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The precipitation mechanism of the Q phase in Al–Mg–Si–Cu alloys has long been the subject of ambiguity and debate since its metastable phase (Q′) has the same crystal structure and similar lattice parameters as its equilibrium counterparts. In the present work, the evolution of the Q′ (Q) phase during aging is studied by combination of quantitative atomic-resolution scanning transmission electron microscopy and atom probe tomography. It was found that the transformation from the Q′ to the Q phase involves changes of the occupancy of Al atoms in atomic columns of the Q′ (Q) phase. The Al atoms incorporated in the Cu, Si and Mg columns are gradually released into the Al matrix, while mixing between Cu and Si atoms occurs in the Si columns. This transformation process is mainly attributed to the low lattice misfit of the equilibrium Q phase. Besides, the formation of various compositions of the Q phase is due to the different occupancy in the atomic columns of the Q phase. The occupancy changes in the columns of the Q phase are kinetically controlled and are strongly influenced by the alloy composition and aging temperature.

Harvesting energy through water motion on solid surface is significantly important due to the energy generation intermittency of the usually used energy transducers. In this paper, n-type silicon thin film is fabricated through magnetron sputtering followed by rapid thermal processing under different temperatures. The influence of the annealing temperatures on film crystallinity, phase, conductivity and conductivity activation energy is systematically investigated. Moreover, the voltage outputs on different silicon films through the sliding of NaCl solution droplet are systematically discussed. With increasing the annealing temperature from 300 to 900 °C, the voltage value increases firstly and then decreases, achieving a highest value of 1060 mV on the sample annealed at 600 °C, which is much higher than that of the mostly reported carbon materials. Finally, a schematic model, which is based on the combined effect of contact potential change between NaCl solution droplet and silicon film accompanied with the variation of the film conductivity, is proposed to unveil the underlying mechanism behind voltage output on various silicon films. All the findings provide not only a platform for achieving a higher output voltage but also a mechanism for a better understanding of the water motion induced energy harvesting.

The understanding of metastable hardening precipitate evolution in Al-Mg-Si(-Cu) is still quite confused and elusive due to the disordered nature of several precipitates and the complex processes involved. Atomic-resolution scanning transmission electron microscopy is used here to study the nucleation and transformation mechanisms of the B′/Q′ precipitates in the Al-Mg-Si(-Cu) alloys. It is emphasized that understanding the formation and evolution of short-range order (SRO) in the precipitates is a core to revealing their transformation mechanisms. Although the B′ and Q′ phases have the same crystal structure, and both originate from the β″ precipitate, the formation mechanisms of these two precipitates are different. For B′, formed in the Al-Mg-Si alloy, the β″ phase initially transforms to the U2 phase by the transition of the “low density cylinder” (LDC) to Mg hexagons. Subsequently, the U2 phase transforms to the B′ phase by the rotation of Al-Si columns, and the formation and ordering of triangle B′ sub-units. For Q′, formed in the Al-Mg-Si-Cu alloy, the Cu atoms incorporate initially the interior of the β″ phase and form the substructure of Cu sub-unit clusters. In most cases, these Cu sub-unit clusters are randomly distributed, and the QM and QP lattices are formed throughout the precipitates. In some precipitates, the arrangement of Cu sub-unit clusters however constitutes a hexagonal lattice and leads to the formation of the QC phase. During subsequent aging, the formation and ordering of the triangle Q′ sub-units can lead to the formation of the Q′ phase. Clarifying the role of the SRO in these processes provides a new insight in the understanding of transformation mechanisms of precipitates in Al-Mg-Si(-Cu) alloys.

The effects of double-step homogenization processes on the precipitation of Al3Zr dispersoids and the dissolution of the primary phases of 2196 aluminum alloy were studied by optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was revealed that first-step homogenization facilitates the nucleation of Al3Zr, while second-step homogenization results in the dissolution of the primary phases and the growth of Al3Zr dispersoids. The nanosized θ’ precipitates formed in the first-step homogenization are dissolved after the second-step homogenization. The optimum homogenization process was selected as 400 °C/10 h + 520 °C/24 h, which effectively dissolves the primary phases and promotes the formation of refined distribution of Al3Zr dispersoids. This phenomenon is mainly caused by the highest nucleation rate of the Al3Zr phase at 400 °C. While reducing the heating rate of the homogenization process can increase the number density of the Al3Zr dispersoids and reduce the precipitate free zone (PFZ), it does not alleviate the inhomogeneity of the Al3Zr precipitation. These results are expected to be meaningful for tailoring the industrial homogenization processing of as-cast Al-Cu-Li alloy.

