Ultrastrong spinodoid alloys enabled by electrochemical dealloying and refilling.

We present an extreme case of composition-modulated nanomaterial formed by selective etching (dealloying) and electrochemical refilling. The product is a coarse-grain polycrystal consisting of two interwoven nanophases, with identical crystal structures and a cube-on-cube relationship, separated by smoothly curved semicoherent interfaces with high-density misfit dislocations. This material resembles spinodal alloys structurally, but its synthesis and composition modulation are spinodal-independent. Our Cu/Au "spinodoid" alloy demonstrates superior mechanical properties such as near-theoretical strength and single-phase-like behavior, owing to its fine composition modulation, large-scale coherence of crystal lattice, and smoothly shaped three-dimensional (3D) interface morphology. As a unique extension of spinodal alloy, the spinodoid alloy reported here reveals a number of possibilities to modulate the material's structure and composition down to the nanoscale, such that further improved properties unmatchable by conventional materials can be achieved.

Temperature-Automated Calibration Methods for a Large-Area Blackbody Radiation Source.

High-precision temperature control of large-area blackbodies has a pivotal role in temperature calibration and thermal imaging correction. Meanwhile, it is necessary to correct the temperature difference between the radiating (surface of use) and back surfaces (where the temperature sensor is installed) of the blackbody during the testing phase. Moreover, large-area blackbodies are usually composed of multiple temperature control channels, and manual correction in this scenario is error-prone and inefficient. At present, there is no method that can achieve temperature-automated calibration for a large-area blackbody radiation source. Therefore, this article is dedicated to achieving temperature-automated calibration for a large-area blackbody radiation source. First, utilizing two calibrated infrared thermometers, the optimal temperature measurement location was determined using a focusing algorithm. Then, a three-axis movement system was used to obtain the true temperature at the same measurement location on a large-area blackbody surface from different channels. This temperature was subtracted from the blackbody's back surface. The temperature difference was calculated employing a weighted algorithm to derive the parameters for calibration. Finally, regarding experimental verification, the consistency error of the temperature measurement point was reduced by 85.4%, the temperature uniformity of the surface source was improved by 40.4%, and the average temperature measurement deviation decreased by 43.8%. In addition, this system demonstrated the characteristics of strong environmental adaptability that was able to perform temperature calibration under the working conditions of a blackbody surface temperature from 100 K to 573 K, which decreased the calibration time by 9.82 times.

Integrated Secondary Metabolomic and Antioxidant Ability Analysis Reveals the Accumulation Patterns of Metabolites in Momordica charantia L. of Different Cultivars.

Bitter gourd (Momordica charantia L.) contains rich bioactive ingredients and secondary metabolites; hence, it has been used as medicine and food product. This study systematically quantified the nutrient contents, the total content of phenolic acids (TPC), flavonoids (TFC), and triterpenoids (TTC) in seven different cultivars of bitter gourd. This study also estimated the organic acid content and antioxidative capacity of different cultivars of bitter gourd. Although the TPC, TFC, TTC, organic acid content, and antioxidative activity differed significantly among different cultivars of bitter gourd, significant correlations were also observed in the obtained data. In the metabolomics analysis, 370 secondary metabolites were identified in seven cultivars of bitter gourd; flavonoids and phenolic acids were significantly more. Differentially accumulated metabolites identified in this study were mainly associated with secondary metabolic pathways, including pathways of flavonoid, flavonol, isoflavonoid, flavone, folate, and phenylpropanoid biosyntheses. A number of metabolites (n = 27) were significantly correlated (positive or negative) with antioxidative capacity (r ≥ 0.7 and p < 0.05). The outcomes suggest that bitter gourd contains a plethora of bioactive compounds; hence, bitter gourd may potentially be applied in developing novel molecules of medicinal importance.

Artificial Light for Improving Tomato Recovery Following Grafting: Transcriptome and Physiological Analyses.

