Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “LAN”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Epstein-Barr virus Rta promotes invasion of bystander tumor cells through paracrine of matrix metalloproteinase 9

Highlights: • Rta-expressing cells promote invasion of bystander tumor cells through paracrine. • Rta upregulates MMP9 expression through activation of E2F. • The Rta-induced, paracrine-mediated pro-invasive effect is blocked upon knockdown or inhibition of MMP9. Clinical studies suggest a positive association between malignant progression of nasopharyngeal carcinoma (NPC) and Rta, a transcription factor of Epstein-Barr virus (EBV). However, Rta induces cellular senescence in vitro. To provide an underlying mechanism integrating these clues, we adapted a concept of senescence-associated secretory phenotype (SASP), based on which senescent cells facilitate tumor progression through paracrine. First, Rta-expressing NPC cells themselves show reduced invasiveness but promote invasion of Rta-negative tumor cells through secreted factors. Secretion of matrix metalloproteinase 9 (MMP9), an SASP protein, is increased by Rta, which requires the C-terminus of Rta and Rta-induced activation of E2F. Furthermore, the Rta-induced, paracrine-mediated pro-invasive effect is blocked upon knockdown of MMP9 expression or treatment with an MMP9 inhibitor. This study not only indicates that Rta can contribute to NPC progression through paracrine but also supports that MMP9 is a potential therapeutic target to prevent NPC metastasis.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

NKILA inhibition protects retinal pigment epithelium cells from hypoxia by facilitating NFκB activation

Highlights: • Hypoxia induces NKILA expression in retinal pigment epithelium (RPE) cells. • Hypoxia induces NKILA-IκBα association and NFκB activation in RPE cells. • NKILA shRNA inhibits hypoxia-induced RPE cell death. • NKILA overexpression potentiates hypoxia-induced RPE cell death. • miR-103 inhibition by hypoxia could be a primary reason of NKILA upregulation. Sustained retinal hypoxia causes injuries to retinal pigment epithelium (RPE) cells. We studied expression and potential functions of nuclear factor-κB (NFκB) Interacting LncRNA (NKILA) in hypoxia-treated RPE cells. Hypoxia induced NKILA expression, NKILA-IκBα association and NFκB activation in ARPE-19 cells and primary human RPE cells. shRNA-mediated knockdown of NKILA facilitated NFκB activation, inhibiting RPE cell death and apoptosis. Conversely, exogenous overexpression of NKILA blocked hypoxia-induced NFκB activation, thereby exacerbating RPE cell apoptosis. Further studies show that hypoxia downregulated microRNA-103 (miR-103), the anti-NKILA microRNA, in RPE cells. Transfection of miR-103 mimic blocked hypoxia-induced NKILA expression to significantly boost NFκB activation, protecting RPE cells from hypoxia. Collectively, we conclude that hypoxia-induced NKILA expression negatively regulates NFκB to promote RPE cell death. Conversely, NKILA inhibition protects RPE cells from hypoxia by facilitating NFκB activation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

MUC16 mutation predicts a favorable clinical outcome and correlates decreased Warburg effect in gastric cancer

Highlights: • Identification of mutations related to the glycolytic phenotype of GC. • Mutated MUC16 predicts a better prognosis and inversely correlates with glycolysis in GC. • Genetic silencing of MUC16 in GC blocks glycolysis in GC cells. • MUC16 correlates PI3K/AKT/mTOR signaling pathway in GC cells. Mutations in oncogenes or tumor suppressors can reprogram tumor metabolism by controlling multiple metabolic changes including glycolysis, glutaminolysis, increased autophagy, and macropinocytosis. Somatic mutations are essential for the development and growth of gastric cancer (GC), but the precise roles of these mutations in GC glucose metabolism remain largely unknown. In this study, we examined cancer genomes in 375 GC samples and demonstrated several glycolysis-related mutations in GC. Of note, loss-of-function mutation in MUC16 gene was identified. Mutated MUC16 predicted a better prognosis in GC patients. Gene set enrichment analysis suggested that mutated MUC16 status was associated with down-regulation of PI3K/Akt/mTOR signaling and Myc expression. GC cells with MUC16 mutations had reduced glycolytic capacity. Subsequently, genetic silencing of MUC16 in SNU16 and SNU5 cells led to significant reduction in glucose uptake, lactate production, extracellular acidification rate, and colony formation ability, indicating the critical regulatory roles of MUC16 in GC glycolysis and tumorigenesis. Specifically, western blotting showed that MUC16 knockdown inhibited PI3K/Akt/mTOR signaling, and reduced the protein level of Myc, which acts as a key transcription factor in regulating glycolysis. Taken together, our findings identify the MUC16-PI3K/Akt/mTOR-Myc axis as a critical signaling cascade that couples genomic mutations to metabolic reprogramming in GC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Comparative study of lignin characteristics from wheat straw obtained by soda-AQ and kraft pretreatment and effect on the following enzymatic hydrolysis process

