375 research outputs found

    Magnetic Suspension and Self-pitch for Vertical-axis Wind Turbines

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    Effects of different remifentanil doses on the stress reaction and BIS value of video laryngoscope-guided tracheal intubation

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    Purpose: To explore the affinity of different remifentanil doses for  intravenous anesthesia in video laryngoscope-guided tracheal intubation.Methods: Eighty patients who required anesthesia for elective non-ophthalmic surgery were included. They were divided into four groups (A, B, C and D) and received a different dose of either 1, 1.5, or 2 μg/kg remifentanil or a dose of 2 μg/kg fentanyl, respectively. An anesthetic state was achieved and maintained by administration of 3 - 5 mg/kg propofolum and 0.1 - 0.3 mg/kg remifentanil. The mean value of the various indices, including arterial pressure (MAP), bispectral index and heart rate (HR) wererecorded prior to anesthesia induction (T0), prior to intubation (T1),  instantly before intubation (T2), and at 1 (T3), 3 (T4) and 5 (T5) after the intubation. Cortisol concentration was measured at T0, T1 and T5.Results: Remifentanil (1 μg/kg) induced a moderate increase in HR and MAP at T3 compared with fentanyl. HR and MAP in the lower dose group were significantly higher than those in groups B and C at T3. Compared to T1, the concentrations of cortisol decreased after anesthesia and then significantly increased during tracheal intubation. Cortisol concentration in group B was the lowest at T5.Conclusion: The most effective concentrations of remifentanil are 1 and 1.5 μg/kg for anesthesia induction and tracheal intubation, respectively.Keywords: Remifentanil, Stress reaction, Bispectral index, Video laryngoscope, Tracheal intubatio

    Complexation of Z-ligustilide with hydroxypropyl-β-cyclodextrin to improve stability and oral bioavailability

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    To improve the stability and oral bioavailability of Z-ligustilide (LIG), the inclusion complex of LIG with hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared by the kneading method and characterized by UV-Vis spectroscopy, differential thermal analysis (DTA) and Fourier transform infrared (FTIR) spectroscopy. LIG is capable of forming an inclusion complex with HP-β-CD and the stoichiometry of the complex was 1:1. Stability of the inclusion complex against temperature and light was greatly enhanced compared to that of free LIG. Further, oral bioavailability of LIG and the inclusion complex in rats were studied and the plasma drug concentration-time curves fitted well with the non-compartment model to estimate the absolute bioavailability, which was 7.5 and 35.9 %, respectively. In conclusion, these results show that LIG/HP-β-CD complexation can be of great use for increasing the stability and biological efficacy of LIG

    The impact of farm size on agricultural sustainability

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    Farm size plays a critical role in agricultural sustainability. This may have far-reaching consequences for the economic and environmental performance of agricultural production, resulting, for instance, in an excessive use of mineral fertilizers. However, the magnitude of such effects and their main causes are not well understood, while being essential for effective policy development, especially for countries like China where the agricultural sector is still largely dominated by smallholder farms. In this paper, we review the current understanding of how farm size affects agricultural sustainability using China's crop farming as an example from economic, environment and social aspects. We analyze impacts from both a Chinese and a global perspective to identify intervention points to improve agricultural performance. We found that increasing farm size has a positive impact on farmer’s net profit, as well as economic, technical and labor efficiency with mean coefficients 0.005, 0.02 and 2.25 in economic performance, respectively. Nevertheless, the relationships between farm size and overall productivity, total factor productivity and allocative efficiency are still not well understood and therefore require more research. Meanwhile, increase in farm size is associated with statistically significant decrease in fertilizer and pesticide use per hectare, showing clear benefits for environmental protection. In line with the experiences documented for the evolution of agricultural practices in developed countries, the expansion of large-scale farming is a critical path for modernizing agricultural production and ensuring sustainable food production from the social perspective. Measures concerning farm size should be implemented in an interaction between farmers and the government to promote the green development of agriculture

    A Subabdominal MRI Image Segmentation Algorithm Based on Multi-Scale Feature Pyramid Network and Dual Attention Mechanism

