the desired dose to 93% of the tumor volume, while flat cleaved fibers delivered this dose to 79%. With both energy and number of fibers allowed to vary, six diffusers delivering 3485–3600 J were required, compared to ten flat cleaved fibers delivering 2780–3600 J. Conclusions: For the same number of fibers, cylindrical diffusers allow for a shorter treatment duration compared to flat cleaved fibers. For the same energy delivered per fiber, diffusers allow for the insertion of fewer fibers in order to deliver the same light dose to a target volume.« less

X-ray photoelectron and mass spectroscopic study of electron irradiation and thermal stability of polytetrafluoroethylene

NASA Technical Reports Server (NTRS)

Wheeler, Donald R.; Pepper, Stephen V.

1990-01-01

Polytetrafluoroethylene (PTFE) was subjected to 3 keV electron bombardment and then heated in vacuum to 300 C. The behavior of the material as a function of radiation dose and temperature was studied by X-ray photoelectron spectroscopy (XPS) of the surface and mass spectroscopy of the species evolved. A quantitative comparison of the radiation dose rate with that in other reported studies showed that, for a given total dose, the damage observed by XPS is greater for higher dose rates. Lightly damaged material heated to 300 C evolved saturated fluorocarbon species, whereas unsaturated fluorocarbon species evolved from heavily damaged material. After heating the heavily damaged material, those features in the XPS that were associated with damage diminished, giving the appearance that the radiation damage annealed. The apparent annealing of the radiation damage was found to be due to the covering of the network by saturated fragments that easily diffused through the decomposed material to the surface region upon heating.

Safety of two sequential whole bladder photodynamic therapy (WBPDT) treatments in the management of resistant bladder cancer

NASA Astrophysics Data System (ADS)

Nseyo, Unyime O.; Barnes, C. R.; Martin, Jessicca I.; Lamm, Donald L.; Carpenter, Cindy

2003-06-01

While 55 - 60% of newly diagnosed bladder cancers are superficial, a significant number recur as higher grade and/or stage tumors. WBPDT has been used to treat some of these recurrent superficial tumors, although its use has been associated with dose-dependent side effects. Preclinical investigation of three sequential WBPDT treatments using lower PDT dose in normal canine bladder resulted in a lack of permanent bladder contracture. Lower dose single PDT treatment has shown less durable tumor response; however, sequential WBPDT treatments with lower dose may result in durable tumor response. Five patients (4 male, 1 female), average age 65.6 (62-72 years), with recurrent or resistant superficial TCC of the bladder received two WBPDT treatments. First treatment occurred at baseline and the second treatment at 6 months. Photofrin (1.5 mg/kg) was given intravenously 48 hours prior to each cystoscopic treatment with laser light (630 nm, Coherent Lambda-Plus laser). Total light treatment doses were 1500 - 2500 Joules at baseline and 1000- 1500 Joules at 6 months. Moderate irritative bladder symptoms occurred in all patients the first week post PDT. No cases of bladder contracture have occurred. 4 of 5 patients showed no evidence of disease during the follow-up period (12 - 18 months post second treatment). One patient had a recurrence at 18 months post second treatment. Mean disease-free interval is 16.2 months. The safety of two sequential WBPDT treatments is suggested by this preliminary data. Assessment of efficacy will be possible wit a large number of patients and a longer follow-up period.

Air core detectors for Cerenkov-free scintillation dosimetry of brachytherapy β-sources.

PubMed

Eichmann, Marion; Thomann, Benedikt

2017-09-01

Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/ 106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this dosimetry system. Common approaches to correct for the Cerenkov signal are influenced by uncertainties resulting from detector positioning and calibration procedures. A different approach to avoid any correction procedure is to suppress the Cerenkov signal by replacing the solid core optical fiber with an air core light guide, previously shown for external beam therapy. In this study, the air core concept is modified and applied to the requirements of dosimetry in brachytherapy, proving its usability for measuring water energy doses in small radiation fields. Three air core detectors with different air core lengths are constructed and their performance in dosimetry for brachytherapy β-sources is compared with a standard two-fiber system, which uses a second fiber for Cerenkov correction. The detector systems are calibrated with a 90 Sr/ 90 Y secondary standard and tested for their angular dependence as well as their performance in depth dose measurements of 106 Ru/ 106 Rh sources. The signal loss relative to the standard detector increases with increasing air core length to a maximum value of 58.3%. At the same time, however, the percentage amount of Cerenkov light in the total signal is reduced from at least 12.1% to a value below 1.1%. There is a linear correlation between induced dose and measured signal current. The air core detectors determine the dose rates for 106 Ru/ 106 Rh sources without any form of correction for the Cerenkov signal. The air core detectors show advantages over the standard two-fiber system especially when measuring in radiation fields with high dose gradients. They can be used as simple one-fiber systems and allow for an almost Cerenkov-free scintillation dosimetry of brachytherapy β-sources. © 2017 American Association of Physicists in Medicine.

Dose-response relationship for light intensity and ocular and electroencephalographic correlates of human alertness

NASA Technical Reports Server (NTRS)

Cajochen, C.; Zeitzer, J. M.; Czeisler, C. A.; Dijk, D. J.

2000-01-01

Light can elicit both circadian and acute physiological responses in humans. In a dose response protocol men and women were exposed to illuminances ranging from 3 to 9100 lux for 6.5 h during the early biological night after they had been exposed to <3 lux for several hours. Light exerted an acute alerting response as assessed by a reduction in the incidence of slow-eye movements, a reduction of EEG activity in the theta-alpha frequencies (power density in the 5-9 Hz range) as well as a reduction in self-reported sleepiness. This alerting response was positively correlated with the degree of melatonin suppression by light. In accordance with the dose response function for circadian resetting and melatonin suppression, the responses of all three indices of alertness to variations in illuminance were consistent with a logistic dose response curve. Half of the maximum alerting response to bright light of 9100 lux was obtained with room light of approximately 100 lux. This sensitivity to light indicates that variations in illuminance within the range of typical, ambient, room light (90-180 lux) can have a significant impact on subjective alertness and its electrophysiologic concomitants in humans during the early biological night.

Assessment of patient dose and radiogenic risks during endoscopic retrograde cholangiopancreatography.

PubMed

Sulieman, A; Elzaki, M; Alkhorayef, M; Babikir, E; Abuzaid, M; Dalton, A; Bradley, D

2016-11-01

Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive technique that has been used for over 30 years in the diagnosis and management of pancreaticobiliary disorders. The objectives of this study were to evaluate the patient entrance surface air kerma doses (ESAK) and estimate the organ and effective doses during ERCP in three hospitals in Khartoum. A total of 55 patients were examined in three hospitals in Khartoum state, Sudan. Calibrated thermoluinescent dosimeters (TLD) were used to measure patients' ESAK. Organ and effective doses were estimated using National Radiological Protection Board (NRPB) software. The overall mean of ESAK for all ERCP procedures was 42.4mGy. The mean patient ESAK in Fedail (A), Soba (B) and Ibn sena (C) hospitals were 26.7mGy, 26.0mGy and 72.4mGy, respectively. The effective doses in three hospitals were 1.60, 1.56 and 2.67mSv in that order and the overall mean effective dose was 1.94mSv. Patient radiation doses vary widely among the hospitals. Patient ESAK is low compared to previous studies in the light of the current practice. Patient dose was decreased significantly in the last two decades. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of optimal drug dose and light dose index to achieve minimally invasive focal ablation of localised prostate cancer using WST11-vascular-targeted photodynamic (VTP) therapy.

PubMed

Moore, Caroline M; Azzouzi, Abel-Rahmene; Barret, Eric; Villers, Arnauld; Muir, Gordon H; Barber, Neil J; Bott, Simon; Trachtenberg, John; Arumainayagam, Nimalan; Gaillac, Bertrand; Allen, Clare; Schertz, Avigdor; Emberton, Mark

2015-12-01

To determine the optimal drug and light dose for prostate ablation using WST11 (TOOKAD Soluble) for vascular-targeted photodynamic (VTP) therapy in men with low-risk prostate cancer. In all, 42 men with low-risk prostate cancer were enrolled in the study but two who underwent anaesthesia for the procedure did not receive the drug or light dose. Thus, 40 men received a single dose of 2, 4 or 6 mg/kg WST11 activated by 200 J/cm light at 753 nm. WST11 was given as a 10-min intravenous infusion. The light dose was delivered using cylindrical diffusing fibres within hollow plastic needles positioned in the prostate using transrectal ultrasonography (TRUS) guidance and a brachytherapy template. Magnetic resonance imaging (MRI) was used to assess treatment effect at 7 days, with assessment of urinary function (International Prostate Symptom Score [IPSS]), sexual function (International Index of Erectile Function [IIEF]) and adverse events at 7 days, 1, 3 and 6 months after VTP. TRUS-guided biopsies were taken at 6 months. In all, 39 of the 40 treated men completed the follow-up. The Day-7 MRI showed maximal treatment effect (95% of the planned treatment volume) in men who had a WST11 dose of 4 mg/kg, light dose of 200 J/cm and light density index (LDI) of >1. In the 12 men treated with these parameters, the negative biopsy rate was 10/12 (83%) at 6 months, compared with 10/26 (45%) for the men who had either a different drug dose (10 men) or an LDI of <1 (16). Transient urinary symptoms were seen in most of the men, with no significant difference in IPSS score between baseline and 6 months after VTP. IIEF scores were not significantly different between baseline and 6 months after VTP. Treatment with 4 mg/kg TOOKAD Soluble activated by 753 nm light at a dose of 200 J/cm and an LDI of >1 resulted in treatment effect in 95% of the planned treatment volume and a negative biopsy rate at 6 months of 10/12 men (83%). © 2014 The Authors BJU International © 2014 BJU International Published by John Wiley & Sons Ltd.

Monte Carlo modeling of in vivo protoporphyrin IX fluorescence and singlet oxygen production during photodynamic therapy for patients presenting with superficial basal cell carcinomas

NASA Astrophysics Data System (ADS)

Valentine, Ronan M.; Brown, C. Tom A.; Moseley, Harry; Ibbotson, Sally; Wood, Kenny

2011-04-01

We present protoporphyrin IX (PpIX) fluorescence measurements acquired from patients presenting with superficial basal cell carcinoma during photodynamic therapy (PDT) treatment, facilitating in vivo photobleaching to be monitored. Monte Carlo (MC) simulations, taking into account photobleaching, are performed on a three-dimensional cube grid, which represents the treatment geometry. Consequently, it is possible to determine the spatial and temporal changes to the origin of collected fluorescence and generated singlet oxygen. From our clinical results, an in vivo photobleaching dose constant, β of 5-aminolaevulinic acid-induced PpIX fluorescence is found to be 14 +/- 1 J/cm2. Results from our MC simulations suggest that an increase from our typical administered treatment light dose of 75-150 J/cm2 could increase the effective PDT treatment initially achieved at a depth of 2.7-3.3 mm in the tumor, respectively. Moreover, this increase reduces the surface PpIX fluorescence from 0.00012 to 0.000003 of the maximum value recorded before treatment. The recommendation of administrating a larger light dose, which advocates an increase in the treatment time after surface PpIX fluorescence has diminished, remains valid for different sets of optical properties and therefore should have a beneficial outcome on the total treatment effect.

Differences in the response of wheat, soybean and lettuce to reduced blue radiation

NASA Technical Reports Server (NTRS)

Dougher, T. A.; Bugbee, B.

2001-01-01

Although many fundamental blue light responses have been identified, blue light dose-response curves are not well characterized. We studied the growth and development of soybean, wheat and lettuce plants under high-pressure sodium (HPS) and metal halide (MH) lamps with yellow filters creating five fractions of blue light. The blue light fractions obtained were < 0.1, 2 and 6% under HPS lamps, and 6, 12 and 26% under MH lamps. Studies utilizing both lamp types were done at two photosynthetic photon flux levels, 200 and 500 mumol m-2 s-1 under a 16 h photoperiod. Phytochrome photoequilibria was nearly identical among treatments. The blue light effect on dry mass, stem length, leaf area, specific leaf area and tillering/branching was species dependent. For these parameters, wheat did not respond to blue light, but lettuce was highly sensitive to blue light fraction between 0 and 6% blue. Soybean stem length decreased and leaf area increased up to 6% blue, but total dry mass was unchanged. The blue light fraction determined the stem elongation response in soybean, whereas the absolute amount of blue light determined the stem elongation response in lettuce. The data indicate that lettuce growth and development requires blue light, but soybean and wheat may not.

Amphetamine self-administration in light and moderate drinkers.

PubMed

Stanley, Matthew D; Poole, Mégan M; Stoops, William W; Rush, Craig R

2011-03-01

Light and moderate drinkers respond differently to the effects of abused drugs, including stimulants such as amphetamine. The purpose of this study was to determine whether light and moderate drinkers differ in their sensitivity to the reinforcing and subjective effects of d-amphetamine. We hypothesized that moderate drinkers (i.e., participants that reported consuming at least seven alcohol-containing beverages per week) would be more sensitive to the reinforcing and positive subject-rated effects of d-amphetamine than light drinkers. Data from four studies that employed similar d-amphetamine self-administration procedures and subject-rated drug-effect measures were included in the analysis. Light (n = 17) and moderate (n = 16) drinkers sampled placebo, low (8 to 10 mg), and high (16 to 20 mg) doses of oral d-amphetamine administered in eight capsules. Following sampling sessions, participants worked for a maximum of eight capsules, each containing 12.5% of the previously sampled dose, on a modified progressive-ratio schedule of reinforcement. Both active doses of d-amphetamine functioned as a reinforcer in the moderate drinkers, while only the high dose did so in the light drinkers. The moderate drinkers worked for significantly more capsules that contained the high dose of d-amphetamine than did the light drinkers. d-Amphetamine produced prototypical stimulant-like subjective effects (e.g., dose-dependent increases in ratings of Good Effects; Like Drug and Willing to Take Again). Moderate drinkers reported significantly greater subjective effects than the light drinkers. These results are consistent with those from previous laboratory experiments and suggest that moderate alcohol consumption may increase vulnerability to the abuse-related effects of stimulants. Copyright © 2010 by the Research Society on Alcoholism.

Optical fibres in the radiation environment of CERN

NASA Astrophysics Data System (ADS)

Guillermain, E.

2017-11-01

CERN, the European Organization for Nuclear Research (in Geneva, Switzerland), is home to a complex scientific instrument: the 27-kilometre Large Hadron Collider (LHC) collides beams of high-energy particles at close to the speed of light. Optical fibres are widely used at CERN, both in surface areas (e.g. for inter-building IT networks) and in the accelerator complex underground (e.g. for cryogenics, vacuum, safety systems). Optical fibres in the accelerator are exposed to mixed radiation fields (mainly composed of protons, pions, neutrons and other hadrons, gamma rays and electrons), with dose rates depending on the particular installation zone, and with radiation levels often significantly higher than those encountered in space. In the LHC and its injector chain radiation levels range from relatively low annual doses of a few Gy up to hundreds of kGy. Optical fibres suffer from Radiation Induced Attenuation (RIA, expressed in dB per unit length) that affect light transmission and which depends on the irradiation conditions (e.g. dose rate, total dose, temperature). In the CERN accelerator complex, the failure of an optical link can affect the proper functionality of control or monitoring systems and induce the interruption of the accelerator operation. The qualification of optical fibres for installation in critical radiation areas is therefore crucial. Thus, all optical fibre types installed in radiation areas at CERN are subject to laboratory irradiation tests, in order to evaluate their RIA at different total dose and dose rates. This allows the selection of the appropriate optical fibre type (conventional or radiation resistant) compliant with the requirements of each installation. Irradiation tests are performed in collaboration with Fraunhofer INT (irradiation facilities and expert team in Euskirchen, Germany). Conventional off-the-shelf optical fibres can be installed for optical links exposed to low radiation levels (i.e. annual dose typically below few kGy). Nevertheless, the conventional optical fibres must be carefully qualified as a spread in RIA of factor 10 is observed among optical fibres of different types and dopants. In higher radiation areas, special radiation resistant optical fibres are installed. For total dose above 1 kGy, the RIA of these special optical fibres is at least 10 times lower than the conventional optical fibres RIA at same irradiation conditions. 2400 km of these special radiation resistant optical fibres were recently procured at CERN. As part of this procurement process, a quality assurance plan including the irradiation testing of all 65 produced batches was set up. This presentation will review the selection process of the appropriate optical fibre types to be installed in the radiation environment of CERN. The methodology for choosing the irradiation parameters for the laboratory tests will be discussed together with an overview of the RIA of different optical fibre types under several irradiation conditions.

Effects of low-dose light-emitting-diode therapy in combination with water bath for atopic dermatitis in NC/Nga mice.

PubMed

Kim, Chang-Hyun; Cheong, Kyung Ah; Lim, Won Suk; Park, Hyung-Moo; Lee, Ai-Young

2016-01-01

Light-emitting diode (LED) phototherapy and water bath therapy have beneficial effect on atopic dermatitis (AD)-like skin disease. However, not all current treatments work well and alternative therapies are need. The contribution of combination therapy with low-dose 850 nm LED and water bath was investigated on dermatophagoides farina (Df)-induced dermatitis in NC/Nga mice. Low-dose LED (10, 15, and 20 J/cm(2) ) irradiation, water bath (36 ± 1°C) were administered separately and together to the Df-induced NC/Nga mice in acrylic jar once a day for 2 weeks. Combined therapy with low-dose LED therapy and water bath therapy significantly ameliorated the development of AD-like skin lesions. These effects were correlated with the suppression of total IgE, NO, histamine, and Th2-mediated immune responses. Furthermore, combination therapy significantly reduced the infiltration of inflammatory cells and the induction of thymic stromal lymphopoietin (TSLP) in the skin lesions. The beneficial therapeutic effects of this combination therapy might regulate by the inhibition of various immunological responses including Th2-mediated immune responses, inflammatory mediators such as IgE, histamine, and NO, as well as inflammatory cells. The combination therapy of LED and water bath might be used as an efficacious, safe, and steroid-free alternative therapeutic strategy for the treatment of AD. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

SU-F-J-56: The Connection Between Cherenkov Light Emission and Radiation Absorbed Dose in Proton Irradiated Phantoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darafsheh, A; Kassaee, A; Finlay, J

Purpose: Range verification in proton therapy is of great importance. Cherenkov light follows the photon and electron energy deposition in water phantom. The purpose of this study is to investigate the connection between Cherenkov light generation and radiation absorbed dose in a water phantom irradiated with proton beams. Methods: Monte Carlo simulation was performed by employing FLUKA Monte Carlo code to stochastically simulate radiation transport, ionizing radiation dose deposition, and Cherenkov radiation in water phantoms. The simulations were performed for proton beams with energies in the range 50–600 MeV to cover a wide range of proton energies. Results: The mechanismmore » of Cherenkov light production depends on the initial energy of protons. For proton energy with 50–400 MeV energy that is below the threshold (∼483 MeV in water) for Cherenkov light production directly from incident protons, Cherenkov light is produced mainly from the secondary electrons liberated as a result of columbic interactions with the incident protons. For proton beams with energy above 500 MeV, in the initial depth that incident protons have higher energy than the Cherenkov light production threshold, the light has higher intensity. As the slowing down process results in lower energy protons in larger depths in the water phantom, there is a knee point in the Cherenkov light curve vs. depth due to switching the Cherenkov light production mechanism from primary protons to secondary electrons. At the end of the depth dose curve the Cherenkov light intensity does not follow the dose peak because of the lack of high energy protons to produce Cherenkov light either directly or through secondary electrons. Conclusion: In contrast to photon and electron beams, Cherenkov light generation induced by proton beams does not follow the proton energy deposition specially close to the end of the proton range near the Bragg peak.« less

Photodynamic dosimetry in the treatment of periodontitis

NASA Astrophysics Data System (ADS)

Andersen, Roger C.; Loebel, Nicolas G.; Andersen, Dane M.

2009-06-01

Photodynamic therapy has been demonstrated to effectively kill human periopathogens in vitro. However, the translation of in vitro work to in vivo clinical efficacy has been difficult due to the number of variables present in any given patient. Parameters such as photosensitizer concentration, duration of light therapy and amount of light delivered to the target tissue all play a role in the dose response of PDT in vivo. In this 121 patient study we kept all parameters the same except for light dose which was delivered at either 150 mW or 220 mW. This clearly demonstrated the clinical benefits of a higher light dose in the treatment of periodontitis.

Topical methyl-aminolevulinate photodynamic therapy using red light-emitting diode light for treatment of multiple actinic keratoses: A randomized, double-blind, placebo-controlled study.

PubMed

Pariser, David; Loss, Robert; Jarratt, Michael; Abramovits, William; Spencer, James; Geronemus, Roy; Bailin, Philip; Bruce, Suzanne

2008-10-01

The use of light-emitting diode light offers practical advantages in photodynamic therapy (PDT) with topical methyl-aminolevulinate (MAL) for management of actinic keratoses (AK). We sought to evaluate the efficacy of MAL PDT using red light-emitting diode light. We conducted a multicenter, double-blind, randomized study. A total of 49 patients with 363 AK lesions had 16.8% MAL cream applied under occlusion for 3 hours, and 47 patients with 360 AK lesions had vehicle cream similarly applied. The lesions were then illuminated (630 nm, light dose 37 J/cm2) with repeated treatment 1 week later. Complete lesion and patient (all lesions showing complete response) response rates were evaluated 3 months after last treatment. MAL PDT was superior (P<.0001) to vehicle PDT with respect to lesion complete response (86.2% vs 52.2%, odds ratio 6.9 [95% confidence interval 4.7-10.3]) and patient complete response (59.2% vs 14.9%, odds ratio 13.2 [95% confidence interval 4.1-43.1]). The study population may not be representative of all patients with AK. MAL PDT using red light-emitting diode light is an appropriate treatment alternative for multiple AK lesions.

A Phase I Study of Light Dose for Photodynamic Therapy (PDT) Using 2-[1-hexyloxyethyl]-2 devinyl Pyropheophorbide-a (HPPH) for Treatment of Non-small Cell Carcinoma in situ or Non-small Cell Microinvasive Bronchogenic Carcinoma. A Dose Ranging Study

PubMed Central

Dhillon, Samjot Singh; Demmy, Todd L.; Yendamuri, Sai; Loewen, Gregory; Nwogu, Chukwumere; Cooper, Michele; Henderson, Barbara W.

2015-01-01

Introduction We report a phase I trial of photodynamic therapy (PDT) of carcinoma-insitu (CIS) and microinvasive cancer (MIC) of the central airways with the photosensitizer (PS) 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH). HPPH has the advantage of minimal general phototoxicity over the commonly used PS porfimer sodium (Photofrin®). Methods The objectives of this study were 1) to determine the maximally tolerated light dose at a fixed PS dose and 2) to gain initial insight into the effectiveness of this treatment approach. Seventeen patients with 21 CIS/MIC lesions were treated with HPPH with light dose escalation starting from 75 J/cm2 to 85, 95,125, and 150 J/cm2 respectively. Follow-up bronchoscopy for response assessment was done at one and six months, respectively. Results The rate of pathological complete response (CR) was 82.4% (14/17 evaluable lesions; 14 patients) at one-month and 72.7% (8/11 lesions; 8 patients) at 6 months. Only 4 patients developed mild skin erythema. One of the three patients in 150 J/cm2 light dose group experienced a serious adverse event. This patient had respiratory distress due to mucus plugging, which precipitated cardiac ischemia. Two additional patients treated subsequently at this light dose had no adverse events. The third sixth patient in this dose group was not recruited and the study was terminated because of delays in HPPH supply. However, given the observed serious adverse event, it is recommended that the light dose not exceed 125J/cm2. Conclusions PDT with HPPH can be safely used for the treatment of CIS/MIC of the airways, with potential effectiveness comparable to that reported for porfimer sodium in earlier studies. PMID:26718878

SU-F-207-01: Comparison of Beam Characteristics and Organ Dose From Four Commercial Multidetector Computed Tomography Scanners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohno, T; Araki, F

2015-06-15

Purpose: To compare dosimetric properties and patient organ doses from four commercial multidetector CT (MDCT) using Monte Carlo (MC) simulation based on the absorbed dose measured using a Farmer chamber and cylindrical water phantoms according to AAPM TG-111. Methods: Four commercial MDCT were modeled using the GMctdospp (IMPS, Germany) based on the EGSnrc user code. The incident photon spectrum and bowtie filter for MC simulations were determined so that calculated values of aluminum half-value layer (Al-HVL) and off-center ratio (OCR) profile in air agreed with measured values. The MC dose was calibrated from absorbed dose measurements using a Farmer chambermore » and cylindrical water phantoms. The dose distributions of head, chest, and abdominal scan were calculated using patient CT images and mean organ doses were evaluated from dose volume histograms. Results: The HVLs at 120 kVp of Brilliance, LightSpeed, Aquilion, and SOMATOM were 9.1, 7.5, 7.2, and 8.7 mm, respectively. The calculated Al-HVLs agreed with measurements within 0.3%. The calculated and measured OCR profiles agreed within 5%. For adult head scans, mean doses for eye lens from Brilliance, LightSpeed, Aquilion, and SOMATOM were 21.7, 38.5, 47.2 and 28.4 mGy, respectively. For chest scans, mean doses for lung from Brilliance, LightSpeed, Aquilion, and SOMATOM were 21.1, 26.1, 35.3 and 24.0 mGy, respectively. For adult abdominal scans, the mean doses for liver from Brilliance, LightSpeed, Aquilion, and SOMATOM were 16.5, 21.3, 22.7, and 18.0 mGy, respectively. The absorbed doses increased with decreasing Al-HVL. The organ doses from Aquilion were two greater than those from Brilliance in head scan. Conclusion: MC dose distributions based on absorbed dose measurement in cylindrical water phantom are useful to evaluate individual patient organ doses.« less

Photobiomodulation of distinct lineages of human dermal fibroblasts: a rational approach towards the selection of effective light parameters for skin rejuvenation and wound healing

NASA Astrophysics Data System (ADS)

Mignon, Charles; Uzunbajakava, Natallia E.; Raafs, Bianca; Moolenaar, Mitchel; Botchkareva, Natalia V.; Tobin, Desmond J.

2016-03-01

Distinct lineages of human dermal fibroblasts play complementary roles in skin rejuvenation and wound healing, which makes them a target of phototherapy. However, knowledge about differential responses of specific cell lineages to different light parameters and moreover the actual molecular targets remain to be unravelled. The goal of this study was to investigate the impact of a range of parameters of light on the metabolic activity, collagen production, and cell migration of distinct lineages of human dermal fibroblasts. A rational approach was used to identify parameters with high therapeutic potential. Fibroblasts exhibited both inhibitory and cytotoxic change when exposed to a high dose of blue and cyan light in tissue culture medium containing photo-reactive species, but were stimulated by high dose red and near infrared light. Cytotoxic effects were eliminated by refreshing the medium after light exposure by removing potential ROS formed by extracellular photo-reactive species. Importantly, distinct lineages of fibroblasts demonstrated opposite responses to low dose blue light treatment when refreshing the medium after exposure. Low dose blue light treatment also significantly increased collagen production by papillary fibroblasts; high dose significantly retarded closure of the scratch wound without signs of cytotoxicity, and this is likely to have involved effects on both cell migration and proliferation. We recommend careful selection of fibroblast subpopulations and their culture conditions, a systematic approach in choosing and translating treatment parameters, and pursuit of fundamental research on identification of photoreceptors and triggered molecular pathways, while seeking effective parameters to address different stages of skin rejuvenation and wound healing.

Light delivery over extended time periods enhances the effectiveness of photodynamic therapy.

PubMed

Seshadri, Mukund; Bellnier, David A; Vaughan, Lurine A; Spernyak, Joseph A; Mazurchuk, Richard; Foster, Thomas H; Henderson, Barbara W

2008-05-01

The rate of energy delivery is a principal factor determining the biological consequences of photodynamic therapy (PDT). In contrast to conventional high-irradiance treatments, recent preclinical and clinical studies have focused on low-irradiance schemes. The objective of this study was to investigate the relationship between irradiance, photosensitizer dose, and PDT dose with regard to treatment outcome and tumor oxygenation in a rat tumor model. Using the photosensitizer HPPH (2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide), a wide range of PDT doses that included clinically relevant photosensitizer concentrations was evaluated. Magnetic resonance imaging and oxygen tension measurements were done along with the Evans blue exclusion assay to assess vascular response, oxygenation status, and tumor necrosis. In contrast to high-incident laser power (150 mW), low-power regimens (7 mW) yielded effective tumor destruction. This was largely independent of PDT dose (drug-light product), with up to 30-fold differences in photosensitizer dose and 15-fold differences in drug-light product. For all drug-light products, the duration of light treatment positively influenced tumor response. Regimens using treatment times of 120 to 240 min showed marked reduction in signal intensity in T2-weighted magnetic resonance images at both low (0.1 mg/kg) and high (3 mg/kg) drug doses compared with short-duration (6-11 min) regimens. Significantly greater reductions in pO(2) were observed with extended exposures, which persisted after completion of treatment. These results confirm the benefit of prolonged light exposure, identify vascular response as a major contributor, and suggest that duration of light treatment (time) may be an important new treatment variable.

Light Delivery Over Extended Time Periods Enhances the Effectiveness of Photodynamic Therapy

PubMed Central

Seshadri, Mukund; Bellnier, David A.; Vaughan, Lurine A.; Spernyak, Joseph A.; Mazurchuk, Richard; Foster, Thomas H.; Henderson, Barbara W.

2009-01-01

Purpose The rate of energy delivery is a principal factor determining the biological consequences of photodynamic therapy (PDT). In contrast to conventional high irradiance treatments, recent preclinical and clinical studies have focused on low irradiance schemes. The objective of this study was to investigate the relationship between irradiance, photosensitizer dose and PDT dose with regard to treatment outcome and tumor oxygenation in a rat tumor model. Experimental Design Using the photosensitizer HPPH (2-[1-hexyloxyethyl]-2 devinyl pyropheophorbide), a wide range of PDT doses that included clinically relevant photosensitizer concentrations were evaluated. Magnetic resonance imaging (MRI) and oxygen tension measurements were performed along with the Evans blue exclusion assay to assess vascular response, oxygenation status and tumor necrosis. Results In contrast to high incident laser power (150 mW), low power regimens (7 mW) yielded effective tumor destruction. This was largely independent of PDT dose (drug-light product), with up to 30-fold differences in photosensitizer dose and 15-fold differences in drug-light product. For all drug-light products, the duration of light treatment positively influenced tumor response. Regimens utilizing treatment times of 120–240 mins showed marked reduction in signal intensity in T2-weighted MR images at both low (0.1 mg/kg) and high (3 mg/kg) drug doses compared to short duration (6–11 mins) regimens. Significantly greater reductions in pO2 were observed with extended exposures, which persisted after completion of treatment. Conclusions These results confirm the benefit of prolonged light exposure, identify vascular response as a major contributor and suggest that duration of light treatment (time) may be an important new treatment parameter. PMID:18451247

Preliminary evidence that light through the eyelids can suppress melatonin and phase shift dim light melatonin onset

PubMed Central

2012-01-01

Background A previous study reported a method for measuring the spectral transmittance of individual human eyelids. A prototype light mask using narrow-band “green” light (λmax = 527 nm) was used to deliver light through closed eyelids in two within-subjects studies. The first study investigated whether an individual-specific light dose could suppress melatonin by 40% through the closed eyelid without disrupting sleep. The light doses were delivered at three times during the night: 1) beginning (while subjects were awake), 2) middle (during rapid eye movement (REM) sleep), and 3) end (during non-REM sleep). The second study investigated whether two individual-specific light doses expected to suppress melatonin by 30% and 60% and delivered through subjects’ closed eyelids before the time of their predicted minimum core body temperature would phase delay the timing of their dim light melatonin onset (DLMO). Findings Compared to a dark control night, light delivered through eyelids suppressed melatonin by 36% (p = 0.01) after 60-minute light exposure at the beginning, 45% (p = 0.01) at the middle, and 56% (p < 0.0001) at the end of the night. In the second study, compared to a dark control night, melatonin was suppressed by 25% (p = 0.03) and by 45% (p = 0.009) and circadian phase, as measured by DLMO, was delayed by 17 minutes (p = 0.03) and 71 minutes (ns) after 60-minute exposures to light levels 1 and 2, respectively. Conclusions These studies demonstrate that individual-specific doses of light delivered through closed eyelids can suppress melatonin and phase shift DLMO and may be used to treat circadian sleep disorders. PMID:22564396

Preliminary evidence that light through the eyelids can suppress melatonin and phase shift dim light melatonin onset.

PubMed

Figueiro, Mariana G; Rea, Mark S

2012-05-07

A previous study reported a method for measuring the spectral transmittance of individual human eyelids. A prototype light mask using narrow-band "green" light (λmax = 527 nm) was used to deliver light through closed eyelids in two within-subjects studies. The first study investigated whether an individual-specific light dose could suppress melatonin by 40% through the closed eyelid without disrupting sleep. The light doses were delivered at three times during the night: 1) beginning (while subjects were awake), 2) middle (during rapid eye movement (REM) sleep), and 3) end (during non-REM sleep). The second study investigated whether two individual-specific light doses expected to suppress melatonin by 30% and 60% and delivered through subjects' closed eyelids before the time of their predicted minimum core body temperature would phase delay the timing of their dim light melatonin onset (DLMO). Compared to a dark control night, light delivered through eyelids suppressed melatonin by 36% (p = 0.01) after 60-minute light exposure at the beginning, 45% (p = 0.01) at the middle, and 56% (p < 0.0001) at the end of the night. In the second study, compared to a dark control night, melatonin was suppressed by 25% (p = 0.03) and by 45% (p = 0.009) and circadian phase, as measured by DLMO, was delayed by 17 minutes (p = 0.03) and 71 minutes (ns) after 60-minute exposures to light levels 1 and 2, respectively. These studies demonstrate that individual-specific doses of light delivered through closed eyelids can suppress melatonin and phase shift DLMO and may be used to treat circadian sleep disorders.

Ascending Single-Dose, Double-Blind, Placebo-Controlled Safety Study of Noribogaine in Opioid-Dependent Patients.

PubMed

Glue, Paul; Cape, Gavin; Tunnicliff, Donna; Lockhart, Michelle; Lam, Fred; Hung, Noelyn; Hung, C Tak; Harland, Sarah; Devane, Jane; Crockett, R S; Howes, John; Darpo, Borje; Zhou, Meijian; Weis, Holger; Friedhoff, Lawrence

2016-11-01

Ibogaine is a psychoactive substance that may reduce opioid withdrawal symptoms. This was the first clinical trial of noribogaine, ibogaine's active metabolite, in patients established on methadone opioid substitution therapy (OST). In this randomized, double-blind, placebo-controlled single ascending-dose study, we evaluated the safety, tolerability, and pharmacokinetics of noribogaine in 27 patients seeking to discontinue methadone OST who had been switched to morphine during the previous week. Noribogaine doses were 60, 120, or 180 mg (n = 6/dose level) or matching placebo (n = 3/dose level). Noribogaine was well tolerated. The most frequent treatment-emergent adverse events were noneuphoric changes in light perception ∼1 hour postdose, headache, and nausea. Noribogaine had dose-linear increases for AUC and C max and was slowly eliminated (mean t 1/2 range, 24-30 hours). There was a concentration-dependent increase in QTcI (0.17 ms/ng/mL), with the largest observed mean effect of ∼16, 28, and 42 milliseconds in the 60-, 120-, and 180-mg groups, respectively. Noribogaine showed a nonstatistically significant trend toward decreased total score in opioid withdrawal ratings, most notably at the 120-mg dose; however, the study design may have confounded evaluations of time to resumption of OST. Future exposure-controlled multiple-dose noribogaine studies are planned that will address these safety and design issues. © 2016, The American College of Clinical Pharmacology.

[Protective effect of emodin pretreatment in young rats with intrahepatic cholestasis].

PubMed

Xiong, Xiao-Li; Yan, Su-Qi; Qin, Huan; Zhou, Li-Shan; Zhang, Ling-Ling; Jiang, Zhi-Xia; Ding, Yan

2016-02-01

To investigate the protective effect of emodin in young rats with intrahepatic cholestasis. A total of 120 young Sprague-Dawley rats were randomly divided into control, model, and high-, medium-, and low-dose emodin groups, with 24 rats in each group. The rats in the control and model groups were given sodium carboxymethyl cellulose solution by gavage, while the other groups were given different doses of emodin solution by gavage. On the 5th day of experiment, alpha-naphthylisothiocyanate (ANIT, 50 mg/kg) was applied by gavage to establish the model of intrahepatic cholestasis in all groups except the control group. At 24, 48, and 72 hours after gavage, 8 rats in each group were sacrificed. Colorimetry was used to measure the serum levels of total bilirubin (TBIL), direct bilirubin (DBIL), total bile acid (TBA), alkaline phosphatase (ALP), gamma glutamyl transpeptidase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in each group, and hematoxylin-eosin staining was applied to observe the morphological changes of the liver under a light microscope at different time points. Compared with the control group, the model group had significantly increased serum levels of TBIL, DBIL, TBA, ALP, GGT, ALT, and AST at the 24-hour, 48-hour, and 72-hour time points (P<0.01). In the model group, the serum levels of TBIL, DBIL, TBA, ALT, and AST showed varying degrees of increase at 48 hours after establishment of model, compared with the values at 24 and 72 hours (P<0.05). At 24, 48, and 72 hours, the high-, medium-, and low-dose emodin groups had varying degrees of reductions in the serum levels of TBIL and TBA compared with the model group (P<0.05); the high- and low-dose emodin groups had significantly increased serum levels of TBA compared with the medium-dose emodin group (P<0.05). The model group had the most severe pathological changes at 48 hours. Compared with the model group, the high-, medium-, and low-dose emodin groups showed certain improvement in pathological changes of the liver at each time point, and the medium-dose emodin group had better improvement compared with the high- and low-dose emodin groups. Emodin can effectively improve ANIT-induced intrahepatic cholestasis in young rats, and medium-dose emodin shows the best effect.

UV light-induced survival response in a highly radiation-resistant isolate of the Moraxella-acinetobacter group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, L.C.; Thompson, T.L.; Maxcy, R.B.

1982-02-01

A highly radiation-resistant member of the Moraxella-Acinetobacter group, isolate 4, obtained from meat, was studied to determine the effect of preexposure to UV radiation on subsequent UV light resistance. Cultures that were preexposed to UV light and incubated for a short time in plate count broth exhibited increased survival of a UV light challenge dose. This response was inhibited in the presence of chloramphenicol. Frequencies of mutation to streptomycin, trimethoprim, and sulfanilamide resistance remained the same after the induction of this survival response and were not altered by treatment with mutagens, with the exception of mutation to streptomycin resistance aftermore » ..gamma..-irradiation or nitrosoguanidine or methyl methane sulfonate treatment. The results indicated that isolate 4 has a UV light-inducible UV light resistance mechanism which is not associated with increased mutagenesis. The characteristics of the radiation resistance response in this organism are similar to those of certain other common food contaminants. Therefore, considered as part of the total microflora of meat, isolate 4 and the other radiation-resistant Moraxella-Acinetobacter isolates should not pose unique problems in a proposed radappertizaton process.« less

Inhomogeneity in optical properties of rat brain: a study for LLLT dosimetry

NASA Astrophysics Data System (ADS)

Sousa, Marcelo V. P.; Prates, Renato; Kato, Ilka T.; Sabino, Caetano P.; Yoshimura, Tania M.; Suzuki, Luis C.; Magalhães, Ana C.; Yoshimura, Elisabeth M.; Ribeiro, Martha S.

2013-03-01

Over the last few years, low-level light therapy (LLLT) has shown an incredible suitability for a wide range of applications for central nervous system (CNS) related diseases. In this therapeutic modality light dosimetry is extremely critical so the study of light propagation through the CNS organs is of great importance. To better understand how light intensity is delivered to the most relevant neural sites we evaluated optical transmission through slices of rat brain point by point. We experimented red (λ = 660 nm) and near infrared (λ = 808 nm) diode laser light analyzing the light penetration and distribution in the whole brain. A fresh Wistar rat (Rattus novergicus) brain was cut in sagittal slices and illuminated with a broad light beam. A high-resolution digital camera was employed to acquire data of transmitted light. Spatial profiles of the light transmitted through the sample were obtained from the images. Peaks and valleys in the profiles show sites where light was less or more attenuated. The peak intensities provide information about total attenuation and the peak widths are correlated to the scattering coefficient at that individual portion of the sample. The outcomes of this study provide remarkable information for LLLT dose-dependent studies involving CNS and highlight the importance of LLLT dosimetry in CNS organs for large range of applications in animal and human diseases.

Comparison of Blue and White Lamp Light with Sunlight for Daylight-Mediated, 5-ALA Photodynamic Therapy, in vivo.

PubMed

Marra, Kayla; LaRochelle, Ethan P; Chapman, M Shane; Hoopes, P Jack; Lukovits, Karina; Maytin, Edward V; Hasan, Tayyaba; Pogue, Brian W

2018-04-16

Daylight-mediated photodynamic therapy (d-PDT) as a treatment for actinic keratosis (AK) is an increasingly common technique due to a significant reduction in pain, leading to better patient tolerability. While past studies have looked at different light sources and delivery methods, this study strives to provide equivalent PpIX-weighted light doses with the hypothesis that artificial light sources could be equally as effective as natural sunlight if their PpIX-weighted fluences were equalized. Normal mouse skin was used as the model to compare blue LED light, metal halide white light and natural sunlight, with minimal incubation time between topical ALA application and the onset of light delivery. A total PpIX-weighted fluence of 20 J eff cm -2 was delivered over 2 h, and the efficacy of response was quantified using three acute bioassays for PDT damage: PpIX photobleaching, Stat3 crosslinking and quantitative histopathology. These bioassays indicated blue light was slightly inferior to both sunlight and white light, but that the latter two were not significantly different. The results suggest that metal halide white light could be a reasonable alternative to daylight PDT, which should allow a more controlled treatment that is independent of weather and yet should have similar response rates with limited pain during treatment. © 2018 The American Society of Photobiology.

Accelerated Optical Projection Tomography Applied to In Vivo Imaging of Zebrafish

PubMed Central

Correia, Teresa; Yin, Jun; Ramel, Marie-Christine; Andrews, Natalie; Katan, Matilda; Bugeon, Laurence; Dallman, Margaret J.; McGinty, James; Frankel, Paul; French, Paul M. W.; Arridge, Simon

2015-01-01

Optical projection tomography (OPT) provides a non-invasive 3-D imaging modality that can be applied to longitudinal studies of live disease models, including in zebrafish. Current limitations include the requirement of a minimum number of angular projections for reconstruction of reasonable OPT images using filtered back projection (FBP), which is typically several hundred, leading to acquisition times of several minutes. It is highly desirable to decrease the number of required angular projections to decrease both the total acquisition time and the light dose to the sample. This is particularly important to enable longitudinal studies, which involve measurements of the same fish at different time points. In this work, we demonstrate that the use of an iterative algorithm to reconstruct sparsely sampled OPT data sets can provide useful 3-D images with 50 or fewer projections, thereby significantly decreasing the minimum acquisition time and light dose while maintaining image quality. A transgenic zebrafish embryo with fluorescent labelling of the vasculature was imaged to acquire densely sampled (800 projections) and under-sampled data sets of transmitted and fluorescence projection images. The under-sampled OPT data sets were reconstructed using an iterative total variation-based image reconstruction algorithm and compared against FBP reconstructions of the densely sampled data sets. To illustrate the potential for quantitative analysis following rapid OPT data acquisition, a Hessian-based method was applied to automatically segment the reconstructed images to select the vasculature network. Results showed that 3-D images of the zebrafish embryo and its vasculature of sufficient visual quality for quantitative analysis can be reconstructed using the iterative algorithm from only 32 projections—achieving up to 28 times improvement in imaging speed and leading to total acquisition times of a few seconds. PMID:26308086

Ketamine as an Adjunct to Opioids for Acute Pain in the Emergency Department: A Randomized Controlled Trial.

PubMed

Bowers, Karen J; McAllister, Kelly B; Ray, Meredith; Heitz, Corey

2017-06-01

This study had five objectives: 1) to measure and compare total opioid use and number of opioid doses in patients treated with opioids versus ketamine in conjunction with opioids; 2) to measure pain scores up to 2 hours after presentation in the ED patient with pain, comparing standard opioid pain control to ketamine in conjunction with opioids; 3) to compare patient satisfaction with pain control using opioids alone versus ketamine in conjunction with opioids; 4) to monitor and compare side effects in patients treated with opioids versus ketamine in conjunction with opioids; and 5) to identify effect variation between different subgroups of patients, with the purpose of focusing future research. We hypothesized that low-dose ketamine, compared to placebo, as an adjunctive treatment to opioids would result in better pain control over 2 hours and greater patient satisfaction with pain control; further, this protocol will result in a lower opioid dosage over 2 hours. This was a randomized, double-blinded, placebo-controlled trial at a single academic emergency department evaluating the use of ketamine versus placebo in conjunction with opioids for moderate to severe pain. Subjects with a continued high level of pain after an initial dose of opioid analgesia were randomized to receive either 0.1 mg/kg ketamine or placebo prior to protocol-based dosing of additional opioid analgesia, if required. Over 120 minutes, subjects were assessed for pain level (0-10), satisfaction with pain control (0-4), side effects, sedation level, and need for additional pain medication. Total opioid dose, including the initial dose, was compared between groups. Sixty-three subjects were randomized to the placebo group and 53 to the ketamine group. No significant differences were found in demographics between the groups. Patients receiving ketamine reported lower pain scores over 120 minutes than patients receiving placebo (p = 0.015). Total opioid dose was lower in the ketamine group (mean ± SD = 9.95 ± 4.83 mg) compared to placebo (mean ± SD = 12.81 ± 6.81 mg; p = 0.02). Satisfaction did not differ between groups. Fewer patients in the ketamine group required additional opioid doses. More patients reported light-headedness and dizziness in the ketamine group. Ketamine, as an adjunct to opioid therapy, was more effective at reducing pain over 120 minutes and resulted in a lower total opioid dose as well as fewer repeat doses of analgesia. More side effects were reported in the ketamine group (51% vs. 19%), but the side effect profile appears tolerable. © 2017 by the Society for Academic Emergency Medicine.

Evaluation of photon irradiation treatment upon calcium content of ribs of Wistar rats using micro-XRF

NASA Astrophysics Data System (ADS)

Nogueira, Liebert Parreiras; Barroso, Regina Cély; de Almeida, André Pereira; Braz, Delson; de Almeida, Carlos Eduardo; Salata, Camila; Andrade, Cherley Borba; da Silva, Claudia Marcello

2012-05-01

Therapeutic doses of radiation have been shown to have deleterious consequences on bone health. Among the treatment strategies used for breast cancer treatment, the most used are radiotherapy and chemotherapy. Radiotherapy may be given to destroy the cancer cells using high-dose x-rays. Protocols vary considerably, but generally whole body irradiation totals from 10 to 15 Gy, whereas local therapy totals from 40 to 70 Gy. In clinical practice, the quantitative evaluation of bone tissue relies on measurements of bone mineral density values, which are closely associated with the risk of osteoporotic fracture. Improved survivorship rates of cancer patients receiving radiotherapy increase the importance of understanding the mechanisms and long-term effects of radiation-induced bone loss. In this work, we investigated the variation on calcium distribution in ribs of female Wistar rats (Rattus norvegicus) submitted to photon irradiation with a single dose of 20 Gy. The determination of the calcium distribution was performed using synchrotron radiation microfluorescence (SR-μXRF) at the X-ray Fluorescence beamline at Brazilian Synchrotron Light Laboratory (LNLS). Animals were irradiated using the linear accelerator Varian® (CLINAC 2100) at the University Centre for Cancer Control of the State University of Rio de Janeiro (CUCC/UERJ). The total dose delivered was 20 Gy. The animals were about three months old and weighting about 200g. They were distributed into two groups (seven per group): control (did not receive any treatment) and irradiated (submitted to irradiation procedure) groups. Results showed that calcium content decreased within the dorsal ribs of rats submitted to radiotherapy in comparison to the control group.

A Phase I Study of Light Dose for Photodynamic Therapy Using 2-[1-Hexyloxyethyl]-2 Devinyl Pyropheophorbide-a for the Treatment of Non-Small Cell Carcinoma In Situ or Non-Small Cell Microinvasive Bronchogenic Carcinoma: A Dose Ranging Study.

PubMed

Dhillon, Samjot Singh; Demmy, Todd L; Yendamuri, Sai; Loewen, Gregory; Nwogu, Chukwumere; Cooper, Michele; Henderson, Barbara W

2016-02-01

We report a phase I trial of photodynamic therapy (PDT) of carcinoma in situ (CIS) and microinvasive cancer (MIC) of the central airways with the photosensitizer (PS) 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH). HPPH has the advantage of minimal general phototoxicity over the commonly used photosensitizer porfimer sodium (Photofrin; Pinnacle Biologics, Chicago, IL). The objectives of this study were (1) to determine the maximally tolerated light dose at a fixed photosensitizer dose and (2) to gain initial insight into the effectiveness of this treatment approach. Seventeen patients with 21 CIS/MIC lesions were treated with HPPH with light dose escalation starting from 75 J/cm2 and increasing to 85, 95,125, and 150 J/cm2 respectively. Follow-up bronchoscopy for response assessment was performed at 1 and 6 months, respectively. The rate of pathological complete response (CR) was 82.4% (14 of 17 evaluable lesions; 14 patients) at 1 month and 72.7% (8/11 evaluable lesions; 8 patients) at 6 months. Only four patients developed mild skin erythema. One of the three patients in the 150 J/cm2 light dose group experienced a serious adverse event. This patient had respiratory distress caused by mucus plugging, which precipitated cardiac ischemia. Two additional patients treated subsequently at this light dose had no adverse events. The sixth patient in this dose group was not recruited and the study was terminated because of delays in HPPH supply. However, given the observed serious adverse event, it is recommended that the light dose does not exceed 125 J/cm2. PDT with HPPH can be safely used for the treatment of CIS/MIC of the airways, with potential effectiveness comparable to that reported for porfimer sodium in earlier studies. Copyright © 2015 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Late Dose-Response Effects of Prenatal Cocaine Exposure on Newborn Neurobehavioral Performance

PubMed Central

Tronick, Edward Z.; Frank, Deborah A.; Cabral, Howard; Mirochnick, Mark; Zuckerman, Barry

2008-01-01

Objective To determine in a representative sample of full-term urban newborns of English-speaking mothers whether an immediate or late dose-response effect could be demonstrated between prenatal cocaine exposure and newborn neurobehavioral performance, controlling for confounding factors. Methods The Neonatal Behavioral Assessment Scale (NBAS) was administered by masked examiners to a total sample of 251 clinically healthy, full-term infants at 2 days and/or 17 days. Three in utero cocaine exposure groups were defined: heavily exposed (n = 44, >75th percentile self-reported days of use during pregnancy and/or >75th percentile of meconium benzoylecognine concentration); lightly exposed (n = 79, less than both 75th percentiles); and unexposed (n = 101, no positive biological or self-report marker). At the 3-week examination there were 38 heavily exposed, 73 lightly exposed, and 94 unexposed infants. Controlling for infant birth weight, gestational age, infant age at the time of examination, mothers’ age, perinatal risk, obstetric medication, and alcohol, marijuana, and cigarette use, a regression analysis evaluated the effects of levels of cocaine exposure on NBAS performance. Results No neurobehavioral effects of exposure on the newborn NBAS cluster scores or on the qualifier scores were found when confounders were controlled for at 2 to 3 days of age. At 3 weeks, after controlling for covariates, a significant dose effect was observed, with heavily exposed infants showing poorer state regulation and greater excitability. Conclusions These findings demonstrate specific dose-related effects of cocaine on 3-week neurobehavioral performance, particularly for the regulation of arousal, which was not observed in the first few days of life. PMID:8668416

Characterizing the discoloration of EBT3 films in solar UV A+B measurement using red LED

NASA Astrophysics Data System (ADS)

Omar, Ahmad Fairuz; Osman, Ummi Shuhada; Tan, Kok Chooi

2017-09-01

This research article proposes an alternative method to measure the discoloration or the color changes of EBT3 films due to exposure by solar ultraviolet (UV A+B) dose. Common methods to measure the color changes of EBT3 are through imaging technique measured by flatbed scanner and through absorbance spectroscopy measured by visible spectrometer. The research presented in this article measure the color changes of EBT3 through simplified optical system using the combination of light emitting diode (LED) as the light source and photodiode as the detector. In this research, 50 pieces of Gafchromic EBT3 films were prepared with the dimension of 3 cm x 2 cm. Color of the films changed from light green to dark green based on the total accumulated UV dose (mJ/cm2) by each film that depends on the duration of exposure, irradiance level (mW/cm2) and condition of the sky. The exposed films were then taken to the laboratory for its color measurement using absorbance spectroscopy technique and using newly developed simplified optical instrument using LED-photodiode. Results from spectroscopy technique indicate that wavelength within red region exhibit better response in term of linearity and responsivity towards the colors of EBT3 films. Wavelength of 626 nm was then selected as the peak emission wavelength for LED-photodiode absorbance system. UV dose measurement using LEDphotodiode system produced good result with coefficient of determination, R2 of 0.97 and root mean square of error, RMSE of 431.82 mJ/cm2 while comparatively, similar wavelength but analyzed from spectroscopy dataset produced R2 of 0.988 and RMSE of 268.94 mJ/cm2.

Synchrotron X-ray microbeam dosimetry with a 20 micrometre resolution scintillator fibre-optic dosimeter.

PubMed

Archer, James; Li, Enbang; Petasecca, Marco; Stevenson, Andrew; Livingstone, Jayde; Dipuglia, Andrew; Davis, Jeremy; Rosenfeld, Anatoly; Lerch, Michael

2018-05-01

Cancer is one of the leading causes of death worldwide. External beam radiation therapy is one of the most important modalities for the treatment of cancers. Synchrotron microbeam radiation therapy (MRT) is a novel pre-clinical therapy that uses highly spatially fractionated X-ray beams to target tumours, allowing doses much higher than conventional radiotherapies to be delivered. A dosimeter with a high spatial resolution is required to provide the appropriate quality assurance for MRT. This work presents a plastic scintillator fibre optic dosimeter with a one-dimensional spatial resolution of 20 µm, an improvement on the dosimeter with a resolution of 50 µm that was demonstrated in previous work. The ability of this probe to resolve microbeams of width 50 µm has been demonstrated. The major limitations of this method were identified, most notably the low-light signal resulting from the small sensitive volume, which made valley dose measurements very challenging. A titanium-based reflective paint was used as a coating on the probe to improve the light collection, but a possible effect of the high-Z material on the probes water-equivalence has been identified. The effect of the reflective paint was a 28.5 ± 4.6% increase in the total light collected; it did not affect the shape of the depth-dose profile, nor did it explain an over-response observed when used to probe at low depths, when compared with an ionization chamber. With improvements to the data acquisition, this probe design has the potential to provide a water-equivalent, inexpensive dosimetry tool for MRT.

Curcumin uptake enhancement using low dose light illumination during incubation in Candida albicans

NASA Astrophysics Data System (ADS)

Romano, Renan A.; Pratavieira, Sebastião.; da Silva, Ana P.; Kurachi, Cristina; Bagnato, Vanderlei S.; Guimarães, Francisco E. G.

2017-07-01

A new PDI protocol is presented in this study. C. albicans cells pre-illuminated with a low dose light demonstrated an increase of curcumin uptake when compared to dark incubation, leading to a higher PDI efficacy.

Successful treatment with 308-nm monochromatic excimer light and subsequent tacrolimus 0.03% ointment in refractory plasma cell cheilitis.

PubMed

Yoshimura, Kazuhiro; Nakano, Shunji; Tsuruta, Daisuke; Ohata, Chika; Hashimoto, Takashi

2013-06-01

Plasma cell cheilitis is a chronic inflammatory disease that presents with erythema, erosions, ulcers and occasional nodules within the mucosa, including the lips. It is histopathologically characterized by dense plasma cell infiltration in the lamina propria of the mucous membranes. Several treatments for plasma cell cheilitis have been reported, including topical steroids, topical antibiotics or topical tacrolimus. However, 308-nm monochromatic excimer light (MEL) has never been reported as a treatment option, while it was reported to be very effective in treating erosive oral lichen planus. We report a 62-year-old man who had chronic plasma cell cheilitis on the lower lip, which was refractory to topical and systemic corticosteroid. The lesion and severe pain were significantly improved by the treatment with nine sessions of 308-nm MEL twice per week with a total dose of 1120 mJ/cm(2). However, the lesion gradually worsened after treatment frequency was reduced to once per month. Subsequent tacrolimus 0.03% ointment cleared the lesion completely in a month and no recurrence was observed a year later. Refractory plasma cell cheilitis and concomitant severe pain quickly responded to 308-nm MEL when administrated twice per week. Because the long interval between each MEL treatment seemed ineffective to improve the lesion, appropriate frequency and adequate total dose of MEL treatment may be necessary for a successful treatment. © 2013 Japanese Dermatological Association.

Investigation on physiological and clinical effects of different light sources in TMJ photobiomodulation therapy

NASA Astrophysics Data System (ADS)

Kamenoff, J.

2017-02-01

Introduction Laser light Electromagnetic energy has some typical properties for discussions on laser irradiation abilities to control the acute and chronic disorders in TMJ. Material and Methods During the last six years we have been completed well controlled clinical trials based on the criteria of the American Academy of orofacial pain. The study over the 600 patients (300 women and 300 men), mean age of 47 years have been developed. Patients have been selected on the main clinical sign of TMJ pain and have been divided into four main groups according to the type of PDT method. Based on the action spectra, various wavelengths have been used for TMJ Photodynamic Therapy. Constant dose and time of exposition, as well as various range of frequencies have been applied. In this way the Laser biostimulation response has been directly proportional to the total energy dose, depending of light intensity. Physiological and clinical effects of the followed "active regions"- 660 - 680, 760 - 780, 810 - 830 and 904 - 987 nm have been valued by method of comparative analysis. Methods applied: LLLT - TENS - red surface laser acupuncture (LA), PIPBM - LA, Laser bioenergetics approach, Complex therapeutic program (CTP). Results evaluation will be demonstrated by comparative digital ortopantomograph analysis, EEG brain maps, VAS, a metric analysis of the level of the maximum active Mandible opening and EPST through electrophysiological signal evaluation of the patient's body.

Photodynamic therapy and fluorescent diagnostics of skin cancer with radochlorine and photosense: comparing efficacy and toxicity

NASA Astrophysics Data System (ADS)

Vakulovskaya, Elena G.; Kemov, Yuriy V.; Zalevsky, Igor D.; Reshetnikov, Andrew V.; Umnova, Loubov V.; Vorozhcsov, Georgiu N.

2004-06-01

Photodynamic therapy (PDT) and fluorescent diagnostics (FD) with Radaclorine (RadaPharma, Russia) (RC) have been provided in 32 patients with T1-4 stage basal cell carcinoma (BCC) and in 81 patients with Photsense. Pharmacocynetic studies with detecting the borders of tumor growth and intensity of accumulation of photosensizers in tumor, normal tissues and visualization have been done by Spectral-fluorescent Complex and spectranalyser LESA-01 (He-Ne-laser, λ=633nm). We've got fluorescence of all tumors and additional fluorescence zones were found, cytological verification of BCC was got in most of cases. The fluorescent signs of RC in normal skin were found till 5 days after injection. As a source of light for PDT we used simeconductive lasers: Milon - λ = 660+2nm, light dose was 200-300 J/cm2 and Biospec (λ+672+2nm), multiple laser surface and interstitial irradiation was performed 24 hours after PS injection with total light dose till 400-600 J/cm2. 2 months after PDT with RC complete response (CR) in 65.6% of cases, partial response-in 34.4% of cases. The efficacy of PDT with PS was higher (CR-84.0%, PR-14.8%). Our experience show pronounced efficacy of PDT with RC for BCC without side effects and very short skin toxicity.

Calculated and TLD-based absorbed dose estimates for I-131-labeled 3F8 monoclonal antibody in a human neuroblastoma xenograft nude mouse model.

PubMed

Ugur, O; Scott, A M; Kostakoglu, L; Hui, T E; Masterson, M E; Febo, R; Sgouros, G; Rosa, E; Mehta, B M; Fisher, D R

1995-01-01

Preclinical evaluation of the therapeutic potential of radiolabeled antibodies is commonly performed in a xenografted nude mouse model. To assess therapeutic efficacy it is important to estimate the absorbed dose to the tumor and normal tissues of the nude mouse. The current study was designed to accurately measure radiation does to human neuroblastoma xenografts and normal organs in nude mice treated with I-131-labeled 3F8 monoclonal antibody (MoAb) against disialoganglioside GD2 antigen. Absorbed dose estimates were obtained using two different approaches: (1) measurement with teflon-imbedded CaSO4:Dy mini-thermoluminescent dosimeters (TLDs) and (2) calculations using mouse S-factors. The calculated total dose to tumor one week after i.v. injection of the 50 microCi I-131-3F8 MoAb was 604 cGy. The corresponding decay corrected and not corrected TLD measurements were 109 +/- 9 and 48.7 +/- 3.4 cGy respectively. The calculated to TLD-derived dose ratios for tumor ranged from 6.1 at 24 h to 5.5 at 1 week. The light output fading rate was found to depend upon the tissue type within which the TLDs were implanted. The decay rate in tumor, muscle, subcutaneous tissue and in vitro, were 9.5, 5.0, 3.7 and 0.67% per day, respectively. We have demonstrated that the type of tissue in which the TLD was implanted strongly influenced the in vivo decay of light output. Even with decay correction, a significant discrepancy was observed between MIRD-based calculated and CaSO4:Dy mini-TLD measured absorbed doses. Batch dependence, pH of the tumor or other variables associated with TLDs which are not as yet well known may account for this discrepancy.

Evaluation of the hepatoprotective effect of combination between hinokiflavone and Glycyrrhizin against CCl4 induced toxicity in rats.

PubMed

Abdel-Kader, Maged S; Abulhamd, Ashraf T; Hamad, Abubaker M; Alanazi, Abdullah H; Ali, Rizwan; Alqasoumi, Saleh I

2018-05-01

Liver diseases are one of the fatal syndromes due to the vital role of the liver. Most of the effective treatment of liver conditions are of natural origin. Silymarin (SI) is the standard drug used for treatment of impaired liver functions. Two natural compounds possessing promising liver protection and with different chemical structures namely; the bioflavonoid hinokiflavone (HF) isolated from Junipers phoenicea family Cupressaceae and the sweet saponin Glycyrrhizin (GL) present in  Glycyrrhiza glabra  (liquorice) were selected for the current study. Since the two compounds are of different nature, they may act by different mechanisms and express synergistic effect. Combination of the two compounds using to dose levels were challenged with single doses of HF, GL and SI as well. The comparison was monitored via measuring serum biochemical parameters including, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltranspeptidase (GGT), alkaline phosphatase (ALP) and total bilirubin, tissue parameters such as MDA, NP-SH and TP, histopathological study using light and electron microscope. Protective effect on kidney was also monitored histopathologically and biochemically through observing the levels of LDH, creatinine, creatinine-kinase, urea and uric acid. The combinations of HF and GL showed protective effect more than the used single doses of HF and GL alone. However, SI was superior to the used combination in the two used doses in all the measured parameters. The liver and kidney cells appearance under normal and electron microscope showed that SI treated groups showed almost normal cells with slight toxic signs. Cells from group treated with the higher doses of the combination of HF and GL showed slight signs of intoxication under light and electron microscope indicating good level of protection. Although the combination of HF and GL expressed good protection in the higher dose, however, the combination did not exceed the protective effect of SI.

Single-event and total-dose effects in geo-stationary transfer orbit during solar-activity maximum period measured by the Tsubasa satellite

NASA Astrophysics Data System (ADS)

Koshiishi, H.; Kimoto, Y.; Matsumoto, H.; Goka, T.

The Tsubasa satellite developed by the Japan Aerospace Exploration Agency was launched in Feb 2002 into Geo-stationary Transfer Orbit GTO Perigee 500km Apogee 36000km and had been operated well until Sep 2003 The objective of this satellite was to verify the function of commercial parts and new technologies of bus-system components in space Thus the on-board experiments were conducted in the more severe radiation environment of GTO rather than in Geo-stationary Earth Orbit GEO or Low Earth Orbit LEO The Space Environment Data Acquisition equipment SEDA on board the Tsubasa satellite had the Single-event Upset Monitor SUM and the DOSimeter DOS to evaluate influences on electronic devices caused by radiation environment that was also measured by the particle detectors of the SEDA the Standard DOse Monitor SDOM for measurements of light particles and the Heavy Ion Telescope HIT for measurements of heavy ions The SUM monitored single-event upsets and single-event latch-ups occurred in the test sample of two 64-Mbit DRAMs The DOS measured accumulated radiation dose at fifty-six locations in the body of the Tsubasa satellite Using the data obtained by these instruments single-event and total-dose effects in GTO during solar-activity maximum period especially their rapid changes due to solar flares and CMEs in the region from L 1 1 through L 11 is discussed in this paper

Treatment planning and dose analysis for interstitial photodynamic therapy of prostate cancer

NASA Astrophysics Data System (ADS)

Davidson, Sean R. H.; Weersink, Robert A.; Haider, Masoom A.; Gertner, Mark R.; Bogaards, Arjen; Giewercer, David; Scherz, Avigdor; Sherar, Michael D.; Elhilali, Mostafa; Chin, Joseph L.; Trachtenberg, John; Wilson, Brian C.

2009-04-01

With the development of new photosensitizers that are activated by light at longer wavelengths, interstitial photodynamic therapy (PDT) is emerging as a feasible alternative for the treatment of larger volumes of tissue. Described here is the application of PDT treatment planning software developed by our group to ensure complete coverage of larger, geometrically complex target volumes such as the prostate. In a phase II clinical trial of TOOKAD vascular targeted photodynamic therapy (VTP) for prostate cancer in patients who failed prior radiotherapy, the software was used to generate patient-specific treatment prescriptions for the number of treatment fibres, their lengths, their positions and the energy each delivered. The core of the software is a finite element solution to the light diffusion equation. Validation against in vivo light measurements indicated that the software could predict the location of an iso-fluence contour to within approximately ±2 mm. The same software was used to reconstruct the treatments that were actually delivered, thereby providing an analysis of the threshold light dose required for TOOKAD-VTP of the post-irradiated prostate. The threshold light dose for VTP-induced prostate damage, as measured one week post-treatment using contrast-enhanced MRI, was found to be highly heterogeneous, both within and between patients. The minimum light dose received by 90% of the prostate, D90, was determined from each patient's dose-volume histogram and compared to six-month sextant biopsy results. No patient with a D90 less than 23 J cm-2 had complete biopsy response, while 8/13 (62%) of patients with a D90 greater than 23 J cm-2 had negative biopsies at six months. The doses received by the urethra and the rectal wall were also investigated.

WE-DE-201-07: Measurement of Real-Time Dose for Tandem and Ovoid Brachytherapy Procedures Using a High Precision Optical Fiber Radiation Detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belley, MD; Current Address Rhode Island Hospital, Providence, RI; Faught, A

Purpose: Development of a novel on-line dosimetry tool is needed to move toward patient-specific quality assurance measurements for Ir-192 HDR brachytherapy to verify accurate dose delivery to the intended location. This work describes the development and use of a nano-crystalline yttrium oxide inorganic scintillator based optical-fiber detector capable of acquiring real-time high-precision dose measurements during tandem and ovoid (T&O) gynecological (GYN) applicator Ir-192 HDR brachytherapy procedures. Methods: An optical-fiber detector was calibrated by acquiring light output measurements in liquid water at 3, 5, 7, and 9cm radial source-detector-distances from an Ir-192 HDR source. A regression model was fit to themore » data to describe the relative light output per unit dose (TG-43 derived) as a function of source-detector-distance. Next, the optical-fiber detector was attached to a vaginal balloon fixed to a Varian Fletcher-Suit-Delclos-style applicator (to mimic clinical setup), and localized by acquiring high-resolution computed tomography (CT) images. To compare the physical point dose to the TPS calculated values (TG-43 and Acuros-BV), a phantom measurement was performed, by submerging the T&O applicator in a liquid water bath and delivering a treatment template representative of a clinical T&O procedure. The fiber detector collected scintillation signal as a function of time, and the calibration data was applied to calculate both real-time dose rate, and cumulative dose. Results: Fiber cumulative dose values were 100.0cGy, 94.3cGy, and 348.9cGy from the tandem, left ovoid, and right ovoid dwells, respectively (total of 443.2cGy). A plot of real time dose rate during the treatment was also acquired. The TPS values at the fiber location were 458.4cGy using TG-43, and 437.6cGy using Acuros-BV calculated as Dm,m (per TG-186). Conclusion: The fiber measured dose value agreement was 3% vs TG-43 and −1% vs Acuros-BV. This fiber detector opens up new possibilities for performing patient-specific quality assurance for Ir-192 HDR GYN procedures. Funding from Coulter Foundation, Duke Bio-medical Engineering. Company is being created around the detector technology. Duke holds patents on the technology.« less

Complete erasing of ghost images on computed radiography plates and role of deeply trapped electrons

NASA Astrophysics Data System (ADS)

Ohuchi-Yoshida, Hiroko; Kondo, Yasuhiro

2011-12-01

Computed radiography (CR) plates made of europium-doped Ba(Sr)FBr(I) were simultaneously exposed to filtered ultraviolet light and visible light in order to erase ghost images, i.e., latent image that is unerasable with visible light (LIunVL) and reappearing one, which are particularly observed in plates irradiated with a high dose and/or cumulatively over-irradiated. CR samples showing LIunVLs were prepared by irradiating three different types of CR plates (Agfa ADC MD10, Kodak Directview Mammo EHRM2, and Fuji ST-VI) with 50 kV X-ray beams in the dose range 8.1 mGy-8.0 Gy. After the sixth round of simultaneous 6 h exposures to filtered ultraviolet light and visible light, all the LIunVLs in the three types of CR plates were erased to the same level as in an unirradiated plate and no latent images reappeared after storage at 0 °C for 14 days. With conventional exposure to visible light, LIunVLs consistently remained in all types of CR plates irradiated with higher doses of X-rays and latent images reappeared in the Agfa M10 plates after storage at 0 °C. Electrons trapped in deep centers cause LIunVLs and they can be erased by simultaneous exposures to filtered ultraviolet light and visible light. To study electrons in deep centers, the absorption spectra were examined in all types of irradiated CR plates by using polychromatic ultraviolet light from a deep-ultraviolet lamp. It was found that deep centers showed a dominant peak in the absorption spectra at around 324 nm for the Agfa M10 and Kodak EHRM2 plates, and at around 320 nm for the Fuji ST-VI plate, in each case followed by a few small peaks. The peak heights were dose-dependent for all types of CR samples, suggesting that the number of electrons trapped in deep centers increases with the irradiation dose.

Efficacy and safety of ascending doses of praziquantel against Schistosoma haematobium infection in preschool-aged and school-aged children: a single-blind randomised controlled trial.

PubMed

Coulibaly, Jean T; Panic, Gordana; Yapi, Richard B; Kovač, Jana; Barda, Beatrice; N'Gbesso, Yves K; Hattendorf, Jan; Keiser, Jennifer

2018-06-01

Despite decades of experience with praziquantel treatment in school-aged children (SAC) and adults, we still face considerable knowledge gaps relevant to the successful treatment of preschool-aged children (PSAC). This study aimed to assess the efficacy and safety of escalating praziquantel dosages in PSAC infected with Schistosoma haematobium. We conducted a randomised, dose-finding trial in PSAC (2-5 years) and as comparator a cohort of SAC (6-15 years) infected with S. haematobium in Côte d'Ivoire. A total of 186 PSAC and 195 SAC were randomly assigned to 20, 40 or 60 mg/kg praziquantel or placebo. The nature of the dose-response relationship in terms of cure rate (CR) was the primary objective. Egg reduction rate (ERR) and tolerability were secondary outcomes. CRs and ERRs were assessed using triplicate urine filtration over 3 consecutive days. Available-case analysis was performed including all participants with primary endpoint data. A total of 170 PSAC and 174 SAC received treatment. Almost 90% of PSAC and three quarters of SAC were lightly infected with S. haematobium. Follow-up data were available for 157 PSAC and 166 SAC. In PSAC, CRs of praziquantel were 85.7% (30/35), 78.0% (32/41) and 68.3% (28/41) at 20, 40 and 60 mg/kg and 47.5% (19/40) for placebo. In SAC, CRs were 10.8% for placebo (4/37), 55.6% for 20 mg/kg (25/45), 68.3% for 40 mg/kg (28/41) and 60.5% for 60 mg/kg (26/43). ERRs based on geometric means ranged between 96.5% (60 mg/kg) and 98.3% (20 mg/kg) in PSAC and between 97.6% (20 mg/kg and 60 mg/kg) and 98.6% (40 mg/kg) in SAC. Adverse events were mild and transient. Praziquantel revealed dose-independent efficacy against light infections of S. haematobium. Over the dose range tested, praziquantel displayed a ceiling effect with the highest response for 20 mg/kg in PSAC. In SAC maximum efficacy was obtained with 40 mg/kg praziquantel. Further investigations are required in children with moderate to heavy infections. This trial is registered with International Standard Randomised Controlled Trial Number ISRCTN15280205 .

[Effect of polychromatic visible light combined with infrared radiation on tumorigenicity of murine hepatoma cells and their sensitivity to lytic activity of natural killers].

PubMed

Filatova, N A; Kniazev, N A; Kosheverova, V V; Shatrova, A N; Samoĭlova, K A

2013-01-01

Tumorigenicity of murine hepatoma cells (MH22a) and their sensitivity to lysis by natural killers (NKs) have been studied after exposure to polychromatic visible and infrared light (VIS-IR, 480-3400 nm, 40 mW/cm2), similar to the terrestrial solar spectrum without its minor UV component, in order to elucidate the involvement of this important environmental and physiotherapeutic factor in regulation of the anti-tumor defense system. The MH22 cells were in vitro exposed to VIS-IR light and their sensitivity to lytic activity of NKs was evaluated. We found that sensitivity of MH22a cells to lysis by NKs after exposure to VIS-IR light at a dose of 4.8 J/cm2 increased 1.5-2 times, while it did not change after exposure to a dose of 9.6 J/cm2 at all ratios (1 : 5-1 : 50) of the number of NKs (effectors) to that of hepatoma cells (targets). The increase in the sensitivity of hepatoma cells to NKs was accompanied by structural changes of cell surface: the capability of supramembraneous glycoproteins (glycocalix) to sorb the vital dye alcian blue (AB) was significantly lower as compared with the unexposed cells of control group. However, no changes in AB sorption was revealed in hepatoma cells exposed to the light at a dose 9.6 J/cm2. Tumorigenicity of photo-irradiated MH22a cells has been studied in the in vivo experiments. Light-exposed (4.8 and 9.6 J/cm2) and intact hepatoma cells were transplanted into syngenic mice C3HA. Tumor volumes 25 days after transplantation proved to be smaller after exposure to the light at both doses than in the control group (4-4.5 times and 2.5-4 times, respectively), which correlated with the increase in the sensitivity to lisys by NKs and decrease in the AB sorption only after light exposure at dose 4.8 J/cm2. Using the flow cytometry method we could show that VIS-IR light at the applied doses did not interfere with the distribution of hepatoma cells over the cycle phases and thus deceleration of the tumor growth was not associated with cytostatic effect of VIS-IR light. To evaluate effect of polychromatic light on the growth of the preformed tumors, the 5-day course of daily light exposures of tumor bearing mice C3HA was carried out in 10 days after subcutaneous transplantation of 2 x 10(5) cells of syngene hepatoma when the tumors had developed in 100% animals. Like in the case of transplantation of the light-exposed cells, irradiation of the tumor bearing mice at doses 4.8-9.6 J/cm2 resulted in deceleration of tumor growth (2.1-2.9 and 2.2 times respectively) for 4 weeks as compared with non-irradiated mice.

The contribution of benzene to smoking-induced leukemia.

PubMed

Korte, J E; Hertz-Picciotto, I; Schulz, M R; Ball, L M; Duell, E J

2000-04-01

Cigarette smoking is associated with an increased risk of leukemia; benzene, an established leukemogen, is present in cigarette smoke. By combining epidemiologic data on the health effects of smoking with risk assessment techniques for low-dose extrapolation, we assessed the proportion of smoking-induced total leukemia and acute myeloid leukemia (AML) attributable to the benzene in cigarette smoke. We fit both linear and quadratic models to data from two benzene-exposed occupational cohorts to estimate the leukemogenic potency of benzene. Using multiple-decrement life tables, we calculated lifetime risks of total leukemia and AML deaths for never, light, and heavy smokers. We repeated these calculations, removing the effect of benzene in cigarettes based on the estimated potencies. From these life tables we determined smoking-attributable risks and benzene-attributable risks. The ratio of the latter to the former constitutes the proportion of smoking-induced cases attributable to benzene. Based on linear potency models, the benzene in cigarette smoke contributed from 8 to 48% of smoking-induced total leukemia deaths [95% upper confidence limit (UCL), 20-66%], and from 12 to 58% of smoking-induced AML deaths (95% UCL, 19-121%). The inclusion of a quadratic term yielded results that were comparable; however, potency models with only quadratic terms resulted in much lower attributable fractions--all < 1%. Thus, benzene is estimated to be responsible for approximately one-tenth to one-half of smoking-induced total leukemia mortality and up to three-fifths of smoking-related AML mortality. In contrast to theoretical arguments that linear models substantially overestimate low-dose risk, linear extrapolations from empirical data over a dose range of 10- to 100-fold resulted in plausible predictions.

