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1.
Recent studies show that long non-coding RNAs (lncRNAs) play important roles in the regulation of various biological processes, including chromatin remodeling, dosage-compensation, imprinting, and epigenetic regulation. Aberrant expression of lncRNAs is involved in many complex human diseases, including cancer. In this review, we summarized recent progress on lncRNAs detection methodology with emphasis on their functions and potential implication in cancer diagnosis and therapy.  相似文献   

2.
Objective To find out more extrema simultaneously including global optimum and multiple local optima existed in multi-modal functions. Methods Germinal center is the generator and selector of high-affinity B cells, a multicellular group's artificial immune algorithm was proposed based on the germinal center reaction mechanism of natural immune systems. Main steps of the algorithm were given, including hyper-mutation, selection, memory, similarity suppression and recruitment of B cells and the convergence of it was proved. Results The algorithm has been tested to optimize various multi-modal functions, and the simulation results show that the artificial immune algorithm proposed here can find multiple extremum of these functions with lower computational cost. Conclusion The algorithm is valid and can converge on the satisfactory solution set D with probability 1 and approach to global solution and many local optimal solutions existed.  相似文献   

3.
Slopes consisting of interbedded strata of soft and hard rock mass,such as purplish red mudstone and grey-brow arkosic sandstone of Jurassic age,are very common in Sichuan basin of China.The mudstone is soft while the sandstone is hard and contains many opening or closing joints with a high dip angle.Some are nearly parallel and the others are nearly decussated with the trend of the slopes.Many natural slopes are in deformation or sliding because of those reasons.The stability of cutting slopes and supporting method to be taken for their stability in civil engineering are important.in this paper,the stability and deformation of the slopes are studied.The methods of analysis and support design principle are analyzed also.Finally,the method put forward is applied to study Fengdian high cutting slope in Sichuan section of the express way from Chengdu to Shanghai.The results indicate that the method is effective.  相似文献   

4.
For the realization of green communications in cognitive radio ad hoc networks(CRAHNs), selfadaptive and efficient power allocation for secondary users(SUs) is essential. With the distributed and timevarying network topology, it needs to consider how to optimize the throughput and power consuming, avoid the interference to primary users(PUs) and other SUs, and pay attention to the convergence and fairness of the algorithm. In this study, this problem is modeled as a constraint optimization problem. Each SU would adjust its power and corresponding strategy with the goal of maximizing its throughput. By studying the interactions between SUs in power allocation and strategy selection, we introduce best-response dynamics game theory and prove the existence of Nash equilibrium(NE) point for performance analysis. We further design a fully distributed algorithm to make the SUs formulate their strategy based on their utility functions, the strategy and number of neighbors in local area. Compared with the water-filling(WF) algorithm, the proposed scheme can significantly increase convergent speed and average throughput, and decrease the power consuming of SUs.  相似文献   

5.
Fiber Bragg grating (FBG) based sensors offer important advantages over traditional instrumentation with regards to real-time structural health monitoring (SHM) of composite materials and structures in recent years. FBG sensors, integrated into existing structures or embedded into new ones, have played a major role in assessing the safety and integrity of engineering structures. In this paper, a review on the latest research of the FBG-based SHM technique for composite field is presented. Firstly, the FBG sensing principle is briefly discussed and FBG and several other optical fiber sensors (OFSs) for SHM are performance-compared. Then, several examples of the use of FBG sensors in composite SHM are illustrated, including those from the field of cure monitoring, civil engineering, aviation, aerospace, marine and offshore platform. Finally, some existing problems are pointed out and some proposals for further researches are provided.  相似文献   

