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All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Switchgrass Genomic Diversity, Ploidy, and Evolution: Novel Insights from a Network-Based SNP Discovery Protocol

Switchgrass (Panicum virgatum L.) is a perennial grass that has been designated as an herbaceous model biofuel crop for the United States of America. To facilitate accelerated breeding programs of switchgrass, we developed both an association panel and linkage populations for genome-wide association study (GWAS) and genomic selection (GS). All of the 840 individuals were then genotyped using genotyping by sequencing (GBS), generating 350 GB of sequence in total. As a highly heterozygous polyploid (tetraploid and octoploid) species lacking a reference genome, switchgrass is highly intractable with earlier methodologies of single nucleotide polymorphism (SNP) discovery. To access the genetic diversity of species like switchgrass, we developed a SNP discovery pipeline based on a network approach called the Universal Network-Enabled Analysis Kit (UNEAK). Complexities that hinder single nucleotide polymorphism discovery, such as repeats, paralogs, and sequencing errors, are easily resolved with UNEAK. Here, 1.2 million putative SNPs were discovered in a diverse collection of primarily upland, northern-adapted switchgrass populations. Further analysis of this data set revealed the fundamentally diploid nature of tetraploid switchgrass. Taking advantage of the high conservation of genome structure between switchgrass and foxtail millet (Setaria italica (L.) P. Beauv.), two parent-specific, synteny-based, ultra high-density linkage maps containing a total of 88,217 SNPs were constructed. Also, our results showed clear patterns of isolation-by-distance and isolation-by-ploidy in natural populations of switchgrass. Phylogenetic analysis supported a general south-to-north migration path of switchgrass. In addition, this analysis suggested that upland tetraploid arose from upland octoploid. All together, this study provides unparalleled insights into the diversity, genomic complexity, population structure, phylogeny, phylogeography, ploidy, and evolutionary dynamics of switchgrass.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Poster - 56: Preliminary comparison of FF- and FFF-VMAT for prostate plans with higher rectal dose

Purpose: A recent retrospective study found 53 patients previously treated to 78Gy/39 using flattened filtered (FF) 6X-VMAT at GRRCC had rectal DVH more than one standard deviation higher than the average. This study was to investigate if using 6FFFor10FFF beams could reduce these DVHs without compromising target coverage. Methods: Twenty patients’ plans were re-planed with 2-arc 6X-VMAT, 6FFF-VMAT and 10FFF-VMAT using the Eclipse TPS following departmental protocol. All plans had the same optimization and normalization, and were evaluated against the acceptance criteria from the QUANTEC and Emami. Statistical differences in the mean dose to OARs (D{sub m}) and PTV homogeneity index (HI) between energies were tested using the paired sample Wilcoxon signed rank statistical method (p<0.05). Beam delivery accuracy was checked on five patients using portal dosimetry (PD). Results: The PTV HI for the 10FFF shows no statistical difference from the 6X. All the OARs, except left femoral head with 6FFF, have significantly lower Dm using 6FFF and 10FFF .There is no difference in the maximum doses to rectum and bladder and are limited by the prescribed doses. Measurements show good agreements in the gamma evaluation (3%/3mm) for all energies. Conclusion: This preliminary study shows that doses to the OARs are reduced using 10FFF for the same target coverage. The plans using 6FFF result in lower doses to some OARs, and statistically different PTV HI. All plans showed very good agreement with measurements.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Palliative Prostate Artery Embolization for Prostate Cancer: A Case Series

Introduction: Prostate artery embolization (PAE) is recognized as a treatment for lower urinary tract symptoms (LUTS) in men with benign prostatic hyperplasia. LUTS and urinary retention are common in men with prostate cancer (PCa). The purpose of this study was to estimate the efficacy and safety of palliative PAE on LUTS or urinary retention in men with advanced PCa. Materials and methods: This prospective, single-center trial was conducted from March 2017 to November 2018. The trial protocol was registered online (ClinicalTrials.gov Identifier: NCT03104907). Only men with advanced PCa suffering from LUTS or urinary retention were included. The primary outcome was the ability to void without a catheter and International Prostate Symptom Score (IPSS) in non-catheter-dependent patients. The paired t test was used to analyze changes from baseline with 95% confidence intervals (CI). A p value < 0.05 was considered statistically significant. Results: Seventeen patients were assessed for eligibility, and 15 patients with a mean age of 73.8 years were enrolled. Four men did not complete follow-up: cancer-related death (n = 2), lost to follow-up (n = 1), and unsuccessful embolization due to severe atherosclerosis (n = 1). Bilateral embolization was achieved in ten cases, and urinary retention resolved in one of six patients. LUTS improved in the remaining (n = 5) patients by a mean 12.2-point reduction in IPSS (95% CI − 23.53; − 0.87). According to the CIRSE classification, two grade 1 and two grade 3 complications occurred. Conclusion: In this study, palliative PAE was safe and efficient for treatment for LUTS associated with PCa. Level of Evidence: Level 4, Case Series. Trial registration ClinicalTrials.gov Identifier: NCT03104907.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

