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61.
62.
A Cutler T Otake L Bruggeman 《The Journal of the Acoustical Society of America》2012,132(2):EL155-EL160
Studies of spoken-word recognition have revealed that competition from embedded words differs in strength as a function of where in the carrier word the embedded word is found and have further shown embedding patterns to be skewed such that embeddings in initial position in carriers outnumber embeddings in final position. Lexico-statistical analyses show that this skew is highly attenuated in Japanese, a noninflectional language. Comparison of the extent of the asymmetry in the three Germanic languages English, Dutch, and German allows the source to be traced to a combination of suffixal morphology and vowel reduction in unstressed syllables. 相似文献
63.
Desmond Heng Keiko Ogawa David J. Cutler Hak-Kim Chan Judy A. Raper Lin Ye Jimmy Yun 《Journal of nanoparticle research》2010,12(5):1743-1754
There has been increasing interests for drug companies to incorporate drug nanoparticles into their existing formulations.
However, technical knowledge in this area is still in its infancy and more study needs to be done to stimulate growth in this
fledging field. There is a need to scrutinize the performance of pure drug nanoparticles in tablets, particularly relating
formulation variables to their dissolution performance. Application of the pure form, synthesized without the use of surfactants
or stabilizers, is often preferred to maximize drug loading and also to minimize toxicity. Cefuroxime axetil, a poorly water-soluble
cephalosporin antibiotic, was used as the model drug in the formulation development. Drug release rate, tablet disintegration
time, tensile strength and energy of failure were predominantly influenced by the amount of super-disintegrant, amount of
surfactant, compression force and diluent species, respectively. The compression rate had minimal impact on the responses.
The main hurdle confronting the effective use of pure drug nanoparticles in tablets is the difficulty in controlling aggregation
in solution, which could potentially be aggravated by the tabletting process. Through the use of elevated levels of surfactants
(8 w/w% sodium dodecyl sulphate), drug release from the nanoparticle preparation was enhanced from 58.0 ± 2.7% to 72.3 ± 0.7%
in 10 min. Hence, it is recommended that physical formulations for pure drug nanoparticles be focused on the particle de-aggregation
step in solution, if much higher rates are to be desired. In conclusion, even though pure drug nanoparticles could be easily
synthesized, limitations from aggregation may need to be overcome, before successful application in tablets can be fully realized. 相似文献
64.
We present an algorithm for finding the global maximum of a multimodal, multivariate function for which derivatives are available. The algorithm assumes a bound on the second derivatives of the function and uses this to construct an upper envelope. Successive function evaluations lower this envelope until the value of the global maximum is known to the required degree of accuracy. The algorithm has been implemented in RATFOR and execution times for standard test functions are presented at the end of the paper.Partially supported by NSF DMS-8718362. 相似文献
65.
K. V. Katti R. Kannan K. Katti V. Kattumori R. Pandrapraganda V. Rahing C. Cutler E. J. Boote S. W. Casteel C. J. Smith J. D. Robertson S. S. Jurrison 《Czechoslovak Journal of Physics》2006,56(1):D23-D34
Metallic nanoparticles, because of their size, chemical and physical properties, are particularly attractive as therapeutic
probes in treating cancer. Central to any clinical advances in nanoparticulate based therapy will be to produce hybrid nanoparticles
that can be targeted to vascular, extracellular or cell surface receptors. Development of hybrid nanoparticles that specifically
target cancer vasculature has received considerable attention. Most cancers have leaky vasculature and the defective vascular
architecture, created due to the rapid vascularization necessary to serve fast growing cancers, in combination with poor lymphatic
drainage allows increased permeation and retention effects. The leaky vasculature, because of higher porosity and permeability,
serve as natural high affinity targets to metallic nanoparticles. Another attractive approach toward the application of nanotechnology
to nanomedicine is the utility of nanoparticles that display inherent therapeutic properties. For example radioactive gold
nanoparticles present attractive prospects in therapy of cancer. The radioactive properties of Au-198 (βmax=0.96 MeV; t1/2=2.7 d) and Au-199 (βmax=0.46 MeV; t1/2=3.14 d) make them ideal candidates for use in radiotherapeutic applications. In addition, they both have imageable gamma
emissions for dosimetry and pharmacokinetic studies and Au-199 can be made carrier-free by indirect methods. Gold nanoparticles
are of interest for treatment of disease as they can deliver agents directly into cells and cellular components with a higher
concentration of radioactivity, e.g. higher dose of radioactivity, to cancerous tumor cells. 相似文献
66.
Probe measurements were performed in the flow field produced by injection of helium or air into a supersonic airstream. The
injectant was seeded with water and Rayleigh scattering was used to image the injectant plume. The region of the flow containing
injectant–air mixture is seen to be highly unsteady, leading to the intermittent presence of injectant in certain regions.
The intermittency is inferred. It is shown that bias errors can occur when the probe data is analyzed by techniques which
assume steady flow. A technique for relatively bias-free analysis utilizing the intermittency measurements is presented and
the bias errors are estimated. The gas-sampling probe is shown to measure the mass-weighted-mean mass fraction of helium,
which is significantly less than the simple mean. A new measure of mixing efficiency obtained from the combined probe and
intermittency measurements is discussed.
Received: 2 February 1996/Accepted: 2 December 1996 相似文献
67.
怀孕期头发中一些元素含量的变化趋势 总被引:5,自引:1,他引:4
用同步辐射激发X射线荧光分析,对11个产妇怀孕期间头发内一些元素含量的变化趋势进行了测量,在各自对比的基础上,得到了一些结果。 相似文献
68.
69.
70.
Asymptotic expressions for the distribution of the eigenvalues of the Helmholtz-Schrödinger equation are used to anlyze the dependence of the Fermi energy, EF, and the density of states, ρ(E), on sample size, shape, and electron density, in a free-electron model with Dirichlet boundary conditions. It is found that for very small samples EF is increased relative to its asymptotic (i.e., bulk) value and ρ(E) is decreased relative to its bulk value. These effects are more pronounced for samples with low electron density and with a large surface-to-volume ratio. In general EF and ρ(EF) deviate significantly from their bulk values only for systems with fewer than 50,000 electrons and/or with linear dimensions of 100 Å or less. The use of smoothing functions to represent the density of states obtained from the exact eigenvalue distribution is also discussed. It is shown that an oscillating density of states leads to small cusps in the plot of EF as a function of sample size. This is in qualitative agreement with the results of experiments on size-dependent oscillations in field emission from thin metallic films. Comparison is also made between photoemission experiments from thin films and other results obtained in this study. 相似文献