Grafting is widely used to enhance the phenotypic traits of tomatoes, alleviate biotic and abiotic stresses, and control soil-borne diseases of the scion in greenhouse production. There are many factors that affect the healing and acclimatization stages of seedlings after grafting. However, the role of light has rarely been studied. In this study, we compared the effects of artificial light and traditional shading (under shaded plastic-covered tunnels) on the recovery of grafted tomato seedlings. The results show that the grafted tomato seedlings recovered using artificial light had a higher healthy index, leaf chlorophyll content, shoot dry weight, and net photosynthetic rate (Pn) and water use efficiency (WUE) compared with grafted seedling recovered using the traditional shading method. Transcriptome analysis showed that the differentially expressed genes (DEGs) of grafted seedlings restored using artificial light were mainly enriched in the pathways corresponding to plant hormone signal transduction. In addition, we measured the endogenous hormone content of grafted tomato seedlings. The results show that the contents of salicylic acid (SA) and kinetin (Kin) were significantly increased, and the contents of indoleacetic acid (IAA) and jasmonic acid (JA) were decreased in artificial-light-restored grafted tomato seedlings compared with those under shading treatments. Therefore, we suggest that artificial light affects the morphogenesis and photosynthetic efficiency of grafted tomato seedlings, and it can improve the performance of tomato seedlings during grafting recovery by regulating endogenous hormone levels.

Transcriptional regulation of proanthocyanidin biosynthesis pathway genes and transcription factors in Indigofera stachyodes Lindl. roots.

BACKGROUND: Proanthocyanidins (PAs) have always been considered as important medicinal value component. In order to gain insights into the PA biosynthesis regulatory network in I. stachyodes roots, we analyzed the transcriptome of the I. stachyodes in Leaf, Stem, RootI (one-year-old root), and RootII (two-year-old root). RESULTS: In this study, a total of 110,779 non-redundant unigenes were obtained, of which 63,863 could be functionally annotated. Simultaneously, 75 structural genes that regulate PA biosynthesis were identified, of these 6 structural genes (IsF3'H1, IsANR2, IsLAR2, IsUGT72L1-3, IsMATE2, IsMATE3) may play an important role in the synthesis of PAs in I. stachyodes roots. Furthermore, co-expression network analysis revealed that 34 IsMYBs, 18 IsbHLHs, 15 IsWRKYs, 9 IsMADSs, and 3 IsWIPs hub TFs are potential regulators for PA accumulation. Among them, IsMYB24 and IsMYB79 may be closely involved in the PA biosynthesis in I. stachyodes roots. CONCLUSIONS: The biosynthesis of PAs in I. stachyodes roots is mainly produced by the subsequent pathway of cyanidin. Our work provides new insights into the molecular pathways underlying PA accumulation and enhances our global understanding of transcriptome dynamics throughout different tissues.

Comparative Metabolomics study of flavonoids in the pericarp of different coloured bitter gourds (Momordica charantia L.).

Bitter gourd (Momordica charantia L.) is a member of Cucurbitaceae family and has long been used as a source of food and medicine for its rich bioactive components or secondary metabolites. However, there are relatively few large-scale detection, identification, and quantitative studies on flavonoids in the pericarp of bitter gourds of different colours. To determine the differences in the diversity and specificity of flavonoids in the pericarp of bitter gourd of different colours, the metabolic profiles in the pericarp of three coloured bitter gourd accessions, dark green (mo), pale green (lv), and white (bai), were analysed by ultra-performance liquid chromatography-tandem mass spectrometry. Priorly, it was confirmed that the different shades of green were caused by the content of chlorophyll. A total of 93 metabolites, including 90 flavonoids and three tannins, were detected in the current study. These 90 flavonoids included three isoflavones, nine dihydroflavones, seven flavanols, 34 flavonols, 26 flavonoids, four chalcones, five flavonoid carbonosides, and two dihydroflavonols. Compared to mo, both lv and bai had 21 and 25 different metabolites, respectively, while there were only nine different metabolites between lv and bai. The relative contents of vitexin and isovitexin increased with the deeper colour of the bitter gourd. Thus, the different metabolites in coloured bitter gourds are mainly involved in the biosynthesis of flavonols, flavonoid carbonosides, and flavonoids. This study enables identification of metabolic differences in the pericarp of bitter gourds of different colours. The results will be helpful for quality breeding of new bitter gourd varieties and shall provide a reference for their medical application. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-022-01210-7.

Surface Triple Junctions Govern the Strength of a Nanoscale Solid.

