Spatiotemporal beating and vortices of van der Waals hyperbolic polaritons.

In conventional thin materials, the diffraction limit of light constrains the number of waveguide modes that can exist at a given frequency. However, layered van der Waals (vdW) materials, such as hexagonal boron nitride (hBN), can surpass this limitation due to their dielectric anisotropy, exhibiting positive permittivity along one optic axis and negativity along the other. This enables the propagation of hyperbolic rays within the material bulk and an unlimited number of subdiffractional modes characterized by hyperbolic dispersion. By employing time-domain near-field interferometry to analyze ultrafast hyperbolic ray pulses in thin hBN, we showed that their zigzag reflection trajectories bound within the hBN layer create an illusion of backward-moving and leaping behavior of pulse fringes. These rays result from the coherent beating of hyperbolic waveguide modes but could be mistakenly interpreted as negative group velocities and backward energy flow. Moreover, the zigzag reflections produce nanoscale (60 nm) and ultrafast (40 fs) spatiotemporal optical vortices along the trajectory, presenting opportunities to chiral spatiotemporal control of light-matter interactions. Supported by experimental evidence, our simulations highlight the potential of hyperbolic ray reflections for molecular vibrational absorption nanospectroscopy. The results pave the way for miniaturized, on-chip optical spectrometers, and ultrafast optical manipulation.

Bio-inspired Double Angstrom-Scale Confinement in Ti-deficient Ti0.87 O2 Nanosheet Membranes for Ultrahigh-performance Osmotic Power Generation.

Osmotic power, a clean energy source, can be harvested from the salinity difference between seawater and river water. However, the output power densities are hampered by the trade-off between ion selectivity and ion permeability. Here we propose an effective strategy of double angstrom-scale confinement (DAC) to design ion-permselective channels with enhanced ion selectivity and permeability simultaneously. The fabricated DAC-Ti0.87 O2 membranes possess both Ti atomic vacancies and an interlayer free spacing of ≈2.2 Å, which not only generates a profitable confinement effect for Na+ ions to enable high ion selectivity but also induces a strong interaction with Na+ ions to benefit high ion permeability. Consequently, when applied to osmotic power generation, the DAC-Ti0.87 O2 membranes achieved an ultrahigh power density of 17.8 W m-2 by mixing 0.5/0.01 M NaCl solution and up to 114.2 W m-2 with a 500-fold salinity gradient, far exceeding all the reported macroscopic-scale membranes. This work highlights the potential of the construction of DAC ion-permselective channels for two-dimensional materials in high-performance nanofluidic energy systems.

Emission Trade-Off between Isoprene and Other BVOC Components in Pinus massoniana Saplings May Be Regulated by Content of Chlorophylls, Starch and NSCs under Drought Stress.

The aim of this work was to study the changes in the BVOCs emission rates and physiological mechanistic response of Pinus massoniana saplings in response to drought stress. Drought stress significantly reduced the emission rates of total BVOCs, monoterpenes, and sesquiterpenes, but had no significant effect on the emission rate of isoprene, which slightly increased under drought stress. A significant negative relationship was observed between the emission rates of total BVOCs, monoterpenes, and sesquiterpenes and the content of chlorophylls, starch, and NSCs, and a positive relationship was observed between the isoprene emission rate and the content of chlorophylls, starch, and NSCs, indicating different control mechanism over the emission of the different components of BVOCs. Under drought stress, the emission trade-off between isoprene and other BVOCs components may be driven by the content of chlorophylls, starch, and NSCs. Considering the inconsistent responses of the different components of BVOCs to drought stress for different plant species, close attention should be paid to the effect of drought stress and global change on plant BVOCs emissions in the future.

First Report of Anthracnose caused by Colletotrichum siamense and C. gloeosporiodes on Cornus hongkongensis in China.

