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Flavonoids are by far the largest class of polyphenols with huge structural and functional diversity. However, the mystery regarding the exact evolutionary pressures which lead to the amazing diversity in plant flavonoids has yet to be completely uncovered. Here we review recent advances in understanding the conservation and diversification of flavonoid pathway from algae and early land plants to vascular plants including the model plant Arabidopsis and economically important species such as cereals, legumes, and medicinal plants. Studies on the origin and evolution of R2R3-MYB regulatory system demonstrated its highly conserved function of regulating flavonoid production in land plants and this innovation appears to have been crucial in boosting the overall levels of these compounds in land plants. Convergent evolution has occurred as different flavonoids independently which emerged in distant taxa resulting in similar defense and tolerance characteristics against environmental stresses. Future studies on an increasing number of plant species taking advantage of newly developed genomic and metabolite profiling technologies are envisaged to provide comprehensive insight into flavonoid biosynthesis as well as pathway diversification and the underlying evolutionary mechanisms. [ABSTRACT FROM AUTHOR]

A recent study by Butelli et al. (Curr. Biol. 2019;29:158–164) has demonstrated that the linked traits of exceptionally low fruit acidity and the absence of anthocyanins in leaves and flowers and proanthocyanidins in seeds of the citrus are the result of mutations in the Noemi gene encoding a bHLH transcription factor. [ABSTRACT FROM AUTHOR]

The adoption of recombinant inbred line and introgression line populations, as well as the study of association mapping panels, has greatly accelerated our ability to identify the genes underlying plant phenotypic variance. In tandem, the development of metabolomics approaches has greatly enhanced our ability to comprehensively define cellular chemical composition. As a consequence, breeding for chemical composition is being extended beyond our traditional targets of oil and protein to include components such as essential amino acids, vitamins, and antioxidant secondary metabolites with considerable purported consequences for human health. Here, we review the above-mentioned developments paying particular attention to the genetic architecture of metabolic traits as well as updating the perspective for utilizing metabolomics in maize improvement. [ABSTRACT FROM AUTHOR]

In this paper, homogeneous composites of pomegranate-structured SnO 2 @C/Cu have been prepared by a simple hydrothermal reaction coupled with wet-chemical reduction, and directly used as anode materials for lithium ion batteries (LIBs). These SnO 2 @C/Cu anodes with an unique architecture show good LIB performance with a capacity of 660 mAh g −1 tested at 600 mA g −1 after 50 cycles and good rate performance at room temperature. Compared with the pure SnO 2 and SnO 2 @C, SnO 2 @C/Cu anodes exhibit much better low-temperature electrochemical performance including reversible capacity, cycling performance, and rate performance. The good LIB performance of SnO 2 @C/Cu anodes should be associated with carbon shell and the conducting Cu particles. This unique configuration can prevent the agglomeration of active materials and facilitate electron conduction especially at a relative low temperature, and obtain the capacity stability in cycling process for LIBs. [ABSTRACT FROM AUTHOR]

The poor conductivity of anodic carbon materials at low temperature hampers their high-level applications in Li ion batteries (LIBs). Introducing some reliable metals with good electrical conductivity into anodes could alleviate these problems. In this work, the novel composites of Fe-added Fe 3 C carbon nanofibers (Fe/Fe 3 C CNFs) were synthesized via facile electrospinning method and used as anode materials for LIBs. The resulting anodes with Fe/Fe 3 C CNF materials exhibited a high reversible capacity of 500 mAh g −1 tested at 200 mA g −1 even after 70 cycles and excellent performance at room temperature. Importantly, it delivered a high capacity of 250 mAh g −1 at 400 mA g −1 even after 55 cycles at a low temperature of −15 °C. The superior low-temperature electrochemical performance of the Fe/Fe 3 C CNF anodes is associated with an improved effect of the highly conducting Fe at low temperature. [ABSTRACT FROM AUTHOR]

