The reaction N(S) + NO(XΠ) → O(P) + N(XΣ+g) plays a pivotal role in the conversion of atomic to molecular nitrogen in dense interstellar clouds and in the atmosphere. Here we report a joint experimental and computational investigation of the N + NO reaction with the aim of providing improved constraints on its low temperature reactivity. Thermal rates were measured over the 50 to 296 K range in a continuous supersonic flow reactor coupled with pulsed laser photolysis and laser induced fluorescence for the production and detection of N(S) atoms, respectively. With decreasing temperature, the experimentally measured reaction rate was found to monotonously increase up to a value of (6.6 ± 1.3) × 10 cm s at 50 K. To confirm this finding, quasi-classical trajectory simulations were carried out on a previously validated, full-dimensional potential energy surface (PES). However, around 50 K the computed rates decreased which required re-evaluation of the reactive PES in the long-range part due to a small spurious barrier with a height of ∼40 K in the entrance channel. By exploring different correction schemes the measured thermal rates can be adequately reproduced, displaying a clear negative temperature dependence over the entire temperature range. The possible astrochemical implications of an increased reaction rate at low temperature are also discussed.
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http://dx.doi.org/10.1039/d3cp00584d | DOI Listing |
Pharmaceutics
January 2025
Department of Pharmaceutics and Medicinal Chemistry, University of the Pacific, Stockton, CA 95211, USA.
Micelles, liposomes, and solid lipid nanoparticles (SLNs) are promising drug delivery vehicles; however, poor aqueous stability requires post-processing drying methods for maintaining long-term stability. The objective of this study was to compare the potential of lipid-based micelles, liposomes, and SLNs for producing stable re-dispersible spray-dried powders with trehalose or a combination of trehalose and L-leucine. This study provides novel insights into the implementation of spray drying as a technique to enhance long-term stability for these lipid-based nanocarriers.
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January 2025
Shapotou Desert Research and Experimental Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 320 Donggang West Road, Lanzhou 730000, China.
Turcz. is a winter annual species of the Asteraceae family, distributed in sandy areas of northern China, and is crucial for wind avoidance and sand fixation. To understand the inter- and intra-annual population dynamics of in its cold desert habitats, we conducted long- and short-term demographic studies to investigate the timing of germination, seedling survival, soil seed bank and seed longevity of natural populations on the fringe of the Tengger Desert.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Department of Plant and Soil Sciences, University of Pretoria, Hatfield, Pretoria P.O. Box X20, South Africa.
The global rise in temperatures due to climate change has made it difficult even for specialised desert-adapted plant species to survive on sandy desert soils. Two of Namibia's iconic desert-adapted plant species, and the quiver tree , have recently been shown to be under threat because of climate change. In the current study, three ecologically important Namibian milk bushes were evaluated for their climate change response.
View Article and Find Full Text PDFPlants (Basel)
January 2025
College of Life Sciences, Shihezi University, Shihezi 832000, China.
Plants have large amounts of the late embryogenesis abundant protein (LEA) family of proteins, which is involved in osmotic regulation. The Korla Pear () is an uncommon pear species that thrives in Xinjiang and can survive below-freezing conditions. We found that the gene was more expressed after cold treatment by looking at the transcriptome data of the Korla Pear.
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January 2025
College of Mechanical and Electrical Engineering, Qingdao University, Qingdao 266071, China.
Currently, in the domestic practice of retreading tires using vulcanization tanks, some tanks exhibit uneven temperature distributions leading to low retreading success rates. To address that, this paper simulated the temperature and velocity fields during the heating process of vulcanization tanks for waste tire retreading. The results indicated that a higher heating power reduces the time required for the vulcanizing agent to reach the vulcanization condition, but it also increases the difference in tire temperature in the tank, with a severely uneven distribution of the temperature field.
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