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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 883 records · Page 49
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

In comparison with other abdominal imaging modalities, which radiologists interpret abdominal MRI?

Purpose: To assess subspecialty mix and case volumes of general and abdominal subspecialty radiologists interpreting abdominal MRI. Methods: The 2016 CMS Physician/Supplier Procedure Summary Master File was used to obtain billed counts of radiologist-interpreted abdominal fluoroscopy, US, CT, and MRI examinations. The CMS Physician and Other Supplier Public Use File was used to assess the subspecialty mix and case volume of the radiologists interpreting those examinations. Results: The fraction of all abdominal imaging examinations interpreted by generalists and abdominal subspecialty radiologists was 70.7% and 16.5% for fluoroscopy; 68.7% and 21.0% for US; 71.4% and 19.2% for CT; and 41.9% and 52.5% for MRI. In 2016, the fraction of general and abdominal radiologists interpreting > 50 fluoroscopy examinations on Medicare fee-for-service beneficiaries was 15.1% and 16.2%. For > 50 US examinations, the fraction was 61.5% and 60.5%; for > 50 CT examinations, 91.2% and 79.6%; and for > 50 MRI examinations, 4.0% and 28.5%. The fraction of abdominal imaging examinations interpreted overall by low-volume providers (those interpreting ≤ 50 examinations in 2016) was 59.5% for fluoroscopy, 17.5% for US, 6.3% for CT, and 50.6% for MRI. Conclusion: Nationally, most abdominal fluoroscopy, US, and CT examinations are interpreted by general radiologists, who have similar annual volumes of these examinations as abdominal subspecialty radiologists. In contrast, most abdominal MRI examinations are interpreted by abdominal subspecialty radiologists, who attain considerably higher volumes. These findings have implications for workforce planning and abdominal imaging fellowship design to ensure their graduates are optimally prepared to contribute to their future practices.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Diagnostic accuracy of acoustic radiation force impulse elastography (ARFI) in comparison to other non-invasive modalities in staging of liver fibrosis in chronic HCV patients: single-center experience

Purpose: To evaluate the reliability of ARFI elastography for liver fibrosis staging and compare it to other non-invasive assessment of hepatic fibrosis (FIB-4 and APRI) in chronic HCV (CHC) patients. Methods: A single-center, prospective study included 2103 CHC patients. Liver stiffness (LS) was evaluated by TE and ARFI elastography. FIB-4 and APRI were calculated. The area under the receiver-operating characteristic curve (AUROCs) was used to assess the diagnostic performance of ARFI elastography for staging of liver fibrosis using TE as a reference standard. Results: The best cut off values of ARFI elastography for diagnosis of ≥ F2, ≥ F3and F4 were 1.36 m/s, 1.45 m/s, and 1.7 m/s with AUROCs of 0.89, 0.94 and 0.95, respectively. ARFI elastography cut offs are lower in patients with normal ALT level compared to those with ALT level (1.1–< 3 ULN) and those with ALT level ≥ 3ULN (1.35 m/s vs 1.39 m/s vs 1.54 for F ≥ 2, 1.44 m/s vs 1.58 m/s vs 1.6 m/s for F3, 1.69 m/s, 1.84 m/s, 1.86 m/s for F4). FIB-4 (0.82–0.86) and APRI (0.78–0.82) yielded lower AUC in prediction of significant fibrosis and cirrhosis than ARFI elastography (0.89–0.95). Conclusion: ARFI elastography is a reliable method for non-invasive staging of liver fibrosis in CHC patients when compared to TE with a good diagnostic performance comparable to FIB-4 and APRI scores for the prediction of significant fibrosis and cirrhosis.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Endovascular Therapy as a Primary Revascularization Modality in Acute Mesenteric Ischemia

PurposeTo evaluate endovascular therapy (EVT) as the primary revascularization method for acute mesenteric ischemia (AMI).MethodsA retrospective review was performed on all consecutive patients treated for AMI during a 5-year period (January 2009 to December 2013). EVT was attempted in all patients referred for emergent revascularization. Surgical revascularization was performed selectively after failure of EVT. Patient characteristics, clinical presentation, and outcomes were studied. Failures and complications of EVT were recorded.ResultsFifty patients, aged 79 ± 9 years (mean ± SD), out of 66 consecutive patients with AMI secondary to embolic or thrombotic obstruction of the superior mesenteric artery were referred for revascularization. The etiology of AMI was embolism in 18 (36 %) and thrombosis in 32 (64 %) patients. EVT was technically successful in 44 (88 %) patients. Mortality after successful or failed EVT was 32 %. The rates of emergency laparotomy, bowel resection, and EVT-related complication were 40, 34, and 10 %, respectively. Three out of six patients with failure of EVT were treated with surgical bypass. EVT failure did not significantly affect survival.ConclusionsEVT is feasible in most cases of AMI, with favorable patient outcome and acceptable complication rate.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Rhabdomyosarcoma in adults: analysis of treatment modalities in a prospective single-center series

