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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Common Variants of GSTP1, GSTA1, and TGF{beta}1 are Associated With the Risk of Radiation-Induced Fibrosis in Breast Cancer Patients

Purpose: To provide new insights into the genetic basis of normal tissue radiosensitivity, we evaluated the association between eight polymorphic variants located in six genes related to DNA repair mechanisms, oxidative stress, and fibroblast proliferation (XRCC1 Arg399Gln, XRCC1 Arg194Trp, TP53 Arg72Pro, GSTP1 Ile105Val, GSTA1 C-69T, eNOS G894T, TGF{beta}1 C-509T, and TGF{beta}1 T869C) and the risk of subcutaneous fibrosis in a retrospective series of patients who received radiotherapy after breast-conserving surgery. Methods and Materials: Subcutaneous fibrosis was scored according to the Late Effects of Normal Tissue-Subjective Objective Management Analytical scale in 257 breast cancer patients who underwent surgery plus adjuvant radiotherapy. Genotyping was conducted by polymerase chain reaction-restriction fragment length polymorphism analysis on genomic DNA extracted from peripheral blood. The association between genetic variants and the risk of moderate to severe fibrosis was evaluated by binary logistic regression analysis. Results: Two hundred thirty-seven patients were available for the analysis. Among them, 41 patients (17.3%) developed moderate to severe fibrosis (Grade 2-3), and 196 (82.7%) patients displayed no or minimal fibrotic reactions (Grade 0-1). After adjustment of confounding factors, GSTP1 Ile105Val (odds ratio [OR] 2.756; 95% CI, 1.188-6.393; p = 0.018), GSTA1 C-69T (OR 3.223; 95% CI, 1.176-8.826; p = 0.022), and TGF{beta}1 T869C (OR 0.295; 95% CI, 0.090-0.964; p = 0.043) polymorphisms were found to be significantly associated with the risk of Grade 2-3 radiation-induced fibrosis. In the combined analysis, carriers of three risk genotypes were found to be at higher odds for the development of Grade 2-3 fibrosis than were patients with two risk genotypes (OR 4.415; 95% CI, 1.553-12.551, p = 0.005) or with no or one risk genotype (OR 8.563; 95% CI, 2.671-27.447; p = 0.0003). Conclusions: These results suggest that functional variations in genes involved in oxidative stress response and fibroblast proliferation may modulate the development of radiation-induced fibrosis in breast cancer patients. The results of the combined analysis support the notion that approaches based on the combination of different genetic markers have the potential to predict normal tissue responses.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Combinations of NIR, Raman spectroscopy and physicochemical measurements for improved monitoring of solvent extraction processes using hierarchical multivariate analysis models

The reliability of chemical processes can be greatly improved by implementing inline monitoring systems. Combining multivariate analysis with non-destructive sensors can enhance the process without interfering with the operation. Here, we present here hierarchical models using both principal component analysis and partial least square analysis developed for different chemical components representative of solvent extraction process streams. A training set of 380 samples and an external validation set of 95 samples were prepared and Near infrared and Raman spectral data as well as conductivity under variable temperature conditions were collected. The results from the models indicate that careful selection of the spectral range is important. By compressing the data through Principal Component Analysis (PCA), we lower the rank of the data set to its most dominant features while maintaining the key principal components to be used in the regression analysis. Within the studied data set, concentration of five chemical components were modeled; total nitrate (NO 3 - ), total acid (H + ), neodymium (Nd 3+ ), sodium (Na + ), and ionic strength (I.S.). The best overall model prediction for each of the species studied used a combined data set comprised of complementary techniques including NIR, Raman, and conductivity. Finally, our study shows that chemometric models are powerful but requires significant amount of carefully analyzed data to capture variations in the chemistry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

A data-driven approach to construct a quantitative relationship between microstructural features of fatigue cracks and contact acoustic nonlinearity