Levels of daily light doses under changed day-night cycles regulate temporal segregation of photosynthesis and N2 Fixation in the cyanobacterium Trichodesmium erythraeum IMS101.

PubMed

Cai, Xiaoni; Gao, Kunshan

2015-01-01

While the diazotrophic cyanobacterium Trichodesmium is known to display inverse diurnal performances of photosynthesis and N2 fixation, such a phenomenon has not been well documented under different day-night (L-D) cycles and different levels of light dose exposed to the cells. Here, we show differences in growth, N2 fixation and photosynthetic carbon fixation as well as photochemical performances of Trichodesmium IMS101 grown under 12L:12D, 8L:16D and 16L:8D L-D cycles at 70 μmol photons m-2 s-1 PAR (LL) and 350 μmol photons m-2 s-1 PAR (HL). The specific growth rate was the highest under LL and the lowest under HL under 16L:8D, and it increased under LL and decreased under HL with increased levels of daytime light doses exposed under the different light regimes, respectively. N2 fixation and photosynthetic carbon fixation were affected differentially by changes in the day-night regimes, with the former increasing directly under LL with increased daytime light doses and decreased under HL over growth-saturating light levels. Temporal segregation of N2 fixation from photosynthetic carbon fixation was evidenced under all day-night regimes, showing a time lag between the peak in N2 fixation and dip in carbon fixation. Elongation of light period led to higher N2 fixation rate under LL than under HL, while shortening the light exposure to 8 h delayed the N2 fixation peaking time (at the end of light period) and extended it to night period. Photosynthetic carbon fixation rates and transfer of light photons were always higher under HL than LL, regardless of the day-night cycles. Conclusively, diel performance of N2 fixation possesses functional plasticity, which was regulated by levels of light energy supplies either via changing light levels or length of light exposure.

Photodynamic treatment of epithelial tissue derived from patients with endometrial cancer: a contribution to the role of laminin and epidermal growth factor receptor in photodynamic therapy

NASA Astrophysics Data System (ADS)

Ziolkowski, Piotr P.; Symonowicz, Krzysztof; Osiecka, Beata J.; Rabczynski, Jerzy; Gerber, Jerzy

1999-07-01

Photodynamic therapy (PDT) was used to treat endometrial G1 cancer tissue derived from patients who had undergone a total hysterectomy and bilateral salpingo-oophorectomy. After surgical treatment the cancerous tissue was kept in a medium containing Dulbecco solution, fetal calf serum, and antibiotics. The tissue was then exposed to hematoporphyrin derivative (0.1 mg/l) and 24 h later exposed to light (total light dose--18 J/sq cm). Necrosis depth was evaluated 24 h later using a light microscope. In order to assess the possible role of the basal membrane component laminin, as well as epidermal growth factor receptor susceptibility to PDT, immunohistochemical studies were carried out. Additionally, nucleolar organizer regions evaluation was performed. Our experiment confirmed that PDT results in the necrosis in the treated endometrial cancer, while not affecting the laminin in the cancerous tissue. In contrast, PDT strongly affects the epidermal growth factor receptor and nucleolar organizer regions in cancer cells. We suggest that laminin may contribute to the prevention of cancer dissemination in the cases where PDT has to be repeated, and that after PDT the cells become less susceptible to a mitogen, like, e.g., epidermal growth factor.

Low doses of alcohol substantially decrease glucose metabolism in the human brain.

PubMed

Volkow, Nora D; Wang, Gene-Jack; Franceschi, Dinko; Fowler, Joanna S; Thanos, Panayotis Peter K; Maynard, Laurence; Gatley, S John; Wong, Christopher; Veech, Richard L; Kunos, George; Kai Li, Ting

2006-01-01

Moderate doses of alcohol decrease glucose metabolism in the human brain, which has been interpreted to reflect alcohol-induced decreases in brain activity. Here, we measure the effects of two relatively low doses of alcohol (0.25 g/kg and 0.5 g/kg, or 5 to 10 mM in total body H2O) on glucose metabolism in the human brain. Twenty healthy control subjects were tested using positron emission tomography (PET) and FDG after placebo and after acute oral administration of either 0.25 g/kg, or 0.5 g/kg of alcohol, administered over 40 min. Both doses of alcohol significantly decreased whole-brain glucose metabolism (10% and 23% respectively). The responses differed between doses; whereas the 0.25 g/kg dose predominantly reduced metabolism in cortical regions, the 0.5 g/kg dose reduced metabolism in cortical as well as subcortical regions (i.e. cerebellum, mesencephalon, basal ganglia and thalamus). These doses of alcohol did not significantly change the scores in cognitive performance, which contrasts with our previous results showing that a 13% reduction in brain metabolism by lorazepam was associated with significant impairment in performance on the same battery of cognitive tests. This seemingly paradoxical finding raises the possibility that the large brain metabolic decrements during alcohol intoxication could reflect a shift in the substrate for energy utilization, particularly in light of new evidence that blood-borne acetate, which is markedly increased during intoxication, is a substrate for energy production by the brain.

Estimate of radiation release from MIT reactor with un-finned LEU core during Maximum Hypothetical Accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Kaichao; Hu, Lin-wen; Newton, Thomas

2017-05-01

The Massachusetts Institute of Technology Reactor (MITR-II) is a research reactor in Cambridge, Massachusetts designed primarily for experiments using neutron beam and in-core irradiation facilities. At 6 MW, it delivers neutron flux and energy spectrum comparable to light water reactor (LWR) power reactors in a compact core using highly enriched uranium (HEU) fuel. In the framework of nonproliferation policy, the international community aims to minimize the use of HEU in civilian facilities. Within this context, research and test reactors have started a program to convert HEU fuel to low enriched uranium (LEU) fuel. A new type of LEU fuel basedmore » on a high density alloy of uranium and molybdenum (U-10Mo) is expected to allow the conversion of U.S. domestic high performance reactors like MITR. The current study focuses on the impacts of MITR Maximum Hypothetical Accident (MHA), which is also the Design Basis Accident (DBA), with LEU fuel. The MHA for the MITR is postulated to be a coolant flow blockage in the fuel element that contains the hottest fuel plate. It is assumed that the entire active portion of five fuel plates melts. The analysis shows that, within a 2-h period and by considering all the possible radiation sources and dose pathways, the overall off-site dose is 302.1 mrem (1 rem ¼ 0.01 Sv) Total Effective Dose Equivalent (TEDE) at 8 m exclusion area boundary (EAB) and a higher dose of 392.8 mrem TEDE is found at 21 m EAB. In all cases the dose remains below the 500 mrem total TEDE limit goal based on NUREG-1537 guidelines.« less

Combined photoultrasonic treatment of infected wounds

NASA Astrophysics Data System (ADS)

Zharov, Vladimir P.; Menyaev, Yulian A.; Kalinin, Konstantin L.; Zmievskoy, Gregory N.; Velsher, Leonid Z.; Podkolzin, Alexander A.; Stakhanov, Mikhail L.; Gorchak, Yury Y.; Sarantsev, V. P.

2001-05-01

A new combined photoultrasonic (CPUS) technology for the treatment of infected wounds is suggested. The CPUS principal operation is based on the topical application of a photosensitizer followed by light irradiation in combination with low frequency ultrasonic (US) treatment of wounds. In CPUS, two methods - photodynamic (PDT) and ultrasonic therapies supplement each other beneficially and in conjunction provide a significant effect of deep suppurative inflammatory wounds treatment. The main advantages of the new technology are the combined application of an antibiotic solution and photodynamic therapy to destroy antibiotic- resistant microorganisms, an effective mixing of a photosensitizer in the wound, the US enhancement of photosensitizer impregnation into the membranes of bacteria, the US clearing of wound surface from necrotic products, an increased effective light dose exposure in the whole volume of the deep wound when the light does not penetrate totally inside the wound, an additional bactericidal effect under the US impact, and the combined effect of CPUS activation of the immune system.

Characterization of optically stimulated luminescent dosimeters, OSLDs, for clinical dosimetric measurements.

PubMed

Jursinic, Paul A

2007-12-01

Optically stimulated luminescent dosimeters, OSLDs, are plastic disks infused with aluminum oxide doped with carbon (Al2O3 : C). These disks are encased in a light-tight plastic holder. Crystals of Al2O3 : C when exposed to ionizing radiation store energy that is released as luminescence (420 nm) when the OSLD is illuminated with stimulation light (540 nm). The intensity of the luminescence depends on the dose absorbed by the OSLD and the intensity of the stimulation light. OSLDs used in this work were InLight/OSL Dot dosimeters, which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). The following are dosimetric properties of the OSLD that were determined: After a single irradiation, repeated readings cause the signal to decrease by 0.05% per reading; the signal could be discharged by greater than 98% by illuminating them for more than 45 s with a 150 W tungsten-halogen light; after irradiation there was a transient signal that decayed with a 0.8 min halftime; after the transient signal decay the signal was stable for days; repeated irradiations and readings of an individual OSLD gave a signal with a coefficient of variation of 0.6%; the dose sensitivity of OSLDs from a batch of detectors has a coefficient of variation of 0.9%, response was linear with absorbed dose over a test range of 1-300 cGy; above 300 cGy a small supra-linear behavior occurs; there was no dose-per-pulse dependence over a 388-fold range; there was no dependence on radiation energy or mode for 6 and 15 MV x rays and 6-20 MeV electrons; for Ir-192 gamma rays OSLD had 6% higher sensitivity; the dose sensitivity was unchanged up to an accumulated dose of 20 Gy and thereafter decreased by 4% per 10 Gy of additional accumulated dose; dose sensitivity was not dependent on the angle of incidence of radiation; the OSLD in its light-tight case has an intrinsic buildup of 0.04 g/cm2; dose sensitivity of the OSLD was not dependent on temperature at the time of irradiation in the range of 10-40 degrees C. The clinical use of OSLDs for in vivo dosimetric measurements is shown to be feasible.

Characterization of optically stimulated luminescent dosimeters, OSLDs, for clinical dosimetric measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jursinic, Paul A.

2007-12-15

Optically stimulated luminescent dosimeters, OSLDs, are plastic disks infused with aluminum oxide doped with carbon (Al{sub 2}O{sub 3}:C). These disks are encased in a light-tight plastic holder. Crystals of Al{sub 2}O{sub 3}:C when exposed to ionizing radiation store energy that is released as luminescence (420 nm) when the OSLD is illuminated with stimulation light (540 nm). The intensity of the luminescence depends on the dose absorbed by the OSLD and the intensity of the stimulation light. OSLDs used in this work were InLight/OSL Dot dosimeters, which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). The following are dosimetricmore » properties of the OSLD that were determined: After a single irradiation, repeated readings cause the signal to decrease by 0.05% per reading; the signal could be discharged by greater than 98% by illuminating them for more than 45 s with a 150 W tungsten-halogen light; after irradiation there was a transient signal that decayed with a 0.8 min halftime; after the transient signal decay the signal was stable for days; repeated irradiations and readings of an individual OSLD gave a signal with a coefficient of variation of 0.6%; the dose sensitivity of OSLDs from a batch of detectors has a coefficient of variation of 0.9%, response was linear with absorbed dose over a test range of 1-300 cGy; above 300 cGy a small supra-linear behavior occurs; there was no dose-per-pulse dependence over a 388-fold range; there was no dependence on radiation energy or mode for 6 and 15 MV x rays and 6-20 MeV electrons; for Ir-192 gamma rays OSLD had 6% higher sensitivity; the dose sensitivity was unchanged up to an accumulated dose of 20 Gy and thereafter decreased by 4% per 10 Gy of additional accumulated dose; dose sensitivity was not dependent on the angle of incidence of radiation; the OSLD in its light-tight case has an intrinsic buildup of 0.04 g/cm{sup 2}; dose sensitivity of the OSLD was not dependent on temperature at the time of irradiation in the range of 10-40 deg. C. The clinical use of OSLDs for in vivo dosimetric measurements is shown to be feasible.« less

Quaternized Zn(II) phthalocyanines for photodynamic strategy against resistant periodontal bacteria.

PubMed

Kussovski, Vesselin; Mantareva, Vanya; Durmuş, Mahmut; Angelov, Ivan

2018-04-25

Photodynamic inactivation (PDI) has been featured as an effective strategy in the treatment of acute drug-resistant infections. The efficiency of PDI was evaluated against three periodontal pathogenic bacteria that were tested as drug-resistant strains. In vitro studies were performed with four water-soluble cationic Zn(II) phthalocyanines (ZnPc1-4) and irradiation of a specific light source (light-emitting diode, 665 nm) with three doses (15, 36 and 60 J/cm2). The well detectable fluorescence of ZnPcs allowed the cellular imaging, which suggested relatively high uptakes of ZnPcs into bacterial species. Complete photoinactivation was achieved with all studied ZnPc1-4 for Enterococcus faecalis (E. faecalis) at a light dose of 15 J/cm2. The photodynamic response was high for Prevotella intermedia (P. intermedia) after the application of 6 μM of ZnPc1 and a light dose of 36 J/cm2 and for 6 μM of ZnPc2 at 60 J/cm2. P. intermedia was inactivated with ZnPc3 (4 log) and ZnPc4 (2 log) with irradiation at an optimal dose of 60 J/cm2. Similar photoinactivation results (2 log) were achieved for Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) treated with 6 μM ZnPc1 and ZnPc2 at a light dose of 60 J/cm2. The study suggested that PDI with quaternized Zn(II) phthalocyanines and specific light irradiation appears to be a very useful antimicrobial strategy for effective inactivation of drug-resistant periodontal pathogens.

[A study on flomoxef against respiratory infections in the aged].

PubMed

Tanimoto, H; Chonabayashi, N; Nakamori, Y; Nakatani, T; Yoshimura, K; Noguchi, M; Nakata, K

1987-10-01

Flomoxef (FMOX, 6315-S) was used in the treatment of 10 patients (male 8, female 2) with respiratory infections, and clinical responses and side effects of FMOX were evaluated. The mean age of the patients was 68.2 years, and the mean body weight was 45.8 kg; this background of the patients indicates that most of them were elderly, and light in body weight. FMOX was administrated by drip infusion in 1 g doses twice daily in all the cases. The mean duration of FMOX therapy was 14 days, and the mean total dose administered was 28 g. Efficacy rate was 80% in the 10 cases. Adverse reactions were not observed and no abnormalities in laboratory tests were detected. In conclusion, FMOX is an effective antibiotic in the treatment of aged patients with respiratory infections.

[Ecological and biological characteristics of Drosophila melanogaster features depending on the dose of electromagnetic radiation of various types].

PubMed

Babkina, V V; Chernova, G V; Allenova, E A; Endebera, O P; Naumkina, E N

2013-01-01

Biological effects of exposure to red light (lambda = 660 +/- 10 nm) on the viability and morphophysiological characteristics of Drosophila melanogaster have been studied. The ability of this physical agent to modify these features is shown. The degree of expression and impact of biological effects depend on the dose, functional and genetic status of the organism. The study of the life expectancy of the exposed to EHF and white light D. melanogaster has revealed that expression of the features depends on the radiation doses, genotype, sex, the nature of the position of wings and lighting conditions. It has been found that the dark mode (24 h-night) is more favorable than the artificial lighting. Individuals with the left wing at the top are more sensitive to the external factors.

Morphometrics of cellular damage in mice testis receiving X-ray and high-energy particle irradiation

NASA Technical Reports Server (NTRS)

Sapp, Walter J.

1987-01-01

Murine tests were exposed to single, low doses of either X-ray, helium, or argon radiation. Animals were sacrificed seventy-two hours later. Testes were fixed for transmission electron microscopy (TEM) and sectioned at either 60 nm for TEM observation or at 2 micron for counting using routine light microscope methods. Counts of the total population of surviving spermatogonia, including all type A cells, intermediate, and type B cells, were taken from tubule cross sections identified as Stage 6 and Stage 1 according to spermatogonial configuration. The surviving fraction of spermatogonia as compared to control, S/S sub o, was calculated for each dose. For both ions and X-rays, there was a rapid decline in survival at dose levels of .10 to .15 Gy in Stage 6 tubules. This was followed by a more gradual decrease in population. At higher doses, 0.30 Gy for argon and 0.80 Gy for helium and X-rays, the cell survival rates declined rapidly. Pre-leptotene spermatocytes in Stage 1 tubules exhibited a different survival curve indicating the extreme radio-sensitivity of type B spermatogonia. Data verify that the seminiferous tubules are composed of a heterogeneous population of cells with different radio-sensitivities and that these differences are manifested even at very low doses.

Marrow toxicity of fractionated vs. single dose total body irradiation is identical in a canine model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Storb, R.; Raff, R.F.; Graham, T.

1993-03-20

The authors explored in dogs the marrow toxicity of single dose total body irradiation delivered from two opposing [sup 60]Co sources at a rate of 10 cGy/min and compared results to those seen with total body irradiation administered in 100 cGy fractions with minimum interfraction intervals of 6 hr. Dogs were not given marrow transplants. They found that 200 cGy single dose total body irradiation was sublethal, with 12 of 13 dogs showing hematopoietic recovery and survival. Seven of 21 dogs given 300 cGy single dose total body irradiation survived compared to 6 of 10 dogs given 300 cGy fractionatedmore » total body irradiation. One of 28 dogs given 400 cGy single dose total body irradiation survived compared to none of six given fractionated radiation. With granulocyte colony stimulating factor (GCSF) administered from day 0-21 after 400 cGy total body irradiation, most dogs survived with hematological recovery. Because of the almost uniform success with GCSF after 400 cGy single dose total body irradiation, a study of GCSF after 400 cGy fractionated total body irradiation was deemed not to be informative and, thus, not carried out. Additional comparisons between single dose and fractionated total body irradiation were carried out with GCSF administered after 500 and 600 cGy of total body irradiation. As with lower doses of total body irradiation, no significant survival differences were seen between the two modes of total body irradiation, and only 3 of 26 dogs studied survived with complete hematological recovery. Overall, therefore, survival among dogs given single dose total body irradiation was not different from that of dogs given fractionated total body irradiation (p = .67). Similarly, the slopes of the postirradiation declines of granulocyte and platelet counts and the rates of their recovery in surviving dogs given equal total doses of single versus fractionated total body irradiation were indistinguishable. 24 refs., 3 figs., 2 tabs.« less

Changes in Corneal Density After Accelerated Corneal Collagen Cross-linking With Different Irradiation Intensities and Energy Exposures: 1-Year Follow-up.

PubMed

Akkaya Turhan, Semra; Toker, Ebru

2017-11-01

To determine and compare the changes in corneal density after 2 different protocols of accelerated corneal collagen cross-linking (A-CXL) in patients with progressive keratoconus. Two groups of eyes received A-CXL treatment; 20 eyes received A-CXL using continuous UVA light exposure at 9 mW/cm for 10 minutes with a total energy dose of 5.4 J/cm, and 24 eyes received A-CXL using continuous UVA light exposure at 30 mW/cm for 4 minutes with a total energy dose of 7.2 J/cm. Corneal density was measured with Scheimpflug tomography at 1, 3, 6, and 12 months of follow-up. Densitometry peaked at 1 month (mean: 16.34 ± 3.80, P = 0.006, 9-mW/cm A-CXL; mean: 20.90 ± 2.81, P < 0.0001, 30-mw/cm A-CXL) in both groups, and it decreased over time in 30-mW/cm A-CXL. However, in 9-mW/cm A-CXL, increased corneal densitometry plateaued until 6 months postoperatively and started to decrease thereafter. Densitometry completely returned to baseline after 12 months in both groups. The mean change in density at 1- and 3-month follow-up was higher in the 30-mW A-CXL group than in the 9-mW A-CXL group (P = 0.003, P = 0.044; respectively). High-energy exposure tends to induce more haze in the early posttreatment period, but it is reversible.

Dose-dependent biodistribution of prenatal exposure to rutile-type titanium dioxide nanoparticles on mouse testis

NASA Astrophysics Data System (ADS)

Kubo-Irie, Miyoko; Uchida, Hiroki; Mastuzawa, Shotaro; Yoshida, Yasuko; Shinkai, Yusuke; Suzuki, Kenichiro; Yokota, Satoshi; Oshio, Shigeru; Takeda, Ken

2014-02-01

Titanium dioxide nanoparticles (nano-TiO2), believed to be inert and safe, are used in many products especially rutile-type in cosmetics. Detection, localization, and count of nanoparticles in tissue sections are of considerable current interest. Here, we evaluate the dose-dependent biodistribution of rutile-type nano-TiO2 exposure during pregnancy on offspring testes. Pregnant mice were subcutaneously injected five times with 0.1 ml of sequentially diluted of nano-TiO2 powder, 35 nm with primary diameter, suspensions (1, 10, 100, or 1,000 μg/ml), and received total doses of 0.5, 5, 50, and 500 μg, respectively. Prior to injection, the size distribution of nano-TiO2 was analyzed by dynamic light scattering measurement. The average diameter was increased in a dose-dependent manner. The most diluted concentration, 1 μg/ml suspension, contained small agglomerates averaging 193.3 ± 5.4 nm in diameter. The offspring testes were examined at 12 weeks postpartum. Individual particle analysis in testicular sections under scanning and transmission electron microscopy enabled us to understand the biodistribution. The correlation between nano-TiO2 doses injected to pregnant mice, and the number of agglomerates in the offspring testes was demonstrated to be dose-dependent by semiquantitative evaluation. However, the agglomerate size was below 200 nm in the testicular sections of all recipient groups, independent from the injected dose during pregnancy.

Light dosimetry and dose verification for pleural PDT

NASA Astrophysics Data System (ADS)

Dimofte, Andreea; Sharikova, Anna V.; Meo, Julia L.; Simone, Charles B.; Friedberg, Joseph S.; Zhu, Timothy C.

2013-03-01

In-vivo light dosimetry for patients undergoing photodynamic therapy (PDT) is critical for predicting PDT outcome. Patients in this study are enrolled in a Phase I clinical trial of HPPH-mediated PDT for the treatment of non-small cell lung cancer with pleural effusion. They are administered 4mg per kg body weight HPPH 48 hours before the surgery and receive light therapy with a fluence of 15-45 J/cm2 at 661 and 665nm. Fluence rate (mW/cm2) and cumulative fluence (J/cm2) are monitored at 7 sites during the light treatment delivery using isotropic detectors. Light fluence (rate) delivered to patients is examined as a function of treatment time, volume and surface area. In a previous study, a correlation between the treatment time and the treatment volume and surface area was established. However, we did not include the direct light and the effect of the shape of the pleural surface on the scattered light. A real-time infrared (IR) navigation system was used to separate the contribution from the direct light. An improved expression that accurately calculates the total fluence at the cavity wall as a function of light source location, cavity geometry and optical properties is determined based on theoretical and phantom studies. The theoretical study includes an expression for light fluence rate in an elliptical geometry instead of the spheroid geometry used previously. The calculated light fluence is compared to the measured fluence in patients of different cavity geometries and optical properties. The result can be used as a clinical guideline for future pleural PDT treatment.

Influence of energy density of different light sources on Knoop hardness of a dual-cured resin cement.

PubMed

Piva, Evandro; Correr-Sobrinho, Lourenço; Sinhoreti, Mario Alexandre Coelho; Consani, Simonides; Demarco, Flávio Fernando; Powers, John Michael

2008-01-01

The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated with different light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs) were tested: tungsten halogen light (HAL), light-emitting diode (LED) and xenon plasma-arc (PAC) lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce). Three energy doses were used by modifying the irradiance (I) of each LCU and the irradiation time (T): 24 Jcm(-2) (I/2x2T), 24 Jcm(-2) (IxT) and 48 Jcm(-2) (Ix2T). Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus). Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10). Knoop hardness number (KHN) means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (alpha=5%). Application of 48 J.cm(-2) energy dose through the ceramic using LED (50.5+/-2.8) and HAL (50.9+/-3.7) produced significantly higher KHN means (p<0.05) than the control (44.7+/-3.8). LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.

Optical dosimetry of radiotherapy beams using Cherenkov radiation: the relationship between light emission and dose.

PubMed

Glaser, Adam K; Zhang, Rongxiao; Gladstone, David J; Pogue, Brian W

2014-07-21

Recent studies have proposed that light emitted by the Cherenkov effect may be used for a number of radiation therapy dosimetry applications. There is a correlation between the captured light and expected dose under certain conditions, yet discrepancies have also been observed and a complete examination of the theoretical differences has not been done. In this study, a fundamental comparison between the Cherenkov emission and absorbed dose was explored for x-ray photons, electrons, and protons using both a theoretical and Monte Carlo-based analysis. Based on the findings of where dose correlates with Cherenkov emission, it was concluded that for x-ray photons the light emission would be optimally suited for narrow beam stereotactic radiation therapy and surgery validation studies, for verification of dynamic intensity-modulated and volumetric modulated arc therapy treatment plans in water tanks, near monoenergetic sources (e.g., Co-60 and brachy therapy sources) and also for entrance and exit surface imaging dosimetry of both narrow and broad beams. For electron use, Cherenkov emission was found to be only suitable for surface dosimetry applications. Finally, for proton dosimetry, there exists a fundamental lack of Cherenkov emission at the Bragg peak, making the technique of little use, although post-irradiation detection of light emission from radioisotopes could prove to be useful.

PHOTODYNAMIC THERAPY (PDT) USING HPPH FOR THE TREATMENT OF PRECANCEROUS LESIONS ASSOCIATED WITH BARRETT’S ESOPHAGUS

PubMed Central

Nava, Hector R; Allamaneni, Shyam S; Dougherty, Thomas J; Cooper, Michele T; Tan, Wei; Wilding, Gregory; Henderson, Barbara W

2011-01-01

Background and Objectives Photodynamic therapy (PDT) with porfimer sodium, FDA approved to treat premalignant lesions in Barrett’s esophagus, causes photosensitivity for 6-8 weeks. HPPH (2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a) shows minimal photosensitization of short duration and promising efficacy in preclinical studies. Here we explore toxicity and optimal drug and light dose with endoscopic HPPH-PDT. We also want to know the efficacy of one time treatment with HPPH-PDT. Study Design/Materials and Methods Two nonrandomized dose escalation studies were performed (18 patients each) with biopsy-proven high grade dysplasia or early intramucosal adenocarcinoma of esophagus. HPPH doses ranged from 3 to 6 mg/m2. At 24 or 48 hours after HPPH administration the lesions received one endoscopic exposure to 150, 175 or 200 J/cm of 665 nm light. Results Most patients experienced mild to moderate chest pain requiring symptomatic treatment only. Six patients experienced Grade 3 & 4 adverse events (16.6%). Three esophageal strictures were treated with dilatation. No clear pattern of dose dependence of toxicities emerged. In the drug dose ranging study (light dose of 150 J/cm at 48 h), 3 and 4 mg/m2 of HPPH emerged as most effective. In the light dose ranging study (3 or 4 mg/m2 HPPH, light at 24 h), complete response rates (disappearance of high grade dysplasia and early carcinoma) of 72% were achieved at 1 year, with all patients treated with 3 mg/m2 HPPH plus 175 J/cm and 4 mg/m2 HPPH plus 150 J/cm showing complete responses at 1 year. Conclusions HPPH-PDT for precancerous lesions in Barrett’s esophagus appears to be safe and showing promising efficacy. Further clinical studies are required to establish the use of HPPH-PDT. PMID:22057498

Explicit macroscopic singlet oxygen modeling for benzoporphyrin derivative monoacid ring A (BPD)-mediated photodynamic therapy.

PubMed

Kim, Michele M; Penjweini, Rozhin; Liang, Xing; Zhu, Timothy C

2016-11-01

Photodynamic therapy (PDT) is an effective non-ionizing treatment modality that is currently being used for various malignant and non-malignant diseases. In type II PDT with photosensitizers such as benzoporphyrin monoacid ring A (BPD), cell death is based on the creation of singlet oxygen ( 1 O 2 ). With a previously proposed empirical five-parameter macroscopic model, the threshold dose of singlet oxygen ([ 1 O 2 ] rx,sh ]) to cause tissue necrosis in tumors treated with PDT was determined along with a range of the magnitude of the relevant photochemical parameters: the photochemical oxygen consumption rate per light fluence rate and photosensitizer concentration (ξ), the probability ratio of 1 O 2 to react with ground state photosensitizer compared to a cellular target (σ), the ratio of the monomolecular decay rate of the triplet state photosensitizer (β), the low photosensitizer concentration correction factor (δ), and the macroscopic maximum oxygen supply rate (g). Mice bearing radiation-induced fibrosarcoma (RIF) tumors were treated interstitially with a linear light source at 690nm with total energy released per unit length of 22.5-135J/cm and source power per unit length of 12-150mW/cm to induce different radii of necrosis. A fitting algorithm was developed to determine the photochemical parameters by minimizing the error function involving the range between the calculated reacted singlet oxygen ([ 1 O 2 ] rx ) at necrosis radius and the [ 1 O 2 ] rx,sh . [ 1 O 2 ] rx was calculated based on explicit dosimetry of the light fluence distribution, the tissue optical properties, and the BPD concentration. The initial ground state oxygen concentration ([ 3 O 2 ] 0 ) was set to be 40μM in this study. The photochemical parameters were found to be ξ=(55±40)×10 -3 cm 2 mW -1 s -1 , σ=(1.8±3)×10 -5 μM -1 , and g=1.7±0.7μMs -1 . We have taken the literature values for δ=33μM, and β=11.9μM. [ 1 O 2 ] rx has shown promise to be a more effective dosimetry quantity for predicting necrosis than either light dose or PDT dose, where the latter is simplistically a temporal integral of the products of the photosensitizer concentration and light fluence rate. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimization of light source parameters in the photodynamic therapy of heterogeneous prostate

NASA Astrophysics Data System (ADS)

Li, Jun; Altschuler, Martin D.; Hahn, Stephen M.; Zhu, Timothy C.

2008-08-01

The three-dimensional (3D) heterogeneous distributions of optical properties in a patient prostate can now be measured in vivo. Such data can be used to obtain a more accurate light-fluence kernel. (For specified sources and points, the kernel gives the fluence delivered to a point by a source of unit strength.) In turn, the kernel can be used to solve the inverse problem that determines the source strengths needed to deliver a prescribed photodynamic therapy (PDT) dose (or light-fluence) distribution within the prostate (assuming uniform drug concentration). We have developed and tested computational procedures to use the new heterogeneous data to optimize delivered light-fluence. New problems arise, however, in quickly obtaining an accurate kernel following the insertion of interstitial light sources and data acquisition. (1) The light-fluence kernel must be calculated in 3D and separately for each light source, which increases kernel size. (2) An accurate kernel for light scattering in a heterogeneous medium requires ray tracing and volume partitioning, thus significant calculation time. To address these problems, two different kernels were examined and compared for speed of creation and accuracy of dose. Kernels derived more quickly involve simpler algorithms. Our goal is to achieve optimal dose planning with patient-specific heterogeneous optical data applied through accurate kernels, all within clinical times. The optimization process is restricted to accepting the given (interstitially inserted) sources, and determining the best source strengths with which to obtain a prescribed dose. The Cimmino feasibility algorithm is used for this purpose. The dose distribution and source weights obtained for each kernel are analyzed. In clinical use, optimization will also be performed prior to source insertion to obtain initial source positions, source lengths and source weights, but with the assumption of homogeneous optical properties. For this reason, we compare the results from heterogeneous optical data with those obtained from average homogeneous optical properties. The optimized treatment plans are also compared with the reference clinical plan, defined as the plan with sources of equal strength, distributed regularly in space, which delivers a mean value of prescribed fluence at detector locations within the treatment region. The study suggests that comprehensive optimization of source parameters (i.e. strengths, lengths and locations) is feasible, thus allowing acceptable dose coverage in a heterogeneous prostate PDT within the time constraints of the PDT procedure.

Evanescent-wave Infrared Optical Fiber Gas Sensor

NASA Astrophysics Data System (ADS)

Wang, Yiding; Wang, Di; Zhong, Hong-Jie; Zhang, Zhiguo

2000-03-01

We propose the treatment of amblyopia using yellow-green laser diodes.There are amblyopia children in excess of fifty million in the world.Because the causative agent of amblyopia hasn't been well understood,only roughly considered to be concerned with visual sense cell,optic nerve network and function of nerve center,no appropriate treatment is found up to date.The vision of person is determined by the center hollow region of retina,where there are three kinds of cone cell.The corresponding peak wavelength in absorption spectrum locates 447nm(blue light),532nm (green light)and 565nm(yellow light), respectively.When stimulated by white light, excited degree of three kinds of cone cell are identical,or yellow-green light,to which person eye is most sensitive, will significantly takes effects.Therefore the yellow-green laser diode is suitable for treating amblyopia. The weak laser,namely laser power less than mW order of magnitude,shows curative by stimulating bion tissue.When stimulating light power density is less than 0.001W/cm,the compounding speed of nucleic acid DNA is significantly increased.The growth rate of cell,activity of enzyme,content of hemoglobin and the growth of blood vessel,are all increased.However,it's key to control the dose of light.When the dose transcend some value,a inhibition will occur.The little dose of weak laser treatment can be accumulated with a parabolic characteristics,that is the weak laser generate bion response stengthening gradually versus time.Then it will weaken gradually after the peak.When the treatment duration is longer than a certain time,a inhibition also takes place.A suggested theraphy is characterized by little dose and short treatment course. In a conclusion, the yellow-green laser diode should be used for the treatment of amblyopia.The little dose and short treatment couse are to be adopted.

A Treatment of Amblyopia Using Laser Diodes

NASA Astrophysics Data System (ADS)

Wang, Di; Wang, Yi-Ding; Liu, Bing-Chun

2000-04-01

We propose the treatment of amblyopia using yellow-green laser diodes. There are amblyopia children in excess of fifty million in the world. Because the causative agent of amblyopia hasn't been well understood,only roughly considered to be concerned with visual sense cell, optic nerve network and function of nerve center, no appropriate treatment is found up to date. The vision of person is determined by the center hollow region of retina, where there are three kinds of cone cell. The corresponding peak wavelength in absorption spectrum locates 447nm (blue light), 532nm (green light) and 565nm (yellow light), respectively. When stimulated by white light, excited degree of three kinds of cone cell are identical,or yellow-green light, to which person eye is most sensitive, will significantly takes effects. Therefore the yellow-green laser diode is suitable for treating amblyopia. The weak laser, namely laser power less than mW order of magnitude, shows curative by stimulating bion tissue. When stimulating light power density is less than 0.001W/cm, the compounding speed of nucleic acid DNA is significantly increased. The growth rate of cell, activity of enzyme, content of hemoglobin and the growth of blood vessel, are all increased. However, it's key to control the dose of light. When the dose transcend some value, a inhibition will occur. The little dose of weak laser treatment can be accumulated with a parabolic characteristics, that is the weak laser generate bion response stengthening gradually versus time. Then it will weaken gradually after the peak. When the treatment duration is longer than a certain time, a inhibition also takes place. A suggested theraphy is characterized by little dose and short treatment course. In a conclusion, the yellow-green laser diode should be used for the treatment of amblyopia. The little dose and short treatment couse are to be adopted. Key words:treatment amblyopia laser diode

Ultraviolet-B radiation increases serum 25-hydroxyvitamin D levels: the effect of UVB dose and skin color.

PubMed

Armas, Laura A G; Dowell, Susan; Akhter, Mohammed; Duthuluru, Sowjanya; Huerter, Christopher; Hollis, Bruce W; Lund, Richard; Heaney, Robert P

2007-10-01

Ultraviolet (UV)-B light increases vitamin D levels, but the dose response and the effect of skin pigmentation have not been well characterized. We sought to define the relationship between UVB exposure and 25-hydroxyvitamin D (25-OH-D) concentrations as a function of skin pigmentation. Seventy two participants with various skin tones had 90% of their skin exposed to UVB light (20-80 mJ/cm2) 3 times a week for 4 weeks. Serum 25-OH-D was measured weekly. Eighty percent of the variation in treatment response was explained by UVB dose and skin tone. Therapeutically important changes in 25-OH-D were achieved with minimal tanning. Four weeks was not long enough to reach a steady state at the higher dose rates. The response of 25-OH-D levels to UVB light is dependent on skin pigmentation and the amount of UVB given, and useful increases in vitamin D status can be achieved by defined UVB doses small enough to produce only minimal tanning.

Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

1982-10-01

Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with /sup 60/Co gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of /sup 60/Co radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose permore » rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. We found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents.« less

Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, L.H.; McCormick, J.B.; Johnson, K.M.

1982-10-01

Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with /sup 60/CO gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of /sup 60/CO radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose permore » rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. The authors found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents.« less

Methyl mercury toxicity in plant cultures: modification of resistance and demethylation by light and/or 2,4-dichlorophenoxyacetic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Czuba, M.

1987-04-01

Cultures of Daucus carota, Ca-68-10, and Lactuca sativa, Le-67, were grown at increasing methyl mercury (MeHg) concentrations ranging from initial doses of 0.05 to 5.0 micrograms/ml per day for 4 days with or without 0.15 microgram/ml 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence or absence of light. The presence of 2,4-D interacted with light synergistically in the expression of MeHg toxicity within the whole range of concentrations. Demethylation patterns increased or decreased depending on the species, the 2,4-D concentration in the medium, and methyl mercury concentration used in the treatment. Lettuce was more sensitive to this interaction than carrot. In lettuce,more » the presence of 2,4-D in the light lowered the concentration of total Hg (or MeHg) required to reduce growth by 50%, about 13 times relative to that in the dark (i.e., it sensitized the cells). In the absence of 2,4-D the pattern was reversed. In carrot the pattern was similar but less pronounced. This suggests that, in these cell populations, MeHg toxicity is partly a hormone-mediated and light-sensitive event.« less

Acute alerting effects of light: A systematic literature review.

PubMed

Souman, Jan L; Tinga, Angelica M; Te Pas, Susan F; van Ee, Raymond; Vlaskamp, Björn N S

2018-01-30

Periodic, well timed exposure to light is important for our health and wellbeing. Light, in particular in the blue part of the spectrum, is thought to affect alertness both indirectly, by modifying circadian rhythms, and directly, giving rise to acute effects. We performed a systematic review of empirical studies on direct, acute effects of light on alertness to evaluate the reliability of these effects. In total, we identified 68 studies in which either light intensity, spectral distribution, or both were manipulated, and evaluated the effects on behavioral measures of alertness, either subjectively or measured in reaction time performance tasks. The results show that increasing the intensity of polychromatic white light has been found to increase subjective ratings of alertness in a majority of studies, though a substantial proportion of studies failed to find significant effects, possibly due to small sample sizes or high baseline light intensities. The effect of the color temperature of white light on subjective alertness is less clear. Some studies found increased alertness with higher color temperatures, but other studies reported no detrimental effects of filtering out the short wavelengths from the spectrum. Similarly, studies that used monochromatic light exposure showed no systematic pattern for the effects of blue light compared to longer wavelengths. Far fewer studies investigated the effects of light intensity or spectrum on alertness as measured with reaction time tasks and of those, very few reported significant effects. In general, the small sample sizes used in studies on acute alerting effects of light make it difficult to draw definitive conclusions and better powered studies are needed, especially studies that allow for the construction of dose-response curves. Copyright © 2017 Elsevier B.V. All rights reserved.

Interstitial photodynamic therapy in combination with Cetuximab for recurrent head and neck squamous cell carcinoma

NASA Astrophysics Data System (ADS)

Rigual, Nestor; Dildeep, Ambujakshan; Shafirstein, Gal

2013-03-01

Background and Purpose: Combination therapy of interstitial photodynamic therapy (iPDT) with Cetuximab to attain symptomatic control of recurrent head and neck cancer. Methods: Two patients with Unresectable recurrent Head and Neck SCC were treated with iPDT alone and iPDT and cetuximab. Treatments were administered in an outpatient setting. A single dose of Photofrin at 2 mg per kilogram of body weight was administered intravenously two days prior to laser illumination. The iPDT was accomplished by delivering 630-nm laser light through two laser fibers with 2.5 and 5 cm long diffusive ends. Light irradiance of 400 mW/cm for 250 seconds was used to deliver a total of 100 J/cm, during the iPDT. Light applications were conducted, twice, at 3-4 days interval. One of the patients was treated with cetuximab along with iPDT. Results: Near total resolution of tumor was observed in the patient treated with iPDT and cetuximab, and partial resolution was seen in the patient treated with iPDT alone. Conclusion: Interstitial photodynamic therapy may be used to treat patients with recurrent unresectable head and neck cancer. The combination of iPDT with Cetuximab has the potential to improve tumor response in the patient population for whom there is no effective therapies. This observation merits further studies.

The evaluation and planning of light dose in photodynamic therapy for port wine stains

NASA Astrophysics Data System (ADS)

Zhang, Feng-juan; Hu, Xiaoming; Zhang, Qi-shen

2014-11-01

Photodynamic therapy (PDT) is one of the best available treatment for dermatology, especially for port wine stains (PWS), in which the efficacy is associated with the light dose, the photosensitizer concentration, the oxygen concentration and so on. Accurate control of the light dose will help doctors develop more effective treatment protocols, and reduce the treatment cost. Considering the characters of PWS, a binocular vision system composed of a camera, a digital projector and a computing unit is designed. An accurate 3D modeling of patients was achieved using a gray coding structured light, and then the lesions were segmented based on HSV space. Subsequently, each 3D point is fit on the surface by a nearest neighbor algorithm and the surface normal can be obtained. Three dimensional localization of lesion provide digital objective basis for automatic control of light device. The irradiance on the surface at a given angle can be assessed, and the optimum angle for the treatment can be solved and optimized by the doctor to improve irradiation areas.

Neuroprotective Dose Response in RCS Rats Implanted with Microphotodiode Arrays

PubMed Central

Pardue, Machelle T.; Kim, Moon K.; Walker, Tiffany A.; Faulkner, Amanda E.; Chow, Alan Y.; Ciavatta, Vincent T.

2012-01-01

Purpose Neuropreservation of retinal function and structure in RCS rats following implantation of a microphotodiode array (MPA) has been shown in previous studies(Pardue et al. 2005a; Pardue et al. 2005b). Since microphotodiodes produce electrical currents in proportion to the intensity of incident light, increased light exposure may result in greater neuroprotective effects. Our previous studies suggested that the frequency of light exposure to electroretinogram (ERG) flash stimuli might provide increased neuroprotection. Thus, in this study, we examined the dose response of subretinal electrical stimulation by exposing RCS rats implanted with MPAs to variable durations and combinations of two different lighting regimens: pulsing incandescent bulbs and xenon stimuli from an ERG Ganzfeld. While incandescent light regimens did not produce any significant differences in ERG function, we found significantly greater dark-adapted ERG b-wave amplitudes in RCS rats that received weekly versus biweekly ERGs over the course of 8 weeks of follow-up. These results suggest that subretinal electrical stimulation may be optimized to produce greater neuroprotective effects by dosing with periodic higher current. PMID:22183323

Laser-based irradiation apparatus and method to measure the functional dose-rate response of semiconductor devices

DOEpatents

Horn, Kevin M [Albuquerque, NM

2008-05-20

A broad-beam laser irradiation apparatus can measure the parametric or functional response of a semiconductor device to exposure to dose-rate equivalent infrared laser light. Comparisons of dose-rate response from before, during, and after accelerated aging of a device, or from periodic sampling of devices from fielded operational systems can determine if aging has affected the device's overall functionality. The dependence of these changes on equivalent dose-rate pulse intensity and/or duration can be measured with the apparatus. The synchronized introduction of external electrical transients into the device under test can be used to simulate the electrical effects of the surrounding circuitry's response to a radiation exposure while exposing the device to dose-rate equivalent infrared laser light.

Photodynamic therapy and fluorescent diagnostics of breast cancer

NASA Astrophysics Data System (ADS)

Vakulovskaya, Elena G.; Letyagin, Victor P.; Umnova, Loubov V.; Vorozhcsov, Georgiu N.; Philinov, Victor

2004-06-01

Photodynamic Therapy (PDT) and fluorescent diagnostics (FD) using Photosense have been provided in 26 patients with breast cancer (BC) and in 108 patients with skin metastases of BC. In 22 patients with T1-T2N0M0 primary tumor PDT was preoperative treatment, with radical mastectomy 7-10 days after PDT. 4 patients had residual tumor after radiotherapy. FD was fulfilled with spectranalyser. We used semiconductive laser for PDT-λ=672+2nm, P=1,5 W, interstitial irradiation 2-24 hours after PS injection in light dose 150-200 J/cm3 in patients with primary tumor and multiple surface irradiations (1-4) with interval 24-48 hours and total light dose 400-600 J/cm2 for metastases. Partial regression of tumor with pathomorphosis of 2-4 degree has been found in 23 cases in first group. Treating metastases we had overall response rate of 86,9% with complete response (CR) in 51,5% and partial response in 35,4%. In a year after PDT in 52 patients with CR we had CR in 36,6%, local recurrences in 23,1%, progression (distant [lung or bone] metastasis) in 40,4% of cases. Our experience show pronounced efficacy of FD for detecting tumor borders and PDT for treating BC as preoperative modality and as palliation in cases of recurrencies.

PDT dose dosimetry for Photofrin-mediated pleural photodynamic therapy (pPDT)

NASA Astrophysics Data System (ADS)

Ong, Yi Hong; Kim, Michele M.; Finlay, Jarod C.; Dimofte, Andreea; Singhal, Sunil; Glatstein, Eli; Cengel, Keith A.; Zhu, Timothy C.

2018-01-01

Photosensitizer fluorescence excited by photodynamic therapy (PDT) treatment light can be used to monitor the in vivo concentration of the photosensitizer and its photobleaching. The temporal integral of the product of in vivo photosensitizer concentration and light fluence is called PDT dose, which is an important dosimetry quantity for PDT. However, the detected photosensitizer fluorescence may be distorted by variations in the absorption and scattering of both excitation and fluorescence light in tissue. Therefore, correction of the measured fluorescence for distortion due to variable optical properties is required for absolute quantification of photosensitizer concentration. In this study, we have developed a four-channel PDT dose dosimetry system to simultaneously acquire light dosimetry and photosensitizer fluorescence data. We measured PDT dose at four sites in the pleural cavity during pleural PDT. We have determined an empirical optical property correction function using Monte Carlo simulations of fluorescence for a range of physiologically relevant tissue optical properties. Parameters of the optical property correction function for Photofrin fluorescence were determined experimentally using tissue-simulating phantoms. In vivo measurements of photosensitizer fluorescence showed negligible photobleaching of Photofrin during the PDT treatment, but large intra- and inter-patient heterogeneities of in vivo Photofrin concentration are observed. PDT doses delivered to 22 sites in the pleural cavity of 8 patients were different by 2.9 times intra-patient and 8.3 times inter-patient.

Development of radiochromic film for spatially quantitative dosimetric analysis of indirect ionizing radiation fields

NASA Astrophysics Data System (ADS)

Brady, Samuel Loren

Two types of radiochromic films (RCF) were characterized for this work: EBT and XRQA film. Both films were investigated for: radiation interaction with film structure; light interaction with film structure for optimal film readout (densitometry) sensitivity; range of absorbed dose measurements; dependence of film dose measurement response as a function of changing radiation energy; fractionation and dose rate effects on film measurement response; film response sensitivity to ambient factors; and stability of measured film response with time. EBT film was shown to have the following properties: near water equivalent atomic weight (Zeff); dynamic dose range of 10 -1-102 Gy; 3% change in optical density (OD) response for a single exposure level when exposed to radiation energies from (75-18,000) kV; and best digitized using transmission densitometry. XRQA film was shown to have: a Zeff of ˜25; a 12 fold increase in sensitivity at lower photon energies for a dynamic dose range of 10-3-100 Gy, a difference of 25% in OD response when comparing 120 kV to 320 kV, and best digitized using reflective densitometry. Both XRQA and EBT films were shown to have: a temporal stability (DeltaOD) of ˜1% for t > 24 hr post film exposure for up to ˜20 days; a change in dose response of ˜0.03 mGy hr-1 when exposed to fluorescent room lighting at standard room temperature and humidity levels; a negligible dose rate and fractionation effect when operated within the optimal dose ranges; and a light wavelength dependence with dose for film readout. The flat bed scanner was chosen as the primary film digitizer due to its availability, cost, OD range, functionality (transmission and reflection scanning), and digitization speed. As a cost verses functionality comparison, the intrinsic and operational limitations were determined for two flat bed scanners. The EPSON V700 and 10000XL exhibited equal spatial and OD accuracy. The combined precision of both the scanner light sources and CCD sensors measured < 2% and < 7% deviation in pixel light intensities for 50 consecutive scans, respectively. Both scanner light sources were shown to be uniform in transmission and reflection scan modes along the center axis of light source translation. Additionally, RCFs demonstrated a larger dynamic range in pixel light intensities, and to be less sensitive to off axis light inhomogeneity, when scanned in landscape mode (long axis of film parallel with axis of light source translation). The EPSON 10000XL demonstrated slightly better light source/CCD temporal stability and provided a capacity to scan larger film formats at the center of the scanner in landscape mode. However, the EPSON V700 only measured an overall difference in accuracy and precision by 2%, and though smaller in size, at the time of this work, was one sixth the cost of the 10000XL. A scan protocol was developed to maximize RCF digitization accuracy and precision, and a calibration fitting function was developed for RCF absolute dosimetry. The fitting function demonstrated a superior goodness of fit for both RCF types over a large range of absorbed dose levels as compared to the currently accepted function found in literature. The RCF dosimetry system was applied to three novel areas from which a benefit could be derived for 2D or 3D dosimetric information. The first area was for a 3D dosimetry of a pendant breast in 3D-CT mammography. The novel method of developing a volumetric image of the breast from a CT acquisition technique was empirically measured for its dosimetry and compared to standard dual field digital mammography. The second area was dose reduction in CT for pediatric and adult scan protocols. In this application, novel methodologies were developed to measure 3D organ dosimetry and characterize a dose reduction scan protocol for pediatric and adult body habitus. The third area was in the field of small animal irradiation for radiobiology purposes and cancer patient treatment verification. In every case, the RCF dosimetry system was verified for accuracy using a traditional PDD as the golden standard. When considering all areas of radiation energy applications, the RCF dosimetry system agreed to better than 7% of the golden standard, and in some cases within better than 1%. In many instances, this work provided vital dosimetric information that otherwise was not captured using the PDD in similar geometry. This work demonstrates the need for RCF to more accurately measure volumetric dose. (Abstract shortened by UMI.)

Once the Light Touch to the Brain: Cytotoxic Effects of Low-Dose Gamma-Ray, Laser Light, and Visible Light on Rat Neuronal Cell Culture

PubMed Central

Cakir, Murteza; Colak, Abdullah; Calikoglu, Cagatay; Taspinar, Numan; Sagsoz, Mustafa Erdem; Kadioglu, Hakan Hadi; Hacimuftuoglu, Ahmet; Seven, Sabriye

2016-01-01

Objective: We aimed to evaluate the effects of gamma-ray, laser light, and visible light, which neurons are commonly exposed to during treatment of various cranial diseases, on the viability of neurons. Materials and Methods: Neuronal cell culture was prepared from the frontal cortex of 9 newborn rats. Cultured cells were irradiated with gamma-ray for 1–10 min by 152Eu, 241Am, and 132Ba isotopes, visible light for 1–160 min, and laser light for 0.2–2 seconds. The MTT tetrazolium reduction assay was used to assess the number of viable cells in the neuronal cell cultures. Wavelength dispersive X-ray fluorescence spectrometer was used to determine Na, K, and Ca levels in cellular fluid obtained from neuronal cell culture plaques. Results: Under low-dose radiation with 152Eu, 241Am, and 132Ba isotopes, cell viability insignificantly decreased with time (p>0.05). On the other hand, exposure to visible light produced statistically significant decrease in cell viability at both short- (1–10 min) and long-term (20–160 min). Cell viability did not change with 2 seconds of laser exposure. Na, K, and Ca levels significantly decreased with gamma-ray and visible light. The level of oxidative stress markers significantly changed with gamma-ray. Conclusion: In conclusion, while low dose gamma-ray has slight to moderate apoptotic effect in neuronal cell cultures by oxidative stress, long-term visible light induces remarkable apoptosis and cell death. Laser light has no significant effect on neurons. Further genetic studies are needed to clarify the chronic effect of visible light on neuronal development and functions. PMID:27551168

Investigation of the effect of traditional Chinese medicine on pain and inflammation in chronic nonbacterial prostatitis in rats.

PubMed

Liu, Y-J; Song, G-H; Liu, G T

2016-08-01

According to traditional Chinese medicine, the symptoms of chronic nonbacterial prostatitis/chronic pelvic pain syndrome (CNP/CPPS) may be treated using a cocktail of herbs that stimulate blood circulation ('activating blood circulation formula'). We investigated the effect of three doses of this formula on a rat model of CNP/CPPS. Male Wistar rats were injected with a saline extract of male sex accessory glands on days 0 and 30 to induce prostatitis and then treated daily by gavage between days 32 and 60. Treatment with low, medium and high doses of activating blood circulation formula resulted in an almost total rescue of paw withdrawal threshold at day 60, and treatment with the highest dose also significantly decreased prostate inflammation (assessed histopathologically). We further observed elevated serum prostaglandin E2 levels in the CNP/CPPS model which decreased upon high-dose treatment, and increased Cox-2 expression in the prostate and spinal cord dorsal horn which was rescued in both tissues in the high-dose group and in the prostate in the medium-dose group. These results shed light on a possible mechanism by which activating blood circulation therapy may alleviate pain in a rat model of CNP/CPPS by downregulating Cox-2 expression in the spinal cord, thereby raising the pain threshold. Further research will be needed to fully characterise the mechanism by which activating blood circulation therapy produces this therapeutic effect. © 2016 Blackwell Verlag GmbH.

Modulating intracellular acidification by regulating the incubation time of proton caged compounds.

PubMed

Carbone, Marilena; Sabbatella, Gianfranco; Antonaroli, Simonetta; Orlando, Viviana; Biagioni, Stefano; Nucara, Alessandro

2016-09-01

A proton caged compound, the 1-(2-nitrophenyl)- ethylhexadecyl sulfonate (HDNS), was dosed into HEK-293 at different incubation times. Samples were irradiated with filtered UV light for inducing photolysis of the HDNS and then probed by infrared spectroscopy. The intracellular acidification reaction can be followed by monitoring the consequent CO2 peak intensity variation. The total CO2 produced is similar for all the samples, hence it is only a function of the initial HDNS concentration. The way it is achieved, though, is different for the different incubation times and follows kinetics, which results in a combination of a linear CO2 increase and a steep CO2 increase followed by a decay. This is interpreted in terms of confinement of the HDNS into intracellular vesicles of variable average size and sensitive to UV light when they reach critical dimensions.

Novel Measure of Opioid Dose and Costs of Care for Diabetes Mellitus: Opioid Dose and Health Care Costs.

PubMed

Gautam, Santosh; Franzini, Luisa; Mikhail, Osama I; Chan, Wenyaw; Turner, Barbara J

2016-03-01

Diabetes mellitus (DM) has well known costly complications but we hypothesized that costs of care for chronic pain treated with opioid analgesic (OA) medications would also be substantial. In a statewide, privately insured cohort of 29,033 adults aged 18 to 64 years with DM and noncancer pain who filled OA prescription(s) from 2008 to 2012, our outcomes were costs for specific health care services and total costs per 6-month intervals after the first filled OA prescription. Average daily OA dose (4 categories) and total dose (quartiles) in morphine-equivalent milligrams were calculated per 6-month interval after the first OA prescription and combined into a novel OA dose measure. Associations of OA measures with costs of care (n = 126,854 6-month intervals) were examined using generalized estimating equations adjusted for clinical conditions, psychotherapeutic drugs, and DM treatment. Incremental costs for each type of health care service and total cost of care increased progressively with average daily and total OA dose versus no OAs. The combined OA measure identified the highest incremental total costs per 6-month interval that were increased by $8,389 for 50- to 99-mg average daily dose plus >900 mg total dose and, by $9,181 and $9,958 respectively, for ≥100 mg average daily dose plus 301- to 900-mg or >900 mg total dose. In this statewide DM cohort, total health care costs per 6-month interval increased progressively with higher average daily OA dose and with total OA dose but the greatest increases of >$8,000 were distinguished by combinations of higher average daily and total OA doses. The higher costs of care for opioid-treated patients appeared for all types of services and likely reflects multiple factors including morbidity from the underlying cause of pain, care and complications related to opioid use, and poorer control of diabetes as found in other studies. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Benzoporphyrin derivative and light-emitting diode for use in photodynamic therapy: Applications of space light-emitting diode technology

NASA Astrophysics Data System (ADS)

Whelan, Harry T.; Houle, John M.; Bajic, Dawn M.; Schmidt, Meic H.; Reichert, Kenneth W.; Meyer, Glenn A.

1998-01-01

Photodynamic therapy (PDT) is a cancer treatment modality that recently has been applied as adjuvant therapy for brain tumors. PDT consists of intravenously injecting a photosensitizer, which preferentially accumulates in tumor cells, into a patient and then activating the photosensitizer with a light source. This results in free radical generation followed by cell death. The development of more effective light sources for PDT of brain tumors has been facilitated by applications of space light-emitting diode array technology; thus permitting deeper tumor penetration of light and use of better photosensitizers. Currently, the most commonly used photosensitizer for brain tumor PDT is Photofrin®. Photofrin® is a heterogeneous mixture of compounds derived from hematoporphyrin. Photofrin® is activated with a 630 nm laser light and does destroy tumor cells in animal models and humans. However, treatment failure does occur using this method. Most investigators attribute this failure to the limited penetration of brain tissue by a 630 nm laser light and to the fact that Photofrin® has only a minor absorption peak at 630 nm, meaning that only a small fraction of the chemical is activated. Benzoporphyrin Derivative Monoacid Ring A (BPD) is a new, second generation photosensitizer that can potentially improve PDT for brain tumors. BPD has a major absorption peak at 690 nm, which gives it two distinct advantages over Photofrin®. First, longer wavelengths of light penetrate brain tissue more easily so that larger tumors could be treated, and second, the major absorption peak means that a larger fraction of the drug is activated upon exposure to light. In the first part of this project we have studied the tumoricidal effects of BPD in vitro using 2A9 canine glioma and U373 human glioblastoma cell cultures. Using light emitting diodes (LED) with a peak emission of 688 nm as a light source, cell kill of up to 86 percent was measured in these cell lines by tumor DNA synthesis reduction. The effectiveness of BPD against tumor cells in vitro thus established, we have taken the first step toward determining its effectiveness in vivo. The second part of this project consisted of experiments performed to determine the maximum tolerated dose (MTD) of both BPD and LED light. At a light dose of 100 J/cm2, skin damage and neurotoxicity were seen at a BPD dose of 1.0 mg/kg, but not at a dose of 0.75 mg/kg. When BPD remained constant at 0.75 mg/kg, skin damage was seen at light dosages of 125 J/cm2, 150 J/cm2 and 175 J/cm2. One dog also died at a light dose of 175 J/cm2. Further studies will be needed to determine the effectiveness of BPD against tumor cells in vivo.

Tretinoin Photostability

PubMed Central

Rosso, James Del; Harper, Julie; Pillai, Radhakrishnan; Moore, Robert

2013-01-01

Background: Various formulations of tretinoin have been reported to be unstable after exposure to artificial light or sunlight. The observation that tretinoin is photolabile in the presence of light led to the recommendation that tretinoin be applied in the evening in order to avoid photodegradation, which could potentially reduce efficacy. More recently, the development of innovative vehicle formulations has led, in some cases, to a marked decrease in the photodegradation of tretinoin. Objective: To compare the photostability of a micronized aqueous-based formulation of tretinoin gel 0.05% with tretinoin gel 0.025% following exposure to fluorescent and simulated solar light conditions in vitro. Methods: Micronized tretinoin gel 0.05% and tretinoin gel 0.025% were exposed to fluorescent light over eight hours or simulated solar light up to 600mJ/cm2 (equivalent to 30 minimal erythemal dose). Product samples were prepared and analyzed for tretinoin concentration using high-performance liquid chromatography. Additional duplicate samples were similarly prepared and analyzed after 2, 4, 6, and 8 hours. Results: There was an 11-percent degradation of tretinoin 0.05% formulated as the micronized gel compared to an 86-percent degradation of tretinoin 0.025% formulated as the conventional gel following eight hours of exposure to fluorescent light in vitro. The degradation of tretinoin 0.025% in the conventional gel was greater than 83 percent within two hours. In the second light exposure study, in vitro exposure to simulated solar light provided a gradual dose-response effect with tretinoin 0.05% formulated as the micronized tretinoin gel. The photodegradation of tretinoin 0.025% in the conventional gel was more immediate and of substantial magnitude (>85%) after exposures at all minimal erythemal dose levels. Conclusion: Tretinoin 0.05% formulated as a micronized gel 0.05% showed minimal degradation when exposed to fluorescent light over eight hours. This same formulation exhibited a clear dose-response degradation pattern when exposed to simulated solar light. In contrast, tretinoin 0.025% formulated in a conventional gel exhibited marked photodegradation within the first two hours when exposed to both light conditions in vitro. This information adds to the body of evidence that supports the observation that certain vehicle formulations may reduce the potential for photodegradation of tretinoin. PMID:23441237

Ozone-induced foliar damage and release of stress volatiles is highly dependent on stomatal openness and priming by low-level ozone exposure in Phaseolus vulgaris.

PubMed

Li, Shuai; Harley, Peter C; Niinemets, Ülo

2017-09-01

Acute ozone exposure triggers major emissions of volatile organic compounds (VOCs), but quantitatively, it is unclear how different ozone doses alter the start and the total amount of these emissions, and the induction rate of different stress volatiles. It is also unclear whether priming (i.e. pre-exposure to lower O 3 concentrations) can modify the magnitude and kinetics of volatile emissions. We investigated photosynthetic characteristics and VOC emissions in Phaseolus vulgaris following acute ozone exposure (600 nmol mol -1 for 30 min) under illumination and in darkness and after priming with 200 nmol mol -1 O 3 for 30 min. Methanol and lipoxygenase (LOX) pathway product emissions were induced rapidly, followed by moderate emissions of methyl salicylate (MeSA). Stomatal conductance prior to acute exposure was lower in darkness and after low O 3 priming than in light and without priming. After low O 3 priming, no MeSA and lower LOX emissions were detected under acute exposure. Overall, maximum emission rates and the total amount of emitted LOX products and methanol were quantitatively correlated with total stomatal ozone uptake. These results indicate that different stress volatiles scale differently with ozone dose and highlight the key role of stomatal conductance in controlling ozone uptake, leaf injury and volatile release. © 2017 John Wiley & Sons Ltd.

Ozone-induced foliar damage and release of stress volatiles is highly dependent on stomatal openness and priming by low-level ozone exposure in Phaseolus vulgaris

PubMed Central

Li, Shuai; Harley, Peter C.; Niinemets, Ülo

2018-01-01

Acute ozone exposure triggers major emissions of volatile organic compounds (VOC), but quantitatively, it is unclear how different ozone doses alter the start and the total amount of these emissions, and the induction rate of different stress volatiles. It is also unclear whether priming (i.e., pre-exposure to lower O3 concentrations) can modify the magnitude and kinetics of volatile emissions. We investigated photosynthetic characteristics and VOC emissions in Phaseolus vulgaris following acute ozone exposure (600 nmol mol-1 for 30 min) under illumination and in darkness and after priming with 200 nmol mol-1 O3 for 30 min. Methanol and lipoxygenase (LOX) pathway product emissions were induced rapidly, followed by moderate emissions of methyl salicylate (MeSA). Stomatal conductance prior to acute exposure was lower in darkness and after low O3 priming than in light and without priming. After low O3 priming, no MeSA and lower LOX emissions were detected under acute exposure. Overall, maximum emission rates and the total amount of emitted LOX products and methanol were quantitatively correlated with total stomatal ozone uptake. These results indicate that different stress volatiles scale differently with ozone dose and highlight the key role of stomatal conductance in controlling ozone uptake, leaf injury and volatile release. PMID:28623868

Radiation protocols determine acute graft-versus-host disease incidence after allogeneic bone marrow transplantation in murine models.

PubMed

Schwarte, Sebastian; Bremer, Michael; Fruehauf, Joerg; Sorge, Yanina; Skubich, Susanne; Hoffmann, Matthias W

2007-09-01

Effects of radiation sources used for total body irradiation (TBI) on Graft-versus-Host Disease (GvHD) induction were examined. In a T cell receptor (TCR) transgenic mouse model, single fraction TBI was performed with different radiation devices ((60)Cobalt; (137)Cesium; 6 MV linear accelerator), dose rates (0.85; 1.5; 2.9; 5 Gy/min) and total doses before allogeneic bone marrow transplantation (BMT). Recipients were observed for 120 days. Different tissues were examined histologically. Acute GvHD was induced by a dose rate of 0.85 Gy/min ((60)Cobalt) and a total dose of 9 Gy and injection of 5 x 10(5) lymph node cells plus 5 x 10(6) bone marrow cells. Similar results were obtained using 6 MV linear accelerator- (linac-) photons with a dose rate of 1.5 Gy/min and 0.85 Gy/min, a total dose of 9.5 Gy and injection of same cell numbers. TBI with (137)Cesium (dose rate: 2.5 Gy/min) did not lead reproducibly to lethal acute GvHD. Experimental TBI in murine models may induce different immunological responses, depending on total energy, total single dose and dose rate. GvHD might also be induced by TBI with low dose rates.

In vitro bactericidal activity of 465-470 nm blue light phototherapy and aminolevulinic acid on Staphylococcus pseudintermedius.

PubMed

Bae, Seulgi; Oh, Taeho

2018-05-30

Staphylococcus pseudintermedius is the principal pathogen causing bacterial skin infections in dogs. Photodynamic therapy (PDT) involving the combination of light and a topical photosensitizer is used to treat human skin infections. Although the antimicrobial effects of PDT have been demonstrated using in vivo and in vitro studies in humans, its effects on dogs and their pathogens are unclear. The aim of this study was to demonstrate the in vitro efficacy of PDT over a 465-470 nm spectrum to kill S. pseudintermedius using δ-aminolevulinic acid (ALA) as the photosensitizer. Six S. pseudintermedius isolates from canine skin were exposed to blue light-emitting diodes (LEDs) at 465-470 nm, with or without ALA. The light doses were 18.4, 36.8 and 55.2 J/cm 2 . The number of colony-forming units and optical densities of broth cultures were measured and then compared with Dunnett's test. Bacterial viability was monitored using fluorescence microscopy and the fluorescence intensity values were compared with a paired Student's t-test. Blue light inhibited the growth of S. pseudintermedius; the effect significantly increased with the addition of ALA as a photosensitizer and with increasing light doses. Live/dead staining confirmed that PDT reduced bacterial viability and exerted an antibacterial effect. Blue light has a strong antibacterial effect on S. pseudintermedius in a light dose-dependent manner. ALA alone did not exhibit bactericidal action, but its combination with blue light increased the effect of PDT compared to blue light alone. © 2018 ESVD and ACVD.

Television, computer, and video viewing; physical activity; and upper limb fracture risk in children: a population-based case control study.

PubMed

Ma, Deqiong; Jones, Graeme

2003-11-01

The effect of physical activity on upper limb fractures was examined in this population-based case control study with 321 age- and gender-matched pairs. Sports participation increased fracture risk in boys and decreased risk in girls. Television viewing had a deleterious dose response association with wrist and forearm fractures while light physical activity was protective. The aim of this population-based case control study was to examine the association between television, computer, and video viewing; types and levels of physical activity; and upper limb fractures in children 9-16 years of age. A total of 321 fracture cases and 321 randomly selected individually matched controls were studied. Television, computer, and video viewing and types and levels of physical activity were determined by interview-administered questionnaire. Bone strength was assessed by DXA and metacarpal morphometry. In general, sports participation increased total upper limb fracture risk in boys and decreased risk in girls. Gender-specific risk estimates were significantly different for total, contact, noncontact, and high-risk sports participation as well as four individual sports (soccer, cricket, surfing, and swimming). In multivariate analysis, time spent television, computer, and video viewing in both sexes was positively associated with wrist and forearm fracture risk (OR 1.6/category, 95% CI: 1.1-2.2), whereas days involved in light physical activity participation decreased fracture risk (OR 0.8/category, 95% CI: 0.7-1.0). Sports participation increased hand (OR 1.5/sport, 95% CI: 1.1-2.0) and upper arm (OR 29.8/sport, 95% CI: 1.7-535) fracture risk in boys only and decreased wrist and forearm fracture risk in girls only (OR 0.5/sport, 95% CI: 0.3-0.9). Adjustment for bone density and metacarpal morphometry did not alter these associations. There is gender discordance with regard to sports participation and fracture risk in children, which may reflect different approaches to sport. Importantly, television, computer, and video viewing has a dose-dependent association with wrist and forearm fractures, whereas light physical activity is protective. The mechanism is unclear but may involve bone-independent factors, or less likely, changes in bone quality not detected by DXA or metacarpal morphometry.

[Development of a monitor for quantifying personal eye exposure to visible and ultraviolet radiation and its application in epidemiology].

PubMed

Eto, Norihito; Tsubota, Kazuo; Tanaka, Taichiro; Nishiwaki, Yuji

2013-01-01

Eye diseases including cataract, keratitis and pterygium have been reported to be sun-exposure-related. The association between macular degeneration and blue light has also been discussed. Moreover, it is hypothesized that retinal exposure to blue light may influence the human circadian rhythm. However, no monitoring devices exist that can measure eye exposure to visible and ultraviolet (UV) radiation over time. To measure the exact dose at specific times, we have developed a novel sensing system (ray-sensing glass system: RaySeG). RaySeG can continuously measure and record the composition and intensity of light with a time-stamped system. Subjects wearing RaySeG were instructed to walk under various light conditions such as indoor and outdoor. RaySeG consists of two sensors embedded in the eyeglasses. These sensors are for UV (260-400 nm), visible lights (red, 615 nm; green, 540 nm; and blue, 465 nm: peak wavelength for each). The total weight of the system is about 100 g, and the size is comparable to that of a digital audio player. The system continuously recorded changes in visible and UV light exposure under various conditions. After accuracy validation, further experiments with a larger number of subjects are required. Our final goal is to apply the system to evaluating personal eye exposure to UV and visible light in epidemiological studies of eye diseases and circadian rhythm abnormality.

Intravenous Single-Dose Toxicity of Redaporfin-Based Photodynamic Therapy in Rodents

PubMed Central

Rocha, Luis B.; Schaberle, Fábio; Dąbrowski, Janusz M.; Simões, Sérgio; Arnaut, Luis G.

2015-01-01

We assessed the tolerability and safety in rodents of a single intravenous (i.v.) dose of redaporfin, a novel photosensitizer for Photodynamic Therapy (PDT) of cancer. Two approaches were used to evaluate acute toxicity: (i) a dose escalation study in BALB/c mice to evaluate the maximum tolerated dose of redaporfin; and (ii) a safety toxicology study in Wistar rats, of a single dose of redaporfin, with or without illumination, to evaluate possible signs of systemic toxicity. Redaporfin formulation was well tolerated by mice, with no signs of adverse reactions up to 75 mg/kg. In rats, there were no relevant changes, except for a significant, but transient, increase in the blood serum markers for hepatic function and muscle integrity, and also on neutrophil counts, observed after the application of light. The overall results showed that redaporfin-PDT is very well tolerated. No abnormalities were observed, including reactions at the injection site or skin phototoxicity, although the animals were maintained in normal indoor lighting. Redaporfin also showed a high efficacy in the treatment of male BALB/c mice with subcutaneously implanted colon (CT26) tumours. Vascular-PDT with 1.5 mg/kg redaporfin and a light dose of 74 J/cm2 led to the complete tumour regression in 83% of the mice. PMID:26670231

Ultraviolet radiation exposure of children and adolescents in Durban, South Africa.

PubMed

Guy, Caradee; Diab, Roseanne; Martincigh, Bice

2003-03-01

The solar ultraviolet radiation (UVR) exposure of 30 children and adolescents in three age groups (4-6 years, 7-9 years and 13-14 years) was measured for 1 week in late summer (February-March) in Durban, South Africa, using UVR-sensitive polysulfone film badges (PSFB) attached to the lapel region of the body. The mean and median values for all ages over the study period were 2.0 and 1.2 standard erythemal dose (SED) units, respectively, where 1 SED = 100 J x m(-2). Individual PSFB doses were analyzed as a function of age, gender and behavior. No significant statistical differences were found between different age groups; however, there was a statistical difference between males and females, with males generally receiving higher PSFB doses. Subjects completed UVR exposure journals documenting their time outdoors, shade versus sun conditions, nature of their activities, clothing worn and their use of sunscreen for each day of the study. Activity patterns were noted as the most important factor influencing individual UVR dose. Ambient erythemal UVR was measured by a Yankee Environmental Systems UVB pyranometer, and a relationship between ambient UVR and individual UVR dose was derived. On average, subjects received a dose of 4.6% of the total daily erythemal UVR. Based on this factor, the potential dose of an individual over a full annual cycle was estimated. Accordingly, there were 139 days during the year when an individual with skin type I (light skin) would be likely to experience minimal erythema and 97 and 32 days for individuals with skin types II and III, respectively.

Characterization of a fiber-coupled Al2O3:C luminescence dosimetry system for online in vivo dose verification during 192Ir brachytherapy.

PubMed

Andersen, Claus E; Nielsen, Søren Kynde; Greilich, Steffen; Helt-Hansen, Jakob; Lindegaard, Jacob Christian; Tanderup, Kari

2009-03-01

A prototype of a new dose-verification system has been developed to facilitate prevention and identification of dose delivery errors in remotely afterloaded brachytherapy. The system allows for automatic online in vivo dosimetry directly in the tumor region using small passive detector probes that fit into applicators such as standard needles or catheters. The system measures the absorbed dose rate (0.1 s time resolution) and total absorbed dose on the basis of radioluminescence (RL) and optically stimulated luminescence (OSL) from aluminum oxide crystals attached to optical fiber cables (1 mm outer diameter). The system was tested in the range from 0 to 4 Gy using a solid-water phantom, a Varian GammaMed Plus 192Ir PDR afterloader, and dosimetry probes inserted into stainless-steel brachytherapy needles. The calibrated system was found to be linear in the tested dose range. The reproducibility (one standard deviation) for RL and OSL measurements was 1.3%. The measured depth-dose profiles agreed well with the theoretical expectations computed with the EGSNRC Monte Carlo code, suggesting that the energy dependence for the dosimeter probes (relative to water) is less than 6% for source-to-probe distances in the range of 2-50 mm. Under certain conditions, the RL signal could be greatly disturbed by the so-called stem signal (i.e., unwanted light generated in the fiber cable upon irradiation). The OSL signal is not subject to this source of error. The tested system appears to be adequate for in vivo brachytherapy dosimetry.

Real-time colour pictorial radiation monitoring during coronary angiography: effect on patient peak skin and total dose during coronary angiography.

PubMed

Wilson, Sharon M; Prasan, Ananth M; Virdi, Amy; Lassere, Marissa; Ison, Glenn; Ramsay, David R; Weaver, James C

2016-10-10

The aim of this study was to evaluate whether a real-time (RT) colour pictorial radiation dose monitoring system reduces patient skin and total radiation dose during coronary angiography and intervention. Patient demographics, procedural variables and radiation parameters were recorded before and after institution of the RT skin dose recording system. Peak skin dose as well as traditionally available measures of procedural radiation dose were compared. A total of 1,077 consecutive patients underwent coronary angiography, of whom 460 also had PCI. Institution of the RT skin dose recording system resulted in a 22% reduction in peak skin dose after accounting for confounding variables. Radiation dose reduction was most pronounced in those having PCI but was also seen over a range of subgroups including those with prior coronary artery bypass surgery, high BMI, and with radial arterial access. This was associated with a significant reduction in the number of patients placed at risk of skin damage. Similar reductions in parameters reflective of total radiation dose were also demonstrated after institution of RT radiation monitoring. Institution of an RT skin dose recording reduced patient peak skin and total radiation dose during coronary angiography and intervention. Consideration should be given to widespread adoption of this technology.

Hematopoietic stimulation by porphyrin photosensitizers (Invited Paper)

NASA Astrophysics Data System (ADS)

Levy, Julia G.; Hunt, David W. C.; Mitchell, David W.; Jamieson, Catriona H. M.

1992-06-01

The effects of the photosensitizers, PhotofrinTM and benozoporphyrin derivative monoacid ring A (BPD) on a variety of hematopoietic cell functions have been studied, both in the presence and absence of light activation. A marked increase in hematopoiesis was observed in the bone marrow and spleens of DBA/2 mice administered high dose Photofrin but not BPD. This was manifested in an increased relative spleen weight, nucleated spleen cell number and circulating white blood cell concentration 7 days following Photofrin injection. We have shown that BPD and light doses just below phototoxic ranges stimulate the growth of human colony forming committed myeloid progenitors as well as pluripotent stem cells grown in long term marrow culture. Studies on the effect of BPD on the function of T lymphocytes in the absence of light has also demonstrated a stimulatory effect. The dose range in which this is observed is considerably broader than that observed with light activation. The mechanisms involved in this stimulatory effect have been studied and are discussed.