Rhabdomyosarcoma (RMS) is rare in adults and it is generally characterized by poor outcome. In a previous retrospective study, we demonstrated a better prognosis in adults treated with multimodality approach resembling pediatric protocols. Thereafter, we developed specific recommendations based on the principles adopted in pediatric oncology. The present analysis reports the results in a subsequent prospective series. The study included 95 consecutive patients (age 18–77 years) treated from 2002 to 2015 for embryonal and alveolar RMS. As in the previous series, patients were stratified by the appropriateness of their treatment according to therapeutic guidelines for childhood RMS. The 5-year event-free survival (EFS) and overall survival (OS) rates were 33.6% and 40.3%, respectively. The 5-year EFS was 40.8% for patients with the highest treatment score, and 15% for those with lower score, while OS was 44.4% and 24.5%, respectively. The developing of specific recommendations enabled an increase in the number of patients treated with intensive multimodal treatment resembling pediatric strategy (69.7% vs. 39.1% in the retrospective series). This study reinforced the idea that adherence to the principles of pediatric protocols, improves adult RMS outcomes. However, treating adults with pediatric-type strategy is not enough to achieve the results obtained in children. Issues in compliance and a more aggressive biology of adult RMS might have a role in the different outcome according to age. Improving the collaboration between pediatric and adult oncologists in promoting specific clinical and biological research is crucial to improve the outcome for this patient population.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2025

Multi-modal characterization of the B2 phase in the Ta-Re binary system

The energy and transportation industries demand materials that retain their mechanical property at high temperatures. Refractory complex concentrated alloys (RCCAs) with a BCC + B2 microstructure offer a potential solution, where maintaining the high temperature mechanical properties can be achieved by precipitation strengthening. This depends on the B2 phase in RCCAs being thermodynamically stable with a high solvus temperature. Recently, we predicted the high temperature stability of the B2 structure in the Ta-Re binary system, using density functional theory. Here, in this study, we provide experimental evidence for the existence of this phase for the first time, using a Ta 65 Re 35 alloy. Despite Ta-Re binary phase diagrams predicting a single-phase BCC microstructure for Ta 65 Re 35 , we show that a high Z nanoscale secondary phase appears after heat treatment at 1550 °C and 1100 °C. Scanning transmission electron microscopy (STEM) revealed that this phase has a cubic structure and is equiatomic TaRe though B2 superlattice reflections were absent in fast Fourier transforms (FFT) and diffraction patterns (DPs). DP simulations indicate that the B2 TaRe superlattice reflections are up to two orders of magnitude weaker than their fundamental reflections, making their detection challenging via electron microscopy. Neutron diffraction confirmed the second phase had a B2 structure. This study identified a previously unobserved high temperature stable B2 phase in the Ta-Re system, enabling the development of new high temperature BCC + B2 RCCAs.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Multi-modal characterization and simulation of human epileptic circuitry

Temporal lobe epilepsy is the fourth most common neurological disorder, with about 40% of patients not responding to pharmacological treatment. Increased cellular loss is linked to disease severity and pathological phenotypes such as heightened seizure propensity. While the hippocampus is the target of therapeutic interventions, the impact of the disease at the cellular level remains unclear. Here, we show that hippocampal granule cells change with disease progression as measured in living, resected hippocampal tissue excised from patients with epilepsy. We show that granule cells increase excitability and shorten response latency while also enlarging in cellular volume and spine density. Single-nucleus RNA sequencing combined with simulations ascribes the changes to three conductances: BK, Cav2.2, and Kir2.1. In a network model, we show that these changes related to disease progression bring the circuit into a more excitable state, while reversing them produces a less excitable, “early-disease-like” state.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Wide-Area Measurement-Based Modal Decoupling for Power System Oscillation Damping

Inter-area oscillation modes usually fall within the same frequency range of 0.1 to 1.0 Hz; thus, power oscillation damping (POD) control methods should avoid unnecessary excitation of weakly damped modes. This paper presents a decoupled control strategy to damp inter-area oscillations in the power grid. Pure oscillation mode signals are extracted from wide-area measurements and used as feedback input for POD actuators such as power system stabilizers or high-voltage direct current transmission. The decoupled control strategy is able to increase the damping of the concerned oscillation modes without deteriorating others. This proposed strategy could be implemented independently, or serve as a complement and work along with conventional POD controllers to damp concerned inter-area modes. The proposed method has been tested on a modied MinniWECC system. Extensive results indicate that inter-area oscillations can be successfully and precisely damped using the proposed decoupled strategy.

Fan, Rui↗