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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

Optimizing Screening for Preventable Blindness With Head-Mounted Visual Assessment Technology

Age-related macular degeneration (AMD) is a leading cause of blindness and is diagnosed as early-stage or late-stage. Early-stage AMD is usually asymptomatic and entails pigmentary changes of the retina (Ayoub & Patel, 2009). As the disorder progresses, there are atrophic or neovascular changes that distort vision, especially the central visual field (Ayoub & Patel, 2009). There are several genetic and non-genetic risk factors for AMD and no proven therapy to slow or reverse late-stage atrophic AMD, while anti-VEGF has effectively treated late-stage neovascular AMD. Several genes of interest have also been investigated thoroughly thus far in their connection to AMD and the CFH and ARMS2 genes have shown promise in understanding the genetic basis of the disorder (Awh et al., 2013). There are other epigenetic and environmental factors as well including smoking and low antioxidant levels (Cano et al., 2010). Ongoing investigations include antioxidant supplementation and a smoking cessation regimen to reverse early-stage AMD (Cano et al., 2010). Progress in treating AMD as a disorder across its varied stages requires newer therapeutics along with a more detailed understanding of the genetic and cellular pathways of pathophysiology is needed to better counter this prevalent disorder of the eye.

age-related macular degeneration↗
DOE OSTI2017

Spin-dependent constraints on blind spots for thermal singlino-higgsino dark matter with(out) light singlets

The LUX experiment has recently set very strong constraints on spin-independent interactions of WIMP with nuclei. These null results can be accommodated in NMSSM provided that the effective spin-independent coupling of the LSP to nucleons is suppressed. Here, we investigate thermal relic abundance of singlino-higgsino LSP in these so-called spin-independent blind spots and derive current constraints and prospects for direct detection of spin-dependent interactions of the LSP with nuclei providing strong constraints on parameter space. We show that if the Higgs boson is the only light scalar the new LUX constraints set a lower bound on the LSP mass of about 300 GeV except for a small range around the half of Z 0 boson masses where resonant annihilation via Z 0 exchange dominates. XENON1T will probe entire range of LSP masses except for a tiny Z 0 -resonant region that may be tested by the LZ experiment. These conclusions apply to general singlet-doublet dark matter annihilating dominantly to $t\bar{t}$. Presence of light singlet (pseudo)scalars generically relaxes the constraints because new LSP (resonant and non-resonant) annihilation channels become important. Even away from resonant regions, the lower limit on the LSP mass from LUX is relaxed to about 250 GeV while XENON1T may not be sensitive to the LSP masses above about 400 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Effect of liraglutide on myocardial glucose uptake and blood flow in stable chronic heart failure patients: A double-blind, randomized, placebo-controlled LIVE sub-study

Background: The glucagon-like peptide-1 analog liraglutide increases heart rate and may be associated with more cardiac events in chronic heart failure (CHF) patients. We studied whether this could be ascribed to effects on myocardial glucose uptake (MGU), myocardial blood flow (MBF) and MBF reserve (MFR). Methods and Results: CHF patients with left ventricular ejection fraction ≤45% and without type 2 diabetes were randomized to liraglutide (N = 18) 1.8 mg once daily or placebo (N = 18) for 24 weeks in a double-blinded design. Changes in MGU during an oral glucose tolerance test (OGTT) and changes in MBF and MFR from baseline to follow-up were measured quantitatively by {sup 18}F-FDG and {sup 15}O-H{sub 2}O positron emission tomography. Compared with placebo, liraglutide reduced weight (P = 0.03), HbA1c (P = 0.03) and the 2-hour glucose value during the OGTT (P = 0.004). Despite this, changes in MGU (P = 0.98), MBF (P = 0.76) and MFR (P = 0.89) from baseline to follow-up did not differ between groups. Furthermore, there was no association between the level of insulin resistance at baseline and changes in MGU in patients treated with liraglutide. Conclusion: Liraglutide did not affect MGU, MBF, or MFR in non-diabetic CHF patients. Any potential increase in cardiac events in these patients seems not to involve changes in MGU, MBF, or MFR. Trial Registration: Trial registry: http://www.ClinicalTrials.org . Identifier: NCT01472640. Url: https://clinicaltrials.gov/ct2/show/NCT01472640?term=NCT01472640&rank=1.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

