115 research outputs found

    FRICTION TEST AND PARAMETER ANALYSIS OF PRESTRESSED CONCRETE CONTINUOUS BEAM BRIDGE

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    The prestressed ducts of prestressed concrete continuous girder bridges are usually three-dimensionally distributed and long in length. The control of prestress loss during construction is very important. In order to ensure the effect of prestress tensioning, the test and analysis of friction parameters of prestressed ducts are particularly important. Based on the tension process of a prestressed concrete continuous beam bridge, the initial tension stress, loading time and channel friction parameters of the prestressed concrete continuous beam bridge are tested by field tests. Combined with the measured friction parameters, the finite element software Midas / Civil is used to analyse the influence of friction parameters on the mechanical properties of prestressed concrete continuous beam bridge. The results show that when the prestressed steel with bending angle not more than 40° and length not more than 70 m is stretched, the initial tension stress is suggested to be set as 20 % of the tension control force and the loading time is 5 min. The measured tunnel friction parameters are larger than the standard value, and the tension control force should be adjusted during the formal tension construction;The deflection of the key section of the main beam increases with the increase of the friction parameters, and the roof stress decreases with the increase of the friction parameters. The change of channel deviation coefficient has a greater impact on the deflection and roof stress than the change of friction coefficient

    Neural Correlates of Attentional Modulation of Prepulse Inhibition

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    Prepulse inhibition (PPI) refers to the suppression of the startle reflex when the intense startling stimulus is shortly (20–500 ms) preceded by a weak non-startling stimulus (prepulse). Although the main neural correlates of PPI lie in the brainstem, previous research has revealed that PPI can be top-down modulated by attention. However, in the previous attend-to-prepulse PPI paradigm, only continuous prepulse but not discrete prepulse (20 ms) could elicit attentional modulation of PPI. Also, the relationship between the attentional enhancement of PPI and the changes in early cortical representations of prepulse signals is unclear. This study develops a novel attend-to-prepulse PPI task, when the discrete prepulse is set at 150 ms at a lead interval of 270 ms, and reveals that the PPI with attended prepulse is larger than the PPI with ignored prepulse. In addition, the early cortical representations (N1/P2 complex) of the prepulse show dissociation between the attended and ignored prepulse. N1 component is enhanced by directed attention, and the attentional increase of the N1 component is positively correlated with the attentional enhancement of PPI, whereas the P2 component is not affected by attentional modulation. Thus, directed attention to the prepulse can enhance both PPI and the early cortical representation of the prepulse signal (N1)

    Nanoparticle-enhanced PD-1/PD-L1 targeted combination therapy for triple negative breast cancer

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    Breast cancer with triple-negative subtype (TNBC) presents significant challenges with limited treatment options and a poorer prognosis than others. While PD-1/PD-L1 checkpoint inhibitors have shown promise, their efficacy in TNBC remains constrained. In recent years, nanoparticle (NP) technologies offer a novel approach to enhance cancer therapy by optimizing the tumor microenvironment and augmenting chemo- and immunotherapy effects in various preclinical and clinical settings. This review discusses recent investigations in NP strategies for improving PD-1/PD-L1 blockade-based combination therapy for TNBC. Those include single or multi-therapeutic NPs designed to enhance immunogenicity of the tumor, induce immunogenic cell death, and target immunosuppressive elements within the tumor microenvironment. The investigations also include NPs co-loaded with PD-L1 inhibitors and other therapeutic agents, leveraging targeted delivery and synergistic effects to maximize efficacy while minimizing systemic toxicity. Overall, NP approaches represent a promising avenue for enhancing PD-1/PD-L1 checkpoint blockade-based combination therapy in TNBC and encourage further developmental studies

    Performance of Combined Process of Air Flotation- Sedimentation - Biological Contact Oxidation - Membrane Biological Reactor Treating Heavy Oil Wastewater

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    A study of the treatment of heavy oil wastewater was carried out using the combined process of dissolved air flotation-sedimentation- biological contact oxidation - ultra-filtration membrane. When hydraulic retention times (HRT) was 18h, removal rates of COD, oil and suspended substance (SS) approached at 73~75%, 98%~99% and 100%, respectively. The diversity of bacterias was increased after air flotation, the betaproteobacteria dominated after enriched bacterias of BW-1, BW-2, BW-3,WSW-4,1-2-1 and 3-2-1 were added to contact oxidation tank. The combined process provided a suitable process in dealing with the complex heavy oil wastewater

    Diurnal regulation of SDG2 and JMJ14 by circadian clock oscillators orchestrates histone modification rhythms in Arabidopsis

