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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Simultaneous Integrated Boost Volumetric Modulated Arc Therapy in the Postoperative Treatment of High-Risk to Intermediate-Risk Endometrial Cancer: Results of ADA II Phase 1-2 Trial

Purpose: A prospective phase 1-2 clinical trial aimed at determining the recommended postoperative dose of simultaneous integrated boost volumetric modulated arc therapy (SIB-VMAT) in a large series of patients with high-risk and intermediate-risk endometrial cancer (HIR-EC) is presented. The study also evaluated the association between rate and severity of toxicity and comorbidities and the clinical outcomes. Methods and Materials: Two SIB-VMAT dose levels were investigated for boost to the vaginal vault, whereas the pelvic lymph nodes were always treated with 45 Gy. The first cohort received a SIB-VMAT dose of 55 Gy in 25 consecutive 2.2-Gy fractions, and the subsequent cohort received higher doses (60 Gy in 2.4-Gy fractions). Results: Seventy consecutive HIR-EC patients, roughly half of whom were obese (47.1%) or overweight (37.1%), with Charlson Age-Comorbidity Index >2 (48.5%), were enrolled. Thirty-one patients (44.3%) were administered adjuvant chemotherapy before starting radiation therapy. All patients (n=35 per dose level) completed irradiation without any dose-limiting toxicity. Proctitis (any grade) was associated with radiation therapy dose (P=.001); not so enterocolitis. Grade ≥2 gastrointestinal (GI) and genitourinary (GU) toxicity were recorded in 17 (24.3%) and 14 patients (20.0%), respectively, and were not associated with radiation dose. As for late toxicity, none of patients experienced late grade ≥3 GI or grade ≥2 GU toxicity. The 3-year late grade ≥2 GI and GU toxicity–free survival were 92.8% and 100%, respectively, with no difference between the 2 dose levels. With a median follow-up period of 25 months (range, 4-60 months), relapse/progression of disease was observed in 10 of 70 patients (14.2%). The 3-year cumulative incidence of recurrence was 1.5% (95% confidence interval (CI): 0.2-10.7), whereas the 3-year disease-free survival was 81.3% (95% CI: 65.0-90.0). Conclusions: This clinical study showed the feasibility of this technique and its good profile in terms of acute and late toxicity at the recommended doses even in aged and frail patients.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2022

Deciphering the Dynamic Molecular Program of Radiation-Induced Endothelial Senescence

Radiation-induced cellular senescence is a double-edged sword, acting as both a tumor suppression process limiting tumor proliferation, and a crucial process contributing to normal tissue injury. Endothelial cells play a role in normal tissue injury after radiation therapy. Recently, a study observed an accumulation of senescent endothelial cells (ECs) around radiation-induced lung focal lesions following stereotactic radiation injury in mice. However, the effect of radiation on EC senescence remains unclear because it depends on dose and fractionation, and because the senescent phenotype is heterogeneous and dynamic.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Interfacial study of the role of SiO 2 on Si anodes using electrochemical quartz crystal microbalance

One of the challenges associated with silicon as an anode material for Li-ion batteries is the formation of an unstable solid-electrolyte interphase which, forms continuously while consuming lithium and other components; and consequently contributes to irreversible capacity. To elucidate some of the details of the formation and subsequent dissolution of species formed during lithiation of silicon anodes we have produced thin film silicon electrodes and analyzed them during lithiation and delithiation using an electrochemical quartz microbalance with in-situ dissipation (EQCM-D). Measurements were conducted on electrodes with silicon alone and silicon with a silicon dioxide coating, and in EC:EMC and EC:DEC:FEC based electrolytes. Mass loss during lithiation was observed in both solvents systems when an oxide layer was present on the surface of the electrode. Solid state and solution NMR measurements indicate that the formation and dissolution of Li2O is the most likely cause of mass loss.

