Atherosclerosis is a world-wide disease with severe effects on human health. Although it remains unclear about the pathological mechanisms of atherosclerosis that can not be efficiently prevented and treated so far, a large body of evidence suggests that increased level of plasma homocysteine is an independent risk factor for atherosclerosis. Numerous studies have found a close relationship between hyperhomocysteinemia and oxidative stress, endoplasmic reticulum stress, endothelial cell injury as well as increased viscosity of blood, but the underlying mechanisms are largely unknown. This brief review introduces protein homocysteinylation, to which more and more researchers abroad begin to pay attention. We mainly focus on homocysteinylation of antioxidant enzymes, endoplasmic reticulum resident proteins, coagulation factors, low-density lipoprotein and calcium signaling-related proteins. To elucidate an importance of protein homocysteinylation in the development of atherosclerotic plaque, we also describe how homocysteine and its derivative homocysteine thiolactone covalently modify proteins, by which the structure and physical-chemical properties of target molecules are altered.
In this paper, we construct a family of algebraic curves over Q with many elements in the K2 group. Some interesting linear relationships between these elements are proved. Moreover, the integrality property of these elements is discussed.
We consider the following semilinear elliptic equation - Δ u-μ u ｜x｜2 =g(x,u)+｜u｜2*-2u in Ω with Dirichlet boundary condition, where g(x,·) has subcritical growth at infinity. The existence of positive solutions are obtained by variational method in the spirit of Brézis-Nirenberg.
In this paper, we study the valuations of rational nondiscrete type. Let K be a 2-dimensional purely transcendental field extension of k. By defining the φ-degree of a monomial when φ is a formal series satisfying some given conditions, we show that every k-valuation of K can be defined by a transcendental formal series.
The incidence of zero counts is often greater than expected for the Poisson distribution and zero counts frequently have special status. And sometimes the count data may be grouped, which means that for some observation the count is not known exactly but is known to fall in a particular range. This paper considers a semiparametric zero-inflated Poisson (ZIP) model to fit such grouped data with excess zeros, where the partial linear link function is used in the mean of the Poisson distribution and the linear link function is used in modeling the probability of zero. A Sieve maximum likelihood estimator(MLE) is proposed to estimate both the regression parameters and the nonparametric function, and a score test is provided for the presence of excess zeros. Asymptotic properties of the proposed Sieve MLEs are discussed. Under some mild conditions, the estimators are shown to be strong consistent. Moreover, the estimators of the unknown parameters are asymptotic efficient and normally distributed. The estimator of the nonparametric function has optimal convergence rate. Simulation studies are carried out to investigate the performance of the proposed method. For illustration purpose, the method is applied to a data set from a public health survey.
An HCMU metric is a kind of extremal metric with conical singularities on a Riemann surface. It can be characterized by a meromorphic 1-form. In this paper we give some important properties of this meromorphic 1-form. As an application we prove the sufficient and necessary condition of the Gauss curvature of an HCMU metric being smooth.
Platinum clusters adsorbed the BO molecule are investigated systematically by using the hybrid density functional approach (B3LYP). Geometries, stabilities, and electronic structures of Pt<em>nBO clusters with different spin multiplicities are presented and discussed. The calculated results indicate that the boron and oxygen atoms are regarded as an entire molecule being adsorbed on platinum clusters, and the adsorption mode varies with the sizes of clusters. Natural populations and Mulliken populations analyses show that charges transfer from platinum atoms to the BO molecule. In addition, the calculated fragmentation energies and the averaged atomic binding energies demonstrate that the quartet Pt4BO geometry is the most stable structure of all different sized clusters.
Research on spatial matching of spaceborne radar data and ground radar data is important both in theory and application. The data matching method adopted by NASA Goddard Space Flight Center (GSFC) is introduced, and a refined 3-D grid is put forward. Three groups of spaceborne and ground radar data are matched using the two means. Qualitative comparisons and point-to-point quantitative comparisons are made, so as to analyze and test the effectiveness of the proposed method.