In summer 2021, severe anthracnose symptoms were found on the leaves of C. hongkongensis in Nanchang Institute of Technology (28°41'32.61"N, 116°1'53.75"E), with an incidence estimated at 25% to 55%. The lesion occurred mostly on young leaves with irregular reddish-brown with yellowish halos (Figure 1 A, B and C). Samples were collected and isolated. After the pathogenicity tests in the greenhouse, isolates of C. siamense and C. gloeosporiodes were selected for field experiment. To confirm pathogenicity, mycelial plugs of isolate SL13 and SH15 were applied on punctured leaves of C. hongkongensis using a sterile needle in field. Inoculation with only a PDA plug served as controls. All the leaves were covered with plastic bags for 48 h maintain high relative humidity. Seven days later, symptoms similar to those observed in the field developed on all leaves inoculated with isolated SL13 and SH15 (Figure 1 E and F), while the controls remained symptomless. Conidia of isolate SL13 and SH15 hyaline, were usually aseptate, sometimes becoming 1-septate with age, smooth-walled and cylindrical with both ends obtusely rounded, which were measured 13.68-17.41 × 4.38-6.09 µm (n = 30) (Figure1 J) and 11.01-16.15 × 3.520-5.09 µm (n=30) (Figure 1 K), respectively. Sequences were deposited in GenBank with accession numbers of OL658843 and OL858837 for ITS, OL677435 and OL961567 for ACT, OL961569 and OL961568 for GAPDH, OL677434 and OL677437 for TUB2, OL677436 and OL961570 for CHS1, respectively. Based on the phylogenetic tree analysis using IQ-TREE, isolate SL13 and SH15 was clustered with C. siamense and C. gloeosporiodes, respectively. C. siamense has been reported to cause anthracnose on C. hongkongensis (Wang et al., 2021). To our knowledge, the first report of C. gloeosporiodes and Colletotrichum siamense causing anthracnose on C. hongkongensis in China.

First Report of Brown Leaf Spot Caused by Neofusicoccum parvum on Photinia × fraseri Dress (Christmas berry) in China.

Christmas berry (Photinia × fraseri Dress), known as red tip photinia, is an important landscape color plant in South China (Zhu et al., 2021). In summer 2021, brown leaf spots of Christmas berry were observed with an incidence of 45-70% on the campus of Nanchang Institute of Technology, Jiangxi Province (28°41'32.61"N, 116°1'53.75"E), China. These spots have a negative influence on the photosynthetic activity and severely reduce the ornamental value of these plants. Lesions originally occurred on the margins or tips of the leaves as red patches (Figure 1 A) and then developed into irregular reddish-brown necrotic spots with yellow halos (Figure 1 B) that finally were grey lesions with dark brown ring circles surround with yellow halos (Figure 1 C). Ten leaf samples with typical symptoms from five plants were collected. The tissue between the healthy and necrotic area (ca. 5 mm × 5 mm) was cut with a sterile scalpel and surface sterilized in 70% alcohol for 45 s, followed by 2% NaClO for 2 min and washed in sterile deionized water three times, The sterilized leaf parts were placed on potato dextrose agar (PDA) and incubated at 25℃ for 3 to 5 days. A total of 28 fungal isolates were obtained from ten symptomatic leaves, which were classified into five species by morphological characteristics. Neofusicoccum was the genus with the highest isolation frequency (50%). For pathogenicity tests, healthy leaves of Christmas berry were surface-sterilized, wounded using a sterile needle and inoculated with mycelial plugs (6 mm in diameter) on the left site of the leaves. Five representative isolates were chosen and ten leaves were used for every isolate. The controls on the same leaves on the right side of the leaves were treated with sterile PDA plugs. All samples were placed in an artificial climate box (RH 90±3%, 27±1℃, 12 h light) for 3 days. Only the leaves inoculated with isolate NH7 showed dark brown leaf spots (Figure 1 D). The control leaves and those inoculated with the other four isolates remained symptomless. To confirm pathogenicity, mycelial plugs of isolate NH7 were applied on punctured leaves of Christmas berry in the field as the artificial climate box (Figure 1 E-H). Inoculation with a sterile PDA plug served as control. All the leaves were covered with plastic bags for 48 h to maintain high relative humidity. Seven days later, symptoms similar to those observed in the field developed on all leaves inoculated with isolated NH7, while the controls remained symptomless. To fulfill Koch's postulates, fungal isolates were reisolated from symptomatic leaves and identified by morphological and molecular characteristics. The colony of isolate NH7 developed aerial hyphae, which had a grey center surrounded by grey-white hyphae (Figure 1 I). Conidia were aseptate, primarily fusiform and measured 11.1-19.8 × 3.2-7.1 µm (n = 50) (Figure 1 J). For further confirmation of the identity, five genes, including ITS (White et al., 1990), RPB2 (Pavlic et al., 2009), tub2 (Glass & Donaldson, 1995), and tef1 (Carbone & Kohn, 1999) were sequenced. The sequences were deposited in GenBank (OL584411 for ITS, OL606622 for ACT, OL694623 for tub2, OM141481 for RPB2 and OM141482 for tef1), Based on the phylogenetic tree analysis using IQ-TREE, isolate NH7 clustered with Neofusicoccum parvum (Figure 2). N. parvum has been reported to cause leaf spot disease on different plants including Myristica fragrans (Jayakumar et al., 2011), Ginkgo biloba (Mirhosseini et al., 2014), Vitis heyneana (Wu et al., 2015), rubber tree (Liu et al., 2017) and Geodorum eulophioides (Du et al., 2021). To our knowledge, this is the first report of N. parvum causing leaf spot disease on Christmas berry in China. As one of the most widely planted ornamental shrubs in China, the detailed knowledge of the pathogens targeting Christmas berry is critical.