The effects of a selective 5-HT2 receptor antagonist (ICI 170,809) on platelet aggregation and pupillary responses in healthy volunteers.

PubMed Central

Millson, D S; Jessup, C L; Swaisland, A; Haworth, S; Rushton, A; Harry, J D

1992-01-01

1. ICI 170,809 (2-(2-dimethylamino-2-methylpropylthio)-3-phenylquinoline hydrochloride) is a potent 5-hydroxytryptamine (5-HT) type 2 postsynaptic receptor antagonist. 2. Effects of ICI 170,809 as single oral doses (3, 7, 15 and 30 mg) or placebo were studied on the duration of antagonism for the ex vivo platelet aggregatory response to 5-HT and to the pupillary light constrictor response in eight healthy male volunteers. 3. Pupillary dark adapted responses to a 0.5 s light stimulus were measured using a portable infrared pupillometer, for up to 24 h after dosing. 4. The in vitro platelet 5-HT aggregation response was reduced by ICI 170,809, with depression of the dose-response curve to 5-HT at all concentrations of 5-HT and with no evidence for a parallel shift. 5. The ex vivo platelet 5-HT response demonstrated a dose related significant (P less than 0.02) decrease in aggregation reaching a maximum at 2 h after dosing with the effect persisting for at least 8 h after dosing with the 7 and 15 mg doses. 6. Resting pupil diameter (RPD), and light induced pupillary responses in the dark adapted pupil, showed a significant (P less than 0.01) dose related reduction with significant (P less than 0.05) effects still present with the 15 and 30 mg doses at 8 h after dosing. 7. We conclude that, changes in both ex vivo platelet aggregation to 5-HT and dark adapted pupil size, are significantly correlated (P less than 0.0001) with log plasma concentrations (ng ml-1) of ICI 170,809, enabling the assessment of 5-HT2-receptor antagonism in man. PMID:1576048

European light dosimeter network (ELDONET): 1998 data

NASA Astrophysics Data System (ADS)

Häder, D.-P.; Lebert, M.; Colombetti, G.; Figueroa, F.

2001-03-01

The European light dosimeter network of over 40 stations has been established in Europe and other continents equipped with three-channel filter dosimeters to measure solar radiation in three channels, UV-B (280-315 nm), UV-A (315-400 nm) and photosynthetically active radiation (PAR). The recorded data have been evaluated, and the monthly doses in all three channels show a strong latitudinal dependence from northern Sweden to the Canary Islands. There are a few remarkable exceptions such as the data recorded at the high mountain station on the Zugspitze (German Alps) and unequal doses at stations at comparable latitudes which indicate the impact of local weather conditions and mean sunshine hours. While generally peak values are recorded in the months of June and July, the UV-B maxima are shifted later into the year, which is due to the antagonistic functions of decreasing solar angles and increasing transparency of the atmosphere as the total column ozone decreases in the second half of the year for the Northern Hemisphere. This is supported by comparison with modelled total column ozone and satellite-based measurements. Also the ratios of UV-B:UV-A and UV-B:PAR as well as UV-A:PAR peak during the summer months, with the exception of the northernmost station at Abisko (north Sweden) where the UV-A:PAR ratio peaks in the winter months which is due to the specific photoclimatic conditions north of the polar circle. The penetration of solar radiation into the water column was found to strongly depend on the transparency of the water column. In Gran Canaria more than 10% of the surface UV-B penetrated to 4-5 m depth. The path of the solar eclipse on 11 August 1999 could be followed in several stations with different degrees of occlusion of the sun disk.

Antibacterial effect of 405±5nm light emitting diode illumination against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella on the surface of fresh-cut mango and its influence on fruit quality.

PubMed

Kim, Min-Jeong; Tang, Chee Hwa; Bang, Woo Suk; Yuk, Hyun-Gyun

2017-03-06

To investigate a potential of 405±5nm light emitting diode (LED) as a novel technology for food preservation, the antibacterial effect of 405±5nm LED on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella spp. on the surface of fresh-cut mango and its influence on fruit quality were evaluated at different storage temperatures. LED-illumination inactivated 1.0-1.6 logCFU/cm 2 of populations at 4 and 10°C for 36-48h (total dose, 2.6-3.5kJ/cm 2 ) regardless of bacterial species, while those on non-illuminated mange remained unchanged or slightly increased during storage. At 20°C for 24h (total dose, 1.7kJ/cm 2 ), non-illuminated E. coli O157:H7 and Salmonella gradually grew, whereas LED-illumination reduced 1.2 log of Salmonella and inhibited the growth of E. coli O157:H7. Unlike these, non-illuminated L. monocytogenes cells rapidly increased to 7.3 log, while illuminated cells reached 4.6 log, revealing that LED-illumination delayed their growth. There were no significant (P>0.05) differences in color, antioxidant capacity, ascorbic acid, β-carotene, and flavonoid between non-illuminated and illuminated cut mangoes, regardless of storage temperature. These results suggest that 405±5nm LEDs in combination with chilling temperatures could be applied to preserve fresh-cut fruits without deterioration of physicochemical quality of fruits at food establishments, minimizing the risk of foodborne disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Prolonged exposure to a low-dose of bisphenol A increases spontaneous motor activity in adult male rats.

PubMed

Nojima, Kazuo; Takata, Tomoyo; Masuno, Hiroshi

2013-07-01

We investigated the effects of bisphenol A (BPA), an environmental endocrine-disrupting chemical, on spontaneous motor activity in adult male rats. The rats were implanted intraperitoneally with mini-osmotic pumps containing either BPA (50 μg/kg body weight per day) in sesame oil (BPA-treated group) or sesame oil only (vehicle-treated group). Spontaneous motor activity during a 24-h period was measured over 5 days from day 9 to day 13 after implantation using an animal movement analysis system. Spontaneous motor activity during the last 2 h of the dark phase and during the first 1-h of the light phase was increased in the BPA-treated group. Total spontaneous motor activity during the 12-h light phase, but not the 12-h dark phase, was higher in the BPA-treated group than in the vehicle-treated group. These findings suggest that BPA may induce hyperactivity in adult male rats during the 12-h light phase, especially during the 2 h immediately preceding sleep-onset and 1 h immediately following sleep-onset.

Effectiveness of UV-C light irradiation on disinfection of an eSOS(®) smart toilet evaluated in a temporary settlement in the Philippines.

PubMed

Zakaria, Fiona; Harelimana, Bertin; Ćurko, Josip; van de Vossenberg, Jack; Garcia, Hector A; Hooijmans, Christine Maria; Brdjanovic, Damir

2016-01-01

Ultraviolet germicidal (short wavelength UV-C) light was studied as surface disinfectant in an Emergency Sanitation Operation System(®) smart toilet to aid to the work of manual cleaning. The UV-C light was installed and regulated as a self-cleaning feature of the toilet, which automatically irradiate after each toilet use. Two experimental phases were conducted i.e. preparatory phase consists of tests under laboratory conditions and field testing phase. The laboratory UV test indicated that irradiation for 10 min with medium-low intensity of 0.15-0.4 W/m(2) could achieve 6.5 log removal of Escherichia coli. Field testing of the toilet under real usage found that UV-C irradiation was capable to inactivate total coliform at toilet surfaces within 167-cm distance from the UV-C lamp (UV-C dose between 1.88 and 2.74 mW). UV-C irradiation is most effective with the support of effective manual cleaning. Application of UV-C for surface disinfection in emergency toilets could potentially reduce public health risks.

Photodynamic therapy for early malignancies in the lower female genital tract

NASA Astrophysics Data System (ADS)

Lobraico, Rocco V.

1990-09-01

A total of 14 patients who had failed all conventional modalities for cancer of the vulva vagina and perianal area were treated with photodynamic therapy PDT. The affinity of porphyrins to neopJ. astic tissue enables treatment to be concentrated at the tumor site. An Aurora FL Argon pumped dye laser (Cooper LaserSonics Inc. USA) was used to pump dicyanomethylene dye as an activating source for a red light at a wavelength of 630 nm. The combination of a tumor localizing photosensitizer and photoactivating red light produces a photo chemical reaction that is destructive to the cancerous lesion. The treatment time varied between 10-30 minutes. Vulvar sites ranged from 9-38 cm2. Delivered light doses were from 50-125 J/cm2 and power density from 50 to 75 mW/cm2. A complete response was obtained in 80 of the sites treated as evidenced by negative biopsies taken at 3 months post treatment. Adverse reactions to PDT included a transient cutaneous photosensitivity due to retention of the photosensitizers in the skin. This reaction usually persisted from 45-60 days. 1.

The phase shift hypothesis for the circadian component of winter depression

PubMed Central

Lewy, Alfred J.; Rough, Jennifer N.; Songer, Jeannine B.; Mishra, Neelam; Yuhas, Krista; Emens, Jonathan S.

2007-01-01

The finding that bright light can suppress melatonin production led to the study of two situations, indeed, models, of light deprivation: totally blind people and winterdepressives. The leading hypothesis for winter depression (seasonal affective disorder, or SAD) is the phase shift hypothesis (PSH). The PSH was recently established in a study in which SAD patients were given low-dose melatonin in the afternoon/evening to cause phase advances, or in the morning to cause phase delays, or placebo. The prototypical phase-delayed patient as well as the smaller subgroup of phase-advanced patients, optimally responded to melatonin given at the correct time. Symptom severity improved as circadian misalignment was corrected. Orcadian misalignment is best measured as the time interval between the dim light melatonin onset (DLMO) and mid-sleep. Using the operational definition of the plasma DLMO as the interpolated time when melatonin levels continuously rise above the threshold of 10 pglmL, the average interval between DLMO and mid-sleep in healthy controls is 6 hours, which is associated with optimal mood in SAD patients. PMID:17969866

Bacteriostatic influence of red laser light on the growth of Staphylococcus aureus and photodynamic enhancement of this effect with Photoditazine

NASA Astrophysics Data System (ADS)

Egorova, A. V.; Brill, G. E.; Bugaeva, I. O.; Tuchina, E. S.; Ponomaryov, G. V.; Ushakova, O. V.

2018-04-01

The influence of red laser irradiation on the growth of colonies of Staphylococcus aureus and photodynamic effect of the photosensitizer Photoditazine were performed. It was established that the emission of red laser light caused an inhibition of bacterial growth. This effect on standard strain of Staphylococcus aureus was evident only when relatively high doses of radiation (180 j/cm2). Photosensitivity of the methicillin-resistant strains was much higher: bacteriostatic effect of red light was observed already at the dose of 60 j/cm2 . Pre-treatment of bacterial cells by Photoditazine significantly enhances the inhibitory effect of the laser light.

Diclofenac-Induced Photo-Onycholysis

PubMed Central

Al-Kathiri, Lutfi; Al-Asmaili, Abla

2016-01-01

Onycholysis is the detachment of the nail plate from the nail bed. If drug-induced, it can be an isolated phenomenon, but it may also accompany or follow a cutaneous phototoxicity reaction due to drug intake and exposure to ultraviolet irradiation. Photo-onycholysis is a rare photosensitivity reaction due to exposure to either a natural or artificial source of light. Many drugs are responsible for this phototoxic reaction, especially tetracyclines, psoralens, chloramphenicol, non-steroidal anti-inflammatory drugs, fluoroquinolones, and, rarely, doxycycline. Any patient given enough of a therapeutic dose of an inducing drug and sufficient light irradiation can develop phototoxic reactions. While there is no need to avoid these drugs completely, precautions should be taken. Here we have reported the case of a patient who developed onycholysis of his fingernails with sparing of the toenails following administration of diclofenac therapy for lower back pain. The onycholysis was associated with a phototoxic reaction. The swellings resolved totally within two days, and the patient started to notice the separation of all fingernail plates from their nail beds. The patient was treated symptomatically. On follow-up, onycholysis had regressed slowly, and the condition recovered totally within three months without any sequelae. PMID:26816569

Biophysical characterization of influenza virus subpopulations using field flow fractionation and multiangle light scattering: correlation of particle counts, size distribution and infectivity.

PubMed

Wei, Ziping; McEvoy, Matt; Razinkov, Vladimir; Polozova, Alla; Li, Elizabeth; Casas-Finet, Jose; Tous, Guillermo I; Balu, Palani; Pan, Alfred A; Mehta, Harshvardhan; Schenerman, Mark A

2007-09-01

Adequate biophysical characterization of influenza virions is important for vaccine development. The influenza virus vaccines are produced from the allantoic fluid of developing chicken embryos. The process of viral replication produces a heterogeneous mixture of infectious and non-infectious viral particles with varying states of aggregation. The study of the relative distribution and behavior of different subpopulations and their inter-correlation can assist in the development of a robust process for a live virus vaccine. This report describes a field flow fractionation and multiangle light scattering (FFF-MALS) method optimized for the analysis of size distribution and total particle counts. The FFF-MALS method was compared with several other methods such as transmission electron microscopy (TEM), atomic force microscopy (AFM), size exclusion chromatography followed by MALS (SEC-MALS), quantitative reverse transcription polymerase chain reaction (RT Q-PCR), median tissue culture dose (TCID(50)), and the fluorescent focus assay (FFA). The correlation between the various methods for determining total particle counts, infectivity and size distribution is reported. The pros and cons of each of the analytical methods are discussed.

Are there mechanistic differences between ultraviolet and visible radiation induced skin pigmentation?

PubMed

Ramasubramaniam, Rajagopal; Roy, Arindam; Sharma, Bharati; Nagalakshmi, Surendra

2011-12-01

Most of the studies on sunlight-induced pigmentation of skin are mainly focused on ultraviolet (UV) radiation-induced pigmentation and ways to prevent it. Recent studies have shown that the visible component of sunlight can also cause significant skin pigmentation. In the current study, the extent of pigmentation induced by UV and visible regions of sunlight in subjects with Fitzpatrick skin type IV-V was measured and compared with pigmentation induced by total sunlight. The immediate pigment darkening (IPD) induced by the visible fraction of sunlight is not significantly different from that induced by the UV fraction. However, the persistent pigment darkening (PPD) induced by visible fraction of sunlight in significantly lower than that induced by the UV fraction. The dose responses of IPD induced by UV, visible light and total sunlight suggest that both UV and visible light interact with the same precursor although UV is 25 times more efficient in inducing pigmentation per J cm(-2) of irradiation compared to visible radiation. The measured diffused reflection spectra and decay kinetics of UV and visible radiation-induced pigmentation are very similar, indicating that the nature of the transient and persistent species involved in both the processes are also likely to be same.

Current status and performance of the BESIII electromagnetic calorimeter

NASA Astrophysics Data System (ADS)

Fang, Jian; Wang, Zhigang

2012-12-01

The design and construction of the BESIII electromagnetic calorimeter is introduced briefly. Radiation dose of CsI(Tl) crystals is monitored and history graph of integral dose of crystals is showed. LED-fiber system is used for monitoring the EMC light output, and large decrease of light output of several crystals is discussed. BESIII electromagnetic calorimeter works very well and its performance reach the design value.

Variation of rabbit sperm physiologic parameters after the X-ray exposure.

PubMed

Klepko, A V; Gorban, L V; Motryna, O A; Kondratova, Y A; Chernyshov, A V; Andreychenko, S V

2013-01-01

To study the impact of X-irradiation on the morpho-functional characteristics of rabbit spermatozoa and the contents of fructose, L-carnitine, α-tocopherol, ascorbate and citrate in the animal sperm. The total body irradiation of rabbits (Soviet Shinchilla) was performed at the RUM-17 device in the dose range of 1.0-7.0 Gy with 2.8·10-3 Gy/sec intensity. The animal sperm was collected by the artificial vagina and then separated on seminal plasma and spermatozoa through centrifugation. Sperm concentration, motility, morphology and linear velocity were identified using the "MBI-6" light microscope. The quantitative determination of ascorbate, α-tocopherol and L-carnitine in seminal plasma was made on the "Agilent 1200" liquid chromatograph, while the concentration of fructose and citrate was measured on a spectrophotometer. The X-ray irradiation was shown to cause a dose-dependent suppressing effect on the prostate, seminal vesicles and epididymices expresed through the decreased content of fructose, citrate, L-carnitine, α-tocopherol and ascorbate in a rabbit sperm. Simultaneously the exacerbation of morphologic anomalies (damage of acrosomes, heads and tails) in spermatozoa along with spermatozoid motility and linear velocity decrease were elucidated. The run-time pattern of morpho-functional changes in spermatozoa together with component content of rabbit sperm in response to the total body irradiation was studied. Consequently the dose dependent raise of morphologic anomalies (damage of acrosomes, heads and tails) in spermatozoa and the slowing of spermatozoid linear velocity was found out. The sperm capacity to fulfill the post-radiation recovery was proven up. The effectiveness of the latter was shown to be dependent upon the radiation dose absorbed and the duration of post-irradiation period. Klepko A. V., Gorban L. V., Motryna O. A., Kondratova Ju. A., Chernyshov A. V., Andrejchenko S. V., 2013.

Analgesic effects of oligonol, acupuncture and quantum light therapy on chronic nonbacterial prostatitis.

PubMed

Akdere, Hakan; Oztekin, Ilhan; Arda, Ersan; Aktoz, Tevfik; Turan, Fatma Nesrin; Burgazli, Kamil Mehmet

2015-04-01

Chronic Nonbacterial Prostatitis (CNBP) is a condition that frequently causes long-term pain and a significant decrease in the quality of life. The present study aimed to examine the analgesic effects of oligonol, acupuncture, quantum light therapy and their combinations on estrogen-induced CNBP in rats. This experimental study was conducted in Edirne, Turkey, using a simple randomized allocation. A total of 90 adult male Wistar rats were randomized into 9 groups of 10 rats each: Group I, control; Group II, CNBP, Group III, oligonol only, Group IV, acupuncture only; Group V, quantum only; Group VI, oligonol + quantum; Group VII, acupuncture + oligonol; Group VIII, quantum + acupuncture; Group IX, acupuncture + quantum + oligonol. Oligonol treatment was given at a dose of 60 mg/day for 6 weeks. Conceptual vessels (CV) 3 and 4, and bilaterally urinary bladder (Bl) 32 and 34 points were targeted with 1-hour acupuncture stimulation. The quantum light therapy was applied in 5-minute sessions for 6 weeks (3-times/a week). For pain measurements, mechanical pressure was applied to a point 2 cm distal to the root of the tail to elicit pain and consequent parameters (peak force, latency time of response and total length of measurement) were assessed. Analgesic effects were observed with all treatment regimens; however, the most prominent median analgesic effect was shown in the quantum light therapy in combination with acupuncture for estrogen-induced CNBP (PF1 = 663.9, PF2 = 403.4) (P = 0.012). Furthermore, we observed that monotherapy with quantum light showed a better analgesic efficacy as compared to oligonol and acupuncture monotherapies (PF1 = 1044.6, PF2 = 661.2) (P = 0.018, P = 0.008, P = 0.018; respectively). All treatment modalities showed a significant analgesic effect on CNBP in rats, being most prominent with the quantum light therapy.

The effects of UV radiation during the vegetative period on antioxidant compounds and postharvest quality of broccoli (Brassica oleracea L.).

PubMed

Topcu, Yasin; Dogan, Adem; Kasimoglu, Zehra; Sahin-Nadeem, Hilal; Polat, Ersin; Erkan, Mustafa

2015-08-01

In this study, the effects of supplementary UV radiation during the vegetative period on antioxidant compounds, antioxidant activity and postharvest quality of broccoli heads during long term storage was studied. The broccolis were grown under three different doses of supplementary UV radiation (2.2, 8.8 and 16.4 kJ/m(2)/day) in a soilless system in a glasshouse. Harvested broccoli heads were stored at 0 °C in modified atmosphere packaging for 60 days. The supplementary UV radiation (280-315 nm) during the vegetative period significantly decreased total carotenoid, the chlorophyll a and chlorophyll b content but increased the ascorbic acid, total phenolic and flavonoid contents of broccolis. All supplementary UV treatments slightly reduced the antioxidant activity of the broccolis, however, no remarkable change was observed between 2.2 and 8.8 kJ/m(2) radiation levels. The sinigrin and glucotropaeolin contents of the broccolis were substantially increased by UV treatments. The prolonged storage period resulted in decreased ascorbic acid, total phenolic and flavonoid contents, as well as antioxidant activity. Discoloration of the heads, due to decreased chlorophyll and carotenoid contents, was also observed with prolonged storage duration. Glucosinolates levels showed an increasing tendency till the 45th day of storage, and then their levels started to decline. The weight loss of broccoli heads during storage progressively increased with storage time in all treatments. Total soluble solids, solids content and titratable acidity decreased continuously during storage. Titratable acidity was not affected by UV radiation doses during the storage time whereas soluble solids and solids content (dry matter) were significantly affected by UV doses. Supplementary UV radiation increased the lightness (L*) and chroma (C*) values of the broccoli heads. Pre-harvest UV radiation during vegetative period seems to be a promising tool for increasing the beneficial health components of broccolis. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A single dose of alcohol does not meaningfully alter circadian phase advances and phase delays to light in humans

PubMed Central

Rizvydeen, Muneer; Fogg, Louis F.; Keshavarzian, Ali

2016-01-01

Central circadian timing influences mental and physical health. Research in nocturnal rodents has demonstrated that when alcohol is consumed, it reaches the central hypothalamic circadian pacemaker (suprachiasmatic nuclei) and can directly alter circadian phase shifts to light. In two separate studies, we examined, for the first time, the effects of a single dose of alcohol on circadian phase advances and phase delays to light in humans. Two 23-day within-subjects placebo-controlled counterbalanced design studies were conducted. Both studies consisted of 6 days of fixed baseline sleep to stabilize circadian timing, a 2-day laboratory session, a 6-day break, and a repeat of 6 days of fixed sleep and a 2-day laboratory session. In the phase advance study (n = 10 light drinkers, 24–45 yr), the laboratory sessions consisted of a baseline dim light phase assessment, sleep episode, alcohol (0.6 g/kg) or placebo, 2-h morning bright light pulse, and final phase assessment. In the phase-delay study (n = 14 light drinkers, 22–44 yr), the laboratory sessions consisted of a baseline phase assessment, alcohol (0.8 g/kg) or placebo, 2-h late night bright light pulse, sleep episode, and final phase assessment. In both studies, alcohol either increased or decreased the observed phase shifts to light (interaction P ≥ 0.46), but the effect of alcohol vs. placebo on phase shifts to light was always on average smaller than 30 min. Thus, no meaningful effects of a single dose of alcohol vs. placebo on circadian phase shifts to light in humans were observed. PMID:26936778

A single dose of alcohol does not meaningfully alter circadian phase advances and phase delays to light in humans.

PubMed

Burgess, Helen J; Rizvydeen, Muneer; Fogg, Louis F; Keshavarzian, Ali

2016-04-15

Central circadian timing influences mental and physical health. Research in nocturnal rodents has demonstrated that when alcohol is consumed, it reaches the central hypothalamic circadian pacemaker (suprachiasmatic nuclei) and can directly alter circadian phase shifts to light. In two separate studies, we examined, for the first time, the effects of a single dose of alcohol on circadian phase advances and phase delays to light in humans. Two 23-day within-subjects placebo-controlled counterbalanced design studies were conducted. Both studies consisted of 6 days of fixed baseline sleep to stabilize circadian timing, a 2-day laboratory session, a 6-day break, and a repeat of 6 days of fixed sleep and a 2-day laboratory session. In the phase advance study (n= 10 light drinkers, 24-45 yr), the laboratory sessions consisted of a baseline dim light phase assessment, sleep episode, alcohol (0.6 g/kg) or placebo, 2-h morning bright light pulse, and final phase assessment. In the phase-delay study (n= 14 light drinkers, 22-44 yr), the laboratory sessions consisted of a baseline phase assessment, alcohol (0.8 g/kg) or placebo, 2-h late night bright light pulse, sleep episode, and final phase assessment. In both studies, alcohol either increased or decreased the observed phase shifts to light (interaction P≥ 0.46), but the effect of alcohol vs. placebo on phase shifts to light was always on average smaller than 30 min. Thus, no meaningful effects of a single dose of alcohol vs. placebo on circadian phase shifts to light in humans were observed. Copyright © 2016 the American Physiological Society.

Fractional Third and Fourth Dose of RTS,S/AS01 Malaria Candidate Vaccine: A Phase 2a Controlled Human Malaria Parasite Infection and Immunogenicity Study.

PubMed

Regules, Jason A; Cicatelli, Susan B; Bennett, Jason W; Paolino, Kristopher M; Twomey, Patrick S; Moon, James E; Kathcart, April K; Hauns, Kevin D; Komisar, Jack L; Qabar, Aziz N; Davidson, Silas A; Dutta, Sheetij; Griffith, Matthew E; Magee, Charles D; Wojnarski, Mariusz; Livezey, Jeffrey R; Kress, Adrian T; Waterman, Paige E; Jongert, Erik; Wille-Reece, Ulrike; Volkmuth, Wayne; Emerling, Daniel; Robinson, William H; Lievens, Marc; Morelle, Danielle; Lee, Cynthia K; Yassin-Rajkumar, Bebi; Weltzin, Richard; Cohen, Joe; Paris, Robert M; Waters, Norman C; Birkett, Ashley J; Kaslow, David C; Ballou, W Ripley; Ockenhouse, Christian F; Vekemans, Johan

2016-09-01

Three full doses of RTS,S/AS01 malaria vaccine provides partial protection against controlled human malaria parasite infection (CHMI) and natural exposure. Immunization regimens, including a delayed fractional third dose, were assessed for potential increased protection against malaria and immunologic responses. In a phase 2a, controlled, open-label, study of healthy malaria-naive adults, 16 subjects vaccinated with a 0-, 1-, and 2-month full-dose regimen (012M) and 30 subjects who received a 0-, 1-, and 7-month regimen, including a fractional third dose (Fx017M), underwent CHMI 3 weeks after the last dose. Plasmablast heavy and light chain immunoglobulin messenger RNA sequencing and antibody avidity were evaluated. Protection against repeat CHMI was evaluated after 8 months. A total of 26 of 30 subjects in the Fx017M group (vaccine efficacy [VE], 86.7% [95% confidence interval [CI], 66.8%-94.6%]; P < .0001) and 10 of 16 in the 012M group (VE, 62.5% [95% CI, 29.4%-80.1%]; P = .0009) were protected against infection, and protection differed between schedules (P = .040, by the log rank test). The fractional dose boosting increased antibody somatic hypermutation and avidity and sustained high protection upon rechallenge. A delayed third fractional vaccine dose improved immunogenicity and protection against infection. Optimization of the RTS,S/AS01 immunization regimen may lead to improved approaches against malaria. NCT01857869. Published by Oxford University Press on behalf of the Infectious Diseases Society of America, 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Detecting and locating light atoms from high-resolution STEM images: The quest for a single optimal design.

PubMed

Gonnissen, J; De Backer, A; den Dekker, A J; Sijbers, J; Van Aert, S

2016-11-01

In the present paper, the optimal detector design is investigated for both detecting and locating light atoms from high resolution scanning transmission electron microscopy (HR STEM) images. The principles of detection theory are used to quantify the probability of error for the detection of light atoms from HR STEM images. To determine the optimal experiment design for locating light atoms, use is made of the so-called Cramér-Rao Lower Bound (CRLB). It is investigated if a single optimal design can be found for both the detection and location problem of light atoms. Furthermore, the incoming electron dose is optimised for both research goals and it is shown that picometre range precision is feasible for the estimation of the atom positions when using an appropriate incoming electron dose under the optimal detector settings to detect light atoms. Copyright © 2016 Elsevier B.V. All rights reserved.

Quality assurance in proton beam therapy using a plastic scintillator and a commercially available digital camera.

PubMed

Almurayshid, Mansour; Helo, Yusuf; Kacperek, Andrzej; Griffiths, Jennifer; Hebden, Jem; Gibson, Adam

2017-09-01

In this article, we evaluate a plastic scintillation detector system for quality assurance in proton therapy using a BC-408 plastic scintillator, a commercial camera, and a computer. The basic characteristics of the system were assessed in a series of proton irradiations. The reproducibility and response to changes of dose, dose-rate, and proton energy were determined. Photographs of the scintillation light distributions were acquired, and compared with Geant4 Monte Carlo simulations and with depth-dose curves measured with an ionization chamber. A quenching effect was observed at the Bragg peak of the 60 MeV proton beam where less light was produced than expected. We developed an approach using Birks equation to correct for this quenching. We simulated the linear energy transfer (LET) as a function of depth in Geant4 and found Birks constant by comparing the calculated LET and measured scintillation light distribution. We then used the derived value of Birks constant to correct the measured scintillation light distribution for quenching using Geant4. The corrected light output from the scintillator increased linearly with dose. The system is stable and offers short-term reproducibility to within 0.80%. No dose rate dependency was observed in this work. This approach offers an effective way to correct for quenching, and could provide a method for rapid, convenient, routine quality assurance for clinical proton beams. Furthermore, the system has the advantage of providing 2D visualization of individual radiation fields, with potential application for quality assurance of complex, time-varying fields. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

In vivo sampling of Verteporfin uptake in pancreas cancer xenograft models: comparison of surface, oral, and interstitial measurements

NASA Astrophysics Data System (ADS)

Isabelle, Martin; O'Hara, Julia A.; Samkoe, Kimberley S.; Hoopes, P. Jack; Mosse, Sandy; Pereira, Stephen; Hasan, Tayyaba; Pogue, Brian W.

2010-02-01

Photodynamic therapy (PDT) mediated with Verteporfin is being investigated as a pancreatic cancer treatment in the cases for non-surgical candidates. Tissue response to PDT is based on a number of parameters including photosensitizer (PS) dose, light dose and time interval between light application and PS injection. In this study, PS uptake and distribution in animal leg muscle, oral cavity tissues, pancreas and tumor was measured in vivo using light-induced fluorescence spectroscopy (LIFS) via an Aurora Optics Inc. PDT fluorescence dosimeter. An orthotopic pancreatic cancer model (AsPC-1) was implanted in SCID mice and treated with the PS. Probe measurements were made using a surface probe and an interstitial needle probe before and up to one hour after intravenous tail vein injection of the PS. The study demonstrated that it is possible to correlate in-vivo LIFS measurements of the PS uptake in the pancreas with measurements taken from the oral cavity indicating that light dosimetry of PDT of the pancreas can be ascertained from the LIFS measurements in the oral cavity. These results emphasize the importance of light dosimetry in improving the therapeutic outcome of PDT through light dose adaptation to the relative in situ tissue PS concentration.

Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

NASA Technical Reports Server (NTRS)

Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

1989-01-01

The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

[Exposure to toxic dose of adrenaline on the functional state of the liver].

PubMed

Kopylova, S V; Vlasova, K M; Anashkina, A A

2017-01-01

The blood biochemical parameters characterizing the functional state of the liver, and the morphological profile of the body after a single exposure to a toxic dose of adrenaline were studied. Studies were conducted on 60 adult rats (female) weighing 0.15-0.2 kg, were divided into groups: intact animals; experience - animals, injected with epinephrine hydrochloride intraperitoneally in a dose of 0.5 mg/kg. All kinds of Biological material (blood, liver) were collected out through one and ten days after the start of the experiment. The degree of influence of high doses of epinephrine were evaluated in terms of lipid peroxidation (LPO) and protein (PSP) in liver homogenates, the concentration of average weight molecules (MSM), the activity of ALT, AST, alkaline phosphatase, LDH, total protein concentration, glucose and lactate in the blood plasma, as well as the determination of the prothrombin time (PTT) with the counting on the basis thereof of international normalized ration (INR). Histology of the liver was studied by light microscopy. It was found that throughout the experiment, there was an increased in the concentration of lipid peroxidation products and protein in liver homogenates, there was an increase in the concentration of MSM 1.7. Twenty-four hours after the administration of a toxic dose of adrenaline observed hyperenzymemia that manifested an increase in the activity of ALT and AST, was an increase in LDH. After 10-day five after the start of the experiment established the presence hyperenzymemia activity decreased ALT and AST, LDH activity remained elevated, total protein level was higher than in the group of animal in which investigations were conducted one day after the start of the experiment, PTV also continued to decline. In histological sections of the development of a pathological condition characterized by circulatory disturbance - plasmatization, both in central and in small vessels. From the hepatocytes both in the center and the periphery had changes granular dystrophy type, to some extent vacuolar.

Loads Limits Values of Soils with Petroleum Hydrocarbons

NASA Astrophysics Data System (ADS)

Dumitru, Mihail; Vladimirescu, Andreea

2017-04-01

The high demand for oil and associated products as a source of energy, resulting in increased oil exploitation, producing, refining, transportation, storage, marketing and use led to high levels of environmental pollution. The optimum bioremediation variant proved to be the one in which fertilizer (potassium humate in NPK matrix with microelements and 8% monosaccharides) applied in a 650 l/ha dose was used together with the Zeba absorbent in 32 kg/ha dose, where the TPH level dropped by 58% in 45 days from the pollution with 3% crude oil. Most of these areas are affected by historical pollution. Many organic contaminants may undergo an ongoing process in the soil, whereby over time contaminant become less and less subject to decomposition even though relatively can still be detected in the laboratory analyses. In Romania about 50.000 ha are polluted with oil and/or brine. The bioremediation was the main method of rehabilitation. The Regulation on the assessment of environmental pollution, the following are presented as guide values for total oil hydrocarbons content in soil: - normal: less than 100 mg/kg; - alert values for sensitive soils: 200 mg/kg; - alert values for less sensitive soils: 1000 mg/kg; - intervention values for sensitive soils: 500 mg/kg; - intervention values for less sensitive soils: 2000 mg/kg. Researches done in laboratory monitored the effect of various concentrations of oil (under 2000 mg/kg, 3000 mg/kg, 5000 mg/kg, 7000 mg/kg, 10 000 mg/kg) on germination of wheat seeds at 5 and 7 days after seeding and (fresh and dry) biomass production after 40 days. Tree experiments were done: one with recently contaminated light oil, one with recently contaminated heavy oil and one with old contamination. After 5 days from sowing, the largest number of germinated seeds was found in the experiments with old contamination. The fewest germinated seeds was found in the experience with light oil. The experience with heavy oil showed an intermediate number of emerged plants. In all cases fertilization led to a significant increase of the wheat biomass. After 40 days, the level of total hydrocarbons was reduced on average by 55% in the case of contamination with light oil, by 42% for heavy oil contamination and 12% for old contamination. The BTEX concentration in soil had the lowest values in the experiment with heavy oil contamination, intermediate values in the experiment with historic contamination and higher values within experiment with light oil. We make proposal to change intervention thresholds for sensitive land uses from 500 mg/kg for total oil hydrocarbons to 1000 mg/kg for recently pollution and 2000 mg/kg for old pollution (historical > 5 years). For less sensitive land uses intervention thresholds from 2000 mg/kg of total oil hydrocarbons, values increase to 500 mg/kg for recently pollution and 1000 mg/kg old pollution.

Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bignell, L. J.; Diwan, M. V.; Hans, S.

2015-10-19

Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % andmore » 1.31 ± 0.59 % after ≈ 800 Gy of proton dose, respectively. Some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation.« less

Differential sensitivity of osteoblasts and bacterial pathogens to 405-nm light highlighting potential for decontamination applications in orthopedic surgery

NASA Astrophysics Data System (ADS)

Ramakrishnan, Praveen; Maclean, Michelle; MacGregor, Scott J.; Anderson, John G.; Grant, M. Helen

2014-10-01

Healthcare associated infections pose a major threat to patients admitted to hospitals and infection rates following orthopedic arthroplasty surgery are as high as 4%. A 405-nm high-intensity narrow spectrum light has been proven to reduce environmental contamination in hospital isolation rooms, and there is potential to develop this technology for application in arthroplasty surgery. Cultured rat osteoblasts were exposed to varying light intensities and it was found that exposures of up to a dose of 36 J/cm2 had no significant effect on cell viability [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay], function (alkaline phosphatase activity), and proliferation rate (BrdU cell proliferation assay). High irradiance exposures (54 J/cm2) significantly affected the cell viability indicating that the effects of 405-nm light on osteoblasts are dose dependent. Additionally, exposure of a variety of clinically related bacteria to a dose of 36 J/cm2 resulted in up to 100% kill. These results demonstrating the differential sensitivity of osteoblasts and bacteria to 405-nm light are an essential step toward developing the technique for decontamination in orthopedic surgery.

Maximum dose rate is a determinant of hypothyroidism after 131I therapy of Graves' disease but the total thyroid absorbed dose is not.

PubMed

Krohn, Thomas; Hänscheid, Heribert; Müller, Berthold; Behrendt, Florian F; Heinzel, Alexander; Mottaghy, Felix M; Verburg, Frederik A

2014-11-01

The determinants of successful (131)I therapy of Graves' disease (GD) are unclear. To relate dosimetry parameters to outcome of therapy to identify significant determinants eu- and/or hypothyroidism after (131)I therapy in patients with GD. A retrospective study in which 206 Patients with GD treated in University Hospital between November 1999 and January 2011. All received (131)I therapy aiming at a total absorbed dose to the thyroid of 250 Gy based on pre-therapeutic dosimetry. Post-therapy dosimetric thyroid measurements were performed twice daily until discharge. From these measurements, thyroid (131)I half-life, the total thyroid absorbed dose, and the maximum dose rate after (131)I administration were calculated. In all, 48.5% of patients were hypothyroid and 28.6% of patients were euthyroid after (131)I therapy. In univariate analysis, nonhyperthyroid and hyperthyroid patients only differed by sex. A lower thyroid mass, a higher activity per gram thyroid tissue, a shorter effective thyroidal (131)I half-life, and a higher maximum dose rate, but not the total thyroid absorbed dose, were significantly associated with hypothyroidism. In multivariate analysis, the maximum dose rate remained the only significant determinant of hypothyroidism (P < .001). Maximum dose rates of 2.2 Gy/h and higher were associated with a 100% hypothyroidism rate. Not the total thyroid absorbed dose, but the maximum dose rate is a determinant of successfully achieving hypothyroidism in Graves' disease. Dosimetric concepts aiming at a specific total thyroid absorbed dose will therefore require reconsideration if our data are confirmed prospectively.

Optical cone beam tomography of Cherenkov-mediated signals for fast 3D dosimetry of x-ray photon beams in water.

PubMed

Glaser, Adam K; Andreozzi, Jacqueline M; Zhang, Rongxiao; Pogue, Brian W; Gladstone, David J

2015-07-01

To test the use of a three-dimensional (3D) optical cone beam computed tomography reconstruction algorithm, for estimation of the imparted 3D dose distribution from megavoltage photon beams in a water tank for quality assurance, by imaging the induced Cherenkov-excited fluorescence (CEF). An intensified charge-coupled device coupled to a standard nontelecentric camera lens was used to tomographically acquire two-dimensional (2D) projection images of CEF from a complex multileaf collimator (MLC) shaped 6 MV linear accelerator x-ray photon beam operating at a dose rate of 600 MU/min. The resulting projections were used to reconstruct the 3D CEF light distribution, a potential surrogate of imparted dose, using a Feldkamp-Davis-Kress cone beam back reconstruction algorithm. Finally, the reconstructed light distributions were compared to the expected dose values from one-dimensional diode scans, 2D film measurements, and the 3D distribution generated from the clinical Varian ECLIPSE treatment planning system using a gamma index analysis. A Monte Carlo derived correction was applied to the Cherenkov reconstructions to account for beam hardening artifacts. 3D light volumes were successfully reconstructed over a 400 × 400 × 350 mm(3) volume at a resolution of 1 mm. The Cherenkov reconstructions showed agreement with all comparative methods and were also able to recover both inter- and intra-MLC leaf leakage. Based upon a 3%/3 mm criterion, the experimental Cherenkov light measurements showed an 83%-99% pass fraction depending on the chosen threshold dose. The results from this study demonstrate the use of optical cone beam computed tomography using CEF for the profiling of the imparted dose distribution from large area megavoltage photon beams in water.

Blue-Light Inhibition of Listeria monocytogenes Growth Is Mediated by Reactive Oxygen Species and Is Influenced by σB and the Blue-Light Sensor Lmo0799.

PubMed

O'Donoghue, Beth; NicAogáin, Kerrie; Bennett, Claire; Conneely, Alan; Tiensuu, Teresa; Johansson, Jörgen; O'Byrne, Conor

2016-07-01

Listeria monocytogenes senses blue light via the flavin mononucleotide-containing sensory protein Lmo0799, leading to activation of the general stress response sigma factor SigB (σ(B)). In this study, we investigated the physiological response of this foodborne pathogen to blue light. We show that blue light (460 to 470 nm) doses of 1.5 to 2 mW cm(-2) cause inhibition of growth on agar-based and liquid culture media. The inhibitory effects are dependent on cell density, with reduced effects evident when high cell numbers are present. The addition of 20 mM dimethylthiourea, a scavenger of reactive oxygen species, or catalase to the medium reverses the inhibitory effects of blue light, suggesting that growth inhibition is mediated by the formation of reactive oxygen species. A mutant strain lacking σ(B) (ΔsigB) was found to be less inhibited by blue light than the wild type, likely indicating the energetic cost of deploying the general stress response. When a lethal dose of light (8 mW cm(-2)) was applied to cells, the ΔsigB mutant displayed a marked increase in sensitivity to light compared to the wild type. To investigate the role of the blue-light sensor Lmo0799, mutants were constructed that either had a deletion of the gene (Δlmo0799) or alteration in a conserved cysteine residue at position 56, which is predicted to play a pivotal role in the photocycle of the protein (lmo0799 C56A). Both mutants displayed phenotypes similar to the ΔsigB mutant in the presence of blue light, providing genetic evidence that residue 56 is critical for light sensing in L. monocytogenes Taken together, these results demonstrate that L. monocytogenes is inhibited by blue light in a manner that depends on reactive oxygen species, and they demonstrate clear light-dependent phenotypes associated with σ(B) and the blue-light sensor Lmo0799. Listeria monocytogenes is a bacterial foodborne pathogen that can cause life-threatening infections in humans. It is known to be able to sense and respond to visible light. In this study, we examine the effects of blue light on the growth and survival of this pathogen. We show that growth can be inhibited at comparatively low doses of blue light, and that at higher doses, L. monocytogenes cells are killed. We present evidence suggesting that blue light inhibits this organism by causing the production of reactive oxygen species, such as hydrogen peroxide. We help clarify the mechanism of light sensing by constructing a "blind" version of the blue-light sensor protein. Finally, we show that activation of the general stress response by light has a negative effect on growth, probably because cellular resources are diverted into protective mechanisms rather than growth. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Blue-Light Inhibition of Listeria monocytogenes Growth Is Mediated by Reactive Oxygen Species and Is Influenced by σB and the Blue-Light Sensor Lmo0799

PubMed Central

O'Donoghue, Beth; NicAogáin, Kerrie; Bennett, Claire; Conneely, Alan; Tiensuu, Teresa; Johansson, Jörgen

2016-01-01

ABSTRACT Listeria monocytogenes senses blue light via the flavin mononucleotide-containing sensory protein Lmo0799, leading to activation of the general stress response sigma factor SigB (σB). In this study, we investigated the physiological response of this foodborne pathogen to blue light. We show that blue light (460 to 470 nm) doses of 1.5 to 2 mW cm−2 cause inhibition of growth on agar-based and liquid culture media. The inhibitory effects are dependent on cell density, with reduced effects evident when high cell numbers are present. The addition of 20 mM dimethylthiourea, a scavenger of reactive oxygen species, or catalase to the medium reverses the inhibitory effects of blue light, suggesting that growth inhibition is mediated by the formation of reactive oxygen species. A mutant strain lacking σB (ΔsigB) was found to be less inhibited by blue light than the wild type, likely indicating the energetic cost of deploying the general stress response. When a lethal dose of light (8 mW cm−2) was applied to cells, the ΔsigB mutant displayed a marked increase in sensitivity to light compared to the wild type. To investigate the role of the blue-light sensor Lmo0799, mutants were constructed that either had a deletion of the gene (Δlmo0799) or alteration in a conserved cysteine residue at position 56, which is predicted to play a pivotal role in the photocycle of the protein (lmo0799 C56A). Both mutants displayed phenotypes similar to the ΔsigB mutant in the presence of blue light, providing genetic evidence that residue 56 is critical for light sensing in L. monocytogenes. Taken together, these results demonstrate that L. monocytogenes is inhibited by blue light in a manner that depends on reactive oxygen species, and they demonstrate clear light-dependent phenotypes associated with σB and the blue-light sensor Lmo0799. IMPORTANCE Listeria monocytogenes is a bacterial foodborne pathogen that can cause life-threatening infections in humans. It is known to be able to sense and respond to visible light. In this study, we examine the effects of blue light on the growth and survival of this pathogen. We show that growth can be inhibited at comparatively low doses of blue light, and that at higher doses, L. monocytogenes cells are killed. We present evidence suggesting that blue light inhibits this organism by causing the production of reactive oxygen species, such as hydrogen peroxide. We help clarify the mechanism of light sensing by constructing a “blind” version of the blue-light sensor protein. Finally, we show that activation of the general stress response by light has a negative effect on growth, probably because cellular resources are diverted into protective mechanisms rather than growth. PMID:27129969

Use of a platform in an automated open-field to enhance assessment of anxiety-like behaviors in mice.

PubMed

Pogorelov, Vladimir M; Lanthorn, Thomas H; Savelieva, Katerina V

2007-05-15

The present report describes a setup for simultaneously measuring anxiety-like behaviors and locomotor activity in mice. Animals are placed in a brightly lit, standard automated open-field (OF) in which a rectangular ceramic platform 8 cm high covers one quadrant of the floor. Mice preferred to stay under the platform, avoiding the area with bright illumination. Activities under and outside the platform were measured for 5 min. Chlordiazepoxide and buspirone dose-dependently increased time spent outside the platform (L-Time) and the light distance to total OF distance ratio (L:T-TD) in both genders without changing total OF distance. By contrast, amphetamine decreased L-Time and L:T-TD in males, thus displaying an anxiogenic effect. Imipramine was without selective effect on L-Time or L:T-TD, but decreased total OF distance at the highest dose indicative of a sedative effect. Drug effects were also evaluated in the OF without platform using conventional anxiety measures. Introduction of the platform into the OF apparatus strongly enhanced the sensitivity to anxiolytics. Comparison of strains differing in activity or anxiety levels showed that L-Time and L:T-TD can be used as measures of anxiety-like behavior independent of locomotor activity. Changes in motor activity are reflected in the total distance traveled under and outside the platform. Therefore, the platform test is fully automated, sensitive to both anxiolytic and anxiogenic effects of drugs and genetic phenotypes with little evidence of gender-specific responses, and can be easily utilized by most laboratories measuring behavior.

Specific LED-based red light photo-stimulation procedures improve overall sperm function and reproductive performance of boar ejaculates

PubMed Central

Yeste, Marc; Codony, Francesc; Estrada, Efrén; Lleonart, Miquel; Balasch, Sam; Peña, Alejandro; Bonet, Sergi; Rodríguez-Gil, Joan E.

2016-01-01

The present study evaluated the effects of exposing liquid-stored boar semen to different red light LED regimens on sperm quality and reproductive performance. Of all of the tested photo-stimulation procedures, the best pattern consisted of 10 min light, 10 min rest and 10 min of further light (10-10-10 pattern). This pattern induced an intense and transient increase in the majority of motility parameters, without modifying sperm viability and acrosome integrity. While incubating non-photo-stimulated sperm at 37 °C for 90 min decreased all sperm quality parameters, this reduction was prevented when the previously-described light procedure was applied. This effect was concomitant with an increase in the percentage of sperm with high mitochondrial membrane potential. When sperm were subjected to ‘in vitro’ capacitation, photo-stimulation also increased the percentage of sperm with capacitation-like changes in membrane structure. On the other hand, treating commercial semen doses intended for artificial insemination with the 10-10-10 photo-stimulation pattern significantly increased farrowing rates and the number of both total and live-born piglets for parturition. Therefore, our results indicate that a precise photo-stimulation procedure is able to increase the fertilising ability of boar sperm via a mechanism that could be related to mitochondrial function. PMID:26931070

Combatant Eye Protection: An Introduction to the Blue Light Hazard

DTIC Science & Technology

2015-12-01

visible solar radiation (i.e., blue light ), as well as from light - emitting diode (LED)-generated radiant energy remains a questionable factor under...Garcia, M., Picaud, S., Attia D. 2011. Light - emitting diodes (LED) for domestic lighting : Any risks for the eye?. Progress in retinal and eye research...C., Sliney, D. H., Rollag, M., D., Hanifin, J. P., and Brainard, G. C. 2011. Blue light from light - emitting diodes elicits a dose-dependent

An Efficient, Affordable Optically Stimulated Luminescent (OSL) Annealer.

PubMed

Abraham, Sara A; Frank, Samuel J; Kearfott, Kimberlee J

2017-07-01

Optically stimulated luminescent (OSL) dosimeters are devices used for measuring doses of ionizing radiation. Signal is stored within an OSL material so that when stimulated with light, light of a specific wavelength is emitted in proportion to the integrated ionizing radiation dose. Each interrogation of the material results in the loss of a small fraction of signal, thus allowing multiple interrogations leading to more accurate measurements of dose. In order to reuse a dosimeter, the residual signals from prior doses must be taken into account and subtracted from current readings, adding uncertainty to any future measurements. To reduce these errors when they become large, it is desirable to completely clear the stored signal or anneal the dosimeter. Traditionally, heating the material has accomplished this. In a commercially available dosimeter badge system, the OSL material Al2O3:C is incorporated into a plastic slide that would melt at the necessary high temperatures, which can reach 900 °C, required for annealing. Fortunately, due to the material's high sensitivity to light, OSLs can be optically annealed instead. In order to do this, an affordable OSL dosimeter annealer was designed with inexpensive, exchangeable blue, green, and white high intensity light-emitting diodes (LEDs). Several dosimeters were repeatedly annealed for recorded intervals and then read out. A single dosimeter was partially annealed through repeated interrogations with the LED array from a commercial reader. The signal loss due to the exposure to each light was analyzed to determine the practicality and efficiency of each color. The rate and extent of signal loss was dependent not only on the spectrum of annealing light but on the initial signal levels as well. These findings suggest that blue LEDs are the most promising for effective and rapid clearing of the OSL material Al2O3:C.

The effect of light:dark cycles of medium frequency on photosynthesis by Chlorella vulgaris and the implications for waste stabilisation pond design and performance.

PubMed

Ratchford, I A J; Fallowfield, H J

2003-01-01

The effect of light/dark (L:D) cycle times on the recovery from photoinhibition of green micro-alga Chlorella vulgaris (CCAP211/11c) and the cyanobacterium Synechococcus (CCAP1479/5) was investigated using an irradiated, temperature controlled oxygen electrode. The onset of photoinhibition in both organisms occurred at irradiances > 300 micromol m(-2)s(-1) at temperatures >15 degrees C. Light/dark cycle times were controlled independently using a relay timer and shutter placed between the quartz iodide light source and the oxygen electrode chamber. Oxygen evolution decreased rapidly when cells were continuously irradiated at 300, 500 and 750 micromol m(-2)s(-1). However, Chlorella cells irradiated at 300, 500 and 750 micromol m(-2)s(-1)on a L:D cycle of 60s:20s, 30s:60s and 60s: 120s respectively, maintained a constant rate of oxygen evolution over a 24 h incubation period. Exposure time to a given incident irradiance rather than the total light dose received appeared to determine the effect of light/dark cycle times on photosynthesis. A relationship was established between L:D ratio required to maintain constant oxygen production and incident photon flux density. The results suggest that the adverse effects of high irradiances on algae near the surface of a stratified waste stabilisation pond might be ameliorated by controlled mixing of algal cells through the depth of the pond.

Total body irradiation, toward optimal individual delivery: dose evaluation with metal oxide field effect transistors, thermoluminescence detectors, and a treatment planning system.

PubMed

Bloemen-van Gurp, Esther J; Mijnheer, Ben J; Verschueren, Tom A M; Lambin, Philippe

2007-11-15

To predict the three-dimensional dose distribution of our total body irradiation technique, using a commercial treatment planning system (TPS). In vivo dosimetry, using metal oxide field effect transistors (MOSFETs) and thermoluminescence detectors (TLDs), was used to verify the calculated dose distributions. A total body computed tomography scan was performed and loaded into our TPS, and a three-dimensional-dose distribution was generated. In vivo dosimetry was performed at five locations on the patient. Entrance and exit dose values were converted to midline doses using conversion factors, previously determined with phantom measurements. The TPS-predicted dose values were compared with the MOSFET and TLD in vivo dose values. The MOSFET and TLD dose values agreed within 3.0% and the MOSFET and TPS data within 0.5%. The convolution algorithm of the TPS, which is routinely applied in the clinic, overestimated the dose in the lung region. Using a superposition algorithm reduced the calculated lung dose by approximately 3%. The dose inhomogeneity, as predicted by the TPS, can be reduced using a simple intensity-modulated radiotherapy technique. The use of a TPS to calculate the dose distributions in individual patients during total body irradiation is strongly recommended. Using a TPS gives good insight of the over- and underdosage in a patient and the influence of patient positioning on dose homogeneity. MOSFETs are suitable for in vivo dosimetry purposes during total body irradiation, when using appropriate conversion factors. The MOSFET, TLD, and TPS results agreed within acceptable margins.

Control of burn wound sepsis in rats by methylene blue-mediated photodynamic treatment

NASA Astrophysics Data System (ADS)

Hasegawa, Hiroyuki; Sato, Shunichi; Kawauchi, Satoko; Saitoh, Daizoh; Shinomiya, Nariyoshi; Ashida, Hiroshi; Terakawa, Mitsuhiro

2012-02-01

Control of wound sepsis is an important challenge in traumatology. However, increase in the drug-resistant bacteria makes this challenge considerably difficult in recent years. In this study, we attempted to control burn wound sepsis in rats by photodynamic treatment, which has been reported to be effective against some drug-resistant bacteria. A 20% TBSA (total body surface area) full-thickness burn was made in rat dorsal skin, and five days after injury, a suspension of P. aeruginosa was applied to the wound surface. At 30 min after infection, a methylene blue (MB) solution was applied to the wound surface; 5 min afterwards, the wound was illuminated with a 665-nm light emitting diode (LED) array for 10 min. This treatment (application of MB and illumination) was repeated 3 times successively. The averaged light intensity on the wound surface was 3.3 mW/cm2, the corresponding total light dose being 5.9 J/cm2. One week after injury, the numbers of bacteria in the blood and liver were counted by colony forming assay. In the liver, the number of bacteria of the treated group was significantly lower than that of the sham control group without photodynamic treatment. In the blood, no bacteria were detected in the treated group, while a certain amount of bacteria was detected in the control group. These results demonstrate the efficacy of MB-mediated PDT with a red LED array to control burn wound sepsis.

Comparison between in vivo dosimetry and barium contrast technique for prediction of rectal complications in high-dose-rate intracavitary radiotherapy in cervix cancer patients.

PubMed

Huh, Seung Jae; Lim, Do Hoon; Ahn, Yong Chan; Lee, Jeong Eun; Kang, Min Kyu; Shin, Seong Soo; Shin, Kyung Hwan; Kim, Bokyung; Park, Won; Han, Youngyih

2003-03-01

To investigate the correlation between late rectal complications and rectal dose in cervix cancer patients treated with high-dose-rate intracavitary radiotherapy (HDR ICR) and to analyze factors reducing rectal complications. A total of 136 patients with cervix cancer who were treated with external beam radiotherapy (EBRT) and HDR ICR from 1995 to 1999 were retrospectively analyzed. Radiotherapy (RT) consisted of EBRT plus HDR ICR. The median EBRT dose was 50.4 Gy, and midline block was done after 30-50 Gy of EBRT. A total of six fractions of HDR ICR with 4 Gy fraction size each were applied twice per week to the A point. The rectal dose was calculated at the rectal reference point using the barium contrast criteria. In vivo measurement of the rectal dose was performed with thermoluminescent dosimeter (TLD) during HDR ICR. The median follow-up period was 26 months (range 6-60 months). A total of 16 patients (12%) experienced rectal bleeding, which occurred 4-33 months (median 11 months) after the completion of RT. The calculated rectal doses did not differ in patients with rectal bleeding and those without, but the measured rectal doses were higher in affected patients. The differences of the measured ICR fractional rectal dose, ICR total rectal dose, and total rectal biologically equivalent dose (BED) were statistically significant. When the measured ICR total rectal dose exceeded 16 Gy, the ratio of the measured rectal dose to A point dose was > 70%; when the measured rectal BED exceeded 110 Gy(3), a high possibility of late rectal complications could be found. In vivo dosimetry using TLD during HDR ICR was a good predictor of late rectal complications. Hence, if data from in vivo dosimetry shows any possibility of rectal bleeding, efforts should be made to reduce the rectal dose.

Evident cognitive impairments in seemingly recovered patients after midazolam-based light sedation during diagnostic endoscopy.

PubMed

Hsu, Yen-Hsuan; Lin, Feng-Sheng; Yang, Chi-Cheng; Lin, Chih-Peng; Hua, Mau-Sun; Sun, Wei-Zen

2015-06-01

Midazolam is a widely used sedative agent during colonoscopy, with cognitive toxicity. However, the potential cognitive hazard of midazolam-based light sedation has not been sufficiently examined. We aimed to examine the cognitive safety and vulnerability profile under midazolam light sedation, with a particular focus on individual variations. We conducted a prospective case-controlled study in an academic hospital. In total, 30 patients undergoing sedative colonoscopy as part of a health check-up were recruited. Neuropsychological testing on the full cognitive spectrum was evaluated at 15 minutes and 120 minutes after low-dose midazolam administration. The modified reliable change index (RCI) was used for intrapersonal comparisons and controlling for practice effects. Midazolam affected psychomotor speed (48%), memory (40%), learning (32%), working memory (17%), and sustained attention (11%), while sparing orientation and the fluency aspect of executive function at the acute stage. Residual memory (10%) and learning (10%) impairments at 2 hours after administration were evidenced in some patients. The three object recall and digit symbol coding tests can serve as useful screening tools. Midazolam-based light sedation induced selective cognitive impairments and prolonged cognitive impairments occurred in patients with advanced age. A longer observation time and further screening were recommended for patients due to their at risk state. Copyright © 2013. Published by Elsevier B.V.

Total Dose Survivability of Hubble Electronic Components

NASA Technical Reports Server (NTRS)

Xapsos, M. A.; Stauffer, C.; Jordan, T.; Poivey, C.; Haskins, D. N.; Lum, G.; Pergosky, A. M.; Smith, D. C.; LaBel, K. A.

2017-01-01

A total dose analysis for exposure of electronic parts at the box level is presented for the Hubble Space Telescope. This was done using solid angle sectoring/3-dimensional ray trace and Monte Carlo radiation transport simulations. Results are discussed in terms of parts that are potential total dose concerns.

New Approach to Total Dose Specification for Spacecraft Electronics

NASA Technical Reports Server (NTRS)

Xapsos, Michael

2017-01-01

Variability of the space radiation environment is investigated with regard to total dose specification for spacecraft electronics. It is shown to have a significant impact. A new approach is developed for total dose requirements that replaces the radiation design margin concept with failure probability during a mission.

LTC1877 High Efficiency Regulator Total Ionizing Dose Test Report

NASA Technical Reports Server (NTRS)

Oldham, Timothy; Pellish, Jonathan; Boutte, Alvin

2012-01-01

This report presents total ionizing dose evaluation data for the Linear Technology Corporation LTC1877 high efficiency monolithic synchronous step-down regulator. Data sheet parameters were tracked as a function of ionizing dose up to a total of 20 krad(SiO2). Control devices were also used.

Impact of Thiamethoxam on Honey Bee Queen (Apis mellifera carnica) Reproductive Morphology and Physiology.

PubMed

Gajger, Ivana Tlak; Sakač, Martina; Gregorc, Aleš

2017-09-01

High honey bee losses around the world have been linked in part by the regular use of neonicotinoids in agriculture. In light of the current situation, the aim of this study was to investigate the effects of thiamethoxam on the development of the reproductive system and physiology in the honey bee queen. Two experimental groups of honey bee queen larvae were treated with thiamethoxam during artificial rearing, applied via artificial feed in two cycles. In the first rearing cycle, honey bee larvae received a single treatment dose (4.28 ng thiamethoxam/queen larva on the 4th day after larvae grafting in artificial queen cells), while the second honey bee queen rearing cycle received a double treatment dose (total of 8.56 ng thiamethoxam/queen larva on the 4th and 5th day after larvae grafting in artificial queen cells). After emerging, queens were anesthetized and weighed, and after mating with drones were anesthetized, weighed, and sectioned. Ovary mass and number of stored sperm were determined. Body weight differed between untreated and treated honey bee queens. The results also show a decrease in the number of sperm within honey bee queen spermathecae that received the double thiamethoxam dose.

Effects of histidine and n-acetylcysteine on experimental lesions induced by doxorubicin in sciatic nerve of rats.

PubMed

Farshid, Amir Abbas; Tamaddonfard, Esmaeal; Najafi, Sima

2015-10-01

In this study, the effect of separate and combined intraperitoneal (i.p.) injections of histidine and n-acetylcysteine were investigated on experimental damage induced by doxorubicin (DOX) in sciatic nerve of rats. DOX was i.p. injected at a dose of 4 mg/kg once weekly for four weeks. Histidine and n-acetylcysteine were i.p. injected at a same dose of 20 mg/kg. Cold and mechanical allodynia were recorded using acetone spray and von Frey filaments tests, respectively. The sciatic nerve damage was evaluated by light microscopy. Plasma levels of malondialdehyde (MDA) and total antioxidant capacity (TAC) were measured. Histidine and especially n-acetylcysteine at a same dose of 20 mg/kg suppressed cold and mechanical allodynia, improved sciatic nerve lesions and reversed MDA and TAC levels in DOX-treated groups. Combination treatment with histidine and n-acetylcysteine showed better responses when compared with them used alone. The results of the present study showed peripheral neuroprotective effects for histidine and n-acetylcysteine. Reduction of free radical-induced toxic effects may have a role in neuroprotective properties of histidine and n-acetylcysteine.

Effects of 810 nm laser on mouse primary cortical neurons

NASA Astrophysics Data System (ADS)

Kharkwal, Gitika B.; Sharma, Sulbha K.; Huang, Ying-Ying; De Taboada, Luis; McCarthy, Thomas; Hamblin, Michael R.

2011-03-01

In the past four decades numerous studies have reported the efficacy of low level light (laser) therapy (LLLT) as a treatment for diverse diseases and injuries. Recent studies have shown that LLLT can biomodulate processes in the central nervous system and has been extensively studied as a stroke treatment. However there is still a lack of knowledge on the effects of LLLT at the cellular level in neurons. The present study aimed to study the effect of 810 nm laser on several cellular processes in primary cortical neurons cultured from mouse embryonic brains. Neurons were irradiated with light dose of 0.03, 0.3, 3, 10 and 30 J/cm2 and intracellular levels of reactive oxygen species, nitric oxide and calcium were measured. The changes in mitochondrial function in response to light were studied in terms of adenosine triphosphate (ATP) and mitochondrial membrane potential (MMP). Light induced a significant increase in calcium, ATP and MMP at lower fluences and a decrease at higher fluence. ROS was induced significantly by light at all light doses. Nitric oxide levels also showed an increase on treatment with light. The results of the present study suggest that LLLT at lower fluences is capable of inducing mediators of cell signaling process which in turn may be responsible for the biomodulatory effects of the low level laser. At higher fluences beneficial mediators are reduced but potentially harmful mediators are increased thus offering an explanation for the biphasic dose response.

Novel, full 3D scintillation dosimetry using a static plenoptic camera.

PubMed

Goulet, Mathieu; Rilling, Madison; Gingras, Luc; Beddar, Sam; Beaulieu, Luc; Archambault, Louis

2014-08-01

Patient-specific quality assurance (QA) of dynamic radiotherapy delivery would gain from being performed using a 3D dosimeter. However, 3D dosimeters, such as gels, have many disadvantages limiting to quality assurance, such as tedious read-out procedures and poor reproducibility. The purpose of this work is to develop and validate a novel type of high resolution 3D dosimeter based on the real-time light acquisition of a plastic scintillator volume using a plenoptic camera. This dosimeter would allow for the QA of dynamic radiation therapy techniques such as intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT). A Raytrix R5 plenoptic camera was used to image a 10 × 10 × 10 cm(3) EJ-260 plastic scintillator embedded inside an acrylic phantom at a rate of one acquisition per second. The scintillator volume was irradiated with both an IMRT and VMAT treatment plan on a Clinac iX linear accelerator. The 3D light distribution emitted by the scintillator volume was reconstructed at a 2 mm resolution in all dimensions by back-projecting the light collected by each pixel of the light-field camera using an iterative reconstruction algorithm. The latter was constrained by a beam's eye view projection of the incident dose acquired using the portal imager integrated with the linac and by physical consideration of the dose behavior as a function of depth in the phantom. The absolute dose difference between the reconstructed 3D dose and the expected dose calculated using the treatment planning software Pinnacle(3) was on average below 1.5% of the maximum dose for both integrated IMRT and VMAT deliveries, and below 3% for each individual IMRT incidences. Dose agreement between the reconstructed 3D dose and a radiochromic film acquisition in the same experimental phantom was on average within 2.1% and 1.2% of the maximum recorded dose for the IMRT and VMAT delivery, respectively. Using plenoptic camera technology, the authors were able to perform millimeter resolution, water-equivalent dosimetry of an IMRT and VMAT plan over a whole 3D volume. Since no moving parts are required in the dosimeter, the incident dose distribution can be acquired as a function of time, thus enabling the validation of static and dynamic radiation delivery with photons, electrons, and heavier ions.

Novel, full 3D scintillation dosimetry using a static plenoptic camera

PubMed Central

Goulet, Mathieu; Rilling, Madison; Gingras, Luc; Beddar, Sam; Beaulieu, Luc; Archambault, Louis

2014-01-01

Purpose: Patient-specific quality assurance (QA) of dynamic radiotherapy delivery would gain from being performed using a 3D dosimeter. However, 3D dosimeters, such as gels, have many disadvantages limiting to quality assurance, such as tedious read-out procedures and poor reproducibility. The purpose of this work is to develop and validate a novel type of high resolution 3D dosimeter based on the real-time light acquisition of a plastic scintillator volume using a plenoptic camera. This dosimeter would allow for the QA of dynamic radiation therapy techniques such as intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT). Methods: A Raytrix R5 plenoptic camera was used to image a 10 × 10 × 10 cm3 EJ-260 plastic scintillator embedded inside an acrylic phantom at a rate of one acquisition per second. The scintillator volume was irradiated with both an IMRT and VMAT treatment plan on a Clinac iX linear accelerator. The 3D light distribution emitted by the scintillator volume was reconstructed at a 2 mm resolution in all dimensions by back-projecting the light collected by each pixel of the light-field camera using an iterative reconstruction algorithm. The latter was constrained by a beam's eye view projection of the incident dose acquired using the portal imager integrated with the linac and by physical consideration of the dose behavior as a function of depth in the phantom. Results: The absolute dose difference between the reconstructed 3D dose and the expected dose calculated using the treatment planning software Pinnacle3 was on average below 1.5% of the maximum dose for both integrated IMRT and VMAT deliveries, and below 3% for each individual IMRT incidences. Dose agreement between the reconstructed 3D dose and a radiochromic film acquisition in the same experimental phantom was on average within 2.1% and 1.2% of the maximum recorded dose for the IMRT and VMAT delivery, respectively. Conclusions: Using plenoptic camera technology, the authors were able to perform millimeter resolution, water-equivalent dosimetry of an IMRT and VMAT plan over a whole 3D volume. Since no moving parts are required in the dosimeter, the incident dose distribution can be acquired as a function of time, thus enabling the validation of static and dynamic radiation delivery with photons, electrons, and heavier ions. PMID:25086549

Total dose bias dependency and ELDRS effects in bipolar linear devices

NASA Technical Reports Server (NTRS)

Yui, C. C.; McClure, S. S.; Rex, B. G.; Lehman, J. M.; Minto, T. D.; Wiedeman, M.

2002-01-01

Total dose tests of several bipolar linear devices show sensitivity to both dose rate and bias during exposure. All devices exhibited Enhanced Low Dose Rate Sensitivity (ELDRS). An accelerated ELDRS test method for three different devices demonstrate results similar to tests at low dose rate. Behavior and critical parameters from these tests are compared and discussed.

Assessment of radiation doses from residential smoke detectors that contain americium-241

NASA Astrophysics Data System (ADS)

Odonnell, F. R.; Etnier, E. L.; Holton, G. A.; Travis, C. C.

1981-10-01

External dose equivalents and internal dose commitments were estimated for individuals and populations from annual distribution, use, and disposal of 10 million ionization chamber smoke detectors that contain 110 kBq americium-241 each. Under exposure scenarios developed for normal distribution, use, and disposal using the best available information, annual external dose equivalents to average individuals were estimated to range from 4 fSv to 20 nSv for total body and from 7 fSv to 40 nSv for bone. Internal dose commitments to individuals under post disposal scenarios were estimated to range from 0.006 to 80 micro-Sv (0.0006 to 8 mrem) to total body and from 0.06 to 800 micro-Sv to bone. The total collective dose (the sum of external dose equivalents and 50-year internal dose commitments) for all individuals involved with distribution, use, or disposal of 10 million smoke detectors was estimated to be about 0.38 person-Sv (38 person-rem) to total body and 00 ft squared.

Photochemical eradication of methicillin-resistant Staphylococcus aureus by blue light activation of riboflavin.

PubMed

Makdoumi, Karim; Goodrich, Ray; Bäckman, Anders

2017-08-01

To compare elimination of methicillin-resistant Staphylococcus aureus (MRSA) by exposure of blue light alone and with riboflavin. A reference strain of MRSA was cultured and diluted in PBS with and without riboflavin (0.01%). Fifteen microlitre was added on a microscope slide, creating a fluid layer with a thickness of around 400 microns. Both of the bacterial suspensions were exposed to blue light, and the effect between exposure with and without riboflavin was compared. Evaluation involved two different wavelengths (412 and 450 nm) of blue light with a lower (5.4 J/cm 2 ) and higher dose (approximately 28.5 J/cm 2 ). The effect of 412 nm light was also evaluated for a thicker fluid layer (1.17 mm). After exposure, colony-forming units (CFUs) were determined for each solution. All measurements were repeated eight times. The reductions in bacteria were similar for both wavelengths. With riboflavin, a statistically significant elimination was observed for both 412 and 450 nm (p < 0.001). At both dosages, the mean reduction was more pronounced with the presence of riboflavin than without it. Using the higher dose, CFU reduction was 99% and 98%, respectively, for 412 and 450 nm light. The bactericidal efficacy was high also in the deeper fluid layer (93%, higher dose). Riboflavin enhanced the antibacterial effect on the exposed MRSA strain of blue light for both 412 and 450 nm blue light. This indicates that blue light could be considered for possible implementation in deep corneal infections. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Dose-dependent collagen cross-linking of rabbit scleral tissue by blue light and riboflavin treatment probed by dynamic shear rheology.

PubMed

Schuldt, Carsten; Karl, Anett; Körber, Nicole; Koch, Christian; Liu, Qing; Fritsch, Anatol W; Reichenbach, Andreas; Wiedemann, Peter; Käs, Josef A; Francke, Mike; Iseli, Hans Peter

2015-08-01

To determine the visco-elastic properties of isolated rabbit scleral tissue and dose-dependent biomechanical and morphological changes after collagen cross-linking by riboflavin/blue light treatment. Scleral patches from 87 adult albino rabbit eyes were examined by dynamic shear rheology. Scleral patches were treated by riboflavin and different intensities of blue light (450 nm), and the impact on the visco-elastic properties was determined by various rheological test regimes. The relative elastic modulus was calculated from non-treated and corresponding treated scleral patches, and treatments with different blue light intensities were compared. Shear rheology enables us to study the material properties of scleral tissue within physiological relevant parameters. Cross-linking treatment increased the viscous as well as the elastic modulus and changed the ratio of the elastic versus viscous proportion in scleral tissue. Constant riboflavin application combined with different blue light intensities from 12 mW/cm(2) up to 100 mW/cm(2) increased the relative elastic modulus of scleral tissue by factors up to 1.8. Further enhancement of the applied light intensity caused a decline of the relative elastic modulus. This might be due to destructive changes of the collagen bundle structure at larger light intensities, as observed by histological examination. Collagen cross-linking by riboflavin/blue light application increases the biomechanical stiffness of the sclera in a dose-dependent manner up to certain light intensities. Therefore, this treatment might be a suitable therapeutic approach to stabilize the biomechanical properties of scleral tissue in cases of pathological eye expansion. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

The repair of low dose UV light-induced damage to human skin DNA in condition of trace amount Mg 2+

NASA Astrophysics Data System (ADS)

Gao, Fang; Guo, Zhouyi; Zheng, Changchun; Wang, Rui; Liu, Zhiming; Meng, Pei; Zhai, Juan

2008-12-01

Ultraviolet light-induced damage to human skin DNA was widely investigated. The primary mechanism of this damage contributed to form cyclobutane pyrimidine dimmers (CPDs). Although the distribution of UV light-induced CPDs within a defined sequence is similar, the damage in cellular environment which shields the nuclear DNA was higher than that in organism in apparent dose. So we use low UVB light as main study agent. Low dose UV-irradiated HDF-a cells (Human Dermal Fibroblasts-adult cells) which is weaker than epidermic cells were cultured with DMEM at different trace amount of Mg2+ (0mmol/L , 0.1mmol/L , 0.2mmol/L, 0.4mmol/L, 0.8mmol/L, 1.2mmol/L) free-serum DMEM and the repair of DNA strands injured were observed. Treat these cells with DNA strand breaks detection, photoproducts detection and the repair of photoproducts detection. Then quantitate the role of trace amount Mg2+ in repair of UV light-induced damage to human skin. The experiment results indicated that epidermic cells have capability of resistance to UV-radiation at a certain extent. And Mg2+ can regulate the UV-induced damage repair and relative vitality. It can offer a rationale and experiment data to relieve UV light-induced skin disease.

Effect of upright tilt on ventricular/vascular coupling in chronically instrumented primates

NASA Technical Reports Server (NTRS)

Tran, C. C.; Latham, R. D.; Self, D. A.; Fanton, J. W.; White, C. D.; Owens, R. W.

1993-01-01

Studies of the hydraulic loading conditions on the heart in humans, especially pulsatile load, have primarily been limited to the supine state. Therefore, we have chosen a nonhuman primate model, the baboon, to assess left ventricular/vascular coupling in both supine and upright positions. Primate subjects were studied by catheterization under sedation and then after surgical implantation of transducers. This allowed the evaluation of postural stress in the chronically instrumented conscious baboon and then after light dissociative doses of ketamine. Basic hemodynamic variables were evaluated for baboons in supine and upright positions. Fourier analysis was applied to aortic pressure and flow to obtain input and characteristic impedance and the ratio of pulsatile (Wp) to total (Wt) left ventricular power (Wp/Wt). The aortic reflected, or backward, pressure was also calculated. Peripheral resistance increased (P = 0.01) and reflected pressure decreased (17.74 +/- 1.50 vs. 15.21 +/- 2 mmHg; P < 0.01) in upright subjects. Characteristic impedance and Wp/Wt were unchanged. Postoperatively, peripheral resistance increased (2,651 +/- 311 vs. 3,667 +/- 276; P < 0.05) and mean power and Wt decreased (P < 0.01) without changes in reflected pressure. All variables were unchanged after light dissociative doses of ketamine. Thus there is no significant change in efficiency of left ventricular/vascular coupling formulated in terms of Wp/Wt or input impedance with postural stress.

EXACT DOSE X-IRRADIATION OF VARIOUS REGIONS OF THE HEAD AND VISUAL SENSATIONS--X-RAY LOCATION METHOD OF STUDY OF THE REACTIVITY OF THE CENTRAL NERVOUS SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gurtovoi, G.K.; Burdianskaya, E.O.

