Dipterocarpoideae species form the emergent layer of Asian rainforests. They are the indicator species for Asian rainforest distribution, but they are severely threatened. Here, to understand their ...adaptation and population decline, we assemble high-quality genomes of seven Dipterocarpoideae species including two autotetraploid species. We estimate the divergence time between Dipterocarpoideae and Malvaceae and within Dipterocarpoideae to be 108.2 (97.8‒118.2) and 88.4 (77.7‒102.9) million years ago, and we identify a whole genome duplication event preceding dipterocarp lineage diversification. We find several genes that showed a signature of selection, likely associated with the adaptation to Asian rainforests. By resequencing of two endangered species, we detect an expansion of effective population size after the last glacial period and a recent sharp decline coinciding with the history of local human activities. Our findings contribute to understanding the diversification and adaptation of dipterocarps and highlight anthropogenic disturbances as a major factor in their endangered status.
Although high-speed railway (HSR) subgrades in cold regions are filled with coarse-grained soil (CGS), they still undergo frost-heaving displacement. The liquid water–vapour migration mechanism can ...explain the frost-heaving process; therefore, the characteristics of liquid water–vapour migration in CGS are investigated in this study. The results show that in CGS, vapour migration is dominant under unidirectional freezing and dynamic loading. The water redistribution in the frozen zone and freezing front is primarily caused by vapour migration, whereas that in the unfrozen zone is primarily caused by liquid water migration. The final migration height of liquid water and the amount of vapour migration are positively correlated with the amplitude and frequency of dynamic loading. Continuous pore-structure changes and soil-particle movement provide favourable conditions for vapour migration, which are amplified by increasing the dynamic loading amplitude or frequency. A pumping action produced by dynamic loading exists inside CGS. In the design and maintenance of HSR subgrades in cold regions, vapour migration merits careful consideration because it induces more than 50% of the frost-heaving displacement.
•The vapour migration is dominant in CGS under HSR train loading.•The migration height of liquid water increases in loading amplitude or frequency.•Liquid water and vapour have different contribution on water redistribution of CGS.
A novel niobium oxyiodate sulfate, Nb2O3(IO3)2 (SO4), was fabricated by a rational multi‐component design under moderate hydrothermal conditions. This multi‐component design is inspired by an ...interesting niobium oxysulfate reaction, which opens a new door for synthetic method to effectively introduce refractory metals such as Nb into crystal structures by hydrothermal synthesis. Nb2O3(IO3)2(SO4) features a cube‐like topological structure with a large phase‐matching second harmonic generation (SHG) response (6×KDP), a wide transparency window (0.38–8 μm), and a high laser damage threshold (LDT) (20×AgGaS2). It has the highest thermostability (stable up to 580 °C under air) among reported non‐centrosymmetric (NCS) iodates and sulfates and is stable in water and even concentrated H2SO4. Furthermore, Nb2O3(IO3)2(SO4) is a unique nonlinear optical (NLO) material among iodates and sulfates, because its SHG effect is mainly caused by the MO6 units rather than the IO3 or SO4 units, which is demonstrated by density functional theory (DFT) calculations.
Oh my‐obium! The synthesis of crystalline Nb2O3(IO3)2(SO4) under moderate hydrothermal conditions is reported. The highly thermostable crystal features a strong second‐harmonic‐generation response, a wide transparency window, and a high laser damage threshold.
Variations in the N2-fixing activity of azolla by species and weather, and the effect of light intensity and temperature on azolla N2-fixing activity were studied. A direct method for measuring ...N2-fixing activity without changing the ecological conditions or growth of azolla is described. An experimental formula for calculating the daily amount of N2 fixed by azolla (g/g dry wt) is given. Azolla successively determined at 0600, 1000, 1400, and 1800 h, respectively. The formula was derived from the successive determination of N2-fixing activity in the natural environment. Optimum light intensity and growth temperature for N2-fixing varies by azolla sp. and season. That is why the amount of N2 fixed by azolla should be calculated on the basis of successive determinations. The reaction time for the determinations was found to be 10 min and a factor to convert the amount of fixed N2 from that of reduced C2H2 was found to be 3. For gas chromatographic analysis, the ratio of NC2H4/Nc2H2 (content ratio) was not proportional to HC2H4/HC2H2 (peak height ratio). This ratio should be determined experimentally.