Anodes↗
DOE OSTI2019

Analysis of electrolyte imbibition through lithium-ion battery electrodes

A quantitative measurement of wettability between the porous electrode and the electrolyte in lithium-ion batteries can greatly improve our understanding of wetting behavior. Although the wetting balance method is widely used to measure the electrolyte transport rate in the porous electrodes, it suffers from several drawbacks and has limited accuracy. We here presented a combined experimental and theoretical investigation of the dynamics of electrolyte imbibition through electrodes. We suggested a novel method to accurately measure the electrolyte imbibition rate. Excellent agreement between the experimental data and the developed analytical model is obtained. The coefficient of penetrance (COP) and the solid permeability coefficient (SPC) are identified as important parameters, i.e., the electrolyte with higher COP value wets faster into an electrode, whereas for an electrolyte, the electrode with higher SPC value is more amenable to be impregnated. The effect of electrolyte salt concentration and electrolyte solvent has been studied in detail. The result implies that increasing salt concentration adversely influences electrolyte wetting rate, whereas switching from EC-DEC system to EC-EMC system improves electrolyte wetting rate. Moreover, for the electrolytes tested in this study, the imbibition into the uncalendered graphite anode is much faster than that into the uncalendered NMC532 cathode.

25 ENERGY STORAGE↗
DOE OSTI2026

Hierarchical low Pt-loading “core-shell” electrocatalysts for the oxygen reduction reaction in fuel cells

The sluggish kinetics of the oxygen reduction reaction (ORR) hinder cost-effective polymer electrolyte fuel cells (PEFCs), which rely on scarce, expensive platinum-based electrocatalysts (ECs). Here, we present a novel synthesis method for ORR ECs achieving exceptional platinum utilization. The design features a hierarchical “multi-carbon” support comprising carbon nanoparticles interacting with graphene nanoplatelets as the “core”, encapsulated by a porous carbon nitride (CN) “shell”. This configuration promotes strong core/shell interactions and a bimodal active site distribution, consisting of chemically dispersed Pt and Ni single-atom complexes and PtNix alloy nanoclusters embedded in the CN shell. These advantages enable high activity and durability, achieving an ORR activity of 1.6 A mgPt−1 at 0.9 V vs. RHE-an order of magnitude higher than Pt/C (0.17 A mgPt−1). A proof-of-concept PEFC demonstrates a specific power of 12.0 kW gPt−1 at 0.60 V. This approach offers a significant step toward more efficient and sustainable PEFC technologies.

Pagot, Gioele [University of Padova, Italy]↗
DOE OSTI2026

Solvation-guided inhibition of manganese dissolution of lithium- and manganese- rich cathode via cyclic carbonate molecular engineering

Lithium and manganese-rich (LMR) layered oxides represent a leading class of high-energy cathode materials, but their practical realization is fundamentally limited by severe manganese (Mn) dissolution, a process that triggers structural degradation and rapid capacity fade. While mitigation efforts have predominantly focused on interfacial engineering, the intrinsic contribution of bulk electrolyte solvation to this degradation pathway remains largely unexplored, primarily due to the difficulty of deconvolving its effects from concurrent cathode-electrolyte interphase (CEI) formation. Here, we report an experimental design to isolate the role of solvation. We systematically varied the electrolyte solvent solvation power by substituting the strongly coordinating ethylene carbonate (EC) with its weaker coordinating fluorinated derivatives, fluoroethylene carbonate (FEC) and trans-4,5-Difluoro-1,3-dioxolan-2-one (DFEC), while maintaining a consistent interfacial chemistry. Remarkably, the electrolyte formulated with the weakest solvent, DFEC, exhibits superior cycling stability, suppressing Mn dissolution by up to 63% relative to the conventional EC-based system. Post-mortem analysis unequivocally attributes this performance enhancement to the preservation of the LMR cathode's structural integrity, a direct consequence of mitigated Mn dissolution. This work provides conclusive evidence that modulating bulk electrolyte solvation is a potent and direct strategy for stabilizing LMR cathodes, establishing a vital design principle for next-generation battery systems.

