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1.
2.
Briana L. Simms Nan Ji Indika Chandrasiri Mohammad Farid Zia Chinwe S. Udemgba Ravinder Kaur Jared H. Delcamp Alex Flynt Chalet Tan Davita L. Watkins 《Journal of polymer science. Part A, Polymer chemistry》2021,59(19):2177-2192
Here, we demonstrate the applicability of self-assembling linear-dendritic block copolymers (LDBCs) and their nanoaggregates possessing varied surfaces as therapeutic nanocarriers. These LDBCs are comprised of a hydrophobic, linear polyester chemically coupled to a hydrophilic dendron polyamidoamine (PAMAM)—the latter of which acts as the surface of the self-assembled nanoaggregate in aqueous media. To better understand how surface charge density affects the overall operability of these nanomaterials, we modified the nanoaggregate surface to yield cationic (NH3+), neutral (OH), and anionic (COO−) surfaces. The effect of these modifications on the physicochemical properties (i.e., size, morphology, and surface charge density), colloidal stability, and cellular uptake mechanism of the polymeric nanocarrier were investigated. This comparative study demonstrates the viability of nanoaggregates formed from PDLLA-PAMAM LDBCs to serve as nanocarriers for applications in drug delivery. 相似文献
3.
F. Prez-Willard C. Sürgers H. Von Lhneysen P. Pfundstein 《Physica E: Low-dimensional Systems and Nanostructures》2004,22(4):872-880
The electronic transport through nanostructured bismuth nanobridges has been investigated at low temperatures (T<2 K) and in magnetic fields B up to 8.5 T. The samples show reproducible resistance fluctuations as a function of B, superimposed on a large magnetoresistance of up to 50%. In addition, time-dependent resistance fluctuations in zero magnetic field demonstrate the presence of bistable scatterers in the constriction region of our samples, which are described by two-level systems. Their dynamics are shown to be sensitive to subtle modifications of the static scatterer configuration in their vicinity, which cannot be detected in the sample magnetofingerprint. 相似文献
4.
Alex Hellsten 《Archive for Mathematical Logic》2006,45(6):705-714
We extract some properties of Mahlo’s operation and show that some other very natural operations share these properties. The weakly compact sets form a similar hierarchy as the stationary sets. The height of this hierarchy is a large cardinal property connected to saturation properties of the weakly compact ideal. 相似文献
5.
Yiming Huai Mahendra PakalaZhitao Diao Dmytro ApalkovYunfei Ding Alex Panchula 《Journal of magnetism and magnetic materials》2006
Spin-transfer driven switching was observed in MgO based magnetic tunnelling junctions (MTJ) with tunnelling magnetoresistance ratio of up to 160% and the average intrinsic switching current density (Jc0) down to 2 MA/cm2, which are the best known results reported in spin-transfer switched MTJ nanostructures. Based on a comparison of results both from MgO and AlOx MTJs, further switching current decrease via MgO dual structures with two pinned layers is discussed. 相似文献
6.
The stannous chloride dihydrate-mediated deprotection-bicyclisation of a range of amides possessing a pendant acetal group is reported. These mild reaction conditions have been used to prepare a number of ring-fused heterocyclic compounds, some in enantiomerically pure form, which should be of interest both in their own right and as building blocks for the production of more complex target molecules. 相似文献
7.
We study property (T) and the fixed-point property for actions on L
p
and other Banach spaces. We show that property (T) holds when L
2 is replaced by L
p
(and even a subspace/quotient of L
p
), and that in fact it is independent of 1≤p<∞. We show that the fixed-point property for L
p
follows from property (T) when 1<p< 2+ε. For simple Lie groups and their lattices, we prove that the fixed-point property for L
p
holds for any 1< p<∞ if and only if the rank is at least two. Finally, we obtain a superrigidity result for actions of irreducible lattices
in products of general groups on superreflexive spaces.
Bader partially supported by ISF grant 100146; Furman partially supported by NSF grants DMS-0094245 and DMS-0604611; Gelander
partially supported by NSF grant DMS-0404557 and BSF grant 2004010; Monod partially supported by FNS (CH) and NSF (US). 相似文献
8.
Kristin Fischer Silvio Prause Stefan Spange Frank Cichos Christian Von Borczyskowski 《Journal of Polymer Science.Polymer Physics》2003,41(11):1210-1218
Solvent‐dependent ultraviolet–visible (UV–vis) absorption and Stokes shifts including strong hydrogen‐bond‐donating (HBD) solvents such as 2,2,2‐trifluoroethanol and 1,1,1,3,3,3‐hexafluoro‐2‐propanol of two coumarine dyes (Co 151 and Co 153) were analyzed with multiple‐square analyses of linear solvation energy relationships and the Kamlet–Taft solvent parameter set to α (HBD capacity), β (hydrogen‐bond‐accepting capacity), and π* (dipolarity/polarizability). The UV–vis absorption and emission spectra of Co 151 and Co 153 were measured when adsorbed on various polysaccharides such as different cellulose batches, carboxymethylcelluloses with different degrees of substitution, and chitine. As a result of this evaluation, Co 153 is recommended as an alternative UV–vis probe for evaluating the dipolarity/polarizability of cellulose and cellulose derivates. Multiple adsorption of Co 153 on Linters cellulose took place indicating a wide‐surface polarity distribution, which makes the determination of a rigid polarity parameter questionable. Thus, fluorescence measurements of adsorbed Co 153 are suitable to detect inhomogenities on a surface but not for the determination of empirical polarity parameters. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1210–1218, 2003 相似文献
9.
Elon Santos Correa Maria Teresinha A. Steiner Alex A. Freitas Celso Carnieri 《Numerical Algorithms》2004,35(2-4):373-388
Facility-location problems have several applications, such as telecommunications, industrial transportation and distribution. One of the most well-known facility-location problems is the p-median problem. This work addresses an application of the capacitated p-median problem to a real-world problem. We propose a genetic algorithm (GA) to solve the capacitated p-median problem. The proposed GA uses not only conventional genetic operators, but also a new heuristic “hypermutation” operator suggested in this work. The proposed GA is compared with a tabu search algorithm. 相似文献
10.
D. Hugh Powell Andr E. Merbach Gabriel Gonzlez Ern Brücher Kroly Micskei M. Francesca Ottaviani Klaus Khler Alex Von Zelewsky Oleg Ya. Grinberg Yakob S. Lebedev 《Helvetica chimica acta》1993,76(5):2129-2146
EPR Spectra have been measured for aqueous solutions of a series of Gd3+ complexes at variable temperature and a range of magnetic fields; S-band (0.14 T), X-band (0.34 T), Q-band (1.2 T), and 2-mm-band (5.0 T). The major contribution to the observed line widths is magnetic-field-dependent and is interpreted as being due to the modulation of the zero-field splitting produced by distortion of the complexes from perfect symmetry. The transverse and longitudinal relaxation matrices for an 8S ion with such an interaction have been calculated using Redfield theory with vector-coupling methods, and diagonalised numerically to obtain relaxation rates and intensities for the degenerate transitions which contribute to the multiplet. The observed line width, which is inversely proportional to the magnetic field at low temperatures, is best described by the intensity-weighted mean transverse relaxation time for the four transitions with non-zero intensity. A least-squares fit of the data yields the square of the zero-field splitting tensor, Δ2, and a correlation time, τv, with activation energy, Ev. The physical significance of these parameters and the extent of validity of the theoretical approach are considered. The parameters are used to predict the magnetic-field dependence of the longitudinal and transverse electronic relaxation times, which are discussed in the context of their relevance to 1H-NMR relaxivity. 相似文献