Surface triple junctions (STJs), i.e., the termination lines of grain boundaries at solid surface, are the common line defects in polycrystalline materials. Compared with planar defects such as grain boundaries and surfaces, STJ lines are usually overlooked in a material's strengthening although abundant atoms may reside at STJs in many nanomaterials. In this study, by in situ compression of coarse-grained and nanocrystalline nanoporous gold samples in an electrochemical environment, the effect of STJs on the strength of nanoporous gold was successfully decoupled from grain-boundary and surface effects. We found that the strength of nanoporous gold became sensitive to STJ modification when ligament size was decreased to below ∼100 nm, indicating that STJs started to influence ligament strength at sub-100 nm scale. This STJ effect was associated with the emission of dislocations from STJs during plastic deformation. Our findings strongly suggest that the structure and chemistry at STJs should be considered in understanding the mechanical response of sub-100 nm scale materials.

Transition from Homogeneous to Localized Deformation in Nanoporous Gold.

We report a transition from homogeneous deformation to localized densification for nanoporous gold (NPG) under compression, with its solid fraction (φ) increasing to above ∼1/3. Results obtained herein suggest that this transition is inverted compared to that of conventional porous materials. Consequently, under compression, the low-density NPGs with φ<1/3 showed evident strain hardening, whereas a stress plateau was observed for high-density NPGs with φ>1/3, which is contrary to the established notions for conventional porous materials. The ligament pinch-offs and bending-dominated structures are responsible for the homogeneous deformation of low-density NPGs. For high-density NPGs, the compression- or tension-dominated structure enables the collective strain bursts in nanoligaments, resulting in localized densification and stress plateau in their compression curves. In addition to the nanosize effect, the surface-diffusion-mediated topology evolution and the large-scale crystal-lattice coherency arising from the large grain size are also decisive to the mechanical response of dealloyed NPGs, which might be universal for self-organized nanonetwork materials.

Comparative Proteomic Analysis of Dipsacus asperoides Roots from Different Habitats in China.

Dipsacus asperoides is a kind of Chinese herbal medicine with beneficial health properties. To date, the quality of D. asperoides from different habitats has shown significant differences. However, the molecular differences in D. asperoides from different habitats are still unknown. The aim of this study was to investigate the differences in protein levels of D. asperoides from different habitats. Isobaric tags for relative and absolute quantification (iTRAQ) and 2DLC/MS/MS were used to detect statistically significant changes in D. asperoides from different habitats. Through proteomic analysis, a total of 2149 proteins were identified, of which 42 important differentially expressed proteins were screened. Through in-depth analysis of differential proteins, the protein metabolism energy and carbohydrate metabolism of D. asperoides from Hubei Province were strong, but their antioxidant capacity was weak. We found that three proteins, UTP-glucose-1-phosphate uridylyltransferase, allene oxide cyclase, and isopentyl diphosphate isomerase 2, may be the key proteins involved in dipsacus saponin VI synthesis. Eight proteins were found in D. asperoides in response to environmental stress from different habitats. Quantitative real-time PCR analysis confirmed the accuracy and authenticity of the proteomic analysis. The results of this study may provide the basic information for exploring the cause of differences in secondary metabolites in different habitats of D. asperoides and the protein mechanism governing differences in quality.

Size-Dependent Grain-Boundary Structure with Improved Conductive and Mechanical Stabilities in Sub-10-nm Gold Crystals.

Low-angle grain boundaries generally exist in the form of dislocation arrays, while high-angle grain boundaries (misorientation angle >15°) exist in the form of structural units in bulk metals. Here, through in situ atomic resolution aberration corrected electron microscopy observations, we report size-dependent grain-boundary structures improving both stabilities of electrical conductivity and mechanical properties in sub-10-nm-sized gold crystals. With the diameter of a nanocrystal decreasing below 10 nm, the high-angle grain boundary in the crystal exists as an array of dislocations. This size effect may be of importance to a new generation of interconnects applications.

Sealing-free fast-response paraffin/nanoporous gold hybrid actuator.

