553 research outputs found

    Phytochemical Composition, Antioxidant Activity, and Neuroprotective Effect of Terminalia chebula Retzius Extracts

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    The objectives of this study were to determine phytochemical compositions, chemiluminescence antioxidant activities, and neuroprotective effects on PC12 cells for water, methanol, and 95% ethanol extracts of the air-dried fruit of Terminalia chebula Retzius. The water extract afforded the greatest yield, and total phenolic and tannin content. The methanol extract yielded the greatest total triterpenoid content. Based on four chemiluminescence antioxidant assays, the three extracts showed various degrees of antioxidant activity. The methanol extract showed good antioxidant activity based on the horseradish peroxidase-luminol-hydrogen peroxide (H2O2) assay. The water extract appeared to have good antioxidant activities in cupric sulfate-Phen-Vc-H2O2 and luminol-H2O2 assays. Pyrogallol-luminol assay showed the 95% ethanol extract to have good antioxidant activity. The methanol and water extracts presented neuroprotective activities on H2O2-induced PC12 cell death at 0.5–5.0 μg/mL. Further investigations are necessary to verify these activities in vivo

    The Qing Imperial Academy of Medicine: Its Institutions and the Physicians Shaped by Them

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    This paper is intended to explain the changes in the activities of the Imperial Academy of Medicine during the Qing dynasty (1644-1911). By tracing its precedents and comparing their functions, I will explain its role during the Qing dynasty. Furthermore, the seemingly hidebound institutional codes in fact reveal interesting information about the dynamics of the Academy. Through examining the impacts of the regula-tions on personnel and their careers, we are able to explain the very different requirements of the Qing rulers for their medical service. Up until the Ming period (1368-1644) there was an institutional boundary between medical services for the palace and those for the state, even though they shared the same personnel. The Qing was the first dynasty in which even this unclear line disappeared. In this sense, the Qing Academy did not simply copy the tradition of its predecessors. Instead, the services for the emperor’s individual needs became more and more central to its mission. Thus, the common people’s rather critical perceptions of the bureau were largely true.In spite of its increased emphasis on serving the imperial household, the Qing Academy retained its connections with the government. As an alien regime, the Manchu court’s concern for the security of its rulers was much higher than during the previous dynasty. To meet the needs of the new regime, the device of the Qing Academy emphasized fostering elites rather than selecting them. Now the Academy not only provided medical educa-tion to the junior members as in earlier periods, but also shaped them in behavior. This affected both the organization of the Imperial Medical Academy, and the strategies of the physicians employed in it

    Play as You Like: Timbre-enhanced Multi-modal Music Style Transfer

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    Style transfer of polyphonic music recordings is a challenging task when considering the modeling of diverse, imaginative, and reasonable music pieces in the style different from their original one. To achieve this, learning stable multi-modal representations for both domain-variant (i.e., style) and domain-invariant (i.e., content) information of music in an unsupervised manner is critical. In this paper, we propose an unsupervised music style transfer method without the need for parallel data. Besides, to characterize the multi-modal distribution of music pieces, we employ the Multi-modal Unsupervised Image-to-Image Translation (MUNIT) framework in the proposed system. This allows one to generate diverse outputs from the learned latent distributions representing contents and styles. Moreover, to better capture the granularity of sound, such as the perceptual dimensions of timbre and the nuance in instrument-specific performance, cognitively plausible features including mel-frequency cepstral coefficients (MFCC), spectral difference, and spectral envelope, are combined with the widely-used mel-spectrogram into a timber-enhanced multi-channel input representation. The Relativistic average Generative Adversarial Networks (RaGAN) is also utilized to achieve fast convergence and high stability. We conduct experiments on bilateral style transfer tasks among three different genres, namely piano solo, guitar solo, and string quartet. Results demonstrate the advantages of the proposed method in music style transfer with improved sound quality and in allowing users to manipulate the output

    Increased ATP generation in the host cell is required for efficient vaccinia virus production

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    To search for cellular genes up-regulated by vaccinia virus (VV) infection, differential display-reverse transcription-polymerase chain reaction (ddRT-PCR) assays were used to examine the expression of mRNAs from mock-infected and VV-infected HeLa cells. Two mitochondrial genes for proteins that are part of the electron transport chain that generates ATP, ND4 and CO II, were up-regulated after VV infection. Up-regulation of ND4 level by VV infection was confirmed by Western blotting analysis. Up-regulation of ND4 was reduced by the MAPK inhibitor, apigenin, which has been demonstrated elsewhere to inhibit VV replication. The induction of ND4 expression occurred after viral DNA replication since ara C, an inhibitor of poxviral DNA replication, could block this induction. ATP production was increased in the host cells after VV infection. Moreover, 4.5 μM oligomycin, an inhibitor of ATP production, reduced the ATP level 13 hr after virus infection to that of mock-infected cells and inhibited viral protein expression and virus production, suggesting that increased ATP production is required for efficient VV production. Our results further suggest that induction of ND4 expression is through a Bcl-2 independent pathway

    A Shallow Ritz Method for Elliptic Problems with Singular Sources

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    In this paper, a shallow Ritz-type neural network for solving elliptic equations with delta function singular sources on an interface is developed. There are three novel features in the present work; namely, (i) the delta function singularity is naturally removed, (ii) level set function is introduced as a feature input, (iii) it is completely shallow, comprising only one hidden layer. We first introduce the energy functional of the problem and then transform the contribution of singular sources to a regular surface integral along the interface. In such a way, the delta function singularity can be naturally removed without introducing a discrete one that is commonly used in traditional regularization methods, such as the well-known immersed boundary method. The original problem is then reformulated as a minimization problem. We propose a shallow Ritz-type neural network with one hidden layer to approximate the global minimizer of the energy functional. As a result, the network is trained by minimizing the loss function that is a discrete version of the energy. In addition, we include the level set function of the interface as a feature input of the network and find that it significantly improves the training efficiency and accuracy. We perform a series of numerical tests to show the accuracy of the present method and its capability for problems in irregular domains and higher dimensions
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