Paecilomyces variotii extract "ZhiNengCong" (ZNC) has been confirmed to be a high activity plant immune inducer, but its application effect and appropriate concentration in different crops and ...different environmental conditions need to be further verified. This study set up six treatments, including three ZNC concentration levels (0, 5, and 20 ng/mL) and two Ralstonia solanacearum (Rs) inoculation levels (with and without), to explore the effect of ZNC application on the growth and disease resistance of peppers. The results showed that ZNC application (particularly 5 ng/mL ZNC) increased the basal biomass of the pepper plant and promoted root growth. 5 ng/mL ZNC can improve photosynthetic performance (net photosynthetic rate, transpiration rate and chlorophyll content averagely increased 20.2%, 33.7% and 16.0%, respectively) and antioxidant enzyme activities (particularly, catalase activity averagely increased 38.9%) of peppers more efficient than 20 ng/mL. Moreover, 5 ng/mL ZNC significantly increased Rs resistance of pepper, while 20 ng/mL ZNC did not show this effect. In conclusion, 5 ng/mL ZNC had the most significant effects on the growth-promoting and disease resistance of peppers, indicating good application prospects in agricultural practice.
Reversed conductance decay describes increasing conductance of a molecular chain series with increasing chain length. Realizing reversed conductance decay is an important step toward making long and ...highly conducting molecular wires. Recent work has shown that one-dimensional topological insulators (1D TIs) can exhibit reversed conductance decay due to their nontrivial edge states. The Su–Schrieffer–Heeger (SSH) model for 1D TIs relates to the electronic structure of these isolated molecules but not their electron transport properties as single-molecule junctions. Herein, we use a tight-binding approach to demonstrate that polyacetylene and other diradicaloid 1D TIs show a reversed conductance decay at the short chain limit. We explain these conductance trends by analyzing the impact of the edge states in these 1D systems on the single-molecule junction transmission. Additionally, we discuss how the self-energy from the electrode-molecule coupling and the on-site energy of the edge sites can be tuned to create longer wires with reversed conductance decays.
Transparent MgO ceramics are successful fabricated via spark plasma sintering at lower temperature using the high sintering activity powders synthesized by precipitated method. The samples were ...detected by XRD, SEM, TEM, BET, UV‐Vis‐NIR, microhardness, and so on. The results show that all ceramics prepared at 700°C‐900°C are visually transparent and the sample sintered at 860°C for 5 min exhibits the superior transmittance of 60% (800 nm). It is also found that the mechanical and thermal properties of MgO ceramics are all increasing firstly and then decreasing with the increase in the sintering temperature. And the maximum value of hardness, fracture toughness, MSP strength, and Young's modulus of MgO ceramics is 8.25 GPa, 2.01 MPa·m1/2, 206 MPa, and 286 GPa, respectively. Moreover, the thermal conductivity of MgO ceramics sintered at 860°C can reach 48.4 W/mK at room temperature.
The biophysical mechanism of the magnetic compass sensor in migratory songbirds is thought to involve photo-induced radical pairs formed in cryptochrome (Cry) flavoproteins located in photoreceptor ...cells in the eyes. In Cry4a-the most likely of the six known avian Crys to have a magnetic sensing function-four radical pair states are formed sequentially by the stepwise transfer of an electron along a chain of four tryptophan residues to the photo-excited flavin. In purified Cry4a from the migratory European robin, the third of these flavin-tryptophan radical pairs is more magnetically sensitive than the fourth, consistent with the smaller separation of the radicals in the former. Here, we explore the idea that these two radical pair states of Cry4a could exist in rapid dynamic equilibrium such that the key magnetic and kinetic properties are weighted averages. Spin dynamics simulations suggest that the third radical pair is largely responsible for magnetic sensing while the fourth may be better placed to initiate magnetic signalling particularly if the terminal tryptophan radical can be reduced by a nearby tyrosine. Such an arrangement could have allowed independent optimization of the essential sensing and signalling functions of the protein. It might also rationalize why avian Cry4a has four tryptophans while Crys from plants have only three.
Understanding how molecular geometry affects the electronic properties of single-molecule junctions experimentally has been challenging. Typically, metal–molecule–metal junctions are measured using a ...break-junction method where electrode separation is mechanically evolving during measurement. Here, to probe the impact of the junction geometry on conductance, we apply a sinusoidal modulation to the molecular junction electrode position. Simultaneously, we probe the nonlinearity of the current–voltage characteristics of each junction through a modulation in the applied bias at a different frequency. In turn, we show that junctions formed with molecules that have different molecule–electrode interfaces exhibit statistically distinguishable Fourier-transformed conductances. In particular, we find a marked bias dependence for the modulation of junctions where transmission is mediated thorough the van der Waals (vdW) interaction. We attribute our findings to voltage-modulated vdW interactions at the single-molecule level.