Paraffin-based actuators can deliver large actuation strokes and high actuation stress, but often suffer from a low response rate and leaking problems. Here, we report a new paraffin/metal hybrid actuator, which was fabricated by infiltrating nanoporous gold with paraffin. It exhibits a fast actuation rate owing to the high thermal conductivity of the inter-connected metal phase, and requires no external sealing because liquid paraffin can be well confined in nanoscale channels, due to the large capillarity. We found that in this hybrid actuator, the stress generated by actuation is negligibly small when the characteristic size of the nanoporous gold (L) is above ∼70 nm, and increases dramatically with a decreasing size when L < âˆ¼70 nm. The large actuation stress in samples with L < âˆ¼70 nm is ascribed to a 'smaller is stronger' effect in paraffin wax-the paraffin in smaller pores can sustain larger tensile stress, and thus the contraction of paraffin during cooling can be translated into larger compression stress and strain energy in a metal framework, leading to a larger actuation stress and energy. We also demonstrate that complex actuation motions can be achieved by incorporating hierarchical-structured nanoporous metal with paraffin.

Anomalous low strain induced by surface charge in nanoporous gold with low relative density.

The surface stress induced axial strain in a fiber-like solid is larger than its radical strain, and is also greater than the radical strain in similar-sized spherical solids. It is thus envisaged that the surface-induced macroscopic dimension change (i.e., actuation strain) in nanoporous gold (NPG) increases with decreasing relative density, or alternatively, with an increasing ratio between volumes of fiber-like ligaments and sphere-like nodes. In this study, electrochemical actuations of NPG with similar structure sizes, same (oxide-covered) surface state but different relative densities were characterized in situ in response to surface charging/discharging. We found that the actuation strain amplitude did not increase, but decreased dramatically with decreasing relative density of NPG, in contrast to the above prediction. The actuation strain decreased abruptly when the relative density of NPG was decreased to below 0.25, when the Au content in the AuAg precursor was below 20 at%. Further studies indicate that this anomalous behavior cannot be explained by potential- or size-dependences of the elasticity, the structure difference arising from different dealloying rates, or additional strain induced by the external load during dilatometry experiments. In NPG with low relative density, mutual movements of nano-ligaments may occur in the pore space and disconnected regions, which may compensate the local strain in ligaments and account for the anomalous low actuation strain in macroscopic NPG samples.

Responsive nanoporous metals: recoverable modulations on strength and shape by watering.

Many biological materials can readily modulate their mechanical properties and shape by interacting with water in the surrounding environment, which is essential to their high performance in application. In contrast, typical inorganic materials (such as the metals) cannot change their strength and shape without involving thermal/mechanical treatments. By introducing nano-scale porous structure and exploiting a simple physical concept-the water-capillarity in nanopores, here we report that a 'dead' metal can be transformed into a 'smart' material with water-responsive properties. We demonstrate that the apparent strength, volume and shape of nanoporous Au and Au(Pt) can be modulated in situ, dramatically and recoverably, in response to water-dipping and partial-drying. The amplitude of strength-modulation reaches 20 MPa, which is nearly 50% of the yield strength at initial state. This approach also leads to reversible length change up to 1.3% in nanoporous Au and a large reversible bending motion of a bi-layer strip with tip displacement of ∼20 mm, which may be used for actuation. This method is simple and effective, occurring in situ under ambient conditions and requiring no external power, analogous to biological materials. The findings may open up novel applications in many areas such as micro-robotics and bio-medical devices.

Effects of Light Intensity on Growth and Quality of Lettuce and Spinach Cultivars in a Plant Factory.

