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394 result(s) for "Shi, Yupeng"
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Do political connections facilitate or inhibit firms’ digital transformation? Evidence from China’s A-share private listed companies
Given the advent of the digital era, digital transformation has become necessary for enterprise development. Political connections are the most important resources for enterprise development in most countries. However, the impact of political connections on corporate digital transformation has yet to be verified. This study uses ERNIE, a large language model, to construct a measurement of corporate digital transformation from the perspective of digital technology application through a textual analysis of the annual reports of A-share privately listed companies from 2008 to 2020 and analyzes the impact of political connections on corporate digital transformation and its mechanism of action. The findings demonstrate that political connections have a significant inhibitory effect on corporate digital transformation. This conclusion still holds after a series of robustness and endogeneity tests. The mechanism analyses demonstrate that political connections primarily affect corporate digital transformation through three mechanisms: weakening risk, inhibiting innovation, and enhancing resource crowding. We theoretically expand the understanding of the economic impact of political connections and provide new ideas for accelerating enterprise digital transformation from the perspective of policy makers.
Facile synthesis of Gd/Ru-doped fluorescent carbon dots for fluorescent/MR bimodal imaging and tumor therapy
Functional metal doping endows fluorescent carbon dots with richer physical and chemical properties, greatly expanding their potential in the biomedical field. Nonetheless, fabricating carbon dots with integrated functionality for diagnostic and therapeutic modalities remains challenging. Herein, we develop a simple strategy to prepare Gd/Ru bimetallic doped fluorescent carbon dots (Gd/Ru-CDs) via a one-step microwave-assisted method with Ru(dcbpy) 3 Cl 2 , citric acid, polyethyleneimine, and GdCl 3 as precursors. Multiple techniques were employed to characterize the morphology and properties of the obtained carbon dots. The Gd/Ru-CDs are high mono-dispersity, uniform spherical nanoparticles with an average diameter of 4.2 nm. Moreover, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) confirmed the composition and surface properties of the carbon dots. In particular, the successful doping of Gd/Ru enables the carbon dots not only show considerable magnetic resonance imaging (MRI) performance but also obtain better fluorescence (FL) properties, especially in the red emission area. More impressively, it has low cytotoxicity, excellent biocompatibility, and efficient reactive oxygen species (ROS) generation ability, making it an effective imaging-guided tumor treatment reagent. In vivo experiments have revealed that Gd/Ru-CDs can achieve light-induced tumor suppression and non-invasive fluorescence/magnetic resonance bimodal imaging reagents to monitor the treatment process of mouse tumor models. Thus, this simple and efficient carbon dot manufacturing strategy by doping functional metals has expanded avenues for the development and application of multifunctional all-in-one theranostics.
CR-MSNet: a dual-branch multi-scale attention network for multi-label chest X-ray classification
Multi-label disease diagnosis in chest X-rays necessitates simultaneous consideration of both global organ structures and local lesion characteristics. However, current methodologies primarily utilize single-branch architectures and lack effective attention guidance mechanisms, which complicates the balance between global context and local details. Furthermore, multi-label datasets for chest X-rays often suffer from significant class imbalance. We propose CR-MSNet, a dual-branch multi-scale attention network designed for multi-label chest X-ray classification. The global branch is constructed using CoAtNet-2-rw to capture holistic semantic representations, while the local branch employs a residual convolutional neural network to extract detailed lesion features. We incorporate a cross-attention mechanism to facilitate adaptive interaction and information exchange between global and local representations. Additionally, we propose a Parallel Multi-Scale Channel-Spatial Attention (PMS-CSA) module to enhance both key semantic channels and potential lesion regions, thereby increasing the discriminative power of feature representations. A two-stage training strategy with an adjusted loss function is implemented to effectively alleviate the detrimental effects of class imbalance on model performance. Experimental results indicate that CR-MSNet achieves a macro-average AUC of 0.847 on the ChestX-ray14 dataset, confirming its effectiveness and potential for application in multi-label classification tasks for chest X-rays. By seamlessly integrating a dual-branch architecture with multi-scale attention mechanisms, this study confirms the critical role of attention-guided feature interactions in reconciling global and local representations.
