92 research outputs found

    Ferromagnetism in exfoliated tungsten disulfide nanosheets

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    Summary of drug therapy to treat cognitive impairment-induced obstructive sleep apnea

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    Obstructive sleep apnea (OSA) is a severe sleep disorder associated with intermittent hypoxia and sleep fragmentation. Cognitive impairment is a signifi- cant and common OSA complication often described in such patients. The most commonly utilized methods in clinical OSA treatment are oral appliances and continuous positive airway pressure (CPAP). However, the current therapeutic methods for improving cognitive function could not achieve the expected efficacy in same patients. Therefore, further understanding the molecular mechanism behind cognitive dysfunction in OSA disease will provide new treatment methods and targets. This review briefly summarized the clinical manifestations of cognitive impairment in OSA disease. Moreover, the pathophysiological molecular mechanism of OSA was outlined. Our study concluded that both SF and IH could induce cognitive impairment by multiple signaling pathways, such as oxidative stress activation, inflammation, and apoptosis. However, there is a lack of effective drug therapy for cognitive impairment in OSA. Finally, the therapeutic potential of some novel compounds and herbal medicine was evaluated on attenuating cognitive impairment based on certain preclinical studies

    Effect of post-peak cyclic load on mechanics and seepage characteristics of sandstone under different confining pressures

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    The mining disturbance causes the rock mass in a certain range of the coal seam floor to be in a post-peak state. Due to the excavation of adjacent roadways and the mining of coal seams, the post-peak rock mass undergoes a cyclic loading-unloading process. In order to explore the influence of post-peak cyclic loading on rock mass structure under different in-situ stress environments and clarify the gestation process of disasters such as water inrush from coal seam floor, post-peak cyclic loading tests of sandstone under 5,10,15,20,25 MPa confining pressure were carried out based on Rock Top multi-field coupling tester. The results show that: ① Before the post-peak cyclic loading, the unit permeability of rock shows a rapid decline-tend to be stable-sudden rise-sudden decline-tend to be stable. In the post-peak cycle stage, the unit permeability of rock is almost inverted with the axial load. ② Rock elastic modulus, crack closure stress, crack initiation stress, damage stress, peak stress and residual stress are positively correlated with confining pressure, while Poisson 's ratio increases first and then decreases with the increase of confining pressure. ③ Under the confining pressure of 5 and 10 MPa, the intermittent failure of rock occurs, and the brittle failure characteristics are weakened. Under the confining pressure of 15, 20 and 25 MPa, the brittle failure characteristics of rock are obvious, and the failure characteristics of rock are determined by the properties of rock itself. ④ The post-peak axial load mainly promotes the increase of rock permeability, but the promotion effect is weaker than that of confining pressure on rock permeability, and confining pressure is the dominant factor affecting the post-peak permeability change of rock. ⑤ Under different confining pressures, a through-shear crack occurs in all rocks, but with the increase of confining pressure, the degree of rock failure gradually weakens and the failure mode tends to be simple

    Intelligent contour extraction approach for accurate segmentation of medical ultrasound images

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    Introduction: Accurate contour extraction in ultrasound images is of great interest for image-guided organ interventions and disease diagnosis. Nevertheless, it remains a problematic issue owing to the missing or ambiguous outline between organs (i.e., prostate and kidney) and surrounding tissues, the appearance of shadow artifacts, and the large variability in the shape of organs.Methods: To address these issues, we devised a method that includes four stages. In the first stage, the data sequence is acquired using an improved adaptive selection principal curve method, in which a limited number of radiologist defined data points are adopted as the prior. The second stage then uses an enhanced quantum evolution network to help acquire the optimal neural network. The third stage involves increasing the precision of the experimental outcomes after training the neural network, while using the data sequence as the input. In the final stage, the contour is smoothed using an explicable mathematical formula explained by the model parameters of the neural network.Results: Our experiments showed that our approach outperformed other current methods, including hybrid and Transformer-based deep-learning methods, achieving an average Dice similarity coefficient, Jaccard similarity coefficient, and accuracy of 95.7 ± 2.4%, 94.6 ± 2.6%, and 95.3 ± 2.6%, respectively.Discussion: This work develops an intelligent contour extraction approach on ultrasound images. Our approach obtained more satisfactory outcome compared with recent state-of-the-art approaches . The knowledge of precise boundaries of the organ is significant for the conservation of risk structures. Our developed approach has the potential to enhance disease diagnosis and therapeutic outcomes

    Synthesis, Magnetic Anisotropy and Optical Properties of Preferred Oriented Zinc Ferrite Nanowire Arrays

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    Preferred oriented ZnFe2O4 nanowire arrays with an average diameter of 16 nm were fabricated by post-annealing of ZnFe2 nanowires within anodic aluminum oxide templates in atmosphere. Selected area electron diffraction and X-ray diffraction exhibit that the nanowires are in cubic spinel-type structure with a [110] preferred crystallite orientation. Magnetic measurement indicates that the as-prepared ZnFe2O4 nanowire arrays reveal uniaxial magnetic anisotropy, and the easy magnetization direction is parallel to the axis of nanowire. The optical properties show the ZnFe2O4 nanowire arrays give out 370–520 nm blue-violet light, and their UV absorption edge is around 700 nm. The estimated values of direct and indirect band gaps for the nanowires are 2.23 and 1.73 eV, respectively