The majority of the crops and vegetables of today were domesticated from their wild progenitors within the past 12 000 years. Considerable research effort has been expended on characterizing the genes undergoing positive and negative selection during the processes of crop domestication and improvement. Many studies have also documented how the contents of a handful of metabolites have been altered during human selection, but we are only beginning to unravel the true extent of the metabolic consequences of breeding. We highlight how crop metabolomes have been wittingly or unwittingly shaped by the processes of domestication, and highlight how we can identify new targets for metabolite engineering for the purpose of de novo domestication of crop wild relatives. Next-generation sequencing has dramatically boosted our ability to study selection during domestication and crop improvement. Domestication of our crop species is characterized by a reduction in allelic diversity and massive changes in both their gene expression and visible phenotype. An increasing number of studies suggest that metabolism is also considerably affected. However, in contrast to gene expression changes which are largely conserved, changes at the level of the metabolome appear to be species-specific. [ABSTRACT FROM AUTHOR]

Composites of Ag-incorporated carbon nanofibers (CNFs) confined with Fe 2 O 3 nanoparticles (Ag–Fe 2 O 3 /CNFs) have been synthesized through an electrospinning method and evaluated as anodes for lithium batteries (LIBs). The obtained Ag–Fe 2 O 3 /CNF anodes show good LIB performance with a capacity of 630 mAh g −1 tested at 800 mA g −1 after 150 cycles with almost no capacity loss and superb rate performance. The obtained properties for Ag–Fe 2 O 3 /CNF anodes are much better than Fe 2 O 3 /CNF anodes without Ag-incorporating. In addition, the low-temperature LIB performances for Ag–Fe 2 O 3 /CNF anodes have been investigated for revealing the enhanced mechanism of Ag-incorporating. The superior electrochemical performances of the Ag–Fe 2 O 3 /CNFs are associated with a synergistic effect of the CNF matrix and the highly conducting Ag incorporating. This unique configuration not only facilitates electron conduction especially at a relative temperature, but also maintains the structural integrity of active materials. Meanwhile, the related analysis of the AC impedance spectroscopy and the corresponding hypothesis for DC impedance confirm that such configuration can effectively enhance the charge-transfer efficiency and the lithium diffusion coefficient. Therefore, CNF-supported coupled with Ag incorporating synthesis supplied a promising route to obtain Fe 2 O 3 based anodes with high-performance LIBs especially at low temperature. [ABSTRACT FROM AUTHOR]

Free-standing paper of N-doped carbon nanofibers (NCNFs) containing SnO x was prepared by electrospinning. The structure and morphology of the sample were analyzed by XRD, XPS, SEM, and TEM. The results show that nitrogen atoms were successfully doped into CNFs. The SnO x were homogenously embedded in the N-doped CNFs via annealing treatment. Subsequently, the SnO x NCNF paper was cut into disks and used as anodes for lithium ion batteries (LIBs). The anodes of SnO x NCNFs exhibit excellent cycling stability and show high capacity of 520 mA h g −1 tested at a 200 mA g −1 after 100 cycles. More importantly, at a high current density of 500 mA g −1 , a large reversible capacity of 430 mA h g −1 after 100 cycles can still be obtained. The good electrochemical performance should be attributed to the good electronic conductivity from the NCNFs and the synergistic effects from NCNFs and SnO x materials. [ABSTRACT FROM AUTHOR]

In order to accurately predict the variation rule of the effective permittivity and component content of silicon carbide (SiC) composites, the dielectric constants of SiC nano-particulate and its composites have been investigated by experiments and theoretical calculation. Based on the measured relative effective permittivity of samples with different SiC concentration, a calculation method for effective permittivity was established by modifying effective medium formula and Debye model. By the proposed formulas, the intrinsic permittivity of SiC versus frequency was revealed. The effective permittivity of SiC composites as a function of filling content and frequency was also explored. The relative deviation between the theoretical values and the experimental data was less than 5%. The frequency dispersion characteristic of the dielectric parameters of the component as well as the effect of the fillers on the depolarization field of the composite system was fully taken into consideration during the effective permittivity model establishing. Therefore the proposed effective permittivity model should be suitable for both low-filling and high-filling concentration systems. • It is difficult to measure the permittivity of powdery materials in the microwave band directly. Considering the frequency dispersion characteristic of the dielectric parameters of filling component and the effect of the fillers on the depolarization field of the composite, a proposed calculation method for effective permittivity of SiC/matrix composite is established by modifying effective medium formula and Debye model.. • Considering the interaction between the absorbent particles and the effect of particles on the depolarization field inside the medium, the formula for effective permittivity is deduced by area search algorithm to explore the unknown parameters. This process makes the formula more consistent with the experimental data. The proposed formula is available in the conditions of both high-filling and low-filling concentration. • According to the microscopic dielectric properties of components, the proposed formula for intrinsic permittivity is established on the basis of Debye model. Then the dielectric parameters of SiC with frequency are explored. The effective permittivity of SiC/paraffin composite calculated by the proposed formulas has a good agreement with the measured data, and the relative deviation at each frequency is below 5%.. [ABSTRACT FROM AUTHOR]