Multifunctional Hf/Mn-TCPP Metal-Organic Framework Nanoparticles for Triple-Modality Imaging-Guided PTT/RT Synergistic Cancer Therapy
Recent studies have validated and confirmed the great potential of nanoscale metal-organic framework (NMOF) in the biomedical field, especially in improving the efficiency of cancer diagnosis and therapy. However, most previous studies only utilized either the metal cluster or the organic ligand of the NMOF for cancer treatments and merely reported limited theranostic functions, which may not be optimized. As a highly designable and easily functionalized material, prospective rational design offers a powerful way to extract the maximum benefit from NMOF for cancer theranostic applications. A NMOF based on hafnium (Hf) cluster and Mn(III)-porphyrin ligand was rational designed and synthesized as a high-performance multifunctional theranostic agent. The folic acid (FA) was modified on the NMOF surface to enhance the cancer targeting efficacy. The proposed \"all-in-one\" FA-Hf-Mn-NMOF (fHMNM) was characterized and identified using various analytical techniques. Then, in vitro and in vivo studies were performed to further explore the effects of fHMNM both as the magnetic resonance imaging (MRI)/computed tomography (CT)/photoacoustic imaging (PAI) contrast agent and as the photothermal therapy (PTT)/radiotherapy (RT) agent. A tumour targeting multifunctional fHMNM was successfully synthesized with high performance for MRI/CT/PAI enhancements and image-guided PTT/RT synergistic therapy properties. Compared with the current clinical CT and MR contrast agents, the X-ray attenuation and T relaxation rate of this integrated nanosystem increased 1.7-fold and 3-5-fold, respectively. More importantly, the catalase-like Mn(III)-porphyrin ligand can decompose H O into O in tumour microenvironments to improve the synergistic treatment efficiency of PTT and RT. Significant tumour growth inhibition was achieved in mouse cancer models without obvious damage to the other organs. This work highlights the potential of fHMNM as an easily designable material for biomedical applications, could be an effective tool for in vivo detection and subsequent treatment of tumour.
Optimizing Excavation by Excavators Based on an Analysis of Digging Resistance Characteristics
Accurately determining digging resistance during bucket–soil interaction is crucial for optimizing excavator working devices and power systems. To address measurement difficulties, a numerical simulation model based on the arbitrary Lagrangian–Eulerian (ALE) method was established and verified through excavation tests. Through orthogonal experiments, the influence of excavation parameters was studied, and the optimal compound digging trajectory was determined. The results show that increasing the excavation angle from 36° to 48° decreases the X-direction resistance and moment by 39.48% and 38.85%, respectively, though specific energy consumption (SE) increases. Additionally, optimizing arm movement speed reduces the X-direction resistance and moment. While ensuring the bucket load factor is suitable, reducing arm speed and a horizontal soil push during compound excavation effectively decreases SE. Finally, the optimal balance of digging resistance and SE can be achieved with a 300 mm bucket hydraulic cylinder displacement, a 1.5 s interval for initial arm and bucket movements, and an arm-to-bucket speed ratio of 5.5 for hydraulic cylinders.
