107 research outputs found

    Birth places of extreme ultraviolet waves driven by impingement of solar jets upon coronal loops

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    Solar extreme ultraviolet (EUV) waves are large-scale propagating disturbances in the corona. It is generally believed that the vital key for the formation of EUV waves is the rapid expansion of the loops that overlie erupting cores in solar eruptions, such as coronal mass ejections (CMEs) and solar jets. However, the details of the interaction between the erupting cores and overlying loops are not clear, because that the overlying loops are always instantly opened after the energetic eruptions. Here, we present three typical jet-driven EUV waves without CME to study the interaction between the jets and the overlying loops that remained closed during the events. All three jets emanated from magnetic flux cancelation sites in source regions. Interestingly, after the interactions between jets and overlying loops, three EUV waves respectively formed ahead of the top, the near end (close to the jet source), and the far (another) end of the overlying loops. According to the magnetic field distribution of the loops extrapolated from Potential Field Source Surface method, it is confirmed that the birth places of three jet-driven EUV waves were around the weakest magnetic field strength part of the overlying loops. We suggest that the jet-driven EUV waves preferentially occur at the weakest part of the overlying loops, and the location can be subject to the magnetic field intensity around the ends of the loops

    Blade-Tip Vortex Noise Mitigation Traded-Off against Aerodynamic Design for Propellers of Future Electric Aircraft

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    We study noise generation at the blade tips of propellers designed for future electric aircraft propulsion and, furthermore, analyze the interrelationship between noise mitigation and aerodynamics improvement in terms of propeller geometric designs. Classical propellers with three or six blades and a conceptual propeller with three joined dual-blades are compared to understand the effects of blade tip vortices on the noise generation and aerodynamics. The dual blade of the conceptual propeller is constructed by joining the tips of two sub-blades. These propellers are designed to operate under the same freestream flow conditions and similar electric power consumption. The Improved Delayed Detached Eddy Simulation (IDDES) is adopted for the flow simulation to identify high-resolution time-dependent noise sources around the blade tips. The acoustic computations use a time-domain method based on the convective Ffowcs Williams–Hawkings (FW-H) equation. The thrust of the 3-blade conceptual propeller is\ua04%\ua0larger than the 3-blade classical propeller and\ua08%\ua0more than the 6-blade one, given that they have similar efficiencies. Blade tip vortices are found emitting broadband noise. Since the classical and conceptual 3-blade propellers have different geometries, especially at the blade tips, they introduce deviations in the vortex development. However, the differences are small regarding the broadband noise generation. As compared to the 6-blade classical propeller, both 3-blade propellers produce much larger noise. The reason is that the increased number of blades leads to the reduced strength of tip vortices. The findings indicate that the noise mitigation through the modification of the blade design and number can be traded-off by the changed aerodynamic performance

    Numbers of Publications Related to Laboratory Animals

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    Laboratory animals are widely utilized in biomedical research, so a search of scientific publications can  give us useful information on the use of animals. We retrieved the PubMed biomedicine database and  searched for publications related to laboratory animals from 1966 to 2005. We found that rats and mice  constitute the vast majority of species used in biomedical research; C57BL and BABL/c inbred mice, and  Sprague Dawley and Wistar outbred rats are the most common strains. Recently, the numbers of publications  relating to traditionally used animals such as rats, guinea pigs, dogs, cats, and sheep decreased slightly,  whereas the numbers relating to mice, fish, Drosophila and Caenorhabditis elegans increased from 1995  to 2005, with annual mean growth rates of 4.5%, 8.22%, 1.95%, and 10.3%, respectively. Publications  involving transgenic mice increased dramatically from the mid-1980s. This survey provides significant  clues for predicting the future direction of biomedical research.

