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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Flat gain C + L band using optical amplifiers for 200 × 14 Gbps DWDM system

This paper has shown the analysis of 200 channels dense wavelength division multiplexing (DWDM) system with the data rate of 14 Gbps for attaining the flat gain for the channel spectrum from 1520 to 1640 nm. Analysis has also extended with the power amplification of erbium–ytterbium co-doped optical amplifier (EYBCDOWA) and Raman optical amplifier for the transmission distance of 120 km to mitigate the effect of crosstalk and bit error rate (BER). Final analysis has also recommended that this proposed system is capable to deliver the flat gain of 19.5 dB with minor variation of 0.95 dB to maintain the acceptable dense communication for long distance.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Tunable terahertz structure based on graphene hyperbolic metamaterials

Photoexcited graphene can behave as the gain medium aiming to come up with the coherent radiation at low THz spectral region. However, its response is very weak because of its atomic dimensions. Herein, a different design aiming to obtain effective tunable THz amplifiers, having small dimensions and lasers with broadband operation based on active THz hyperbolic metamaterials (HMM) is demonstrated. HMMs are considered by employing multiple stacked photoexcited graphene sheets divided by dielectric spacers. Herein, we study and characterize the hyperbolic THz regime of the studied atomic active HMM. A broadband slow-wave propagation regime takes place if the graphene-based HMM system is periodically patterned. This occurs due to the hyperbolic dispersion. Doing so, reconfigurable amplification of THz waves in a broad-spectrum region is attained. This might be engineered by tuning the quasi-Fermi level of graphene. Moreover, the mechanisms leading to the increase of the frequency region of bound surface wave have been proposed in the frame of the current study.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Imaginary resistor based Parity-Time symmetry electronics dimers

An approach of fabricating Parity-Time symmetry electronic dimers circuits is demonstrated using an imaginary resistor Z whose impedance is frequency independent. Remarkably, the dynamic rate equations of the coupled oscillators so-called ZRC dimers, uniquely consist of first order partial differential equations which result in a 2 ×2 effective Hamiltonians commuting with the joint Parity-Time (PT) operator. The method helps in describing two groups of PT symmetry electronics. The first group has an eigenspectrum that displays a single spontaneous PT transition or a thresholdless (THL) PT transition. The second group is a PT transitionless normal mode spectrum with essentially negative values of capacitors. The dynamics indicate that the system exhibits high frequencies propagation when operation is done before the thresholdless point is reached. The transitionless regime indicates an equilibrium point in the coupling for which the system turns to be conservative regardless the gain/loss values, and beyond which the gain/loss remarkably decays/amplifies wave. In addition, we observe a value of gain/loss above which there is a limitation of signal amplification.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

Enhancing scalability and accuracy of quantum poisson solver

The Poisson equation has many applications across the broad areas of science and engineering. Most quantum algorithms for the Poisson solver presented so far either suffer from lack of accuracy and/or are limited to very small sizes of the problem and thus have no practical usage. In this regard, our previous work showed a proof-of-concept demonstration in advancing quantum Poisson solver algorithm and validated preliminary results for a simple case of 3 x 3 problem. In this work, we delve into comprehensive research details, presenting the results on up to 15 x 15 problems that include step-by-step improvements in Poisson equation solutions, scaling performance, and experimental exploration. In particular, we demonstrate the implementation of eigenvalue amplification by a factor of up to 2 8 , achieving a significant improvement in the accuracy of our quantum Poisson solver and comparing that to the exact solution. Additionally, we present success probability results, highlighting the reliability of our quantum Poisson solver. Moreover, we explore the scaling performance of our algorithm against the circuit depth and width, demonstrating how our approach scales with larger problem sizes and thus further solidifies the practicality of easy adaptation of this algorithm in real-world applications. We also discuss a multilevel strategy for how this algorithm might be further improved to explore much larger problems with greater performance. Finally, through our experiments on the IBM quantum hardware, we conclude that though overall results on the existing NISQ hardware are dominated by the error in the CNOT gates, this work opens a path to realizing a multidimensional Poisson solver on near-term quantum hardware.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2019

Effectiveness of a genetic test panel designed for gynecological cancer: an exploratory study

