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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 343 records · Page 19
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

177 Lu-Labeled Phosphoramidate-Based PSMA Inhibitors: The Effect of an Albumin Binder on Biodistribution and Therapeutic Efficacy in Prostate Tumor-Bearing Mice

Prostate-specific membrane antigen (PSMA) continues to be an active biomarker for small-molecule PSMA-targeted imaging and therapeutic agents for prostate cancer and various non-prostatic tumors that are characterized by PSMA expression on their neovasculature. One of the challenges for small-molecule PSMA inhibitors with respect to delivering therapeutic payloads is their rapid renal clearance. In order to overcome this pharmacokinetic challenge, we outfitted a 177 Lu-labeled phosphoramidate-based PSMA inhibitor (CTT1298) with an albumin-binding motif (CTT1403) and compared its in vivo performance with that of an analogous compound lacking the albumin-binding motif (CTT1401). The radiolabeling of CTT1401 and CTT1403 was achieved using click chemistry to connect 177 Lu-DOTA-N3 to the dibenzocyclooctyne (DBCO)-bearing CTT1298 inhibitor cores. A direct comparison in vitro and in vivo performance was made for CTT1401 and CTT1403; the specificity and efficacy by means of cellular uptake and internalization, biodistribution, and therapeutic efficacy were determined for both compounds. And while both compounds displayed excellent uptake and rapid internalization in PSMA+ PC3-PIP cells, the albumin binding moiety in CTT1403 conferred clear advantages to the PSMA-inhibitor scaffold including increased circulating half-life and prostate tumor uptake that continued to increase up to 168 h post-injection. This then increased tumor uptake translated into superior therapeutic efficacy of CTT1403 in PSMA+ PC3-PIP human xenograft tumors.

177Lu↗
DOE OSTI2021

Partial connectomes of labeled dopaminergic circuits reveal non-synaptic communication and axonal remodeling after exposure to cocaine

Dopaminergic (DA) neurons exert profound influences on behavior including addiction. However, how DA axons communicate with target neurons and how those communications change with drug exposure remains poorly understood. We leverage cell type-specific labeling with large volume serial electron microscopy to detail DA connections in the nucleus accumbens (NAc) of the mouse (Mus musculus) before and after exposure to cocaine. We find that individual DA axons contain different varicosity types based on their vesicle contents. Spatially ordering along individual axons further suggests that varicosity types are non-randomly organized. DA axon varicosities rarely make specific synapses (<2%, 6/410), but instead are more likely to form spinule-like structures (15%, 61/410) with neighboring neurons. Days after a brief exposure to cocaine, DA axons were extensively branched relative to controls, formed blind-ended ‘bulbs’ filled with mitochondria, and were surrounded by elaborated glia. Finally, mitochondrial lengths increased by ~2.2 times relative to control only in DA axons and NAc spiny dendrites after cocaine exposure. We conclude that DA axonal transmission is unlikely to be mediated via classical synapses in the NAc and that the major locus of anatomical plasticity of DA circuits after exposure to cocaine are large-scale axonal re-arrangements with correlated changes in mitochondria.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Data supporting manuscript from L. Sheneman, G. Stephanopoulos, A.E. Vasdekis titled "Deep learning classification of lipid droplets in quantitative phase images" as currently under review at PLOS ONE. This includes: 1) raw and binary labeled Quantitative Phase Images (QPI) of Y. lipolytica cells used in the analyses described within the manuscript. 2) various derived data including classifier scores, etc.

Data supporting manuscript from L. Sheneman, G. Stephanopoulos, A.E. Vasdekis titled "Deep learning classification of lipid droplets in quantitative phase images" as currently under review at PLOS ONE. This includes: 1) raw and binary labeled Quantitative Phase Images (QPI) of Y. lipolytica cells used in the analyses described within the manuscript. 2) various derived data including classifier scores, etc.

ANN↗
DOE OSTI2013

Labeled ALPHA4BETA2 ligands and methods therefor

Contemplated compositions and methods are employed to bind in vitro and in vivo to an .alpha.4.beta.2 nicotinic acetylcholine receptor in a highly selective manner. Where such compounds are labeled, compositions and methods employing such compounds can be used for PET and SPECT analysis. Alternatively, and/or additionally contemplated compounds can be used as antagonists, partial agonists or agonists in the treatment of diseases or conditions associated with .alpha.4.beta..beta.2 dysfunction.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Using phylogenetic probes for quantification of stable isotope labeling and microbial community analysis

Herein is described methods for a high-sensitivity means to measure the incorporation of stable isotope labeled substrates into RNA following stable isotope probing experiments (SIP). RNA is hybridized to a set of probes such as phylogenetic microarrays and isotope incorporation is quantified such as by secondary ion mass spectrometer imaging (NanoSIMS).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Rapid and label-free procedure for microbial community screening and profiling

Methods are described herein and termed Microbial Community Screening and Profiling (MCSP) for multi-dimensional analysis and non-destructive and label-free detection and analysis, which allow for complementary analytical techniques to be performed on the same sample for such multidimensional analysis.

