The carbon rich phase diagrams of nickel-carbon nanoparticles, relevant to catalysis and catalytic chemical vapor deposition synthesis of carbon nanotubes, are calculated for system sizes up to about 3 nm (807 Ni atoms). A tight binding model for interatomic interactions drives the grand canonical Monte Carlo simulations used to locate solid, core shell and liquid stability domains, as a function of size, temperature, and carbon chemical potential or concentration. Melting is favored by carbon incorporation from the nanoparticle surface, resulting in a strong relative lowering of the eutectic temperature and a phase diagram topology different from the bulk one. This should lead to a better understanding of the nanotube growth mechanisms.
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http://dx.doi.org/10.1103/PhysRevLett.115.205502 | DOI Listing |
Nanoscale Adv
January 2025
Department of Chemical Engineering, The Ilse Katz Institute for Nanoscience and Technology, Ben-Gurion University of the Negev Beer Sheva 84105 Israel
Entropy-driven assembly of nematic liquid-crystal phases of cellulose nanocrystals (SCNCs) in aqueous suspensions results in the emergence of a cholesteric liquid crystalline phase (N* phase). We report that a solvated, non-adsorbing, highly branched natural polysaccharide, Gum Arabic (GA), strongly affects the assembly of the SCNCs and modifies the phase diagram: GA leads to significant crowding of the SCNC rods and induces a new liquid-liquid phase transition, where SCNC-rich and GA-rich droplets coexist. The solvated GA does not induce coagulation or gelation of the suspended SCNCs (at low concentrations of 1-3 wt% of GA).
View Article and Find Full Text PDFInt J Nanomedicine
January 2025
School of Pharmacy, Jiangxi Medical College, Nanchang University, Nanchang, 330006, People's Republic of China.
Purpose: To improve the oral absorption of relugolix (RLGL), which has low oral bioavailability due to its low solubility and being a substrate of P-glycoprotein (P-gp). A solid self-microemulsifying drug delivery system of relugolix (RLGL-S-SMEDDS) was prepared and evaluated in vitro and in vivo.
Methods: The composition of the solid self-microemulsifying drug delivery system (S-SMEDDS) was selected by solubility study and pseudo-ternary phase diagram, and further optimized by Design-Expert optimization design.
AAPS PharmSciTech
January 2025
School of Engineering and Sciences, Tecnologico de Monterrey, Campus Monterrey, Ave. Eugenio Garza Sada 2501 Sur, C.P. 64849, Monterrey, N.L., Mexico.
Metabolic syndrome (MS) has a high prevalence, with an estimated one-quarter of the world population affected by this pathological condition. Among the diseases of this syndrome are dysregulation of lipids, hypertension, and insulin resistance. Unfortunately, available drugs in the market used for treating MS, as almost 75% of all drugs, are highly insoluble, presenting a significant demand for strategies to increase their solubility.
View Article and Find Full Text PDFScience
January 2025
Department of Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
Phase diagrams and crystallography are standard tools for studying structural phase transitions, whereas acquiring kinetic information at the atomistic level has been considered essential but challenging. The η-to-θ phase transition of alumina is unidirectional in bulk and retains the crystal lattice orientation. We report a rare example of a statistical kinetics study showing that for nanoparticles on a bulk Al(OH) surface, this phase transition occurs nondeterministically through an ergodic equilibrium through the molten state, and the memory of the lattice orientation is lost in this process.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Beijing Computational Science Research Center, Beijing 100193, China.
In hybrid systems where nanowires are proximity-coupled with superconductors, the low-energy theory fails to determine the topological phase with Majorana fermion (MF) when the magnetic field or proximity coupling is much stronger. To overcome this limitation, we propose a holistic approach that defines MF by considering both the motion of electrons in the nanowire and the quasiparticle excitations in the superconductor. This approach transcends the constraints of low-energy theory and offers broad applicability.
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