This study demonstrates the feasibility of a data-driven approach to construct a quantitative relationship between nonlinear acoustic parameters and microstructural features of contact interfaces. The near-surface nonlinearity is measured using dynamic acousto-elastic testing (DAET) with a surface wave probe, while the microstructural features are extracted from scanning electron microscopy (SEM) images of fatigue cracks. Four aluminum alloy samples, each having a fatigue crack are prepared. Six local nonlinearity parameters are measured at different locations along the crack propagation direction. A total of 40 local measurements are acquired. A principal component analysis (PCA) reveals that all six nonlinearity parameters are correlated and hence can be replaced by one principal component (PC). Fifteen crack micro-geometrical features at each measurement point were extracted from the SEM images. Regression analysis is used to relate the PC of the nonlinearity parameters to the microstructural features at the crack interface. We compare three regression models that take variable selection into account: stepwise multiple linear regression (MLR), stepwise principal component regression (PCR), and least absolute shrinkage and selection operator (LASSO). Despite having different principles, the three predictive models identify two features as the most significant in predicting the interface nonlinearity: the crack aperture (opening) distribution and the distance to the crack tip. The differences between the three models and the physical interpretation of the data-driven predictions are discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Brachial Plexus-Associated Neuropathy After High-Dose Radiation Therapy for Head-and-Neck Cancer

Purpose: To identify clinical and treatment-related predictors of brachial plexus-associated neuropathies after radiation therapy for head-and-neck cancer. Methods and Materials: Three hundred thirty patients who had previously completed radiation therapy for head-and-neck cancer were prospectively screened using a standardized instrument for symptoms of neuropathy thought to be related to brachial plexus injury. All patients were disease-free at the time of screening. The median time from completion of radiation therapy was 56 months (range, 6-135 months). One-hundred fifty-five patients (47%) were treated by definitive radiation therapy, and 175 (53%) were treated postoperatively. Radiation doses ranged from 50 to 74 Gy (median, 66 Gy). Intensity-modulated radiation therapy was used in 62% of cases, and 133 patients (40%) received concurrent chemotherapy. Results: Forty patients (12%) reported neuropathic symptoms, with the most common being ipsilateral pain (50%), numbness/tingling (40%), motor weakness, and/or muscle atrophy (25%). When patients with <5 years of follow-up were excluded, the rate of positive symptoms increased to 22%. On univariate analysis, the following factors were significantly associated with brachial plexus symptoms: prior neck dissection (p = 0.01), concurrent chemotherapy (p = 0.01), and radiation maximum dose (p < 0.001). Cox regression analysis confirmed that both neck dissection (p < 0.001) and radiation maximum dose (p < 0.001) were independently predictive of symptoms. Conclusion: The incidence of brachial plexus-associated neuropathies after radiation therapy for head-and-neck cancer may be underreported. In view of the dose-response relationship identified, limiting radiation dose to the brachial plexus should be considered when possible.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Lifestyle Factors in U.S. Residential Electricity Consumption

A multivariate statistical approach to lifestyle analysis of residential electricity consumption is described and illustrated. Factor analysis of selected variables from the 2005 U.S. Residential Energy Consumption Survey (RECS) identified five lifestyle factors reflecting social and behavioral choices associated with air conditioning, laundry usage, personal computer usage, climate zone of residence, and TV use. These factors were also estimated for 2001 RECS data. Multiple regression analysis using the lifestyle factors yields solutions accounting for approximately 40% of the variance in electricity consumption for both years. By adding the associated household and market characteristics of income, local electricity price and access to natural gas, variance accounted for is increased to approximately 54%. Income contributed only {approx}1% unique variance to the 2005 and 2001 models, indicating that lifestyle factors reflecting social and behavioral choices better account for consumption differences than income. This was not surprising given the 4-fold range of energy use at differing income levels. Geographic segmentation of factor scores is illustrated, and shows distinct clusters of consumption and lifestyle factors, particularly in suburban locations. The implications for tailored policy and planning interventions are discussed in relation to lifestyle issues.

03 NATURAL GAS↗
DOE OSTI2016

Multivariate analysis for the estimation of target localization errors in fiducial marker-based radiotherapy