Synthesis of fluorescent nanoprobe with simultaneous response to intracellular pH and Zn2+ for tumor cell distinguishment
A novel dual-functional nanoprobe was designed and synthesized by facile assembly of quinoline derivative (PEIQ) and meso-tetra (4-carboxyphenyl) porphine (TCPP) via electrostatic interaction for simultaneous sensing of fluorescence of Zn 2+ and pH. Under the single-wavelength excitation at 400 nm, this nanoprobe not only exhibits “OFF-ON” green fluorescence at 512 nm by specific PEIQ-Zn 2+ chelation, but also presents red fluorescence enhancement at 654 nm by H + -triggered TCPP release. The nanoprobe demonstrated excellent sensing performance with a good linear range (Zn 2+ , 1–40 μM; pH, 5.0–8.0), low detection limit (Zn 2+ , 0.88 μM), and simultaneous response towards Zn 2+ and pH in pure aqueous solution within 2 min. More importantly, this dual-functional nanoprobe demonstrates the capability of discerning cancerous cells from normal cells, as evidenced by the fact that cancerous HepG2 cells in tumor microenvironment exhibit substantially higher red fluorescence and significantly lower green fluorescence than normal HL-7702 cells. The simultaneous, real-time fluorescence imaging of multiple analytes in a living system could be significant for cell analysis and tracking, cancer diagnosis, and even fluorescence-guided surgery of tumors. Graphical abstract
A role for the RNA-binding protein MOS2 in microRNA maturation in Arabidopsis
microRNAs (miRNAs) play important roles in the regulation of gene expression. In Arabidopsis, mature miRNAs are processed from primary miRNA transcripts (pri-miRNAs) by nuclear HYL1/SE/DCL1 complexes that form Dicing bodies (D-bodies). Here we report that an RNA-binding protein MOS2 binds to pri-miRNAs and is involved in efficient processing of pri-miRNAs. MOS2 does not interact with HYL1, SE, and DCL1 and is not localized in D- bodies. Interestingly, in the absence of MOS2, the recruitment of pri-miRNAs by HYL1 is greatly reduced and the localization of HYL1 in D-bodies is compromised. These data suggest that MOS2 promotes pri-miRNA processing through facilitating the recruitment of pri-miRNAs by the Dicing complexes.
Design and Experiment of Bare Seedling Planting Mechanism Based on EDEM-ADAMS Coupling
In traditional scallion cultivation, the bare-root transplanting method—which involves direct seeding, seedling raising in the field, and lifting—is commonly adopted to minimize seedling production costs. However, during the mechanized transplanting of bare-root scallion seedlings, practical problems such as severe seedling damage and poor planting uprightness exist. In this paper, the Hertz–Mindlin with Bonding contact model was used to establish the scallion seedling model. Combined with the Plackett–Burman experiment, steepest ascent experiment, and Box–Behnken experiment, the bonding parameters of scallion seedlings were calibrated. Furthermore, the accuracy of the scallion seedling model parameters was verified through the stress–strain characteristics observed during the actual loading and compression process of the scallion seedlings. The results indicate that the scallion seedling normal/tangential contact stiffness, scallion seedling normal/tangential ultimate stress, and scallion Poisson’s ratio significantly influence the mechanical properties of scallion seedlings. Through optimization experiments, the optimal combination of the above parameters was determined to be 4.84 × 109 N/m, 5.64 × 107 Pa, and 0.38. In this paper, the flexible planting components of scallion seedlings were taken as the research object. Flexible protrusions were added to the planting disc to reduce the damage rate of scallion seedlings, and an EDEM-ADAMS coupling interaction model between the planting components and scallion seedlings was established. Based on this model, optimization and verification were carried out on the key components of the planting components. Orthogonal experiments were conducted with the contact area between scallion seedlings and the disc, rotational speed of the flexible disc, furrow depth, and clamping force on scallion seedlings as experimental factors, and with the uprightness and damage status of scallion seedlings as evaluation criteria. The experimental results showed that when the contact area between scallion seedlings and the disc was 255 mm2, the angular velocity was 0.278 rad/s, and the furrow depth was 102.15 mm, the performance of the scallion planting mechanism was optimal. At this point, the uprightness of the scallion seedlings was 94.80% and the damage rate was 3%. Field experiments were carried out based on the above parameters. The results indicated that the average uprightness of transplanted scallion seedlings was 93.86% and the damage rate was 2.76%, with an error of less than 2% compared with the simulation prediction values. Therefore, the parameter model constructed in this paper is reliable and effective, and the designed and improved transplanting mechanism can realize the upright and low-damage planting of scallion seedlings, providing a reference for the low-damage and high-uprightness transplanting operation of scallions.
