1,317 research outputs found

    Homogenized finite element analysis on effective elastoplastic mechanical behaviors of composite with imperfect interfaces

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    A three-dimensional (3D) representative volume element (RVE) model was developed for analyzing effective mechanical behavior of fiber-reinforced ceramic matrix composites with imperfect interfaces. In the model, the fiber is assumed to be perfectly elastic until its tensile strength, and the ceramic material is modeled by an elasto-plastic Drucker-Prager constitutive law. The RVE model is then used to study the elastic properties and the tensile strength of composites with imperfect interfaces and validated through experiments. The imperfect interfaces between the fiber and the matrix are taken into account by introducing some cohesive contact surfaces. The influences of the interface on the elastic constants and the tensile strengths are examined through these interface models

    PINE: Universal Deep Embedding for Graph Nodes via Partial Permutation Invariant Set Functions

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    Graph node embedding aims at learning a vector representation for all nodes given a graph. It is a central problem in many machine learning tasks (e.g., node classification, recommendation, community detection). The key problem in graph node embedding lies in how to define the dependence to neighbors. Existing approaches specify (either explicitly or implicitly) certain dependencies on neighbors, which may lead to loss of subtle but important structural information within the graph and other dependencies among neighbors. This intrigues us to ask the question: can we design a model to give the maximal flexibility of dependencies to each node's neighborhood. In this paper, we propose a novel graph node embedding (named PINE) via a novel notion of partial permutation invariant set function, to capture any possible dependence. Our method 1) can learn an arbitrary form of the representation function from the neighborhood, withour losing any potential dependence structures, and 2) is applicable to both homogeneous and heterogeneous graph embedding, the latter of which is challenged by the diversity of node types. Furthermore, we provide theoretical guarantee for the representation capability of our method for general homogeneous and heterogeneous graphs. Empirical evaluation results on benchmark data sets show that our proposed PINE method outperforms the state-of-the-art approaches on producing node vectors for various learning tasks of both homogeneous and heterogeneous graphs.Comment: 24 pages, 4 figures, 3 tables. arXiv admin note: text overlap with arXiv:1805.1118

    Methyl 4-anilino-3-nitro­benzoate

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    In the mol­ecule of the title compound, C14H12N2O4, the aromatic rings are oriented at a dihedral angle of 51.50 (4)°. An intra­molecular N—H⋯O inter­action results in the formation of a six-membered ring having an envelope conformation. In the crystal structure, inter­molecular N—H⋯O inter­actions link the mol­ecules into centrosymmetric dimers. π–π contacts between the benzene rings [centroid–centroid distance = 3.708 (1) Å] may further stabilize the structure

    Changes and Relationship of PAF and TNF in Rats with Myocardial Ischaemia and Reperfusion Injury

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    In this study it is reported that: (1) the levels of blood platelet-activating factor and serum tumour necrosis factor significantly increased after coronary ligation and reperfusion, compared with sham-ligated controls, in an anaesthetized rat model; (2) compared with vehicle controls, pretreatment with the PAF antagonist BN 50739 (10 mg/kg, i.v.) produced significant decreases in infarct size (from 29.6 ± 4.0% to 22.4 ± 2.1%, p < 0.05 after 3 h ligation, and from 28.5 ± 9.5% to 10.5 ± 4.5%, p < 0.01 after 4 h reperfusion) and the level of serum TNF (from 10.4 ± 7.7 U/ml to 3.9 ± 4.8 U/ml, p < 0.05); and (3) a significan positive correlation was found between the level of blood PAF or serum TNF and infarct size. The present results indicate that PAF and TNF may be important mediators involved in myocardial ischaemia and reperfusion injury, and that PAF antagonists may exert a protective effect on ischaemic or reperfused myocardium by inhibiting the interaction of PAF and TNF

    Negative regulation of transcription coactivator p300 by orphan receptor TR3

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    p300 regulates the transcriptional activity of a variety of transcription factors by forming an activation complex and/or promoting histone acetylation. Here, we show a unique characteristic of orphan receptor TR3 in negatively regulating the function of p300. TR3 was found to interact with p300 and inhibited the acetylation of transcription factors induced by p300, resulting in the repression of their transcriptional activity. Further analysis revealed that both a conserved transcriptional adapter motif (TRAM) in p300 and a specific sequence FLELFIL in TR3 were critical for their interaction. TR3 binding completely covered the histone acetyltransferase (HAT) domain of p300 and resulted in suppression of the HAT activity, as the p300-induced histone H3 acetylation and transcription were inhibited with the presence TR3. Furthermore, an agonist of TR3, a natural octaketide isolated from Dothiorella sp. HTF3 of an endophytical fungus, was shown to be a potent compound for inhibiting p300 HAT activity (IC50=1.5 mu g/ml) in vivo. More importantly, this agonist could repress the transcriptional activity of transcription factors, and proliferation of cancer cells. Taken together, our results not only delineate a novel transcriptional repressor function for TR3, but also reveal its modulation on p300 HAT activity as the underlying mechanism

