14,566 research outputs found

    Dispelling the Anthropic Principle from the Dimensionality Arguments

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    It is shown that in d=11 supergravity, under a very reasonable ansatz, the nearly flat spacetime in which we are living must be 4-dimensional without appealing to the Anthropic Principle. Can we dispel the Anthropic Principle completely from cosmology?Comment: 7 pages, Essa

    B ->\eta_c K(\eta_c^\prime K) decays in QCD factorization

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    We study the exclusive decays of BB meson into pseudoscalar charmonium states ηc\eta_c and ηc\eta_c^\prime within the QCD factorization approach and find that the nonfactorizable corrections to naive factorization are infrared safe at leading-twist order. The spectator interactions arising from the kaon twist-3 effects are formally power-suppressed but chirally and logarithmically enhanced. The theoretical decay rates are too small to accommodate the experimental data. On the other hand, we compare the theoretical calculations for J/ψ,ψJ/\psi, \psi^\prime, and ηc,ηc\eta_c, \eta_c^\prime, and find that the predicted relative decay rates of these four states are approximately compatible with experimental data.Comment: 8 pages, LaTex, 1 figure, one footnote and two references adde

    Optimization-Based Peptide Mass Fingerprinting for Protein Mixture Identification

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    *Motivation:* In current proteome research, peptide sequencing is probably the most widely used method for protein mixture identification. However, this peptide-centric method has its own disadvantages such as the immense volume of tandem Mass Spectrometry (MS) data for sequencing peptides. With the fast development of technology, it is possible to investigate other alternative techniques. Peptide Mass Fingerprinting (PMF) has been widely used to identify single purified proteins for more than 15 years. Unfortunately, this technique is less accurate than peptide sequencing method and cannot handle protein mixtures, which hampers the widespread use of PMF technique. If we can remove these limitations, PMF will become a useful tool in protein mixture identification. 
*Results:* We first formulate the problem of PMF protein mixture identification as an optimization problem. Then, we show that the use of some simple heuristics enables us to find good solutions. As a result, we obtain much better identification results than previous methods. Moreover, the result on real MS data can be comparable with that of the peptide sequencing method. Through a comprehensive simulation study, we identify a set of limiting factors that hinder the performance of PMF method in protein mixtures. We argue that it is feasible to remove these limitations and PMF can be a powerful tool in the analysis of protein mixtures

    A study on the anticancer activity of ethanol extract of Aristolochia mollissima hance on osteosarcoma HOS cells

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    This paper mainly studied the extraction process of traditional Chinese medicine Aristolochia mollissima Hance (Aristolochiaceae) and the inhibitory effect of its extracts on osteosarcoma HOS cells. The extraction process included the ultrasonic extraction method, heat reflux method and decoction method to obtain three different extracts. MTT assay was used to test the effect of the extracts on proliferation of HOS cells, to compare the degree of inhibitory activity of three extracts, and to calculate cell survival rates. The results showed that among the three extracts obtained by the ultrasonic extraction method, heat reflux method and decoction method, the one obtained by ultrasonic extraction has the largest yield, but the extractobtained by heat reflux method has the strongest anticancer activity. Nevertheless, the three extracts all have a good inhibitory activity on theproliferation of osteosarcoma HOS cells.Key words: Aristolochia mollissima Hance; HOS cells; MTT; Anticance
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