To increase diagnostic efficiency and cost-effectiveness, we performed an exploratory genetic test using a newly designed panel containing 28 actionable and druggable genes, alterations in which are frequently reported in gynecological cancers (TANRE-G, Targeted variants ANalysis RElated to Gynecological cancers). Samples consisted of the formalin-fixed, paraffin-embedded tissue of endometrial (4 cases), cervical (3 cases), and ovarian (4 cases) carcinomas. The sequencing procedure was performed using Ion PGM in our institute with related sequencing kits, and data were analyzed using ClinVar. The present system achieved more than 2500 reads in all tumor samples, and enabled a copy number variation analysis. Results showed that actionable and druggable mutations were detected in 82% (9/11) and 64% (7/11) of cases, respectively, which was similar to other commercially available genetic tests. The amplification of MYC and KRAS was also detected. The analysis cost for each sample was JPY 94,000 (USD 850). These results demonstrate the potential of the TANRE-G panel as an effective tool for examining genetic alterations in gynecological cancers.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

SOX4 is activated by C-MYC in prostate cancer

Although MYC proto-oncogene (C-MYC) amplification has been consistently reported to be a potential marker for prostate cancer (PCa) progression and prognosis, the clinicopathological and prognostic significance of C-MYC protein expression remains controversial. Overexpression of SOX4 has been shown to play important roles in multiple cancers including PCa. However, the link between these two critical genetic aberrations is unclear. In the current study, we showed that C-MYC was overexpressed in 16.2% (17/105) of Chinese patients with localized PCa. Overexpression of C-MYC was significantly associated with high Gleason scores (P = 0.012) and high Ki67 labeling index (P = 0.005). C-MYC overexpression was correlated with cancer-related mortality and suggested to be an unfavorable prognostic factor in Chinese PCa patients (P = 0.018). Overexpression of C-MYC is associated with SOX4 overexpression in PCa tissues. Notably, SOX4 is a direct target gene of C-MYC; C-MYC activates SOX4 expression via binding to its promoter. In addition, Co-IP analysis demonstrated a physical interaction between C-MYC and SOX4 protein in PCa cells. Clinically, C-MYC+/SOX4+ characterized poor prognosis in a subset of PCa patients. In total, C-MYC overexpression may contribute to PCa progression by activating SOX4. Our findings highlight an important role of C-MYC/SOX4 in PCa progression in a subset of PCa patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2024

Reassessing the Climate Change Narrative

Abstract We note that the atmosphere has distinct tropical and extratropical regimes. The tropical regime is significantly dependent on the greenhouse effect and is characterized by temperatures that are largely horizontally homogenized. The extratropical regime is dominated by large scale unstable convective eddies that transport heat between the tropics and the poles (leaving the poles warmer than they otherwise would be) and serve to determine the temperature difference between the tropics and the poles. Changes in tropical temperature and in the tropics-to-pole temperature difference both contribute to changes in global mean temperature. It turns out that changes in global mean temperature associated with major climate change (i.e., the last glacial maximum and the warm period of the Eocene about 50 million years ago) were associated primarily with changes in the tropics-to-pole temperature differences. By contrast, changes in global mean temperature over the past 150 years or so are almost entirely associated with changes in tropical temperature. Thus, there is no intrinsic amplification associated with a change in the tropics-to-pole temperature difference. However, model simulations of climate behave differently from both observations and from each other. In particular, they all show more significant contributions for the tropics-to-pole temperature difference – sometimes much more significant. They also show excessive tropical warming.

Meteorology & Atmospheric Sciences↗
DOE OSTI2018

Controllable generation of photons and phonons in a coupled Bose–Einstein condensate-optomechanical cavity via the parametric dynamical Casimir effect

We theoretically propose and investigate a feasible experimental scheme for the realization of the dynamical Casimir effect (DCE) in a hybrid optomechanical cavity with a moving end mirror containing an interacting cigar-shaped Bose–Einstein condensate (BEC). We show that in the red-detuned regime of cavity optomechanics together with the weak optomechanical coupling limit by coherent modulation of the s-wave scattering frequency of the BEC and the mechanical spring coefficient of the mechanical oscillator (MO), the mechanical and atomic quantum vacuum fluctuations are parametrically amplified, which consequently lead to the generation of the mechanical/Bogoliubov-type Casimir phonons. Interestingly, in the coherent regime corresponding to the case of largely different optomechanical coupling strengths of the cavity field to the BEC and the MO, or equivalently largely different cooperativities, one can generate a large number of Casimir photons due to the amplification of the intracavity vacuum fluctuations induced by the time modulations of the BEC and the MO. The number of generated Casimir particles are externally controllable by the cooperativities, and the modulation amplitudes of the atomic collisions rate and the mechanical spring coefficient.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

