Transcription factor PbNAC71 regulates xylem and vessel development to control plant height.

Dwarfism is an important agronomic trait in fruit breeding programs. However, the germplasm resources required to generate dwarf pear (Pyrus spp.) varieties are limited. Moreover, the mechanisms underlying dwarfism remain unclear. In this study, "Yunnan" quince (Cydonia oblonga Mill.) had a dwarfing effect on "Zaosu" pear. Additionally, the dwarfism-related NAC transcription factor gene PbNAC71 was isolated from pear trees comprising "Zaosu" (scion) grafted onto "Yunnan" quince (rootstock). Transgenic Nicotiana benthamiana and pear OHF-333 (Pyrus communis) plants overexpressing PbNAC71 exhibited dwarfism, with a substantially smaller xylem and vessel area relative to the wild-type controls. Yeast one-hybrid, dual-luciferase, chromatin immunoprecipitation-qPCR, and electrophoretic mobility shift assays indicated that PbNAC71 downregulates PbWalls are thin 1 expression by binding to NAC-binding elements in its promoter. Yeast two-hybrid assays showed that PbNAC71 interacts with the E3 ubiquitin ligase PbRING finger protein 217 (PbRNF217). Furthermore, PbRNF217 promotes the ubiquitin-mediated degradation of PbNAC71 by the 26S proteasome, thereby regulating plant height as well as xylem and vessel development. Our findings reveal a mechanism underlying pear dwarfism and expand our understanding of the molecular basis of dwarfism in woody plants.

Coexistence of Ferroelectricity and Ferromagnetism in Atomically Thin Two-Dimensional Cr2S3/WS2 Vertical Heterostructures.

Two-dimensional (2D) heterostructures with ferromagnetism and ferroelectricity provide a promising avenue to miniaturize the device size, increase computational power, and reduce energy consumption. However, the direct synthesis of such eye-catching heterostructures has yet to be realized up to now. Here, we design a two-step chemical vapor deposition strategy to growth of Cr2S3/WS2 vertical heterostructures with atomically sharp and clean interfaces on sapphire. The interlayer charge transfer and periodic moiré superlattice result in the emergence of room-temperature ferroelectricity in atomically thin Cr2S3/WS2 vertical heterostructures. In parallel, long-range ferromagnetic order is discovered in 2D Cr2S3 via the magneto-optical Kerr effect technique with the Curie temperature approaching 170 K. The charge distribution variation induced by the moiré superlattice changes the ferromagnetic coupling strength and enhances the Curie temperature. The coexistence of ferroelectricity and ferromagnetism in 2D Cr2S3/WS2 vertical heterostructures provides a cornerstone for the further design of logic-in-memory devices to build new computing architectures.

Early cartilage lesion and 5-year incident joint surgery in knee osteoarthritis patients: a retrospective cohort study.

OBJECTIVE: to investigate the association between cartilage lesion-related features observed in knee osteoarthritis (OA) patients' first MRI examination and incident knee surgery within 5 years. Additionally, to assess the predictive value of these features for the incident knee surgery. METHODS: We identified patients diagnosed with knee OA and treated at our institution between January 2015 and January 2018, and retrieved their baseline clinical data and first MRI examination films from the information system. Next, we proceeded to determine joint space narrowing grade, cartilage lesion size grade, cartilage full-thickness loss grade and cartilage lesion sum score for the medial and lateral compartments, respectively. Generalized linear regression models examined the association of these features with 5-year incident knee surgery. Positive and negative predictive values (PPVs and NPVs) were determined referring to 5-year incident knee surgery. RESULTS: Totally, 878 participants (knees) were found eligible to form the study population. Within the 5 years, surgery was performed on 61 knees. None of the cartilage-related features had been found significantly associated with incident surgery. The results were similar for medial and lateral compartments. The PPVs were low for all the features. CONCLUSIONS: Among symptomatic clinically diagnosed OA knees, cartilage lesions observed in the first MRI examinations were not found to be associated with the occurrence of joint surgery within a 5-year period. All these cartilage-related features appear to have no additional value in predicting 5-year incident joint surgery.