Sigma-1 Receptor Agonist TS-157 Improves Motor Functional Recovery by Promoting Neurite Outgrowth and pERK in Rats with Focal Cerebral Ischemia.

Sigma-1 (σ-1) receptor agonists are considered as potential treatment for stroke. TS-157 is an alkoxyisoxazole-based σ-1 receptor agonist previously discovered in our group. The present study describes TS-157 profile in a battery of tests for cerebral ischemia. Initial evaluation demonstrated the compound's safety profile and blood-brain barrier permeability, as well as its ability to induce neurite outgrowth in vitro. The neurite outgrowth was shown to be mediated via σ-1 receptor agonism and involves upregulation of ERK phosphorylation (pERK). In particular, TS-157 also significantly accelerated the recovery of motor function in rats with transient middle cerebral artery occlusion (tMCAO). Overall, the results herein support the notion that σ-1 receptor agonists are potential therapeutics for stroke and further animal efficacy studies are warranted.

Optical Kerr effect and third harmonic generation in topological Dirac/Weyl semimetal.

We study the nonlinear optical response generated by the massless Dirac quasiparticles residing around the topologically-protected Dirac/Weyl nodal points in three-dimensional (3D) topological semimetals. Analytical expressions of third-order interband nonlinear optical conductivities are obtained based on a quantum mechanical formalism which couples 3D Dirac fermions with multiple photons. Our results reveal that the massless Dirac fermions in three dimensions retains strong optical nonlinearity in terahertz frequency regime similar to the case of the two-dimensional Dirac fermions in graphene. At room temperature, the Kerr nonlinear refractive index and the harmonic generation susceptibility are found to be n2 = 10-11 ∼ 10-8 m2W-1 and χ(3) = 10-14 ∼ 10-8 m2V-2, respectively, in the few terahertz frequency regimes, which is comparable to graphene and orders of magnitudes stronger than many nonlinear crystals. Importantly, because 3D topological Dirac/Weyl semimetals possess bulk structural advantage not found in the strictly two-dimensional graphene, greater design flexibility and improved ease-of-fabrication in terms of photonic and optoelectronic device applications can be achieved. Our finding reveals the potential of 3D topological semimetals as a viable alternative to graphene for nonlinear optics applications.

Distinguishing plasmonic absorption modes by virtue of inversed architectures with tunable atomic-layer-deposited spacer layer.

We demonstrated the distinguishing between plasmonic absorption modes by exploiting an inversed architecture with tunable atomic-layer-deposited dielectric spacer layer. The dielectric spacer layer was manipulated between the bottom metal-nanoparticle monolayer and the upper metal film to inspect the contributions of metal nanoparticles and dielectric film in a step-by-step manner. The experimental and simulated differences between the two peak absorption positions (Δf) and between the corresponding half width at half maxima (Δw) confirmed the evolutions of gap plasmon and interference-enhanced local surface plasmon resonance absorption modes in the plasmonic metamaterial absorbers (PMAs), which were useful for understanding the underlying mechanism of amorphous PMAs.

How Does Physical Exercise Improve the Subjective Well-Being of the Chinese Adult Population? A Moderated Mediation Model.

Based on the 2017 data from the China General Social Survey (CGSS), the conditional process analysis method was used to explore the relationship between physical exercise and subjective well-being, as well as the mediating effect of social capital and the moderating effect of Internet use. This study found that the effect of physical exercise on subjective well-being includes both direct effects and indirect effects. Physical exercise directly and positively affects SWB and partially affects SWB through social networks as a mediating variable. Additionally, Internet use can moderate the direct effect of physical exercise on SWB and the mediating effect of social networks on the relationship between the two. As the frequency of Internet use increases, the link between physical exercise and social capital weakens, resulting in a decreased promotion effect on SWB. The results of this study further reveal the internal mechanism linking physical exercise and the improvement of SWB, which is of great significance for enhancing the accessibility of physical exercise facilities and promoting a healthy online lifestyle, ultimately leading to improved well-being among residents.