With this study, to understand the structural changes of lignin after soda-AQ and kraft pretreatment, milled straw lignin, black liquor lignin and residual lignin extracted from wheat straw were characterized by FT-IR, UV, GPC and NMR. The results showed that the main lignin linkages were β-aryl ether substructures (β-O-4'), followed by phenylcoumaran (β-5') and resinol (β-β') substructures, while minor content of spirodienone (β-1'), dibenzodioxocin (5-5') and α,β-diaryl ether linkages were detected as well. After pretreatment, most lignin inter-units and lignin-carbohydrate complex (LCC) linkages were degraded and dissolved in black liquor, with minor amount left in residual pretreated biomass. In addition, through quantitative 13 C and 2D-HSQC NMR spectral analysis, lignin and LCC were found to be more degraded after kraft pretreatment than soda-AQ pretreatment. Furthermore, the subsequent enzymatic hydrolysis results showed that more cellulose in wheat straw was converted to glucose after kraft pretreatment, indicating that LCC linkages were important in the enzymatic hydrolysis process.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Adsorption of cellobiohydrolases I onto lignin fractions from dilute acid pretreated Broussonetia papyrifera

Broussonetia papyrifera, known as paper mulberry, is a potential feed stock for bioethanol production because of its cellulose-rich composition. Lignin in dilute acid pretreated Broussonetia papyrifera was fractionated to three different fractions, and their physiochemical properties were determined by FT-IR, GPC and NMR analyses. Different structural characteristics were observed from each lignin fraction. Cellobiohydrolases I (CBH) adsorption to each lignin was understood by the lignin properties. The results showed that aliphatic hydroxyl groups in lignin showed positive correlations with the maximum binding ability of CBH onto lignin samples. Also, the contents of phenolic compounds such as p-hydroxyphenyl benzoate (PB), syringyl (S) and guaiacyl (G) units in the lignin influenced their CBH binding.

09 BIOMASS FUELS↗
DOE OSTI2018

Understanding the influences of different pretreatments on recalcitrance of Populus natural variants

Here, four different pretreatment technologies were applied to two Populus natural variants and the effects of each pretreatment on glucose release were compared. Physicochemical properties of pretreated biomass were analyzed by attenuated total reflection Fourier transform infrared spectroscopy, gel permeation chromatography, and cross polarization/magic angle spinning carbon-13 nuclear magnetic resonance techniques. The results revealed that hemicellulose and lignin were removed to different extents during various pretreatments. The degree of polymerization of cellulose was decreased in the order of alkali > hydrothermal > organosolv > dilute acid pretreatment. Cellulose crystallinity index was slightly increased after each pretreatment. The results also demonstrated that organosolv pretreatment resulted in the highest glucose yield. Among the tested properties of Populus , degree of polymerization of cellulose was negatively correlated with glucose release, whereas hemicellulose and lignin removal, and cellulose accessibility were positively associated with glucose release from the two Populus natural variants.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Structural changes of lignins in natural Populus variants during different pretreatments

In the present study, three leading pretreatment technologies including dilute acid (DA), liquid hot water (LHW), and organosolv pretreatments (OS) were applied on two Populus natural variants with different recalcitrance. The structural features of the isolated lignins were analyzed accordingly. All the studied pretreatments reduced the molecular weights of the lignins. Aliphatic OH was reduced while phenolic OH was increased in all pretreated lignins. HSQC analysis revealed that pretreatment influenced the lignin composition and relative distribution of inter-unit linkages. The lignin S/G ratio was found to increase during DA pretreatment, while it was decreased after LHW and OS pretreatment. LHW pretreatment also resulted in much less cleavage of β-O-4 linkage than the other two pretreatments. These results could offer guidelines on appropriate selection of biomass and pretreatment technology in the future biorefinery process.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

A combination of deep eutectic solvent and ethanol pretreatment for synergistic delignification and enhanced enzymatic hydrolysis for biorefinary process