Interisland-Distance-Mediated Growth of Centimeter-Scale Two-Dimensional Magnetic Fe3O4 Arrays with Unidirectional Domain Orientations.

Two-dimensional (2D) nanosheet arrays with unidirectional orientations are of great significance for synthesizing wafer-scale single crystals. Although great efforts have been devoted, the growth of atomically thin magnetic nanosheet arrays and single crystals is still unaddressed. Here we design an interisland-distance-mediated chemical vapor deposition strategy to synthesize centimeter-scale atomically thin Fe3O4 arrays with unidirectional orientations on mica. The unidirectional alignment of nearly all the Fe3O4 nanosheets is driven by a dual-coupling-guided growth mechanism. The Fe3O4/mica interlayer interaction induces two preferred antiparallel orientations, whereas the interisland interaction of Fe3O4 breaks the energy degeneracy of antiparallel orientations. The room-temperature long-range ferrimagnetic order and thickness-tunable magnetic domain evolution are uncovered in atomically thin Fe3O4. This strategy to tune the orientations of nanosheets through the an interisland interaction can guide the synthesis of other 2D transition-metal oxides, thereby laying a solid foundation for future spintronic device applications at the integration level.

FeN Coordination Induced Ultralong Lifetime of Sodium-Ion Battery with the Cycle Number Exceeding 65 000.

Sodium-ion batteries (SIBs) have received increasing attention because of their appealing cell voltages and cost-effective features. However, the atom aggregation and electrode volume variation inevitably deteriorate the sodium storage kinetics. Here a new strategy is proposed to boost the lifetime of SIB by synthesizing sea urchin-like FeSe2 /nitrogen-doped carbon (FeSe2 /NC) composites. The robust FeN coordination hinders the Fe atom aggregation and accommodates the volume expansion, while the unique biomorphic morphology and high conductivity of FeSe2 /NC enhance the intercalation/deintercalation kinetics and shorten the ion/electron diffusion length. As expected, FeSe2 /NC electrodes deliver excellent half (387.6 mAh g-1 at 20.0 A g-1 after 56 000 cycles) and full (203.5 mAh g-1 at 1.0 A g-1 after 1200 cycles) cell performances. Impressively, an ultralong lifetime of SIB composed of FeSe2 /Fe3 Se4 /NC anode is uncovered with the cycle number exceeding 65 000. The sodium storage mechanism is clarified with the aid of density function theory calculations and in situ characterizations. This work hereby provides a new paradigm for enhancing the lifetime of SIB by constructing a unique coordination environment between active material and framework.

The ubiquitin-binding protein MdRAD23D1 mediates drought response by regulating degradation of the proline-rich protein MdPRP6 in apple (Malus domestica).

RAD23 (RADIATION SENSITIVE23) proteins are a group of UBL-UBA (ubiquitin-like-ubiquitin-associated) proteins that shuttle ubiquitylated proteins to the 26S proteasome for breakdown. Drought stress is a major environmental constraint that limits plant growth and production, but whether RAD23 proteins are involved in this process is unclear. Here, we demonstrated that a shuttle protein, MdRAD23D1, mediated drought response in apple plants (Malus domestica). MdRAD23D1 levels increased under drought stress, and its suppression resulted in decreased stress tolerance in apple plants. Through in vitro and in vivo assays, we demonstrated that MdRAD23D1 interacted with a proline-rich protein MdPRP6, resulting in the degradation of MdPRP6 by the 26S proteasome. And MdRAD23D1 accelerated the degradation of MdPRP6 under drought stress. Suppression of MdPRP6 resulted in enhanced drought tolerance in apple plants, mainly because the free proline accumulation is changed. And the free proline is also involved in MdRAD23D1-mediated drought response. Taken together, these findings demonstrated that MdRAD23D1 and MdPRP6 oppositely regulated drought response. MdRAD23D1 levels increased under drought, accelerating the degradation of MdPRP6. MdPRP6 negatively regulated drought response, probably by regulating proline accumulation. Thus, "MdRAD23D1-MdPRP6" conferred drought stress tolerance in apple plants.