Two new isostructural non-centrosymmetric cerium iodates KxCe9(IO3)36 (x ≈ 3) and LaxCe9(IO3)36 (x ≈ 0.3) were synthesized via a hydrothermal method and systematically characterized. They are ...intermediate valence compounds with the same band gap, showing similar microscopic net dipole moments per unit volume, but different macroscopic second-harmonic generation (SHG) responses under 1064 nm laser irradiation. This research gives a new view for understanding the effects of electronic structure on the SHG response.
Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by elevated serum anti-mitochondrial Ab and lymphocyte-mediated bile duct damage. This study was designed to reveal the ...clonal characteristics of B lymphocyte repertoire in patients with PBC to facilitate better understanding of its pathogenesis and better management of these patients. Using high-throughput sequencing of Ig genes, we analyzed the repertoire of circulating B lymphocytes in 43 patients with PBC, and 34 age- and gender-matched healthy controls. Compared with healthy controls, PBC patients showed 1) a gain of 14 new clones and a loss of 8 clones; 2) a significant clonal expansion and increased relative IgM abundance, which corresponded with the elevated serum IgM level; 3) a significant reduction of clonal diversity and somatic hypermutations in class-switched sequences, which suggested a general immunocompromised status; 4) the reduction of clonal diversity and enhancement of clonal expansion were more obvious at the cirrhotic stage; and 5) treatment with ursodeoxycholic acid could increase the clonal diversity and reduce clonal expansion of the IgM repertoire, with no obvious effect on the somatic hypermutation level. Our data suggest that PBC is a complex autoimmune disease process with evidence of B lymphocyte clonal gains and losses, Ag-dependent ogligoclonal expansion, and a generally compromised immune reserve. This new insight into the pathogenesis of PBC opens up the prospect of studying disease-relevant B cells to better diagnose and treat this devastating disease.
Channel avulsion is a natural phenomenon that occurs abruptly on alluvial river deltas, which can affect the channel stability. The causes for avulsion could be generally categorized as topography- ...and flood-driven factors. However, previous studies on avulsion thresholds usually focused on topography-driven factors due to the centurial or millennial avulsion timescales of the world’s most deltas, but neglected the impacts of flood-driven factors. In the current study, a novel demarcation equation including the two driven factors was proposed, with the decadal timescale of avulsion being considered in the Yellow River Estuary (YRE). In order to quantify the contributions of different factors in each category, an entropy-based methodology was used to calculate the contributing weights of these factors. The factor with the highest weight in each category was then used to construct the demarcation equation, based on avulsion datasets associated with the YRE. An avulsion threshold was deduced according to the demarcation equation. This avulsion threshold was then applied to conduct the risk assessment of avulsion in the YRE. The results show that: two dominant factors cover respectively geomorphic coefficient representing the topography-driven factor and fluvial erosion intensity representing the flood-driven factor, which were thus employed to define a two dimensional mathematical space in which the demarcation equation can be obtained; the avulsion threshold derived from the equation was also applied in the risk assessment of avulsion; and the avulsion threshold proposed in this study is more accurate, as compared with the existing thresholds.
Two new isostructural non-centrosymmetric cerium iodates K
Ce
(IO
)
(x≈ 3) and La
Ce
(IO
)
(x≈ 0.3) were synthesized via a hydrothermal method and systematically characterized. They are intermediate ...valence compounds with the same band gap, showing similar microscopic net dipole moments per unit volume, but different macroscopic second-harmonic generation (SHG) responses under 1064 nm laser irradiation. This research gives a new view for understanding the effects of electronic structure on the SHG response.
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