Controlling the formation of the β′ (Al3Zr) phase is pivotal for regulating the recrystallization and thus the mechanical properties of the spray formed 2195 (Al-Cu-Li) alloy. In a conventional “homogenization-extrusion” process, the precipitation of β′ is severely affected by the presence of the T1(Al2CuLi) phase in the as-deposited alloy, leading to an inhomogeneous distribution of the β′ phase. In the present work, we propose a new thermomechanical processing (TMP)—swapping the order of the homogenization and extrusion processes. The microstructures and properties of the new proposed TMP were systematically studied at various stages of the alloy treatment and compared with the out of the conventional TMP. It was revealed that the introduction of the extrusion process on the as-deposited alloy can break the continuous network of primary phases and dissolve the T1 phase, promoting a uniform distribution of the β′ phase during subsequent two-step homogenization. During solution treatment, the new TMP is more effectively in suppressing the formation of a coarse grain layer at sheet surface, while after final peak aging, the new TMP produces a lower alloy strength but a higher elongation, due mainly to the smaller thickness reduction during deformation. The new proposed TMP technique provides a new insight into regulating the mechanical properties of Al-Cu-Li alloys.

The effects of double-step homogenization processes on the precipitation of Al[sub.3]Zr dispersoids and the dissolution of the primary phases of 2196 aluminum alloy were studied by optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was revealed that first-step homogenization facilitates the nucleation of Al[sub.3]Zr, while second-step homogenization results in the dissolution of the primary phases and the growth of Al[sub.3]Zr dispersoids. The nanosized θ’ precipitates formed in the first-step homogenization are dissolved after the second-step homogenization. The optimum homogenization process was selected as 400 °C/10 h + 520 °C/24 h, which effectively dissolves the primary phases and promotes the formation of refined distribution of Al3Zr dispersoids. This phenomenon is mainly caused by the highest nucleation rate of the Al[sub.3]Zr phase at 400 °C. While reducing the heating rate of the homogenization process can increase the number density of the Al[sub.3]Zr dispersoids and reduce the precipitate free zone (PFZ), it does not alleviate the inhomogeneity of the Al[sub.3]Zr precipitation. These results are expected to be meaningful for tailoring the industrial homogenization processing of as-cast Al-Cu-Li alloy.

Traditionally, transfer RNAs (tRNAs) specifically decoded messenger RNA (mRNA) and participated in protein translation. tRNA-derived fragments (tRFs), also known as tRNA-derived small RNAs (tsRNAs), are generated by the specific cleavage of pre- and mature tRNAs and are a class of newly defined functional small non-coding RNAs (sncRNAs). Following the different cleavage positions of precursor or mature tRNA, tRFs are classified into seven types, 5′-tRNA half, 3′-tRNA half, tRF-1, 5′U-tRF, 3′-tRF, 5′-tRF, and i-tRF. It has been demonstrated that tRFs have a diverse range of biological functions in cellular processes, which include inhibiting protein translation, modulating stress response, regulating gene expression, and involvement in cell cycles and epigenetic inheritance. Emerging evidences have indicated that tRFs in extracellular vesicles (EVs) seem to act as regulatory molecules in various cellular processes and play essential roles in cell-to-cell communication. Furthermore, the dysregulation of EV-associated tRFs has been associated with the occurrence and progression of a variety of cancers and they can serve as novel potential biomarkers for cancer diagnosis. In this review, the biogenesis and classification of tRFs are summarized, and the biological functions of EV-associated tRFs and their roles as potential biomarkers in human diseases are discussed.

Broadband spectral photoresponse has shown bright prospects for various optoelectronic devices, while fulfilling high photoactivity beyond the material bandgap is a great challenge. Here, we present a molecular pyroelectric, N -isopropylbenzylaminium trifluoroacetate ( N -IBATFA), of which the broadband photo-pyroelectric effects allow for self-driven wide spectral photodetection. As a simple organic binary salt, N -IBATFA possesses a large polarization (~9.5 μC cm −2 ), high pyroelectric coefficient (~6.9 μC cm −2 K −1 ) and figures-of-merits ( F V  = 187.9 × 10 −2 cm 2 μC −1 ; F D  = 881.5 × 10 −5  Pa −0.5 ) comparable to the state-of-art pyroelectric materials. Particularly, such intriguing attributes endow broadband photo-pyroelectric effect, namely, transient currents covering ultraviolet (UV, 266 nm) to near-infrared (NIR, 1950 nm) spectral regime, which breaks the restriction of its optical absorption and thus allows wide UV-NIR spectral photodetection. Our finding highlights the potential of molecular system as high-performance candidates toward self-powered wide spectral photodetection. Broadband spectral photoresponse has potential for optoelectronic devices, but obtaining high photoactivity beyond the material bandgap is challenging. Here, the authors report the development of a molecular pyroelectric material with broadband photopyroelectric effects.