25 ENERGY STORAGE↗
DOE OSTI2017

Dosimetric benefits of automation in the treatment of lower thoracic esophageal cancer: Is manual planning still an alternative option?

This study aimed to design automated volumetric-modulated arc therapy (VMAT) plans in Pinnacle auto-planning and compare it with manual plans for patients with lower thoracic esophageal cancer (EC). Thirty patients with lower thoracic EC were randomly selected for replanning VMAT plans using auto-planning in Pinnacle treatment planning system (TPS) version 9.10. Historical plans of these patients were then compared. Dose-volume histogram (DVH) statistics, dose uniformity, and dose homogeneity were analyzed to evaluate treatment plans. Auto-planning was superior in terms of conformity index (CI) and homogeneity index (HI) for planning target volume (PTV), significantly improving 8.2% (p = 0.013) and 25% (p = 0.007) compared with manual planning, respectively, and decreasing dose of heart and liver irradiated by 20 to 40 Gy and 5 to 30 Gy, respectively (p max ) of spinal cord by 6.9 Gy compared with manual planning (p = 0.000). Additionally, manual planning showed the significantly lower low-dose volume (V{sub 5}) for the lung (p = 0.005). For auto-planning, the V{sub 5} of the lung was significantly associated with the relative volume index (the volume ratio of PTV to the lung), and the correlation coefficient (R) and p-value were 0.994 and 0.000. Pinnacle auto-planning achieved superior target conformity and homogeneity and similar target coverage compared with historical manual planning. Most of organs at risk (OARs) sparing was significantly improved by auto-planning except for the V{sub 5} of the lung, and the low dose distribution was highly associated with PTV volume and lung volume in auto-planning.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2018

Role of structural hydroxyl groups in enhancing performance of electrochemically-synthesized bilayer V 2 O 5

Nanostructured electrode materials represent a promising path forward to dramatically improving the performance of both Li-ion and beyond Li-ion battery systems; however, difficulties in characterizing the structural and electrochemical changes that take place in nanoscale systems, which are often poorly crystalline or amorphous, make it difficult to develop design rules for synthesizing new materials with optimal performance. Bilayered vanadium oxide-based materials (BL-V 2 O 5 ) are an ideal platform for understanding the underlying physicochemical properties that determine capacity in nanomaterials, with electrochemically-synthesized V 2 O 5 (EC-V 2 O 5 ) exhibiting particularly high capacities. In this work we provide evidence that the source of high practical capacity in EC-V 2 O 5 is the presence of “structural hydroxyl groups” that are an intrinsic feature of the electrochemical synthesis method. Using both in situ and ex situ characterization methods, we demonstrate that structural OH species are highly stable and persist in the structure during reversible cycling. We hypothesize three important roles for structural OH groups: they maintain a sufficient interlayer spacing to allow the physical diffusion of cations over multiple cycles; they maintain a consistent solvating environment in the bilayer regardless of structural H 2 O content; and they reduce the symmetry of vanadium polyhedra to favor electron transfer over pseudocapacitive adsorption, making it possible to access close to theoretical capacity. Furthermore, these insights have broad implications for understanding the performance of a variety of hydrated oxide systems, and indicate that the formation of covalently-bound hydroxyoxide species can lead to further improvements in the performance of nanoscale materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

The CLAS12 forward electromagnetic calorimeter

The CLAS12 Forward Detector includes six independent lead-scintillator electromagnetic sampling calorimeters to provide the primary electron trigger and extend the CLAS12 detection capability to photons and neutrons. Each calorimeter package consists of two modules, the legacy Electromagnetic Calorimeter (EC) previously used in the CLAS detector, and a new pre-shower calorimeter (PCAL) located in front of the EC to extend the total detector radiation length, in order to fully absorb the electromagnetic showers induced by electrons with energies up to 12 GeV. Both calorimeters use a novel triangular hodoscope geometry with stereo readout. The PCAL uses an upgraded design to provide the high spatial resolution necessary for reconstructing π 0 and η decays, and neutrons with high efficiency. Here, this paper treats the design, construction, and calibration of the PCAL and the preliminary combined performance of both detectors.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Plasmonic Ag nanocomposite phosphate glasses produced via γ-ray irradiation as reduction route

