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排序方式: 共有494条查询结果,搜索用时 15 毫秒
111.
Osterne Vinicius J. S. Verduijn Joost Lossio Claudia F. Parakhonskiy Bogdan Oliveira Messias V. Pinto-Junior Vanir R. Nascimento Kyria S. Skirtach Andre G. Van Damme Els J. M. Cavada Benildo S. 《Journal of Materials Science》2022,57(19):8854-8868
Journal of Materials Science - Cancer is a serious health problem mainly characterized by unregulated cell divisions. It is known that malign cells display cancer-specific glycans that can be... 相似文献
112.
M Seiki 《Canadian Metallurgical Quarterly》1999,26(1):157-161
Oscillations of cytosolic free calcium levels have been shown to influence gene regulation and cell differentiation in a variety of model systems. Intercellular calcium waves thus present a plausible mechanism for coordinating cellular processes during embryogenesis. Herein we report use of aequorin and a photon imaging microscope to directly observe a rhythmic series of intercellular calcium waves that circumnavigate zebrafish embryos over a 10-h period during gastrulation and axial segmentation. These waves first appeared at about 65% epiboly and continued to arise every 5-10 min up to at least the 16-somite stage. The waves originated from loci of high calcium activity bordering the blastoderm margin. Several initiating loci were active early in the wave series, whereas later a dorsal marginal midline locus predominated. On completion of epiboly, the dorsal locus was incorporated into the developing tail bud and continued to generate calcium waves. The locations and timing at which calcium dynamics are most active appear to correspond closely to embryonic cellular and syncytial sites of known morphogenetic importance. The observations suggest that a panembryonic calcium signaling system operating in a clock-like fashion might play a role during vertebrate axial patterning. 相似文献
113.
Noriko Takemura Yutaka Nakamura Yoshio Matsumoto Hiroshi Ishiguro 《Artificial Life and Robotics》2010,15(1):111-116
This article deals with a path-planning problem in tracking humans in order to obtain detailed information about human behavior and characteristics. In our method, path planning is performed based on Kullback-Leibler (KL) divergence between the predicted distribution of all human positions and the intensity of the field of view of the agents. The number of steps predicted is determined according to the consistency of the prediction. Experimental results show that when the prediction of human movement is accurate, long-term prediction is useful for path planning. On the other hand, when prediction is inaccurate, long-term prediction might not be useful. Our path-planning method works well even under changing circumstances by changing the length of the predictions. 相似文献
114.
Surface polyion complex (sPIC) gels were prepared with a nonionic hydrogel interior core, composed of poly(N‐vinylformamide and poly(N‐vinylacetamide), and a chemically bounded polyion complex layer on the outer surface, composed of poly(vinylamine) and poly(acrylic acid). The gels were investigated as controlled drug release models based on electrostatic interactions depending on pH. Methylene blue and allura red were employed as cationic and anionic drug models, respectively, and resulted in the selective adsorption depending on pH conditions. Monovalent and multivalent anionic drug models, allura red and 1,3,6‐naphthalenetrisulfonate were observed for their releasing behavior from the sPIC gel. The results indicated that the multivalent anionic drug effectively controlled release depending on pH conditions. We further investigated sPIC gels regarding their ability to control the release of ionic molecules as a function of pH‐driven changes in electrostatic interactions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42081. 相似文献
115.
Magnovaldo Carvalho Lopes Vinicius Gomide de Castro Luciana Moreira Seara Vitor Perige Almeida Diniz Rodrigo Lassarote Lavall Glaura Goulart Silva 《应用聚合物科学杂志》2014,131(23)
In this study, composites based on a thermoset polyurethane elastomer (PU) and multiwalled carbon nanotubes (MWCNT) in the case of a PU of high elastic modulus (>200 MPa) are analyzed for the first time. As‐grown and modified nanotubes with 4 wt % of oxygenated functions (MWCNT‐ox) were employed to compare their effect on composite properties and maxima mechanical properties (elastic modulus and tensile strength) were reached at 0.5 wt % of MWCNT‐ox. Furthermore, by examining the morphology using optical and electron microscopies better dispersion and interaction of the nanotube‐matrix was observed for this material. DMTA data supports the observation of an increase in the glass transition temperature of ~20°C in the nanocomposites compared with the thermoset PU, which is an important result because it shows extended reliability in extreme environments. Finally, nanoindentation tests allowed a comparison with the conventional mechanical tests by measuring the elastic modulus and hardness at the subsurface of PU and the nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41207. 相似文献
116.