Purpose: To assess the target localization error (TLE) in terms of the distance between the target and the localization point estimated from the surrogates (|TMD|), the average of respiratory motion for the surrogates and the target (|aRM|), and the number of fiducial markers used for estimating the target (n). Methods: This study enrolled 17 lung cancer patients who subsequently underwent four fractions of real-time tumor tracking irradiation. Four or five fiducial markers were implanted around the lung tumor. The three-dimensional (3D) distance between the tumor and markers was at maximum 58.7 mm. One of the markers was used as the target (P{sub t}), and those markers with a 3D |TMD{sub n}| ≤ 58.7 mm at end-exhalation were then selected. The estimated target position (P{sub e}) was calculated from a localization point consisting of one to three markers except P{sub t}. Respiratory motion for P{sub t} and P{sub e} was defined as the root mean square of each displacement, and |aRM| was calculated from the mean value. TLE was defined as the root mean square of each difference between P{sub t} and P{sub e} during the monitoring of each fraction. These procedures were performed repeatedly using the remaining markers. To provide the best guidance on the answer with n and |TMD|, fiducial markers with a 3D |aRM ≥ 10 mm were selected. Finally, a total of 205, 282, and 76 TLEs that fulfilled the 3D |TMD| and 3D |aRM| criteria were obtained for n = 1, 2, and 3, respectively. Multiple regression analysis (MRA) was used to evaluate TLE as a function of |TMD| and |aRM| in each n. Results: |TMD| for n = 1 was larger than that for n = 3. Moreover, |aRM| was almost constant for all n, indicating a similar scale for the marker’s motion near the lung tumor. MRA showed that |aRM| in the left–right direction was the major cause of TLE; however, the contribution made little difference to the 3D TLE because of the small amount of motion in the left–right direction. The TLE calculated from the MRA ({sup MRA}TLE) increased as |TMD| and |aRM| increased and adversely decreased with each increment of n. The median 3D {sup MRA}TLE was 2.0 mm (range, 0.6–4.3 mm) for n = 1, 1.8 mm (range, 0.4–4.0 mm) for n = 2, and 1.6 mm (range, 0.3–3.7 mm) for n = 3. Although statistical significance between n = 1 and n = 3 was observed in all directions, the absolute average difference and the standard deviation of the {sup MRA}TLE between n = 1 and n = 3 were 0.5 and 0.2 mm, respectively. Conclusions: A large |TMD| and |aRM| increased the differences in TLE between each n; however, the difference in 3D {sup MRA}TLEs was, at most, 0.6 mm. Thus, the authors conclude that it is acceptable to continue fiducial marker-based radiotherapy as long as |TMD| is maintained at ≤58.7 mm for a 3D |aRM| ≥ 10 mm.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Pretreatment Nomogram to Predict the Risk of Acute Urinary Retention After I-125 Prostate Brachytherapy

Purpose: Acute urinary retention (AUR) after iodine-125 (I-125) prostate brachytherapy negatively influences long-term quality of life and therefore should be prevented. We aimed to develop a nomogram to preoperatively predict the risk of AUR. Methods: Using the preoperative data of 714 consecutive patients who underwent I-125 prostate brachytherapy between 2005 and 2008 at our department, we modeled the probability of AUR. Multivariate logistic regression analysis was used to assess the predictive ability of a set of pretreatment predictors and the additional value of a new risk factor (the extent of prostate protrusion into the bladder). The performance of the final model was assessed with calibration and discrimination measures. Results: Of the 714 patients, 57 patients (8.0%) developed AUR after implantation. Multivariate analysis showed that the combination of prostate volume, IPSS score, neoadjuvant hormonal treatment and the extent of prostate protrusion contribute to the prediction of AUR. The discriminative value (receiver operator characteristic area, ROC) of the basic model (including prostate volume, International Prostate Symptom Score, and neoadjuvant hormonal treatment) to predict the development of AUR was 0.70. The addition of prostate protrusion significantly increased the discriminative power of the model (ROC 0.82). Calibration of this final model was good. The nomogram showed that among patients with a low sum score (<18 points), the risk of AUR was only 0%-5%. However, in patients with a high sum score (>35 points), the risk of AUR was more than 20%. Conclusion: This nomogram is a useful tool for physicians to predict the risk of AUR after I-125 prostate brachytherapy. The nomogram can aid in individualized treatment decision-making and patient counseling.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2011

Radiotherapy in the Treatment of Patients With Unresectable Extrahepatic Cholangiocarcinoma