On the origins of the linear no-threshold (LNT) dogma by means of untruths, artful dodges and blind faith

This paper is an historical assessment of how prominent radiation geneticists in the United States during the 1940s and 1950s successfully worked to build acceptance for the linear no-threshold (LNT) dose–response model in risk assessment, significantly impacting environmental, occupational and medical exposure standards and practices to the present time. Detailed documentation indicates that actions taken in support of this policy revolution were ideologically driven and deliberately and deceptively misleading; that scientific records were artfully misrepresented; and that people and organizations in positions of public trust failed to perform the duties expected of them. Key activities are described and the roles of specific individuals are documented. These actions culminated in a 1956 report by a Genetics Panel of the U.S. National Academy of Sciences (NAS) on Biological Effects of Atomic Radiation (BEAR). In this report the Genetics Panel recommended that a linear dose response model be adopted for the purpose of risk assessment, a recommendation that was rapidly and widely promulgated. The paper argues that current international cancer risk assessment policies are based on fraudulent actions of the U.S. NAS BEAR I Committee, Genetics Panel and on the uncritical, unquestioning and blind-faith acceptance by regulatory agencies and the scientific community. - Highlights: • The 1956 recommendation of the US NAS to use the LNT for risk assessment was adopted worldwide. • This recommendation is based on a falsification of the research record and represents scientific misconduct. • The record misrepresented the magnitude of panelist disagreement of genetic risk from radiation. • These actions enhanced public acceptance of their risk assessment policy recommendations.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Double-Blind, Placebo-Controlled Pilot Study of Processed Ultra Emu Oil Versus Placebo in the Prevention of Radiation Dermatitis

Purpose: The purpose of this single-institution pilot study was to evaluate the feasibility and safety of an oil-based skin agent, Ultra Emu Oil, on skin-related toxicity in patients undergoing radiation therapy to the breast or chest wall. Methods and Materials: Patients were randomized 2:1 in a double-blind fashion and were instructed to apply processed Ultra Emu Oil or placebo (cottonseed oil) twice daily during the course of radiation therapy. The oils were applied before the third fraction and continued for 6 weeks after completion of treatment. The primary endpoint was the area under the curve (AUC) of Skindex-16 scale scores over time. Secondary outcomes included maximum grade of radiation dermatitis using the Common Terminology Criteria (CTC) for Adverse Events (CTCAE 3.0), the Skin Toxicity Assessment Tool, quality of life (QOL) measured by Linear Analogue Self-Assessment, and a symptom experience diary (SED). Results: In all, 42 of 45 patients completed the study and were evaluable. The median times to peak rash, skin redness, peeling, and skin swelling were weeks 6, 6, 7, and 7, respectively as measured by the SED. The Skindex AUC scores tended to be lower in emu oil patients than in placebo patients (mean total AUC 7.2 vs 10.4, respectively). This trend was also seen in all the Skindex subdomains. The overall QOL was slightly better in the emu oil group but remained stable throughout the study for both arms. Peak CTC toxicity occurred at week 6. Patients using emu oil appeared slightly worse on maximum CTC grade, but the difference was not significant. Conclusions: This pilot study confirmed the safety of oil-based skin treatments during radiation therapy and suggests a trend for reduced skin toxicity for patients receiving emu oil. A larger study is needed to evaluate the efficacy of emu oil in reducing radiation dermatitis in patients receiving breast radiation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2022

Parotid Gland Stem Cell Sparing Radiation Therapy for Patients With Head and Neck Cancer: A Double-Blind Randomized Controlled Trial