Birarda, Giovanni↗
DOE OSTI2017

Stability of Residual Oxides in Oxide-Derived Copper Catalysts for Electrochemical CO 2 Reduction Investigated with 18 O Labeling

Oxide-derived (OD) Cu catalysts possess high selectivity towards the formation of multi-carbon products (C 2 /C 3 ) for aqueous electrochemical CO 2 reduction (CO 2 R). It has been proposed that a large fraction of the initial oxide can be surprisingly resistant to reduction, and these residual oxides play a crucial catalytic role. The stability of residual oxides was investigated by synthesizing 18 O-enriched OD Cu catalysts and testing them for CO 2 R. These catalysts maintain a high selectivity towards C 2 /C 3 products (ca. 60 %) for up to 5 h in 0.1 m KHCO 3 at -1.0 V vs. RHE. Yet, secondary-ion mass spectrometry measurements show that only a small fraction (<1 %) of the original 18 O content remains, showing that residual oxides are not present in significant amounts during CO 2 R. Moreover, we show that OD Cu can reoxidize rapidly, which could compromise the accuracy of ex situ methods for determining the true oxygen content.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Fluorescent labelling of intestinal epithelial cells reveals independent long-lived intestinal stem cells in a crypt

Highlights: • Lentivirus mixed with Matrigel enables direct infection of intestinal organoids. • Our original approach allows the marking of a single stem cell in a crypt. • Time-lapse imaging shows the dynamics of a single stem cell. • Our lentivirus transgene system demonstrates plural long-lived stem cells in a crypt. - Abstract: Background and aims: The dynamics of intestinal stem cells are crucial for regulation of intestinal function and maintenance. Although crypt stem cells have been identified in the intestine by genetic marking methods, identification of plural crypt stem cells has not yet been achieved as they are visualised in the same colour. Methods: Intestinal organoids were transferred into Matrigel® mixed with lentivirus encoding mCherry. The dynamics of mCherry-positive cells was analysed using time-lapse imaging, and the localisation of mCherry-positive cells was analysed using 3D immunofluorescence. Results: We established an original method for the introduction of a transgene into an organoid generated from mouse small intestine that resulted in continuous fluorescence of the mCherry protein in a portion of organoid cells. Three-dimensional analysis using confocal microscopy showed a single mCherry-positive cell in an organoid crypt that had been cultured for >1 year, which suggested the presence of long-lived mCherry-positive and -negative stem cells in the same crypt. Moreover, a single mCherry-positive stem cell in a crypt gave rise to both crypt base columnar cells and transit amplifying cells. Each mCherry-positive and -negative cell contributed to the generation of organoids. Conclusions: The use of our original lentiviral transgene system to mark individual organoid crypt stem cells showed that long-lived plural crypt stem cells might independently serve as intestinal epithelial cells, resulting in the formation of a completely functional villus.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Silica coating of luminescent quantum dots prepared in aqueous media for cellular labeling

Graphical abstract: A facile route based on modified Stöber method was used for the synthesis of silica coated QDs (QD@SiO{sub 2}) starting from aqueously prepared CdTe/CdS QDs. The resultant QD@SiO{sub 2} exhibited a significant increase in emission efficiency compared with that of the initial QDs, along with a small size (∼5 nm in diameter), great stability and low cytotoxicity, which makes it a good candidate as robust biomarker. - Highlights: • We present a facile modified Stöber method to prepare highly luminescent QD@SiO{sub 2}. • The PL efficiency of QDs increases significantly after silica coating. • QD@SiO{sub 2} exhibits small size (∼5 nm) and great dispersibility in aqueous solution. • QD@SiO{sub 2} presents extraordinary photo and colloidal stability. • The silica shell eliminates QD cytotoxicity, providing the access of bioconjugation. - Abstract: Silica coating is an effective approach for rendering luminescent quantum dots (QDs) with water dispersibility and biocompatibility. However, it is still challenging to prepare silica-coated QDs (QD@SiO{sub 2}) with high emission efficiency, small size and great stability in favor for bioapplication. Herein, we reported a modified Stöber method for silica coating of aqueously-prepared CdTe/CdS QDs. With the coexistence of Cd{sup 2+} and thioglycolic acid (TGA), a thin silica shell was formed around QDs by the hydrolysis of tetraethyl orthosilicate (TEOS). The resultant QD@SiO{sub 2} with a small size (∼5 nm in diameter) exhibits significantly higher emission efficiencies than that of the initial QDs. Also, QD@SiO{sub 2} has extraordinary photo and colloidal stability (pH range of 5–13, 4.0 M NaCl solution). Protected by the silica shell, the cytotoxicity of QDs could be reduced. Moreover, the QD@SiO{sub 2} conjugated with folic acid (FA) presents high specific binding toward receptor-positive HeLa cells over receptor-negative A549 cells.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Ultrasound assisted sonochemically engineered effective red luminescent labeling agent for high resolution visualization of latent fingerprints

