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Biomedical magnesium alloys exhibit high specific strength, low density, proper elastic modulus, biodegradability, good biocompatibility and biomechanical compatibility, thus show extensive application perspective in bone fixation and cardiovascular stent.However, fast and nonuniform corrosion of magnesium alloys may easily cause the premature loss of mechanical integrity that restricts their clinical application in load bearing. In this paper, the research progress of magnesium alloys was systematically reviewed from the aspects of corrosion modes, the intrinsic and external factors affecting corrosion resistance, improvement of intrinsic corrosion resistance and surface modification, and the future development trend of corrosion resistance of biomedical magnesium alloys was prospected. On the one hand, the corrosion resistance of magnesium alloys can be improved by means such as low alloying, high purification and fine crystallization. On the other hand, reliable coatings are designed from the aspects of corrosion resistance, antibacterial and drug loading. In addition, corrosion media, flow field, stress and other in-body service factors should be considered comprehensively to study the corrosion degradation behavior and mechanism of magnesium alloy implanted devices.

Our study investigates the genetic mechanisms underlying the spotted leaf phenotype in rice, focusing on the spl43 mutant. This mutant is characterized by persistent reddish-brown leaf spots from the seedling stage to maturity, leading to extensive leaf necrosis. Using map-based cloning, we localized the responsible locus to a 330 Kb region on chromosome 2. We identified LOC_Os02g56000, named OsRPT5A, as the causative gene. A point mutation in OsRPT5A, substituting valine for glutamic acid, was identified as the critical factor for the phenotype. Functional complementation and the generation of CRISPR/Cas9-mediated knockout lines in the IR64 background confirmed the central role of OsRPT5A in controlling this trait. The qPCR results from different parts of the rice plant revealed that OsRPT5A is constitutively expressed across various tissues, with its subcellular localization unaffected by the mutation. Notably, we observed an abnormal accumulation of reactive oxygen species (ROS) in spl43 mutants by examining the physiological indexes of leaves, suggesting a disruption in the ROS system. Complementation studies indicated OsRPT5A's involvement in ROS homeostasis and catalase activity regulation. Moreover, the spl43 mutant exhibited enhanced resistance to Xanthomonas oryzae pv. oryzae (Xoo), highlighting OsRPT5A's role in rice pathogen resistance mechanisms. Overall, our results suggest that OsRPT5A plays a critical role in regulating ROS homeostasis and enhancing pathogen resistance in rice. [ABSTRACT FROM AUTHOR]

The red beds are widely distributed in Yunnan, Guizhou, Sichuan and Southeast Asia. This material is not suitable as subgrade filling due to seriously weathering and its softening characteristic after absorbing water. In the project of the section between Chengdu and Ya'an of Sichuan-Tibet Railway, the graded weakly weathered red-mudstone fragments was added to red beds subgrade fillers with specific proportion to improve size distribution and compactness of the material. The stress-strain characterization of improved red beds subgrade fillings has been obtained from laboratory test. A method of randomly generating fragment geometry model with concave convex polyhedron shape has been proposed. Based on the numerical compression model established by PFC3D, the proportion of different strong force chains during loading and probability density distribution at the peak intensity have been studied. The results show that the improved red beds subgrade fillings with the stone content of 50% performs better mechanically with good deformation characteristics, and its unconfined compressive strength is 421.9 kPa. The fragments form super chains easily by friction under bond strength of red clay and that strengthens the system. The mechanical properties degree of improved red beds subgrade fillers follows the order of the stone content 50%> 40%> 60%. Therefore, it is recommended to add 50% of weakly weathered red-mudstone fragment as the subgrade fillings when improving the red bed clay of the Sichuan-Tibet Railway.

A gravitropism-deficient mutant M96 was isolated from a mutant bank, generated by ethyl methane sulfonate (EMS) mutagenesis of indica rice accession ZJ100. The mutant was characterized as prostrate growth at the beginning of germination, and the prostrate growth phenotype ran through the whole life duration. Tiller angle and tiller number of M96 increased significantly in comparison with the wild type. Tissue section observation analysis indicated that asymmetric stem growth around the second node occurred in M96. Genetic analysis and gene mapping showed that M96 was controlled by a single recessive nuclear gene, tentatively termed as gravitropism-deficient M96 (gdM96), which was mapped to a region of 506 kb flanked by markers RM5960 and InDel8 on the long arm of chromosome 11. Sequencing analysis of the open reading frames in this region revealed a nucleotide substitution from G to T in the third exon of LOC_Os11g29840. Additionally, real-time fluorescence quantitative PCR analysis showed that the expression level of LOC_Os11g29840 in the stems was much higher than in the roots and leaves in M96. Furthermore, the expression level was more than four times in M96 stem than in the wild type stem. Our results suggested that the mutant gene was likely a new allele to the reported gene LAZY1. Isolation of this new allele would facilitate the further characterization of LAZY1.

The accumulation of pigments affects the color of rice hulls while only limited information is known about its underlying mechanisms. In the present study, a rice brown hull 6 (bh6) mutant was isolated from an ethane methyl sulfonate (EMS)-induced IR64 mutant bank. Brown pigments started to accumulate in bh6 rice hulls after heading and reached a higher level in mature seeds. Some major agronomic traits including panicle length and 1000-grain weight in bh6 were significantly lower than those in its corresponding wild type IR64, while other agronomic traits such as plant height, growth duration and seed-setting rate were largely similar between the two genotypes. The analysis of pigment content showed that the contents of total flavonoids and anthocyanin in bh6 hulls were significantly higher than those in IR64 hulls. Our results showed that the brown hull phenotype in bh6 was controlled by a single recessive gene which locates on the long arm of chromosome 9. Sequencing analysis detected a single base substitution (G/A) at position 1013 of the candidate gene (LOC_Os09g12150) encoding an F-box domain-containing protein (FBX310). Functional complementation experiment using the wild type allele can rescue the phenotype in bh6. Thus, we named this mutated gene as OsFBX310bh6, an allele of OsFBX310 functioning as an inhibitor of brown hull. The isolation of OsFBX310bh6 and its wild type allele can provide useful experimental materials and will facilitate the studies on revealing the mechanisms of flavonoid metabolism in monocot plants.

We present a multiplane algorithm for three-dimensional uniform illumination. The large-diameter diffractive optical element simulated by this algorithm homogeneously concentrates more than 86.5% of the incident energy into a 200 [micro]m length of columnar space around the focal plane. The intensity profile in the whole space is nearly flat-top, and the beam's quality measured by the root mean square is less than 20.6%. The algorithm is very useful if a great deal of tolerance is required for the installation error of the optical system or if it is used for some particular application, such as uniform illumination on an incline plane. OCIS codes: 050.1970, 070.2580, 100.5070, 140.3300.