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A g-C3N4 derivative containing heptazines merged with phenyls is synthesized from melamine and quinazoline-2,4(1H,3H)-dione and purified via vacuum sublimation, and then used as a high-efficiency metal-free quasi-green phosphor in white LEDs.

Herein, we describe a challenging organocatalytic asymmetric aza- Friedel–Crafts reaction of naphthols/phenols with cyclic-ketimines attached to neutral functional group, achieving enantiomerically enriched chiral aminonaphthols.

Herein, we describe a B(C6F5)3-catalyzed redox-neutral β-functionalization of tertiary amines with cyclic-ketimines, achieving various 1,3-diamines containing the indolin-3-one moiety via the borrowing hydrogen strategy.

A chiral phosphoric acid-catalyzed enantioselective aza-Friedel-Crafts reaction of 5-aminopyrazole derivatives with cyclic ketimines attached to a neutral functional group is reported. This protocol allows the formation of pyrazole-based C2-quaternary indolin-3-ones with high enantioselectivities and regioselectivities. Moreover, gram-scale synthesis of the 5-aminopyrazole-based C2-quaternary indolin-3-ones was performed, with no decrease in the yield and enantioselectivity.

The present paper is focused on the investigation of the correlation modeling of hardness and compressive residual stress on the surface and subsurface regions of case-hardened 18CrNiMo7-6 steels subjected to shot peening. The results exhibit that the relationship between hardness and compressive residual stress can reasonably well be approximated by an inverse linear model. The analysis suggests that the slope and y-intercept of the inverse linear trend line can be related to the compressive residual stress level and the initial material hardness, respectively. It is further revealed that the negative effect brought by the peening-induced roughness on the measurement of experimental data computed on the surface can be compensated by performing the normalization using the roughness parameter called the maximum valley height (Sv).

The enantioselective aza-Friedel-Crafts reaction is one of the most straightforward and efficient strategies for constructing a new carbon-carbon bond bearing quaternary stereocenter in organic synthesis, but the catalytic asymmetric aza-Friedel-Crafts reaction of naphthols/phenols with cyclic-ketimines attached to a neutral functional group remains still relatively unexplored. Herein, a highly enantioselective aza-Friedel-Crafts reaction of cyclic-ketimines and naphthols/phenols has been realized using a chiral phosphoric acid catalyst. A variety of chiral aminonaphthols (chiral indolin-3-ones) containing a quaternary stereocenter at the C2 position were obtained with excellent outcomes (up to 97% yield, 98% ee). Moreover, the synthetic utility of the enantiomerically enriched chiral aminonaphthols was demonstrated in some efficient transformations. According to the experimental results, a possible transition state model has been proposed to rationalize the origin of asymmetric induction.

Camellia oleifera is a high quality woody oilseed crop that produces a low yield in the central subtropics of China. Although fertilization can efficiently increase C. oleifera yield in these areas, the influences of fertilization continuously on soil microbiota and soil fertility remain poorly understood. The purpose of this study was to determine the influences of the type and amount of fertilizer on the soil properties of C. oleifera. Here, we compared the effects of organic fertilizer, organic–inorganic compost, no fertilizer control, and low (F1), medium (F2), and high (F3) amounts of continuously applied organic–inorganic compost at the sapling stage All chemical indicators and copiotropic bacteria measured were significantly lower in organic fertilizer and without fertilizer. Successive fertilization over two years with organic-inorganic compost significantly altered the relative abundance of the dominant bacterial groups at the phylum levels. the abundance of these phyla was the same in F2 and F3 treatments which was higher than their abundance in the other treatments. The relative abundance of kopiotrophic bacteria, especially proteobacteria and gemmatimonadetes, increased significantly and similarly with F2 and F3 treatments. With successive fertilizations, the levels of total nitrogen (TN), total phosphorus (TP) and organic matter (OM) were the vital factors affecting bacterial communities, which was confirmed by structural equation models, redundant analyzes and random forest models. These results suggest that the continuous application of moderate amounts of organic-inorganic compost is the main driver for the improvement of soil bacterial communities, and this was mainly achieved by altering the levels of OM, TN and TP, thus affecting the copiotropic bacterial abundance. This study provides a scientific basis for optimal fertilization of C. oleifera forest.

Herein, we report an efficient electrochemical activation of the C-C bond of aryl ketones for the preparation of amides under catalyst- and external-oxidant-free conditions using aliphatic amines as the N source. Under environmentally benign electrolysis conditions, a series of amides were synthesized in good yield. Our control experiments revealed that electricity plays an important role in this transformation.