The apple BTB protein MdBT2 positively regulates MdCOP1 abundance to repress anthocyanin biosynthesis.

The ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) plays a central role in light-induced anthocyanin biosynthesis. However, the upstream regulatory factors of COP1 remain poorly understood, particularly in horticultural plants. Here, we identified an MdCOP1-interacting protein, BROAD-COMPLEX, TRAMTRACK AND BRIC A BRAC2 (MdBT2), in apple (Malus domestica). MdBT2 is a BTB protein that directly interacts with and stabilizes MdCOP1 by inhibiting self-ubiquitination. Fluorescence observation and cell fractionation assays showed that MdBT2 increased the abundance of MdCOP1 in the nucleus. Moreover, a series of phenotypic analyses indicated that MdBT2 promoted MdCOP1-mediated ubiquitination and degradation of the MdMYB1 transcription factor, inhibiting the expression of anthocyanin biosynthesis genes and anthocyanin accumulation. Overall, our findings reveal a molecular mechanism by which MdBT2 positively regulates MdCOP1, providing insight into MdCOP1-mediated anthocyanin biosynthesis.

Exercise-induced increases of corticosterone contribute to exercise-enhanced adult hippocampal neurogenesis in mice.

Adult hippocampal neurogenesis (AHN) is suppressed by chronic stress. The negative effect of stress is mainly attributed to increased levels of stress hormones (e.g. glucocorticoids, GCs). Exercise enhances AHN, yet it also stimulates GC secretion. To delineate the paradoxical role of GCs, we took the advantage of a unique mouse strain (L/L) which exhibits an inert response to stress-induced secretion of GCs to study the role of GCs in exercise-induced AHN. Our results showed that basal corticosterone (CORT), the main GCs in rodents, levels were similar between the L/L mice and wild-type (WT) mice. However, levels of CORT in the L/L mice were barely altered and significantly lower than those of the WT mice during treadmill running (TR). AHN was enhanced by 4 weeks of TR in the WT mice, but not L/L mice. WT mice that received daily injection of CORT to evoke serum CORT levels similar to those during exercise for 4 weeks did not affect AHN, whereas injection with large amount of CORT inhibited AHN. Taken together, our results indicated that exercise-related elevation of CORT participates in exercise-enhanced AHN. CORT alone is not sufficient to elicit AHN and may inhibit AHN if the levels are high.

Effects of combined administration of calcium, iron, zinc, chrysanthemum flavonoids, and DMSA on the treatment of lead intoxication in mice.

The effect of combined administration of calcium (Ca), iron (Fe), zinc (Zn), chrysanthemum flavonoids, and meso-2,3-dimercaptosuccinic acid (DMSA) on the treatment of lead (Pb) intoxication in mice was studied. One hundred ninety female mice (SPF level, aged 18-22 days) were randomly divided into two groups as experimental animals. Mice in group I (10 mice) served as normal control animals, and were administered deionized water containing 12.5 µL/L acetate acid for 6 weeks, whereas mice in group II (180 mice) were exposed to 0.1% (wt/vol) of lead acetate in deionized water for 6 weeks and served as experimental animals. After 6 weeks of successful modeling, 180 mice from group II (lead-exposed) were divided into 18 groups of 10 mice each, 16 of which were treated by the combined administration of Ca, Fe, Zn, chrysanthemum flavonoids, and DMSA by L16 (215 ) orthogonal design. The remaining two groups were given treatment with low and high doses of DMSA, respectively. After three weeks of intervention (ig), the optimal treatment group was identified according to its blood lead level, as well as some antioxidant indices in the blood, liver, and hippocampus. The results indicated that the combined administration of Fe, Zn, chrysanthemum flavonoids, and DMSA with low dosage had the most significant effect on increasing the activities of blood delta-aminolevulinic acid dehydratase and superoxide dismutase (SOD), hepatic SOD and hippocampus nitric oxide synthase while decreasing the blood lead level, the content of hepatic malondialdehyde and hippocampus nitric oxide; this was considered the optimal treatment group. There was no difference in the level of blood hemoglobin between the optimal treatment group and the model control group (the first group of the orthogonal experiment). The activities of blood glutathione (GSH), hepatic GSH and glutathione peroxidase of the optimal treatment group were the same as other groups', and the recovery of the related indexes in the optimal effect group closely resembled the high dosage DMSA group. It can be concluded that the coadministration of Fe, Zn, and chrysanthemum flavonoids along with a low-dose DMSA effectively reduces Pb poisoning and lead-induced oxidative damage in lead-exposed mice; the result may provide a theoretical reference for the treatment of Pb poisoning.

