Analyzing ranking data using decision tree

Ranking/preference data arises from many applications in marketing, psychology and politics. We establish a new decision tree model for the analysis of ranking data by adopting the concept of classification and regression tree [2]. We modify the existing splitting criteria, Gini and entropy, which can precisely measure the impurity of a set of ranking data. Two types of impurity measures for ranking data are introduced, namely n-wise and top-k measures. Minimal cost-complexity pruning is used to find the optimum-sized tree. In model assessment, the area under the ROC curve (AUC) is applied to evaluate the tree performance. The proposed methodology is implemented to analyze a partial ranking dataset of Inglehart's items collected in the 1993 International Social Science Programme survey. Change in importance of item values with country, age and level of education are identified.postprintThe European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML PKDD 2008), Antwerp, Belgium, 15-19 September 2008. In Proceedings of ECML PKDD 2008, p. 139-15

Spatially resolved MaNGA observations of the host galaxy of superluminous supernova 2017egm

Superluminous supernovae (SLSNe) are found predominantly in dwarf galaxies, indicating that their progenitors have a low metallicity. However, the most nearby SLSN to date, SN 2017egm, occurred in the spiral galaxy NGC 3191, which has a relatively high stellar mass and correspondingly high metallicity. In this paper, we present detailed analysis of the nearby environment of SN 2017egm using MaNGA IFU data, which provides spectral data on kiloparsec scales. From the velocity map we find no evidence that SN 2017egm occurred within some intervening satellite galaxy, and at the SN position most metallicity diagnostics yield a solar and above solar metallicity (12 + log (O/H) = 8.8-9.1). Additionally we measure a small H-alpha equivalent width (EW) at the SN position of just 34 Angs, which is one of the lowest EWs measured at any SLSN or Gamma-Ray Burst position, and indicative of the progenitor star being comparatively old. We also compare the observed properties of NGC 3191 with other SLSN host galaxies. The solar-metallicity environment at the position of SN 2017egm presents a challenge to our theoretical understanding, and our spatially resolved spectral analysis provides further constraints on the progenitors of SLSNe.Comment: Accepted version in ApJ Letter. Thank you for useful comment

Interactions between Amyloid-β and Hemoglobin: Implications for Amyloid Plaque Formation in Alzheimer's Disease

Accumulation of amyloid-β (Aβ) peptides in the brain is one of the central pathogenic events in Alzheimer's disease (AD). However, why and how Aβ aggregates within the brain of AD patients remains elusive. Previously, we demonstrated hemoglobin (Hb) binds to Aβ and co-localizes with the plaque and vascular amyloid deposits in post-mortem AD brains. In this study, we further characterize the interactions between Hb and Aβ in vitro and in vivo and report the following observations: 1) the binding of Hb to Aβ required iron-containing heme; 2) other heme-containing proteins, such as myoglobin and cytochrome C, also bound to Aβ; 3) hemin-induced cytotoxicity was reduced in neuroblastoma cells by low levels of Aβ; 4) Hb was detected in neurons and glial cells of post-mortem AD brains and was up-regulated in aging and APP/PS1 transgenic mice; 5) microinjection of human Hb into the dorsal hippocampi of the APP/PS1 transgenic mice induced the formation of an envelope-like structure composed of Aβ surrounding the Hb droplets. Our results reveal an enhanced endogenous expression of Hb in aging brain cells, probably serving as a compensatory mechanism against hypoxia. In addition, Aβ binds to Hb and other hemoproteins via the iron-containing heme moiety, thereby reducing Hb/heme/iron-induced cytotoxicity. As some of the brain Hb could be derived from the peripheral circulation due to a compromised blood-brain barrier frequently observed in aged and AD brains, our work also suggests the genesis of some plaques may be a consequence of sustained amyloid accretion at sites of vascular injury

The Antidiabetic Drug Lobeglitazone Protects Mice From Lipogenesis-Induced Liver Injury via Mechanistic Target of Rapamycin Complex 1 Inhibition