This paper reports on the impact of γ-ray irradiation (10, 100 kGy) on melt-quenched Ag + -doped phosphate glass and the effects of subsequent thermal processing leading to the production of plasmonic Ag nanocomposites. The γ-irradiated glasses were characterized alongside the pristine by differential scanning calorimetry (DSC), Raman spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, optical absorption, and photoluminescence (PL) spectroscopy. DSC characterization showed consistent glass transition temperatures (T g ) before and after γ-irradiation whereas the crystallization temperatures tended to decrease with increasing γ-ray dose. However, a lack of alteration of the glass network structure was supported by Raman spectroscopy. Room temperature EPR spectra clearly showed the formation of phosphorus oxygen hole center (POHC) defects in the undoped host, in addition to another doublet likely associated with a P 3 defect. The presence of paramagnetic silver species encompassing Ag 2+ and 107/109 Ag 0 atoms was also indicated in the silver-activated glass together with POHC defects. Optical absorption spectra were also consistent with the presence of various radiation-induced centers. Further analyzing the glass absorption edge via Tauc plots suggested the formation of electron center (EC) defects in γ-irradiated samples wherein the silver-doped glass exhibited decreasing band gap energies with increasing γ-ray dose. The PL characterization showed the silver-related radio-PL effect was induced exhibiting broad band emission with two maxima around 500 and 625 nm stemming from various molecular Ag$^{x+}_{n}$ clusters. Emission decay analyses revealed that the longer wavelength emission exhibited slower decay. The highest radiation dose of 100 kGy however resulted in weaker emission and faster decay kinetics attributed to energy transfer between the luminescent silver species and POHC defects. Finally subjecting the γ-irradiated Ag-doped glasses to heat treatment near the T g at 490 °C led to the development of the surface plasmon resonance of Ag nanoparticles (NPs) and the vanishing of the Ag$^{x+}_{n}$ clusters luminescence. In conclusion, the presence of the matrix-related EC defects was deemed accountable for the thermally induced reduction and consequent precipitation of Ag NPs making the plasmonic glasses attractive for photonic applications such as nonlinear optics.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Possible excitonic phase of (Pr 1-y R y ) 1-x Ca x CoO 3 (R = Lanthanides and Y)

(Pr 1-y R y ) 1-x Ca x CoO 3 (R = Y and/or Lanthanide elements) exhibits a “hidden order transition” in the ( x, y ) region near (0.5, 0.0) at temperature T s , where none of magnetic ordering and change of the space group have been found, even though significant anomalies in various physical quantities exist. When the ( x, y ) is outside of the above region, the transition can essentially be understood by the spin-state-crossover of isolated Co atoms. To study whether excitonic condensation (EC) recently proposed is relevant to the “hidden order transition”, we measured magnetic excitation spectra χ” (Q, ω) by means of inelastic neutron scattering on a single crystal of (Pr 0.8 Y 0.2 ) 0.7 Ca 0.3 CoO 3 , and obtained following results: While the spectra from the Co 3d electrons observed at 200 K (>above T s ) have characteristics of ordinary strongly correlated electron systems, the χ” (Q, ω) - ω curve at 4 K (< T s ) has a feature reminiscent, at first sight, of a weak pseudogap-like structure. This result can be explained by the realization of the EC phase or “EIQ” phase or at least by the picture that the system is in the boundary region between the low-spin and EQI"phases. Finally, this result strongly suggests that there exists the EIQ phase in the present sample or at least in (Pr 1–y R y ) 1–x Ca x CoO 3 with ( x, y ) near (0.5, 0.0).