1960-01-01

The primary substrate excited by threshold doses of x radiation of the normal human eye causes perception of a light flash in the retinal region. The threshold dose for the retina is about 1 mr; the threshold absorbed dose is about 1 mrad. Persons with a removed eyeball, on irradiation of the operated region with a frontal x-ray beam, perceive a flash of light at definite doses of radiation. Six persons taking part in an experiment saw a flash at doses of 17 to 150 mr (different observers saw flash at different doses) and did not see flash at dosesmore » of 5 to 90 mr. The cause of x-ray phosphene on frontal irradiation of the region of the removed eye with threshold doses is neither the reactivity of the optic nerve stump, the reactivity of the parts of the brain irradiated, nor the sensitivity of the skin receptors. In the cases considered, the cause of x-ray phosphene was irradiation of the retina of the nomnal eye by scattered x rays. The averaged coefficient of scatter was about 2%. On irradiation of the occiptal regions of the brain in subjects with normal eyes at a dose of about 150 mr, one subject perceived a flash of light. In this case, the absorbed dose for the occipital regions of the brain was about 40 mrad. The reason for this phenomenon must be explored. Stimulation of the cerebral formations (after atrophic changes in the visual tract and cortex) by x radia tion with a dose of up to 3 r, did not cause visual sensations. With the disposition of the beam, the absorbed dose for the chiasma was about 1 rad and for the occipital regions about 0.2 rad. In the study of threshold visual sensation and their causes on x irradiation of various regions of the head, it is important to apply defined doses of radiation. Scatter of the x rays in the head must be taken into consideration. (auth)« less

Characterization of the guinea pig animal model and subsequent comparison of the behavioral effects of selective dopaminergic drugs and methamphetamine

PubMed Central

Lee, Kiera-Nicole; Pellom, Samuel T.; Oliver, Ericka; Chirwa, Sanika

2014-01-01

Though not commonly used in behavior tests guinea pigs may offer subtle behavior repertoires that better mimic human activity and warrant study. To test this, 31 Hartley guinea pigs (male, 200–250 g) were evaluated in PhenoTyper cages using the video-tracking EthoVision XT 7.0 software. Results showed that guinea pigs spent more time in the hidden zone (small box in corner of cage) than the food/water zone, or arena zone. Guinea pigs exhibited thigmotaxis (a wall following strategy) and were active throughout the light and dark phases. Eating and drinking occurred throughout the light and dark phases. An injection of 0.25 mg/kg SCH23390, the dopamine D1 receptors (D1R) antagonist, produced significant decreases in time spent in the hidden zone. There were insignificant changes in time spent in the hidden zone for guinea pigs treated with 7.5 mg SKF38393 (D1R agonist), 1.0 mg/kg sulpiride (D2R antagonist), and 1.0 or 10.0 mg/kg methamphetamine. Locomotor activity profiles were unchanged after injections of saline, SKF38393, SCH23390 and sulpiride. By contrast, a single injection or repeated administration for 7 days of low-dose methamphetamine induced transient hyperactivity but this declined to baseline levels over the 22-hour observation period. Guinea pigs treated with high-dose methamphetamine displayed sustained hyperactivity and travelled significantly greater distances over the circadian cycle. Subsequent 7-day treatment with high-dose methamphetamine induced motor sensitization and significant increases in total distances moved relative to single drug injections or saline controls. These results highlight the versatility and unique features of the guinea pig for studying brain-behavior interactions. PMID:24436154

Low-dose topical 5-aminolevulinic acid photodynamic therapy in the treatment of different severity of acne vulgaris.

PubMed

Ma, Li; Xiang, Lei-Hong; Yu, Bo; Yin, Rui; Chen, Lei; Wu, Yan; Tan, Zhi-Jian; Liu, Yong-Bin; Tian, Hong-Qing; Li, Hui-Zhong; Lin, Tong; Wang, Xiu-Li; Li, Yuan-Hong; Wang, Wei-Zheng; Yang, Hui-Lan; Lai, Wei

2013-12-01

To investigate the efficacy and safety of low-concentration 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in the treatment of different severity of acne vulgaris and optimize the treatment regimen. A self-controlled multicenter clinical trial was carried out in 15 centers throughout China. A total of 397 acne patients of grade II-IV received 3- or 4-session PDT treatment. 5% ALA gel was applied topically to acne lesions for 1h incubation. The lesions were irradiated by a LED light of 633 nm at dose levels of 96-120 J/cm(2). Clinical assessment was conducted before and after every treatment up to 8 weeks. The effective rate overall and of grade II, III and IV are 82.1%, 71.6%, 79.6% and 88.2%, respectively. The effective rate rises significantly proportionally to the severity of acne (P<0.01). No significant differences are found in the efficacy between patients received 3-session and 4-session PDT treatments (P>0.05). The count of inflammatory and non-inflammatory acne lesions gradually decrease after each treatment (P<0.01) and during the 8-week follow up (P<0.01 or P<0.05). Maximum efficacy is obtained at 8 weeks after the treatment completion. A low-dose topical ALA-PDT regimen using 5% ALA, 1h incubation and red light source of 3 treatment sessions is suggested as optimal scheme for the treatment of different severity of acne vulgaris in Chinese patients. Superior efficacy is found in severe cystic acne of grade IV with mild side effects. Copyright © 2013 Elsevier B.V. All rights reserved.

Interactive lethal and mutagenic effects of ultraviolet light and bleomycin in yeast: synergism or antagonism?

PubMed

Lillo, O L; Severgnini, A A; Nunes, E M

1997-11-01

The mutagenic interactions of ultraviolet light and bleomycin in haploid populations of Saccharomyces cerevisiae were analyzed. Survival and mutation frequency as a function of different bleomycin concentrations after one conditioning dose of UV radiation were determined. Furthermore, corresponding interaction functions and sensitization factors were calculated. A synergistic interaction between UV light and bleomycin was shown for both lethal and mutagenic events when the cells were in nutrient broth during the treatments. Conversely, the interaction between UV light and bleomycin was antagonistic when the cells were in deionized water during the treatment. The magnitude of lethal and mutagenic interactions depends on dose, and thus presumably on the number of lesions. The observed interactions between UV light and bleomycin suggest that the mechanism that is most likely involved is the induction of repair systems with different error probabilities during the delay of cell division.

Joint minimization of uplink and downlink whole-body exposure dose in indoor wireless networks.

PubMed

Plets, D; Joseph, W; Vanhecke, K; Vermeeren, G; Wiart, J; Aerts, S; Varsier, N; Martens, L

2015-01-01

The total whole-body exposure dose in indoor wireless networks is minimized. For the first time, indoor wireless networks are designed and simulated for a minimal exposure dose, where both uplink and downlink are considered. The impact of the minimization is numerically assessed for four scenarios: two WiFi configurations with different throughputs, a Universal Mobile Telecommunications System (UMTS) configuration for phone call traffic, and a Long-Term Evolution (LTE) configuration with a high data rate. Also, the influence of the uplink usage on the total absorbed dose is characterized. Downlink dose reductions of at least 75% are observed when adding more base stations with a lower transmit power. Total dose reductions decrease with increasing uplink usage for WiFi due to the lack of uplink power control but are maintained for LTE and UMTS. Uplink doses become dominant over downlink doses for usages of only a few seconds for WiFi. For UMTS and LTE, an almost continuous uplink usage is required to have a significant effect on the total dose, thanks to the power control mechanism.

Joint Minimization of Uplink and Downlink Whole-Body Exposure Dose in Indoor Wireless Networks

PubMed Central

Plets, D.; Joseph, W.; Vanhecke, K.; Vermeeren, G.; Wiart, J.; Aerts, S.; Varsier, N.; Martens, L.

2015-01-01

The total whole-body exposure dose in indoor wireless networks is minimized. For the first time, indoor wireless networks are designed and simulated for a minimal exposure dose, where both uplink and downlink are considered. The impact of the minimization is numerically assessed for four scenarios: two WiFi configurations with different throughputs, a Universal Mobile Telecommunications System (UMTS) configuration for phone call traffic, and a Long-Term Evolution (LTE) configuration with a high data rate. Also, the influence of the uplink usage on the total absorbed dose is characterized. Downlink dose reductions of at least 75% are observed when adding more base stations with a lower transmit power. Total dose reductions decrease with increasing uplink usage for WiFi due to the lack of uplink power control but are maintained for LTE and UMTS. Uplink doses become dominant over downlink doses for usages of only a few seconds for WiFi. For UMTS and LTE, an almost continuous uplink usage is required to have a significant effect on the total dose, thanks to the power control mechanism. PMID:25793213

The in vitro photodynamic effect of laser activated gallium, indium and iron phthalocyanine chlorides on human lung adenocarcinoma cells.

PubMed

Maduray, K; Odhav, B

2013-11-05

Metal-based phthalocyanines currently are utilized as a colorant for industrial applications but their unique properties also make them prospective photosensitizers. Photosensitizers are non-toxic drugs, which are commonly used in photodynamic therapy (PDT), for the treatment of various cancers. PDT is based on the principle that, exposure to light shortly after photosensitizer administration predominately leads to the production of reactive oxygen species for the eradication of cancerous cells and tissue. This in vitro study investigated the photodynamic effect of gallium (GaPcCl), indium (InPcCl) and iron (FePcCl) phthalocyanine chlorides on human lung adenocarcinoma cells (A549). Experimentally, 2 × 10(4)cells/ml were seeded in 24-well tissue culture plates and allowed to attach overnight, after which cells were treated with different concentrations of GaPcCl, InPcCl and FePcCl ranging from 2 μg/ml to 100 μg/ml. After 2h, cells were irradiated with constant light doses of 2.5 J/cm(2), 4.5 J/cm(2) and 8.5 J/cm(2) delivered from a diode laser (λ = 661 nm). Post-irradiated cells were incubated for 24h before cell viability was measured using the MTT Assay. At 24h after PDT, irradiation with a light dose of 2.5 J/cm(2) for each photosensitizing concentration of GaPcCl, InPcCl and FePcCl produced a significant decrease in cell viability, but when the treatment light dose was further increased to 4.5 J/cm(2) and 8.5 J/cm(2) the cell survival was less than 40%. Results also showed that photoactivated FePcCl decreased cell survival of A549 cells to 0% with photosensitizing concentrations of 40 μg/ml and treatment light dose of 2.5 J/cm(2). A 20 μg/ml photosensitizing concentration of FePcCl in combination with an increased treatment light dose of either 4.5 J/cm(2) or 8.5 J/cm(2) also resulted in 0% cell survival. This PDT study concludes that low concentrations on GaPcCl, InPcCl and FePcCl activated with low level light doses can be used for the effective in vitro killing of lung cancer cells. Copyright © 2013 Elsevier B.V. All rights reserved.

Radiochromic film dosimetry for UV-C treatments of apple fruit

USDA-ARS?s Scientific Manuscript database

Radiochromic films were evaluated for their suitability to estimate UV-C doses and dose uniformity on apple fruit surface. Parameters investigated included film type, color changes of the films in response to different UV-C doses, color stability of films, UV-C light intensity, and temperature. In...

Mild skin photosensitivity in cancer patients following injection of Photochlor (2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a; HPPH) for photodynamic therapy.

PubMed

Bellnier, David A; Greco, William R; Nava, Hector; Loewen, Gregory M; Oseroff, Allan R; Dougherty, Thomas J

2006-01-01

To measure skin photosensitivity in cancer patients infused with the new second-generation photodynamic sensitizer Photochlor (2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a). A major disadvantage of using the clinically approved photosensitizer Photofrin is potentially prolonged and sometimes severe cutaneous phototoxicity. Forty-eight patients enrolled in Phases 1 and 2 clinical trials underwent two or more exposures to four graded doses (44.4, 66.6, 88.8 or 133.2 J/cm2) of artificial solar-spectrum light (SSL) before and after administration of Photochlor at a dose of 2.5, 3, 4, 5 or 6 mg/m2 . The most severe skin response, experienced by only six of the subjects, was limited to erythema without edema and could only be elicited by exposure to the highest light dose. Conversely, eight subjects had no discernible reaction to SSL at any light dose. For nearly all the patients, the peak skin response was obtained when the interval between sensitizer injection and exposure to SSL was 1 day and, generally, their sensitivity to SSL decreased with increasing sensitizer-light interval. For example, a 2-day sensitizer-SSL interval resulted in less severe reactions than those obtained with the 1-day interval in 79% of the subjects, while 90% of the subjects exposed to SSL 3 days after Photochlor infusion had responses that were less severe than those obtained with either the 1- or 2-day sensitizer-SSL interval. Photochlor, at clinically effective antitumor doses, causes only mild skin photosensitivity that declines rapidly over a few days.

Functional and histological bladder damage in mice after photodynamic therapy: the influence of sensitiser dose and time of administration.

PubMed Central

Stewart, F. A.; Oussoren, Y.

1993-01-01

The bladders of anaesthetised mice were illuminated with red laser light (630 nm) at intervals of 1 day to 4 weeks after i.p. administration of Photofrin. Light was delivered intravesically by inserting a fibre optic, with a diffusing bulb tip, into the centre of fluid filled bladders. A single light dose of 11.3 J cm-2 applies 1 day after 10 mg kg-1 Photofrin caused a severe acute response, with increased urination frequency (five to seven times control) and hematuria. Recovery was good, however, and by 10 weeks only a mild (approximately two-fold) increase in frequency remained. There was no reduction in the amount of acute bladder damage or in the rate of healing when the interval between Photofrin and light was increased from 1 to 7 days but a 2 to 3 week interval lead to a significant reduction in damage. For an interval of 4 weeks there was only a mild (less than two-fold) increase in urination frequency during the first week. A drug dose of 2.5 mg kg-1 given 1 day before illumination caused transient haematuria but no increase in urination frequency. Doses of 5, 7.5 or 10 mg kg-1 all caused photosensitisation and the amount of bladder damage was drug dose dependent. The bladder seems to be well able to recover from severe acute damage induced by PDT. Occasional incidences of pyelonephritis were seen, however, suggesting that urinary tract infection during the acute period may lead to permanent renal damage. Images Figure 5 PMID:8398691

Antimicrobial photodynamic therapy of S. mutans biofilms attached to relevant dental materials.

PubMed

Zoccolillo, Michelle L; Rogers, Stephen C; Mang, Thomas S

2016-12-01

Antimicrobial Photodynamic therapy (aPDT) has demonstrated efficacy in situations where conventional antibiotic therapies can be challenged such as biofilms, gram-negative bacteria, and antimicrobial resistant organisms. Surface characteristics can affect biofilm adherence and integrity and so may modify the effectiveness of aPDT. This study investigates the killing efficacy of aPDT on S. mutans biofilms grown on relevant dental substrata, examining the killing efficacy and specifically the effects of aPDT on the biofilm matrix architecture. S. mutans (NCTC 10449) was grown in 48 hours biofilms on different substrata, specifically glass, titanium, and denture acrylic. During aPDT assays, the biofilms were treated with a purpurin based sensitizer ([25 ug/ml] in DMSO) for 30 minutes, then exposed to a 664 nm diode laser at light doses of 15, 30, and 45 J/cm 2 . Colony forming unit assays were performed to determine survival following treatment. Controls for comparison in survival assays consisted of (No light/No PS; No light/PS; and No light/DMSO). MAIR-IR spectroscopy analysis was performed to investigate aPDT effects on biofilm composition before and after jet impingement. Survival was greatly reduced in the biofilm cultures following the aPDT assays. All light doses achieved a greater then 3-log inactivation on 48 hours biofilms grown on polished denture acrylic. The higher light doses (45 and 30 J) achieved greater than 3-log inactivation in 48 hours biofilms grown on glass. The higher light doses (30 and 45 J/cm 2 ) produced a 2-log inactivation in 48 hours biofilms grown on titanium. Multiple attenuated internal reflection infrared (MAIR-IR) spectroscopy data demonstrates enhanced loss of exopolysaccharide (EPS) and Amide in the aPDT treated biofilms following jet impingement. Antimicrobial PDT experiments using a purpurin based sensitizer and laser light doses of 15, 30, and 45 J/cm 2 , against S. mutans biofilm grown on different surfaces, show the effectiveness of this therapy. In CFU survival assays, a dose response to the laser is evident. While considerable disinfection was achieved on all surfaces compared to the controls, not all surfaces could be disinfected equally. MAIR-IR spectroscopy showed that aPDT groups lost more EPS and Amide versus controls, suggesting aPDT induced biofilm embrittlement, which was revealed by jet impingement. With demonstrated efficacy against various microbes and on different substrata, antimicrobial aPDT shows potential for clinical application in biofilm-mediated diseases such as peri-implantitis and periodontitis. Lasers Surg. Med. 48:995-1005, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

[Inactivation and reactivation of antibiotic-resistant bacteria during and after UV disinfection in reclaimed water].

PubMed

Huang, Jing-Jing; Tang, Fang; Xi, Jin-Ying; Pang, Yu-Chen; Hu, Hong-Ying

2014-04-01

Prevalence of antibiotic-resistant bacteria in wastewater effluents is concerned as an emerging contaminant. To estimate inactivation and reactivation potentials of antibiotic-resistant bacteria by UV disinfection, inactivation and reactivation of penicillin-, ampicillin-, cephalexin-, chloramphenicol-and rifampicin-resistant bacteria in the secondary effluent were studied under different UV doses. The results showed that the inactivation ratios of penicillin-, ampicillin-, cephalexin-and chloramphenicol-resistant bacteria were higher than 4-log, which was closed to that of total heterotrophic bacteria; however, the inactivation ratio of rifampicin-resistant bacteria was lower (3.7-log) under 20 mJ x cm(-2) UV exposure. After 22 h standing incubation, antibiotic-resistant bacteria widely reactivated. The colony forming ability of antibiotic-resistant bacteria was as high as 3-log when exposed to 20 mJ x cm(-2) UV light. Hence, conventional UV dose can not effectively control reactivation of antibiotic-resistant bacteria in reclaimed water by UV disinfection.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hancock, R.L.

Irradiation effects in the phylum Annelida are almost entirely unknown, nor is it know why the LD/sub 50/30// for amoebae is 100 kr, whereas mammals show LD/sub 50/ doses of approximates 0.5 kr. To shed more light on comparative radiosensitivity, Lumbricus terrestris was irradiated at a rate of 1 kr/min with 250-kr x rays to total doses of 10 to l00 kr. No lethal effect occurs at 45 kr or below in Lumbricus, whereas a definite mortality occurs with 75 kr. All worms died within 2 months after 100 kr. The LD/sub 50/35//and LD/sub 100/67// are approximates 100 kr. Thismore » is in contrast to the mollusk Radix which has a for lethal effects. The annelid Enchytraeus shows no apparent effect after 90 kr. It is suggested that some feature of biological organization, which has up to the present escaped discovery, may hold a clue to the fundamental nature of radiobiological action, and may explain the extremes of radiosensitivity present within a few selected invertebrate types. (BBB)« less

Manipulating the mitochondria activity in human hepatic cell line Huh7 by low-power laser irradiation

PubMed Central

Lynnyk, Anna; Lunova, Mariia; Jirsa, Milan; Egorova, Daria; Kulikov, Andrei; Kubinová, Šárka; Lunov, Oleg; Dejneka, Alexandr

2018-01-01

Low-power laser irradiation of red light has been recognized as a promising tool across a vast variety of biomedical applications. However, deep understanding of the molecular mechanisms behind laser-induced cellular effects remains a significant challenge. Here, we investigated mechanisms involved in the death process in human hepatic cell line Huh7 at a laser irradiation. We decoupled distinct cell death pathways targeted by laser irradiations of different powers. Our data demonstrate that high dose laser irradiation exhibited the highest levels of total reactive oxygen species production, leading to cyclophilin D-related necrosis via the mitochondrial permeability transition. On the contrary, low dose laser irradiation resulted in the nuclear accumulation of superoxide and apoptosis execution. Our findings offer a novel insight into laser-induced cellular responses, and reveal distinct cell death pathways triggered by laser irradiation. The observed link between mitochondria depolarization and triggering ROS could be a fundamental phenomenon in laser-induced cellular responses. PMID:29541521

Hydrocortisone Therapy in Catecholamine-Resistant Pediatric Septic Shock: A Pragmatic Analysis of Clinician Practice and Association With Outcomes.

PubMed

Nichols, Blake; Kubis, Sherri; Hewlett, Jennifer; Yehya, Nadir; Srinivasan, Vijay

2017-09-01

The 2012 Surviving Sepsis Campaign pediatric guidelines recommend stress dose hydrocortisone in children experiencing catecholamine-dependent septic shock with suspected or proven absolute adrenal insufficiency. We evaluated whether stress dose hydrocortisone therapy in children with catecholamine dependent septic shock correlated with random serum total cortisol levels and was associated with improved outcomes. Retrospective cohort study. Non-cardiac PICU. Critically ill children (1 mo to 18 yr) admitted between January 1, 2013, and December 31, 2013, with catecholamine dependent septic shock who had random serum total cortisol levels measured prior to potential stress dose hydrocortisone therapy. None. The cohort was dichotomized to random serum total cortisol less than 18 mcg/dL and greater than or equal to 18 mcg/dL. Associations of stress dose hydrocortisone with outcomes: PICU mortality, PICU and hospital length of stay, ventilator-free days, and vasopressor-free days were examined. Seventy children with catecholamine-dependent septic shock and measured random serum total cortisol levels were eligible (16% PICU mortality). Although 43% (30/70) had random serum total cortisol less than 18 μg/dL, 60% (42/70) received stress dose hydrocortisone. Children with random serum total cortisol less than 18 μg/dL had lower severity of illness and lower Vasopressor Inotrope Scores than those with random serum total cortisol greater than or equal to 18 μg/dL (all p < 0.05). Children with stress dose hydrocortisone had higher severity of illness and PICU mortality than those without stress dose hydrocortisone (all p < 0.05). Mean random serum total cortisol levels were similar in children with and without stress dose hydrocortisone (21.1 vs 18.7 μg/dL; p = 0.69). In children with random serum total cortisol less than 18 μg/dL, stress dose hydrocortisone was associated with greater PICU and hospital length of stay and fewer ventilator-free days (all p < 0.05). In children with random serum total cortisol greater than 18 μg/dL, stress dose hydrocortisone was associated with greater PICU mortality and fewer ventilator-free days and vasopressor-free days (all p < 0.05). Stress dose hydrocortisone therapy in children with catecholamine-dependent septic shock correlated more with severity of illness than random serum total cortisol levels and was associated with worse outcomes, irrespective of random serum total cortisol levels.

Protective Effect of Hericium erinaceus on Alcohol Induced Hepatotoxicity in Mice

PubMed Central

Hao, Lijun; Xie, Yuxi; Wu, Guikai; Cheng, Aibin; Liu, Xiaogang; Zheng, Rongjuan; Huo, Hong; Zhang, Junwei

2015-01-01

We investigated the effects of Hericium erinaceus (HEM) on liver injury induced by acute alcohol administration in mice. Mice received ethanol (5 g/kg BW) by gavage every 12 hrs for a total of 3 doses. HEM (200 mg/kg BW) was gavage before ethanol administration. Subsequent serum alanine aminotransferase (ALT) level, aspartate aminotransaminase (AST) level, Maleic dialdehyde (MDA) level, hepatic total antioxidant status (TAOS), and activated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were determined by ELISA and immunohistochemistry, respectively. HEM administration markedly (P < 0.05) decreased serum ALT, AST, and MDA levels. The hepatic histopathological observations showed that HEM had a relatively significant role in mice model, which had alcoholic liver damage. In conclusion, we observed that HEM (200 mg/kg BW) supplementation could restrain the hepatic damage caused by acute alcohol exposure. PMID:25960751

Protective Effect of Hericium erinaceus on Alcohol Induced Hepatotoxicity in Mice.

PubMed

Hao, Lijun; Xie, Yuxi; Wu, Guikai; Cheng, Aibin; Liu, Xiaogang; Zheng, Rongjuan; Huo, Hong; Zhang, Junwei

2015-01-01

We investigated the effects of Hericium erinaceus (HEM) on liver injury induced by acute alcohol administration in mice. Mice received ethanol (5 g/kg BW) by gavage every 12 hrs for a total of 3 doses. HEM (200 mg/kg BW) was gavage before ethanol administration. Subsequent serum alanine aminotransferase (ALT) level, aspartate aminotransaminase (AST) level, Maleic dialdehyde (MDA) level, hepatic total antioxidant status (TAOS), and activated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were determined by ELISA and immunohistochemistry, respectively. HEM administration markedly (P < 0.05) decreased serum ALT, AST, and MDA levels. The hepatic histopathological observations showed that HEM had a relatively significant role in mice model, which had alcoholic liver damage. In conclusion, we observed that HEM (200 mg/kg BW) supplementation could restrain the hepatic damage caused by acute alcohol exposure.

Study of the effect of temperature on the optical properties of Latin skins

NASA Astrophysics Data System (ADS)

Quistián-Vázquez, Brenda; Morales-Cruzado, Beatriz; Sarmiento-Gómez, Erick; Pérez-Gutiérrez, Francisco G.

2017-02-01

Photodynamic therapy (PDT) is a very effective technique for treatment of certain types of cancer, among the most common, skin cancer. PDT requires the presence of three elements: the photosensitizer, light and oxygen. Penetration depth of light into the tumor depends on both the characteristics of the tissue to be treated and the wavelength. As the light dose to be delivered in each lesion depends on the optical properties of the tissue, all the effects that change these properties should be considered in order to choose suitable doses. There are some studies that have determined the maximum dose of radiation tolerated for certain types of skin, but the influence of the temperature on the optical properties, especially for darker skin types, remains unknown. In this study, we analyzed the optical properties of skin in vivo of different Latin volunteers in order to study the influence of the temperature on the optical properties and thereby to define more precisely the dose of light to be received by each patient in a personalized way. The optical properties of skin in vivo were investigated using an optical system that included an integrating sphere, a tungsten lamp and a spectrophotometer. Such experimental set up-allowed to obtain spectra reflectance of various volunteers and from this measurement, the absorption coefficient was recovered by Inverse Adding Doubling (IAD) program.

Efficiency of photodynamic therapy using indocyanine green and infrared light on MCF-7 breast cancer cells in vitro

NASA Astrophysics Data System (ADS)

Ruhi, Mustafa K.; Ak, Ayşe.; Gülsoy, Murat

2016-03-01

Cancer is one of the main reasons of death in all around the world. The main treatments of cancer include surgical intervention, radiation therapy and chemotherapy. These treatments can be applied separately or in a combined manner. Another therapeutic method that is still being researched and recently has started to be used in clinical applications is Photodynamic Therapy (PDT). Most photosensitizers currently being investigated are sensitive to red light. However, it is known that infrared light has a better penetration into the skin or tissue. Indocyanine Green (ICG), which is used in this study, is sensitive to infrared light. The aim of this in vitro study is to investigate the effect of PDT on breast cancer cells by using different doses of ICG and infrared light irradiation. 25, 50 and 100 μM ICG concentrations and 25 and 50 J/cm2 laser energy doses were applied to MCF-7 cell lines. MTT analyses were performed on 24, 48 and 72 hours following the treatments. As a result, inhibition of cell viability was observed in a time and dose dependent manner. It can be concluded that ICG-PDT application is a good alternative to conventional radiation therapy and chemotherapy for breast cancer treatment.

SU-G-BRB-14: Uncertainty of Radiochromic Film Based Relative Dose Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devic, S; Tomic, N; DeBlois, F

2016-06-15

Purpose: Due to inherently non-linear dose response, measurement of relative dose distribution with radiochromic film requires measurement of absolute dose using a calibration curve following previously established reference dosimetry protocol. On the other hand, a functional form that converts the inherently non-linear dose response curve of the radiochromic film dosimetry system into linear one has been proposed recently [Devic et al, Med. Phys. 39 4850–4857 (2012)]. However, there is a question what would be the uncertainty of such measured relative dose. Methods: If the relative dose distribution is determined going through the reference dosimetry system (conversion of the response bymore » using calibration curve into absolute dose) the total uncertainty of such determined relative dose will be calculated by summing in quadrature total uncertainties of doses measured at a given and at the reference point. On the other hand, if the relative dose is determined using linearization method, the new response variable is calculated as ζ=a(netOD)n/ln(netOD). In this case, the total uncertainty in relative dose will be calculated by summing in quadrature uncertainties for a new response function (σζ) for a given and the reference point. Results: Except at very low doses, where the measurement uncertainty dominates, the total relative dose uncertainty is less than 1% for the linear response method as compared to almost 2% uncertainty level for the reference dosimetry method. The result is not surprising having in mind that the total uncertainty of the reference dose method is dominated by the fitting uncertainty, which is mitigated in the case of linearization method. Conclusion: Linearization of the radiochromic film dose response provides a convenient and a more precise method for relative dose measurements as it does not require reference dosimetry and creation of calibration curve. However, the linearity of the newly introduced function must be verified. Dave Lewis is inventor and runs a consulting company for radiochromic films.« less

Four-Dimensional Patient Dose Reconstruction for Scanned Ion Beam Therapy of Moving Liver Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richter, Daniel; TU Darmstadt, Darmstadt; Saito, Nami

2014-05-01

Purpose: Estimation of the actual delivered 4-dimensional (4D) dose in treatments of patients with mobile hepatocellular cancer with scanned carbon ion beam therapy. Methods and Materials: Six patients were treated with 4 fractions to a total relative biological effectiveness (RBE)–weighted dose of 40 Gy (RBE) using a single field. Respiratory motion was addressed by dedicated margins and abdominal compression (5 patients) or gating (1 patient). 4D treatment dose reconstructions based on the treatment records and the measured motion monitoring data were performed for the single-fraction dose and a total of 17 fractions. To assess the impact of uncertainties in the temporalmore » correlation between motion trajectory and beam delivery sequence, 3 dose distributions for varying temporal correlation were calculated per fraction. For 3 patients, the total treatment dose was formed from the fractional distributions using all possible combinations. Clinical target volume (CTV) coverage was analyzed using the volumes receiving at least 95% (V{sub 95}) and 107% (V{sub 107}) of the planned doses. Results: 4D dose reconstruction based on daily measured data is possible in a clinical setting. V{sub 95} and V{sub 107} values for the single fractions ranged between 72% and 100%, and 0% and 32%, respectively. The estimated total treatment dose to the CTV exhibited improved and more robust dose coverage (mean V{sub 95} > 87%, SD < 3%) and overdose (mean V{sub 107} < 4%, SD < 3%) with respect to the single-fraction dose for all analyzed patients. Conclusions: A considerable impact of interplay effects on the single-fraction CTV dose was found for most of the analyzed patients. However, due to the fractionated treatment, dose heterogeneities were substantially reduced for the total treatment dose. 4D treatment dose reconstruction for scanned ion beam therapy is technically feasible and may evolve into a valuable tool for dose assessment.« less

Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

PubMed Central

Zhang, Yakun; Li, Xiang; Segars, W. Paul; Samei, Ehsan

2014-01-01

Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definium 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDIvol and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose metrics only increased slightly for radiographic modalities and for chest tomosynthesis. Effective and organ doses normalized to mAs all illustrated an exponential decrease with increasing patient size. As a surface organ, breast doses had less correlation with body size than that of lungs or liver. Conclusions: Patient body size has a much greater impact on radiation dose of chest CT examinations than chest radiography and tomosynthesis. The size of a patient should be considered when choosing the best thoracic imaging modality. PMID:24506654

Preliminary investigations on the determination of three-dimensional dose distributions using scintillator blocks and optical tomography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroll, Florian; Karsch, Leonhard; Pawelke, Jörg

2013-08-15

Purpose: Clinical QA in teletherapy as well as the characterization of experimental radiation sources for future medical applications requires effective methods for measuring three-dimensional (3D) dose distributions generated in a water-equivalent medium. Current dosimeters based on ionization chambers, diodes, thermoluminescence detectors, radiochromic films, or polymer gels exhibit various drawbacks: High quality 3D dose determination is either very sophisticated and expensive or requires high amounts of effort and time for the preparation or read out. New detectors based on scintillator blocks in combination with optical tomography are studied, since they have the potential to facilitate the desired cost-effective, transportable, and long-termmore » stable dosimetry system that is able to determine 3D dose distributions with high spatial resolution in a short time.Methods: A portable detector prototype was set up based on a plastic scintillator block and four digital cameras. During irradiation the scintillator emits light, which is detected by the fixed cameras. The light distribution is then reconstructed by optical tomography, using maximum-likelihood expectation maximization. The result of the reconstruction approximates the 3D dose distribution. First performance tests of the prototype using laser light were carried out. Irradiation experiments were performed with ionizing radiation, i.e., bremsstrahlung (6 to 21 MV), electrons (6 to 21 MeV), and protons (68 MeV), provided by clinical and research accelerators.Results: Laser experiments show that the current imaging properties differ from the design specifications: The imaging scale of the optical systems is position dependent, ranging from 0.185 mm/pixel to 0.225 mm/pixel. Nevertheless, the developed dosimetry method is proven to be functional for electron and proton beams. Induced radiation doses of 50 mGy or more made 3D dose reconstructions possible. Taking the imaging properties into account, determined dose profiles are in agreement with reference measurements. An inherent drawback of the scintillator is the nonlinear light output for high stopping-power radiation due to the quenching effect. It impacts the depth dose curves measured with the dosimeter. For single Bragg peak distributions this leads to a peak to plateau ratio of 2.8 instead of 4.5 for the reference ionization chamber measurement. Furthermore, the transmission of the clinical bremsstrahlung beams through the scintillator leads to the saturation of one camera, making dose reconstructions in that case presently not feasible.Conclusions: It is shown that distributions of scintillation light generated by proton or electron beams can be reconstructed by the dosimetry system within minutes. The quenching apparent for proton irradiation, and the yet not precisely determined position dependency of the imaging scale, require further investigation and corrections. Upgrading the prototype with larger or inorganic scintillators would increase the detectable proton and electron energy range. The presented results show that the determination of 3D dose distributions using scintillator blocks and optical tomography is a promising dosimetry method.« less

Preliminary investigations on the determination of three-dimensional dose distributions using scintillator blocks and optical tomography.

PubMed

Kroll, Florian; Pawelke, Jörg; Karsch, Leonhard

2013-08-01

Clinical QA in teletherapy as well as the characterization of experimental radiation sources for future medical applications requires effective methods for measuring three-dimensional (3D) dose distributions generated in a water-equivalent medium. Current dosimeters based on ionization chambers, diodes, thermoluminescence detectors, radiochromic films, or polymer gels exhibit various drawbacks: High quality 3D dose determination is either very sophisticated and expensive or requires high amounts of effort and time for the preparation or read out. New detectors based on scintillator blocks in combination with optical tomography are studied, since they have the potential to facilitate the desired cost-effective, transportable, and long-term stable dosimetry system that is able to determine 3D dose distributions with high spatial resolution in a short time. A portable detector prototype was set up based on a plastic scintillator block and four digital cameras. During irradiation the scintillator emits light, which is detected by the fixed cameras. The light distribution is then reconstructed by optical tomography, using maximum-likelihood expectation maximization. The result of the reconstruction approximates the 3D dose distribution. First performance tests of the prototype using laser light were carried out. Irradiation experiments were performed with ionizing radiation, i.e., bremsstrahlung (6 to 21 MV), electrons (6 to 21 MeV), and protons (68 MeV), provided by clinical and research accelerators. Laser experiments show that the current imaging properties differ from the design specifications: The imaging scale of the optical systems is position dependent, ranging from 0.185 mm/pixel to 0.225 mm/pixel. Nevertheless, the developed dosimetry method is proven to be functional for electron and proton beams. Induced radiation doses of 50 mGy or more made 3D dose reconstructions possible. Taking the imaging properties into account, determined dose profiles are in agreement with reference measurements. An inherent drawback of the scintillator is the nonlinear light output for high stopping-power radiation due to the quenching effect. It impacts the depth dose curves measured with the dosimeter. For single Bragg peak distributions this leads to a peak to plateau ratio of 2.8 instead of 4.5 for the reference ionization chamber measurement. Furthermore, the transmission of the clinical bremsstrahlung beams through the scintillator leads to the saturation of one camera, making dose reconstructions in that case presently not feasible. It is shown that distributions of scintillation light generated by proton or electron beams can be reconstructed by the dosimetry system within minutes. The quenching apparent for proton irradiation, and the yet not precisely determined position dependency of the imaging scale, require further investigation and corrections. Upgrading the prototype with larger or inorganic scintillators would increase the detectable proton and electron energy range. The presented results show that the determination of 3D dose distributions using scintillator blocks and optical tomography is a promising dosimetry method.

System responses to equal doses of photosynthetically usable radiation of blue, green, and red light in the marine diatom Phaeodactylum tricornutum.

PubMed

Valle, Kristin Collier; Nymark, Marianne; Aamot, Inga; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Brembu, Tore; Bones, Atle M

2014-01-01

Due to the selective attenuation of solar light and the absorption properties of seawater and seawater constituents, free-floating photosynthetic organisms have to cope with rapid and unpredictable changes in both intensity and spectral quality. We have studied the transcriptional, metabolic and photo-physiological responses to light of different spectral quality in the marine diatom Phaeodactylum tricornutum through time-series studies of cultures exposed to equal doses of photosynthetically usable radiation of blue, green and red light. The experiments showed that short-term differences in gene expression and profiles are mainly light quality-dependent. Transcription of photosynthesis-associated nuclear genes was activated mainly through a light quality-independent mechanism likely to rely on chloroplast-to-nucleus signaling. In contrast, genes encoding proteins important for photoprotection and PSII repair were highly dependent on a blue light receptor-mediated signal. Changes in energy transfer efficiency by light-harvesting pigments were spectrally dependent; furthermore, a declining trend in photosynthetic efficiency was observed in red light. The combined results suggest that diatoms possess a light quality-dependent ability to activate photoprotection and efficient repair of photodamaged PSII. In spite of approximately equal numbers of PSII-absorbed quanta in blue, green and red light, the spectral quality of light is important for diatom responses to ambient light conditions.

Inactivation of Escherichia coli in milk and concentrated milk using pulsed-light treatment.

PubMed

Miller, B M; Sauer, A; Moraru, C I

2012-10-01

Pulsed light (PL) treatment has been viewed as an alternative to thermal treatments for the inactivation of pathogenic and spoilage microorganisms in recent years. The objectives of this study were to quantify the effectiveness of PL on inactivating Escherichia coli in cow milk and to evaluate the effect of total solids and fat content on inactivation. Samples of reconstituted milk with variable total solids levels (9.8, 25, and 45%) and commercial cow milk with different fat contents (skim milk, 2% fat, and whole milk) were inoculated with nonpathogenic E. coli ATCC 25922 at a concentration of 10(7)cfu/mL. One milliliter of the inoculated sample was placed in a thin layer in a glass chamber and exposed to PL doses of up to 14.9 J/cm(2), both in static mode and turbulent mode. Survivors were quantified using standard plate counting. All experiments were performed in triplicate. Pulsed light treatment of the concentrated milks of 25 and 45% solids content resulted in reductions of less than 1 log, even in turbulent mode, whereas for the milk with 9.8% solids content, reduction levels of 2.5 log cfu were obtained after treatment with 8.4 J/cm(2) in turbulent mode. In the skim milk, a 3.4 log cfu reduction at 14.9 J/cm(2) was obtained and a plateau of the inactivation curve typical of PL treatment was not achieved. Under the same conditions, both 2% and whole milk attained inactivation levels greater than 2.5 log cfu. These data indicate that PL is effective for the inactivation of E. coli in milk, but has limited effectiveness for microbial inactivation in concentrated milk, due to the absorption of light by the milk solids and shielding of the bacteria in the concentrated substrates. Milk fat also diminishes the effectiveness of PL to some extent, due to light-scattering effects. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Institutional Tuberculosis Transmission. Controlled Trial of Upper Room Ultraviolet Air Disinfection: A Basis for New Dosing Guidelines.

PubMed

Mphaphlele, Matsie; Dharmadhikari, Ashwin S; Jensen, Paul A; Rudnick, Stephen N; van Reenen, Tobias H; Pagano, Marcello A; Leuschner, Wilhelm; Sears, Tim A; Milonova, Sonya P; van der Walt, Martie; Stoltz, Anton C; Weyer, Karin; Nardell, Edward A

2015-08-15

Transmission is driving the global tuberculosis epidemic, especially in congregate settings. Worldwide, natural ventilation is the most common means of air disinfection, but it is inherently unreliable and of limited use in cold climates. Upper room germicidal ultraviolet (UV) air disinfection with air mixing has been shown to be highly effective, but improved evidence-based dosing guidelines are needed. To test the efficacy of upper room germicidal air disinfection with air mixing to reduce tuberculosis transmission under real hospital conditions, and to define the application parameters responsible as a basis for proposed new dosing guidelines. Over an exposure period of 7 months, 90 guinea pigs breathed only untreated exhaust ward air, and another 90 guinea pigs breathed only air from the same six-bed tuberculosis ward on alternate days when upper room germicidal air disinfection was turned on throughout the ward. The tuberculin skin test conversion rates (>6 mm) of the two chambers were compared. The hazard ratio for guinea pigs in the control chamber converting their skin test to positive was 4.9 (95% confidence interval, 2.8-8.6), with an efficacy of approximately 80%. Upper room germicidal UV air disinfection with air mixing was highly effective in reducing tuberculosis transmission under hospital conditions. These data support using either a total fixture output (rather than electrical or UV lamp wattage) of 15-20 mW/m(3) total room volume, or an average whole-room UV irradiance (fluence rate) of 5-7 μW/cm(2), calculated by a lighting computer-assisted design program modified for UV use.

Comparison of the efficacy of gamma and UV irradiation in sanitization of fresh carrot juice

NASA Astrophysics Data System (ADS)

Jo, Cheorun; Lee, Kyung Haeng

2012-08-01

As there is no pasteurization procedure for the manufacture of fresh vegetable juice, both industry and consumers have sought a method for improving the storage stability and shelf-life of this category of products. In this study, the effects of commercially available, non-thermal pasteurization processes, such as gamma and UV irradiation, were compared for their efficacy in sanitizing fresh carrot juice (FCJ). FCJ was manufactured, packaged, and gamma irradiated with doses of 0, 1, 3, and 5 kGy. The manufactured FCJ was also passed through 4 UV light lamps at doses of 3.67, 4.69, and 6.50 kGy. The total aerobic bacterial count of the FCJ approached the legal limit (105 CFU/mL) after manufacturing. Both treatments were effective in reducing the number of total aerobic bacteria, and the reduced number was maintained during storage for 7 days. Gamma irradiation was more effective in suppressing microbial growth during storage. When the doses for UV treatment and gamma irradiation were higher, the inactivation effects were higher. The reduction of ascorbic acid content was greater upon gamma irradiation than UV treatment. No difference was found in the contents of flavonoids and polyphenols in FCJ after either treatment. After 3 days of refrigerated storage, the sensory scores of gamma- or UV-irradiated FCJ were superior to those of the control. The results indicate that both non-thermal treatments were effective in improving storage stability and extending shelf-life, but gamma irradiation was slightly better in suppressing microbial growth after treatment.

Skin color and tissue thickness effects on transmittance, reflectance, and skin temperature when using 635 and 808 nm lasers in low intensity therapeutics.

PubMed

Souza-Barros, Leanna; Dhaidan, Ghaith; Maunula, Mikko; Solomon, Vaeda; Gabison, Sharon; Lilge, Lothar; Nussbaum, Ethne L

2018-04-01

To examine the role of skin color and tissue thickness on transmittance, reflectance, and skin heating using red and infrared laser light. Forty volunteers were measured for skin color and skin-fold thickness at a standardized site near the elbow. Transmittance, reflectance and skin temperature were recorded for energy doses of 2, 6, 9, and 12 Joules using 635 nm (36 mW) and 808 nm (40 mW) wavelength laser diodes with irradiances within American National Standards Institute safety guidelines (4.88 mm diameter, 0.192 W/cm 2 and 4.88 mm diameter, 0.214 W/cm 2 , respectively). The key factors affecting reflectance to an important degree were skin color and wavelength. However, the skin color effects were different for the two wavelengths: reflectance decreased for darker skin with a greater decrease for red light than near infrared light. Transmittance was greater using 808 nm compared with 635 nm. However, the effect was partly lost when the skin was dark rather than light, and was increasingly lost as tissue thickness increased. Dose had an increasing effect on temperature (0.7-1.6°C across the 6, 9, and 12 J doses); any effects of wavelength, skin color, and tissue thickness were insignificant compared to dose effects. Subjects themselves were not aware of the increased skin temperature. Transmittance and reflectance changes as a function of energy were very small and likely of no clinical significance. Absorption did not change with higher energy doses and increasing temperature. Skin color and skin thickness affect transmittance and reflectance of laser light and must be accounted for when selecting energy dose to ensure therapeutic effectiveness at the target tissue. Skin heating appears not to be a concern when using 635 and 808 nm lasers at energy doses of up to 12 J and irradiance within American National Standards Institute standards. Photobiomodulation therapy should never exceed the American National Standards Institute recommendation for the maximum permissible exposure to the skin. Lasers Surg. Med. 50:291-301, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Live-cell imaging.

PubMed

Cole, Richard

2014-01-01

It would be hard to argue that live-cell imaging has not changed our view of biology. The past 10 years have seen an explosion of interest in imaging cellular processes, down to the molecular level. There are now many advanced techniques being applied to live cell imaging. However, cellular health is often under appreciated. For many researchers, if the cell at the end of the experiment has not gone into apoptosis or is blebbed beyond recognition, than all is well. This is simply incorrect. There are many factors that need to be considered when performing live-cell imaging in order to maintain cellular health such as: imaging modality, media, temperature, humidity, PH, osmolality, and photon dose. The wavelength of illuminating light, and the total photon dose that the cells are exposed to, comprise two of the most important and controllable parameters of live-cell imaging. The lowest photon dose that achieves a measureable metric for the experimental question should be used, not the dose that produces cover photo quality images. This is paramount to ensure that the cellular processes being investigated are in their in vitro state and not shifted to an alternate pathway due to environmental stress. The timing of the mitosis is an ideal canary in the gold mine, in that any stress induced from the imaging will result in the increased length of mitosis, thus providing a control model for the current imagining conditions.

Live-cell imaging

PubMed Central

Cole, Richard

2014-01-01

It would be hard to argue that live-cell imaging has not changed our view of biology. The past 10 years have seen an explosion of interest in imaging cellular processes, down to the molecular level. There are now many advanced techniques being applied to live cell imaging. However, cellular health is often under appreciated. For many researchers, if the cell at the end of the experiment has not gone into apoptosis or is blebbed beyond recognition, than all is well. This is simply incorrect. There are many factors that need to be considered when performing live-cell imaging in order to maintain cellular health such as: imaging modality, media, temperature, humidity, PH, osmolality, and photon dose. The wavelength of illuminating light, and the total photon dose that the cells are exposed to, comprise two of the most important and controllable parameters of live-cell imaging. The lowest photon dose that achieves a measureable metric for the experimental question should be used, not the dose that produces cover photo quality images. This is paramount to ensure that the cellular processes being investigated are in their in vitro state and not shifted to an alternate pathway due to environmental stress. The timing of the mitosis is an ideal canary in the gold mine, in that any stress induced from the imaging will result in the increased length of mitosis, thus providing a control model for the current imagining conditions. PMID:25482523

Gemfibrozil in late preterm and term neonates with moderate jaundice: a randomized controlled trial.

PubMed

Jaikrishan; Kumar, Praveen; Narang, Anil

2009-12-01

To determine, if oral Gemfibrozil is effective in decreasing the duration of phototherapy by at least 24 hours in neonates >34 weeks gestation with non-hemolytic jaundice, as compared to placebo. Double blind placebo controlled randomized controlled trial. Tertiary care neonatal unit in north India. Ninety seven neonates >34 weeks gestation with non-hemolytic jaundice within first 7 days of life requiring phototherapy. Two doses of Gemfibrozil (60 mg/kg/dose) or placebo, 12 hours apart. Babies were treated with single surface special blue light phototherapy. Serum total bilirubin (STB) was measured 8 hourly. Phototherapy was stopped if two consecutive STB values were below phototherapy zone. Duration of phototherapy. The median (IQR) duration of phototherapy was 40 (30, 60) hours in Gemfibrozil and 36 (19, 55) hours in the placebo group (P=0.13). The peak STB levels were 16.8 +/- 2.7 mg/dL and 16.3 +/- 2.3 mg/dL in Gemfibrozil and placebo groups, respectively. No side effect of the drug or placebo was noticed. Two doses of gemfibrozil (60 mg/kg/dose) given 12 hours apart were not able to reduce the duration of phototherapy, or peak bilirubin level in babies > 34 weeks gestation with non-hemolytic jaundice in the first week of life. Gemfibrozil was not associated with any side effects.

Diffuse reflectance spectra measured in vivo in human tissues during Photofrin-mediated pleural photodynamic therapy

NASA Astrophysics Data System (ADS)

Finlay, Jarod C.; Zhu, Timothy C.; Dimofte, Andreea; Friedberg, Joseph S.; Hahn, Stephen M.

2006-02-01

Optimal delivery of light in photodynamic therapy (PDT) requires not only optimal placement and power of light sources, but knowledge of the dynamics of light propagation in the tissue being treated and in the surrounding normal tissue, and of their respective accumulations of sensitizer. In an effort to quantify both tissue optical properties and sensitizer distribution, we have measured fluorescence emission and diffuse reflectance spectra at the surface of a variety of tissue types in the thoracic cavities of human patients. The patients studied here were enrolled in Phase II clinical trials of Photofrin-mediated PDT for the treatment of non-small cell lung cancer and cancers with pleural effusion. Patients were given Photofrin at dose of 2 mg per kg body weight 24 hours prior to treatment. Each patient received surgical resection of the affected lung and pleura. Patients received intracavity PDT at 630nm to a dose of 30 J/cm2, as determined by isotropic detectors sutured to the cavity walls. We measured the diffuse reflectance spectra before and after PDT in various positions within the cavity, including tumor, diaphragm, pericardium, skin, and chest wall muscle in 5 patients. The measurements we acquired using a specially designed fiber optic-based probe consisting of one fluorescence excitation fiber, one white light delivery fiber, and 9 detection fibers spaced at distances from 0.36 to 7.8 mm from the source, all of which are imaged via a spectrograph onto a CCD, allowing measurement of radially-resolved diffuse reflectance and fluorescence spectra. The light sources for these two measurements (a 403-nm diode laser and a halogen lamp, respectively) were blocked by computer-controlled shutters, allowing sequential fluorescence, reflectance, and background acquisition. The diffuse reflectance was analyzed to determine the absorption and scattering spectra of the tissue and from these, the concentration and oxygenation of hemoglobin and the local drug uptake. The total hemoglobin concentration in normal tissues varied from 50 to 300 µM, and the oxygen saturation was generally above 60%. One tumor measured exhibited higher hemoglobin concentration and lower saturation.

Visible optical radiation generates bactericidal effect applicable for inactivation of health care associated germs demonstrated by inactivation of E. coli and B. subtilis using 405-nm and 460-nm light emitting diodes

NASA Astrophysics Data System (ADS)

Hönes, Katharina; Stangl, Felix; Sift, Michael; Hessling, Martin

2015-07-01

The Ulm University of Applied Sciences is investigating a technique using visible optical radiation (405 nm and 460 nm) to inactivate health-hazardous bacteria in water. A conceivable application could be point-of-use disinfection implementations in developing countries for safe drinking water supply. Another possible application field could be to provide sterile water in medical institutions like hospitals or dental surgeries where contaminated pipework or long-term disuse often results in higher germ concentrations. Optical radiation for disinfection is presently mostly used in UV wavelength ranges but the possibility of bacterial inactivation with visible light was so far generally disregarded. One of the advantages of visible light is, that instead of mercury arc lamps, light emitting diodes could be used, which are commercially available and therefore cost-efficient concerning the visible light spectrum. Furthermore they inherit a considerable longer life span than UV-C LEDs and are non-hazardous in contrast to mercury arc lamps. Above all there are specific germs, like Bacillus subtilis, which show an inactivation resistance to UV-C wavelengths. Due to the totally different deactivation mechanism even higher disinfection rates are reached, compared to Escherichia coli as a standard laboratory germ. By 460 nm a reduction of three log-levels appeared with Bacillus subtilis and a half log-level with Escherichia coli both at a dose of about 300 J/cm². By the more efficient wavelength of 405 nm four and a half log-levels are reached with Bacillus subtilis and one and a half log-level with Escherichia coli also both at a dose of about 300 J/cm². In addition the employed optical setup, which delivered a homogeneous illumination and skirts the need of a stirring technique to compensate irregularities, was an important improvement compared to previous published setups. Evaluated by optical simulation in ZEMAX® the designed optical element provided proven homogeneity distributions with maximum variation of ± 10 %.

Histologic changes associated with talaporfin sodium-mediated photodynamic therapy in rat skin.

PubMed

Moy, Wesley J; Yao, Jonathan; de Feraudy, Sébastien M; White, Sean M; Salvador, Jocelynda; Kelly, Kristen M; Choi, Bernard

2017-10-01

Alternative treatments are needed to achieve consistent and more complete port wine stain (PWS) removal, especially in darker skin types; photodynamic therapy (PDT) is a promising alternative treatment. To this end, we previously reported on Talaporfin Sodium (TS)-mediated PDT. It is essential to understand treatment tissue effects to design a protocol that will achieve selective vascular injury without ulceration and scarring. The objective of this work is to assess skin changes associated with TS-mediated PDT with clinically relevant treatment parameters. We performed TS (0.75 mg/kg)-mediated PDT (664 nm) on Sprague Dawley rats. Radiant exposures were varied between 15 and 100 J/cm 2 . We took skin biopsies from subjects at 9 hours following PDT. We assessed the degree and depth of vascular and surrounding tissue injury using histology and immunohistochemical staining. TS-mediated PDT at 0.75 mg/kg combined with 15 and 25 J/cm 2 light doses resulted in vascular injury with minimal epidermal damage. At light dose of 50 J/cm 2 , epidermal damage was noted with vascular injury. At light doses >50 J/cm 2 , both vascular and surrounding tissue injury were observed in the forms of vasculitis, extravasated red blood cells, and coagulative necrosis. Extensive coagulative necrosis involving deeper adnexal structures was observed for 75 and 100 J/cm 2 light doses. Observed depth of injury increased with increasing radiant exposure, although this relationship was not linear. TS-mediated PDT can cause selective vascular injury; however, at higher light doses, significant extra-vascular injury was observed. This information can be used to contribute to design of safe protocols to be used for treatment of cutaneous vascular lesions. Lasers Surg. Med. 49:767-772, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Virus Characterization by FFF-MALS Assay

NASA Astrophysics Data System (ADS)

Razinkov, Vladimer

2009-03-01

Adequate biophysical characterization of influenza virions is important for vaccine development. The influenza virus vaccines are produced from the allantoic fluid of developing chicken embryos. The process of viral replication produces a heterogeneous mixture of infectious and non-infectious viral particles with varying states of aggregation. The study of the relative distribution and behavior of different subpopulations and their inter-correlation can assist in the development of a robust process for a live virus vaccine. This report describes a field flow fractionation and multiangle light scattering (FFF-MALS) method optimized for the analysis of size distribution and total particle counts. A method using a combination of asymmetric flow field-flow fractionation (AFFFF) and multiangle light scattering (MALS) techniques has been shown to improve the estimation of virus particle counts and the amount of aggregated virus in laboratory samples. The FFF-MALS method was compared with several other methods such as transmission electron microscopy (TEM), atomic force microscopy (AFM), size exclusion chromatography followed by MALS (SEC-MALS), quantitative reverse transcription polymerase chain reaction (RT Q-PCR), median tissue culture dose (TCID(50)), and the fluorescent focus assay (FFA). The correlation between the various methods for determining total particle counts, infectivity and size distribution is reported. The pros and cons of each of the analytical methods are discussed.

Conformational Effects of UV Light on DNA Origami.

PubMed

Chen, Haorong; Li, Ruixin; Li, Shiming; Andréasson, Joakim; Choi, Jong Hyun

2017-02-01

The responses of DNA origami conformation to UV radiation of different wavelengths and doses are investigated. Short- and medium-wavelength UV light can cause photo-lesions in DNA origami. At moderate doses, the lesions do not cause any visible defects in the origami, nor do they significantly affect the hybridization capability. Instead, they help relieve the internal stress in the origami structure and restore it to the designed conformation. At high doses, staple dissociation increases which causes structural disintegration. Long-wavelength UV does not show any effect on origami conformation by itself. We show that this UV range can be used in conjunction with photoactive molecules for photo-reconfiguration, while avoiding any damage to the DNA structures.

Analysis of gamma ray dose for dried up pond storing low enriched UO2 fuel

NASA Astrophysics Data System (ADS)

Nauchi, Yasushi; Suzuki, Motomu

2017-09-01

Gamma ray dose is calculated for loss of coolant accident in spent fuel pond (SFP) storing irradiated fuels used in light water reactors. Influence of modelling of fuel assemblies, source distributions, and loading fraction of fuel assemblies in the fuel rack on the dose are investigated.

Assessment of radiation doses from residential smoke detectors that contain americium-241

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Donnell, F.R.; Etnier, E.L.; Holton, G.A.

1981-10-01

External dose equivalents and internal dose commitments were estimated for individuals and populations from annual distribution, use, and disposal of 10 million ionization chamber smoke detectors that contain 110 kBq (3 ..mu..Ci) americium-241 each. Under exposure scenarios developed for normal distribution, use, and disposal using the best available information, annual external dose equivalents to average individuals were estimated to range from 4 fSv (0.4 prem) to 20 nSv (2 ..mu..rem) for total body and from 7 fSv to 40 nSv for bone. Internal dose commitments to individuals under post disposal scenarios were estimated to range from 0.006 to 80 ..mu..Svmore » (0.0006 to 8 mrem) to total body and from 0.06 to 800 ..mu..Sv to bone. The total collective dose (the sum of external dose equivalents and 50-year internal dose commitments) for all individuals involved with distribution, use, or disposal of 10 million smoke detectors was estimated to be about 0.38 person-Sv (38 person-rem) to total body and 00 ft/sup 2/).« less

Amorphous and crystalline optical materials used as instruments for high gamma radiation doses estimations

NASA Astrophysics Data System (ADS)

Ioan, M.-R.

2016-06-01

Nuclear radiation induce some changes to the structure of exposed materials. The main effect of ionizing radiation when interacting with optical materials is the occurrence of color centers, which are quantitatively proportional to the up-taken doses. In this paper, a relation between browning effect magnitude and dose values was found. Using this relation, the estimation of a gamma radiation dose can be done. By using two types of laser wavelengths (532 nm and 633 nm), the optical powers transmitted thru glass samples irradiated to different doses between 0 and 59.1 kGy, were measured and the associated optical browning densities were determined. The use of laser light gives the opportunity of using its particularities: monochromaticity, directionality and coherence. Polarized light was also used for enhancing measurements quality. These preliminary results bring the opportunity of using glasses as detectors for the estimation of the dose in a certain point in space and for certain energy, especially in particles accelerators experiments, where the occurred nuclear reactions are involving the presence of high gamma rays fields.

Study on the Dose Uncertainties in the Lung during Passive Proton Irradiation with a Proton Beam Range Compensator

NASA Astrophysics Data System (ADS)

Yoo, Seung Hoon; Son, Jae Man; Yoon, Myonggeun; Park, Sung Yong; Shin, Dongho; Min, Byung Jun

2018-06-01

A moving phantom is manufactured for mimicking lung model to study the dose uncertainty from CT number-stopping power conversion and dose calculation in the soft tissue, light lung tissue and bone regions during passive proton irradiation with compensator smearing value. The phantom is scanned with a CT system, and a proton beam irradiation plan is carried out with the use of a treatment planning system (Eclipse). In the case of the moving phantom, a RPM system is used for respiratory gating. The uncertainties in the dose distribution between the measured data and the planned data are investigated by a gamma analysis with 3%-3 mm acceptance criteria. To investigate smearing effect, three smearing values (0.3 cm, 0.7 cm, 1.2 cm) are used to for fixed and moving phantom system. For both fixed and moving phantom, uncertainties in the light lung tissue are severe than those in soft tissue region in which the dose uncertainties are within clinically tolerable ranges. As the smearing value increases, the uncertainty in the proton dose distribution decreases.

In vitro bactericidal activity of blue light (465 nm) phototherapy on meticillin-susceptible and meticillin-resistant Staphylococcus pseudintermedius.

PubMed

Schnedeker, Amy H; Cole, Lynette K; Lorch, Gwendolen; Diaz, Sandra F; Bonagura, John; Daniels, Joshua B

2017-10-01

Staphylococcus pseudintermedius is the most common cause of bacterial skin infections in dogs. Meticillin-resistant infections have become more common and are challenging to treat. Blue light phototherapy may be an option for treating these infections. The objective of this study was to measure the in vitro bactericidal activity of 465 nm blue light on meticillin-susceptible Staphylococcus pseudintermedius (MSSP) and meticillin-resistant Staphylococcus pseudintermedius (MRSP). We hypothesized that irradiation with blue light would kill MSSP and MRSP in a dose-dependent fashion in vitro as previously reported for meticillin-resistant Staphylococcus aureus (MRSA). In six replicate experiments, each strain [MSSP, n = 1; MRSP ST-71 (KM1381) n = 1; and MRSA (BAA-1680) n = 1] were cultivated on semisolid media, irradiated using a 465 nm blue light phototherapeutic device at the cumulative doses of 56.25, 112.5 and 225 J/cm 2 and incubated overnight at 35°C. Controls were not irradiated. Colony counts (CC) were performed manually. Descriptive statistics were performed and treatment effects assessed using the Wilcoxon-Mann-Whitney rank-sum test. Bonferroni-corrected rank-sum tests were performed for post hoc analysis when significant differences were identified. There was a significant decrease in CC with blue light irradiation at all doses for MRSA (P = 0.0006) but not for MSSP (P = 0.131) or MRSP (P = 0.589). Blue light phototherapy significantly reduced CC of MRSA, but not of MSSP or MRSP. The mechanism for the relative photosensitivity of the MRSA isolate is unknown, but is hypothesized to be due to an increased concentration of porphyrin in S. aureus relative to S. pseudintermedius, which would modulate blue light absorption. © 2017 ESVD and ACVD.

Photodynamic treatment of basal cell carcinoma and squamous cell carcinoma with hypericin.

PubMed

Alecu, M; Ursaciuc, C; Hãlãlãu, F; Coman, G; Merlevede, W; Waelkens, E; de Witte, P

1998-01-01

Hypericin displays antiproliferative and cytotoxic effects on tumor cells. This effect depends on photodynamic activation with visible light and oxygen. Hence, we explored its potential use in treating skin cancer. Eight patients with squamous cell carcinoma (SCC) and eleven patients with basal cell carcinoma (BCC) were treated topically with hypericin. After intralesional injection, the hypericin was irradiated with visible light. Patients with SCC were given 40-100 micrograms hypericin intralesionally, 3-5 times per week for 2-4 weeks; patients with BCC 40-200 micrograms hypericin 3-5 times per week for 2-6 weeks. Hypericin displayed selective tumor-targeting: penetration in the surrounding tissues did not induce necrosis or cell loss and even the generation of a new epithelium at the surface of the malignancy was noticed. The effectiveness of the therapy depends on the concentration and total dose of hypericin, the frequency and duration of the therapy; clinical remissions can be expected after 6-8 weeks.

A comparative analysis of warfarin and low-dose heparin as thromboembolism prophylaxis in total hip replacement patinets.

PubMed Central

Ritter, M A; HamiltonCW

1975-01-01

Warfarin, low-dose heparin, or a combination of low-dose heparin and hydrocortisone was administered to 300 patients undergoing total hip replacement. The lowest incidence of thromboembolic (5 per cent) was attained with Warfarin. Further investigation into the method of administration of low-dose heparin is necessary before it can be used effectively as thromboembolism prophylaxis in total hip replacement patients. The addition of hydrocortisone was not found useful. PMID:1138642

Light-driven photosensitizer uptake increases Candida albicans photodynamic inactivation.

PubMed

Romano, Renan A; Pratavieira, Sebastião; Silva, Ana P da; Kurachi, Cristina; Guimarães, Francisco E G

2017-11-01

Photodynamic Inactivation (PDI) is based on the use of a photosensitizer (PS) and light that results mainly in the production of reactive oxygen species, aiming to produce microorganism cell death. PS incubation time and light dose are key protocol parameters that influence PDI response; the correct choice of them can increase the efficiency of inactivation. The results of this study show that a minor change in the PDI protocol, namely light-driven incubation leads to a higher photosensitizer and more uniform cell uptake inside the irradiated zone. Furthermore, as the uptake increases, the damage caused by PDI also increases. The proposed light-driven incubation prior to the inactivation illumination dose has advantages when compared to the traditional PDI treatments since it can be more selective and effective. Using a violet light as pre-illumination (light-driven incubation) source and a red-light system as PDI source, it was possible to demonstrate that when compared to the traditional protocol of dark incubation, the pre-illuminated cell culture showed an inactivation increase of 7 log units. These in vitro results performed in Candida albicans cells may result in the introduction of a new protocol for PDI. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

SU-E-T-169: Initial Investigation into the Use of Optically Stimulated Luminescent Dosimeters (OSLDs) for In-Vivo Dosimetry of TBI Patients.

PubMed

Paloor, S; Aland, T; Mathew, J; Al-Hammadi, N; Hammoud, R

2012-06-01

To report on an initial investigation into the use of optically stimulated luminescent dosimeters (OSLDs) for in-vivo dosimetry for total body irradiation (TBI) treatments. Specifically, we report on the determination of angular dependence, sensitivity correction factors and the dose calibration factors. The OSLD investigated in our work was InLight/OSL nanoDot dosimeters (Landauer Inc.). Nanodots are 5 mm diameter, 0.2 mm thick disk-shaped Carbon-doped Al2O3, and were read using a Landauer InLight microstar reader and associated software.OSLDs were irradiated under two setup conditions: a) typical clinical reference conditions (95cm SSD, 5cm depth in solid water, 10×10 cm field size), and b) TBI conditions (520cm SSD, 5cm depth in solid water, 40×40 cm field size,). The angular dependence was checked for angles ranging ±60 degree from normal incidence. In order to directly compare the sensitivity correction factors, a common dose was delivered to the OSLDs for the two setups. Pre- and post-irradiation readings were acquired. OSLDs were optically annealed under various techniques (1) by keeping over a film view box, (2) Using multiple scan on a flat bed optical scanner and (3) Using natural room light. Under reference conditions, the calculated sensitivity correction factors of the OSLDs had a SD of 2.2% and a range of 5%. Under TBI conditions, the SD increased to 3.4% and the range to 6.0%. The variation in sensitivity correction factors between individual OSLDs across the two measurement conditions was up to 10.3%. Angular dependence of less than 1% is observed. The best bleaching method we found is to keep OSLDs for more than 3 hours on a film viewer which will reduce normalized response to less than 1%. In order to obtain the most accurate results when using OSLDs for in-vivo dosimetry for TBI treatments, sensitivity correction factors and dose calibration factors should all be determined under clinical TBI conditions. © 2012 American Association of Physicists in Medicine.

Comparative studies on the conformational change and aggregation behavior of irradiated carrageenans and agar by dynamic light scattering.

PubMed

Abad, Lucille; Okabe, Satoshi; Shibayama, Mitsuhiro; Kudo, Hisaaki; Saiki, Seiichi; Aranilla, Charito; Relleve, Lorna; de la Rosa, Alumanda

2008-01-01

The conformational associative properties of kappa-, iota-, and lambda-carrageenan and agar with irradiation dose were studied by dynamic light scattering. The random scission of the carrageenans and agar by gamma irradiation resulted in the formation of polydispersed lower molecular weight fragments. At high doses, the system moves towards uniformity. Conformational change from coil to helix was observed in all carrageenans and agar at doses up to 100 kGy. The conformational change in lambda-carrageenan may be due to the irregular and hybrid structure of this polysaccharide. Only agar and lambda-carrageenan still undergo conformational transition at a high dose of 200 kGy. Gelation is observed for kappa-, iota-carrageenan up to a dose of 50 kGy while gelation is still observed at 100 kGy for agar. Increase in the hydrodynamic radius with decreasing temperatures for the non-irradiated carrageenans follows this order: lambda-carrageenan>kappa-carrageenan>iota-carrageenan. Slight increases in hydrodynamic radius were observed with irradiation.

Effect of Light Intensity and Photoperiod on Growth and Biochemical Composition of a Local Isolate of Nostoc calcicola.

PubMed

Khajepour, Fateme; Hosseini, Seyed Abbas; Ghorbani Nasrabadi, Rasoul; Markou, Giorgos

2015-08-01

A study was conducted to investigate the effect of light intensity (21, 42, and 63 μmol photons m(-2) s(-1)) and photoperiod (8:16, 12:12, and 16:8 h light/dark) on the biomass production and its biochemical composition (total carotenoids, chlorophyll a, phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC), total protein, and carbohydrates) of a local isolate of Nostoc calcicola. The results revealed that N. calcicola prefers dim light; however, the most of the levels of light intensity and photoperiod investigated did not have a significant impact on biomass production. Increasing light intensity biomass content of chlorophyll a, PE, PC, APC, and total protein decreased, while total carotenoids and carbohydrate increased. The same behavior was observed also when light duration (photoperiod) increased. The interaction effect of increasing light intensity and photoperiod resulted in an increase of carbohydrate and total carotenoids, and to the decrease of chlorophyll a, PE, PC, APC, and total protein content. The results indicate that varying the light regime, it is capable to manipulate the biochemical composition of the local isolate of N. calcicola, producing either valuable phycobiliproteins or proteins under low light intensity and shorter photoperiods, or producing carbohydrates and carotenoids under higher light intensities and longer photoperiods.

Scattering and absorption control in biocompatible fibers towards equalized photobiomodulation.

PubMed

George, J; Haghshenas, H; d'Hemecourt, D; Zhu, W; Zhang, L; Sorger, V

2017-03-01

Transparent tissue scaffolds enable illumination of growing tissue to accelerate cell proliferation and improve other cell functions through photobiomodulation. The biphasic dose response of cells exposed to photobiomodulating light dictates that the illumination be evenly distributed across the scaffold such that the cells are neither under nor over exposed to light. However, equalized illumination has not been sufficiently addressed. Here we analyze and experimentally demonstrate spatially equalizing illumination by three methods, namely: engineered surface scattering, reflection by a gold mirror, and traveling-waves in a ring mesh. Our results show that nearly equalized illumination is achievable by controlling the light scattering-to-loss ratio. This demonstration furthers opportunities for dose-optimized photobiomodulation in tissue regeneration.

Estimation of immunization providers' activities cost, medication cost, and immunization dose errors cost in Iraq.

PubMed

Al-lela, Omer Qutaiba B; Bahari, Mohd Baidi; Al-abbassi, Mustafa G; Salih, Muhannad R M; Basher, Amena Y

2012-06-06

The immunization status of children is improved by interventions that increase community demand for compulsory and non-compulsory vaccines, one of the most important interventions related to immunization providers. The aim of this study is to evaluate the activities of immunization providers in terms of activities time and cost, to calculate the immunization doses cost, and to determine the immunization dose errors cost. Time-motion and cost analysis study design was used. Five public health clinics in Mosul-Iraq participated in the study. Fifty (50) vaccine doses were required to estimate activities time and cost. Micro-costing method was used; time and cost data were collected for each immunization-related activity performed by the clinic staff. A stopwatch was used to measure the duration of activity interactions between the parents and clinic staff. The immunization service cost was calculated by multiplying the average salary/min by activity time per minute. 528 immunization cards of Iraqi children were scanned to determine the number and the cost of immunization doses errors (extraimmunization doses and invalid doses). The average time for child registration was 6.7 min per each immunization dose, and the physician spent more than 10 min per dose. Nurses needed more than 5 min to complete child vaccination. The total cost of immunization activities was 1.67 US$ per each immunization dose. Measles vaccine (fifth dose) has a lower price (0.42 US$) than all other immunization doses. The cost of a total of 288 invalid doses was 744.55 US$ and the cost of a total of 195 extra immunization doses was 503.85 US$. The time spent on physicians' activities was longer than that spent on registrars' and nurses' activities. Physician total cost was higher than registrar cost and nurse cost. The total immunization cost will increase by about 13.3% owing to dose errors. Copyright © 2012 Elsevier Ltd. All rights reserved.

The radiation dosimeter on-board the FY-4 Satellite

NASA Astrophysics Data System (ADS)

Zhang, B.; Sun, Y.; Zhang, S.; Zhang, X.; Sun, Y.; Jing, T.

2017-12-01

The total radiation dose effect can lead to a decrease in the performance of satellite devices or materials. Accurately obtaining the total radiation dose during satellite operation could help to analyze the abnormality of payloads in orbit and optimize the design of radiation shielding. The radiation dosimeter is one of the space environmental monitoring devices on the "FY-4" satellite, which is a new generation of geostationary meteorological satellite. The dosimeter consists of 8 detectors, which are installed in different locations of the satellite, to obtain the total radiation dose with different shielding thickness and different orientations. To measure a total radiation dose up to 2000krad(Si), 100nm ion implantation RADFET was used. To improve the sensitivity of the dosimeter, the bias voltage of RADFET is set to 15V, and a 10V, 15-bit A/D is adopted to digitalize the RADFET's threshold voltage, which is increased as the total radiation dose grows. In addition, the temperature effect of RADFET is corrected from the measured temperature on orbit. The preliminary monitoring results show that the radiation dose is less than 35rad (Si) per day at 0.87 mm shielding thickness of equivalent aluminum in the geostationary orbit, and the dose in Y direction of the satellite is less than those in the X and Z directions. The radiation dose at the thickness of 3.87 mm equivalent aluminum is less than 1rad(Si)/day. It is found that the daily total dose measured by the dosimeter has a strong correlation with the flux of high energy electrons.

The phototoxicity of phenothiazinium derivatives against Escherichia coli and Staphylococcus aureus.

PubMed

Phoenix, D A; Sayed, Z; Hussain, S; Harris, F; Wainwright, M

2003-10-24

Phenothiazinium dyes, and derivatives, were tested for toxicity to Escherichia coli and Staphylococcus aureus. The dyes were generally lipophilic (log P>1) and showed inherent dark toxicity (minimum lethal concentrations: 3.1-1000 microM). Dye illumination (total light dose of 3.15 J cm(-1) over 30 min) led to up to eight-fold reductions in minimum lethal concentrations. Most of the illuminated dyes showed significant relative singlet oxygen yields (phi'delta: 0.18-1.35) suggesting a type II mechanism of generating a phototoxic response. Although generally up to six-fold more effective against S. aureus, the dyes tested efficiently killed E. coli and may be of particular use in combating Gram-negative pathogens.

Rates of Change in Naturalistic Psychotherapy: Contrasting Dose-Effect and Good-Enough Level Models of Change

ERIC Educational Resources Information Center

Baldwin, Scott A.; Berkeljon, Arjan; Atkins, David C.; Olsen, Joseph A.; Nielsen, Stevan L.

2009-01-01

Most research on the dose-effect model of change has combined data across patients who vary in their total dose of treatment and has implicitly assumed that the rate of change during therapy is constant across doses. In contrast, the good-enough level model predicts that rate of change will be related to total dose of therapy. In this study, the…

Compendium of Current Total Ionizing Dose and Displacement Damage Results from NASA Goddard Space Flight Center and NASA Electronic Parts and Packaging Program

NASA Technical Reports Server (NTRS)

Topper, Alyson D.; Campola, Michael J.; Chen, Dakai; Casey, Megan C.; Yau, Ka-Yen; Cochran, Donna J.; Label, Kenneth A.; Ladbury, Raymond L.; Mondy, Timothy K.; O'Bryan, Martha V.;

Reduction of Zika virus infectivity in platelet concentrates after treatment with ultraviolet C light and in plasma after treatment with methylene blue and visible light.

PubMed

Fryk, Jesse J; Marks, Denese C; Hobson-Peters, Jody; Watterson, Daniel; Hall, Roy A; Young, Paul R; Reichenberg, Stefan; Tolksdorf, Frank; Sumian, Chryslain; Gravemann, Ute; Seltsam, Axel; Faddy, Helen M

2017-11-01

Zika virus (ZIKV) has emerged as a potential threat to transfusion safety worldwide. Pathogen inactivation is one approach to manage this risk. In this study, the efficacy of the THERAFLEX UV-Platelets system and THERAFLEX MB-Plasma system to inactivate ZIKV in platelet concentrates (PCs) and plasma was investigated. PCs spiked with ZIKV were treated with the THERAFLEX UV-Platelets system at 0.05, 0.10, 0.15, and 0.20 J/cm 2 UVC. Plasma spiked with ZIKV was treated with the THERAFLEX MB-Plasma system at 20, 40, 60, and 120 J/cm 2 light at 630 nm with at least 0.8 µmol/L methylene blue (MB). Samples were taken before the first and after each illumination dose and tested for residual virus. For each system the level of viral reduction was determined. Treatment of PCs with THERAFLEX UV-Platelets system resulted in a mean of 5 log reduction in ZIKV infectivity at the standard UVC dose (0.20 J/cm 2 ), with dose dependency observed with increasing UVC dose. For plasma treated with MB and visible light, ZIKV infectivity was reduced by a mean of at least 5.68 log, with residual viral infectivity reaching the detection limit of the assay at 40 J/cm 2 (one-third the standard dose). Our study demonstrates that the THERAFLEX UV-Platelets system and THERAFLEX MB-Plasma system can reduce ZIKV infectivity in PCs and pooled plasma to the detection limit of the assays used. These findings suggest both systems have the capacity to be an effective option to manage potential ZIKV transfusion transmission risk. © 2017 AABB.

Visible absorption properties of radiation exposed XR type-T radiochromic film.

PubMed

Butson, Martin J; Cheung, Tsang; Yu, Peter K N

2004-10-07

The visible absorption spectra of Gafchromic XR type-T radiochromic film have been investigated to analyse the dosimetry characteristics of the film with visible light densitometers. Common densitometers can use photospectrometry, fluorescent light (broad-band visible), helium neon (632 nm), light emitting diode (LED) or other specific bandwidth spectra. The visible absorption spectra of this film when exposed to photon radiation show peaks at 676 nm and 618 nm at 2 Gy absorbed doses which shift to slightly lower wavelengths (662 nm and 612 nm at 8 Gy absorbed dose) at higher doses. This is similar to previous models of Gafchromic film such as MD-55-2 and HS but XR type-T also includes a large absorption at lower visible wavelengths due to 'yellow' dyes placed within the film to aid with visible recognition of the film exposure level. The yellow dye band pass is produced at approximately 520 nm to 550 nm and absorbs wavelengths lower than this value within the visible spectrum. This accounts for the colour change from yellow to brown through the added absorption in the red wavelengths with radiation exposure. The film produces a relatively high dose sensitivity with up to 0.25 OD units per Gy change at 672 nm at 100 kVp x-ray energy. Variations in dose sensitivity can be achieved by varying wavelength analysis.