Efficacy of Mini Wheel-Driven Sweet Potato Transplanting Machine for Mulched Raised Beds
The mechanized transplanting of sweet potato slips onto mulched raised beds in China’s Huang-Huai-Hai region faces significant challenges due to fragmented smallholder farms and the specific agronomic requirement of “boat-shaped” horizontal planting. To address this gap, this study aimed to develop a compact, cost-effective transplanter that meets the “boat-shaped” planting agronomy and adapts to small plots. We designed the 2CGX-1 mini wheel-driven transplanter coupled with a tractor. This machine features a compact chassis (<1.5 m length) for enhanced maneuverability on small plots, a novel five-bar taking-planting mechanism optimized for boat-shaped placement (achieving a stem-soil angle of 56.2° and planting depth of 110 mm), and an integrated spring buffer system. Transmission design ensures precise synchronization between the dual-chain seedling feeding mechanism and planting actions, allowing plant spacing adjustment from 18 to 30 cm. Coupled Adams–EDEM simulations demonstrated that the buffer system reduces maximum resistance on the clip fingers by 37.8% when encountering obstacles. Field validation under optimal parameters (0.55 km/h operating speed, 30 plants/min transplanting frequency) showed high consistency: average planting depth 101.3 mm (SD 1.38), plant spacing 330.3 mm (SD 11.24), seedling length under the film 185 mm (SD 3.65), and stem-soil angle 47.9° (SD 3.41), with qualification rates exceeding 91.9% for all key parameters except submerged length (82.5%). Compared with manual planting (≤0.1 ha/day per person, labor cost > ¥800/ha), this transplanter achieves a daily operational efficiency of ~0.35 ha/day (calculated by 0.55 km/h speed × 0.8 m working width × 8 h daily working time). Meanwhile, the consistency of its key planting indicators and the planting qualification rate are significantly superior to those of manual planting, while improving operational quality and significantly reducing labor cost input. Deviations in individual indicators mainly stem from planting positioning deviations induced by terrain undulations in hilly test areas, and sweet potato seedlings’ tendency to fall off during clamping due to mechanical vibration. However, these errors are within the acceptable agricultural operation range and do not compromise the machine’s overall compliance with agronomic requirements. The transplanter effectively meets agronomic requirements while offering a cost-effective, adapted solution for small-scale sweet potato production systems, significantly advancing mechanization capabilities for mulched cultivation.
Integrating vortex wave generation with broadband microwave attenuation using a multi-layer cascaded metasurface
Developing electromagnetic metamaterials that simultaneously offer broadband response, a thin profile, and multifunctional capabilities remains a key challenge in stealth technology. Based on the Pancharatnam–Berry (PB) phase principle, this study proposes a multilayer cascaded geometric phase metasurface. By rotating the meta-atoms to introduce a controllable phase gradient, the metasurface efficiently converts incident circularly polarized waves into co-polarized reflected vortex waves, while leveraging electromagnetic coupling and resonance characteristics between the multilayer structures to achieve broadband energy dissipation. Experimental results demonstrate that this merely 2.72 mm thick multilayer cascaded structure achieves an effective absorption bandwidth of 7.9 GHz (8.1–16.0 GHz), representing a threefold increase over a single-layer design, and exhibits excellent radar cross-section (RCS) reduction performance. Near field and scattering confirm vortex wave generation with specific topological charges, revealing the intrinsic physical mechanism underlying broadband absorption and stealth through energy scattering across a wide angular domain. This study provides new insights for addressing the technical challenges of broadband and multifunctional absorption materials, laying an important foundation for the development of next-generation intelligent stealth metamaterials.