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Allosteric modulators of the hERG K{sup +} channel

Drugs that block the cardiac K{sup +} channel encoded by the human ether-à-go-go gene (hERG) have been associated with QT interval prolongation leading to proarrhythmia, and in some cases, sudden cardiac death. Because of special structural features of the hERG K{sup +} channel, it has become a promiscuous target that interacts with pharmaceuticals of widely varying chemical structures and a reason for concern in the pharmaceutical industry. The structural diversity suggests that multiple binding sites are available on the channel with possible allosteric interactions between them. In the present study, three reference compounds and nine compounds of a previously disclosed series were evaluated for their allosteric effects on the binding of [{sup 3}H]astemizole and [{sup 3}H]dofetilide to the hERG K{sup +} channel. LUF6200 was identified as an allosteric inhibitor in dissociation assays with both radioligands, yielding similar EC{sub 50} values in the low micromolar range. However, potassium ions increased the binding of the two radioligands in a concentration-dependent manner, and their EC{sub 50} values were not significantly different, indicating that potassium ions behaved as allosteric enhancers. Furthermore, addition of potassium ions resulted in a concentration-dependent leftward shift of the LUF6200 response curve, suggesting positive cooperativity and distinct allosteric sites for them. In conclusion, our investigations provide evidence for allosteric modulation of the hERG K{sup +} channel, which is discussed in the light of findings on other ion channels. - Highlights: • Allosteric modulators on the hERG K{sup +} channel were evaluated in binding assays. • LUF6200 was identified as a potent allosteric inhibitor. • Potassium ions were found to behave as allosteric enhancers. • Positive cooperativity and distinct allosteric sites for them were proposed.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Additive and synergistic antiandrogenic activities of mixtures of azol fungicides and vinclozolin

Objective: Many pesticides including pyrethroids and azole fungicides are suspected to have an endocrine disrupting property. At present, the joint activity of compound mixtures is only marginally known. Here we tested the hypothesis that the antiandrogenic activity of mixtures of azole fungicides can be predicted by the concentration addition (CA) model. Methods: The antiandrogenic activity was assessed in MDA-kb2 cells. Following assessing single compounds activities mixtures of azole fungicides and vinclozolin were investigated. Interactions were analyzed by direct comparison between experimental and estimated dose–response curves assuming CA, followed by an analysis by the isobole method and the toxic unit approach. Results: The antiandrogenic activity of pyrethroids deltamethrin, cypermethrin, fenvalerate and permethrin was weak, while the azole fungicides tebuconazole, propiconazole, epoxiconazole, econazole and vinclozolin exhibited strong antiandrogenic activity. Ten binary and one ternary mixture combinations of five antiandrogenic fungicides were assessed at equi-effective concentrations of EC{sub 25} and EC{sub 50}. Isoboles indicated that about 50% of the binary mixtures were additive and 50% synergistic. Synergism was even more frequently indicated by the toxic unit approach. Conclusion: Our data lead to the conclusion that interactions in mixtures follow the CA model. However, a surprisingly high percentage of synergistic interactions occurred. Therefore, the mixture activity of antiandrogenic azole fungicides is at least additive. Practice: Mixtures should also be considered for additive antiandrogenic activity in hazard and risk assessment. Implications: Our evaluation provides an appropriate “proof of concept”, but whether it equally translates to in vivo effects should further be investigated. - Highlights: • Humans are exposed to pesticide mixtures such as pyrethroids and azole fungicides. • We assessed the antiandrogenicity of pyrethroids and azole fungizides. • Many azole fungicides showed significant antiandrogenic activity . • Many binary mixtures of antiandrogenic azole fungicides showed synergistic interactions. • Concentration addition of pesticides in mixtures should be considered.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

A comprehensive evaluation of novel oximes in creation of butyrylcholinesterase-based nerve agent bioscavengers