• A navel orange mutant 'Gannan No.1' has higher biomembrane stability and fruit quality during storage. • Higher unsaturation degree of fatty acids contributes to the membrane stability of citrus fruit. • The ascorbic acid-glutathione-tocopherol triad contributes to the anti-peroxidation of membrane lipids in citrus fruit. Little is known about the variations of fresh fruit biomembrane and its physiological and biochemical characteristics during storage. A navel orange mutant 'Gannan No.1' (Citrus sinensis Osbeck) showed higher membrane stability and titratable acid while lower calyx senescence compared with wild-type 'Newhall'. The membrane damage was significantly reduced in 'Gannan No.1' under 10% polyethylene-glycol (41.16% vs. 8.77%) and 30% polyethylene-glycol (52.59% vs. 16.11%) treatments on day 45 after harvest. Consistently, membrane electrolyte leakage and malondialdehyde were significantly decreased in 'Gannan No.1', and superoxide dismutase and glutathione reductase were activated. A metabolic analysis was performed to evaluate membrane fatty acid unsaturation and peroxidation. Linolenic acid and hexadecylenic acid contributed to the higher degree of unsaturated fatty acids in 'Gannan No.1'. Furthermore, 'Gannan No.1' accumulated stress-resistant metabolites such as proline, α-tocopherol and glutathione. Correlation analysis of membrane homeostasis indexes with quality parameters showed the importance of biomembrane stability in maintaining citrus fruit quality. [ABSTRACT FROM AUTHOR]

An effective standoff alpha radiation measurement of surface contamination method is of great importance in radioactive waste disposal and decommissioning of nuclear facilities, nuclear accident emergency response and nuclear security. Here, we build an optical system for the implementation of standoff alpha radiation measurement based on radioluminescence. We present the results of the detection efficiency calibrating of standoff alpha radioactive sources using simulation and experiment. At the same time, a numerical integration-based surface contamination measurement method is designed, computed, and validated through experiments and simulations. Finally, the minimum detectable surface activity of the method is given for different measurement conditions. • A model for standoff alpha radiation measurement based on radioluminescence. • The validity of the MC simulated detector model was verified by experiments. • The performance of device is expressed in terms of MDSA under different conditions. [ABSTRACT FROM AUTHOR]

The α-particle detection has a pivotal role in radiation measurement. Standoff α-particle detection has advantages such as high efficiency and safety compared with the traditional method. However, the low yield of the characteristic signal significantly limits the broad application of this technique. To efficiently perform standoff detection of α-particle, the physical mechanism of α-particle interaction with air, the various secondary effects generated, and the yields are systematically analyzed in this paper. The results show that in addition to the radioluminescence, which is the focus of most current studies, the characteristic X-rays also meet the requirements as a characteristic signal for standoff detection. The processes of induced generation of these two secondary particles in the air are studied, the yields of characteristic X-rays of nitrogen and oxygen atoms and the yields of radioluminescence photons in the near-ultraviolet (UVA/UVB) and deep-ultraviolet (UVC) bands are given, respectively. The interference brought by the presence of β-particles and γ-particles to the α-detection when the radiation field is more complex is also quantitatively analyzed. • Standoff α-ray detection is possible based on characteristic X-rays and radioluminescence. • The characteristic X-ray yields of nitrogen and oxygen are calculated separately. • The radioluminescence yields of UVA/UVB and UVC photons are investigated separately. • The interference brought by β and γ rays to standoff α-ray detection is limited. [ABSTRACT FROM AUTHOR]