The decreased quality of leafy vegetables and tipburn caused by inappropriate light intensity are serious problems faced in plant factories, greatly reducing the economic benefits. The purpose of this study was to comprehensively understand the impact of light intensity on the growth and quality of different crops and to develop precise lighting schemes for specific cultivars. Two lettuce (Lactuca sativa L.) cultivars-Crunchy and Deangelia-and one spinach (Spinacia oleracea L.) cultivar-Shawen-were grown in a plant factory using a light-emitting diode (LED) under intensities of 300, 240, 180, and 120 µmol m-2 s-1, respectively. Cultivation in a solar greenhouse using only natural light (NL) served as the control. The plant height, number of leaves, and leaf width exhibited the highest values under a light intensity of 300 µmol m-2 s-1 for Crunchy. The plant width and leaf length of Deangelia exhibited the smallest values under a light intensity of 300 µmol m-2 s-1. The fresh weight of shoot and root, soluble sugar, soluble protein, and ascorbic acid contents in the three cultivars increased with the increasing light intensity. However, tipburn was observed in Crunchy under 300 µmol m-2 s-1 light intensity, and in Deangelia under both 300 and 240 µmol m-2 s-1 light intensities. Shawen spinach exhibited leaf curling under all four light intensities. The light intensities of 240 and 180 µmol m-2 s-1 were observed to be the most optimum for Crunchy and Deangelia (semi-heading lettuce variety), respectively, which would exhibit relative balance growth and morphogenesis. The lack of healthy leaves in Shawen spinach under all light intensities indicated the need to comprehensively optimize cultivation for Shawen in plant factories to achieve successful cultivation. The results indicated that light intensity is an important factor and should be optimized for specific crop species and cultivars to achieve healthy growth in plant factories.

Identification and characterization of miRNAome and target genes in Pseudostellaria heterophylla.

miRNAs play a crucial role in the development and growth of plants by inhibiting the function of targeted genes at the post-transcription level. However, no miRNAs in Pseudostellaria heterophylla have been reported and their function in the morphogenesis of organs is still unclear. In this study, a total of 159 conserved miRNAs (belonging to 64 families) and 303 level miRNAs were identified from P. heterophylla. Some of them showed specifically up or down-regulated expression in different tissues and numbers of unigenes involved in Plant-pathogen interaction and MAPK signaling pathway-plant were targeted. The significant negative correlation of expression profiles between 30 miRNAs and their target genes (37 unigenes) was observed, respectively. Further, a large number of genes involved with signal transduction of auxin, zeatin, abscisic acid and, jasmonic acid were targeted. Predicated targets of two miRNAs were validated by 5'RLM-RACE, respectively. A large number of mRNAs from four pathogens were targeted by miRNAs from P. heterophylla and some of them were targeted by miR414. In summary, we reported a population of miRNAs from four different vegetative tissues of P. heterophylla by high throughput sequencing, which was analyzed by combining with the constructed transcriptome. These results may help to explain the function of miRNAs in the morphogenesis of organs and defense of pathogens, and may provide theoretical basis for breeding and genetic improvement of P. heterophylla.

Nutrient Concentrations Induced Abiotic Stresses to Sweet Pepper Seedlings in Hydroponic Culture.

The primary goal of this experiment was to investigate the effects of nutrient electrical conductivity (EC) on the growth and physiological responses of sweet pepper (Capsicum annuum L.) in hydroponic culture in a greenhouse. The plant growth parameters, leaf photosynthesis, root activity, soluble protein, malondialdehyde (MDA), proline, activities of antioxidant enzymes (AE), and the contents of plant mineral elements (PME) were measured in six different EC treatments. The results showed that very high or low EC treatments clearly decreased the plant height, stem diameter, shoot dry weight, and leaf net photosynthetic rate, while increasing the content of MDA and the activities of ascorbate peroxidase and guaiacol peroxidase. The contents of proline and soluble protein increased gradually from the low to high EC treatments. The root activities decreased significantly, and the main PME clearly did not increase or even decreased at high EC levels. Very high EC treatments suppressed growth even more than those of very low EC. Treatments that were too low or high EC suppressed plant growth, owing to abiotic stress (either nutrient deficiency or salinity), since the plants had to regulate the activities of AE and increase the accumulation of osmolytes to adjust to the abiotic stresses.

Integrated analysis of transcriptome and microRNAs associated with exogenous calcium-mediated enhancement of hypoxic tolerance in cucumber seedlings (Cucumis sativus L.).