MiR-455-3p suppresses renal fibrosis through repression of ROCK2 expression in diabetic nephropathy

Highlights: • Downregulation of miR-455-3p expression in DN. • ROCK2 as a target of miR-455-3p. • Re-introduction of ROCK2 attenuated the effect of miR-455-3p on cell proliferation, ECM accumulation and EMT in vitro. • Reductions in proinflammatory levels and renal fibrosis by miR-455-3p usages, in vivo. Emerging evidence has shown that microRNAs (miRNAs) play a mediatory role in the pathogenesis of diabetic nephropathy (DN), but the function of the involved miRNAs is still incomplete. Here, we found that miR-455-3p was down-regulated in the human mesangial cells (HMC) and human proximal tubule epithelial cells (HK-2) stimulated with high glucose (HG) or transforming growth factor beta 1 (TGF-β1). Rho-associated coiled coil-containing protein kinase 2 (ROCK2) was identified as a directed target of miR-455-3p. Overexpression of ROCK2 significantly attenuated the inhibitory effects of miR-455-3p on cell proliferation, extracellular matrix (ECM) synthesis and epithelial-mesenchymal transition (EMT) in HG-treated cells. Furthermore, the DN model was prepared by using high-fat feeding combined with Streptozotocin (STZ) induced rats, and the DN group was treated by injecting miR-455-3p agomir. The results of periodic acid-Schiff (PAS) and Masson staining showed that miR-455-3p overexpression improved the pathological changes of glomerular hypertrophy, mesangial amplification, and renal fibrosis. Additionally, miR-455-3p overexpression decreased ROCK2, proliferating cell nuclear antigen (PCNA) and Collagen I levels, and also reduced inflammatory cytokines TNF-α, MCP-1 and IL-1β levels in vivo. Altogether, these results suggest that miR-455-3p plays an essential role in the treatment of renal fibrosis through repressing ROCK2 expression; and miR-455-3p might be an effective therapy for DN.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

DNA copy number gain-mediated lncRNA LINC01061 upregulation predicts poor prognosis and promotes papillary thyroid cancer progression

Several DNA copy number amplifications (CNAs) have been reported in papillary thyroid cancer (PTC). However, the functional role of CNAs in PTC remains very unclear. And whether there is a correlation between long noncoding RNA (lncRNA) and CNA requires to be explored. Here, we identified a novel lncRNA LINC01061. The genomic copy number of LINC01061 is amplified, which leads to its elevated expression level in PTC tissues. Moreover, increased level of LINC01061 was correlated with aggressive clinicopathological characteristics. Functional study indicated that LINC01061 silence significantly inhibited the proliferation, cell-cycle and invasion of PTC cells in vitro and tumor growth in vivo. Mechanistically, we showed that LINC01061 interacted with miR-4316 to promote E2F6 expression. The expression of miR-4316 was downregulated in PTC tissues while that of E2F6 was upregulated. Through rescue assay, we demonstrated that LINC01061 promoted PTC cell proliferation, cell-cycle progression and invasion by regulating miR-4316/E2F6 signaling pathway. In conclusion, our research indicated that LINC01061 might be a target for PTC therapy.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Anti-EGFR antibody cetuximab is secreted by oral squamous cell carcinoma and alters EGF-driven mesenchymal transition

Genetic amplification, overexpression, and increased signaling from the epidermal growth factor receptor (EGFR) are often found in oral squamous cell carcinoma (OSCC) and thus EGFR is frequently targeted molecularly by the therapeutic antibody cetuximab. We assessed effects of cetuximab in control of EGF-driven malignant traits of OSCC cells. EGF stimulation promoted progression level of mesenchymal traits in OSCC cells, which were attenuated by cetuximab but incompletely. We pursued a potential mechanism underlying such incomplete attenuation of OSCC malignant traits. Cetuximab promoted secretion of EGFR-EVs by OSCC cells and failed to inhibit EGF-driven secretion of EGFR-EVs. Cetuximab was also found to be robustly secreted with the EGFR-EVs by the OSCC cells. Thus, EGF promotes the level of mesenchymal traits of OSCC cells and secretion of EGFR-EVs, which involve cetuximab resistance.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Tissue-specific variation in 5-terminal exons of mouse Anoctamin 1 transcript induces N-terminal variation of its protein via alternative translational start sites