SU-F-J-220: Micro-CT Based Quantification of Mouse Brain Vasculature: The Effects of Acquisition Technique and Contrast Material

Purpose: Cognitive impairment from radiation therapy to the brain may be linked to the loss of total blood volume in the brain. To account for brain injury, it is crucial to develop an understanding of blood volume loss as a result of radiation therapy. This study investigates µCT based quantification of mouse brain vasculature, focusing on the effect of acquisition technique and contrast material. Methods: Four mice were scanned on a µCT scanner (Siemens Inveon). The reconstructed voxel size was 18µm3 and all protocols were Hounsfield Unit (HU) calibrated. The mice were injected with 40mg of gold nanoparticles (MediLumine) or 100µl of Exitron 12000 (Miltenyi Biotec). Two acquisition techniques were also performed. A single kVp technique scanned the mouse once using an x-ray beam of 80kVp and segmentation was completed based on a threshold of HU values. The dual kVp technique scanned the mouse twice using 50kVp and 80kVp, this segmentation was based on the ratio of the HU value of the two kVps. After image reconstruction and segmentation, the brain blood volume was determined as a percentage of the total brain volume. Results: For the single kVp acquisition at 80kVp, the brain blood volume had an average of 3.5% for gold and 4.0% for Exitron 12000. Also at 80kVp, the contrast-noise ratio was significantly better for images acquired with the gold nanoparticles (2.0) than for those acquired with the Exitron 12000 (1.4). The dual kVp acquisition shows improved separation of skull from vasculature, but increased image noise. Conclusion: In summary, the effects of acquisition technique and contrast material for quantification of mouse brain vasculature showed that gold nanoparticles produced more consistent segmentation of brain vasculature than Exitron 12000. Also, dual kVp acquisition may improve the accuracy of brain vasculature quantification, although the effect of noise amplification warrants further study.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Estimation of breast percent density in raw and processed full field digital mammography images via adaptive fuzzy c-means clustering and support vector machine segmentation

Purpose: The amount of fibroglandular tissue content in the breast as estimated mammographically, commonly referred to as breast percent density (PD%), is one of the most significant risk factors for developing breast cancer. Approaches to quantify breast density commonly focus on either semiautomated methods or visual assessment, both of which are highly subjective. Furthermore, most studies published to date investigating computer-aided assessment of breast PD% have been performed using digitized screen-film mammograms, while digital mammography is increasingly replacing screen-film mammography in breast cancer screening protocols. Digital mammography imaging generates two types of images for analysis, raw (i.e., 'FOR PROCESSING') and vendor postprocessed (i.e., 'FOR PRESENTATION'), of which postprocessed images are commonly used in clinical practice. Development of an algorithm which effectively estimates breast PD% in both raw and postprocessed digital mammography images would be beneficial in terms of direct clinical application and retrospective analysis. Methods: This work proposes a new algorithm for fully automated quantification of breast PD% based on adaptive multiclass fuzzy c-means (FCM) clustering and support vector machine (SVM) classification, optimized for the imaging characteristics of both raw and processed digital mammography images as well as for individual patient and image characteristics. Our algorithm first delineates the breast region within the mammogram via an automated thresholding scheme to identify background air followed by a straight line Hough transform to extract the pectoral muscle region. The algorithm then applies adaptive FCM clustering based on an optimal number of clusters derived from image properties of the specific mammogram to subdivide the breast into regions of similar gray-level intensity. Finally, a SVM classifier is trained to identify which clusters within the breast tissue are likely fibroglandular, which are then aggregated into a final dense tissue segmentation that is used to compute breast PD%. Our method is validated on a group of 81 women for whom bilateral, mediolateral oblique, raw and processed screening digital mammograms were available, and agreement is assessed with both continuous and categorical density estimates made by a trained breast-imaging radiologist. Results: Strong association between algorithm-estimated and radiologist-provided breast PD% was detected for both raw (r= 0.82, p < 0.001) and processed (r= 0.85, p < 0.001) digital mammograms on a per-breast basis. Stronger agreement was found when overall breast density was assessed on a per-woman basis for both raw (r= 0.85, p < 0.001) and processed (0.89, p < 0.001) mammograms. Strong agreement between categorical density estimates was also seen (weighted Cohen's {kappa}{>=} 0.79). Repeated measures analysis of variance demonstrated no statistically significant differences between the PD% estimates (p > 0.1) due to either presentation of the image (raw vs processed) or method of PD% assessment (radiologist vs algorithm). Conclusions: The proposed fully automated algorithm was successful in estimating breast percent density from both raw and processed digital mammographic images. Accurate assessment of a woman's breast density is critical in order for the estimate to be incorporated into risk assessment models. These results show promise for the clinical application of the algorithm in quantifying breast density in a repeatable manner, both at time of imaging as well as in retrospective studies.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Rational designs to enable 10-min fast charging and long cycle life in lithium-ion batteries