Highlights: • BaTiO{sub 3}:Eu{sup 3+} NPs were prepared by facile bio-template assisted sonochemical route. • The obtained samples displayed superstructures of various regular morphological shapes. • The optimized product was used for forensic and anti-counterfeiting applications. • CIE, CCT studies indicate the present phosphor was highly useful in LED’s. - Abstract: Nanoscience and technology finds wide range of benefits in the area of surface based science due to its nano size and high surface area. This offers new potentials in surface-based science comprising latent fingerprint (LFP) and to develop luminescent ink for anti-counterfeiting applications. Due to high backward hindrance, low sensitivity, complicated setup, and poor universality of traditionally developed techniques were main drawbacks for the visualization of LFPs. To overcome these problems, we explored the superstructures (SS) of europium ions doped BaTiO{sub 3} nanophosphors (NPs) prepared via sonochemical route with bio-template as surfactant for the detection of LFPs and as an anti-counterfeiting ink. The morphologies of SS were highly dependent on the concentration of Aloe vera (A.V.) gel as well as ultrasound irradiation time. The obtained SS displayed pure red emission which corresponds to the {sup 5}D{sub 0} → {sup 7}F{sub J} transitions of Eu{sup 3+} ions under UV light. The results clearly evident that the optimized BaTiO{sub 3}:Eu{sup 3+} NPs will create a new prospect for research in LFPs visualization and anti-counterfeiting technology.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Facile synthesis of the nitrogen-doped graphene quantum dots at low temperature for cellular labeling

Highlights: • The N-GQDs are prepared via a facile stirring method on a magnetic stirrer at low temperature. • The N-GQDs exhibit outstanding biocompatibility in the live HeLa cells for biological applications. • The live cells keep a 100% survival rate in the high N-GQDs concentration of 200 μg mL{sup −1} for 48 h. - Abstract: A facile one-step approach is developed for the large-scale synthesis of nitrogen doped graphene quantum dot (N-GQDs) at low temperature by using citric acid (CA) as the precursor. The emission wavelength of the N-GQDs is nearly excitation-dependent, which may mirror the effects from particles of different sizes and distribution of different emissive sites on nanoparticles. Moreover, the products are then tested with live Hela cells for the extraordinary biocompatibility. The cellular viability is remained to be 100% even after a 48 h exposure with the high N-GQDs concentration of 200 μg mL{sup −1} and this survival rate is really much higher than that have been reported previously. The as-prepared N-GQDs with negligible inherent toxicity exhibit excellent biological applications such as bio-imaging and cell tracking.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

SU-E-I-65: Estimation of Tagging Efficiency in Pseudo-Continuous Arterial Spin Labeling (pCASL) MRI

Purpose: pCASL was recommended as a potent approach for absolute cerebral blood flow (CBF) quantification in clinical practice. However, uncertainties of tagging efficiency in pCASL remain an issue. This study aimed to estimate tagging efficiency by using short quantitative pulsed ASL scan (FAIR-QUIPSSII) and compare resultant CBF values with those calibrated by using 2D Phase Contrast (PC) MRI. Methods: Fourteen normal volunteers participated in this study. All images, including whole brain (WB) pCASL, WB FAIR-QUIPSSII and single-slice 2D PC, were collected on a 3T clinical MRI scanner with a 8-channel head coil. DeltaM map was calculated by averaging the subtraction of tag/control pairs in pCASL and FAIR-QUIPSSII images and used for CBF calculation. Tagging efficiency was then calculated by the ratio of mean gray matter CBF obtained from pCASL and FAIR-QUIPSSII. For comparison, tagging efficiency was also estimated with 2D PC, a previously established method, by contrast WB CBF in pCASL and 2D PC. Feasibility of estimation from a short FAIR-QUIPSSII scan was evaluated by number of averages required for obtaining a stable deltaM value. Setting deltaM calculated by maximum number of averaging (50 pairs) as reference, stable results were defined within ±10% variation. Results: Tagging efficiencies obtained by 2D PC MRI (0.732±0.092) were significantly lower than which obtained by FAIRQUIPPSSII (0.846±0.097) (P<0.05). Feasibility results revealed that four pairs of images in FAIR-QUIPPSSII scan were sufficient to obtain a robust calibration of less than 10% differences from using 50 pairs. Conclusion: This study found that reliable estimation of tagging efficiency could be obtained by a few pairs of FAIR-QUIPSSII images, which suggested that calibration scan in a short duration (within 30s) was feasible. Considering recent reports concerning variability of PC MRI-based calibration, this study proposed an effective alternative for CBF quantification with pCASL.

60 APPLIED LIFE SCIENCES↗