SU-E-QI-15: Single Point Dosimetry by Means of Cerenkov Radiation Energy Transfer (CRET)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Volotskova, O; Jenkins, C; Xing, L

2014-06-15

Purpose: Cerenkov light is generated when a charged particles with energy greater then 250 keV, moves faster than the speed of light in a given medium. Both x-ray photons and electrons produce optical Cerenkov photons during the static megavoltage linear accelerator (LINAC) operational mode. Recently, Cerenkov radiation gained considerable interest as possible candidate as a new imaging modality. Optical signals generated by Cerenkov radiation may act as a surrogate for the absorbed superficial radiation dose. We demonstrated a novel single point dosimetry method for megavoltage photon and electron therapy utilizing down conversion of Cerenkov photons. Methods: The custom build signalmore » characterization system was used: a sample holder (probe) with adjacent light tight compartments was connected via fiber-optic cables to a photon counting photomultiplier tube (PMT). One compartment contains a medium only while the other contains medium and red-shifting nano-particles (Q-dots, nanoclusters). By taking the difference between the two signals (Cerenkov photons and CRET photons) we obtain a measure of the down-converted light, which we expect to be proportional to dose as measured with an adjacent ion chamber. Experimental results are compared to Monte Carlo simulations performed using the GEANT4 code. Results: The signal correlation between CR signal, CRET readings and dose produced by LINAC at a single point were investigated. The experimental results were compared with simulations. The dose linearity, signal to noise ratio and dose rate dependence were tested with custom build CRET based probe. Conclusion: Performance characteristics of the proposed single point CRET based probe were evaluated. The direct use of the induced Cerenkov emission and CRET in an irradiated single point volume as an indirect surrogate for the imparted dose was investigated. We conclude that CRET is a promising optical based dosimetry method that offers advantages over those already proposed.« less

Dose rate effects in the radiation damage of the plastic scintillators of the CMS hadron endcap calorimeter

DOE PAGES

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; ...

2016-10-07

We present measurements of the reduction of light output by plastic scintillators irradiated in the CMS detector during the 8 TeV run of the Large Hadron Collider and show that they indicate a strong dose rate effect. The damage for a given dose is larger for lower dose rate exposures. The results agree with previous measurements of dose rate effects, but are stronger due to the very low dose rates probed. Here, we show that the scaling with dose rate is consistent with that expected from diffusion effects.

Occupational radiation dose to eyes from endoscopic retrograde cholangiopancreatography procedures in light of the revised eye lens dose limit from the International Commission on Radiological Protection.

PubMed

O'Connor, U; Gallagher, A; Malone, L; O'Reilly, G

2013-02-01

Endoscopic retrograde cholangiopancreatography (ERCP) is a common procedure that combines the use of X-ray fluoroscopy and endoscopy for examination of the bile duct. Published data on ERCP doses are limited, including staff eye dose from ERCP. Occupational eye doses are of particular interest now as the International Commission on Radiological Protection (ICRP) has recommended a reduction in the dose limit to the lens of the eye. The aim of this study was to measure occupational eye doses obtained from ERCP procedures. A new eye lens dosemeter (EYE-D(™), Radcard, Krakow, Poland) was used to measure the ERCP eye dose, H(p)(3), at two endoscopy departments in Ireland. A review of radiation protection practice at the two facilities was also carried out. The mean equivalent dose to the lens of the eye of a gastroenterologist is 0.01 mSv per ERCP procedure with an undercouch X-ray tube and 0.09 mSv per ERCP procedure with an overcouch X-ray tube. Staff eye dose normalised to patient kerma area product is also presented. Staff eye doses in ERCP have the potential to exceed the revised ICRP limit of 20 mSv per annum when an overcouch X-ray tube is used. The EYE-D dosemeter was found to be a convenient method for measuring lens dose. Eye doses in areas outside of radiology departments should be kept under review, particularly in light of the new ICRP eye dose limit. Occupational eye lens doses from ERCP procedures have been established using a new commercially available dedicated H(p)(3) dosemeter.

A study on comparison of Gafchromic EBT2 film response under single and cumulative exposure conditions

PubMed Central

Ganapathy, K.; Kurup, P.G.G.; Murali, V.; Muthukumaran, M.; Velmurugan, J.

2013-01-01

Gafchromic films are used as dosimeter for in vivo and in phantom dose measurements. The dose response of Gafchromic EBT2 film under single and repeated exposure conditions is compared in this study to analyze the usability of Gafchromic EBT2 films in cumulative dose measurements. The post-irradiation change in response of the film is studied for up to 4 days after irradiation. The effect of repeated exposure to scanner light on the response of the film is also studied. To check usability of Gafchromic EBT2 films in cumulative dose measurements, three EBT2 films were exposed to a daily fraction dose of 100 cGy, 150 cGy and 200 cGy, respectively, for 4 days. The dose response of the films exposed to cumulative irradiation was compared with the dose measured from films exposed to the same dose but in a single exposure. It is observed that the post-irradiation darkening of the film does not saturate and continue to take place even 4 days after irradiation. The dose measured from the EBT2 films after 4 days from irradiation was around 2% higher than the dose measured from the same films at 24 hours post-irradiation. It was also observed that the repeated exposure to scanner light does not produce any significant change in the film response. The dose response of films exposed to cumulative irradiation agrees with the dose response of films exposed to the same dose in a single irradiation with less than 3% difference. Gafchromic EBT2 films can be used to measure the cumulative dose delivered over multiple fractions, when the delivered dose is uniform across the film. PMID:24672151

SU-F-T-550: Radiochromic Plastic Thin Sheet Dosimeter: Initial Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, K; Adamovics, J

Purpose: Thin sheets, of a high sensitivity formulation of radiochromic dosimeter, Presage were prepared and evaluated for optical readout. Methods: Sheets of radiochromic polyurethane, 12 cm long, 10 cm wide and 0.2 cm thick were prepared with leuco crystal violet as the reporter molecule. Sample transmission was evaluated at a wavelength of 590 nm with in-house constructed instruments: optical cone beam laser CT scanner, fixed and scanning spot densitometers. Sample sequential irradiations to a total dose of 40 Gy were conducted with a modified, Theratron 60, cobalt radiotherapy machine at dose rates of 1 or 0.25 Gy per minute. Exposuremore » to ambient and readout light was minimized to limit background photochromic signals. Samples were stored at 4°C. Optical activity was assessed from linearly polarized transmission images. Comparison sensitivity measurements with EBT3 film were conducted. Results: Samples were transparent, smooth and pale purple before irradiation. Radiochromic reaction was completed in less than 5 minutes. A linear dose response with a sensitivity of 0.5 cm-1Gy-1 was observed. Micrometer measurements found sheet thickness variations up to 20%. Uniform dose, 2 Gy attenuation images, correlated with local sheet thicknesses. Comparable measurements with EBT3 film were 3 times more sensitive at 1 Gy but above 15 Gy, EBT3 film had lower sensitivity than 0.2 cm thick Presage sheet dosimeter due to its non-linear response. Conclusion: Dose sensitivity provided a 10% decrease in transmission for a 1 Gy dose. Improvements in mold design are expected to allow production of sheets with less than 5% variation in thickness. Above, 10 Gy, Presage sheet dosimeter performance expected to exceed EBT3 film based on linearity, sensitivity, transparency and smoothness of samples. J Adamovics is owner of Heuris Inc.« less

Visualization of energy: light dose indicator based on electrochromic gyroid nano-materials

NASA Astrophysics Data System (ADS)

Wei, Di; Scherer, Maik R. J.; Astley, Michael; Steiner, Ullrich

2015-06-01

The typical applications of electrochromic devices do not make use of the charge-dependent, gradual optical response due to their slow voltage-sensitive coloration. However, in this paper we present a design for a reusable, self-powered light dose indicator consisting of a solar cell and a gyroid-structured nickel oxide (NiO) electrochromic display that measures the cumulative charge per se, making use of the efficient voltage-sensitive coloration of gyroid materials. To circumvent the stability issues associated with the standard aqueous electrolyte that is typically accompanied by water splitting and gas evolution, we investigate a novel nano-gyroid NiO electrochromic device based on organic solvents of 1,1,1,3,3,3-hexafluoropropan-2-ol, and room temperature ionic liquid (RTIL) triethylsulfonium bis(trifluoromethylsulfonyl) imide ([SET3][TFSI]) containing lithium bis(trifluoromethylsulfonyl) imide. We show that an effective light dose indicator can be enabled by nano-gyroid NiO with RTIL; this proves to be a reliable device since it does not involve solvent degradation or gas generation.

Continuing evaluation of bipolar linear devices for total dose bias dependency and ELDRS effects

NASA Technical Reports Server (NTRS)

McClure, Steven S.; Gorelick, Jerry L.; Yui, Candice; Rax, Bernard G.; Wiedeman, Michael D.

2003-01-01

We present results of continuing efforts to evaluate total dose bias dependency and ELDRS effects in bipolar linear microcircuits. Several devices were evaluated, each exhibiting moderate to significant bias and/or dose rate dependency.

Sensitivity of the human circadian pacemaker to nocturnal light: melatonin phase resetting and suppression

NASA Technical Reports Server (NTRS)

Zeitzer, J. M.; Dijk, D. J.; Kronauer, R.; Brown, E.; Czeisler, C.

2000-01-01

Ocular exposure to early morning room light can significantly advance the timing of the human circadian pacemaker. The resetting response to such light has a non-linear relationship to illuminance. The dose-response relationship of the human circadian pacemaker to late evening light of dim to moderate intensity has not been well established. Twenty-three healthy young male and female volunteers took part in a 9 day protocol in which a single experimental light exposure6.5 h in duration was given in the early biological night. The effects of the light exposure on the endogenous circadian phase of the melatonin rhythm and the acute effects of the light exposure on plasma melatonin concentration were calculated. We demonstrate that humans are highly responsive to the phase-delaying effects of light during the early biological night and that both the phase resetting response to light and the acute suppressive effects of light on plasma melatonin follow a logistic dose-response curve, as do many circadian responses to light in mammals. Contrary to expectations, we found that half of the maximal phase-delaying response achieved in response to a single episode of evening bright light ( approximately 9000 lux (lx)) can be obtained with just over 1 % of this light (dim room light of approximately 100 lx). The same held true for the acute suppressive effects of light on plasma melatonin concentrations. This indicates that even small changes in ordinary light exposure during the late evening hours can significantly affect both plasma melatonin concentrations and the entrained phase of the human circadian pacemaker.

Positive allosteric modulation of mGlu7 receptors by AMN082 affects sleep and wakefulness in the rat.

PubMed

Cavas, María; Scesa, Gianluigi; Navarro, José Francisco

2013-02-01

Evidence indicates that metabotropic glutamate receptors (mGlu) are involved in the regulation of physiological and behavioral processes, and glutamate has been implicated in several pathologies of the Central Nervous System. Pharmacological evidence suggests the therapeutic potential of targeting mGlu7 receptor in a number of pathological conditions; and previous research has shown the involvement of glutamate on sleep and wakefulness regulation. Here, the effects of mGlu7 receptor selective modulation on sleep and wake states are explored. 32 male Wistar rats were implanted with electrodes for recording sleep and wakefulness. N,N'-Bis(diphenylmethyl)-1,2-ethanediamine dihydrochloride (AMN082) (5, 10, and 20mg/kg, i.p.), a potent, selective and systemically active mGlu7 receptor positive allosteric modulator, or vehicle was administered 1 hour after the beginning of the light period. AMN082 (5 and 10mg/kg) significantly increased total time of sleep; and time spent on Slow Wave Sleep (SWS) was increased. AMN082 at 10mg/kg specifically affected Light SWS, increasing time spent on Light SWS. The highest dose of AMN082, 20mg/kg, significantly reduced time spent in Rapid Eye Movement (REM) sleep, decreasing the number of REM sleep episodes and their mean duration. Total time spent awake was increased and mean episode duration of wakefulness was prolonged. The present results suggest that mGlu7 receptors might be involved in sleep regulation and drugs targeting these receptors could affect sleep and wakefulness architecture. Copyright © 2012 Elsevier Inc. All rights reserved.

Early photosensitizer uptake kinetics predict optimum drug-light interval for photodynamic therapy

NASA Astrophysics Data System (ADS)

Sinha, Lagnojita; Elliott, Jonathan T.; Hasan, Tayyaba; Pogue, Brian W.; Samkoe, Kimberley S.; Tichauer, Kenneth M.

2015-03-01

Photodynamic therapy (PDT) has shown promising results in targeted treatment of cancerous cells by developing localized toxicity with the help of light induced generation of reactive molecular species. The efficiency of this therapy depends on the product of the intensity of light dose and the concentration of photosensitizer (PS) in the region of interest (ROI). On account of this, the dynamic and variable nature of PS delivery and retention depends on many physiological factors that are known to be heterogeneous within and amongst tumors (e.g., blood flow, blood volume, vascular permeability, and lymph drainage rate). This presents a major challenge with respect to how the optimal time and interval of light delivery is chosen, which ideally would be when the concentration of PS molecule is at its maximum in the ROI. In this paper, a predictive algorithm is developed that takes into consideration the variability and dynamic nature of PS distribution in the body on a region-by-region basis and provides an estimate of the optimum time when the PS concentration will be maximum in the ROI. The advantage of the algorithm lies in the fact that it predicts the time in advance as it takes only a sample of initial data points (~12 min) as input. The optimum time calculated using the algorithm estimated a maximum dose that was only 0.58 +/- 1.92% under the true maximum dose compared to a mean dose error of 39.85 +/- 6.45% if a 1 h optimal light deliver time was assumed for patients with different efflux rate constants of the PS, assuming they have the same plasma function. Therefore, if the uptake values of PS for the blood and the ROI is known for only first 12 minutes, the entire curve along with the optimum time of light radiation can be predicted with the help of this algorithm.

The effects of two different doses of ultraviolet-A light exposure on nitric oxide metabolites and cardiorespiratory outcomes.

PubMed

Monaghan, Chris; McIlvenna, Luke C; Liddle, Luke; Burleigh, Mia; Weller, Richard B; Fernandez, Bernadette O; Feelisch, Martin; Muggeridge, David J; Easton, Chris

2018-05-01

The present study investigated different doses of ultraviolet-A (UV-A) light on plasma nitric oxide metabolites and cardiorespiratory variables. Ten healthy male participants completed three experimental conditions, 7 days apart. Participants were exposed to no light (CON); 10 J cm 2 (15 min) of UV-A light (UVA10) and 20 J cm 2 (30 min) of UV-A light (UVA20) in a randomized order. Plasma nitrite [NO 2 - ] and nitrate [NO 3 - ] concentrations, blood pressure (BP), and heart rate (HR) were recorded before, immediately after exposure and 30 min post-exposure. Whole body oxygen utilization ([Formula: see text]), resting metabolic rate (RMR) and skin temperature were recorded continuously. None of the measured parameters changed significantly during CON (all P > 0.05). [Formula: see text] and RMR were significantly reduced immediately after UVA10 (P < 0.05) despite no change in plasma [NO 2 - ] (P > 0.05). Immediately after exposure to UVA20, plasma [NO 2 - ] was higher (P = 0.014) and [Formula: see text] and RMR tended to be lower compared to baseline (P = 0.06). There were no differences in [NO 2 - ] or [Formula: see text] at the 30 min time point in any condition. UV-A exposure did not alter systolic BP, diastolic BP or MAP (all P > 0.05). UV-A light did not alter plasma [NO 3 - ] at any time point (all P > 0.05). This study demonstrates that a UV-A dose of 20 J cm 2 is necessary to increase plasma [NO 2 - ] although a smaller dose is capable of reducing [Formula: see text] and RMR at rest. Exposure to UV-A did not significantly reduce BP in this cohort of healthy adults. These data suggest that exposure to sunlight has a meaningful acute impact on metabolic function.

LED array designing and its bactericidal effect researching on Pseudomonas aeruginosa in vitro

NASA Astrophysics Data System (ADS)

Fang, Jing; Xing, Jin; Gao, Liucun; Shen, Benjian; Kang, Hongxiang; Jie, Liang; Peng, Chen

2015-10-01

Lights with some special waveband and output power density have a bactericidal effect to some special bacteria. In this paper, the bactericidal effect of light at wavelength of 470 nm on P. aeruginosa (ATCC 27853) is researched with different irradiation dose. The light source is a LED array which is obtained by incoherent combine of 36 LEDs with emitting wavelength of 470 nm. The P. aeruginosa suspension is exposed with the LED array at the light power density of 100 mW/cm2 with exposures time of 0, 5, 10, 20, 40, and 80 min, respectively. The numbers of CFU are then determined by serial dilutions on LB agar plates. The bactericidal effect research results of 470 nm LED on P. aeruginosa show that the killing ratio increases with increasing of the exposure time. For the 80 min irradiation, as much as 92.4% reduction of P. aeruginosa is achieved. The results indicate that, in vitro, 470-nm lights produce dose dependent bactericidal effects on P. aeruginosa.

The effect of UV light on the inactivation of Giardia lamblia and Giardia muris cysts as determined by animal infectivity assay (P-2951-01).

PubMed

Mofidi, Alexander A; Meyer, Ernest A; Wallis, Peter M; Chou, Connie I; Meyer, Barbara P; Ramalingam, Shivaji; Coffey, Bradley M

2002-04-01

This study measured the effect of germicidal ultraviolet (UV) light on Giardia lamblia and Giardia muris cysts, as determined by their infectivity in Mongolian gerbils and CD-1 mice, respectively. Reduction of cyst infectivity due to UV exposure was quantified by applying most probable number techniques. Controlled bench-scale, collimated-beam tests exposed cysts suspended in filtered natural water to light from a low-pressure UV lamp. Both G. lamblia and G. muris cysts showed similar sensitivity to UV light. At 3 mJ/cm2, a dose 10-fold lower than what large-scale UV reactors may be designed to provide, > 2-log10 (99 percent) inactivation was observed. These results, combined with previously published data showing other protozoa and bacteria have similar, high sensitivity to UV light, establish that UV disinfection of drinking water is controlled by viruses which may require over 10-fold more UV dose for the same level of control.

Drinking and driving behavior at stop signs and red lights.

PubMed

Wan, Jingyan; Wu, Changxu; Zhang, Yiqi; Houston, Rebecca J; Chen, Chang Wen; Chanawangsa, Panya

2017-07-01

Alcohol is one of the principal risk factors for motor vehicle crashes. One factor that contributes to vehicle crashes is noncompliance with stop signs and red lights. The present experiment investigated the effects of alcohol and drinking patterns on driving behavior at stop signs and red lights. 28 participants participated in drinking and simulated driving sessions during which they received a moderate dose of alcohol (0.08% BAC) or a placebo. Simulated driving tasks measured participants' driving performance at stop signs and red lights in response to each dose. Results suggested that alcohol impaired the driver control of speed and direction and prolonged their simple and complex reaction time, which were exhibited by impaired speed and lateral control, longer reaction time when the lights turned yellow, and lower deceleration towards stop signs and red lights. Visual degradation may also occur under alcohol intake. It was also suggested that alcohol impaired non-binge drinkers more severely. To be specific, higher acceleration was observed in impaired non-binge drinkers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultraviolet-C efficacy against a norovirus surrogate and hepatitis A virus on a stainless steel surface.

PubMed

Park, Shin Young; Kim, An-Na; Lee, Ki-Hoon; Ha, Sang-Do

2015-10-15

In this study, the effects of 10-300 mWs/cm(2) of ultraviolet radiation (UV-C) at 260 nm were investigated for the inactivation of two foodborne viruses: murine norovirus-1 (MNV-1; a human norovirus [NoV] surrogate) and hepatitis A virus (HAV). We used an experimentally contaminated stainless steel surface, a common food-contact surface, to examine the effects of low doses of UV-C radiation on MNV-1 and HAV titers. The modified Gompertz equation was used to generate non-linear survival curves and calculate dR-values as the UV-C dose of 90% reduction for MNV-1 (R(2)=0.95, RMSE=0.038) and HAV (R(2)=0.97, RMSE=0.016). Total MNV-1 and HAV titers significantly decreased (p<0.05) with higher doses of UV-C. MNV-1 and HAV were reduced to 0.0-4.4 and 0.0-2.6 log10PFU/ml, respectively, on the stainless steel surfaces by low-dose UV-C treatment. The dR-value, 33.3 mWs/cm(2) for MNV-1 was significantly (p<0.05) lower than 55.4 mWs/cm(2) of HAV. Therefore, the present study shows that HAV is more resistant to UV-C radiation than MNV-1. These data suggest that low doses of UV-C light on food contact surfaces could be effective to inactivate human NoV and HAV in restaurant, institutional, and industrial kitchens and facilities. Copyright © 2015 Elsevier B.V. All rights reserved.

Explicit dosimetry for 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a-mediated photodynamic therapy: macroscopic singlet oxygen modeling.

PubMed

Penjweini, Rozhin; Liu, Baochang; Kim, Michele M; Zhu, Timothy C

2015-01-01

Type II photodynamic therapy (PDT) is based on the photochemical reactions mediated through an interaction between a photosensitizer, ground-state oxygen ([(3)O2]), and light excitation at an appropriate wavelength, which results in production of reactive singlet oxygen ([(1)O2]rx). We use an empirical macroscopic model based on four photochemical parameters for the calculation of [(1)O2]rx threshold concentration ([(1)O2]rx,sh) causing tissue necrosis in tumors after PDT. For this reason, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH)-mediated PDT was performed interstitially on mice with radiation-induced fibrosarcoma (RIF) tumors. A linear light source at 665 nm with total energy released per unit length of 12 to 100  J/cm and source power per unit length (LS) of 12 to 150  mW/cm was used to induce different radii of necrosis. Then the amount of [(1)O2]rx calculated by the macroscopic model incorporating explicit PDT dosimetry of light fluence distribution, tissue optical properties, and HPPH concentration was correlated to the necrotic radius to obtain the model parameters and [(1)O2]rx,sh. We provide evidence that [(1)O2]rx is a better dosimetric quantity for predicting the treatment outcome than PDT dose, which is proportional to the time integral of the products of the photosensitizer concentration and light fluence rate.

Explicit dosimetry for 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a-mediated photodynamic therapy: macroscopic singlet oxygen modeling

PubMed Central

Penjweini, Rozhin; Liu, Baochang; Kim, Michele M.; Zhu, Timothy C.

2015-01-01

Abstract. Type II photodynamic therapy (PDT) is based on the photochemical reactions mediated through an interaction between a photosensitizer, ground-state oxygen ([O32]), and light excitation at an appropriate wavelength, which results in production of reactive singlet oxygen ([O12]rx). We use an empirical macroscopic model based on four photochemical parameters for the calculation of [O12]rx threshold concentration ([O12]rx,sh) causing tissue necrosis in tumors after PDT. For this reason, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH)-mediated PDT was performed interstitially on mice with radiation-induced fibrosarcoma (RIF) tumors. A linear light source at 665 nm with total energy released per unit length of 12 to 100  J/cm and source power per unit length (LS) of 12 to 150  mW/cm was used to induce different radii of necrosis. Then the amount of [O12]rx calculated by the macroscopic model incorporating explicit PDT dosimetry of light fluence distribution, tissue optical properties, and HPPH concentration was correlated to the necrotic radius to obtain the model parameters and [O12]rx,sh. We provide evidence that [O12]rx is a better dosimetric quantity for predicting the treatment outcome than PDT dose, which is proportional to the time integral of the products of the photosensitizer concentration and light fluence rate. PMID:26720883

Explicit dosimetry for 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a-mediated photodynamic therapy: macroscopic singlet oxygen modeling

NASA Astrophysics Data System (ADS)

Penjweini, Rozhin; Liu, Baochang; Kim, Michele M.; Zhu, Timothy C.

2015-12-01

Type II photodynamic therapy (PDT) is based on the photochemical reactions mediated through an interaction between a photosensitizer, ground-state oxygen ([O]), and light excitation at an appropriate wavelength, which results in production of reactive singlet oxygen ([]rx). We use an empirical macroscopic model based on four photochemical parameters for the calculation of []rx threshold concentration ([]rx,sh) causing tissue necrosis in tumors after PDT. For this reason, 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH)-mediated PDT was performed interstitially on mice with radiation-induced fibrosarcoma (RIF) tumors. A linear light source at 665 nm with total energy released per unit length of 12 to 100 J/cm and source power per unit length (LS) of 12 to 150 mW/cm was used to induce different radii of necrosis. Then the amount of []rx calculated by the macroscopic model incorporating explicit PDT dosimetry of light fluence distribution, tissue optical properties, and HPPH concentration was correlated to the necrotic radius to obtain the model parameters and []rx,sh. We provide evidence that []rx is a better dosimetric quantity for predicting the treatment outcome than PDT dose, which is proportional to the time integral of the products of the photosensitizer concentration and light fluence rate.

A prospective, randomised, within-subject study of ALA-PDT for actinic keratoses using different irradiation regimes.

PubMed

Zaar, O; Sjöholm Hylén, A; Gillstedt, M; Paoli, J

2018-05-12

Photodynamic therapy (PDT) can be used to treat large fields of actinic keratoses (AKs) with high clearance rates. A notable downside is the amount of pain that accompany the treatment. This study aimed to optimise the illumination protocol during conventional PDT in order to reduce pain without compromising treatment effectiveness. In this prospective, randomised study with a split-face design, patients with, symmetrically distributed AKs were included. All patients were treated using a ALA 78 mg/g gel. One side was illuminated with the Aktilite ® CL-128 lamp and the other side with the RhodoLED ® lamp in which the light intensity gradually increased to a maximum of 60%. Both sides received a total light dose of 37 J/cm 2 . Pain during the treatment was measured using a visual analogue scale. The clinical effectiveness of the two treated sides was assessed after 12 weeks. 29 patients with 399 AKs were included. Illumination with the gradually increasing light intensity resulted in a decrease of the median VAS score by 1.1 points. Clearance rates were similar between the two lamps. Minimising the light intensity during the illumination phase of PDT reduces pain, while still preserving a high clearance rate of AKs. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Synthesis, characterization, and light-controlled antibiotic application of a composite material derived from polyurethane and silica xerogel with embedded photoactive manganese nitrosyl.

PubMed

Heilman, Brandon J; Halpenny, Genevieve M; Mascharak, Pradip K

2011-11-01

The synthesis of a light-sensitive polyurethane-based composite material (PUX-NO) is described. In its polyurethane medium, PUX-NO contains entrapped silica xerogel particles in which a photoactive manganese nitrosyl has been incorporated. Green flexible films of PUX-NO readily release nitric oxide (NO) only when exposed to low power (mW) visible light. Incorporation of the nitrosyl in the xerogel not only retains the nitrosyl (NO donor) within the composite material but also provides the right extent of hydration. Pre-swelled films of PUX-NO have water content close to 30 Wt % and such films can be stored for months under slightly moist condition without loss in NO-delivering capacity. The NO-releasing parameters of the film have been determined. The NO-releasing capacity of PUX-NO films can be conveniently altered by changing the amount of the nitrosyl as well as the thickness of the films. Patches of PUX-NO film have been successfully employed to reduce drastically bacterial loads of both gram-positive and gram-negative bacteria including methicillin-resistant Staphylococcus aureus and Acinetobacter baumannii under the total control of light. Effective control of infections by these bacterial pathogens via delivery of proper doses of NO only to the sites of infection appears feasible with PUX-NO films. 2011 Wiley Periodicals, Inc.

Selective effects of two systemic fungicides on soil fungi.

PubMed

Abdel-Fattah, H M; Abdel-Kader, M I; Hamida, S

1982-08-20

BAS 317 00F was not toxic to the total count of fungi after 2 days but was regularly significantly toxic at the three doses after 5, 20 and 40 days and toxic at the low and the high doses after 80 days. In the agar medium, it was toxic to the counts of total fungi. Aspergillus, A. terreus, Rhizopus oryzae and Mucor racemosus at the high dose. Only the mycelial growth of Trichoderma viride which was significantly inhibited by the three doses when this fungicide was added to the liquid medium. Polyram-Combi induced two effects on the total population of soil fungi. One inhibitory and this was demonstrated almost regularly after 2, 10 and 40 days and the other stimulatory after 80 days of treatment with the low and the high doses. In the agar medium, this fungicide was very toxic to total fungi and to almost all fungal genera and species at the three doses. Several fungi could survive the high dose. In liquid medium, the test fungi showed variable degree of sensitivity and the most sensitive was Gliocladium roseum which was completely eradicated by the three doses.

Physics considerations in MV-CBCT multi-layer imager design.

PubMed

Hu, Yue-Houng; Fueglistaller, Rony; Myronakis, Marios E; Rottmann, Joerg; Wang, Adam; Shedlock, Daniel; Morf, Daniel; Baturin, Paul; Huber, Pascal; Star-Lack, Josh M; Berbeco, Ross I

2018-05-30

Megavoltage (MV) cone-beam computed tomography (CBCT) using an electronic portal imaging (EPID) offers advantageous features, including 3D mapping, treatment beam registration, high-z artifact suppression, and direct radiation dose calculation. Adoption has been slowed by image quality limitations and concerns about imaging dose. Developments in imager design, including pixelated scintillators, structured phosphors, inexpensive scintillation materials, and multi-layer imager (MLI) architecture have been explored to improve EPID image quality and reduce imaging dose. The present study employs a hybrid Monte Carlo and linear systems model to determine the effect of detector design elements, such as multi-layer architecture and scintillation materials. We follow metrics of image quality including modulation transfer function (MTF) and noise power spectrum (NPS) from projection images to 3D reconstructions to in-plane slices and apply a task based figure-of-merit, the ideal observer signal-to-noise ratio (d') to determine the effect of detector design on object detectability. Generally, detectability was limited by detector noise performance. Deploying an MLI imager with a single scintillation material for all layers yields improvement in noise performance and d' linear with the number of layers. In general, improving x-ray absorption using thicker scintillators results in improved DQE(0). However, if light yield is low, performance will be affected by electronic noise at relatively high doses, resulting in rapid image quality degradation. Maximizing image quality in a heterogenous MLI detector (i.e. multiple different scintillation materials) is most affected by limiting imager noise. However, while a second-order effect, maximizing total spatial resolution of the MLI detector is a balance between the intensity contribution of each layer against its individual MTF. So, while a thinner scintillator may yield a maximal individual-layer MTF, its quantum efficiency will be relatively low in comparison to a thicker scintillator and thus, intensity contribution may be insufficient to noticeably improve the total detector MTF. © 2018 Institute of Physics and Engineering in Medicine.

Effects of photoperiod regimes and ultraviolet-C radiations on biosynthesis of industrially important lignans and neolignans in cell cultures of Linum usitatissimum L. (Flax).

PubMed

Anjum, Sumaira; Abbasi, Bilal Haider; Doussot, Joël; Favre-Réguillon, Alain; Hano, Christophe

2017-02-01

Lignans and neolignans are principal bioactive components of Linum usitatissimum L. (Flax), having multiple pharmacological activities. In present study, we are reporting an authoritative abiotic elicitation strategy of photoperiod regimes along with UV-C radiations. Cell cultures were grown in different photoperiod regimes (24h-dark, 24h-light and 16L/8D h photoperiod) either alone or in combination with various doses (1.8-10.8kJ/m 2 ) of ultraviolet-C (UV-C) radiations. Secoisolariciresinol diglucoside (SDG), lariciresinol diglucoside (LDG), dehydrodiconiferyl alcohol glucoside (DCG), and guaiacylglycerol-β-coniferyl alcohol ether glucoside (GGCG) were quantified by using reverse phase-high performance liquid chromatography (RP-HPLC). Results showed that the cultures exposed to UV-C radiations, accumulated higher levels of lignans, neolignans and other biochemical markers than cultures grown under different photoperiod regimes. 3.6kJ/m 2 dose of UV-C radiations resulted in 1.86-fold (7.1mg/g DW) increase in accumulation of SDG, 2.25-fold (21.6mg/g DW) in LDG, and 1.33-fold (9.2mg/g DW) in GGCG in cell cultures grown under UV+photoperiod than their respective controls. Furthermore, cell cultures grown under UV+dark showed 1.36-fold (60.0mg/g DW) increase in accumulation of DCG in response to 1.8kJ/m 2 dose of UV-C radiations. Smilar trends were observed in productivity of SDG, LDG and GGCG. Additionally, 3.6kJ/m 2 dose of UV-C radiations also resulted in 2.82-fold (195.65mg/l) increase in total phenolic production, 2.94-fold (98.9mg/l) in total flavonoid production and 1.04-fold (95%) in antioxidant activity of cell cultures grown under UV+photoperiod. These findings open new dimensions for feasible production of biologically active lignans and neolignans by Flax cell cultures. Copyright © 2017 Elsevier B.V. All rights reserved.

Total-dose radiation effects data for semiconductor devices: 1985 supplement, volume 1

NASA Technical Reports Server (NTRS)

Martin, K. E.; Gauthier, M. K.; Coss, J. R.; Dantas, A. R. V.; Price, W. E.

1985-01-01

Steady-state, total-dose radiation test data are provided, in graphic format, for use by electronic designers and other personnel using semiconductor devices in a radiation environment. The data were generated by JPL for various NASA space programs. The document is in two volumes: Volume 1 provides data on diodes, bipolar transistors, field effect transistors, and miscellaneous semiconductor types, and Volume 2 provides total-dose radiation test data on integrated circuits. Volume 1 of this 1985 Supplement contains new total-dose radiation test data generated since the August 1, 1981 release date of the original Volume 1. Publication of Volume 2 of the 1985 Supplement will follow that of Volume 1 by approximately three months.

Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases.

PubMed

Welch, David; Buonanno, Manuela; Grilj, Veljko; Shuryak, Igor; Crickmore, Connor; Bigelow, Alan W; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

2018-02-09

Airborne-mediated microbial diseases such as influenza and tuberculosis represent major public health challenges. A direct approach to prevent airborne transmission is inactivation of airborne pathogens, and the airborne antimicrobial potential of UVC ultraviolet light has long been established; however, its widespread use in public settings is limited because conventional UVC light sources are both carcinogenic and cataractogenic. By contrast, we have previously shown that far-UVC light (207-222 nm) efficiently inactivates bacteria without harm to exposed mammalian skin. This is because, due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer (non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or smaller dimensions, far-UVC can penetrate and inactivate them. We show for the first time that far-UVC efficiently inactivates airborne aerosolized viruses, with a very low dose of 2 mJ/cm 2 of 222-nm light inactivating >95% of aerosolized H1N1 influenza virus. Continuous very low dose-rate far-UVC light in indoor public locations is a promising, safe and inexpensive tool to reduce the spread of airborne-mediated microbial diseases.

The interoceptive Pavlovian stimulus effects of caffeine

PubMed Central

Murray, Jennifer E.; Li, Chia; Palmatier, Matthew I.

2007-01-01

The present research sought to test whether caffeine functioned as a Pavlovian cue in two ways—as a positive drug feature or as a conditional stimulus (CS). As a positive feature (Experiment 1), brief light presentations were followed by sucrose only on sessions in which caffeine (10 mg/kg) was administered. On intermixed saline sessions, light presentations were not followed by sucrose. The light came to control robust goal-tracking (i.e., conditioned responding) only in caffeine sessions. Thus, caffeine disambiguates when the light was paired with sucrose. Decreasing the dose of caffeine decreased the conditioned responding evoked by the light (ED50=4.16 mg/kg). Neither nicotine nor amphetamine substituted for the caffeine feature. As a CS, caffeine (10 or 30 mg/kg, Experiments 2a and 2b, respectively) signaled intermittent access to sucrose—no light presentations. No sucrose or lights were presented on intermixed saline sessions. The caffeine CS, regardless of training dose, acquired the ability to evoke only a weak goal-tracking CR. The nature of this dissociation between caffeine as a drug feature versus a CS is discussed within the context of past research finding a similar dissociation with amphetamine and chlordiazepoxide, but not with nicotine. PMID:17477964

Total Ionizing Dose Test Report for the UC1823A Pulse Width Modulator

NASA Technical Reports Server (NTRS)

Chen, Dakai; Forney, James

2017-01-01

The purpose of this study is to examine the total ionizing dose susceptibility for the UC1823A pulse width modulator manufactured by Texas Instruments, Inc. The part is suspected to be vulnerable to enhanced low dose rate sensitivity (ELDRS).

ELDRS Characterization for a Very High Dose Mission

NASA Technical Reports Server (NTRS)

Harris, Richard D.; McClure, Steven S.; Rax, Bernard G.; Kenna, Aaron J.; Thorbourn, Dennis O.; Clark, Karla B.; Yan, Tsun-Yee

2010-01-01

Evaluation of bipolar linear parts which may have Enhanced Low Dose Rate Sensitivity (ELDRS) is problematic for missions that have very high dose radiation requirements. The accepted standards for evaluating parts that display ELDRS require testing at a very low dose rate which could be prohibitively long for very high dose missions. In this work, a methodology for ELDRS characterization of bipolar parts for mission doses up to 1 Mrad(Si) is evaluated. The procedure employs an initial dose rate of 0.01 rad(Si)/s to a total dose of 50 krad(Si) and then changes to 0.04 rad(Si)/s to a total dose of 1 Mrad(Si). This procedure appears to work well. No change in rate of degradation with dose has been observed when the dose rate is changed from 0.01 to 0.04 rad(Si)/s. This is taken as an indication that the degradation due to the higher dose rate is equivalent to that at the lower dose rate at the higher dose levels, at least for the parts studied to date. In several cases, significant parameter degradation or functional failure not observed at HDR was observed at fairly high total doses (50 to 250 krad(Si)) at LDR. This behavior calls into question the use of dose rate trend data and enhancement factors to predict LDR performance.

Characterization of light transmissions in various optical fibers with proton beam

NASA Astrophysics Data System (ADS)

Song, Young Beom; Kim, Hye Jin; Kim, Mingeon; Lee, Bongsoo; Shin, Sang Hun; Yoo, Wook Jae; Jang, Kyoung Won; Hwang, Sung Won

2017-12-01

As a feasibility study on the development of a fiber-optic radiation sensor for proton therapy dosimetry, we characterized light transmissions of various commercial optical fibers such as silica and plastic based optical fibers by the irradiation of proton beams. In this study, we measured light transmission spectra of optical fibers as a function of absorbed doses of proton beams using a deuterium & tungsten halogen lamps and a spectrometer. To be used as a fiber-optic radiation sensor, the optical fibers should have the radiation resistant characteristics and provide stable output signals during the proton beam irradiation. In this study, we could select suitable optical fibers to be used in the fiber-optic radiation sensor without quenching effects for proton therapy dosimetry. As a result, the light transmittance of the optical fibers had decreasing trends with increasing absorbed dose as expected.

A thermo-degradable hydrogel with light-tunable degradation and drug release.

PubMed

Hu, Jingjing; Chen, Yihua; Li, Yunqi; Zhou, Zhengjie; Cheng, Yiyun

2017-01-01

The development of thermo-degradable hydrogels is of great importance in drug delivery. However, it still remains a huge challenge to prepare thermo-degradable hydrogels with inherent degradation, reproducible, repeated and tunable dosing. Here, we reported a thermo-degradable hydrogel that is rapidly degraded above 44 °C by a facile chemistry. Besides thermo-degradability, the hydrogel also undergoes rapid photolysis with ultraviolet light. By embedding photothermal nanoparticles or upconversion nanoparticles into the gel, it can release the entrapped cargoes such as dyes, enzymes and anticancer drugs in an on-demand and dose-tunable fashion upon near-infrared light exposure. The smart hydrogel works well both in vitro and in vivo without involving sophisticated syntheses, and is well suited for clinical cancer therapy due to the high transparency and non-invasiveness features of near-infrared light. Copyright © 2016 Elsevier Ltd. All rights reserved.

Low-energy electron effects on tensile modulus and infrared transmission properties of a polypyromellitimide film

NASA Technical Reports Server (NTRS)

Ferl, J. E.; Long, E. R., Jr.

1981-01-01

Infrared (IR) spectroscopy and tensile modulus testing were used to evaluate the importance of experimental procedure on changes in properties of pyromellitic dianhydride-p,p prime-oxydianiline film exposed to electron radiation. The radiation exposures were accelerated, approximate equivalents to the total dose expected for a 30 year mission in geosynchronous Earth orbit. The change in the tensile modulus depends more on the dose rate and the time interval between exposure and testing than on total dose. The IR data vary with both total dose and dose rate. A threshold dose rate exists below which reversible radiation effects on the IR spectra occur. Above the threshold dose rate, irreversible effects occur with the appearance of a new band. Post-irradiation and in situ IR absorption bands are significantly different. It is suggested that the electron radiation induced metastable, excites molecular states.

Electrowetting-actuated optical switch based on total internal reflection.

PubMed

Liu, Chao; Wang, Di; Yao, Li-Xiao; Li, Lei; Wang, Qiong-Hua

2015-04-01

In this paper we demonstrate a liquid optical switch based on total internal reflection. Two indium tin oxide electrodes are fabricated on the bottom substrate. A conductive liquid (Liquid 1) is placed on one side of the chamber and surrounded by a density-matched silicone oil (Liquid 2). In initial state, when the light beam illuminates the interface of the two liquids, it just meets the conditions of total internal reflection. The light is totally reflected by Liquid 2, and the device shows light-off state. When we apply a voltage to the other side of the indium tin oxide electrode, Liquid 1 stretched towards this side of the substrate and the curvature of the liquid-liquid interface changes. The light beam is refracted by Liquid 1 and the device shows light-on state. So the device can achieve the functions of an optical switch. Because the light beam can be totally reflected by the liquid, the device can attain 100% light intensity attenuation. Our experiments show that the response time from light-on (off) to light-off (on) are 130 and 132 ms, respectively. The proposed optical switch has potential applications in variable optical attenuators, information displays, and light shutters.

Docetaxel chronopharmacology in mice.

PubMed

Tampellini, M; Filipski, E; Liu, X H; Lemaigre, G; Li, X M; Vrignaud, P; François, E; Bissery, M C; Lévi, F

1998-09-01

Docetaxel tolerance and antitumor efficacy could be enhanced if drug administration was adapted to circadian rhythms. This hypothesis was investigated in seven experiments involving a total of 626 male B6D2F1 mice, synchronized with an alternation of 12 h of light and 12 h of darkness (12:12), after i.v. administration of docetaxel. In experiment (Exp) 1, the drug was given once a week (wk) for 6 wks (20 mg/kg/wk) or for 5 wks (30 mg/kg/wk) at one of six circadian times, during light when mice were resting [3, 7, or 11 hours after light onset (HALO)], or during darkness, when mice were active (15, 19, or 23 HALO). Endpoints were survival and body weight change. In Exp 2 and 3, docetaxel (30 mg/kg/wk) was administered twice, 1 wk apart, at one of four circadian stages (7, 11, 19, or 23 HALO). Endpoints were hematological and intestinal toxicities. In Exp 4, circadian changes in cell cycle phase distribution and BCL-2 immunofluorescence were investigated in bone marrow as possible mechanisms of docetaxel tolerability rhythm. In Exp 5 to 7, docetaxel was administered to mice bearing measurable P03 pancreatic adenocarcinoma (270-370 mg), with tumor weight and survival as endpoints. Mice from Exp 5 and 6 received a weekly schedule of docetaxel at one of six circadian stages (20 or 30 mg/kg/wk at 3, 7, 11, 15, 19, or 23 HALO). In Exp 7, docetaxel (30 mg/kg) was given every 2 days (day 1, 3, 5 schedule) at 7, 11, 19, or 23 HALO. Docetaxel dosing in the second half of darkness (19 or 23 HALO) resulted in significantly worse toxicity than its administration during the light span (3, 7, or 11 HALO). The survival rate ranged from 56.3% in the mice treated at 23 HALO to 93.8 or 87.5% in those injected at 3 or 11 HALO, respectively (Exp 1, P < 0.01). Granulocytopenia at nadir was -49 +/- 14% at 7 HALO compared with -84 +/- 3% at 19 HALO (Exp 2 and 3, P < 0.029), and severe jejunal mucosa necrosis occurred in 5 of 8 mice treated at 23 HALO as opposed to 2 of 18 receiving docetaxel at 7, 11, or 19 HALO (Exp 2 and 3, P < 0.02). The time of least docetaxel toxicity corresponded to the circadian nadir in S or G2-M phase and to the circadian maximum in BCL-2 immunofluorescence in bone marrow. Docetaxel increased the median survival of tumor-bearing mice in a dose-dependent manner (controls: 24 days; 20 mg/kg weekly, 33 days; 30 mg/kg weekly or day 1, 3, 5 schedule, 44 or 46 days, respectively; Exp 5-7). Survival curves of treated mice differed significantly according to dosing time for each dose and schedule (P from log rank <0.003 to P < 0.03). In Exp 5 and 6, the percentage of increase in life span was largest if docetaxel was administered weekly at 7 HALO (20 mg/kg, 220%; 30 mg/kg, 372%) and lowest after docetaxel dosing at 19 HALO (80% with 20 mg/kg) or at 15 HALO (78% with 30 mg/kg). In Exp 7, (day 1, 3, 5 schedule), docetaxel was most active at 11 HALO (percentage increase in life span, 390%) and least active at 23 HALO (210%). Docetaxel tolerability and antitumor efficacy were simultaneously enhanced by drug dosing in the light span, when mice were resting. Mechanisms underlying the tolerability rhythm likely involved the circadian organization of cell cycle regulation. Docetaxel therapeutic index may be improved with an administration at night in cancer patients, when fewest bone marrow cells are in S or G2-M phase.

Near Infrared Photoimmunotherapy Targeting EGFR Positive Triple Negative Breast Cancer: Optimizing the Conjugate-Light Regimen

PubMed Central

Nagaya, Tadanobu; Sato, Kazuhide; Harada, Toshiko; Nakamura, Yuko; Choyke, Peter L.; Kobayashi, Hisataka

2015-01-01

Aim Triple-negative breast cancer (TNBC) is considered one of the most aggressive subtypes of breast cancer. Near infrared photoimmunotherapy (NIR-PIT) is a cancer treatment that employs an antibody-photosensitizer conjugate (APC) followed by exposure of NIR light for activating selective cytotoxicity on targeted cancer cells and may have application to TNBC. In order to minimize the dose of APC while maximizing the therapeutic effects, dosing of the APC and NIR light need to be optimized. In this study, we investigate in vitro and in vivo efficacy of cetuximab (cet)-IR700 NIR-PIT on two breast cancer models MDAMB231 (TNBC, EGFR moderate) and MDAMB468 (TNBC, EGFR high) cell lines, and demonstrate a method to optimize the dosing APC and NIR light. Method After validating in vitro cell-specific cytotoxicity, NIR-PIT therapeutic effects were investigated in mouse models using cell lines derived from TNBC tumors. Tumor-bearing mice were separated into 4 groups for the following treatments: (1) no treatment (control); (2) 300 μg of cet-IR700 i.v., (APC i.v. only); (3) NIR light exposure only, NIR light was administered at 50 J/cm2 on day 1 and 100 J/cm2 on day 2 (NIR light only); (4) 300 μg of cet-IR700 i.v., NIR light was administered at 50 J/cm2 on day 1 after injection and 100 J/cm2 of light on day 2 after injection (one shot NIR-PIT). To compare different treatment regimens with a fixed dose of APC, we added the following treatments (5) 100 μg of cet-IR700 i.v., NIR light administered at 50 J/cm2 on day 1 and 50 μg of cet-IR700 i.v. immediately after NIR-PIT, then NIR light was administered at 100 J/cm2 on day 2, which were performed two times every week (“two split” NIR-PIT) and (6) 100 μg of cet-IR700 i.v., NIR light was administered at 50 J/cm2 on day 1 and 100 J/cm2 on day 2, which were performed three times per week (“three split” NIR-PIT). Result Both specific binding and NIR-PIT effects were greater with MDAMB468 than MDAMB231 cells in vitro. Tumor accumulation of cet-IR700 in MDAMB468 tumors was significantly higher (p < 0.05) than in MDAMB231 tumors in vivo. Tumor growth and survival of MDAMB231 tumor bearing mice was significantly lower in the NIR-PIT treatment group (p < 0.05). In MDAMB468 bearing mice, tumor growth and survival was significantly improved in the NIR-PIT treatment groups in all treatment regimens (one shot NIR-PIT; p < 0.05, “two split” NIR-PIT; p < 0.01, “three split” NIR-PIT; p < 0.001) compared with control groups. Conclusion NIR-PIT for TNBC was effective regardless of expression of EGFR, however, greater cell killing was shown with higher EGFR expression tumor in vitro. In all treatment regimens, NIR-PIT suppressed tumor growth, resulting in significantly prolonged survival that further improved by splitting the APC dose and using repeated light exposures. PMID:26313651

Near Infrared Photoimmunotherapy Targeting EGFR Positive Triple Negative Breast Cancer: Optimizing the Conjugate-Light Regimen.

PubMed

Nagaya, Tadanobu; Sato, Kazuhide; Harada, Toshiko; Nakamura, Yuko; Choyke, Peter L; Kobayashi, Hisataka

2015-01-01

Triple-negative breast cancer (TNBC) is considered one of the most aggressive subtypes of breast cancer. Near infrared photoimmunotherapy (NIR-PIT) is a cancer treatment that employs an antibody-photosensitizer conjugate (APC) followed by exposure of NIR light for activating selective cytotoxicity on targeted cancer cells and may have application to TNBC. In order to minimize the dose of APC while maximizing the therapeutic effects, dosing of the APC and NIR light need to be optimized. In this study, we investigate in vitro and in vivo efficacy of cetuximab (cet)-IR700 NIR-PIT on two breast cancer models MDAMB231 (TNBC, EGFR moderate) and MDAMB468 (TNBC, EGFR high) cell lines, and demonstrate a method to optimize the dosing APC and NIR light. After validating in vitro cell-specific cytotoxicity, NIR-PIT therapeutic effects were investigated in mouse models using cell lines derived from TNBC tumors. Tumor-bearing mice were separated into 4 groups for the following treatments: (1) no treatment (control); (2) 300 μg of cet-IR700 i.v., (APC i.v. only); (3) NIR light exposure only, NIR light was administered at 50 J/cm2 on day 1 and 100 J/cm2 on day 2 (NIR light only); (4) 300 μg of cet-IR700 i.v., NIR light was administered at 50 J/cm2 on day 1 after injection and 100 J/cm2 of light on day 2 after injection (one shot NIR-PIT). To compare different treatment regimens with a fixed dose of APC, we added the following treatments (5) 100 μg of cet-IR700 i.v., NIR light administered at 50 J/cm2 on day 1 and 50 μg of cet-IR700 i.v. immediately after NIR-PIT, then NIR light was administered at 100 J/cm2 on day 2, which were performed two times every week ("two split" NIR-PIT) and (6) 100 μg of cet-IR700 i.v., NIR light was administered at 50 J/cm2 on day 1 and 100 J/cm2 on day 2, which were performed three times per week ("three split" NIR-PIT). Both specific binding and NIR-PIT effects were greater with MDAMB468 than MDAMB231 cells in vitro. Tumor accumulation of cet-IR700 in MDAMB468 tumors was significantly higher (p < 0.05) than in MDAMB231 tumors in vivo. Tumor growth and survival of MDAMB231 tumor bearing mice was significantly lower in the NIR-PIT treatment group (p < 0.05). In MDAMB468 bearing mice, tumor growth and survival was significantly improved in the NIR-PIT treatment groups in all treatment regimens (one shot NIR-PIT; p < 0.05, "two split" NIR-PIT; p < 0.01, "three split" NIR-PIT; p < 0.001) compared with control groups. NIR-PIT for TNBC was effective regardless of expression of EGFR, however, greater cell killing was shown with higher EGFR expression tumor in vitro. In all treatment regimens, NIR-PIT suppressed tumor growth, resulting in significantly prolonged survival that further improved by splitting the APC dose and using repeated light exposures.

Lung dosimetry for inhaled radon progeny in smokers.

PubMed

Baias, Paul F; Hofmann, Werner; Winkler-Heil, Renate; Cosma, Constantin; Duliu, Octavian G

2010-02-01

Cigarette smoking may change the morphological and physiological parameters of the lung. Thus the primary objective of the present study was to investigate to what extent these smoke-induced changes can modify deposition, clearance and resulting doses of inhaled radon progeny relative to healthy non-smokers (NSs). Doses to sensitive bronchial target cells were computed for four categories of smokers: (1) Light, short-term (LST) smokers, (2) light, long-term (LLT) smokers, (3) heavy, short-term (HST) smokers and (4) heavy, long-term (HLT) smokers. Because of only small changes of morphological and physiological parameters, doses for the LST smokers hardly differed from those for NSs. For LLT and HST smokers, even a protective effect could be observed, caused by a thicker mucus layer and increased mucus velocities. Only in the case of HLT smokers were doses higher by about a factor of 2 than those for NSs, caused primarily by impaired mucociliary clearance, higher breathing frequency, reduced lung volume and airway obstructions. These higher doses suggest that the contribution of inhaled radon progeny to the risk of lung cancer in smokers may be higher than currently assumed on the basis of NS doses.

Enhancement of phototropic response to a range of light doses in Triticum aestivum coleoptiles in clinostat-simulated microgravity

NASA Technical Reports Server (NTRS)

Heathcote, D. G.; Bircher, B. W.; Brown, A. H. (Principal Investigator)

1987-01-01

The phototropic dose-response relationship has been determined for Triticum aestivum cv. Broom coleoptiles growing on a purpose-built clinostat apparatus providing gravity compensation by rotation about a horizontal axis at 2 rev min-1. These data are compared with data sets obtained with the clinostat axis vertical and stationary, as a 1 g control, and rotating vertically to examine clinostat effects other than gravity compensation. Triticum at 1 g follows the well-established pattern of other cereal coleoptiles with a first positive curvature at low doses, followed by an indifferent response region, and a second positive response at progressively increasing doses. However, these response regions lie at higher dose levels than reported for Avena. There is no significant difference between the responses observed with the clinostat axis vertical in the rotating and stationary modes, but gravity compensation by horizontal rotation increases the magnitude of first and second positive curvatures some threefold at 100 min after stimulation. The indifferent response is replaced by a significant curvature towards the light source, but remains apparent as a reduced curvature response at these dose levels.

On the origin of the visible light responsible for proton dose measurement using plastic optical fibers

NASA Astrophysics Data System (ADS)

Darafsheh, Arash; Taleei, Reza; Kassaee, Alireza; Finlay, Jarod C.

2017-03-01

We experimentally and by means of Monte Carlo simulations investigated the origin of the visible signal responsible for proton therapy dose measurement using bare plastic optical fibers. Experimentally, the fiber optic probe, embedded in tissue-mimicking plastics, was irradiated with a proton beam produced by a proton therapy cyclotron and the luminescence spectroscopy was performed by a CCD-coupled spectrograph to analyze the emission spectrum of the fiber tip. Monte Carlo simulations were performed using FLUKA Monte Carlo code to stochastically simulate radiation transport, ionizing radiation dose deposition, and optical emission of Čerenkov radiation. The spectroscopic study of proton-irradiated plastic fibers showed a continuous spectrum with shape different from that of Čerenkov radiation. The Monte Carlo simulations confirmed that the amount of the generated Čerenkov light does not follow the radiation absorbed dose in a medium. Our results show that the origin of the optical signal responsible for the proton dose measurement using bare optical fibers is not Čerenkov radiation. Our results point toward a connection between the scintillation of the plastic material of the fiber and the origin of the signal responsible for dose measurement.

Effect of peracetic acid, ultraviolet radiation, nanofiltration-chlorine in the disinfection of a non conventional source of water (Tula Valley).

PubMed

Trujillo, J; Barrios, J A; Jimenez, B

2008-01-01

Water supply for human consumption requires certain quality that reduces health risks to consumers. In this sense, the process of disinfection plays an important role in the elimination of pathogenic microorganisms. Even though chlorination is the most applied process based on its effectiveness and cost, its application is being questioned considering the formation of disinfection by-products (DBPs). Therefore, alternative disinfectants are being evaluated and some treatment processes have been proposed to remove DBPs precursors (organic matter. This paper reports the results of disinfection of a non conventional source of water (aquifer recharged unintentionally with raw wastewater) with peracetic acid (PAA) and ultraviolet radiation (UV) as well as nanofiltration (NF) followed by chlorination to produce safe drinking water. The results showed that a dose of 2 mg/L PAA was needed to eliminate total and faecal coliforms. For UV light, a dose of 12.40 mWs/cm2 reduced total and faecal coliforms below the detection limit. On the other hand, chlorine demand of water before NF was 1.1-1.3 mg/L with a trihalomethane formation potential (THMFP) of 118.62 microg/L, in contrast with chlorination after NF where the demand was 0.5 mg/L and THMFP of 17.64 microg/L. The recommended scheme is nanofiltration + chlorination.

Fast-to-slow shift of muscle fiber-type composition by dietary apple polyphenols in rats: Impact of the low-dose supplementation.

PubMed

Mizunoya, Wataru; Okamoto, Shinpei; Miyahara, Hideo; Akahoshi, Mariko; Suzuki, Takahiro; Do, Mai-Khoi Q; Ohtsubo, Hideaki; Komiya, Yusuke; Qahar, Mulan; Waga, Toshiaki; Nakazato, Koichi; Ikeuchi, Yoshihide; Anderson, Judy E; Tatsumi, Ryuichi

2017-03-01

Our previous studies demonstrated that an 8-week intake of 5% (w/w) apple polyphenol (APP) in the diet improves muscle endurance of young-adult rats. In order to identify a lower limit of the dietary contribution of APP to the effect, the experiments were designed for lower-dose supplementation (8-week feeding of 0.5% APP in AIN-93G diet) to 12-week-old male Sprague-Dawley rats. Results clearly showed that the 0.5% APP diet significantly up-regulates slower myosin-heavy-chain (MyHC) isoform ratios (IIx and IIa relative to total MyHC) and myoglobin expression in lower hind-limb muscles examined (P < 0.05). There was a trend to increased fatigue resistance detected from measurements of relative isometric plantar-flexion force torque generated by a stimulus train delivered to the tibial nerve (F(98, 1372) = 1.246, P = 0.0574). Importantly, there was no significant difference in the animal body-phenotypes or locomotor activity shown as total moving distance in light and dark periods. Therefore, the present study encourages the notion that even low APP-intake may increase the proportions of fatigue-resistant myofibers, and has promise as a strategy for modifying performance in human sports and improving function in age-related muscle atrophy. © 2016 Japanese Society of Animal Science.

Can gamma irradiation during radiotherapy influence the metal release process for biomedical CoCrMo and 316L alloys?

PubMed

Wei, Zheng; Edin, Jonathan; Karlsson, Anna Emelie; Petrovic, Katarina; Soroka, Inna L; Odnevall Wallinder, Inger; Hedberg, Yolanda

2018-02-09

The extent of metal release from implant materials that are irradiated during radiotherapy may be influenced by irradiation-formed radicals. The influence of gamma irradiation, with a total dose of relevance for radiotherapy (e.g., for cancer treatments) on the extent of metal release from biomedical stainless steel AISI 316L and a cobalt-chromium alloy (CoCrMo) was investigated in physiological relevant solutions (phosphate buffered saline with and without 10 g/L bovine serum albumin) at pH 7.3. Directly after irradiation, the released amounts of metals were significantly higher for irradiated CoCrMo as compared to nonirradiated CoCrMo, resulting in an increased surface passivation (enhanced passive conditions) that hindered further release. A similar effect was observed for 316L showing lower nickel release after 1 h of initially irradiated samples as compared to nonirradiated samples. However, the effect of irradiation (total dose of 16.5 Gy) on metal release and surface oxide composition and thickness was generally small. Most metals were released initially (within seconds) upon immersion from CoCrMo but not from 316L. Albumin induced an increased amount of released metals from AISI 316L but not from CoCrMo. Albumin was not found to aggregate to any greater extent either upon gamma irradiation or in the presence of trace metal ions, as determined using different light scattering techniques. Further studies should elucidate the effect of repeated friction and fractionated low irradiation doses on the short- and long term metal release process of biomedical materials. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018. © 2018 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc.

A comprehensive study on the relationship between the image quality and imaging dose in low-dose cone beam CT

NASA Astrophysics Data System (ADS)

Yan, Hao; Cervino, Laura; Jia, Xun; Jiang, Steve B.

2012-04-01

While compressed sensing (CS)-based algorithms have been developed for the low-dose cone beam CT (CBCT) reconstruction, a clear understanding of the relationship between the image quality and imaging dose at low-dose levels is needed. In this paper, we qualitatively investigate this subject in a comprehensive manner with extensive experimental and simulation studies. The basic idea is to plot both the image quality and imaging dose together as functions of the number of projections and mAs per projection over the whole clinically relevant range. On this basis, a clear understanding of the tradeoff between the image quality and imaging dose can be achieved and optimal low-dose CBCT scan protocols can be developed to maximize the dose reduction while minimizing the image quality loss for various imaging tasks in image-guided radiation therapy (IGRT). Main findings of this work include (1) under the CS-based reconstruction framework, image quality has little degradation over a large range of dose variation. Image quality degradation becomes evident when the imaging dose (approximated with the x-ray tube load) is decreased below 100 total mAs. An imaging dose lower than 40 total mAs leads to a dramatic image degradation, and thus should be used cautiously. Optimal low-dose CBCT scan protocols likely fall in the dose range of 40-100 total mAs, depending on the specific IGRT applications. (2) Among different scan protocols at a constant low-dose level, the super sparse-view reconstruction with the projection number less than 50 is the most challenging case, even with strong regularization. Better image quality can be acquired with low mAs protocols. (3) The optimal scan protocol is the combination of a medium number of projections and a medium level of mAs/view. This is more evident when the dose is around 72.8 total mAs or below and when the ROI is a low-contrast or high-resolution object. Based on our results, the optimal number of projections is around 90 to 120. (4) The clinically acceptable lowest imaging dose level is task dependent. In our study, 72.8 mAs is a safe dose level for visualizing low-contrast objects, while 12.2 total mAs is sufficient for detecting high-contrast objects of diameter greater than 3 mm.

Comparison of patient specific dose metrics between chest radiography, tomosynthesis, and CT for adult patients of wide ranging body habitus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yakun; Li, Xiang; Segars, W. Paul

2014-02-15

Purpose: Given the radiation concerns inherent to the x-ray modalities, accurately estimating the radiation doses that patients receive during different imaging modalities is crucial. This study estimated organ doses, effective doses, and risk indices for the three clinical chest x-ray imaging techniques (chest radiography, tomosynthesis, and CT) using 59 anatomically variable voxelized phantoms and Monte Carlo simulation methods. Methods: A total of 59 computational anthropomorphic male and female extended cardiac-torso (XCAT) adult phantoms were used in this study. Organ doses and effective doses were estimated for a clinical radiography system with the capability of conducting chest radiography and tomosynthesis (Definiummore » 8000, VolumeRAD, GE Healthcare) and a clinical CT system (LightSpeed VCT, GE Healthcare). A Monte Carlo dose simulation program (PENELOPE, version 2006, Universitat de Barcelona, Spain) was used to mimic these two clinical systems. The Duke University (Durham, NC) technique charts were used to determine the clinical techniques for the radiographic modalities. An exponential relationship between CTDI{sub vol} and patient diameter was used to determine the absolute dose values for CT. The simulations of the two clinical systems compute organ and tissue doses, which were then used to calculate effective dose and risk index. The calculation of the two dose metrics used the tissue weighting factors from ICRP Publication 103 and BEIR VII report. Results: The average effective dose of the chest posteroanterior examination was found to be 0.04 mSv, which was 1.3% that of the chest CT examination. The average effective dose of the chest tomosynthesis examination was found to be about ten times that of the chest posteroanterior examination and about 12% that of the chest CT examination. With increasing patient average chest diameter, both the effective dose and risk index for CT increased considerably in an exponential fashion, while these two dose metrics only increased slightly for radiographic modalities and for chest tomosynthesis. Effective and organ doses normalized to mAs all illustrated an exponential decrease with increasing patient size. As a surface organ, breast doses had less correlation with body size than that of lungs or liver. Conclusions: Patient body size has a much greater impact on radiation dose of chest CT examinations than chest radiography and tomosynthesis. The size of a patient should be considered when choosing the best thoracic imaging modality.« less

Decorporation Approach after Rat Lung Contamination with Plutonium: Evaluation of the Key Parameters Influencing the Efficacy of a Protracted Chelation Treatment.

PubMed

Grémy, Olivier; Coudert, Sylvie; Renault, Daniel; Miccoli, Laurent

2017-11-01

While the efficacy of a protracted zinc (Zn)- or calcium (Ca)-diethylenetriaminepentaacetic acid (DTPA) treatment in reducing transuranic body burden has already been demonstrated, questions about therapeutic variables remain. In response to this, we designed animal experiments primarily to assess both the effect of fractionation of a given dose and the effect of the frequency of dose fraction, with the same total dose. In our study, rats were contaminated intravenously with plutonium (Pu) then treated several days later with Ca-DTPA given at once or in various split-dose regimens cumulating to the same total dose and spread over several days. Similar efficacies were induced by the injection of the total dose or by splitting the dose in several smaller doses, independent of the number of doses and the dose level per injection. In a second study, rats were pulmonary contaminated, and three weeks later they received a Ca-DTPA dose 11-fold higher than the maximal daily recommended dose, administered either as a single bolus or as numerous multiple injections cumulating to the same dose, based on different injection frequency schedules. Independent of frequency schedule, the various split-dose regimens spread over weeks/months were as efficient as single delivery of the total dose in mobilizing lung plutonium, and had a therapeutic advantage for removal of retained hepatic and bone plutonium burdens. We concluded that cumulative dose level was a therapeutic variable of greater importance than the distribution of split doses for the success of a repeated treatment regimen on retained tissue plutonium. In addition, pulmonary administration of clodronate, which aims at killing alveolar macrophages and subsequently releasing their plutonium content, and which is associated with a continuous Ca-DTPA infusion regimen, suggested that the efficacy of injected Ca-DTPA in decorporating lung deposit is limited, due to its restricted penetration into alveolar macrophages and not because plutonium, as a physicochemical form, is unavailable for chelation.

[Prevention of adriamycin-induced alopecia by scalp hypothermia with a deep-frozen Duncool-Cap].

PubMed

Konishi, Y; Kuroki, T

1988-11-01

In order to prevent Adriamycin (ADM)-induced alopecia, scalp hypothermia with a Duncool-Cap frozen in a freezer at -70 degrees C was carried out. Of the 18 patients studied, one patient given total ADM doses of 240 mg developed alopecia of moderate degree, and another patient treated with ADM at a dose level of 50 mg developed mild alopecia. Alopecia could be almost completely prevented in 10 of the 11 patients given total ADM doses of 100 mg or less, and in 6 of the 7 patients given total doses of 200 mg or more.

Comparison of different glucocorticoid regimens in the management of classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

PubMed

Ajish, T P; Praveen, V P; Nisha, B; Kumar, Harish

2014-11-01

There are recommendations regarding the total dose of hydrocortisone to be administered in the treatment of classical congenital adrenal hyperplasia (CAH) to achieve the twin objectives of glucocorticoid replacement and control of hyperandrogenism. However, there is evidence gap regarding the breakup, timing and type of the steroid regimen. Efficacy of three different glucocorticoid regimens having the same total dose of steroid, differing in either the timing or type of evening steroid administered, in achieving biochemical control of the disease was assessed. The study was done in 13 prepubertal children with classical CAH over a 6-month period with 2 months devoted to each regimen. We used a prospective cross-over design using 10-15 mg/m(2) total dose of hydrocortisone. Two-fifths of the total dose of hydrocortisone was administered in the morning and one-fifth of the total dose was administered at noon in all the regimens. The regimens differed in the timing of the evening dose of hydrocortisone, 06.00-07.00 pm in regimen 1 and 09.00-10.00 pm in regimen 2. The third regimen had the evening dose of hydrocortisone replaced by an equivalent dose of prednisolone suspension which was administered at 10.00 pm. Serum 17-hydroxyprogesterone and testosterone levels were compared to assess the efficacy of treatment regimens. The three different regimens were found to be similar in their ability to control 17-hydroxyprogesterone and testosterone levels. The percentage of patients with predefined criteria for biochemically controlled disease was similar in all the three regimens. However, there was a trend toward better control of 17-hydroxyprogesterone levels in patients receiving evening dose of prednisolone. There is no significant advantage in administering the hydrocortisone dose late at night in patients with classical CAH.

Optically Stimulated Luminescence (OSL) of Tooth Enamel and its Potential Use in Post-Radiation Exposure Triage

PubMed Central

DeWitt, R.; Klein, D. M.; Yukihara, E. G.; Simon, S. L.; McKeever, S. W. S.

2009-01-01

Optically stimulated luminescence (OSL) properties of dental enamel are discussed with a view to the development of an in-vivo dose assessment technique for medical triage following a radiological/nuclear accident or terrorist event. In the OSL technique, past radiation exposure is assessed by stimulating the sample with light of one wavelength and monitoring the luminescence at another wavelength under the assumption that the luminescence originates from the recombination of radiation-induced charges trapped at metastable defects in the enamel and that the intensity of the luminescence signal is in proportion to the absorbed radiation dose. Several primary findings emerged from this research: (a) sensitivities varied considerably between different teeth and also between fragments of the same tooth, (b) OSL signals were found to decay rapidly during the first 12 hours after irradiation and slower afterwards, (c) the fading rate of the luminescence signal varied between fragments, (d) blue light stimulation yields greater sensitivity than infra-red stimulation, while the OSL signal obtained with a high-intensity pulsed green-light laser was found to be not correlated with the radiation dose. Significant challenges remain to developing a practical in-vivo technique including the development of calibration procedures and lowering minimum detectable doses. PMID:20065717

Comparison of the antinociceptive action of crude Fuzei, the root of Aconitum, and its processed products.

PubMed

Liou, Shorong-Shii; Liu, I-Min; Lai, Mei Chou; Cheng, Juei-Tang

2005-07-14

The antinociceptive effects of crude Fuzei, the root of Aconitum carmichaeli and of Fuzei processed by three different methods were determined in mice and rats using the light tail-flick assay. A dose-dependent and significant increase in pain threshold was found at 60 min post treatment, with doses of 20-60 mg/kg crude Fuzei. The analgesic effects of processed Fuzei (20-60 mg/kg) exhibited a dose-dependent inhibition of tail-flick, but the effects were lower than those produced by crude Fuzei in the same tests. The analgesic effect of Yan-Fuzei, the salt baking product, was the most potent of the processed products and was nearly that provided by crude Fuzei. Although the concentrations of aconitine were significantly lower in the processed Fuzei than in the crude Fuzei, a higher oral LD50 was found for all of the processed Fuzei formulations. Moreover, antinociception of crude Fuzei and its processed products was attenuated but not totally blocked by naloxone at doses sufficient to block opioid mu-receptors. Furthermore, the analgesic effect of crude Fuzei and its processed products was decreased in opioid mu-receptor knockout mice, but the effect remained unaltered in mice with opioid mu-receptors, indicating that the analgesic effect of Fuzei is centrally mediated. These results demonstrate that Fuzei processed by salt baking possesses analgesic effects within a large therapeutic range, probably via a mechanism involving central opioid receptors that mediate the antinociception.

Long-term erythemal UV doses at Sodankylä estimated using total ozone, sunshine duration and snow depth

NASA Astrophysics Data System (ADS)

Lindfors, A. V.; Arola, A.; Kaurola, J.; Taalas, P.; Svenøe, T.

2003-04-01

A method for estimating daily erythemal UV doses using total ozone, sunshine duration and snow depth has been developed. The method consists of three steps: (1) daily clear-sky UV doses were simulated using the UVSPEC radiative transfer program, with daily values of total ozone as input data, (2) an empirical relationship was sought between the simulated clear-sky UV doses, the measured UV doses and the duration of bright sunshine, (3) daily erythemal UV doses were estimated using this relationship. The method accounts for the varying surface albedo by dividing the period of interest into winter and summer days, depending on the snow depth. Using this method, the daily erythemal UV doses at Sodankylä were estimated for the period 1950--99. This was done using Tromsø's total ozone together with Sodankylä's own sunshine duration and snow depth as input data. Although the method is fairly simple, the results are in good agreement, even on the daily scale, with the UV radiation measured with the Brewer spectrophotometer at Sodankylä. Statistically significant increasing trends in erythemal UV doses of a few percents per decade over the period 1950--99 were found for March and April, suggesting a connection to the stratospheric ozone depletion. For July, on the other hand, a significant decreasing trend of about 3% per decade, supported by the changes in both total ozone and sunshine duration, was found. The produced data set of erythemal UV doses is the longest time series of estimated UV known to the authors.

The Impact of Dose Rate on the Accuracy of Step-and-Shoot Intensity-modulated Radiation Therapy Quality Assurance Using Varian 2300CD.

PubMed

Njeh, Christopher F; Salmon, Howard W; Schiller, Claire

2017-01-01

Intensity-modulated radiation therapy (IMRT) delivery using "step-and-shoot" technique on Varian C-Series linear accelerator (linac) is influenced by the communication frequency between the multileaf collimator and linac controllers. Hence, the dose delivery accuracy is affected by the dose rate. Our aim was to quantify the impact of using two dose rates on plan quality assurance (QA). Twenty IMRT patients were selected for this study. The plan QA was measured at two different dose rates. A gamma analysis was performed, and the degree of plan modulation on the QA pass rate was also evaluated in terms of average monitor unit per segment (MU/segment) and the total number of segments. The mean percentage gamma pass rate of 94.9% and 93.5% for 300 MU/min and 600 MU/min dose rate, respectively, was observed. There was a significant ( P = 0.001) decrease in percentage gamma pass rate when the dose rate was increased from 300 MU/min to 600 MU/min. There was a weak, but significant association between the percentage pass rate at both dose rate and total number of segments. The total number of MU was significantly correlated to the total number of segments ( r = 0.59). We found a positive correlation between the percentage pass rate and mean MU/segment, r = 0.52 and r = 0.57 for 300 MU/min and 600 MU/min, respectively. IMRT delivery using step-and-shoot technique on Varian 2300CD is impacted by the dose rate and the total amount of segments.

Confidence Level Based Approach to Total Dose Specification for Spacecraft Electronics

NASA Technical Reports Server (NTRS)

Xapsos, M. A.; Stauffer, C.; Phan, A.; McClure, S. S.; Ladbury, R. L.; Pellish, J. A.; Campola, M. J.; Label, K. A.

2017-01-01

A confidence level based approach to total dose radiation hardness assurance is presented for spacecraft electronics. It is applicable to both ionizing and displacement damage dose. Results are compared to the traditional approach that uses radiation design margin and advantages of the new approach are discussed.

Total Ionizing Dose Effects in Bipolar and BiCMOS Devices

NASA Technical Reports Server (NTRS)

Chavez, Rosa M.; Rax, Bernard G.; Scheick, Leif Z.; Johnston, Allan H.

2005-01-01

This paper describes total ionizing dose (TID) test results performed at JPL. Bipolar and BiCMOS device samples were tested exhibiting significant degradation and failures at different irradiation levels. Linear technology which is susceptible to low-dose dependency (ELDRS) exhibited greater damage for devices tested under zero bias condition.

Human Erythropoietin Effect in Postoperative Visual Loss Following Spine Surgery: A Case Report

PubMed Central

Hassani, Valiollah; Homaei, Mohammad Mohsen; Shahbazi, Ali; Zamani, Mohammad Mahdi; Safari, Saeid; Nadi, Shermila; Rahimizadeh, Abolfazl; Lashkari, Mohammad Hossein; Alizadeh zendehrood, Siamak

2014-01-01

Introduction: Postoperative visual loss (POVL) has become the focus of attention for anesthesiologists as a hallmark of perioperative management in spine surgery. A number of Intraoperative and postoperative factors has been documented but the exact etiology is still unclear. Nowadays, perioperative management and also complete curing of POLV is a big question of ophthalmologists and anesthesiologists. The purpose of this case report is to present a unique experience of complete curing the POLV. Case Presentation: Our patient was a 61-year-old man, with 75 kg weight and 180 cm height. The patient had no history of visual impairment except mild cataract in his right eye. The patient had a history of diffuse idiopathic skeletal hyperostosis (DISH). The patient had undergone lumbar surgery in prone position. The operation time was about 6 hours. About 30 minutes after transferring to postanesthesia care unit (PACU), patient was awake and complained of losing his eyesight. There was no vision and light perception in his right eye on primary examination. Urgent ophthalmologist consultation was requested. In ophthalmology examinations, the pupil reflex to light was absent in the right eye. After obtaining patients and his family informed consent, four hours after the operation, 40000 I.U. of recombinant human erythropoietin (rhEPO) was administered for patient in PACU (IV infusion, in 30 min). An ophthalmologist visited him every 6 hours after administration of rhEPO. The patient was transferred to intensive care unit (ICU) one hour later with total visual loss in the right eye. Ophthalmologic examination after the second dose of rhEPO, 30 hours after the operation, reported pupil reflex enhancement and light perception in his right eye. Finally the third dose of rhEPO (40000 I.U., IV infusion) was administered on the third day. Ophthalmologic examination after the third dose of rhEPO, 60 hours after the operation, reported normal pupillary light reflex of the right eye and visual acuity improvement to 20/20. The patient was discharged from hospital after six days, with normal visual acuity and without any new complications except surgical site pain. Conclusions: Our case report showed the therapeutic effect of rhEPO in complete curing of POVL. Regarding the side effects of EPO such as thrombogenic effects or mild hemodynamic changes like transient sinus tachycardia during infusion, it seems that beneficial effects of EPO is more than its disadvantages and expenses, for patients with POVL. PMID:24790903

Light, electron microscopic and immunohistochemical study of the effect of low-dose aspirin during the proestrus phase on rat endometrium in the preimplantation period.