A well-considered treatment of acute nerve agents poisoning involves the exogenous administration of butyrylcholinesterase (BChE, EC 3.1.1.8) as a stoichiometric bioscavenger efficient in preventing cholinergic crises caused by acetylcholinesterase (AChE, EC 3.1.1.7) inhibition. An additional improvement in medical countermeasures would be to use oximes that could reactivate BChE as well to upgrade bioscavenging from stoichiometric to oxime-assisted catalytic. Therefore, in this paper we investigated the potency of 39 imidazolium and benzimidazolium oximes (36 compounds synthesized for the first time) to be considered as the reactivators specifically designed for reactivation of phosphylated human BChE. Their efficiency in the reactivation of paraoxon-, VX-, and tabun-inhibited human BChE, as well as human AChE was tested and compared with the efficiencies of HI-6 and obidoxime, used in medical practice today. A comprehensive analysis was performed for the most promising oximes defining kinetic parameters of reactivation as well as interactions with uninhibited BChE. Furthermore, experimental data were compared with computational studies (docking, QSAR analysis) as a starting point in future oxime structure refinement. Considering the strict criteria set for in vivo applications, we determined the cytotoxicity of lead oximes on two cell lines. Among the tested oxime library, one imidazolium compound was selected for preliminary in vivo antidotal study in mice. The obtained protection in VX poisoning outlines its potential in development oxime-assisted OP-bioscavenging with BChE. - Highlights: • 36 new imidazolium and benzimidazolium oximes were designed and synthesized. • In vitro reactivation kinetics of phosphylated butyrylcholinesterase was studded. • The modes of actions were elucidated by QSAR and docking simulations. • Protection in VX poisoning was 6.3 × LD{sub 50} in in vivo antidotal study in mice. • Imidazolium oxime-assisted catalysis is feasible for OP-bioscavenging with BChE.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Olive oil compounds inhibit vascular endothelial growth factor receptor-2 phosphorylation

Vascular endothelial growth factor (VEGF) triggers crucial signaling processes that regulate tumor angiogenesis and, therefore, represents an attractive target for the development of novel anticancer therapeutics. Several epidemiological studies have confirmed that abundant consumption of foods from plant origin is associated with reduced risk of developing cancers. In the Mediterranean basin, the consumption of extra virgin olive oil is an important constituent of the diet. Compared to other vegetable oils, the presence of several phenolic antioxidants in olive oil is believed to prevent the occurrence of a variety of pathological processes, such as cancer. While the strong antioxidant potential of these molecules is well characterized, their antiangiogenic activities remain unknown. The aim of this study is to investigate whether tyrosol (Tyr), hydroxytyrosol (HT), taxifolin (Tax), oleuropein (OL) and oleic acid (OA), five compounds contained in extra virgin olive oil, can affect in vitro angiogenesis. We found that HT, Tax and OA were the most potent angiogenesis inhibitors through their inhibitory effect on specific autophosphorylation sites of VEGFR-2 (Tyr951, Tyr1059, Tyr1175 and Tyr1214) leading to the inhibition of endothelial cell (EC) signaling. Inhibition of VEGFR-2 by these olive oil compounds significantly reduced VEGF-induced EC proliferation and migration as well as their morphogenic differentiation into capillary-like tubular structures in Matrigel. Our study demonstrates that HT, Tax and OA are novel and potent inhibitors of the VEGFR-2 signaling pathway. These findings emphasize the chemopreventive properties of olive oil and highlight the importance of nutrition in cancer prevention. - Highlights: • We investigated five compounds contained in extra virgin olive oil on angiogenesis. • Hydroxytyrosol, taxifolin and oleic acid are the best angiogenesis inhibitors. • Olive oil compounds affect endothelial cell functions essential for angiogenesis. • Olive oil compounds inhibit specific autophosphorylation sites of VEGFR-2. • Hydroxytyrosol, taxifolin and oleic acid inhibit VEGFR-2 signaling pathway.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Exosomes derived from endothelial progenitor cells ameliorate acute lung injury by transferring miR-126

