The derivation of equations of state for fluid phases of a partially ionized gas or plasma is addressed from a fundamental point of view. The results of the Thomas-Fermi model always yield pressures which are less than or equal to that of an ideal Fermi gas. On the other hand, the spherical cellular model shows significant "overpressure" relative to the ideal Fermi gas in certain regions of low density and low temperature. This effect is studied in considerable detail. A nonthermodynamic region, more or less overlapping the regions of overpressure, is found. It is characterized by a negative specific heat at constant volume. An independent electron model within a Z -electron cell is employed. The inadequacy of the wave function in the low-density, low-temperature nonthermodynamic region is shown to be the cause of this overpressure. Numerical examples of the theory for several elements (Li, N, Al, K, and Er) are reported. These results reduce in various limits of temperature and density to the expected behavior, except in the aforementioned region.
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http://dx.doi.org/10.1103/PhysRevE.77.031120 | DOI Listing |
Anal Chem
January 2025
Department of Analytical Chemistry, Faculty of Science, Palacký University Olomouc, 17. Listopadu 12, 77146 Olomouc, Czech Republic.
A novel remote deep ultraviolet laser ablation inlet connected to a dual electrospray ionization-atmospheric pressure chemical ionization (rDUVLAESCI) source is presented. This system allows for the simultaneous and spatial acquisition of mass spectrometry (MS) data for organic molecules with diverse polarities and molecular weights. Deep 193 nm UV laser ablation was used to sample analytes from dried spots for molecular MS analysis precisely.
View Article and Find Full Text PDFCurr Gene Ther
January 2025
Department of Chemistry and Environmental Sciences, IBILCE, São Paulo State University - UNESP, São José do Rio Preto, São Paulo, Brazil.
Introduction: The clinical translation of chitosan-based formulations for siRNA delivery has been partially limited by their poor stability/solubility at physiological conditions, although they have good biocompatibility and cost-effectiveness.
Method: In this study, the chitosan was O-substituted with diisopropylethylamine (DIPEA) groups, which improved its solubility at pH 7.4 by increasing the degree of ionization and enhanced the ability of chitosan to load siRNA at very low amine/phosphate (N/P) ratios.
Chem Sci
December 2024
Materials Discovery Laboratory (MaD Lab), Department of Chemistry, Oregon State University Corvallis OR 97331 USA
The reaction between molybdenum(ii) acetate and 5-aminoisophthalic acid (HIso-NH) afforded [MoO(μ-O)(Iso-NH)], a novel molybdenum(v) metal-organic polyhedron (MOP) with a triangular antiprismatic shape stabilized by intramolecular N-H⋯O hydrogen bonds. The synthesis conditions, particularly the choice of solvent and reaction time, led to the precipitation of the Mo(v)-MOP in five distinct crystalline forms. These forms vary in their packing arrangements, co-crystallized solvent molecules, and counter-cations, with three phases containing dimethylammonium (dma) and the other two containing diethylammonium (dea).
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Department of Chemistry and Chemical Biology, Indiana University─Indianapolis, Indianapolis, Indiana 46202, United States.
Electrospray ionization mass spectrometry (ESI-MS) can retain intact protein structures, but details about partially folded and unfolded protein structures during and after introduction to the gas phase are elusive. Here we use ESI-MS with chemical cross-linkers to compare denatured cytochrome structures in both solution and gas phases. Solution phase cross-linking prior to ESI captures solution phase structures, while gas phase cross-linking through ion/ion reactions in the trap cell captures gas phase structures.
View Article and Find Full Text PDFNature
January 2025
Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
Pre-eclampsia is a placental disorder that affects 3-5% of all pregnancies and is a leading cause of maternal and fetal morbidity worldwide. With no drug available to slow disease progression, engineering ionizable lipid nanoparticles (LNPs) for extrahepatic messenger RNA (mRNA) delivery to the placenta is an attractive therapeutic option for pre-eclampsia. Here we use high-throughput screening to evaluate a library of 98 LNP formulations in vivo and identify a placenta-tropic LNP (LNP 55) that mediates more than 100-fold greater mRNA delivery to the placenta in pregnant mice than a formulation based on the Food and Drug Administration-approved Onpattro LNP (DLin-MC3-DMA).
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