Radiation therapy for head and neck cancer frequently leads to salivary gland damage and subsequent xerostomia. The radiation response of the parotid glands of rats, mice, and patients critically depends on dose to parotid gland stem cells, mainly located in the gland's main ducts (stem cell rich [SCR] region). Therefore, this double-blind randomized controlled trial aimed to test the hypothesis that parotid gland stem cell sparing radiation therapy preserves parotid gland function better than currently used whole parotid gland sparing radiation therapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Effects of Alcohol Administered with Flibanserin in Healthy Premenopausal Women: A Randomized, Double-Blind, Single-Dose Crossover Study

Abstract Introduction Flibanserin is approved in the United States and Canada for the treatment of hypoactive sexual desire disorder in premenopausal women. Aim The purpose of this trial was to evaluate the safety of concomitant administration of flibanserin with alcohol. Methods In this single-center, randomized, double-blind, single-dose, crossover study, participants were randomly assigned to 1 of 12 sequences to receive each of 7 treatments: flibanserin 100 mg or placebo with ethanol 0.2 g/kg, 0.4 g/kg, or 0.6 g/kg, or flibanserin 100 mg only. Treatments were administered using a worst-case approach that included morning dosing and consumption of alcohol within 10 minutes. Main Outcome Measure The primary end point was the proportion of participants who experienced dizziness, syncope, or hypotension. Safety end points included orthostatic vital signs. Results The study included 96 premenopausal women (mean age 31 ± 8 years). The incidence of dizziness for ethanol + flibanserin was 39.8% for ethanol 0.6 g/kg, 34.1% for 0.4 g/kg, and 27.4% for 0.2 g/kg compared with 31.1% for flibanserin without ethanol. Based on the available vital signs data, there was no effect of ethanol concentration on orthostatic blood pressure, vertigo, or hypotension; no instances of syncope were observed. The overall incidence of adverse events (AEs) was similar when flibanserin was administered alone (96.7%) or with ethanol (90.5–97.6%). Clinical Implications Consumption of the tested amounts of alcohol (0.2–0.6 g/kg) does not have an additive effect on the AE profile of flibanserin 100 mg in healthy premenopausal women. Strengths & Limitations Strengths include the study population (premenopausal women, as indicated for flibanserin) and range of ethanol doses. Limitations include the morning dosing of study medication, which is inconsistent with the bedtime dosing recommended for flibanserin, and the method of handling missing vital sign measurements. Conclusion Co-administration of flibanserin 100 mg with varying doses of ethanol resulted in few AEs of special interest, with no notable alcohol dose response. However, a significantly greater percentage of participants administered flibanserin with 0.6 g/kg and 0.4 g/kg of alcohol were characterized as “Participants in Whom Standing Blood Pressure Was Not Obtained” compared with participants administered flibanserin alone.

Simon, James A.↗
DOE OSTI2024

The Tribomechadynamics Research Challenge: Confronting blind predictions for the linear and nonlinear dynamics of a thin-walled jointed structure with measurement results

The present article summarizes the submissions to the Tribomechadynamics Research Challenge announced in 2021. The task was a blind prediction of the vibration behavior of a system comprising a thin plate clamped on two sides via bolted joints. Both geometric and frictional contact nonlinearities are expected to be relevant. Provided were the CAD models and technical drawings of all parts as well as assembly instructions. The main objective was to predict the frequency and damping ratio of the lowest-frequency mode as function of the amplitude. Many different prediction approaches were pursued, ranging from well-known methods to very recently developed ones. After the submission deadline, the system has been fabricated and tested. The aim of this article is to evaluate the current state of the art in modeling and vibration prediction, and to provide directions for future methodological advancements.