A modified flux-coupling type superconducting fault current limiter (SFCL) is proposed here for suppressing fault currents. The modified SFCL consists of a coupling transformer, an yttrium barium copper oxide (YBCO) pancake coil, and a controlled switch. By flexibly adjusting the controlled switch's contact states based on the system operational conditions, the coupling transformer's primary inductance as well as the YBCO coil's normal-state resistance are incorporated into the main system for current limitation. Because the modified SFCL has the advantages of resistive and inductive SFCLs, it may improve the power system's transient behavior. Hence, the SFCL's effect on the transient stability of a multi-machine power system was also theoretically investigated. Further, simulations were conducted for accessing the SFCL's performance characteristics under different fault conditions. The results show that using the proposed SFCL can effectively restrain the increased fault current and improve the bus voltage sag; meanwhile, the imitated multi-machine system's power-angle oscillation can be obviously reduced.

In situ hydrogels with rapid hemostasis and antibacterial activity have received considerable attention in the field of wound healing. Herein, a white light and NIR dual light-responsive cellulose nanofibril (CNF)-based in situ hydrogel wound dressing is tailored by using white light-responsive CNF and endogenous antibacterial CNF as the skeleton, Prussian blue nanoparticles, Pluronic® F127 and hydroxypropyl methyl cellulose as the NIR, temperature-responsive switch and binder, respectively. The dressing exhibits rapid hemostasis properties in rat liver injury model with low blood loss of 286.4 mg and short hemostasis time of 63 s. Meanwhile, the antibacterial activity of the dressing with white and NIR irradiation against Escherichia coli, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) is higher than 99.9 %. Interestingly, the dressing with biocompatibility can promote MRSA infection wound healing and can be removed on demand without secondary injury to skin. Therefore, it has promising applications for first-aid hemostasis and wound healing.

An electrochemical dehydrogenative [2 + 2 + 1] annulation used for the synthesis of imidazoles has been developed under undivided electrolytic conditions. In an undivided cell, aryl ketones and amines can smoothly participate in this transformation to furnish a variety of substituted imidazoles. The reaction avoids the use of both transition-metal catalysts and peroxide reagents, which makes it more sustainable and renewable.

The recurrent outbreak of coronaviruses and variants underscores the need for broadly reactive antivirals and vaccines. Here, a novel broad-spectrum human antibody named 76E1 was isolated from a COVID-19 convalescent patient and showed broad neutralization activity against multiple α- and β-coronaviruses, including the SARS-CoV-2 variants and also exhibited the binding breath to peptides containing the epitope from γ- and δ- coronaviruses. 76E1 cross-protects mice from SARS-CoV-2 and HCoV-OC43 infection in both prophylactic and treatment models. The epitope including the fusion peptide and S2’ cleavage site recognized by 76E1 was significantly conserved among α-, β-, γ- and δ- coronaviruses. We uncovered a novel mechanism of antibody neutralization that the epitope of 76E1 was proportionally less exposed in the prefusion trimeric structure of spike protein but could be unmasked by binding to the receptor ACE2. Once the epitope exposed, 76E1 inhibited S2’ cleavage, thus blocked the membrane fusion process. Our data demonstrate a key epitope targeted by broadly-neutralizing antibodies and will guide next-generation epitope-based pan-coronavirus vaccine design.

Frequent outbreaks of coronaviruses underscore the need for antivirals and vaccines that can counter a broad range of coronavirus types. We isolated a human antibody named 76E1 from a COVID-19 convalescent patient, and report that it has broad-range neutralizing activity against multiple α- and β-coronaviruses, including the SARS-CoV-2 variants. 76E1 also binds its epitope in peptides from γ- and δ-coronaviruses. 76E1 cross-protects against SARS-CoV-2 and HCoV-OC43 infection in both prophylactic and therapeutic murine animal models. Structural and functional studies revealed that 76E1 targets a unique epitope within the spike protein that comprises the highly conserved S2' site and the fusion peptide. The epitope that 76E1 binds is partially buried in the structure of the SARS-CoV-2 spike trimer in the prefusion state, but is exposed when the spike protein binds to ACE2. This observation suggests that 76E1 binds to the epitope at an intermediate state of the spike trimer during the transition from the prefusion to the postfusion state, thereby blocking membrane fusion and viral entry. We hope that the identification of this crucial epitope, which can be recognized by 76E1, will guide epitope-based design of next-generation pan-coronavirus vaccines and antivirals.

