Search

Toughening polymers has attracted significant interest. Traditionally, polymer toughness is enhanced by constructing polymer networks or introducing sacrificial bonds into the chains between crosslink points. These strategies, though, introduce pronounced energy dissipation and associated heat, both of which are undesirable under long-term cyclic loading, for example at the interface of implants in the human body. By incorporating single-chain nanoparticles (SCNPs) into linear polymer chains to generate all-polymer nanocomposites (APNCs), we have been able to achieve high strength, high toughness with low energy dissipation. Using a combination of simulation and experimental results, we are advancing a “SCNPs effect” where tightly cross-linked SCNPs produce a modulus contrast to achieve strengthening and toughening. Benefitting from the soft interface, the penetrable and deformable SCNPs cause the surrounding polymer chains to move in concert, significantly reducing the interfacial friction to achieve low energy dissipation. The intramolecular cross-linking of the SCNPs and adhesion between the SCNPs and polymer matrix are critical for realizing such high-performance systems. Based on a Gaussian regression model and back propagation (BP) neural network, the mechanical strength can be predicted and is supported by simulations. The APNC concept described can be applied to elastomers and gels, broadening its utilization in high-cycle and low-dissipation applications, like soft robots, flexible sensors and cartilage replacements, and artificial heart valves.

As a critical component of substations, the substation frames are characterized by significant height and span, which presents substantial challenges and risks in conducting dynamic response tests using traditional sensors. To simplify these difficulties, this paper introduces an experimental method utilizing MEMS sensor-based vibration acquisition. In this approach, smartphones equipped with MEMS sensors are deployed on the target structure to collect vibration data under environmental excitation. This method was applied in a dynamic field test of a novel composite substation frame. During the test, the proposed MEMS-based vibration acquisition method was conducted in parallel with traditional ultra-low-frequency vibration acquisition methods to validate the accuracy of the MEMS data. The results demonstrated that the MEMS sensors not only simplified the testing process but also provided reliable data, offering greater advantages in testing convenience compared with traditional contact methods. The modal parameters of the substation frame, including modal frequencies, damping ratios, and mode shapes, were subsequently identified using the covariance-driven stochastic subspace identification method. The experimental methodology and findings presented in this paper offer valuable insights for structural dynamic response testing and the wind-resistant design of substation frames. [ABSTRACT FROM AUTHOR]

Norisoprenoids are important chemical compounds to grape and wine aroma, and their content in the grape berries can be greatly affected by varietal, terroir, and environmental factors. In this study, we investigate how major factors, such as genotype and climate conditions, influence the physicochemical properties of grape juice, volatile C13-norisoprenoid compounds, and gene expression profiles of three Vitis vinifera grape varieties: Muscat blanc à Petit grain, Muscat à petits grains rouges, and Gewürztraminer during the production period in 2010 and 2011. The total soluble solids (TSS) of both Muscat varieties were significantly higher in 2011 compared to 2010, reflecting interannual climatic variations, while Gewürztraminer showed no significant differences. At full maturity, total acid of all three cultivars was consistent between the years, indicating genetic determination. Thirteen norisoprenoids were identified, with Muscat varieties showing consistently higher levels than Gewürztraminer, irrespective of the production year. Varietal differences were significant for 13 out of 14 volatile compounds, and vintage effects were notable for 11 compounds, including key aroma contributors β-damascenone and β-ionone. OPLS-DA analysis highlighted distinct volatile profiles for each variety and vintage, influenced by climatic factors such as precipitation and sunlight hours. Gene expression analysis revealed strong correlations between VvCCD1, VvCCD4a, and VvCCD4b genes and C13-norisoprenoid accumulation, with these genes also implicated in the ABA biosynthesis pathway. Single nucleotide polymorphisms (SNPs) in VvCCD1, VvCCD4a, and VvCCD4b were linked to variations in norisoprenoid content among the cultivars. Altogether, these findings revealed the interaction of genetic and environmental factors in shaping the physicochemical properties for the grape, volatile profiles, and gene expression patterns of grape berries, with significant implications for viticulture and the winemaking process. [ABSTRACT FROM AUTHOR]