42 ENGINEERING↗
DOE OSTI2015

Oral prenylation inhibition with lonafarnib in chronic hepatitis D infection: a proof-of-concept randomised, double-blind, placebo-controlled phase 2A trial

Background: Therapies for chronic hepatitis delta virus (HDV) infection are unsatisfactory. Prenylation is essential for HDV and inhibition abrogates HDV production in experimental models. Here, in a proof-of-concept study, we aimed to assess the effect on HDV RNA levels, safety, and tolerability of the prenylation inhibitor lonafarnib in patients with chronic delta hepatitis. Methods: In this phase 2A double-blind, randomised, placebo-controlled study, patients aged 18 years or older with chronic HDV infection were randomly assigned (3:1 in group 1 and 2:1 in group 2) to receive lonafarnib 100 mg (group 1) or lonafarnib 200 mg (group 2) twice daily for 28 days with 6 months' follow-up. Participants were randomised by random-number tables blocked in groups of four without stratification. Both groups enrolled six treatment participants and two placebo participants. Group 1 placebo patients received open-label lonafarnib as group 2 participants. The primary therapeutic endpoint was a decrease in HDV RNA viral titre in serum and the primary safety endpoint was the ability to tolerate the drug at the prescribed dose for the full 4-week duration, defined as drug discontinuation due to intolerance or grade 3/4 adverse events. This trial is registered with ClinicalTrials.gov, number NCT01495585. Findings: Between Jan 19, 2012, and April 28, 2014, 14 patients were enrolled, of whom eight were assigned to group 1 and six were assigned to group 2. At day 28, compared with placebo, mean log HDV RNA declines from baseline were -0·73 log IU/mL in group 1 (95% CI 0·17–1·31; p=0·03) and -1·54 log IU/mL in group 2 (1·21–1·93; p<0·0001). Lonafarnib serum concentrations correlated with HDV RNA change (r 2 =0·78, p<0·0001). Model fits show that hepatitis B surface antigen (HBsAg) remained stable after a short pharmacological delay (0·75 days [SE 0·24]), lonafarnib effectiveness in blocking HDV production was greater in group 2 than in group 1 (0·952 [SE 0·06] vs 0·739 [0·05], p<0·001), and the HDV half-life was 1·62 days (0·07). There was no evidence of virological resistance. Adverse events were mainly mild to moderate with group 1 patients experiencing diarrhoea in three patients (50%) and nausea in two patients (33%) and in group 2 with all patients (100%) experiencing nausea, diarrhoea, abdominal bloating, and weight loss greater than 2 kg (mean of 4 kg). No treatment discontinuations occurred in any treatment groups. Interpretation: Treatment of chronic HDV with lonafarnib significantly reduces virus levels. The decline in virus levels significantly correlated with serum drug levels, providing further evidence for the efficacy of prenylation inhibition in chronic HDV.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Spectral restoration in high resolution electron energy loss spectroscopy based on iterative semi-blind Lucy-Richardson algorithm applied to rutile surfaces

A new spectral restoration algorithm of reflection electron energy loss spectra is proposed. It is based on the maximum likelihood principle as implemented in the iterative Lucy-Richardson approach. Resolution is enhanced and point spread function recovered in a semi-blind way by forcing cyclically the zero loss to converge towards a Dirac peak. Synthetic phonon spectra of TiO{sub 2} are used as a test bed to discuss resolution enhancement, convergence benefit, stability towards noise, and apparatus function recovery. Attention is focused on the interplay between spectral restoration and quasi-elastic broadening due to free carriers. A resolution enhancement by a factor up to 6 on the elastic peak width can be obtained on experimental spectra of TiO{sub 2}(110) and helps revealing mixed phonon/plasmon excitations.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

High-performance ultraviolet detection and visible-blind photodetector based on Cu{sub 2}O/ZnO nanorods with poly-(N-vinylcarbazole) intermediate layer

