A kinetic theory of nucleation and growth of a evolving phase with a given stoichiometric composition in a multicomponent solid solution is developed. It is assumed naturally that the phase grows as a result of individual atom incorporation into the phase domain in a stoichiometric ratio. As it is shown, for the case of phase formation in a multicomponent system the basic kinetic equations, describing the nucleation-growth process, can be reduced formally to the respective expression derived for nucleation-growth processes in one-component systems. However, the effective diffusion coefficients and the effective supersaturation are expressed as nontrivial combinations of the thermodynamic and kinetic parameters of the different components involved in the phase formation process. In the determination of these properties, the theory is not restricted in its applicability to perfect solutions but extended to phase formation in real mixtures. Thus, the theory may be applied directly towards the interpretation of experimental data. In the present paper, particular attention is devoted to the analysis of the two stages of the overall transformation process: (1) the stage of quasi-steady-state nucleation and (2) the transient stage of coarsening. As the results of this analysis, the quasi-steady-state nucleation rate, the number of clusters formed via nucleation and growth, and the time evolution of the cluster size distributions are established. Moreover, estimates are given for the duration of the different stages of the transformation process.
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http://dx.doi.org/10.1103/PhysRevE.65.031506 | DOI Listing |
Plant Physiol Biochem
January 2025
Laboratory of Microbial Genetics, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India. Electronic address:
Nitric oxide synthases (NOSs) are heme-based monooxygenases that catalyze the NADPH-dependent oxidation of L-arginine to produce NO and L-citrulline. Over the past five years, the identification and characterization of NOS homologs in cyanobacteria have significantly advanced our understanding of these enzymes. However, the precise mechanisms through which NOS-derived NO influences nitrogen metabolism remain incompletely elucidated.
View Article and Find Full Text PDFJCO Precis Oncol
January 2025
Division of Hematology-Oncology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA.
Purpose: Fibroblast growth factor receptor 2 isoform IIIb (FGFR2b) protein overexpression is an emerging biomarker in gastric cancer and gastroesophageal junction cancer (GC). We assessed FGFR2b protein overexpression prevalence in nearly 3,800 tumor samples as part of the prescreening process for a global phase III study in patients with newly diagnosed advanced or metastatic GC.
Methods: As of June 28, 2024, 3,782 tumor samples from prescreened patients from 37 countries for the phase III FORTITUDE-101 trial (ClinicalTrials.
PLoS One
January 2025
Cardiovascular Center, Division of Cardiology, Korea University Guro Hospital, Seoul, Republic of Korea.
Background: The phase angle (PhA) in bioelectrical impedance analysis (BIA) reflects the cell membrane integrity or body fluid equilibrium. We examined how the PhA aligns with previously known markers of acute heart failure (HF) and assessed its value as a screening tool.
Methods: PhA was measured in 50 patients with HF and 20 non-HF controls along with the edema index (EI), another BIA parameter suggestive of edema.
Proc Natl Acad Sci U S A
January 2025
Yusuf Hamied Department of Chemistry, Centre for Misfolding Diseases, University of Cambridge, Cambridge CB2 1EW, United Kingdom.
The onset and development of Alzheimer's disease is linked to the accumulation of pathological aggregates formed from the normally monomeric amyloid-β peptide within the central nervous system. These Aβ aggregates are increasingly successfully targeted with clinical therapies at later stages of the disease, but the fundamental molecular steps in early stage disease that trigger the initial nucleation event leading to the conversion of monomeric Aβ peptide into pathological aggregates remain unknown. Here, we show that the Aβ peptide can form biomolecular condensates on lipid bilayers both in molecular assays and in living cells.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Sports Medicine of the Second Affiliated Hospital, and Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou 311113, China.
Joining heterogeneous materials in engineered structures remains a significant challenge due to stress concentration at interfaces, which often leads to unexpected failures. Investigating the complex, multiscale-graded structures found in animal tissue provides valuable insights that can help address this challenge. The human meniscus root-bone interface is an exemplary model, renowned for its exceptional fatigue resistance, toughness, and interfacial adhesion properties throughout its lifespan.
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