6.
Objective On the basis of developing a new animal model for oxyhemoglobin (OxyHb) injection into subarachnoid space in mice, this research was to explore the temporal dependence and spatial distribution of OxyHb- induced apoptosis in the mouse brain cells in vivo and the mechanism of neurocyte injury induced by OxyHb. Methods The animal model for OxyHb injection into subarachnoid space in mice was developed. Mice were divided randomly into the experimental group (n=40) and the control group (n= 35). The control group received saline injection (50 μL ) and the experimental group received OxyHb injection (50 μL ), both into the subarachnoid space. The mice of the two groups were subdivided according to different postoperative time (3 h, 6 h, 12 h, 24 h and 48 h). The apoptosis or necrosis of cells was distinguished with microscopy (HE staining), transmission electron microscopy and TUNEL method. Results The distribution of apoptosis was mainly in the ipsilateral neocortex and bilateral hippocampal gyrus. The apoptotic mouse brain cells showed morphological changes in the experimental group by HE staining and transmission electron microscopy. The count of TUNEL-positive cells showed substantial increase in the experimental group, and there was a significant difference between the control and experimental groups, and the number of OxyHb- induced apoptotic cells decreased with time. Conclusion OxyHb in subarachnoid space in mice can induce apoptasis, but not necrosis of mouse brain cells in viro. The apoptotic brain cells show the pattern of temporal dependence and spatial distribution. It is suggested that the early treatment should be the method of first choice for treating the hemorrhagic brain injury.  相似文献   

7.
Nanotechnology is a rapidly growing science of producing and utilizing nano-sized particles. These nanomaterials are already having an impact on health care. Nowadays we are using nanoproducts in various fields,and this leads to direct and indirect exposure in human. Skin is the largest organ of the body and functions as the first-line barrier between the external environment and the internal organs of the human body. Then people worry about the nanoparticle(NP) small enough to penetrate the skin. The potential of solid NPs to penetrate the stratum corneum and to diffuse into underlying structures raises a considerable health and safety issue for their topical use. We review the current state of knowledge on the potential risk to human health presented by skin penetration of NPs nanotechnologies, and explore the robustness of current research strategies and directions to ensure the development of "safe" and publicly accepted nano-based products and technologies.  相似文献   

8.
Based on the indirect Trefftz approach, a wave number method (WNM) is proposed to deal with three-dimensional steady-state acoustic problems. In the WNM, the dynamic pressure response variable is approximated by a set of wave functions, which exactly satisfy the Helmholtz equation. The set of wave functions comprise the exact solutions of the homogeneous part of the governing equations and some particular solution functions. The unknown coefficients of the wave functions can be obtained by enforcing the pressure approximation to satisfy the boundary conditions. Compared with the boundary element method (BEM), the WNM have a smaller system matrix, and is applicable to the radiation problems since the wave functions are independent of the domain size. A 3D acoustic cavity is exemplified to show the properties of the method. The results show that the wave number method is more efficient than the BEM, and it is fairly accurate.  相似文献   

9.
Orifice plate energy dissipater as well as plug energy dissipater, as a kind of effective energy dissipater with characteristics of simple structure, convenient construction and high energy dissipation ratio, has become welcomed more and more by hydraulics researchers. The two kinds of energy dissipaters with sudden reduction and sudden enlargement forms are similar in energy dissipation mechanism, but there are differences in energy dissipation characteristics and cavitation characteristics. In the present paper, the differences between orifice plate and plug in energy loss coefficient, relating to their energy dissipation ratio, in the backflow region length, relating to their energy loss coefficient, and in the lowest wall pressure coefficient, relating to their cavitations risk, were analyzed by numerical simulations and physical experiment, and their features in above three aspects were also revealed. The results of research in the present paper demonstrate that the backflow region length of orifice plate is longer than that of plug at the same contraction ratio, the lowest wall pressure coefficient of plug is smaller than that of orifice plate at the same contraction ratio, and the energy loss coefficient of orifice plate is bigger than that of plug, which illustrates that plug is superior to orifice plate in resistance cavitation damage at the same contraction ratio.  相似文献   

10.
The basic principoles of GPS(Global Positioning System)and DGPS(Differential GPS) are described.The Principle and structure of vehicle navigation systems,and its application to the urban traffic flow guidance are analyzed.Then,an area-corrdinated adaptive control system based on DGPS and a traffic flow guidance information system based on DGPS are put forward,and their working principles and functions are researched.This is to provides a new way for the development of urban road traffic control systems.  相似文献   