PubMed

Ateş, Utku; Baka, Meral; Turgut, Mehmet; Uyanikgil, Yiğit; Ulker, Sibel; Yilmaz, Ozlem; Tavmergen, Erol; Yurtseven, Mine

2007-04-01

To evaluate structural alterations in rat endometrium at preimplantation following treatment with aspirin beginning from proestrus by light microscopy, electron microscopy and immunohistochemical techniques. Twenty rats were divided into control (n = 10) and experimental (n = 10) groups. Experimental rats were treated with low-dose aspirin daily (2 mg/kg/day) during estrus, beginning from the proestrus phase, mated at end of cycle and treated with aspirin. Untreated pregnant rats were the control group. Rats in both groups were sacrificed at the 84th pregnancy hour; the uterus was rapidly removed and dissected free of surrounding adipose tissue. Uteri specimens from nonpregnant rats were transferred into fixative solution and processed for light, electron microscopic and immunohistochemical study. Light and electron microscopy of endometrium from control rats conformed to mid-diestrus phase; endometrial histology of the aspirin-treated group conformed to late diestrus phase. The endometrial layer was significantly thicker in the aspirin-treated group compared to the untreated control group (p <0.001). No significant difference was found in vessel number between groups. Staining with alphaV integrin was more dense in the aspirin-treated group. Based on histologic findings, we suggest low-dose aspirin has positive effects on preparing endometrium before implantation.

Effects of sublethal fenitrothion ingestion on cholinesterase inhibition, standard metabolism, thermal preference, and prey-capture ability in the Australian central bearded dragon (Pogona vitticeps, Agamidae).

PubMed

Bain, David; Buttemer, William A; Astheimer, Lee; Fildes, Karen; Hooper, Michael J

2004-01-01

The central bearded dragon (Pogona vitticeps) is a medium-sized lizard that is common in semiarid habitats in Australia and that potentially is at risk of fenitrothion exposure from use of the chemical in plague locust control. We examined the effects of single sublethal doses of this organophosphate (OP; low dose = 2.0 mg/kg; high dose = 20 mg/kg; control = vehicle alone) on lizard thermal preference, standard metabolic rate, and prey-capture ability. We also measured activities of plasma total cholinesterase (ChE) and acetylcholinesterase before and at 0, 2, 8, 24, 120, and 504 h after OP dosing. Predose plasma total ChE activity differed significantly between sexes and averaged 0.66 +/- 0.06 and 0.45 +/- 0.06 micromol/min/ml for males and females, respectively. Approximately 75% of total ChE activity was attributable to butyrylcholinesterase. Peak ChE inhibition reached 19% 2 h after OP ingestion in the low-dose group, and 68% 8 h after ingestion in high-dose animals. Neither OP doses significantly affected diurnal body temperature, standard metabolic rate, or feeding rate. Plasma total ChE levels remained substantially depressed up to 21 d after dosing in the high-dose group, making this species a useful long-term biomonitor of OP exposure in its habitat.

Monte Carlo calculation of skyshine'' neutron dose from ALS (Advanced Light Source)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moin-Vasiri, M.

1990-06-01

This report discusses the following topics on skyshine'' neutron dose from ALS: Sources of radiation; ALS modeling for skyshine calculations; MORSE Monte-Carlo; Implementation of MORSE; Results of skyshine calculations from storage ring; and Comparison of MORSE shielding calculations.

Low-level light therapy induces mucosal healing in a murine model of dextran-sodium-sulfate induced colitis.

PubMed

Zigmond, Ehud; Varol, Chen; Kaplan, Michail; Shapira, Oz; Melzer, Ehud

2014-08-01

The aim of this study was to demonstrate the effect of low-level light therapy (LLLT) in an acute colitis model in mice. Low-level light therapy (LLLT) has been shown to be an effective treatment for various inflammatory processes such as oral mucositis and diabetic foot ulcers. Colitis was induced by dextran sodium sulfate (DSS) in mice in four blinded controlled studies (validation of model, efficacy study, and two studies for evaluation of optimal dose). LLLT was applied to the colon utilizing a small diameter endoscope with an LED-based light source in several wavelengths (440, 660, and 850 nm at 1 J/cm(2)) and then 850 nm at several doses (1, 0.5, 0.25, and 0.1 J/cm(2)). LLLT was initiated 1 day prior to induction of colitis and went on for the 6 day induction period as well as for the following 3-10 days. Dose was controlled by changing exposure time. Disease activity was scored endoscopically and by histopathological assessment. Statistically significant improvement in disease severity was observed in the treatment groups compared with the control groups. The three wavelengths used demonstrated efficacy, and a clear dose-response curve was observed for one of the wavelengths (850 nm). On day 11, colonoscopic scoring in the sham-treated mice increased from 7.9±1.3 to 12.2±2.2, while activity in all treated groups remained stable. Photobiostimulation with LLLT has a significant positive effect on disease progression in mice with DSS colitis.

Benefits of online in vivo dosimetry for single-fraction total body irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eaton, David J., E-mail: davideaton@nhs.net; Warry, Alison J.; Trimble, Rachel E.

Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013,more » with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources.« less

Fast method for in-flight estimation of total dose from protons and electrons using RADE Minstrument on JUICE

NASA Astrophysics Data System (ADS)

Hajdas, Wojtek; Mrigakshi, Alankrita; Xiao, Hualin

2017-04-01

The primary concern of the ESA JUICE mission to Jupiter is the harsh particle radiation environment. Ionizing particles introduce radiation damage by total dose effects, displacement damages or single events effects. Therefore, both the total ionizing dose and the displacement damage equivalent fluence must be assessed to alert spacecraft and its payload as well as to quantify radiation levels for the entire mission lifetime. We present a concept and implementations steps for simplified method used to compute in flight a dose rate and total dose caused by protons. We also provide refinement of the method previously developed for electrons. The dose rates values are given for predefined active volumes located behind layers of materials with known thickness. Both methods are based on the electron and proton flux measurements provided by the Electron and Proton Detectors inside the Radiation Hard Electron Monitor (RADEM) located on-board of JUICE. The trade-off between method accuracy and programming limitations for in-flight computations are discussed. More comprehensive and precise dose rate computations based on detailed analysis of all stack detectors will be made during off-line data processing. It will utilize full spectral unfolding from all RADEM detector subsystems.

Kontekst stratygraficzny zastosowania różnych odmian metody termoluminescencyjnej w datowaniu lessów z terenu Polski południowo-wschodniej i Ukrainy północno-zachodniej

NASA Astrophysics Data System (ADS)

Kusiak, Jarosław

2008-01-01

Loess profiles contain a complex but usually incomplete sequence of deposits. In order to chronologically organize deposit layers accessible in different exposures it is necessary to use absolute dating methods. The 14C, TL and OSL methods are widely used for dating of the Upper Pleistocene deposits whereas to older Pleistocene deposits only luminescence methods are applied. Some attempts are made to use the OSL method for dating of the deposits older than the Upper Pleistocene. However, the OSL ages seem to be consistently lower than the TL ages, and also considerably underestimated with reference to stratigraphic interpretation. This fact indicates that the TL method should be used above all. The possibility of TL dating of loesses is connected with their aeolian origin. The obtained TL age should correspond to geological time when mineral grains constituting deposit were exposed to sunlight before deposition. Such exactly condition is met in case of loess deposits. There are many variants of thermoluminescence method because different measuring procedures can be used. Depending on the used procedure, the TL ages obtained for the same sample can be considerably different. The manner of equivalent dose determination is decisive for the obtained TL ages. The factors influencing the value of equivalent dose are presented in this paper. The equivalent dose is determined by comparison of thermoluminescence measured for a given sample with thermoluminescence of the same sample after irradiation in laboratory with known doses of ionizing radiation. The following criteria should be taken into account: size of mineral grains, relation between thermoluminescence and heating temperature, way of reduction of unstable thermoluminescence, and the results of plateau test. The variant of thermoluminescence method used in the TL Laboratory of the Department of Physical Geography and Palaeogeography, Maria Curie-Skłodowska University in Lublin is as follows. The dose rate is determined by gamma spectrometry. The equivalent dose is determined by the total-bleach technique for the 45-63 μm fraction. Blue light obtained using the BG-28 filter is applied. Samples are preheated at 160°C for 3 hours before measurement. Light sum is read as the maximum height of glow curve. The application of such measurement procedure allows reliable dating of climatic episodes recorded in loess deposits not only related to the last glacial but also in older ones.

[Action of the radiation from a neon laser and from noncoherent blue light on Escherichia coli bacteria].

PubMed

Tiflova, O A; Karu, T I

1986-01-01

It was shown that under defined conditions blue light can accelerate E. coli WP2 growth. The stimulatory effect is a function of radiation dose, intensity wave length, and postirradiation incubation time.

Image-guided total marrow and total lymphatic irradiation using helical tomotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schultheiss, Timothy E.; Wong, Jeffrey; Liu, An

2007-03-15

Purpose: To develop a treatment technique to spare normal tissue and allow dose escalation in total body irradiation (TBI). We have developed intensity-modulated radiotherapy techniques for the total marrow irradiation (TMI), total lymphatic irradiation, or total bone marrow plus lymphatic irradiation using helical tomotherapy. Methods and Materials: For TBI, we typically use 12 Gy in 10 fractions delivered at an extended source-to-surface distance (SSD). Using helical tomotherapy, it is possible to deliver equally effective doses to the bone marrow and lymphatics while sparing normal organs to a significant degree. In the TMI patients, whole body skeletal bone, including the ribsmore » and sternum, comprise the treatment target. In the total lymphatic irradiation, the target is expanded to include the spleen and major lymph node areas. Sanctuary sites for disease (brain and testes) are included when clinically indicated. Spared organs include the lungs, esophagus, parotid glands, eyes, oral cavity, liver, kidneys, stomach, small and large intestine, bladder, and ovaries. Results: With TBI, all normal organs received the TBI dose; with TMI, total lymphatic irradiation, and total bone marrow plus lymphatic irradiation, the visceral organs are spared. For the first 6 patients treated with TMI, the median dose to organs at risk averaged 51% lower than would be achieved with TBI. By putting greater weight on the avoidance of specific organs, greater sparing was possible. Conclusion: Sparing of normal tissues and dose escalation is possible using helical tomotherapy. Late effects such as radiation pneumonitis, veno-occlusive disease, cataracts, neurocognitive effects, and the development of second tumors should be diminished in severity and frequency according to the dose reduction realized for the organs at risk.« less

The effect of aspirin dosing on platelet function in diabetic and nondiabetic patients: an analysis from the aspirin-induced platelet effect (ASPECT) study.

PubMed

DiChiara, Joseph; Bliden, Kevin P; Tantry, Udaya S; Hamed, Miruais S; Antonino, Mark J; Suarez, Thomas A; Bailon, Oscar; Singla, Anand; Gurbel, Paul A

2007-12-01

Diabetic patients may have a higher prevalence of platelet aspirin resistance than nondiabetic patients. Our goal was to analyze platelet aspirin responsiveness to various aspirin doses in diabetic and nondiabetic patients. We examined the effect of aspirin (81, 162, and 325 mg/day for 4 weeks each) on platelet aspirin responsiveness in 120 stable outpatients (30 diabetic patients and 90 nondiabetic patients) with coronary artery disease (CAD) using light transmittance aggregometry (LTA), VerifyNow, platelet function analyzer (PFA)-100, and levels of urinary 11-dehydro-thromboxane B(2) (11-dh-TxB(2)). In the total group, a low prevalence (0-2%) of aspirin resistance was observed with all aspirin doses as determined by arachidonic acid-induced LTA. Aspirin resistance was higher at the 81-mg dose in diabetic versus nondiabetic patients using collagen-induced LTA (27 vs. 4%, P = 0.001), VerifyNow (13 vs. 3%, P = 0.05), and urinary 11-dh-TxB(2) (37 vs. 17%, P = 0.03). Diabetic patients treated with 81 mg exhibited higher platelet function measured by VerifyNow, collagen- and ADP-induced LTA, and 11-dh-TxB(2) levels (P

RADIOACTIVITY DOSAGE OF ORNAMENTAL GRANITIC ROCKS BASED ON CHEMICAL, MINERALOGICAL AND LITHOLOGICAL DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salas, H.T.; Nalini, H.A. Jr.; Mendes, J.C.

2004-10-03

One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite and zircon. Chemical analysis revealed concentrations of uranium of {le} 30ppm, and thorium {le} 130ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for floor tiles in a standard room for samples withmore » total concentration of uranium and thorium greater than 60ppm. On the basis of calculations of {sup 232}Th, {sup 40}K and {sup 226}Ra from Th, K and U analysis, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.« less

Comparison of Transport Codes, HZETRN, HETC and FLUKA, Using 1977 GCR Solar Minimum Spectra

NASA Technical Reports Server (NTRS)

Heinbockel, John H.; Slaba, Tony C.; Tripathi, Ram K.; Blattnig, Steve R.; Norbury, John W.; Badavi, Francis F.; Townsend, Lawrence W.; Handler, Thomas; Gabriel, Tony A.; Pinsky, Lawrence S.;

Influence of dimethyl dicarbonate on the resistance of Escherichia coli to a combined UV-Heat treatment in apple juice

PubMed Central

Gouma, Maria; Gayán, Elisa; Raso, Javier; Condón, Santiago; Álvarez, Ignacio

2015-01-01

Commercial apple juice inoculated with Escherichia coli was treated with UV-C, heat (55°C) and dimethyl dicarbonate – DMDC (25, 50, and 75 mg/L)-, applied separately and in combination, in order to investigate the possibility of synergistic lethal effects. The inactivation levels resulting from each treatment applied individually for a maximum treatment time of 3.58 min were limited, reaching 1.2, 2.9, and 0.06 log10 reductions for UV, heat, and DMDC (75 mg/L), respectively. However, all the investigated combinations resulted in a synergistic lethal effect, reducing the total treatment time and UV dose, with the synergistic lethal effect being higher when larger concentrations of DMDC were added to the apple juice. The addition of 75 mg/L of DMDC prior to the combined UV-C light treatment at 55°C resulted in 5 log10 reductions after only 1.8 min, reducing the treatment time and UV dose of the combined UV-Heat treatment by 44%. PMID:26042117

Single-dose radiation therapy for prevention of heterotopic ossification after total hip arthroplasty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Healy, W.L.; Lo, T.C.; Covall, D.J.

1990-12-01

Single-dose radiation therapy was prospectively evaluated for its efficacy in prevention of heterotopic ossification in patients at high risk after total hip arthroplasty. Thirty-one patients (34 hips) were treated between 1981 and 1988. Risk factors for inclusion in the protocol included prior evidence of heterotopic ossification, ankylosing spondylitis, and diffuse idiopathic skeletal hyperostosis. Patients with hypertrophic osteoarthritis or traumatic arthritis with osteophytes were not included. Operations on 34 hips included 19 primary total and 11 revision total hip arthroplasties and 4 excisions of heterotopic ossification. All patients received radiotherapy to the hip after operation with a single dose of 700more » centigray. Radiotherapy is recommended on the first postoperative day. After this single-dose radiation treatment, no patient had clinically significant heterotopic ossification. Recurrent disease developed in two hips (6%), as seen on radiography (grades 2 and 3). This series documents a 100% clinical success rate and a 94% radiographic success rate in preventing heterotopic ossification in patients at high risk after total hip arthroplasty. Single-dose radiotherapy is as effective as other radiation protocols in preventing heterotopic ossification after total hip arthroplasty. It is less expensive and easier to administer than multidose radiotherapy.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Battum, LJ van; Heukelom, S

Purpose This study investigates the origin of lateral optical density (OD) variation for Gafchromic film (EBT and EBT2) scanned in transmission mode with Epson flatbed scanners (1680 Expression Pro and 10000XL). Effects investigated are: cross talk, optical path length and polarization. Methods Cross talk has been examined with triangular shaped light-transmission sheets with OD ranging from 0 to opaque. Optical path length has been studied with absorptive and reflective OD-filters (OD range 0.2 to 2.0). Dependency on light-polarization on the scanner read out has been investigated using linear polarizer sheets. All experiments have been performed at centre scanner position (normmore » point) and at several lateral scan positions, without and with (un)irradiated EBT-film. Dose values used ranged between 0.2 to 9 Gy, yielding an OD-range between 0.25 to 1.1. Results The lateral OD variation is dose dependent and increases up to 14% at most lateral position for dose up to 9 Gy. Cross talk effect contributes to 0.5% in clinical used OD ranges but equals 2% for extreme high dose gradients. Film induced optical path length will effect the lateral OD variation up to 3% at most lateral points. Light polarization is inherent present in these scanners due to multiple reflection on mirrors. In addition film induced polarization is the most important effect generating the observed lateral OD variation. Both Gafchromic film base and sensitive layer have polarizing capabilities; for the sensitive layer its influence is dose dependent. Conclusions Lateral OD variation origins from optical physics (i.e. polarization and reflection) related to scanner and film construction. Cross talk can be ignored in film dosimetry for clinical used dose values and gradients. Therefore it is recommended to determine the lateral OD variation per film type and scanner.« less

A Mathematical Model of the Circadian Phase-Shifting Effects of Exogenous Melatonin

PubMed Central

Breslow, Emily R.; Phillips, Andrew J.K.; Huang, Jean M.; St. Hilaire, Melissa A.; Klerman, Elizabeth B.

2013-01-01

Melatonin is endogenously produced and released in humans during nighttime darkness and is suppressed by ocular light exposure. Exogenous melatonin is used to induce circadian phase shifts and sleep. The circadian phase-shifting ability of a stimulus (e.g., melatonin or light) relative to its timing may be displayed as a phase response curve (PRC). Published PRCs to exogenous melatonin show a transition from phase advances to delays approximately 1 h after dim light melatonin onset. A previously developed mathematical model simulates endogenous production and clearance of melatonin as a function of circadian phase, light-induced suppression, and resetting of circadian phase by light. We extend this model to include the pharmacokinetics of oral exogenous melatonin and phase-shifting effects via melatonin receptors in the suprachiasmatic nucleus of the mammalian hypothalamus. Model parameters are fit using 2 data sets: (1) blood melatonin concentration following a 0.3- or 5.0-mg dose, and (2) a PRC to a 3.0-mg dose of melatonin. After fitting to the 3.0-mg PRC, the model correctly predicts that, by comparison, the 0.5-mg PRC is slightly decreased in amplitude and shifted to a later circadian phase. This model also reproduces blood concentration profiles of various melatonin preparations that differ only in absorption rate and percentage degradation by first-pass hepatic metabolism. This model can simulate experimental protocols using oral melatonin, with potential application to guide dose size and timing to optimally shift and entrain circadian rhythms. PMID:23382594

Evaluation of total-dose iron sucrose infusions in patients with iron deficiency anemia.

PubMed

Wall, Geoffrey C; Pauly, Rebecca A

2008-01-15

The safety and efficacy of a total-dose iron sucrose infusion protocol used in a large, tertiary care teaching hospital were studied. Nondialysis-dependent patients ages 18 years or older who received > or =250 mg of iron sucrose as a single i.v. infusion between January 2005 and January 2007 were eligible for study inclusion. The protocol for total-dose iron sucrose infusion was the same for all patients. The total dose of iron sucrose for each patient was calculated using an equation that included the desired hemoglobin (Hb) value, observed Hb level, ideal body weight, and sex. The calculated dose was divided into portions, rounded to the nearest 250 mg, and administered over four hours every other day. Outcomes measured included Hb, transferrin saturation, and serum ferritin values. A total of 26 patients met the inclusion criteria. The mean +/- S.D. Hb concentration before total-dose iron sucrose infusion was 9.37 +/- 0.9 g/dL, and the mean +/- S.D. corpuscular volume was 75 +/- 7.1 mum(3). The mean +/- S.D. postinfusion Hb concentration for 19 patients for whom follow-up Hb levels were available was 11.4 +/- 1.2 g/dL, significantly higher than the 9.45 +/- 0.8 g/dL measured before the first infusion (p = 0.03). No significant adverse effects were reported in 47 of 49 infusions, with 2 patients experiencing mild nausea. A treatment protocol consisting of alternate-day total-dose iron sucrose infusions was well tolerated and appeared to be effective in improving Hb concentrations in patients with iron deficiency anemia and without chronic kidney disease.

Phototherapy in skeletal muscle performance and recovery after exercise: effect of combination of super-pulsed laser and light-emitting diodes.

PubMed

Antonialli, Fernanda Colella; De Marchi, Thiago; Tomazoni, Shaiane Silva; Vanin, Adriane Aver; dos Santos Grandinetti, Vanessa; de Paiva, Paulo Roberto Vicente; Pinto, Henrique Dantas; Miranda, Eduardo Foschini; de Tarso Camillo de Carvalho, Paulo; Leal-Junior, Ernesto Cesar Pinto

2014-11-01

Recent studies with phototherapy have shown positive results in enhancement of performance and improvement of recovery when applied before exercise. However, several factors still remain unknown such as therapeutic windows, optimal treatment parameters, and effects of combination of different light sources (laser and LEDs). The aim of this study was to evaluate the effects of phototherapy with the combination of different light sources on skeletal muscle performance and post-exercise recovery, and to establish the optimal energy dose. A randomized, double-blinded, placebo-controlled trial with participation of 40 male healthy untrained volunteers was performed. A single phototherapy intervention was performed immediately after pre-exercise (baseline) maximum voluntary contraction (MVC) with a cluster of 12 diodes (4 of 905 nm lasers-0.3125 mW each, 4 of 875 nm LEDs-17.5 mW each, and 4 of 670 nm LEDs-15 mW each- manufactured by Multi Radiance Medical™) and dose of 10, 30, and 50 J or placebo in six sites of quadriceps. MVC, delayed onset muscle soreness (DOMS), and creatine kinase (CK) activity were analyzed. Assessments were performed before, 1 min, 1, 24, 48, 72, and 96 h after eccentric exercise protocol employed to induce fatigue. Phototherapy increased (p < 0.05) MVC was compared to placebo from immediately after to 96 h after exercise with 10 or 30 J doses (better results with 30 J dose). DOMS was significantly decreased compared to placebo (p < 0.05) with 30 J dose from 24 to 96 h after exercise, and with 50 J dose from immediately after to 96 h after exercise. CK activity was significantly decreased (p < 0.05) compared to placebo with all phototherapy doses from 1 to 96 h after exercise (except for 50 J dose at 96 h). Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30 J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage.

Evaluation of dose variation during total skin electron irradiation using thermoluminescent dosimeters.

PubMed

Weaver, R D; Gerbi, B J; Dusenbery, K E

1995-09-30

To determine acceptable dose variation using thermoluminescent dosimeters (TLD) in the treatment of Mycosis Fungoides with total skin electron beam (TSEB) irradiation. From 1983 to 1993, 22 patients were treated with total skin electron beam therapy in the standing position. A six-field technique was used to deliver 2 Gy in two days, treating 4 days per week, to a total dose of 35 to 40 Gy using a degraded 9 MeV electron beam. Thermoluminescent dosimeters were placed on several locations of the body and the results recorded. The variations in these readings were analyzed to determine normal dose variation for various body locations during TSEB. The dose to flat surfaces of the body was essentially the same as the dose to the prescription point. The dose to tangential surfaces was within +/- 10% of the prescription dose, but the readings showed much more variation (up to 24%). Thin areas of the body showed large deviations from the prescription dose along with a large amount of variation in the readings (up to 22%). Special areas of the body, such as the perineum and eyelid, showed large deviations from the prescription dose with very large (up to 40%) variations in the readings. The TLD results of this study will be used as a quality assurance check for all new patients treated with TSEB. The results of the TLDs will be compared with this baseline study to determine if the delivered dose is within acceptable ranges. If the TLD results fall outside the acceptable limits established above, then the patient position can be modified or the technique itself evaluated.

Comparsion of light dose on topical ALA-mediated photodynamic therapy for DMBA-induced hamster buccal pouch premalignant lesions

NASA Astrophysics Data System (ADS)

Yang, Deng-Fu; Tseng, Meng-Ke; Liu, Chung-Ji; Hsu, Yih-Chih

2012-03-01

Oral cancer has becomes the most prominent male cancer disease due to the local betel nut chewing habit combing with smoking and alcohol-drinking lifestyle. In order to minimize the systemic phototoxic effect of 5-aminolevulinic acid (ALA), this study was designed to use a topical ALA-mediated PDT for treatment of DMBA-induced hamster buccal pouch cancerous lesions. DMBA was applied to one of the buccal pouches of hamsters thrice a week for 8 to 10 weeks. Precancerous lesions were induced and proven by histological examination. These DMBA-induced cancerous lesions were used for testing the efficacy of topical ALA -mediated PDT. We found that ALA reached its peak level in cancerous lesions about 2.5 hrs after topical application of ALA gel. The precancerous lesions in hamsters were then treated with topical ALA -mediated PDT with light exposure dose of 75 and 100 J/cm2 using LED 635 nm Wonderlight device. It is suggesting that optimization of the given light dose is critical to the success of PDT results.

The impact of emollients on phototherapy: a review.

PubMed

Asztalos, Manuela L; Heller, Misha M; Lee, Eric S; Koo, John

2013-05-01

When treating psoriasis, various topical emollients exist that can affect the penetration of ultraviolet radiation in phototherapy. Compared with normal-appearing skin with a reflectance of 4% to 5%, psoriatic skin has higher reflectance as a result of its increased air-to-corneocyte interfaces. Studies have tested the effect of emollients on light penetration by assessing psoriatic plaque clearance, differences in minimal erythema dose, and physical properties of the emollient (eg, monochromatic protection factor and absorbance). Psoriatic plaque clearance was found to improve with serous (thin liquid)-based emollients (eg, Vaseline oil [Unilever, Blackfriars, London, UK], mineral oil, and glycerol), whereas clearance decreased with salicylic acid and viscous-based emollients (eg, petrolatum). Emollients with high ultraviolet absorbance properties increased minimal erythema dose, and those with low absorbance properties decreased minimal erythema dose. Interestingly, when a liquid emollient with a refractive index close to that of normal-appearing skin was applied, there was a net increase in light absorption, or a reduction in reflection that exceeded the emollient's innate ability to absorb light. Copyright © 2012 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

A quality assurance program for clinical PDT

NASA Astrophysics Data System (ADS)

Dimofte, Andreea; Finlay, Jarod; Ong, Yi Hong; Zhu, Timothy C.

2018-02-01

Successful outcome of Photodynamic therapy (PDT) depends on accurate delivery of prescribed light dose. A quality assurance program is necessary to ensure that light dosimetry is correctly measured. We have instituted a QA program that include examination of long term calibration uncertainty of isotropic detectors for light fluence rate, power meter head intercomparison for laser power, stability of the light-emitting diode (LED) light source integrating sphere as a light fluence standard, laser output and calibration of in-vivo reflective fluorescence and absorption spectrometers. We examined the long term calibration uncertainty of isotropic detector sensitivity, defined as fluence rate per voltage. We calibrate the detector using the known calibrated light fluence rate of the LED light source built into an internally baffled 4" integrating sphere. LED light sources were examined using a 1mm diameter isotropic detector calibrated in a collimated beam. Wavelengths varying from 632nm to 690nm were used. The internal LED method gives an overall calibration accuracy of +/- 4%. Intercomparison among power meters was performed to determine the consistency of laser power and light fluence rate measured among different power meters. Power and fluence readings were measured and compared among detectors. A comparison of power and fluence reading among several power heads shows long term consistency for power and light fluence rate calibration to within 3% regardless of wavelength. The standard LED light source is used to calibrate the transmission difference between different channels for the diffuse reflective absorption and fluorescence contact probe as well as isotropic detectors used in PDT dose dosimeter.

Characterization of Radiation Hardened Bipolar Linear Devices for High Total Dose Missions

NASA Technical Reports Server (NTRS)

McClure, Steven S.; Harris, Richard D.; Rax, Bernard G.; Thorbourn, Dennis O.

2012-01-01

Radiation hardened linear devices are characterized for performance in combined total dose and displacement damage environments for a mission scenario with a high radiation level. Performance at low and high dose rate for both biased and unbiased conditions is compared and the impact to hardness assurance methodology is discussed.

Alcohol and bone: review of dose effects and mechanisms.

PubMed

Maurel, D B; Boisseau, N; Benhamou, C L; Jaffre, C

2012-01-01

Alcohol is widely consumed across the world. It is consumed in both social and cultural settings. Until recently, two types of alcohol consumption were recognized: heavy chronic alcohol consumption or light consumption. Today, there is a new pattern of consumption among teenagers and young adults namely: binge drinking. Heavy alcohol consumption is detrimental to many organs and tissues, including bones, and is known to induce secondary osteoporosis. Some studies, however, have reported benefits from light alcohol consumption on bone parameters. To date, little is known regarding the effects of binge drinking on bone health. Here, we review the effects of three different means of alcohol consumption: light, heavy, and binge drinking. We also review the detailed literature on the different mechanisms by which alcohol intake may decrease bone mass and strength. The effects of alcohol on bone are thought to be both direct and indirect. The decrease in bone mass and strength following alcohol consumption is mainly due to a bone remodeling imbalance, with a predominant decrease in bone formation. Recent studies, however, have reported new mechanisms by which alcohol may act on bone remodeling, including osteocyte apoptosis, oxidative stress, and Wnt signalling pathway modulation. The roles of reduced total fat mass, increased lipid content in bone marrow, and a hypoleptinemia are also discussed.

Tumor Induction in Mice After Localized Single- or Fractionated-Dose Irradiation: Differences in Tumor Histotype and Genetic Susceptibility Based on Dose Scheduling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edmondson, Elijah F., E-mail: elijah.edmondson@colostate.edu; Hunter, Nancy R.; Weil, Michael M.

2015-07-15

Purpose: To investigate differences in tumor histotype, incidence, latency, and strain susceptibility in mice exposed to single-dose or clinically relevant, fractioned-dose γ-ray radiation. Methods and Materials: C3Hf/Kam and C57BL/6J mice were locally irradiated to the right hindlimb with either single large doses between 10 and 70 Gy or fractionated doses totaling 40 to 80 Gy delivered at 2-Gy/d fractions, 5 d/wk, for 4 to 8 weeks. The mice were closely evaluated for tumor development in the irradiated field for 800 days after irradiation, and all tumors were characterized histologically. Results: A total of 210 tumors were induced within the radiation field in 788 mice. Anmore » overall decrease in tumor incidence was observed after fractionated irradiation (16.4%) in comparison with single-dose irradiation (36.1%). Sarcomas were the predominant postirradiation tumor observed (n=201), with carcinomas occurring less frequently (n=9). The proportion of mice developing tumors increased significantly with total dose for both single-dose and fractionated schedules, and latencies were significantly decreased in mice exposed to larger total doses. C3Hf/Kam mice were more susceptible to tumor induction than C57BL/6J mice after single-dose irradiation; however, significant differences in tumor susceptibilities after fractionated radiation were not observed. For both strains of mice, osteosarcomas and hemangiosarcomas were significantly more common after fractionated irradiation, whereas fibrosarcomas and malignant fibrous histiocytomas were significantly more common after single-dose irradiation. Conclusions: This study investigated the tumorigenic effect of acute large doses in comparison with fractionated radiation in which both the dose and delivery schedule were similar to those used in clinical radiation therapy. Differences in tumor histotype after single-dose or fractionated radiation exposures provide novel in vivo evidence for differences in tumor susceptibility among stromal cell populations.« less

SU-E-T-540: Volumetric Modulated Total Body Irradiation Using a Rotational Lazy Susan-Like Immobilization System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, X; Hrycushko, B; Lee, H

2014-06-01

Purpose: Traditional extended SSD total body irradiation (TBI) techniques can be problematic in terms of patient comfort and/or dose uniformity. This work aims to develop a comfortable TBI technique that achieves a uniform dose distribution to the total body while reducing the dose to organs at risk for complications. Methods: To maximize patient comfort, a lazy Susan-like couch top immobilization system which rotates about a pivot point was developed. During CT simulation, a patient is immobilized by a Vac-Lok bag within the body frame. The patient is scanned head-first and then feet-first following 180° rotation of the frame. The twomore » scans are imported into the Pinnacle treatment planning system and concatenated to give a full-body CT dataset. Treatment planning matches multiple isocenter volumetric modulated arc (VMAT) fields of the upper body and multiple isocenter parallel-opposed fields of the lower body. VMAT fields of the torso are optimized to satisfy lung dose constraints while achieving a therapeutic dose to the torso. The multiple isocenter VMAT fields are delivered with an indexed couch, followed by body frame rotation about the pivot point to treat the lower body isocenters. The treatment workflow was simulated with a Rando phantom, and the plan was mapped to a solid water slab phantom for point- and film-dose measurements at multiple locations. Results: The treatment plan of 12Gy over 8 fractions achieved 80.2% coverage of the total body volume within ±10% of the prescription dose. The mean lung dose was 8.1 Gy. All ion chamber measurements were within ±1.7% compared to the calculated point doses. All relative film dosimetry showed at least a 98.0% gamma passing rate using a 3mm/3% passing criteria. Conclusion: The proposed patient comfort-oriented TBI technique provides for a uniform dose distribution within the total body while reducing the dose to the lungs.« less

Low-dose CT for quantitative analysis in acute respiratory distress syndrome

DTIC Science & Technology

2013-08-31

noise of scans performed at 140, 60, 15 and 7.5 mAs corresponded to 10, 16, 38 and 74 Hounsfield Units , respectively. Conclusions: A reduction of...slice of a series, total lung volume, total lung tissue mass and frequency distribution of lung CT numbers expressed in Hounsfield Units (HU) were...tomography; HU: Hounsfield units ; CTDIvol: volumetric computed tomography dose index; DLP: dose length product; E: effective dose; SD: standard deviation

LM193 Dual Differential Comparator Total Ionizing Dose Test Report

NASA Technical Reports Server (NTRS)

Topper, Alyson; Forney, James; Campola, Michael

2017-01-01

The purpose of this test was to characterize the flight lot of Texas Instruments' LM193 (flight part number is 5962-9452601Q2A) for total dose response. This test served as the radiation lot acceptance test (RLAT) for the lot date code (LDC) tested. Low dose rate (LDR) irradiations were performed in this test so that the device susceptibility to enhanced low dose rate sensitivity (ELDRS) was determined.

Dose-Dependent Model of Caffeine Effects on Human Vigilance during Total Sleep Deprivation

DTIC Science & Technology

2014-05-20

does not consider the absorption of caffeine . This is a reasonable approximation for caffeine when ingested via coffee , tea, energy drinks, and most...Dose-dependent model of caffeine effects on human vigilance during total sleep deprivation Sridhar Ramakrishnan a, Srinivas Laxminarayan a, Nancy J...We modeled the dose-dependent effects of caffeine on human vigilance. The model predicted the effects of both single and repeated caffeine doses

Meeting The Joint Commission's Dose Incident Identification and External Benchmarking Requirements Using the ACR's Dose Index Registry.

PubMed

Bohl, Michael A; Goswami, Roopa; Strassner, Brett; Stanger, Paula

2016-08-01

The purpose of this investigation was to evaluate the potential of using the ACR's Dose Index Registry(®) to meet The Joint Commission's requirements to identify incidents in which the radiation dose index from diagnostic CT examinations exceeded the protocol's expected dose index range. In total, 10,970 records in the Dose Index Registry were statistically analyzed to establish both an upper and lower expected dose index for each protocol. All 2015 studies to date were then retrospectively reviewed to identify examinations whose total examination dose index exceeded the protocol's defined upper threshold. Each dose incident was then logged and reviewed per the new Joint Commission requirements. Facilities may leverage their participation in the ACR's Dose Index Registry to fully meet The Joint Commission's dose incident identification review and external benchmarking requirements. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Low-Dose, Long-Wave UV Light Does Not Affect Gene Expression of Human Mesenchymal Stem Cells

PubMed Central

Wong, Darice Y.; Ranganath, Thanmayi; Kasko, Andrea M.

2015-01-01

Light is a non-invasive tool that is widely used in a range of biomedical applications. Techniques such as photopolymerization, photodegradation, and photouncaging can be used to alter the chemical and physical properties of biomaterials in the presence of live cells. Long-wave UV light (315 nm–400 nm) is an easily accessible and commonly used energy source for triggering biomaterial changes. Although exposure to low doses of long-wave UV light is generally accepted as biocompatible, most studies employing this wavelength only establish cell viability, ignoring other possible (non-toxic) effects. Since light exposure of wavelengths longer than 315 nm may potentially induce changes in cell behavior, we examined changes in gene expression of human mesenchymal stem cells exposed to light under both 2D and 3D culture conditions, including two different hydrogel fabrication techniques, decoupling UV exposure and radical generation. While exposure to long-wave UV light did not induce significant changes in gene expression regardless of culture conditions, significant changes were observed due to scaffold fabrication chemistry and between cells plated in 2D versus encapsulated in 3D scaffolds. In order to facilitate others in searching for more specific changes between the many conditions, the full data set is available on Gene Expression Omnibus for querying. PMID:26418040

The effects of hot carrier and swift heavy ion irradiation on electrical characteristics of advanced 200 GHz SiGe HBTs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vinayakprasanna, N. H.; Praveen, K. C.; Prakash, A. P. Gnana, E-mail: gnanaprakash@physics.uni-mysore.ac.in

The 200 GHz SiGe HBTs were irradiated with 80 MeV Carbon ions up to a total dose of 100 Mrad to understand the degradation in electrical characteristics. The degradation in the electrical characteristics of SiGe HBTs was also studied by mixed mode electrical stress up to 10,000 s. The electrical characteristics were measured before and after every total dose and after fixed stress time. The normalized peak h{sub FE} of the stressed and irradiated SiGe HBTs are compared to estimate the equivalent stress time for a particular total dose. These correlations are drawn for the first time and the resultsmore » will establish a systematic relation between stress time and total dose.« less

Early changes in staurosporine-induced differentiated RGC-5 cells indicate cellular injury response to nonlethal blue light exposure.

PubMed

Zhang, Pei; Huang, Chen; Wang, Wei; Wang, Minshu

2015-06-01

Blue light has been previously demonstrated to induce injury of retinal cells. The cellular responses to nonlethal blue light exposure for each type of retinal cell are of particular interest but remain undetermined. Based on the doses of blue light reported in previous research to be nonlethal to retinal pigment epithelial cells, here we investigated whether and to what extent such doses of blue light are cytotoxic to staurosporine-differentiated RGC-5 cells. RGC-5 cells were differentiated for 24 hours using 200 nM staurosporine. The resulting cells were cultured and exposed to blue light at three different energy levels (1, 10, and 50 J cm(-2)). Cellular morphologies were investigated with an inverted microscope and cell viability was assessed with a Cell Counting Kit-8 (CCK-8) assay. The generation of intracellular reactive oxygen species (ROS) was evaluated by H2DCFDA. After loading of MitoTracker Green FM dye, the mitochondrial contents were analyzed using flow cytometry. The lactate dehydrogenase (LDH) activities in the media were also measured. The level of lipid peroxidation was determined by measuring the amount of malondialdehyde (MDA). Treatment of the cells for 24 hours with 200 nM staurosporine successfully induced the differentiation of RGC-5 cells. No morphological changes were observed in the ssdRGC-5 cells exposed to blue light at 50 J cm(-2), which was the highest energy level tested. Exposure of the ssdRGC-5 cells to this energy level of blue light did, however, decrease their numbers by approximately 72.1% compared to the numbers of such cells found after being left in the dark. Remarkably, the levels of ROS generation and mitochondrial contents were, respectively, increased to 142% and 118% of those of the control by a 10 J cm(-2) exposure of blue light. The LDH activities and MDA levels exhibited no obvious changes in the blue light-exposed ssdRGC-5 cells compared to the control cells. In vitro nonlethal blue light exposure led to cellular damage of staurosporine-differentiated RGC-5 cells. These increases in oxidative stress and mitochondrial content were the early steps of the cellular response to the exposure of relatively low doses (10 J cm(-2)) of blue light.

Dosimetric Evaluation Between Megavoltage Cone-Beam Computed Tomography and Body Mass Index for Intracranial, Thoracic, and Pelvic Localization

DOE Office of Scientific and Technical Information (OSTI.GOV)

VanAntwerp, April E.; Raymond, Sarah M., E-mail: raymons9@ccf.org; Addington, Mark C.

2011-10-01

The aim of this study was to evaluate radiation dose for organs at risk (OAR) within the cranium, thorax, and pelvis from megavoltage cone-beam computed tomography (MV-CBCT). Using a clinical treatment planning system, CBCT doses were calculated from 60 patient datasets using 27.4 x 27.4 cm{sup 2} field size and 200{sup o} arc length. The body mass indices (BMIs) for these patients range from 17.2-48.4 kg/m{sup 2}. A total of 60 CBCT plans were created and calculated with heterogeneity corrections, with monitor units (MU) that varied from 8, 4, and 2 MU per plan. The isocenters of these plans weremore » placed at defined anatomical structures. The maximum dose, dose to the isocenter, and mean dose to the selected critical organs were analyzed. The study found that maximum and isocenter doses were weakly associated with BMI, but linearly associated with the total MU. Average maximum/isocenter doses in the cranium were 10.0 ({+-} 0.18)/7.0 ({+-} 0.08) cGy, 5.0 ({+-} 0.09)/3.5 ({+-} 0.05) cGy, and 2.5 ({+-} .04)/1.8 ({+-} 0.05) cGy for 8, 4, and 2 MU, respectively. Similar trends but slightly larger maximum/isocenter doses were found in the thoracic and pelvic regions. For the cranial region, the average mean doses with a total of 8 MU to the eye, lens, and brain were 9.7 ({+-} 0.12) cGy, 9.1 ({+-} 0.16) cGy, and 7.2 ({+-} 0.10) cGy, respectively. For the thoracic region, the average mean doses to the lung, heart, and spinal cord were 6.6 ({+-} 0.05) cGy, 6.9 ({+-} 1.2) cGy, and 4.7 ({+-} 0.8) cGy, respectively. For the pelvic region, the average mean dose to the femoral heads was 6.4 ({+-} 1.1) cGy. The MV-CBCT doses were linearly associated with the total MU but weakly dependent on patients' BMIs. Daily MV-CBCT has a cumulative effect on the total body dose and critical organs, which should be carefully considered for clinical impacts.« less

Effect of γ-dose rate and total dose interrelation on the polymeric hydrogel: A novel injectable male contraceptive

NASA Astrophysics Data System (ADS)

Jha, Pradeep K.; Jha, Rakhi; Gupta, B. L.; Guha, Sujoy K.

2010-05-01

Functional necessity to use a particular range of dose rate and total dose of γ-initiated polymerization to manufacture a novel polymeric hydrogel RISUG ® (reversible inhibition of sperm under guidance) made of styrene maleic anhydride (SMA) dissolved in dimethyl sulphoxide (DMSO), for its broad biomedical application explores new dimension of research. The present work involves 16 irradiated samples. They were tested by fourier transform infrared spectroscopy, matrix assisted laser desorption/ionization-TOF, field emission scanning electron microscopy, high resolution transmission electron microscopy, etc. to see the interrelation effect of gamma dose rates (8.25, 17.29, 20.01 and 25.00 Gy/min) and four sets of doses (1.8, 2.0, 2.2 and 2.4 kGy) on the molecular weight, molecular weight distribution and porosity analysis of the biopolymeric drug RISUG ®. The results of randomized experiment indicated that a range of 18-24 Gy/min γ-dose rate and 2.0-2.4 kGy γ-total doses is suitable for the desirable in vivo performance of the contraceptive copolymer.

Flavonoids and Tannins from Smilax china L. Rhizome Induce Apoptosis Via Mitochondrial Pathway and MDM2-p53 Signaling in Human Lung Adenocarcinoma Cells.

PubMed

Fu, San; Yang, Yanfang; Liu, Dan; Luo, Yan; Ye, Xiaochuan; Liu, Yanwen; Chen, Xin; Wang, Song; Wu, Hezhen; Wang, Yuhang; Hu, Qiwei; You, Pengtao

2017-01-01

In vitro evidence indicates that Smilax china L. rhizome (SCR) can inhibit cell proliferation. Therefore, in the present study, we analyzed the effects in vitro of SCR extracts on human lung adenocarcinoma A549 cells. Our results showed that A549 cell growth was inhibited in a dose- and time-dependent manner after treatment with SCR extracts. Total flavonoids and total tannins from SCR induced A549 apoptosis in a dose-dependent manner, as shown by our flow cytometry analysis, which was consistent with the alterations in nuclear morphology we observed. In addition, the total apoptotic rate induced by total tannins was higher than the rate induced by total flavonoids at the same dose. Cleaved-caspase-3 protein levels in A549 cells after treatment with total flavonoids or total tannins were increased in a dose-dependent manner, followed by the activation of caspase-8 and caspase-9, finally triggering to PARP cleavage. Furthermore, total flavonoids and total tannins increased the expression of Bax, decreased the expression of Bcl-2, and promoted cytochrome [Formula: see text] release. Moreover, MDM2 and p-MDM2 proteins were decreased, while p53 and p-p53 proteins were increased, both in a dose-dependent manner, after A549 treatment with total flavonoids and total tannins. Finally, cleaved-caspase-3 protein levels in the total flavonoids or total tannins-treated H1299 (p53 null) and p53-knockdown A549 cells were increased. Our results indicated that total flavonoids and total tannins from SCR exerted a remarkable effect in reducing A549 growth through their action on mitochondrial pathway and disruption of MDM2-p53 balance. Hence, our findings demonstrated a potential application of total flavonoids and total tannins from SCR in the treatment of human lung adenocarcinoma.

TH-CD-201-05: Characterization of a Novel Light-Collimating Tank Optical-CT System for 3D Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miles, D; Yoon, S; Adamovics, J

Purpose: Comprehensive 3D dosimetry is highly desirable for advanced clinical QA, but costly optical readout techniques have hindered widespread implementation. Here, we present the first results from a cost-effective Integrated-lens Dry-tank Optical Scanner (IDOS), designed for convenient 3D dosimetry readout of radiochromic plastic dosimeters (e.g. PRESAGE). Methods: The scanner incorporates a novel transparent light-collimating tank, which collimates a point light source into parallel-ray CT geometry. The tank was designed using an in-house Monte-Carlo optical ray-tracing simulation, and was cast in polyurethane using a 3D printed mould. IDOS spatial accuracy was evaluated by imaging a set of custom optical phantoms, withmore » comparison to x-ray CT images. IDOS dose measurement performance was assessed by imaging PRESAGE dosimeters irradiated with simple known dose distributions (e.g., 4 field box 6MV treatment with Varian Linac). Direct comparisons were made to images from our gold standard DLOS scanner and calculated dose distributions from a commissioned Eclipse planning system. Results: All optical CT images were reconstructed at 1mm isotropic resolution. Comparison of IDOS and x-ray CT images of the geometric phantom demonstrated excellent IDOS geometric accuracy (sub-mm) throughout the dosimeter. IDOS measured 3D dose distribution agreed well with prediction from Eclipse, with 95% gamma pass rate at 3%/3mm. Cross-scanner dose measurement gamma analysis shows >90% of pixels passing at 3%/3mm. Conclusion: The first prototype of the IDOS system has demonstrated promising performance, with accurate dosimeter readout and negligible spatial distortion. The use of optical simulations and 3D printing to create a light collimating-tank has dramatically increased convenience and reduced costs by removing the need for expensive lenses and large volumes of refractive matching fluids.« less

The effect of flurbiprofen on the development of anencephaly in early stage chicken embryos.

PubMed

Özeren, Ersin; Er, Uygur; Güvenç, Yahya; Demirci, Adnan; Arıkök, Ata Türker; Şenveli, Engin; Ergün, Rüçhan Behzat

2015-04-01

The study investigated the effect of flurbiprofen on the development of anencephaly in early stage chicken embryos. We looked at four groups with a total of 36 embryos. There was a control group, a normal saline group, a normal-dose group and a high-dose group with ten, ten, eight and eight eggs with embryo respectively. Two embryos in the control group, studied with light microscopy at 48 h, were consistent with 28-29 hours' incubation in the Hamburger-Hamilton System. They had open neural tubes. The other embryos in this group were considered normal. One embryo in the normal saline group was on the occlusion stage at 48 h. One embryo showed an open neural tube. They were compatible with 28-29 hours' incubation in the Hamburger-Hamilton system. The remaining eight embryos showed normal development. In the normal dose group, one embryo showed underdevelopment of the embryonic disc and the embryo was dead. In four embryos, the neural tubes were open. One cranial malformation was found that was complicated with anencephaly in one embryo. In two embryos the neural tubes were closed, as they showed normal development, and they reached their expected stages according to the Hamburger-Hamilton classification. There was no malformation or growth retardation. Four experimental embryos were anencephalic in the high dose group, and three embryos had open neural tubes. One embryo exhibited both anencephaly and a neural tube closure defect. None of the embryos in this group showed normal development. Even the usual therapeutic doses of flurbiprofen increased the risk of neural tube defect. Flurbiprofen was found to significantly increase the risk of anencephaly. The provision of improved technical materials and studies with larger sample sizes will reveal the stage of morphological disruption during the development of embryos.

The use of new GAFCHROMIC EBT film for 125I seed dosimetry in Solid Water phantom.

PubMed

Chiu-Tsao, Sou-Tung; Medich, David; Munro, John

2008-08-01

Radiochromic film dosimetry has been extensively used for intravascular brachytherapy applications for near field within 1 cm from the sources. With the recent introduction of new model of radiochromic films, GAFCHROMIC EBT, with higher sensitivity than earlier models, it is promising to extend the distances out to 5 cm for low dose rate (LDR) source dosimetry. In this study, the use of new model GAFCHROMIC EBT film for 125I seed dosimetry in Solid Water was evaluated for radial distances from 0.06 cm out to 5 cm. A multiple film technique was employed for four 125I seeds (Implant Sciences model 3500) with NIST traceable air kerma strengths. Each experimental film was positioned in contact with a 125I seed in a Solid Water phantom. The products of the air kerma strength and exposure time ranged from 8 to 3158 U-h, with the initial air kerma strength of 6 U in a series of 25 experiments. A set of 25 calibration films each was sequentially exposed to one 125I seed at about 0.58 cm distance for doses from 0.1 to 33 Gy. A CCD camera based microdensitometer, with interchangeable green (520 nm) and red (665 nm) light boxes, was used to scan all the films with 0.2 mm pixel resolution. The dose to each 125I calibration film center was calculated using the air kerma strength of the seed (incorporating decay), exposure time, distance from seed center to film center, and TG43U1S1 recommended dosimetric parameters. Based on the established calibration curve, dose conversion from net optical density was achieved for each light source. The dose rate constant was determined as 0.991 cGy U(-1)h(-1) (+/-6.9%) and 1.014 cGy U(-1)h(-1) (+/-6.8%) from films scanned using green and red light sources, respectively. The difference between these two values was within the uncertainty of the measurement. Radial dose function and 2D anisotropy function were also determined. The results obtained using the two light sources corroborated each other. We found good agreement with the TG43U1S1 recommended values of radial dose function and 2D anisotropy function, to within the uncertainty of the measurement. We also verified the dosimetric parameters in the near field calculated by Rivard using Monte Carlo method. The radial dose function values in Solid Water were lower than those in water recommended by TG43U1S1, by about 2%, 3%, 7%, and 14% at 2, 3, 4, and 5 cm, respectively, partially due to the difference in the phantom material composition. Radiochromic film dosimetry using GAFCHROMIC EBT model is feasible in determining 2D dose distributions around low dose rate 125I seed. It is a viable alternative to TLD dosimetry for 125I seed dose characterization.

Sae regulator factor impairs the response to photodynamic inactivation mediated by Toluidine blue in Staphylococcus aureus.

PubMed

Gándara, Lautaro; Mamone, Leandro; Dotto, Cristian; Buzzola, Fernanda; Casas, Adriana

2016-12-01

Photodynamic inactivation (PDI) involves the combined use of light and a photosensitizer, which, in the presence of oxygen, originates cytotoxic species capable of inactivating bacteria. Since the emergence of multi-resistant bacterial strains is becoming an increasing public health concern, PDI becomes an attractive choice. The aim of this work was to study the differential susceptibility to Toluidine blue (TB) mediated PDI (TB-PDI) of S. aureus mutants (RN6390 and Newman backgrounds) for different key regulators of virulence factors related to some extent to oxidative stress. Complete bacteria eradication of planktonic cultures of RN6390 S. aureus photosensitized with 13μM TB was obtained upon illumination with a low light dose of 4.2J/cm 2 from a non-coherent light source. Similarly, complete cell death was achieved applying 1.3μM TB and 19J/cm 2 light dose, showing that higher light doses can lead to equal cell death employing low photosensitizer concentrations. Interestingly, RN6390 in planktonic culture responded significantly better to TB-PDI than the Newman strain. We showed that deficiencies in rsbU, mgrA (transcription factors related to stress response) or agr (quorum sensing system involved in copper resistance to oxidative stress) did not modify the response of planktonic S. aureus to PDI. On the other hand, the two component system sae impaired the response to TB-PDI through a mechanism not related to the Eap adhesin. More severe conditions were needed to inactivate S. aureus biofilms (0.5mM TB, 157J/cm 2 laser light). In mutant sae biofilms, strain dependant differential susceptibilities are not noticed. Copyright © 2016 Elsevier B.V. All rights reserved.

Lethal photosensitization of periodontal pathogens by a red-filtered Xenon lamp in vitro.

PubMed

Matevski, Donco; Weersink, Robert; Tenenbaum, Howard C; Wilson, Brian; Ellen, Richard P; Lépine, Guylaine

2003-08-01

The ability of Helium-Neon (He-Ne) laser irradiation of a photosensitizer to induce localized phototoxic effects that kill periodontal pathogens is well documented and is termed photodynamic therapy (PDT). We investigated the potential of a conventional light source (red-filtered Xenon lamp) to activate toluidine blue O (TBO) in vitro and determined in vitro model parameters that may be used in future in vivo trials. Porphyromonas gingivalis 381 was used as the primary test bacterium. Treatment with a 2.2 J/cm2 light dose and 50 micro g/ml TBO concentration resulted in a bacterial kill of 2.43 +/- 0.39 logs with the He-Ne laser control and 3.34 +/- 0.24 logs with the lamp, a near 10-fold increase (p = 0.028). Increases in light intensity produced significantly higher killing (p = 0.012) that plateaued at 25 mW/cm2. There was a linear relationship between light dose and bacterial killing (r2 = 0.916); as light dose was increased bacterial survival decreased. No such relationship was found for the drug concentrations tested. Addition of serum or blood at 50% v/v to the P. gingivalis suspension prior to irradiation diminished killing from approximately 5 logs to 3 logs at 10 J/cm2. When serum was washed off, killing returned to 5 logs for all species tested except Bacteroides forsythus (3.92 +/- 0.68 logs kill). The data indicate that PDT utilizing a conventional light source is at least as effective as laser-induced treatment in vitro. Furthermore, PDT achieves significant bactericidal activity in the presence of serum and blood when used with the set parameters of 10 J/cm2, 100 mW/cm2 and 12.5 micro g/ml TBO.

Effect of Light on Anthocyanin Levels in Submerged, Harvested Cranberry Fruit

PubMed Central

Singh, Bal Ram

2004-01-01

Anthocyanins are a group of plant antioxidants known for their therapeutic use. The effects of natural light, red light, and far-red light on individual as well as total anthocyanin content in cranberry fruit (Vaccinium macrocarpon Ait) were examined in an experimental setting designed to mimic water-harvesting conditions. The reversed-phase high-performance liquid chromatography (HPLC) method was used to separate and analyze the anthocyanins. In contrast to the case of the control sample that was kept in the dark, natural light increased the total anthocyanin level by 75.3% and 87.2% after 24 and 48 hours of water immersion, respectively. Red light and far-red light increased the total anthocyanin level by 41.5% and 34.7%, respectively. The amount of each individual anthocyanin increased differently under natural light, red light, and far-red light, suggesting that expressions of enzymes that catalyze the anthocyanin biosynthesis are regulated differently by environments. PMID:15577187

Long-term erythemal UV doses at Sodankylä estimated using total ozone, sunshine duration, and snow depth

NASA Astrophysics Data System (ADS)

Lindfors, A. V.; Arola, A.; Kaurola, J.; Taalas, P.; SvenøE, T.

2003-08-01

A method for estimating daily erythemal UV doses using total ozone, sunshine duration, and snow depth has been developed. The method consists of three steps: (1) daily clear-sky UV doses were simulated using the UVSPEC radiative transfer program, with daily values of total ozone as input data, (2) an empirical relationship was sought between the simulated clear-sky UV doses, the measured UV doses, and the duration of bright sunshine, and (3) daily erythemal UV doses were estimated using this relationship. The method accounts for the varying surface albedo by dividing the period of interest into winter and summer days, depending on the snow depth. Using this method, the daily erythemal UV doses at Sodankylä were estimated for the period 1950-1999. This was done using Tromsø's total ozone together with Sodankylä's own sunshine duration and snow depth as input data. Although the method is fairly simple, the results are in good agreement, even on the daily scale, with the UV radiation measured with the Brewer spectrophotometer at Sodankylä. Over the period 1950-1999 a statistically significant increasing trend of 3.9% per decade in erythemal UV doses was found for March. The fact that this trend is much more pronounced during the latter part of the period, which is also the case for April, suggests a connection to the stratospheric ozone depletion. For July, on the other hand, a significant decreasing trend of 3.3% per decade, supported by the changes in both total ozone and sunshine duration, was found.

Safety of an ED High-Dose Opioid Protocol for Sickle Cell Disease Pain.

PubMed

Tanabe, Paula; Martinovich, Zoran; Buckley, Barbara; Schmelzer, Annie; Paice, Judith A

2015-05-01

A nurse-initiated high dose, opioid protocol for vaso-occlusive crisis (VOC) was implemented. Total intravenous morphine sulfate equivalents (IVMSE) in mgs] and safety was evaluated. A medical record review was conducted for all ED visits in adult patients with VOC post protocol implementation. Opioids doses and routes administered during the ED stay, and six hours into the hospital admission were abstracted and total IVMSE administered calculated. Oxygen saturation (SPO2), respiratory rate (RR), administration of naloxone or vasoactive medications, evidence of respiratory arrest, or any other types of resuscitation effort were abstracted. A RR of <10 or SPO2 <92% were coded as abnormal. Descriptive statistics report the total dose. Logistic regression was used to predict abnormal events. Predictors were age, gender, ED dose (10 mg increments) administered, and time from 1st dose to discharge from ED. 72 patients, 603 visits, 276 admitted. The total (ED & hospital dose) mean (95% CI) mg IVMSE administered for all visits was 93 mg (CI 86, 100), ED visit 63 mg (CI 59, 67) and hospital 66 mg (CI 59, 72). The mean (SD) time from administration of 1st analgesic dose to discharge from the ED was 203 (143) minutes, (range = 30-1396 minutes). During two visits, patients experienced a RR <10; while 61 visits were associated with a SPO2 <92%. No medications were administered, or resuscitative measures required. Controlling for demographics and evaluated at the average total ED dose, the longer patients were in the ED, patients were 1.359 times more likely to experience an abnormal vital sign. Controlling for demographics and evaluated at the average total time in the ED, for every 10 mg increase in IVMSE, patients were 1.057 times more likely to experience an abnormal vital sign. The effect of ED dose on the odds of experiencing an abnormal vital sign decreased by a multiplicative factor of 0.0970 for every 1 hour increase in time until discharge. The larger the dose administered in less time, the more likely patients experienced an abnormal vital sign. High opioid doses were safely administered to patients with sickle cell disease. Copyright © 2015 Emergency Nurses Association. Published by Elsevier Inc. All rights reserved.

The dark art of light measurement: accurate radiometry for low-level light therapy.

PubMed

Hadis, Mohammed A; Zainal, Siti A; Holder, Michelle J; Carroll, James D; Cooper, Paul R; Milward, Michael R; Palin, William M

2016-05-01

Lasers and light-emitting diodes are used for a range of biomedical applications with many studies reporting their beneficial effects. However, three main concerns exist regarding much of the low-level light therapy (LLLT) or photobiomodulation literature; (1) incomplete, inaccurate and unverified irradiation parameters, (2) miscalculation of 'dose,' and (3) the misuse of appropriate light property terminology. The aim of this systematic review was to assess where, and to what extent, these inadequacies exist and to provide an overview of 'best practice' in light measurement methods and importance of correct light measurement. A review of recent relevant literature was performed in PubMed using the terms LLLT and photobiomodulation (March 2014-March 2015) to investigate the contemporary information available in LLLT and photobiomodulation literature in terms of reporting light properties and irradiation parameters. A total of 74 articles formed the basis of this systematic review. Although most articles reported beneficial effects following LLLT, the majority contained no information in terms of how light was measured (73%) and relied on manufacturer-stated values. For all papers reviewed, missing information for specific light parameters included wavelength (3%), light source type (8%), power (41%), pulse frequency (52%), beam area (40%), irradiance (43%), exposure time (16%), radiant energy (74%) and fluence (16%). Frequent use of incorrect terminology was also observed within the reviewed literature. A poor understanding of photophysics is evident as a significant number of papers neglected to report or misreported important radiometric data. These errors affect repeatability and reliability of studies shared between scientists, manufacturers and clinicians and could degrade efficacy of patient treatments. Researchers need a physicist or appropriately skilled engineer on the team, and manuscript reviewers should reject papers that do not report beam measurement methods and all ten key parameters: wavelength, power, irradiation time, beam area (at the skin or culture surface; this is not necessarily the same size as the aperture), radiant energy, radiant exposure, pulse parameters, number of treatments, interval between treatments and anatomical location. Inclusion of these parameters will improve the information available to compare and contrast study outcomes and improve repeatability, reliability of studies.

SU-E-J-17: A Study of Accelerator-Induced Cerenkov Radiation as a Beam Diagnostic and Dosimetry Tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bateman, F; Tosh, R

2014-06-01

Purpose: To investigate accelerator-induced Cerenkov radiation imaging as a possible beam diagnostic and medical dosimetry tool. Methods: Cerenkov emission produced by clinical accelerator beams in a water phantom was imaged using a camera system comprised of a high-sensitivity thermoelectrically-cooled CCD camera coupled to a large aperture (f/0.75) objective lens with 16:1 magnification. This large format lens allows a significant amount of the available Cerenkov light to be collected and focused onto the CCD camera to form the image. Preliminary images, obtained with 6 MV photon beams, used an unshielded camera mounted horizontally with the beam normal to the water surface,more » and confirmed the detection of Cerenkov radiation. Several improvements were subsequently made including the addition of radiation shielding around the camera, and altering of the beam and camera angles to give a more favorable geometry for Cerenkov light collection. A detailed study was then undertaken over a range of electron and photon beam energies and dose rates to investigate the possibility of using this technique for beam diagnostics and dosimetry. Results: A series of images were obtained at a fixed dose rate over a range of electron energies from 6 to 20 MeV. The location of maximum intensity was found to vary linearly with the energy of the beam. A linear relationship was also found between the light observed from a fixed point on the central axis and the dose rate for both photon and electron beams. Conclusion: We have found that the analysis of images of beam-induced Cerenkov light in a water phantom has potential for use as a beam diagnostic and medical dosimetry tool. Our future goals include the calibration of the light output in terms of radiation dose and development of a tomographic system for 3D Cerenkov imaging in water phantoms and other media.« less

Metal-based phthalocyanines as a potential photosensitizing agent in photodynamic therapy for the treatment of melanoma skin cancer

NASA Astrophysics Data System (ADS)

Maduray, Kaminee; Odhav, B.

2014-03-01

Photodynamic therapy (PDT) is an emerging medical treatment that uses photosensitizers (drug) which are activated by laser light for the generation of cytotoxic free radicals and singlet oxygen molecules that cause tumor cell death. In the recent years, there has been a focus on using and improving an industrial colorant termed phthalocyanines as a prospective photosensitizer because of its unique properties. This in vitro study investigated the photodynamic effect of indium (InPcCl) and iron (FePcCl) phthalocyanine chlorides on human skin cancer cells (melanoma). Experimentally, 2 x 104 cells/ml were seeded in 24-well tissue culture plates and allowed to attach overnight, after which cells were treated with different concentrations (2 μg/ml - 100 μg/ml) of InPcCl and FePcCl. After 2 h, cells were irradiated with constant light doses of 2.5 J/cm2, 4.5 J/cm2 and 8.5 J/cm2 delivered from a diode laser. Post-irradiated cells were incubated for 24 h before cell viability was measured using the MTT Assay. At 24 h after PDT, irradiation with a light dose of 2.5 J/cm2 for each photosensitizing concentration of InPcCl and FePcCl produced a significant decrease in cell viability, but when the treatment light dose was further increased to 4.5 J/cm2 and 8.5 J/cm2 the cell survival was less than 55% for photosensitizing concentrations of InPcCl and FePcCl from 4 μg/ml to 100 μg/ml. This PDT study concludes that low concentrations on InPcCl and FePcCl activated with low level light doses can be used for the effective in vitro killing of melanoma cancer cells.

Photo-activated disinfection based on indocyanine green against cell viability and biofilm formation of Porphyromonas gingivalis.

PubMed

Pourhajibagher, Maryam; Chiniforush, Nasim; Ghorbanzadeh, Roghayeh; Bahador, Abbas

2017-03-01

Photo-activated disinfection (PAD) is a novel treatment approach, in which bacteria in the root canal system may be exposed to sub-lethal doses of PAD. Such exposure can affect bacterial survival and virulence features, such as biofilm formation ability. The aim of this study was to evaluate the effects of sub-lethal doses of PAD (sPAD) using indocyanine green (ICG) on load and biofilm formation ability of Porphyromonas gingivalis as an anaerobic bacterium associated with endodontic infection. The anti-bacterial and anti-biofilm potential of sPAD against P. gingivalis at sub-lethal doses of ICG as a photosensitizer and using 810nm wavelength of diode laser light via colony forming unit and crystal violet assays, respectively, was determined. High concentrations of ICG and light irradiation time significantly reduced bacteria. High doses of sPAD markedly reduced the number of bacteria and the formation of biofilm, up to 30.4% and 25.1%, respectively. High doses of sPAD affected cell viability and the biofilm formation ability of P. gingivalis; lower doses did not. Thus, selection of appropriate PAD dosage should be considered for the successful treatment of endodontic in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

Oral Tranexamic Acid Reduces Transfusions in Total Knee Arthroplasty.

PubMed

Perreault, Roger E; Fournier, Christine A; Mattingly, David A; Junghans, Richard P; Talmo, Carl T

2017-10-01

Tranexamic acid (TXA) reduces intraoperative blood loss and transfusions in patients undergoing total knee arthroplasty. Although numerous studies demonstrate the efficacy of intravenous and topical TXA in these patients, few demonstrate the effectiveness and appropriate dosing recommendations of oral formulations. A retrospective cohort study was performed to evaluate differences in transfusion requirements in patients undergoing primary unilateral total knee arthroplasty with either no TXA (n = 866), a single-dose of oral TXA (n = 157), or both preoperative and postoperative oral TXA (n = 1049). Secondary outcomes included postoperative hemoglobin drop, total units transfused, length of stay, drain output, and cell salvage volume. Transfusion rates decreased from 15.4% in the no-oral tranexamic acid (OTA) group to 9.6% in the single-dose OTA group (P < .001) and 7% in the 2-dose group (P < .001), with no difference in transfusion rates between the single- and 2-dose groups (P = .390). In addition, postoperative hemoglobin drop was reduced from 4.2 g/dL in the no-OTA group to 3.5 g/dL in the single-dose group (P < .01) and to 3.4 g/dL in the 2-dose group (P < .01), without a difference between the single- and 2-dose groups (P = .233). OTA reduces transfusions, with greater ease of administration and improved cost-effectiveness relative to other forms of delivery. Copyright © 2017 Elsevier Inc. All rights reserved.

High dose psilocybin is associated with positive subjective effects in healthy volunteers.

PubMed

Nicholas, Christopher R; Henriquez, Kelsey M; Gassman, Michele C; Cooper, Karen M; Muller, Daniel; Hetzel, Scott; Brown, Randall T; Cozzi, Nicholas V; Thomas, Chantelle; Hutson, Paul R

2018-06-01

The aim of the current study was to investigate the relationship between escalating higher doses of psilocybin and the potential psilocybin occasioned positive subjective effects. Healthy participants ( n=12) were given three escalating doses of oral psilocybin (0.3 mg/kg; 0.45 mg/kg; 0.6 mg/kg) or (18.8-36.6 mg; 27.1-54.0 mg; 36.3-59.2 mg) a minimum of four weeks apart in a supervised setting. Blood and urine samples, vital signs, and electrocardiograms were obtained. Subjective effects were assessed using the Mystical Experience Questionnaire and Persisting Effects Questionnaire. There was a significant linear dose-related response in Mystical Experience Questionnaire total score and the transcendence of time and space subscale, but not in the rate of a complete mystical experience. There was also a significant difference between dose 3 compared to dose 1 on the transcendence of time and space subscale, while no dose-related differences were found for Mystical Experience Questionnaire total scores or rate of a mystical experience. Persisting Effects Questionnaire positive composite scores 30 days after completion of the last dose were significantly higher than negative composite scores. Persisting Effects Questionnaire results revealed a moderate increase in sense of well-being or life satisfaction on average that was associated with the maximum Mystical Experience Questionnaire total score. Pharmacokinetic measures were associated with dose but not with Mystical Experience Questionnaire total scores or rate of a mystical experience. High doses of psilocybin elicited subjective effects at least as strong as the lower doses and resulted in positive persisting subjective effects 30 days after, indicating that a complete mystical experience was not a prerequisite for positive outcomes.

Enhancement of SV40 transformation by treatment of C3H2K cells with uv light and caffeine. I. Combined effect of uv light and caffeine. [Mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ide, T.; Anzai, K.; Andoh, T.

1975-08-01

Treatment of cultured mouse cells, C3H2K, with uv light and/or caffeine enhanced the frequency of SV40-induced transformation. This enhancement depends upon the doses of uv and caffeine and the mode of combination of these agents. Irradiation of cells with increasing doses of uv just before infection resulted in approximately 2-fold enhancement of the transformation frequency up to a dose of 90 ergs/mm/sup 2/ and 3.3-fold at 150 ergs/mm/sup 2/. Addition of 1 mM caffeine to the medium for 4 days subsequent to infection brought about a 2-fold enhancement. When cells were irradiated and treated with 1 mM caffeine, the enhancementmore » was approximately 4-fold up to a uv dose of 90 ergs/mm/sup 2/ and 5.9-fold at 150 ergs/mm/sup 2/. When 0.1 to 4 mM caffeine was added for 4 days postinfection, the absolute number of transformations increased, and an enhancement ratio of 1.3 to 6.8 resulted. After the addition of the same increasing doses of caffeine to uv-irradiated cells (75 ergs/mm/sup 2/), the enhancement of transformation frequency was even higher ranging 2.0 to 13.3. The transformation frequencies thus obtained by the double treatment were always higher than those predicted if uv and caffeine acted additively. The transformation frequency was little affected by the addition of dibutyrylcyclic AMP and theophylline.« less

Dengue and chikungunya viruses in plasma are effectively inactivated after treatment with methylene blue and visible light.

PubMed

Fryk, Jesse J; Marks, Denese C; Hobson-Peters, Jody; Prow, Natalie A; Watterson, Daniel; Hall, Roy A; Young, Paul R; Reichenberg, Stefan; Sumian, Chryslain; Faddy, Helen M

2016-09-01

Arboviruses, such as dengue viruses (DENV) and chikungunya virus (CHIKV), pose a risk to the safe transfusion of blood components, including plasma. Pathogen inactivation is an approach to manage this transfusion transmission risk, with a number of techniques being used worldwide for the treatment of plasma. In this study, the efficacy of the THERAFLEX MB-Plasma system to inactivate all DENV serotypes (DENV-1, DENV-2, DENV-3, DENV-4) or CHIKV in plasma, using methylene blue and light illumination at 630 nm, was investigated. Pooled plasma units were spiked with DENV-1, DENV-2, DENV-3 DENV-4, or CHIKV and treated with the THERAFLEX MB-Plasma system at four light illumination doses: 20, 40, 60, and 120 (standard dose) J/cm(2) . Pre- and posttreatment samples were collected and viral infectivity was determined. The reduction in viral infectivity was calculated for each dose. Treatment of plasma with the THERAFLEX MB-Plasma system resulted in at least a 4.46-log reduction in all DENV serotypes and CHIKV infectious virus. The residual infectivity for each was at the detection limit of the assay used at 60 J/cm(2) , with dose dependency also observed. Our study demonstrated the THERAFLEX MB-Plasma system can reduce the infectivity of all DENV serotypes and CHIKV spiked into plasma to the detection limit of the assay used at half of the standard illumination dose. This suggests this system has the capacity to be an effective option for managing the risk of DENV or CHIKV transfusion transmission in plasma. © 2016 AABB.

Correlation of different spectral lights with biomass accumulation and production of antioxidant secondary metabolites in callus cultures of medicinally important Prunella vulgaris L.

PubMed

Fazal, Hina; Abbasi, Bilal Haider; Ahmad, Nisar; Ali, Syed Shujait; Akbar, Fazal; Kanwal, Farina

2016-06-01

Light is one of the key elicitors that directly fluctuates plant developmental processes and biosynthesis of secondary metabolites. In this study, the effects of various spectral lights on biomass accumulation and production of antioxidant secondary metabolites in callus cultures of Prunella vulgaris were investigated. Among different spectral lights, green light induced the maximum callogenic response (95%). Enhanced fresh biomass accumulation was observed in log phases on day-35, when callus cultures were exposed to yellow and violet lights. Yellow light induced maximum biomass accumulation (3.67g/100ml) from leaf explants as compared to control (1.27g/100ml). In contrast, violet lights enhanced biomass accumulation (3.49g/100ml) from petiole explant. Maximum total phenolics content (TPC; 23.9mg/g-DW) and total flavonoids content (TFC; 1.65mg/g-DW) were observed when cultures were grown under blue lights. In contrast, green and yellow lights enhanced total phenolics production (TPP; 112.52g/100ml) and total flavonoids production (TFP; 9.64g/100ml) as compared to control. The calli grown under green, red and blue lights enhanced DPPH-free radical scavenging activity (DFRSA; 91.3%, 93.1% and 93%) than control (56.44%) respectively. The DFRSA was correlated either with TPC and TFC or TPP and TFP. Furthermore, yellow lights enhanced superoxide dismutase (SOD), peroxidase (POD) and protease activities, however, the content of total protein (CTP) was higher in control cultures (186μg BSAE/mg FW) as compared to spectral lights. These results suggest that the exposure of callus cultures to various spectral lights have shown a key role in biomass accumulation and production of antioxidant secondary metabolites. Copyright © 2016 Elsevier B.V. All rights reserved.

Violet/blue light activates Nrf2 signaling and modulates the inflammatory response of THP-1 monocytes.

PubMed

Trotter, L A; Patel, D; Dubin, S; Guerra, C; McCloud, V; Lockwood, P; Messer, R; Wataha, J C; Lewis, J B

2017-06-14

Several studies suggest that light in the UVA range (320-400 nm) activates signaling pathways that are anti-inflammatory and antioxidative. These effects have been attributed to Nrf2-mediated upregulation of "phase 2" genes such as heme oxygenase-1 (HO-1) that neutralize oxidative stress and metabolize electrophiles. Proteomics analysis previously had shown that small doses of blue light (400-500 nm) increased levels of peroxiredoxin phase 2 proteins in THP-1 monocytes, which led to our hypothesis that blue light activates Nrf2 signaling and thus may serve as an anti-inflammatory agent. THP-1 monocytes were treated with doses of blue light with and without lipopolysaccharide (LPS) inflammatory challenge. Cell lysates were tested for Nrf2 activation and HO-1 production. Treated cells were assessed for viability/mitochondrial activity via trypan blue exclusion and MTT assay, and secretion of two major pro-inflammatory cytokines, interleukin 8 (IL8) and tumor necrosis factor alpha (TNFα) was measured using ELISA. Blue light activated the phase 2 response in cultured THP-1 cells and was protective against LPS-induced cytotoxicity. Light pre-treatment also significantly reduced cytokine secretion in response to 0.1 μg ml -1 LPS, but had no anti-inflammatory effect at high LPS levels. This study is the first to report these effects using a light source that is approved for routine use on dental patients. Cellular responses to these light energies are worth further study and may provide therapeutic interventions for inflammation.

Method for detecting radiation dose utilizing thermoluminescent material

DOEpatents

Miller, Steven D.; McDonald, Joseph C.; Eichner, Fred N.; Durham, James S.

1992-01-01

The amount of ionizing radiation to which a thermoluminescent material has been exposed is determined by first cooling the thermoluminescent material and then optically stimulating the thermoluminescent material by exposure to light. Visible light emitted by the thermoluminescent material as it is allowed to warm up to room temperature is detected and counted. The thermoluminescent material may be annealed by exposure to ultraviolet light.

Method for detecting radiation dose utilizing thermoluminescent material

DOEpatents

Miller, S.D.; McDonald, J.C.; Eichner, F.N.; Durham, J.S.