Here, a novel pretreatment system containing deep eutectic solvents and ethanol (DES-E) for synergistic carbohydrate conversion and delignification was reported in this study. The DES-E pretreatment resulted in an enhanced glucose yield compared to individual DES and ethanol pretreatment for the three tested biomass, including Broussonetia papyrifera, corn stover and pine. To further explore the delignification mechanism, the solubilized lignin and residual lignin from Broussonetia papyrifera was recovered and extracted, then thoroughly characterized. The highest total OH content was found in the DES-E solubilized lignin, which could be used as antioxidant. The presence of ethanol in pretreatment liquor could protect the β-O-4 substructure from breakage and reduce lignin condensation, which favors the subsequent enzymatic hydrolysis. Comparable glucose yield and delignification performance was achieved by recycled DES. DES-E pretreatment offers a promising method for lignin isolation and cellulose digestibility improvement simultaneously.

09 BIOMASS FUELS↗
DOE OSTI2016

Discovery of imidazo[1,2- a ]-pyridine inhibitors of pan-PI3 kinases that are efficacious in a mouse xenograft model

Alterations in PI3K/AKT signaling are known to be implicated with tumorigenesis. The PI3 kinases family of lipid kinases has been an attractive therapeutic target for cancer treatment. Imidazopyridine compound 1, a potent, selective, and orally available pan-PI3K inhibitor, identified by scaffold morphing of a benzothiazole hit, was further optimized in order to achieve efficacy in a PTEN-deleted A2780 ovarian cancer mouse xenograft model. With a hypothesis that a planar conformation between the core and the 6-heteroaryl ring will allow for the accommodation of larger 5'-substituents in a hydrophobic area under P-loop, SAR efforts focused on 5'-alkoxy heteroaryl rings at the 6-position of imidazopyridine and imidazopyridazine cores that have the same dihedral angle of zero degrees. 6'-Alkoxy 5'-aminopyrazines in the imidazopyridine series were identified as the most potent compounds in the A2780 cell line. Compound 14 with 1,1,1-trifluoroisopropoxy group at 6'-position demonstrated excellent potency and selectivity, good oral exposure in rats and in vivo efficacy in A2780 tumor-bearing mouse. Also, we disclose the X-ray co-crystal structure of one enantiomer of compound 14 in PI3Kα, confirming that the trifluoromethyl group fits nicely in the hydrophobic hot spot under P-loop.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Cancer cell membrane-coated rare earth doped nanoparticles for tumor surgery navigation in NIR-II imaging window

With the attractive characteristics of low toxicity, narrow emission spectra, long fluorescence lifetime, and no photobleaching, rare-earth doped nanoparticles (RENPs) have become promising imaging nanoplatforms in the second near-infrared window (NIR-II, 1000–1700 nm). Many studies have been devoted to different surface modification strategies of RENPs to achieve good NIR-II tumor imaging property. However, the tumor imaging efficiency of these approaches remains disappointing. Herein, two methods were pursued to modify RENPs with either polyethylene glycol (PEG) or cancer-cell-membrane to generate PEGylated-RENPs and cancer-cell-membrane camouflaged RENPs (CC-RENPs), respectively. Furthermore, this study demonstrated that cancer-cell-membrane coating of RENPs greatly improved tumor imaging performance in NIR-II window than PEG coating. Besides, CC-RENPs uptakes in liver and spleen significantly decreased. Importantly, CC-RENPs was found to be capable to aid us to pursue precise resection of the tumor. In conclusion, CC-RENPs are capable of targeting tumors and show high tumor NIR-II imaging quality. They are highly promising nanomaterials for future medical applications.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2020

Quality-Control Mechanism for Telomerase RNA Folding in the Cell

Long non-coding RNAs can often fold into different conformations. Telomerase RNA, an essential component of the telomerase ribonucleoprotein (RNP) enzyme, must fold into a defined structure to fulfill its function with the protein catalytic subunit (TERT) and other accessory factors. However, the mechanism by which the correct folding of telomerase RNA is warranted in a cell is still unknown. Here we show that La-related protein Pof8 specifically recognizes the conserved pseudoknot region of telomerase RNA and instructs the binding of the Lsm2-8 complex to its mature 3' end, thus selectively protecting the correctly folded RNA from exonucleolytic degradation. In the absence of Pof8, TERT assembles with misfolded RNA and produces little telomerase activity. Therefore, Pof8 plays a key role in telomerase RNA folding quality control, ensuring that TERT only assembles with functional telomerase RNA to form active telomerase. Our finding reveals a mechanism for non-coding RNA folding quality control.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Bioelectrochemical reactor to manage anthropogenic sulfate pollution for freshwater ecosystems: Mathematical modeling and experimental validation