Plants often suffer from hypoxic stress due to flooding caused by extreme weather. Hypoxia usually leads to restricted oxygen supply and alters metabolic patterns from aerobic to anaerobic. Cucumber roots are fragile and highly sensitive to damage from hypoxic stress. The purpose of this study was to investigate the regulatory mechanism of exogenous calcium alleviating hypoxic stress in cucumber through transcriptome and small RNAs analysis. Three treatments were performed in this paper, including untreated-control (CK), hypoxic stress (H), and hypoxic stress + exogenous calcium treatment (H + Ca2+). A large number of differentially expressed genes (DEGs) were identified, 1,463 DEGs between CK vs H, 3,399 DEGs between H vs H + Ca2+, and 5,072 DEGs between CK vs H + Ca2+, respectively. KEGG analysis of DEGs showed that exogenous calcium could activate hormone signaling pathways (ethylene, ABA, IAA and cytokinin), transcription factors (MYB, MYB-related, bHLH, bZIP, and WRKY), calcium signaling and glycolysis pathway to mitigating hypoxic stress in cucumber seedlings. Additionally, miRNA and their target genes were detected and predicted between treatments. The target genes of these miRNAs revealed that auxin, cellulose synthase, and mitochondrial ribosomal related genes (Csa2G315390, Csa6G141390, Csa4G053280, and Csa6G310480) probably play in the improvement of the hypoxic tolerance of cucumber seedlings through exogenous calcium application. In short, our data adds new information to the mechanism of exogenous calcium mitigation of hypoxic stress injury in cucumber seedlings at transcriptional and post-transcriptional levels.

Comparison of rockwool and coir for greenhouse cucumber production: chemical element, plant growth, and fruit quality.

Replacing rockwool with more sustainable materials, such as coir, is an effective measure to improve the sustainability of soilless cultivation in the greenhouse. To comprehensively assess the feasibility of coir before using it widely, coir was compared to rockwool as a cucumber cultivation substrate to evaluate its performance on mineral elements in the substrates, drainage, and in the plants. Plant growth, amino acids, and flavor substances of cucumber fruits were also compared between the two substrates. Compared to rockwool, coir significantly increased the LAI and yield of cucumber crops as well as contents of Ca, Mg, S, Cl and Zn in leaves and fruits. Contents of P, K, Ca, Mg, Cl, Zn, and B in the substrate were higher for coir while those of Fe, Cu, and Mn in the drainage lower. Moreover, coir also significantly increased contents of amino acids (His, Leu, Ile, Phe, Lys, Asp, Glu and Pro) and flavor substance (TC, PS, TP, CLL, CuB, and LA) in cucumber fruits. Our results demonstrated the potential of coir as a replacement of rockwool to improve sustainability of soilless cultivation in the greenhouse.

Zero Discharge of Nutrient Solution to the Environment in a Soilless Greenhouse Cucumber Production System.

With the development of the economy and society, more attention is being paid to energy costs and the potential environmental pollution caused by vegetable cultivation. The aim of this study was to investigate the impacts of zero discharge of nutrient solutions on cucumber growth, leaf photosynthesis, and the yield and quality of cucumber under greenhouse conditions. The results show that zero discharge treatment did not change plant height, stem diameter, internode length, leaf area, net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), and leaf relative chlorophyll content on the most measurement days. Only Pn and relative chlorophyll content were significantly reduced after 16 days of treatment but soon recovered over time. Cucumber plants can adapt to treatment circumstances over the course of days. Leaf mineral element contents showed significant differences on some treatment days compared to the control, and trace elements of Fe, Mn, Cu, and Mo can be appropriately supplied during the treatment days. The cucumber yield and fruit quality in the zero discharge treatment did not change during the whole experimental period. This study confirmed that the irrigation method of a nutrient solution with zero discharge can be applied in cucumber cultivation practices. The strict management of irrigation strategy, plant growth, and greenhouse climate are very important for zero discharge cultivation. The cultivation method with zero discharge of nutrient solution can reduce the energy costs of disinfection, save water and fertilizers, and reduce the environmental pollution in cucumber cultivation.

Nanoporous Au-Pt alloys as large strain electrochemical actuators.

Nanoporous Au-Pt alloys with pore- and ligament size down to few nanometers were fabricated by dealloying Ag-Au-Pt. Owing to the small structure size and large specific surface area, the surface stress and its variation give rise to significant stress and strain in the bulk of these materials. In fact, dilatometry experiments find electrochemical actuation with large reversible strain amplitude. The linear strain reaches approximately 1.3% and strain energy density is up to 6.0 MJ/m(3). The associated stresses may approach the elastic limit of the alloy.