Anoctamin 1 (encoded by the Ano1 gene) is a Ca{sup 2+}-activated Cl{sup −} channel critical to many physiological functions. It has been speculated that Ano1 expression is regulated in a tissue-dependent manner via alternative promoters. However, variation in the 5-end sequence of mouse Ano1 (mAno1) and its tissue-dependent regulation are poorly understood. We identified a novel 5-terminal exon (designated exon 1a) of mAno1 instead of the known 5-terminal exon (exon 0) using 5-rapid amplification of cDNA ends (RACE) analysis. Unexpectedly, the novel 5-end variant mAno1{sub Ex1a} was abundantly expressed in many tissues including the salivary and mammary glands, rectum, lung, trachea and prostate. In contrast, the known variant mAno1{sub Ex0} predominated only in male reproductive tissues such as the epididymis and testis. In a heterologous expression system, mAno1{sub Ex0} encoded a longer protein than mAno1{sub Ex1a}, and this long isoform was abolished by a mutation in the exon 0 start codon. Moreover, the mAno1{sub Ex0}-specific N-terminal sequence was immunohistochemically detected in epididymis but not in salivary gland. Our data suggest that mAno1 expression is regulated via alternative promoters, and its transcriptional variation results in variation of the N-terminal sequence of the Ano1 protein due to the alternative translation initiation sites. These tissue-specific variations might contribute to the regulation of mAno1 expression and activity according to the physiological function of each tissue.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Sterol regulatory element binding protein-1: Molecular cloning, tissue distribution and gene expression level in response to nutritional regulation in mud crab, Scylla paramamosain

Highlights: • The complete SREBP-1 cDNA sequence was cloned from the hepatopancreas of mud crab based on the RACE technology. • Tissue distribution analysis revealed that SREBP-1 transcripts were widely distributed in various organs, with higher mRNA levels in the eyestalk and cranial ganglia. • The expression level of SREBP-1 mRNA were up-regulated in proportion to the replacement of dietary fish oil with soybean oil. In the present study, SREBP-1 cDNA was cloned from the hepatopancreas of mud crab (Scylla paramamosain) and characterized by performing rapid-amplification of cDNA ends. The 3361bp long full-length cDNA encodes a polypeptide with 1039 amino acids. Tissue distribution analysis revealed that SREBP-1 transcripts were widely distributed in various organs, with higher mRNA levels in the eyestalk and cranial ganglia. Further, expression level of SREBP-1 mRNA were up-regulated in proportion to the replacement of dietary fish oil (FO) with soybean oil (SO). These results may contribute to better understanding of the long-chain polyunsaturated fatty acids (LC-PUFA) biosynthetic pathway and regulation mechanism in mud crab.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Effects of molecular crowding on a bimolecular group I ribozyme and its derivative that self-assembles to form ribozyme oligomers

Highlights: • PEG rescued mutations in the bimolecular group I ribozyme more effectively than those in the oligomeric form. In the RNA world, enrichment of self-replicating RNAs would have been beneficial to their survival, amplification, and evolution. Self-assembly of RNAs may be a strategy by which they enrich themselves. We examined the effects of molecular crowding on the activity of a bimolecular group I ribozyme and its derivative that self-assembles to form ribozyme oligomers. In a comparative activity assay using PEG as a molecular crowder, PEG rescued mutations in the parent bimolecular ribozyme more effectively than those in the oligomeric form.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Prolonged MEK inhibition leads to acquired resistance and increased invasiveness in KRAS mutant gastric cancer