A daunting challenge in the design of lithium ion batteries (LiBs) is enabling 10-min extreme fast charging (XFC) while achieving appreciable charge acceptance and cycle life. This desirable outcome requires both a comprehensive understanding of LiB operation and aging behavior at different length scales and careful optimization. Lithium plating has been a critical bottleneck because, at XFC rates, it consumes cyclable lithium causing distinct aging and safety concerns even in moderate-loading LiBs. Here, we propose combining multiple solutions, including materials-to-electrode design-to-charging protocols, that are intended to overcome limitations in lithium-ion transport in the electrolyte phase, thus enabling 10-min XFC in LiBs. Some implemented strategies include cathode chemistry, optimized carbon binder domain in the cathode, dual layer anode design, improved separator and advanced electrolyte. Further, innovative charging protocols in moderately loading (~3 mAh/cm 2 anode/2.7 mAh/cm 2 cathode) single-layer pouch cells are proposed, together with demonstrated 10-min XFC with higher charge acceptance between 87.3 and 92.1% (or 2–2.1 mAh/cm 2 ) for 600 cycles without lithium plating. This methodical study with well-defined cells shows promise in combining multiple solution strategies to enable 10-min XFC, charting a pathway to achieve XFC in higher-loading energy-optimized LiBs.

25 ENERGY STORAGE↗
DOE OSTI2011

An optimized colony forming assay for low-dose-radiation cell survival measurement

The aim of this study is to develop a simple and reliable method to quantify the cell survival of low-dose irradiations. Two crucial factors were considered, the same number of cells plated in each flask and an appropriate interval between cell plating and irradiation. For the former, we optimized cell harvest with trypsin, diluted cells in one container, and directly seeded cells on the bottom of flasks in a low density before irradiation. Reproducible plating efficiency was obtained. For the latter, we plated cells on the bottom of flasks and then monitored the processing of attachment, cell cycle variations, and the plating efficiency after exposure to 20 cGy of X-rays. The results showed that a period of 4.5 h to 7.5 h after plating was suitable for further treatment. In order to confirm the reliability and feasibility of our method, we also measured the survival curves of these M059K and M059J glioma cell lines by following the optimized protocol and obtained consistent results reported by others with cell sorting system. In conclusion, we successfully developed a reliable and simple way to measure the survival fractions of human cells exposed to low dose irradiation, which might be helpful for the studies on low-dose radiation biology.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2011

Calibration of the Gamma Knife Perfexion using TG-21 and the solid water Leksell dosimetry phantom