Redox-Neutral Nickel(II) Catalysis: Hydroarylation of Unactivated Alkenes with Arylboronic Acids.

Reported here is the discovery of a redox-neutral NiII /NiII catalytic cycle which is capable of the linear-selective hydroarylation of unactivated alkenes with arylboronic acids for the first time. This novel catalytic cycle, enabled by the use of an electron-rich diimine ligand, features broad substrate scope, and excellent functional-group and heterocycle compatibility under mild reaction conditions in the absence of additional oxidants and reductants. Mechanistic investigations using kinetic analysis and deuterium-labelling experiments revealed the protonation to be the rate-determining step in this redox-neutral catalysis, and the reversible chain-walking nature of the newly developed diimine-Ni catalyst.

Effects of LPS on the accumulation of lipid droplets, proliferation, and steroidogenesis in goat luteinized granulosa cells.

Lipopolysaccharide (LPS) can cause ovarian dysfunction and infertility in mammals. The purpose of this study was to investigate the effects of LPS on the accumulation of lipid droplets (LDs), proliferation, and steroidogenesis in goat luteinized granulosa cells (LGCs). GCs isolated from the ovarian follicles were spontaneously luteinized under media with fetal bovine serum, resulting in increased progesterone and shifted shape from spherical to star with multiple prolongations. Then, LGCs were treated with LPS (0-10 µg/mL) for 0-48 hours. Oil Red O staining was performed to observe LDs accumulation and commercial kit was applied to detect intracellular triglyceride (TG) content. The cell proliferation were detected by cell counting kit-8. Expressions of cell-cycle-related genes were determined by real-time polymerase chain reaction. Estradiol (E 2 ) and progesterone (P 4 ) from cell supernatants were determined by enzyme-linked immunosorbent assay, and expressions of STAR, P450scc, 3ß-hydroxysteroid dehydrogenase (3ß-HSD) and CYP19A1 were detected by Western blot. Results showed that LPS treatment significantly increased LDs accumulation after 24 hours, and 5 µg/mL LPS increased TG content ( P < 0.05). LPS treatment for 24 hours stimulated the LGCs activities ( P<0.05), which was confirmed by the increases in the expressions of proliferating cell nuclear antigen (PCNA), cyclinB1 and cyclinD1, while 48 hours treatment had no effect. LPS treatment suppressed E 2 and P 4 output of LGCs ( P < 0.05). Western blot results showed that 10 µg/mL LPS decreased the protein expression of 3ß-HSD in LGCs ( P < 0.05). In conclusion, LPS increased LDs accumulation and cell proliferation, and LPS-mediated P 4 reduction could be attributed to the decreased 3ß-HSD protein expression, which provide new information for the regulation of ovarian function in goats.

[Study on commodity specification and grade standard and quality evaluation of Dipsaci Radix].