Molecular dynamics investigation on the interfacial thermal resistance between annealed pyrolytic graphite and copper.

Modern highly integrated microelectronic products often face the challenge of internal heat dissipation, leading to a significant decrease in their operational efficiency. Annealed Pyrolytic Graphite (APG), due to its superior thermal conductivity, has garnered attention from researchers. The interface thermal resistance between APG and supporting materials like copper significantly affects heat transfer during APG's operation. Existing studies rarely delve into the influence of factors such as the shape of APG material interfaces on thermal resistance from a microscopic perspective. In this paper, utilizing transient thermo-reflectance method and non-equilibrium molecular dynamics simulations, the interface thermal resistance of the APG-Cu structure was investigated under different conditions. The impact of parameters such as copper thickness, interface micro-surface morphology, and APG thickness on the calculated interface thermal resistance was examined. Simulation results revealed that copper thickness had a minor effect on the interface thermal resistance. This is because the phonon participation ratio remains unaffected by changes in the thickness of the copper layer. The interfacial thermal resistance beneath microscopically cylindrical copper surfaces was considerably lower than that of rectangular copper surfaces. This is because beneath the cylindrical surface, the enlarged interface contact area facilitates enhanced thermal transport between the interfaces. The computed results of the radial distribution function in the paper also indirectly validate this viewpoint. The magnitude of interfacial thermal resistance for different APG layers was influenced by the coupling effect of intermolecular forces and the layered stacking structure of APG. The interfacial thermal resistance under the condition of three layers of APG reaches its minimum value, which is 2.2 × 10-9 (K m2 W-1). Furthermore, from the phonon perspective, it is found that the interfacial thermal resistance with different numbers of APG layers is closely related to the localization or delocalization state of phonons. As the number of APG layers increased, the interface thermal resistance showed a trend of initial decrease followed by an increase, this is because the average phonon participation ratio increases and then decreases with the number of APG layers. The average phonon participation ratio reaches its maximum value of 0.45778 under the condition of three layers of APG.

Ultrafast anisotropic dynamics of hyperbolic nanolight pulse propagation.

Polariton pulses-transient light-matter hybrid excitations-traveling through anisotropic media can lead to unusual optical phenomena in space and time. However, studying these pulses presents challenges with their anisotropic, ultrafast, and nanoscale field variations. Here, we demonstrate the creation, observation, and control of polariton pulses, with in-plane hyperbolic dispersion, on anisotropic crystal surfaces by using a time-resolved nanoimaging technique and our developed high-dimensional data processing. We capture and analyze movies of distinctive pulse spatiotemporal dynamics, including curved ultraslow energy flow trajectories, anisotropic dissipation, and dynamical misalignment between phase and group velocities. Our approach enables analysis of polariton pulses in the wave vector time domain, demonstrating a time-domain polaritonic topological transition from lenticular to hyperbolic dispersion contours and the ability to study the polariton-induced time-varying optical forces. Our findings promise to facilitate the study of diverse space-time phenomena at extreme scales and drive advances in ultrafast nanoimaging.

Colossal Room-Temperature Terahertz Topological Response in Type-II Weyl Semimetal NbIrTe4.

The electromagnetic spectrum between microwave and infrared light is termed the "terahertz (THz) gap," of which there is an urgent lack of feasible and efficient room-temperature (RT) THz detectors. Type-II Weyl semimetals (WSMs) have been predicted to host significant RT topological photoresponses in low-frequency regions, especially in the THz gap, well addressing the shortcomings of THz detectors. However, such devices have not been experimentally realized yet. Herein, a type-II WSM (NbIrTe4 ) is selected to fabricate THz detector, which exhibits a photoresponsivity of 5.7 × 104  V W-1 and a one-year air stability at RT. Such excellent THz-detection performance can be attributed to the topological effect of type-II WSM in which the effective mass of photogenerated electrons can be reduced by the large tilting angle of Weyl nodes to further improve mobility and photoresponsivity. Impressively, this device shows a giant intrinsic anisotropic conductance (σmax /σmin  = 339) and THz response (Iph-max /Iph-min  = 40.9), both of which are record values known. The findings open a new avenue for the realization of uncooled and highly sensitive THz detectors by exploring type-II WSM-based devices.