as a crucial afforestation species in semi-arid regions, faces issues such as the reduction of plantations. Calcium plays a significant role in alleviating drought stress and promoting nutrient uptake in plants. Utilizing a pot experiment approach, seedlings were treated with exogenous calcium at five concentrations (0, 50, 100, 200, and 400 mg•kg-1). The nutrient content of the plants and soil was measured, and their ecological stoichiometric characteristics and internal stability were analyzed. This was followed by a series of related studies. As the concentration of calcium increases, the contents of carbon, nitrogen, phosphorus, and potassium in various organs and the whole plant exhibit a trend of first increasing and then decreasing, peaking at calcium treatment of 50-100 mg•kg-1. Concurrently, the calcium concentration in plant organs and the entire plant gradually increases with the availability of calcium in the soil. The addition of exogenous calcium has a certain impact on the ecological stoichiometric ratios (C:N, C:P, N:P) of seedlings' leaves, stems, roots, and the whole plant, exhibiting distinct variation characteristics. At calcium concentrations of 50-100 mg•kg-1, the ratios of C:N and C:P are relatively lower. Under calcium concentrations of 0, 50, and 100 mg•kg-1, soil calcium shows a positive correlation with the total carbon (TC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), and calcium contents in leaves, stems, roots, and the entire plant. However, at calcium concentrations of 200 and 400 mg•kg-1, soil calcium exhibits a significant positive correlation with the calcium content in leaves, stems, roots, and the entire plant, and a significant negative correlation with the total phosphorus, total nitrogen, total phosphorus, and total potassium contents. After the addition of exogenous calcium at different concentrations, most stoichiometric indices of various organs of seedlings demonstrate strong balance. Calcium, as an essential structural component and second messenger, regulates the nutrient uptake and utilization in plants, influencing the stoichiometry. However, both low and high concentrations of calcium can be detrimental to plant growth by disrupting nutrient metabolism and internal structures. Consequently, there exists an optimal calcium concentration for nutrient absorption.

Background After millions of years of coevolution, symbiotic microbiota has become an integral part of the host and plays an important role in host immunity, metabolism, and health. Vaccination, as an effective means of preventing infectious diseases, has been playing a vital role in the prevention and control of human and animal diseases for decades. However, so far, minimal is known about the effect of vaccination on fish symbiotic microbiota, especially mucosal microbiota, and its correlation with intestinal metabolism remains unclear. Methods Here we reported the effect of an inactivated bivalent Aeromonas hydrophila / Aeromonas veronii vaccine on the symbiotic microbiota and its correlation with the intestinal metabolism of farmed adult Nile tilapia ( Oreochromis niloticus ) by 16S rRNA gene high-throughput sequencing and gas chromatography-mass spectrometry metabolomics. Results Results showed that vaccination significantly changed the structure, composition, and predictive function of intestinal mucosal microbiota but did not significantly affect the symbiotic microbiota of other sites including gill mucosae, stomach contents, and stomach mucosae. Moreover, vaccination significantly reduced the relative abundance values of potential opportunistic pathogens such as Aeromonas , Escherichia – Shigella , and Acinetobacter in intestinal mucosae. Combined with the enhancement of immune function after vaccination, inactivated bivalent Aeromonas vaccination had a protective effect against the intestinal pathogen infection of tilapia. In addition, the metabolite differential analysis showed that vaccination significantly increased the concentrations of carbohydrate-related metabolites such as lactic acid, succinic acid, and gluconic acid but significantly decreased the concentrations of multiple lipid-related metabolites in tilapia intestines. Vaccination affected the intestinal metabolism of tilapia, which was further verified by the predictive function of intestinal microbiota. Furthermore, the correlation analyses showed that most of the intestinal differential microorganisms were significantly correlated with intestinal differential metabolites after vaccination, confirming that the effect of vaccination on intestinal metabolism was closely related to the intestinal microbiota. Conclusions In conclusion, this paper revealed the microbial and metabolic responses induced by inactivated vaccination, suggesting that intestinal microbiota might mediate the effect of vaccination on the intestinal metabolism of tilapia. It expanded the novel understanding of vaccine protective mechanisms from microbial and metabolic perspectives, providing important implications for the potential influence of vaccination on human intestinal microbiota and metabolism. -tufGxbkxhm-UiFTxxYHNi Video Abstract