    Reducing the aerodynamic drag of high-speed trains by air blowing from the nose part: Effect of blowing speed

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    To reduce the aerodynamic drag of high-speed trains, this work proposes an air blowing configuration on the head and tail cars of high-speed trains. The variation in the aerodynamic drag and slipstream velocity is analyzed under different blowing velocities, and the flow mechanism for train aerodynamic performance alteration is explained. The results show that under the blowing speeds of Ub = 0.05Ut, 0.10Ut, 0.15Ut, and 0.20Ut, where Ut is the train speed, the total drag coefficient (Cd) decreases by 5.81%, 10.78%, 13.70%, and 15.43% compared to the without-blowing case, respectively. However, with the increase in the blowing speed, the reduction trend of Cd tends to be smoother; namely, the decrement ratio compared to the previous blowing speed for the head car is 9.08%, 0.11%, 0.60%, and 1.14% for Ub = 0.05Ut, 0.10Ut, 0.15Ut, and 0.20Ut, respectively. The blowing measure generates an air gap between the coming flow and train surface, consequently causing a reduction in the viscous and pressure drag. In addition, the structure size and strength of the wake flow under different blowing cases show a decreasing trend from Ub = 0.00Ut to 0.10Ut and then an increasing trend from Ub = 0.10Ut to 0.20Ut. Thus, considering the blowing cost, efficiency, and flow structure evolution comprehensively, the case of Ub = 0.10Ut is recommended. Under this blowing speed, the reduction ratio of the aerodynamic drag is 9.18%, 12.77%, 10.90%, and 10.78% for the head, middle, tail car, and total train, respectively

    Use of Electroencephalography for the Study of Gain–Loss Asymmetry in Intertemporal Decision-Making

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    Intertemporal decision-making refers to the process whereby an individual evaluates and selects among competing alternatives based on the cost and benefit over time. While most previous studies on temporal discounting focused their attention on the gain context, only a few explored the loss context. In the present study, both the event-related potentials (ERPs) and the graph theory analysis were employed to investigate the differences in intertemporal decision-making between the gain and loss frameworks. Our results suggested that participants preferred the short latency/small amount (SS) alternatives and exhibited a smaller discount rate in a loss context compared to a gain framework. Furthermore, our ERP data indicated that the P200 component could constitute a preliminary assessment of the decision-making, related to gain and loss. In contrast, the N2 component was associated with negative emotions and showed significantly bigger amplitudes in the loss context, when compared to the gain framework. Further analyses of brain networks suggested the loss decision-making brain network to have a larger small-worldness index given individuals' loss aversion. Taken together, intertemploral decision-making in a loss context was accompanied by a greater brain response due to the negative emotions linked to loss aversion

    TRIB3, as a robust prognostic biomarker for HNSC, is associated with poor immune infiltration and cancer cell immune evasion

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    ObjectiveAs a pseudokinase, Tribbles Pseudokinase 3 (TRIB3) is implicated in a wide array of biological processes, including cell signal transduction, metabolic regulation, stress responses, and immune regulation. While its significant role in the immune regulation of certain cancers is well-established, the specific functions and impact of TRIB3 in head and neck squamous cell carcinoma (HNSC) remain unclear.MethodsThe data of RNA-sequence was acquired from the TCGA database to analyze the expression patterns of TRIB3 and elucidate its prognostic value in HNSC patients. Furthermore, the correlation between TRIB3 and tumor mutation burden, clinical data, immune checkpoint genes, and immune cell infiltration was explored. Moreover, the TRIB3 location in tumor tissues and subcellular structures was identified via Tisch in the HPA database, and the potential protein interaction molecules for TRIB3 were elucidated in the STRING database. The potential TRIB3 gene function was assessed using gene set enrichment analysis (GSEA), whereas the TRIB3 expression levels in clinical HNSC samples were verified by RT-qPCR and immunohistochemistry. the role of TRIB3 in enhancing the malignant behavior of HNSC cells was validated in vitro through a series of methods including RT-qPCR, CCK8 assay, wound healing assay, and transwell assay.ResultsIt was revealed that TRIB3 was significantly overexpressed in the nucleus and cytoplasm of HNSC. Furthermore, this overexpression markedly enhanced the migration ability of tumor cells. As an independent prognostic factor, TRIB3 was associated with advanced tumor T stage and was significantly involved with tumor mutation burden and immune cell infiltration in HNSC. Moreover, it was observed that TRIB3 was not a predicted factor for PD1/PDL1 and ATL4 inhibitor treatment; however, it was substantially correlated with various immune evasion-related genes in HNSC.ConclusionTRIB3 could serve as a potential prognostic marker for HNSC and might be a key gene mediating HNSC immune evasion