Flow field-flow fractionation (FlFFF) is a gentle technique that does not require a stationary phase and allows for the non-destructive isolation/separation of biomacromolecules and bioparticulate ...species in biological samples. Given the large separation range (i.e., 1 nm to 100 μm), FlFFF is theoretically applicable for the full spectrum of vital biological species. We provide an overview of the basic separation mechanism and development of FlFFF, followed by discussion of the current applications of FlFFF in the characterization of representative biomacromolecules, bionanoparticles, and biomicroparticles in biological samples, particularly new advances in the last 5 years. Furthermore, the emerging applications of FlFFF in extracellular vesicle research are systematically discussed for the first time. Finally, we posit that more efforts are needed to direct the separation and characterization of biomacromolecules, bionanoparticles, and biomicroparticles using FlFFF. Overall, this review provides current status, developmental trends, and further advances of FlFFF in life science.
•Full-spectrum separation of biological species by two FlFFF separation modes.•The potential of FlFFF in disease diagnosis and treatment.•Very recent use of FlFFF in the separation and characterization of EVs.•Some perspectives and future directions of FlFFF in life science.
Accurate determination of the heat release rate (HRR) information in ammonia flames is pivotal for practical applications of ammonia fuel in industrial combustion devices. However, the direct ...measurement of HRR in real-world applications is extremely challenging. In this study, we employed numerical simulation with detailed chemistry to assess the potential of using excited-state species and combinations of excited-state and ground-state species as HRR markers in laminar premixed ammonia–hydrogen–air flames. Two criteria were defined to evaluate the performance of the targeted HRR markers. The study revealed that single excited-state species generally exhibited limited performance as HRR markers, particularly in predicting both the peak location and the width of HRR profiles over a wide range of conditions. Products of two species showed improved performance; specifically, O2 *NH2 *, NH2NO2 *, and NH2NH2 * exhibited excellent performance in predicting both the peak position and width of HRR profiles across a broad range of flame conditions. Further improvements were observed with products of three species, as NH2O2 *NH2 * and NH2O2 *OH* performed well in marking both the peak location and the width of HRR profiles across various conditions. The integrated products of the concentration for NH2NH2 *, O2 *NH2 *, NH2O2 *NH2 *, and NH2O2 *OH* showed positive correlations with integrated HRR intensity under lean conditions, suggesting their potential use for indirectly inferring HRR intensity of practical combustion devices operating under lean conditions. Challenges associated with measurements of O2 * and the rationale behind the utilization of excited-state radicals as HRR markers are also discussed.
Global warming has posed significant pressure on agricultural productivity. The resulting abiotic stresses from high temperatures and drought have become serious threats to plants and subsequent ...global food security. Applying nanomaterials in agriculture can balance the plant’s oxidant level and can also regulate phytohormone levels and thus maintain normal plant growth under heat and drought stresses. Nanomaterials can activate and regulate specific stress-related genes, which in turn increase the activity of heat shock protein and aquaporin to enable plants’ resistance against abiotic stresses. This review aims to provide a current understanding of nanotechnology-enhanced plant tolerance to heat and drought stress. Molecular mechanisms are explored to see how nanomaterials can alleviate abiotic stresses on plants. In comparison with organic molecules, nanomaterials offer the advantages of targeted transportation and slow release. These advantages help the nanomaterials in mitigating drought and heat stress in plants.
This study evaluates the precision of widely recognized quantum chemical methodologies, CCSD(T), DLPNO–CCSD(T), and localized ph-AFQMC, for determining the thermochemistry of main group elements. ...DLPNO–CCSD(T) and localized ph-AFQMC, which offer greater scalability compared to canonical CCSD(T), have emerged over the past decade as pivotal in producing precise benchmark chemical data. Our investigation includes closed-shell, neutral molecules, focusing on their heat of formation and atomization energy sourced from four specific small molecule data sets. First, we selected molecules from the G2 and G3 data sets, noted for their reliable experimental heat of formation data. Additionally, we incorporate molecules from the W4–11 and W4–17 sets, which provide high-level theoretical reference values for atomization energy at 0 K. Our findings reveal that both DLPNO–CCSD(T) and ph-AFQMC methods are capable of achieving a root-mean-square deviation of less than 1 kcal/mol across the combined data set, aligning with the threshold for chemical accuracy. Moreover, we make efforts to confine the maximum deviations within 2 kcal/mol, a degree of precision that significantly broadens the applicability of these methods in fields such as biology and materials science.
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