Anthropogenic sulfate loading into otherwise low-sulfate freshwater systems can cause significant ecological consequences as a biogeochemical stressor. To address this challenge, in situ bioremediation technologies have been developed to leverage naturally occurring microorganisms that transform sulfate into sulfide rather than implementing resource-intensive physio-chemical processes. However, bioremediation technologies often require the supply of electron donors to facilitate biological sulfate reduction. Bioelectrochemical systems (BES) can be an alternative approach for supplying molecular hydrogen as an electron donor for sulfate-reducing bacteria through water electrolysis. Although the fundamental mechanisms behind BESs have been studied, limited research has evaluated the design and operational parameters of treatment systems when developing BESs on a scale relevant to environmental systems. Further, this study aimed to develop an application-based mathematical model to evaluate the performance of BESs across a range of reactor configurations and operational modes. The model was based on sulfate transformation by hydrogenotrophic sulfate-reducing bacteria coupled with the recovery of solid iron sulfide species formed by the oxidative dissolution of dissolved ferrous iron from a stainless steel anode. Sulfate removal closely corresponded to the rate of electrolytic hydrogen production and hydraulic residence time but was less sensitive to specific microbial rate constants. The mathematical model results were compared to experimental data from a pilot-scale BES tested with nonacidic mine drainage as a case study. The close agreement between the mathematical model and the pilot-scale BES experiment highlights the efficacy of using a mathematical model as a tool to develop a conceptual design of a scaled-up treatment system.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Radiation Controllable Synthesis of Robust Covalent Organic Framework Conjugates for Efficient Dynamic Column Extraction of 99 TcO4 -

Wang et al. report here an ultra-robust imidazolium-decorated covalent organic framework (COF) conjugate fabricated by an ionizing radiation strategy for efficient capture of 99 TcO 4 -, where tunable ReO 4 - uptake up to 952 mg g -1 can be achieved by simply adjusting the γ-ray dose. The COFs feature high porosity, ultra-robust nanofiber structure, and fast adsorption kinetics, thus emphasizing their advantages in terms of column experiments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Heterogeneous hydroformylation of alkenes by Rh-based catalysts

Heterogeneously catalyzed hydroformylation reactions avert the problems of separation in homogeneous reactions, reduce the discharge of phosphorus-containing wastes, and prevent the loss of precious metals. This review summarizes the developments of catalysts for heterogeneous hydroformylation in the last decade and proposes potential modification methods for future improvements. The hydroformylation properties of different reactants are compared in order to emphasize the fact that various olefins face unique challenges. The hydroformylation of ethylene requires the enhancement of catalytic activity and chemoselectivity, whereas that of propylene needs improvements in both chemoselectivity and regioselectivity. The hydroformylation of longer-chain olefins and styrene seeks further improvement in regioselectivity. The catalytic properties of activity, selectivity, and stability can be tuned through electronic effects (bimetallic effects, phosphine ligands, and single-atom catalysts), steric hindrance (encapsulation structures, diphosphine ligands, and local functional groups), and reaction condition optimization (temperature, pressure, and solvents). Furthermore, the understanding of these effects is critical in future catalyst design for heterogeneous hydroformylation reactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Polysaccharide utilization loci in Bacteroides determine population fitness and community-level interactions

Polysaccharide utilization loci (PULs) are co-regulated bacterial genes that sense nutrients and enable glycan digestion. Human gut microbiome members, notably Bacteroides, contain numerous PULs that enable glycan utilization and shape ecological dynamics. To investigate the role of PULs on fitness and inter-species interactions, we develop a CRISPR-based genome editing tool to study 23 PULs in Bacteroides uniformis (BU). BU PULs show distinct glycan-degrading functions and transcriptional coordination that enables the population to adapt upon loss of other PULs. Exploiting a BU mutant barcoding strategy, we demonstrate that in vitro fitness and BU colonization in the murine gut are enhanced by deletion of specific PULs and modulated by glycan availability. PULs mediate glycan-dependent interactions with butyrate producers that depend on the degradation mechanism and glycan utilization ability of the butyrate producer. Thus, PULs determine community dynamics and butyrate production and provide a selective advantage or disadvantage depending on the nutritional landscape.

59 BASIC BIOLOGICAL SCIENCES↗