    Detection of neural connections with ex vivo MRI using a ferritin-encoding trans-synaptic virus

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    The elucidation of neural networks is essential to understanding the mechanisms of brain functions and brain disorders. Neurotropic virus-based trans-synaptic tracing tools have become an effective method for dissecting the structure and analyzing the function of neural-circuitry. However, these tracing systems rely on fluorescent signals, making it hard to visualize the panorama of the labeled networks in mammalian brain in vivo. One MRI method, Diffusion Tensor Imaging (DTI), is capable of imaging the networks of the whole brain in live animals but without information of anatomical connections through synapses. In this report, a chimeric gene coding for ferritin and enhanced green fluorescent protein (EGFP) was integrated into Vesicular stomatitis virus (VSV), a neurotropic virus that is able to spread anterogradely in synaptically connected networks. After the animal was injected with the recombinant VSV (rVSV), rVSV-Ferritin-EGFP, into the somatosensory cortex (SC) for four days, the labeled neural-network was visualized in the postmortem whole brain with a T2-weighted MRI sequence. The modified virus transmitted from SC to synaptically connected downstream regions. The results demonstrate that rVSV-Ferritin-EGFP could be used as a bimodal imaging vector for detecting synaptically connected neural-network with both ex vivo MRI and fluorescent imaging. The strategy in the current study has the potential to longitudinally monitor the global structure of a given neural-network in living animals

    Serum glucose, lactate dehydrogenase and hypertension are mediators of the 1 effect of body mass index on severity of COVID-19

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    Background: COVID-19 has a broad clinical specturm. We investigated the role of serum markers measured on admission on severity as assessed at discharge and investigated those which relate to the effect of BMI on severity. Methods: Clinical and laboratory data form 610 COVID-19 cases hospitalised in the province of Zheijang, China was investigated as risk factors for severe COVID-19 (assessed by respiratory distress) compared to mild or common forms using logistic regression methods. Biochemical markers were correlated with severity using spearman correlations and a ROC analysis was used to determine the individual contribution of each of the biochemical markers on severity. We carried out formal mediation analyses to investigate the extent of the effect of body mass index (BMI) on COVID-19 severity mediated by hypertension, glycemia, Lactose Dehydrogenase (LDH) at the time of hospitalisation and C-Reactive Protein levels (CRP), in units of standard deviations. Results: The individual markers measured on admission contributing most strongly to prediction of COVID-19 severity as assessed at discharge were LDH, CRP and glucose. The proportion of the effect of BMI on severity of COVID-19 mediated by CRP, glycemia or hypertension we find that glucose mediated 79% (

    Role of drugs used for chronic disease management on susceptibility and severity of COVID-19: A large case-control study

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    The study aimed to investigate whether specific medications used in the treatment chronic diseases affected either the development and/ or severity of COVID-19 in a cohort of 610 COVID-19 cases and 48,667 population-based controls from Zheijang, China. Using a cohort of 578 COVID-19 cases and 48,667 population-based controls from Zheijang, China we tested the role of usage of cardiovascular, antidiabetic and other medications on risk and severity of COVID 19. Analyses were adjusted for age, sex and BMI and for presence of relevant comorbidities. Individuals with hypertension taking calcium channel blockers had significantly increased risk [odds ratio (OR)= 1.73 (95% CI 1.2-2.3)] of manifesting symptoms of COVID-19 whereas those taking angiotensin receptor blockers and diuretics had significantly lower disease risk (OR=0.22; 95%CI 0.15-0.30 and OR=0.30; 95%CI 0.19-0.58 respectively). Among those with type 2 diabetes, dipeptidyl peptidase-4 inhibitors (OR= 6.02; 95% CI 2.3- 15.5) and insulin (OR= 2.71; 95% CI 1.6-5.5) were more and glucosidase inhibitors were less prevalent (OR= 0.11; 95% CI 0.1-0.3) among with COVID-19 patients. Drugs used in the treatment of hypertension and diabetes influence the risk of development of COVID-19, but, not its severity
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