Purpose: Extrahepatic cholangiocarcinoma is an uncommon but lethal malignancy. We analyzed the role of definitive chemoradiotherapy for patients with nonmetastatic, locally advanced extrahepatic cholangiocarcinoma treated at a single institution. Methods and Materials: This retrospective analysis included 37 patients who underwent external beam radiation therapy (EBRT) with concurrent chemotherapy and/or brachytherapy (BT) for locally advanced extrahepatic cholangiocarcinoma. Local control (LC) and overall survival (OS) were assessed, and univariate regression analysis was used to evaluate the effects of patient- and treatment-related factors on clinical outcomes. Results: Twenty-three patients received EBRT alone, 8 patients received EBRT plus BT, and 6 patients received BT alone (median follow-up of 14 months). Two patients were alive without evidence of recurrence at the time of analysis. Actuarial OS and LC rates at 1 year were 59% and 90%, respectively, and 22% and 71%, respectively, at 2 years. Two patients lived beyond 5 years without evidence of recurrence. On univariate analysis, EBRT with or without BT improved LC compared to BT alone (97% vs. 56% at 1 year; 75% vs. 56% at 2 years; p = 0.096). Patients who received EBRT alone vs. BT alone also had improved LC (96% vs. 56% at 1 year; 80% vs. 56% at 2 years; p = 0.113). Age, gender, tumor location (proximal vs. distal), histologic differentiation, EBRT dose ({<=} or >50 Gy), EBRT planning method (two-dimensional vs. three-dimensional), and chemotherapy were not associated with patient outcomes. Conclusions: Patients with locally advanced extrahepatic cholangiocarcinoma have poor survival. Long-term survival is rare. The majority of patients treated with EBRT had local control at the time of death, suggesting that symptoms due to the local tumor effect might be effectively controlled with radiation therapy, and EBRT is an important element of treatment. Novel treatment approaches are indicated in the therapy for this disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Acoustic Imaging Evaluation of Juvenile Salmonid Behavior in the Immediate Forebay of the Water Temperature Control Tower at Cougar Dam, 2010

This report presents the results of an evaluation of juvenile Chinook salmon (Oncorhynchus tshawytscha) behavior at Cougar Dam on the south fork of the McKenzie River in Oregon in 2010. The study was conducted by the Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers (USACE). The overall goal of the study was to characterize juvenile salmonid behavior and movement patterns in the immediate forebay of the Water Temperature Control (WTC) tower of the dam for USACE and fisheries resource managers use in making decisions about bioengineering designs for long-term structures and/or operations to facilitate safe downstream passage for juvenile salmonids. We collected acoustic imaging (Dual-Frequency Identification Sonar; DIDSON) data from March 1, 2010, through January 31, 2011. Juvenile salmonids (hereafter, called 'fish') were present in the immediate forebay of the WTC tower throughout the study. Fish abundance index was low in early spring (<200 fish per sample-day), increased in late April, and peaked on May 19 (6,039 fish). A second peak was observed on June 6 (2904 fish). Fish abundance index decreased in early June and remained low in the summer months (<100 fish per sample-day). During the fall and winter, fish numbers varied with a peak on November 10 (1881 fish) and a minimum on December 7 (12 fish). A second, smaller, peak occurred on December 22 (607 fish). A univariate statistical analysis indicated fish abundance index (log10-transformed) was significantly (P<0.05) positively correlated with forebay elevation, velocity over the WTC tower intake gate weirs, and river flows into the reservoir. A subsequent multiple regression analysis resulted in a model (R2=0.70) predicting fish abundance (log-transformed index values) using two independent variables of mean forebay elevation and the log10 of the forebay elevation range. From the approximate fish length measurements made using the DIDSON imaging software, the average fish length during early spring 2010 was 214 ± 86 mm (standard deviation). From May through early November, the average fish length remained relatively consistent (132 ± 54 mm), after which average lengths increased to 295 ± 148 mm for mid-November though early December. From mid-December through January the average fish length decreased to 151 76 mm. Milling in front of the WTC tower was the most common fish behavior observed throughout the study period. Traversing along the front of the tower, east-to-west and west-to-east, was the next common behavior. The percentage of fish events showing movement from the forebay to the tower or from the tower to the forebay was generally low throughout the spring, summer, and early fall (0 to 30% for both directions combined, March through early November). From mid-November 2010 through the end of the study (January 31, 2011), the combined percentages of fish moving into and out of the tower were higher (25 to 70%) than during previous months of the study. Schooling behavior was most distinct in the spring. Schooling events were present in 30 to 96% of the fish events during that period, with a peak on May 19. Schooling events were also present in the summer, but at lower numbers. With the exception of some schooling in mid-December, few to no schooling events were observed in the fall and winter months. Diel distributions for schooling fish during spring and fall months indicate schooling was concentrated during daylight hours and no schooling was observed at night. However, in December, schooling occurred at night, after midnight, and during daylight hours. Predator activity, most likely bull trout or rainbow trout according to a USACE biologist, was observed during late spring, when fish abundance index and schooling were highest for the year, and again in the fall months when fish events increased from a summer low. No predator activity was observed in the summer, and little activity occurred during the winter months.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2011