Purpose: To calibrate a Gamma Knife (GK) Perfexion using TG-21 with updated chamber-dependent values for modern microionization chambers in the new solid water Leksell dosimetry phantom. This work illustrates a calibration method using commercially available equipment, instruments, and an established dosimetry protocol that may be adopted at any GK center, thus reducing the interinstitutional variation in GK calibration. The calibration was verified by three third-party dosimetry checks. In addition, measurements of the relative output factors are presented and compared to available data and the new manufacturer-provided relative output factors yet to be released. Methods: An absolute dose calibration based on the TG-21 formalism, utilizing recently reported phantom material and chamber-dependent factors, was performed using a microionization chamber in a spherical solid water phantom. The result was compared to other calibration protocols based on TG-51. Independent verification of the machine output was conducted through M.D. Anderson Dosimetry Services (MDADS), using thermoluminescent dosimeters (TLDs) in an anthropomorphic head phantom; the Radiological Physics Center (RPC), using TLDs in the standard Elekta ABS plastic calibration phantom (gray phantom), included with the GK; and through a collaborative international calibration survey by the University of Pittsburgh Medical Center (UPMC) using alanine dosimeters, also in the gray phantom. The alanine dosimeters were read by the National Institute of Standards and Technology. Finally, Gafchromic EBT film was used to measure relative output factors and these factors were compared to values reported in the literature as well as new values announced for release by Elekta. The films were exposed in the solid water phantom using an included film insert accessory. Results: Compared to the TG-21 protocol in the solid water phantom, the modified and unmodified TG-51 calibrations resulted in dose rates which were 1.8% and 1.3% lower, respectively. Ratios of the doses measured by third parties to the dose reported showed excellent agreement. MDADS returned ratios of 1.00 and 0.98 for the two TLDs irradiated. The RPC returned a mean ratio of 0.98 of the dose reported and the UPMC alanine study returned a mean ratio of 1.008. Relative output factors were found to be 0.817{+-}0.009 and 0.897{+-}0.008 for the 4 and 8 mm collimators, respectively, which are in excellent agreement with revised Monte Carlo-derived relative output factors Elekta is expected to recommend with the next version of the GK treatment planning software (GAMMAPLAN version 10). Conclusions: The TG-21 dosimetry protocol, performed in a solid water phantom in conjunction with modern dosimeters and phantom material and chamber-dependent factors, can yield an accurate dose measurement in the unique GK treatment geometry. The technique described here can be easily adopted by institutions worldwide since all equipment and instruments used are commercially available, thus reducing the existing interinstitutional variation in GK calibration techniques. Relative output factor measurements made in this same solid water phantom were used to verify the relative output factors provided by Elekta and agreed excellently with output factors expected to be released in conjunction with GAMMAPLAN version 10.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Effects of a co-micronized composite containing palmitoylethanolamide and polydatin in an experimental model of benign prostatic hyperplasia

Palmitoylethanolamide (PEA), a fatty acid amide-signaling molecule has well-known anti-inflammatory and neuroprotective effects. Nevertheless, PEA does not possess the ability to prevent free radicals formation. Polydatin (PLD), a biological precursor of resveratrol, has antioxidant activity. A combination of PEA and PLD could, conceivably, have beneficial effects on oxidative stress produced by inflammatory processes. In the present study we investigated the effects of a co-micronized composite containing PEA and PLD (m(PEA/PLD)) in a model of testosterone-induced benign hyperplasia (BPH). BPH was provoked in rats by daily administration of testosterone propionate (3 mg/kg) for 14 days. This protocol leads to alterations in prostate morphology and increased levels of prostaglandin E2 and dihydrotestosterone as well as of 5α-reductase 1 and 5α-reductase 2 expression. Moreover, testosterone induced marked inflammation in terms of an increase in nuclear translocation of nuclear factor-κB p65 and consequently in IκB-α degradation as well as disregulation of inducible nitric oxide synthase, cyclooxygenase-2 and manganese superoxide dismutase expression and in the apoptosis pathway. Our results show, for the first time, that m(PEA/PLD) is capable of decreasing prostate weight and dihydrotestosterone production in BPH-induced rats. These effects were most likely correlated to the anti-inflammatory and apoptotic effects of m(PEA/PLD). Accordingly, these results support the view that m(PEA/PLD) should be further studied as a potent candidate for the management of BPH. - Highlights: • Chronic inflammation has emerged as a potential factor in the pathogenesis of BPH. • We evaluate the effects of m(PEA/PLD) in terms of impact on the inflammatory process and oxidative stress in BPH. • m(PEA/PLD) should be further explored as a valid candidate for the treatment of BPH.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Entanglement perspective on the quantum approximate optimization algorithm

Many quantum algorithms seek to output a specific bitstring solving the problem of interest—or a few if the solution is degenerate. It is the case for the quantum approximate optimization algorithm (QAOA) in the limit of large circuit depth, which aims to solve quadratic unconstrained binary optimization problems. Hence, the expected final state for these algorithms is either a product state or a low-entangled superposition involving a few bitstrings. What happens in between the initial N -qubit product state | 0 〉 ⊗ N and the final one regarding entanglement? Here, we consider the QAOA algorithm for solving the paradigmatic MaxCut problem on different types of graphs. We study the entanglement growth and spread resulting from randomized and optimized QAOA circuits and find that there is a volume-law entanglement barrier between the initial and final states. We also investigate the entanglement spectrum in connection with random matrix theory. In addition, we compare the entanglement production with a quantum annealing protocol aiming to solve the same MaxCut problems. Finally, we discuss the implications of our results for the simulation of QAOA circuits with tensor network-based methods relying on low-entanglement for efficiency, such as matrix product states.

