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111.
112.
Preparation, characterization and surface study of poly-epsilon caprolactone magnetic microparticles
Magnetic microparticles (MMP) have shown to be applied in increasing applications in various fields of biotechnology and medicine. One of their most promising utilization is the magnetic resonance imaging (MRI) in which superparamagnetic substances as magnetite are used in a nanometric size (less than 30 nm) and encapsulated within locally injected biodegradable microparticles. In this paper, magnetite has been encapsulated in polymer-based microparticles. The MMP have been prepared by an emulsion evaporation method. The different parameters influencing the particles size were investigated. The size was found to decrease as the stirring speed or the stabilizer amount (to certain limit) increases. The encapsulation efficacy was more than 90% yielding a magnetite loading of up to 30%, w/w. The X-ray photoelectron spectroscopy (XPS) showed less than 2% of iron atoms at the microparticles surface. The zeta potential response of MMP towards pH variation was very similar to that of magnetite-free microparticles confirming the encapsulation of magnetite within the microparticles. X-ray diffraction assays showed that magnetite crystalline structure was conserved after emulsification and MMP formation. Vibration simple magnetometer (VSM) showed a superparamagnetic profile of the MMP with a magnetic saturation increasing with the increased magnetite amount in the microparticles. These magnetic microparticles can enable clinicians to control microparticles distribution after a local administration in tumors by MRI. They can also be administered to target a defined tumor area by focusing a magnetic field on the surfaces covering the cancerous tissue. 相似文献
113.
A reagent tablet for determination of fluoride ion has been prepared using ethylenediamine-N,N,N′,N′-tetraacetate complex of zirconium (Zr-EDTA), 3-hydroxy-2′-flavone (FS) and an appropriate pH buffer. Dissolving of the tablet into water exhibits an intense blue fluorescence (λmax = 460 nm) upon excitation at 377 nm and the fluorescence intensity decreases with the presence of fluoride ion. Hence, a simple fluorescent detection procedure for fluoride ion in aqueous media was successfully constructed with this tablet. The principle of this detection system is the ligand exchange reaction of FS bound to Zr-EDTA with fluoride ion. The present system provides an easy, rapid and selective determination method of fluoride ion ranging from 5 × 10−6 to 1 × 10−3 mol dm−3. The measurement of real samples with this tablet showed the similar results as those by the common method with the Alfusone reagent. 相似文献
114.
115.
A renormalization group method is used to construct approximants for the magnetization,m, and the static structure factor,
(q), for the simple cubic Ising model. Using the best values for the thermal critical index, the transition temperature, and the nearest-neighbor correlation function as input, we obtain recursion relations form and
(q) which lead to reasonable results over a wide range of temperatures and wave numbers. 相似文献
116.
本文介绍了一个根据具体城市情况制定的零售贸易餐饮业的抽样调查方案.以长沙市规模以下零售业、餐饮业为总体,用区域抽样代替一般的名录抽样,并采用细致的分层解决商业单位分布不均匀问题.文中也给出了与抽样方案配套的总体和域目标量的估计及相应的方差估计公式. 相似文献
117.
The Lie admissible non-associative algebra is defined in the papers [Seul Hee Choi, Ki-Bong Nam, Derivations of a restricted Weyl type algebra I, Rocky Mountain J. Math. 37 (6) (2007) 1813–1830; Seul Hee Choi, Ki-Bong Nam, Weyl type non-associative algebra using additive groups I, Algebra Colloq. 14 (3) (2007) 479–488; Ki-Bong Nam, On Some Non-associative Algebras using Additive Groups, Southeast Asian Bull. Math., vol. 27, Springer-Verlag, 2003, 493–500]. We define in this work the algebra which generalizes the previous one and is not Lie admissible. We prove that the antisymmetrized Lie algebra is simple and contains the simple Lie algebra . We also prove that the matrix ring is embedded in . 相似文献
118.
Sally Kuhlmann 《Geometriae Dedicata》2008,131(1):181-211
We consider the existence of simple closed geodesics or “geodesic knots” in finite volume orientable hyperbolic 3-manifolds.
Every such manifold contains at least one geodesic knot by results of Adams, Hass and Scott in (Adams et al. Bull. London
Math. Soc. 31: 81–86, 1999). In (Kuhlmann Algebr. Geom. Topol. 6: 2151–2162, 2006) we showed that every cusped orientable hyperbolic 3-manifold in fact contains infinitely many geodesic
knots. In this paper we consider the closed manifold case, and show that if a closed orientable hyperbolic 3-manifold satisfies
certain geometric and arithmetic conditions, then it contains infinitely many geodesic knots. The conditions on the manifold
can be checked computationally, and have been verified for many manifolds in the Hodgson-Weeks census of closed hyperbolic
3-manifolds. Our proof is constructive, and the infinite family of geodesic knots spiral around a short simple closed geodesic
in the manifold.
相似文献
119.
120.
Dividing chains have been used as conditions to isolate adequate subclasses of simple theories. In the first part of this
paper we present an introduction to the area. We give an overview on fundamental notions and present proofs of some of the
basic and well-known facts related to dividing chains in simple theories. In the second part we discuss various characterizations
of the subclass of low theories. Our main theorem generalizes and slightly extends a well-known fact about the connection
between dividing chains and Morley sequences (in our case: independent sequences). Moreover, we are able to give a proof that
is shorter than the original one. This result motivates us to introduce a special property of formulas concerning independent
dividing chains: For any dividing chain there exists an independent dividing chain of the same length. We study this property
in the context of low, short and ω -categorical simple theories, outline some examples and define subclasses of low and short theories, which imply this property.
The results give rise to further studies of the relationships between some subclasses of simple theories.
Research supported by CNPq grant 150309/2003-1.
Research supported by CNPq grant 304365/2003-3 (Modelos, Provas e Algoritmos) 相似文献