Highlights: • Administration of EPC-Exos ameliorated LPS-induced ALI and restored the in vivo lung integrity. • The microRNA miR-126 was enriched in EPC-Exos and the abilities of EPC-Exos to protect against LPS were relayed by the horizontal shuttled miR-126. • Transferred miR-126 to target endothelial cells downregulated SPRED1 and implicated RAF/ERK signaling pathways in the reparative process in rat model of lung injury. Endothelial progenitor cell (EPC) has potential to attenuate pulmonary inflammation and injury. As a pivotal paracrine entity of stem cells, whether EPC-derived exosomes (EPC-Exos) contribute to acute lung injury (ALI) remains unknown. Exosomes were purified from conditional medium of EPCs, and then characterized by electron micrograph and immunoblotting. A model of ALI was induced by lipopolysaccharide (LPS) and then rats were transplanted with EPC-Exos. The underlying mechanisms of action of EPC-Exos were examined in vitro endothelial functional assays including the TEER, proliferation (CKK-8), angiogenesis and migration. A possible underlying mechanism was examined by western blotting and further animal studies. Administration of EPC-Exos ameliorated LPS-induced ALI and restored the in vivo pulmonary integrity. EPC-Exos enhanced the proliferation, migration and tube formation of the endothelial cells (ECs). Furthermore, we found that miR-126 was enriched in EPC-Exos and can be delivered onto ECs. Modification of EPCs through miR-126 knockdown can diminish their exosomes function in vitro, indicative of the abilities of EPC-Exos to protect against LPS were inherited by the horizontal shuttled miR-126. Luciferase reporter assays confirmed that miR-126 could target SPRED1. Additionally, the miR-126 transferred to target endothelial cells resulted in subsequent downregulation of SPRED1 and promoted RAF/ERK signaling pathways and subsequent improvement in endothelial cell function. Our study revealed a novel role of exosomal miRNAs in EPC-mediated therapy, suggesting that the clinical application of EPC-Exos might represent a strategy in ALI/ARDS.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Validation of reference genes for real-time PCR of cord blood mononuclear cells, differentiating endothelial progenitor cells, and mature endothelial cells

Highlights: • RT-qPCR was used to assess and follow the differentiation of EPCs. • A set of reliable and non-variable genes is key to obtain accurate RT-qPCR results. • The relative gene expression of CD34+ and differentiating endothelial progenitor cells was determined. • The optimal set of reference for the gene expression studies performed by RT-qPCR was determined. In the last ten years, endothelial progenitor cells (EPCs) have gained interest as an attractive cell population in regenerative medicine for vascular applications. This population is defined as the precursor of endothelial mature cells (ECs) through a process of differentiation. To our knowledge, no single marker can be used to discriminate them from mature ECs. To effectively study their differentiation kinetics, gene expression must be assessed. Quantitative real-time PCR (RT-qPCR) is widely used to analyze gene expression. To minimize the impact of variances from RT-qPCR, a rigorous selection of reference genes must be performed prior to any experiments due to variations in experimental conditions. In this study, CD34+ mononuclear cells were extracted from human cord blood and differentiated into EPCs after seeding for a maximum period of 21 days. To choose the best combinations of reference genes, we compared the results of EPCs, CD34+ mononuclear cells, and mature endothelial cells to ensure that the differentiation kinetics did not affect the expression of our selected reference genes. The expression levels of seven genes, namely, YWHAZ, GAPDH, HPRT1, RPLP0, UBC, B2M, and TBP were thus compared. The algorithms geNorm, NormFinder, BestKeeper, and the Comparative ΔCt method were employed to assess the expression of each candidate gene. Overall results reveal that the expression stability of reference genes may differ depending on the statistical program used. YWHAZ, GAPDH, and UBC composed the optimal set of reference genes for the gene expression studies performed by RT-qPCR in our experimental conditions. This work can thus serve as a starting point for the selection of candidate reference genes to normalize the levels of gene expression in endothelial progenitor cell populations.

60 APPLIED LIFE SCIENCES↗