1992-08-04

The amount of ionizing radiation to which a thermoluminescent material has been exposed is determined by first cooling the thermoluminescent material and then optically stimulating the thermoluminescent material by exposure to light. Visible light emitted by the thermoluminescent material as it is allowed to warm up to room temperature is detected and counted. The thermoluminescent material may be annealed by exposure to ultraviolet light. 5 figs.

Controlled-release systemic delivery - a new concept in cancer chemoprevention

PubMed Central

2012-01-01

Many chemopreventive agents have encountered bioavailability issues in pre-clinical/clinical studies despite high oral doses. We report here a new concept utilizing polycaprolactone implants embedded with test compounds to obtain controlled systemic delivery, circumventing oral bioavailability issues and reducing the total administered dose. Compounds were released from the implants in vitro dose dependently and for long durations (months), which correlated with in vivo release. Polymeric implants of curcumin significantly inhibited tissue DNA adducts following the treatment of rats with benzo[a]pyrene, with the total administered dose being substantially lower than typical oral doses. A comparison of bioavailability of curcumin given by implants showed significantly higher levels of curcumin in the plasma, liver and brain 30 days after treatment compared with the dietary route. Withaferin A implants resulted in a nearly 60% inhibition of lung cancer A549 cell xenografts, but no inhibition occurred when the same total dose was administered intraperitoneally. More than 15 phytochemicals have been tested successfully by this formulation. Together, our data indicate that this novel implant-delivery system circumvents oral bioavailability issues, provides continuous delivery for long durations and lowers the total administered dose, eliciting both chemopreventive/chemotherapeutic activities. This would also allow the assessment of activity of minor constituents and synthetic metabolites, which otherwise remain uninvestigated in vivo. PMID:22696595

Excess of Radiation Burden for Young Testicular Cancer Patients using Automatic Exposure Control and Contrast Agent on Whole-body Computed Tomography Imaging.

PubMed

Niiniviita, Hannele; Kulmala, Jarmo; Pölönen, Tuukka; Määttänen, Heli; Järvinen, Hannu; Salminen, Eeva

2017-06-01

The aim of the study was to assess patient dose from whole-body computed tomography (CT) in association with patient size, automatic exposure control (AEC) and intravenous (IV) contrast agent. Sixty-five testicular cancer patients (mean age 28 years) underwent altogether 279 whole-body CT scans from April 2000 to April 2011. The mean number of repeated examinations was 4.3. The GE LightSpeed 16 equipped with AEC and the Siemens Plus 4 CT scanners were used for imaging. Whole-body scans were performed with (216) and without (63) IV contrast. The ImPACT software was used to determine the effective and organ doses. Patient doses were independent (p < 0.41) of patient size when the Plus 4 device (mean 7.4 mSv, SD 1.7 mSv) was used, but with the LightSpeed 16 AEC device, the dose (mean 14 mSv, SD 4.6 mSv) increased significantly (p < 0.001) with waist cirfumference. Imaging with the IV contrast agent caused significantly higher (13% Plus 4, 35% LightSpeed 16) exposure than non-contrast imaging (p < 0.001). Great caution on the use of IV contrast agent and careful set-up of the AEC modulation parameters is recommended to avoid excessive radiation exposure on the whole-body CT imaging of young patients.

Compendium of Total Ionizing Dose and Displacement Damage for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Boutte, Alvin J.; Chen, Dakai; Pellish, Jonathan A.; Ladbury, Raymond L.; Casey, Megan C.; Campola, Michael J.; Wilcox, Edward P.; Obryan, Martha V.; LaBel, Kenneth A.;

A simplified technique for delivering total body irradiation (TBI) with improved dose homogeneity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao Rui; Bernard, Damian; Turian, Julius

2012-04-15

Purpose: Total body irradiation (TBI) with megavoltage photon beams has been accepted as an important component of management for a number of hematologic malignancies, generally as part of bone marrow conditioning regimens. The purpose of this paper is to present and discuss the authors' TBI technique, which both simplifies the treatment process and improves the treatment quality. Methods: An AP/PA TBI treatment technique to produce uniform dose distributions using sequential collimator reductions during each fraction was implemented, and a sample calculation worksheet is presented. Using this methodology, the dosimetric characteristics of both 6 and 18 MV photon beams, including lungmore » dose under cerrobend blocks was investigated. A method of estimating midplane lung doses based on measured entrance and exit doses was proposed, and the estimated results were compared with measurements. Results: Whole body midplane dose uniformity of {+-}10% was achieved with no more than two collimator-based beam modulations. The proposed model predicted midplane lung doses 5% to 10% higher than the measured doses for 6 and 18 MV beams. The estimated total midplane doses were within {+-}5% of the prescribed midplane dose on average except for the lungs where the doses were 6% to 10% lower than the prescribed dose on average. Conclusions: The proposed TBI technique can achieve dose uniformity within {+-}10%. This technique is easy to implement and does not require complicated dosimetry and/or compensators.« less

How Long Can the Hubble Space Telescope Operate Reliably? A Total Dose Perspective

NASA Technical Reports Server (NTRS)

Xapsos, M. A.; Stauffer, C.; Jordan, T.; Poivey, C.; Haskins, D. N.; Lum, G.; Pergosky, A. M.; Smith, D. C.; LaBel, K. A.

2014-01-01

The Hubble Space Telescope has been at the forefront of discoveries in the field of astronomy for more than 20 years. It was the first telescope designed to be serviced in space and the last such servicing mission occurred in May 2009. The question of how much longer this valuable resource can continue to return science data remains. In this paper a detailed analysis of the total dose exposure of electronic parts at the box level is performed using solid angle sectoring/3-dimensional ray trace and Monte Carlo radiation transport simulations. Results are related to parts that have been proposed as possible total dose concerns. The spacecraft subsystem that appears to be at the greatest risk for total dose failure is identified. This is discussed with perspective on the overall lifetime of the spacecraft.

Role of N-Arachidonoyl-Serotonin (AA-5-HT) in Sleep-Wake Cycle Architecture, Sleep Homeostasis, and Neurotransmitters Regulation.

PubMed

Murillo-Rodríguez, Eric; Di Marzo, Vincenzo; Machado, Sergio; Rocha, Nuno B; Veras, André B; Neto, Geraldo A M; Budde, Henning; Arias-Carrión, Oscar; Arankowsky-Sandoval, Gloria

2017-01-01

The endocannabinoid system comprises several molecular entities such as endogenous ligands [anandamide (AEA) and 2-arachidonoylglycerol (2-AG)], receptors (CB 1 and CB 2 ), enzymes such as [fatty acid amide hydrolase (FAHH) and monoacylglycerol lipase (MAGL)], as well as the anandamide membrane transporter. Although the role of this complex neurobiological system in the sleep-wake cycle modulation has been studied, the contribution of the blocker of FAAH/transient receptor potential cation channel subfamily V member 1 (TRPV1), N -arachidonoyl-serotonin (AA-5-HT) in sleep has not been investigated. Thus, in the present study, varying doses of AA-5-HT (5, 10, or 20 mg/Kg, i.p.) injected at the beginning of the lights-on period of rats, caused no statistical changes in sleep patterns. However, similar pharmacological treatment given to animals at the beginning of the dark period decreased wakefulness (W) and increased slow wave sleep (SWS) as well as rapid eye movement sleep (REMS). Power spectra analysis of states of vigilance showed that injection of AA-5-HT during the lights-off period diminished alpha spectrum across alertness in a dose-dependent fashion. In opposition, delta power spectra was enhanced as well as theta spectrum, during SWS and REMS, respectively. Moreover, the highest dose of AA-5-HT decreased wake-related contents of neurotransmitters such as dopamine (DA), norepinephrine (NE), epinephrine (EP), serotonin (5-HT) whereas the levels of adenosine (AD) were enhanced. In addition, the sleep-inducing properties of AA-5-HT were confirmed since this compound blocked the increase in W caused by stimulants such as cannabidiol (CBD) or modafinil (MOD) during the lights-on period. Additionally, administration of AA-5-HT also prevented the enhancement in contents of DA, NE, EP, 5-HT and AD after CBD of MOD injection. Lastly, the role of AA-5-HT in sleep homeostasis was tested in animals that received either CBD or MOD after total sleep deprivation (TSD). The injection of CBD or MOD increased alertness during sleep rebound period after TSD. However, AA-5-HT blocked this effect by allowing animals to display an enhancement in sleep across sleep rebound period. Overall, our findings provide evidence that AA-5-HT is an important modulator of sleep, sleep homeostasis and neurotransmitter contents.

Dosimetric evaluation of total marrow irradiation using 2 different planning systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nalichowski, Adrian, E-mail: nalichoa@karmanos.org; Eagle, Don G.; Burmeister, Jay

This study compared 2 different treatment planning systems (TPSs) for quality and efficiency of total marrow irradiation (TMI) plans. The TPSs used in this study were VOxel-Less Optimization (VoLO) (Accuray Inc, Sunnyvale, CA) using helical dose delivery on a Tomotherapy Hi-Art treatment unit and Eclipse (Varian Medical Systems Inc, Palo Alto, CA) using volumetric modulated arc therapy (VMAT) dose delivery on a Varian iX treatment unit. A total dose of 1200 cGy was prescribed to cover 95% of the planning target volume (PTV). The plans were optimized and calculated based on a single CT data and structure set using themore » Alderson Rando phantom (The Phantom Laboratory, Salem, NY) and physician contoured target and organ at risk (OAR) volumes. The OARs were lungs, heart, liver, kidneys, brain, and small bowel. The plans were evaluated based on plan quality, time to optimize the plan and calculate the dose, and beam on time. The resulting mean and maximum doses to the PTV were 1268 and 1465 cGy for VoLO and 1284 and 1541 cGy for Eclipse, respectively. For 5 of 6 OAR structures the VoLO system achieved lower mean and D10 doses ranging from 22% to 52% and 3% to 44%, respectively. Total computational time including only optimization and dose calculation were 0.9 hours for VoLO and 3.8 hours for Eclipse. These times do not include user-dependent target delineation and field setup. Both planning systems are capable of creating high-quality plans for total marrow irradiation. The VoLO planning system was able to achieve more uniform dose distribution throughout the target volume and steeper dose fall off, resulting in superior OAR sparing. VoLO's graphics processing unit (GPU)–based optimization and dose calculation algorithm also allowed much faster creation of TMI plans.« less

Measurement and comparison of skin dose using OneDose MOSFET and Mobile MOSFET for patients with acute lymphoblastic leukemia

PubMed Central

Mattar, Essam H.; Hammad, Lina F.; Al-Mohammed, Huda I.

2011-01-01

Summary Background Total body irradiation is a protocol used to treat acute lymphoblastic leukemia in patients prior to bone marrow transplant. It is involved in the treatment of the whole body using a large radiation field with extended source-skin distance. Therefore measuring and monitoring the skin dose during the treatment is important. Two kinds of metal oxide semiconductor field effect transistor (OneDose MOSFET and mobile MOSEFT) dosimeter are used during the treatment delivery to measure the skin dose to specific points and compare it with the target prescribed dose. The objective of this study was to compare the variation of skin dose in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using OneDose MOSFET detectors and Mobile MOSFET, and then compare both results with the target prescribed dose. Material/Methods The measurements involved 32 patient’s (16 males, 16 females), aged between 14–30 years, with an average age of 22.41 years. One-Dose MOSFET and Mobile MOSFET dosimetry were performed at 10 different anatomical sites on every patient. Results The results showed there was no variation between skin dose measured with OneDose MOSFET and Mobile MOSFET in all patients. Furthermore, the results showed for every anatomical site selected there was no significant difference in the dose delivered using either OneDose MOSFET detector or Mobile MOSFET as compared to the prescribed dose. Conclusions The study concludes that One-Dose MOSFET detectors and Mobile MOSFET both give a direct read-out immediately after the treatment; therefore both detectors are suitable options when measuring skin dose for total body irradiation treatment. PMID:21709641

Measurement and comparison of skin dose using OneDose MOSFET and Mobile MOSFET for patients with acute lymphoblastic leukemia.

PubMed

Mattar, Essam H; Hammad, Lina F; Al-Mohammed, Huda I

2011-07-01

Total body irradiation is a protocol used to treat acute lymphoblastic leukemia in patients prior to bone marrow transplant. It is involved in the treatment of the whole body using a large radiation field with extended source-skin distance. Therefore measuring and monitoring the skin dose during the treatment is important. Two kinds of metal oxide semiconductor field effect transistor (OneDose MOSFET and mobile MOSEFT) dosimeter are used during the treatment delivery to measure the skin dose to specific points and compare it with the target prescribed dose. The objective of this study was to compare the variation of skin dose in patients with acute lymphatic leukemia (ALL) treated with total body irradiation (TBI) using OneDose MOSFET detectors and Mobile MOSFET, and then compare both results with the target prescribed dose. The measurements involved 32 patient's (16 males, 16 females), aged between 14-30 years, with an average age of 22.41 years. One-Dose MOSFET and Mobile MOSFET dosimetry were performed at 10 different anatomical sites on every patient. The results showed there was no variation between skin dose measured with OneDose MOSFET and Mobile MOSFET in all patients. Furthermore, the results showed for every anatomical site selected there was no significant difference in the dose delivered using either OneDose MOSFET detector or Mobile MOSFET as compared to the prescribed dose. The study concludes that One-Dose MOSFET detectors and Mobile MOSFET both give a direct read-out immediately after the treatment; therefore both detectors are suitable options when measuring skin dose for total body irradiation treatment.

Effect of Localizer Radiography Projection on Organ Dose at Chest CT with Automatic Tube Current Modulation.

PubMed

Saltybaeva, Natalia; Krauss, Andreas; Alkadhi, Hatem

2017-03-01

Purpose To calculate the effect of localizer radiography projections to the total radiation dose, including both the dose from localizer radiography and that from subsequent chest computed tomography (CT) with tube current modulation (TCM). Materials and Methods An anthropomorphic phantom was scanned with 192-section CT without and with differently sized breast attachments. Chest CT with TCM was performed after one localizer radiographic examination with anteroposterior (AP) or posteroanterior (PA) projections. Dose distributions were obtained by means of Monte Carlo simulations based on acquired CT data. For Monte Carlo simulations of localizer radiography, the tube position was fixed at 0° and 180°; for chest CT, a spiral trajectory with TCM was used. The effect of tube start angles on dose distribution was investigated with Monte Carlo simulations by using TCM curves with fixed start angles (0°, 90°, and 180°). Total doses for lungs, heart, and breast were calculated as the sum of the dose from localizer radiography and CT. Image noise was defined as the standard deviation of attenuation measured in 14 circular regions of interest. The Wilcoxon signed rank test, paired t test, and Friedman analysis of variance were conducted to evaluate differences in noise, TCM curves, and organ doses, respectively. Results Organ doses from localizer radiography were lower when using a PA instead of an AP projection (P = .005). The use of a PA projection resulted in higher TCM values for chest CT (P < .001) owing to the higher attenuation (P < .001) and thus resulted in higher total organ doses for all investigated phantoms and protocols (P < .001). Noise in CT images was lower with PA localizer radiography than with AP localizer radiography (P = .03). The use of an AP projection allowed for total dose reductions of 16%, 15%, and 12% for lungs, breast, and heart, respectively. Differences in organ doses were not related to tube start angles (P = .17). Conclusion The total organ doses are higher when using PA projection localizer radiography owing to higher TCM values, whereas the organ doses from PA localizer radiography alone are lower. Thus, PA localizer radiography should be used in combination with reduced reference tube current at subsequent chest CT. © RSNA, 2016 Online supplemental material is available for this article.

Development of light ion therapy at the Karolinska Hospital and Institute.

PubMed

Svensson, Hans; Ringborg, Ulrik; Näslund, Ingemar; Brahme, Anders

2004-12-01

Recent developments in radiation therapy have made it possible to optimize the high dose region to cover almost any target volume and shape at the same time as the dose level to adjacent organs at risk is acceptable. Further implementations of IMRT (Intensity Modulated Radiation Therapy), and inverse treatment planning using already available technologies but also foreseeable improved design of therapy accelerators delivering electron- and photon beams, will bring these advances to the benefit of a broad population of cancer patients. Protons will therefore generally not be needed since in most situations the improvement will be insignificant or moderate due to the large lateral penumbra with deep proton therapy. A further step would be to use He-ions, which have only half the penumbra width of protons and still a fairly low-LET in the spread-out Bragg peak. There is however still a group of patients that cannot be helped by these advances as the tumor might be radioresistant for the presently utilized low ionization density beam qualities. The ultimate step in the therapy development process should therefore be to optimize the beam quality for each tumor-normal tissue situation. To facilitate beam quality optimization light ions are needed. It is argued that in many radioresistant tumors a dose-mean LET of 25-50 eV/nm in the target would be optimum as then tumor cells will be lost in the highest proportion through apoptotic cell kill and the superficial tissues will still be irradiated with a fairly low LET. Light ions using Li, Be, B, and C would then be the ideal choice. In this paper a light ion facility is outlined for the Karolinska University Hospital facilitating both dose distribution and beam quality optimization.

Glycine inhibition of pupillary responses to pulses of light in conscious sheep.

PubMed

Seggie, J; Wright, N

1989-01-01

The use of a 1.5% glycine solution as a bladder irrigant during surgical removal of the prostate has been associated with transient visual impairment. Glycine is thought to be an inhibitory retinal transmitter. Adult female sheep were infused with a 1.5% glycine solution to provide a dose of 0, 7.5, 15, 30, or 60 g of glycine. The volume control was a solution of dextrose and saline. The degree of constriction of the pupil in response to 30 seconds of bright light following dilation in the dark was used as an index of visual response. Observations were made before and 2, 4, 6, 12, 24, 48, 96, and 192 hours after a single infusion. Significant inhibition of pupil response to light but not to the dark was apparent following systemically administered glycine resulting in plasma levels over 5000 mumol/L. Inhibition of pupil response was paralleled by behavioral indices of visual impairment but not by changes in plasma sodium, potassium, chloride or osmolality. The duration of the effect was dose dependent with visual impairment following a single high dose of glycine being detectable five days later and long after glycine levels had returned to normal. However, the relationship between dose, time, and effect appears to be complex. It is important to note that the present observations occurred at plasma glycine levels frequently experienced in routine surgical practice. The finding that significant long term detrimental effects of glycine could be detected should evoke a re-evaluation of the use of glycine as an irrigating solution for surgical procedures and stimulate further investigation of the effects of glycine on retinal function and the ability to perceive light.

Real time laser speckle imaging monitoring vascular targeted photodynamic therapy

NASA Astrophysics Data System (ADS)

Goldschmidt, Ruth; Vyacheslav, Kalchenko; Scherz, Avigdor

2017-02-01

Laser speckle imaging is a technique that has been developed to non-invasively monitor in vivo blood flow dynamics and vascular structure, at high spatial and temporal resolution. It can record the full-field spatio-temporal characteristics of microcirculation and has therefore, often been used to study the blood flow in tumors after photodynamic therapy (PDT). Yet, there is a paucity of reports on real-time laser speckle imaging (RTLSI) during PDT. Vascular-targeted photodynamic therapy (VTP) with WST11, a water-soluble bacteriochlorophyll derivative, achieves tumor ablation through rapid occlusion of the tumor vasculature followed by a cascade of events that actively kill the tumor cells. WST11-VTP has been already approved for treatment of early/intermediate prostate cancer at a certain drug dose, time and intensity of illumination. Application to other cancers may require different light dosage. However, incomplete vascular occlusion at lower light dose may result in cancer cell survival and tumor relapse while excessive light dose may lead to toxicity of nearby healthy tissues. Here we provide evidence for the feasibility of concomitant RTLSI of the blood flow dynamics in the tumor and surrounding normal tissues during and after WST11-VTP. Fast decrease in the blood flow is followed by partial mild reperfusion and a complete flow arrest within the tumor by the end of illumination. While the primary occlusion of the tumor feeding arteries and draining veins agrees with previous data published by our group, the late effects underscore the significance of light dose control to minimize normal tissue impairment. In conclusion- RTSLI application should allow to optimize VTP efficacy vs toxicity in both the preclinical and clinical arenas.

Butorphanol, azaperone, and medetomidine anesthesia in free-ranging white-tailed deer (Odocoileus virginianus) using radiotransmitter darts.

PubMed

Siegal-Willott, Jessica; Citino, Scott B; Wade, Scotty; Elder, Laura; Hayek, Lee-Ann C; Lance, William R

2009-04-01

Fourteen free-ranging white-tailed deer (Odocoileus virginianus) were successfully anesthetized for a total of 15 anesthetic events using a combination of butorphanol (mean+/-SD, 0.58+/-0.1 mg/kg), azaperone (0.37+/-0.06 mg/kg), and medetomidine (0.19+/-0.03 mg/kg) (BAM) administered by radiotelemetry darts from hunting blinds between November 2006 and May 2007. Mean time to locate deer (mean+/-SD, 17. 3+/-7 min), to recumbency (21.4+/-5 min), to initiation of data acquisition (27.5+/-8 min), total down time (37+/-6 min), and average distance run (161+/-82 m) were recorded. Physiologic monitoring was done every 5 min for a total of 20 min. Arterial blood gases were collected every 10 min. Mild to moderate hypoxemia and mildly depressed ventilation occurred in some animals. Muscle relaxation and plane of anesthesia were adequate for completion of all procedures; two deer were administered intravenous butorphanol supplementation to achieve light anesthesia (mean+/-SD, 0.19 mg/kg; 0.12 mg/kg). Recovery following intramuscular administration of naltrexone (1.34+/-0.42 mg/kg; 2x butorphanol dose) and atipamezole (0.93+/-0.14 mg/kg; 5x medetomidine dose) was rapid, smooth, and complete. Mean+/-SD recovery time was 4.5+/-1.5 min. Overall efficacy of the Pneu-Dart radiotelemetry system was 65%. Negative attributes of this protocol included long induction time and dart failure. No known mortalities occurred as a result of the study. This drug combination provided safe, reliable, short-term anesthesia of free-ranging white-tailed deer. Further evaluation for use in field procedures in other cervids is warranted.

Quantitative analysis of gold and carbon nanoparticles in mammalian cells by flow cytometry light scattering

NASA Astrophysics Data System (ADS)

Zhou, Gang; Liu, Naicheng; Wang, Zhenheng; Shi, Tongguo; Gan, Jingjing; Wang, Zhenzhen; Zhang, Junfeng

2017-02-01

Nanoparticle-based applications for diagnostics and therapeutics have been extensively studied. These applications require a profound understanding of the fate of nanoparticles (NPs) in cellular environments. However, until now, few analytical methods are available and most of them rely on fluorescent properties or special elements of NPs; therefore, for NPs without observable optical properties or special elements, the existing methods are hardly applicable. In this study, we introduce a flow cytometry light scattering (FCLS)-based approach that quantifies in situ NPs accurately in mammalian cells. Continuous cells of heterogeneous human epithelial colorectal adenocarcinoma (Caco-2 cells), mouse peritoneal macrophages (MPM), and human adenocarcinomic alveolar basal epithelia (A549 cells) were cultured with NPs with certain concentrations and size. The intensity of the flow cytometric side scattered light, which indicates the quantity of NPs in the cells, was analyzed. The result shows an accurate size- and dose-dependent uptake of Au NPs (5, 30, 250 nm) in Caco-2 cells. The size- and dose- dependence of Au NPs (5, 30, 250 nm) and carbon NPs (50, 500 nm) in cells was validated by transmission electron microscope (TEM). This paper demonstrates the great potential of flow cytometry light scattering in the quantitative study of the size and dose effect on in situ metallic or non-metallic NPs in mammalian cells.

Selective protection of cultured human cells from the toxic effects of ultraviolet light by proflavine pretreatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, J.R.; Little, J.B.

1977-10-01

Pretreatment of LICH human cells by nontoxic doses (0.1 to 5.0 ..mu..g/ml) of proflavine protects them from inactivation by ultraviolet light. The protection is acquired rapidly after exposure of cells to proflavine, with 50 percent of maximum protection being afforded within 5 min and cells being maximally protected by 20 min. Loss of protection follows similar kinetics upon removal of proflavine from the culture medium. Protection is selective and cannot be explained on the basis of proflavine absorption of uv light. Cellular survival curves after ultraviolet light for cells protected by 1, 2, 3, 4, or 5 ..mu..g/ml of proflavinemore » show that protection alters only the slope of the survival curve, not altering the quasi-threshold dose, D/sub q/. The D/sub 0/ varies from 4.8 J/m/sup 2/ for untreated cells to 10.5 J/m/sup 2/ for cells pretreated with 5 ..mu..g/ml. These data suggest the D/sub 0/ and D/sub q/ do not represent parameters of a single underlying process, manifested in a random stochastic manner, but may reflect different cellular mechanisms or responses to different DNA damage. Proflavine is selective in mitigating only those which predominate at uv doses greater than the D/sub q/.« less

Total Ionizing Dose Test of Microsemi's Silicon Switching Transistors JANTXV2N2222AUB and 2N2907AUB

NASA Technical Reports Server (NTRS)

Campola, M.; Freeman, B.; Yau, K.

2017-01-01

Microsemi's silicon switching transistors, JANTXV2N2222AUB and 2N2907AUB, were tested for total ionizing dose (TID) response beginning on July 11, 2016. This test served as the radiation lot acceptance test (RLAT) for the lot date code (LDC) tested. Low dose rate (LDR) irradiations were performed in this test so that the device susceptibility to enhanced low dose rate sensitivity (ELDRS) could be determined.

Polarized light improves cutaneous healing on diabetic rats

NASA Astrophysics Data System (ADS)

Ramalho, Luciana Maria Pedreira; Oliveira, Priscila Chagas; Marques, Aparecida Maria Cordeiro; Barbosa Pinheiro, Antonio L.

2010-02-01

The aim of this study was to evaluate the healing of 3rd degree burn on diabetic rats submitted or not to treatment with Polarized Light. Diabetes mellitus (Streptozotocin, 60mg/kg) was induced on 45 male Wistar albinus rats and a third degree burn (1.5× 1.5cm) was created in the dorsum of each animal under general anesthesia. After a regular quarantine period, the animals were randomly distributed into three groups as follows: G1: control (no treatment, n =15); G2: Polarized Light (λ=400-2000nm, 20J/cm2) and G3: Polarized Light (λ=400-2000nm, 40J/cm2). The phototherapy performed on group G2 was Polarized Light dose 20J/cm2 and G3 was Polarized Light dose 40J/cm2 (Bioptron®, λ400-2000 nm, 40mW; 2.4J/cm2 per minute; Φ +/- 5.5 cm; Bioptron AG, Monchaltorf, Switzerland). The phototherapy started immediately post-burning and was repeated daily until the day before the animal death. The energy was applied transcutaneously respecting the focal distance of 10cm as recommended by the manufacturer. The dose was 20 or 40J/cm2 (4min 15s or 8min.and 30s). At each time point chosen (7, 14, and 21 days post-burning) and following macroscopic examination, each animal was killed by an overdose of general anesthesia. Slides were stained with HE, Sirius Red, and CK AE1/AE3 antibody. Qualitative and semi-quantitative analyses were performed under light microscopy. The animals submitted to phototherapy (20J/cm2) showed significant differences on regards revascularization and epithelialization. The use of 20J/cm2 was effective on improving the healing of third degree buns on diabetic animals at both early and late stages of the repair.

PBDE exposure from food in Ireland: optimising data exploitation in probabilistic exposure modelling.

PubMed

Trudel, David; Tlustos, Christina; Von Goetz, Natalie; Scheringer, Martin; Hungerbühler, Konrad

2011-01-01

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants added to plastics, polyurethane foam, electronics, textiles, and other products. These products release PBDEs into the indoor and outdoor environment, thus causing human exposure through food and dust. This study models PBDE dose distributions from ingestion of food for Irish adults on congener basis by using two probabilistic and one semi-deterministic method. One of the probabilistic methods was newly developed and is based on summary statistics of food consumption combined with a model generating realistic daily energy supply from food. Median (intermediate) doses of total PBDEs are in the range of 0.4-0.6 ng/kg(bw)/day for Irish adults. The 97.5th percentiles of total PBDE doses lie in a range of 1.7-2.2 ng/kg(bw)/day, which is comparable to doses derived for Belgian and Dutch adults. BDE-47 and BDE-99 were identified as the congeners contributing most to estimated intakes, accounting for more than half of the total doses. The most influential food groups contributing to this intake are lean fish and salmon which together account for about 22-25% of the total doses.

Irradiation for quarantine control of the invasive light brown apple moth, Epiphyas

USDA-ARS?s Scientific Manuscript database

The effects of irradiation on egg, larval, and pupal development, and adult reproduction in light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), were examined. Eggs, neonates, early instars, late instars, early pupae and late pupae were irradiated at target doses of 60, ...

EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOINDUCED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS

EPA Science Inventory

Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light received. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

THE EFFECT OF IRRADIANCE SPECTRA ON THE PHOTOACTIVATED TOXICITY OF THREE POLYCYCLIC AROMATIC HYDROCARBONS

EPA Science Inventory

Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) is dependent on the concentration of compounds present and the dose of light recieved. Of the light present, only those wavelengths absorbed by the compound have the potential to initiate the photochemical events un...

Low-Dose Topical 5-Aminolevulinic Acid Photodynamic Therapy in the Treatment of Different Severity of Acne Vulgaris.

PubMed

Tao, Shi-Qin; Li, Fei; Cao, Lei; Xia, Ru-Shan; Fan, Hua; Fan, Ying; Sun, Hui; Jing, Cheng; Yang, Li-Jia

2015-12-01

The objective of this article is to investigate the effectiveness and safety of photodynamic therapy (PDT) with 3.6 % topical aminolevulinic acid (ALA) and a short incubation time with red light in moderate to severe acne. One hundred and thirty-six patients with moderate to severe acne were treated with 3.6 % topical ALA-PDT for three sessions with an interval of 2 weeks. Patients were evaluated for efficacy and safety on week 2, 4, 6, 8, and 12 after the initial treatment. Most patients showed apparent clearance of acne lesions at the treated site after three sessions. The effective treatment rates were increased after the multiple therapies. The clinical outcomes are the best at 4 weeks after the final treatment. The total effectiveness rate and cure rate of the low-dose ALA-PDT procedure is 92.65 and 47.06 %, respectively. Thirty-one patients and nineteen patients showed apparent exacerbation of acne lesions before the 2nd and 3rd treatment, respectively, but all of them showed good or excellent improvement after a three-course treatment. A few patients showed mild relapse including papules and comedos at 8 weeks after the final treatment. No significant differences are found in the effects of different acne severity and different genders. Adverse reactions are mild and transient. A 3.6 % topical ALA-PDT with a short time incubation with red light is a simple and an effective treatment option for moderate to severe acne with mild side effects in Chinese people.

Human responses to bright light of different durations.

PubMed

Chang, Anne-Marie; Santhi, Nayantara; St Hilaire, Melissa; Gronfier, Claude; Bradstreet, Dayna S; Duffy, Jeanne F; Lockley, Steven W; Kronauer, Richard E; Czeisler, Charles A

2012-07-01

Light exposure in the early night induces phase delays of the circadian rhythm in melatonin in humans. Previous studies have investigated the effect of timing, intensity, wavelength, history and pattern of light stimuli on the human circadian timing system. We present results from a study of the duration–response relationship to phase-delaying bright light. Thirty-nine young healthy participants (16 female; 22.18±3.62 years) completed a 9-day inpatient study. Following three baseline days, participants underwent an initial circadian phase assessment procedure in dim light (<3 lux), and were then randomized for exposure to a bright light pulse (∼10,000 lux) of 0.2 h, 1.0 h, 2.5 h or 4.0 h duration during a 4.5 h controlled-posture episode centred in a 16 h wake episode. After another 8 h sleep episode, participants completed a second circadian phase assessment. Phase shifts were calculated from the difference in the clock time of the dim light melatonin onset (DLMO) between the initial and final phase assessments. Exposure to varying durations of bright light reset the circadian pacemaker in a dose-dependent, non-linear manner. Per minute of exposure, the 0.2 h duration was over 5 times more effective at phase delaying the circadian pacemaker (1.07±0.36 h) as compared with the 4.0 h duration (2.65±0.24 h). Acute melatonin suppression and subjective sleepiness also had a dose-dependent response to light exposure duration. These results provide strong evidence for a non-linear resetting response of the human circadian pacemaker to light duration.

Total Ionizing Dose and Displacement Damage Compendium of Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Chen, Dakai; Oldham, Timothy R.; Sanders, Anthony B.; Kim, Hak S.; Campola, Michael J.; Buchner, Stephen P.; LaBel, Kenneth A.; Marshall, Cheryl J.; Pellish, Jonathan A.;

The neuroprotective role of boric acid on aluminum chloride-induced neurotoxicity.

PubMed

Colak, Suat; Geyikoglu, Fatime; Keles, Osman Nuri; Türkez, Hasan; Topal, Ahmet; Unal, Bünyami

2011-09-01

This study was designed to investigate the qualitative and quantitative changes in brain tissue following aluminum chloride (AlCl(3)) administration and to determine whether boric acid (BA) has a protective effect against brain damage induced by AlCl( 3). For this aim, Sprague-Dawley rats were randomly separated into eight groups: (1) control, (2) AlCl(3) (5 mg/kg/day), (3, 4 and 5) BA (3.25, 36 and 58.5 mg/kg/day), (6, 7 and 8) AlCl(3) (5 mg/kg/day) plus BA (3.25, 36 and 58.5 mg/kg/day). After the animals were killed, the total numbers of neuron in the brain of all groups were determined using an unbiased stereological analysis. In addition to the stereological analysis, all brains were examined histopathologically by using light and electron microscopy. The stereological and histopathological results indicated a high damage of the rat brain tissues in the AlCl(3) and AlCl(3) + high dose BA (36 and 58.5) treatment groups. However, protective effects on neuron were observed in the AlCl(3) + low dose BA (3.25) group when compared other AlCl(3) groups. Our stereological and histopathological findings show that low-dose BA, as a proteasome inhibitor, can decrease the adverse effects of AlCl(3) on the cerebral cortex.

Clinical outcomes and cost minimization with an alternative dosing regimen for meropenem in a community hospital.

PubMed

Patel, Gita Wasan; Duquaine, Susan M; McKinnon, Peggy S

2007-12-01

To compare outcomes and cost for the traditional United States Food and Drug Administration-approved dosing regimen for meropenem versus an alternative dosing regimen providing similar pharmacodynamic exposure with a lower total daily dose. Retrospective cohort study with a cost-minimization analysis. A 417-bed, privately owned community hospital. One hundred patients who received meropenem 1 g every 8 or 12 hours (traditional dosing regimen) between January 1 and September 30, 2004 (historical controls), and 192 patients who received meropenem 500 mg every 6 or 8 hours (alternative dosing regimen) between October 1, 2004, and September 30, 2005. Demographic and clinical data were collected for all patients. Cost-minimization analysis was performed by using the drug acquisition cost for meropenem. Demographics, sources of infection, distributions of organisms, and Charlson Comorbidity Index scores were similar between patients in the traditionally and alternatively dosed groups. Concomitant therapy, duration of therapy, success rates, lengths of stay, and in-hospital mortality rates were also similar between groups. Median time to the resolution of symptoms was 3 days for traditional dosing and 1.5 days for alternative dosing (p<0.0001). A logistic regression model including the dosing strategy showed that only polymicrobial infections and sepsis were associated with increased failure rates. The median cost for antibiotics was $439.05/patient for traditional dosing and $234.08/patient for alternative dosing (p<0.0001). An alternative dosing regimen for meropenem with a lower total daily dose yielded patient outcomes, including success rates and duration of therapy, equivalent to those of the traditional dosing regimen. Alternative dosing decreased total drug exposure, costs for antibiotics, and time to the resolution of infections.

Effect of Direct-Fed Microbial Dosage on the Fecal Concentrations of Enterohemorrhagic Escherichia coli in Feedlot Cattle.

PubMed

Luedtke, Brandon E; Bosilevac, Joseph M; Harhay, Dayna M; Arthur, Terrance M

2016-04-01

Contamination of beef products by Shiga toxin-producing Escherichia coli is a concern for food safety with a particular subset, the enterohemorrhagic E. coli (EHEC), being the most relevant to human disease. To mitigate food safety risks, preharvest intervention strategies have been implemented with the aim to reduce EHEC in cattle. One class of interventions that has been widely used in feedlots is direct-fed microbials (DFMs), which can contain various dosing rates of probiotic bacteria. Here we compare the use of two different doses of a commercially available DFM on total EHEC load in a commercial feedlot setting. The DFMs used were the standard 10(9) Propionibacterium freudenreichii and 10(6) Lactobacillus acidophilus colony forming units (CFUs)/head/day dose of Bovamine(®) (Nutrition Physiology Company, Guymon, OK) and the higher dose, Bovamine Defend™ (Nutrition Physiology Company), which is dosed at 10(9) P. freudenreichii and 10(9) Lactobacillus acidophilus CFUs/head/day. To analyze the total EHEC fecal concentration, 2200 head of cattle were assigned a DFM feed regimen lasting approximately 5 months. At harvest, 480 head of cattle were sampled using rectoanal mucosal swabs. A quantitative polymerase chain reaction assay targeting ecf1 was used to enumerate the total EHEC fecal concentration for 240 head fed the low-dose DFM and 240 head fed the high-dose DFM. No significant difference (p > 0.05) in the fecal concentration of total EHEC was observed between the two doses. This suggests that using an increased dosage provides no additional reduction in the total EHEC fecal concentration of feedlot cattle compared to the standard dosage.

Patient dose analysis in total body irradiation through in vivo dosimetry.

PubMed

Ganapathy, K; Kurup, P G G; Murali, V; Muthukumaran, M; Bhuvaneshwari, N; Velmurugan, J

2012-10-01

Total body irradiation (TBI) is a special radiotherapy technique, administered prior to bone marrow transplantation. Due to the complex nature of the treatment setup, in vivo dosimetry for TBI is mandatory to ensure proper delivery of the intended radiation dose throughout the body. Lithium fluoride (LiF) TLD-100 chips are used for the TBI in vivo dosimetry. Results obtained from the in vivo dosimetry of 20 patients are analyzed. Results obtained from forehead, abdomen, pelvis, and mediastinum showed a similar pattern with the average measured dose from 96 to 97% of the prescription dose. Extremities and chest received a dose greater than the prescription dose in many instances (more than 20% of measurements). Homogeneous dose delivery to the whole body is checked by calculating the mean dose with standard deviation for each fraction. Reasons for the difference between prescription dose and measured dose for each site are discussed. Dose homogeneity within ±10% is achieved using our in-house TBI protocol.

Patient dose analysis in total body irradiation through in vivo dosimetry

PubMed Central

Ganapathy, K.; Kurup, P. G. G.; Murali, V.; Muthukumaran, M.; Bhuvaneshwari, N.; Velmurugan, J.

2012-01-01

Total body irradiation (TBI) is a special radiotherapy technique, administered prior to bone marrow transplantation. Due to the complex nature of the treatment setup, in vivo dosimetry for TBI is mandatory to ensure proper delivery of the intended radiation dose throughout the body. Lithium fluoride (LiF) TLD-100 chips are used for the TBI in vivo dosimetry. Results obtained from the in vivo dosimetry of 20 patients are analyzed. Results obtained from forehead, abdomen, pelvis, and mediastinum showed a similar pattern with the average measured dose from 96 to 97% of the prescription dose. Extremities and chest received a dose greater than the prescription dose in many instances (more than 20% of measurements). Homogeneous dose delivery to the whole body is checked by calculating the mean dose with standard deviation for each fraction. Reasons for the difference between prescription dose and measured dose for each site are discussed. Dose homogeneity within ±10% is achieved using our in-house TBI protocol. PMID:23293453

Studies of foetal death and foetal weight in guinea pigs fed polychlorinated biphenyls (PCB).

PubMed

Brunström, B; Kihlström, I; Lundkvist, U

1982-02-01

Pregnant guinea pigs were fed a total dose of 100 mg of the commercial PCB preparation Clophen A50 during days 16 to 60 of gestation. This treatment caused severe foetal, but no maternal, death. Contrarily, a total dose of 25 mg or 100 mg of 2,2',4,4',5,5'-hexachlorobiphenyl (HCB) did not cause foetal death in the guinea pig. The prenatal growth rate was increased by a total dose of 25 mg, but not by 100 mg, of HCB.

Population dose commitments due to radioactive releases from nuclear power plant sites in 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D.A.; Peloquin, R.A.

Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1980. In addition doses derived from the shutdown reactors at the Three Mile Island site were included. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showingmore » the fraction of the total population within 2 to 80 km around each site receiving various average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 40 person-rem to a low of 0.02 person-rem with an arithmetic mean of 4 person-rem. The total population dose for all sites was estimated at 180 person-rem for the 96 million people considered at risk.« less

Traffic-light labels could reduce population intakes of calories, total fat, saturated fat, and sodium

PubMed Central

Emrich, Teri E.; Qi, Ying; Lou, Wendy Y.; L’Abbe, Mary R.

2017-01-01

Traffic-light labelling has been proposed as a public health intervention to improve the dietary intakes of consumers. OBJECTIVES: to model the potential impact of avoiding foods with red traffic lights on the label on the energy, total fat, saturated fat, sodium, and sugars intakes of Canadian adults. METHODS: Canadian adults aged 19 and older (n = 19,915) who responded to the Canadian Community Health Survey (CCHS), Cycle 2.2. The nutrient levels in foods consumed by Canadians in CCHS were profiled using the United Kingdom’s criteria for traffic light labelling. Whenever possible, foods assigned a red traffic light for one or more of the profiled nutrients were replaced with a similar food currently sold in Canada, with nutrient levels not assigned any red traffic lights. Average intakes of calories, total fat, saturated fat, sodium, and sugars under the traffic light scenario were compared with actual intakes of calories and these nutrients (baseline) reported in CCHS. RESULTS: Under the traffic light scenario, Canadian’s intake of energy, total fat, saturated fat, and sodium were significantly reduced compared to baseline; sugars intakes were not significantly reduced. Calorie intake was reduced by 5%, total fat 13%, saturated fat 14%, and sodium 6%. CONCLUSION: Governments and policy makers should consider the adoption of traffic light labelling as a population level intervention to improve dietary intakes and chronic disease risk. PMID:28182630

Traffic-light labels could reduce population intakes of calories, total fat, saturated fat, and sodium.

PubMed

Emrich, Teri E; Qi, Ying; Lou, Wendy Y; L'Abbe, Mary R

2017-01-01

Traffic-light labelling has been proposed as a public health intervention to improve the dietary intakes of consumers. to model the potential impact of avoiding foods with red traffic lights on the label on the energy, total fat, saturated fat, sodium, and sugars intakes of Canadian adults. Canadian adults aged 19 and older (n = 19,915) who responded to the Canadian Community Health Survey (CCHS), Cycle 2.2. The nutrient levels in foods consumed by Canadians in CCHS were profiled using the United Kingdom's criteria for traffic light labelling. Whenever possible, foods assigned a red traffic light for one or more of the profiled nutrients were replaced with a similar food currently sold in Canada, with nutrient levels not assigned any red traffic lights. Average intakes of calories, total fat, saturated fat, sodium, and sugars under the traffic light scenario were compared with actual intakes of calories and these nutrients (baseline) reported in CCHS. Under the traffic light scenario, Canadian's intake of energy, total fat, saturated fat, and sodium were significantly reduced compared to baseline; sugars intakes were not significantly reduced. Calorie intake was reduced by 5%, total fat 13%, saturated fat 14%, and sodium 6%. Governments and policy makers should consider the adoption of traffic light labelling as a population level intervention to improve dietary intakes and chronic disease risk.

A fully-automated one-pot synthesis of [18F]fluoromethylcholine with reduced dimethylaminoethanol contamination via [18F]fluoromethyl tosylate.

PubMed

Rodnick, Melissa E; Brooks, Allen F; Hockley, Brian G; Henderson, Bradford D; Scott, Peter J H

2013-08-01

A novel one-pot method for preparing [(18)F]fluoromethylcholine ([(18)F]FCH) via in situ generation of [(18)F]fluoromethyl tosylate ([(18)F]FCH2OTs), and subsequent [(18)F]fluoromethylation of dimethylaminoethanol (DMAE), has been developed. [(18)F]FCH was prepared using a GE TRACERlab FXFN, although the method should be readily adaptable to any other fluorine-(18) synthesis module. Initially ditosylmethane was fluorinated to generate [(18)F]FCH2OTs. DMAE was then added and the reaction was heated at 120 °C for 10 min to generate [(18)F]FCH. After this time, reaction solvent was evaporated, and the crude reaction mixture was purified by solid-phase extraction using C(18)-Plus and CM-Light Sep-Pak cartridges to provide [(18)F]FCH formulated in USP saline. The formulated product was passed through a 0.22 µm filter into a sterile dose vial, and submitted for quality control testing. Total synthesis time was 1.25 h from end-of-bombardment. Typical non-decay-corrected yields of [(18)F]FCH prepared using this method were 91 mCi (7% non-decay corrected based upon ~1.3 Ci [(18)F]fluoride), and doses passed all other quality control (QC) tests. A one-pot liquid-phase synthesis of [(18)F]FCH has been developed. Doses contain extremely low levels of residual DMAE (31.6 µg/10 mL dose or ~3 ppm) and passed all other requisite QC testing, confirming their suitability for use in clinical imaging studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Fully-automated One-pot Synthesis of [18F]Fluoromethylcholine with Reduced Dimethylaminoethanol Contamination via [18F]Fluoromethyl Tosylate

PubMed Central

Rodnick, Melissa E.; Brooks, Allen F.; Hockley, Brian G.; Henderson, Bradford D.; Scott, Peter J. H.

2013-01-01

Introduction A novel one-pot method for preparing [18F]fluoromethylcholine ([18F]FCH) via in situ generation of [18F]fluoromethyl tosylate ([18F]FCH2OTs), and subsequent [18F]fluoromethylation of dimethylaminoethanol (DMAE), has been developed. Methods [18F]FCH was prepared using a GE TRACERlab FXFN, although the method should be readily adaptable to any other fluorine-18 synthesis module. Initially ditosylmethane was fluorinated to generate [18F]FCH2OTs. DMAE was then added and the reaction was heated at 120°C for 10 min to generate [18F]FCH. After this time, reaction solvent was evaporated, and the crude reaction mixture was purified by solid-phase extraction using C18-Plus and CM-Light Sep-Pak cartridges to provide [18F]FCH formulated in USP saline. The formulated product was passed through a 0.22 μm filter into a sterile dose vial, and submitted for quality control testing. Total synthesis time was 1.25 hours from end-of-bombardment. Results Typical non-decay-corrected yields of [18F]FCH prepared using this method were 91 mCi (7% non-decay corrected based upon ~1.3 Ci [18F]fluoride), and doses passed all other quality control (QC) tests. Conclusion A one-pot liquid-phase synthesis of [18F]FCH has been developed. Doses contain extremely low levels of residual DMAE (31.6 μg / 10 mL dose or ~3 ppm) and passed all other requisite QC testing, confirming their suitability for use in clinical imaging studies. PMID:23665261

Evaluation of the 2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide (HPPH) mediated photodynamic therapy by macroscopic singlet oxygen modeling.

PubMed

Penjweini, Rozhin; Kim, Michele M; Liu, Baochang; Zhu, Timothy C

2016-12-01

Photodynamic therapy (PDT) is known as a non-invasive treatment modality that is based on photochemical reactions between oxygen, photosensitizer, and a special wavelength of light. However, a dosimetric predictor for PDT outcome is still elusive because current dosimetric quantities do not account for the differences in the PDT oxygen consumption rate for different fluence rates. In this study, we evaluate several dose metrics, total fluence, photobleaching ratio, PDT dose, and mean reacted singlet oxygen (mean [ 1 O 2 ] rx ) for predicting the PDT outcome and a clinically relevant tumor re-growth endpoint. For this reason, radiation-induced fibrosarcoma (RIF) mice tumors are treated with 2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide (HPPH) and different in-air fluences (30 J/cm 2 , 50 J/cm 2 , 135 J/cm 2 , 250 J/cm 2 , and 350 J/cm 2 ) and in-air fluence rates (20, 50, 75, 150 mW/cm 2 ). Explicit measurements of HPPH and oxygen concentration as well as tissue optical properties are performed pre- and post-treatment. Then, this information is incorporated into a macroscopic model to calculate the photobleaching, PDT dose, and mean [ 1 O 2 ] rx . Changes in tumor volume are tracked following the treatment and compared with the dose metrics. The correlation demonstrates that mean [ 1 O 2 ] rx  serves as a better dosimetric quantity for predicting treatment outcome and a clinically relevant tumor re-growth endpoint. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sodium bicarbonate use and the risk of hypernatremia in thoracic aortic surgical patients with metabolic acidosis following deep hypothermic circulatory arrest

PubMed Central

Ghadimi, Kamrouz; Gutsche, Jacob T.; Ramakrishna, Harish; Setegne, Samuel L.; Jackson, Kirk R.; Augoustides, John G.; Ochroch, E. Andrew; Weiss, Stuart J.; Bavaria, Joseph E.; Cheung, Albert T.

2016-01-01

Objective: Metabolic acidosis after deep hypothermic circulatory arrest (DHCA) for thoracic aortic operations is commonly managed with sodium bicarbonate (NaHCO3). The purpose of this study was to determine the relationships between total NaHCO3 dose and the severity of metabolic acidosis, duration of mechanical ventilation, duration of vasoactive infusions, and Intensive Care Unit (ICU) or hospital length of stay (LOS). Methods: In a single center, retrospective study, 87 consecutive elective thoracic aortic operations utilizing DHCA, were studied. Linear regression analysis was used to test for the relationships between the total NaHCO3 dose administered through postoperative day 2, clinical variables, arterial blood gas values, and short-term clinical outcomes. Results: Seventy-five patients (86%) received NaHCO3. Total NaHCO3 dose averaged 136 ± 112 mEq (range: 0.0–535 mEq) per patient. Total NaHCO3 dose correlated with minimum pH (r = 0.41, P < 0.0001), minimum serum bicarbonate (r = −0.40, P < 0.001), maximum serum lactate (r = 0.46, P = 0.007), duration of metabolic acidosis (r = 0.33, P = 0.002), and maximum serum sodium concentrations (r = 0.29, P = 0.007). Postoperative hypernatremia was present in 67% of patients and peaked at 12 h following DHCA. Eight percent of patients had a serum sodium ≥ 150 mEq/L. Total NaHCO3 dose did not correlate with anion gap, serum chloride, not the duration of mechanical ventilator support, vasoactive infusions, ICU or hospital LOS. Conclusion: Routine administration of NaHCO3 was common for the management of metabolic acidosis after DHCA. Total dose of NaHCO3 was a function of the severity and duration of metabolic acidosis. NaHCO3 administration contributed to postoperative hypernatremia that was often severe. The total NaHCO3 dose administered was unrelated to short-term clinical outcomes. PMID:27397449

Dynamically accumulated dose and 4D accumulated dose for moving tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Heng; Li Yupeng; Zhang Xiaodong

2012-12-15

Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove themore » principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a 'pulsed beam'; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a 'continuous beam.' A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose difference between the dynamic dose and 4D dose as a function of number of deliveries and/or total deliver time was also established.« less

In vivo semiconductor dosimetry as part of routine quality assurance.

PubMed

Millwater, C J; MacLeod, A S; Thwaites, D I

1998-06-01

This paper describes the initial physics testing necessary before diodes can be used for in vivo dosimetry as well as the development of a protocol for clinical use in head and neck treatment and the preliminary results acquired. 50 patients were entered into the pilot study. A total of 300 treatment set-ups were measured (184 entrance doses and 116 exit doses). Wedged and unwedged components of each field were measured separately, making the total number of entrance doses 284 and total number of exit doses 207. There was no significant systematic deviation in the measured entrance dose compared with the expected (mean +0.4%, SD 2.7%). Discrepancies between the observed and expected entrance doses of greater than 5% were recorded in 6% (16/284) of measurements. The mean of the measured exit doses was 2.4% lower than expected (SD 4.8%). Discrepancies between the observed and expected exist doses of greater than 5% were recorded in 32% (67/207) of measurements. Possible causes for these discrepancies are discussed. Overall analysis of the data for individual patients suggest that in one patient out of the 50 there may have been a delivered target volume dose discrepancy of greater than 5% (+6.5%). The significance of the results and the implications for routine use are discussed.

Method for detecting radiation dose utilizing thermoluminescent material

DOEpatents

Miller, Steven D.; McDonald, Joseph C.; Eichner, Fred N.; Tomeraasen, Paul L.

1991-01-01

The amount of ionizing radiation to which a thermoluminescent material has been exposed is determined by first cooling the thermoluminescent material to a cryogenic temperature. The thermoluminescent material is then optically stimulated by exposure to ultraviolet light. Visible light emitted by the thermoluminescent material as it is allowed to warm up to room temperature is detected and counted. The thermoluminescent material may be annealed by exposure to ultraviolet light.

New Proof-of-Concept in Viral Inactivation: Virucidal Efficacy of 405 nm Light Against Feline Calicivirus as a Model for Norovirus Decontamination.

PubMed

Tomb, Rachael M; Maclean, Michelle; Coia, John E; Graham, Elizabeth; McDonald, Michael; Atreya, Chintamani D; MacGregor, Scott J; Anderson, John G

2017-06-01

The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log 10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm -2 . FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50-85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment.

The effect of noncoherent red light irradiation on proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells.

PubMed

Peng, Fei; Wu, Hua; Zheng, Yadong; Xu, Xiqiang; Yu, Jizhe

2012-05-01

Mesenchymal stem cells (MSCs) are promising for use in regenerative medicine. Low-level light irradiation (LLLI) has been shown to modulate various processes in different biological systems. The aim of our study was to investigate the effect of red light emitted from a light-emitting diode (LED) on bone marrow MSCs with or without osteogenic supplements. MSCs both with and without osteogenic supplements were divided into four groups, and each group was irradiated at doses of 0, 1, 2 and 4 J/cm(2). Cellular proliferation was evaluated using WST-8 and 5-ethynyl-2'-deoxyuridine (EdU) fluorescence staining. The alkaline phosphatase activity, mineralization, and expression of osteoblast master genes (Col1α1, Alpl, Bglap and Runx2) were monitored as indicators of MSC differentiation towards osteoblasts. In groups without osteogenic supplements, red light at all doses significantly stimulated cellular proliferation, whereas the osteogenic phenotype of the MSCs was not enhanced. In groups with osteogenic supplements, red light increased alkaline phosphatase activity and mineralized nodule formation, and stimulated the expression of Bglap and Runx2, but decreased cellular proliferation. In conclusion, nonconherent red light can promote proliferation but cannot induce osteogenic differentiation of MSCs in normal media, while it enhances osteogenic differentiation and decreases proliferation of MSCs in media with osteogenic supplements.

Assessment of dose rate to terrestrial biota in the area around coal fired power plant applying ERICA tool and RESRAD BIOTA code.

PubMed

Ćujić, Mirjana; Dragović, Snežana

2018-08-01

This paper presents the environmental radiation risk assessment based on two software program approaches ERICA Tool (version 1.2) and RESRAD BIOTA (version 1.5) to estimate dose rates to terrestrial biota in the area around the largest coal fired power plant in Serbia. For dose rate assessment software's default reference animals and plants and the best estimated values of activity concentrations of 238 U, 234 U, 234 Th, 232 Th, 230 Th, 226 Ra, 210 Pb, 210 Po, 137 Cs in soil were used. Both approaches revealed the highest contribution to the internal dose rate due to 226 Ra and 210 Po, while 137 Cs contributed the most to the external dose rate. In the investigated area total dose rate to biota derived using ERICA Tool ranged from 0.3 to 14.4 μGy h -1 . The natural radionuclides exhibited significantly higher contribution to the total dose rate than the artificial one. In the investigated area, only dose rate for lichens and bryophytes exceeded ERICA Tool screening value of total dose rate of 10 μGy h -1 suggested as confident that environmental risks are negligible. The assessed total dose rates for reference animals and plants using RESRAD BIOTA were found to be 7 and 3 μGy h -1 , respectively. In RESRAD BIOTA - Level 3, 10 species (Lumbricus terrestris, Rana lessonae, Sciurus vulgaris, Anas platyrhynchos, Lepus europaeus, Vulpes vulpes, Capreolus capreolus, Suss crofa, Quercu srobur, Tilia spp.) representative for the study area were modeled. Among them the highest total dose rate (4.5 μGy h -1 ) was obtained for large mammals. Differences in the predicted dose rates to biota using the two software programs are the consequence of the difference in the values of transfer parameters used to calculate activity concentrations in biota. Doses of ionizing radiation estimated in this study will not exhibit deterministic effects at the population level. Thus, the obtained results indicate no significant radiation impact of coal fired power plant operation on terrestrial biota. This paper confirms the use ERICA Tool and RESRAD BIOTA softwares as flexible and effective means of radiation impact assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Upgrade to iterative image reconstruction (IR) in abdominal MDCT imaging: a clinical study for detailed parameter optimization beyond vendor recommendations using the adaptive statistical iterative reconstruction environment (ASIR).

PubMed

Mueck, F G; Körner, M; Scherr, M K; Geyer, L L; Deak, Z; Linsenmaier, U; Reiser, M; Wirth, S

2012-03-01

To compare the image quality of dose-reduced 64-row abdominal CT reconstructed at different levels of adaptive statistical iterative reconstruction (ASIR) to full-dose baseline examinations reconstructed with filtered back-projection (FBP) in a clinical setting and upgrade situation. Abdominal baseline examinations (noise index NI = 29; LightSpeed VCT XT, GE) were intra-individually compared to follow-up studies on a CT with an ASIR option (NI = 43; Discovery HD750, GE), n = 42. Standard-kernel images were calculated with ASIR blendings of 0 - 100 % in slice and volume mode, respectively. Three experienced radiologists compared the image quality of these 567 sets to their corresponding full-dose baseline examination (- 2: diagnostically inferior, - 1: inferior, 0: equal, + 1: superior, + 2: diagnostically superior). Furthermore, a phantom was scanned. Statistical analysis used the Wilcoxon - the Mann-Whitney U-test and the intra-class correlation (ICC). The mean CTDIvol decreased from 19.7 ± 5.5 to 12.2 ± 4.7 mGy (p < 0.001). The ICC was 0.861. The total image quality of the dose-reduced ASIR studies was comparable to the baseline at ASIR 50 % in slice (p = 0.18) and ASIR 50 - 100 % in volume mode (p > 0.10). Volume mode performed 73 % slower than slice mode (p < 0.01). After the system upgrade, the vendor recommendation of ASIR 50 % in slice mode allowed for a dose reduction of 38 % in abdominal CT with comparable image quality and time expenditure. However, there is still further dose reduction potential for more complex reconstruction settings. © Georg Thieme Verlag KG Stuttgart · New York.

Recent Total Ionizing Dose and Displacement Damage Compendium of Candidate Electronics for NASA Space Systems

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; Boutte, Alvin J.; Campola, Michael J.; Carts, Martin A.; Casey, Megan C.; Chen, Dakai; LaBel, Kenneth A.; Ladbury, Raymond L.; Lauenstein, Jean-Marie; Marshall, Cheryl J.;

Comparison of PDR brachytherapy and external beam radiation therapy in the case of breast cancer

NASA Astrophysics Data System (ADS)

Teymournia, L.; Berger, D.; Kauer-Dorner, D.; Poljanc, K.; Seitz, W.; Aiginger, H.; Kirisits, C.

2009-04-01

Pulsed dose rate brachytherapy (PDR) was compared to external beam radiation therapy (EBRT) in the case of breast cancer. The benefits were figured out by evaluation of dosimetric parameters and calculating the normal tissue complication probability (NTCP). PDR plans were set up for five randomly chosen left-sided breast cancer patients delivering a total dose of 50.4 Gy to the target (dose rate 0.8 Gy h-1). For EBRT five left-sided breast cancer patients were planned using 3D-conformal tangential photon beams with a prescribed total dose of 50 Gy (2 Gy/fraction) to the total breast volume. For plan ranking and NTCP calculation the physical dose was first converted into the biologically effective dose (BED) and then into the normalized total dose (NTD) using the linear quadratic model with an α/β ratio of 3 Gy. In PDR the relative effectiveness (RE) was calculated for each dose bin of the differential dose volume histogram to get the BED. NTCPs were calculated for the ipsilateral lung and the heart as contoured on CT slices based on the Lyman model and the Kutcher reduction scheme. Dosimetric parameters as Vth (percentage of the total volume exceeding a threshold dose) and Jackson's fdam (fraction of the organ damaged) were also used to figure out the benefits. The comparison of calculated NTCPs in PDR and EBRT showed no difference between these two modalities. All values were below 0.01%. fdam derived from EBRT was always higher (mean value 8.95% versus 1.21% for the lung). The mean V10 and V20 of the lung related to BED were 6.32% and 1.72% for PDR versus 11.72% and 9.59% for EBRT. When using dosimetric parameters as Vth and fdam, PDR was mostly superior to EBRT in respect of sparing normal tissues. NTCP calculation as a single method of modality ranking showed a lack of information, especially when normal tissue was exposed to low radiation doses.

High-dose total-body irradiation and autologous marrow reconstitution in dogs: dose-rate-related acute toxicity and fractionation-dependent long-term survival

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deeg, H.J.; Storb, R.; Weiden, P.L.

1981-11-01

Beagle dogs treated by total-body irradiation (TBI) were given autologous marrow grafts in order to avoid death from marrow toxicity. Acute and delayed non-marrow toxicities of high single-dose (27 dogs) and fractionated TBI (20 dogs) delivered at 0.05 or 0.1 Gy/min were compared. Fractionated TBI was given in increments of 2 Gy every 6 hr for three increments per day. Acute toxicity and early mortality (<1 month) at identical total irradiation doses were comparable for dogs given fractionated or single-dose TBI. With single-dose TBI, 14, 16, and 18 Gy, respectively, given at 0.05 Gy/min, 0/5, 5/5, and 2/2 dogs diedmore » from acute toxicity; with 10, 12, and 14 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 5/5 dogs died acutely. With fractionated TBI, 14 and 16 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 2/2 dogs died auctely. Early deaths were due to radiation enteritis with or without associated septicemia (29 dogs; less than or equal to Day 10). Three dogs given 10 Gy of TBI at 0.1 Gy/min died from bacterial pneumonia; one (Day 18) had been given fractionated and two (Days 14, 22) single-dose TBI. Fifteen dogs survived beyond 1 month; eight of these had single-dose TBI (10-14 Gy) and all died within 7 months of irradiation from a syndrome consisting of hepatic damage, pancreatic fibrosis, malnutrition, wasting, and anemia. Seven of the 15 had fractionated TBI, and only one (14 Gy) died on Day 33 from hepatic failure, whereas 6 (10-14 Gy) are alive and well 250 to 500 days after irradiation. In conclusion, fractionated TBI did not offer advantages over single-dose TBI with regard to acute toxicity and early mortality; rather, these were dependent upon the total dose of TBI. The total acutely tolerated dose was dependent upon the exposure rate; however, only dogs given fractionated TBI became healthy long-term survivors.« less

Image gently, step lightly: increasing radiation dose awareness in pediatric interventions through an international social marketing campaign.

PubMed

Sidhu, Manrita K; Goske, Marilyn J; Coley, Brian J; Connolly, Bairbre; Racadio, John; Yoshizumi, Terry T; Utley, Tara; Strauss, Keith J

2009-09-01

In the past several decades, advances in imaging and interventional techniques have been accompanied by an increase in medical radiation dose to the public. Radiation exposure is even more important in children, who are more sensitive to radiation and have a longer lifespan during which effects may manifest. To address radiation safety in pediatric computed tomography, in 2008 the Alliance for Radiation Safety in Pediatric Imaging launched an international social marketing campaign entitled Image Gently. This article describes the next phase of the Image Gently campaign, entitled Step Lightly, which focuses on radiation safety in pediatric interventional radiology.

[Chlorophyll synthesis in cotyledons after gamma ray irradiation of black pine seeds].

PubMed

Bogdanović, M; Jelić, G

1992-01-01

The radiosensitivity of the greening system of Pinus nigra Arn. cotyledons has been studied in this paper. An exponential relation exists between the effect and dose for chlorophyll synthesis in the dark. Chlorophyll synthesis in the light roughly parallels that of chlorophyll synthesis in the dark. The restoration of chlorophyll was observed both in the light and in the dark. A stimulative effect of low doses of gamma radiation on chlorophyll synthesis was noticed. The radiosensitivity of chlorophyll a and chlorophyll b synthesis varied with the experimental conditions, suggesting that chlorophyll b synthesis might occur independently of chlorophyll a synthesis.

Optically-tracked handheld fluorescence imaging platform for monitoring skin response in the management of soft tissue sarcoma

NASA Astrophysics Data System (ADS)

Chamma, Emilie; Qiu, Jimmy; Lindvere-Teene, Liis; Blackmore, Kristina M.; Majeed, Safa; Weersink, Robert; Dickie, Colleen I.; Griffin, Anthony M.; Wunder, Jay S.; Ferguson, Peter C.; DaCosta, Ralph S.

2015-07-01

Standard clinical management of extremity soft tissue sarcomas includes surgery with radiation therapy. Wound complications (WCs) arising from treatment may occur due to bacterial infection and tissue breakdown. The ability to detect changes in these parameters during treatment may lead to earlier interventions that mitigate WCs. We describe the use of a new system composed of an autofluorescence imaging device and an optical three-dimensional tracking system to detect and coregister the presence of bacteria with radiation doses. The imaging device visualized erythema using white light and detected bacterial autofluorescence using 405-nm excitation light. Its position was tracked relative to the patient using IR reflective spheres and registration to the computed tomography coordinates. Image coregistration software was developed to spatially overlay radiation treatment plans and dose distributions on the white light and autofluorescence images of the surgical site. We describe the technology, its use in the operating room, and standard operating procedures, as well as demonstrate technical feasibility and safety intraoperatively. This new clinical tool may help identify patients at greater risk of developing WCs and investigate correlations between radiation dose, skin response, and changes in bacterial load as biomarkers associated with WCs.

Effects of a radiation dose reduction strategy for computed tomography in severely injured trauma patients in the emergency department: an observational study.

PubMed

Kim, Soo Hyun; Jung, Seung Eun; Oh, Sang Hoon; Park, Kyu Nam; Youn, Chun Song

2011-11-03

Severely injured trauma patients are exposed to clinically significant radiation doses from computed tomography (CT) imaging in the emergency department. Moreover, this radiation exposure is associated with an increased risk of cancer. The purpose of this study was to determine some effects of a radiation dose reduction strategy for CT in severely injured trauma patients in the emergency department. We implemented the radiation dose reduction strategy in May 2009. A prospective observational study design was used to collect data from patients who met the inclusion criteria during this one year study (intervention group) from May 2009 to April 2010. The prospective data were compared with data collected retrospectively for one year prior to the implementation of the radiation dose reduction strategy (control group). By comparison of the cumulative effective dose and the number of CT examinations in the two groups, we evaluated effects of a radiation dose reduction strategy. All the patients met the institutional adult trauma team activation criteria. The radiation doses calculated by the CT scanner were converted to effective doses by multiplication by a conversion coefficient. A total of 118 patients were included in this study. Among them, 33 were admitted before May 2009 (control group), and 85 were admitted after May 2009 (intervention group). There were no significant differences between the two groups regarding baseline characteristics, such as injury severity and mortality. Additionally, there was no difference between the two groups in the mean number of total CT examinations per patient (4.8 vs. 4.5, respectively; p = 0.227). However, the mean effective dose of the total CT examinations per patient significantly decreased from 78.71 mSv to 29.50 mSv (p < 0.001). The radiation dose reduction strategy for CT in severely injured trauma patients effectively decreased the cumulative effective dose of the total CT examinations in the emergency department. But not effectively decreased the number of CT examinations.

Mediation of acetylcholine and substance P induced contractions by myosin light chain phosphorylation in feline colonic smooth muscle.

PubMed

Washabau, Robert J; Holt, David E; Brockman, Daniel J

2002-05-01

To determine the role of myosin light chain phosphorylation in feline colonic smooth muscle contraction. Colonic tissue was obtained from eight 12- to 24-month-old cats. Colonic longitudinal smooth muscle strips were attached to isometric force transducers for measurements of isometric stress. Myosin light chain phosphorylation was determined by isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Stress and phosphorylation were determined following stimulation with ACh or SP, in the absence or presence of a calmodulin antagonist (W-7; 0.1 to 1.0 mM), myosin light chain kinase inhibitor (ML-9; 1 to 10 microM), or extracellular calcium free solutions. Unstimulated longitudinal colonic smooth muscle contained low amounts (6.9+/-3.2%) of phosphorylated myosin light chain. Phosphorylation of the myosin light chains was dose and time dependent with maximal values of 58.5% at 30 seconds of stimulation with 100 microM Ach and 60.2% at 45 seconds of stimulation with 100 nM SP Active isometric stress development closely paralleled phosphorylation of the myosin light chains in ACh- or SP-stimulated muscle. W-7 and ML-9 dose dependently inhibited myosin light chain phosphorylation and isometric stress development associated with ACh or SP stimulation. Removal of extracellular calcium inhibited myosin light chain phosphorylation and isometric stress development in ACh-stimulated smooth muscle. Feline longitudinal colonic smooth muscle contraction is calcium-, calmodulin-, and myosin light chain kinase-dependent. Myosin light chain phosphorylation is necessary for the initiation of contraction in feline longitudinal colonic smooth muscle. These findings may prove useful in determining the biochemical and molecular defects that accompany feline colonic motility disorders.

Homeopathic drug discovery: theory update and methodological aspect.

PubMed

Khuda-Bukhsh, Anisur Rahman; Pathak, Surajit

2008-08-01

Homeopathy treats patient on the basis of totality of symptoms and is based on the principle of 'like cures like'. It uses ultra-low doses of highly diluted natural substances as remedies that originate from plants, minerals or animals. The objectives of this review are to discuss concepts, controversies and research related to understanding homeopathy in the light of modern science. Attempts have been made to focus on current views of homeopathy and to delineate its most plausible mechanism(s) of action. Although some areas of concern remain, research carried out so far both in vitro and in vivo validates the effects of highly diluted homeopathic medicines in a wide variety of organisms. The precise mechanism(s) and pathway(s) of action of highly diluted homeopathic drugs are still unknown.

An evaluation of some pertinent parameters that influence the dosimetric performance of synthetic diamond detectors

NASA Astrophysics Data System (ADS)

Ade, N.; Nam, T. L.; Mhlanga, S. H.

2013-05-01

Although the near-tissue equivalence of diamond allows the direct measurement of dose for clinical applications without the need for energy-corrections, it is often cited that diamond detectors require pre-irradiation, a procedure necessary to stabilize the response or sensitivity of a diamond detector before dose measurements. In addition it has been pointed out that the relative dose measured with a diamond detector requires dose rate dependence correction and that the angular dependence of a detector could be due to its mechanical design or to the intrinsic angular sensitivity of the detection process. While the cause of instability of response has not been meticulously investigated, the issue of dose rate dependence correction is uncertain as some studies ignored it but reported good results. The aims of this study were therefore to investigate, in particular (1) the major cause of the unstable response of diamond detectors requiring pre-irradiation; (2) the influence of dose rate dependence correction in relative dose measurements; and (3) the angular dependence of the diamond detectors. The study was conducted with low-energy X-rays and electron therapy beams on HPHT and CVD synthesized diamonds. Ionization chambers were used for comparative measurements. Through systematic investigations, the major cause of the unstable response of diamond detectors requiring the recommended pre-irradiation step was isolated and attributed to the presence and effects of ambient light. The variation in detector's response between measurements in light and dark conditions could be as high as 63% for a CVD diamond. Dose rate dependence parameters (Δ values) of 0.950 and 1.035 were found for the HPHT and CVD diamond detectors, respectively. Without corrections based on dose rate dependence, the relative differences between depth-doses measured with the diamond detectors and a Markus chamber for exposures to 7 and 14 MeV electron beams were within 2.5%. A dose rate dependence correction using the Δ values obtained seemed to worsen the performance of the HPHT sample (up to about 3.3%) but it had a marginal effect on the performance of the CVD sample. In addition, the angular response of the CVD diamond detector was shown to be comparable with that of a cylindrical chamber. This study concludes that once the responses of the diamond detectors have been stabilised and they are properly shielded from ambient light, pre-irradiation prior to each measurement is not required. Also, the relative dose measured with the diamond detectors do not require dose rate dependence corrections as the required correction is only marginal and could have no dosimetric significance.

Current Status and Future Challenges in Risk-Based Radiation Engineering

NASA Technical Reports Server (NTRS)

Pellish, Jonathan A.

2017-01-01

This presentation covers the basis and challenges for radiation effects in electronic systems. The three main types of radiation effects in electronics are: 1) total ionizing dose (TID), 2) total non-ionizing dose (TNID) / displacement damage dose (DDD), and 3) single-event effect (SEE). Some content on relevant examples of effects, current concerns, and possible environmental model-driven solutions are also included.

Linac-based total body irradiation (TBI) with volumetric modulated arc therapy (VMAT)

NASA Astrophysics Data System (ADS)

Tas, B.; Durmus, I. F.; Okumus, A.; Uzel, O. E.

2017-02-01

To evaluate dose distribution of Volumetric modulated arc therapy (VMAT) planning tecnique using Versa HD® lineer accelerator to deliver Total Body Irradiation (TBI) on the coach. Eight TBI patient's Treatment Planning System (TPS) were performed with dual arc VMAT for each patient. The VMAT-TBI consisted of three isocentres and three dual overlapping arcs. The prescribed dose was 12 Gy. Mean dose to lung and kidney were restricted less than 10 Gy and max. dose to lens were restricted less than 6 Gy. The plans were verified using 2D array and ion chamber. The comparison between calculation and measurement were made by γ-index analysis and absolute dose. An average total delivery time was determined 923±34 seconds and an average MU was determined 2614±228 MUs for dual arc VMAT. Mean dose to lungs was 9.7±0.2 Gy, mean dose to kidneys was 8.8±0.3 Gy, max. dose to lens was 5.5±0.3 Gy and max. dose was 14.6±0.3 Gy, HI of PTV was 1.13±0.2, mean dose to PTV was 12.6±1.5 Gy and mean γ-index pass rate was %97.1±1.9. The results show that the tecnique for TBI using VMAT on the treatment coach is feasible.

Blue light induced reactive oxygen species from flavin mononucleotide and flavin adenine dinucleotide on lethality of HeLa cells.

PubMed

Yang, Ming-Yeh; Chang, Chih-Jui; Chen, Liang-Yü

2017-08-01

Photodynamic therapy (PDT) is a safe and non-invasive treatment for cancers and microbial infections. Various photosensitizers and light sources have been developed for clinical cancer therapies. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the cofactor of enzymes and are used as photosensitizers in this study. Targeting hypoxia and light-triggering reactive oxygen species (ROS) are experimental strategies for poisoning tumor cells in vitro. HeLa cells are committed to apoptosis when treated with FMN or FAD and exposed to visible blue light (the maximum emitted wavelength of blue light is 462nm). Under blue light irradiation at 3.744J/cm 2 (=0.52mW/cm 2 irradiated for 2h), the minimal lethal dose is 3.125μM and the median lethal doses (LD 50 ) for FMN and FAD are 6.5μM and 7.2μM, respectively. Individual exposure to visible blue light irradiation or riboflavin photosensitizers does not produce cytotoxicity and no side effects are observed in this study. The western blotting results also show that an intrinsic apoptosis pathway is activated by the ROS during photolysis of riboflavin analogues. Blue light triggers the cytotoxicity of riboflavins on HeLa cells in vitro. Based on these results, this is a feasible and efficient of PDT with an intrinsic photosensitizer for cancer research. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of genotoxic effect of taxol plus radiation on mice bone marrow cells.

PubMed

Ozkan, Lütfi; Egeli, Unal; Tunca, Berrin; Aydemir, Nilüfer; Ceçener, Gülşah; Akpinar, Gürler; Ergül, Emel; Cimen, Ciğdem; Ozuysal, Sema; Kahraman-Cetintaş, Sibel; Engin, Kayihan; Ahmed, Mansoor M

2002-01-01

In this study, we investigated the genotoxic effect of taxol, radiation, or taxol plus radiation on highly proliferative normal tissue-bone marrow cells of Swiss albino mice. Swiss-albino mice, 3-4 months old, were used in this study. Taxol was administered bolus intravenously through the tail vein. Radiation was given by using a linear accelerator. There were four treatment categories, which had a total of 34 groups. Each group consisted of five animals. The first was the control category that had one group (n = 5). The second treatment category was taxol alone, which had three groups as per taxol dose alone (n = 15). The third treatment category was radiation alone, which had three groups as per the radiation dose (n = 15). The fourth treatment category was taxol plus radiation, which had 27 groups as per combined radiation dose plus taxol dose concentration and as per pre-treatment timing sequence of taxol before radiation (n = 135). Mice were sacrificed 24 h after taxol or radiation or combined administration using ether anesthesia. The cells were then dropped on two labeled slides, flamed, air dried, and stained in 7% Giemsa; 20-30 well-spread mitotic metaphases were analyzed for each animal; the cells with chromosome breaks, acentric fragments, and rearrangements were evaluated on x1,000 magnification with light microscope (Zeiss axioplan). The mitotic index was determined by counting the number of mitotic cells among 1,000 cells per animal. Differences between groups were evaluated with Student's t-test statistically. Taxol caused a dose-dependent increase in chromosomal aberrations (P = 0.027). Similarly, radiation caused a dose-dependent increase in chromosomal aberrations (P = 0.003) and decreased mitotic index (P = 0.002). In combination, there were a small enhancements at the 40 mg/kg taxol dose level and at 0.25 and 0.5 Gy radiation doses in the 48 h group. However, an increase in chromosomal aberrations was observed after 48 hours of taxol exposure when compared 12 or 24 h of taxol exposure (P = 0.001 and P = 0.019). These findings suggest that taxol at the high doses with low dose radiation caused radiosensitizing effect in bone marrow cells. Forty-eight-hour pretreatment of taxol exposure followed by radiation caused significant induction of chromosomal aberrations and a reduction of mitotic index when compared to other taxol timing sequence. Copyright 2002 Wiley-Liss, Inc.

