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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 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Membrane‐acting biomimetic peptoids against visceral leishmaniasis

Visceral leishmaniasis (VL) is among the most neglected tropical diseases in the world. Drug cell permeability is essential for killing the intracellular residing parasites responsible for VL, making cell‐permeating peptides a logical choice to address VL. Unfortunately, the limited biological stability of peptides restricts their usage. Sequence‐specific oligo‐ N ‐substituted glycines (‘peptoids’) are a class of peptide mimics that offers an excellent alternative to peptides in terms of ease of synthesis and good biostability. We tested peptoids against the parasite Leishmania donovani in both forms, that is, intracellular amastigotes and promastigotes. N ‐alkyl hydrophobic chain addition (lipidation) and bromination of oligopeptoids yielded compounds with good antileishmanial activity against both forms, showing the promise of these antiparasitic peptoids as potential drug candidates to treat VL.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

A Vitrimer Acts as a Compatibilizer for Polyethylene and Polypropylene Blends

Abstract Polymer compatibilization plays a critical role in achieving polymer blends with favorable mechanical properties and enabling efficient recycling of mixed plastic wastes. Nonetheless, traditional compatibilization methods often require tailored designs based on the specific chemical compositions of the blends. In this study, we propose a new approach for compatibilizing polymer blends using a dynamically crosslinked polymer network, known as vitrimers. By adding a relatively small amount (1–5 w/w%) of a vitrimer made of siloxane‐crosslinked high‐density polyethylene (HDPE), we successfully compatibilized unmodified HDPE and isotactic polypropylene (iPP). The vitrimer‐compatibilized blend exhibited enhanced elongation at break (120 %) and smaller iPP domain sizes (0.4 μm) compared to the control blend (22 % elongation at break, 0.9 μm iPP droplet size). Moreover, the vitrimer‐compatibilized blend showed significantly improved microphase stability during annealing at 180 °C. This straightforward method shows promise for applications across various polymer blend systems.

Yokoyama, Kosuke↗
DOE OSTI2024

A Vitrimer Acts as a Compatibilizer for Polyethylene and Polypropylene Blends

Polymer compatibilization plays a critical role in achieving polymer blends with favorable mechanical properties and enabling efficient recycling of mixed plastic wastes. Nonetheless, traditional compatibilization methods often require tailored designs based on the specific chemical compositions of the blends. In this study, we propose a new approach for compatibilizing polymer blends using a dynamically crosslinked polymer network, known as vitrimers. By adding a relatively small amount (1–5 w/w%) of a vitrimer made of siloxane‐crosslinked high‐density polyethylene (HDPE), we successfully compatibilized unmodified HDPE and isotactic polypropylene (iPP). The vitrimer‐compatibilized blend exhibited enhanced elongation at break (120 %) and smaller iPP domain sizes (0.4 μm) compared to the control blend (22 % elongation at break, 0.9 μm iPP droplet size). Moreover, the vitrimer‐compatibilized blend showed significantly improved microphase stability during annealing at 180 °C. This straightforward method shows promise for applications across various polymer blend systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Solvent Acts as the Referee in a Match‐Up Between Charged and Preorganized Receptors

The prevalence of anion-cation contacts in biomolecular recognition under aqueous conditions suggests that ionic interactions should dominate the binding of anions in solvents across both high and low polarities. Investigations of this idea using titrations in low polarity solvents are impaired by interferences from ion pairing that prevent a clear picture of binding. To address this limitation and test the impact of ion-ion interactions across multiple solvents, we quantified chloride binding to a cationic receptor after accounting for ion pairing. In these studies, we created a chelate receptor using aryl-triazole CH donors and a quinolinium unit that directs its cationic methyl inside the binding pocket. In low-polarity dichloromethane, the 1 : 1 complex (log K 1 : 1 ~ 7.3) is more stable than neutral chelates, but fortuitously comparable to a preorganized macrocycle (log K 1 : 1 ~ 6.9). Polar acetonitrile and DMSO diminish stabilities of the charged receptor (log K 1 : 1 ~ 3.7 and 1.9) but surprisingly 100-fold more than the macrocycle. While both receptors lose stability by dielectric screening of electrostatic stability, the cationic receptor also pays additional costs of organization. Thus even though the charged receptor has stronger binding in apolar solvents, the uncharged receptor has more anion affinity in polar solvents.