Acute Urinary Retention After I-125 Prostate Brachytherapy in Relation to Dose in Different Regions of the Prostate

Purpose: To assess the influence of dose in different prostate regions, and the influence of anatomic variation on the risk of acute urinary retention (AUR) after I-125 prostate brachytherapy. Methods and Materials: In this case-control study, dosimetry and anatomy were compared between 50 patients with AUR (cases) and 50 patients without AUR (controls). Cases and controls were randomly selected from our database. The following structures were delineated on magnetic resonance imaging: prostate, urethra, peripheral zone, transitional zone, apex, base, midprostate, lower sphincter, and bladder neck. The dosimetric parameters analyzed were D{sub 10}, D{sub 50}, D{sub 90}, V{sub 100}, V{sub 150}, and V{sub 200}. The anatomic parameters analyzed were prostate protrusion into the bladder, bladder overlap, urethra angle, and urethra-bladder angle. The delineator was blinded to the patient's AUR status. Logistic regression analysis was used to investigate the association of these factors with AUR. Results: The dose delivered to different regions of the prostate was not significantly associated with the risk of AUR. Only dose to the bladder neck was significantly associated with AUR (odds ratio 1.13 per 10 Gy; 95% CI 1.02;1.26; p = 0.023). Mean bladder neck D{sub 90} was 65 Gy in AUR cases vs. 56 Gy in controls (p = 0.016), and mean bladder neck D{sub 10} was 128 Gy vs. 107 Gy, respectively (p = 0.018). Furthermore, on univariate analysis, a larger extent of both bladder overlap and of prostate protrusion were associated with a higher risk of AUR (odds ratio 1.16; 95% CI 1.04-1.28; p = 0.005, and odds ratio 1.83; 95% CI 1.37-2.45; p < 0.001, respectively). The mean extent of prostate protrusion was 3.5 mm in AUR cases vs. 1.0 mm in controls (p < 0.001). Odds ratios did not change substantially after adjustment for potential confounders. On multivariate analysis, the extent of prostate protrusion seemed to be a stronger risk factor for AUR than bladder overlap. Conclusion: The risk of AUR is not associated with dose delivered to different regions of the prostate. However, a higher dose to the bladder neck and a larger extent of prostate protrusion into the bladder are risk factors for the development of AUR after I-125 prostate brachytherapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2012

Propensity Score-based Comparison of Long-term Outcomes With 3-Dimensional Conformal Radiotherapy vs Intensity-Modulated Radiotherapy for Esophageal Cancer

Purpose: Although 3-dimensional conformal radiotherapy (3D-CRT) is the worldwide standard for the treatment of esophageal cancer, intensity modulated radiotherapy (IMRT) improves dose conformality and reduces the radiation exposure to normal tissues. We hypothesized that the dosimetric advantages of IMRT should translate to substantive benefits in clinical outcomes compared with 3D-CRT. Methods and Materials: An analysis was performed of 676 nonrandomized patients (3D-CRT, n=413; IMRT, n=263) with stage Ib-IVa (American Joint Committee on Cancer 2002) esophageal cancers treated with chemoradiotherapy at a single institution from 1998-2008. An inverse probability of treatment weighting and inclusion of propensity score (treatment probability) as a covariate were used to compare overall survival time, interval to local failure, and interval to distant metastasis, while accounting for the effects of other clinically relevant covariates. The propensity scores were estimated using logistic regression analysis. Results: A fitted multivariate inverse probability weighted-adjusted Cox model showed that the overall survival time was significantly associated with several well-known prognostic factors, along with the treatment modality (IMRT vs 3D-CRT, hazard ratio 0.72, P<.001). Compared with IMRT, 3D-CRT patients had a significantly greater risk of dying (72.6% vs 52.9%, inverse probability of treatment weighting, log-rank test, P<.0001) and of locoregional recurrence (P=.0038). No difference was seen in cancer-specific mortality (Gray's test, P=.86) or distant metastasis (P=.99) between the 2 groups. An increased cumulative incidence of cardiac death was seen in the 3D-CRT group (P=.049), but most deaths were undocumented (5-year estimate, 11.7% in 3D-CRT vs 5.4% in IMRT group, Gray's test, P=.0029). Conclusions: Overall survival, locoregional control, and noncancer-related death were significantly better after IMRT than after 3D-CRT. Although these results need confirmation, IMRT should be considered for the treatment of esophageal cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2014