11.
Considering the diversities and ambiguities of opinion expressions in Chinese online product reviews,normal sentiment analysis technologies have exposed their inadequateness in both classification accuracy and identifying effectiveness.We propose a novel approach which can easily identify product features and corresponding opinions by building a domain-specific affective ontology and thus mapping comment sentences to the objects defined in the affective ontology.Ontology is created automatically by processing the online reviews;both product features and affective words are presented as nodes which are connected to each other by their semantic relationship.Furthermore,in order to increase the accuracy,we introduce a dynamic polarity detection technique for affective words whose sentimental tendencies are dependent on particular contexts.The experimental results clearly demonstrate the performance improvement of our approach compared with others in real world online product reviews for classification tests.  相似文献   

12.
Using the method of separation of variables in the elliptical coordinate system, a recursive formula for the electromagnetic fields in a confocal elliptical waveguide filled with multi-layered homogeneous isotropic media is derived; then the eigenequation for it is given. When an elliptical waveguide becomes a circular waveguide, the electromagnetic fields and the eigenequation of the circular waveguide can be obtained from the eigenequation of the elliptical waveguide using the asymptotic formulae of Mathieu and modified Mathieu functions for a large radial coordinate in the elliptical coordinate system, and the eigenequation of a circular waveguide filled with multilayered dielectrics can be treated as a special case of an elliptical waveguide.In addition, some numerical examples are presented to analyze the propagating characteristics influenced by the perrnittivity, permeability of dielectrics filled in the elliptical waveguide, etc. The results show that changing the permittivity or permeability of the dielectrics filled in the waveguide and the major semiaxis value of the i-th layer can change the propagating characteristics of an elliptical waveguide.  相似文献   

13.
It is an important subject to probe the structure in the medium by various kinds of detection methods in the geotechnical engineering. Based on the propagation theory of elastic wave in half-space layered medium, the propagation characteristics of elastic wave in layered medium with different elastic parameters are discussed using dynamic analysis of finite element method. It is known that the S-wave velocity, density and thickness of layer are related to the properties of the elastic wave including waveform characteristics, spectral characteristics and time-frequency characteristics. We pay special attention to the structure with low velocity interlayer. The impact imaging method is applied to the grouting construction of the immersed tube tunnel. Data acquisition and analytical method are introduced in detail. The grouting effects can be qualitatively evaluated by comparing the characteristics of elastic wave before grouting with those after grouting. Finally, a quantitative evaluation is obtained according to the relationship between energy response of elastic wave and impedance ratio.  相似文献   

14.
AbstractIn order to explore the production of hydroxyl radical(·OH)in a confined space,a novel ozone-light irradiation system is constructed in this study,and the·OH radical is measured by spin-trapping electron spin resonance(ESR)method in which 5,5-dimethyl-1-pyrroline-N-oxide(DMPO)is selected as the spin-trap.Several influence factors including the light intensity,the irradiation time and DMPO mass concentration are discussed. The results show that in this experimental system,with DMPO mass concentration of 1g/L and the irradiation time of 30 min,the·OH radical can be best captured.Besides,both wavelength and intensity of the irradiation light could effect the generation of·OH radical.These results are of great importance to further study the sterilization effect of·OH radical in confined space.  相似文献   

15.
Pollution of soil environment has become a se-rious problem in many countries, including China.Heavy metal (HM) and polycyclic aromatic hydro-carbons (PAHs) are two of the most abundant andpotentially harmful pollutants found in most pol-luted soil[1, 2]. Besides their natural occurrence,heavy metals may enter the soil environmentthrough anthropogenic activities, such as mining,smelting, sewage sludge disposal, application ofpesticides and inorganic fertilizers, and atmospher-ic deposition. …  相似文献   

