553 research outputs found
Phytochemical Composition, Antioxidant Activity, and Neuroprotective Effect of Terminalia chebula Retzius Extracts
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
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
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
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
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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