Dupont, Maxime↗
DOE OSTI2024

Automated Immunoprecipitation Workflow for Comprehensive Acetylome Analysis

Immunoprecipitation is one of the most effective methods for enrichment of lysine-acetylated peptides for comprehensive acetylome analysis using mass spectrometry. Manual acetyl peptide enrichment method using non-conjugated antibodies and agarose beads has been developed and applied in various studies. However, it is time consuming, and can introduce contaminants and variability that leads to potential sample loss and decreased sensitivity and robustness of the analysis. Here we describe a fast, automated enrichment protocol that enables reproducible and comprehensive acetylome analysis using a magnetic bead-based immunoprecipitation reagent.

Lysine acetylation, Acetylome, Acetyl peptide enri↗
DOE OSTI2026

An International Round-Robin Study on Thermoelectric Module Testing and Development of Standard Power Generation Modules

An international round-robin study on thermoelectric power generation modules was conducted with nine participating laboratories. Two types of commercially available bismuth telluride modules, 30 mm × 30 mm and 40 mm × 40 mm, were used. A test protocol was followed with five temperature set points from 50°C to 150°C. Graphite sheets were used as thermal interface materials with test pressure at 100 psi (0.69 MPa). The results showed large lab-to-lab variations and the key source of uncertainty for module efficiency was identified as the heat flux measurement. In the meantime, significant uncertainty was also found in maximum electrical power (P max ) measurements. As a result of the round-robin, a “standard module” with 4 × 4 legs on a 20 mm × 20 mm platform was suggested. A skutterudite module and a half-Heusler module were produced with identical geometry and 4 mm × 4 mm × 8 mm legs. All transport properties to calculate the figure-of-merit, zT, were measured from ambient temperature to 500°C. Module performance was measured by two laboratories. Two finite-element-analysis (FEA)-based models were developed independently to simulate and predict the module performance. In conclusion, the standard modules eliminated significant test uncertainties and are aimed at assisting device design and achieving more accurate performance predictions.

Round-robin↗
DOE OSTI2019

Molybdenum isotope compositions of uranium ore concentrates by double spike MC-ICP-MS

The molybdenum (Mo) isotope composition of uranium ore concentrate (UOC) has been proposed as a nuclear forensic signature due to the ubiquitous presence of Mo in the nuclear fuel cycle and to the possibility that different UOC production pathways lead to characteristic Mo isotope fractionation. Furthermore, Mo forms a volatile hexafluoride which leads to the retainment of Mo in the nuclear fuel cycle through U enrichment and reactor operation processes. As a result, it is possible that the nuclear fuel cycle generates a rich array of Mo isotope signatures. The first step in interpreting Mo isotope signatures generated during the nuclear fuel cycle is to characterize the Mo isotope composition of starting materials. In this study, a suite of UOC samples were analyzed for their Mo isotope composition in order to constrain the range of Mo isotope compositions entering the front end of the nuclear fuel cycle. Analytical protocols were developed to purify Mo from a U rich matrix prior to Mo isotope analysis by double spike MC-ICP-MS. A >3‰ variation in the 98 Mo/ 95 Mo ratio was observed in the suite of UOC samples with δ 98 Mo ranging from -1.15 to +1.96‰ relative to the NIST 3134 Mo standard reference material. The δ98Mo range observed in the UOC samples is very similar to the δ 98 Mo range observed in crustal igneous rocks and Mo-bearing minerals, suggesting that Mo isotope variability in UOC is driven by variability in the parent U ores. However, Mo isotope fractionation during UOC production is evident with one of the UOC samples being isotopically heavy relative to its parent U ore by 0.75‰, suggesting that different UOC production processes also contribute to the total Mo isotope variability observed. Overall, it is expected that the Mo isotope signatures generated during enrichment and reactor process will be clearly discernible from those generated during UOC production.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Patterns of Failure After Concurrent Bevacizumab and Hypofractionated Stereotactic Radiation Therapy for Recurrent High-Grade Glioma