Multiway Principal Component Analysis (MPCA) is a multivariable statistical approach, which can extract several principal components from the numerous of data to express the data information well, and is mainly used in batch process. In practice, for many reasons, the runtime of each batch is different from others so that the effective statistical model can not be built directly. Orthonormal Function Approximation (OFA) is a technique of project transformation based on orthonormal base, after OFA we can use the projection coefficient to express the characteristics of the original data and synchronize the trajectories of each historical batch and reduce the dimension. This paper presents some improvement on the OFA and combined the MPCA to model and monitor the typical batch process——Penicillin fermentation process. The simulation results show that the improved OFA can deal with data more quickly and the improved OFA-MPCA is able to synchronize the trajectories of all the batches, and monitor the batches perfectly.
This paper investigates LHCP (left-hand circularly-polarized) antenna orientation strategy for bistatic radar, configured of GPS (Global Positioning System) and receiver on-board LEO (Low Earth Orbit) spacecraft, for oceanographic remote sensing. The relationship between the distribution of specular points and LEO height is analyzed. The influences of the GPS elevations on the shape of iso-delay ellipses, iso-doppler hyperbola and other characteristics of glistening zone are also discussed. A high gain LHCP antenna orientation strategy is proposed, considering these factors as follows: the interest sea area location, LHCP antenna beam area, the orbit characteristic of LEO satellite and the GPS elevation distribution at specular points. According to the orbit of our possible LEO satellite in the potential bistatic radar, we present an optimal combination of LHCP antenna beam solid angle and pointing orientation. The simulation of this strategy indicates good results in oceanographic remote sensing. It can be an important reference for LHCP antenna design of the future bisatic radar.
Gram-Schmidt algorithm is one of the fundamental methods in linear algebra, which is mainly used to compute QR decomposition. The classical and modified Gram-Schmidt are both based on level 1 or level 2 BLAS operations which have low cache reuse. In this paper, a new block Gram-Schmidt algorithm is proposed. The new algorithm ensures the orthogonality of resulting matrix Q is close to machine precision and improves performance because of using level 3 BLAS. Numerical experiments confirm the favorable numerical stability of the new algorithm and its effectiveness on modern computers.
Considering the big error and low accuracy in traditional CFAR segmentation based on Weibull model, the paper proposes the improving methods that the samples of the specific azimuth are processed using vertical median filter before segmentation and the zone growth filtering method is used to filter the noise points. The improving methods are compared with the traditional CFAR segmentation and the counting filtering by using the segmentation evaluation standards of gray-level contrast and ultimate measurement accuracy. The experimental result using the MSTRA samples demonstrates that the new methods improve the segmentation accuracy and the segmentation results are superior to the traditional CFAR segmentation methods.
This paper presents a novel image representation and compression framework using edge and gradient fields. The original image was represented with the pixels in edge region and the gradient fields in non-edge region, and they were encoded separately. At the encoder side, the edge region map was encoded using an adaptive quadtree decomposition and 1D wavelet transform, and the gradient fields were encoded using standard 2D wavelet coder. At the decoder side, a gradient domain variation reconstruction method was utilized to restore the decoded image from the resulting edge region and gradient fields after inverse transform. The proposed framework can provide both lossless and lossy image compression in high compression rate, and can avoid the so-called ring phenomena near edges effectively.
We presented one method to construct a scalable 4×5 high resolution parallel display matrix system with SAGE and Vizroll techniques, which was driven by one distributed PC-Cluster system. The integration of hardware architecture, system environment and software implementations involved in this deployment, together with the graphic and color calibration, were addressed in detail. Several applications of applying this high resolution parallel visualization system to geoscience community proved the feasibility and scalability of this cyberinfrastructure construction scenario.