Plasmonic semiconductor nanogroove array enhanced broad spectral band millimetre and terahertz wave detection.

High-performance uncooled millimetre and terahertz wave detectors are required as a building block for a wide range of applications. The state-of-the-art technologies, however, are plagued by low sensitivity, narrow spectral bandwidth, and complicated architecture. Here, we report semiconductor surface plasmon enhanced high-performance broadband millimetre and terahertz wave detectors which are based on nanogroove InSb array epitaxially grown on GaAs substrate for room temperature operation. By making a nanogroove array in the grown InSb layer, strong millimetre and terahertz wave surface plasmon polaritons can be generated at the InSb-air interfaces, which results in significant improvement in detecting performance. A noise equivalent power (NEP) of 2.2 × 10-14 W Hz-1/2 or a detectivity (D*) of 2.7 × 1012 cm Hz1/2 W-1 at 1.75 mm (0.171 THz) is achieved at room temperature. By lowering the temperature to the thermoelectric cooling available 200 K, the corresponding NEP and D* of the nanogroove device can be improved to 3.8 × 10-15 W Hz-1/2 and 1.6 × 1013 cm Hz1/2 W-1, respectively. In addition, such a single device can perform broad spectral band detection from 0.9 mm (0.330 THz) to 9.4 mm (0.032 THz). Fast responses of 3.5 µs and 780 ns are achieved at room temperature and 200 K, respectively. Such high-performance millimetre and terahertz wave photodetectors are useful for wide applications such as high capacity communications, walk-through security, biological diagnosis, spectroscopy, and remote sensing. In addition, the integration of plasmonic semiconductor nanostructures paves a way for realizing high performance and multifunctional long-wavelength optoelectrical devices.

Satellite-based ground PM2.5 estimation using a gradient boosting decision tree.

Fine particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5) is one of the major air pollutants risks to human health worldwide. Satellite-based aerosol optical depth (AOD) products are an effective metric for acquiring PM2.5 information, featuring broad coverage and high resolution, which compensate for the sparse and uneven distribution of existing monitoring stations. In this study, a gradient boosting decision tree (GBDT) model for estimating ground PM2.5 concentration directly from AOD products across China in 2017, integrating human activities and various natural variables was proposed. The GBDT model performed well in estimating temporal variability and spatial contrasts in daily PM2.5 concentrations, with relatively high fitted model (10-fold cross-validation) coefficients of determination of 0.98 (0.81), low root mean square errors of 3.82 (11.57) µg/m3, and mean absolute error of 1.44 (7.45) µg/m3. Seasonal examinations revealed that summer had the cleanest air with the highest estimation accuracies, whereas winter had the most polluted air with the lowest estimation accuracies. The model successfully captured the PM2.5 distribution pattern across China in 2017, showing high levels in southwest Xinjiang, the North China Plain, and the Sichuan Basin, especially in winter. Compared with other models, the GBDT model showed the highest performance in the estimation of PM2.5 with a 3-km resolution. This algorithm can be adopted to improve the accuracy of PM2.5 estimation with higher spatial resolution, especially in summer. In general, this study provided a potential method of improving the accuracy of satellite-based ground PM2.5 estimation.

Suppression of Photoinduced Surface Oxidation of Vanadium Dioxide Nanostructures by Blocking Oxygen Adsorption.

Controlling the surface is necessary to adjust the essential properties and desired functions of nanomaterials and devices. For nanostructured multivalent vanadium oxides, unwanted surface oxidation occurs at ambient atmosphere generally and needs to be suppressed or avoided. We describe the suppressed surface oxidation of VO2 nanostructures through blocking oxygen adsorption. During an enhanced photoinduced surface oxidation process, the increased oxidation states of vanadium in VO2 nanostructures are suppressed by the use of an inert atmosphere or coating. Intermediate oxidation states are observed, and an ALD-TiO2 coating has a good antioxidant capacity for preventing the formation of oxygen-enriched components. Such oxidation suppression is beneficial to improving the stability of VO2 nanostructures. Controllable surface oxidation helps us to understand the physical essentials of surface chemical reactions and achieve better control of surface functions and performances on correlated vanadium oxide nanostructures.

