On Myopic Sensing for Multi-Channel Opportunistic Access: Structure, Optimality, and Performance

We consider a multi-channel opportunistic communication system where the states of these channels evolve as independent and statistically identical Markov chains (the Gilbert-Elliot channel model). A user chooses one channel to sense and access in each slot and collects a reward determined by the state of the chosen channel. The problem is to design a sensing policy for channel selection to maximize the average reward, which can be formulated as a multi-arm restless bandit process. In this paper, we study the structure, optimality, and performance of the myopic sensing policy. We show that the myopic sensing policy has a simple robust structure that reduces channel selection to a round-robin procedure and obviates the need for knowing the channel transition probabilities. The optimality of this simple policy is established for the two-channel case and conjectured for the general case based on numerical results. The performance of the myopic sensing policy is analyzed, which, based on the optimality of myopic sensing, characterizes the maximum throughput of a multi-channel opportunistic communication system and its scaling behavior with respect to the number of channels. These results apply to cognitive radio networks, opportunistic transmission in fading environments, and resource-constrained jamming and anti-jamming.Comment: To appear in IEEE Transactions on Wireless Communications. This is a revised versio

Mining the Impact of Investor Sentiment on Stock Market from WeChat

In this study, the CSI 300 Index in China mainland and original articles from authoritative stock WeChat public accounts are investigated regarding their relations. First, a sentence-level sentiment classification approach for analyzing investor sentiment polarities in text corpus is proposed by expanding synonyms. Then, the Granger causality test is utilized to examine the impact of sentiment index on the stock price and volume-values. It shows that the influence of overall investor sentiment on volume-values is more rapid than that on stock price and the impact of positive sentiment is found to be more lasting than the negative in both stock price and volume-values. Furthermore, it is worth noting that there is a dual-stage phenomenon in the impact of positive sentiment on volume-values, which indicates that some investors react to positive information immediately while others may choose to wait and follow the trend

Molecular composition of GAG-collagen I multilayers affects remodeling of terminal layers and osteogenic differentiation of adipose-derived stem cells

The effect of molecular composition of multilayers, by pairing type I collagen (Col I) with either hyaluronic acid (HA) or chondroitin sulfate (CS) was studied regarding the osteogenic differentiation of adhering human adipose-derived stem cells (hADSCs). Polyelectrolyte multilayer (PEM) formation was based primarily on ion pairing and on additional intrinsic cross-linking through imine bond formation with Col I replacing native by oxidized HA (oHA) or CS (oCS). Significant amounts of Col I fibrils were found on both native and oxidized CS-based PEMs, resulting in higher water contact angles and surface potential under physiological condition, while much less organized Col I was detected in either HA-based multilayers, which were more hydrophilic and negatively charged. An important finding was that hADSCs remodeled Col I at the terminal layers of PEMs by mechanical reorganization and pericellular proteolytic degradation, being more pronounced on CS-based PEMs. This was in accordance with the higher quantity of Col I deposition in this system, accompanied by more cell spreading, focal adhesions (FA) formation and significant α2β1 integrin recruitment compared to HA-based PEMs. Both CS-based PEMs caused also an increased fibronectin (FN) secretion and cell growth. Furthermore, significant calcium phosphate deposition, enhanced ALP, Col I and Runx2 expression were observed in hADSCs on CS-based PEMs, particularly on oCS-containing one. Overall, multilayer composition can be used to direct cell-matrix interactions, and hence stem cell fates showing for the first time that PEMs made of biogenic polyelectrolytes undergo significant remodeling of terminal protein layers, which seems to enable cells to form a more adequate extracellular matrix-like environment. Statement of Significance: Natural polymer derived polyelectrolyte multilayers (PEMs) have been recently applied to adjust biomaterials to meet specific tissue demands. However, the effect of molecular composition of multilayers on both surface properties and cellular response, especially the fate of human adipose derived stem cells (hADSCs) upon osteogenic differentiation has not been studied extensively, yet. In addition, no studies exist that investigate a potential cell-dependent remodeling of PEMs made of extracellular matrix (ECM) components like collagens and glycosaminoglycans (GAGs). Furthermore, there is no knowledge whether the ability of cells to remodel PEM components may provide an added value regarding cell growth and differentiation. Finally, it has not been explored yet, how intrinsic cross-linking of ECM derived polyelectrolytes that improve the stability of PEMs will affect the differentiation potential of hADSCs. The current work aims to address these questions and found that the type of GAG has a strong effect on properties of multilayers and osteogenic differentiation of hADSCs. Additionally, we also show for the first time that PEMs made of biogenic polyelectrolytes undergo significant remodeling of terminal layers as completely new finding, which allows cells to form an ECM-like environment supporting differentiation upon osteogenic lineage. The finding of this work may open new avenues of application of PEM systems made by layer by layer (LbL) technique in tissue engineering and regenerative medicine