Purpose: Concurrent bevacizumab with hypofractionated stereotactic radiation therapy (HSRT) is safe and effective for the treatment of recurrent high-grade gliomas (HGG). The objective of this study was to characterize the patterns of failure after this treatment regimen. Methods and Materials: Twenty-four patients with recurrent enhancing HGG were previously treated on an institutional review board-approved protocol of concurrent bevacizumab and reirradiation. Patients received 30 Gy in 5 fractions to the recurrent tumor with HSRT. Brain magnetic resonance imaging (MRI) was performed every 2 cycles, and bevacizumab was continued until clinical or radiographic tumor progression according to the criteria of Macdonald et al. MRI at the time of progression was fused to the HSRT treatment plan, and the location of recurrence was classified on the basis of volume within the 95% isodose line. Outcomes based on patient characteristics, tumor grade, recurrence pattern, and best response to treatment were analyzed by the Kaplan-Meier method. Results: Twenty-two patients experienced either clinical or radiographic progression. Recurrent tumor was enhancing in 15 (71.4%) and nonenhancing in 6 (28.6%) patients. Eleven patients (52.4%) had recurrence within the radiation field, 5 patients (23.8%) had marginal recurrence, and 5 patients had recurrence outside the radiation field. Pattern of enhancement and location of failure did not correlate with overall survival or progression-free survival. Radiographic response was the only variable to significantly correlate with progression-free survival. Conclusions: Despite the promising initial response seen with the addition of HSRT to bevacizumab as salvage treatment for recurrent HGG, approximately half of patients ultimately still experience failure within the radiation field. The rate of local failure with the addition of HSRT seems to be lower than that seen with bevacizumab alone in the salvage setting. Our data underscore the radioresistance of HGG and the need for better salvage treatments.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Stereotactic Body Radiation Therapy for Spinal Metastases in the Postoperative Setting: A Secondary Analysis of Mature Phase 1-2 Trials

Purpose: To evaluate the outcomes in patients treated on prospective phase 1-2 protocols with postoperative stereotactic body radiation therapy (SBRT) and identify the associated prognostic variables. Methods and Materials: Sixty-six patients with 69 tumors were treated with SBRT on prospective phase 1-2 studies for spinal metastases between 2002 and 2010. All patients underwent SBRT after spine surgery, which included laminectomy, vertebrectomy, or a combination of these techniques. Renal cell carcinoma was the most common histology represented (n=35, 53%) followed by sarcomas (n=13, 20%). Thirty-one patients (47%) were treated with prior conventional radiation to the spine (median dose 30 Gy). Patients were followed up with spinal magnetic resonance imaging (MRI) studies to determine the treated tumor control (TC). Pain and other symptom data were collected prospectively to determine treatment response and toxicity. Results: The median follow-up time was 30 months (range, 1-145 months) for all patients and 75 months for living patients (range, 6-145 months). The actuarial 1-year rate of TC was 85%, adjacent vertebral body control was 85%, and overall survival (OS) was 74% (median 29 months). On multivariate competing-risks analysis, sarcoma histology (subhazard ratio [SHR] = 2.38, 95% confidence interval [CI] 1.05-5.6, P=.04) and larger preoperative tumor volumes (SHR=1.01, 95% CI 1.0-1.01, P=.006) were significantly associated with worse TC. Karnofsky performance status was the only significant predictor for OS on multivariate analysis. There were no differences in TC between patients treated with different surgical techniques or different preoperative or postoperative Bilsky grades. There were no grade 3 or higher neurologic toxicities. Conclusion: This study represents a large series of prospective data available on patients treated with SBRT in the postoperative setting. The combination of surgery with SBRT can offer patients with metastatic disease to the spine the chance of durable tumor control with minimal toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Oscillatory dynamics of an intravenous glucose tolerance test model with delay interval