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    This study aimed to solve the semantic gap and misalignment issue between encoding and decoding because of multiple convolutional and pooling operations in U-Net when segmenting subabdominal MRI images during rectal cancer treatment. A MRI Image Segmentation is proposed based on a multi-scale feature pyramid network and dual attention mechanism. Our innovation is the design of two modules: 1) a dilated convolution and multi-scale feature pyramid network are used in the encoding to avoid the semantic gap. 2) a dual attention mechanism is designed to maintain spatial information of U-Net and reduce misalignment. Experiments on a subabdominal MRI image dataset show the proposed method achieves better performance than others methods. In conclusion, a multi-scale feature pyramid network can reduce the semantic gap, and the dual attention mechanism can make an alignment of features between encoding and decoding.Comment: 19 pages,9 figure

    (2E,6E)-2,6-Bis(4-ethoxy­benzyl­idene)cyclo­hexa­none

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    The title compound, C24H26O3, was prepared by the condensation reaction of 4-ethoxy­benzaldehyde with cyclo­hexa­none. The mol­ecule has crystallographic mirror symmetry and exhibits a butterfly-shaped geometry, with a dihedral angle of 5.46 (1)° between the two benzene rings. Weak inter­molecular C—H⋯π inter­actions help stabilize the crystal structure

    A new Neocalamites (Sphenophyta) with prickles and attached cones from the Upper Triassic of China

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    Remains of the extinct sphenophyte (horsetail) . Neocalamites are most widespread in the Middle-Upper Triassic and are typically represented by stem and leaf fragments. Here we report on spectacular new finds of . Neocalamites from the Late Triassic Yangcaogou Formation in Liaoning Province, China that include bedding surfaces dominated by nearly complete aerial stems with attached leaf whorls and rare bractless cones. They reveal a monopodial growth habit for the stems, which are covered with downward projecting prickles that probably provided protection against herbivores. These features provide the basis for a new proposed species, . Neocalamites horridus. The nodes bear whorls of very long leaves mainly free to their bases, and one specimen bears an attached cone on a long peduncle. Identical dispersed cones have also been recovered. The leaves of adjacent monopodial stems most likely interlocked to support growth in large stands akin to the role now played by branches in large modern . Equisetum species. The new Chinese . Neocalamites is among the most confidently reconstructed species, and indicates a greater diversity of sphenophyte morphology during the Mesozoic than previously realized.Fil: Zan, Shuqin. Geological Museum Of China; ChinaFil: Axsmith, Brian J.. University of Alabama at Birmingahm; Estados UnidosFil: Escapa, Ignacio Hernán. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fraser, Nicholas. National Museum Of Scotland; Reino UnidoFil: Liu, Feng Xiang. Geological Museum Of China; ChinaFil: Xing, De-He. Shenyang Institute Of Geology And Mineral Resources; Chin

    Susceptibility of cervical cancer to dihydroartemisinin-induced ferritinophagy-dependent ferroptosis

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    The clinical therapeutics of cervical cancer is limited due to the drug resistance and metastasis of tumor. As a novel target for antitumor therapy, ferroptosis is deemed to be more susceptible for those cancer cells with resistance to apoptosis and chemotherapy. Dihydroartemisinin (DHA), the primary active metabolites of artemisinin and its derivatives, has exhibited a variety of anticancer properties with low toxicity. However, the role of DHA and ferroptosis in cervical cancer remained unclear. Here, we showed that DHA could time-dependently and dose-dependently inhibit the proliferation of cervical cancer cells, which could be alleviated by the inhibitors of ferroptosis rather than apoptosis. Further investigation confirmed that DHA treatment initiated ferroptosis, as evidenced by the accumulation of reactive oxygen species (ROS), malondialdehyde (MDA) and liquid peroxidation (LPO) levels and simultaneously depletion of glutathione peroxidase 4 (GPX4) and glutathione (GSH). Moreover, nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy was also induced by DHA leading to subsequent increases of intracellular labile iron pool (LIP), exacerbated the Fenton reaction resulting in excessive ROS production, and enhanced cervical cancer ferroptosis. Among them, we unexpectedly found that heme oxygenase-1 (HO-1) played an antioxidant role in DHA-induced cell death. In addition, the results of synergy analysis showed that the combination of DHA and doxorubicin (DOX) emerged a highly synergistic lethal effect for cervical cancer cells, which was related also to ferroptosis. Overall, our data revealed the molecular mechanisms that DHA triggered ferritinophagy-dependent ferroptosis and sensitized to DOX in cervical cancer, which may provide novel avenues for future therapy development
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