56 research outputs found
Inclusive production in B decays and the Enhancement due to charged technipions
The new contributions to the charmless B decay
from the unit-charged technipions and are estimated.
The technipions can provide a large enhancement to the inclusive branching
ratio: for
and when the effect of QCD gluon anomaly is also
taken into account. The new physics effect is essential to interpret the CLEO
data.Comment: Latex file, 7 pages with two EPS figure
Probabilistic Memory Model for Visual Images Categorization
During the past decades, numerous memory models have been proposed, which focused mainly on how spoken words are studied, whereas models on how visual images are studied are still limited. In this study, we propose a probabilistic memory model (PMM) for visual images categorization which is able to mimic the workings of the human brain during the image storage and retrieval. First, in the learning phase, the visual images are represented by the feature vectors extracted with convolutional neural network (CNN) and each feature component is assumed to conform to a Gaussian distribution and may be incompletely copied with a certain probability or randomly produced in accordance to an exponential distribution. Then, in the test phase, the likelihood ratio between the test image and each studied image is calculated based on the probabilistic inference theory, and an odd value in favor of an old item over a new one is obtained based on all likelihood values. Finally, if the odd value is above a certain threshold, the Bayesian decision rule is applied for image classification. Experimental results on two benchmark image datasets demonstrate that the proposed PMM can perform well on categorization tasks for both studied and non-studied images
decay in a Top quark two-Higgs-doublet model
We calculate the new physics contributions to the rare semileptonic decay induced by the charged-Higgs loop diagrams
appeared in the top quark two-Higgs doublet model (T2HDM). Within the
considered parameter space, we found that (a) the effective Wilson coefficients
( and ) in the T2HDM are
always standard model like; (b) the new physics contributions to
and can be
significant, but they tend to cancel each other; and (c) the T2HDM predictions
for agree well with the measured value within one
standard deviation.Comment: 18 pages, 8 eps figures, typos removed, final version appeared in PR
A Review: Meridianins and Meridianins Derivatives
Meridianins are a family of indole alkaloids derived from Antarctic tunicates with extensive pharmacological activities. A series of meridianin derivatives had been synthesized by drug researchers. This article reviews the extraction and purification methods, biological activities and pharmacological applications, pharmacokinetic characters and chemical synthesis of meridianins and their derivatives. And prospects on discovering new bioactivities of meridianins and optimizing their structure for the improvement of the ADMET properties are provided
Convenient Synthesis and Biological Evaluation of Bis(indolyl)methane Alkaloid and Bis(aryl)alkanes Derivatives with Anti-cancer Properties
An efficient and metal free methodology for the synthesis of bis(indolyl)methanes (BIMs) and bis(aryl)alkanes derivatives in the presence of B(C6F5)3 by the condensation of primary amines with pyruvates with good to high yields have been successfully developed. Some BIMs derivatives displayed good in vitro antitumor activity, screened by MTT assay. Compound 3b show the best anti-cancer activity against lung carcinoma cell A549 cells with IC50 of 4.52 µM.</jats:p
Metabolite Profiling of Meridianin C In Vivo of Rat by UHPLC/Q-TOF MS
Meridianin C (MC), as a marine alkaloid, is a potent protein kinase inhibitor which exhibits good anticancer activity. However, the in vivo metabolism of MC has not been described to date. In this study, an ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF MS) method is employed to investigate the in vivo metabolites of MC in rats. Plasma, bile, urine, and feces are collected after a single oral dose of MC. Protein precipitation, solid phase extraction (SPE), and ultrasonic extraction methods are used to prepare samples. Based on the mass spectral fragmentation patterns, elution order, and retrieving literatures, a total of 13 metabolites of MC were detected and tentatively identified, utilizing MetaboLynx software. The metabolic pathways of MC in rats include N- or O-glucuronidation, O-sulfation, N-hydroxylation, dihydroxylation, and trihydroxylation. The relative content of the metabolites in each kinds of biological samples is also evaluated. This study will help to understand the in vivo properties of MC for the future usage
Metabolite Profiling of Meridianin C In Vivo of Rat by UHPLC/Q-TOF MS
Meridianin C (MC), as a marine alkaloid, is a potent protein kinase inhibitor which exhibits good anticancer activity. However, the in vivo metabolism of MC has not been described to date. In this study, an ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF MS) method is employed to investigate the in vivo metabolites of MC in rats. Plasma, bile, urine, and feces are collected after a single oral dose of MC. Protein precipitation, solid phase extraction (SPE), and ultrasonic extraction methods are used to prepare samples. Based on the mass spectral fragmentation patterns, elution order, and retrieving literatures, a total of 13 metabolites of MC were detected and tentatively identified, utilizing MetaboLynx software. The metabolic pathways of MC in rats include N- or O-glucuronidation, O-sulfation, N-hydroxylation, dihydroxylation, and trihydroxylation. The relative content of the metabolites in each kinds of biological samples is also evaluated. This study will help to understand the in vivo properties of MC for the future usage.</jats:p
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