Through the records of herbal and market investigations,the samples collected from different market and origin were analyzed,and the appearance character indexes were determined in order to revise the commodity specification and grade standard of Dipsaci Radix combined with production practice. This is also to analyze association of the appearance with quality different of intrinsic components. The investigation results indicated the root's long and thick was better,and atrovirens of fracture surface,there are most of the market is dominated by the ungraded goods. Through principal component analysis,variance analysis and cluster analysis,combining with the feasibility of actual operation and herbal record,the length,middle diameter and phloem color were filtrated and the specification was divided into 2 ranks: the selection and ungraded goods,and the grade was divided into 2 ranks for the selection goods: big,small selected goods. Moreover,there were no significant correlation between the appearance and the intrinsic quality index of Dipsaci Radix,the content of extractum were significantly positive correlation with the moisture,but had extremely negative correlation with the total ash. Multiple comparisons indicated that the content of the moisture,extractum and asperosaponin VI of the selected goods were higher than the ungraded goods,while the total ash content were lower,and they hasn't significant difference. The commodity specification and grade standard of Dipsaci Radix as a basis provide commodity specification and grade standard of communities and standardizing market trade order.

[Study on commodity specification and grade standard and quality evaluation of Galla Chinensis].

This paper is aimed to study the commodity specification and grade standard of Galla Chinensis,for standardizing market order and guide the market circulation,and provide a basis for standardization of Galla Chinensis. With 33 samples of Galla Chinensis from market as the object of the research,the herbal textual research and market research were carried out. Then the grading indicator were selected by the descriptive statistics,principal component analysis and cluster analysis,combining with production practice,the commodity specification and grade standard of Galla Chinensis were set out. The data of moisture,ash,gallic acid as the internal index were used to analyze the relationship between the quality difference between grades and the appearance characters and the intrinsic composition. Herbal textual research and market research found that the high quality of Galla Chinensis characterized with large,complete,wall thick,grayish brown characteristics,and Galla Chinensis could be divided into gallnuts and horned gall. Through principal component analysis and cluster analysis,combining actual production and herbal record,screening,the length,diameter,single weight,the number of 500 g were determined as 4 grading indicators,the commodity specification was divided into two: gallnuts and horned gall,the grades was divided into two: selected goods and mixed goods. The result of correlation analysis showed there was no significant correlation between the internal index and the appearance characters of Galla Chinensis. The result of multiple comparison showed that the ash content of the selected goods was smaller than that of the mixed goods,but it did not reach significant. The content of gallic acid of the selected goods and the mixed goods of gallnuts were higher than selected goods of horned gall,and higher than mixed goods of horned galls. Using the length,diameter,single weight,the number of 500 g as the appearance characters index. Combining with the herbal textual research and market research,we have divided two specifications and two grades for the commodity specification and grade standard of Galla Chinensis,which can provide a basis for industry standards and national standards.

Anti-TGFß-1 receptor inhibitor mediates the efficacy of the human umbilical cord mesenchymal stem cells against liver fibrosis through TGFß-1/Smad pathway.

The aim of the current investigation was to evaluate the anti-fibrosis potential of human umbilical cord mesenchymal stem cells (hUC-MSCs) and further to explore some of its underlying mechanisms. Hepatic fibrosis mice model was induced by CCl4. Liver function parameters in serum and fibrosis-associated markers in tissues were detected. Moreover, SB-431542, an anti-TGFß-1 receptor inhibitor, was employed in vitro to reveal the underlying mechanism of TGFß-1/Smad pathway on hUC-MSCs against liver fibrosis. In the present study, we illustrated that hUC-MSCs could differentiate into osteogenic, adipogenic, and cartilage. Liver fibrosis was attenuated with hUC-MSCs treatment, determined by reductions of AST, ALT. and fibrosis area, along with some critical parameters including TGFß-1, α-SMA, and TIMP-1. However, TGFß-1 receptor antagonist SB-431542 reduced the paracrine TGFß-1 expression of hUC-MSCs and blunted the activation of downstream target genes. Furthermore, the restrained hUC-MSCs proliferation and migration induced by SB-431542 could be reversed by si-TGFß-1. These results demonstrated that TGFß-1 receptor inhibitor improved the repair potential of hUC-MSCs against hepatic injury through TGFß-1/Smad pathway, which contributed to improving the therapeutic efficiency of liver fibrosis.