    Regulatory Feedback Loop of Two phz Gene Clusters through 5′-Untranslated Regions in Pseudomonas sp. M18

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    BACKGROUND: Phenazines are important compounds produced by pseudomonads and other bacteria. Two phz gene clusters called phzA1-G1 and phzA2-G2, respectively, were found in the genome of Pseudomonas sp. M18, an effective biocontrol agent, which is highly homologous to the opportunistic human pathogen P. aeruginosa PAO1, however little is known about the correlation between the expressions of two phz gene clusters. METHODOLOGY/PRINCIPAL FINDINGS: Two chromosomal insertion inactivated mutants for the two gene clusters were constructed respectively and the correlation between the expressions of two phz gene clusters was investigated in strain M18. Phenazine-1-carboxylic acid (PCA) molecules produced from phzA2-G2 gene cluster are able to auto-regulate expression itself and activate the expression of phzA1-G1 gene cluster in a circulated amplification pattern. However, the post-transcriptional expression of phzA1-G1 transcript was blocked principally through 5'-untranslated region (UTR). In contrast, the phzA2-G2 gene cluster was transcribed to a lesser extent and translated efficiently and was negatively regulated by the GacA signal transduction pathway, mainly at a post-transcriptional level. CONCLUSIONS/SIGNIFICANCE: A single molecule, PCA, produced in different quantities by the two phz gene clusters acted as the functional mediator and the two phz gene clusters developed a specific regulatory mechanism which acts through 5'-UTR to transfer a single, but complex bacterial signaling event in Pseudomonas sp. strain M18

    LIQUEFACTION OF CORN DISTILLERS DRIED GRAINS WITH SOLUBLES (DDGS) IN HOT-COMPRESSED PHENOL

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    The present work aims to liquefy corn Distillers Dried Grains with Solubles (DDGS), a by-product in corn ethanol production, to produce liquid products as a potential substitute for petroleum-derived phenol or an additive in the manufacturing of phenolic resins. Efficient liquefaction of DDGS has been realized with hot-compressed phenol at 200-450oC. Effects of liquefaction temperature, initial phenol/DDGS ratio, residence time and catalysts on yields of liquefaction products, as well as characterizations of typical liquid and solid products, have been investigated. The yield of liquid products increased with temperature, while it peaked at around 300oC, due to condensation/cracking reactions of the liquid intermediates/products to form solid products (i.e., coke/char) at temperatures higher than 300oC. The liquid yield increased monotonically with the initial phenol/DDGS ratio for a specified treatment time and temperature. An increased residence time generally produced a lower yield of liquid products, and a higher yield of solid residue, which was likely due to the increased coke/char formation from liquid products for a prolonged residence time. The yield of liquid products reached a maximum of 97% at 300oC for 5 min-operation with Phenol/DDGS of 2/1. K2CO3, Rb2CO3 and NaOH were found very effective catalysts for enhancing the liquid yields. The use of these catalysts resulted in 25% increase in the liquid yields for 5 min-operation with Phenol/DDGS of 1/1 at 300oC

    Endoplasmic Reticulum Stress-Mediated Hippocampal Neuron Apoptosis Involved in Diabetic Cognitive Impairment

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    Poor management of DM causes cognitive impairment while the mechanism is still unconfirmed. The aim of the present study was to investigate the activation of C/EBP Homology Protein (CHOP), the prominent mediator of the endoplasmic reticulum (ER) stress-induced apoptosis under hyperglycemia. We employed streptozotocin- (STZ-) induced diabetic rats to explore the ability of learning and memory by the Morris water maze test. The ultrastructure of hippocampus in diabetic rats and cultured neurons in high glucose medium were observed by transmission electron microscopy and scanning electron microscopy. TUNEL staining was also performed to assess apoptotic cells while the expression of CHOP was assayed by immunohistochemistry and Western blot assay in these hippocampal neurons. Six weeks after diabetes induction, the escape latency increased and the average frequency in finding the platform decreased in diabetic rats (P<0.05). The morphology of neuron and synaptic structure was impaired; the number of TUNEL-positive cells and the expression of CHOP in hippocampus of diabetic rats and high glucose medium cultured neurons were markedly altered (P<0.05). The present results suggested that the CHOP-dependent endoplasmic reticulum (ER) stress-mediated apoptosis may be involved in hyperglycemia-induced hippocampal synapses and neurons impairment and promote the diabetic cognitive impairment

    Catalytic Performance of Several Metallic Oxides on The Elimination Reactions of NO

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    Catalytic performance of several metallic oxides, i.e., AI,03, Cu,O, CuO, Cr,03, Fe,o" MnO" Ni,03 and V,05, and some of their partially-reduced samples to the elimination reaction of NO in NO-CO-C02-N2 and NO-N2 systems were examined using a flow-type reactor. The catalytic mechanism in the present condition was also discussed.The experimental results show that most of the metallic oxide samples give a catalytic effect on NO/CO reaction with different extent. Fe203, CuO, Ni,03 and Cr,oa show large catalytic activities, while those of Cu,O, MnO, and AI,03 are quite small. Further, it was found that the pre-reduced Ni20 3 sample also showed remarkable catalytic activity for direct decomposition of NO
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