Highlights: • MAPK pathway is important for the survival of KRAS mutant gastric cancer cells. • Prolonged MEK inhibition leads to acquired resistance. • c-MET activity is upregulated in MEK inhibitor resistant gastric cancer cells. • MEK inhibitor resistant gastric cancer cells harbor more invasive phenotype. • The increased invasiveness is abrogated by c-MET TKI or PI3K/mTOR dual inhibitor. Gastric cancer (GC) is one of the most common causes of cancer-associated death. However, traditional therapeutic strategies have failed to significantly improve the survival of patient with advanced GC. While KRAS mutations have been found in some patients with gastric cancer, an effective therapy to treat KRAS-driven gastric cancer has not been established yet. To provide a rationale for clinical application of kinase inhibitors targeting RAS pathways, we first determined the sensitivity of GC cell lines harboring KRAS mutations or amplification to RAS pathway inhibitors. We found that MAPK pathway inhibitors (MEKi and ERKi) were more effective than AKT inhibitor, suggesting that KRAS-driven gastric cancer cells are dependent on MAPK pathway for survival. Further, we established a KRAS mutant GC cell line with acquired resistance to MEK inhibitors in order to mimic clinical situation of kinase inhibitor resistance. A comprehensive analysis of tyrosine phosphorylation in receptor tyrosine kinases in combination with small molecule chemical library screening revealed upregulated c-MET phosphorylation in this resistance cell line with elevated sensitivity to c-MET TKI (crizotinib) and PI3K/mTOR dual inhibitor (BEZ235). We also showed that migration and invasion of resistant cells were promoted, and crizotinib and BEZ235 could inhibit this malignant phenotype. Overall, our results indicate that prolonged MAPK pathway inhibition could result in acquired resistance which is associated with increased malignant phenotype in KRAS mutant GC and pharmacological targeting c-MET and PI3K/mTOR could overcome this problem.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Engineering and evolution of Yarrowia lipolytica for producing lipids from lignocellulosic hydrolysates

Yarrowia lipolytica, an oleaginous yeast, shows promise for industrial fermentation due to its robust acetyl-CoA flux and well-developed genetic engineering tools. However, its lack of an active xylose metabolism restricts the conversion of cellulosic sugars to valuable products. To address this, metabolic engineering, and adaptive laboratory evolution (ALE) were applied to the Y. lipolytica PO1f strain, resulting in an efficient xylose-assimilating strain (XEV). Whole-genome sequencing (WGS) of the XEV followed by reverse engineering revealed that the amplification of the heterologous oxidoreductase pathway and a mutation in the GTPase-activating protein gene (YALI0B12100g) might be the primary reasons for improved xylose assimilation in the XEV strain. When a sorghum hydrolysate was used, the XEV strain showed superior xylose consumption and lipid production compared to its parental strain (X123). This study advances our understanding of xylose metabolism in Y. lipolytica and proposes effective metabolic engineering strategies for optimizing lignocellulosic hydrolysates.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Water vapor sorption isotherms, pore structure, and moisture transport characteristics of alkali-activated and Portland cement-based binders

Moisture transport plays a key role in determining the different durability-related features of cementitious materials. In this paper, moisture sorption in a range of low-calcium (geopolymer-type) and calcium-rich alkali-activated binders are studied and compared with that of Portland cement-based binders. Through the analysis of water vapor sorption isotherms (WVSI) and mercury intrusion porosimetry (MIP) test results, two vastly different pore structures were observed. Fly ash-based geopolymer-type binders showed a very porous structure where a large volume of mesopores coexisted with a significant volume of macropores. Alkali-activated slag binders, however, had a very fine pore structure, with a relative lack of large macropores. The different pore structure of fly ash-based and slag-based binders led to amplification of pore blocking and cavitation in blended systems by the addition of slag. Analysis of the sorption kinetics showed the prominent effect of the presence of calcium in the matrix to reduce the permeability.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Intensive and extensive margins of the peak load: Measuring adaptation with mixed frequency panel data

In this work we investigate the response of daily electricity peak load to daily maximum temperatures across states in Europe and India. We propose a method that decomposes short- from medium/long-run effects, retains the high frequency nature of the load-weather covariation and treats economic growth as a modulating factor. By simultaneously exploiting variation in unexpected daily weather anomalies and decade-long climatic changes in each location we decompose transitory - intensive margin - adjustments from permanent - extensive margin - adjustments. We find that the shocks over the long-run differ substantially from the short-run dynamics. Furthermore, we find evidence that per capita income modulates the adjustments over the short- and long-run. We project that in response to climate change around 2050 the peak load may increase by up to 20%-30% in Southern Europe and in several states in India, depending on the degree of warming and the evolution of socio-economic conditions. Even with a limited scope to two world regions, we identify that the structure of the economy and differences in future income growth matter in shaping the adaptation to climate change. Our decomposition allows to identify how future weather anomalies can further amplify the relative increase associated to the shift in the climate norm. Assuming that the interannual variability of maximum temperatures follows the distribution observed in the past, we find a doubling of the impacts of climate change during the summer in Europe. Uncertainty around the distribution of future weather anomalies may lead to further unexpected peak load amplifications. Our results have important policy implications for power systems’ generation capacity, transmission and storage, as we show that the challenges to accommodate the peak load in days with extreme temperatures may substantially increase already around mid-century.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