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Soil salinization is a critical environmental issue restricting agricultural production. Straw deep returning as interlayer (40 cm) has been a popularized practice to alleviate salt stress. However, the legacy effects of straw interlayer associated with the straw input amount on soil organic carbon (SOC) and total nitrogen (TN) in saline soil remain unclear. Therefore, a four-year (2015-2018) field experiment was conducted with four levels (i.e., 0, 6, 12 and 18 Mg ha ) of straw returning as interlayer. Compared with no straw interlayer (CK), straw interlayers increased SOC content by 14-32% and 11-57% in 20-40 cm and 40-60 cm, respectively. Lower increases were for soil TN content (8-22% in 20-40 cm and 6-34% in 40-60 cm) than SOC content, which led to increase soil C:N ratio in the 20-60 cm soil depth. Compared with CK, remarkable increases of SOC and soil TN contents in 20-60 cm led to the decrease of stratification ratios (0-20: 20-60 cm), which promoted uniform distributions of SOC and TN in soil profiles. Even though soil parameters ranged widely according to the straw input, straw interlayer with 12 Mg ha had higher SOC, TN, C:N ratio, and lower soil stratification ratio in 2015-2017, which contributed to salt leaching, water retention, and yield increment. These results highlighted the legacy effects of straw interlayers maintained more than four years, which led to an underestimation for previous short-term experiments, and demonstrated a great potential for subsoil fertility and salt-affected soil amelioration.

A photo zipper locked DNA nanomachine with an internal standard is presented, preventing nonspecific activation and providing efficient intracellular miRNA imaging., DNA nanomachines are capable of converting tiny triggers into autonomous accelerated cascade hybridization reactions and they have been used as a signal amplification strategy for intracellular imaging. However, the “always active” property of most DNA nanomachines with an “absolute intensity-dependent” signal acquisition mode results in “false positive signal amplification” by extracellular analytes and impairs detection accuracy. Here we design a photo zipper locked miRNA responsive DNA nanomachine (PZ-DNA nanomachine) based on upconversion nanoparticles (UCNPs) with a photo-cleavable DNA strand to block the miRNA recognition region, which provided sufficient protection to the DNA nanomachine against nonspecific extracellular activation and allowed satisfactory signal amplification for sensitive miRNA imaging after intracellular photoactivation. Multiple emissions from the UCNPs were also utilized as an internal standard to self-calibrate the intracellular miRNA responsive fluorescence signal. The presented PZ-DNA nanomachine demonstrated the sensitive imaging of intracellular miRNA from different cell lines, which resulted in good accordance with qRT-PCR measurements, providing a universal platform for precise imaging in living cells with high spatial–temporal specificity.

The combination of plastic film mulching and subsurface organic amendment is a novel strategy for saline soil amelioration and utilization in China. However, how the strategy affect soil organic carbon (SOC) contents directly and indirectly (physical protection and microbiological regulation) were still not-documented. Therefore, four treatments, i.e., no amendment with and without plastic film mulching, subsurface (10-30 cm soil depth) organic amendment with and without plastic film mulching, were arranged and sampled after three-year filed experiment. Compared with no amendment with and without plastic film mulching, subsurface organic amendment increased the SOC content in the 0-40 cm soil depth by 70% and 90%, respectively. Plastic film mulching decreased SOC by 16% without organic amendment. Subsurface organic amendment transformed the dominant aggregation particles from

Clarifying the relationship between salt-affected soils and their adjacent river systems is critical to address the challenges posed by soil salinization on agricultural production. Among the various biophysical and land management factors linked to soil salinization, few studies have investigated the importance of the distance along the river. Based on the Hetao Irrigation District of the Yellow River Basin, we collected 5314 soil samples and analyzed 17 soil parameters to explore the relationship between salt-affected soils and their distance along the river. Soil salinization was reinforced by the distance along the river, as a trade-off between soil ion accumulation and nutrient regulation. Soil total water-soluble salt content increased by 16.4 mg kg−1 every kilometer, likely due to ions leaching from the soils upstream and partially accumulating in the soils downstream, especially for Cl-, SO42-, and Na+. Greater input and less solubility of Ca2+ based soil amendments, phosphorus fertilizers, and organic materials on the less salt-affected soils upstream may explain the declines in soil Ca2+, available phosphorus, and soil organic matter with distance along the river. With every kilometer along the river, soil exchangeable sodium and cation exchange capacity increased by 8.89 × 10−4 and 1.26 × 10−2 cmol kg−1, respectively, which led to an increase in soil exchangeable sodium percentage by 9.59 × 10−5. The increase in soil exchangeable sodium along the river was mainly due to Na+ accumulation, while soil cation exchange capacity was regulated by soil organic matter and total nitrogen. Soil pH increased by 1.21 × 10−3 per kilometer along the river, associated with the decrease of soil organic matter. Future saline soil amelioration and reutilization initiatives at regional scales may be improved by accounting for the changes in soil physicochemical properties resulting from the distance along the river.

Two series of D-π-A 4H-pyran derivatives using 1H-indene-1,3(2H)-dione as an electron-withdrawing, namely asymmetric AP-1-AP-3 and symmetric SP-1-SP-3, were synthesized to investigate the effect of the molecular symmetry on their mechanofluorochromic (MFC) activities. All these compounds with twisted molecular conformations exhibit obvious aggregation-induced emission properties caused by the restriction of intramolecular rotation in the aggregated sate. Although AP-1 and SP-1 are MFC-inactive, methyl-substituted AP-2 and trifluoromethyl-substituted AP-3 with low symmetry display reversible MFC activities, whereas the corresponding compounds SP-2 and SP-3 with high symmetry have no obvious solid-state emission color changes upon grinding. The results indicate the effect of the introduction of methyl and trifluoromethyl groups on the MFC properties of these compounds is controlled by the molecular symmetry. The MFC properties of AP-2 and AP-3 are ascribed to the phase transition from a crystalline state to another and an amorphous state, respectively, as revealed by X-ray diffraction and differential scanning calorimetry experiments. Our results indicate that the adjustment of the molecular symmetry can be regarded as a way of constructing a new and/or high-contrast MFC-active material from a particular MFC-inactive molecule.

Transformed diffusions (TDs) have become increasingly popular in financial modeling for their model flexibility and tractability. While existing TD models are predominately one-factor models, empirical evidence often prefers models with multiple factors. We propose a novel distribution-driven nonlinear multifactor TD model with latent components. Our model is a transformation of a underlying multivariate Ornstein–Uhlenbeck (MVOU) process, where the transformation function is endogenously specified by a flexible parametric stationary distribution of the observed variable. Computationally efficient exact likelihood inference can be implemented for our model using a modified Kalman filter algorithm and the transformed affine structure also allows us to price derivatives in semi-closed form. We compare the proposed multifactor model with existing TD models for modeling VIX and pricing VIX futures. Our results show that the proposed model outperforms all existing TD models both in the sample and out of the sample consistently across all categories and scenarios of our comparison.