    Comparison of clinical outcomes of Ibutilide-guided cardioversion and direct current synchronized cardioversion after radiofrequency ablation of persistent atrial fibrillation

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    BackgroupIbutilide has already been used for cardioversion of persistent atrial fibrillation (PsAF) after radiofrequency catheter ablation (RFCA). The purpose of this study was to determine the effect of Ibutilide-guided cardioversion on clinical outcomes after individualized ablation of PsAF.MethodsFrom October 2020 to September 2021, consecutive patients with PsAF accepted for RFCA were prospectively enrolled. After individualized ablation including pulmonary vein isolation plus left atrial roof line ablation and personalized linear ablation based on left atrial low-voltage zones, patients were divided into the spontaneous conversion (SCV) group, direct current synchronized cardioversion (DCC) group and Ibutilide group according to different cardioversion types during ablation. The rates of freedom from atrial tachyarrhythmia (ATT) among the three groups were evaluated after follow-up.ResultsIn this study, 110 patients were enrolled, including 12 patients with SCV, 50 patients receiving DCC and 48 patients receiving Ibutilide cardioversion after individualized ablation. Among the three groups, the SCV group had shorter AF duration {12 months [interquartile range (IQR) 12–16], P = 0.042} and smaller left atrial diameter (LAD) [35 mm (IQR: 33–42), P = 0.023]. A 12-month freedom from ATT rate was 83.3% in SCV group, 69.4% in DCC group, and 79.2% in Ibutilide group, respectively (Log-rank, P = 0.745). During the follow-up [17 months (IQR: 15–19)], the rate of freedom from ATT of SCV group (83.3%), and Ibutilide group (72.9%) were both higher than that of DCC group (53.1%, P = 0.042). Moreover, Kaplan–Meier analysis showed a significantly higher sinus rhythm (SR) maintenance in Ibutilide group than in DCC group (Log-rank, P = 0.041). After adjusting for risk factors of AF recurrence, the hazard ratio for AF recurrence of the DCC group with reference to the Ibutilide group was 4.10 [95% confidence interval (CI) (1.87–8.98), P &lt; 0.001]. Furthermore, subgroup analysis showed that freedom from ATT rate in effective Ibutilide subgroup was significantly higher than noneffective Ibutilide subgroup (Log-rank, P &lt; 0.001).ConclusionFor the treatment of the patients with PsAF, Ibutilide-guided cardioversion after individualized RFCA may be benefit for maintenance of SR compared to conventional DCC, especially for the patients who are effective for administration of Ibutilide

    Long-term survival with a combination of immunotherapy, anti-angiogenesis, and traditional radiotherapy in brain metastatic small cell lung cancer: a case report

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    PurposeBrain metastases (BMs) are common in Small Cell Lung Cancer (SCLC), but the prognosis is very poor. Currently, there is no standard of care on what constitutes optimal treatment, and there is no consensus regarding maintenance therapy in SCLC.Case descriptionWe report the case of a 55-year-old man with advanced SCLC. After the initial diagnosis, he received routine chemotherapy and chest radiotherapy but developed brain metastases with 2 lesions seven months later. We used an effective combination therapy consisting of the antiangiogenic inhibitor, Anlotinib and whole-brain radiotherapy. We then administered anti-PD-L1 immunotherapy Atezolizumab in combination with Anlotinib as long-term maintenance therapy. Twelve months later, there was a progression in one of the brain metastases. The patient underwent further stereotactic radiotherapy (SRT) for the lesion. However, after four months of treatment with SRT, the lesion began to gradually grow in size. The patient underwent surgical resection of the lesion, which confirmed radioactive brain necrosis. After a full 3-year course of anti-PD-L1 therapy, the patient discontinued immunotherapy and was administered only Anlotinib as maintenance. At the time of writing up this report, the patient was alive and the overall survival reached 41 months after the onset of BM.ConclusionThis indicated a potential synergistic effect of combined immunotherapy and antiangiogenic targeted therapy with local radiotherapy in patients with BM-SCLC and can provide directions for future clinical decisions

    Long-term sky islands generate highly divergent lineages of a narrowly distributed stream salamander (Pachyhynobius shangchengensis) in mid-latitude mountains of East Asia

