405 research outputs found
Variable Precision Rough Set Model for Incomplete Information Systems and Its Beta-Reducts
As the original rough set model is quite sensitive to noisy data, Ziarko proposed the variable precision rough set (VPRS) model to deal with noisy data and uncertain information. This model allowed for some degree of uncertainty and misclassification in the mining process. In this paper, the variable precision rough set model for an incomplete information system is proposed by combining the VPRS model and incomplete information system, and the beta-lower and beta-upper approximations are defined. Considering that classical VPRS model lacks a feasible method to determine the precision parameter beta when calculating the beta-reducts, we present an approach to determine the parameter beta. Then, by calculating discernibility matrix and discernibility functions based on beta-lower approximation, the beta-reducts and the generalized decision rules are obtained. Finally, a concrete example is given to explain the validity and practicability of beta-reducts which is proposed in this paper
Research on the Relationship Between the Logistics Service Quality and Customer Loyalty in C2C E-commerce
Progesterone Prevents Traumatic Brain Injury-Induced Intestinal Nuclear Factor kappa B Activation and Proinflammatory Cytokines Expression in Male Rats
We have previously shown that traumatic brain injury (TBI) can induce an upregulation of nuclear factor kappa B (NF-κB) and proinflammatory cytokines in the gut, which play an important role in the pathogenesis of acute gut mucosal injury mediated by inflammation. In this work, we investigated whether progesterone administration modulated intestinal NF-κB activity and proinflammatory cytokines expression after TBI in male rats. As a result, we found that administration of progesterone following TBI could decrease NF-κB binding activity, NF-κB p65 protein expression, and concentrations of interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in the gut. TBI-induced damages of gut structure were ameliorated after progesterone injections. The results of the present study suggest that the therapeutic benefit of post-TBI progesterone injections might be due to its inhibitory effects on intestinal NF-κB activation and proinflammatory cytokines expression
Combinatorial administration of insulin and vitamin C alleviates the cerebral vasospasm after experimental subarachnoid hemorrhage in rabbit
<p>Abstract</p> <p>Background</p> <p>Cerebral vasospasm (CVS) is a common serious complication after the spontaneous subarachnoid hemorrhage (SAH). Despite recent advances in medical and surgical treatments, the 30-day mortality rate of SAH remains high, and there is lack of especially effective clinical treatment to alleviate and improve CVS. The present study has investigated the therapeutic effect of insulin and vitamin C on CVS after SAH.</p> <p>Results</p> <p>Five days after SAH, there is obvious basilar artery spasm in SAH group, whose average vascular cross-sectional area (233,099 ± 16,750 μm<sup>2</sup>) is significantly smaller than that in control group (462,128 ± 74,756 μm<sup>2</sup>), which is also significantly different from those in SAH + insulin group (221,114 ± 43,457 μm<sup>2</sup>) and SAH + vitamin C group (237,820 ± 21,703 μm<sup>2</sup>). SAH + insulin + vitamin C group shows no evident vasospasm and maintains a vascular cross-sectional area of 425,530 ± 45,503 μm<sup>2</sup>, which is significantly different from that in SAH group. Insulin receptor α (InRα) expression is significantly downregulated in the vascular endothelial cells of SAH, SAH + insulin, and SAH + vitamin C groups (<it>P </it>< 0.01) but remains unchanged in vascular endothelial cells of SAH + insulin + vitamin C group (<it>P </it>> 0.05). Five days after SAH, serum and cerebrospinal fluid NO levels in SAH, SAH + insulin, and SAH + vitamin C groups decrease significantly (<it>P </it>< 0.01) compared to that in control group, whereas the reduction is not evident in SAH + insulin + vitamin C group (<it>P </it>> 0.05).</p> <p>Conclusion</p> <p>Combinatorial treatment with insulin and vitamin C has effectively relieved the CVS after SAH in rabbit, possibly through increasing the InRα expression and NO level, whereas treatment with insulin or vitamin C alone fails to do so.</p
Impact of bile acids on the growth of human cholangiocarcinoma via FXR
