An ‘anomalous' negative flux, in which carbon dioxide (CO2) enters rather than is released from the ground, was studied in a saline/alkaline soil. Soil sterilization disclosed an inorganic process of CO2 dissolution into (during the night) and out of (during the day) the soil solution, driven by variation in soil temperature. Experimental and modeling analysis revealed that pH and soil moisture were the most important determinants of the magnitude of this inorganic CO2 flux. In the extreme cases of air-dried saline/alkaline soils, this inorganic process was predominant. While the diurnal flux measured was zero sum, leaching of the dissolved inorganic carbon in the soil solution could potentially effect net carbon ecosystem exchange. This finding implies that an inorganic module should be incorporated when dealing with the CO2 flux of saline/alkaline land. Neglecting this inorganic flux may induce erroneous or misleading conclusions in interpreting CO2 fluxes of these ecosystems.
In resource-poor environments, adjustment in plant biomass allocation implies a complex interplay between environmental signals and plant development rather than a delay in plant development alone. To understand how environmental factors influence biomass allocation or the developing phenotype, it is necessary to distinguish the biomass allocations resulting from environmental gradients or ontogenetic drift. Here, we compared the development trajectories of cotton plants (Gossypium herbaceum L.), which were grown in two contrasting soil textures during a 60-d period. Those results distinguished the biomass allocation pattern resulting from ontogenetic drift and the response to soil texture. The soil texture significantly changed the biomass allocation to leaves and roots, but not to stems. Soil texture also significantly changed the development trajectories of leaf and root traits, but did not change the scaling relationship between basal stem diameter and plant height. Results of nested ANOVAs of consecutive plant-size categories in both soil textures showed that soil gradients explained an average of 63.64–70.49% of the variation of biomass allocation to leaves and roots. Ontogenetic drift explained 77.47% of the variation in biomass allocation to stems. The results suggested that the environmental factors governed the biomass allocation to roots and leaves, and ontogenetic drift governed the biomass allocation to stems. The results demonstrated that biomass allocation to metabolically active organs (e.g., roots and leaves) was mainly governed by environmental factors, and that biomass allocation to metabolically non-active organs (e.g., stems) was mainly governed by ontogenetic drift. We concluded that differentiating the causes of development trajectories of plant traits was important to the understanding of plant response to environmental gradients.
Species competitive abilities and their distributions are closely related to functional traits such as biomass allocation patterns. When we consider how nutrient supply affects competitive abilities, quantifying the apparent and true plasticity in functional traits is important because the allometric relationships among traits are universal in plants. We propose to integrate the notion of allometry and the classical reaction norm into a composite theoretical framework that quantifies the apparent and true plasticity. Combining the framework with a meta-analysis, a series of field surveys and a competition experiment, we aimed to determine the causes of the dune/interdune distribution patterns of two Haloxylon species in the Gurbantonggut Desert. We found that (1) the biomass allocation patterns of both Haloxylon species in responses to environmental conditions were apparent rather than true plasticity and (2) the allometric allocation patterns affected the plants’ competition for soil nutrient supply. A key implication of our results is that the apparent plasticity in functional traits of plants determines their response to environmental change. Without identifying the apparent and true plasticity, we would substantially overestimate the magnitude, duration and even the direction of plant responses in functional traits to climate change.
Frizzled (FZD) proteins are receptors for secreted WNT proteins and play a critical role in the malignant progression of various cancers. However, the role of human FZD family members in esophageal squamous cell carcinoma (ESCC) was rarely investigated. In this study, we found that the FZD7 gene was the most commonly up-regulated FZD member in ESCC cell lines compared with other FZDs. TMA studies further validated that FZD7 protein was up-regulated in 165 of 252 (65.5%) informative ESCC patients and significantly correlated with poor overall survival (P=0.001). Additionally, multivariate Cox regression analysis showed that FZD7 overexpression was an independent prognostic factor for ESCC patients. Ectopic expression of FZD7 could promote ESCC cell metastasis both in vitro and in vivo. Under WNT3A stimulation, FZD7 was able to induce the nuclear translocation of β-catenin and activate the downstream targets of WNT/β-catenin signaling, as well as promote epithelial-mesenchymal transition (EMT) potential in ESCC cells. Our study demonstrated for the first time that FZD7 contributes to the malignant progression of ESCC and represents a novel prognostic marker and a potential therapeutic target for ESCC patients.
Development of liquid-phase separated bulk metallic glasses is retarded due to difficulties in finding of immiscible systems with high glass-forming ability (GFA) of coexistent liquids. Zr-Ce alloy is a typical liquid immiscible system characterized by a liquid miscibility gap. We added Co and Cu into the Zr-Ce immiscible system and optimized the composition of the designed Zr-Ce-Co-Cu immiscible alloys. The solidification experiments were carried out for the quaternary alloys. The result indicates that the melt separated into ZrCo-rich and CeCu-rich liquids upon cooling through the miscibility gap. By optimizing the relative atomic ratio of Co:Cu, the coexistent ZrCo-rich and CeCu-rich liquids automatically assembled eutectic compositions during the liquid-liquid phase separation (LLPS). Under the condition of fast quenching, the two liquids subsequently undergo liquid-to-glass transition, resulting in the formation of composite structure with two glasses in the samples. We successfully developed phased-separated metallic glasses based on the Zr-Ce-Co-Cu immiscible alloys. This work not only strengthens the understanding in the LLPS but also provides a new strategy on the design of the dual glassy composites.
This is an open access article under the terms of the Creat ive Commo ns Attri bution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
[1] Viaducts over roads are common in many cities. In this paper, a three-dimensional multiray tracing model for in-vehicle mobile digital TV was used to explore the propagation properties of ultrahigh frequency waves under viaducts, subject to the transmitting antenna being higher than viaduct deck. The model is based on geometrical optics, physical optics, geometrical theories of diffraction, and especially the uniform theory of diffraction. The model takes into account direct propagation, ground reflection, transmission, as well as wedge diffraction to reveal the law of signal path gain under viaducts. Validation results show good agreement between calculated and measured data. The prediction for linearly, especially vertically polarized wave propagation provided by a six-ray model may be more helpful than that provided by a four-ray model.
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