Minerals are stored in the aleurone layer and embryo during maize seed development, but how they affect endosperm development and activity is unclear. Here, we cloned the gene underlying the classic maize kernel mutant shrunken4 (sh4) and found that it encodes the YELLOW STRIPE-LIKE oligopeptide metal transporter ZmYSL2. sh4 kernels had a shrunken phenotype with developmental defects in the aleurone layer and starchy endosperm cells. ZmYSL2 showed iron and zinc transporter activity in Xenopus laevis oocytes. Analysis using a specific antibody indicated that ZmYSL2 predominately accumulated in the aleurone and sub-aleurone layers in endosperm and the scutellum in embryos. Specific iron deposition was observed in the aleurone layer in wild-type kernels. In sh4, however, the outermost monolayer of endosperm cells failed to accumulate iron and lost aleurone cell characteristics, indicating that proper functioning of ZmYSL2 and iron accumulation are essential for aleurone cell development. Transcriptome analysis of sh4 endosperm revealed that loss of ZmYSL2 function affects the expression of genes involved in starch synthesis and degradation processes, which is consistent with the delayed development and premature degradation of starch grains in sh4 kernels. Therefore, ZmYSL2 is critical for aleurone cell development and starchy endosperm cell activity during maize seed development.

CO2/photoredox-cocatalyzed tandem oxidative cyclization of α-bromo ketones and amines for the preparation of substituted oxazoles has been achieved. The avoidance of using both transition-metal catalysts and peroxides makes this method more sustainable and renewable.

Cohesin complexes maintain sister chromatid cohesion to ensure proper chromosome segregation during mitosis and meiosis. In plants, the exact components and functions of the cohesin complex remain poorly understood. Here, we positionally cloned the classic maize (Zea mays) mutant defective kernel 15 (dek15), revealing that it encodes a homolog of SISTER CHROMATID COHESION PROTEIN 4 (SCC4), a loader subunit of the cohesin ring. Developing dek15 kernels contained fewer cells than the wild type, but had a highly variable cell size. The dek15 mutation was found to disrupt the mitotic cell cycle and endoreduplication, resulting in a reduced endosperm and embryo lethality. The cells in the dek15 endosperm and embryo exhibited precocious sister chromatid separation and other chromosome segregation errors, including misaligned chromosomes, lagging chromosomes, and micronuclei, resulting in a high percentage of aneuploid cells. The loss of Dek15/Scc4 function upregulated the expression of genes involved in cell cycle progression and stress responses, and downregulated key genes involved in organic synthesis during maize endosperm development. Our yeast two-hybrid screen identified the chromatin remodeling proteins chromatin remodeling factor 4, chromatin remodeling complex subunit B (CHB)102, CHB105, and CHB106 as SCC4-interacting proteins, suggesting a possible mechanism by which the cohesin ring is loaded onto chromatin in plant cells. This study revealed biological functions for DEK15/SCC4 in mitotic chromosome segregation and kernel development in maize.

This study evaluated whether resveratrol can alleviate intestinal injury and enhance the mitochondrial function and the mitophagy level in diquat induced oxidative stress of piglets. Twenty-four 35 day old piglets were randomly allocated to four groups: (1) nonchallenged control; (2) control + 100 mg kg-1 resveratrol diet; (3) diquat-treated control and (4) diquat + 100 mg kg-1 resveratrol diet. At the beginning of the experiment, the piglets were injected with diquat or saline (10 mg per kg bodyweight). On day 14, the piglets were killed to obtain the jejuna segments. The results showed that resveratrol increased (P < 0.05) the total antioxidant capacity (T-AOC) and decreased (P < 0.05) the hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels in the jejunal mucosa, in comparison with the diquat group. Resveratrol improved (P < 0.05) the intestinal barrier function, as indicated by the increased transepithelial electrical resistance and the decreased paracellular permeability of fluorescein isothiocyanate dextran 4 kDa in the jejunum. Moreover, resveratrol prevented (P < 0.05) the diquat induced decline of occludin, claudin-1 and ZO-1 levels in the jejunal mucosa. Resveratrol ameliorated mitochondria swelling, vacuolation and cracked cristae induced by diquat. Resveratrol decreased (P < 0.05) the ROS generation and increased (P < 0.05) the membrane potential of intestinal mitochondria, the content of mitochondrial DNA and the activity of mitochondrial complexes I-IV in the jejunum. Finally, resveratrol enhanced (P < 0.05) the level of PTEN induced putative kinase 1 (PINK1) and Parkin in intestinal mitochondria; meanwhile it increased (P < 0.05) the LC3-II/LC3-I ratio in the jejunum. These data indicate that resveratrol is effective in protecting the intestinal barrier, improving the redox status, alleviating mitochondrial damage and inducing mitophagy in piglets challenged with diquat.