Agricultural crops are targeted by various pathogens (fungi, bacteria, and viruses) and pests (herbivorous arthropods). Antimicrobial and insecticidal peptides are increasingly recognized as eco‐friendly tools for crop protection due to their low propensity for resistance development and the fact that they are fully biodegradable. However, historical challenges have hindered their development, including poor stability, limited availability, reproducibility issues, high production costs, and unwanted toxicity. Toxicity is a primary concern because crop‐protective peptides interact with various organisms of environmental and economic significance. This review focuses on the potential of genetically encoded peptide libraries like the use of two‐hybrid‐based methods for antimicrobial peptides identification and insecticidal spider venom peptides as two main approaches for targeting plant pathogens and pests. We discuss some key findings and challenges regarding the practical application of each strategy. We conclude that genetically encoded peptide library‐ and spider venom‐derived crop protective peptides offer a sustainable and environmentally responsible approach for addressing modern crop protection needs in the agricultural sector. [ABSTRACT FROM AUTHOR]

Lilium is one of the most widely cultivated ornamental bulbous plants in the world. Although research has shown that variable temperature treatments can accelerate the development process from vegetative to reproductive growth in Lilium, the molecular regulation mechanisms of this development are not clear. In this study, Lbr-miR171b and its target gene, LbrSCL6, were selected and validated using transgenic functional verification, subcellular localization, and transcriptional activation. This study also investigated the differential expression of Lbr-miR171b and LbrSCL6 in two temperature treatment groups (25 °C and 15 °C). Lbr-miR171b expression significantly increased after the temperature change, whereas that of LbrSCL6 exhibited the opposite trend. Through in situ hybridization experiments facilitated by the design of hybridization probes targeting LbrSCL6, a reduction in LbrSCL6 expression was detected following variable temperature treatment at 15 °C. The transgenic overexpression of Lbr-miR171b in plants promoted the phase transition, while LbrSCL6 overexpression induced a delay in the phase transition. In addition, LbrWOX4 interacted with LbrSCL6 in yeast two-hybrid and bimolecular fluorescence complementation assays. In conclusion, these results explain the molecular regulatory mechanisms governing the phase transition in Lilium. [ABSTRACT FROM AUTHOR]

Myocardial ischemia–reperfusion injury (MIRI) is a common clinic scenario that occurs in the context of reperfusion therapy for acute myocardial infarction. It has been shown that cocaine and amphetamine‐regulated transcript (CART) can ameliorate cerebral ischemia–reperfusion (I/R) injury, but the effect of CART on MIRI has not been studied yet. Here, we revealed that CART protected the heart during I/R process by inhibiting apoptosis and excessive autophagy, indicating that CART would be a potential drug candidate for the treatment of MIRI. Further analysis showed that CART upregulated the activation of phospho‐AKT, leading to downregulation of lactate dehydrogenase (LDH) release, apoptosis, oxidative stress and excessive autophagy after I/R, which was inhibited by PI3K inhibitor, LY294002. Collectively, CART attenuated MIRI through inhibition of cardiomyocytes apoptosis and excessive autophagy, and the protective effect was dependent on PI3K/AKT signalling pathway. [ABSTRACT FROM AUTHOR]

Q-switched fiber lasers have become reliable light sources for generating high-energy pulses, which can be passively modulated by saturable absorbers with excellent nonlinear optical properties. The composite combining Ag and MXene exhibits a broadband nonlinear response and high modulation depth, making it a promising candidate for saturable absorbers in pulsed lasers. Herein, we demonstrate a Q-switched Tm:Ho co-doped fiber laser centered at 2 µm, where the Ag/MXene composite serves as a saturable absorber to generate pulses. The typical spectrum, pulse train, and radio frequency spectrum of Q-switched pulses were observed, in which the 60 dB signal-to-noise ratio was higher than that of 2 µm Q-switched fiber lasers based on other materials, demonstrating the stability of the output pulses. Additionally, the long-term stability of the laser was evaluated over 2 h, where the well-maintained central wavelength and output power also indicated the robustness of the Q-switched laser. Furthermore, the influence of the pump power on the parameters of Q-switched pulses was also investigated, which is conducive to control the output characteristics of lasers. Specifically, the pulse width of the Q-switched pulse decreased, while the repetition rate, output power, and single pulse energy all increased with the increase in pump power. These experimental results demonstrate the ability of Ag/MXene as a saturable absorber and show its potential for generating high-performance pulses in ultrafast lasers. [ABSTRACT FROM AUTHOR]