This study reports a high-performance hybrid ultraviolet (UV) photodetector with visible-blind sensitivity fabricated by inserting a poly-(N-vinylcarbazole) (PVK) intermediate layer between low-cost processed Cu{sub 2}O film and ZnO nanorods (NRs). The PVK layer acts as an electron-blocking/hole-transporting layer between the n-ZnO and p-Cu{sub 2}O films. The Cu{sub 2}O/PVK/ZnO NR photodetector exhibited a responsivity of 13.28 A/W at 360 nm, a high detectivity of 1.03 × 10{sup 13} Jones at a low bias of −0.1 V under a low UV light intensity of 24.9 μW/cm{sup 2}. The photo-to-dark current ratios of the photodetector with and without the PVK intermediate layer at a bias of −0.5 V are 1.34 × 10{sup 2} and 3.99, respectively. The UV-to-visible rejection ratios (R{sub 360 nm}/R{sub 450 nm}) are 350 and 1.735, respectively. Several features are demonstrated: (a) UV photo-generated holes at the ZnO NRs can effectively be transported through the PVK layer to the p-Cu{sub 2}O layer; (b) the insertion of a PVK buffer layer significantly minimizes the reverse-bias leakage current, which leads to a larger amplification of the photocurrent; and (c) the PVK buffer layer greatly improves the UV-to-visible responsivity ratio, allowing the device to achieve high UV detection sensitivity at a low bias voltage using a very low light intensity.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Blind test of density-functional-based methods on intermolecular interaction energies

In the past decade, a number of approaches have been developed to fix the failure of (semi)local density-functional theory (DFT) in describing intermolecular interactions. In this work, the performance of several such approaches with respect to highly accurate benchmarks is compared on a set of separation-dependent interaction energies for ten dimers. Since the benchmarks were unknown before the DFT-based results were collected, this comparison constitutes a blind test of these methods.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Note: The performance of new density functionals for a recent blind test of non-covalent interactions

Benchmark datasets of non-covalent interactions are essential for assessing the performance of density functionals and other quantum chemistry approaches. In a recent blind test, Taylor et al. benchmarked 14 methods on a new dataset consisting of 10 dimer potential energy curves calculated using coupled cluster with singles, doubles, and perturbative triples (CCSD(T)) at the complete basis set (CBS) limit (80 data points in total). Finally, the dataset is particularly interesting because compressed, near-equilibrium, and stretched regions of the potential energy surface are extensively sampled.

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

Beta gallium oxide (β-Ga 2 O 3 ) nanoelectromechanical transducer for dual-modality solar-blind ultraviolet light detection

Empowered by an ultrawide bandgap ( E g = 4.5–4.9 eV), beta gallium oxide (β-Ga 2 O 3 ) crystal is an ideal material for solar-blind ultraviolet (SBUV, λ < 280 nm) detection. Here, we report on the first demonstration of dual-modality SBUV light sensing integrated in the same device enabled by multi-physics coupling across photo-electrical and photo-thermo-mechanical domains. The specially designed suspended β-Ga 2 O 3 nanoelectromechanical systems (NEMS) transducer reveals dual-modality responses, with a photocurrent responsivity of 4 mA/W and a frequency shift responsivity of 250 Hz/nW, upon SBUV light exposure. An additional demonstration of a β-Ga 2 O 3 photo-field-effect transistor exhibits a boosted responsivity of 63 A/W. Analysis on the device suggests that reducing the thickness and length of the transducer could further improve the SBUV light sensing responsivities for both modalities. The demonstration could pave the way for future realization of SBUV detectors with dual modalities for enhanced detection fidelity, or respectively optimized for different sensing scenarios.

36 MATERIALS SCIENCE↗
DOE OSTI2020

High gain, large area, and solar blind avalanche photodiodes based on Al-rich AlGaN grown on AlN substrates

We demonstrate large area (25 000 μm2) Al-rich AlGaN-based avalanche photodiodes (APDs) grown on single crystal AlN substrates operating with differential (the difference in photocurrent and dark current) signal gain of 100 000 at 90 pW (<1 μW cm−2) illumination with very low dark currents <0.1 pA at room temperature under ambient light. The high gain in large area AlGaN APDs is attributed to a high breakdown voltage at 340 V, corresponding to very high breakdown fields ∼9 MV cm−1 as a consequence of low threading and screw dislocation densities < 103 cm−2. The maximum charge collection efficiency of 30% was determined at 255 nm, corresponding to the bandgap of Al0.65Ga0.35N, with a response of 0.06 A/W. No response was detected for λ > 280 nm, establishing solar blindness of the device.

