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991.
Dore M Matilla-Garcia M Marin MR 《Nonlinear dynamics, psychology, and life sciences》2011,15(3):407-418
This article addresses the question of improving the detection of nonlinear dependence by means of recently developed nonparametric tests. To this end a generalized version of BDS test and a new test based on symbolic dynamics are used on realizations from a well-known artificial market for which the dynamic equation governing the market is known. Comparisons with other tests for detecting nonlinearity are also provided. We show that the test based on symbolic dynamics outperforms other tests with the advantage that it depends only on one free parameter, namely the embedding dimension. This does not hold for other tests for nonlinearity. 相似文献
992.
Mohammed Abouzaid 《Advances in Mathematics》2011,228(2):894
We prove that the algebra of chains on the based loop space recovers the derived (wrapped) Fukaya category of the cotangent bundle of a closed smooth oriented manifold. The main new idea is the proof that a cotangent fibre generates the Fukaya category using a version of the map from symplectic cohomology to the homology of the free loop space introduced by Cieliebak and Latschev. 相似文献
993.
El Midaoui M Maataoui A Benbella M Houssa AA Labazi N 《Natural product communications》2011,6(10):1455-1458
By the diversity of its soil and climatic factors, Morocco offers a flora particularly rich in aromatic and medicinal plants (MAP). In order to obtain the most information about the flora (flowering times, fruiting, harvesting and their main uses in traditional medicine), a study was conducted in the mountainous Khenifra region. A survey of users of MAP (rural population, herbalists arborists) has been undertaken and was completed by field observations and sampling at different stages of growth. The results showed a range of indigenous and diversified MAP belonging to 10 botanical families (Lamiaceae, Asteraceae, Rosaceae, Chenopodiaceae, Papaveraceae, Caryophyllaceae, Cupressaceae, Rutaceae, Anacardiaceae and Zygophyllaceae). The flowering period of all species, according to the local community surveyed, spread from February (2%) to September (12%), with a significant concentration from April to June (65%).The highest rate of fructification occurred in June-July (64%). The harvesting period of the main MAP from this mountain area stretches mainly from March to April (61%). The mode of propagation stated varied among species, and concerned mainly replication by seeds (53%) and cuttings (24%). Regarding the use of these indigenous MAP as traditional medicines, all plant parts are used, especially leaves, flowers and stems. 相似文献
994.
Sid Ali Kaoua Kamel Taibi Nacera Benghanem Krimo Azouaoui Mohammed Azzaz 《Applied Mathematical Modelling》2011,35(3):1378-1387
This paper presents a 3D geometric modelling of a twin helical spring and its finite element analysis to study the spring mechanical behaviour under tensile axial loading. The spiralled shape graphic design is achieved through the use of Computer Aided Design (CAD) tools, of which a finite element model is generated. Thus, a 3D 18-dof pentaedric elements are employed to discretise the complex “wired-shape” of the spring, allowing the analysis of the mechanical response of the twin spiralled helical spring under an axial load. The study provides a clear match between the evolution of the theoretical and the numerical tensile and compression normal stresses, being of sinusoidal behaviour. The overall equivalent stress isovalues increases radially from 0° to 180°, being maximal on the internal radial zone at the section 180°. On the other hand, the minimum stress level is located in the centre of the filament cross section. 相似文献
995.
Aljallad MH Yuan J Pilatou MC McDannold NJ Panych LP 《Magnetic resonance imaging》2011,29(9):1205-1214
Purpose
The purpose was to develop a new magnetic resonance imaging technique for fast temperature monitoring with extended volume coverage.Materials and Methods
The Multiple Resolutions Along Phase-Encode and Slice-Select Dimensions (MURPS) method was implemented in both a two-dimensional (2D) spoiled gradient echo (SPGR) sequence and a multishot echo-planar imaging (EPI) sequence. Both modified sequences were used to acquire image data from three slices with variable phase-encode resolution and slice thickness. In the SPGR sequence, a 2D resonant frequency pulse was also implemented to enable imaging within a reduced field of view, and this was used to monitor (at 1.5 T) the temperature changes in a live rabbit and in gel phantoms heated by focused ultrasound. A modified EPI sequence was tested during heating of a phantom undergoing motion.Results
The in vivo experiments demonstrated that temperature changes in unexpected locations away from the focal plane, such as near bone structures, could be detected due to the extra volume coverage afforded by the MURPS method. Temperature changes in a moving phantom were resolved using the MURPS EPI sequence with an acquisition rate of three slices every 300 ms.Conclusion
The MURPS method enables temperature monitoring over multiple slices without loss of temporal resolution compared with single-slice imaging and, if combined with multishot EPI, enables volume temperature monitoring in moving organs. 相似文献996.
