47 research outputs found
Twisting Flux Tubes as a cause of Micro-Flaring Activity
High-cadence optical observations of an H-alpha blue-wing bright point near
solar AR NOAA 10794 are presented. The data were obtained with the Dunn Solar
Telescope at the National Solar Observatory/Sacramento Peak using a newly
developed camera system, the Rapid Dual Imager. Wavelet analysis is undertaken
to search for intensity-related oscillatory signatures, and periodicities
ranging from 15 to 370 s are found with significance levels exceeding 95%.
During two separate microflaring events, oscillation sites surrounding the
bright point are observed to twist. We relate the twisting of the oscillation
sites to the twisting of physical flux tubes, thus giving rise to reconnection
phenomena. We derive an average twist velocity of 8.1 km/s and detect a peak in
the emitted flux between twist angles of 180 and 230 degrees.Comment: 8 pages, 10 figure
Natural radioactivity of barite concrete shields containing commonly used supplementary materials
WOS: 000514758800011The recycling of hazardous materials within new composites has a sustainable importance as it contributes on the reduction of high radionuclide concentrations. in this study, the effect of cementitious materials i.e. viscosity modifier, silica fume and fly ash on the Ra-226, Th-232 and K-40 activity levels of barite concrete shields was researched by using different mixing compositions in terms of binder content, w/b ratio and the amount of supplementary cementitious materials. in comparison to cement, silica fume and fly ash used in the production of concrete shields were found to have significantly higher activity levels of K-40, as well as Ra-226, Th-232 and K-40, respectively. the Ra-226, Th-232 and K-40 activity levels of concrete shields range between 2.2 and 20.7 Bq kg(-1); 2.6 and 7.0 Bq kg(-1); 51.5 and 89.3 Bq kg(-1), respectively. These activity values were found similar or less than those of building materials in the world. These satisfactory results are mostly caused by the barite source which has lower radioactivity levels. the concrete mixture details used in the study caused significant variation in the natural radioactivity of barite concrete shields. the introduction of silica fume which has high K-40 activity levels and fly ash with high Ra-226, Th-232 and K-40 activity levels compared to cement and barite aggregate, significantly increased the radiological hazard parameters, although all results were found to be below the limits recommended by international reports. in conclusion. Ra-226 activity levels of the concrete shields were significantly increased (up to 8.4 times) by the variation of mix design parameters used in comparison with concrete mixtures that have the least Ra-226 activity level. the Th-232 and K-40 activity levels were as well increased in relatively less amounts (1.7 and 0.73 times higher, respectively). (C) 2019 Elsevier Ltd. All rights reserved
Lycopene in the Prevention of Radiation-Induced Esophagitis
PubMedID: 28094572We aimed to research whether lycopene (L) could prevent radiation-induced acute esophageal toxicity in Wistar albino rats. 60 rats were placed in five groups as follows: control, L, radiotherapy (RT), L before RT (L + RT), and L before and after RT (L + RT + L). 6 mg/kg bw/day L was administered 7 days in the L group, 7 days before RT in the L + RT group, and 7 days before and after in the L + RT + L group. 35 Gy thoracic RT was performed. Serum L levels were measured, and the esophagi were evaluated histopathologically for intraepithelial degenerative changes-necrosis, vacuole formation, inflammation, regeneration-mitosis, and subepithelial bulla formation. L levels were significantly higher in the L receiving groups. All histopathologic results were significantly worse in the RT group than in the none-RT groups. The L + RT and the L + RT + L groups had better results than the RT group. Grade 2–3 degenerative changes-necrosis and vacuole formation were significantly lesser in the L + RT and the L + RT + L groups than those in the RT group. There was a trend toward decreased subepithelial bulla formation and inflammation in the L + RT and the L + RT + L groups compared to the RT group. Regeneration-mitosis was insignificantly lesser in the L + RT and significantly fewer in the L + RT + L groups than that in the RT group. © 2017 Taylor & Francis Group, LLC
Influence of Breast Reconstruction on Postmastectomy Radiotherapy: Global Perceptions and Practice Patterns
52nd Annual Meeting of the American-Society-For-Radiation-Oncology -- OCT 31-NOV 04, 2010 -- San Diego, CAWOS: 000288775700505…Amer Soc Radiation Onco
Treatment adherence and outcome in women with inflammatory breast cancer: Does race matter?