A tunable multimode unidirectional traveling-wave Ti:sapphire laser was developed to measure in situ the atmospheric absorption spectra using intracavity absorption spectroscopy. The effective absorption path length was 2100 km. O2 and H2O vapor lines in atmosphere with absorption coefficients of 10(-6)-10(-8) cm(-1) were measured with uncertainties <5%, and the absorption coefficients were in agreement with those estimated from the HITRAN database. By tuning the wavelength, a weak absorption line with an absorption coefficient of 10(-9) cm(-1) was measured with a sensitivity of 2×10(-10) cm(-1). The sensitivity was limited by the residual parasitic variation that appeared in the spectrum. 相似文献
117.
Gustavo Henrique Carvalho Marcus Vinicius Cianciaruso Marco Antônio Batalha 《Environmental Modelling & Software》2010,25(6):815-816
Plantminer is a web tool designed to reduce the effort of compiling, checking, and formatting seed plants species data. It will search for orders, families, authors, synonyms, and make sure that all species in a plant species list exist or are correctly spelled. Plantminer also compares species in pairs, removing duplicated entries, warning the user when there are synonyms in the submitted list, and replacing them by the currently accepted names. The output is compiled in tab-delimited text files, which are compatible with most statistical packages. Plantminer covers seed plant species on a global basis. 相似文献
118.
Liana Barachisio Lisboa Vinicius Cardoso Garcia Daniel Lucrédio Eduardo Santana de Almeida Silvio Romero de Lemos Meira Renata Pontin de Mattos Fortes 《Information and Software Technology》2010,52(1):1-13
The domain analysis process is used to identify and document common and variable characteristics of systems in a specific domain. In order to achieve an effective result, it is necessary to collect, organize and analyze several sources of information about different applications in this domain. Consequently, this process involves distinct phases and activities and also needs to identify which artifacts, arising from these activities, have to be traceable and consistent. In this context, performing a domain analysis process without tool support increases the risks of failure, but the used tool should support the complete process and not just a part of it. This article presents a systematic review of domain analysis tools that aims at finding out how the available tools offer support to the process. As a result, the review identified that these tools are usually focused on supporting only one process and there are still gaps in the complete process support. Furthermore, the results can provide insights for new research in the domain engineering area for investigating and defining new tools, and the study also aids in the identification of companies’ needs for a domain analysis tool. 相似文献
119.
Tomokazu Sato Masayuki Kanbara Naokazu Yokoya Haruo Takemura 《International Journal of Computer Vision》2002,47(1-3):119-129
Three-dimensional (3-D) models of outdoor scenes are widely used for object recognition, navigation, mixed reality, and so on. Because such models are often made manually with high costs, automatic 3-D reconstruction has been widely investigated. In related work, a dense 3-D model is generated by using a stereo method. However, such approaches cannot use several hundreds images together for dense depth estimation because it is difficult to accurately calibrate a large number of cameras. In this paper, we propose a dense 3-D reconstruction method that first estimates extrinsic camera parameters of a hand-held video camera, and then reconstructs a dense 3-D model of a scene. In the first process, extrinsic camera parameters are estimated by tracking a small number of predefined markers of known 3-D positions and natural features automatically. Then, several hundreds dense depth maps obtained by multi-baseline stereo are combined together in a voxel space.So, we can acquire a dense 3-D model of the outdoor scene accurately by using several hundreds input images captured by a hand-held video camera. 相似文献
120.
Isao Shirakawa Seiki Kyan Hiroshi Ozaki 《International Journal of Circuit Theory and Applications》1975,3(1):71-80
The coefficient matrix of a fairly large system of equations is generally very sparse. Thus in the computer-aided analysis of such a system of equations, of prime importance are the sparsity-oriented solution and storage techniques. Motivated by this problem, in the present paper we first define a bipartite network associated with a given system of equations, and then discuss the problem of sparsity-preserving pivot ordering with the use of the bipartite network. 相似文献