A Swarm-Based Rough Set Approach for Group Decision Support Systems

This paper present a class of investment problem, in which many items could be chosen in a group decision environment. Usually there is a decision table from the board of directors after discussions. Most of the data come from their experience or estimation. The information is redundant and inaccurate. Swarm-based rough set approach is introduced to make an attempt to solve the problem. Rough set theory provides a mathematical tool that can be used for both feature selection and information reduction. The swarm-based reduction approaches are attractive to find multiple reducts in the decision systems, which could be applied to generate multiple investment planning and to improve the decision. Empirical results illustrate that the approach can be applied for the class of investment problems effectively

Hydrogen Sulfide Attenuates Carbon Tetrachloride-Induced Hepatotoxicity, Liver Cirrhosis and Portal Hypertension in Rats

BACKGROUND : Hydrogen sulfide (H(2)S) displays vasodilative, anti-oxidative, anti-inflammatory and cytoprotective activities. Impaired production of H(2)S contributes to the increased intrahepatic resistance in cirrhotic livers. The study aimed to investigate the roles of H(2)S in carbon tetrachloride (CCl(4))-induced hepatotoxicity, cirrhosis and portal hypertension.METHODS AND FINDINGS : Sodium hydrosulfide (NaHS), a donor of H(2)S, and DL-propargylglycine (PAG), an irreversible inhibitor of cystathionine &gamma;-lyase (CSE), were applied to the rats to investigate the effects of H(2)S on CCl(4)-induced acute hepatotoxicity, cirrhosis and portal hypertension by measuring serum levels of H(2)S, hepatic H(2)S producing activity and CSE expression, liver function, activity of cytochrome P450 (CYP) 2E1, oxidative and inflammatory parameters, liver fibrosis and portal pressure. CCl(4) significantly reduced serum levels of H(2)S, hepatic H(2)S production and CSE expression. NaHS attenuated CCl(4)-induced acute hepatotoxicity by supplementing exogenous H(2)S, which displayed anti-oxidative activities and inhibited the CYP2E1 activity. NaHS protected liver function, attenuated liver fibrosis, inhibited inflammation, and reduced the portal pressure, evidenced by the alterations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), albumin, tumor necrosis factor (TNF)-&alpha;, interleukin (IL)-1&beta;, IL-6 and soluble intercellular adhesion molecule (ICAM)-1, liver histology, hepatic hydroxyproline content and &alpha;-smooth muscle actin (SMA) expression. PAG showed opposing effects to NaHS on most of the above parameters.CONCLUSIONS :&nbsp; Exogenous H2S attenuates CCl4-induced hepatotoxicity, liver cirrhosis and portal hypertension by its multiple functions including anti-oxidation, anti-inflammation, cytoprotection and anti-fibrosis, indicating that targeting H2S may present a promising approach, particularly for its prophylactic effects, against liver cirrhosis and portal hypertension.<br /