PubMedID: 21692059BACKGROUND: The authors compared treatment adherence rates and outcome in Caucasian and African American patients with inflammatory breast cancer (IBC). METHODS: The records of 55 (25 Caucasian and 30 African American) IBC patients treated with curative intent from 1995 to 2009 were reviewed. All patients received neoadjuvant doxorubicin (Adriamycin) and/or taxane-based chemotherapy, and mastectomy with or without radiotherapy. The median follow-up period for Caucasian and African American patients was similar (39.5 months and 36.1 months, respectively). RESULTS: There was no difference between races in median age, tumor size, grade, and receptor status at diagnosis. The number of patients who completed neoadjuvant chemotherapy, surgery, and radiotherapy did not differ by race (84% of Caucasians vs 86.7% of African Americans) nor did the median length of time to complete trimodality treatment (263 [range, 207-422] days for Caucasians vs 262 [range, 165-371] days for African Americans). There was a trend toward slightly higher pathological complete response rates in Caucasian than African American women (20% in Caucasians vs 6.7% in African Americans, P =.23). Despite slightly better response rates to neoadjuvant chemotherapy, Caucasian patients did not have higher 3-year local control rates (70% in Caucasians vs 64% in African Americans, P =.73). However, there was a trend toward higher 3-year overall survival in Caucasian versus African American patients (73% in Caucasians vs 55% in African Americans, P =.09) and higher distant metastasis-free survival (60% in Caucasians vs 40% in African Americans, P =.19). CONCLUSIONS: This study is among the largest to examine patients with IBC by race. Being Caucasian or African American did not appear to impact treatment adherence. However, African American patients tended to have poorer response to standard treatment and worse outcome than Caucasian patients. Copyright © 2011 American Cancer Society
Definitive external-beam radiotherapy versus radical prostatectomy in clinically localized high-risk prostate cancer: A retrospective study
PubMedID: 30611260Background: Optimal treatment of high-risk prostate cancer remains controversial. We aimed to compare treatment outcomes of prostate cancer patients treated with definitive external-beam radiotherapy (ExRT) or radical prostatectomy (RP). Methods: The records of 120 high-risk clinical stage T2b-T4 N0 M0 prostate cancer patients treated with definitive ExRT or RP were reviewed. Patients with pretreatment prostate-specific antigen (PSA) levels ?20 ng/mL or clinical ?T3 stage or Gleason score (GS) ?8 were included in the study. Biochemical failure free survival (BFFS), distant metastasis free survival (DMFS), cancer-specific survival (CSS) and overall survival (OS) were analyzed. Cox regression analysis was performed to determine predictors of BF. Results: Seventy-two patients received definitive ExRT with androgen-deprivation therapy in 95.8% and 48 patients underwent RP with pelvic lymph node dissection. Mean age (67.7 ± 6.6 vs 64.5 ± 7.6 year, p = 0.017) and the rate of patients with PSA levels ?20 ng/mL (69.4% vs 47.9%, p = 0.022) were higher in the definitive ExRT group than the RP group. Distributions of GS and clinical T stage were similar. Mean follow-up was 60.2 ± 30.3 months in the definitive ExRT group and 41.3 ± 21.5 months in the RP group (p < 0.001). Twenty-five % of the RP group received adjuvant ExRT and 41.7% received salvage ExRT. Biochemical failure was significantly higher (52.1% vs 21.4%, p < 0.001) and the mean BFFS was significantly lesser (34.4 ± 3.9 vs 97.8 ± 5.9 months, p < 0.001) in the RP group than the definitive ExRT group. However, DMFS, CSS and OS were similar in both groups. In multivariate analysis, being in the RP group significantly increased the risk of BF (p < 0.001). Furthermore, not receiving pelvic lymphatic irradiation in the definitive ExRT group (p = 0.048) and having positive surgical margin in the RP group (p = 0.050) increased the risk of BF. Conclusions: BF was significantly higher and the mean BFFS was significantly lesser in high-risk prostate cancer patients undergoing RP than definitive ExRT while DMFS, CSS and OS were similar in both treatment groups. © 2019 The Author(s)