16.
Oil-based nanofluids including 0.75%—1.75%(mass fraction) carbon nanotubes(CNTs) without any surfactants have been synthesized by a two-step process. The probes machined from 45~# steel with 22 mm diameter and 50 mm length are quenched in the as-synthesized CNT nanofluids for testing the cooling behaviors of the nanofluids. The laser diffraction particle size analyzer, scanning electronic microscope(SEM), X-ray diffractometer and transmission electron microscope(TEM) are used to characterize the quality and distribution of CNTs in the nanofluids. The wettability and viscosity of 30~# oil and oil-based CNT nanofluids are measured by a goniometer at 15℃ and a rotational type viscometer at 40℃, respectively. The results show that the cooling efficiency of the oil-based CNT nanofluids is better than that of 30~# oil. Moreover, the cooling rate of the naonofluids increases with the further increase of the CNT concentration. When the mass fraction of CNTs increases to 1.75%, the cooling rate of the naonofluids reaches a maximum at 760℃ and it is increased by 77.8% as compared to that of base oil. The improved cooling rate of oil by CNTs is mainly due to the uniform distribution and excellent thermal conductivity of CNTs.  相似文献   

17.
A finite element formulation was presented for the nonlinear free vibration of thin-walled curved beams with non-symmetric open across section. The kinetic and potential energies were derived by the virtual principle. The energy function includes the effect of fiexural-torsional coupling, the torsion warping and the shear centre location. For finite element analysis, cubic polynomials were utilized as the shape functions of the two nodal thin-walled curved elements. Each node possesses seven degrees freedom including the warping degree of freedom. The nonlinear eigenvalue problem was solved by the direct iteration technique. The results are compared with those for straight beams as available in the literature. The results for nonlinear free vibration analysis of curved beams for various radii and subtended angle are presented.  相似文献   

18.
The venoms of Hymenopteran social waspsand bees such as hornets, paper wasps and honey-bees are used to defend themselves and their lar-vae. Stinging with these venoms can produce se-vere pain, local damage and occasionally death inlarge vertebrates including man. Comparing withhoney bees, solitary wasps use their venoms in adifferent way, for preying on the captures. Theyinject their venoms to insects or spiders and para-lyze the preys to feed their larvae[1,2]. Melittin, theprincipal protei…  相似文献   

19.
Bacterial pore-forming toxins (PFTs) are essential virulence factors of many human pathogens. Knowl- edge of their structure within the membrane is critical for an understanding of their function in pathogenesis and for the development of useful therapy. Atomic force microscopy (AFM) has often been employed to structurally interrogate many membrane proteins, including PFTs, owing to its ability to produce sub-nanometer resolution images of samples under aqueous solution. However, an absolute prerequisite for AFM studies is that the samples are single-layered and closely-packed, which is frequently challenging with PFTs. Here, using the prototypical member of the cholesterol-dependent cytolysin family of PFTs, perfringolysin O (PFO), as a test sample, we have developed a simple, highly robust method that routinely produces clean, closely-packed samples across the entire specimen surface. In this approach, we first use a small Teflon well to prepare the supported lipid bilayer, remove the sample from the well, and then directly apply the proteins to the bilayer. For reasons that are not clear, bilayer preparation in the Teflon well is essential. We anticipate that this simple method will prove widely useful for the preparation of similar samples, and thereby enable AFM imaging of the greatest range of bacterial PFTs to the highest possible resolution.  相似文献   

20.
Fault reconfiguration of shipboard power system is viewed as a typical nonlinear and multi-objective combinatorial optimization problem. A comprehensive reconfiguration model is presented in this paper, in which the restored loads, switch frequency and generator efficiency are taken into account. In this model, analytic hierarchy process(AHP) is proposed to determine the coefficients of these objective functions. Meanwhile, a quantum differential evolution algorithm with triple quantum bit code is proposed. This algorithm aiming at the characteristics of shipboard power system is different from the normal quantum bit representation. The individual polymorphic expression is realized, and the convergence performance can be further enhanced in combination with the global parallel search capacity of differential evolution algorithm and the superposition properties of quantum theory. The local optimum can be avoided by dynamic rotation gate. The validity of algorithm and model is verified by the simulation examples.  相似文献   

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