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder closely linked with type II diabetes (T2D). The progression of NAFLD is associated with the induction of lipogenesis through hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway. An increase in lipogenesis induces endoplasmic reticulum (ER) stress and accelerates oxidative liver injury in the pathogenesis of NAFLD. Lobeglitazone, one of thiazolidinediones (TZDs), is used as an antidiabetic drug to lower serum glucose level through an increase in insulin sensitivity. It is known to improve pathological symptoms in animals and humans with NAFLD. However, the underlying molecular mechanism of the protective effects of lobeglitazone against NAFLD has not been elucidated. Here, we show that under the physiological condition of acute lipogenesis, lobeglitazone inhibits hepatic lipid synthesis, the subsequent ER stress, and ω-oxidation of fatty acids by inhibiting the mTORC1 pathway. As a result, lobeglitazone protected mice from lipogenesis-induced oxidative liver injury. Taken together, lobeglitazone might be a suitable drug for the treatment of patients with diabetes and NAFLD

Comparative study on saponin fractions from Panax notoginseng inhibiting inflammation-induced endothelial adhesion molecule expression and monocyte adhesion

<p>Abstract</p> <p>Background</p> <p><it>Panax notoginseng </it>is commonly used for the treatment of cardiovascular diseases in China. The present study investigates the effects of three different saponin fractions (<it>ie </it>total saponins, PNS; protopanaxadiol-type saponin, PDS; and protopanaxatriol-type saponin, PTS) and two major individual ingredients (<it>ie </it>ginsenoside Rg₁and Rb₁) from <it>P. notoginseng </it>on the endothelial inflammatory response <it>in vitro </it>and <it>in vivo</it>.</p> <p>Methods</p> <p>Recombinant human tumor necrosis factor-α (TNF-α) was added to the culture medium of human coronary artery endothelial cells (HCAECs) to induce an inflammatory response. A cell adhesion assay was used to determine the effect of the <it>P. notoginseng </it>saponin fractions on endothelial-monocyte interaction. The cell adhesion molecule (CAMs) expression, including ICAM-1 and VCAM-1, in the protein level on the surface of endothelial cells were measured by cellular ELISA. CAMs expression in mRNA level was also assayed by qRT-PCR in the HCAECs and the aorta of rat fed with high cholesterol diet (HCD). Western blotting was used to detect effect of the saponin fractions on CAMs protein expression in HCAECs. In addition, nuclear translocation of p65, a surrogate marker for NF-κB activation, was measured by immunostaining.</p> <p>Results</p> <p>Three saponin fractions and two individual ginsenosides exhibited the inhibitory effects on monocyte adhesion on TNF-α-activated HCAECs and expression of ICAM-1 and VCAM-1 at both mRNA and protein levels <it>in vitro</it>. The saponin fractions exhibited a similar trend of the inhibitory effects on the mRNA expression of CAMs in the aorta of HCD-fed rat <it>in vivo</it>. These inhibitory effect of saponin fractions maybe attribute partially to the suppression of the TNF-α-induced NF-κB activation.</p> <p>Conclusion</p> <p>Our data demonstrate that saponin fractions (<it>ie </it>PNS, PDS and PTS) and major individual ginsenosides (<it>ie </it>Rg₁and Rb₁) have potential anti-atherogenic effects. Among the tested saponin fractions, PDS is the most potent saponin fraction against TNF-α-induced monocyte adhesion as well as the expression of adhesion molecules <it>in vitro </it>and <it>in vivo</it>.</p

Anticancer Effects of Salvia miltiorrhiza

Researchers have reported significant effects from Danshen (Salvia miltiorrhiza) in terms of inhibiting tumor cell proliferation and promoting apoptosis in breast cancer, hepatocellular carcinomas, promyelocytic leukemia, and clear cell ovary carcinomas. Here we report our data indicating that Danshen extracts, especially alcohol extract, significantly inhibited the proliferation of the human oral squamous carcinoma (OSCC) cell lines HSC-3 and OC-2. We also observed that Danshen alcohol extract activated the caspase-3 apoptosis executor by impeding members of the inhibitor of apoptosis (IAP) family, but not by regulating the Bcl-2-triggered mitochondrial pathway in OSCC cells. Our data also indicate that the extract exerted promising effects in vivo, with HSC-3 tumor xenograft growth being suppressed by 40% and 69% following treatment with Danshen alcohol extract at 50 and 100 mg/kg, respectively, for 34 days. Combined, our results indicate appreciable anticancer activity and significant potential for Danshen alcohol extract as a natural antioxidant and herbal human oral cancer chemopreventive drug