Reverberation measurements of the inner radius of the dust torus in 17 Seyfert galaxies

We present the results of a dust reverberation survey for 17 nearby Seyfert 1 galaxies, which provides the largest homogeneous data collection for the radius of the innermost dust torus. A delayed response of the K-band light curve after the V-band light curve was found for all targets, and 49 measurements of lag times between the flux variation of the dust emission in the K band and that of the optical continuum emission in the V band were obtained by the cross-correlation function analysis and also by an alternative method for estimating the maximum likelihood lag. The lag times strongly correlated with the optical luminosity in the luminosity range of M{sub V} = –16 to –22 mag, and the regression analysis was performed to obtain the correlation log Δt (days) = –2.11 – 0.2 M{sub V} assuming Δt∝L {sup 0.5}, which was theoretically expected. We discuss the possible origins of the intrinsic scatter of the dust lag-luminosity correlation, which was estimated to be approximately 0.13 dex, and we find that the difference of internal extinction and delayed response of changes in lag times to the flux variations could have partly contributed to intrinsic scatter. However, we could not detect any systematic change of the correlation with the subclass of the Seyfert type or the Eddington ratio. Finally, we compare the dust reverberation radius with the near-infrared interferometric radius of the dust torus and the reverberation radius of broad Balmer emission lines. The interferometric radius in the K band was found to be systematically larger than the dust reverberation radius in the same band by the about a factor of two, which could be interpreted by the difference between the flux-weighted radius and response-weighted radius of the innermost dust torus. The reverberation radius of the broad Balmer emission lines was found to be systematically smaller than the dust reverberation radius by about a factor of four to five, which strongly supports the unified scheme of the Seyfert type of active galactic nuclei (AGNs). Moreover, we examined the radius-luminosity correlations for the hard X-ray (14-195 keV) and the [O IV] λ25.89 μm emission-line luminosities, which would be applicable for obscured AGNs.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

Type II and type III radio bursts and their correlation with solar energetic proton events

Using the Wind/WAVES radio observations from 2010 to 2013, we present an analysis of the 123 decametric–hectometric (DH) type II solar radio bursts during this period, the associated type III burst properties, and their correlation with solar energetic proton (SEP) properties determined from analysis of the Geostationary Operational Environmental Satellite (GOES) observations. We present a useful catalog of the type II burst, type III burst, Langmuir wave, and proton flux properties for these 123 events, which we employ to develop a statistical relationship between the radio properties and peak proton flux that can be used to forecast SEP events. We find that all SEP events with a peak >10 MeV flux above 15 protons cm{sup −2} s{sup −1} sr{sup −1} are associated with a type II burst and virtually all SEP events, 92%, are also associated with a type III radio burst. Based on a principal component analysis, the radio burst properties that are most highly correlated with the occurrence of gradual SEP events and account for the most variance in the radio properties are the type III burst intensity and duration. Further, a logistic regression analysis with the radio-derived principal component (dominated by the type III and type II radio burst intensity and type III duration) obtains SEP predictions approaching the human forecaster rates, with a false alarm rate of 22%, a probability of detection of 62%, and with 85% of the classifications correct. Therefore, type III radio bursts that occur along with a DH type II burst are shown to be an important diagnostic that can be used to forecast SEP events.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

Use of 4-Dimensional Computed Tomography-Based Ventilation Imaging to Correlate Lung Dose and Function With Clinical Outcomes

