The phase structure and composition of a series of four alloys based on FeAl was investigated by means of scanning electron microscopy, X-ray diffraction and transmission electron microscopy. The materials were composed of Fe and Al with a fixed ratio of 3:1 alloyed with V, Cr and Ni at 8, 12, 15 and 20 at. % each (composition formula: Fe AlVCrNi). For 8% alloying, the material is single-phase D0. Furthermore, 12 and 15% alloying results in bcc-B2 phase separation on two length scales. Moreover, 20% alloying gives rise to the FeNiCrV σ phase supplemented by B2. These findings are discussed with respect to the results obtained via Calphad modeling using the TCHEA5 database and can serve in further improvement.
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http://dx.doi.org/10.3390/ma16155388 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Chinese Academy of Sciences Key Laboratory of Tropical Marine Bio Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, Guangdong Provincial Observation and Research Station for Coastal Upwelling Ecosystem, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China.
Rotation of the bacterial flagellum, the first identified biological rotary machine, is driven by its stator units. Knowledge gained about the function of stator units has increasingly led to studies of rotary complexes in different cellular pathways. Here, we report that a tetrameric PilZ family protein, FlgX, is a structural component underneath the stator units in the flagellar motor of .
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210.
The homo-dodecameric ring-shaped RNA binding attenuation protein (TRAP) from binds up to twelve tryptophan ligands (Trp) and becomes activated to bind a specific sequence in the 5' leader region of the operon mRNA, thereby downregulating biosynthesis of Trp. Thermodynamic measurements of Trp binding have revealed a range of cooperative behavior for different TRAP variants, even if the averaged apparent affinities for Trp have been found to be similar. Proximity between the ligand binding sites, and the ligand-coupled disorder-to-order transition has implicated nearest-neighbor interactions in cooperativity.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan.
Many bacteria swim in liquid or swarm on surface using the flagellum rotated by a motor driven by specific ion flow. The motor consists of the rotor and stator, and the stator converts the energy of ion flow to mechanical rotation. However, the ion pathway and the mechanism of stator rotation coupled with specific ion flow are still obscure.
View Article and Find Full Text PDFHum Reprod
January 2025
IRSD, Université de Toulouse, INSERM, INRAE, ENVT, Univ Toulouse III-Paul Sabatier (UPS), Toulouse, France.
Study Question: Does a human fallopian tube (HFT) organoid model offer a favourable apical environment for human sperm survival and motility?
Summary Answer: After differentiation, the apical compartment of a new HFT organoid model provides a favourable environment for sperm motility, which is better than commercial media.
What Is Known Already: HFTs are the site of major events that are crucial for achieving an ongoing pregnancy, such as gamete survival and competence, fertilization steps, and preimplantation embryo development. In order to better understand the tubal physiology and tubal factors involved in these reproductive functions, and to improve still suboptimal in vitro conditions for gamete preparation and embryo culture during IVF, we sought to develop an HFT organoid model from isolated adult stem cells to allow spermatozoa co-culture in the apical compartment.
Sci Adv
January 2025
Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, Hubei, China.
The proteasome degrades most superfluous and damaged proteins, and its decline is associated with many diseases. As the proteolytic unit, the 20 proteasome is assembled from 28 subunits assisted by chaperones PAC1/2/3/4 and POMP; then, it undergoes the maturation process, in which the proteolytic sites are activated and the assembly chaperones are cleared. However, mechanisms governing the maturation remain elusive.
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