Since the mining cities in central Liaoning region are important energy production and heavy industry base in China, the research on their air quality trends and driving factors will improve the status of air quality deterioration and prompt the balanced development between economy and ecosystem. Based on the data of air quality from the long-term monitoring stations in Anshan, Fushun and Benxi, the air quality trends and driving factors of mining cities in central Liaoning during 2001 and 2006 were analyed by Daniel's trend test method. Results showed that: from 2001 to 2006, the urban air pollution was serious in the mining cities of central Liaoning. Based on the Ⅱ standard in "The standard of environmental air quality" (GB3095-1996), the dust each month and PM10 exceeded the standard all the years, the SO2 exceeded the standard in part years, so they showed a coal smoke pollution typically. The change of various pollutants in Anshan was not clear, while the SO2 concentration increased, and the other pollutants showed a downward trend; the PM10 concentration in Fushun showed a downward trend significantly(p<0.1), and the other pollutants showed an upward trend, the NO2 increased significantly(p<0.1); the various pollutants in Benxi showed a downward trend. The spatial-seasonal differentiation of air pollution was significant, the pollution concentration in winter and spring was higher than that in summer and autumn, and the pollution concentration in industry and traffic areas were significantly higher than that in residential and clean areas. The main driving factors of the environmental air quality trends of the mining cities in central Liaoning region were energy demand pressures, environmental protection measures, urban unique geographical location and weather conditions. Therefor, in order to improve the air quality of the mining cities in central Liaoning region, we should improve the energy consumption structure, strengthen motor vehicle emissions management, make a rational urban layout, increase the capacity of the atmospheric environment including all the cities in central Liaoning region.
The interaction between interplanetary shock (IS) and corotating high speed stream (CHSS) was investigated in this paper using a 3-D kinematic method (HAF model). By changing the input conditions, such as the intensity and the location of flares, the influence of the interaction on the arrival time of CHSS was analyzed at first. Then the shock propagation effected by the interaction was studied. The simulation results showed that: (1) The interaction between IS and CHSS can influence their arrival time; (2) CHSS compressed by IS arrived earlier. Moreover, the arrival time of CHSS was associated with the intensity and location of IS's solar sources, flares. With the longitude distance between the flare and the current sheet in front of CHSS decreasing, and the flare intensity getting stronger, CHSS arrived earlier; (3) The propagation of IS under the background of CHSS was faster. But the interaction made much less influence on IS comparing with CHSS; (4) When a flare was situated at the eastern of the current sheet in front of CHSS, the shape of IS driven by the flare maybe changed and displayed two peaks structure.
Plasma antenna with cylindrical configuration is analyzed by a straightforward application of the finite-difference time-domain (FD-TD) method. The computed results of the antenna, including radiation pattern, input impedance and radiation efficiency, are shown compared with metallic antenna. The result shows that these quantities vary with the parameters of plasma including plasma electric density and collision frequency. Plasma antenna can replace metallic antenna with the advantages of reconfigurability and invisibility. It is meaningful and instructional for the optimization of the plasma antenna design.
A high activity glucosidase, which can hydrolyze glycosides, was isolated from Aspergillus niger S strain. The enzyme was purified to one spot after ammonium sulfate precipitation, ion exchange & size exclusion chromatography and its molecular weight was about 165ku, which was quite differ from other reported glucosidase. The optimum temperature of this enzyme was 50℃ & the optimum pH was pH 5~10. Based on the HPLC result, this enzyme can transform glycone to aglycone of isoflavones & resveratrol with high specific activity.
In the present thesis, the conformational changes of β-amyloid peptide, the dynamic binding and unbinding processes of huperzine A to acetylcholinesterase, and the conformational movement associated with the open or close gating mechanism of nicotinic acetylcholine receptor have been investigated using conventional and/or steered molecular dynamics simulations, gaining new and useful insights for the pathogenetic mechanism of Alzheimer's disease (AD), and providing new clues for discovering new anti-AD drugs.