Purpose: Four-dimensional computed tomography (4DCT)-based ventilation is an emerging imaging modality that can be used in the thoracic treatment planning process. The clinical benefit of using ventilation images in radiation treatment plans remains to be tested. The purpose of the current work was to test the potential benefit of using ventilation in treatment planning by evaluating whether dose to highly ventilated regions of the lung resulted in increased incidence of clinical toxicity. Methods and Materials: Pretreatment 4DCT data were used to compute pretreatment ventilation images for 96 lung cancer patients. Ventilation images were calculated using 4DCT data, deformable image registration, and a density-change based algorithm. Dose–volume and ventilation-based dose function metrics were computed for each patient. The ability of the dose–volume and ventilation-based dose–function metrics to predict for severe (grade 3+) radiation pneumonitis was assessed using logistic regression analysis, area under the curve (AUC) metrics, and bootstrap methods. Results: A specific patient example is presented that demonstrates how incorporating ventilation-based functional information can help separate patients with and without toxicity. The logistic regression significance values were all lower for the dose–function metrics (range P=.093-.250) than for their dose–volume equivalents (range, P=.331-.580). The AUC values were all greater for the dose–function metrics (range, 0.569-0.620) than for their dose–volume equivalents (range, 0.500-0.544). Bootstrap results revealed an improvement in model fit using dose–function metrics compared to dose–volume metrics that approached significance (range, P=.118-.155). Conclusions: To our knowledge, this is the first study that attempts to correlate lung dose and 4DCT ventilation-based function to thoracic toxicity after radiation therapy. Although the results were not significant at the .05 level, our data suggests that incorporating ventilation-based functional imaging can improve prediction for radiation pneumonitis. We present an important first step toward validating the use of 4DCT-based ventilation imaging in thoracic treatment planning.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

A tight L{sub iso}–E{sub p,z}–Γ{sub 0} correlation of gamma-ray bursts

We select a sample of 34 gamma-ray bursts (GRBs) whose Γ{sub 0} values are derived with the onset peaks observed in the afterglow light curves (except for GRB 060218, whose Γ{sub 0} is estimated with its radio data), and investigate the correlations among Γ{sub 0}, the isotropic peak luminosity (L{sub iso}), and the peak energy (E{sub p,z}) of the νf{sub ν} spectrum in the cosmological rest frame. An analysis of pair correlations among these observables well confirms the results reported by the previous papers. More interestingly, a tight correlation among L{sub iso}, E{sub p,z}, and Γ{sub 0} is found from a multiple regression analysis, which takes the form of L{sub iso}∝E{sub p,z}{sup 1.34±0.14}Γ{sub 0}{sup 1.32±0.19} or E{sub p,z}∝L{sub iso}{sup 0.55±0.06}Γ{sub 0}{sup −0.50±0.17}. Nine other GRBs whose Γ{sub 0} are derived via the pair production opacity constraint also follow such a correlation. Excluding GRB 060218, the L{sub iso}−E{sub p,z}−Γ{sub 0} correlation is valid, and it even holds in the jet co-moving frame. However, GRB 060218 deviates the L{sub iso}{sup ′}−E{sub p}{sup ′} relation of typical GRBs in the jet co-moving frame with 3σ. We argue that the L{sub iso}−E{sub p,z}−Γ{sub 0} correlation may be more physical than the L{sub iso}−E{sub p,z} correlation, since physically the relationship between the observed L{sub iso} and E{sub p,z} not only depends on radiation physics, but also depends on the bulk motion of the jet. We explore the possible origins of this correlation and discuss its physical implications for understanding GRB jet composition and radiation mechanisms.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2018

X-ray Diffraction Investigation of Annealing Behavior of Peened Surface Deformation Layer on Precipitation Hardening Stainless Steel

In order to investigate the recrystallization behavior of peened surface deformation layer of precipitation hardening stainless steel, a classic x-ray diffraction line profile analysis, Voigt method, was carried out on peened 17-4PH with different isothermal annealing temperatures. The activation energy of domain boundary migration (Q{sub a}) and the activation energy of microstrain relaxation (Q{sub b}) were calculated by regression analysis in different annealing temperature conditions. The results show that the value of Q{sub a} decreases with annealing temperature increasing, which is due to the influence of precipitation (ε-Cu) size on the movements of grain and subgrain boundaries. The maximum growth rate of ε-Cu particles occurs during 400 to 500 °C interval. Compared with growth behavior of domain size, microstrain relaxation behavior is less sensitive to precipitation particle size. The effects of annealing temperature and time on dislocation density are both significant when annealing temperature is lower than 500 °C. However, the effect of annealing temperature on dislocation density becomes insignificant when annealing temperature is higher than 500 °C. 300 °C annealing temperature only leads to the microstrain relaxation but nearly cannot lead to the domain size growth even if prolonging annealing time. Microstructure enhancement effect still exists in plastic deformation layer when 300 °C annealing temperature lasts for 60 min but nearly disappears when 600 °C annealing temperature lasts for 20 min.

36 MATERIALS SCIENCE↗