<p>Abstract</p> <p>Background</p> <p>The objective of the study was to investigate the effect of different types of bile acids on proliferation of cholangiocarcinoma and the potential molecular mechanisms.</p> <p>Methods</p> <p>PCR assay and Western blot were performed to detect the expression of farnesoid × receptor (FXR) in mRNA and protein level. Immunohistochemical analysis was carried out to monitor the expression of FXR in cholangiocarcinoma tissues from 26 patients and 10 normal controls. The effects on in vivo tumor growth were also studied in nude mouse model.</p> <p>Results</p> <p>Free bile acids induced an increased expression of FXR; on the contrary, the conjugated bile acids decreased the expression of FXR. The FXR effect has been illustrated with the use of the FXR agonist GW4064 and the FXR antagonist GS. More specifically, when the use of free bile acids combined with FXR agonist GW4064, the tumor cell inhibitory effect was even more pronounced. But adding FXR antagonist GS into the treatment attenuated the tumor inhibitory effect caused by free bile acids. Combined treatment of GS and CDCA could reverse the regulating effect of CDCA on the expression of FXR. Administration of CDCA and GW 4064 resulted in a significant inhibition of tumor growth. The inhibitory effect in combination group (CDCA plus GW 4064) was even more pronounced. Again, the conjugated bile acid-GDCA promoted the growth of tumor. We also found that FXR agonist GW4064 effectively blocked the stimulatory effect of GDCA on tumor growth. And the characteristic and difference of FXR expressions were in agreement with previous experimental results in mouse cholangiocarcinoma tissues. There was also significant difference in FXR expression between normal and tumor tissues from patients with cholangiocarcinoma.</p> <p>Conclusions</p> <p>The imbalance of ratio of free and conjugated bile acids may play an important role in tumorigenesis of cholangiocarcinoma. FXR, a member of the nuclear receptor superfamily, may mediate the effects induced by the bile acids.</p
Progress of Chinese research in physical oceanography of the Southern Ocean
Oceanographic surveying has been one of the key missions of the Chinese National Antarctic Research Expedition since 1984. Using the field data obtained in these surveys and the results from remote sensing and numerical models, Chinese physical oceanographers have investigated the water masses, fronts and circulation patterns in the Southern Ocean. The results of nearly 30 years of research are summarized in this paper. Most oceanographic observations by Chinese researchers have been conducted in Prydz Bay and the adjacent seas. CTD (Conductivity Temperature and Depth) data, collected during the past 20 years, have been applied to study several features of the water masses in this region: The spatial variation of warm summer surface water, the northward extension of shelf water, the flow of ice shelf water from the cavity beneath the Amery Ice Shelf, the upwelling of the Circumpolar Deep Water, and the formation of the Antarctic Bottom Water. The circulation and its dynamic factors have been analyzed with dynamic heights calculated from CTD data as well as by numerical models. The structure and strength of the fronts in the southeast Indian Ocean and the Drake Passage were investigated with underway XBT/XCTD (Expendable Bathythermograph/ Expendable CTD) and ADCP (Acoustic Doppler Current Profiler) data. Their interannual variations have been determined and the factors of influence, especially the atmospheric forcing and mesoscale oceanic processes, were studied using remote sensing data. The dynamic mechanism of the Antarctic Circumpolar Current (ACC) was analyzed by theoretical models. The transport and pattern of the ACC have been well reproduced by coupled sea ice-ocean models. Additional details of ACC variability were identified based on satellite altimeter data. The response of the ACC to climate change was studied using reanalysis data. Prospects for future research are presented at the end of this paper
Interfacial Properties of Monolayer and Bilayer MoS2 Contacts with Metals: Beyond the Energy Band Calculations
Although many prototype devices based on two-dimensional (2D) MoS2 have been
fabricated and wafer scale growth of 2D MoS2 has been realized, the fundamental
nature of 2D MoS2-metal contacts has not been well understood yet. We provide a
comprehensive ab initio study of the interfacial properties of a series of
monolayer (ML) and bilayer (BL) MoS2-metal contacts (metal = Sc, Ti, Ag, Pt,
Ni, and Au). A comparison between the calculated and observed Schottky barrier
heights (SBHs) suggests that many-electron effects are strongly suppressed in
channel 2D MoS2 due to a charge transfer. The extensively adopted energy band
calculation scheme fails to reproduce the observed SBHs in 2D MoS2-Sc
interface. By contrast, an ab initio quantum transport device simulation better
reproduces the observed SBH in the two types of contacts and highlights the
importance of a higher level theoretical approach beyond the energy band
calculation in the interface study. BL MoS2-metal contacts have a reduced SBH
than ML MoS2-metal contacts due to the interlayer coupling and thus have a
higher electron injection efficiency.Comment: 36 pages, 13 figures, 3 table
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