The End of China's One-Child Policy.

Starting on January 1, 2016, all Chinese couples are allowed to have two children. This marks the end of China's one-child policy, which has restricted the majority of Chinese families to only one child for the last 35 years. Yet, China's policy change came at least a decade later than it should have. The costly lessons to be learned are not only in politics and public policymaking, but also in how parts of the academic community informed and misinformed public policymaking.

Vertical Transmission of PCV2b to Fetuses in Sows Intramuscularly Infected with PCV2b.

In order to investigate whether PCV2b can be transmitted across the placenta in sows thereby causing vertical infection of fetuses, six sows in 75 day of pregnancy were either intramuscularly inoculated with a PCV2b culture supernatant (n = 4) or mock infected with cell culture supernatant (n = 2). At parturition, 3 newborn piglets from each litter were randomly selected and euthanatized prior to suckling. Samples of the mesenteric lymph nodes, spleens, kidneys, hearts and lungs were collected for PCR, histopathological and immunohistochemical assays. The results showed that the newborn piglets from PCV2b-infected sows had histopathological lesions in the tested tissues. Moreover, PCV2b antigen and DNA were detected as well. These findings therefore suggested that porcine circovirus type 2b can be transmitted across the placenta of sows, thereby leading to PCV2b vertical infection of the fetuses.

A bat biomimetic model for scenario recognition using echo Doppler information.

The flying bat can detect the difference in Doppler frequency between its echolocation transmission signal and the echoes in its surroundings, enabling it to distinguish between various scenarios effectively. By examining the bio-sonar biomimetic model of a flying bat that uses echo Doppler information for environmental recognition, it may enhance the scene recognition capability of human ultrasound sonar during movement. The paper establishes a three-dimensional clutter model of the flying state of bat bio-sonar for bats emitting constant frequency signals. It proposes a scene recognition method that combines multi-scale time-frequency feature analysis with a convolutional neural network (CNN). The short-time Fourier transform of different scales extract the Doppler and range dimensions, which are then fused to create a multi-scale feature plane containing both Doppler and range information. Combined with CNN's powerful image classification and recognition capabilities, extract features from multi-scale feature planes of different clutter scenes to achieve environment recognition based on the differences in Doppler and range dimensions of echoes in various directions. Through computer simulations, this study provides a numerical interpretation of the environmental classification and perception capabilities of bats in flight. The algorithm significantly improves scenario classification and recognition performance according to simulation results, with accuracy exceeding 98% in varied clutter scenarios at 30 dB signal noise ratio. Based on computer simulations, an experimental scene was constructed and actual echo signals were collected and analyzed. The experiments demonstrate that utilizing Doppler information enables the classification and recognition of cluttered environments. The effectiveness of the proposed algorithm was also verified. Ultrasonic sonar systems, such as navigation robots and helicopter obstacle avoidance, can apply this biomimetic model and algorithm for environmental recognition during motion.

Myricetin, a natural inhibitor of CD147, increases sensitivity of cisplatin in ovarian cancer.

BACKGROUND: Ovarian cancer (OC) is the most lethal gynecological tumor, but it currently lacks effective therapeutic targets. CD147, which is overexpressed in OC, plays a crucial role in promoting malignant progression and is associated with poor prognosis in patients. Therefore, CD147 has been identified as a potential therapeutic target. However, there is a limited amount of research on the development of CD147 inhibitors. METHODS: Surface plasmon resonance (SPR) assay and virtual molecular docking analysis were performed to identify potential natural compounds targeting CD147. The anti­tumor effects of myricetin were evaluated using various assays, including CCK8, Alkaline comet, immunofluorescence and xenograft mouse models. The underlying mechanism was investigated through western blot analysis and lentivirus short hairpin RNA (LV-shRNA) transfection. RESULTS: Myricetin, a flavonoid commonly found in plants, was discovered to be a potent inhibitor of CD147. Our findings demonstrated that myricetin exhibited a strong affinity for CD147 and down-regulated the protein level of CD147 by facilitating its proteasome-dependent degradation. Additionally, we observed synergistic antitumor effects of myricetin and cisplatin both in vivo and in vitro. Mechanistically, myricetin suppressed the expression of FOXM1 and its downstream DNA damage response (DDR) genes E×O1and BRIP1, thereby enhancing the DDR induced by cisplatin. CONCLUSION: Our data demonstrate that myricetin, a natural inhibitor of CD147, may have clinical utility in the treatment of OC due to its ability to increase genomic toxicity when combined with cisplatin.

