2,900 research outputs found
Mixed-phase wavelet estimation by iterative linear inversion of high-order statistics
This is a review paper on the mixed-phase wavelet estimation using high-order statistics. We use an iterative linear inversion method as a primary thread, stringing together others including the maximum time-delayed moment (MTM) method and the normalized cumulant (NC) method. Both MTM and NC methods are not stable, because they make use of only single high-order-statistics slices. As for the iterative linear inversion method, it is stable but needs a good initial model. Therefore, we adopt a hybrid strategy that uses the MTM or NC method to generate an initial estimate of the wavelet for the iterative linear inversion method. The real seismic data test has shown that all inversions with different initial models converge to the same result within allowable accuracy. Therefore, the iterative linear inversion method is applicable to real multi-channel seismic data for wavelet estimation
Cyclic behaviour of connecting beams in reinforced concrete slit shear walls
The connecting beams in slit shear walls are generally much shorter than those in ordinary coupled shear walls and may therefore behave quite differently. In order to investigate the shear behaviour of such short connecting beams, two series of shear tests, one on monotonic behaviour and the other on cyclic behaviour, were carried out. Altogether, 24 specimens were tested. The results of the monotonic shear tests have been reported in an earlier paper. This Paper presents some additional information on the ductility of the beams as revealed by the monotonic shear tests, and the results of the cyclic shear tests. From the cyclic shear tests, the cracking and failure characteristics, reinforcement stress distribution, stiffness and strength degradations, ductility and damping capacity, etc., of the connecting beams are studied. The results are useful for evaluating the seismic performance of reinforced concrete slit shear walls.published_or_final_versio
Anti-inflammation activity and chemical composition of flower essential oil from Hedychium coronarium
Hedychium coronarium Koen. (Family Zingiberaceae), popularly named butterfly ginger, is widely available in tropical and subtropical regions. It has been used in folk medicine for many conditions, such as contusion inflammation, anti-rheumatic and so on. In this study, chemical compositions and anti-inflammatory activity of this flowers’ essential oil were investigated for the first time. Followed by GC–MS analysis, a total of 29 components were identified and the main constituents included -transocimenone (28.05%), linalool (18.52%), 1,8-cineole (11.35%), -terpineol (7.11%), 10-epi--eudesmol (6.06%), sabinene (4.59%) and terpinen-4-ol (3.17%). We measured the antioxidant activity of the essential oil in vitro (DPPH reduction assay and ferric reducing antioxidant power assay) and the antiinflammatory activity in vivo (carrageenan-induced hind paw edema in rats). The oil (100 mg/kg p.o.) produced significant inhibition of paw oedema, but showed poor antioxidant activity (with the DPPH IC50 value of 1091.00 g/ml and FRAP value of 0.22 mol Fe2+/mg). The results reveal that there is no direct correlation between anti-inflammatory effect and antioxidant activity of this essential oil
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Density functional theory studies of hydrogen bonding vibrations in sI gas hydrates
Abstract
To analyze the vibrational modes of water and methane in structure I gas hydrates, we constructed a 178-atom supercell with two small cages of type 512 and six large cages of type 51262. We applied the density functional theory method to simulate the vibrational spectrum and normal modes of methane hydrates. In accord with our previous studies, we confirmed that two groups of hydrogen bond (H-bond) peaks (at around 291 and 210 cm−1) in the translational bands come from two kinds of intermolecular H-bond vibrational modes. This is the first investigation of H-bond vibrations in methane hydrates. The partial modes of CH4 were extracted. We found that the CH4 phonons in the translational region are below 180 cm−1 so that the influence of methane on the H-bond is insignificant. We proposed a new method to decompose gas hydrates via direct application of terahertz radiation to the H-bonds. Herein, we confirmed that CH4 molecules do not absorb this energy.</jats:p
Effect of Granulocyte-Colony Stimulating Factor on Endothelial Cells and Osteoblasts
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Effect of Ovariectomy on Stimulating Intracortical Remodeling in Rats
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Fluid flow induced calcium response in bone cell network
In our previous work, bone cell networks with controlled spacing and functional intercellular gap junctions had been successfully established by using microcontact printing and self assembled monolayers technologies [Guo, X. E., E. Takai, X. Jiang, Q. Xu, G. M. Whitesides, J. T. Yardley, C. T. Hung, E. M. Chow, T. Hantschel, and K. D. Costa. Mol. Cell. Biomech. 3:95-107, 2006]. The present study investigated the calcium response and the underlying signaling pathways in patterned bone cell networks exposed to a steady fluid flow. The glass slides with cell networks were separated into eight groups for treatment with specific pharmacological agents that inhibit pathways significant in bone cell calcium signaling. The calcium transients of the network were recorded and quantitatively evaluated with a set of network parameters. The results showed that 18 alpha-GA (gap junction blocker), suramin (ATP inhibitor), and thapsigargin (depleting intracellular calcium stores) significantly reduced the occurrence of multiple calcium peaks, which were visually obvious in the untreated group. The number of responsive peaks also decreased slightly yet significantly when either the COX-2/PGE(2) or the NOS/nitric oxide pathway was disrupted. Different from all other groups, cells treated with 18 alpha-GA maintained a high concentration of intracellular calcium following the first peak. In the absence of calcium in the culture medium, the intracellular calcium concentration decreased slowly with fluid flow without any calcium transients observed. These findings have identified important factors in the flow mediated calcium signaling of bone cells within a patterned network.</p
Symptoms of posttraumatic stress disorder and depression among bereaved and non-bereaved survivors following the 2008 Sichuan earthquake
Many studies have suggested that unexpected death of a loved one is an important risk factor of posttraumatic stress disorder (PTSD) and depression among disaster survivors, but few have examined the magnitude of psychiatric morbidities among bereaved survivors. This study examined the prevalence rates of clinically significant PTSD and depressive symptoms and their associated risk factors among Chinese adult survivors following the 2008 Sichuan earthquake. Two hundred and fifty-one bereaved adults were compared with 1474 non-bereaved adult survivors. The estimated rates of PTSD and depressive symptoms were 65.6% and 64.8% for those who lost first-degree family members, 34.1% and 45.5% for those who lost second-degree relatives, and 27.1% and 37.5% for non-bereaved survivors respectively. Loss of a child was a significant predictor of psychopathological symptoms. The results suggested that effective and sustainable mental health services were required, especially for bereaved single-child parents. © 2012 Elsevier Ltd.postprin
Multiphoton Interference in Quantum Fourier Transform Circuits and Applications to Quantum Metrology
© 2017 American Physical Society. Quantum Fourier transforms (QFTs) have gained increased attention with the rise of quantum walks, boson sampling, and quantum metrology. Here, we present and demonstrate a general technique that simplifies the construction of QFT interferometers using both path and polarization modes. On that basis, we first observe the generalized Hong-Ou-Mandel effect with up to four photons. Furthermore, we directly exploit number-path entanglement generated in these QFT interferometers and demonstrate optical phase supersensitivities deterministically
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