PREDICTION OF RACEWAYS IN A BLAST FURNACE

ABSTRACT In a blast furnace, preheated air and fuel (gas, oil or pulverized coal) are often injected into the lower part of the furnace through tuyeres, forming a raceway in which the injected fuel and some of the coke descending from the top of the furnace are combusted and gasified. The shape and size of the raceway greatly affect the combustion of the coke and the injected fuel in the blast furnace. In this paper, a three-dimensional (3-D) computational fluid dynamics (CFD) model is developed to investigate the raceway evolution. The furnace geometry and operating conditions are based on the Mittal Steel IH7 blast furnace. The effects of Tuyere velocity, coke particle size and burden properties are computed. It is found that the raceway depth increases with an increase in the tuyere velocity and a decrease in the coke particle size in the active coke zone. The CFD results are validated using experimental correlations and actual observations. The computational results provide useful insight into the raceway formation and the factors that influence its size and shape

Fabrication of Asymmetric Polysaccharide Composite Membranes as Guided Bone Regeneration Materials

Periodontal regeneration can be achieved by guided tissue and guided bone regeneration (GTR/GBR) membranes, which act as a physical barrier to exclude migration of connective and epithelium, favoring the repopulation of periodontal ligament cells. Asymmetric polysaccharide GBR membranes with two different surfaces were developed in this study. Positive chitosan (CS), negative hyluronaic acid (HA) and konjac glucomannan (KGM) were composited by electrostatic interaction, forming smooth and dense membranes as upper surface to inhibit the ingrowth of cells from gingiva. The lower porous and coarse surface was obtained by gel freeze-drying and mineralization to improve the regeneration of the bone tissue. The performance of the membranes was characterized by Infrared Radiation (IR), X-ray diffraction (XRD), scanning electron microscope (SEM), tensile strength and biological evaluation. It was found that the composite membranes with chitosan content of 56.7 wt%in the dry state possess the highest tensile strength, with elongation 10 times more higher than that of the pure CS ones. Additionaly, open pores with diameter of 10-100 µm and homogenouse distributed nano-hydroxyapatite (HAP) were investigated on the coarse part. Cell studies demonstrated that the porous surface promoted the growth of the preosteoblast. Overall, the composite membranes may be useful for regeneration of periodontal regeneration

Incremental value of non-invasive myocardial work for the evaluation and prediction of coronary microvascular dysfunction in angina with no obstructive coronary artery disease

BackgroundEvidence suggests that patients suffering from angina with no obstructive coronary artery disease (ANOCA) experience coronary microvascular dysfunction (CMD). We aimed to understand the diagnosis value of noninvasive myocardial work indices (MWIs) with left ventricular pressure-strain loop (LV PSL) by echocardiography in ANOCA patients with CMD.Methods97 patients with ANOCA were recruited. All subjects underwent standard echocardiography with traditional ultrasound parameters, two-dimensional speckle-tracking echocardiography with global longitudinal strain (GLS), LV PSL with MWIs include global work index (GWI), global constructive work (GCW), global waste work (GWW) and global work efficiency (GWE). In addition, all enrolled cases underwent high-dose adenosine stress echocardiography (SE) with coronary flow velocity reserve (CFVR). CMD was defined as CFVR &lt;2.0.ResultsOf the 97 patients with ANOCA, 52 were placed in the CMD group and 45 in the control group. GWI and GCW were decreased significantly in the CMD group compared with the control group (P &lt; 0.001 for both). GWI and GCW were moderately correlated with CFVR (r = 0.430, P &lt; 0.001 and r = 0.538, P &lt; 0.001, respectively). In the multiple logistic regression analyses, GCW was identified as the only independent echocardiography parameter associated with CMD after adjusting for age and baseline APV [OR (95%CI) 1.009 (1.005–1.013); P &lt; 0.001]. Moreover, the best predictor of CMD in patients with ANOCA using receiver operating characteristic (ROC) curve was GWI and GCW, with an area under the curve (AUC) of 0.800 and 0.832, sensitivity of 67.3% and 78.8%, specificity of 80.0% and 75.6%, respectively.ConclusionMWIs with LV PSL is a new method to detect LV systolic function noninvasively in ANOCA patients with CMD