1,517 research outputs found

    Hydroxymethyl furfural in chinese herbal medicines: Its formation, presence, metabolism, bioactivities and implications

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    Background: Chinese herbal medicines (CHMs) must be processed before being prescribed to patients. During the processing, some CHMs became brown and as such 5-hydroxymethyl furfural (HMF) generated. Increasing attention is being paid to the safety and effectiveness of HMF.Methods: This paper summarized previous and recent reports on HMF formation, its presence in CHMs, its metabolism and bioactivities, together with its implications for CHMs.Results: HMF had been detected in 41 CHMs, and increased by about 12~1200 times after heat processing in some CHMs. Current data showed that HMF has limited genotoxicity but various bioactivities, such as anti-oxidative, anti-apoptotic, anti-inflammatory, anti-hypoxic, anti-microbial, and inhibiting sickling of red blood cells.Conclusion: Accumulation of HMF during heat processing of CHMs indicates that Maillard reaction and caramelization occurred. The other products of the two browning reactions deserve more attention in the following investigations on heat processed CHM.Keywords: hydroxymethyl furfural, Chinese herbal medicine, Maillard reaction, caramelization

    Hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells

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    We study the hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells. The corresponding polariton states are given. The analytical solution and the numerical result of the stationary spectrum for the cavity field are finishedComment: 3 pages, 1 figure. appear in Communications in Theoretical Physic

    Influence of heavy modes on perturbations in multiple field inflation

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    We investigate linear cosmological perturbations in multiple field inflationary models where some of the directions are light while others are heavy (with respect to the Hubble parameter). By integrating out the massive degrees of freedom, we determine the multi-dimensional effective theory for the light degrees of freedom and give explicitly the propagation matrix that replaces the effective sound speed of the one-dimensional case. We then examine in detail the consequences of a sudden turn along the inflationary trajectory, in particular the possible breakdown of the low energy effective theory in case the heavy modes are excited. Resorting to a new basis in field space, instead of the usual adiabatic/entropic basis, we study the evolution of the perturbations during the turn. In particular, we compute the power spectrum and compare with the result obtained from the low energy effective theory.Comment: 24 pages, 13 figures; v2 substantial changes in sec.V; v3 matching the published version on JCA

    Shear viscosity, instability and the upper bound of the Gauss-Bonnet coupling constant

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    We compute the dimensionality dependence of η/s\eta/s for charged black branes with Gauss-Bonnet correction. We find that both causality and stability constrain the value of Gauss-Bonnet coupling constant to be bounded by 1/4 in the infinite dimensionality limit. We further show that higher dimensionality stabilize the gravitational perturbation. The stabilization of the perturbation in higher dimensional space-time is a straightforward consequence of the Gauss-Bonnet coupling constant bound.Comment: 16 pages,3 figures+3 tables,typos corrected, published versio

    Quantum size effects on the perpendicular upper critical field in ultra-thin lead films

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    We report the thickness-dependent (in terms of atomic layers) oscillation behavior of the perpendicular upper critical field Hc2⊥H_{c2\perp} in the ultra-thin lead films at the reduced temperature (t=T/Tct=T/T_c). Distinct oscillations of the normal-state resistivity as a function of film thickness have also been observed. Compared with the TcT_c oscillation, the Hc2⊥H_{c2\perp} shows a considerable large oscillation amplitude and a π\pi phase shift. The oscillatory mean free path caused by quantum size effect plays a role in Hc2⊥H_{c2\perp} oscillation.Comment: 4 pages, 4 figure

    Experimentally obtaining the Likeness of Two Unknown Quantum States on an NMR Quantum Information Processor

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    Recently quantum states discrimination has been frequently studied. In this paper we study them from the other way round, the likeness of two quantum states. The fidelity is used to describe the likeness of two quantum states. Then we presented a scheme to obtain the fidelity of two unknown qubits directly from the integral area of the spectra of the assistant qubit(spin) on an NMR Quantum Information Processor. Finally we demonstrated the scheme on a three-qubit quantum information processor. The experimental data are consistent with the theoretical expectation with an average error of 0.05, which confirms the scheme.Comment: 3 pages, 4 figure

    Coulomb-enhanced dynamic localization and Bell state generation in coupled quantum dots

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    We investigate the dynamics of two interacting electrons in coupled quantum dots driven by an AC field. We find that the two electrons can be trapped in one of the dots by the AC field, in spite of the strong Coulomb repulsion. In particular, we find that the interaction may enhance the localization effect. We also demonstrate the field excitation procedure to generate the maximally entangled Bell states. The generation time is determined by both analytic and numerical solutions of the time dependent Schrodinger equation.Comment: 12 pages, 5 figure

    Emerging and reemerging helminthiases and the public health of China.

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    Despite great strides in their control throughout the People's Republic of China, helminth infections remain an important public health problem. The Institute of Parasitic Diseases of the Chinese Academy of Preventive Medicine, under the guidance of the Chinese Ministry of Health, completed a nationwide survey of more than 1 million people that showed the high prevalence and intensity of intestinal nematode infections; prevalence can sometimes exceed 50% in the Yangtze River valley provinces. Schistosoma japonicum is also a major cause of illness in this region. Attempts to control Chinese helminthic diseases with conventional anthelminthic drugs have been partially thwarted by high posttreatment rates of reinfection. Recently, several new human trematode pathogens have been identified. Novel approaches to chemoprophylaxis and vaccination may alleviate the public health problem caused by Chinese helminths. However, recombinant helminth vaccine development will depend on first cataloguing the extensive genetic diversity of Chinese helminths and candidate vaccine antigens. Evidence from biogeography, genetics, and systematics suggests that the genetic diversification of Chinese helminths and their vectors is an ongoing evolutionary process that began 12 million years ago near the convergence of major Asian river systems. Construction of the Three Gorges Super Dam on the Yangtze River may promote the emergence and reemergence of new helminths and their snail vector

    Loop Corrections to Cosmological Perturbations in Multi-field Inflationary Models

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    We investigate one-loop quantum corrections to the power spectrum of adiabatic perturbation from entropy modes/adiabatic mode cross-interactions in multiple DBI inflationary models. We find that due to the non-canonical kinetic term in DBI models, the loop corrections are enhanced by slow-varying parameter ϵ\epsilon and small sound speed csc_s. Thus, in general the loop-corrections in multi-DBI models can be large. Moreover, we find that the loop-corrections from adiabatic/entropy cross-interaction vertices are IR finite.Comment: 21 pages, 7 figures; v2, typos corrected, ref added; v3 typos corrected, version for publishing in jca

    Primordial Trispectrum from Entropy Perturbations in Multifield DBI Model

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    We investigate the primordial trispectra of the general multifield DBI inflationary model. In contrast with the single field model, the entropic modes can source the curvature perturbations on the super horizon scales, so we calculate the contributions from the interaction of four entropic modes mediating one adiabatic mode to the trispectra, at the large transfer limit (TRS≫1T_{RS}\gg1). We obtained the general form of the 4-point correlation functions, plotted the shape diagrams in two specific momenta configurations, "equilateral configuration" and "specialized configuration". Our figures showed that we can easily distinguish the two different momenta configurations.Comment: 17pages, 7 figures, version to appear in JCA
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