414 research outputs found

    Emerging Applications of Metabolomics in Traditional Chinese Medicine Treating Hypertension: Biomarkers, Pathways and More

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    Hypertension is a prevalent, complex, and polygenic cardiovascular disease, which is associated with increased mortality and morbidity. Across the world, traditional Chinese medicine (TCM) constituted by herbal medicine and non-pharmacological therapies is used to assist blood pressure management. Though widely accepted in daily practice, its mechanism remains largely unknown. Recent years saw a number of studies utilizing metabolomics technologies to elucidate the biological foundation of the antihypertensive effect of TCM. Metabolomics is a relatively “young” omics approach that has gained enormous attention recently in cardiovascular drug discovery and pharmacology studies of natural products. In this review, we described the use of metabolomics in deciphering TCM diagnostic codes for hypertension and in revealing molecular events that drive the antihypertensive effect. By corroborating the diagnostic rules, there's accumulating evidence showing that metabolic profile could be the signature of different syndromes/patterns of hypertension, which offers new perspectives for disease diagnosis and efficacy optimization. Moreover, TCM treatment significantly altered the metabolic perturbations associated with hypertension, which could be a crucial mechanism of the therapeutic effect of TCM. Not only significantly rebalances the dynamics of metabolic flux, TCM but also elicits metabolic network reorganization through restoring the functions of key metabolites, and metabolic pathways. The role of TCM in regulating metabolic perturbations will be informative to researchers seeking new leads for drug discovery. This review further envisioned the promises of employing metabolomics to explore network pharmacology, host-gut microbiota interactions and metabolic reprogramming in TCM, and possible herb-drug interactions in this field in future

    Dissipative Landau-Zener transitions in a three-level bow-tie model: accurate dynamics with the Davydov multi-D2 Ansatz

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    We investigate Landau-Zener (LZ) transitions in the three-level bow-tie model (3L-BTM) in a dissipative environment by using the numerically accurate method of multiple Davydov D2 Ansatze. We first consider the 3L-TBM coupled to a single harmonic mode, study evolutions of the transition probabilities for selected values of the model parameters, and interpret the obtained results with the aid of the energy diagram method. We then explore the 3L-TBM coupled to a boson bath. Our simulations demonstrate that sub-Ohmic, Ohmic and super-Ohmic boson baths have substantially different influences on the 3L-BTM dynamics, which cannot be grasped by the standard phenomenological Markovian single-rate descriptions. We also describe novel bath-induced phenomena which are absent in two-level LZ systems.Comment: 11 pages, 7 figure

    Dynamics of dissipative Landau-Zener transitions in an anisotropic three-level system

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    We investigate the dynamics of Landau-Zener transitions in an anisotropic, dissipative three-level model (3-LZM) using the numerically accurate multiple Davydov D2 Ansatz in the framework of time-dependent variation. It is demonstrated that a non-monotonic relationship exists between the Landau-Zener transition probability and the phonon coupling strength when the 3-LZM is driven by a linear external field. Under the influence of a periodic driving field, phonon coupling may induce peaks in contour plots of the transition probability when the magnitude of the system anisotropy matches the phonon frequency. Dynamics of the 3-LZM have also been probed in the presence of a super-ohmic phonon bath when driven by a periodic driving field. It is found that both the period and the amplitude of the Rabi cycle decay exponentially with the increasing bath coupling strength.Comment: 12 pages, 7 figure

    Do Rural Migrants Benefit from Labor Market Agglomeration Economies? Evidence from Chinese Cities

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    We combine the 2005 China Inter-Census Population Survey data and the 2004 China Manufacturing Census to test whether workers, particularly rural migrants, benefit from labor market Marshallian externalities. We find that workers in general, and rural migrants in particular, benefit from labor market pooling effect (measured by total employment in a city-industry cell) and human capital externalities (measured by share of workers with a college degree or above in a city-industry cell). These findings are robust to various sorting bias tests. However, rural migrants benefit much less than do local or urban workers, possibly because rural migrants lack social networks and are discriminated doubly in terms of being both “rural” and “migrants.” Our findings have policy implications on how Chinese cities can become skilled during the rapid urbanization process coupled with global competition

    Do Rural Migrants Benefit from Labor Market Agglomeration Economies? Evidence from Chinese Cities

    Get PDF
    We combine the 2005 China Inter-Census Population Survey data and the 2004 China Manufacturing Census to test whether workers, particularly rural migrants, benefit from labor market Marshallian externalities. We find that workers in general, and rural migrants in particular, benefit from labor market pooling effect (measured by total employment in a city-industry cell) and human capital externalities (measured by share of workers with a college degree or above in a city-industry cell). These findings are robust to various sorting bias tests. However, rural migrants benefit much less than do local or urban workers, possibly because rural migrants lack social networks and are discriminated doubly in terms of being both “rural” and “migrants.” Our findings have policy implications on how Chinese cities can become skilled during the rapid urbanization process coupled with global competition

    Jitter analysis of a superconducting nanowire single photon detector

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    Jitter is one of the key parameters for a superconducting nanowire single photon detector (SNSPD). Using an optimized time-correlated single photon counting system for jitter measurement, we extensively studied the dependence of system jitter on the bias current and working temperature. The signal-to-noise ratio of the single-photon-response pulse was proven to be an important factor in system jitter. The final system jitter was reduced to 18 ps by using a high-critical-current SNSPD, which showed an intrinsic SNSPD jitter of 15 ps. A laser ranging experiment using a 15-ps SNSPD achieved a record depth resolution of 3 mm at a wavelength of 1550 nm.Comment: 7 pages, 6 figure

    Estimation of shear stress by using a myocardial bridge-mural coronary artery simulating device

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    Background: This study was aimed at developing a myocardial bridge-mural coronary artery simulative device and analyzing the relationship between shear stress on the mural coronary artery and atherosclerosis. Methods: A myocardial bridge-mural coronary artery simulative device was used to simulate experiments in vitro. In the condition of maintaining any related parameters such as system temperature, average flow rate, and heart rate, we calculated and observed changes in proximal and distal mean values, and oscillatory value of shear stress on the mural coronary artery by regulating the compression level of the myocardial bridge to the mural coronary artery. Results: Under 0% compression, no significant differences were observed in distal and proximal mean values and oscillatory value of the shear stress on the mural coronary artery. With the increase in the degree of compression, the mean shear stress at the distal end was greater than that at the proximal end, but the oscillatory value of the shear stress at the proximal end was greater than that at the distal end. Conclusions: The experimental results of this study indicate that myocardial bridge compression leads to abnormal hemodynamics at the proximal end of the mural coronary artery. This abnormal phenomenon is of great significance in the study of atherosclerosis hemodynamic pathogenesis, which has potential clinical value for pathological effects and treatments of myocardial bridg
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