Depletion of florfenicol amine, marker residue of florfenicol, from the edible fillet of tilapia (Oreochromis niloticus x O. niloticus and O. niloticus x O. aureus) following florfenicol administration in feed

USGS Publications Warehouse

Gaikowski, M.P.; Mushtaq, M.; Cassidy, P.; Meinertz, J.R.; Schleis, S.M.; Sweeney, D.; Endris, R.G.

2010-01-01

Aquaflor??, a 50% feed premix containing the broad spectrum antibacterial agent florfenicol is available globally to control mortality associated with economically significant systemic bacterial diseases of fish. Florfenicol (FFC) is effective in controlling mortality associated with Streptococcus iniae in tilapia Oreochromis sp. when administered in medicated feed at a dose of 15 mg/kg bodyweight (BW)/d for 10 consecutive days. Our objective was to characterize the depletion of the FFC marker residue, florfenicol amine (FFA), from the edible tissue of market-weight Nile tilapia O. niloticus x O. niloticus and hybrid tilapia O. niloticus x O. aureus offered feed medicated with FFC at a nominal dose rate of 15 mg/kg BW/d for 12 days. Near market-weight tilapia were obtained from a commercial tilapia farm, distributed to 2 single pass (one for Nile tilapia and one for hybrid tilapia), flow-through systems and maintained at 27 ??C under a 15 h light:9 h dark photoperiod over a 41-d pre-dosing period. During the dosing period, tilapia were offered feed medicated with FFC at a concentration of 1.479 g/kg at 1% BW daily divided in three equal offerings. The initial 10-d dosing period was extended to 12 d because one tank did not consume > 75% of the feed offered during the first two dosing days. The total dose consumed by fish in each of the 2 tanks ranged from 147 to 167 mg/kg. Once during the pre-dose period and on days 1, 2, 4, 7, 14, 21, and 28 of the post-dose period, groups of fish were indiscriminately removed from each tank, measured for weight and length, scaled, filleted, and the skin-on fillets stored at <-70 ??C. Frozen fillets were individually homogenized, extracted, and FFA concentration was determined by high-performance liquid chromatography with UV detection. Florfenicol amine is rapidly eliminated from tilapia fillet after withdrawal from medication and depletion followed first-order kinetics with an estimated half-life of 2.32 d. The FFA tolerance limit, calculated as the 99th percentile of the potential residue level at 95% confidence, had depleted to less than the 1 ??g/g maximum residue level by 6.14 d after the dosing period.

Evaluation of light penetration on Navigation Pools 8 and 13 of the Upper Mississippi River

USGS Publications Warehouse

Giblin, Shawn; Hoff, Kraig; Fischer, Jim; Dukerschein, Terry

2010-01-01

The availability of light can have a dramatic affect on macrophyte and phytoplankton abundance in virtually all aquatic ecosystems. The Long Term Resource Monitoring Program and other monitoring programs often measure factors that affect light extinction (nonvolatile suspended solids, volatile suspended solids, and chlorophyll) and correlates of light extinction (turbidity and Secchi depth), but rarely do they directly measure light extinction. Data on light extinction, Secchi depth, transparency tube, turbidity, total suspended solids, and volatile suspended solids were collected during summer 2003 on Pools 8 and 13 of the Upper Mississippi River. Regressions were developed to predict light extinction based upon Secchi depth, transparency tube, turbidity, and total suspended solids. Transparency tube, Secchi depth, and turbidity all showed strong relations with light extinction and can effectively predict light extinction. Total suspended solids did not show as strong a relation to light extinction. Volatile suspended solids had a greater affect on light extinction than nonvolatile suspended solids. The data were compared to recommended criteria established for light extinction, Secchi depth, total suspended solids, and turbidity by the Upper Mississippi River Conservation Committee to sustain submersed aquatic vegetation in the Upper Mississippi River. During the study period, the average condition in Pool 8 met or exceeded all of the criteria whereas the average condition in Pool 13 failed to meet any of the criteria. This report provides river managers with an effective tool to predict light extinction based upon readily available data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farfan, E.; Jannik, T.

This article describes major studies performed by the Chernobyl Center's International Radioecology Laboratory (Slavutich, Ukraine) on radioecology of murine rodents and shrews inhabiting the Chernobyl Exclusion Zone. The article addresses the long-term (1986-2005) and seasonal dynamics of radioactive contamination of animals, and reviews interspecies differences in radionuclide accumulations and factors affecting the radionuclide accumulations. It is shown that bioavailability of radionuclides in the 'soil-to-plant' chain and a trophic specialization of animals play key roles in determining their actual contamination levels. The total absorbed dose rates in small mammals significantly reduced during the years following the Chernobyl Nuclear Power Plant accident.more » In 1986, the absorbed dose rate reached 1.3-6.0 Gy hr{sup -1} in the central areas of the Chernobyl Exclusion Zone (the 'Red Forest'). In 1988 and 1990, the total absorbed dose rates were 1.3 and 0.42 Gy hr{sup -1}, respectively. In 1995, 2000, and 2005, according to the present study, the total absorbed dose rates rarely exceeded 0.00023, 0.00018, and 0.00015 Gy hr{sup -1}, respectively. Contributions of individual radiation sources into the total absorbed dose are described.« less

SU-F-T-174: Patient-Specific Point Dose Measurement Using Fiber Optic Radiation Sensor Using Cerenkov Radiation for Proton Therapeutic Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Son, J; National Cancer Center, Goyang-si; Kim, M

Purpose: A fiber-optic radiation sensor using Cerenkov radiation (FOCR) has been widely studied for use as a dosimeter for proton therapeutic beam. We developed the FOCR, and it applied to patient-specific point dose measurement in order to evaluate the effectiveness of the FOCR system for proton therapy QA. Methods: Calibration of FOCR was performed with an ionization chamber whose absolute doses were determined according to the IAEA TRS-398 protocol. To determine the calibration curve, the FOCR was irradiated perpendicularly to the proton beam at the 13 dose levels steps. We selected five actual patient treatment plans performed at proton therapymore » center and compared the resulting FOCR measurements with the ionization chamber measurements. Results: The Cerenkov light yield of the FOCR increases linearly with as the dose measured using the ionization chamber increases from 0 cGy to 500 cGy. The results indicate that the fitting curve is linear, suggesting that dose measurement based on the light yield of the FOCR is possible. The results of proton radiation dose QA performed using the FOCR for 10 proton fields and five patients are good agreement with an ionization chamber. Conclusion: We carried out the patient QA using the FOCR for proton therapeutic beam and evaluated the effectiveness of the FOCR as a proton therapy QA tool. Our results indicate that the FOCR is suitable for use in patient QA of clinical proton beams.« less

Strategies for systemic radiotherapy of micrometastases using antibody-targeted 131I.

PubMed

Wheldon, T E; O'Donoghue, J A; Hilditch, T E; Barrett, A

1988-02-01

A simple analysis is developed to evaluate the likely effectiveness of treatment of micrometastases by antibody-targeted 131I. Account is taken of the low levels of tumour uptake of antibody-conjugated 131I presently achievable and of the "energy wastage" in targeting microscopic tumours with a radionuclide whose disintegration energy is widely dissipated. The analysis shows that only modest doses can be delivered to micrometastases when total body dose is restricted to levels which allow recovery of bone marrow. Much higher doses could be delivered to micrometastases when bone marrow rescue is used. A rationale is presented for targeted systemic radiotherapy used in combination with external beam total body irradiation (TBI) and bone marrow rescue. This has some practical advantages. The effect of the targeted component is to impose a biological non-uniformity on the total body dose distribution with regions of high tumour cell density receiving higher doses. Where targeting results in high doses to particular normal organs (e.g. liver, kidney) the total dose to these organs could be kept within tolerable limits by appropriate shielding of the external beam radiation component of the treatment. Greater levels of tumour cell kill should be achievable by the combination regime without any increase in normal tissue damage over that inflicted by conventional TBI. The predicted superiority of the combination regime is especially marked for tumours just below the threshold for detectability (e.g. approximately 1 mm-1 cm diameter). This approach has the advantage that targeted radiotherapy provides only a proportion of the total body dose, most of which is given by a familiar technique. The proportion of dose given by the targeted component could be increased as experience is gained. The predicted superiority of the combination strategy should be experimentally testable using laboratory animals. Clinical applications should be cautiously approached, with due regard to the limitations of the theoretical analysis.

Effects of gamma radiation on hard dental tissues of albino rats: investigation by light microscopy.

PubMed

El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; El-Zainy, Medhat

2013-08-01

The present work aims at studying the effect of gamma radiation on the hard dental tissues. Eighty adult male albino rats with weights of about 250 g were used. The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy whole-body gamma doses. The effects on hard dental tissue samples were investigated after 48 h in histological and ground sections using light microscopy. Areas of acid phosphatase activity were detected using tartrate-resistant acid phosphatase (TRAP) stains. Observation of histological sections revealed disturbance in predentin thickness and odontoblastic layer as the irradiation dose increased. In cementum, widened cementocytes lacunae were occasionally detected even with low irradiated doses. On the other hand, relatively homogenous enamel was detected with darkened areas in enamel surface at doses over than 0.5 Gy. TRAP-positive cells were detected on the surface of the dentin of irradiated groups as well as cementum surface. Minimal detectable changes were observed in ground sections.

The Hematopoietic Syndrome of the Acute Radiation Syndrome in Rhesus Macaques: A Systematic Review of the Lethal Dose Response Relationship.

PubMed

MacVittie, Thomas J; Farese, Ann M; Jackson, William

2015-11-01

Well characterized animal models that mimic the human response to potentially lethal doses of radiation are required to assess the efficacy of medical countermeasures under the criteria of the U.S. Food and Drug Administration "animal rule." Development of a model requires the determination of the radiation dose response relationship and time course of mortality and morbidity across the hematopoietic acute radiation syndrome. The nonhuman primate, rhesus macaque, is a relevant animal model that may be used to determine the efficacy of medical countermeasures to mitigate major signs of morbidity and mortality at selected lethal doses of total body irradiation. A systematic review of relevant studies that determined the dose response relationship for the hematopoietic acute radiation syndrome in the rhesus macaque relative to radiation quality, dose rate, and exposure uniformity has never been performed. The selection of data cohorts was made from the following sources: Ovid Medline (1957-present), PubMed (1954-present), AGRICOLA (1976-present), Web of Science (1954-present), and U.S. HHS REPORT (2002 to present). The following terms were used: Rhesus, total body-irradiation, total body x irradiation, TBI, irradiation, gamma radiation, hematopoiesis, LD50/60, Macaca mulatta, whole-body irradiation, nonhuman primate, NHP, monkey, primates, hematopoietic radiation syndrome, mortality, and nuclear radiation. The reference lists of all studies, published and unpublished, were reviewed for additional studies. The total number of hits across all search sites was 3,001. There were a number of referenced, unpublished, non-peer reviewed government reports that were unavailable for review. Fifteen studies, 11 primary (n = 863) and four secondary (n = 153) studies [n = 1,016 total nonhuman primates (NHP), rhesus Macaca mulatta] were evaluated to provide an informative and consistent review. The dose response relationships (DRRs) were determined for uniform or non-uniform total body irradiation (TBI) with 250 kVp or 2 MeV x radiation, Co gamma radiation and reactor- and nuclear weapon-derived mixed gamma: neutron-radiation, delivered at various dose rates from a total body, bilateral, rotational, or unilateral exposure aspect. The DRRs established by a probit analysis vs. linear dose relationship were characterized by two main parameters or dependent variables: a slope and LD50/30. Respective LD50/30 values for studies that used 250 kVp x radiation (five primary studies combined, n = 338), 2 MeV x radiation, Co gamma radiation, and steady-state reactor-derived mixed gamma:neutron radiation for total body uniform exposures were 521 rad [498, 542], 671 rad [632, 715], 644 rad [613, 678], and 385 rad [357, 413]. The respective slopes were steep and ranged from 0.738 to 1.316. The DRR, LD50/30 values and slopes were also determined for total body, non-uniform, unilateral, pulse-rate exposures of mixed gamma:neutron radiation derived at reactor and nuclear weapon detonations. The LD50/30 values were, respectively, 395 rad [337, 432] and 412 rad [359, 460]. Secondary data sets of limited studies that did not describe a DRR were used to support the mid-to-high lethal dose range for the H-ARS and the threshold dose range for the concurrent acute GI ARS. The available evidence provided a reliable and extensive database that characterized the DRR for the H-ARS in young rhesus macaques exposed to 250 kVp uniform total body x radiation without the benefit of medical management. A less substantial but consistent database demonstrated the DRR for total body exposure of differing radiation quality, dose rate and non-uniform exposure. The DRR for the H-ARS is characterized by steep slopes and relative LD50/30 values that reflect the radiation quality, exposure aspect, and dose rate over a range in time from 1954-2012.

Compendium of Current Total Ionizing Dose Results and Displacement Damage Results for Candidate Spacecraft Electronics for NASA

NASA Technical Reports Server (NTRS)

Cochran, Donna J.; O'Bryan, Martha V.; Buchner, Stephen P.; Poivey, Christian; Ladbury, Ray L.; LaBel, Kenneth A.

2007-01-01

Sensitivity of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage is studied. Devices tested include optoelectronics, digital, analog, linear bipolar devices, and hybrid devices.

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2011 CFR

2011-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2012 CFR

2012-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2014 CFR

2014-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2013 CFR

2013-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

40 CFR Appendix A to Part 197 - Calculation of Annual Committed Effective Dose Equivalent

Code of Federal Regulations, 2010 CFR

2010-07-01

... resulting from irradiation of the tissue or organ to the total risk when the whole body is irradiated... internal irradiation from incorporated radionuclides, the total absorbed dose will be spread out in time...

Effects of a higher dose of near-infrared light on clinical signs and neuroprotection in a monkey model of Parkinson's disease.

PubMed

Moro, Cécile; El Massri, Nabil; Darlot, Fannie; Torres, Napoleon; Chabrol, Claude; Agay, Diane; Auboiroux, Vincent; Johnstone, Daniel M; Stone, Jonathan; Mitrofanis, John; Benabid, Alim-Louis

2016-10-01

We have reported previously that intracranial application of near-infrared light (NIr) - when delivered at the lower doses of 25J and 35J - reduces clinical signs and offers neuroprotection in a subacute MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) monkey model of Parkinson's disease. In this study, we explored whether a higher NIr dose (125J) generated beneficial effects in the same MPTP monkey model (n=15). We implanted an NIr (670nm) optical fibre device within a midline region of the midbrain in macaque monkeys, close to the substantia nigra of both sides. MPTP injections (1.8-2.1mg/kg) were made over a five day period, during which time the NIr device was turned on and left on continuously throughout the ensuing three week survival period. Monkeys were evaluated clinically and their brains processed for immunohistochemistry and stereology. Our results showed that the higher NIr dose did not have any toxic impact on cells at the midbrain implant site. Further, this NIr dose resulted in a higher number of nigral tyrosine hydroxylase immunoreactive cells when compared to the MPTP group. However, the higher NIr dose monkeys showed little evidence for an increase in mean clinical score, number of nigral Nissl-stained cells and density of striatal tyrosine hydroxylase terminations. In summary, the higher NIr dose of 125J was not as beneficial to MPTP-treated monkeys as compared to the lower doses of 25J and 35J, boding well for strategies of NIr dose delivery and device energy consumption in a future clinical trial. Copyright © 2016 Elsevier B.V. All rights reserved.

Curing potential of experimental resin composites with systematically varying amount of bioactive glass: Degree of conversion, light transmittance and depth of cure.

PubMed

Par, Matej; Spanovic, Nika; Bjelovucic, Ruza; Skenderovic, Hrvoje; Gamulin, Ozren; Tarle, Zrinka

2018-06-17

The aim of this work was to investigate the curing potential of an experimental resin composite series with the systematically varying amount of bioactive glass 45S5 by evaluating the degree of conversion, light transmittance and depth of cure. Resin composites based on a Bis-GMA/TEGDMA resin with a total filler load of 70 wt% and a variable amount of bioactive glass (0-40 wt%) were prepared. The photoinitiator system was camphorquinone and ethyl-4-(dimethylamino) benzoate. The degree of conversion and light transmittance were measured by Raman spectroscopy and UV-vis spectroscopy, respectively. The depth of cure was evaluated according to the classical ISO 4049 test. The initial introduction of bioactive glass into the experimental series diminished the light transmittance while the further increase in the bioactive glass amount up to 40 wt% caused minor variations with no clear trend. The curing potential of the experimental composites was similar to or better than that of commercial resin composites. However, unsilanized bioactive glass fillers demonstrated the tendency to diminish both the maximum attainable conversion and the curing efficiency at depth. Experimental composite materials containing bioactive glass showed a clinically acceptable degree of conversion and depth of cure. The degree of conversion and depth of cure were diminished by bioactive glass fillers in a dose-dependent manner, although light transmittance was similar among all of the experimental composites containing 5-40 wt% of bioactive glass. Reduced curing potential caused by the bioactive glass has possible consequences on mechanical properties and biocompatibility. Copyright © 2018 Elsevier Ltd. All rights reserved.

Simultaneous integrated vs. sequential boost in VMAT radiotherapy of high-grade gliomas.

PubMed

Farzin, Mostafa; Molls, Michael; Astner, Sabrina; Rondak, Ina-Christine; Oechsner, Markus

2015-12-01

In 20 patients with high-grade gliomas, we compared two methods of planning for volumetric-modulated arc therapy (VMAT): simultaneous integrated boost (SIB) vs. sequential boost (SEB). The investigation focused on the analysis of dose distributions in the target volumes and the organs at risk (OARs). After contouring the target volumes [planning target volumes (PTVs) and boost volumes (BVs)] and OARs, SIB planning and SEB planning were performed. The SEB method consisted of two plans: in the first plan the PTV received 50 Gy in 25 fractions with a 2-Gy dose per fraction. In the second plan the BV received 10 Gy in 5 fractions with a dose per fraction of 2 Gy. The doses of both plans were summed up to show the total doses delivered. In the SIB method the PTV received 54 Gy in 30 fractions with a dose per fraction of 1.8 Gy, while the BV received 60 Gy in the same fraction number but with a dose per fraction of 2 Gy. All of the OARs showed higher doses (Dmax and Dmean) in the SEB method when compared with the SIB technique. The differences between the two methods were statistically significant in almost all of the OARs. Analysing the total doses of the target volumes we found dose distributions with similar homogeneities and comparable total doses. Our analysis shows that the SIB method offers advantages over the SEB method in terms of sparing OARs.

Light intensity alters the extent of arsenic toxicity in Helianthus annuus L. seedlings.

PubMed

Yadav, Geeta; Srivastava, Prabhat Kumar; Singh, Vijay Pratap; Prasad, Sheo Mohan

2014-06-01

The present study is aimed at assessing the extent of arsenic (As) toxicity under three different light intensities-optimum (400 μmole photon m(-2) s(-1)), sub-optimum (225 μmole photon m(-2) s(-1)), and low (75 μmole photon m(-2) s(-1))-exposed to Helianthus annuus L. var. DRSF-113 seedlings by examining various physiological and biochemical parameters. Irrespective of the light intensities under which H. annuus L. seedlings were grown, there was an As dose (low, i.e., 6 mg kg(-1) soil, As1; and high, i.e., 12 mg kg(-1) soil, As2)-dependent decrease in all the growth parameters, viz., fresh mass, shoot length, and root length. Optimum light-grown seedlings exhibited better growth performance than the sub-optimum and low light-grown seedlings; however, low light-grown plants had maximum root and shoot lengths. Accumulation of As in the plant tissues depended upon its concentration used, proximity of the plant tissue, and intensity of the light. Greater intensity of light allowed greater assimilation of photosynthates accompanied by more uptake of nutrients along with As from the medium. The levels of chlorophyll a, b, and carotenoids declined with increasing concentrations of As. Seedlings acquired maximum Chl a and b under optimum light which were more compatible to face As1 and As2 doses of As, also evident from the overall status of enzymatic (SOD, POD, CAT, and GST) and non-enzymatic antioxidant (Pro).

Considerations on the calibration of small thermoluminescent dosimeters used for measurement of beta particle absorbed doses in liquid environments.

PubMed

Demidecki, A J; Williams, L E; Wong, J Y; Wessels, B W; Yorke, E D; Strandh, M; Strand, S E

1993-01-01

An investigation has been carried out on the factors which affect the absolute calibration of thermoluminescent dosimeters (TLDs) used in beta particle absorbed dose evaluations. Four effects on light output (LO) were considered: decay of detector sensitivity with time, finite TLD volume, dose linearity, and energy dependence. Most important of these was the decay of LO with time in culture medium, muscle tissue, and gels. This permanent loss of sensitivity was as large as an order of magnitude over a 21-day interval for the nominally 20-microns-thick disc-shaped CaSO4(Dy) TLDs in gel. Associated leaching of the dosimeter crystals out of the Teflon matrix was observed using scanning electron microscopy. Large channels leading from the outside environment into the TLDs were identified using SEM images. A possibility of batch dependence of fading was indicated. The second most important effect was the apparent reduction of light output due to finite size and increased specific gravity of the dosimeter (volume effect). We estimated this term by calculations as 10% in standard "mini" rods for beta particles from 90Y, but nearly a factor of 3 for 131I beta particles in the same geometry. No significant nonlinearity of the log (light output) with log (absorbed dose) over the range 0.05-20.00 Gy was discovered. Energy dependence of the LO was found to be not detectable, within measurement errors, over the range of 0.60-6.0 MeV mean energy electrons. With careful understanding of these effects, calibration via gel phantom would appear to be an acceptable strategy for mini TLDs used in beta absorbed dose evaluations in media.(ABSTRACT TRUNCATED AT 250 WORDS)

Singlet oxygen explicit dosimetry to predict long-term local tumor control for BPD-mediated photodynamic therapy

NASA Astrophysics Data System (ADS)

Kim, Michele M.; Penjweini, Rozhin; Ong, Yi Hong; Zhu, Timothy C.

2017-02-01

Photodynamic therapy (PDT) is a well-established treatment modality for cancer and other malignant diseases; however, quantities such as light fluence, photosensitizer photobleaching rate, and PDT dose do not fully account for all of the dynamic interactions between the key components involved. In particular, fluence rate (Φ) effects are not accounted for, which has a large effect on the oxygen consumption rate. In this preclinical study, reacted singlet oxygen [1O2]rx was investigated as a dosimetric quantity for PDT outcome. The ability of [1O2]rx to predict the long-term local tumor control rate (LCR) for BPD-mediated PDT was examined. Mice bearing radioactivelyinduced fibrosarcoma (RIF) tumors were treated with different in-air fluences (250, 300, and 350 J/cm2) and in-air ϕ (75, 100, and150 mW/cm2) with a BPD dose of 1 mg/kg and a drug-light interval of 3 hours. Treatment was delivered with a collimated laser beam of 1 cm diameter at 690 nm. Explicit dosimetry of initial tissue oxygen concentration, tissue optical properties, and BPD concentration was used to calculate [1O2]rx. Φ was calculated for the treatment volume based on Monte-Carlo simulations and measured tissue optical properties. Kaplan-Meier analyses for LCR were done for an endpoint of tumor volume <= 100 mm3 using four dose metrics: light fluence, photosensitizer photobleaching rate, PDT dose, and [1O2]rx. PDT dose was defined as the product of the timeintegral of photosensitizer concentration and Φ at a 3 mm tumor depth. Preliminary studies show that [1O2]rx better correlates with LCR and is an effective dosimetric quantity that can predict treatment outcome.

Skin autofluorescence reflects individual seasonal UV exposure, skin photodamage and skin cancer development in organ transplant recipients.

PubMed

Togsverd-Bo, Katrine; Philipsen, Peter Alshede; Hædersdal, Merete; Wulf, Hans Christian Olsen

2018-01-01

Ultraviolet radiation (UVR)-induced skin cancers varies among organ transplant recipients (OTRs). To improve individual risk assessment of skin cancer, objectively quantified skin photodamage is needed. We measured personal UVR-exposure dose in OTRs and assessed the relation between individual UVR exposure, skin cancer and objectively measured photodamage in terms of skin autofluorescence, pigmentation, and black light-evaluated solar lentigines. Danish OTRs with (n=15) and without a history of skin cancer (n=15) kept sun diaries from May to September and wore personal dosimeters recording time-stamped UVR doses in standard erythema doses (SED). Photodamage was quantified as skin autofluorescence with excitation at 370nm (F370) and 430nm (F430), skin pigmentation (pigment protection factor, PPF), and black light-evaluated solar lentigines. OTRs with skin cancer received a higher UVR dose than OTRs without skin cancer (median 116 SED vs. 67 SED, p=0.07) and UVR exposure doses were correlated with increased PPF (p=0.052) and F370 on the shoulder (F370 shoulder ) (p=0.04). We found that skin cancer was associated with F370 shoulder (OR 10.53, CI 3.3-31,938; p=0.018) and time since transplantation (OR 1.34, CI 0.95-1.91, p=0.097). A cut-off at 7.2 arbitrary units, 89% of OTRs with skin cancer had F370 shoulder values above 7.2 arbitrary units and F370 shoulder was additionally related to patient age (p=0.09) and black light-evaluated solar lentigines (p=0.04). F370 autofluorescence indicates objectively measured photodamage and may be used for individual risk assessment of skin cancer development in OTRs. Copyright © 2017. Published by Elsevier B.V.

Does the lead apron and collar always reduce radiation dose?

PubMed

Nortje, C J; Harris, A M; Lackovic, K P; Wood, R E

2001-11-01

The possibility that personal lead shielding devices can increase absorption of radiation has not been entertained. The purpose of the present investigation specifically was to determine whether pituitary dose might be increased when a leaded apron and thyroid collar are used. Thermoluminescent dosimeters (TLDs) were used to measure absorbed dose. They were calibrated at the kVp used in the clinical situation and a calibration curve relating light output to dose was generated. Lithium fluoride TLD discs were placed in the pituitary gland region of a Rando-Alderson female human phantom. The equivalent of 100 transpharyngeal exposures were delivered. The resultant light output from recovered dosimeters was converted to a uGy value using the calibration curve. The experiment was repeated using a 0.25 mm lead equivalent collar and apron fitted to the phantom in the customary manner. The entire process was repeated in order to have 30 dosimeters for the unshielded and 30 dosimeters for the shielded conditions. A further 30 dosimeters were sham irradiated and served as controls. A statistical comparison between unshielded and shielded conditions was performed. When the leaded apron and thyroid collar were used the absorbed dose to the pituitary gland was increased significantly (P < 0.05). Following this a second group, using a different dosimetry system and a male phantom repeated the experiment. In both cases, the shielded phantom received significantly higher dose to the pituitary region than the unshielded.

Micron MT29F128G08AJAAA 128GB Asynchronous Flash Memory Total Ionizing Dose Characterization Test Report

NASA Technical Reports Server (NTRS)

Campola, Michael; Wyrwas, Edward

2017-01-01

The purpose of this test was to characterize the Micron MT29F128G08AJAAAs parameter degradation for total dose response and to evaluate and compare lot date codes for sensitivity. In the test, the device was exposed to both low dose and high dose rate (HDR) irradiations using gamma radiation. Device parameters such as leakage currents, quantity of upset bits and overall chip and die health were investigated to determine which lot is more robust.

Differences in botulinum toxin dosing between patients with adductor spasmodic dysphonia and essential voice tremor.

PubMed

Orbelo, Diana M; Duffy, Joseph R; Hughes Borst, Becky J; Ekbom, Dale; Maragos, Nicolas E

2014-01-01

To explore possible dose differences in average botulinum toxin (BTX) given to patients with adductor spasmodic dysphonia (ADSD) compared with patients with essential voice tremor (EVT). A retrospective study compared the average BTX dose injected in equal doses to the thyroarytenoid (TA) muscles of 51 patients with ADSD with 52 patients with EVT. Those with ADSD received significantly higher total doses (6.80 ± 2.79 units) compared with those with EVT (5.02 ± 1.65 units). Dose at time of first injection, age at time of first injection, gender, year of first injection, and average time between injections were included in multivariate analysis but did not interact with total average dose findings. Patients with ADSD may need relatively higher doses of BTX injections to bilateral TA muscles compared with patients with EVT. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

Light, sleep and circadian rhythms in older adults with Alzheimer's disease and related dementias

PubMed Central

Figueiro, Mariana G

2017-01-01

Alzheimer's disease and related dementias (ADRD) can cause sleep and behavioral problems that are problematic for ADRD patients and their family caregivers. Light therapy has shown promise as a nonpharmacological treatment, and preliminary studies demonstrate that timed light exposure can consolidate and improve nighttime sleep efficiency, increase daytime wakefulness and reduce evening agitation without the adverse effects of pharmacological solutions. Compliance with light treatment and the accurate measurement of light exposures during treatment, however, have presented barriers for the adoption of light therapy for ADRD. Recent research showing that the circadian system is maximally sensitive to short-wavelength light opens the way for the potential application of lower, more-targeted light intensities to maximize compliance and individualize light dose/timing in therapeutic settings. PMID:28534696

In vivo adenylate cyclase activity in ultraviolet- and gamma-irradiated Escherichia coli.

PubMed

Chatterjee, A; Bhattacharya, A K

1988-06-01

The incorporation of [14C]adenine into the cyclic AMP fraction by whole cells of Escherichia coli B/r was taken as a measure of the in vivo adenylate cyclase activity. This activity was significantly inhibited by irradiation of the cells either with 60Co gamma-rays or with UV light from a germicidal lamp, suggesting inhibition of cyclic AMP synthesis. The incubation of cells after irradiation with lower doses (50-100 Gy) of gamma-rays produced a significant increase of in vivo adenylate cyclase activity, whereas there was no significant change after higher doses (150 Gy and above). Dark incubation of cells after irradiation with UV light (54 J m-2) led to recovery of enzyme activity to the level measured in unirradiated cells. Thus it appears that the catabolite repression of L-arabinose isomerase induced by UV light, as well as gamma-irradiation, is due to reduced cyclic AMP synthesis in irradiated cells.

[BiOBr promoted the photocatalytic degradation of beta-cypermethrin under visible light].

PubMed

Peng, Yi-Zhu; Zhao, Xiao-Rong; Jia, Man-Ke; Zhou, Wei; Huang, Ying-Ping

2014-05-01

As a visible light photocatalyst, bismuth oxide bromide (BiOBr) was used to catalyze the degradation of beta-cypermethrin (beta-CP). The photocatalytic degradation of beta-CP was studied with gas chromatography. The effects of pH and catalyst dose on the photocatalytic degradation efficiency were discussed. The oxidization and mineralization of beta-CP were detected by chemical oxygen demand (COD) analyzer. The results showed that beta-CP could be effectively degraded under visible light irradiation using BiOBr as the catalyst. At given experimental conditions, the degradation rate of beta-CP reached 94. 68% after 10 h and the COD removal rate reached 67. 99% after 36 h. With the increase of catalyst dose and pH value, the degradation rate was improved. The photocatalytic oxidation species was determined by peroxidase method and terephthalic acid fluorescence method. These results suggested that the photocatalytic degradation process mainly referred to hydroxyl radical ( OH) mechanism.

Effects of illumination on human nocturnal serum melatonin levels and performance

NASA Technical Reports Server (NTRS)

Dollins, A. B.; Lynch, H. J.; Wurtman, R. J.; Deng, M. H.; Lieberman, H. R.

1993-01-01

In humans, exposure to bright light at night suppresses the normal nocturnal elevation in circulating melatonin. Oral administration of pharmacological doses of melatonin during the day, when melatonin levels are normally minimal, induces fatigue. To examine the relationship between illumination, human pineal function, and behavior, we monitored the overnight serum melatonin profiles and behavioral performance of 24 healthy male subjects. On each of three separate occasions subjects participated in 13.5 h (1630-0800 h) testing sessions. Each subject was assigned to an individually illuminated workstation that was maintained throughout the night at an illumination level of approximately 300, 1500, or 3000 lux. Melatonin levels were significantly diminished by light treatment, F(2, 36) = 12.77, p < 0.001, in a dose-dependent manner. Performance on vigilance, reaction time, and other tasks deteriorated throughout the night, consistent with known circadian variations in these parameters, but independent of ambient light intensity and circulating melatonin levels.

Estimation of the total effective dose from low-dose CT scans and radiopharmaceutical administrations delivered to patients undergoing SPECT/CT explorations.

PubMed

Montes, Carlos; Tamayo, Pilar; Hernandez, Jorge; Gomez-Caminero, Felipe; García, Sofia; Martín, Carlos; Rosero, Angela

2013-08-01

Hybrid imaging, such as SPECT/CT, is used in routine clinical practice, allowing coregistered images of the functional and structural information provided by the two imaging modalities. However, this multimodality imaging may mean that patients are exposed to a higher radiation dose than those receiving SPECT alone. The study aimed to determine the radiation exposure of patients who had undergone SPECT/CT examinations and to relate this to the Background Equivalent Radiation Time (BERT). 145 SPECT/CT studies were used to estimate the total effective dose to patients due to both radiopharmaceutical administrations and low-dose CT scans. The CT contribution was estimated by the Dose-Length Product method. Specific conversion coefficients were calculated for SPECT explorations. The radiation dose from low-dose CTs ranged between 0.6 mSv for head and neck CT and 2.6 mSv for whole body CT scan, representing a maximum of 1 year of background radiation exposure. These values represent a decrease of 80-85% with respect to the radiation dose from diagnostic CT. The radiation exposure from radiopharmaceutical administration varied from 2.1 mSv for stress myocardial perfusion SPECT to 26 mSv for gallium SPECT in patients with lymphoma. The BERT ranged from 1 to 11 years. The contribution of low-dose CT scans to the total radiation dose to patients undergoing SPECT/CT examinations is relatively low compared with the effective dose from radiopharmaceutical administration. When a CT scan is only acquired for anatomical localization and attenuation correction, low-dose CT scan is justified on the basis of its lower dose.

Water and tissue equivalence of a new PRESAGE{sup Registered-Sign} formulation for 3D proton beam dosimetry: A Monte Carlo study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorjiara, Tina; Kuncic, Zdenka; Doran, Simon

2012-11-15

Purpose: To evaluate the water and tissue equivalence of a new PRESAGE{sup Registered-Sign} 3D dosimeter for proton therapy. Methods: The GEANT4 software toolkit was used to calculate and compare total dose delivered by a proton beam with mean energy 62 MeV in a PRESAGE{sup Registered-Sign} dosimeter, water, and soft tissue. The dose delivered by primary protons and secondary particles was calculated. Depth-dose profiles and isodose contours of deposited energy were compared for the materials of interest. Results: The proton beam range was found to be Almost-Equal-To 27 mm for PRESAGE{sup Registered-Sign }, 29.9 mm for soft tissue, and 30.5 mmmore » for water. This can be attributed to the lower collisional stopping power of water compared to soft tissue and PRESAGE{sup Registered-Sign }. The difference between total dose delivered in PRESAGE{sup Registered-Sign} and total dose delivered in water or tissue is less than 2% across the entire water/tissue equivalent range of the proton beam. The largest difference between total dose in PRESAGE{sup Registered-Sign} and total dose in water is 1.4%, while for soft tissue it is 1.8%. In both cases, this occurs at the distal end of the beam. Nevertheless, the authors find that PRESAGE{sup Registered-Sign} dosimeter is overall more tissue-equivalent than water-equivalent before the Bragg peak. After the Bragg peak, the differences in the depth doses are found to be due to differences in primary proton energy deposition; PRESAGE{sup Registered-Sign} and soft tissue stop protons more rapidly than water. The dose delivered by secondary electrons in the PRESAGE{sup Registered-Sign} differs by less than 1% from that in soft tissue and water. The contribution of secondary particles to the total dose is less than 4% for electrons and Almost-Equal-To 1% for protons in all the materials of interest. Conclusions: These results demonstrate that the new PRESAGE{sup Registered-Sign} formula may be considered both a tissue- and water-equivalent 3D dosimeter for a 62 MeV proton beam. The results further suggest that tissue-equivalent thickness may provide better dosimetric and geometric accuracy than water-equivalent thickness for 3D dosimetry of this proton beam.« less

SU-G-JeP3-10: Update On a Real-Time Treatment Guidance System Using An IR Navigation System for Pleural PDT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, M; Penjweini, R; Zhu, T

Purpose: Photodynamic therapy (PDT) is used in conjunction with surgical debulking of tumorous tissue during treatment for pleural mesothelioma. One of the key components of effective PDT is uniform light distribution. Currently, light is monitored with 8 isotropic light detectors that are placed at specific locations inside the pleural cavity. A tracking system with real-time feedback software can be utilized to improve the uniformity of light in addition to the existing detectors. Methods: An infrared (IR) tracking camera is used to monitor the movement of the light source. The same system determines the pleural geometry of the treatment area. Softwaremore » upgrades allow visualization of the pleural cavity as a two-dimensional volume. The treatment delivery wand was upgraded for ease of light delivery while incorporating the IR system. Isotropic detector locations are also displayed. Data from the tracking system is used to calculate the light fluence rate delivered. This data is also compared with in vivo data collected via the isotropic detectors. Furthermore, treatment volume information will be used to form light dose volume histograms of the pleural cavity. Results: In a phantom study, the light distribution was improved by using real-time guidance compared to the distribution when using detectors without guidance. With the tracking system, 2D data can be collected regarding light fluence rather than just the 8 discrete locations inside the pleural cavity. Light fluence distribution on the entire cavity can be calculated at every time in the treatment. Conclusion: The IR camera has been used successfully during pleural PDT patient treatment to track the motion of the light source and provide real-time display of 2D light fluence. It is possible to use the feedback system to deliver a more uniform dose of light throughout the pleural cavity.« less

Development of a center for light ion therapy and accurate tumor diagnostics at karolinska institutet and hospital

NASA Astrophysics Data System (ADS)

Brahme, Anders; Lind, Bengt K.

2002-04-01

Radiation therapy is today in a state of very rapid development with new intensity modulated treatment techniques continuously being developed. This has made intensity modulated electron and photon beams almost as powerful as conventional uniform beam proton therapy. To be able to cure also the most advanced hypoxic and radiation resistant tumors of complex local spread, intensity modulated light ion beams are really the ultimate tool and only slightly more expensive than proton therapy. The aim of the new center for ion therapy and tumor diagnostics in Stockholm is to develop radiobiologically optimized 3-dimensional pencil beam scanning techniques. Beside the "classical" approaches using low ionization density hydrogen ions (protons, but also deuterons and tritium nuclei) and high ionization density carbon ions, two new approaches will be developed. In the first one lithium or beryllium ions, that induce the least detrimental biological effect to normal tissues for a given biological effect in a small volume of the tumor, will be key particles. In the second approach, referred patients will be given a high-dose high-precision "boost" treatment with carbon or oxygen ions during one week preceding the final treatment with conventional radiations in the referring hospital. The rationale behind these approaches is to reduce the high ionization density dose to the normal tissue stroma inside the tumor and to ensure a microscopically uniform dose delivery. The principal idea of the center is to closely integrate ion therapy into the clinical routine and research of a large radiotherapy department. The light ion therapy center will therefore be combined with advanced tumor diagnostics including MR and PET-CT imaging to facilitate efficient high-precision high-dose boost treatment of remitted patients. The possibility to do 3D tumor diagnostics and 3D dose delivery verification with the same PET camera will be the ultimate step in high quality adaptive radiation therapy where alterations in the delivered dose can be corrected by subsequent treatments

Evaluation of Low-Dose Ultraviolet Light C for Reduction of Select ESKAPE Pathogens in a Canine Skin and Muscle Model.

PubMed

Dujowich, Mauricio; Case, J Brad; Ellison, Gary; Wellehan, James F X

2016-08-01

This study aimed at comparing the ability of low-dose UVC, 0.05% chlorhexidine, and combined UVC with 0.05% chlorhexidine to reduce colony-forming units (CFUs) on select ESKAPE pathogens (Staphylococcus aureus, Klebsiella pneumoniae, and Enterococcus faecium) in a canine skin and muscle model. Surgical site infections (SSIs) result in increased morbidity and cost. UVC damages DNA, rendering bacteria nonviable and does not discriminate between drug-sensitive and multi-drug-resistant organisms. Specimens were inoculated with one of three pathogens. Samples were treated with a 254 nm UVC mercury lamp or a 270 nm UVC LED light at 0.015, 0.03, or 0.04 J/cm(2) doses; 0.05% and 2% chlorhexidine were used as positive controls. To evaluate synergism, 0.05% chlorhexidine was used with 0.015 J/cm(2) of UVC. CFUs were counted and compared against the negative control. There were no significant differences in CFU counts between samples of the same tissue type treated with different light sources of the same UVC dose. UVC significantly decreased CFUs when compared against all negative controls in both skin and muscle. There was no consistently superior bactericidal UVC dose identified for individual bacteria or for tissue type. The bactericidal activity of UVC at 0.015 J/cm(2) versus 0.05% chlorhexidine was not different in muscle for any bacteria. The bactericidal activity of UVC at 0.015 J/cm(2) was superior to 0.05% chlorhexidine in skin for S. aureus and K. pneumonia, but not E. faecium. Combination of UVC and 0.05% chlorhexidine showed synergy against E. faecium when evaluated on skin. Low-dose UVC shows promise as a rapid, effective, and synergistic means of reducing bacterial burdens, which may decrease the incidence of SSIs. It should be further evaluated for use when 2% chlorhexidine would be contraindicated or impractical, such as open wounds or surgical sites.

Exploring Radiotherapy Targeting Strategy and Dose: A Pooled Analysis of Cooperative Group Trials of Combined Modality Therapy for Stage III Non-Small Cell Lung Cancer.

PubMed

Schild, Steven E; Fan, Wen; Stinchcombe, Thomas E; Vokes, Everett E; Ramalingam, Suresh S; Bradley, Jeffrey D; Kelly, Karen; Pang, Herbert H; Wang, Xiaofei

2018-04-21

Concurrent chemoradiotherapy(CRT) is standard therapy for locally-advanced non-small-cell lung cancer(LA-NSCLC)patients. This study was performed to examine thoracic radiotherapy(TRT) parameters and their impact on patient survival. We collected Individual patient data(IPD) from 3600LA-NSCLC patients participating in 16 cooperative group trials of concurrent CRT. The primary TRT parameters examined included field design strategy(elective nodal irradiation(ENI) compared to involved field TRT(IF-TRT)), total dose, and biologically effective dose(BED). Hazard ratios(HRs) for overall survival were calculated with univariable and multivariable Cox models. TRT doses ranged from 60 to 74 Gy with most treatments administered once-daily. ENI was associated with poorer survival than IF-TRT(univariable HR,1.37;95%CI,1.24-1.51,p<0.0001;multivariable HR,1.31;95%CI,1.08-1.59,p=0.002). The median survival of the IF and ENI patients were 24 and 16 months, respectively. Patients were divided into 3 dose groups: low total dose(60 Gy), medium total dose(>60Gy-66Gy) and high total dose(>66Gy-74 Gy). With reference to the low dose group, the multivariable HR's were 1.08 for the medium dose group(95%CI=0.93-1.25) and 1.12 for the high dose group(CI=0.97-1.30).The univariate p=0.054 and multivariable p=0.17. BED was grouped as follows: low(<55.5Gy 10 ), medium(=55.5 Gy 10) , or high(>55.5 Gy 10 ). With reference to the low BED group, the HR was 1.00(95%CI=0.85-1.18) for the medium BED group and 1.10(95%CI=0.93-1.31) for the high BED group. The univariable p=0.076 and multivariable p=0.16. For LA-NSCLC patients treated with concurrent CRT, IF-TRT was associated with significantly better survival than ENI-TRT. TRT total and BED dose levels were not significantly associated with patient survival. Future progress will require research focusing on better systemic therapy and TRT. Copyright © 2018. Published by Elsevier Inc.

Phytochemical screening, acute toxicity, anxiolytic and antidepressant activities of the Nelumbo nucifera fruit.

PubMed

Rajput, Muhammad Ali; Khan, Rafeeq Alam

2017-06-01

Recently use of herbal therapies and diet rich in flavonoids and vitamin C have increased significantly to treat minor to modest anxiety disorders and various forms of depression. But further research and studies are necessary to evaluate the pharmacological & toxicological effects of plants. Hence present study was designed to conduct phytochemical screening, acute toxicity study, anxiolytic and antidepressant activities of the ethanol extract of Nelumbo nucifera fruit in order to ascertain its therapeutic potential. The qualitative phytochemical screening of the seed pods of the N. nucifera fruit extract exposed the existence of flavonoids, saponins, alkaloids, tannins and terpenoids in it. The acute toxicity of the N. nucifera fruit extract in mice revealed its LD 50 value to be greater than 5000 mg/kg. Antianxiety activity was determined by elevated plus maze and light and dark test using 35 male Wister rats weighing 200-220 g which were equally divided in to 5 groups. The animals used in EPM underwent testing in light and dark box just 30 min after EPM. The antidepressant effect was assessed by forced swimming test using 35 male albino mice weighing 20-25 g equally divided in to 5 groups. In elevated plus maze, N. nucifera fruit extract exhibited substantial rise in number of open arm entries and time spent in open arms at dose 50 mg/kg while highly noteworthy increase in both parameters were observed at extract doses 100 and 200 mg/kg as compared to control. In light dark test highly significant increase in the percentage of time spent in light compartment was observed as compared to control. In forced swimming test highly noteworthy decline in duration of immobility was recorded at doses 100 and 200 mg/kg on 15th day i-e after administration of 14 doses, as compared to control; whereas same doses demonstrated significant decrease as compared to control in duration of immobility after single dose administration i-e on 2nd day of experiment. Thus N. nucifera fruit have exhibited strong anxiolytic and antidepressant effects and proved to have a great potential for therapeutic applications such as anxiety and depression and thus encourage more preclinical and clinical trials in this field.

Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

NASA Astrophysics Data System (ADS)

Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

2016-04-01

Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

Singlet oxygen explicit dosimetry to predict local tumor control for HPPH-mediated photodynamic therapy

NASA Astrophysics Data System (ADS)

Penjweini, Rozhin; Kim, Michele M.; Ong, Yi Hong; Zhu, Timothy C.

2017-02-01

This preclinical study examines four dosimetric quantities (light fluence, photosensitizer photobleaching ratio, PDT dose, and reacted singlet oxygen ([1O2]rx)) to predict local control rate (LCR) for 2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide (HPPH)-mediated photodynamic therapy (PDT). Mice bearing radiation-induced fibrosarcoma (RIF) tumors were treated with different in-air fluences (135, 250 and 350 J/cm2) and in-air fluence rates (50, 75 and 150 mW/cm2) at 0.25 mg/kg HPPH and a drug-light interval of 24 hours using a 1 cm diameter collimated laser beam at 665 nm wavelength. A macroscopic model was used to calculate ([1O2]rx)) based on in vivo explicit dosimetry of the initial tissue oxygenation, photosensitizer concentration, and tissue optical properties. PDT dose was defined as a temporal integral of drug concentration and fluence rate (φ) at a 3 mm tumor depth. Light fluence rate was calculated throughout the treatment volume based on Monte-Carlo simulation and measured tissue optical properties. The tumor volume of each mouse was tracked for 30 days after PDT and Kaplan-Meier analyses for LCR were performed based on a tumor volume <=100 mm3, for four dose metrics: fluence, HPPH photobleaching rate, PDT dose, and ([1O2]rx)). The results of this study showed that ([1O2]rx)) is the best dosimetric quantity that can predict tumor response and correlate with LCR.

Chemical modification of normal tissue damage induced by photodynamic therapy.

PubMed Central

Sigdestad, C. P.; Fingar, V. H.; Wieman, T. J.; Lindberg, R. D.

1996-01-01

One of the limitations of successful use of photodynamic therapy (PDT) employing porphyrins is the acute and long-term cutaneous photosensitivity. This paper describes results of experiments designed to test the effects of two radiation protective agents (WR-2721, 500 mg kg-1 or WR-3689, 700 mg kg-1) on murine skin damage induced by PDT. C3H mice were shaved and depilated three days prior to injection with the photosensitiser, Photofrin (5 or 10 mg kg-1). Twenty-four hours later, the mice were injected intraperitoneally with a protector 30 min prior to Argon dye laser (630 nm) exposure. The skin response was followed for two weeks post irradiation using an arbitrary response scale. A light dose response as well as a drug dose response was obtained. The results indicate that both protectors reduced the skin response to PDT, however WR-2721 was demonstrated to be the most effective. The effect of the protectors on vascular stasis after PDT was determined using a fluorescein dye exclusion assay. In mice treated with Photofrin (5 mg kg-1), and 630 nm light (180 J cm-2) pretreatment with either WR-2721 or WR-3689 resulted in significant protection of the vascular effects of PDT. These studies document the ability of the phosphorothioate class of radiation protective agents to reduce the effects of light on photosensitized skin. They do so in a drug dose-dependent fashion with maximum protection at the highest drug doses. PMID:8763855

Total-dose radiation effects data for semiconductor devices, volume 2

NASA Technical Reports Server (NTRS)

Price, W. E.; Martin, K. E.; Nichols, D. K.; Gauthier, M. K.; Brown, S. F.

1981-01-01

Total ionizing dose radiation test data on integrated circuits are analyzed. Tests were performed with the electron accelerator (Dynamitron) that provides a steady state 2.5 MeV electron beam. Some radiation exposures were made with a Cobalt-60 gamma ray source. The results obtained with the Cobalt-60 source are considered an approximate measure of the radiation damage that would be incurred by an equivalent dose of electrons.

Comparative analysis of dosimetry parameters for nuclear medicine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toohey, R.E.; Stabin, M.G.

For years many have employed the concept of ``total-body dose`` or ``whole-body dose,`` i.e., the total energy deposited in the body divided by the mass of the body, when evaluating the risks of different nuclear medicine procedures. The effective dose equivalent (H{sub E}), first described in ICRP Publication 26, has been accepted by some as a better quantity to use in evaluating the total risk of a procedure, but its use has been criticized by others primarily because the tissue weighting factors were intended for use in the radiation worker, rather than the nuclear medicine patient population. Nevertheless, in ICRPmore » Publication 52, the ICRP has suggested that the H{sub E} may be used in nuclear medicine. The ICRP also has published a compendium of dose estimates, including H{sub E} values, for various nuclear medicine procedures at various ages in ICRP Publication 53. The effective dose (E) of ICRP Publication 60 is perhaps more suitable for use in nuclear medicine, with tissue weighting factors based on the entire population. Other comparisons of H{sub E} and E have been published. The authors have used the program MIRDOSE 3.1 to compute total-body dose, H{sub E}, and E for 62 radiopharmaceutical procedures, based on the best current biokinetic data available.« less

Continuous background light significantly increases flashing-light enhancement of photosynthesis and growth of microalgae.

PubMed

Abu-Ghosh, Said; Fixler, Dror; Dubinsky, Zvy; Iluz, David

2015-01-01

Under specific conditions, flashing light enhances the photosynthesis rate in comparison to continuous illumination. Here we show that a combination of flashing light and continuous background light with the same integrated photon dose as continuous or flashing light alone can be used to significantly enhance photosynthesis and increase microalgae growth. To test this hypothesis, the green microalga Dunaliella salina was exposed to three different light regimes: continuous light, flashing light, and concomitant application of both. Algal growth was compared under three different integrated light quantities; low, intermediate, and moderately high. Under the combined light regime, there was a substantial increase in all algal growth parameters, with an enhanced photosynthesis rate, within 3days. Our strategy demonstrates a hitherto undescribed significant increase in photosynthesis and algal growth rates, which is beyond the increase by flashing light alone. Copyright © 2015 Elsevier Ltd. All rights reserved.

Improved Optics For Quasi-Elastic Light Scattering

NASA Technical Reports Server (NTRS)

Cheung, Harry Michael

1995-01-01

Improved optical train devised for use in light-scattering measurements of quasi-elastic light scattering (QELS) and laser spectroscopy. Measurements performed on solutions, microemulsions, micellular solutions, and colloidal dispersions. Simultaneous measurements of total intensity and fluctuations in total intensity of light scattered from sample at various angles provides data used, in conjunction with diffusion coefficients, to compute sizes of particles in sample.

[The "light" water effect on lenticular opacity development in mice after repeated low dose gamma-irradiation].

PubMed

Abrosimova, A N; Rakov, D V; Siniak, Iu E

2009-01-01

Action of "light" water with reduced quantities of heavy stable hydrogen and 18O ions on incidence and progress of lenticular opacity was studied in gamma-irradiated mice (60Co, 1.0 Gy). The animals were subjected to electroophthalmoscopy regularly till end of life time. The observation showed that chronic intake of "light" water safeguarded the irradiated mice against lenticular opacity. The experimental data indicate that "light" water strengthens the general body resistance as well as slows down aging of mammals.

Relationship between high daily erythemal UV doses, total ozone, surface albedo and cloudiness: An analysis of 30 years of data from Switzerland and Austria

NASA Astrophysics Data System (ADS)

Rieder, H. E.; Staehelin, J.; Weihs, P.; Vuilleumier, L.; Maeder, J. A.; Holawe, F.; Blumthaler, M.; Lindfors, A.; Peter, T.; Simic, S.; Spichtinger, P.; Wagner, J. E.; Walker, D.; Ribatet, M.

2010-10-01

This work investigates the occurrence frequency of days with high erythemal UV doses at three stations in Switzerland and Austria (Davos, Hoher Sonnblick and Vienna) for the time period 1974-2003. While several earlier studies have reported on increases in erythemal UV dose up to 10% during the last decades, this study focuses on days with high erythemal UV dose, which is defined as a daily dose at least 15% higher than for 1950s clear-sky conditions (which represent preindustrial conditions with respect to anthropogenic chlorine). Furthermore, the influence of low column ozone, clear-sky/partly cloudy conditions and surface albedo on UV irradiance has been analyzed on annual and seasonal basis. The results of this study show that in the Central Alpine Region the number of days with high UV dose increased strongly in the early 1990s. A large fraction of all days with high UV dose occurring in the period 1974-2003 was found especially during the years 1994-2003, namely 40% at Davos, 54% at Hoher Sonnblick and 65% at Vienna. The importance of total ozone, clear-sky/partly cloudy conditions and surface albedo (e.g. in dependence of snow cover) varies strongly among the seasons. However, overall the interplay of low total ozone and clear-sky/partly cloudy conditions led to the largest fraction of days showing high erythemal UV dose. Furthermore, an analysis of the synoptic weather situation showed that days with high erythemal UV dose, low total ozone and high relative sunshine duration occur at all three stations more frequently during situations with low pressure gradients or southerly advection.

Diagnostic radiation exposure in pediatric trauma patients.

PubMed

Brunetti, Marissa A; Mahesh, Mahadevappa; Nabaweesi, Rosemary; Locke, Paul; Ziegfeld, Susan; Brown, Robert

2011-02-01

The amount of imaging studies performed for disease diagnosis has been rapidly increasing. We examined the amount of radiation exposure that pediatric trauma patients receive because they are an at-risk population. Our hypothesis was that pediatric trauma patients are exposed to high levels of radiation during a single hospital visit. Retrospective review of children who presented to Johns Hopkins Pediatric Trauma Center from July 1, 2004, to June 30, 2005. Radiographic studies were recorded for each patient and doses were calculated to give a total effective dose of radiation. All radiographic studies that each child received during evaluation, including any associated hospital admission, were included. A total of 945 children were evaluated during the study year. A total of 719 children were included in the analysis. Mean age was 7.8 (±4.6) years. Four thousand six hundred three radiographic studies were performed; 1,457 were computed tomography (CT) studies (31.7%). Average radiation dose was 12.8 (±12) mSv. We found that while CT accounted for only 31.7% of the radiologic studies performed, it accounted for 91% of the total radiation dose. Mean dose for admitted children was 17.9 (±13.8) mSv. Mean dose for discharged children was 8.4 (±7.8) mSv (p<0.0001). Burn injuries had the lowest radiation dose [1.2 (±2.6) mSv], whereas motor vehicle collision victims had the highest dose [18.8 (±14.7) mSv]. When the use of radiologic imaging is considered essential, cumulative radiation exposure can be high. In young children with relatively long life spans, the benefit of each imaging study and the cumulative radiation dose should be weighed against the long-term risks of increased exposure.

Radiation optic neuropathy after megavoltage external-beam irradiation: Analysis of time-dose factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons, J.T.; Bova, F.J.; Million, R.R.

1994-11-15

To investigate the risk of radiation-induced optic neuropathy according to total radiotherapy dose and fraction size, based on both retrospective and prospectively collected data. Between October 1964 and May 1989, 215 optic nerves in 131 patients received fractionated external-beam irradiation during the treatment of primary extracranial head and neck tumors. All patients had a minimum of 3 years of ophthalmologic follow-up (range, 3 to 21 years). The clinical end point was visual acuity of 20/100 or worse as a result of optic nerve injury. Anterior ischemic optic neuropathy developed in five nerves (at mean and median times of 32 andmore » 30 months, respectively, and a range of 2-4 years). Retrobulbar optic neuropathy developed in 12 nerves (at mean and median times of 47 and 28 months, respectively, and a range of 1-14 years). No injuries were observed in 106 optic nerves that received a total dose of <59 Gy. Among nerves that received doses of {ge} 60 Gy, the dose per fraction was more important than the total dose in producing optic neuropathy. The 15-year actuarial risk of optic compared with 47% when given in fraction sizes {ge}1.9 Gy. The data also suggest an increased risk of optic nerve injury with increasing age. As there is no effective treatment of radiation-induced optic neuropathy, efforts should be directed at its prevention by minimizing the total dose, paying attention to the dose per fraction to the nerve, and using reduced field techniques where appropriate to limit the volume of tissues that receive high-dose irradiation. 32 refs., 5 figs., 5 tabs.« less

Light enhanced the accumulation of total fatty acids (TFA) and docosahexaenoic acid (DHA) in a newly isolated heterotrophic microalga Crypthecodinium sp. SUN.

PubMed

Sun, Dongzhe; Zhang, Zhao; Mao, Xuemei; Wu, Tao; Jiang, Yue; Liu, Jin; Chen, Feng

2017-03-01

In the present study, light illumination was found to be efficient in elevating the total fatty acid content in a newly isolated heterotrophic microalga, Crypthecodinium sp. SUN. Under light illumination, the highest total fatty acid and DHA contents were achieved at 96h as 24.9% of dry weight and 82.8mgg -1 dry weight, respectively, which were equivalent to 1.46-fold and 1.68-fold of those under the dark conditions. The elevation of total fatty acid content was mainly contributed by an increase of neutral lipids at the expense of starches. Moreover, light was found to alter the cell metabolism and led to a higher specific growth rate, higher glucose consumption rate and lower non-motile cell percentage. This is the first report that light can promote the total fatty acids accumulation in Crypthecodinium without growth inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mold and aflatoxin reduction by gamma radiation of packed hot peppers and their evolution during storage.

PubMed

Iqbal, Qumer; Amjad, Muhammad; Asi, Muhammad Rafique; Ariño, Agustin

2012-08-01

The effect of gamma radiation on moisture content, total mold counts, Aspergillus counts, and aflatoxins of three hot pepper hybrids (Sky Red, Maha, and Wonder King) was investigated. Whole dried peppers packed in polyethylene bags were gamma irradiated at 0 (control), 2, 4, and 6 kGy and stored at 25°C for 90 days. Gamma radiation proved to be effective in reducing total mold and Aspergillus counts in a dose-dependent relationship. Total mold counts in irradiated peppers immediately after treatments were significantly lowered compared with those in nonirradiated samples, achieving 90 and 99% reduction at 2- and 4-kGy doses, respectively. Aspergillus counts were significantly reduced, by 93 and 97%, immediately after irradiation at doses of 2 and 4 kGy, respectively. A radiation dose of 6 kGy completely eliminated the population of total molds and Aspergillus fungi. The evolution of total molds in control and irradiated samples indicated no further fungal proliferation during 3 months of storage at 25°C. Aflatoxin levels were slightly affected by radiation doses of 2 and 4 kGy and showed a nonsignificant reduction of 6% at the highest radiation dose of 6 kGy. The distinct effectiveness of gamma radiation in molds and aflatoxins can be explained by the target theory of food irradiation, which states that the likelihood of a microorganism or a molecule being inactivated by gamma rays increases as its size increases.

Evaluation of a fiber-optic fluorescence spectroscopy system to assist neurosurgical tumor resections

NASA Astrophysics Data System (ADS)

Ilias, Michail A.; Richter, Johan; Westermark, Frida; Brantmark, Martin; Andersson-Engels, Stefan; Wårdell, Karin

2007-07-01

The highly malignant brain tumor, glioblastoma multiforme, is difficult to totally resect without aid due to its infiltrative way of growing and its morphological similarities to surrounding functioning brain under direct vision in the operating field. The need for an inexpensive and robust real-time visualizing system for resection guiding in neurosurgery has been formulated by research groups all over the world. The main goal is to develop a system that helps the neurosurgeon to make decisions during the surgical procedure. A compact fiber optic system using fluorescence spectroscopy has been developed for guiding neurosurgical resections. The system is based on a high power light emitting diode at 395 nm and a spectrometer. A fiber bundle arrangement is used to guide the excitation light and fluorescence light between the instrument and the tissue target. The system is controlled through a computer interface and software package especially developed for the application. This robust and simple instrument has been evaluated in vivo both on healthy skin but also during a neurosurgical resection procedure. Before surgery the patient received orally a low dose of 5-aminolevulinic acid, converted to the fluorescence tumor marker protoporphyrin IX in the malignant cells. Preliminary results indicate that PpIX fluorescence and brain tissue autofluorescence can be recorded with the help of the developed system intraoperatively during resection of glioblastoma multiforme.

Rumen modulatory effect of thyme, clove and peppermint oils in vitro using buffalo rumen liquor.

PubMed

Roy, Debashis; Tomar, S K; Kumar, Vinod

2015-02-01

The present study was conducted to examine the rumen modulatory effect of thyme, clove and peppermint oils on rumen fermentation pattern in vitro using roughage based diet. Thyme, clove and peppermint oils were tested at concentration of 0, 30, 300 and 600 mg/l (ppm) of total culture fluid using in vitro gas production technique in wheat straw based diet (concentrate: Wheat straw 50:50). Different in vitro parameters e.g., total gas production, methane production, nutrient degradability, volatile fatty acid (VFA) production and ammonia nitrogen concentration were studied using buffalo rumen liquor. Thyme oil at higher dose level (600 ppm) reduced (p<0.05) total gas production, feed degradability and ammonia nitrogen (NH3-N) concentration whereas total VFA concentration was significantly lower (p>0.05) in 300 and 600 ppm dose levels. 600 ppm dose level of clove oil reduced (p<0.05) total gas production, feed degradability, total VFA and acetate to propionate ratio. Methane production was significantly reduced (p<0.05) in 300 and 600 ppm dose levels of clove and peppermint oil. Right combination of these essential oils may prove to enhance performance of animals by reducing methane production and inhibiting protein degradation in rumen.

SU-E-T-812: Volumetric Modulated Arc Therapy-Total Body Irradiation (VMAT-TBI) V.s. Conventional Extended SSD-TBI (cTBI): A Dosimetric Comparisom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouyang, L; Folkerts, M; Lee, H

2015-06-15

Purpose: To perform a dosimetric evaluation on a new developed volumetric modulated arc therapy based total body irradiation (VMAT-TBI). Methods: Three patients were CT scanned with an indexed rotatable body frame to get whole body CT images. Concatenated CT images were imported in Pinnacle treatment planning system and whole body and lung were contoured as PTV and organ at risk, respectively. Treatment plans were generated by matching multiple isocenter volumetric modulated arc (VMAT) fields of the upper body and multiple isocenter parallel-opposed fields of the lower body. For each plan, 1200 cGy in 8 fractions was prescribed to the wholemore » body volume and the lung dose was constrained to a mean dose of 750 cGy. Such a two-level dose plan was achieved by inverse planning of the torso VMAT fields. For comparison, conventional standing TBI (cTBI) plans were generated on the same whole body CT images at an extended SSD (550cm).The shape of compensators and lung blocks are simulated using body segments and lung contours Compensation was calculated based on the patient CT images, in mimic of the standing TBI treatment. The whole body dose distribution of cTBI plans were calculated with a home-developed GPU Monte Carlo dose engine. Calculated cTBI dose distribution was prescribed to the mid-body point at umbilical level. Results: The VMAT-TBI treatment plans of three patients’ plans achieved 80.2%±5.0% coverage of the total body volume within ±10% of the prescription dose, while cTBI treatment plans achieved 72.2%±4.0% coverage of the total body volume. The averaged mean lung dose of all three patients is lower for VMAT-TBI (7.48 cGy) than for cTBI (8.96 cGy). Conclusion: The proposed patient comfort-oriented VMAT-TBI technique provides for a uniform dose distribution within the total body while reducing the dose to the lungs.« less

A bounding estimate of neutron dose based on measured photon dose around single pass reactors at the Hanford site.

PubMed

Taulbee, Timothy D; Glover, Samuel E; Macievic, Gregory V; Hunacek, Mickey; Smith, Cheryl; DeBord, Gary W; Morris, Donald; Fix, Jack

2010-07-01

Neutron and photon radiation survey records have been used to evaluate and develop a neutron to photon (NP) ratio to reconstruct neutron doses to workers around Hanford's single pass reactors that operated from 1945 to 1972. A total of 5,773 paired neutron and photon measurements extracted from 57 boxes of survey records were used in the development of the NP ratio. The development of the NP ratio enables the use of the recorded dose from an individual's photon dosimeter badge to be used to estimate the unmonitored neutron dose. The Pearson rank correlation between the neutron and photon measurements was 0.71. The NP ratio best fit a lognormal distribution with a geometric mean (GM) of 0.8, a geometric standard deviation (GSD) of 2.95, and the upper 95 th % of this distribution was 4.75. An estimate of the neutron dose based on this NP ratio is considered bounding due to evidence that up to 70% of the total photon exposure received by workers around the single pass reactors occurs during shutdown maintenance and refueling activities when there is no significant neutron exposure. Thus when this NP ratio is applied to the total measured photon dose from an individual film badge dosimeter, the resulting neutron dose is considered bounded.

Assessing anxiety in C57BL/6J mice: a pharmacological characterization of the open-field and light/dark tests.

PubMed

Heredia, Luis; Torrente, Margarita; Colomina, María T; Domingo, José L

2014-01-01

In order to assess anxiety in mammals various tests and species are currently available. These current assays measure changes in anxiety-like behaviors. The open-field and the light/dark are anxiety tests based on the spontaneous behavior of the animals, with C57BL/6J mice being a frequently used strain in behavioral studies. However, the suitability of this strain as a choice in anxiety studies has been questioned. In this study, we performed two pharmacological characterizations of this strain in both the open-field and the light/dark tests. We examined the changes in the anxiety-like behaviors of C57BL/6J mice exposed to chlordiazepoxide (CDP), an anxiolytic drug, at doses of 5 and 10 mg/kg, picrotoxine (PTX), an anxiogenic drug, at doses of 0.5 and 1 mg/kg, and methylphenidate (MPH), a psychomotor stimulant drug, at doses of 5 and 10 mg/kg, in a first experiment. In a second experiment, we tested CDP at 2.5 mg/kg, PTX at 2 mg/kg and MPH at 2.5 mg/kg. Results showed an absence of anxiolytic-like effects of CDP in open-field and light/dark tests. Light/dark test was more sensitive to the anxiogenic effects of PTX than the open-field test. Finally, a clear anxiogenic effect of MPH was observed in the two tests. Although C57BL/6J mice could not be a sensitive model to study anxiolytic effects in pharmacological or behavioral interventions, it might be a suitable model to test anxiogenic effects. Further studies are necessary to corroborate these results. Copyright © 2013 Elsevier Inc. All rights reserved.

Population dose commitments due to radioactive releases from nuclear power plant sites in 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D.A.; Peloquin, R.A.

Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1983. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each of 52 sites. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each of the sites is a histogram showing the fraction of the total population within 2 to 80 km aroundmore » each site receiving various average dose commitments from the airborne pathways. The total dose commitments (from both liquid and airborne pathways) for each site ranged from a high of 45 person-rem to a low of 0.002 person-rem for the sites with plants operating throughout the year with an arithmetic mean of 3 person-rem. The total population dose for all sites was estimated at 170 person-rem for the 100 million people considered at risk.« less

Three-dimensional Čerenkov tomography of energy deposition from ionizing radiation beams.

PubMed

Glaser, Adam K; Voigt, William H A; Davis, Scott C; Zhang, Rongxiao; Gladstone, David J; Pogue, Brian W

2013-03-01

Since its discovery during the 1930s the Čerenkov effect (light emission from charged particles traveling faster than the local speed of light in a dielectric medium) has been paramount in the development of high-energy physics research. The ability of the emitted light to describe a charged particle's trajectory, energy, velocity, and mass has allowed scientists to study subatomic particles, detect neutrinos, and explore the properties of interstellar matter. However, to our knowledge, all applications of the process to date have focused on the identification of particles themselves, rather than their effect upon the surroundings through which they travel. Here we explore a novel application of the Čerenkov effect for the recovery of the spatial distribution of ionizing radiation energy deposition in a medium and apply it to the issue of dose determination in medical physics. By capturing multiple projection images of the Čerenkov light induced by a medical linear accelerator x-ray photon beam, we demonstrate the successful three-dimensional tomographic reconstruction of the imparted dose distribution.

Comparison of light absorption levels with different skin phantoms and the Monte Carlo simulation using Fourier-domain optical coherence tomography

NASA Astrophysics Data System (ADS)

Jo, Hang Chan; Kim, Jae Hun; Kim, Dae Yu

2018-02-01

Dermatologic patients have various skin characteristics such as skin tone and pigmentation color. However most studies on laser ablation and treatment only considered laser operating conditions like wavelength, output power and pulse duration. The laser ablation arises from photothermal effect by photon energy absorption. Chromophores like melanin exist as the absorber in the skin. In this study, we painted color to mimic chromophores on in-vivo and in-vitro skin models to demonstrate influence on the laser ablation by skin color. Water-based pens were used to paint color. Cross sectional images of the laser ablation were acquired by Fourier-domain optical coherence tomography (Fd-OCT). Light source to make ablation was a Q-switch diode-pumped Nd:YVO4 nanosecond laser (532nm central wavelength). Irradiated light energy dose of the laser could not make ablation craters in the control group. However experimental groups showed craters with same irradiation light energy dose. These results show painting on skin increased tissue damage by absorption in painted color without dyeing cells or tissues.

NF-κB is not directly responsible for photoresistance induced by fractionated light delivery in HT-29 colon adenocarcinoma cells.

PubMed

Kuliková, Lucia; Mikeš, Jaromír; Hýžďalová, Martina; Palumbo, Giuseppe; Fedoročko, Peter

2010-01-01

Our recent study follows up an earlier one which demonstrated hypericin-mediated photocytotoxic effects on HT-29 adenocarcinoma cells by light fractionation with a longer dark pause between two unequal light doses (Sackova, A. [2005] Photochem. Photobiol.81, 1411-1416). Here, we present closer study on events invoked by sublethal light dose (1 J cm(-2)) during the period of 6 h that is sufficient to invoke resistance to second lethal dose (11 J cm(-2)). First, we proved that the dark pause of 6 h, but not 1 h, resulted in better cell survival with suppressed phosphatidylserine externalization, decreased reactive oxygen species production and hypericin content as well as altered expression of HSP70, GRP94, clusterin, nuclear factor (NF)-κB, IκB-α or Mcl-1. NF-κB activity assay confirmed activation of this early-response pathway. However, inhibition of IκB (IKK) kinase by parthenolide by stopping NF-κB release from the complex with IκB did not prevent onset of resistance, but it invoked some resistance even in groups with shorter, 1 h dark pause. Therefore, we predict involvement of another signaling pathway, located upstream from NF-κB, responsible for onset of resistance to photodynamic therapy with hypericin in colon adenocarcinoma cells HT-29. © 2010 The Authors. Journal Compilation. The American Society of Photobiology.

Effect of Environmental Conditions and Toxic Compounds on the Locomotor Activity of Pediculus humanus capitis (Phthiraptera: Pediculidae).

PubMed

Ortega-Insaurralde, I; Toloza, A C; Gonzalez-Audino, P; Mougabure-Cueto, G A; Alvarez-Costa, A; Roca-Acevedo, G; Picollo, M I

2015-09-01

In this work, we evaluated the effect of environmental variables such as temperature, humidity, and light on the locomotor activity of Pediculus humanus capitis. In addition, we used selected conditions of temperature, humidity, and light to study the effects of cypermethrin and N,N-diethyl-3-methylbenzamide (DEET) on the locomotor activity of head lice. Head lice increased their locomotor activity in an arena at 30°C compared with activity at 20°C. When we tested the influence of the humidity level, the locomotor activity of head lice showed no significant differences related to humidity level, both at 30°C and 20°C. Concerning light influence, we observed that the higher the intensity of light, the slower the movement of head lice. We also demonstrated that sublethal doses of toxics may alter locomotor activity in adults of head lice. Sublethal doses of cypermethrin induced hyperactivated responses in adult head lice. Sublethal doses of DEET evocated hypoactivated responses in head lice. The observation of stereotyped behavior in head lice elicited by toxic compounds proved that measuring locomotor activity in an experimental set-up where environmental conditions are controlled would be appropriate to evaluate compounds of biological importance, such as molecules involved in the host-parasite interaction and intraspecific relationships. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Population dose commitments due to radioactive releases from nuclear-power-plant sites in 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peloquin, R.A.; Schwab, J.D.; Baker, D.A.

Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1978. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving variousmore » average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 200 person-rem to a low of 0.0004 person-rem with an arithmetic mean of 14 person-rem. The total population dose for allsites was estimated at 660 person-rem for the 93 million people considered at risk. The average individual dose commitment from all pathways on a site basis ranged from a low of 3 x 10/sup -6/ mrem to a high of 0.08 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites.« less

Population dose commitments due to radioactive releases from Nuclear-Power-Plant Sites in 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D.A.; Peloquin, R.A.

Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1979. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ. Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving variousmore » average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 1300 person-rem to a low of 0.0002 person-rem with an arithmetic mean of 38 person-rem. The total population dose for all sites was estimated at 1800 person-rem for the 94 million people considered at risk. The average individual dose commitment from all pathways on a site basis ranged from a low of 2 x 10/sup -6/ mrem to a high of 0.7 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites.« less

Population Dose Commitments Due to Radioactive Releases from Nuclear Power Plant Sites in 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D. A.

Population radiation dose commitments have been estimated from reported radionuclide releases from commercial power reactors operating during 1977. Fifty-year dose commitments from a one-year exposure were calculated from both liquid and atmospheric releases for four population groups (infant, child, teen-ager and adult) residing between 2 and 80 km from each site. This report tabulates the results of these calculations, showing the dose commitments for both liquid and airborne pathways for each age group and organ, Also included for each site is a histogram showing the fraction of the total population within 2 to 80 km around each site receiving variousmore » average dose commitments from the airborne pathways. The total dose commitment from both liquid and airborne pathways ranged from a high of 220 person-rem to a low of 0.003 person-rem with an arithmetic mean of 16 person-rem. The total population dose for all sites was estimated at 700 person-rem for the 92 million people considered at risk. The average individual dose commitment from all pathways on a site basis ranged from a low of 2 x 10{sup -5} mrem to a high of 0.1 mrem. No attempt was made in this study to determine the maximum dose commitment received by any one individual from the radionuclides released at any of the sites.« less

Estimated fluoride doses from toothpastes should be based on total soluble fluoride.

PubMed

Oliveira, Maria José L; Martins, Carolina C; Paiva, Saul M; Tenuta, Livia M A; Cury, Jaime A

2013-11-01

The fluoride dose ingested by young children may be overestimated if based on levels of total fluoride (TF) rather than levels of bioavailable fluoride (total soluble fluoride-TSF) in toothpaste. The aim of the present study was to compare doses of fluoride intake based on TF and TSF. Fluoride intake in 158 Brazilian children aged three and four years was determined after tooth brushing with their usual toothpaste (either family toothpaste (n = 80) or children's toothpaste (n = 78)). The estimated dose (mg F/day/Kg of body weight) of TF or TSF ingested was calculated from the chemical analysis of the toothpastes. Although the ingested dose of TF from the family toothpastes was higher than that from the children's toothpastes (0.074 ± 0.007 and 0.039 ± 0.003 mg F/day/Kg, respectively; p < 0.05), no difference between types of toothpaste was found regarding the ingested dose based on TSF (0.039 ± 0.005 and 0.039 ± 0.005 mg F/day/Kg, respectively; p > 0.05). The fluoride dose ingested by children from toothpastes may be overestimated if based on the TF of the product. This finding suggests that the ingested dose should be calculated based on TSF. Dose of TSF ingested by children is similar whether family or children's toothpaste is used.