We report that type 2 diabetes mellitus (T2DM) has become prevalent pandemic disease in view of the modern life style. Both diabetic population and health expenses grow rapidly according to American Diabetes Association. Detecting the potential onset of T2DM is an essential focal point in the research of diabetes mellitus. The intravenous glucose tolerance test (IVGTT) is an effective protocol to determine the insulin sensitivity, glucose effectiveness, and pancreatic β-cell functionality, through the analysis and parameter estimation of a proper differential equation model. Delay differential equations have been used to study the complex physiological phenomena including the glucose and insulin regulations. In this paper, we propose a novel approach to model the time delay in IVGTT modeling. This novel approach uses two parameters to simulate not only both discrete time delay and distributed time delay in the past interval, but also the time delay distributed in a past sub-interval. Normally, larger time delay, either a discrete or a distributed delay, will destabilize the system. However, we find that time delay over a sub-interval might not. We present analytically some basic model properties, which are desirable biologically and mathematically. We show that this relatively simple model provides good fit to fluctuating patient data sets and reveals some intriguing dynamics. Moreover, our numerical simulation results indicate that our model may remove the defect in well known Minimal Model, which often overestimates the glucose effectiveness index. Delay differential equations (DDEs) have been frequently used to study complex dynamics observed in nature. More recently, they are used to understand intriguing physiological phenomena such as those expressed by glucose and insulin interaction. We propose a simple set of delay differential equations to model an intravenous glucose tolerance test. This model uses two parameters to simulate not only both discrete time delay and distributed time delay in the past interval, but also the time delay distributed in a past sub-interval. We show that this relatively simple model provides good fit to fluctuating patient data sets and reveals some intriguing dynamics. Lastly and most importantly, our model may remove the defect in the well known Minimal Model (MM) which often overestimates the glucose effectiveness (GE) index.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Advancing quantum simulations of the nuclear shell model with Gray-code–based resource-efficient protocols

Background: Some of the computational limitations in solving the nuclear many-body problem could be overcome by utilizing quantum computers. The nuclear shell-model calculations providing deeper insights into the properties of atomic nuclei are one such case with high demand for resources, as the size of the Hilbert space grows exponentially with the number of particles involved. Quantum algorithms are being developed to overcome these challenges and advance such calculations. Purpose: To develop quantum circuits for the nuclear shell-model, leveraging the capabilities of noisy intermediate-scale quantum (NISQ) devices. Here, we aim to minimize resource requirements (specifically in terms of qubits and gates) and strive to reduce the impact of noise by employing relevant mitigation techniques. Methods: We achieve noise resilience by designing an optimized Ansatz for the variational quantum eigensolver (VQE) based on Givens rotations and incorporating qubit-ADAPT-VQE in combination with variational quantum deflation (VQD) to compute ground and excited states, incorporating the zero-noise extrapolation mitigation technique. Furthermore, the qubit requirements are significantly reduced by mapping the basis states to qubits using Gray-code encoding and generalizing transformations of fermionic operators to efficiently represent many-body states. Results: By employing the resource-efficient protocols, we achieve the ground and excited state energy levels of 38 Ar and 6 Li with better accuracy. These energy levels are presented for noiseless simulations, noisy conditions, and after applying noise mitigation techniques. Results are compared for Jordan-Wigner and Gray-code encoding using VQE, qubit-ADAPT-VQE, and VQD. Conclusions: Our work highlights the potential of resource-efficient protocols to leverage the full potential of NISQ devices in scaling the nuclear shell model calculations, offering a pathway toward more complex quantum simulations in nuclear physics. This approach establishes a framework for studying other nuclear systems with improved quantum resource efficiency, marking a significant advancement in applying quantum computing to realistic nuclear physics applications.

Physics - Nuclear physics and radiation physics↗
DOE OSTI2018

A Novel Interfacing Technique for Distributed Hybrid Simulations Combining EMT and Transient Stability Models

With steady increase of power electronic devices and nonlinear dynamic loads in large scale AC/DC systems, the traditional hybrid simulation method, which incorporates these components into a single EMT subsystem and hence causes great difficulty for network partitioning and significant deterioration in simulation efficiency. To resolve these issues, a novel distributed hybrid simulation method is proposed in this paper. The key to realize this method is a distinct interfacing technique, which includes: i) a new approach based on the two-level Schur complement to update the interfaces by taking full consideration of the couplings between different EMT subsystems; and ii) a combined interaction protocol to further improve the efficiency while guaranteeing the simulation accuracy. The advantages of the proposed method in terms of both efficiency and accuracy have been verified by using it for the simulation study of an AC/DC hybrid system including a two-terminal VSC-HVDC and nonlinear dynamic loads.

Distributed hybrid simulation↗