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    Background Climate oscillation may have a profound effect on species distributions, gene flow patterns and population demography. In response to environmental change, those species restricted to montane habitats experienced expansions and contractions along elevation gradients, which can drive differentiation among sky islands. Results The Shangcheng stout salamander (Pachyhynobius shangchengensis) is a cool stream amphibian restricted to high-elevation areas in the Dabie Mountains, East China. In the present study, we used mtDNA genes (Cyt b and ND2) of 193 individuals and 12 nuclear microsatellite loci genotyped on 370 individuals, representing 6 populations (JTX, KHJ, MW, TTZ, BYM and KJY) across the taxon’s distribution area, to investigate their genetic variation and evolutionary history of P. shangchengensis. Most populations showed unusually high levels of genetic diversity. Phylogenetic analyses revealed five monophyletic clades with divergence times ranging from 3.96 to 1.4 Mya. Accordingly, significant genetic differentiation was present between these populations. Bayesian skyline plot analyses provided that all populations underwent long-term population expansions since the last inter-glacial (0.13 Mya ~ 0.12 Mya). Msvar analyses found recent signals of population decline for two northern populations (JTX and KHJ) reflecting a strong bottleneck (approximately 15-fold decrease) during the mid-Holocene (about 6000 years ago). Ecological niche modelling has shown a discontinuity in suitable habitats for P. shangchengensis under different historical climatic conditions. Conclusions Our results suggest that the niche conservatism of P. shangchengensis and sky island effects may have led to long-term isolation between populations. In sky island refuges, the mid-latitude Dabie Mountains have provided a long-term stable environment for P. shangchengensis, which has led to the accumulation of genetic diversity and has promoted genetic divergence

    Nucleotide variation in ATHK1 region of Arabidopsis thaliana and its association study with drought tolerance

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    The ATHK1 gene in Arabidopsis encodes a putative histidine kinase that is transcriptionally upregulated in response to changes in external osmolarity. In this work, we investigated the nucleotide variability of the ATHK1 gene in a sample of 32 core Arabidopsis accessions originating from different ecoclimatic regions and their drought tolerance. The results showed that different accessions had quite difference in adaptation to drought stress. Thirty-two Arabidopsis accessions were clustered into four groups according to their drought tolerance capacity. Relative water content of the leaves (RWC) combined anyone of membrane permeability of leaves (MP) and water retain capacity of detached leaves (WRC) were selected as two representative physiological indexes for evaluation of comprehensive drought tolerance. Sequencing 5 515 bp encompassing ATHK1 coding region in 32 core accessions revealed 39 polymorphisms, which formed 24 haplotypes. The polymorphism (including single nucleotide polymorphism (SNP) and insertion/deletion (Indel)) frequency was 1 SNP per 131.2 bp. In coding region of ATHK1, the ratio of average number of nucleotide difference π n /π s ratio was 0.727, suggesting that the ATHK1 protein is not constrained against amino acid changes within the species and this gene belonged to the middle evolution rate gene. Using ANOVA analysis, it showed that the 1199 site amino acid (Ser stop) variation of the eleventh haplotype (257 and 266av) was associated with not only RWC but also WRC, indicating that the change of Ser stop is associated with comprehensive drought tolerance of 257 and 266av. This amino acid change may cause 257 and 266 av accessions originating from moist ecoclimatic region to be sensitive to dry climate, and likely be the evidence of adaptive evolution

    The Biology and Ecology of the Emerald Ash Borer, Agrilus planipennis, in China

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    The biology, ecology, and life cycle of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), were studied using regular inspection in the forest and observations in the laboratory. Results indicated that A. planipennis are mostly univoltine in Tianjin, China. They overwintered individually as mature larvae in shallow chambers excavated in the outer sapwood. In late July, some full-grown larvae began to build overwintering chambers, and all larvae entered the sapwood for dormancy by early November. A. planipennis pupated in the overwintering chamber from early April to mid May the following year, and the average pupal duration was about 20 days. In late April, some newly eclosed adults could be found in the pupal cells, but they had not yet emerged from the tree. Adults began to emerge in early May, with peak flight occurring in mid May. The average longevity of adults was about 21 days and the adult stage lasted through early July. The adults fed on ash foliage as a source of nutrition. Mating was usually conducted and completed on the leaf or trunk surfaces of ash trees. Oviposition began in mid May and eggs hatched on average in 15.7 days. The first instar larvae appeared in early June. The larval stage lasted about 300 days to complete an entire generation. The emerald ash borer had four larval instars on velvet ash, Fraxinus velutina (Scrophulariales: Oleaceae). The major natural control factors of A. planipennis were also investigated, and preliminary suggestions for its integrated management are proposed
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