Photoelectrochemical Complexes of Fucoxanthin-Chlorophyll Protein for Bio-Photovoltaic Conversion with a High Open-Circuit Photovoltage.

Open-circuit photovoltage (Voc ) is among the critical parameters for achieving an efficient light-to-charge conversion in existing solar photovoltaic devices. Natural photosynthesis exploits light-harvesting chlorophyll (Chl) protein complexes to transfer sunlight energy efficiently. We describe the exploitation of photosynthetic fucoxanthin-chlorophyll protein (FCP) complexes for realizing photoelectrochemical cells with a high Voc . An antenna-dependent photocurrent response and a Voc up to 0.72 V are observed and demonstrated in the bio-photovoltaic devices fabricated with photosynthetic FCP complexes and TiO2 nanostructures. Such high Voc is determined by fucoxanthin in FCP complexes, and is rarely found in photoelectrochemical cells with other natural light-harvesting antenna. We think that the FCP-based bio-photovoltaic conversion will provide an opportunity to fabricate environmental benign photoelectrochemical cells with high Voc , and also help improve the understanding of the essential physics behind the light-to-charge conversion in photosynthetic complexes.

[Effect of Manual Acupuncture Stimulation of Single Acupoint or Acupoints Combination on Intestinal Movement in Slow Transit Constipation Mice].

OBJECTIVE: To observe the effect of acupuncture stimulation of different acupoints or acupoint groups on intestinal locomotor in slow transit constipation (STC) mice, so as to provide experimental evidence for demonstrating the synergic function of acupoint combination. METHODS: A total of 190 Kunming mice were randomized into 19 groups:normal control, model, uni-"Quchi" (LI 11), uni-"Shangjuxu" (ST 37), uni-"Tianshu"(ST 25), and uni-"Dachangshu"(BL 25) groups, for analyzing the effect of single acupoint; normal control, model, uni-ST 25+uni-BL 25, uni-LI 11+uni-ST 37, bi-ST 25, bi-BL 25, bi-LI 11, and bi-ST 37 groups, for comparing the effect between single acupoint and two acupoints combination; normal control, model, bi-ST 25+bi-BL 25, bi-LI 11+bi-ST 37, and uni-LI 11+uni-ST 37+uni-ST 25 +uni-BL 25 groups, for comparing the effect between four acupoints and two acupoints combinations (10 mice/group). The STC model was established by intragastric administration of compound diphenoxylate suspension (1 mg/100 g), once daily for 2 days. Manual acupuncture needle stimulation (200 twirling times/min for 1 min) was applied to the abovementioned unilateral or bilateral acupoints twice daily for 7 times. The first defecation time, the defecation grain number in 12 h and the intestinal propulsion rate were determined using activated carbon gavage. RESULTS: Compared with the normal group, the first defecation time was significantly increased in the STC model group (P<0.01), while the 12 h defecation grain number and the intestinal propulsion rate were considerably decreased in the model group (P<0.01). After manual acupuncture intervention, the first defecation time was notably shortened in the uni-LI 11, uni-ST 37, uni-ST 25, uni-BL 25, bi-ST 25, bi-BL 25, bi-LI 11, bi-ST 37, uni-ST 25+uni-BL 25, uni-LI 11+uni-ST 37, bi-ST 25+bi-BL 25, bi-LI 11+bi-ST 37 and the uni-ST 25+uni-BL 25+uni-LI 11+uni-ST 37 groups compared with the model group (P<0.05), while both the 12 h defecation grain number and intestinal propulsion rate were considerably increased in the abovementioned 13 acupuncture groups (P<0.05, P<0.01). The effects of uni-ST 25+uni-BL 25 and uni-LI 11+uni-ST 37 were significantly superior to those of bi-ST 25, bi-BL 25, bi-LI 11 and bi-ST 37 groups, and those of the uni-ST 25+uni-BL 25+uni-LI 11+uni-ST 37 group were markedly superior to those of bi-ST 25+bi-BL 25 and bi-LI 11+bi-ST 37 groups in shortening the first defecation time and in increasing the 12 h defecation grain number and intestinal propulsion rate (P<0.05). CONCLUSIONS: Acupuncture stimulation of LI 11, ST 37, ST 25 and BL 25 can improve constipation in STC mice, and the effect of two acupoints combination is significantly superior to that of the corresponding bilateral single acupoint, and that of the 4 unilateral single acupoint combination is obviously superior to that of two bilateral acupoints combination, suggesting a synergistic action of acupuncture stimulation.