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

Design of Highly Potent, Dual-Acting and Central-Nervous-System-Penetrating HIV-1 Protease Inhibitors with Excellent Potency against Multidrug-Resistant HIV-1 Variants

Herein we report the design, synthesis, X–ray structural, and biological studies of an exceptionally potent HIV–1 protease inhibitor, compound 5 ((3S,7aS,8S)–hexahydro–4H–3,5–methanofuro[2,3–b]pyran–8–yl ((2S,3R)–4–((2–(cyclopropylamino)–N–isobutylbenzo[d]thiazole)–6–sulfonamido)–1–(3,5–difluorophenyl)–3–hydroxybutan–2–yl)carbamate). Using structure–based design, we incorporated an unprecedented 6–5–5–ring–fused crown–like tetrahydropyranofuran as the P2–ligand, a cyclopropylaminobenzothiazole as the P2'–igand, and a 3,5–difluorophenylmethyl group as the P1–ligand. The resulting inhibitor 5 exhibited exceptional HIV–1 protease inhibitory and antiviral potency at the picomolar level. Furthermore, it displayed antiviral IC50 values in the picomolar range against a wide panel of highly multidrug–resistant HIV–1 variants. The inhibitor shows an extremely high genetic barrier against the emergence of drug…resistant variants. It also showed extremely potent inhibitory activity toward dimerization as well as favorable central nervous system penetration. Here, we determined a high–resolution X–ray crystal structure of the complex between inhibitor 5 and HIV–1 protease, which provides molecular insight into the unprecedented activity profiles observed.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

The study of the elementary acts of a reversible photochemical reaction generating quasistationary radio emission in a magnetic field

Constant coherent radio frequency radiation in the course of a reversible photochemical reaction of a 8-hydroxy-6-dibenzofuran—deuteromethanol system was detected and investigated. The observed effect is one of the few examples of the generation of stationary radio emission during a photoreaction and may have a practical application. The elementary stages and the mechanism of these photoreactions are presented.

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

Correction to: IL-39 acts as a friend to pancreatic cancer

The original version of this article unfortunately contained a mistake in the text of the entire article. The word “IL-39” should read as “meteorin-like protein”. This has been corrected with this correction.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2017

Transactive control of fast-acting demand response based on thermostatic loads in real-time retail electricity markets

Coordinated operation of distributed thermostatic loads such as heat pumps and air conditioners can reduce energy costs and prevents grid congestion, while maintaining room temperatures in the comfort range set by consumers. This paper furthers efforts towards enabling thermostatically controlled loads (TCLs) to participate in real-time retail electricity markets under a transactive control paradigm. An agent-based approach is used to develop an effective and low complexity demand response control scheme for TCLs. The proposed scheme adjusts aggregated thermostatic loads according to real-time grid conditions under both heating and cooling modes. Here, a case study is presented showing the method reduces consumer electricity costs by over 10% compared to uncoordinated operation.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2017

H 2 -optimal transactive control of electric power regulation from fast-acting demand response in the presence of high renewables

Here, this paper presents an H 2 -optimal power regulation scheme for balancing authorities to provide regulation services using both generation and load resources in the presence of a significant amount of intermittent renewable generation. The optimal controller is designed to minimize the loss of total economic surplus due to deviations from the schedule because of generation contingencies. The results show that the optimal controller outperforms the conventional ACE control policy by (1) providing faster return to the schedule under varying demand response levels, (2) reducing the cost of using reserve units for regulation services, and (3) minimizing deviations from the global surplus-maximizing schedule.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2010

C-type lectins do not act as functional receptors for filovirus entry into cells

Research highlights: {yields} Filovirus glycoprotein (GP) having a deficient receptor binding region were generated. {yields} Mutant GPs mediated virus entry less efficiently than wild-type GP. {yields} Mutant GPs bound to C-type lectins but not mediated entire steps of cellular entry. {yields} C-type lectins do not independently mediate filovirus entry into cells. {yields} Other molecule(s) are required for C-type lectin-mediated entry of filoviruses. -- Abstract: Cellular C-type lectins have been reported to facilitate filovirus infection by binding to glycans on filovirus glycoprotein (GP). However, it is not clearly known whether interaction between C-type lectins and GP mediates all the steps of virus entry (i.e., attachment, internalization, and membrane fusion). In this study, we generated vesicular stomatitis viruses pseudotyped with mutant GPs that have impaired structures of the putative receptor binding regions and thus reduced ability to infect the monkey kidney cells that are routinely used for virus propagation. We found that infectivities of viruses with the mutant GPs dropped in C-type lectin-expressing cells, parallel with those in the monkey kidney cells, whereas binding activities of these GPs to the C-type lectins were not correlated with the reduced infectivities. These results suggest that C-type lectin-mediated entry of filoviruses requires other cellular molecule(s) that may be involved in virion internalization or membrane fusion.

60 APPLIED LIFE SCIENCES↗