Khan MS Al-Suti MK Shah HH Al-Humaimi S Al-Battashi FR Bjernemose JK Male L Raithby PR Zhang N Köhler A Warren JE 《Dalton transactions (Cambridge, England : 2003)》2011,40(39):10174-10183
A series of trimethylsilyl-protected di-alkynes incorporating 3,4-ethylenedioxythiophene (EDOT) linker groups Me(3)Si-C≡C-R-C≡C-SiMe(3) (R = ethylenedioxythiophene-3,4-diyl 1a, 2,2'-bis-3,4-ethylenedioxythiophene-5,5'-diyl 2a, 2,2',5',2'-ter-3,4-ethylenedioxythiophene-5,5'-diyl 3a) and the corresponding terminal di-alkynes, H-C≡C-R-C≡C-H 1b-2b has been synthesized and characterized and the single crystal X-ray structure of 1a has been determined. CuI-catalyzed dehydrohalogenation reaction between trans-[(Ph)(Et(3)P)(2)PtCl] and the terminal di-alkynes 1b-2b in (i)Pr(2)NH/CH(2)Cl(2) (2:1 mole ratio) gives the Pt(II) di-ynes trans-[(Et(3)P)(2)(Ph)Pt-C≡C-R-C≡C-Pt(Ph)(Et(3)P)(2)] 1M-2M while the dehydrohalogenation polycondensation reaction between trans-[((n)Bu(3)P)(2)PtCl(2)] and 1b-2b (1:1 mole ratio) under similar reaction conditions affords the Pt(II) poly-ynes trans-[Pt(P(n)Bu(3))(2)-C≡C-R-C≡C-](n)1P-2P. The di-ynes and poly-ynes have been characterized spectroscopically and, for 1M and 2M, by single-crystal X-ray which confirms the "rigid rod" di-yne backbone. The materials possess excellent thermal stability, are soluble in common organic solvents and readily cast into thin films. Optical absorption spectroscopic measurements reveal that the EDOT spacers create stronger donor-acceptor interactions between the platinum(II) centres and conjugated ligands along the rigid backbone of the organometallic polymers compared to the related non-fused and fused oligothiophene spacers. 相似文献
997.
Alamiry MA Benniston AC Copley G Harriman A Howgego D 《The journal of physical chemistry. A》2011,115(44):12111-12119
Photophysical properties have been recorded for a small series of covalently linked, symmetrical dimers formed around boron dipyrromethene (Bodipy) dyes. Within the series, a control dimer is unable to adopt a cofacial arrangement because of steric factors, while a second dimer possesses sufficient internal flexibility to form the cofacial geometry but with little overlap of the Bodipy units. The other three members of the series take up a cofacial arrangement with varying bite angles between the planes of the two Bodipy units. Fluorescence quantum yields and excited-state lifetimes indicate differing extents of electronic interaction between the two Bodipy head-groups, but only the compound with the smallest bite angle exhibits excimer emission in solution under ambient conditions. Time-resolved fluorescence studies show dual-exponential decay kinetics in each case, while temperature-dependent emission studies reveal reversible coupling between monomer and lower-energy excimer states. The latter is weakly fluorescent, at best, and is seen clearly only for dimers having small bite angles. The application of high pressure to dilute solutions of these dimers promotes excimer formation in certain cases and leads to loss of monomer-like fluorescence. Under high pressure, excimer emission is more evident, and the overall results can be discussed in terms of subtle structural rearrangements that favor excimer formation. 相似文献
998.
Janjua NK Shaheen A Yaqub A Perveen F Sabahat S Mumtaz M Jacob C Ba LA Mohammed HA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(5):1600-1604
Interactional studies of new flavonoid derivatives (Fl) with chicken blood ds.DNA were investigated spectrophotometrically in DMSO-H2O (9:1 v/v) at various temperatures. Spectral parameters suggest considerable binding between the flavonoid derivatives studied and ds.DNA. The binding constant values lie in the enhanced-binding range. Thermodynamic parameters obtained from UV studies also point to strong spontaneous binding of Fl with ds.DNA. Viscometric studies complimented the UV results where a small linear increase in relative viscosity of the DNA solution was observed with added optimal flavonoid concentration. An overall mixed mode of interaction (intercalative plus groove binding) is proposed between DNA and flavonoids. Conclusively, investigated flavonoid derivatives are found to be strong DNA binders and seem to be promising drug candidates like their natural analogues. 相似文献
999.
1000.
Alsaif Nawaf A. Elwan Alaa Alanazi Mohammed M. Obaidullah Ahmad J. Alanazi Wael A. Alasmari Abdullah F. Albassam Hussam Mahdy Hazem A. Taghour Mohammed S. 《Molecular diversity》2022,26(4):1915-1932
Molecular Diversity - Vascular endothelial growth factor receptor-2 (VEGFR-2) is critically involved in cancer angiogenesis. Blocking of VEGFR-2 signaling pathway proved effective suppression of... 相似文献