A label free fluorescent peptide probe (HDSGWEVHH) was used for Cu2+ and S2− determination in aqueous solution. Our results demonstrated that HDSGWEVHH is highly selective and sensitive for monitoring free Cu2+ concentration via quenching of the probe fluorescence upon Cu2+ binding. The mechanism of the complexation is investigated with Cyclic Voltammetry (CV), 1H nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) spectroscopy and computational techniques. Theoretical calculation results indicated the binding ratio of the probe to Cu2+ is 2 : 1 and the binding constant was obtained as 1.72 × 10 8 M−1. Cu2+ concentration can be detected with the detection limit of 16 nM. Free Cu2+ concentration released from the metallothionein–Cu complex at different pH values was detected. Cu2+ concentration in real water and tea samples was also detected, and the results were consistent with the ones monitored by atomic absorption spectrometer. Because of the exceedingly small Ksp value of CuS (1.27 × 10−36), S2− can sequester Cu2+ from HDSGWEVHH to restore the tryptophan (W) fluorescence. Thus the HDSGWEVHH–Cu2+ complex can also be used for S2− detection. The S2− concentrations can be monitored with a detection limit of 19 nM. The assay is also amenable to measurement of S2− concentration in pure water samples. Thus the probe designed herein is sensitive, label free, low cost, and environmentally friendly for Cu2+ and S2− determination in aqueous solutions.

The design of injectable hydrogels with excellent biocompatibility, medical imaging, and antitumor activity to improve the therapeutic efficiency on tumor tissues and to reduce toxic side effects is very important in clinical practice. A novel medically imageable pH-, temperature- and NIR- intelligent cellulose nanofibril (TOCNF)-based injectable hydrogel was designed using pH-, and temperature-responsive TOCNF as the carrier, citric-acid-stabilized Prussian blue nanoparticles (PBNPs) as the contrast agent and photothermal switch, and doxorubicin (DOX) as the chemotherapeutics agent. The hydrogel possessed a nanocage structure and a 3D network structure, which allowed a high loading capacity of PBNPs (2 mg/g) and DOX (415 mg/g). The PBNPs stabilized on TOCNF through electrostatic interactions and hydrogen bond could aid medical magnetic resonance imaging (MRI) and photoacoustic imaging (PAI). Interestingly, the temperature, pH, and NIR tri-stimuli-responsive intelligent switches, inspired by the mimosa leaf, contributed to the controllable sustained DOX release property of the hydrogel. Therefore, in vivo bimodal MRI/PAI and tumor therapy results showed that the previously prepared hydrogel could be ideal for the rapid diagnosis and chemo-photothermal therapy in the clinical treatment of tumors.

Long-term cultivation of woody species would change soil microbial community and metabolites composition, and then affect soil ecological function. Camellia oleifera is an important economically cultivar grown in subtropical regions of China but its effect on soil quality and health remains unclear. Soil bacterial communities and metabolome composition are investigated in this study via high-throughput sequencing and soil metabolomics to determine soil quality under different growth stages (sapling, maturity, and degeneration periods) of C. oleifera. Main results revealed that soil metabolite composition reaches equilibrium faster than microorganisms. Higher carbohydrate content (such as trehalose, mannopyranose, and sucrose) during degeneration stages of C. oleifera induces the decrease of Chloroflexi and Actinobacteria abundances and results in lower disease resistance potential than that of sapling and mature stages. Long-term cultivation of C. oleifera soil showed significantly higher abundance of carbon, nitrogen, and phosphorus metabolism, and presented significantly higher soil organic matter, available nitrogen, and available phosphorus contents. Results demonstrated that long-term C. oleifera cultivation can significantly improve soil fertility but potentially cause the decline of soil ecological health.