Multiple stresses induced by chronic exposure to flupyradifurone affect honey bee physiological states.

Flupyradifurone (FPF) has been reported to have a potential risk to terrestrial and aquatic ecosystems. In the present study, the effects of chronic FPF exposure on bees were systematically investigated at the individual behavioral, tissue, cell, enzyme activity, and the gene expression levels. Chronic exposure (14 d) to FPF led to reduced survival (12 mg/L), body weight gain (4 and 12 mg/L), and food utilization efficiency (4 and 12 mg/L). Additionally, FPF exposure (12 mg/L) impaired sucrose sensitivity and memory of bees. Morphological analysis revealed significant cellular and subcellular changes in brain neurons and midgut epithelial cells, including mitochondrial damage, nuclear disintegration, and apoptosis. FPF exposure (4 and 12 mg/L) led to oxidative stress, as evidenced by increased lipid peroxidation and alterations in antioxidant enzyme activity. Notably, gene expression analysis indicated significant dysregulation of apoptosis, immune, detoxification, sucrose responsiveness and memory-related genes, suggesting the involvement of different pathways in FPF-induced toxicity. The multiple stresses and potential mechanisms described here provide a basis for determining the intrinsic toxicity of FPF.

Is the expression of different discrete emotions related to time? Evidence from online Chinese reviews using sentiment analysis and human behavior dynamics.

Objectives: The online behavior of online users has taken on complex and diverse characteristics, and posting product reviews on e-commerce platforms is no exception. In fact, reviews contain rich and multi-dimensional discrete emotional information, and whether there is a relationship between the expression of these different discrete emotions and the time interval between product purchase and review posting as well as their related characteristics are the issues that this study needs to analyze and solve in depth. Methods: Based on the OCC model (named after three proposers) of psychological emotional cognitive evaluation theory as the basis for emotion classification, the study used the massive amounts of Chinese reviews of mobile phones on the Chinese e-commerce platform Jingdong Mall as the research object, applied supervised machine learning methods to classify discrete emotions, and constructed a large corpus containing satisfaction, disappointment, admiration, reproach, love, and hate; then the study delved into the distribution and behavioral dynamics characteristics of consumers' comments containing the different discrete emotions at different "purchase-comment" time intervals. Results: The results showed that the first peak of the distribution curves of the six discrete emotions at different "purchase-comment" time intervals occurs on the first day after purchase and then decreases gradually but at different rates. The three curves for satisfaction, love, and hate emotions also show a second peak on the eleventh day, which is more similar to the bimodal distribution, implying that the corresponding product reviews are more objective. In addition, the distribution of reviews containing the six discrete emotions at different "purchase-comment" time intervals follows a power-law distribution and has the temporal characteristics of human behavioral dynamics, that is, "strong paroxysms and weak memory". However, the reviews containing the admiration and reproach emotions were most intensively written by consumers after the purchase, indicating that the service provided by the seller, logistics, and e-commerce platform stimulates more consumers to give quick responses and detailed reviews. Conclusion: This study is not only of great significance for exploring the internal mechanisms of consumer discrete emotional expression but also provides important decision-making references for potential consumer purchasing decisions, product updates for developers, marketing strategy formulation for marketing teams, and service improvement for sellers, logistics companies, and e-commerce platforms.