34 research outputs found

    Effects of ammonia substitution on explosion limits of methane

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    As a hydrogen-rich and carbon-free fuel, ammonia is regarded as a promising carrier and storage medium for clean energy. By mixing methane with ammonia, the emission of carbon dioxide is also significantly reduced, which is of great significance for reducing greenhouse gas emissions and protecting the environment. However, ignition studies of ammonia/methane mixtures are still limited. In this paper, by means of numerical simulation with detailed chemical reaction mechanism, the effect of ammonia replacing methane on combustion was analyzed. Characteristics of explosion limit under different temperature (750-850K), equivalent ratio (0.5, 1.0 and 2.0) and ammonia mixing ratio (0-90%) were studied. The results show that the explosion limit decreases with the increase of temperature and equivalence ratio. When the proportion of NH3 is around 10%, the explosion limit shows a turning point. When the mole fraction of NH3 is higher than 50%, the explosion limit shows obvious increasing tendency with ammonia addition. Moreover, sensitivity and rate of production were also analyzed to expand the understanding of explosion limit for premixed ammonia-methane fuel blends

    Two Oppositely Localised Frizzled RNAs as Axis Determinants in a Cnidarian Embryo

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    In phylogenetically diverse animals, including the basally diverging cnidarians, “determinants” localised within the egg are responsible for directing development of the embryonic body plan. Many such determinants are known to regulate the Wnt signalling pathway, leading to regionalised stabilisation of the transcriptional coregulator β-catenin; however, the only strong molecular candidate for a Wnt-activating determinant identified to date is the ligand Wnt11 in Xenopus. We have identified embryonic “oral–aboral” axis determinants in the cnidarian Clytia hemisphaerica in the form of RNAs encoding two Frizzled family Wnt receptors, localised at opposite poles of the egg. Morpholino-mediated inhibition of translation showed that CheFz1, localised at the animal pole, activates the canonical Wnt pathway, promotes oral fates including gastrulation, and may also mediate global polarity in the ectoderm. CheFz3, whose RNA is localised at the egg vegetal cortex, was found to oppose CheFz1 function and to define an aboral territory. Active downregulation mechanisms maintained the reciprocal localisation domains of the two RNAs during early development. Importantly, ectopic expression of either CheFz1 or CheFz3 was able to redirect axis development. These findings identify Frizzled RNAs as axis determinants in Clytia, and have implications for the evolution of embryonic patterning mechanisms, notably that diverse Wnt pathway regulators have been adopted to initiate asymmetric Wnt pathway activation

    PwHAP5, a CCAAT-binding transcription factor, interacts with PwFKBP12 and plays a role in pollen tube growth orientation in Picea wilsonii

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    The HAP complex occurs in many eukaryotic organisms and is involved in multiple physiological processes. Here it was found that in Picea wilsonii, HAP5 (PwHAP5), a putative CCAAT-binding transcription factor gene, is involved in pollen tube development and control of tube orientation. Quantitative real-time reverse transcription-PCR showed that PwHAP5 transcripts were expressed strongly in germinating pollen and could be induced by Ca2+. Overexpression of PwHAP5 in pollen altered pollen tube orientation, whereas the tube with PwHAP5RNAi showed normal growth without diminishing pollen tube growth. Furthermore, PwFKBP12, which encodes an FK506-binding protein (FKBP) was screened and a bimolecular fluorescence complementation assay performed to confirm the interaction of PwHAP5 and PwFKBP12 in vivo. Transient expression of PwFKBP12 in pollen showed normal pollen tube growth, whereas the tube with PwFKBP12RNAi bent. The phenotype of overexpression of HAP5 on pollen tube was restored by FKBP12. Altogether, our study supported the role of HAP5 in pollen tube development and orientation regulation and identified FKBP12 as a novel partner to interact with HAP5 involved in the process

    On the Reliability of Alternating Group Graph-Based Networks

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    The probability of having faults in a multiprocessor computer system increases as the size of system grows. One way to quantify the reliability of a system is using the probability that a fault-free subsystem of a certain size still exists with the presence of individual faults. The higher the probability is, the more reliable the system is. In this paper, we establish the reliability for networks based on AGn, the n-dimensional alternating group graph. More specifically, we calculate the probability of a subnetwork (or subgraph) AGn n−1 being fault-free, when given a single node\u27s fault probability. Since subnetworks of AGn intersect in highly complex manners, our scheme is to use the Principle of Inclusion–Exclusion to obtain a lower-bound of the probability, by considering intersections of up to four subgraphs. We show that the lower-bound derived this way is very close to the upper-bound obtained in a previous result, which means the lower-bound we get is a very tight one. Therefore, both lower-bound and upper-bound are close approximations of the accurate probability

    Minimum Neighborhood of Alternating Group Graphs

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    The minimum neighborhood and combinatorial property are two important indicators of fault tolerance of a multiprocessor system. Given a graph G , θ G (q) is the minimum number of vertices adjacent to a set of q vertices of G (1 ≤|V(G)| ). It is meant to determine θ G (q), the minimum neighborhood problem (MNP). In this paper, we obtain θ AGn (q) for an independent set with size q in an n -dimensional alternating group graph AG n , a well-known interconnection network for multiprocessor systems. We first propose some combinatorial properties of AG n . Then, we study the MNP for an independent set of two vertices and obtain that θ AGn (2)=4n-10. Next, we prove that θ AGn (3)=6n-16. Finally, we propose that θ AGn (4)=8n-24

    Strong Reliability of Star Graphs Interconnection Networks

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    Layered malicious nodes detection with graph attention network in human-cyber-physical networks

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    With the advancement of network information technology and smart device technology, cyberspace is gradually evolved into Human-Cyber-Physical Networks (HCPNs). At the same time, the security problems caused by malicious nodes are becoming more and more serious. It is urgent to propose an efficient approach for malicious node detection. In this paper, we apply graph attention network (GAT) to detect malicious nodes layer by layer in HCPN. In addition, we investigate the influence of graph structure features on the detection performance in terms of accuracy, precision, recall, F1-score by comparing with graph convolutional network-based approach. Experimental results show that our approach has better performance as well as stronger generalizability than graph convolutional network-based approach in general. © 2022 IEEE

    Factors Associated with the Uptake of Genetic Testing for Cancer Risks: A Pathway Analysis Using the Health Information National Trends Survey Data

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    Our study aimed to identify pathways from the source of information to the uptake of cancer genetic testing, with consideration of intermediate variables including perceptional, attitudinal and psychosocial factors. We used the Health Information National Trends Survey (2020 database) and constructed a structural equation model for pathway analysis (using SPSS version 24). Variables for socio-demographic, lifestyle and health information were also collected and used for confounding adjustment. A total of 2941 participants were analyzed (68.5%, non-Hispanic white; 59.7%, females; 58 years, median age; and 142 (4.8%) had undertaken genetic testing for cancer risk previously). Our pathway analysis found that only information from particular sources (i.e., healthcare providers and genetic counsellors) had positive and significant effects on people’s perceptions of cancer regarding its prevention, detection and treatment (standardized β range, 0.15–0.31, all p-values < 0.01). Following the paths, these perceptional variables (cancer prevention, detection and treatment) showed considerable positive impacts on the uptake of genetic testing (standardized β (95% CIs): 0.25 (0.20, 0.30), 0.28 (0.23, 0.33) and 0.12 (0.06, 0.17), respectively). Pathways involving attitudinal and psychosocial factors showed much smaller or insignificant effects on the uptake of genetic testing. Our study brings several novel perspectives to the behavior model and may underpin certain issues regarding cancer risk genetic testing
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