Increase In Axis Length Research Articles

Apparent permeability model for shale oil transport through elliptic nanopores considering wall-oil interaction

The shale oil transport mechanisms in inorganic matrix (iOM) and organic matrix (OM) nanopores are still not well understood, and the shape of nanopores is complex and diverse. Therefore, it is of critical importance to clarify the oil transport mechanisms in nanopores with different cross-sectional shapes. In this study, a model for oil transport is proposed to analyze the apparent permeability and flow enhancement based on the Hagen–Poiseuille equation. The proposed model takes into account the near-wall oil flow in iOM nanopores and the adsorbed oil flow in OM nanopores. In addition, the effects of different circular and elliptical cross-sections of nanopores and size of nanopores are considered. The proposed model is validated with the simulation data of non-equilibrium molecular dynamics and the Lattice Boltzmann method. The results indicate that: (1) the flow enhancement in iOM and OM nanopores first decreases rapidly and then stabilizes with an increasing length of semi-major axis a and semi-minor axis b because of the decreasing wall-oil interaction, and the apparent permeability of iOM increases as the axis a and axis b increase. When axis b is 2 nm, the permeability of OM increases with an increase in length of axis a, as length of axis b becomes larger, the permeability first decreases and then increases; (2) in iOM and OM nanopores, with a constant cross-sectional area, compared to nanopores with circle cross-sections, the flow enhancement becomes greater in nanopores with elliptical cross-sections, and the higher the ratio ω of the length of axis a to that of axis b, the greater the flow enhancement. The permeability of iOM nanopores decreases with an increasing ratio ω, while the permeability of OM nanopores first decreases and then increases. When the cross-sectional area is small, the permeability of OM nanopores increases with an increase in ratio ω, and as the cross-sectional area becomes greater, the permeability decreases with an increasing ratio ω. The proposed model demonstrates that elliptical cross-sections of nanopores can provide theoretical support for the development of shale oil reservoirs.

Functional characterization of naturally occurring wild soybean mutant (sg-5) lacking astringent saponins using whole genome sequencing approach

Triterpenoid saponins are one of the most highly accumulated groups of functional components in soybean (Glycine max) and the oxidative reactions during their biosynthesis are required for their aglycone diversity. Natural mutants of soyasaponins in wild soybean (Glycine soja) are valuable resources for establishing the soyasaponin biosynthesis pathway and breeding new soybean varieties. In this study, we investigated the genetic mechanism behind the absence of group A saponins in a Korean wild soybean mutant, CWS5095. Whole genome sequencing (WGS) of CWS5095 identified four point mutations [Val6 → Asp, Ile231 → Thr, His294 → Gln, and Arg376 → Lys] in CYP72A69 (Glyma15g39090), which oxygenate the C-21 position of soyasapogenol B or other intermediates to produce soyasapogenol A, leading to group A saponin production. An in vitro enzyme activity assay of single-sited mutated clones indicated that the Arg376 > Lys mutation (a highly conserved mutation based on a nucleotide change from G → A at the 1,127th position) may lead to loss of gene function in the sg-5 mutant. A very high normalized expression value of 377 reads per kilo base per million (RPKM) of Glyma15g39090 in the hypocotyl axis at the early maturation seed-development stage confirmed their abundant presence in seed hypocotyls. A molecular dynamics analysis of the Arg376 > Lys mutation based on the CYP3A4 (a human CYP450) protein structure found that it was responsible for the increase in axis length toward the heme (active site), which is critically important for biological activity and ligand binding. Our results provide important information on how to eradicate bitter and astringent saponins in soybean by utilizing the reported mutation in Glyma15g39090, and its importance for seed hypocotyl development based on transcript abundance.

Separation of Mechanisms Initiating Cell Division and Cell Expansion in Lettuce Seed Germination

After imbibition of water by seeds under favorable circumstances, the growth by which the embryo becomes a young seedling occurs by both expansion of cells originally present in the dormant embryo and rnitotic divisions resulting in an increase in cell number (15). Germination of lettuce seed has been of special interest to plant physiologists because it can be stimulated by gibberellins, kinetin, or light (8). sequence of the onset of cell division and elongation in germinating lettuce seed has been studied by Evenari et al (4), who found that the beginnings of mitotic activity and of cell elongation seemed to coincide in time. No mitotic activity was found in seeds prevented from germinating by withholding favorable light treatments. Their data suggested that, The start of mitoses, the beginning of cell elongation and the protrusion of the rootlet are correlated events during (4). Cell division and expansion do not begin simultaneously during germination of many other kinds of seeds. Cellular expansion precedes mitosis by many hours during germination of corn (14) or barley (2), and by several days in the broad bean (16). On the other hand, mitotic activity occurs several days before germination in pine seeds (5). Similarly, the number of cells per embryonic axis of after-ripening cherry seeds increased weeks before there was a detectable increase in axis length, which suggests that mitosis also precedes cell expansion in cherry seeds (11). Because division and expansion do not begin simultaneously during germination of many species of seeds, it is possible that lettuce might behave similarly under selected conditions. We therefore attempted to separate in time the inception of cell division from that of expansion during lettuce seed germination. results show not only that the beginning of mitotic activity can be made either to precede or to follow cell expansion, but also that mitotic activity can be completely separated from germination. These results are of general importance in understanding the mechanisms of germination for all types of seeds.