Reddy, Pramod (ORCID:0000000285561178)↗
DOE OSTI2025

Requirements on the gain calibration for LiteBIRD polarisation data with blind component separation

The detection of primordial B modes of the cosmic microwave background (CMB) could provide information about the early stages of the Universe's evolution. The faintness of this signal requires exquisite calibration accuracy and control of instrumental systematic effects which otherwise could bias the measurements. In this work, we study the impact of an imperfect relative polarisation gain calibration on the recovered value of the tensor-to-scalar ratio r for the LiteBIRD experiment, through the application of the blind Needlet Internal Linear Combination (NILC) foreground-cleaning method. We derive requirements on the relative calibration accuracy of the overall polarisation gain (Δg ν ) for each LiteBIRD frequency channel. Our results show that minimum variance techniques, as NILC, are less sensitive to systematic gain calibration uncertainties compared to a parametric approach, if the latter is not equipped with a proper modelling of these instrumental effects. In this study, the most stringent requirements are found in the channels where the CMB signal is relatively brighter, with the tightest constraints at 166 GHz (Δg ν ≈ 0.16%). This differs from the outcome of an analogous analysis performed with a parametric method, where the tightest requirements are obtained for the foreground-dominated channels. Gain calibration uncertainties, corresponding to the derived requirements, are then simultaneously propagated into all frequency channels. By doing so, we find that the overall impact on estimated r is lower than the total gain systematic budget for LiteBIRD approximately by a factor 5, due to the correlations of the impacts of gain calibration uncertainties in different frequency channels. In order to decouple the systematic effect from the specific choice of the model, we derive the requirements assuming constant spectral parameters for the foreground emission. To assess the robustness of the obtained results against more realistic scenarios, we repeat the analysis assuming sky models of intermediate and high complexity. In these further cases, we adopt an optimised NILC pipeline, called the Multi-Clustering NILC (MC-NILC). We find that the impact of gain calibration uncertainties on r is lower than the LiteBIRD gain systematics budget for the intermediate-complexity sky model. For the high-complexity case, instead, it would be necessary to tighten the requirements by a factor 1.8.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Lensing without borders – I. A blind comparison of the amplitude of galaxy–galaxy lensing between independent imaging surveys

ABSTRACT Lensing without borders is a cross-survey collaboration created to assess the consistency of galaxy–galaxy lensing signals (ΔΣ) across different data sets and to carry out end-to-end tests of systematic errors. We perform a blind comparison of the amplitude of ΔΣ using lens samples from BOSS and six independent lensing surveys. We find good agreement between empirically estimated and reported systematic errors which agree to better than 2.3σ in four lens bins and three radial ranges. For lenses with zL > 0.43 and considering statistical errors, we detect a 3–4σ correlation between lensing amplitude and survey depth. This correlation could arise from the increasing impact at higher redshift of unrecognized galaxy blends on shear calibration and imperfections in photometric redshift calibration. At zL > 0.54, amplitudes may additionally correlate with foreground stellar density. The amplitude of these trends is within survey-defined systematic error budgets that are designed to include known shear and redshift calibration uncertainty. Using a fully empirical and conservative method, we do not find evidence for large unknown systematics. Systematic errors greater than 15 per cent (25 per cent) ruled out in three lens bins at 68 per cent (95 per cent) confidence at z < 0.54. Differences with respect to predictions based on clustering are observed to be at the 20–30 per cent level. Our results therefore suggest that lensing systematics alone are unlikely to fully explain the ‘lensing is low’ effect at z < 0.54. This analysis demonstrates the power of cross-survey comparisons and provides a promising path for identifying and reducing systematics in future lensing analyses.

79 ASTRONOMY AND ASTROPHYSICS↗