The inhibitory effects of Portulaca oleracea L. (PO) and its flavonoid ingredients on the formation of heterocyclic amines (HAs) in roast beef patties were investigated. Ten HAs were found in control patties, and the total content was 212.73 ± 7.13 ng/g. With the addition of PO (1%, 5%, and 10%, w/w), HAs decreased by 62.39%, 68.03%, and 73.75%, respectively. The main flavonoid ingredients (rutin, hesperidin, and flavanone) also present a similar inhibitory effect. The Density Function Theory (DFT) methods were adopted to investigate the inhibitory mechanism. These ingredients bonded with the intermediate to block the formation of norharman. Both experimental and calculated data of the ingredients were analyzed on their HAs inhibitory capacity. Our results provide a novel and valuable strategy to reduce HAs via a low additive level of medicinal and edible plants. And the correlation between experimental and calculated data could be applied to predict the inhibitory ability of inhibitors.

In order to study the effect of tooth surface wear on gear dynamics, based on the Archard wear model, considering the dynamic load distribution between teeth under the geometrical normal clearance and influence of the contact point on the tooth profile points in the surrounding area, an accurate wear model of tooth surface is established and the dynamic characteristics of gear are analyzed by coupling the wear of gear surface into the gear dynamics model, and a dynamic wear calculation model of gear surface is established. The results indicate that early wear has little effect on gear dynamics, with the increase of wear cycle, the vibration of the non-resonant region is increased, while in the resonance region first invariant and then increased.

Synthesis of aziridines by electrochemical oxidative annulation of chalcone 1,3-diphenyl-2-propen-1-one with primary amines has been developed under external oxidant - and base-free conditions. The reaction constitutes a new transformation of chalcones with primary amines to aziridines, providing a complementary, simple, and environmentally friendly approach to the currently available methods. A reaction mechanism for this transformation has been proposed based on the cyclic voltammetry.

Potassium maintains cotton fiber cell elongation under conditions of calcium deficiency, through the CBL-INTERACTING PROTEIN KINASE 6 (GhCIPK6) gene., Calcium (Ca2+) is necessary for fiber cell development in cotton (Gossypium hirsutum), both as a cell wall structural component and for environmental signaling responses. It is also known that potassium (K+) plays a critical role in cotton fiber cell elongation. However, it is unclear whether Ca2+ integrates its activities with K+ to regulate fiber elongation. Here, we report the novel discovery that Ca2+ deficiency, when integrated with K+ signaling, promotes fiber elongation. Using inductively coupled plasma–mass spectrometry (ICP-MS), we determined dynamic profiles of the ionome in ovules and fibers at different developmental stages, and found that a high accumulation of macro-elements, but not Ca2+, was associated with longer fibers. Using an in vitro ovule culture system, we found that under Ca2+-deficient conditions, sufficient K+ (52 mM) rapidly induced ovule and fiber browning, while reduced K+ (2 or 27 mM) not only suppressed tissue browning but also altered fiber elongation. Reduced K+ also enhanced reactive oxygen species scavenging ability and maintained abscisic acid and jasmonic acid levels, which in turn compensated for Ca2+ deficiency. Ca2+ deficiency combined with reduced K+ (0 mM Ca2+ and 27 mM K+) produced longer fibers in cultured ovules, due to cell wall loosening by phytosulfokine (PSK), expansin (EXP), and xyloglucan endotransglycosylase/hydrolase (XTH), and an increase of the K+ content of fiber cells. Using transgenic cotton, we showed that the CBL-INTERACTING PROTEIN KINASE 6 (GhCIPK6) gene mediates the uptake of K+ under Ca2+-deficient conditions. This study establishes a new link between Ca2+, K+, and fiber elongation.

An electrochemical multicomponent [3 + 1 + 1] annulation used for the synthesis of 1,3,5-trisubstituted 1,2,4-triazoles has been developed under transition-metal-, acid-, base- and external-oxidant-free conditions. In an undivided cell, a variety of hydrazones and aldehydes smoothly participate in this transformation to furnish a range of substituted 1,2,4-triazoles. The reaction constitutes a new transformation from hydrazones, aldehydes and NH4OAc into 1,2,4-triazoles, providing a unifying, simple and environmentally friendly approach to the currently available methods.

The direct alkylheteroarylation of alkenes with cyclic and acyclic ethers via distal heteroaryl ipso-migration has been accomplished through the design of a photoredox-mediated C-H functionalization pathway. The use of inexpensive ethers as radical precursors combined with a straightforward method makes this a practical approach.

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