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Protein storage vacuoles (PSVs) are unique organelles that accumulate storage proteins in plant seeds. Although morphological evidence points to the existence of multiple PSV-trafficking pathways for storage protein targeting, the molecular mechanisms that regulate these processes remain mostly unknown. Here, we report the functional characterization of the rice (Oryza sativa) glutelin precursor accumulation7 (gpa7) mutant, which over-accumulates 57-kDa glutelin precursors in dry seeds. Cytological and immunocytochemistry studies revealed that the gpa7 mutant exhibits abnormal accumulation of storage prevacuolar compartment-like structures, accompanied by the partial mistargeting of glutelins to the extracellular space. The gpa7 mutant was altered in the CCZ1 locus, which encodes the rice homolog of Arabidopsis (Arabidopsis thaliana) CALCIUM CAFFEINE ZINC SENSITIVITY1a (CCZ1a) and CCZ1b. Biochemical evidence showed that rice CCZ1 interacts with MONENSIN SENSITIVITY1 (MON1) and that these proteins function together as the Rat brain 5 (Rab5) effector and the Rab7 guanine nucleotide exchange factor (GEF). Notably, loss of CCZ1 function promoted the endosomal localization of vacuolar protein sorting-associated protein 9 (VPS9), which is the GEF for Rab5 in plants. Together, our results indicate that the MON1–CCZ1 complex is involved in post-Golgi trafficking of rice storage protein through a Rab5- and Rab7-dependent pathway.

Organoselenium compounds, due to their high structural diversity, special function, and biological activities, have drawn attention in synthetic chemistry. Herein, a novel example of chiral N,N′-di...

Catalytic enantioselective [2,3] Stevens and Sommelet-Hauser rearrangements of α-diazo pyrazoleamides with sulfides were achieved by utilizing chiral N,N'-dioxide/nickel(II ) complex catalysts. These rearrangements proceeded well under mild reaction conditions, providing rapid and facile access to a series of functionalized 1,6-dicarbonyls or sulfane-substituted phenylacetates with high to excellent enantioselectivities. The catalytic system shows excellent stereocontrol, discriminating between the heterotopic lone pairs of sulfur and controlling both the 1,3-proton transfer and the [2,3]-σ rearrangement.

The ratio of unconfined compressive strength to tensile strength (UCS/T) is a fundamental mechanical characteristics of rock materials, and the macroscopic mechanical properties of rocks under compression and tension conditions are seriously affected by microcracks. In this study, the numerical samples with three different microcrack distribution morphology (triangular mesh microcrack distribution morphology (T-MDM), Voronoi mesh microcrack distribution morphology (V-MDM), uniform microcrack distribution morphology (U-MDM)) were established based on different geometric forms. The effects of microcrack distribution morphology, microcrack density, and microcrack-matrix bond strength ratio on the mechanical properties of rocks were investigated, and the influence of various factors on the compression-tensile strength ratio was further discussed. Results showed that the rock samples with regular microcrack distribution morphology (T-MDM and V-MDM) exhibited a more reasonable compression-tensile strength ratio than those with random microcrack distribution morphology (U-MDM), and microcrack density has a significant effect on compression-tensile strength ratio under low bond strength ratio. Further, when the microcrack-matrix bond strength ratio is within the range of 0.05–0.15, the compression-tensile strength ratio of rock is basically between 10 and 30. The research results can provide reference for the construction of microstructure in numerical model and the simulation of reasonable mechanical behavior of rock.

A chiral N,N' -dioxide-nickel(II) complex-catalyzed asymmetric amination reaction of 3-bromo-3-substituted oxindoles with anilines was developed. A series of alkyl or aryl 3-amino-indolinones with quaternary stereocenters were obtained in high yields with excellent ee values in one step (up to 99% yield, up to 96% ee). The method provided a readily route to optically active intermediates of 3-amino-2-oxindole-based bioactive compounds. Besides, a possible transition state model was proposed to elucidate the origin of the chirality induction based on the X-ray crystal structure of the catalyst and the adduct.

The secondary amine participating asymmetric reductive amination remains an unsolved problem in organic synthesis. Here we show for the first time that secondary amines are capable of effectively serving as N-sources in direct asymmetric reductive amination to afford corresponding tertiary chiral amines with the help of a selected additive set under mild conditions (0–25 °C). The applied chiral phosphoramidite ligands are readily prepared from BINOL and easily modified. Compared with common tertiary chiral amine synthetic methods, this procedure is much more concise and scalable, as exemplified by the facile synthesis of rivastigmine and N-methyl-1-phenylethanamine.

The detonation of a column charge and the damage process in a rock mass are simulated in this study by the particle flow code method. The expansion loading method and the dynamic boundary treatment method are established according to the discrete element mechanism. Mechanical parameters are calibrated on the basis of the Starfield superposition principle and the dynamic compensation method. Dynamic stiffness and microscopic parameters are used for numerical simulations. Numerical test results are consistent with lab experimental test results. The velocity attenuation law is compared with that of theoretical results, and the blasting crater action index is compared with that of field test results, to verify the rationality of the numerical explosion model of the column charge. The mechanism of the rock breaking process under column charge explosion is analyzed. Stress wave propagation, detonation wave propagation, and crack extension are investigated. The stress wave gradient law is obtained, and the effects of blasting rock breaking, crack extension, and explosion effect outside the blasting crater area are determined with different initiation modes. The research method can explain the blasting stress wave propagation law and describe the dynamical failure process in rock masses. This study can provide a reliable numerical analysis method for follow-up blasting research and offer practical guidance on engineering blasting.

From a microscopic perspective, the mechanical behavior of rocks can be well simulated by particle discrete element method. However, the ideal mechanical properties under macroscopic compression and tension conditions of the granular system require not only reasonable micro-parameters but also consider the mineral distribution in rock microstructure. In this study, the internal microstructure of granite was characterized based on digital images. The cellular automata method was used to construct a discrete element model of clustered particles, and a rapid and effective calibration method for rock microscopic parameters was established. Numerical results significantly relate with laboratory test results, and the microscopic mechanical parameters of the rock were rapidly predicted. Clustered discrete element model simulated the macroscopic mechanical behavior of the investigated rock by considering microscopic rock structure while ignoring particle shape. Results showed that bond strength ratio of the filler–matrix in the numerical sample can significantly affect the compressive–tensile strength ratio. Further, the internal mineral proportion and degree of mineral contact damage strongly influenced the macroscopic mechanical behavior of the investigated rock. Results of this study can provide basis for the construction of micro-scaled model and calibration of microscopic parameters for investigation of rock mechanical behavior.

Fractured seepage is an important factor affecting the interface stability of rock mass. It is closely related to fracture properties and hydraulic conditions. In this study, the law of seepage in a single fracture surface based on modified cubic law is described, and the three-dimensional discrete element method is used to simulate the dam foundation structure of the Capulin San Pablo (Costa Rica) hydropower station. The effect of construction joints and developed structure on dam stability is studied, and its permeability law and sliding stability are also evaluated. It is found that the hydraulic-mechanical coupling with strength reduction method in DEM is more appropriate to use to study the seepage-related problems of fractured rock mass, which considers practical conditions, such as the roughness of and the width of fracture. The strength reduction method provides a more accurate safety factor of dam when considering the deformation coordination with bedrocks. It is an important method with which to study the stability of seepage conditions in complex structures. The discrete method also provided an effective and reasonable way of determining seepage control measures.