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    Background: Circadian rhythms modulate growth and development in all organisms through interlocking transcriptional-translational feedback loops. The transcriptional loop involves chromatin modifications of central circadian oscillators in mammals and plants. However, the molecular basis for rhythmic epigenetic modifications and circadian regulation is poorly understood. Results: Here we report a feedback relationship between diurnal regulation of circadian clock genes and histone modifications in Arabidopsis. On one hand, the circadian oscillators CCA1 and LHY regulate diurnal expression of genes coding for the eraser (JMJ14) directly and writer (SDG2) indirectly for H3K4me3 modification, leading to rhythmic H3K4me3 changes in target genes. On the other hand, expression of circadian oscillator genes including CCA1 and LHY is associated with H3K4me3 levels and decreased in the sdg2 mutant but increased in the jmj14 mutant. At the genome-wide level, diurnal rhythms of H3K4me3 and another histone mark H3K9ac are associated with diurnal regulation of 20-30% of the expressed genes. While the majority (86%) of H3K4me3 and H3K9ac target genes overlap, only 13% of morning-phased and 22% of evening-phased genes had both H3K4me3 and H3K9ac peaks, suggesting specific roles of different histone modifications in diurnal gene expression. Conclusions: Circadian clock genes promote diurnal regulation of SDG2 and JMJ14 expression, which in turn regulate rhythmic histone modification dynamics for the clock and its output genes. This reciprocal regulatory module between chromatin modifiers and circadian clock oscillators orchestrates diurnal gene expression that governs plant growth and development

    Superconductivity in a new layered cobalt oxychalcogenide Na6_{6}Co3_{3}Se6_{6}O3_{3} with a 3d5d^{5} triangular lattice

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    Unconventional superconductivity in bulk materials under ambient pressure is extremely rare among the 3dd transition-metal compounds outside the layered cuprates and iron-based family. It is predominantly linked to highly anisotropic electronic properties and quasi-two-dimensional (2D) Fermi surfaces. To date, the only known example of the Co-based exotic superconductor was the hydrated layered cobaltate, Nax_{x}CoO2_{2}\cdot yH2_{2}O, and its superconductivity is realized in the vicinity of a spin-1/2 Mott state. However, the nature of the superconductivity in these materials is still an active subject of debate, and therefore, finding new class of superconductors will help unravel the mysteries of their unconventional superconductivity. Here we report the discovery of unconventional superconductivity at \sim 6.3 K in our newly synthesized layered compound Na6_{6}Co3_{3}Se6_{6}O3_{3}, in which the edge-shared CoSe6_{6} octahedra form [CoSe2_{2}] layers with a perfect triangular lattice of Co ions. It is the first 3dd transition-metal oxychalcogenide superconductor with distinct structural and chemical characteristics. Despite its relatively low TcT_{c}, material exhibits extremely high superconducting upper critical fields, μ0Hc2(0)\mu_{0}H_{c2}(0), which far exceeds the Pauli paramagnetic limit by a factor of 3 - 4. First-principles calculations show that Na6_{6}Co3_{3}Se6_{6}O3_{3} is a rare example of negative charge transfer superconductor. This new cobalt oxychalcogenide with a geometrical frustration among Co spins, shows great potential as a highly appealing candidate for the realization of high-TcT_{c} and/or unconventional superconductivity beyond the well-established Cu- and Fe-based superconductor families, and opened a new field in physics and chemistry of low-dimensional superconductors

    Association between dietary habits and the risk of migraine: a Mendelian randomization study

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    ObjectiveThe important contribution of dietary triggers to migraine pathogenesis has been recognized. However, the potential causal roles of many dietary habits on the risk of migraine in the whole population are still under debate. The objective of this study was to determine the potential causal association between dietary habits and the risk of migraine (and its subtypes) development, as well as the possible mediator roles of migraine risk factors.MethodsBased on summary statistics from large-scale genome-wide association studies, we conducted two-sample Mendelian randomization (MR) and bidirectional MR to investigate the potential causal associations between 83 dietary habits and migraine and its subtypes, and network MR was performed to explore the possible mediator roles of 8 migraine risk factors.ResultsAfter correcting for multiple testing, we found evidence for associations of genetically predicted coffee, cheese, oily fish, alcohol (red wine), raw vegetables, muesli, and wholemeal/wholegrain bread intake with decreased risk of migraine, those odds ratios ranged from 0.78 (95% CI: 0.63–0.95) for overall cheese intake to 0.61 (95% CI: 0.47–0.80) for drinks usually with meals among current drinkers (yes + it varies vs. no); while white bread, cornflakes/frosties, and poultry intake were positively associated with the risk of migraine. Additionally, genetic liability to white bread, wholemeal/wholegrain bread, muesli, alcohol (red wine), cheese, and oily fish intake were associated with a higher risk of insomnia and (or) major depression disorder (MDD), each of them may act as a mediator in the pathway from several dietary habits to migraine. Finally, we found evidence of a negative association between genetically predicted migraine and drinking types, and positive association between migraine and cups of tea per day.SignificanceOur study provides evidence about association between dietary habits and the risk of migraine and demonstrates that some associations are partly mediated through one or both insomnia and MDD. These results provide new insights for further nutritional interventions for migraine prevention
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